FN Thomson Reuters Web of Science™ VR 1.0 PT J AU Villagrasa-Canton, C Boudard, A Ducret, JE Fernandez, B Leray, S Volant, C Armbruster, P Enqvist, T Hammache, F Helariutta, K Jurado, B Ricciardi, MV Schmidt, KH Summerer, K Vives, F Yordanov, O Audouin, L Bacri, CO Ferrant, L Napolitani, P Rejmund, F Stephan, C Tassan-Got, L Benlliure, J Casarejos, E Fernandez-Ordonez, M Pereira, J Czajkowski, S Karamanis, D Pravikoff, M George, JS Mewaldt, RA Yanasak, N Wiedenbeck, M Connell, JJ Faestermann, T Heinz, A Junghans, A AF Villagrasa-Canton, C. Boudard, A. Ducret, J.-E. Fernandez, B. Leray, S. Volant, C. Armbruster, P. Enqvist, T. Hammache, F. Helariutta, K. Jurado, B. Ricciardi, M.-V. Schmidt, K.-H. Suemmerer, K. Vives, F. Yordanov, O. Audouin, L. Bacri, C.-O. Ferrant, L. Napolitani, P. Rejmund, F. Stephan, C. Tassan-Got, L. Benlliure, J. Casarejos, E. Fernandez-Ordonez, M. Pereira, J. Czajkowski, S. Karamanis, D. Pravikoff, M. George, J. S. Mewaldt, R. A. Yanasak, N. Wiedenbeck, M. Connell, J. J. Faestermann, T. Heinz, A. Junghans, A. TI Spallation residues in the reaction Fe-56+p at 0.3A, 0.5A, 0.75A, 1.0A, and 1.5A GeV SO PHYSICAL REVIEW C LA English DT Article ID PRODUCTION CROSS-SECTIONS; INTRANUCLEAR CASCADE CALCULATION; PROTON-INDUCED REACTIONS; LIQUID-HYDROGEN TARGET; NUCLEAR-REACTIONS; RELATIVISTIC NUCLEI; CARBON TARGETS; NEUTRON-PRODUCTION; NUCLIDE PRODUCTION; FISSION-RESIDUES AB The spallation residues produced in the bombardment of Fe-56 at 1.5A,1.0A,0.75A,0.5A, and 0.3A GeV on a liquid-hydrogen target have been measured using the reverse kinematics technique and the fragment separator at GSI (Darmstadt). This technique has permitted the full identification in charge and mass of all isotopes produced with cross sections larger than 10(-2) mb down to Z=8. Their individual production cross sections and recoil velocities at the five energies are presented. Production cross sections are compared with previously existing data and with empirical parametric formulas, often used in cosmic-ray astrophysics. The experimental data are also extensively compared with the results of different combinations of intranuclear cascade and deexcitation models. It is shown that the yields of the lightest isotopes cannot be accounted for by standard evaporation models. The GEMINI model, which includes an asymmetric fission decay mode, gives an overall good agreement with the data. These experimental data can be directly used for the estimation of composition modifications and damages in materials containing iron in spallation sources. They are also useful for improving high-precision cosmic-ray measurements. C1 CEA Saclay, DAPNIA, SPhN, F-91191 Gif Sur Yvette, France. GSI Darmstadt, D-64291 Darmstadt, Germany. Inst Phys Nucl, F-91406 Orsay, France. Univ Santiago de Compostela, Santiago De Compostela 15706, Spain. Univ Bordeaux 1, CNRS, UMR 5797, IN2P3,CEN Bordeaux Gradignan, F-33175 Gradignan, France. CALTECH, Pasadena, CA 91125 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ New Hampshire, Durham, NH 03824 USA. Tech Univ Munich, D-85747 Garching, Germany. Argonne Natl Lab, Argonne, IL 60439 USA. Inst Strahlenphys, D-01314 Dresden, Germany. RP Villagrasa-Canton, C (reprint author), IRSN, BP 17, F-92262 Fontenay Aux Roses, France. EM Alain.Boudard@cea.fr RI Heinz, Andreas/E-3191-2014; Junghans, Arnd/D-4596-2012; Beatriz, Fernandez-Dominguez/I-2631-2015; Casarejos, Enrique/A-5865-2015; Hammache, Fairouz/K-6132-2016; Leray, Sylvie/A-3924-2012; Benlliure, Jose/K-8407-2014 OI Beatriz, Fernandez-Dominguez/0000-0001-7859-2438; Casarejos, Enrique/0000-0001-5066-3644; Leray, Sylvie/0000-0002-1942-2911; Benlliure, Jose/0000-0002-5114-1298 NR 66 TC 47 Z9 49 U1 1 U2 3 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2469-9985 EI 2469-9993 J9 PHYS REV C JI Phys. Rev. C PD APR PY 2007 VL 75 IS 4 AR 044603 DI 10.1103/PhysRevC.75.044603 PG 26 WC Physics, Nuclear SC Physics GA 162HB UT WOS:000246076400028 ER PT J AU Wolf, S Moro-Martin, A D'Angelo, G AF Wolf, Sebastian Moro-Martin, Amaya D'Angelo, Gennaro TI Signatures of planets in protoplanetary and debris disks SO PLANETARY AND SPACE SCIENCE LA English DT Article; Proceedings Paper CT Symposium on Exoplanets and Planetary Formation CY APR 25-30, 2004 CL Nice, FRANCE SP European Geosci Union DE protoplanelary disk; debris disk; planet formation; planet-disk interaction; radiative transfer simulation ID PICTORIS DUST DISK; KUIPER-BELT DUST; SOLAR-TYPE STARS; YOUNG STELLAR OBJECTS; MAIN-SEQUENCE STARS; BETA-PICTORIS; GIANT PLANETS; CIRCUMSTELLAR DISK; MOLECULAR GAS; INTERPLANETARY DUST AB We discuss selected possibilities to detect planets in circumstellar disks. We consider the search for characteristic signatures in these disks caused by the interaction of giant planets with the disk as the most promising approach. Numerical simulations show that these signatures are usually much larger in size than the planet itself and thus much easier to detect. The particular result of the planet-disk interaction depends Dirt the evolutionary stage of the disk. Primary signatures of planets embedded in disks are gaps in the case of young disks and characteristic asymmetric density patterns in debris disks. We present simulations which demonstrate that high spatial resolution observations performed with instruments/telescopes that will become available in the near future will be able to trace the location and other properties of young and evolved planets. These observations will allow to directly investigate the formation and evolution of planets in protoplanetary and debris disks. (c) 2006 Elsevier Ltd. All rights reserved. C1 Max Planck Inst Astron, D-69117 Heidelberg, Germany. Princeton Univ, Dept Astrophys Sci, Princeton, NJ 08544 USA. Univ Exeter, Sch Phys, Exeter EX4 4QL, Devon, England. NASA, Ames Res Ctr, Space Sci & Astrobiol Div, Moffett Field, CA 94035 USA. RP Wolf, S (reprint author), Max Planck Inst Astron, Konigstuhl 17, D-69117 Heidelberg, Germany. EM swolf@mpia.de; amaya@astro.princeton.edu; gennaro@astro.ex.ac.uk RI D'Angelo, Gennaro/L-7676-2014 OI D'Angelo, Gennaro/0000-0002-2064-0801 NR 92 TC 15 Z9 15 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0032-0633 J9 PLANET SPACE SCI JI Planet Space Sci. PD APR PY 2007 VL 55 IS 5 BP 569 EP 581 DI 10.1016/j.pss.2006.04.035 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 157SW UT WOS:000245742200004 ER PT J AU Vassiliadis, D Mann, IR Fung, SF Shao, X AF Vassiliadis, D. Mann, I. R. Fung, S. F. Shao, X. TI Ground Pc3-Pc5 wave power distribution and response to solar wind velocity variations SO PLANETARY AND SPACE SCIENCE LA English DT Article; Proceedings Paper CT Chapman Conference on Magnetospheric ULF Waves CY MAR 21-25, 2005 CL San Diego, CA SP NASA, NSF DE solar wind-magnetosphere coupling; ULF magnetospheric waves; magnetic storms; viscous interaction; high-speed stream ID RELATIVISTIC ELECTRONS; STATISTICAL-ANALYSIS; INNER MAGNETOSPHERE; GEOMAGNETIC STORMS; IMPULSE-RESPONSE; ENERGY-TRANSFER; MAGNETIC-FIELD; ACCELERATION; PLASMAPAUSE; DEPENDENCE AB We examine the magnetospheric wave power in the Pc3-Pc5 range in terms of its growth and decay characteristics and its distribution in L shell in response to the interplanetary plasma bulk velocity, Vsw. We use linear and nonlinear (rank-order) correlation and filtering methods to quantify the effective coupling of the wave power to Vsw variations. These methods are applied to measurements from 26 ground magnetometers of the IMAGE array and NOAA's GOES-10 spacecraft at geosynchronous orbit, taken over 2 years of solar-maximum activity (2002-2003). We find that the ground ULF wave power is structured in the range 3.5 < L < 6.4 and distributed uniformly in the range 6.4 < L < 15 (uncertainties in L are estimated to be +/- 0.5). The response of the wave power to the V-sw is characterized by an increase starting 3 days before the V-sw peak, intensifying several hours before the peak, and is followed by a fast decrease in the next 2 days. The rapid decay of ULF waves has two stages: one at tau = - 6 +/- 2 h before the solar wind velocity reaches its peak, and one at the V-sw peak, tau = 0. We suggest that the first one is brought about by wave-particle interaction with innermagnetospheric populations while the second one is a dV(sw)/dt effect. The correlation results are confirmed by calculating the finite-impulse response, which shows clearly the decay of the ULF waves after the V-sw peak. The response of the wave power at geosynchronous orbit is remarkably similar to that of the ground wave power at comparable L shells. The above findings characterize the inner-magnetospheric response to interplanetary high-speed streams, as opposed to the more short-lived, higher-amplitude response to CMEs. (c) 2006 Elsevier Ltd. All rights reserved. C1 NASA, Goddard Space Flight Ctr, Huntsville, AL 35812 USA. Univ Alberta, Dept Phys, Edmonton, AB T6G 2M7, Canada. Univ Maryland, Dept Astron, College Pk, MD 20742 USA. RP Vassiliadis, D (reprint author), NASA, Goddard Space Flight Ctr, ST Code 673, Huntsville, AL 35812 USA. EM Vassi@electra.gsfc.nasa.gov RI Fung, Shing/F-5647-2012 NR 31 TC 7 Z9 7 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0032-0633 J9 PLANET SPACE SCI JI Planet Space Sci. PD APR PY 2007 VL 55 IS 6 BP 743 EP 754 DI 10.1016/j.pss.2006.03.012 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 168HU UT WOS:000246515200008 ER PT J AU Khazanov, GV Tel'nikhin, AA Kronberg, TK AF Khazanov, G. V. Tel'nikhin, A. A. Kronberg, Tatiana K. TI Chaotic motion of relativistic electrons driven by whistler waves SO PLASMA PHYSICS AND CONTROLLED FUSION LA English DT Article ID JOVIAN MAGNETOSPHERE; PARTICLE; DIFFUSION; JUPITER; PACKET; FIELD AB Canonical equations governing an electron motion in the electromagnetic field of the whistler mode waves propagating along the direction of an ambient magnetic field are derived. The physical processes on which the equations of motion are based are identified. It is shown that relativistic electrons interacting with these fields demonstrate chaotic motion, which is accompanied by particle stochastic heating and significant pitch angle diffusion. Evolution of distribution functions is described by the Fokker-Planck-Kolmogorov equations. It is shown that the whistler mode waves could provide a viable mechanism for stochastic energization of electrons with energies of up to 50 MeV in the Jovian magnetosphere. C1 NASA, Marshall Space Flight Ctr, Natl Space Sci & Technol Ctr, Huntsville, AL 35805 USA. Altai State Univ, Dept Phys, Barnaul 656049, Russia. RP Khazanov, GV (reprint author), NASA, Marshall Space Flight Ctr, Natl Space Sci & Technol Ctr, 320 Sparkman Dr, Huntsville, AL 35805 USA. EM tatiana.kronberg@list.ru NR 25 TC 9 Z9 9 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0741-3335 J9 PLASMA PHYS CONTR F JI Plasma Phys. Control. Fusion PD APR PY 2007 VL 49 IS 4 BP 447 EP 466 DI 10.1088/0741-3335/49/4/008 PG 20 WC Physics, Fluids & Plasmas SC Physics GA 153MI UT WOS:000245439200009 ER PT J AU Silk, EA Creel, R AF Silk, E. A. Creel, R. TI Technology development for lunar thermal applications and the next generation of space exploration SO PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART G-JOURNAL OF AEROSPACE ENGINEERING LA English DT Article DE lunar exploration; advanced thermal control AB In recent years, NASA has shown a renewed interest in Lunar exploration. This renewed interest is expected to spawn a new era of exploration into the solar system, as well as generate new residual technologies for earth application. A review of experiences on the prior Apollo missions shows that there are significant challenges associated with returning to and establishing a base for humans in the harsh Lunar environment. The present article is a high level overview of the effort to return to the Moon, in the context of a larger effort towards human expansion farther into the solar system. Also included is a review of technical challenges associated with returning to the Moon. C1 NASA, Goddard Space Flight Ctr, Thermal Engn Technol Dev Grp, Thermal Engn Branch, Greenbelt, MD 20771 USA. Ryan Associates Inc, Gloucester, MA USA. RP Silk, EA (reprint author), NASA, Goddard Space Flight Ctr, Thermal Engn Technol Dev Grp, Thermal Engn Branch, Code 545-0,Bldg 7,Room 215, Greenbelt, MD 20771 USA. EM eric.a.silk@nasa.gov NR 9 TC 3 Z9 3 U1 0 U2 3 PU PROFESSIONAL ENGINEERING PUBLISHING LTD PI WESTMINISTER PA 1 BIRDCAGE WALK, WESTMINISTER SW1H 9JJ, ENGLAND SN 0954-4100 J9 P I MECH ENG G-J AER JI Proc. Inst. Mech. Eng. Part G-J. Aerosp. Eng. PD APR PY 2007 VL 221 IS G2 BP 305 EP 309 DI 10.1243/09544100JAERO170 PG 5 WC Engineering, Aerospace; Engineering, Mechanical SC Engineering GA 173IX UT WOS:000246867800014 ER PT J AU Phillips, MM Li, WD Frieman, JA Blinnikov, SI DePoy, D Prieto, JL Milne, P Contreras, C Folatelli, G Morrell, N Hamuy, M Suntzeff, NB Roth, M Gonzalez, S Krzeminski, W Filippenko, AV Freedman, WL Chornock, R Jha, S Madore, BF Persson, SE Burns, CR Wyatt, P Murphy, D Foley, RJ Ganeshalingam, M Serduke, FJD Krisciunas, K Bassett, B Becker, A Dilday, B Eastman, J Garnavich, PM Holtzman, J Kessler, R Lampeitl, H Marriner, J Frank, S Marshall, JL Miknaitis, G Sako, M Schneider, DP Van Der Heyden, K Yasuda, N AF Phillips, M. M. Li, Weidong Frieman, Joshua A. Blinnikov, S. I. DePoy, Darren Prieto, Jose L. Milne, P. Contreras, Carlos Folatelli, Gaston Morrell, Nidia Hamuy, Mario Suntzeff, Nicholas B. Roth, Miguel Gonzalez, Sergio Krzeminski, Wojtek Filippenko, Alexei V. Freedman, Wendy L. Chornock, Ryan Jha, Saurabh Madore, Barry F. Persson, S. E. Burns, Christopher R. Wyatt, Pamela Murphy, David Foley, Ryan J. Ganeshalingam, Mohan Serduke, Franklin J. D. Krisciunas, Kevin Bassett, Bruce Becker, Andrew Dilday, Ben Eastman, J. Garnavich, Peter M. Holtzman, Jon Kessler, Richard Lampeitl, Hubert Marriner, John Frank, S. Marshall, J. L. Miknaitis, Gajus Sako, Masao Schneider, Donald P. Van Der Heyden, Kurt Yasuda, Naoki TI The peculiar SN 2005hk: Do some type ia supernovae explode as deflagrations? SO PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF THE PACIFIC LA English DT Article ID DIGITAL SKY SURVEY; HUBBLE-SPACE-TELESCOPE; LIGHT CURVES; MAXIMUM LIGHT; INFRARED PHOTOMETRY; STANDARD STARS; LEGACY SURVEY; RISE-TIME; CONSTANT; SPECTRA AB We present extensive u'g'r'i'BVRIYJHK(s) photometry and optical spectroscopy of the Type Ia supernova ( SN) 2005hk. These data reveal that SN 2005hk was nearly identical in its observed properties to SN 2002cx, which has been called "the most peculiar known Type Ia supernova." Both supernovae exhibited high-ionization SN 1991T-like premaximum spectra, yet low peak luminosities like that of SN 1991bg. The spectra reveal that SN 2005hk, like SN 2002cx, exhibited expansion velocities that were roughly half those of typical Type Ia supernovae. The R and I light curves of both supernovae were also peculiar in not displaying the secondary maximum observed for normal Type Ia supernovae. Our YJH photometry of SN 2005hk reveals the same peculiarity in the near-infrared. By combining our optical and near-infrared photometry of SN 2005hk with published ultraviolet light curves obtained with the Swift satellite, we are able to construct a bolometric light curve from similar to 15 days before to similar to 60 days after B maximum. The shape and unusually low peak luminosity of this light curve, plus the low expansion velocities and absence of a secondary maximum at red and near-infrared wavelengths, are all in reasonable agreement with model calculations of a three-dimensional deflagration that produces similar to 0.2 M-circle dot of Ni-56. C1 Carnegie Observ, Las Campanas Observ, La Serena, Chile. Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA. Univ Chicago, Dept Astron & Astrophys, Chicago, IL 60637 USA. Univ Chicago, Kavli Inst Cosmol Phys, Chicago, IL 60637 USA. Fermilab Natl Accelerator Lab, Batavia, IL 60510 USA. Inst Theoret & Expt Phys, Moscow 117259, Russia. Max Planck Inst Astrophys, D-85741 Garching, Germany. Ohio State Univ, Dept Astron, Columbus, OH 43210 USA. Univ Arizona, Steward Observ, Tucson, AZ USA. Univ Chile, Dept Astron, Santiago, Chile. Texas A&M Univ, Dept Phys, College Stn, TX 77843 USA. Observ Carnegie Inst Washington, Pasadena, CA 91101 USA. Stanford Linear Accelerator Ctr, Kavli Inst Particle Astrophys & Cosmol, Menlo Pk, CA USA. CALTECH, Jet Prop Lab, Infrared Proc & Anal Ctr, Pasadena, CA 91125 USA. Univ Notre Dame, Dept Phys & Astron, Notre Dame, IN USA. S African Astron Observ, Cape Town, South Africa. Univ Cape Town, Appl Math Dept, Cape Town, South Africa. Univ Washington, Dept Astron, Seattle, WA USA. Univ Chicago, Dept Phys, Chicago, IL USA. New Mexico State Univ, Dept Astron, Las Cruces, NM USA. Univ Chicago, Ctr Astrophys Thermonucl Flashes, Chicago, IL USA. Space Telescope Sci Inst, Baltimore, MD USA. Univ Penn, Dept Phys & Astron, Philadelphia, PA USA. Penn State Univ, Dept Astron & Astrophys, University Pk, PA USA. Univ Tokyo, Inst Cosm Ray Res, Kashiwa, Chiba, Japan. RP Phillips, MM (reprint author), Carnegie Observ, Las Campanas Observ, La Serena, Chile. EM mmp@lco.cl; weidong@astro.berkeley.edu; frieman@fnal.gov; sergei.blinnikov@itep.ru; depoy@astronomy.ohio-state.edu; prieto@astronomy.ohio-state.edu; pmilne@as.arizona.edu; ccontreras@lco.cl; gfolatelli@lco.cl; nmorrell@lco.cl; mhamuy@das.uchile.cl; suntzeff@physics.tamu.edu; miguel@lco.cl; sgonzalez@lco.cl; wojtek@lco.cl; alex@astro.berkeley.edu; wendy@ociw.edu; chornock@astro.berkeley.edu; saurabh@slac.stanford.edu; barry@ipac.caltech.edu; persson@ociw.edu; cburns@ociw.edu; plwyatt@ociw.edu; david@ociw.edu; rfoley@astro.berkeley.edu; mganesh@astro.berkeley.edu; Frank@Serduke.com; kkrisciu@nd.edu; bruce@saao.ac.za; becker@astro.washington.edu; bdilday@uchicago.edu; jdeast@astronomy.ohio-state.edu; peter.m.garnavich.1@nd.edu; holz@nmsu.edu; kessler@hep.uchicago.edu; kessler@hep.uchicago.edu; marriner@fnal.gov; Frank@Serduke.com; jmarshall@ociw.edu; gm@fnal.gov; masao@sas.upenn.edu; dps@astro.psu.edu; heyden@saao.ac.za; yasuda@icrr.u-tokyo.ac.jp RI Folatelli, Gaston/A-4484-2011; Yasuda, Naoki/A-4355-2011; Hamuy, Mario/G-7541-2016 NR 83 TC 119 Z9 119 U1 0 U2 5 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-6280 J9 PUBL ASTRON SOC PAC JI Publ. Astron. Soc. Pac. PD APR PY 2007 VL 119 IS 854 BP 360 EP 387 DI 10.1086/518372 PG 28 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 161IS UT WOS:000246008700002 ER PT J AU Ljung, K Bjorck, S Muscheler, R Beer, J Kubik, PW AF Ljung, Karl Bjorck, Svante Muscheler, Raimund Beer, Juerg Kubik, Peter W. TI Variable (10)Be fluxes in lacustrine sediments from Tristan da Cunha, South Atlantic: a solar record? SO QUATERNARY SCIENCE REVIEWS LA English DT Article ID GEOMAGNETIC-FIELD INTENSITY; DEEP-SEA SEDIMENTS; CAL KYR BP; C-14 VARIATIONS; CARBON-CYCLE; BERYLLIUM 10; ICE CORE; CALIBRATION; SUMMIT; OCEAN AB A 650-yr-long sediment sequence from a crater lake on Tristan da Cunha, South Atlantic, was analysed for its (10)Be content. Based on (14)C dating, and sedimentary, geochemical, magnetic and palynological records, the period between 900 and 1450 AD appears to have been unusually stable in terms of sedimentation and vegetation and therefore this period was chosen for analysis of the (10)Be content. During this period of highly organic sedimentation and closed vegetation, the pattern of (10)Be flux variations follows the (10)Be fluctuations from the GRIP ice core and estimated (14)C production rates well. However, before and after this stable period, variable sedimentation rates have to be accounted for to obtain results that are comparable to the established (10)Be/(14)C records. Our data show not only the possibility of obtaining detailed enough (10)Be flux data from sedimentary sequences to reconstruct past solar forcing but also how sensitive this type of record is to sedimentary and environmental changes. If suitable archives can be found, they have the potential to improve reconstructions of solar activity far back in time. (c) 2007 Elsevier Ltd. All rights reserved. C1 Lund Univ, GeoBiosphere Sci Ctr, SE-22362 Lund, Sweden. NASA, Goddard Space Flight Ctr, Climate & Radiat Branch, Greenbelt, MD 20771 USA. EAWAG, CH-8600 Dubendorf, Switzerland. ETH Honggerberg, Paul Scherrer Inst, Inst Particle Phys, CH-8093 Zurich, Switzerland. RP Ljung, K (reprint author), Lund Univ, GeoBiosphere Sci Ctr, Solveg 12, SE-22362 Lund, Sweden. EM karl.ljungo@geol.lu.se NR 29 TC 11 Z9 11 U1 0 U2 4 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0277-3791 J9 QUATERNARY SCI REV JI Quat. Sci. Rev. PD APR PY 2007 VL 26 IS 7-8 BP 829 EP 835 DI 10.1016/j.quascirev.2006.12.016 PG 7 WC Geography, Physical; Geosciences, Multidisciplinary SC Physical Geography; Geology GA 199YX UT WOS:000248732200001 ER PT J AU Gamero-Castano, M AF Gamero-Castano, Manuel TI Induction charge detector with multiple sensing stages SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article AB An induction charge detector yields the net charge and the time of flight of a particle. The unique ability to independently measure these two parameters sets apart this rather simple detection technique. The main shortcoming of this instrument is its high charge detection limit, resulting from the intrinsic noise of the detector electronics and the low signal associated with the charge to measure. The goal of the present work is to lower the detection limit of this detector. This article describes an induction charge detector whose main novelty is a sequence of aligned cylindrical electrodes for measuring the charge of a particle n times. In a time domain analysis, this feature reduces both the detection limit and the standard error of the charge measurement by factors of root 2 and root n. More importantly, sensing stages could be added to arbitrarily lower the detection limit in a frequency domain analysis. (c) 2007 American Institute of Physics. C1 CALTECH, Jet Prop Lab, San Marino, CA 91108 USA. RP Gamero-Castano, M (reprint author), CALTECH, Jet Prop Lab, San Marino, CA 91108 USA. EM manuel.gamero@jpl.nasa.gov NR 7 TC 15 Z9 15 U1 0 U2 8 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD APR PY 2007 VL 78 IS 4 AR 043301 DI 10.1063/1.2721408 PG 7 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 162FZ UT WOS:000246073500007 PM 17477649 ER PT J AU Bar-Cohen, Y Kim, KJ Choi, HR Madden, JDW AF Bar-Cohen, Yoseph Kim, Kwang J. Choi, Hyouk Ryeol Madden, John D. W. TI Electroactive polymer materials SO SMART MATERIALS & STRUCTURES LA English DT Editorial Material C1 JPL, Pasadena, CA USA. Univ Nevada, Reno, NV 89557 USA. Sungkyunkwan Univ, Suwon, South Korea. Univ British Columbia, Vancouver, BC V5Z 1M9, Canada. RP Bar-Cohen, Y (reprint author), JPL, Pasadena, CA USA. RI Madden, John/B-8948-2009 OI Madden, John/0000-0002-0014-4712 NR 0 TC 2 Z9 2 U1 0 U2 9 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0964-1726 J9 SMART MATER STRUCT JI Smart Mater. Struct. PD APR PY 2007 VL 16 IS 2 DI 10.1088/0964-1726/16/2/E01 PG 2 WC Instruments & Instrumentation; Materials Science, Multidisciplinary SC Instruments & Instrumentation; Materials Science GA 145SZ UT WOS:000244886100001 ER PT J AU Song, GB Ma, N Lee, HJ AF Song, Gangbing Ma, Ning Lee, Ho-Jun TI Position estimation and control of SMA actuators based on electrical resistance measurement SO SMART STRUCTURES AND SYSTEMS LA English DT Article DE shape memory alloy; electric resistance; feedback control; sensorless feedback control AB As a functional material, shape memory alloy (SMA) has attracted much attention and research effort to explore its unique properties and its applications in the past few decades. Some of its properties, in particular the electrical resistance (ER) based self-sensing property of SMA, have not been fully studied. Electrical resistance of an SMA wire varies during its phase transformation. This variation is an inherent property of the SMA wire, although it is highly nonlinear with hysteresis. The relationship between the displacement and the electrical resistance of an SMA wire is deterministic and repeatable to some degree, therefore enabling the self-sensing ability of the SMA. The potential of this self-sensing ability has not received sufficient exploration so far, and even the previous studies in literature lack generality. This paper concerns the utilization of the self-sensing property of a spring-biased Nickel-Titanium (Nitinol) SMA actuator for two applications: ER feedback position control of an SMA actuator without a position sensor, and estimation of the opening of a SMA actuated valve. The use of the self-sensing property eliminates the need for a position sensor, therefore reducing the cost and size of an SMA actuator assembly. Two experimental apparatuses are fabricated to facilitate the two proposed applications, respectively. Based on open-loop testing results, the curve fitting technique is used to represent the nonlinear relationships between the displacement and the electrical resistance of the two SMA wire actuators. Using the mathematical models of the two SMA actuators, respectively, a proportional plus derivative controller is designed for control of the SMA wire actuator using only electrical resistance feedback. Consequently, the opening of the SMA actuated valve can be estimated without using an extra sensor. C1 Univ Houston, Dept Pharmaceut, Houston, TX 77030 USA. Cyrus Solut Corp, Conroe, TX USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Song, GB (reprint author), Univ Houston, Dept Pharmaceut, Houston, TX 77030 USA. EM gsong@uh.edu NR 7 TC 11 Z9 11 U1 2 U2 9 PU TECHNO-PRESS PI DAEJEON PA PO BOX 33, YUSEONG, DAEJEON 305-600, SOUTH KOREA SN 1738-1584 J9 SMART STRUCT SYST JI Smart. Struct. Syst. PD APR PY 2007 VL 3 IS 2 BP 189 EP 200 PG 12 WC Engineering, Civil; Engineering, Mechanical; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA 148HQ UT WOS:000245065700004 ER PT J AU Moran, TG Jennings, DE Deming, LD McCabe, GH Sada, PV Boyle, RJ AF Moran, Thomas G. Jennings, Donald E. Deming, L. Drake McCabe, George H. Sada, Pedro V. Boyle, Robert J. TI Solar magnetograms at 12 mu m using the Celeste spectrograph SO SOLAR PHYSICS LA English DT Article ID MICRON EMISSION-LINES; STOKES PROFILE ANALYSIS; VECTOR MAGNETIC-FIELDS; I 12-MU-M DIAGNOSTICS; INFRARED LINES; SUNSPOTS; FEATURES; PROBES AB We present the first solar vector magnetogram constructed from measurements of infra-red Mg I 12.32-mu m line spectra. Observations were made at the McMath-Pierce Telescope using the Celeste spectrometer/polarimeter. Zeeman-split Stokes line spectra were fitted with Seares profiles to obtain the magnetic field parameters. Maps of absolute field strength, line-of-sight angle, and azimuth are presented. Analysis shows that the variation in field strength within a spatial resolution element, 2 arcseconds, is greatest in the sunspot penumbra and that this is most likely caused by vertical field strength gradients, rather than horizontal image smearing. Widths of the Zeeman-split sigma components, assuming a formation layer thickness of 200 km, indicate that vertical field strength gradients can be as large as 6.5 G/km in a penumbra. C1 Catholic Univ Amer, Dept Phys, Washington, DC 20064 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. CMA Consulting Serv, Latham, NY 12110 USA. Univ Monterrey, Dept Fis & Matemat, Garza Garcia 66238, LL, Mexico. Dickinson Coll, Dept Phys & Astron, Carlisle, PA 17013 USA. RP Moran, TG (reprint author), Catholic Univ Amer, Dept Phys, Washington, DC 20064 USA. EM moran@esa.nascom.nasa.gov RI Jennings, Donald/D-7978-2012 NR 22 TC 6 Z9 6 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-0938 J9 SOL PHYS JI Sol. Phys. PD APR PY 2007 VL 241 IS 2 BP 213 EP 222 DI 10.1007/s11207-007-0271-1 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 181TE UT WOS:000247458200001 ER PT J AU Woo, R AF Woo, Richard TI Filamentary structures of coronal white-light images SO SOLAR PHYSICS LA English DT Article ID RADIO SCATTERING OBSERVATIONS; SOLAR-WIND; MAGNETIC-FIELDS; INTERPLANETARY SPACE; PHYSICAL-PROPERTIES; SCALE STRUCTURES; OUTER CORONA; FLOW; ACCELERATION; STREAMERS AB In the absence of magnetic field measurements of the solar corona, the density structure of white-light images has provided important insight into the coronal magnetic field. Recent work sparked by highly sensitive radio occultation measurements of path-integrated density has elucidated the density structure of unprocessed solar eclipse pictures. This paper does the same for processed images that reveal low-contrast small-scale structures, specifically Koutchmy's edge-enhanced white-light image of the 11 August 1999 solar eclipse. This processed image provides visual evidence for two important results deduced from radio occultation measurements of small-scale density variations. First, in addition to the closed loops readily seen at the base of the corona in high-resolution EUV and soft X-ray images, open filamentary structures permeate the corona including active regions generally thought to be magnetically closed. Observed at the image resolution, the filamentary structures are 1 degrees wide in latitude and an order of magnitude smaller than polar plumes. Second, although inhomogeneities that are convected along with the solar wind are also present, filamentary structures dominate the image because of their steeper density gradients. The quantitative profile of polarized brightness (pB) at the base of the corona shows that the filamentary structures have transverse density gradients that are proportional to their density. This explains why edge-enhanced images, limited in sensitivity to density gradients, tend to detect filamentary structures more readily in high-density regions (e.g., active regions, streamer stalks, and prominences) than in low-density polar coronal holes, and why filamentary structures seem more prevalent in solar eclipse pictures during solar maximum. The pB profile at the base of the corona also fills the gap in Doppler measurements there, reinforcing that open ultra-fine-scale filamentary structures observed by the radio measurements are predominantly radial and that they are an integral part of the radial expansion of the solar wind. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Woo, R (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 238-725, Pasadena, CA 91109 USA. EM richard.woo@jpl.nasa.gov NR 47 TC 6 Z9 6 U1 0 U2 1 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-0938 EI 1573-093X J9 SOL PHYS JI Sol. Phys. PD APR PY 2007 VL 241 IS 2 BP 251 EP 261 DI 10.1007/s11207-007-0250-6 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 181TE UT WOS:000247458200004 ER PT J AU Reiner, MJ Fainberg, J Kaiser, ML Bougeret, JL AF Reiner, M. J. Fainberg, J. Kaiser, M. L. Bougeret, J.-L. TI Circular polarization observed in interplanetary type III radio storms SO SOLAR PHYSICS LA English DT Article ID SOLAR-WIND SPEED; CORONAL MAGNETIC-FIELDS; CLUMPY LANGMUIR-WAVES; LOW-FREQUENCIES; ACTIVE REGIONS; PLASMA EMISSION; ELECTRON-BEAMS; NOISE STORMS; SHOCK-WAVES; NEAR-SUN AB We report the detection and analysis of circular polarization in solar type III radio storms at hectometric-to-kilometric wavelengths. We find that a small (usually less than 5%), but statistically significant, degree of circular polarization is present in all interplanetary type III radio storms below 1 MHz. The sense of the polarization, which is right-hand circular for some storms and left-hand circular for others, is maintained for the entire duration of the type III storm (usually many days). For a given storm, the degree of circular polarization peaks near central meridian crossing of the associated active region. At a given time, the degree of circular polarization is found to generally vary as the logarithm of the observing frequency. The radiation characteristics, including the polarization, for one interplanetary type III storm exhibits an unusual 1.6 hour oscillation. Based on the standard plasma emission theory of type III radiation, we discuss the implications of these observations for the magnitude and radial dependence of the solar magnetic field above active regions on the Sun. C1 Catholic Univ Amer, Greenbelt, MD 20770 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Observ Paris, Meudon, France. RP Reiner, MJ (reprint author), Catholic Univ Amer, Greenbelt, MD 20770 USA. EM michael.reiner@gsfc.nasa.gov NR 61 TC 11 Z9 12 U1 0 U2 1 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-0938 J9 SOL PHYS JI Sol. Phys. PD APR PY 2007 VL 241 IS 2 BP 351 EP 370 DI 10.1007/s11207-007-0277-8 PG 20 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 181TE UT WOS:000247458200011 ER PT J AU Kuzmin, RO Zabalueva, EV Mitrofanov, IG Litvak, ML Rodin, AV Boynton, WV Saunders, RS AF Kuzmin, R. O. Zabalueva, E. V. Mitrofanov, I. G. Litvak, M. L. Rodin, A. V. Boynton, W. V. Saunders, R. S. TI Seasonal redistribution of water in the surficial Martian regolith: Results from the Mars Odyssey high-energy neutron detector (HEND) SO SOLAR SYSTEM RESEARCH LA English DT Article ID GENERAL-CIRCULATION MODEL; NEAR-SURFACE; INSTRUMENT ONBOARD; MERIDIANI-PLANUM; ICE CLOUDS; GROUND ICE; VAPOR; CYCLE; ATMOSPHERE; BEHAVIOR AB The seasonal variation of neutron emissions from Mars in different spectral intervals measured by the HEND neutron detector for the entire Martian year are analyzed. Based on these data, the spatial variations of the neutron emissions from the planet are globally mapped as a function of season, and the dynamics of seasonal variation of neutron fluxes with different energies is analyzed in detail. No differences were found between seasonal regimes of neutron fluxes in different energy ranges in the southern hemisphere of Mars, while the regime of fast neutrons ( with higher energies) during the northern winter strongly differs from that during the southern winter. In winter (L-s = 270 degrees - 330 degrees), the fast neutron fluxes are noticeably reduced in the northern hemisphere ( along with the consecutive thickening of the seasonal cap of solid carbon dioxide). This provides evidence of a temporary increase in the water content in the effective layer of neutron generation. According to the obtained estimates, the observed reduction of the flux of fast neutrons in the effective layer corresponds to an increase in the water abundance of up to 5% in the seasonal polar cap (70 degrees - 90 degrees N), about 3% at mid-latitudes, and from 1.5 to 2% at low latitudes. The freezing out of atmospheric water at the planetary surface ( at middle and high latitudes) and the hydration of salt minerals composing the Martian soil are considered as the main processes responsible for the temporary increase in the water content in the soil and upper layer of the seasonal polar cap. The meridional atmospheric transport of water vapor from the summer southern to the winter northern hemisphere within the Hadley circulation cell is a basic process that delivers water to the subsurface soil layer and ensures the observed scale of the seasonal increase in water abundance. In the summer northern hemisphere, the similar Hadley circulation cell transports mainly dry air masses to the winter southern hemisphere. The point is that the water vapor becomes saturated at lower heights during aphelion, and the bulk of the atmospheric water mass is captured in the near-equatorial cloudy belt and, thus, is only weakly transferred to the southern hemisphere. This phenomenon, known as the Clancy effect, was suggested by Clancy et al. ( 1996) as a basic mechanism for the explanation of the interhemispheric asymmetry of water storage in permanent polar caps. The asymmetry of seasonal meridional circulation of the Martian atmosphere seems to be another factor determining the asymmetry of the seasonal water redistribution in the "atmosphere - regolith - seasonal polar caps" system, found in the peculiarities of the seasonal regime of the neutron emission of Mars. C1 Russian Acad Sci, Vernadsky Inst Geochem & Analyt Chem, Moscow 117975, Russia. Russian Acad Sci, Space Res Inst, Moscow 117810, Russia. Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. NASA Headquarters, Washington, DC 20514 USA. RP Kuzmin, RO (reprint author), Russian Acad Sci, Vernadsky Inst Geochem & Analyt Chem, Ul Kosygina 9, Moscow 117975, Russia. RI Rodin, Alexander/L-1904-2013 OI Rodin, Alexander/0000-0002-3601-7790 NR 47 TC 3 Z9 3 U1 0 U2 2 PU MAIK NAUKA/INTERPERIODICA/SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013-1578 USA SN 0038-0946 J9 SOLAR SYST RES+ JI Solar Syst. Res. PD APR PY 2007 VL 41 IS 2 BP 89 EP 102 DI 10.1134/S0038094607020013 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 160YG UT WOS:000245979800001 ER PT J AU Ji, Z Jalbout, AF Li, JQ AF Ji, Zhi Jalbout, A. F. Li, Jun-Qian TI Adsorption and diffusion of OH on Mo modified Pt(111) surface: First-principles theory SO SOLID STATE COMMUNICATIONS LA English DT Article DE OH; Pt(111) surface; density functional theory ID DENSITY-FUNCTIONAL THEORY; TOTAL-ENERGY CALCULATIONS; WAVE BASIS-SET; COADS+OHADS REACTION; H-2/CO MIXTURES; METAL-SURFACES; CO; ELECTROOXIDATION; ELECTRODES; PLATINUM AB A first-principles study of adsorption and diffusion of OH on Pt and PtMo (111) surfaces is described. It confirms that the dissociation of water is much easier on PtMo than on pure Pt. Furthermore, we also found that OH binds most strongly at Mo atop site with adsorption energy of -3.32 eV, which is similar to 1 eV stronger than binding to the pure Pt(111) surface. OH is much more localized on the PtMo alloy surface than on pure Pt. Both the stranger bond and the higher localization of OH contribute to the enhanced fuel cell performance with PtMo electrodes compared to pure Pt. (c) 2007 Elsevier Ltd. All rights reserved. C1 Fuzhou Univ, Dept Chem, Fujian 350002, Peoples R China. Univ Arizona, Dept Chem, NASA, Astrobiol Ctr Programme, Tucson, AZ 85711 USA. State Key Lab Struct Chem, Fuzhou 350002, Peoples R China. RP Li, JQ (reprint author), Fuzhou Univ, Dept Chem, Gongye Rd 523, Fujian 350002, Peoples R China. EM zhij2008@gmail.com NR 27 TC 11 Z9 11 U1 3 U2 15 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0038-1098 J9 SOLID STATE COMMUN JI Solid State Commun. PD APR PY 2007 VL 142 IS 3 BP 148 EP 153 DI 10.1016/j.ssc.2007.02.004 PG 6 WC Physics, Condensed Matter SC Physics GA 168GY UT WOS:000246512700006 ER PT J AU Nelson, RM Stevens, CM Stocky, JF AF Nelson, Robert M. Stevens, Christopher M. Stocky, John F. TI The deep space 1 mission: Flight validation of new technology SO SPACE SCIENCE REVIEWS LA English DT Editorial Material C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Nelson, RM (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM robert.m.nelson@jpl.nasa.gov NR 0 TC 0 Z9 0 U1 0 U2 1 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-6308 J9 SPACE SCI REV JI Space Sci. Rev. PD APR PY 2007 VL 129 IS 4 BP 305 EP 308 DI 10.1007/s11214-007-9164-8 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 202OZ UT WOS:000248914200001 ER PT J AU Rodgers, DH Beauchamp, PM Soderblom, LA Brown, RH Chen, GS Lee, M Sandel, BR Thomas, DA Benoit, RT Yelle, RV AF Rodgers, David H. Beauchamp, Patricia M. Soderblom, Laurence A. Brown, Robert H. Chen, Gun-Shing Lee, Meemong Sandel, Bill R. Thomas, David A. Benoit, Robert T. Yelle, Roger V. TI Advanced technologies demonstrated by the miniature integrated camera and spectrometer (MICAS) aboard deep space 1 SO SPACE SCIENCE REVIEWS LA English DT Review DE comet; asteroid; borrelly; braille; Mars; near-IR imaging spectrometer; UV imaging spectrometer; CCD camera; athermal optics; self-sequencing; silicon carbide; multifunction space instrument ID DEEP-SPACE-1 EXTENDED MISSION; COMET; SCIENCECRAFT; INSTRUMENT; NUCLEUS; PICS AB MICAS is an integrated multi-channel instrument that includes an ultraviolet imaging spectrometer (80-185 nm), two high-resolution visible imagers (10-20 mu rad/pixel, 400-900 nm), and a short-wavelength infrared imaging spectrometer (1250-2600 nm). The wavelength ranges were chosen to maximize the science data that could be collected using existing semiconductor technologies and avoiding the need for multi-octave spectrometers. It was flown on DS1 to validate technologies derived from the development of PICS (Planetary Imaging Camera Spectrometer). These technologies provided a novel systems approach enabling the miniaturization and integration of four instruments into one entity, spanning a wavelength range from the UV to IR, and from ambient to cryogenic temperatures with optical performance at a fraction of a wavelength. The specific technologies incorporated were: a built-in fly-by sequence; lightweight and ultra-stable, monolithic silicon-carbide construction, which enabled room-temperature alignment for cryogenic (85-140 K) performance, and provided superb optical performance and immunity to thermal distortion; diffraction-limited, shared optics operating from 80 to 2600 nm; advanced detector technologies for the UV, visible and short-wavelength IR; high-performance thermal radiators coupled directly to the short-wave infrared (SWIR) detector optical bench, providing an instrument with a mass less than 10 kg, instrument power less than 10 W, and total instrument cost of less than ten million dollars. The design allows the wavelength range to be extended by at least an octave at the short wavelength end and to similar to 50 microns at the long wavelength end. Testing of the completed instrument demonstrated excellent optical performance down to 77 K, which would enable a greatly reduced background for longer wavelength detectors. During the Deep Space 1 Mission, MICAS successfully collected images and spectra for asteroid 9969 Braille, Mars, and comet 19/P Borrelly. The Borrelly encounter was a scientific hallmark providing the first clear, high resolution images and excellent, short-wavelength infrared spectra of the surface of an active comet's nucleus. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91101 USA. US Geol Survey, Flagstaff, AZ 86001 USA. Univ Arizona, Tucson, AZ USA. Aerosp Corp, El Segundo, CA USA. SSG Inc, Wilmington, MA USA. RP Rodgers, DH (reprint author), CALTECH, Jet Prop Lab, Pasadena, CA 91101 USA. EM david.h.rodgers@jpl.nasa.gov NR 21 TC 1 Z9 1 U1 3 U2 4 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-6308 EI 1572-9672 J9 SPACE SCI REV JI Space Sci. Rev. PD APR PY 2007 VL 129 IS 4 BP 309 EP 326 DI 10.1007/s11214-007-9155-9 PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 202OZ UT WOS:000248914200002 ER PT J AU Young, DT Nordholt, JE Burch, JL McComas, DJ Bowman, RP Abeyta, RA Alexander, J Baldonado, J Barker, P Black, RK Booker, TL Casey, PJ Cope, L Crary, FJ Cravens, JP Funsten, HO Goldstein, R Guerrero, DR Hahn, F Hanley, J Henneke, BP Horton, EF Lawrence, DJ McCabe, KP Reisenfeld, D Salazar, RP Shappirio, M Storms, SA Urdiales, C Waite, JH AF Young, D. T. Nordholt, J. E. Burch, J. L. McComas, D. J. Bowman, R. P. Abeyta, R. A. Alexander, J. Baldonado, J. Barker, P. Black, R. K. Booker, T. L. Casey, P. J. Cope, L. Crary, F. J. Cravens, J. P. Funsten, H. O. Goldstein, R. Guerrero, D. R. Hahn, S. F. Hanley, J. Henneke, B. P. Horton, E. F. Lawrence, D. J. McCabe, K. P. Reisenfeld, D. Salazar, R. P. Shappirio, M. Storms, S. A. Urdiales, C. Waite, J. H., Jr. TI Plasma experiment for planetary exploration (PEPE) SO SPACE SCIENCE REVIEWS LA English DT Review DE mass spectrometry; plasma spectrometry; comets; comet 19P; borrelly ID ELECTROSTATIC ANALYZER; MASS-SPECTROMETER; ENERGY; DESIGN; FLIGHT; TIME; MAGNETOSPHERE; MISSION; SENSOR; FOILS AB The Plasma Experiment for Planetary Exploration (PEPE) flown on Deep Space 1 combines an ion mass spectrometer and an electron spectrometer in a single, low-resource instrument. Among its novel features PEPE incorporates an electrostatically swept field-of-view and a linear electric field time-of-flight mass spectrometer. A significant amount of effort went into developing six novel technologies that helped reduce instrument mass to 5.5 kg and average power to 9.6 W. PEPE's performance was demonstrated successfully by extensive measurements made in the solar wind and during the DS1 encounter with Comet 19P/Borrelly in September 2001. C1 SW Res Inst, San Antonio, TX 78238 USA. Los Alamos Natl Lab, Los Alamos, NM USA. Jet Propuls Lab, Pasadena, CA USA. Montana State Univ, Bozeman, MT 59717 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Young, DT (reprint author), SW Res Inst, San Antonio, TX 78238 USA. EM dyoung@swri.edu RI Funsten, Herbert/A-5702-2015; Reisenfeld, Daniel/F-7614-2015 OI Funsten, Herbert/0000-0002-6817-1039; NR 28 TC 9 Z9 9 U1 0 U2 1 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-6308 J9 SPACE SCI REV JI Space Sci. Rev. PD APR PY 2007 VL 129 IS 4 BP 327 EP 357 DI 10.1007/s11214-007-9177-3 PG 31 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 202OZ UT WOS:000248914200003 ER PT J AU Chin, G Brylow, S Foote, M Garvin, J Kasper, J Keller, J Litvak, M Mitrofanov, I Paige, D Raney, K Robinson, M Sanin, A Smith, D Spence, H Spudis, P Stern, SA Zuber, M AF Chin, Gordon Brylow, Scott Foote, Marc Garvin, James Kasper, Justin Keller, John Litvak, Maxim Mitrofanov, Igor Paige, David Raney, Keith Robinson, Mark Sanin, Anton Smith, David Spence, Harlan Spudis, Paul Stern, S. Alan Zuber, Maria TI Lunar reconnaissance orbiter overview: The instrument suite and mission SO SPACE SCIENCE REVIEWS LA English DT Review DE moon; lunar; Vision for Space Exploration; NASA; spacecraft; space instrumentation; remote observation ID MARS; ICE AB NASA's Lunar Precursor Robotic Program (LPRP), formulated in response to the President's Vision for Space Exploration, will execute a series of robotic missions that will pave the way for eventual permanent human presence on the Moon. The Lunar Reconnaissance Orbiter (LRO) is first in this series of LPRP missions, and plans to launch in October of 2008 for at least one year of operation. LRO will employ six individual instruments to produce accurate maps and high-resolution images of future landing sites, to assess potential lunar resources, and to characterize the radiation environment. LRO will also test the feasibility of one advanced technology demonstration package. The LRO payload includes: Lunar Orbiter Laser Altimeter (LOLA) which will determine the global topography of the lunar surface at high resolution, measure landing site slopes, surface roughness, and search for possible polar surface ice in shadowed regions, Lunar Reconnaissance Orbiter Camera (LROC) which will acquire targeted narrow angle images of the lunar surface capable of resolving meter-scale features to support landing site selection, as well as wide-angle images to characterize polar illumination conditions and to identify potential resources, Lunar Exploration Neutron Detector (LEND) which will map the flux of neutrons from the lunar surface to search for evidence of water ice, and will provide space radiation environment measurements that may be useful for future human exploration, Diviner Lunar Radiometer Experiment (DLRE) which will chart the temperature of the entire lunar surface at approximately 300 meter horizontal resolution to identify cold-traps and potential ice deposits, Lyman-Alpha Mapping Project (LAMP) which will map the entire lunar surface in the far ultraviolet. LAMP will search for surface ice and frost in the polar regions and provide images of permanently shadowed regions illuminated only by starlight. Cosmic Ray Telescope for the Effects of Radiation (CRaTER), which will investigate the effect of galactic cosmic rays on tissue-equivalent plastics as a constraint on models of biological response to background space radiation. The technology demonstration is an advanced radar (mini-RF) that will demonstrate X- and S-band radar imaging and interferometry using light weight synthetic aperture radar. This paper will give an introduction to each of these instruments and an overview of their objectives. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Malin Space Sci Syst, San Diego, CA 92121 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. MIT, Cambridge, MA 02139 USA. Russian Fed Space Agcy, Space Res Inst, Moscow 117997, Russia. Johns Hopkins Univ, Appl Phys Lab, Laurel, MD 20723 USA. Arizona State Univ, Tempe, AZ 85287 USA. Boston Univ, Boston, MA 02215 USA. SW Res Inst, Boulder, CO 80302 USA. Univ Calif Los Angeles, Los Angeles, CA 90095 USA. RP Chin, G (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. EM gordon.chin-1@nasa.gov RI Chin, Gordon/E-1520-2012; Kasper, Justin/D-1152-2010; Spence, Harlan/A-1942-2011; Keller, John/I-5097-2013; OI Kasper, Justin/0000-0002-7077-930X; Spence, Harlan/0000-0002-2526-2205 NR 24 TC 145 Z9 151 U1 20 U2 44 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-6308 J9 SPACE SCI REV JI Space Sci. Rev. PD APR PY 2007 VL 129 IS 4 BP 391 EP 419 DI 10.1007/s11214-007-9153-y PG 29 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 202OZ UT WOS:000248914200005 ER PT J AU Campbell, JE Carmichael, GR Tang, Y Chai, T Vay, SA Choi, YH Sachse, GW Singh, HB Schnoor, JL Woo, J Vukovich, JM Streets, DG Huey, LG Stanier, CO AF Campbell, J. E. Carmichael, G. R. Tang, Y. Chai, T. Vay, S. A. Choi, Y. -H. Sachse, G. W. Singh, H. B. Schnoor, J. L. Woo, J. Vukovich, J. M. Streets, D. G. Huey, L. G. Stanier, C. O. TI Analysis of anthropogenic CO2 signal in ICARTT using a regional chemical transport model and observed tracers SO TELLUS SERIES B-CHEMICAL AND PHYSICAL METEOROLOGY LA English DT Article; Proceedings Paper CT 7th International Conference on Carbon Dioxide Utilization CT 7th International Carbon Dioxide Conference (CO2) CY OCT 12-16, 2003 CY SEP 25-30, 2005 CL Seoul, SOUTH KOREA CL Boulder, CO SP Korea Res Inst Chem Technol, Carbon Dioxide Reduct & Sequestrat R&D Ctr, Minist Sci & Technol Korea, Res Inst Innovat Technol Earth, New Energy & Ind Technol Dev Org Japan SP NOAA ID VOLATILE ORGANIC-COMPOUNDS; CARBON-DIOXIDE FLUXES; ATMOSPHERIC CO2; SENSITIVITY; EMISSIONS; PACIFIC; INVERSION; TOWER; SINKS AB Atmospheric CO2 inversion studies infer surface sources and sinks from observations and models. These studies usually require determination of the fossil fuel component of the observation, which can be estimated using anthropogenic tracers such as CO. The objective of this study is to demonstrate a new CO tracer method that accounts for overlapping forest fire and photochemical CO influences, and to quantify several aspects of the uncertainty in the CO tracer technique. Photochemistry model results and observations from the International Consortium for Atmospheric Research on Transport and Transformation experiment are used to quantify changes in the fossil fuel CO2 prediction from the CO tracer method with and without the inclusion of CO from biomass burning and photochemistry. Although the chemical sources and sinks tend to offset each other, there are regions where the chemical reactions change fossil fuel CO2 predictions by up to +/- 4 ppm. Including biomass burning lowers fossil fuel CO2 by an average of 12 ppm in plumes heavily influenced by long-range transport of forest fire CO. An alternate fossil fuel CO2 calculation is done in a power plant plume using SO2 as a tracer, giving a change in 20 ppm from the CO method, indicative of uncertainty in the assumed CO:CO2 ratio. C1 Univ Iowa, Ctr Global & Reg Environm Res, Iowa City, IA 52242 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NE States Coordinated Air Use Management, Boston, MA 02114 USA. Univ N Carolina, Carolina Environm Program, Chapel Hill, NC 27599 USA. Argonne Natl Lab, Decis & Informat Sci Div, Argonne, IL 60439 USA. Georgia Inst Technol, Sch Earth & Atmospher Sci, Atlanta, GA 30332 USA. RP Campbell, JE (reprint author), Univ Iowa, Ctr Global & Reg Environm Res, Iowa City, IA 52242 USA. EM cae@engineering.uiowa.edu RI Campbell, Elliott/B-8025-2008; Chai, Tianfeng/E-5577-2010; Stanier, Charles/D-4307-2016; Tang, Youhua/D-5205-2016; OI Chai, Tianfeng/0000-0003-3520-2641; Stanier, Charles/0000-0001-9924-0853; Tang, Youhua/0000-0001-7089-7915; Streets, David/0000-0002-0223-1350 NR 46 TC 7 Z9 8 U1 0 U2 4 PU TAYLOR & FRANCIS LTD PI ABINGDON PA 2-4 PARK SQUARE, MILTON PARK, ABINGDON OR14 4RN, OXON, ENGLAND SN 1600-0889 J9 TELLUS B JI Tellus Ser. B-Chem. Phys. Meteorol. PD APR PY 2007 VL 59 IS 2 BP 199 EP 210 DI 10.1111/j.1600-0889.2006.00239.x PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 156DS UT WOS:000245628900005 ER PT J AU Potter, C Kumar, V Klooster, S Nemani, R AF Potter, Christopher Kumar, Vipin Klooster, Steven Nemani, Ramakrishna TI Recent history of trends in vegetation greenness and large-scale ecosystem disturbances in Eurasia SO TELLUS SERIES B-CHEMICAL AND PHYSICAL METEOROLOGY LA English DT Article ID LEAF-AREA INDEX; LAND-USE CHANGE; SATELLITE DATA; TERRESTRIAL ECOSYSTEMS; FOREST-FIRES; CARBON; EMISSIONS; BIOMASS; TEMPERATURES; COVER AB Recent patterns of land cover and vegetation dynamics on the Euasian continent have been linked to changes in the global carbon cycle. Our study was conducted to evaluate patterns in a 19-yr record of global satellite observations of terrestrial vegetation from the Advanced Very High Resolution Radiometer (AVHRR) as a means to characterize major trends in both vegetation 'greenness' and ecosystem disturbance. The fraction absorbed of photosynthetically active radiation (FPAR) by vegetation canopies worldwide has been computed from the AVHRR at a monthly time interval from 1982 to 2000 and gridded at a spatial resolution of 8 km globally. Unlike previous studies of the AVHRR multiyear time-series of vegetation dynamics, the 8-km spatial resolution makes it possible to compare disturbance events and greenness trends at the same level of spatial detail. Positive trends in FPAR were detected throughout a major greenbelt of central-eastern Europe starting in the mid-1980s. This Eurasian greenbelt extended in a wide swath over the Urals, into the vicinity of Lake Baykal south of the central Siberian plateau, mainly along a latitude belt from 55 degrees N to 65 degrees N. There was also significantly positive greening in relatively large areas of Great Britain, Italy, Greece, Turkey, the Caucasus and southern India. Nonetheless, a strong downward trend in the FPAR time-series over most of Eurasia was observed by the end of the 1990s. Throughout the 19-yr time period, Eurasia was also impacted by many notable droughts and other disturbance events that could have substantially offset decadal carbon gains attributed to satellite-observed greening. Large-scale ecosystems disturbance events were identified in the FPAR time-series by locating anomalously low values (FPAR-LO) that lasted longer than 12 consecutive months at any 8-km pixel. We find verifiable evidence of numerous disturbance types across Eurasia, including regional patterns of severe droughts, forest fires and insect outbreaks. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ Minnesota, Minneapolis, MN USA. Calif State Univ Monterey Bay, Seaside, CA USA. RP Potter, C (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. EM cpotter@mail.arc.nasa.gov NR 50 TC 12 Z9 14 U1 1 U2 6 PU BLACKWELL PUBLISHING PI OXFORD PA 9600 GARSINGTON RD, OXFORD OX4 2DQ, OXON, ENGLAND SN 0280-6509 J9 TELLUS B JI Tellus Ser. B-Chem. Phys. Meteorol. PD APR PY 2007 VL 59 IS 2 BP 260 EP 272 DI 10.1111/j.1600-0889.2006.00245.x PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 156DS UT WOS:000245628900011 ER PT J AU Curreri, PA AF Curreri, Peter A. TI Processing Space Resource to Enable the "Vision for Space Exploration" SO TRANSACTIONS OF THE INDIAN INSTITUTE OF METALS LA English DT Article AB The NASA human exploration program as directed by the "Vision for Exploration" (G. W. Bush, Jan. 14, 2004) includes developing methods for in situ processing the materials of the Moon, Mars and beyond to enable safe and affordable human exploration of the solar system. Recent advances in materials technologies could make it possible to achieve mass, energy, and life support self sufficiency at far lower costs than were projected during NASA studies in the 1970s. If the "Exploration Vision" program is executed with an emphasis on the utilization of space resources, it could provide a path for human self reliance beyond Earth orbit This path can lead to an open, non-zero-sum, future for humanity with safer human competition and with limitless potential for growth. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Curreri, PA (reprint author), NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. EM Peter.A.Curreri@nasa.gov NR 18 TC 0 Z9 0 U1 0 U2 1 PU SPRINGER INDIA PI NEW DELHI PA 7TH FLOOR, VIJAYA BUILDING, 17, BARAKHAMBA ROAD, NEW DELHI, 110 001, INDIA SN 0972-2815 J9 T INDIAN I METALS JI Trans. Indian Inst. Met. PD APR-JUN PY 2007 VL 60 IS 2-3 SI SI BP 99 EP 102 PG 4 WC Metallurgy & Metallurgical Engineering SC Metallurgy & Metallurgical Engineering GA V23DR UT WOS:000208324000007 ER PT J AU Ray, CS Ramachandran, N Sen, S AF Ray, C. S. Ramachandran, N. Sen, S. TI An Analysis of the Differences in the Glass Forming Tendency of Melts on Earth and in a Low-Gravity Environment SO TRANSACTIONS OF THE INDIAN INSTITUTE OF METALS LA English DT Article AB Experiments conducted up to this time on glass forming melts in the low gravity environment of space show that glasses prepared in low gravity are more chemically homogeneous and more resistant to crystallization than comparable glasses prepared on Earth. This result is somewhat in contradiction to the accepted concept of glass formation for a melt A hypothesis based on "shear thinning" of a melt, a decrease in viscosity with increasing shear stress, is proposed as an explanation for the observed low-gravity results. This paper describes results from numerical simulations to test the role of natural convection in introducing shear stress in glass forming melts, using a Li2O-2SiO(2) melt as a model. The simulation system in its idealized version consists of a cylinder that is subjected to a longitudinal temperature gradient with the gravity vector oriented perpendicular to the temperature gradient. The governing equations of motion and energy are solved in primitive variables and the parametric influence of the gravity level on the buoyancy induced convection in the melt is calculated. The shear stress in the system is then computed as a function of the gravity level and its possible influence on affecting the melt viscosity (shear thinning) is then assessed. C1 [Ray, C. S.; Ramachandran, N.; Sen, S.] NASA, George C Marshall Space Flight Ctr, BAE Syst, Huntsville, AL 35812 USA. RP Ray, CS (reprint author), NASA, George C Marshall Space Flight Ctr, BAE Syst, Huntsville, AL 35812 USA. EM Subhayu.Sen-1@nasa.gov NR 17 TC 0 Z9 0 U1 0 U2 2 PU SPRINGER INDIA PI NEW DELHI PA 7TH FLOOR, VIJAYA BUILDING, 17, BARAKHAMBA ROAD, NEW DELHI, 110 001, INDIA SN 0972-2815 J9 T INDIAN I METALS JI Trans. Indian Inst. Met. PD APR-JUN PY 2007 VL 60 IS 2-3 SI SI BP 143 EP 147 PG 5 WC Metallurgy & Metallurgical Engineering SC Metallurgy & Metallurgical Engineering GA V23DR UT WOS:000208324000015 ER PT J AU Murty, BS Sen, S Stefanescu, DM AF Murty, B. S. Sen, S. Stefanescu, D. M. TI Special issue on solidification science and processing PREFACE SO TRANSACTIONS OF THE INDIAN INSTITUTE OF METALS LA English DT Editorial Material C1 [Murty, B. S.] IIT Madras, Madras, Tamil Nadu, India. [Sen, S.] NASA, BAE SYS Marshall Space Flight Ctr, Huntsville, AL USA. [Stefanescu, D. M.] Ohio State Univ, Columbus, OH 43210 USA. RP Murty, BS (reprint author), IIT Madras, Madras, Tamil Nadu, India. RI Stefanescu, Doru/G-8101-2012; Murty, BS/P-3354-2015 NR 0 TC 0 Z9 0 U1 0 U2 1 PU SPRINGER INDIA PI NEW DELHI PA 7TH FLOOR, VIJAYA BUILDING, 17, BARAKHAMBA ROAD, NEW DELHI, 110 001, INDIA SN 0972-2815 J9 T INDIAN I METALS JI Trans. Indian Inst. Met. PD APR-JUN PY 2007 VL 60 IS 2-3 SI SI PG 1 WC Metallurgy & Metallurgical Engineering SC Metallurgy & Metallurgical Engineering GA V23DR UT WOS:000208324000001 ER PT J AU DellaCorte, C AF DellaCorte, Christopher TI Tribology legends - heroes or villains? SO TRIBOLOGY & LUBRICATION TECHNOLOGY LA English DT Editorial Material C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP DellaCorte, C (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. EM cdellacorte@stle.org NR 0 TC 0 Z9 0 U1 0 U2 0 PU SOC TRIBOLOGISTS & LUBRICATION ENGINEERS PI PARK RIDGE PA 840 BUSSE HIGHWAY, PARK RIDGE, IL 60068 USA SN 1545-858X J9 TRIBOL LUBR TECHNOL JI Tribol. Lubr. Technol. PD APR PY 2007 VL 63 IS 4 BP 6 EP 6 PG 1 WC Engineering, Mechanical SC Engineering GA 155XY UT WOS:000245613300002 ER PT J AU Thomas, BC Jackman, CH Melott, AL AF Thomas, B. C. Jackman, C. H. Melott, A. L. TI Modeling atmospheric effects of the September 1859 solar flare SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID COSMIC-RAY EVENTS; PROTON-EVENTS; MIDDLE-ATMOSPHERE; 2-DIMENSIONAL MODEL; STRATOSPHERIC OZONE; NITRIC-OXIDE; RADIATION; DEPLETION; ICE AB We have modeled atmospheric effects, especially ozone depletion, due to a solar proton event which probably accompanied the extreme magnetic storm of 1-2 September 1859. We use an inferred proton fluence for this event as estimated from nitrate levels in Greenland ice cores. We present results showing production of odd nitrogen compounds and their impact on ozone. We also compute rainout of nitrate in our model and compare to values from ice core data. C1 Washburn Univ, Dept Phys & Astron, Topeka, KS 66621 USA. NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. Univ Kansas, Dept Phys & Astron, Lawrence, KS 66045 USA. RP Thomas, BC (reprint author), Washburn Univ, Dept Phys & Astron, 1700 SW Coll Ave, Topeka, KS 66621 USA. EM brian.thomas@washburn.edu RI Jackman, Charles/D-4699-2012; OI Thomas, Brian/0000-0001-9091-0830 NR 34 TC 30 Z9 30 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD MAR 31 PY 2007 VL 34 IS 6 AR L06810 DI 10.1029/2006GL029174 PG 5 WC Geosciences, Multidisciplinary SC Geology GA 155BO UT WOS:000245552900006 ER PT J AU Schroder, TM Ao, CO Juarez, MD AF Schroder, Thomas M. Ao, Chi O. Juarez, Manuel de la Torre TI Sensitivity of GPS occultation to the stratopause height SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID NEUTRAL ATMOSPHERE; MIDDLE-ATMOSPHERE; ERROR ANALYSIS; TEMPERATURE; VALIDATION; INVERSION; QUALITY; SYSTEM; RECORD; BIASES AB We scrutinize temperature profiles collected with radio occultation measurement for an imprint of the stratopause. In the retrieval step that integrates bending angle data to atmospheric refractivity, the falloff toward infinite altitude is constrained in a boundary condition with statistical optimization or extrapolation. We point to the coherence between temperature and density scale height as advocator for a fitting procedure that exploits data down to the stratopause. Data below have higher signal-to-noise ratio, but fitting them in costs additional parameters for the shifted sign in scale height gradient. On the basis of noise free simulation using a climatology covering all latitudes, seasons, and hours and on the basis of validation against data collected with weather balloons, laser imaging, and limb sounding, we find that adaptation to the fluctuating stratopause is crucial for the accuracy of the retrieved temperature. To facilitate investigation, the stratopause altitude was preset in the boundary condition according to climatological temperature. Biases between 10 and 50 hPa cancel out when the fitting interval is extended to 7.2 km above the stratopause, almost the average displacement of the maximum density scale height caused by nonlinearity in the temperature profile. This is a reminder that the stratopause should be read from bending angle, not temperature. Moreover, bias would be approaching zero at all levels if the a priori information for extrapolation had been lapse rate, not isothermal conditions. Keeping the model seed for temperature conversion to subsequent retrieval steps eliminates external information from the deconvolved refractivity. It will help argue for radio occultation as independent vehicle for climate monitoring. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Schroder, TM (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM tms@jpl.nasa.gov; chi.o.ao@jpl.nasa.gov; mtj@jpl.nasa.gov NR 38 TC 3 Z9 3 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAR 31 PY 2007 VL 112 IS D6 AR D06119 DI 10.1029/2006JD007330 PG 10 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 155BW UT WOS:000245553800003 ER PT J AU Zheng, Q Susanto, RD Ho, CR Song, YT Xu, Q AF Zheng, Quanan Susanto, R. Dwi Ho, Chung-Ru Song, Y. Tony Xu, Qing TI Statistical and dynamical analyses of generation mechanisms of solitary internal waves in the northern South China Sea SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID SPACE-SHUTTLE PHOTOGRAPHS; PACIFIC-OCEAN; THERMOCLINE; SOLITONS; PROPAGATION; EVOLUTION; FISSION; WATER AB [1] This study analyzes the effects of thermocline shoaling on the ocean internal wave (IW) generation in the north South China Sea (NSCS). Seven years of satellite synthetic aperture radar (SAR) images from 1995 to 2001 are used for the statistical analysis of IW occurrence, and field measurements of sea surface wind, sea state, and vertical temperature profiles are used for analyzing IW generation and SAR imaging conditions. Latitudinal distribution of IW packets shows that 22% of IW packets distributed in the east of 118 degrees E obviously originate from the Luzon Strait, and 78% of IW packets west of 118 degrees E may propagate from the east or evolve into the solitons originating from the east boundary owing to the fission effect of shoaling thermocline. The yearly distribution of IW occurrence frequencies reveals an interannual variability, implying that there are long-term and large-scale processes modifying the SAR-observed IW occurrence. The monthly SAR-observed IW occurrence frequencies show that the high frequencies are distributed from April to July and reach a peak in June with a maximum frequency of 20%. The low occurrence frequencies are distributed in winter from December to February of next year with a minimum frequency of 1.5% in February. This study proposes that the IW generation needs the necessary and sufficient conditions: initial disturbance formation and wave amplitude growth. Owing to the dissipation effect on the initial disturbance, only fully grown waves have a chance to radiate out of the source region. A physical model and PKdV equation are adopted for analyzing the sufficient conditions for solitary IW amplitude growth. The results indicate that the thermocline shoaling provides the forcing to soliton amplitude growth, so that the soliton amplitude growth ratio (SAGR) serves as a decisive factor for the IW occurrence frequency. Theoretical analysis predicts a linear relation between the two. Application of theoretical models to field measurements in the Luzon Strait gives a correlation coefficient as high as 0.845 with a confidence level of 99% for months from March to November. The linear regression gives a correlation coefficient (R-2) of 0.6519 and a SAGR threshold ( minimum) value of 0.90 for IW occurrence. According to the theoretical solutions, the eastward propagating disturbances have no chance to grow up, so that they hardly appear on the east side of the submarine ridges in the eastern Luzon Strait. C1 Univ Maryland, Dept Atmospher & Ocean Sci, College Pk, MD 20742 USA. Columbia Univ, Lamont Doherty Earth Observ, Palisades, NY 10964 USA. Natl Taiwan Ocean Univ, Dept Marine Environm Informat, Chilung 202, Taiwan. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Zheng, Q (reprint author), Univ Maryland, Dept Atmospher & Ocean Sci, 2423 Comp Space Sci Bldg, College Pk, MD 20742 USA. EM quanan@atmos.umd.edu; dwi@ldeo.columbia.edu; chungru@sun4.oce.ntou.edu.tw; song@pacific.jpl.nasa.gov; gingxu@atmos.umd.edu RI Zheng, Quanan/F-9025-2010; OI SUSANTO, Raden Dwi/0000-0003-1495-5951 NR 31 TC 74 Z9 84 U1 5 U2 36 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-OCEANS JI J. Geophys. Res.-Oceans PD MAR 30 PY 2007 VL 112 IS C3 AR C03021 DI 10.1029/2006JC003551 PG 16 WC Oceanography SC Oceanography GA 155CG UT WOS:000245554800002 ER PT J AU Elkins-Tanton, LT Smrekar, SE Hess, PC Parmentier, EM AF Elkins-Tanton, L. T. Smrekar, S. E. Hess, P. C. Parmentier, E. M. TI Volcanism and volatile recycling on a one-plate planet: Applications to Venus SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Review ID STEEP-SIDED DOMES; NOMINALLY ANHYDROUS MINERALS; STAGNANT LID CONVECTION; SOUTHERN SIERRA-NEVADA; OF-SIGHT ACCELERATIONS; MIDOCEAN RIDGE BASALTS; PHASE-RELATIONS; CORONA FORMATION; MAGELLAN DATA; NATURAL PERIDOTITE AB The surface of Venus displays volcanic features indicating eruption of lavas with a wide range of viscosities. We present numerical experiments showing that lithospheric gravitational instabilities can produce lavas with compositions consistent with the range of volcanic forms seen on Venus. The presence of incompatible elements and their oxides (specifically, water, carbon dioxide, and alkali elements) in trace- to percent-level concentrations in the Venusian mantle allows the formation of a variety of magmatic source regions. The pressure and temperature paths that the dense lithospheric materials travel as they sink into the Venusian mantle indicate that the lithospheric material may devolatilize as it sinks, enriching the surrounding upper mantle, or it may itself melt. These processes can produce magmas with a variety of compositions and viscosities, potentially consistent with the range of Venusian volcanic forms. These processes also suggest that Venus may recycle incompatible elements internally. Indeed, if Venus began with an internal volatile content, then no amount of partial melting can make it entirely volatile-free even in the absence of recycling into the interior. These models therefore suggest geodynamic processes that can produce a range of magmatic activity and retain some interior volatiles on a one-plate planet. C1 Brown Univ, Dept Geol Sci, Providence, RI 02912 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Elkins-Tanton, LT (reprint author), MIT, Dept Earth Atmospher & Planetary Sci, 77 Massachusetts Ave, Cambridge, MA 02139 USA. EM ltelkins@mit.edu RI Elkins-Tanton, Linda/C-5508-2008 OI Elkins-Tanton, Linda/0000-0003-4008-1098 NR 120 TC 11 Z9 11 U1 0 U2 16 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD MAR 30 PY 2007 VL 112 IS E4 AR E04S06 DI 10.1029/2006JE002793 PG 15 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 155CN UT WOS:000245555500001 ER PT J AU Cozmuta, I Blanco, M Goddard, WA AF Cozmuta, Ioana Blanco, Mario Goddard, William A., III TI Gas sorption and barrier properties of polymeric membranes from molecular dynamics and Monte Carlo simulations SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID POLYPROPYLENE; POLYETHYLENE; PERMEATION; SOLUBILITY; DIFFUSION AB It is important for many industrial processes to design new materials with improved selective permeability properties. Besides diffusion, the molecule's solubility contributes largely to the overall permeation process. This study presents a method to calculate solubility coefficients of gases such as O-2, H2O (vapor), N-2, and CO2 in polymeric matrices from simulation methods (Molecular Dynamics and Monte Carlo) using first principle predictions. The generation and equilibration (annealing) of five polymer models (polypropylene, polyvinyl alcohol, polyvinyl dichloride, polyvinyl chloride-trifluoroethylene, and polyethylene terephtalate) are extensively described. For each polymer, the average density and Hansen solubilities over a set of ten samples compare well with experimental data. For polyethylene terephtalate, the average properties between a small (n = 10) and a large (n = 100) set are compared. Boltzmann averages and probability density distributions of binding and strain energies indicate that the smaller set is biased in sampling configurations with higher energies. However, the sample with the lowest cohesive energy density from the smaller set is representative of the average of the larger set. Density-wise, low molecular weight polymers tend to have on average lower densities. Infinite molecular weight samples do however provide a very good representation of the experimental density. Solubility constants calculated with two ensembles (grand canonical and Henry's constant) are equivalent within 20%. For each polymer sample, the solubility constant is then calculated using the faster (10x) Henry's constant ensemble (HCE) from 150 ps of NPT dynamics of the polymer matrix. The influence of various factors (bad contact fraction, number of iterations) on the accuracy of Henry's constant is discussed. To validate the calculations against experimental results, the solubilities of nitrogen and carbon dioxide in polypropylene are examined over a range of temperatures between 250 and 650 K. The magnitudes of the calculated solubilities agree well with experimental results, and the trends with temperature are predicted correctly. The HCE method is used to predict the solubility constants at 298 K of water vapor and oxygen. The water vapor solubilities follow more closely the experimental trend of permeabilities, both ranging over 4 orders of magnitude. For oxygen, the calculated values do not follow entirely the experimental trend of permeabilities, most probably because at this temperature some of the polymers are in the glassy regime and thus are diffusion dominated. Our study also concludes large confidence limits are associated with the calculated Henry's constants. By investigating several factors (terminal ends of the polymer chains, void distribution, etc.), we conclude that the large confidence limits are intimately related to the polymer's conformational changes caused by thermal fluctuations and have to be regardedat least at microscaleas a characteristic of each polymer and the nature of its interaction with the solute. Reducing the mobility of the polymer matrix as well as controlling the distribution of the free (occupiable) volume would act as mechanisms toward lowering both the gas solubility and the diffusion coefficients. C1 ELORET Corp, NASA Ames Res Ctr, Moffett Field, CA 94035 USA. CALTECH, Pasadena, CA 91125 USA. RP Goddard, WA (reprint author), CALTECH, Mat & Proc Simulat Ctr, Mail Code B1 139-74, Pasadena, CA 91125 USA. EM wag@wag.caltech.edu NR 25 TC 28 Z9 28 U1 4 U2 44 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1520-6106 J9 J PHYS CHEM B JI J. Phys. Chem. B PD MAR 29 PY 2007 VL 111 IS 12 BP 3151 EP 3166 DI 10.1021/jp062942h PG 16 WC Chemistry, Physical SC Chemistry GA 148OE UT WOS:000245083700012 PM 17388466 ER PT J AU Ao, CO AF Ao, C. O. TI Effect of ducting on radio occultation measurements: An assessment based on high-resolution radiosonde soundings SO RADIO SCIENCE LA English DT Article ID LOWER TROPOSPHERE; SIGNALS; REFRACTIVITY; SUPERREFRACTION; INVERSION AB [1] Recent studies have shown that the presence of elevated ducts in the lower atmosphere has an adverse effect on the inversion of GPS radio occultation data. The problem arises because the microwave refractivity within and below an elevated duct is no longer uniquely determined by the bending angle profile. Applying Abel inversion without a priori knowledge of the duct will introduce a negative bias in the retrieved refractivity profile within and below the duct. In this work, high vertical resolution radiosonde data are used to give a quantitative assessment of the characteristics and effects of ducts, including their frequency of occurrences, heights, and thicknesses at different latitudes and seasons. The negative bias from the Abel-retrieved refractivity profiles resulting from these ducts is also computed. The results give a strong indication that ducting in the lower troposphere is a frequent phenomenon over the tropics and midlatitudes. The ducts are shown to be predominantly caused by sharp changes in the vertical structure of water vapor. The majority of the ducts are found to be below 2 km, with a median duct layer thickness of about 100 m. The negative refractivity bias is shown to be largest below 2 km, with a median value of about 0.5 - 1% in the tropics and 0.2 - 0.5% in midlatitudes. The bias is about a factor of 2 - 3 smaller between 2 to 3 km and is negligible above 4 km. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Ao, CO (reprint author), CALTECH, Jet Prop Lab, M-S 138-308,4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM chi.o.ao@jpl.nasa.gov NR 24 TC 19 Z9 19 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0048-6604 EI 1944-799X J9 RADIO SCI JI Radio Sci. PD MAR 28 PY 2007 VL 42 IS 2 AR RS2008 DI 10.1029/2006RS003485 PG 15 WC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications SC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications GA 155CU UT WOS:000245556200001 ER PT J AU Farrell, WM Kaiser, ML Fischer, G Zarka, P Kurth, WS Gurnett, DA AF Farrell, W. M. Kaiser, M. L. Fischer, G. Zarka, P. Kurth, W. S. Gurnett, D. A. TI Are Saturn electrostatic discharges really superbolts? A temporal dilemma SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID RADIO; ATMOSPHERE; RADIATION; JUPITER AB Saturn electrostatic discharges ( SED) are freely-propagating radio emissions detected in the high frequency (HF) radio band (1-40 MHz) associated with electrical discharge (i.e., lightning) from storms in Saturn's atmosphere. While SEDs responsible for the RF emission are considered to be very energetic superbolts (>10(13) J), this determination is intimately related to the temporal nature of the discharge itself. As we demonstrate, if we assume the discharge has similar temporal properties as terrestrial cloud-to-ground discharges ( with a stroke time scale similar to 70 mu s), then indeed the discharge energy has to be similar to 10(13) J in order account for the Cassini-observed radiated HF power of similar to 50 W/Hz. However, if the discharge duration is faster than the terrestrial case (i.e., similar to 1 mu s), the energy of the discharge can be weaker than the terrestrial case since the central peak of the emission shifts closer to the HF band. Because of the near-flat SED spectra measured in the HF which favors a faster discharge, we conclude that the high level of radiated HF power from SEDs may have less to do with any extreme super-bolt strength of the discharge and has more to do with the intrinsic quick time-scale of relatively weaker discharges. C1 NASA, Goddard Space Flight Ctr, Sci Explorate Directorate, Greenbelt, MD 20771 USA. Univ Iowa, Dept Phys & Astron, Iowa City, IA 52242 USA. CNRS, Observ Paris, LESIA, F-92195 Meudon, France. RP Farrell, WM (reprint author), NASA, Goddard Space Flight Ctr, Sci Explorate Directorate, Greenbelt, MD 20771 USA. EM william.farrell@gsfc.nasa.gov RI Farrell, William/I-4865-2013; OI Kurth, William/0000-0002-5471-6202 NR 23 TC 10 Z9 10 U1 1 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD MAR 27 PY 2007 VL 34 IS 6 AR L06202 DI 10.1029/2006GL028841 PG 5 WC Geosciences, Multidisciplinary SC Geology GA 155BI UT WOS:000245552300002 ER PT J AU Terenzi, F Hall, TM Khatiwala, S Rodehacke, CB Lebel, DA AF Terenzi, F. Hall, T. M. Khatiwala, S. Rodehacke, C. B. LeBel, D. A. TI Uptake of natural and anthropogenic carbon by the Labrador Sea SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID ATLANTIC-OCEAN; CO2; WATER; RATES AB We apply to Classical Labrador Sea Water (CLSW) the transit-time distribution (TTD) method to estimate the inventory and uptake of anthropogenic carbon dioxide (Cant). A model of TTDs representing bulk-advection and diffusive mixing is constrained with CFC11 data. The constrained TTDs are used to propagate Cant into CLSW, allowing the air-sea disequilibrium to evolve consistently. Cant in the Labrador Sea (LS) surface waters cannot keep pace with increasing atmospheric CO2 and is highly undersaturated. Our best estimate for 2001 is an anthropogenic inventory of 1.0 Gt C and an uptake of 0.02 Gt C/year. By additionally using the constraint of present-day CO2 measurements, we estimate that the preindustrial LS was neutral or a weak source of CO2 to the atmosphere. Our estimates are subject to possible error due to the assumption of steady-state transport and carbon biochemistry. C1 Columbia Univ, Dept Appl Phys & Appl Math, New York, NY 10027 USA. NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Columbia Univ, Lamont Doherty Earth Observ, New York, NY 10960 USA. RP Terenzi, F (reprint author), Columbia Univ, Dept Appl Phys & Appl Math, 200 SW Mudd Bldg,500 W 120th St, New York, NY 10027 USA. EM ft2104@columbia.edu NR 18 TC 9 Z9 9 U1 0 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD MAR 27 PY 2007 VL 34 IS 6 AR L06608 DI 10.1029/2006GL028543 PG 5 WC Geosciences, Multidisciplinary SC Geology GA 155BI UT WOS:000245552300001 ER PT J AU Rhee, YM Lee, TJ Gudipati, MS Allamandola, LJ Head-Gordon, M AF Rhee, Young Min Lee, Timothy J. Gudipati, Murthy S. Allamandola, Louis J. Head-Gordon, Martin TI Charged polycyclic aromatic hydrocarbon clusters and the galactic extended red emission SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article DE dimer; excited state; interstellar medium; nanoparticles ID DIFFUSE INTERSTELLAR-MEDIUM; DENSITY-FUNCTIONAL THEORY; AMORPHOUS-CARBON GRAINS; REFLECTION NEBULAE; BASIS-SETS; INFRARED-EMISSION; EXCITED-STATES; RECTANGLE; LUMINESCENCE; MOLECULES AB The species responsible for the broad extended red emission (ERE), discovered in 1975 and now known to be widespread throughout the Galaxy, still is unidentified. Spanning the range from approximate to 540 to 900 nm, the ERE is a photoluminescent process associated with a wide variety of different interstellar environments. Over the years, a number of plausible candidates have been suggested, but subsequent observations ruled them out. The objects that present the ERE also emit the infrared features attributed to free polycyclic aromatic hydrocarbon (PAH) molecules, suggesting that closely related materials are plausible ERE carriers. Here, we show that the peculiar spectra and unique properties of closed-shell cationic PAH dimers satisfy the existing observational constraints and suggest that emission from mixtures of charged PAH clusters accounts for much of the ERE. This work provides a view into the structures, stabilities, abundances, and ionization balance of PAH-related species in the emission zones, which, in turn, reflects physical conditions in the emission zones and sheds fundamental light on the nanoscale processes involved in carbon-particle nucleation and growth and carbonaceous dust evolution in the interstellar medium. C1 NASA, Ames Res Ctr, Astrochem Lab, Moffett Field, CA 94035 USA. Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. Lawrence Berkeley Natl Lab, Div Chem Sci, Berkeley, CA 94720 USA. Univ Maryland, Inst Phys Sci & Technol, College Pk, MD 20742 USA. RP Allamandola, LJ (reprint author), NASA, Ames Res Ctr, Astrochem Lab, MS 245-6, Moffett Field, CA 94035 USA. EM lallamandola@mail.arc.nasa.gov; mhg@cchem.berkeley.edu RI Gudipati, Murthy/F-7575-2011; Lee, Timothy/K-2838-2012; Rhee, Young/E-9940-2012 NR 56 TC 57 Z9 57 U1 1 U2 13 PU NATL ACAD SCIENCES PI WASHINGTON PA 2101 CONSTITUTION AVE NW, WASHINGTON, DC 20418 USA SN 0027-8424 J9 P NATL ACAD SCI USA JI Proc. Natl. Acad. Sci. U. S. A. PD MAR 27 PY 2007 VL 104 IS 13 BP 5274 EP 5278 DI 10.1073/pnas.0609396104 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 152AE UT WOS:000245331700006 PM 17372209 ER PT J AU Zhang, RY Li, GH Fan, JW Wu, DL Molina, MJ AF Zhang, Renyi Li, Guohui Fan, Jiwen Wu, Dong L. Molina, Mario J. TI Intensification of Pacific storm track linked to Asian pollution SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article DE aerosols; climate; clouds ID AIR-POLLUTION; CLIMATE; CLOUDS; VARIABILITY; EMISSIONS; SULFUR; ALBEDO; URBAN; ISCCP; SNOW AB Indirect radiative forcing of atmospheric aerosols by modification of cloud processes poses the largest uncertainty in climate prediction. We show here a trend of increasing deep convective clouds over the Pacific Ocean in winter from long-term satellite cloud measurements (1984-2005). Simulations with a cloud-resolving weather research and forecast model reveal that the increased deep convective clouds are reproduced when accounting for the aerosol effect from the Asian pollution outflow, which leads to large-scale enhanced convection and precipitation and hence an intensifed storm track over the Pacific. We suggest that the wintertime Pacific is highly vulnerable to the aerosol-cloud interaction because of favorable cloud dynamical and microphysical conditions from the coupling between the Pacific storm track and Asian pollution outflow. The intensified Pacific storm track is climatically significant and represents possibly the first detected climate signal of the aerosol-cloud interaction associated with anthropogenic pollution. In addition to radiative forcing on climate, intensification of the Pacific storm track likely impacts the global general circulation due to its fundamental role in meridional heat transport and forcing of stationary waves. C1 Texas A&M Univ, Dept Atmospher Sci, College Stn, TX 77843 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Calif San Diego, Dept Chem & Biochem, La Jolla, CA 92093 USA. RP Zhang, RY (reprint author), Texas A&M Univ, Dept Atmospher Sci, College Stn, TX 77843 USA. EM zhang@ariel.met.tamu.edu; mjmolina@ucsd.edu RI Fan, Jiwen/E-9138-2011; Zhang, Renyi/A-2942-2011; Wu, Dong/D-5375-2012 NR 33 TC 113 Z9 115 U1 6 U2 36 PU NATL ACAD SCIENCES PI WASHINGTON PA 2101 CONSTITUTION AVE NW, WASHINGTON, DC 20418 USA SN 0027-8424 J9 P NATL ACAD SCI USA JI Proc. Natl. Acad. Sci. U. S. A. PD MAR 27 PY 2007 VL 104 IS 13 BP 5295 EP 5299 DI 10.1073/pnas.0700618104 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 152AE UT WOS:000245331700010 PM 17374719 ER PT J AU Valentine, PC Collie, JS Reid, RN Asch, RG Guida, VG Blackwood, DS AF Valentine, Page C. Collie, Jeremy S. Reid, Robert N. Asch, Rebecca G. Guida, Vince G. Blackwood, Dann S. TI The occurrence of the colonial ascidian Didemnum sp on Georges Bank gravel habitat - Ecological observations and potential effects on groundfish and scallop fisheries SO JOURNAL OF EXPERIMENTAL MARINE BIOLOGY AND ECOLOGY LA English DT Article; Proceedings Paper CT 1st International Invasive Sea Squirt Conference CY APR 21-22, 2005 CL Woods Hole Oceanog Inst, Wood Hole, MA HO Woods Hole Oceanog Inst DE colonial ascidian; colonial tunicate; Didemnum; Georges Bank; gravel habitat C1 US Geol Survey, Woods Hole Sci Ctr, Woods Hole, MA 02543 USA. Univ Rhode Isl, Grad Sch Oceanog, Narragansett, RI 02882 USA. Natl Marine Fisheries Serv, Howard Lab, Highlands, NJ 07732 USA. RP Valentine, PC (reprint author), US Geol Survey, Woods Hole Sci Ctr, 384 Woods Hole Rd, Woods Hole, MA 02543 USA. EM pvalentine@usgs.gov NR 4 TC 46 Z9 51 U1 0 U2 7 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-0981 J9 J EXP MAR BIOL ECOL JI J. Exp. Mar. Biol. Ecol. PD MAR 26 PY 2007 VL 342 IS 1 SI SI BP 179 EP 181 DI 10.1016/j.jembe.2006.10.038 PG 3 WC Ecology; Marine & Freshwater Biology SC Environmental Sciences & Ecology; Marine & Freshwater Biology GA 142SE UT WOS:000244669400025 ER PT J AU Wojtecki, RJ Tyson, DS Ilhan, F Scheiman, DA Meador, MA AF Wojtecki, Rudy James Tyson, Daniel S. Ilhan, Faysal Scheiman, Daniel A. Meador, Michael A. TI Photocurable polymers through the Diels-Alder trapping of photochemically generated enols SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 [Wojtecki, Rudy James] Hiram Coll, Dept Chem, Hiram, OH 44135 USA. [Tyson, Daniel S.] Ohio Aerosp Inst, Mat & Struct Div, Cleveland, OH 44135 USA. [Meador, Michael A.] NASA, Glenn Res Ctr, Mat & Struct Div, Cleveland, OH 44135 USA. [Ilhan, Faysal] Abu Dhabi Univ, Dept Nat Sci & Chem, Abu Dhabi, U Arab Emirates. [Scheiman, Daniel A.] ASRC Aerosp, Mat & Struct Div, Cleveland, OH 44135 USA. EM wojteckirj@hiram.edu; daniel.s.tyson@nasa.gov; ulvi.ilhan@abu.ac.ae; daniel.a.scheiman@nasa.gov; Michael.A.Meador@nasa.gov NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 25 PY 2007 VL 233 MA 803-CHED BP 55 EP 55 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA V14GL UT WOS:000207722803048 ER PT J AU Perera, MI Hepp, AF Baird, MJ Brothers, SM Schierloh, EM Duffy, NV AF Perera, Melanie I. Hepp, Aloysius F. Baird, Michael J. Brothers, Scott M. Schierloh, Emilie M. Duffy, Norman V. TI Thermal decomposition of In(III) dithiocarbamates: A combined GC/MS and TGA study SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 [Perera, Melanie I.; Baird, Michael J.; Duffy, Norman V.] Wheeling Jesuit Univ, Dept Chem, Wheeling, WV 26003 USA. [Hepp, Aloysius F.] NASA, Glenn Res Ctr, Photovolta & Space Environm Effects Branch, Cleveland, OH 44135 USA. [Brothers, Scott M.] Texas A&M Univ, Dept Chem, College Stn, TX 77843 USA. [Schierloh, Emilie M.] Northwestern Univ, Dept Chem, Evanston, IL 60208 USA. EM Aloysius.F.Hepp@grc.nasa.gov; baird@wju.edu; sbrothers@mail.chem.tamu.edu; e-schierloh@northwestern.edu; nduffy@wju.edu NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 25 PY 2007 VL 233 MA 1284-CHED BP 318 EP 318 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA V14GL UT WOS:000207722803310 ER PT J AU Reynolds, JO Huff, J Holtorf, H Bradley, RK Jeevarajan, AS Moore, VC Conyers, JL AF Reynolds, Julia O'Bryan Huff, Janice Holtorf, Heidi Bradley, R. Kelley Jeevarajan, Antony S. Moore, Valerie C. Conyers, Jodie L. TI Utility of dendrofullerene DF-1 nanoparticles for radioprotection in cells SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 [Reynolds, Julia O'Bryan] Centenary Coll Louisiana, Dept Biophys, Shreveport, LA 71104 USA. [Huff, Janice; Holtorf, Heidi; Bradley, R. Kelley] Johnson Space Ctr, Human Adaptat & Countermeasures Off, Houston, TX 77096 USA. [Jeevarajan, Antony S.] Wyle Life Sci, Biotechnol Program, Houston, TX 77058 USA. [Moore, Valerie C.] Univ Texas Hlth Sci Ctr Houston, Dept Internal Med, Houston, TX 77030 USA. EM jreynold@centenary.edu; Valerie.Moore@uth.tmc.edu; Jodie.L.Conyers@uth.tmc.edu NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 25 PY 2007 VL 233 MA 497-CHED BP 365 EP 365 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA V14GL UT WOS:000207722804364 ER PT J AU Sun, XH Yu, B AF Sun, Xuhui Yu, Bin TI Phase-change nanowire: Synthesis and nanoscale thermal encoding SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 [Sun, Xuhui; Yu, Bin] NASA, Ames Res Ctr, Ames Ctr Adv Aerosp Mat & Devices, Moffett Field, CA 94035 USA. EM xsun@arc.nasa.gov RI Sun, Xuhui /K-5689-2012 NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 25 PY 2007 VL 233 MA 674-INOR BP 450 EP 450 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA V14GL UT WOS:000207722805439 ER PT J AU Jose, MJ Baird, MJ Hepp, AF Duffy, NV AF Jose, Melanie J. Baird, Michael J. Hepp, Aloysius F. Duffy, Norman V. TI Thermogravimetric analysis studies of iron(III) dithiocarbamates SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 [Jose, Melanie J.; Baird, Michael J.; Duffy, Norman V.] Wheeling Jesuit Univ, Dept Chem, Wheeling, WV 26003 USA. [Hepp, Aloysius F.] NASA Glenn Res Ctr, Photovolta & Space Environm Effects Branch, Cleveland, OH 44135 USA. EM baird@wju.edu; Aloysius.F.Hepp@grc.nasa.gov; nduffy@wju.edu NR 0 TC 0 Z9 0 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 25 PY 2007 VL 233 MA 1285-CHED BP 466 EP 466 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA V14GL UT WOS:000207722803458 ER PT J AU Allamandola, LJ AF Allamandola, Louis J. TI Chemical evolution in the interstellar medium SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 [Allamandola, Louis J.] NASA, Ames Res Ctr, Astrochem Lab, Moffett Field, CA 94035 USA. EM lallamandola@mail.arc.nasa.gov NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 25 PY 2007 VL 233 MA 1626-CHED BP 585 EP 585 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA V14GL UT WOS:000207722804583 ER PT J AU Waterhouse, KA Hammond, D Jeevarajan, A Huff, J Bradley, K Conyers, JL Moore, V AF Waterhouse, Kelly A. Hammond, Dianne Jeevarajan, Antony Huff, Janice Bradley, Kelley Conyers, Jodie L. Moore, Valerie TI Proteomic analysis of cultured cells in the presence of carbon nanomaterials SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 [Waterhouse, Kelly A.] Centenary Coll Louisiana, Dept Chem, Shreveport, LA 71134 USA. [Hammond, Dianne; Jeevarajan, Antony; Huff, Janice; Bradley, Kelley] Johnson Space Ctr, Human Adaptat & Countermeasures Off, Houston, TX USA. [Conyers, Jodie L.; Moore, Valerie] Univ Texas Hlth Sci Ctr Houston, Houston, TX USA. EM kwaterho@centenary.edu NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 25 PY 2007 VL 233 MA 480-CHED BP 728 EP 728 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA V14GL UT WOS:000207722804725 ER PT J AU Geiger, CL Clausen, CA Quinn, J O'Hara, S Krug, TA Wolters, J Corbin, M AF Geiger, Cherie L. Clausen, Christian A. Quinn, Jacqueline O'Hara, Suzanne Krug, Tom A. Wolters, Jeanna Corbin, Michael TI I&EC 21-Novel physical and chemical properties of zeolitic nanomaterials SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 [Geiger, Cherie L.; Clausen, Christian A.] Univ Cent Florida, Dept Chem, Orlando, FL 32816 USA. [O'Hara, Suzanne; Krug, Tom A.] Geosyntec Consultants, Guelph, ON N1G 5G3, Canada. [Wolters, Jeanna; Corbin, Michael] Weston Solut, W Chester, PA 19380 USA. [Quinn, Jacqueline] NASA, Kennedy Space Ctr, Washington, DC 20546 USA. EM cgeiger@mail.ucf.edu; clausen@mail.ucf.edu; jacqueline.quinn@nasa.gov; SO'Hara@GeoSyntec.com; tkrug@geosyntec.com; j.wolters@westonsolutions.com; M.Corbin@westonsolutions.com NR 0 TC 0 Z9 0 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 25 PY 2007 VL 233 MA 178-IEC BP 834 EP 834 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA V14GL UT WOS:000207722802736 ER PT J AU Whitacre, JF Smart, MC West, WC Bugga, RV Yazami, R Hamwi, A Prakash, GKS AF Whitacre, Jay F. Smart, Marshall C. West, William C. Bugga, Ratnakumar V. Yazami, Rachid Hamwi, A. Prakash, G. K. Surya TI FLUO 26-The use of nanocomposite CFx cathode materials in Li-CFx batteries for low temperature application SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 [Whitacre, Jay F.; Smart, Marshall C.; West, William C.; Bugga, Ratnakumar V.] CALTECH, Jet Prop Lab, Electrochem Technol Grp, Pasadena, CA 91109 USA. [Yazami, Rachid] CALTECH, CNRS Lab, Pasadena, CA 91106 USA. [Hamwi, A.] Univ Clermont Ferrand, F-63177 Clermont Ferrand, France. [Prakash, G. K. Surya] Univ So Calif, Loker Hydrocarbon Res Inst, Los Angeles, CA 90089 USA. [Prakash, G. K. Surya] Univ So Calif, Dept Chem, Los Angeles, CA 90089 USA. EM Whitacre@jpl.nasa.gov; Marshall.C.Smart@jpl.nasa.gov; gprakash@usc.edu NR 0 TC 0 Z9 0 U1 0 U2 5 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 25 PY 2007 VL 233 MA 26-FLUO BP 971 EP 971 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA V14GL UT WOS:000207722800810 ER PT J AU Smart, MC Smith, K Bhalla, P Hu, JB Prakash, GKS Whitacre, JF Bugga, RV AF Smart, Marshall C. Smith, Kiah Bhalla, Pooja Hu, Jinbo Prakash, G. K. Surya Whitacre, Jay F. Bugga, Ratnakumar V. TI FLUO 25-The development of improved lithium-ion battery electrolytes containing fluorinated cosolvents SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 [Smart, Marshall C.; Whitacre, Jay F.; Bugga, Ratnakumar V.] CALTECH, Jet Prop Lab, Electrochem Technol Grp, Pasadena, CA 91109 USA. [Smith, Kiah; Bhalla, Pooja; Hu, Jinbo; Prakash, G. K. Surya] Univ So Calif, Loker Hydrocarbon Res Inst, Los Angeles, CA 90089 USA. [Smith, Kiah; Bhalla, Pooja; Hu, Jinbo; Prakash, G. K. Surya] Univ So Calif, Dept Chem, Los Angeles, CA 90089 USA. EM Marshall.C.Smart@jpl.nasa.gov; jinbohu@usc.edu; gprakash@usc.edu; Whitacre@jpl.nasa.gov NR 0 TC 0 Z9 0 U1 0 U2 4 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 25 PY 2007 VL 233 MA 25-FLUO BP 974 EP 974 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA V14GL UT WOS:000207722800813 ER PT J AU DeCola, PL Miller, CE Crisp, D AF DeCola, Philip L. Miller, Charles E. Crisp, David TI Vibrational spectroscopic probe of a global-scale biological system: NASA's Orbiting Carbon Observatory SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 [DeCola, Philip L.] NASA Headquarters, Sci Mission Directorate, Div Earth Sci, Washington, DC 20546 USA. [Miller, Charles E.; Crisp, David] CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. EM pdecola@nasa.gov; charles.e.miller@jpl.nasa.gov; David.Crisp@jpl.nasa.gov NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 25 PY 2007 VL 233 MA 37-PHYS PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA V14GL UT WOS:000207722807326 ER PT J AU Meador, MAB Tigelaar, DM Chapin, K Bennett, WR AF Meador, Mary Ann B. Tigelaar, Dean M. Chapin, Kara Bennett, William R. TI Use of ionic liquids in rod-coil block copolyimides for improved lithium ion conduction SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract CT 233rd National Meeting of the Cellulose-and-Renewable-Materials-Division of the American-Chemical-Society (ACS) CY MAR 25-29, 2007 CL Chicago, IL SP Amer Chem Soc (ACS), Cellulose & Renewable Mat Div C1 [Meador, Mary Ann B.; Chapin, Kara] NASA, Mat & Struct Div, Glenn Res Ctr, Cleveland, OH 44135 USA. [Tigelaar, Dean M.] NASA, Ohio Aerosp Inst, Glenn Res Ctr, Cleveland, OH 44135 USA. [Bennett, William R.] NASA, QSS Grp, Glenn Res Ctr, Cleveland, OH 44135 USA. EM maryann.meador@nasa.gov; dean.m.tigelaar@grc.nasa.gov; william.r.bennett@grc.nasa.gov NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 25 PY 2007 VL 233 MA 164-POLY PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA V14GO UT WOS:000207723100166 ER PT J AU Meador, MA Tyson, DS Ilhan, F AF Meador, Michael A. Tyson, Daniel S. Ilhan, Faysal TI Aromatic diimides from the Diels-Alder trapping of o-methylphenyl ketone derived photoenols: Synthesis and photophysics SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 [Meador, Michael A.] NASA Glenn Res Ctr, Mat & Struct Div, Cleveland, OH 44135 USA. [Tyson, Daniel S.] Ohio Aerosp Inst, Mat & Struct Div, Cleveland, OH 44135 USA. [Ilhan, Faysal] Abu Dhabi Univ, Dept Nat Sci & Chem, Abu Dhabi, U Arab Emirates. EM Michael.A.Meador@nasa.gov; daniel.s.tyson@nasa.gov; ulvi.ilhan@abu.ac.ae NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 25 PY 2007 VL 233 MA 801-ORGN PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA V14GL UT WOS:000207722808429 ER PT J AU Tyson, DS Minton, W Accurso, AA Desupda, P Figueroa, AA Scheiman, DA Meador, MA AF Tyson, Daniel S. Minton, William Accurso, Adrian A. Desupda, Pushan Figueroa, Amalia A. Scheiman, Daniel A. Meador, Michael A. TI Synthesis and characterization of azobenzene containing photoresponsive rod-coil polymers SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract CT 233rd National Meeting of the Cellulose-and-Renewable-Materials-Division of the American-Chemical-Society (ACS) CY MAR 25-29, 2007 CL Chicago, IL SP Amer Chem Soc (ACS), Cellulose & Renewable Mat Div C1 [Tyson, Daniel S.] Ohio Aerosp Inst, Mat & Struct Div, Cleveland, OH 44135 USA. [Meador, Michael A.] NASA, Mat & Struct Div, Glenn Res Ctr, Cleveland, OH 44135 USA. [Minton, William] Carnegie Mellon Univ, Dept Chem, Pittsburgh, PA 15213 USA. [Accurso, Adrian A.] Scripps Res Inst, Dept Chem, La Jolla, CA 92037 USA. [Desupda, Pushan] Harvard Univ, Dept Chem, Cambridge, MA 02138 USA. [Figueroa, Amalia A.] Univ Puerto Rico, Dept Chem, Rio Piedras, PR 00931 USA. [Scheiman, Daniel A.] ASRC Aerosp, Mat & Struct Div, Cleveland, OH 44135 USA. EM daniel.s.tyson@nasa.gov; daniel.a.scheiman@nasa.gov; Michael.A.Meador@nasa.gov NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 25 PY 2007 VL 233 MA 238-POLY PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA V14GO UT WOS:000207723100282 ER PT J AU Vander Wal, RL Berger, GM AF Vander Wal, Randy L. Berger, Gordon M. TI Review of flame (combustion) synthesis of carbon nanotubes and nanofibers SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 [Vander Wal, Randy L.; Berger, Gordon M.] NASA Glenn, Nanotechnol Lab, USRA, Cleveland, OH 44135 USA. EM randy@rvander.grc.nasa.gov NR 0 TC 0 Z9 0 U1 1 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 25 PY 2007 VL 233 MA 17-FUEL PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA V14GL UT WOS:000207722801710 ER PT J AU Xie, HZ Li, YF Trent, JD Swanson, BI AF Xie, Hongzhi Li, Yi-Fen Trent, Jonathan D. Swanson, Basil I. TI Interaction of the engineered chaperonin proteins with water-soluble quantum dots SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 [Xie, Hongzhi; Swanson, Basil I.] Los Alamos Natl Lab, Div Chem, Los Alamos, NM 87545 USA. [Li, Yi-Fen; Trent, Jonathan D.] NASA, Ames Res Ctr, Bioengn Branch, Prot Nanotechnol Grp, Moffett Field, CA 94035 USA. EM hongzhi@lanl.gov; yli2@mail.arc.nasa.gov; basil@lanl.gov NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD MAR 25 PY 2007 VL 233 MA 564-COLL PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA V14GL UT WOS:000207722801595 ER PT J AU Kishi, MJ Megrey, BA Ito, SI Werner, FE AF Kishi, Michio J. Megrey, Bernard A. Ito, Shin-Ichi Werner, Francisco E. TI Special issue on NEMURO and NEMURO.FISH - Preface SO ECOLOGICAL MODELLING LA English DT Editorial Material C1 Hokkaido Univ, Fac Fisheries Sci N13, Sapporo, Hokkaido 0600813, Japan. Alaska Fisheries Sci Ctr, Natl Marine Fisheries Serv, Juneau, AK 99802 USA. Univ N Carolina, Chapel Hill, NC USA. RP Kishi, MJ (reprint author), Hokkaido Univ, Fac Fisheries Sci N13, W8, Sapporo, Hokkaido 0600813, Japan. EM mjkishi@nifty.com RI Ito, Shin-ichi/E-2981-2012 OI Ito, Shin-ichi/0000-0002-3635-2580 NR 0 TC 4 Z9 4 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0304-3800 EI 1872-7026 J9 ECOL MODEL JI Ecol. Model. PD MAR 24 PY 2007 VL 202 IS 1-2 SI SI BP 3 EP 6 DI 10.1016/j.ecolmodel.2006.10.008 PG 4 WC Ecology SC Environmental Sciences & Ecology GA 151SL UT WOS:000245311000002 ER PT J AU Kletetschka, G Pruner, P Venhodova, D Kadlec, J AF Kletetschka, Gunther Pruner, Petr Venhodova, Daniela Kadlec, Jaroslav TI Magnetic record associated with tree ring density: Possible climate proxy SO GEOCHEMICAL TRANSACTIONS LA English DT Article ID PINE PINUS-LONGAEVA; TELOMERASE ACTIVITY; LIFE-SPANS; LENGTH; FIRE; AGE AB A magnetic signature of tree rings was tested as a potential paleo-climatic indicator. We examined wood from sequoia tree, located in Mountain Home State Forest, California, whose tree ring record spans over the period 600 - 1700 A. D. We measured low and high-field magnetic susceptibility, the natural remanent magnetization ( NRM), saturation isothermal remanent magnetization ( SIRM), and stability against thermal and alternating field ( AF) demagnetization. Magnetic investigation of the 200 mm long sequoia material suggests that magnetic efficiency of natural remanence may be a sensitive paleoclimate indicator because it is substantially higher ( in average > 1%) during the Medieval Warm Epoch ( 700 - 1300 A. D.) than during the Little Ice Age ( 1300 - 1850 A. D.) where it is < 1%. Diamagnetic behavior has been noted to be prevalent in regions with higher tree ring density. The mineralogical nature of the remanence carrier was not directly detected but maghemite is suggested due to low coercivity and absence of Verwey transition. Tree ring density, along with the wood's magnetic remanence efficiency, records the Little Ice Age ( LIA) well documented in Europe. Such a record suggests that the European LIA was a global phenomenon. Magnetic analysis of the thermal stability reveals the blocking temperatures near 200 degree C. This phenomenon suggests that the remanent component in this tree may be thermal in origin and was controlled by local thermal condition. C1 Acad Sci Czech Republ, Inst Geol, CR-16502 Prague, Czech Republic. Catholic Univ Amer, Dept Phys, Washington, DC 20064 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Kletetschka, G (reprint author), Acad Sci Czech Republ, Inst Geol, CR-16502 Prague, Czech Republic. EM kletetschka@nasa.gov; Pruner@gli.cas.cz; venhodova@gli.cas.cz; Kadlec@gli.cas.cz RI Kletetschka, Gunther/C-9996-2011; Pruner, Petr/I-8786-2014; Kadlec, Jaroslav/H-6391-2014 OI Kletetschka, Gunther/0000-0002-0645-9037; NR 17 TC 0 Z9 0 U1 0 U2 9 PU BIOMED CENTRAL LTD PI LONDON PA MIDDLESEX HOUSE, 34-42 CLEVELAND ST, LONDON W1T 4LB, ENGLAND SN 1467-4866 J9 GEOCHEM T JI Geochem. Trans. PD MAR 24 PY 2007 VL 8 AR 2 DI 10.1186/1467-4866-8-2 PG 11 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 157LW UT WOS:000245722200001 PM 17381844 ER PT J AU Bauer, SE Mishchenko, MI Lacis, AA Zhang, S Perlwitz, J Metzger, SM AF Bauer, S. E. Mishchenko, M. I. Lacis, A. A. Zhang, S. Perlwitz, J. Metzger, S. M. TI Do sulfate and nitrate coatings on mineral dust have important effects on radiative properties and climate modeling? SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID GENERAL-CIRCULATION MODEL; AEROSOL-PARTICLES; OPTICAL-PROPERTIES; CARBON; SIMULATION; EMISSION; SINGLE; SPACE; BLACK; AIR AB Coating of mineral dust particles by air pollutants leads to core-mantle particles. These composite aerosols could interact differently with atmospheric radiation than the uncoated dust. In our simplified radiative calculations we assumed that a spherical dust core is covered uniformly by a liquid refractive material, such as sulfate or nitrate. Theoretical calculations of optical properties of such particles show that the single-scattering albedo and the asymmetry parameter of core-mantle aerosols only differ significantly from uncoated dust if coating layers exceed 20% of the radius of the dust core. Global simulations of sulfate/nitrate-coated dust particles show that the thickness of the shell can be expected to range from 0 to 20% of the radius of the dust core. The result of this work is that mineral dust particles can be treated as external mixture within radiative calculations but the coating processes lead to changed loads in sulfate, nitrate, and mineral dust aerosol loads and therefore change their impact on Earth radiation. The combined anthropogenic forcing of dust, nitrate, and sulfate aerosols is -0.1 W/m(2); however, excluding heterogeneous interactions leads to a 3 times larger negative forcing. C1 NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Columbia Univ, Earth Inst, New York, NY USA. MIT, Dept Earth Atmosphere & Planetary Sci, Cambridge, MA USA. Columbia Univ, Dept Appl Phys & Appl Math, New York, NY USA. Max Planck Inst Chem, Mainz, Germany. RP Bauer, SE (reprint author), NASA, Goddard Inst Space Studies, 2880 Broadway, New York, NY 10025 USA. EM sbauer@giss.nasa.gov RI Lacis, Andrew/D-4658-2012; Bauer, Susanne/P-3082-2014; Mishchenko, Michael/D-4426-2012 NR 35 TC 45 Z9 46 U1 1 U2 17 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAR 24 PY 2007 VL 112 IS D6 AR D06307 DI 10.1029/2005JD006977 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 150AK UT WOS:000245187800002 ER PT J AU King, NE Argus, D Langbein, J Agnew, DC Bawden, G Dollar, RS Liu, Z Galloway, D Reichard, E Yong, A Webb, FH Bock, Y Stark, K Barseghian, D AF King, N. E. Argus, D. Langbein, J. Agnew, D. C. Bawden, G. Dollar, R. S. Liu, Z. Galloway, D. Reichard, E. Yong, A. Webb, F. H. Bock, Y. Stark, K. Barseghian, D. TI Space geodetic observation of expansion of the San Gabriel Valley, California, aquifer system, during heavy rainfall in winter 2004-2005 SO JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH LA English DT Article ID METROPOLITAN LOS-ANGELES; BLIND-THRUST-FAULT; SOUTHERN-CALIFORNIA; TIME-SERIES; RADAR INTERFEROMETRY; EARTHQUAKE SEQUENCE; TECTONIC ANALYSIS; SLIP; GPS; DEFORMATION AB [1] Starting early in 2005, the positions of GPS stations in the San Gabriel valley region of southern California showed statistically significant departures from their previous behavior. Station LONG moved up by about 47 mm, and nearby stations moved away from LONG by about 10 mm. These changes began during an extremely rainy season in southern California and coincided with a 16-m increase in water level at a nearby well in Baldwin Park and a regional uplift detected by interferometric synthetic aperture radar. No equivalent signals were seen in GPS station position time series elsewhere in southern California. Our preferred explanation, supported by the timing and by a hydrologic simulation, is deformation due to recharging of aquifers after near-record rainfall in 2004 - 2005. We cannot rule out an aseismic slip event, but we consider such an event unlikely because it requires slip on multiple faults and predicts other signals that are not observed. C1 US Geol Survey, Pasadena, CA 91106 USA. US Geol Survey, Menlo Pk, CA 94025 USA. Calif Water Sci Ctr, US Geol Survey, San Diego, CA 92101 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Stark Stark Consulting LLC, Pasadena, CA 91106 USA. US Geol Survey, Sacramento, CA 95819 USA. Univ Calif San Diego, Inst Geophys & Planetary Phys, La Jolla, CA 92093 USA. RP King, NE (reprint author), US Geol Survey, 525 S Wilson Ave, Pasadena, CA 91106 USA. EM nking@usgs.gov RI Argus, Donald/F-7704-2011; Liu, Zhen/D-8334-2017; OI Galloway, Devin/0000-0003-0904-5355 NR 56 TC 32 Z9 34 U1 1 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9313 EI 2169-9356 J9 J GEOPHYS RES-SOL EA JI J. Geophys. Res.-Solid Earth PD MAR 24 PY 2007 VL 112 IS B3 AR B03409 DI 10.1029/2006JB004448 PG 11 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 150FE UT WOS:000245200200003 ER PT J AU Rosi, M Bauschlicher, CW AF Rosi, Marzio Bauschlicher, Charles W., Jr. TI The functionalization of (5,5), (9,0), and (10,0) single wall carbon nanotubes by CHn fragments SO CHEMICAL PHYSICS LETTERS LA English DT Article ID GEOMETRY OPTIMIZATION; MOLECULAR-MECHANICS; GLOW-DISCHARGE; SPECTROSCOPY AB The binding energies of CH3, CH3 + H, CH2, and CH to (5, 5), (9, 0), and (10, 0) carbon nanotubes are determined computationally. The binding energy of a single CH3 is very small because only one adsorbate-tube bond is formed for the loss of one tube pi bond. For CH3 + H, CH2 and CH the binding energies are much larger since two adsorbate-tube bonds form for the loss of one tube pi bond. For CH2 and CH, which bond with two different tube atoms, for some orientations a strong bonding with the tube occurs that results in the breaking of a tube C-C bond. The calculated IR spectra show that the C-H stretching and H-C-H bending regions offer the possibility of observing these species. (c) 2007 Elsevier B.V. All rights reserved. C1 Univ Perugia, Dept Chem, CNR, ISTM, I-06100 Perugia, Italy. NASA, Ames Res Ctr, Ctr Adv Mat & Devices, Moffett Field, CA 94035 USA. RP Rosi, M (reprint author), Univ Perugia, Dept Chem, CNR, ISTM, I-06100 Perugia, Italy. EM marzio@thch.unipg.it; chlicher@nasa.gov RI Rosi, Marzio/L-5748-2015 OI Rosi, Marzio/0000-0002-1264-3877 NR 20 TC 12 Z9 12 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2614 J9 CHEM PHYS LETT JI Chem. Phys. Lett. PD MAR 22 PY 2007 VL 437 IS 1-3 BP 99 EP 103 DI 10.1016/j.cplett.2007.02.002 PG 5 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 152ZN UT WOS:000245401200019 ER PT J AU Emmons, LK Pfister, GG Edwards, DP Gille, JC Sachse, G Blake, D Wofsy, S Gerbig, C Matross, D Nedelec, P AF Emmons, L. K. Pfister, G. G. Edwards, D. P. Gille, J. C. Sachse, G. Blake, D. Wofsy, S. Gerbig, C. Matross, D. Nedelec, P. TI Measurements of Pollution in the Troposphere (MOPITT) validation exercises during summer 2004 field campaigns over North America SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID FAST-RESPONSE; MEASUREMENTS ABOARD; INSTRUMENT; AIRCRAFT C1 Univ Calif Irvine, Dept Chem, Irvine, CA 92697 USA. Natl Ctr Atmospher Res, Div Atmospher Chem, Boulder, CO 80307 USA. Max Planck Inst Biogeochem, D-07745 Jena, Germany. Harvard Univ, Dept Earth & Planetary Sci, Cambridge, MA 02138 USA. CNRS, Lab Aerol, F-31400 Toulouse, France. NASA, Langley Res Ctr, Chem & Dynam Branch, Hampton, VA 23681 USA. RP Emmons, LK (reprint author), Univ Calif Irvine, Dept Chem, Irvine, CA 92697 USA. EM emmons@ucar.edu; drblake@uci.edu; wofsy@fas.harvard.edu; cgerbig@bgc-jena.mpg.de; nedp@aero.obs-mip.fr RI Pfister, Gabriele/A-9349-2008; Gerbig, Christoph/L-3532-2013; Emmons, Louisa/R-8922-2016 OI Gerbig, Christoph/0000-0002-1112-8603; Emmons, Louisa/0000-0003-2325-6212 NR 11 TC 64 Z9 64 U1 1 U2 7 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAR 22 PY 2007 VL 112 IS D12 AR D12S02 DI 10.1029/2006JD007833 PG 7 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 150BD UT WOS:000245189700001 ER PT J AU Todd, MC Washington, R Martins, JV Dubovik, O Lizcano, G M'Bainayel, S Engelstaedter, S AF Todd, Martin C. Washington, Richard Martins, Jose Vanderlei Dubovik, Oleg Lizcano, Gil M'Bainayel, Samuel Engelstaedter, Sebastian TI Mineral dust emission from the Bodele Depression, northern Chad, during BoDEx 2005 SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID SAHARAN DUST; RADIATIVE PROPERTIES; OPTICAL-PROPERTIES; EXPERIMENT SHADE; C-130 AIRCRAFT; GOCART MODEL; SOURCE AREAS; ERBE DATA; AEROSOL; AERONET AB Mineral dust in the atmosphere is an important component of the climate system but is poorly quantified. The Bodele Depression of northern Chad stands out as the world's greatest source region of mineral dust into the atmosphere. Frequent dust plumes are a distinguishing feature of the region's climate. There is a need for more detailed information on processes of dust emission/transport and dust optical properties to inform model simulations of this source. During the Bodele Dust Experiment (BoDEx) in 2005, instrumentation was deployed to measure dust properties and boundary layer meteorology. Observations indicate that dust emission events are triggered when near-surface wind speeds exceed 10 ms(-1), associated with synoptic-scale variability in the large-scale atmospheric circulation. Dust emission pulses in phase with the diurnal cycle of near-surface winds. Analysis of dust samples shows that the dust consists predominantly of fragments of diatomite sediment. The particle size distribution of this diatomite dust estimated from sun photometer data, using a modified Aeronet retrieval algorithm, indicates a dominant coarse mode (radius centered on 1-2 mu m) similar to other Saharan dust observations. Single-scattering albedo values are high, broadly in line with other Saharan dust even though the diatomite composition of dust from the Bodele is likely to be unusual. The radiative impact of high dust loadings results in a reduction in surface daytime maximum temperature of around 7 degrees C in the Bodele region. Using optical and physical properties of dust obtained in the field, we estimate the total dust flux emitted from the Bodele to be 1.18 +/- 0.45 Tg per day during a substantial dust event. We speculate that the Bodele Depression (similar to 10,800 km(2)) may be responsible for between 6-18% of global dust emissions, although the uncertainty in both the Bodele and global estimates remains high. C1 UCL, Dept Geog, London WC1E 6BT, England. Univ Oxford, Ctr Environm, Climat Res Lab, Oxford OX1 3QY, England. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Maryland Baltimore Cty, Baltimore, MD 21250 USA. Direct Ressources Eau & Meteorol, Ndjamena, Chad. RP Todd, MC (reprint author), UCL, Dept Geog, Pearson Bldg,Gower St, London WC1E 6BT, England. EM mtodd@geog.ucl.ac.uk RI Dubovik, Oleg/A-8235-2009; Engelstaedter, Sebastian/A-9599-2009; todd, martin/I-4143-2015; OI Dubovik, Oleg/0000-0003-3482-6460; Engelstaedter, Sebastian/0000-0001-9315-580X NR 47 TC 73 Z9 73 U1 0 U2 8 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAR 22 PY 2007 VL 112 IS D6 AR D06207 DI 10.1029/2006JD007170 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 150AH UT WOS:000245187500002 ER PT J AU Chandra, S Ziemke, JR Schoeberl, MR Froidevaux, L Read, WG Levelt, PF Bhartia, PK AF Chandra, S. Ziemke, J. R. Schoeberl, M. R. Froidevaux, L. Read, W. G. Levelt, P. F. Bhartia, P. K. TI Effects of the 2004 El Nino on tropospheric ozone and water vapor SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID SOUTHERN-OSCILLATION; AURA SATELLITE; EOS MLS; SIMULATION; EXCHANGE AB The global effects of the 2004 El Nino on tropospheric ozone and H(2)O based on Aura OMI and MLS measurements are analyzed. Although it was a weak El Nino from a historical perspective, it produced significant changes in these parameters in tropical latitudes. Tropospheric ozone increased by 10 - 20% over most of the western Pacific region and decreased by about the same amount over the eastern Pacific region. H(2)O in the upper troposphere showed similar changes but with opposite sign. These zonal changes in tropospheric ozone and H(2)O are caused by the eastward shift in the Walker circulation in the tropical pacific region during El Nino. During the 2004 El Nino, biomass burning did not have a significant effect on the ozone budget in the troposphere, unlike the 1997 El Nino. Zonally averaged tropospheric column ozone did not change significantly either globally or over tropical latitudes. C1 Univ Maryland Baltimore Cty, Catonsville, MD 21228 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. KNMI, NL-3730 AE De Bilt, Netherlands. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Chandra, S (reprint author), Univ Maryland Baltimore Cty, 5523 Res Pk Dr,Suite 320, Catonsville, MD 21228 USA. EM ziemke@jwocky.gsfc.nasa.gov RI Bhartia, Pawan/A-4209-2016 OI Bhartia, Pawan/0000-0001-8307-9137 NR 20 TC 19 Z9 19 U1 1 U2 5 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD MAR 21 PY 2007 VL 34 IS 6 AR L06802 DI 10.1029/2006GL028779 PG 5 WC Geosciences, Multidisciplinary SC Geology GA 149ZM UT WOS:000245185400002 ER PT J AU Massey, R Heymans, C Berge, J Bernstein, G Bridle, S Clowe, D Dahle, H Ellis, R Erben, T Hetterscheidt, M High, FW Hirata, C Hoekstra, H Hudelot, P Jarvis, M Johnston, D Kuijken, K Margoniner, V Mandelbaum, R Mellier, Y Nakajima, R Paulin-Henriksson, S Peeples, M Roat, C Refregier, A Rhodes, J Schrabback, T Schirmer, M Seljak, U Semboloni, E Van Waerbeke, L AF Massey, Richard Heymans, Catherine Berge, Joel Bernstein, Gary Bridle, Sarah Clowe, Douglas Dahle, Hakon Ellis, Richard Erben, Thomas Hetterscheidt, Marco High, F. William Hirata, Christopher Hoekstra, Henk Hudelot, Patrick Jarvis, Mike Johnston, David Kuijken, Konrad Margoniner, Vera Mandelbaum, Rachel Mellier, Yannick Nakajima, Reiko Paulin-Henriksson, Stephane Peeples, Molly Roat, Chris Refregier, Alexandre Rhodes, Jason Schrabback, Tim Schirmer, Mischa Seljak, Uros Semboloni, Elisabetta Van Waerbeke, Ludovic TI The shear testing programme 2: Factors affecting high-precision weak-lensing analyses SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE gravitational lensing; methods : data analysis; cosmology : observations ID LARGE-SCALE STRUCTURE; CLUSTER SURVEY FIELDS; COSMIC SHEAR; POWER-SPECTRUM; DARK-MATTER; SUPRIME-CAM; TELESCOPE; SHAPELETS; MASS; CONSTRAINTS AB The Shear Testing Programme (STEP) is a collaborative project to improve the accuracy and reliability of weak-lensing measurement, in preparation for the next generation of wide-field surveys. We review 16 current and emerging shear-measurement methods in a common language, and assess their performance by running them (blindly) on simulated images that contain a known shear signal. We determine the common features of algorithms that most successfully recover the input parameters. A desirable goal would be the combination of their best elements into one ultimate shear-measurement method. In this analysis, we achieve previously unattained discriminatory precision via a combination of more extensive simulations and pairs of galaxy images that have been rotated with respect to each other. That removes the otherwise overwhelming noise from their intrinsic ellipticities. Finally, the robustness of our simulation approach is confirmed by testing the relative calibration of methods on real data. Weak-lensing measurements have improved since the first STEP paper. Several methods now consistently achieve better than 2 per cent precision, and are still being developed. However, we can now distinguish all methods from perfect performance. Our main concern continues to be the potential for a multiplicative shear calibration bias: not least because this cannot be internally calibrated with real data. We determine which galaxy populations are responsible for bias and, by adjusting the simulated observing conditions, we also investigate the effects of instrumental and atmospheric parameters. The simulated point spread functions are not allowed to vary spatially, to avoid additional confusion from interpolation errors. We have isolated several previously unrecognized aspects of galaxy shape measurement, in which focused development could provide further progress towards the sub-per cent level of precision desired for future surveys. These areas include the suitable treatment of image pixellization and galaxy morphology evolution. Ignoring the former effect affects the measurement of shear in different directions, leading to an overall underestimation of shear and hence the amplitude of the matter power spectrum. Ignoring the second effect could affect the calibration of shear estimators as a function of galaxy redshift, and the evolution of the lensing signal, which will be vital to measure parameters including the dark energy equation of state. C1 CALTECH, Pasadena, CA 91125 USA. Univ British Columbia, Vancouver, BC V6T 1Z1, Canada. CEA Saclay, Serv Astrophys, F-91191 Gif Sur Yvette, France. Univ Penn, Dept Phys & Astron, Philadelphia, PA 19104 USA. UCL, Dept Phys & Astron, London WC1E 6BT, England. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. Univ Oslo, Inst Theoret Astrophys, N-0315 Oslo, Norway. Univ Bonn, Argelander Inst Astron, D-53121 Bonn, Germany. Harvard Univ, Dept Phys, Cambridge, MA 01238 USA. Inst Adv Study, Princeton, NJ 08540 USA. Univ Victoria, Victoria, BC V8P 5C2, Canada. Observ Midi Pyrenees, UMR 5572, F-31000 Toulouse, France. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Leiden Observ, NL-2300 RA Leiden, Netherlands. Univ Calif Davis, Dept Phys, Davis, CA 95616 USA. Princeton Univ, Dept Phys, Princeton, NJ 08544 USA. Univ Paris 06, CNRS, UMR 7095, Inst Astrophys Paris, F-75014 Paris, France. Observ Paris, LERMA, F-75014 Paris, France. INAF, Catania Astrophys Observ, I-95123 Catania, Italy. Ohio State Univ, Dept Astron, Columbus, OH 43210 USA. Isaac Newton Grp Telescopes, Santa Cruz De La Palma 38700, Spain. RP Massey, R (reprint author), CALTECH, 1200 E Calif Blvd, Pasadena, CA 91125 USA. EM rjm@astro.caltech.edu RI Mandelbaum, Rachel/N-8955-2014; OI Mandelbaum, Rachel/0000-0003-2271-1527; Hoekstra, Henk/0000-0002-0641-3231 NR 81 TC 247 Z9 249 U1 1 U2 5 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD MAR 21 PY 2007 VL 376 IS 1 BP 13 EP 38 DI 10.1111/j.1365-2966.2006.11315.x PG 26 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 145TC UT WOS:000244886400019 ER PT J AU Keenan, FP Jess, DB Aggarwal, KM Thomas, RJ Brosius, JW Davila, JM AF Keenan, F. P. Jess, D. B. Aggarwal, K. M. Thomas, R. J. Brosius, J. W. Davila, J. M. TI Fe XIII emission lines in active region spectra obtained with the Solar Extreme-Ultraviolet Research Telescope and Spectrograph SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE atomic data; Sun : activity; Sun : corona; Sun : UV radiation ID EUV-ROCKET-TELESCOPE; ELECTRON-IMPACT EXCITATION; OPTICALLY THIN PLASMAS; ATOMIC DATABASE; COLLISION STRENGTHS; SERTS; CHIANTI; IONS; SUN; ELEMENTS AB Recent fully relativistic calculations of radiative rates and electron impact excitation cross-sections for Fe XIII are used to generate emission-line ratios involving 3s(2)3p(2) - 3s3p(3) and 3s(2)3p(2) - 3s(2)3p3d transitions in the 170 - 225 and 235 - 450 angstrom wavelength ranges covered by the Solar Extreme-Ultraviolet Research Telescope and Spectrograph (SERTS). A comparison of these line ratios with SERTS active region observations from rocket flights in 1989 and 1995 reveals generally very good agreement between theory and experiment. Several new Fe XIII emission features are identified, at wavelengths of 203.79, 259.94, 288.56 and 290.81 angstrom. However, major discrepancies between theory and observation remain for several Fe XIII transitions, as previously found by Landi and others, which cannot be explained by blending. Errors in the adopted atomic data appear to be the most likely explanation, in particular for transitions which have 3s(2)3p3d D-1(2) as their upper level. The most useful Fe XIII electron-density diagnostics in the SERTS spectral regions are assessed, in terms of the line pairs involved being (i) apparently free of atomic physics problems and blends, (ii) close in wavelength to reduce the effects of possible errors in the instrumental intensity calibration, and (iii) very sensitive to changes in Ne over the range 10(8) - 10(11) cm(-3). It is concluded that the ratios which best satisfy these conditions are 200.03/202.04 and 203.17/202.04 for the 170 - 225 angstrom wavelength region, and 348.18/320.80, 348.18/368.16, 359.64/348.18 and 359.83/368.16 for 235 - 450 angstrom. C1 Queens Univ Belfast, Astrophys Res Ctr, Sch Math & Phys, Belfast BT7 1NN, Antrim, North Ireland. NASA, Goddard Space Flight Ctr, Lab Solar Phys, Heliophys Sci Div, Greenbelt, MD 20771 USA. Catholic Univ Amer, Dept Phys, Washington, DC 20064 USA. RP Keenan, FP (reprint author), Queens Univ Belfast, Astrophys Res Ctr, Sch Math & Phys, Belfast BT7 1NN, Antrim, North Ireland. EM F.Keenan@qub.ac.uk OI Jess, David/0000-0002-9155-8039 NR 35 TC 11 Z9 11 U1 0 U2 1 PU BLACKWELL PUBLISHING PI OXFORD PA 9600 GARSINGTON RD, OXFORD OX4 2DQ, OXON, ENGLAND SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD MAR 21 PY 2007 VL 376 IS 1 BP 205 EP 214 DI 10.1111/j.1365-2966.2006.11418.x PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 145TC UT WOS:000244886400032 ER PT J AU Kumar, P McMahon, E Panaitescu, A Willingale, R O'Brien, P Burrows, D Cummings, J Gehrels, N Holland, S Pandey, SB Berk, DV Zane, S AF Kumar, P. McMahon, E. Panaitescu, A. Willingale, R. O'Brien, P. Burrows, D. Cummings, J. Gehrels, N. Holland, S. Pandey, S. B. Berk, D. Vanden Zane, S. TI The nature of the outflow in gamma-ray bursts SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE gamma-rays : bursts; gamma-rays : theory ID AFTERGLOW EMISSION; MAGNETIC-FIELDS; LIGHT-CURVE; FIREBALLS; PULSARS; PROMPT; MODEL AB The Swift satellite has enabled us to follow the evolution of gamma-ray burst (GRB) fireballs from the prompt gamma-ray emission to the afterglow phase. The early-time X-ray and optical data for GRBs obtained by telescopes aboard the Swift satellite show that the source for prompt gamma-ray emission, the emission that heralds these bursts, is short lived, and is distinct from the source for the long-lived afterglow emission that follows the initial burst. Using these data we determine the distance of the gamma-ray source from the centre of the explosion. We find this distance to be 10(15)-10(16) cm for most bursts, and show that this is within a factor of about 10 of the radius of the shock heated circumstellar medium (CSM) producing the X-ray photons. Furthermore, using the early gamma-ray, X-ray and optical data we show that the prompt gamma-ray emission cannot be produced in internal shocks nor can it be produced in the external shock; in a more general sense gamma-ray generation mechanisms based on shock physics have problems explaining the GRB data for ten Swift bursts analyzed in this work. A magnetic field dominated outflow model for GRBs has a number of attractive features, although evidence in its favour is inconclusive. Finally, the X-ray and optical data allow us to provide an upper limit on the density of the CSM of about 10 protons cm(-3) at a distance of similar to 5 x 10(16) cm from the centre of explosion. C1 Univ Texas, Dept Astron, Austin, TX 78712 USA. Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Univ Leicester, Dept Phys & Astron, Leicester LE1 7RH, Leics, England. Penn State Univ, Dept Astron & Astrophys, University Pk, PA 16802 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. UCL, Mullard Space Sci Lab, Dorking RH5 6NT, Surrey, England. RP Kumar, P (reprint author), Univ Texas, Dept Astron, RLM 15308, Austin, TX 78712 USA. EM pk@astro.as.utexas.edu; emcmahon@astro.as.utexas.edu RI Gehrels, Neil/D-2971-2012 NR 23 TC 37 Z9 38 U1 0 U2 1 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD MAR 21 PY 2007 VL 376 IS 1 BP L57 EP L61 DI 10.1111/j.1365-2966.2007.00286.x PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 145TC UT WOS:000244886400013 ER PT J AU Menut, JL Gendron, E Schartmann, M Tuthill, P Lopez, B Danchi, WC Wolf, S Lagrange, AM Flament, S Rouan, D Clenet, Y Berruyer, N AF Menut, J. -L. Gendron, E. Schartmann, M. Tuthill, P. Lopez, B. Danchi, W. C. Wolf, S. Lagrange, A. -M. Flament, S. Rouan, D. Clenet, Y. Berruyer, N. TI The carbon star IRC+10216: linking the complex inner region with its spherical large-scale structures SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE instrumentation : adaptive optics; stars : AGB and post-AGB; circumstellar matter; infrared : stars ID CONTINUUM RADIATIVE-TRANSFER; MONTE-CARLO METHOD; CIRCUMSTELLAR ENVELOPE; DUST; INTERFEROMETRY; EMISSION; MODEL; IRAS; VLT AB IRC+10216 is located at the tip of the asymptotic giant branch of the Hertzsprung-Russell diagram in a transition phase toward the post-asymptotic giant branch stage. Its study contributes to our knowledge of the late stage of stellar evolution of low- and intermediate-mass stars, when the circumstellar matter begins to adopt the asymmetric or bipolar forms commonly found in planetary nebulae. Using the NAOS-CONICA (NACO) adaptive optics system, we have mapped the circumstellar environment of IRC+1O216 at several wavelengths and three different epochs. The NACO study provides high-resolution and high-dynamic-range information on the different features displayed by the circumstellar envelope: clumpiness and a peanut- or bipolar-like shape at small scales. The link between the inner regions and the spherical-like shells observed at large scales is displayed in these high-dynamic-range data. C1 Observ Cote Azur, Gemini, F-06304 Nice, France. Observ Paris, LESIA, F-92195 Meudon, France. Max Planck Inst Astron, D-69117 Heidelberg, Germany. Univ Sydney, Sch Phys, Sydney, NSW 2006, Australia. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Observ Grenoble, Astrophys Lab, F-38041 Grenoble, France. RP Menut, JL (reprint author), Observ Cote Azur, Gemini, F-06304 Nice, France. EM menut@obs-nice.fr NR 23 TC 12 Z9 12 U1 0 U2 0 PU BLACKWELL PUBLISHING PI OXFORD PA 9600 GARSINGTON RD, OXFORD OX4 2DQ, OXON, ENGLAND SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD MAR 21 PY 2007 VL 376 IS 1 BP L6 EP L10 DI 10.1111/j.1745-3933.2006.00274.x PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 145TC UT WOS:000244886400002 ER PT J AU Sidick, E Wilson, DW AF Sidick, Erkin Wilson, Daniel W. TI Behavior of imperfect band-limited coronagraphic masks in a high-contrast imaging system SO APPLIED OPTICS LA English DT Article AB We investigate the behavior of imperfect band-limited occulting masks in a high-contrast imaging system through modeling and simulations. Grayscale masks having 1D Sinc(2) (linear-Sinc(2)) amplitude transmission coefficient (Sinc(2) intensity transmittance) profiles as well as optical density and wavelength-dependent parasitic phases are considered occulters. We compare the behaviors of several, slightly different occulter transmittance profiles by evaluating the contrast performance of the high-contrast imaging testbed (HCIT) at the Jet Propulsion Laboratory (JPL). These occulters include a measured occulter, a standard Sinc(2) occulter, and several of its variations. We show that when an occulting mask has a parasitic phase, a modified Sinc(2) transmittance profile works much better than the standard Sinc(2) mask. We examine the impact of some fabrication errors of the occulter on the HCIT's contrast performance. We find through modeling and simulations that starlight suppression by a factor of more than 10(10) is achievable at least monochromatically on the HCIT with the occulting mask and the optics currently being used on the testbed. To the best of our knowledge, this is the first time that we investigate the behavior of a real (or fabricated) focal plane occulting mask in a high-contrast imaging system. We also briefly describe the approach used at JPL in fabricating a grayscale occulting mask and characterizing its transmittance and phase profiles. (c) 2007 Optical Society of America. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Sidick, E (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM erkin.sidick@jpl.nasa.gov NR 12 TC 6 Z9 6 U1 0 U2 0 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1559-128X EI 2155-3165 J9 APPL OPTICS JI Appl. Optics PD MAR 20 PY 2007 VL 46 IS 9 BP 1397 EP 1407 DI 10.1364/AO.46.001397 PG 11 WC Optics SC Optics GA 146PC UT WOS:000244945500004 PM 17334428 ER PT J AU Zhang, KX Li, W Stamnes, K Eide, H Spurr, R Tsay, SC AF Zhang, Kexin Li, Wei Stamnes, Knut Eide, Hans Spurr, Robert Tsay, Si-Chee TI Assessment of the Moderate-Resolution Imaging Spectroradiometer algorithm for retrieval of aerosol parameters over the ocean SO APPLIED OPTICS LA English DT Article ID ATMOSPHERIC CORRECTION; RADIATIVE-TRANSFER; OPTICAL-PROPERTIES; SIZE DISTRIBUTION; COLOR IMAGERY; LAYERED MEDIA; SYSTEM; RADIANCE; ACCURATE; SCATTERING AB The Moderate Resolution Imaging Spectroradiometer aerosol algorithm over the ocean derives spectral aerosol optical depth and aerosol size parameters from satellite measured radiances at the top of the atmosphere (TOA). It is based on the adding of apparent optical properties (AOPs): TOA reflectance is approximated as a linear combination of reflectances resulting from a small particle mode and a large particle mode. The weighting parameter eta is defined as the fraction of the optical depth at 550 nm due to the small mode. The AOP approach is correct only in the single scattering limit. For a physically correct TOA reflectance simulation, we create linear combinations of the inherent optical properties (IOPs) of small and large particle modes, in which the weighting parameter f is defined as the fraction of the number density attributed to the small particle mode. We use these IOPs as inputs to an accurate multiple scattering radiative transfer model. We find that reflectance errors incurred with the AOP method are as high as 30% for an aerosol optical depth of 2 at 550 run. The retrieved optical depth has a relative error of up to 8%, and the retrieved fraction eta has an absolute error of similar to 6%. We show that the use of accurate radiative transfer simulations and a bimodal fraction f yields accurate values for the retrieved optical depth and the fraction f. (c) 2007 Optical Society of America. C1 Stevens Inst Technol, Dept Phys & Engn Phys, Light & Life Lab, Hoboken, NJ 07030 USA. RT Solut Inc, Cambridge, MA 02138 USA. NASA, Goddard Space Flight Ctr, Earth Sci Directorate, Greenbelt, MD 20771 USA. RP Zhang, KX (reprint author), Stevens Inst Technol, Dept Phys & Engn Phys, Light & Life Lab, Hoboken, NJ 07030 USA. EM kzhang@stevens.edu RI Tsay, Si-Chee/J-1147-2014 NR 28 TC 7 Z9 8 U1 1 U2 1 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1559-128X EI 2155-3165 J9 APPL OPTICS JI Appl. Optics PD MAR 20 PY 2007 VL 46 IS 9 BP 1525 EP 1534 DI 10.1364/AO.46.001525 PG 10 WC Optics SC Optics GA 146PC UT WOS:000244945500021 PM 17334445 ER PT J AU Helmboldt, JF Taylor, GB Tremblay, S Fassnacht, CD Walker, RC Myers, ST Sjouwerman, LO Pearson, TJ Readhead, ACS Weintraub, L Gehrels, N Romani, RW Healey, S Michelson, PF Blandford, RD Cotter, G AF Helmboldt, J. F. Taylor, G. B. Tremblay, S. Fassnacht, C. D. Walker, R. C. Myers, S. T. Sjouwerman, L. O. Pearson, T. J. Readhead, A. C. S. Weintraub, L. Gehrels, N. Romani, R. W. Healey, S. Michelson, P. F. Blandford, R. D. Cotter, G. TI The VLBA imaging and polarimetry survey at 5 GHz SO ASTROPHYSICAL JOURNAL LA English DT Article DE catalogs; galaxies : active; galaxies : jets; galaxies : nuclei; radio continuum : galaxies; surveys; techniques : image processingt ID ACTIVE GALACTIC NUCLEI; DIGITAL-SKY-SURVEY; COMPLETE SAMPLE; RADIO-SOURCES; DATA RELEASE; POLARIZATION; QUASARS; OBJECTS AB We present the first results of the VLBA Imaging and Polarimetry Survey (VIPS), a 5 GHz VLBI survey of 1127 sources with flat radio spectra. Through automated data reduction and imaging routines, we have produced publicly available I, Q, and U images and have detected polarized flux density from 37% of the sources. We have also developed an algorithm to use each source's I image to automatically classify it as a pointlike source, a core jet, a compact symmetric object (CSO) candidate, or a complex source. Using data from the Sloan Digital Sky Survey (SDSS), we have found no significant trend between optical flux and 5 GHz flux density for any of the source categories. Using the velocity width of the H beta emission line and the monochromatic luminosity at 5100 angstrom to estimate the central black hole mass, M-BH, we have found a weak trend between MBH and 5 GHz luminosity density for objects with SDSS spectra. The mean ratio of the polarized to total 5 GHz flux density for VIPS sources with detected polarized flux density ranges from 1% to 20% with a median value of about 5%. We have also found significant evidence that the directions of the jets in core-jet systems tend to be perpendicular to the electric vector position angles (EVPAs). The data are consistent with a scenario in which similar to 24% of the polarized core jets have EVPAs that are antialigned with the directions of their jet components and that have a substantial amount of Faraday rotation. In addition to these initial results, plans for future follow-up observations are discussed. C1 Univ New Mexico, Dept Phys & Astron, Albuquerque, NM 87131 USA. Univ Calif Davis, Dept Phys, Davis, CA 95616 USA. Natl Radio Astron Observ, Socorro, NM 87801 USA. CALTECH, Dept Astron, Pasadena, CA 91125 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Stanford Univ, Dept Phys, Stanford, CA 94305 USA. Stanford Univ, KIPAC, Stanford, CA 94305 USA. Univ Oxford, Dept Astrophys, Oxford OX1 3RH, England. RP Helmboldt, JF (reprint author), Univ New Mexico, Dept Phys & Astron, Albuquerque, NM 87131 USA. RI Helmboldt, Joseph/C-8105-2012; Gehrels, Neil/D-2971-2012; Tremblay, Steven/C-1617-2013; Pearson, Timothy/N-2376-2015 OI Pearson, Timothy/0000-0001-5213-6231 NR 24 TC 82 Z9 83 U1 2 U2 6 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAR 20 PY 2007 VL 658 IS 1 BP 203 EP 216 DI 10.1086/511005 PN 1 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 146IY UT WOS:000244928900016 ER PT J AU Cohen, MH Lister, ML Homan, DC Kadler, M Kellermann, KI Kovalev, YY Vermeulen, RC AF Cohen, M. H. Lister, M. L. Homan, D. C. Kadler, M. Kellermann, K. I. Kovalev, Y. Y. Vermeulen, R. C. TI Relativistic beaming and the intrinsic properties of extragalactic radio jets SO ASTROPHYSICAL JOURNAL LA English DT Article DE BL Lacertae objects : general; galaxies : active; galaxies : individual (Cygnus A); galaxies : jets; galaxies : statistics; quasars : general ID ACTIVE GALACTIC NUCLEI; SUPERLUMINAL SOURCES; VARIABILITY; QUASARS; FLUX; GHZ; KINEMATICS; VELOCITY; GALAXIES; SPECTRA AB Relations between the observed quantities for a beamed radio jet, which are the apparent transverse speed and the apparent luminosity (beta(app), L), and the intrinsic quantities, which are the Lorentz factor and the intrinsic luminosity (gamma, L-0), are investigated. The inversion from measured to intrinsic values is not unique, but approximate limits to gamma and L-0 can be found using probability arguments. Roughly half the sources in a flux density-limited, beamed sample have a value of gamma close to the measured value of beta(app). The methods are applied to observations of 119 AGN jets made with the VLBA at 15 GHz during 1994-2002. The results strongly support the common relativistic beam model for an extragalactic radio jet. The (beta(app), L) data are closely bounded by a theoretical envelope, an ''aspect'' curve for gamma = 32 and L-0 10(25) W Hz(-1). This gives limits to the maximum values of gamma and L-0 in the sample: gamma(max) approximate to 32, and L-0,L-max similar to 10(26) W Hz(-1). No sources with both high values of beta(app) and low values of L are observed. This is not the result of selection effects due to the observing limits, which are a flux density of S > 0.5 Jy and an angular velocity of mu < 4 mas yr(-1). Many of the fastest quasars have a pattern Lorentz factor, gamma(p), that is close to that of the beam, gamma(b), but some of the slow quasars must have gamma(p)<< gamma(b). Three of the 10 galaxies in the sample have a superluminal feature, with speeds up to beta(app) approximate to 6. The others are at most mildly relativistic. The galaxies are not off-axis versions of the powerful quasars, but Cygnus A might be an exception. C1 [Cohen, M. H.] CALTECH, Dept Astron, Pasadena, CA 91125 USA. [Lister, M. L.] Purdue Univ, Dept Phys, W Lafayette, IN 47907 USA. [Homan, D. C.] Denison Univ, Dept Phys & Astron, Granville, OH 43023 USA. [Kadler, M.] NASA, Goddard Space Flight Ctr, Ctr Astrophys Sci, Greenbelt, MD 20771 USA. [Kadler, M.; Kovalev, Y. Y.] Max Planck Inst Radioastron, D-5300 Bonn, Germany. [Kellermann, K. I.] Natl Radio Astron Observ, Charlottesville, VA USA. [Kovalev, Y. Y.] PN Lebedev Phys Inst, Ctr Astro Space, Moscow 117924, Russia. [Vermeulen, R. C.] Netherlands Fdn Res Astron, ASTRON, NL-7990 AA Dwingeloo, Netherlands. RP Cohen, MH (reprint author), CALTECH, Dept Astron, Pasadena, CA 91125 USA. EM mhc@astro.caltech.edu; mlister@physics.purdue.edu; homand@denison.edu; mkadler@milkyway.gsfc.nasa.gov; kkellerm@nrao.edu; ykovalev@mpifr-bonn.mpg.de; rvermeulen@astron.nl RI Kovalev, Yuri/J-5671-2013; OI Kovalev, Yuri/0000-0001-9303-3263; Kadler, Matthias/0000-0001-5606-6154 NR 39 TC 76 Z9 76 U1 0 U2 4 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X EI 1538-4357 J9 ASTROPHYS J JI Astrophys. J. PD MAR 20 PY 2007 VL 658 IS 1 BP 232 EP 244 DI 10.1086/511063 PN 1 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 146IY UT WOS:000244928900018 ER PT J AU Clark, DM Eikenberry, SS Brandl, BR Wilson, JC Carson, JC Henderson, CP Hayward, TL Barry, DJ Ptak, AF Colbert, EJM AF Clark, D. M. Eikenberry, S. S. Brandl, B. R. Wilson, J. C. Carson, J. C. Henderson, C. P. Hayward, T. L. Barry, D. J. Ptak, A. F. Colbert, E. J. M. TI Infrared counterparts to Chandra X-ray sources in the antennae SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : starburst; galaxies : star clusters; X-rays : binaries ID HIGH-RESOLUTION IMAGER; GALAXIES NGC-4038/4039; NGC 4038/4039; CLUSTERS; POPULATION AB We use deep J (1.25 mu m) and Ks (2.15 mu m) images of the Antennae (NGC 4038/ 4039) obtained with the Wide-field InfraRed Camera on the Palomar 200 inch (5 m) telescope, together with the Chandra X-ray source list of Zezas and coworkers to search for infrared counterparts to X-ray point sources. We establish an X-ray/ IR astrometric frame tie with similar to 0.5" rms residuals over a similar to 4.3' field. We find 13 "strong'' IR counterparts brighter than K-s = 17.8 mag and < 1.0" from X-ray sources, and an additional 6 "possible'' IR counterparts between 1.0" and 1.5" from X-ray sources. Based on a detailed study of the surface density of IR sources near the X-ray sources, we expect only similar to 2 of the "strong'' counterparts and similar to 3 of the "possible'' counterparts to be chance superpositions of unrelated objects. Comparing both strong and possible IR counterparts to our photometric study of similar to 220 IR clusters in the Antennae, we find with a > 99.9% confidence level that IR counterparts to X-ray sources are Delta M-Ks similar to 1.2 mag more luminous than average non-X-ray clusters. We also note that the X-ray/ IR matches are concentrated in the spiral arms and "overlap'' regions of the Antennae. This implies that these X-ray sources lie in the most "super'' of the Antennae's super star clusters, and thus trace the recent massive star formation history here. Based on the N-H inferred from the X-ray sources without IR counterparts, we determine that the absence of most of the "missing'' IR counterparts is not due to extinction, but that these sources are intrinsically less luminous in the IR, implying that they trace a different (possibly older) stellar population. We find no clear correlation between X-ray luminosity classes and IR properties of the sources, although small-number statistics hamper this analysis. C1 Univ Florida, Dept Astron, Gainesville, FL 32611 USA. Leiden Observ, NL-2300 RA Leiden, Netherlands. Univ Virginia, Dept Astron, Charlottesville, VA 22903 USA. Jet Propuls Lab, Pasadena, CA USA. Cornell Univ, Dept Astron, Ithaca, NY 14853 USA. AURA, Gemini Observ, La Serena, Chile. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. RP Clark, DM (reprint author), Univ Florida, Dept Astron, Gainesville, FL 32611 USA. EM dmclark@astro.ufl.edu RI Ptak, Andrew/D-3574-2012 NR 27 TC 7 Z9 7 U1 0 U2 3 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAR 20 PY 2007 VL 658 IS 1 BP 319 EP 327 DI 10.1086/511511 PN 1 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 146IY UT WOS:000244928900026 ER PT J AU Sahai, R Contreras, CS Morris, M Claussen, M AF Sahai, Raghvendra Sanchez Contreras, Carmen Morris, Mark Claussen, Mark TI A quadrupolar preplanetary nebula: IRAS 19475+3119 SO ASTROPHYSICAL JOURNAL LA English DT Article DE circumstellar matter; dust, extinction; planetary nebulae : general stars : AGB and post-AGB; stars : mass loss; stars : individual (IRAS 19475+3119) ID PROTOPLANETARY NEBULAE; PLANETARY-NEBULAE; CIRCUMSTELLAR ENVELOPES; ACCRETION DISKS; BINARY-SYSTEMS; DUST GRAINS; AGB STARS; MASS-LOSS; WINDS; HYDRODYNAMICS AB Our imaging of the preplanetary nebula IRAS 19475+3119 ( hereafter I19475) at 0.43 and 0.6 mu m with HST reveals a quadrupolar nebula of size about 10: 500; 4: 700, with two bipolar elongated lobes emanating from the center of the nebula. One of the bipolar lobes shows detailed point-symmetric structure with respect to the central star. A faint, surface brightness-limited, diffuse halo surrounds the lobes. Interferometric observations of the CO J = 1-0 line with OVRO at similar to 8" resolution show that the bulk of the emission comes from an unresolved molecular envelope expanding at 15 km s(-1), resulting from the AGB progenitor's dense, slow wind. Weaker emission is seen from a fast bipolar outflow oriented along the longer and more tenuous pair of the sets of lobes. Optical spectroscopy reveals a complex H alpha profile with a broad photospheric absorption feature and a narrow inverse P Cygni shaped core; comparison with previous data shows that the core profile shape varies dramatically with time. We find an unresolved source of millimeter-wave continuumemission in I19475, which together with previous submillimeter continuummeasurements, implies a very substantial mass ( roughly a few times 0.01M(circle dot)) of large ( radius greater than or similar to 1mm), cold (similar to 30 K) dust grains in I19475. Combining our estimates of the circumstellar mass with the typical mass of a post-AGB star, we find that the main-sequence progenitor of I19475' s central star had a mass greater than or similar to 2.5 M-circle dot. We discuss the formation of I19475' s quadrupolar nebula in the light of past and current ideas for the dramatic transformation of the morphology and kinematics of mass ejecta as AGB stars evolve into planetary nebulae. C1 CALTECH, Jet Propuls Lab, Pasadena, CA 91125 USA. Univ Calif Los Angeles, Dept Phys & Astrophys, Div Astron, Los Angeles, CA USA. Natl Radio Astron Observ, Socorro, NM 87801 USA. RP Sahai, R (reprint author), CALTECH, Jet Propuls Lab, Pasadena, CA 91125 USA. EM raghvendra.sahai@jpl.nasa.gov RI Sanchez-Contreras, Carmen/N-3718-2015 OI Sanchez-Contreras, Carmen/0000-0002-6341-592X NR 34 TC 17 Z9 17 U1 0 U2 3 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X EI 1538-4357 J9 ASTROPHYS J JI Astrophys. J. PD MAR 20 PY 2007 VL 658 IS 1 BP 410 EP 422 DI 10.1086/511294 PN 1 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 146IY UT WOS:000244928900034 ER PT J AU Rutledge, RE Bildsten, L Brown, EF Chakrabarty, D Pavlov, GG Zavlin, VE AF Rutledge, Robert E. Bildsten, Lars Brown, Edward F. Chakrabarty, Deepto Pavlov, George G. Zavlin, Vyacheslav E. TI Pulsations detected from accreting high-mass X-ray binaries at low luminosities SO ASTROPHYSICAL JOURNAL LA English DT Article DE pulsars : general; pulsars : individual (4U 1145-619, 1A 1118-615) ID MAGNETIZED NEUTRON-STARS; SPECTRAL VARIABILITY; STELLAR WIND; 4U 1145-619; HE 3-640; PULSAR; TRANSIENT; EMISSION; QUIESCENCE; OUTBURST AB We report the detection of pulsations from two accreting transient high-mass X-ray binaries (HMXBs) at low X-ray luminosities (approximate to 1-4 x 10(34) ergs s(-1)). While one (4U 1145 - 619) has been detected pulsing previously at a lower luminosity, the second (1A 1118 - 615) has not, making it the third such transient HMXB from which pulsations are detected at low luminosity. The pulsars exhibit broadband rms variability (22.3% +/- 0.1% and 9.2% +/- 0.1%, respectively). While the present observations do not permit measurement of a spin frequency derivative, spin-down is implied in comparison with previous Compton Gamma Ray Observatory/BATSE observations. If spin-down occurred at the presently observed X-ray luminosity of 4U 1145 - 619, the required mass accretion rate is insufficient to produce the observed X-ray luminosity from a shock at the magnetosphere, and only a fraction of the mass accretion makes its way to the neutron star surface, with most of the mass leaving the system, carrying away angular momentum to affect spin-down. C1 McGill Univ, Dept Phys, Montreal, PQ, Canada. Univ Calif Santa Barbara, Kavli Inst Theoret Phys, Santa Barbara, CA 93106 USA. Univ Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USA. Michigan State Univ, Dept Phys & Astron, E Lansing, MI 48824 USA. MIT, Dept Phys, Cambridge, MA 02139 USA. MIT, Ctr Space Res, Cambridge, MA 02139 USA. Penn State Univ, University Pk, PA 16802 USA. NASA, MSFC, Space Sci Lab, Huntsville, AL USA. RP Rutledge, RE (reprint author), McGill Univ, Dept Phys, 3600 Univ St, Montreal, PQ, Canada. EM rutledge@physics.mcgill.ca; bildsten@kitp.ucsb.edu; ebrown@pa.msu.edu; deepto@space.mit.edu; pavlov@astro.psu.edu; vyacheslav.zavlin@nasa.msfc.gov RI Brown, Edward/F-1721-2011; OI Brown, Edward/0000-0003-3806-5339 NR 38 TC 16 Z9 16 U1 0 U2 2 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAR 20 PY 2007 VL 658 IS 1 BP 514 EP 519 DI 10.1086/510183 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 146IY UT WOS:000244928900043 ER PT J AU Lane, BF Sokoloski, JL Barry, RK Traub, WA Retter, A Muterspaugh, MW Thompson, RR Eisner, JA Serabyn, E Mennesson, B AF Lane, B. F. Sokoloski, J. L. Barry, R. K. Traub, W. A. Retter, A. Muterspaugh, M. W. Thompson, R. R. Eisner, J. A. Serabyn, E. Mennesson, B. TI Interferometric observations of RS Ophiuchi and the origin of the near-infrared emission SO ASTROPHYSICAL JOURNAL LA English DT Article DE techniques : interferometric ID PALOMAR TESTBED INTERFEROMETER; 2006 OUTBURST; NOVA OUTBURSTS; OPTICALLY THICK; RECURRENT NOVAE; IA SUPERNOVAE; SYSTEMS; PHASE; MODELS; STARS AB We report observations of the recurrent nova RS Oph using long-baseline near-IR interferometry. We are able to resolve emission from the nova for several weeks after the 2006 February outburst. The near-IR source initially expands to a size of similar to 5 mas. However, beginning around day 10, the IR source appears to begin to shrink, reaching similar to 2 mas by day 100. We combine our measured angular diameters with previously available interferometric and photometric data to derive an emission measure for the source, and hence are able to determine the mass-loss rate of the nova in the days following the outburst. C1 MIT, Dept Phys, Kavli Inst Astrophys & Space Res, Cambridge, MA 02139 USA. Smithsonian Astrophys Observ, Cambridge, MA USA. Johns Hopkins Univ, Baltimore, MD USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Jet Propuls Lab, Pasadena, CA USA. Penn State Univ, Dept Astron & Astrophys, University Pk, PA 16802 USA. Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. CALTECH, Michelson Sci Ctr, Pasadena, CA 91125 USA. Univ Calif Berkeley, Berkeley, CA 94720 USA. RP Lane, BF (reprint author), MIT, Dept Phys, Kavli Inst Astrophys & Space Res, Cambridge, MA 02139 USA. EM blane@mit.edu; jsokolos@cfa.harvard.edu; retter@astro.psu.edu; thompson@ipac.caltech.edu NR 37 TC 21 Z9 21 U1 0 U2 4 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAR 20 PY 2007 VL 658 IS 1 BP 520 EP 524 DI 10.1086/511414 PN 1 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 146IY UT WOS:000244928900044 ER PT J AU Wyatt, MC Smith, R Greaves, JS Beichman, CA Bryden, G Lisse, CM AF Wyatt, M. C. Smith, R. Greaves, J. S. Beichman, C. A. Bryden, G. Lisse, C. M. TI Transience of hot dust around Sun-like stars SO ASTROPHYSICAL JOURNAL LA English DT Article DE circumstellar matter; planetary systems : formation ID TERRESTRIAL PLANET FORMATION; EDGEWORTH-KUIPER BELT; MAIN-SEQUENCE STARS; OUTER SOLAR-SYSTEM; SIZE DISTRIBUTION; ASTEROID BELT; DEBRIS DISKS; VEGA PHENOMENON; AGE-DEPENDENCE; BETA-PICTORIS AB In this paper a simple model for the steady state evolution of debris disks due to collisions is developed and confronted with the properties of the emerging population of seven Sun-like stars that have hot dust at < 10 AU. The model shows that there is a maximum possible disk mass at a given age, since more massive primordial disks process their mass faster. The corresponding maximum dust luminosity is f(max) = 0.16; 10(-3)r(7/3)t(age)(-1) age, where r is disk radius in AU and t(age) is system age in Myr. The majority (4/7) of the hot disks exceed this limit by >> 1000 and so cannot be the products of massive asteroid belts; rather, the following systems must be undergoing transient events characterized by an unusually high dust content near the star: eta Corvi, HD 69830, HD 72905, and BD + 20 307. It is also shown that the hot dust cannot originate in a recent collision in an asteroid belt, since there is also a maximum rate at which collisions of sufficient magnitude to reproduce a given dust luminosity can occur. The planetesimal belt feeding the dust in these systems must be located farther from the star than the dust, typically at >> 2 AU. Other notable properties of the four hot dust systems are as follows: two also have a planetesimal belt at > 10 AU (eta Corvi and HD 72905); one has three Neptune mass planets at < 1 AU (HD 69830); all exhibit strong mid-IR silicate features. We consider the most likely origin for this transient dust to be a dynamical instability that scattered planetesimals inward from a more distant planetesimal belt in an event akin to the late heavy bombardment in our own system, the dust being released from such planetesimals in collisions and sublimation. C1 Univ Cambridge, Inst Astron, Cambridge CB3 0HA, England. Royal Observ, Inst Astron, Edinburgh EH9 3HJ, Midlothian, Scotland. Univ St Andrews, Scottish Univ Phys Allicance, St Andrews, Fife, Scotland. Jet Propuls Lab, Pasadena, CA USA. Johns Hopkins Univ, Appl Phys Lab, Dept Space, Planetary Explorat Grp, Laurel, MD USA. RP Wyatt, MC (reprint author), Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England. RI Lisse, Carey/B-7772-2016 OI Lisse, Carey/0000-0002-9548-1526 NR 62 TC 165 Z9 166 U1 1 U2 4 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAR 20 PY 2007 VL 658 IS 1 BP 569 EP 583 DI 10.1086/510999 PN 1 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 146IY UT WOS:000244928900049 ER PT J AU Lisse, CM Beichman, CA Bryden, G Wyatt, MC AF Lisse, C. M. Beichman, C. A. Bryden, G. Wyatt, M. C. TI On the nature of the dust in the debris disk around HD 69830 SO ASTROPHYSICAL JOURNAL LA English DT Article DE comets : general; infrared : general; minor planets, asteroids; techniques : spectroscopic ID MAIN-SEQUENCE STARS; ASTEROID BELT; PLANETARY SYSTEM; DEEP IMPACT; COMETS; SOLAR; COLLISIONS; EVOLUTION; TEMPEL-1; ORIGIN AB We have used the infrared mineralogical model derived from the Spitzer IRS observations of the Deep Impact experiment to study the nature of the dust in the debris found around the K0 V star HD 69830. Using a robust approach to determine the bulk average mineralogical composition of the dust, we show it to be substantially different from that found for comets 9P/Tempel 1 and C/Hale-Bopp 1995 O1 or for the comet-dominated YSO HD 100546. Lacking in carbonaceous and ferrous materials but including small icy grains, the composition of the HD 69830 dust most closely resembles that of a disrupted P- or D- type asteroid. The amount of mass responsible for the observed emission is the equivalent of a 30 km radius, 2500 kg m(-3) sphere, while the radiative temperature of the dust implies that the bulk of the observed material is at similar to 1.0 AU from the central source, coincident with the 2:1 and 5:2 mean motion resonances of the outermost of three Neptune-sized planets detected by Lovis and coworkers. In our solar system, P- and D-type asteroids are both large and numerous in the outer main belt and near Jupiter ( e. g., the Hildas and Trojans) and have undergone major disruptive events to produce debris disk-like structures ( cf. the Karin and Veritas families 5-8 Myr ago). The short-lived nature of the small and icy dust implies that the disruption occurred within the last year, or that replenishment due to ongoing collisional fragmentation is occurring. C1 Johns Hopkins Univ, Appl Phys Lab, Dept Space, Planetary Explorat Grp, Laurel, MD USA. CALTECH, Michelson Sci Ctr, Pasadena, CA 91125 USA. Jet Propuls Lab, Pasadena, CA USA. Univ Cambridge, Inst Astron, Cambridge CB3 0HA, England. RP Lisse, CM (reprint author), Johns Hopkins Univ, Appl Phys Lab, Dept Space, Planetary Explorat Grp, Johns Hopkins Rd, Laurel, MD USA. EM carey.lisse@jhuapl.edu; chas@pop.jpl.nasa.gov; geoffrey.bryden@jpl.nasa.gov; wyatt@ast.cam.ac.uk RI Lisse, Carey/B-7772-2016 OI Lisse, Carey/0000-0002-9548-1526 NR 33 TC 67 Z9 67 U1 0 U2 3 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAR 20 PY 2007 VL 658 IS 1 BP 584 EP 592 DI 10.1086/511001 PN 1 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 146IY UT WOS:000244928900050 ER PT J AU Kaltenegger, L Traub, WA Jucks, KW AF Kaltenegger, Lisa Traub, Wesley A. Jucks, Kenneth W. TI Spectral evolution of an Earth-like planet SO ASTROPHYSICAL JOURNAL LA English DT Article DE astrobiology; Earth; planetary systems ID EXTRASOLAR TERRESTRIAL PLANETS; PROTEROZOIC OCEAN CHEMISTRY; ARCHEAN SULFUR CYCLE; ATMOSPHERIC OXYGEN; THERMAL EMISSION; LIFE; DARWIN; STARS; MODEL; BIOSIGNATURES AB We have developed a characterization of the geological evolution of the Earth's atmosphere and surface in order to model the observable spectra of an Earth-like planet through its geological history. These calculations are designed to guide the interpretation of an observed spectrum of such a planet by future instruments that will characterize exoplanets. Our models focus on planetary environmental characteristics whose resultant spectral features can be used to imply habitability or the presence of life. These features are generated by H2O, CO2, CH4, O-2, O-3, N2O, and vegetation- like surface albedos. We chose six geological epochs to characterize. These epochs exhibit a wide range in abundance for these molecules, ranging from a CO2-rich early atmosphere, to a CO2/CH4-rich atmosphere around 2 billion years ago, to a present-day atmosphere. We analyzed the spectra to quantify the strength of each important spectral feature in both the visible and thermal infrared spectral regions, and the resolutions required to optimally detect the features for each epoch. We find a wide range of spectral resolutions required for observing the different features. For example, H2O and O-3 can be observed with relatively low resolution, while O-2 and N2O require higher resolution. We also find that the inclusion of clouds in our models significantly affects both the strengths of all spectral features and the resolutions required to observe all these. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Jet Propuls Lab, Pasadena, CA USA. RP Kaltenegger, L (reprint author), Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. EM lkaltenegger@cfa.harvard.edu NR 65 TC 121 Z9 123 U1 3 U2 26 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAR 20 PY 2007 VL 658 IS 1 BP 598 EP 616 DI 10.1086/510996 PN 1 PG 19 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 146IY UT WOS:000244928900052 ER PT J AU Abdo, AA Allen, B Berley, D Blaufuss, E Casanova, S Chen, C Coyne, DG Delay, RS Dingus, BL Ellsworth, RW Fleysher, L Fleysher, R Gebauer, I Gonzalez, MM Goodman, JA Hays, E Hoffman, CM Kolterman, BE Kelley, LA Lansdell, CP Linnemann, JT McEnery, JE Mincer, AI Moskalenko, IV Nemethy, P Noyes, D Ryan, JM Samuelson, FW Parkinson, PMS Schneider, M Shoup, A Sinnis, G Smith, AJ Strong, AW Sullivan, GW Vasileiou, V Walker, GP Williams, DA Xu, XW Yodh, GB AF Abdo, A. A. Allen, B. Berley, D. Blaufuss, E. Casanova, S. Chen, C. Coyne, D. G. Delay, R. S. Dingus, B. L. Ellsworth, R. W. Fleysher, L. Fleysher, R. Gebauer, I. Gonzalez, M. M. Goodman, J. A. Hays, E. Hoffman, C. M. Kolterman, B. E. Kelley, L. A. Lansdell, C. P. Linnemann, J. T. McEnery, J. E. Mincer, A. I. Moskalenko, I. V. Nemethy, P. Noyes, D. Ryan, J. M. Samuelson, F. W. Parkinson, P. M. Saz Schneider, M. Shoup, A. Sinnis, G. Smith, A. J. Strong, A. W. Sullivan, G. W. Vasileiou, V. Walker, G. P. Williams, D. A. Xu, X. W. Yodh, G. B. TI Discovery of TeV gamma-ray emission from the Cygnus region of the Galaxy SO ASTROPHYSICAL JOURNAL LA English DT Article DE acceleration of particles; cosmic rays; gamma rays : observations; pulsars : individual (G75.2+0.1) ID BACKGROUND REJECTION TECHNIQUE; COMPLETE CO SURVEY; GALACTIC PLANE; PSR J2021+3651; CRAB-NEBULA; MILKY-WAY; PULSAR; TELESCOPES; SPECTRUM; CATALOG AB The diffuse gamma radiation arising from the interaction of cosmic-ray particles with matter and radiation in the Galaxy is one of the few probes available to study the origin of the cosmic rays. Data from the Milagro gamma-ray observatory - a water Cerenkov detector that continuously views similar to 2 sr of the overhead sky - shows that the brightest extended region in the entire northern sky is the Cygnus region of the Galactic plane. The TeV image of the Cygnus region contains at least one new source, MGRO J2019 + 37, which is 10.9 sigma above the isotropic background, as well as correlations with the matter density in the region. However, the gamma-ray flux from the Cygnus region (after excluding MGRO J2019 + 37) as measured at similar to 12 TeV exceeds that predicted from a model of cosmic-ray production and propagation. This observation indicates the existence of either hard-spectrum cosmic-ray sources and/or unresolved sources of TeV gamma rays in the region. C1 Michigan State Univ, E Lansing, MI 48824 USA. Univ Calif Irvine, Irvine, CA USA. Univ Maryland, College Pk, MD 20742 USA. Los Alamos Natl Lab, Los Alamos, NM USA. Univ Calif Santa Cruz, Santa Cruz, CA 95064 USA. George Mason Univ, Fairfax, VA 22030 USA. NYU, New York, NY USA. Univ Karlsruhe, Inst Expt Kernphys, D-7500 Karlsruhe, Germany. Univ Nacl Autonoma Mexico, Inst Astron, Mexico City 04510, DF, Mexico. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Stanford Univ, Stanford, CA 94305 USA. Univ New Hampshire, Durham, NH 03824 USA. Ohio State Univ, Lima, OH 45804 USA. Max Planck Inst Extraterr Phys, D-37075 Garching, Germany. RP Abdo, AA (reprint author), Michigan State Univ, E Lansing, MI 48824 USA. RI Moskalenko, Igor/A-1301-2007; McEnery, Julie/D-6612-2012; Hays, Elizabeth/D-3257-2012; Casanova, Sabrina/J-8935-2013; OI Moskalenko, Igor/0000-0001-6141-458X; Casanova, Sabrina/0000-0002-6144-9122; Dingus, Brenda/0000-0001-8451-7450; Mincer, Allen/0000-0002-6307-1418 NR 33 TC 121 Z9 121 U1 0 U2 4 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAR 20 PY 2007 VL 658 IS 1 BP L33 EP L36 DI 10.1086/513696 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 146JD UT WOS:000244929400009 ER PT J AU Naze, Y Corcoran, MF Koenigsberger, G Moffat, AFJ AF Naze, Yael Corcoran, Michael F. Koenigsberger, Gloria Moffat, Anthony F. J. TI First detection of phase-dependent colliding wind X-ray emission outside the Milky Way SO ASTROPHYSICAL JOURNAL LA English DT Article DE Magellanic Clouds; stars : individual (HD 5980); stars : winds, outflows; stars : Wolf-Rayet; X-rays : binaries ID XMM-NEWTON OBSERVATIONS; SMALL-MAGELLANIC-CLOUD; BINARY HD-5980; NGC-346 FIELD; HD 5980; STARS; VARIABILITY; DISCOVERY; CLUSTER AB After having reported the detection of X-rays emitted by the peculiar system HD 5980, we assess here the origin of this high-energy emission from additional X-ray observations obtained with XMM-Newton. This research provides the first detection of apparently periodic X-ray emission from hot gas produced by the collision of winds in an evolved massive binary outside the Milky Way. It also provides the first X-ray monitoring of a luminous blue variable only years after its eruption and shows that the dominant source of the X-rays is not associated with the ejecta. After having reported the detection of X-rays emitted by the peculiar system HD 5980, we assess here the origin of this high-energy emission from additional X-ray observations obtained with XMM-Newton. This research provides the first detection of apparently periodic X-ray emission from hot gas produced by the collision of winds in an evolved massive binary outside the Milky Way. It also provides the first X-ray monitoring of a luminous blue variable only years after its eruption and shows that the dominant source of the X-rays is not associated with the ejecta. C1 Univ Liege, Inst Astrophys & Geophys, B-4000 Liege, Belgium. Univ Space Res Assoc, Columbia, MD 21044 USA. NASA, Goddard Space Flight Ctr, Ctr Space Sci & Technol, Greenbelt, MD 20771 USA. Univ Nacl Autonoma Mexico, Inst Ciencias Fis, Cuernavaca 62251, Morelos, Mexico. Univ Montreal, Dept Phys, Montreal, PQ H3C 3J7, Canada. Observ Astron Mt Megantic, Notre Dame Des Bois, PQ J0B 2E0, Canada. RP Naze, Y (reprint author), Univ Liege, Inst Astrophys & Geophys, B-4000 Liege, Belgium. EM naze@astro.ulg.ac.be; corcoran@milkyway.gsfc.nasa.gov; gloria@astroscu.unam.mx; moffat@ASTRO.UMontreal.CA OI Naze, Yael/0000-0003-4071-9346 NR 23 TC 15 Z9 15 U1 0 U2 3 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAR 20 PY 2007 VL 658 IS 1 BP L25 EP L28 DI 10.1086/513510 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 146JD UT WOS:000244929400007 ER PT J AU Vazquez, GA Hornschemeier, AE Colbert, E Roberts, TP Ward, MJ Malhotra, S AF Vazquez, Gerardo A. Hornschemeier, Ann E. Colbert, Edward Roberts, Timothy P. Ward, Martin J. Malhotra, Sangeeta TI Constraints on accretion in ultraluminous X-ray sources from Spitzer IRS observations of NGC 4485/4490: Infrared diagnostic diagrams SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : general; galaxies : individual (NGC 4485, NGC 4490) ID ANTENNAE GALAXIES NGC-4038/4039; MASS BLACK-HOLES; NEARBY GALAXIES; SPACE-TELESCOPE; STAR-FORMATION; EMISSION; SPECTROGRAPH; NUCLEAR; OBJECTS; GAS AB Constraining the astrophysical nature of ultraluminous X-ray (ULX) sources, which have X-ray luminosities exceeding 10(39) ergs s(-1), has been elusive due to the optical faintness of any counterparts. With high spectral resolution observations in the similar to 10-30 mu m wavelength range we have conducted an experiment to study six ULX sources in the NGC 4485/4490 galaxy pair. We have found that five of the six ULXs, based on mid-infrared spectral diagnostics, show the characteristic higher ionization features that are found in AGNs. The sixth source, ULX-1, is consistent with being a supernova remnant. The chief infrared spectral diagnostics used are the ratios of [S III]/[Si II] versus [Ne III]/[Ne II]. In two instances fits to the continuum and polycyclic aromatic hydrocarbon (PAH) features also indicate higher dust temperatures, which are characteristic of accreting sources. Overall, however, we find that the continuum is dominated by stellar processes, and the best diagnostic features are the emission lines. High spectral resolution studies in the mid-infrared thus appear to show great promise for determining the astrophysical nature of ULXs. C1 Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. NASA, Goddard Space Flight Ctr, Lab Xray Astrophys, Greenbelt, MD 20771 USA. Univ Durham, Dept Phys, Durham DH1 3LE, England. Arizona State Univ, Dept Phys & Astron, Tempe, AZ 85287 USA. RP Vazquez, GA (reprint author), Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. EM vazquez@pha.jhu.edu; annh@milkyway.gsfc.nasa.gov; colbert@jhu.edu; t.p.roberts@durham.ac.uk; m.ward@durham.ac.uk; sangeeta.malhotra@asu.edu NR 35 TC 6 Z9 6 U1 0 U2 3 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAR 20 PY 2007 VL 658 IS 1 BP L21 EP L24 DI 10.1086/513423 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 146JD UT WOS:000244929400006 ER PT J AU Minnis, P Huang, JP Lin, B Yi, YH Arduini, RF Fan, TF Ayers, JK Mace, GG AF Minnis, Patrick Huang, Jianping Lin, Bing Yi, Yuhong Arduini, Robert F. Fan, Tai-Fang Ayers, J. Kirk Mace, Gerald G. TI Ice cloud properties in ice-over-water cloud systems using Tropical Rainfall Measuring Mission (TRMM) visible and infrared scanner and TRMM Microwave Imager data SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID CIRRUS CLOUD; SATELLITE MICROWAVE; OPTICAL-PROPERTIES; RADIOMETER; ALGORITHM; LIQUID; OCEANS; MODIS; CERES; VIRS AB A multilayered cloud retrieval system (MCRS) is updated and used to estimate ice water path in maritime ice-over-water clouds using Visible and Infrared Scanner (VIRS) and Tropical Rainfall Measuring Mission (TRMM) Microwave Imager (TMI) measurements acquired over the Tropics between January and August 1998. Lookup tables of top-of-atmosphere 0.65-mu m reflectance are developed for ice-over-water cloud systems using radiative transfer calculations for various combinations of ice-over-water cloud layers. The liquid and ice water paths, LWP and IWP, respectively, are determined with the MCRS using these lookup tables with a combination of microwave ( MW), visible ( VIS), and infrared (IR) data. LWP, determined directly from the TMI MW data, is used to define the lower-level cloud properties to select the proper lookup table. The properties of the upper-level ice clouds, such as optical depth and effective size, are then derived using the Visible-Infrared Solar-infrared Split-Window technique (VISST), which matches the VIRS IR, 3.9 mu m, and VIS data to the multilayer cloud lookup table reflectances and a set of emittance parameterizations. Initial comparisons with surface-based radar retrievals suggest that this enhanced MCRS can significantly improve the accuracy and decrease the IWP in overlapped clouds by 42 and 13% compared to using the single-layer VISST and an earlier simplified MW-VIS-IR (MVI) differencing method, respectively, for ice-over-water cloud systems. The tropical distribution of ice-over-water clouds is the same as derived earlier from combined TMI and VIRS data, but the new values of IWP and optical depth are slightly larger than the older MVI values and exceed those of single-layered clouds by 7 and 11%, respectively. The mean IWP from the MCRS is 8-14% greater than that retrieved from radar retrievals of overlapped clouds over two surface sites, and the standard deviations of the differences are similar to those for single-layered clouds. Examples of a method for applying the MCRS over land without MW data yield similar differences with the surface retrievals. By combining the MCRS with other techniques that focus primarily on optically thin cirrus over low water clouds, it will be possible to more fully assess the IWP in all conditions over ocean except for precipitating systems. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. Sci Syst & Applicat Inc, Hampton, VA 23666 USA. Lanzhou Univ, Coll Atmospher Sci, Lanzhou 730000, Peoples R China. Univ Utah, Dept Meteorol, Salt Lake City, UT 84122 USA. RP Minnis, P (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. RI Minnis, Patrick/G-1902-2010 OI Minnis, Patrick/0000-0002-4733-6148 NR 29 TC 24 Z9 25 U1 0 U2 11 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAR 20 PY 2007 VL 112 IS D6 AR D06206 DI 10.1029/2006JD007626 PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 150AD UT WOS:000245187100001 ER PT J AU Smart, MC Ratnakumar, BV Behar, A Whitcanack, LD Yu, JS Alamgir, M AF Smart, M. C. Ratnakumar, B. V. Behar, A. Whitcanack, L. D. Yu, J. -S. Alamgir, M. TI Gel polymer electrolyte lithium-ion cells with improved low temperature performance SO JOURNAL OF POWER SOURCES LA English DT Article; Proceedings Paper CT Joint Meeting of the International-Battery-Association/Hawaii Battery Conference (IBA-HBC 2006) CY JAN 09-12, 2006 CL Hilo, HI SP TIMCAL DE gel polymer Li-ion cells; low temperature Li-ion electrolytes ID BATTERIES AB For a number of NASA's future planetary and terrestrial applications, high energy density rechargeable lithium batteries that can operate at very low temperature are desired. In the pursuit of developing Li-ion batteries with improved low temperature performance, we have also focused on assessing the viability of using gel polymer systems, due to their desirable form factor and enhanced safety characteristics. In the present study we have evaluated three classes of promising liquid low-temperature electrolytes that have been impregnated into gel polymer electrolyte carbon-LiMn2O4-based Li-ion cells (manufactured by LG Chem. Inc.), consisting of: (a) binary EC + EMC mixtures with very low EC-content (10%), (b) quaternary carbonate mixtures with low EC-content (16-20%), and (c) ternary electrolytes with very low EC-content (10%) and high proportions of ester co-solvents (i.e., 80%). These electrolytes have been compared with a baseline formulation (i.e., 1.0 M LiPF6 in EC + DEC + DMC (1:1:1%, v/v/v), where EC, ethylene carbonate, DEC, diethyl carbonate, and DMC, dimethyl carbonate). We have performed a number of characterization tests on these cells, including: determining the rate capacity as a function of temperature (with preceding charge at room temperature and also at low temperature), the cycle life performance (both 100% DOD and 30% DOD low earth orbit cycling), the pulse capability, and the impedance characteristics at different temperatures. We have obtained excellent performance at low temperatures with ester-based electrolytes, including the demonstration of > 80% of the room temperature capacity at -60 degrees C using a C/20 discharge rate with cells containing 1.0 M LiPF6 in EC+EMC+MB (1:1:8%, v/v/v) (MB, methyl butyrate) and 1.0 M LiPF6 in EC+EMC+EB (1:1:8%, v/v/v) (EB, ethyl butyrate) electrolytes. In addition, cells containing the ester-based electrolytes were observed to support 5C pulses at -40 degrees C, while still maintaining a voltage > 2.5 V at 100 and 80% state-of-charge (SOC). (c) 2006 Elsevier B.V. All rights reserved. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. LG Chem Res Pk, Taejon, South Korea. Compact Power Inc, Troy, MI 48083 USA. RP Smart, MC (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM Marshall.C.Smart@jpl.nasa.gov NR 17 TC 17 Z9 27 U1 3 U2 34 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0378-7753 J9 J POWER SOURCES JI J. Power Sources PD MAR 20 PY 2007 VL 165 IS 2 BP 535 EP 543 DI 10.1016/j.jpowsour.2006.10.038 PG 9 WC Chemistry, Physical; Electrochemistry; Energy & Fuels; Materials Science, Multidisciplinary SC Chemistry; Electrochemistry; Energy & Fuels; Materials Science GA 152NQ UT WOS:000245369100006 ER PT J AU Myneni, RB Yang, WZ Nemani, RR Huete, AR Dickinson, RE Knyazikhin, Y Didan, K Fu, R Juarez, RIN Saatchi, SS Hashimoto, H Ichii, K Shabanov, NV Tan, B Ratana, P Privette, JL Morisette, JT Vermote, EF Roy, DP Wolfe, RE Friedl, MA Running, SW Votava, P El-Saleous, N Devadiga, S Su, Y Salomonson, VV AF Myneni, Ranga B. Yang, Wenze Nemani, Ramakrishna R. Huete, Alfredo R. Dickinson, Robert E. Knyazikhin, Yuri Didan, Kamel Fu, Rong Juarez, Robinson I. Negron Saatchi, Sasan S. Hashimoto, Hirofumi Ichii, Kazuhito Shabanov, Nikolay V. Tan, Bin Ratana, Piyachat Privette, Jeffrey L. Morisette, Jeffrey T. Vermote, Eric F. Roy, David P. Wolfe, Robert E. Friedl, Mark A. Running, Steven W. Votava, Petr El-Saleous, Nazmi Devadiga, Sadashiva Su, Yin Salomonson, Vincent V. TI Large seasonal swings in leaf area of Amazon rainforests SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article DE remote sensing; tropical forests phenology; vegetation climate interaction ID TROPICAL FOREST; PHENOLOGY; GROWTH; TREES; CONSEQUENCES; DROUGHT; WATER; CO2 AB Despite early speculation to the contrary, all tropical forests studied to date display seasonal variations in the presence of new leaves, flowers, and fruits. Past studies were focused on the timing of phenological events and their cues but not on the accompanying changes in leaf area that regulate vegetation-atmosphere exchanges of energy, momentum, and mass. Here we report, from analysis of 5 years of recent satellite data, seasonal swings in green leaf area of approximate to 25% in a majority of the Amazon rainforests. This seasonal cycle is timed to the seasonality of solar radiation in a manner that is suggestive of anticipatory and opportunistic patterns of net leaf flushing during the early to mid part of the light-rich dry season and net leaf abscission during the cloudy wet season. These seasonal swings in leaf area may be critical to initiation of the transition from dry to wet season, seasonal carbon balance between photosynthetic gains and respiratory losses, and litterfall nutrient cycling in moist tropical forests. C1 Boston Univ, Dept Geog & Environm, Boston, MA 02215 USA. NASA, Ames Res Ctr, Ecosyst Sci & Technol Branch, Moffett Field, CA 94035 USA. Univ Arizona, Dept Soil Water & Environm Sci, Tucson, AZ 85721 USA. Georgia Inst Technol, Sch Earth & Atmospher Sci, Atlanta, GA 30332 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Calif State Univ Monterey Bay, Moffett Field, CA 94035 USA. NASA, Ames Res Ctr, Ecosyst Sci & Technol Branch, Moffett Field, CA 94035 USA. San Jose State Univ, Moffett Field, CA 94035 USA. NASA, Ames Res Ctr, Ecosyst Sci & Technol Branch, Moffett Field, CA 94035 USA. NASA, Goddard Space Flight Ctr, Biospher Sci Branch, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Terr Informat Syst Branch, Greenbelt, MD 20771 USA. Univ Maryland, Dept Geog, College Pk, MD 20742 USA. S Dakota State Univ, Geog Informat Sci Ctr Excellence, Brookings, SD 57007 USA. NASA, Goddard Space Flight Ctr, Raytheon Technol Serv Corp, Greenbelt, MD 20771 USA. Univ Montana, Sch Forestry, Missoula, MT 59812 USA. NASA, Goddard Space Flight Ctr, Sci Syst & Applicat Inc, Greenbelt, MD 20771 USA. Univ Utah, Dept Geog & Meteorol, Salt Lake City, UT 84112 USA. RP Dickinson, RE (reprint author), Boston Univ, Dept Geog & Environm, 675 Commonwealth Ave, Boston, MA 02215 USA. EM robted@eas.gatech.edu RI Mitchard, Edward/C-6346-2009; Ichii, Kazuhito/D-2392-2010; Privette, Jeffrey/G-7807-2011; Yang, Wenze/B-8356-2012; Wolfe, Robert/E-1485-2012; Tan, Bin/G-1331-2012; Vermote, Eric/K-3733-2012; Fu, Rong/B-4922-2011; Myneni, Ranga/F-5129-2012; Huete, Alfredo/C-1294-2008; OI Ichii, Kazuhito/0000-0002-8696-8084; Privette, Jeffrey/0000-0001-8267-9894; Yang, Wenze/0000-0001-8514-2742; Wolfe, Robert/0000-0002-0915-1855; Huete, Alfredo/0000-0003-2809-2376; Ratana, Piyachat/0000-0002-1853-2860 NR 29 TC 193 Z9 200 U1 2 U2 58 PU NATL ACAD SCIENCES PI WASHINGTON PA 2101 CONSTITUTION AVE NW, WASHINGTON, DC 20418 USA SN 0027-8424 J9 P NATL ACAD SCI USA JI Proc. Natl. Acad. Sci. U. S. A. PD MAR 20 PY 2007 VL 104 IS 12 BP 4820 EP 4823 DI 10.1073/pnas.0611338104 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 150YY UT WOS:000245256700012 PM 17360360 ER PT J AU Mishchenko, MI Liu, L Mackowski, DW Cairns, B Videen, G AF Mishchenko, Michael I. Liu, Li Mackowski, Daniel W. Cairns, Brian Videen, Gorden TI Multiple scattering by random particulate media: exact 3D results SO OPTICS EXPRESS LA English DT Article ID DISCRETE RANDOM MEDIUM; WEAK-LOCALIZATION; COHERENT BACKSCATTERING; ELECTROMAGNETIC-WAVES; AGGLOMERATE PARTICLES; CLASSICAL DIFFUSION; SIZE PARAMETERS; T-MATRIX; LIGHT; POLARIZATION AB We use the numerically exact superposition T-matrix method to perform extensive computations of electromagnetic scattering by a 3D volume filled with randomly distributed wavelength-sized particles. These computations are used to simulate and analyze the effect of randomness of particle positions as well as the onset and evolution of various multiple-scattering effects with increasing number of particles in a statistically homogeneous volume of discrete random medium. Our exact results illustrate and substantiate the methodology underlying the microphysical theories of radiative transfer and coherent backscattering. Furthermore, we show that even in densely packed media, the light multiply scattered along strings of widely separated particles still provides a significant contribution to the total scattered signal and thereby makes quite pronounced the classical radiative transfer and coherent backscattering effects. (c) 2007 Optical Society of America. C1 NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Auburn Univ, Dept Mech Engn, Auburn, AL 36849 USA. USA, AMSRD, ARL, CI,EM,Res Lab, Adelphi, MD 20783 USA. RP Mishchenko, MI (reprint author), NASA, Goddard Inst Space Studies, 2880 Broadway, New York, NY 10025 USA. EM mmishchenko@giss.nasa.gov RI Mackowski, Daniel/K-1917-2013; Mishchenko, Michael/D-4426-2012; OI Cairns, Brian/0000-0002-1980-1022 NR 47 TC 84 Z9 84 U1 2 U2 12 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1094-4087 J9 OPT EXPRESS JI Opt. Express PD MAR 19 PY 2007 VL 15 IS 6 BP 2822 EP 2836 DI 10.1364/OE.15.002822 PG 15 WC Optics SC Optics GA 148LN UT WOS:000245076200008 PM 19532520 ER PT J AU Grudinin, IS Matsko, AB Maleki, L AF Grudinin, Ivan S. Matsko, Andrey B. Maleki, Lute TI On the fundamental limits of Q factor of crystalline dielectric resonators SO OPTICS EXPRESS LA English DT Article ID CALCIUM-FLUORIDE; SCATTERING; TEMPERATURE; CAF2 AB The temperature dependence of the processes which fundamentally limit optical quality factor of ideal crystalline whispering gallery mode resonators is investigated. The example of CaF2 is used to show that spontaneous Raman scattering is the main limitation of the quality factor at low temperatures. Stimulated Raman scattering is also shown to be important at any temperature. We experimentally demonstrate nonlinear absorption due to stimulated Raman scattering in a real cavity at room temperature and theoretically derive Raman gain of CaF2. We conclude that optical storage times in excess of one second could be achieved in millimeter sized cavities. (c) 2007 Optical Society of America. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Grudinin, IS (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM grudinin@caltech.edu RI Matsko, Andrey/A-1272-2007 NR 19 TC 19 Z9 20 U1 2 U2 11 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1094-4087 J9 OPT EXPRESS JI Opt. Express PD MAR 19 PY 2007 VL 15 IS 6 BP 3390 EP 3395 DI 10.1364/OE.15.003390 PG 6 WC Optics SC Optics GA 148LN UT WOS:000245076200068 PM 19532580 ER PT J AU Fuller, KA Smith, DD AF Fuller, Kirk A. Smith, David D. TI Cascaded photoenhancement from coupled nanoparticle and microcavity resonance effects SO OPTICS EXPRESS LA English DT Article ID ENHANCED RAMAN-SCATTERING; ENERGY-TRANSFER; ISLAND FILMS; SHIFT; MICROSPHERES; CAVITIES AB Calculations, based on modal analysis of scattering and absorption by compound spheres indicate that the absorption cross sections of metal nanoparticles immobilized onto dielectric microspheres can be greatly enhanced by cavity resonances in the microspheres without significant degradation of the resonators. Gain factors for optical processes associated with the nanoparticles of 103-104 are predicted for realistic experimental conditions using homogenous microspheres. This mechanism for cascaded photoenhancement thus has the potential of dramatically increasing the sensitivities of vibrational and photoluminescent spectroscopies. (c) 2007 Optical Society of America. C1 Univ Alabama, Natl Space Sci & Technol Ctr, Huntsville, AL 35899 USA. NASA, Marshall Space Flight Ctr, Space Transportat Directorate EV43, Huntsville, AL 35726 USA. RP Fuller, KA (reprint author), Univ Alabama, Natl Space Sci & Technol Ctr, Huntsville, AL 35899 USA. EM fuller@nsstc.uah.edu; david.d.smith@msfc.nasa.gov NR 28 TC 10 Z9 10 U1 1 U2 8 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1094-4087 J9 OPT EXPRESS JI Opt. Express PD MAR 19 PY 2007 VL 15 IS 6 BP 3575 EP 3580 DI 10.1364/OE.15.003575 PG 6 WC Optics SC Optics GA 148LN UT WOS:000245076200089 PM 19532601 ER PT J AU Marchand, RT Ackerman, TP Moroney, C AF Marchand, Roger T. Ackerman, Thomas P. Moroney, Catherine TI An assessment of Multiangle Imaging Spectroradiometer (MISR) stereo-derived cloud top heights and cloud top winds using ground-based radar, lidar, and microwave radiometers SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID RETRIEVAL; PROFILER; PERFORMANCE; MOTION; FIRE; SIZE; RASS AB [1] In this article stereoscopically derived cloud top heights and cloud winds estimated from the Multiangle Imaging Spectroradiometer (MISR) are assessed. MISR is one of five instruments on board the NASA Terra satellite. The cloud top height assessment is based on a comparison of more than 4 years of MISR retrievals with that derived from ground-based radar and lidar systems operated by the U. S. Department of Energy Atmospheric Radiation Measurement program. The assessment includes a comparison of the MISR cloud top heights and ground-based data sets as a function of cloud optical depth and a simple cloud classification. Overall, we find that the MISR retrieval is working well with little bias for most cloud types, when the cloud is sufficiently optically thick to be detected. The detection limit is found to be around optical depth 0.3 to 0.5, except over snow and ice surfaces where it is larger. The standard deviation across all clouds is less than about 1000 m for the MISR best winds retrievals at all ARM sites, and the standard deviation for the MISR without winds retrieval varied between about 1000 to 1300 m, depending on the site. The performance for various cloud types is explored. C1 Pacific NW Natl Lab, Richland, WA 99352 USA. NASA, Jet Prop Lab, Pasadena, CA 91109 USA. RP Marchand, RT (reprint author), Pacific NW Natl Lab, POB 999, Richland, WA 99352 USA. EM roj@pnl.gov NR 27 TC 34 Z9 35 U1 1 U2 10 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAR 17 PY 2007 VL 112 IS D6 AR D06204 DI 10.1029/2006JD007091 PG 20 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 147QN UT WOS:000245017600001 ER PT J AU Pritchard, ME Norabuena, EO Ji, C Boroschek, R Comte, D Simons, M Dixon, TH Rosen, PA AF Pritchard, M. E. Norabuena, E. O. Ji, C. Boroschek, R. Comte, D. Simons, M. Dixon, T. H. Rosen, P. A. TI Geodetic, teleseismic, and strong motion constraints on slip from recent southern Peru subduction zone earthquakes SO JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH LA English DT Article ID SYNTHETIC-APERTURE RADAR; 12 NOVEMBER 1996; RUPTURE PROCESS; M-W; COSEISMIC DEFORMATION; SURFACE DEFORMATION; GPS OBSERVATIONS; CENTRAL ANDES; NAZCA RIDGE; HECTOR MINE AB We use seismic and geodetic data both jointly and separately to constrain coseismic slip from the 12 November 1996 M-w 7.7 and 23 June 2001 M-w 8.5 southern Peru subduction zone earthquakes, as well as two large aftershocks following the 2001 earthquake on 26 June and 7 July 2001. We use all available data in our inversions: GPS, interferometric synthetic aperture radar ( InSAR) from the ERS-1, ERS-2, JERS, and RADARSAT-1 satellites, and seismic data from teleseismic and strong motion stations. Our two-dimensional slip models derived from only teleseismic body waves from South American subduction zone earthquakes with M-w > 7.5 do not reliably predict available geodetic data. In particular, we find significant differences in the distribution of slip for the 2001 earthquake from models that use only seismic ( teleseismic and two strong motion stations) or geodetic ( InSAR and GPS) data. The differences might be related to postseismic deformation or, more likely, the different sensitivities of the teleseismic and geodetic data to coseismic rupture properties. The earthquakes studied here follow the pattern of earthquake directivity along the coast of western South America, north of 5 degrees S, earthquakes rupture to the north; south of about 12 degrees S, directivity is southerly; and in between, earthquakes are bilateral. The predicted deformation at the Arequipa GPS station from the seismic-only slip model for the 7 July 2001 aftershock is not consistent with significant preseismic motion. C1 Cornell Univ, Dept Earth & Atmospher Sci, Ithaca, NY 14853 USA. Inst Geofis Peru, Dept Geodesia & Sismotecton, Lima 3, Peru. CALTECH, Div Geol & Planetary Sci, Seismol Lab, Pasadena, CA 91125 USA. Univ Chile, Dept Ingn Civil, Santiago, Chile. Univ Chile, Dept Geofis, Santiago, Chile. Univ Miami, Rosenstiel Sch Marine & Atmospher Sci, MGG, Miami, FL 33149 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Pritchard, ME (reprint author), Cornell Univ, Dept Earth & Atmospher Sci, Snee Hall, Ithaca, NY 14853 USA. EM mp337@cornell.edu RI Boroschek, Ruben/H-6195-2013; Norabuena, Edmundo/I-5486-2013; COMTE, DIANA/H-2593-2013; Pritchard, Matthew/L-5892-2015; OI Boroschek, Ruben/0000-0003-2253-2334; Pritchard, Matthew/0000-0003-3616-3373; Simons, Mark/0000-0003-1412-6395 NR 75 TC 40 Z9 40 U1 1 U2 8 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9313 EI 2169-9356 J9 J GEOPHYS RES-SOL EA JI J. Geophys. Res.-Solid Earth PD MAR 17 PY 2007 VL 112 IS B3 AR B03307 DI 10.1029/2006JB004294 PG 24 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 147SN UT WOS:000245022900001 ER PT J AU McComas, DJ Velli, M Lewis, WS Acton, LW Balat-Pichelin, M Bothmer, V Dirling, RB Feldman, WC Gloeckler, G Habbal, SR Hassler, DM Mann, I Matthaeus, WH McNutt, RL Mewaldt, RA Murphy, N Ofman, L Sittler, EC Smith, CW Zurbuchen, TH AF McComas, D. J. Velli, M. Lewis, W. S. Acton, L. W. Balat-Pichelin, M. Bothmer, V. Dirling, R. B., Jr. Feldman, W. C. Gloeckler, G. Habbal, S. R. Hassler, D. M. Mann, I. Matthaeus, W. H. McNutt, R. L., Jr. Mewaldt, R. A. Murphy, N. Ofman, L. Sittler, E. C., Jr. Smith, C. W. Zurbuchen, T. H. TI Understanding coronal heating and solar wind acceleration: Case for in situ near-Sun measurements SO REVIEWS OF GEOPHYSICS LA English DT Review ID ENERGETIC PARTICLE EVENTS; ROTATING RAREFACTION REGIONS; HELIOSPHERIC MAGNETIC-FIELD; EJECTION DRIVEN SHOCKS; MASS EJECTIONS; ALFVEN WAVES; POLAR PLUMES; MAGNETOHYDRODYNAMIC TURBULENCE; INTERPLANETARY MEDIUM; RESONANT ABSORPTION AB The solar wind has been measured directly from 0.3 AU outward, and the Sun's atmosphere has been imaged from the photosphere out through the corona. These observations have significantly advanced our understanding of the influence of the Sun's varying magnetic field on the structure and dynamics of the corona and the solar wind. However, how the corona is heated and accelerated to produce the solar wind remains a mystery. Answering these fundamental questions requires in situ observations near the Sun, from a few solar radii (R-S) out to similar to 20 R-S, where the internal, magnetic, and turbulent energy in the coronal plasma is channeled into the bulk energy of the supersonic solar wind. A mission to make such observations has long been a top priority of the solar and space physics community. The recent Solar Probe study has proven that such a mission is technically feasible and can be accomplished within reasonable resources. C1 SW Res Inst, Space Sci & Engn Div, San Antonio, TX 78228 USA. Univ Florence, Dipartimento Astron & Sci Spazio, I-50125 Florence, Italy. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Montana State Univ, Dept Phys, Bozeman, MT 59717 USA. CNRS, Proc Mat & Solar Energy, F-66125 Font Romeu, France. Univ Gottingen, Inst Astrophys, D-37077 Gottingen, Germany. Sci Applicat Int Corp, Fountain Valley, CA 92708 USA. Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Univ Maryland, Dept Phys, College Pk, MD 20742 USA. Univ Hawaii Manoa, Inst Astron, Honolulu, HI 96822 USA. SW Res Inst, Space Studies Dept, Boulder, CO 80302 USA. Kobe Univ, Dept Earth & Planetary Sci, Nada Ku, Kobe, Hyogo 6578501, Japan. Univ Delaware, Bartol Res Inst, Newark, DE 19716 USA. Johns Hopkins Univ, Appl Phys Lab, Laurel, MD 20723 USA. CALTECH, Space Radiat Lab, Pasadena, CA 91125 USA. Catholic Univ Amer, Dept Phys, Washington, DC 20064 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ New Hampshire, Dept Earth Oceans & Space, Durham, NH 03824 USA. Univ Michigan, Dept Atmospher Ocean & Space Sci, Ann Arbor, MI 48109 USA. RP McComas, DJ (reprint author), SW Res Inst, Space Sci & Engn Div, PO Drawer 28510, San Antonio, TX 78228 USA. EM dmccomas@swri.edu RI McNutt, Ralph/E-8006-2010 OI McNutt, Ralph/0000-0002-4722-9166 NR 151 TC 33 Z9 33 U1 0 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 8755-1209 EI 1944-9208 J9 REV GEOPHYS JI Rev. Geophys. PD MAR 17 PY 2007 VL 45 IS 1 AR RG1004 DI 10.1029/2006RG000195 PG 26 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 147TU UT WOS:000245026200001 ER PT J AU Gonzalez, WD Echer, E Clua-Gonzalez, AL Tsurutani, BT AF Gonzalez, W. D. Echer, E. Clua-Gonzalez, A. L. Tsurutani, B. T. TI Interplanetary origin of intense geomagnetic storms (Dst <-100 nT) during solar cycle 23 SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID CORONAL MASS EJECTIONS; SOLAR-WIND; MAGNETIC STORMS; GEOEFFECTIVENESS; DISTURBANCES; PARAMETERS; MAXIMUM; CLOUDS AB We study the interplanetary causes of intense geomagnetic storms (Dst < -100 nT) that occurred during solar cycle 23 (1997-2005). It was found that the most common interplanetary structures leading to the development of an intense storm were: magnetic clouds, sheath fields, sheath fields followed by a magnetic cloud and corotating interaction regions leading high speed streams. However, the relative importance of each of those driving structures was found to vary with the solar cycle phase. We divide the cycle in three phases (rising, maximum and declining) and explain the differences. We also discuss about the geoeffectiveness of each of the four main interplanetary driving structures. C1 INPE, BR-12245970 Sao Jose Dos Campos, Brazil. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Gonzalez, WD (reprint author), INPE, CP 515, BR-12245970 Sao Jose Dos Campos, Brazil. EM gonzalez@dge.inpe.br NR 24 TC 48 Z9 51 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD MAR 16 PY 2007 VL 34 IS 6 AR L06101 DI 10.1029/2006GL028879 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 147QB UT WOS:000245016400002 ER PT J AU Varnai, T Marshak, A AF Varnai, Tamas Marshak, Alexander TI View angle dependence of cloud optical thicknesses retrieved by Moderate Resolution Imaging Spectroradiometer (MODIS) SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID NEURAL-NETWORK RETRIEVAL; SOLAR ZENITH ANGLE; FRACTAL CLOUDS; RADIANCE; BIASES; INHOMOGENEITY; STRATOCUMULUS; REFLECTANCES; FEASIBILITY; VARIABILITY AB This study examines whether cloud inhomogeneity influences the view angle dependence of MODIS cloud optical thickness retrieval results. The degree of cloud inhomogeneity is characterized through the local gradient in 11 mm brightness temperature. The analysis of liquid phase clouds in a 1 year long global data set of Collection 4 MODIS data reveals that while optical thickness retrievals give remarkably consistent results for all view directions if clouds are homogeneous, they give much higher tau-values for oblique views than for overhead views if clouds are inhomogeneous and the Sun is fairly oblique. The mean optical thickness retrieved for the most inhomogeneous third of cloudy pixels is more than 40% higher for oblique views than for overhead views if the solar zenith angle exceeds 60 degrees. After considering a variety of possible scenarios, the paper concludes that the most likely reason for the increase lies in three-dimensional radiative interactions that are not considered in current, one-dimensional retrieval algorithms. Namely, the radiative effect of cloud sides viewed at oblique angles seems to contribute most to the enhanced optical thickness values. The results presented here will help understand and estimate cloud retrieval uncertainties related to cloud inhomogeneity and may eventually help correct for the observed view angle-dependent biases. C1 Univ Maryland Baltimore Cty, Joint Ctr Earth Syst Technol, Baltimore, MD 21228 USA. NASA, Goddard Space Flight Ctr, Climate & Radiat Branch, Greenbelt, MD 20771 USA. RP Varnai, T (reprint author), Univ Maryland Baltimore Cty, Joint Ctr Earth Syst Technol, Baltimore, MD 21228 USA. EM varnai@climate.gsfc.nasa.gov RI Marshak, Alexander/D-5671-2012 NR 35 TC 26 Z9 26 U1 1 U2 6 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAR 16 PY 2007 VL 112 IS D6 AR D06203 DI 10.1029/2005JD006912 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 147QM UT WOS:000245017500002 ER PT J AU Mishchenko, MI Geogdzhayev, IV Rossow, WB Cairns, B Carlson, BE Lacis, AA Liu, L Travis, LD AF Mishchenko, Michael I. Geogdzhayev, Igor V. Rossow, William B. Cairns, Brian Carlson, Barbara E. Lacis, Andrew A. Liu, Li Travis, Larry D. TI Long-term satellite record reveals likely recent aerosol trend SO SCIENCE LA English DT Article ID SOLAR-RADIATION; SURFACE; CLIMATE; SPACE C1 NASA, Goddard Inst Space Studies, New York, NY 10025 USA. RP Mishchenko, MI (reprint author), NASA, Goddard Inst Space Studies, 2880 Broadway, New York, NY 10025 USA. EM mmishchenko@giss.nasa.gov RI Lacis, Andrew/D-4658-2012; Carlson, Barbara/D-8319-2012; Rossow, William/F-3138-2015; Mishchenko, Michael/D-4426-2012; OI Cairns, Brian/0000-0002-1980-1022 NR 10 TC 131 Z9 136 U1 4 U2 20 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 EI 1095-9203 J9 SCIENCE JI Science PD MAR 16 PY 2007 VL 315 IS 5818 BP 1543 EP 1543 DI 10.1126/science.1136709 PG 1 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 146LB UT WOS:000244934800042 PM 17363666 ER PT J AU Fricker, HA Scambos, T Bindschadler, R Padman, L AF Fricker, Helen Amanda Scambos, Ted Bindschadler, Robert Padman, Laurie TI An active subglacial water system in West Antarctica mapped from space SO SCIENCE LA English DT Article ID ICE STREAM-B; BENEATH; SHEETS; LAKES; JOKULHLAUP; DISCHARGE; MECHANISM; IMAGERY; RADAR AB Satellite laser altimeter elevation profiles from 2003 to 2006 collected over the lower parts of Whillans and Mercer ice streams, West Antarctica, reveal 14 regions of temporally varying elevation, which we interpret as the surface expression of subglacial water movement. Vertical motion and spatial extent of two of the largest regions are confirmed by satellite image differencing. A major, previously unknown subglacial lake near the grounding line of Whillans Ice Stream is observed to drain 2.0 cubic kilometers of water into the ocean over similar to 3 years, while elsewhere a similar volume of water is being stored subglacially. These observations reveal a widespread, dynamic subglacial water system that may exert an important control on ice flow and mass balance. C1 Univ Calif San Diego, Scripps Inst Oceanog, Inst Geophys & Planetary Phys, La Jolla, CA 92093 USA. Univ Colorado, Natl Snow & Ice Data Ctr, Boulder, CO 80302 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Earth & Space Res, Corvallis, OR 97333 USA. RP Fricker, HA (reprint author), Univ Calif San Diego, Scripps Inst Oceanog, Inst Geophys & Planetary Phys, La Jolla, CA 92093 USA. EM hafricker@ucsd.edu RI Scambos, Ted/B-1856-2009 NR 33 TC 232 Z9 239 U1 3 U2 48 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 EI 1095-9203 J9 SCIENCE JI Science PD MAR 16 PY 2007 VL 315 IS 5818 BP 1544 EP 1548 DI 10.1126/science.1136897 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 146LB UT WOS:000244934800043 PM 17303716 ER PT J AU Hurowitz, JA Tosca, NJ McLennan, SM Schoonen, MAA AF Hurowitz, Joel A. Tosca, Nicholas J. McLennan, Scott M. Schoonen, Martin A. A. TI Production of hydrogen peroxide in Martian and lunar soils SO EARTH AND PLANETARY SCIENCE LETTERS LA English DT Article DE Mars; Moon; oxidant; soil; silicosis; reactivity ID OXIDANT ENHANCEMENT; HYDROXYL RADICALS; SILICA SURFACE; DUST DEVILS; GENERATION; REACTIVITY; MARS; LIFE; SUPEROXIDE; OXIDES AB Freshly ground basaltic minerals produce sufficient quantities of hydrogen peroxide (H2O2) when immersed in solution to explain the oxidizing characteristics of Martian soil samples collected by the Viking landers. H2O2 production occurs as a result of reactions between water and defects at the surface of mechanically pulverized minerals, analogous to carcinogenic quartz dusts. Our results also indicate that dehydroxylation of mineral surfaces results in increased H2O2 production, a highly relevant finding for dusts on the airless surface of the Moon. Reactive, pulverized minerals are important on planetary bodies where impact processes have generated fine-grained basaltic dusts, and may pose a significant health risk to astronauts visiting planetary surfaces where impacts have generated such materials. (c) 2006 Elsevier B.V. All rights reserved. C1 SUNY Stony Brook, Dept Geosci, Stony Brook, NY 11794 USA. RP Hurowitz, JA (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,M-S 183-501, Pasadena, CA 91109 USA. EM joel.a.hurowitz@jpl.nasa.gov RI Hurowitz, Joel/A-8862-2008; Schoonen, martin/E-7703-2011 OI Schoonen, martin/0000-0002-7133-1160 NR 44 TC 39 Z9 40 U1 2 U2 23 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0012-821X J9 EARTH PLANET SC LETT JI Earth Planet. Sci. Lett. PD MAR 15 PY 2007 VL 255 IS 1-2 BP 41 EP 52 DI 10.1016/j.epsl.2006.12.004 PG 12 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 149JQ UT WOS:000245143600005 ER PT J AU Koch, D Bond, TC Streets, D Unger, N AF Koch, Dorothy Bond, Tami C. Streets, David Unger, Nadine TI Linking future aerosol radiative forcing to shifts in source activities SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID BLACK CARBON; EMISSIONS; SIMULATIONS; TRANSPORT; SULFATE; MODELE; RANGE AB We model future direct radiative forcings of the major anthropogenic aerosol species, sulfate, black and organic carbon, within industrial, power, transport, and residential sectors and biomass burning. A sectoral perspective helps to inform mitigation directions. More accurate projections are facilitated by recent carbonaceous aerosol emission estimates that incorporate projected technology changes, now available for the Intergovernmental Panel on Climate Change scenarios A1B and B1, for 2030 and 2050. Net present-day model anthropogenic forcing is -0.11W m(-2). By 2050 this doubles ( A1B) or drops by 30% ( B1), depending mostly on sulfate changes in the industry and power sectors. Present-day (nonbiomass burning) BC forcing comes mostly from residential sources (+0.09 W m(-2)), however this is projected to decrease by more than a factor of 10 by 2050. Future BC forcing is projected to come mostly from transport, changing from +0.06 W m(-2) in 2000 to +0.04 (B1) or +0.07 W m(-2) (A1B) by 2050. C1 Columbia Univ, NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Univ Illinois, Urbana, IL 61801 USA. Argonne Natl Lab, Argonne, IL 60439 USA. Univ Vermont, Rubenstein Sch Environm & Nat Resources, Burlington, VT 05405 USA. RP Koch, D (reprint author), Columbia Univ, NASA, Goddard Inst Space Studies, 2880 Broadway, New York, NY 10025 USA. EM dkoch@giss.nasa.gov RI Bond, Tami/A-1317-2013; Unger, Nadine/M-9360-2015 OI Streets, David/0000-0002-0223-1350; Bond, Tami/0000-0001-5968-8928; NR 19 TC 23 Z9 24 U1 0 U2 6 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD MAR 15 PY 2007 VL 34 IS 5 AR L05821 DI 10.1029/2006GL028360 PG 5 WC Geosciences, Multidisciplinary SC Geology GA 147PY UT WOS:000245016100001 ER PT J AU Mikellides, IG Katz, I Goebel, DM Jameson, KK AF Mikellides, Ioannis G. Katz, Ira Goebel, Dan M. Jameson, Kristina K. TI Evidence of nonclassical plasma transport in hollow cathodes for electric propulsion SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID BUNEMAN INSTABILITY; RESISTIVITY AB Measurements, simplified analyses, and two-dimensional numerical simulations with a fluid plasma model show that classical resistivity cannot account for the elevated electron temperatures and steep plasma potential gradients measured in a 25-27.5 A electric propulsion hollow cathode. The cathode consisted of a 1.5 cm hollow tube with an similar to 0.28 cm diameter orifice and was operated with 5.5 SCCM (SCCM denotes cubic centimeter per minute at STP) of xenon flow using two different anode geometries: a segmented cone and a circular flat plate. The numerical simulations show that classical resistivity yields as much as four times colder electron temperatures compared to the measured values in the orifice and near-plume regions of the cathode. Classical transport and Ohm's law also predict exceedingly high electron-ion relative drift speeds compared to the electron thermal speed (> 4). It is found that the addition of anomalous resistivity based on existing growth rate formulas for electron-ion streaming instabilities improves qualitatively the comparison between the numerical results and the time-averaged measurements. Simplified analyses that have been based largely on the axial measurements support the conclusion that additional resistivity is required in Ohm's law to explain the measurements. The combined results from the two-dimensional simulations and the analyses bound the range of enhanced resistivity to be 3-100 times the classical value. (c) 2007 American Institute of Physics. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Mikellides, IG (reprint author), CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. EM ioannis.g.mikellides@jpl.nasa.gov NR 22 TC 9 Z9 9 U1 2 U2 14 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD MAR 15 PY 2007 VL 101 IS 6 AR 063301 DI 10.1063/1.2710763 PG 11 WC Physics, Applied SC Physics GA 151VA UT WOS:000245317700013 ER PT J AU Pugel, DE Vispute, RD Hullavarad, SS Venkatesan, T Varughese, B AF Pugel, D. Elizabeth Vispute, R. D. Hullavarad, S. S. Venkatesan, T. Varughese, B. TI Oxygen-dependent phosphorus networking in ZnO thin films grown by low temperature rf sputtering SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID DEFECTS; GLASS; XPS AB Radio frequency (rf) sputtered films of 10 at. % P2O5-doped zinc oxide (ZnO) were deposited at temperatures (T-d) below the sublimation point of P2O5 (T-d < 350 degrees C) and at a range of oxygen pressures p(O-2). Ultraviolet-visible optical transmission measurements, x-ray photoelectron spectroscopy (XPS), and x-ray diffraction were used to examine the effects of p(O-2) during deposition on the band gap and on the bonding behavior of phosphorus. At both deposition temperatures studied (room temperature with unintentional heating and 125 degrees C), an increase in phosphorus concentration with increasing p(O-2) was observed. However, the dependence of the band gap behavior on p(O-2) was observed to be dramatically different for the two deposition temperatures: room-temperature-deposited films show a redshift while films deposited at 125 degrees C show a blueshift. Analysis of the oxygen 1s XPS peak shows a progressive formation of nonbridging (Zn-O-P) bond networks for room temperature films, whereas films grown at 125 degrees C show increased (P-O-P) bond networks with increasing p(O-2). This indicates that a small degree of thermal activation considerably modifies the bonding behavior of phosphorus in ZnO. Implications of these results for the use of phosphorus as a p-type dopant for ZnO are discussed. (c) 2007 American Institute of Physics. C1 Univ Maryland, Dept Phys, College Pk, MD 20742 USA. Univ Maryland, Dept Mat Sci & Engn, College Pk, MD 20742 USA. RP Pugel, DE (reprint author), NASA, Goddard Space Flight Ctr, Detector Syst Branch, Greenbelt, MD 20771 USA. EM diane.e.pugel@nasa.gov RI Venkatesan, Thirumalai/E-1667-2013 NR 12 TC 7 Z9 7 U1 0 U2 4 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD MAR 15 PY 2007 VL 101 IS 6 AR 063538 DI 10.1063/1.2715551 PG 5 WC Physics, Applied SC Physics GA 151VA UT WOS:000245317700059 ER PT J AU Su, N Fay, P Sinharoy, S Forbes, D Scheiman, D AF Su, Ning Fay, Patrick Sinharoy, Samar Forbes, David Scheiman, David TI Characterization and modeling of InGaAs/InAsP thermophotovoltaic converters under high illumination intensities SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID ENERGY-CONVERSION; SPECTRAL CONTROL; RECOMBINATION; DEVICES; EFFICIENCY AB Thermophotovoltaic converters based on In0.69Ga0.31As/InAs0.34P0.66 have been fabricated, characterized experimentally, and modeled. Good device performance has been achieved with an open-circuit voltage of 1.46 V, short-circuit current density of 1.06 A/cm(2), and a fill factor of 71.3% for a four-junction cell under an optical power density of 3.4 W/cm(2). Key material parameters have been extracted from measured device characteristics, providing a detailed quantitative understanding of the dependence of device performance on the electro-optical properties of the InGaAs/InAsP material system. Extracted minority carrier lifetimes of 106 ns in the p-type base and 0.3 ns in the n-type emitter regions were obtained, limited by radiative and Auger recombination, respectively. The recombination velocity for the InGaAs/InAsP interface is found to be below 2000 cm/s. The parameter analysis provides guidance for the design of a high-efficiency monolithically integrated module for use under high illumination intensities. C1 Univ Notre Dame, Dept Elect Engn, Notre Dame, IN 46556 USA. Essential Res Inc, Cleveland, OH 44142 USA. NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Su, N (reprint author), Univ Notre Dame, Dept Elect Engn, Notre Dame, IN 46556 USA. EM pfay@nd.edu NR 24 TC 7 Z9 8 U1 0 U2 1 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0021-8979 EI 1089-7550 J9 J APPL PHYS JI J. Appl. Phys. PD MAR 15 PY 2007 VL 101 IS 6 AR 064511 DI 10.1063/1.2713366 PG 6 WC Physics, Applied SC Physics GA 151VA UT WOS:000245317700154 ER PT J AU Kim, JW Choi, SH Lillehei, PT Chu, SH King, GC Watt, GD AF Kim, Jae-Woo Choi, Sang H. Lillehei, Peter T. Chu, Sang-Hyon King, Glen C. Watt, Gerald D. TI Electrochemically controlled reconstitution of immobilized ferritins for bioelectronic applications SO JOURNAL OF ELECTROANALYTICAL CHEMISTRY LA English DT Article DE ferritin; immobilization; reconstitution; QCM; electrocatalyst ID 2-IMINOTHIOLANE METHYL 4-MERCAPTOBUTYRIMIDATE; INDIUM OXIDE ELECTRODES; PROTEIN CAGE; BIOMIMETIC SYNTHESIS; CROSS-LINKING; IRON STORAGE; HORSE SPLEEN; APOFERRITIN; COBALT; MAGNETOFERRITIN AB Site-specific reconstituted nanoparticles were fabricated via electrochemically controlled biomineralization through the immobilization of biomolecules. The work reported herein includes the immobilization of ferritin with various surface modifications, the electrochemical biomineralization of ferritins with different inorganic cores, and the electrocatalytic reduction of oxygen on the reconstituted Pt-cored ferritins. Protein immobilization on the substrate is achieved by anchoring ferritins with dithiobis-N-succinimidyl propionate (DTSP). A reconstitution process of site-specific electrochemical biomineralization with a protein cage loads ferritins with different core materials. The ferritin acts as a nano-scale template, a biocompatible cage, and a separator between the nanoparticles. This first demonstration of electrochemically controlled site-specific reconstitution of biomolecules provides a new tool for biomineralization and opens the way to produce the bio-templated nanoparticles by electrochemical control. The nanosized platinum-cored ferritins on gold displayed good catalytic activity for the electrochemical reduction of oxygen, which is applicable to biofuel cell applications. This results in a smaller catalyst loading on the electrodes for fuel cells or other bioelectronic devices. (c) 2006 Elsevier B.V. All rights reserved. C1 Natl Inst Aerosp, Hampton, VA 23666 USA. NASA, Langley Res Ctr, Adv Mat & Proc Branch, Hampton, VA 23681 USA. Brigham Young Univ, Dept Chem & Biochem, Provo, UT 84602 USA. RP Kim, JW (reprint author), Natl Inst Aerosp, Hampton, VA 23666 USA. EM fn.j.kim@larc.nasa.gov RI Kim, Jae-Woo/A-8314-2008; Lillehei, Peter/C-9196-2009 OI Lillehei, Peter/0000-0001-8183-9980 NR 40 TC 23 Z9 23 U1 1 U2 18 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0022-0728 J9 J ELECTROANAL CHEM JI J. Electroanal. Chem. PD MAR 15 PY 2007 VL 601 IS 1-2 BP 8 EP 16 DI 10.1016/j.jelechem.2006.10.018 PG 9 WC Chemistry, Analytical; Electrochemistry SC Chemistry; Electrochemistry GA 152UA UT WOS:000245386200002 ER PT J AU Opila, EJ Myers, DL Jacobson, NS Nielsen, IMB Johnson, DF Olminsky, JK Allendorf, MD AF Opila, Elizabeth J. Myers, Dwight L. Jacobson, Nathan S. Nielsen, Ida M. B. Johnson, Dereck F. Olminsky, Jami K. Allendorf, Mark D. TI Theoretical and experimental investigation of the thermochemistry of CrO2(OH)(2)(g) SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID GAUSSIAN-BASIS SETS; MOLECULAR CALCULATIONS; PROJECTION OPERATORS; CHROMIUM-OXIDE; WATER-VAPOR; ROW ATOMS; THERMODYNAMICS; CR2O3; VOLATILIZATION; CRO3 AB In this paper, we report the results of equilibrium pressure measurements designed to identify the volatile species in the Cr-O-H system and to resolve some of the discrepancies in existing experimental data. In addition, ab initio calculations were performed to lend confidence to a theoretical approach for predicting the thermochemistry of chromium-containing compounds. Equilibrium pressure data for CrO2(OH)(2) were measured by the transpiration technique for the reaction 0.5Cr(2)O(3)(s) + 0.75O(2)(g) + H2O(g) = CrO2(OH)(2)(g) over a temperature range of 573 to 1173 K at 1 bar total pressure. Inductively coupled plasma atomic emission spectroscopy (ICP-AES) was used to analyze the condensate in order to quantify the concentration of Cr-containing volatile species. The resulting experimentally measured thermodynamic functions are compared to those computed using B3LYP density functional theory and the coupled-cluster singles and doubles method with a perturbative correction for connected triple substitutions [CCSD(T)]. C1 NASA, Glenn Res Ctr, QSS Grp Inc, Cleveland, OH 44135 USA. E Cent Univ, Ada, OK 74820 USA. Sandia Natl Labs, Livermore, CA 94551 USA. RP Opila, EJ (reprint author), NASA, Glenn Res Ctr, QSS Grp Inc, Cleveland, OH 44135 USA. EM opila@nasa.gov RI Jacobson, Nathan/A-9411-2009 NR 43 TC 88 Z9 94 U1 3 U2 37 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD MAR 15 PY 2007 VL 111 IS 10 BP 1971 EP 1980 DI 10.1021/jp0647380 PG 10 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 143PM UT WOS:000244735000028 PM 17309237 ER PT J AU Hinkle, CE McCoy, AB Huang, XC Bowman, JM AF Hinkle, Charlotte E. McCoy, Anne B. Huang, Xinchuan Bowman, Joel M. TI Comment on "Nature of the chemical bond in protonated methane" SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID INFRARED-SPECTRUM; BARE CH5+; QUANTUM C1 Ohio State Univ, Dept Chem, Columbus, OH 43210 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Emory Univ, Dept Chem, Atlanta, GA 30322 USA. Emory Univ, Cherry L Emerson Ctr Sci Computat, Atlanta, GA 30322 USA. RP McCoy, AB (reprint author), Ohio State Univ, Dept Chem, Mail Stop 245-6, Columbus, OH 43210 USA. EM mccoy@chemistry.ohio-state.edu; jmbowma@emory.edu RI HUANG, XINCHUAN/A-3266-2013 NR 13 TC 5 Z9 5 U1 0 U2 6 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD MAR 15 PY 2007 VL 111 IS 10 BP 2033 EP 2034 DI 10.1021/jp067486b PG 2 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 143PM UT WOS:000244735000036 PM 17311368 ER PT J AU Ray, AK Dwarakadasa, ES Das, DK Ranganath, VR Goswami, B Sahu, JK Whittenberger, JD AF Ray, A. K. Dwarakadasa, E. S. Das, D. K. Ranganath, V. R. Goswami, B. Sahu, J. K. Whittenberger, J. D. TI Fatigue behavior of a thermal barrier coated superalloy at 800 degrees C SO MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING LA English DT Article DE thermal barrier coating (TBC); fatigue; superalloy; bond coat; substrate; endurance; stress; crack growth ID MECHANICAL-PROPERTIES; COATINGS; ALLOYS AB Fatigue testing of thermal barrier coated (TBC), bond coated only and bare Superni C263 superalloy was conducted at 800 degrees C in air. Results reveal that the endurance limits for the TBC and bond coated substrate was substantially higher than that of the base alloy, while the opposite was found for high stress, low cyclic life times. It appears that the increase in endurance limit for the TBC and bond coated superalloy is due to load shifting to the bond coat, and the premature failure for these two materials is possibly due to high stress crack imitation/growth in the TBC/bond coat layers. (c) 2006 Elsevier B.V. All rights reserved. C1 CSIR, Natl Met Lab, Jamshedpur 831007, Bihar, India. Indian Inst Sci, Bangalore 560012, Karnataka, India. Def Met Res Lab, Hyderabad 500058, Andhra Pradesh, India. CSIC, Natl Aerosp Lab, Bangalore 560017, Karnataka, India. RVS Coll Engn & Technol, Jamshedpur 831012, Bihar, India. NASA, Lewis Res Ctr, Cleveland, OH 44135 USA. RP Ray, AK (reprint author), CSIR, Natl Met Lab, Jamshedpur 831007, Bihar, India. EM asokroy@nmlindia.org RI Sahu, Anjani/E-7590-2015 NR 19 TC 19 Z9 19 U1 1 U2 4 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0921-5093 J9 MAT SCI ENG A-STRUCT JI Mater. Sci. Eng. A-Struct. Mater. Prop. Microstruct. Process. PD MAR 15 PY 2007 VL 448 IS 1-2 BP 294 EP 298 DI 10.1016/j.msea.2006.10.035 PG 5 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA 144JA UT WOS:000244791100041 ER PT J AU Bruegge, CJ Diner, DJ Kahn, RA Chrien, N Helmlinger, MC Gaitley, BJ Abdou, WA AF Bruegge, Carol J. Diner, David J. Kahn, Ralph A. Chrien, Nadine Helmlinger, Mark C. Gaitley, Barbara J. Abdou, Wedad A. TI The MISR radiometric calibration process SO REMOTE SENSING OF ENVIRONMENT LA English DT Article DE radiometric calibration; MISR ID ANGLE IMAGING SPECTRORADIOMETER; AEROSOL OPTICAL DEPTH; RETRIEVALS; SPECTRALON; SENSORS AB One important objective of the Multi-angle Imaging SpectroRadiometer (MISR) is retrieving global aerosol loading and microphysical properties. Accuracy depends on many factors, including the availability of a complete catalog of particle types with their associated size distributions, shapes, single-scattefing albedos, vertical profiles, and spectral radiative characteristics. Co-equal to this need is the availability of a well-designed, well-characterized instrument, with a calibration that is maintained post-launch. This allows accurate radiance and retrieval products to be made, adjusting for instrument changes. MISR performance has been intensively studied throughout the design, pre-flight, and post-launch mission phases. To establish the absolute radiometric scale, annual vicarious calibration (VC) exercises have been conducted. In addition, an on-board-calibrator (OBC) allows more frequent testing of camera degradations. Together, the VC and OBC processes have allowed MISR to achieve an absolute calibration uncertainty of 4% or better (la confidence level) for bright land targets. Additional fine-tunings have been made following analysis of lunar-view campaign data, and from a statistical analysis of Earth observations. These studies led to slight camera-to-camera adjustments, which are important in improving the aerosol retrieval process. Validation of the response at the lower end of the dynamic range has also been accomplished using a dark-water study. With these studies complete, MISR calibration is now in an operational mode, and data users can be assured the resulting data products are stable with time. Such records meet the needs of a program designed to support climate change and provide long-term monitoring of the Earth's atmosphere and radiative fluxes. (c) 2007 Elsevier Inc. All rights reserved. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. Instrument Design Engn Associates, Brea, CA USA. Northrop Grumman Space Technol, El Segundo, CA USA. RP Bruegge, CJ (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91125 USA. EM Carol.J.Bruegge@jpl.nasa.gov RI Kahn, Ralph/D-5371-2012 OI Kahn, Ralph/0000-0002-5234-6359 NR 29 TC 31 Z9 32 U1 1 U2 6 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD MAR 15 PY 2007 VL 107 IS 1-2 SI SI BP 2 EP 11 DI 10.1016/j.rse.2006.07.024 PG 10 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA 144XM UT WOS:000244829800002 ER PT J AU Lyapustin, A Wang, Y Kahn, R Xiong, J Ignatov, A Wolfe, R Wu, A Holben, B Bruegge, C AF Lyapustin, A. Wang, Y. Kahn, R. Xiong, J. Ignatov, A. Wolfe, R. Wu, A. Holben, B. Bruegge, C. TI Analysis of MODIS-MISR calibration differences using surface albedo around AERONET sites and cloud reflectance SO REMOTE SENSING OF ENVIRONMENT LA English DT Article DE MODIS; MISR; calibration; AERONET; surface albedo; cloud regression ID ON-ORBIT PERFORMANCE; ANGLE IMAGING SPECTRORADIOMETER; HIGH-RESOLUTION RADIOMETER; RADIATIVE-TRANSFER PROBLEM; GREENS-FUNCTION METHOD; OBSERVING SYSTEM; RETRIEVAL; ALGORITHM; SPECTROMETER; CHANNELS AB MODIS and MISR are two Earth Observing System instruments flown onboard the TerTa satellite. Their synergistic use could greatly benefit the broad user community by ensuring a global view of the Earth with high-quality products. A necessary condition for data fusion is radiometric calibration agreement between the two instruments. Earlier studies showed about 3% absolute radiometric difference between MISR and respective MODIS land bands in the visible and near-IR spectrum, which are also used in aerosol and cloud research. This study compared two surface albedo products derived from MODIS and MISR LIB data using the AERONET-based Surface Reflectance Validation Network (ASRVN). The ASRVN shows a positive MISR-MODIS albedo bias of + (0.01-0.03). Cross-sensor calibration inconsistencies were identified as a primary cause of the albedo biases. To establish an independent MODIS-MISR calibration link, top-of-atmosphere MODIS and MISR reflectances were regressed against each other over liquid water clouds. The empirical regression results have been adjusted for the differences in the respective MISR and MODIS spectral responses using radiative transfer simulations. The MISR-MODIS band gain differences for the top-of-atmosphere reflectance estimated with this technique are +6.0% in the Blue, +3.3% in the Green, +2.7% in the Red, and +0.8% in the NIR band. Applying the derived values to rescale the MODIS or MISR LIB data is shown to significantly reduce the cross-sensor ASRVN surface albedo biases. An absolute calibration scale for both sensors could be established based on independent ground-based measurements of the surface albedo at selected AERONET sites. (c) 2006 Elsevier Inc. All rights reserved. C1 Univ Maryland Baltimore Cty, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NASA, Jet Prop Lab, Pasadena, CA 91109 USA. NOAA, Camp Springs, MD 20746 USA. Sci Syst & Applicat Inc, Lanham, MD 20706 USA. RP Lyapustin, A (reprint author), Univ Maryland Baltimore Cty, Mail Code 614-4, Greenbelt, MD 20771 USA. EM Alexei.l.Lyapustin.1@gsfc.nasa.gov RI Ignatov, Alexander/F-5594-2010; Wolfe, Robert/E-1485-2012; Lyapustin, Alexei/H-9924-2014; Kahn, Ralph/D-5371-2012 OI Ignatov, Alexander/0000-0002-7463-5944; Wolfe, Robert/0000-0002-0915-1855; Lyapustin, Alexei/0000-0003-1105-5739; Kahn, Ralph/0000-0002-5234-6359 NR 42 TC 27 Z9 27 U1 0 U2 5 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0034-4257 EI 1879-0704 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD MAR 15 PY 2007 VL 107 IS 1-2 SI SI BP 12 EP 21 DI 10.1016/j.rse.2006.09.028 PG 10 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA 144XM UT WOS:000244829800003 ER PT J AU Jovanovic, V Moroney, C Nelson, D AF Jovanovic, Veljko Moroney, Catherine Nelson, David TI Multi-angle geometric processing for globally geo-located and co-registered MISR image data SO REMOTE SENSING OF ENVIRONMENT LA English DT Article DE calibration; geometric; global; mapping; orthorectification; cloud motion winds; photogrammetry AB This paper focuses on the high accuracy geo-location and co-registration performance operationally obtained for the Multi-angle Imaging SpectroRadiometer (MISR) data via a robust production algorithm. The MISR instrument (which is part of the payload for NASA's Terra spacecraft) continuously acquires systematic, global, multi-angle imagery in reflected sunlight since it was launched in December 1999, with the objective of supporting ecology and climate studies. The moderate resolution data need to be autonomously geo-rectified prior to being used in subsequent scientific retrievals. This is particularly critical to the unique cloud height/wind retrievals which require sub-pixel co-registration accuracies on a global basis. In order to address this problem, the MISR ground data processing system is based on a fully photograrnmetric approach and is complemented with a quality monitoring system used to verify performance globally and over desired time periods. The georectification requirements were developed from a series of data quality investigations based partially on sensitivity requirements for the cloud height/wind retrieval algorithm. An update to the nominal production algorithm has been implemented, and the final operational results are presented in this paper. (c) 2006 Elsevier Inc. All rights reserved. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Jovanovic, V (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM Veljko.Jovanovic@jpl.nasa.gov NR 14 TC 14 Z9 15 U1 0 U2 3 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD MAR 15 PY 2007 VL 107 IS 1-2 SI SI BP 22 EP 32 DI 10.1016/j.rse.2006.08.013 PG 11 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA 144XM UT WOS:000244829800004 ER PT J AU Liu, Y Franklin, M Kahn, R Koutrakis, P AF Liu, Yang Franklin, Meredith Kahn, Ralph Koutrakis, Petros TI Using aerosol optical thickness to predict ground-level PM2.5 concentrations in the St. Louis area: A comparison between MISR and MODIS SO REMOTE SENSING OF ENVIRONMENT LA English DT Article DE MISR; MODIS; aerosol optical thickness; AOT; PM2.5; particulate matter; statistical analysis; general linear model; terra satellite; St. Louis; particle health effects ID LIGHT-SCATTERING MEASUREMENTS; TROPOSPHERIC AEROSOLS; RELATIVE-HUMIDITY; AIR-POLLUTION; SATELLITE; MORTALITY; FINE; VALIDATION; QUALITY; DEPTH AB Using two general linear regression models, we compared the ability of the aerosol optical thickness (AOT) retrieved by the Multiangle Imaging SpectroRadiometer (MISR) and the Moderate Resolution Imaging Spectroradiometer (MODIS) to predict ground-level PM2.5 concentrations in St. Louis, MO and its surrounding areas. The models included meteorological parameters obtained from the National Oceanic and Atmospheric Administration (NOAA)'s Rapid Update Cycle (RUC20) model as covariates. Both MISR and MODIS AOT values were highly significant predictors Of PM2.5 concentrations. The MISR and MODIS models have overall comparable predictability of ground-level PM2.5 concentrations. The MISR model explained a slightly greater percentage (62%) of the variability in PM2.5 concentrations than the MODIS model (51%), and thus was a better fit. Over the entire data range, the MISR model underpredicts PM2.5 concentrations by approximately 12%, whereas the MODIS model underpredicts PM2.5 concentrations by approximately 18%. This underestimation occurred primarily at higher PM2.5 concentrations in both models. The regression coefficients from two models were highly comparable, suggesting that combining MISR and MODIS AOT data might benefit from the higher predicting accuracy of MISR and the better spatial coverage of MODIS. The newly developed particle size/shape indicators in MISR and MODIS aerosol product did not significantly improve our ability to predict PM2.5 concentrations using AOT measurements. Finally, using hourly PM2.5 concentrations did not seem to improve its association with AOT for the current study region. (c) 2006 Elsevier Inc. All rights reserved. C1 Harvard Univ, Sch Publ Hlth, Boston, MA 02215 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Liu, Y (reprint author), Harvard Univ, Sch Publ Hlth, 665 Huntington Ave, Boston, MA 02215 USA. EM yangliu@hsph.harvard.edu RI Kahn, Ralph/D-5371-2012; Wang, Linden/M-6617-2014 OI Kahn, Ralph/0000-0002-5234-6359; NR 29 TC 108 Z9 125 U1 5 U2 64 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0034-4257 EI 1879-0704 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD MAR 15 PY 2007 VL 107 IS 1-2 SI SI BP 33 EP 44 DI 10.1016/j.rse.2006.05.022 PG 12 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA 144XM UT WOS:000244829800005 ER PT J AU Kalashnikova, OV Mills, FP Eldering, A Anderson, D AF Kalashnikova, Olga V. Mills, Franklin P. Eldering, Annmarie Anderson, Don TI Application of satellite and ground-based data to investigate the UV radiative effects of Australian aerosols SO REMOTE SENSING OF ENVIRONMENT LA English DT Article DE Australian aerosols; UV surface irradiances; MISR; MODIS ID SOLAR ULTRAVIOLET-RADIATION; EARTHS SURFACE; SENSITIVITY; INDEX; OCEAN AB An understanding of the effect of aerosols on biologically- and photochemically-active UV radiation reaching the Earth's surface is important for many ongoing climate, biophysical, and air pollution studies. In particular, estimates of the UV characteristics of the most common Australian aerosols will be valuable inputs to UV Index forecasts, air quality studies, and assessments of the impact of regional environmental changes. By analyzing climatological distributions of Australian aerosols we have identified sites where co-located ground-based UV-B and ozone measurements were available during episodes of relatively high aerosol activity. Since at least June 2003, surface tN global irradiance spectra (285-450 nm) have been measured routinely at Darwin and Alice Springs in Australia by the Australian Bureau of Meteorology (BoM). Using colocated sunphotometer measurements at Darwin and Alice Springs, we identified several episodes of relatively high aerosol activity. Aerosol air mass types were analyzed from sunphotometer-derived angstrom parameter, MODIS fire maps and MISR aerosol property retrievals. To assess aerosol effects we compared the measured UV irradiances for aerosol-loaded and clear-sky conditions with each other and with irradiances simulated using the libRadtran radiative transfer model for aerosol-free conditions. We found that for otherwise similar atmospheric conditions, smoke aerosols over Darwin reduced the surface UV irradiance by as much as 40-50% at 290-300 nm and 20-25% at 320-400 nm near active fires (aerosol optical depth, AOD, at 500 nm similar to 0.6). Downwind of fires, the smoke aerosols over Darwin reduced the surface irradiance by 1525% at 290-300 nm and similar to 10% at 320-350 nm (AOD at 500 nm similar to 0.2). The effect of smoke increased with decrease of wavelength and is strongest in the UV-B. The aerosol attenuation factors calculated for the selected cases suggest smoke over Darwin has an effect on surface 340380 nm irradiances that is comparable to that produced by smoke over Sub-Saharan Africa. Dust activity was very low at Alice Springs during 2004, therefore we were not able to identify strong dust events to fully assess the UV effect of dust. For the cases studied, smoke aerosols seem to produce a stronger reduction in surface LYV irradiances than dust aerosols. (c) 2006 Elsevier Inc. All rights reserved. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. Australian Natl Univ, Ctr Resource & Environm Studies, Canberra, ACT, Australia. Bur Meteorol, Melbourne, Vic, Australia. RP Kalashnikova, OV (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91125 USA. EM Olga.V.Kalashnikova@jpl.nasa.gov NR 39 TC 19 Z9 20 U1 0 U2 3 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD MAR 15 PY 2007 VL 107 IS 1-2 SI SI BP 65 EP 80 DI 10.1016/j.rse.2006.07.025 PG 16 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA 144XM UT WOS:000244829800008 ER PT J AU Sinyuk, A Dubovik, O Holben, B Eck, TF Breon, FM Martonchik, J Kahn, R Diner, DJ Vermote, EF Roger, JC Lapyonok, T Slutsker, I AF Sinyuk, Alexander Dubovik, Oleg Holben, Brent Eck, Tom F. Breon, Francois-Marie Martonchik, John Kahn, Ralph Diner, David J. Vermote, Eric F. Roger, Jean-Claude Lapyonok, Tatyana Slutsker, Ilya TI Simultaneous retrieval of aerosol and surface properties from a combination of AERONET and satellite data SO REMOTE SENSING OF ENVIRONMENT LA English DT Article DE surface reflectance; aerosol properties; AERONET; MISR; MODIS; POLDER ID RESOLUTION IMAGING SPECTRORADIOMETER; SKY RADIANCE MEASUREMENTS; OPTICAL-PROPERTIES; BIDIRECTIONAL REFLECTANCE; ATMOSPHERIC CORRECTION; TROPOSPHERIC AEROSOLS; NADIR REFLECTANCE; DUST AEROSOLS; GOCART MODEL; BRDF MODELS AB We present a method for simultaneously retrieving aerosol and surface parameters from ground-based and satellite observations collocated in space and time. We show that a combination of down and up-looking observations provides sufficient measurement constraints for characterizing both aerosol and surface properties with minimal assumptions. In order to employ this concept in AERONET processing, the standard inverse algorithm [Dubovik, O. & King, M. D. (2000), A flexible inversion algorithm for retrieval of aerosol optical properties from sun and sky radiance measurements. Journal of Geophysical Research, 105, 20673-20696] has been modified to retrieve surface reflectance in addition to aerosol parameters when co-incident satellite measurements are available. The method was applied to observations of smoke and desert dust over the Mongu (Zambia) and Solar Village (Saudi Arabia) AERONET sites respectively. The AERONET data were complemented by available observations from the MISR, MODIS, and POLDER-2 satellite sensors. The retrieved bidirectional reflectance factor (BRF) and surface albedo comparison shows good agreement between results obtained using observations from different satellites. The robustness of the method is tested by analyzing surface albedo time series retrieved during periods of high aerosol optical depth variability and low seasonal changes in surface reflectance. The analysis shows that the performance of retrieval algorithm is stable under different aerosol loadings. It is shown that much of the observed surface albedo temporal variability could be attributed mostly to the combined uncertainty in satellite radiometric calibration and aerosol vertical distribution for Mongu and to differences in satellite angular sampling on different days for Solar Village. The sensitivity of surface retrievals to assumptions on aerosol vertical distribution and aerosol particle shape are analyzed. It is found that the maximum error in retrieved surface albedo at 0.44 mu m is 0.035 for aerosol optical depth 0.85 at 0.44 mu m. For aerosol optical depths lower than -0.7 the error in retrieved surface albedo is less than 0.02. Analysis of particle shape assumptions on surface retrievals showed that aerosol particle non-sphericity significantly affects the angular shape of BRF, but not the surface albedo. Finally, the sensitivity of AERONET aerosol retrievals to uncertainty in assumed surface reflectance is analyzed by comparing aerosol retrievals obtained with different surface assumptions. It is found that the uncertainty in surface reflectance model employed in the version I AERONET operational algorithm is larger than was previously assumed in [Dubovik, O., Smimov, A., Holbert, B. N., King, M. D., Kaufman, Y. J., Eck, T. F., & Slutsker, 1. (2600), Accuracy assessment of aerosol optical properties retrieved from AERONET sun and sky radiance measurements. Journal of Geophysical Research, 105, 9791-9806] and may have more significant effect on the retrieved aerosol properties than was documented in that work. In particular, larger errors were encountered for the real part of the refractive index (-0.05-0.07 increase) and maximum of the particle size distribution (similar to 20% decrease) retrievals for the Mongu case, when the aerosol optical depth was relatively small (similar to 0.4 at 0.44 mu m). The retrieved single scattering albedo uncertainties were within the error bars (0.03) estimated in [Dubovik, O., Smimov, A., Holbert, B. N., King, M. D., Kaufman, Y. J., Eck, T. F., & Slutsker, I. (2000), Accuracy assessment of aerosol optical properties retrieved from AERONET sun and sky radiance measurements. Journal of Geophysical Research, 105, 9791-9806], with the exception of the 0.44 mu m retrievals for the desert dust case when they increased by - 0.09 and 0.07 for low and high aerosol loadings respectively. (c) 2006 Elsevier Inc. All rights reserved. C1 NASA, Goddard Space Flight Ctr, Terr Phys Lab, Greenbelt, MD 20771 USA. Sci Syst & Applicat Inc, Lanham, MD USA. Univ Maryland Baltimore Cty, GEST Ctr, Baltimore, MD 21228 USA. Lab Sci Climat & Environm, Gif Sur Yvette, France. CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. Univ Maryland, College Pk, MD 20742 USA. RP Sinyuk, A (reprint author), NASA, Goddard Space Flight Ctr, Terr Phys Lab, Greenbelt, MD 20771 USA. EM asiniuk@ltpmail.gsfc.nasa.gov RI Dubovik, Oleg/A-8235-2009; ECK, THOMAS/D-7407-2012; Vermote, Eric/K-3733-2012; Kahn, Ralph/D-5371-2012; Breon, Francois-Marie/M-4639-2016 OI Dubovik, Oleg/0000-0003-3482-6460; Kahn, Ralph/0000-0002-5234-6359; Breon, Francois-Marie/0000-0003-2128-739X NR 76 TC 48 Z9 50 U1 5 U2 26 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0034-4257 EI 1879-0704 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD MAR 15 PY 2007 VL 107 IS 1-2 SI SI BP 90 EP 108 DI 10.1016/j.rse.2006.07.022 PG 19 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA 144XM UT WOS:000244829800010 ER PT J AU Mazzoni, D Logan, JA Diner, D Kahn, R Tong, LL Li, QB AF Mazzoni, Dominic Logan, Jennifer A. Diner, David Kahn, Ralph Tong, Lingling Li, Qinbin TI A data-mining approach to associating MISR smoke plume heights with MODIS fire measurements SO REMOTE SENSING OF ENVIRONMENT LA English DT Article DE MISR; MODIS; smoke plumes; boreal fires; injection height; aerosol transport; data mining; support vector machines; neural networks ID IMAGING SPECTRORADIOMETER MISR; CLIMATE-CHANGE; FOREST-FIRES; TRANSPORT; CONVECTION; RETRIEVAL; WILDFIRES AB Satellites provide unique perspectives on aerosol global and regional spatial and temporal distributions, and offer compelling evidence that visibility and air quality are affected by particulate matter transported over long distances. The heights at which emissions are injected into the atmosphere are major factors governing downwind dispersal. In order to better understand the environmental factors determining injection heights of smoke plumes from wildfires, we have developed a prototype system for automatically searching through several years of MISR and MODIS data to locate fires and the associated smoke plumes and to retrieve injection heights and other relevant measurements from them. We are refining this system and assembling a statistical database, aimed at understanding how injection height relates to the fire severity and local weather conditions. In this paper we focus on our working proof-of-concept system that demonstrates how machine-leaming and data mining methods aid in processing of massive volumes of satellite data. Automated algorithms for distinguishing smoke from clouds and other aerosols, identifying plumes, and extracting height data are described. Preliminary results are presented from application to MISR and MODIS data collected over North America during the summer of 2004. (c) 2006 Elsevier Inc. All rights reserved. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. Harvard Univ, Div Engn & Appl Sci, Cambridge, MA 02138 USA. Univ Texas, Dept Comp Sci, Austin, TX 78712 USA. RP Mazzoni, D (reprint author), Google Inc, 604 Arizona Ave, Santa Monica, CA 90401 USA. EM dominic@minorninth.com RI Kahn, Ralph/D-5371-2012 OI Kahn, Ralph/0000-0002-5234-6359 NR 28 TC 45 Z9 47 U1 3 U2 14 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD MAR 15 PY 2007 VL 107 IS 1-2 SI SI BP 138 EP 148 DI 10.1016/j.rse.2006.08.014 PG 11 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA 144XM UT WOS:000244829800013 ER PT J AU Mazzoni, D Garay, MJ Davies, R Nelson, D AF Mazzoni, Dominic Garay, Michael J. Davies, Roger Nelson, David TI An operational MISR pixel classifier using support vector machines SO REMOTE SENSING OF ENVIRONMENT LA English DT Article DE MISR; multi-angle; support vector machines; supervised classification; neural networks ID PROBABILISTIC NEURAL-NETWORK; CLOUD-TYPE CLASSIFICATION; AVHRR IMAGERY; RETRIEVAL; SURFACE AB The Multi-angle Imaging SpectroRadiometer (MISR) data products now include a scene classification for each 1.1-km, pixel that was developed using Support Vector Machines (SVMs), a cutting-edge machine learning technique for supervised classification. Using a combination of spectral, angular, and texture features, each pixel is classified as land, water, cloud, aerosol, or snowlice, with the aerosol class further divided into smoke, dust, and other aerosols. The classifier was trained by MISR scientists who labeled hundreds of scenes using a custom interactive tool that showed them the results of the training in real time, making the process significantly faster. Preliminary validation shows that the accuracy of the classifier is approximately 81% globally at the 1.1-km pixel level. Applications of this classifier include global studies of cloud and aerosol distribution, as well as data mining applications such as searching for smoke plumes. This is one of the largest and most ambitious operational uses of machine learning techniques for a remote-sensing instrument, and the success of this system will hopefully lead to further use of this approach. (c) 2006 Elsevier Inc. All rights reserved. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Mazzoni, D (reprint author), Google Inc, 604 Arizona Ave, Santa Monica, CA 90401 USA. EM dominic@minorninth.com RI Davies, Roger/D-4296-2009 OI Davies, Roger/0000-0002-2991-0409 NR 33 TC 25 Z9 30 U1 0 U2 2 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD MAR 15 PY 2007 VL 107 IS 1-2 SI SI BP 149 EP 158 DI 10.1016/j.rse.2006.06.021 PG 10 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA 144XM UT WOS:000244829800014 ER PT J AU Yang, YK Di Girolamo, L Mazzoni, D AF Yang, Yuekui Di Girolamo, Larry Mazzoni, Dominic TI Selection of the automated thresholding algorithm for the Multi-angle Imaging SpectroRadiometer Radiometric Camera-by-Camera Cloud Mask over land SO REMOTE SENSING OF ENVIRONMENT LA English DT Article DE MISR; cloud detection; automated threshold selection algorithm; daytime cloud mask ID FUZZY-SETS; ENTROPY; HISTOGRAM; MISR; SEGMENTATION; CLASSIFICATION; INSTRUMENT; RADIANCES; FRACTION AB The Radiometric Camera-by-Camera Cloud Mask (RCCM) is archived at the NASA Langley Distributed Active Archive Center as one of the standard products from the Multi-angle Imaging SpectroRadiometer (MISR) mission. The RCCM algorithm applied over land surfaces uses an Automated Threshold Selection Algorithm (ATSA) to derive thresholds that are applied to a cloud masking test to determine whether a given image pixel is clear or contains cloud. In this article, we established a framework for the selection of ATSA and the cloud masking tests, which is not only suitable for the RCCM over land, but cloud detection for other satellite missions. Using this framework, we have under-taken the largest comparison of existing histogram-based ATSAs (16 in total) and applied them to four cloud masking tests that can be constructed from the MISR radiances, namely the red channel bidirectional reflectance function (BRF), the standard deviation (STDV) of the red channel BRF, the normalized difference vegetation index (NDVI), and a parameter D that is constructed by optimizing the information from NDV1 and red channel BR-F for cloud detection. The cloud masking tests and ATSAs are applied to 35 MISR scenes from six snow-free land surface types. To evaluate their performances reference cloud masks are constructed for the 35 scenes using interactive, supervised learning, visualization software. Independent of the ATSA and as a single cloud masking test, D performed the best in terms of having the lowest misclassification rate using the best possible threshold, the highest bimodal rate in the shape of the histograms derived from the 35 scenes, and the least sensitivity to errors in the choice of threshold. Of the 16 ATSAs, the methods of Li and Lee [Li, C.H., and Lee, C.K., (1993). Minimum cross-entropy thresholding. Pattern Recognition, 26(4), 617-625.] and Pal and Bhandari [Pal, N. R., and Bhandari, D., (1993). Image thresholding: some new techniques. Signal Processing, 33, 139-158.] performed the best when applied to D, with essentially unbiased performance and a root mean square of 15% when compared to cloud masks using the best possible thresholds. It is recommended that increased perfon-nance of the RCCM-land algorithm can be had through an increase in the space-time sampling used to generate histograms of D and the addition of a STDV cloud masking test to improve the detection of small cumulus clouds. (c) 2006 Elsevier Inc. All rights reserved. C1 Univ Illinois, Dept Atmospher Sci, Urbana, IL 61801 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Yang, YK (reprint author), Univ Illinois, Dept Atmospher Sci, 105 S Gregory Ave, Urbana, IL 61801 USA. EM yuekui@atmos.uiuc.edu RI Yang, Yuekui/B-4326-2015 NR 44 TC 15 Z9 15 U1 1 U2 7 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD MAR 15 PY 2007 VL 107 IS 1-2 SI SI BP 159 EP 171 DI 10.1016/j.rse.2006.05.020 PG 13 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA 144XM UT WOS:000244829800015 ER PT J AU Shi, T Clothiaux, EE Yu, B Braverman, AJ Groff, DN AF Shi, Tao Clothiaux, Eugene E. Yu, Bin Braverman, Amy J. Groff, David N. TI Detection of daytime arctic clouds using MISR and MODIS data SO REMOTE SENSING OF ENVIRONMENT LA English DT Article DE polar study; cloud detection; MISR; MODIS ID MULTI-ANGLE; CLEAR-SKY; RADIOMETER; RADIANCES AB Expert labels were used to evaluate arctic cloud detection accuracies of several methods based on MISR angular radiances and MODIS spectral radiances. The accuracy of cloud detections was evaluated relative to 5.086 million expert labels applied to 7.114 million 1.1-km resolution pixels with valid radiances from 57 scenes. The accuracy of the MODIS operational cloud mask was 90.72% for the 32 partly cloudy scenes and 93.37% for the 25 completely clear and overcast scenes. An automated, simple threshold algorithm based on three features extracted from MISR radiances and the MODIS operational cloud mask agreed with each other for 74.91% of the pixels in the 32 partly cloudy scenes and 78.44% of the pixels in the 25 completely clear and overcast scenes. These subsets of pixels had, relative to the expert labels, classification accuracies of 96.53% for the 32 partly cloudy scenes and 99.05% for the 25 completely clear and overcast scenes. Fisher's quadratic discriminate analysis (QDA) trained on expert labels from the 32 partly cloud scenes was applied to MISR radiances, three features based on MISR radiances, MODIS radiances, and the six features of the MODIS operational cloud mask with accuracies ranging from 87.51% to 96.43%. Accuracies increased to about 97% when QDA with expert labels was applied to combined radiances or features from both MISR and MODIS. Operational QDA-based classifiers were developed using as training labels those pixels for which the MISR automated, simple threshold and MODIS operational cloud mask algorithms agreed. Training the QDA classifier on these automatic labels using MISR radiances, three features based on MISR radiances, MODIS radiances, and the six features of the MODIS operational cloud mask led to accuracies ranging from 85.23% to 93.62% for the 32 partly cloudy scenes. Classification accuracies increased to 93.74% (93.40%) when combined MISR and MODIS radiances (features) were used. The highest accuracy attained with any operational algorithm tested on all 57 scenes was 94.51%. These results suggest that both MISR and MODIS radiances are sufficient for cloud detection in daytime polar regions. (c) 2006 Elsevier Inc. All rights reserved. C1 Ohio State Univ, Dept Stat, Columbus, OH 43210 USA. Penn State Univ, Dept Meteorol, University Pk, PA 16802 USA. Univ Calif Berkeley, Dept Stat, Berkeley, CA 94720 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Dept Energy, Billings, OK 74630 USA. RP Shi, T (reprint author), Ohio State Univ, Dept Stat, Columbus, OH 43210 USA. EM taoshi@stat.ohio-state.edu; cloth@meteo.psu.edu; binyu@stat.berkeley.edu; Amy.Braverman@jpl.nasa.gov; d_groff@ops.sgp.arm.gov NR 21 TC 10 Z9 10 U1 0 U2 6 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD MAR 15 PY 2007 VL 107 IS 1-2 SI SI BP 172 EP 184 DI 10.1016/j.rse.2006.10.015 PG 13 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA 144XM UT WOS:000244829800016 ER PT J AU Davies, R Horvath, A Moroney, C Zhang, BL Zhu, YQ AF Davies, Roger Horvath, Akos Moroney, Catherine Zhang, Banglin Zhu, Yanqiu TI Cloud motion vectors from MISR using sub-pixel enhancements SO REMOTE SENSING OF ENVIRONMENT LA English DT Article DE cloud motion vector; atmospheric motion vector; multi-angle remote sensing; height-resolved wind; geometric cloud height; stereo matching; wind remote sensing AB The operational retrieval of height-resolved cloud motion vectors by the Multiangle Imaging SpectroRadiometer on the Terra satellite has been significantly improved by using sub-pixel approaches to co-registration and disparity assessment, and by imposing stronger quality control based on the agreement between independent forward and aft triplet retrievals. Analysis of the fore-aft differences indicates that CMVs pass the basic operational quality control 67% of the time, with rms differences - in speed of 2.4 m/s, in direction of 17 degrees, and in height assignment of 290 m. The use of enhanced quality control thresholds reduces these rms values to 1.5 m/s, 14 degrees and 165 m, respectively, at the cost of reduced coverage to 45%. Use of the enhanced thresholds also eliminates a tendency for the rms differences to increase with height. Comparison of CMVs from an earlier operational version that had slightly weaker quality control, with 6-hour forecast winds from the Global Modeling and Assimilation Office yielded very low bias values and an rms vector difference that ranged from 5 m/s for-low clouds to 10 m/s for high clouds. (c) 2007 Elsevier Inc. All rights reserved. C1 Univ Auckland, Dept Phys, Auckland 1, New Zealand. Univ Miami, Rosenstiel Sch Marine & Atmospher Sci, Miami, FL 33149 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. NASA, Goddard Space Flight Ctr, Global Modeling & Assimilat Off, Greenbelt, MD 20771 USA. RP Davies, R (reprint author), Univ Auckland, Dept Phys, Auckland 1, New Zealand. EM r.davies@auckland.ac.nz RI Horvath, Akos/A-2453-2008; Davies, Roger/D-4296-2009 OI Horvath, Akos/0000-0002-5860-2368; Davies, Roger/0000-0002-2991-0409 NR 6 TC 22 Z9 23 U1 0 U2 3 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD MAR 15 PY 2007 VL 107 IS 1-2 SI SI BP 194 EP 199 DI 10.1016/j.rse.2006.09.023 PG 6 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA 144XM UT WOS:000244829800018 ER PT J AU Naud, CM Baum, BA Pavolonis, M Heidinger, A Frey, R Zhang, H AF Naud, C. M. Baum, B. A. Pavolonis, M. Heidinger, A. Frey, R. Zhang, H. TI Comparison of MISR and MODIS cloud-top heights in the presence of cloud overlap SO REMOTE SENSING OF ENVIRONMENT LA English DT Article DE cloud; overlap; MISR; MODIS; cloud-top height; cloud type ID CIRRUS CLOUD; DAYTIME; INSTRUMENT; MISSION; AVHRR; VIIRS AB Coincident MISR and MODIS cloud-top heights retrieved above two vertically pointing radar sites (ARM-SGP and UK-CFARR) are compared for 54 scenes between March 2000 and October 2003. The difference between MODIS and MISR cloud-top heights is assessed in situations where multiple cloud layers are present in a vertical column (i.e., cloud overlap or multilayered cloud). MISR stereo cloud-top heights are known to be sensitive to low-level clouds of high contrast (between two camera views) even if high clouds with a wide range of optical thicknesses are also present in the scene. MODIS retrieved cloud-top heights do not experience this problem as long as the highest cloud layer has a visible optical thickness greater than approximately 1. Consequently, the difference in cloud-top heights between MODIS and MISR is often large and positive in cloud overlap conditions. In cloud overlap conditions, small differences between MODIS and MISR cloud-top heights can be found where both instruments detect the highest cloud layer or, on the contrary, where they both fail to detect the highest cloud but instead detect some lower level cloud. The comparison with radar cloud-top heights on a 2 1 -scene subset confirmed that large differences are associated with cloud overlap, but also showed that small differences can be found in similar situations if the highest layer is of large contrast (both instruments detect the highest cloud layer) or of extremely small optical thickness (both instruments fail to detect the highest cloud layer). With the use of a cloud-typing technique applied to MODIS data that can also identify areas containing cloud overlap, small differences were found to occur for 60-70% of all overlap pixels examined here, highlighting the weakness of using the MODIS-MISR cloud-top height differences as a sole indicator for automated cloud overlap detection. While the accuracy of the MODIS cloud-top pressure/height algorithm decreases as the cirrus optical thickness becomes less than 1, the MISR approach may still be able to infer an accurate cloud-top height depending on the cloud contrast between two view angles. However, synergy between the difference in MODIS-MISR cloud-top height analysis and the MODIS cloudtyping method could improve overlap detection for thin cirrus over low cloud situations and provide additional information on the cloud-top height of two distinct layers. (c) 2006 Elsevier Inc. All rights reserved. C1 Columbia Univ, GISS, Dept Appl Phys & Appl Math, New York, NY 10025 USA. NASA, Langley Res Ctr, Hampton, VA 23665 USA. Univ Wisconsin, CIMSS, Madison, WI 53706 USA. RP Naud, CM (reprint author), Columbia Univ, GISS, Dept Appl Phys & Appl Math, 2880 Broadway, New York, NY 10025 USA. EM cnaud@giss.nasa.gov RI Heidinger, Andrew/F-5591-2010; Pavolonis, Mike/F-5618-2010; Baum, Bryan/B-7670-2011 OI Heidinger, Andrew/0000-0001-7631-109X; Pavolonis, Mike/0000-0001-5822-219X; Baum, Bryan/0000-0002-7193-2767 NR 27 TC 13 Z9 13 U1 1 U2 11 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD MAR 15 PY 2007 VL 107 IS 1-2 SI SI BP 200 EP 210 DI 10.1016/j.rse.2006.09.030 PG 11 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA 144XM UT WOS:000244829800019 ER PT J AU Fox, D Gonzalez, E Kahn, R Martonchik, J AF Fox, David Gonzalez, Enrique Kahn, Ralph Martonchik, John TI Near-surface wind speed retrieval from space-based, multi-angle imaging of ocean sun glint patterns SO REMOTE SENSING OF ENVIRONMENT LA English DT Article DE sun glint; ocean wind speed; multi-angle remote sensing; MISR; aerosol retrieval ID SPECTRAL REFLECTANCE; AEROSOL PROPERTIES; WHITECAPS AB The relationship between the MISR multi-angle observations of sun glint pattern width over ocean and the near-surface wind speed is explored. With this relationship, we develop an algorithm that can constrain the standard, wind-driven glint/white cap model that defines the ocean-surface boundary condition in MISR aerosol retrievals. The key geometric factor determining wind retrieval quality is the angular distance between the reflection vector and the closest MISR multi-angle observation - the minimum Sun Glint Angle (SGA). MISR-retrieved winds are within 2.4 m/s of buoy-measured values for minimum SGA below about 15 degrees for the 38 cases studied, and usually better than 1.1 m/s, except one for which the wind speed was extremely low. For minimum SGA above about 15 degrees, MISR angular glint pattern reflectance sampling is not adequate to perform wind retrievals. An ambiguity in the retrieval that can occur for minimum SGA greater than 6 degrees or 7 degrees is resolved by the minimum observed absolute reflectance. We also confirm the high accuracy of the Cox-Munk ocean surface reflectance model, used to analyze the glint pattern dependence on wind speed. The wind-retrieval method could be used in an operational multi-angle aerosol retrieval algorithm to dynamically constrain the ocean surface boundary condition when glint pattern angular sampling is adequate. (c) 2007 Elsevier Inc. All rights reserved. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Glendale Coll, Glendale, CA USA. RP Kahn, R (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM Ralph.Kahn@jpl.nasa.gov RI Kahn, Ralph/D-5371-2012 OI Kahn, Ralph/0000-0002-5234-6359 NR 8 TC 5 Z9 6 U1 1 U2 5 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD MAR 15 PY 2007 VL 107 IS 1-2 SI SI BP 223 EP 231 DI 10.1016/j.rse.2006.10.021 PG 9 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA 144XM UT WOS:000244829800021 ER PT J AU Bills, BG Borsa, AA Comstock, RL AF Bills, Bruce G. Borsa, Adrian A. Comstock, Robert L. TI MISR-based passive optical bathymetry from orbit with few-cm level of accuracy on the Salar de Uyuni, Bolivia SO REMOTE SENSING OF ENVIRONMENT LA English DT Review DE MISR; topography; bathymetry; passive optical; Salar de Uyuni ID IMAGING SPECTRORADIOMETER MISR; PLEISTOCENE LAKE BONNEVILLE; SOUTH-AMERICAN ALTIPLANO; ADRIATIC COASTAL WATERS; CENTRAL ANDES; GEOCHEMICAL EVOLUTION; REFRACTIVE-INDEX; CLIMATE-CHANGE; SALINE LAKES; DE-ATACAMA AB We demonstrate that, under ideal circumstances, passive optical measurements can yield surface water depth estimates with an accuracy of a few centimeters. Our target area is the Salar de Uyuni, in Bolivia. It is a large, active salt flat or playa, which is maintained as an almost perfectly le vel and highly reflective surface by annual flooding, to a mean depth of 30-50 cm. We use MISR data to estimate spatial and temporal variations in water depth during the waning portion of the 2001 flooding cycle. We use a single ICESat laser altimetry profile to calibrate our water depth model.-Though the salt surface is probably the smoothest surface of its size on Earth, with less that 30 cm RMS height variations over an area of nearly 10(4) km(2), it is not completely featureless. Topography there includes a peripheral depression, or moat, around the edge of the salt, and several sets of prominent parallel ridges, with 5 km wavelength and 30 cm amplitude. The process by which these features form is still not well characterized. (c) 2006 Elsevier Inc. All rights reserved. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Scripps Inst Oceanog, La Jolla, CA USA. RP Bills, BG (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. EM bbills@ucsd.edu RI Bills, Bruce/C-1156-2008 NR 106 TC 9 Z9 9 U1 0 U2 7 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD MAR 15 PY 2007 VL 107 IS 1-2 SI SI BP 240 EP 255 DI 10.1016/j.rse.2006.11.006 PG 16 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA 144XM UT WOS:000244829800023 ER PT J AU Garay, MJ Diner, DJ AF Garay, Michael J. Diner, David J. TI Multi-angle Imaging SpectroRadiometer (MISR) time-lapse imagery of tsunami waves from the 26 December 2004 Sumatra-Andaman earthquake SO REMOTE SENSING OF ENVIRONMENT LA English DT Article DE multi-angle remote sensing; terra; MISR; Asian tsunami; Sumatra-Andaman earthquake ID RUPTURE; INDIA; COAST; MODEL AB On 26 December 2004, a few hours after a massive earthquake occurred off the western coast of Sumatra in the Indian Ocean generating a major tsunami, the Multi-angle Imaging SpectroRadiometer (MISR) instrument on NASA's Terra satellite captured unique, time-lapse evidence of extremely large waves occurring along the eastern coast of India. The MISR imagery provides information on the location and characteristics of tsunami waves in near-shore waters, along with estimates of the wave speed. (c) 2006 Elsevier Inc. All rights reserved. C1 Univ Calif Los Angeles, Los Angeles, CA USA. CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Garay, MJ (reprint author), Univ Calif Los Angeles, Los Angeles, CA USA. EM Michael.J.Garay@jpl.nasa.gov NR 17 TC 10 Z9 10 U1 0 U2 1 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD MAR 15 PY 2007 VL 107 IS 1-2 SI SI BP 256 EP 263 DI 10.1016/j.rse.2006.10.022 PG 8 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA 144XM UT WOS:000244829800024 ER PT J AU Su, LH Chopping, MJ Rango, A Martonchik, JV Peters, DPC AF Su, Lihong Chopping, Mark J. Rango, Albert Martonchik, John V. Peters, Debra P. C. TI Support vector machines for recognition of semi-arid vegetation types using MISR multi-angle imagery SO REMOTE SENSING OF ENVIRONMENT LA English DT Article DE MISR; support vector machine; semi-arid vegetation; classification; multi-angle observations ID REFLECTANCE CSAR MODEL; BIDIRECTIONAL REFLECTANCE; CLASSIFICATION; SURFACE; AVHRR; BRDF AB Accurately mapping community types is one of the main challenges for monitoring and and semi-arid grasslands with remote sensing. The multi-angle approach has been proven useful for mapping vegetation types in desert grassland. The Multi-angle Imaging Spectro-Radiometer (MISR) provides 4 spectral bands and 9 angular reflectance. In this study, 44 classification experiments have been implemented to find the optimal combination of MISR multi-angular data to mine the information carried by MISR data as effectively as possible. These experiments show the following findings: 1) The combination of MISR's 4 spectral bands at nadir and red and near infrared bands in the C, B, and A cameras observing off-nadir can obtain the best vegetation type differentiation at the community level in New Mexico desert grasslands. 2) The k parameter at red band of Modified-Rahman-Pinty-Verstraete (MRPV) model and the structural scattering index (SSI) can bring useful additional information to land cover classification. The information carried by these two parameters, however, is less than that carried by surface anisotropy patterns described by the MRPV model and a linear semi-empirical kernel-driven bidirectional reflectance distribution function model, the RossThin-LiSparseMODIS (RTnLS) model. These experiments prove that: 1) multi-angular reflectance raise overall classification accuracy from 45.8% for nadir-only reflectance to 60.9%. 2) With surface anisotropy patterns derived from MRPV and RTnLS, an overall accuracy of 68.1% can be obtained when maximum likelihood algorithms are used. 3) Support Vector Machine (SVM) algorithms can raise the classification accuracy to 76.7%. This research shows that multi-angular reflectance, surface anisotropy patterns and SVM algorithms can improve desert vegetation type differentiation importantly. (c) 2006 Elsevier Inc.. All rights reserved. C1 Montclair State Univ, Dept Earth & Environm Studies, Montclair, NJ 07043 USA. USDA ARS, Jornada Expt Range, Las Cruces, NM 88003 USA. CALTECH, Jet Prop Lab, NASA, Pasadena, CA 91109 USA. RP Su, LH (reprint author), Montclair State Univ, Dept Earth & Environm Studies, Montclair, NJ 07043 USA. EM sul@mail.montclair.edu NR 29 TC 31 Z9 38 U1 2 U2 8 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD MAR 15 PY 2007 VL 107 IS 1-2 SI SI BP 299 EP 311 DI 10.1016/j.rse.2006.05.023 PG 13 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA 144XM UT WOS:000244829800028 ER PT J AU Hu, JN Su, Y Tan, B Huang, D Yang, WZ Schull, M Bull, MA Martonchik, JV Diner, DJ Knyazikhin, Y Myneni, RB AF Hu, Jiannan Su, Yin Tan, Bin Huang, Dong Yang, Wenze Schull, Mitchell Bull, Michael A. Martonchik, John V. Diner, David J. Knyazikhin, Yuri Myneni, Ranga B. TI Analysis of the MISR LA/FPAR product for spatial and temporal coverage, accuracy and consistency SO REMOTE SENSING OF ENVIRONMENT LA English DT Article DE MISR; leaf area index; fraction of photosynthetically active radiation absorved by vegetation; satellite product ID LEAF-AREA INDEX; PHOTOSYNTHETICALLY ACTIVE RADIATION; LAND BIOPHYSICAL PRODUCTS; MULTIANGLE SATELLITE DATA; INFORMATION-CONTENT; SOLAR-RADIATION; FPAR ALGORITHM; TIME-SERIES; MODIS; LAI AB The Multi-angle Imaging SpectroRadiometer (MISR) instrument provides global imagery at nine discrete viewing angles and four visible/near-infrared spectral bands. MISR standard products include green leaf area index (LAI) of vegetation and fraction of photosynthetically active radiation absorbed by vegetation (FPAR). This paper describes the research basis for transitioning the MISR LAI/FPAR products from provisional to validation status. The efforts included not only comparisons to field data but also analyses of relationships, consistency and complementarity between various MISR products derived by independent algorithms. For example, we show how the energy absorbed by the ground below vegetation can be estimated from two independent MISR products, FPAR and BHRPAR (bi-hemispheric reflectance at PAR wavelengths). Further, we show that this information can be used to derive at least three measures of canopy structure - Beer's law extinction coefficient, mean leaf inclination and the gap fraction or vegetation ground cover. The spatial and temporal coverage of the LAI/FPAR product is mainly limited by cloud contamination. However, when a successful aerosol retrieval is performed, typically 95% of pixels have surface reflectance retrievals suitable as input to the LAI/FPAR algorithm. The algorithm provides LAI/FPAR retrievals in 50-80% of these pixels with suitable input. The early versions of the algorithm overestimated LAI values in grasses and broadleaf crops. The MISR LAI product from the recalibrated algorithm (version 3.3) is assessed by comparison with field data collected in a 3 x 3 km agricultural area (grasses and cereal crops) near Avignon, France. LAI retrievals in other biomes are compared to MODIS LAI product of known accuracy. The MISR LAI product shows structural and phenological variability in agreement with data. Our results suggest that the product is accurate to within 0.66 LAI in herbaceous vegetation and savannas and is an overestimate by about 1 LAI in broadleaf forests. LAI retrievals over needle leaf forests remain at provisional quality level. (c) 2006 Elsevier Inc. All rights reserved. C1 Boston Univ, Dept Geog, Boston, MA 02215 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Knyazikhin, Y (reprint author), Boston Univ, Dept Geog, 675 Commonwealth Ave, Boston, MA 02215 USA. EM jknjazi@bu.edu RI Schull, Mitch/D-1663-2010; Yang, Wenze/B-8356-2012; Tan, Bin/G-1331-2012; Huang, Dong/H-7318-2014; Myneni, Ranga/F-5129-2012 OI Yang, Wenze/0000-0001-8514-2742; Huang, Dong/0000-0001-9715-6922; NR 42 TC 22 Z9 27 U1 2 U2 12 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD MAR 15 PY 2007 VL 107 IS 1-2 SI SI BP 334 EP 347 DI 10.1016/j.rse.2006.06.020 PG 14 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA 144XM UT WOS:000244829800031 ER PT J AU Chepfer, H Minnis, P Dubuisson, P Chiriaco, M Sun-Mack, S Riviere, ED AF Chepfer, H. Minnis, P. Dubuisson, P. Chiriaco, M. Sun-Mack, S. Riviere, E. D. TI Nitric acid particles in cold thick ice clouds observed at global scale: Link with lightning, temperature, and upper tropospheric water vapor SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID GENERAL-CIRCULATION MODEL; TROPICAL TROPOPAUSE; CIRRUS CLOUDS; RELATIVE-HUMIDITY; TRIHYDRATE; CLIMATE; AEROSOL; MODIS; DISTRIBUTIONS; STRATOSPHERE AB [1] Signatures of nitric acid particles (NAP) in cold thick ice clouds have been derived from satellite observations. Most NAP are detected in the tropics (9 to 20% of clouds with T < 202.5 K). Higher occurrences were found in the rare midlatitudes very cold clouds. NAP occurrence increases as cloud temperature decreases, and NAP are more numerous in January than July. Comparisons of NAP and lightning distributions show that lightning seems to be the main source of the NOx, which forms NAP in cold clouds over continents. Qualitative comparisons of NAP with upper tropospheric humidity distributions suggest that NAP may play a role in the dehydration of the upper troposphere when the tropopause is colder than 195 K. C1 Ecole Polytech, Lab Meteorol Dynam, Inst Pierre Simon Lapl, F-91128 Palaiseau, France. NASA, Langley Res Ctr, Hampton, VA 23681 USA. Univ Littoral, Lab Ecosyst Littoraux & Cotiers, F-62930 Wimereux, France. Sci Applicat Int Corp, Hampton, VA 23666 USA. Univ Orleans, CNRS, Lab Phys Chim Environm, F-45071 Orleans, France. RP Chepfer, H (reprint author), Ecole Polytech, Lab Meteorol Dynam, Inst Pierre Simon Lapl, Route Saclay, F-91128 Palaiseau, France. EM chepfer@lmd.polytechnique.fr RI Minnis, Patrick/G-1902-2010 OI Minnis, Patrick/0000-0002-4733-6148 NR 37 TC 5 Z9 5 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAR 14 PY 2007 VL 112 IS D5 AR D05212 DI 10.1029/2005JD006602 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 147QI UT WOS:000245017100001 ER PT J AU McPeters, RD Labow, GJ Logan, JA AF McPeters, Richard D. Labow, Gordon J. Logan, Jennifer A. TI Ozone climatological profiles for satellite retrieval algorithms SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID COLUMN OZONE; TRENDS AB [1] A new altitude-dependent ozone climatology has been produced for use with the version 8 Total Ozone Mapping Spectrometer (TOMS) and Solar Backscatter Ultraviolet retrieval algorithms. The climatology consists of monthly average ozone profiles for 10 degrees latitude zones covering altitudes from 0 to 60 km (in Z* pressure altitude coordinates). The climatology was formed by combining data from Stratospheric Aerosol and Gas Experiment II (SAGE II; 1988-2001) or Microwave Limb Sounder (MLS; 1991-1999) with data from balloon sondes (1988-2002). Ozone below 10 km is based on balloon sondes, whereas ozone at 19 km and above is based on SAGE II measurements. When SAGE data are not available (at high latitudes), MLS data are used. The ozone climatology in the southern hemisphere and tropics has been greatly improved in recent years by the addition of a large number of balloon sonde measurements made under the Southern Hemisphere Additional Ozonesondes program. The new climatology better represents the seasonal behavior of ozone in the troposphere, including the known hemispheric asymmetry, and in the upper stratosphere. A modification of this climatology was used for the TOMS version 8 retrieval that includes total ozone dependence, which is important in the lower stratosphere. Comparisons of TOMS ozone with ground stations show improved accuracy over previous TOMS retrievals due in part to the new climatology. C1 NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. Sci Syst & Applicat Inc, Lanham, MD 20706 USA. Harvard Univ, Div Engn & Appl Sci, Cambridge, MA 02138 USA. RP McPeters, RD (reprint author), NASA, Goddard Space Flight Ctr, Atmospheres Lab, Code 613-3, Greenbelt, MD 20771 USA. EM mcpeters@wrabbit.gsf.nasa.gov RI McPeters, Richard/G-4955-2013 OI McPeters, Richard/0000-0002-8926-8462 NR 19 TC 133 Z9 135 U1 0 U2 7 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAR 14 PY 2007 VL 112 IS D5 AR D05308 DI 10.1029/2005JD006823 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 147QI UT WOS:000245017100002 ER PT J AU Ott, LE Pickering, KE Stenchikov, GL Huntrieser, H Schumann, U AF Ott, Lesley E. Pickering, Kenneth E. Stenchikov, Georgiy L. Huntrieser, Heidi Schumann, Ulrich TI Effects of lightning NOx production during the 21 July European Lightning Nitrogen Oxides Project storm studied with a three-dimensional cloud-scale chemical transport model SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID PARAMETERIZATION; DISTRIBUTIONS; THUNDERSTORMS; CHEMISTRY; TRACER AB [1] The 21 July 1998 thunderstorm observed during the European Lightning Nitrogen Oxides Project (EULINOX) project was simulated using the three-dimensional Goddard Cumulus Ensemble (GCE) model. The simulation successfully reproduced a number of observed storm features including the splitting of the original cell into a southern cell which developed supercell characteristics and a northern cell which became multicellular. Output from the GCE simulation was used to drive an offline cloud-scale chemical transport model which calculates tracer transport and includes a parameterization of lightning NOx production which uses observed flash rates as input. Estimates of lightning NOx production were deduced by assuming various values of production per intracloud and production per cloud-to-ground flash and comparing the results with in-cloud aircraft observations. The assumption that both types of flashes produce 360 moles of NO per flash on average compared most favorably with column mass and probability distribution functions calculated from observations. This assumed production per flash corresponds to a global annual lightning NOx source of 7 Tg N yr(-1). Chemical reactions were included in the model to evaluate the impact of lightning NOx on ozone. During the storm, the inclusion of lightning NOx in the model results in a small loss of ozone (on average less than 4 ppbv) at all model levels. Simulations of the chemical environment in the 24 hours following the storm show on average a small increase in the net production of ozone at most levels resulting from lightning NOx, maximizing at approximately 5 ppbv day(-1) at 5.5 km. Between 8 and 10.5 km, lightning NOx causes decreased net ozone production. C1 Univ Maryland, Dept Atmospher & Ocean Sci, College Pk, MD 20742 USA. Rutgers State Univ, Dept Environm Sci, New Brunswick, NJ 08901 USA. Deutsches Zentrum Luft & Raumfahrt, Inst Phys Atmosphare, D-82230 Oberpfaffenhofen, Germany. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Ott, LE (reprint author), Univ Maryland, Dept Atmospher & Ocean Sci, College Pk, MD 20742 USA. EM leo@atmos.umd.edu RI Ott, Lesley/E-2250-2012; Pickering, Kenneth/E-6274-2012; Georgiy, Stenchikov/J-8569-2013; OI Schumann, Ulrich/0000-0001-5255-6869 NR 36 TC 36 Z9 37 U1 2 U2 13 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAR 14 PY 2007 VL 112 IS D5 AR D05307 DI 10.1029/2006JD007365 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 147QI UT WOS:000245017100003 ER PT J AU Li, L Wang, XF Sasidharan, R Stolc, V Deng, W He, H Korbel, J Chen, XW Tongprasit, W Ronald, P Chen, RS Gerstein, M Deng, XW AF Li, Lei Wang, Xiangfeng Sasidharan, Rajkumar Stolc, Viktor Deng, Wei He, Hang Korbel, Jan Chen, Xuewei Tongprasit, Waraporn Ronald, Pamela Chen, Runsheng Gerstein, Mark Deng, Xing Wang TI Global Identification and Characterization of Transcriptionally Active Regions in the Rice Genome SO PLOS ONE LA English DT Article AB Genome tiling microarray studies have consistently documented rich transcriptional activity beyond the annotated genes. However, systematic characterization and transcriptional profiling of the putative novel transcripts on the genome scale are still lacking. We report here the identification of 25,352 and 27,744 transcriptionally active regions (TARs) not encoded by annotated exons in the rice (Oryza. sativa) subspecies japonica and indica, respectively. The non-exonic TARs account for approximately two thirds of the total TARs detected by tiling arrays and represent transcripts likely conserved between japonica and indica. Transcription of 21,018 (83%) japonica non-exonic TARs was verified through expression profiling in 10 tissue types using a re-array in which annotated genes and TARs were each represented by five independent probes. Subsequent analyses indicate that about 80% of the japonica TARs that were not assigned to annotated exons can be assigned to various putatively functional or structural elements of the rice genome, including splice variants, uncharacterized portions of incompletely annotated genes, antisense transcripts, duplicated gene fragments, and potential non-coding RNAs. These results provide a systematic characterization of non-exonic transcripts in rice and thus expand the current view of the complexity and dynamics of the rice transcriptome. C1 [Li, Lei; Wang, Xiangfeng; Stolc, Viktor; Deng, Xing Wang] Yale Univ, Dept Mol Cellular & Dev Biol, New Haven, CT 06520 USA. [Wang, Xiangfeng; Deng, Wei; He, Hang] Natl Inst Biol Sci, Beijing, Peoples R China. [Wang, Xiangfeng] Peking Univ, Coll Life Sci, Peking Yale Joint Res Ctr Plant Mol Genet & Agrob, Beijing 100871, Peoples R China. [Sasidharan, Rajkumar; Korbel, Jan; Gerstein, Mark] Yale Univ, Dept Mol Biophys & Biochem, New Haven, CT USA. [Stolc, Viktor] NASA, Ames Res Ctr, Genome Res Facil, Moffett Field, CA 94035 USA. [Deng, Wei; He, Hang; Chen, Runsheng] Chinese Acad Sci, Inst Biophys, Bioinformat Lab, Beijing 100080, Peoples R China. [Chen, Xuewei; Ronald, Pamela] Univ Calif Davis, Dept Plant Pathol, Davis, CA 95616 USA. [Tongprasit, Waraporn] Eloret Corp, Sunnyvale, CA USA. RP Deng, XW (reprint author), Yale Univ, Dept Mol Cellular & Dev Biol, New Haven, CT 06520 USA. EM xingwang.deng@yale.edu RI Korbel, Jan/G-6470-2012; Deng, Wei/I-1280-2012 OI Korbel, Jan/0000-0002-2798-3794; FU NSF [DBI-0421675] FX This work was supported by a grant from the NSF Plant Genome Program (DBI-0421675). NR 48 TC 43 Z9 47 U1 0 U2 7 PU PUBLIC LIBRARY SCIENCE PI SAN FRANCISCO PA 185 BERRY ST, STE 1300, SAN FRANCISCO, CA 94107 USA SN 1932-6203 J9 PLOS ONE JI PLoS One PD MAR 14 PY 2007 VL 2 IS 3 AR e294 DI 10.1371/journal.pone.0000294 PG 13 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA V10DN UT WOS:000207444800017 PM 17372628 ER PT J AU Buermann, W Lintner, BR Koven, CD Angert, A Pinzon, JE Tucker, CJ Fung, IY AF Buermann, Wolfgang Lintner, Benjamin R. Koven, Charles D. Angert, Alon Pinzon, Jorge E. Tucker, Compton J. Fung, Inez Y. TI The changing carbon cycle at Mauna Loa Observatory SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article DE atmospheric circulation; atmospheric CO2 seasonal cycle; terrestrial carbon sinks; continental droughts ID ATMOSPHERIC CO2; SEASONAL CYCLE; DIOXIDE; DROUGHT; LAND; PRECIPITATION; LATITUDES; EXCHANGE; DATASET; FLUXES AB The amplitude of the CO2 seasonal cycle at the Mauna Loa Observatory (MLO) increased from the early 1970s to the early 1990s but decreased thereafter despite continued warming over northern continents. Because of its location relative to the large-scale atmospheric circulation, the MLO receives mainly Eurasian air masses in the northern hemisphere (NH) winter but relatively more North American air masses in NH summer. Consistent with this seasonal footprint, our findings indicate that the MLO amplitude registers North American net carbon uptake during the warm season and Eurasian net carbon release as well as anomalies in atmospheric circulation during the cold season. From the early 1970s to the early 1990s, our analysis was consistent with that of Keeling et al. [Keeling CID, Chin JFS, Whorf TP (1996) Nature 382:146-149], suggesting that the increase in the MILO CO2 amplitude is dominated by enhanced photosynthetic drawdown in North America and enhanced respiration in Eurasia. In contrast, the recent decline in the CO2 amplitude is attributed to reductions in carbon sequestration over North America associated with severe droughts from 1998 to 2003 and changes in atmospheric circulation leading to decreased influence of Eurasian air masses. With the return of rains to the U.S. in 2004, both the normalized difference vegetation index and the MLO amplitude sharply increased, suggesting a return of the North American carbon sink to more normal levels. These findings indicate that atmospheric CO2 measurements at remote sites can continue to play an important role in documenting changes in land carbon flux, including those related to widespread drought, which may continue to worsen as a result of global warming. C1 Univ Calif Los Angeles, Berkeley Atmospher Sci Ctr, Los Angeles, CA 90025 USA. Univ Calif Los Angeles, Dept Geog, Los Angeles, CA 90025 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Buermann, W (reprint author), Univ Calif Los Angeles, Inst Environm, Ctr Trop Res, Los Angeles, CA 90025 USA. EM buermann@ucla.edu; ifung@uclick.berkeley.edu RI Koven, Charles/N-8888-2014 OI Koven, Charles/0000-0002-3367-0065 NR 32 TC 50 Z9 52 U1 0 U2 34 PU NATL ACAD SCIENCES PI WASHINGTON PA 2101 CONSTITUTION AVE NW, WASHINGTON, DC 20418 USA SN 0027-8424 J9 P NATL ACAD SCI USA JI Proc. Natl. Acad. Sci. U. S. A. PD MAR 13 PY 2007 VL 104 IS 11 BP 4249 EP 4254 DI 10.1073/pnas.0611224104 PG 6 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 146ZH UT WOS:000244972700004 PM 17360510 ER PT J AU McHardy, I Lawson, A Newsam, A Marscher, AP Sokolov, AS Urry, CM Wehrle, AE AF McHardy, Ian Lawson, Anthony Newsam, Andrew Marscher, Alan P. Sokolov, Andrei S. Urry, C. Megan Wehrle, Ann E. TI Simultaneous X-ray and infrared variability in the quasar 3C273 - II. Confirmation of the correlation and X-ray lag SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE galaxies : active; quasars : individual : 3C273; X-rays : galaxies ID ACTIVE GALACTIC NUCLEI; RAPID NONTHERMAL FLARES; BASE-LINE ARRAY; 3C 273; BLACK-HOLE; XMM-NEWTON; HOT DUST; BLAZARS; RADIATION; LONG AB The X-ray emission from quasars, such as 3C273, is generally agreed to arise from Compton scattering of low-energy seed photons by relativistic electrons in a relativistic jet oriented close to the line of sight. However, there are a number of possible models for the origin of the seed photons. In Paper I (McHardy et al.), we showed that the X-ray and infrared (IR) variability from 3C273 was highly correlated in 1997, with the IR flux leading the X-rays by similar to 0.75 +/- 0.25 d. The strong correlation, and lag, supports the synchrotron self-Compton (SSC) model, where the seed photons are synchrotron photons from the jet itself. The previous correlation was based on one moderately well-sampled flare and another poorly sampled flare, so the possibility of chance correlated variability exists. Here, we report on further X-ray and IR observations of 3C273 which confirm the behaviour seen in Paper I. During a 2-week period of observations, we see a flare of amplitude similar to 25 per cent, lasting for similar to 5 d, showing a high correlation between IR and X-ray variations, with the X-rays lagging by similar to 1.45 +/- 0.15 d. These observations were not scheduled at any special time, implying that the same mechanism - almost certainly SSC - dominates the X-ray emission on most occasions and that the structure of the emission region is similar in most small flares. C1 Univ Southampton, Sch Phys & Astron, Southampton SO17 1BJ, Hants, England. Liverpool John Moores Univ, Astrophys Res Inst, Birkenhead CH41 1LD, Merseyside, England. Boston Univ, Inst Astrophys Res, Boston, MA 02215 USA. Yale Univ, Dept Phys, New Haven, CT 06520 USA. CALTECH, Pasadena, CA 91125 USA. Jet Prop Lab, IPAC, Pasadena, CA 91125 USA. RP McHardy, I (reprint author), Univ Southampton, Sch Phys & Astron, Southampton SO17 1BJ, Hants, England. EM imh@astro.soton.ac.uk RI Urry, Claudia/G-7381-2011 OI Urry, Claudia/0000-0002-0745-9792 NR 29 TC 13 Z9 13 U1 0 U2 2 PU BLACKWELL PUBLISHING PI OXFORD PA 9600 GARSINGTON RD, OXFORD OX4 2DQ, OXON, ENGLAND SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD MAR 11 PY 2007 VL 375 IS 4 BP 1521 EP 1527 DI 10.1111/j.1365-2966.2006.11420.x PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 139GE UT WOS:000244419500037 ER PT J AU Kent, GS Sage, KH Trepte, CR Wang, PH AF Kent, G. S. Sage, K. H. Trepte, C. R. Wang, P. -H. TI Stratospheric aerosol and gas experiment III cloud data product SO APPLIED OPTICS LA English DT Article ID HIGH-LEVEL CLOUDS; SAGE-II; TROPOSPHERIC AEROSOL; OCCULTATION DATA; ATMOSPHERIC AEROSOL; SIZE DISTRIBUTION; EXTINCTION; MODEL; DUST; SEPARATION AB The latest in a series of solar occultation satellite instruments, Stratospheric Aerosol and Gas Experiment (SAGE) III, was placed into orbit in December 2001, and data were obtained until March 2006. Measurements were made of the extinction attributable to aerosols and cloud at a number of wavelengths between 290 and 1550 nm. The analysis of data obtained by its predecessor, SAGE II, has shown that an intercomparison of such data at two or more wavelengths may be used to separate the effects of cloud and aerosol. This analysis has been done on a routine basis for many years using SAGE II data at 525 and 1020 nm and applied extensively to global studies of tropospheric cloud and aerosol. Here we describe the aerosol- cloud separation algorithm developed for use with the SAGE III data, which uses the extinction at 525, 1020, and 1550 nm. This algorithm is now being used to produce vertical profiles of cloud presence as a standard SAGE III data product. These profiles have a vertical resolution of 0.5 km and cover the altitude range from 6.0 to 30.0 km, and data are presently available from March 2002 onward. An outline is given of the development of this algorithm, the nature of the SAGE III data, and the algorithm performance. To maintain continuity with SAGE II cloud data, the relative performances of the SAGE II and SAGE III algorithms are also examined. An example of the application of the algorithm to SAGE III tropospheric data is shown and discussed. (c) 2007 Optical Society of America. C1 Sci & Technol Corp, Hampton, VA 23666 USA. Sci Applicat Int Corp, Hampton, VA USA. NASA, Langley Res Ctr, Hampton, VA 23665 USA. RP Kent, GS (reprint author), Sci & Technol Corp, Hampton, VA 23666 USA. EM g.s.kent@larc.nasa.gov NR 51 TC 1 Z9 2 U1 0 U2 1 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1559-128X EI 2155-3165 J9 APPL OPTICS JI Appl. Optics PD MAR 10 PY 2007 VL 46 IS 8 BP 1261 EP 1278 DI 10.1364/AO.46.001261 PG 18 WC Optics SC Optics GA 142GK UT WOS:000244637200012 PM 17318246 ER PT J AU Nandikotkur, G Jahoda, KM Hartman, RC Mukherjee, R Sreekumar, P Bottcher, M Sambruna, RM Swank, JH AF Nandikotkur, Giridhar Jahoda, Keith M. Hartman, R. C. Mukherjee, R. Sreekumar, P. Bottcher, M. Sambruna, R. M. Swank, Jean H. TI Does the blazar gamma-ray spectrum harden with increasing flux? Analysis of 9 years of EGRET data SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : active; methods : data analysis; methods : statistical; radiation mechanisms : nonthermal ID HIGH-ENERGY EMISSION; SELF-COMPTON MODELS; BL-LAC OBJECTS; X-RAY; MULTIWAVELENGTH OBSERVATIONS; EXPERIMENT TELESCOPE; MARKARIAN 501; PKS 0528+134; VARIABILITY; LACERTAE AB The Energetic Gamma-Ray Experiment Telescope (EGRET) on the Compton Gamma-Ray Observatory (CGRO) discovered gamma-ray emission from more than 67 blazars during its 9 yr lifetime. We conducted an exhaustive search of the EGRET archives and selected all the blazars that were observed multiple times and were bright enough to enable a spectral analysis using standard power-law models. The sample consists of 18 flat-spectrum radio quasars (FSRQs), 6 low-frequency peaked BL Lac objects (LBLs) and 2 high-frequency peaked BL Lac objects (HBLs). We do not detect any clear pattern in the variation of spectral index with flux. Some of the blazars do not show any statistical evidence for spectral variability. The spectrum hardens with increasing flux in a few cases. There is also evidence for a flux-hardness anticorrelation at low fluxes in five blazars. The well-observed blazars (3C 279, 3C 273, PKS 0528+134, PKS 1622-297, PKS 0208-512) do not show any overall trend in the long-term spectral dependence on flux, but the sample shows a mixture of hard and soft states. We observed a previously unreported spectral hysteresis at weekly timescales in all three FSRQs for which data from flares lasting for similar to(3-4) weeks were available. All three sources show a counterclockwise rotation, despite the widely different flux profiles. We analyze the observed spectral behavior in the context of various inverse Compton mechanisms believed to be responsible for emission in the EGRET energy range. Our analysis uses the EGRET skymaps that were regenerated to include the changes in performance during the mission. C1 Univ Maryland, Dept Phys, College Pk, MD 20742 USA. NASA, Goddard Space Flight Ctr, Explorat Universe Div, Greenbelt, MD 20771 USA. CUNY Bernard M Baruch Coll, Dept Phys & Astron, New York, NY 10010 USA. Columbia Univ, New York, NY USA. ISRO, Space Astron & Instrumentat Div, Satellite Ctr, Bangalore, Karnataka, India. Ohio Univ, Inst Astrophys, Dept Phys & Astron, Athens, OH 45701 USA. RP Nandikotkur, G (reprint author), Univ Maryland, Dept Phys, College Pk, MD 20742 USA. EM giridhar@milkyway.gsfc.nasa.gov RI Swank, Jean/F-2693-2012 NR 66 TC 43 Z9 44 U1 0 U2 4 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAR 10 PY 2007 VL 657 IS 2 BP 706 EP 724 DI 10.1086/510795 PN 1 PG 19 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 146IU UT WOS:000244928500006 ER PT J AU Yost, SA Swan, HF Rykoff, ES Aharonian, F Akerlof, CW Alday, A Ashley, MCB Barthelmy, S Burrows, D Depoy, DL Dufour, RJ Eastman, JD Forgey, RD Gehrels, N Gogus, E Guver, T Halpern, JP Hardin, LC Horns, D Kiziloglu, U Krimm, HA Lepine, S Liang, EP Marshall, JL Mckay, TA Mineo, T Mirabal, N Ozel, M Phillips, A Prieto, JL Quimby, RM Romano, P Rowell, G Rujopakarn, W Schaefer, BE Silverman, JM Siverd, R Skinner, M Smith, DA Smith, IA Tonnesen, S Troja, E Vestrand, WT Wheeler, JC Wren, J Yuan, F Zhang, B AF Yost, S. A. Swan, H. F. Rykoff, E. S. Aharonian, F. Akerlof, C. W. Alday, A. Ashley, M. C. B. Barthelmy, S. Burrows, D. Depoy, D. L. Dufour, R. J. Eastman, J. D. Forgey, R. D. Gehrels, N. Goegues, E. Guever, T. Halpern, J. P. Hardin, L. C. Horns, D. Kiziloglu, Ue. Krimm, H. A. Lepine, S. Liang, E. P. Marshall, J. L. McKay, T. A. Mineo, T. Mirabal, N. Oezel, M. Phillips, A. Prieto, J. L. Quimby, R. M. Romano, P. Rowell, G. Rujopakarn, W. Schaefer, B. E. Silverman, J. M. Siverd, R. Skinner, M. Smith, D. A. Smith, I. A. Tonnesen, S. Troja, E. Vestrand, W. T. Wheeler, J. C. Wren, J. Yuan, F. Zhang, B. TI Exploring broadband GRB behavior during gamma-ray emission SO ASTROPHYSICAL JOURNAL LA English DT Article DE gamma rays : bursts ID EARLY AFTERGLOW; BURST AFTERGLOWS; STAR-FORMATION; LIGHT-CURVE; PROMPT; RADIATION; MODEL; PHOTOMETRY; TELESCOPE; GALAXIES AB The robotic ROTSE-III telescope network detected prompt optical emission contemporaneous with the gamma-ray emission of Swift events GRB 051109A and GRB 051111. Both data sets have continuous coverage at high signal-to-noise levels from the prompt phase onward, and thus the early observations are readily compared to the Swift XRT and BAT high-energy detections. In both cases, the optical afterglow is established, declining steadily during the prompt emission. For GRB 051111, there is evidence of an excess optical component during the prompt emission. The component is consistent with the flux spectrally extrapolated from the gamma-rays, using the gamma-ray spectral index. A compilation of spectral information from previous prompt detections shows that such a component is unusual. The existence of two prompt optical components-one connected to the high-energy emission, the other to separate afterglow flux, as indicated in GRB 051111-is not compatible with a simple "external-external'' shock model for the GRB and its afterglow. C1 Univ Michigan, Ann Arbor, MI 48109 USA. Max Planck Inst Kernphys, D-69117 Heidelberg, Germany. Boeing LTS, AMOS Observ, Maui, HI USA. Univ New S Wales, Sch Phys, Dept Astrophys & Opt, Sydney, NSW, Australia. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Penn State Univ, Dept Astron, University Pk, PA 16802 USA. Ohio State Univ, Dept Astron, Columbus, OH 43210 USA. Rice Univ, Dept Phys & Astron, Houston, TX 77251 USA. Hardin Opt Co, Bandon, OR USA. Sabanci Univ, Istanbul, Turkey. Istanbul Univ, Dept Astron & Space Sci, Istanbul, Turkey. Columbia Univ, Columbia Astrophys Lab, New York, NY 10027 USA. Middle E Tech Univ, TR-06531 Ankara, Turkey. Univ Space Res Assoc, Columbia, MD USA. Amer Museum Nat Hist, Dept Astrophys, Div Phys Sci, New York, NY 10024 USA. INAF, Palermo, Italy. Canakkale Onsekiz Mart Univ, Canakkale, Turkey. Univ Texas, Dept Astron, Austin, TX 78712 USA. Osserv Astron Brera, Merate, Italy. Louisiana State Univ, Dept Phys & Astron, Baton Rouge, LA 70803 USA. Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA. Guilford Coll, Greensboro, NC 27410 USA. Los Alamos Natl Lab, Los Alamos, NM USA. Univ Nevada, Dept Phys, Las Vegas, NV 89154 USA. RP Yost, SA (reprint author), Univ Michigan, Ann Arbor, MI 48109 USA. EM sayost@umich.edu; hswan@umich.edu; erykoff@umich.edu; felix.aharonian@mpi-hd.mpg.de; akerlof@umich.edu; andrew.alday-iii@boeing.com; mcba@phys.unsw.edu.au; scott@lheamail.gsfc.nasa.gov; dburrows@astro.psu.edu; depoy@astronomy.ohio-state.edu; rjd@rice.edu; jdeast@astronomy.ohio-state.edu; bob@hardinoptical.com; gehrels@gsfc.nasa.gov; ersing@sabanciuniv.edu; tolga@istanbul.edu.tr; jules@astro.columbia.edu; larry@hardinoptical.com; horns@mpi-hd.mpg.de; umk@astroa.physics.metu.edu.tr; krimm@milkyway.gsfc.nasa.gov; lepine@amnh.org; liang@spacibm.rice.edu; marshall@astronomy.ohio-state.edu; tamckay@umich.edu; teresa.mineo@ifc.inaf.it; mirabal@astro.columbia.edu; m.e.ozel@comu.edu.tr; a.phillips@unsw.edu.au; prieto@astronomy.ohio-state.edu; quimby@astro.as.utexas.edu; patrizia.romano@brera.inaf.it; rowell@mpi-hd.mpg.de; wiphu@umich.edu; schaefer@lsu.edu; JSilverman@astro.berkeley.edu; siverd@astronomy.ohio-state.edu; mark.a.skinner@boeing.com; donaldas@umich.edu; ian@spacibm.rice.edu; stonnes@astro.columbia.edu; nora@ifc.inaf.it; vestrand@lanl.gov; wheel@astro.as.utexas.edu; jwren@nis.lanl.gov; yuanfang@umich.edu; bzhang@physics.unlv.edu RI Guver, Tolga/C-1408-2011; Horns, Dieter/C-9727-2011; Barthelmy, Scott/D-2943-2012; Gehrels, Neil/D-2971-2012; Rujopakarn, Wiphu/E-7849-2012; McKay, Timothy/C-1501-2009; Guver, Tolga/B-1039-2014 OI McKay, Timothy/0000-0001-9036-6150; Guver, Tolga/0000-0002-3531-9842 NR 51 TC 47 Z9 47 U1 0 U2 8 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAR 10 PY 2007 VL 657 IS 2 BP 925 EP 941 DI 10.1086/510896 PN 1 PG 17 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 146IU UT WOS:000244928500021 ER PT J AU Patel, SK Zurita, J Del Santo, M Finger, M Kouveliotou, C Eichler, D Gogus, E Ubertini, P Walter, R Woods, P Wilson, CA Wachter, S Bazzano, A AF Patel, S. K. Zurita, J. Del Santo, M. Finger, M. Kouveliotou, C. Eichler, D. Goegues, E. Ubertini, P. Walter, R. Woods, P. Wilson, C. A. Wachter, S. Bazzano, A. TI A possible magnetar nature for IGR J16358-4726 SO ASTROPHYSICAL JOURNAL LA English DT Article DE pulsars : individual (IGR J16358-4726) ID X-RAY SOURCES; PULSAR GLITCHES; SPECTRAL-ANALYSIS; NEUTRON STARS; ACCRETION; MODELS AB We present detailed spectral and timing analysis of the hard X-ray transient IGR J16358-4726 using multisatellite archival observations. A study of the source flux time history over 6 yr suggests that lower luminosity transient outbursts can be occurring in intervals of at most 1 yr. Joint spectral fits of the higher luminosity outburst using simultaneous Chandra ACIS and INTEGRAL ISGRI data reveal a spectrum well described by an absorbed power-law model with a high-energy cutoff plus an Fe line. We detected the 1.6 hr pulsations initially reported using Chandra ACIS also in the INTEGRAL ISGRI light curve and in subsequent XMM-Newton observations. Using the INTEGRAL data, we identified a spin-up of 94 s ((P) over dot = 1.6 x 10(-4)), which strongly points to a neutron star nature for IGR J16358-4726. Assuming that the spin-up is due to disk accretion, we estimate that the source magnetic field ranges between 10(13) and 10(15) G, depending on its distance, possibly supporting a magnetar nature for IGR J16358-4726. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. Univ Space Res Assoc, Huntsville, AL USA. INTEGRAL Sci Data Ctr, Versoix, Switzerland. Observ Geneva, CH-1290 Sauverny, Switzerland. INAF, Ist Astrofis Spaziale & Fis Cosm Roma, Rome, Italy. Ben Gurion Univ Negev, Dept Phys, IL-84105 Beer Sheva, Israel. Sabanci Univ, FENS, Istanbul, Turkey. CALTECH, Spitzer Sci Ctr, Pasadena, CA 91125 USA. RP Patel, SK (reprint author), NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. OI Del Santo, Melania/0000-0002-1793-1050; Bazzano, Angela/0000-0002-2017-4396 NR 39 TC 16 Z9 16 U1 0 U2 3 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAR 10 PY 2007 VL 657 IS 2 BP 994 EP 1003 DI 10.1086/510374 PN 1 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 146IU UT WOS:000244928500025 ER PT J AU Weisskopf, MC Wu, KW Trimble, V O'Dell, SL Elsner, RF Zavlin, VE Kouveliotou, C AF Weisskopf, Martin C. Wu, Kinwah Trimble, Virginia O'Dell, Stephen L. Elsner, Ronald F. Zavlin, Vyacheslav E. Kouveliotou, Chryssa TI A Chandra search for coronal X-rays from the cool white dwarf GD 356 SO ASTROPHYSICAL JOURNAL LA English DT Article DE methods : statistical; radiation mechanisms : thermal; stars : coronae; white dwarfs; X-rays : individual (GD 356) ID MAGNETIC-FIELDS; DA; RADIATION; STARS; ROSAT; DB; OSCILLATIONS; ATMOSPHERES; GENERATION; ENVELOPES AB We report observations with the Chandra X-ray Observatory of the single, cool, magnetic white dwarf GD 356. For consistent comparison with other X-ray observations of single white dwarfs, we also re-analyzed archival ROSAT data for GD356 (GJ 1205), G99-47 (GR290 = V1201 Ori), GD90, G195-19 (EG250 = GJ339.1), and WD2316+123, and archival Chandra data for LHS 1038 (GJ 1004) and GD 358 (V777 Her). Our Chandra observation detected no X-rays from GD 356, setting the most restrictive upper limit to the X-ray luminosity from any cool white dwarf: L(X) < 6.0; 10(25) ergs s(-1), at 99.7% confidence, for a 1 keV thermal bremsstrahlung spectrum. The corresponding limit to the electron density is n(0) < 4.4 x 10(11) cm(-3). Our re-analysis of the archival data confirmed the nondetections reported by the original investigators. We discuss the implications of our and prior observations for models of coronal emission from white dwarfs. For magnetic white dwarfs, we emphasize the more stringent constraints imposed by cyclotron radiation. In addition, we describe (in an Appendix) a statistical methodology for detecting a source and for constraining the strength of a source, which applies even when the number of source or background events is small. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. UCL, Mullard Space Sci Lab, Holmbury, England. Univ Calif Irvine, Dept Phys & Astron, Irvine, CA USA. Las Cumbres Observ, Goleta, CA USA. RP Weisskopf, MC (reprint author), NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. EM martin@smoker.msfc.nasa.gov OI O'Dell, Stephen/0000-0002-1868-8056 NR 44 TC 30 Z9 30 U1 0 U2 4 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAR 10 PY 2007 VL 657 IS 2 BP 1026 EP 1036 DI 10.1086/510776 PN 1 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 146IU UT WOS:000244928500028 ER PT J AU Reiner, MJ Krucker, S Gray, DE Dougherty, BL Kaiser, ML Bougeret, JL AF Reiner, M. J. Krucker, S. Gray, D. E. Dougherty, B. L. Kaiser, M. L. Bougeret, J. -L. TI Radio and white-light coronal signatures associated with the RHESSI hard X-ray event of 2002 July 23 SO ASTROPHYSICAL JOURNAL LA English DT Article DE Sun : activity; Sun : corona; Sun : flares; Sun : radio radiation; Sun : X-rays, gamma rays; solar-terrestrial relations ID SOLAR CORONA; MASS EJECTIONS; SHOCK-WAVE; II BURSTS; INTERPLANETARY SHOCKS; ENERGETIC PARTICLES; ELECTRON-DENSITY; ORIGIN; EMISSION; FLARE AB Simultaneous radio, white-light, and hard X-ray (HXR) observations for the 2002 July 23 gamma-ray flare event are used to establish the relationship of a complex type III-like burst to the corresponding coronal mass ejection (CME) and the coronal electron acceleration signatures observed in the decimeter/microwave (dm-cm) emissions and X-rays. We find that the onset of the type III-like emissions for this event is coincident with the impulsive RHESSI HXR event, the dm-cm radio emissions and with the linearly extrapolated liftoff time of the CME. The overall intensity-time characteristics of the complex type III-like burst resembles that of both the dm-cm flux and the HXR light curve that correspond to an electron acceleration event deep in the corona. Furthermore, the complex radiation characteristics of the type III-like emissions are found to be directly related to the CME kinematics, which is directly related to the frequency drift of the associated low-frequency (kilometric) type II emissions. The frequency-drift characteristics of the high-frequency (metric) type II emissions observed for this event, on the other hand, are not clearly related to the kilometric type II emissions and therefore to the observed CME height-time characteristics, indicating that these emissions may correspond to an independent coronal shock wave. C1 Catholic Univ Amer, Washington, DC 20064 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. New Jersey Inst Technol, Ctr Solar Terr Res, Newark, NJ 07102 USA. Los Alamos Natl Lab, Los Alamos, NM USA. NASA, Goddard Space Flight Ctr, Space Weather Lab, Greenbelt, MD 20771 USA. Observ Paris, LESIA, Meudon, France. RP Reiner, MJ (reprint author), Catholic Univ Amer, Washington, DC 20064 USA. OI Gary, Dale/0000-0003-2520-8396 NR 54 TC 13 Z9 13 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAR 10 PY 2007 VL 657 IS 2 BP 1107 EP 1116 DI 10.1086/510827 PN 1 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 146IU UT WOS:000244928500036 ER PT J AU Elias, NM Harwit, M Leisawitz, D Rinehart, SA AF Elias, Nicholas M., II Harwit, Martin Leisawitz, David Rinehart, Stephen A. TI The mathematics of double-Fourier interferometers SO ASTROPHYSICAL JOURNAL LA English DT Article DE methods : analytical; methods : data analysis; techniques : high angular resolution; techniques : image processing; techniques : interferometric; techniques : spectroscopic ID TERRESTRIAL-PLANET-FINDER; OPTICAL INTERFEROMETER; POLARIMETRY; STARS AB Recent studies, which are the impetus for this paper, have investigated the possibility of astronomical wide-field double-Fourier interferometry at submillimeter and midinfrared wavelengths. Double-Fourier interferometry combines Michelson interferometry and Fourier transform spectroscopy. At the present time, it is the only technique that promises simultaneous high spatial and spectral resolution. First, we derive the near-general output response for wide-field double-Fourier interferometers using the Jones and Mueller calculi. We employ a "systems'' approach, expressing the instrument behavior in terms of matrix electric field and intensity impulse responses (point-spread functions) between the sky and the focal plane. This approach is helpful for integrated modeling, Monte Carlo simulations, and developing instrument requirements from science goals. Second, we furnish three wavenumber-dependent observables visibilities, squared visibility magnitudes, and dirty/processed images-plus their (co)variances in the photon-rich regime. Third, to obtain a basic understanding of the mathematics in this paper, the output responses for perfect, phase-aberrated, and polarization-mismatched optics are produced. Last, we present ideas for future research in wide-field double-Fourier interferometers, such as SPIRIT and SPECS. C1 Ball Aerosp & Technol Corp, Boulder, CO USA. Cornell Univ, Dept Astron, Ithaca, NY 14853 USA. NASA, Goddard Space Flight Ctr, Observat Cosmol Observ, Greenbelt, MD 20771 USA. RP Elias, NM (reprint author), Univ Heidelberg, Zentrum Astron, Landessternwarte, Heidelberg, Germany. EM n.elias@lsw.uni-heidelberg.de NR 23 TC 15 Z9 15 U1 0 U2 5 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAR 10 PY 2007 VL 657 IS 2 BP 1178 EP 1200 DI 10.1086/510878 PN 1 PG 23 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 146IU UT WOS:000244928500044 ER PT J AU Foschini, L Ghisellini, G Tavecchio, F Treves, A Maraschi, L Gliozzi, M Raiteri, CM Villata, M Pian, E Tagliaferri, G Tosti, G Sambruna, RM Malaguti, G Di Cocco, G Giommi, P AF Foschini, L. Ghisellini, G. Tavecchio, F. Treves, A. Maraschi, L. Gliozzi, M. Raiteri, C. M. Villata, M. Pian, E. Tagliaferri, G. Tosti, G. Sambruna, R. M. Malaguti, G. Di Cocco, G. Giommi, P. TI X-ray/UV/optical follow-up of the blazar PKS 2155-304 after the giant TeV flares of 2006 July SO ASTROPHYSICAL JOURNAL LA English DT Article DE BL Lacertae objects : general; BL Lacertae objects : individual (PKS 2155-304) ID LACERTAE OBJECT PKS-2155-304; ACTIVE GALACTIC NUCLEI; ENERGY GAMMA-RAYS; SPECTRAL EVOLUTION; TELESCOPE; BEPPOSAX; MARKARIAN-501; MISSION; HESS; JET AB We present all the publicly available data, from optical/UV wavelengths (UVOT) to X-rays (XRT, BAT), obtained from Swift observations of the blazar PKS 2155-304, performed in response to the rapid alert sent out after the strong TeV activity (up to 17 crab flux level at E > 200 GeV) at the end of 2006 July. The X-ray flux increased by a factor of 5 in the 0.3-10 keV energy band and by a factor of 1.5 at optical/UV wavelengths, with roughly 1 day of delay. The comparison of the spectral energy distribution built with data quasi-simultaneous to the TeV detections shows an increase of the overall normalization with respect to archival data but only a small shift of the frequency of the synchrotron peak that remains consistent with the values reported in past observations when the TeV activity was much weaker. C1 Ist Astrofis Spaziale & Fis Cosm, INAF, Bologna, Italy. Osserv Astron Brera, INAF, Milan, Italy. Univ Insubria, Dipartimento Sci, Como, Italy. George Mason Univ, Sch Computat Sci, Dept Phys & Astron, Fairfax, VA 22030 USA. Osserv Astron Torino, INAF, I-10025 Pino Torinese, Italy. Osserv Astron Trieste, INAF, I-34131 Trieste, Italy. Univ Perugia, Osservatorio Astron, I-06100 Perugia, Italy. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. ASI Sci Data Ctr, Frascati, Italy. RP Foschini, L (reprint author), Ist Astrofis Spaziale & Fis Cosm, INAF, Bologna, Italy. EM foschini@iasfbo.inaf.it RI Foschini, Luigi/H-3833-2012; Tosti, Gino/E-9976-2013; OI Pian, Elena/0000-0001-8646-4858; Foschini, Luigi/0000-0001-8678-0324; Raiteri, Claudia Maria/0000-0003-1784-2784; Tagliaferri, Gianpiero/0000-0003-0121-0723 NR 28 TC 42 Z9 42 U1 0 U2 4 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAR 10 PY 2007 VL 657 IS 2 BP L81 EP L84 DI 10.1086/513271 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 146IX UT WOS:000244928800005 ER PT J AU Eytani, Y Havelund, K Stoller, SD Ur, S AF Eytani, Yaniv Havelund, Klaus Stoller, Scott D. Ur, Shmuel TI Towards a framework and a benchmark for testing tools for multi-threaded programs SO CONCURRENCY AND COMPUTATION-PRACTICE & EXPERIENCE LA English DT Article; Proceedings Paper CT Parallel and Distributed Systems - Testing and Debugging Conference CY NOV, 2005 CL Haifa, ISRAEL DE testing; concurrency; benchmark; multi-threaded AB Multi-threaded code is becoming very common, both on the server side, and very recently for personal computers as well. Consequently, looking for intermittent bugs is a problem that is receiving more and more attention. As there is no silver bullet, research focuses on a variety of partial solutions. We outline a road map for combining the research within the different disciplines of testing multi-threaded programs and for evaluating the quality of this research. We have three main goals. First, to create a benchmark that can be used to evaluate different solutions. Second, to create a framework with open application programming interfaces that enables the combination of techniques in the multi-threading domain. Third, to create a focus for the research in this area around which a community of people who try to solve similar problems with different techniques can congregate. We have started creating such a benchmark and describe the lessons learned in the process. The framework will enable technology developers, for example, developers of race detection algorithms, to concentrate on their components and use other ready made components (e.g. an instrumentor) to create a testing solution. Copyright (c) 2006 John Wiley & Sons, Ltd. C1 Univ Haifa, Dept Comp Sci, IL-31999 Haifa, Israel. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. SUNY Stony Brook, Dept Comp Sci, Stony Brook, NY 11794 USA. IBM Corp, Haifa Res Lab, IL-31905 Haifa, Israel. RP Ur, S (reprint author), IBM Corp, Haifa Res Lab, Haifa Univ Campus, IL-31905 Haifa, Israel. EM ur@il.ibm.com NR 57 TC 15 Z9 15 U1 0 U2 1 PU JOHN WILEY & SONS LTD PI CHICHESTER PA THE ATRIUM, SOUTHERN GATE, CHICHESTER PO19 8SQ, W SUSSEX, ENGLAND SN 1532-0626 J9 CONCURR COMP-PRACT E JI Concurr. Comput.-Pract. Exp. PD MAR 10 PY 2007 VL 19 IS 3 BP 267 EP 279 DI 10.1002/cpe.1068 PG 13 WC Computer Science, Software Engineering; Computer Science, Theory & Methods SC Computer Science GA 143KG UT WOS:000244719500002 ER PT J AU Li, T She, CY Liu, HL Montgomery, MT AF Li, Tao She, C. -Y. Liu, Han-Li Montgomery, Michael T. TI Evidence of a gravity wave breaking event and the estimation of the wave characteristics from sodium lidar observation over Fort Collins, CO (41 degrees N, 105 degrees W) SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID MESOPAUSE REGION; INVERSION LAYER; TEMPERATURE; MESOSPHERE; TURBULENCE; BREAKDOWN AB On the night of December 3rd, 2004 (UT day 338), we observed a significant acceleration of horizontal wind near 100 km between 0900 and 0915 UT accompanied by a temperature cooling at the same altitude and warming below it. The Lomb spectrum analysis of the raw dataset revealed that a gravity wave with 1.5 hr period was significant between 0500 and 0900 UT, but blurred after 0900 UT, suggesting the transfer of wave energy and momentum from wave field to mean flow. Most likely, this observed phenomenon is due to the breaking of an upward propagating gravity wave with an apparent period of similar to 1.5 hr. Using linear saturation theory and assuming a monochromatic wave packet, we estimated the characteristics of breaking gravity wave, eddy diffusion coefficient, and a simple relation between Prandtl number and turbulence localization measure when the wave is breaking, from the experimentally determined heating rate, horizontal wind acceleration, and background temperature and winds. C1 Colorado State Univ, Dept Phys, Ft Collins, CO 80523 USA. Natl Ctr Atmospher Res, High Altitude Observ, Boulder, CO 80307 USA. USN, Postgrad Sch, Dept Meteorol, Monterey, CA 93943 USA. NOAA, Hurricane Res Div, Miami, FL USA. RP Li, T (reprint author), CALTECH, Jet Propuls Lab, Table Mt Facil, 24490 Table Mt Rd,POB 367, Wrightwood, CA 92397 USA. EM taoli@tmf.jpl.nasa.gov RI Liu, Han-Li/A-9549-2008; Li, Tao/J-8950-2014 OI Liu, Han-Li/0000-0002-6370-0704; Li, Tao/0000-0002-5100-4429 NR 17 TC 17 Z9 19 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 EI 1944-8007 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD MAR 10 PY 2007 VL 34 IS 5 AR L05815 DI 10.1029/2006GL028988 PG 5 WC Geosciences, Multidisciplinary SC Geology GA 145XB UT WOS:000244898000006 ER PT J AU Gautam, R Hsu, NC Kafatos, M Tsay, SC AF Gautam, Ritesh Hsu, N. Christina Kafatos, Menas Tsay, Si-Chee TI Influences of winter haze on fog/low cloud over the Indo-Gangetic plains SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID SULFUR-DIOXIDE EMISSIONS; ATMOSPHERIC BROWN CLOUDS; AEROSOL OPTICAL DEPTH; DUST STORMS; BASIN; FOG; PRECIPITATION; VARIABILITY; COMBUSTION; WIDESPREAD AB The aerosol loading in south Asia has increased considerably because of the growing population, urbanization, and industrialization in recent years. To understand the effects of aerosols on cloud properties in this region, we have analyzed an extensive collection of aerosol and cloud properties, obtained from the Moderate resolution Imaging Spectroradiometer ( MODIS) data, over the Indian subcontinent during winter 2000-2006. During these winter months, the Indo-Gangetic (IG) plains, in the northern part of India, are subjected to dense haze and fog on the basis of MODIS climatology of aerosol optical depth and cloud properties ( cloud effective radius, cloud top pressure, and cloud fraction), respectively. We derive a fog/low-cloud detection scheme from MODIS level 2 data to generate distribution of fog/low cloud on a daily basis for December-January 2000-2006. Interactions between winter haze and fog/low cloud over the IG plains were analyzed by minimizing the effect of dynamical processes associated with fog formation. On the basis of the interannual variability of meteorological parameters, winter 2004-2005 was associated with favorable conditions for fog formation in terms of comparable values of relative humidity with respect to previous years. However, significantly lower fog occurrences were found in winter 2004-2005 over the IG plains from MODIS and ground observations, while higher aerosol loading was observed in 2004-2005 compared to previous years. Thus the role of higher aerosol loading in 2004-2005 was investigated, combined with the high concentration of black carbon ( BC) aerosols over the IG plains, indicated by aerosol transport model, suggesting that the BC aerosols may have significant impact on the fog/low-cloud formation over the IG plains and hence less fog in winter 2004-2005. C1 George Mason Univ, Ctr Earth Observing & Space Res, Fairfax, VA 22030 USA. NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. RP Gautam, R (reprint author), George Mason Univ, Ctr Earth Observing & Space Res, Fairfax, VA 22030 USA. EM rgautam@gmu.edu RI Gautam, Ritesh/E-9776-2010; Hsu, N. Christina/H-3420-2013; Tsay, Si-Chee/J-1147-2014 OI Gautam, Ritesh/0000-0002-2177-9346; NR 33 TC 73 Z9 75 U1 1 U2 27 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAR 9 PY 2007 VL 112 IS D5 AR D05207 DI 10.1029/2005JD007036 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 145XM UT WOS:000244899100001 ER PT J AU Tsurutani, BT Lakhina, GS Verkhoglyadova, OP Echer, E Guarnieri, FL AF Tsurutani, Bruce T. Lakhina, Gurbax S. Verkhoglyadova, Olga P. Echer, Ezequiel Guarnieri, Fernando L. TI Comment on "Comment on the abundances of rotational and tangential discontinuities in the solar wind'' by M. Neugebauer SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Editorial Material ID NONLINEAR ALFVEN WAVES; MAGNETIC HOLES; DIRECTIONAL DISCONTINUITIES; INTERPLANETARY SPACE; ULYSSES OBSERVATIONS; PONDEROMOTIVE FORCE; FLUID MODELS; DECREASES; EVOLUTION; CLUSTER C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. Indian Inst Geomagnetism, Navi Mumbai, Bombay, Maharashtra, India. Univ Calif Riverside, Inst Geophys & Planetary Phys, Riverside, CA 92521 USA. Natl Inst Space Res, Sao Jose Dos Campos, Brazil. Univ Vale Paraiba, Inst Pesquisa & Desenvolvimento, Sao Jose Dos Campos, Brazil. RP Tsurutani, BT (reprint author), CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RI Lakhina, Gurbax /C-9295-2012; OI Lakhina, Gurbax /0000-0002-8956-486X; Verkhoglyadova, Olga/0000-0002-9295-9539 NR 29 TC 10 Z9 11 U1 1 U2 5 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD MAR 9 PY 2007 VL 112 IS A3 AR A03101 DI 10.1029/2006JA011973 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 145XZ UT WOS:000244900400002 ER PT J AU Noel, V Winker, DM Garrett, TJ McGill, M AF Noel, V. Winker, D. M. Garrett, T. J. McGill, M. TI Extinction coefficients retrieved in deep tropical ice clouds from lidar observations using a CALIPSO-like algorithm compared to in-situ measurements from the cloud integrating nephelometer during CRYSTAL-FACE SO ATMOSPHERIC CHEMISTRY AND PHYSICS LA English DT Article ID CIRRUS CLOUDS; OPTICAL-PROPERTIES; RATIO; LAND AB @This paper presents a comparison of lidar ratios and volume extinction coefficients in tropical ice clouds, retrieved using observations from two instruments: the 532-nm Cloud Physics Lidar (CPL), and the in-situ Cloud Integrating Nephelometer (CIN) probe. Both instruments were mounted on airborne platforms during the CRYSTAL-FACE campaign and took measurements up to 17 km. Coincident observations from two cases of ice clouds located on top of deep convective systems are compared. First, lidar ratios are retrieved from CPL observations of attenuated backscatter, using a retrieval algorithm for opaque cloud similar to one used in the recently launched CALIPSO mission, and compared to results from the regular CPL algorithm. These lidar ratios are used to retrieve extinction coefficient profiles, which are compared to actual observations from the CIN in-situ probe, putting the emphasis on their vertical variability. When observations coincide, retrievals from both instruments are very similar, in the limits of colocation. Differences are generally variations around the average profiles, and general trends on larger spatial scales are well reproduced. The two instruments agree well, with an average difference of less than 11% on optical depth retrievals. Results suggest the CALIPSO Deep Convection algorithm can be trusted to deliver realistic estimates of the lidar ratio, leading to good retrievals of extinction coefficients. C1 Meteorol Dynam Lab, Palaiseau, France. NASA, Langley Res Ctr, Hampton, VA 23665 USA. Univ Utah, Salt Lake City, UT 84112 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Noel, V (reprint author), Meteorol Dynam Lab, Palaiseau, France. EM vincent.noel@lmd.polytechnique.fr RI McGill, Matthew/D-8176-2012; Noel, Vincent/C-3702-2013 OI Noel, Vincent/0000-0001-9494-0340 NR 27 TC 11 Z9 11 U1 1 U2 3 PU EUROPEAN GEOSCIENCES UNION PI KATLENBURG-LINDAU PA MAX-PLANCK-STR 13, 37191 KATLENBURG-LINDAU, GERMANY SN 1680-7316 J9 ATMOS CHEM PHYS JI Atmos. Chem. Phys. PD MAR 8 PY 2007 VL 7 BP 1415 EP 1422 PG 8 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 145IH UT WOS:000244858000001 ER PT J AU Thomason, LW Poole, LR Randall, CE AF Thomason, L. W. Poole, L. R. Randall, C. E. TI SAGE III aerosol extinction validation in the arctic winter: comparisons with SAGE II and POAM III SO ATMOSPHERIC CHEMISTRY AND PHYSICS LA English DT Article ID POLAR STRATOSPHERIC CLOUDS; SAM-II; ALGORITHM; CLIMATOLOGY; VORTEX AB The use of SAGE III multiwavelength aerosol extinction coefficient measurements to infer PSC type is contingent on the robustness of both the extinction magnitude and its spectral variation. Past validation with SAGE II and other similar measurements has shown that the SAGE III extinction coefficient measurements are reliable though the comparisons have been greatly weighted toward measurements made at mid-latitudes. Some aerosol comparisons made in the Arctic winter as a part of SOLVE II suggested that SAGE III values, particularly at longer wavelengths, are too small with the implication that both the magnitude and the wavelength dependence are not reliable. Comparisons with POAM III have also suggested a similar discrepancy. Herein, we use SAGE II data as a common standard for comparison of SAGE III and POAM III measurements in the Arctic winters of 2002/2003 through 2004/2005. During the winter, SAGE II measurements are made infrequently at the same latitudes as these instruments. We have mitigated this problem through the use of potential vorticity as a spatial coordinate and thus greatly increased of the number of coincident events. We find that SAGE II and III extinction coefficient measurements show a high degree of compatibility at both 1020 nm and 450 nm except a 10-20% bias at both wavelengths. In addition, the 452 to 1020 nm extinction ratio shows a consistent bias of similar to 30% throughout the lower stratosphere. We also find that SAGE II and POAM III are on average consistent though the comparisons show a much higher variability and larger bias than SAGE II/III comparisons. In addition, we find that SAGE II and POAM III data sets are not well correlated at and below 18 km. Overall, we find both the extinction values and the spectral dependence from SAGE III are robust and we find no evidence of a significant defect within the Arctic vortex. C1 NASA, Langley Res Ctr, Hampton, VA 23665 USA. Sci Applicat Int Corp, Hampton, VA USA. Univ Colorado, Boulder, CO 80309 USA. RP Thomason, LW (reprint author), NASA, Langley Res Ctr, Hampton, VA 23665 USA. EM l.w.thomason@larc.nasa.gov RI Randall, Cora/L-8760-2014; OI Randall, Cora/0000-0002-4313-4397; Thomason, Larry/0000-0002-1902-0840 NR 16 TC 10 Z9 11 U1 0 U2 0 PU COPERNICUS PUBLICATIONS PI KATHLENBURG-LINDAU PA MAX-PLANCK-STR 13, KATHLENBURG-LINDAU, 37191, GERMANY SN 1680-7316 J9 ATMOS CHEM PHYS JI Atmos. Chem. Phys. PD MAR 8 PY 2007 VL 7 BP 1423 EP 1433 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 145IH UT WOS:000244858000002 ER PT J AU Romanou, A Liepert, B Schmidt, GA Rossow, WB Ruedy, RA Zhang, Y AF Romanou, A. Liepert, B. Schmidt, G. A. Rossow, W. B. Ruedy, R. A. Zhang, Y. TI 20th century changes in surface solar irradiance in simulations and observations SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID RADIATION; CLIMATE; AEROSOLS; ATMOSPHERE; CYCLE AB The amount of solar irradiance reaching the surface is a key parameter in the hydrological and energy cycles of the Earth's climate. We analyze 20th Century simulations using nine state-of-the-art climate models and show that all models estimate a global annual mean reduction in downward surface solar radiation of 1-4 W/m(2) at the same time that the globe warms by 0.4-0.7 degrees C. In single forcing simulations using the GISS-ER model, this "global dimming" signal is shown to be predominantly related to aerosol effects. In the global mean sense the surface adjusts to changes in downward solar flux instantaneously by reducing the upward fluxes of longwave, latent and sensible heat. Adding increased greenhouse gas forcing traps outgoing longwave radiation in the atmosphere and surface which results in net heating ( although reduced) that is consistent with global warming over the 20th Century. Over the 1984-2000 period, individual model simulations show widely disparate results, mostly related to cloud changes associated with tropical Pacific variations, similar to the changes inferred from the satellite data analysis. This suggests that this time period is not sufficient to determine longer term trends. C1 Columbia Univ, Dept Appl Math & Phys, New York, NY 10025 USA. Columbia Univ, Lamont Doherty Earth Observ, Palisades, NY 10964 USA. NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Sigma Space Partners, New York, NY 10025 USA. RP Romanou, A (reprint author), Columbia Univ, Dept Appl Math & Phys, Armstrong Hall, New York, NY 10025 USA. EM ar2235@columbia.edu RI Schmidt, Gavin/D-4427-2012; Rossow, William/F-3138-2015 OI Schmidt, Gavin/0000-0002-2258-0486; NR 17 TC 48 Z9 51 U1 2 U2 9 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 EI 1944-8007 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD MAR 8 PY 2007 VL 34 IS 5 AR L05713 DI 10.1029/2006GL028356 PG 5 WC Geosciences, Multidisciplinary SC Geology GA 145WX UT WOS:000244897600003 ER PT J AU Tucker, DL Ott, CM Huff, S Fofanov, Y Pierson, DL Willson, RC Fox, GE AF Tucker, Don L. Ott, C. Mark Huff, Stephen Fofanov, Yuriy Pierson, Duane L. Willson, Richard C. Fox, George E. TI Characterization of Escherichia coli MG1655 grown in a low-shear modeled microgravity environment SO BMC MICROBIOLOGY LA English DT Article ID GENE-EXPRESSION; STRESS-RESPONSE; SIMULATED MICROGRAVITY; FUNCTIONAL GENOMICS; CARRIER PROTEIN; K-12; TYPHIMURIUM; REGULON; SYSTEM; CARBOXYLASE AB Background: Extra-cellular shear force is an important environmental parameter that is significant both medically and in the space environment. Escherichia coli cells grown in a low-shear modeled microgravity ( LSMMG) environment produced in a high aspect rotating vessel ( HARV) were subjected to transcriptional and physiological analysis. Results: Aerobic LSMMG cultures were grown in rich ( LB) and minimal ( MOPS + glucose) medium with a normal gravity vector HARV control. Reproducible changes in transcription were seen, but no specific LSMMG responsive genes were identified. Instead, absence of shear and a randomized gravity vector appears to cause local extra-cellular environmental changes, which elicit reproducible cellular responses. In minimal media, the majority of the significantly up- or down-regulated genes of known function were associated with the cell envelope. In rich medium, most LSMMG down-regulated genes were involved in translation. No observable changes in post-culture stress responses and antibiotic sensitivity were seen in cells immediately after exposure to LSMMG. Comparison with earlier studies of Salmonella enterica serovar Typhimurium conducted under similar growth conditions, revealed essentially no similarity in the genes that were significantly up- or down-regulated. Conclusion: Comparison of these results to previous studies suggests that different organisms may dramatically differ in their responses to medically significant low-shear and space environments. Depending on their specific response, some organisms, such as Salmonella, may become preadapted in a manner that predisposes them to increased virulence. C1 Univ Houston, Dept Biol & Biochem, Houston, TX 77204 USA. NASA, Lyndon B Johnson Space Ctr, Habitabil & Environm Factors Off, Houston, TX 77058 USA. Univ Houston, Dept Comp Sci, Houston, TX 77204 USA. Univ Houston, Dept Chem Engn, Houston, TX 77204 USA. RP Fox, GE (reprint author), Univ Houston, Dept Biol & Biochem, 369 Sci & Res Bldg,2, Houston, TX 77204 USA. EM dtucker84@yahoo.com; c.m.ott@nasa.gov; epsilon3@bioinfo.uh.edu; yfofanov@bioinfo.uh.edu; duane.l.pierson@nasa.gov; rcwwww@gmail.com; fox@uh.edu NR 47 TC 26 Z9 31 U1 1 U2 13 PU BIOMED CENTRAL LTD PI LONDON PA MIDDLESEX HOUSE, 34-42 CLEVELAND ST, LONDON W1T 4LB, ENGLAND SN 1471-2180 J9 BMC MICROBIOL JI BMC Microbiol. PD MAR 7 PY 2007 VL 7 AR 15 DI 10.1186/1471-2180-7-15 PG 16 WC Microbiology SC Microbiology GA 158WP UT WOS:000245826300001 PM 17343762 ER PT J AU Hollingsworth, JL Young, RE Schubert, G Covey, C Grossman, AS AF Hollingsworth, J. L. Young, R. E. Schubert, G. Covey, C. Grossman, A. S. TI A simple-physics global circulation model for Venus: Sensitivity assessments of atmospheric superrotation SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID MERIDIONAL CIRCULATION; SIMULATIONS; ROTATION; WAVES; AGCM; GCM AB A 3D global circulation model is adapted to the atmosphere of Venus to explore the nature of the planet's atmospheric superrotation. The model employs the full meteorological primitive equations and simplified forms for diabatic and other nonconservative forcings. It is therefore economical for performing very long simulations. To assess circulation equilibration and the occurrence of atmospheric superrotation, the climate model is run for 10,000-20,000 day integrations at 4 degrees x 5 degrees latitude-longitude horizontal resolution, and 56 vertical levels (denoted L56). The sensitivity of these simulations to imposed Venus-like diabatic heating rates, momentum dissipation rates, and various other key parameters (e.g., near-surface momentum drag), in addition to model configuration (e.g., low versus high vertical domain and number of atmospheric levels), is examined. We find equatorial superrotation in several of our numerical experiments, but the magnitude of superrotation is often less than observed. Further, the meridional structure of the mean zonal overturning (i.e., Hadley circulation) can consist of numerous cells which are symmetric about the equator and whose depth scale appears sensitive to the number of vertical layers imposed in the model atmosphere. We find that when realistic diabatic heating is imposed in the lowest several scales heights, only extremely weak atmospheric superrotation results. C1 NASA, Ames Res Ctr, San Jose State Univ Fdn, Moffett Field, CA 94035 USA. NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA. Univ Calif Los Angeles, Dept Earth & Space Sci, Los Angeles, CA 90095 USA. Univ Calif Los Angeles, Inst Geophys & Planetary Phys, Los Angeles, CA 90095 USA. Lawrence Livermore Natl Lab, Climate & Carbon Sci Grp, Livermore, CA 94551 USA. RP Hollingsworth, JL (reprint author), NASA, Ames Res Ctr, San Jose State Univ Fdn, MS 245-3, Moffett Field, CA 94035 USA. EM jeffh@humbabe.arc.nasa.gov; richardeyoung2@aol.com; schubert@ucla.edu; covey1@llnl.gov; bsgasg@sbcglobal.net NR 20 TC 32 Z9 32 U1 1 U2 5 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD MAR 7 PY 2007 VL 34 IS 5 AR L05202 DI 10.1029/2006GL028567 PG 5 WC Geosciences, Multidisciplinary SC Geology GA 145WV UT WOS:000244897400002 ER PT J AU McDonald, FB Stone, EC Cummings, AC Webber, WR Heikkila, BC Lal, N AF McDonald, F. B. Stone, E. C. Cummings, A. C. Webber, W. R. Heikkila, B. C. Lal, N. TI Anomalous cosmic rays in the distant heliosphere and the reversal of the Sun's magnetic polarity in Cycle 23 SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID TERMINATION-SHOCK; CORONAL HOLES; SOLAR MAXIMUM; FIELD; HELIOSHEATH; NITROGEN; OXYGEN; IONS AB Beginning in early June 2001 and extending over a similar to 3 month period the Cosmic Ray Subsystem (CRS) experiment on Voyager 1 (80.3 AU, 34 degrees N) observed a rapid transition in the energy of the peak intensity of anomalous cosmic ray (ACR) He from similar to 11 MeV/n to similar to 25 MeV/n. One month later there began a similar spectral shift at Voyager 2 (64.7 AU, 24 degrees S). When these ACR transition times are extrapolated back from the estimated location of the heliospheric termination shock (TS) to the Sun (similar to 1 year) there is reasonable agreement with the range of times obtained for the polarity reversal of the interplanetary magnetic field (IPB) in the northern hemisphere near the Sun and the later reversal in the south. We interpret these changes in the ACR spectra as giving a global view of the interplanetary field reversal at the TS and confirmation of the important role of the TS in controlling the ACRs. C1 Univ Maryland, Inst Phys Sci & Technol, College Pk, MD 20742 USA. New Mexico State Univ, Dept Phys & Astron, Las Cruces, NM 88003 USA. CALTECH, Space Radiat Lab, Pasadena, CA 91125 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP McDonald, FB (reprint author), Univ Maryland, Inst Phys Sci & Technol, College Pk, MD 20742 USA. EM fmcdonal@umd.edu NR 23 TC 5 Z9 5 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 EI 1944-8007 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD MAR 7 PY 2007 VL 34 IS 5 AR L05105 DI 10.1029/2006GL028932 PG 5 WC Geosciences, Multidisciplinary SC Geology GA 145WV UT WOS:000244897400005 ER PT J AU Holloway, G Dupont, F Golubeva, E Hakkinen, S Hunke, E Jin, M Karcher, M Kauker, F Maltrud, M Maqueda, MAM Maslowski, W Platov, G Stark, D Steele, M Suzuki, T Wang, J Zhang, J AF Holloway, G. Dupont, F. Golubeva, E. Haekkinen, S. Hunke, E. Jin, M. Karcher, M. Kauker, F. Maltrud, M. Maqueda, M. A. Morales Maslowski, W. Platov, G. Stark, D. Steele, M. Suzuki, T. Wang, J. Zhang, J. TI Water properties and circulation in Arctic Ocean models SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID WORLD OCEAN; HALOCLINE; PARAMETERIZATION; ADVECTION; LAYER; TRANSPORT; DYNAMICS; SCHEME; FLUX AB As a part of the Arctic Ocean Model Intercomparison Project, results from 10 Arctic ocean/ice models are intercompared over the period 1970 through 1999. Models' monthly mean outputs are laterally integrated over two subdomains (Amerasian and Eurasian basins), then examined as functions of depth and time. Differences in such fields as averaged temperature and salinity arise from models' differences in parameterizations and numerical methods and from different domain sizes, with anomalies that develop at lower latitudes carried into the Arctic. A systematic deficiency is seen as AOMIP models tend to produce thermally stratified upper layers rather than the "cold halocline", suggesting missing physics perhaps related to vertical mixing or to shelf-basin exchanges. Flow fields pose a challenge for intercomparison. We introduce topostrophy, the vertical component of V x del D where V is monthly mean velocity and del D is the gradient of total depth, characterizing the tendency to follow topographic slopes. Positive topostrophy expresses a tendency for cyclonic "rim currents". Systematic differences of models' circulations are found to depend strongly upon assumed roles of unresolved eddies. C1 Inst Ocean Sci, Dept Fisheries & Oceans, Sidney, BC V8L 4B2, Canada. Univ Laval, Ste Foy, PQ G1K 7P4, Canada. Russian Acad Sci, Inst Computat Math & Math Geophys, Siberian Branch, Novosibirsk 630090, Russia. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Los Alamos Natl Lab, Climate Ocean & Sea Ice Modeling Program, Los Alamos, NM 87545 USA. Univ Alaska Fairbanks, Int Arctic Res Ctr, Fairbanks, AK 99775 USA. Alfred Wegener Inst Polar & Marine Res, D-27515 Bremerhaven, Germany. USN, Postgrad Sch, Dept Oceanog, Monterey, CA 93943 USA. Proudman Oceanog Lab, Liverpool L3 5DA, Merseyside, England. Univ Washington, Appl Phys Lab, Seattle, WA 98105 USA. Frontier Res Ctr Global Change, Kanagawa 236001, Japan. RP Holloway, G (reprint author), Inst Ocean Sci, Dept Fisheries & Oceans, Sidney, BC V8L 4B2, Canada. RI Hakkinen, Sirpa/E-1461-2012; Golubeva, Elena/A-6606-2014; Platov, Gennady/A-6598-2014; Jin, Meibing/F-7666-2010 OI Golubeva, Elena/0000-0001-6178-6789; Platov, Gennady/0000-0003-3142-0721; NR 41 TC 63 Z9 65 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9275 EI 2169-9291 J9 J GEOPHYS RES-OCEANS JI J. Geophys. Res.-Oceans PD MAR 7 PY 2007 VL 112 IS C4 AR C04S03 DI 10.1029/2006JC003642 PG 18 WC Oceanography SC Oceanography GA 145XT UT WOS:000244899800001 ER PT J AU Perovich, DK Nghiem, SV Markus, T Schweiger, A AF Perovich, Donald K. Nghiem, Son V. Markus, Thorsten Schweiger, Axel TI Seasonal evolution and interannual variability of the local solar energy absorbed by the Arctic sea ice-ocean system SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID POLARIMETRIC SIGNATURES; SURFACE CONDITIONS; ALBEDO; COVER; SATELLITE; SUMMER; BUDGET; SHEBA; FLUX; PARAMETERIZATIONS AB The melt season of the Arctic sea ice cover is greatly affected by the partitioning of the incident solar radiation between reflection to the atmosphere and absorption in the ice and ocean. This partitioning exhibits a strong seasonal cycle and significant interannual variability. Data in the period 1998, 2000-2004 were analyzed in this study. Observations made during the 1997-1998 SHEBA (Surface HEat Budget of the Arctic Ocean) field experiment showed a strong seasonal dependence of the partitioning, dominated by a five-phase albedo evolution. QuikSCAT scatterometer data from the SHEBA region in 1999-2004 were used to further investigate solar partitioning in summer. The time series of scatterometer data were used to determine the onset of melt and the beginning of freezeup. This information was combined with SSM/I-derived ice concentration, TOVS-based estimates of incident solar irradiance, and SHEBA results to estimate the amount of solar energy absorbed in the ice-ocean system for these years. The average total solar energy absorbed in the ice-ocean system from April through September was 900 MJ m(-2). There was considerable interannual variability, with a range of 826 to 1044 MJ m(-2). The total amount of solar energy absorbed by the ice and ocean was strongly related to the date of melt onset, but only weakly related to the total duration of the melt season or the onset of freezeup. The timing of melt onset is significant because the incident solar energy is large and a change at this time propagates through the entire melt season, affecting the albedo every day throughout melt and freezeup. C1 USA, Cold Reg Res & Engn Lab, Engineer Res & Dev Ctr, Hanover, NH 03755 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Polar Sci Ctr, Appl Phys Lab, Seattle, WA 98195 USA. RP Perovich, DK (reprint author), USA, Cold Reg Res & Engn Lab, Engineer Res & Dev Ctr, 72 Lyme Rd, Hanover, NH 03755 USA. EM donald.k.perovich@erdc.usace.army.mil RI Markus, Thorsten/D-5365-2012 NR 45 TC 68 Z9 69 U1 1 U2 19 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-OCEANS JI J. Geophys. Res.-Oceans PD MAR 6 PY 2007 VL 112 IS C3 AR C03005 DI 10.1029/2006JC003558 PG 13 WC Oceanography SC Oceanography GA 145XP UT WOS:000244899400002 ER PT J AU Dobe, Z Szego, K Quest, KB Shapiro, VD Hartle, RE Sittler, EC AF Dobe, Zoltan Szego, Karoly Quest, Kevin B. Shapiro, Vitali D. Hartle, R. E. Sittler, E. C., Jr. TI Nonlinear evolution of modified two-stream instability above ionosphere of Titan: Comparison with the data of the Cassini Plasma Spectrometer SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID MAGNETOSPHERIC INTERACTION; MAGNETIC BARRIER; DAYSIDE MANTLE; WAVE ACTIVITY; SOLAR-WIND; MHD MODEL; VENUS; IONS; MARS; ENVIRONMENT AB The ionosphere of Titan, moon of Saturn, is directly exposed to the streaming plasma either of magnetospheric or solar wind origin. A turbulent interaction region is formed, called here flowside plasma mantle, where both cold ionospheric and hot streaming plasma are present at comparable densities. Within the framework of a one-dimensional electromagnetic hybrid simulation using realistic electron mass we have shown that significant wave activity may be generated because of a modified two-stream instability (MTSI). Having its free energy in the relative drift between the streaming ion flow and the ionospheric ions MTSI is very effective in generating "anomalous viscosity'' type interaction leading to significant bulk velocity loss of the proton component of the external plasma flow and turbulent heating of the ionospheric ions. The stochastic energy transfer from the streaming plasma to the ionospheric ions may also increase the tailward planetary ion escape by collective pickup mechanism enhancing the rate of erosion of the atmosphere of Titan. We predict significant wave activity within the characteristic frequency range of about 1-10 Hz and at saturated wave electric field levels of about 5-25 mV/m. Similarly, according to our model calculations superthermal charged particles of ionospheric origin with kinetic energies of about few tens of eV are expected to be detectable by the charged particle analyzers onboard of Cassini spacecraft close to the upper edge of Titan's ionosphere. C1 Hungarian Acad Sci, KFKI Res Inst Particle & Nucl Phys, H-1525 Budapest, Hungary. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Calif San Diego, Dept Elect & Comp Engn, La Jolla, CA 92093 USA. GE Co, Consumer & Ind Prod, Budapest, Hungary. RP Dobe, Z (reprint author), Hungarian Acad Sci, KFKI Res Inst Particle & Nucl Phys, POB 49, H-1525 Budapest, Hungary. EM zoltan.dobe@ge.com; szego@rmki.kfki.hu NR 56 TC 4 Z9 4 U1 2 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9380 EI 2169-9402 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD MAR 6 PY 2007 VL 112 IS A3 AR A03203 DI 10.1029/2006JA011770 PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 145XY UT WOS:000244900300002 ER PT J AU Gao, JS Zmuidzinas, J Mazin, BA LeDuc, HG Day, PK AF Gao, Jiansong Zmuidzinas, Jonas Mazin, Benjamin A. LeDuc, Henry G. Day, Peter K. TI Noise properties of superconducting coplanar waveguide microwave resonators SO APPLIED PHYSICS LETTERS LA English DT Article ID SINGLE-CRYSTAL SILICON; LOW-TEMPERATURES; 2-LEVEL SYSTEMS; MECHANICAL-PROPERTIES; SPECTRAL DIFFUSION; SQUID MULTIPLEXER; GLASSES; MOLECULES; PHOTON AB The authors have measured noise in thin-film superconducting coplanar waveguide resonators. This noise appears entirely as phase noise, equivalent to a jitter of the resonance frequency. In contrast, amplitude fluctuations are not observed at the sensitivity of their measurement. The ratio between the noise power in the phase and amplitude directions is large, in excess of 30 dB. These results have important implications for resonant readouts of various devices such as detectors, amplifiers, and qubits. They suggest that the phase noise is due to two-level systems in dielectric materials. (c) 2007 American Institute of Physics. C1 CALTECH, Dept Phys, Pasadena, CA 91125 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Gao, JS (reprint author), CALTECH, Dept Phys, Pasadena, CA 91125 USA. EM jiansong@caltech.edu RI Mazin, Ben/B-8704-2011 OI Mazin, Ben/0000-0003-0526-1114 NR 29 TC 111 Z9 111 U1 3 U2 17 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD MAR 5 PY 2007 VL 90 IS 10 AR 102507 DI 10.1063/1.2711770 PG 3 WC Physics, Applied SC Physics GA 144JG UT WOS:000244791700069 ER PT J AU Wu, SL Mickley, LJ Jacob, DJ Logan, JA Yantosca, RM Rind, D AF Wu, Shiliang Mickley, Loretta J. Jacob, Daniel J. Logan, Jennifer A. Yantosca, Robert M. Rind, David TI Why are there large differences between models in global budgets of tropospheric ozone? SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID GENERAL-CIRCULATION MODEL; NITROGEN-OXIDE EMISSIONS; UNITED-STATES; SATELLITE-OBSERVATIONS; NONMETHANE HYDROCARBONS; CLIMATE-CHANGE; NOX PRODUCTION; LIGHTNING NOX; MINERAL DUST; 3-D MODELS AB Global 3-D tropospheric chemistry models in the literature show large differences in global budget terms for tropospheric ozone. The ozone production rate in the troposphere, P(O-x), varies from 2300 to 5300 Tg yr(-1) across models describing the present-day atmosphere. The ensemble mean of P(O-x) in models from the post-2000 literature is 35% higher than that compiled in the Intergovernmental Panel on Climate Change (IPCC) Third Assessment Report (TAR). Simulations conducted with the GEOS-Chem model using two different assimilated meteorological data sets for 2001 (GEOS-3 and GEOS-4), as well as 3 years of GISS GCM meteorology, show P(O-x) values in the range 4250-4700 Tg yr(-1); the differences appear mostly because of clouds. Examination of the evolution of P(O-x) over the GEOS-Chem model history shows major effects from changes in heterogeneous chemistry, the lightning NOx source, and the yield of organic nitrates from isoprene oxidation. Multivariate statistical analysis of model budgets in the literature indicates that 74% of the variance in P(O-x) across models can be explained by differences in NOx emissions, inclusion of nonmethane volatile organic compounds (NMVOCs, mostly biogenic isoprene), and ozone influx from stratosphere-troposphere exchange (STE). Higher NOx emissions, more widespread inclusion of NMVOC chemistry, and weaker STE in the more recent models increase ozone production; however, the effect of NMVOCs does not appear generally sensitive to the magnitude of emissions within the range typically used in models (500-900 Tg C yr(-1)). We find in GEOS-Chem that P(O-x) saturates when NMVOC emissions exceed 200 Tg C yr(-1) because of formation of organic nitrates from isoprene oxidation, providing an important sink for NOx. C1 Harvard Univ, Div Engn & Appl Sci, Cambridge, MA USA. Harvard Univ, Dept Earth & Planetary Sci, Cambridge, MA USA. NASA, Goddard Inst Space Studies, New York, NY 10025 USA. RP Wu, SL (reprint author), Harvard Univ, Div Engn & Appl Sci, Cambridge, MA USA. EM wu18@fas.harvard.edu RI Mickley, Loretta/D-2021-2012; Yantosca, Robert/F-7920-2014; Chem, GEOS/C-5595-2014 OI Mickley, Loretta/0000-0002-7859-3470; Yantosca, Robert/0000-0003-3781-1870; NR 85 TC 135 Z9 139 U1 3 U2 39 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAR 3 PY 2007 VL 112 IS D5 AR D05302 DI 10.1029/2006JD007801 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 143GN UT WOS:000244708200004 ER PT J AU Kobayashi, S Oguchi, T Tanelli, S Im, E AF Kobayashi, Satoru Oguchi, Tomohiro Tanelli, Simone Im, Eastwood TI Backscattering enhancement on spheroid-shaped hydrometeors: Considerations in water and ice particles of uniform size and Marshall-Palmer distributed rains SO RADIO SCIENCE LA English DT Article ID RADIATIVE-TRANSFER EQUATION; MULTIPLE-SCATTERING; COHERENT BACKSCATTERING; SPHERICAL SCATTERERS; WEAK-LOCALIZATION; DISORDERED MEDIA; 34.8 GHZ; RADAR; LIGHT; WAVES AB [1] A second-order scattering theory is derived for uniformly oriented spheroidal hydrometeors with a general drop size distribution in a single layer. Effects of backscattering enhancement are evaluated for a nadir pointing radar with a finite beam width at millimeter wave frequencies. Spheroids of uniform size are first studied to characterize the deviations from the spherical theories. For water spheroids, the difference between the cross term (backscattering enhancement term) and the ladder term (conventional multiscattering term) becomes larger as the spheroids deviate from the spherical shape. On the contrary, for ice spheroids, this difference is negligible. Marshall-Palmer distributed rains with Pruppacher-Pitter-form drops are studied using the spheroidal approximation. The results confirm the validity of the spherical approximation used in the preceding works within the accuracy limit of measurement. In the Marshall-Palmer distributed rains, the second-order scattering effect becomes serious as the footprint radius increases. Hence the second-order scattering is to be taken into account for accurate measurement of hydrometeor reflectivity for a spaceborne radar because of its large footprint radius. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Kanto Gakuin Univ, Dept Elect & Elect Engn, Kanagawa 2368501, Japan. RP Kobayashi, S (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 300-243, Pasadena, CA 91109 USA. EM satoru@radar-sci.jpl.nasa.gov NR 38 TC 10 Z9 10 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0048-6604 J9 RADIO SCI JI Radio Sci. PD MAR 3 PY 2007 VL 42 IS 2 AR RS2001 DI 10.1029/2006RS003503 PG 16 WC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications SC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications GA 143HK UT WOS:000244710700001 ER PT J AU Kwok, R AF Kwok, Ron TI Near zero replenishment of the Arctic multiyear sea ice cover at the end of 2005 summer SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID OCEAN AB The remarkably low Arctic multiyear (MY) sea ice coverage following the summer of 2005 is placed in the context of its variability over the past seven years (2000-2006). Annual cycles of MY ice coverage, from QuikSCAT and satellite passive ice motion, show that the replenishment of MY ice area at the end of this summer is near zero (0.1 x 10(6) km(2)) compared to the previous five summers of 1.0, 1.2, 0.4, 0.4, and 0.9 x 10(6) km(2). This is examined in terms of anomalies in ice export and the record of freezing (F-DD) and melting degree-days (M-DD). The 2005 summer (Jun-Sep) saw the highest Fram Strait ice export (>0.25 x 10(6) km(2)) compared to the 7-year mean of 0.14 x 10(6) km(2). This directly explains similar to 40% of the decrease in MY coverage of 0.6 x 10(6) km(2) between Jan 2005 and Jan 2006. The cumulative effects of the recent warmer winters and summers, relative to the longer-term record since 1958, explain the balance. For this short record, the combination of spatially averaged FDD and MDD anomalies of the preceding year explain similar to 63% of the variance in the replenishment areas. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Kwok, R (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM ron.kwok@jpl.nasa.gov RI Kwok, Ron/A-9762-2008 OI Kwok, Ron/0000-0003-4051-5896 NR 10 TC 47 Z9 48 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD MAR 2 PY 2007 VL 34 IS 5 AR L05501 DI 10.1029/2006GL028737 PG 6 WC Geosciences, Multidisciplinary SC Geology GA 143GD UT WOS:000244707200006 ER PT J AU Kuzmanoski, M Box, MA Schmid, B Box, GP Wang, J Russell, PB Bates, D Jonsson, HH Welton, EJ Seinfeld, JH AF Kuzmanoski, M. Box, M. A. Schmid, B. Box, G. P. Wang, J. Russell, P. B. Bates, D. Jonsson, H. H. Welton, E. J. Seinfeld, J. H. TI Aerosol properties computed from aircraft-based observations during the ACE-Asia campaign: 2. A case study of lidar ratio closure SO AEROSOL SCIENCE AND TECHNOLOGY LA English DT Article ID TO-BACKSCATTER RATIO; SPECTRAL-RESOLUTION LIDAR; RAMAN LIDAR; OPTICAL-PROPERTIES; TROPOSPHERIC AEROSOLS; RADIATIVE PROPERTIES; VERTICAL STRUCTURE; RELATIVE-HUMIDITY; SIZE DISTRIBUTION; COLUMN CLOSURE AB For a vertical profile with three distinct layers (marine boundary, pollution, and dust layers), observed during the ACE-Asia campaign, we carried out a comparison between the modeled lidar ratio vertical profile and that obtained from co-located airborne NASA AATS-14 sunphotometer and shipborne Micro-Pulse Lidar (MPL) measurements. The vertically resolved lidar ratio was calculated from two size distribution vertical profiles one obtained by inversion of sunphotometer-derived extinction spectra, and one measured in-situ-combined with the same refractive index model based on aerosol chemical composition. The aerosol model implies single scattering albedos of 0.78-0.81 and 0.93-0.96 at 0.523 mu m (the wavelength of the lidar measurements), in the pollution and dust layers, respectively. The lidar ratios calculated from the two size distribution profiles agree closely in the dust layer; they are however, significantly lower than the lidar ratios derived from combined lidar and sunphotometer measurements. Uncertainties in aerosol size distributions and refractive index only partly explain these differences, suggesting that particle nonsphericity in this layer is an additional explanation. In the pollution layer, the two size distribution profiles yield lidar ratios that agree within the estimated uncertainties. The retrieved size distributions result in a lidar ratio which is in closer agreement with that derived, from lidar/sunphotometer measurements in this layer, with still large differences at certain altitudes (the largest relative difference was 46%). We explain these differences by non-uniqueness of the result of the size distribution retrieval, by a lack of information on the mixing state of particles, and the vertical variability of the particle refractive index. C1 Univ New S Wales, Sch Phys, Sydney, NSW 2052, Australia. Bay Area Environm Res Inst, Sonoma, CA USA. Brookhaven Natl Lab, Upton, NY 11973 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ Miami, Dept Phys, Coral Gables, FL 33124 USA. CIRPAS, Marina, CA USA. NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. CALTECH, Dept Chem Engn, Pasadena, CA 91125 USA. RP Kuzmanoski, M (reprint author), Univ New S Wales, Sch Phys, Sydney, NSW 2052, Australia. EM mkuzm@phys.unsw.edu.au RI Welton, Ellsworth/A-8362-2012; Wang, Jian/G-9344-2011 NR 53 TC 4 Z9 4 U1 0 U2 3 PU TAYLOR & FRANCIS INC PI PHILADELPHIA PA 325 CHESTNUT ST, SUITE 800, PHILADELPHIA, PA 19106 USA SN 0278-6826 J9 AEROSOL SCI TECH JI Aerosol Sci. Technol. PD MAR PY 2007 VL 41 IS 3 BP 231 EP 243 DI 10.1080/02786820601146977 PG 13 WC Engineering, Chemical; Engineering, Mechanical; Environmental Sciences; Meteorology & Atmospheric Sciences SC Engineering; Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA 150UT UT WOS:000245245800001 ER PT J AU Paxson, DE Wernet, MP John, WT AF Paxson, Daniel E. Wernet, Mark P. John, Wentworth T. TI Experimental investigation of unsteady thrust augmentation using a speaker-driven jet SO AIAA JOURNAL LA English DT Article AB An experimental investigation is described in which a simple speaker-driven jet was used as a pulsed thrust source (driver) for an ejector configuration. The objectives of the investigation were twofold. The first was to expand the experimental body of evidence showing that an unsteady thrust source, combined with a properly sized ejector generally yields higher thrust augmentation values than a similarly sized, steady driver of equivalent thrust. The second objective was to identify characteristics of the unsteady driver that may be useful for sizing ejectors, and for predicting the thrust augmentation levels that may be achieved. The speaker-driven jet provided a convenient source for the investigation because it is entirely unsteady (i.e., it has no mean velocity component) and because relevant parameters such as frequency, time-averaged thrust, and diameter are easily variable. The experimental setup will be described, as will the two main measurements techniques employed. These are thrust and digital particle imaging velocimetry of the driver. It will be shown that thrust augmentation values as high as 1.8 were obtained, that the diameter of the best ejector scaled with the dimensions of the emitted vortex, and that the so-called formation time serves as a useful dimensionless parameter by which to characterize the jet and predict performance. C1 NASA, John H Gleen Res Ctr, Instrumentat & Controls Div, Cleveland, OH 44135 USA. Ohio Aerosp Inst, Instrumentat & Controls Div, Cleveland, OH 44135 USA. RP Paxson, DE (reprint author), NASA, John H Gleen Res Ctr, Instrumentat & Controls Div, Cleveland, OH 44135 USA. NR 15 TC 8 Z9 8 U1 0 U2 5 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0001-1452 J9 AIAA J JI AIAA J. PD MAR PY 2007 VL 45 IS 3 BP 607 EP 614 DI 10.2514/1.18449 PG 8 WC Engineering, Aerospace SC Engineering GA 144WO UT WOS:000244827300011 ER PT J AU Chretien, JP Anyamba, A Bedno, SA Breiman, RF Sang, R Sergon, K Powers, AM Onyango, CO Small, J Tucker, CJ Linthicum, KJ AF Chretien, Jean-Paul Anyamba, Assaf Bedno, Sheryl A. Breiman, Robert F. Sang, Rosemary Sergon, Kibet Powers, Ann M. Onyango, Clayton O. Small, Jennifer Tucker, Compton J. Linthicum, Kenneth J. TI Drought-associated Chikungunya emergence along coastal East Africa SO AMERICAN JOURNAL OF TROPICAL MEDICINE AND HYGIENE LA English DT Article ID AEDES-AEGYPTI; VEGETATION; EPIDEMICS; VIRUS; KENYA AB Epidemics of chikungunya fever, an Aedes spp.-borne viral disease, affected hundreds of thousands of people in western Indian Ocean islands and India during 2005-2006. The initial outbreaks occurred in coastal Kenya (Lamu, then Mombasa) in 2004. We investigated eco-climatic conditions associated with chikungunya fever emergence along coastal Kenya using epidemiologic investigations and satellite data. Unusually dry, warm conditions preceded the outbreaks, including the driest since 1998 for some of the coastal regions. Infrequent replenishment of domestic water stores and elevated temperatures may have facilitated Chikungunya virus transmission. These results suggest that drought-affected populations may be at heightened risk for chikungunya fever, and underscore the need for safe water storage during drought relief operations. C1 Walter Reed Army Inst Res, Dept Def Global Emerging Infect Surveillance & Re, Div Prevent Med, Silver Spring, MD 20910 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. USA, Med Res Unit, Nairobi, Kenya. CDC, Int Emerging Infect Program, Nairobi, Kenya. Kenya Govt Med Res Ctr, Nairobi, Kenya. CDC, Field Epidemiol & Lab Training Program, Nairobi, Kenya. CDC, Div Vector Borne Infect Dis, Ft Collins, CO USA. USDA ARS, Ctr Med Agr & Vet Entomol, Gainesville, FL 32611 USA. RP Chretien, JP (reprint author), Walter Reed Army Inst Res, Dept Def Global Emerging Infect Surveillance & Re, Div Prevent Med, 503 Robert Grant Ave, Silver Spring, MD 20910 USA. EM Jean-Paul.Chretien@na.amedd.army.mil; Assaf@ltpmail.gsfc.nasa.gov; sbedno@wrp-nbo.org; RBreiman@ke.cdc.gov; Rsang@kemri.org; kibetsergon@yahoo.com; akp7@cdc.gov; conyango@mrc.gm; jsmall@pop900.gsfc.nasa.gov; compton@ltpmailx.gsfc.nasa.gov; klinthicum@gainesville.usda.ufl.edu RI Valle, Ruben/A-7512-2013 NR 15 TC 84 Z9 89 U1 3 U2 11 PU AMER SOC TROP MED & HYGIENE PI MCLEAN PA 8000 WESTPARK DR, STE 130, MCLEAN, VA 22101 USA SN 0002-9637 J9 AM J TROP MED HYG JI Am. J. Trop. Med. Hyg. PD MAR PY 2007 VL 76 IS 3 BP 405 EP 407 PG 3 WC Public, Environmental & Occupational Health; Tropical Medicine SC Public, Environmental & Occupational Health; Tropical Medicine GA 146FA UT WOS:000244918700002 PM 17360859 ER PT J AU Deserranno, D Kassemi, M Thomas, JD AF Deserranno, Dimitri Kassemi, Mohammad Thomas, James D. TI Incorporation of myofilament activation mechanics into a lumped model of the human heart SO ANNALS OF BIOMEDICAL ENGINEERING LA English DT Article DE lumped parameter model; actin-myosin; calcium binding; myofilament activation; heart; cardiovascular system ID PRESSURE-VOLUME RELATIONS; BLOOD-FLOW; MITRAL REGURGITATION; ORTHOSTATIC STRESS; PARAMETER MODEL; FORCE RELATIONS; CARDIAC-MUSCLE; VALVE AREA; VALIDATION; SYSTEM AB The success and usefulness of lumped cardiovascular models are directly dependent on the physiological fidelity of their formulation. In most existing lumped formulations for the heart, the compliance of the chamber is modeled based on its electrical analog, the capacitor. This has traditionally resulted in the use of a pre-described time-varying stiffness modulus for simulating the cardiac contractions. Unfortunately, such a time-varying stiffness does not include any physiological contractile machinery and thus no dependency on fiber sarcomere length and intracellular calcium concentrations, key mechanisms responsible for proper cardiac function. In this paper a lumped cardiovascular model is presented that is based on the incorporation of detailed myofilament activation for simulating the ventricular calcium binding and crossbridging mechanism. Upon validation against experimental data, it is shown that the new myofilament activation-based model considerably increases the physiological validity and internal consistency of the cardiovascular simulations in comparison to the traditional variable compliance-based models. It is also shown, through specific case studies, that the present model can serve as a quick response tool for testing various hypotheses concerning the impact of the calcium binding and crossbridge kinetics on the overall performance of the cardiovascular system. C1 NASA, Glenn Res Ctr, Natl Ctr Space Explorat Res, Cleveland, OH 44135 USA. Cleveland Clin Fdn, Cleveland, OH 44195 USA. RP Deserranno, D (reprint author), NASA, Glenn Res Ctr, Natl Ctr Space Explorat Res, 21000 Brookpk Rd MS 110-3, Cleveland, OH 44135 USA. EM dimitri.deserranno@gmail.com NR 37 TC 2 Z9 2 U1 0 U2 2 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0090-6964 EI 1573-9686 J9 ANN BIOMED ENG JI Ann. Biomed. Eng. PD MAR PY 2007 VL 35 IS 3 BP 321 EP 336 DI 10.1007/s10439-006-9234-1 PG 16 WC Engineering, Biomedical SC Engineering GA 137KR UT WOS:000244292000001 PM 17219084 ER PT J AU Burriss, TL AF Burriss, Theresa L. TI Living an inspired life: Teaching social activism (Steve Fisher) SO APPALACHIAN JOURNAL LA English DT Editorial Material C1 Radford Univ, LARC, Radford, VA 24142 USA. RP Burriss, TL (reprint author), Radford Univ, LARC, Radford, VA 24142 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU APPALACHIAN STATE UNIV PI BOONE PA BELK LIBRARY, BOX 32026, BOONE, NC 28608 USA SN 0090-3779 J9 APPALACHIAN J JI Appalach. J. PD SPR-SUM PY 2007 VL 34 IS 3-4 BP 418 EP 420 PG 3 WC History; Literary Reviews SC History; Literature GA 239SO UT WOS:000251538200028 ER PT J AU Christensen, LE Webster, CR Yang, RQ AF Christensen, Lance E. Webster, Christopher R. Yang, Rui Q. TI Aircraft and balloon in situ measurements of methane and hydrochloric acid using interband cascade lasers SO APPLIED OPTICS LA English DT Article ID CONTINUOUS-WAVE OPERATION; ABSORPTION SPECTROMETER; ROOM-TEMPERATURE; DIODE-LASERS; MU-M; N2O; CH4; (CH4)-C-13/(CH4)-C-12; STRATOSPHERE; DESIGN AB Aircraft and balloon in situ measurements of CH4 and HCl using cw distributed feedback (DFB) inter-band cascade (IC) lasers are reported. In the stratosphere and upper troposphere, sensitivity toward CH4 and HCl is better than 10 ppbv (1 s) and 90 pptv (50 s), respectively. These are the first flight measurements of trace gas-phase species using cw DFB IC lasers. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Christensen, LE (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM lance.christensen@jpl.nasa.gov NR 44 TC 10 Z9 11 U1 2 U2 9 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1559-128X EI 2155-3165 J9 APPL OPTICS JI Appl. Optics PD MAR 1 PY 2007 VL 46 IS 7 BP 1132 EP 1138 DI 10.1364/AO.46.001132 PG 7 WC Optics SC Optics GA 140JM UT WOS:000244500800016 PM 17304312 ER PT J AU Sun, WB Videen, G Lin, B Hu, YX AF Sun, Wenbo Videen, Gorden Lin, Bing Hu, Yongxiang TI Modeling light scattered from and transmitted through dielectric periodic structures on a substrate SO APPLIED OPTICS LA English DT Article ID SURFACE SCATTERING; ROUGH SURFACES; ELECTROMAGNETIC SCATTERING; FDTD; BACKSCATTERING; PARTICLES; MEDIA; WAVES AB Light scattering and transmission by rough surfaces are of considerable interest in a variety of applications including remote sensing and characterization of surfaces. In this work, the finite-difference time-domain technique is applied to calculate the scattered and transmitted electromagnetic fields of an infinite periodic rough surface. The elements of the Mueller matrix for scattered light are calculated by an integral of the near fields over a significant number of periods of the surface. The normalized Mueller matrix elements of the scattered light and the spatial distribution of the transmitted flux for a monolayer of micrometer-sized dielectric spheres on a silicon substrate are presented. The numerical results show that the nonzero Mueller matrix elements for scattering from a surface consisting of a monolayer of dielectric spheres on a silicon substrate have specific maxima at some scattering angles. These maxima may be used in the characterization of features of the surface. For light transmitted through the monolayer of spheres, our results show that the transmitted energy focuses around the ray passing through centers of the spheres. At other locations, the transmitted flux is very small. Therefore, micrometer-sized dielectric spheres might be placed on a semiconductor surface to burn nanometer-sized holes in a layer using laser pulses. The method may also be useful in the assembly of periodic microstructures on surfaces. C1 Hampton Univ, Ctr Atmospher Sci, Hampton, VA 23668 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Sun, WB (reprint author), Hampton Univ, Ctr Atmospher Sci, Hampton, VA 23668 USA. EM w.sun@larc.nasa.gov RI Hu, Yongxiang/K-4426-2012 NR 42 TC 4 Z9 4 U1 0 U2 4 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1559-128X EI 2155-3165 J9 APPL OPTICS JI Appl. Optics PD MAR 1 PY 2007 VL 46 IS 7 BP 1150 EP 1156 DI 10.1364/AO.46.001150 PG 7 WC Optics SC Optics GA 140JM UT WOS:000244500800019 PM 17304315 ER PT J AU Vasudev, R AF Vasudev, R. TI Wavelength modulated cavity enhanced absorption spectroscopy of ammonia at 1994 nm SO APPLIED PHYSICS B-LASERS AND OPTICS LA English DT Article ID ATMOSPHERE; NITROGEN; RING; SPECTROMETER; METHANE; MARS AB We describe the sensitive detection of ammonia by wavelength modulated cavity enhanced infrared tunable diode laser absorption spectroscopy at 1994 nm. The spectrometer can measure a fractional absorption of similar to 10(-5) for an absorption pathlength of a few kilometers. The spectral resolution and sensitivity are sufficient to measure ammonia isotopomers ((NH3)-N-14, (NH3)-N-15) in planetary atmospheres. The spectrometer is miniaturisable, so a future multiple-species version will be highly suitable for in situ planetary exploration and life-detection. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Vasudev, R (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM rvasudev@jpl.nasa.gov NR 27 TC 8 Z9 8 U1 0 U2 1 PU SPRINGER PI NEW YORK PA 233 SPRING STREET, NEW YORK, NY 10013 USA SN 0946-2171 J9 APPL PHYS B-LASERS O JI Appl. Phys. B-Lasers Opt. PD MAR PY 2007 VL 87 IS 1 BP 163 EP 167 DI 10.1007/s00340-006-2486-5 PG 5 WC Optics; Physics, Applied SC Optics; Physics GA 144UA UT WOS:000244820600029 ER PT J AU Djouimaa, S Messaoudi, L Giel, PW AF Djouimaa, S. Messaoudi, L. Giel, Paul W. TI Transonic turbine blade loading calculations using different turbulence models - effects of reflecting and non-reflecting boundary conditions SO APPLIED THERMAL ENGINEERING LA English DT Article; Proceedings Paper CT Conference of the Italian-Thermotechnic-Association (ATI) CY MAY 14-17, 2006 CL Milan, ITALY SP ATI DE transonic gas turbine; turbulent conditions; RBC and NRBC effects ID CASCADE AB The objective of this study is to simulate the transonic gas turbine blade-to-blade compressible fluid flow. We are interested mainly in the determination of the pressure distribution around the blade. The particular blade architecture makes these simulations more complex due to the variety of phenomena induced by this flow. Our study is based on the experiment performed by Giel and colleagues. Tests were conducted in a linear cascade at the NASA Glenn Research Center. The test article was a turbine rotor with design flow turning of 136 degrees and an axial chord of 12.7 cm. Simulations were performed on an irregular quadratic structured grid with the FLUENT software package which solves the Navier-Stokes equations by using finite volume methods. Two-dimensional stationary numerical simulations were made under turbulent conditions allowing us to compare the characteristic flow effects of Reflecting Boundary Conditions (RBC) and Non-Reflecting Boundary Conditions (NRBC) newly implemented in FLUENT 6.0. Many simulations were made to compare different turbulence models: a one equation model (Spalart-Allmaras), several two-equation models (k-epsilon, RNG k-epsilon, Realizable k-epsilon, SST k-omega), and a Reynolds-stress model (RSM). Also examined were the effects of the inlet turbulence intensities (0.25% and 7%), the exit Mach numbers (1.0 and 1.3) and the inlet Reynolds numbers (0.5 x 10(6) and I X 10(6)). The results obtained show a good correlation with the experiment. (c) 2006 Elsevier Ltd. All rights reserved. C1 Batna Univ, Fac Sci, Dept Phys, Batna 05000, Algeria. Batna Univ, Fac Engn Sci, Dept Mech, Batna 05000, Algeria. QSS Grp Inc, NASA Glenn Res Ctr, Cleveland, OH 44135 USA. RP Djouimaa, S (reprint author), Batna Univ, Fac Sci, Dept Phys, Ave Chahid Boukhlouf Med, Batna 05000, Algeria. EM sihemdjouimaa@univ-batna.dz NR 24 TC 9 Z9 11 U1 1 U2 7 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1359-4311 J9 APPL THERM ENG JI Appl. Therm. Eng. PD MAR PY 2007 VL 27 IS 4 BP 779 EP 787 DI 10.1016/j.applthermaleng.2006.10.018 PG 9 WC Thermodynamics; Energy & Fuels; Engineering, Mechanical; Mechanics SC Thermodynamics; Energy & Fuels; Engineering; Mechanics GA 109RI UT WOS:000242325800013 ER PT J AU Watson, AM Stapelfeldt, KR AF Watson, Alan M. Stapelfeldt, Karl R. TI Asymmetry and variability in the HH 30 circumstellar disk SO ASTRONOMICAL JOURNAL LA English DT Article DE accretion, accretion disks; circumstellar matter; stars : individual (HH 30); stars : pre-main-sequence ID T-TAURI STARS; HUBBLE-SPACE-TELESCOPE; HH 30; AA TAURI; ACCRETION; IMAGES; PERFORMANCE; CALIBRATION; ALIGNMENT; OBJECTS AB We consider optical and near-infrared images of the edge-on disk surrounding the young stellar object HH 30 taken with the Hubble Space Telescope at 18 epochs from 1994 to 2005. These images allow us to study asymmetry and variability in the disk. The lateral brightness asymmetry in the upper nebula, first seen to strongly vary in 1998, continues to show significant variability throughout the period of our observations. The lateral asymmetry is not uniformly distributed between both sides of the disk; the upper nebula appears brighter on its north-northwest side at 12 epochs, nearly symmetric at four epochs, and brighter on its east-southeast side at only two epochs. This and other evidence indicate that the lateral asymmetry has both static and variable components. The lateral asymmetry shares the overall continuum color of the nebula and is weaker in emission lines than in the continuum. We have searched for periodicity in the sense of the lateral asymmetry. While some possible periods can be excluded, there is no convincing evidence for any specific period. We also consider the lower counternebula. It is as a whole less variable than the upper nebula and shows no significant lateral variability. We discuss several possible mechanisms that might explain these phenomena. Periodic illumination or shadowing models remain viable at periods less than 1 yr, but further observations are required to firmly establish them. C1 Univ Nacl Autonoma Mexico, Ctr Radioastron & Astrofis, Morelia, Michoacan, Mexico. CALTECH, Jet Propuls Lab, Pasadena, CA 91125 USA. RP Watson, AM (reprint author), Univ Nacl Autonoma Mexico, Ctr Radioastron & Astrofis, Morelia, Michoacan, Mexico. RI Stapelfeldt, Karl/D-2721-2012 NR 37 TC 34 Z9 34 U1 0 U2 3 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-6256 J9 ASTRON J JI Astron. J. PD MAR PY 2007 VL 133 IS 3 BP 845 EP 861 DI 10.1086/510455 PG 17 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 142GE UT WOS:000244636600005 ER PT J AU Weigelt, G Kraus, S Driebe, T Petrov, RG Hofmann, KH Millour, F Chesneau, O Schertl, D Malbet, F Hillier, DJ Gull, T Davidson, K de Souza, AD Antonelli, P Beckmann, U Bresson, Y Chelli, A Dugue, M Duvert, G Gennari, S Gluck, L Kern, P Lagarde, S Le Coarer, E Lisi, F Perraut, K Puget, P Rantakyro, F Robbe-Dubois, S Roussel, A Tatulli, E Zins, G Accardo, M Acke, B Agabi, K Altariba, E Arezki, B Aristidi, E Baffa, C Behrend, J Blocker, T Bonhomme, S Busoni, S Cassaing, F Clausse, JM Colin, J Connot, C Delboulbe, A Feautrier, P Ferruzzi, D Forveille, T Fossat, E Foy, R Fraix-Burnet, D Gallardo, A Giani, E Gil, C Glentzlin, A Heiden, M Heininger, M Utrera, OH Kamm, D Kiekebusch, M Le Contel, D Le Contel, JM Lesourd, T Lopez, B Lopez, M Magnard, Y Marconi, A Mars, G Martinot-Lagarde, G Mathias, P Mege, P Monin, JL Mouillet, D Mourard, D Nussbaum, E Ohnaka, K Pacheco, J Perrier, C Rabbia, Y Rebattu, S Reynaud, F Richichi, A Robini, A Sacchettini, M Scholler, M Solscheid, W Spang, A Stee, P Stefanini, P Tallon, M Tallon-Bosc, I Tasso, D Testi, L Vakili, F von der Luhe, O Valtier, JC Vannier, M Ventura, N Weis, K Wittkowski, M AF Weigelt, G. Kraus, S. Driebe, T. Petrov, R. G. Hofmann, K. -H. Millour, F. Chesneau, O. Schertl, D. Malbet, F. Hillier, D. J. Gull, T. Davidson, K. de Souza, A. Domiciano Antonelli, P. Beckmann, U. Bresson, Y. Chelli, A. Dugue, M. Duvert, G. Gennari, S. Glueck, L. Kern, P. Lagarde, S. Le Coarer, E. Lisi, F. Perraut, K. Puget, P. Rantakyro, F. Robbe-Dubois, S. Roussel, A. Tatulli, E. Zins, G. Accardo, M. Acke, B. Agabi, K. Altariba, E. Arezki, B. Aristidi, E. Baffa, C. Behrend, J. Bloecker, T. Bonhomme, S. Busoni, S. Cassaing, F. Clausse, J. -M. Colin, J. Connot, C. Delboulbe, A. Feautrier, P. Ferruzzi, D. Forveille, T. Fossat, E. Foy, R. Fraix-Burnet, D. Gallardo, A. Giani, E. Gil, C. Glentzlin, A. Heiden, M. Heininger, M. Utrera, O. Hernandez Kamm, D. Kiekebusch, M. Le Contel, D. Le Contel, J. -M. Lesourd, T. Lopez, B. Lopez, M. Magnard, Y. Marconi, A. Mars, G. Martinot-Lagarde, G. Mathias, P. Mege, P. Monin, J. -L. Mouillet, D. Mourard, D. Nussbaum, E. Ohnaka, K. Pacheco, J. Perrier, C. Rabbia, Y. Rebattu, S. Reynaud, F. Richichi, A. Robini, A. Sacchettini, M. Schoeller, M. Solscheid, W. Spang, A. Stee, P. Stefanini, P. Tallon, M. Tallon-Bosc, I. Tasso, D. Testi, L. Vakili, F. von der Luehe, O. Valtier, J. -C. Vannier, M. Ventura, N. Weis, K. Wittkowski, M. TI Near-infrared interferometry of eta Carinae with spectral resolutions of 1 500 and 12 000 using AMBER/VLTI SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE stars : individual : eta Carinae; stars : mass-loss, emission-line Be, circumstellar matter; winds, outflows; infrared : stars; techniques : interferometric ID TELESCOPE IMAGING SPECTROGRAPH; GALACTIC CEPHEIDS; BINARY HYPOTHESIS; HOMUNCULUS-NEBULA; STELLAR WIND; SPECTROSCOPY; EVENT; SHAPE; VARIABILITY; ENVIRONMENT AB Aims. We present the first NIR spectro-interferometry of the LBV eta Carinae. The observations were performed with the AMBER instrument of the ESO Very Large Telescope Interferometer (VLTI) using baselines from 42 to 89 m. The aim of this work is to study the wavelength dependence of eta Car's optically thick wind region with a high spatial resolution of 5 mas (11 AU) and high spectral resolution. Methods. The observations were carried out with three 8.2 m Unit Telescopes in the K-band. The raw data are spectrally dispersed interferograms obtained with spectral resolutions of 1500 (MR-K mode) and 12 000 (HR-K mode). The MR-K observations were performed in the wavelength range around both the He I 2.059 mu m and the Br gamma 2.166 mu m emission lines, the HR-K observations only in the Br gamma line region. Results. The spectrally dispersed AMBER interferograms allow the investigation of the wavelength dependence of the visibility, differential phase, and closure phase of eta Car. In the K-band continuum, a diameter of 4.0 +/- 0.2 mas (Gaussian FWHM, fit range 28-89 m baseline length) was measured for eta Car's optically thick wind region. If we fit Hillier et al. (2001, ApJ, 553, 837) model visibilities to the observed AMBER visibilities, we obtain 50% encircled-energy diameters of 4.2, 6.5 and 9.6 mas in the 2.17 mu m continuum, the He I, and the Br gamma emission lines, respectively. In the continuum near the Br gamma line, an elongation along a position angle of 120 degrees +/- 15 degrees was found, consistent with previous VINCI/VLTI measurements by van Boekel et al. (2003, A&A, 410, L37). We compare the measured visibilities with predictions of the radiative transfer model of Hillier et al. ( 2001), finding good agreement. Furthermore, we discuss the detectability of the hypothetical hot binary companion. For the interpretation of the non-zero differential and closure phases measured within the Br gamma line, we present a simple geometric model of an inclined, latitude-dependent wind zone. Our observations support theoretical models of anisotropic winds from fast-rotating, luminous hot stars with enhanced high-velocity mass loss near the polar regions. C1 Max Planck Inst Radioastron, D-53121 Bonn, Germany. Univ Nice, CNRS, UMR 6525, Astrophys Lab, F-06108 Nice 2, France. Univ Grenoble 1, CNRS, UMR 5571, Astrophys Lab, F-38041 Grenoble 9, France. Observ Cote Azur, CNRS, UMR 6203, Lab Gemini, F-06304 Nice 4, France. Osserv Astrofis Arcetri, Ist Nazl Astrofis, INAF, I-50125 Florence, Italy. Univ Pittsburgh, Dept Phys & Astron, Pittsburgh, PA 15260 USA. Goddard Space Flight Ctr, Lab Extraterr Planets & Stellar Astrophys, Greenbelt, MD 20771 USA. Univ Minnesota, Sch Phys & Astron, Minneapolis, MN 55455 USA. European So Observ, Santiago 19, Chile. Off Natl Etud & Rech Aerosp, DOTA, F-92322 Chatillon, France. Univ Lyon 1, CNRS, UMR 5574, Ctr Rech Astron Lyon, F-69561 St Genis Laval, France. CNRS, UPS 855, Div Tech INSU, F-92195 Meudon, France. Univ Limoges, CNRS, UMR 6615, IRCOM, F-87060 Limoges, France. European So Observ, D-85748 Garching, Germany. Kiepenheuer Inst Sonnenphys, D-79104 Freiberg, Germany. Katholieke Univ Leuven, Inst Sterrenkunde, B-3001 Louvain, Belgium. Univ Porto, Ctr Astrofis, P-4150762 Oporto, Portugal. Univ Toulouse 3, CNRS, UMR 5572, Lab Astrophys Toulouse, F-65008 Tarbes, France. Univ Chile, Dept Astron, Santiago, Chile. Ruhr Univ Bochum, Astron Inst, D-44780 Bochum, Germany. RP Weigelt, G (reprint author), Max Planck Inst Radioastron, Hugel 69, D-53121 Bonn, Germany. RI Tallon, Michel/C-4078-2009; Gull, Theodore/D-2753-2012; Marconi, Alessandro/C-5880-2009 OI Gull, Theodore/0000-0002-6851-5380; Marconi, Alessandro/0000-0002-9889-4238 NR 54 TC 69 Z9 69 U1 1 U2 3 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD MAR PY 2007 VL 464 IS 1 BP 87 EP 106 DI 10.1051/0004-6361:20065577 PG 20 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 139BV UT WOS:000244407900010 ER PT J AU Krips, M Eckart, A Neri, R Bertram, T Straubmeier, C Fischer, S Staguhn, JG Vogel, SN AF Krips, M. Eckart, A. Neri, R. Bertram, T. Straubmeier, C. Fischer, S. Staguhn, J. G. Vogel, S. N. TI Barred CO emission in HE 1029-1831 SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE galaxies : active; galaxies : kinematics and dynamics; galaxies : individual : HE 1029-1831; radio lines : galaxies; galaxies : Seyfert ID MOLECULAR GAS; GALAXIES NUGA; INFRARED GALAXIES; NUCLEI; AGN AB We present CO(1-0) and CO(2-1) line emission maps of the barred spiral active galaxy HE 1029-1831 (z = 0.0403) obtained with the IRAM Plateau de Bure Interferometer (PdBI) and in part by the Berkeley-Illinois-Maryland Association (BIMA) observatory. The CO emission is well associated with the optical bar and extended along it. The FWHM of the CO emission is estimated to be similar to(6 +/- 2) kpc. The CO emission shows a strong velocity gradient along the minor axis of the bar (PA = 90 degrees). The molecular gas mass is estimated to be similar to 1.2 x 10(10) M-circle dot which indicates a very gas rich host galaxy. Most of the molecular gas appears to be subthermally excited and cold but we also find weak evidence for a warmer and/or denser gas component at the southern part of the bar emission, about similar to 4 kpc from the galactic nucleus. C1 Univ Cologne, Inst Phys 1, D-50937 Cologne, Germany. Harvard Smithsonian Ctr Astrophys, SMA Project, Hilo, HI 96720 USA. Inst Radio Astron Millimetr, F-38406 St Martin Dheres, France. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Maryland, College Pk, MD 20742 USA. RP Krips, M (reprint author), Univ Cologne, Inst Phys 1, Zulpicher Str 77, D-50937 Cologne, Germany. EM mkrips@cfa.harvard.edu NR 17 TC 8 Z9 8 U1 0 U2 0 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD MAR PY 2007 VL 464 IS 1 BP 187 EP 191 DI 10.1051/0004-6361:20065832 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 139BV UT WOS:000244407900019 ER PT J AU Poelman, DR Spaans, M Tielens, AGGM AF Poelman, D. R. Spaans, M. Tielens, A. G. G. M. TI The interpretation of water emission from dense interstellar clouds SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE ISM : molecules; radiative transfer; ISM : dust, extinction ID ASTRONOMY-SATELLITE OBSERVATIONS; PHOTON-DOMINATED REGION; COLLISIONAL EXCITATION; MOLECULAR CLOUDS; H2O; ATMOSPHERE; ABUNDANCE; CHEMISTRY; OXYGEN; VAPOR AB Context. Existing SWAS observations and future HIFI/Herschel data require a clear sense of the information content of water emission and absorption lines. Aims. We investigate whether the ground- state transition of ortho- H2O ( 1(10) -> 1(01)) at 557 GHz can be used to measure the column density throughout an interstellar cloud. Methods. We make use of a multi- zone escape probability code suitable for treating molecular line emission. Results. For low abundances, i. e., X( H2O) <= 10(-9), the intensity of the 1(10) -> 1(01) transition scales with the total column density of H2. However, this relationship breaks down with increasing abundance, i. e., optical depth, due to line trapping and - for T-dust greater than or similar to 25 K, X(H2O) less than or similar to 10- 8 and n similar to 10(4) cm(-3) - absorption of the dust continuum. Conclusions. An observed decline in intensity per column density, expected if H2O is a surface tracer, does not necessarily mean that the water is absent in the gas phase at large column densities, but can be caused by line trapping and subsequent collisional deexcitation. To determine the amount of water vapor in the interstellar medium, multiple line measurements of optically thin transitions are needed to disentangle radiative transfer and local excitation effects. C1 Univ Groningen, Kapteyn Astron Inst, NL-9700 AV Groningen, Netherlands. Univ Groningen, SRON Netherlands Inst Space Res, NL-9747 AD Groningen, Netherlands. NASA Ames Res Ctr, Moffett Field, CA 94035 USA. RP Poelman, DR (reprint author), Univ Groningen, Kapteyn Astron Inst, POB 800, NL-9700 AV Groningen, Netherlands. EM D.R.Poelman@astro.rug.nl NR 20 TC 10 Z9 11 U1 0 U2 1 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD MAR PY 2007 VL 464 IS 3 BP 1023 EP 1027 DI 10.1051/0004-6361:20066184 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 143WJ UT WOS:000244756800034 ER PT J AU Sullivan, I Cooray, A Chary, RR Bock, JJ Brodwin, M Brown, MJI Dey, A Dickinson, M Eisenhardt, P Ferguson, HC Giavalisco, M Keating, B Lange, A Mobasher, B Reach, WT Stern, D Wright, EL AF Sullivan, Ian Cooray, Asantha Chary, Ranga-Ram Bock, James J. Brodwin, Mark Brown, Michael J. I. Dey, Arjun Dickinson, Mark Eisenhardt, Peter Ferguson, Henry C. Giavalisco, Mauro Keating, Brian Lange, Andrew Mobasher, Bahram Reach, William T. Stern, Daniel Wright, Edward L. TI Clustering of the IR background light with Spitzer: Contribution from resolved sources SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmology : theory; diffuse radiation; infrared : galaxies; large-scale structure of universe ID LYMAN BREAK GALAXIES; ARRAY CAMERA IRAC; LUMINOSITY FUNCTIONS; SPACE-TELESCOPE; LARGE-SCALE; PHOTOMETRIC REDSHIFTS; POPULATION-III; SHALLOW SURVEY; STARS; EVOLUTION AB We describe the angular power spectrum of resolved sources at 3.6 mu m (L band) in Spitzer imaging data of the GOODS HDF-N, the GOODS CDF-S, and the NDWFS Bootes field in several source magnitude bins. We also measure angular power spectra of resolved sources in the Bootes field at K-s and J bands using ground-based IR imaging data. In the three bands, J, K-s, and L, we detect the clustering of galaxies on top of the shot-noise power spectrum at multipoles between l similar to 10(2) and 10(5). The angular power spectra range from the large, linear scales to small, nonlinear scales of galaxy clustering, and in some magnitude ranges show departure from a power-law clustering spectrum. We consider a halo model to describe clustering measurements and to establish the halo occupation number parameters of IR bright galaxies at redshifts around one. The typical halo mass scale at which two or more IR galaxies with L-band Vega magnitude between 17 and 19 are found in the same halo is between 9 x 10(11) and 7 x 10(12) M-circle dot at the 1 sigma confidence level; this is consistent with the previous halo mass estimates for bright, red galaxies at z similar to 1. We also extend our clustering results and completeness-corrected faint-source number counts in GOODS fields to understand the underlying nature of unresolved sources responsible for IR background (IRB) anisotropies that were detected in deep Spitzer images. While these unresolved fluctuations were measured at subarcminute angular scales, if a high-redshift diffuse component associated with first galaxies exists in the IRB, then it's clustering properties are best studied with shallow, wide-field images that allow a measurement of the clustering spectrum from a few degrees to arcminute angular scales. C1 CALTECH, Div Phys Math & Astron, Pasadena, CA 91125 USA. Univ Calif Irvine, Dept Phys & Astron, Ctr Cosmol, Irvine, CA USA. CALTECH, Jet Prop Lab, Pasadena, CA USA. Princeton Univ Observ, Princeton, NJ 08544 USA. Natl Opt Astron Observ, Tucson, AZ 85726 USA. Space Telescope Sci Inst, Baltimore, MD 21218 USA. Univ Calif San Diego, La Jolla, CA 92093 USA. CALTECH, Spitzer Sci Ctr, Pasadena, CA 91125 USA. Univ Calif Los Angeles, Los Angeles, CA USA. RP Sullivan, I (reprint author), CALTECH, Div Phys Math & Astron, Pasadena, CA 91125 USA. EM acooray@uci.edu RI Brown, Michael/B-1181-2015; OI Brown, Michael/0000-0002-1207-9137; Reach, William/0000-0001-8362-4094 NR 60 TC 18 Z9 18 U1 0 U2 3 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X EI 1538-4357 J9 ASTROPHYS J JI Astrophys. J. PD MAR 1 PY 2007 VL 657 IS 1 BP 37 EP 50 DI 10.1086/511293 PN 1 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 142FR UT WOS:000244635300004 ER PT J AU Sato, G Yamazaki, R Ioka, K Sakamoto, T Takahashi, T Nakazawa, K Nakamura, T Toma, K Hullinger, D Tashiro, M Parsons, AM Krimm, HA Barthelmy, SD Gehrels, N Burrows, DN O'Brien, PT Osborne, JP Chincarini, G Lamb, DQ AF Sato, G. Yamazaki, R. Ioka, K. Sakamoto, T. Takahashi, T. Nakazawa, K. Nakamura, T. Toma, K. Hullinger, D. Tashiro, M. Parsons, A. M. Krimm, H. A. Barthelmy, S. D. Gehrels, N. Burrows, D. N. O'Brien, P. T. Osborne, J. P. Chincarini, G. Lamb, D. Q. TI Swift discovery of gamma-ray bursts without a jet break feature in their X-ray afterglows SO ASTROPHYSICAL JOURNAL LA English DT Article DE gamma rays : bursts; ISM : jets and outflows; radiation mechanisms : nonthermal ID THEORETICAL IMPLICATIONS; LIGHT CURVES; PEAK-ENERGY; XRF 050416A; ENERGETICS; TELESCOPE; EMISSION; SPECTRA; GRB-050401; CATALOG AB We analyze Swift gamma-ray bursts (GRBs) and X-ray afterglows for three GRBs with spectroscopic redshift determinations: GRB 050401, XRF 050416a, and GRB 050525a. We find that the relation between spectral peak energy and isotropic energy of prompt emissions (the Amati relation) is consistent with that for the bursts observed in the pre-Swift era. However, we find that the X-ray afterglow light curves, which extend up to 10-70 days, show no sign of the jet break that is expected in the standard framework of collimated outflows. We do so by showing that none of the X-ray afterglow light curves in our sample satisfy the relation between the spectral and temporal indices that is predicted for the phase after jet break. The jet break time can be predicted by inverting the tight empirical relation between the peak energy of the spectrum and the collimation-corrected energy of the prompt emission (the Ghirlanda relation). We find that there are no temporal breaks within the predicted time intervals in X-ray band. This requires either that the Ghirlanda relation has a larger scatter than previously thought, that the temporal break in X-rays is masked by some additional source of X-ray emission, or that it does not happen for some unknown reason. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. JAXA, Inst Space & Astron Sci, Kanagawa, Japan. Hiroshima Univ, Dept Phys, Hiroshima 730, Japan. Kyoto Univ, Dept Phys, Kyoto 606, Japan. Oak Ridge Associated Univ, Oak Ridge, TN USA. Univ Tokyo, Dept Phys, Bunkyo Ku, Tokyo 106, Japan. Brigham Young Univ, Dept Phys, Rexburg, ID USA. Univ Maryland, Dept Phys, College Pk, MD 20742 USA. Saitama Univ, Dept Phys, Saitama, Japan. Univ Space Res Assoc, Columbia, MD USA. Penn State Univ, Dept Phys, University Pk, PA 16802 USA. Univ Leicester, Dept Phys & Astron, Leicester LE1 7RH, Leics, England. Univ Milan, Dipartimento Fis, I-20122 Milan, Italy. INAF, Osservatorio Astron Brera, Merate, LC, Italy. Univ Chicago, Dept Astron & Astrophys, Chicago, IL 60637 USA. RP Sato, G (reprint author), NASA, Goddard Space Flight Ctr, Code 661, Greenbelt, MD 20771 USA. RI Barthelmy, Scott/D-2943-2012; Gehrels, Neil/D-2971-2012; Parsons, Ann/I-6604-2012; Tashiro, Makoto/J-4562-2012 NR 48 TC 38 Z9 38 U1 0 U2 2 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X EI 1538-4357 J9 ASTROPHYS J JI Astrophys. J. PD MAR 1 PY 2007 VL 657 IS 1 BP 359 EP 366 DI 10.1086/510610 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 142FR UT WOS:000244635300030 ER PT J AU Fukumura, K Takahashi, M Tsuruta, S AF Fukumura, Keigo Takahashi, Masaaki Tsuruta, Sachiko TI Magnetohydrodynamic shocks in nonequatorial plasma flows around a black hole SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; black hole physics; galaxies : active; MHD; relativity; shock waves; stars : coronae ID MAGNETICALLY DRIVEN ACCRETION; ROTATING COMPACT OBJECTS; K-EMISSION-LINE; X-RAY-SPECTRA; KERR GEOMETRY; JET FORMATION; HYDROMAGNETIC FLOWS; ASTROPHYSICAL JETS; MAGNETOSPHERE; SIMULATIONS AB We study magnetohydrodynamic (MHD) standing shocks in inflowing plasmas in a black hole magnetosphere. Fast and intermediate shock formation is explored in Schwarzschild and Kerr geometry to illustrate general relativistic effects. We find that nonequatorial standing MHD shocks are physically possible, creating a very hot plasma region close to the event horizon. Shocked downstream plasmas can be heated or magnetized depending on the values of various magnetic field-aligned parameters. Then we may expect high-energy thermal/nonthermal emissions from the shocked region. We present the properties of nonequatorial MHD shocks and discuss the shocked plasma region in the black hole magnetosphere. We also investigate the effects of the poloidal magnetic field and black hole spin on the properties of shocks and show that both effects can modify the distribution of the shock front and shock strength. We find for strong MHD shock formation that fast rotating magnetic fields are necessary. The physics of nonequatorial MHD shocks in the black hole magnetosphere could be very important when we construct the central engine model of various astrophysical phenomena. C1 Montana State Univ, Dept Phys, Bozeman, MT 59717 USA. Aichi Univ Educ, Dept Phys & Astron, Kariya, Aichi 448, Japan. RP Fukumura, K (reprint author), NASA, Goddard Space Flight Ctr, Code 661, Greenbelt, MD 20771 USA. EM fukumura@physics.montana.edu; takahasi@phyas.aichi-edu.ac.jp; uphst@gemini.msu.montana.edu NR 49 TC 12 Z9 12 U1 0 U2 3 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAR 1 PY 2007 VL 657 IS 1 BP 415 EP 427 DI 10.1086/510660 PN 1 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 142FR UT WOS:000244635300036 ER PT J AU Lommen, A Donovan, J Gwinn, C Arzoumanian, Z Harding, A Strickman, M Dodson, R McCulloch, P Moffett, D AF Lommen, A. Donovan, J. Gwinn, C. Arzoumanian, Z. Harding, A. Strickman, M. Dodson, R. McCulloch, P. Moffett, D. TI Correlation between X-ray light-curve shape and radio arrival time in the Vela pulsar SO ASTROPHYSICAL JOURNAL LA English DT Article DE pulsars : individual (Vela) ID GAMMA-RAY; RESOLUTION OBSERVATIONS; OPTICAL-EMISSION; CRAB PULSAR; PROFILE; PHASE; MODEL AB We report the results of simultaneous observations of the Vela pulsar in X-rays and radio from the RXTE satellite and the Mount Pleasant Radio Observatory in Tasmania. We sought correlations between Vela's X-ray emission and radio arrival times on a pulse-by-pulse basis. At a confidence level of 99.8% we have found significantly higher flux density in Vela's main X-ray peak during radio pulses that arrived early. This excess flux shifts to the "trough'' following the second X-ray peak during radio pulses that arrive later. Our results suggest that the mechanism producing the radio pulses is intimately connected to the mechanism producing X-rays. Current models using resonant absorption of radio emission in the outer magnetosphere as a cause of the X-ray emission are explored as a possible explanation for the correlation. C1 Franklin & Marshall Coll, Dept Phys & Astron, Lancaster, PA 17604 USA. Columbia Univ, Dept Astron, New York, NY 10027 USA. Univ Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USA. NASA, Goddard Space Flight Ctr, Astrophys Sci Div, Greenbelt, MD 20771 USA. Univ Space Res Assoc, Columbia, MD USA. USN, Res Lab, Washington, DC 20350 USA. Natl Astron Observ, Madrid, Spain. Univ Tasmania, Sch Math & Phys, Hobart, Tas 7001, Australia. Furman Univ, Dept Phys, Greenville, SC 29613 USA. RP Lommen, A (reprint author), Franklin & Marshall Coll, Dept Phys & Astron, Lancaster, PA 17604 USA. NR 20 TC 10 Z9 10 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAR 1 PY 2007 VL 657 IS 1 BP 436 EP 440 DI 10.1086/510797 PN 1 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 142FR UT WOS:000244635300038 ER PT J AU Rappazzo, AF Velli, M Einaudi, G Dahlburg, RB AF Rappazzo, A. F. Velli, M. Einaudi, G. Dahlburg, R. B. TI Coronal heating, weak MHD turbulence, and scaling laws SO ASTROPHYSICAL JOURNAL LA English DT Article DE MHD; Sun : corona; Sun : magnetic fields; turbulence ID MAGNETOHYDRODYNAMIC TURBULENCE; SOLAR CORONA; MAGNETIC-FIELD; STATISTICS; NANOFLARES; SPECTRUM; LOOPS AB Long-time high-resolution simulations of the dynamics of a coronal loop in Cartesian geometry are carried out, within the framework of reduced magnetohydrodynamics (RMHD), to understand coronal heating driven by the motion of field lines anchored in the photosphere. We unambiguously identify MHD anisotropic turbulence as the physical mechanism responsible for the transport of energy from the large scales, where energy is injected by photospheric motions, to the small scales, where it is dissipated. As the loop parameters vary, different regimes of turbulence develop: strong turbulence is found for weak axial magnetic fields and long loops, leading to Kolmogorovlike spectra in the perpendicular direction, while weaker and weaker regimes (steeper spectral slopes of total energy) are found for strong axial magnetic fields and short loops. As a consequence we predict that the scaling of the heating rate with axial magnetic field intensity, which depends on the spectral index of total energy for given B-0 loop parameters, must vary from B-0(3/2) for weak fields to B-0(2) for strong fields at a given aspect ratio. The predicted heating rate is within the lower range of observed active region and quiet-Sun coronal energy losses. C1 Univ Pisa, Dipartimento Fis E Fermi, Pisa, Italy. Jet Prop Lab, Pasadena, CA 91109 USA. Univ Florence, Dipartimento Astron & Sci Spazio, Florence, Italy. USN, Res Lab, Lab Computat Phys & Fluid Dynam, Washington, DC 20375 USA. RP Rappazzo, AF (reprint author), Univ Pisa, Dipartimento Fis E Fermi, Pisa, Italy. EM rappazzo@jpl.nasa.gov NR 22 TC 74 Z9 74 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD MAR 1 PY 2007 VL 657 IS 1 BP L47 EP L51 DI 10.1086/512975 PN 2 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 142FU UT WOS:000244635600012 ER PT J AU Sterling, NC Dinerstein, HL Kallman, TR AF Sterling, N. C. Dinerstein, Harriet L. Kallman, T. R. TI The abundances of light neutron-capture elements in planetary nebulae. I. Photoionization modeling and ionization corrections SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article DE atomic data; infrared : general; nuclear reactions, nucleosynthesis, abundances; planetary nebulae : general; stars : AGB and post-AGB ID ASYMPTOTIC GIANT BRANCH; EFFECTIVE COLLISION STRENGTHS; OPTICAL RECOMBINATION LINES; S-PROCESS; DIELECTRONIC RECOMBINATION; RATE COEFFICIENTS; NGC 7027; TRANSITION-PROBABILITIES; RADIATIVE RECOMBINATION; LABORATORY MEASUREMENTS AB We have conducted a large-scale survey of 120 planetary nebulae (PNe) to search for the near-infrared emission lines [Kr III] 2.199 mu m and [Se IV] 2.287 mu m. The neutron (n)-capture elements Se and Kr may be enriched in a PN if its progenitor star experienced s-process nucleosynthesis and third dredge-up. In order to determine Se and Kr abundances, we have added these elements to the atomic databases of the photoionization codes Cloudy and XSTAR, which we use to derive ionization correction factors (ICFs) to account for the abundances of unobserved Se and Kr ions. However, much of the atomic data governing the ionization balance of these two elements are unknown, and have been approximated from general principles. We find that uncertainties in the atomic data can lead to errors approaching 0.3 dex in the derived Se abundances and up to 0.2-0.25 dex for Kr. To reduce the uncertainties in the Kr ionization balance stemming from the approximate atomic data, we have modeled 10 bright PNe in our sample, selected because they exhibit emission lines from multiple Kr ions in their optical and near-infrared spectra. We have empirically adjusted the uncertain Kr atomic data until the observed line intensities of the various Kr ions are adequately reproduced by our models. Using the adjusted Kr atomic data, we have computed a grid of models over a wide range of physical parameters ( central star temperature, nebular density, and ionization parameter) and derived formulae that can be used to compute Se and Kr ICFs. In the second paper of this series, we will apply these ICFs to our full sample of 120 PNe, which comprises the first large-scale survey of n-capture elements in PNe. C1 Univ Texas, Dept Astron, Austin, TX 78712 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. EM sterling@astro.as.utexas.edu; harriet@astro.as.utexas.edu; tim@milkyway.gsfc.nasa.gov NR 97 TC 42 Z9 42 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0067-0049 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD MAR PY 2007 VL 169 IS 1 BP 37 EP 61 DI 10.1086/511031 PG 25 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 142FY UT WOS:000244636000004 ER PT J AU Kalemci, E Boggs, SE Kouveliotou, C Finger, M Baring, MG AF Kalemci, E. Boggs, S. E. Kouveliotou, C. Finger, M. Baring, M. G. TI Search for polarization from the prompt gamma-ray emission of GRB 041219a with SPI on INTEGRAL SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article DE gamma rays : bursts; gamma rays : observations; instrumentation : polarimeters methods :; data analysis; polarization; techniques : polarimetric ID SELF-COMPTON EMISSION; BLAST-WAVE MODEL; BURST AFTERGLOWS; SYNCHROTRON; SPECTROMETER; POLARIMETRY; GRB-021206; ASTRONOMY; SPECTRA; STELLAR AB Measuring the polarization of the prompt gamma-ray emission from gamma-ray bursts (GRBs) can significantly improve our understanding of both the GRB emission mechanisms as well as the underlying engine driving the explosion. We searched for polarization in the prompt gamma-ray emission of GRB 041219a with the SPI instrument on INTEGRAL. Using multiple-detector coincidence events in the 100 - 350 keV energy band, our analysis yields a polarization fraction from this GRB of 98% +/- 33%. Statistically, we cannot claim a polarization detection from this source. Moreover, different event selection criteria lead to even less significant polarization fractions, e. g., lower polarization fractions are obtained when higher energies are included in the analysis. We cannot strongly rule out the possibility that the measured modulation is dominated by instrumental systematics. Therefore, SPI observations of GRB 041219a do not significantly constrain GRB models. However, this measurement demonstrates the capability of SPI to measure polarization, as well as the techniques developed for this analysis. C1 Sabanci Univ, TR-34956 Istanbul, Turkey. Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Natl Space & Technol Ctr, Huntsville, AL USA. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. Univ Space Res Assoc, Columbia, MD 21044 USA. Rice Univ, Dept Phys & Astron, Houston, TX 77251 USA. RP Kalemci, E (reprint author), Sabanci Univ, Orhanli Tuzla, TR-34956 Istanbul, Turkey. RI Boggs, Steven/E-4170-2015 OI Boggs, Steven/0000-0001-9567-4224 NR 44 TC 55 Z9 56 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0067-0049 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD MAR PY 2007 VL 169 IS 1 BP 75 EP 82 DI 10.1086/510676 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 142FY UT WOS:000244636000006 ER PT J AU Civerolo, K Hogrefe, C Lynn, B Rosenthal, J Ku, JY Solecki, W Cox, J Small, C Rosenzweig, C Goldberg, R Knowlton, K Kinney, P AF Civerolo, Kevin Hogrefe, Christian Lynn, Barry Rosenthal, Joyce Ku, Jia-Yeong Solecki, William Cox, Jennifer Small, Christopher Rosenzweig, Cynthia Goldberg, Richard Knowlton, Kim Kinney, Patrick TI Estimating the effects of increased urbanization on surface meteorology and ozone concentrations in the New York City metropolitan region SO ATMOSPHERIC ENVIRONMENT LA English DT Article DE models-3/CMAQ; MM5; air pollution meteorology; O-3; land use change ID EASTERN UNITED-STATES; MODEL AEROSOL COMPONENT; CMAQ MODEL; LAND-USE; TROPOSPHERIC OZONE; HYDROLOGY MODEL; CLIMATE-CHANGE; AIR-POLLUTION; URBAN; EMISSIONS AB Land use and pollutant emission changes can have significant impacts on air quality, regional climate, and human health. Here we describe a modeling study aimed at quantifying the potential effects of extensive changes in urban land cover in the New York City (NYC), USA metropolitan region on surface meteorology and ozone (O-3) concentrations. The SLEUTH land-use change model was Used to extrapolate Urban land cover over this region from "present-day" (ca. 1990) conditions to a future year (ca. 2050), and these projections were subsequently integrated into meteorological and air quality simulations. The development of the fUture-year land-use scenario followed the narrative of the "AT' scenario described by the Intergovcrnmental Panel on Climate Change (IPCC), but was restricted to the greater NYC area. The modeling system consists of the Penn State/NCAR MM5 mesoscale meteorological model-, the Sparse Matrix Operator Kernal Emissions processing system; and the US EPA Community Multiscale Air Quality model, and simulations were performed for two 18-day episodes, one near-past and one future. Our results suggest that extensive urban growth in the NYC metropolitan area has the potential to increase afternoon near-surface temperatures by more than 0.6 degrees C and planetary boundary layer (PBL) heights by more than 150m, as well as decrease water vapor mixing ratio by more than 0.6 g kg(-1) across the NYC metropolitan area, with the areal extent of all of these changes generally coinciding with the area of increased urbanization. On the other hand, the impacts of these land use changes on ozone concentrations are more complex. Simulation results O-3 levels by about 1-5 ppb, and episode-maximum 8 h O-3 levels by more than 6 ppb across much of the NYC area. However, spatial patterns of ozone changes are heterogeneous and also indicate the presence of areas with decreasing ozone concentrations. When anthropogenic emissions were increased to be consistent with the extensive urbanization in the greater NYC area, the O-3 levels increased in outer counties of the metropolitan region but decreased in others, including coastal Connecticut and the Long Island Sound area. (c) 2006 Elsevier Ltd. All rights reserved. C1 New York State Dept Environm Conservat, Div Air Resources, Albany, NY USA. SUNY Albany, Atmospher Sci Res Ctr, Albany, NY 12222 USA. NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Columbia Univ, Earth Inst, Ctr Climate Syst Res, New York, NY USA. Columbia Univ, Grad Sch Architecture Planning & Preservat, New York, NY USA. CUNY Hunter Coll, Dept Geog, New York, NY 10021 USA. Columbia Univ, Lamont Doherty Earth Observ, Palisades, NY 10964 USA. Columbia Univ, Mailman Sch Publ Hlth, New York, NY USA. RP Civerolo, K (reprint author), New York State Dept Environm Conservat, Div Air Resources, Albany, NY USA. EM kxcivero@gw.dec.state.ny.us RI Kinney, Patrick/H-7914-2012; OI Civerolo, Kevin/0000-0003-1536-2664 NR 37 TC 65 Z9 69 U1 2 U2 36 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1352-2310 J9 ATMOS ENVIRON JI Atmos. Environ. PD MAR PY 2007 VL 41 IS 9 BP 1803 EP 1818 DI 10.1016/j.atmosenv.2006.10.076 PG 16 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA 141AX UT WOS:000244549600001 ER PT J AU Bhatia, AK Landi, E AF Bhatia, A. K. Landi, E. TI Atomic data and spectral line intensities for Si XI SO ATOMIC DATA AND NUCLEAR DATA TABLES LA English DT Article ID BE-LIKE IONS; HIGHLY IONIZED SILICON; CORONAL DIAGNOSTIC SPECTROMETER; EXTREME-ULTRAVIOLET SPECTRUM; ELECTRON-IMPACT-EXCITATION; COLLISION STRENGTHS; EMISSION-LINES; ISOELECTRONIC SEQUENCE; OSCILLATOR-STRENGTHS; RATE COEFFICIENTS AB Electron impact collision strengths, energy levels, oscillator strengths and spontaneous radiative decay rates are calculated for Si XI. The configurations used are 2s(2), 2s2p, 2p(2), 2131', 2141' and 2s51', with l = s,p and l' = s,p,d giving rise to 92 fine-structure levels in intermediate coupling. Collision strengths are calculated at five incident energies (35, 70, 105, 140, and 175 Ry) in the distorted wave approximation. Excitation rate coefficients are calculated as a function of electron temperature by assuming a Maxwellian electron velocity distribution. Using the excitation rate coefficients and the radiative transition rates of the present work, and R-Matrix results for the 2s(2), 2s2p 2p(2) configurations available in the literature, statistical equilibrium equations for level populations are solved at electron densities covering the range of 10(8)-10(14) cm(-3) at an electron temperature of log T-e(K) = 6.2, corresponding to the maximum abundance of Si X1. Spectral line intensities are calculated, and their diagnostic relevance is discussed. This dataset will be made available in the next version of the CHIANT1 database. (c) 2006 Elsevier Inc. All rights reserved. C1 ARTEP Inc, Columbia, MD 21044 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. USN, Res Lab, Washington, DC 20375 USA. RP Landi, E (reprint author), ARTEP Inc, Columbia, MD 21044 USA. EM landi@poppeo.nrl.navy.mil RI Landi, Enrico/H-4493-2011 NR 40 TC 6 Z9 6 U1 0 U2 0 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0092-640X J9 ATOM DATA NUCL DATA JI Atom. Data Nucl. Data Tables PD MAR PY 2007 VL 93 IS 2 BP 275 EP 353 DI 10.1016/j.adt.2006.06.002 PG 79 WC Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Physics GA 143FA UT WOS:000244704200003 ER PT J AU Sokolowski, W Metcalfe, A Hayashi, S Yahia, L Raymond, J AF Sokolowski, Witold Metcalfe, Annick Hayashi, Shunichi Yahia, L'Hocine Raymond, Jean TI Medical applications of shape memory polymers SO BIOMEDICAL MATERIALS LA English DT Article; Proceedings Paper CT 3rd International Symposium on Advanced Biomaterials and Biomechanics CY APR 03-06, 2005 CL Montreal, CANADA ID BIOMEDICAL APPLICATIONS; MECHANICAL-PROPERTIES; POLYURETHANE; STRESS AB Shape memory polymers (SMP) are lightweight, have a high strain/shape recovery ability, are easy to process, and required properties can be tailored for variety of applications. Recently a number of medical applications have been considered and investigated, especially for polyurethane-based SMP. SMP materials were found to be biocompatible, non-toxic and non-mutagenic. The glass transition temperature (Tg) can be tailored for shape restoration/self-deployment of clinical devices when inserted in the human body. Newly developed SMP foams, together with cold hibernated elastic memory (CHEM) processing, further broaden their potential biomedical applications. Polyurethane-based SMP are described here and major advantages are identified over other medical materials. Some SMP applications are already used in a clinical setting, whereas others are still in development. Lately, several important applications are being considered for CHEM foams as self-deployable vascular and coronary devices. One example is the endovascular treatment of aneurysms. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. CHUM Res Ctr, Intervent Neuroradiol Lab, Notre Dame Hosp, Montreal, PQ H2L 4M1, Canada. Ecole Polytech, Biomed Engn Inst, Montreal, PQ H3C 3A7, Canada. RP Sokolowski, W (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM Witold.M.Sokolowski@jpl.nasa.gov RI Raymond, Jean/D-3940-2011 NR 26 TC 125 Z9 126 U1 7 U2 56 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 1748-6041 J9 BIOMED MATER JI Biomed. Mater. PD MAR PY 2007 VL 2 IS 1 BP S23 EP S27 DI 10.1088/1748-6041/2/1/S04 PG 5 WC Engineering, Biomedical; Materials Science, Biomaterials SC Engineering; Materials Science GA 212LH UT WOS:000249597300005 PM 18458416 ER PT J AU Benz, GW Hoffmayer, ER Driggers, WB Allen, D Bishop, LE Brown, DA AF Benz, George W. Hoffmayer, Eric R. Driggers, William B., III Allen, Dan Bishop, Lougan E. Brown, David A. TI First record of a sleeper shark in the western Gulf of Mexico and comments on taxonomic uncertainty within Somniosus (Somniosus) SO BULLETIN OF MARINE SCIENCE LA English DT Article ID PACIFICUS; SEA AB A sleeper shark, Somniosus (Somniosus) sp., is reported from Alaminos Canyon in the western Gulf of Mexico at a depth of about 2647 m based on observations made using a remotely operated vehicle. This is the first record of a sleeper shark (Somniosus, Somniosidae) from the western Gulf of Mexico and deepest record of any shark from the Gulf of Mexico. Despite claims to the contrary in the literature, no taxonomic character has been identified to date that can be used to unequivocally identify all representatives of Somniosus (Somniosus), and as a result, some species records must be considered dubious. C1 Middle Tennessee State Univ, Dept Biol, Murfreesboro, TN 37132 USA. Univ So Mississippi, Ctr Fisheries Res & Dev, Gulf Coast Res Lab, Ocean Springs, MS 39564 USA. SE Fisheries Sci Ctr, Natl Marine Fisheries Serv, Mississippi Labs, Pascagoula, MS 39568 USA. Chevron Gulf Mexico, Business Unit, Madisonville, LA 70447 USA. Shell EP Europe, NL-9400 HH Assen, Netherlands. RP Benz, GW (reprint author), Middle Tennessee State Univ, Dept Biol, POB 60, Murfreesboro, TN 37132 USA. EM gbenz@mtsu.edu NR 23 TC 6 Z9 7 U1 1 U2 8 PU ROSENSTIEL SCH MAR ATMOS SCI PI MIAMI PA 4600 RICKENBACKER CAUSEWAY, MIAMI, FL 33149 USA SN 0007-4977 J9 B MAR SCI JI Bull. Mar. Sci. PD MAR PY 2007 VL 80 IS 2 BP 343 EP 351 PG 9 WC Marine & Freshwater Biology; Oceanography SC Marine & Freshwater Biology; Oceanography GA 161WE UT WOS:000246046400004 ER PT J AU Chen, SYS Price, JF Zhao, W Donelan, MA Walsh, EJ AF Chen, Shuyi S. Price, James F. Zhao, Wei Donelan, Mark A. Walsh, Edward J. TI The CBLAST-hurricane program and the next-generation fully coupled atmosphere-wave-ocean. Models for hurricane research and prediction SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article ID SEA TRANSFER EXPERIMENT; HIGH WIND CONDITIONS; TROPICAL CYCLONES; SIMULATIONS; INTENSITY; EXCHANGE; IMPACT C1 Univ Miami, Rosenstiel Sch Marine & Atmospher Sci, Miami, FL 33149 USA. Woods Hole Oceanog Inst, Woods Hole, MA 02543 USA. NASA, Goddard Space Flight Ctr, Wallops Isl, VA 23337 USA. RP Chen, SYS (reprint author), Univ Miami, Rosenstiel Sch Marine & Atmospher Sci, Miami, FL 33149 USA. EM schen@rsmas.miami.edu RI Zhao, Wei/K-7846-2012 NR 17 TC 119 Z9 124 U1 2 U2 15 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0003-0007 J9 B AM METEOROL SOC JI Bull. Amer. Meteorol. Soc. PD MAR PY 2007 VL 88 IS 3 BP 311 EP 317 DI 10.1175/BAMS-88-3-311 PG 7 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 156AR UT WOS:000245620700008 ER PT J AU Le Marshall, J Uccellini, L Einaudi, F Colton, M Chang, S Weng, F Uhart, M Lord, S Riishojgaard, LP Phoebus, P Yoe, JG AF Le Marshall, John Uccellini, Louis Einaudi, Franco Colton, Marie Chang, Simon Weng, Fuzhong Uhart, Michael Lord, Stephen Riishojgaard, Lars-Peters Phoebus, Patricia Yoe, James G. TI The joint center for satellite data assimilation SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article ID NUMERICAL WEATHER PREDICTION; RADIATIVE-TRANSFER; PART I; KALMAN FILTER; SOIL-MOISTURE; MODEL; WATER; CLOUDS; SYSTEM; INITIALIZATION AB The joint Center for Satellite Data Assimilation (JCSDA) was established by NASA and NOAA in 2001, with Department of Defense (DoD) agencies becoming partners in 2002. The goal of JCSDA is to accelerate the use of observations from Earth- orbiting satellites in operational environmental analysis and prediction models for the purpose of improving weather, ocean, climate, and air quality forecasts and the accuracy of climate datasets. Advanced instruments of current and planned satellite missions do and will increasingly provide large volumes of data related to the atmospheric, oceanic, and land surface state. During this decade, this will result in a five order of magnitude increase in the volume of data available for use by the operational and research weather, ocean, and climate communities. These data will exhibit accuracies and spatial, spectral, and temporal resolutions never before achieved. JCSDA will help ensure that the maximum benefit from investment in the space-based global observation system is realized. JCSDA will accelerate the use of satellite data from both operational and experimental spacecraft for weather and climate prediction systems. To this end, the advancement of data assimilation science by JCSDA has included the establishment of the JCSDA Community Radiative Transfer Model (CRTM), which has continual upgrades to allow for the effective use of current and many future satellite instruments. This and other activity within JCSDA have been supported by both internal and external (generally university based) research. Another key activity within JCSDA has been to lay the groundwork for and to establish common NWP model and data assimilation infrastructure for accessing new satellite data and optimizing the use of these data in operational models. As a result of this activity, common assimilation infrastructure has been established at NOAA and NASA and this will assist in a coordinated and integrated move to four-dimensional assimilation among the partner agencies. This paper discusses the establishment of JCSDA and its mission, goals, and science priorities. It also discusses recent advances made by JCSDA, and planned future developments. C1 NOAA, Ctr Sci, Joint Ctr Satellite Data Assimilat, Camp Springs, MD 20746 USA. Univ Maryland, ESSIC, College Pk, MD 20742 USA. NOAA, Ctr Sci, NCEP, NWS, Camp Springs, MD 20746 USA. NASA, Goddard Space Flight Ctr, GMAO, Greenbelt, MD 20771 USA. NOAA, Ctr Sci, STAR, NESDIS, Camp Springs, MD 20746 USA. USN, Res Lab, Monterey, CA USA. NOAA, OAR, NOAA Headquarters, Silver Spring, MD 20910 USA. NOAA, Ctr Sci, EMC, NWS, Camp Springs, MD 20746 USA. RP Le Marshall, J (reprint author), NOAA, Ctr Sci, Joint Ctr Satellite Data Assimilat, 5200 Auth Rd, Camp Springs, MD 20746 USA. EM john.lemarshall@noaa.gov RI Weng, Fuzhong/F-5633-2010 OI Weng, Fuzhong/0000-0003-0150-2179 NR 35 TC 7 Z9 7 U1 0 U2 4 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0003-0007 J9 B AM METEOROL SOC JI Bull. Amer. Meteorol. Soc. PD MAR PY 2007 VL 88 IS 3 BP 329 EP + DI 10.1175/BAMS-88-3-329 PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 156AR UT WOS:000245620700010 ER PT J AU Black, PG D'Asaro, EA Drennan, WM French, JR Niiler, PP Sanford, TB Terrill, EJ Walsh, EJ Zhang, JA AF Black, Peter G. D'Asaro, Eric A. Drennan, William M. French, Jeffrey R. Niiler, Pearn P. Sanford, Thomas B. Terrill, Eric J. Walsh, Edward J. Zhang, Jun A. TI Air-sea exchange in hurricanes - Synthesis of observations from the coupled boundary layer air-sea transfer experiment SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article ID SURFACE WIND FIELDS; TROPICAL CYCLONES; OCEAN; INTENSITY; STRESS; VERIFICATION; COEFFICIENTS; PREDICTION; LANDFALL; ROLLS AB The Coupled Boundary Layer Air-Sea Transfer (CBLAST) field program, conducted from 2002 to 2004, has provided a wealth of new air-sea interaction observations in hurricanes. The wind speed range for which turbulent momentum and moisture exchange coefficients have been derived based upon direct flux measurements has been extended by 30% and 60%, respectively, from airborne observations in Hurricanes Fabian and Isabel in 2003. The drag coefficient (C-D) values derived from CBLAST momentum flux measurements show C-D becoming invariant with wind speed near a 23 m s(-1) threshold rather than a hurricane-force threshold near 33 m s-(1.) Values above 23 m s(-1) are lower than previous open-ocean measurements. The Dalton number estimates (C-E) derived from CBLAST moisture flux measurements are shown to be invariant with wind speeds up to 30 m s(-1), which is in approximate agreement with previous measurements at lower winds. These observations imply a C-E/C-D ratio of approximately 0.7, suggesting that additional energy sources are necessary for hurricanes to achieve their maximum potential intensity. One such additional mechanism for augmented moisture flux in the boundary layer might be "roll vortex" or linear coherent features, observed by CBLAST 2002 measurements to have wavelengths of 0.9-1.2 km. Linear features of the same wavelength range were observed in nearly concurrent RADARSAT Synthetic Aperture Radar (SAR) imagery. As a complement to the aircraft measurement program, arrays of drifting buoys and subsurface floats were successfully deployed ahead of Hurricanes Fabian (2003) and Frances (2004) [16 (6) and 38 (14) drifters (floats), respectively, in the two storms]. An unprecedented set of observations was obtained, providing a four-dimensional view of the ocean response to a hurricane for the first time ever. Two types of surface drifters and three types of floats provided observations of surface and sub-surface oceanic currents, temperature, salinity, gas exchange, bubble concentrations, and surface wave spectra to a depth of 200 m on a continuous basis before, during, and after storm passage, as well as surface atmospheric observations of wind speed (via acoustic hydrophone) and direction, rain rate, and pressure. Float observations in Frances (2004) indicated a deepening of the mixed layer from 40 to 120 m in approximately 8 h, with a corresponding decrease in SST in the right-rear quadrant of 3.2 degrees C in 11 h, roughly one-third of an inertial period. Strong inertial currents with a peak amplitude of 1.5 m s(-1) were observed. Vertical structure showed that the critical Richardson number was reached sporadically during the mixed-layer deepening event, suggesting shear-induced mixing as a prominent mechanism during storm passage. Peak significant waves of 11 m were observed from the floats to complement the aircraft-measured directional wave spectra. C1 NOAA, Atlantic Oceanog & Meteorol Lab, Hurricane Res Div, Miami, FL 33149 USA. Univ Washington, Appl Phys Lab, Seattle, WA 98105 USA. Univ Miami, Rosenstiel Sch Marine & Atmospher Sci, Miami, FL 33149 USA. Univ Wyoming, Dept Atmospher Sci, Laramie, WY 82071 USA. Univ Calif San Diego, Scripps Inst Oceanog, La Jolla, CA 92093 USA. NOAA, Earth Syst Res Lab, NASA, Goddard Space Flight Ctr, Boulder, CO USA. RP Black, PG (reprint author), NOAA, Atlantic Oceanog & Meteorol Lab, Hurricane Res Div, Miami, FL 33149 USA. EM Peter.Black@noaa.gov RI Zhang, Jun/F-9580-2012 NR 41 TC 222 Z9 231 U1 3 U2 34 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0003-0007 J9 B AM METEOROL SOC JI Bull. Amer. Meteorol. Soc. PD MAR PY 2007 VL 88 IS 3 BP 357 EP + DI 10.1175/BAMS-88-3-357 PG 20 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 156AR UT WOS:000245620700012 ER PT J AU Hurst, TP AF Hurst, Thomas P. TI Thermal effects on behavior of juvenile walleye pollock (Theragra chalcogramma): implications for energetics and food web models SO CANADIAN JOURNAL OF FISHERIES AND AQUATIC SCIENCES LA English DT Article ID EASTERN BERING SEA; VERTICAL-DISTRIBUTION; PREDATION RISK; MARINE FISH; TEMPERATURE; MECHANISMS; SALMON; ENVIRONMENTS; METABOLISM; RESPONSES AB The behavioral responses of fishes to temperature variation have received little attention despite their direct implications to bioenergetics-based models of production and encounter-based models of food web dynamics. Behavioral characteristics of juvenile walleye pollock (Theragra chalcogramma), a pelagic marine zooplanktivore, were examined between 2 and 9 degrees C in large arenas. Routine swim speed, path sinuosity, and schooling cohesiveness of fish in small groups were described from overhead video observations. In a separate experiment, maximum swimming speeds were measured in a recirculating flume. Routine and maximum swimming speeds had contrasting responses to temperature demonstrating a behavioral rather than physiological regulation of activity level. Routine swim speed was 48% faster at 2 degrees C than at 9 degrees C. This result is inconsistent with the assumption of a constant activity multiplier for metabolism incorporated into most bioenergetics models of fish growth. Increased swim speed, along with the reduced path sinuosity observed at low temperatures, may reflect kinetic aspects of habitat selection. Group cohesion increased at low temperatures, with nearest neighbors averaging 32% closer at 2 degrees C than at 9 degrees C. These results demonstrate that representative models of energy flow through marine food webs depend on an improved understanding of the behavioral as well as physiological responses of fishes to thermal variation. C1 NOAA, Natl Marine Fisheries Serv, Fisheries Behav Ecol Program, Alaska Fisheries Sci Ctr,Hatfield Marine Sci Ctr, Newport, OR 97365 USA. RP Hurst, TP (reprint author), NOAA, Natl Marine Fisheries Serv, Fisheries Behav Ecol Program, Alaska Fisheries Sci Ctr,Hatfield Marine Sci Ctr, 2030 S Marine Sci Dr, Newport, OR 97365 USA. EM thomas.hurst@noaa.gov RI Hurst, Thomas/N-1401-2013 NR 54 TC 14 Z9 15 U1 2 U2 21 PU NATL RESEARCH COUNCIL CANADA-N R C RESEARCH PRESS PI OTTAWA PA BUILDING M 55, OTTAWA, ON K1A 0R6, CANADA SN 0706-652X J9 CAN J FISH AQUAT SCI JI Can. J. Fish. Aquat. Sci. PD MAR PY 2007 VL 64 IS 3 BP 449 EP 457 DI 10.1139/F07-025 PG 9 WC Fisheries; Marine & Freshwater Biology SC Fisheries; Marine & Freshwater Biology GA 163UM UT WOS:000246188700007 ER PT J AU Jensen, KA Ripoll, JF Wray, AA Joseph, D El Hafi, M AF Jensen, Kirk A. Ripoll, Jean-Francois Wray, Alan A. Joseph, David El Hafi, Mouna TI On various modeling approaches to radiative heat transfer in pool fires SO COMBUSTION AND FLAME LA English DT Article DE fire; radiation; discrete ordinates; discrete transfer; Monte Carlo; ray tracing; M-1 model ID 2-DIMENSIONAL AXISYMMETRICAL ENCLOSURES; NET-EXCHANGE FORMULATION; REFLECTIVE SURFACES; UNSTRUCTURED MESHES; COMPARTMENT FIRES; SOOT; PREDICTION; SCHEMES AB Six computational methods for solution of the radiative transfer equation in an absorbing-emitting, nonscattering gray medium were compared for a 2-m JP-8 pool fire. The emission temperature and absorption coefficient fields were taken from a synthetic fire due to the lack of a complete set of experimental data for computing radiation for large and fully turbulent fires. These quantities were generated by a code that has been shown to agree well with the limited quantity of relevant data in the literature. Reference solutions to the governing equation were determined using the Monte Carlo method and a ray-tracing scheme with high angular resolution. Solutions using the discrete transfer method (DTM), the discrete ordinates method (DOM) with both S-4 and LC (11) quadratures, and a moment model using the M-1 closure were compared to the reference solutions in both isotropic and anisotropic regions of the computational domain. Inside the fire, where radiation is isotropic, all methods gave comparable results with good accuracy. Predictions of DTM agreed well with the reference solutions, which is expected for a technique based on ray tracing. DOM LCI11 was shown to be more accurate than the commonly used S4 quadrature scheme, especially in anisotropic regions of the fire domain. On the other hand, DOM S4 gives an accurate source term and, in isotropic regions, correct fluxes. The M-1 results agreed well with other solution techniques and were comparable to DOM S4. This represents the first study where the M, method was applied to a combustion problem occurring in a complex three-dimensional geometry. Future applications of M-1 to fires and similar problems are recommended, considering its similar accuracy and the fact that it has significantly lower computational cost than DOM S4. (c) 2006 The Combustion Institute. Published by Elsevier Inc. All rights reserved. C1 Sandia Natl Labs, Fire Sci & Technol Dept, Albuquerque, NM 87185 USA. Stanford Univ, Ctr Turbulence Res, Stanford, CA 94305 USA. NASA, Ames Res Ctr, Phys Simulat & Modeling Off, Moffett Field, CA 94035 USA. Ecole Mines Albi, Lab Genie Proc Solides Div, F-81013 Albi 09, France. RP Jensen, KA (reprint author), Sandia Natl Labs, Fire Sci & Technol Dept, POB 5800, Albuquerque, NM 87185 USA. EM kajens@sandia.gov; ripoll@lanl.gov NR 52 TC 28 Z9 28 U1 1 U2 8 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0010-2180 J9 COMBUST FLAME JI Combust. Flame PD MAR PY 2007 VL 148 IS 4 BP 263 EP 279 DI 10.1016/j.combustflame.2006.09.008 PG 17 WC Thermodynamics; Energy & Fuels; Engineering, Multidisciplinary; Engineering, Chemical; Engineering, Mechanical SC Thermodynamics; Energy & Fuels; Engineering GA 137JH UT WOS:000244288400007 ER PT J AU Guruswamy, GP AF Guruswamy, G. P. TI Development and applications of a large scale fluids/structures simulation process on clusters SO COMPUTERS & FLUIDS LA English DT Article AB A modular process for efficiently solving large-scale multidisciplinary problems using single-image cluster supercomputers is presented. The process integrates disciplines with diverse physical characteristics while retaining the efficiency of individual disciplines. Computational domain independence of individual disciplines is maintained using a meta programming approach. The process integrates disciplines without affecting the combined performance. The procedure includes an efficient load balancing scheme suitable for parallel computers. Results are demonstrated for large-scale aerospace problems. The super scalability and portability of the approach is demonstrated on several parallel supercomputers. (c) 2006 Elsevier Ltd. All rights reserved. C1 NASA, Ames Res Ctr, NASA Adv Supercomp NAS Div, Moffett Field, CA 94035 USA. RP Guruswamy, GP (reprint author), NASA, Ames Res Ctr, NASA Adv Supercomp NAS Div, MS T27B-1, Moffett Field, CA 94035 USA. EM guru.p.guruswamy@nasa.gov NR 23 TC 5 Z9 5 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0045-7930 J9 COMPUT FLUIDS JI Comput. Fluids PD MAR PY 2007 VL 36 IS 3 BP 530 EP 539 DI 10.1016/j.compfluid.2006.03.005 PG 10 WC Computer Science, Interdisciplinary Applications; Mechanics SC Computer Science; Mechanics GA 129GI UT WOS:000243716200004 ER PT J AU Mattsson, K Svard, M Carpenter, M Nordstrom, J AF Mattsson, Ken Svard, Magnus Carpenter, Mark Nordstrom, Jan TI High-order accurate computations for unsteady aerodynamics SO COMPUTERS & FLUIDS LA English DT Article ID FINITE-DIFFERENCE SCHEMES; BOUNDARY-VALUE-PROBLEMS; CONVERGENCE RATE; SHOCK; APPROXIMATIONS; RESOLUTION; EQUATIONS; MESHES; FLOWS; EULER AB A high-order accurate finite difference scheme is used to perform numerical studies on the benefit of high-order methods. The main advantage of the present technique is the possibility to prove stability for the linearized Euler equations on a multi-block domain, including the boundary conditions. The result is a robust high-order scheme for realistic applications. Convergence studies are presented, verifying design order of accuracy and the superior efficiency of high-order methods for applications dominated by wave propagation. Furthermore, numerical computations of a more complex problem, a vortex-airfoil interaction, show that high-order methods are necessary to capture the significant flow features for transient problems and realistic grid resolutions. This methodology is easy to parallelize due to the multi-block capability. Indeed, we show that the speedup of our numerical method scales almost linearly with the number of processors. (c) 2006 Elsevier Ltd. All rights reserved. C1 Stanford Univ, Ctr Turbulence Res, Stanford, CA 94305 USA. Uppsala Univ, Dept Informat Technol, Uppsala, Sweden. NASA, Langley Res Ctr, Computat Modeling & Simulat Branch, Hampton, VA 23681 USA. Swedish Def Res Agcy, Div Syst Technol, Dept Computat Phys, SE-16490 Stockholm, Sweden. RP Mattsson, K (reprint author), Stanford Univ, Ctr Turbulence Res, Bldg 500, Stanford, CA 94305 USA. EM mattsson@stanford.edu; svard@stanford.edu OI Nordstrom, Jan/0000-0002-7972-6183 NR 40 TC 21 Z9 22 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0045-7930 EI 1879-0747 J9 COMPUT FLUIDS JI Comput. Fluids PD MAR PY 2007 VL 36 IS 3 BP 636 EP 649 DI 10.1016/j.compfluid.2006.02.004 PG 14 WC Computer Science, Interdisciplinary Applications; Mechanics SC Computer Science; Mechanics GA 129GI UT WOS:000243716200012 ER PT J AU Summers, RL Martin, DS Meck, JV Coleman, TG AF Summers, Richard L. Martin, David S. Meck, Janice V. Coleman, Thomas G. TI Computer systems analysis of spaceflight induced changes in left ventricular mass SO COMPUTERS IN BIOLOGY AND MEDICINE LA English DT Article DE computer model; system analysis; venticular mass; spaceflight; microgravity; astronaut ID POSTSPACEFLIGHT ORTHOSTATIC HYPOTENSION; HYPERTENSIVE PATIENTS; TIME COURSE; DURATION SPACEFLIGHT; PRESSURE OVERLOAD; CARDIAC ATROPHY; BED-REST; HYPERTROPHY; REGRESSION; MICROGRAVITY AB Circulatory adaptations resulting in postflight orthostasis have frequently been observed in response to space travel. It has been postulated that a decrement in left ventricular mass (LVM) found after microgravity exposure may be the central component in this cardiovascular deconditioning. However, a physiologic mechanism responsible for these changes in the myocardium has not been determined. In this study, we examined the sequential alterations in echocardiographic measured LVM from preflight to landing day and 3 days into the postflight recovery period. In a previous study in returning astronauts we found a comparative 9.1% reduction in postflight LVM that returned to preflight values by the third day of recovery. This data was further evaluated in a systems analysis approach using a well-established advanced computer model of circulatory functioning. The computer model incorporates the physiologic responses to changes in pressures, flows and hydraulics within the circulatory system as affected by gravitational forces. Myocardial muscle progression to atrophy or hypertrophy in reaction to the circulatory load conditions is also included in the model. The integrative computer analysis suggests that these variations in LVM could be explained by simple fluid shifts known to occur during spaceflight and can reverse within a few days after reentry into earth's gravity. According to model predictions, the reductions in LVM found upon exposure to microgravity are a result of a contraction of the myocardial interstitial fluid space secondary to a loss in the plasma volume. This hypothesis was additionally supported by the published ground-based study in which we followed the alterations in LVM and plasma volume in normal subjects in which hypovolemia was induced by simple dehydration. In the hypovolemic state, plasma volume was reduced in these subjects and was significantly correlated with echocardiographic measurements of LVM. Based on these experimental findings and the performance of the computer systems analysis it appears that reductions in LVM observed after spaceflight may be secondary to fluid exchanges produced by common physiologic mechanisms. Reductions in LVM observed after microgravity exposure have been previously postulated to be a central component of spaceflight-induced cardiovascular deconditioning. However, a recent study has demonstrated a return of astronauts' LVM to preflight values by the third day after landing through uncertain mechanisms. A systems analysis approach using computer simulation techniques allows for a dissection of the complex physiologic control processes and a more detailed examination of the phenomena. From the simulation studies and computer analysis it appears that microgravity induced reductions in LVM may be explained by considering physiologic fluid exchanges rather than cardiac muscle atrophy. (c) 2006 Elsevier Ltd. All rights reserved. C1 Univ Mississippi, Med Ctr, Dept Emergency Med, Jackson, MS 39216 USA. NASA, Lyndon B Johnson Space Ctr, Wyle Labs, Houston, TX 77058 USA. NASA, Human Adaptat & Countermeasures Off, Space & Life Sci Directorate, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. Univ Mississippi, Med Ctr, Dept Physiol & Biophys, Jackson, MS 39216 USA. RP Summers, RL (reprint author), Univ Mississippi, Med Ctr, Dept Emergency Med, Jackson, MS 39216 USA. EM rsummers@pol.net NR 38 TC 14 Z9 17 U1 2 U2 11 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0010-4825 J9 COMPUT BIOL MED JI Comput. Biol. Med. PD MAR PY 2007 VL 37 IS 3 BP 358 EP 363 DI 10.1016/j.compbiomed.2006.04.003 PG 6 WC Biology; Computer Science, Interdisciplinary Applications; Engineering, Biomedical; Mathematical & Computational Biology SC Life Sciences & Biomedicine - Other Topics; Computer Science; Engineering; Mathematical & Computational Biology GA 138IZ UT WOS:000244357600011 PM 16808910 ER PT J AU Fedele, F AF Fedele, Francesco TI Explaining extreme waves by a theory of stochastic wave groups SO COMPUTERS & STRUCTURES LA English DT Article; Proceedings Paper CT 3rd MIT Conference on Computational Fluid and Solid Mechanics CY JUN 14-17, 2005 CL MIT, Cambridge, MA HO MIT DE extreme crest; Zakharov equation; Benjamin-Feir instability; probability of exceedance; freak wave; quasi-determinism ID GAUSSIAN RANDOM-FIELDS; OCEANIC SEA STATES; REGRESSION APPROXIMATIONS; EXPECTED STRUCTURE; GRAVITY-WAVES; FREAK WAVES; DEEP-WATER; SURFACE; DISTRIBUTIONS; AMPLITUDE AB It is well known that in a Gaussian sea an extreme wave event is a particular realization of the space-time evolution of a well defined linear wave group, in agreement with the theory of quasi-determinism of Boccotti [Boccotti P. On mechanics of irregular gravity waves. Atti Ace Naz Lincei, Memorie 1989;19:11-170] and the Slepian model of Lindgren [Kac M, Slepian D. Large excursions of Gaussian processes. Ann Math Statist 1959;30:1215-28; Lindgren G. Some properties of a normal process near a local maximum. Ann Math Statist 1970;4(6):1870-83]. In this paper, the concept of stochastic wave groups is proposed to explain the occurrence of extreme waves in nonlinear random seas, according to the dynamics imposed by the Zakharov equation [Zakharov VE. Statistical theory of gravity and capillary waves on the surface of a finite-depth fluid. J Eur Mech B-Fluids 1999;18(3):327-44]. As a corollary, a new analytical solution for the probability of excecdance of the crest-to-trough height is derived for the prediction of extreme wave events in nonlinearly modulated long-crested narrow-band seas. Furthermore, a generalization of the Tayfun distribution [Tayfun MA. On narrow-band representation of ocean waves. Part 1: Theory. J Geophys Res 1986;91(C6):7743-52] for the wave crest height is also provided. The new analytical distributions explain qualitatively well recent experimental results of Onorato et al. [Onorato M, Osborne AR, Cavaleri L, Brandini C, Stansberg CT. Observation of strongly non-Gaussian statistics for random sea surface gravity waves in wave flume experiments. Phys Rev E 2004;70:067302] and the numerical simulations of Socquet-Juglard et al. [Socquet-Juglard H, Dysthe K, Trulsen K, Krostad HE, Liu J. Probability distributions of surface gravity waves during spectral changes. J Fluid Mech 2005;542:195-216]. 9 (c) 2006 Elsevier Ltd. All rights reserved. C1 Univ Maryland Baltimore Cty, Goddard Earth Sci Technol Ctr, Baltimore, MD 21228 USA. NASA, Goddard Space Flight Ctr, Global Modeling & Assimilat Off, Greenbelt, MD 20771 USA. RP Fedele, F (reprint author), Univ Maryland Baltimore Cty, Goddard Earth Sci Technol Ctr, Baltimore, MD 21228 USA. EM fedele@gmao.gsfc.nasa.gov RI Fedele, Francesco/J-7651-2012 OI Fedele, Francesco/0000-0001-6403-4224 NR 42 TC 3 Z9 3 U1 0 U2 4 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0045-7949 J9 COMPUT STRUCT JI Comput. Struct. PD MAR PY 2007 VL 85 IS 5-6 BP 291 EP 303 DI 10.1016/j.compstruc.2006.10.007 PG 13 WC Computer Science, Interdisciplinary Applications; Engineering, Civil SC Computer Science; Engineering GA 152VK UT WOS:000245389900007 ER PT J AU Parsons, VS AF Parsons, Vickie S. TI Searching for "Unknown Unknowns" SO EMJ-ENGINEERING MANAGEMENT JOURNAL LA English DT Article DE data mining; trending; risk management; unsupervised learning; unknowns; project problems AB Problems are better prevented than solved. The data that is critical for detecting indicators of potential problems usually exist in a plethora of dissimilar databases. Electronic data mining is a particularly promising tool for unsupervised learning of common factors from varied data sources. This paper describes a systematic evaluation of available data mining software packages, based oil documented decision techniques using weighted criteria. This critical first step in identifying unknown unknowns before they become problems is applicable to any set of engineering or programmatic data. C1 NASA, Langley Res Ctr, Greenbelt, MD USA. RP Parsons, VS (reprint author), NASA, Langley Res Ctr, Greenbelt, MD USA. EM v.parsons@charter.net NR 9 TC 3 Z9 3 U1 0 U2 2 PU AMER SOC ENGINEERING MANAGEMENT PI ROLLA PA PO BOX 820, ROLLA, MO 65402 USA SN 1042-9247 J9 EMJ-ENG MANAG J JI EMJ-Eng. Manag. J. PD MAR PY 2007 VL 19 IS 1 BP 43 EP 46 PG 4 WC Engineering, Industrial; Management SC Engineering; Business & Economics GA 338FP UT WOS:000258492000006 ER PT J AU Cleverly, D Ferrario, J Byrne, C Riggs, K Joseph, D Hartford, P AF Cleverly, David Ferrario, Joseph Byrne, Christian Riggs, Karen Joseph, Darrell Hartford, Pamela TI A general indication of the contemporary background levels of PCDDs, PCDFs, and coplanar PCBs in the ambient air over rural and remote areas of the united states SO ENVIRONMENTAL SCIENCE & TECHNOLOGY LA English DT Article ID DIBENZO-P-DIOXINS; POLYCYCLIC AROMATIC-HYDROCARBONS; ATMOSPHERE; CHEMICALS; PAHS AB Long-term measurements of the atmospheric concentrations of PCDDs, PCDFs, and coplanar PCBs were taken in rural and remote areas of the United States by the National Dioxin Air Monitoring Network (NDAMN). A total of 21 quarterly sampling moments occurred from June, 1998 to December, 2002 at 34 locations geographically distributed throughout the United States. Sampling sites were located in rural and remote areas to obtain background air concentrations of dioxin-like compounds. Results were reported as the toxic equivalent (TEQ) of the mix of PCDDs/PCDFs (TEQ(DF)) and the mix of coplanar PCBs (TEQ(PCB)). At the studied rural sites the mean annual TEQ(DF) for each of the NDAMN sampling years was 10.43, 11.39, 10.40, and 10.47 fg m(-3) for 1999, 2000, 2001, and 2002, respectively. There was no statistically significant difference in the rural mean TEQ(DF) air concentrations across the sampling years (at 0.05 level of significance), although the mean concentration in sampling year 2000 increased 10% relative to the other sampling years. The 95th percent confidence interval of TEQ(DF) air concentrations in rural areas of the United States is from 6.4 to 15.4 fg m(-3), indicating there is a 95% probability that the true mean falls within this range. Mean annual atmospheric concentrations (TEQ(DF)) at the remote sites were 1.41, 0.99, 0.7, and 1.07 fg m(-3) in 1999, 2000, 2001, and 2002, respectively. The 95th percent confidence interval of TEQ(DF) air concentrations suggest that the true mean annual atmospheric TEQ(DF) concentration in remote areas of the United States is between 0.1 and 3 fg m(-3). The remote sites have average air TEQ(DF) concentrations that are approximately 10 times lower than those of the rural sites. For the rural sites, there was close agreement in the mean annual air concentrations of coplanar PCBs (TEQ(PCB)) among the years 1999, 2000, 2001, and 2002 (i.e., 0.62, 0.69, 0.59, and 0.7 fg m(-3), respectively). However, as is the case with PCDDs/PCDFs, there was a marked increase (i.e., approximate to 13%) in the annual rural mean air concentration in 2000 as compared to the other sampling years. The confidence intervals across the NDAMN sampling years suggests a 95% probability that mean TEQ(PCB) atmospheric concentrations in rural and remote areas of the United States are within the range of 0.5-0.9 fg m(-3)and 0.1-0.5 fg m(-3), respectively. The congener distributional patterns of PCDDs/PCDFs in air were relatively constant at all locations, and match the profile of urban air. We propose the hypothesis that urban areas are regional sources of PCDDs/PCDFs and are affecting atmospheric levels in rural and remote areas of the United States. C1 US EPA, Natl Ctr Environm Assessment, Off Res & Dev, Washington, DC 20460 USA. Battelle Mem Inst, Columbus, OH 43201 USA. Stennis Space Ctr, US Environm Protect Agcy, Off Pesticide Proggrams, Environm Chem Lab, Mississippi State, MS USA. RP Cleverly, D (reprint author), US EPA, Natl Ctr Environm Assessment, Off Res & Dev, 8623N, Washington, DC 20460 USA. EM cleverly.david@epa.gov NR 21 TC 55 Z9 58 U1 2 U2 12 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0013-936X J9 ENVIRON SCI TECHNOL JI Environ. Sci. Technol. PD MAR 1 PY 2007 VL 41 IS 5 BP 1537 EP 1544 DI 10.1021/es0616736 PG 8 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA 139XZ UT WOS:000244467500015 PM 17396638 ER PT J AU Tzortziou, M Subramaniam, A Herman, JR Gallegos, CL Neale, PJ Harding, LW AF Tzortziou, Maria Subramaniam, Ajit Herman, Jay R. Gallegos, Charles L. Neale, Patrick J. Harding, Lawrence W., Jr. TI Remote sensing reflectance and inherent optical properties in the mid Chesapeake Bay SO ESTUARINE COASTAL AND SHELF SCIENCE LA English DT Article DE bio-optics; satellite retrievals; Case 2; estuaries; coastal waters ID DISSOLVED ORGANIC-MATTER; BULK REFRACTIVE-INDEX; CASE 2 WATERS; CHLOROPHYLL-A; OCEAN COLOR; COASTAL WATERS; BIDIRECTIONAL REFLECTANCE; ABSORPTION-COEFFICIENTS; NATURAL PHYTOPLANKTON; DIFFUSE-REFLECTANCE AB We used an extensive set of bio-optical data to examine the relationships between inherent optical properties and remotely sensed quantities in an optically complex and biologically productive region of the Chesapeake Bay. Field observations showed that the chlorophyll algorithms used by the MODIS (MODerate resolution Imaging Spectroradiometer) ocean color sensor (i.e. Chlor_a, chlor_MODIS, chlor_a_3 products) do not perform accurately in these Case 2 waters. This is because, at high concentrations of chlorophyll, all MODIS algorithms are based on empirical relationships between chlorophyll concentration and blue:green wavelength remote sensing reflectance (R(rs)) ratios that do not account for the typically strong blue-wavelength absorption by non-covarying, dissolved and non-algal particulate components. We found stronger correlation between chlorophyll concentration and red:green R(rs) ratios (i.e. R(rs)(677)/R(rs)(554)). Regionally-specific algorithms that are based on the phytoplankton optical properties in the red wavelength region provide a better basis for satellite monitoring of phytoplankton blooms in these Case 2 waters. Our estimates of f/Q (proportionality factor in the relationship between R(rs) and the ratio of water backscattering, b(b), and absorption, a, coefficients, b(b)/(a + b(b))) were not considerably different from f/Q previously estimated for same measurement geometry but Case 1 waters. Variation in surface bb significantly affected R(rs) magnitude across the visible spectrum and was most strongly correlated (R(2) = 0.88) with observed variability in R(rs) at 670 nm. Surface values of particulate backscattering were strongly correlated with non-algal particulate absorption, a(nap) (R(2) = 0.83). These results, along with the measured backscattering fraction and non-algal particulate absorption spectral slope, indicate that suspended non-algal particles with high inorganic content are the major water constituents regulating b(b) variability in the studied region of the Chesapeake Bay. Remote retrieval of surface a(nap) from R(rs)(670) could be used in conjunction with inversion of UV-blue wavelengths to separate contribution by non-algal particles and colored dissolved organic matter to total light absorption, and monitor non-algal suspended particle concentration and distribution in these Case 2 waters. (c) 2006 Elsevier Ltd. All rights reserved. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Maryland, Earth Syst Sci Interdisciplinary Ctr, College Pk, MD 20742 USA. Columbia Univ, Lamont Doherty Earth Observ, Palisades, NY 10964 USA. Smithsonian Environm Res Ctr, Edgewater, MD 21037 USA. Univ Maryland, Ctr Environm Sci, Horn Point Lab, Cambridge, MD 21613 USA. RP Tzortziou, M (reprint author), NASA, Goddard Space Flight Ctr, Code 613-3,Bldg 33, Greenbelt, MD 20771 USA. EM martz@code613-3.gsfc.nasa.gov RI Neale, Patrick/A-3683-2012; OI Subramaniam, Ajit/0000-0003-1316-5827; Gallegos, Charles/0000-0001-5112-0166; Herman, Jay/0000-0002-9146-1632 NR 83 TC 63 Z9 68 U1 1 U2 10 PU ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 0272-7714 J9 ESTUAR COAST SHELF S JI Estuar. Coast. Shelf Sci. PD MAR PY 2007 VL 72 IS 1-2 BP 16 EP 32 DI 10.1016/j.ecss.2006.09.018 PG 17 WC Marine & Freshwater Biology; Oceanography SC Marine & Freshwater Biology; Oceanography GA 145JZ UT WOS:000244862400002 ER PT J AU Pidgeon, RT Nemchin, AA van Bronswijk, W Geisler, T Meyer, C Compston, W Williams, IS AF Pidgeon, R. T. Nemchin, A. A. van Bronswijk, W. Geisler, T. Meyer, C. Compston, W. Williams, I. S. TI Complex history of a zircon aggregate from lunar breccia 73235 SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Article ID SHOCK-METAMORPHOSED ZIRCON; RAMAN-SPECTROSCOPY; PHASE-TRANSITION; IMPACT; ZRSIO4; COMPRESSIBILITY; GEOCHRONOLOGY AB Results are reported of an investigation of the age and origin of the exceptional zircon aggregate in an anorthositic clast from lunar breccia 73235. Cathodoluminescence and birefringence images show that the aggregate consists of numerous angular fragments of sector zoned primary zircon in a matrix of secondary zircon with an overall texture that resembles a pseudotachylite. SIMS U-Pb analyses of the primary fragments and the matrix yielded two clearly defined ages, an age of 4.315 +/- 10.015 Ga and initial Th/U ratio of 0.21-0.35 for the primary zircon and an age of 4.187 +/- 0.011 Ga and Th/U of 0.04-0.17, for the secondary zircon matrix. A Raman spectroscopic study the secondary matrix zircon was undertaken to investigate its structure. Results showed that the matrix has a zircon structure but there is also evidence for the presence of an amorphous component. Implications of the structural and U-Pb age data are discussed in terms of the origin and evolution of the aggregate and the history of lunar events. It is proposed that an original single, millimetre-sized, sector zoned zircon, formed at 4.31 Ga, was subjected to a severe shock event at 4.18 Ga. This event resulted in the fracturing of the zircon, the displacement and rotation of fragments, the compression of the aggregate to a lensoid shape, and the shock reduction of zircon to sub-micron-sized and amorphous granules in crush zones in the mosaic of fractures. Volatilisation loss of Pb and the addition of U to the secondary zircon is attributed to processes activated by the extreme thermal pulse which accompanied the 4.18 Ga shock event. Shock effects are seen in some of the primary fragments but Raman spectra of the primary and secondary zircon show no evidence for pressure-induced transformation of zircon to a scheelite structure. The zircon U-Pb system has not been affected by the ca. 3.95 Ga thermal pulse that accompanied formation of the host breccia although this event has largely reset the K-Ar systems. (c) 2006 Elsevier Inc. All rights reserved. C1 Curtin Univ Technol, Dept Appl Geol, Bentley, WA 6102, Australia. Curtin Univ Technol, Western Australian Sch Mines, Bentley, WA 6102, Australia. Curtin Univ Technol, Dept Appl Chem, Bentley, WA 6102, Australia. Univ Munster, Inst Mineral, D-48149 Munster, Germany. NASA, Lyndon B Johnson Space Ctr, Astromat Curat KT, Houston, TX 77058 USA. Australian Natl Univ, Res Sch Earth Sci, Canberra, ACT 2601, Australia. RP Pidgeon, RT (reprint author), Curtin Univ Technol, Dept Appl Geol, Bentley, WA 6102, Australia. EM r.pidgeon@curtin.edu.au RI SHRIMP, ANU/F-5312-2011; Williams, Ian/F-4302-2012 OI Williams, Ian/0000-0003-4465-6493 NR 41 TC 36 Z9 38 U1 2 U2 5 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0016-7037 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD MAR 1 PY 2007 VL 71 IS 5 BP 1370 EP 1381 DI 10.1016/j.gca.2006.11.021 PG 12 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 146AE UT WOS:000244906100020 ER PT J AU Ray, RD Cartwright, DE AF Ray, Richard D. Cartwright, David E. TI Times of peak astronomical tides SO GEOPHYSICAL JOURNAL INTERNATIONAL LA English DT Article DE earth tides; ocean tides; tides ID EPHEMERIDES AB The times of maximum tide generating potential, maximum semi-diurnal potential, and maximum diurnal potential for years 1-3000 C.E. are found by direct evaluation from a high-precision numerical ephemeris of the sun and moon. A slight negative trend in the equilibrium peaks of the total tide is caused by the current decrease in the earth's orbital eccentricity, which increases the earth-sun distance at perihelion. Peak diurnal tides are also slightly decreasing owing to the decrease in obliquity. Trends in semi-diurnal tidal peaks are more complicated, tending to decrease until 1247 C.E. and increase thereafter, a result primarily of the influence of the earth's precession on the solar tide. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD USA. RP Ray, RD (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD USA. EM richard.ray@nasa.gov RI Ray, Richard/D-1034-2012 NR 14 TC 4 Z9 4 U1 1 U2 2 PU OXFORD UNIV PRESS PI OXFORD PA GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND SN 0956-540X EI 1365-246X J9 GEOPHYS J INT JI Geophys. J. Int. PD MAR PY 2007 VL 168 IS 3 BP 999 EP 1004 DI 10.1111/j.1365-246X.2006.03293.x PG 6 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 141VK UT WOS:000244606800008 ER PT J AU Friend, AD Arneth, A Kiang, NY Lomas, M Ogee, J Rodenbeckk, C Running, SW Santaren, JD Sitch, S Viovy, N Woodward, FI Zaehle, S AF Friend, Andrew D. Arneth, Almut Kiang, Nancy Y. Lomas, Mark Ogee, Jerome Roedenbeckk, Christian Running, Steven W. Santaren, Jean-Diego Sitch, Stephen Viovy, Nicolas Woodward, F. Ian Zaehle, Sonke TI FLUXNET and modelling the global carbon cycle SO GLOBAL CHANGE BIOLOGY LA English DT Article DE CO2 exchange; eddy covariance; FLUXNET; global carbon cycle; inversion; model ID EDDY COVARIANCE MEASUREMENTS; TERRESTRIAL ECOSYSTEM MODEL; AMAZONIAN RAIN-FOREST; WATER-VAPOR; PHOTOSYNTHETIC CAPACITY; PARAMETER-ESTIMATION; SOIL RESPIRATION; EUROPEAN FORESTS; ATMOSPHERIC DATA; CLIMATE-CHANGE AB Measurements of the net CO2 flux between terrestrial ecosystems and the atmosphere using the eddy covariance technique have the potential to underpin our interpretation of regional CO2 source-sink patterns, CO2 flux responses to forcings, and predictions of the future terrestrial C balance. Information contained in FLUXNET eddy covariance data has multiple uses for the development and application of global carbon models, including evaluation/validation, calibration, process parameterization, and data assimilation. This paper reviews examples of these uses, compares global estimates of the dynamics of the global carbon cycle, and suggests ways of improving the utility of such data for global carbon modelling. Net ecosystem exchange of CO2 (NEE) predicted by different terrestrial biosphere models compares favourably with FLUXNET observations at diurnal and seasonal timescales. However, complete model validation, particularly over the full annual cycle, requires information on the balance between assimilation and decomposition processes, information not readily available for most FLUXNET sites. Site history, when known, can greatly help constrain the model-data comparison. Flux measurements made over four vegetation types were used to calibrate the land-surface scheme of the Goddard Institute for Space Studies global climate model, significantly improving simulated climate and demonstrating the utility of diurnal FLUXNET data for climate modelling. Land-surface temperatures in many regions cool due to higher canopy conductances and latent heat fluxes, and the spatial distribution of CO2 uptake provides a significant additional constraint on the realism of simulated surface fluxes. FLUXNET data are used to calibrate a global production efficiency model (PEM). This model is forced by satellite-measured absorbed radiation and suggests that global net primary production (NPP) increased 6.2% over 1982-1999. Good agreement is found between global trends in NPP estimated by the PEM and a dynamic global vegetation model (DGVM), and between the DGVM and estimates of global NEE derived from a global inversion of atmospheric CO2 measurements. Combining the PEM, DGVM, and inversion results suggests that CO2 fertilization is playing a major role in current increases in NPP, with lesser impacts from increasing N deposition and growing season length. Both the PEM and the inversion identify the Amazon basin as a key region for the current net terrestrial CO2 uptake (i.e. 33% of global NEE), as well as its interannual variability. The inversion's global NEE estimate of -1.2 Pg [C] yr(-1) for 1982-1995 is compatible with the PEM- and DGVM-predicted trends in NPP. There is, thus, a convergence in understanding derived from process-based models, remote-sensing-based observations, and inversion of atmospheric data. Future advances in field measurement techniques, including eddy covariance (particularly concerning the problem of night-time fluxes in dense canopies and of advection or flow distortion over complex terrain), will result in improved constraints on land-atmosphere CO2 fluxes and the rigorous attribution of mechanisms to the current terrestrial net CO2 uptake and its spatial and temporal heterogeneity. Global ecosystem models play a fundamental role in linking information derived from FLUXNET measurements to atmospheric CO2 variability. A number of recommendations concerning FLUXNET data are made, including a request for more comprehensive site data (particularly historical information), more measurements in undisturbed ecosystems, and the systematic provision of error estimates. The greatest value of current FLUXNET data for global carbon cycle modelling is in evaluating process representations, rather than in providing an unbiased estimate of net CO2 exchange. C1 CEA, Ctr Saclay, Lab Sci Climat & Environm, F-91191 Gif Sur Yvette, France. Lund Univ, Dept Phys Geog & Ecosyst Anal, INES, Ctr GeoBiosphere Sci, S-22100 Lund, Sweden. NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Univ Sheffield, Dept Anim & Plant Sci, Sheffield S10 2TN, S Yorkshire, England. INRA, EPHYSE, Funct Ecol & Environm Phys, F-33883 Villenave Dornon, France. Max Planck Inst Biogeochem, D-07701 Jena, Germany. Univ Montana, Sch Forestry, Missoula, MT 59812 USA. Potsdam Inst Klimafolgenforsch eV, D-14412 Potsdam, Germany. RP Friend, AD (reprint author), CEA, Ctr Saclay, Lab Sci Climat & Environm, Orme Merisiers LSCE,Bat 712,Point Courrier 132, F-91191 Gif Sur Yvette, France. EM Andrew.Friend@cea.fr RI Woodward, Ian/B-7762-2008; Ogee, Jerome/C-7185-2013; Arneth, Almut/B-2702-2013; Sitch, Stephen/F-8034-2015; Zaehle, Sonke/C-9528-2017 OI Sitch, Stephen/0000-0003-1821-8561; Zaehle, Sonke/0000-0001-5602-7956 NR 78 TC 119 Z9 122 U1 0 U2 0 PU WILEY-BLACKWELL PI HOBOKEN PA 111 RIVER ST, HOBOKEN 07030-5774, NJ USA SN 1354-1013 EI 1365-2486 J9 GLOBAL CHANGE BIOL JI Glob. Change Biol. PD MAR PY 2007 VL 13 IS 3 BP 610 EP 633 DI 10.1111/j.1365-2486.2006.01223.x PG 24 WC Biodiversity Conservation; Ecology; Environmental Sciences SC Biodiversity & Conservation; Environmental Sciences & Ecology GA 148CT UT WOS:000245052800006 ER PT J AU Groussin, O A'Hearn, MF Li, JY Thomas, PC Sunshine, JM Lisse, CM Meech, KJ Farnham, TL Feaga, LM Delamere, WA AF Groussin, O. A'Hearn, M. F. Li, J. -Y. Thomas, P. C. Sunshine, J. M. Lisse, C. M. Meech, K. J. Farnham, T. L. Feaga, L. M. Delamere, W. A. TI Surface temperature of the nucleus of Comet 9P/Tempel 1 SO ICARUS LA English DT Article DE Comet Tempel-1; comets, nucleus; comets, origin ID THERMAL PHYSICS; DEEP IMPACT; ASTEROIDS; ALBEDO; CHIRON; SIZE AB The Deep Impact (DI) spacecraft encountered Comet 9P/Tempel 1 on July 4th, 2005 and observed it with several instruments. In particular, we obtained infrared spectra of the nucleus with the HRI-IR spectrometer in the wavelength range of 1.0-4.9 mu m. The data were taken before impact, with a maximum resolution of similar to 120 m per pixel at the time of observation. From these spectra, we derived the first directly observed temperature map of a comet nucleus. The surface temperature varied from 272 +/- 7 to 336 +/- 7 K on the sunlit hemisphere, matching the surface topography and incidence angle. The derived thermal inertia is low, most probably < 50 W K-1 m(-2) s(1/2). Combined with other arguments, it is consistent with the idea that most of rapidly varying thermal physical processes, in particular the sublimation of volatiles around perihelion, should occur close to the surface. Thermal inertia is sufficient to explain the temperature map of the nucleus of Comet Tempel 1 to first order, but other physical processes like roughness and self-radiation are required to explain the details of the temperature map. Finally, we evaluated that the Standard Thermal Model is a good approximation to derive the effective radius of a cometary nucleus with an uncertainty lower than similar to 10% if combined with a thermal infrared light curve. (c) 2006 Elsevier Inc. All rights reserved. C1 Univ Maryland, Dept Astron, College Pk, MD 20742 USA. Cornell Univ, Dept Astron, Ithaca, NY 14853 USA. Johns Hopkins Univ, Appl Phys Lab, Laurel, MD 20723 USA. Univ Hawaii, NASA, Astrobiol Inst, Honolulu, HI 96822 USA. Delamere Support Serv, Boulder, CO USA. RP Groussin, O (reprint author), Univ Maryland, Dept Astron, College Pk, MD 20742 USA. EM groussin@astro.umd.edu RI Lisse, Carey/B-7772-2016 OI Lisse, Carey/0000-0002-9548-1526 NR 26 TC 77 Z9 77 U1 0 U2 5 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD MAR PY 2007 VL 187 IS 1 BP 16 EP 25 DI 10.1016/j.icarus.2006.08.030 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 143CO UT WOS:000244697800003 ER PT J AU Li, JY A'Hearn, MF Belton, MJS Crockett, CJ Farnham, TL Lisse, CM McFadden, LA Meech, KJ Sunshine, JM Thomas, PC Veverka, J AF Li, Jian-Yang A'Hearn, Michael F. Belton, Michael J. S. Crockett, Christopher J. Farnham, Tony L. Lisse, Carey M. McFadden, Lucy A. Meech, Karen J. Sunshine, Jessica M. Thomas, Peter C. Veverka, Joe TI Deep impact photometry of Comet 9P/Tempel 1 SO ICARUS LA English DT Article DE Comet 9P/Fempel 1; photometry ID GALILEO PHOTOMETRY; VEGA SPACECRAFT; NUCLEUS; SURFACE; HALLEY; EROS; COMET-9P/TEMPEL-1; SCATTERING; GIOTTO; CAMERA AB The photometric properties of the nucleus of Comet 9P/Tempel 1 are studied from the disk-resolved color images obtained by Deep Impact (DI). Comet Tempel I has typical photometric properties for comets and dark asteroids. The disk-integrated spectrum of the nucleus of Tempel I between 309 and 950 nm is linear without any features at the spectral resolution of the filtered images. At V-band, the red slope of the nucleus is 12.5 +/- 1% per 100 nm at 63 degrees phase angle, translating to B-V = 0.84 +/- 0.01, V-R = 0.50 +/- 0.01, and R-I = 0.49 +/- 0.02. No phase reddening is confirmed. The phase function of the nucleus of Tempel I is constructed from DI images and earlier ground-based observations found from the literature. The phase coefficient is determined to be beta = 0.046 +/- 0.007 mag/deg between 4 degrees and 117 degrees phase angle. Hapke's theoretical scattering model was used to model the photometric properties of this comet. Assuming a single Henyey-Green stein function for the single-particle phase function, the asymmetry factor of Tempel I was fitted to be g = -0.49 +/- 0.02, and the corresponding single-scattering albedo (SSA) was modeled to be 0.039 +/- 0.005 at 550 nm wavelength. The SSA spectrum shows a similar linear slope to that of the disk-integrated spectrum. The roughness parameter is found to be 16 degrees +/- 8 degrees, and independent of wavelength. The Minnaert k parameter is modeled to be 0.680 +/- 0.014. The photometric variations on Tempel I are relatively small compared to other comets and asteroids, with a similar to 20% full width at half maximum of albedo variation histogram, and similar to 3% for color. Roughness variations are evident in one small area, with a roughness parameter about twice the average and appearing to correlate with the complex morphological texture seen in high-resolution images. (c) 2006 Elsevier Inc. All rights reserved. C1 Univ Maryland, Dept Astron, College Pk, MD 20742 USA. Belton Space Explorat Initiat, LLC, Tucson, AZ 85716 USA. Johns Hopkins Univ, Appl Phys Lab, Laurel, MD 20723 USA. Univ Hawaii, Inst Astron, Honolulu, HI 96822 USA. Univ Hawaii, NASA, Astrobiol Inst, Honolulu, HI 96822 USA. Cornell Univ, Ctr Radiophys & Space Res, Ithaca, NY 14853 USA. RP Li, JY (reprint author), Univ Maryland, Dept Astron, College Pk, MD 20742 USA. EM jyli@astro.umd.edu RI McFadden, Lucy-Ann/I-4902-2013; Lisse, Carey/B-7772-2016 OI McFadden, Lucy-Ann/0000-0002-0537-9975; Lisse, Carey/0000-0002-9548-1526 NR 59 TC 48 Z9 48 U1 0 U2 3 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD MAR PY 2007 VL 187 IS 1 BP 41 EP 55 DI 10.1016/j.icarus.2006.09.018 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 143CO UT WOS:000244697800005 ER PT J AU Lisse, CM Kraemer, KE Nuth, JA Li, A Joswiak, D AF Lisse, C. M. Kraemer, K. E. Nuth, J. A., III Li, A. Joswiak, D. TI Comparison of the composition of the Tempel 1 ejecta to the dust in Comet C/Hale-Bopp 1995 01 and YSOHD 100546 SO ICARUS LA English DT Article DE infrared observations; spectroscopy; Comets; origin; comets; composition; solar nebula ID HERBIG AE/BE STARS; O1 HALE-BOPP; PROTOPLANETARY ACCRETION DISKS; POLYCYCLIC AROMATIC MOLECULE; SPITZER-SPACE-TELESCOPE; SOLAR NEBULA; C/1995 O1; DEEP IMPACT; CRYSTALLINE SILICATES; INTERSTELLAR-MEDIUM AB Spitzer Infrared Spectrograph observations of the Deep Impact experiment in July 2005 have created a new paradigm for understanding the infrared spectroscopy of primitive solar nebular (PSN) material-the ejecta spectrum is the most detailed ever observed in cometary material. Here we take the composition model for the material excavated from Comet 9P/Tempel 1's interior and successfully apply it to Infrared Space Observatory spectra of material emitted from Comet C/1995 O1 (Hale-Bopp) and the circumstellar material found around the young stellar object HD 100546. Comparison of our results with analyses of the cometary material returned by the Stardust spacecraft from Comet 81P/Wild 2, the in situ Halley flyby measurements, and the Deep Impact data return provides a fundamental cross-check for the spectral decomposition models presented here. We find similar emission signatures due to silicates, carbonates, phyllosilicates, water ice, amorphous carbon, and sulfides in the two ISO-observed systems but there are significant differences as well. Compared to Tempel 1, no Fe-rich olivines and few crystalline pyroxenes are found in Hale-Bopp and HD 100546. The YSO also lacks amorphous olivine, while being super-rich in amorphous pyroxene. All three systems show substantial emission due to polycyclic aromatic hydrocarbons. The silicate and PAH material in Hale-Bopp is clearly less processed than in Tempel 1, indicating an earlier age of formation for Hale-Bopp. The observed material around HD 100546 is located similar to 13 AU from the central source, and demonstrates an unusual composition due to either a very different, non-solar starting mix of silicates or due to disk material processing during formation of the interior disk cavity and planet(s) in the system. (c) 2006 Elsevier Inc. All rights reserved. C1 Johns Hopkins Univ, Appl Phys Lab, Planetary Explorat Grp, Laurel, MD 20723 USA. AFRL, VSBYB, Hanscom AFB, MA 01731 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Missouri, Dept Phys & Astron, Columbia, MO 65211 USA. Univ Washington, Dept Astron, Seattle, WA 98195 USA. RP Lisse, CM (reprint author), Johns Hopkins Univ, Appl Phys Lab, Planetary Explorat Grp, 11100 Johns Hopkins Rd, Laurel, MD 20723 USA. EM carey.lisse@jhuapl.edu RI Nuth, Joseph/E-7085-2012; Lisse, Carey/B-7772-2016; OI Lisse, Carey/0000-0002-9548-1526; Kraemer, Kathleen/0000-0002-2626-7155 NR 87 TC 62 Z9 62 U1 0 U2 6 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD MAR PY 2007 VL 187 IS 1 BP 69 EP 86 DI 10.1016/j.icarus.2006.11.019 PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 143CO UT WOS:000244697800007 ER PT J AU Feldman, PD McCandliss, SR Route, M Weaver, HA A'Hearn, MF Belton, MJS Meech, KJ AF Feldman, Paul D. McCandliss, Stephan R. Route, Matthew Weaver, Harold A. A'Hearn, Michael F. Belton, Michael J. S. Meech, Karen J. TI Hubble Space Telescope observations of Comet 9P/Tempel 1 during the Deep Impact Encounter SO ICARUS LA English DT Article DE comets; Comet Tempel-1 ID COMET-9P/TEMPEL-1; NUCLEUS AB We report on the Hubble Space Telescope program to observe periodic Comet 9P/Tempel 1 in conjunction with NASA's Deep Impact Mission. Our objectives were to study the generation and evolution of the coma resulting from the impact and to obtain wide-band images of the visual outburst generated by the impact. Two observing campaigns utilizing a total of 17 HST orbits were carried out: the first occurred on 2005 June 1314 and fortuitously recorded the appearance of a new, short-lived fan in the sunward direction on June 14. The principal campaign began two days before impact and was followed by contiguous orbits through impact plus several hours and then snapshots one, seven, and twelve days later. All of the observations were made using the Advanced Camera for Surveys (ACS). For imaging, the ACS High Resolution Channel (HRC) provides a spatial resolution of 36 km (16 km pixel(-1)) at the comet at the time of impact. Baseline images of the comet, made prior to impact, photometrically resolved the comet's nucleus. The derived diameter, 6.1 km, is in excellent agreement with the 6.0 +/- 0.2 km diameter derived from the spacecraft imagers. Following the impact, the HRC images illustrate the temporal and spatial evolution of the ejecta cloud and allow for a determination of its expansion velocity distribution. One day after impact the ejecta cloud had passed out of the field-of-view of the HRC. (c) 2006 Elsevier Inc. All rights reserved. C1 Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. Johns Hopkins Univ, Appl Phys Lab, Dept Space, Laurel, MD 20723 USA. Univ Maryland, Dept Astron, College Pk, MD 20742 USA. Belton Space Explorat Initiat, Tucson, AZ 85716 USA. Univ Hawaii, Astron Inst, Honolulu, HI 96822 USA. NASA, Astrobiol Inst, Honolulu, HI 96822 USA. RP Feldman, PD (reprint author), Johns Hopkins Univ, Dept Phys & Astron, Charles & 34th St, Baltimore, MD 21218 USA. EM pdf@pha.jhu.edu RI Weaver, Harold/D-9188-2016 NR 16 TC 14 Z9 14 U1 0 U2 0 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD MAR PY 2007 VL 187 IS 1 BP 113 EP 122 DI 10.1016/j.icarus.2006.07.027 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 143CO UT WOS:000244697800011 ER PT J AU Mason, KO Chester, M Cucchiara, A Gronwall, C Grupe, D Hunsberger, S Jones, GH Koch, S Nousek, J O'Brien, PT Racusin, J Roming, P Smith, P Wells, A Willingale, R Branduardi-Raymont, G Gehrels, N AF Mason, K. O. Chester, M. Cucchiara, A. Gronwall, C. Grupe, D. Hunsberger, S. Jones, G. H. Koch, S. Nousek, J. O'Brien, P. T. Racusin, J. Roming, P. Smith, P. Wells, A. Willingale, R. Branduardi-Raymont, G. Gehrels, N. TI Swift ultraviolet photometry of the Deep Impact encounter with Comet 9P/Tempel 1 SO ICARUS LA English DT Article DE comets; Comet Tempel-1; comets; composition; comets; coma; comets; dust ID X-RAY TELESCOPE; COMET-9P/TEMPEL-1; MISSION AB We report time-resolved imaging UV photometry of Comet 9P/Tempel 1 during the interval 2005 June 29-2005 July 2 1, including intensive coverage of the collision with the Deep Impact probe and its immediate aftermath. The nuclear flux of the comet begins to rise within minutes of the collision, and peaks about 3 h after impact. There is no evidence for a prompt flash at the time of impact. The comet exhibits a significant rebrightening about 40 It after the initial outburst, consistent with the rotation period of the comet, with evidence for further periodic re-brightenings on subsequent rotations. Modelling of the brightness profile of the coma as a function of time suggests two distinct velocity systems in the ejecta, at de-projected expansion speeds of 190 and 550 m/s, which we suggest are due to dust and gas, respectively. There is a distinct asymmetry in the slower-moving (dust) component as a function of position angle on the sky. This is confirmed by direct imaging analysis, which reveals an expanding plume of material concentrated in the impact hemisphere. The projected expansion velocity of the leading edge of this plume, measured directly from the imaging data, is 190 m/s, consistent with the velocity of the dust component determined from the photometric analysis. From our data we determine that a total of (1.4 +/- 0.2) X 10(32) water molecules were ejected in the impact, together with a total scattering area of dust at 300 nm of 190 +/- 20 km(2). (c) 2006 Elsevier Inc. All rights reserved. C1 UCL, Mullard Space Sci Lab, Dept Space & Climate Phys, Dorking RH5 6NT, Surrey, England. Particle Phys & Astron Res Council, Swindon SN2 1SZ, Wilts, England. Penn State Univ, Dept Astron & Astrophys, Davey Lab 525, University Pk, PA 16802 USA. Max Planck Inst Solar Syst Res, D-37191 Katlenburg Lindau, Germany. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Leicester, Dept Phys & Astron, Leicester LE1 7RH, Leics, England. RP Mason, KO (reprint author), UCL, Mullard Space Sci Lab, Dept Space & Climate Phys, Holmbury St Mary, Dorking RH5 6NT, Surrey, England. EM kom@mssl.ucl.ac.uk RI Racusin, Judith/D-2935-2012; Gehrels, Neil/D-2971-2012; Jones, Geraint/C-1682-2008; OI Jones, Geraint/0000-0002-5859-1136 NR 16 TC 3 Z9 3 U1 0 U2 2 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD MAR PY 2007 VL 187 IS 1 BP 123 EP 131 DI 10.1016/j.icarus.2006.09.021 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 143CO UT WOS:000244697800012 ER PT J AU Hodapp, KW Aldering, G Meech, KJ Cochran, AL Antilogus, P Pecontal, E Chickering, W Blanc, N Copin, Y Lynch, DK Rudy, RJ Mazuk, S Venturini, CC Puetter, RC Perry, RB AF Hodapp, Klaus W. Aldering, Greg Meech, Karen J. Cochran, Anita L. Antilogus, Pierre Pecontal, Emmanuel Chickering, William Blanc, Nathalie Copin, Yannick Lynch, David K. Rudy, Richard J. Mazuk, S. Venturini, Catherine C. Puetter, Richard C. Perry, Raleigh B. TI Visible and near-infrared spectrophotometry of the Deep Impact ejecta of Comet 9P/Tempel 1 SO ICARUS LA English DT Article DE comets; Comet Tempel 1; photometry; spectroscopy ID TELESCOPE; SUPERNOVA; DUST AB We have obtained optical spectrophotometry of the evolution of Comet 9P/Tempel 1 after the impact of the Deep Impact probe, using the Supernova Integral Field Spectrograph (SNIFS) at the UH 2.2-m telescope, as well as simultaneous optical and infrared spectra using the Lick Visible-to-Near-Infrared Imaging Spectrograph (VNIRIS). The spatial distribution and temporal evolution of the "violet band" CN (0-0) emission and of the 630 nm [OI] emission was studied. We found that CN emission centered on the nucleus increased in the 2 h after impact, but that this CN emission was delayed compared to the light curve of dust-scattered sunlight. The CN emission also expanded faster than the cloud of scattering dust. The emission of [OI] at 630 run rose similarly to the scattered light, but then remained nearly constant for several hours after impact. On the day following the impact, both CN and [OI] emission concentrated on the comet nucleus had returned nearly to pre-impact levels. We have also searched for differences in the scattering properties of the dust ejected by the impact compared to the dust released under normal conditions. Compared to the pre-impact state of the comet, we find evidence that the color of the comet was slightly bluer during the post-impact rise in brightness. Long after the impact, in the following nights, the comet colors returned to their pre-impact values. This can be explained by postulating a change to a smaller particle size distribution in the ejecta cloud, in agreement with the findings from mid-infrared observations, or by postulating a large fraction of clean ice particles, or by a combination of these two. (c) 2006 Elsevier Inc. All rights reserved. C1 Univ Hawaii, Astron Inst, Hilo, HI 96720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Div Phys, Berkeley, CA 94720 USA. Univ Hawaii, Inst Astron, Honolulu, HI 96822 USA. NASA, Astrobiol Inst, Hilo, HI 96720 USA. Univ Texas, McDonald Observ, Austin, TX 78712 USA. Aerosp Corp, Los Angeles, CA 90009 USA. Univ Calif San Diego, La Jolla, CA 92093 USA. Univ Calif San Diego, San Diego, CA 92093 USA. NASA, Langley Res Ctr, Sci Support Off, Hampton, VA 23681 USA. Univ Paris 06, Lab Phys Nucl & Hautes Energies, IN2P3, CNRS, F-75252 Paris 05, France. Univ Paris 07, Lab Phys Nucl & Hautes Energies, IN2P3, CNRS, F-75252 Paris 05, France. Ctr Rech Astron Lyon, F-69561 St Genis Laval, France. Univ Lyon 1, Inst Phys Nucl Lyon, CNRS,UMR5822, IN2P3, F-69622 Villeurbanne, France. RP Hodapp, KW (reprint author), Univ Hawaii, Astron Inst, 640 N Aohoku Pl, Hilo, HI 96720 USA. EM hodapp@ifa.hawaii.edu RI Copin, Yannick/B-4928-2015 OI Copin, Yannick/0000-0002-5317-7518 NR 16 TC 4 Z9 4 U1 0 U2 0 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 EI 1090-2643 J9 ICARUS JI Icarus PD MAR PY 2007 VL 187 IS 1 BP 185 EP 198 DI 10.1016/j.icarus.2006.09.015 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 143CO UT WOS:000244697800018 ER PT J AU Fernandez, YR Lisse, CM Kelley, MS Dello Russo, N Tokunaga, AT Woodward, CE Wooden, DH AF Fernandez, Y. R. Lisse, C. M. Kelley, M. S. Dello Russo, N. Tokunaga, A. T. Woodward, C. E. Wooden, D. H. TI Near-infrared light curve of Comet 9P/Tempel 1 during Deep Impact SO ICARUS LA English DT Article DE Comet Tempel-1; infrared observations ID EARTH-BASED CAMPAIGN; ABSOLUTE CALIBRATION; GRAINS; COMET-9P/TEMPEL-1; SPECTROGRAPH; PHOTOMETRY; NUCLEUS; DUST; SPEX AB On UT 2005 July 4 we observed Comet 9P/Tempel 1 during its encounter with the Deep Impact flyby spacecraft and impactor. Using the SpeX near-infrared spectrograph mounted on NASA's Infrared Telescope Facility, we obtained 0.8-to-2.5 mu m flux-calibrated spectral light curves of the comet for 12 min before and 14 min after impact. Our cadence was just 1.1 s. The light curve shows constant flux before the impact and an overall brightening trend after the impact, but not at a constant rate. Within a 0.8-arcsec-radius circular aperture, the comet rapidly-brightened by 0.63 mag at 1.2 mu m in the first minute. Thereafter, brightening was more modest, averaging about 0.091 mag/min at 1.2 Pm, although apparently not quite constant. In addition we see a bluing in the spectrum over the post-impact period of about 0.07 mag in J-H and 0.35 mag in J-K. The majority of this bluing happened in the first minute, and the dust only marginally blued after that, in stark contrast to the continued brightening. The photometric behavior in the light curve is due to a combination of crater formation effects, expansion of the ejecta cloud, and evolution of liberated dust grains. The bluing is likely due to an icy component on those grains, and the icy grains would have had to have a devolatilization timescale longer than 14 min (unless they were shielded by the optical depth of the cloud). The bluing could also have been caused by the decrease in the "typical" size of the dust grains after impact. Ejecta dominated by submicron grains, as inferred from other observations, would have stronger scattering at shorter wavelengths than the much larger grains observed before impact. (c) 2006 Elsevier Inc. All rights reserved. C1 Univ Cent Florida, Dept Phys, Orlando, FL 32816 USA. Johns Hopkins Univ, Appl Phys Lab, Laurel, MD 20723 USA. Univ Minnesota, Dept Astron, Minneapolis, MN 55455 USA. Univ Hawaii, Inst Astron, Honolulu, HI 96822 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Fernandez, YR (reprint author), Univ Cent Florida, Dept Phys, 4000 Cent Florida Blvd, Orlando, FL 32816 USA. EM yan@physics.ucf.edu RI Dello Russo, Neil/G-2727-2015; Lisse, Carey/B-7772-2016; OI Dello Russo, Neil/0000-0002-8379-7304; Lisse, Carey/0000-0002-9548-1526; Kelley, Michael/0000-0002-6702-7676; Fernandez, Yanga/0000-0003-1156-9721 NR 26 TC 12 Z9 12 U1 0 U2 2 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD MAR PY 2007 VL 187 IS 1 BP 220 EP 227 DI 10.1016/j.icarus.2006.09.019 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 143CO UT WOS:000244697800021 ER PT J AU DiSanti, MA Villanueva, GL Bonev, BP Magee-Sauer, K Lyke, JE Mumma, MJ AF DiSanti, Michael A. Villanueva, Geronimo L. Bonev, Boncho P. Magee-Sauer, Karen Lyke, James E. Mumma, Michael J. TI Temporal evolution of parent volatiles and dust in Comet 9P/Tempel 1 resulting from the Deep Impact experiment SO ICARUS LA English DT Article DE comets; spectroscopy; infrared observations ID O1 HALE-BOPP; WATER PRODUCTION; TELESCOPE; NIRSPEC; RELEASE; GRAINS; BAND; LEE; CO AB The Deep Impact encounter with the Jupiter family Comet 9P/Tempel 1 on UT 2005 July 4 was observed at high spectral resolving power (lambda/delta lambda similar to 25,000) using the cross-dispersed near-infrared echelle spectrometer (NIRSPEC) at Keck-2. We report the temporal evolution of parent volatiles and dust (simultaneously measured) resulting from the event. Column abundances are presented for H2O and C2H6 beginning 30 min prior to impact (T - 30) and ending 50 min following impact (T + 50), and for H2O and HCN from T + 50 until T + 96, in time steps of approximately 6 min post-impact. The ejecta composition was revealed by an abrupt increase in H2O and C2H6 near,T + 25. This showed C2H6/H2O to be higher than its pre-impact value by a factor 2.4 +/- 0.5, while HCN/H2O was unchanged within the uncertainty of the measurements. The mixing ratios for C21-16 and HCN in the ejecta agree with those found in the majority of Oort cloud comets, perhaps indicating a common region of formation. The expanding dust plume was tracked by continuum measurements, both through the 3.5-mu m spectral continuum and through 2-mu m images acquired with the SCAM slit-viewing camera, and each showed a monotonic increase in continuum intensity following impact. A Monte Carlo model that included dust opacity was applied to the dust coma, and its parameters were constrained by observations; the simulated continuum intensities reproduced both spectral and SCAM data. The relatively sudden appearance of the volatile ejecta signature is attributed to heating of icy grains (perhaps to a threshold temperature) that are decreasingly shadowed by intervening (sunward) dust particles in an optically thick ejecta plume, perhaps coupled with an accelerated decrease in dust optical depth near T + 25. (c) 2006 Elsevier Inc. All rights reserved. C1 NASA, Goddard Space Flight Ctr, Solar Syst Explorat Div, Greenbelt, MD 20771 USA. Catholic Univ Amer, Dept Phys, Washington, DC 20064 USA. Rowan Univ, Dept Phys & Astron, Glassboro, NJ 08028 USA. WM Keck Observ, Kamuela, HI 96743 USA. NASA, Goddard Space Flight Ctr, Solar Syst Explorat Div, Greenbelt, MD 20771 USA. RP DiSanti, MA (reprint author), NASA, Goddard Space Flight Ctr, Solar Syst Explorat Div, Code 693, Greenbelt, MD 20771 USA. EM disanti@ssedmail.gsfc.nasa.gov RI mumma, michael/I-2764-2013; Magee-Sauer, Karen/K-6061-2015 OI Magee-Sauer, Karen/0000-0002-4979-9875 NR 27 TC 22 Z9 23 U1 1 U2 2 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD MAR PY 2007 VL 187 IS 1 BP 240 EP 252 DI 10.1016/j.icarus.2006.10.007 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 143CO UT WOS:000244697800023 ER PT J AU Bauer, JM Weissman, PR Choi, YJ Troy, M Young, JW Lisse, CM Dekany, R Hanner, MS Buratti, BJ AF Bauer, James M. Weissman, Paul R. Choi, Young-Jun Troy, Mitchell Young, James W. Lisse, Carey M. Dekany, Richard Hanner, Martha S. Buratti, Bonnie J. TI Palomar and Table Mountain observations of 9P/Tempel 1 during the Deep Impact encounter: First results SO ICARUS LA English DT Article DE Comet Tempel-1; adaptive optics; comets, dust ID EARTH-BASED CAMPAIGN; INFRARED PHOTOMETRY; COMET 9P/TEMPEL-1; STEPHAN-OTERMA; STANDARD STARS; KUIPER-BELT; NUCLEUS; BOWELL; SYSTEM; COMET-9P/TEMPEL-1 AB We present the first results of the Palomar Adaptive Optics observations taken during the Deep Impact encounter with 9P/Tempel 1 in July 2005. We have combined the Palomar near-IR imaging data with our visual wavelength images obtained simultaneously at JPL's Table Mountain Observatory to cover the total wavelength range from 0.4 to 2.3 mu m in the B, V, R, I, J, H, and K filter bands, spanning the dates from 2005 July 03-07. We also include in our overall analysis images taken on the pre-encounter dates of June I and June 15, 2005. The broad wavelength range of our observations, along with high temporal resolution, near-IR sensitivity, and spatial resolution of our imaging, have enabled us to place constraints on the temperature of the impact flash and incandescent plume of > 700 K, and to provide mean dust velocities of order 197 +/- 16 m/s approximately 1.25 h after impact derived from our 1.64 mu m observations. Our ejected dust mass estimates, as derived from our near-IR observations, are an order of magnitude less than those previously reported for visual wavelength observations. (c) 2006 Elsevier Inc. All rights reserved. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Johns Hopkins Univ, Appl Phys Lab, SD SRE, Laurel, MD 20723 USA. CALTECH, Dept Astron, Pasadena, CA 91125 USA. Univ Massachusetts, Dept Astron, Lederle Grad Res Ctr, Amherst, MA 01003 USA. RP Bauer, JM (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,Mailstop 183-501, Pasadena, CA 91109 USA. EM bauer@scn.jpl.nasa.gov RI Lisse, Carey/B-7772-2016 OI Lisse, Carey/0000-0002-9548-1526 NR 39 TC 5 Z9 5 U1 0 U2 0 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD MAR PY 2007 VL 187 IS 1 BP 296 EP 305 DI 10.1016/j.icarus.2006.10.035 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 143CO UT WOS:000244697800028 ER PT J AU Gunapala, SD Bandara, SV Hill, CJ Ting, DZ Liu, JK Rafol, SB Blazejewski, ER Mumolo, JM Keo, SA Krishna, S Chang, YC Shott, CA AF Gunapala, Sarath D. Bandara, Sumith V. Hill, Cory J. Ting, David Z. Liu, John K. Rafol, Sir B. Blazejewski, Edward R. Mumolo, Jason M. Keo, Sam A. Krishna, Sanjay Chang, Y. -C. Shott, Craig A. TI 640 x 512 pixels long-wavelength infrared (LWIR) quantum-dot infrared photodetector (QDIP) imaging focal plane array SO IEEE JOURNAL OF QUANTUM ELECTRONICS LA English DT Article DE focal plane array; infrared detector; quantum dots (QDs) ID HIGH-TEMPERATURE OPERATION; A-WELL DETECTOR; RESPONSIVITY; DETECTIVITY AB Epitaxially grown self-assembled. InAs-InGaAs-GaAs quantum dots (QDs) are exploited for the development of large-format long-wavelength infrared focal plane arrays (FPAs). The dot-in-a-well (DWELL) structures were experimentally shown to absorb both 45 degrees and normal incident light, therefore, a reflection grating structure was used to enhance the quantum efficiency. The devices exhibit peak responsivity out to 8.1 mu m, with peak detectivity reaching similar to 1 X 10(10) Jones at 77 K. The devices were fabricated into the first long-wavelength 640 x 512 pixel QD infrared photodetector imaging FPA, which has produced excellent infrared imagery with noise equivalent temperature difference of 40 mK at 60-K operating temperature. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Illinois, Dept Phys, Urbana, IL 61801 USA. Infravis Syst, Altadena, CA 91001 USA. Univ New Mexico, Albuquerque, NM 87106 USA. FLIR Syst Inc, Indigo Operat, Goleta, CA 93117 USA. RP Gunapala, SD (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM Sarath.d.Gunapala@jpl.nasa.gov RI Krishna, Sanjay /C-5766-2009; Chang, Yia-Chung/F-4239-2011 NR 21 TC 64 Z9 64 U1 3 U2 9 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 0018-9197 J9 IEEE J QUANTUM ELECT JI IEEE J. Quantum Electron. PD MAR-APR PY 2007 VL 43 IS 3-4 BP 230 EP 237 DI 10.1109/JQE.2006.889645 PG 8 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA 156VJ UT WOS:000245677700003 ER PT J AU Radisic, V Mei, XB Deal, WR Yoshida, W Liu, PH Uyeda, J Barsky, M Samoska, L Fung, A Gaier, T Lai, R AF Radisic, V. Mei, X. B. Deal, W. R. Yoshida, W. Liu, P. H. Uyeda, J. Barsky, M. Samoska, L. Fung, A. Gaier, T. Lai, R. TI Demonstration of sub-millimeter wave fundamental oscillators using 35-nm InP HEMT technology SO IEEE MICROWAVE AND WIRELESS COMPONENTS LETTERS LA English DT Article DE coplanar waveguide (CPW); high electron mobility transistor (HEMT); MM-wave; monolithic microwave integrated circuit (MMIC); oscillator; sub-millimeter wave ID GHZ; BAND; AMPLIFIER AB In this letter, 254-, 314-, and 346-GHz fundamental oscillators are demonstrated. These are the highest frequency oscillators using three-terminal devices reported to date. The performance is enabled through a 35-nm InP REMT process with maximum frequency of oscillation (f(max)) of 600 GHz. These first-pass designs use coplanar waveguide (CPW) technology and include on-chip resonator and output matching. The maximum available gain (MAG) of these devices has been measured to be similar to 9.6 dB at 200 GHz. C1 Northrop Grumman Corp, Redondo Beach, CA 90278 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Radisic, V (reprint author), Northrop Grumman Corp, Redondo Beach, CA 90278 USA. EM vesna@ieee.org NR 14 TC 37 Z9 39 U1 0 U2 4 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 1531-1309 J9 IEEE MICROW WIREL CO JI IEEE Microw. Wirel. Compon. Lett. PD MAR PY 2007 VL 17 IS 3 BP 223 EP 225 DI 10.1109/LMWC.2006.890495 PG 3 WC Engineering, Electrical & Electronic SC Engineering GA 149MJ UT WOS:000245150700023 ER PT J AU Soibel, A Mansour, K Sivco, DL Cho, AY AF Soibel, A. Mansour, K. Sivco, D. L. Cho, A. Y. TI Evaluation of thermal crosstalk in quantum cascade laser arrays SO IEEE PHOTONICS TECHNOLOGY LETTERS LA English DT Article DE semiconductor laser arrays ID HIGH-POWER; ROOM-TEMPERATURE AB The continuous-wave operation, thermal crosstalk measurements, and thermal modeling of a quantum cascade (QC) laser array are presented. Measurements and thermal modeling predict that the thermal crosstalk between array elements can be minimized by improving the heat management when the spacing of neighboring laser elements is greater than 500 mu m. The output power of the demonstrated QC laser array significantly exceeds the output power of the individual lasers in the array. This shows the potential of the QC arrays as a candidate for the realization of high-power optical sources in mid-infrared (3-20 mu m) spectral range. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Lucent Technol, Bell Labs, Murray Hill, NJ 07974 USA. RP Soibel, A (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM Alexander.Soibel@jpl.nasa.gov RI Soibel, Alexander/A-1313-2007 NR 7 TC 4 Z9 4 U1 0 U2 5 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 1041-1135 J9 IEEE PHOTONIC TECH L JI IEEE Photonics Technol. Lett. PD MAR-APR PY 2007 VL 19 IS 5-8 BP 375 EP 377 DI 10.1109/LPT.2007.891888 PG 3 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA 158CJ UT WOS:000245768200040 ER PT J AU Salik, E Yu, N Maleki, L AF Salik, Ertan Yu, Nan Maleki, Lute TI An ultralow phase noise coupled optoelectronic oscillator SO IEEE PHOTONICS TECHNOLOGY LETTERS LA English DT Article DE jitter; laser noise; microwave oscillator; noise; optical fiber lasers; optical noise; oscillator phase noise; timing jitter ID LOCKED FIBER LASER; TIMING JITTER; MICROWAVE; 10GHZ AB Ultralow jitter optical pulse sources are much needed in optical communications, optical sampling, and metrology applications. We report a coupled optoelectronic oscillator employing nonpolarization-maintaining components and an erbium-doped fiber amplifier that generates 9.4-GHz microwave signals with -150-dBc/Hz phase noise at 10- to 100-kHz offset, and 2-fs jitter (integrated in 100-Hz to 100-kHz range) optical pulses. To our knowledge, this is the lowest phase noise and time jitter reported in the same frequency range for such mode-locked laser-based systems. C1 CALTECH, Jet Prop Lab, Quantum Sci & Technol Grp, Pasadena, CA 91109 USA. Calif State Polytech Univ Pomona, Dept Phys, Pomona, CA 91768 USA. RP Salik, E (reprint author), CALTECH, Jet Prop Lab, Quantum Sci & Technol Grp, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM esalik@csupomona.edu; nan.yu@jpl.nasa.gov; lute.maleki@jpl.nasa.gov NR 12 TC 46 Z9 47 U1 3 U2 17 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 1041-1135 J9 IEEE PHOTONIC TECH L JI IEEE Photonics Technol. Lett. PD MAR-APR PY 2007 VL 19 IS 5-8 BP 444 EP 446 DI 10.1109/LPT.2007.892907 PG 3 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA 158CJ UT WOS:000245768200063 ER PT J AU Tong, T Zhao, Y Delzeit, L Kashani, A Meyyappan, M Majumdar, A AF Tong, Tao Zhao, Yang Delzeit, Lance Kashani, Ali Meyyappan, M. Majumdar, Arun TI Dense, vertically aligned multiwalled carbon nanotube arrays as thermal interface materials SO IEEE TRANSACTIONS ON COMPONENTS AND PACKAGING TECHNOLOGIES LA English DT Article DE carbon nanotube (CNT); multiwalled; thermal interface material (TIM); thermo-reflectance ID CONDUCTIVITY; CONDUCTANCE AB Carbon nanotube (CNT) arrays are being considered as thermal interface materials (TIMs). Using a phase sensitive transient thermo-reflectance technique, we measure the thermal conductance of the two interfaces on each side of a vertically aligned CNT array as well as the CNT array itself. We show that the physically bonded interface by van der Waals adhesion has a conductance similar to 10(5) W/m(2) K and is the dominant resistance. We also demonstrate that by bonding the free-end CNT tips to a target surface with the help of a thin layer of indium weld, the conductance can be increased to similar to 10(6) W/m(2) K making it attractive as a TIM. C1 Univ Calif Berkeley, Dept Mech Engn, Berkeley, CA 94720 USA. Atlas Sci Inc, San Jose, CA 95120 USA. NASA, Ames Res Ctr, Ctr Nanotechnol, Moffett Field, CA 94035 USA. Lawrence Berkeley Natl Lab, Div Sci Mat, Berkeley, CA 94720 USA. RP Tong, T (reprint author), Univ Calif Berkeley, Dept Mech Engn, Berkeley, CA 94720 USA. EM ttong@me.berkeley.edu; majumdar@me.berkeley.edu NR 22 TC 182 Z9 182 U1 7 U2 58 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 1521-3331 J9 IEEE T COMPON PACK T JI IEEE Trans. Compon. Packaging Technol. PD MAR PY 2007 VL 30 IS 1 BP 92 EP 100 DI 10.1109/TCAPT.2007.892079 PG 9 WC Engineering, Manufacturing; Engineering, Electrical & Electronic; Materials Science, Multidisciplinary SC Engineering; Materials Science GA 153FV UT WOS:000245418400013 ER PT J AU Gawronski, W AF Gawronski, Wodek TI Control and pointing challenges of large antennas and telescopes SO IEEE TRANSACTIONS ON CONTROL SYSTEMS TECHNOLOGY LA English DT Article DE antenna mechanical factors; antenna transient analysis; antennas; control engineering; control systems; linear-quadratie-Gaussian control; tracking ID SEGMENTED MIRROR TELESCOPE; SPACE NETWORK ANTENNAS; RADIO-TELESCOPES; FRICTION COMPENSATION; THERMAL CONTROL; AZIMUTH-TRACK; H-INFINITY; DESIGN; SIMULATION; SYSTEMS AB Extremely. large telescopes will be constructed in the near future, and new radiotelescopes will operate at considerably higher radio frequencies; both features create significantly increased pointing accuracy requirements that have to be addressed by control system engineers. This paper presents control and pointing problems encountered during design, testing, and the operation of antennas, radiotelescopes, and optical telescopes. This collection of challenges informs of their current status, helps to evaluate their importance, and is a basis for discussion on the ways of improvement of antenna pointing accuracy. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Gawronski, W (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM wodek.k.gawronski@jpl.nasa.gov NR 86 TC 27 Z9 34 U1 0 U2 13 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 1063-6536 J9 IEEE T CONTR SYST T JI IEEE Trans. Control Syst. Technol. PD MAR PY 2007 VL 15 IS 2 BP 276 EP 289 DI 10.1109/TCST.2006.886434 PG 14 WC Automation & Control Systems; Engineering, Electrical & Electronic SC Automation & Control Systems; Engineering GA 150VN UT WOS:000245247800007 ER PT J AU Zubko, V Kaufman, YJ Burg, RI Martins, JV AF Zubko, Viktor Kaufman, Yoram J. Burg, Richard I. Martins, J. Vanderlei TI Principal component analysis of remote sensing of aerosols over oceans SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE aerosols; remote sensing; satellite applications ID REFLECTED SUNLIGHT; CLIMATE; ABSORPTION; NUMBER; INSTRUMENT; ATMOSPHERE; POLLUTION; SYSTEM; SCREE; COLOR AB We apply principal component analysis (PCA) to estimate how much information about atmospheric aerosols could be retrieved from solar-reflected radiances observed over oceans by a satellite sensor as a function of the number of wavelength bands, viewing angles, and Stokes parameters. It is assumed that our virtual satellite sensor can simultaneously perform multispectral, multiangle, and linear polarization measurements of the radiances, and the following quantities are used to vary: aerosol optical thickness, single-scattering albedo (SSA) of aerosol particles, height of the aerosol layer, aerosol model (includes size distribution parameters and optical properties), and wind speed. The real refractive index was kept constant and, therefore, is not part of the analysis. To calculate the number of significant principal components (SPCs), the cumulative percent variance rule is used, which takes into account anticipated errors of measurements. The reported results predict how much additional information can be retrieved from observations by adding more wavelength, angle, and polarization channels. For example, for the Moderate Resolution Imaging Spectroradiometer instruments (lambda > 0. 5 mu m), the number of SPCs is two to three; for Multiangle Imaging SpectroRadiometer, three to five; for Polarization and Directionality of the Earth Reflectances, five to ten; while for the future Glory/Aerosol Polarization Sensor instrument, it is 6-11 (when using eight out of its > 100 view angles). The ranges reflect view conditions, and analysis method. Our calculations show that the observations should be most sensitive to the aerosol model followed in decreasing order by optical thickness, SSA, and aerosol height. We found that there is no systematic increase in the information about aerosol starting from 10-15 view angles for unpolarized observations and 30 view angles for those with linear polarization. It is achievable with modern detectors to retrieve up to 10 and 16 SPCs from unpolarized and polarized observations, respectively. The methodology and results of our PCA can be useful for estimating the reliability of aerosol parameters retrieved from existing and future satellite observations. C1 RS Informat Syst Inc, Goddard Earth Sci Data & Informat Serv Ctr, NASA Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NASA Goddard Space Flight Ctr, Earth Observing Syst, Program Off, Greenbelt, MD 20771 USA. Univ Maryland, Joint Ctr Earth Syst Technol, Baltimore, MD 21250 USA. RP Zubko, V (reprint author), RS Informat Syst Inc, Goddard Earth Sci Data & Informat Serv Ctr, NASA Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. EM vzubko@pop600.gsfc.nasa.gov; Burg-1@nasa.gov; martins@climate.gsfc.nasa.gov NR 41 TC 16 Z9 18 U1 1 U2 9 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD MAR PY 2007 VL 45 IS 3 BP 730 EP 745 DI 10.1109/TGRS.2006.888138 PG 16 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 140ZQ UT WOS:000244545900019 ER PT J AU Smith, RS Hadaegh, FY AF Smith, R. S. Hadaegh, F. Y. TI Distributed estimation, communication and control for deep space formations SO IET CONTROL THEORY AND APPLICATIONS LA English DT Article ID VEHICLE FORMATIONS; INTERFEROMETER; INFORMATION; SYSTEMS AB Spacecraft formations in deep space give a means of implementing science instruments on a physical scale not possible with an individual spacecraft. Interferometric imaging is one application requiring a large spacecraft separation and extremely high relative position precision in order to image planets in other solar systems. Deep-space missions typically also require a high-level of autonomy, and the proposed distributed architectures for control and coordination, that are consistent with these requirements. Each spacecraft estimates the full state of the formation in order to calculate its optimal control action. Disagreements between estimates on the spacecraft lead to unanticipated dynamics and it is shown how communication may be used to ameliorate the effect of these dynamics. The relationship between the communication topology and the closed-loop system dynamics is presented. C1 Univ Calif Santa Barbara, Dept Elect & Comp Engn, Santa Barbara, CA 93106 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Smith, RS (reprint author), Univ Calif Santa Barbara, Dept Elect & Comp Engn, Santa Barbara, CA 93106 USA. EM roy@ece.ucsb.edu RI Smith, Roy/C-7340-2009 OI Smith, Roy/0000-0002-8139-4683 NR 37 TC 24 Z9 25 U1 0 U2 1 PU INSTITUTION ENGINEERING TECHNOLOGY-IET PI HERTFORD PA MICHAEL FARADAY HOUSE SIX HILLS WAY STEVENAGE, HERTFORD SG1 2AY, ENGLAND SN 1751-8644 J9 IET CONTROL THEORY A JI IET Contr. Theory Appl. PD MAR PY 2007 VL 1 IS 2 BP 445 EP 451 DI 10.1049/iet-cta:20050460 PG 7 WC Automation & Control Systems; Engineering, Electrical & Electronic; Instruments & Instrumentation SC Automation & Control Systems; Engineering; Instruments & Instrumentation GA 159BO UT WOS:000245840600002 ER PT J AU Acikmese, B Hadaegh, FY Scharf, DP Ploen, SR AF Acikmese, B. Hadaegh, F. Y. Scharf, D. P. Ploen, S. R. TI Formulation and analysis of stability for spacecraft formations SO IET CONTROL THEORY AND APPLICATIONS LA English DT Article ID DYNAMICAL-SYSTEMS; LINEAR-SYSTEMS; INPUT AB A formulation of stability for formation flying spacecraft is presented. First, a formation is defined via control interactions between the spacecraft. Then, stability is formulated on the basis of input-to-output stability with respect to a partitioning of the formation dynamics. The particular form of input-to-output stability used here is based on the peak-to-peak gain of a system from its input to its output. This formulation of stability is shown to be useful in characterising disturbance propagation in the formation as a function of the partition interconnection topology, and also in analysing the robustness of sensing, communication and control topologies. Stability analysis results are presented for hierarchical, cyclic and disturbance attenuating formations in terms of the input-to-output gains of the partitions in the formation. Finally, Lyapunov stability analysis results are provided in terms of linear matrix inequalities for a general class of formations. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Acikmese, B (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,M-S 198-326, Pasadena, CA 91109 USA. EM behcet@jpl.nasa.gov NR 27 TC 11 Z9 12 U1 0 U2 1 PU INSTITUTION ENGINEERING TECHNOLOGY-IET PI HERTFORD PA MICHAEL FARADAY HOUSE SIX HILLS WAY STEVENAGE, HERTFORD SG1 2AY, ENGLAND SN 1751-8644 J9 IET CONTROL THEORY A JI IET Contr. Theory Appl. PD MAR PY 2007 VL 1 IS 2 BP 461 EP 474 DI 10.1049/iet-cta:20050459 PG 14 WC Automation & Control Systems; Engineering, Electrical & Electronic; Instruments & Instrumentation SC Automation & Control Systems; Engineering; Instruments & Instrumentation GA 159BO UT WOS:000245840600004 ER PT J AU Garcia-Sanz, M Hadaegh, FY AF Garcia-Sanz, M. Hadaegh, F. Y. TI Load-sharing robust control of spacecraft formations: deep space and low Earth elliptic orbits SO IET CONTROL THEORY AND APPLICATIONS LA English DT Article ID SYSTEMS; DESIGN; COORDINATION AB The design of autonomous and collaborative control strategies to govern the relative distances among multiple spacecraft in formation with no ground intervention is discussed. A coordinated load-sharing control structure for formation flying and a robust methodology to control spacecraft formations under slow time-varying and uncertain parameters are the main objectives. The method shares the load according to frequency specifications and takes into account the uncertainty and the multi-input-multi-output characteristic of the system. The methodology is applied to control spacecraft in formations in both deep space and low Earth elliptic orbits. C1 Univ Publ Navarra, Automat Control & Comp Sci Dept, Pamplona 31006, Spain. CALTECH, Jet Prop Lab, NASA, Pasadena, CA 91109 USA. RP Garcia-Sanz, M (reprint author), Univ Publ Navarra, Automat Control & Comp Sci Dept, Pamplona 31006, Spain. EM mgsanz@unavarra.es NR 27 TC 3 Z9 4 U1 0 U2 2 PU INSTITUTION ENGINEERING TECHNOLOGY-IET PI HERTFORD PA MICHAEL FARADAY HOUSE SIX HILLS WAY STEVENAGE, HERTFORD SG1 2AY, ENGLAND SN 1751-8644 J9 IET CONTROL THEORY A JI IET Contr. Theory Appl. PD MAR PY 2007 VL 1 IS 2 BP 475 EP 484 DI 10.1049/iet-cta:20050395 PG 10 WC Automation & Control Systems; Engineering, Electrical & Electronic; Instruments & Instrumentation SC Automation & Control Systems; Engineering; Instruments & Instrumentation GA 159BO UT WOS:000245840600005 ER PT J AU Wang, PKC Hadaegh, FY AF Wang, P. K. C. Hadaegh, F. Y. TI Formation flying of multiple spacecraft with autonomous rendezvous and docking capability SO IET CONTROL THEORY AND APPLICATIONS LA English DT Article AB The idea of incorporating autonomous rendezvous and docking (ARVD) capability into spacecraft flying in formation is explored. The situations where it is advantageous to incorporate ARVD capability into spacecraft formations are identified. Attention is focused on various potential problems pertaining to the control of multiple spacecraft with ARVD capability. Multiple-model-based control laws for formation acquisition and ARVD are developed using generic spacecraft models. In particular, the use of such control laws for simultaneous docking of multiple spacecraft in formation acquisition and reconfiguration is studied. Various optimal formation reconfiguration problems are briefly discussed. The effectiveness of the developed control laws is studied via computer simulation using a six-spacecraft formation model. C1 Univ Calif Los Angeles, Dept Elect Engn, Los Angeles, CA 90095 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Wang, PKC (reprint author), Univ Calif Los Angeles, Dept Elect Engn, Los Angeles, CA 90095 USA. EM pkcwang@ee.ucla.edu NR 21 TC 7 Z9 8 U1 1 U2 7 PU INSTITUTION ENGINEERING TECHNOLOGY-IET PI HERTFORD PA MICHAEL FARADAY HOUSE SIX HILLS WAY STEVENAGE, HERTFORD SG1 2AY, ENGLAND SN 1751-8644 J9 IET CONTROL THEORY A JI IET Contr. Theory Appl. PD MAR PY 2007 VL 1 IS 2 BP 494 EP 504 DI 10.1049/iet-cta:20050411 PG 11 WC Automation & Control Systems; Engineering, Electrical & Electronic; Instruments & Instrumentation SC Automation & Control Systems; Engineering; Instruments & Instrumentation GA 159BO UT WOS:000245840600007 ER PT J AU Cetin, B Bikdash, M Hadaegh, FY AF Cetin, B. Bikdash, M. Hadaegh, F. Y. TI Hybrid mixed-logical linear programming algorithm for collision-free optimal path planning SO IET CONTROL THEORY AND APPLICATIONS LA English DT Article ID MANIPULATORS; AVOIDANCE AB Methods to solve collision-free fuel-optimal path- and motion-planning problems for the reconfiguration of spacecraft formations are presented. First, the motion-planning problem is formulated as a parameter optimisation problem in which the spacecraft are represented by unrotated cubes and the trajectory followed by each spacecraft is discretised in time using cubic splines. In other words, the trajectory is parameterised by the spacecraft positions and velocities at a set of waypoints. Big-M relaxation is then used to formulate the parameter optimisation as a mixed-integer linear program (MILP) whose solution can be obtained using standard MILP solvers. Several concepts are subsequently introduced to obtain the solutions more efficiently and reliably. In particular, the concept of a sequential linear program is introduced in which a sequence of closely-related linear programs are solved until a better local minimum cannot be found without 'bifurcation', that is, without qualitatively changing the nature of the solution. An example of such a change is making one spacecraft move in front of an obstacle instead of behind it. To handle these bifurcation points efficiently, the concept of a feasibility MILP (FMILP) is introduced in which the following question is answered: is there a feasible solution whose objective function value is better than that of the current bifurcation point. This is achieved by simply appending a single linear constraint to the set of constraints. A bisection search can be applied to the cost using FMILPs to further speed the proposed method. The method was applied to two standard tests of motion planning with collision avoidance such as swapping (using minimum fuel and along the major diagonals) the positions of eight spacecraft located at the corners of a cube. Preliminary simulations show significant improvement in efficiency by at least one order of magnitude. C1 N Carolina Agr & Tech State Univ, Dept Elect & Comp Engn, Greensboro, NC 27411 USA. CALTECH, Jet Prop Lab, Pasadena, CA USA. RP Cetin, B (reprint author), N Carolina Agr & Tech State Univ, Dept Elect & Comp Engn, Greensboro, NC 27411 USA. EM bcetin@ncat.edu NR 26 TC 13 Z9 17 U1 0 U2 6 PU INSTITUTION ENGINEERING TECHNOLOGY-IET PI HERTFORD PA MICHAEL FARADAY HOUSE SIX HILLS WAY STEVENAGE, HERTFORD SG1 2AY, ENGLAND SN 1751-8644 J9 IET CONTROL THEORY A JI IET Contr. Theory Appl. PD MAR PY 2007 VL 1 IS 2 BP 522 EP 531 DI 10.1049/iet-cta:20050432 PG 10 WC Automation & Control Systems; Engineering, Electrical & Electronic; Instruments & Instrumentation SC Automation & Control Systems; Engineering; Instruments & Instrumentation GA 159BO UT WOS:000245840600010 ER PT J AU Wolf, DA AF Wolf, David A. TI NASA space based research: Challenges and benefits for tissue engineering. SO IN VITRO CELLULAR & DEVELOPMENTAL BIOLOGY-ANIMAL LA English DT Meeting Abstract C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. EM david.a.wolf@nasa.gov NR 0 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER PI NEW YORK PA 233 SPRING STREET, NEW YORK, NY 10013 USA SN 1071-2690 J9 IN VITRO CELL DEV-AN JI In Vitro Cell. Dev. Biol.-Anim. PD SPR PY 2007 VL 43 SU S BP S1 EP S1 PG 1 WC Cell Biology; Developmental Biology SC Cell Biology; Developmental Biology GA 187UF UT WOS:000247873400002 ER PT J AU Yen, E Chu, IWM AF Yen, Ester Chu, I-Wen Mike TI Relaxing instance boundaries for the search of splitting points of numerical attributes in classification trees SO INFORMATION SCIENCES LA English DT Article DE classification tree; decision trees; heuristic partition method; numerical attributes; splitting point; relaxation of instance boundaries; data mining ID DISCRETIZATION AB We propose a simple heuristic partition method (HPM) of classification tree to improve efficiency in the search for splitting points of numerical attributes. The proposal is motivated by the idea that the selection process of candidates in the splitting point selection can be made more flexible as to achieve a faster computation while retaining classification accuracy. We compare the performance of the HPM against Fayyad's method, as the latter is the improved version of the standard C4.5 algorithm on the search of splitting points. We demonstrate that HPM is more efficient, in some cases by as much as 50%, while producing essentially the same classification for six different data sets. Our result supports the relaxation of instance boundaries (RIB) as a valid approach that can be explored to achieve more efficient computations. (c) 2006 Elsevier Inc. All rights reserved. C1 Univ London Imperial Coll Sci Technol & Med, London SW7 2AY, England. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Yen, E (reprint author), Univ London Imperial Coll Sci Technol & Med, London SW7 2AY, England. EM ester_yen@yahoo.com NR 36 TC 8 Z9 9 U1 0 U2 0 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0020-0255 J9 INFORM SCIENCES JI Inf. Sci. PD MAR 1 PY 2007 VL 177 IS 5 BP 1276 EP 1289 DI 10.1016/j.ins.2006.08.014 PG 14 WC Computer Science, Information Systems SC Computer Science GA 134CL UT WOS:000244060100010 ER PT J AU Hatamleh, O Lyons, J Forman, R AF Hatamleh, Omar Lyons, Jed Forman, Royce TI Laser and shot peening effects on fatigue crack growth in friction stir welded 7075-T7351 aluminum alloy joints SO INTERNATIONAL JOURNAL OF FATIGUE LA English DT Article DE friction stir welding; laser peening; shot peening; fatigue crack growth ID RESIDUAL-STRESS; WELDING SPEED; MICROSTRUCTURE; BEHAVIOR; PROPAGATION AB The influence of shot and laser peening on the fatigue crack growth behavior of friction stir welded (FSW) aluminum alloy (AA) 7075T7351 sheets was investigated. The alterations resulting from this surface modification on the fatigue crack growth of FSW were characterized and evaluated for two different crack configurations. A systematic investigation of the various peening effects indicated a significant decrease in fatigue crack growth rates resulting from using laser peening compared with native welded and unwelded specimens. In contrast, shot peened specimens did not result in a significant reduction in fatigue crack growth. The fatigue striation spacings for the laser peened specimens were assessed and found to be small compared with the unpeened, and shot peened specimens. The reduction in striation spacing indicates a slower fatigue crack growth rate and is partially attributed to the deeper compressive residual stresses induced by the laser peening. Published by Elsevier Ltd. C1 NASA, Lyndon B Johnson Space Ctr, Struct & Dynam Branch, Houston, TX 77058 USA. Univ S Carolina, Dept Mech Engn, Columbia, SC 29208 USA. NASA, Lyndon B Johnson Space Ctr, Mat & Proc Branch, Houston, TX 77058 USA. RP Hatamleh, O (reprint author), NASA, Lyndon B Johnson Space Ctr, Struct & Dynam Branch, Houston, TX 77058 USA. EM omar.hatamleh-1@nasa.gov NR 41 TC 62 Z9 66 U1 5 U2 45 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0142-1123 J9 INT J FATIGUE JI Int. J. Fatigue PD MAR PY 2007 VL 29 IS 3 BP 421 EP 434 DI 10.1016/j.ijfatigue.2006.05.007 PG 14 WC Engineering, Mechanical; Materials Science, Multidisciplinary SC Engineering; Materials Science GA 134CW UT WOS:000244061200004 ER PT J AU Mavriplis, DJ Aftosmis, MJ Berger, M AF Mavriplis, Dimitri J. Aftosmis, Michael J. Berger, Marsha TI High resolution aerospace applications using the NASA Columbia supercomputer SO INTERNATIONAL JOURNAL OF HIGH PERFORMANCE COMPUTING APPLICATIONS LA English DT Article DE NASA Columbia; SGI Altix; scalability; hybrid programming; unstructured; computational fluid dynamics; OpenMP ID NAVIER-STOKES EQUATIONS; UNSTRUCTURED MESHES; MULTIGRID SOLVER AB This paper focuses on the parallel performance of two high-performance aerodynamic simulation packages on the newly installed NASA Columbia supercomputer. These packages include both a high-fidelity, unstructured, Reynolds-averaged Navier-Stokes solver, and a fully-automated inviscid flow package for cut-cell Cartesian grids. The complementary combination of these two simulation codes enables high-fidelity characterization of aerospace vehicle design performance over the entire flight envelope through extensive parametric analysis and detailed simulation of critical regions of the flight envelope. Both packages are industrial-level codes designed for complex geometry and incorporate customized multigrid solution algorithms. The performance of these codes on Columbia is examined using both MPI and OpenMP and using both the NUMAlink and InfiniBand interconnect fabrics. Numerical results demonstrate good scalability on up to 2016 CPUs using the NUMAlink4 interconnect, with measured computational rates in the vicinity of 3 TFLOP/s, while InfiniBand showed some performance degradation at high CPU counts, particularly with multigrid. Nonetheless, the results are encouraging enough to indicate that larger test cases using combined MPI/OpenMP communication should scale well on even more processors. C1 Univ Wyoming, Dept Mech Engn, Laramie, WY 82071 USA. NASA, Adv Supercomp Div, Ames Res Ctr, Moffett Field, CA 94035 USA. NYU, Courant Inst, Dept Comp Sci, New York, NY 10012 USA. RP Mavriplis, DJ (reprint author), Univ Wyoming, Dept Mech Engn, Laramie, WY 82071 USA. EM BERGER@CIMS.NYU.EDU NR 25 TC 6 Z9 6 U1 0 U2 2 PU SAGE PUBLICATIONS LTD PI LONDON PA 1 OLIVERS YARD, 55 CITY ROAD, LONDON EC1Y 1SP, ENGLAND SN 1094-3420 J9 INT J HIGH PERFORM C JI Int. J. High Perform. Comput. Appl. PD SPR PY 2007 VL 21 IS 1 BP 106 EP 126 DI 10.1177/1094342006074872 PG 21 WC Computer Science, Hardware & Architecture; Computer Science, Interdisciplinary Applications; Computer Science, Theory & Methods SC Computer Science GA 136HV UT WOS:000244214100011 ER PT J AU Edwards, CD AF Edwards, Charles D. TI Relay communications for Mars exploration SO INTERNATIONAL JOURNAL OF SATELLITE COMMUNICATIONS AND NETWORKING LA English DT Article ID MISSION AB Telecommunication is an essential and challenging aspect of planetary exploration. For Mars landers, the constraints of mass, volume, power and energy typically limit their communications capabilities on the long-distance link back to Earth. By deploying relay spacecraft in Martian orbit, these landers can achieve much greater data return and can obtain contact opportunities at times when Earth is not in view. Currently, both NASA and European Space Agency (ESA) have pursued this strategy, deploying relay payloads on their Mars science orbiters. This relay infrastructure has significantly benefited the science return from the 2003 Mars Exploration Rovers and is poised to support the Phoenix Lander and Mars Science Laboratory missions later this decade. Longer-term plans call for continued growth in relay capability, greatly increasing data return from the Martian surface to enable exciting new Mars exploration concepts and advance our understanding of our planetary neighbour. Copyright (c) 2007 John Wiley & Sons, Ltd. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Edwards, CD (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 301-340, Pasadena, CA 91109 USA. EM chad.edwards@jpl.nasa.gov NR 12 TC 15 Z9 15 U1 0 U2 1 PU JOHN WILEY & SONS LTD PI CHICHESTER PA THE ATRIUM, SOUTHERN GATE, CHICHESTER PO19 8SQ, W SUSSEX, ENGLAND SN 1542-0973 J9 INT J SATELL COMM N JI Int. J. Satell. Commun. Netw. PD MAR-APR PY 2007 VL 25 IS 2 BP 111 EP 145 DI 10.1002/sat.871 PG 35 WC Engineering, Aerospace; Telecommunications SC Engineering; Telecommunications GA 145YQ UT WOS:000244902100002 ER PT J AU Sun, J Gao, J Shambayati, S Modiano, E AF Sun, Jun Gao, Jay Shambayati, Shervin Modiano, Eytan TI Ka-band link optimization with rate adaptation for Mars and lunar communications SO INTERNATIONAL JOURNAL OF SATELLITE COMMUNICATIONS AND NETWORKING LA English DT Article DE Ka-band; satellite communications; link optimization; rate adaptation ID ACTS PROPAGATION EXPERIMENT; PREDICTION MODEL COMPARISONS; MANAGEMENT AB On-going development of Ka-band capability for the Deep Space Networks (DSN) will radically increase the bandwidth available to support advanced mission concepts envisioned for future robotic as well as human exploration of Mars and beyond. While Ka-band links can operate at much higher data rate than X-band, they are much more susceptible to fluctuating weather conditions and manifest a significant trade-off between throughput and availability. If the operating point is fixed, the maximum average throughput for deep space Ka-band link is achieved at about 80% availability, i.e. weather-related outages will occur about 20% of the time. Low availability increases the complexity of space mission operation, while higher availability would require additional link margins that lowers the overall throughput. To improve this fundamental throughput-availability trade-off, data rate adaptation based on real-time observation of the channel condition is necessary. In this paper, we model the Ka-band channel using a Markov process to capture the impact of the temporal correlation in weather conditions. We then develop a rate adaptation algorithm to optimize the data rate based on real time feedback on the measured channel conditions. Our algorithm achieves both higher throughput and link availability as compared to the constant rate scheme presently in use. Copyright (c) 2007 John Wiley & Sons, Ltd. C1 MIT, Cambridge, MA 02139 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Sun, J (reprint author), MIT, 77 Massachusetts Ave, Cambridge, MA 02139 USA. EM junsun@mit.edu NR 14 TC 4 Z9 4 U1 0 U2 4 PU JOHN WILEY & SONS LTD PI CHICHESTER PA THE ATRIUM, SOUTHERN GATE, CHICHESTER PO19 8SQ, W SUSSEX, ENGLAND SN 1542-0973 J9 INT J SATELL COMM N JI Int. J. Satell. Commun. Netw. PD MAR-APR PY 2007 VL 25 IS 2 BP 147 EP 165 DI 10.1002/sat.869 PG 19 WC Engineering, Aerospace; Telecommunications SC Engineering; Telecommunications GA 145YQ UT WOS:000244902100003 ER PT J AU Wood, L Ivancic, W Hodgson, D Miller, E Conner, B Lynch, S Jackson, C Curiel, AD Cooke, D Shell, D Walke, J Stewart, D AF Wood, L. Ivancic, W. Hodgson, D. Miller, E. Conner, B. Lynch, S. Jackson, C. Curiel, A. da Silva Cooke, D. Shell, D. Walke, J. Stewart, D. TI Using Internet nodes and routers onboard satellites SO INTERNATIONAL JOURNAL OF SATELLITE COMMUNICATIONS AND NETWORKING LA English DT Article DE Internet; router; UK-DMC; satellite; HDLC; frame relay; IP; UDP ID ORBIT AB An Internet router was integrated into the UK-DMC remote-sensing satellite as a secondary experimental payload. This commercial product has been orbiting in space for over three years. We describe the integration of the router and satellite and the successful on-orbit testing of the router, which took place using the Virtual Mission Operations Center (VMOC) application as part of a larger systems internetworking exercise. Placing this Cisco router in Low Earth Orbit (CLEO) onboard a small satellite is one step towards extending the terrestrial networking model to the near-Earth space environment as part of a merged space-ground architecture. Copyright (c) 2007 John Wiley & Sons, Ltd. C1 Cisco Syst Global Govt Solut Grp, London, England. NASA, Glenn Res Ctr, Cleveland, OH USA. Univ Surrey, DMC Int Imaging, Guildford GU2 5XH, Surrey, England. Univ Surrey, Surrey Satellite Technol Ltd, Guildford GU2 5XH, Surrey, England. USAF, Space Battlelab, Schriever AFB, CO USA. Universal Space Network Inc, Horsham, PA USA. Cisco Syst Govt Serv Unit, Richfield, OH USA. Verizon Fed Network Syst, Cleveland, OH USA. RP Wood, L (reprint author), 11 New Sq Pk, Feltham TW14 8HA, Middx, England. EM lwood@cisco.com; wivancic@grc.nasa.gov; d.hodgson@dmcii.com; eric.miller@gd-ais.com; brett.conner@afosr.af.mil; lynch@uspacenet.com; c.jackson@sstl.co.uk; a.da-silva-curiel@sstl.co.uk; d.cooke@sstl.co.uk; dshellwireless@gmail.com; jon.walke@gd-ais.com; dstewart@grc.nasa.gov NR 27 TC 9 Z9 12 U1 0 U2 4 PU JOHN WILEY & SONS LTD PI CHICHESTER PA THE ATRIUM, SOUTHERN GATE, CHICHESTER PO19 8SQ, W SUSSEX, ENGLAND SN 1542-0973 J9 INT J SATELL COMM N JI Int. J. Satell. Commun. Netw. PD MAR-APR PY 2007 VL 25 IS 2 BP 195 EP 216 DI 10.1002/sat.870 PG 22 WC Engineering, Aerospace; Telecommunications SC Engineering; Telecommunications GA 145YQ UT WOS:000244902100005 ER PT J AU Menon, PK Sweriduk, GD Bowers, AH AF Menon, P. K. Sweriduk, G. D. Bowers, A. H. TI Study of near-optimal endurance-maximizing periodic cruise trajectories SO JOURNAL OF AIRCRAFT LA English DT Article; Proceedings Paper CT AIAA Guidance, Navigation and Control Conference CY SEP 15-18, 2005 CL San Francisco, CA SP AIAA ID AIRCRAFT AB A near-optimal periodic solution to the maximum-endurance cruise problem is investigated Point-mass models are developed for different types of aircraft. Energy-state-based methods are used to determine minimum-fuel climb and maximum-endurance descent schedules in the altitude-airspeed plane, which are then pieced together with transition arcs to form the periodic cruise solution. A trajectory-tracking controller is designed to make the point-mass models track the periodic cruise trajectories. The tracking controller is designed using the feedback linearization methodology. Closed-loop simulations are then used to compute the fuel consumption resulting from the use of periodic trajectories. These values are compared with the steady-state, optimal-endurance cruise fuel consumption values. For a model of the F/A-18 aircraft, it was found that savings of about 17% could be realized if the engines can be turned off when the aircraft is not on the climb schedule. However, if the throttle cannot be set below flight idle, the periodic cruise trajectory is found to produce worse performance than the steady-state cruise. Simulations with a model of an F-4 in periodic cruise with nonzero minimum throttle did show a modest improvement over the steady-state cruise performance, but only by 2.7%. C1 Optimal Synth Inc, Palo Alto, CA 94303 USA. NASA, Dryden Flight Res Ctr, Edwards AFB, CA 93523 USA. RP Menon, PK (reprint author), Optimal Synth Inc, Palo Alto, CA 94303 USA. NR 21 TC 1 Z9 1 U1 0 U2 3 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0021-8669 J9 J AIRCRAFT JI J. Aircr. PD MAR-APR PY 2007 VL 44 IS 2 BP 393 EP 398 DI 10.2514/1.20305 PG 6 WC Engineering, Aerospace SC Engineering GA 155YP UT WOS:000245615000005 ER PT J AU Parker, PA Finley, TD AF Parker, Peter A. Finley, Tom D. TI Advancements in aircraft model force and attitude instrumentation by integrating statistical methods SO JOURNAL OF AIRCRAFT LA English DT Article; Proceedings Paper CT United States Air Force T&E Days Conference 2005 CY DEC 06-08, 2005 CL Nashville, TN ID PROFILES AB Applying statistical methods in conjunction with instrumentation expertise has resulted in a dramatic reduction in calibration time and expense, while simultaneously improving the calibration quality. In this paper, we illustrate the application of response surface methodology and statistical quality control to two quintessential instruments used in aeronautical wind-tunnel experiments, namely, the force balance and the triaxial accelerometer. We emphasize the benefits that have been achieved by integrating the statistical design with the mechanical calibration system. For both instruments, we discuss the development of an experimental design that accommodates physics-based constraints and highlight an innovative calibration apparatus. As a result of reduced calibration time, the frequency of calibration can be increased, which enables the monitoring of instrument stability over time. Throughout the calibration process, we emphasize efficient allocation of experimental resources to achieve the calibration requirements. C1 NASA, Langley Res Ctr, Aeronaut Syst Engn Branch, Hampton, VA 23681 USA. RP Parker, PA (reprint author), NASA, Langley Res Ctr, Aeronaut Syst Engn Branch, Hampton, VA 23681 USA. NR 28 TC 6 Z9 7 U1 0 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0021-8669 J9 J AIRCRAFT JI J. Aircr. PD MAR-APR PY 2007 VL 44 IS 2 BP 436 EP 443 DI 10.2514/1.23060 PG 8 WC Engineering, Aerospace SC Engineering GA 155YP UT WOS:000245615000010 ER PT J AU Rumsey, CL AF Rumsey, Christopher L. TI Reynolds-averaged Navier-Stokes analysis of zero efflux flow control over a hump model SO JOURNAL OF AIRCRAFT LA English DT Article; Proceedings Paper CT AIAA 44th Aerospace Sciences Meeting and Exhibit CY JAN 09-12, 2006 CL Reno, NV SP AIAA ID WALL-MOUNTED HUMP; NUMERICAL-SIMULATION; TURBULENT-FLOW; SEPARATION AB The unsteady flow over a hump model with zero efflux oscillatory flow control is modeled computationally using the unsteady Reynolds-averaged Navier-Stokes equations. Three different turbulence models produce similar results and do a reasonably good job predicting the general character of the unsteady surface pressure coefficients during the forced cycle. However, the turbulent shear stresses are underpredicted in magnitude inside the separation bubble, and the computed results predict too large a (mean) separation bubble compared with experiment. These missed predictions are consistent with earlier steady-state results using no-flow control and steady suction, from a 2004 CFD validation workshop for synthetic jets. C1 NASA, Langley Res Ctr, Computat Aerosci Branch, Hampton, VA 23681 USA. RP Rumsey, CL (reprint author), NASA, Langley Res Ctr, Computat Aerosci Branch, Mail Stop 128, Hampton, VA 23681 USA. EM c.l.rumsey@nasa.gov NR 27 TC 6 Z9 6 U1 0 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0021-8669 J9 J AIRCRAFT JI J. Aircr. PD MAR-APR PY 2007 VL 44 IS 2 BP 444 EP 452 DI 10.2514/1.23514 PG 9 WC Engineering, Aerospace SC Engineering GA 155YP UT WOS:000245615000011 ER PT J AU Yeo, H Johnson, W AF Yeo, Hyeonsoo Johnson, Wayne TI Aeromechanics analysis of a heavy lift slowed-rotor compound helicopter SO JOURNAL OF AIRCRAFT LA English DT Article AB A heavy lift slowed-rotor tandem compound helicopter was designed as a part of the NASA heavy lift rotorcraft systems investigation. The vehicle is required to carry 120 passengers over a range of 1200 nautical miles and cruise at 350 knots at an altitude of 30,000 feet. The basic size of the helicopter was determined by the United States Army Aeroflightdynamics Directorate's design code RotorCraft. Then performance, loads, and stability analyses were conducted with the Comprehensive Analytical Model of Rotorcraft Aerodynamics and Design II. Blade structural design (blade inertial and structural properties) was carried out using the loading condition from the Comprehensive Analytical Model of Rotorcraft Aerodynamics and Design II. A rotor parametric study was conducted to investigate the effects of the twist, collective, tip speed, and taper on aircraft performance. Designs were also developed for alternate missions to explore the influence of the design condition on performance. C1 NASA, Ames Res Ctr, Aeroflightdynam Directorate, AMRDEC,USA,Res Dev & Engn Command, Moffett Field, CA 94035 USA. NASA, Ames Res Ctr, Flight Vehicle Res & Technol Div, Moffett Field, CA 94035 USA. RP Yeo, H (reprint author), NASA, Ames Res Ctr, Aeroflightdynam Directorate, AMRDEC,USA,Res Dev & Engn Command, MS 215-1, Moffett Field, CA 94035 USA. EM hsyeo@mail.arc.nasa.gov NR 9 TC 7 Z9 10 U1 0 U2 3 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0021-8669 J9 J AIRCRAFT JI J. Aircr. PD MAR-APR PY 2007 VL 44 IS 2 BP 501 EP 508 DI 10.2514/1.23905 PG 8 WC Engineering, Aerospace SC Engineering GA 155YP UT WOS:000245615000017 ER PT J AU McAdams, DA Comella, D AF McAdams, Daniel A. Comella, David TI Exploring effective methods for simulating damaged structures with geometric variation: Toward intelligent failure detection SO JOURNAL OF APPLIED MECHANICS-TRANSACTIONS OF THE ASME LA English DT Article ID VIBRATION; BEAM; CRACK; MODEL AB Inaccuracies in the modeling assumptions about the distributional characteristics of the monitored signatures have been shown to cause frequent false positives in vehicle monitoring systems for high-risk aerospace applications. To enable the development of robust fault detection methods, this work explores the deterministic as well as variational characteristics of failure signatures. Specifically, we explore the combined impact of crack damage and manufacturing variation on the vibrational characteristics of beams. The transverse vibration and associated eigenfrequencies of the beams are considered. Two different approaches are used to model beam vibrations with and without crack damage. The first approach uses a finite difference approach to enable the inclusion of both cracks and manufacturing variation. The crack model used with both approaches is based on a localized decrease in the Young's modulus. The second approach uses Myklestad's method to evaluate the effects of cracks and manufacturing variation. Using both beam models, Monte Carlo simulations are used to explore the impacts of manufacturing variation on damaged and undamaged beams. Derivations are presented for both models. Conclusions are presented on the choice of modeling techniques to define crack damage, and its impact on the monitored signal, followed by conclusions about the distributional characteristics of the monitored signatures when exposed to random manufacturing variations. C1 Univ Missouri, Dept Mech & Aerosp Engn, Rolla, MO 65409 USA. NASA, Complex Syst Design Grp, Intelligent Syst Div, Ames Res Ctr, Moffett Field, CA 94035 USA. RP McAdams, DA (reprint author), Univ Missouri, Dept Mech & Aerosp Engn, Rolla, MO 65409 USA. EM dmcadams@umr.edu NR 48 TC 4 Z9 4 U1 0 U2 2 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA THREE PARK AVE, NEW YORK, NY 10016-5990 USA SN 0021-8936 J9 J APPL MECH-T ASME JI J. Appl. Mech.-Trans. ASME PD MAR PY 2007 VL 74 IS 2 BP 191 EP 202 DI 10.1115/1.2188535 PG 12 WC Mechanics SC Mechanics GA 150NN UT WOS:000245223600003 ER PT J AU Chiriaco, M Chepfer, H Minnis, P Haeffelin, M Platnick, S Baumgardner, D Dubuisson, P McGill, M Noel, V Pelon, J Spangenberg, D Sun-Mack, S Wind, G AF Chiriaco, M. Chepfer, H. Minnis, P. Haeffelin, M. Platnick, S. Baumgardner, D. Dubuisson, P. McGill, M. Noel, V. Pelon, J. Spangenberg, D. Sun-Mack, S. Wind, G. TI Comparison of CALIPSO-like, LaRC, and MODIS retrievals of ice-cloud properties over SIRTA in France and Florida during CRYSTAL-FACE SO JOURNAL OF APPLIED METEOROLOGY AND CLIMATOLOGY LA English DT Article ID SINGLE-SCATTERING PROPERTIES; SOLAR RADIATIVE-TRANSFER; CIRRUS CLOUD; LIGHT-SCATTERING; RADIANCE MEASUREMENTS; DIELECTRIC PARTICLES; OPTICAL-THICKNESS; LIQUID WATER; MU-M; LIDAR AB This study compares cirrus-cloud properties and, in particular, particle effective radius retrieved by a Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO)-like method with two similar methods using Moderate-Resolution Imaging Spectroradiometer ( MODIS), MODIS Airborne Simulator (MAS), and Geostationary Operational Environmental Satellite imagery. The CALIPSO-like method uses lidar measurements coupled with the split-window technique that uses the infrared spectral information contained at the 8.65-, 11.15-, and 12.05-mu m bands to infer the microphysical properties of cirrus clouds. The two other methods, using passive remote sensing at visible and infrared wavelengths, are the operational MODIS cloud products (using 20 spectral bands from visible to infrared, referred to by its archival product identifier MOD06 for MODIS Terra) and MODIS retrievals performed by the Clouds and the Earth's Radiant Energy System (CERES) team at Langley Research Center (LaRC) in support of CERES algorithms (using 0.65-, 3.75-, 10.8-, and 12.05-mu m bands); the two algorithms will be referred to as the MOD06 and LaRC methods, respectively. The three techniques are compared at two different latitudes. The midlatitude ice-clouds study uses 16 days of observations at the Palaiseau ground-based site in France [Site Instrumental de Recherche par Teledetection Atmospherique (SIRTA)], including a ground-based 532-nm lidar and the MODIS overpasses on the Terra platform. The tropical ice-clouds study uses 14 different flight legs of observations collected in Florida during the intensive field experiment known as the Cirrus Regional Study of Tropical Anvils and Cirrus Layers-Florida Area Cirrus Experiment (CRYSTAL-FACE), including the airborne cloud-physics lidar and the MAS. The comparison of the three methods gives consistent results for the particle effective radius and the optical thickness but discrepancies in cloud detection and altitudes. The study confirms the value of an active remote sensing method (CALIPSO like) for the study of subvisible ice clouds, in both the midlatitudes and Tropics. Nevertheless, this method is not reliable in optically very thick tropical ice clouds, because of their particular microphysical properties. C1 Ecole Polytech, IPSL, Meteorol Dynam Lab, F-91128 Palaiseau, France. NASA, Langley Res Ctr, Hampton, VA 23665 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Nacl Autonoma Mexico, Mexico City 04510, DF, Mexico. Univ Littoral, ELICO, Dunkerque, France. IPSL, Serv Aeron, Paris, France. AS&M Inc, Hampton, VA USA. SAIC, Hampton, VA USA. SSAI, Lanham, MD USA. RP Chiriaco, M (reprint author), Ecole Polytech, IPSL, Meteorol Dynam Lab, F-91128 Palaiseau, France. EM chiriaco@lmd.polytechnique.fr RI McGill, Matthew/D-8176-2012; Noel, Vincent/C-3702-2013; Platnick, Steven/J-9982-2014; Minnis, Patrick/G-1902-2010 OI Noel, Vincent/0000-0001-9494-0340; Platnick, Steven/0000-0003-3964-3567; Minnis, Patrick/0000-0002-4733-6148 NR 58 TC 20 Z9 20 U1 0 U2 3 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 1558-8424 J9 J APPL METEOROL CLIM JI J. Appl. Meteorol. Climatol. PD MAR PY 2007 VL 46 IS 3 BP 249 EP 272 DI 10.1175/JAM2435.1 PG 24 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 155RP UT WOS:000245595900001 ER PT J AU Maslov, AV Ning, CZ AF Maslov, A. V. Ning, C. Z. TI Interpretation of distributed-feedback-laser spectrum using reflection properties of Bloch waves SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID THRESHOLD AB We demonstrate that the phase and amplitude of the reflection coefficient for Bloch waves can be useful tools in understanding and predicting the spectral characteristics of distributed-feedback lasers. We further apply the Bloch wave formalism for engineering the asymmetry of the spectral response with respect to the gap through a judicious termination of the laser facets. (c) 2007 American Institute of Physics. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Arizona State Univ, Dept Elect Engn, Tempe, AZ 85287 USA. RP Maslov, AV (reprint author), Canon Dev Amer Inc, Irvine, CA USA. EM alexey.maslov@gmail.com RI Maslov, Alexey/E-5158-2011; Ning, C. Z./D-4699-2009 OI Maslov, Alexey/0000-0002-7835-2474; Ning, C. Z./0000-0003-4583-8889 NR 11 TC 1 Z9 1 U1 0 U2 3 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD MAR 1 PY 2007 VL 101 IS 5 AR 053117 DI 10.1063/1.2437575 PG 5 WC Physics, Applied SC Physics GA 146PB UT WOS:000244945400017 ER PT J AU Twigg, ME Bassim, ND Mastro, MA Eddy, CR Henry, RL Culbertson, JC Holm, RT Neudeck, P Powell, JA Trunek, AJ AF Twigg, M. E. Bassim, N. D. Mastro, M. A. Eddy, C. R., Jr. Henry, R. L. Culbertson, J. C. Holm, R. T. Neudeck, P. Powell, J. A. Trunek, A. J. TI Strain relief and dislocation motion in III-nitride films grown on stepped and step-free 4H-SiC mesas SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID GAN; STRESS; LAYERS; STATE AB The impetus for dislocation motion in thin films is generally understood in terms of Peach-Koehler forces. For the case of III-nitride films grown on step-free 4H-SiC mesas, however, it is the gradient of the strain energy from the mesa edge that is capable of driving misfit dislocations. Using the strain profile as a function of the distance from the mesa edge and the line tension of the c-plane threading arms, we have calculated the excess stress driving the half loop from the mesa edge into the mesa interior. We have also compared the half-loop excess stress with the excess stress driving the tilt of threading edge dislocations, which has been proposed as one of the principal strain relief mechanisms in III-nitride films. The excess stress driving c-plane half loops ranges from a few 1000 MPa at the mesa edge to few 100 MPa towards the mesa interior, while the excess stress driving the tilt of threading edge dislocations is in excess of 20 000 MPa. The greater excess stress driving dislocation tilt, however, does not dominate strain relief for III-nitride films on step-free SiC mesas due to the difficulty in nucleating threading dislocations in the absence of interfacial steps. (c) 2007 American Institute of Physics. C1 USN, Res Lab, Washington, DC 20375 USA. NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. OAI, Cleveland, OH 44135 USA. Sest Inc, Cleveland, OH 44135 USA. RP Twigg, ME (reprint author), USN, Res Lab, Washington, DC 20375 USA. EM twigg@estd.nrl.navy.mil NR 20 TC 4 Z9 4 U1 3 U2 7 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD MAR 1 PY 2007 VL 101 IS 5 AR 053509 DI 10.1063/1.2435068 PG 6 WC Physics, Applied SC Physics GA 146PB UT WOS:000244945400035 ER PT J AU Zhan, C Lee, J Yin, S Ruffin, P Grant, J AF Zhan, Chun Lee, Jon Yin, Stuart Ruffin, Paul Grant, Joseph TI Photoenhanced polarization mode separated fiber Bragg gratings inscribed by femtosecond laser SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID WRITTEN WAVE-GUIDES; OPTICAL-FIBERS; PHASE MASK; SENSORS; STRESS; TEMPERATURE; RADIATION; SILICA; STRAIN AB In this paper, we report the fabrication of photoenhanced polarization mode separated fiber Bragg gratings (FBGs) in polarization maintaining (PM) fibers using IR femtosecond laser illumination. The separation of the Bragg resonant wavelengths between the two polarization modes is as large as 1.78 nm due to the photoenhanced birefringence effect generated by the strong ultrashort laser pulses. This large polarization mode separation solves one of the major problems of the conventional PM Bragg gratings (i.e., the narrow spacing or even the partial spectral overlap between spectra of the two polarization eigenmodes) and substantially enhances the multiparameter sensing capability of FBGs by offering a wider sensing range and higher discrimination. Furthermore, the high thermal stability of FBGs (up to 1000 degrees C for silica fibers) inscribed by IR femtosecond lasers provides for multiparameter sensing in harsh, high temperature environments. (c) 2007 American Institute of Physics. C1 Penn State Univ, Dept Elect Engn, University Pk, PA 16802 USA. USA, Aviat & Missile Command, Redstone Arsenal, AL 35898 USA. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Zhan, C (reprint author), Penn State Univ, Dept Elect Engn, University Pk, PA 16802 USA. EM cuz103@psu.edu NR 20 TC 4 Z9 5 U1 0 U2 2 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0021-8979 EI 1089-7550 J9 J APPL PHYS JI J. Appl. Phys. PD MAR 1 PY 2007 VL 101 IS 5 AR 053110 DI 10.1063/1.2437583 PG 7 WC Physics, Applied SC Physics GA 146PB UT WOS:000244945400010 ER PT J AU Tuday, EC Meck, JV Nyhan, D Shoukas, AA Berkowitz, DE AF Tuday, Eric C. Meck, Janice V. Nyhan, Daniel Shoukas, Artin A. Berkowitz, Dan E. TI Microgravity-induced changes in aortic stiffness and their role in orthostatic intolerance SO JOURNAL OF APPLIED PHYSIOLOGY LA English DT Article DE microgravity; arterial compliance; hindlimb unweighting; resistance to venous return ID SIMULATED MICROGRAVITY; ARTERIAL STIFFNESS; VASCULAR-RESISTANCE; CROSS-LINKS; RAT; SPACEFLIGHT; PATHOPHYSIOLOGY; HYPOTENSION; MECHANISMS; PRESSURE AB Microgravity (mu G)- induced orthostatic intolerance (OI) in astronauts is characterized by a marked decrease in cardiac output ( CO) in response to an orthostatic stress. Since CO is highly dependent on venous return, alterations in the resistance to venous return (RVR) may be important in contributing to OI. The RVR is directly dependent on arterial compliance (C-a), where aortic compliance (C-ao) contributes up to 60% of C-a. We tested the hypothesis that mu G-induced changes in C-a may represent a protective mechanism against OI. A retrospective analysis on hemodynamic data collected from astronauts after 5- to 18-day spaceflight missions revealed that orthostatically tolerant (OT) astronauts showed a significant decrease in C-a after spaceflight, while OI astronauts showed a slight increase in C-a. A ground-based animal model simulating mu G, hindlimb-unweighted rats, was used to explore this phenomenon. Two independent assessments of C-ao, in vivo pulse wave velocity (PWV) of the thoracic aorta and in vitro pressure-diameter squared relationship (PDSR) measurements of the excised thoracic aorta, were determined. PWV showed a significant increase in aortic stiffness compared with control, despite unchanged blood pressures. This increase in aortic stiffness was confirmed by the PDSR analysis. Thus both actual mu G in humans and simulated mu G in rats induces changes in C-ao. The difference in C-a in OT and OI astronaut suggests that the mu G-induced decrease in C-a is a protective adaptation to spaceflight that reduces the RVR and allows for the maintenance of adequate CO in response to an orthostatic stress. C1 Johns Hopkins Univ, Sch Med, Dept Biomed Engn, Baltimore, MD 21205 USA. Johns Hopkins Univ, Sch Med, Dept Anesthesiol & Crit Care Med, Baltimore, MD 21205 USA. NASA, Lyndon B Johnson Space Ctr, Human Adaptat & Countermeasures Off, Space & Life Sci Directorate, Houston, TX 77058 USA. RP Berkowitz, DE (reprint author), Johns Hopkins Univ Hosp, 600 N Wolfe St, Baltimore, MD 21287 USA. EM dberkowi@bme.jhu.edu FU NCI NIH HHS [CA-00405]; NIA NIH HHS [R01-AG-021523] NR 30 TC 29 Z9 30 U1 1 U2 5 PU AMER PHYSIOLOGICAL SOC PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814 USA SN 8750-7587 J9 J APPL PHYSIOL JI J. Appl. Physiol. PD MAR PY 2007 VL 102 IS 3 BP 853 EP 858 DI 10.1152/japplphysiol.00950.2006 PG 6 WC Physiology; Sport Sciences SC Physiology; Sport Sciences GA 143LF UT WOS:000244722400007 PM 17082368 ER PT J AU Mattioli, V Westwater, ER Cimini, D Liljegren, JC Lesht, BM Gutman, SI Schmidlin, FJ AF Mattioli, V. Westwater, E. R. Cimini, D. Liljegren, J. C. Lesht, B. M. Gutman, S. I. Schmidlin, F. J. TI Analysis of radiosonde and ground-based remotely sensed PWV data from the 2004 North Slope of Alaska Arctic Winter Radiometric Experiment SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article ID INTENSIVE OBSERVATION PERIODS; CHILLED-MIRROR HYGROMETER; GLOBAL POSITIONING SYSTEM; WATER-VAPOR MEASUREMENTS; MICROWAVE RADIOMETERS; PRECIPITABLE WATER; GPS METEOROLOGY; TEMPERATURE; PERFORMANCE; TROPOSPHERE AB During 9 March-9 April 2004, the North Slope of Alaska Arctic Winter Radiometric Experiment was conducted at the Atmospheric Radiation Measurement Program's ( ARM) "Great White" field site near Barrow, Alaska. The major goals of the experiment were to compare microwave and millimeter wavelength radiometers and to develop forward models in radiative transfer, all with a focus on cold ( temperature from 0 degrees to - 40 degrees C) and dry [ precipitable water vapor ( PWV) < 0.5 cm] conditions. To supplement the remote sensors, several radiosonde packages were deployed: Vaisala RS90 launched at the ARM Duplex and at the Great White and Sippican VIZ-B2 operated by the NWS. In addition, eight dual-radiosonde launches were conducted at the Duplex with Vaisala RS90 and Sippican GPS Mark II, the latter one modified to include a chilled mirror humidity sensor. Temperature comparisons showed a nighttime bias between VIZ-B2 and RS90, which reached 3.5 degrees C at 30 hPa. Relative humidity comparisons indicated better than 5% average agreement between the RS90 and the chilled mirror. A bias of about 20% for the upper troposphere was found in the VIZ-B2 and the Mark II measurements relative to both RS90 and the chilled mirror. Comparisons in PWV were made between a microwave radiometer, a microwave profiler, a global positioning system receiver, and the radiosonde types. An RMS agreement of 0.033 cm was found between the radiometer and the profiler and better than 0.058 cm between the radiometers and GPS. RS90 showed a daytime dry bias on PWV of about 0.02 cm. C1 Univ Perugia, DIEI, I-06125 Perugia, Italy. Sci & Technol Corp, Hampton, VA USA. Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. NOAA, ESRL Phys Sci Div, Boulder, CO 80309 USA. CNR, Inst Methodol Environm Anal, Tito, Italy. Argonne Natl Lab, DOE, Argonne, IL 60439 USA. NOAA, Forecast Syst Lab, Boulder, CO 80303 USA. NASA, Goddard Space Flight Ctr, Wallops Flight Facil, Wallops Isl, VA 23337 USA. RP Mattioli, V (reprint author), Univ Perugia, DIEI, Via G Duranti 93, I-06125 Perugia, Italy. EM vinia.mattioli@diei.unipg.it RI Cimini, Domenico/M-8707-2013; OI Cimini, Domenico/0000-0002-5962-223X; Lesht, Barry/0000-0003-0801-4290 NR 39 TC 38 Z9 38 U1 0 U2 3 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0739-0572 J9 J ATMOS OCEAN TECH JI J. Atmos. Ocean. Technol. PD MAR PY 2007 VL 24 IS 3 BP 415 EP 431 DI 10.1175/JTECH1982.1 PG 17 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA 150MX UT WOS:000245222000008 ER PT J AU Ji, Q AF Ji, Qiang TI A method to correct the thermal dome effect of pyranometers in selected historical solar irradiance measurements SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article ID CALIBRATION; SURFACE AB In using pyranometers to measure solar irradiance, it is important to know the magnitudes and the consequences of the thermal effect, which is introduced by the glass domes of the instruments. Historically, the thermal dome effect was not monitored on a regular basis. Case studies show that, due to the thermal dome effect, the output of the pyranometers altered from less than 5 W m(-2) in the nighttime to over 20 W m(-2) around noontime during the Aerosol Recirculation and Rainfall Experiment ( ARREX) in 1999 and the Southern African Fire - Atmosphere Research Initiative ( SAFARI) in 2000 field campaigns, depending on sky conditions. A calibration and data processing procedure with the thermal dome effect incorporated has been tested to resolve the issue. It is demonstrated that the intrinsic calibration constants of the pyranometers can be obtained if two pyranometers are used side by side, and the thermal dome effect may be inferred whenever a pyranometer and a pyrgeometer are collocated. C1 Univ Maryland, Earth Syst Sci Interdisciplinary Ctr, College Pk, MD 20742 USA. RP Ji, Q (reprint author), NASA, Goddard Space Flight Ctr, Code 613-2, Greenbelt, MD 20771 USA. EM ji@climate.gsfc.nasa.gov NR 12 TC 7 Z9 7 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0739-0572 J9 J ATMOS OCEAN TECH JI J. Atmos. Ocean. Technol. PD MAR PY 2007 VL 24 IS 3 BP 529 EP 536 DI 10.1175/JTECH1977.1 PG 8 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA 150MX UT WOS:000245222000016 ER PT J AU Ostgaard, N Mende, SB Frey, HU Sigwarth, JB Asnes, A Weygand, JM AF Ostgaard, N. Mende, S. B. Frey, H. U. Sigwarth, J. B. Asnes, A. Weygand, J. M. TI Auroral conjugacy studies based on global imaging SO JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS LA English DT Article; Proceedings Paper CT Yosemite Workshop on Global Aspects of Magnetosphere-Ionosphere Coupling CY FEB 07-10, 2006 CL Yosemite Natl Park, Yosemite, CA HO Yosemite Natl Park DE conjugate imaging; cusp aurora; theta aurora; substorm location; magnetospheric configuration; IMF control ID INTERPLANETARY MAGNETIC-FIELD; SUBSTORM ONSET; POLAR SPACECRAFT; NORTHWARD IMF; HEMISPHERES; LOCATION; ARCS; MAGNETOSPHERE; RECONNECTION; MAGNETOPAUSE AB Simultaneous global imaging in the ultraviolet wavelengths by IMAGE and Polar, enable us to examine auroral features in the conjugate hemispheres. With an imaging cadence of 2 and 1 min for IMAGE-FUV and Polar VIS Earth camera, respectively, we have examined dynamic features such as substorm onsets and cusp precipitation as well as slowly varying phenomena such as theta aurora. In this paper, we review the main findings from these studies and present new evidence of the IMF clock angle control of the asymmetric substorm onset locations. Simultaneous images from the opposite hemispheres show asymmetric cusp auroras and their locations are controlled by IMF B-y and dipole tilt angle. Our imaging results demonstrate. that theta aurora can be a non-conjugate phenomenon. We suggest that IMF B-x controls in which hemisphere the theta aurora occurs. For substorm onset locations, we have found that there exists a systematic displacement in one hemisphere compared to the other. The relative displacement of onset locations in the conjugate hemispheres is found to be controlled primarily by the IMF clock angle. Compared with some of the existing magnetic field models, the observed asymmetries are an order of magnitude larger than the model predictions. Statistical distribution of substorm onset locations in the southern and northern hemispheres for different clock angles enables us to validate the IMF clock angle control. Based on similar to 3000 substorm onsets in the northern hemisphere and similar to 1000 in the southern hemisphere observed by IMAGE we find a remarkable support for our previous findings. (c) 2006 Elsevier Ltd. All rights reserved. C1 Univ Bergen, Dept Phys & Technol, N-5007 Bergen, Norway. Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. NASA, Goddard Space Flight Ctr, Lab Extratterrestrial Phys, Electrodynam Branch, Greenbelt, MD 20771 USA. Los Alamos Natl Lab, Los Alamos, NM USA. Univ Calif Los Angeles, Inst Geophys & Planetary Phys, Los Angeles, CA 90024 USA. RP Ostgaard, N (reprint author), Univ Bergen, Dept Phys & Technol, Allegt 55, N-5007 Bergen, Norway. EM Nikolai.Ostgaard@ift.uib.no OI Frey, Harald/0000-0001-8955-3282 NR 34 TC 29 Z9 29 U1 0 U2 7 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1364-6826 J9 J ATMOS SOL-TERR PHY JI J. Atmos. Sol.-Terr. Phys. PD MAR PY 2007 VL 69 IS 3 SI SI BP 249 EP 255 DI 10.1016/j.jastp.2006.05.026 PG 7 WC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences SC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences GA 158EK UT WOS:000245773900006 ER PT J AU Moore, TE Fok, MC Delcourt, DC Slinker, SP Fedder, JA AF Moore, T. E. Fok, M.-C. Delcourt, D. C. Slinker, S. P. Fedder, J. A. TI Global aspects of solar wind-ionosphere interactions SO JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS LA English DT Article; Proceedings Paper CT Yosemite Workshop on Global Aspects of Magnetosphere-Ionosphere Coupling CY FEB 07-10, 2006 CL Yosemite Natl Park, Yosemite, CA HO Yosemite Natl Park DE solar wind; ionosphere; plasma; heating; circulation ID HIGH-LATITUDE IONOSPHERE; PLASMA SHEET; RING CURRENT; ION OUTFLOW; POLAR AB Recent observations have quantified the auroral wind O(+) outflow in response to magnetospheric inputs to the ionosphere, notably Poynting energy flux and precipitating electron density. For moderate to high activity periods, ionospheric O(+) is observed to become a significant or dominant component of plasma pressure in the inner plasma sheet and ring current regions. Using a global circulation model of magnetospheric fields and its imposed ionospheric boundary conditions, we evaluate the, global ionospheric plasma response to local magnetospheric conditions imposed by the simulation and evaluate magnetospheric circulation of solar wind H(+), polar wind H(+), and amoral wind O(+). We launch and track the motions of millions of test particles in the global fields, launched at randomly distributed positions and times. Each particle is launched with a flux weighting and perpendicular and parallel energies randomly selected from defined thermal ranges appropriate to the launch point. One sequence is driven by a two-hour period of southward interplanetary magnetic field for average solar wind intensity. A second is driven by a 2-h period of enhanced solar wind dynamic pressure for average interplanetary field. We find that the simulated ionospheric O(+) becomes a significant plasma pressure component in the inner plasma sheet and outer ring current region, particularly when the solar wind is intense or its magnetic field is southward directed. We infer that the reported empirical scalings of auroral wind O(+) outflows are consistent with a substantial pressure contribution to the inner plasma sheet and plasma source surrounding the ring current. This result violates the common assumption that the ionospheric load is entirely confined to the F layer, and shows that the ionosphere is often an important dynamic element throughout the magnetosphere during moderate to large solar wind disturbances. (c) 2006 Elsevier Ltd. All rights reserved. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. CETP, F-94107 St Maur des Fosses, France. USN, Res Lab, Washington, DC 20375 USA. LET Corp, Washington, DC USA. RP Moore, TE (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. EM thomas.e.moore@nsaa.gov RI Moore, Thomas/D-4675-2012; Fok, Mei-Ching/D-1626-2012 OI Moore, Thomas/0000-0002-3150-1137; NR 24 TC 24 Z9 24 U1 0 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1364-6826 J9 J ATMOS SOL-TERR PHY JI J. Atmos. Sol.-Terr. Phys. PD MAR PY 2007 VL 69 IS 3 SI SI BP 265 EP 278 DI 10.1016/j.jastp.2006.08.009 PG 14 WC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences SC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences GA 158EK UT WOS:000245773900008 ER PT J AU Gallagher, DL Adrian, ML AF Gallagher, D. L. Adrian, Mark L. TI Two-dimensional drift velocities from the IMAGE EUV plasmaspheric imager SO JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS LA English DT Article; Proceedings Paper CT Yosemite Workshop on Global Aspects of Magnetosphere-Ionosphere Coupling CY FEB 07-10, 2006 CL Yosemite Natl Park, Yosemite, CA HO Yosemite Natl Park DE plasmasphere; convection; electric fields; plasmaspheric erosion ID INNER MAGNETOSPHERE; ART.; PLASMAPAUSE; DYNAMICS; SPACECRAFT; MISSION; REGION AB The Imager for Magnetopause-to-Aurora Global Exploration (IMAGE) Mission extreme ultraviolet (EUV) imager observes He+ plasmaspheric ions throughout the inner magnetosphere. Limited by ionizing radiation and viewing close to the sun, images of the He+ distribution are available every 10 min for many hours as the spacecraft passes through apogee in its highly elliptical orbit. As a consistent constituent at about 15%, He+ is an excellent surrogate for monitoring all of the processes that control the dynamics of plasmaspheric plasma. In particular, the motion of He+ transverse to the ambient magnetic field is a direct indication of convective electric fields. The analysis of boundary motions has already achieved new insights into the electrodynamic coupling processes taking place between energetic magnetospheric plasmas and the ionosphere. Yet to be fulfilled, however, is the original promise that global EUV images of the plasmasphere might yield two-dimensional pictures of mesoscale to macroscale electric fields in the inner magnetosphere. This work details the technique and initial application of an IMAGE EUV analysis that appears capable of following thermal plasma motion on a global basis. (c) 2006 Elsevier Ltd. All rights reserved. C1 NASA, George C Marshall Space Flight Ctr, Natl Space Sci & Technol Ctr, Huntsville, AL 35805 USA. NASA, Goddard Space Flight Ctr, Heliospher Phys Branch, Greenbelt, MD 20771 USA. RP Gallagher, DL (reprint author), NASA, George C Marshall Space Flight Ctr, Natl Space Sci & Technol Ctr, Mail Code VP62,320 Sparkman Dr, Huntsville, AL 35805 USA. EM dennis.l.gallagher@nasa.gov NR 29 TC 9 Z9 9 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1364-6826 J9 J ATMOS SOL-TERR PHY JI J. Atmos. Sol.-Terr. Phys. PD MAR PY 2007 VL 69 IS 3 SI SI BP 341 EP 350 DI 10.1016/j.jastp.2006.05.028 PG 10 WC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences SC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences GA 158EK UT WOS:000245773900015 ER PT J AU Tie, X Chandra, S Ziemke, JR Granier, C Brasseur, GP AF Tie, X. Chandra, S. Ziemke, J. R. Granier, C. Brasseur, G. P. TI Satellite measurements of tropospheric column O(3) and NO(2) in eastern and southeastern Asia: Comparison with a global model (MOZART-2) SO JOURNAL OF ATMOSPHERIC CHEMISTRY LA English DT Article DE ozone and NO(2) in Asia; TOMS/MLS; GOME; MOZART-2 ID 1997-1998 EL-NINO; GOME MEASUREMENTS; UNITED-STATES; OZONE CHANGES; NITROGEN; SENSITIVITY; SIMULATION; ATMOSPHERE; CHEMISTRY; EMISSIONS AB Satellite measurements of tropospheric column O(3) and NO(2) in eastern and southeastern Asia are analyzed to study the spatial and seasonal characteristics of pollution in these regions. Tropospheric column O(3) is derived from differential measurements of total column ozone from Total Ozone Mapping Spectrometer (TOMS), and stratospheric column ozone from the Microwave Limb Sounder (MLS) instrument on the Upper Atmosphere Research Satellite (UARS). The tropospheric column NO(2) is measured by Global Ozone Monitoring Experiment (GOME). A global chemical and transport model (Model of Ozone and Related Chemical Tracers, version 2; MOZART-2) is applied to analyze and interpret the satellite measurements. The study, which is based on spring, summer, and fall months of 1997 shows generally good agreement between the model and satellite data with respect to seasonal and spatial characteristics of O(3) and NO(2) fields. The analysis of the model results show that the industrial emission of NO(x) (NO+NO(2)) contributes about 50%-80% to tropospheric column NO(2) in eastern Asia and about 20%-50% in southeastern Asia. The contribution of industrial emission of NO(x) to tropospheric column O(3) ranges from 10% to 30% in eastern Asia. Biomass burning and lightning NO(x) emissions have a small effect on tropospheric O(3) in central and eastern Asia, but they have a significant impact in southeastern Asia. The varying effects of NO(x) on tropospheric column ozone are attributed to differences in relative abundance of volatile organic compounds (VOCs) with respect to total nitrogen in the two regions. C1 Natl Ctr Atmospher Res, Boulder, CO 80307 USA. Univ Maryland Baltimore Cty, Goddard Earth Sci & Technol, Baltimore, MD 21228 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NOAA, Boulder, CO USA. Max Planck Inst Meteorol, Hamburg, Germany. RP Tie, X (reprint author), Natl Ctr Atmospher Res, POB 3000, Boulder, CO 80307 USA. EM xxtie@ucar.edu RI Granier, Claire/D-5360-2013 OI Granier, Claire/0000-0001-7344-7995 NR 32 TC 7 Z9 9 U1 1 U2 5 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0167-7764 J9 J ATMOS CHEM JI J. Atmos. Chem. PD MAR PY 2007 VL 56 IS 2 BP 105 EP 125 DI 10.1007/s10874-006-9045-7 PG 21 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA 135XN UT WOS:000244187300001 ER PT J AU Xu, KM Wong, T Wielicki, BA Parker, L Lin, B Eitzen, ZA Branson, M AF Xu, Kuan-Man Wong, Takmeng Wielicki, Bruce A. Parker, Lindsay Lin, Bing Eitzen, Zachary A. Branson, Mark TI Statistical analyses of satellite cloud object data from CERES. Part II: Tropical convective cloud objects during 1998 El Nino and evidence for supporting the fixed anvil temperature hypothesis SO JOURNAL OF CLIMATE LA English DT Article ID SEA-SURFACE TEMPERATURE; LARGE-SCALE CIRCULATION; WATER-VAPOR; INFRARED IRIS; CIRRUS; CLIMATE; RADIATION; EARTH; SENSITIVITY; FEEDBACK AB Characteristics of tropical deep convective cloud objects observed over the tropical Pacific during January-August 1998 are examined using the Tropical Rainfall Measuring Mission/Clouds and the Earth's Radiant Energy System Single Scanner Footprint (SSF) data. These characteristics include the frequencies of occurrence and statistical distributions of cloud physical properties. Their variations with cloud object size, sea surface temperature (SST), and satellite precession cycle are analyzed in detail. A cloud object is defined as a contiguous patch of the earth composed of satellite footprints within a single dominant cloud-system type. It is found that statistical distributions of cloud physical properties are significantly different among three size categories of cloud objects with equivalent diameters of 100-150 (small), 150-300 (medium), and > 300 km (large), except for the distributions of ice particle size. The distributions for the larger-size category of cloud objects are more skewed toward high SSTs, high cloud tops, low cloud-top temperature, large ice water path, high cloud optical depth, low outgoing longwave (LW) radiation, and high albedo than the smaller-size category. As SST varied from one satellite precession cycle to another, the changes in macrophysical properties of cloud objects over the entire tropical Pacific were small for the large-size category of cloud objects, relative to those of the small- and medium-size categories. This evidence supports the fixed anvil temperature hypothesis of Hartmann and Larson for the large-size category. Combined with the result that a higher percentage of the large-size category of cloud objects occurs during higher SST subperiods, this implies that macro-physical properties of cloud objects would be less sensitive to further warming of the climate. On the other hand, when cloud objects are classified according to SST ranges, statistical characteristics of cloud microphysical properties, optical depth, and albedo are not sensitive to the SST, but those of cloud macrophysical properties are dependent upon the SST. This result is related to larger differences in large-scale dynamics among the SST ranges than among the satellite precession cycles. Frequency distributions of vertical velocity from the European Centre for Medium-Range Weather Forecasts model that is matched to each cloud object are used to further understand some of the findings in this study. C1 NASA, Langley Res Ctr, Climate Sci Branch, Hampton, VA 23681 USA. Sci Applicat Int Corp, Hampton, VA USA. Colorado State Univ, Ft Collins, CO 80523 USA. RP Xu, KM (reprint author), NASA, Langley Res Ctr, Climate Sci Branch, Mail Stop 420, Hampton, VA 23681 USA. EM Kuan-Man.Xu@nasa.gov RI Xu, Kuan-Man/B-7557-2013 OI Xu, Kuan-Man/0000-0001-7851-2629 NR 35 TC 25 Z9 25 U1 0 U2 5 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8755 J9 J CLIMATE JI J. Clim. PD MAR 1 PY 2007 VL 20 IS 5 BP 819 EP 842 DI 10.1175/JCLI4069.1 PG 24 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 143IM UT WOS:000244714000004 ER PT J AU Kang, HS Xue, YK Collatz, GJ AF Kang, Hyun-Suk Xue, Yongkang Collatz, G. James TI Impact assessment of satellite-derived leaf area index datasets using a general circulation model SO JOURNAL OF CLIMATE LA English DT Article ID LAND-SURFACE PROCESSES; TROPICAL NORTH-AFRICA; MONSOON DEVELOPMENT; WEATHER PREDICTION; VEGETATION INDEX; BIOSPHERE MODEL; ABSORBED PAR; ANNUAL CYCLE; CLIMATE; PRECIPITATION AB This study assesses the impact of two different remote sensing -derived leaf area index (RSLAI) datasets retrieved from the same source (i.e., Advanced Very High Resolution Radiometer measurements) on a general circulation model's (GCM) seasonal climate simulations as well as the mechanisms that lead to the improvement in simulations over several regions. Based on the analysis of these two RSLAI datasets for 17 yr from 1982 to 1998, their spatial distribution patterns and characteristics are discussed. Despite some disagreements in the RSLAI magnitudes and the temporal variability between these two datasets over some areas, their effects on the simulation of near-surface climate and the regions with significant impact are generally similar to each other. Major disagreements in the simulated climate appear in a few limited regions. The GCM experiment using the RSLAI and other satellite-derived land surface products showed substantial improvements in the near-surface climate in the East Asian and West African summer monsoon areas and boreal forests of North America compared to the control experiment that used LAI extrapolated from limited ground surveys. For the East Asia and northwest U. S. regions, the major role of RSLAI changes is in partitioning the net radiative energy into latent and sensible heat fluxes, which results in discernable warming and decrease of precipitation due to the smaller RSLAI values compared to the control. Meanwhile, for the West African semiarid regions, where the LAI difference between RSLAI and control experiments is negligible, the decrease in surface albedo caused by the high vegetation cover fraction in the satellite-derived dataset plays an important role in altering local circulation that produces a positive feedback in land/atmosphere interaction. C1 Univ Calif Los Angeles, Dept Geog, Los Angeles, CA 90095 USA. Univ Calif Los Angeles, Dept Atmospher & Ocean Sci, Los Angeles, CA 90095 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Xue, YK (reprint author), Univ Calif Los Angeles, Dept Geog, 1255 Bunche Hall,POB 951524, Los Angeles, CA 90095 USA. EM yxue@geog.ucla.edu RI collatz, george/D-5381-2012 NR 43 TC 16 Z9 19 U1 1 U2 14 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8755 J9 J CLIMATE JI J. Clim. PD MAR PY 2007 VL 20 IS 6 BP 993 EP 1015 DI 10.1175/JCLI4054.1 PG 23 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 150JG UT WOS:000245211700004 ER PT J AU Dewitte, B Cibot, C Perigaud, C An, SI Terray, L AF Dewitte, Boris Cibot, Carole Perigaud, Claire An, Soon-Il Terray, Laurent TI Interaction between near-annual and ENSO modes in a CGCM simulation: Role of the equatorial background mean state SO JOURNAL OF CLIMATE LA English DT Article ID NINO SOUTHERN-OSCILLATION; EL-NINO; PACIFIC-OCEAN; DECADAL VARIABILITY; TROPICAL PACIFIC; COUPLED MODEL; INTERDECADAL CHANGES; CIRCULATION; ASYMMETRY; FREQUENCY AB A 260-yr-long coupled general circulation model (CGCM) simulation is used to investigate the interaction between ENSO mode and near-annual variability and its sensitivity to the equatorial background mean stratification and seasonal cycles. Although the thermocline mean vertical structure of the model favors the high-order baroclinic modes that are associated with the slow time scales of the coupled variability, the simulated ENSO oscillates at a dominant quasi-biennial frequency. Biases of the climatological velocity field are favorable to the dominance of the zonal advective feedback over the thermocline feedback, the model exhibiting an overenergetic westward seasonal zonal current in the central-western equatorial Pacific, and an upwelling rate that is about half the observations. This sets the conditions for the enhancement of a near-annual mode that is observed to oscillate at an 8-month period in the model. Using an intermediate coupled model of the tropical Pacific where the climatological fields are prescribed to the ones derived from the CGCM, it is demonstrated that the quasi-biennial ENSO variability simulated by the CGCM is mostly due to the biases in the climatological currents of the CGCM. These biases favor the dominance of the fast "zonal advective feedback" over the slow "thermocline feedback" in the coupled system and enhance a fast coupled basin mode. This fast mode differs from the theoretical Pacific Ocean basin mode in that, besides mean temperature advection by the zonal current anomalies, it is also driven by anomalous temperature advection by the total current. Results suggest that the near-annual mode destabilizes the ENSO mode to produce overenergetic quasi-biennial oscillations in the model. It also contributes to the ENSO asymmetry and the cold bias of the CGCM mean state by nonlinear accumulation of temperature zonal advection, which works toward the cold in the western Pacific more than the warm in the east. It is suggested that the model equilibrium results from the interaction between the ENSO mode, the near-annual mode, and the mean state. C1 LEGOS, F-31401 Toulouse 4, France. CNRS, CERFACS, Climate Change & Climate Modeling Team, Toulouse, France. CALTECH, Jet Prop Lab, Pasadena, CA USA. Univ Hawaii Manoa, IPRC, Honolulu, HI 96822 USA. RP Dewitte, B (reprint author), LEGOS, 14 Av Edouard Belin, F-31401 Toulouse 4, France. EM boris.dewitte@cnes.fr RI AN, SOON-IL/E-5721-2013; Terray, Laurent/B-8056-2008 OI Terray, Laurent/0000-0001-5512-7074 NR 40 TC 19 Z9 19 U1 0 U2 2 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8755 EI 1520-0442 J9 J CLIMATE JI J. Clim. PD MAR PY 2007 VL 20 IS 6 BP 1035 EP 1052 DI 10.1175/JCLI4060.1 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 150JG UT WOS:000245211700006 ER PT J AU Maimone, M Cheng, Y Matthies, L AF Maimone, Mark Cheng, Yang Matthies, Larry TI Two years of Visual Odometry on the Mars Exploration Rovers SO JOURNAL OF FIELD ROBOTICS LA English DT Article ID MOBILE ROBOT; NAVIGATION; MOTION; LOCALIZATION AB NASA's two Mars Exploration Rovers (MER) have successfully demonstrated a robotic Visual Odometry capability on another world for the first time. This provides each rover with accurate knowledge of its position, allowing it to autonomously detect and compensate for any unforeseen slip encountered during a drive. It has enabled the rovers to drive safely and more effectively in highly sloped and sandy terrains and has resulted in increased mission science return by reducing the number of days required to drive into interesting areas. The MER Visual Odometry system comprises onboard software for comparing stereo pairs taken by the pointable mast-mounted 45 deg FOV Navigation cameras (NAVCAMs). The system computes an update to the 6 degree of freedom rover pose (x, y, z, roll, pitch, yaw) by tracking the motion of autonomously selected terrain features between two pairs of 256 X 256 stereo images. It has demonstrated good performance with high rates of successful convergence (97% on Spirit, 95% on Opportunity), successfully detected slip ratios as high as 125%, and measured changes as small as 2 mm, even while driving on slopes as high as 31 deg. Visual Odometry Was used over 14%, of the first 10.7 km driven by both rovers. During the first 2 years of operations, Visual Odometry evolved from an "extra credit" capability into a critical vehicle safety system. In this paper we describe our Visual Odometry algorithm, discuss several driving strategies that rely on it (including Slip Checks, Keep-out Zones, and Wheel Dragging), and summarize its results from the first 2 years of operations on Mars. (c) 2007 Wiley Periodicals, Inc. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Maimone, M (reprint author), CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. EM mark.maimone@jpl.nasa.gov NR 29 TC 205 Z9 224 U1 3 U2 24 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 1556-4959 J9 J FIELD ROBOT JI J. Field Robot. PD MAR PY 2007 VL 24 IS 3 BP 169 EP 186 DI 10.1002/rob.20184 PG 18 WC Robotics SC Robotics GA 162KS UT WOS:000246086700002 ER PT J AU Li, RX Di, KC Howard, AB Matthies, L Wang, J Agarwal, S AF Li, Rongxing Di, Kaichang Howard, Andrew B. Matthies, Larry Wang, Jue Agarwal, Sanchit TI Rock modeling and matching for autonomous long-range Mars rover localization SO JOURNAL OF FIELD ROBOTICS LA English DT Article ID EXPLORATION; NAVIGATION; MISSION AB This paper introduces the concept and design of a new integrated approach to long-range autonomous Mars rover localization based on the incremental bundle adjustment and visual odometry technologies that have been individually experimented with during the 2003 Mars Exploration Rover mission. The design result indicates that a rover would have a varying performance in traversing from 7.5 to 118 m within one traverse leg under various scenarios including camera systems and traverse geometry, while maintaining the onboard rover localization accuracy at 1%. To implement the proposed integrated approach, the key is to develop autonomous cross-site tie point selection algorithms for automatic generation of a sufficient number of high quality tie points to link all the images and to form the image network. New methods of rock extraction, rock modeling, and rock matching from multiple rover sites are developed to automate cross-site tie point selection. Rocks are extracted from three-dimensional ground points generated by stereo image matching, and then modeled using analytical surfaces such as hemispheroid, semiellipsoid, cone, and tetrahedron. Rocks extracted and modeled from two rover sites are matched by a combination of rock model matching and rock distribution pattern matching. The matched rocks are used as cross-site tie points for a subsequent bundle adjustment. The presented results show that the proposed cross-site tie point selection approach functions successfully for medium-range (up to 26 m) traverse legs. (c) 2007 Wiley Periodicals, Inc. C1 Ohio State Univ, Mapping & GIS Lab, CEEGS, Columbus, OH 43210 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Li, RX (reprint author), Ohio State Univ, Mapping & GIS Lab, CEEGS, Columbus, OH 43210 USA. EM li.282@osu.edu; di.2@osu.edu; abhoward@robotics.jpl.nasa.gov; lhm@robotics.jpl.nasa.gov; wang.813@osu.edu; agarwal.59@osu.edu RI Wang, Jue/C-9215-2009; OI Wang, Jue/0000-0002-9901-9996; di, kai chang/0000-0001-6581-6615 NR 36 TC 19 Z9 21 U1 0 U2 1 PU JOHN WILEY & SONS INC PI HOBOKEN PA 111 RIVER ST, HOBOKEN, NJ 07030 USA SN 1556-4959 J9 J FIELD ROBOT JI J. Field Robot. PD MAR PY 2007 VL 24 IS 3 BP 187 EP 203 DI 10.1002/rob.20182 PG 17 WC Robotics SC Robotics GA 162KS UT WOS:000246086700003 ER PT J AU Angelova, A Matthies, L Helmick, D Perona, P AF Angelova, Anelia Matthies, Larry Helmick, Daniel Perona, Pietro TI Learning and prediction of slip from visual information SO JOURNAL OF FIELD ROBOTICS LA English DT Article ID ROUGH TERRAIN; ROVER; NAVIGATION AB This paper presents an approach for slip prediction from a distance for wheeled ground robots using visual information as input. Large amounts of slippage which can occur on certain surfaces, such as sandy slopes, will negatively affect rover mobility. Therefore, obtaining information about slip before entering such terrain can be very useful for better planning and avoiding these areas. To address this problem, terrain appearance and geometry information about map cells are correlated to the slip measured by the rover while traversing each cell. This relationship is learned from previous experience, so slip can be predicted remotely from visual information only. The proposed method consists of terrain type recognition and nonlinear regression modeling. The method has been implemented and tested offline on several off-road terrains including: soil, sand, gravel, and woodchips. The final slip prediction error is about 20%. The system is intended for improved navigation on steep slopes and rough terrain for Mars rovers. (c) 2007 Wiley Periodicals, Inc. C1 CALTECH, Dept Comp Sci, Pasadena, CA 91125 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. CALTECH, Dept Elect Engn, Pasadena, CA 91125 USA. RP Angelova, A (reprint author), CALTECH, Dept Comp Sci, Pasadena, CA 91125 USA. EM anelia@caltech.edu; lhm@jpl.nasa.gov; dhelmick@jpl.nasa.gov; perona@caltech.edu NR 62 TC 46 Z9 48 U1 1 U2 3 PU WILEY-BLACKWELL PI HOBOKEN PA 111 RIVER ST, HOBOKEN 07030-5774, NJ USA SN 1556-4959 EI 1556-4967 J9 J FIELD ROBOT JI J. Field Robot. PD MAR PY 2007 VL 24 IS 3 BP 205 EP 231 DI 10.1002/rob.20179 PG 27 WC Robotics SC Robotics GA 162KS UT WOS:000246086700004 ER PT J AU Rahmani, RK Ayasoufi, A AF Rahmani, Ramin K. Ayasoufi, Anahita TI A numerical study of the global performance of two static mixers SO JOURNAL OF FLUIDS ENGINEERING-TRANSACTIONS OF THE ASME LA English DT Article; Proceedings Paper CT ASME International Mechanical Engineering Congress and Exposition CY NOV 05-11, 2005 CL Orlando, FL SP ASME, Proc Ind Div, ASME, Rail Transportat Div, ASME, Noise Control & Acoust Div, ASME, Triol Div, ASME, Pressure Vessels & Piping Div, ASME, Bioengn Div, ASME, Mat Div, ASME, Appl Mech Div, ASME, Fluids Engn Div, ASME, Micro Elect Mech Syst Div, ASME, Heat Transfer Div, ASME, Nucl Engn Div, ASME, Power Div, ASME, Solar Energy Div, ASME, Safety Engn & Risk Anal Div, ASME, Technol & Soc Div, ASME, Adv Energy Syst Div, ASME, Aerosp Div, ASME, Comp & Informat Engn Div DE helical static mixer; SMX static mixer; particles distribution uniformity; residence time distribution; shear-thinning fluids; shear-thickening fluids ID HEAT-TRANSFER; PRESSURE-DROP; RESIDENCE TIME; LAMINAR-FLOW; FLUIDS; SIMULATION AB The use of in-line static mixers has been widely advocated for an important variety of applications, such as continuous mixing, heat and mass transfer processes, and chemical reactions. This paper extends previous studies by the authors on industrial static mixers and illustrates how static mixing processes of single-phase viscous liquids can be numerically simulated. Mixing of Newtonian, shear-thinning, and shear-thickening fluids through static mixer, as well as thermal enhancement by static mixer is studied. Using different measuring tools, the global performance and costs of SMX (Sulzer mixer X) and helical static mixers are studied. It is shown that the SMX mixer manifests a higher performance; however the required energy to maintain the flow across a SMX mixer is significantly higher. C1 Univ Alabama, Dept Mech Engn, Birmingham, AL 35294 USA. NASA, Glenn Res Ctr, Director Res & Technol Directorate, Cleveland, OH USA. RP Rahmani, RK (reprint author), Univ Alabama, Dept Mech Engn, Birmingham, AL 35294 USA. EM rkhrahmani@yahoo.com; aayasoufi@yahoo.com NR 47 TC 3 Z9 3 U1 0 U2 12 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA THREE PARK AVE, NEW YORK, NY 10016-5990 USA SN 0098-2202 J9 J FLUID ENG-T ASME JI J. Fluids Eng.-Trans. ASME PD MAR PY 2007 VL 129 IS 3 BP 338 EP 349 DI 10.1115/1.2427082 PG 12 WC Engineering, Mechanical SC Engineering GA 151OV UT WOS:000245300900011 ER PT J AU Kahn, BH Eldering, A Braverman, AJ Fetzer, EJ Jiang, JH Fishbein, E Wu, DL AF Kahn, Brian H. Eldering, Annmarie Braverman, Amy J. Fetzer, Eric J. Jiang, Jonathan H. Fishbein, Evan Wu, Dong L. TI Toward the characterization of upper tropospheric clouds using Atmospheric Infrared Sounder and Microwave Limb Sounder observations SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID CIRRUS CLOUDS; TOP HEIGHTS; NAURU ISLAND; WATER-VAPOR; ARM SITE; SAGE-II; EOS MLS; ART.; SATELLITE; LIDAR AB We estimate the accuracy of cloud top altitude (Z) retrievals from the Atmospheric Infrared Sounder ( AIRS) and Advanced Microwave Sounding Unit (AMSU) observing suite (ZA) on board the Earth Observing System Aqua platform. We compare Z(A) with coincident measurements of Z derived from the micropulse lidar and millimeter wave cloud radar at the Atmospheric Radiation Measurement (ARM) program sites of Nauru and Manus islands (Z(ARM)) and the inferred Z from vertically resolved Microwave Limb Sounder (MLS) ice water content (IWC) retrievals. The mean difference in ZA minus ZARM plus or minus one standard deviation ranges from -2.2 to 1.6 km +/- 1.0 to 4.2 km for all cases of AIRS effective cloud fraction (f(A)) > 0.15 at Manus Island using the cloud radar only. The range of mean values results from using different approaches to determine Z(ARM), day/night differences, and the magnitude of f(A); the variation about the mean decreases for increasing values of f(A). Analysis of ZARM from the micropulse lidar at Nauru Island for cases restricted to 0.05 <= f(A) <= 0.15 indicates a statistically significant improvement in Z(A) - Z(ARM) over the cloud radar-derived values at Manus Island. In these cases the Z(A)-Z(ARM) difference is -1.1 to 2.1 km +/- 3.0 to 4.5 km. These results imply that the operational Z(A) is quantitatively useful for constraining cirrus altitude despite the nominal 45 km horizontal resolution. Mean differences of cloud top pressure (P-CLD) inferred from coincident AIRS and MLS ice water content ( IWC) retrievals depend upon the method of defining AIRS P-CLD ( as with the ARM comparisons) over the MLS spatial scale, the peak altitude and maximum value of MLS IWC, and fA. AIRS and MLS yield similar vertical frequency distributions when comparisons are limited to f(A) > 0.1 and IWC > 1.0 mg m(-3). Therefore the agreement depends upon the opacity of the cloud, with decreased agreement for optically tenuous clouds. Further, the mean difference and standard deviation of AIRS and MLS PCLD are highly dependent on the MLS tangent altitude. For MLS tangent altitudes greater than 146 hPa, the strength of the limb technique, the disagreement becomes statistically significant. This implies that AIRS and MLS "agree'' in a statistical sense at lower tangent altitudes and "disagree'' at higher tangent altitudes. These results provide important insights on upper tropospheric cloudiness as observed by nadir-viewing AIRS and limb-viewing MLS. C1 Jet Propuls Lab, Pasadena, CA USA. RP Kahn, BH (reprint author), Jet Propuls Lab, Pasadena, CA USA. EM brian.h.kahn@jpl.nasa.gov RI Wu, Dong/D-5375-2012 NR 60 TC 31 Z9 31 U1 1 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAR 1 PY 2007 VL 112 IS D5 AR D05202 DI 10.1029/2006JD007336 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 143GL UT WOS:000244708000003 ER PT J AU How, JP Breger, LS Mitchell, M Alfrien, KT Carpenter, R AF How, Jonathan P. Breger, Louis S. Mitchell, Megan Alfrien, Kyle T. Carpenter, Russell TI Differential semimajor axis estimation performance using carrier-phase differential global positioning system measurements SO JOURNAL OF GUIDANCE CONTROL AND DYNAMICS LA English DT Article; Proceedings Paper CT AIAA Guidance, Navigation and Control Conference CY AUG 16-19, 2004 CL Providence, RI SP AIAA AB This paper investigates the impact of navigation errors on the navigation and control aspects of formation flying spacecraft. The use of carrier-phase differential Global Positioning System measurements in relative navigation filters is analyzed, with a particular focus on the semimajor axis error. Semimajor axis error is shown to be the sum of two positive quantities that are related to the satisfaction of the balance and correlation requirements. Previous publications have suggested that a "good" navigation filter would yield estimates of the along-track velocity and radial position that are strongly correlated. However, practical experience with filters based on the carrier-phase differential Global Positioning System measurements has shown that this seldom occurs, even when the estimation accuracies are very good. Analytical methods and numerical simulations are used to show that the optimal semimajor axis estimate from a Kalman filter does not satisfy these requirements for any combination of measurement and process noise. Numerical examples with a fully nonlinear extended Kalman filter appear to bear out these conclusions. The combination of these simulations and analysis provides new insights on the crucial role of the process noise in determining semimajor axis knowledge. C1 MIT, Dept Aeronaut & Astronaut, Cambridge, MA 02139 USA. Texas A&M Univ, Dept Aerosp Engn, College Stn, TX 77843 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP How, JP (reprint author), MIT, Dept Aeronaut & Astronaut, 77 Massachusetts Ave, Cambridge, MA 02139 USA. EM jhow@mit.edu; lbreger@mit.edu; megan.mitchell@alum.mit.edu; alfriend@aero.tamu.edu; Russell.Carpenter@nasa.gov OI How, Jonathan/0000-0001-8576-1930 NR 17 TC 2 Z9 2 U1 1 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0731-5090 J9 J GUID CONTROL DYNAM JI J. Guid. Control Dyn. PD MAR-APR PY 2007 VL 30 IS 2 BP 301 EP 313 DI 10.2514/1.23083 PG 13 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA 150PK UT WOS:000245228500002 ER PT J AU Lara, M Russell, R Villac, B AF Lara, Martin Russell, Ryan Villac, Benjamin TI Classification of the distant stability regions at Europa SO JOURNAL OF GUIDANCE CONTROL AND DYNAMICS LA English DT Article; Proceedings Paper CT AIAA/AAS Astrodynamics Specialist Conference CY AUG 07-11, 2005 CL Lake Tahoe, CA SP Amer Inst Aeronaut & Astronaut, Amer Astronaut Soc ID PERIODIC-ORBITS; RESTRICTED PROBLEM; 3-BODY PROBLEM; EXPLORATION; SATELLITES; MASSES AB Long-term stable trajectories around Europa, one of the Galilean moons of Jupiter, are analyzed for their potential applications in spacecraft trajectory design, such as end-of-mission disposal options, backup orbits, or intermediary targets for transfer trajectories. The phase space is analyzed via the computation of families of periodic orbits and the estimation of their stability character. Although the core analysis of the paper uses the circular restricted three-body problem, a selected set of long-term stable solutions is checked by integrating the corresponding initial conditions in an ephemeris model over several years. The current model and methods can be readily applied to other planetary satellites including the other Galileans at Jupiter, the many satellites at Saturn, and the Earth's moon. C1 Real Observ Armada, Ephemeris Sect, San Fernando 11110, Spain. CALTECH, Jet Prop Lab, Guidance Navigat & Control Sect, Pasadena, CA 91109 USA. RP Lara, M (reprint author), Real Observ Armada, Ephemeris Sect, San Fernando 11110, Spain. EM mlara@roa.es; Ryan.Russell@jpl.nasa.gov; bvillac@uci.edu RI Lara, Martin/L-6291-2014 OI Lara, Martin/0000-0001-6754-916X NR 24 TC 17 Z9 17 U1 0 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0731-5090 J9 J GUID CONTROL DYNAM JI J. Guid. Control Dyn. PD MAR-APR PY 2007 VL 30 IS 2 BP 409 EP 418 DI 10.2514/1.22372 PG 10 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA 150PK UT WOS:000245228500012 ER PT J AU Russell, RP AF Russell, Ryan P. TI Primer vector theory applied to global low-thrust trade studies SO JOURNAL OF GUIDANCE CONTROL AND DYNAMICS LA English DT Article; Proceedings Paper CT AAS/AIAA 16th Space Flight Mechanics Meeting CY JAN 22-26, 2006 CL Tampa, FL SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut ID DIRECT TRAJECTORY OPTIMIZATION; COLLOCATION; SPACECRAFT; TRANSFERS; GUIDANCE; ORBITS AB The low-thrust spacecraft trajectory problem can be reduced to only a few parameters using calculus of variations and the well-known primer vector theory. This low dimensionality combined with the extraordinary speed of modern computers allows for rapid exploration of the parameter space and invites opportunities for global optimization. Accordingly, a general low-thrust trade analysis tool is developed based on a global search for local indirect method solutions. An efficient propagator is implemented with an implicit "bang-bang" thrusting structure that accommodates an a priori unknown number of switching times. An extension to the standard adjoint control transformation is introduced that provides additional physical insight and control over the anticipated evolution of the thrust profile. The uniformly random search enjoys a perfect linear speedup for parallel implementation. The method is applied specifically on multirevolution transfers in the Jupiter-Europa and Earth-moon restricted three body problems. In both cases, thousands of solutions are found in a single parallel run. The result is a global front of Pareto optimal solutions across the competing objectives of flight time and final mass. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Russell, RP (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,M-S 301-140L, Pasadena, CA 91109 USA. EM Ryan.Russell@jpl.nasa.gov NR 44 TC 39 Z9 43 U1 0 U2 9 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0731-5090 J9 J GUID CONTROL DYNAM JI J. Guid. Control Dyn. PD MAR-APR PY 2007 VL 30 IS 2 BP 460 EP 472 DI 10.2514/1.22984 PG 13 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA 150PK UT WOS:000245228500017 ER PT J AU Russell, RP Lam, T AF Russell, Ryan P. Lam, Try TI Designing ephemeris capture trajectories at Europa using unstable periodic orbits SO JOURNAL OF GUIDANCE CONTROL AND DYNAMICS LA English DT Article; Proceedings Paper CT AAS/AIAA 16th Space Flight Mechanics Meeting CY JAN 22-26, 2006 CL Tampa, FL SP Amer Astronaut Soc, Amer Inst Aeronaut & Astronaut ID PLANETARY SATELLITE ORBITERS; RESTRICTED 3-BODY PROBLEM; TRANSFERS; STABILITY; MOON AB Europa's proximity to Jupiter creates a hostile dynamic environment for a spacecraft with limited control authority as is typical with low-thrust missions. The unstable third-body effects are magnified near the polar inclinations where science orbits reside, and plane changes deep within Europa's gravity well are fuel and time expensive. Therefore, designing capture trajectories directly to highly inclined states is desirable but challenging because of the pronounced instability and lack of thrust authority. The approach outlined here confronts this problem by using dynamical systems theory and an extensive preexisting database of restricted three-body problem periodic orbits. The stable manifolds of unstable periodic orbits are used to attract a spacecraft towards Europa. By selecting an appropriate periodic orbit, a mission designer can control important characteristics of the captured state including stability, minimum altitudes, characteristic inclinations, and characteristic radii, among others. Several free parameters are adjusted in the nontrivial mapping from the simplified to a more realistic model until a satisfactory ephemeris capture is found. Although the final capture trajectory is ballistic by design, low thrust is used to target the state that leads to the capture orbit, control the spacecraft after arriving on the unstable quasi-periodic orbit, and begin the spiral down towards the science orbit. Despite the limited control authority and the highly unstable dynamical environment, the method provides structure to the design process and enables the systematic targeting of ephemeris model capture state characteristics. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Russell, RP (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,M-S 301-140L, Pasadena, CA 91109 USA. EM Ryan.Russell@jpl.nasa.gov; Try.Lam@jpl.nasa.gov NR 40 TC 14 Z9 14 U1 0 U2 3 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0731-5090 J9 J GUID CONTROL DYNAM JI J. Guid. Control Dyn. PD MAR-APR PY 2007 VL 30 IS 2 BP 482 EP 491 DI 10.2514/1.22985 PG 10 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA 150PK UT WOS:000245228500019 ER PT J AU Elias, LM Kwon, DW Sedwick, RJ Miller, DW AF Elias, Laila M. Kwon, Daniel W. Sedwick, Raymond J. Miller, David W. TI Electromagnetic formation flight dynamics including reaction wheel gyroscopic stiffening effects SO JOURNAL OF GUIDANCE CONTROL AND DYNAMICS LA English DT Article AB In this paper, we consider the equations of motion of a two-spacecraft formation flying array that uses electromagnets as relative position actuators. The relative positions of the spacecraft are controlled by the forces generated between the electromagnets on the two spacecraft, and the attitudes of the spacecraft are controlled using reaction wheels. The nonlinear equations of motion for this system are linearized about a nominal operating trajectory, taken to be a steady-state spin maneuver used for deep-space interferometric observation. The linearized equations are analyzed for stability and controllability. Although the open-loop system proves to be unstable, a controllability analysis indicates that the system is fully controllable with the given suite of actuators, and is therefore stabilizable. An optimal linear feedback controller is then designed, and the closed-loop dynamics are simulated. The simulations demonstrate that the closed-loop system is indeed stable, and that linear control is a very promising technique for electromagnetic formation flight systems, despite the nonlinearity of the dynamics. C1 MIT, Dept Aeronaut & Astronaut, Cambridge, MA 02139 USA. MIT, Space Syst Lab, Cambridge, MA 02139 USA. RP Elias, LM (reprint author), CALTECH, Jet Prop Lab, Guidance & Control Anal Grp, M-S 198-326, Pasadena, CA 91109 USA. NR 8 TC 25 Z9 29 U1 0 U2 4 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0731-5090 J9 J GUID CONTROL DYNAM JI J. Guid. Control Dyn. PD MAR-APR PY 2007 VL 30 IS 2 BP 499 EP 511 DI 10.2514/1.18679 PG 13 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA 150PK UT WOS:000245228500021 ER PT J AU Kukreja, SL Brenner, MJ AF Kukreja, Sunil L. Brenner, Martin J. TI Nonlinear black-box modeling of aeroelastic systems using structure detection: Application to F/A-18 data SO JOURNAL OF GUIDANCE CONTROL AND DYNAMICS LA English DT Article ID NON-LINEAR SYSTEMS; PARAMETER-ESTIMATION ALGORITHMS; NARMAX MODELS; IDENTIFICATION; REGRESSION; SELECTION AB Structure detection is a procedure for selecting a subset of candidate terms, from a full model description, that best describes the observed output. This is a necessary procedure to compute an efficient system description which may afford greater insight into the functionality of the system or a simpler controller design. Structure computation as a tool for "black-box" modeling is not well known to the flight-test community but may be of critical importance in the development of robust, parsimonious models. Moreover, this approach may lead to efficient strategies for rapid envelope expansion which may save significant development time and costs. Structure detection methods applicable to nonlinear autoregressive, moving average exogenous modeling are applied to aeroelastic dynamics and their properties demonstrated via continuous-time simulations of experimental conditions. Simulation results from a nonlinear dynamic model of aircraft structural free-play demonstrate that methods developed for nonlinear autoregressive, moving average exogenous structure computation provide a high degree of accuracy for selection of the exact model structure from an overparameterized model description. Applicability of these methods to the F/A-18 active aeroelastic wing using flight-test data is shown by identifying a parsimonious system description with a high percent fit for cross-validated data. C1 NASA, Dryden Flight Res Ctr, Struct Dynam Grp, Aerostruct Branch, Edwards AFB, CA 93523 USA. RP Kukreja, SL (reprint author), NASA, Dryden Flight Res Ctr, Struct Dynam Grp, Aerostruct Branch, MailStop 4820 2A, Edwards AFB, CA 93523 USA. EM sunil.kukreja@nasa.gov NR 45 TC 3 Z9 6 U1 1 U2 3 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0731-5090 J9 J GUID CONTROL DYNAM JI J. Guid. Control Dyn. PD MAR-APR PY 2007 VL 30 IS 2 BP 557 EP 564 DI 10.2514/1.20835 PG 8 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA 150PK UT WOS:000245228500027 ER PT J AU Jerebets, S Liu, YM Liu, FC Ahlers, G AF Jerebets, Sergei Liu, Yuanming Liu, Fengchuan Ahlers, Guenter TI Finite-size effects on the thermal resistivity of He-4 near the superfluid transition SO JOURNAL OF LOW TEMPERATURE PHYSICS LA English DT Article ID RENORMALIZATION-GROUP THEORY; T-LAMBDA; BOUNDARY RESISTANCE; KAPITZA RESISTANCE; CONFINED HE-4; CONDUCTIVITY; UNIVERSALITY; SINGULARITY; GOLD AB We present measurements of the thermal resistivity rho(t, L) (t T/T lambda-1) near the superfluid transition temperature T-lambda of He-4 at saturated vapor pressure and confined in glass capillary arrays with rectangular capillary cross-sections of spacing L = 1 mu m, width w = 10 mu m, and length d similar or equal to 1 mm. We expect the finite-size effect in this rectangular geometry to provide a good approximation to that in the ideal parallel-plate geometry. The data coincide within our resolution with previous measurements for cylindrical capillaries of 1 mu m radius, indicating that the finite-size scaling-functions for these two geometries are indistinguishable. This stands in contrast to the scaling functions for static properties which, near the transition temperature, depend on the dimensionality of the confinement. The results are consistent with recent Monte Carlo and spin-dynamics simulations, and with renormalization-group calculations for capillaries with square cross section and t >= 0. C1 CALTECH, Jet Propuls Lab, Pasadena, CA 91109 USA. Univ Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USA. Univ Calif Santa Barbara, iQCD, Santa Barbara, CA 93106 USA. RP Jerebets, S (reprint author), CALTECH, Jet Propuls Lab, Pasadena, CA 91109 USA. EM jerebets@jpl.nasa.gov; guenter@physics.ucsb.edu NR 35 TC 1 Z9 1 U1 0 U2 1 PU SPRINGER/PLENUM PUBLISHERS PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0022-2291 J9 J LOW TEMP PHYS JI J. Low Temp. Phys. PD MAR PY 2007 VL 146 IS 5-6 BP 471 EP 483 DI 10.1007/s10909-006-9278-5 PG 13 WC Physics, Applied; Physics, Condensed Matter SC Physics GA 137RT UT WOS:000244310400004 ER PT J AU Nerger, L Danilov, S Kivman, G Hiller, W Schroter, J AF Nerger, L. Danilov, S. Kivman, G. Hiller, W. Schroeter, J. TI Data assimilation with the Ensemble Kalman Filter and the SEIK filter applied to a finite element model of the North Atlantic SO JOURNAL OF MARINE SYSTEMS LA English DT Article; Proceedings Paper CT 36th International Liege Colloquium on Ocean Dynamics CY MAY 03-07, 2004 CL Liege, BELGIUM DE data assimilation; Kalman filter; Ensemble Kalman Filter; SEIK filter; North Atlantic ID SEQUENTIAL DATA ASSIMILATION AB Currently there are different approaches to filter algorithms based on the Kalman filter. One of the most used filter algorithms is the Ensemble Kalman Filter (EnKF). It uses a Monte Carlo approach to the filtering problem. Another approach is given by the Singular Evolutive Extended Kalman (SEEK) and Singular Evolutive Interpolated Kalman (SEIK) filters. These filters operate explicitly on a low-dimensional error space which is represented by an ensemble of model states. The EnKF and the SEIK filter have been implemented within a parallel data assimilation framework in the Finite Element Ocean Model FEOM. In order to compare the filter performances of the algorithms, several data assimilation experiments are performed. The filter algorithms have been applied with a model configuration of FEOM for the North Atlantic to assimilate the sea surface height in twin experiments. The dependence of the filter estimates on the represented error subspace is discussed. In the experiments the SEIK algorithm provides better estimates than the EnKF. Furthermore, the SEEK filter is much cheaper in terms of computing time. (c) 2006 Elsevier B.V. All rights reserved. C1 Alfred Wegener Inst Polar & Marine Res, D-2850 Bremerhaven, Germany. RP Nerger, L (reprint author), NASA, Goddard Space Flight Ctr, Goddard Earth Sci & Technol Ctr, Greenbelt, MD 20771 USA. EM lnerger@awi-bremerhaven.de RI Nerger, Lars/G-4845-2013; Danilov, Sergey/S-6184-2016 OI Nerger, Lars/0000-0002-1908-1010; NR 17 TC 11 Z9 11 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0924-7963 J9 J MARINE SYST JI J. Mar. Syst. PD MAR PY 2007 VL 65 IS 1-4 BP 288 EP 298 DI 10.1016/j.jmarsys.2005.06.009 PG 11 WC Geosciences, Multidisciplinary; Marine & Freshwater Biology; Oceanography SC Geology; Marine & Freshwater Biology; Oceanography GA 147LB UT WOS:000245003400017 ER PT J AU Yamakov, V Saether, E Phillips, DR Glaessgen, EH AF Yamakov, V. Saether, E. Phillips, D. R. Glaessgen, E. H. TI Dynamics of nanoscale grain-boundary decohesion in aluminum by molecular-dynamics simulation SO JOURNAL OF MATERIALS SCIENCE LA English DT Article; Proceedings Paper CT Nanomaterisls - Materials and Processing for Functional Applications held at the 2006 TMS Spring Meeting CY MAR 13-16, 2006 CL San Antonio, TX SP TMS ID CRACK-TIP; INTERGRANULAR FRACTURE; NANOCRYSTALLINE MATERIALS; ATOMISTIC SIMULATION; ENERGY-DISSIPATION; DEFORMATION; DISLOCATION; NUCLEATION; METALS; PROPAGATION AB The dynamics and energetics of intergranular crack growth along a flat grain boundary in aluminum is studied by a molecular-dynamics simulation model for crack propagation under steady-state conditions. Using the ability of the molecular-dynamics simulation to identify atoms involved in different atomistic mechanisms, it was possible to identify the energy contribution of different processes taking place during crack growth. The energy contributions were divided as: elastic energy-defined as the potential energy of the atoms in fcc crystallographic state; and plastically stored energy-the energy of stacking faults and twin boundaries; grain-boundary and surface energy. In addition, monitoring the amount of heat exchange with the molecular-dynamics thermostat gives the energy dissipated as heat in the system. The energetic analysis indicates that the majority of energy in a fast growing crack is dissipated as heat. This dissipation increases linearly at low speed, and faster than linear at speeds approaching 1/3 the Rayleigh wave speed when the crack tip becomes dynamically unstable producing periodic dislocation bursts until the crack is blunted. C1 Natl Inst Aerosp, Hampton, VA 23666 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. Lockheed Martin Space Operat, Hampton, VA 23681 USA. RP Yamakov, V (reprint author), Natl Inst Aerosp, Hampton, VA 23666 USA. EM yamakov@nianet.org NR 38 TC 13 Z9 13 U1 1 U2 17 PU SPRINGER PI NEW YORK PA 233 SPRING STREET, NEW YORK, NY 10013 USA SN 0022-2461 J9 J MATER SCI JI J. Mater. Sci. PD MAR PY 2007 VL 42 IS 5 BP 1466 EP 1476 DI 10.1007/s10853-006-1176-3 PG 11 WC Materials Science, Multidisciplinary SC Materials Science GA 142WZ UT WOS:000244683100009 ER PT J AU Tahmasebi, F AF Tahmasebi, Farhad TI Kinematics of a new high-precision three-degree-of-freedom parallel manipulator SO JOURNAL OF MECHANICAL DESIGN LA English DT Article; Proceedings Paper CT ASME 2005 Design Engineering Technical Conferences/Computers and Information in Engineering Conferences (DETC 2005) CY SEP 24-28, 2005 CL Long Beach, CA ID STEWART PLATFORM; POSITION ANALYSIS; MECHANISM; MINIMANIPULATOR AB Closed-form direct and inverse kinematics of a new three-degree-of-freedom (DOF) parallel manipulator with inextensible limbs and base-mounted actuators are presented. The manipulator has higher resolution and precision than the existing three-DOF mechanisms with extensible limbs. Since all of the manipulator actuators are base mounted, higher payload capacity, smaller actuator sizes, and lower power dissipation can be obtained. The manipulator is suitable for alignment applications where only tip, tilt, and piston motions are significant. The direct kinematics of the manipulator is reduced to solving an eighth-degree polynomial in the square of the tangent of the half-angle between one of the limbs and the base plane. Hence, there are atmost 16 assembly configurations for the manipulator In addition, it is shown that the 16 solutions are eight pairs of reflected configurations with respect to the base plane. Numerical examples for the direct and inverse kinematics of the manipulator are also presented. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Tahmasebi, F (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. EM Farhad.Tahmasebi@nasa.gov NR 29 TC 7 Z9 7 U1 1 U2 5 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA THREE PARK AVE, NEW YORK, NY 10016-5990 USA SN 1050-0472 J9 J MECH DESIGN JI J. Mech. Des. PD MAR PY 2007 VL 129 IS 3 BP 320 EP 325 DI 10.1115/1.2406103 PG 6 WC Engineering, Mechanical SC Engineering GA 146HT UT WOS:000244925800010 ER PT J AU Nickerson, CA Richter, EG Ott, CM AF Nickerson, Cheryl A. Richter, Emily G. Ott, C. Mark TI Studying host-pathogen interactions in 3-D: Organotypic models for infectious disease and drug development SO JOURNAL OF NEUROIMMUNE PHARMACOLOGY LA English DT Review DE three-dimensional (3-D) cell culture; physiologically relevant models; host-pathogen interaction; infectious disease; drug discovery ID MICROGRAVITY; CULTURE; CELLS; DIMENSION; INVASION AB Representative, reproducible, and high-throughput models of human cells and tissues are critical for a meaningful evaluation of host-pathogen interactions and are an essential component of the research developmental pipeline. The most informative infection models-animals, organ explants, and human trials-are not suited for extensive evaluation of pathogenesis mechanisms and screening of candidate drugs. At the other extreme, more cost-effective and accessible infection models such as conventional cell culture and static coculture may not capture physiological and three-dimensional (3-D) aspects of tissue biology that are important in assessing pathogenesis, effectiveness, and cytotoxicity of therapeutics. Our lab has used innovative bioengineering technology to establish biologically meaningful 3-D models of human tissues that recapitulate many aspects of the differentiated structure and function of the parental tissue in vivo, and we have applied these models to study infectious disease. We have established a variety of different 3-D models that are currently being used in infection studies-including small intestine, colon, lung, placenta, bladder, periodontal ligament, and neuronal models. Published work from our lab has shown that our 3-D models respond to infection with bacterial and viral pathogens in ways that reflect the infection process in vivo. By virtue of their physiological relevance, 3D cell cultures may also hold significant potential to provide insight into the neuropathogenesis of HIV infection. Furthermore, the experimental flexibility, reproducibility, cost efficiency, and high-throughput platform afforded by these 3-D models may have important implications for the design and development of drugs with which to effectively treat neurological complications of HIV infection. C1 Arizona State Univ, Biodesign Inst, Ctr Infect Dis & Vaccinol, Tempe, AZ 85287 USA. NASA, Lyndon B Johnson Space Ctr, Habitabil & Environm Factors Off, Houston, TX 77058 USA. RP Nickerson, CA (reprint author), Arizona State Univ, Biodesign Inst, Ctr Infect Dis & Vaccinol, POB 875401, Tempe, AZ 85287 USA. EM cheryl.nickerson@asu.edu NR 15 TC 37 Z9 37 U1 5 U2 10 PU SPRINGER PI NEW YORK PA 233 SPRING STREET, NEW YORK, NY 10013 USA SN 1557-1890 J9 J NEUROIMMUNE PHARM JI J. Neuroimmune Pharm. PD MAR PY 2007 VL 2 IS 1 BP 26 EP 31 DI 10.1007/s11481-006-9047-x PG 6 WC Neurosciences; Pharmacology & Pharmacy SC Neurosciences & Neurology; Pharmacology & Pharmacy GA 201YW UT WOS:000248869500006 PM 18040823 ER PT J AU Miele, A Weeks, MW Ciarcia, M AF Miele, A. Weeks, M. W. Ciarcia, M. TI Optimal trajectories for spacecraft rendezvous SO JOURNAL OF OPTIMIZATION THEORY AND APPLICATIONS LA English DT Article DE space trajectories; rendezvous; optimal control; calculus of variations; Mayer problems; Bolza problems; transformation techniques; sequential gradient-restoration algorithm ID GRADIENT-RESTORATION ALGORITHM; OPTIMAL 2-IMPULSE; PRIMER VECTOR; EQUATIONS; MOTION; ORBIT AB The efficient execution of a rendezvous maneuver is an essential component of various types of space missions. This work describes the formulation and numerical investigation of the thrust function required to minimize the time or fuel required for the terminal phase of the rendezvous of two spacecraft. The particular rendezvous studied concerns a target spacecraft in a circular orbit and a chaser spacecraft with an initial separation distance and separation velocity in all three dimensions. First, the time-optimal rendezvous is investigated followed by the fuel-optimal rendezvous for three values of the max-thrust acceleration via the sequential gradient-restoration algorithm. Then, the time-optimal rendezvous for given fuel and the fuel-optimal rendezvous for given time are investigated. There are three controls, one determining the thrust magnitude and two determining the thrust direction in space. The time-optimal case results in a two-subarc solution: a max- thrust accelerating subarc followed by a max-thrust braking subarc. The fuel-optimal case results in a four-subarc solution: an initial coasting subarc, followed by a max- thrust braking subarc, followed by another coasting subarc, followed by another max-thrust braking subarc. The time-optimal case with fuel given and the fuel-optimal case with time given result in two, three, or four-subarc solutions depending on the performance index and the constraints. Regardless of the number of subarcs, the optimal thrust distribution requires the thrust magnitude to be at either the maximum value or zero. The coasting periods are finite in duration and their length increases as the time to rendezvous increases and/or as the max allowable thrust increases. Another finding is that, for the fuel-optimal rendezvous with the time unconstrained, the minimum fuel required is nearly constant and independent of the max available thrust. Yet another finding is that, depending on the performance index, constraints, and initial conditions, sometime the initial application of thrust must be delayed, resulting in an optimal rendezvous trajectory which starts with a coasting subarc. C1 Rice Univ, Aeroastronaut Grp, Houston, TX 77251 USA. NASA, Lyndon B Johnson Space Ctr, Aerosci & Flight Mech Div, Houston, TX 77058 USA. RP Miele, A (reprint author), Rice Univ, Aeroastronaut Grp, Houston, TX 77251 USA. EM miele@rice.edu NR 42 TC 17 Z9 22 U1 0 U2 5 PU SPRINGER/PLENUM PUBLISHERS PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0022-3239 J9 J OPTIMIZ THEORY APP JI J. Optim. Theory Appl. PD MAR PY 2007 VL 132 IS 3 BP 353 EP 376 DI 10.1007/s10957-007-9166-4 PG 24 WC Operations Research & Management Science; Mathematics, Applied SC Operations Research & Management Science; Mathematics GA 192MI UT WOS:000248205700001 ER PT J AU Miele, A Ciarcia, M Weeks, MW AF Miele, A. Ciarcia, M. Weeks, M. W. TI Guidance trajectories for spacecraft rendezvous SO JOURNAL OF OPTIMIZATION THEORY AND APPLICATIONS LA English DT Article DE space trajectories; rendezvous; guidance; optimal control; calculus of variations; Mayer problems; Bolza problems; transformation techniques; multiple-subarc sequential gradient restoration algorithm ID GRADIENT-RESTORATION ALGORITHM; OPTIMAL 2-IMPULSE; PRIMER VECTOR; EQUATIONS; MOTION; ORBIT AB In a previous paper of Miele et al. (J. Optim. Theory Appl. 132(1), 2007), we employed the single-subarc sequential gradient- restoration algorithm to optimize the three-dimensional rendezvous between a target spacecraft in a planar circular orbit and a chaser spacecraft with an initial separation distance and separation velocity. The achieved continuous solutions are characterized by two, three, or four subarcs depending on the performance index (time, fuel) and the constraints. In this paper, based on the solutions in Miele et al. (J. Optim. Theory Appl. 132(1), 2007), we employ the multiple- subarc sequential gradient- restoration algorithm to produce pieced guidance trajectories implementable in real time via constant control components. In other words, in this investigation, we force the controls to behave as parameters in each subarc. With the above understanding, we investigate four problems: (P1) minimum time, fuel free; (P2) minimum fuel, time free; (P3) minimum time, fuel given; (P4) minimum fuel, time given. Problem P1 results in a two- subarc solution, each subarc with constant controls: a max-thrust accelerating subarc followed by a max-thrust braking subarc. Problem P2 results in a four-subarc solution, each subarc with constant controls: an initial coasting subarc, followed by a max-thrust braking subarc, followed by another coasting subarc, followed by another max-thrust braking subarc. Problems P3 and P4 result in two, three, or four-subarc solutions depending on the performance index and the constraints, albeit with constant controls in each subarc. For each of the problems studied, the performance index of the multiple-subarc pieced guidance trajectory approximates well the performance index of the singlesubarc continuous optimal trajectory of Miele et al. (J. Optim. Theory Appl. 132(1), 2007) as well as the performance index of the multiple-subarc pieced optimal trajectory: the pairwise relative differences in performance index are less than 1/100. C1 Rice Univ, Aeroastronaut Grp, Houston, TX 77251 USA. NASA, Lyndon B Johnson Space Ctr, Aerosci & Flight Mech Div, Houston, TX 77058 USA. RP Miele, A (reprint author), Rice Univ, Aeroastronaut Grp, Houston, TX 77251 USA. EM miele@rice.edu NR 32 TC 9 Z9 12 U1 1 U2 6 PU SPRINGER/PLENUM PUBLISHERS PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0022-3239 J9 J OPTIMIZ THEORY APP JI J. Optim. Theory Appl. PD MAR PY 2007 VL 132 IS 3 BP 377 EP 400 DI 10.1007/s10957-007-9165-5 PG 24 WC Operations Research & Management Science; Mathematics, Applied SC Operations Research & Management Science; Mathematics GA 192MI UT WOS:000248205700002 ER PT J AU Fu, LL AF Fu, Lee-Lueng TI Interaction of mesoscale variability with large-scale waves in the Argentine Basin SO JOURNAL OF PHYSICAL OCEANOGRAPHY LA English DT Article ID MALVINAS CURRENTS; SOUTH-ATLANTIC; BRAZIL; OCEAN; TOPEX/POSEIDON; OSCILLATIONS; CONFLUENCE; ALTIMETER; EDDIES; PERIOD AB The Argentine Basin of the South Atlantic Ocean is a region of complicated ocean dynamics involving a wide range of spatial and temporal scales. Previous studies reported the existence of a basin mode of topographic barotropic Rossby waves with a period close to 25 days in the region. Using observations of sea level anomalies from satellite altimeter measurements, the present study provides evidence of interaction between the large-scale 25-day waves and the energetic mesoscale variability of the region. The amplitude of the 25-day waves is highly intermittent with dominant periods in the range of 110-150 days. Within this period band, the wave amplitude is coherent with the energy level of the mesoscale variability: when the mesoscale energy level goes down, the wave amplitude goes up, and vice versa, suggesting an exchange of energy between the two scales. This coherence is linked to the first three empirical orthogonal functions (EOFs) of the sea level anomalies. The spatial patterns of these EOFs are characterized by eddies and meanders associated with the Brazil-Malvinas Confluence. The findings of the study suggest a mechanism of energy exchange at work between the mesoscale variability and the large-scale waves in the Argentine Basin. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Fu, LL (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 300-323, Pasadena, CA 91109 USA. EM llf@pacific.jpl.nasa.gov NR 14 TC 10 Z9 10 U1 0 U2 4 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-3670 J9 J PHYS OCEANOGR JI J. Phys. Oceanogr. PD MAR PY 2007 VL 37 IS 3 BP 787 EP 793 DI 10.1175/JPO2991.1 PG 7 WC Oceanography SC Oceanography GA 156DU UT WOS:000245629100021 ER PT J AU Kumar, K Freeh, JE Sung, CJ Huang, Y AF Kumar, K. Freeh, J. E. Sung, C. J. Huang, Y. TI Laminar flame speeds of preheated iso-octane/O-2/N-2 and n-heptane/O-2/N-2 mixtures SO JOURNAL OF PROPULSION AND POWER LA English DT Article ID PARTICLE IMAGE VELOCIMETRY; N-HEPTANE OXIDATION; ISOOCTANE FLAMES; COUNTERFLOW; PROPAGATION; SURROGATE; FUELS; JP-8 AB Laminar flame speed measurements are carried out for premixed iso-octane/air and n-heptane/air mixtures under conditions of atmospheric pressure, equivalence ratios ranging from 0.7 to 1.4, and unburned mixture temperatures of 298, 360, 400, and 470 K using the counterflow flame technique. These experiments employ the digital particle image velocimetry technique to characterize the two-dimensional flow field upstream of the flame. As such, the reference stretch-affected flame speed and the imposed stretch rate can be simultaneously determined. By systematically varying the imposed stretch rate, the corresponding laminar flame speed is obtained by linearly extrapolating to zero stretch rate. In addition, the effect of nitrogen dilution level on the laminar flame speed is investigated by varying the nitrogen molar percentage in the oxidizer mixture from 78.5 to 80.5%. These results are further used for the determination of overall activation energies at different equivalence ratios. The experimental laminar flame speeds are subsequently compared with the computed values using two iso-octane reaction mechanisms and two n-heptane reaction mechanisms available in the literature, followed by discussion and sensitivity analysis. C1 Case Western Reserve Univ, Dept Mech & Aerosp Engn, Cleveland, OH 44106 USA. NASA, Lewis Res Ctr, Syst Anal Off, Cleveland, OH 44135 USA. RP Sung, CJ (reprint author), Case Western Reserve Univ, Dept Mech & Aerosp Engn, Cleveland, OH 44106 USA. EM cjsl5@case.edu OI Kumar, Kamal/0000-0002-3923-8740 NR 29 TC 71 Z9 79 U1 0 U2 10 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0748-4658 J9 J PROPUL POWER JI J. Propul. Power PD MAR-APR PY 2007 VL 23 IS 2 BP 428 EP 436 DI 10.2514/1.24391 PG 9 WC Engineering, Aerospace SC Engineering GA 147DN UT WOS:000244983700021 ER PT J AU Rinsland, CP Goldman, A Hannigan, JW Wood, SW Chiou, LS Mahieu, E AF Rinsland, Curtis P. Goldman, Aaron Hannigan, James W. Wood, Stephen W. Chiou, Linda S. Mahieu, Emmanuel TI Long-term trends of tropospheric carbon monoxide and hydrogen cyanide from analysis of high resolution infrared solar spectra SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Article DE remote sensing; troposphere; atmospheric chemistry; carbon monoxide; hydrogen cyanide; pollution ID VERTICAL COLUMN ABUNDANCES; BOREAL FOREST-FIRES; SPECTROSCOPIC MEASUREMENTS; MULTISPECTRUM ANALYSIS; NORTHERN-HEMISPHERE; SEASONAL-VARIATIONS; CENTRAL-EUROPE; V(1) BAND; KITT PEAK; HCN AB Long-term trend and seasonal variation of the mean free tropospheric volume mixing ratios of carbon monoxide (CO) and hydrogen cyanide (HCN) have been derived from analysis of a time series of solar absorption spectra recorded from the US National Solar Observatory on Kitt Peak (31.9 degrees N, 111.6 degrees W, 2.09 km altitude) spanning almost three decades. The results of a fit to the CO 258 daily averages from May 1977 to April 2005 as a function of time with a model that assumes a sinusoidal seasonal cycle and a linear long-term trend with time yield a mean volume mixing ratio of 102 +/- 3) parts per billion (10(-9) per unit volume) below 10km altitude, I sigma. The CO measurements show a seasonal cycle with a maximum in March and a minimum in September with an amplitude of (22.3 +/- 1.5)% relative to the mean. The best-fit corresponds to a long-term CO trend of (0.15 +/- 0.14)% yr(-1), 1 sigma, relative to the mean. To quantify the possible impact of periods of intense fires, the CO measurements have been compared with the measurements of HCN, a well-documented emission product of biomass burning with a lifetime of similar to 5 months. The best fit to the full HCN time series of 208 daily averages from May 1978 to April 2005 results in a mean volume mixing ratio of (0.219 +/- 0.007) ppbv below 10 km altitude with a similar seasonal cycle, though with a lower relative amplitude than for CO. Although same-day enhancements up to a factor of 1.87 for HCN and 1.24 for CO were measured relative to values predicted by a fit to the time series that accounts for the seasonal cycles and trends of both molecules, excluding time periods of elevated fire emissions has no significant impact on the best-fit long-term free tropospheric CO and HCN trends. Our result of no long-term CO trend since the late 1970s suggests that the global average long-term decline reported from 1990 through 1995 measurements has not continued in the free troposphere. Similarly, a fit to the full time series of 208 HCN free tropospheric daily averages with the same model yields an average 2.09-10km mixing ratio of 0.219ppbv and a long-term trend of (-0.12 +/- 0.14) % yr(-1), 1 sigma, relative to the mean since 1978, also indicating no significant long-term trend above the lower mid-latitude continental US Kitt Peak station. The results for both molecules suggest the site was not significantly impacted by summer boreal fires during the time span of the measurements that in some years cause widespread pollution above northern higher latitude sites. (c) 2006 Elsevier Ltd. All rights reserved. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. Univ Denver, Dept Phys, Denver, CO 80208 USA. Natl Ctr Atmospher Res, Div Atmospher Chem, Boulder, CO 80307 USA. Natl Inst Water & Atmospher Res Ltd, Lauder, Omakau, Central Otago, New Zealand. Sci Applicat Int Corp, Hampton, VA USA. Univ Liege, Inst Astrophys & Geophys, B-4000 Liege, Belgium. RP Rinsland, CP (reprint author), NASA, Langley Res Ctr, Mail Stop 401A, Hampton, VA 23681 USA. EM c.p.rinsland@larc.nasa.gov OI Mahieu, Emmanuel/0000-0002-5251-0286 NR 60 TC 6 Z9 6 U1 1 U2 4 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0022-4073 J9 J QUANT SPECTROSC RA JI J. Quant. Spectrosc. Radiat. Transf. PD MAR PY 2007 VL 104 IS 1 BP 40 EP 51 DI 10.1016/j.jqsrt.2006.08.008 PG 12 WC Optics; Spectroscopy SC Optics; Spectroscopy GA 115UG UT WOS:000242758700004 ER PT J AU Moss, JN AF Moss, James N. TI Direct simulation Monte Carlo simulations of ballute aerothermodynamics under hypersonic rarefied conditions SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article; Proceedings Paper CT AIAA 38th Thermophysics Conference CY JUN 06-09, 2005 CL Toronto, CANADA SP Amer Inst Aeronaut & Astronaut AB This paper presents computational results obtained with the direct simulation Monte Carlo method for towed ballute applications. A ballute is an inflatable drag device that can be used to create a large amount of drag at high altitudes. Consequently, ballutes provide a potential technology for achieving aerocapture when the primary spacecraft velocity reduction (Delta V) is achieved at much higher altitudes than with the conventional rigid aeroshell. Because the Delta V is achieved at relatively high altitudes, rarefaction can be significant and is the motivation for the current study with the direct simulation Monte Carlo method. Computed surface and flowfield results are presented for a toroidal ballute, isolated tethers when exposed to freestream flow conditions, and the flow interactions resulting from a toroidal ballute when towed by a 6 m diameter Mars Pathfinder shaped (without tethers) spacecraft. All results presented are for Earth entry at velocities of 14 to 7 km/s (primary focus is at 8.55 km/s, same as some previous Titan aerocapture studies) and altitudes of 200 to 100 km. Variations of drag and heating coefficients as a function of rarefaction are presented. A description of the flow structure is provided and also an explanation of how it is affected by shock interactions produced solely by the ballute and those resulting from the two body combination of towed ballute and spacecraft is also given. C1 NASA, Langley Res Ctr, Aerothermodynam Branch, Hampton, VA 23681 USA. RP Moss, JN (reprint author), NASA, Langley Res Ctr, Aerothermodynam Branch, Mail Stop 408A, Hampton, VA 23681 USA. EM j.n.moss@larc.nasa.gov NR 17 TC 5 Z9 6 U1 0 U2 2 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD MAR-APR PY 2007 VL 44 IS 2 BP 289 EP 298 DI 10.2514/1.22706 PG 10 WC Engineering, Aerospace SC Engineering GA 155WW UT WOS:000245610300001 ER PT J AU Saltzman, EJ Wang, KC Iliff, KW AF Saltzman, Edwin J. Wang, K. Charles Iliff, Kenneth W. TI In-flight subsonic lift and drag characteristics unique to blunt-based lifting Reentry vehicles' SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article; Proceedings Paper CT AIAA 37th Aerospace Sciences Meeting and Exhibit CY JAN 11-14, 1999 CL RENO, NV SP Amer Inst Aeronaut & Astronaut AB Lift and drag measurements have been analyzed for subsonic flight conditions for seven blunt-based reentry-type vehicles. Five of the vehicles are lifting bodies (M2-F1, M2-F2, HL-10, X-24A, and X-24B) and two are wing-body configurations (the X-15 and the Space Shuttle Enterprise). Base pressure measurements indicate that the base drag for full-scale vehicles is approximately three times greater than predicted by Hoerner's equation for three-dimensional bodies. Base drag and forebody drag combine to provide an optimal overall minimum drag (a drag "bucket") for a given configuration. The magnitude of this optimal drag, as well as the associated forebody drag, is dependent on the ratio of base area to vehicle wetted area. Counterintuitively, the flight-determined optimal minimum drag does not occur at the point of minimum forebody drag, but at a higher forebody drag value. It was also found that the chosen definition for reference area for lift parameters should include the projection of planform area ahead of the wing trailing edge (i.e., forebody plus wing). Results are assembled collectively to provide a greater understanding of this class of vehicles than would occur by considering them individually. C1 NASA, Dryden Flight Res Ctr, Edwards AFB, CA 93523 USA. CALTECH, Jet Prop Lab, Mech Syst Div, Pasadena, CA 91109 USA. RP Saltzman, EJ (reprint author), NASA, Dryden Flight Res Ctr, POB 273, Edwards AFB, CA 93523 USA. NR 53 TC 0 Z9 0 U1 1 U2 3 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD MAR-APR PY 2007 VL 44 IS 2 BP 299 EP 309 DI 10.2514/1.18365 PG 11 WC Engineering, Aerospace SC Engineering GA 155WW UT WOS:000245610300002 ER PT J AU Braun, RD Manning, RM AF Braun, Robert D. Manning, Robert M. TI Mars exploration entry, descent and landing challenges SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article ID SIZE-FREQUENCY DISTRIBUTIONS; SITES AB The United States has successfully landed five robotic systems on the surface of Mars. These systems all had landed masses below 0.6 metric tons, had landed footprints on the order of hundreds of kilometers, and landed at sites below -1.4 kilometers elevation due the need to perform entry, descent, and landing operations in an environment with sufficient atmospheric density. At present, robotic exploration systems engineers are struggling with the challenges of increasing landed mass capability to 0.8 metric tons while improving landed accuracy to 10 kilometers and landing at a site as high as +2 kilometers elevation for the Mars science laboratory project. Meanwhile, current plans for human exploration of Mars call for the landing of 40-80 metric tons surface elements at scientifically interesting locations within close proximity (tens of meters) of pre-positioned robotic assets. This paper summarizes past successful entry, descent, and landing systems and approaches being developed by the robotic Mars exploration program to increase landed performance (mass, accuracy, and surface elevation). In addition, the entry, descent, and landing sequence for a human exploration system will be reviewed, highlighting the technology and systems advances required. C1 Georgia Inst Technol, Guggenheim Sch Aerosp Engn, Atlanta, GA 30332 USA. CALTECH, Jet Prop Lab, NASA, Mars Explorat Program, Pasadena, CA 91109 USA. RP Braun, RD (reprint author), Georgia Inst Technol, Guggenheim Sch Aerosp Engn, Atlanta, GA 30332 USA. NR 32 TC 162 Z9 189 U1 6 U2 20 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD MAR-APR PY 2007 VL 44 IS 2 BP 310 EP 323 DI 10.2514/1.25116 PG 14 WC Engineering, Aerospace SC Engineering GA 155WW UT WOS:000245610300003 ER PT J AU Oh, DY AF Oh, David Y. TI Evaluation of solar electric propulsion technologies for discovery-class missions SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article; Proceedings Paper CT AIAA/ASME/SAE/ASEE 41st Joint Propulsion Conference CY JUL 10-13, 2005 CL Tucson, AZ SP AIAA, ASME, SAE, ASEE ID SAMPLE; RETURN AB A detailed study examines the potential benefits that advanced electric propulsion technologies offer to cost-capped missions in NASA's Discovery program. The study looks at potential cost and performance benefits provided by three electric propulsion technologies that are currently in development: NASA's evolutionary xenon thruster, an enhanced NSTAR system, and a low-power Hall effect thruster. These systems are analyzed on three potential Discovery-class missions and their performance is compared with a state-of-the-art system using the NSTAR ion thruster. An electric propulsion subsystem cost model is used to conduct a cost-benefit analysis for each option. The results show that each proposed technology offers a different degree of performance and/or cost benefit for Discovery-class missions. However, lower subsystem costs (particularly, power processing and digital control interface unit costs) are needed for ion thruster systems, to make them more competitive for cost-capped missions. It is observed that the best mass performance generally comes from electric propulsion systems that best use available solar array power during the mission. Finally, first-flight qualification costs are identified as a significant barrier to the implementation of new electric propulsion technologies on cost-capped missions. C1 CALTECH, Jet Prop Lab, Astron & Explorat Concepts Grp, Pasadena, CA 91109 USA. RP Oh, DY (reprint author), CALTECH, Jet Prop Lab, Astron & Explorat Concepts Grp, 4800 Oak Grove Dr,Mail Stop 301-175C, Pasadena, CA 91109 USA. NR 19 TC 15 Z9 15 U1 0 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD MAR-APR PY 2007 VL 44 IS 2 BP 399 EP 411 DI 10.2514/1.21613 PG 13 WC Engineering, Aerospace SC Engineering GA 155WW UT WOS:000245610300012 ER PT J AU Moss, JN Glass, CE Hollis, BR Van Norman, JW AF Moss, James N. Glass, Christopher E. Hollis, Brian R. Van Norman, John W. TI Erratum on low-density aerodynamics for the inflatable reentry vehicle experiment (vol 43, pg 1191, 2006) SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Correction ID FLIGHT MEASUREMENTS; SIMULATION; FLOWS AB The supersonic transitional flow aerodynamics of the inflatable reentry vehicle experiment are simulated with the direct simulation Monte Carlo method. Also, results from Navier-Stokes calculations are presented that provide both a check on the direct simulation Monte Carlo results near continuum conditions and the general trend of the aerodynamic data at lower altitude conditions. Calculations of axial, normal, and static pitching, coefficients are obtained for an angle-of-attack range of 0 to 180 deg. These results clearly demonstrate the strong sensitivity of the aerodynamic coefficients to the relatively low speeds encountered as the inflatable reentry vehicle experiment reenters the atmosphere, and that existing hypersonic aerodynamic data bases for similar geometric configurations are not appropriate for the inflatable reentry vehicle experiment environment. The current numerical simulations focus on the rigid body aerodynamics from 150 to 91 km altitude for the 0 to 180 deg angle of incidence sweep and to lower altitudes (46 km) while at zero incidence. C1 NASA, Langley Res Ctr, Aerothermodynam Branch, Hampton, VA 23681 USA. Analyt Mech Associates Inc, Syst Engn Branch, Hampton, VA 23666 USA. RP Moss, JN (reprint author), NASA, Langley Res Ctr, Aerothermodynam Branch, Mail Stop 408A, Hampton, VA 23681 USA. NR 20 TC 0 Z9 0 U1 0 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD MAR-APR PY 2007 VL 44 IS 2 BP 485 EP 495 DI 10.2514/1.30728 PG 11 WC Engineering, Aerospace SC Engineering GA 155WW UT WOS:000245610300022 ER PT J AU Gaffney, RL AF Gaffney, Richard L., Jr. TI Erratum on design of a pulse-facility nozzle using the rotational method of characteristics (vol 43, pg 1216, 2006) SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Correction AB A new nozzle has been designed for NASA's HYPULSE shock/ expansion tube facility to be used for scramjet engine testing at a Mach 15 flight-enthalpy condition. The nozzle has an area ratio of 9.5:1 that expands the inflow from Mach 6 along the centerline to Mach 8.7 and achieves the goal of increasing the area of the core flow (by a factor of 9). The nozzle contour was generated by a new computer program that solves the Euler equations using the rotational method of characteristics. The rotational method was required to properly include the effects of the boundary layer-induced nonuniformities of the flow properties at the nozzle inflow. Although the density and Mach number vary radially at the nozzle exit due to the nominiformities of the inflow, the new nozzle produces exit flow that is parallel and has uniform static pressure. The design has been verified with a computational fluid dynamics calculation that compares favorably with the method of characteristics solution. C1 NASA, Langley Res Ctr, Hyperson Air Breathing Prop Branch, Hampton, VA 23681 USA. RP Gaffney, RL (reprint author), NASA, Langley Res Ctr, Hyperson Air Breathing Prop Branch, Hampton, VA 23681 USA. EM Richard.L.Gaffney@NASA.GOV NR 12 TC 2 Z9 2 U1 1 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD MAR-APR PY 2007 VL 44 IS 2 BP 496 EP 504 DI 10.2514/1.30729 PG 9 WC Engineering, Aerospace SC Engineering GA 155WW UT WOS:000245610300023 ER PT J AU Yuen, MML Nachtigall, PE Breese, M Vlachos, SA AF Yuen, Michelle M. L. Nachtigall, Paul E. Breese, Marlee Vlachos, Stephanie A. TI The perception of complex tones by a false killer whale (Pseudorca crassidens) SO JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA LA English DT Article ID BOTTLE-NOSED DOLPHINS; HAWAIIAN SPINNER DOLPHINS; TURSIOPS-TRUNCATUS; SIGNATURE WHISTLES; ECHOLOCATION; DIRECTIONALITY; VOCALIZATIONS; MOVEMENT; CALLS; CUE AB Complex tonal whistles are frequently produced by some odontocete species. However, no experimental evidence exists. regarding the detection of complex tones or the discrimination of harmonic frequencies by a marine mammal. The objectives of this investigation were to examine the ability of a false killer whale to discriminate pure tones from complex tones and to determine the minimum intensity level of a harmonic tone required for the whale to make the discrimination. The study was conducted with a. go/no-go modified staircase procedure. The different stimuli were complex tones with a fundamental frequency of 5 kHz with one to five harmonic frequencies. The results from this complex tone discrimination task demonstrated: (1) that the false killer whale was able to discriminate a 5 kHz pure tone from a complex tone with up to five harmonics, and (2) that discrimination thresholds or minimum intensity levels exist for each harmonic combination measured. These results indicate that both frequency level and harmonic content may have contributed to the false killer whale's discrimination of complex tones. (c) 2007 Acoustical Society of America. C1 Univ Hawaii, Hawaii Inst Marine Biol, Kailua, HI 96734 USA. RP Yuen, MML (reprint author), Natl Marine Fisheries Serv, Pacific Isl Reg Off, Suite 1110, Honolulu, HI 96814 USA. EM myuen@hawaii.edu NR 34 TC 5 Z9 5 U1 1 U2 4 PU ACOUSTICAL SOC AMER AMER INST PHYSICS PI MELVILLE PA STE 1 NO 1, 2 HUNTINGTON QUADRANGLE, MELVILLE, NY 11747-4502 USA SN 0001-4966 J9 J ACOUST SOC AM JI J. Acoust. Soc. Am. PD MAR PY 2007 VL 121 IS 3 BP 1768 EP 1774 DI 10.1121/1.2436640 PG 7 WC Acoustics; Audiology & Speech-Language Pathology SC Acoustics; Audiology & Speech-Language Pathology GA 147VT UT WOS:000245031600052 PM 17407913 ER PT J AU Ray, CS Zhang, T Reis, ST Brow, RK AF Ray, C. S. Zhang, T. Reis, S. T. Brow, R. K. TI Determining kinetic parameters for isothermal crystallization of glasses SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Article; Proceedings Paper CT 8th International Symposium on Crystallization in Glasses and Liquids CY SEP 24-28, 2006 CL Jackson Hole, WY ID DIFFERENTIAL THERMAL-ANALYSIS; LITHIUM DISILICATE GLASS; NONISOTHERMAL CRYSTALLIZATION; CRYSTAL NUCLEATION; SILICATE-GLASSES; FORMING LIQUIDS; PHASE-CHANGE; GROWTH; DTA; SURFACE AB Non-isothermal crystallization techniques are frequently used to determine the kinetic parameters for crystallization in glasses. The techniques are experimentally simple and quick, compared with isothermal techniques. However, the analytical models used for non-isothermal data analysis, that were derived from models originally developed for describing isothermal transformation kinetics, are fundamentally flawed. The present paper describes a technique for determining the kinetic parameters for isothermal crystallization in glasses, which eliminates most of the common problems that generally make the study of isothermal crystallization laborious and time consuming. In this technique, the volume fraction of a glass that is crystallized as a function of time during an isothermal hold was determined in a separate experiment using differential thermal analysis. The activation energy (345 +/- 10 kJ/mole) and Avrami parameter (0.89 +/- 0.09) for crystallization of Li2O.2SiO(2) glass determined by the present technique are consistent with the similar values reported in the literature. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. Univ Missouri, Dept Mat Sci & Engn, Rolla, MO 65409 USA. RP Ray, CS (reprint author), NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. EM Chandra.S.Ray@nasa.gov RI zhang, teng/H-5008-2011 NR 40 TC 19 Z9 19 U1 0 U2 16 PU BLACKWELL PUBLISHING PI OXFORD PA 9600 GARSINGTON RD, OXFORD OX4 2DQ, OXON, ENGLAND SN 0002-7820 J9 J AM CERAM SOC JI J. Am. Ceram. Soc. PD MAR PY 2007 VL 90 IS 3 BP 769 EP 773 DI 10.1111/j.1551-2916.2006.01478.x PG 5 WC Materials Science, Ceramics SC Materials Science GA 143KM UT WOS:000244720100016 ER PT J AU Luo, YL Xu, KM Wielicki, BA Wong, T Eitzen, ZA AF Luo, Yali Xu, Kuan-Man Wielicki, Bruce A. Wong, Takmeng Eitzen, Zachary A. TI Statistical analyses of satellite cloud object data from CERES. Part III: Comparison with cloud-resolving model simulations of tropical convective clouds SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID ICE-PHASE MICROPHYSICS; TO-CUMULUS TRANSITION; MARINE BOUNDARY-LAYER; ENERGY SYSTEM CERES; 1998 EL-NINO; RADIATIVE PROPERTIES; ATMOSPHERIC RADIATION; NUMERICAL-SIMULATION; CIRRUS CLOUDS; ACCURATE PARAMETERIZATION AB The present study evaluates the ability of a cloud-resolving model (CRM) to simulate the physical properties of tropical deep convective cloud objects identified from a Clouds and the Earth's Radiant Energy System (CERES) data product. The emphasis of this study is the comparisons among the small-, medium-, and large-size categories of cloud objects observed during March 1998 and between the large-size categories of cloud objects observed during March 1998 (strong El Nino) and March 2000 (weak La Nina). Results from the CRM simulations are analyzed in a way that is consistent with the CERES retrieval algorithm and they are averaged to match the scale of the CERES satellite footprints. Cloud physical properties are analyzed in terms of their summary histograms for each category. It is found that there is a general agreement in the overall shapes of all cloud physical properties between the simulated and observed distributions. Each cloud physical property produced by the CRM also exhibits different degrees of disagreement with observations over different ranges of the property. The simulated cloud tops are generally too high and cloud-top temperatures are too low except for the large-size category of March 1998. The probability densities of the simulated top-of-the-atmosphere (TOA) albedos for all four categories are underestimated for high albedos, while those of cloud optical depth are overestimated at its lowest bin. These disagreements are mainly related to uncertainties in the cloud microphysics parameterization and inputs such as cloud ice effective size to the radiation calculation. Summary histograms of cloud optical depth and TOA albedo from the CRM simulations of the large-size category of cloud objects do not differ significantly between the March 1998 and 2000 periods, consistent with the CERES observations. However, the CRM is unable to reproduce the significant differences in the observed cloud-top height while it overestimates the differences in the observed outgoing longwave radiation and cloud-top temperature between the two periods. Comparisons between the CRM results and the observations for most parameters in March 1998 consistently show that both the simulations and observations have larger differences between the large-and small-size categories than between the large- and medium-size, or between the medium- and small-size categories. However, the simulated cloud properties do not change as much with size as observed. These disagreements are likely related to the spatial averaging of the forcing data and the mismatch in time and space between the numerical weather prediction model from which the forcing data are produced and the CERES observed cloud systems. C1 Natl Inst Aerosp, Hampton, VA 23666 USA. NASA, Langley Res Ctr, Hampton, VA 23665 USA. Sci Applicat Int Corp, Hampton, VA USA. RP Luo, YL (reprint author), Natl Inst Aerosp, 100 Explorat Way, Hampton, VA 23666 USA. EM yali@nianet.org RI Xu, Kuan-Man/B-7557-2013 OI Xu, Kuan-Man/0000-0001-7851-2629 NR 52 TC 13 Z9 13 U1 0 U2 5 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PD MAR PY 2007 VL 64 IS 3 BP 762 EP 785 DI 10.1175/JAS3871.1 PG 24 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 150NB UT WOS:000245222400005 ER PT J AU Weaver, C da Silva, A Chin, M Ginoux, P Dubovik, O Flittner, D Zia, A Remer, L Holben, B Gregg, W AF Weaver, Clark da Silva, Arlindo Chin, Mian Ginoux, Paul Dubovik, Oleg Flittner, Dave Zia, Aahmad Remer, Lorraine Holben, Brent Gregg, Watson TI Direct insertion of MODIS radiances in a global aerosol transport model SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID OPTICAL-PROPERTIES; GOCART MODEL; ASSIMILATION; RETRIEVALS; SATELLITE; ALGORITHM; THICKNESS; BRAZIL; SMOKE; SUN AB In this paper results are presented from a simple offline assimilation system that uses radiances from the Moderate Resolution Imaging Spectroradiometer (MODIS) channels that sense atmospheric aerosols over land and ocean. The MODIS information is directly inserted into the Goddard Chemistry and Aerosol Radiation Transport model (GOCART), which simulates the following five aerosol types: dust, sea salt, black carbon, organic carbon, and sulfate. The goal is to produce three-dimensional fields of these aerosol types for radiative forcing calculations. Products from this assimilation system are compared with ground-based measurements of aerosol optical depth (AOD) from the Aerosol Robotic Network (AERONET). Insertion of MODIS radiances draws the GOCART model closer to the AERONET AOD. However, there are still uncertainties with surface reflectivity over moderately bright surfaces and with the amount of absorbing aerosol. Also described is the assimilation cycle. The forward model takes the aerosol information from the GOCART model and calculates radiances based on optical parameters of the aerosol type, satellite viewing angle, and the particle growth from relative humidity. Because the GOCART model is driven by previously assimilated meteorology, these forward model radiances can be directly compared with the observed MODIS level-2 radiances. The offline assimilation system simply adjusts the aerosol loading in the GOCART model so that the observed minus forward model radiances agree. Minimal change is made to the GOCART aerosol vertical distribution, size distribution, and the ratio of the five different aerosol types. The loading in the GOCART model is updated with new MODIS observations every 6 h. Since the previously assimilated meteorology provides surface wind speed, radiance sensitivity to wind speed over rough ocean is taken into account. Over land the dark target approach, also used by the MODIS-atmosphere group retrieval, is used. If the underlying land surface is deemed dark enough, the surface reflectances at the 0.47- and 0.66-mu m wavelengths are constant multiples of the observed 2.13-mu m reflectance. Over ocean the assimilation AOD compares well with AERONET, over land less so. The results herein are also compared with AERONET-retrieved single-scattering albedo. This research is part of an ongoing effort at NASA Goddard to integrate aerosols into the Goddard Modeling and Assimilation Office (GMAO) products. C1 Global Modeling & Assimilat Off, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Maryland Baltimore Cty, Goddard Sci & Technol Ctr, Baltimore, MD 21228 USA. NASA, Goddard Space Flight Ctr, Atmospher Chem & Dynam Branch, Greenbelt, MD 20771 USA. NOAA, Geophys Fluid Dynam Lab, Princeton, NJ USA. NASA, Goddard Space Flight Ctr, Biospher Sci Branch, Greenbelt, MD 20771 USA. NASA, Langley Res Ctr, Climate Sci Branch, Langley, VA USA. NASA, Goddard Space Flight Ctr, Climate & Radiat Branch, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Oceans & Ice Branch, Greenbelt, MD 20771 USA. RP Weaver, C (reprint author), Global Modeling & Assimilat Off, Goddard Space Flight Ctr, Code 613-3, Greenbelt, MD 20771 USA. EM weaver@blueberry.gsfc.nasa.gov RI Dubovik, Oleg/A-8235-2009; da Silva, Arlindo/D-6301-2012; Ginoux, Paul/C-2326-2008; Chin, Mian/J-8354-2012 OI Dubovik, Oleg/0000-0003-3482-6460; da Silva, Arlindo/0000-0002-3381-4030; Ginoux, Paul/0000-0003-3642-2988; NR 31 TC 14 Z9 14 U1 1 U2 5 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-4928 EI 1520-0469 J9 J ATMOS SCI JI J. Atmos. Sci. PD MAR PY 2007 VL 64 IS 3 BP 808 EP 826 DI 10.1175/JAS3838.1 PG 19 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 150NB UT WOS:000245222400007 ER PT J AU Johnson, DE Tao, WK Simpson, J AF Johnson, D. E. Tao, W. -K. Simpson, J. TI A study of the response of deep tropical clouds to large-scale thermodynamic forcings. Part II: Sensitivities to microphysics, radiation, and surface fluxes SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID RESOLVING MODEL SIMULATIONS; COARE CONVECTIVE SYSTEMS; LONG-TERM BEHAVIOR; TOGA-COARE; SQUALL LINE; PHASE-III; CUMULUS ENSEMBLES; ICE MICROPHYSICS; SOLAR-RADIATION; GATE AB The Goddard Cumulus Ensemble (GCE) model is used to examine the sensitivities of multiday 2D simulations of deep tropical convection to surface fluxes, interactive radiation, and ice microphysical processes. The simulations incorporate large-scale temperature, moisture, and momentum forcings, from the Tropical Ocean Global Atmosphere Coupled Ocean-Atmosphere Response Experiment (TOGA COARE) for the period 19-27 December 1992. This study shows that, when surface fluxes are eliminated, the mean simulated atmosphere is much cooler and drier, convection and CAPE are much weaker, precipitation is less, and low-level to midlevel cloudiness is much greater. Surface fluxes using the TOGA COARE flux algorithm are weaker than with the aerodynamic formulation, but closer to the observed fluxes. In addition, trends similar to those noted above for the case without surface fluxes are produced for the TOGA COARE flux case, albeit to a much lesser extent. The elimination of shortwave and longwave radiation is found to have only minimal effects on the mean thermodynamics, convection, and precipitation. However, exclusion of radiation in the model does have a significant impact on cloud temperatures and structure above 200 mb. The removal of ice microphysical processes produces major changes in the structure of the clouds. Much of the liquid water is transported to the upper levels of the troposphere and evaporates, resulting in less mean total surface precipitation. The precipitation primarily occurs in regions of narrow, but intense, convective rainfall bands. The elimination of melting processes (diabatic cooling and conversions to rain) leads to greater (ice) hydrometeor mass below the 0 degrees C level and reduced latent cooling. This, along with weaker vertical cloud mass fluxes, produces a much warmer and moister boundary layer, and a greater mean CAPE. Finally, the elimination of the graupel species has only a small impact on mean total precipitation, thermodynamics, and dynamics of the simulation, but does produce much greater snow mass just above the melting layer. C1 NOAA, NWS, NCEP, EMC,WWB, Camp Springs, MD 20746 USA. NCEP, Environm Modeling Ctr, Camp Springs, MD USA. Sci Applicat Int Corp, Gen Sci Operat, Beltsville, MD USA. NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. RP Johnson, DE (reprint author), NOAA, NWS, NCEP, EMC,WWB, 206,5200 Auth Rd, Camp Springs, MD 20746 USA. EM dan.e.johnson@noaa.gov NR 46 TC 13 Z9 13 U1 0 U2 2 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-4928 EI 1520-0469 J9 J ATMOS SCI JI J. Atmos. Sci. PD MAR PY 2007 VL 64 IS 3 BP 869 EP 886 DI 10.1175/JAS3846.1 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 150NB UT WOS:000245222400010 ER PT J AU Zhou, DK Smith, WL Liu, X Larar, AM Mango, SA Huang, HL AF Zhou, Daniel K. Smith, William L., Sr. Liu, Xu Larar, Allen M. Mango, Stephen A. Huang, Hung-Lung TI Physically retrieving cloud and thermodynamic parameters from ultraspectral IR measurements SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID NAST-I; TIROS-N; TEMPERATURE; ALGORITHM; INVERSION; METHODOLOGY; VALIDATION; RADIATION; MOISTURE; CIRRUS AB A physical inversion scheme has been developed dealing with cloudy as well as cloud-free radiance observed with ultraspectral infrared sounders to simultaneously retrieve surface, atmospheric thermodynamic, and cloud microphysical parameters. A fast radiative transfer model, which applies to the clouded atmosphere, is used for atmospheric profile and cloud parameter retrieval. A one-dimensional (1D) variational multivariable inversion solution is used to improve an iterative background state defined by an eigenvector-regression retrieval. The solution is iterated in order to account for nonlinearity in the 1D variational solution. It is shown that relatively accurate temperature and moisture retrievals can be achieved below optically thin clouds. For optically thick clouds, accurate temperature and moisture profiles down to cloud-top level are obtained. For both optically thin and thick cloud situations, the cloud-top height can be retrieved with relatively high accuracy (i.e., error < 1 km). National Polar-orbiting Operational Environmental Satellite System (NPOESS) Airborne Sounder Testbed Interferometer (NAST-I) retrievals from the The Observing-System Research and Predictability Experiment (THORPEX) Atlantic Regional Campaign are compared with coincident observations obtained from dropsondes and the nadir-pointing cloud physics lidar (CPL). This work was motivated by the need to obtain solutions for atmospheric soundings from infrared radiances observed for every individual field of view, regardless of cloud cover, from future ultraspectral geostationary satellite sounding instruments, such as the Geosynchronous Imaging Fourier Transform Spectrometer (GIFTS). However, this retrieval approach can also be applied to the ultraspectral sounding instruments to fly on polar satellites, such as the Infrared Atmospheric Sounding Interferometer (IASI) on the European MetOp satellite, the Cross-track Infrared Sounder (CrIS) on the NPOESS Preparatory Project, and the follow-on NPOESS series of satellites. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. Hampton Univ, Hampton, VA 23668 USA. Univ Wisconsin, Madison, WI 53706 USA. NPOESS, Integrated Program Off, Silver Spring, MD USA. RP Zhou, DK (reprint author), NASA, Langley Res Ctr, Mail Stop 401A, Hampton, VA 23681 USA. EM daniel.k.zhou@nasa.gov RI Richards, Amber/K-8203-2015 NR 33 TC 35 Z9 36 U1 1 U2 7 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PD MAR PY 2007 VL 64 IS 3 BP 969 EP 982 DI 10.1175/JAS3877.1 PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 150NB UT WOS:000245222400016 ER PT J AU Conway, EM AF Conway, Erik M. TI Plows, plagues & petroleum: How humans took control of climate SO JOURNAL OF THE HISTORY OF BIOLOGY LA English DT Book Review C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Conway, EM (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 1 TC 1 Z9 1 U1 2 U2 2 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0022-5010 EI 1573-0387 J9 J HIST BIOL JI J. Hist. Biol. PD MAR PY 2007 VL 40 IS 1 BP 199 EP 201 PG 3 WC Biology; History & Philosophy Of Science SC Life Sciences & Biomedicine - Other Topics; History & Philosophy of Science GA 137SX UT WOS:000244313600013 ER PT J AU Malkova, N Ning, CZ AF Malkova, N. Ning, C. Z. TI Existence and control of Shockley surface states of a one-dimensional defect chain in a photonic crystal SO JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS LA English DT Article ID WAVES; MEDIA AB We present detailed results of analytical and numerical investigation of the Shockley surface states in photonic crystals doped with a chain of alternating s- and p-type defects. Conditions for the existence and control of such surface states are studied using the empirical tight-binding model and verified by the finite-difference time-domain technique. We show for the first time, to our knowledge, that, in contrast to the case of solids, the Shockley states in photonic crystals with complete unit cells of defects do not appear simultaneously with the opening of the inverted bandgap between s and p bands. Rather, the width of the inverted bandgap must reach a critical value equal to the separation between the discrete levels. This results in a system size effect of the Shockley states in photonic crystals. We show how such system size effect can be used to control the surface states. We also demonstrate the control of the Shockley states by controlling the overlap of s and p bands, achieved through change in either the radius of one of the defects or the refractive index via electro-optical effects. (c) 2007 Optical Society of America. C1 NASA, Ames Res Ctr, Ctr Nanotechnol, Moffett Field, CA 94035 USA. Arizona State Univ, Dept Elect Engn, Tempe, AZ 85287 USA. RP Malkova, N (reprint author), NASA, Ames Res Ctr, Ctr Nanotechnol, Moffett Field, CA 94035 USA. EM nmalkova@mail.arc.nasa.gov RI Ning, C. Z./D-4699-2009 OI Ning, C. Z./0000-0003-4583-8889 NR 19 TC 2 Z9 2 U1 0 U2 5 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 0740-3224 J9 J OPT SOC AM B JI J. Opt. Soc. Am. B-Opt. Phys. PD MAR PY 2007 VL 24 IS 3 BP 707 EP 715 DI 10.1364/JOSAB.24.000707 PG 9 WC Optics SC Optics GA 141OI UT WOS:000244587900040 ER PT J AU Kolasinski, RD Polk, JE Goebel, D Johnson, LK AF Kolasinski, Robert D. Polk, James E. Goebel, Dan Johnson, Lee K. TI Sputtering yield measurements at glancing incidence using a quartz crystal microbalance SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A LA English DT Article ID ION-BOMBARDMENT; RESONATORS; DEPENDENCE; ENERGIES; METALS; ANGLE AB Low energy sputtering yields at grazing incidence have been investigated experimentally using a quartz crystal microbalance (QCM) technique. This method involved precoating the QCM with a thin film of the desired target material and relating the resonance frequency shift directly to mass loss during ion bombardment. A highly focused, low divergence ion beam provided a well defined incidence angle. Focusing most of the ion current on the center of the target allowed for higher sensitivity by taking into account the radial mass sensitivity of the QCM. Measurements of Mo, Cu, and W sputtering yields were taken for low energy (80-1000 eV) Xe+ and Ar+ to validate this experimental method. The target films ranged from 3.5 to 8.0 mu m in thickness and were deposited so that their crystal structure and density would. match those of the bulk material as closely as possible. These properties were characterized using a combination of scanning electron microscope imagery, profilometry, and x-ray diffraction. At normal incidence, the sputtering yields demonstrated satisfactory agreement with previously published work. At angles of incidence up to 40 degrees off normal, the data agreed well with predictions from existing theoretical models. Sputtering yields were found to increase by a factor of 1.6 over this range. The optimum angle for sputtering occurred at 55 degrees, after which the yields rapidly decreased. Measurements were taken up to 80 degrees from the surface normal. (c) 2007 American Vacuum Society. C1 CALTECH, Dept Mech Engn, Pasadena, CA 91125 USA. CALTECH, Jet Prop Lab, NASA, Prop & Mat Engn Sect, Pasadena, CA 91109 USA. RP Kolasinski, RD (reprint author), Sandia Natl Labs, POB 969,MS 916, Livermore, CA 94551 USA. EM rkolasi@sandia.gov NR 34 TC 9 Z9 9 U1 1 U2 10 PU A V S AMER INST PHYSICS PI MELVILLE PA STE 1 NO 1, 2 HUNTINGTON QUADRANGLE, MELVILLE, NY 11747-4502 USA SN 0734-2101 EI 1520-8559 J9 J VAC SCI TECHNOL A JI J. Vac. Sci. Technol. A PD MAR-APR PY 2007 VL 25 IS 2 BP 236 EP 245 DI 10.1116/1.2435375 PG 10 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA 149TI UT WOS:000245169200008 ER PT J AU Sun, XH Calebotta, G Yu, B Selvaduray, G Meyyappan, M AF Sun, Xuhui Calebotta, Gabe Yu, Bin Selvaduray, Guna Meyyappan, M. TI Synthesis of germanium nanowires on insulator catalyzed by indium or antimony SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B LA English DT Article ID CHEMICAL-VAPOR-DEPOSITION; FIELD-EFFECT TRANSISTORS; LIQUID-SOLID MECHANISM; GE NANOWIRES; GROWTH; GOLD; SI; NANOCRYSTALS; TRANSPORT AB Chemically synthesized one dimensional germanium nanowires on insulator offer a viable nanomaterial platform for high-performance and low-power electronics. The use, of noncontaminating metal catalysts and growth of nanowires on an insulator layer facilitate the direct integration of nanowire components into future nanoelectronic chips. Indium and antimony were used as catalysts for germanium nanowire growth in a simple thermal evaporation process. The self-assembly of germanium nanowire on insulator follows the vapor-liquid-solid process. Results show that the nanowires, 10-20 nm in diameter and tens of microns in length are single crystals with a diamond cubic lattice structure and grow preferentially along the (111) crystallographic direction. (c) 2007American Vacuum Society. C1 NASA, Ames Res Ctr, Ctr Nanotechnol, Moffett Field, CA 94035 USA. San Jose State Univ, Dept Chem & Mat Engn, San Jose, CA 95192 USA. RP Sun, XH (reprint author), NASA, Ames Res Ctr, Ctr Nanotechnol, Moffett Field, CA 94035 USA. EM xsun@arc.nasa.gov; byu@mail.arc.nasa.gov RI Sun, Xuhui /K-5689-2012 NR 22 TC 31 Z9 31 U1 0 U2 8 PU A V S AMER INST PHYSICS PI MELVILLE PA STE 1 NO 1, 2 HUNTINGTON QUADRANGLE, MELVILLE, NY 11747-4502 USA SN 1071-1023 J9 J VAC SCI TECHNOL B JI J. Vac. Sci. Technol. B PD MAR-APR PY 2007 VL 25 IS 2 BP 415 EP 420 DI 10.1116/1.2713407 PG 6 WC Engineering, Electrical & Electronic; Nanoscience & Nanotechnology; Physics, Applied SC Engineering; Science & Technology - Other Topics; Physics GA 161VT UT WOS:000246045300021 ER PT J AU Bluth, GJS Shannon, JM Watson, IM Prata, AJ Realmuto, VJ AF Bluth, G. J. S. Shannon, J. M. Watson, I. M. Prata, A. J. Realmuto, V. J. TI Development of an ultra-violet digital camera for volcanic SO(2) imaging SO JOURNAL OF VOLCANOLOGY AND GEOTHERMAL RESEARCH LA English DT Article DE volcano monitoring; ultraviolet camera; degassing; sulfur dioxide ID SOUFRIERE HILLS VOLCANO; EMISSIONS; GAS; ATMOSPHERE AB In an effort to improve monitoring of passive volcano degassing, we have constructed and tested a digital camera for quantifying the sulfur dioxide (SO(2)) content of volcanic plumes. The camera utilizes a bandpass filter to collect photons in the ultra-violet (UV) region where SO(2) selectively absorbs LTV light-SO(2) is quantified by imaging calibration cells of known SO(2) concentrations. Images of volcanic SO(2) plumes were collected at four active volcanoes with persistent passive degassing: Villarrica, located in Chile, and Santiaguito, Fuego, and Pacaya, located in Guatemala. Images were collected from distances ranging between 4 and 28 kin away, with acceptable detection up to approximately 16 km. Camera set-up time in the field ranges from 5-10 min and temporal resolution of up to 6 images per minute is possible, which combined with the camera's field of view makes a continuous SO(2) dataset attainable. Variable in-plume concentrations can be observed and accurate plume speeds (or rise rates) can readily be determined by tracing individual portions of the plume within sequential images. Initial fluxes computed from camera images require a correction for the effects of environmental light scattered into the field of view. At Fuego volcano, simultaneous measurements of corrected SO(2) fluxes with the camera and a Correlation Spectrometer (COSPEC) agreed within 25%. Experiments at the other sites were equally encouraging, and demonstrated the camera's ability to detect SO(2) under variable background meteorological and environmental conditions. This early work has shown great success in imaging SO(2) plumes and offers promise for volcano monitoring due to its rapid deployment and data processing capabilities, relatively low cost, and improved interpretation afforded by synoptic coverage from a range of distances. (c) 2006 Elsevier B.V. All rights reserved. C1 Michigan Technol Univ, Dept Geol Engn & Sci, Houghton, MI 49931 USA. Finlandia Univ, Hancock, MI 49930 USA. Univ Bristol, Dept Earth Sci, Bristol BS8 IRJ, Avon, England. Norwegian Inst Air Res, N-2027 Kjeller, Norway. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Bluth, GJS (reprint author), Michigan Technol Univ, Dept Geol Engn & Sci, Houghton, MI 49931 USA. EM gbluth@mtu.edu RI Watson, Matt/E-5236-2011 OI Watson, Matt/0000-0001-9198-2203 NR 32 TC 67 Z9 67 U1 0 U2 11 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0377-0273 J9 J VOLCANOL GEOTH RES JI J. Volcanol. Geotherm. Res. PD MAR 1 PY 2007 VL 161 IS 1-2 BP 47 EP 56 DI 10.1016/j.jvolgeores.2006.11.004 PG 10 WC Geosciences, Multidisciplinary SC Geology GA 147QW UT WOS:000245018500004 ER PT J AU Siddiqi, AM Li, H Williams, W Faruque, F Lai, K Baliga, M Flowers, R Beach, J AF Siddiqi, A. M. Li, H. Williams, W. Faruque, F. Lai, K. Baliga, M. Flowers, R. Beach, J. TI Use of hyperspectral imaging in detection of precancerous cells SO LABORATORY INVESTIGATION LA English DT Meeting Abstract CT 96th Annual Meeting of the United-States-and-Canadian-Academy-of-Pathology CY MAR 24-30, 2007 CL San Diego, CA SP US & Canadian Acad Pathol C1 Univ Mississippi, Jackson, MS 39216 USA. Univ Miami, Miami, FL 33152 USA. NASA, Stennis Space Ctr, MS USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU NATURE PUBLISHING GROUP PI NEW YORK PA 75 VARICK STREET, 9TH FLOOR, NEW YORK, NY 10013-1917 USA SN 0023-6837 J9 LAB INVEST JI Lab. Invest. PD MAR PY 2007 VL 87 SU 1 MA 365 BP 84A EP 84A PG 1 WC Medicine, Research & Experimental; Pathology SC Research & Experimental Medicine; Pathology GA 146LG UT WOS:000244935300366 ER PT J AU Hole, F Zaitchik, BF AF Hole, F. Zaitchik, B. F. TI Policies, plans, practice, and prospects: Irrigation in northeastern Syria SO LAND DEGRADATION & DEVELOPMENT LA English DT Article DE land-use land cover change; irrigation agriculture; remote sensing; historical drivers; sustainability; semi-arid steppe; Near East; Syria AB Over the past half-century the agricultural landscape of northeastern Syria has been transformed, due in large part to the introduction of significant irrigation to the steppe. At the beginning of this period, irrigation was confined almost entirely to river floodplains and natural depressions. The steppe was dominated by wintertime rain-fed agriculture and year-round grazing. The introduction of diesel-powered wells and, subsequently, state-operated dam and canal systems, has led to the expansion of both wintertime and summertime irrigation on the steppe away from the floodplain. The sustainability of these irrigation projects has always been suspect. Even as technologies for water extraction have allowed for previously impossible patterns of cultivation, the combination of declining water quality, a deepening water-table, and degradation-prone soils have limited crop yields and led to the rapid abandonment of many steppe farms. The actual trajectory of land-use in the region is determined by social and political forces as well as by hydrology and surficial geology. In this paper we examine recent land-use history in the watersheds of two tributaries of the Euphrates River, the Balikh and Khabur. A review of historical drivers of development in the region is combined with satellite analyses to provide an overview of the structure and dynamics of land-use in this water-limited region. Copyright (0 2006 John Wiley & Sons, Ltd. C1 Yale Univ, Dept Anthropol, New Haven, CT 06520 USA. NASA Goddard Space Flight Ctr, UMCP ESSIC Res Assoc, Hydrol Sci Branch, Greenbelt, MD 20771 USA. RP Hole, F (reprint author), Yale Univ, Dept Anthropol, Box 8277, New Haven, CT 06520 USA. EM frank.hole@yale.edu RI Zaitchik, Benjamin/B-9461-2013 NR 35 TC 1 Z9 1 U1 1 U2 15 PU JOHN WILEY & SONS LTD PI CHICHESTER PA THE ATRIUM, SOUTHERN GATE, CHICHESTER PO19 8SQ, W SUSSEX, ENGLAND SN 1085-3278 J9 LAND DEGRAD DEV JI Land Degrad. Dev. PD MAR-APR PY 2007 VL 18 IS 2 BP 133 EP 152 DI 10.1002/ldr.772 PG 20 WC Environmental Sciences; Soil Science SC Environmental Sciences & Ecology; Agriculture GA 156XB UT WOS:000245682100002 ER PT J AU Jenerette, GD Harlan, SL Brazel, A Jones, N Larsen, L Stefanov, WL AF Jenerette, G. Darrel Harlan, Sharon L. Brazel, Anthony Jones, Nancy Larsen, Larissa Stefanov, William L. TI Regional relationships between surface temperature, vegetation, and human settlement in a rapidly urbanizing ecosystem SO LANDSCAPE ECOLOGY LA English DT Article DE phoenix; urbanization; urban heat island; vegetation; path analysis; remote sensing; census; income; population density ID HEAT-ISLAND; LAND-USE; ECOLOGICAL-SYSTEMS; LANDSCAPE; CITIES; COVER; SCALE; CITY; URBANIZATION; MICROCLIMATE AB Regional climate change induced by rapid urbanization is responsible for and may result from changes in coupled human-ecological systems. Specifically, the distribution of urban vegetation may be an important intermediary between patterns of human settlement and regional climate spatial variability. To test this hypothesis we identified the relationships between surface temperature, one component of regional climate, vegetation, and human settlement patterns in the Phoenix, AZ, USA region. Combining satellite-derived surface temperature and vegetation data from an early summer day with US Census and topographic data, we found substantial surface temperature differences within the city that correlate primarily with an index of vegetation cover. Furthermore, both of these patterns vary systematically with the social characteristics of neighborhoods through the region. Overall, every $10,000 increase in neighborhood annual median household income was associated with a 0.28 degrees C decrease in surface temperature on an early summer day in Phoenix. Temperature variation within a neighborhood was negatively related to population density. A multivariate model generated using path analysis supports our hypothesis that social impacts on surface temperature occur primarily through modifications of vegetation cover. Higher income neighborhoods were associated with increased vegetation cover and higher density neighborhoods were associated with decreased vegetation variability. These results suggest that settlement patterns in the central Arizona region influence regional climate through multiple pathways that are heterogeneously distributed throughout the city. C1 Ohio State Univ, Sch Nat Resources, Columbus, OH 43201 USA. Arizona State Univ, Sch Life Sci, Tempe, AZ 85287 USA. Arizona State Univ, Sch Human Evolut & Social Change, Tempe, AZ 85287 USA. Arizona State Univ, Sch Geog Sci, Tempe, AZ 85287 USA. Arizona State Univ, Coll Architecture & Environm Design, Tempe, AZ 85287 USA. Univ Michigan, Taubman Coll Architecture & Urban Planning, Ann Arbor, MI 48109 USA. Lyndon B Johnson Space Ctr, Image Sci & Anal Lab, Houston, TX 77059 USA. Univ Arizona, Ecol & Evolutionary Biol Dept, Tucson, AZ 85721 USA. RP Jenerette, GD (reprint author), Ohio State Univ, Sch Nat Resources, 2021 Coffey Rd, Columbus, OH 43201 USA. EM jenerette@gmail.com NR 74 TC 133 Z9 142 U1 11 U2 90 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0921-2973 J9 LANDSCAPE ECOL JI Landsc. Ecol. PD MAR PY 2007 VL 22 IS 3 BP 353 EP 365 DI 10.1007/s10980-006-9032-z PG 13 WC Ecology; Geography, Physical; Geosciences, Multidisciplinary SC Environmental Sciences & Ecology; Physical Geography; Geology GA 139TJ UT WOS:000244455200003 ER PT J AU Schultz, JK Pyle, RL DeMartini, E Bowen, BW AF Schultz, Jennifer K. Pyle, Richard L. DeMartini, Edward Bowen, Brian W. TI Genetic connectivity among color morphs and Pacific archipelagos for the flame angelfish, Centropyge loriculus SO MARINE BIOLOGY LA English DT Article ID PELAGIC LARVAL DURATION; GREAT-BARRIER-REEF; MITOCHONDRIAL-DNA; POPULATION-GROWTH; SPECIES COMPLEX; FISH LARVAE; PHYLOGEOGRAPHY; POMACANTHIDAE; HYBRIDIZATION; CONSERVATION AB Color variation is used in taxonomic classification of reef fishes, but it may not reliably indicate evolutionary divergence. In the central Pacific, there are three color morphs of the flame angelfish, Centropyge loriculus: a red morph that occurs primarily in the Hawaiian archipelago, the endemic Marquesan color morph with reduced black markings, and an orange morph that occurs throughout the rest of Oceania. The red and orange morphs co-occur at Johnston Atoll (1,300 km south of Hawai'i), but intermediate forms have not been reported. To determine whether the three color morphs represent distinct evolutionary lineages, we compared 641 base pairs of mitochondrial cytochrome b. Forty-one closely related haplotypes were observed in 116 individuals. Analysis of molecular variance (AMOVA) indicated no significant genetic structure among color morphs (Phi(ST) = 0.011, P = 0.147). Likewise, there was no significant pairwise structure between sampling locations, separated by up to 5,700 km, after a Bonferroni correction (Phi(ST) = 0.000-0.080, P = 0.0130-0.999). Genetic studies in conjunction with larval distribution data indicate that Centropyge species are highly dispersive. While there is a strong geographic component to the distribution of color morphs in C. loriculus, we find no evidence for corresponding genetic partitioning. We do not rule out an adaptive role for color differentiation, but our data do not support emerging species. C1 Univ Hawaii, Hawaii Inst Marine Biol, Dept Zool, Kaneohe, HI 96744 USA. Bernice P Bishop Museum, Honolulu, HI 96817 USA. Natl Marine Fisheries Serv, Pacific Isl Fisheries Sci Ctr, Honolulu, HI 96822 USA. RP Schultz, JK (reprint author), Univ Hawaii, Hawaii Inst Marine Biol, Dept Zool, POB 1346, Kaneohe, HI 96744 USA. EM jschultz@hawaii.edu NR 54 TC 32 Z9 34 U1 0 U2 9 PU SPRINGER HEIDELBERG PI HEIDELBERG PA TIERGARTENSTRASSE 17, D-69121 HEIDELBERG, GERMANY SN 0025-3162 EI 1432-1793 J9 MAR BIOL JI Mar. Biol. PD MAR PY 2007 VL 151 IS 1 BP 167 EP 175 DI 10.1007/s00227-006-0471-5 PG 9 WC Marine & Freshwater Biology SC Marine & Freshwater Biology GA 140EA UT WOS:000244485800015 ER PT J AU Chao, Y DiGiacomo, PM AF Chao, Yi DiGiacomo, Paid M. TI Development of an ocean forecasting system off the west coast of the United States: Sea level applications SO MARINE TECHNOLOGY SOCIETY JOURNAL LA English DT Article ID DATA ASSIMILATION; MODEL; CIRCULATION; FORMULATION AB In the context of continuing development and implementation of global and regional ocean observing systems, we describe here the need and essential ingredients for a coastal ocean forecasting system focused on sea level and associated inundation issues and applications. Such a system must consist of the following key components. 1) satellite and in situ observations, 2) atmospheric forcing, 3) ocean circulation and tide modeling, 4) data assimilation for initialization, 5) forecast error estimation, and 6) data and model management. We describe these components, their continuing development and integrated implementation and application as part of a prototype coastal ocean forecast system for the U.S. West Coast. The multi-scale nested modelling by increasing the spatial resolution of observations. This and other regional ocean forecast systems are complementary and necessary elements of the emerging Global Ocean Observing System (GOOS) needed to predict changes in sea level. Building on the increasing maturity of ocean observing and forecasting capabilities, there are a number of significant challenges that require immediate attention, planning and development. These include: 1) further development of models, data assimilation algorithms and information management system, 2) adaptive sampling to reduce uncertainty in ocean forecasting, 3) Observing System Simulation Experiments (OSSE) to optimize observing system design, 4) bridging the land-sea boundary and 5) moving from measurements to information in support of management and decision-making. C1 CALTECH, Earth Remote Sensing Sci Sect, Jet Propuls Lab, Pasadena, CA 91125 USA. NOAA, Ctr Satellite Applicat & Res, Natl Environm Satellite Data & Informat Serv, Silver Spring, MD 20910 USA. RP Chao, Y (reprint author), CALTECH, Earth Remote Sensing Sci Sect, Jet Propuls Lab, Pasadena, CA 91125 USA. RI DiGiacomo, Paul/F-5584-2010 OI DiGiacomo, Paul/0000-0003-4550-1899 NR 26 TC 0 Z9 0 U1 0 U2 0 PU MARINE TECHNOLOGY SOC INC PI COLUMBIA PA 5565 STERRETT PLACE, STE 108, COLUMBIA, MD 21044 USA SN 0025-3324 J9 MAR TECHNOL SOC J JI Mar. Technol. Soc. J. PD SPR PY 2007 VL 41 IS 1 BP 84 EP 93 PG 10 WC Engineering, Ocean; Oceanography SC Engineering; Oceanography GA 174DM UT WOS:000246921400011 ER PT J AU McEwan, MJ Anicich, VG AF McEwan, Murray J. Anicich, Vincent G. TI Titan's ion chemistry: A laboratory perspective SO MASS SPECTROMETRY REVIEWS LA English DT Review DE titan; ionosphere; ion-molecule; chemical processing ID ABSOLUTE CROSS-SECTIONS; DISSOCIATIVE RECOMBINATION; ASSOCIATION REACTIONS; BRANCHING RATIOS; HYDROCARBON IONS; UPPER-ATMOSPHERE; 1 MICRON; IONOSPHERE; VOYAGER-1; MOLECULE AB Some of the most interesting objects in the solar system are those bodies that have significant atmospheres. The discovery that Titan, Saturn's largest satellite, has a substantial nitrogen-based atmosphere makes it a prime extraterrestrial object of interest. The advent of the Cassini orbiter spacecraft program that is able to observe and sample Titan's ionosphere adds greatly to this interest. We report here a summary of some of the efforts that have been made in the laboratory to understand the processes responsible for chemical processing of the primary ions formed in Titan's ionosphere, into the ions observed by in situ sampling. The presence of significant hydrocarbons and the colder temperatures of Titan's ionosphere lead to a much greater complexity in the ion chemistry of Titan than is apparent in the ion chemistry of Earth. A review of all the ion-molecule chemistry investigated in laboratory studies relevant to Titan is included as a table. The complexity of some of the hydrocarbon ion structures formed in just three reactive ion-molecule sequences from the primary ions has required a new experimental methodology which is discussed. (c) 2007 Wiley Periodicals, Inc. C1 Univ Canterbury, Dept Chem, Christchurch 1, New Zealand. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP McEwan, MJ (reprint author), Univ Canterbury, Dept Chem, PB4800, Christchurch 1, New Zealand. EM murray.mcewan@canterbury.ac.nz NR 48 TC 31 Z9 31 U1 2 U2 9 PU JOHN WILEY & SONS INC PI HOBOKEN PA 111 RIVER ST, HOBOKEN, NJ 07030 USA SN 0277-7037 J9 MASS SPECTROM REV JI Mass Spectrom. Rev. PD MAR-APR PY 2007 VL 26 IS 2 BP 281 EP 319 DI 10.1002/mas.20117 PG 39 WC Spectroscopy SC Spectroscopy GA 138GV UT WOS:000244352000008 PM 17216629 ER PT J AU Connolly, HC Zipfel, J Folco, L Smith, C Jones, RH Benedix, G Righter, K Yamaguchi, A Aoudjehane, HC Grossman, JN AF Connolly, Harold C. Zipfel, Jutta Folco, Luigi Smith, Caroline Jones, Rhian H. Benedix, Gretchen Righter, Kevin Yamaguchi, Akira Aoudjehane, Hasnaa Chennaoui Grossman, Jeffrey N. TI The Meteoritical Bulletin, No. 91, 2007 March SO METEORITICS & PLANETARY SCIENCE LA English DT Article C1 Kingsborough Community Coll, Dept Phys Sci, Brooklyn, NY 11235 USA. CUNY, Grad Sch, Brooklyn, NY 11210 USA. Amer Museum Nat Hist, Dept Earth & Planetary Sci, New York, NY 10024 USA. Univ Arizona, Dept Planetary Sci, Lunar & Planetary Lab, Tucson, AZ 85721 USA. Forsch Inst & Nat Museum Senckenberg, Sekt Meteoriten Forsch, D-60325 Frankfurt, Germany. Museo Nazl Antartide, I-53100 Siena, Italy. Nat Hist Museum, Dept Mineral, London SW7 5BD, England. Univ New Mexico, Dept Earth & Planetary Sci, Albuquerque, NM 87131 USA. NASA, Lyndon B Johnson Space Ctr, Code ST, Houston, TX 77058 USA. Natl Inst Polar Res, Antarctic Meteorite Res Ctr, Tokyo 1738515, Japan. Univ Hassan II Casablanca, Fac Sci, Dept Geol, Casablanca, Morocco. US Geol Survey, Reston, VA 20192 USA. RP Connolly, HC (reprint author), Kingsborough Community Coll, Dept Phys Sci, 2001 Oriental Blvd, Brooklyn, NY 11235 USA. EM meteorite@kingsborough.edu NR 0 TC 28 Z9 29 U1 0 U2 2 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 USA SN 1086-9379 J9 METEORIT PLANET SCI JI Meteorit. Planet. Sci. PD MAR PY 2007 VL 42 IS 3 BP 413 EP 466 PG 54 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 150LX UT WOS:000245219400008 ER PT J AU Siddiqi, AM Li, H Williams, W Faruque, F Lai, K Baliga, M Flowers, R Beach, J AF Siddiqi, A. M. Li, H. Williams, W. Faruque, F. Lai, K. Baliga, M. Flowers, R. Beach, J. TI Use of hyperspectral imaging in detection of precancerous cells SO MODERN PATHOLOGY LA English DT Meeting Abstract CT 96th Annual Meeting of the United-States-and-Canadian-Academy-of-Pathology CY MAR 24-30, 2007 CL San Diego, CA SP US & Canadian Acad Pathol C1 Univ Mississippi, Jackson, MS 39216 USA. Univ Miami, Miami, FL 33152 USA. NASA, Stennis Space Ctr, MS USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU NATURE PUBLISHING GROUP PI NEW YORK PA 75 VARICK STREET, 9TH FLOOR, NEW YORK, NY 10013-1917 USA SN 0893-3952 J9 MODERN PATHOL JI Mod. Pathol. PD MAR PY 2007 VL 20 SU 2 MA 365 BP 84A EP 84A PG 1 WC Pathology SC Pathology GA 146GL UT WOS:000244922400366 ER PT J AU Ramirez-Beltran, ND Lau, WKM Winter, A Castro, JM Escalante, NR AF Ramirez-Beltran, Nazarlo D. Lau, William K. M. Winter, Amos Castro, Joan M. Escalante, Nazarlo Ramirez TI Empirical probability models to predict precipitation levels over Puerto Rico stations SO MONTHLY WEATHER REVIEW LA English DT Article ID NORTH-ATLANTIC OSCILLATION; SOUTHERN-OSCILLATION; RAINFALL; TEMPERATURE AB A new algorithm is proposed to predict the level of rainfall (above normal, normal, and below normal) in Puerto Rico that relies on probability and empirical models. The algorithm includes a theoretical probability model in which parameters are expressed as regression equations containing observed meteorological variables. Six rainfall stations were used in this study to implement and assess the reliability of the models. The stations, located throughout Puerto Rico, have monthly records that extend back 101 yr. The maximum likelihood method is used to estimate the parameters of the empirical probability models. A variable selection (VS) algorithm identifies the minimum number of variables that maximize the correlation between predictors and a predictand. The VS algorithm is used to identify the initial point and the maximum likelihood is optimized by using the sequential quadratic programming algorithm. Ten years of cross validation were applied to the results from six stations. The proposed method outperforms both climatology and damped persistence models. Results suggest that the methodology implemented here can be used as a potential toot to predict the level of rainfall at any station located on a tropical island, assuming that at least 50 yr of monthly rainfall observations are available. Model analyses show that meteorological indices can be used to predict rainfall stages. C1 Univ Puerto Rico, Dept Ind Engn, Mayaguez, PR 00680 USA. NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. Univ Puerto Rico, Dept Marine Sci, Mayaguez, PR 00709 USA. Univ Puerto Rico, Dept Elect & Comp Engn, Mayaguez, PR USA. Univ Puerto Rico, Dept Civil Engn, Mayaguez, PR USA. RP Ramirez-Beltran, ND (reprint author), Univ Puerto Rico, Dept Ind Engn, Mayaguez, PR 00680 USA. EM nazario@ece.uprm.edu RI Lau, William /E-1510-2012 OI Lau, William /0000-0002-3587-3691 NR 28 TC 3 Z9 3 U1 0 U2 2 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0027-0644 J9 MON WEATHER REV JI Mon. Weather Rev. PD MAR PY 2007 VL 135 IS 3 BP 877 EP 890 DI 10.1175/MWR3290.1 PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 150KB UT WOS:000245214600010 ER PT J AU Chin, AH Ahn, TS Li, HW Vaddiraju, S Bardeen, CJ Ning, CZ Sunkara, MK AF Chin, Alan H. Ahn, Tai S. Li, Hongwei Vaddiraju, Sreeram Bardeen, Christopher J. Ning, Cun-Zheng Sunkara, Mahendra K. TI Photoluminescence of GaN nanowires of different crystallographic orientations SO NANO LETTERS LA English DT Article ID GALLIUM NITRIDE NANOWIRES; GROWTH; SPECTROSCOPY; NANOCRYSTALS AB We utilized time-integrated and time-resolved photoluminescence of a-axis and c-axis gallium nitride nanowires to elucidate the origin of the blue-shifted ultraviolet photoluminescence in a-axis GaN nanowires relative to c-axis GaN nanowires. We attribute this blue-shifted ultraviolet photoluminescence to emission from surface trap states as opposed to previously proposed causes such as strain effects or built-in polarization. These results demonstrate the importance of accounting for surface effects when considering ultraviolet optoelectronic devices based on GaN nanowires. C1 NASA, Ames Res Ctr, Ctr Adv Aerosp Mat & Devices, Moffett Field, CA 94035 USA. Univ Calif Riverside, Dept Chem, Riverside, CA 92521 USA. Univ Louisville, Dept Chem Engn, Louisville, KY 40292 USA. RP Chin, AH (reprint author), NASA, Ames Res Ctr, Ctr Adv Aerosp Mat & Devices, Moffett Field, CA 94035 USA. EM achin@mail.arc.nasa.gov; cning@mail.arc.nasa.gov RI Sunkara, Mahendra/A-3033-2008; Ning, C. Z./D-4699-2009 OI Ning, C. Z./0000-0003-4583-8889 NR 20 TC 61 Z9 61 U1 2 U2 30 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1530-6984 J9 NANO LETT JI Nano Lett. PD MAR PY 2007 VL 7 IS 3 BP 626 EP 631 DI 10.1021/nl062524o PG 6 WC Chemistry, Multidisciplinary; Chemistry, Physical; Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Physics, Applied; Physics, Condensed Matter SC Chemistry; Science & Technology - Other Topics; Materials Science; Physics GA 145LU UT WOS:000244867400015 PM 17324001 ER PT J AU Masi, S Ade, PAR Bock, JJ Bond, JR Borrill, J Boscaleri, A Cabella, P Contaldi, CR Crill, BP de Bernardis, P De Gasperis, G De Oliveira-Costa, A De Troia, G Di Stefano, G Ehlers, P Hivon, E Hristov, V Iacoangeli, A Jaffe, AH Jones, WC Kisner, TS Lange, AE MacTavish, CJ Bettolo, CM Mason, P Mauskopf, PD Montroy, TE Nati, F Nati, L Natoli, P Netterfield, CB Pascale, E Piacentini, F Pogosyan, D Polenta, G Prunet, S Ricciardi, S Romeo, G Ruhl, JE Santini, P Tegmark, M Torbet, E Veneziani, M Vittorio, N AF Masi, S. Ade, P. A. R. Bock, J. J. Bond, J. R. Borrill, J. Boscaleri, A. Cabella, P. Contaldi, C. R. Crill, B. P. de Bernardis, P. De Gasperis, G. De Oliveira-Costa, A. De Troia, G. Di Stefano, G. Ehlers, P. Hivon, E. Hristov, V. Iacoangeli, A. Jaffe, A. H. Jones, W. C. Kisner, T. S. Lange, A. E. MacTavish, C. J. Bettolo, C. Marini Mason, P. Mauskopf, P. D. Montroy, T. E. Nati, F. Nati, L. Natoli, P. Netterfield, C. B. Pascale, E. Piacentini, F. Pogosyan, D. Polenta, G. Prunet, S. Ricciardi, S. Romeo, G. Ruhl, J. E. Santini, P. Tegmark, M. Torbet, E. Veneziani, M. Vittorio, N. TI The millimeter sky as seen with BOOMERanG SO NEW ASTRONOMY REVIEWS LA English DT Article; Proceedings Paper CT Francesco Melchiorri Memorial Conference CY APR 12-14, 2006 CL Univ Rome, Dept Phys, Rome, ITALY HO Univ Rome, Dept Phys DE cosmology; cosmic microwave background anisotropy and polarization; galactic foreground ID MICROWAVE BACKGROUND POLARIZATION; PROBE WMAP OBSERVATIONS; GALACTIC DUST EMISSION; ANGULAR POWER SPECTRUM; 2003 FLIGHT; COSMOLOGICAL PARAMETERS; TEMPERATURE ANISOTROPY; INFLATION; RADIATION; GAUSSIANITY AB BOOMERanG is a balloon-borne, mm-wave scanning telescope, which measured the first images of the CMB with sub-horizon resolution in 1998. In 2003 the instrument has been flown again with polarization sensitive bolometers, and has produced maps of the Stokes parameters I, Q, U of the microwave sky. Three regions of the southern sky were surveyed: a deep (similar to 90 square degrees) and a shallow survey (similar to 750 square degrees) at high Galactic latitudes, and a survey of similar to 300 square degrees across a southern section of the Galactic plane. The experiment measured simultaneously three wide frequency bands centered at 145, 245 and 345 GHz, with an angular resolution of similar to 10 degrees. The 145 GHz temperature maps are dominated by Cosmic Microwave Background (CMB) anisotropy, which is mapped with high signal to noise ratio. The map is consistent with the pattern measured in the same region by BOOMERanG-98 and by WMAP. At 145 GHz, in the high latitude surveys, the intensity and polarization of the astrophysical foregrounds are found to be negligible with respect to the cosmological signal. At 245 and 345 GHz we detect ISD emission correlated to the 3000 GHz IRAS/DIRBE maps. The Q and U maps at high latitudes are dominated by detector noise: a power spectrum analysis allows us to extract from the maps a significant CMB polarization signal. (c) 2006 Published by Elsevier B.V. C1 Univ Roma La Sapienza, Dipartimento Fis, Rome, Italy. Case Western Reserve Univ, Dept Phys, Cleveland, OH 44106 USA. Cardiff Univ, Dept Phys & Astron, Cardiff, Wales. CALTECH, Jet Prop Lab, Pasadena, CA USA. Univ Toronto, Canadian Inst Theoret Astrophys, Toronto, ON, Canada. LBNL, Computat Res Div, Berkeley, CA USA. CNR, IFAC, I-50127 Florence, Italy. CALTECH, IPAC, Pasadena, CA 91125 USA. Univ Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USA. Inst Astrophys, F-75014 Paris, France. Ist Nazl Geofis & Vulcanol, Rome, Italy. MIT, Dept Phys, Cambridge, MA 02139 USA. Univ Toronto, Dept Phys, Toronto, ON, Canada. CALTECH, Observ Cosmol, Pasadena, CA 91125 USA. Univ London Imperial Coll Sci Technol & Med, Theoret Phys Grp, London, England. Univ Roma Tor Vergata, Dipartimento Fis, I-00173 Rome, Italy. Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. Ist Nazl Fis Nucl, Sez Roma 1, Rome, Italy. Ist Nazl Fis Nucl, Sez Roma 2, Rome, Italy. Univ Alberta, Dept Phys, Edmonton, AB, Canada. RP Masi, S (reprint author), Univ Roma La Sapienza, Dipartimento Fis, Piazzale Aldo Moro 5, Rome, Italy. EM silvia.masi@roma1.infn.it RI Jaffe, Andrew/D-3526-2009; de Gasperis, Giancarlo/C-8534-2012; Nati, Federico/I-4469-2016; Piacentini, Francesco/E-7234-2010; OI de Gasperis, Giancarlo/0000-0003-2899-2171; Nati, Federico/0000-0002-8307-5088; Piacentini, Francesco/0000-0002-5444-9327; Santini, Paola/0000-0002-9334-8705; Ricciardi, Sara/0000-0002-3807-4043; Polenta, Gianluca/0000-0003-4067-9196; Masi, Silvia/0000-0001-5105-1439; de Bernardis, Paolo/0000-0001-6547-6446; ROMEO, Giovanni/0000-0002-5535-7803; Hivon, Eric/0000-0003-1880-2733 NR 46 TC 2 Z9 2 U1 0 U2 1 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 1387-6473 EI 1872-9630 J9 NEW ASTRON REV JI New Astron. Rev. PD MAR PY 2007 VL 51 IS 3-4 BP 236 EP 243 DI 10.1016/j.newar.2006.11.063 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 148AD UT WOS:000245046000007 ER PT J AU Piacentini, F Ade, PAR Bock, JJ Bond, JR Borrill, J Boscaleri, A Cabella, P Contaldi, CR Crill, BP de Bernardis, P De Gasperis, G de Oliveira-Costa, A De Troia, G Di Stefano, G Hivon, E Jaffe, AH Kisner, TS Jones, WC Lange, AE Marini-Bettolo, C Masi, S Mauskopf, PD MacTavish, CJ Melchiorri, A Montroy, TE Nati, F Nati, L Natoli, P Netterfield, CB Pascale, E Pogosyan, D Polenta, G Prunet, S Ricciardi, S Romeo, G Ruhl, JE Santini, P Tegmark, M Veneziam, M Vittorio, N AF Piacentini, F. Ade, P. A. R. Bock, J. J. Bond, J. R. Borrill, J. Boscaleri, A. Cabella, P. Contaldi, C. R. Crill, B. P. de Bernardis, P. De Gasperis, G. de Oliveira-Costa, A. De Troia, G. Di Stefano, G. Hivon, E. Jaffe, A. H. Kisner, T. S. Jones, W. C. Lange, A. E. Marini-Bettolo, C. Masi, S. Mauskopf, P. D. MacTavish, C. J. Melchiorri, A. Montroy, T. E. Nati, F. Nati, L. Natoli, P. Netterfield, C. B. Pascale, E. Pogosyan, D. Polenta, G. Prunet, S. Ricciardi, S. Romeo, G. Ruhl, J. E. Santini, P. Tegmark, M. Veneziam, M. Vittorio, N. TI CMB polarization with BOOMERANG 2003 SO NEW ASTRONOMY REVIEWS LA English DT Article; Proceedings Paper CT Francesco Melchiorri Memorial Conference CY APR 12-14, 2006 CL Univ Rome, Dept Phys, Rome, ITALY HO Univ Rome, Dept Phys DE cosmology; CMB; polarization ID GALACTIC DUST EMISSION; MICROWAVE BACKGROUND-RADIATION; MAP-MAKING ALGORITHM; POWER SPECTRUM; DATA SETS; INSTRUMENT; ANISOTROPY; ARCHEOPS; RECEIVER; UNIVERSE AB This paper reports results from the BOOMERANG 2003 flights, devoted to the measurement of intensity and polarization of the cosmic microwave background radiation. In particular, it is focused on the power angular power spectra and on the control of possible contamination from systematic effects and foregrounds. (c) 2006 Elsevier B.V. All rights reserved. C1 Univ Roma La Sapienza, Dipartimento Fis, Rome, Italy. Case Western Reserve Univ, Dept Phys, Cleveland, OH 44106 USA. Univ Cardiff Wales, Dept Phys & Astron, Cardiff, Wales. CALTECH, Jet Prop Lab, Pasadena, CA USA. Univ Toronto, Canadian Inst Theoret Astrophys, Toronto, ON M5S 3H8, Canada. LBNL, Computat Res Div, Berkeley, CA USA. CNR, Ist Fis Applicata Nello Carrara, I-50127 Florence, Italy. CALTECH, IPAC, Pasadena, CA 91125 USA. Univ Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USA. Inst Astrophys, F-75014 Paris, France. Ist Nazl Geofis & Vulcanol, Rome, Italy. MIT, Dept Phys, Cambridge, MA 02139 USA. Univ Toronto, Dept Phys, Toronto, ON, Canada. CALTECH, Observat Cosmol, Pasadena, CA 91125 USA. Univ London Imperial Coll Sci Technol & Med, Theoret Phys Grp, London, England. Univ Roma Tor Vergata, Dipartimento Fis, I-00173 Rome, Italy. Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. Ist Nazl Fis Nucl, Sez Roma 1, Rome, Italy. Ist Nazl Fis Nucl, Sez Roma 2, Rome, Italy. Univ Alberta, Dept Phys, Edmonton, AB, Canada. RP Piacentini, F (reprint author), Univ Roma La Sapienza, Dipartimento Fis, Piazzale Aldo Moro 5, Rome, Italy. EM francesco.piacentini@roma1.infn.it RI Jaffe, Andrew/D-3526-2009; de Gasperis, Giancarlo/C-8534-2012; Nati, Federico/I-4469-2016; Piacentini, Francesco/E-7234-2010; OI Hivon, Eric/0000-0003-1880-2733; de Gasperis, Giancarlo/0000-0003-2899-2171; Nati, Federico/0000-0002-8307-5088; Piacentini, Francesco/0000-0002-5444-9327; Ricciardi, Sara/0000-0002-3807-4043; Masi, Silvia/0000-0001-5105-1439; de Bernardis, Paolo/0000-0001-6547-6446; ROMEO, Giovanni/0000-0002-5535-7803; Polenta, Gianluca/0000-0003-4067-9196; Santini, Paola/0000-0002-9334-8705 NR 34 TC 2 Z9 2 U1 0 U2 1 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 1387-6473 J9 NEW ASTRON REV JI New Astron. Rev. PD MAR PY 2007 VL 51 IS 3-4 BP 244 EP 249 DI 10.1016/j.newar.2006.11.058 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 148AD UT WOS:000245046000008 ER PT J AU De Troia, G Ade, PAR Bock, JJ Bond, JR Borrill, J Boscaleri, A Cabella, P Contaldi, CR Crill, BP de Bernardis, P de Gasperis, G de Oliveira-Costa, A Di Stefano, G Ferreira, PG Hivon, E Jaffe, A Kisner, T Kunz, M Jones, WC Lange, AE Masi, S Mauskopf, PD MacTavish, C Melchiorri, A Montroy, T Natoli, P Netterfield, CB Pascale, E Piacentini, F Pogosyan, D Polenta, G Prunet, S Ricciardi, S Romeo, G Ruhl, JE Santini, P Tegmark, M Veneziani, M Vittorio, N AF De Troia, G. Ade, P. A. R. Bock, J. J. Bond, J. R. Borrill, J. Boscaleri, A. Cabella, P. Contaldi, C. R. Crill, B. P. de Bernardis, P. de Gasperis, G. de Oliveira-Costa, A. Di Stefano, G. Ferreira, P. G. Hivon, E. Jaffe, A. Kisner, T. Kunz, M. Jones, W. C. Lange, A. E. Masi, S. Mauskopf, P. D. MacTavish, C. Melchiorri, A. Montroy, T. Natoli, P. Netterfield, C. B. Pascale, E. Piacentini, F. Pogosyan, D. Polenta, G. Prunet, S. Ricciardi, S. Romeo, G. Ruhl, J. E. Santini, P. Tegmark, M. Veneziani, M. Vittorio, N. TI Searching for non-Gaussian signals in the BOOMERanG 2003 CMB map: Preliminary results SO NEW ASTRONOMY REVIEWS LA English DT Article CT Francesco Melchiorri Memorial Conference CY APR 12-14, 2006 CL Univ Rome, Dept Phys, Rome, ITALY HO Univ Rome, Dept Phys ID POWER SPECTRUM; FLIGHT; ANISOTROPY AB We analyse the 145 GHz temperature map produced from the 2003 flight of BOOMERanG in search for deviations from Gaussianity. We perform a pixel space analysis computing the map's skewness, kurtosis and Minkowski functionals, as well as a Fourier space analysis computing the diagonal part the of angular bispectrum. The preliminary results presented here suggest that the data are fully consistent with the Gaussian hypothesis. (c) 2006 Elsevier B.V. All rights reserved. C1 Univ Roma La Sapienza, Dipartimento Fis, I-00185 Rome, Italy. Cardiff Univ, Dept Phys & Astron, Cardiff CF24 3YB, Wales. Jet Prop Lab, Pasadena, CA USA. Univ Toronto, Canadian Inst Theoret Astrophys, Toronto, ON, Canada. Univ Calif Berkeley, Lawrence Berkeley Lab, Computat Res Div, Berkeley, CA 94720 USA. CNR, IFAC, Florence, Italy. Univ Oxford, Dept Astrophys, Oxford OX1 3RH, England. CALTECH, IPAC, Pasadena, CA 91125 USA. Univ Roma Tor Vergata, Dipartimento Fis, I-00133 Rome, Italy. MIT, Dept Phys, Cambridge, MA 02139 USA. Ist Nazl Geofis & Vulcanol, Rome, Italy. Univ London Imperial Coll Sci Technol & Med, Theoret Phys Grp, London, England. Case Western Reserve Univ, Dept Phys, Cleveland, OH 44106 USA. Univ Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USA. Univ Geneva, Dept Phys Theor, Geneva 4, Switzerland. CALTECH, Observ Cosmol, Pasadena, CA 91125 USA. Univ Toronto, Dept Phys, Toronto, ON, Canada. Ist Nazl Fis Nucl, Sez Roma 1, Rome, Italy. Ist Nazl Fis Nucl, Sez Roma 2, Rome, Italy. Univ Alberta, Dept Phys, Edmonton, AB, Canada. Inst Astrophys, F-75014 Paris, France. RP de Bernardis, P (reprint author), Univ Roma La Sapienza, Dipartimento Fis, Piazzale A Moro 2, I-00185 Rome, Italy. EM paolo.debernardis@roma1.infn.it RI Jaffe, Andrew/D-3526-2009; de Gasperis, Giancarlo/C-8534-2012; Piacentini, Francesco/E-7234-2010; OI Hivon, Eric/0000-0003-1880-2733; Santini, Paola/0000-0002-9334-8705; de Gasperis, Giancarlo/0000-0003-2899-2171; Piacentini, Francesco/0000-0002-5444-9327; Polenta, Gianluca/0000-0003-4067-9196; Masi, Silvia/0000-0001-5105-1439; de Bernardis, Paolo/0000-0001-6547-6446; ROMEO, Giovanni/0000-0002-5535-7803; Ricciardi, Sara/0000-0002-3807-4043 NR 20 TC 3 Z9 3 U1 0 U2 0 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 1387-6473 J9 NEW ASTRON REV JI New Astron. Rev. PD MAR PY 2007 VL 51 IS 3-4 BP 250 EP 255 DI 10.1016/j.newar.2006.11.064 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 148AD UT WOS:000245046000009 ER PT J AU Challinor, A Lewis, A Rocha, G Smith, S AF Challinor, Anthony Lewis, Antony Rocha, Graca Smith, Sarah TI Information content of the lensed CMB power spectra SO NEW ASTRONOMY REVIEWS LA English DT Article; Proceedings Paper CT Francesco Melchiorri Memorial Conference CY APR 12-14, 2006 CL Univ Rome, Dept Phys, Rome, ITALY HO Univ Rome, Dept Phys ID MICROWAVE BACKGROUND ANISOTROPIES; PARAMETER-ESTIMATION; POLARIZATION; REIONIZATION AB Weak lensing of the cosmic microwave background (CMB) is expected to be detected with the next generation of observations. We review recent theoretical refinements in the calculation of the lensed spectra and discuss the extent to which these corrections are required to avoid parameter biases from future data. For a future satellite mission (with similar to 1 mu K' sensitivity), targeting large-angle B modes from gravitational waves, the flat-sky and gradient approximations must be dropped and non-linear matter clustering included if r is near the detection threshold (r similar to 2 x 10(-4)). We also discuss the role of the lensed CMB spectra in constraining cosmological parameters, such as light neutrino masses and the dark energy model, that are essentially degenerate with respect to the primary CMB fluctuations. NonGaussianities and degeneracies limit what can be learned from the lensed spectra, but a simple power spectrum analysis will still be a worthwhile first step. Analysing futuristic, cosmic-variance-limited lensed B-mode spectra requires careful attention to the choice of likelihood approximation. We show that approximations in current use for the analysis of Gaussian fields produce biased results on lensed simulations. We highlight a more refined approximation that performs significantly better. (c) 2006 Elsevier B.V. All rights reserved. C1 Univ Cambridge, Inst Astron, Cambridge CB3 0HA, England. Univ Cambridge, Cavendish Lab, Astrophys Grp, Cambridge CB3 0HE, England. CALTECH, Observat Cosmol, Pasadena, CA 91125 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Challinor, A (reprint author), Univ Cambridge, Inst Astron, Madingley Rd, Cambridge CB3 0HA, England. EM a.d.challinor@ast.cam.ac.uk NR 36 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 1387-6473 J9 NEW ASTRON REV JI New Astron. Rev. PD MAR PY 2007 VL 51 IS 3-4 BP 421 EP 430 DI 10.1016/j.newar.2006.11.070 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 148AD UT WOS:000245046000037 ER PT J AU Adriani, O Albi, M Altamura, F Ambriola, M Bakaldin, A Barbarino, GC Basili, A Bazilevskaja, G Bellotti, R Bencardino, R Boezio, M Bogomolov, E Bonechi, L Bongi, M Bongiorno, L Bonvicini, V Boscherini, M Bottai, S Cafagna, F Campana, D Carlson, P Casolino, M Castellini, G Circella, M De Marzo, C De Pascale, MP Fedele, D Galper, AM Grigorjeva, A Grandi, M Hofverberg, P Koldashov, SV Korotkov, MG Krutkov, S Lund, J Lundquist, J Malvezzi, V Marcelli, L Menn, W Mikhailov, VV Minori, M Mitchell, JW Mocchiutti, E Morselli, A Mukhametshin, R Nagni, M Orsi, S Osteria, G Papini, P Pearce, M Picozza, P Ricci, M Ricciarini, S Russo, S Schiavon, P Simon, M Spillantini, P Sparvoli, R Stephens, SA Stochaj, SJ Stozhkov, RY Streitmatter, E Taddei, E Vacchi, A Vannuccini, E Vasiljev, G Voronov, SA Yurkin, Y Zampa, G Zampa, N AF Adriani, O. Albi, M. Altamura, F. Ambriola, M. Bakaldin, A. Barbarino, G. C. Basili, A. Bazilevskaja, G. Bellotti, R. Bencardino, R. Boezio, M. Bogomolov, E. Bonechi, L. Bongi, M. Bongiorno, L. Bonvicini, V. Boscherini, M. Bottai, S. Cafagna, F. Campana, D. Carlson, P. Casolino, M. Castellini, G. Circella, M. De Marzo, C. De Pascale, M. P. Fedele, D. Galper, A. M. Grigorjeva, A. Grandi, M. Hofverberg, P. Koldashov, S. V. Korotkov, M. G. Krutkov, S. Lund, J. Lundquist, J. Malvezzi, V. Marcelli, L. Menn, W. Mikhailov, V. V. Minori, M. Mitchell, J. W. Mocchiutti, E. Morselli, A. Mukhametshin, R. Nagni, M. Orsi, S. Osteria, G. Papini, P. Pearce, M. Picozza, P. Ricci, M. Ricciarini, S. Russo, S. Schiavon, P. Simon, M. Spillantini, P. Sparvoli, R. Stephens, S. A. Stochaj, S. J. Stozhkov, R. Y. Streitmatter, E. Taddei, E. Vacchi, A. Vannuccini, E. Vasiljev, G. Voronov, S. A. Yurkin, Y. Zampa, G. Zampa, N. TI The Pamela experiment ready for flight SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 10th Pisa Meeting on Advanced Detectors CY MAY 21-27, 2006 CL La Biodola, ITALY DE cosmic rays; antiprotons; magnetic spectrometer; calorimeter AB The Pamela apparatus will allow precise measurements of cosmic rays in Low Earth Orbit, mainly focusing on the antiparticles component. The apparatus is now ready for flight, and the launch is foreseen during June 2006. The paper briefly reports the status of the experiment, and the performances of the various components as measured before the launch. (c) 2006 Elsevier B.V. All rights reserved. C1 Ist Nazl Fis Nucl, I-50125 Florence, Italy. Univ Florence, I-50121 Florence, Italy. Ist Nazl Fis Nucl, Trieste, Italy. Ist Nazl Fis Nucl, Rome, Italy. Univ Roma Tor Vergata, Rome, Italy. Ist Nazl Fis Nucl, I-70126 Bari, Italy. Univ Bari, I-70121 Bari, Italy. Moscow Engn & Phys Inst, Moscow, Russia. Ist Nazl Fis Nucl, I-80125 Naples, Italy. Univ Naples Federico II, Naples, Italy. Royal Inst Technol, KTH, Dept Phys, Stockholm, Sweden. CNR, Ist Fis Applicata, I-00185 Rome, Italy. Univ Siegen, D-57068 Siegen, Germany. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Ist Nazl Fis Nucl, Lab Nazl Frascati, I-00044 Frascati, Italy. Tata Inst Fundamental Res, Bombay 400005, Maharashtra, India. New Mexico State Univ, Las Cruces, NM 88003 USA. RP Adriani, O (reprint author), Ist Nazl Fis Nucl, I-50125 Florence, Italy. EM adriani@fi.infn.it RI Morselli, Aldo/G-6769-2011; Cafagna, Francesco/A-9299-2010; Voronov, Sergey/P-9654-2016; Mocchiutti, Emiliano/I-8049-2013; Mikhailov, Vladimir/B-5368-2014; Vasilyev, Gennady/E-4843-2014; Krutkov, Sergey/E-7561-2014; Vacchi, Andrea/C-1291-2010; Barbarino, Giancarlo/L-2559-2015; Bongi, Massimo/L-9417-2015; Galper, Arkady/M-9610-2015; marcelli, laura/K-8860-2016; OI Bellotti, Roberto/0000-0003-3198-2708; casolino, marco/0000-0001-6067-5104; Ricciarini, Sergio Bruno/0000-0001-6176-3368; Castellini, Guido/0000-0002-0177-0643; Sparvoli, Roberta/0000-0002-6314-6117; Picozza, Piergiorgio/0000-0002-7986-3321; Papini, Paolo/0000-0003-4718-2895; Morselli, Aldo/0000-0002-7704-9553; Cafagna, Francesco/0000-0002-7450-4784; Voronov, Sergey/0000-0002-9209-0618; Mocchiutti, Emiliano/0000-0001-7856-551X; Mikhailov, Vladimir/0000-0003-3851-2901; Vacchi, Andrea/0000-0003-3855-5856; Barbarino, Giancarlo/0000-0001-9253-3397; Bongi, Massimo/0000-0002-6050-1937; marcelli, laura/0000-0002-3180-1228; Boezio, Mirko/0000-0002-8015-2981 NR 3 TC 1 Z9 1 U1 1 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD MAR 1 PY 2007 VL 572 IS 1 BP 471 EP 473 DI 10.1016/j.nima.2006.10.316 PG 3 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 149EI UT WOS:000245129400155 ER PT J AU Emfietzoglou, D Nikjoo, H Petsalakis, ID Pathak, A AF Emfietzoglou, D. Nikjoo, H. Petsalakis, I. D. Pathak, A. TI A consistent dielectric response model for water ice over the whole energy-momentum plane SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 22nd International Conference on Atomic Collisions in Solids CY JUL 21-26, 2006 CL Tech Univ Berlin, Berlin, GERMANY HO Tech Univ Berlin DE dielectric function; solid water; ice ID X-RAY-SCATTERING; MEAN FREE PATHS; LIQUID WATER; ELECTRONIC-STRUCTURE; CROSS-SECTIONS; VACUUM ULTRAVIOLET; STOPPING POWERS; PROTONS; SOLIDS; EXCITATIONS AB We have developed, for the first time, a consistent analytic model for the complex dielectric response function, epsilon, of amorphous and hexagonal ice over the complete energy-momentum plane. The energy dependence at the optical limit is based on a parametrization of all dielectric data representations, namely Im(epsilon), Re(epsilon) and Im(-1/epsilon), using a linear combination of Drude-type functions associated with the various interband transitions. The "fitting" procedure is forced to self-consistency by the fulfillment (to within 1%) of the f-sum-rules for Im(epsilon) and Im(-1/epsilon). The momentum dependence is provided by appropriate dispersion relationships for the Drude coefficients obtained from our recent analysis of the experimental Bethe ridge of liquid water. Time-dependent density functional theory (TDDFT) calculations of the optical oscillator strength (up to 20 eV) of H2O clusters are also presented for comparison. It is expected that the present development will permit accurate calculations of inelastic scattering probabilities and associated quantities (e.g. stopping forces) of swift charges in solid water. (c) 2006 Elsevier B.V. All rights reserved. C1 Univ Hyderabad, Sch Phys, Hyderabad 500046, Andhra Pradesh, India. Natl Hellen Res Fdn, Inst Phys & Theoret Chem, Athens 11635, Greece. NASA, Lyndon B Johnson Space Ctr, Ctr Adv Space Studies, USRA, Houston, TX 77058 USA. Univ Ioannina, Med Phys Lab, Sch Med, GR-45110 Ioannina, Greece. RP Pathak, A (reprint author), Univ Hyderabad, Sch Phys, Hyderabad 500046, Andhra Pradesh, India. EM appsp@uohyd.ernet.in RI Emfietzoglou, Dimitris/G-7168-2012; nhrf, tpci/M-8699-2013 NR 39 TC 5 Z9 5 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-583X J9 NUCL INSTRUM METH B JI Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms PD MAR PY 2007 VL 256 IS 1 BP 141 EP 147 DI 10.1016/j.nimb.2006.11.105 PG 7 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 160RF UT WOS:000245959300030 ER PT J AU Herren, KA Gregory, DA AF Herren, Kenneth A. Gregory, Don A. TI Mie scattering of growing molecular contaminants SO OPTICAL ENGINEERING LA English DT Article DE scattering; vacuum ultraviolet; contamination; molecular contamination AB Molecular contamination of optical surfaces from outgassed material has been shown in many cases to proceed from acclimation centers and to produce many roughly hemispherical '' islands '' of contamination on the surface. The mathematics of the hemispherical scattering is simplified by introducing a virtual source below the plane of the optic, in this case a mirror, allowing the use of Mie theory to produce a solution for the resulting sphere in transmission. Experimentally, a fixed wavelength in the vacuum ultraviolet was used as the illumination source and scattered light from the polished and coated glass mirrors was detected at a fixed angle as the contamination islands grew in time. (C) 2007 Society of Photo-Optical Instrumentation Engineers. C1 NASA, George C Marshall Space Flight Ctr, Natl Space Sci & Technol Ctr, Huntsville, AL 35812 USA. Univ Alabama, Dept Phys, Huntsville, AL 35899 USA. RP Herren, KA (reprint author), NASA, George C Marshall Space Flight Ctr, Natl Space Sci & Technol Ctr, Huntsville, AL 35812 USA. NR 14 TC 1 Z9 1 U1 0 U2 3 PU SPIE-SOCIETY PHOTOPTICAL INSTRUMENTATION ENGINEERS PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98225 USA SN 0091-3286 J9 OPT ENG JI Opt. Eng. PD MAR PY 2007 VL 46 IS 3 AR 033602 DI 10.1117/1.2715944 PG 9 WC Optics SC Optics GA 166BG UT WOS:000246351400009 ER PT J AU Savchenkov, AA Matsko, AB Mohageg, M Maleki, L AF Savchenkov, Anatoliy A. Matsko, Andrey B. Mohageg, Makan Maleki, Lute TI Ringdown spectroscopy of stimulated Raman scattering in a whispering gallery mode resonator SO OPTICS LETTERS LA English DT Article ID MICROCAVITIES AB We report experimental observations of power-dependent, nonexponential decay of light stored in whispering gallery modes caused by stimulated Raman scattering in the resonator host material. Specifically, we show that the instantaneous decay rate of whispering gallery modes of a calcium fluoride resonator increases as the amount of light stored in the resonator decreases. (c) 2007 Optical Society of America. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Savchenkov, AA (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM Andrey.Matsko@jpl.nasa.gov RI Matsko, Andrey/A-1272-2007 NR 10 TC 33 Z9 33 U1 1 U2 15 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 0146-9592 J9 OPT LETT JI Opt. Lett. PD MAR 1 PY 2007 VL 32 IS 5 BP 497 EP 499 DI 10.1364/OL.32.000497 PG 3 WC Optics SC Optics GA 202XB UT WOS:000248936600019 PM 17392900 ER PT J AU Fensholt, R Anyamba, A Stisen, S Sandholt, I Pak, E Small, J AF Fensholt, Rasmus Anyamba, Assaf Stisen, Simon Sandholt, Inge Pak, Ed Small, Jennifer TI Comparisons of compositing period length for vegetation index data from polar-orbiting and geostationary satellites for the cloud-prone region of West Africa SO PHOTOGRAMMETRIC ENGINEERING AND REMOTE SENSING LA English DT Article ID IN-SITU MEASUREMENTS; AVHRR DATA; SEMIARID ENVIRONMENT; MODIS; SAHEL AB Land surface data from MODIS and AVHRR have been extensively used for vegetation monitoring. In cloud-prone areas like West Africa the use of Normalized Difference Vegetation Index (NDVI) data for vegetation monitoring is hampered by persistent cloud cover especially during the rainy season. The new geostationary satellite Meteosat Second Generation (SEVIRI MSG) is the first geostationary satellite suited for vegetation monitoring allowing NDVI to be derived with a 15-minute temporal resolution. For West Africa, MODIS (combined TERRA and AQUA) produce above 85 percent cloud-free pixels in the scene during the entire rainy season using 16-day composite periods. SEVIRI MSG data produces >98 percent cloud-free pixels during the entire season using a 3-day composite period. Therefore, there is a much higher probability for producing high quality cloud free data using SEVIRI MSG data for a short time composite period compared to Polar Orbiting Environmental Satellite (POES) data, which is expected to substantially improve various applications of satellite based natural resource management, including vegetation monitoring, in West Africa. C1 Univ Copenhagen, Inst Geog, DK-1350 Copenhagen, Denmark. NASA, Goddard Space Flight Ctr, Biospher Sci Branch, Greenbelt, MD 20771 USA. RP Fensholt, R (reprint author), Univ Copenhagen, Inst Geog, Oster Voldgade 10, DK-1350 Copenhagen, Denmark. EM rf@geogr.ku.dk RI Fensholt, Rasmus/L-7951-2014 OI Fensholt, Rasmus/0000-0003-3067-4527 NR 30 TC 21 Z9 22 U1 0 U2 3 PU AMER SOC PHOTOGRAMMETRY PI BETHESDA PA 5410 GROSVENOR LANE SUITE 210, BETHESDA, MD 20814-2160 USA SN 0099-1112 J9 PHOTOGRAMM ENG REM S JI Photogramm. Eng. Remote Sens. PD MAR PY 2007 VL 73 IS 3 BP 297 EP 309 PG 13 WC Geography, Physical; Geosciences, Multidisciplinary; Remote Sensing; Imaging Science & Photographic Technology SC Physical Geography; Geology; Remote Sensing; Imaging Science & Photographic Technology GA 139WY UT WOS:000244464600010 ER PT J AU Bhatia, AK AF Bhatia, A. K. TI Hybrid theory of electron-hydrogen elastic scattering SO PHYSICAL REVIEW A LA English DT Article ID STATES; ATOMS AB We report on a study of electron-hydrogen scattering, using a combination of a modified method of polarized orbitals and the optical potential formalism which does not require projection operators. The calculation is restricted to S waves in the elastic region, where the correlation functions are of Hylleraas type. It is found that the phase shifts are not significantly affected by the modification of the target function by a method similar to the method of polarized orbitals and they are close to the phase shifts calculated earlier by Bhatia and Temkin [Phys. Rev. A 64, 032709 (2001)]. This indicates that the correlation function is general enough to include the target distortions (polarization) in the presence of the incident electron, except for the scattering lengths for which the inclusion of polarization is essential for precision results. Results for the phase shifts, obtained in the present hybrid formalism, are rigorous lower bounds to the exact phase shifts. C1 NASA, Goddard Space Flight Ctr, Heliophys Sci Div, Greenbelt, MD 20771 USA. RP Bhatia, AK (reprint author), NASA, Goddard Space Flight Ctr, Heliophys Sci Div, Greenbelt, MD 20771 USA. NR 18 TC 12 Z9 12 U1 1 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD MAR PY 2007 VL 75 IS 3 AR 032713 DI 10.1103/PhysRevA.75.032713 PG 7 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 151YE UT WOS:000245326300119 ER PT J AU Mawhorter, RJ Chutjian, A Cravens, TE Djuric, N Hossain, S Lisse, CM MacAskill, JA Smith, SJ Simcic, J Williams, ID AF Mawhorter, R. J. Chutjian, A. Cravens, T. E. Djuric, N. Hossain, S. Lisse, C. M. MacAskill, J. A. Smith, S. J. Simcic, J. Williams, I. D. TI Absolute single and multiple charge exchange cross sections for highly charged C, O, and Ne ions on H(2)O, CO, and CO(2) SO PHYSICAL REVIEW A LA English DT Article ID X-RAY-EMISSION; WIND-COMET INTERACTIONS; ELECTRON-CAPTURE; ATOMIC-HYDROGEN; COLLISIONS; ENERGY; SPECTRA; IMPACT; DISSOCIATION; SPECTROSCOPY AB Reported herein are measured absolute single, double, and triple charge exchange (CE) cross sections for the highly charged ions (HCIs) C(q+) (q=5,6), O(q+) (q=6,7,8), and Ne(q+) (q=7,8) colliding with the molecular species H(2)O, CO, and CO(2). Present data can be applied to interpreting observations of x-ray emissions from comets as they interact with the solar wind. As such, the ion impact energies of 7.0q keV (1.62-3.06 keV/amu) are representative of the fast solar wind, and data at 1.5q keV for O(6+) (0.56 keV/amu) on CO and CO(2) and 3.5q keV for O(5+) (1.09 keV/amu) on CO provide checks of the energy dependence of the cross sections at intermediate and typical slow solar wind velocities. The HCIs are generated within a 14 GHz electron cyclotron resonance ion source. Absolute CE measurements are made using a retarding potential energy analyzer, with measurement of the target gas cell pressure and incident and final ion currents. Trends in the cross sections are discussed in light of the classical overbarrier model (OBM), extended OBM, and with recent results of the classical trajectory Monte Carlo theory. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Pomona Coll, Dept Phys & Astron, Claremont, CA 91711 USA. Univ Kansas, Dept Phys & Astron, Lawrence, KS 66045 USA. Johns Hopkins Univ, Appl Phys Lab, Space Dept, Laurel, MD 20723 USA. Queens Univ Belfast, Dept Phys, Belfast BT7 1NN, Antrim, North Ireland. RP Mawhorter, RJ (reprint author), CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RI Lisse, Carey/B-7772-2016 OI Lisse, Carey/0000-0002-9548-1526 NR 55 TC 26 Z9 26 U1 0 U2 6 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD MAR PY 2007 VL 75 IS 3 AR 032704 DI 10.1103/PhysRevA.75.032704 PG 7 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 151YE UT WOS:000245326300110 ER PT J AU Bauschlicher, CW Lawson, JW AF Bauschlicher, Charles W., Jr. Lawson, John W. TI Current-voltage curves for molecular junctions: Effect of substitutients SO PHYSICAL REVIEW B LA English DT Article ID BASIS-SETS; OLIGO(PHENYLENE ETHYNYLENE)S; ELECTRONIC DEVICES; POTENTIALS; FORMALISM; EXCHANGE; ENERGY; ATOMS AB We present current-voltage (I-V) curves for phenylene ethynylene oligomers between two Au surfaces computed using a density-functional-theory-Green's-function approach. In addition to the parent molecule, two different substitutients are considered: one where all the hydrogens are replaced by chlorines and a second where one H is replaced by an NO(2) group. In this way, we can study the difference between electron withdrawing and pi orbital effects. For low biases, a reduced current for the derived species is consistent with a shift of the highest occupied molecular orbital (HOMO) to lower energy due to the electron withdrawal by Cl or NO(2). At higher biases, the lowest unccupied molecular orbital (LUMO) becomes important, and the Cl and NO(2) substituted species carry more current than the parent because the LUMO is stabilized (shifted to lower energy) due to the withdrawal of electrons by the Cl and NO(2). In these molecules, the C(2) bridging units as well as the thiol anchor group are shown to create bottlenecks to current flow. C1 NASA, Ames Res Ctr, Ctr Adv Mat & Devices, Moffett Field, CA 94035 USA. RP Bauschlicher, CW (reprint author), NASA, Ames Res Ctr, Ctr Adv Mat & Devices, Mail Stop 230-3, Moffett Field, CA 94035 USA. EM Charles.W.Bauschlicher@nasa.gov; John.W.Lawson@nasa.gov NR 23 TC 17 Z9 17 U1 0 U2 1 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 J9 PHYS REV B JI Phys. Rev. B PD MAR PY 2007 VL 75 IS 11 AR 115406 DI 10.1103/PhysRevB.75.115406 PG 6 WC Physics, Condensed Matter SC Physics GA 151ZK UT WOS:000245329600111 ER PT J AU Camp, JB Cannizzo, JK Numata, K AF Camp, Jordan B. Cannizzo, John K. Numata, Kenji TI Application of the Hilbert-Huang transform to the search for gravitational waves SO PHYSICAL REVIEW D LA English DT Article ID LIGO; INTERFEROMETER AB We present the application of a novel method of time-series analysis, the Hilbert-Huang transform, to the search for gravitational waves. This algorithm is adaptive and does not impose a basis set on the data, and thus the time-frequency decomposition it provides is not limited by time-frequency uncertainty spreading. Because of its high time-frequency resolution it has important applications to both signal detection and instrumental characterization. Applications to the data analysis of the ground and space based gravitational wave detectors, LIGO and LISA, are described. C1 Goddard Space Flight Ctr, Lab Gravitat Phys, Greenbelt, MD 20771 USA. RP Camp, JB (reprint author), Univ Maryland, Dept Phys, Baltimore, MD 21250 USA. EM camp@lheapop.gsfc.nasa.gov NR 15 TC 13 Z9 13 U1 0 U2 1 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1550-7998 EI 1550-2368 J9 PHYS REV D JI Phys. Rev. D PD MAR PY 2007 VL 75 IS 6 AR 061101 DI 10.1103/PhysRevD.75.061101 PG 5 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 152AW UT WOS:000245333600001 ER PT J AU Choueiri, EY Randolph, TM AF Choueiri, Edgar Y. Randolph, Thomas M. TI Ionization front in a high-current gas discharge SO PHYSICS OF PLASMAS LA English DT Article ID MAGNETOPLASMADYNAMIC THRUSTER; MAGNETIC-FIELD; MPD THRUSTERS; PLASMA; ACCELERATION; ARGON AB Spectroscopic measurements of ion/neutral density ratio profiles are made inside the high-current, low-pressure discharge of a coaxial magnetoplasmadynamic thruster and show the existence of a thin ionization front, upstream in the discharge, that effectively ionizes the incoming gas to ionization levels above 50%. The measurements allow an estimate of the width of this ionization front to be on the order of a few millimeters. Due to the known existence of microturbulence in the plasma, which can produce suprathermal electrons, an explanation of the measurements based on the existence of a suprathermal tail in the electron energy distribution function is sought. A theoretical model for the width of the ionization front is combined with a multilevel excitation model for argon and shows that a Maxwellian electron distribution function cannot account for the small length scale of the ionization front, and that the latter is more consistent with an electron distribution function having a suprathermal population, the magnitude of which is estimated by comparing the model to the experiments. (c) 2007 American Institute of Physics. C1 Princeton Univ, Elect Prop & Plasma Dynam Lab, Princeton, NJ 08544 USA. NASA, Jet Prop Lab, Pasadena, CA 91109 USA. RP Choueiri, EY (reprint author), Princeton Univ, Elect Prop & Plasma Dynam Lab, Princeton, NJ 08544 USA. NR 40 TC 3 Z9 3 U1 0 U2 1 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD MAR PY 2007 VL 14 IS 3 AR 033502 DI 10.1063/1.2646365 PG 11 WC Physics, Fluids & Plasmas SC Physics GA 151VX UT WOS:000245320000037 ER PT J AU Ehrenfreund, P Ruiterkamp, R Peeters, Z Foing, B Salama, F Martins, Z AF Ehrenfreund, Pascale Ruiterkamp, Richard Peeters, Zan Foing, Bernard Salama, Farid Martins, Zita TI The ORGANICS experiment on BIOPAN V: UV and space exposure of aromatic compounds SO PLANETARY AND SPACE SCIENCE LA English DT Article DE PAHs; interstellar molecules; space research; low earth orbit exposure; biopan; International Space Station; photo-stability ID DIFFUSE INTERSTELLAR-MEDIUM; CARBON; PAHS; PHOTODESTRUCTION; HYDROCARBONS; CLOUDS; PHOTODISSOCIATION; HYDROGENATION; MOLECULES; FEATURES AB We studied the stability of aromatic compounds in low Earth orbit environment and describe the scientific results and successful flight of the ORGANICS experiment on-board the BIOPAN V space exposure facility. This experiment investigated the photo stability of large organic molecules in low Earth orbit. Thin films of selected organic molecules, such as polycyclic aromatic hydrocarbons (PAHs) and the fullerene C-60 were subjected to the low Earth orbit environment and the samples were monitored before and after flight. PAHs and fullerenes have been proposed as carriers for a number of astronomical absorption and emission features and are also identified in meteorites. Our experiment on BIOPAN V was exposed to a total fluence of 602.45 kJ m(-2) for photons in the range 170-280 nm. The experiment was also intended as a hardware test-flight for a long-term exposure experiment (Survival of organics in space) on the EXPOSE facility on the International Space Station (ISS). For the small fluence that was collected during the BIOPAN V experiment we found little evidence of photo-destruction. The results confirm that PAH molecules are very stable compounds in space. The small differences in destruction rates that are expected to arise among the PAH samples as a function of molecular size and structure will only show after the longer irradiation fluences that are expected in the exposure experiment on the ISS. (c) 2006 Elsevier Ltd. All rights reserved. C1 Leiden Univ, Leiden Inst Chem, Astrobiol Lab, NL-2300 RA Leiden, Netherlands. European Space Agcy, Res & Sci Support Dept, NL-2200 AG Noordwijk, Netherlands. NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA. RP Ehrenfreund, P (reprint author), Leiden Univ, Leiden Inst Chem, Astrobiol Lab, POB 9502, NL-2300 RA Leiden, Netherlands. EM p.ehrenfreund@chem.leidenuniv.nl RI Salama, Farid/A-8787-2009; Martins, Zita/H-4860-2015 OI Salama, Farid/0000-0002-6064-4401; Martins, Zita/0000-0002-5420-1081 NR 32 TC 21 Z9 21 U1 0 U2 6 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0032-0633 J9 PLANET SPACE SCI JI Planet Space Sci. PD MAR PY 2007 VL 55 IS 4 BP 383 EP 400 DI 10.1016/j.pss.2006.07.001 PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 147DW UT WOS:000244984600001 ER PT J AU Lee, J He, K Stolc, V Lee, H Figueroa, P Gao, Y Tongprasit, W Zhao, HY Lee, I Deng, X AF Lee, Jungeun He, Kun Stolc, Viktor Lee, Horim Figueroa, Pablo Gao, Ying Tongprasit, Waraporn Zhao, Hongyu Lee, Ilha Deng, XingWang TI Analysis of transcription factor HY5 genomic binding sites revealed its hierarchical role in light regulation of development SO PLANT CELL LA English DT Article ID MEDIATED PHOTOMORPHOGENIC GROWTH; GENE-EXPRESSION; CHROMATIN-IMMUNOPRECIPITATION; ARABIDOPSIS-THALIANA; PHENYLPROPANOID BIOSYNTHESIS; MICROARRAY EXPERIMENTS; SIGNAL-TRANSDUCTION; CIRCADIAN CLOCK; BZIP PROTEIN; CHIP-CHIP AB The transcription factor LONG HYPOCOTYL5 (HY5) acts downstream of multiple families of the photoreceptors and promotes photomorphogenesis. Although it is well accepted that HY5 acts to regulate target gene expression, in vivo binding of HY5 to any of its target gene promoters has yet to be demonstrated. Here, we used a chromatin immunoprecipitation procedure to verify suspected in vivo HY5 binding sites. We demonstrated that in vivo association of HY5 with promoter targets is not altered under distinct light qualities or during light-to-dark transition. Coupled with DNA chip hybridization using a high-density 60-nucleotide oligomer microarray that contains one probe for every 500 nucleotides over the entire Arabidopsis thaliana genome, we mapped genome-wide in vivo HY5 binding sites. This analysis showed that HY5 binds preferentially to promoter regions in vivo and revealed > 3000 chromosomal sites as putative HY5 binding targets. HY5 binding targets tend to be enriched in the early light-responsive genes and transcription factor genes. Our data thus support a model in which HY5 is a high hierarchical regulator of the transcriptional cascades for photomorphogenesis. C1 Yale Univ, Dept Mol Cellular & Dev Biol, New Haven, CT 06520 USA. Seoul Natl Univ, Dept Biol Sci, Seoul 151742, South Korea. Peking Univ, Ctr Bioinformat, Peking Yale Joint Ctr Plant Mol Genet & Agrobiote, Natl Lab Prot Engn & Plant Genet Engn, Beijing 100871, Peoples R China. Peking Univ, Coll Life Sci, Beijing 100871, Peoples R China. NASA, Ames Res Ctr, Genome Res Facil, Moffett Field, CA 94035 USA. Eloret Corp, Sunnyvale, CA 94087 USA. Yale Univ, Sch Med, Dept Epidemiol & Publ Hlth, New Haven, CT 06520 USA. RP Deng, X (reprint author), Yale Univ, Dept Mol Cellular & Dev Biol, New Haven, CT 06520 USA. EM xingwang.deng@yale.edu RI He, Kun/H-3617-2011; He, Kun/F-6322-2012; OI Figueroa, Pablo/0000-0002-1918-5493 FU NIGMS NIH HHS [GM-47850, R01 GM047850, R37 GM047850] NR 62 TC 326 Z9 355 U1 11 U2 61 PU AMER SOC PLANT BIOLOGISTS PI ROCKVILLE PA 15501 MONONA DRIVE, ROCKVILLE, MD 20855 USA SN 1040-4651 J9 PLANT CELL JI Plant Cell PD MAR PY 2007 VL 19 IS 3 BP 731 EP 749 DI 10.1105/tpc.106.047688 PG 19 WC Biochemistry & Molecular Biology; Plant Sciences; Cell Biology SC Biochemistry & Molecular Biology; Plant Sciences; Cell Biology GA 163BD UT WOS:000246132600004 PM 17337630 ER PT J AU Mahmoud, MA Parker, PA Woodall, WH Hawkins, DM AF Mahmoud, Mahmoud A. Parker, Peter A. Woodall, William H. Hawkins, Douglas M. TI A change point method for linear profile data SO QUALITY AND RELIABILITY ENGINEERING INTERNATIONAL LA English DT Article DE calibration; functional data; likelihood ratio; panel data; segmented regression; simple linear regression; statistical process control ID LIKELIHOOD RATIO TEST; 2 SEPARATE REGIMES; UNKNOWN TIMES; REGRESSION MODELS; PARAMETER CHANGES; CONTROL CHARTS; CURVES; TESTS; RESIDUALS AB We propose a change point approach based on the segmented regression technique for testing the constancy of the regression parameters in a linear profile data set. Each sample collected over time in the historical data set consists of several bivariate observations for which a simple linear regression model is appropriate. The change point approach is based on the likelihood ratio test for a change in one or more regression parameters. We compare the performance of this method to that of the most effective Phase I linear profile control chart approaches using a simulation study. The advantages of the change point method over the existing methods are greatly improved detection of sustained step changes in the process parameters and improved diagnostic tools to determine the sources of profile variation and the location(s) of the change point(s). Also, we give an approximation for appropriate thresholds for the test statistic. The use of the change point method is demonstrated using a data set from a calibration application at the National Aeronautics and Space Administration (NASA) Langley Research Center. Copyright (C) 2006 John Wiley & Sons, Ltd. C1 Cairo Univ, Fac Econ & Polit Sci, Dept Stat, Cairo, Egypt. NASA, Langley Res Ctr, Hampton, VA 23681 USA. Virginia Tech, Blacksburg, VA 24061 USA. Univ Minnesota, Minneapolis, MN 55455 USA. RP Mahmoud, MA (reprint author), Cairo Univ, Fac Econ & Polit Sci, Dept Stat, Cairo, Egypt. EM mamahmou@vt.edu RI Woodall, William/A-8094-2009 NR 49 TC 132 Z9 136 U1 1 U2 10 PU JOHN WILEY & SONS LTD PI CHICHESTER PA THE ATRIUM, SOUTHERN GATE, CHICHESTER PO19 8SQ, W SUSSEX, ENGLAND SN 0748-8017 J9 QUAL RELIAB ENG INT JI Qual. Reliab. Eng. Int. PD MAR PY 2007 VL 23 IS 2 BP 247 EP 268 DI 10.1002/qre.788 PG 22 WC Engineering, Multidisciplinary; Engineering, Industrial; Operations Research & Management Science SC Engineering; Operations Research & Management Science GA 146GY UT WOS:000244923700008 ER PT J AU Xing, LD Meshkat, L Donohue, SK AF Xing, Liudong Meshkat, Leila Donohue, Susan K. TI Reliability analysis of hierarchical computer-based systems subject to common-cause failures SO RELIABILITY ENGINEERING & SYSTEM SAFETY LA English DT Article; Proceedings Paper CT 4th International Conference on Quality and Reliability (ICQR 2005) CY AUG 09-11, 2005 CL Beijing, PEOPLES R CHINA SP Beijing Inst Technol, Hong Kong Polytech Univ, Dept Ind & Syst Engn, Natl Univ Singapore, Dept Ind & Syst Engn, Natl Nat Sci Fdn China, Beijing Key Program, KC Wong Educ Fdn, Beijing Sci Assoc, Key Program DE common-cause failures; dynamic fault trees; hierarchical systems; reliability analysis ID MODEL; PROBABILITIES; COVERAGE AB The results from reliability modeling and analysis are key contributors to design and tuning activities for computer-based systems. Each architecture style, however, poses different challenges for which analytical approaches must be developed or modified. The challenge we address in this paper is the reliability analysis of hierarchical computer-based systems (HS) with common-cause failures (CCF). The dependencies among components introduced by CCF complicate the reliability analysis of HS, especially when components affected by a common cause exist on different hierarchical levels. We propose an efficient decomposition and aggregation (EDA) approach for incorporating CCF into the reliability evaluation of HS. Our approach is to decompose an original HS reliability analysis problem with CCF into a number of reduced reliability problems freed from the CCF concerns. The approach is represented in a dynamic fault tree by a proposed CCF gate modeled after the functional dependency gate. We present the basics of the EDA approach by working through a hypothetical analysis of a HS subject to CCF and show how it can be extended to an analysis of a hierarchical phased-mission system subject to different CCF depending on mission phases. (c) 2006 Elsevier Ltd. All rights reserved. C1 Univ Massachusetts, Dept Elect & Comp Engn, N Dartmouth, MA 02747 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Virginia, Dept Syst & Informat Engn, Charlottesville, VA 22904 USA. RP Xing, LD (reprint author), Univ Massachusetts, Dept Elect & Comp Engn, 285 Old Westport Rd, N Dartmouth, MA 02747 USA. EM lxing@umassd.edu; Leila.Meshkat@jpl.nasa.gov; SusanD@virginia.edu NR 22 TC 19 Z9 25 U1 0 U2 10 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0951-8320 J9 RELIAB ENG SYST SAFE JI Reliab. Eng. Syst. Saf. PD MAR PY 2007 VL 92 IS 3 BP 351 EP 359 DI 10.1016/j.ress.2006.04.010 PG 9 WC Engineering, Industrial; Operations Research & Management Science SC Engineering; Operations Research & Management Science GA 123HM UT WOS:000243287000011 ER PT J AU Mays, ML St Cyr, OC Quemerais, E Ferron, S Bertaux, JL Yashiro, S Howard, R AF Mays, M. L. St Cyr, O. C. Quemerais, E. Ferron, S. Bertaux, J. -L. Yashiro, S. Howard, R. TI An attempt to detect coronal mass ejections in Lyman-alpha using SOHOSWAN SO SOLAR PHYSICS LA English DT Article ID SOLAR-WIND; LASCO; SWAN; SPACECRAFT; COMETS; SMEI AB In this study, the possibility that coronal mass ejections (CMEs) may be observed in neutral Lyman-alpha emission was investigated. An observing campaign was initiated for SWAN (Solar Wind ANisotropies), a Lyman-alpha scanning photometer on board the Solar and Heliospheric Observatory (SOHO) dedicated to monitoring the latitude distribution of the solar wind from its imprints on the interstellar sky background. This was part of SOHO Joint Observing Program (JOP) 159 and was an exploratory investigation as it was not known how, or even if, CMEs interact with the solar wind and interstellar neutral hydrogen at this distance (approximate to 60 and 120 R (S)). The study addresses the lack of methods for tracking CMEs beyond the field-of-view of current coronagraphs (30 R (S)). In our first method we used LASCO, white-light coronagraphs on SOHO, and EIT, an extreme ultraviolet imaging telescope also on SOHO, to identify CME candidates which, subject to certain criteria, should have been observable in SWAN. The criteria included SWAN observation time and location, CME position angle, and extrapolated speed. None of the CME candidates that we discuss were identified in the SWAN data. For our second method we analyzed all of the SWAN data for 184 runs of the observing campaign, and this has yielded one candidate CME detection. The candidate CME appears as a dimming of the background Lyman-alpha intensity representing approximate to 10% of the original intensity, moving radially away from the Sun. Multiple candidate CMEs observed by LASCO and EIT were found which may have caused this dimming. Here we discuss the campaign, data analysis technique and statistics, and the results. C1 Univ Texas, Dept Phys, Austin, TX 78712 USA. NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. CNRS, Serv Aeron, F-91371 Verrieres Le Buisson, France. Catholic Univ Amer, Washington, DC 20064 USA. USN, Res Lab, Washington, DC 20375 USA. RP Mays, ML (reprint author), Univ Texas, Dept Phys, 1 Univ Stn C1600, Austin, TX 78712 USA. EM lmays@physics.utexas.edu NR 18 TC 1 Z9 1 U1 0 U2 1 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-0938 J9 SOL PHYS JI Sol. Phys. PD MAR PY 2007 VL 241 IS 1 BP 113 EP 125 DI 10.1007/s11207-007-0196-8 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 154JM UT WOS:000245503000011 ER PT J AU Chernov, GP Kaiser, ML Bougeret, JL Fomichev, VV Gorgutsa, RV AF Chernov, G. P. Kaiser, M. L. Bougeret, J. -L. Fomichev, V. V. Gorgutsa, R. V. TI Fine structure of solar radio bursts observed at decametric and hectometric waves SO SOLAR PHYSICS LA English DT Article DE Sun; flare; radio emission; fine structure ID INTERMEDIATE DRIFT BURSTS; ZEBRA-PATTERN; 1 AU; EMISSION; CORONA; RADIATION; GENERATION; WHISTLERS; WAVELENGTHS; INSTABILITY AB The analysis of WIND/WAVES RAD2 spectra with fine structure in the form of different fibers in 14 events covering 1997 - 2005 is carried out. A splitting of broad bands of the interplanetary (IP) type II bursts into narrow band fibers of different duration is observed. The instantaneous-frequency bandwidth of fibers is stable: 200 - 300 kHz for slow-drifting fibers in type II bursts, and 700 - 1000 kHz for fast-drifting fibers in type II+IV ( continuum). Intermediate drift bursts (IDB or fiber bursts) and zebra patterns with variable frequency drift of stripes, typical for the metric range, were not found. Comparison of spectra with the Solar and Heliospheric Observatory/Large Angle and Spectrometric Coronagraph (SOHO/LASCO C2) images shows a connection of the generation of the fiber structures with the passage of shock fronts through narrow jets in the wake of Coronal Mass Ejections (CME). Therefore the most probable emission mechanism of fibers in IP type II bursts appears to be resonance transition radiation (RTR) of fast particles at the boundary of two media with different refractive indices. The same mechanism is also valid for striae in the type III bursts. Taking into account a high-density contrast in the CME wake and the actually observed small-scale inhomogeneities, the effectiveness of the RTR mechanism in IP space must be considerably higher than in the meter or decimeter wavelengths. For the most part the fibers in the type IV continuum at frequencies of 14 - 8 MHz were seen as the direct expansion of similar fine structure ( as fibers or "herringbone" structure) in the decametric range observed with the Nancay and IZMIRAN spectrographs. C1 IZMIRAN, Troitsk 142190, Moscow Region, Russia. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Observ Paris, CNRS, LESIA, F-92195 Meudon, France. RP Chernov, GP (reprint author), IZMIRAN, Troitsk 142190, Moscow Region, Russia. EM gchernov@izmiran.rssi.ru NR 32 TC 13 Z9 13 U1 0 U2 1 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-0938 J9 SOL PHYS JI Sol. Phys. PD MAR PY 2007 VL 241 IS 1 BP 145 EP 169 DI 10.1007/s11207-007-0258-y PG 25 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 154JM UT WOS:000245503000013 ER PT J AU Fishbaugh, KE Marais, DJD Korablev, O Lognonne, P Raulin, F AF Fishbaugh, Kathryn E. Marais, David J. Des Korablev, Oleg Lognonne, Philippe Raulin, Francois TI Introduction: A multidisciplinary approach to habitability SO SPACE SCIENCE REVIEWS LA English DT Editorial Material ID PLANETS; OBLIQUITY; EARTH; MARS C1 Int Space Sci Inst, CH-3012 Bern, Switzerland. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Russian Space Res Inst, Moscow 117997, Russia. Univ Paris 07, Equipe Etudies Spatiales & Planetol, F-94107 St Maur des Fosses, France. Univ Paris 12, CNRS, UMR, Lab Interuniv Syst Atmospher, F-94010 Creteil, France. Univ Paris 07, CNRS, UMR, Lab Interuniv Syst Atmospher, F-94010 Creteil, France. RP Fishbaugh, KE (reprint author), Int Space Sci Inst, Hallerstr 6, CH-3012 Bern, Switzerland. EM kathryn.fishbaugh@issibern.ch RI Lognonne, Philippe/F-8846-2010; Korablev, Oleg/L-5083-2013 NR 17 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-6308 J9 SPACE SCI REV JI Space Sci. Rev. PD MAR PY 2007 VL 129 IS 1-3 BP 1 EP 5 DI 10.1007/s11214-007-9208-0 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 202MT UT WOS:000248906500001 ER PT J AU Southam, G Rothschild, LJ Westall, F AF Southam, G. Rothschild, L. J. Westall, F. TI The geology and habitability of terrestrial planets: Fundamental requirements for life SO SPACE SCIENCE REVIEWS LA English DT Review DE origin of life; extremophiles; earth; life requirements ID BARBERTON GREENSTONE-BELT; SULFATE-REDUCING BACTERIA; SOUTHERN WEST GREENLAND; ISUA SUPRACRUSTAL BELT; FLOOR HYDROTHERMAL VENTS; EARTHS EARLY ATMOSPHERE; PROTON MOTIVE FORCE; EARLY ARCHEAN ERA; NORTH-POLE AREA; ART. NO. 5022 AB The current approach to the study of the origin of life and to the search for life elsewhere is based on two assumptions. First, life is a purely physical phenomenon closely linked to specific environmental conditions. From this, we hypothesise that when these environmental conditions are met, life will arise and evolve. If these assumptions are valid, the search for life elsewhere should be a matter of mapping what we know about the range of environments in which life can exist, and then simply trying to find these environments elsewhere. Second, life can be clearly distinguished from the non-living world. While a single feature of a living organism left in the rock record is not always sufficient to determine unequivocally whether life was present, life often leaves multiple structural, mineralogical and chemical biomarkers that, in sum, support a conclusion that life was present. Our understanding of the habitats that can sustain or have sustained life has grown tremendously with the characterisation of extremophiles. In this chapter, we highlight the range of environments that are known to harbour life on Earth, describe the environments that existed during the period of time when life originated on Earth, and compare these habitats to the suitable environments that are found elsewhere in our solar system, where life could have arisen and evolved. C1 Univ Western Ontario, Dept Earth Sci, London, ON N6A 5B7, Canada. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. CNRS, Ctr Biophys Mol, F-45071 Orleans 2, France. RP Southam, G (reprint author), Univ Western Ontario, Dept Earth Sci, London, ON N6A 5B7, Canada. EM gsoutham@uwo.ca RI Southam, Gordon/D-1983-2013 OI Southam, Gordon/0000-0002-8941-1249 NR 272 TC 10 Z9 10 U1 5 U2 34 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-6308 EI 1572-9672 J9 SPACE SCI REV JI Space Sci. Rev. PD MAR PY 2007 VL 129 IS 1-3 BP 7 EP 34 DI 10.1007/s11214-007-9148-8 PG 28 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 202MT UT WOS:000248906500002 ER PT J AU Zahnle, K Arndt, N Cockell, CS Halliday, A Nisbet, E Selsis, F Sleep, NH AF Zahnle, Kevin Arndt, Nick Cockell, Charles S. Halliday, Alex Nisbet, Euan Selsis, Franck Sleep, Norman H. TI Emergence of a habitable planet SO SPACE SCIENCE REVIEWS LA English DT Review DE hadean earth; moon-forming impact; origin of earth; magma oceans; planetary atmospheres; late heavy bombardment ID LATE HEAVY BOMBARDMENT; INNER SOLAR-SYSTEM; HF-W CHRONOMETRY; PRIMORDIAL TERRESTRIAL ATMOSPHERE; EARLY CORE FORMATION; EARTH-MOON SYSTEM; FRONT FACE BASINS; CONTINENTAL-CRUST; ISOTOPE SYSTEMATICS; DETRITAL ZIRCONS AB We address the first several hundred million years of Earth's history. The Moon-forming impact left Earth enveloped in a hot silicate atmosphere that cooled and condensed over similar to 1,000 yrs. As it cooled the Earth degassed its volatiles into the atmosphere. It took another similar to 2 Myrs for the magma ocean to freeze at the surface. The cooling rate was determined by atmospheric thermal blanketing. Tidal heating by the new Moon was a major energy source to the magma ocean. After the mantle solidified geothermal heat became climatologically insignificant, which allowed the steam atmosphere to condense, and left behind a similar to 100 bar, similar to 500 K CO2 atmosphere. Thereafter cooling was governed by how quickly CO2 was removed from the atmosphere. If subduction were efficient this could have taken as little as 10 million years. In this case the faint young Sun suggests that a lifeless Earth should have been cold and its oceans white with ice. But if carbonate subduction were inefficient the CO2 would have mostly stayed in the atmosphere, which would have kept the surface near similar to 500 K for many tens of millions of years. Hydrous minerals are harder to subduct than carbonates and there is a good chance that the Hadean mantle was dry. Hadean heat flow was locally high enough to ensure that any ice cover would have been thin (< 5 m) in places. Moreover hundreds or thousands of asteroid impacts would have been big enough to melt the ice triggering brief impact summers. We suggest that plate tectonics as it works now was inadequate to handle typical Hadean heat flows of 0.2-0.5 W/m(2). In its place we hypothesize a convecting mantle capped by a similar to 100 km deep basaltic mush that was relatively permeable to heat flow. Recycling and distillation of hydrous basalts produced granitic rocks very early, which is consistent with preserved > 4 Ga detrital zircons. If carbonates in oceanic crust subducted as quickly as they formed, Earth could have been habitable as early as 10-20 Myrs after the Moon-forming impact. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ Grenoble 1, LGCA, F-38401 Grenoble, France. Open Univ, Planetary & Space Sci Res Inst, Milton Keynes MK7 6AA, Bucks, England. Univ Oxford, Dept Earth Sci, Oxford OX1 3PR, England. Univ London, Royal Holloway & Bedford New Coll, Dept Geol, Egham TW20 0EX, Surrey, England. Ecole Normale Super Lyon, Ctr Rech Astron Lyon, F-69364 Lyon 07, France. Univ Lyon 1, CNRS, UMR 5574, F-69365 Lyon, France. Stanford Univ, Dept Geophys, Stanford, CA 94305 USA. RP Zahnle, K (reprint author), NASA, Ames Res Ctr, MS 245-3, Moffett Field, CA 94035 USA. EM Kevin.J.Zahnle@nasa.gov RI Korablev, Oleg/L-5083-2013 NR 219 TC 122 Z9 127 U1 14 U2 69 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-6308 EI 1572-9672 J9 SPACE SCI REV JI Space Sci. Rev. PD MAR PY 2007 VL 129 IS 1-3 BP 35 EP 78 DI 10.1007/s11214-007-9225-z PG 44 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 202MT UT WOS:000248906500003 ER PT J AU Nisbet, E Zahnle, K Gerasimov, MV Helbert, J Jaumann, R Hofmann, BA Benzerara, K Westall, F AF Nisbet, Euan Zahnle, Kevin Gerasimov, M. V. Helbert, Joern Jaumann, Ralf Hofmann, Beda A. Benzerara, Karim Westall, Frances TI Creating habitable zones, at all scales, from planets to mud micro-habitats, on earth and on mars SO SPACE SCIENCE REVIEWS LA English DT Review DE mars; water; fluvial erosion; habitable surfaces; rock cycle ID X-RAY SPECTROMETER; PATHFINDER LANDING SITE; BARBERTON MOUNTAIN LAND; PLATE-TECTONICS; CHEMICAL-COMPOSITION; OMEGA/MARS EXPRESS; WESTERN-AUSTRALIA; MERIDIANI-PLANUM; SOUTH-AFRICA; GUSEV CRATER AB The factors that create a habitable planet are considered at all scales, from planetary inventories to micro-habitats in soft sediments and intangibles such as habitat linkage. The possibility of habitability first comes about during accretion, as a product of the processes of impact and volatile inventory history. To create habitability water is essential, not only for life but to aid the continual tectonic reworking and erosion that supply key redox contrasts and biochemical substrates to sustain habitability. Mud or soft sediment may be a biochemical prerequisite, to provide accessible substrate and protection. Once life begins, the habitat is widened by the activity of life, both by its management of the greenhouse and by partitioning reductants (e.g. dead organic matter) and oxidants (including waste products). Potential Martian habitats are discussed: by comparison with Earth there are many potential environmental settings on Mars in which life may once have occurred, or may even continue to exist. The long-term evolution of habitability in the Solar System is considered. C1 Univ London, Royal Holloway & Bedford New Coll, Dept Geol, Egham TW20 0EX, Surrey, England. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Russian Acad Sci, Inst Space Res, Moscow 117997, Russia. DLR, Inst Planetary Res, D-12489 Berlin, Germany. Nat Hist Museum Bern, CH-3005 Bern, Switzerland. Inst Mineral & Phys Milieux Condenses, CNRS, UMR 7590, F-75015 Paris, France. IPGP, F-75015 Paris, France. CNRS, Ctr Biophys Mol, F-45071 Orleans 2, France. RP Nisbet, E (reprint author), Univ London, Royal Holloway & Bedford New Coll, Dept Geol, Egham TW20 0EX, Surrey, England. EM e.nisbet@gl.rhul.ac.uk; kzahnle@mail.arc.nasa.gov; mgerasim@mx.iki.rssi.ru RI Benzerara, Karim/J-1532-2016; IMPMC, Geobio/F-8819-2016 OI Benzerara, Karim/0000-0002-0553-0137; NR 197 TC 13 Z9 13 U1 3 U2 12 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-6308 EI 1572-9672 J9 SPACE SCI REV JI Space Sci. Rev. PD MAR PY 2007 VL 129 IS 1-3 BP 79 EP 121 DI 10.1007/s11214-007-9175-5 PG 43 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 202MT UT WOS:000248906500004 ER PT J AU Bertaux, JL Carr, M Des Marais, DJ Gaidos, E AF Bertaux, J.-L. Carr, M. Des Marais, D. J. Gaidos, E. TI Conversations on the habitability of worlds: The importance of volatiles SO SPACE SCIENCE REVIEWS LA English DT Review DE origin of life; habitability; planetary volatiles; mars; biogeochemical cycles; planetary atmospheres; biological evolution ID ATMOSPHERIC CARBON-DIOXIDE; MARTIAN NORTHERN PLAINS; EARTHS EARLY ATMOSPHERE; EARLY MARS; MERIDIANI-PLANUM; SNC METEORITES; CLIMATE-CHANGE; SULFUR CYCLE; GROUND ICE; PLANETARY-ATMOSPHERES AB Our scientific forefathers discuss the interrelationships between water, climate, the atmosphere, and life on Earth and other terrestrial planets at a workshop in Nichtchaotel, Switzerland. C1 Univ Hawaii, Honolulu, HI 96822 USA. CNRS, Serv Aeron, Paris, France. USGS, Menlo Pk, CA USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Gaidos, E (reprint author), Univ Hawaii, Honolulu, HI 96822 USA. EM jean-loup.bertaux@aerovre.jussieu.fr; carr@usgs.gov; david.j.desmarais@nasa.gov; gaidos@hawaii.edu NR 209 TC 3 Z9 3 U1 1 U2 4 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-6308 EI 1572-9672 J9 SPACE SCI REV JI Space Sci. Rev. PD MAR PY 2007 VL 129 IS 1-3 BP 123 EP 165 DI 10.1007/s11214-007-9193-3 PG 43 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 202MT UT WOS:000248906500005 ER PT J AU Chen, SS Fitzgerald, W Zimmerberg, J Kleinman, HK Margolis, L AF Chen, Silvia S. Fitzgerald, Wendy Zimmerberg, Joshua Kleinman, Hynda K. Margolis, Leonid TI Cell-cell and cell-extracellular matrix interactions regulate embryonic stem cell differentiation SO STEM CELLS LA English DT Article DE embryonic stem cell biology; rhesus; real-time reverse transcription-polymerase chain reaction; lineage analysis ID TERATOCARCINOMA CELLS; IN-VITRO; COLLAGEN; LAMININ; GROWTH; CARDIOMYOCYTES; PROLIFERATION; EXPRESSION; LIVER; SHAPE AB Cell interactions with the extracellular matrix (ECM) play a critical role in their physiology. Here, we sought to determine the role of exogenous and endogenous ECM in the differentiation of nonhuman primate ESCs. We evaluated cell differentiation from expression of lineage gene mRNA and proteins using real-time polymerase chain reaction and immunohistochemistry. We found that ESCs that attached to and spread upon highly adhesive collagen do not differentiate efficiently, whereas on the less adhesive Matrigel, ESCs form aggregates and differentiate along mesoderm and especially endoderm. lineages. To further decrease ESC attachment to the substrate, we cultured them either on nonadhesive agarose or in suspension. In both cases, ESCs formed aggregates and efficiently differentiated along endoderm and mesoderm lineages, most strikingly into cardiomyocytes. Aggregates formed by thus-differentiated ESCs started to beat with a frequency of 50-100 beats per minute and continued to beat for approximately a month. In spite of the presence of exogenous ECM, ESCs were dependent on endogenous ECM for their survival and differentiation, as the inhibition of endogenous collagen induced a gradual loss of ESCs and neither a simple matrix, such as type I collagen, nor the complex matrix Matrigel was able to rescue these cells. In conclusion, adhesiveness to various ECM and nonbiological substrates determines the differentiation of ESCs in such a way that efficient cell-cell aggregation, together with less efficient cell attachment and spreading, results in more efficient cell differentiation. C1 NIDCR, NIH, Lab Cellular & Mol Biophys, Bethesda, MD 20892 USA. NIDCR, NIH, NASA, NICHHD,Ctr Tissue Culture Dimens 3, Bethesda, MD 20892 USA. NIDCR, NIH, Cell Biol Sect, Bethesda, MD 20892 USA. RP Kleinman, HK (reprint author), NIDCR, NIH, Lab Cellular & Mol Biophys, 30 Convent Dr,Bldg 30,Room 407, Bethesda, MD 20892 USA. EM hkleinman@dir.nidcr.nih.gov; margolil@mail.nih.gov FU Intramural NIH HHS NR 29 TC 100 Z9 107 U1 1 U2 11 PU ALPHAMED PRESS PI DURHAM PA 318 BLACKWELL ST, STE 260, DURHAM, NC 27701-2884 USA SN 1066-5099 J9 STEM CELLS JI Stem Cells PD MAR PY 2007 VL 25 IS 3 BP 553 EP 561 DI 10.1634/stemcells.2006-0419 PG 9 WC Cell & Tissue Engineering; Biotechnology & Applied Microbiology; Oncology; Cell Biology; Hematology SC Cell Biology; Biotechnology & Applied Microbiology; Oncology; Hematology GA 145EC UT WOS:000244847100002 PM 17332514 ER PT J AU Ukita, J Honda, M Nakamura, H Tachibana, Y Cavalieri, DJ Parkinson, CL Koide, H Yamamoto, K AF Ukita, Jinro Honda, Meiji Nakamura, Hisashi Tachibana, Yoshihiro Cavalieri, Donald J. Parkinson, Claire L. Koide, Hiroshi Yamamoto, Kentaro TI Northern Hemisphere sea ice variability: lag structure and its implications SO TELLUS SERIES A-DYNAMIC METEOROLOGY AND OCEANOGRAPHY LA English DT Article ID WINTER ATMOSPHERIC CIRCULATION; SURFACE TEMPERATURE ANOMALIES; NINO-SOUTHERN OSCILLATION; ATLANTIC CLIMATE-CHANGE; GEOPOTENTIAL HEIGHT; LEVEL PRESSURE; HIGH-LATITUDES; FRESH-WATER; COVER; TRENDS AB An analysis of satellite sea-ice records for recent decades reveals a highly coherent spatial and temporal structure of the Northern Hemisphere (NH) wintertime sea-ice variability and its close link to anomalous atmospheric circulation. The dominant mode of the wintertime sea-ice variability is characterized by a double-dipole composed of one dipole over the North Atlantic and the other over the North Pacific, which are mutually correlated interannually. This dominant sea-ice mode is lag correlated with the winter-averaged North Atlantic Oscillation (NAO) index at lags up to two winters when the NAO leads. In the sub-Arctic, significant lead-lag relationships exist between sea-ice extent (SIE) anomalies on regional scales, which are closely associated with atmospheric circulation anomalies. An eastward evolving pattern is identified in regional SIE anomalies from the Labrador to Nordic and farther to the Okhotsk Sea at multi-year time-scales, led by anomalously weak Aleutian and strong Icelandic lows. The results suggest the presence of climate memories over the North Atlantic and Eurasia, which are crucial for recent downward trends in the NH SIE by transforming atmospheric influences into slower changes in sea-ice conditions. The summer Okhotsk high, which leads to a sea-ice reduction along the east Siberian coast and further affects sea-ice conditions over the Arctic Ocean, is a key link between summer Arctic and winter sub-Arctic sea-ice trends. We also conjecture that variations and changes in the NH sea-ice conditions are linked to climate variability in the tropics. C1 Columbia Univ, Palisades, NY 10964 USA. Japan Agcy Marine, Earth Sci & Technol Ctr, Frontier Res Ctr Global Change, Yokohama, Kanagawa 236, Japan. Int Res Inst Climate Predict, Palisades, NY 10964 USA. Univ Tokyo, Dept Earth & Planetary Sci, Tokyo 113, Japan. Tokai Univ, Liberal Arts Educ Ctr, Hiratsuka, Kanagawa 25912, Japan. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Japan Meteorol Agcy, Tokyo 100, Japan. RP Ukita, J (reprint author), Chiba Univ, Ctr Environm Remote Sensing, 1-33 Yayoi, Chiba 2638522, Japan. EM jukita@faculty.chiba-u.jp RI Parkinson, Claire/E-1747-2012 OI Parkinson, Claire/0000-0001-6730-4197 NR 57 TC 25 Z9 25 U1 1 U2 6 PU CO-ACTION PUBLISHING PI JARFALLA PA RIPVAGEN 7, JARFALLA, SE-175 64, SWEDEN SN 0280-6495 EI 1600-0870 J9 TELLUS A JI Tellus Ser. A-Dyn. Meteorol. Oceanol. PD MAR PY 2007 VL 59 IS 2 BP 261 EP 272 DI 10.1111/j.1600-0870.2006.00223.x PG 12 WC Meteorology & Atmospheric Sciences; Oceanography SC Meteorology & Atmospheric Sciences; Oceanography GA 140QO UT WOS:000244520900009 ER PT J AU Errico, RM AF Errico, Ronald M. TI Interpretations of an adjoint-derived observational impact measure SO TELLUS SERIES A-DYNAMIC METEOROLOGY AND OCEANOGRAPHY LA English DT Letter AB The measure developed by Langland and Baker to estimate and compare the utility of arbitrary sets of observations for reducing forecast error is re-derived here. The formula uses adjoints of both a forecast model and a data assimilation system. Although the final expression here is nearly identical to that developed by Langland and Baker, the third-order character of their measure is now explicitly presented. The appropriateness of going beyond first order is explained and a warning of the measure's nonlinearity possibly clouding its interpretation is offered. C1 Univ Maryland Baltimore Cty, Goddard Earth Sci & Technol Ctr, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Global Modeling & Assimilat Off, Greenbelt, MD 20771 USA. RP Errico, RM (reprint author), Univ Maryland Baltimore Cty, Goddard Earth Sci & Technol Ctr, Code 610-1, Greenbelt, MD 20771 USA. EM rerrico@gmao.gsfc.nasa.gov NR 2 TC 28 Z9 28 U1 1 U2 6 PU BLACKWELL PUBLISHING PI OXFORD PA 9600 GARSINGTON RD, OXFORD OX4 2DQ, OXON, ENGLAND SN 0280-6495 J9 TELLUS A JI Tellus Ser. A-Dyn. Meteorol. Oceanol. PD MAR PY 2007 VL 59 IS 2 BP 273 EP 276 DI 10.1111/j.1600-0870.2006.00217.x PG 4 WC Meteorology & Atmospheric Sciences; Oceanography SC Meteorology & Atmospheric Sciences; Oceanography GA 140QO UT WOS:000244520900010 ER PT J AU DellaCorte, C AF DellaCorte, Christopher TI Tribology marches ahead SO TRIBOLOGY & LUBRICATION TECHNOLOGY LA English DT Editorial Material C1 NASA, Glenn Res Ctr, Cleveland, OH USA. RP DellaCorte, C (reprint author), NASA, Glenn Res Ctr, Cleveland, OH USA. EM cdellacorte@stle.org NR 0 TC 0 Z9 0 U1 0 U2 0 PU SOC TRIBOLOGISTS & LUBRICATION ENGINEERS PI PARK RIDGE PA 840 BUSSE HIGHWAY, PARK RIDGE, IL 60068 USA SN 1545-858X J9 TRIBOL LUBR TECHNOL JI Tribol. Lubr. Technol. PD MAR PY 2007 VL 63 IS 3 BP 6 EP 6 PG 1 WC Engineering, Mechanical SC Engineering GA 147KB UT WOS:000245000800002 ER PT J AU Morscher, GN Singh, M Shpargel, T AF Morscher, Gregory N. Singh, Mrityunjay Shpargel, Tarah TI Comparison of braze and solder materials for joining titanium to composites SO WELDING JOURNAL LA English DT Editorial Material C1 Ohio Aerosp Inst NASA, Glenn Res Ctr, Cleveland, OH USA. NASA, Glenn Res Ctr, Cleveland, OH USA. RP Morscher, GN (reprint author), Ohio Aerosp Inst NASA, Glenn Res Ctr, Cleveland, OH USA. EM Gregory.N.Morscher@grc.nasa.gov NR 8 TC 1 Z9 1 U1 1 U2 1 PU AMER WELDING SOC PI MIAMI PA 550 N W LEJEUNE RD, MIAMI, FL 33126 USA SN 0043-2296 J9 WELD J JI Weld. J. PD MAR PY 2007 VL 86 IS 3 BP 62 EP 66 PG 5 WC Metallurgy & Metallurgical Engineering SC Metallurgy & Metallurgical Engineering GA 141BE UT WOS:000244550500012 ER PT J AU Kazil, J Lovejoy, ER Jensen, EJ Hanson, DR AF Kazil, J. Lovejoy, E. R. Jensen, E. J. Hanson, D. R. TI Is aerosol formation in cirrus clouds possible? SO ATMOSPHERIC CHEMISTRY AND PHYSICS LA English DT Article ID PARTICLE FORMATION; UPPER TROPOSPHERE; SULFUR-DIOXIDE; EXPERIMENTAL THERMODYNAMICS; STRATOSPHERIC AEROSOL; PACIFIC-OCEAN; MIDLATITUDES; NUCLEATION; H2SO4; NORTHERN AB The recent observation of ultrafine aerosol particles in cirrus clouds has raised the question whether aerosol formation within cirrus clouds is possible, and if so, what mechanisms are involved. We have developed an aerosol parcel model of neutral and charged H2SO4/H2O aerosol processes, including nucleation from the gas phase and loss onto cirrus ice particles. Laboratory thermodynamic data for sulfuric acid uptake and loss by small neutral and charged clusters are used, allowing for a reliable description of both neutral and charged nucleation down to the very low temperatures occurring in the upper troposphere and lower stratosphere. The model implements a first order scheme for resolving the aerosol size distribution within its geometric size sections, which efficiently suppresses numerical diffusion. We operate the model offline on trajectories generated with a detailed 1D cirrus model which describes ice crystal nucleation, deposition growth, vertical advection of ice crystals and water vapor, and ice crystal sedimentation. In this paper we explore the possibility of aerosol formation within non-convective cirrus clouds and draw conclusions for aerosol formation in anvil cirrus. We find that sulfate aerosol formation within cirrus clouds can proceed even at high ice surface area concentrations, and depends strongly on the size of the cirrus ice crystals and on the surface area concentration of preexisting aerosol particles. C1 NOAA, Earth Syst Res Lab, Boulder, CO 80303 USA. NRC Res Associateship Programs, Washington, DC USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Augsburg Coll, Minneapolis, MN USA. RP Kazil, J (reprint author), NOAA, Earth Syst Res Lab, Boulder, CO 80303 USA. EM jan.kazil@noaa.gov RI Kazil, Jan/B-7652-2013 OI Kazil, Jan/0000-0003-3271-2451 NR 30 TC 9 Z9 9 U1 0 U2 3 PU COPERNICUS GESELLSCHAFT MBH PI GOTTINGEN PA BAHNHOFSALLEE 1E, GOTTINGEN, 37081, GERMANY SN 1680-7316 EI 1680-7324 J9 ATMOS CHEM PHYS JI Atmos. Chem. Phys. PD FEB 28 PY 2007 VL 7 BP 1407 EP 1413 PG 7 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 143HY UT WOS:000244712500003 ER PT J AU Koetz, B Sun, GQ Morsdorf, F Ranson, KJ Kneubuhler, M Itten, K Allgower, B AF Koetz, Benjamin Sun, Guoqing Morsdorf, Felix Ranson, K. J. Kneubuehler, Mathias Itten, Klaus Allgoewer, Britta TI Fusion of imaging spectrometer and LIDAR data over combined radiative transfer models for forest canopy characterization SO REMOTE SENSING OF ENVIRONMENT LA English DT Article DE imaging spectrometer; LIDAR; radiative transfer model; LAI; fractional cover; tree height; canopy structure; biomass; forest; inversion; fusion; forest growth model ID REMOTE-SENSING DATA; LARGE-FOOTPRINT LIDAR; LASER ALTIMETER; THEORETICAL-ANALYSIS; TREE HEIGHT; WAVE-FORMS; SAIL MODEL; LEAF-AREA; VEGETATION; REFLECTANCE AB A comprehensive canopy characterization of forests is derived from the combined remote sensing signal of imaging spectrometry and large footprint LIDAR. The inversion of two linked physically based Radiative Transfer Models (RTM) provided the platform for synergistically exploiting the specific and independent information dimensions obtained by the two earth observation systems. Due to its measurement principle, LIght Detection And Ranging (LIDAR) is particularly suited to assess the horizontal and vertical canopy structure of forests, while the spectral measurements of imaging spectrometry are specifically rich on information for biophysical and -chemical canopy properties. In the presented approach, the specific information content inherent to the observations of the respective sensor was not only able to complement the canopy characterization, but also helped to solve the ill-posed problem of the RTM inversion. The theoretical feasibility of the proposed earth observation concept has been tested on a synthetic data set generated by a forest growth model for a wide range of forest stands. Robust estimates on forest canopy characteristics were achieved, ranging from maximal tree height, fractional cover (fcover), Leaf Area Index (LAI) to the foliage chlorophyll and water content. The introduction of prior information on the canopy structure derived from large footprint LIDAR observations significantly improved the retrieval performance relative to estimates based solely on spectral information. (c) 2006 Elsevier Inc. All rights reserved. C1 Univ Zurich, Dept Geog, RSL, CH-8057 Zurich, Switzerland. Univ Maryland, Dept Geog, College Pk, MD 20742 USA. NASA, Goddard Space Flight Ctr, Biospher Sci Branch, Greenbelt, MD 20771 USA. Univ Zurich, Dept Geog, Geog Informat Syst, CH-8006 Zurich, Switzerland. RP Koetz, B (reprint author), Univ Zurich, Dept Geog, RSL, Winterthurerstr 190, CH-8057 Zurich, Switzerland. EM bkoetz@geo.unizh.ch RI Kneubuehler, Mathias/D-1153-2010; Morsdorf, Felix/D-1151-2010; Ranson, Kenneth/G-2446-2012; Beckley, Matthew/D-4547-2013 OI Kneubuehler, Mathias/0000-0002-6716-585X; Ranson, Kenneth/0000-0003-3806-7270; NR 54 TC 54 Z9 56 U1 1 U2 30 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD FEB 28 PY 2007 VL 106 IS 4 BP 449 EP 459 DI 10.1016/j.rse.2006.09.013 PG 11 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA 138HH UT WOS:000244353200004 ER PT J AU Huang, CQ Kim, S Altstatt, A Townshend, JRG Davis, P Song, K Tucker, CJ Rodas, O Yanosky, A Clay, R Musinsky, J AF Huang, Chengquan Kim, Sunghee Altstatt, Alice Townshend, John R. G. Davis, Paul Song, Kuan Tucker, Compton J. Rodas, Oscar Yanosky, Alberto Clay, Rob Musinsky, John TI Rapid loss of Paraguay's Atlantic forest and the status of protected areas - A Landsat assessment SO REMOTE SENSING OF ENVIRONMENT LA English DT Article DE Atlantic forest; deforestation; Paraguay; protected area ID CONSERVATION AB Using Landsat images acquired since early 1970s, we have mapped the forest cover and change between 1989 and 2000, and estimated forest area in 1973 in Paraguay's Atlantic Forest Ecoregion (PAFE). The results revealed that as of 1973, 73.4% of the PAFE region was covered by forest. Since then, the proportion of forested area was quickly reduced to 40.7% by 1989 and further down to 24.9% by 2000. Two competing deforestation processes contributed to this rapid forest loss, with the first being driven by settlers and the second by large private land owners. During the 1989-2000 period, 80% of deforested areas were cleared by private land owners and 20% by the settlers. Protected areas slowed down forest loss within their boundaries, but not in their surrounding areas. The average percent forest loss in the area within 5 km from the boundary of Paraguay's major forested protected areas was 39% during the 1989-2000 period, which was essentially the same as that for the entire PAFE region during the same period. The high rates of forest loss in the areas surrounding the protected areas not only left the protected areas highly isolated as ecological "islands", they may also be precursors to rapid forest loss within the protected areas. These protected areas are critical to the conservation of many species endemic or limited to the PAFE region and surrounding areas, and should be continuously monitored using recent and future satellite observations. (c) 2006 Elsevier Inc. All rights reserved. C1 Univ Maryland, Dept Geog, College Pk, MD 20742 USA. Univ Maryland, Inst Adv Comp Studies, College Pk, MD 20742 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Guyra, Asuncion, Paraguay. Conservat Int, Washington, DC 20036 USA. RP Huang, CQ (reprint author), Univ Maryland, Dept Geog, 2181 LeFrak Hall, College Pk, MD 20742 USA. EM cqhuang@umd.edu OI Huang, Chengquan/0000-0003-0055-9798 NR 25 TC 59 Z9 62 U1 2 U2 29 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0034-4257 EI 1879-0704 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD FEB 28 PY 2007 VL 106 IS 4 BP 460 EP 466 DI 10.1016/j.rse.2006.09.016 PG 7 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA 138HH UT WOS:000244353200005 ER PT J AU Hanisco, TF Moyer, EJ Weinstock, EM St Clair, JM Sayres, DS Smith, JB Lockwood, R Anderson, JG Dessler, AE Keutsch, FN Spackman, JR Read, WG Bui, TP AF Hanisco, Thomas F. Moyer, E. J. Weinstock, E. M. St. Clair, J. M. Sayres, D. S. Smith, J. B. Lockwood, R. Anderson, J. G. Dessler, A. E. Keutsch, F. N. Spackman, J. R. Read, W. G. Bui, T. P. TI Observations of deep convective influence on stratospheric water vapor and its isotopic composition SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID TROPOSPHERE EXCHANGE; NASA ER-2; ART.; TRANSPORT; TROPOPAUSE; MIDLATITUDES; AIRCRAFT; PLUMES; RATIOS; SYSTEM AB In situ observations of H2O and HDO in the midlatitude stratosphere are used to evaluate the role of convection in determining the stratospheric water budget. The observations show that water vapor in the overworld stratosphere (potential temperature > 380 K) is isotopically heavier than expected. Measurements in an airmass with anomalously high concentrations of water vapor show isotopic water signatures that are characteristic of evaporated ice lofted from the troposphere during convective storms. Observed H2O and HDO concentrations in the plume of enhanced water and in the background stratosphere suggest that extratropical convection can account for a significant fraction of the observed water vapor in the summertime overworld stratosphere above the mid-North American continent. C1 Harvard Univ, Dept Chem & Biol Chem, Cambridge, MA 02138 USA. Texas A&M Univ, Dept Atmospher Sci, College Stn, TX 77843 USA. Univ Wisconsin, Dept Chem, Madison, WI 53706 USA. NOAA, Div Chem Sci, Earth Syst Res Lab, Boulder, CO 80305 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Hanisco, TF (reprint author), Harvard Univ, Dept Chem & Biol Chem, Cambridge, MA 02138 USA. EM hanisco@huarp.harvard.edu RI Keutsch, Frank/B-2391-2012; Dessler, Andrew/G-8852-2012 OI Dessler, Andrew/0000-0003-3939-4820 NR 29 TC 50 Z9 50 U1 3 U2 20 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 EI 1944-8007 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD FEB 27 PY 2007 VL 34 IS 4 AR L04814 DI 10.1029/2006GL027899 PG 5 WC Geosciences, Multidisciplinary SC Geology GA 143FY UT WOS:000244706600001 ER PT J AU Jackman, CH Roble, RG Fleming, EL AF Jackman, Charles H. Roble, Raymond G. Fleming, Eric L. TI Mesospheric dynamical changes induced by the solar proton events in October-November 2003 SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID 3-DIMENSIONAL MODEL SIMULATIONS; MIDDLE-ATMOSPHERE; JULY 13; OZONE; THERMOSPHERE; IONOSPHERE; OXYGEN AB The Thermosphere Ionosphere Mesosphere Electrodynamic General Circulation Model (TIME- GCM) was used to study the atmospheric dynamical influence of the solar protons that occurred in Oct-Nov 2003, the fourth largest period of solar proton events (SPEs) measured in the past 40 years. The highly energetic solar protons produced odd hydrogen (HOx) and odd nitrogen (NOy). Significant short- lived ozone decreases (10-70%) followed these enhancements of HOx and NOy and led to a cooling of most of the lower mesosphere. Temperature changes up to +/- 2.6 K were computed as well as wind (zonal, meridional, vertical) perturbations up to 20-25% of the background winds as a result of the solar protons. The solar proton-induced mesospheric temperature and wind perturbations diminished over a period of 4-6 weeks after the SPEs. The Joule heating in the mesosphere, induced by the solar protons, was computed to be relatively insignificant for these solar storms. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Natl Ctr Atmospher Res, High Altitude Observ, Boulder, CO 80307 USA. Sci Syst & Applicat Inc, Lanham, MD USA. RP Jackman, CH (reprint author), NASA, Goddard Space Flight Ctr, Code 613-3, Greenbelt, MD 20771 USA. EM charles.h.jackman@nasa.gov; roble@hao.ucar.edu; fleming@kahuna.gsfc.nasa.gov RI Jackman, Charles/D-4699-2012 NR 28 TC 23 Z9 23 U1 1 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 EI 1944-8007 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD FEB 27 PY 2007 VL 34 IS 4 AR L04812 DI 10.1029/2006GL028328 PG 5 WC Geosciences, Multidisciplinary SC Geology GA 143FY UT WOS:000244706600003 ER PT J AU Omidi, N Sibeck, DG AF Omidi, N. Sibeck, D. G. TI Flux transfer events in the cusp SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID DAYSIDE MAGNETOPAUSE; RECONNECTION AB We use 2.5-dimensional global hybrid (kinetic ions, fluid electrons) simulations to study the evolution of Flux Transfer Events (FTEs) and their interaction with the cusp during their poleward motion. A southward pointing interplanetary magnetic field is considered. It results in low-latitude, time-dependent reconnection and the formation of multiple FTEs with a variety of sizes ranging from a few hundred to thousands of km. FTEs are found to travel along the magnetopause surface with velocities exceeding the surrounding magnetosheath by similar to 1 local Alfven speed. As a result, a slow mode bow wave and a pile up of plasma and magnetic field precede larger, but not smaller, FTEs. As an FTE encounters the cusp, a secondary magnetic reconnection is initiated which ultimately leads to its disintegration as it moves to higher latitudes. Both the slow mode bow wave and reconnection accelerate plasma into the cusp and enhance the flux of energetic ions in this region. The downward flux of ions at a given energy moves poleward in time, exhibiting characteristics similar to the poleward moving auroral forms previously attributed to FTEs. C1 Solana Sci Inc, Solana Beach, CA 92075 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Omidi, N (reprint author), Solana Sci Inc, Suite 208B, Solana Beach, CA 92075 USA. EM omidi@solanasci.com RI Sibeck, David/D-4424-2012 NR 14 TC 21 Z9 22 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 EI 1944-8007 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD FEB 27 PY 2007 VL 34 IS 4 AR L04106 DI 10.1029/2006GL028698 PG 5 WC Geosciences, Multidisciplinary SC Geology GA 143FY UT WOS:000244706600006 ER PT J AU Kharche, N Prada, M Boykin, TB Klimek, G AF Kharche, Neerav Prada, Marta Boykin, Timothy B. Klimek, Gerhard TI Valley splitting in strained silicon quantum wells modeled with 2 degrees miscuts, step disorder, and alloy disorder SO APPLIED PHYSICS LETTERS LA English DT Article ID INVERSION-LAYERS; MINIGAPS; DOTS AB Valley splitting (VS) in strained SiGe/Si/SiGe quantum wells grown on (001) and 2 degrees miscut substrates is computed in a magnetic field. Calculations of flat structures significantly overestimate, while calculations of perfectly ordered structures underestimate experimentally observed VS. Step disorder and confinement alloy disorder raise the VS to the experimentally observed levels. Atomistic alloy disorder is identified as the critical physics, which cannot be modeled with analytical effective mass theory. NEMO-3D is used to simulate up to 10(6) atoms, where strain is computed in the valence-force field and electronic structure in the sp(3)d(5)s(*) model. (c) 2007 American Institute of Physics. C1 Purdue Univ, Sch Elect & Comp Engn, W Lafayette, IN 47907 USA. Purdue Univ, Network Computat Nanotechnol, W Lafayette, IN 47907 USA. Univ Alabama, Dept Elect & Comp Engn, Huntsville, AL 35899 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Kharche, N (reprint author), Purdue Univ, Sch Elect & Comp Engn, W Lafayette, IN 47907 USA. EM nkharche@purdue.edu RI Kharche, Neerav/F-4331-2015; Klimeck, Gerhard/A-1414-2012 OI Kharche, Neerav/0000-0003-1014-6022; Klimeck, Gerhard/0000-0001-7128-773X NR 25 TC 65 Z9 65 U1 0 U2 5 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD FEB 26 PY 2007 VL 90 IS 9 AR 092109 DI 10.1063/1.2591432 PG 3 WC Physics, Applied SC Physics GA 141PR UT WOS:000244591700048 ER PT J AU Robin, J Dubayah, R Sparrow, E Levine, E AF Robin, Jessica Dubayah, Ralph Sparrow, Elena Levine, Elissa TI Monitoring start of season in Alaska with GLOBE, AVHRR, and MODIS data SO JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES LA English DT Article ID DIFFERENCE VEGETATION INDEX; CLIMATE-CHANGE; MINIMUM TEMPERATURE; SPRING PHENOLOGY; BOREAL REGIONS; TIME-SERIES; TRENDS; VARIABILITY; COVER; NDVI AB This work evaluates whether continuity between Advanced Very High Resolution Radiometer (AVHRR) and Moderate Resolution Imaging Spectroradiometer (MODIS) normalized difference vegetation index (NDVI) is achievable for monitoring phenological changes in Alaska. This work also evaluates whether NDVI can detect changes in start of the growing season (SOS) in this region. Six quadratic regression models with NDVI as a function of accumulated growing degree days (AGDD) were developed from 2001 through 2004 AVHRR and MODIS NDVI data sets for urban, mixed, and forested land covers. Model parameters determined NDVI values for start of the observational period as well as peak and length of the growing season. NDVI values for start of the growing season were determined from the model equations and field observations of SOS made by GLOBE students and researchers at University of Alaska Fairbanks. AGDD was computed from daily air temperature. AVHRR and MODIS models were significantly different from one another with differences in the start of the observational season as well as start, peak, and length of the growing season. Furthermore, AGDD for SOS was significantly lower during the 1990s than the 1980s. NDVI values at SOS did not detect this change. There are limitations with using NDVI to monitor phenological changes in these regions because of snow, the large extent of conifers, and clouds, which restrict the composite period. In addition, differing processing and spectral characteristics restrict continuity between AVHRR and MODIS NDVI data sets. C1 [Robin, Jessica; Levine, Elissa] NASA, Goddard Space Flight Ctr, Biospher Sci Branch, Greenbelt, MD 20771 USA. [Robin, Jessica; Dubayah, Ralph] Univ Maryland, Dept Geog, College Pk, MD 20742 USA. [Sparrow, Elena] Univ Alaska Fairbanks, Sch Nat Resources & Agr Sci, Fairbanks, AK 99775 USA. RP Robin, J (reprint author), NASA, Goddard Space Flight Ctr, Biospher Sci Branch, Code 614-4, Greenbelt, MD 20771 USA. EM jrobin@ltpmail.gsfc.nasa.gov NR 73 TC 7 Z9 7 U1 0 U2 6 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-8953 EI 2169-8961 J9 J GEOPHYS RES-BIOGEO JI J. Geophys. Res.-Biogeosci. PD FEB 26 PY 2007 VL 113 IS G1 AR G01017 DI 10.1029/2007JG000407 PG 10 WC Environmental Sciences; Geosciences, Multidisciplinary SC Environmental Sciences & Ecology; Geology GA 270JC UT WOS:000253716100001 ER PT J AU Kathuroju, N White, MA Symanzik, J Schwartz, MD Powell, JA Nemani, RR AF Kathuroju, Naven White, Michael A. Symanzik, Jurgen Schwartz, Mark D. Powell, James A. Nemani, Ramakrishna R. TI On the use of the advanced very high resolution radiometer for development of prognostic land surface phenology models SO ECOLOGICAL MODELLING LA English DT Article DE budburst; climate change; senescence; leaf out; growing season; interannual variability; Spring; Fall; canopy duration; carbon; GCM ID LEAF-AREA INDEX; SATELLITE DATA; METEOROLOGICAL VARIABLES; DECIDUOUS FOREST; COMPOSITE IMAGES; GROWING-SEASON; UNITED-STATES; VEGETATION; VARIABILITY; CLIMATE AB Regulation of interannual phenological variability is an important component of climate and ecological models. Prior phenological efforts using the advanced very high resolution radiometer (AVHRR) as a proxy of vegetation dynamics have often simulated spring events only or failed to simulate interannual variability. Our aim is to address these shortcomings and to use the AVHRR to develop prognostic models for interannual land surface phenology and, critically, to test whether or not the developed models are superior to use of climatological phenology values from the AVHRR. Using datasets for the conterminous United States, we first filtered data to select regions and plant functional types for which the best-possible remotely sensed signal could be obtained. We then used a generalized linear model approach to model the relationship between an integrative productivity index and estimates of the start of season (SOS) and end of season (EOS) derived from the AVHRR, yielding models capable of prognostically predicting SOS/EOS events independently of satellite data. Mean absolute errors between the model-predicted and AVHRR-observed SOS/EOS ranged from 5.1 to 20.3 days. SOS errors were uniformly lower than EOS errors. SOS models for the deciduous broadleaf forest and grassland plant functional types produced lower errors than use of the climatological SOS values while all other models produced errors higher than those obtained from the climatological dates. Based on this criterion for success, we suggest that the AVHRR may not be appropriate for further development of prognostic land surface phenology models. However, an intercomparison of phenological dates from an independent spring index model, our model predictions, and the AVHRR observations indicated that interannual predictions from our models may be superior to the satellite data upon which they are based, implying that a further comparison between models based on the AVHRR and newer, superior sensors, should be conducted. (c) 2006 Elsevier B.V All rights reserved. C1 Utah State Univ, Dept Watershed Sci, Logan, UT 84322 USA. Utah State Univ, Dept Math & Stat, Logan, UT 84322 USA. Univ Wisconsin, Dept Geog, Milwaukee, WI 53201 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP White, MA (reprint author), Utah State Univ, Dept Watershed Sci, Logan, UT 84322 USA. EM mikew@cc.usu.edu OI White, Michael/0000-0002-0238-8913 NR 53 TC 28 Z9 31 U1 0 U2 15 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0304-3800 EI 1872-7026 J9 ECOL MODEL JI Ecol. Model. PD FEB 24 PY 2007 VL 201 IS 2 BP 144 EP 156 DI 10.1016/j.ecolmodel.2006.09.011 PG 13 WC Ecology SC Environmental Sciences & Ecology GA 137GX UT WOS:000244282200004 ER PT J AU Leask, HJ Wilson, L Mitchell, KL AF Leask, Harald J. Wilson, Lionel Mitchell, Karl L. TI Formation of Mangala Fossa, the source of the Mangala Valles, Mars: Morphological development as a result of volcano-cryosphere interactions SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID CERBERUS FOSSAE; HYDROLOGICAL CYCLE; MARTIAN CHANNELS; OUTFLOW CHANNELS; THARSIS REGION; WATER; SURFACE; GROUNDWATER; FEATURES; SYSTEMS AB [ 1] The morphology of the Mangala Fossa graben forming the source of the Mangala Valles implies that two episodes of graben subsidence took place, each induced by lateral dike intrusion from Arsia Mons. Quantitative modeling suggests that graben boundary faults breaching the cryosphere provided pathways for water release from an underlying aquifer at a peak rate of similar to 10(7) m(3) s(-1). In the first event, the graben subsided by similar to 200 m, and water carrying a thin ice layer filled the graben, overflowing after similar to 2.5 hours, mainly at a low point on the north rim. This captured the water flux, eroding a gap in the north wall which, with an erosion rate of similar to 100 mu m s(-1) and a duration of similar to 1 month, was similar to 250 m deep by the end of water release. Erosion of the graben floor also took place, at similar to 20 mu m s(-1), lowering it by similar to 50 m. Subsequently, heat from the cooling dike melted cryosphere ice, causing a further similar to 150 m of subsidence on compaction. In the second event, with a similar duration and peak discharge, the graben again subsided by similar to 200 m and filled with ice-covered water until overflow through the gap began at a water depth of similar to 350 m. The gap was eroded down by a further similar to 400 m, and the floor was eroded by a further similar to 50 m. Finally, heat from the second dike sublimed cryosphere ice, lowering the floor by similar to 100 m. In places, combined erosion and subsidence of the graben floor exposed similar to 200 m of the first dike. C1 Univ Lancaster, Planetary Sci Res Grp, Dept Environm Sci, Lancaster LA1 4YQ, England. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Wilson, L (reprint author), Univ Lancaster, Planetary Sci Res Grp, Dept Environm Sci, Lancaster LA1 4YQ, England. EM l.wilson@Lancaster.ac.uk NR 60 TC 8 Z9 8 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD FEB 24 PY 2007 VL 112 IS E2 AR E02011 DI 10.1029/2005JE002644 PG 16 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 140BU UT WOS:000244478100001 ER PT J AU Jourdain, L Worden, HM Worden, JR Bowman, K Li, Q Eldering, A Kulawik, SS Osterman, G Boersma, KF Fisher, B Rinsland, CP Beer, R Gunson, M AF Jourdain, L. Worden, H. M. Worden, J. R. Bowman, K. Li, Q. Eldering, A. Kulawik, S. S. Osterman, G. Boersma, K. F. Fisher, B. Rinsland, C. P. Beer, R. Gunson, M. TI Tropospheric vertical distribution of tropical Atlantic ozone observed by TES during the northern African biomass burning season SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID EMISSION SPECTROMETER; SATELLITE-OBSERVATIONS; GLOBAL-MODEL; WAVE-ONE; TOMS; VARIABILITY; TRANSPORT; INVENTORY; MAXIMUM AB We present vertical distributions of ozone from the Tropospheric Emission Spectrometer (TES) over the tropical Atlantic Ocean during January 2005. Between 10N and 20S, TES ozone retrievals have Degrees of Freedom for signal (DOF) around 0.7 - 0.8 each for tropospheric altitudes above and below 500 hPa. As a result, TES is able to capture for the first time from space a distribution characterized by two maxima: one in the lower troposphere north of the ITCZ and one in the middle and upper troposphere south of the ITCZ. We focus our analysis on the north tropical Atlantic Ocean, where most of previous satellite observations showed discrepancies with in-situ ozone observations and models. Trajectory analyses and a sensitivity study using the GEOS-Chem model confirm the influence of northern Africa biomass burning on the elevated ozone mixing ratios observed by TES over this region. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Harvard Univ, Dept Earth & Planetary Sci, Cambridge, MA 02138 USA. Harvard Univ, Div Engn & Appl Sci, Cambridge, MA 02138 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Jourdain, L (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM line.jourdain@jpl.nasa.gov RI Boersma, Klaas/H-4559-2012; Chem, GEOS/C-5595-2014 OI Boersma, Klaas/0000-0002-4591-7635; NR 32 TC 45 Z9 45 U1 0 U2 6 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 EI 1944-8007 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD FEB 23 PY 2007 VL 34 IS 4 AR L04810 DI 10.1029/2006GL028284 PG 6 WC Geosciences, Multidisciplinary SC Geology GA 140AQ UT WOS:000244474800003 ER PT J AU Schorghofer, N Taylor, GJ AF Schorghofer, Norbert Taylor, G. Jeffrey TI Subsurface migration of H2O at lunar cold traps SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID POLAR-REGIONS; ICE DEPOSITS; NORTH-POLE; MOON; MERCURY; WATER; SURFACE; STABILITY; EVAPORATION; SUBLIMATION AB [1] Permanently shaded areas near the poles of the Moon and Mercury may harbor water ice. We develop a physical model for migration of water molecules in the regolith and discover two pathways that can lead to accumulation of H2O in the subsurface. A small fraction of water molecules delivered, either continuously or abruptly, to permanently cold areas diffuses into the regolith and can remain there longer than on the surface. Higher temperatures lead to deeper burial. At constant temperature, this diffusive migration produces less than one molecular layer of volatile H2O on grains, because it is driven by differences in surface concentrations. The water is therefore expected to be in adsorbed form, and the amount stored in this fashion could be at most a few hundred ppm of H2O. A second pathway is pumping by diurnal temperature oscillations from a transient ice cover that may have formed during a large comet impact. It can lead to high ground ice densities, but the ground ice layer lasts not long beyond the disappearance of the ice cover. Both types of subsurface charging mechanism work best for temperatures typical of permanently shaded areas with sunlit surfaces in their field of view. C1 Univ Hawaii, Inst Astron, Honolulu, HI 96822 USA. Univ Hawaii, NASA Astrobiol Inst, Honolulu, HI USA. Univ Hawaii, Hawaii Inst Geophys & Planetol, Honolulu, HI 96822 USA. RP Schorghofer, N (reprint author), Univ Hawaii, Inst Astron, 2680 Woodlawn Dr, Honolulu, HI 96822 USA. EM norbert@hawaii.edu; gjtaylor@higp.hawaii.edu RI Schorghofer, Norbert/A-1194-2007 NR 40 TC 28 Z9 28 U1 0 U2 8 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD FEB 23 PY 2007 VL 112 IS E2 AR E02010 DI 10.1029/2006JE002779 PG 11 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 140BT UT WOS:000244478000002 ER PT J AU Gehrels, N Cannizzo, JK Norris, JP AF Gehrels, N. Cannizzo, J. K. Norris, J. P. TI Gamma-ray bursts in the Swift era SO NEW JOURNAL OF PHYSICS LA English DT Article ID 28 FEBRUARY 1997; HOST GALAXY; REDSHIFT DISTRIBUTION; AFTERGLOW EMISSION; STAR-FORMATION; LONG; TELESCOPE; SUPERNOVA; GRB-050709; UNIVERSE AB Gamma-ray burst (GRB) research has undergone a revolution in the last two years. The launch of Swift, with its rapid slewing capability, has greatly increased the number and quality of GRB localizations and x-ray and optical afterglow lightcurves. Over 160 GRBs have been detected, and nearly all have been followed up with the on-board narrow field telescopes. Advances in our understanding of short GRBs have been spectacular. The detection of x-ray afterglows has led to accurate localizations from ground based observatories, which have given host identifications and redshifts. Theoretical models for short GRB progenitors have, for the first time, been placed on a sound foundation. The hosts for the short GRBs differ in a fundamental way from the long GRB hosts: short GRBs tend to occur in non-star forming galaxies or regions, whereas long GRBs are strongly concentrated within star forming regions. Observations are consistent with a binary neutron star merger model, but other models involving old stellar populations are also viable. Swift has greatly increased the redshift range of GRB detection. The highest redshift GRBs, at z similar to 5-6, are approaching the era of reionization. Ground-based deep optical spectroscopy of high redshift bursts is giving metallicity measurements and other information on the source environment to much greater distance than other techniques. The localization of GRB 060218 to a nearby galaxy, and association with SN2006aj, added a valuable member to the class of GRBs with a detected supernova. The prospects for future progress are excellent given the >10 year orbital lifetime of the Swift satellite. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Gehrels, N (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. EM gehrels@milkyway.gsfc.nasa.gov RI Gehrels, Neil/D-2971-2012 NR 88 TC 22 Z9 22 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 1367-2630 J9 NEW J PHYS JI New J. Phys. PD FEB 23 PY 2007 VL 9 AR 37 DI 10.1088/1367-2630/9/2/037 PG 21 WC Physics, Multidisciplinary SC Physics GA 138YZ UT WOS:000244400500002 ER PT J AU LaDochy, S Medina, R Patzert, W AF LaDochy, Steve Medina, Richard Patzert, William TI Recent California climate variability: spatial and temporal patterns in temperature trends SO CLIMATE RESEARCH LA English DT Article DE climate variability; California climate; Landuse change ID URBANIZATION; IMPACTS AB With mounting evidence that global warming is taking place, the cause of this warming has come under vigorous scrutiny. Recent studies have lead to a debate over what contributes the most to regional temperature changes. We investigated air temperature patterns in California from 1950 to 2000. Statistical analyses were used to test the significance of temperature trends in California subregions in an attempt to clarify the spatial and temporal patterns of the occurrence and intensities of warming. Most regions showed a stronger increase in minimum temperatures than with mean and maximum temperatures. Areas of intensive urbanization showed the largest positive trends, while rural, non-agricultural regions showed the least warming. Strong correlations between temperatures and Pacific sea surface temperatures (SSTs) particularly Pacific Decadal Oscillation (PDO) values, also account for temperature variability throughout the state. The analysis of 331 state weather stations associated a number of factors with temperature trends, including urbanization, population, Pacific oceanic conditions and elevation. Using climatic division mean temperature trends, the state had an average warming of 0.99 degrees C (1.79 degrees F) over the 1950-2000 period, or 0.20 degrees C (0.36 degrees F) decade. Southern California had the highest rates of warming, while the NE Interior Basins division experienced cooling. Large urban sites showed rates over twice those for the state, for the mean maximum temperatures, and over 5 times the state's mean rate for the minimum temperatures. In comparison, irrigated cropland sites warmed about 0.13 degrees C decade(-1) annually, but near 0.40 degrees C for summer and fall minima. Offshore Pacific SSTs warmed 0.09 degrees C decade(-1) for the study period. C1 Calif State Univ Los Angeles, Dept Geog & Urban Anal, Los Angeles, CA 90032 USA. NASA, Jet Prop Lab, Pasadena, CA 91109 USA. RP LaDochy, S (reprint author), Calif State Univ Los Angeles, Dept Geog & Urban Anal, 5151 State Univ Dr, Los Angeles, CA 90032 USA. EM sladoch@calstatela.edu NR 27 TC 46 Z9 46 U1 1 U2 19 PU INTER-RESEARCH PI OLDENDORF LUHE PA NORDBUNTE 23, D-21385 OLDENDORF LUHE, GERMANY SN 0936-577X J9 CLIM RES JI Clim. Res. PD FEB 22 PY 2007 VL 33 IS 2 BP 159 EP 169 DI 10.3354/cr033159 PG 11 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA 147IX UT WOS:000244997700004 ER PT J AU Sulsky, D Schreyer, H Peterson, K Kwok, R Coon, M AF Sulsky, Deborah Schreyer, Howard Peterson, Kara Kwok, Ron Coon, Max TI Using the material-point method to model sea ice dynamics SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID IN-CELL METHOD; STOCHASTIC AVERAGE; FLIP; SIMULATION; PLASTICITY; PRESSURE; FAILURE; FLOW; LAW AB [ 1] The material-point method (MPM) is a numerical method for continuum mechanics that combines the best aspects of Lagrangian and Eulerian discretizations. The material points provide a Lagrangian description of the ice that models convection naturally. Thus properties such as ice thickness and compactness are computed in a Lagrangian frame and do not suffer from errors associated with Eulerian advection schemes, such as artificial diffusion, dispersion, or oscillations near discontinuities. This desirable property is illustrated by solving transport of ice in uniform, rotational and convergent velocity fields. Moreover, the ice geometry is represented by unconnected material points rather than a grid. This representation facilitates modeling the large deformations observed in the Arctic, as well as localized deformation along leads, and admits a sharp representation of the ice edge. MPM also easily allows the use of any ice constitutive model. The versatility of MPM is demonstrated by using two constitutive models for simulations of wind-driven ice. The first model is a standard viscous-plastic model with two thickness categories. The MPM solution to the viscous-plastic model agrees with previously published results using finite elements. The second model is a new elastic-decohesive model that explicitly represents leads. The model includes a mechanism to initiate leads, and to predict their orientation and width. The elastic-decohesion model can provide similar overall deformation as the viscous-plastic model; however, explicit regions of opening and shear are predicted. Furthermore, the efficiency of MPM with the elastic-decohesive model is competitive with the current best methods for sea ice dynamics. C1 Univ New Mexico, Dept Math & Stat, Albuquerque, NM 87131 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ New Mexico, Dept Engn, Albuquerque, NM 87131 USA. NW Res Associates Inc, Bellevue, WA 98009 USA. RP Sulsky, D (reprint author), Univ New Mexico, Dept Math & Stat, Albuquerque, NM 87131 USA. EM sulsky@math.unm.edu; schreyer@me.unm.edu; kpeterso@math.unm.edu; ron.kwok@nasa.jpl.gov; max@nwra.com RI Kwok, Ron/A-9762-2008 OI Kwok, Ron/0000-0003-4051-5896 NR 52 TC 35 Z9 36 U1 2 U2 9 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-OCEANS JI J. Geophys. Res.-Oceans PD FEB 22 PY 2007 VL 112 IS C2 AR C02S90 DI 10.1029/2005JC003329 PG 18 WC Oceanography SC Oceanography GA 140BR UT WOS:000244477700002 ER PT J AU Richardson, LJ Deming, D Horning, K Seager, S Harrington, J AF Richardson, L. Jeremy Deming, Drake Horning, Karen Seager, Sara Harrington, Joseph TI A spectrum of an extrasolar planet SO NATURE LA English DT Article ID SPITZER-SPACE-TELESCOPE; GIANT PLANETS; HD 209458B; INFRARED OBSERVATIONS; TRANSITING PLANET; SECONDARY ECLIPSE; THERMAL EMISSION; HOT JUPITERS; ATMOSPHERES; HD-209458B AB Of the over 200 known extrasolar planets, 14 exhibit transits in front of their parent stars as seen from Earth. Spectroscopic observations of the transiting planets can probe the physical conditions of their atmospheres(1,2). One such technique(3,4) can be used to derive the planetary spectrum by subtracting the stellar spectrum measured during eclipse ( planet hidden behind star) from the combined-light spectrum measured outside eclipse ( star+planet). Although several attempts have been made from Earth-based observatories, no spectrum has yet been measured for any of the established extrasolar planets. Here we report a measurement of the infrared spectrum (7.5 - 13.2 mu m) of the transiting extrasolar planet HD 209458b. Our observations reveal a hot thermal continuum for the planetary spectrum, with an approximately constant ratio to the stellar flux over this wavelength range. Superposed on this continuum is a broad emission peak centred near 9.65 mu m that we attribute to emission by silicate clouds. We also find a narrow, unidentified emission feature at 7.78 mu m. Models of these 'hot Jupiter('5) planets predict a flux peak(6-9) near 10 mu m, where thermal emission from the deep atmosphere emerges relatively unimpeded by water absorption, but models dominated by water fit the observed spectrum poorly. C1 NASA, Goddard Space Flight Ctr, Exoplanets & Stellar Astrophys Lab, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Planetary Syst Lab, Greenbelt, MD 20771 USA. Florida Inst Technol, Dept Phys & Space Sci, Melbourne, FL 32901 USA. Carnegie Inst Washington, Dept Terr Magnetism, Washington, DC 20015 USA. MIT, Dept Earth Atmospher & Planetary Sci, Cambridge, MA 02139 USA. Univ Cent Florida, Dept Phys, Orlando, FL 32816 USA. RP Richardson, LJ (reprint author), NASA, Goddard Space Flight Ctr, Exoplanets & Stellar Astrophys Lab, Mail Code 667, Greenbelt, MD 20771 USA. EM lee.richardson@colorado.edu RI Harrington, Joseph/E-6250-2011; OI Harrington, Joseph/0000-0002-8955-8531 NR 30 TC 124 Z9 125 U1 2 U2 10 PU NATURE PUBLISHING GROUP PI LONDON PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD FEB 22 PY 2007 VL 445 IS 7130 BP 892 EP 895 DI 10.1038/nature05636 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 138CR UT WOS:000244341200043 PM 17314975 ER PT J AU Bell, RE Studinger, M Shuman, CA Fahnestock, MA Joughin, I AF Bell, Robin E. Studinger, Michael Shuman, Christopher A. Fahnestock, Mark A. Joughin, Ian TI Large subglacial lakes in East Antarctica at the onset of fast-flowing ice streams SO NATURE LA English DT Article ID VOSTOK; WATER; DISCHARGE; ORIGIN AB Water plays a crucial role in ice-sheet stability and the onset of ice streams. Subglacial lake water moves between lakes(1) and rapidly drains, causing catastrophic floods(2). The exact mechanisms by which subglacial lakes influence ice-sheet dynamics are unknown, however, and large subglacial lakes(3,4) have not been closely associated with rapidly flowing ice streams. Here we use satellite imagery and ice-surface elevations to identify a region of subglacial lakes, similar in total area to Lake Vostok, at the onset region of the Recovery Glacier ice stream in East Antarctica and predicted by ice-sheet models(5). We define four lakes through extensive, flat, featureless regions of ice surface bounded by upstream troughs and downstream ridges. Using ice velocities determined using interferometric synthetic aperture radar (InSAR), we find the onset of rapid flow ( moving at 20 to 30 m yr(-1)) of the tributaries to the Recovery Glacier ice stream in a 280-km-wide segment at the downslope margins of these four subglacial lakes. We conclude that the subglacial lakes initiate and maintain rapid ice flow through either active modification of the basal thermal regime of the ice sheet by lake accretion or through scouring bedrock channels in periodic drainage events. We suggest that the role of subglacial lakes needs to be considered in ice-sheet mass balance assessments. C1 Columbia Univ, Lamont Doherty Earth Observ, Palisades, NY 10964 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ New Hampshire, Inst Study Earth Oceans & Space, Durham, NH 03824 USA. Univ Washington, Appl Phys Lab, Seattle, WA 98105 USA. RP Bell, RE (reprint author), Columbia Univ, Lamont Doherty Earth Observ, Palisades, NY 10964 USA. EM robinb@ldeo.columbia.edu RI Joughin, Ian/A-2998-2008; Fahnestock, Mark/N-2678-2013 OI Joughin, Ian/0000-0001-6229-679X; NR 22 TC 121 Z9 126 U1 1 U2 40 PU NATURE PUBLISHING GROUP PI LONDON PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 EI 1476-4687 J9 NATURE JI Nature PD FEB 22 PY 2007 VL 445 IS 7130 BP 904 EP 907 DI 10.1038/nature05554 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 138CR UT WOS:000244341200046 PM 17314977 ER PT J AU Abe, K Sanuki, T Anraku, K Asaoka, Y Fuke, H Haino, S Ikeda, N Imori, M Izumi, K Maeno, T Makida, Y Matsuda, S Matsui, N Matsukawa, T Matsumoto, H Mitchell, JW Moiseev, AA Nishimura, J Nozaki, M Orito, S Ormes, JE Sasaki, M Seo, ES Shikaze, Y Sonoda, T Streitmatter, RE Suzuki, J Tanaka, K Tanizaki, K Yamagami, T Yamamoto, A Yamamoto, Y Yamato, K Yoshida, T Yoshimura, K AF Abe, K. Sanuki, T. Anraku, K. Asaoka, Y. Fuke, H. Haino, S. Ikeda, N. Imori, M. Izumi, K. Maeno, T. Makida, Y. Matsuda, S. Matsui, N. Matsukawa, T. Matsumoto, H. Mitchell, J. W. Moiseev, A. A. Nishimura, J. Nozaki, M. Orito, S. Ormes, J. E. Sasaki, M. Seo, E. S. Shikaze, Y. Sonoda, T. Streitmatter, R. E. Suzuki, J. Tanaka, K. Tanizaki, K. Yamagami, T. Yamamoto, A. Yamamoto, Y. Yamato, K. Yoshida, T. Yoshimura, K. TI Measurements of proton, helium and muon spectra at small atmospheric depths with the BESS spectrometer (vol 564, pg 8, 2003) SO PHYSICS LETTERS B LA English DT Correction C1 Univ Tokyo, Tokyo 1130033, Japan. Kobe Univ, Kobe, Hyogo 6578501, Japan. High Energy Accelerator Res Org, KEK, Tsukuba, Ibaraki 3050801, Japan. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Maryland, College Pk, MD 20742 USA. ISAS, Sagamihara, Kanagawa 2298510, Japan. RP Abe, K (reprint author), Univ Tokyo, ICRR, Kamioka Observ, Gifu, Japan. EM abe@suketto.icrr.u-tokyo.ac.jp NR 1 TC 2 Z9 2 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0370-2693 J9 PHYS LETT B JI Phys. Lett. B PD FEB 22 PY 2007 VL 645 IS 5-6 BP 472 EP 475 DI 10.1016/j.physletb.2006.12.046 PG 4 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 140WY UT WOS:000244538700017 ER PT J AU Dye, S Eales, SA Ashby, MLN Huang, JS Egami, E Brodwin, M Lilly, S Webb, T AF Dye, S. Eales, S. A. Ashby, M. L. N. Huang, J. -S. Egami, E. Brodwin, M. Lilly, S. Webb, T. TI A SCUBA/Spitzer investigation of the far-infrared extragalactic background SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE infrared : galaxies; submillimetre ID SPITZER-SPACE-TELESCOPE; 14 HOUR FIELD; MULTIBAND IMAGING PHOTOMETER; DEEP SUBMILLIMETER SURVEY; EXPERIMENT SEARCH; SOURCE COUNTS; GALAXY SURVEY; SCUBA; IDENTIFICATIONS; DETECTIONS AB We have measured the contribution of submillimetre and mid-infrared sources to the extragalactic background radiation at 70 and 160 mu m. Specifically, we have stacked flux in 70- and 160-mu m Spitzer Space Telescope (Spitzer) observations of the Canada-United Kingdom Deep Submillimetre Survey 14-h field at the positions of 850-mu m sources detected by SCUBA and also 8- and 24-mu m sources detected by Spitzer. We find that per source, the SCUBA galaxies are the strongest and the 8-mu m sources the weakest contributors to the background flux at both 70 and 160 mu m. Our estimate of the contribution of the SCUBA sources is higher than previous estimates. However, expressed as a total contribution, the full 8-mu m source catalogue accounts for twice the total 24-mu m source contribution and similar to 10 times the total SCUBA source contribution. The 8-mu m sources account for the majority of the background radiation at 160 mu m with a flux of 0.87 +/- 0.16 MJy sr(-1) and at least a third at 70 mu m with a flux of 0.103 +/- 0.019 MJy sr(-1). These measurements are consistent with current lower limits on the background at 70 and 160 mu m. Finally, we have investigated the 70- and 160-mu m emission from the 8- and 24-mu m sources as a function of redshift. We find that the average 70-mu m flux per 24-mu m source and the average 160-mu m flux per 8- and 24-mu m source is constant over all redshifts, up to z similar to 4. In contrast, the low-redshift half (z < 1) of the of 8-mu m sample contributes approximately four times the total 70-mu m flux of the high-redshift half. These trends can be explained by a single non-evolving SED. C1 Univ Cardiff Wales, Sch Phys & Astron, Cardiff CF24 3AA, Wales. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. ETH, Astron Inst, CH-8093 Zurich, Switzerland. Sterrewacht Leiden, NL-233 CA Leiden, Netherlands. RP Dye, S (reprint author), Univ Cardiff Wales, Sch Phys & Astron, Queens Bldg, Cardiff CF24 3AA, Wales. EM s.dye@astro.cf.ac.uk OI Dye, Simon/0000-0002-1318-8343 NR 29 TC 18 Z9 18 U1 0 U2 0 PU BLACKWELL PUBLISHING PI OXFORD PA 9600 GARSINGTON RD, OXFORD OX4 2DQ, OXON, ENGLAND SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD FEB 21 PY 2007 VL 375 IS 2 BP 725 EP 734 DI 10.1111/j.1365-2966.2006.11340.x PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 134KY UT WOS:000244083100027 ER PT J AU Eriksen, HK Huey, G Saha, R Hansen, FK Dick, J Banday, AJ Gorski, KM Jain, P Jewell, JB Knox, L Larson, DL O'Dwyer, IJ Souradeep, T Wandelt, BD AF Eriksen, H. K. Huey, Greg Saha, R. Hansen, F. K. Dick, J. Banday, A. J. Gorski, K. M. Jain, P. Jewell, J. B. Knox, L. Larson, D. L. O'Dwyer, I. J. Souradeep, T. Wandelt, B. D. TI A reanalysis of the 3 year Wilkinson Microwave Anisotropy Probe temperature power spectrum and likelihood SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmic microwave background; cosmology : observations; methods : numerical ID 2003 FLIGHT; WMAP OBSERVATIONS; BOOMERANG; MAPS AB We analyze the 3 yr Wilkinson Microwave Anisotropy Probe ( WMAP) temperature anisotropy data seeking to confirm the power spectrum and likelihoods published by the WMAP team. We apply five independent implementations of four algorithms to the power spectrum estimation and two implementations to the parameter estimation. Our single most important result is that we broadly confirm the WMAP power spectrum and analysis. Still, we do find two small but potentially important discrepancies. On large angular scales there is a small power excess in the WMAP spectrum ( 5% - 10% at l less than or similar to 30) primarily due to likelihood approximation issues between 13 <= l less than or similar to 30. On small angular scales there is a systematic difference between the V- and W-band spectra ( few percent at l greater than or similar to 300). Recently, the latter discrepancy was explained by Huffenberger et al. ( 2006) in terms of oversubtraction of unresolved point sources. As far as the low-l bias is concerned, most parameters are affected by a few tenths of a sigma. The most important effect is seen in n(s). For the combination of WMAP, ACBAR, and BOOMERANG, the significance of ns 6 1 drops from similar to 2.7 sigma to similar to 2.3 sigma when correcting for this bias. We propose a few simple improvements to the low-l WMAP likelihood code, and introduce two important extensions to the Gibbs sampling method that allows for proper sampling of the low signal-to-noise ratio regime. Finally, we make the products from the Gibbs sampling analysis publicly available, thereby providing a fast and simple route to the exact likelihood without the need of expensive matrix inversions. C1 Univ Oslo, Inst Theoret Astrophys, Oslo, Norway. Univ Oslo, Ctr Math Applicat, Oslo, Norway. Jet Propuls Lab, Pasadena, CA USA. CALTECH, Pasadena, CA 91125 USA. Univ Illinois, Dept Phys, Urbana, IL 61801 USA. Indian Inst Technol, Dept Phys, Kanpur 208016, Uttar Pradesh, India. Univ Calif Davis, Dept Phys, Davis, CA 95616 USA. Max Planck Inst Astrophys, D-85741 Garching, Germany. Univ Warsaw Observ, Warsaw, Poland. Univ Illinois, Dept Astron, Urbana, IL USA. Inter Univ Ctr Astron & Astrophys, Ganeshkhind, India. RP Eriksen, HK (reprint author), Univ Oslo, Inst Theoret Astrophys, Oslo, Norway. EM h.k.k.eriksen@astro.uio.no OI WANDELT, Benjamin/0000-0002-5854-8269 NR 30 TC 57 Z9 57 U1 0 U2 2 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X EI 1538-4357 J9 ASTROPHYS J JI Astrophys. J. PD FEB 20 PY 2007 VL 656 IS 2 BP 641 EP 652 DI 10.1086/509911 PN 1 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 138BG UT WOS:000244336900003 ER PT J AU Larson, DL Eriksen, HK Wandelt, BD Gorski, KM Huey, G Jewell, JB O'Dwyer, IJ AF Larson, D. L. Eriksen, H. K. Wandelt, B. D. Gorski, K. M. Huey, Greg Jewell, J. B. O'Dwyer, I. J. TI Estimation of polarized power spectra by Gibbs sampling SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmic microwave background; cosmology : observations; methods : numerical ID ANGULAR SCALE INTERFEROMETER; MICROWAVE AB Earlier papers introduced a method of accurately estimating the angular cosmic microwave background temperature power spectrum based on Gibbs sampling. Here we extend this framework to polarized data. All advantages of the Gibbs sampler still apply, and exact analysis of megapixel polarized data sets is thus feasible. These advantages may be even more important for polarization measurements than for temperature measurements. While approximate methods can alias power from the larger E-mode spectrum into the weaker B-mode spectrum, the Gibbs sampler ( or equivalently, exact likelihood evaluations) allows for a statistically optimal separation of these modes in terms of power spectra. To demonstrate the method, we analyze two simulated data sets: ( 1) a hypothetical future CMBPol mission, with the focus on B-mode estimation; and ( 2) a Planck-like mission, to highlight the computational feasibility of the method. C1 Univ Illinois, Dept Phys, Urbana, IL 61801 USA. Univ Oslo, Inst Theoret Astrophys, Oslo, Norway. Univ Oslo, Ctr Math Applicat, Oslo, Norway. Jet Propuls Lab, Pasadena, CA USA. CALTECH, Pasadena, CA 91125 USA. Univ Illinois, Dept Astron, Urbana, IL 61801 USA. Univ Warsaw Observ, Warsaw, Poland. RP Larson, DL (reprint author), Univ Illinois, Dept Phys, 1110 W Green St, Urbana, IL 61801 USA. EM dlarson1@uiuc.edu OI WANDELT, Benjamin/0000-0002-5854-8269 NR 20 TC 39 Z9 39 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD FEB 20 PY 2007 VL 656 IS 2 BP 653 EP 660 DI 10.1086/509802 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 138BG UT WOS:000244336900004 ER PT J AU Nevalainen, J Bonamente, M Kaastra, J AF Nevalainen, J. Bonamente, M. Kaastra, J. TI Revisiting the soft X-ray excess emission in clusters of galaxies observed with XMM-Newton SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : clusters : general; galaxies : clusters : individual (A1835; Abell 1795, AS1101, MKW 3s); X-rays : galaxies : clusters AB We analyze XMM-Newton galaxy clusters Abell 1795, Abell S1101, Abell 1835, and MKW 3s in order to test whether their soft X-ray excess emission in the 0.2Y0.5 keV band as reported by Kaastra et al. maintains after application of current knowledge of the XMM-Newton background and calibration. In this context, we examine the claim (Bregman & Lloyd-Davies) that the XMM-Newton sub-Galactic Hi column density, and the accompanying soft excess continuum emission in the 0.2Y0.5 keV band, is an artifact of an incorrect background subtraction. We show that since the cluster regions under scrutiny are within 500 kpc of the bright cluster center, the X-ray background level is negligible compared to the cluster emission level. Thus, at least in the central 500 kpc regions of the studied clusters, the reported soft excess is not a background artifact. We also study the possibility that the incomplete calibration information in the early phase of the XMM-Newton mission resulted in sub-Galactic HI column density, which was interpreted with the presence of a soft excess emitter. Our reanalysis of the four XMM-Newton observations with the MOS instruments yields evidence for the soft excess in all clusters. However, using the PN instrument, the best-fit HI column densities in Abell 1795, Abell 1835, and MKW 3s are at odds with the 2003 analysis of Kaastra et al. and in general agreement with those measured from 21 cm data in the direction of the clusters (Dickey & Lockman). Abell S1101 continues to feature a sub-Galactic NH also with the PN instrument, indicative of soft excess emission in both EPIC detectors. These differences are compatible with the current level of uncertainty in the calibration of both instruments. C1 Univ Helsinki, Observ, Helsinki, Finland. NASA, Natl Space Sci Technol Ctr, Huntsville, AL USA. Univ Alabama, Dept Phys, Huntsville, AL 35899 USA. SRON, Utrecht, Netherlands. RP Nevalainen, J (reprint author), Univ Helsinki, Observ, Helsinki, Finland. EM jnevalai@astro.helsinki.fi; bonamem@uah.edu; j.s.kaastra@sron.nl NR 10 TC 11 Z9 11 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD FEB 20 PY 2007 VL 656 IS 2 BP 733 EP 738 DI 10.1086/510325 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 138BG UT WOS:000244336900012 ER PT J AU Smith, JDT Draine, BT Dale, DA Moustakas, J Kennicutt, RC Helou, G Armus, L Roussel, H Sheth, K Bendo, GJ Buckalew, BA Calzetti, D Engelbracht, CW Gordon, KD Hollenbach, DJ Li, A Malhotra, S Murphy, EJ Walter, F AF Smith, J. D. T. Draine, B. T. Dale, D. A. Moustakas, J. Kennicutt, R. C., Jr. Helou, G. Armus, L. Roussel, H. Sheth, K. Bendo, G. J. Buckalew, B. A. Calzetti, D. Engelbracht, C. W. Gordon, K. D. Hollenbach, D. J. Li, A. Malhotra, S. Murphy, E. J. Walter, F. TI The mid-infrared spectrum of star-forming galaxies: Global properties of polycyclic aromatic hydrocarbon emission SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : active; galaxies : ISM; infrared : galaxies; techniques : spectroscopic ID ULTRALUMINOUS INFRARED GALAXIES; SPITZER-SPACE-TELESCOPE; DIFFUSE INTERSTELLAR-MEDIUM; ACTIVE GALACTIC NUCLEI; DEEP-FIELD-SOUTH; NEARBY GALAXIES; MU-M; SILICATE EMISSION; SPECTROGRAPH IRS; PAH EMISSION AB We present a sample of low-resolution 5-38 mu m Spitzer IRS spectra of the inner few square kiloparsecs of 59 nearby galaxies spanning a large range of star formation properties. A robust method for decomposing mid-infrared galaxy spectra is described and used to explore the behavior of PAH emission and the prevalence of silicate dust extinction. Evidence for silicate extinction is found in similar to (1)/(8) of the sample, at strengths that indicate that most normal galaxies undergo A(V) less than or similar to 3 mag averaged over their centers. The contribution of PAH emission to the total infrared power is found to peak near 10% and extend up to similar to 20% and is suppressed at metallicities Z less than or similar to Z circle dot/4, as well as in low-luminosity AGN environments. Strong interband PAH feature strength variations (2-5 times) are observed, with the presence of a weak AGN and, to a lesser degree, increasing metallicity shifting power to the longer wavelength bands. A peculiar PAH emission spectrum with markedly diminished 5-8 mu m features arises among the sample solely in systems with relatively hard radiation fields harboring low-luminosity AGNs. The AGNs may modify the emitting grain distribution and provide the direct excitation source of the unusual PAH emission, which cautions against using absolute PAH strength to estimate star formation rates in systems harboring active nuclei. Alternatively, the low star formation intensity often associated with weak AGNs may affect the spectrum. The effect of variations in the mid-infrared spectrum on broadband infrared surveys is modeled and points to more than a factor of 2 uncertainty in results that assume a fixed PAH emission spectrum, for redshifts z = 0-2.5. C1 Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. Princeton Univ, Dept Astrophys Sci, Princeton, NJ 08544 USA. Univ Wyoming, Dept Phys & Astron, Laramie, WY 82071 USA. Univ Cambridge, Inst Astron, Cambridge CB3 0HA, England. CALTECH, Pasadena, CA 91125 USA. Spitzer Sci Ctr, Pasadena, CA USA. Max Planck Inst Astron, D-69117 Heidelberg, Germany. Univ London Imperial Coll Sci & Technol, Blackett Lab, London, England. Space Telescope Sci Inst, Baltimore, MD 21218 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ Missouri, Dept Phys & Astron, Columbia, MO 65211 USA. Arizona State Univ, Dept Phys & Astron, Tempe, AZ 85287 USA. Yale Univ, Dept Astron, New Haven, CT 06511 USA. RP Smith, JDT (reprint author), Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. EM jdsmith@as.arizona.edu OI Draine, Bruce/0000-0002-0846-936X NR 97 TC 516 Z9 517 U1 4 U2 31 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD FEB 20 PY 2007 VL 656 IS 2 BP 770 EP 791 DI 10.1086/510549 PN 1 PG 22 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 138BG UT WOS:000244336900016 ER PT J AU Mason, RE Wright, GS Adamson, A Pendleton, Y AF Mason, R. E. Wright, G. S. Adamson, A. Pendleton, Y. TI Spectropolarimetry of the 3.4 mu m absorption feature in NGC 1068 SO ASTROPHYSICAL JOURNAL LA English DT Article DE astrochemistry; dust, extinction; galaxies : individual (NGC 1068); galaxies : ISM; galaxies : Seyfert; polarization ID ACTIVE GALACTIC NUCLEI; DIFFUSE INTERSTELLAR-MEDIUM; MU-M FEATURE; DISCRETE-DIPOLE APPROXIMATION; ORGANIC REFRACTORY MATERIAL; NGC 1068; CARBON GRAINS; SEYFERT-GALAXIES; MICRON BAND; INFRARED SPECTROPOLARIMETRY AB In order to test the silicate-core/organic-mantle model of galactic interstellar dust, we have performed spectro-polarimetry of the 3.4 mu m C - H bond stretch that is characteristic of aliphatic hydrocarbons, using the nucleus of the Seyfert 2 galaxy, NGC 1068, as a bright, dusty background source. Polarization calculations show that if the grains in NGC 1068 had the properties assigned by the core-mantle model to dust in the Galactic diffuse interstellar medium ( ISM), they would cause a detectable rise in polarization over the 3.4 mu m feature. No such increase is observed. We discuss modifications to the basic core-mantle model, such as changes in grain size or the existence of additional nonhydrocarbon aligned grain populations, that could better fit the observational evidence. However, we emphasize that the absence of polarization over the 3.4 mu m band in NGC 1068 - and, indeed, in every line of sight examined to date - can be readily explained by a population of small, unaligned carbonaceous grains with no physical connection to the silicates. C1 Gemini Observ, No Operat Ctr, Hilo, HI 96720 USA. Royal Observ, UK Astron Technol Ctr, Edinburgh EH9 3HJ, Midlothian, Scotland. Joint Astron Ctr, Hilo, HI USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Mason, RE (reprint author), Gemini Observ, No Operat Ctr, Hilo, HI 96720 USA. EM rmason@gemini.edu; gsw@roe.ac.uk; a.adamson@jach.hawaii.edu; ypendleton@mail.arc.nasa.gov NR 80 TC 12 Z9 12 U1 0 U2 2 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD FEB 20 PY 2007 VL 656 IS 2 BP 798 EP 804 DI 10.1086/510608 PN 1 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 138BG UT WOS:000244336900018 ER PT J AU Saumon, D Marley, MS Leggett, SK Geballe, TR Stephens, D Golimowski, DA Cushing, MC Fan, X Rayner, JT Lodders, K Freedman, RS AF Saumon, D. Marley, M. S. Leggett, S. K. Geballe, T. R. Stephens, D. Golimowski, D. A. Cushing, M. C. Fan, X. Rayner, J. T. Lodders, K. Freedman, R. S. TI Physical parameters of two very cool T dwarfs SO ASTROPHYSICAL JOURNAL LA English DT Article DE stars : individual (2MASS J04151954-0935066, 2MASS J12171110-0311131, G1 570D) stars : low-mass, brown dwarfs ID SPITZER-SPACE-TELESCOPE; ALL-SKY SURVEY; BROWN DWARFS; GLIESE 229B; SPECTRAL CLASSIFICATION; INFRARED SPECTROGRAPH; CARBON-MONOXIDE; ATMOSPHERIC CHEMISTRY; GIANT PLANETS; METHANE AB We present new infrared spectra of the T8 brown dwarf 2MASS J04151954 - 0935066: 2.9 - 4.1 mu m spectra obtained with the Infrared Camera and Spectrograph on the Subaru Telescope, and 5.2 - 14.5 mu m spectra obtained with the Infrared Spectrograph on the Spitzer Space Telescope. We use these data and models to determine an accurate bolometric luminosity of log L-bol/ L-circle dot = -5.67 and to constrain the effective temperature, gravity, mass, and age to 725 - 775 K, log g = 5.00 - 5.37, M = 33 - 58 M-Jup, and age = 3 - 10 Gyr. We perform the same analysis using published 0.6 - 15 mu m spectra for the T7.5 dwarf 2MASS J12171110 - 0311131, for which we find a metal-rich composition ([Fe/H] similar to 0: 3), and log L-bol/L-circle dot = -5.31, T-eff = 850 - 950 K, log g = 4.80 - 5.42, M = 25 - 66 M-Jup, and age = 1 - 10 Gyr. These luminosities and effective temperatures straddle those determined with the same method and models for G1 570D by Saumon et al. and make 2MASS J04151954 - 0935066 the coolest and least luminous T dwarf with well-determined properties. We find that synthetic spectra generated by the models reproduce the observed red through mid-infrared spectra of 2MASS J04151954 - 0935066 and 2MASS J12171110 - 0311131 very well, except for known discrepancies that are most likely due to the incomplete CH4 opacities. Both objects show evidence of departures from strict chemical equilibrium, and we discuss this result in the context of other late T dwarfs in which disequilibrium phenomena have been observed. C1 Los Alamos Natl Lab, Los Alamos, NM 87545 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Gemini Observ, Hilo, HI 96720 USA. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. Univ Hawaii, Inst Astron, Honolulu, HI 96822 USA. Washington Univ, Dept Earth & Planetary Sci, St Louis, MO 63130 USA. NASA, Ames Res Ctr, SETI Inst, Moffett Field, CA 94035 USA. RP Saumon, D (reprint author), Los Alamos Natl Lab, Los Alamos, NM 87545 USA. EM dsaumon@lanl.gov OI Leggett, Sandy/0000-0002-3681-2989 NR 49 TC 73 Z9 73 U1 0 U2 3 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD FEB 20 PY 2007 VL 656 IS 2 BP 1136 EP 1149 DI 10.1086/510557 PN 1 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 138BG UT WOS:000244336900045 ER PT J AU Contreras, CS Le Mignant, D Sahai, R de Paz, AG Morris, M AF Contreras, C. Sanchez Le Mignant, D. Sahai, R. de Paz, A. Gil Morris, M. TI Adaptive optics imaging of IRAS 18276-1431: A bipolar preplanetary nebula with circumstellar "searchlight beams" and "ARCS" SO ASTROPHYSICAL JOURNAL LA English DT Article DE circumstellar matter; infrared : stars; instrumentation : adaptive optics; ISM : jets and outflows; planetary nebulae : general; stars : AGB and post-AGB; stars : imaging; stars : mass loss ID GIANT BRANCH STARS; PROTOPLANETARY NEBULA; PLANETARY-NEBULAE; INFRARED OBSERVATIONS; CONTINUUM EMISSION; OH/IR STARS; AGB STARS; MASS-LOSS; ENVELOPES; DUST AB We present high angular resolution images of the post-AGB nebula IRAS 18276 - 1431 (also known as OH 17.7-2.0) obtained with the Keck II adaptive optics (AO) system in its natural guide star (NGS) mode in the K-p, L-p, and M-s near-infrared bands. We also present supporting optical F606W and F814W HST images as well as interferometric observations of the (CO)-C-12 J = 1-0, (CO)-C-13 J = 1-0, and 2.6 mm continuum emission with OVRO. The envelope of IRAS 18276 - 1431 displays a clear bipolar morphology in our optical and NIR images with two lobes separated by a dark waist and surrounded by a faint 4.5" x 3.4" halo. Our K-p-band image reveals two pairs of radial "searchlight beams'' emerging from the nebula center and several intersecting, arclike features. From our CO data we derive a mass of M > 0.38 (D/3 kpc)(2) M-circle dot and an expansion velocity V-exp = 17 km s(-1) for the molecular envelope. The density in the halo follows a radial power law proportional to r(-3), which is consistent with a mass-loss rate increasing with time. Analysis of the NIR colors indicates the presence of a compact central source of similar to 300 - 500 K dust illuminating the nebula in addition to the central star. Modeling of the thermal IR suggests a two-shell structure in the dust envelope: (1) an outer shell with inner and outer radius R-in similar to 1.6 x 10(16) and R-out >= 1.25 x 10(17) cm, dust temperature T-dust similar to 105 - 50 K, and a mean mass-loss rate of M approximate to 10(-3) M-circle dot yr(-1); and (2) an inner shell with R-in similar to 6.3 x 10(14) cm, T-dust similar to 500 - 105 K, and M similar to 3 x 10(-5) M-circle dot yr(-1). An additional population of big dust grains (radius a greater than or similar to 0.4 mm) with T-dust = 150-20 K and mass M-dust = (0.16 - 1.6) x 10(-3) (D/3 kpc)(2) M-circle dot can account for the observed submillimeter and millimeter flux excess. The mass of the envelope enclosed within R-out = 1.25 x 10(17) cm derived from SED modeling is similar to 1 (D/3 kpc)(2) M-circle dot. C1 CSIC, Dept Astrofis Mol & Infrarroja, Inst Estructura Mat, Madrid, Spain. WM Keck Observ, Kamuela, HI USA. CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. Univ Complutense Madrid, Dept Astrofis, Madrid, Spain. Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA USA. RP Contreras, CS (reprint author), CSIC, Dept Astrofis Mol & Infrarroja, Inst Estructura Mat, Madrid, Spain. RI Sanchez-Contreras, Carmen/N-3718-2015; Gil de Paz, Armando/J-2874-2016 OI Sanchez-Contreras, Carmen/0000-0002-6341-592X; Gil de Paz, Armando/0000-0001-6150-2854 NR 61 TC 14 Z9 14 U1 0 U2 2 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X EI 1538-4357 J9 ASTROPHYS J JI Astrophys. J. PD FEB 20 PY 2007 VL 656 IS 2 BP 1150 EP 1166 DI 10.1086/510480 PN 1 PG 17 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 138BG UT WOS:000244336900046 ER PT J AU Liu, Y Vander Wal, RL Khabashesku, VN AF Liu, Yu Vander Wal, Randy L. Khabashesku, Valery N. TI Functionalization of carbon nano-onions by direct fluorination SO CHEMISTRY OF MATERIALS LA English DT Article ID ROOM-TEMPERATURE; ARC-DISCHARGE; NANOTUBES; DIAMOND; NANOPARTICLES; COMPOSITES; PARTICLES; SURFACE; GROWTH AB Carbon nano-onions (CNO) are made of concentric fullerene-like shells and range from double- and triple- to multilayered structures. They remain the least studied allotrope of carbon yet. In the present study, a one-step process for functionalization of CNO (50-100 nm diameter) by addition of fluorine through direct fluorination at variable temperatures is reported. The reactions of CNO at three different temperatures, 350, 410, and 480 degrees C, yield fluorinated nano-onions (F-NO) of approximately C10.1F, C3.3F, and C2.3F stoichiometry, respectively, representing a new family of nanoscale fluorocarbon materials. The F-NO were characterized by a set of materials characterization methods including FTIR, Raman, UV-vis, and X-ray photoelectron spectroscopy, scanning (SEM) and transmission electron microscopy (TEM), X-ray diffraction, and thermal gravimetric analysis. SEM and TEM images show that even after breaking of the graphene layers in CNO by fluorine, the F-NO products retain the spherical onion-shaped morphology. The subsequent defluorination of F-NO by hydrazine treatment results in remarkable "healing" of broken graphene layers which rejoin within the sphere to substantially restore the CNO microstructure. In comparison with pristine CNO, fluorinated nano-onions show dramatically improved solubility in organic solvents, e.g., alcohols and DMF, enabling their processing for lubricating coatings, paints, nanocomposites, and biomedical applications. C1 Rice Univ, Dept Chem, Houston, TX 77005 USA. Rice Univ, Richard E Smalley Inst Nanosclae Sci & Technol, Houston, TX 77005 USA. NASA, Natl Ctr Micrograv Res, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Khabashesku, VN (reprint author), Rice Univ, Dept Chem, 6100 Main St, Houston, TX 77005 USA. EM khval@rice.edu NR 41 TC 57 Z9 61 U1 5 U2 56 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0897-4756 J9 CHEM MATER JI Chem. Mat. PD FEB 20 PY 2007 VL 19 IS 4 BP 778 EP 786 DI 10.1021/cm062177j PG 9 WC Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA 135OB UT WOS:000244161800020 ER PT J AU Tang, L Baeder, JD AF Tang, Lei Baeder, James D. TI Adaptive Euler simulations of airfoil-vortex interaction SO INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS LA English DT Article DE grid redistribution; vortex preservation; shock-vortex interaction; airfoil-vortex interaction; geometry conservation law ID FINITE-DIFFERENCE SCHEMES; GRID REDISTRIBUTION; COMPUTATIONS; ROTOR AB A grid redistribution method is used together with an improved spatially third-order accurate Euler solver to improve the accuracy of direct Enter simulations of airfoil-vortex interaction. The presented numerical results of two airfoil-vortex interaction cases indicate that with combination of the two methods, the numerical diffusion of vorticity inherent in the direct Euler simulations is drastically reduced without increasing the number of grid points. With some extra works due to grid redistribution, the predicted vortex structure is well preserved after a long convection and much sharper acoustic wave front resulting from airfoil-vortex interaction is captured. Copyright (c) 2006 John Wiley & Sons, Ltd. C1 ZONA Technol Inc, Scottsdale, AZ 85258 USA. Univ Maryland, Dept Aerosp Engn, College Pk, MD 20742 USA. RP Tang, L (reprint author), NASA, Ames Res Ctr, UARC, MS 215-1,Bldg 215, Moffett Field, CA 94035 USA. EM ltang@merlin.arc.nasa.gov; baeder@eng.umd.edu NR 24 TC 4 Z9 4 U1 0 U2 4 PU JOHN WILEY & SONS LTD PI CHICHESTER PA THE ATRIUM, SOUTHERN GATE, CHICHESTER PO19 8SQ, W SUSSEX, ENGLAND SN 0271-2091 J9 INT J NUMER METH FL JI Int. J. Numer. Methods Fluids PD FEB 20 PY 2007 VL 53 IS 5 BP 777 EP 792 DI 10.1002/fld.1306 PG 16 WC Computer Science, Interdisciplinary Applications; Mathematics, Interdisciplinary Applications; Mechanics; Physics, Fluids & Plasmas SC Computer Science; Mathematics; Mechanics; Physics GA 130MU UT WOS:000243804500004 ER PT J AU Freund, F Sornette, D AF Freund, F. Sornette, D. TI Electro-magnetic earthquake bursts and critical rupture of peroxy bond networks in rocks SO TECTONOPHYSICS LA English DT Article; Proceedings Paper CT 1st General Meeting of the European-Geosciences-Union CY APR 25-30, 2004 CL Nice, FRANCE SP European Geosci Union DE critical earthquake; electro-magnetic precursors; peroxy bonds; fractoemissions; crust damage ID TIME-TO-FAILURE; NOMINALLY ANHYDROUS MINERALS; SELF-ORGANIZED CRITICALITY; DISCRETE SCALE-INVARIANCE; CHI-CHI EARTHQUAKE; ELECTRICAL-CONDUCTIVITY; MAGNESIUM-OXIDE; IGNEOUS ROCKS; STRESS ACCUMULATION; SOUTHERN-CALIFORNIA AB We propose a mechanism for the low frequency electromagnetic emissions and other electromagnetic and electric phenomena which have been associated with earthquakes. The mechanism combines the critical earthquake concept and the concept of crust acting as a charging electric battery under increasing stress. The electric charges are released by activation of dormant charge carriers in the oxygen anion sublattice, called peroxy bonds or positive hole pairs (PHP), where a PHP represents an O3X/(OO)\YO3 with X,Y=Si4+ Al3+,..., i.e. O- in a matrix of O2- of silicates. We propose that PHP are activated by plastic deformations during the slow cooperative build-up of stress and the increasingly correlated damage culminating in a large "critical" earthquake. Recent laboratory experiments indeed show that stressed rocks form electric batteries which can release their charge when a conducting path closes the equivalent electric circuit. We conjecture that the intermittent and erratic occurrences of EM signals are a consequence of the progressive build-up of the battery charges in the Earth crust and of their release when crack networks percolate through the stressed rock volumes, providing a conductive pathway for the battery currents to discharge. EM signals are thus expected close to the rupture, either slightly before or after, that is, when percolation is most favored. The proposed mechanism should be relevant for the broader understanding of fractoemissions. (c) 2006 Elsevier B.V. All rights reserved. C1 ETH, Swiss Fed Inst Technol, DMTEC, CH-8032 Zurich, Switzerland. San Jose State Univ, Dept Phys, San Jose, CA 95192 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. SETI Inst, Carl Sagan Ctr, Mountain View, CA 94043 USA. Univ Calif Los Angeles, Inst Geophys & Planetary Phys, Los Angeles, CA 90095 USA. Univ Calif Los Angeles, Dept Earth & Space Sci, Los Angeles, CA 90024 USA. RP Sornette, D (reprint author), ETH, Swiss Fed Inst Technol, DMTEC, CH-8032 Zurich, Switzerland. EM ffreund@mail.arc.nasa.gov; dsornette@ethz.ch NR 161 TC 19 Z9 20 U1 0 U2 7 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0040-1951 J9 TECTONOPHYSICS JI Tectonophysics PD FEB 20 PY 2007 VL 431 IS 1-4 BP 33 EP 47 DI 10.1016/j.tecto.2006.05.032 PG 15 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 142IQ UT WOS:000244643300005 ER PT J AU Freund, F da Silva, MAS Lau, BWS Takeuchi, A Jones, HH AF Freund, Friedemann da Silva, Manuel A. Salgueiro Lau, Bobby W. S. Takeuchi, Akihiro Jones, Hollis H. TI Electric currents along earthquake faults and the magnetization of pseudotachylite veins SO TECTONOPHYSICS LA English DT Article; Proceedings Paper CT 1st General Meeting of the European-Geosciences-Union CY APR 25, 2004 CL Vienna, AUSTRIA SP European Geosci Union DE earthquake physics; friction melt; magnetization; pseudotachylite; electric currents ID CONTINENTAL-CRUST; THEORETICAL CONSIDERATIONS; CONDUCTIVITY; ROCKS; PRESSURE; EMISSIONS; FRACTURE; ORIGIN; TEMPERATURE; PRECURSORS AB Pseudotacbylites occur in the form of thin glassy veins quenched from frictional melts along the fault planes of major earthquakes. They contain finely grained magnetite and often exhibit a high natural remanent magnetization (NRM). High NRM values imply strong local electric currents. These currents must persist for some time, while the pseudotachylite veins cool through the Curie temperature of magnetite around 580 degrees C. There is no generally accepted theory explaining how such powerful, persistent currents may be generated along the fault plane. Data presented here suggest the activation of electronic charge carriers, which are present in igneous rocks in a dormant, inactive form. These charge carriers can be "awakened" by the application of stress. They are electrons and defect electrons, also known as positive holes or p-holes for short. While p-holes are capable of spreading out of the stressed rock volume into adjacent p-type conductive unstressed rocks, electrons require a connection to the hot, n-type conductive lower crust. However, as long as the (downward) electron flow is not connected, the circuit is not closed. Hence, with the outflow of p-holes impeded, no current can be sustained. This situation is comparable to that of a charged battery where one pole remains unconnected. The friction melt that forms coseismically during rupture, provides a conductive path downward, which closes the circuit. This allows a current to flow along the fault plane. Extrapolating from laboratory data, every km(3) of stressed igneous rocks adjacent to the fault plane can deliver 10(3)-10(5) A. Hence, the current along the fault plane will not be limited by the number of charge carriers but more likely by the (electronic) conductivity of the cooling pseudotachylite vein. The sheet current will produce a magnetic field, whose vectors will lie in the fault plane and perpendicular to the flow direction. (c) 2006 Elsevier B.V. All rights reserved. C1 San Jose State Univ, Dept Phys, San Jose, CA 95192 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ Porto, Inst Fis Mat, P-687416900 Oporto, Portugal. Niigata Univ, Dept Chem, Niigata 9502181, Japan. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Freund, F (reprint author), San Jose State Univ, Dept Phys, San Jose, CA 95192 USA. EM ffreund@mail.arc.nasa.gov RI Takeuchi, Akihiro/E-8960-2011; OI Salgueiro da Silva, Manuel/0000-0002-7611-6056 NR 51 TC 9 Z9 10 U1 0 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0040-1951 J9 TECTONOPHYSICS JI Tectonophysics PD FEB 20 PY 2007 VL 431 IS 1-4 BP 131 EP 141 DI 10.1016/j.tecto.2006.05.039 PG 11 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 142IQ UT WOS:000244643300013 ER PT J AU Ouzounov, D Liu, DF Kang, CL Cervone, G Kafatos, M Taylor, P AF Ouzounov, Dimitar Liu, Defu Kang Chunli Cervone, Guido Kafatos, Menas Taylor, Patnick TI Outgoing long wave radiation variability from IR satellite data prior to major earthquakes SO TECTONOPHYSICS LA English DT Article; Proceedings Paper CT 1st General Meeting of the European-Geosciences-Union CY APR 25, 2004 CL Vienna, AUSTRIA SP European Geosci Union DE earthquake dynamics and mechanism; remote sensing and electromagnetic phenomena; satellite thermal image; creep and deformation ID SEISMICALLY ACTIVE AREAS; THERMAL ANOMALIES; SURFACE; KAMCHATKA AB Our analysis of the continuous outgoing long wave earth radiation (OLR) indicates anomalous variations prior to a number of medium to large earthquakes. The most recent analysis of OLR is from the M9.0 Sumatra Andaman Islands mega trust event. We compared the reference fields for December 2001 to 2004 and found OLR anomalous values, > 80 W/m(2), (2 sigma) within the epicentral area on Dec 21, 2004, 5 days before the event. We used the NOAAAR daily (one degree) and monthly (two and half degree) gridded data to differentiate between the global and seasonal variability and the transient local anomalies. The cause of such anomalies is not fully understood; one possible explanation is the existence of thermal outgoing radiation as a result of near ground air ionization and latent heat change due to change of air humidity and temperature. This phenornetion is hypothesized to be part of a relationship between tectonic stresses, electrochemical and thermodynamic processes in the atmosphere and increasing mid IR flux, all part of a family of electromagnetic (EM) phenomena related to earthquake activity. The time scale of the observed variations is a few weeks before the onset of the seismic event. In comparison with several years of data, the observed time-series preceding the earthquake had unusually high OLR. The OLR anomaly corresponds to a large area of ground coverage and coincides with the main epicentral zone. The significance of these observations is explored using data from most recent East Asian earthquake swarm of December 2004 and three other earthquakes. (c) 2006 Elsevier B.V. All rights reserved. C1 NASA, Goddard Space Flight Ctr, SSAI, Greenbelt, MD 20771 USA. China Earthquake Adm, Ctr Anal & Predict, Beijing 100036, Peoples R China. George Mason Univ, CEOSR, Fairfax, VA 22030 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Ouzounov, D (reprint author), NASA, Goddard Space Flight Ctr, SSAI, Greenbelt, MD 20771 USA. EM Ouzounov@core2.gsfe.nasa.gov RI Taylor, Patrick/D-4707-2012; OI Taylor, Patrick/0000-0002-1212-9384; Cervone, Guido/0000-0002-6509-0735 NR 24 TC 77 Z9 93 U1 2 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0040-1951 J9 TECTONOPHYSICS JI Tectonophysics PD FEB 20 PY 2007 VL 431 IS 1-4 BP 211 EP 220 DI 10.1016/j.tecto.2006.05.042 PG 10 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 142IQ UT WOS:000244643300018 ER PT J AU Suzuki, M Yamada, T Yang, CY AF Suzuki, Makoto Yamada, Toshishige Yang, Cary Y. TI Monte Carlo simulation of scanning electron microscopy bright contrast images of suspended carbon nanofibers SO APPLIED PHYSICS LETTERS LA English DT Article ID NANOTUBES AB The authors present a Monte Carlo study of previously observed bright contrast from carbon nanofibers suspended over the underlying substrate using scanning electron microscopy (SEM). The analysis shows that the origin of the bright contrast is mainly the increase in the secondary electron signal from the substrate when a gap between the nanofiber and substrate exists. The SEM signal dependence on the gap height is well reproduced by Monte Carlo simulation as well as a derived analytical expression. The bright contrast prevails when the SEM beam size is much smaller than the nanofiber diameter. (c) 2007 American Institute of Physics. C1 Santa Clara Univ, Ctr Nanostruct, Santa Clara, CA 95053 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Suzuki, M (reprint author), Santa Clara Univ, Ctr Nanostruct, 500 El Camino Real, Santa Clara, CA 95053 USA. EM m1suzuki@scu.edu RI Yamada, Toshishige/E-7834-2012 OI Yamada, Toshishige/0000-0001-7145-9212 NR 14 TC 16 Z9 16 U1 0 U2 2 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD FEB 19 PY 2007 VL 90 IS 8 AR 083111 DI 10.1063/1.2450655 PG 3 WC Physics, Applied SC Physics GA 139GP UT WOS:000244420600077 ER PT J AU Rossow, WB Pearl, C AF Rossow, William B. Pearl, Cindy TI 22-Year survey of tropical convection penetrating into the lower stratosphere SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID OPTICALLY THIN; LIFE-CYCLE; TROPOPAUSE; CLOUDS; HUMIDITY; DEEP; TROPOSPHERE; ISCCP; AIR AB A 22-year survey of tropical convection penetrating into the stratosphere has been conducted using special subsets of the International Satellite Cloud Climatology Project cloud data set. In addition to refined information about the geographic distribution of penetrating convective systems, these results show that penetrating convection occurs predominantly in the larger, organized, mesoscale convective systems, whereas smaller, unorganized convective systems rarely penetrate. Durations of penetrating events are longest for the largest systems, hurricanes and typhoons, generally exceeding one day. C1 CUNY City Coll, Dept Elect Engn, New York, NY 10031 USA. Columbia Univ, Goddard Inst Space Studies, New York, NY 10025 USA. RP Rossow, WB (reprint author), CUNY City Coll, Dept Elect Engn, Steinman Hall T-107, New York, NY 10031 USA. EM wbrossow@ccny.cuny.edu RI Rossow, William/F-3138-2015 NR 22 TC 36 Z9 36 U1 1 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD FEB 17 PY 2007 VL 34 IS 4 AR L04803 DI 10.1029/2006GL028635 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 138KS UT WOS:000244362100004 ER PT J AU Takemura, T Kaufman, YJ Remer, LA Nakajima, T AF Takemura, Toshihiko Kaufman, Yoram J. Remer, Lorraine A. Nakajima, Teruyuki TI Two competing pathways of aerosol effects on cloud and precipitation formation SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID CLIMATE RESPONSE; MODEL; SIMULATION; RADIATION; POLLUTION; ALBEDO; SMOKE AB Aerosols may influence cloud formation through two pathways: One is the effect on cloud microphysics by forming smaller and more numerous cloud droplets reducing precipitation and consequently enhancing cloud lifetime. The second is referred to as the aerosol dynamic-hydrological effect in which the aerosol direct, semi-direct, and indirect effects can modulate atmospheric radiation, which perturbs atmospheric circulation, leading to redistributions of clouds and precipitation. Here this study examines climate sensitivities using a general circulation model coupled with an aerosol transport-radiation model. The model is run first with prescribed meteorology in order to isolate the cloud microphysical effect. It is run in a separate experiment with internally generated meteorology that includes dynamic-hydrological effect as the aerosols modify clouds and interact with the radiation. We find in some regions that the dynamic-hydrological effect in the free model runs counteracts the microphysical effects seen in the prescribed runs. C1 Kyushu Univ, Appl Mech Res Inst, Fukuoka 8168580, Japan. Univ Tokyo, Ctr Climate Syst Res, Chiba 2778568, Japan. NASA, Goddard Space Flight Ctr, Lab Atmospheres, Greenbelt, MD 20771 USA. RP Takemura, T (reprint author), Kyushu Univ, Appl Mech Res Inst, 6-1 Kasugakouen, Fukuoka 8168580, Japan. EM toshi@riam.kyushu-u.ac.jp RI Takemura, Toshihiko/C-2822-2009; Nakajima, Teruyuki/H-2370-2013; Kyushu, RIAM/F-4018-2015; U-ID, Kyushu/C-5291-2016 OI Takemura, Toshihiko/0000-0002-2859-6067; Nakajima, Teruyuki/0000-0002-9042-504X; NR 20 TC 13 Z9 14 U1 0 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD FEB 17 PY 2007 VL 34 IS 4 AR L04802 DI 10.1029/2006GL028349 PG 5 WC Geosciences, Multidisciplinary SC Geology GA 138KS UT WOS:000244362100003 ER PT J AU Litvak, ML Mitrofanov, IG Kozyrev, AS Sanin, AB Tretyakov, VI Boynton, WV Kelly, NJ Hamara, D Saunders, RS AF Litvak, M. L. Mitrofanov, I. G. Kozyrev, A. S. Sanin, A. B. Tretyakov, V. I. Boynton, W. V. Kelly, N. J. Hamara, D. Saunders, R. S. TI Long-term observations of southern winters on Mars: Estimations of column thickness, mass, and volume density of the seasonal CO2 deposit from HEND/Odyssey data SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID HEND INSTRUMENT ONBOARD; GENERAL-CIRCULATION MODEL; X-RAY SPECTROMETER; ODYSSEY SPACECRAFT; MARTIAN SURFACE; NEUTRON MEASUREMENTS; GLOBAL DISTRIBUTION; CARBON-DIOXIDE; NEAR-SURFACE; SNOW DEPTH AB [ 1] In this paper, we have analyzed neutron spectroscopy data gathered by the High Energy Neutron Detector (HEND) instrument on board Mars Odyssey for two Martian years of orbital mapping. We focused on the observations of the Martian southern seasonal cap for this period of time. Nuclear methods based on numerical modeling allow us to derive an estimation of the distribution of CO2 frost column density and mass from the temporal variations of neutron flux between summer and winter seasons. We have estimated the seasonal behavior of both the column density and mass of CO2 frost. Comparison between two Martian years revealed minor (< 10%) interannual variations of CO2 thickness at the south pole during the middle of southern winter. It was found that maximal mass of the southern seasonal cap is achieved at L-s = 160 degrees and is equal to 6.6 +/- 0.6 x 10(15) kg. We found that this result corresponds well with previous HEND results, NASA Ames GCM predictions, Gamma Ray Spectrometer estimates, and estimations from gravity models based on MGS and Mars Odyssey tracking data. In our analysis, we also compared to processed MOLA data ( linear thicknesses of snow depths) to measure the value of the volume density of the Southern seasonal cap, and we found that it may vary in the range 400 - 1250 kg/m(3). C1 Space Res Inst, Moscow 117997, Russia. Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. NASA Headquarters, Washington, DC 20514 USA. RP Litvak, ML (reprint author), Space Res Inst, Profsojuznaya St 84-32, Moscow 117997, Russia. EM max@cgrsmx.iki.rssi.ru NR 42 TC 5 Z9 5 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9097 EI 2169-9100 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD FEB 17 PY 2007 VL 112 IS E3 AR E03S13 DI 10.1029/2006JE002832 PG 10 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 138OX UT WOS:000244373200001 ER PT J AU Harder, SL Shindell, DT Schmidt, GA Brook, EJ AF Harder, S. L. Shindell, D. T. Schmidt, G. A. Brook, E. J. TI A global climate model study of CH4 emissions during the Holocene and glacial-interglacial transitions constrained by ice core data SO GLOBAL BIOGEOCHEMICAL CYCLES LA English DT Article ID GENERAL-CIRCULATION MODEL; SEA-SURFACE TEMPERATURE; ATMOSPHERIC METHANE; TROPOSPHERIC OZONE; CARBON-MONOXIDE; GODDARD-INSTITUTE; ANTHROPOGENIC EMISSIONS; NATURAL WETLANDS; CHEMISTRY MODEL; SPACE AB [ 1] Ice core records show atmospheric methane mixing ratio and interpolar gradient varying with climate. Changes in wetland sources have been implicated as the basis for this observed variation in the record, but more recently, modeling studies suggest that changes in the CH4 sink resulting from changes in sea surface temperature (SST) and emissions of other volatile organic carbon (VOC) compounds by vegetation must also be considered. We use the Goddard Institute for Space Studies (GISS) General Circulation Model (GCM) with the GISS Tropospheric Chemistry Model to study the response of the methane mixing ratio to source changes during the Holocene and also to a changing chemical sink during glacial-interglacial transitions. We combine model results with ice core data to demonstrate a method that provides constraints on changes in northern and tropical methane sources. Results show that within the Holocene, changes in the atmospheric methane mixing ratio and latitudinal gradient are not linear with respect to changing methane emissions. Tropical and northern emissions varied from preindustrial levels by as much as 38% and 15%, respectively, within the Holocene. At glacial-interglacial transitions the methane mixing ratio is sensitive to changes in both VOC and tropical methane emissions and the sensitivity also depends strongly on the assumed SST shift. Our findings suggest that changes in the ice core methane record are likely the result of changes in both the source and the sink. Changes in the sink become especially important when changes in methane mixing ratio and/or climate are large. C1 Washington State Univ, Sch Earth & Environm Sci, Vancouver, WA 98686 USA. Oregon State Univ, Dept Geosci, Corvallis, OR 97331 USA. NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Columbia Univ, Ctr Climate Syst Res, New York, NY 10025 USA. RP Harder, SL (reprint author), Washington State Univ, Sch Earth & Environm Sci, 14204 NE Salmon Creek, Vancouver, WA 98686 USA. EM harders@vancouver.wsu.edu; dshindell@giss.nasa.gov; gschmidt@giss.nasa.gov; brooke@geo.oregonstate.edu RI Shindell, Drew/D-4636-2012; Schmidt, Gavin/D-4427-2012 OI Schmidt, Gavin/0000-0002-2258-0486 NR 61 TC 15 Z9 15 U1 3 U2 12 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0886-6236 EI 1944-9224 J9 GLOBAL BIOGEOCHEM CY JI Glob. Biogeochem. Cycle PD FEB 16 PY 2007 VL 21 IS 1 AR GB1011 DI 10.1029/2005GB002680 PG 13 WC Environmental Sciences; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Geology; Meteorology & Atmospheric Sciences GA 138LD UT WOS:000244363200001 ER PT J AU Fan, JW Zhang, RY Li, GH Tao, WK Li, XW AF Fan, Jiwen Zhang, Renyi Li, Guohui Tao, Wei-Kuo Li, Xiaowen TI Simulations of cumulus clouds using a spectral microphysics cloud-resolving model SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID CONVECTIVE CLOUDS; DETAILED MICROPHYSICS; ATMOSPHERIC AEROSOLS; AXISYMMETRICAL MODEL; CONDENSATION NUCLEI; RAIN PRODUCTION; ICE INITIATION; ENSEMBLE MODEL; NOX PRODUCTION; PART I AB We have investigated the effects of aerosols on the development of cumulus clouds using a two- dimensional spectral- bin cloud- resolving model. A convective cloud event occurring on 24 August 2000 in Houston, Texas, was simulated and the model results were compared with available radar and rain gauge measurements. Simulations assuming different aerosol chemical compositions were conducted to examine the impacts on cumulus development. The cloud microphysical and macrophysical properties changed considerably with the aerosol chemical properties. With varying the aerosol composition from only (NH4)(2)SO4, (NH4)(2)SO4 with soluble organics, to (NH4) 2SO4 with slightly soluble organics, the number of activated aerosols in cloud decreased accordingly, leading to a decrease in the cloud droplet number concentration and an increase in the droplet size. Increasing activated aerosols resulted in the increase of ice crystal formation by homogeneous freezing, more extensive riming, lower supersaturation (S-w and S-ice), less efficient growth of graupel, and more melting precipitation. Ice microphysical processes were more sensitive to the changes of aerosol chemical properties than the warm rain processes. The changes in macrophysical properties were more evident: The increase of activated aerosols resulted in longer cell lifetime, larger cell size, stronger secondary convective cell, and more accumulated precipitation. The simulation with the aerosol composition of (NH4) 2SO4 with slightly soluble organics and an activation scheme of a reformulation of the Kohler theory to include the effect of slightly soluble organics and soluble HNO3 agreed well with the observations. The simulation captured the major convective cell observed from the field measurements. The predicted convective cell intensity, cell size, cell lifetime, and accumulated rain were in agreement with the observations. C1 Texas A&M Univ, Dept Atmospher Sci, College Stn, TX 77843 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Fan, JW (reprint author), Texas A&M Univ, Dept Atmospher Sci, College Stn, TX 77843 USA. EM zhang@ariel.met.tamu.edu RI Zhang, Renyi/A-2942-2011; Fan, Jiwen/E-9138-2011 NR 53 TC 43 Z9 43 U1 1 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD FEB 16 PY 2007 VL 112 IS D4 AR D04201 DI 10.1029/2006JD007688 PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 138LG UT WOS:000244363500003 ER PT J AU Newsom, HE Crumpler, LS Reedy, RC Petersen, MT Newsom, GC Evans, LG Taylor, GJ Keller, JM Janes, DM Boynton, WV Kerry, KE Karunatillake, S AF Newsom, Horton E. Crumpler, Larry S. Reedy, Robert C. Petersen, Michael T. Newsom, Gary C. Evans, Larry G. Taylor, G. Jeffrey Keller, John M. Janes, Daniel M. Boynton, William V. Kerry, Kris E. Karunatillake, Suniti TI Geochemistry of Martian soil and bedrock in mantled and less mantled terrains with gamma ray data from Mars Odyssey SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Review ID THERMAL EMISSION SPECTROMETER; OLYMPUS MONS AUREOLE; GUSEV CRATER; GLOBAL SURVEYOR; SPIRIT ROVER; HYDROTHERMAL ALTERATION; CHEMICAL-COMPOSITION; SYRTIS MAJOR; SURFACE-PROPERTIES; ACCRETION HISTORY AB [ 1] Surficial materials, including soil and dust, are abundant in the upper tens of centimeters of the Martian surface sensed by the Mars Odyssey Gamma Ray Spectrometer (GRS). Seven large areas (14% of the Martian surface) that represent possible compositional end-members were selected, including three regions heavily mantled with surficial materials. The selection process included mapping the ratio of exposed rocky terrain to surficial materials using high-resolution imagery. GRS data for H, Cl, Fe, Si, K, and Th were obtained for each area. The areas are chemically homogeneous within each area, given the spatial resolution and analytical uncertainty of the GRS data. However, substantial chemical differences exist among the areas, including the different mantled terrains, contrary to earlier assumptions that surficial materials are globally homogeneous due to aeolian mixing. The observed chemical differences among the areas may be due to variations in the protolith compositions, extent of alteration of the protolith regions, or post soil formation processes. The abundances of Cl, K, and Th in rockier ( but still soil-rich) areas such as Syrtis Major Planum can be explained by mixing between a soil with higher concentrations of Cl, K, and Th, similar to the abundances in the mantled terrains ( and some of the landing sites), and crustal rocks containing lower abundances of these elements, similar to Martian meteorites. C1 Univ New Mexico, Inst Meteorit, Albuquerque, NM 87131 USA. Univ New Mexico, Dept Earth & Planetary Sci, Albuquerque, NM 87131 USA. New Mexico Museum Nat Hist & Sci, Albuquerque, NM 87104 USA. Comp Sci Corp, Lanham, MD 20706 USA. Hawaii Inst Geophys & Planetol, Honolulu, HI 96822 USA. NASA, Astrobiol Inst, Honolulu, HI 96822 USA. Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. Cornell Univ, Dept Astron, Ithaca, NY 14853 USA. RP Newsom, HE (reprint author), Univ New Mexico, Inst Meteorit, MSC 3 2050, Albuquerque, NM 87131 USA. EM newsom@unm.edu RI Karunatillake, Suniti/A-5934-2009; OI Karunatillake, Suniti/0000-0001-9891-1432; Reedy, Robert/0000-0002-2189-1303 NR 112 TC 24 Z9 24 U1 4 U2 13 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9097 EI 2169-9100 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD FEB 16 PY 2007 VL 112 IS E3 AR E03S12 DI 10.1029/2006JE002680 PG 24 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 138OV UT WOS:000244373000001 ER PT J AU Zhang, H Dunlop, MW Zong, QG Fritz, TA Balogh, A Wang, Y AF Zhang, H. Dunlop, M. W. Zong, Q. -G. Fritz, T. A. Balogh, A. Wang, Y. TI Geometry of the high-latitude magnetopause as observed by Cluster SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID HIGH-ALTITUDE CUSP; INTERPLANETARY MAGNETIC-FIELD; BOUNDARY-LAYER; POLAR MAGNETOSPHERE; ENERGETIC ELECTRONS; LINE TOPOLOGY; EXTERIOR CUSP; RECONNECTION; PLASMA; REGION AB This investigation reveals the geometrical properties of the high-latitude boundaries surrounding the high-altitude cusp. These have been shown by recent studies to include the outer boundary between the magnetosheath and the cusp; the outer boundary between the magnetosheath and the high-latitude, closed field-line region of the dayside magnetosphere ( which we call the high-latitude trapping region ( HLTR)); and the inner boundaries on the equatorward and tailward edges of the high-altitude cusp region. We present a survey of the normal directions of the outer boundaries: between the magnetosheath and cusp in comparison to between the magnetosheath and the HLTR. This study is based on the magnetic field data set obtained by the Cluster quartet for a period during which the orbits passed through either the dayside cusp or the magnetopause on consecutive orbits. These initial results show some evidence of the control of cusp geometry by the IMF orientation and clear trends which are consistent with an indentation or at least a nonplanar geometry in the cusp-magnetosheath boundary for those cases which are clearly identified. The detailed geometry of all surrounding cusp boundaries, deduced from selected crossings in the data set, case by case, is also shown to support these findings and to address the issue of the identification of relative spacecraft location with respect to this highly dynamic region. C1 Boston Univ, Ctr Space Phys, Boston, MA 02215 USA. Rutherford Appleton Lab, Space Sci & Technol Dept, Div Space Sci, Chilton, England. Univ Massachusetts, Ctr Atmospher Res, Lowell, MA USA. Univ London Imperial Coll Sci & Technol, Blackett Lab, London, England. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Zhang, H (reprint author), Boston Univ, Ctr Space Phys, Boston, MA 02215 USA. EM zhang@bu.edu RI dunlop, malcolm/F-1347-2010 NR 26 TC 15 Z9 15 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD FEB 16 PY 2007 VL 112 IS A2 AR A02204 DI 10.1029/2006JA011774 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 138PZ UT WOS:000244376000001 ER PT J AU Murphy, TW Nordtvedt, K Turyshev, SG AF Murphy, T. W., Jr. Nordtvedt, K. Turyshev, S. G. TI Gravitomagnetic influence on gyroscopes and on the lunar orbit SO PHYSICAL REVIEW LETTERS LA English DT Article ID GRAVITY; RELATIVITY AB Gravitomagnetism-a motional coupling of matter analogous to the Lorentz force in electromagnetism-has observable consequences for any scenario involving differing mass currents. Examples include gyroscopes located near a rotating massive body and the interaction of two orbiting bodies. In the former case, the resulting precession of the gyroscope is often called "frame dragging" and is the principal measurement sought by the Gravity Probe-B experiment. The latter case is realized in the Earth-Moon system, and the effect has in fact been confirmed via lunar laser ranging to approximately 0.1% accuracy-better than the anticipated accuracy of the Gravity-Probe-B result. This Letter shows the connection between these seemingly disparate phenomena by employing the same gravitomagnetic term in the equation of motion to obtain both gyroscopic precession and modification of the lunar orbit. C1 Univ Calif San Diego, La Jolla, CA 92093 USA. Northwest Anal, Bozeman, MT 59715 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Murphy, TW (reprint author), Univ Calif San Diego, 9500 Gilman Dr, La Jolla, CA 92093 USA. EM tmurphy@physics.ucsd.edu NR 14 TC 36 Z9 37 U1 0 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD FEB 16 PY 2007 VL 98 IS 7 AR 071102 DI 10.1103/PhysRevLett.98.071102 PG 4 WC Physics, Multidisciplinary SC Physics GA 136UT UT WOS:000244250300015 PM 17359012 ER PT J AU Short, JW Irvine, GV Mann, DH Maselko, JM Pella, JJ Lindeberg, MR Payne, JR Driskell, WB Rice, SD AF Short, Jeffrey W. Irvine, Gail V. Mann, Daniel H. Maselko, Jacek M. Pella, Jerome J. Lindeberg, Mandy R. Payne, James R. Driskell, William B. Rice, Stanley D. TI Slightly weathered Exxon Valdez oil persists in Gulf of Alaska beach sediments after 16 years SO ENVIRONMENTAL SCIENCE & TECHNOLOGY LA English DT Article ID PRINCE-WILLIAM-SOUND; ANAEROBIC OXIDATION; SPILL; HYDROCARBONS; PETROLEUM; ENVIRONMENT; SHORELINES AB Oil stranded by the 1989 Exxon Valdez spill has persisted in subsurface sediments of exposed shores for 16 years. With annualized loss rates declining from similar to 68% yr(-1) prior to 1992 to similar to 4% yr(-1) after 2001, weathering processes are retarded in both sediments and residual emulsified oil ("oil mousse"), and retention of toxic polycyclic aromatic hydrocarbons is prolonged. The n-alkanes, typically very readily oxidized by microbes, instead remain abundant in many stranded emulsified oil samples from the Gulf of Alaska. They are less abundant in Prince William Sound samples, where stranded oil was less viscous. Our results indicate that, at some locations, remaining subsurface oil may persist for decades with little change. C1 NOAA, Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr, Auke Bay Lab, Juneau, AK 99801 USA. US Geol Survey, Alaska Sci Ctr, Anchorage, AK 99503 USA. Univ Alaska, Inst Art Biol, Fairbanks, AK 99775 USA. Paybe Environm Consultants, Encinitas, CA 92024 USA. RP Short, JW (reprint author), NOAA, Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr, Auke Bay Lab, 11305 Glacier Highway, Juneau, AK 99801 USA. EM Jeff.Short@noaa.gov NR 29 TC 74 Z9 75 U1 0 U2 26 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0013-936X J9 ENVIRON SCI TECHNOL JI Environ. Sci. Technol. PD FEB 15 PY 2007 VL 41 IS 4 BP 1245 EP 1250 DI 10.1021/es0620033 PG 6 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA 135NZ UT WOS:000244161600032 PM 17593726 ER PT J AU Sandmann, T Girardot, C Brehme, M Tongprasit, W Stolc, V Furlong, EEM AF Sandmann, Thomas Girardot, Charles Brehme, Marc Tongprasit, Waraporn Stolc, Viktor Furlong, Eileen E. M. TI A core transcriptional network for early mesoderm development in Drosophila melanogaster SO GENES & DEVELOPMENT LA English DT Article DE Twist; Dorsal; mesoderm; ChIP-on-chip; transcriptional network; temporal regulation ID NEUROGENIC GENE-EXPRESSION; WHOLE-GENOME ANALYSIS; FACTOR-BINDING-SITES; REGULATORY ELEMENTS; PATTERNING GENES; DORSAL GRADIENT; TWIST; EMBRYO; TARGET; MAP AB Embryogenesis is controlled by large gene-regulatory networks, which generate spatially and temporally refined patterns of gene expression. Here, we report the characteristics of the regulatory network orchestrating early mesodermal development in the fruitfly Drosophila, where the transcription factor Twist is both necessary and sufficient to drive development. Through the integration of chromatin immunoprecipitation followed by microarray analysis (ChIP-on-chip) experiments during discrete time periods with computational approaches, we identified > 2000 Twist-bound cis-regulatory modules (CRMs) and almost 500 direct target genes. Unexpectedly, Twist regulates an almost complete cassette of genes required for cell proliferation in addition to genes essential for morophogenesis and cell migration. Twist targets almost 25% of all annotated Drosophila transcription factors, which may represent the entire set of regulators necessary for the early development of this system. By combining in vivo binding data from Twist, Mef2, Tinman, and Dorsal we have constructed an initial transcriptional network of early mesoderm development. The network topology reveals extensive combinatorial binding, feed-forward regulation, and complex logical outputs as prevalent features. In addition to binary activation and repression, we suggest that Twist binds to almost all mesodermal CRMs to provide the competence to integrate inputs from more specialized transcription factors. C1 European Mol Biol Lab, D-69117 Heidelberg, Germany. NASA, Ames Res Ctr, Genome Res Facil, Moffett Field, CA 94035 USA. RP Furlong, EEM (reprint author), European Mol Biol Lab, D-69117 Heidelberg, Germany. EM furlong@embl.de RI Brehme, Marc/G-8697-2015; OI Girardot, Charles/0000-0003-4301-3920; Brehme, Marc/0000-0003-0694-331X; Furlong, Eileen/0000-0002-9544-8339 NR 72 TC 173 Z9 176 U1 0 U2 11 PU COLD SPRING HARBOR LAB PRESS, PUBLICATIONS DEPT PI WOODBURY PA 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2924 USA SN 0890-9369 J9 GENE DEV JI Genes Dev. PD FEB 15 PY 2007 VL 21 IS 4 BP 436 EP 449 DI 10.1101/gad.1509007 PG 14 WC Cell Biology; Developmental Biology; Genetics & Heredity SC Cell Biology; Developmental Biology; Genetics & Heredity GA 140ZM UT WOS:000244545500010 PM 17322403 ER PT J AU Davis, LM Thompson, DS Dean, CJ Pevzner, M Scott, JL Broadwater, ST Thompson, DW Southward, RE AF Davis, Luke M. Thompson, D. Scott Dean, C. J. Pevzner, M. Scott, J. L. Broadwater, S. T. Thompson, D. W. Southward, R. E. TI Silver-polyimide nanocomposite membranes: Macromolecular-matrix-mediated metallization of an aromatic, fluorinated polyimide yielding highly reflective films at low metal concentrations SO JOURNAL OF APPLIED POLYMER SCIENCE LA English DT Article DE composites; inorganic materials; polyimides ID SINGLE-STAGE SYNTHESIS; SOLAR SAIL MATERIAL; THERMAL-CONDUCTIVITY; POLYMERIC FILMS; SURFACES; DEPOSITION; PALLADIUM; REDUCTION; 2,2'-BIS(TRIFLUOROMETHYL)-4,4'-DIAMINOBIPHENYL; 2,2-BIS(TRIFLUOROMETHYL)-4,4-DIAMINOBIPHENYL AB Highly reflective, surface-metalized, flexible polyimide films were prepared by the incorporation of a soluble silver-ion complex, (hexafluoroacetylacetonato)silver(I) (AgHFA), into dimethylacetamide solutions of poly (amic acid) prepared from 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride and 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane. The thermal curing of solution-cast silver(I)-poly(amic acid) films to 300 degrees C led to cycloimidization of the amic acid with concomitant silver(I) reduction and the formation of a reflective, air-side-silvered surface at very low (2 wt % and 0.3 vol %) silver concentrations. The reflective surface evolved only when the cure temperature reached about 275 degrees C, although X-ray diffraction showed metallic silver in the hybrid film by 200 degrees C. After a maximum specular reflectivity greater than 80% was achieved for the 2 wt % silver film, the specular reflectivity diminished sharply with further heating at a constant temperature of 300 degrees C. Incorporating the AgHFA complex into the soluble, fully imidized form of poly{(1,3-dihydro-1,3-dioxo-2H-isoindole-2,5-diyl)[2,2,2-trifluoro-1-(trifluoromethyl)ethylidene](1,3-dihydro-1,3-dioxo-2H-isoindole-5,2-diyl)-1,4-phenyleneoxy-1,4-phenylene [2,2,2-trifluoro-1-(trifluoromethyl)ethylidene]-1,4-phenyleneoxy-1,4-phenylene} gave films that were 25% less reflective than those beginning with poly(amic acid). Though highly reflective, the films were not electrically conductive. The metalized membranes were thermally stable and maintained mechanical properties similar to those of the parent polyimide. Transmission electron microscopy revealed an air-side, near-surface layer of silver that was about 40 nm thick; the interior of the film had well-dispersed metal particles with diameters mostly less than 2 nm. The near-surface silver layer maintained its integrity because of physical entrapment of the metal nanoparticles beneath a thin layer of polyimide; that is, the practical adhesion of the metal layer was good. (c) 2006 Wiley Periodicals, Inc. C1 Coll William & Mary, Dept Chem, Williamsburg, VA 23187 USA. Coll William & Mary, Dept Biol, Williamsburg, VA 23187 USA. NASA, Langley Res Ctr, Adv Mat & Proc Branch, Hampton, VA 23681 USA. RP Thompson, DW (reprint author), Coll William & Mary, Dept Chem, Williamsburg, VA 23187 USA. EM dwthom@wm.edu NR 87 TC 9 Z9 10 U1 1 U2 10 PU JOHN WILEY & SONS INC PI HOBOKEN PA 111 RIVER ST, HOBOKEN, NJ 07030 USA SN 0021-8995 J9 J APPL POLYM SCI JI J. Appl. Polym. Sci. PD FEB 15 PY 2007 VL 103 IS 4 BP 2409 EP 2418 DI 10.1002/app.25384 PG 10 WC Polymer Science SC Polymer Science GA 119LN UT WOS:000243013900044 ER PT J AU Ceberio, M Kreinovich, V Chopra, S Longpre, L Nguyen, HT Ludascher, B Baral, C AF Ceberio, Martine Kreinovich, Vladik Chopra, Sanjeev Longpre, Luc Nguyen, Hung T. Ludascher, Bertram Baral, Chitta TI Interval-type and affine arithmetic-type techniques for handling uncertainty in expert systems SO JOURNAL OF COMPUTATIONAL AND APPLIED MATHEMATICS LA English DT Article; Proceedings Paper CT 11th International Symposium on Scientific Computing, Computer Arithmetic, and Validated Numerics CY OCT 04-08, 2004 CL Fukuoka, JAPAN SP GAMM-IMACS DE interval computations; affine arithmetic; expert systems; fuzzy logic; geoinformatics; computer security AB Expert knowledge consists of statements S-j (facts and rules). The facts and rules are often only true with some probability. For example, if we are interested in oil, we should look at seismic data. If in 90% of the cases, the seismic data were indeed helpful in locating oil, then we can say that if we are interested in oil, then with probability 90% it is helpful to look at the seismic data. In more formal terms, we can say that the implication "if oil then seismic" holds with probability 90%. Another example: a bank A trusts a client B, so if we trust the bank A, we should trust B too; if statistically this trust was justified in 99% of the cases, we can conclude that the corresponding implication holds with probability 99%. If a query Q is deducible from facts and rules, what is the resulting probability p(Q) in Q? We can describe the truth of Q as a propositional formula F in terms of S-j, i.e., as a combination of statements S-j linked by operators like &, v, and -; computing p(Q) exactly is NP-hard, so heuristics are needed. Traditionally, expert systems use technique similar to straightforward interval computations: we parse F and replace each computation step with corresponding probability operation. Problem: at each step, we ignore the dependence between the intermediate results F-j; hence intervals are too wide. Example: the estimate for P(A v - A) is not 1. Solution: similar to affine arithmetic, besides P(F-j), we also compute P(F-j&F-i) (or P(F-jl ¢er dot center dot center dot & F-jd)), and on each step, use all combinations of 1 such probabilities to get new estimates. Results: e.g., P(A - A) is estimated as 1. (c) 2005 Elsevier B.V. All rights reserved. C1 Univ Texas, NASA, PanAmer Ctr Earth & Environm Studies, El Paso, TX 79968 USA. New Mexico State Univ, Dept Math, Las Cruces, NM 88003 USA. Univ Calif Davis, Dept Comp Sci, Davis, CA 95616 USA. Arizona State Univ, Dept Comp Sci & Engn, Tempe, AZ 85287 USA. RP Kreinovich, V (reprint author), Univ Texas, NASA, PanAmer Ctr Earth & Environm Studies, El Paso, TX 79968 USA. EM vladik@utep.edu NR 12 TC 8 Z9 8 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0377-0427 EI 1879-1778 J9 J COMPUT APPL MATH JI J. Comput. Appl. Math. PD FEB 15 PY 2007 VL 199 IS 2 SI SI BP 403 EP 410 DI 10.1016/j.cam.2005.08.030 PG 8 WC Mathematics, Applied SC Mathematics GA 130PV UT WOS:000243812400030 ER PT J AU Kreinovich, V Kosheleva, O Starks, SA Tupelly, K Dimuro, GP Costa, ACD Villaverde, K AF Kreinovich, Vladik Kosheleva, Olga Starks, Scott A. Tupelly, Kavitha Dimuro, Gracaliz P. da Rocha Costa, Antonio Carlos Villaverde, Karen TI From intervals to domains: Towards a general description of validated uncertainty, with potential applications to geospatial and meteorological data SO JOURNAL OF COMPUTATIONAL AND APPLIED MATHEMATICS LA English DT Article; Proceedings Paper CT 11th International Symposium on Scientific Computing, Computer Arithmetic, and Validated Numerics CY OCT 04-08, 2004 CL Fukuoka, JAPAN SP GAMM-IMACS DE interval computations; domains; geospatial data; meteorological data AB When physical quantities xi are numbers, then the corresponding measurement accuracy can be usually represented in interval terms, and interval computations can be used to estimate the resulting uncertainty in y = f{x(1)....,x(n)}. In some practical problems, we are interested in more complex structures such as functions, operators, etc. Examples: we may be interested in how the material strain depends on the applied stress, or in how a physical quantity such as temperature or velocity of sound depends on a 3-D point. For many such structures, there are ways to represent uncertainty, but usually, for each new structure, we have to perform a lot of complex analysis from scratch. It is desirable to come up with a general methodology that would automatically produce a natural description of validated uncertainty for all physically interesting situations (or at least for as many such situations as possible). In this paper, we describe the foundations for such a methodology; it turns out that this problem naturally leads to the technique of domains first introduced by D. Scott in the 1970s. In addition to general domain techniques, we also describe applications to geospatial and meteorological data. (c) 2006 Elsevier B.V. All rights reserved. C1 NASA, PanAmer Ctr Earth & Environm Studies, El Paso, TX 79968 USA. Univ Catolica Pelotas, Escola Informat, BR-96010000 Pelotas, RS, Brazil. New Mexico State Univ, Dept Comp Sci, Las Cruces, NM 88003 USA. RP Kreinovich, V (reprint author), NASA, PanAmer Ctr Earth & Environm Studies, El Paso, TX 79968 USA. EM vladik@utep.edu RI Dimuro, Gracaliz/G-5918-2012 NR 8 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0377-0427 EI 1879-1778 J9 J COMPUT APPL MATH JI J. Comput. Appl. Math. PD FEB 15 PY 2007 VL 199 IS 2 SI SI BP 411 EP 417 DI 10.1016/j.cam.2005.08.049 PG 7 WC Mathematics, Applied SC Mathematics GA 130PV UT WOS:000243812400031 ER PT J AU Kreinovich, V Longpre, L Starks, SA Xiang, G Beck, J Kandathi, R Nayak, A Ferson, S Hajagos, J AF Kreinovich, Vladik Longpre, Luc Starks, Scott A. Xiang, Gang Beck, Jan Kandathi, Raj Nayak, Asis Ferson, Scott Hajagos, Janos TI Interval versions of statistical techniques with applications to environmental analysis, bioinformatics, and privacy in statistical databases SO JOURNAL OF COMPUTATIONAL AND APPLIED MATHEMATICS LA English DT Article; Proceedings Paper CT 11th International Symposium on Scientific Computing, Computer Arithmetic, and Validated Numerics CY OCT 04-08, 2004 CL Fukuoka, JAPAN SP GAMM-IMACS DE intervals and probabilities; environmental analysis; bioinformatics; privacy; statistical databases AB In many areas of science and engineering, it is desirable to estimate statistical characteristics (mean, variance, covariance, etc.) under interval uncertainty. For example, we may want to use the measured values x(t) of a pollution level in a lake at different moments of time to estimate the average pollution level; however, we do not know the exact values x(t)-e.g., if one of the measurement results is 0, this simply means that the actual (unknown) value of x(t) can be. anywhere between 0 and the detection limit (DL). We must, therefore, modify the existing statistical algorithms to process such interval data. Such a modification is also necessary to process data from statistical databases, where, in order to maintain privacy, we only keep interval ranges instead of the actual numeric data (e.g., a salary range instead of the actual salary). Most resulting computational problems are NP-hard-which means, crudely speaking, that in general, no computationally efficient algorithm can solve all particular cases of the corresponding problem. In this paper, we overview practical situations in which computationally efficient algorithms exist: e.g., situations when measurements are very accurate, or when all the measurements are done with one (or few) instruments. As a case study, we consider a practical problem from bioinformatics: to discover the genetic difference between the cancer cells and the healthy cells, we must process the measurements results and find the concentrations c and h of a given gene in cancer and in healthy cells. This is a particular case of a general situation in which, to estimate states or parameters which are not directly accessible by measurements, we must solve a system of equations in which coefficients are only known with interval uncertainty. We show that in general, this problem is NP-hard, and we describe new efficient algorithms for solving this problem in practically important situations. (c) 2006 Elsevier B.V. All rights reserved. C1 Univ Texas, NASA, PACES, El Paso, TX 79968 USA. Appl Biomath, Setauket, NY 11733 USA. SUNY Stony Brook, Dept Ecol & Evolut, Stony Brook, NY 11794 USA. RP Kreinovich, V (reprint author), Univ Texas, NASA, PACES, El Paso, TX 79968 USA. EM vladik@utep.edu OI Hajagos, Janos/0000-0001-6251-9586 NR 9 TC 19 Z9 20 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0377-0427 J9 J COMPUT APPL MATH JI J. Comput. Appl. Math. PD FEB 15 PY 2007 VL 199 IS 2 SI SI BP 418 EP 423 DI 10.1016/j.cam.2005.07.041 PG 6 WC Mathematics, Applied SC Mathematics GA 130PV UT WOS:000243812400032 ER PT J AU Worden, HM Logan, JA Worden, JR Beer, R Bowman, K Clough, SA Eldering, A Fisher, BM Gunson, MR Herman, RL Kulawik, SS Lampel, MC Luo, M Megretskaia, IA Osterman, GB Shephard, MW AF Worden, H. M. Logan, J. A. Worden, J. R. Beer, R. Bowman, K. Clough, S. A. Eldering, A. Fisher, B. M. Gunson, M. R. Herman, R. L. Kulawik, S. S. Lampel, M. C. Luo, M. Megretskaia, I. A. Osterman, G. B. Shephard, M. W. TI Comparisons of Tropospheric Emission Spectrometer (TES) ozone profiles to ozonesondes: Methods and initial results SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID MAPPING SPECTROMETER; COLUMN OZONE; AURA MISSION; SATELLITE; TOMS; CLIMATOLOGY; CALIBRATION; RETRIEVALS; MODEL AB The Tropospheric Emission Spectrometer (TES) on the Earth Observing System (EOS)-Aura spacecraft measures global profiles of atmospheric ozone with vertical resolution of 6-7 km in the troposphere for the nadir view. For a first validation of TES ozone measurements we have compared TES-retrieved ozone profiles to ozonesondes from fall, 2004. In some cases the ozonesonde data are from dedicated launches timed to match the Aura overpass, while other comparisons are performed with routine data available from the Southern Hemisphere Additional Ozonesonde (SHADOZ) archive and World Ozone and Ultraviolet Data Center (WOUDC) data archives. We account for TES measurement sensitivity and vertical resolution by applying the TES-averaging kernel and constraint to the ozonesonde data before differencing the profiles. Overall, for V001 data, TES ozone profiles are systematically higher than sondes in the upper troposphere but compare well in the lower troposphere, with respect to estimated errors. These comparisons show that TES is able to detect relative variations in the coarse vertical structure of tropospheric ozone. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. Harvard Univ, Div Engn & Appl Sci, Cambridge, MA 02138 USA. AER, Lexington, MA USA. Raytheon Informat Solut, Pasadena, CA USA. RP Worden, HM (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91125 USA. EM helen.worden@jpl.nasa.gov RI Herman, Robert/H-9389-2012 OI Herman, Robert/0000-0001-7063-6424 NR 33 TC 100 Z9 101 U1 2 U2 7 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD FEB 15 PY 2007 VL 112 IS D3 AR D03309 DI 10.1029/2006JD007258 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 138LF UT WOS:000244363400002 ER PT J AU Warren-Rhodes, KA Rhodes, KL Liu, SJ Zhou, PJ McKay, CP AF Warren-Rhodes, Kimberley A. Rhodes, Kevin L. Liu, Shuangjiang Zhou, Peijin McKay, Christopher P. TI Nanoclimate environment of cyanobacterial communities in China's hot and cold hyperarid deserts SO JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES LA English DT Article ID SOIL-MOISTURE; COLONIZATION; TEMPERATURE; ANTARCTICA; ECOLOGY; REGION AB This paper analyzes linkages between lithic (lithobiontic, lithophytic) cyanobacterial community (LCC) abundance and climate across a wide range of environmental conditions and geographical distance in China's northwest region, an area containing some of the world's oldest, driest and most isolated deserts. In situ monitoring and long-term climate data show that extreme heterogeneity in liquid water availability characterizes the LCC environment across multiple spatial and temporal scales, with rainfall and snowmelt being the main moisture sources. Mean annual precipitation (MAP) primarily dictates LCC ecology across sites, but the interacting effects of temperature, moisture and light create a gradient of soil liquid water (ALW, 505 -1839 hr yr(-1)) and conditions suitable for metabolic activity (200 -922 hr yr(-1)) that also correlate with LCC abundance (0.99 +/- 0.2% to 12.6 +/- 1.8%). In situ soil temperatures indicate a minimum range of thermal tolerance for LCC in China's deserts of -23.8 degrees C to 53.8 degrees C. Through a comparison of similar available climate data for other deserts, we conclude that from a microbial physiological standpoint, although the hyperarid core of the Atacama Desert represents the driest nanoclimate environment recorded and the Dry Valleys in Antarctica represent the coldest desert conditions, it is the high-altitude deserts in the Qinghai-Tibetan Plateau that offer the coldest and driest recorded extremes for LCC on Earth. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ Hawaii, Dept Agr Forestry & Nat Resource Management, Hilo, HI 96720 USA. Chinese Acad Sci, Inst Microbiol, Beijing 100080, Peoples R China. RP Warren-Rhodes, KA (reprint author), NASA, Ames Res Ctr, Mail Stop 245-3, Moffett Field, CA 94035 USA. EM kwarren-rhodes@mail.arc.nasa.gov NR 30 TC 8 Z9 9 U1 0 U2 6 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-BIOGEO JI J. Geophys. Res.-Biogeosci. PD FEB 15 PY 2007 VL 112 IS G1 AR G01016 DI 10.1029/2006JG000260 PG 12 WC Environmental Sciences; Geosciences, Multidisciplinary SC Environmental Sciences & Ecology; Geology GA 138LJ UT WOS:000244363800001 ER PT J AU Melkonian, J Riha, SJ Robin, J Levine, E AF Melkonian, Jeffrey Riha, Susan J. Robin, Jessica Levine, Elissa TI Comparisons of measured stream flow with drainage and runoff simulated by a soil-vegetation-atmosphere transport model parameterized with GLOBE student data SO JOURNAL OF HYDROLOGY LA English DT Article DE drainage; GLOBE; runoff; simulation model; soil-vegetation-atmosphere; stream flow ID POTENTIAL EVAPORATION; DECIDUOUS FOREST; LEAF-AREA; EVAPOTRANSPIRATION; NITROGEN; SURFACE; COMPETITION; PHENOLOGY; CLIMATES; SCALE AB Predicting runoff and drainage from landscapes and correlating these with stream flow can be a powerful watershed management tool. We examined the feasibility of using runoff and drainage output of a simple soil-vegetation-atmosphere (SVAT) model as a predictor of monthly and daily changes in measured stream flow. Six watersheds in the eastern US were analyzed, located from approximately 35 degrees N to 43 degrees N. They ranged in area from 23 to 2463 km(2) and were 35-65% forested. The SVAT model was parameterized with weather, soils and phenotogical data largely obtained from a secondary school in each watershed that is participating in the Global Learning and Observations to Benefit the Environment (GLOBE) program. This program is a United States government science education effort promoting scientific inquiry in grades K-12 by providing protocols for collecting environmental data. Monthly measured stream flow and simulated runoff + drainage over a one year period were normalized to the largest value in that period and were compared using linear regression. Simulated monthly runoff + drainage explained between 37% and 76% of the variability in monthly stream flow. Changes in daily simulated runoff + drainage and measured stream flow depended on the simulated volumetric soil water content (theta(v)). At tow theta(v), Large precipitation events (> 20 mm) did not result in increased daily simulated runoff + drainage or measured stream flow. At high or saturating theta(v), large precipitation events resulted in increased daily simulated runoff + drainage followed by increased measured stream flow within two days. (c) 2006 Elsevier B.V. All rights reserved. C1 Cornell Univ, Dept Crop & Soil Sci, Ithaca, NY 14853 USA. Cornell Univ, Dept Earth & Atmospher Sci, Ithaca, NY 14853 USA. NASA, Goddard Space Flight Ctr, SSAI, Greenbelt, MD 20771 USA. RP Melkonian, J (reprint author), Cornell Univ, Dept Crop & Soil Sci, 1123 Bradfield Hall, Ithaca, NY 14853 USA. EM jjm11@cornell.edu NR 32 TC 0 Z9 0 U1 1 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-1694 J9 J HYDROL JI J. Hydrol. PD FEB 15 PY 2007 VL 333 IS 2-4 BP 214 EP 225 DI 10.1016/j.jhydrol.2006.08.008 PG 12 WC Engineering, Civil; Geosciences, Multidisciplinary; Water Resources SC Engineering; Geology; Water Resources GA 135NS UT WOS:000244160900004 ER PT J AU Parker, JK Payne, WA Cody, RJ Nesbitt, FL Stief, LJ Klippenstein, SJ Harding, LB AF Parker, James K. Payne, Walter A. Cody, Regina J. Nesbitt, Fred L. Stief, Louis J. Klippenstein, Stephen J. Harding, Lawrence B. TI Direct measurement and theoretical calculation of the rate coefficient for Cl+CH3 in the range from T=202-298 K SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID CORRELATED MOLECULAR CALCULATIONS; COLLISIONAL ENERGY-TRANSFER; UNIMOLECULAR RATE THEORY; GAUSSIAN-BASIS SETS; LOW-PRESSURE-LIMIT; RATE-CONSTANT; TEMPERATURE-DEPENDENCE; ATOMIC CHLORINE; REACTION COORDINATE; MASTER EQUATION AB The rate coefficient has been measured under pseudo-first-order conditions for the Cl + CH3 association reaction at T = 202, 250, and 298 K and P = 0.3-2.0 Torr helium using the technique of discharge-flow mass spectrometry with low-energy (12-eV) electron-impact ionization and collision-free sampling. Cl and CH3 were generated rapidly and simultaneously by reaction of F with HCl and CH4, respectively. Fluorine atoms were produced by microwave discharge in an approximately 1% mixture of F-2 in He. The decay of CH3 was monitored under pseudo-first-order conditions with the Cl-atom concentration in large excess over the CH3 concentration ([Cl](0)/[CH3](0) = 9-67). Small corrections were made for both axial and radial diffusion and minor secondary chemistry. The rate coefficient was found to be in the falloff regime over the range of pressures studied. For example, at T = 202 K, the rate coefficient increases from 8.4 x 10(-12) at P = 0.30 Torr He to 1.8 x 10(-11) at P = 2.00 Torr He, both in units of cm(3) molecule(-1) s(-1). A combination of ab initio quantum chemistry, variational transition-state theory, and master-equation simulations was employed in developing a theoretical model for the temperature and pressure dependence of the rate coefficient. Reasonable empirical representations of energy transfer and of the effect of spin-orbit interactions yield a temperature- and pressure-dependent rate coefficient that is in excellent agreement with the present experimental results. The high-pressure limiting rate coefficient from the RRKM calculations is k(2) = 6.0 x 10(-11) cm(3) molecule(-1) s(-1), independent of temperature in the range from 200 to 300 K. C1 NASA, Goddard Space Flight Ctr, Solar Syst Explorat Div, Greenbelt, MD 20771 USA. Sandia Natl Labs, Combust Res Facil, Livermore, CA 94551 USA. Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. RP Cody, RJ (reprint author), NASA, Goddard Space Flight Ctr, Solar Syst Explorat Div, Greenbelt, MD 20771 USA. EM Regina.J.Cody@nasa.gov RI Cody, Regina/D-5996-2013; OI Klippenstein, Stephen/0000-0001-6297-9187 NR 71 TC 8 Z9 9 U1 0 U2 7 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD FEB 15 PY 2007 VL 111 IS 6 BP 1015 EP 1023 DI 10.1021/jp066231v PG 9 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 133UO UT WOS:000244039600004 PM 17253663 ER PT J AU Sun, XH Yu, B Ng, G Meyyappan, M AF Sun, Xuhui Yu, Bin Ng, Garrick Meyyappan, M. TI One-dimensional phase-change nanostructure: Germanium telluride nanowire SO JOURNAL OF PHYSICAL CHEMISTRY C LA English DT Article ID OPTICAL-DATA STORAGE; X-RAY PHOTOEMISSION; THIN-FILMS; SWITCHING PHENOMENA; GETE; MEMORY; THRESHOLD AB High-quality nanowires of germanium telluride (GeTe), a one-dimensional chalcogenide phase-change nanostructure, were synthesized via thermal evaporation method under vapor-liquid-solid mechanism. The physical morphology, chemical composition, and crystal structure of the as-synthesized GeTe nanowires were investigated by scanning electron microscopy, energy dispersive X-ray spectroscopy, high-resolution transmission electron microscopy (HR-TEM), and X-ray photoemission spectroscopy. Through real-time TEM imaging of nanowire sample heated in an incrementally controllable heating system, the melting point of a single crystalline GeTe nanowire (similar to 40-80 nm diameter) is found to be significantly lower than that of its bulk counterpart (46% reduction, from 725 to 390 degrees C). The significant reduction in melting point makes one-dimensional phase-change chalcogenide nanowire a potential material for application in low-power high-density resistive switching nonvolatile data storage in which the thermal energy for material phase transition would be significantly reduced. C1 NASA, Ames Res Ctr, Ctr Nanotechnol, Moffett Field, CA 94035 USA. RP Sun, XH (reprint author), NASA, Ames Res Ctr, Ctr Nanotechnol, Moffett Field, CA 94035 USA. EM xsun@arc.nasa.gov; byu@arc.nasa.gov RI Sun, Xuhui /K-5689-2012 NR 31 TC 61 Z9 61 U1 3 U2 36 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1932-7447 J9 J PHYS CHEM C JI J. Phys. Chem. C PD FEB 15 PY 2007 VL 111 IS 6 BP 2421 EP 2425 DI 10.1021/jp0658804 PG 5 WC Chemistry, Physical; Nanoscience & Nanotechnology; Materials Science, Multidisciplinary SC Chemistry; Science & Technology - Other Topics; Materials Science GA 147LY UT WOS:000245005700011 ER PT J AU Geng, JH Wu, JF Jiang, SB Yu, JR AF Geng, Jihong Wu, Jianfeng Jiang, Shibin Yu, Jirong TI Efficient operation of diode-pumped single-frequency thulium-doped fiber lasers near 2 mu m SO OPTICS LETTERS LA English DT Article ID CW AB Efficient operation of diode-pumped single-frequency fiber lasers at wavelengths from 1740 to 2017 nm has been demonstrated by using a very short piece of newly developed single-mode active fiber, i.e., heavily thulium-doped germanate glass fiber. At 1893 nm, the single-frequency fiber laser has a pump threshold of 30 mW, a slope efficiency of 35%, and maximum output power of 50 mW with respect to the launched power of single-mode pump diodes at 805 run. To the best of our knowledge, this is the highest lasing efficiency achieved in single-frequency fiber lasers operating near 2 mu m. Frequency noise of the single-frequency fiber laser at 1893 nm has been characterized and compared with that of single-frequency fiber lasers at 1 and 1.55 mu m. (c) 2007 Optical Society of America. C1 NP Photon Inc, Tucson, AZ 85747 USA. NASA, Langley Res Ctr, Hampton, VA 22681 USA. RP Geng, JH (reprint author), NP Photon Inc, 9030 S Rita Rd, Tucson, AZ 85747 USA. EM geng@npphotonics.com NR 10 TC 50 Z9 57 U1 1 U2 15 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 0146-9592 J9 OPT LETT JI Opt. Lett. PD FEB 15 PY 2007 VL 32 IS 4 BP 355 EP 357 DI 10.1364/OL.32.000355 PG 3 WC Optics SC Optics GA 134LE UT WOS:000244083700011 PM 17356651 ER PT J AU Pinheiro, ACT Descloitres, J Privette, JL Susskind, J Iredell, L Schmaltz, J AF Pinheiro, A. C. T. Descloitres, J. Privette, J. L. Susskind, J. Iredell, L. Schmaltz, J. TI Near-real time retrievals of land surface temperature within the MODIS Rapid Response System SO REMOTE SENSING OF ENVIRONMENT LA English DT Article DE land surface temperature; MODIS; Rapid Response System; direct broadcast ID RESOLUTION IMAGING SPECTRORADIOMETER; VALIDATION; DATASET; AFRICA AB The MODIS Rapid Response (RR) System was developed to meet the near real time needs of the applications community. Generally, its products are available online within hours of the satellite overpass. We recently adapted the standard MODIS land surface temperature (LST) split-window algorithm for use in the RR System. To minimize latency, we eliminated the algorithm's dependency on upstream MODIS products. For example, although the standard MODIS LST requires prior retrieval of air temperature and water vapor from the MODIS scene, the RR LST employs a climatological database of atmospheric values based on a 25-year record of NOAA TOVS observations. The standard and RR algorithms also differ in upstream processing, surface emissivity determination, and use of a cloud mask (RR product does not contain one). Comparison of the MODIS RR and standard LST products suggests that biases are generally less than 0.1 K, and root-mean-square differences are less than I K despite the presence of some larger outliers. Initial validation with field data suggests the absolute uncertainty of the RR product is below I K. The MODIS RR land surface temperature algorithm is a stand-alone computer code. It has no dependencies on external products or toolkits, and is suitable for Direct Broadcast and other processing systems. (c) 2006 Elsevier Inc. All rights reserved. C1 NASA, Goddard Space Flight Ctr, SSAI, Greenbelt, MD 20771 USA. NOAA, Natl Climate Data Ctr, Asheville, NC USA. NASA, Goddard Space Flight Ctr, SAIC, Greenbelt, MD 20771 USA. RP Pinheiro, ACT (reprint author), NASA, Goddard Space Flight Ctr, SSAI, Greenbelt, MD 20771 USA. EM Ana.Pinheiro@noaa.gov RI Privette, Jeffrey/G-7807-2011 OI Privette, Jeffrey/0000-0001-8267-9894 NR 10 TC 18 Z9 18 U1 3 U2 5 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD FEB 15 PY 2007 VL 106 IS 3 BP 326 EP 336 DI 10.1016/j.rse.2006.09.006 PG 11 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA 138HE UT WOS:000244352900004 ER PT J AU Wang, DY Hopfner, MH Tsidu, GM Stiller, GP von Clarmann, T Fischer, H Blumenstock, T Glatthor, N Grabowski, U Hase, F Kellmann, S Linden, A Milz, M Oelhaf, H Schneider, M Steck, T Wetzel, G Lopez-Puertas, M Funke, B Koukouli, ME Nakajima, H Sugita, T Irie, H Urban, J Murtagh, D Santee, ML Toon, G Gunson, MR Irion, FW Boone, CD Walker, K Bernath, PF AF Wang, D. Y. Hoepfner, M. H. Tsidu, G. Mengistu Stiller, G. P. von Clarmann, T. Fischer, H. Blumenstock, T. Glatthor, N. Grabowski, U. Hase, F. Kellmann, S. Linden, A. Milz, M. Oelhaf, H. Schneider, M. Steck, T. Wetzel, G. Lopez-Puertas, M. Funke, B. Koukouli, M. E. Nakajima, H. Sugita, T. Irie, H. Urban, J. Murtagh, D. Santee, M. L. Toon, G. Gunson, M. R. Irion, F. W. Boone, C. D. Walker, K. Bernath, P. F. TI Validation of nitric acid retrieved by the IMK-IAA processor from MIPAS/ENVISAT measurements SO ATMOSPHERIC CHEMISTRY AND PHYSICS LA English DT Article ID LIMB ATMOSPHERIC SPECTROMETER; MOLECULAR SPECTROSCOPIC DATABASE; ATMOS EXPERIMENT; MICHELSON INTERFEROMETER; EMISSION-SPECTRA; HNO3; STRATOSPHERE; MIPAS; SPACE; ALGORITHM AB The Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) onboard the ENVISAT satellite provides profiles of temperature and various trace-gases from limb-viewing mid-infrared emission measurements. The stratospheric nitric acid (HNO3) from September 2002 to March 2004 was retrieved from the MIPAS observations using the science-oriented data processor developed at the Institut fur Meteorologie und Klimaforschung (IMK), which is complemented by the component of non-local thermodynamic equilibrium (non-LTE) treatment from the Instituto de Astrofisica de Andalucia (IAA). The IMK-IAA research product, different from the ESA operational product, is validated in this paper by comparison with a number of reference data sets. Individual HNO3 profiles of the IMK-IAA MIPAS show good agreement with those of the balloon-borne version of MIPAS (MIPAS-B) and the infrared spectrometer MkIV, with small differences of less than 0.5 ppbv throughout the entire altitude range up to about 38 km, and below 0.2 ppbv above 30 km. However, the degree of consistency is largely affected by their temporal and spatial coincidence, and differences of 1 to 2 ppbv may be observed between 22 and 26 km at high latitudes near the vortex boundary, due to large horizontal inhomogeneity of HNO3. Statistical comparisons of MIPAS IMK-IAA HNO3 VMRs with respect to those of satellite measurements of Odin/SMR, ILAS-II, ACE-FTS, as well as the MIPAS ESA product show good consistency. The mean differences are generally +/- 0.5 ppbv and standard deviations of the differences are of 0.5 to 1.5 ppbv. The maximum differences are 2.0 ppbv around 20 to 25 km. This gives confidence in the general reliability of MIPAS HNO3 VMR data and the other three satellite data sets. C1 Forschungszentrum Karlsruhe, D-76021 Karlsruhe, Germany. Univ Karlsruhe, Inst Meteorol & Klimaforsch, Karlsruhe, Germany. Univ New Brunswick, Dept Phys, Fredericton, NB E3B 5A3, Canada. Univ Addis Ababa, Dept Phys, Addis Ababa, Ethiopia. CSIC, Inst Astrofis Andalucia, Granada, Spain. Aristotle Univ Thessaloniki, Dept Phys, GR-54006 Thessaloniki, Greece. Natl Inst Environm Studies, Tsukuba, Ibaraki, Japan. Japan Agcy Marine Earth Sci & Technol, Frontier Res Ctr Global Change, Kanagawa, Japan. Chalmers, Dept Radiol & Space Sci, S-41296 Gothenburg, Sweden. CALTECH, Jet Prop Lab, Pasadena, CA USA. Univ Waterloo, Dept Chem, Waterloo, ON N2L 3G1, Canada. RP Wang, DY (reprint author), Forschungszentrum Karlsruhe, D-76021 Karlsruhe, Germany. EM dwang@unb.ca RI Milz, Mathias/C-9899-2011; The Odin satellite, aeronomy mission/F-1671-2011; Bernath, Peter/B-6567-2012; Blumenstock, Thomas/K-2263-2012; Wetzel, Gerald/A-7065-2013; Hopfner, Michael/A-7255-2013; Stiller, Gabriele/A-7340-2013; Hase, Frank/A-7497-2013; Oelhaf, Hermann/A-7895-2013; von Clarmann, Thomas/A-7287-2013; Glatthor, Norbert/B-2141-2013; Schneider, Matthias/B-1441-2013; Urban, Jo/F-9172-2010; Lopez Puertas, Manuel/M-8219-2013; Funke, Bernd/C-2162-2008; Murtagh, Donal/F-8694-2011; OI Bernath, Peter/0000-0002-1255-396X; Hopfner, Michael/0000-0002-4174-9531; Stiller, Gabriele/0000-0003-2883-6873; von Clarmann, Thomas/0000-0003-2219-3379; Urban, Jo/0000-0001-7026-793X; Lopez Puertas, Manuel/0000-0003-2941-7734; Funke, Bernd/0000-0003-0462-4702; Murtagh, Donal/0000-0003-1539-3559; Koukouli, Maria Elissavet/0000-0002-7509-4027; Milz, Mathias/0000-0002-4478-2185 NR 43 TC 19 Z9 19 U1 0 U2 2 PU COPERNICUS GESELLSCHAFT MBH PI GOTTINGEN PA BAHNHOFSALLEE 1E, GOTTINGEN, 37081, GERMANY SN 1680-7316 EI 1680-7324 J9 ATMOS CHEM PHYS JI Atmos. Chem. Phys. PD FEB 14 PY 2007 VL 7 BP 721 EP 738 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 136LJ UT WOS:000244224100002 ER PT J AU Eyring, V Stevenson, DS Lauer, A Dentener, FJ Butler, T Collins, WJ Ellingsen, K Gauss, M Hauglustaine, DA Isaksen, ISA Lawrence, MG Richter, A Rodriguez, JM Sanderson, M Strahan, SE Sudo, K Szopa, S van Noije, TPC Wild, O AF Eyring, V. Stevenson, D. S. Lauer, A. Dentener, F. J. Butler, T. Collins, W. J. Ellingsen, K. Gauss, M. Hauglustaine, D. A. Isaksen, I. S. A. Lawrence, M. G. Richter, A. Rodriguez, J. M. Sanderson, M. Strahan, S. E. Sudo, K. Szopa, S. van Noije, T. P. C. Wild, O. TI Multi-model simulations of the impact of international shipping on Atmospheric Chemistry and Climate in 2000 and 2030 SO ATMOSPHERIC CHEMISTRY AND PHYSICS LA English DT Article ID MARINE BOUNDARY-LAYER; STRATOSPHERE-TROPOSPHERE EXCHANGE; GLOBAL 3-DIMENSIONAL MODEL; NONMETHANE HYDROCARBONS; OZONE SIMULATIONS; EMISSION CONTROLS; TRANSPORT MODELS; CHEMICAL-MODEL; SHIPS; AIRCRAFT AB The global impact of shipping on atmospheric chemistry and radiative forcing, as well as the associated uncertainties, have been quantified using an ensemble of ten state-of-the-art atmospheric chemistry models and a predefined set of emission data. The analysis is performed for present-day conditions ( year 2000) and for two future ship emission scenarios. In one scenario ship emissions stabilize at 2000 levels; in the other ship emissions increase with a constant annual growth rate of 2.2% up to 2030 ( termed the "Constant Growth Scenario" (CGS)). Most other anthropogenic emissions follow the IPCC ( Intergovernmental Panel on Climate Change) SRES ( Special Report on Emission Scenarios) A2 scenario, while biomass burning and natural emissions remain at year 2000 levels. An intercomparison of the model results with observations over the Northern Hemisphere (25 degrees - 60 degrees N) oceanic regions in the lower troposphere showed that the models are capable to reproduce ozone (O-3) and nitrogen oxides (NOx= NO+ NO2) reasonably well, whereas sulphur dioxide (SO2) in the marine boundary layer is significantly underestimated. The most pronounced changes in annual mean tropospheric NO2 and sulphate columns are simulated over the Baltic and North Seas. Other significant changes occur over the North Atlantic, the Gulf of Mexico and along the main shipping lane from Europe to Asia, across the Red and Arabian Seas. Maximum contributions from shipping to annual mean near-surface O-3 are found over the North Atlantic ( 5 - 6 ppbv in 2000; up to 8 ppbv in 2030). Ship contributions to tropospheric O3 columns over the North Atlantic and Indian Oceans reach 1 DU in 2000 and up to 1.8 DU in 2030. Tropospheric O-3 forcings due to shipping are 9.8 +/- 2.0 mW/m(2) in 2000 and 13.6 +/- 2.3 mW/m(2) in 2030. Whilst increasing O-3, ship NOx simultaneously enhances hydroxyl radicals over the remote ocean, reducing the global methane lifetime by 0.13 yr in 2000, and by up to 0.17 yr in 2030, introducing a negative radiative forcing. The models show future increases in NOx and O-3 burden which scale almost linearly with increases in NOx emission totals. Increasing emissions from shipping would significantly counteract the benefits derived from reducing SO2 emissions from all other anthropogenic sources under the A2 scenario over the continents, for example in Europe. Globally, shipping contributes 3% to increases in O-3 burden between 2000 and 2030, and 4.5% to increases in sulphate under A2/CGS. However, if future ground based emissions follow a more stringent scenario, the relative importance of ship emissions will increase. Inter-model differences in the simulated O-3 contributions from ships are significantly smaller than estimated uncertainties stemming from the ship emission inventory, mainly the ship emission totals, the distribution of the emissions over the globe, and the neglect of ship plume dispersion. C1 DLR, Inst Phys Atmosphare, Oberpfaffenhofen, Germany. Univ Edinburgh, Sch Geosci, Edinburgh, Midlothian, Scotland. European Commiss, Joint Res Ctr, Inst Environm & Sustainabil, Ispra, Italy. Max Planck Inst Chem, D-55128 Mainz, Germany. Met Off, Exeter, Devon, England. Univ Oslo, Dept Geosci, Oslo, Norway. Lab Sci Climat Environm, Gif Sur Yvette, France. Univ Bremen, Inst Environm Phys, Bremen, Germany. Goddard Earth Sci & Technol Ctr, Washington, DC USA. JAMSTEC, Frontier Res Ctr Global Change, Yokohama, Kanagawa, Japan. Royal Netherlands Meteorol Inst, Atmospher Composit Res, NL-3730 AE De Bilt, Netherlands. RP Eyring, V (reprint author), DLR, Inst Phys Atmosphare, Oberpfaffenhofen, Germany. EM Veronika.Eyring@dlr.de RI Wild, Oliver/A-4909-2009; Collins, William/A-5895-2010; Szopa, Sophie/F-8984-2010; Stevenson, David/C-8089-2012; Strahan, Susan/H-1965-2012; Rodriguez, Jose/G-3751-2013; Eyring, Veronika/O-9999-2016; Richter, Andreas/C-4971-2008; Butler, Tim/G-1139-2011 OI Wild, Oliver/0000-0002-6227-7035; Collins, William/0000-0002-7419-0850; Szopa, Sophie/0000-0002-8641-1737; Stevenson, David/0000-0002-4745-5673; Rodriguez, Jose/0000-0002-1902-4649; Eyring, Veronika/0000-0002-6887-4885; Richter, Andreas/0000-0003-3339-212X; NR 71 TC 72 Z9 73 U1 0 U2 23 PU COPERNICUS GESELLSCHAFT MBH PI GOTTINGEN PA BAHNHOFSALLEE 1E, GOTTINGEN, 37081, GERMANY SN 1680-7316 EI 1680-7324 J9 ATMOS CHEM PHYS JI Atmos. Chem. Phys. PD FEB 14 PY 2007 VL 7 BP 757 EP 780 PG 24 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 136LJ UT WOS:000244224100004 ER PT J AU Li, RX Arvidson, RE Di, KH Golombek, M Guinn, J Johnson, A Maimone, M Matthies, LH Malin, M Parker, T Squyres, SW Watters, WA AF Li, Rongxing Arvidson, Raymond E. Di, Kaichang Golombek, Matt Guinn, Joe Johnson, Andrew Maimone, Mark Matthies, Larry H. Malin, Mike Parker, Tim Squyres, Steven W. Watters, Wesley A. TI Opportunity rover localization and topographic mapping at the landing site of Meridiani Planum, Mars SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article AB This paper presents the results of Mars topographic mapping and lander and rover localization for the Opportunity rover at Meridiani Planum during the Mars Exploration Rover (MER) 2003 mission. By Sol 458, the Opportunity rover traversed a distance of 5.20 km. We localized the lander using two-way Doppler radio positioning and cartographic triangulation of craters visible in both orbital and ground images. Additional high-resolution orbital images were taken to verify the determined lander position. Visual odometry and bundle adjustment techniques were applied to overcome wheel slippages, azimuthal angle drift, and other navigation errors (as large as 21% within Eagle crater). In addition, orbit-to-ground image-based adjustment was applied to correct rover location errors where bundle adjustment was not applicable. We generated timely topographic products, including orthoimages, digital terrain models (DTMs), three-dimensional (3-D) crater models, and rover traverse maps. In particular, detailed 3-D terrain models of major features, such as Endurance crater, have been generated using multisite panoramic stereo images based on bundle adjustment and wide baseline stereo technique. C1 Ohio State Univ, Dept Civil & Environm Engn & Geodet Sci, Columbus, OH 43210 USA. Washington Univ, Dept Earth & Planetary Sci, St Louis, MO 63130 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. Malin Space Sci Syst, San Diego, CA 92191 USA. Cornell Univ, Dept Astron, Ithaca, NY 14853 USA. MIT, Dept Earth Atmospher & Planetary Sci, Cambridge, MA 02139 USA. RP Li, RX (reprint author), Ohio State Univ, Dept Civil & Environm Engn & Geodet Sci, Columbus, OH 43210 USA. EM li.282@osu.edu NR 19 TC 8 Z9 8 U1 1 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD FEB 14 PY 2007 VL 112 IS E2 AR E02S90 DI 10.1029/2006JE002776 PG 12 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 138OF UT WOS:000244371300004 ER PT J AU Nielsen, E Wang, XD Gurnett, DA Kirchner, DL Huff, R Orosei, R Safaeinili, A Plaut, JJ Picardi, G AF Nielsen, E. Wang, X. -D. Gurnett, D. A. Kirchner, D. L. Huff, R. Orosei, R. Safaeinili, A. Plaut, J. J. Picardi, G. TI Vertical sheets of dense plasma in the topside Martian ionosphere SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID MARS GLOBAL SURVEYOR; MAGNETIC-FIELD; ANOMALIES; PRECIPITATION AB The low-frequency radar, Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS), on board the Mars Express spacecraft is used to sound electron densities in the topside Martian ionosphere. The radar records the delay times to echoes of reflected radio waves as a function of frequency, yielding spectrograms with traces of radar echoes. At times, two traces are present in spectrograms of the Martian ionosphere. One of these traces corresponds to reflections from the direction to nadir. The other trace originates in a localized reflector in the ionosphere. The local reflectors can be associated with the cusplike regions of near-vertical crustal magnetic fields. The apparent nadir angle of reflection can occasionally increase to 90 degrees. This suggests that steep gradients of the altitude of the electron isodensity exist in the Martian ionosphere and indicates rapid horizontal spatial variations of vertical diffusion of Martian plasma. Such gradients may arise owing to preferential access of solar wind to the cusplike regions or to precipitation of energetic electrons from acceleration regions located on cusp magnetic field lines high above the ionosphere. C1 Max Planck Inst Solar Syst Res, D-37191 Katlenburg Lindau, Germany. Univ Iowa, Dept Phys & Astron, Iowa City, IA 52242 USA. Ist Astrofis Spaziale & Fis Cosm Rona, I-00133 Rome, Italy. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Roma La Sapienza, Infocom Dept, I-00184 Rome, Italy. RP Nielsen, E (reprint author), Max Planck Inst Solar Syst Res, D-37191 Katlenburg Lindau, Germany. EM nielsen@mps.mpg.de OI Wang, Xiao-Dong/0000-0003-0574-4423 NR 18 TC 19 Z9 20 U1 1 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD FEB 14 PY 2007 VL 112 IS E2 AR E02003 DI 10.1029/2006JE002723 PG 10 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 138OF UT WOS:000244371300002 ER PT J AU Cable, ML Kirby, JP Sorasaenee, K Gray, HB Ponce, A AF Cable, Morgan L. Kirby, James P. Sorasaenee, Karn Gray, Harry B. Ponce, Adrian TI Bacterial spore detection by [Tb3+(macrocycle)(dipicolinate)] luminescence SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID TERBIUM DIPICOLINATE PHOTOLUMINESCENCE; LANTHANIDE(III) COMPLEXES; ENDOSPORE DETECTION; RAMAN-SPECTROSCOPY; GERMINATION; EUROPIUM; ANTHRAX; WATER; ACID; PYRIDINE-2,6-DICARBOXYLATE AB Dipicolinic acid (DPA) is a unique constituent of bacterial spores, a dormant form of Bacillus and Clostridium, which can be detected using DPA-triggered Tb3+ luminescence. [Tb(DO2A)](+) improves the sensitivity of bacterial spore detection over Tb3+(aq) owing to the exclusion of coordinated water molecules and represents the first step toward construction of a DPA receptor site with enhanced binding selectivity. The title ternary [Tb(DO2A)(DPA)](-) complex was structurally characterized and features two DO2A-DPA interligand hydrogen interactions that stabilize the complex. C1 CALTECH, Beckman Inst, Pasadena, CA 91125 USA. Jet Prop Lab, In Situ Instruments Sect, Pasadena, CA 91109 USA. RP Kirby, JP (reprint author), CALTECH, Beckman Inst, Pasadena, CA 91125 USA. EM james.p.kirby@jpl.nasa.gov; hbgray@caltech.edu; ponce@caltech.edu NR 34 TC 96 Z9 98 U1 4 U2 45 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0002-7863 J9 J AM CHEM SOC JI J. Am. Chem. Soc. PD FEB 14 PY 2007 VL 129 IS 6 BP 1474 EP 1475 DI 10.1021/ja061831t PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA 133GF UT WOS:000244000700001 PM 17243674 ER PT J AU Garces, JE Bozzolo, G Hofman, G Rest, J AF Garces, Jorge E. Bozzolo, Guillermo Hofman, Gerard Rest, Jeffrey TI Role of Si on the Al behavior in the reaction layer of Al/UMo diffusion couples SO APPLIED PHYSICS LETTERS LA English DT Article ID IRRADIATION BEHAVIOR; DISPERSION FUEL; LOW-TEMPERATURE; ALLOY; ALUMINUM AB The basic experimental features characterizing the Al-Si/U-Mo interface are identified in this atomistic modeling effort, such as the formation of interfacial compounds, Si depletion in the Al matrix near the interface, reduced Al diffusion in the UMo solid solution, and the interaction between Mo and Si which inhibits Al and Si diffusion to the UMo bulk. (c) 2007 American Institute of Physics. C1 Comis Nacl Energia Atom, Ctr Atom Bariloche, RA-8400 San Carlos De Bariloche, Rio Negro, Argentina. NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. Ohio Aerosp Inst, Cleveland, OH 44142 USA. Argonne Natl Lab, Argonne, IL 60439 USA. RP Garces, JE (reprint author), Comis Nacl Energia Atom, Ctr Atom Bariloche, RA-8400 San Carlos De Bariloche, Rio Negro, Argentina. EM guillermobozzolo@oai.org NR 15 TC 3 Z9 3 U1 1 U2 2 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD FEB 12 PY 2007 VL 90 IS 7 AR 074104 DI 10.1063/1.2535592 PG 3 WC Physics, Applied SC Physics GA 136UO UT WOS:000244249800092 ER PT J AU Nemeth, NN Evans, LJ Jadaan, OM Sharpe, WN Beheim, GM Trapp, MA AF Nemeth, N. N. Evans, L. J. Jadaan, O. M. Sharpe, W. N. Beheim, G. M. Trapp, M. A. TI Fabrication and probabilistic fracture strength prediction of high-aspect-ratio single crystal silicon carbide microspecimens with stress concentration SO THIN SOLID FILMS LA English DT Article; Proceedings Paper CT Symposium on Mechanical Behavior of Thin Films and Small Structures held at the 2005TMS Annual Meeting CY FEB 13-17, 2005 CL San Francisco, CA SP TMS DE silicon carbide; strength; Weibull; MEMS ID MECHANICAL STRENGTH; POLYSILICON FILMS AB Single crystal silicon carbide micro-sized tensile specimens were fabricated with deep reactive ion etching (DRIE) in order to investigate the effect of stress concentration on the roorn-temperature fracture strength. The fracture strength was defined as the level of stress at the highest stressed location in the structure at the instant of specimen rupture. Specimens with an elliptical hole, a circular hole, and without a hole (and hence with no stress concentration) were made. The average fracture strength of specimens with a higher stress concentration was larger than the average fracture strength of specimens with a lower stress concentration. Average strength of elliptical-hole, circular-hole, and without-hole specimens was 1.53, 1.26, and 0.66 GPa, respectively. Significant scatter in strength was observed with the Weibull modulus ranging between 2 and 6. No fractographic examination was performed but it was assumed that the strength controlling flaws originated from etching grooves along the specimen side-walls. The increase of observed fracture strength with increasing stress concentration was compared to predictions made with the Weibull stress-integral formulation by using the NASA CARES/Life code. In the analysis isotropic material and fracture behavior was assumed - hence it was not a completely rigorous analysis. However, even with these assumptions good correlation was achieved for the circular-hole specimen data when using the specimen data Without stress concentration as a baseline. Strength was over predicted for the elliptical-hole specimen data. Significant specimen-to-specimen dimensional variation existed in the elliptical-hole specimens due to variations in the nickel mask used in the etching. To simulate the additional effect of the dimensional variability on the probabilistic strength response for the single crystal specimens the ANSYS Probabilistic Design System (PDS) was used with CARES/Life. The ANSYS-PDS & CARES/Life simulation correlated better to the elliptical-hole specimen data than CARES/Life predictions based on average specimen dimensions. (c) 2006 Elsevier B.V. All rights reserved. C1 NASA, Glenn Res Ctr, Mech & Lifing, Cleveland, OH 44135 USA. NASA, Glenn Res Ctr, Sensors & Elect Branch, Cleveland, OH 44135 USA. Univ Wisconsin, Coll Engn Math & Sci, Platteville, WI 53818 USA. Johns Hopkins Univ, Dept Mech Engn, Baltimore, MD 21218 USA. Carnegie Mellon Univ, Dept Mech Engn, Pittsburgh, PA 15213 USA. RP Nemeth, NN (reprint author), NASA, Glenn Res Ctr, Mech & Lifing, 21000 Brookpk Rd,Mail Stop 47-7, Cleveland, OH 44135 USA. EM Noel.N.Nemeth@grc.nasa.gov NR 18 TC 17 Z9 17 U1 1 U2 6 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0040-6090 J9 THIN SOLID FILMS JI Thin Solid Films PD FEB 12 PY 2007 VL 515 IS 6 BP 3283 EP 3290 DI 10.1016/j.tsf.2006.01.041 PG 8 WC Materials Science, Multidisciplinary; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Materials Science; Physics GA 140HZ UT WOS:000244496800019 ER PT J AU Eplee, RE Patt, FS Barnes, RA McClain, CR AF Eplee, Robert E., Jr. Patt, Frederick S. Barnes, Robert A. McClain, Charles R. TI SeaWiFS long-term solar diffuser reflectance and sensor noise analyses SO APPLIED OPTICS LA English DT Article ID ORBIT AB The NASA Ocean Biology Processing Group's Calibration and Validation (Cal/Val) team has undertaken an analysis of the mission-long Sea-Viewing Wide Field-of-View Sensor (SeaWiFS) solar calibration time series to assess the long-term degradation of the solar diffuser reflectance over 9 years on orbit. The SeaWiFS diffuser is an aluminum plate coated with YB71 paint. The bidirectional reflectance distribution function of the diffuser was not fully characterized before launch, so the Cal/Val team has implemented a regression of the solar incidence angles and the drift in the node of the satellite's orbit against the diffuser time series to correct for solar incidence angle effects. An exponential function with a time constant of 200 days yields the best fit to the diffuser time series. The decrease in diffuser reflectance over the mission is wavelength dependent, ranging from 9% in the blue (412 nm) to 5% in the red and near infrared (670-865 nm). The Cal/Val team has developed a methodology for computing the signal-to-noise ratio (SNR) for SeaWiFS on orbit from the diffuser time series corrected for both the varying solar incidence angles and the diffuser reflectance degradation. A sensor noise model is used to compare on-orbit SNRs computed for radiances reflected from the diffuser with prelaunch SNRs measured at typical radiances specified for the instrument. To within the uncertainties in the measurements, the SNRs for SeaWiFS have not changed over the mission. The on-orbit performance of the SeaWiFS solar diffuser should offer insight into the long-term on-orbit performance of solar diffusers on other instruments, such as the Moderate-Resolution Imaging Spectrometer [currently flying on the Earth Observing System (EOS) Terra and Aqua satellites], the Visible and Infrared Radiometer Suite [scheduled to fly on the NASA National Polar-orbiting Operational Environmental Satellite System (NPOESS) and NPOESS Preparatory Project (NPP) satellites] and the Advanced Baseline Imager [scheduled to fly on the National Oceanic and Atmospheric Administration Geostationary Environmental Operational Satellite Series R (GOES-R) satellites]. (c) 2007 Optical Society of America. C1 Sci Applicat Int Corp, Beltsville, MD 20705 USA. NASA, Goddard Space Flight Ctr, Ocean Biol Proc Grp, Greenbelt, MD 20771 USA. RP Eplee, RE (reprint author), Sci Applicat Int Corp, 4600 Powder Mill Rd,Suite 400, Beltsville, MD 20705 USA. EM eplee@seawifs.gsfc.nasa.gov NR 15 TC 12 Z9 12 U1 3 U2 5 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1559-128X EI 2155-3165 J9 APPL OPTICS JI Appl. Optics PD FEB 10 PY 2007 VL 46 IS 5 BP 762 EP 773 DI 10.1364/AO.46.000762 PG 12 WC Optics SC Optics GA 134JX UT WOS:000244080400017 PM 17279164 ER PT J AU Johnston, DE Sheldon, ES Tasitsiomi, A Frieman, JA Wechsler, RH Mckay, TA AF Johnston, David E. Sheldon, Erin S. Tasitsiomi, Argyro Frieman, Joshua A. Wechsler, Risa H. McKay, Timothy A. TI Cross-correlation lensing: Determining galaxy and cluster mass profiles from statistical weak-lensing measurements SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : clusters : general; gravitational lensing; large-scale structure of universe ID DIGITAL SKY SURVEY; LARGE-SCALE STRUCTURE; HUBBLE DEEP FIELD; COLD DARK MATTER; COSMOLOGICAL PARAMETERS; DISSIPATIONLESS SIMULATIONS; POWER SPECTRUM; HALO MASSES; UNIVERSE; RECONSTRUCTION AB We present a new nonparametric method for determining mean 3D density and mass profiles from weak-lensing measurements around stacked samples of galaxies or clusters, that is, from measurement of the galaxy-shear or cluster-shear correlation functions. Since the correlation function is statistically isotropic, this method evades problems, such as projection of large-scale structure along the line of sight or halo asphericity, that complicate attempts to infer masses from weak-lensing measurements of individual objects. We demonstrate the utility of this method in measuring halo profiles, galaxy-mass and cluster-mass cross-correlation functions, and cluster virial masses. We test this method on an N-body simulation and show that it correctly and accurately recovers the 3D density and mass profiles of halos. We find no evidence of problems due to amass sheet degeneracy in the simulation. Cross-correlation lensing provides a powerful method for calibrating the mass-observable relation for use in measurement of the cluster mass function in large surveys. It can also be used on large scales to measure and remove the halo bias and thereby provide a direct measurement of Omega(m)sigma(8). C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. NYU, Dept Phys, New York, NY 10003 USA. Princeton Univ Observ, Princeton, NJ 08544 USA. Univ Chicago, Kavli Inst Cosmol Phys, Chicago, IL 60637 USA. Univ Chicago, Dept Astron & Astrophys, Chicago, IL 60637 USA. Fermilab Natl Accelerator Lab, Batavia, IL 60510 USA. Univ Michigan, Dept Phys, Ann Arbor, MI 48109 USA. RP Johnston, DE (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM davej@astro.caltech.edu RI McKay, Timothy/C-1501-2009; OI McKay, Timothy/0000-0001-9036-6150; Wechsler, Risa/0000-0003-2229-011X NR 92 TC 48 Z9 48 U1 0 U2 3 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X EI 1538-4357 J9 ASTROPHYS J JI Astrophys. J. PD FEB 10 PY 2007 VL 656 IS 1 BP 27 EP 41 DI 10.1086/510060 PN 1 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 133SD UT WOS:000244032600002 ER PT J AU Markowitz, A Papadakis, I Arevalo, P Turner, TJ Miller, L Reeves, JN AF Markowitz, A. Papadakis, I. Arevalo, P. Turner, T. J. Miller, L. Reeves, J. N. TI The energy-dependent X-ray timing characteristics of the narrow-line Seyfert 1 Mrk 766 SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : active; galaxies : individual (Mrk 766); galaxies : Seyfert; X-rays : galaxies ID ACTIVE GALACTIC NUCLEI; QUASI-PERIODIC OSCILLATIONS; BLACK-HOLE CANDIDATES; CYGNUS X-1; HIGH-FREQUENCY; XMM-NEWTON; GX 339-4; VELOCITY DISPERSION; ACCRETION DISCS; POWER SPECTRUM AB We present the energy-dependent power spectral density (PSD) and cross spectral properties of Mrk 766, obtained from combining data obtained during an XMM-Newton observation spanning six revolutions in 2005 with data obtained from an XMM-Newton long look in 2001. The PSD shapes and rms-flux relations are found to be consistent between the 2001 and 2005 observations, suggesting that the 2005 observation is simply a low-flux extension of the 2001 observation and permitting us to combine the two data sets. The resulting PSD has the highest temporal frequency resolution for any AGN PSD measured to date. Applying a broken power-law model yields break frequencies that increase in temporal frequency with photon energy. Obtaining a good fit when assuming energy-independent break frequencies requires the presence of a Lorentzian at (4.6 +/- 0.4) x 10(-4) Hz whose strength increases with photon energy, a behavior seen in black hole X-ray binaries. The cross spectral properties are measured; temporal frequency-dependent soft-to-hard time lags are detected in this object for the first time. Cross spectral results are consistent with those for other accreting black hole systems. The results are discussed in the context of several variability models, including those based on inwardly propagating viscosity variations in the accretion disk. C1 NASA, Goddard Space Flight Ctr, Xray Astrophys Lab, Greenbelt, MD 20771 USA. Univ Crete, Dept Phys, Iraklion, Greece. Univ Southampton, Sch Phys & Astron, Southampton, Hants, England. Univ Maryland, Dept Phys, Baltimore, MD USA. Univ Oxford, Dept Phys, Oxford, England. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. RP Markowitz, A (reprint author), NASA, Goddard Space Flight Ctr, Xray Astrophys Lab, Greenbelt, MD 20771 USA. EM agm@milkyway.gsfc.nasa.gov RI Papadakis, Iossif/C-3235-2011 NR 64 TC 26 Z9 26 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD FEB 10 PY 2007 VL 656 IS 1 BP 116 EP 128 DI 10.1086/510616 PN 1 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 133SD UT WOS:000244032600009 ER PT J AU Pandian, JD Goldsmith, PF Deshpande, AA AF Pandian, Jagadheep D. Goldsmith, Paul F. Deshpande, Avinash A. TI The Arecibo methanol maser Galactic plane survey. I. Data SO ASTROPHYSICAL JOURNAL LA English DT Article DE masers; radio lines : ISM; stars : formation; surveys ID 6.7 GHZ; IRAS SOURCES; STAR-FORMATION; REGIONS; EMISSION AB We present the results of an unbiased survey for 6.7 GHz methanol masers in the Galactic plane carried out using the 305 m Arecibo radio telescope. A total of 18.2 deg(2) was surveyed with uniform sampling at 35.2 <= l <= 53.7 degrees, \b\ <= 0.41 degrees. The large collecting area of Arecibo and the sensitive C-Band High receiver allowed the survey to be complete at the level of 0.27 Jy, making this the most sensitive blind survey carried out to date. We detected a total of 86 sources, 48 of which are new detections. Most of the new detections have a peak flux density below 2 Jy. Many methanol masers are clustered, reflecting the formation of massive stars in clusters. C1 Cornell Univ, Dept Astron, Ithaca, NY 14853 USA. CALTECH, Jet Prop Lab, Pasadena, CA USA. Raman Res Inst, Bangalore 560080, Karnataka, India. NAIC, Arecibo, PR USA. RP Pandian, JD (reprint author), Cornell Univ, Dept Astron, Ithaca, NY 14853 USA. EM jagadheep@astro.cornell.edu; Paul.F.Goldsmith@jpl.nasa.gov; desh@rri.res.in RI Deshpande, Avinash/D-4868-2012; Astronomy & Astrophysics Group, Raman Res Institute/D-4046-2012; M, Manjunath/N-4000-2014; Goldsmith, Paul/H-3159-2016 OI M, Manjunath/0000-0001-8710-0730; NR 25 TC 49 Z9 49 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD FEB 10 PY 2007 VL 656 IS 1 BP 255 EP 274 DI 10.1086/510512 PN 1 PG 20 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 133SD UT WOS:000244032600022 ER PT J AU Quanz, SP Apai, D Henning, T AF Quanz, S. P. Apai, D. Henning, Th. TI Dust rings and filaments around the isolated young star V1331 Cygni SO ASTROPHYSICAL JOURNAL LA English DT Article DE ISM : individual (LDN 981); stars : formation; stars : individual (V1331 Cyg) ID FU ORIONIS STARS; T-TAURI STARS; MASS-LOSS; OBJECTS; FRAGMENTATION; EVOLUTION; CORES AB We characterize the small- and large-scale environment of the young star V1331 Cygni with high-resolution HST WFPC2 and Digitized Sky Survey images. In addition to a previously known outer dust ring ( approximate to 30 '' in diameter), the WFPC2 scattered light image reveals an inner dust ring for the first time. This ring has a maximum radius of approximate to 6.5 '' and is possibly related to a molecular envelope. Large-scale optical images show that V1331 Cyg is located at the tip of a long dust filament linking it to the dark cloud LDN 981. We discuss the origin of the observed dust morphology and analyze the object's relation to its parent dark cloud LDN 981. Finally, based on recent results from the literature, we investigate the properties of V1331 Cyg and conclude that in its current state the object does not show sufficient evidence to be characterized as an FU Ori object. C1 Max Planck Inst Astron, D-69117 Heidelberg, Germany. Univ Arizona, Steward Observ, Tucson, AZ USA. NASA, Ames Res Ctr, Astrobiol Inst, Moffett Field, CA 94035 USA. RP Quanz, SP (reprint author), Max Planck Inst Astron, Konigstuhl 17, D-69117 Heidelberg, Germany. EM quanz@mpia.de NR 35 TC 12 Z9 12 U1 0 U2 2 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD FEB 10 PY 2007 VL 656 IS 1 BP 287 EP 292 DI 10.1086/510376 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 133SD UT WOS:000244032600024 ER PT J AU Bhattacharyya, S Strohmayer, TE AF Bhattacharyya, Sudip Strohmayer, Tod E. TI An unusual precursor burst with oscillations from SAX J1808.4-3658 SO ASTROPHYSICAL JOURNAL LA English DT Article DE methods : data analysis; stars : neutron; techniques : miscellaneous; X-rays : binaries; X-rays : bursts; X-rays : individual (SAX J1808.4-3658) ID X-RAY-BURSTS; ROTATING NEUTRON-STARS; MILLISECOND PULSAR; LIGHT CURVES; BRIGHTNESS OSCILLATIONS; THERMONUCLEAR FLAMES; FREQUENCY EVOLUTION; HARMONIC CONTENT; RISING PHASE; 4U 1636-53 AB We report the finding of an unusual, weak precursor to a thermonuclear X-ray burst from the accreting millisecond pulsar SAX J1808.4 - 3658. The burst in question was observed on 2002 October 19 with the Rossi X-Ray Timing Explorer Proportional Counter Array (RXTE PCA). The precursor began approximate to 1 s prior to the onset of a strong radius expansion burst, lasted for about 0.4 s, and exhibited strong oscillations at the 401 Hz spin frequency. Oscillations are not detected in the approximate to 0.5 s interval between the precursor and the main burst. The estimated peak photon flux and energy fluence of the precursor are about 1/25 and 1/500 that of the main burst, respectively. From joint spectral and temporal modeling, we find that an expanding burning region with a relatively low temperature on the spinning neutron star surface can explain the oscillations, as well as the faintness of the precursor with respect to the main part of the burst. We discuss some of the implications of our findings for the ignition and spreading of thermonuclear flames on neutron stars. C1 NASA, Goddard Space Flight Ctr, Xray Astrophys Lab, Explorat Universe Div, Greenbelt, MD 20771 USA. Univ Maryland, Dept Astron, College Pk, MD 20742 USA. RP Bhattacharyya, S (reprint author), NASA, Goddard Space Flight Ctr, Xray Astrophys Lab, Explorat Universe Div, Greenbelt, MD 20771 USA. EM sudip@milkyway.gsfc.nasa.gov; stroh@clarence.gsfc.nasa.gov NR 48 TC 4 Z9 4 U1 0 U2 3 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD FEB 10 PY 2007 VL 656 IS 1 BP 414 EP 419 DI 10.1086/510359 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 133SD UT WOS:000244032600036 ER PT J AU Homan, J van der Klis, M Wijnands, R Belloni, T Fender, R Klein-Wolt, M Casella, P Mendez, M Gallo, E Lewin, WHG Gehrels, N AF Homan, Jeroen van der Klis, Michiel Wijnands, Rudy Belloni, Tomaso Fender, Rob Klein-Wolt, Marc Casella, Piergiorgio Mendez, Mariano Gallo, Elena Lewin, Walter H. G. Gehrels, Neil TI Rossi X-ray Timing Explorer observations of the first transient Z source XTE J1701-462: Shedding new light on mass accretion in luminous neutron star X-ray binaries SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; stars : individual (XTE J1701-462); stars : neutron; X-rays : stars ID QUASI-PERIODIC OSCILLATIONS; SOURCE CYGNUS X-2; SOURCE GX 340+0; SCORPIUS X-1; SPECTRAL BEHAVIOR; Z-TRACK; FLARING-BRANCH; CIRCINUS X-1; 4U 1608-52; DISCOVERY AB We report on the first 10 weeks of RXTE observations of the X-ray transient XTE J1701 - 462 and conclude that it had all the characteristics of the neutron star Z sources, i.e., the brightest persistent neutron star low-mass X-ray binaries. These include the typical Z-shaped tracks traced out in X-ray color diagrams and the variability components detected in the power spectra, such as kHz QPOs and normal and horizontal branch oscillations. XTE J1701 - 462 is the first transient Z source and provides unique insights into mass accretion rate ((m) over dot) and luminosity dependencies in neutron star X-ray binaries. As its overall luminosity decreased, we observed a switch between two types of Z source behavior, with the branches of the Z track changing their shape and/or orientation. We interpret this as an extreme case of the more moderate long-term changes seen in the persistent Z sources and suggest that they result from changes in. m. We also suggest that the Cyg-like Z sources (Cyg X- 2, GX 5 - 1, and GX 340+0) are substantially more luminous (> 50%) than the Sco-like Z sources (Sco X- 1, GX 17+2, and GX 349+2). Adopting a possible explanation for the behavior of kHz QPOs, which involves a prompt as well as a filtered response to changes in. m, we further propose that changes in. m can explain both movement along the Z track and changes in the shape of the Z track. We discuss some consequences of this and consider the possibility that the branches of the Z will smoothly evolve into the branches observed in X-ray color diagrams of the less luminous atoll sources, although not in a way that was previously suggested. C1 MIT, Kavli Inst Astrophys & Space Res, Cambridge, MA 02139 USA. Univ Amsterdam, Astron Inst Anton Pannekoek, Amsterdam, Netherlands. Osserv Astron Brera, INAF, Merate, LC, Italy. Univ Southampton, Sch Phys & Astron, Southampton, Hants, England. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. SRON, Netherlands Inst Space Res, Utrecht, Netherlands. Univ Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USA. RP Homan, J (reprint author), MIT, Kavli Inst Astrophys & Space Res, 77 Massachusetts Ave, Cambridge, MA 02139 USA. EM jeroen@space.mit.edu RI Gehrels, Neil/D-2971-2012; Mendez, Mariano/C-8011-2012; OI Mendez, Mariano/0000-0003-2187-2708; Casella, Piergiorgio/0000-0002-0752-3301 NR 66 TC 50 Z9 50 U1 0 U2 2 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD FEB 10 PY 2007 VL 656 IS 1 BP 420 EP 430 DI 10.1086/510447 PN 1 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 133SD UT WOS:000244032600037 ER PT J AU Porras, A Jorgensen, JK Allen, LE Evans, NJ Bourke, TL Alcala, JM Dunham, MM Blake, GA Chapman, N Cieza, L Harvey, PM Huard, TL Koerner, DW Mundy, LG Myers, PC Padgett, DL Sargent, AI Stapelfeldt, KR Teuben, P van Dishoeck, EF Wahhaj, Z Young, KE AF Porras, Alicia Jorgensen, Jes K. Allen, Lori E. Evans, Neal J., II Bourke, Tyler L. Alcala, Juan M. Dunham, Michael M. Blake, Geoffrey A. Chapman, Nicholas Cieza, Lucas Harvey, Paul M. Huard, Tracy L. Koerner, David W. Mundy, Lee G. Myers, Philip C. Padgett, Deborah L. Sargent, Anneila I. Stapelfeldt, Karl R. Teuben, Peter van Dishoeck, Ewine F. Wahhaj, Zahed Young, Kaisa E. TI The SPITZER c2d survey of large, nearby, interstellar clouds. V. Chamaeleon II observed with IRAC SO ASTROPHYSICAL JOURNAL LA English DT Article DE stars : formation; stars : low-mass, brown dwarfs ID YOUNG STELLAR CLUSTER; HERBIG-HARO OBJECTS; ARRAY CAMERA IRAC; DARK-CLOUD; DENSE CORES; SPACE-TELESCOPE; MOLECULAR CLOUDS; STAR-FORMATION; BROWN DWARF; HH 54 AB We present IRAC (3.6, 4.5, 5.8, and 8.0 mu m) observations of the Chamaeleon II molecular cloud. The observed area covers about 1 deg(2) defined by A(V) > 2. Analysis of the data in the 2005 c2d catalogs reveals a small number of sources ( 40) with properties similar to those of young stellar or substellar objects (YSOs). The surface density of these YSO candidates is low, and contamination by background galaxies appears to be substantial, especially for sources classified as Class I or flat spectral energy distribution ( SED). We discuss this problem in some detail and conclude that very few of the candidate YSOs in early evolutionary stages are actually in the Cha II cloud. Using a refined set of criteria, we define a smaller, but more reliable, set of 24 YSO candidates. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. INAOE, Tonantzintla, Pue, Mexico. Univ Texas, Dept Astron, Austin, TX 78712 USA. Osserv Astron Capodimonte, INAF, Naples, Italy. CALTECH, Div Geol & Planetary Sci, Pasadena, CA 91125 USA. Univ Maryland, Dept Astron, College Pk, MD 20742 USA. No Arizona Univ, Dept Phys & Astron, Flagstaff, AZ 86011 USA. CALTECH, Spitzer Sci Ctr, Pasadena, CA USA. CALTECH, Div Phys Math & Astron, Pasadena, CA USA. CALTECH, Jet Prop Lab, Pasadena, CA USA. Leiden Observ, Leiden, Netherlands. Univ Hawaii, Inst Astron, Honolulu, HI 96822 USA. Nicholls State Univ, Dept Phys Sci, Thibodaux, LA 70310 USA. RP Porras, A (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. EM aporras@cfa.harvard.edu; jjorgensen@cfa.harvard.edu; leallen@cfa.harvard.edu; nje@astro.as.utexas.edu; tbourke@cfa.harvard.edu; jmae@sun1.na.astro.it; mdunham@astro.as.utexas.edu; gab@gps.caltech.edu; chapman@astro.umd.edu; lcieza@astro.as.utexas.edu; pmh@astro.as.utexas.edu; thuard@cfa.harvard.edu; david.koerner@nau.edu; lgm@astro.umd.edu; pmyers@cfa.harvard.edu; dlp@ipac.caltech.edu; afs@astro.caltech.edu; krs@exoplanet.jpl.nasa.gov; teuben@astro.umd.edu; ewine@strw.LeidenUniv.nl; Zahed.wahhaj@nau.ed; kaisa.young@gmail.com RI Stapelfeldt, Karl/D-2721-2012; OI Alcala, Juan Manuel/0000-0001-8657-095X NR 47 TC 35 Z9 35 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD FEB 10 PY 2007 VL 656 IS 1 BP 493 EP 504 DI 10.1086/510422 PN 1 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 133SD UT WOS:000244032600045 ER PT J AU Brosius, JW Rabin, DM Thomas, RJ AF Brosius, Jeffrey W. Rabin, Douglas M. Thomas, Roger J. TI Doppler velocities measured in coronal emission lines from a bright point observed with the EUNIS sounding rocket SO ASTROPHYSICAL JOURNAL LA English DT Article DE Sun : corona; Sun : magnetic fields; Sun : transition region; Sun : UV radiation ID LOOP RADIATIVE HYDRODYNAMICS; SOLAR ACTIVE-REGION; EXTREME-ULTRAVIOLET SPECTRUM; CHROMOSPHERIC EVAPORATION; MAGNETIC CANCELLATION; MODEL; RECONNECTION; RESOLUTION; BIPOLES; IMAGER AB Spectroscopic measurements of a coronal bright point obtained with the Extreme Ultraviolet Normal Incidence Spectrograph (EUNIS) sounding rocket instrument on 2006 April 12 show both upflows and downflows in all five of the best observed emission lines. Relative velocities on opposite sides of the feature were found to be +/- 15 km s(-1) in the line of He II 303.8 angstrom (formed at T approximate to 5 x 10(4) K), +/- 14 km s(-1) in Mg IX 368.1 angstrom (T approximate to 9.5 x 10(5) K), +/-26 km s(-1) in Fe XIV 334.2 angstrom (T approximate to 2.0 x 10(6) K), and +/- 35 km s(-1) in both Fe XVI 335.4 and 360.8 angstrom (T approximate to 2.5 x 10(6) K). The latter are the hottest lines for which Doppler velocities have been reported in 6 a bright point. Photospheric longitudinal magnetograms reveal that the photospheric magnetic fields underlying the bright point were canceling during the EUNIS observation. Based on existing bright point models, this suggests that the observed hot flows were associated with magnetic reconnection. C1 Catholic Univ Amer, NASA, Goddard Space Flight Ctr, Solar Phys Lab, Greenbelt, MD 20771 USA. RP Brosius, JW (reprint author), Catholic Univ Amer, NASA, Goddard Space Flight Ctr, Solar Phys Lab, Greenbelt, MD 20771 USA. EM brosius@lssp-mail.gsfc.nasa.gov; Douglas.M.Rabin@nasa.gov; Roger.J.Thomas@nasa.gov NR 35 TC 22 Z9 23 U1 0 U2 4 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD FEB 10 PY 2007 VL 656 IS 1 BP L41 EP L44 DI 10.1086/512185 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 133SG UT WOS:000244032900011 ER PT J AU Wisniewski, JP Kowalski, AF Bjorkman, KS Bjorkman, JE Carciofi, AC AF Wisniewski, J. P. Kowalski, A. F. Bjorkman, K. S. Bjorkman, J. E. Carciofi, A. C. TI Toward mapping the detailed density structure of classical Be circumstellar disks SO ASTROPHYSICAL JOURNAL LA English DT Article DE circumstellar matter; stars : emission-line, Be; stars : individual (48 Librae, zeta Tauri) ID ONE-ARMED OSCILLATIONS; HIGH-RESOLUTION EMISSION; LINE-PROFILES; ZETA-TAURI; REPRESENTATIVE SAMPLE; BAND SPECTROSCOPY; TERM VARIABILITY; STARS; V/R; SPECTRA AB The first results from a near-contemporaneous optical and infrared spectroscopic observing program designed to probe the detailed density structure of classical Be circumstellar disks are presented. We report the discovery of asymmetrical infrared emission lines of He I, O I, Fe II, and the Brackett, Paschen, and Pfund series lines of H I that exhibit an opposite V/R orientation (V>R) to that observed for the optical Balmer H alpha line (V 100 eV) is Saturn's middle or outer magnetosphere, perhaps transported to the inner magnetosphere by radial diffusion regulated by interchange-like injections. Hot electrons undergo heavy losses inside L similar to 6 and the distance to which the hot electron component penetrates into the neutral cloud is energy-dependent, with the coolest fraction of the hot plasma penetrating to the lowest L-shells. This can arise through energy-dependent radial transport during the interchange process and/or loss through the planetary loss cone. C1 Johns Hopkins Univ, Appl Phys Lab, Laurel, MD USA. Rice Univ, Dept Phys & Astron, Houston, TX 77251 USA. European Space Agcy, Res & Sci Support Dept, NL-2200 AG Noordwijk, Netherlands. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Virginia, Charlottesville, VA USA. UCL, Mullard Space Sci Lab, London, England. SW Res Inst, San Antonio, TX USA. Los Alamos Natl Lab, Space & Atmospher Sci Grp, Los Alamos, NM USA. Univ London Imperial Coll Sci Technol & Med, Dept Space & Atmospher Phys, London, England. RP Rymer, AM (reprint author), Johns Hopkins Univ, Appl Phys Lab, Johns Hopkins Rd, Laurel, MD USA. EM abigail.rymer@jhuapl.edu RI Coates, Andrew/C-2396-2008; Paranicas, Christopher/B-1470-2016; Smith, Howard/H-4662-2016; Mauk, Barry/E-8420-2017 OI Coates, Andrew/0000-0002-6185-3125; Paranicas, Christopher/0000-0002-4391-8255; Smith, Howard/0000-0003-3537-3360; Mauk, Barry/0000-0001-9789-3797 FU Science and Technology Facilities Council [PP/D00084X/1] NR 50 TC 56 Z9 56 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD FEB 9 PY 2007 VL 112 IS A2 AR A02201 DI 10.1029/2006JA012017 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 136EM UT WOS:000244205400002 ER PT J AU Bertram, TH Perring, AE Wooldridge, PJ Crounse, JD Kwan, AJ Wennberg, PO Scheuer, E Dibb, J Avery, M Sachse, G Vay, SA Crawford, JH McNaughton, CS Clarke, A Pickering, KE Fuelberg, H Huey, G Blake, DR Singh, HB Hall, SR Shetter, RE Fried, A Heikes, BG Cohen, RC AF Bertram, Timothy H. Perring, Anne E. Wooldridge, Paul J. Crounse, John D. Kwan, Alan J. Wennberg, Paul O. Scheuer, Eric Dibb, Jack Avery, Melody Sachse, Glen Vay, Stephanie A. Crawford, James H. McNaughton, Cameron S. Clarke, Antony Pickering, Kenneth E. Fuelberg, Henry Huey, Greg Blake, Donald R. Singh, Hanwant B. Hall, Samuel R. Shetter, Richard E. Fried, Alan Heikes, Brian G. Cohen, Ronald C. TI Direct measurements of the convective recycling of the upper troposphere SO SCIENCE LA English DT Article ID INDUCED FLUORESCENCE DETECTION; TRACE GAS-TRANSPORT; NITRIC-ACID; MIDLATITUDE CONVECTION; REACTIVE NITROGEN; OZONE PRODUCTION; ATMOSPHERIC NO2; HNO3/NOX RATIO; UNITED-STATES; PEM-TROPICS AB We present a statistical representation of the aggregate effects of deep convection on the chemistry and dynamics of the upper troposphere ( UT) based on direct aircraft observations of the chemical composition of the UT over the eastern United States and Canada during summer. These measurements provide unique observational constraints on the chemistry occurring downwind of convection and the rate at which air in the UT is recycled. These results provide quantitative measures that can be used to evaluate global climate and chemistry models. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. CALTECH, Div Chem & Chem Engn, Pasadena, CA 91125 USA. CALTECH, Div Engn & Appl Sci, Pasadena, CA 91125 USA. CALTECH, Div Geol & Planetary Sci, Pasadena, CA 91125 USA. Univ New Hampshire, Inst Study Earth Oceans & Space, Durham, NH 03824 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. Univ Hawaii Manoa, Sch Ocean & Earth Sci Technol, Honolulu, HI 96822 USA. Univ Maryland, Dept Atmospher & Ocean Sci, College Pk, MD 20742 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Florida State Univ, Dept Meteorol, Tallahassee, FL 32306 USA. Georgia Inst Technol, Sch Earth & Atmospher Sci, Atlanta, GA 30332 USA. Univ Calif Irvine, Dept Chem, Irvine, CA 92697 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Natl Ctr Atmospher Res, Boulder, CO 80305 USA. Univ Rhode Isl, Grad Sch Oceanog, Narragansett, RI 02882 USA. Univ Calif Berkeley, Dept Earth & Planetary Sci, Berkeley, CA 94720 USA. RP Cohen, RC (reprint author), Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. EM cohen@cchem.berkeley.edu RI Cohen, Ronald/A-8842-2011; Crounse, John/E-4622-2011; Wennberg, Paul/A-5460-2012; Pickering, Kenneth/E-6274-2012; Perring, Anne/G-4597-2013; Crawford, James/L-6632-2013; Crounse, John/C-3700-2014 OI Cohen, Ronald/0000-0001-6617-7691; Perring, Anne/0000-0003-2231-7503; Crawford, James/0000-0002-6982-0934; Crounse, John/0000-0001-5443-729X NR 50 TC 65 Z9 65 U1 2 U2 24 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 EI 1095-9203 J9 SCIENCE JI Science PD FEB 9 PY 2007 VL 315 IS 5813 BP 816 EP 820 DI 10.1126/science.1134548 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 134FN UT WOS:000244069000061 PM 17204609 ER PT J AU Loeb, NG Wielicki, BA Rose, FG Doelling, DR AF Loeb, Norman G. Wielicki, Bruce A. Rose, Fred G. Doelling, David R. TI Variability in global top-of-atmosphere shortwave radiation between 2000 and 2005 SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID ANGULAR-DISTRIBUTION MODELS; ENERGY SYSTEM INSTRUMENT; FLUX ESTIMATION; CLIMATE-CHANGE; PART I; SATELLITE; CLOUDS; METHODOLOGY AB [1] Measurements from various instruments and analysis techniques are used to directly compare changes in Earth-atmosphere shortwave (SW) top-of-atmosphere (TOA) radiation between 2000 and 2005. Included in the comparison are estimates of TOA reflectance variability from published ground-based Earthshine observations and from new satellite-based CERES, MODIS and ISCCP results. The ground-based Earthshine data show an order-of-magnitude more variability in annual mean SW TOA flux than either CERES or ISCCP, while ISCCP and CERES SW TOA flux variability is consistent to 40%. Most of the variability in CERES TOA flux is shown to be dominated by variations global cloud fraction, as observed using coincident CERES and MODIS data. Idealized Earthshine simulations of TOA SW radiation variability for a lunar-based observer show far less variability than the ground-based Earthshine observations, but are still a factor of 4-5 times more variable than global CERES SW TOA flux results. Furthermore, while CERES global albedos exhibit a well-defined seasonal cycle each year, the seasonal cycle in the lunar Earthshine reflectance simulations is highly variable and out-of-phase from one year to the next. Radiative transfer model (RTM) approaches that use imager cloud and aerosol retrievals reproduce most of the change in SW TOA radiation observed in broadband CERES data. However, assumptions used to represent the spectral properties of the atmosphere, clouds, aerosols and surface in the RTM calculations can introduce significant uncertainties in annual mean changes in regional and global SW TOA flux. C1 Hampton Univ, NASA, Langley Res Ctr, Hampton, VA 23681 USA. Analyt Serv & Mat Inc, Hampton, VA 23681 USA. RP Loeb, NG (reprint author), Hampton Univ, NASA, Langley Res Ctr, Mail Stop 420, Hampton, VA 23681 USA. EM n.g.loeb@larc.nasa.gov RI Richards, Amber/K-8203-2015; OI Rose, Fred G/0000-0003-0769-0772 NR 16 TC 24 Z9 24 U1 0 U2 7 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 EI 1944-8007 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD FEB 8 PY 2007 VL 34 IS 3 AR L03704 DI 10.1029/2006GL028196 PG 5 WC Geosciences, Multidisciplinary SC Geology GA 136DC UT WOS:000244201800003 ER PT J AU Zhou, XY Lummerzheim, D Gladstone, R Gunapala, S AF Zhou, X. -Y. Lummerzheim, D. Gladstone, R. Gunapala, S. TI Feasibility of observing dayside aurora using NIR camera onboard high-altitude balloons SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID ART.; SHOCKS; IMAGE AB [1] This letter reports a feasibility study on dayside auroral observation using a near-infrared (NIR) InGaAs camera from high-altitude, long-duration balloons. This effort is motivated by science interest in the dayside aurora. Model predictions indicate daytime observations are possible because the sky brightness significantly decreases towards longer wavelengths at certain altitude in the upper atmosphere, and the NIR ambient sky brightness substantially decreases with increasing altitude. To address the question whether aurora can indeed be detected in the upper atmosphere, auroral test observations were conducted at the Poker Flat Research Range from March 22 to April 26, 2005. The InGaAs camera used in this test covers a waveband from 900 to 1700 nm with a 320 x 256 focal plane array, 30 x 30 mu m pixels, and a 9 degrees field of view. For one evening event, we estimate the NIR sky brightness using the MODTRAN atmospheric radiance model and compare it with the expected sky brightness at 30-50 km altitudes. The comparison indicates that the N(2)(+) Meinel emission at similar to 1100 nm should be seen at 35-40 km altitudes and above, and therefore, confirms that such dayside auroral observations are feasible. Auroral studies using this method include, e. g., studies of interplanetary shock and pressure pulse induced auroras as well as conjugate auroras. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. SW Res Inst, San Antonio, TX USA. Univ Alaska, Inst Geophys, Fairbanks, AK 99775 USA. RP Zhou, XY (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM xiaoyan.zhou@jpl.nasa.gov NR 19 TC 2 Z9 3 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD FEB 8 PY 2007 VL 34 IS 3 AR L03105 DI 10.1029/2006GL028611 PG 5 WC Geosciences, Multidisciplinary SC Geology GA 136DC UT WOS:000244201800006 ER PT J AU Hauchecorne, A Bertaux, JL Dalaudier, F Russell, JM Mlynczak, MG Kyrola, E Fussen, D AF Hauchecorne, Alain Bertaux, Jean-Loup Dalaudier, Francis Russell, James M., III Mlynczak, Martin G. Kyrola, Erkki Fussen, Didier TI Large increase of NO2 in the north polar mesosphere in January-February 2004: Evidence of a dynamical origin from GOMOS/ENVISAT and SABER/TIMED data SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID SOLAR PROTON EVENTS; MIDDLE AB Odd nitrogen species play an important role in the stratospheric ozone balance through catalytic ozone destruction. A layer of strongly enhanced NO2 was detected in the north polar mesosphere by the GOMOS/ENVISAT stellar spectrometer in mid-January 2004. Large NO2 enhancements in the polar winter mesosphere have been previously reported by several authors and have been attributed to NO production by solar proton or by energetic electron precipitations. The simultaneous occurrence of an intense mesospheric warming observed by the SABER/TIMED instrument indicates that a strong air descent occurred in the polar region, transporting a large quantity of NO from the upper mesosphere-lower thermosphere to the lower mesosphere. The proposed mechanism may have a significant contribution to the budget of polar stratospheric ozone. C1 Univ Paris 06, Univ Versailles, Serv Aeron, Inst Pierre Simon Laplace,CNRS, F-91371 Verrieres Le Buisson, France. Hampton Univ, Ctr Atmospher Sci, Hampton, VA 23668 USA. NASA, Langley Res Ctr, Div Atmospher Sci, Hampton, VA 23681 USA. Finnish Meteorol Inst, FIN-00101 Helsinki, Finland. Inst Aeron Spatiale Belgique, B-1180 Brussels, Belgium. RP Hauchecorne, A (reprint author), Univ Paris 06, Univ Versailles, Serv Aeron, Inst Pierre Simon Laplace,CNRS, F-91371 Verrieres Le Buisson, France. EM alain.hauchecorne@aerov.jussieu.fr RI Mlynczak, Martin/K-3396-2012; Hauchecorne, Alain/A-8489-2013; Kyrola, Erkki/E-1835-2014; OI Hauchecorne, Alain/0000-0001-9888-6994 NR 23 TC 53 Z9 53 U1 1 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD FEB 7 PY 2007 VL 34 IS 3 AR L03810 DI 10.1029/2006GL027628 PG 5 WC Geosciences, Multidisciplinary SC Geology GA 136DA UT WOS:000244201600001 ER PT J AU Eckstein, MP Beutter, BR Pham, BT Shimozaki, SS Stone, LS AF Eckstein, Miguel P. Beutter, Brent R. Pham, Binh T. Shimozaki, Steven S. Stone, Leland S. TI Similar neural representations of the target for saccades and perception during search SO JOURNAL OF NEUROSCIENCE LA English DT Article DE visual search; eye movements; behavioral receptive fields; perception and action; decision; eye position ID VISUAL-SEARCH; EYE-MOVEMENT; RECEPTIVE-FIELDS; DISCRIMINATION; PERFORMANCE; DECISIONS; SELECTION; FEATURES; SIGNALS; VISION AB Are the body's actions and the mind's perceptions the result of shared neural processing, or are they performed largely independently? The brain has two major processing streams, and some have proposed that this division segregates visual processing for action and perception. The ventral pathway is claimed to support conscious experience (perception), whereas the dorsal pathway is claimed to support the control of movement (action). Others have argued that perception and action share much of their visual processing within the primate cortex. During visual search, the brain performs a sophisticated deployment of eye movements (saccadic actions) to gather information to subserve perceptual judgments. The relationship between the neural mechanisms mediating perception and action in visual search remains unexplored. Here, we investigate the visual representation of target information in the human brain, both for perceptual decisions and for saccadic actions during visual search. We use classification image analysis, a form of reverse correlation, to estimate the behavioral receptive fields of the visual mechanisms responsible for saccadic and perceptual responses during the same visual search task. Results show that the behavioral receptive fields mediating the perceptual decisions are indistinguishable from those driving the oculomotor decisions, suggesting that similar neural mechanisms are responsible for both perception and oculomotor action during search. Diverging target representations would result in an inefficient coupling between eye movement planning and perceptual judgments. Thus, a common target representation would be more optimal and might be expected to have evolved through natural selection in the neural systems responsible for visual search. C1 Univ Calif Santa Barbara, Dept Psychol, Vis & Image Understanding Lab, Santa Barbara, CA 93106 USA. NASA, Ames Res Ctr, Human Syst Integrat Div, Moffett Field, CA 94035 USA. RP Eckstein, MP (reprint author), Univ Calif Santa Barbara, Dept Psychol, Vis & Image Understanding Lab, Santa Barbara, CA 93106 USA. EM eckstein@psych.ucsb.edu FU NEI NIH HHS [5R01EY15925-2] NR 33 TC 37 Z9 37 U1 0 U2 3 PU SOC NEUROSCIENCE PI WASHINGTON PA 11 DUPONT CIRCLE, NW, STE 500, WASHINGTON, DC 20036 USA SN 0270-6474 J9 J NEUROSCI JI J. Neurosci. PD FEB 7 PY 2007 VL 27 IS 6 BP 1266 EP 1270 DI 10.1523/JNEUROSCI.3975-06.2007 PG 5 WC Neurosciences SC Neurosciences & Neurology GA 134FX UT WOS:000244070000007 PM 17287501 ER PT J AU Malkova, N Ning, CZ AF Malkova, N. Ning, C. Z. TI Tamm surface states in a finite chain of defects in a photonic crystal SO JOURNAL OF PHYSICS-CONDENSED MATTER LA English DT Article ID WAVE-GUIDE ARRAYS; MEDIA AB We present detailed theoretical and numerical studies of surface states of a coupled defect chain of finite length in a photonic crystal. By comparatively studying three such structures with zero, one, and two defects on the photonic crystal surface, respectively, we found that the transmission characteristics of the structure depend on the termination of the defect chain in the host crystal. The peak frequencies and the number of peaks are related to the boundary conditions of the coupled defects. Our numerical simulations in conjunction with analytical treatment using the coupled mode theory fully establish the analogy between the surface states in photonic crystals and the Tamm states in solids. We also point out how the results of the localized surface states in this one-dimensional model system can be generalized to two- or three-dimensional systems where surface states become surface waves. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Arizona State Univ, Dept Elect Engn, Ctr Nanophoton, Tempe, AZ 85287 USA. RP Malkova, N (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. EM nmalkova@mail.arc.nasa.gov; cning@asu.edu RI Ning, C. Z./D-4699-2009 OI Ning, C. Z./0000-0003-4583-8889 NR 27 TC 6 Z9 6 U1 0 U2 6 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0953-8984 J9 J PHYS-CONDENS MAT JI J. Phys.-Condes. Matter PD FEB 7 PY 2007 VL 19 IS 5 AR 056004 DI 10.1088/0953-8984/19/5/056004 PG 12 WC Physics, Condensed Matter SC Physics GA 130IB UT WOS:000243792200006 ER PT J AU Baker, JD Thompson, PM AF Baker, Jason D. Thompson, Paul M. TI Temporal and spatial variation in age-specific survival rates of a long-lived mammal, the Hawaiian monk seal SO PROCEEDINGS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES LA English DT Article DE Hawaiian monk seal; life history; survival; senescence; spatial variability; temporal variability ID TRICHECHUS-MANATUS-LATIROSTRIS; NATURAL-POPULATIONS; MCMURDO SOUND; LEPTONYCHOTES-WEDDELLII; MONACHUS-SCHAUINSLANDI; MARKED ANIMALS; FUR SEALS; SENESCENCE; ANTARCTICA; ABUNDANCE AB Estimates of variability in pinniped survival rates are generally based on observations at single sites, so it is not certain whether observed rates represent the whole population. Here, we provide a comprehensive analysis of spatio-temporal variation in age-specific survival rates for endangered Hawaiian monk seals (Monachus schauinslandi) based on capture-recapture analyses of more than 85% of the pups weaned in this population over the last two decades. Uniquely, these data have been collected from six subpopulations, encompassing all major breeding sites across its 1800 km long core range. Analyses of individual subpopulations revealed similar patterns in age-specific survival, characterized by the relatively low survival rates from weaning to 2 years of age, intermediate rates to 4 years of age, and then by relatively high 'mature' survival rates until 17 years of age, after which a senescent decline was observed. Juvenile, subadult and adult survival rates all varied significantly over time. Trends in survival among subpopulations were coherent with their relative geographical positions, suggesting regional structuring and connectedness within the archipelago. Survival rates for different age classes tended to be positively correlated, suggesting that similar factors may influence the survival for seals of all ages. C1 NOAA, Natl Marine fisheries Serv, Pacific Isl Fisheries Sci Ctr, Honolulu, HI 96822 USA. Univ Aberdeen, Sch Biol Sci, Cromarty IV11 8YJ, Ross, Scotland. RP Baker, JD (reprint author), NOAA, Natl Marine fisheries Serv, Pacific Isl Fisheries Sci Ctr, 2570 Dole St, Honolulu, HI 96822 USA. EM jason.baker@noaa.gov RI Thompson, Paul /B-6742-2009 OI Thompson, Paul /0000-0001-6195-3284 NR 41 TC 41 Z9 44 U1 2 U2 33 PU ROYAL SOC PI LONDON PA 6-9 CARLTON HOUSE TERRACE, LONDON SW1Y 5AG, ENGLAND SN 0962-8452 EI 1471-2954 J9 P ROY SOC B-BIOL SCI JI Proc. R. Soc. B-Biol. Sci. PD FEB 7 PY 2007 VL 274 IS 1608 BP 407 EP 415 DI 10.1098/rspb.2006.3737 PG 9 WC Biology; Ecology; Evolutionary Biology SC Life Sciences & Biomedicine - Other Topics; Environmental Sciences & Ecology; Evolutionary Biology GA 124FV UT WOS:000243354100013 PM 17164205 ER PT J AU Seo, EK Liu, G Tao, WK Han, SO AF Seo, Eun-Kyoung Liu, Guosheng Tao, Wei-Kuo Han, Sang-Ok TI Adaptation of a model-generated cloud database to satellite observations SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID ICE; PRECIPITATION; PARTICLES; DISTRIBUTIONS; MICROPHYSICS; RETRIEVALS; PROFILES; CIRRUS; RADAR AB Cloud resolving model outputs are often used to build databases for satellite microwave remote sensing of precipitating clouds. A known problem of this approach is that cloud resolving models tend to systematically produce excessive amount of high density frozen hydrometeors, causing the cloud/radiation model database to have stronger scattering signatures at high microwave frequencies than those observed by satellite or airborne sensors. Consequently, it lowers the performance of the cloud and precipitation retrieval algorithms that utilize the model database. Since multi-frequency satellite observations contain information on hydrometeors' properties, measured brightness temperatures can give guidance as to how the modeled cloud database may be modified to better mimic natural clouds. Following this philosophy, in this study, we propose a method to adapt the modeled database toward observations. The newly constructed database results in a better match to the characteristics of the satellite observed brightness temperatures. C1 Florida State Univ, Dept Meteorol, Tallahassee, FL 32306 USA. Seoul Natl Univ, Sch Earth & Environm Sci, Seoul, South Korea. NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. Texas A&M Univ, College Stn, TX 77843 USA. RP Seo, EK (reprint author), Florida State Univ, Dept Meteorol, 404 Love Bldg, Tallahassee, FL 32306 USA. EM eunkyoungseo@gmail.com RI Liu, Guosheng/D-3479-2011; Measurement, Global/C-4698-2015 OI Liu, Guosheng/0000-0001-7899-6125; NR 19 TC 8 Z9 8 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD FEB 3 PY 2007 VL 34 IS 3 AR L03805 DI 10.1029/2006GL027857 PG 5 WC Geosciences, Multidisciplinary SC Geology GA 133VE UT WOS:000244041200002 ER PT J AU Tselioudis, G Kollias, P AF Tselioudis, George Kollias, Pavlos TI Evaluation of ECMWF cloud type simulations at the ARM Southern Great Plains site using a new cloud type climatology SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID RADIATION MEASUREMENT PROGRAM; VERTICAL STRUCTURE; MODEL EVALUATION AB A new method to derive a cloud type climatology is applied to cloud observations over the Southern Great Plains (SGP) Atmospheric Radiation Measurement ( ARM) site and to ECMWF model forecasts, in order to compare model and radar derived cloud type statistics and identify the major deficiencies in model cloud vertical distribution. The results indicate that cirrus and to a lesser extent middle level clouds are the major cloud types missing in the model simulations and that they are missing mostly as parts of multi-type rather than single-type structures. Boundary layer clouds are simulated at approximately the right amounts in the annual mean statistics, but this result comes from the model simulating too little boundary layer cloud in the winter and too much in the summer. Overall, the model forecasts miss about 11% of the total cloud amount, and most of the missing cloud occurs at time periods when multiple cloud types are present in the observations. C1 NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Columbia Univ, Dept Appl Phys, New York, NY 10027 USA. Brookhaven Natl Lab, Div Atmospher Sci, Upton, NY 11973 USA. RP Tselioudis, G (reprint author), NASA, Goddard Inst Space Studies, 2880 Broadway, New York, NY 10025 USA. EM gtselioudis@giss.nasa.gov NR 15 TC 3 Z9 3 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 EI 1944-8007 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD FEB 3 PY 2007 VL 34 IS 3 AR L03803 DI 10.1029/2006GL027314 PG 5 WC Geosciences, Multidisciplinary SC Geology GA 133VE UT WOS:000244041200001 ER PT J AU Brown, MV Donachie, SP AF Brown, Mark V. Donachie, Stuart P. TI Evidence for tropical endemicity in the Deltaproteobacteria Marine Group B/SAR324 bacterioplankton clade SO AQUATIC MICROBIAL ECOLOGY LA English DT Article DE Marine Group B; SAR324; biogeography; internal transcribed spacer; ITS ID INTERGENIC SPACER ANALYSIS; BACTERIAL COMMUNITIES; MICROBIAL DIVERSITY; DEEP-SEA; MEDITERRANEAN SEA; NORTH-ATLANTIC; PACIFIC-OCEAN; SAR11 CLUSTER; SARGASSO SEA; TIME-SERIES AB The fine-scale phylogeny of the deeply branching Deltaproteobacteria Marine Group B/SAR324 (MGB/SAR324) bacterioplankton clade was analyzed using partial 16S rRNA gene sequence and internal transcribed spacer (ITS) sequences. Both sets of analyses revealed considerable sequence variation, which, along with bootstrap calculations, strongly support the discrimination of 3 'species' level clusters (i.e. displaying < 98% within-cluster and > 97% between-cluster 16S rRNA gene sequence identity) within this clade, which are here designated as MGB/SAR324 clade groups I and II and the MGB/SAR276 clade. The biogeographical ranges of these 3 clades were analyzed using newly acquired 16S and ITS sequences from Stn ALOHA (22.45 degrees N, 158 degrees W), along with sequences available in the public domain. MGB/SAR324 clade group I and the MBG/SAR276 clade display a clearly restricted distribution, occurring only in tropical and subtropical waters at depths < 250 m. These groups represent the first reported species- and genus-level phylotypes displaying a 'tropical-only' global distribution. MGB/SAR324 clade group II, which has been previously described as ubiquitous, occurs across the latitudinal gradient, but is generally restricted to deep, colder waters in the lower latitudes. Enzyme sequences associated at least with MGB/SAR324 clade group II appear to indicate a role for this group in dissolved organic phosphate cycling. C1 Univ Hawaii, NASA, Astrobiol Inst, Honolulu, HI 96822 USA. Univ Hawaii, Dept Microbiol, Honolulu, HI 96822 USA. RP Brown, MV (reprint author), Univ Hawaii, NASA, Astrobiol Inst, PSB211,2565 McCarthy Hall, Honolulu, HI 96822 USA. EM mbrown@ifa.hawaii.edu NR 33 TC 11 Z9 11 U1 1 U2 6 PU INTER-RESEARCH PI OLDENDORF LUHE PA NORDBUNTE 23, D-21385 OLDENDORF LUHE, GERMANY SN 0948-3055 J9 AQUAT MICROB ECOL JI Aquat. Microb. Ecol. PD FEB 2 PY 2007 VL 46 IS 2 BP 107 EP 115 DI 10.3354/ame046107 PG 9 WC Ecology; Marine & Freshwater Biology; Microbiology SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Microbiology GA 139IZ UT WOS:000244426800001 ER PT J AU Williams, JG Turyshev, SG Boggs, DH AF Williams, James G. Turyshev, Slava G. Boggs, Dale H. TI Comment on "progress in lunar laser ranging tests of relativistic gravity" - Reply SO PHYSICAL REVIEW LETTERS LA English DT Editorial Material C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Williams, JG (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 10 TC 12 Z9 12 U1 0 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD FEB 2 PY 2007 VL 98 IS 5 AR 059002 DI 10.1103/PhysRevLett.98.059002 PG 1 WC Physics, Multidisciplinary SC Physics GA 142JR UT WOS:000244646100087 ER PT J AU Stenger, MB Evans, JM Patwardhan, AR Moore, FB Hinghofer-Szalkay, H Rossler, A Ziegler, MG Knapp, CF AF Stenger, Michael B. Evans, Joyce M. Patwardhan, Abhijit R. Moore, Fritz B. Hinghofer-Szalkay, Helmut Roessler, Andreas Ziegler, Michael G. Knapp, Charles F. TI Artificial gravity training improves orthostatic tolerance in ambulatory men and women SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT 15th IAA Humans in Space Symposium CY 2005 CL Graz, AUSTRIA SP Inst Adapt & Spaceflight Physiol DE artificial gravity; centrifuge; countermeasure; gender ID BODY NEGATIVE-PRESSURE; CARDIOVASCULAR-RESPONSES; ACCELERATION; HYPOTENSION; CENTRIFUGE; MECHANISMS AB Orthostatic intolerance (01) continues to be a problem experienced by astronauts upon return from spaceflight. Artificial gravity (AG) training via short radius centrifugation has been suggested as a countermeasure to this OI. The purpose of our research was to determine effects of three weeks of intermittent (+1 to +2.5 G(Z) for 35 min/day) AG exposure on normal, ambulatory men and women. The results of this study indicate that 3 weeks of AG training improved orthostatic tolerance in a group of 14 men and 12 women by an average of 13.6%. This improvement was associated with a decrease in arterial pressure and vascular resistance, and increases in stroke volume and low frequency (0.04-0.15 Hz) arterial pressure and heart rate spectral power. These results suggest that improvement may be attributable to increased venous return possibly as a function of increased stress-induced sympathetic activity and/or vascular sympathetic responsiveness. (c) 2006 Elsevier Ltd. All rights reserved. C1 Univ Kentucky, Ctr Biomed Engn, Lexington, KY 40506 USA. NASA, Ames Ctr Biol & Gravitat Res, Moffett Field, CA 94035 USA. Inst Adapt & Spaceflight Physiol, A-8010 Graz, Austria. Med Univ, Ctr Physiol Med, Inst Physiol, A-8010 Graz, Austria. Univ Calif San Diego, Gen Clin Res Ctr, San Diego, CA 92103 USA. RP Stenger, MB (reprint author), Univ Kentucky, Ctr Biomed Engn, Lexington, KY 40506 USA. EM michael.b.stenger@nasa.gov RI Roessler, Andreas/A-5751-2008 NR 13 TC 9 Z9 10 U1 0 U2 5 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0094-5765 J9 ACTA ASTRONAUT JI Acta Astronaut. PD FEB-APR PY 2007 VL 60 IS 4-7 BP 267 EP 272 DI 10.1016/j.actaastro.2006.08.008 PG 6 WC Engineering, Aerospace SC Engineering GA 144NA UT WOS:000244801900008 ER PT J AU White, RJ McPhee, JC AF White, Ronald J. McPhee, Jancy C. TI The Digital Astronaut: An integrated modeling and database system for space biomedical research and operations SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT 15th IAA Humans in Space Symposium CY 2005 CL Graz, AUSTRIA SP Inst Adapt & Spaceflight Physiol DE physiological modeling; decision support; countermeasure; weightlessness ID SLS-1 AB The Digital Astronaut is an integrated, modular modeling and database system that will support space biomedical research and operations in a variety of fundamental ways. This system will enable the identification and meaningful interpretation of the medical and physiological research required for human space exploration, a determination of the effectiveness of specific individual human countermeasures in reducing risk and meeting health and performance goals on challenging exploration missions and an evaluation of the appropriateness of various medical interventions during mission emergencies, accidents and illnesses. Such a computer-based, decision support system will enable the construction, validation and utilization of important predictive simulations of the responses of the whole human body to the types of stresses experienced during space flight and low-gravity environments. These simulations will be essential for direct, real-time analysis and maintenance of astronaut health and performance capabilities. The Digital Astronaut will collect and integrate past and current human data across many physiological disciplines and simulations into an operationally useful form that will not only summarize knowledge in a convenient and novel way but also reveal gaps that must be filled via new research in order to effectively ameliorate biomedical risks. Initial phases of system development will focus on simulating ground-based analog systems that are just beginning to collect multidisciplinary data in a standardized way (e.g., the International Multidisciplinary Artificial Gravity Project). During later phases, the focus will shift to development and planning for missions and to exploration mission operations. Then, the Digital Astronaut system will enable evaluation of the effectiveness of multiple, simultaneously applied countermeasures (a task made difficult by the many-system physiological effects of individual countermeasures) and allow for the prescription of individualized astronaut countermeasures. Additionally, during exploration missions, this system will support autonomous and telemedicine-assisted health and performance assessment and medical care. (c) 2006 Elsevier Ltd. All rights reserved. C1 Univ Space Res Assoc, Div Space Life Sci, Houston, TX 77058 USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP White, RJ (reprint author), Univ Space Res Assoc, Div Space Life Sci, 3600 Bay Area Blvd, Houston, TX 77058 USA. EM white@dsls.usra.edu NR 14 TC 0 Z9 0 U1 1 U2 4 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0094-5765 J9 ACTA ASTRONAUT JI Acta Astronaut. PD FEB-APR PY 2007 VL 60 IS 4-7 BP 273 EP 280 DI 10.1016/j.actaastro.2006.08.009 PG 8 WC Engineering, Aerospace SC Engineering GA 144NA UT WOS:000244801900009 ER PT J AU Wu, H Hartman, MR Udovic, TJ Rush, JJ Zhou, W Bowman, RC Vajo, JJ AF Wu, Hui Hartman, Michael R. Udovic, Terrence J. Rush, John J. Zhou, Wei Bowman, Robert C., Jr. Vajo, John J. TI Structure of the novel ternary hydrides Li(4)Tt(2)D (Tt = Si and Ge) SO ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE LA English DT Article ID X-RAY; NEUTRON-DIFFRACTION; POWDER DIFFRACTION; PHASE; SYSTEM; RINGS; ND AB The crystal structures of newly discovered Li4Ge2D and Li4Si2D ternary phases were solved by direct methods using neutron powder diffraction data. Both structures can be described using a Cmmm orthorhombic cell with all hydrogen atoms occupying Li-6-octahedral interstices. The overall crystal structure and the geometry of these interstices are compared with those of other related phases, and the stabilization of this novel class of ternary hydrides is discussed. C1 Natl Inst Standards & Technol, NIST Ctr Neutron Res, Gaithersburg, MD 20899 USA. Univ Maryland, Dept Mat Sci & Engn, College Pk, MD 20742 USA. Oregon State Univ, Dept Nucl Engn & Radiat Hlth Phys, Corvallis, OR 97331 USA. Univ Penn, Dept Mat Sci & Engn, Philadelphia, PA 19104 USA. CALTECH, Jet Propuls Lab, Pasadena, CA USA. LLC, HRL Labs, Malibu, CA 90265 USA. RP Wu, H (reprint author), Natl Inst Standards & Technol, NIST Ctr Neutron Res, Gaithersburg, MD 20899 USA. EM huiwu@nist.gov RI Wu, Hui/C-6505-2008; Zhou, Wei/C-6504-2008 OI Wu, Hui/0000-0003-0296-5204; Zhou, Wei/0000-0002-5461-3617 NR 25 TC 15 Z9 15 U1 1 U2 3 PU BLACKWELL PUBLISHING PI OXFORD PA 9600 GARSINGTON RD, OXFORD OX4 2DQ, OXON, ENGLAND SN 0108-7681 J9 ACTA CRYSTALLOGR B JI Acta Crystallogr. Sect. B-Struct. Sci. PD FEB PY 2007 VL 63 BP 63 EP 68 DI 10.1107/S0108768106046465 PN 1 PG 6 WC Chemistry, Multidisciplinary; Crystallography SC Chemistry; Crystallography GA 140QQ UT WOS:000244521100008 PM 17235195 ER PT J AU Yoon, KE Noebe, RD Seidman, DN AF Yoon, Kevin E. Noebe, Ronald D. Seidman, David N. TI Effects of rhenium addition on the temporal evolution of the nanostructure and chemistry of a model Ni-Cr-Al superalloy. I: Experimental observations SO ACTA MATERIALIA LA English DT Article DE nickel alloys; rhenium; atom probe tomography; nanostructure; segregation ID 3-DIMENSIONAL ATOM-PROBE; NICKEL-BASE SUPERALLOYS; BEAM ELECTRON-DIFFRACTION; LOCAL ELASTIC STRAINS; INTERFACIAL EXCESS; GAMMA' PRECIPITATE; ALLOYS; MICROSCOPY; ENERGY; MICROSTRUCTURE AB The temporal evolution of the nanostructure and chemistry of a model Ni-8.5 at.% Cr-10 at.% A] alloy, with the addition of 2 at.% Re, aged at 1073 K from 0.25 to 264 h, was studied. Transmission electron microscopy and atom-probe tomography were used to measure the number density and mean radius of the gamma' (L1(2) structure)-precipitates and the chemistry of the gamma'-precipitates and the gamma (face-centered cubic)-matrix, including the partitioning behavior of all alloying elements between the gamma- and gamma'-phases and the segregation behavior at gamma/gamma' interfaces. The precipitates remained spheroidal for an aging time of up to 264 h and, unlike commercial nickel-based superalloys containing Re, there was not confined (nonmonotonic) Re segregation at the gamma/gamma' interfaces. (c) 2006 Published by Elsevier Ltd on behalf of Acta Materialia Inc. C1 Northwestern Univ, Dept Mat Sci & Engn, Evanston, IL 60208 USA. NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Seidman, DN (reprint author), Northwestern Univ, Dept Mat Sci & Engn, Evanston, IL 60208 USA. EM d-seidman@northwestern.edu RI Seidman, David/B-6697-2009 NR 55 TC 33 Z9 35 U1 0 U2 11 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1359-6454 J9 ACTA MATER JI Acta Mater. PD FEB PY 2007 VL 55 IS 4 BP 1145 EP 1157 DI 10.1016/j.actamat.2006.08.027 PG 13 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 141AJ UT WOS:000244548100003 ER PT J AU Yoon, KE Noebe, RD Seidman, DN AF Yoon, Kevin E. Noebe, Ronald D. Seidman, David N. TI Effects of rhenium addition on the temporal evolution of the nanostructure and chemistry of a model Ni-Cr-Al superalloy. II: Analysis of the coarsening behavior SO ACTA MATERIALIA LA English DT Article DE nickel alloys; rhenium; atom probe tomography; nanostructure; coarsening; Umantsev-Olson model ID BIMODAL SIZE DISTRIBUTIONS; BASE SUPERALLOYS; ATOM-PROBE; ALLOYS; RE; PRECIPITATE; KINETICS; TA; MO AB The temporal evolution of the nanostructure and chemistry of a model Ni-8.5 at.% Cr-10 at.% Al alloy with the addition of 2 at-% Re was studied using transmission electron microscopy and atom-probe tomography in order to measure the number density and mean radius of the gamma' (L1(2)) precipitates and the chemistry of the gamma'-precipitates and the gamma (fcc)-matrix. In this article, the coarsening behavior of the gamma'-precipitates is discussed in detail and compared with the Umantsev-Olson model for multi-component alloys. In addition, the experimental results are evaluated with PrecipiCalc (TM) simulations. The results show that the diffusivities of the solute elements play a major role in the coarsening behavior of the gamma'-precipitates and that the addition of Re retards the coarsening kinetics and stabilizes the spheroidal morphology of the precipitates by reducing the interfacial energy. (c) 2006 Published by Elsevier Ltd on behalf of Acta Materialia Inc. C1 Northwestern Univ, Dept Mat Sci & Engn, Evanston, IL 60208 USA. NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Seidman, DN (reprint author), Northwestern Univ, Dept Mat Sci & Engn, Evanston, IL 60208 USA. EM d-seidman@northwestern.edu RI Seidman, David/B-6697-2009 NR 34 TC 33 Z9 34 U1 1 U2 10 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1359-6454 J9 ACTA MATER JI Acta Mater. PD FEB PY 2007 VL 55 IS 4 BP 1159 EP 1169 DI 10.1016/j.actamat.2006.08.024 PG 11 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 141AJ UT WOS:000244548100004 ER PT J AU Ikeda, T Haile, SM Ravi, VA Azizgolshani, H Gascoin, F Snyder, GJ AF Ikeda, Teruyuki Haile, Sossina M. Ravi, Vilupanur A. Azizgolshani, Hesham Gascoin, Franck Snyder, G. Jeffrey TI Solidification processing of alloys in the pseudo-binary PbTe-Sb2Te3 system SO ACTA MATERIALIA LA English DT Article DE thermoelectric; solidification microstructure; dendritic growth; scanning electron microscopy ID GROWTH; ALUMINUM; SB2TE3 AB The effects of composition and cooling rate on the microstructures of alloys in the pseudo-binary PbTe-Sb2Te3 system were investigated as a first step towards the design of nanostructured materials with enhanced thermoelectric properties. Liquid alloys of three different compositions were cooled in three distinct ways: water quenching, air cooling and furnace cooling. The resultant structures and phases were examined by electron microscopy, electron microprobe chemical analysis and electron backscatter diffraction. The compound Pb2Sb6Te11 precipitated as a metastable phase (in conjunction with PbTe and/or Sb2Te3) under all conditions. Furthermore, whereas PbTe exhibited dendritic morphology, Sb2Te3 and Pb2Sb6Te11 I crystallized as lamellar platelets with preferred (00 1) orientation. The range of cooling rates was from similar to 1 to 26 K/s, while the characteristic microstructural feature size ranged from 10 to 35 pm for dendrites, and from 15 to 50 mu m for lamella. The prospects for achieving nanoscale structure are discussed. (c) 2006 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved. C1 CALTECH, Pasadena, CA 91125 USA. Calif State Polytech Univ Pomona, Dept Chem & Mat Engn, Pomona, CA 91768 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Haile, SM (reprint author), CALTECH, 1200 E Colorado Blvd, Pasadena, CA 91125 USA. EM smhaile@caltech.edu RI Snyder, G. Jeffrey/E-4453-2011; Ikeda, Teruyuki/J-6176-2014; Snyder, G/I-2263-2015; Haile, Sossina/I-3448-2015 OI Snyder, G. Jeffrey/0000-0003-1414-8682; Ikeda, Teruyuki/0000-0001-7076-6958; NR 30 TC 51 Z9 51 U1 0 U2 27 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1359-6454 EI 1873-2453 J9 ACTA MATER JI Acta Mater. PD FEB PY 2007 VL 55 IS 4 BP 1227 EP 1239 DI 10.1016/j.actamat.2006.09.036 PG 13 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 141AJ UT WOS:000244548100010 ER PT J AU McNaughton, CS Clarke, AD Howell, SG Pinkerton, M Anderson, B Thornhill, L Hudgins, C Winstead, E Dibb, JE Scheuer, E Maring, H AF McNaughton, Cameron S. Clarke, Antony D. Howell, Steven G. Pinkerton, Mitchell Anderson, Bruce Thornhill, Lee Hudgins, Charlie Winstead, Edward Dibb, Jack E. Scheuer, Eric Maring, Hal TI Results from the DC-8 Inlet Characterization Experiment (DICE): Airborne versus surface sampling of mineral dust and sea salt aerosols SO AEROSOL SCIENCE AND TECHNOLOGY LA English DT Article ID PACIFIC EXPLORATORY MISSION; PEM-TROPICS-B; PASSING EFFICIENCY; INTEGRATING NEPHELOMETER; LEAD 210; AIRCRAFT; DISTRIBUTIONS; PERFORMANCE; PARTICLES; TRANSPORT AB During May and June of 2003 NASA conducted the DC-8 Inlet Characterization Experiment (DICE). The study was undertaken to quantify the performance of three passive, solid diffuser inlets used aboard the DC-8 aircraft to sample optically effective aerosol sizes. Aerosol optical properties measured behind the University of Hawai'i (UH) and the University of New Hampshire (UNH) inlets were within 10% of the ground based measurements whereas the NASA Langley (LaRC) inlet reduced scattering values for supermicrometer dust by approximately 50%. Based on the DICE results the aerodynamic 50% passing efficiency of the inlets and transport plumbing is determined to be above 5.0 and 4.1 mu m for the UH and UNH inlets and 3.6 mu m for the LaRC inlet. These aerodynamic sizes correspond to geometric particle diameters of 3.1, 2.5, and 2.0 mu m ignoring shape factor and assuming particle densities of 2.6 g cm(-3). Sea salt aerosols sampled at high relative humidity revealed that the UH and the UNH inlets performed nearly identically in the marine environment. Aerosol optical properties measured behind the UH inlet were within 30% of measurements made at the NOAA/ESRL Trinidad Head Observatory and in some cases were better than 10%. We conclude that quantitative measurements of optical properties and processes linked to aerosol surface chemistry can be effectively studied aboard the NASA DC-8 using the UH and UNH inlets because aerosol particles less than 4 mu m in aerodynamic diameter typically dominate aerosol optical properties and surface area. C1 Univ Hawaii, Dept Oceanog, Sch Ocean & Earth Sci & Technol, Honolulu, HI 96822 USA. NASA, Langley Res Ctr, Hampton, VA 23665 USA. SAIC, Hampton, VA USA. GATS Inc, Hampton, VA USA. Univ New Hampshire, Inst Study Earth Oceans & Space, Durham, NH 03824 USA. NASA Headquarters, Washington, DC USA. RP McNaughton, CS (reprint author), Univ Hawaii, Dept Oceanog, Sch Ocean & Earth Sci & Technol, 1000 Pope Rd, Honolulu, HI 96822 USA. EM csmcnaug@hawaii.edu NR 48 TC 69 Z9 69 U1 1 U2 13 PU TAYLOR & FRANCIS INC PI PHILADELPHIA PA 530 WALNUT STREET, STE 850, PHILADELPHIA, PA 19106 USA SN 0278-6826 EI 1521-7388 J9 AEROSOL SCI TECH JI Aerosol Sci. Technol. PD FEB PY 2007 VL 41 IS 2 BP 136 EP 159 DI 10.1080/02786820601118406 PG 24 WC Engineering, Chemical; Engineering, Mechanical; Environmental Sciences; Meteorology & Atmospheric Sciences SC Engineering; Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA 140TJ UT WOS:000244529300004 ER PT J AU Kuzmanoski, M Box, MA Box, GP Schmid, B Wang, J Russell, PB Jonsson, HH Seinfeld, JH AF Kuzmanoski, M. Box, M. A. Box, G. P. Schmid, B. Wang, J. Russell, P. B. Jonsson, H. H. Seinfeld, J. H. TI Aerosol properties computed from aircraft-based observations during the ACE-Asia campaign: 1. Aerosol size distributions retrieved from optical thickness measurements SO AEROSOL SCIENCE AND TECHNOLOGY LA English DT Article ID LOWER TROPOSPHERIC AEROSOL; AIRBORNE IN-SITU; RADIATIVE PROPERTIES; WATER-VAPOR; EXTINCTION MEASUREMENTS; COLUMN CLOSURE; PARTICLE-SIZE; UNITED-STATES; MINERAL DUST; INVERSION AB In this article, aerosol size distributions retrieved from aerosol layer optical thickness spectra, derived from the 14-channel NASA Ames Airborne Tracking Sunphotometer (AATS-14) measurements during the ACE-Asia campaign, are presented. Focusing on distinct aerosol layers (with different particle characteristics) observed in four vertical profiles, we compare the results of two different retrieval methods: constrained linear inversion and a nonlinear least squares method. While the former does not use any assumption about the analytical form of the size distribution, the latter was used to retrieve parameters of a bimodal lognormal size distribution. Furthermore, comparison of the retrieved size distributions with those measured in-situ, aboard the same aircraft on which the sunphotometer was flown, was carried out. Results of the two retrieval methods showed good agreement in the radius ranges from similar to 0.1 mu m to similar to 1.2-2.0 mu m, close to the range of retrievable size distributions from the AATS-14 measurements. In this radius interval, shapes of retrieved and measured size distributions were similar, in accord with close wavelength dependencies of the corresponding optical thicknesses. Additionally, the effect of a size-resolved refractive index on the retrieved size spectra was investigated in selected cases. Retrieval using a constant refractive index pertaining to particle sizes within the range of retrievable size distributions resulted in a size distribution very close to the one retrieved using a size-resolved refractive index. C1 Univ New S Wales, Sch Phys, Sydney, NSW 2052, Australia. Bay Area Environm Res Inst, Sonoma, CA USA. Brookhaven Natl Lab, New York, NY USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Ctr Interdisciplinary Remotely Piloted Aircraft S, Marina, CA USA. CALTECH, Dept Chem Engn, Pasadena, CA 91125 USA. RP Kuzmanoski, M (reprint author), Univ New S Wales, Sch Phys, Sydney, NSW 2052, Australia. EM mkuzm@phys.unsw.edu.au RI Wang, Jian/G-9344-2011 NR 45 TC 3 Z9 3 U1 0 U2 2 PU TAYLOR & FRANCIS INC PI PHILADELPHIA PA 325 CHESTNUT ST, SUITE 800, PHILADELPHIA, PA 19106 USA SN 0278-6826 J9 AEROSOL SCI TECH JI Aerosol Sci. Technol. PD FEB PY 2007 VL 41 IS 2 BP 202 EP 216 DI 10.1080/02786820601126789 PG 15 WC Engineering, Chemical; Engineering, Mechanical; Environmental Sciences; Meteorology & Atmospheric Sciences SC Engineering; Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA 140TJ UT WOS:000244529300008 ER PT J AU Wright, MJ Bose, D Chen, YK AF Wright, Michael J. Bose, Deepak Chen, Y. -K. TI Probabilistic Modeling of aerothermal and thermal protection material response uncertainties SO AIAA JOURNAL LA English DT Article ID CHEMICAL-KINETIC PROBLEMS; SAMPLE RETURN CAPSULE; FUTURE NASA MISSIONS; TEMPERATURE DATA; MARS ENTRIES; ABLATION; DESIGN; AEROCAPTURE; EXPERIENCE; RADIATION AB A Monte-Carlo-based methodology is presented for physics-based Probabilistic uncertainty analysis of aerothermodynamics and thermal protection system (TPS) material response modeling for aerocapture or direct entry missions. The objective of the methodology is to identify and quantify the most important sources of uncertainty in aeroheating and the resulting thermal protection material selection, design, and sizing based on inaccuracies in current knowledge of the parametric input modeling parameters. The resulting parametric modeling uncertainty would be combined with other uncertainty sources to determine the final aeroheating and TPS response modeling uncertainty for a given application, which can then be used to define appropriate margins and factors of safety that should be applied to the TPS. These techniques facilitate a risk-based probabilistic design approach, whereby the thermal protection system can be designed to a desired risk tolerance, and any remaining risk can be effectively compared to that of other subsystems via a system-level risk mitigation analysis. Modeling sensitivities, which are a byproduct of the uncertainty analysis, can be used to rank input uncertainty drivers. Key input uncertainties can then be prioritized and targeted for further analysis or testing. The strengths and limitations of this technique are discussed. Sample results are presented for two cases: Titan aerocapture and Mars Pathfinder. These cases demonstrate the utility of the methodology to quantify the uncertainty levels, rank sources of input uncertainty, and assist in the identification of structural uncertainties in the models employed. C1 NASA, Ames Res Ctr, Reacting Flow Environm Branch, Moffett Field, CA 94035 USA. NASA, Ames Res Ctr, ELORET Corp, Moffett Field, CA 94035 USA. NASA, Ames Res Ctr, Thermal Protect Mat & Syst Branch, Moffett Field, CA 94035 USA. RP Wright, MJ (reprint author), NASA, Ames Res Ctr, Reacting Flow Environm Branch, MS 230-2, Moffett Field, CA 94035 USA. NR 54 TC 13 Z9 15 U1 0 U2 4 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0001-1452 J9 AIAA J JI AIAA J. PD FEB PY 2007 VL 45 IS 2 BP 399 EP 410 DI 10.2514/1.26018 PG 12 WC Engineering, Aerospace SC Engineering GA 135IB UT WOS:000244146200010 ER PT J AU Nauman, EA Ott, CM Sander, E Tucker, DL Pierson, D Wilson, JW Nickerson, CA AF Nauman, Eric A. Ott, C. Mark Sander, Ed Tucker, Don L. Pierson, Duane Wilson, James W. Nickerson, Cheryl A. TI Novel quantitative biosystem for modeling physiological fluid shear stress on cells SO APPLIED AND ENVIRONMENTAL MICROBIOLOGY LA English DT Article ID ENTERICA SEROVAR TYPHIMURIUM; ROTATING-WALL VESSEL; SIMULATED MICROGRAVITY; ESCHERICHIA-COLI; BACTERIAL ADHESION; GENE-EXPRESSION; ENVIRONMENTS; BIOREACTOR; ERYTHROCYTES; RESISTANCE AB The response of microbes to changes in the mechanical force of fluid shear has important implications for pathogens, which experience wide fluctuations in fluid shear in vivo during infection. However, the majority of studies have not cultured microbes under physiological fluid shear conditions within a range commonly encountered by microbes during host-pathogen interactions. Here we describe a convenient batch culture biosystem in which (i) the levels of fluid shear force can be varied within physiologically relevant ranges and quantified via mathematical models and (ii) large numbers of cells can be planktonically grown and harvested to examine the effect of fluid shear levels on microbial genomic and phenotypic responses. A quantitative model based on numerical simulations and in situ imaging analysis was developed to calculate the fluid shear imparted by spherical beads of different sizes on bacterial cell cultures grown in a rotating wall vessel (RWV) bioreactor. To demonstrate the application of this model, we subjected cultures of the bacterial pathogen Salmonella enterica serovar Typhimurium to three physiologically-relevant fluid shear ranges during growth in the RVW and demonstrated a progressive relationship between the applied fluid shear and the bacterial genetic and phenotypic responses. By applying this model to different cell types, including other bacterial pathogens, entire classes of genes and proteins involved in cellular interactions may be discovered that have not previously been identified during growth under conventional culture conditions, leading to new targets for vaccine and therapeutic development. C1 Purdue Univ, Sch Mech Engn, Weldon Sch Biomed Engn, W Lafayette, IN 47907 USA. NASA, Lyndon B Johnson Space Ctr, Habitabil & Environm Factors Div, Houston, TX 77058 USA. Univ Space Res Assoc, Div Space Life Sci, Houston, TX 77058 USA. Tulane Univ, Tulane Ctr Excellence Bioengn, Dept Microbiol & Immunol, Program Mol Pathogenesis & Immunity,Ctr Hlth Sci, New Orleans, LA 70112 USA. RP Nickerson, CA (reprint author), Arizona State Univ, Ctr Infect Dis & Viaccinol, Biodesign Inst, POB 875401, Tempe, AZ 85287 USA. EM cheryl.nickerson@asu.edu NR 33 TC 31 Z9 34 U1 3 U2 19 PU AMER SOC MICROBIOLOGY PI WASHINGTON PA 1752 N ST NW, WASHINGTON, DC 20036-2904 USA SN 0099-2240 J9 APPL ENVIRON MICROB JI Appl. Environ. Microbiol. PD FEB PY 2007 VL 73 IS 3 BP 699 EP 705 DI 10.1128/AEM.02428-06 PG 7 WC Biotechnology & Applied Microbiology; Microbiology SC Biotechnology & Applied Microbiology; Microbiology GA 136ZY UT WOS:000244263800005 PM 17142365 ER PT J AU Maun, JD Sunderland, PB Urban, DL AF Maun, Jignesh D. Sunderland, Peter B. Urban, David L. TI Thin-filament pyrometry with a digital still camera SO APPLIED OPTICS LA English DT Article ID TEMPERATURE-PROFILE MEASUREMENTS; DIFFUSION FLAMES; WIRE AB A novel thin-filament pyrometer is presented. It involves a consumer-grade color digital still camera with 6 megapixels and 12 bits per color plane. SiC fibers were used and scanning-electron microscopy found them to be uniform with diameters of 13.9 mu m. Measurements were performed in a methane-air coflowing laminar jet diffusion flame with a luminosity length of 72 mm. Calibration of the pyrometer was accomplished with B-type thermocouples. The pyrometry measurements yielded gas temperatures in the range of 1400-2200 K with an estimated uncertainty of +/- 60 K, a relative temperature resolution of +/- 0.215 K, a spatial resolution of 42 mu m, and a temporal resolution of 0.66 ms. Fiber aging for 10 min had no effect on the results. Soot deposition was less problematic for the pyrometer than for the thermocouple. C1 Univ Maryland, Dept Fire Protect Engn, College Pk, MD 20742 USA. NASA, Glenn Res Ctr, Combusting & Reacting Syst Branch, Cleveland, OH 44135 USA. RP Maun, JD (reprint author), Univ Maryland, Dept Fire Protect Engn, College Pk, MD 20742 USA. EM pbs@umd.edu OI Sunderland, Peter/0000-0002-8262-7100 NR 23 TC 10 Z9 10 U1 0 U2 3 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1559-128X EI 2155-3165 J9 APPL OPTICS JI Appl. Optics PD FEB 1 PY 2007 VL 46 IS 4 BP 483 EP 488 DI 10.1364/AO.46.000483 PG 6 WC Optics SC Optics GA 130EO UT WOS:000243782500005 PM 17230239 ER PT J AU Cockell, CS Brack, A Wynn-Williams, DD Baglioni, P Brandstatter, F Demets, R Edwards, HGM Gronstal, AL Kurat, G Lee, P Osinski, GR Pearce, DA Pillinger, JM Roten, CA Sancisi-Frey, S AF Cockell, Charles S. Brack, Andre Wynn-Williams, David D. Baglioni, Pietro Brandstaetter, Franz Demets, Rene Edwards, Howell G. M. Gronstal, Aaron L. Kurat, Gero Lee, Pascal Osinski, Gordon R. Pearce, David A. Pillinger, Judith M. Roten, Claude-Alain Sancisi-Frey, Suzy TI Interplanetary transfer of photosynthesis: An experimental demonstration of a selective dispersal filter in planetary island biogeography SO ASTROBIOLOGY LA English DT Article DE microbe-mineral interactions; spacecraft experiments; Mars; panspermia; oxygenic photosynthesis ID BACILLUS-SUBTILIS SPORES; SPACE ENVIRONMENT; ATMOSPHERIC ENTRY; DEVON ISLAND; CYANOBACTERIA; ALGAE; EARTH; MARS; CHROOCOCCIDIOPSIS; MICROORGANISMS AB We launched a cryptoendolithic habitat, made of a gneissic impactite inoculated with Chroococcidiopsis sp., into Earth orbit. After orbiting the Earth for 16 days, the rock entered the Earth's atmosphere and was recovered in Kazakhstan. The heat of entry ablated and heated the rock to a temperature well above the. upper temperature limit for life to below the depth at which light levels are insufficient for photosynthetic organisms (similar to 5 mm), thus killing all of its photosynthetic inhabitants. This experiment shows that atmospheric transit acts as a strong biogeographical dispersal filter to the interplanetary transfer of photosynthesis. Following atmospheric entry we found that a transparent, glassy fusion crust had formed on the outside of the rock. Re-inoculated Chroococcidiopsis grew preferentially under the fusion crust in the relatively unaltered gneiss beneath. Organisms under the fusion grew approximately twice as fast as the organisms on the control rock. Thus, the biologically destructive effects of atmospheric transit can generate entirely novel and improved endolithic habitats for organisms on the destination planetary body that survive the dispersal filter. The experiment advances our understanding of how island biogeography works on the interplanetary scale. C1 Open Univ, Ctr Earth Planetry Space & Astron Res, Planetry & Space Sci Res Inst, Milton Keynes MK7 6AA, Bucks, England. CNRS, Ctr Biophys Mol, F-45071 Orleans, France. British Antarctic Survey, Cambridge CB3 0ET, England. European Space Technol Ctr, NL-2200 AG Noordwijk, Netherlands. Nat Hist Museum, Vienna, Austria. Univ Bradford, Sch Life Sci, Bradford BD7 1DP, W Yorkshire, England. NASA, Ames Res Ctr, SETI Inst, Moffett Field, CA 94035 USA. Canadian Space Agcy, St Hubert, PQ, Canada. Fac Med, Inst Genet & Biol Microbiennes, Lausanne, Switzerland. RP Cockell, CS (reprint author), Open Univ, Ctr Earth Planetry Space & Astron Res, Planetry & Space Sci Res Inst, Milton Keynes MK7 6AA, Bucks, England. EM c.s.cockell@open.ac.uk NR 39 TC 29 Z9 30 U1 3 U2 11 PU MARY ANN LIEBERT INC PI NEW ROCHELLE PA 140 HUGUENOT STREET, 3RD FL, NEW ROCHELLE, NY 10801 USA SN 1531-1074 J9 ASTROBIOLOGY JI Astrobiology PD FEB PY 2007 VL 7 IS 1 BP 1 EP 9 DI 10.1089/ast.2006.0038 PG 9 WC Astronomy & Astrophysics; Biology; Geosciences, Multidisciplinary SC Astronomy & Astrophysics; Life Sciences & Biomedicine - Other Topics; Geology GA 157MT UT WOS:000245724900001 PM 17407400 ER PT J AU Tarter, JC Backus, PR Mancinelli, RL Aurnou, JM Backman, DE Basri, GS Boss, AP Clarke, A Deming, D Doyle, LR Feigelson, ED Freund, F Grinspoon, DH Haberle, RM Hauck, SA Heath, MJ Henry, TJ Hollingsworth, JL Joshi, MM Kilston, S Liu, MC Meikle, E Reid, IN Rothschild, LJ Scalo, J Segura, A Tang, CM Tiedje, JM Turnbull, MC Walkowicz, LM Weber, AL Young, RE AF Tarter, Jill C. Backus, Peter R. Mancinelli, Rocco L. Aurnou, Jonathan M. Backman, Dana E. Basri, Gibor S. Boss, Alan P. Clarke, Andrew Deming, Drake Doyle, Laurance R. Feigelson, Eric D. Freund, Friedmann Grinspoon, David H. Haberle, Robert M. Hauck, Steven A., II Heath, Martin J. Henry, Todd J. Hollingsworth, Jeffery L. Joshi, Manoj M. Kilston, Steven Liu, Michael C. Meikle, Eric Reid, I. Neill Rothschild, Lynn J. Scalo, John Segura, Antigona Tang, Carol M. Tiedje, James M. Turnbull, Margaret C. Walkowicz, Lucianne M. Weber, Arthur L. Young, Richard E. TI A reappraisal of the habitability of planets around M dwarf stars SO ASTROBIOLOGY LA English DT Review DE planets; habitability; M dwarfs; stars ID LOW-MASS STARS; MAIN-SEQUENCE STARS; EARTH-LIKE PLANETS; DIFFUSE INTERSTELLAR-MEDIUM; DIGITAL SKY SURVEY; TERRESTRIAL PLANETS; COOL NEIGHBORS; BROWN DWARFS; NEARBY-STAR; SPECTROSCOPIC SURVEY AB Stable, hydrogen-burning, M dwarf stars make up about 75% of all stars in the Galaxy. They are extremely long-lived, and because they are much smaller in mass than the Sun (between 0.5 and 0.08 M-sun), their temperature and stellar luminosity are low and peaked in the red. We have re-examined what is known at present about the potential for a terrestrial planet forming within, or migrating into, the classic liquid-surface-water habitable zone close to an M dwarf star. Observations of protoplanetary disks suggest that planet-building materials are common around M dwarfs, but N-body simulations differ in their estimations of the likelihood of potentially habitable, wet planets that reside within their habitable zones, which are only about one-fifth to 1/50(th) of the width of that for a G star. Particularly in light of the claimed detection of the planets with masses as small as 5.5 and 7.5 M-Earth orbiting M stars, there seems no reason to exclude the possibility of terrestrial planets. Tidally locked synchronous rotation within the narrow habitable zone does not necessarily lead to atmospheric collapse, and active stellar flaring may not be as much of an evolutionarily disadvantageous factor as has previously been supposed. We conclude that M dwarf stars may indeed be viable hosts for planets on which the origin and evolution of life can occur. A number of planetary processes such as cessation of geother mal activity or thermal and nonthermal atmospheric loss processes may limit the duration of planetary habitability to periods far shorter than the extreme lifetime of the M dwarf star. Nevertheless, it makes sense to include M dwarf stars in programs that seek to find habitable worlds and evidence of life. This paper presents the summary conclusions of an interdisciplinary workshop (http://mstars.seti.org) sponsored by the NASA Astrobiology Institute and convened at the SETI Institute. C1 SETI Inst, Mountain View, CA 94043 USA. Univ Calif Los Angeles, Los Angeles, CA USA. Univ Calif Berkeley, Berkeley, CA 94720 USA. Carnegie Inst Sci, Washington, DC 20005 USA. British Antarctic Survey, Cambridge CB3 0ET, England. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Penn State Univ, University Pk, PA 16802 USA. SW Res Inst, Boulder, CO USA. Ball Aerosp & Technol Corp, Boulder, CO USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Case Western Reserve Univ, Cleveland, OH 44106 USA. Ecospheres Project, Greenwich, England. Georgia State Univ, Atlanta, GA 30303 USA. UK Meteorol Off, Reading, Berks, England. Univ Hawaii, Honolulu, HI 96822 USA. Natl Ctr Sci Educ, Oakland, CA USA. Space Telescope Sci Inst, Baltimore, MD 21218 USA. Univ Texas, Austin, TX 78712 USA. CALTECH, Pasadena, CA 91125 USA. Calif Acad Sci, San Francisco, CA 94118 USA. Michigan State Univ, E Lansing, MI 48824 USA. Univ Washington, Seattle, WA 98195 USA. RP Tarter, JC (reprint author), SETI Inst, 515 N Whisman Rd, Mountain View, CA 94043 USA. EM tarter@seti.org RI Hauck, Steven/A-7865-2008; Joshi, Manoj/C-1795-2008; Piper, Walter/B-7908-2009; Mancinelli, Rocco/L-8971-2016 OI Hauck, Steven/0000-0001-8245-146X; Joshi, Manoj/0000-0002-2948-2811; NR 225 TC 154 Z9 156 U1 6 U2 41 PU MARY ANN LIEBERT, INC PI NEW ROCHELLE PA 140 HUGUENOT STREET, 3RD FL, NEW ROCHELLE, NY 10801 USA SN 1531-1074 EI 1557-8070 J9 ASTROBIOLOGY JI Astrobiology PD FEB PY 2007 VL 7 IS 1 BP 30 EP 65 DI 10.1089/ast.2006.0124 PG 36 WC Astronomy & Astrophysics; Biology; Geosciences, Multidisciplinary SC Astronomy & Astrophysics; Life Sciences & Biomedicine - Other Topics; Geology GA 157MT UT WOS:000245724900004 PM 17407403 ER PT J AU Scalo, J Kaltenegger, L Segura, AG Fridlund, M Ribas, I Kulikov, YN Grenfell, JL Rauer, H Odert, P Leitzinger, M Selsis, F Khodachenko, ML Eiroa, C Kasting, J Lammer, H AF Scalo, John Kaltenegger, Lisa Segura, Ant Gona Fridlund, Malcolm Ribas, Ignasi Kulikov, Yu. N. Grenfell, John L. Rauer, Heike Odert, Petra Leitzinger, Martin Selsis, F. Khodachenko, Maxim L. Eiroa, Carlos Kasting, Jim Lammer, Helmut TI M stars as targets for terrestrial exoplanet searches and biosignature detection SO ASTROBIOLOGY LA English DT Review DE M star planets; habitable planets; life and stellar activity; spectral biosignatures; terrestrial planet formation; exoplanet properties ID EARTH-LIKE PLANETS; SOLAR-TYPE STARS; MAIN-SEQUENCE STARS; LOW-MASS STARS; X-RAY-EMISSION; CARBON-DIOXIDE CLOUDS; SUN-LIKE STARS; CYCLOBUTANE PYRIMIDINE DIMERS; EXTRASOLAR GIANT PLANETS; HOBBY-EBERLY TELESCOPE AB The changing view of planets orbiting low mass stars, M stars, as potentially hospitable worlds for life and its remote detection was motivated by several factors, including the demonstration of viable atmospheres and oceans on tidally locked planets, normal incidence of dust disks, including debris disks, detection of planets with masses in the 5-20 M-circle plus range, and predictions of unusually strong spectral biosignatures. We present a critical discussion of M star properties that are relevant for the long- and short-term thermal, dynamical, geological, and environmental stability of conventional liquid water habitable zone (HZ) M star planets, and the advantages and disadvantages of M stars as targets in searches for terrestrial HZ planets using various detection techniques. Biological viability seems supported by unmatched very long-term stability conferred by tidal locking, small HZ size, an apparent shortfall of gas giant planet perturbers, immunity to large astrosphere compressions, and several other factors, assuming incidence and evolutionary rate of life benefit from lack of variability. Tectonic regulation of climate and dynamo generation of a protective magnetic field, especially for a planet in synchronous rotation, are important unresolved questions that must await improved geodynamic models, though they both probably impose constraints on the planet mass. M star HZ terrestrial planets must survive a number of early trials in order to enjoy their many Gyr of stability. Their formation may be jeopardized by an insufficient initial disk supply of solids, resulting in the formation of objects too small and/or dry for habitability. The small empirical gas giant fraction for M stars reduces the risk of formation suppression or orbit disruption from either migrating or nonmigrating giant planets, but effects of perturbations from lower mass planets in these systems are uncertain. During the first similar to 1 Gyr, atmospheric retention is at peril because of intense and frequent stellar flares and sporadic energetic particle events, and impact erosion, both enhanced, the former dramatically, for M star HZ semimajor axes. Loss of atmosphere by interactions with energetic particles is likely unless the planetary magnetic moment is sufficiently large. For the smallest stellar masses a period of high planetary surface temperature, while the parent star approaches the main sequence, must be endured. The formation and retention of a thick atmosphere and a strong magnetic field as buffers for a sufficiently massive planet emerge as prerequisites for an M star planet to enter a long period of stability with its habitability intact. However, the star will then be subjected to short-term fluctuations with consequences including frequent unpredictable variation in atmospheric chemistry and surficial radiation field. After a review of evidence concerning disks and planets associated with M stars, we evaluate M stars as targets for future HZ planet search programs. Strong advantages of M stars for most approaches to HZ detection are offset by their faintness, leading to severe constraints due to accessible sample size, stellar crowding (transits), or angular size of the HZ (direct imaging). Gravitational lensing is unlikely to detect HZ M star planets because the HZ size decreases with mass faster than the Einstein ring size to which the method is sensitive. M star Earth-twin planets are predicted to exhibit surprisingly strong bands of nitrous oxide, methyl chloride, and methane, and work on signatures for other climate categories issummarized. The rest of the paper is devoted to an examination of evidence and implications of the unusual radiation and particle environments for atmospheric chemistry and surface radiation doses, and is summarized in the Synopsis. We conclude that attempts at remote sensing of biosignatures and nonbiological markers from M star planets are important, not as tests of any quantitative theories or rational arguments, but instead because they offer an inspection of the residues from a Gyr-long biochemistry experiment in the presence of extreme environmental fluctuations. A detection or repeated nondetections could provide a unique opportunity to partially answer a fundamental and recurrent question about the relation between stability and complexity, one that is not addressed by remote detection from a planet orbiting a solar-like star, and can only be studied on Earth using restricted microbial systems in serial evolution experiments or in artificial life simulations. This proposal requires a planet that has retained its atmosphere and a water supply. The discussion given here suggests that observations of M star exoplanets can decide this latter question with only slight modifications to plans already in place for direct imaging terrestrial exoplanet missions. C1 Univ Texas, Dept Astron, Austin, TX 78712 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. CALTECH, Jet Prop Lab, Pasadena, CA USA. European Space Agcy, Estec, NL-2200 AG Noordwijk, Netherlands. Inst Estudis Especials Catalunya, Barcelona, Spain. Inst Ciencias Espaciais, Barcelona, Spain. Russian Acad Sci, Polar Geophys Inst, Murmansk, Russia. Inst Planet Forsch Extrasolare Planet & Atmosphar, Berlin, Germany. Graz Univ, Inst Phys, Graz, Austria. Austrian Acad Sci, Space Res Inst, A-8010 Graz, Austria. Ctr Rech Astrophys Lyon, Lyon, France. Ecole Normale Super, Lyon, France. Univ Autonoma Madrid, Fac Ciencias, Dept Fis Teor, E-28049 Madrid, Spain. Penn State Univ, Dept Geosci, State Coll, PA USA. RP Scalo, J (reprint author), Univ Texas, Dept Astron, RLM 15308, Austin, TX 78712 USA. EM parrot@astro.as.utexas.edu RI Ribas, Ignasi/M-2134-2014; Kulikov, Yuri/B-7866-2017; Kulikov, Yuri/H-7799-2013 OI Ribas, Ignasi/0000-0002-6689-0312; Kulikov, Yuri/0000-0002-1741-3907; Kulikov, Yuri/0000-0001-5475-3284 NR 427 TC 155 Z9 157 U1 6 U2 80 PU MARY ANN LIEBERT, INC PI NEW ROCHELLE PA 140 HUGUENOT STREET, 3RD FL, NEW ROCHELLE, NY 10801 USA SN 1531-1074 EI 1557-8070 J9 ASTROBIOLOGY JI Astrobiology PD FEB PY 2007 VL 7 IS 1 BP 85 EP 166 DI 10.1089/ast.2006.0000 PG 82 WC Astronomy & Astrophysics; Biology; Geosciences, Multidisciplinary SC Astronomy & Astrophysics; Life Sciences & Biomedicine - Other Topics; Geology GA 157MT UT WOS:000245724900006 PM 17407405 ER PT J AU Kiang, NY Siefert, J Govindjee Blankenship, RE AF Kiang, Nancy Y. Siefert, Janet Govindjee Blankenship, Robert E. TI Spectral signatures of photosynthesis. I. Review of Earth organisms SO ASTROBIOLOGY LA English DT Review DE photosynthesis; photosynthetic pigments; leaf spectral reflectance; oxygenic photosynthesis; anoxygenic photosynthesis; atmospheric radiative transfer; chlorophyll; bacteriochlorophyll; red edge; radiation spectrum; photosynthetically active radiation; light harvesting; review; Virtual Planetary Laboratory ID ELECTRON-TRANSFER REACTIONS; NIVALIS BAUER WILLE; REACTION CENTERS; PURPLE BACTERIA; CHLOROPHYLL-D; OXYGENIC PHOTOSYNTHESIS; ULTRAVIOLET-RADIATION; PHOTOSYSTEM-II; VOLUME CHANGE; PRIMARY PRODUCTIVITY AB Why do plants reflect in the green and have a "red edge" in the red, and should extrasolar photosynthesis be the same? We provide (1) a brief review of how photosynthesis works, (2) an overview of the diversity of photosynthetic organisms, their light harvesting systems, and environmental ranges, (3) a synthesis of photosynthetic surface spectral signatures, and (4) evolutionary rationales for photosynthetic surface reflectance spectra with regard to utilization of photon energy and the planetary light environment. We found the "near-infrared (NIR) end" of the red edge to trend from blue-shifted to reddest for (in order) snow algae, temperate algae, lichens, mosses, aquatic plants, and finally terrestrial vascular plants. The red edge is weak or sloping in lichens. Purple bacteria exhibit possibly a sloping edge in the NIR. More studies are needed on pigment-protein complexes, membrane composition, and measurements of bacteria before firm conclusions can be drawn about the role of the NIR reflectance. Pigment absorbance features are strongly correlated with features of atmospheric spectral transmittance: P680 in Photosystem H with the peak surface incident photon flux density at similar to 685 nm, just before an oxygen band at 687.5 nm; the NIR end of the red edge with water absorbance bands and the oxygen A-band at 761 nm; and bacteriochlorophyll reaction center wavelengths with local maxima in atmospheric and water transmittance spectra. Given the surface incident photon flux density spectrum and resonance transfer in light harvesting, we propose some rules with regard to where photosynthetic pigments will peak in absorbance: (1) the wavelength of peak incident photon flux; (2) the longest available wavelength for core antenna or reaction center pigments; and (3) the shortest wavelengths within an atmospheric window for accessory pigments. That plants absorb less green light may not be an inefficient legacy of evolutionary history, but may actually satisfy the above criteria. C1 NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Rice Univ, Dept Stat, Houston, TX 77251 USA. Univ Illinois, Dept Plant Biol, Urbana, IL 61801 USA. Univ Illinois, Dept Biochem, Urbana, IL 61801 USA. Washington Univ, Dept Biol & Chem, St Louis, MO USA. RP Kiang, NY (reprint author), NASA, Goddard Inst Space Studies, New York, NY 10025 USA. EM nkiang@giss.nasa.gov NR 140 TC 95 Z9 101 U1 21 U2 156 PU MARY ANN LIEBERT INC PI NEW ROCHELLE PA 140 HUGUENOT STREET, 3RD FL, NEW ROCHELLE, NY 10801 USA SN 1531-1074 J9 ASTROBIOLOGY JI Astrobiology PD FEB PY 2007 VL 7 IS 1 BP 222 EP 251 DI 10.1089/ast.2006.0105 PG 30 WC Astronomy & Astrophysics; Biology; Geosciences, Multidisciplinary SC Astronomy & Astrophysics; Life Sciences & Biomedicine - Other Topics; Geology GA 157MT UT WOS:000245724900010 PM 17407409 ER PT J AU Kiang, NY Segura, A Tinetti, G Govindjee Blankenship, RE Cohen, M Siefert, J Crisp, D Meadows, VS AF Kiang, Nancy Y. Segura, Antigona Tinetti, Giovanna Govindjee Blankenship, Robert E. Cohen, Martin Siefert, Janet Crisp, David Meadows, Victoria S. TI Spectral signatures of photosynthesis. II. Coevolution with other stars and the atmosphere on extrasolar worlds SO ASTROBIOLOGY LA English DT Article DE photosynthesis; astrobiology; photosynthetic pigments; oxygenic photosynthesis; anoxygenic photosynthesis; atmospheric photochemistry; F stars; G stars; Sun; K stars; M stars; AD Leo; atmospheric oxygen; atmospheric radiative transfer; chlorophyll; bacteriochlorophyll; photosystems; radiation spectrum; photosynthetically active radiation; light harvesting; modeling; extrasolar planets; Earth-like planets; Virtual Planetary Laboratory; biosignatures ID EARTH-LIKE PLANETS; DISK-AVERAGED SPECTRA; NEPTUNE-MASS PLANET; TERRESTRIAL PLANETS; HYDROTHERMAL VENTS; KEPLER MISSION; AD LEONIS; RED-EDGE; M-DWARFS; WATER AB As photosynthesis on Earth produces the primary signatures of life that can be detected astronomically at the global scale, a strong focus of the search for extrasolar life will be photosynthesis, particularly photosynthesis that has evolved with a different parent star. We take previously simulated planetary atmospheric compositions for Earth-like planets around observed F2V and K2V, modeled M1V and M5V stars, and around the active M4.5V star AD Leo; our scenarios use Earth's atmospheric composition as well as very low O-2 content in case anoxygenic photosynthesis dominates. With a line-by-line radiative transfer model, we calculate the incident spectral photon flux densities at the surface of the planet and under water. We identify bands of available photosynthetically relevant radiation and find that photosynthetic pigments on planets around F2V stars may peak in absorbance in the blue, K2V in the red-orange, and M stars in the near-infrared, in bands at 0.93-1.1 mu m, 1.1-1.4 mu m, 1.5-1.8 mu m, and 1.8-2.5 mu m. However, underwater organisms will be restricted to wavelengths shorter than 1.4 mu m and more likely below 1.1 mu m. M star planets without oxygenic photosynthesis will have photon fluxes above 1.6 mu m curtailed by methane. Longer-wavelength, multi-photosystem series would reduce the quantum yield but could allow for oxygenic photosystems at longer wavelengths. A wavelength of 1.1 mu m is a possible upper cutoff for electronic transitions versus only vibrational energy; however, this cutoff is not strict, since such energetics depend on molecular configuration. M star planets could be a half to a tenth as productive as Earth in the visible, but exceed Earth if useful photons extend to 1.1 mu m for anoxygenic photosynthesis. Under water, organisms would still be able to survive ultraviolet flares from young M stars and acquire adequate light for growth. C1 NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Univ Nacl Autonoma Mexico, Inst Ciencias Nucl, Mexico City 04510, DF, Mexico. European Space Agcy, Inst Astrophys Paris, Paris, France. Univ Illinois, Dept Plant Biol, Urbana, IL 61801 USA. Univ Illinois, Dept Biochem, Urbana, IL 61801 USA. Washington Univ, Dept Biol & Chem, St Louis, MO USA. Univ Calif Berkeley, Radio Astron Lab, Berkeley, CA 94720 USA. Rice Univ, Dept Stat, Houston, TX 77251 USA. NASA, Jet Propuls Lab, Pasadena, CA USA. CALTECH, Spitzer Sci Ctr, Pasadena, CA 91125 USA. RP Kiang, NY (reprint author), NASA, Goddard Inst Space Studies, New York, NY 10025 USA. EM nkiang@giss.nasa.gov OI Tinetti, Giovanna/0000-0001-6058-6654 NR 92 TC 78 Z9 82 U1 2 U2 26 PU MARY ANN LIEBERT, INC PI NEW ROCHELLE PA 140 HUGUENOT STREET, 3RD FL, NEW ROCHELLE, NY 10801 USA SN 1531-1074 EI 1557-8070 J9 ASTROBIOLOGY JI Astrobiology PD FEB PY 2007 VL 7 IS 1 BP 252 EP 274 DI 10.1089/ast.2006.0108 PG 23 WC Astronomy & Astrophysics; Biology; Geosciences, Multidisciplinary SC Astronomy & Astrophysics; Life Sciences & Biomedicine - Other Topics; Geology GA 157MT UT WOS:000245724900011 PM 17407410 ER PT J AU Olkin, CB Young, EF Young, LA Grundy, W Schmitt, B Tokunaga, A Owen, T Roush, T Terada, H AF Olkin, C. B. Young, E. F. Young, L. A. Grundy, W. Schmitt, B. Tokunaga, A. Owen, T. Roush, T. Terada, H. TI Pluto's spectrum from 1.0 to 4.2 mu m: Implications for surface properties SO ASTRONOMICAL JOURNAL LA English DT Article DE planets and satellites : individual (Pluto) ID H2O ICE; X-RAY; TEMPERATURE; METHANE; TRITON; ATMOSPHERE; HYDROCARBONS; SPECTROSCOPY; SPECTROGRAPH; ABSORPTION AB We present spectra of Pluto's anti-Charon hemisphere obtained from the Keck and Subaru telescopes from 2.8 to 4.2 mu m. Combined with 1-2.5 mu m spectra from the Infrared Telescope Facility, this collective data set lets us constrain several surface frost properties. The surface area of pure nitrogen frost ( as opposed to nitrogen with dissolved methane) is constrained to be 6% or less. The areal fractions of pure methane and methane dissolved in nitrogen are almost equal. The grain size of pure methane is constrained to be near 200 mu m. An additional surface component with spectral properties similar to Titan tholin was necessary to fit the entire 1-4.2 mu m spectrum; our best-fit model requires 21% of Pluto's anti-Charon hemisphere (by area) to be this Titan tholin component. Contrary to Sasaki et al.'s spectra of Pluto's sub-Charon hemisphere, we find no evidence for other hydrocarbons on this face of Pluto from data in the 3-3.3 mu m region. We were not able to constrain the temperature of pure methane. C1 SW Res Inst, Dept Space Studies, Boulder, CO USA. Lowell Observ, Flagstaff, AZ 86001 USA. Univ Grenoble 1, CNRS, Lab Planetol Grenoble, Grenoble, France. Univ Hawaii, Inst Astron, Honolulu, HI 96822 USA. NASA, Ames Res Ctr, Moffett Field, CA USA. Natl Astron Observ, Subaru Telescope, Hilo, HI USA. RP Olkin, CB (reprint author), SW Res Inst, Dept Space Studies, Boulder, CO USA. EM colkin@boulder.swri.edu RI Schmitt, Bernard/A-1064-2009 OI Schmitt, Bernard/0000-0002-1230-6627 NR 33 TC 33 Z9 33 U1 1 U2 5 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-6256 J9 ASTRON J JI Astron. J. PD FEB PY 2007 VL 133 IS 2 BP 420 EP 431 DI 10.1086/509616 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 129LC UT WOS:000243730000007 ER PT J AU Ganguly, R Brotherton, MS Arav, N Heap, SR Wisotzki, L Aldcroft, TL Alloin, D Behar, E Canalizo, G Crenshaw, DM De Kool, M Chambers, K Cecil, G Chatzichristou, E Everett, J Gabel, J Gaskell, CM Galliano, E Green, RF Hall, PB Hines, DC Junkkarinen, VT Kaastra, JS Kaiser, ME Kazanas, D Konigl, A Korista, KT Kriss, GA Laor, A Leighly, KM Mathur, S Ogle, P Proga, D Sabra, B Sivron, R Snedden, S Telfer, R Vestergaard, M AF Ganguly, Rajib Brotherton, Michael S. Arav, Nahum Heap, Sara R. Wisotzki, Lutz Aldcroft, Thomas L. Alloin, Danielle Behar, Ehud Canalizo, Gabriela Crenshaw, D. Michael De Kool, Martijn Chambers, Kenneth Cecil, Gerald Chatzichristou, Eleni Everett, John Gabel, Jack Gaskell, C. Martin Galliano, Emmanuel Green, Richard F. Hall, Patrick B. Hines, Dean C. Junkkarinen, Vesa T. Kaastra, Jelle S. Kaiser, Mary Elizabeth Kazanas, Demosthenes Konigl, Arieh Korista, Kirk T. Kriss, Gerard A. Laor, Ari Leighly, Karen M. Mathur, Smita Ogle, Patrick Proga, Daniel Sabra, Bassem Sivron, Ran Snedden, Stephanie Telfer, Randal Vestergaard, Marianne TI Hubble Space Telescope ultraviolet spectroscopy of 14 low-redshift quasars SO ASTRONOMICAL JOURNAL LA English DT Article DE quasars : absorption lines; quasars : emission lines; surveys ID BROAD ABSORPTION-LINE; ACTIVE GALACTIC NUCLEI; C-IV LAMBDA-1549; RADIATION-DRIVEN WINDS; RADIO-QUIET QUASARS; DIGITAL SKY SURVEY; STELLAR OBJECTS; EMISSION-LINE; INTRINSIC ABSORPTION; IMAGING SPECTROGRAPH AB We present low-resolution ultraviolet spectra of 14 low-redshift (z(em) less than or similar to 0.8) quasars observed with the Hubble Space Telescope STIS as part of a Snapshot project to understand the relationship between quasar outflows and luminosity. By design, all observations cover the C (IV) emission line. Ten of the quasars are from the Hamburg-ESO catalog, three are from the Palomar-Green catalog, and one is from the Parkes catalog. The sample contains a few interesting quasars, including two broad absorption line (BAL) quasars (HE 0143 - 3535 and HE 0436 - 2614), one quasar with a mini-BAL (HE 1105 - 0746), and one quasar with associated narrow absorption (HE 0409 - 5004). These BAL quasars are among the brightest known (although not the most luminous) since they lie at z(em) < 0.8. We compare the properties of these BAL quasars to the z(em) < 0.5 Palomar-Green and z(em) > 1.4 Large Bright Quasar Survey samples. By design, our objects sample luminosities in between these two surveys, and our four absorbed objects are consistent with the v similar to L-0.62 relation derived by Laor & Brandt (2002). Another quasar, HE 0441 - 2826, contains extremely weak emission lines, and our spectrum is consistent with a simple power-law continuum. The quasar is radio-loud but has a steep spectral index and a lobe-dominated morphology, which argues against it being ablazar. The unusual spectrum of this quasar resembles the spectra of the quasars PG 1407 + 265, SDSS J1136 + 0242, and PKS 1004 + 13, for which several possible explanations have been entertained. C1 Univ Wyoming, Dept Phys & Astron, Laramie, WY 82071 USA. Univ Colorado, Ctr Astrophys & Space Astron, Boulder, CO 80309 USA. NASA, Goddard Space Flight Ctr, Lab Astron & Solar Phys, Greenbelt, MD 20771 USA. Astrophys Inst Potsdam, Potsdam, Germany. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. European So Observ, Santiago 19, Chile. Univ Paris 07, UMR 7158, CEA Saclay, DSM,DAPNIA,Serv Astrophys,CNRS, Paris, France. Technion, Dept Phys, Haifa, Israel. Univ Calif Riverside, Dept Phys, Riverside, CA 92521 USA. Georgia State Univ, Dept Phys & Astron, Atlanta, GA 30303 USA. Mt Stromlo & Siding Spring Observ, Res Sch Astron & Astrophys, Weston, ACT, Australia. Inst Astron, Honolulu, HI USA. Univ N Carolina, Dept Phys & Astron, Chapel Hill, NC USA. Natl Observ Athens, Inst Astron & Astrophys, Athens, Greece. Univ Toronto, Canadian Inst Theoret Astrophys, Toronto, ON, Canada. Univ Wisconsin, Dept Astron, Dept Phys, Madison, WI USA. Univ Wisconsin, Ctr Magnet Self Org, Madison, WI USA. Univ Nebraska, Dept Phys & Astron, Lincoln, NE 68588 USA. Univ Calif Davis, Dept Phys, Davis, CA 95616 USA. Large Binocular Telescope Observ, Tucson, AZ USA. York Univ, Dept Phys & Astron, Toronto, ON M3J 2R7, Canada. Space Sci Inst, Boulder, CO USA. Univ Calif San Diego, Ctr Astrophys & Space Sci, San Diego, CA 92103 USA. SRON Netherlands Inst Space Res, Utrecht, Netherlands. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. Univ Chicago, Dept Astron & Astrophys, Chicago, IL 60637 USA. Univ Chicago, Enrico Fermi Inst, Chicago, IL 60637 USA. Western Michigan Univ, Dept Phys, Kalamazoo, MI 49008 USA. Space Telescope Sci Inst, Baltimore, MD 21218 USA. Univ Oklahoma, Homer L Dodge Dept Phys & Astron, Norman, OK 73019 USA. Ohio State Univ, Dept Astron, Columbus, OH 43210 USA. CALTECH, Spitzer Sci Ctr, Pasadena, CA 91125 USA. Univ Nevada, Dept Phys, Las Vegas, NV 89154 USA. Univ Notre Dame, Fac Nat & Appl Sci, Zouk Mosbeh, Lebanon. Baker Univ, Dept Phys, Baldwin City, KS USA. Apache Point Observ, Sunspot, NM USA. Orbital Sci Corp, Greenbelt, MD USA. Univ Arizona, Steward Observ, Tucson, AZ USA. RP Ganguly, R (reprint author), Univ Wyoming, Dept Phys & Astron, Laramie, WY 82071 USA. EM ganguly@uwyo.edu RI heap, sara/E-2237-2012; Vestergaard, Marianne/M-5247-2014; OI Vestergaard, Marianne/0000-0001-9191-9837; Gaskell, C/0000-0003-4888-2009; Chambers, Kenneth /0000-0001-6965-7789 NR 52 TC 5 Z9 5 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-6256 J9 ASTRON J JI Astron. J. PD FEB PY 2007 VL 133 IS 2 BP 479 EP 486 DI 10.1086/510129 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 129LC UT WOS:000243730000011 ER PT J AU Aspin, C Greene, TP AF Aspin, Colin Greene, Thomas P. TI High spectral resolution near-IR observations of ESO-H alpha 279A and 279B SO ASTRONOMICAL JOURNAL LA English DT Article DE circumstellar matter; stars : activity; stars : formation; stars : pre-main-sequence ID YOUNG STELLAR OBJECTS; INFRARED CO EMISSION; HARO ENERGY-SOURCES; STARS; DISK; BINARY; PHOTOSPHERES; SPECTROSCOPY; PROTOSTARS; DISCOVERY AB We present high spectral resolution near-IR observations of the stars ESO-H alpha 279A and 279B located in the Serpens star formation complex. ESO-H alpha 279A is a known young T Tauri star driving a Herbig-Haro flow, while ESO-H alpha 279B is a nearby (8", 2500 AU) extremely red companion. Previous work has suggested that this is not a physically bound system but a chance alignment of a young star and a background giant. Below, we further investigate the nature of ESO-H alpha 279B and probe the emission characteristics of ESO-H alpha 279A. We find that ESO-H alpha 279B shows many narrow absorption features typical of late-type giant stars and unlike those seen in FU Orionis objects and Herbig-Haro energy sources, the only young stars that exhibit such deep CO absorption. This result confirms that ESO-H alpha 279B is a background M-type giant viewed through the molecular cloud hosting ESO-H alpha 279A, and therefore, the association of ESO-H alpha 279A and 279B is fortuitous. For ESO-H alpha 279A we find that the Na doublet lines are broadened and self-absorbed and that the v = 2-0 CO overtone and head is similar in shape to that observed in the young pre-main-sequence object SVS 13 in NGC 1333, and not characteristic of a rotating-disk velocity dispersion. We consider the origin of the CO emission in relation to current models and suggest that it perhaps is more indicative of creation in a wind or funnel flow rather than in the inner hot regions of a circumstellar disk. C1 Univ Hawaii, Inst Astron, Honolulu, HI 96822 USA. Gemini Observ, Hilo, HI USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Aspin, C (reprint author), Univ Hawaii, Inst Astron, 2680 Woodlawn Dr, Honolulu, HI 96822 USA. EM caa@gemini.edu; tgreene@mail.arc.nasa.gov NR 42 TC 2 Z9 2 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-6256 J9 ASTRON J JI Astron. J. PD FEB PY 2007 VL 133 IS 2 BP 568 EP 575 DI 10.1086/510133 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 129LC UT WOS:000243730000022 ER PT J AU Miller, L Turner, TJ Reeves, JN George, IM Kraemer, SB Wingert, B AF Miller, L. Turner, T. J. Reeves, J. N. George, I. M. Kraemer, S. B. Wingert, B. TI The variable X-ray spectrum of Markarian 766 - I. Principal components analysis SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE galaxies : Seyfert; X-rays : individuals : Mrk 766; accretion; accretion disks; galaxies : active; X-rays : galaxies ID ACTIVE GALACTIC NUCLEI; ACCRETING BLACK-HOLES; LINE SEYFERT-1 GALAXIES; XMM-NEWTON; COMPTON REFLECTION; ASCA OBSERVATIONS; IONIZED OUTFLOW; COLD MATTER; ALPHA LINE; IRON AB Aims. We analyse a long XMM-Newton observation of the narrow-line Seyfert 1 galaxy Mrk 766, using the marked spectral variability on timescales > 20 ks to separate components in the X-ray spectrum. Methods. Principal components analysis is used to identify distinct emission components in the X-ray spectrum, possible alternative physical models for those components are then compared statistically. Results. The source spectral variability is well-explained by additive variations, with smaller extra contributions most likely arising from variable absorption. The principal varying component, eigenvector one, is found to have a steep (photon index 2.4) power-law shape, affected by a low column of ionised absorption that leads to the appearance of a soft excess. Eigenvector one varies by a factor 10 in amplitude on time-scales of days and appears to have broad ionised Fe K alpha emission associated with it: the width of the ionised line is consistent with an origin at similar to 100 gravitational radii. There is also a strong component of near-constant emission that dominates in the low state, whose spectrum is extremely hard above 1 keV, with a soft excess at lower energies, and with a strong edge at Fe K but remarkably little Fe K alpha emission. Although this component may be explained as relativistically-blurred reflection from the inner accretion disc, we suggest that its spectrum and lack of variability may alternatively be explained as either (i) ionised reflection from an extended region, possibly a disc wind, or (ii) a signature of absorption by a disc wind with a variable covering fraction. Absorption features in the low state may indicate the presence of an outflow. C1 Univ Oxford, Dept Phys, Oxford OX1 3RH, England. Univ Maryland, Dept Phys, Baltimore, MD 21250 USA. NASA, Goddard Space Flight Ctr, Xray Astrophys Lab, Astrophys Sci Div, Greenbelt, MD 20771 USA. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. Catholic Univ Amer, Washington, DC 20064 USA. RP Miller, L (reprint author), Univ Oxford, Dept Phys, Denys Wilkinson Bldg,Keble Rd, Oxford OX1 3RH, England. EM L.Miller1@physics.ox.ac.uk NR 55 TC 70 Z9 70 U1 0 U2 0 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD FEB PY 2007 VL 463 IS 1 BP 131 EP 143 DI 10.1051/0004-6361:20066548 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 132KO UT WOS:000243941900011 ER PT J AU Lopez-Santiago, J Micela, G Sciortino, S Favata, F Caccianiga, A Della Ceca, R Severgnini, P Braito, V AF Lopez-Santiago, J. Micela, G. Sciortino, S. Favata, F. Caccianiga, A. Della Ceca, R. Severgnini, P. Braito, V. TI The stellar content of the XMM-Newton bright serendipitous survey SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE galaxy : stellar content; stars : activity; stars : coronae; stars : formation; stars : magnetic fields; X-rays : stars ID X-RAY-EMISSION; EINSTEIN-OBSERVATORY SURVEY; LATE-TYPE STARS; MEDIUM-SENSITIVITY SURVEY; INCREMENTAL DATA RELEASE; MAIN-SEQUENCE STARS; FIELD-NORTH SURVEY; LATE F-DWARF; SOLAR NEIGHBORHOOD; CORONAL COMPONENT AB Context. The comparison of observed counts in a given sky direction with predictions by Galactic models yields constraints on the spatial distribution and the stellar birthrate of young stellar populations. The XMM-Newton Bright Serendipitous Survey (XBSS) is an unbiased survey that includes a total of 58 stellar sources selected in the 0.5-4.5 keV energy band, having a limiting sensitivity of 10(-2) cnt s(-1) and covering an area of 28.10 sq deg. Aims. We present the results of analysing the stellar content of the XBSS so as to understand the recent star formation history of the Galaxy in the vicinity of the Sun. Methods. We compared the observations with the predictions obtained with XCOUNT, a model of the stellar X-ray content of the Galaxy. The model predicts the number and properties of the stars to be observed in terms of magnitude, colour, population and f(x)/f(v) ratio distributions of the coronal sources detected with a given instrument and sensitivity in a specific sky direction. Results. As in other shallow surveys, we observe an excess of stars not predicted by our Galaxy model. Comparing the colours of the identified infrared counterparts with the model predictions, we observe that this excess is produced by yellow (G+K) stars. The study of the X-ray spectrum of each source reveals a main population of stars with the coronal temperature stratification typical of intermediate-age stars. As no assumptions have been made for the selection of the sample, our results must be representative of the entire solar neighbourhood. Some stars show infrared excess due to circumstellar absorption, which is indicative of youth. C1 Osservatorio Astron Palermo Giuseppe S Vaiana, INAF, I-90134 Palermo, Italy. European Space Agcy, European Space Res & Technol Ctr, Astrophys Miss Div, Res & Sci Support Dept, NL-2200 AG Noordwijk, Netherlands. Osserv Astron Brera, INAF, I-20121 Milan, Italy. NASA, Goddard Space Flight Ctr, Xray Astrophys Lab, Greenbelt, MD 20771 USA. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. RP Lopez-Santiago, J (reprint author), Osservatorio Astron Palermo Giuseppe S Vaiana, INAF, Piazza Parlamento 1, I-90134 Palermo, Italy. EM jlopez@astropa.unipa.it OI Severgnini, Paola/0000-0001-5619-5896; Della Ceca, Roberto/0000-0001-7551-2252; Caccianiga, Alessandro/0000-0002-2339-8264; Micela, Giuseppina/0000-0002-9900-4751; Braito, Valentina/0000-0002-2629-4989 NR 60 TC 27 Z9 27 U1 0 U2 0 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD FEB PY 2007 VL 463 IS 1 BP 165 EP U17 DI 10.1051/0004-6361:20065696 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 132KO UT WOS:000243941900014 ER PT J AU Samadi, R Georgobiani, D Trampedach, R Goupil, MJ Stein, RF Nordlund, A AF Samadi, R. Georgobiani, D. Trampedach, R. Goupil, M. J. Stein, R. F. Nordlund, A. TI Excitation of solar-like oscillations across the HR diagram SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE convection; turbulence; Sun : oscillations; Hertzsprung-Russell (HR) and C-M; stars : variables : general; methods : numerical ID P-MODES; STOCHASTIC EXCITATION; TURBULENT CONVECTION; RADIAL OSCILLATIONS; CLOSURE-MODEL; AMPLITUDES; ASTEROSEISMOLOGY; STARS; CONSTRAINTS; SEISMOLOGY AB Aims. We extend semi-analytical computations of excitation rates for solar oscillation modes to those of other solar-like oscillating stars to compare them with recent observations Methods. Numerical 3D simulations of surface convective zones of several solar-type oscillating stars are used to characterize the turbulent spectra as well as to constrain the convective velocities and turbulent entropy fluctuations in the uppermost part of the convective zone of such stars. These constraints, coupled with a theoretical model for stochastic excitation, provide the rate P at which energy is injected into the p-modes by turbulent convection. These energy rates are compared with those derived directly from the 3D simulations. Results. The excitation rates obtained from the 3D simulations are systematically lower than those computed from the semi-analytical excitation model. We find that P-max, the P maximum, scales as (L/M)(s) where s is the slope of the power law and L and M are the mass and luminosity of the 1D stellar model built consistently with the associated 3D simulation. The slope is found to depend significantly on the adopted form of chi(k), the eddy time-correlation; using a Lorentzian, chi(L)(k), results in s = 2.6, whereas a Gaussian, chi(G)(k), gives s = 3.1. Finally, values of V-max, the maximum in the mode velocity, are estimated from the computed power laws for Pmax and we find that V-max increases as (L/M)(sv). Comparisons with the currently available ground-based observations show that the computations assuming a Lorentzian chi(k) yield a slope, sv, closer to the observed one than the slope obtained when assuming a Gaussian. We show that the spatial resolution of the 3D simulations must be high enough to obtain accurate computed energy rates. C1 Observ Astron UC, Coimbra, Portugal. CNRS, Observ Paris, CNRS, UMR 8109, F-92195 Meudon, France. Stanford Univ, NASA Ames Res Ctr, Ctr Turbulence, Moffett Field, CA USA. Mt Stromlo & Siding Spring Observ, Res Sch Astron & Astrophys, Weston, ACT 2611, Australia. Michigan State Univ, Dept Phys & Astron, Lansing, MI USA. Niels Bohr Inst Astron Phys & Geophys, Copenhagen, Denmark. RP Samadi, R (reprint author), Observ Astron UC, Coimbra, Portugal. EM Reza.Samadi@obspm.fr RI Nordlund, Aake/M-4528-2014 OI Nordlund, Aake/0000-0002-2219-0541 NR 43 TC 73 Z9 73 U1 0 U2 2 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD FEB PY 2007 VL 463 IS 1 BP 297 EP 308 DI 10.1051/0004-6361:20041953 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 132KO UT WOS:000243941900028 ER PT J AU Lang, J Brooks, DH Lanzafame, AC Martin, R Pike, CD Thompson, WT AF Lang, J. Brooks, D. H. Lanzafame, A. C. Martin, R. Pike, C. D. Thompson, W. T. TI The in-flight monitoring and validation of the SOHOCDS Normal Incidence Spectrometer radiometric calibration SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE Sun : atmosphere; Sun : corona; Sun : UV radiation; atomic data; techniques : spectroscopic ID ELECTRON-IMPACT EXCITATION; SPECTRAL-LINE INTENSITIES; CORONAL DIAGNOSTIC SPECTROMETER; EXTREME-ULTRAVIOLET SPECTRUM; FINE-STRUCTURE TRANSITIONS; EMISSION MEASURE STRUCTURE; ACTIVE-REGION SPECTRUM; INNER SOLAR CORONA; BORON-LIKE IONS; ATOMIC DATA AB The scientific return from an extreme-ultraviolet spectrometer depends on the accuracy and precision of its radiometric calibration. For the Coronal Diagnostic Spectrometer on SOHO, radiometric calibration started pre-launch in the laboratory and continued after launch by making comparison measurements of the same area of the Sun with calibrated sounding rocket payloads and also by intercalibration with the SUMER instrument on SOHO. The present work uses the measurement of line ratios to monitor and validate the calibration over the first six years of observation. As well as using branching ratios and line ratios independent of the electron temperature and density, line ratios dependent on electron temperature or density have also been used successfully to validate and monitor the calibration. The results indicate that, within the uncertainties, the radiometric calibration has been validated and maintained over the first six years of observations apart from three specific wavelengths, 338.98 angstrom, 315.0 angstrom, and 311.8 angstrom. Problems with lines at 608.4 angstrom, 303.4 angstrom (seen in second order), 335.4 angstrom, and 360.7 angstrom are attributed to difficulties with the burn-in correction. C1 CCLRC Rutherford Appleton Lab, Didcot OX11 0QX, Oxon, England. USN, Res Lab, EO Hulburt Ctr Space Res, Washington, DC 20375 USA. Catania Univ, Dipartimento Fis & Astron, I-95123 Catania, Italy. Univ Strathclyde, Dept Phys, Glasgow G4 0NG, Lanark, Scotland. NASA GSFC, Commun GSI L3, Greenbelt, MD 20771 USA. RP Lang, J (reprint author), CCLRC Rutherford Appleton Lab, Didcot OX11 0QX, Oxon, England. EM J.Lang@rl.ac.uk RI Thompson, William/D-7376-2012; Lanzafame, Alessandro/A-1129-2012 OI Lanzafame, Alessandro/0000-0002-2697-3607 NR 52 TC 4 Z9 5 U1 0 U2 1 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD FEB PY 2007 VL 463 IS 1 BP 339 EP 351 DI 10.1051/0004-6361:20054477 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 132KO UT WOS:000243941900033 ER PT J AU Parkinson, CD Liang, MC Hartman, H Hansen, CJ Tinetti, G Meadows, V Kirschvink, JL Yung, YL AF Parkinson, C. D. Liang, M. -C. Hartman, H. Hansen, C. J. Tinetti, G. Meadows, V. Kirschvink, J. L. Yung, Y. L. TI Enceladus: Cassini observations and implications for the search for life SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE astrobiology; planets and satellites : general; planets and satellites : formation; planets and satellites : individual : Saturn; planets and satellites : individual : Enceladus; solar system : general; astrochemistry ID CARBONACEOUS CHONDRITES; HIGH-RESOLUTION; CROSS-SECTIONS; ICE SHELL; EUROPA; WATER; ION; SURFACE; ATMOSPHERE; HYDROGEN AB Aims. The recent Cassini discovery of water vapor plumes ejected from the south pole of the Saturnian satellite, Enceladus, presents a unique window of opportunity for the detection of extant life in our solar system. Methods. With its significant geothermal energy source propelling these plumes > 80 km from the surface of the moon and the ensuing large temperature gradient with the surrounding environment, it is possible to have the weathering of rocks by liquid water at the rock/liquid interface. For the cases of the putatively detected salt-water oceans beneath the ice crusts of Europa and Callisto, an isolated subsurface ocean without photosynthesis or contact with an oxidizing atmosphere will approach chemical equilibrium and annihilate any ecosystems dependent on redox gradients unless there is a substantial alternative energy source. This thermodynamic tendency imposes severe constraints on any biota that is based on chemical energy. On Enceladus, the weathering of rocks by liquid water and any concomitant radioactive emissions are possible incipient conditions for life. If there is CO, CO2 and NH3 present in the spectra obtained from the plume, then this is possible evidence that amino acids could be formed at the rock/liquid interface of Enceladus. The combination of a hydrological cycle, chemical redox gradient and geochemical cycle give favorable conditions for life. Results. We discuss the search for signatures of these species and organics in the Cassini UVIS spectra of the plume and implications for the possible detection of life. C1 CALTECH, Div Geol & Planetary Sci, Pasadena, CA 91125 USA. Univ Michigan, Dept Atmospher Ocean & Space Sci, Ann Arbor, MI 48109 USA. MIT, Ctr Biomed Engn, Cambridge, MA 02139 USA. CALTECH, Jet Propuls Lab, Pasadena, CA 91125 USA. European Space Agcy, Inst Astrophys Paris, Observ Paris, Paris, France. CALTECH, Spitzer Sci Ctr, Pasadena, CA 91125 USA. RP Parkinson, CD (reprint author), CALTECH, Div Geol & Planetary Sci, Pasadena, CA 91125 USA. EM cdp@gps.caltech.edu OI Tinetti, Giovanna/0000-0001-6058-6654 NR 51 TC 22 Z9 22 U1 10 U2 33 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD FEB PY 2007 VL 463 IS 1 BP 353 EP 357 DI 10.1051/0004-6361:20065773 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 132KO UT WOS:000243941900034 ER PT J AU Guidorzi, C Gomboc, A Kobayashi, S Mundell, CG Rol, E Bode, MF Carter, D La Parola, V Melandri, A Monfardini, A Mottram, CJ O'Brien, PT Page, KL Sakamoto, T Smith, RJ Steele, IA Tanvir, NR AF Guidorzi, C. Gomboc, A. Kobayashi, S. Mundell, C. G. Rol, E. Bode, M. F. Carter, D. La Parola, V. Melandri, A. Monfardini, A. Mottram, C. J. O'Brien, P. T. Page, K. L. Sakamoto, T. Smith, R. J. Steele, I. A. Tanvir, N. R. TI The circumburst environment of a FRED GRB: study of the prompt emission and X-ray/optical afterglow of GRB 051111 SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE gamma rays : bursts; X-rays : individuals : GRB 051111; dust, extinction; radiation mechanisms : non thermal ID GAMMA-RAY BURST; COSMIC CHEMICAL EVOLUTION; HOST GALAXIES; LIGHT CURVES; MILKY-WAY; DUST; ABSORPTION; INTERSTELLAR; ABUNDANCES; SYSTEM AB Aims. We report a multi-wavelength analysis of the prompt emission and early afterglow of GRB 051111 and discuss its properties in the context of current fireball models. Methods. The detection of GRB 051111 by the Burst Alert Telescope on-board Swift triggered early BVRi' observations with the 2-m robotic Faulkes Telescope North in Hawaii, as well as X-ray observations with the Swift X-Ray Telescope. Results. The prompt gamma-ray emission shows a classical FRED profile. The optical afterglow light curves are fitted with a broken power law, with alpha(1) = 0.35 to alpha(2) = 1.35 and a break time around 12 min after the GRB. Although contemporaneous X-ray observations were not taken, a power law connection between the gamma-ray tail of the FRED temporal profile and the late XRT flux decay is feasible. Alternatively, if the X-ray afterglow tracks the optical decay, this would represent one of the first GRBs for which the canonical steep-shallow-normal decay typical of early X-ray afterglows has been monitored optically. We present a detailed analysis of the intrinsic extinction, elemental abundances and spectral energy distribution. From the absorption measured in the low X-ray band we find possible evidence for an overabundance of some a elements such as oxygen, [O/Zn] = 0.7 +/- 0.3, or, alternatively, for a significant presence of molecular gas. The IR-to-X-ray Spectral Energy Distribution measured at 80 min after the burst is consistent with the cooling break lying between the optical and X-ray bands. Extensive modelling of the intrinsic extinction suggests dust with big grains or grey extinction profiles. The early optical break is due either to an energy injection episode or, less probably, to a stratified wind environment for the circumburst medium. C1 Liverpool John Moores Univ, Astrophys Res Inst, Birkenhead CH41 1LD, Merseyside, England. Univ Ljubljana, Fac Math & Phys, Ljubljana 1000, Slovenia. Univ Leicester, Dept Phys & Astron, Leicester LE1 7RH, Leics, England. INAF, Sez Palermo, I-90146 Palermo, Italy. IRST, ITC, I-38050 Povo, TN, Italy. INFN, I-38050 Povo, TN, Italy. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Hertfordshire, Ctr Astrophys Res, Hatfield AL10 9AB, Herts, England. RP Guidorzi, C (reprint author), Osserv Astron Brera, INAF, Via Bianchi 46, I-23807 Merate, LC, Italy. EM cristiano.guidorzi@brera.inaf.it OI La Parola, Valentina/0000-0002-8087-6488 NR 80 TC 15 Z9 15 U1 0 U2 0 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD FEB PY 2007 VL 463 IS 2 BP 539 EP 550 DI 10.1051/0004-6361:20065974 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 134FU UT WOS:000244069700016 ER PT J AU Branduardi-Raymont, G Bhardwaj, A Elsner, RF Gladstone, GR Ramsay, G Rodriguez, P Soria, R Waite, JH Cravens, TE AF Branduardi-Raymont, G. Bhardwaj, A. Elsner, R. F. Gladstone, G. R. Ramsay, G. Rodriguez, P. Soria, R. Waite, J. H., Jr. Cravens, T. E. TI A study of Jupiter's aurorae with XMM-Newton SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE planets and satellites : general; planets and satellites : individual : Jupiter; X-rays : general ID BREMSSTRAHLUNG X-RAYS; SOLAR-WIND IONS; EMISSION; PRECIPITATION; SPECTRA AB We present a detailed analysis of Jupiter's X-ray (0.2-10 keV) auroral emissions as observed over two XMM-Newton revolutions in Nov. 2003 and compare it with that of an earlier observation in Apr. 2003. We discover the existence of an electron bremsstrahlung component in the aurorae, which accounts for essentially all the X-ray flux above 2 keV: its presence had been predicted but never detected for lack of sensitivity of previous X-ray missions. This bremsstrahlung component varied significantly in strength and spectral shape over the 3.5 days covered by the Nov. 2003 observation, displaying substantial hardening of the spectrum with increasing flux. This variability may be linked to the strong solar activity taking place at the time, and may be induced by changes in the acceleration mechanisms inside Jupiter's magnetosphere. As in Apr. 2003, the auroral spectra below 2 keV are best fitted by a superposition of line emission most likely originating from ion charge exchange, with OVII playing the dominant role. We still cannot resolve conclusively the ion species responsible for the lowest energy lines (around 0.3 keV), so the question of the origin of the ions (magnetospheric or solar wind) is still open. It is conceivable that both scenarios play a role in what is certainly a very complex planetary structure. High resolution spectra of the whole planet obtained with the XMM-Newton Reflection Grating Spectrometer in the range 0.5-1 keV clearly separate emission lines (mostly of iron) originating at low latitudes on Jupiter from the auroral lines due to oxygen. These are shown to possess very broad wings which imply velocities of similar to 5000 km s(-1). Such speeds are consistent with the energies at which precipitating and charge exchanging oxygen ions are expected to be accelerated in Jupiter's magnetosphere. Overall we find good agreement between our measurements and the predictions of recently developed models of Jupiter's auroral processes. C1 UCL, Mullard Space Sci Lab, Dorking RH5 6NT, Surrey, England. Vikram Sarabhai Space Ctr, Space Phys Lab, Trivandrum 695022, Kerala, India. NSSTC XD12, NASA Marshall Space Flight Ctr, Huntsville, AL 35805 USA. SW Res Inst, San Antonio, TX 78228 USA. XMM Newton SOC, Madrid 28080, Spain. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Michigan, Ann Arbor, MI 48109 USA. Univ Kansas, Dept Phys & Astron, Lawrence, KS 66045 USA. RP Branduardi-Raymont, G (reprint author), UCL, Mullard Space Sci Lab, Holmbury St Mary, Dorking RH5 6NT, Surrey, England. EM gbr@mssl.ucl.ac.uk OI Bhardwaj, Anil/0000-0003-1693-453X NR 34 TC 41 Z9 41 U1 1 U2 5 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD FEB PY 2007 VL 463 IS 2 BP 761 EP 774 DI 10.1051/0004-6361:20066406 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 134FU UT WOS:000244069700042 ER PT J AU Min, M Waters, LBFM de Koter, A Hovenier, JW Keller, LP Markwick-Kemper, F AF Min, M. Waters, L. B. F. M. de Koter, A. Hovenier, J. W. Keller, L. P. Markwick-Kemper, F. TI The shape and composition of interstellar silicate grains SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE dust, extinction; infrared : ISM ID PROTOPLANETARY ACCRETION DISKS; RAY OPTICS APPROXIMATION; COMET HALE-BOPP; INTERPLANETARY DUST; SEMITRANSPARENT PARTICLES; CRYSTALLINE SILICATES; AMORPHOUS SILICATES; INFRARED EXTINCTION; LIGHT-SCATTERING; POROUS GRAINS AB We investigate the composition and shape distribution of silicate dust grains in the interstellar medium. The effects of the amount of magnesium and iron in the silicate lattice are studied in detail. We fit the spectral shape of the interstellar 10 mu m extinction feature as observed towards the galactic center using various particle shapes and dust materials. We use very irregularly shaped coated and non- coated porous Gaussian Random Field particles as well as a statistical approach to model shape effects. For the dust materials we use amorphous and crystalline silicates with various composition as well as silicon carbide (SiC). The results of our analysis of the 10 mu m feature are used to compute the shape of the 20 mu m silicate feature and to compare this with observations of this feature towards the galactic center. By using realistic particle shapes to fit the interstellar extinction spectrum we are, for the first time, able to derive the magnesium fraction in interstellar silicates. We find that the interstellar silicates are highly magnesium rich (Mg/(Fe + Mg) > 0.9) and that the stoichiometry lies between pyroxene and olivine type silicates (O/Si approximate to 3.5). This composition is not consistent with that of the glassy material found in GEMS in interplanetary dust particles indicating that the amorphous silicates found in the Solar system are, in general, not unprocessed remnants from the interstellar medium. Also, we find that a significant fraction of silicon carbide (similar to 3%) is present in the interstellar dust grains. We discuss the implications of our results for the formation and evolutionary history of cometary and circumstellar dust. We argue that the fact that crystalline silicates in cometary and circumstellar grains are almost purely magnesium silicates is a natural consequence of our findings that the amorphous silicates from which they were formed were already magnesium rich. C1 Univ Amsterdam, Astron Inst Anton Pannekoek, NL-1098 SJ Amsterdam, Netherlands. Katholieke Univ Leuven, Sterrekundig Inst, B-3001 Heverlee, Belgium. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. Univ Virginia, Dept Astron, Charlottesville, VA 22904 USA. RP Min, M (reprint author), Univ Amsterdam, Astron Inst Anton Pannekoek, Kruislaan 403, NL-1098 SJ Amsterdam, Netherlands. EM mmin@science.uva.nl RI Kemper, Francisca/D-8688-2011 OI Kemper, Francisca/0000-0003-2743-8240 NR 57 TC 94 Z9 94 U1 0 U2 6 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD FEB PY 2007 VL 462 IS 2 BP 667 EP 676 DI 10.1051/0004-6361:20065436 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 128VH UT WOS:000243686600027 ER PT J AU Perri, M Maselli, A Giommi, P Massaro, E Nesci, R Tramacere, A Capalbi, M Cusumano, G Chincarini, G Tagliaferri, G Burrows, DN Berk, DV Gehrels, N Sambruna, RM AF Perri, M. Maselli, A. Giommi, P. Massaro, E. Nesci, R. Tramacere, A. Capalbi, M. Cusumano, G. Chincarini, G. Tagliaferri, G. Burrows, D. N. Berk, D. V. Gehrels, N. Sambruna, R. M. TI Swift XRT and UVOT deep observations of the high-energy peaked BL Lacertae object PKS 0548-322 close to its brightest state SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE radiation mechanisms : non-thermal; galaxies : active; galaxies : BL Lacertae objects : individual : PKS 0548-322; X-rays : galaxies ID LOG-PARABOLIC SPECTRA; ACTIVE GALACTIC NUCLEI; X-RAY TELESCOPE; LAC OBJECTS; PARTICLE-ACCELERATION; PKS 0548-322; BLAZARS; BAND; ENVIRONMENT; EMISSION AB Aims. We observed the high-energy peaked BL Lac object PKS 0548-322 (BZB J0550-3216) with Swift to study the temporal and spectral properties of its synchrotron emission simultaneously in the optical, ultraviolet, and X-ray energy bands. Methods. We carried out a spectral analysis of 5 Swift XRT and UVOT observations of PKS 0548-322 taken over the period April-June 2005. Results. The X-ray flux of this BL Lac source was found to be approximately constant at a level of F(2-10 keV) similar or equal to 4 x 10(-11) erg cm(-2) s(-1) which is a factor of 2 brighter than when observed by BeppoSAX in 1999 and close to the maximum intensity reported in the Einstein Slew Survey. The very good statistics obtained in the 0.3-10 keV Swift X-ray spectrum allowed us to detect highly significant deviations from a simple power-law spectral distribution. A log-parabolic model describes the X-ray data well and gives a best-fit curvature parameter of 0.18 and a peak energy in the spectral energy distribution of about 2 keV. The UV spectral data from Swift UVOT join closely with a power-law extrapolation of the soft X-ray data points, suggesting that the same component is responsible for the observed emission in the two bands. The combination of synchrotron peak in the X-ray band and the high-intensity state confirms PKS 0548-322 as a prime target for TeV observations. X-ray monitoring and coordinated TeV campaigns are highly advisable. C1 ASI Sci Data Ctr, I-00185 Frascati, Italy. Univ Roma La Sapienza, Dipartimento Fis, I-00185 Rome, Italy. Unita Osservaz Universo, Agenzia Spaziale Italiana, I-00198 Rome, Italy. INAF, Ist Astrofis Spaziale & Fis Cosm, Sez Palermo, I-90146 Palermo, Italy. INAF Osservatorio Astron Brera, I-23807 Merate, Italy. Univ Milan, Dipartimento Fis, I-20126 Milan, Italy. Penn State Univ, Dept Astron & Astrophys, University Pk, PA 16802 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Perri, M (reprint author), ASI Sci Data Ctr, Via Galileo Galilei, I-00185 Frascati, Italy. EM perri@asdc.asi.it RI Gehrels, Neil/D-2971-2012; OI giommi, paolo/0000-0002-2265-5003; Cusumano, Giancarlo/0000-0002-8151-1990; Tramacere, Andrea/0000-0002-8186-3793; Perri, Matteo/0000-0003-3613-4409; Tagliaferri, Gianpiero/0000-0003-0121-0723 NR 39 TC 10 Z9 10 U1 0 U2 0 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD FEB PY 2007 VL 462 IS 3 BP 889 EP 893 DI 10.1051/0004-6361:20066063 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 129IJ UT WOS:000243721900017 ER PT J AU Capalbi, M Malesani, D Perri, M Giommi, P Covino, S Cusumano, G Mangano, V Mineo, T Campana, S Chincarini, G La Parola, V Moretti, A Romano, P Tagliaferri, G Angelini, L Boyd, P Burrows, DN Godet, O Hill, JE Kennea, JA Marshall, F O'Brien, PT Gehrels, N AF Capalbi, M. Malesani, D. Perri, M. Giommi, P. Covino, S. Cusumano, G. Mangano, V. Mineo, T. Campana, S. Chincarini, G. La Parola, V. Moretti, A. Romano, P. Tagliaferri, G. Angelini, L. Boyd, P. Burrows, D. N. Godet, O. Hill, J. E. Kennea, J. A. Marshall, F. O'Brien, P. T. Gehrels, N. TI Long-term monitoring of the X-ray afterglow of GRB 050408 with Swift/XRT SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE gamma rays : bursts; X-rays : individual : GRB 050408 ID BURST AFTERGLOWS; LIGHT CURVES; ENERGY INJECTION; VLT OBSERVATIONS; STAR-FORMATION; JET STRUCTURE; DUST; TELESCOPE; ENVIRONMENT; EMISSION AB We present observations of the X-ray afterglow of GRB 050408, a gamma-ray burst discovered by HETE-II. Swift began observing the field 42 min after the burst, performing follow-up over a period of 38 d (thus spanning three decades in time). The X-ray light curve showed a steepening with time, similar to many other afterglows. However, the steepening was unusually smooth, over the duration of the XRT observation, with no clear break time. The early decay was too flat to be described in terms of standard models. We therefore explore alternative explanations, such as the presence of a structured afterglow or of long-lasting energy injection into the fireball from the central GRB engine. The lack of a sharp break puts constraints on these two models. In the former case, it may indicate that the angular energy profile of the jet was not a simple power law, while in the second model it implies that injection did not stop abruptly. The late decay may be due either to a standard afterglow (that is with no energy injection), or to a jetted outflow still being refreshed. A significant amount of absorption was present in the X-ray spectrum, corresponding to a rest-frame hydrogen column density N-H = 1.2(- 0.3)(+0.4) x 10(22) cm(-2), indicative of a dense environment. C1 ASI Sci Data Ctr, I-00044 Frascati, Italy. Scuola Int Super Studi Avanzati, SISSA, I-34014 Trieste, Italy. ASI, Unita Osservaz Universo, I-00198 Rome, Italy. INAF Osservatorio Astron Brera, I-23807 Merate, Italy. INAF Ist Astrofis Spaziale & Fis Cosm, Sez Palermo, I-90146 Palermo, Italy. Univ Milan, Dipartimento Fis, I-20126 Milan, Italy. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. Penn State Univ, Dept Astron & Astrophys, University Pk, PA 16802 USA. Univ Leicester, Dept Phys & Astron, Leicester LE1 7RH, Leics, England. Univ Space Res Assoc, Columbia, MD 21044 USA. RP Capalbi, M (reprint author), ASI Sci Data Ctr, Via G Galilei, I-00044 Frascati, Italy. EM capalbi@asdc.asi.it RI Boyd, Patricia/D-3274-2012; Gehrels, Neil/D-2971-2012; OI Mineo, Teresa/0000-0002-4931-8445; giommi, paolo/0000-0002-2265-5003; Cusumano, Giancarlo/0000-0002-8151-1990; moretti, alberto/0000-0002-9770-0315; Perri, Matteo/0000-0003-3613-4409; La Parola, Valentina/0000-0002-8087-6488; Covino, Stefano/0000-0001-9078-5507; Tagliaferri, Gianpiero/0000-0003-0121-0723 NR 59 TC 3 Z9 3 U1 0 U2 0 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD FEB PY 2007 VL 462 IS 3 BP 913 EP 918 DI 10.1051/0004-6361:20065388 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 129IJ UT WOS:000243721900020 ER PT J AU Dale, DA de Paz, AG Gordon, KD Hanson, HM Armus, L Bendo, GJ Bianchi, L Block, M Boissier, S Boselli, A Buckalew, BA Buat, V Burgarella, D Calzetti, D Cannon, JM Engelbracht, CW Helou, G Hollenbach, DJ Jarrett, TH Kennicutt, RC Leitherer, C Li, A Madore, BF Martin, DC Meyer, MJ Murphy, EJ Regan, MW Roussel, H Smith, JDT Sosey, ML Thilker, DA Walter, F AF Dale, D. A. de Paz, A. Gil Gordon, K. D. Hanson, H. M. Armus, L. Bendo, G. J. Bianchi, L. Block, M. Boissier, S. Boselli, A. Buckalew, B. A. Buat, V. Burgarella, D. Calzetti, D. Cannon, J. M. Engelbracht, C. W. Helou, G. Hollenbach, D. J. Jarrett, T. H. Kennicutt, R. C. Leitherer, C. Li, A. Madore, B. F. Martin, D. C. Meyer, M. J. Murphy, E. J. Regan, M. W. Roussel, H. Smith, J. D. T. Sosey, M. L. Thilker, D. A. Walter, F. TI An ultraviolet-to-radio broadband spectral atlas of nearby galaxies SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : photometry; infrared : galaxies; infrared : ISM; ultraviolet : galaxies ID STAR-FORMING GALAXIES; 1.49 GHZ ATLAS; STARBURST GALAXIES; ENERGY-DISTRIBUTIONS; INFRARED-EMISSION; DUST ATTENUATION; SPIRAL GALAXIES; FORMATION RATES; DISK GALAXIES; INTERNAL EXTINCTION AB The ultraviolet-to-radio continuum spectral energy distributions are presented for all 75 galaxies in the Spitzer Infrared Nearby Galaxies Survey (SINGS). A principal component analysis of the sample shows that most of the sample's spectral variations stem from two underlying components, one representative of a galaxy with a low infrared-to-ultraviolet ratio and one representative of a galaxy with a high infrared-to-ultraviolet ratio. The influence of several parameters on the infrared-to-ultraviolet ratio is studied (e. g., optical morphology, disk inclination, far-infrared color, ultraviolet spectral slope, and star formation history). Consistent with our understanding of normal star-forming galaxies, the SINGS sample of galaxies in comparison to more actively star-forming galaxies exhibits a larger dispersion in the infrared-to-ultraviolet versus ultraviolet spectral slope correlation. Early-type galaxies, exhibiting low star formation rates and high optical surface brightnesses, have the most discrepant infrared-to-ultraviolet correlation. These results suggest that the star formation history may be the dominant regulator of the broadband spectral variations between galaxies. Finally, a new discovery shows that the 24 mu m morphology can be a useful tool for parameterizing the global dust temperature and ultraviolet extinction in nearby galaxies. The dust emission in dwarf/irregular galaxies is clumpy and warm accompanied by low ultraviolet extinction, while in spiral galaxies there is typically a much larger diffuse component of cooler dust and average ultraviolet extinction. For galaxies with nuclear 24 mu m emission, the dust temperature and ultraviolet extinction are relatively high compared to disk galaxies. C1 Univ Wyoming, Dept Phys & Astron, Laramie, WY 82071 USA. Univ Complutense Madrid, Dept Astrofis, E-28040 Madrid, Spain. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. CALTECH, Spitzer Sci Ctr, Pasadena, CA 91125 USA. Univ London Imperial Coll Sci Technol & Med, Blackett Lab, Astrophys Grp, London SW7 2AZ, England. Johns Hopkins Univ, Ctr Astrophys Sci, Baltimore, MD 21218 USA. Carnegie Inst Sci, Carnegie Observ, Pasadena, CA USA. Lab Astrophys Marseille, Marseille, France. CALTECH, Astron Opt, Pasadena, CA 91125 USA. Space Telescope Sci Inst, Baltimore, MD 21218 USA. Wesleyan Univ, Dept Astron, Middletown, CT 06459 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ Cambridge, Inst Astron, Cambridge CB2 1TN, England. Univ Missouri, Dept Phys & Astron, Columbia, MO 65211 USA. Yale Univ, Dept Astron, New Haven, CT 06520 USA. Max Planck Inst Astron, D-69117 Heidelberg, Germany. RP Dale, DA (reprint author), Univ Wyoming, Dept Phys & Astron, Laramie, WY 82071 USA. EM ddale@uwyo.edu RI Gil de Paz, Armando/J-2874-2016 OI Gil de Paz, Armando/0000-0001-6150-2854 NR 84 TC 263 Z9 264 U1 1 U2 5 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X EI 1538-4357 J9 ASTROPHYS J JI Astrophys. J. PD FEB 1 PY 2007 VL 655 IS 2 BP 863 EP 884 DI 10.1086/510362 PN 1 PG 22 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 129JS UT WOS:000243726000017 ER PT J AU Zhang, B Liang, EW Page, KL Grupe, D Zhang, BB Barthelmy, SD Burrows, DN Campana, S Chincarini, G Gehrels, N Kobayashi, S Meszaros, P Moretti, A Nousek, JA O'Brien, PT Osborne, JP Roming, PWA Sakamoto, T Schady, P Willingale, R AF Zhang, Bing Liang, Enwei Page, Kim L. Grupe, Dirk Zhang, Bin-Bin Barthelmy, Scott D. Burrows, David N. Campana, Sergio Chincarini, Guido Gehrels, Neil Kobayashi, Shiho Meszaros, Peter Moretti, Alberto Nousek, John A. O'Brien, Paul T. Osborne, Julian P. Roming, Peter W. A. Sakamoto, Takanori Schady, Patricia Willingale, Richard TI GRB radiative efficiencies derived from the swift data: GRBs versus XRFs, long versus short SO ASTROPHYSICAL JOURNAL LA English DT Review DE gamma rays : bursts; methods : statistical; radiation mechanisms : nonthermal; shock waves ID GAMMA-RAY-BURSTS; AFTERGLOW LIGHT CURVES; CONTINUOUS ENERGY INJECTION; INTERNAL-SHOCK MODEL; PHYSICAL PARAMETERS; MILLISECOND PULSARS; 2-COMPONENT JET; ALERT TELESCOPE; FIREBALL MODEL; KINETIC-ENERGY AB We systematically analyze the prompt emission and the early afterglow data of a sample of 31 GRBs detected by Swift before 2005 September and estimate the GRB radiative efficiency. BAT's narrow band inhibits a precise determination of the GRB spectral parameters, and we have developed a method to estimate these parameters with the hardness ratio information. The shallow decay component commonly existing in early X-ray afterglows, if interpreted as continuous energy injection in the external shock, suggests that the GRB efficiencies previously derived from the late-time X-ray data were not reliable. We calculate two radiative efficiencies using the afterglow kinetic energy E-K derived at the putative deceleration time (t(dec)) and at the break time (t(b)), when the energy injection phase ends, respectively. At tb XRFs appear to be less efficient than normal GRBs. However, when we analyze the data at tdec, XRFs are found to be as efficient as GRBs. Short GRBs have similar radiative efficiencies to long GRBs despite of their different progenitors. Twenty-two bursts in the sample are identified to have the afterglow cooling frequency below the X-ray band. Assuming epsilon(e) 0:1, we find eta(gamma)(t(b)) usually < 10% and eta(gamma)(t(dec)) varying from a few percent to > 90%. Nine GRBs in the sample have the afterglow cooling frequency above the X-ray band for a very long time. This suggests a very small epsilon(B) and/or a very low ambient density n. C1 Univ Nevada, Dept Phys, Las Vegas, NV 89154 USA. Guangxi Univ, Dept Phys, Nanning 530004, Peoples R China. Univ Leicester, Dept Phys & Astron, Leicester LE1 7RH, Leics, England. Penn State Univ, Dept Astron & Astrophys, University Pk, PA 16802 USA. Chinese Acad Sci, Natl Astron Observ, Yunnan Observ, Kunming, Peoples R China. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Osserv Astron Brera, INAF, Merate, Italy. Univ Milano Bicocca, Dipartimento Fis, Milan, Italy. Liverpool John Moores Univ, Astrophys Res Inst, Birkenhead, Merseyside, England. Penn State Univ, Dept Phys, University Pk, PA 16802 USA. RP Zhang, B (reprint author), Univ Nevada, Dept Phys, Las Vegas, NV 89154 USA. EM bzhang@physics.unlv.edu RI Gehrels, Neil/D-2971-2012; Barthelmy, Scott/D-2943-2012; Zhang, Binbin/C-9035-2013; OI Zhang, Binbin/0000-0003-2002-116X; Campana, Sergio/0000-0001-6278-1576 NR 121 TC 142 Z9 142 U1 1 U2 9 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X EI 1538-4357 J9 ASTROPHYS J JI Astrophys. J. PD FEB 1 PY 2007 VL 655 IS 2 BP 989 EP 1001 DI 10.1086/510110 PN 1 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 129JS UT WOS:000243726000027 ER PT J AU Monnier, JD Tuthill, PG Danchi, WC Murphy, N Harries, TJ AF Monnier, J. D. Tuthill, P. G. Danchi, W. C. Murphy, N. Harries, T. J. TI The Keck aperture-masking experiment: Near-infrared sizes of dusty Wolf-Rayet stars SO ASTROPHYSICAL JOURNAL LA English DT Article DE binaries : general; circumstellar matter; instrumentation : interferometers; radiative transfer; stars : individual ( WR 11, gamma Vel, WR 48a, WR 76, WR 95, WR 98a, WR 104, WR 106, WR 112, WR 113, WR 118, WR 140, CV Ser); stars : winds, outflows; stars : Wolf-Rayet ID RADIO-CONTINUUM MEASUREMENTS; VELORUM BINARY-SYSTEM; NONTHERMAL EMISSION; ADAPTIVE OPTICS; PINWHEEL NEBULA; PROPER MOTIONS; INTERFEROMETRY; COMPANIONS; PARAMETERS; TELESCOPE AB We report the results of a high angular resolution near-infrared survey of dusty Wolf-Rayet stars using the Keck I Telescope, including new multiwavelength images of the pinwheel nebulae WR 98a, WR 104, and WR 112. Angular sizes were measured for an additional eight dusty Wolf-Rayet stars using aperture- masking interferometry, allowing us to probe characteristic sizes down to similar to 20 mas (similar to 40 AU for typical sources). With angular sizes and specific fluxes, we can directly measure the wavelength-dependent surface brightness and size relations for our sample. We discovered tight correlations of these properties within our sample that could not be explained by simple spherically symmetric dust shells or even the more realistic "pinwheel nebula'' (three-dimensional) radiative transfer model, when using Zubko's optical constants. While the tightly correlated surface brightness relations we uncovered offer compelling indirect evidence of a shared and distinctive dust shell geometry among our sample, long-baseline interferometers should target the marginally resolved objects in our sample in order to conclusively establish the presence or absence of the putative underlying colliding-wind binaries thought to produce the dust shells around WC Wolf-Rayet stars. C1 Univ Michigan, Dept Astron, Ann Arbor, MI 48109 USA. Univ Sydney, Sch Phys, Sydney, NSW 2006, Australia. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Exeter, Sch Phys, Exeter EX4 4QJ, Devon, England. RP Monnier, JD (reprint author), Univ Michigan, Dept Astron, Ann Arbor, MI 48109 USA. RI Murphy, Nicholas/C-6176-2009; OI Murphy, Nicholas/0000-0001-6628-8033 NR 47 TC 20 Z9 21 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD FEB 1 PY 2007 VL 655 IS 2 BP 1033 EP 1045 DI 10.1086/509873 PN 1 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 129JS UT WOS:000243726000031 ER PT J AU Leggett, SK Saumon, D Marley, MS Geballe, TR Golimowski, DA Stephens, D Fan, X AF Leggett, S. K. Saumon, D. Marley, M. S. Geballe, T. R. Golimowski, D. A. Stephens, D. Fan, X. TI 3.6-7.9 mu m photometry of L and T dwarfs and the prevalence of vertical mixing in their atmospheres SO ASTROPHYSICAL JOURNAL LA English DT Article DE infrared : stars; stars : low-mass, brown dwarfs ID SPITZER-SPACE-TELESCOPE; INFRARED SPECTROGRAPH IRS; DIGITAL SKY SURVEY; BROWN DWARF; SPECTRAL CLASSIFICATION; CARBON-MONOXIDE; GIANT PLANETS; GLIESE 229B; ULTRACOOL DWARFS; ADAPTIVE OPTICS AB We present new L' (3.75 mu m) photometry of six L and T dwarfs, and M' (4.70 mu m) photometry of 10 L and T dwarfs, observed at the Gemini (North) Observatory, and new 3.55, 4.49, 5.73, and 7.87 mu m photometry of nine L and T dwarfs, obtained with the Spitzer Space Telescope. The sample includes unusually blue and red dwarfs selected from our near infrared studies. The data are combined with previously published L', M', and Spitzer photometry of L and T dwarfs, and trends of colors with spectral type and other colors are examined. Recent model atmospheres by Marley and Saumon are used to generate synthetic colors for ranges of effective temperature, gravity, grain sedimentation efficiency, metallicity, and vertical mixing efficiency. We explore how these parameters affect the mid-infrared colors of L and T dwarfs and find that the data are modeled satisfactorily only if substantial vertical mixing occurs in both L and T dwarf atmospheres. The location and range of the L and T dwarf sequences in IRAC color-color and color- magnitude diagrams is also only reproduced if this mixing occurs, with a range of efficiency described by K-zz similar to 10(2)-10(6) cm(2) s(-1). The colors of the unusually red dwarfs are best reproduced by nonequilibrium models with low sedimentation efficiency, i.e., thick cloud decks, and the colors of the unusually blue dwarfs by nonequilibrium models with high sedimentation efficiency, i.e., thin cloud decks. The K-L' and Spitzer [3:55] - [4:49] colors can be used as indicators of effective temperature for L and T dwarfs, but care must be taken to include gravity and metallicity effects for late-T dwarfs and vertical mixing for both late-L and T dwarfs. C1 Gemini Observ, Hilo, HI USA. Los Alamos Natl Lab, Los Alamos, NM USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD USA. Univ Arizona, Steward Observ, Tucson, AZ USA. RP Leggett, SK (reprint author), Gemini Observ, Hilo, HI USA. EM sleggett@gemini.edu RI Marley, Mark/I-4704-2013; OI Leggett, Sandy/0000-0002-3681-2989 NR 59 TC 66 Z9 66 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD FEB 1 PY 2007 VL 655 IS 2 BP 1079 EP 1094 DI 10.1086/510014 PN 1 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 129JS UT WOS:000243726000034 ER PT J AU Ofman, L AF Ofman, L. TI Three-dimensional MHD model of wave activity in a coronal active region SO ASTROPHYSICAL JOURNAL LA English DT Article DE MHD; Sun : corona; Sun : flares; Sun : magnetic fields; waves ID DOPPLER-SHIFT OSCILLATIONS; BRAGG CRYSTAL SPECTROMETER; LOOP OSCILLATIONS; TRANSVERSE OSCILLATIONS; NUMERICAL SIMULATIONS; ALFVEN WAVES; SOLAR-FLARE; VERTICAL OSCILLATIONS; RESONANT ABSORPTION; TRANSITION-REGION AB MHD wave activity associated with a flare was observed in coronal active region AR 8270 in the extreme ultraviolet (EUV) by the Transition Region and Coronal Explorer (TRACE) satellite on 1998 July 14. In this study, a three-dimensional MHD model of the active region field was initialized using a National Solar Observatory (NSO) Kitt Peak magnetogram and potential extrapolation of the magnetic field, together with gravitationally stratified density. To model the observed wave activity following the flare, a velocity pulse was launched into a model active region from below. It was found that the global oscillations in the model active region are in good qualitative agreement with observations. The main difference between the observations and the model is in the oscillation of several individual loops that damp on longer timescales compared to the corresponding magnetic field line oscillation damping in the model. C1 Catholic Univ Amer, Dept Phys, Greenbelt, MD USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Ofman, L (reprint author), Catholic Univ Amer, Dept Phys, Greenbelt, MD USA. EM Leon.Ofman@gsfc.nasa.gov NR 59 TC 45 Z9 45 U1 1 U2 4 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD FEB 1 PY 2007 VL 655 IS 2 BP 1134 EP 1141 DI 10.1086/510012 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 129JS UT WOS:000243726000039 ER PT J AU Gorjian, V Cleary, K Werner, MW Lawrence, CR AF Gorjian, V. Cleary, K. Werner, M. W. Lawrence, C. R. TI A relation between the mid-infrared [Ne V] 14.3 mu m and [Ne III] 15.6 mu m lines in active Galactic nuclei SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : active; galaxies : ISM; galaxies : nuclei; galaxies : Seyfert; line : formation; quasars : emission lines ID SPITZER-SPACE-TELESCOPE; INFRARED SPECTROGRAPH; GALAXIES; SPECTRA; DIAGNOSTICS; QUASARS; DUSTY; IRS AB We present a strong correlation between the [Ne v] 14.3 mu m and [ Ne III] 15.6 mm emission lines arising from the narrow-line regions (NLRs) of active galactic nuclei (AGNs), spanning 4 orders of magnitude in luminosity. The data are compiled primarily from Spitzer Space Telescope observations of nearby Seyfert galaxies (median) and 3C radio sources (median). This correlation is consistent with earlier studies in the z = 0.01 z = 0.52 optical/UV bands showing that line ratios arising in the NLRs are remarkably constant across AGNs. We also show that the correlation allows only a very narrow range in ionization parameter for simple photoionization models. The observed correlation will place tight constraints on alternative models, which predict constant line ratios over a broader range in ionization parameter. C1 CALTECH, Jet Propuls Lab, Pasadena, CA USA. RP Gorjian, V (reprint author), CALTECH, Jet Propuls Lab, Pasadena, CA USA. NR 18 TC 25 Z9 25 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD FEB 1 PY 2007 VL 655 IS 2 BP L73 EP L76 DI 10.1086/511975 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 129JT UT WOS:000243726100003 ER PT J AU Nielsen, KE Ivarsson, S Gull, TR AF Nielsen, K. E. Ivarsson, S. Gull, T. R. TI Eta Carinae across the 2003.5 minimum: Deciphering the spectrum toward Weigelt D SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article DE circumstellar matter; line : identification; stars : individual (eta Carinae); ultraviolet : stars ID HOMUNCULUS-NEBULA; EMISSION-LINES; STELLAR EJECTA; II EMISSION; FEII; EVENT; VARIABILITY; ULTRAVIOLET; ABSORPTION; SPECTROSCOPY AB Hubble Space Telescope Space Telescope Imaging Spectrograph (HST STIS) near-ultraviolet (NUV) echelle spectra reveal complex structure in the sight line toward the Weigelt D condensation located 0.25" north-northwest of eta Car. In previous studies, the Weigelt condensations have been described to exhibit pure emission line spectra dominated by transitions in mainly singly and doubly ionized iron-group elements. However, high spectral ( R similar to 100, 000) and angular (< 0.060" FWHM) resolutions show that the spectra are modified by circumstellar ( CS) absorption and stellar wind lines formed as far as 1500 AU from the central source. This analysis uses data recorded between 2000 October and 2004 March to monitor changes in emission and absorption as the UV photoexciting fluxes from eta Car drop and later reappear. We compare changes in the wind profiles seen against the star and the CS absorptions to gain knowledge of the properties of the extended wind and the ejecta. Complete spectra, in the wavelength region 2424-2706 angstrom, with line identifications are available in the electronic edition of this paper. C1 Catholic Univ Amer, Washington, DC 20064 USA. NASA, Goddard Space Flight Ctr, Astrophys Sci Div, Greenbelt, MD 20771 USA. RP Nielsen, KE (reprint author), Catholic Univ Amer, Washington, DC 20064 USA. EM nielsen@milkyway.gsfc.nasa.gov RI Gull, Theodore/D-2753-2012 OI Gull, Theodore/0000-0002-6851-5380 NR 38 TC 9 Z9 9 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0067-0049 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD FEB PY 2007 VL 168 IS 2 BP 289 EP 296 DI 10.1086/509785 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 133SI UT WOS:000244033100006 ER PT J AU Fairlie, TD Jacob, DJ Park, RJ AF Fairlie, T. Duncan Jacob, Daniel J. Park, Rokjin J. TI The impact of transpacific transport of mineral dust in the United States SO ATMOSPHERIC ENVIRONMENT LA English DT Article DE transpacific; transport; mineral; dust ID TRANSBOUNDARY POLLUTION INFLUENCES; LONG-RANGE TRANSPORT; ASIAN DUST; ACE-ASIA; TRACE-P; RELATIVE IMPORTANCE; AIR-POLLUTION; NORTH-AMERICA; GOCART MODEL; AFRICAN DUST AB We use a global chemical transport model (GEOS-Chem) to estimate the impact of transpacific transport of mineral dust on aerosol concentrations in North America during 2001. We have implemented two dust mobilization schemes in the model (GOCART and DEAD) and find that the best simulation of North American surface observations with GEOS-Chem is achieved by combining the topographic source used in GOCART with the entrainment scheme used in DEAD. This combination restricts dust emissions to year-round and areas but includes a significant wind threshold for dust mobilization. The model captures the magnitude and seasonal cycle of observed surface dust concentrations over the northern Pacific. It simulates the free tropospheric outflow of dust from Asia observed in the TRACE-P and ACE-Asia aircraft campaigns of spring 2001. It reproduces the timing and distribution of Asian dust outbreaks in North America during April-May. Beyond these outbreaks we find persistent Asian fine dust (averaging 1.2 mu g m(-3)) in surface air over the western United States in spring, with much weaker influence (0.25 mu g m(-3)) in summer and fall. Asian influence over the eastern United States is 30-50% lower. We find that transpacific sources accounted for 41% of the worst dust days in the western United States in 2001. (c) 2006 Elsevier Ltd. All rights reserved. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. Harvard Univ, Dept Earth & Planetary Sci, Cambridge, MA 02138 USA. Harvard Univ, Div Engn, Cambridge, MA 02138 USA. RP Fairlie, TD (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. EM t.d.fairlie@larc.nasa.gov RI Chem, GEOS/C-5595-2014; Park, Rokjin/I-5055-2012 OI Park, Rokjin/0000-0001-8922-0234 NR 60 TC 179 Z9 183 U1 2 U2 33 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1352-2310 EI 1873-2844 J9 ATMOS ENVIRON JI Atmos. Environ. PD FEB PY 2007 VL 41 IS 6 BP 1251 EP 1266 DI 10.1016/j.atmosenv.2006.09.048 PG 16 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA 136OG UT WOS:000244233400013 ER PT J AU Seraji, H Werger, B AF Seraji, Homayoun Werger, Barry TI Theory and experiments in SmartNav rover navigation SO AUTONOMOUS ROBOTS LA English DT Article DE navigation; fuzzy logic; rovers; natural terrain ID TERRAIN-BASED NAVIGATION; SYSTEM AB This paper describes theoretical and experimental results using the SmartNav rule-free fuzzy rover navigation system. SmartNav divides the terrain perceived by the rover into a number of circular sectors, and evaluates each sector using goal and safety preference factors to differentiate between preferred and unpreferred terrain sectors. The goal-preference factor is used to make sector evaluation based on the sector orientation relative to the designated goal position. The safety-preference factors are used to make sector evaluations on the basis of the sector local and regional terrain hazards. Three methods are developed to blend the three sector evaluations in order to find the effective preference factor for each sector. Two sector selection methods are then described in which the sector preference factors are used to find the heading command for the rover. The rover speed command is also computed based on the goal distance and safety-preference factor of the chosen sector. The above navigation steps are continuously repeated throughout the rover motion. Experimental results are presented to demonstrate the navigational capabilities of SmartNav using a commercial Pioneer 2AT rover traversing a simulated Martian terrain at the JPL Mini Mars Yard. C1 CALTECH, NASA, Jet Propuls Lab, Pasadena, CA 91109 USA. RP Seraji, H (reprint author), CALTECH, NASA, Jet Propuls Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 24 TC 2 Z9 2 U1 0 U2 2 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0929-5593 EI 1573-7527 J9 AUTON ROBOT JI Auton. Robot. PD FEB PY 2007 VL 22 IS 2 BP 165 EP 182 DI 10.1007/s10514-006-9011-x PG 18 WC Computer Science, Artificial Intelligence; Robotics SC Computer Science; Robotics GA 135UG UT WOS:000244178800004 ER PT J AU Alexis, MA Rasse, DP Rumpel, C Bardoux, G Pechot, N Schmalzer, P Drake, B Mariotti, A AF Alexis, M. A. Rasse, D. P. Rumpel, C. Bardoux, G. Pechot, N. Schmalzer, P. Drake, B. Mariotti, A. TI Fire impact on C and N losses and charcoal production in a scrub oak ecosystem SO BIOGEOCHEMISTRY LA English DT Article DE carbon cycle; charcoal; fire; CO2 flux; scrub ID SCOTS PINE FORESTS; SOIL ORGANIC-CARBON; SOLID-STATE C-13; BLACK CARBON; BURNING EFFICIENCY; CHEMICAL-COMPOSITION; ABOVEGROUND BIOMASS; BRAZILIAN AMAZONIA; CULTIVATED SOILS; ATMOSPHERIC CO2 AB Fire profoundly modifies the terrestrial C cycle of about 40% of the Earth's land surface. The immediate effect of fire is that of a net loss of C as CO2 gas and soot particles to the atmosphere. Nevertheless, a proportion of the ecosystem biomass is converted into charcoal, which contains highly recalcitrant molecular structures that contribute to long-term C storage. The present study aimed to assess simultaneously losses to the atmosphere and charcoal production rates of C and N compounds as a result of prescription fire in a Florida scrub-oak ecosystem. Pre-fire and post-fire charred and unburned organic matter stocks were determined for vegetation leaves and stems, litter and soil in 20 sub-plots installed in a 30-ha area that was subjected to prescribed fire. Concentrations of C and N were determined, and fluxes among pools and to the atmosphere were derived from these measurements. Soil C and N stocks were unchanged by the fire. Post-fire standing dead biomass contained 30% and 12% of pre-fire vegetation C and N stocks, respectively. In litter, post-fire stocks contained 64% and 83% of pre-fire C and N stocks, respectively. Most of the difference in relative losses between vegetation and litter could be attributed to substantial litter fall of charred and unburned leaves during the fire event. Indeed, an estimated 21% of pre-fire vegetation leaf C was found in the post-fire litter, while the remaining 79% was lost to the atmosphere. About 3/4 of the fire-induced leaf litter fall was in the form of unburned tissue and the remainder was charcoal, which amounted to 5% of pre-fire leaf C stocks. Charcoal production ranged between 4% and 6% of the fire-affected biomass, i.e. the sum of charcoal production and atmospheric losses. This value is below the range of literature values for the transformation of plant tissue into stable soil organic matter through humification processes, which suggests that fire generates a smaller quantity of stable organic C than humification processes over decades and potentially centuries. C1 Ctr INRA Versailles Grignon, Lab Biogeochim & Ecol Milieux Continenaux, F-78850 Thiverval Grignon, France. Norwegian Inst Agr & Environm Res, Bioforsk, N-1432 As, Norway. NASA, Dynamac Corp, Kennedy Space Ctr, FL 32899 USA. RP Alexis, MA (reprint author), Ctr INRA Versailles Grignon, Lab Biogeochim & Ecol Milieux Continenaux, F-78850 Thiverval Grignon, France. EM alexis@grignon.inra.fr RI Rumpel, Cornelia/A-2001-2015; OI Daniel, Rasse/0000-0002-5977-3863; Schmalzer, Paul/0000-0003-2214-0074 NR 54 TC 55 Z9 63 U1 2 U2 37 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0168-2563 J9 BIOGEOCHEMISTRY JI Biogeochemistry PD FEB PY 2007 VL 82 IS 2 BP 201 EP 216 DI 10.1007/s10533-006-9063-1 PG 16 WC Environmental Sciences; Geosciences, Multidisciplinary SC Environmental Sciences & Ecology; Geology GA 126ZN UT WOS:000243554400007 ER PT J AU Segovia-Juarez, JL Colombano, S Kirschner, D AF Segovia-Juarez, Jose L. Colombano, Silvano Kirschner, Denise TI Identifying DNA splice sites using hypernetworks with artificial molecular evolution SO BIOSYSTEMS LA English DT Article; Proceedings Paper CT 6th International Workshop on Information Processing in Cells and Tissues CY AUG 30-SEP 01, 2005 CL St Williams Coll, York, ENGLAND SP Univ York, Dept Elect HO St Williams Coll DE DNA splice sites identification; artificial evolution; hypernetwork learning; molecular networks ID GENE-PREDICTION; MESSENGER-RNA; SEQUENCE; IDENTIFICATION; INFORMATION; NETWORK AB Identifying DNA splice sites is a main task of gene hunting. We introduce the hyper-network architecture as a novel method for finding DNA splice sites. The hypernetwork architecture is a biologically inspired information processing system composed of networks of molecules forming cells, and a number of cells forming a tissue or organism. Its learning is based on molecular evolution. DNA examples taken from GenBank were translated into binary strings and fed into a hypernetwork for training. We performed experiments to explore the generalization performance of hypernetwork learning in this data set by two-fold cross validation. The hypernetwork generalization performance was comparable to well known classification algorithms. With the best hypernetwork obtained, including local information and heuristic rules, we built a system (HyperExon) to obtain splice site candidates. The HyperExon system outperformed leading splice recognition systems in the list of sequences tested. (c) 2006 Elsevier Ireland Ltd. All rights reserved. C1 NASA, Ames Res Ctr, Intelligent Syst Div, Moffett Field, CA 94035 USA. Univ Michigan, Dept Microbiol & Immunol, Ann Arbor, MI 48109 USA. RP Colombano, S (reprint author), NASA, Ames Res Ctr, Intelligent Syst Div, Moffett Field, CA 94035 USA. EM scolombano@mail.arc.nasa.gov OI Segovia-Juarez, Jose/0000-0002-3332-5886 NR 21 TC 6 Z9 9 U1 0 U2 4 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0303-2647 J9 BIOSYSTEMS JI Biosystems PD FEB PY 2007 VL 87 IS 2-3 BP 117 EP 124 DI 10.1016/j.biosystems.2006.09.004 PG 8 WC Biology; Mathematical & Computational Biology SC Life Sciences & Biomedicine - Other Topics; Mathematical & Computational Biology GA 135BJ UT WOS:000244128500004 PM 17116361 ER PT J AU Zwart, SR Hargens, AR Lee, SMC Macias, BR Watenpaugh, DE Tse, K Smith, SM AF Zwart, Sara R. Hargens, Alan R. Lee, Stuart M. C. Macias, Brandon R. Watenpaugh, Donald E. Tse, Kevin Smith, Scott M. TI Lower body negative pressure treadmill exercise as a countermeasure for bed rest-induced bone loss in female identical twins SO BONE LA English DT Article DE exercise; nutrition; osteoporosis; bone turnover markers; weightlessness ID BIOCHEMICAL MARKERS; SPACE-FLIGHT; RESORPTION MARKERS; URINARY-EXCRETION; RAT OSTEOCLASTS; MINERAL DENSITY; MENSTRUAL-CYCLE; WEIGHT-BEARING; CROSS-LINKS; METABOLISM AB Supine weight-bearing exercise within lower body negative pressure (LBNP) alleviates some of the skeletal deconditioning induced by simulated weight-lessness in men. We examined this potential beneficial effect in women. Because dietary acid load affected the degree of bone resorption in men during bed rest, we also investigated this variable in women. Subjects were 7 pairs of female identical twins assigned at random to 2 groups, sedentary bed rest (control) or bed rest with supine treadmill exercise within LBNP. Dietary intake was controlled and monitored. Urinary calcium and markers of bone resorption were measured before bed rest and on bed rest days 5/6, 12/13, 19/20, and 26/27. Bone mineral content was assessed by dual-energy X-ray absorptiometry before and after bed rest. Data were analyzed by repeated-measures two-way analysis of variance. Pearson correlation coefficients were used to define the relationships between diet and markers of bone metabolism and to estimate heritability of markers. During bed rest, all markers of bone resorption and urinary calcium and phosphorus increased (P < 0.001); parathyroid hormone (P=0.06), bone-specific alkaline phosphatase (P=0.06), and 1,25-dihydroxyvitamin D (P = 0.09) tended to decrease. LBNP exercise tended to mitigate bone density loss. The ratio of dietary animal protein to potassium was positively correlated with urinary calcium excretion for all weeks of bed rest in the control group, but only during weeks I and 3 in the exercise group. Pre-bed rest data suggested that many markers of bone metabolism have strong genetic determinants. Treadmill exercise within LBNP had less of a protective effect on bone resorption during bed rest in women than previously published results had shown for its effect in men, but the same trends were observed for both sexes. Dietary acid load of these female subjects was significantly correlated with calcium excretion but not with other bone resorption markers. Published by Elsevier Inc. C1 NASA, Lyndon B Johnson Space Ctr, Human Adaptat & Countermeasures Off, Nutr Biochem Lab, Houston, TX 77058 USA. Univ N Texas, Hlth Sci Ctr, Dept Integrat Physiol, Ft Worth, TX 76104 USA. Wyle Labs, Houston, TX 77058 USA. Univ Calif San Diego, Med Ctr, Dept Orthopaed Surg, San Diego, CA 92103 USA. Univ Space Res Assoc, Houston, TX 77058 USA. RP Smith, SM (reprint author), NASA, Lyndon B Johnson Space Ctr, Human Adaptat & Countermeasures Off, Nutr Biochem Lab, Mail Code SK3,2101 NASA Pkwy, Houston, TX 77058 USA. EM scott.m.smith@nasa.gov FU NCRR NIH HHS [GCRC M01-RR00827, M01 RR000827, M01 RR000827-30S21064] NR 53 TC 39 Z9 40 U1 0 U2 3 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 8756-3282 J9 BONE JI Bone PD FEB PY 2007 VL 40 IS 2 BP 529 EP 537 DI 10.1016/j.bone.2006.09.014 PG 9 WC Endocrinology & Metabolism SC Endocrinology & Metabolism GA 129ZD UT WOS:000243767700033 PM 17070743 ER PT J AU Turner, DD Vogelmann, AM Austin, RT Barnard, JC Cady-Pereira, K Chiu, JC Clough, SA Flynn, C Khaiyer, MM Liljegren, J Johnson, K Lin, B Long, C Marshak, A Matrosov, SY McFarlane, SA Miller, M Min, Q Minnis, F O'Hirok, W Wang, Z Wiscombe, W AF Turner, D. D. Vogelmann, A. M. Austin, R. T. Barnard, J. C. Cady-Pereira, K. Chiu, J. C. Clough, S. A. Flynn, C. Khaiyer, M. M. Liljegren, J. Johnson, K. Lin, B. Long, C. Marshak, A. Matrosov, S. Y. McFarlane, S. A. Miller, M. Min, Q. Minnis, F. O'Hirok, W. Wang, Z. Wiscombe, W. TI Thin liquid water clouds - Their importance and our challenge SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article ID BOUNDARY-LAYER CLOUDS; MULTIPLE-SCATTERING LIDAR; GROUND-BASED MEASUREMENTS; IN-SITU; MICROWAVE RADIOMETER; OPTICAL-THICKNESS; RETRIEVALS; RADAR; SURFACE; MODELS AB Many of the clouds important to the Earth's energy balance, from the Tropics to the Arctic, contain small amounts of liquid water. Longwave and shortwave radiative fluxes are very sensitive to small perturbations of the cloud liquid water path (LWP), when the LWP is small (i.e., < 100 g m(-2); clouds with LWP less than this threshold will be referred to as "thin"). Thus, the radiative properties of these thin liquid water clouds must be well understood to capture them correctly in climate models. We review the importance of these thin clouds to the Earth's energy balance, and explain the difficulties in observing them. In particular, because these clouds are thin,, potentially mixed phase, and often broken (i.e., have large 3D variability), it is challenging to retrieve their microphysical properties accurately. We describe a retrieval algorithm intercomparison that was conducted to evaluate the issues involved. The intercomparison used data collected at the Atmospheric Radiation Measurement (ARM) Southern Great Plains (SGP) site and included 18 different algorithms to evaluate their retrieved LWP, optical depth, and effective radii. Surprisingly, evaluation of the simplest case, a single-layer meteorological, and transport and dispersion, modeling systems. Based on the experience gained in this project, it will be more straightforward to develop similar systems to protect other high-profile facilities against the accidental or intentional release of hazardous material into the atmosphere. (Page 167) overcast stratocumulus, revealed that huge discrepancies exist among the various techniques, even among different algorithms that are in the same general classification. This suggests that, despite considerable advances that have occurred in the field, much more work must be done, and we discuss potential avenues for future research. C1 Univ Wisconsin, Madison, WI 53706 USA. Brookhaven Natl Lab, Upton, NY 11973 USA. Colorado State Univ, Ft Collins, CO 80523 USA. Pacific NW Natl Lab, Richland, WA 99352 USA. Environm Res Inc, Lexington, MA USA. Univ Maryland Baltimore Cty, Baltimore, MD 21228 USA. AS&M, Hampton, VA USA. Argonne Natl Lab, Argonne, IL 60439 USA. NASA, Langley Res Ctr, Hampton, VA 23665 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Colorado, CIRES, Boulder, CO 80309 USA. NOAA, Earth Syst Res Lab, Boulder, CO 80309 USA. SUNY Albany, Albany, NY 12222 USA. Univ Calif Santa Barbara, Santa Barbara, CA 93106 USA. Univ Wyoming, Laramie, WY 82071 USA. Assoc Univ Inc, Brookhaven Natl Lab, Upton, NY 11973 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Turner, DD (reprint author), Univ Wisconsin, 1225 W Dayton St, Madison, WI 53706 USA. EM dturner@ssec.wisc.edu RI McFarlane, Sally/C-3944-2008; Wang, Zhien/F-4857-2011; Wiscombe, Warren/D-4665-2012; Chiu, Christine/E-5649-2013; Marshak, Alexander/D-5671-2012; Vogelmann, Andrew/M-8779-2014 OI Wiscombe, Warren/0000-0001-6844-9849; Chiu, Christine/0000-0002-8951-6913; Vogelmann, Andrew/0000-0003-1918-5423 NR 56 TC 106 Z9 107 U1 3 U2 17 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0003-0007 EI 1520-0477 J9 B AM METEOROL SOC JI Bull. Amer. Meteorol. Soc. PD FEB PY 2007 VL 88 IS 2 BP 177 EP + DI 10.1175/BAMS-88-2-177 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 145RG UT WOS:000244881600017 ER PT J AU Comstock, JM d'Entremont, R DeSlover, D Mace, GG Matrosov, SY McFarlane, SA Minnis, P Mitchell, D Sassen, K Shupe, MD Turner, DD Wang, Z AF Comstock, Jennifer M. d'Entremont, Robert DeSlover, Daniel Mace, Gerald G. Matrosov, Sergey Y. McFarlane, Sally A. Minnis, Patrick Mitchell, David Sassen, Kenneth Shupe, Matthew D. Turner, David D. Wang, Zhien TI An intercomparison of microphysical retrieval algorithms for upper-tropospheric ice clouds SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article ID DISCRETE-ORDINATE-METHOD; VISIBLE OPTICAL DEPTH; CIRRUS CLOUDS; WATER-CONTENT; RADAR MEASUREMENTS; RADIATIVE PROPERTIES; TROPICAL TROPOPAUSE; MILLIMETER RADAR; INFRARED RADIOMETER; COMBINED LIDAR AB The large horizontal extent, with its location in the cold upper troposphere, and ice composition make cirrus clouds important modulators of the Earth's radiation budget and climate. Cirrus cloud microphysical properties are difficult to measure and model because they are inhomogeneous in nature and their ice crystal size distribution and habit are not well characterized. Accurate retrievals of cloud properties are crucial for improving the representation of cloud-scale processes in large-scale models and for accurately predicting the Earth's future climate. A number of passive and active remote sensing retrieval algorithms exist for estimating the microphysical properties of upper-tropospheric clouds. We believe significant progress has been made in the evolution of these retrieval algorithms in the last decade; however, there is room for improvement. Members of the Atmospheric Radiation Measurement (ARM) program Cloud Properties Working Group are involved in an intercomparison of optical depth (tau) and ice water path in ice clouds retrieved using ground-based instruments. The goals of this intercomparison are to evaluate the accuracy of state-of-the-art algorithms, quantify the uncertainties, and make recommendations for their improvement. Currently, there are significant discrepancies among the algorithms for ice clouds with very small optical depths (tau < 0.3) and those with 1 < tau < 5. The good news is that for thin clouds (0.3 < tau < 1), the algorithms tend to converge. In this first stage of the intercomparison, we present results from a representative case study, compare the retrieved cloud properties with aircraft and satellite measurements, and perform a radiative closure experiment to begin gauging the accuracy of these retrieval algorithms. C1 Pacific NW Natl Lab, Richland, WA 99352 USA. Atmospher & Environm Res Inc, Lexington, MA USA. Univ Wisconsin, Madison, WI 53706 USA. Univ Utah, Salt Lake City, UT 84112 USA. NOAA, Earth Syst Res Lab, Cooperat Inst Res Environm Sci, Boulder, CO 80303 USA. NASA, Langley Res Ctr, Hampton, VA 23665 USA. Desert Res Inst, Reno, NV USA. Univ Alaska, Fairbanks, AK 99701 USA. Univ Wyoming, Laramie, WY 82071 USA. RP Comstock, JM (reprint author), Pacific NW Natl Lab, POB 999,MSIN K9-24, Richland, WA 99352 USA. EM jennifer.comstock@pnl.gov RI McFarlane, Sally/C-3944-2008; Wang, Zhien/F-4857-2011; Minnis, Patrick/G-1902-2010; Shupe, Matthew/F-8754-2011 OI Minnis, Patrick/0000-0002-4733-6148; Shupe, Matthew/0000-0002-0973-9982 NR 73 TC 52 Z9 53 U1 0 U2 13 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0003-0007 EI 1520-0477 J9 B AM METEOROL SOC JI Bull. Amer. Meteorol. Soc. PD FEB PY 2007 VL 88 IS 2 BP 191 EP + DI 10.1175/BAMS-88-2-191 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 145RG UT WOS:000244881600018 ER PT J AU Verlinde, J Harrington, JY McFarquhar, GM Yannuzzi, VT Avramov, A Greenberg, S Johnson, N Zhang, G Poellot, MR Mather, JH Turner, DD Eloranta, EW Zak, BD Prenni, AJ Daniel, JS Kok, GL Tobin, DC Holz, R Sassen, K Spangenberg, D Minnis, P Tooman, TP Ivey, MD Richardson, SJ Bahrmann, CP Shupe, M DeMott, PJ Heymsfield, AJ Schofield, R AF Verlinde, J. Harrington, J. Y. McFarquhar, G. M. Yannuzzi, V. T. Avramov, A. Greenberg, S. Johnson, N. Zhang, G. Poellot, M. R. Mather, J. H. Turner, D. D. Eloranta, E. W. Zak, B. D. Prenni, A. J. Daniel, J. S. Kok, G. L. Tobin, D. C. Holz, R. Sassen, K. Spangenberg, D. Minnis, P. Tooman, T. P. Ivey, M. D. Richardson, S. J. Bahrmann, C. P. Shupe, M. DeMott, P. J. Heymsfield, A. J. Schofield, R. TI The mixed-phase Arctic cloud experiment SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article ID POLAR PATHFINDER DATASET; RADIATION PROPERTIES; ATMOSPHERIC RADIATION; RESOLVING SIMULATIONS; BOUNDARY-LAYERS; STRATUS CLOUDS; DOPPLER RADAR; RECENT TRENDS; ICE CRYSTALS; BEAUFORT SEA AB The Mixed-Phase Arctic Cloud Experiment (M-PACE) was conducted from 27 September through 22 October 2004 over the Department of Energy's Atmospheric Radiation Measurement (ARM) Climate Research Facility (ACRF) on the North Slope of Alaska. The primary objectives were to collect a dataset suitable to study interactions between microphysics, dynamics, and radiative transfer in mixed-phase Arctic clouds, and to develop/evaluate cloud property retrievals from surface- and satellite-based remote sensing instruments. Observations taken during the 1977/98 Surface Heat and Energy Budget of the Arctic (SHEBA) experiment revealed that Arctic clouds frequently consist of one (or more) liquid layers precipitating ice. M-PACE sought to investigate the physical processes of these clouds by utilizing two aircraft (an in situ aircraft to characterize the microphysical properties of the clouds and a remote sensing aircraft to constraint the upwelling radiation) over the ACRF site on the North Slope of Alaska. The measurements successfully documented the microphysical structure of Arctic mixed-phase clouds, with multiple in situ profiles collected in both single- and multilayer clouds over two ground-based remote sensing sites. Liquid was found in clouds with cloud-top temperatures as cold as -30 degrees C, with the, coldest cloud-top temperature warmer than -40 degrees C sampled by the aircraft. Remote sensing instruments suggest that ice was present in low concentrations, mostly concentrated in precipitation shafts, although there are indications of light ice precipitation present below the optically thick single-layer clouds. The prevalence of liquid down to these low temperatures potentially could be explained by the relatively low measured ice nuclei concentrations. C1 Penn State Univ, Dept Meteorol, University Pk, PA 16802 USA. Univ Illinois, Urbana, IL 61801 USA. Univ N Dakota, Grand Forks, ND 58201 USA. Pacific NW Natl Lab, Richland, WA 99352 USA. Univ Wisconsin, Madison, WI 53706 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. Colorado State Univ, Ft Collins, CO 80523 USA. NOAA, Earth Syst Res Lab, Boulder, CO 80303 USA. Measurement Techol Inc, Boulder, CO USA. Univ Alaska, Fairbanks, AK 99701 USA. Serv & Mat Inc, Hampton, VA USA. NASA, Langley Res Ctr, Hampton, VA 23665 USA. Sandia Natl Labs, Livermore, CA 94550 USA. Natl Ctr Atmospher Res, Boulder, CO 80307 USA. Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80307 USA. NOAA, Earth Syst Res Lab, Boulder, CO 80303 USA. Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. RP Verlinde, J (reprint author), Penn State Univ, Dept Meteorol, 503 Walker Bldg, University Pk, PA 16802 USA. EM verlinde@meteo.psu.edu RI Schofield, Robyn/A-4062-2010; Prenni, Anthony/A-6820-2011; DeMott, Paul/C-4389-2011; Daniel, John/D-9324-2011; Heymsfield, Andrew/E-7340-2011; Minnis, Patrick/G-1902-2010; Shupe, Matthew/F-8754-2011; Johnson, Nathaniel/L-8045-2015; Manager, CSD Publications/B-2789-2015 OI Schofield, Robyn/0000-0002-4230-717X; DeMott, Paul/0000-0002-3719-1889; McFarquhar, Greg/0000-0003-0950-0135; Minnis, Patrick/0000-0002-4733-6148; Shupe, Matthew/0000-0002-0973-9982; Johnson, Nathaniel/0000-0003-4906-178X; NR 49 TC 143 Z9 143 U1 5 U2 39 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0003-0007 EI 1520-0477 J9 B AM METEOROL SOC JI Bull. Amer. Meteorol. Soc. PD FEB PY 2007 VL 88 IS 2 BP 205 EP 221 DI 10.1175/BAMS-88-2-205 PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 145RG UT WOS:000244881600019 ER PT J AU Predoi-Cross, A Brawley-Tremblay, S Povey, C Smith, MAH AF Predoi-Cross, Adriana Brawley-Tremblay, Shannon Povey, Chad Smith, Mary Ann H. TI Experimental air-broadened line parameters in the nu(2) band of CH3D SO CANADIAN JOURNAL OF PHYSICS LA English DT Article; Proceedings Paper CT 32nd Annual European Meeting on Atmospheric Studies by Optical Methods CY AUG 29-SEP 01, 2005 CL Univ Western Ontario, Phys & Astron Dept, London, CANADA HO Univ Western Ontario, Phys & Astron Dept ID DIODE-LASER MEASUREMENTS; INDUCED SHIFT COEFFICIENTS; PLANETARY-ATMOSPHERES; HALF-WIDTHS; D/H RATIO; (CH3D)-C-12; TEMPERATURES; METHANE; INTENSITIES; DEUTERIUM AB In this study, we report the first experimental measurements of air-broadening and air-induced pressure-shift coefficients for approximately 378 transitions in the nu(2) fundamental band of CH3D. These results were obtained from analysis of 17 room-temperature laboratory absorption spectra recorded at 0.0056 cm(-1) resolution using the McMath-Pierce Fourier transform spectrometer located on Kitt Peak, Ariz. Three absorption cells with path lengths of 10.2, 25, and 150 cm were used to record the spectra. The total sample pressures ranged from 0.129 x 10(-2) to 52.855 x 10(-2) atm with CH3D volume mixing ratios of approximately 0.0109 in air. The spectra were analyzed using a multispectrum nonlinear least-squares fitting technique. We report measurements for air pressure-broadening coefficients for transitions with quantum numbers as high as J'' = 20 and K = 15, where K'' = K' equivalent to K (for a parallel band). The measured air-broadening coefficients range from 0.0205 to 0.0835 cm(-1)atm(-1) at 296 K. All the measured pressure-shift coefficients are negative and are found to vary from about -0.0005 to -0.0080 cm(-1) atm(-1) at the temperature of the spectra. We have examined the dependence of the measured broadening and shift parameters on the J'', and K quantum numbers and also developed empirical expressions to describe the broadening coefficients in terms of m (m = -J'', J'', and J'' + 1 in the P-Q-, (Q)Q-, and R-Q-branch, respectively) and K. On average, the empirical expressions reproduce the measured broadening coefficients to within 4.4%. C1 Univ Lethbridge, Dept Phys, Lethbridge, AB T1K 3M4, Canada. NASA, Sci Directorate, Langley Res Ctr, Hampton, VA 23681 USA. RP Predoi-Cross, A (reprint author), Univ Lethbridge, Dept Phys, 4401 Univ Dr, Lethbridge, AB T1K 3M4, Canada. EM Adriana.predoicross@uleth.ca NR 26 TC 3 Z9 3 U1 0 U2 1 PU NATL RESEARCH COUNCIL CANADA-N R C RESEARCH PRESS PI OTTAWA PA BUILDING M 55, OTTAWA, ON K1A 0R6, CANADA SN 0008-4204 J9 CAN J PHYS JI Can. J. Phys. PD FEB PY 2007 VL 85 IS 2 BP 199 EP 218 DI 10.1139/P07-045 PG 20 WC Physics, Multidisciplinary SC Physics GA 163US UT WOS:000246189300011 ER PT J AU Ngo, Q Cassell, AM Radmilovic, V Li, J Krishnan, S Meyyappan, M Yang, CY AF Ngo, Quoc Cassell, Alan M. Radmilovic, Velimir Li, Jun Krishnan, S. Meyyappan, M. Yang, Cary. Y. TI Palladium catalyzed formation of carbon nanofibers by plasma enhanced chemical vapor deposition SO CARBON LA English DT Article ID INTERCONNECT APPLICATIONS; NANOTUBES; TRANSPORT; GROWTH; SEEDS AB A dc plasma enhanced chemical vapor deposition process is used to obtain vertically aligned carbon nanofibers (CNFs) from palladium catalysts using an ammonia-acetylene process gas mixture. Transmission electron microscopy is used to elucidate the microstructure of the as-grown fibers revealing different growth anomalies such as a new secondary growth phenomenon which we term hybrid tip growth. Also included in our analysis are conventional tip growth derived structures. In a few instances, the conventional tip growth derived structures possess elongated catalyst particles that impart small cone angles to the carbon nanofiber microstructure. Detailed microchemical analysis reveals that hybrid tip grown CNFs using thick Pd films are partially filled with Pd. Analysis of these growth phenomenon and implications for potential use as on-chip interconnects are discussed. (c) 2006 Elsevier Ltd. All rights reserved. C1 NASA, Ames Res Ctr, Ctr Nanotechnol, Moffett Field, CA 94035 USA. Santa Clara Univ, Ctr Nanostruct, Santa Clara, CA 95050 USA. Lawrence Berkeley Lab, Natl Ctr Electron Microscopy, Berkeley, CA 94720 USA. RP Cassell, AM (reprint author), NASA, Ames Res Ctr, Ctr Nanotechnol, M-S 229-1, Moffett Field, CA 94035 USA. EM acassell@mail.arc.nasa.gov RI Li, Jun/H-7771-2013 OI Li, Jun/0000-0002-3689-8946 NR 22 TC 15 Z9 15 U1 2 U2 10 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0008-6223 J9 CARBON JI Carbon PD FEB PY 2007 VL 45 IS 2 BP 424 EP 428 DI 10.1016/j.carbon.2006.08.019 PG 5 WC Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA 137CO UT WOS:000244270600027 ER PT J AU Bishop, JL Schiffman, P Murad, E Dyar, MD Drief, A Lane, MD AF Bishop, Janice L. Schiffman, Peter Murad, Enver Dyar, M. Darby Drief, Ahmed Lane, Melissa D. TI Characterization of alteration products in tephra from Haleakala, Maui: A visible-infrared spectroscopy, Mossbauer spectroscopy, XRD, EMPA and TEM study SO CLAYS AND CLAY MINERALS LA English DT Article DE altered tephra; alunite; EMPA; infrared Spectroscopy; jarosite; Mars; Mossbauer; SEM; smectite; solfataric alteration; XRD ID GUSEV CRATER; MERIDIANI-PLANUM; SPIRIT ROVER; MARTIAN DUST; EAST MAUI; MARS; VOLCANO; MINERALS; HAWAII; SULFATE AB Altered basaltic tephra from Haleakala, Maui, are characterized using multiple techniques in order to identify the minerals formed under a variety of conditions and to understand the soil formation processes here. We collected samples that are representative of typical bulk weathered material in the crater, as well as solfataric alteration in a hydrothermal environment. For this study X-ray diffraction, electron probe microanalysis, scanning electron microscopy and transmission electron microscopy are coupled with spectroscopic techniques including Mossbauer, visible-infrared reflectance, transmission infrared, and thermal infrared emission spectroscopies to analyze these samples. The unaltered tephra are composed of feldspar, glass, pyroxene and olivine. Observed alteration products include Fe oxides, phyllosilicates and sulfates, as well as SAED amorphous Al-Si-bearing material. These samples are potential analogs for altered volcanic material on Mars as the pedogenic influences and contact with plants and animals are minimal. Results from this study may help to determine spectral signatures of these samples that could be used for identification on Mars of the minerals observed here. C1 SETI Inst, Mountain View, CA 94043 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ Calif Davis, Dept Geol, Davis, CA 95616 USA. Bayer Landesamt Umwelt, D-95603 Marktredwitz, Germany. Mt Holyoke Coll, S Hadley, MA 01075 USA. Clorox Co, Pleasanton, CA 94588 USA. Planetary Sci Inst, Tucson, AZ 85719 USA. RP Bishop, JL (reprint author), SETI Inst, 515 N Whisman Rd, Mountain View, CA 94043 USA. EM jbishop@arc.nasa.gov NR 42 TC 29 Z9 29 U1 2 U2 14 PU CLAY MINERALS SOC PI CHANTILLY PA 3635 CONCORDE PKWY, STE 500, CHANTILLY, VA 20151-1125 USA SN 0009-8604 EI 1552-8367 J9 CLAY CLAY MINER JI Clay Clay Min. PD FEB PY 2007 VL 55 IS 1 BP 1 EP 17 DI 10.1346/CCMN.2007.0550101 PG 17 WC Chemistry, Physical; Geosciences, Multidisciplinary; Mineralogy; Soil Science SC Chemistry; Geology; Mineralogy; Agriculture GA 148KG UT WOS:000245072700001 ER PT J AU Potter, C Klooster, S Hiatt, S Fladeland, M Genovese, V Gross, P AF Potter, Christopher Klooster, Steven Hiatt, Seth Fladeland, Matthew Genovese, Vanessa Gross, Peggy TI Satellite-derived estimates of potential carbon sequestration through afforestation of agricultural lands in the United States SO CLIMATIC CHANGE LA English DT Article ID FOSSIL-FUEL SUBSTITUTION; FORESTS; RESPIRATION; BIOMASS; MODEL; SINKS; MODIS AB Afforestation of marginal agricultural lands represents a promising option for carbon sequestration in terrestrial ecosystems. An ecosystem carbon model was used to generate new national maps of annual net primary production (NPP), one each for continuous land covers of 'forest', 'crop', and 'rangeland' over the entire U. S. continental area. Direct inputs of satellite "greenness" data from the Advanced Very High Resolution Radiometer (AVHRR) sensor into the NASA-CASA carbon model at 8-km spatial resolution were used to estimate spatial variability in monthly NPP and potential biomass accumulation rates in a uniquely detailed manner. The model predictions of regrowth forest production lead to a conservative national projection of 0.3 Pg C as potential carbon stored each year on relatively low-production crop or rangeland areas. On a regional level, the top five states for total crop afforestation potential were: Texas, Minnesota, Iowa, Illinois, and Missouri, whereas the top five states for total rangeland afforestation potential are: Texas, California, Montana, New Mexico, and Colorado. Afforestation at this level of intensity has the capacity to offset at least one-fifth of annual fossil fuel emission of carbon in the United States. These projected afforestation carbon gains also match or exceed recent estimates of the annual sink for atmospheric CO2 in currently forested area of the country. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Calif State Univ Monterey Bay, Seaside, CA USA. San Jose State Univ & Educ Associates, Moffett Field, CA USA. RP Potter, C (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. EM cpotter@mail.arc.nasa.gov RI daorui, han/G-3767-2011 NR 30 TC 18 Z9 20 U1 1 U2 18 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0165-0009 J9 CLIMATIC CHANGE JI Clim. Change PD FEB PY 2007 VL 80 IS 3-4 BP 323 EP 336 DI 10.1007/s10584-006-9109-3 PG 14 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA 130MI UT WOS:000243803300009 ER PT J AU Nakano, A Kalia, RK Nomura, K Sharma, A Vashishta, P Shimojo, F van Duin, ACT Goddard, WA Biswas, R Srivastava, D AF Nakano, Aiichiro Kalia, Rajiv K. Nomura, Ken-ichi Sharma, Ashish Vashishta, Priya Shimojo, Fuyuki van Duin, Adri C. T. Goddard, William A. Biswas, Rupak Srivastava, Deepak TI A divide-and-conquer/cellular-decomposition framework for million-to-billion atom simulations of chemical reactions SO COMPUTATIONAL MATERIALS SCIENCE LA English DT Article DE molecular dynamics; reactive force field; quantum mechanics; density functional theory; parallel computing ID DENSITY-FUNCTIONAL-THEORY; MOLECULAR-DYNAMICS SIMULATION; ELECTRONIC-STRUCTURE METHODS; REAL-SPACE GRIDS; PARALLEL COMPUTERS; ALGORITHM; SCALABILITY; PERFORMANCE; CHEMISTRY; PATHWAYS AB To enable large-scale atomistic simulations of material processes involving chemical reactions, we have designed linear-scaling molecular dynamics (MD) algorithms based on an embedded divide-and-conquer (EDC) framework: first principles-based fast reactive force-field (F-ReaxFF) MD; and quantum-mechanical MD in the framework of the density functional theory (DFT) on adaptive multigrids. To map these O(N) algorithms onto parallel computers with deep memory hierarchies, we have developed a tunable hierarchical cellular-decomposition (THCD) framework, which achieves performance tunability through a hierarchy of parameterized cell data/computation structures and adaptive load balancing through wavelet-based computational-space decomposition. Benchmark tests on 1920 Itanium2 processors of the NASA Columbia supercomputer have achieved unprecedented scales of quantum-mechanically accurate and well validated, chemically reactive atomistic simulations-0.56 billion-atom F-ReaxFF MD and 1.4 million-atom (0.12 trillion grid points) EDC-DFT MD-in addition to 18.9 billion-atom non reactive space-time multiresolution MD. The EDC and THCD frameworks expose maximal data localities, and consequently the isogranular parallel efficiency on 1920 processors is as high as 0.953. Chemically reactive MD simulations have been applied to shock-initiated detonation of energetic materials and stress-induced bond breaking in ceramics in corrosive environments. (c) 2006 Elsevier B.V. All rights reserved. C1 Univ So Calif, Dept Phys & Astron, Dept Comp Sci, Collaborat Adv Comp & Simulat,Dept Chem Engn & Ma, Los Angeles, CA 90089 USA. Kumamoto Univ, Dept Phys, Kumamoto 8608555, Japan. CALTECH, Mat & Proc Simulat Ctr, Div Chem & Chem Engn, Pasadena, CA 91125 USA. NASA, Ames Res Ctr, NASA Adv Supercomp, Moffett Field, CA 94035 USA. RP Nakano, A (reprint author), Univ So Calif, Dept Phys & Astron, Dept Comp Sci, Collaborat Adv Comp & Simulat,Dept Chem Engn & Ma, Los Angeles, CA 90089 USA. EM anakano@usc.edu NR 60 TC 59 Z9 61 U1 8 U2 31 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0927-0256 EI 1879-0801 J9 COMP MATER SCI JI Comput. Mater. Sci. PD FEB PY 2007 VL 38 IS 4 BP 642 EP 652 DI 10.1016/j.commatsci.2006.04.012 PG 11 WC Materials Science, Multidisciplinary SC Materials Science GA 138LO UT WOS:000244364300011 ER PT J AU Beach, J Ning, JF Khoobehi, B AF Beach, James Ning, Jinfeng Khoobehi, Bahram TI Oxygen saturation in optic nerve head structures by hyperspectral image analysis SO CURRENT EYE RESEARCH LA English DT Article DE hyperspectral imaging; optic nerve head; oxygen saturation-; retinal imaging ID RETINAL-VESSELS; BLOOD-FLOW; SPECTROSCOPIC ASSESSMENT; TENSION; CONSUMPTION; RETINOPATHY; OXIMETRY; TISSUE; CAT; INCREASES AB Purpose: A method is presented for the calculation and visualization of percent blood oxygen saturation from specific tissue structures in hyperspectral images of the optic nerve head (ONH). Methods: Trans-pupillary images of the primate optic nerve head and overlying retinal blood vessels were obtained with a hyperspectral imaging (HSI) system attached to a fundus camera. Images were recorded during normal blood flow and after partially interrupting flow to the ONH and retinal circulation by elevation of the intraocular pressure (IOP) from 10 mmHg to 55 mmHg in steps. Percent oxygen saturation was calculated from groups of pixels associated with separate tissue structures, using a linear least-squares curve fit of the recorded hemoglobin spectrum to reference spectra obtained from fully oxygenated and deoxygenated red cell suspensions. Color maps of saturation were obtained from a new algorithm that enables comparison of oxygen saturation from large vessels and tissue areas in hyperspectral images. Results: Percent saturation in retinal vessels and from the average over ONH structures (IOP = 10 mmHg) was (mean SE): artery 81.8 +/- 0.4%, vein 42.6 +/- 0.9%, average ONH 68.3 +/- 0.4%. Raising IOP from 10 mmHg to 55 mmHg for 5 min caused blood oxygen saturation to decrease (mean +/- SE): artery 46.1 +/- 6.2%, vein 36.1 +/- 1.6%, average ONH 41.9 +/- 1.6%. The temporal cup showed the highest saturation at low and high IOP (77.3 +/- 1.0% and 60.1 +/- 4.0%) and the least reduction in saturation at high IOP (22.3%) compared with that of the average ONH (38.6%). A linear relationship was found between saturation indices obtained from the algorithm and percent saturation values obtained by spectral curve fits to calibrated red cell samples. Conclusions: Percent oxygen saturation was determined from hyperspectral images of the ONH tissue and retinal vessels overlying the ONH at normal and elevated IOP. Pressure elevation was shown to reduce blood oxygen saturation in vessels and ONH structures, with the smallest reduction in the ONH observed in the temporal cup. IOP-induced saturation changes were visualized in color maps using an algorithm that follows saturation-dependent changes in the blood spectrum and blood volume differences across tissue. Reduced arterial saturation at high IOP may have resulted from a flow-dependent mechanism. C1 Stennis Space Ctr, Inst Technol Dev, Bay St Louis, MS USA. Louisiana State Univ, Hlth Sci Ctr, Dept Ophthalmol, New Orleans, LA USA. RP Beach, J (reprint author), Univ Iceland, Dept Elect & Comp Engn, Reykjavik, Iceland. EM eadeae@gmail.com FU NEI NIH HHS [R03 EY 014872, R43 EY 014776, P30 EY 02377] NR 40 TC 29 Z9 30 U1 1 U2 3 PU TAYLOR & FRANCIS INC PI PHILADELPHIA PA 325 CHESTNUT ST, SUITE 800, PHILADELPHIA, PA 19106 USA SN 0271-3683 J9 CURR EYE RES JI Curr. Eye Res. PD FEB PY 2007 VL 32 IS 2 BP 161 EP 170 DI 10.1080/02713680601139192 PG 10 WC Ophthalmology SC Ophthalmology GA 142YA UT WOS:000244686000010 PM 17364749 ER PT J AU Saber, HH El-Genk, MS Caillat, T AF Saber, Hamed H. El-Genk, Mohamed S. Caillat, Thierry TI Tests results of skutterudite based thermoelectric unicouples SO ENERGY CONVERSION AND MANAGEMENT LA English DT Article DE skutterudite; thermoelectric conversion; metallic coating; performance tests; space power ID RADIOISOTOPE POWER-SYSTEMS; HEATER UNITS; FUEL COMPACT; PERFORMANCE; PARTICLES AB Tests were performed of skutterudite based unicouples with (MAY-04) and without (MAR-03) metallic coating on the legs near the hot junction to quantify the effect on reducing performance degradation with operation time. The p-legs in the unicouples were made of CeFe3.5Co0.5Sb12 and the n-legs of CoSb3. The MAY-04 test was performed in vacuum (similar to 9 X 10(-7) torr) for similar to 2000 h at hot and cold junction temperatures of 892.1 +/- 11.9 K and 316.1 +/- 5.5 K, respectively, while the MAR-03 test was performed in argon cover gas (0.051-0.068 MPa) at 972.61 +/- 10.0 K and 301.1 +/- 5.1 K, respectively. The argon cover gas decreased antimony loss from the legs in the MAR-03 test, but marked degradation in performance occurred over time. Conversely, the metallic coating in the MAY-04 test was very effective in reducing performance degradation of the unicouple. Because the cross sectional areas of the legs in MAY-04 were larger than those in MAR-03, the measured electrical power of the former is much higher than that of the latter, but the Beginning of Test (BOT) open circuit voltages, V-oc (204.2 mV) for both unicouples were almost the same. The peak electrical power of the MAY-04 unicouple decreased 12.35% from 1.62 W-e at BOT to 1.42 W-e, after similar to 2000 h of testing, while that of the MAR-03 unicouple decreased 25.37% from 0.67 to 0.5 W-e after 261 h of testing at the above temperatures. The estimated peak efficiency of the MAY-04 unicouple, shortly after BOT (10.65%), was only similar to 0.37% points lower than the theoretical value, calculated assuming zero side heat losses and zero contact resistance per leg. (c) 2006 Elsevier Ltd. All rights reserved. C1 Univ New Mexico, Inst Space & Nucl Power Studies, Dept Chem & Nucl Engn, Albuquerque, NM USA. CALTECH, Jet Prop Lab, Pasadena, CA USA. RP El-Genk, MS (reprint author), Univ New Mexico, Inst Space & Nucl Power Studies, Dept Chem & Nucl Engn, Albuquerque, NM USA. EM mgenk@unm.edu NR 18 TC 25 Z9 25 U1 1 U2 16 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0196-8904 J9 ENERG CONVERS MANAGE JI Energy Conv. Manag. PD FEB PY 2007 VL 48 IS 2 BP 555 EP 567 DI 10.1016/j.enconman.2006.06.008 PG 13 WC Thermodynamics; Energy & Fuels; Mechanics SC Thermodynamics; Energy & Fuels; Mechanics GA 130KW UT WOS:000243799500026 ER PT J AU Pointing, SB Warren-Rhodes, KA Lacap, DC Rhodes, KL Mckay, CP AF Pointing, Stephen B. Warren-Rhodes, Kimberley A. Lacap, Donnabella C. Rhodes, Kevin L. Mckay, Christopher P. TI Hypolithic community shifts occur as a result of liquid water availability along environmental gradients in China's hot and cold hyperarid deserts SO ENVIRONMENTAL MICROBIOLOGY LA English DT Article ID MICROBIAL DIVERSITY; CYANOBACTERIA; BACTERIA; SOIL; CRUSTS; DESERTIFICATION; BIODIVERSITY; CHLOROFLEXUS; DESICCATION; POPULATIONS AB Hypolithic cyanobacterial communities occur in hot and cold hyperarid environments but the physical factors determining their diversity are not well understood. Here we report hypolithic diversity and colonization of a common quartz substrate at several hyperarid locations in the ancient deserts of north-western China, that experience varying mean annual temperature, rainfall and concomitant availability of liquid water in soil. Microscopy and enrichment culture resulted only in Chroococcidiopsis morphotypes which were ubiquitous, but community phylogenetic analysis revealed considerable cyanobacterial and heterotrophic bacterial diversity. Species Richness and Shannon's Diversity Index displayed a significant positive linear correlation with availability of liquid water but not temperature or rainfall alone. Several taxonomic groups occurred only in specific climatically defined locations, while for Chroococcidiopsis, Deinococcus and Phormidium location specific lineages within these genera were also evident. Multivariate analysis was used to illustrate pronounced community shifts due to liquid water availability, although these did not significantly affect the predicted functional relationships within any given assemblage in either hot or cold, wet or dry hyperarid deserts. This study clearly demonstrates that availability of liquid water, rather than temperature or rainfall per se is the key determinant of hypolithic diversity in hyperarid locations, and furthermore that functionally similar yet taxonomically distinct communities occur, characterized by the presence of taxa that are specific to defined levels of aridity. C1 Univ Hong Kong, Sch Biol Sci, Hong Kong, Hong Kong, Peoples R China. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ Hawaii, Dept Agr Forestry & Nat Resource Management, Hilo, HI 96720 USA. RP Pointing, SB (reprint author), Univ Hong Kong, Sch Biol Sci, Pokfulam Rd, Hong Kong, Hong Kong, Peoples R China. EM pointing@hku.hk RI Pointing, Stephen/D-3119-2009 NR 46 TC 53 Z9 54 U1 1 U2 16 PU WILEY-BLACKWELL PUBLISHING, INC PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 1462-2912 J9 ENVIRON MICROBIOL JI Environ. Microbiol. PD FEB PY 2007 VL 9 IS 2 BP 414 EP 424 DI 10.1111/j.1462-2920.2006.01153.x PG 11 WC Microbiology SC Microbiology GA 124OF UT WOS:000243376800013 PM 17222139 ER PT J AU Valle-Levinson, A Blanco, JL Frangopulos, M AF Valle-Levinson, Arnoldo Blanco, Jose Luis Frangopulos, Maximo TI Depth-dependent overtides from internal tide reflection in a Glacial Fjord SO ESTUARIES AND COASTS LA English DT Article ID WAVES; INLET; TOPOGRAPHY; ESTUARIES; BARRIER; CHANNEL; OCEAN; FLOW AB Observations of current velocity profiles and hydrography over and near a tall sill in a Chilean glacial fjord are used to illustrate the interactions between barotropic and baroclinic tides. The character of the barotropic tide in the glacial fjord is mixed with semidiurnal dominance. The ratio of sill height to water column depth at the study site is ca. 0.95. Water column stratification appeared only in the upper 5 in of the water column. Current velocity variations in the stratified surface layer were quite different to those underneath. Below the pycnocline, nonlinear interactions between semidiurnal M-2 and diurnal K-1 oscillations yielded a third-diurnal distortion MK3. Most interesting, surface layer currents were distorted by the superposition of semidiurnal M-2 and sixthdiurnal M-6 oscillations. The oscillations with M-6 variability were identified, through wave superposition approaches, as reflected internal tides linked to M-2 tidal variations. This was confirmed by theoretical results of stratified barotropic tidal flows interacting with abrupt bathymetry. Under the predominantly tidally mixed regime of the study area, the distortion to surface currents caused by the reflected wave was nearly symmetric during the large tidal ranges of the diurnal cycle. Nearly symmetric distortions resulted as the phase lag between incident and reflected wave-induced currents was small (reflected currents developing a few minutes after maximum tidal flows). During the small ranges of the diurnal cycle, distortions were asymmetrical because of the relatively larger phase lags of the reflected signal (reflected currents developing tens of minutes after maximum tidal flows). C1 Univ Florida, Gainesville, FL 32611 USA. NASA, Wallops Flight Facil, Observat Sci Branch, Wallops Isl, VA 23337 USA. Fdn Ctr Estudios Cuaternario Fuego Patagonia, CEQUA, Punta Arenas, Chile. RP Valle-Levinson, A (reprint author), Univ Florida, 365 Weil Hall, Gainesville, FL 32611 USA. EM arnoldo@ufl.edu NR 19 TC 6 Z9 6 U1 1 U2 4 PU ESTUARINE RESEARCH FEDERATION PI PORT REPUBLIC PA 2018 DAFFODIL, PO BOX 510, PORT REPUBLIC, MD 20676 USA SN 1559-2723 J9 ESTUAR COAST JI Estuaries Coasts PD FEB PY 2007 VL 30 IS 1 BP 127 EP 136 PG 10 WC Environmental Sciences; Marine & Freshwater Biology SC Environmental Sciences & Ecology; Marine & Freshwater Biology GA 149GD UT WOS:000245134200013 ER PT J AU Hatamleh, O Lyons, J Forman, R AF Hatamleh, Omar Lyons, Jed Forman, Royce TI Laser peening and shot peening effects on fatigue life and surface roughness of friction stir welded 7075-T7351 aluminum SO FATIGUE & FRACTURE OF ENGINEERING MATERIALS & STRUCTURES LA English DT Article DE fatigue; friction stir welding; laser peening; shot peening ID RESIDUAL-STRESS RELAXATION; CRACK GROWTH; ALLOYS; MICROSTRUCTURE; BEHAVIOR; SPEED AB The effects of laser peening, shot peening, and a combination of both on the fatigue life of Friction Stir Welds (FSW) was investigated. The fatigue samples consisted of dog bone specimens and the loading was applied in a direction perpendicular to the weld direction. Several laser peening (LP) conditions with different intensities, durations, and peening orders were tested in order to obtain the optimum peening parameters. The surface roughness resulting from various peening techniques was assessed and characterized. The results indicate a significant increase in fatigue life using LP compared to shot peening when tested on their native welded specimens. C1 NASA, Lyndon B Johnson Space Ctr, Struct & Dynam Branch, Houston, TX 77058 USA. NASA, Lyndon B Johnson Space Ctr, Mat & Proc Branch, Houston, TX 77058 USA. Univ S Carolina, Dept Mech Engn, Columbia, SC 29208 USA. RP Hatamleh, O (reprint author), NASA, Lyndon B Johnson Space Ctr, Struct & Dynam Branch, Houston, TX 77058 USA. EM omar.hatamleh-1@nasa.gov NR 38 TC 23 Z9 23 U1 3 U2 24 PU BLACKWELL PUBLISHING PI OXFORD PA 9600 GARSINGTON RD, OXFORD OX4 2DQ, OXON, ENGLAND SN 8756-758X J9 FATIGUE FRACT ENG M JI Fatigue Fract. Eng. Mater. Struct. PD FEB PY 2007 VL 30 IS 2 BP 115 EP 130 DI 10.1111/j.1460-2695.2006.01093.x PG 16 WC Engineering, Mechanical; Materials Science, Multidisciplinary SC Engineering; Materials Science GA 132XQ UT WOS:000243976600005 ER PT J AU Yung, PT Shafaat, HS Connon, SA Ponce, A AF Yung, Pun To Shafaat, Hannah S. Connon, Stephanie A. Ponce, Adrian TI Quantification of viable endospores from a Greenland ice core SO FEMS MICROBIOLOGY ECOLOGY LA English DT Article; Proceedings Paper CT International Conference on Alpine and Polar Microbiology CY MAR 27-31, 2006 CL Innsbruck, AUSTRIA SP Inst Microbiol, Leopold Franzens Univ, Free Univ Bozen Bolzano, Canadian Studies Ctr, LEU, FEMS DE viability; endospore longevity; bacterial spore; Greenland; terbium; dipicolinic acid ID BACTERIAL-SPORES; GLACIER ICE; BACILLUS-SUBTILIS; MICROORGANISMS; GERMINATION; SURVIVAL; IDENTIFICATION; ENVIRONMENTS; EXOBIOLOGY; PANSPERMIA AB Endospores (i.e., bacterial spores) embedded in polar ices present an opportunity to investigate the most durable form of life in an ideal medium for maintaining long-term viability. However, little is known about the endospore distribution and viability in polar ices. We have determined germinable endospore concentrations of bacterial spores capable of germination in a Greenland ice core (GISP2 94 m, ID# G2-271) using two complementary endospore viability assays (EVA), recently developed in our laboratory. These assays are based on bulk spectroscopic analysis (i.e., spectroEVA), and direct microscopic enumeration (i.e., microEVA) of ice core concentrates. Both assays detect dipicolinic acid (DPA) release during L-alanine induced germination via terbium ion (Tb3+)-DPA luminescence. Using spectroEVA, the germinable and total bacterial spore concentrations were found to be 295 +/- 19 spores mL(-1) and 369 +/- 36 spores mL(-1), respectively, (i.e., 80% of the endospores were capable of germination). Using microEVA, the germinating endospore concentration was found to be 27 +/- 2 spores mL(-1). The total cell concentration, as determined by DAPI stain fluorescence microscopy, was 7.0 x 10(3)+/- 6.7 x 10(2) cells mL(-1). Culturing attempts yielded 2 CFU mL(-1) (4 degrees C). We conclude that endospores capable of germination in the GISP2 ice cores are readily determined using novel endospore viability assays. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Ponce, A (reprint author), CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. EM ponce@caltech.edu RI Connon, Stephanie/K-1959-2012 NR 44 TC 27 Z9 28 U1 0 U2 6 PU BLACKWELL PUBLISHING PI OXFORD PA 9600 GARSINGTON RD, OXFORD OX4 2DQ, OXON, ENGLAND SN 0168-6496 J9 FEMS MICROBIOL ECOL JI FEMS Microbiol. Ecol. PD FEB PY 2007 VL 59 IS 2 BP 300 EP 306 DI 10.1111/j.1574-6941.2006.00218.x PG 7 WC Microbiology SC Microbiology GA 126IO UT WOS:000243506800009 PM 17313579 ER PT J AU Rodrigues, DF Tiedje, JM AF Rodrigues, Debora Frigi Tiedje, James M. TI Multi-locus real-time PCR for quantitation of bacteria in the environment reveals Exiguobacterium to be prevalent in permafrost SO FEMS MICROBIOLOGY ECOLOGY LA English DT Article; Proceedings Paper CT International Conference on Alpine and Polar Microbiology CY MAR 27-31, 2006 CL Innsbruck, AUSTRIA SP Inst Microbiol, Leopold Franzens Univ, Free Univ Bozen Bolzano, Canadian Studies Ctr, LEU, FEMS DE real-time PCR; Exiguobacterium spp; rpoB; gyrB; Siberian permafrost ID GENE RPOB SEQUENCES; OPERON COPY NUMBER; RIBOSOMAL-RNA; RT-PCR; SP-NOV; DNA; QUANTIFICATION; ENUMERATION; STRATEGIES; SEDIMENTS AB We developed a multi-locus quantitative PCR approach to minimize problems of precision, sensitivity and primer specificity for quantifying a targeted microbial group in nature. This approach also avoids a systematic error in population quantitation when 16S rRNA genes are used because of copy number heterogeneity. Specific primers were designed to assess the abundance of psychrotrophic and mesophilic Exiguobacterium spp. that excluded the thermophilic members of the genus. The chosen primers targeted genes for DNA gyrase B (gyrB), the beta subunit of the RNA polymerase gene (rpoB) and a hypothetical gene so far found only in this group. The results demonstrate that the multiple primer approach provides a more reliable estimate of population density; that the targeted Exiguobacterium group is found at a median density of 50 000 gene copies per mu g of total community DNA in 27 of 29 permafrost soils but was found in only one of the four temperate and tropical soils tested. C1 Michigan State Univ, NASA, Astrobiol Inst, E Lansing, MI 48824 USA. Michigan State Univ, Ctr Microbial Ecol, E Lansing, MI 48824 USA. RP Rodrigues, DF (reprint author), Michigan State Univ, NASA, Astrobiol Inst, 540 Plant & Soil Sci Bldg, E Lansing, MI 48824 USA. EM rodri257@msu.edu RI Rodrigues, Debora/H-4375-2012; OI Rodrigues, Debora/0000-0002-3124-1443 NR 32 TC 18 Z9 19 U1 2 U2 12 PU BLACKWELL PUBLISHING PI OXFORD PA 9600 GARSINGTON RD, OXFORD OX4 2DQ, OXON, ENGLAND SN 0168-6496 J9 FEMS MICROBIOL ECOL JI FEMS Microbiol. Ecol. PD FEB PY 2007 VL 59 IS 2 BP 489 EP 499 DI 10.1111/j.1574-6941.2006.00233.x PG 11 WC Microbiology SC Microbiology GA 126IO UT WOS:000243506800026 PM 17156079 ER PT J AU Steven, B Briggs, G McKay, CP Pollard, WH Greer, CW Whyte, LG AF Steven, Blaire Briggs, Geoffrey McKay, Chris P. Pollard, Wayne H. Greer, Charles W. Whyte, Lyle G. TI Characterization of the microbial diversity in a permafrost sample from the Canadian high Arctic using culture-dependent and culture-independent methods SO FEMS MICROBIOLOGY ECOLOGY LA English DT Article; Proceedings Paper CT International Conference on Alpine and Polar Microbiology CY MAR 27-31, 2006 CL Innsbruck, AUSTRIA SP Inst Microbiol, Leopold Franzens Univ, Free Univ Bozen Bolzano, Canadian Studies Ctr, LEU, FEMS DE permafrost; microbial diversity; culture-independent; culture-dependent ID SIBERIAN PERMAFROST; ENVIRONMENTAL-SAMPLES; BACTERIAL COMMUNITY; DNA EXTRACTION; POLAR-REGIONS; ICE CORE; MICROORGANISMS; SOIL; PSYCHROPHILES; PERSISTENCE AB A combination of culture-dependent and culture-independent methodologies (Bacteria and Archaea 16S rRNA gene clone library analyses) was used to determine the microbial diversity present within a geographically distinct high Arctic permafrost sample. Culturable Bacteria isolates, identified by 16S rRNA gene sequencing, belonged to the phyla Firmicutes, Actinobacteria and Proteobacteria with spore-forming Firmicutes being the most abundant; the majority of the isolates (19/23) were psychrotolerant, some (11/23) were halotolerant, and three isolates grew at -5 degrees C. A Bacteria 16S rRNA gene library containing 101 clones was composed of 42 phylotypes related to diverse phylogenetic groups including the Actinobacteria, Proteobacteria, Firmicutes, Cytophaga - Flavobacteria - Bacteroides, Planctomyces and Gemmatimonadetes; the bacterial 16S rRNA gene phylotypes were dominated by Actinobacteria- and Proteobacteria-related sequences. An Archaea 16S rRNA gene clone library containing 56 clones was made up of 11 phylotypes and contained sequences related to both of the major Archaea domains (Euryarchaeota and Crenarchaeota); the majority of sequences in the Archaea library were related to halophilic Archaea. Characterization of the microbial diversity existing within permafrost environments is important as it will lead to a better understanding of how microorganisms function and survive in such extreme cryoenvironments. C1 McGill Univ, Dept Nat Resource Sci, Ste Anne De Bellevue, PQ H9X 3V9, Canada. NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA. McGill Univ, Dept Geog, Montreal, PQ H3A 2T5, Canada. Natl Res Council Canada, Biotechnol Res Inst, Montreal, PQ H4P 2R2, Canada. RP Whyte, LG (reprint author), McGill Univ, Dept Nat Resource Sci, 21 111 Lakeshore Rd, Ste Anne De Bellevue, PQ H9X 3V9, Canada. EM lyle.white@mcgill.ca RI Steven, Blaire/E-5295-2012 OI Steven, Blaire/0000-0001-5940-2432 NR 58 TC 117 Z9 136 U1 7 U2 36 PU BLACKWELL PUBLISHING PI OXFORD PA 9600 GARSINGTON RD, OXFORD OX4 2DQ, OXON, ENGLAND SN 0168-6496 J9 FEMS MICROBIOL ECOL JI FEMS Microbiol. Ecol. PD FEB PY 2007 VL 59 IS 2 BP 513 EP 523 DI 10.1111/j.1574-6941.2006.00247.x PG 11 WC Microbiology SC Microbiology GA 126IO UT WOS:000243506800028 PM 17313587 ER PT J AU Courtney, DL Severin, KP AF Courtney, Dean L. Severin, Kenneth P. TI Validation of otolith increment daily periodicity in captive juvenile sablefish (Anoplopoma fimbria) experimentally immersed in strontium chloride (SrCl2) SO FISHERIES RESEARCH LA English DT Article DE sablefish; otolith microstructure; daily age; accuracy; precision ID GROWTH; AGE; ATLANTIC; PISCES; MARK AB We used a chemical marking experiment to validate the daily periodicity of otolith increment deposition in juvenile sablefish, Anoplopoma fimbria. The sagittal otoliths of 26 live juvenile sablefish were marked twice by immersion in saltwater baths containing elevated levels of strontium chloride (SrCl2) during June-August of their first year of life (age 0). The number of otolith increments detected between strontium bands from three readings (median 15-20) was compared to the number of days between marking events (15-17 days). Median discrepancies between otolith increment counts and days between strontium bands were small (mean 1.1, S.E. 0.81, n = 20) and suggest that otolith increment counts from age 0 juvenile sablefish may provide a useful proxy for daily age. However, median discrepancies in June (mean 4.7, S.E. 0.65, n = 9 otoliths) were significantly (*P <= 0.05) higher than those in July (mean -1.8, S.E. 0.40, n = 6) and August (mean -1.8, S.E. 0.66, n = 5). Increment banding patterns were more difficult to identify in otoliths marked in June (mean sablefish size 84.9 mm FL) because of changes in the structure of the sagittae associated with the formation of accessory primordia. (c) 2006 Elsevier B.V. All rights reserved. C1 Natl Marine Fisheries Serv, NOAA, Auke Bay Lab, Juneau, AK 99801 USA. Univ Alaska Fairbanks, Adv Instrumentat Lab, Fairbanks, AK 99775 USA. RP Courtney, DL (reprint author), Natl Marine Fisheries Serv, NOAA, Auke Bay Lab, 11305 Glacier Highway, Juneau, AK 99801 USA. EM dean.courtney@noaa.gov NR 32 TC 2 Z9 3 U1 0 U2 11 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0165-7836 J9 FISH RES JI Fish Res. PD FEB PY 2007 VL 83 IS 2-3 BP 246 EP 252 DI 10.1016/j.fishres.2006.10.013 PG 7 WC Fisheries SC Fisheries GA 131DA UT WOS:000243847200013 ER PT J AU Smith, AM Murray, T Nicholls, KW Makinson, K Aoalgeirsdottir, G Behar, AE Vaughan, DG AF Smith, A. M. Murray, T. Nicholls, K. W. Makinson, K. Aoalgeirsdottir, G. Behar, A. E. Vaughan, D. G. TI Rapid erosion, drumlin formation, and changing hydrology beneath an Antarctic ice stream SO GEOLOGY LA English DT Article DE subglacial environment; ice streams; drumlins; erosion ID BASAL CONDITIONS; WEST ANTARCTICA; GLACIER-BED; SEDIMENT; FLOW; LAURENTIDE; SHEET; DISCHARGE; ALASKA; RATES AB What happens beneath a glacier affects the way it flows and the landforms left behind when it retreats. Direct observations from beneath glaciers are, however, rare and the subglacial environment remains poorly understood. We present new, repeat observations from West Antarctica that show active processes beneath a modern glacier which can normally only be postulated from the geological record. We interpret erosion at a rate of 1 m a(-1) beneath a fast-flowing ice stream, followed by cessation of erosion and the formation of a drumlin from mobilized sediment. We also interpret both mobilization and increased compaction of basal sediment with associated hydrological changes within the glacier bed. All these changes occurred on time scales of a few years or less. This variability suggests that an ice stream can reorganize its bed rapidly, and that present models of ice dynamics may not simulate all the relevant subglacial processes. C1 British Antarctic Survey, NERC, Cambridge CB3 0ET, England. Univ Coll Swansea, Swansea SA2 8PP, W Glam, Wales. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Smith, AM (reprint author), British Antarctic Survey, NERC, Madingley Rd, Cambridge CB3 0ET, England. RI N, Keith/E-9126-2010; Vaughan, David/C-8348-2011; Makinson, Keith/A-2495-2013; Adalgeirsdottir, Gudfinna/M-3073-2015 OI Makinson, Keith/0000-0002-5791-1767; Adalgeirsdottir, Gudfinna/0000-0002-3442-2733 NR 31 TC 107 Z9 107 U1 4 U2 40 PU GEOLOGICAL SOC AMER, INC PI BOULDER PA PO BOX 9140, BOULDER, CO 80301-9140 USA SN 0091-7613 EI 1943-2682 J9 GEOLOGY JI Geology PD FEB PY 2007 VL 35 IS 2 BP 127 EP 130 DI 10.1103/G23036A PG 4 WC Geology SC Geology GA 132NC UT WOS:000243948500008 ER PT J AU Navarro-Gonzalez, R Mahan, SA Singhvi, AK Navarro-Aceves, R Rajot, JL McKay, CP Coll, P Raulin, F AF Navarro-Gonzalez, Rafael Mahan, Shannon A. Singhvi, Ashok K. Navarro-Aceves, Rafael Rajot, Jean-Louis McKay, Christopher P. Coll, Patrice Raulin, Francois TI Paleoecology reconstruction from trapped gases in a fulgurite from the late Pleistocene of the Libyan Desert SO GEOLOGY LA English DT Article DE fulgurite; thermoluminescence; lightning; Libyan desert; Sahel; paleoenvironment; Pleistocene ID NITROGEN-FIXATION; NITRIC-OXIDE; ARABIAN PENINSULA; FEEDBACKS; AFRICA; ENERGY AB When lightning strikes the ground, it heats, melts, and fuses the sand in soils to form glass tubes known as fulgurites. We report here the composition of CO, CO, and NO contained within the glassy bubbles of a fulgurite from the Libyan Desert. The results show that the fulgurite formed when the ground contained 0.1 wt% organic carbon with a C/N ratio of 10-15 and a delta C-13 of -13.96 parts per thousand, compositions similar to those found in the present-day semiarid region of the Sahel, where the vegetation is dominated by C, plants. Thermoluminescence dating indicates that this fulgurite formed similar to 15 k.y. ago. These results imply that the semiarid Sahel (at 17 degrees N) reached at least to 24 degrees N at this time, and demonstrate that fuligurite gases and luminescence geochronology can be used in quantitative paleoecology. C1 Univ Nacl Autonoma Mexico, Inst Ciencias Nucl, Lab Quim Plasmas & Estudios Planetarios, Mexico City 04510, DF, Mexico. Univ Paris 12, CNRS, UMR 7583, Lab Interuniv Syst Atmospher, F-94010 Creteil, France. Univ Paris 07, CMC, F-94010 Creteil, France. US Geol Survey, Denver Fed Ctr, Lakewood, CO 80225 USA. Phys Res Lab, Planetary & Geosci Div, Ahmadabad 380009, Gujarat, India. Inst Rech Dev, Niamey, Niger. NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA. RP Navarro-Gonzalez, R (reprint author), Univ Nacl Autonoma Mexico, Inst Ciencias Nucl, Lab Quim Plasmas & Estudios Planetarios, Circuito Exterior,Ciudad Univ,Apartado Postal 70, Mexico City 04510, DF, Mexico. RI Gonzalez, Rafael/D-1748-2009; RAJOT, Jean Louis/J-5635-2016; OI RAJOT, Jean Louis/0000-0002-3428-5636; Mahan, Shannon/0000-0001-5214-7774 NR 30 TC 14 Z9 14 U1 1 U2 3 PU GEOLOGICAL SOC AMERICA, INC PI BOULDER PA PO BOX 9140, BOULDER, CO 80301-9140 USA SN 0091-7613 J9 GEOLOGY JI Geology PD FEB PY 2007 VL 35 IS 2 BP 171 EP 174 DI 10.1130/G23246A.1 PG 4 WC Geology SC Geology GA 132NC UT WOS:000243948500020 ER PT J AU Nerem, RS Cazenave, A Chambers, DP Fu, LL Leuliette, EW Mitchum, GT AF Nerem, R. S. Cazenave, A. Chambers, D. P. Fu, L. L. Leuliette, E. W. Mitchum, G. T. TI Comment on "Estimating future sea level change from past records" by Nils-Axel Morner SO GLOBAL AND PLANETARY CHANGE LA English DT Editorial Material ID TIDE GAUGES; RISE C1 Univ Colorado, Colorado Ctr Astrodynam Res, Boulder, CO 80309 USA. Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. LEGOS CNES, Toulouse, France. Univ Texas, Ctr Space Res, Austin, TX 78712 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. Univ S Florida, Coll Marine Sci, Tampa, FL USA. RP Nerem, RS (reprint author), Univ Colorado, Colorado Ctr Astrodynam Res, Boulder, CO 80309 USA. EM nerem@colorado.edu RI Leuliette, Eric/D-1527-2010; OI Leuliette, Eric/0000-0002-3425-4039; Chambers, Don/0000-0002-5439-0257 NR 17 TC 4 Z9 4 U1 2 U2 18 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-8181 J9 GLOBAL PLANET CHANGE JI Glob. Planet. Change PD FEB PY 2007 VL 55 IS 4 BP 358 EP 360 DI 10.1016/j.gloplacha.2006.08.002 PG 3 WC Geography, Physical; Geosciences, Multidisciplinary SC Physical Geography; Geology GA 138BO UT WOS:000244337700009 ER PT J AU Bardavid, RE Ionescu, D Oren, A Rainey, FA Hollen, BJ Bagaley, DR Small, AM Mckay, C AF Bardavid, Rahel Elevi Ionescu, Danny Oren, Aharon Rainey, Fred A. Hollen, Becky J. Bagaley, Danielle R. Small, Alanna M. Mckay, Christopher TI Selective enrichment, isolation and molecular detection of Salinibacter and related extremely halophilic Bacteria from hypersaline environments SO HYDROBIOLOGIA LA English DT Article DE Salinibacter; Salterns; Death Valley; hypersaline; enrichment; anisomycin; bacitracin ID SALTERN CRYSTALLIZER PONDS; IN-SITU HYBRIDIZATION; ACID METHYL-ESTERS; SOLAR SALTERNS; DEATH-VALLEY; RUBER; HALOBACTERIA; NOV. AB Salinibacter is a genus of red, extremely halophilic Bacteria. Thus far the genus is represented by a single species, Salinibacter ruber, strains of which have been isolated from saltern crystallizer ponds in Spain and on the Balearic Islands. Both with respect to its growth conditions and its physiology, Salinibacter resembles the halophilic Archaea of the order Halobacteriales. We have designed selective enrichment and isolation techniques to obtain Salinibacter and related red extremely halophilic Bacteria from different hypersaline environments, based on their resistance to anisomycin and bacitracin, two antibiotics that are potent inhibitors of the halophilic Archaea. Using direct plating on media containing bacitracin, we found Salinibacter-like organisms in numbers between 1.4x10(3) and 1.4x10(6)ml(-1) in brines collected from the crystallizer ponds of the salterns in Eilat, Israel, being equivalent to 1.8-18% of the total colony counts obtained on identical media without bacitracin. A number of strains from Eilat were subjected to a preliminary characterization, and they proved similar to the type strain of S. ruber. We also report here the isolation and molecular detection of Salinibacter-like organisms from an evaporite crust on the bottom of salt pools at the Badwater site in Death Valley, CA. These isolates and environmental 16S rRNA gene sequences differ in a number of properties from S. ruber, and they may represent a new species of Salinibacter or a new related genus. C1 Hebrew Univ Jerusalem, Inst Life Sci, IL-91904 Jerusalem, Israel. Hebrew Univ Jerusalem, Moshe Shilo Minerva Ctr Marine Biogeochem, IL-91904 Jerusalem, Israel. Louisiana State Univ, Dept Biol Sci, Baton Rouge, LA 70803 USA. NASA, Ames Res Ctr, Div Life Sci, Moffett Field, CA 94035 USA. RP Oren, A (reprint author), Hebrew Univ Jerusalem, Inst Life Sci, IL-91904 Jerusalem, Israel. EM orena@shum.cc.huji.ac.il RI Rainey, Fred/C-8767-2013; OI Rainey, Fred/0000-0001-9129-6844; Ionescu, Danny/0000-0002-4658-8597 NR 31 TC 21 Z9 22 U1 0 U2 17 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0018-8158 J9 HYDROBIOLOGIA JI Hydrobiologia PD FEB PY 2007 VL 576 BP 3 EP 13 DI 10.1007/s10750-006-0288-8 PG 11 WC Marine & Freshwater Biology SC Marine & Freshwater Biology GA 120MR UT WOS:000243089500002 ER PT J AU Rodell, M Chen, JL Kato, H Famiglietti, JS Nigro, J Wilson, CR AF Rodell, Matthew Chen, Jianli Kato, Hiroko Famiglietti, James S. Nigro, Joe Wilson, Clark R. TI Estimating groundwater storage changes in the Mississippi River basin (USA) using GRACE SO HYDROGEOLOGY JOURNAL LA English DT Article DE groundwater monitoring; water budget; Mississippi River basin; geophysical methods; remote sensing ID CLIMATE EXPERIMENT GRACE; DATA ASSIMILATION SYSTEM; LAND-SURFACE MODEL; WATER STORAGE; GRAVITY RECOVERY; MASS VARIABILITY; PRECIPITATION; EVAPOTRANSPIRATION; ILLINOIS; AQUIFER AB Based on satellite observations of Earth's time variable gravity field from the Gravity Recovery and Climate Experiment (GRACE), it is possible to derive variations in terrestrial water storage, which includes groundwater, soil moisture, and snow. Given auxiliary information on the latter two, one can estimate groundwater storage variations. GRACE may be the only hope for groundwater depletion assessments in data-poor regions of the world. In this study, soil moisture and snow were simulated by the Global Land Data Assimilation System (GLDAS) and used to isolate groundwater storage anomalies from GRACE water storage data for the Mississippi River basin and its four major sub-basins. Results were evaluated using water level records from 58 wells set in the unconfined aquifers of the basin. Uncertainty in the technique was also assessed. The GRACE-GLDAS estimates compared favorably with the well based time series for the Mississippi River basin and the two sub-basins that are larger than 900,000 km(2). The technique performed poorly for the two sub-basins that have areas of approximately 500,000 km(2). Continuing enhancement of the GRACE processing methods is likely to improve the skill of the technique in the future, while also increasing the temporal resolution. C1 NASA, Goddard Space Flight Ctr, Hydrol Sci Branch, Greenbelt, MD 20771 USA. Univ Texas, Ctr Space Res, Austin, TX 78759 USA. Univ Maryland, Earth Syst Sci Interdisciplinary Ctr, College Pk, MD 20742 USA. Univ Calif Irvine, Irvine, CA 92697 USA. Sci Syst & Applicat Inc, Lanham, MD 20706 USA. Univ Texas, Dept Geol Sci, Jackson Sch Geosci, Austin, TX 78712 USA. RP Rodell, M (reprint author), NASA, Goddard Space Flight Ctr, Hydrol Sci Branch, Code 614-3, Greenbelt, MD 20771 USA. EM Matthew.Rodell@nasa.gov RI Rodell, Matthew/E-4946-2012 OI Rodell, Matthew/0000-0003-0106-7437 NR 29 TC 159 Z9 171 U1 3 U2 64 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 1431-2174 J9 HYDROGEOL J JI Hydrogeol. J. PD FEB PY 2007 VL 15 IS 1 BP 159 EP 166 DI 10.1007/s10040-006-0103-7 PG 8 WC Geosciences, Multidisciplinary; Water Resources SC Geology; Water Resources GA 130NA UT WOS:000243805100016 ER PT J AU Hesman, BE Davis, GR Matthews, HE Orton, GS AF Hesman, Brigette E. Davis, Gary R. Matthews, Henry E. Orton, Glenn S. TI The abundance profile of CO in Neptune's atmosphere SO ICARUS LA English DT Article DE abundances, atmospheres; Neptune, atmosphere; radiative transfer; spectroscopy ID ROTOTRANSLATIONAL ABSORPTION-SPECTRA; CARBON-MONOXIDE; URANUS; TEMPERATURE; PAIRS; SUBMILLIMETER; CONSTRAINTS; WAVELENGTH; HYDROGEN; PLANETS AB The J = 3-2 rotational line of CO in Neptune has been measured using the heterodyne receiver B3 at the JCMT. The spectral resolution was 1.25 MHz and 25 tunings were used to cover a frequency range of almost 20 GHz. The measured line shape, encompassing both the broad absorption feature arising in the lower atmosphere and a narrow emission core from the upper stratosphere, indicates that the CO mole ratio is not uniform with altitude, with best-fit values of 2.2(-0.4)(+0.6) x 10(-6) in the upper stratosphere and 0.6 +/- 0.4 x 10(-6) in the lower stratosphere and troposphere. The higher stratospheric abundance indicates that a dual, internal and external, origin of CO is most likely. (c) 2006 Elsevier Inc. All rights reserved. C1 Univ Saskatchewan, Saskatoon, SK S7N 5E2, Canada. Joint Astron Ctr, Hilo, HI 96720 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. HIA, Natl Res Council Canada, Victoria, BC V9E 2E7, Canada. RP Hesman, BE (reprint author), NASA, Goddard Space Flight Ctr, Code 661, Greenbelt, MD 20771 USA. EM brigette.hesman@gsfc.nasa.gov NR 30 TC 22 Z9 22 U1 1 U2 1 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD FEB PY 2007 VL 186 IS 2 BP 342 EP 353 DI 10.1016/j.icarus.2006.08.025 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 134KF UT WOS:000244081200004 ER PT J AU de Kok, R Irwin, PGJ Teanby, NA Lellouch, E Bezard, B Vinatier, S Nixon, CA Fletcher, L Howett, C Calcutt, SB Bowles, NE Flasar, FM Taylor, FW AF de Kok, R. Irwin, P. G. J. Teanby, N. A. Lellouch, E. Bezard, B. Vinatier, S. Nixon, C. A. Fletcher, L. Howett, C. Calcutt, S. B. Bowles, N. E. Flasar, F. M. Taylor, F. W. TI Oxygen compounds in Titan's stratosphere as observed by Cassini CIRS SO ICARUS LA English DT Article DE titan; atmospheres, composition ID ROTOTRANSLATIONAL ABSORPTION-SPECTRA; MILLIMETER HETERODYNE OBSERVATIONS; MOLECULAR SPECTROSCOPIC DATABASE; VOYAGER INFRARED OBSERVATIONS; MIXED VERTICAL PROFILE; CARBON-MONOXIDE; LATITUDINAL VARIATIONS; ATMOSPHERE; PAIRS; TEMPERATURES AB We have investigated the abundances of Titan's stratospheric oxygen compounds using 0.5 cm(-1) resolution spectra from the Composite Infrared Spectrometer on the Cassini orbiter. The CO abundance was derived for several observations of far-infrared nadir spectra, taken at a range of latitudes (75 degrees S-35 degrees N) and emission angles (0 degrees-60 degrees), using rotational lines that have not been analysed before the arrival of Cassini at Saturn. The derived volume mixing ratios for the different observations are mutually consistent regardless of latitude. The weighted mean CO volume mixing ratio is 47 +/- 8ppm if CO is assumed to be uniform with latitude. H2O could not be detected and an upper limit of 0.9 ppb was determined. CO2 abundances derived from mid-infrared nadir spectra show no significant latitudinal variations, with typical values of 16 +/- 2 ppb. Mid-infrared limb spectra at 55 degrees S were used to constrain the vertical profile Of CO2 for the first time. A vertical CO2 profile that is constant above the condensation level at a volume mixing ratio of 15 ppb reproduces the limb spectra very well below 200 km. This is consistent with the long chemical lifetime Of CO2 in Titan's stratosphere. Above 200 km the CO2 volume mixing ratio is not well constrained and an increase with altitude cannot be ruled out there. (c) 2006 Elsevier Inc. All rights reserved. C1 Univ Oxford, Clarendon Lab, Dept Phys, Oxford OX1 3PU, England. Observ Paris, LESIA, F-92195 Meudon, France. Univ Paris 06, UMR 8109, F-75005 Paris, France. Univ Maryland, Dept Astron, College Pk, MD 20742 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP de Kok, R (reprint author), Univ Oxford, Clarendon Lab, Dept Phys, Parks Rd, Oxford OX1 3PU, England. EM remco@atm.ox.ac.uk RI Fletcher, Leigh/D-6093-2011; Nixon, Conor/A-8531-2009; Flasar, F Michael/C-8509-2012; OI Fletcher, Leigh/0000-0001-5834-9588; Nixon, Conor/0000-0001-9540-9121; Irwin, Patrick/0000-0002-6772-384X; Calcutt, Simon/0000-0002-0102-3170; Teanby, Nicholas/0000-0003-3108-5775 NR 47 TC 67 Z9 68 U1 0 U2 6 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 EI 1090-2643 J9 ICARUS JI Icarus PD FEB PY 2007 VL 186 IS 2 BP 354 EP 363 DI 10.1016/j.icarus.2006.09.016 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 134KF UT WOS:000244081200005 ER PT J AU Teanby, NA Irwin, RJ de Kok, R Vinatier, S Bezard, B Nixon, CA Flasar, FM Calcutt, SB Bowles, NE Fletcher, L Howett, C Taylor, FW AF Teanby, N. A. Irwin, P. G. J. de Kok, R. Vinatier, S. Bezard, B. Nixon, C. A. Flasar, F. M. Calcutt, S. B. Bowles, N. E. Fletcher, L. Howett, C. Taylor, F. W. TI Vertical profiles of HCN, HC3N, and C2H2 in Titan's atmosphere derived from Cassini/CIRS data SO ICARUS LA English DT Article DE titan; atmospheres, composition ID ROTOTRANSLATIONAL ABSORPTION-SPECTRA; VOYAGER INFRARED OBSERVATIONS; HETERODYNE OBSERVATIONS; SPECTROSCOPIC DATABASE; TEMPERATURE-DEPENDENCE; LATITUDINAL VARIATIONS; PAIRS; BAND; STRATOSPHERE; HITRAN AB Mid-infrared limb spectra in the range 600-1400 cm(-1) taken with the Composite InfraRed Spectrometer (CIRS) on-board the Cassini spacecraft were used to determine vertical profiles of HCN, HC3N, C2H2, and temperature in Titan's atmosphere. Both high (0.5 cm(-1)) and low (13.5 cm(-1)) spectral resolution data were used. The 0.5 cm(-1) data gave profiles at four latitudes and the 13.5 cm(-1) data gave almost complete latitudinal coverage of the atmosphere. Both datasets were found to be consistent with each other. High temperatures in the upper stratosphere and mesosphere were observed at Titan's northern winter pole and were attributed to adiabatic heating in the subsiding branch of a meridional circulation cell. On the other hand, the lower stratosphere was much colder in the north than at the equator, which can be explained by the lack of solar radiation and increased IR emission from volatile enriched air. HC3N had a vertical profile consistent with previous ground based observations at southern and equatorial latitudes, but was massively enriched near the north pole. This can also be explained in terms of subsidence at the winter pole. A boundary observed at 60 degrees N between enriched and un-enriched air is consistent with a confining polar vortex at 60 degrees N and HC3N's short lifetime. In the far north, layers were observed in the HC3N profile that were reminiscent of haze layers observed by Cassini's imaging cameras. HCN was also enriched over the north pole, which gives further evidence for subsidence. However, the atmospheric cross section obtained from 13.5 cm(-1) data indicated a HCN enriched layer at 200-250 km, extending into the southern hemisphere. This could be interpreted as advection of polar enriched air towards the south by a meridional circulation cell. This is observed for HCN but not for HC3N due to HCN's longer photochemical lifetime. C2H2 appears to have a uniform abundance with altitude and is not significantly enriched in the north. This is consistent with observations from previous CIRS analysis that show increased abundances of nitriles and hydrocarbons but not C2H2 towards the north pole. (c) 2006 Elsevier Inc. All rights reserved. C1 Univ Oxford, Clarendon Lab, Dept Phys, Oxford OX1 3PU, England. Observ Paris, LESIA, F-92195 Meudon, France. Univ Maryland, Dept Astron, College Pk, MD 20742 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Teanby, NA (reprint author), Univ Oxford, Clarendon Lab, Dept Phys, Parks Rd, Oxford OX1 3PU, England. EM teanby@atm.ox.ac.uk RI Fletcher, Leigh/D-6093-2011; Nixon, Conor/A-8531-2009; Flasar, F Michael/C-8509-2012; OI Fletcher, Leigh/0000-0001-5834-9588; Nixon, Conor/0000-0001-9540-9121; Calcutt, Simon/0000-0002-0102-3170; Teanby, Nicholas/0000-0003-3108-5775; Irwin, Patrick/0000-0002-6772-384X NR 51 TC 84 Z9 84 U1 0 U2 3 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 EI 1090-2643 J9 ICARUS JI Icarus PD FEB PY 2007 VL 186 IS 2 BP 364 EP 384 DI 10.1016/j.icarus.2006.09.024 PG 21 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 134KF UT WOS:000244081200006 ER PT J AU Lopes, RMC Mitchell, KL Stofan, ER Lunine, JI Lorenz, R Paganelli, F Kirk, RL Wood, CA Wall, SD Robshaw, LE Fortes, AD Neish, CD Radebaugh, J Reffet, E Ostro, SJ Elachi, C Allison, MD Anderson, Y Boehmer, R Boubin, G Callahan, P Encrenaz, P Flamini, E Francescetti, G Gim, Y Hamilton, G Hensley, S Janssen, MA Johnson, WTK Kelleher, K Muhleman, DO Ori, G Orosei, R Picardi, G Posa, F Roth, LE Seu, R Shaffer, S Soderblom, LA Stiles, B Vetrella, S West, RD Wye, L Zebker, HA AF Lopes, R. M. C. Mitchell, K. L. Stofan, E. R. Lunine, J. I. Lorenz, R. Paganelli, F. Kirk, R. L. Wood, C. A. Wall, S. D. Robshaw, L. E. Fortes, A. D. Neish, C. D. Radebaugh, J. Reffet, E. Ostro, S. J. Elachi, C. Allison, M. D. Anderson, Y. Boehmer, R. Boubin, G. Callahan, P. Encrenaz, P. Flamini, E. Francescetti, G. Gim, Y. Hamilton, G. Hensley, S. Janssen, M. A. Johnson, W. T. K. Kelleher, K. Muhleman, D. O. Ori, G. Orosei, R. Picardi, G. Posa, F. Roth, L. E. Seu, R. Shaffer, S. Soderblom, L. A. Stiles, B. Vetrella, S. West, R. D. Wye, L. Zebker, H. A. TI Cryovolcanic features on Titan's surface as revealed by the Cassini Titan Radar Mapper SO ICARUS LA English DT Article DE titan; volcanism; satellites of Saturn ID STEEP-SIDED DOMES; PLANETOLOGICAL APPLICATIONS; INTERNAL STRUCTURE; HUYGENS PROBE; LAVA FLOWS; EMPLACEMENT; VENUS; EUROPA; LIQUID; ATMOSPHERE AB The Cassini Titan Radar Mapper obtained Synthetic Aperture Radar images of Titan's surface during four fly-bys during the mission's first year. These images show that Titan's surface is very complex geologically, showing evidence of major planetary geologic processes, including cryovolcanism. This paper discusses the variety of cryovolcanic features identified from SAR images, their possible origin, and their geologic context. The features which we identify as cryovolcanic in origin include a large (180 km diameter) volcanic construct (dome or shield), several extensive flows, and three calderas which appear to be the source of flows. The composition of the cryomagma on Titan is still unknown, but constraints on rheological properties can be estimated using flow thickness. Rheological properties of one flow were estimated and appear inconsistent with ammonia-water slurries, and possibly more consistent with ammonia-water-methanol slurries. The extent of cryovolcanism on Titan is still not known, as only a small fraction of the surface has been imaged at sufficient resolution. Energetic considerations suggest that cryovolcanism may have been a dominant process in the resurfacing of Titan. (c) 2006 Elsevier Inc. All rights reserved. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Proxemy Res, Bowie, MD 20715 USA. Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. US Geol Survey, Flagstaff, AZ 86001 USA. Wheeling Jesuit Univ, Wheeling, WV 26003 USA. Univ Lancaster, Dept Environm Sci, Lancaster LA1 4YQ, England. UCL, Dept Earth Sci, London WC1E 6BT, England. NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Observ Paris, F-92195 Meudon, France. Agenzia Spaziale Italiana, I-00131 Rome, Italy. Fac Ingn, I-80125 Naples, Italy. CALTECH, Div Geol & Planetary Sci, Pasadena, CA 91125 USA. IRSPS, Pescara, Italy. CNR, IASF, I-00133 Rome, Italy. Univ Roma La Sapienza, I-00184 Rome, Italy. INFM, I-70126 Bari, Italy. Politecn Bari, Dipartimento Interateneo Fis, I-70126 Bari, Italy. Stanford Univ, Stanford, CA 94305 USA. INAF, IFSI, I-00133 Rome, Italy. RP Lopes, RMC (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM rosaly.m.lopes@jpl.nasa.gov RI Fortes, Andrew/C-1349-2011; Neish, Catherine/G-6321-2012; Lorenz, Ralph/B-8759-2016; Lopes, Rosaly/D-1608-2016; OI Fortes, Andrew/0000-0001-5907-2285; Lorenz, Ralph/0000-0001-8528-4644; Lopes, Rosaly/0000-0002-7928-3167; ORI, Gian Gabriele/0000-0002-6460-1476 NR 59 TC 122 Z9 123 U1 2 U2 17 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD FEB PY 2007 VL 186 IS 2 BP 395 EP 412 DI 10.1016/j.icarus.2006.09.006 PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 134KF UT WOS:000244081200008 ER PT J AU Howell, RR Lopes, RMC AF Howell, Robert R. Lopes, Rosaly M. C. TI The nature of the volcanic activity at Loki: Insights from Galileo NIMS and PPR data SO ICARUS LA English DT Article DE Io; volcanism; infrared observations; Jupiter, satellites; satellites, surfaces; geological processes ID INFRARED MAPPING SPECTROMETER; GROUND-BASED OBSERVATIONS; SILICATE VOLCANISM; PHOTOPOLARIMETER-RADIOMETER; THERMAL EMISSION; HOT-SPOTS; HEAT-FLOW; IO; TEMPERATURE; VOYAGER-1 AB Loki is the largest patera and the most energetic hotspot on Jupiter's moon Io, in turn the most volcanically active body in the Solar System, but the nature of the activity remains enigmatic. We present detailed analysis of Galileo Near-Infrared Mapping Spectrometer (NIMS) and PhotoPolarimeter/Radiometer (PPR) observations covering the 1.5-100 mu m wavelength range during the 124, 127, and 132 flybys. The general pattern of activity during these flybys is consistent with previously proposed models of a resurfacing wave periodically crossing a silicate lava lake. In particular our analysis of the 132 NIMS observations shows, over much of the observed patera, surface temperatures and implied ages closely matching those expected for a wave advancing counterclockwise at 0.94-1.38 km/day. The age pattern is different than other published analyses which do not show as clearly this azimuthal pattern. Our analysis also shows two additional distinctly different patera surfaces. The first is located along the inner and outer margins where components with a 3.00-4.70-mu m color temperature of 425 K exist. The second is located at the southwestern margin where components with a 550-K color temperature exist. Although the high temperatures could be caused by disruption of a lava lake crust, some additional mechanism is required to explain why the southwest margin is different from the inner or outer ones. Finally, analysis of the temperature profiles across the patera reveal a smoothness that is difficult to explain by simple lava cooling models. Paradoxically, at a subpixel level, wide temperature distributions exist which may be difficult to explain by just the presence of hot cracks in the lava crust. The resurfacing wave and lava cooling models explain well the overall characteristics of the observations. However, additional physical processes, perhaps involving heat transport by volatiles, are needed to explain the more subtle features. (c) 2006 Elsevier Inc. All rights reserved. C1 Univ Wyoming, Dept Geol & Geophys, Laramie, WY 82071 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Howell, RR (reprint author), Univ Wyoming, Dept Geol & Geophys, Laramie, WY 82071 USA. EM rhowell@uwyo.edu RI Lopes, Rosaly/D-1608-2016 OI Lopes, Rosaly/0000-0002-7928-3167 NR 42 TC 11 Z9 11 U1 0 U2 1 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD FEB PY 2007 VL 186 IS 2 BP 448 EP 461 DI 10.1016/j.icarus.2006.09.022 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 134KF UT WOS:000244081200012 ER PT J AU Potter, AE Killen, RM Morgan, TH AF Potter, A. E. Killen, R. M. Morgan, T. H. TI Solar radiation acceleration effects on Mercury sodium emission SO ICARUS LA English DT Article DE Mercury; atmospheres, dynamics; atmospheres, structure ID ATMOSPHERE; ABUNDANCE; TAIL AB A set of Mercury sodium emission data collected over a range of true anomaly angles during 1997-2003 was used to analyze the effect of solar radiation acceleration on sodium emissions. The variation of emission intensity with changing Doppler velocities throughout the orbit was minimized by normalizing the intensities to a constant true anomaly angle. The normalized intensities should be independent of orbital position if sodium density is constant. Plots of the normalized intensities against solar radiation acceleration showed very considerable scatter. However, the scatter was not random, but the result of a systematic variation, such that the normalized emission at a particular value of radiation acceleration took one or the other of two values, depending on the value of the true anomaly angle. We propose that this was the result of solar radiation acceleration changing the velocity of the sodium atoms, and consequently changing the solar continuum seen by the atoms. There is a positive feedback loop in the "out" leg of the orbit, such that radiation acceleration increases the solar continuum intensity seen by the atoms, and a negative feedback loop in the "in" leg of the orbit, such radiation acceleration decreases the continuum intensity. The observations could be approximately fit by assuming that sodium atoms are exposed to sunlight for an average of 1700s. The emission values corrected for this effect showed much less scatter, with a general trend of about 30% to lower values from minimum to maximum radiation acceleration. The corrected emissions were used to calculate average column densities, and the result compared with the predictions of Smyth and Marconi [Smyth, W.H., Marconi, M.L., 1995. Astrophys. J. 441, 839-864] for the variation of column density with true anomaly angle. The comparison suggests that sodium atoms interact weakly with the surface. The effect of radiation acceleration on emission intensities should be taken into account if column densities are to be calculated from emission intensities. (c) 2006 Elsevier Inc. All rights reserved. C1 Natl Solar Observ, Tucson, AZ 85726 USA. Univ Maryland, Dept Astron, College Pk, MD 20742 USA. NASA Headquarters, Washington, DC 20546 USA. RP Potter, AE (reprint author), Natl Solar Observ, POB 26732,950 N Cherry Ave, Tucson, AZ 85726 USA. EM apotter@noao.edu RI Killen, Rosemary/E-7127-2012; Morgan, Thomas/I-5943-2013 NR 14 TC 37 Z9 37 U1 0 U2 2 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD FEB PY 2007 VL 186 IS 2 BP 571 EP 580 DI 10.1016/j.icarus.2006.09.025 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 134KF UT WOS:000244081200021 ER PT J AU Busch, MW Ostro, SJ Benner, LAM Giorgim, JD Magri, C Howell, ES Nolan, MC Hine, AA Campbell, DB Shapiro, II Chandler, JF AF Busch, Michael W. Ostro, Steven J. Benner, Lance A. M. Giorgim, Jon D. Magri, Christopher Howell, Ellen S. Nolan, Michael C. Hine, Alice A. Campbell, Donald B. Shapiro, Irwin I. Chandler, John F. TI Arecibo radar observations of Phobos and Deimos SO ICARUS LA English DT Article DE Mars, satellites; radar observations; regoliths ID ASTEROIDS; GRAVITY AB In November 2005, we observed the moons of Mars using the Arecibo 2380-MHz (13-cm) radar, obtaining a result for the OC radar albedo of Phobos (0.056 +/- 0.014) consistent with its previously reported radar albedo and implying an upper bound on its near-surface bulk density of 1.6 +/- 0.3 g cm(-3). We detected Deimos by radar for the first time, finding its OC radar albedo to be 0.021 +/- 0.006, implying an upper bound on its near-surface density of 1.1 +/- 0.3 g cm(-3), consistent with a high-porosity regolith. We briefly discuss reasons for these low radar albedos, Deimos' being possibly the lowest of any Solar System body yet observed by radar. (c) 2006 Elsevier Inc. All rights reserved. C1 CALTECH, Div Geol & Planetary Sci, Pasadena, CA 91125 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Maine, Farmington, ME 04938 USA. Natl Astron & Ionosphere Ctr, Arecibo Observ, Arecibo, PR 00612 USA. Cornell Univ, Dept Astron, Ithaca, NY 14853 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Busch, MW (reprint author), CALTECH, Div Geol & Planetary Sci, MC 150-21, Pasadena, CA 91125 USA. EM busch@caltech.edu RI Nolan, Michael/H-4980-2012 OI Nolan, Michael/0000-0001-8316-0680 NR 19 TC 6 Z9 6 U1 1 U2 2 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD FEB PY 2007 VL 186 IS 2 BP 581 EP 584 DI 10.1016/j.icarus.2006.11.003 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 134KF UT WOS:000244081200022 ER PT J AU Davies, AG Matson, DL Veeder, GJ Johnson, TV Blaney, DL AF Davies, Ashley Gerard Matson, Dennis L. Veeder, Glenn J. Johnson, Torrence V. Blaney, Diana L. TI Post-solidification cooling and the age of Io's lava flows (vol 176, pg 123, 2005) SO ICARUS LA English DT Correction C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Davies, AG (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM ashley.davies@jpl.nasa.gov NR 1 TC 0 Z9 0 U1 0 U2 1 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD FEB PY 2007 VL 186 IS 2 BP 590 EP 590 DI 10.1016/j.icarus.2006.11.001 PG 1 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 134KF UT WOS:000244081200025 ER PT J AU Barrett, A Rabideau, G Estlin, T Chien, S AF Barrett, Anthony Rabideau, Gregg Estlin, Tara Chien, Steve TI Coordinated continual planning methods for cooperating rovers SO IEEE AEROSPACE AND ELECTRONIC SYSTEMS MAGAZINE LA English DT Article AB Eight evaluation metrics are used to compare and contrast three coordination schemes for a system that continuously plans to control collections of rovers (or spacecraft) using collective mission goals instead of goals or command sequences for each spacecraft. These schemes use a central coordinator to either: 1) micromanage rover; one activity at a time; 2) assign mission goals to rovers; or 3) arbitrate mission goal auctions among rovers. A self-commanding collection of rovers would autonomously coordinate itself to satisfy high-level science and engineering goals in a changing partially understood environment-making the operation of tens or even a hundred spacecraft feasible. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Barrett, A (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 126-347, Pasadena, CA 91109 USA. NR 17 TC 3 Z9 3 U1 0 U2 4 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 0885-8985 J9 IEEE AERO EL SYS MAG JI IEEE Aerosp. Electron. Syst. Mag. PD FEB PY 2007 VL 22 IS 2 BP 27 EP 33 DI 10.1109/MAES.2007.323296 PG 7 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA 140JE UT WOS:000244500000005 ER PT J AU U-yen, K Wollack, EJ Horst, S Doiron, T Papapolymerou, J Laskar, J AF U-yen, Kongpop Wollack, Edward J. Horst, Stephen Doiron, Terence Papapolymerou, John Laskar, Joy TI Slotline stepped circular rings for low-loss micro strip-to-slotline transitions SO IEEE MICROWAVE AND WIRELESS COMPONENTS LETTERS LA English DT Article DE microstrip (MS) circuits; slotline (SL); SL transitions AB We propose a low-loss slotline (SL) stepped circular ring termination for use in a microstrip-to-slotline (MS-to-SL) transition. Not only does this termination achieve broadband characteristics, but it also reduces SL radiation. The experimental results show that, using the proposed technique, the radiation loss around the pass-band frequency is lower than that of the conventional transitions using radial or circular pad terminations. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Georgia Inst Technol, Atlanta, GA 30332 USA. RP U-yen, K (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. EM kuyen@pop500.gsfc.nasa.gov RI Wollack, Edward/D-4467-2012 OI Wollack, Edward/0000-0002-7567-4451 NR 6 TC 8 Z9 9 U1 0 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 1531-1309 J9 IEEE MICROW WIREL CO JI IEEE Microw. Wirel. Compon. Lett. PD FEB PY 2007 VL 17 IS 2 BP 100 EP 102 DI 10.1109/LMWC.2006.890328 PG 3 WC Engineering, Electrical & Electronic SC Engineering GA 137AK UT WOS:000244265000006 ER PT J AU Brenner, AC DiMarzio, JR Zwally, HJ AF Brenner, Anita C. DiMarzio, John R. Zwally, H. Jay TI Precision and accuracy of satellite radar and laser altimeter data over the continental ice sheets SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE altimetry; ice; laser measurements; radar altimetry; remote sensing ID ELEVATION CHANGE; PENETRATION; DEPTH AB The unprecedented accuracy of elevations retrieved from the Ice Cloud and Land Elevation Satellite (ICESat) laser altimeter is investigated and used to characterize the range errors in the Environmental Satellite (Envisat) and European Remote Sensing 2 Satellite (ERS-2) radar altimeters over the continental ice sheets. Cross-mission crossover analysis between time-coincident ERS-2-, Envisat-, and ICESat-retrieved elevations and comparisons to an ICESat-derived digital elevation map are used to quantify the radar elevation error budget as a function of surface slope and to investigate the effectiveness of a method to account for the radar altimeter slope-induced error. The precision and accuracy of the elevations retrieved from the ICESat Geoscience Laser Altimeter System and the European Space Agency radar altimeters on ERS-2 and Envisat are calculated over the Greenland and Antarctic ice sheets using a crossover analysis. As a result of this work, the laser precision is found to vary as a function of surface slope from 14 to 59 cm, and the radar precision varies from 59 cm to 3.7 m for ERS-2 and from 28 cm to 2.06 m for Envisat. Envisat elevation retrievals when compared with ICESat results over regions with less than 0.1 degrees surface slopes show a mean difference of 9 +/- 5 cm for Greenland and -40 +/- 98 cm over Antarctica. ERS-2 elevation retrievals over these same low surface slope regions differ from ICESat results by -56 +/- 72 cm over Greenland and 1.12 +/- 1.16 m over Antarctica. At higher surface slopes of 0.7 degrees to 0.8 degrees, the Envisat/ICESat differences increase to -2.27 +/- 23 m over Greenland and to 0.05 +/- 26 m over Antarctica. C1 Sci Applicat Int Corp, Lanham, MD 20706 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Brenner, AC (reprint author), Sci Applicat Int Corp, Lanham, MD 20706 USA. EM Anita_Brenner@ssaihq.com; john.p.dimarzio@gsfc.nasa.gov; H.J.Zwally@nasa.gov NR 22 TC 73 Z9 80 U1 2 U2 24 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD FEB PY 2007 VL 45 IS 2 BP 321 EP 331 DI 10.1106/TGRS.2006.887172 PG 11 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 131GU UT WOS:000243857700004 ER PT J AU Dobigeon, N Tourneret, JY Scargle, JD AF Dobigeon, Nicolas Tourneret, Jean-Yves Scargle, Jeffrey D. TI Joint segmentation of multivariate astronomical time series: Bayesian sampling with a hierarchical model SO IEEE TRANSACTIONS ON SIGNAL PROCESSING LA English DT Article DE Gibbs sampling; hierarchical Bayesian analysis; Markov chain Monte Carlo; photon counting data; segmentation ID MULTIPLE CHANGE-POINTS; SIGNAL SEGMENTATION; SHIFTS; NOISE; MCMC AB Astronomy and other sciences often face the problem of detecting and characterizing structure in two. or more related time series. This paper approaches such problems using Bayesian priors to represent relationships between signals with various degrees of certainty, and not just rigid constraints. The segmentation is conducted by using a hierarchical Bayesian approach to a piece- wise constant Poisson rate model. A Gibbs sampling strategy allows joint estimation of the unknown parameters and hyperparameters. Results obtained with synthetic and real photon counting data illustrate the performance of the proposed algorithm. C1 TeSA, ENSEEIHT, IRIT, F-31071 Toulouse 7, France. NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA. RP Dobigeon, N (reprint author), TeSA, ENSEEIHT, IRIT, F-31071 Toulouse 7, France. EM Nicolas.Dobigeon@enseeiht.fr; Jean-Yves.Tourneret@tesa.prd.fr; Jeffrey.D.Scargle@nasa.gov OI Dobigeon, Nicolas/0000-0001-8127-350X NR 21 TC 24 Z9 24 U1 0 U2 4 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 1053-587X J9 IEEE T SIGNAL PROCES JI IEEE Trans. Signal Process. PD FEB PY 2007 VL 55 IS 2 BP 414 EP 423 DI 10.1109/TSP.2006.885768 PG 10 WC Engineering, Electrical & Electronic SC Engineering GA 132OR UT WOS:000243952600002 ER PT J AU Memarsadeghi, N Mount, DM Netanyahu, NS Le Moigne, J AF Memarsadeghi, Nargess Mount, David M. Netanyahu, Nathan S. Le Moigne, Jacqueline TI A fast implementation of the ISODATA clustering algorithm SO INTERNATIONAL JOURNAL OF COMPUTATIONAL GEOMETRY & APPLICATIONS LA English DT Article DE clustering; ISODATA; k-means; filtering algorithm; kd-trees; approximation ID 2-CENTER PROBLEM; THEOREM AB Clustering is central to many image processing and remote sensing applications. ISODATA is one of the most popular and widely used clustering methods in geoscience applications, but it can run slowly, particularly with large data sets. We present a more efficient approach to ISODATA clustering, which achieves better running times by storing the points in a kd-tree and through a modification of the way in which the algorithm estimates the dispersion of each cluster. We also present an approximate version of the algorithm which allows the user to further improve the running time, at the expense of lower fidelity in computing the nearest cluster center to each point. We provide both theoretical and empirical justification that our modified approach produces clusterings that are very similar to those produced by the standard ISODATA approach. We also provide empirical studies on both synthetic data and remotely sensed Landsat and MODIS images that show that our approach has significantly lower running times. C1 NASA, Goddard Space Flight Ctr, Adv Architectures & Automat Branch, Greenbelt, MD 20771 USA. Univ Maryland, Dept Comp Sci, College Pk, MD 20742 USA. Univ Maryland, Dept Comp Sci, College Pk, MD 20742 USA. Univ Maryland, Inst Adv Comp Sci, College Pk, MD 20742 USA. Bar Ilan Univ, Dept Comp Sci, IL-52900 Ramat Gan, Israel. Univ Maryland, Ctr Automat Res, College Pk, MD 20742 USA. RP Memarsadeghi, N (reprint author), NASA, Goddard Space Flight Ctr, Adv Architectures & Automat Branch, Greenbelt, MD 20771 USA. EM nargees@cs.umd.edu; mount@cs.umd.edu; nathan@cs.biu.ac.il; Jacqueline.LeMoigne@nasa.gov NR 41 TC 33 Z9 36 U1 0 U2 17 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA 5 TOH TUCK LINK, SINGAPORE 596224, SINGAPORE SN 0218-1959 EI 1793-6357 J9 INT J COMPUT GEOM AP JI Int. J. Comput. Geom. Appl. PD FEB PY 2007 VL 17 IS 1 BP 71 EP 103 DI 10.1142/S0218195907002252 PG 33 WC Computer Science, Theory & Methods; Mathematics, Applied SC Computer Science; Mathematics GA 229ZL UT WOS:000250845000004 ER PT J AU Kandula, M Haddad, GF Chen, RH AF Kandula, M. Haddad, G. F. Chen, R. -H. TI Three-dimensional thermal boundary layer corrections for circular heat flux gauges mounted in a flat plate with a surface temperature discontinuity SO INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER LA English DT Article DE convective heat flux gauges; surface temperature discontinuity; three-dimensional thermal boundary layers ID CALORIMETERS AB Three-dimensional Navier-Stokes computational fluid dynamics (CFD) analysis has been performed in an effort to determine thermal boundary layer correction factors for circular convective heat flux gauges (such as Schmidt-Boelter and plug type) mounted flush in a flat plate subjected to a stepwise surface temperature discontinuity. Turbulent flow solutions with temperature-dependent properties are obtained for a freestream Reynolds number of 1E6, and freestream Mach numbers of 2 and 4. The effect of gauge diameter and the plate surface temperature have been investigated. The 3D CFD results for the heat flux correction factors are compared to quasi-2D results deduced from constant property integral solutions and also 2D CFD analysis with both constant and variable properties. The role of three-dimensionality and of property variations on the heat flux correction factors has been demonstrated. (c) 2006 Elsevier Ltd. All rights reserved. C1 Sierra Lobo Inc, Kennedy Space Ctr, FL 32899 USA. NASA, Kennedy Space Ctr, FL 32899 USA. Univ Cent Florida, Mech Mat & Aerosp Engn Dept, Orlando, FL 32816 USA. RP Kandula, M (reprint author), Sierra Lobo Inc, Kennedy Space Ctr, FL 32899 USA. EM max.kandula-1@ksc.nasa.gov NR 29 TC 4 Z9 4 U1 1 U2 4 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0017-9310 J9 INT J HEAT MASS TRAN JI Int. J. Heat Mass Transf. PD FEB PY 2007 VL 50 IS 3-4 BP 713 EP 722 DI 10.1016/j.ijheatmasstransfer.2006.07.008 PG 10 WC Thermodynamics; Engineering, Mechanical; Mechanics SC Thermodynamics; Engineering; Mechanics GA 130CI UT WOS:000243776400028 ER PT J AU Valavala, PK Clancy, TC Odegard, GM Gates, TS AF Valavala, P. K. Clancy, T. C. Odegard, G. M. Gates, T. S. TI Nonlinear multiscale modeling of polymer materials SO INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES LA English DT Article DE multiscale modeling; molecular dynamics; computational chemistry; nanotechnology; polymers ID MOLECULAR-DYNAMICS SIMULATIONS; FORCE-FIELD; MECHANICAL-PROPERTIES; NANOTUBE COMPOSITES; CARBON; POLYIMIDES; PROTEINS; HYDROCARBONS; DIANHYDRIDE; DEPOSITION AB In this study, a hyperelastic multiscale modeling technique is used to predict elastic properties of polycarbonate and polyimide polymer systems using a set of widely accepted atomistic force fields. The model incorporates molecular simulations and a nonlinear, continuum mechanics-based, constitutive formulation that incorporates the behavior of the polymer materials as predicted from molecular simulations. The predicted properties of the polymers using multiple force fields are compared to experimentally measured values. Both static and dynamic molecular simulations are performed using molecular mechanics energy minimizations and molecular dynamics simulation techniques, respectively. The results of this study indicate that static molecular simulation is a useful tool to predict the bulk-level nonlinear mechanical behavior of polymers for finite deformations. It is found that the AMBER force field yields the most accurate predicted mechanical and physical properties of the modeled polymer systems compared to the other force fields used in this study. (c) 2006 Elsevier Ltd. All rights reserved. C1 Michigan Technol Univ, Dept Mech Engn Engn Mech, Houghton, MI 49931 USA. Natl Inst Aerosp, Hampton, VA 23666 USA. NASA, Langley Res Ctr, Mech Struct & Mat Branch, Hampton, VA 23681 USA. RP Odegard, GM (reprint author), Michigan Technol Univ, Dept Mech Engn Engn Mech, 1400 Townsend Dr, Houghton, MI 49931 USA. EM gmodegar@mtu.edu RI Valavala, Pavan/A-1268-2009; OI Odegard, Gregory/0000-0001-7577-6565 NR 48 TC 32 Z9 32 U1 1 U2 26 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0020-7683 J9 INT J SOLIDS STRUCT JI Int. J. Solids Struct. PD FEB PY 2007 VL 44 IS 3-4 BP 1161 EP 1179 DI 10.1016/j.ijsolstr.2006.06.011 PG 19 WC Mechanics SC Mechanics GA 123IJ UT WOS:000243289300024 ER PT J AU Satomi, M Vogel, BF Venkateswaran, K Gram, L AF Satomi, Masataka Vogel, Birte Fonnesbech Venkateswaran, Kasthuri Gram, Lone TI Description of Shewanella glacialipiscicola sp nov and Shewanella algidipiscicola sp nov., isolated from marine fish of the Danish Baltic Sea, and proposal that Shewanella affinis is a later heterotypic synonym of Shewanella colwelliana SO INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLOGY LA English DT Article ID SEQUENCE-ANALYSIS; BACTERIA; PUTREFACIENS; SPOILAGE; AMPLIFICATION; ALIGNMENT AB Two novel species belonging to the genus Shewanella are described on the basis of a polyphasic taxonomic approach. A total of 40 strains of Gram-negative, psychrotolerant, H2S-producing bacteria were isolated from marine fish (cod and plaice) caught in the Baltic Sea off Denmark. Strains belonging to group 1 (seven strains) were a lactate-assimilating variant of Shewanella morhuae with a G + C content of 44 mol%. The strains of group 2 (33 strains) utilized lactate, N-acetylglucosamine and malate but did not produce DNase or ornithine decarboxylase. Their G + C content was 47 mol%. Phylogenetic analysis of the 16S rRNA gene sequence data placed the two novel species within the genus Shewanella. Group 1 showed greatest sequence similarity with S. morhuae ATCC BAA-1205(T) (99.9%). However, gyrB gene sequence analysis and DNA-DNA hybridization differentiated these isolates from S. morhuae, with 95.6% sequence similarity and less than 57% DNA relatedness, respectively. Group 2 strains shared more than 99% 16S rRNA gene sequence similarity with the type strains of Shewanella colwelliana and Shewanella affinis, but gyrB sequence similarity (similar to 85%) and the results of DNA hybridization (similar to 28%) indicated that the new isolates represented a novel species. Furthermore, when compared to each other, the type strains of S. colwelliana and S. affinis had almost identical gyrB sequences and significantly high DNA reassociation values (76-83%), indicating that they belonged to the same species. Based on the conclusions of this study, we propose the novel species Shewanella glacialipiscicola sp. nov. (type strain T147(T) = LMG 23744(T) = NBRC 102030(T)) for group 1 strains and Shewanella algidipiscicola sp. nov. (type strain S13(T) = LMG 23746(T) = NBRC 102032(T)) for group 2 strains, and we propose that Shewanella affinis as a later heterotypic synonym of Shewanella colwelliana. C1 Fisheries Res Agcy, Natl Res Inst Fisheries Sci, Kanazawa Ku, Yokohama, Kanagawa 2368648, Japan. Tech Univ Denmark, Danish Inst Fisheries Res, Dept Seafood Res, Soltofts Plads, DK-2800 Lyngby, Denmark. CALTECH, Jet Prop Lab, Biotechnol & Planetary Protect Grp, Pasadena, CA 91109 USA. RP Satomi, M (reprint author), Fisheries Res Agcy, Natl Res Inst Fisheries Sci, Kanazawa Ku, 2-12-4 Fukuura, Yokohama, Kanagawa 2368648, Japan. EM msatomi@affrc.go.jp NR 27 TC 23 Z9 25 U1 0 U2 5 PU SOC GENERAL MICROBIOLOGY PI READING PA MARLBOROUGH HOUSE, BASINGSTOKE RD, SPENCERS WOODS, READING RG7 1AG, BERKS, ENGLAND SN 1466-5026 J9 INT J SYST EVOL MICR JI Int. J. Syst. Evol. Microbiol. PD FEB PY 2007 VL 57 BP 347 EP 352 DI 10.1099/ijs.0.64708-0 PN 2 PG 6 WC Microbiology SC Microbiology GA 141KL UT WOS:000244577200029 PM 17267977 ER PT J AU Spann, JF Wu, ST AF Spann, James F. Wu, S. -T. TI Challenges to modeling the Sun-Earth system: A workshop summary SO JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS LA English DT Editorial Material C1 NASA, Natl Space Sci & Technol Ctr, George C Marshall Space Flight Ctr, Sci & Explorat Res Off, Huntsville, AL 35805 USA. Univ Alabama, Ctr Space Plasma & Aeronom Res, Huntsville, AL 35899 USA. RP Spann, JF (reprint author), NASA, Natl Space Sci & Technol Ctr, George C Marshall Space Flight Ctr, Sci & Explorat Res Off, VP60,320 Sperkman Dr, Huntsville, AL 35805 USA. EM jim.spann@nasa.gov; wus@cspar.uah.edu NR 0 TC 0 Z9 0 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1364-6826 J9 J ATMOS SOL-TERR PHY JI J. Atmos. Sol.-Terr. Phys. PD FEB PY 2007 VL 69 IS 1-2 BP 1 EP 2 DI 10.1016/j.jastp.2006.10.001 PG 2 WC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences SC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences GA 141CC UT WOS:000244553100001 ER PT J AU Coffey, VN Chandler, MO Singh, N Avanov, L AF Coffey, V. N. Chandler, M. O. Singh, Nagendra Avanov, Levon TI End-to-end study of the transfer of energy from magnetosheath ion precipitation to the cusp SO JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS LA English DT Article; Proceedings Paper CT Huntsville Workshop on Challenges to Modeling the Sun-Earth System CY OCT 18-22, 2004 CL Huntsville, AL DE ion heating; magnetosheath/ionosphere coupling; particle/wave interactions; simulations ID PLASMA INJECTION; SIGNATURES; VIKING AB This paper describes a study of the effects of unstable magnetosheath distributions on the cusp ionosphere. A semikinetic model followed by a 2.5D particle-in-cell (PIC) model served as an end-to-end numerical system to study the evolved distributions from precipitation due to reconnection and, then secondly, the energy transfer into the high-latitude ionosphere based on these solar wind/magnetosheath inputs. Using inputs of several representative examples of magnetosheath injections, waves were generated at the lower hybrid frequency and energy transferred to the ionospheric electrons and ions. The resulting wave spectra and ion and electron particle heating was analyzed. (c) 2006 Elsevier Ltd. All rights reserved. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. Univ Alabama, Huntsville, AL 35812 USA. Space Res Inst, IKI, Moscow, Russia. RP Coffey, VN (reprint author), NASA, George C Marshall Space Flight Ctr, XD12, Huntsville, AL 35812 USA. EM Victoria.Coffey@nasa.gov NR 11 TC 0 Z9 0 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1364-6826 J9 J ATMOS SOL-TERR PHY JI J. Atmos. Sol.-Terr. Phys. PD FEB PY 2007 VL 69 IS 1-2 BP 50 EP 55 DI 10.1016/j.jastp.2006.07.015 PG 6 WC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences SC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences GA 141CC UT WOS:000244553100007 ER PT J AU Falconer, DA Moore, RL Gary, GA AF Falconer, D. A. Moore, R. L. Gary, G. A. TI Forecasting coronal mass ejections from line-of-sight magnetograms SO JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS LA English DT Article; Proceedings Paper CT Huntsville Workshop on Challenges to Modeling the Sun-Earth System CY OCT 18-22, 2004 CL Huntsville, AL DE CME; magnetogram; space weather; magnetic field; sun; corona ID FIELD AB We show that the length of strong-gradient, strong-field main neutral line, L-SGM, which can be measured from line-of-sight magnetograms such as from SOHO/MDI is both a measure of active-region nonpotentiality and a useful predictor of an active region's future Coronal mass ejections (CME) productivity. To demonstrate that L-SGM is a nonpotentiality measure, we show that it is strongly correlated with a direct measure of nonpotentiality. For an appropriate choice of a threshold value, an active region's measured L-SGM can be used as a predictor of whether the active region will produce a CME within a few days after the magnetogram. For our set of 36 Marshall Space Flight CentreMSFC vector magnetograms of bipolar active regions, L-SGM is found to have a success rate of 80% for prediction of CME productivity in the 0-2 day window. The development of L-SGM as a method of measuring nonpotentiality for forecasting large, fast CMEs from present space-based assets is of value to NASA's space exploration initiative (manned missions to the Moon and Mars). (c) 2006 Published by Elsevier Ltd. C1 NASA, George C Marshall Space Flight Ctr, Space Sci Branch, Huntsville, AL 35812 USA. RP Falconer, DA (reprint author), NASA, George C Marshall Space Flight Ctr, Space Sci Branch, XD12, Huntsville, AL 35812 USA. EM David.falconer@msfc.nasa.gov; ron.moore@nasa.gov; allen.gary@nasa.gov NR 15 TC 2 Z9 2 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1364-6826 J9 J ATMOS SOL-TERR PHY JI J. Atmos. Sol.-Terr. Phys. PD FEB PY 2007 VL 69 IS 1-2 BP 86 EP 90 DI 10.1016/j.jastp.2006.06.015 PG 5 WC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences SC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences GA 141CC UT WOS:000244553100011 ER PT J AU Wu, CC Wu, ST Dryer, M Fry, CD Berdichevsky, D Smith, Z Detman, T AF Wu, Chin-Chun Wu, S. T. Dryer, M. Fry, C. D. Berdichevsky, D. Smith, Z. Detman, T. TI The evolution of shocks near the surface of Sun during the epoch of Halloween 2003 SO JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS LA English DT Article; Proceedings Paper CT Huntsville Workshop on Challenges to Modeling the Sun-Earth System CY OCT 18-22, 2004 CL Huntsville, AL DE interplanetary shock; solar flare; coronal mass ejection; geomagnetic storm ID SLOW SHOCKS; SOLAR-WIND; HELIOSPHERE AB We use a one-dimensional, time-dependent adaptive grid MHD code to study the evolution of shocks (both slow and fast shocks) from the surface of the Sun through the heliosphere. In order to achieve the goal, we track a specific solar event's plasma and magnetic field output as it propagates into interplanetary space with a possible geoeffective consequence. We have chosen the famous event of the October/November ("Halloween 2003") epoch which produced two of the largest geomagnetic storms during solar cycle 23, followed by the arrivals of the shocks at Earth. These two geomagnetic storms are associated with two of these flares (X17/4B and X10/2B). Accordingly, four separate pressure pulses, at the appropriate times and with different strengths and duration, determined via a trial and error procedure, are introduced on the Sun to mimic the four flares. The results show that the simulated solar wind velocity temporal profiles successfully matched the observations at L1. The propagation speed of shock waves near the Sun also matched with the CME observations of SOHO/LASCO. The major objective, to demonstrate the detailed nature of interacting shocks and some of their products after origination from closely spaced solar events, is achieved. The evolution of both slow and fast shocks is also discussed in detail. (c) 2006 Elsevier Ltd. All rights reserved. C1 Univ Alabama, CSPAR, Huntsville, AL 35899 USA. Chinese Acad Sci, Lab Space Weather, Beijing, Peoples R China. NOAA, Space Environm Lab Ctr, SEC, Boulder, CO 80305 USA. Explorat Phys Int Inc, Huntsville, AL 35806 USA. L 3 Commun EER Syst Inc, Largo, MD 20774 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Wu, CC (reprint author), Univ Alabama, CSPAR, Huntsville, AL 35899 USA. EM wuc@cspar.uah.edu; wus@cspar.uah.edu; murray.dryer@noaa.gov; gfry@expi.com; dberdich@pop600.gsfc.nasa.gov; Zdenka.Smith@noaa.gov; Thomas.detman@noaa.gov RI xue, yansheng/A-9712-2012 NR 19 TC 4 Z9 5 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1364-6826 J9 J ATMOS SOL-TERR PHY JI J. Atmos. Sol.-Terr. Phys. PD FEB PY 2007 VL 69 IS 1-2 BP 91 EP 100 DI 10.1016/j.jastp.2006.07.014 PG 10 WC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences SC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences GA 141CC UT WOS:000244553100012 ER PT J AU Liemohn, MW Moore, TE Craven, PD AF Liemohn, M. W. Moore, T. E. Craven, P. D. TI Geospace activity dependence of cold, streaming ions in the near-Earth magnetotail SO JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS LA English DT Article; Proceedings Paper CT Huntsville Workshop on Challenges to Modeling the Sun-Earth System CY OCT 18-22, 2004 CL Huntsville, AL DE ionospheric ions; geomagnetic activity; ionosphere-magnetosphere coupling ID PLASMA SOURCE INSTRUMENT; DYNAMICS EXPERIMENT; GEOMAGNETIC STORM; POLAR WIND; SHEET; SOLAR; FIELD AB Results from a survey of the occurrence statistics of cold, streaming ion observations in the magnetotail lobes (lobal wind) in the Polar TIDE database are presented, considering lobal wind observation occurrence percentages during quiet and active times in geospace. It is found that lobal winds are observed more than half the time, even during magnetic storm conditions, and in quiet times they are seen nearly three-quarters of the time. They are seen throughout the magnetotail portion of the Polar orbit (apogee similar to 9 R-E near the magnetic equator in the tail during the survey epoch), and are regularly measured at all local times and at all latitudes within the surveyed domain. The beams flow along the magnetic field away from the ionosphere, and are often seen as bi-directional streams at lower magnetic latitudes, indicating that they are present on closed field lines as well as open ones. The commohness of these cold, streaming ions emphasizes the need for global magnetospheric modelers to account for this population. (c) 2006 Elsevier Ltd. All rights reserved. C1 Univ Michigan, Dept Atmospher Ocean & Space Sci, Ann Arbor, MI 48109 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NASA, George C Marshall Space Flight Ctr, Natl Space Sci & Technol Ctr, Huntsville, AL 35812 USA. RP Liemohn, MW (reprint author), Univ Michigan, Dept Atmospher Ocean & Space Sci, 2455 Hayward St, Ann Arbor, MI 48109 USA. EM liemohn@umich.edu RI Moore, Thomas/D-4675-2012; Liemohn, Michael/H-8703-2012 OI Moore, Thomas/0000-0002-3150-1137; Liemohn, Michael/0000-0002-7039-2631 NR 24 TC 0 Z9 0 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1364-6826 J9 J ATMOS SOL-TERR PHY JI J. Atmos. Sol.-Terr. Phys. PD FEB PY 2007 VL 69 IS 1-2 BP 135 EP 141 DI 10.1016/j.jastp.2006.07.018 PG 7 WC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences SC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences GA 141CC UT WOS:000244553100017 ER PT J AU Khazanov, GV Gamayunov, KV Gallagher, DL Spann, JF AF Khazanov, G. V. Gamayunov, K. V. Gallagher, D. L. Spann, J. F. TI Strong pitch-angle diffusion of ring current ions in geomagnetic storm-associated conditions SO JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS LA English DT Article; Proceedings Paper CT Huntsville Workshop on Challenges to Modeling the Sun-Earth System CY OCT 18-22, 2004 CL Huntsville, AL DE ring current; wave-particle interaction; strong pitch-angle diffusion; numerical modeling ID GREAT MAGNETIC STORM; CYCLOTRON WAVES; PROTON PRECIPITATION; SCATTERING; MODEL; PLASMASPHERE; MAGNETOTAIL; ATMOSPHERE; LOSSES; REGION AB Do electromagnetic ion cyclotron waves cause strong pitch-angle diffusion of the ring current (RC) ions? This question is the primary motivation of this paper and has been affirmatively answered from the theoretical point of view. The materials that are presented in the Results section show clear evidence that strong pitch-angle diffusion takes place in the inner magnetosphere indicating an important role of the wave-particle interaction in the magnetospheric RC formation. (c) 2006 Elsevier Ltd. All rights reserved. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35805 USA. RP Khazanov, GV (reprint author), NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35805 USA. EM george.khazanov@msfc.nasa.gov RI Gamayunov, Konstantin/A-8505-2009 OI Gamayunov, Konstantin/0000-0002-8768-8527 NR 34 TC 2 Z9 2 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1364-6826 J9 J ATMOS SOL-TERR PHY JI J. Atmos. Sol.-Terr. Phys. PD FEB PY 2007 VL 69 IS 1-2 BP 142 EP 150 DI 10.1016/j.jastp.2006.07.010 PG 9 WC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences SC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences GA 141CC UT WOS:000244553100018 ER PT J AU Bhardwaj, A Gladstone, GR Elsner, RF Ostgaard, N Waite, JH Cravens, TE Chang, SW Majeed, T Metzger, AE AF Bhardwaj, Anil Gladstone, G. Randall Elsner, Ronald F. Ostgaard, Nikolai Waite, J. Hunter, Jr. Cravens, Thomas E. Chang, Shen-Wu Majeed, Tariq Metzger, Albert E. TI First terrestrial soft X-ray auroral observation by the Chandra X-ray Observatory SO JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS LA English DT Article; Proceedings Paper CT Huntsville Workshop on Challenges to Modeling the Sun-Earth System CY OCT 18-22, 2004 CL Huntsville, AL DE auroral emissions; X-rays; Chandra X-ray Observatory; electron bremsstrahlung; Earth's upper atmosphere; Jupiter ID CUSP ENERGETIC IONS; ALTITUDE CUSP; BOW SHOCK; EMISSION; JUPITER; BREMSSTRAHLUNG; MAGNETOSPHERE; PRECIPITATION; ATMOSPHERE; ELECTRONS AB Northern auroral regions of Earth were imaged with energetic photons in the 0.1-10keV range using the HighResolution Camera (HRC-1) aboard the Chandra X-ray Observatory at 10 epochs (each similar to 20 min duration) between mid-December 2003 and mid-April 2004. These observations aimed at searching for Earth's soft (< 2keV) X-ray aurora in a comparative study with Jupiter's X-ray aurora, where a pulsating X-ray "hot-spot" has been previously observed by Chandra. The first Chandra soft X-ray observations of Earth's aurora show that it is highly variable (intense arcs, multiple arcs, diffuse patches, at times absent). In at least one of the observations an isolated blob of emission is observed near the expected cusp location. A fortuitous overflight of DMSP satellite F13 provided SSJ/4 energetic particle measurements above a bright arc seen by Chandra on 24 January 2004, 20:01-20:22 UT. A model of the emissions expected strongly suggests that the observed soft X-ray signal is bremsstrahlung and characteristic K-shell line emissions of nitrogen and oxygen in the atmosphere produced by electrons. (c) 2006 Elsevier Ltd. All rights reserved. C1 Vikram Sarabhai Space Ctr, Space Phys Lab, Trivandrum 695022, Kerala, India. SW Res Inst, Dept Space Sci, San Antonio, TX 78228 USA. Univ Bergen, Dept Phys & Technol, N-5007 Bergen, Norway. Univ Michigan, Dept Atmospher Ocean & Space Sci, Ann Arbor, MI 48109 USA. Univ Kansas, Dept Phys & Astron, Lawrence, KS 66045 USA. Univ Alabama, NSSTC, Huntsville, AL 35805 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Bhardwaj, A (reprint author), Vikram Sarabhai Space Ctr, Space Phys Lab, Trivandrum 695022, Kerala, India. EM Anil_Bhardwaj@vssc.gov.in OI Bhardwaj, Anil/0000-0003-1693-453X NR 43 TC 9 Z9 9 U1 1 U2 3 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1364-6826 J9 J ATMOS SOL-TERR PHY JI J. Atmos. Sol.-Terr. Phys. PD FEB PY 2007 VL 69 IS 1-2 BP 179 EP 187 DI 10.1016/j.jastp.2006.07.011 PG 9 WC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences SC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences GA 141CC UT WOS:000244553100023 ER PT J AU Charlton, AJ Polvani, LM Perlwitz, J Sassi, F Manzini, E Shibata, K Pawson, S Nielsen, JE Rind, D AF Charlton, Andrew J. Polvani, Lorenzo M. Perlwitz, Judith Sassi, Fabrizio Manzini, Elisa Shibata, Kiyotaka Pawson, Steven Nielsen, J. Eric Rind, David TI A new look at stratospheric sudden warmings. Part II: Evaluation of numerical model simulations SO JOURNAL OF CLIMATE LA English DT Article ID GENERAL-CIRCULATION MODEL; CHEMISTRY-CLIMATE MODELS; SEA-SURFACE TEMPERATURE; DOUBLED CO2 CLIMATE; MIDDLE ATMOSPHERE; INTERCOMPARISON PROJECT; NORTHERN-HEMISPHERE; WAVE ACTIVITY; OZONE LOSSES; OSCILLATION AB The simulation of major midwinter stratospheric sudden warmings (SSWs) in six stratosphere-resolving general circulation models (GCMs) is examined. The GCMs are compared to a new climatology of SSWs, based on the dynamical characteristics of the events. First, the number, type, and temporal distribution of SSW events are evaluated. Most of the models show a lower frequency of SSW events than the climatology, which has a mean frequency of 6.0 SSWs per decade. Statistical tests show that three of the six models produce significantly fewer SSWs than the climatology, between 1.0 and 2.6 SSWs per decade. Second, four process-based diagnostics are calculated for all of the SSW events in each model. It is found that SSWs in the GCMs compare favorably with dynamical benchmarks for SSW established in the first part of the study. These results indicate that GCMs are capable of quite accurately simulating the dynamics required to produce SSWs, but with lower frequency than the climatology. Further dynamical diagnostics hint that, in at least one case, this is due to a lack of meridional heat flux in the lower stratosphere. Even though the SSWs simulated by most GCMs are dynamically realistic when compared to the NCEP-NCAR reanalysis, the reasons for the relative paucity of SSWs in GCMs remains an important and open question. C1 Columbia Univ, Dept Appl Phys & Appl Math, New York, NY USA. Columbia Univ, Dept Earth & Environm Sci, New York, NY USA. Univ Colorado, Cooperat Inst Res Environm Sci, Clin Diagnost Ctr, Boulder, CO 80309 USA. NOAA, Earth Syst Res Lab, Div Phys Sci, Boulder, CO 80309 USA. Natl Ctr Atmospher Res, Boulder, CO 80307 USA. Ist Nazl Geofis & Vulcanol, Bologna, Italy. Meteorol Res Inst, Tsukuba, Ibaraki 305, Japan. NASA, Goddard Space Flight Ctr, Global Modeling & Assimilat Off, Greenbelt, MD 20771 USA. NASA, Goddard Inst Space Studies, New York, NY 10025 USA. RP Charlton, AJ (reprint author), Univ Reading, Dept Meteorol, Reading RG6 6BB, Berks, England. EM a.j.charlton@reading.ac.uk RI Perlwitz, Judith/B-7201-2008; Manzini, Elisa/H-5760-2011; Charlton-Perez, Andrew/F-4079-2010; Pawson, Steven/I-1865-2014; OI Perlwitz, Judith/0000-0003-4061-2442; Charlton-Perez, Andrew/0000-0001-8179-6220; Pawson, Steven/0000-0003-0200-717X; Sassi, Fabrizio/0000-0002-9492-7434 NR 43 TC 76 Z9 80 U1 0 U2 13 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8755 EI 1520-0442 J9 J CLIMATE JI J. Clim. PD FEB 1 PY 2007 VL 20 IS 3 BP 470 EP 488 DI 10.1175/JCLI3994.1 PG 19 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 134OP UT WOS:000244093000006 ER PT J AU Loeb, NG Wielicki, BA Su, WY Loukachine, K Sun, WB Wong, T Priestley, KJ Matthews, G Miller, WF Davies, R AF Loeb, Norman G. Wielicki, Bruce A. Su, Wenying Loukachine, Konstantin Sun, Wenbo Wong, Takmeng Priestley, Kory J. Matthews, Grant Miller, Walter F. Davies, R. TI Multi-instrument comparison of top-of-atmosphere reflected solar radiation SO JOURNAL OF CLIMATE LA English DT Article ID IMAGING SPECTRORADIOMETER MISR; ANGULAR-DISTRIBUTION MODELS; ENERGY SYSTEM INSTRUMENT; PART I; DECADAL VARIABILITY; FLUX ESTIMATION; INPUT DATA; DATA SETS; SATELLITE; CLOUDS AB Observations from the Clouds and the Earth's Radiant Energy System (CERES), Moderate Resolution Imaging Spectroradiometer (MODIS), Multiangle Imaging Spectroradiometer (MISR), and Sea-Viewing Wide-Field-of-View Sensor (SeaWiFS) between 2000 and 2005 are analyzed in order to determine if these data are meeting climate accuracy goals recently established by the climate community. The focus is primarily on top-of-atmosphere (TOA) reflected solar radiances and radiative fluxes. Direct comparisons of nadir radiances from CERES, MODIS, and MISR aboard the Terra satellite reveal that the measurements from these instruments exhibit a year-to-year relative stability of better than 1%, with no systematic change with time. By comparison, the climate requirement for the stability of visible radiometer measurements is 1% decade(-1). When tropical ocean monthly anomalies in shortwave (SW) TOA radiative fluxes from CERES on Terra are compared with anomalies in Photosynthetically Active Radiation (PAR) from SeaWiFS-an instrument whose radiance stability is better than 0.07% during its first six years in orbit-the two are strongly anticorrelated. After scaling the SeaWiFS anomalies by a constant factor given by the slope of the regression line fit between CERES and SeaWiFS anomalies, the standard deviation in the difference between monthly anomalies from the two records is only 0.2 W m(-2), and the difference in their trend lines is only 0.02 +/- 0.3 W m(-2) decade(-1), approximately within the 0.3 W m(-2) decade(-1) stability requirement for climate accuracy. For both the Tropics and globe, CERES Terra SW TOA fluxes show no trend between March 2000 and June 2005. Significant differences are found between SW TOA flux trends from CERES Terra and CERES Aqua between August 2002 and March 2005. This discrepancy is due to uncertainties in the adjustment factors used to account for degradation of the CERES Aqua optics during hemispheric scan mode operations. Comparisons of SW TOA flux between CERES Terra and the International Satellite Cloud Climatology Project (ISCCP) radiative flux profile dataset (FD) RadFlux product show good agreement in monthly anomalies between January 2002 and December 2004, and poor agreement prior to this period. Commonly used statistical tools applied to the CERES Terra data reveal that in order to detect a statistically significant trend of magnitude 0.3 W m(-2) decade(-1) in global SW TOA flux, approximately 10 to 45 yr of data are needed. This assumes that CERES Terra instrument calibration remains highly stable, long-term climate variability remains constant, and the Terra spacecraft has enough fuel to last 15 yr. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. Hampton Univ, Ctr Atmospher Sci, Hampton, VA 23668 USA. Sci Applicat Int Corp, Hampton, VA USA. Analyt Serv & Mat Inc, Hampton, VA 23666 USA. CALTECH, Jet Propuls Lab, Pasadena, CA 91125 USA. RP Loeb, NG (reprint author), NASA, Langley Res Ctr, Mail Stop 420, Hampton, VA 23681 USA. EM n.g.loeb@larc.nasa.gov RI Davies, Roger/D-4296-2009; Richards, Amber/K-8203-2015 OI Davies, Roger/0000-0002-2991-0409; NR 39 TC 54 Z9 54 U1 0 U2 8 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8755 EI 1520-0442 J9 J CLIMATE JI J. Clim. PD FEB 1 PY 2007 VL 20 IS 3 BP 575 EP 591 DI 10.1175/JCLI4018.1 PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 134OP UT WOS:000244093000013 ER PT J AU Sulikowski, JA Driggers, WB Ford, TS Boonstra, RK Carlson, JK AF Sulikowski, J. A. Driggers, W. B., III Ford, T. S. Boonstra, R. K. Carlson, J. K. TI Reproductive cycle of the blacknose shark Carcharhinus acronotus in the Gulf of Mexico SO JOURNAL OF FISH BIOLOGY LA English DT Article DE blacknose shark; Carcharhinidae; elasmobranch; reproduction ID WESTERN NORTH-ATLANTIC; RHIZOPRIONODON-TERRAENOVAE RICHARDSON; SOUTHEASTERN UNITED-STATES; LIFE-HISTORY; LEUCORAJA-OCELLATA; GONAD DEVELOPMENT; FINETOOTH SHARK; SHARPNOSE SHARK; COASTAL WATERS; WINTER SKATE AB The reproductive periodicity of blacknose sharks Carcharhinus acronotus in the northern Gulf of Mexico was determined by examining reproductive tissues from specimens collected monthly from 2002 to 2005. Monthly changes in shell gland mass, right ovary mass and ovarian follicle diameter were assessed for 74 mature females. Temporal changes in testes mass, testes width and proportion of mature spermatocysts were examined for 64 mature males. Trends in female reproductive tissues suggested an annual peak in reproductive activity during June and July, while trends in male variables suggested an annual reproductive peak during May and June. Although male and female reproductive activity peaked in different months, a strong synchronicity existed between the proportion of mature spermatocysts and the diameter of the largest ovarian follicle. Based on these results, the mating season of blacknose sharks lasts from mid-May to July in the Gulf of Mexico. Maximum embryo sizes were observed in May, which suggested that partition occurs during late May or early June. Results indicate that blacknose sharks have a clearly defined annual cycle in the Gulf of Mexico. This conclusion is further supported by the complete absence of gravid females without vitellogenic ovarian follicles among all mature females examined. C1 Univ Florida, Florida Museum Nat Hist, Florida Program Shark Res, Gainesville, FL 32611 USA. Mississippi Labs, SE Fisheries Sci Ctr, Natl Marine Fisheries Serv, Pascagoula, MS 39568 USA. Panama City Lab, SE Fisheries Sci Ctr, Natl Marine Fisheries Serv, Panama City, FL 32408 USA. RP Sulikowski, JA (reprint author), Univ New England, Ctr Marine Sci, 11 Hills Beach Rd, Biddeford, ME 04005 USA. EM jsulikowski@une.edu NR 42 TC 10 Z9 11 U1 0 U2 13 PU BLACKWELL PUBLISHING PI OXFORD PA 9600 GARSINGTON RD, OXFORD OX4 2DQ, OXON, ENGLAND SN 0022-1112 J9 J FISH BIOL JI J. Fish Biol. PD FEB PY 2007 VL 70 IS 2 BP 428 EP 440 DI 10.1111/j.1095-8649.2007.01314.x PG 13 WC Fisheries; Marine & Freshwater Biology SC Fisheries; Marine & Freshwater Biology GA 132XR UT WOS:000243976700008 ER PT J AU Moss, JH Beauchamp, DA AF Moss, J. H. Beauchamp, D. A. TI Functional response of juvenile pink and chum salmon: effects of consumer size and two types of zooplankton prey SO JOURNAL OF FISH BIOLOGY LA English DT Article DE chum salmon; copepods; functional response; mysids; pink salmon ID KOKANEE ONCORHYNCHUS-NERKA; DIEL VERTICAL MIGRATION; PLANKTIVOROUS FISH; FEEDING-BEHAVIOR; FORAGING MODEL; GROWTH-RATE; BODY SIZE; PREDATION; MORTALITY; LAKE AB Feeding rate experiments were conducted for pink salmon Oncorhynchus gorbuscha fry [mean fork length (L-F) 39 mm], juveniles (103-104 mm L-F) and juvenile chum salmon Oncorhynchus keta (106-107 mm L-F). Fishes were presented with small copepod (Tisbi sp.) or larger mysid shrimp (Mysidopsis bahia) prey at varying densities ranging from 1 to 235 prey l(-1) in feeding rate experiments conducted at water temperatures ranging from 10.5 to 12.0 degrees C under high light levels and low turbidity conditions. Juvenile pink and chum salmon demonstrated a type II functional response to mysid and copepod prey. Mysid prey was readily selected by both species whereas the smaller bodied copepod prey was not. When offered copepods, pink salmon fry fed at a higher maximum consumption rate (2.5 copepods min(-1)) than larger juvenile pink salmon (0.4 copepods min(-1)), whereas larger juvenile chum salmon exhibited the highest feeding rate (3.8 copepods min(-1)). When feeding on mysids, the maximum feeding rate for larger juvenile pink (12.3 mysids min(-1)) and chum (11.5 mysids min(-1)) salmon were similar in magnitude, and higher than feeding rates on copepods. Functional response models parameterized for specific sizes of juvenile salmon and zooplankton prey provide an important tool for linking feeding rates to ambient foraging conditions in marine environments, and can enable mechanistic predictions for how feeding and growth should respond to spatial-temporal variability in biological and physical conditions during early marine life stages. C1 NOAA, Natl Marine Fisheries Serv, Auke Bay Lab, Juneau, AK 99801 USA. Univ Washington, Sch Aquat & Fisheries Sci, US Geol Survey, Washington Cooperat Fish & Wildlife Res Unit, Seattle, WA 98195 USA. RP Moss, JH (reprint author), NOAA, Natl Marine Fisheries Serv, Auke Bay Lab, 11305 Glacier Hwy, Juneau, AK 99801 USA. EM jamal.moss@noaa.gov NR 49 TC 8 Z9 8 U1 1 U2 7 PU BLACKWELL PUBLISHING PI OXFORD PA 9600 GARSINGTON RD, OXFORD OX4 2DQ, OXON, ENGLAND SN 0022-1112 J9 J FISH BIOL JI J. Fish Biol. PD FEB PY 2007 VL 70 IS 2 BP 610 EP 622 DI 10.1111/j.1095-8649.2007.01340.x PG 13 WC Fisheries; Marine & Freshwater Biology SC Fisheries; Marine & Freshwater Biology GA 132XR UT WOS:000243976700022 ER PT J AU Borsa, AA Minster, JB Bills, BG Fricker, HA AF Borsa, Adrian A. Minster, Jean-Bernard Bills, Bruce G. Fricker, Helen A. TI Modeling long-period noise in kinematic GPS applications SO JOURNAL OF GEODESY LA English DT Article DE global positioning system (GPS); noise; kinematic GPS; inverse theory; salar de Uyuni; ICESat ID GLOBAL POSITIONING SYSTEM; LASER ALTIMETRY; CRUSTAL DEFORMATION; CALIFORNIA; RESOLUTION; VALLEY AB We develop and test an algorithm for modeling and removing elevation error in kinematic GPS trajectories in the context of a kinematic GPS survey of the salar de Uyuni, Bolivia. Noise in the kinematic trajectory ranges over 15 cm and is highly autocorrelated, resulting in significant contamination of the topographic signal. We solve for a noise model using crossover differences at trajectory intersections as constraints in a least-squares inversion. Validation of the model using multiple realizations of synthetic/simulated noise shows an average decrease in root-mean-square-error (RMSE) by a factor of four. Applying the model to data from the salar de Uyuni survey, we find that crossover differences drop by a factor of eight (from an RMSE of 5.6 to 0.7 cm), and previously obscured topographic features are revealed in a plan view of the corrected trajectory. We believe that this algorithm can be successfully adapted to other survey methods that employ kinematic GPS for positioning. C1 Univ Calif San Diego, Scripps Inst Oceanog, Inst Geophys & Planetary Phys, La Jolla, CA 92093 USA. NASA, Goddard Space Flight Ctr, Planetary Geodynam Lab, Greenbelt, MD 20771 USA. RP Borsa, AA (reprint author), Univ Calif San Diego, Scripps Inst Oceanog, Inst Geophys & Planetary Phys, 9500 Gilman Dr,Mailstop 0225, La Jolla, CA 92093 USA. EM aborsa@ucsd.edu RI Bills, Bruce/C-1156-2008; OI Minster, Jean Bernard/0000-0003-1268-5177 NR 30 TC 7 Z9 7 U1 0 U2 5 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0949-7714 EI 1432-1394 J9 J GEODESY JI J. Geodesy PD FEB PY 2007 VL 81 IS 2 BP 157 EP 170 DI 10.1007/s00190-006-0097-x PG 14 WC Geochemistry & Geophysics; Remote Sensing SC Geochemistry & Geophysics; Remote Sensing GA 130NB UT WOS:000243805200006 ER PT J AU Huffman, GJ Adler, RF Bolvin, DT Gu, GJ Nelkin, EJ Bowman, KP Hong, Y Stocker, EF Wolff, DB AF Huffman, George J. Adler, Robert F. Bolvin, David T. Gu, Guojun Nelkin, Eric J. Bowman, Kenneth P. Hong, Yang Stocker, Erich F. Wolff, David B. TI The TRMM multisatellite precipitation analysis (TMPA): Quasi-global, multiyear, combined-sensor precipitation estimates at fine scales SO JOURNAL OF HYDROMETEOROLOGY LA English DT Article ID MICROWAVE SOUNDING UNIT; PASSIVE MICROWAVE; TROPICAL RAINFALL; RESOLUTION; DATASET; SYSTEM; CLOUD; ALGORITHMS AB The Tropical Rainfall Measuring Mission (TRMM) Multisatellite Precipitation Analysis (TMPA) provides a calibration-based sequential scheme for combining precipitation estimates from multiple satellites, as well as gauge analyses where feasible, at fine scales (0.25 degrees x 0.25 degrees and 3 hourly). TMPA is available both after and in real time, based on calibration by the TRMM Combined Instrument and TRMM Microwave Imager precipitation products, respectively. Only the after-real-time product incorporates gauge data at the present. The dataset covers the latitude band 50 degrees N-S for the period from 1998 to the delayed present. Early validation results are as follows: the TMPA provides reasonable performance at monthly scales, although it is shown to have precipitation rate-dependent low bias due to lack of sensitivity to low precipitation rates over ocean in one of the input products [ based on Advanced Microwave Sounding Unit-B (AMSU-B)]. At finer scales the TMPA is successful at approximately reproducing the surface observation-based histogram of precipitation, as well as reasonably detecting large daily events. The TMPA, however, has lower skill in correctly specifying moderate and light event amounts on short time intervals, in common with other finescale estimators. Examples are provided of a flood event and diurnal cycle determination. C1 NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. Sci Syst & Applicat Inc, Lanham, MD USA. Univ Maryland Baltimore Cty, Goddard Earth Sci & Technol Ctr, Baltimore, MD 21228 USA. Texas A&M Univ, College Stn, TX USA. NASA, Goddard Space Flight Ctr, Global Change Data Ctr, Greenbelt, MD 20771 USA. RP Huffman, GJ (reprint author), NASA, Goddard Space Flight Ctr, Atmospheres Lab, Code 613-1, Greenbelt, MD 20771 USA. EM huffman@agnes.gsfc.nasa.gov RI Hong, Yang/D-5132-2009; Bowman, Kenneth/A-1345-2012; Wolff, David/H-5502-2012; Huffman, George/F-4494-2014 OI Hong, Yang/0000-0001-8720-242X; Bowman, Kenneth/0000-0002-2667-8632; Huffman, George/0000-0003-3858-8308 NR 39 TC 2111 Z9 2199 U1 26 U2 191 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 1525-755X J9 J HYDROMETEOROL JI J. Hydrometeorol. PD FEB PY 2007 VL 8 IS 1 BP 38 EP 55 DI 10.1175/JHM560.1 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 142EL UT WOS:000244632100003 ER PT J AU Alonge, CJ Mohr, KI Tao, WK AF Alonge, Charles J. Mohr, Karen I. Tao, Wei-Kuo TI Numerical studies of wet versus dry soil regimes in the West African Sahel SO JOURNAL OF HYDROMETEOROLOGY LA English DT Article ID BOUNDARY-LAYER; EASTERLY JET; LAND-SURFACE; TIGER BUSH; DIURNAL CYCLE; SQUALL LINES; HAPEX-SAHEL; LARGE-SCALE; PRECIPITATION; CLIMATE AB The West African Sahel lies between the wet, humid equatorial zone of Africa to the south and the Sahara Desert to the north. This topography results in a strong north-south precipitation gradient. A coupled land-atmosphere (cloud resolving) model and observed data from the Hydrological Atmospheric Pilot Experiment in the Sahel were used to simulate both wet and dry soil moisture regimes. There are two case studies-one characterized by convective precipitation, the other by fair weather. In both of the case studies, evapotranspiration from the tiger bush land cover was noticeably larger in the wet soil moisture regime. The increase in latent heat flux was the key factor in creating a boundary layer that was more favorable to late-afternoon deep convection in the wet regime. Differences in boundary layer growth and development between the case studies suggested a more important role for the land surface in fair weather environments versus convective precipitation environments. C1 SUNY Albany, Dept Earth & Atmospher Sci, Albany, NY 12222 USA. NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. RP Mohr, KI (reprint author), SUNY Albany, Dept Earth & Atmospher Sci, Albany, NY 12222 USA. EM mohr@atmos.albany.edu RI Mohr, Karen/E-4331-2012 NR 40 TC 21 Z9 23 U1 0 U2 4 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 1525-755X J9 J HYDROMETEOROL JI J. Hydrometeorol. PD FEB PY 2007 VL 8 IS 1 BP 102 EP 116 DI 10.1175/JHM559.1 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 142EL UT WOS:000244632100007 ER PT J AU Kisiel, Z Pszczolkowski, L Bialkowska-Jaworska, E Charnley, SB AF Kisiel, Zbigniew Pszczolkowski, Lech Bialkowska-Jaworska, Ewa Charnley, Steven B. TI The millimeter wave rotational spectrum of pyruvic acid SO JOURNAL OF MOLECULAR SPECTROSCOPY LA English DT Article DE rotational spetroscopy; millimeter-wave spectroscopy; internal rotation; excited vibrational states; astrophysics ID HOT MOLECULAR CORES; INTERNAL-ROTATION; MICROWAVE-SPECTRUM; LABORATORY ASSIGNMENTS; ORGANIC-COMPOUNDS; DIETHYL-ETHER; METEORITES; SPECTROSCOPY; PREDICTIONS; BARRIER AB The rotational spectrum of pyruvic acid has been investigated for the first time in the millimeter-wave region, at 160-314 GHz, and also in supersonic expansion, at 10-17.4 GHz. The analysis of the broadband spectra recorded in this work was carried out with the newly developed AABS software package for Assignment and Analysis of Broadband Spectra, and precise spectroscopic constants are reported for the ground state, the first excited state of the low-frequency skeletal torsional mode v(24), and the first excited state of the methyl torsional mode nu(23). Limited results have also been obtained for several higher excited states. The dataset for the ground state currently exceeds 1500 lines and for both the A and E internal rotor sublevels spans the complete range of values of K(a) at the mid values of J for the measured transitions. The results were analysed with three freely available computer programs employing different strategies for dealing with internal rotation and a comparative discussion of their merits is made. (c) 2007 Elsevier Inc. All rights reserved. C1 Polish Acad Sci, Inst Phys, PL-02668 Warsaw, Poland. NASA, Ames Res Ctr, Space Sci & Astrobiol Div, Moffett Field, CA 94035 USA. RP Kisiel, Z (reprint author), Polish Acad Sci, Inst Phys, Al Lotnikow 32-46, PL-02668 Warsaw, Poland. EM kisiel@ifpan.edu.pl RI Charnley, Steven/C-9538-2012; Kisiel, Zbigniew/K-8798-2016; Bialkowska-Jaworska, Ewa/R-9282-2016; Pszczolkowski, Lech/S-3018-2016 OI Kisiel, Zbigniew/0000-0002-2570-3154; NR 50 TC 20 Z9 20 U1 1 U2 9 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0022-2852 J9 J MOL SPECTROSC JI J. Mol. Spectrosc. PD FEB PY 2007 VL 241 IS 2 BP 220 EP 229 DI 10.1016/j.jms.2006.12.011 PG 10 WC Physics, Atomic, Molecular & Chemical; Spectroscopy SC Physics; Spectroscopy GA 139WG UT WOS:000244462700011 ER PT J AU Yang, YL Gupta, MC Dudley, KL Lawrence, RW AF Yang, Yonglai Gupta, Mool C. Dudley, Kenneth L. Lawrence, Roland W. TI Electromagnetic interference shielding characteristics of carbons nanofiber-polymer composites SO JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY LA English DT Article DE carbon nanofibers; polymer; composites; EMI shielding ID BUTADIENE-STYRENE COMPOSITES; ELECTRICAL-PROPERTIES; CONDUCTING POLYMERS; MATRIX COMPOSITES; MULTILAYER FILMS; NANOTUBES; NANOCOMPOSITES; CATALYST; FIBERS; MIXTURES AB Electromagnetic interference (EMI) shielding characteristics of carbon nanofiber-polystyrene composites were investigated in the frequency range of 12.4-18 GHz (Ku-band). It was observed that the shielding effectiveness of such composites was frequency independent, and increased with increasing carbon nanofiber loading within Ku-band. The experimental data exhibited that the shielding effectiveness of the polymer composite containing 20 wt% carbon nanofibers could reach more than 36 dB in the measured frequency region, indicating such composites can be applied to the potential EMI shielding materials. In addition, the results showed that the contribution of reflection to the EMI shielding effectiveness was much larger than that of absorption, implying the primary EMI shielding mechanism of such composites was reflection of electromagnetic radiation within Ku-band. C1 Univ Virginia, Charles L Brown Dept Elect & Comp Engn, Charlottesville, VA 22904 USA. NASA, Langley Res Ctr, Electromagnet & Sensors Res Branch, Hampton, VA 23681 USA. RP Gupta, MC (reprint author), Univ Virginia, Charles L Brown Dept Elect & Comp Engn, Charlottesville, VA 22904 USA. NR 32 TC 23 Z9 24 U1 1 U2 14 PU AMER SCIENTIFIC PUBLISHERS PI STEVENSON RANCH PA 25650 NORTH LEWIS WAY, STEVENSON RANCH, CA 91381-1439 USA SN 1533-4880 J9 J NANOSCI NANOTECHNO JI J. Nanosci. Nanotechnol. PD FEB PY 2007 VL 7 IS 2 BP 549 EP 554 DI 10.1166/jnn.2007.113 PG 6 WC Chemistry, Multidisciplinary; Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Physics, Applied; Physics, Condensed Matter SC Chemistry; Science & Technology - Other Topics; Materials Science; Physics GA 126LR UT WOS:000243514900024 PM 17450793 ER PT J AU Jalbout, AF Hameed, AJ Trzaskowski, B AF Jalbout, Abraham F. Hameed, Ali Jameel Trzaskowski, Bartosz TI Study of the structural and electronic properties of 1-(4,5 and 6-selenenyl derivatives-3-formyl-phenyl) pyrrolidinofullerenes SO JOURNAL OF ORGANOMETALLIC CHEMISTRY LA English DT Article DE fullerene; selenium; organoselenium compounds; fulleropyrrolidine; DFT ID IODOTHYRONINE DEIODINASE; FULLERENE DERIVATIVES; HIV-1 PROTEASE; FULLEROPYRROLIDINES; INHIBITION; DENSITY; CLONING; CDNA AB A series of 1-(4, 5 and 6-selenenyl derivatives-3-formyl-phenyl) pyrrolidinofullerenes molecules C(60)-C(2)H(4)N-[3-(CHO)C(6)H(3)SeX] were investigated theoretically by performing Density Functional Theory calculations at the B3LYP/3-21G* level of the theory. The substituents include: X = CN, CH(2)CH(NH(2))CO(2)H and CH(2)CH(2)CH(NH(2))CO(2)H. We have selected these substituents to be in ortho, meta and para positions with relation to formyl group in order to show the effect of such structural change on the electronic properties of the molecules. The theoretical IR spectra, physical, chemical and thermodynamics properties of the molecules studied are obtained and discussed. (c) 2006 Elsevier B.V. All rights reserved. C1 Univ Nacl Autonoma Mexico, Inst Chem, Mexico City 04510, DF, Mexico. Univ Basrah, Coll Sci, Dept Chem, Basrah, Iraq. Univ Arizona, Dept Chem, NASA, Astrobiol Inst, Tucson, AZ 85721 USA. RP Jalbout, AF (reprint author), Univ Nacl Autonoma Mexico, Inst Chem, Mexico City 04510, DF, Mexico. EM ajalbout@u.arizona.edu; alijamail2003@yahoo.com RI Trzaskowski, Bartosz/B-1881-2008 OI Trzaskowski, Bartosz/0000-0003-2385-1476 NR 35 TC 10 Z9 10 U1 0 U2 1 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0022-328X J9 J ORGANOMET CHEM JI J. Organomet. Chem. PD FEB 1 PY 2007 VL 692 IS 5 BP 1039 EP 1047 DI 10.1016/j.jorganchem.2006.10.068 PG 9 WC Chemistry, Inorganic & Nuclear; Chemistry, Organic SC Chemistry GA 138YQ UT WOS:000244399600015 ER PT J AU Bozzolo, G Garces, JE AF Bozzolo, G. Garces, J. E. TI Atomistic modeling of multicomponent systems SO JOURNAL OF PHASE EQUILIBRIA AND DIFFUSION LA English DT Article; Proceedings Paper CT Symposium on Multi-Component Alloy Thermodynamics CY MAR 12-16, 2006 CL San Antonio, TX SP TMS, EMPMD, SMD, Alloy Phase Comm DE computational statistics; first principles; interdiffusion; intermetallics; metallic alloys; modeling; Monte Carlo simulations ID HIGH-TEMPERATURE ALLOYS; NI-BASE SUPERALLOY; AL-RU SYSTEM; MECHANICAL-PROPERTIES; SITE-OCCUPANCIES; SUBSTITUTIONAL SOLUTES; IRRADIATION BEHAVIOR; COHESIVE PROPERTIES; DISPERSION FUEL; PHASE AB The need to accelerate materials design programs based on economical and efficient modeling techniques provides the framework for the introduction of approximations in otherwise rigorous theoretical schemes. Several quantum approximate methods have been introduced through the years, bringing new opportunities for the efficient understanding of complex multicomponent alloys at the atomic level. As a promising example of the role that these methods might have in the development of complex systems, in this work we discuss the Bozzolo-Ferrante-Smith (BITS) method for alloys and its application to a variety of multicomponent systems for a detailed analysis of their defect and phase structure and their properties. Examples include the study of the phase structure of new Ru-rich Ni-base superalloys, the role of multiple alloying additions in high temperature intermetallic alloys, and interfacial phenomena in nuclear materials, highlighting the benefits that can be obtained from introducing simple modeling techniques to the investigation of complex systems. C1 Ohio Aerospace Inst, Cleveland, OH 44142 USA. NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. Ctr Atom Bariloche, RA-8400 San Carlos De Bariloche, Rio Negro, Argentina. RP Bozzolo, G (reprint author), Ohio Aerospace Inst, 22800 Cedar Point Rd, Cleveland, OH 44142 USA. EM GuillermoBozzolo@oai.org NR 50 TC 0 Z9 0 U1 0 U2 3 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 1547-7037 EI 1863-7345 J9 J PHASE EQUILIB DIFF JI J. Phase Equilib. Diffus. PD FEB PY 2007 VL 28 IS 1 BP 23 EP 37 DI 10.1007/s11669-006-9001-x PG 15 WC Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Chemistry; Materials Science; Metallurgy & Metallurgical Engineering GA 183AK UT WOS:000247544900004 ER PT J AU Copland, E AF Copland, Evan TI Partial thermodynamic properties of gamma '-(Ni,Pt)(3)Al in the Ni-Al-Pt system SO JOURNAL OF PHASE EQUILIBRIA AND DIFFUSION LA English DT Article; Proceedings Paper CT Symposium on Multi-component Alloy Thermodynamics CY MAR 12-16, 2006 CL San Antonio, TX SP TMS, EMPMD, SMD, Alloy Phase Comm DE diffusion; ternary phase diagram; thermodynamics; vapor pressure ID TEMPERATURE MASS-SPECTROMETRY; PLATINUM; ALLOYS; INTERDIFFUSION; CONSTRAINTS; BEHAVIOR; CELL AB Measurements were made to determine how Pt influences the partial thermodynamic properties of Al and Ni in gamma'-(Ni,Pt)(3)Al and liquid in the Ni-Al-Pt system. The activities of All and Ni were measured with a multiple effusion-cell mass spectrometer (multi-cell KEMS). For a constant X-Al = 0.24, adding Pt, from X-Pt = 0.02-0.25, reduces a(Al) almost an order of magnitude, from 2 x 10(-4) to 2 X 10(-5), at 1560 K. This occurred for Delta H-m(Al) of -203 +/- 10 kJ mol(-1) and the a(Al) decrease was due to Delta n (S) over bar (Al) increasing from -60 to -40 J mol(-1) K-1 with Pt addition. The large negative Delta(m)(H) over bar (Al) and Delta(m)(S) over bar (Al) indicate Al-atoms are highly ordered in gamma'-(Ni,Pt)(3)Al. Nickel activity, a(Ni), remained essentially constant, similar to 0.7, indicating an increasing ternary interaction between Ni-atoms and (Al + Pt)-atoms with Pt addition, where gamma(Ni) increased from about 0.7 to 1.2. This is supported by A H(Ni) in the range 6.1-7.1 +/- 1.5 kJ mol(-1) at 1520 K, and a positive Delta n (S) over bar (xs)(Ni), which suggest disorder on the Ni-lattice. For a consistent X-Al = 0.27, adding Pt, from X-Pt = 0.10-0.25, also reduces a(Al) but only by a factor of about 3, while a(Ni) remained essentially constant, with gamma(Ni) increasing from about 0.7 to 0.95. A dramatic change in the mixing behavior was observed between the X-Al = 0.24 and 0.27 series of alloys, where AnH(Al) and Delta(m)(S) over bar (Al) are seen to increase about 50 kJ mol(-1) and 20 J mol(-1) K-1 at T = 1566 K, respectively. In contrast, Delta(m)(H) over bar (Ni) decreased about 16 kJ mol(-1) at T = 1520 K and Delta(m)(S) over bar xs(Ni) changed from a positive to a negative value. C1 Case Western Reserve Univ, NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Copland, E (reprint author), Case Western Reserve Univ, NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. EM evan.copland@grc.nasa.gov NR 26 TC 17 Z9 17 U1 1 U2 9 PU ASM INTERNATIONAL PI MATERIALS PARK PA SUBSCRIPTIONS SPECIALIST CUSTOMER SERVICE, MATERIALS PARK, OH 44073-0002 USA SN 1547-7037 J9 J PHASE EQUILIB DIFF JI J. Phase Equilib. Diffus. PD FEB PY 2007 VL 28 IS 1 BP 38 EP 48 DI 10.1007/s11669-006-9004-7 PG 11 WC Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Chemistry; Materials Science; Metallurgy & Metallurgical Engineering GA 183AK UT WOS:000247544900005 ER PT J AU Fleming, ED Bebout, BM Castenholz, RW AF Fleming, Erich D. Bebout, Brad M. Castenholz, Richard W. TI Effects of salinity and light intensity on the resumption of photosynthesis in rehydrated cyanobacterial mats from Baja California Sur, Mexico SO JOURNAL OF PHYCOLOGY LA English DT Article DE desiccation; Lyngbya aestuarii; PAM fluorometry; photosynthesis; rehydration; salt stress ID NOSTOC-COMMUNE CYANOBACTERIA; BLUE-GREEN-ALGAE; TERRESTRIAL CYANOBACTERIUM; CHLOROPHYLL FLUORESCENCE; SALT STRESS; MICROBIAL MATS; FLAGELLIFORME CYANOPHYCEAE; DESICCATION TOLERANCE; WATER-STRESS; RECOVERY AB Lyngbya mats in the intertidal of the Laguna Ojo de Liebre are metabolically active for only a few days every 2 weeks during spring tides, with environmental conditions varying greatly during these periods of hydration. Pulse amplitude modulated fluorometry (PAM) and oxygen measurements were used to measure photosynthetic activity during the first few hours after rehydration under various light intensities and salinities. Upon rehydration, a transitory maximum in respiratory activity (10-30 min) occurred before the resumption of photosynthesis, which could recover in about 2 h. Salinities outside the mats' natural range (35-50 psu) were detrimental to photosynthetic recovery. Both high (100 psu) and low (0-10 psu) salinities slowed recovery as well as lowered the overall photosynthetic yield. Photosynthesis was initiated earlier and recovered more rapidly with increasing light intensity. In addition, the positive effect of light on rates of recovery was disproportionately greater at lower salinities (10-25 psu) where high light (500 W(.)m(-2)) counteracted the negative effects of low-salt stress early in recovery. However, higher light intensities became photoinhibitory later in recovery (> 2 h). Photosynthesis did not recover uniformly within the mat. Filaments deeper in the mat most likely recovered later than those near the surface due to high light attenuation. The ability of the mats to tolerate desiccation and take advantage of hydration periods even when conditions are suboptimal enables these mats to predominate in the intertidal environment. C1 Univ Oregon, Ctr Ecol & Evolut, Eugene, OR 97403 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ Oregon, Ctr Ecol & Evolut, Eugene, OR 97403 USA. RP Fleming, ED (reprint author), Univ Oregon, Ctr Ecol & Evolut, Eugene, OR 97403 USA. EM efleming@uoregon.edu NR 51 TC 16 Z9 16 U1 3 U2 13 PU BLACKWELL PUBLISHING PI OXFORD PA 9600 GARSINGTON RD, OXFORD OX4 2DQ, OXON, ENGLAND SN 0022-3646 J9 J PHYCOL JI J. Phycol. PD FEB PY 2007 VL 43 IS 1 BP 15 EP 24 DI 10.1111/j.1529-8817.2006.00297.x PG 10 WC Plant Sciences; Marine & Freshwater Biology SC Plant Sciences; Marine & Freshwater Biology GA 133HP UT WOS:000244004300002 ER PT J AU Marotzke, J Fu, LL Tziperman, E AF Marotzke, Jochem Fu, Lee-Lueng Tziperman, Eli TI Carl Wunsch Special Issue - Preface SO JOURNAL OF PHYSICAL OCEANOGRAPHY LA English DT Editorial Material C1 Max Planck Inst Meteorol, D-20146 Hamburg, Germany. Jet Propuls Lab, Pasadena, CA USA. Harvard Univ, Dept Earth & Planetary Sci, Cambridge, MA 02138 USA. Harvard Univ, Div Engn & Appl Sci, Cambridge, MA 02138 USA. RP Marotzke, J (reprint author), Max Planck Inst Meteorol, Bundesstr 55, D-20146 Hamburg, Germany. NR 0 TC 0 Z9 0 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-3670 J9 J PHYS OCEANOGR JI J. Phys. Oceanogr. PD FEB PY 2007 VL 37 IS 2 BP 133 EP 134 DI 10.1175/JPO9030.1 PG 2 WC Oceanography SC Oceanography GA 141DP UT WOS:000244558000001 ER PT J AU Munk, W Bills, B AF Munk, Walter Bills, Bruce TI Tides and the climate: Some speculations SO JOURNAL OF PHYSICAL OCEANOGRAPHY LA English DT Article ID INTERNAL TIDES; ABYSSAL OCEAN; DISSIPATION; GENERATION; MODEL; SEAS AB The important role of tides in the mixing of the pelagic oceans has been established by recent experiments and analyses. The tide potential is modulated by long-period orbital modulations. Previously, Loder and Garrett found evidence for the 18.6-yr lunar nodal cycle in the sea surface temperatures of shallow seas. In this paper, the possible role of the 41 000-yr variation of the obliquity of the ecliptic is considered. The obliquity modulation of tidal mixing by a few percent and the associated modulation in the meridional overturning circulation ( MOC) may play a role comparable to the obliquity modulation of the incoming solar radiation ( insolation), a cornerstone of the Milankovic theory of ice ages. This speculation involves even more than the usual number of uncertainties found in climate speculations. C1 Scripps Inst Oceanog, La Jolla, CA 92093 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Munk, W (reprint author), Scripps Inst Oceanog, 9500 Gilman Dr,Mail Code 0225, La Jolla, CA 92093 USA. EM wmunk@ucsd.edu RI Bills, Bruce/C-1156-2008 NR 33 TC 13 Z9 14 U1 0 U2 11 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-3670 EI 1520-0485 J9 J PHYS OCEANOGR JI J. Phys. Oceanogr. PD FEB PY 2007 VL 37 IS 2 BP 135 EP 147 DI 10.1175/JPO3002.1 PG 13 WC Oceanography SC Oceanography GA 141DP UT WOS:000244558000002 ER PT J AU Fu, LL AF Fu, Lee-Lueng TI Intraseasonal variability of the equatorial Indian Ocean observed from sea surface height, wind, and temperature data SO JOURNAL OF PHYSICAL OCEANOGRAPHY LA English DT Article ID DYNAMICS; OSCILLATION; MONSOON; MODEL; PROPAGATION; CIRCULATION; BOUNDARY; PERIOD; 26-DAY; WAVES AB The forcing of the equatorial Indian Ocean by the highly periodic monsoon wind cycle creates many interesting intraseasonal variabilities. The frequency spectrum of the wind stress observations from the European Remote Sensing Satellite scatterometers reveals peaks at the seasonal cycle and its higher harmonics at 180, 120, 90, and 75 days. The observations of sea surface height ( SSH) from the Jason and Ocean Topography Experiment ( TOPEX)/Poseidon radar altimeters are analyzed to study the ocean's response. The focus of the study is on the intraseasonal periods shorter than the annual period. The semiannual SSH variability is characterized by a basin mode involving Rossby waves and Kelvin waves traveling back and forth in the equatorial Indian Ocean between 10 degrees S and 10 degrees N. However, the interference of these waves with each other masks the appearance of individual Kelvin and Rossby waves, leading to a nodal point ( amphidrome) of phase propagation on the equator at the center of the basin. The characteristics of the mode correspond to a resonance of the basin according to theoretical models. For the semiannual period and the size of the basin, the resonance involves the second baroclinic vertical mode of the ocean. The theory also calls for similar modes at 90 and 60 days. These modes are found only in the eastern part of the basin, where the wind forcing at these periods is primarily located. The western parts of the theoretical modal patterns are not observed, probably because of the lack of wind forcing. There is also similar SSH variability at 120 and 75 days. The 120-day variability, with spatial patterns resembling the semiannual mode, is close to a resonance involving the first baroclinic vertical mode. The 75-day variability, although not a resonant basin mode in theory, exhibits properties similar to the 60- and 90-day variabilities with energy confined to the eastern basin, where the SSH variability seems in resonance with the local wind forcing. The time it takes an oceanic signal to travel eastward as Kelvin waves from the forcing location along the equator and back as Rossby waves off the equator roughly corresponds to the period of the wind forcing. The SSH variability at 60 - 90 days is coherent with sea surface temperature ( SST) with a near-zero phase difference, showing the effects of the time-varying thermocline depth on SST, which may affect the wind in an ocean - atmosphere coupled process governing the intraseasonal variability. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Fu, LL (reprint author), CALTECH, Jet Prop Lab, 300-323,4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM llf@pacific.jpl.nasa.gov NR 32 TC 32 Z9 33 U1 1 U2 6 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-3670 J9 J PHYS OCEANOGR JI J. Phys. Oceanogr. PD FEB PY 2007 VL 37 IS 2 BP 188 EP 202 DI 10.1175/JPO3006.1 PG 15 WC Oceanography SC Oceanography GA 141DP UT WOS:000244558000006 ER EF