FN Thomson Reuters Web of Science™ VR 1.0 PT J AU Reichardt, J Baumgart, R McGee, TJ AF Reichardt, J Baumgart, R McGee, TJ TI Three-signal method for accurate measurements of depolarization ratio with lidar SO APPLIED OPTICS LA English DT Article ID AEROSOL; CIRRUS AB A method is presented that permits the determination of atmospheric depolarization-ratio profiles from three elastic-backscatter lidar signals with different sensitivity to the state of polarization of the backscattered light. The three-signal method is far less sensitive to experimental errors and does not require calibration of the measurement, as is the case of the two-signal lidar technique conventionally used for the observation of depolarization ratios. The three-signal method is applied to a polar stratospheric cloud observation. In the analysis we show that, depending on the statistical error of the measurement and on the lidar system parameters, the new method requires minimum cloud volume depolarization ratios to be applicable; in the case study presented, this threshold is similar to0.2. Depolarization ratios determined with the three-signal method can be used to accurately calibrate measurements with the conventional two-signal technique. (C) 2003 Optical Society of America. C1 NASA, Goddard Space Flight Ctr, Atmospher Chem & Dynam Branch, Atmospheres Lab, Greenbelt, MD 20771 USA. Univ Maryland Baltimore Cty, Joint Ctr Earth Syst Technol, Baltimore, MD 21250 USA. GKSS Forschungszentrum Geesthacht GmbH, D-21502 Geesthacht, Germany. RP NASA, Goddard Space Flight Ctr, Atmospher Chem & Dynam Branch, Atmospheres Lab, Greenbelt, MD 20771 USA. EM reichardt@code916.gsfc.nasa.gov; rudolf.baumgart@gkss.de; mcgee@aeolus.gsfe.nasa.gov RI McGee, Thomas/G-4951-2013 NR 11 TC 16 Z9 16 U1 0 U2 2 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 AUG 20 PY 2003 VL 42 IS 24 BP 4909 EP 4913 DI 10.1364/AO.42.004909 PG 5 WC Optics SC Optics GA 714XR UT WOS:000184940000017 PM 12952338 ER PT J AU Mishchenko, MI AF Mishchenko, MI TI Microphysical approach to polarized radiative transfer: extension to the case of an external observation point SO APPLIED OPTICS LA English DT Article AB The self-consistent microphysical approach applied recently to the transfer of polarized radiation inside a volume of anisotropic discrete random medium is extended to the case of an external observation point. Specifically, it is demonstrated that the solution of the vector radiative transfer equation yields all quantities necessary to calculate the response of an external collimated detector of polarized radiation as a function of the detector orientation and position relative to the scattering volume. C1 NASA, Goddard Inst Space Studies, New York, NY 10025 USA. RP NASA, Goddard Inst Space Studies, 2880 Broadway, New York, NY 10025 USA. EM crmim@giss.nasa.gov RI Mishchenko, Michael/D-4426-2012 NR 2 TC 21 Z9 22 U1 1 U2 2 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 AUG 20 PY 2003 VL 42 IS 24 BP 4963 EP 4967 DI 10.1364/AO.42.004963 PG 5 WC Optics SC Optics GA 714XR UT WOS:000184940000023 PM 12952344 ER PT J AU Jimenez, R Verde, L Treu, T Stern, D AF Jimenez, R Verde, L Treu, T Stern, D TI Constraints on the equation of state of dark energy and the Hubble constant from stellar ages and the cosmic microwave background SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmological parameters; cosmology : theory; distance scale; galaxies : evolution ID EARLY-TYPE GALAXIES; FIELD ELLIPTIC GALAXIES; WHITE-DWARF DISTANCE; GLOBULAR-CLUSTERS; REDSHIFT SURVEY; ACCELERATING UNIVERSE; COSMOLOGICAL CONSTANT; INTERMEDIATE REDSHIFT; LUMINOSITY FUNCTION; SPACE-TELESCOPE AB We place constraints on the redshift-averaged, effective value of the equation of state of dark energy, w, using only the absolute ages of Galactic stars and the observed position of the first peak in the angular power spectrum of the cosmic microwave background (CMB). We find w < -0.8 at the 68% confidence level. If we further consider that w &GE; -1, this finding suggests that within our uncertainties, dark energy is indistinguishable from a classical vacuum energy term. We detect a correlation between the ages of the oldest galaxies and their redshift. This opens up the possibility of measuring w(z) by computing the relative ages of the oldest galaxies in the universe as a function of redshift, dz/dt. We show that this is a realistic possibility by computing dz/dt at z &SIM; 0 from Sloan Digital Sky Survey (SDSS) galaxies and obtain an independent estimate for the Hubble constant, H-0 = 69 +/- 12 km s(-1) Mpc(-1). The small number of galaxies considered at z > 0.2 does not yield, currently, a precise determination of w(z), but shows that the age-redshift relation is consistent with a standard LambdaCDM universe with w = -1. C1 Univ Penn, Dept Phys & Astron, Philadelphia, PA 19104 USA. Princeton Univ, Dept Astrophys Sci, Princeton, NJ 08544 USA. CALTECH, Pasadena, CA 91125 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Jimenez, R (reprint author), Univ Penn, Dept Phys & Astron, Philadelphia, PA 19104 USA. OI Verde, Licia/0000-0003-2601-8770; Jimenez, Raul/0000-0002-3370-3103 NR 61 TC 189 Z9 194 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 AUG 20 PY 2003 VL 593 IS 2 BP 622 EP 629 DI 10.1086/376595 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 712XA UT WOS:000184823400004 ER PT J AU Michael, E McCray, R Chevalier, R Filippenko, AV Lundqvist, P Challis, P Sugerman, B Lawrence, S Pun, CSJ Garnavich, P Kirshner, R Crotts, A Fransson, C Li, WD Panagia, N Phillips, M Schmidt, B Sonneborn, G Suntzeff, N Wang, LF Wheeler, JC AF Michael, E McCray, R Chevalier, R Filippenko, AV Lundqvist, P Challis, P Sugerman, B Lawrence, S Pun, CSJ Garnavich, P Kirshner, R Crotts, A Fransson, C Li, WD Panagia, N Phillips, M Schmidt, B Sonneborn, G Suntzeff, N Wang, LF Wheeler, JC TI Hubble Space Telescope observations of high-velocity Ly alpha and H alpha emission from supernova remnant 1987A: The structure and development of the reverse shock SO ASTROPHYSICAL JOURNAL LA English DT Article DE shock waves; supernovae : individual (SN 1987A); supernova remnants ID LARGE-MAGELLANIC-CLOUD; X-RAY REMNANT; SN 1987A; CIRCUMSTELLAR RING; INTERSTELLAR EXTINCTION; LINE EMISSION; HOT-SPOTS; SN-1987A; EVOLUTION; EJECTA AB We present two-dimensional line profiles of high-velocity (similar to+/-12,000 km s(-1)) Lyalpha and Halpha emission from supernova remnant 1987A obtained with the Space Telescope Imaging Spectrograph between 1997 September and 2001 September (days 3869-5327 after the explosion). This emission comes from hydrogen in the debris that is excited and ionized as it passes through the remnant's reverse shock. We use these profiles to measure the geometry and development of the reverse-shock surface. The observed emission is confined within similar to+/-30degrees about the remnant's equatorial plane. At the equator, the reverse shock has a radius of similar to75% of the distance to the equatorial ring. We detect marginal differences (6% +/- 3%) between the location of the reverse-shock front in the northeast and southwest parts of the remnant. The radius of the reverse shock surface increases for latitudes above the equator, a geometry consistent with a model in which the supernova debris expands into a bipolar nebula. Assuming that the outer supernova debris has a power-law density distribution, we can infer from the reverse-shock emission light curve an expansion rate ( in the northeast part of the remnant) of 3700 +/- 900 km s(-1), consistent with the expansion velocities determined from observations in radio ( Manchester et al.) and X-ray ( Park et al.; Michael et al.) wavelengths. However, our most recent observation ( at day 5327) suggests that the rate of increase of mass flux across the northeast sector of the reverse shock has accelerated, perhaps because of deceleration of the reverse shock caused by the arrival of a reflected shock created when the blast wave struck the inner ring. Resonant scattering within the supernova debris causes Lyalpha photons created at the reverse shock to be directed preferentially outward, resulting in a factor of similar to5 difference in the observed brightness of the reverse shock in Lyalpha between the near and far sides of the remnant. Accounting for this effect, we compare the observed reverse-shock Lyalpha and Halpha fluxes to infer the amount of interstellar extinction by dust as E(B - V) = 0.17 +/- 0.01 mag. We also notice extinction by dust in the equatorial ring with E(B - V) approximate to 0.02-0.08 mag, which implies dust-to-gas ratios similar to that of the LMC. Since Halpha photons are optically thin to scattering, the observed asymmetry in brightness of Halpha from the near and far sides of the remnant represents a real asymmetry in the mass flux through the reverse shock of similar to30%. We discuss future observational strategies that will permit us to further investigate the reverse-shock dynamics and resonant scattering of the Lyalpha line and to constrain better the extinction by dust within and in front of the remnant. C1 Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. Univ Virginia, Dept Astron, Charlottesville, VA 22903 USA. Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA. Dept Astron, Stockholm Observ, SCFAB, SE-10691 Stockholm, Sweden. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Hofstra Univ 151, Dept Phys & Astron, Hempstead, NY 11590 USA. NASA, Lab Astron & Space Phys, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Notre Dame, Dept Phys, Notre Dame, IN 46556 USA. STScI, Baltimore, MD 21218 USA. Carnegie Inst Washington, Las Campanas Observ, La Serena, Chile. Australian Natl Univ, Mt Stromlo & Siding Spring Observ, Weston, ACT 2611, Australia. Cerro Tololo Interamer Observ, La Serena, Chile. Univ Calif Berkeley, Lawrence Berkeley Lab, Inst Nucl & Particle Astrophys, Berkeley, CA 94720 USA. Univ Texas, Dept Astron, Austin, TX 78712 USA. RP Michael, E (reprint author), Univ Colorado, Joint Inst Lab Astrophys, Campus Box 440, Boulder, CO 80309 USA. NR 39 TC 39 Z9 40 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 AUG 20 PY 2003 VL 593 IS 2 BP 809 EP 830 DI 10.1086/376725 PN 1 PG 22 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 712XA UT WOS:000184823400017 ER PT J AU Kuan, YJ Charnley, SB Huang, HC Tseng, WL Kisiel, Z AF Kuan, YJ Charnley, SB Huang, HC Tseng, WL Kisiel, Z TI Interstellar glycine SO ASTROPHYSICAL JOURNAL LA English DT Article DE astrobiology; ISM : abundances; ISM : individual (Orion Kleinmann-Low, Sagittarius B2(N-LMH), W51 e1/e2); ISM : molecules; line : identification; radio lines : ISM ID MOLECULAR LINE SURVEY; MILLIMETER-WAVE SPECTRUM; ORION KLEINMANN-LOW; AMINO-ACIDS; SAGITTARIUS B2; CARBONACEOUS CHONDRITES; APERTURE SYNTHESIS; ORGANIC-MOLECULES; FORMIC-ACID; PARENT BODY AB We have searched for interstellar conformer I glycine (NH(2)CH(2)COOH), the simplest amino acid, in the hot molecular cores Sgr B2(N-LMH), Orion KL, and W51 e1/e2. An improved search strategy for intrinsically weak molecular lines, involving multisource observations, has been developed and implemented. In total, 82 spectral frequency bands, in the millimeter-wave region, were observed over a 4 yr period; 27 glycine lines were detected in 19 different spectral bands in one or more sources. The rotational temperatures derived from "rotation diagrams" are 75(-16)(+29) K for Sgr B2(N-LMH), 141(-37)(+76) K for Orion KL, and 121(-32)(+71) K for W51 e1/e2. The total column densities inferred are 4.16(-1.8)(+3.22) x 10(14) cm(-2) for Sgr B2, 4.37(-1.27)(+1.79) x 10(14) cm(-2) for Orion, and 2.09(-0.77)(+1.22) x 10(14) cm(-2) for W51. Production of interstellar glycine by both gas-phase ion-molecule reactions and by ultraviolet photolysis of molecular ices is briefly discussed. The discovery of interstellar glycine strengthens the thesis that interstellar organic molecules could have played a pivotal role in the prebiotic chemistry of the early Earth. C1 Natl Taiwan Normal Univ, Dept Earth Sci, Taipei 116, Taiwan. Acad Sinica, Inst Astron & Astrophys, Taipei 106, Taiwan. NASA, Div Space Sci, Ames Res Ctr, Moffett Field, CA 94035 USA. Polish Acad Sci, Inst Phys, PL-02668 Warsaw, Poland. RP Kuan, YJ (reprint author), Natl Taiwan Normal Univ, Dept Earth Sci, 88 Sec 4,Ting Chou Rd, Taipei 116, Taiwan. RI Charnley, Steven/C-9538-2012; Kisiel, Zbigniew/K-8798-2016 OI Kisiel, Zbigniew/0000-0002-2570-3154 NR 66 TC 235 Z9 238 U1 0 U2 41 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 AUG 20 PY 2003 VL 593 IS 2 BP 848 EP 867 DI 10.1086/375637 PN 1 PG 20 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 712XA UT WOS:000184823400019 ER PT J AU Kallman, TR Meszaros, P Rees, MJ AF Kallman, TR Meszaros, P Rees, MJ TI Iron K lines from gamma-ray bursts SO ASTROPHYSICAL JOURNAL LA English DT Article DE gamma rays : bursts ID ALPHA EMISSION; AFTERGLOW; ABSORPTION; REFLECTION; ENVIRONMENTS; PROGENITORS; PREDICTIONS; GRB-970828; EJECTA; MODELS AB We present models for reprocessing of an intense flux of X-rays and gamma rays expected in the vicinity of gamma-ray burst sources. We consider the transfer and reprocessing of the energetic photons into observable features in the X-ray band, notably the K lines of iron. Our models are based on the assumption that the gas is sufficiently dense to allow the microphysical processes to be in a steady state, thus allowing efficient line emission with modest reprocessing mass and elemental abundances ranging from solar to moderately enriched. We show that the reprocessing is enhanced by down-Comptonization of photons whose energy would otherwise be too high to absorb in iron and that pair production can have an effect on enhancing the line production. Both "distant" reprocessors, such as supernova or wind remnants, and "nearby" reprocessors, such as outer stellar envelopes, can reproduce the observed line fluxes with Fe abundances 30-100 times above solar, depending on the incidence angle. The high incidence angles required arise naturally only in nearby models, which for plausible values can reach Fe line-to-continuum ratios close to the reported values. C1 NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. Penn State Univ, Dept Astron & Astrophys, University Pk, PA 16803 USA. Univ Cambridge, Inst Astron, Cambridge CB3 0HA, England. RP Kallman, TR (reprint author), NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Code 665, Greenbelt, MD 20771 USA. NR 37 TC 11 Z9 11 U1 0 U2 1 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 AUG 20 PY 2003 VL 593 IS 2 BP 946 EP 960 DI 10.1086/376676 PN 1 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 712XA UT WOS:000184823400026 ER PT J AU Narita, T Grindlay, JE Bloser, PF Chou, Y AF Narita, T Grindlay, JE Bloser, PF Chou, Y TI X-ray dip monitoring of XB 1916-053 SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; binaries : close; X-rays : binaries ID ADVECTION-DOMINATED ACCRETION; ACTIVE GALACTIC NUCLEI; 4U 1915-05; BEPPOSAX OBSERVATION; SPECTRAL VARIATIONS; DISK CORONAE; BLACK-HOLES; CYGNUS X-1; BINARIES; ABSORPTION AB We report on the long-term monitoring of X-ray dips from the ultracompact low-mass X-ray binary (LMXB) XB 1916-053. Roughly one-month interval observations were carried out with the Rossi X-ray Timing Explorer (RXTE) during 1996, during which the source varied between dim, hard states and more luminous, soft states. The dip spectra and dip light curves were compared against both the broadband luminosity and the derived mass accretion rate ((M)over dot). The dips spectra could be fitted by an absorbed blackbody plus cutoff power-law nondip spectral model, with additional absorption ranging from 0 to > 100 x 10(22) cm(-2). The amount of additional blackbody absorption was found to vary with the source luminosity. Our results are consistent with an obscuration of the inner disk region by a partially ionized outer disk. The size of the corona, derived from the dip ingress times, was found to be similar to10(9) cm. The corona size did not correlate with the coronal temperature, but seemed to increase when (M)over dot also increased. We discuss our. ndings in the context of an evaporated accretion disk corona model and an ADAF-type model. C1 Coll Holy Cross, Dept Phys, Worcester, MA 01610 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Natl Cent Univ, Grad Inst Astron, Taoyuan, Taiwan. RP Narita, T (reprint author), Coll Holy Cross, Dept Phys, Worcester, MA 01610 USA. RI Chou, Yi/C-4922-2008 OI Chou, Yi/0000-0002-8584-2092 NR 47 TC 6 Z9 6 U1 0 U2 1 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 AUG 20 PY 2003 VL 593 IS 2 BP 1007 EP 1012 DI 10.1086/376693 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 712XA UT WOS:000184823400031 ER PT J AU Bemporad, A Poletto, G Suess, ST Ko, YK Parenti, S Riley, P Romoli, M Zurbuchen, TZ AF Bemporad, A Poletto, G Suess, ST Ko, YK Parenti, S Riley, P Romoli, M Zurbuchen, TZ TI Temporal evolution of a streamer complex: Coronal and in situ plasma parameters SO ASTROPHYSICAL JOURNAL LA English DT Article DE solar wind; Sun : abundances; Sun : corona; Sun : UV radiation ID UPPER SOLAR ATMOSPHERE; WHOLE SUN MONTH; ELEMENTAL ABUNDANCES; QUIET-SUN; WIND; SPECTROMETER; SOHO; MINIMUM; TEMPERATURES; DENSITIES AB We report on observations acquired by the Ultraviolet Coronagraph Spectrometer (UVCS) aboard the Solar and Heliospheric Observatory (SOHO), from 2000 June 10 to June 17 at the time of a SOHO-Sun-Ulysses quadrature. UVCS took data at 1.6 and 1.9 R-circle dot with a slit normal to the solar radius and centered along the radial to Ulysses. A streamer complex was sampled by UVCS throughout the quadrature campaign, giving us the opportunity to derive plasma parameters in different streamers and to compare them with plasma properties measured in situ. Large Angle Spectroscopic Coronagraph images above 2 R-circle dot helped us understand the temporal evolution of the streamer complex. We derive densities, temperatures, and elemental abundances in two streamers, which have different temperatures and element abundances. In spite of these differences, both structures have the same first ionization potential (FIP) bias. The Fe/O ratio, which may be considered a proxy for the FIP effect, was measured in situ by the Solar Wind Ion Composition Spectrometer aboard the Ulysses spacecraft. Values of Fe/O measured in the corona at the sites where in situ plasma originated agree with in situ Fe/O values. C1 Univ Florence, Dipartimento Astron & Sci Spazio, I-50125 Florence, Italy. Osserv Astrofis Arcetri, I-50125 Florence, Italy. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Sci Applicat Int Corp, San Diego, CA 92121 USA. Univ Michigan, Dept Atmospher Ocean & Space Sci, Ann Arbor, MI 48109 USA. RP Univ Florence, Dipartimento Astron & Sci Spazio, Largo Fermi 5, I-50125 Florence, Italy. EM bemporad76@arcetri.astro.it; poletto@arcetri.astro.it; steve.suess@nsstc.nasa.gov; yko@cfa.harvard.edu; susanna.parenti@medoc-ias.u-psud.fr; pete.riley@saic.co; romoli@arcetri.astro.it; thomasz@umich.edu RI Romoli, Marco/H-6859-2012; OI Bemporad, Alessandro/0000-0001-5796-5653 NR 51 TC 24 Z9 24 U1 0 U2 1 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 AUG 20 PY 2003 VL 593 IS 2 BP 1146 EP 1163 DI 10.1086/376605 PN 1 PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 712XA UT WOS:000184823400043 ER PT J AU Peeters, Z Botta, O Charnley, SB Ruiterkamp, R Ehrenfreund, P AF Peeters, Z Botta, O Charnley, SB Ruiterkamp, R Ehrenfreund, P TI The astrobiology of nucleobases SO ASTROPHYSICAL JOURNAL LA English DT Article DE circumstellar matter; meteors, meteoroids; methods : laboratory ID POLYCYCLIC AROMATIC-HYDROCARBONS; INFRARED SPECTROSCOPIC EVIDENCE; INTERSTELLAR CLOUDS; MOLECULAR CLOUDS; RADIATION-FIELD; SOLID ARGON; AMINO-ACIDS; METEORITES; SPECTRA; IRRADIATION AB Nucleobases are nitrogen heterocycles (N-heterocycles) that are essential components of the genetic material in all living organisms. Extraterrestrial nucleobases have been found in several carbonaceous chondrites, but only in traces. No astronomical data on these complex molecules are currently available. A large fraction of the cosmic carbon is known to be incorporated into aromatic material, and given the relatively high abundance of cosmic nitrogen, the presence of N-heterocycles can be expected. We present infrared spectroscopic laboratory data of adenine and uracil under simulated space conditions. At the same time we tested the stability of these nucleobases against ultraviolet (UV) irradiation at 12 K. Our experimental results indicate that gas-phase adenine and uracil will be destroyed within hours in the Earth's vicinity. In dense interstellar clouds exposed to UV radiation, only adenine could be expected to survive for a few million years. We discuss possible formation routes to purines and pyrimidines in circumstellar environments and in meteorite parent bodies. C1 Leiden Univ, Leiden Inst Chem, Astrobiol Lab, NL-2300 RA Leiden, Netherlands. NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA. Leiden Observ, NL-2300 RA Leiden, Netherlands. RP Peeters, Z (reprint author), Leiden Univ, Leiden Inst Chem, Astrobiol Lab, NL-2300 RA Leiden, Netherlands. RI Charnley, Steven/C-9538-2012 NR 31 TC 43 Z9 43 U1 2 U2 15 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 AUG 20 PY 2003 VL 593 IS 2 BP L129 EP L132 DI 10.1086/378346 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 712XD UT WOS:000184823900018 ER PT J AU Reeves, JN O'Brien, PT Ward, MJ AF Reeves, JN O'Brien, PT Ward, MJ TI A massive X-ray outflow from the quasar PDS 456 SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : active; quasars : individual (PDS 456); X-rays : galaxies ID BROAD ABSORPTION-LINE; ACTIVE GALACTIC NUCLEI; XMM-NEWTON; LUMINOUS QUASAR; EMISSION-LINE; DISK WINDS; BLACK-HOLE; DISCOVERY; ACCRETION; APM-08279+5255 AB We report on XMM-Newton spectroscopic observations of the luminous radio-quiet quasar PDS 456. The hard X-ray spectrum of PDS 456 shows a deep absorption trough (constituting 50% of the continuum) at energies above 7 keV in the quasar rest frame, which can be attributed to a series of blueshifted K-shell absorption edges due to highly ionized iron. The higher resolution soft X-ray Reflection Grating Spectrometer spectrum exhibits a broad absorption line feature near 1 keV, which can be modeled by a blend of L-shell transitions from highly ionized iron (Fe XVII-Fe XXIV). An extreme outflow velocity of similar to50,000 km s(-1) is required to model the K- and L-shell iron absorption present in the XMM-Newton data. Overall, a large column density (N-H = 5 x 10(23) cm(-2)) of highly ionized gas (log xi = 2.5) is required in PDS 456. A high-mass outflow rate of similar to10 M. yr(-1) (assuming a conservative outflow covering factor of 0.1 sr) is derived, which is of the same order as the overall mass accretion rate in PDS 456. The kinetic energy of the outflow represents a substantial fraction (similar to10%) of the quasar energy budget, while the large column and outflow velocity place PDS 456 toward the extreme end of the broad absorption line quasar population. C1 NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. Univ Leicester, Xray & Observat Astron Grp, Leicester LE1 7RH, Leics, England. Univ Space Res Assoc, Columbia, MD USA. RP Reeves, JN (reprint author), NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Code 662,Greenbelt Rd, Greenbelt, MD 20771 USA. NR 27 TC 109 Z9 109 U1 0 U2 1 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 AUG 20 PY 2003 VL 593 IS 2 BP L65 EP L68 DI 10.1086/378218 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 712XD UT WOS:000184823900002 ER PT J AU Vastel, C Phillips, TG Ceccarelli, C Pearson, J AF Vastel, C Phillips, TG Ceccarelli, C Pearson, J TI First detection of doubly deuterated hydrogen sulfide SO ASTROPHYSICAL JOURNAL LA English DT Article DE ISM : abundances; ISM : clouds; ISM : molecules; molecular data; molecular processes; radio lines : ISM ID GRAIN SURFACE-CHEMISTRY; DEUTERIUM FRACTIONATION; DARK CLOUDS; IRAS 16293-2422; CO DEPLETION; MOLECULES; D2CO; IRAS-16293-2422; AMMONIA; SULFUR AB This work was carried out using the Caltech Submillimeter Observatory and presents the observational study of HDS and D2S toward a sample of Class 0 sources and dense cores. We report the first detection of doubly deuterated hydrogen sulfide (D2S) in two dense cores and analyze the chemistry of these molecules, aiming to help understand the deuteration processes in the interstellar medium. The observed values of the D2S/HDS ratio and upper limits require an atomic D/H ratio in the accreting gas of 0.1-1. The study presented in this Letter supports the hypothesis that formaldehyde, methanol, and hydrogen sulfide are formed on the grain surfaces, during the cold prestellar core phase, where the CO-depleted gas has large atomic D/H ratios. The high values for the D/H ratios are consistent with the predictions of a recent gas-phase chemical model that includes H-3(+) and its deuterated isotopomers, H2D+, D2H+, and D-3(+) (Roberts, Herbst, Millar). C1 CALTECH, Downs Lab Phys, Pasadena, CA 91125 USA. Observ Grenoble, Astrophys Lab, F-38041 Grenoble, France. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Vastel, C (reprint author), CALTECH, Downs Lab Phys, MS 320-47,1200 E Calif Blvd, Pasadena, CA 91125 USA. NR 37 TC 58 Z9 59 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 AUG 20 PY 2003 VL 593 IS 2 BP L97 EP L100 DI 10.1086/378261 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 712XD UT WOS:000184823900010 ER PT J AU Guo, JJ Tsang, L Chang, ATC Li, Q Huang, CC Ding, KH AF Guo, JJ Tsang, L Chang, ATC Li, Q Huang, CC Ding, KH TI Bistatic phase function and fast solution of scattering by 2D random distributed scatterers SO MICROWAVE AND OPTICAL TECHNOLOGY LETTERS LA English DT Article DE sparse-matrix canonical-grid method; Monte Carlo simulation; phase function ID DENSE MEDIA; EQUATIONS AB We present large-scale Monte Carlo simulation results of the phase functions in multiple scattering by dense media of small 2D particles. Solution of the Foldy-Lax equations with large number of unknowns is done efficiently using the sparse-matrix canonical-grid (SMCG) method. The SMCG method facilitates the use of FFT and results in an N log N-type efficiency for CPU and O(N) for memory. This dependence is demonstrated by the simulation of CPU time using up to 50000 particles that are randomly distributed through random walk in a large area of 400 square wavelengths. The bistatic phase functions for a random medium are computed. The phase function converges with the number of particles and the number of realizations. The simulation results indicate that the nonsticky particles, sticky particles, and independent scattering have similar angular distribution patterns of the phase Junctions. However, the dense sticky particles show stronger scattering than the independent scattering, while the dense nonsticky particles have smaller scattering than that of the independent scattering. (C) 2003 Wiley Periodicals, Inc. C1 Univ Washington, Dept Elect Engn, Seattle, WA 98195 USA. City Univ Hong Kong, Dept Elect Engn, Hong Kong, Hong Kong, Peoples R China. NASA, Goddard Space Flight Ctr, Hydrol Sci Branch, Greenbelt, MD 20771 USA. USAF, Res Lab, Sensors Directorate, SNHE, Hanscom AFB, MA 01731 USA. RP Guo, JJ (reprint author), Univ Washington, Dept Elect Engn, Seattle, WA 98195 USA. NR 10 TC 4 Z9 4 U1 0 U2 1 PU JOHN WILEY & SONS INC PI HOBOKEN PA 111 RIVER ST, HOBOKEN, NJ 07030 USA SN 0895-2477 J9 MICROW OPT TECHN LET JI Microw. Opt. Technol. Lett. PD AUG 20 PY 2003 VL 38 IS 4 BP 313 EP 317 DI 10.1002/mop.11047 PG 5 WC Engineering, Electrical & Electronic; Optics SC Engineering; Optics GA 701YY UT WOS:000184197600018 ER PT J AU Berg, AA Famiglietti, JS Walker, JP Houser, PR AF Berg, AA Famiglietti, JS Walker, JP Houser, PR TI Impact of bias correction to reanalysis products on simulations of North American soil moisture and hydrological fluxes SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE land surface modeling; hydroclimatology; soil moisture; reanalysis; hydrometeorological forcing ID LAND-SURFACE PROCESSES; SAHELIAN CLIMATE PREDICTION; GENERAL-CIRCULATION MODELS; CATCHMENT-BASED APPROACH; WATER-HOLDING CAPACITY; 1987 FIFE DATA; ECMWF REANALYSIS; NCEP/NCAR REANALYSIS; DATA ASSIMILATION; BIOSPHERE MODEL AB Simulating land surface hydrological states and fluxes requires a comprehensive set of atmospheric forcing data at consistent temporal and spatial scales. At the continental-to-global scale, such data are not available except in weather reanalysis products. Unfortunately, reanalysis products are often biased due to errors in the host weather forecast model. This paper explores whether the error in model predictions of the initial soil moisture status and hydrological fluxes can be minimized through a bias reduction scheme to the European Centre for Medium Range Weather Forecast and National Center for Environmental Prediction/National Center for Atmospheric Research reanalysis products. The bias reduction scheme uses both difference and ratio corrections based upon global observational data sets. Both the corrected and original forcing data were used to simulate land surface states and fluxes with a land surface model (LSM) over North America. Soil moisture, snow depth, and runoff output from the LSM are compared to observations to assess the impact of the bias correction on simulation accuracy. Results of this study demonstrate the sensitivity of LSMs to bias in the forcing data, and that implementation of a bias reduction scheme reduces errors to the simulation of soil moisture, runoff, and snow water equivalence. Accordingly, the initial soil moisture fields produced should be more representative of actual conditions, and therefore more useful to the climate modeling community. Results suggest that modelers using reanalysis products for forcing LSMs, in particular for the establishment of initial conditions, should consider a bias reduction strategy when preparing their input forcing fields. C1 Univ Calif Irvine, Dept Earth Syst Sci, Irvine, CA 92687 USA. Univ Melbourne, Dept Civil & Environm Engn, Parkville, Vic 3010, Australia. NASA, Goddard Space Flight Ctr, Hydrol Sci Branch, Greenbelt, MD 20771 USA. RP Berg, AA (reprint author), Univ Calif Irvine, Dept Earth Syst Sci, 230 Rowland Hall, Irvine, CA 92687 USA. EM berga@uci.edu; jfamigli@uci.edu; J.walker@unimelb.edu.au; houser@dao.gsfc.nas RI Walker, Jeffrey/D-2624-2009; Houser, Paul/J-9515-2013 OI Houser, Paul/0000-0002-2991-0441 NR 61 TC 72 Z9 76 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 AUG 19 PY 2003 VL 108 IS D16 AR 4490 DI 10.1029/2002JD003334 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 715XE UT WOS:000184998800006 ER PT J AU Lin, JC Gerbig, C Wofsy, SC Andrews, AE Daube, BC Davis, KJ Grainger, CA AF Lin, JC Gerbig, C Wofsy, SC Andrews, AE Daube, BC Davis, KJ Grainger, CA TI A near-field tool for simulating the upstream influence of atmospheric observations: The Stochastic Time-Inverted Lagrangian Transport (STILT) model SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE Lagrangian particle dispersion models; boundary layer transport; land-atmosphere exchange; carbon fluxes; trajectory modeling; global change science ID BOUNDARY-LAYER BUDGETS; AIR-QUALITY MODELS; PARTICLE DISPERSION; INHOMOGENEOUS TURBULENCE; CARBON-DIOXIDE; TALL TOWER; CO2; TRAJECTORIES; FLUXES; FLOWS AB We introduce a tool to determine surface fluxes from atmospheric concentration data in the midst of distributed sources or sinks over land, the Stochastic Time-Inverted Lagrangian Transport (STILT) model, and illustrate the use of the tool with CO2 data over North America. Anthropogenic and biogenic emissions of trace gases at the surface cause large variations of atmospheric concentrations in the planetary boundary layer ( PBL) from the "near field," where upstream sources and sinks have strong influence on observations. Transport in the near field often takes place on scales not resolved by typical grid sizes in transport models. STILT provides the capability to represent near-field influences, transforming this noise to signal useful in diagnosing surface emissions. The model simulates transport by following the time evolution of a particle ensemble, interpolating meteorological fields to the subgrid scale location of each particle. Turbulent motions are represented by a Markov chain process. Significant computational savings are realized because the influence of upstream emissions at different times is modeled using a single particle simulation backward in time, starting at the receptor and sampling only the portion of the domain that influences the observations. We assess in detail the physical and numerical requirements of STILT and other particle models necessary to avoid inconsistencies and to preserve time symmetry (reversibility). We show that source regions derived from backward and forward time simulations in STILT are similar, and we show that deviations may be attributed to violation of mass conservation in currently available analyzed meterological fields. Using concepts from information theory, we show that the particle approach can provide significant gains in information compared to conventional gridcell models, principally during the first hours of transport backward in time, when PBL observations are strongly affected by surface sources and sinks. C1 Harvard Univ, Dept Earth & Planetary Sci, Cambridge, MA 02138 USA. Harvard Univ, Div Engn & Appl Sci, Cambridge, MA 02138 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Penn State Univ, Dept Meteorol, University Pk, PA 16802 USA. Univ N Dakota, Dept Atmospher Sci, Grand Forks, ND 58202 USA. RP Lin, JC (reprint author), Harvard Univ, Dept Earth & Planetary Sci, Pierce Hall,20 Oxford St, Cambridge, MA 02138 USA. EM johnlin@fas.harvard.edu; chg@io.harvard.edu; scw@io.harvard.edu; andrews@code916.gsfc.nasa.gov; bcd@io.harvard.edu; davis@essc.psu.edu; grainger@aero.und.edu RI Andrews, Arlyn/K-3427-2012; Gerbig, Christoph/L-3532-2013 OI Gerbig, Christoph/0000-0002-1112-8603 NR 54 TC 53 Z9 55 U1 3 U2 32 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 AUG 19 PY 2003 VL 108 IS D16 AR 4493 DI 10.1029/2002JD003161 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 715XE UT WOS:000184998800004 ER PT J AU Schmid, B Hegg, DA Wang, J Bates, D Redemann, J Russell, PB Livingston, JM Jonsson, HH Welton, EJ Seinfeld, JH Flagan, RC Covert, DS Dubovik, O Jefferson, A AF Schmid, B Hegg, DA Wang, J Bates, D Redemann, J Russell, PB Livingston, JM Jonsson, HH Welton, EJ Seinfeld, JH Flagan, RC Covert, DS Dubovik, O Jefferson, A TI Column closure studies of lower tropospheric aerosol and water vapor during ACE-Asia using airborne Sun photometer and airborne in situ and ship-based lidar measurements SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE aerosol extinction; water vapor; aircraft measurements of aerosol; Sun photometer; lidar ID MID-ATLANTIC COAST; GROUND-BASED MEASUREMENTS; SINGLE-SCATTERING ALBEDO; OPTICAL-DEPTH SPECTRA; TO-BACKSCATTER RATIO; UNITED-STATES; LIGHT-ABSORPTION; PARTICLE-SIZE; RADIATIVE CLOSURE; SOUTHERN AFRICA AB We assess the consistency (closure) between solar beam attenuation by aerosols and water vapor measured by airborne Sun photometry and derived from airborne in situ and ship-based lidar measurements during the April 2001 Asian Pacific Regional Aerosol Characterization Experiment (ACE-Asia). The airborne data presented here were obtained aboard the Twin Otter aircraft. Comparing aerosol extinction sigma(ep)(550 nm) from four different techniques shows good agreement for the vertical distribution of aerosol layers. However, the level of agreement in absolute magnitude of the derived aerosol extinction varied among the aerosol layers sampled. The sigma(ep)(550 nm) computed from airborne in situ size distribution and composition measurements shows good agreement with airborne Sun photometry in the marine boundary layer but is considerably lower in layers dominated by dust if the particles are assumed to be spherical. The sigma(ep)(550 nm) from airborne in situ scattering and absorption measurements are about similar to13% lower than those obtained from airborne Sun photometry during 14 vertical profiles. Combining lidar and the airborne Sun photometer measurements reveals the prevalence of dust layers at altitudes up to 10 km with layer aerosol optical depth (from 3.5 to 10 km altitude) of similar to0.1 to 0.2 (500 nm) and extinction-to-backscatter ratios of 59-71 sr (523 nm). The airborne Sun photometer aboard the Twin Otter reveals a relatively dry atmosphere during ACE-Asia with all water vapor columns <1.5 cm and water vapor densities rho(w) < 12 g/m(3). Comparing layer water vapor amounts and rw from the airborne Sun photometer to the same quantities measured with aircraft in situ sensors leads to a high correlation (r(2) = 0.96), but the Sun photometer tends to underestimate rho(w) by 7%. C1 Bay Area Environm Res Inst, Sonoma, CA 95476 USA. Univ Washington, Dept Atmospher Sci, Seattle, WA 98195 USA. CALTECH, Dept Chem Engn, Pasadena, CA 91125 USA. Univ Miami, Dept Phys, Coral Gables, FL 33146 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. SRI Int, Menlo Pk, CA 94025 USA. CIRPAS, Moffett Field, CA 93933 USA. NASA, Atmospheres Lab, Goddard Space Flight Ctr, Greenbelt, MD USA. NASA, Goddard Earth Sci & Technol Ctr, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NOAA, Cooperat Inst Res Environm Sci, Climate Monitoring & Diagnost Lab, Boulder, CO 80803 USA. RP Schmid, B (reprint author), Bay Area Environm Res Inst, Sonoma, CA 95476 USA. EM bschmid@mail.arc.nasa.gov; deanhegg@atmos.washington.edu; jian@bnl.gov; bates@physics.miami.edu; jredemann@mail.arc.nasa.gov; philip.b.russell@nasa.gov; jlivingston@mail.arc.nasa.gov; hjonsson@nps.navy.mil; ellsworth.j.welton@nasa.gov; seinfeld@caltech.edu; flagan@cheme.caltech.edu; dcovert@u.washington.edu; dubovik@aeronet.gsfc.nasa.gov; anne.jefferson@noaa.gov RI Dubovik, Oleg/A-8235-2009; Welton, Ellsworth/A-8362-2012; Jefferson, Anne/K-4793-2012; Wang, Jian/G-9344-2011; OI Dubovik, Oleg/0000-0003-3482-6460; Schmitt, Bernard/0000-0002-1230-6627 NR 55 TC 54 Z9 55 U1 0 U2 0 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 AUG 19 PY 2003 VL 108 IS D23 AR 8656 DI 10.1029/2002JD003361 PG 22 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 715XJ UT WOS:000184999300002 ER PT J AU Niebur, SM Scott, LM Wiedenbeck, ME Binns, WR Christian, ER Cummings, AC Davis, AJ George, JS Hink, PL Israel, MH Leske, RA Mewaldt, RA Stone, EC von Rosenvinge, TT Yanasak, NE AF Niebur, SM Scott, LM Wiedenbeck, ME Binns, WR Christian, ER Cummings, AC Davis, AJ George, JS Hink, PL Israel, MH Leske, RA Mewaldt, RA Stone, EC von Rosenvinge, TT Yanasak, NE TI Cosmic ray energy loss in the heliosphere: Direct evidence from electron-capture-decay secondary isotopes SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article DE cosmic ray isotopes; solar modulation; adiabatic energy loss; electron-capture decay ID PARTIAL CROSS-SECTIONS; ADVANCED-COMPOSITION-EXPLORER; SOLAR MODULATION; RELATIVISTIC NUCLEI; PROPAGATION; HYDROGEN; REACCELERATION; TARGETS; MODELS AB [1] Measurements by the Cosmic Ray Isotope Spectrometer (CRIS) on the Advanced Composition Explorer (ACE) spacecraft provide direct evidence that galactic cosmic rays lose energy as a result of their interactions with magnetic fields expanding with the solar wind. The secondary isotopes V-49 and Cr-51 can decay to Ti-49 and V-51, respectively, only by electron capture. The observed abundances of these isotopes are directly related to the probability of attaching an electron from the interstellar medium; this probability decreases strongly with increasing energy around a few hundred MeV/nucleon. At the highest energies observed by CRIS, electron attachment on these nuclides is very unlikely, and thus V-49 and Cr-51 are essentially stable. At lower energies, attachment and decay do occur. Comparison of the energy dependence of the daughter/parent ratios Ti-49/V-49 and V-51/Cr-51 during solar minimum and solar maximum conditions confirms that increased energy loss occurs during solar maximum. This analysis indicates an increase in the modulation parameter phi of about 400 to 700 MV corresponding to an increase in average energy loss for these elements of about 200 to 300 MeV/nucleon. C1 Washington Univ, Dept Phys, St Louis, MO 63130 USA. Washington Univ, McDonnell Ctr Space Sci, St Louis, MO 63130 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. CALTECH, Space Radiat Lab, Pasadena, CA 91125 USA. RP Niebur, SM (reprint author), NASA Headquarters, Code SE, Washington, DC 20546 USA. RI Christian, Eric/D-4974-2012 OI Christian, Eric/0000-0003-2134-3937 NR 27 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 AUG 19 PY 2003 VL 108 IS A10 AR 8033 DI 10.1029/2003JA009876 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 715YB UT WOS:000185001100002 ER PT J AU McNamara, KM AF McNamara, KM TI Aggregate nitrogen in synthetic diamond SO APPLIED PHYSICS LETTERS LA English DT Article ID INFRARED-ABSORPTION AB Nitrogen is a commonly observed impurity in natural and synthetic diamond, yet there are still many questions in regard to its incorporation in the material. In all three common forms of diamond: natural, high-pressure high-temperature synthetic, and chemical vapor deposition (CVD) diamond; nitrogen has been observed in substitutional lattice sites. This configuration results in an unpaired electron which gives rise to an easily observed paramagnetic resonance. In addition, aggregate forms of nitrogen, such as A-center (paired nitrogen), B-center, and platelet-related nitrogen are the predominant form of nitrogen observed in natural Type Ia diamonds. These aggregate forms have yet to be observed unambiguously in any form of synthetic diamond. Here, we show evidence, based on quantitative secondary ion mass spectrometry and electron paramagnetic resonance spectroscopy measurements, of nonparamagnetic nitrogen in some CVD diamond films. Further examination of the symmetry-disallowed one-phonon absorption in the infrared spectra of these films indicates the presence of aggregate nitrogen in these materials. (C) 2003 American Institute of Physics. C1 Worcester Polytech Inst, Worcester, MA 01609 USA. RP McNamara, KM (reprint author), NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. NR 16 TC 7 Z9 8 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 AUG 18 PY 2003 VL 83 IS 7 BP 1325 EP 1327 DI 10.1063/1.1347012 PG 3 WC Physics, Applied SC Physics GA 711NU UT WOS:000184748600015 ER PT J AU Ting, DZY Cartoixa, X AF Ting, DZY Cartoixa, X TI Bidirectional resonant tunneling spin pump SO APPLIED PHYSICS LETTERS LA English DT Article ID HETEROSTRUCTURES AB We propose a mechanism for achieving bidirectional spin pumping in conventional nonmagnetic semiconductor resonant tunneling heterostructures under zero magnetic field. The device is designed specifically to take advantage of the special spin configuration described by the Rashba effect in asymmetric quantum wells. It induces the simultaneous flow of oppositely spin-polarized current components in opposite directions through spin-dependent resonant tunneling, and can thus generate significant levels of spin current with very little net electrical current across the tunnel structure, a condition characterized by a greater-than-unity current spin polarization. We also present modeling results on temperature dependence and finite device size effects. (C) 2003 American Institute of Physics. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. CALTECH, TJ Watson Sr Labs Appl Phys, Pasadena, CA 91109 USA. RP Ting, DZY (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 12 TC 19 Z9 19 U1 1 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 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD AUG 18 PY 2003 VL 83 IS 7 BP 1391 EP 1393 DI 10.1063/1.1602158 PG 3 WC Physics, Applied SC Physics GA 711NU UT WOS:000184748600037 ER PT J AU Cartoixa, X Ting, DZY Chang, YC AF Cartoixa, X Ting, DZY Chang, YC TI A resonant spin lifetime transistor SO APPLIED PHYSICS LETTERS LA English DT Article ID QUANTUM-WELLS; RELAXATION ANISOTROPY AB We present a device concept for a spintronic transistor based on the spin relaxation properties a two-dimensional electron gas (2DEG). The device design is very similar to that of the Datta and Das spin transistor. However, our proposed device works in the diffusive regime rather than in the ballistic regime. This eases lithographical and processing requirements. The switching action is achieved through the biasing of a gate contact, which controls the lifetime of spins injected into the 2DEG from a ferromagnetic emitter, thus allowing the traveling spins to be either aligned with a ferromagnetic collector or randomizing them before collection. The device configuration can easily be turned into a memory and a readout head for magnetically stored information. (C) 2003 American Institute of Physics. C1 Univ Illinois, Dept Phys, Urbana, IL 61801 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Cartoixa, X (reprint author), Univ Illinois, Dept Phys, 1110 W Green St, Urbana, IL 61801 USA. RI Chang, Yia-Chung/F-4239-2011 NR 22 TC 81 Z9 82 U1 1 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 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD AUG 18 PY 2003 VL 83 IS 7 BP 1462 EP 1464 DI 10.1063/1.1601693 PG 3 WC Physics, Applied SC Physics GA 711NU UT WOS:000184748600061 ER PT J AU Bhattacharyya, R Janaki, MS Dasgupta, B AF Bhattacharyya, R Janaki, MS Dasgupta, B TI Relaxation in electron-positron plasma: a possibility SO PHYSICS LETTERS A LA English DT Article ID RELAXED STATES; MODES AB For a non-relativistic electron-positron plasma the possibility of obtaining a relaxed state is explored. The Euler-Lagrange equations are obtained by minimizing the hyper-resistivity with generalized helicities and magnetofluid energy as the constraints. The relaxed state is shown to be morphologically similar to the steady-state equilibria of the electron-positron plasma system. (C) 2003 Elsevier B.V. All rights reserved. C1 Saha Inst Nucl Phys, Kolkata 700064, W Bengal, India. NASA, Jet Prop Lab, CALTECH, Pasadena, CA 91109 USA. RP Bhattacharyya, R (reprint author), Saha Inst Nucl Phys, 1-AF Bidhannagar, Kolkata 700064, W Bengal, India. EM ramit@plasma.saha.ernet.in NR 21 TC 13 Z9 13 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-9601 EI 1873-2429 J9 PHYS LETT A JI Phys. Lett. A PD AUG 18 PY 2003 VL 315 IS 1-2 BP 120 EP 125 DI 10.1016/S0375-9601(03)00977-0 PG 6 WC Physics, Multidisciplinary SC Physics GA 713WE UT WOS:000184880300015 ER PT J AU Kaufman, YJ Haywood, JM Hobbs, PV Hart, W Kleidman, R Schmid, B AF Kaufman, YJ Haywood, JM Hobbs, PV Hart, W Kleidman, R Schmid, B TI Remote sensing of vertical distributions of smoke aerosol off the coast of Africa SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID TROPOSPHERIC AEROSOLS; OPTICAL-PROPERTIES; SAFARI 2000; DRY SEASON; CLIMATE; AIRBORNE; WATER AB In 2004 NASA plans to launch the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations-CALIPSO mission, with a two-wavelength lidar aboard. CALIPSO will fly in formation with the Moderate Resolution Imaging Spectro-Radiometer (MODIS) on the Aqua satellite. Here we present inversions of combined aircraft lidar and MODIS data to study the properties of smoke off the southwest coast of Southern Africa. The inversion derives profiles of the aerosol extinction due to fine and coarse particles. Comparisons with three sets of airborne in situ measurements show excellent agreement of the aerosol extinction profiles; however the inversion derives smaller spectral dependence of the extinction than the in situ measurements. The inversion is sensitive to the aerosol backscattering-to-extinction ratio (BER). Due to nonsphericity of the coarse aerosols, the range of BERs of the smoke aerosol is 0.014 to 0.021 sr(-1) for the fine and coarse particles at 0.53 and 1.06 mum wavelengths, which do not differ much from the value for dust (0.016 sr(-1)) at these wavelengths. C1 NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. Meteorol Off, Bracknell RB12 2SZ, Berks, England. Univ Washington, Dept Atmospher Sci, Seattle, WA 98195 USA. Sci Syst & Applicat Inc, Lanham, MD 20706 USA. Bay Area Environm Res Inst, Sonoma, CA 95476 USA. RP Kaufman, YJ (reprint author), NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. NR 18 TC 22 Z9 23 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 AUG 16 PY 2003 VL 30 IS 16 AR 1831 DI 10.1029/2003GL017068 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 713PT UT WOS:000184867700001 ER PT J AU Kedar, S Hajj, GA Wilson, BD Heflin, MB AF Kedar, S Hajj, GA Wilson, BD Heflin, MB TI The effect of the second order GPS ionospheric correction on receiver positions SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID EARTH SATELLITES AB The Global Positioning System (GPS) transmits two frequencies, allowing users to correct for the first-order ionospheric signal group delay (or phase advance) of 1-50 m. The second-order ionospheric term, caused by the Faraday rotation effect induced by the Earth magnetic field, is about 1000 times smaller and usually ignored. In this study, we implement the 2nd-order correction suggested by Bassiri and Hajj [1993] and investigate its effect on GPS-inferred station positions. The correction causes a latitude dependent similar to0.1-0.5 cm southward shift to the position which is roughly proportional to the integrated electron density above the receiver, and has strong diurnal, seasonal and decadal signatures. By analyzing a three-year time series of equatorial station positions obtained without the 2nd-order correction, a strong semi-annual north-south oscillation is observed, the origin of which has not been hitherto explained. We verify that this apparent oscillation can be largely removed once the 2nd-order correction is applied. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM Sharon.Kedar@jpl.nasa.gov NR 11 TC 100 Z9 110 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 AUG 16 PY 2003 VL 30 IS 16 AR 1829 DI 10.1029/2003GL017639 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 713PT UT WOS:000184867700004 ER PT J AU Mayr, HG Mengel, JG Talaat, ER Porter, HS Chan, KL AF Mayr, HG Mengel, JG Talaat, ER Porter, HS Chan, KL TI Non-migrating diurnal tides generated with planetary waves in the Mesosphere SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID DOPPLER-SPREAD PARAMETERIZATION; LARGE-SCALE DYNAMICS; MIDDLE ATMOSPHERE; GRAVITY-WAVE; LOWER THERMOSPHERE; MOMENTUM DEPOSITION; CIRCULATION MODEL; TIDAL VARIABILITY; SIMULATION; IMPLEMENTATION AB We report results from our Numerical Spectral Model (NSM) that incorporates Hines' parameterization for small-scale gravity waves (GW). The NSM generates non-migrating tides in the mesosphere having amplitudes comparable to those observed, and we demonstrate that they arise from interactions between migrating tides and planetary waves (PW). We examine this mechanism for the large m = 0 diurnal tide, which was proposed to be generated with m = 1 PWs. The NSM is run for comparison without the zonal mean heat source, which suppresses the PWs that normally are excited by instabilities. The resulting amplitudes of the stationary tide are then negligibly small. When the time dependent GW momentum source for m = 0 is turned off, the stationary tide is significantly reduced. This indicates that, in the NSM, GWs play an important role in generating the nonlinear interactions between migrating tides and PWs that are necessary to produce the non-migrating tides. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Sci Syst & Applicat Inc, Lanham, MD USA. Johns Hopkins Univ, Appl Phys Lab, Laurel, MD USA. Furman Univ, Greenville, SC 29613 USA. Hong Kong Univ Sci & Technol, Hong Kong, Hong Kong, Peoples R China. RP Mayr, HG (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 28 TC 19 Z9 19 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 AUG 16 PY 2003 VL 30 IS 16 AR 1832 DI 10.1029/2003GL017877 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 713PT UT WOS:000184867700005 ER PT J AU Schlosser, CA Mocko, DM AF Schlosser, CA Mocko, DM TI Impact of snow conditions in spring dynamical seasonal predictions SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE snow; impact; climate prediction ID GENERAL-CIRCULATION; PART I; COVER; CLIMATE; DESIGN; MODELS; PHASE; TEMPERATURE; SCATTERING; DATASETS AB A suite of numerical simulations with the Center for Ocean Land Atmosphere (COLA) Studies' and the Goddard Earth Observing System (GEOS) general circulation models (GCMs) has been performed in conjunction with the Dynamical Seasonal Prediction (DSP) Project. These simulations aim to quantify the impact of realistic snow conditions on skill in the GCMs. In this study, ensemble climate simulations conducted for Northern Hemisphere spring (March-June) that span the years 1982-1998 are considered. For each year of these seasonal simulations, a pair of complementary runs is performed. For one of the simulations, snow conditions are allowed to evolve interactively; for the other simulation, the snow conditions are prescribed, according to a daily, global snow depth analysis, within each of the land modules of the GCMs. For this study, the impact of snow conditions on simulated near-surface air temperature is assessed. The results indicate that the prescribed (and presumably improved) snow conditions in the GCMs play a beneficial role in skillfully capturing the observed spatial/temporal patterns of interannual variations of near-surface air temperature, at a local scale. Through consideration of the surface energy-budget and the effect of snow cover on surface albedo, the localized improvement of near-surface air temperature skill (both in the spatial correlations and in the root-mean-square error) that results from the prescribed snowfields is found to be strongly tied to when and where the interannual variabilities of snow cover and mean incident short wave radiation coincide. This impact of prescribed snow is also most considerable during the widespread ablation of the matured winter season snow cover, which typically occurs during April over the Northern Hemisphere. Overall, the impact of the prescribed snow over all land points (i.e., local and nonlocal) shows mixed results in its effect on near-surface air temperature skill. These mixed results most likely underscore the difficulty of the GCMs to consistently translate the localized skillful response into nonlocal/remote skill. In the end, physical parameterizations in GCMs should be improved before all seasonal prediction enhancements from improved snow conditions can be realized. C1 NASA, Goddard Space Flight Ctr, Hydrol Sci Branch, Goddard Earth Sci & Technol Ctr, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Climate & Radiat Branch, Atmospheres Lab, Greenbelt, MD 20771 USA. Sci Applicat Int Corp, Gen Sci Operat, Greenbelt, MD USA. RP Schlosser, CA (reprint author), NASA, Goddard Space Flight Ctr, Hydrol Sci Branch, Goddard Earth Sci & Technol Ctr, Code 974, Greenbelt, MD 20771 USA. EM adam@hsb.gsfc.nasa.gov NR 40 TC 11 Z9 11 U1 0 U2 3 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 AUG 16 PY 2003 VL 108 IS D16 AR 8616 DI 10.1029/2002JD003113 PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 713QB UT WOS:000184868500001 ER PT J AU Verigin, M Slavin, J Szabo, A Gombosi, T Kotova, G Plochova, O Szego, K Tatrallyay, M Kabin, K Shugaev, F AF Verigin, M Slavin, J Szabo, A Gombosi, T Kotova, G Plochova, O Szego, K Tatrallyay, M Kabin, K Shugaev, F TI Planetary bow shocks: Gasdynamic analytic approach SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article DE bow shocks; gasdynamic; analytic modeling; bow shock shape; magnetopause shape; boundary conditions ID SOLAR-WIND FLOW; MAGNETOPAUSE SHAPE; TERRESTRIAL PLANETS; FLARING ANGLE; 3-D SHAPE; POSITION; MAGNETOSPHERE; LOCATION; PRESSURE; MODEL AB A new analytical model of the bow shock surface is suggested for reasonably accurate and fast prediction of this boundary's position near obstacles of different shape. For axially symmetric obstacles the model was verified by comparison with experiments and results of gasdynamic code application for a wide range of upstream polytropic indexes, 1.15<γ<2, and Mach numbers, 1 FenC+CO2 reaction SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID COLLISION-INDUCED DISSOCIATION; GAUSSIAN-BASIS SETS; TRANSITION-METAL MONOCARBONYLS; ION PHOTOELECTRON-SPECTROSCOPY; CARBON NANOTUBE PRODUCTION; DENSITY-FUNCTIONAL THEORY; ABLATED IRON ATOMS; CORRELATION-ENERGY; BOND-ENERGIES; HIPCO PROCESS AB The electronic and geometrical structure of the ground and excited states of FenCO, FenCO-, and FenCO+ (n=2-6) are computed using density functional theory (DFT). Several hybrid and pure DFT methods are tested on FeCO and Fe2CO where experimental data are available. The pure DFT methods are superior to hybrid methods in reproduction of experimental spectroscopic data, except for the dissociation energy of FeCO. CO is twofold coordinated in Fe2CO, Fe3CO, and Fe4CO, threefold coordinated in Fe5CO, and fourfold in Fe6CO. While the Boudouard-type disproportionation reaction FenCO+CO-->FenC+CO2 is endothermic by 1.59, 1.10, and 0.55 eV for FeCO, Fe2CO, and Fe3CO, respectively, it becomes exothermic beginning with n=4. The reaction barrier decreases from 3.5 eV for FeCO to 1.3 eV for Fe4CO. The most exothermic (by 0.42 eV) reaction is Fe6CO++CO-->Fe6C++CO2. It is found that the catalytic ability increases with clusters size due to the decreasing FenC-O (or increasing Fe-n-C) bond strength. The Fe-n-CO binding energy varies slowly with cluster size and therefore does not significantly influence the variation in the energetics of the Boudouard-type reaction with cluster size. (C) 2003 American Institute of Physics. C1 NASA, Ames Res Ctr, ELORET Corp, Moffett Field, CA 94035 USA. Univ Virginia, Dept Chem, Charlottesville, VA 22901 USA. RP Gutsev, GL (reprint author), NASA, Ames Res Ctr, ELORET Corp, Mail Stop 230-3, Moffett Field, CA 94035 USA. NR 63 TC 30 Z9 30 U1 0 U2 6 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD AUG 15 PY 2003 VL 119 IS 7 BP 3681 EP 3690 DI 10.1063/1.1590953 PG 10 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 706UU UT WOS:000184474100013 ER PT J AU Smrekar, SE Comstock, R Anderson, FS AF Smrekar, SE Comstock, R Anderson, FS TI A gravity survey of Type 2 coronae on Venus SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article DE corona; admittance; gravity; isostasy; lithosphere; crust ID EFFECTIVE ELASTIC THICKNESS; OF-SIGHT ACCELERATIONS; CONTINENTAL LITHOSPHERE; ISOSTATIC COMPENSATION; ORDER MODEL; TOPOGRAPHY; FLEXURE; CONSTRAINTS; ANOMALIES; EVOLUTION AB Coronae are roughly circular tectonic features believed to form as a result of small-scale mantle upwellings. We examine the admittance signature for all the 32 Type 2 coronae (defined as having less than 50% complete fracture annuli) that are both well resolved in the gravity data and have fairly well constrained lithospheric parameters. We use top and bottom loading models to derive values of elastic thickness and crustal thickness or apparent depth of compensation. Both Cartesian and spatiospectral methods are used to calculate admittance. Overall we find reasonable agreement between the two methods. The shape of the filter used in the spatiospectral method [Simons et al., 1997] provides a means of isolating the signature of coronae that occur in close proximity to other geologic features. The narrow filters used in the Cartesian approach are useful for identifying transitions between different types of compensation, as well as for estimating error. We obtain a wide range of elastic thicknesses, from 25 to 80 km. Larger values are derived from bottom loading models, which have not been used in most prior studies of Venus. Fifteen of the coronae have elastic thickness values between 0 and 20 km and are probably isostatically compensated. Estimates of crustal and elastic thicknesses and apparent depth of compensation obtained for Type 2 coronae span the range obtained for Venus globally. Neither the thickness of the elastic lithosphere nor the crust appear to control whether Type 1 coronae, Type 2 coronae, or volcanoes form over small-scale mantle upwellings. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Calif San Diego, Scripps Inst Oceanog, Inst Geophys & Planetary Phys, La Jolla, CA 92093 USA. Univ Hawaii Manoa, Hawaii Inst Geophys & Planetol, Honolulu, HI 96822 USA. RP Smrekar, SE (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,Mail Stop 183-501, Pasadena, CA 91109 USA. NR 44 TC 13 Z9 13 U1 0 U2 0 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 AUG 15 PY 2003 VL 108 IS E8 AR 5090 DI 10.1029/2002JE001935 PG 17 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 713QN UT WOS:000184869600003 ER PT J AU Smrekar, SE Stofan, ER AF Smrekar, SE Stofan, ER TI Effects of lithospheric properties on the formation of Type 2 coronae on Venus SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article DE corona; isostasy; delamination; lithosphere; flexure; plume ID STAGNANT LID CONVECTION; TOPOGRAPHY; GRAVITY; ORIGIN; MODELS; EVOLUTION; HOTSPOTS; FEATURES; PLUMES; RISES AB Over 500 coronae occur on Venus. A recent survey defined Type 2 coronae as those with <50% complete fracture annuli. This paper synthesizes the results from a statistical study of the size, topographic morphology and geologic setting of the entire corona population and a study of the gravity and topography of the 32 Type 2 coronae resolved in the gravity data. Using the estimated lithospheric properties, loading signature, and geologic characteristics, we examine the factors controlling corona morphology, size and fracture completeness (Type 1 versus Type 2). We find no difference between lithospheric properties in the plains and fractures belts. Nearly half of the Type 2 coronae studied are isostatically compensated, and probably inactive. This implies that the final stage of a corona may have a wide range of topographic morphologies. Elastic thickness has no correlation with diameter and therefore does not limit corona size. The ratio of crustal thickness to plume diameter does not control morphology as a function of size, as predicted by a spreading drop model. However, rim-only coronae, which are predicted to form via isostatic rebound of crust thickened by delamination, are supported by a density interface. Isostasy and delamination of the lower lithosphere are likely to have a greater effect on corona formation, and possibly in understanding the evolution of the Venusian lithosphere, than variations in elastic thickness. The role of isostasy in the formation of Type 2 coronae suggests that surface fractures may be reduced due to low strain rates. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Proxemy Res, Laytonsville, MD 20882 USA. RP Smrekar, SE (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,Mail Stop 183-501, Pasadena, CA 91109 USA. NR 42 TC 9 Z9 9 U1 0 U2 0 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 AUG 15 PY 2003 VL 108 IS E8 AR 5091 DI 10.1029/2002JE001930 PG 10 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 713QN UT WOS:000184869600002 ER PT J AU Burlaga, LF Ness, NF Richardson, JD AF Burlaga, LF Ness, NF Richardson, JD TI Sectors in the distant heliosphere: Voyager 1 and 2 observations from 1999 through 2002 between 57 and 83 AU SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article DE heliospheric magnetic field; sectors; sector zone; solar wind; Voyager ID INTERPLANETARY MAGNETIC-FIELD; CURRENT SHEET; OUTER HELIOSPHERE; SOLAR MAXIMUM; ULYSSES; POLARITY; CORONA; WIND; MHD AB Sectors and sector boundaries were observed by Voyager 1 (V1) and Voyager 2 (V2) from 1999 through 2002 in the distant heliosphere. V1 moved from a heliocentric distance R = 72.5 to 83.4 AU and from a latitude of delta = 33.4degrees to 33.8degrees from 1999.0 to 2002.0, and V2 moved from R = 56.7 to 69.0 AU and from delta = -20.2degrees to -24.1degrees from 1999.0 to 2003.0. During some time intervals, sectors were not present, and during much of the time the data were not sufficiently accurate to determine whether or not sectors were present. Nevertheless, some sectors do persist out to 83 AU, even in the interval surrounding the solar maximum. A regular sector pattern was not observed by either V1 or V2 in any of the years from 1999 through 2002. The sector sizes are highly variable, and they are not consistent with either a two-sector pattern or a four-sector pattern. The sector pattern observed at 1 AU by ACE was presumably destroyed by stream interactions and by transient ejecta that moved through the heliosphere. Observations of the solar wind speed made by V2 from 1999 to 2002 show a jump-ramp structure, as expected from previous observational and theoretical studies. The jump-ramp structures are much larger than the sectors. The speed jumps occur within some of the sectors, not at the sector boundaries. C1 NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. Univ Delaware, Bartol Res Inst, Newark, DE 19711 USA. MIT, Ctr Space Res, Cambridge, MA 02139 USA. RP Burlaga, LF (reprint author), NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. NR 38 TC 25 Z9 25 U1 0 U2 0 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 AUG 15 PY 2003 VL 108 IS A10 AR 8028 DI 10.1029/2003JA009870 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 713QY UT WOS:000184870500001 ER PT J AU Garcia, LN Fung, SF Green, JL Boardsen, SA Sandel, BR Reinisch, BW AF Garcia, LN Fung, SF Green, JL Boardsen, SA Sandel, BR Reinisch, BW TI Observations of the latitudinal structure of plasmaspheric convection plumes by IMAGE-RPI and EUV SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article DE plasmasphere; plasmapause; inner magnetosphere; convection plumes; RPI; EUV ID RADIO PLASMA IMAGER; EXTREME-ULTRAVIOLET IMAGER; DENSITY; REGIONS; MODEL; MAGNETOSPHERE; MISSION; FIELD; TAIL AB Recent IMAGE Extreme Ultraviolet Imager (EUV) observations showed the first global images of plasmaspheric convection plumes, which have been interpreted as the plasmaspheric tails predicted theoretically 3 decades earlier. Using observations by the IMAGE Radio Plasma Imager (RPI), we show that these convection plumes have large latitudinal extent. These results complement those recently made by others in correlating IMAGE EUV data with measurements of total electron content in the ionosphere. By correlating in situ RPI density measurements with global plasmaspheric EUV images, we have shown that apparently detached plasma structures, as appear in RPI dynamic spectrograms, are in many cases plasmaspheric convection plumes. The temporal separation between the RPI and EUV observations help constrain the interpretation of one data set in the context of the other, thereby enabling an examination of the three-dimensional plasma density structures outside the core plasmasphere. The data sets are mutually reinforcing because the data are collected within a few hours of one another. We used the EUV data to provide unambiguous identification of density enhancements in the region outside the plasmasphere and used the RPI data to obtain accurate number densities and extend information from the EUV data set by measuring densities below the EUV sensitivity threshold. C1 NASA, Goddard Space Flight Ctr, QSS Grp Inc, Greenbelt, MD 20771 USA. QSS Grp Inc, Lanham, MD USA. L3 Commun EER Syst Inc, Largo, MD USA. Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. Univ Massachusetts, Ctr Atmospher Res, Lowell, MA 01854 USA. RP Garcia, LN (reprint author), NASA, Goddard Space Flight Ctr, QSS Grp Inc, Code 630, Greenbelt, MD 20771 USA. RI Fung, Shing/F-5647-2012 NR 27 TC 17 Z9 17 U1 0 U2 0 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 AUG 15 PY 2003 VL 108 IS A8 AR 1321 DI 10.1029/2002JA009496 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 713QV UT WOS:000184870200001 ER PT J AU Pryor, WR Ajello, JM McComas, DJ Witte, M Tobiska, WK AF Pryor, WR Ajello, JM McComas, DJ Witte, M Tobiska, WK TI Hydrogen atom lifetimes in the three-dimensional heliosphere over the solar cycle SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article DE interplanetary hydrogen; solar wind; interstellar wind; charge-exchange; Ulysses ID INTERPLANETARY LYMAN-ALPHA; INTER-STELLAR WIND; GALILEO ULTRAVIOLET SPECTROMETER; NEUTRAL-GAS EXPERIMENT; INTERSTELLAR HYDROGEN; PIONEER-VENUS; MASS FLUX; LATITUDINAL VARIATIONS; PLANETARY EMISSION; CHARGE-EXCHANGE AB The three-dimensional (3-D) structure of the heliosphere is investigated using in situ and remote sensing measurements. The 3-D structure of both neutral interplanetary gas and solar wind ions are affected by the solar latitude variation of the solar radiation fields (solar wind and solar EUV). Neutral hydrogen atom lifetimes against charge-exchange with solar wind protons in the 3-D heliosphere are calculated from measurements of the solar wind proton velocity, density, and mass flux by Ulysses SWOOPS (Solar Wind Observations Over the Poles of the Sun) from 1990-2001. These are compared to in-ecliptic H atom lifetimes derived from solar wind measurements by the spacecraft IMP (Interplanetary Monitoring Platform) 6, 7, and 8, WIND, and ACE (Advanced Composition Explorer) SWEPAM (Solar Wind Electron Proton Alpha Monitor). Recent observations during the Ulysses rapid solar pole-to-solar pole passage (fast-latitude scan) at solar maximum find a more isotropic rotationally averaged solar wind mass flux (and H atom lifetime) than was found during the previous fast latitude scan at solar minimum. During the solar minimum fast-latitude scan the 27-day averaged SWOOPS lifetime passed through two distinct regimes: it doubled from 2 x 10(6) s at low latitudes to 4 x 10(6) s at high latitudes in both hemispheres. During the solar maximum pass the 27-day averaged SWOOPS H atom lifetime (corrected to 1 AU) at all southern latitudes and at all northern latitudes below 60degrees was (2-2.5) x 10(6) s, while at the very end of the pass, above 60degrees N latitude, it rose to 4 x 10(6) s as polar coronal holes reformed. Remote sensing studies of interplanetary H Lyman-alpha emission, white light solar coronal observations, and radio scintillation experiments have also indicated that the time-averaged solar wind mass flux (and H atom lifetime) is more isotropic at solar maximum than at solar minimum. This enlarges the polar H cavity at solar maximum. Results from in situ measurements are compared to remote sensing data. Ulysses GAS Lyman-alpha maps are modeled, with updated results. Comparisons of the H atom charge exchange loss rate with a weaker H atom loss process, photoionization, are made using the SOLAR2000 model [Tobiska et al., 2000] for in-ecliptic solar Extreme UltraViolet (EUV) fluxes. The relative latitude invariance of the H atom lifetime at solar maximum is related to the absence of high-speed solar wind at solar maximum and to the large inclination of the heliospheric current sheet. C1 Hampton Univ, Ctr Atmospher Sci, Hampton, VA 23668 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. SW Res Inst, Space Sci & Engn Div, San Antonio, TX 78238 USA. Max Planck Inst Aeron, D-47191 Katlenburg Lindau, Germany. Space Environm Technol SpaceWx Div, Los Angeles, CA USA. RP Pryor, WR (reprint author), Hampton Univ, Ctr Atmospher Sci, 23 Tyler St, Hampton, VA 23668 USA. NR 68 TC 10 Z9 10 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-SPACE JI J. Geophys. Res-Space Phys. PD AUG 15 PY 2003 VL 108 IS A10 AR 8034 DI 10.1029/2003JA009878 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 713QY UT WOS:000184870500003 ER PT J AU Cruden, BA Meyyappan, M AF Cruden, BA Meyyappan, M TI Corrected equations for membrane transport characterization by manometric techniques SO JOURNAL OF MEMBRANE SCIENCE LA English DT Article DE membrane transport characterization; manometric techniques; integral method; time-lag technique; transport parameters ID PARAMETERS AB Equations for characterization of membrane permeability and diffusivity via pressure decay measurements in closed and open systems for three different configurations are discussed in terms of time lag and general transient solutions. The solutions presented correct errors in the earlier work of Nguyen et al. (C) 2003 Elsevier B.V. All rights reserved. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Cruden, BA (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 5 TC 3 Z9 3 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0376-7388 J9 J MEMBRANE SCI JI J. Membr. Sci. PD AUG 15 PY 2003 VL 221 IS 1-2 BP 47 EP 51 DI 10.1016/S0376-7388(03)00191-1 PG 5 WC Engineering, Chemical; Polymer Science SC Engineering; Polymer Science GA 716NT UT WOS:000185035800003 ER PT J AU Dowling, JP Milburn, GJ AF Dowling, JP Milburn, GJ TI Quantum technology: the second quantum revolution SO PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES LA English DT Article DE quantum technology; quantum information; nanotechnology, quantum optics, mesoscopics; atom optics ID NEUTRAL ATOMS; COMPUTATION; COMPUTER; LASER; INTERFEROMETRY; VIOLATION; PHOTONS; FUTURE; OPTICS; DEVICE AB We are currently in the midst of a second quantum revolution. The first quantum revolution gave us new rules that govern physical reality. The second quantum revolution will take these rules and use them to develop new technologies. In this review we discuss the principles upon which quantum technology is based and the tools required to develop it. We discuss a number of examples of research programs that could deliver quantum technologies in coming decades including: quantum information technology, quantum electromechanical systems, coherent quantum electronics, quantum optics and coherent matter technology. C1 Quantum Comp Technol Grp, Sect 367, Jet Propuls Lab, Pasadena, CA 91109 USA. Univ Cambridge, Dept Appl Math & Theoret Phys, Cambridge CB3 0WA, England. Univ Queensland, Ctr Quantum Comp Technol, St Lucia, Qld 4072, Australia. RP Quantum Comp Technol Grp, Sect 367, Jet Propuls Lab, Pasadena, CA 91109 USA. RI MIlburn, Gerard/B-6381-2008; DOWLING, JONATHAN/L-2749-2013 OI MIlburn, Gerard/0000-0002-5404-9681; NR 77 TC 110 Z9 110 U1 3 U2 20 PU ROYAL SOC PI LONDON PA 6-9 CARLTON HOUSE TERRACE, LONDON SW1Y 5AG, ENGLAND SN 1364-503X EI 1471-2962 J9 PHILOS T R SOC A JI Philos. Trans. R. Soc. A-Math. Phys. Eng. Sci. PD AUG 15 PY 2003 VL 361 IS 1809 BP 1655 EP 1674 DI 10.1098/rsta.2003.1227 PG 20 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 715CA UT WOS:000184951900006 PM 12952679 ER PT J AU Greene, PB Kadota, K Murayama, H AF Greene, PB Kadota, K Murayama, H TI Supergravity inflation free from harmful relics SO PHYSICAL REVIEW D LA English DT Article ID DYNAMICAL SUPERSYMMETRY BREAKING; ENTROPY CRISIS; GRAVITINO; SYMMETRY; POLONYI; MODELS; AXION AB We present a realistic supergravity inflation model that is free from the overproduction of potentially dangerous relics in cosmology, namely, moduli and gravitinos, which can lead to inconsistencies with the predictions of baryon asymmetry and nucleosynthesis. The radiative correction turns out to play a crucial role in our analysis, raising the mass of the supersymmetry breaking field to an intermediate scale. We pay particular attention to the nonthermal production of gravitinos using the nonminimal Kahler potential we obtained from loop correction. This nonthermal gravitino production is diminished, however, because of the relatively small scale of the inflaton mass and the small amplitudes of the hidden sector fields. C1 Fermilab Natl Accelerator Lab, NASA, Fermilab Astrophys Grp, Batavia, IL 60510 USA. Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Theory Grp, Berkeley, CA 94720 USA. RP Fermilab Natl Accelerator Lab, NASA, Fermilab Astrophys Grp, POB 500, Batavia, IL 60510 USA. RI Murayama, Hitoshi/A-4286-2011 NR 26 TC 7 Z9 7 U1 0 U2 0 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2470-0010 EI 2470-0029 J9 PHYS REV D JI Phys. Rev. D PD AUG 15 PY 2003 VL 68 IS 4 AR 043502 DI 10.1103/PhysRevD.68.043502 PG 9 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 719ZM UT WOS:000185235500014 ER PT J AU Otterman, J Atlas, R Russell, GL Saaroni, H AF Otterman, J Atlas, R Russell, GL Saaroni, H TI Impact on regional winter climate by CO2 increases vs. by maritime-air advection SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID TROPOSPHERIC TEMPERATURE; NORTH-ATLANTIC; SURFACE; TRENDS; EUROPE AB Fractional Outgoing Radiation, FOR (dimensionless), defined as the ratio of Outgoing Longwave Radiation, OLR (W/m(2)), to upward Surface Longwave Emission, SLE (W/m(2)), is a basic parameter for analyzing regional greenhouse effect. Here, FOR values are derived from a General Circulation Model by extracting OLR and SLE over areas in east-central Europe (at about 60degreesN) one hour after injecting appropriate CO2 concentration (adjustments to the atmospheric profile are thus excluded) to the Feb. 1 midnight simulation. The reduction in FOR is 0.00051 when atmospheric CO2 increases by 14 ppm, which is the currently expected per-decade increase. Fluctuations in the North-Atlantic surface winds produce fluctuations in FOR over central Europe: monthly-mean FOR in strong-wind February 1990 was 0.679, but 0.758 in weak-wind, lower cloud-fraction February 1996. Strong maritime-air advection in 1990 resulted thus in FOR reduced by 0.079, effect by two orders-of-magnitude stronger than the decrease effected by the per-decade increase in CO2. C1 NASA, Goddard Space Flight Ctr, Data Assimilat Off, LAOR, Greenbelt, MD 20771 USA. NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Tel Aviv Univ, Dept Geog & Human Environm, IL-69978 Tel Aviv, Israel. RP Otterman, J (reprint author), NASA, Goddard Space Flight Ctr, Data Assimilat Off, LAOR, Code 910-3, Greenbelt, MD 20771 USA. RI Atlas, Robert/A-5963-2011 OI Atlas, Robert/0000-0002-0706-3560 NR 11 TC 0 Z9 0 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 AUG 14 PY 2003 VL 30 IS 15 AR 1822 DI 10.1029/2003GL017545 PG 3 WC Geosciences, Multidisciplinary SC Geology GA 713PQ UT WOS:000184867500001 ER PT J AU Oreopoulos, L Khairoutdinov, M AF Oreopoulos, L Khairoutdinov, M TI Overlap properties of clouds generated by a cloud-resolving model SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE clouds; radiative transfer; overlap; cloud-resolving models; general circulation models; cloud parameterization ID RADAR DATA; STATISTICS AB The overlap properties of similar to850 snapshots of convective cloud fields generated by a cloud-resolving model are studied and compared with previously published results based on cloud radar observations. Total cloud cover is overestimated by the random overlap assumption but underestimated by the maximum overlap assumption and two standard implementations of the combined maximum/random overlap assumption. When the overlap of two layers is examined as a function of vertical separation distance, the value of the parameter alpha measuring the relative weight of maximum (alpha=1) and random (alpha=0) overlap decreases in such a way that only layers less than 1 km apart can be considered maximally overlapped, while layers more than 5 km apart are essentially randomly overlapped. The decrease of alpha with separation distance Deltaz is best expressed by a power law, which may not, however, be suitable for parameterization purposes. The more physically appropriate exponential function has slightly smaller goodness of fit overall but still gives very good fits for Deltaz between 0 and 5 km, which is the range of separation distances that would be of most importance in any overlap parameterization for radiative transfer purposes. C1 Univ Maryland Baltimore Cty, Joint Ctr Earth Syst Technol, Baltimore, MD 21250 USA. NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. Colorado State Univ, Dept Atmospher Sci, Ft Collins, CO 80523 USA. RP Univ Maryland Baltimore Cty, Joint Ctr Earth Syst Technol, 1000 Hilltop Circle, Baltimore, MD 21250 USA. EM lazaros@climate.gsfc.nasa.gov RI Oreopoulos, Lazaros/E-5868-2012 OI Oreopoulos, Lazaros/0000-0001-6061-6905 NR 13 TC 23 Z9 24 U1 0 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 AUG 14 PY 2003 VL 108 IS D15 AR 4479 DI 10.1029/2002JD003329 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 713PY UT WOS:000184868200002 ER PT J AU Xie, SP Xie, Q Wang, DX Liu, WT AF Xie, SP Xie, Q Wang, DX Liu, WT TI Summer upwelling in the South China Sea and its role in regional climate variations SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article DE upwelling; air-sea interaction; orographically induced wind jet; ocean stationary eddy; South China Sea; climate variability ID UPPER-LAYER CIRCULATION; SURFACE TEMPERATURE; OCEAN CIRCULATION; INDIAN-OCEAN; TROPICAL PACIFIC; ALTIMETER DATA; SATELLITE; TOPEX/POSEIDON; MONSOON; DYNAMICS AB Seasonal and interannual variations of summer upwelling off the South Vietnam coast and the offshore spread of cold water are investigated using a suite of new satellite measurements. In summer, as the southwesterly winds impinge on Annam Cordillera (a north-south running mountain range on the east coast of Indochina) a strong wind jet occurs at its southern tip offshore east of Saigon, resulting in strong wind curls that are important for ocean upwelling off the coast. In July and August an anticyclonic ocean eddy develops to the southeast, advecting the cold coastal water offshore into the open South China Sea (SCS). The center of this cold filament is located consistently north of the wind speed maximum, indicating that open-ocean upwelling helps to cool the ocean surface. Corroborating evidence for the cold filament is found in ocean color observations that reveal a collocated tongue of high chlorophyll concentration. The development of this cold filament disrupts the summer warming of the SCS and causes a pronounced semiannual cycle in SST. Moreover, the cold filament is an important player in interannual variability in the summer SCS. In 1998, the cold filament and mid-summer cooling never took place, giving rise to a strong basin-wide surface warming. Interannual SST variance has a local maximum over the climatological cold filament, and is much greater than the variance over the adjacent Indian and western Pacific Oceans. A cold filament index is constructed, which displays significant lagged correlation with SST in the eastern equatorial Pacific and Indian Oceans, indicative of a teleconnection from El Nino. C1 Univ Hawaii, SOEST, Int Pacific Res Ctr, Honolulu, HI 96822 USA. Univ Hawaii, Dept Meteorol, Honolulu, HI 96822 USA. Chinese Acad Sci, S China Sea Inst Oceanol, LED, Guangzhou 510301, Peoples R China. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Xie, SP (reprint author), Univ Hawaii, SOEST, Int Pacific Res Ctr, Honolulu, HI 96822 USA. EM xie@hawaii.edu; gordonxie@scsio.ac.cn; dxwang@scsio.ac.cn; liu@pacific.jpl.nasa.gov RI Xie, Shang-Ping/C-1254-2009; WANG, DongXiao/B-4445-2012 OI Xie, Shang-Ping/0000-0002-3676-1325; NR 41 TC 241 Z9 284 U1 8 U2 76 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 AUG 14 PY 2003 VL 108 IS C8 AR 3261 DI 10.1029/2003JC001867 PG 13 WC Oceanography SC Oceanography GA 713QJ UT WOS:000184869200001 ER PT J AU Johnson, PV Kanik, I Shemansky, DE Liu, X AF Johnson, PV Kanik, I Shemansky, DE Liu, X TI Electron-impact cross sections of atomic oxygen SO JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS LA English DT Article ID ULTRAVIOLET EMISSION; MOLECULAR-HYDROGEN; RYDBERG SERIES; EXCITATION; TRANSITIONS; RESOLUTION; VALUES; H-2; NM AB We report electron-impact-induced emission cross sections for the 2p(4) P-3-3s (3)Sdegrees (130.4 nm), 2p 4 P-3-3d (3)Ddegrees (102.7 nm), 2p(4) P-3-3s' (3)Ddegrees (98.9 nm) and 2p(4) P-3-3s" 3Pdegrees (87.8 nm) transitions of atomic oxygen. Measurements were made using a magnetically confined electron beam in collision with atomic oxygen produced by an extended microwave discharge source in a crossed-beam arrangement. A 0.2 m vacuum ultraviolet diffraction spectrometer was used to record the emission. The absolute excitation functions of these transitions were determined by normalizing to the O I (130.4 nm) cross section produced by dissociative excitation Of O-2 at 100 eV impact energy (Noren et al 2001 a Geophys. Res. Lett. 28 1379). A 60-state model of the O I electron reaction structure has been used to extract the excitation cross sections from the experimental measurements. The model process establishes analytic collision strengths to the asymptotic limit. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ So Calif, Dept Aerosp & Mech Engn, Los Angeles, CA 90089 USA. RP Johnson, PV (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Johnson, Paul/D-4001-2009 OI Johnson, Paul/0000-0002-0186-8456 NR 25 TC 16 Z9 16 U1 0 U2 3 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0953-4075 J9 J PHYS B-AT MOL OPT JI J. Phys. B-At. Mol. Opt. Phys. PD AUG 14 PY 2003 VL 36 IS 15 BP 3203 EP 3218 AR PII S0953-4075(03)59199-4 DI 10.1088/0953-4075/36/15/303 PG 16 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 718PU UT WOS:000185156300004 ER PT J AU Cadez, I Greenwood, JB Lozano, J Mawhorter, RJ Niimura, M Smith, SJ Chutjian, A AF Cadez, I Greenwood, JB Lozano, J Mawhorter, RJ Niimura, M Smith, SJ Chutjian, A TI Absolute cross sections for single and double charge-exchange in Feq+ impacting on He SO JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS LA English DT Article ID ELECTRON-CAPTURE; SOLAR-WIND; ATOMIC-HYDROGEN; X-RAYS; COLLISIONS; IONS; CONSTRAINTS; VELOCITIES; H-2; H+ AB We report measured absolute single and double charge-exchange cross sections (CSs) for Feq+ ions with He at the ion impact energy of 7.0 x q keV for q = 5-13. The range of ion velocities is 350 km s(-1) for q = 5, to 560 km s(-1) for q = 13, comparable to typical solar wind velocities. A retarding-field method is used for charge-state analysis of the ion beam after traversing the stationary target gas cell. The CSs are determined from absolute measurements of the ion currents and He target gas pressure. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Jozef Stefan Inst, Dhaka 1000, Bangladesh. Queens Univ Belfast, Dept Phys, Belfast BT7 1NN, Antrim, North Ireland. Pomona Coll, Dept Phys & Astron, Claremont, CA 91711 USA. RP Cadez, I (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Greenwood, Jason/L-4799-2014 NR 25 TC 12 Z9 12 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0953-4075 J9 J PHYS B-AT MOL OPT JI J. Phys. B-At. Mol. Opt. Phys. PD AUG 14 PY 2003 VL 36 IS 15 BP 3303 EP 3314 AR PII S0953-4075(03)60553-5 DI 10.1088/0953-4075/36/15/311 PG 12 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 718PU UT WOS:000185156300012 ER PT J AU Sinnhuber, M Burrows, JP Chipperfield, MP Jackman, CH Kallenrode, MB Kunzi, KF Quack, M AF Sinnhuber, M Burrows, JP Chipperfield, MP Jackman, CH Kallenrode, MB Kunzi, KF Quack, M TI A model study of the impact of magnetic field structure on atmospheric composition during solar proton events SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID COSMIC-RAY EVENTS; MIDDLE ATMOSPHERE; PARTICLE-PRECIPITATION; STRATOSPHERE; SIMULATIONS; MESOSPHERE; NITROGEN; OXYGEN; OZONE; AIR AB During a polarity transition of the Earth's magnetic field, the structure and strength of the field change significantly from their present values. This will alter the global pattern of charged particle precipitation into the atmosphere. Thus, particle precipitation is possible into regions that are at the moment effectively shielded by the Earth's magnetic field. A two-dimensional global chemistry, photolysis and transport model of the atmosphere has been used to investigate how the increased particle precipitation affects the chemical composition of the middle and lower atmosphere. Ozone losses resulting from large energetic particle events are found to increase significantly, with resultant losses similar to those observed in the Antarctic ozone hole of the 1990s. This results in significant increases in surface UV-B radiation as well as changes in stratospheric temperature and circulation over a period of several months after large particle events. C1 Univ Bremen, Inst Environm Phys, D-2800 Bremen 33, Germany. Univ Leeds, Sch Environm, Leeds LS2 9JT, W Yorkshire, England. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Osnabruck, D-4500 Osnabruck, Germany. RP Sinnhuber, M (reprint author), Univ Bremen, Inst Environm Phys, D-2800 Bremen 33, Germany. RI Sinnhuber, Miriam/A-7252-2013; Chipperfield, Martyn/H-6359-2013; Jackman, Charles/D-4699-2012; Burrows, John/B-6199-2014 OI Chipperfield, Martyn/0000-0002-6803-4149; Burrows, John/0000-0002-6821-5580 NR 23 TC 31 Z9 31 U1 1 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 AUG 13 PY 2003 VL 30 IS 15 AR 1818 DI 10.1029/2003GL017265 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 713PP UT WOS:000184867400002 ER PT J AU Siskind, DE Stevens, MH Emmert, JT Drob, DP Kochenash, AJ Russell, JM Gordley, LL Mlynczak, MG AF Siskind, DE Stevens, MH Emmert, JT Drob, DP Kochenash, AJ Russell, JM Gordley, LL Mlynczak, MG TI Signatures of shuttle and rocket exhaust plumes in TIMED/SABER radiance data SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID RESOLUTION DOPPLER IMAGER; SATELLITE AB We have searched the 6.8 mm water vapor radiance data obtained from the Sounding of the Atmosphere with Broadband Emission Radiometry (SABER) on the Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED) satellite for evidence of rocket plumes. Between 94-130 km, significant radiance enhancements are occasionally seen which correspond in time and space to emission from the exhaust plumes of the space shuttle and various unmanned liquid-fueled rockets. Over a 10 month period in 2002 (Feb-Nov), SABER detected about 40% of the total liquid fueled launches, including four out of four space shuttle launches. The shuttle plumes are seen at and below 115 km, while the unmanned rocket plumes extend to higher altitudes. The meridional transport of the shuttle plumes near 110 km suggests a dependence upon the local time of the launch with plumes from mid-day launches traveling to the N and plumes from late afternoon and evening launches traveling to the S. C1 USN, Res Lab, EO Hulburt Ctr Space Res, Washington, DC 20375 USA. Computat Phys Inc, Fairfax, VA USA. Hampton Univ, Hampton, VA 23668 USA. GATS Inc, Newport News, VA USA. NASA, Langley Res Ctr, Hampton, VA 23665 USA. RP Siskind, DE (reprint author), USN, Res Lab, EO Hulburt Ctr Space Res, Code 7640, Washington, DC 20375 USA. RI Mlynczak, Martin/K-3396-2012; Drob, Douglas/G-4061-2014 OI Drob, Douglas/0000-0002-2045-7740 NR 13 TC 15 Z9 15 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 AUG 13 PY 2003 VL 30 IS 15 AR 1819 DI 10.1029/2003GL017627 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 713PP UT WOS:000184867400003 ER PT J AU Le, G Huang, CS Pfaff, RF Su, SY Yeh, HC Heelis, RA Rich, FJ Hairston, M AF Le, G Huang, CS Pfaff, RF Su, SY Yeh, HC Heelis, RA Rich, FJ Hairston, M TI Plasma density enhancements associated with equatorial spread F: ROCSAT-1 and DMSP observations SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article DE plasma density enhancements; equatorial spread F; plasma depletions; equatorial ionosphere; ionospheric irregularities; plasma waves and instabilities ID LOW LATITUDE IONOSPHERE; HINOTORI SATELLITE; IMPEDANCE PROBE; BUBBLES; IRREGULARITIES; EVOLUTION; ALTITUDE; BOARD AB Large-scale plasma density depletions are typically associated with equatorial spread F (ESF) plasma irregularities in the nightside F region, especially in the postsunset sector. Data gathered on the ROCSAT-1 spacecraft reveal numerous cases of localized, discrete plasma density enhancements in the nightside low-latitude region at similar to600 km altitude. In some cases, nearly simultaneous DMSP observations at similar to800 km reveal similar density enhancements in the same local time sector. These density enhancement structures occur in association with ESF plasma depletions, i.e., the density enhancements are observed in the same local time where ESF plasma depletions are also present simultaneously. Within these discrete structures, the plasma density may be enhanced by similar to2-3 times above the background density. The density enhancement regions have sharp, distinct edges with embedded irregularities that appear to have similar scale sizes and density fluctuation spectra as those typically found in plasma depletions. Examples studied here occur at local times about 3 hours after sunset near the equatorial anomaly region, similar to10degrees to 20degrees from the magnetic equator. The ion velocity data within the density enhancement regions show upward plasma drifts perpendicular to the magnetic field, similar to those within adjacent plasma depletion regions. The magnetic field-aligned plasma flows are generally poleward within the density enhancement regions. The observations suggest that density enhancement structures are caused by the polarization electric field which is generated within the equatorial plasma depletions and then maps to the higher latitudes along the magnetic field lines. C1 NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Electrodynam Branch, Greenbelt, MD 20771 USA. MIT, Haystack Observ, Westford, MA 01886 USA. Natl Cent Univ, Inst Space Sci, Chungli 320, Taiwan. Univ Texas, William B Hanson Ctr Space Sci, Richardson, TX 75083 USA. USAF, Res Lab, Space Vehicles Directorate, Hanscom AFB, MA 01731 USA. RP Le, G (reprint author), NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Electrodynam Branch, Code 696, Greenbelt, MD 20771 USA. RI Le, Guan/C-9524-2012; Pfaff, Robert/F-5703-2012; OI Le, Guan/0000-0002-9504-5214; Pfaff, Robert/0000-0002-4881-9715; Hairston, Marc/0000-0003-4524-4837 NR 22 TC 39 Z9 40 U1 0 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 AUG 13 PY 2003 VL 108 IS A8 AR 1318 DI 10.1029/2002JA009592 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 713QU UT WOS:000184870100001 ER PT J AU Castro, SL Bailey, SG Raffaelle, RP Banger, KK Hepp, AF AF Castro, SL Bailey, SG Raffaelle, RP Banger, KK Hepp, AF TI Nanocrystalline chalcopyrite materials (CuInS2 and CuInSe2) via low-temperature pyrolysis of molecular single-source precursors SO CHEMISTRY OF MATERIALS LA English DT Article ID ELEMENTAL SOLVOTHERMAL REACTION; FILM SOLAR-CELLS; OPTICAL-PROPERTIES; THIN-FILMS; QUANTUM DOTS; SEMICONDUCTOR; NANOPARTICLES; ROUTE; NANORODS; EFFICIENCY AB Nanometer-sized particles of the chalcopyrite compounds CuInS2 and CuInSe2 were synthesized by thermal decomposition of molecular single-source precursors (PPh3)(2)CuIn(SEt)(4) and (PPh3)(2)CuIn(SePh)(4), respectively, in the noncoordinating solvent dioctyl phthalate at temperatures between 200 and 300 degreesC. The nanoparticles range in size from 3 to 30 nm and are aggregated to form roughly spherical clusters of about 500 nm in diameter. X-ray diffraction of the nanoparticle powders shows greatly broadened lines, indicative of very small particle sizes, which is confirmed by TEM. Peaks present in the XRD can be indexed to reference patterns for the respective chalcopyrite compounds. Optical spectroscopy and elemental analysis by energy dispersive spectroscopy support the identification of the nanoparticles as chalcopyrites. C1 NASA, Glenn Res Ctr, Photovoltaics & Space Environm Branch, Cleveland, OH 44135 USA. Ohio Aerosp Inst, Cleveland, OH 44142 USA. Rochester Inst Technol, Dept Phys, Rochester, NY 14623 USA. RP Castro, SL (reprint author), NASA, Glenn Res Ctr, Photovoltaics & Space Environm Branch, Mail Stop 302-1,21000 Brookpark Rd, Cleveland, OH 44135 USA. NR 54 TC 279 Z9 289 U1 17 U2 109 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 AUG 12 PY 2003 VL 15 IS 16 BP 3142 EP 3147 DI 10.1021/cm034161o PG 6 WC Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA 710LF UT WOS:000184681100013 ER PT J AU Uritsky, VM Klimas, AJ Vassiliadis, D AF Uritsky, VM Klimas, AJ Vassiliadis, D TI Evaluation of spreading critical exponents from the spatiotemporal evolution of emission regions in the nighttime aurora SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID SELF-ORGANIZED CRITICALITY; INNER MAGNETOTAIL; ABSORBING STATES; FLOW BURSTS; BRIGHTENINGS; INJECTIONS; SUBSTORM; SYSTEMS AB Recently, it has been found that the spatiotemporal evolution of auroral emission regions, as depicted by the ultraviolet imager (UVI) onboard the POLAR spacecraft, follows well-defined power law statistical relations characteristic of complex systems near criticality [Uritsky et al., 2002b]. In this study, we continue our investigation of scaling features in the auroral emissions with emphasis on their dynamical characteristics. Based on an analysis of more than 6,700 emission events, we estimate the so-called spreading critical exponents that govern the mean field evolution of localized perturbations in nonequilibrium systems with spatially extended degrees of freedom. We show that the auroral emissions display scale-free spreading behavior that manifests itself through characteristic power-law auroral emission area dynamics. The spreading exponents so obtained are consistent with scaling relations predicted for self-organized criticality. C1 NASA, Goddard Space Flight Ctr, Univ Space Res Assoc, Greenbelt, MD 20771 USA. St Petersburg State Univ, Inst Phys, St Petersburg, Russia. RP Uritsky, VM (reprint author), NASA, Goddard Space Flight Ctr, Univ Space Res Assoc, Code 692, Greenbelt, MD 20771 USA. EM uritsky@geo.phys.spbu.ru; Alex.Klimas@nasa.gov; vassi@electra.gsfc.nasa.gov NR 16 TC 29 Z9 29 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 AUG 12 PY 2003 VL 30 IS 15 AR 1813 DI 10.1029/2002GL016556 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 713PN UT WOS:000184867300001 ER PT J AU Bosilovich, MG Sud, YC Schubert, SD Walker, GK AF Bosilovich, MG Sud, YC Schubert, SD Walker, GK TI Numerical simulation of the large-scale North American monsoon water sources SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE North American monsoon; precipitation recycling; regional water cycle; monsoon simulation; Great Plains; Mexico ID SEA-SURFACE TEMPERATURES; COMMUNITY-CLIMATE-MODEL; 1993 MIDWESTERN FLOOD; CENTRAL UNITED-STATES; LOW-LEVEL JET; INTERANNUAL VARIABILITY; MEXICAN MONSOON; REMOTE SOURCES; PRECIPITATION; GULF AB A general circulation model that includes water vapor tracer (diagnostics is used to delineate the dominant sources of water vapor for precipitation during the North American monsoon. A 15-year model simulation carried out with 1-degree horizontal resolution and time-varying sea surface temperature is able to produce reasonable large-scale features of the monsoon precipitation. Within the core of the Mexican monsoon, continental sources provide much of the water for precipitation. Away from the Mexican monsoon (eastern Mexico and Texas), continental sources generally decrease with monsoon onset. Tropical Atlantic Ocean sources of water gain influence in the southern Great Plains states, where the total precipitation decreases during the monsoon onset. Pacific Ocean sources do contribute to the monsoon but tend to be weaker after onset. Evaluating the development of the monsoons, soil water and surface evaporation prior to monsoon onset do not correlate with the eventual monsoon intensity. However, the most intense monsoons do use more local sources of water than the least intense monsoons, but only after the onset. This suggests that precipitation recycling is an important factor in monsoon intensity. C1 NASA, Global Modeling & Assimilat Off, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NASA, Climate & Radiat Branch, GSFC, Greenbelt, MD 20771 USA. RP Bosilovich, MG (reprint author), NASA, Global Modeling & Assimilat Off, Goddard Space Flight Ctr, Code 900-3, Greenbelt, MD 20771 USA. EM michael.bosilovich@nasa.gov RI Bosilovich, Michael/F-8175-2012 NR 38 TC 33 Z9 34 U1 0 U2 3 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 AUG 12 PY 2003 VL 108 IS D16 AR 8614 DI 10.1029/2002JD003095 PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 713QA UT WOS:000184868400002 ER PT J AU Maslov, AV Ning, CZ AF Maslov, AV Ning, CZ TI Reflection of guided modes in a semiconductor nanowire laser SO APPLIED PHYSICS LETTERS LA English DT Article AB We analyze the waveguiding properties of semiconductor (GaN, ZnO, CdS) single nanowire lasers which were recently demonstrated experimentally. In particular, we compute the reflectivity for a few lowest-order guided modes (HE11, TE01, and TM01) from the nanowire facets. The reflectivity is shown to depend strongly on the mode type, lasing frequency and radius of the nanowire. By using the computed reflectivities, we make realisic estimates of the threshold gain and quality factor for the nanowire lasers. Our results shed light on the lasing mechanism of the nanowire lasers. (C) 2003 American Institute of Physics. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Eloret Corp, Sunnyvale, CA 94087 USA. RP Maslov, AV (reprint author), NASA, Ames Res Ctr, MS 229-1, Moffett Field, CA 94035 USA. 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 7 TC 157 Z9 161 U1 4 U2 66 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 AUG 11 PY 2003 VL 83 IS 6 BP 1237 EP 1239 DI 10.1063/1.1599037 PG 3 WC Physics, Applied SC Physics GA 708QV UT WOS:000184580600060 ER PT J AU Bowman, RC AF Bowman, RC TI Development of metal hydride beds for sorption cryocoolers in space applications SO JOURNAL OF ALLOYS AND COMPOUNDS LA English DT Article; Proceedings Paper CT 8th International Symposium on Metal-Hydrogen Systems, Fundamentals and Applications (MH2002) CY SEP 02-06, 2002 CL ANNECY, FRANCE DE hydrogen storage materials; gas-solid reactions; heat conduction ID DEGRADATION; HYDROGEN AB The development of hydrogen sorption cryocoolers over the past 30 years is briefly reviewed. The behavior of the metal hydride sorbent beds used in the sorption compressors dominates both the performance and reliability of these closed-cycle Joule-Thomson cryocoolers. Improved compressor elements have been recently designed to minimize their input power requirements and to enhance hydride durability during extended temperature cycling while in operation. ZrNi hydride is used to provide variable gas pressure in the gas-gap heat switches for each compressor element. Characterization tests have been performed on the compressor elements built for an engineering breadboard (EBB) cryocooler to evaluate the behavior of both the sorbent bed and gas-gap switches under conditions simulating flight operation for the future Planck mission of the European Space Agency (ESA). Operation of the Planck EBB sorption cryocooler has produced a cooling capacity of 1.0-1.7 W at a temperature of 17.7 K during initial laboratory tests. (C) 2003 Elsevier B.V. All rights reserved. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,Mail Stop 79-24, Pasadena, CA 91109 USA. EM robert.c.bowman-jr@jpl.nasa.gov OI Bowman, Robert/0000-0002-2114-1713 NR 18 TC 27 Z9 28 U1 0 U2 6 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0925-8388 EI 1873-4669 J9 J ALLOY COMPD JI J. Alloy. Compd. PD AUG 11 PY 2003 VL 356 BP 789 EP 793 DI 10.1016/S0925-8388(03)00089-6 PG 5 WC Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Chemistry; Materials Science; Metallurgy & Metallurgical Engineering GA 711DU UT WOS:000184725000169 ER PT J AU Sandrock, G Bowman, RC AF Sandrock, G Bowman, RC TI Gas-based hydride applications: recent progress and future needs SO JOURNAL OF ALLOYS AND COMPOUNDS LA English DT Article; Proceedings Paper CT 8th International Symposium on Metal-Hydrogen Systems, Fundamentals and Applications (MH2002) CY SEP 02-06, 2002 CL ANNECY, FRANCE DE hydrogen storage materials; gas-solid reactions; metal hydride applications ID HYDROGEN HEAT-PUMP; METAL-HYDRIDE; SEPARATION; RECOVERY; STORAGE; OPTIMIZATION; ABSORPTION; DEUTERIUM; KINETICS; CATALYST AB Hydride applications can be cataloged under five main categories: H, storage, thermal compression (including closed thermodynamic systems), gas separation, electrochemical and processing and miscellaneous. Recent commercial and R&D hydride applications activities are reviewed herein (excluding the NiMH battery). Growing interest in fuel cell power has stimulated interest in hydride storage of H-2 with good near-term commercial potential in the subcategories of stationary, small portable and on-board vehicular storage. The competition for vehicular hydride storage is high pressure compressed H, held in lightweight composite cylinders. If hydrides are to compete, we must develop radical new concepts to substantially increase the gravimetric capacity at low desorption temperatures. Published by Elsevier B.V. C1 SunaTech Inc, Ringwood, NJ 07456 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Sandrock, G (reprint author), SunaTech Inc, 113 Kraft Pl, Ringwood, NJ 07456 USA. OI Bowman, Robert/0000-0002-2114-1713 NR 62 TC 49 Z9 49 U1 0 U2 12 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0925-8388 J9 J ALLOY COMPD JI J. Alloy. Compd. PD AUG 11 PY 2003 VL 356 BP 794 EP 799 DI 10.1016/S0925-8388(03)00090-2 PG 6 WC Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Chemistry; Materials Science; Metallurgy & Metallurgical Engineering GA 711DU UT WOS:000184725000170 ER PT J AU Willingale, R Hands, ADP Warwick, RS Snowden, SL Burrows, DN AF Willingale, R Hands, ADP Warwick, RS Snowden, SL Burrows, DN TI The X-ray spectrum of the North Polar Spur SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE ISM : bubbles; ISM : structure; X-rays : ISM ID SPECTROMETER; DETECTORS; MAPS AB An analysis is presented of the soft X-ray background spectrum measured by the EPIC-MOS cameras on XMM-Newton in three observations targeted on the North Polar Spur (NPS). Three distinct Galactic plasma components are identified: a cool local hot bubble (LHB) component, T (lo) similar to 0.1 keV; a cool Galactic halo component, at a similar temperature; and a hotter component, T (hi) similar to 0.26 keV, associated with the NPS itself. Using the new data in combination with the ROSAT All-Sky Survey count rates measured in the 0.1-0.4 keV band, we estimate the emission measure of the LHB material to be 0.0040-0.0052 cm(-6) pc, which implies an electron density of 0.008-0.011 cm(-3) and pressure of similar to22 000 cm(-3) K. The halo and NPS components lie behind at least 50 per cent of the line-of-sight cold gas for which the total Galactic column density is in the range (2-8) x 10(20) cm(-2). Modelling the X-ray emitting superbubble as a sphere at distance 210 pc, radius 140 pc and centre l (II) = 352degrees, b (II) = 15degrees, the implied electron density in the NPS is similar to0.03 cm(-3) with pressure similar to150 000 cm(-3) K. The observed spectral line complexes from O vii, O viii, Fe xvii, Ne ix, Ne x and Mg xi provide constraints on the composition of the plasma. The hot component in the NPS is depleted in oxygen, neon and, to some extent, magnesium and iron. Assuming that the effective line of sight across the halo emission is 1 kpc, the electron density in the halo is 0.007-0.011 cm(-3) and the pressure is similar to16 500 cm(-3) K, conditions very similar to those in the LHB. C1 Univ Leicester, Dept Phys & Astron, Leicester LE1 7RH, Leics, England. NASA, Univ Space Res Assoc, GSFC, LHEA, Greenbelt, MD 20771 USA. Penn State Univ, Dept Astron & Astrophys, Davey Lab 525, University Pk, PA 16802 USA. RP Willingale, R (reprint author), Univ Leicester, Dept Phys & Astron, Univ Rd, Leicester LE1 7RH, Leics, England. RI Snowden, Steven/D-5292-2012 NR 19 TC 39 Z9 39 U1 1 U2 2 PU BLACKWELL PUBLISHING LTD PI OXFORD PA 9600 GARSINGTON RD, OXFORD OX4 2DG, OXON, ENGLAND SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD AUG 11 PY 2003 VL 343 IS 3 BP 995 EP 1001 DI 10.1046/j.1365-8711.2003.06741.x PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 706ZT UT WOS:000184485500034 ER PT J AU Awwal, AA Iftekharuddin, KM Karim, MA Juday, RD AF Awwal, AA Iftekharuddin, KM Karim, MA Juday, RD TI Optical pattern recognition algorithms, architecture, and applications: introduction to the feature issue SO APPLIED OPTICS LA English DT Editorial Material AB This issue of Applied Optics features eight papers in the areas of optical pattern recognition. They range from new algorithms for improved classification, rotation and scale invariant recognition to novel architectures and applications of optical correlation filters in information processing. (C) 2003 Optical Society of America. C1 Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. Univ Memphis, Memphis, TN 38152 USA. CUNY City Coll, New York, NY 10031 USA. NASA, Johnson Space Ctr, Johnson City, TN USA. RP Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. EM awwall@llnl.gov; iftekhar@memphis.edu; karim@engr.ccny.cuny.edu; richard_juday@prodigy.net NR 0 TC 1 Z9 1 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 AUG 10 PY 2003 VL 42 IS 23 BP 4647 EP 4648 DI 10.1364/AO.42.004647 PG 2 WC Optics SC Optics GA 711LP UT WOS:000184742500001 ER PT J AU Markowitz, A Edelson, R Vaughan, S Uttley, P George, IM Griffiths, RE Kaspi, S Lawrence, A McHardy, I Nandra, K Pounds, K Reeves, J Schurch, N Warwick, R AF Markowitz, A Edelson, R Vaughan, S Uttley, P George, IM Griffiths, RE Kaspi, S Lawrence, A McHardy, I Nandra, K Pounds, K Reeves, J Schurch, N Warwick, R TI X-ray fluctuation power spectral densities of Seyfert 1 galaxies SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : active; galaxies : Seyfert; X-rays : galaxies ID ACTIVE GALACTIC NUCLEI; LOW-LUMINOSITY STATES; BLACK-HOLE; TIMING ANALYSIS; ACCRETION DISK; TIME LAGS; VARIABILITY; EMISSION; MCG-6-30-15; NOISE AB By combining complementary monitoring observations spanning long, medium, and short timescales, we have constructed power spectral densities (PSDs) of six Seyfert 1 galaxies. These PSDs span greater than or similar to4 orders of magnitude in temporal frequency, sampling variations on timescales ranging from tens of minutes to over a year. In at least four cases, the PSD shows a "break,'' a significant departure from a power law, typically on timescales of the order of a few days. This is similar to the behavior of Galactic X-ray binaries (XRBs), lower mass compact systems with breaks on timescales of seconds. NGC 3783 shows tentative evidence for a doubly broken power law, a feature that until now has been seen only in the ( much better defined) PSDs of low-state XRBs. It is also interesting that ( when one previously observed object is added to make a small sample of seven) an apparently significant correlation is seen between the break timescale T and the putative black hole mass M-BH, while none is seen between break timescale and luminosity. The data are consistent with the linear relation T = M-BH/10(6.5) M-.; extrapolation over 6 - 7 orders of magnitude is in reasonable agreement with XRBs. All of this strengthens the case for a physical similarity between Seyfert 1 galaxies and XRBs. C1 Univ Calif Los Angeles, Dept Astron, Los Angeles, CA 90095 USA. Univ Cambridge, Inst Astron, Cambridge CB3 0HA, England. Univ Southampton, Dept Phys & Astron, Southampton SO17 1BJ, Hants, England. Univ Maryland Baltimore Cty, Dept Phys, Joint Ctr Astrophys, Baltimore, MD 21250 USA. NASA, High Energy Astrophys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Carnegie Mellon Univ, Dept Phys, Pittsburgh, PA 15213 USA. Tel Aviv Univ, Raymond & Beverly Sackler Fac Exact Sci, Sch Phys & Astron, IL-69978 Tel Aviv, Israel. Tel Aviv Univ, Raymond & Beverly Sackler Fac Exact Sci, Wise Observ, IL-69978 Tel Aviv, Israel. Univ Edinburgh, Royal Observ, Inst Astron, Edinburgh EH9 3HJ, Midlothian, Scotland. Univ London Imperial Coll Sci Technol & Med, Blackett Lab, Astrophys Grp, London SW7 2BW, England. Univ Leicester, Xray Astron Grp, Leicester LE1 7RH, Leics, England. RP Markowitz, A (reprint author), Univ Calif Los Angeles, Dept Astron, Los Angeles, CA 90095 USA. NR 66 TC 187 Z9 187 U1 0 U2 1 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 AUG 10 PY 2003 VL 593 IS 1 BP 96 EP 114 DI 10.1086/375330 PN 1 PG 19 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 708TN UT WOS:000184585600008 ER PT J AU McKernan, B Yaqoob, T George, IM Turner, TJ AF McKernan, B Yaqoob, T George, IM Turner, TJ TI The kinematics and physical conditions of the ionized gas in NGC 4593 from Chandra high-energy grating spectroscopy SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : active; galaxies : individual (NGC 4593); galaxies : Seyfert; techniques : spectroscopic; X-rays : galaxies ID ACTIVE GALACTIC NUCLEI; DUSTY WARM ABSORBER; X-RAY-SPECTRUM; IRON LINE; SEYFERT-1 GALAXIES; ASCA OBSERVATIONS; EMISSION; ABSORPTION; VARIABILITY; MCG-6-30-15 AB We observed the Seyfert 1 galaxy NGC 4593 with the Chandra high-energy transmission gratings and present a detailed analysis of the soft X-ray spectrum. We measure strong absorption lines from He-like O, Ne, Mg, Si, H-like N, O, Ne, Mg, Si, and highly ionized Fe xix - Fe xxv. The weighted mean of the offset velocity of the strongest absorption profiles is - 140 +/- 35 km s(-1). However, the individual profiles are consistent with the systemic velocity of NGC 4593, and many profiles hint at the presence of either multiple kinematic components or blending. Only the N vii Lyalpha (lambda24.781), O viii Lyalpha (lambda18.969), and Mg xii Lyalpha (lambda8.421) lines appear to be marginally resolved. We identify a spectral feature at similar to 0.707 keV with a neutral Fe L edge, which might suggest that there is dust along the line of sight to NGC 4593, although this is not the only interpretation of this feature. A search for neutral O absorption, which would reasonably be expected from dust absorption, is complicated by contamination of the Chandra ACIS CCDs. Neutral Si absorption, which might also be expected from absorption due to dust, is present ( though not significantly) in the form of a weak neutral Si edge. The neutral Si column (< 4 x 10(17) cm(-2)) corresponding to the Si edge is consistent with the neutral Fe column (&SIM;1.5 x 10(17) cm(-2)) from the Fe L edge. We also detect, at marginal significance, N vii Lyα (λ24.781) and O vii (r) 1s(2) - 1s2p (λ21.602) absorption at z &SIM; 0, due to a hot medium in our Local Group. The soft X-ray spectrum of NGC 4593 is adequately described by a simple single-zone photoionized absorber with an equivalent hydrogen column density of 5.37(-0.79)(+1.45) x 10(21) cm(-2) and an ionization parameter of log xi = 2.52(-0.04)(+0.06) ergs cm s(-1), although there remain some features that are not identified. Although the photoionized gas almost certainly is composed of matter in more than one ionization state and may consist of several kinematic components, data with better signal-to-noise ratio and better spectral resolution are required to justify a more complex model. Finally, in emission we detect only weak forbidden lines of [ Ne ix] and [O vii]. C1 Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. NASA, High Energy Astrophys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Maryland Baltimore Cty, Joint Ctr Astrophys, Baltimore, MD 21250 USA. RP McKernan, B (reprint author), Johns Hopkins Univ, Dept Phys & Astron, 3400 N Charles St, Baltimore, MD 21218 USA. NR 31 TC 24 Z9 24 U1 0 U2 1 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 AUG 10 PY 2003 VL 593 IS 1 BP 142 EP 159 DI 10.1086/376555 PN 1 PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 708TN UT WOS:000184585600011 ER PT J AU Pannuti, TG Allen, GE Houck, JC Sturner, SJ AF Pannuti, TG Allen, GE Houck, JC Sturner, SJ TI RXTE, ROSAT, and ASCA observations of G347.3-0.5 (RX J1713.7-3946): Probing cosmic-ray acceleration by a Galactic shell-type supernova remnant SO ASTROPHYSICAL JOURNAL LA English DT Article DE acceleration of particles; cosmic rays; supernova remnants; X-rays : individual (G347.3-0.5; Galactic ridge) ID NONLINEAR SHOCK ACCELERATION; GAS IMAGING SPECTROMETER; CASSIOPEIA-A; X-RAYS; PARTICLE-ACCELERATION; MOLECULAR CLOUDS; MAXIMUM ENERGIES; LINE EMISSION; ELECTRONS; SN-1006 AB We present an analysis of the X-ray spectrum of the Galactic shell-type supernova remnant (SNR) G347.3-0.5 (RX J1713.7-3946). This SNR is a member of a growing class of dynamically young, shell-type SNRs that emit nonthermal X-rays from specific regions on their outer shells. By performing a joint spectral analysis of data from observations made of G347.3-0.5 using the ROSAT PSPC, the ASCA GIS, and the RXTE PCA, we have fitted the spectra of particular regions of this SNR (including the bright northwestern and southwestern rims, the northeast rim, and the interior diffuse emission) over the approximate energy range of 0.5-30 keV. We find that fits to the spectra of this SNR over this energy range using the SRCUT model were superior to a simple power-law model or the SRESC model. We also find that the inclusion of a thermal model with the SRCUT model helps to improve the fit to the observed X-ray spectrum: this represents the first detection of thermal X-ray emission from G347.3-0.5. Thermal emission appears to be more clearly associated with the diffuse emission in the interior of the SNR than with the bright X-ray-emitting rims. A weak emission feature seen near 6.4 keV in the RXTE PCA spectrum most likely originates from diffuse X-ray emission from the surrounding Galactic ridge rather than from G347.3-0.5 itself. We have analyzed our RXTE PCA data to search for pulsations from a recently discovered radio pulsar (PSR J1713-3949) which may be associated with G347.3-0.5, and we do not detect any X-ray pulsations at the measured radio period of 392 ms. Using the best-fit parameters obtained from the SRCUT model, we estimate the maximum energy of cosmic-ray electrons accelerated by the rims of G347.3-0.5 to be 36-48 TeV (assuming a magnetic field strength of B = 10 muG). We present a broadband (radio to gamma-ray) photon energy-flux spectrum for the northwestern rim of G347.3-0.5, where we have fitted the spectrum using a more sophisticated synchrotron-inverse Compton model with a variable magnetic field strength. Our fit derived from this model yields a maximum energy of only 8.8(-3.4)(+4.1) TeV for the accelerated cosmic-ray electrons and a much greater magnetic field strength of 150(-80)(+250) muG; however, our derived ratio of volumes for TeV emission and X-ray emission based on this fit, V-TeV/VX-ray approximate to 1000, is too large to be physically acceptable. We argue that neither nonthermal bremsstrahlung nor neutral pion particle decay can adequately explain the TeV emission from this rim, and therefore the physical process responsible for this emission at this site is currently uncertain. Finally, we compare the gross properties of G347.3-0.5 with other SNRs known to possess X-ray spectra dominated by nonthermal emission. C1 MIT, Ctr Space Res, Cambridge, MA 02139 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Space Res Assoc, Lanham, MD 20706 USA. RP Pannuti, TG (reprint author), MIT, Ctr Space Res, 77 Massachusetts Ave, Cambridge, MA 02139 USA. NR 58 TC 33 Z9 33 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 AUG 10 PY 2003 VL 593 IS 1 BP 377 EP 392 DI 10.1086/376498 PN 1 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 708TN UT WOS:000184585600029 ER PT J AU Musielak, ZE Noble, M Porter, JG Winget, DE AF Musielak, ZE Noble, M Porter, JG Winget, DE TI Chandra observations of magnetic white dwarfs and their theoretical implications SO ASTROPHYSICAL JOURNAL LA English DT Article DE stars : coronae; stars : magnetic fields; white dwarfs; X-rays : stars ID X-RAY-EMISSION; ALL-SKY SURVEY; DYNAMO GENERATION; UPPER LIMIT; FIELDS; ROSAT; STARS; CATALOG; ATMOSPHERES; SINGLE AB Observations of cool DA and DB white dwarfs have not yet been successful in detecting coronal X-ray emission, but observations of late-type dwarfs and giants show that coronae are common for these stars. To produce coronal X-rays, a star must have dynamo-generated surface magnetic fields and a well-developed convection zone. There is some observational evidence that the DA star LHS 1038 and the DB star GD 358 have weak and variable surface magnetic fields. It has been suggested that such fields can be generated by dynamo action, and since both stars have well-developed convection zones, theory predicts detectable levels of coronal X-rays from these white dwarfs. However, we present analysis of Chandra observations of both stars showing no detectable X-ray emission. The derived upper limits for the X-ray fluxes provide strong constraints on theories of formation of coronae around magnetic white dwarfs. Another important implication of our negative Chandra observations is the possibility that the magnetic fields of LHS 1038 and GD 358 are fossil fields. C1 Univ Texas, Dept Phys, Arlington, TX 76019 USA. NASA, George C Marshall Space Flight Ctr, SD 50, Huntsville, AL 35812 USA. Univ Texas, Dept Astron, Austin, TX 78712 USA. Univ Texas, McDonald Observ, Austin, TX 78712 USA. RP Musielak, ZE (reprint author), Univ Texas, Dept Phys, POB 19059, Arlington, TX 76019 USA. NR 38 TC 8 Z9 8 U1 0 U2 1 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 AUG 10 PY 2003 VL 593 IS 1 BP 481 EP 485 DI 10.1086/376407 PN 1 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 708TN UT WOS:000184585600038 ER PT J AU Falconer, DA Moore, RL Porter, JG Hathaway, DH AF Falconer, DA Moore, RL Porter, JG Hathaway, DH TI Solar coronal heating and the magnetic flux content of the network SO ASTROPHYSICAL JOURNAL LA English DT Article DE Sun : corona; Sun : magnetic fields; Sun : UV radiation ID X-RAY TELESCOPE; ACTIVE REGIONS; TRANSITION REGION; EXPLOSIVE EVENTS; BRIGHT POINTS; ENERGY-FLOW; HOLES; SPICULES; FIELDS; MASS AB We investigate the heating of the quiet corona by measuring the increase of coronal luminosity with the amount of magnetic flux in the underlying network at solar minimum when there were no active regions on the face of the Sun. The coronal luminosity is measured from Fe IX/X-Fe XII pairs of coronal images from SOHO/EIT, under the assumption that practically all of the coronal luminosity in our quiet regions comes from plasma in the temperature range 0.9 x 10(6) K less than or equal to T less than or equal to 1.3 x 10(6) K. The network magnetic flux content is measured from SOHO/MDI magnetograms. We find that the luminosity of the corona in our quiet regions increases roughly in proportion to the square root of the magnetic flux content of the network and roughly in proportion to the length of the perimeter of the network magnetic flux clumps. From (1) this result, (2) other observations of many fine-scale explosive events at the edges of network flux clumps, and (3) a demonstration that it is energetically feasible for the heating of the corona in quiet regions to be driven by explosions of granule-sized sheared-core magnetic bipoles embedded in the edges of network flux clumps, we infer that in quiet regions that are not influenced by active regions the corona is mainly heated by such magnetic activity in the edges of the network flux clumps. Our observational results together with our feasibility analysis allow us to predict that (1) at the edges of the network flux clumps there are many transient sheared-core bipoles of the size and lifetime of granules and having transverse field strengths greater than similar to100 G, (2) similar to30 of these bipoles are present per supergranule, and (3) most spicules are produced by explosions of these bipoles. C1 NASA, George C Marshall Space Flight Ctr, Dept Space Sci, Huntsville, AL 35812 USA. RP Univ Alabama, Dept Phys, Huntsville, AL 35899 USA. EM david.falconer@msfc.nasa.gov; ron.moore@nasa.gov; jason.porter@nasa.gov; david.h.hathaway@nasa.gov NR 62 TC 14 Z9 15 U1 0 U2 1 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 AUG 10 PY 2003 VL 593 IS 1 BP 549 EP 563 DI 10.1086/376359 PN 1 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 708TN UT WOS:000184585600043 ER PT J AU Shaposhnikov, N Titarchuk, L Haberl, F AF Shaposhnikov, N Titarchuk, L Haberl, F TI The bursting behavior of 4U 1728-34: The parameters of a neutron star and the geometry of a neutron star-disk system SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; stars : fundamental parameters; stars : individual (4U 1728-34); X-rays : bursts ID X-RAY-BURSTS; QUASI-PERIODIC OSCILLATIONS; LOW-FREQUENCY; 4U 1728-34; MASS; EXPANSION; DISTANCE; FEATURES; SPECTRA AB We analyze a set of type I X-ray bursts from the low-mass X-ray binary 4U 1728-34, observed with the Rossi X-Ray Timing Explorer. We infer the dependence of the neutron star (NS) mass and radius with respect to the assumed distance to the system using an analytical model of X-ray burst spectral formation. The model behavior clearly indicates that the burster atmosphere is dominated by helium. Our results strongly favor the soft equation of state of the NS for 4U 1728-34. We find that the distance to the source should be within the 4.5-5.0 kpc range. We obtain rather narrow constrains for the NS radius in the 8.7-9.7 km range and in the 1.2-1.6 M. interval for the NS mass for this particular distance range. We uncover a temporal behavior of redshift-corrected burst flux for the radial expansion episodes, and we put forth a dynamical evolution scenario for the NS-accretion disk geometry during which an expanded envelope affects the accretion disk and increases the area of the NS exposed to the Earth observer. In the framework of this scenario, we provide a new method for the estimation of the inclination angle that leads to the value of similar to50degrees for 4U 1728-34. C1 George Mason Univ, Ctr Earth Observing & Space Res, Fairfax, VA 22030 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Max Planck Inst Extraterr Phys, D-85748 Garching, Germany. RP Shaposhnikov, N (reprint author), George Mason Univ, Ctr Earth Observing & Space Res, Fairfax, VA 22030 USA. NR 19 TC 17 Z9 17 U1 0 U2 1 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 AUG 10 PY 2003 VL 593 IS 1 BP L35 EP L38 DI 10.1086/378255 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 708TR UT WOS:000184585900009 ER PT J AU Strohmayer, TE AF Strohmayer, TE TI Phase coherent timing of RX J0806.3+1527 with ROSAT and Chandra SO ASTROPHYSICAL JOURNAL LA English DT Article DE binaries : close; gravitational waves; stars : individual (RX J0806.3+1527; RX J1914.4+2456); white dwarfs; X-rays : binaries ID DOUBLE-DEGENERATE POLAR; GRAVITATIONAL-RADIATION; RX J0806.3+1527; RAY-EMISSION; BINARY; SYSTEMS; PULSAR AB RX J0806.3+1527 is an ultracompact, double-degenerate binary with the shortest known orbital period (321.5 s). Hakala et al. have recently reported new optical measurements of the orbital frequency of the source indicating that the frequency has increased over the approximate to9 yr since the earliest ROSAT observations. They find two candidate solutions for the long-term change in the frequency (nu) over dot approximate to 3 or 6 x 10(-16) Hz s(-1). Here we present the results of a phase coherent timing study of the archival ROSAT and Chandra data for RX J0806.3+1527 in the light of these new constraints. We find that the ROSAT-Chandra timing data are consistent with both of the solutions reported by Hakala et al. but that the higher (nu) over dot = 6.1 x 10(-16) Hz s(-1) solution is favored at the approximate to97% level. This large (nu) over dot can be accommodated by an approximate to1 M. detached double-degenerate system powered in the X-ray by electrical. energy (Wu et al.). With such a large (nu) over dot, the system provides a unique opportunity to explore the interaction of gravitational radiation and electromagnetic torques on the evolution of an ultracompact binary. C1 NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Strohmayer, TE (reprint author), NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Mail Code 662, Greenbelt, MD 20771 USA. NR 19 TC 23 Z9 23 U1 0 U2 1 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 AUG 10 PY 2003 VL 593 IS 1 BP L39 EP L42 DI 10.1086/378061 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 708TR UT WOS:000184585900010 ER PT J AU Bourras, D Liu, WT AF Bourras, D Liu, WT TI Regional correction of ocean surface specific humidity derived from satellite sensor data SO INTERNATIONAL JOURNAL OF REMOTE SENSING LA English DT Article ID LATENT-HEAT FLUX; SEMAPHORE AB A method is proposed to increase the accuracy of satellite sensor-derived near-surface humidity estimates. The method uses an operational atmospheric circulation model to correct the satellite sensor estimates of humidity from their regional bias. The method was applied to twelve orbits of the Special Sensor Microwave/Imager (SSM/I) selected between 1997 and 1998. The SSM/I-derived humidity estimates were corrected with respect to analyses of the European Centre for Medium-Range Weather Forecasts (ECMWF) model. The SSM/I humidities were compared to observations of the Comprehensive Ocean-Atmosphere Data Set (COADS), before and after correction with respect to the ECMWF products. The results show that the proposed method decreased the rms. error between SSM/I and COADS specific humidity by 20%. Independent application of the method in the context of a field experiment indicated that the deviation between satellite sensor-derived humidity and in situ observations was decreased by 13% if the correction was applied. C1 Univ Paris 06, Lab Oceanog Dynam & Climatol, UMR 7617, F-75252 Paris 05, France. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Bourras, D (reprint author), Univ Paris 06, Lab Oceanog Dynam & Climatol, UMR 7617, LODYC Boite 100,4 Pl Jussieu, F-75252 Paris 05, France. NR 9 TC 0 Z9 0 U1 0 U2 0 PU TAYLOR & FRANCIS LTD PI ABINGDON PA 4 PARK SQUARE, MILTON PARK, ABINGDON OX14 4RN, OXON, ENGLAND SN 0143-1161 J9 INT J REMOTE SENS JI Int. J. Remote Sens. PD AUG 10 PY 2003 VL 24 IS 15 BP 3163 EP 3169 DI 10.1080/0143116031000090678 PG 7 WC Remote Sensing; Imaging Science & Photographic Technology SC Remote Sensing; Imaging Science & Photographic Technology GA 700TW UT WOS:000184128100011 ER PT J AU Kaul, UK AF Kaul, UK TI New boundary constraints for elliptic systems used in grid generation problems SO JOURNAL OF COMPUTATIONAL PHYSICS LA English DT Article DE new boundary constraints; automated elliptic grid generation; decay parameters; Neumann boundary conditions; conservation of thermal energy ID ARBITRARY 2-DIMENSIONAL BODIES; NUMERICAL GENERATION; NUMBER AB New boundary constraints for elliptic partial differential equations as used in grid generation problems in generalized curvilinear coordinate systems are proposed in this paper. These constraints, based on the principle of local conservation of thermal energy in the vicinity of the boundaries, are derived using the Green's Theorem. They uniquely determine the so called decay parameters in the inhomogeneous terms of these elliptic systems. These constraints I are designed for boundary clustered grids where large gradients in physical quantities need to be resolved adequately. It is observed that the present formulation also works satisfactorily for mild clustering. Therefore, a closure for the decay parameter specification for elliptic grid generation problems has been provided resulting in a fully automated elliptic grid generation technique. Thus, there is no need for a parametric study of these decay parameters since the new constraints fix them uniquely. It is also shown that for Neumann type boundary conditions, these boundary constraints uniquely determine the solution to the internal elliptic problem thus eliminating the nominiqueness of the solution of an internal boundary value grid generation problem with Neumann boundary conditions. (C) 2003 Elsevier Science B.V. All rights reserved. C1 NASA, Ames Res Ctr, Div Comp Sci, Moffett Field, CA 94035 USA. RP NASA, Ames Res Ctr, Div Comp Sci, Moffett Field, CA 94035 USA. EM kaul@email.arc.nasa.gov NR 13 TC 9 Z9 10 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 0021-9991 EI 1090-2716 J9 J COMPUT PHYS JI J. Comput. Phys. PD AUG 10 PY 2003 VL 189 IS 2 BP 476 EP 492 DI 10.1016/S0021-9991(03)00229-8 PG 17 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA 713ZW UT WOS:000184888700007 ER PT J AU Goldstein, ME AF Goldstein, ME TI A generalized acoustic analogy SO JOURNAL OF FLUID MECHANICS LA English DT Article ID TURBULENT MIXING LAYER; LARGE-SCALE STRUCTURES; JET NOISE; HARMONIC PERTURBATIONS; COHERENT STRUCTURES; SOUND; COMPUTATION; GENERATION; RADIATION; FLOWS AB The purpose of this article is to show that the Navier-Stokes equations can be rewritten as a set of linearized inhomogeneous Euler equations (in convective form) with source terms that are exactly the same as those that would result from externally imposed shear-stress and energy-flux perturbations. These results are used to develop a mathematical basis for some existing and potential new jet noise models by appropriately choosing the 'base flow' about which the linearization is carried out. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Goldstein, ME (reprint author), NASA, Glenn Res Ctr, 21000 Brookpk Rd, Cleveland, OH 44135 USA. NR 51 TC 109 Z9 112 U1 1 U2 11 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 40 WEST 20TH ST, NEW YORK, NY 10011-4221 USA SN 0022-1120 J9 J FLUID MECH JI J. Fluid Mech. PD AUG 10 PY 2003 VL 488 BP 315 EP 333 DI 10.1017/S0022112003004890 PG 19 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA 720JQ UT WOS:000185258000011 ER PT J AU Gregg, WW Conkright, ME Ginoux, P O'Reilly, JE Casey, NW AF Gregg, WW Conkright, ME Ginoux, P O'Reilly, JE Casey, NW TI Ocean primary production and climate: Global decadal changes SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID PACIFIC-OCEAN; CHLOROPHYLL; PHYTOPLANKTON; CYCLE; CO2 AB Satellite-in situ blended ocean chlorophyll records indicate that global ocean annual primary production has declined more than 6% since the early 1980's. Nearly 70% of the global decadal decline occurred in the high latitudes. In the northern high latitudes, these reductions in primary production corresponded with increases in sea surface temperature and decreases in atmospheric iron deposition to the oceans. In the Antarctic, the reductions were accompanied by increased wind stress. Three of four low latitude basins exhibited decadal increases in annual primary production. These results indicate that ocean photosynthetic uptake of carbon may be changing as a result of climatic changes and suggest major implications for the global carbon cycle. C1 NASA, Goddard Space Flight Ctr, Lab Hydrospher Proc, Greenbelt, MD 20771 USA. NOAA, Natl Oceanog Data Ctr, Ocean Climate Lab, Silver Spring, MD 20910 USA. Princeton Univ, NOAA, Geophys Fluid Dynam Lab, Princeton, NJ 08542 USA. NOAA, Natl Marine Fisheries Serv, Narragansett Lab, Narragansett, RI 02882 USA. Sci Syst & Applicat Inc, Lanham, MD 20706 USA. RP Gregg, WW (reprint author), NASA, Goddard Space Flight Ctr, Lab Hydrospher Proc, Greenbelt, MD 20771 USA. RI Ginoux, Paul/C-2326-2008 OI Ginoux, Paul/0000-0003-3642-2988 NR 21 TC 148 Z9 151 U1 0 U2 49 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 AUG 9 PY 2003 VL 30 IS 15 AR 1809 DI 10.1029/2003GL016889 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 712PA UT WOS:000184805000001 ER PT J AU Hess, RA MacDowall, RJ AF Hess, RA MacDowall, RJ TI Scattering of interplanetary radio waves at kilometric wavelengths SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article DE radio wave scattering; solar wind; Jovian nKOM; electron density fluctuations; interplanetary turbulence ID ELECTRON-DENSITY FLUCTUATIONS; SOLAR-WIND; OUTER HELIOSPHERE; PROPAGATION; PLASMA; SCINTILLATION; TURBULENCE; SPECTRUM; SUN; SPACECRAFT AB [1] We report on measurements of the angular size of Jovian radio sources measured by the URAP instrument on the Ulysses spacecraft. The angular size is found to be substantially larger than that expected from the geometric size of the source, which is essentially a point source when viewed from Ulysses. This increase in size is due to scattering of the radio waves caused by fluctuations in the electron density along the path of the radiation. The angular size varies with wavelength as expected for such scattering, and the magnitude of the scattering is in rough agreement with, though less than, results of previous investigations in the slow solar wind. The magnitude of the scattering is found to vary substantially for different radio events, most likely due to changes in the density and/or fluctuation level along the path of the radiation. These measurements are especially suited to determining scattering parameters as the source is point-like and precisely located. Our results confirm that interplanetary scattering imposes important constraints on low-frequency radio observations by new spacecraft missions. C1 L3 Commun EER Syst Inc, Vienna, VA USA. NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. RP Hess, RA (reprint author), NASA, Goddard Space Flight Ctr, Code 695, Greenbelt, MD 20771 USA. RI MacDowall, Robert/D-2773-2012 NR 26 TC 0 Z9 0 U1 0 U2 0 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 AUG 8 PY 2003 VL 108 IS A8 AR 1313 DI 10.1029/2002JA009783 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 712YM UT WOS:000184827200003 ER PT J AU Mielke, SL Peterson, KA Schwenke, DW Garrett, BC Truhlar, DG Michael, JV Su, MC Sutherland, JW AF Mielke, SL Peterson, KA Schwenke, DW Garrett, BC Truhlar, DG Michael, JV Su, MC Sutherland, JW TI H+H-2 thermal reaction: A convergence of theory and experiment SO PHYSICAL REVIEW LETTERS LA English DT Article ID POTENTIAL-ENERGY SURFACE; SHOCK TUBE TECHNIQUE; RATE CONSTANTS; TEMPERATURE-RANGE; CHEMICAL-KINETICS; HYDROGEN MOLECULE; ESR DETECTION; GROUND-STATE; H-3; PHOTOLYSIS AB New experimental and theoretical rate constants for two isotopologs of the simplest chemical reaction, H+H-2-->H-2+H, are presented. The theoretical results are obtained using accurate quantum dynamics with a converged Born-Oppenheimer potential energy surface and include non-Born-Oppenheimer corrections. The new experiments are carried out using a shock tube and complement earlier investigations over a very large T range, 167 to 2112 K. Experiment and theory now agree perfectly, within experimental error, bringing this 75-year-old scientific problem to completion. C1 Pacific NW Natl Lab, Richland, WA 99352 USA. Washington State Univ, Dept Chem, Pullman, WA 99164 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ Minnesota, Dept Chem, Minneapolis, MN 55455 USA. Argonne Natl Lab, Div Chem, Argonne, IL 60439 USA. RP Mielke, SL (reprint author), Pacific NW Natl Lab, Richland, WA 99352 USA. RI Michael, Joe/E-3907-2010; Garrett, Bruce/F-8516-2011; Mielke, Steven/B-7533-2008; schwenke, david/I-3564-2013; Truhlar, Donald/G-7076-2015 OI Mielke, Steven/0000-0002-1938-7503; Truhlar, Donald/0000-0002-7742-7294 NR 53 TC 94 Z9 96 U1 2 U2 23 PU AMER 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 AUG 8 PY 2003 VL 91 IS 6 AR 063201 DI 10.1103/PhysRevLett.91.063201 PG 4 WC Physics, Multidisciplinary SC Physics GA 710JZ UT WOS:000184678200015 PM 12935072 ER PT J AU Duncan, BN Bey, I Chin, M Mickley, LJ Fairlie, TD Martin, RV Matsueda, H AF Duncan, BN Bey, I Chin, M Mickley, LJ Fairlie, TD Martin, RV Matsueda, H TI Indonesian wildfires of 1997: Impact on tropospheric chemistry SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Review DE Indonesia; biomass burning; wildfires; aerosols; radiative forcing; long-range transport ID GROUND-BASED OBSERVATIONS; BIOMASS BURNING SMOKE; LONG-RANGE TRANSPORT; 1997-1998 EL-NINO; CARBON-MONOXIDE; FOREST-FIRES; OPTICAL-PROPERTIES; TOMS MEASUREMENTS; DEEP CONVECTION; MAUNA-LOA AB The Indonesian wildfires of 1997 released large amounts of trace gases and aerosols (e.g., similar to130 Tg of carbon monoxide (CO)) from September to November. Using the GEOS-CHEM model of tropospheric chemistry and transport, we conducted a study of this burning event, including sensitivity simulations, to estimate the impacts of the trace gas and aerosol emissions on tropospheric chemistry. The emissions from the fires were estimated using the Total Ozone Mapping Spectrometer (TOMS) Aerosol Index (AI) data product and fire-count data from the Along Track Scanning Radiometer (ATSR) World Fire Atlas as surrogates for biomass burning. The model captures most of the daily variations of CO and ozone (O-3) observed in the region affected by the pollution. Export of the pollution from the Indonesian region was primarily in the prevailing easterlies in the free troposphere to the tropical Indian Ocean where the bulk of the pollution lay between 20degreesN to 20degreesS from September to November. The model's tropospheric CO and O3 columns were elevated by more than 50% and 10%, respectively, over the tropical Indian Ocean in a simulation with emissions from the fires relative to a simulation without the emissions. Another important export pathway was to the tropical and subtropical South Pacific Ocean in the southern subtropical jet. A more episodic pathway occurred to the tropics and subtropics of the North Pacific Ocean. By December, the tropospheric CO column from the fires had mixed zonally and somewhat symmetrically about the equator impacting both the Northern and Southern Hemisphere similarly. The model's CO column was elevated by 10-20% from 30degreesN to 45degreesS in December, by 5-10% poleward of 45degreesS, and by less than 5% poleward of 45degreesN. The relative impact of the fires was lower in the Northern Hemisphere, as the background CO column is typically higher there. The fires decreased the concentration of the hydroxyl radical (OH) in the model by more than 20% over much of the tropical Indian Ocean through consumption by CO, heterogeneous loss of odd-oxygen radicals (HOx) on black (BC) and organic carbon (OC) aerosols, and reduction of UV light by the aerosols. The net direct, shortwave radiative forcing at the top of the atmosphere of OC and BC aerosols from the fires was relatively small, as their forcings were similar, but of opposite signs. The net forcing at the surface, however, was large, about -10 W m(-2) over most of the tropical Indian Ocean and as low as -150 W m(-2) over the burning regions in Indonesia, indicating that aerosols from the fires significantly perturbed the tropical radiative budget. The calculated forcing of O3 was minor relative to those of BC and OC aerosols. C1 Ecole Polytech Fed Lausanne, Lab Modelisat Chim Atmospher, CH-1015 Lausanne, Switzerland. Georgia Inst Technol, Sch Earth & Atmospher Sci, Atlanta, GA 30332 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 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, Chem & Dynam Branch, Hampton, VA 23665 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Meteorol Res Inst, Geochem Res Dept, Tsukuba, Ibaraki 3050052, Japan. RP Duncan, BN (reprint author), Ecole Polytech Fed Lausanne, Lab Modelisat Chim Atmospher, CH-1015 Lausanne, Switzerland. EM bryan.duncan@epfl.ch; isabelle.bey@epfl.ch; chin@rondo.gsfc.nasa.gov; ljm@io.harvard.edu; tdf@io.harvard.edu; rvmartin@fas.harvard.edu; hmatsued@mri-jma.go.jp RI Martin, Randall/A-2051-2008; Duncan, Bryan/A-5962-2011; Chin, Mian/J-8354-2012; Mickley, Loretta/D-2021-2012; Martin, Randall/C-1205-2014; Chem, GEOS/C-5595-2014 OI Mickley, Loretta/0000-0002-7859-3470; Martin, Randall/0000-0003-2632-8402; NR 123 TC 79 Z9 80 U1 0 U2 19 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 AUG 7 PY 2003 VL 108 IS D15 AR 4458 DI 10.1029/2002JD003195 PG 25 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 712PK UT WOS:000184805900004 ER PT J AU Lary, DJ Khattatov, B Mussa, HY AF Lary, DJ Khattatov, B Mussa, HY TI Chemical data assimilation: A case study of solar occultation data from the ATLAS 1 mission of the Atmospheric Trace Molecule Spectroscopy Experiment (ATMOS) SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE data assimilation; chemical Kalman filter; skill scores; ATMOS; ozone assimilation ID VARIATIONAL DATA ASSIMILATION; CHEMISTRY-TRANSPORT MODEL; RADIATION-FIELD; POTENTIAL VORTICITY; DIFFUSE-RADIATION; ER-2 AIRCRAFT; KALMAN FILTER; POLAR VORTEX; GAS BUDGETS; STRATOSPHERE AB A key advantage of using data assimilation is the propagation of information from data-rich regions to data-poor regions, which is particularly relevant to the use of solar occultation data such as from the Atmospheric Trace Molecule Spectroscopy Experiment (ATMOS). For the first time, an in-depth uncertainty analysis is included in a photochemical model-data intercomparison including observation, representativeness, and theoretical uncertainty. Chemical data assimilation of solar occultation measurements can be used to reconstruct full diurnal cycles and to evaluate their chemical self-consistency. This paper considers as an example the measurements made by the ATMOS instrument ATLAS 1 during March 1992 for a vertical profile in flow-tracking coordinates at an equivalent potential vorticity (PV) latitude of 38degreesS. ATMOS was chosen because it simultaneously observes several species. This equivalent PV latitude was chosen as it was where ATMOS observed the atmosphere's composition over the largest range of altitudes. A single vertical profile was used so that the detailed diurnal information that the assimilation utilizes could be highlighted. There is generally good self-consistency between the ATMOS ATLAS 1 observations of O-3, NO, NO2, N2O5, HNO3, HO2NO2, HCN, ClONO2, HCl, H2O, CO, CO2, CH4, and N2O and between the observations and photochemical theory. C1 NASA, Goddard Space Flight Ctr, Data Assimilat Off, Greenbelt, MD 20771 USA. Natl Ctr Atmospher Res, Boulder, CO 80307 USA. Univ Cambridge, Unilever Cambridge Ctr, Atmospher Res Ctr, Cambridge CB2 1EW, England. RP Lary, DJ (reprint author), NASA, Goddard Space Flight Ctr, Data Assimilat Off, Code 910-3, Greenbelt, MD 20771 USA. EM dlary@dao.gsfc.nasa.gov; boris@ucar.edu; hym21@cam.ac.uk RI Lary, David/A-6163-2010 NR 53 TC 3 Z9 3 U1 0 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 AUG 7 PY 2003 VL 108 IS D15 AR 4456 DI 10.1029/2003JD003500 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 712PK UT WOS:000184805900006 ER PT J AU Reid, JS Kinney, JE Westphal, DL Holben, BN Welton, EJ Tsay, SC Eleuterio, DP Campbell, JR Christopher, SA Colarco, PR Jonsson, HH Livingston, JM Maring, HB Meier, ML Pilewskie, P Prospero, JM Reid, EA Remer, LA Russell, PB Savoie, DL Smirnov, A Tanre, D AF Reid, JS Kinney, JE Westphal, DL Holben, BN Welton, EJ Tsay, SC Eleuterio, DP Campbell, JR Christopher, SA Colarco, PR Jonsson, HH Livingston, JM Maring, HB Meier, ML Pilewskie, P Prospero, JM Reid, EA Remer, LA Russell, PB Savoie, DL Smirnov, A Tanre, D TI Analysis of measurements of Saharan dust by airborne and ground-based remote sensing methods during the Puerto Rico Dust Experiment (PRIDE) SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE dust; aerosol; meteorology; Sahara; vertical distribution; Caribbean ID AEROSOL-SIZE DISTRIBUTION; LONG-RANGE TRANSPORT; MINERAL DUST; OPTICAL-PROPERTIES; EASTERLY WAVES; ATMOSPHERIC TRANSPORT; ATLANTIC-OCEAN; UNITED-STATES; DRY YEARS; LIDAR AB For 26 days in mid-June and July 2000, a research group comprised of U. S. Navy, NASA, and university scientists conducted the Puerto Rico Dust Experiment (PRIDE). In this paper we give a brief overview of mean meteorological conditions during the study. We focus on our findings on African dust transported into the Caribbean utilizing a Navajo aircraft and AERONET Sun photometer data. During the study midvisible aerosol optical thickness (AOT) in Puerto Rico averaged 0.25, with a maximum >0.5 and with clean marine periods of similar to0.08. Dust AOTs near the coast of Africa (Cape Verde Islands and Dakar) averaged similar to0.4, 30% less than previous years. By analyzing dust vertical profiles in addition to supplemental meteorology and MPLNET lidar data we found that dust transport cannot be easily categorized into any particular conceptual model. Toward the end of the study period, the vertical distribution of dust was similar to the commonly assumed Saharan Air Layer (SAL) transport. During the early periods of the study, dust had the highest concentrations in the marine and convective boundary layers with only a weak dust layer in the SAL being present, a state usually associated with wintertime transport patterns. We corroborate the findings of Maring et al. [2003] that in most cases, there was an unexpected lack of vertical stratification of dust particle size. We systematically analyze processes that may impact dust vertical distribution and speculate that dust vertical distribution predominately influenced by flow patterns over Africa and differential advection coupled with fair weather cloud entrainment, mixing by easterly waves, and regional subsidence. C1 Space & Naval Warfare Syst Ctr San Diego, San Diego, CA 92152 USA. USN, Res Lab, Monterey, CA 93943 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. USN, Postgrad Sch, Monterey, CA 93943 USA. Sci Syst & Applicat Inc, Greenbelt, MD 20771 USA. Univ Maryland Baltimore Cty, Baltimore, MD 21250 USA. Univ Alabama, Dept Atmospher Sci, Huntsville, AL 35805 USA. Univ Colorado, Program Atmospher & Ocean Sci, Atmospher & Space Phys Lab, Boulder, CO 80309 USA. SRI Int, Menlo Pk, CA 94025 USA. Univ Miami, Rosenstiel Sch Marine & Atmospher Sci, Miami, FL 33149 USA. Univ Calif Davis, Davis, CA 95616 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ Sci & Technol Lille, CNRS, Opt Atmospher Lab, F-59655 Villeneuve Dascq, France. RP Reid, JS (reprint author), Space & Naval Warfare Syst Ctr San Diego, 53560 Hull St, San Diego, CA 92152 USA. EM reidj@nrlmry.navy.mil RI Smirnov, Alexander/C-2121-2009; Christopher, Sundar/E-6781-2011; Welton, Ellsworth/A-8362-2012; Campbell, James/C-4884-2012; Reid, Jeffrey/B-7633-2014; Tsay, Si-Chee/J-1147-2014; Colarco, Peter/D-8637-2012 OI Smirnov, Alexander/0000-0002-8208-1304; Campbell, James/0000-0003-0251-4550; Reid, Jeffrey/0000-0002-5147-7955; Colarco, Peter/0000-0003-3525-1662 NR 53 TC 84 Z9 83 U1 1 U2 15 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 AUG 7 PY 2003 VL 108 IS D19 AR 8586 DI 10.1029/2002JD002493 PG 27 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 712XY UT WOS:000184825900001 ER PT J AU Santee, ML Manney, GL Waters, JW Livesey, NJ AF Santee, ML Manney, GL Waters, JW Livesey, NJ TI Variations and climatology of ClO in the polar lower stratosphere from UARS Microwave Limb Sounder measurements SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE Microwave Limb Sounder (MLS); Upper Atmosphere Research Satellite (UARS); chlorine activation; chlorine monoxide (ClO); stratospheric chemistry; polar processing ID ATMOSPHERE RESEARCH SATELLITE; MILLIMETER-WAVE MEASUREMENTS; GROUND-BASED MEASUREMENTS; ANTARCTIC SPRING VORTEX; MIDLATITUDE OZONE LOSS; CHLORINE MONOXIDE; ARCTIC WINTER; HETEROGENEOUS CHEMISTRY; MLS OBSERVATIONS; MCMURDO-STATION AB The Microwave Limb Sounder (MLS) on board the Upper Atmosphere Research Satellite (UARS) measured the global distribution of stratospheric ClO over annual cycles for much of the 1990s, albeit with reduced sampling frequency in the latter half of the decade. Here we present an overview of the interannual and interhemispheric variations in the distribution of ClO derived from UARS MLS measurements, with a particular emphasis on enhancements in the winter polar lower stratosphere. Although ClO enhancement within the Arctic vortex is comparable in both magnitude and spatial extent to that in the Antarctic at 465 K (similar to19 km), a significant interhemispheric disparity is seen at higher altitudes, where maximum ClO abundances, and their spatial extent, are considerably larger in the Antarctic than in the Arctic. The Arctic exhibits much more interannual variability in the magnitude, timing, and distribution of ClO enhancement than does the Antarctic. Nevertheless, during the mid-1990s, when the Arctic lower stratosphere was atypically cold, MLS observed the Arctic vortex to be almost completely filled with enhanced ClO in midwinter to late winter. The peak in the ClO profile is at a higher altitude, and the vertical extent of chlorine activation is larger, in the Antarctic than in the Arctic. The Arctic winter of 1995/1996, however, stands out as having a much more Antarctic-like ClO distribution, with larger maximum ClO abundances, a higher altitude for the profile peak, and greater horizontal and vertical extent of activation than the other winters observed by UARS MLS. In the Southern Hemisphere, ClO becomes enhanced in the sunlit portions of the vortex by at least late May/early June every year, whereas in the Northern Hemisphere, ClO becomes enhanced in mid to late December in some years but not until January in others. Elevated levels of reactive chlorine persist for 4-5 months in the south but only 2-3 months in the north. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. New Mexico Highlands Univ, Dept Nat Sci, Las Vegas, NM 87701 USA. RP Santee, ML (reprint author), CALTECH, Jet Prop Lab, Mail Stop 183-701,4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM mls@mls.jpl.nasa.gov; manney@mls.jpl.nasa.gov; joe@mls.jpl.nasa.gov; livesey@mls.jpl.nasa.gov NR 77 TC 26 Z9 26 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 AUG 7 PY 2003 VL 108 IS D15 AR 4454 DI 10.1029/2002JD003335 PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 712PK UT WOS:000184805900005 ER PT J AU Gross, RS Fukumori, I Menemenlis, D AF Gross, RS Fukumori, I Menemenlis, D TI Atmospheric and oceanic excitation of the Earth's wobbles during 1980-2000 SO JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH LA English DT Article DE Earth rotation; polar motion; atmospheric angular momentum; oceanic angular momentum; Chandler wobble ID POLAR MOTION EXCITATION; SHORT PERIODIC VARIATIONS; BASE-LINE INTERFEROMETRY; ANGULAR-MOMENTUM; GRAVITATIONAL-FIELD; CHANDLER-WOBBLE; SEA-LEVEL; ROTATION; MODEL; ORIENTATION AB Because of the action of various geophysical excitation mechanisms, the Earth does not rotate about its figure axis, so it wobbles as it rotates. Here, the effectiveness of atmospheric and oceanic processes in exciting the Earth's wobbles during 1980-2000 is evaluated using estimates of atmospheric angular momentum from the National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) reanalysis project and estimates of oceanic angular momentum from the Estimating the Circulation and Climate of the Ocean (ECCO) consortium's simulation of the general circulation of the oceans. On intraseasonal timescales, atmospheric surface pressure changes are found to be the single most effective process exciting the Earth's wobbles, explaining about twice as much of the observed variance as do either atmospheric wind or ocean bottom pressure changes and nearly 4 times as much of the observed variance as do oceanic currents. However, on interannual timescales, ocean bottom pressure changes are found to be the single most effective process exciting the Earth's wobbles, explaining more than 5 times as much of the observed variance as do atmospheric wind and pressure changes combined, and more than twice as much of the observed variance as do oceanic currents. Within the Chandler band it is found that during 1980-2000 atmospheric and oceanic processes have enough power to excite the Chandler wobble and are significantly coherent with it. The single most important mechanism exciting the Chandler wobble is found to be ocean bottom pressure variations. Atmospheric and oceanic processes do not appear to have enough power to excite the Earth's wobbles to their observed levels on pentadal and longer timescales, although series longer than the 21-year long series used here need to be studied in order to obtain greater statistical significance of this result. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM richard.gross@jpl.nasa.gov NR 72 TC 79 Z9 81 U1 1 U2 9 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 AUG 7 PY 2003 VL 108 IS B8 AR 2370 DI 10.1029/2002JB002143 PG 16 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 712YJ UT WOS:000184826900004 ER PT J AU Hodis, HN Mack, WJ Azen, SP Lobo, RA Shoupe, D Mahrer, PR Faxon, DP Cashin-Hemphill, L Sanmarco, ME French, WJ Shook, TL Gaarder, TD Mehra, AO Rabbani, R Sevanian, A Shil, AB Torres, M Vogelbach, KH Selzer, RH Hodis, HN Azen, SP Faxon, DP Lobo, RA Mack, WJ Charlson, M Gesselman, C Morales, T Torres, M Watcher, F Zurbrugg, L Faxon, DP Mehra, AO Rabbani, R Agra, B Coria, I Ee, J Johnson, S Reyes, L Stolicky, C Mahrer, PR Aharonian, VJ Browning, RA Jackimowicz, P Scutella, PJ Velasco, A Williams, C French, WJ Shook, TL Matthews, RV Vogelbach, KH Ujiiye, DL Selzer, RH Shil, AB Shircore, A Mack, WJ Azen, SP Ying-Lai, M Morales, O Xiang, M Sevanian, A Hwang, J Bolusan, O Ramirez, A Cashin-Hemphill, L Sanmarco, ME Faxon, DP French, WJ Gaarder, TD Mahrer, PR Mehra, AO Rabbani, R Shook, TL Mezrow, G Shoupe, D Stanczyk, FZ Felix, JC Parisky, Y Brown, BG Chaudhuri, G Malloy, M Odom-Maryon, T Wilson-Ross, J Gordon, DJ AF Hodis, HN Mack, WJ Azen, SP Lobo, RA Shoupe, D Mahrer, PR Faxon, DP Cashin-Hemphill, L Sanmarco, ME French, WJ Shook, TL Gaarder, TD Mehra, AO Rabbani, R Sevanian, A Shil, AB Torres, M Vogelbach, KH Selzer, RH Hodis, HN Azen, SP Faxon, DP Lobo, RA Mack, WJ Charlson, M Gesselman, C Morales, T Torres, M Watcher, F Zurbrugg, L Faxon, DP Mehra, AO Rabbani, R Agra, B Coria, I Ee, J Johnson, S Reyes, L Stolicky, C Mahrer, PR Aharonian, VJ Browning, RA Jackimowicz, P Scutella, PJ Velasco, A Williams, C French, WJ Shook, TL Matthews, RV Vogelbach, KH Ujiiye, DL Selzer, RH Shil, AB Shircore, A Mack, WJ Azen, SP Ying-Lai, M Morales, O Xiang, M Sevanian, A Hwang, J Bolusan, O Ramirez, A Cashin-Hemphill, L Sanmarco, ME Faxon, DP French, WJ Gaarder, TD Mahrer, PR Mehra, AO Rabbani, R Shook, TL Mezrow, G Shoupe, D Stanczyk, FZ Felix, JC Parisky, Y Brown, BG Chaudhuri, G Malloy, M Odom-Maryon, T Wilson-Ross, J Gordon, DJ CA WELL-HART Res Grp TI Hormone therapy and the progression of coronary-artery atherosclerosis in postmenopausal women SO NEW ENGLAND JOURNAL OF MEDICINE LA English DT Article ID ESTROGEN PLUS PROGESTIN; CONJUGATED EQUINE ESTROGENS; RANDOMIZED CONTROLLED TRIAL; COLESTIPOL-NIACIN THERAPY; HEART-DISEASE; REPLACEMENT THERAPY; CLINICAL-TRIALS; PREVENTION; REGRESSION; RECEPTOR AB BACKGROUND: In postmenopausal women with coronary artery disease, conjugated equine estrogen with or without continuous administration of medroxyprogesterone acetate has failed to slow the progression of atherosclerosis. Whether 17(beta)-estradiol (the endogenous estrogen molecule) alone or administered sequentially with medroxyprogesterone acetate can slow the progression of atherosclerosis is unknown. METHODS: We conducted a double-blind, placebo-controlled trial in 226 postmenopausal women (mean age, 63.5 years) who had at least one coronary-artery lesion. Participants were randomly assigned to usual care (control group), estrogen therapy with micronized 17(beta)-estradiol alone (estrogen group), or 17(beta)-estradiol plus sequentially administered medroxyprogesterone acetate (estrogen-progestin group). In all patients the low-density lipoprotein (LDL) cholesterol level was reduced to a target of less than 130 mg per deciliter. The primary outcome was the average per-participant change between base-line and follow-up coronary angiograms in the percent stenosis measured by quantitative coronary angiography. RESULTS: After a median of 3.3 years of follow-up, the mean (+/-SE) change in the percent stenosis in the 169 participants who had a pair of matched angiograms was 1.89+/-0.78 percentage points in the control group, 2.18+/-0.76 in the estrogen group, and 1.24+/-0.80 in the estrogen-progestin group (P=0.66 for the comparison among the three groups). The mean difference in the percent stenosis between the estrogen group and the control group was 0.29 percentage point (95 percent confidence interval, -1.88 to 2.46), and the mean difference between the estrogen-progestin group and the control group was -0.65 (95 percent confidence interval, -2.87 to 1.57). CONCLUSIONS: In older postmenopausal women with established coronary-artery atherosclerosis, 17(beta)-estradiol either alone or with sequentially administered medroxyprogesterone acetate had no significant effect on the progression of atherosclerosis. C1 Univ So Calif, Keck Sch Med, Atherosclerosis Res Unit, Los Angeles, CA 90033 USA. Univ So Calif, Dept Prevent Med, Los Angeles, CA 90033 USA. Univ So Calif, Dept Mol Pharmacol & Toxicol, Sch Pharm, Los Angeles, CA 90033 USA. Univ So Calif, Dept Obstet & Gynecol, Los Angeles, CA 90033 USA. Univ So Calif, Div Cardiovasc Med, Los Angeles, CA 90033 USA. Columbia Univ Coll Phys & Surg, Dept Obstet & Gynecol, New York, NY 10032 USA. Kaiser Permanente Med Ctr, Los Angeles, CA 90034 USA. Univ Chicago, Div Cardiol, Chicago, IL USA. Boston Heart Fdn, Boston, MA USA. Lakewood Reg Med Ctr, Lakewood, CA USA. Univ Calif Los Angeles, Harbor Med Ctr, Div Cardiol, Torrance, CA 90509 USA. Good Samaritan Hosp, Los Angeles, CA USA. Presbyterian Intercommunity Hosp, Whittier, CA USA. So Calif Heart Specialits, Pasadena, CA USA. CALTECH, Jet Prop Lab, Pasadena, CA USA. RP Hodis, HN (reprint author), Univ So Calif, Keck Sch Med, Atherosclerosis Res Unit, 2250 Alcazar St,CSC132, Los Angeles, CA 90033 USA. FU NHLBI NIH HHS [U01-HL-49298] NR 40 TC 225 Z9 231 U1 0 U2 6 PU MASSACHUSETTS MEDICAL SOC/NEJM PI WALTHAM PA WALTHAM WOODS CENTER, 860 WINTER ST,, WALTHAM, MA 02451-1413 USA SN 0028-4793 J9 NEW ENGL J MED JI N. Engl. J. Med. PD AUG 7 PY 2003 VL 349 IS 6 BP 535 EP 545 DI 10.1056/NEJMoa030830 PG 11 WC Medicine, General & Internal SC General & Internal Medicine GA 708JL UT WOS:000184563500004 PM 12904518 ER PT J AU Poli, P Ao, CO Juarez, MD Joiner, J Hajj, GA Hoff, RM AF Poli, P Ao, CO Juarez, MD Joiner, J Hajj, GA Hoff, RM TI Evaluation of CHAMP radio occultation refractivity using data assimilation office analyses and radiosondes SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID ATMOSPHERE AB [1] The radio occultation experiment on the CHAMP satellite has been collecting observations of the Earth's atmosphere since April 2001. Previous work has shown that diffraction effects not accounted for by geometrical optics processing can be partially corrected by back-propagation and canonical transform methods, such as implemented at the Jet Propulsion Laboratory. In the present paper we evaluate the bias and standard deviation of refractivity differences between Data Assimilation Office global analyses and observations processed by these three methods. In the tropics at 2 - 5 km altitude, the refractivity biases range between -2.5% and -0.5% for geometrical optics, between -1% and 0.5% for back-propagation, and between -0.5% and 1.5% for canonical transform. We also assess the methods by performing one-dimensional variational temperature retrievals and comparing them with close radiosondes. Our final conclusion is that canonical transform is a better candidate than geometrical optics and back-propagation for generating GPS radio occultation datasets for data assimilation. C1 NASA, Data Assimilat Off, Goddard Space Flight Ctr, Greenbelt, MD 20770 USA. Univ Maryland Baltimore Cty, Joint Ctr Earth Syst Technol, Baltimore, MD 21250 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Meteo France, Ctr Natl Rech Meteorol, Toulouse, France. RP Poli, P (reprint author), NASA, Data Assimilat Off, Goddard Space Flight Ctr, Mailcode 910-3, Greenbelt, MD 20770 USA. RI Hoff, Raymond/C-6747-2012; Joiner, Joanna/D-6264-2012; OI Poli, Paul/0000-0002-8392-6524 NR 12 TC 6 Z9 7 U1 2 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 AUG 6 PY 2003 VL 30 IS 15 AR 1800 DI 10.1029/2003GL017637 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 712NX UT WOS:000184804700003 ER PT J AU Colarco, PR Toon, OB Reid, JS Livingston, JM Russell, PB Redemann, J Schmid, B Maring, HB Savoie, D Welton, EJ Campbell, JR Holben, BN Levy, R AF Colarco, PR Toon, OB Reid, JS Livingston, JM Russell, PB Redemann, J Schmid, B Maring, HB Savoie, D Welton, EJ Campbell, JR Holben, BN Levy, R TI Saharan dust transport to the Caribbean during PRIDE: 2. Transport, vertical profiles, and deposition in simulations of in situ and remote sensing observations SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE dust aerosols; long-range transport; vertical profiles; deposition; wet removal; iron fluxes ID MINERAL DUST; ATMOSPHERIC TRANSPORT; AEROSOL PROPERTIES; MODEL; AERONET; LIDAR; DISTRIBUTIONS; RADIATION; PARTICLES; ATLANTIC AB [ 1] We simulate Saharan dust transport during the Puerto Rico Dust Experiment ( June July 2000) with a three-dimensional aerosol transport model driven by assimilated meteorology. The model does a reasonable job of locating the dust plume as it emerges from Africa but transports it somewhat farther south in the western North Atlantic Ocean than is seen in satellite imagery. The model is able to simulate low-level, uniformly mixed, and elevated vertical dust layer profiles over Puerto Rico similar to observations made in PRIDE. We determine that the variability in the dust vertical profile across the North Atlantic Ocean is most strongly associated with descent of the dust by sedimentation and downward vertical winds during transit rather than low-level transport directly from source regions. Wet removal plays a key role in modulating this process. Assuming our dust is 3.5% iron by mass, we estimate July 2000 iron deposition into the North Atlantic Ocean to be between 0.71 and 0.88 Tg, which is consistent with estimates derived from observed surface dust mass concentrations. We estimate that if annual dust deposition remains constant at five times our July 2000 estimates, there is an accumulation of 1 m of sediment from Saharan dust over the Florida peninsula every one million years. C1 Univ Colorado, Atmospher & Space Phys Lab, Program Atomospher & Ocean Sci, Boulder, CO 80309 USA. USN, Res Lab, Marine Meteorol Div, Monterey, CA 93943 USA. SRI Int, Menlo Pk, CA 94025 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Bay Area Environm Res Inst, Sonoma, CA 95476 USA. Univ Miami, Rosenstiel Sch Marine & Atmospher Sci, Miami, FL 33149 USA. Univ Maryland Baltimore Cty, NASA, Goddard Space Flight Ctr, Goddard Earth Sci & Technol Ctr, Greenbelt, MD 20771 USA. Sci Syst & Applicat Inc, Lanham, MD 20706 USA. NASA, Goddard Space Flight Ctr, Terr Phys Lab, Greenbelt, MD 20771 USA. RP NASA, Goddard Space Flight Ctr, Goddard Earth Sci & Technol Ctr, Greenbelt, MD 20771 USA. EM peter.colarco@gsfc.nasa.gov RI Welton, Ellsworth/A-8362-2012; Campbell, James/C-4884-2012; Colarco, Peter/D-8637-2012; Levy, Robert/M-7764-2013; Reid, Jeffrey/B-7633-2014 OI Campbell, James/0000-0003-0251-4550; Colarco, Peter/0000-0003-3525-1662; Levy, Robert/0000-0002-8933-5303; Reid, Jeffrey/0000-0002-5147-7955 NR 35 TC 73 Z9 72 U1 0 U2 4 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 AUG 6 PY 2003 VL 108 IS D19 AR 8590 DI 10.1029/2002JD002659 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 712XX UT WOS:000184825800001 ER PT J AU Yuan, DL Rienecker, MM AF Yuan, DL Rienecker, MM TI Inverse estimation of sea surface heat flux over the equatorial Pacific Ocean: Seasonal cycle SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article DE surface; heat; flux; temperature; equator; Pacific ID TROPICAL PACIFIC; EL-NINO; SOUTHERN OSCILLATION; MODEL SIMULATION; MIXED-LAYER; TEMPERATURE; BALANCE; CLIMATOLOGY; CIRCULATION; VARIABILITY AB [ 1] An assimilation of satellite-derived sea surface temperature (SST) observations into the Poseidon quasi-isopycnal ocean model is conducted to study the seasonal cycle of surface thermodynamics of the equatorial Pacific Ocean and to estimate the sea surface heat flux inversely from the SST observations. A simplified approach in the use of the thermodynamic submodel that separates the momentum and the temperature fields in the variational assimilation procedure proves successful in improving the model simulation of the observed SST. From a comparison with several existing bulk estimates, it is seen that the seasonal cycle of sea surface heat flux has been captured well by the inversion except in the eastern equatorial Pacific, where the optimized surface heat flux shows an upward flux during the boreal summer/fall season when the cold tongue SST starts to decrease dramatically. This spurious upward surface heat flux is inconsistent with the bulk estimates and is determined to be due to model deficiencies in calculating vertical turbulent diffusion. The SST data assimilation is shown to have improved the model simulation of horizontal temperature advection significantly. A comparison of the inferred heat budget is made with an analysis by Wang and McPhaden [1999] from TAO mooring observations. C1 NASA, Lab Hydrospher Proc, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Maryland Baltimore Cty, Goddard Earth Sci & Technol Ctr, Baltimore, MD 21228 USA. EER Syst Inc, Chantilly, VA USA. RP Yuan, DL (reprint author), NASA, Distributed Act Archive Ctr, Goddard Space Flight Ctr, Code 661, Greenbelt, MD 20771 USA. NR 49 TC 6 Z9 6 U1 3 U2 3 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 AUG 5 PY 2003 VL 108 IS C8 AR 3247 DI 10.1029/2002JC001367 PG 14 WC Oceanography SC Oceanography GA 712YA UT WOS:000184826100001 ER PT J AU Chang, SW Scudder, JD Kudela, K Spence, HE Fennell, JF Lepping, RP Lin, RP Russell, CT AF Chang, SW Scudder, JD Kudela, K Spence, HE Fennell, JF Lepping, RP Lin, RP Russell, CT TI Reply to comment on ''MeV magnetosheath ions energized at the bow shock'' by J. Chen, T. A. Fritz, and R. B. Sheldon SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Editorial Material DE bow shock acceleration; magnetosheath energetic particle; Fermi acceleration ID CUSP ENERGETIC IONS; ULF POWER SPECTRA; MEV HELIUM; UPSTREAM; MAGNETOSPHERE; EVENTS C1 Univ Alabama, Ctr Space Plasma & Aeron Res, Huntsville, AL 35899 USA. NASA, George C Marshall Space Flight Ctr, Dept Space Sci, Huntsville, AL 35812 USA. Univ Iowa, Dept Phys & Astron, Iowa City, IA 52242 USA. Slovak Acad Sci, Inst Expt Phys, Kosice 04353, Slovakia. Boston Univ, Dept Astron & Space Sci, Ctr Space Phys, Boston, MA 02215 USA. Aerosp Corp, Los Angeles, CA 90009 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. Univ Calif Los Angeles, Inst Geophys & Planetary Phys, Los Angeles, CA 90095 USA. RP Chang, SW (reprint author), Natl Space Sci & Technol Ctr, SD50,320 Sparkman Dr, Huntsville, AL 35805 USA. RI Scudder, Jack/D-8417-2013; Spence, Harlan/A-1942-2011; OI Scudder, Jack/0000-0001-7975-5630; Spence, Harlan/0000-0002-2526-2205 NR 13 TC 4 Z9 4 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 AUG 5 PY 2003 VL 108 IS A8 AR 1312 DI 10.1029/2002JA009724 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 712YL UT WOS:000184827100002 ER PT J AU Norvig, P AF Norvig, P TI PowerPoint: shot with its own bullets SO LANCET LA English DT Editorial Material C1 NASA, Washington, DC 20546 USA. NR 5 TC 9 Z9 9 U1 0 U2 0 PU LANCET LTD PI LONDON PA 84 THEOBALDS RD, LONDON WC1X 8RR, ENGLAND SN 0140-6736 J9 LANCET JI Lancet PD AUG 2 PY 2003 VL 362 IS 9381 BP 343 EP 344 DI 10.1016/S0140-6736(03)14056-1 PG 2 WC Medicine, General & Internal SC General & Internal Medicine GA 707FB UT WOS:000184498700005 PM 12907004 ER PT J AU Ziv, A Wolpe, PR Small, SD Glick, S AF Ziv, A Wolpe, PR Small, SD Glick, S TI Simulation-based medical education: An ethical imperative SO ACADEMIC MEDICINE LA English DT Article ID CLINICAL COMPETENCE; ROLE-PLAY; ERRORS; CONSENT; SKILLS; CONSULTATION; MANAGEMENT; SYSTEM; OSCE AB Medical training must at some point use live patients to hone the skills of health professionals. But there is also an obligation to provide optimal treatment and to ensure patients' safety and well-being. Balancing these two needs represents a fundamental ethical tension in medical education. Simulation-based learning can help mitigate this tension by developing health professionals' knowledge, skills, and attitudes while protecting patients from unnecessary risk. Simulation-based training has been institutionalized in other high-hazard professions, such as aviation, nuclear power, and the military, to maximize training safety and minimize risk. Health care has lagged behind in simulation applications for a number of reasons, including cost, lack of rigorous proof of effect, and resistance to change. Recently, the international patient safety movement and the U.S. federal policy agenda have created a receptive atmosphere for expanding the use of simulators in medical training, stressing the ethical imperative to "first do no harm" in the face of validated, large epidemiological studies describing unacceptable preventable injuries to patients as a result of medical management. Four themes provide a framework for an ethical analysis of simulation-based medical education: best standards of care and training, error management and patient safety, patient autonomy, and social justice and resource allocation. These themes are examined from the perspectives of patients, learners, educators, and society. The use of simulation wherever feasible conveys a critical educational and ethical message to all: patients are to be protected whenever possible and they are not commodities to be used as conveniences of training. C1 Chaim Sheba Med Ctr, IL-52621 Tel Hashomer, Israel. Israel Ctr Med Simulat MSR, Tel Hashomer, Israel. Univ Penn, Dept Psychiat, Ctr Bioeth, Philadelphia, PA 19104 USA. Univ Penn, Dept Sociol, Ctr Bioeth, Philadelphia, PA 19104 USA. NASA, Washington, DC 20546 USA. Univ Chicago, Dev Ctr Patient Safety, Dept Anesthesiol & Crit Care, Chicago, IL 60637 USA. Ben Gurion Univ Negev, Moshe Prywes Ctr Med Educ, Immanuel Jakobovitis Ctr Jewish Med Eth, IL-84105 Beer Sheva, Israel. RP Small, SD (reprint author), Univ Chicago, Med Ctr, Dept Anesthesia & Crit Care, Dev Ctr Patient Safety, 5841 S Maryland Ave,MC 4028, Chicago, IL 60637 USA. EM ssmall@airway.uchicago.edu RI Wolpe, Paul/A-1032-2007 FU AHRQ HHS [P20 HS 11553, U18 HS 11905] NR 54 TC 299 Z9 314 U1 7 U2 43 PU ASSOC AMER MEDICAL COLLEGES PI WASHINGTON PA 2450 N ST N W, WASHINGTON, DC 20037-1126 USA SN 1040-2446 J9 ACAD MED JI Acad. Med. PD AUG PY 2003 VL 78 IS 8 BP 783 EP 788 DI 10.1097/00001888-200308000-00006 PG 6 WC Education, Scientific Disciplines; Health Care Sciences & Services SC Education & Educational Research; Health Care Sciences & Services GA 801BD UT WOS:000220070500006 PM 12915366 ER PT J AU Bushnell, GS Fialho, IJ McDavid, T Allen, JL Quraishi, N AF Bushnell, GS Fialho, IJ McDavid, T Allen, JL Quraishi, N TI Ground and on-orbit command and data handling architectures for the Active Rack Isolation System microgravity flight experiment SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT 53rd Congress of the International-Astronautical-Federation (IAF) CY OCT 10, 2002 CL HOUSTON, TEXAS SP Internat Astronaut Fed (IAF) AB The Active Rack Isolation System [ARIS] International Space Station [ISS] Characterization Experiment, or ARIS-ICE for short, is a long duration microgravity characterization experiment aboard the ISS. The objective of the experiment is to fully characterize active microgravity performance of the first ARIS rack deployed on the ISS. Efficient ground and on-orbit command and data handling [C&DH] segments are the crux in achieving the challenging objectives of the mission. The objective of the paper is to provide an overview of the C&DH architectures developed for ARIS-ICE, with the view that these architectures may serve as a model for future ISS microgravity payloads. Both ground and on-orbit segments, and their interaction with corresponding ISS C&DH systems are presented. The heart of the on-orbit segment is the ARIS-ICE Payload On-orbit Processor, ARIS-ICE POP for short. The POP manages communication with the ISS C&DH system and other ISS subsystems and payloads, enables automation of test/data collection sequences, and provides a wide range of utilities such as efficient file downlinks/uplinks, data post-processing, data compression and data storage. The hardware and software architecture of the POP is presented and it is shown that the built-in functionality helps to dramatically streamline the efficiency of on-orbit operations.-The ground segment has at its heart special ARIS-ICE Ground Support Equipment [GSE] software developed for the experiment. The software enables efficient command and file uplinks, and reconstruction and display of science telemetry packets. The GSE software architecture is discussed along with its interactions with ISS ground C&DH elements. A test sequence example is used to demonstrate the interplay between the ground and on-orbit segments. (C) 2003 Elsevier Science Ltd. All rights reserved. C1 Boeing Co, Houston, TX USA. Boeing Co, Seattle, WA 98124 USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Fialho, IJ (reprint author), Boeing Co, Houston, TX USA. NR 3 TC 2 Z9 3 U1 1 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 AUG-NOV PY 2003 VL 53 IS 4-10 BP 309 EP 316 DI 10.1016/S0094-5765(03)00146-2 PG 8 WC Engineering, Aerospace SC Engineering GA 699XH UT WOS:000184081700009 PM 14649257 ER PT J AU Trinh, EH AF Trinh, EH TI Physical sciences research plans for the International Space Station SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT 53rd Congress of the International-Astronautical-Federation (IAF) CY OCT 10, 2002 CL HOUSTON, TEXAS SP Internat Astronaut Fed (IAF) AB The restructuring of the research capabilities of the International Space Station has forced a reassessment of the Physical Sciences research plans and a re-targeting of the major scientific thrusts. The combination of already selected peer-reviewed flight investigations with the initiation of new research and technology programs will allow the maximization of the ISS scientific and technological potential. Fundamental and applied research will use a combination of ISS-based facilities, ground-based activities, and other experimental platforms to address issues impacting fundamental knowledge, industrial and medical applications on Earth, and the technology required for human space exploration. The current flight investigation research plan shows a large number of principal investigators selected to use the remaining planned research facilities. (C) 2003 American Institute of Aeronautics and Astronautics. Published by Elsevier Science Ltd. All rights reserved. C1 NASA, Phys Sci Res Div, Off Biol & Phys Res, Washington, DC 20546 USA. RP Trinh, EH (reprint author), NASA, Phys Sci Res Div, Off Biol & Phys Res, Washington, DC 20546 USA. 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 0094-5765 J9 ACTA ASTRONAUT JI Acta Astronaut. PD AUG-NOV PY 2003 VL 53 IS 4-10 BP 317 EP 327 DI 10.1016/S0094-5765(03)00147-4 PG 11 WC Engineering, Aerospace SC Engineering GA 699XH UT WOS:000184081700010 PM 14649258 ER PT J AU Theilig, EE Bindschadler, DL Schimmels, KA Vandermey, N AF Theilig, EE Bindschadler, DL Schimmels, KA Vandermey, N TI Project Galileo: Farewell to the major moons of Jupiter SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT 53rd Congress of the International-Astronautical-Federation (IAF) CY OCT 10, 2002 CL HOUSTON, TEXAS SP Internat Astronaut Fed (IAF) ID IO AB After a six-year odyssey, Galileo has completed its survey of the large moons of Jupiter. In the four years since the end of the primary mission, Galileo provided new insights into the fundamental questions concerning Jupiter and its moons and magnetosphere. Longevity, changing orbital geometry, and multiple flybys afforded the opportunity to distinguish intrinsic versus induced magnetic fields on the Galilean moons, to characterize the dusk side of the magnetosphere, to acquire high resolution observations supporting the possibility of subsurface water within Europa, Ganymede, and Callisto, and to monitor the highly dynamic volcanic activity of Io. In January 2002, a final gravity assist placed the spacecraft on a two-orbit trajectory culminating in a Jupiter impact in September 2003. With the successful completion of the Io encounters, plans are being made for the final encounter of the mission. In November 2002, the spacecraft will fly one Jupiter radius above the planet's cloud-tops, sampling the inner magnetosphere and the gossamer rings. The trajectory will take Galileo close enough to Amalthea (a small inner moon) to obtain the first gravity data for this body. Because a radiation dose of 73 krads is expected on this encounter, which will bring the total radiation dose to greater than four times the spacecraft design limits, the command sequence has to account for the possibility of subsystem failure and the loss of spacecraft control after this perijove passage. One of the primary objectives this year has been to place the spacecraft on a trajectory to impact Jupiter on orbit 35. Galileo's discovery of water beneath the frozen surface of Europa raised concerns about forward contamination by inadvertently impacting that moon and resulted in an end of mission requirement to dispose of the spacecraft. A risk assessment of the final two Io encounters was performed to manage the project's ability to meet this requirement. Radiation affected the extended mission through damage to electronic parts in the attitude control subsystem, the computer memory and some science instruments and by causing transient bus reset indications. Software patches and changed operating strategies were implemented to work around most of the radiation effects. Recovery efforts to enhance the robustness of the Solid State Imaging camera paid off in the acquisition of images at both Io 32 and Io 33. Data on spacecraft performance in the harsh jovian environment may be useful to designers of future missions to Jupiter and its moons. (C) 2003 International Astronautical Federation. Published by Elsevier Science Ltd. All rights reserved. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Theilig, EE (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 17 TC 2 Z9 2 U1 0 U2 2 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 AUG-NOV PY 2003 VL 53 IS 4-10 BP 329 EP 352 DI 10.1016/S0094-5765(03)00152-8 PG 24 WC Engineering, Aerospace SC Engineering GA 699XH UT WOS:000184081700011 ER PT J AU Burleigh, S Cerf, V Durst, R Fall, K Hooke, A Scott, K Weiss, H AF Burleigh, S Cerf, V Durst, R Fall, K Hooke, A Scott, K Weiss, H TI The Interplanetary Internet: A communications infrastructure for Mars exploration SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT 53rd Congress of the International-Astronautical-Federation (IAF) CY OCT 10, 2002 CL HOUSTON, TEXAS SP Internat Astronaut Fed (IAF) AB A strategy is being developed whereby the current set of internationally standardized space data communications protocols can be incrementally evolved so that a first version of an operational "Interplanetary Internet" is feasible by the end of the decade. This paper describes it architectural concepts, discusses the current set of standard space data communications capabilities that exist to support Mars exploration and reviews proposed new developments. We also speculate that these current capabilities can grow to support future scenarios where human intelligence is widely distributed across the Solar System and day-to-day communications dialog between planets is routine. (C) 2003 American Institute of Aeronautics and Astronautics. Published by Elsevier Science Ltd. All rights reserved. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. WorldCom Inc, Loudon, VA USA. Mitre Corp, Reston, VA USA. Intel Corp, Berkeley, CA USA. Sparta Syst Inc, Columbia, MD USA. RP Burleigh, S (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 1 TC 4 Z9 6 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 AUG-NOV PY 2003 VL 53 IS 4-10 BP 365 EP 373 DI 10.1016/S0094-5765(03)00154-1 PG 9 WC Engineering, Aerospace SC Engineering GA 699XH UT WOS:000184081700013 PM 14649259 ER PT J AU Cooke, DR Joosten, BK Lo, MW Ford, KM Hansen, RJ AF Cooke, DR Joosten, BK Lo, MW Ford, KM Hansen, RJ TI Innovations in mission architectures for exploration beyond low Earth orbit SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT 53rd Congress of the International-Astronautical-Federation (IAF) CY OCT 10, 2002 CL HOUSTON, TEXAS SP Internat Astronaut Fed (IAF) AB Through the application of advanced technologies and mission concepts, architectures for missions beyond Earth orbit have been dramatically simplified. These concepts enable a stepping stone approach to science driven; technology enabled human and robotic exploration. Numbers and masses of vehicles required are greatly reduced, yet the pursuit of a broader range of science objectives is enabled. The scope of human missions considered range from the assembly and maintenance of large aperture telescopes for emplacement at the Sun-Earth libration point L-2, to human missions to asteroids, the moon and Mars. The vehicle designs are developed for proof of concept, to validate mission approaches and understand the value of new technologies. The stepping stone approach employs an incremental buildup of capabilities, which allows for future decision points on exploration objectives. It enables testing of technologies to achieve greater reliability and understanding of costs for the next steps in exploration. (C) 2003 American Institute of Aeronautics and Astronautics. Published by Elsevier Science Ltd. All rights reserved. C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. NASA, Jet Prop Lab, Pasadena, CA USA. Univ W Florida, Inst Human & Machine Cognit, Pensacola, FL 32514 USA. RP Cooke, DR (reprint author), NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. NR 5 TC 2 Z9 2 U1 0 U2 1 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 AUG-NOV PY 2003 VL 53 IS 4-10 BP 387 EP 397 DI 10.1016/S0094-5765(03)00156-5 PG 11 WC Engineering, Aerospace SC Engineering GA 699XH UT WOS:000184081700015 PM 14649260 ER PT J AU Mazanek, DD Roithmayr, CM Antol, J Kay-Bunnell, L Werner, MR Park, SY Kumar, RR AF Mazanek, DD Roithmayr, CM Antol, J Kay-Bunnell, L Werner, MR Park, SY Kumar, RR TI Comet/Asteroid Protection System (CAPS): A space-based system concept for revolutionizing Earth protection and utilization of near-Earth objects SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT 53rd Congress of the International-Astronautical-Federation (IAF) CY OCT 10, 2002 CL HOUSTON, TEXAS SP Internat Astronaut Fed (IAF) AB There exists an infrequent, but significant hazard to life and property due to impacting asteroids and comets. There is currently no specific search for long-period comets, smaller near-Earth asteroids, or smaller short-period comets. These objects represent a threat with potentially little or no warning time using conventional ground-based telescopes. These planetary bodies also represent a significant resource for commercial exploitation, long-term sustained space exploration, and scientific research. The Comet/Asteroid Protection System (CAPS) would expand the current detection effort to include long-period comets, as well as small asteroids and short-period comets capable of regional destruction. A space-based detection system, despite being more costly and complex than Earth-based initiatives, is the most promising way of expanding the range of detectable objects, and surveying the entire celestial sky on a regular basis. CAPS is a future space-based system concept that provides permanent, continuous asteroid and comet monitoring, and rapid, controlled modification of the orbital trajectories of selected bodies. CAPS would provide an orbit modification system capable of diverting kilometer class objects, and modifying the orbits of smaller asteroids for impact defense and resource utilization. This paper provides a summary of CAPS and discusses several key areas and technologies that are being investigated. (C) 2003 American Institute of Aeronautics and Astronautics. Published by Elsevier Science Ltd. All rights reserved. C1 NASA, Langley Res Ctr, Spacecraft & Sensors, ASCAC, Hampton, VA 23665 USA. George Washington Univ, Joint Inst Advancement Flight Sci, Hampton, VA USA. Swales Aerosp Inc, Hampton, VA USA. Analyt Mech Associates Inc, Hampton, VA USA. RP Mazanek, DD (reprint author), NASA, Langley Res Ctr, Spacecraft & Sensors, ASCAC, Hampton, VA 23665 USA. RI Park, Sang-Young/F-5989-2013 NR 13 TC 1 Z9 1 U1 0 U2 1 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 AUG-NOV PY 2003 VL 53 IS 4-10 BP 405 EP 422 DI 10.1016/S0094-5765(03)00128-0 PG 18 WC Engineering, Aerospace SC Engineering GA 699XH UT WOS:000184081700017 ER PT J AU Torres-Martinez, E Paules, G Schoeberl, M Kalb, MW AF Torres-Martinez, E Paules, G Schoeberl, M Kalb, MW TI A web of sensors: Enabling the Earth Science vision SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT 53rd Congress of the International-Astronautical-Federation (IAF) CY OCT 10, 2002 CL HOUSTON, TEXAS SP Internat Astronaut Fed (IAF) AB Highly coordinated observations and autonomous decision-making are needed to improve our ability to detect, monitor, and predict weather; climate; and the onset of certain natural hazards. The 'SensorWeb' concept has been proposed as a potential solution to this requirement. This paper presents two candidate uses for the concept, describes its capabilities and unique architectural properties, and outlines challenges to overcome for successful development of SensorWeb architectures. The conclusion proposes that the primary challenge to implementation of SensorWebs-beyond the obvious technical obstacles will be our ability to develop and execute a long-term strategy that provides for the deployment of a series of compatible missions that deliver the full promise of envisioned SensorWeb capabilities. Published by Elsevier Science Ltd. C1 NASA, Goddard Space Flight Ctr, Earth Sci Technol Off, Greenbelt, MD 20771 USA. NASA, Earth Sci Enterprise, Washington, DC 20546 USA. NASA, Goddard Space Flight Ctr, Earth Sci Directorate, Greenbelt, MD 20771 USA. Global Sci & Technol Inc, Greenbelt, MD 20770 USA. RP Torres-Martinez, E (reprint author), NASA, Goddard Space Flight Ctr, Earth Sci Technol Off, Greenbelt, MD 20771 USA. NR 6 TC 4 Z9 4 U1 0 U2 2 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 AUG-NOV PY 2003 VL 53 IS 4-10 BP 423 EP 428 DI 10.1016/S0094-5765(03)00133-4 PG 6 WC Engineering, Aerospace SC Engineering GA 699XH UT WOS:000184081700018 ER PT J AU Feingold, H Carrington, C AF Feingold, H Carrington, C TI Evaluation and comparison of space solar power concepts SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT 53rd Congress of the International-Astronautical-Federation (IAF) CY OCT 10, 2002 CL HOUSTON, TEXAS SP Internat Astronaut Fed (IAF) AB The SSP Exploratory Research and Technology (SERT) program undertaken by NASA in the 1999-2000 timeframe was the third in a recent series of NASA sponsored studies of Space Solar Power (SSP) that began with the 1995 SSP "Fresh Look" Study, and was followed by the SSP Concept Definition Study in 1998. In all three studies, a major focus has been on identifying system concepts, architectures and technologies that may ultimately produce a practical, economically viable source of electrical power to help satisfy the world's growing energy needs. As part of the SERT program, members of the study team developed several new and innovative SSP concepts that sprung from a desire to address the problem areas of previous system concepts with new technology and system solutions. In the previous SSP studies it has been shown that systems analyses and sensitivity studies are key to understanding the merits of different system concepts and technologies, particularly with respect to their impact on the mass and cost of space hardware and their ultimate economic impact on the cost of SSP-produced electricity. Enabled by analytical models and tools developed over the series of SSP studies, seven different system concepts as well as different technology choices within these concepts were quantitatively compared with one another on the basis of the mass and cost metrics suggested above. Accompanying sensitivity studies have permitted examination of how variations in the projected capabilities of different technologies could affect conclusions drawn from these analyses. This paper summarizes the results of these analytical efforts and from those results, identifies the most promising SSP concepts, including their key technologies and their comparative advantages and disadvantages. (C) 2003 Intemational Astronautical Federation. Published by Elsevier Science Ltd. All rights reserved. C1 Sci Applicat Int Corp, Schaumburg, IL USA. NASA, George C Marshall Space Flight Ctr, Flight Projects Directorate, Huntsville, AL 35812 USA. RP Feingold, H (reprint author), Sci Applicat Int Corp, Schaumburg, IL USA. NR 6 TC 7 Z9 7 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 AUG-NOV PY 2003 VL 53 IS 4-10 BP 547 EP 559 DI 10.1016/S0094-5765(03)00157-7 PG 13 WC Engineering, Aerospace SC Engineering GA 699XH UT WOS:000184081700032 ER PT J AU Roe, LB Uri, JJ AF Roe, LB Uri, JJ TI Research progress and accomplishments on International Space Station SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT 53rd Congress of the International-Astronautical-Federation (IAF) CY OCT 10, 2002 CL HOUSTON, TEXAS SP Internat Astronaut Fed (IAF) AB The first research payloads reached the International Space Station (ISS) more than two years ago, with research operating continuously since March 2001. Seven research racks are currently on-orbit, with three more arriving soon to expand science capabilities. Through the first five expeditions, 60 unique NASA-managed investigations from 11 nations have been supported, many continuing into later missions. More than 90,000 experiment hours have been completed, and more than 1,000 hours of crew time have been dedicated to research, numbers that grow daily. The multidisciplinary program includes research in life sciences, physical sciences, biotechnology, Earth sciences, technology demonstrations as well as commercial endeavors and educational activities. The Payload Operations and Integration Center monitors the onboard activities around the clock, working with numerous Principal Investigators and Payload Developers at their remote sites. Future years will see expansion of the station with research modules provided by the European Space Agency and Japan, which will be outfitted with additional research racks. (C) 2003 American Institute of Aeronautics and Astronautics. Published by Elsevier Science Ltd. All fights reserved. C1 NASA, Lyndon B Johnson Space Ctr, ISS Payloads Off, Houston, TX 77058 USA. RP Roe, LB (reprint author), NASA, Lyndon B Johnson Space Ctr, ISS Payloads Off, Houston, TX 77058 USA. NR 0 TC 3 Z9 3 U1 0 U2 3 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 AUG-NOV PY 2003 VL 53 IS 4-10 BP 665 EP 680 DI 10.1016/S0094-5765(03)00107-3 PG 16 WC Engineering, Aerospace SC Engineering GA 699XH UT WOS:000184081700044 PM 14649287 ER PT J AU Cook, S Hueter, U AF Cook, S Hueter, U TI NASA's Integrated Space Transportation Plan - 3(rd) generation Reusable Launch Vehicle technology update SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT 53rd Congress of the International-Astronautical-Federation (IAF) CY OCT 10, 2002 CL HOUSTON, TEXAS SP Internat Astronaut Fed (IAF) AB NASA's Integrated Space Transportation Plan (ISTP) calls for investments in Space Shuttle safety upgrades, second generation Reusable Launch Vehicle (RLV) advanced development and third generation RLV and in-space research and technology. NASA's third generation launch systems are to be fully reusable and operational by 2025. The goals for third generation launch systems are to reduce cost by a factor of 100 and improve safety by a factor of 10,000 over current systems. The Advanced Space Transportation Program Office (ASTP) at NASA's Marshall Space Flight Center in Huntsville, AL has the agency lead to develop third generation space transportation technologies. The Hypersonics Investment Area, part of ASTP, is developing the third generation launch vehicle technologies in two main areas, propulsion and airframes. The program's major investment is in hypersonic airbreathing propulsion since it offers the greatest potential for meeting the third generation launch vehicles. The program will mature the technologies in three key propulsion areas, scramjets, rocket-based combined cycle and turbine-based combination cycle. Ground and flight propulsion tests are being planned for the propulsion technologies. Airframe technologies will be matured primarily through ground testing. This paper describes NASA's activities in hypersonics. Current programs, accomplishments, future plans and technologies that are being pursued by the Hypersonics Investment Area under the Advanced Space Transportation Program Office will be discussed. (C) 2003 International Astronautical Federation. Published by Elsevier Science Ltd. All rights reserved. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Cook, S (reprint author), NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. NR 7 TC 8 Z9 8 U1 0 U2 8 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 AUG-NOV PY 2003 VL 53 IS 4-10 BP 719 EP 728 DI 10.1016/S0094-5765(03)00113-9 PG 10 WC Engineering, Aerospace SC Engineering GA 699XH UT WOS:000184081700047 ER PT J AU Mueller, JT Maldonado, H Driesman, AS AF Mueller, JT Maldonado, H Driesman, AS TI Stereo: The challenges SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT 53rd Congress of the International-Astronautical-Federation (IAF) CY OCT 10, 2002 CL HOUSTON, TEXAS SP Internat Astronaut Fed (IAF) AB The goal of the Solar-Terrestrial Relations Observatory (STEREO) mission is to advance understanding of the three-dimensional structure of the Sun's corona, and especially the of the origin of coronal mass ejections (CMEs), their evolution in the interplanetary medium, and the dynamic coupling between CMEs and the Earth environment. CMEs, the most energetic eruptions on the Sun, are the primary cause of major geomagnetic storms and are believed to be responsible for the largest solar energetic particles events. They may also be a critical element in the operation of the solar dynamo, because they appear to remove dynamo-generated magnetic flux from the Sun. The STEREO mission will study CMEs and the Sun's coronal structure using two spacecraft orbiting the Sun, one drifting ahead of the Earth and one behind. STEREO will obtain simultaneous extreme ultraviolet and visible image pairs, along with simultaneous measurements of fields and particles, at gradually increasing angular separations over the course of the mission. The STEREO spacecraft will be outfitted with two instrument suites and two instruments: IMPACT (In situ Measurements of Particles and CME Transients); SECCHI (Sun-Earth Connection Coronal and Heliospheric Investigation); PLASTIC (Plasma and Suprathermal Ion Composition); and SWAVES (STEREO/WAVES). STEREO Phase C/D confirmation occurred in March 2002; the dual observatories will be launched on a single Delta II from Cape Canaveral in November 2005. This presentation focuses on the goals and approach of the Mission. (C) 2003 International Astronautical Federation. Published by Elsevier Science Ltd. All rights reserved. C1 Johns Hopkins Univ, Appl Phys Lab, Dept Space, Laurel, MD 20723 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Mueller, JT (reprint author), Johns Hopkins Univ, Appl Phys Lab, Dept Space, 11100 Johns Hopkins Rd, Laurel, MD 20723 USA. NR 0 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 0094-5765 J9 ACTA ASTRONAUT JI Acta Astronaut. PD AUG-NOV PY 2003 VL 53 IS 4-10 BP 729 EP 738 DI 10.1016/S0094-5765(03)00122-X PG 10 WC Engineering, Aerospace SC Engineering GA 699XH UT WOS:000184081700048 ER PT J AU Launius, RD AF Launius, RD TI Evolving public perceptions of spaceflight in American culture SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT 53rd Congress of the International-Astronautical-Federation (IAF) CY OCT 10, 2002 CL HOUSTON, TEXAS SP Internat Astronaut Fed (IAF) ID SPACE AB There is a belief that exists in the United States about public support for NASA's activities. The belief is almost universally held that NASA and the cause of space exploration enjoyed outstanding public support and confidence in the 1960s during the era of Apollo and that public support waned in the post-Apollo era, only to sink to quite low depths in the decade of the 1990s. These beliefs are predicated on anecdotal evidence that should not be discounted, but empirical evidence gleaned from public opinion polling data suggest that some of these conceptions are totally incorrect and others are either incomplete or more nuanced than previously believed. This paper explores evolution of public support for space exploration since the 1960s. Using polling data from a variety of sources it presents trends over time and offers comments on the meaning of public perceptions for the evolution of space policy and the development of space exploration in the United States. C1 NASA, Washington, DC 20546 USA. RP Launius, RD (reprint author), NASA, Washington, DC 20546 USA. NR 23 TC 4 Z9 4 U1 0 U2 1 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 AUG-NOV PY 2003 VL 53 IS 4-10 BP 823 EP 831 DI 10.1016/S0094-5765(03)00119-X PG 9 WC Engineering, Aerospace SC Engineering GA 699XH UT WOS:000184081700058 PM 14649060 ER PT J AU DeVore, E Tarter, J Fisher, J O'Sullivan, K Pendleton, Y Taylor, S Burke, M AF DeVore, E Tarter, J Fisher, J O'Sullivan, K Pendleton, Y Taylor, S Burke, M TI Educating the next generation of SETI scientists: Voyages through time SO ACTA ASTRONAUTICA LA English DT Article; Proceedings Paper CT 53rd Congress of the International-Astronautical-Federation (IAF) CY OCT 10, 2002 CL HOUSTON, TEXAS SP Internat Astronaut Fed (IAF) AB The search for extraterrestrial intelligence (SETI) could succeed tomorrow, or not for many generations, or never. SETI scientists are very cognizant of the need to train the next generation of researchers who can carry on this vast scientific exploration. Previously, the SETI Institute has met this challenge by developing supplementary teachers' guides for elementary and middle schools called "Life In The Universe" and published by Teacher Ideas Press. Currently, we are engaged in a far more challenging project that is funded primarily by the National Science Foundation (NSF). The SETI Institute is creating a year long, interdisciplinary, high school science curriculum called "Voyages Through Time: Everything Evolves". We are using the theme of evolution to weave a panoramic vista for students that begins with the origin of the universe, encompasses our own origin and evolution, and looks at the evolution of technology and our possible future. By integrating different scientific and technical disciplines to explore how we answer fundamentally important questions, we hope to excite and motivate high school students with the opportunities offered by the way science is practiced today. We invite them to plan a future in which they help to enrich the answers to the big questions: Where did I come from? Where am I going? Is anybody else out there? Voyages Through Time consists of six modules on CD-ROMs for teachers and students that have been extensively tested both regionally and nationally. Publication is expected in 2003. The partners in the development of this curriculum are the SETI Institute, NASA Ames Research Center, California Academy of Sciences, and San Francisco State University. Voyages Through Time is funded by the NSF (DM # 9730693) with additional support from NASA, Hewlett Packard Company, The Foundation for Microbiology, and the Federated Charitable Campaign. (C) 2003 Published by Elsevier Science Ltd. C1 SETI Inst, Mountain View, CA USA. San Francisco State Univ, San Francisco, CA 94132 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Calif Acad Sci, San Francisco, CA 94118 USA. RP DeVore, E (reprint author), SETI Inst, Mountain View, CA USA. NR 5 TC 0 Z9 0 U1 0 U2 2 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 AUG-NOV PY 2003 VL 53 IS 4-10 BP 841 EP 846 DI 10.1016/S0094-5765(03)00121-8 PG 6 WC Engineering, Aerospace SC Engineering GA 699XH UT WOS:000184081700060 ER PT J AU Matsuura, Y Chernov, AA AF Matsuura, Y Chernov, AA TI Morphology and the strength of intermolecular contacts in protein crystals SO ACTA CRYSTALLOGRAPHICA SECTION D-BIOLOGICAL CRYSTALLOGRAPHY LA English DT Article ID HABIT-CONTROLLING FACTOR; EGG-WHITE LYSOZYME; X-RAY; COMBINATORIAL COMPATIBILITY; TETRAGONAL LYSOZYME; CRYSTALLIZATION; RESOLUTION; GROWTH; TEMPERATURE; SIMULATION AB The strengths of intermolecular contacts (macrobonds) and the areas occupied by each contact on the molecular surface were estimated in four polymorphic modifications of lysozyme crystals based on the bond strengths between individual atomic pairs belonging to the molecules in contact. It has been shown that the periodic bond chains of these macrobonds account for the morphology of protein crystals. The Coulombic contribution to the macrobond strength has also been estimated. Making use of the contact strengths and taking into account bond hydration, crystal-water interfacial energies were also estimated for different crystal faces. The areas of all contacts are mapped on the molecular surface, making use of a polar-coordinate representation of the contact. Comparing the locations of the intermolecular contacts in the different polymorphic crystal modifications, it is shown that these contacts can form a wide variety of patches on the molecular surface. The patches are located practically everywhere on the surface except for the inside of a concave active site. It is also shown that the contacts, which frequently involve water molecules, are formed by specific intermolecular hydrogen bonds on a background of non-specific attractive electrostatic interactions. Typical values of the macrobond strength are compared with the strength of association in other protein-complex systems. C1 Osaka Univ, Inst Prot Res, Suita, Osaka 5650871, Japan. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Matsuura, Y (reprint author), Osaka Univ, Inst Prot Res, 2-2 Yamadaoka, Suita, Osaka 5650871, Japan. NR 37 TC 34 Z9 34 U1 0 U2 9 PU BLACKWELL MUNKSGAARD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0907-4449 J9 ACTA CRYSTALLOGR D JI Acta Crystallogr. Sect. D-Biol. Crystallogr. PD AUG PY 2003 VL 59 BP 1347 EP 1356 DI 10.1107/S0907444903011107 PN 8 PG 10 WC Biochemical Research Methods; Biochemistry & Molecular Biology; Biophysics; Crystallography SC Biochemistry & Molecular Biology; Biophysics; Crystallography GA 704DM UT WOS:000184322700001 PM 12876335 ER PT J AU George, T Powers, R AF George, T Powers, R TI Closing the TRL gap SO AEROSPACE AMERICA LA English DT Editorial Material C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP George, T (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 0 TC 1 Z9 1 U1 0 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0740-722X J9 AEROSPACE AM JI Aerosp. Am. PD AUG PY 2003 VL 41 IS 8 BP 24 EP 26 PG 3 WC Engineering, Aerospace SC Engineering GA 708BZ UT WOS:000184548000010 ER PT J AU Smith, TB Schetz, JA Bui, TT AF Smith, TB Schetz, JA Bui, TT TI Development of direct-measuring skin-friction gauges for hypersonic flight tests SO AIAA JOURNAL LA English DT Article; Proceedings Paper CT 22nd AIAA Aerodynamic Measurement Technology and Ground Testing Conference CY JUN 24-26, 2002 CL ST LOUIS, MISSOURI SP Amer Inst Aeronaut & Astronaut ID ELEMENT AB A new type of direct-measuring skin-friction gauge was developed for the high-speed, high-temperature environment of turbulent boundary-layer flows in supersonic combustion ramjet (scramjet) engines, with tests progressing from ground tests to an actual hypersonic scramjet-integrated flight vehicle. The skin friction gauge was specifically developed for installation on the Hyper-X flight vehicle (X-43A). The design was nonnulling, with a sensing head that was flush with the model wall and surrounded by a small gap. Unlike previous skin-friction sensor designs, this gauge eliminated water cooling and gap-filling oil, in addition to a radically different flexure design. The design was verified by repeatable tests in a well-documented Mach 2.4 cold flow, with results within 10-15% of C-f estimates from simple theory. The sensor was qualified for flight through a rigorous series of environmental tests, including pressure, temperature, vibration, shock, acceleration, and heat flux tests. Finally, the skin-friction gauge was tested in the Hyper-X engine model (HXEM), a full-scale-partial-width wind-tunnel model of the flight vehicle engine, at Mach 6.5 enthalpy in a freejet facility at NASA Langley Research Center. Successful testing in the HXEM provided the final verification of the gauge before installation in the X-43A flight vehicle engine. C1 Virginia Polytech Inst & State Univ, Dept Aerosp & Ocean Engn, Blacksburg, VA 20461 USA. NASA, Dryden Flight Res Ctr, Prop & Performance Branch, Edwards AFB, CA 93523 USA. RP Smith, TB (reprint author), Atlantic Res Corp, Prop Test Grp, Bldg 50,5945 Wellington Rd, Gainesville, VA 20155 USA. NR 23 TC 2 Z9 2 U1 2 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 AUG PY 2003 VL 41 IS 8 BP 1429 EP 1437 DI 10.2514/2.2125 PG 9 WC Engineering, Aerospace SC Engineering GA 707GV UT WOS:000184503500004 ER PT J AU Venter, G Sobieszczanski-Sobieski, J AF Venter, G Sobieszczanski-Sobieski, J TI Particle swarm optimization SO AIAA JOURNAL LA English DT Article ID ALGORITHM AB How the search algorithm known as particle swarm optimization performs is demonstrated. Particle swarm optimization is applied to structural design problems, but the method has a much wider range of possible applications. Improvements are contributed to the particle swarm optimization algorithm and conclusions and recommendations as to the utility of the algorithm are made. Results of numerical experiments for both continuous and discrete applications are presented. The results indicate that the particle swarm optimization algorithm does locate the constrained minimum design in both continuous and discrete applications and problems with multiple local minima, with very good precision. Additionally, particle swarm optimization has the potential of efficient computation with very large numbers of concurrently operating processors. C1 Vanderplaats Res & Dev Inc, Colorado Springs, CO USA. NASA, Langley Res Ctr, Analyt & Computat Methods Branch, Hampton, VA 23665 USA. RP Vanderplaats Res & Dev Inc, 1767 S 8th St,Suite 100, Colorado Springs, CO USA. EM gventer@vrand.com; j.sobieski@larc.nasa.gov OI Venter, Gerhard/0000-0001-9513-9774 NR 13 TC 113 Z9 119 U1 0 U2 6 PU AMER INST AERONAUTICS ASTRONAUTICS PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0001-1452 EI 1533-385X J9 AIAA J JI AIAA J. PD AUG PY 2003 VL 41 IS 8 BP 1583 EP 1589 DI 10.2514/2.2111 PG 7 WC Engineering, Aerospace SC Engineering GA 707GV UT WOS:000184503500021 ER PT J AU Delcourt, DC Grimald, S Leblanc, F Berthelier, JJ Millilo, A Mura, A Orsini, S Moore, TE AF Delcourt, DC Grimald, S Leblanc, F Berthelier, JJ Millilo, A Mura, A Orsini, S Moore, TE TI A quantitative model of the planetary Na+ contribution to Mercury's magnetosphere SO ANNALES GEOPHYSICAE LA English DT Article DE magnetospheric physics; planetary magnetospheres; space plasma physics; charged particle motion and acceleration; numerical simulation studies ID PLASMA SHEET; MAGNETIC-FIELD; MAGNETOTAIL; ATMOSPHERE; PRECIPITATION; ACCELERATION; IONOSPHERE; SODIUM; IONS; SCATTERING AB We examine the circulation of heavy ions of planetary origin within Mercury's magnetosphere. Using single particle trajectory calculations, we focus on the dynamics of sodium ions, one of the main species that are ejected from the planet's surface. The numerical simulations reveal a significant population in the near-Mercury environment in the nightside sector, with energetic (several keV) Na+ densities that reach several tenths cm(-3) at planetary perihelion. At aphelion, a lesser (by about one order of magnitude) density contribution is obtained, due to weaker photon flux and solar wind flux. The numerical simulations also display several features of interest that follow from the small spatial scales of Mercury's magnetosphere. First, in contrast to the situation prevailing at Earth, ions in the magnetospheric lobes are found to be relatively energetic (a few hundreds of eV), despite the low-energy character of the exospheric source. This results from enhanced centrifugal acceleration during E x B transport over the polar cap. Second, the large Larmor radii in the mid-tail result in the loss of most Na+ into the dusk flank at radial distances greater than a few planetary radii. Because gyroradii are comparable to, or larger than, the magnetic field variation length scale, the Na+ C, motion is also found to be non-adiabatic throughout most of Mercury's equatorial magnetosphere, leading to chaotic scattering into the loss cone or meandering (Speiser-type) motion in the near-tail. As a direct consequence, a localized region of energetic Na+ precipitation develops at the planet's surface. In this region which extends over a wide range of longitudes at mid-latitudes (similar to30degrees-40degrees), one may expect additional sputtering of planetary material. C1 CNRS, CETP, St Maur des Fosses, France. CNRS, Serv Aeron, F-91371 Verrieres Le Buisson, France. CNR, IFSI, Rome, Italy. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Delcourt, DC (reprint author), CNRS, CETP, St Maur des Fosses, France. EM dominique.delcourt@cetp.ipsl.fr RI Moore, Thomas/D-4675-2012 OI Moore, Thomas/0000-0002-3150-1137 NR 47 TC 67 Z9 67 U1 0 U2 4 PU EUROPEAN GEOPHYSICAL SOC PI KATLENBURG-LINDAU PA MAX-PLANCK-STR 13, 37191 KATLENBURG-LINDAU, GERMANY SN 0992-7689 J9 ANN GEOPHYS-GERMANY JI Ann. Geophys. PD AUG PY 2003 VL 21 IS 8 BP 1723 EP 1736 PG 14 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA 775NG UT WOS:000189047100004 ER PT J AU Ray, RD Ponte, RM AF Ray, RD Ponte, RM TI Barometric tides from ECMWF operational analyses SO ANNALES GEOPHYSICAE LA English DT Article DE meteorology and atmospheric dynamics; waves and tides ID GENERAL-CIRCULATION MODEL; SURFACE PRESSURE; ATMOSPHERIC TIDES; SOLAR; VARIABILITY; OSCILLATIONS; GRACE AB The solar diurnal and semidiurnal tidal oscillations in surface pressure are extracted from the operational analysis product of the European Centre for Medium Range Weather Forecasting (ECMWF). For the semidiurnal tide this involves a special temporal interpolation, following Van den Dool et al. (1997). The resulting tides are compared with a "ground truth" tide data set, a compilation of well-determined tide estimates deduced from many long time series of station barometer measurements. These comparisons show that the ECMWF (analysis) tides are significantly more accurate than the tides deduced from two other widely available reanalysis products. Spectral analysis of ECMWF pressure series shows that the tides consist of sharp central peaks with modulating sidelines at integer multiples of 1 cycle/year, superimposed on a broad cusp of stochastic energy. The integrated energy in the cusp dominates that of the sidelines. This complicates the development of a simple empirical model that can characterize the full temporal variability of the tides. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Atmospher & Environm Res Inc, Lexington, MA USA. RP Ray, RD (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. EM richard.ray@gsfc.nasa.gov RI Ray, Richard/D-1034-2012; OI Ponte, Rui/0000-0001-7206-6461 NR 26 TC 85 Z9 87 U1 0 U2 6 PU EUROPEAN GEOPHYSICAL SOC PI KATLENBURG-LINDAU PA MAX-PLANCK-STR 13, 37191 KATLENBURG-LINDAU, GERMANY SN 0992-7689 J9 ANN GEOPHYS-GERMANY JI Ann. Geophys. PD AUG PY 2003 VL 21 IS 8 BP 1897 EP 1910 PG 14 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA 775NG UT WOS:000189047100016 ER PT J AU Hwang, PA Huang, NE Wang, DW AF Hwang, PA Huang, NE Wang, DW TI A note on analyzing nonlinear and nonstationary ocean wave data. SO APPLIED OCEAN RESEARCH LA English DT Article DE nlinear; nonstationary; Huang-Hilbert transformation; empirical mode decomposition; FFT; wavelet; frequency modulation; wave spectrum ID EMPIRICAL MODE DECOMPOSITION; HILBERT SPECTRUM AB The Huang-Hilbert transformation (HHT, composed of empirical mode decomposition and Hilbert transformation) can be applied to calculate the spectrum of nonlinear and nonstationary signals. The superior temporal and frequency resolutions of the HHT spectrum are illustrated by several examples in this article. The HHT analysis interprets wave nonlinearity in terms of frequency modulation instead of harmonic generation. The resulting spectrum contains much higher spectral energy at low frequency and sharper drop off at high frequency in comparison with the spectra derived from Fourier-based analysis methods (e.g. FFT and wavelet techniques). For wind generated waves, the spectral level of the Fourier spectrum is about two orders of magnitude smaller than that of the HHT spectrum at the first subharmonic of the peak frequency. The resulting average frequency as defined by the normalized first momentum of the spectrum is about 1.2 times higher in the Fourier-based spectra than that of the HHT spectrum. Published by Elsevier Ltd. C1 USN, Res Lab, Div Oceanog, Stennis Space Ctr, MS 39529 USA. NASA, Goddard Space Flight Ctr, Earth Sci Branch, Greenbelt, MD 20770 USA. RP Hwang, PA (reprint author), USN, Res Lab, Div Oceanog, Stennis Space Ctr, MS 39529 USA. EM paul.hwang@nrlssc.navy.mil NR 7 TC 50 Z9 52 U1 1 U2 13 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0141-1187 J9 APPL OCEAN RES JI Appl. Ocean Res. PD AUG PY 2003 VL 25 IS 4 BP 187 EP 193 DI 10.1016/j.apor.2003.11.001 PG 7 WC Engineering, Ocean; Oceanography SC Engineering; Oceanography GA 813ZB UT WOS:000220943900002 ER PT J AU Saha, TT Zhang, W AF Saha, TT Zhang, W TI Equal-curvature grazing-incidence x-ray telescopes SO APPLIED OPTICS LA English DT Article ID I TELESCOPE; MIRRORS; ABERRATION; ASTRONOMY AB We introduce a new type of x-ray telescope design, an equal-curvature telescope. We simply add a second-order axial sag to the base grazing-incidence cone-cone telescope. The radius of curvature of the sag terms is the same on the primary surface and on the secondary surface. The design is optimized such that the on-axis image spot at the focal plane is minimized. The on-axis rms spot diameter of two telescopes that we studied is less than 0.2 are sec. The off-axis performance is comparable with that of equivalent Wolter type 1 telescopes. (C) 2003 Optical Society of America. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Saha, TT (reprint author), NASA, Goddard Space Flight Ctr, Code 551, Greenbelt, MD 20771 USA. EM timo.saha@gsfc.nasa.gov NR 17 TC 11 Z9 11 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 AUG 1 PY 2003 VL 42 IS 22 BP 4599 EP 4605 DI 10.1364/AO.42.004599 PG 7 WC Optics SC Optics GA 705ED UT WOS:000184382000026 PM 12916628 ER PT J AU White, RL Helfand, DJ Becker, RH Gregg, MD Postman, M Lauer, TR Oegerle, W AF White, RL Helfand, DJ Becker, RH Gregg, MD Postman, M Lauer, TR Oegerle, W TI An I-band-selected sample of radio-emitting quasars: Evidence for a large population of red quasars SO ASTRONOMICAL JOURNAL LA English DT Article DE catalogs; galaxies : clusters : general; quasars : general; surveys ID QSO REDSHIFT SURVEY; DIGITAL SKY SURVEY; 1ST SURVEY; REDDEST QUASARS; SOURCE CATALOG; SPECTRA; IDENTIFICATIONS; ENVIRONMENTS; EXTINCTION; DISCOVERY AB We have constructed a sample of quasar candidates by comparing the FIRST radio survey with the 16 deg(2) Deeprange I-band survey carried out by Postman and coworkers. Spectroscopic follow-up of this magnitude-limited sample [I < 20.5, F-v (20 cm) > 1 mJy] has revealed 35 quasars, all but two of which are reported here for the first time. This sample contains some unusual broad absorption line (BAL) quasars, including the first radio-loud FR II BAL previously reported by Gregg and coworkers. Comparison of this sample with the FIRST Bright Quasar survey samples selected in a somewhat bluer band and with brighter magnitude limits reveals that the I-band-selected sample is redder by 0.25-0.5 mag in B-R and that the color difference is not explained by the higher mean redshift of this sample but must be intrinsic. Our small sample contains five quasars with unusually red colors, including three that appear very heavily reddened. Our data are fitted well with normal blue quasar spectra attenuated by more than 2.5 mag of extinction in the I band. These red quasars are only seen at low redshifts (z < 1.3). Even with a magnitude limit I < 20.5, our survey is deep enough to detect only the most luminous of these red quasars at z less than or similar to 1; similar objects at higher redshifts would fall below our I- band limit. Indeed, the five most luminous objects (using dereddened magnitudes) with z < 1.3 are all red. Our data strongly support the hypothesis that radio quasars are dominated by a previously undetected population of red, heavily obscured objects. Unless highly reddened quasars are preferentially also highly luminous, there must be an even larger, as yet undiscovered, population of red quasars at lower luminosity. We are likely to be finding only the most luminous tip of the red quasar iceberg. A comparison of the positions of the objects in our sample with the catalog of Deeprange cluster candidates reveals that five of our six z < 1 quasars are associated with cluster candidates of similar estimated redshifts. This association is very unlikely to be the result of chance. It has some surprising implications, including the possibility that up to half of the Deeprange clusters at z similar to 1 have associated quasars. C1 Space Telescope Sci Inst, Baltimore, MD 21218 USA. Columbia Univ, Dept Astron, New York, NY 10027 USA. Univ Calif Davis, Dept Phys, Davis, CA 95616 USA. Lawrence Livermore Natl Lab, Inst Geophys & Planetary Phys, Livermore, CA 94551 USA. Natl Opt Astron Observ, Tucson, AZ 85726 USA. NASA, Astron & Solar Phys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP White, RL (reprint author), Space Telescope Sci Inst, 3700 San Martin Dr, Baltimore, MD 21218 USA. RI Oegerle, William/C-9070-2012 NR 51 TC 45 Z9 45 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 AUG PY 2003 VL 126 IS 2 BP 706 EP 722 DI 10.1086/376597 PG 17 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 706GU UT WOS:000184446600009 ER PT J AU Su, KYL Hrivnak, BJ Kwok, S Sahai, R AF Su, KYL Hrivnak, BJ Kwok, S Sahai, R TI High-resolution near-infrared imaging and polarimetry of four proto-planetary nebulae SO ASTRONOMICAL JOURNAL LA English DT Article DE circumstellar matter; planetary nebulae : general; stars : AGB and post-AGB ID HUBBLE-SPACE-TELESCOPE; YOUNG STELLAR OBJECTS; POST-AGB STARS; PLANETARY-NEBULAE; INTERFEROMETRIC OBSERVATIONS; CIRCUMSTELLAR ENVELOPES; BIPOLAR NEBULA; EGG NEBULA; H-2 LINE; CRL 2688 AB High-resolution near-infrared Hubble Space Telescope (HST) NICMOS (F160W, F222M) images and polarization (2 mum) observations were made of four bipolar proto-planetary nebulae (PPNs): IRAS 17150-3224, 17441-2411, 17245-3951, and 16594-4656. The first three of these are viewed nearly edge-on, and for the first time the central stars in them are seen. Color maps reveal a reddened torus between the bipolr lobes in the edge-on cases, with bluer lobes. The polarization values are high, with maximum values ranging from 40% to 80%. The polarization patterns are basically centrosymmetric, with some deviations in the low-polarization equatorial regions. For IRAS 17150-3224, circumstellar arcs are seen at 1.6 mum, along with a newly discovered loop in the equatorial region. Bright caps are seen at the end of the lobes, indicating that they are not open-ended. A distinct point-symmetric pattern is seen in the strengths of the polarization vectors, especially in IRAS 17150-3224. HST NICMOS observations provide a valuable complement to the WFPC2 visible images in deriving the basic structure of bipolar PPNs. C1 Univ Calgary, Dept Phys & Astron, Calgary, AB T2N 1N4, Canada. Valparaiso Univ, Dept Phys & Astron, Valparaiso, IN 46383 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Su, KYL (reprint author), Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. EM ksu@as.arizona.edu; hrivnak@valpo.edu; kwok@iras.ucalgary.ca; Raghvendra.Sahai@jpl.nasa.gov RI Kwok, Sun/D-3080-2009 OI Kwok, Sun/0000-0001-7708-081X NR 37 TC 30 Z9 30 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-6256 J9 ASTRON J JI Astron. J. PD AUG PY 2003 VL 126 IS 2 BP 848 EP 862 DI 10.1086/376471 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 706GU UT WOS:000184446600020 ER PT J AU Lyke, JE Koenig, XP Barlow, MJ Gehrz, RD Woodward, CE Starrfield, S Pequignot, D Evans, A Salama, A Gonzalez-Riestra, R Greenhouse, MA Hjellming, RM Jones, TJ Krautter, J Ogelman, HB Wagner, RM Lumsden, SL Williams, RE AF Lyke, JE Koenig, XP Barlow, MJ Gehrz, RD Woodward, CE Starrfield, S Pequignot, D Evans, A Salama, A Gonzalez-Riestra, R Greenhouse, MA Hjellming, RM Jones, TJ Krautter, J Ogelman, HB Wagner, RM Lumsden, SL Williams, RE TI Abundance anomalies in CP Crucis (Nova Crux 1996) SO ASTRONOMICAL JOURNAL LA English DT Article DE circumstellar matter; novae, cataclysmic variables; stars : individual (Nova Crux 1996, CP Crucis) ID SHORT-WAVELENGTH SPECTROMETER; PHOTOIONIZATION MODEL; V1974 CYGNI; ISO OBSERVATIONS; EVOLUTION; LINE; EXTINCTION; NEBULAE; SHELLS AB We present spectroscopic observations of the classical nova CP Crucis ( Nova Crux 1996) obtained with the Infrared Space Observatory Short Wavelength Spectrometer (ISO SWS) and the Anglo-Australian Telescope using both the Infrared Imaging Spectrograph and the Royal Greenwich Observatory Spectrograph. From the expansion parallax, we find that CP Crucis lies at a distance of 2.6 +/- 0.5 kpc and reached a maximum M(V) of -8.7 at 0.96 days after discovery. We find abundance enhancements versus solar by mass of 75, 17, and 27 for N, O, and Ne, respectively. Additionally, we constrain the Mg abundance in the ejecta to be approximately solar. Abundance analysis suggests CP Crucis is an old Population I binary system. Combining the strong N and Ne abundances with the relatively low Mg abundance and a Ne/O ratio of 0.5, we propose that CP Crucis is an example of the "missing link'' between CO and ONeMg novae. C1 Univ Minnesota, Dept Astron, Minneapolis, MN 55455 USA. UCL, Dept Phys & Astron, London WC1E 6BT, England. Arizona State Univ, Dept Phys & Astron, Tempe, AZ 85287 USA. Observ Paris, F-92195 Meudon, France. Univ Keele, Dept Phys, Keele ST5 5BG, Staffs, England. ESA, Villafranca Castillo Satellite Tracking Stn, E-28080 Madrid, Spain. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Landessternwarte Heidelberg, D-69117 Heidelberg, Germany. Univ Wisconsin, Dept Astron, Madison, WI 53706 USA. Univ Arizona, Large Binocular Telescope Observ, Tucson, AZ 85721 USA. Univ Leeds, Dept Phys & Astron, Leeds LS2 9JT, W Yorkshire, England. Space Telescope Sci Inst, Baltimore, MD 21218 USA. RP Lyke, JE (reprint author), Univ Minnesota, Dept Astron, 116 Church St SE, Minneapolis, MN 55455 USA. RI Barlow, Michael/A-5638-2009 OI Barlow, Michael/0000-0002-3875-1171 NR 35 TC 17 Z9 17 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-6256 J9 ASTRON J JI Astron. J. PD AUG PY 2003 VL 126 IS 2 BP 993 EP 1005 DI 10.1086/376477 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 706GU UT WOS:000184446600031 ER PT J AU Dumas, C Smith, BA Terrile, RJ AF Dumas, C Smith, BA Terrile, RJ TI Hubble Space Telescope nicmos multiband photometry of Proteus and Puck SO ASTRONOMICAL JOURNAL LA English DT Article DE planets and satellites : individual (Proteus, Puck); techniques : photometric ID NEPTUNES RING ARCS; INNER SATELLITES; URANIAN SYSTEM; H2O ICE; URANUS; VOYAGER-2; SPECTRUM; SHAPES; RADII AB We report 1.1 - 2.4 mum multiband photometry of the small Uranian satellites Puck and Portia and of the small Neptunian satellite Proteus obtained with the Hubble Space Telescope and its near-infrared camera NICMOS. The surface of Puck ( and likely Portia) displays an absorption feature matching the 2.0 mum band of water ice. In the case of Proteus, a shallower absorption is detected in the long-wavelength region of the spectrum. Although water ice cannot be entirely ruled out, this feature could also be produced by C-H - or C = N - bearing material. Future spectroscopic observations at high angular resolution are needed to further investigate the nature of the compounds covering the surface of the small moons of Uranus and Neptune. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Hawaii, Inst Astron, Honolulu, HI 96822 USA. RP Dumas, C (reprint author), CALTECH, Jet Prop Lab, Mail Stop 183-501,4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 30 TC 1 Z9 1 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 AUG PY 2003 VL 126 IS 2 BP 1080 EP 1085 DI 10.1086/375909 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 706GU UT WOS:000184446600036 ER PT J AU Chambers, JE AF Chambers, JE TI Symplectic integrators with complex time steps SO ASTRONOMICAL JOURNAL LA English DT Article DE celestial mechanics; methods : n-body simulations; methods : numerical; stellar dynamics ID CLOSE ENCOUNTERS AB Symplectic integrators are a popular tool applied to a variety of numerical problems. Many symplectic methods are known, but those higher than second order must include some substeps that travel backward compared with the main integration. To compensate for this, some substeps must have large coefficients. This produces large error terms and reduces the efficiency of high-order symplectic algorithms. The constraint equations for the substeps of high-order algorithms often have complex solutions in addition to the known real ones. The complex solutions typically generate symplectic integrators with small substeps, so these algorithms have substantially smaller error terms than conventional algorithms. This makes them more efficient in principle. Here third-, fourth-, and sixth- order algorithms are developed and tested for problems in which the Hamiltonian is split into kinetic and potential energy terms, and also for perturbed Kepler problems. In addition, symplectic correctors are developed for the third- and fourth- order methods. It is shown that complex integrators with leading error terms that have strictly imaginary coefficients effectively behave as if they are 1 order higher than expected. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. SETI Inst, Mountain View, CA 94043 USA. RP Chambers, JE (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 15 TC 15 Z9 16 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 AUG PY 2003 VL 126 IS 2 BP 1119 EP 1126 DI 10.1086/376844 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 706GU UT WOS:000184446600041 ER PT J AU Kemper, F Stark, R Justtanont, K de Koter, A Tielens, AGGM Waters, LBFM Cami, J Dijkstra, C AF Kemper, F Stark, R Justtanont, K de Koter, A Tielens, AGGM Waters, LBFM Cami, J Dijkstra, C TI Mass loss and rotational CO emission from Asymptotic Giant Branch stars SO ASTRONOMY & ASTROPHYSICS LA English DT Article ID OH-IR STARS; OH/IR STARS; EVOLVED STARS; LOSS RATES; CIRCUMSTELLAR ENVELOPES; DUST SHELLS; MOLECULAR-EMISSION; INFRARED OBSERVATIONS; COMOVING-FRAME; LINE-PROFILES AB We present submillimeter observations of rotational transitions of carbon monoxide from J = 2 --> 1 up to 7 --> 6 for a sample of Asymptotic Giant Branch stars and red supergiants. It is the first time that the high transitions J = 6 --> 5 and 7 --> 6 are included in such a study. With line radiative transfer calculations, we aim to determine the mass-loss history of these stars by fitting the CO line intensities. We find that the observed line intensities of the high transitions, including the J = 4 --> 3 transition, are significantly lower than the predicted values. We conclude that the physical structure of the outflow of Asymptotic Giant Branch stars is more complex than previously thought. In order to understand the observed line intensities and profiles, a physical structure with a variable mass-loss rate and/or a gradient in stochastic gas velocity is required. A case study of the AGB star WX Psc is performed. We find that the CO line strengths may be explained by variations in mass-loss on time scales similar to those observed in the separated arc-like structures observed around post-AGB stars. In addition, a gradient in the stochastic velocity may play a role. Until this has been sorted out fully, any mass loss determinations based upon single CO lines will remain suspect. C1 Univ Amsterdam, Astron Inst Anton Pannekoek, NL-1098 SJ Amsterdam, Netherlands. Univ Calif Los Angeles, Div Astron, Los Angeles, CA 90095 USA. Max Planck Inst Radioastron, D-53121 Bonn, Germany. Stockholm Observ, SCFAB, S-10691 Stockholm, Sweden. Univ Groningen, Kapteyn Inst, NL-9700 AV Groningen, Netherlands. Lab Space Res, SRON, NL-9700 AV Groningen, Netherlands. Katholieke Univ Leuven, Inst Sterrekunde, B-3001 Heverlee, Belgium. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Kemper, F (reprint author), Univ Amsterdam, Astron Inst Anton Pannekoek, Kruislaan 403, NL-1098 SJ Amsterdam, Netherlands. RI Kemper, Francisca/D-8688-2011 OI Kemper, Francisca/0000-0003-2743-8240 NR 61 TC 60 Z9 60 U1 0 U2 0 PU E D P SCIENCES PI LES ULIS CEDEXA PA 7, AVE DU HOGGAR, PARC D ACTIVITES COURTABOEUF, BP 112, F-91944 LES ULIS CEDEXA, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD AUG PY 2003 VL 407 IS 2 BP 609 EP 629 DI 10.1051/0004-6361:20030701 PG 21 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 708CV UT WOS:000184550300023 ER PT J AU Katsiyannis, AC Williams, DR McAteer, RTJ Gallagher, PT Keenan, FP Murtagh, F AF Katsiyannis, AC Williams, DR McAteer, RTJ Gallagher, PT Keenan, FP Murtagh, F TI Eclipse observations of high-frequency oscillations in active region coronal loops SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE MHD; waves; eclipses; Sun : activity; Sun : corona; Sun : oscillations ID TOTAL SOLAR ECLIPSE; TRANSITION-REGION; WAVELET ANALYSIS; HEAT AB One of the mechanisms proposed for heating the corona above solar active regions is the damping of magnetohydrodynamic (MHD) waves. Continuing on previous work, we provide observational evidence for the existence of high-frequency MHD waves in coronal loops observed during the August 1999 total solar eclipse. A wavelet analysis is used to identify twenty 4 x 4 arcsec(2) areas showing intensity oscillations. All detections lie in the frequency range 0.15 - 0.25 Hz ( 7 - 4 s), last for at least 3 periods at a confidence level of more than 99% and arise just outside known coronal loops. This leads us to suggest that they occur in low emission-measure or different temperature loops associated with the active region. C1 Queens Univ Belfast, Dept Pure & Appl Phys, Belfast BT7 1NN, Antrim, North Ireland. UCL, Mullard Space Sci Lab, Dorking RH5 6NT, Surrey, England. NASA, L3 Commun EER Syst Inc, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Queens Univ Belfast, Sch Comp Sci, Belfast BT7 1NN, Antrim, North Ireland. Observ Astron, F-67000 Strasbourg, France. RP Katsiyannis, AC (reprint author), Queens Univ Belfast, Dept Pure & Appl Phys, Belfast BT7 1NN, Antrim, North Ireland. EM A.Katsiyannis@qub.ac.uk RI McAteer, R. T. James/D-3736-2011; Williams, David/E-6676-2011; Katsiyannis, Thanassis/L-8496-2013; Gallagher, Peter/C-7717-2011 OI Williams, David/0000-0001-9922-8117; Gallagher, Peter/0000-0001-9745-0400 NR 27 TC 47 Z9 47 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 AUG PY 2003 VL 406 IS 2 BP 709 EP 714 DI 10.1051/0004-6361:20030458 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 702KC UT WOS:000184222200035 ER PT J AU Boezio, M Bonvicini, V Schiavon, P Vacchi, A Zampa, N Bergstrom, D Carlson, P Francke, T Hansen, P Mocchiutti, E Suffert, M Hof, M Kremer, J Menn, W Simon, M Ambriola, M Bellotti, R Cafagna, F Ciacio, F Circella, M De Marzo, CN Finetti, N Papini, P Piccardi, S Spillantini, P Vannuccini, E Bartalucci, S Ricci, M Casolino, M De Pascale, MP Morselli, A Picozza, P Sparvoli, R Mitchell, JW Ormes, JF Stephens, SA Streitmatter, RE Bravar, U Stochaj, SJ AF Boezio, M Bonvicini, V Schiavon, P Vacchi, A Zampa, N Bergstrom, D Carlson, P Francke, T Hansen, P Mocchiutti, E Suffert, M Hof, M Kremer, J Menn, W Simon, M Ambriola, M Bellotti, R Cafagna, F Ciacio, F Circella, M De Marzo, CN Finetti, N Papini, P Piccardi, S Spillantini, P Vannuccini, E Bartalucci, S Ricci, M Casolino, M De Pascale, MP Morselli, A Picozza, P Sparvoli, R Mitchell, JW Ormes, JF Stephens, SA Streitmatter, RE Bravar, U Stochaj, SJ TI The cosmic-ray proton and helium spectra measured with the CAPRICE98 balloon experiment SO ASTROPARTICLE PHYSICS LA English DT Article DE cosmic rays; elementary particles; RICH detectors; balloons ID GAS-RICH DETECTOR; MAGNETIC SPECTROMETER; ATMOSPHERIC DEPTHS; PERFORMANCE; SPACE; BESS; ANTIPROTONS; ANTIMATTER; RADIATION; NUCLEI AB A new measurement of the primary cosmic-ray proton and helium fluxes from 3 to 350 GeV was carried out by the balloon-borne CAPRICE experiment in 1998. This experimental setup combines different detector techniques and has excellent particle discrimination capabilities allowing clear particle identification. Our experiment has the capability to determine accurately detector selection efficiencies and systematic errors associated with them. Furthermore, it can check for the first time the energy determined by the magnet spectrometer by using the Cherenkov angle measured by the RICH detector well above 20 GeV n(-1). The analysis of the primary proton and helium components is described here and the results are compared with other recent measurements using other magnet spectrometers. The observed energy spectra at the top of the atmosphere can be represented by (1.27 +/- 0.09) x 10(4) E-2.75+/-0.02 particles (m(2) GeV sr s)(-1), where E is the kinetic energy in GeV, for protons between 20 and 350 GeV and (4.8 +/- 0.8) X 10(2) E-2 67+/-0.03 particles (m(2) GeV n(-1) sr s)(-1), where E is the kinetic energy in GeV per nucleon, for helium nuclei between 15 and 150 GeV n(-1). (C) 2003 Elsevier Science B.V. All rights reserved. C1 AlbaNova Univ Ctr, SCFAB, KTH, Royal Inst Technol, S-10691 Stockholm, Sweden. Sezione INFN Trieste, I-34147 Trieste, Italy. Univ Trieste, I-34147 Trieste, Italy. New Mexico State Univ, RL Golden Particle Astrophys Lab, Las Cruces, NM 88003 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Roma Tor Vergata, I-00133 Rome, Italy. Sezione INFM Roma 2, I-00133 Rome, Italy. Ist Nazl Fis Nucl, Lab Nazl Frascati, I-00044 Frascati, Italy. Univ Florence, I-50125 Florence, Italy. Sezione INFN Firenze, I-50125 Florence, Italy. Univ Bari, I-70126 Bari, Italy. Sezione INFN Bari, I-70126 Bari, Italy. Univ Gesamthsch Siegen, D-57068 Siegen, Germany. Ctr Rech Nucl, F-67037 Strasbourg, France. RP Mocchiutti, E (reprint author), AlbaNova Univ Ctr, SCFAB, KTH, Royal Inst Technol, S-10691 Stockholm, Sweden. RI Morselli, Aldo/G-6769-2011; Cafagna, Francesco/A-9299-2010; Mocchiutti, Emiliano/I-8049-2013; Vacchi, Andrea/C-1291-2010; OI Morselli, Aldo/0000-0002-7704-9553; Cafagna, Francesco/0000-0002-7450-4784; Mocchiutti, Emiliano/0000-0001-7856-551X; Vacchi, Andrea/0000-0003-3855-5856; Bellotti, Roberto/0000-0003-3198-2708; casolino, marco/0000-0001-6067-5104; Sparvoli, Roberta/0000-0002-6314-6117; Picozza, Piergiorgio/0000-0002-7986-3321; Papini, Paolo/0000-0003-4718-2895; Boezio, Mirko/0000-0002-8015-2981 NR 44 TC 86 Z9 86 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0927-6505 J9 ASTROPART PHYS JI Astropart Phys. PD AUG PY 2003 VL 19 IS 5 BP 583 EP 604 DI 10.1016/S0927-6505(02)00267-0 PG 22 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 697VN UT WOS:000183964100001 ER PT J AU Benson, BA Church, SE Ade, PAR Bock, JJ Ganga, KM Hinderks, JR Mauskopf, PD Philhour, B Runyan, MC Thompson, KL AF Benson, BA Church, SE Ade, PAR Bock, JJ Ganga, KM Hinderks, JR Mauskopf, PD Philhour, B Runyan, MC Thompson, KL TI Peculiar velocity limits from measurements of the spectrum of the Sunyaev-Zeldovich effect in six clusters of galaxies SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmic microwave background; cosmology : observations; galaxies : clusters : general; large-scale structure of universe ID X-RAY-CLUSTER; MICROWAVE BACKGROUND COMPTONIZATION; HOT INTRACLUSTER GAS; RELATIVISTIC CORRECTIONS; HUBBLE CONSTANT; DISTANT CLUSTERS; RX J1347-1145; SCALE; TEMPERATURE; CONSTRAINTS AB We have made measurements of the Sunyaev-Zeldovich (SZ) effect in six galaxy clusters at z > 0.2 using the Sunyaev-Zeldovich Infrared Experiment (SuZIE II) in three frequency bands between 150 and 350 GHz. Simultaneous multifrequency measurements have been used to distinguish between thermal and kinematic components of the SZ effect and to significantly reduce the effects of variations in atmospheric emission that can otherwise dominate the noise. We have set limits to the peculiar velocities of each cluster with respect to the Hubble flow and have used the cluster sample to set a 95% confidence limit of less than 1420 km s(-1) to the bulk flow of the intermediate-redshift universe in the direction of the cosmic microwave background dipole. This is the first time that SZ measurements have been used to constrain bulk flows. We show that systematic uncertainties in peculiar velocity determinations from the SZ effect are likely to be dominated by submillimeter point sources, and we discuss the level of this contamination. C1 Stanford Univ, Stanford, CA 94305 USA. Univ Wales Coll Cardiff, Dept Phys & Astron, Cardiff CF24 3YB, S Glam, Wales. CALTECH, Ctr Infrared Proc & Anal, Pasadena, CA 91125 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Chicago, Chicago, IL 60637 USA. RP Benson, BA (reprint author), Stanford Univ, 382 Via Pueblo,Varian Bldg, Stanford, CA 94305 USA. NR 64 TC 57 Z9 57 U1 0 U2 1 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 AUG 1 PY 2003 VL 592 IS 2 BP 674 EP 691 DI 10.1086/375864 PN 1 PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 705RG UT WOS:000184408100003 ER PT J AU Mukherjee, P Coble, K Dragovan, M Ganga, K Kovac, J Ratra, B Souradeep, T AF Mukherjee, P Coble, K Dragovan, M Ganga, K Kovac, J Ratra, B Souradeep, T TI Galactic foreground constraints from the Python V cosmic microwave background anisotropy data SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmic microwave background; cosmology : observations; diffuse radiation; dust, extinction ID DARK-MATTER COSMOGONIES; UCSB SOUTH-POLE; SPINNING DUST GRAINS; FLAT-LAMBDA; ANGULAR SCALES; BOOMERANG MAPS; TENERIFE DATA; EMISSION; SKY; RADIATION AB We constrain Galactic foreground contamination of the Python V cosmic microwave background anisotropy data by cross-correlating it with foreground contaminant emission templates. To model foreground emission, we use 100 and 12 mum dust templates and two point-source templates based on the Parkes-MIT-NRAO survey. The analysis takes account of intermodulation correlations in eight modulations of the data that are sensitive to a large range of angular scales and also densely sample a large area of sky. As a consequence, the analysis here is highly constraining. We find little evidence for foreground contamination in an analysis of the whole data set. However, there is indication that foregrounds are present in the data from the larger angular scale modulations of those Python V fields that overlap the region scanned earlier by the University of California at Santa Barbara South Pole 1994 experiment. This is an independent consistency cross-check of findings from the South Pole 1994 data. C1 Kansas State Univ, Dept Phys, Manhattan, KS 66506 USA. Univ Chicago, Enrico Fermi Inst, Chicago, IL 60637 USA. Adler Planetarium & Astron Museum, Chicago, IL 60605 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. CALTECH, Ctr Infrared Proc & Anal, Pasadena, CA 91125 USA. IUCAA, Pune 411007, Maharashtra, India. RP Mukherjee, P (reprint author), Univ Oklahoma, Dept Phys & Astron, 440 W Brooks St, Norman, OK 73019 USA. RI Ratra, Bharat/I-4979-2012 NR 52 TC 15 Z9 15 U1 0 U2 0 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 AUG 1 PY 2003 VL 592 IS 2 BP 692 EP 698 DI 10.1086/375860 PN 1 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 705RG UT WOS:000184408100004 ER PT J AU Ptak, A Heckman, T Levenson, NA Weaver, K Strickland, D AF Ptak, A Heckman, T Levenson, NA Weaver, K Strickland, D TI A Chandra survey of the nearest ultraluminous infrared galaxies: Obscured active galactic nuclei or superstarbursts? SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : active; galaxies : evolution; galaxies : starburst; X-rays : galaxies ID X-RAY-EMISSION; RESOLUTION CO OBSERVATIONS; 1 JY SAMPLE; STARBURST GALAXIES; OPTICAL SPECTROSCOPY; ASCA OBSERVATIONS; SEYFERT-GALAXIES; STAR-FORMATION; IRAS GALAXIES; ENERGY-SOURCE AB We present initial results from a Chandra survey of a complete sample of the eight nearest (z less than or equal to 0.04) ultraluminous IR galaxies (ULIRGs) and also include the IR-luminous galaxy NGC 6240 for comparison. In this paper we use the hard X-rays (2 - 8 keV) to search for the possible presence of an obscured active galactic nucleus (AGN). In every case, a hard X-ray source is detected in the nuclear region. If we divide the sample according to the optical/IR spectroscopic classification (starburst vs. AGN), we find that the five "starburst'' ULIRGs have hard X-ray luminosities about an order of magnitude smaller than the three "AGN'' ULIRGs. NGC 6240 has an anomalously high hard X-ray luminosity compared to the starburst ULIRGs. The Fe-Kalpha line is convincingly detected in only two ULIRGs. The weakness of the Fe-K emission in these ULIRGs generally suggests that the hard X-ray spectrum is not dominated by reflection from high-N-H neutral material. The hard X-ray continuum flux ranges from a few x 10(-3) to a few x 10(-5) of the far-IR flux, similar to values in pure starbursts and several orders of magnitude smaller than in Compton-thin AGNs. The upper limits on the ratio of the Fe-Kalpha-to-far-IR flux are below the values measured in Compton-thick type 2 Seyfert galaxies. While very large column densities of molecular gas are observed in the nuclei of these galaxies, we find no evidence that the observed X-ray sources are obscured by Compton-thick material. Thus, our new hard X-ray data do not provide direct evidence that powerful "buried quasars'' dominate the overall energetics of most ULIRGs. C1 Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. Univ Kentucky, Dept Phys & Astron, Lexington, KY 40506 USA. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Ptak, A (reprint author), Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. RI Ptak, Andrew/D-3574-2012; OI Levenson, Nancy A./0000-0003-4209-639X NR 85 TC 116 Z9 116 U1 0 U2 1 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 AUG 1 PY 2003 VL 592 IS 2 BP 782 EP 803 DI 10.1086/375766 PN 1 PG 22 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 705RG UT WOS:000184408100011 ER PT J AU Clayton, GC Gordon, KD Salama, F Allamandola, LJ Martin, PG Snow, TP Whittet, DCB Witt, AN Wolff, MJ AF Clayton, GC Gordon, KD Salama, F Allamandola, LJ Martin, PG Snow, TP Whittet, DCB Witt, AN Wolff, MJ TI The role of polycyclic aromatic hydrocarbons in ultraviolet extinction. I. Probing small molecular polycyclic aromatic hydrocarbons SO ASTROPHYSICAL JOURNAL LA English DT Article DE dust, extinction; ISM : lines and bands; ISM : molecules; ultraviolet : ISM ID DIFFUSE INTERSTELLAR-MEDIUM; SMALL-MAGELLANIC-CLOUD; INFRARED-EMISSION BANDS; REFLECTION NEBULAE; ASTROPHYSICAL IMPLICATIONS; GRAIN MANTLES; MILKY-WAY; ISO-SWS; DUST; PAHS AB We have obtained new Hubble Space Telescope/Space Telescope Imaging Spectrograph spectra to search for structure in the ultraviolet interstellar extinction curve, with particular emphasis on a search for absorption features produced by polycyclic aromatic hydrocarbons (PAHs). The presence of these molecules in the interstellar medium has been postulated to explain the infrared emission features seen in the 3 - 13 mum spectra of numerous sources. Ultraviolet (UV) spectra are uniquely capable of identifying specific PAH molecules. We obtained high signal-to-noise ratio UV spectra of stars that are significantly more reddened than those observed in previous studies. These data put limits on the role of small ( 30 - 50 carbon atoms) PAHs in UV extinction and call for further observations to probe the role of larger PAHs. PAHs are of importance because of their ubiquity and high abundance inferred from the infrared data, and also because they may link the molecular and dust phases of the interstellar medium. A presence or absence of UV absorption bands due to PAHs could be a definitive test of this hypothesis. We should be able to detect a 20 Angstrom wide feature down to a 3 sigma limit of similar to 0.02 A(V). No such absorption features are seen other than the well-known 2175 Angstrom bump. C1 Louisiana State Univ, Dept Phys & Astron, Baton Rouge, LA 70803 USA. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA. Univ Toronto, Canadian Inst Theoret Astrophys, Toronto, ON M5S 3H8, Canada. Univ Colorado, Ctr Astrophys & Space Astron, Boulder, CO 80309 USA. Rensselaer Polytech Inst, Dept Phys & Astron, Troy, NY 12180 USA. Univ Toledo, Ritter Observ, Toledo, OH 43606 USA. Space Sci Inst, Boulder, CO 80303 USA. RP Clayton, GC (reprint author), Louisiana State Univ, Dept Phys & Astron, Baton Rouge, LA 70803 USA. RI Salama, Farid/A-8787-2009 OI Salama, Farid/0000-0002-6064-4401 NR 58 TC 48 Z9 49 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 AUG 1 PY 2003 VL 592 IS 2 BP 947 EP 952 DI 10.1086/375771 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 705RG UT WOS:000184408100022 ER PT J AU Davis, SS AF Davis, SS TI A simplified model for an evolving protoplanetary nebula SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; methods : analytical; solar system : formation ID SOLAR NEBULA; ACCRETION DISKS; EVOLUTION; TURBULENCE; FRACTIONATION AB The dynamic evolution of a protoplanetary nebula is investigated using analytical solutions of the surface density transport equations. Constant- and so-called beta-viscosity turbulence models are compared with a functional analytical model and the well-known alpha-viscosity formulation. The model presented here is related to a number of simplified disk evolution models but is also associated with beta-viscosity models based on hydrodynamic generation of turbulence. The beta-viscosity model, heretofore used for steady state disks, is shown to be a useful approximation for disk evolution problems. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Davis, SS (reprint author), NASA, Ames Res Ctr, MS 245-3, Moffett Field, CA 94035 USA. NR 17 TC 7 Z9 7 U1 0 U2 1 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 AUG 1 PY 2003 VL 592 IS 2 BP 1193 EP 1200 DI 10.1086/375730 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 705RG UT WOS:000184408100044 ER PT J AU Thejappa, G Zlobec, P MacDowall, RJ AF Thejappa, G Zlobec, P MacDowall, RJ TI Polarization and fragmentation of solar type II radio bursts SO ASTROPHYSICAL JOURNAL LA English DT Article DE shock waves; Sun : radio radiation ID INTERPLANETARY SHOCKS; ULYSSES OBSERVATIONS; LANGMUIR-WAVES; CORONA; ACCELERATION; ELECTRONS AB Solar type II radio bursts are the electromagnetic signatures of collisionless shocks propagating radially outward in the solar atmosphere. The Zurich radio spectrograph has detected a fragmented type II burst at high frequencies. The Trieste polarimeter found this event to contain a high degree of left-hand polarization. These observations indicate that (1) the fragmented type II event is probably emitted at the fundamental of the electron plasma frequency f(pe) as one of the magnetoionic modes, namely, the ordinary (O) mode, (2) the fragmentation is due to fluctuations in the efficiency of linear coupling of Langmuir waves with escaping radiation at sharp density gradients associated with the oncoming shock, and (3) the key role of backscattering Langmuir waves in the direction of the oncoming shock is probably played by one of the saturation mechanisms, such as induced scattering of Langmuir waves on thermal ions or the electrostatic decay instability. C1 Univ Maryland, Dept Astron, College Pk, MD 20742 USA. Osserv Astron Trieste, I-34131 Trieste, Italy. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Thejappa, G (reprint author), Univ Maryland, Dept Astron, College Pk, MD 20742 USA. RI MacDowall, Robert/D-2773-2012 NR 23 TC 3 Z9 3 U1 0 U2 1 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 AUG 1 PY 2003 VL 592 IS 2 BP 1234 EP 1240 DI 10.1086/375859 PN 1 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 705RG UT WOS:000184408100048 ER PT J AU Colavita, M Akeson, R Wizinowich, P Shao, M Acton, S Beletic, J Bell, J Berlin, J Boden, A Booth, A Boutell, R Chaffee, F Chan, D Chock, J Cohen, R Crawford, S Creech-Eakman, M Eychaner, G Felizardo, C Gathright, J Hardy, G Henderson, H Herstein, J Hess, M Hovland, E Hrynevych, M Johnson, R Kelley, J Kendrick, R Koresko, C Kurpis, P Le Mignant, D Lewis, H Ligon, E Lupton, W McBride, D Mennesson, B Millan-Gabet, R Monnier, J Moore, J Nance, C Neyman, C Niessner, A Palmer, D Reder, L Rudeen, A Saloga, T Sargent, A Serabyn, E Smythe, R Stomski, P Summers, K Swain, M Swanson, P Thompson, R Tsubota, K Tumminello, A van Belle, G Vasisht, G Vause, J Walker, J Wallace, K Wehmeier, U AF Colavita, M Akeson, R Wizinowich, P Shao, M Acton, S Beletic, J Bell, J Berlin, J Boden, A Booth, A Boutell, R Chaffee, F Chan, D Chock, J Cohen, R Crawford, S Creech-Eakman, M Eychaner, G Felizardo, C Gathright, J Hardy, G Henderson, H Herstein, J Hess, M Hovland, E Hrynevych, M Johnson, R Kelley, J Kendrick, R Koresko, C Kurpis, P Le Mignant, D Lewis, H Ligon, E Lupton, W McBride, D Mennesson, B Millan-Gabet, R Monnier, J Moore, J Nance, C Neyman, C Niessner, A Palmer, D Reder, L Rudeen, A Saloga, T Sargent, A Serabyn, E Smythe, R Stomski, P Summers, K Swain, M Swanson, P Thompson, R Tsubota, K Tumminello, A van Belle, G Vasisht, G Vause, J Walker, J Wallace, K Wehmeier, U TI Observations of DG Tauri with the Keck interferometer SO ASTROPHYSICAL JOURNAL LA English DT Article DE circumstellar matter; instrumentation : interferometers; stars : pre-main-sequence ID YOUNG STELLAR OBJECTS; PALOMAR TESTBED INTERFEROMETER; CIRCUMSTELLAR DISKS; AU SCALE; STARS; JET; SYSTEM AB We present the first science results from the Keck Interferometer, a direct-detection infrared interferometer utilizing the two 10 m Keck telescopes. The instrument and system components are briefly described. We then present observations of the T Tauri object DG Tau, which is resolved by the interferometer. The resolved component has a radius of 0.12 - 0.24 AU, depending on the assumed stellar and extended component fluxes and the model geometry used. Possible origins and implications of the resolved emission are discussed. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Michelson Sci Ctr, Pasadena, CA 91125 USA. Calif Assoc Res Astron, WM Keck Observ, Kamuela, HI 96743 USA. Univ Michigan, Ann Arbor, MI 48109 USA. RP Colavita, M (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. OI Monnier, John D/0000-0002-3380-3307 NR 28 TC 41 Z9 41 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 AUG 1 PY 2003 VL 592 IS 2 BP L83 EP L86 DI 10.1086/377704 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 705RJ UT WOS:000184408300008 ER PT J AU Habbal, SR Arndt, MB Nayfeh, MH Arnaud, J Johnson, J Hegwer, S Woo, R Ene, A Habbal, F AF Habbal, SR Arndt, MB Nayfeh, MH Arnaud, J Johnson, J Hegwer, S Woo, R Ene, A Habbal, F TI On the detection of the signature of silicon nanoparticle dust grains in coronal holes SO ASTROPHYSICAL JOURNAL LA English DT Article DE dust, extinction; eclipses; polarization; Sun : corona; Sun : infrared; Sun : magnetic fields ID 1991 SOLAR ECLIPSE; INTERPLANETARY DUST; INFRARED OBSERVATIONS; THERMAL RADIATION; CIRCUMSOLAR DUST; MAGNETIC-FIELD; EMISSION-LINE; POLARIZATION AB We report on polarization measurements in the Fe XIII line at 1074.7 nm made during the total solar eclipse of 2001 June 21, which yielded the first signature of interplanetary dust in the inner corona. In the first-ever images at this wavelength, the signature of dust appears as a tangentially polarized emission in the radial extension of the low-temperature and low-density coronal holes as opposed to a predominantly radial polarization direction in the rest of the corona. The observed emission and polarization are attributed to fluorescence from silicon nanoparticle dust grains in the inner corona. C1 Univ Coll Wales, Dept Phys, Aberystwyth SY23 3BZ, Dyfed, Wales. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Bridgewater State Coll, Dept Phys, Bridgewater, MA 02325 USA. Univ Illinois, Dept Phys, Urbana, IL 61801 USA. Observ Midi Pyrenees, F-31400 Toulouse, France. Electricon, Boulder, CO 80304 USA. Natl Solar Observ, Sunspot, NM 88349 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Stanford Univ, Dept Phys, Stanford, CA 94305 USA. Univ Texas, Dept Mech Engn, Austin, TX 78712 USA. RP Habbal, SR (reprint author), Univ Coll Wales, Dept Phys, Aberystwyth SY23 3BZ, Dyfed, Wales. NR 21 TC 17 Z9 17 U1 1 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 AUG 1 PY 2003 VL 592 IS 2 BP L87 EP L90 DI 10.1086/377678 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 705RJ UT WOS:000184408300009 ER PT J AU Verner, E Bruhweiler, F Verner, D Johansson, S Gull, T AF Verner, E Bruhweiler, F Verner, D Johansson, S Gull, T TI Revisited abundance diagnostics in quasars: Fe II/mg II ratios SO ASTROPHYSICAL JOURNAL LA English DT Article DE atomic processes; line : formation; methods : numerical; quasars : emission lines ID BROAD EMISSION FEATURES; ACTIVE GALACTIC NUCLEI; CHEMICAL EVOLUTION; QSOS; LINES; SPECTRA AB Both the Fe II UV emission in the 2000 - 3000 Angstrom region [Fe II(UV)] and resonance emission-line complex of Mg II at 2800 Angstrom are prominent features in quasar spectra. The observed Fe II(UV)/Mg II emission ratios have been proposed as means to measure the buildup of the Fe abundance relative to that of the alpha-elements C, N, O, Ne, and Mg as a function of redshift. The current observed ratios show large scatter and no obvious dependence on redshift. Thus, it remains unresolved whether a dependence on redshift exists and whether the observed Fe II(UV)/Mg II ratios represent a real nucleosynthesis diagnostic. We have used our new 830 level model atom for Fe+ in photoionization calculations, reproducing the physical conditions in the broad-line regions of quasars. This modeling reveals that interpretations of high values of Fe II(UV)/Mg II are sensitive not only to Fe and Mg abundance, but also to other factors such as microturbulence, density, and properties of the radiation field. We find that the Fe II(UV)/ Mg II ratio combined with Fe II( UV)/ Fe II( optical) emission ratio, where Fe II( optical) denotes Fe II emission in 4000 - 6000 Angstrom band, can be used as a reliable nucleosynthesis diagnostic for the Fe/Mg abundance ratios for the physical conditions relevant to the broad-line regions of quasars. This has extreme importance for quasar observations with the Hubble Space Telescope and also with the future James Webb Space Telescope. C1 Catholic Univ Amer, Dept Phys, IACS, Washington, DC 20064 USA. NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. Lund Univ, Lund Observ, S-22100 Lund, Sweden. RP Verner, E (reprint author), Catholic Univ Amer, Dept Phys, IACS, Washington, DC 20064 USA. RI Gull, Theodore/D-2753-2012 OI Gull, Theodore/0000-0002-6851-5380 NR 16 TC 32 Z9 32 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 AUG 1 PY 2003 VL 592 IS 2 BP L59 EP L62 DI 10.1086/377571 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 705RJ UT WOS:000184408300002 ER PT J AU Prieto, CA Lambert, DL Hubeny, I Lanz, T AF Prieto, CA Lambert, DL Hubeny, I Lanz, T TI Non-LTE model atmospheres for late-type stars. I. A collection of data for light neutral and singly ionized atoms SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article DE atomic data; radiative transfer; stars : atmospheres ID PHOTOIONIZATION CROSS-SECTIONS; ASTROPHYSICALLY ABUNDANT ELEMENTS; RECOMBINATION RATE COEFFICIENTS; STELLAR ATMOSPHERES; IONIZATION FRACTIONS; SOLAR GRANULATION; IRON PROJECT; ION SPECTRA AB With the goal of producing a reliable set of model atoms and singly ionized ions for use in building NLTE model atmospheres, we have combined measured energy levels, critically compiled line transition probabilities, and resonance-averaged calculations of photoionization cross sections. A majority of the elements from Li to Ca are considered, covering most of the important species in late-type atmospheres. These include elements that contribute free electrons and/or continuous opacity in the ultraviolet (e.g., Mg and Si), as well as trace elements whose abundance determinations rely on ultraviolet lines (e.g., B from B I lines). The new data complement and, for the species in common, supersede a previous collection of model atoms originally designed for use in studies of early-type stars. C1 Univ Texas, McDonald Observ, Austin, TX 78712 USA. Univ Texas, Dept Astron, Austin, TX 78712 USA. NASA, Astron & Solar Phys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Prieto, CA (reprint author), Univ Texas, McDonald Observ, RLM 15-308, Austin, TX 78712 USA. NR 29 TC 26 Z9 26 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 AUG PY 2003 VL 147 IS 2 BP 363 EP 368 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 704BY UT WOS:000184318900005 ER PT J AU Bhatia, AK Landi, E AF Bhatia, AK Landi, E TI Atomic data and spectral line intensities for S x SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article DE atomic data; plasmas ID EXTREME-ULTRAVIOLET SPECTRUM; NITROGEN ISOELECTRONIC SEQUENCE; ELECTRON-IMPACT EXCITATION; HIGHLY IONIZED SULFUR; SOLAR ACTIVE-REGION; N = 2; EMISSION-LINES; COLLISION STRENGTHS; RESONANCE LINES; OSCILLATOR-STRENGTHS AB Electron impact collision strengths, energy levels, oscillator strengths and spontaneous radiative decay rates are calculated for S x. The configurations included are 2s(2)2p(3), 2s2p(4), 2p(5), 2s(2)2p(2)3s, 2s(2)2p(2)3p, and 2s(2)2p(2)3d giving rise to 72 fine-structure levels in intermediate coupling. Collision strengths are calculated at five incident energies, 25, 50, 75, 100, and 125 ryd. 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, statistical equilibrium equations for level populations are solved. Proton excitation rates between the levels of the ground configuration have also been calculated and included in the statistical equilibrium equations. The predicted S x line intensities are compared with SUMER observations of the quiet Sun. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Artep Inc, Ellicott City, MD USA. USN, Res Lab, Washington, DC 20375 USA. RP Bhatia, AK (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RI Landi, Enrico/H-4493-2011 NR 51 TC 14 Z9 14 U1 0 U2 6 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 AUG PY 2003 VL 147 IS 2 BP 409 EP 419 DI 10.1086/375721 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 704BY UT WOS:000184318900009 ER PT J AU Ueno, T Ballard, RE Macias, BR Yost, WT Hargens, AR AF Ueno, T Ballard, RE Macias, BR Yost, WT Hargens, AR TI Cranial diameter pulsations measured by non-invasive ultrasound decrease with tilt SO AVIATION SPACE AND ENVIRONMENTAL MEDICINE LA English DT Article DE ultrasound; pulsed phase lock loop; postural change; intracranial pressure ID INTRACRANIAL-PRESSURE AB Introduction: Intracranial pressure (ICP) may play a significant role in physiological responses to microgravity by contributing to the nausea associated with microgravity exposure. However, effects of altered gravity on ICP in astronauts have not been investigated, primarily due to the invasiveness of currently available techniques. We have developed an ultrasonic device that monitors changes in cranial diameter pulsation non-invasively so that we can evaluate ICP dynamics in astronauts during spaceflight. This study was designed to demonstrate the feasibility of our ultrasound technique under the physiological condition in which ICP dynamics are changed due to altered gravitational force. Methods: Six healthy volunteers were placed at 60 head-up, 30degrees head-up, supine, and 15degrees head-down positions for 3 min at each angle. We measured arterial blood pressure (ABP) with a finger pressure cuff, and cranial diameter pulsation with a pulsed phase lock loop device (PPLL). Results: Analysis of covariance demonstrated that amplitudes of cranial diameter pulsations were significantly altered with the angle of tilt (p < 0.001). The 95% confidence interval for linear regression coefficients of the cranial diameter pulsation amplitudes with tilt angle was 0.862 to 0.968. However, ABP amplitudes did not show this relationship. Discussion: Our noninvasive ultrasonic technique reveals that the amplitude of cranial diameter pulsation decreases as a function of tilt angle, suggesting that ICP pulsation follows the same relationship. It is demonstrated that the PPLL device has a sufficient sensitivity to detect changes non-invasively in ICP pulsation caused by altered gravity. C1 NASA, Ames Res Ctr, Div Life Sci, Gravitat Res Branch, Moffett Field, CA 94035 USA. RP Ueno, T (reprint author), Univ Calif San Diego, Med Ctr, 350 Dickinson St,MC 8894, San Diego, CA 92103 USA. NR 12 TC 13 Z9 13 U1 0 U2 3 PU AEROSPACE MEDICAL ASSOC PI ALEXANDRIA PA 320 S HENRY ST, ALEXANDRIA, VA 22314-3579 USA SN 0095-6562 J9 AVIAT SPACE ENVIR MD JI Aviat. Space Environ. Med. PD AUG PY 2003 VL 74 IS 8 BP 882 EP 885 PG 4 WC Public, Environmental & Occupational Health; Medicine, General & Internal; Sport Sciences SC Public, Environmental & Occupational Health; General & Internal Medicine; Sport Sciences GA 706WV UT WOS:000184478800014 PM 12924766 ER PT J AU Dai, YJ Zeng, XB Dickinson, RE Baker, I Bonan, GB Bosilovich, MG Denning, AS Dirmeyer, PA Houser, PR Niu, GY Oleson, KW Schlosser, CA Yang, ZL AF Dai, YJ Zeng, XB Dickinson, RE Baker, I Bonan, GB Bosilovich, MG Denning, AS Dirmeyer, PA Houser, PR Niu, GY Oleson, KW Schlosser, CA Yang, ZL TI The Common Land Model SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article ID SOIL-MOISTURE; PROJECT; CLIMATE; SCHEMES; PHASE; PILPS; SIMULATIONS; HYDROLOGY; VALDAI; RUSSIA AB Scientists from several institutions and with different research backgrounds have worked together to develop a prototype modular land model for weather forecasting and climate studies. This model is now available for public sue and further development. C1 Georgia Inst Technol, Sch Earth & Atmospher Sci, Atlanta, GA 30332 USA. Univ Arizona, Dept Atmospher Sci, Tucson, AZ USA. Colorado State Univ, Dept Atmospher Sci, Ft Collins, CO 80523 USA. Natl Ctr Atmospher Res, Boulder, CO 80307 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Ctr Ocean Land Atmosphere Studiest, Galverton, MD USA. Univ Texas, Dept Geol Sci, Austin, TX USA. RP Georgia Inst Technol, Sch Earth & Atmospher Sci, 311 Ferst Dr, Atlanta, GA 30332 USA. EM dai@eas.gatech.edu RI Oleson, Keith/A-9328-2008; Dai, Yongjiu/D-1070-2010; Yang, Zong-Liang/B-4916-2011; Bosilovich, Michael/F-8175-2012; Denning, Scott/F-4974-2011; Houser, Paul/J-9515-2013; Dirmeyer, Paul/B-6553-2016; Niu, Guo-Yue/B-8317-2011; Dai, Yongjiu/D-6261-2014 OI Zeng, Xubin/0000-0001-7352-2764; Denning, Scott/0000-0003-3032-7875; Houser, Paul/0000-0002-2991-0441; Dirmeyer, Paul/0000-0003-3158-1752; Dai, Yongjiu/0000-0002-3588-6644 NR 34 TC 518 Z9 644 U1 5 U2 63 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 AUG PY 2003 VL 84 IS 8 BP 1013 EP 1023 DI 10.1175/BAMS-84-8-1013 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 712ZJ UT WOS:000184829200015 ER PT J AU Tao, WK Starr, D Hou, A Newman, P Sud, Y AF Tao, WK Starr, D Hou, A Newman, P Sud, Y TI A cumulus parameterization workshop SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Editorial Material AB A group of cloud modelers, large-scale modelers, observationalists, and parameterization developers have discussed the past, current, and future research and applications for cumulus parameterization. C1 NASA, Goddard Space Flight Ctr, Mesoscale Atmospher Proc Branch, Atmospheres Lab, Greenbelt, MD 20771 USA. RP Tao, WK (reprint author), NASA, Goddard Space Flight Ctr, Mesoscale Atmospher Proc Branch, Atmospheres Lab, Code 912, Greenbelt, MD 20771 USA. RI Newman, Paul/D-6208-2012; Hou, Arthur/D-8578-2012 OI Newman, Paul/0000-0003-1139-2508; NR 0 TC 12 Z9 13 U1 0 U2 0 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 AUG PY 2003 VL 84 IS 8 BP 1055 EP + DI 10.1175/BAMS-84-8-1055 PG 10 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 712ZJ UT WOS:000184829200019 ER PT J AU Pipes, RB Frankland, SJV Hubert, P Saether, E AF Pipes, RB Frankland, SJV Hubert, P Saether, E TI Self-consistent properties of carbon nanotubes and hexagonal arrays as composite reinforcements SO COMPOSITES SCIENCE AND TECHNOLOGY LA English DT Article DE single wall carbon nanotubes ID ELASTIC PROPERTIES; VIBRATIONAL PROPERTIES; ROPES; MODULUS AB A self-consistent set of relationships is developed for the physical properties of single walled carbon nanotubes (SWCN) and their hexagonal arrays as a function of the chiral vector integer pair, (n,m). Properties include effective radius, density, principal Young's modulus, and specific Young's modulus. Relationships between weight fraction and volume fraction of SWCN and their arrays are developed for the full range of polymeric mixtures. Examples are presented for various values of polymer density and for multiple SWCN diameters. (C) 2003 Elsevier Science Ltd. All rights reserved. C1 Univ Akron, Polymer Engn Acad Ctr, Akron, OH 44325 USA. NASA, ICASE, Langley Res Ctr, Hampton, VA 23681 USA. McGill Univ, Montreal, PQ H3A 2K6, Canada. RP Pipes, RB (reprint author), Univ Akron, Polymer Engn Acad Ctr, Akron, OH 44325 USA. NR 21 TC 48 Z9 49 U1 1 U2 7 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0266-3538 J9 COMPOS SCI TECHNOL JI Compos. Sci. Technol. PD AUG PY 2003 VL 63 IS 10 BP 1349 EP 1358 DI 10.1016/S0266-3538(03)00020-4 PG 10 WC Materials Science, Composites SC Materials Science GA 693VD UT WOS:000183738300002 ER PT J AU Gates, TS AF Gates, TS TI Special issue - Modeling and characterization of nanostructured materials SO COMPOSITES SCIENCE AND TECHNOLOGY LA English DT Editorial Material C1 NASA, Langley Res Ctr, Hampton, VA 23665 USA. RP Gates, TS (reprint author), NASA, Langley Res Ctr, MS 188E 2 W Reid St, Hampton, VA 23665 USA. NR 0 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 0266-3538 J9 COMPOS SCI TECHNOL JI Compos. Sci. Technol. PD AUG PY 2003 VL 63 IS 11 BP 1497 EP 1498 DI 10.1016/S0266-3538(03)00053-8 PG 2 WC Materials Science, Composites SC Materials Science GA 701KT UT WOS:000184167300001 ER PT J AU Saether, E Frankland, SJV Pipes, RB AF Saether, E Frankland, SJV Pipes, RB TI Transverse mechanical properties of single-walled carbon nanotube crystals. Part I: determination of elastic moduli SO COMPOSITES SCIENCE AND TECHNOLOGY LA English DT Article DE mechanical properties; composites; carbon nanotubes; bundles ID ROPES AB Carbon nanotubes naturally tend to form crystals in the form of hexagonally packed bundles. An accurate determination of the effective mechanical properties of nanotube bundles is important in order to assess potential structural applications such as reinforcement in future composite material systems. Although the intratube axial stiffness is on the order of 1 TPa due to a strong network of carbon-carbon bonds, the intertube interactions are controlled by weaker, nonbonding van der Waals forces which are orders of magnitude less. A direct method for calculating effective material constants is implemented in the present study. The Lennard-Jones potential is used to model the nonbonding cohesive forces. A complete set of transverse moduli is obtained and shown to exhibit a transversely isotropic constitutive behavior. The predicted elastic constants obtained using the direct method are compared with available published results obtained from other methods. Published by Elsevier Ltd. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. NASA, Langley Res Ctr, Natl Inst Aerosp, Hampton, VA 23666 USA. Univ Akron, Akron, OH 44325 USA. RP Saether, E (reprint author), NASA, Langley Res Ctr, MS 240, Hampton, VA 23681 USA. NR 26 TC 65 Z9 65 U1 1 U2 11 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0266-3538 J9 COMPOS SCI TECHNOL JI Compos. Sci. Technol. PD AUG PY 2003 VL 63 IS 11 BP 1543 EP 1550 DI 10.1016/S0266-3538(03)00056-3 PG 8 WC Materials Science, Composites SC Materials Science GA 701KT UT WOS:000184167300007 ER PT J AU Saether, E AF Saether, E TI Transverse mechanical properties of carbon nanotube crystals. Part II: sensitivity to lattice distortions SO COMPOSITES SCIENCE AND TECHNOLOGY LA English DT Article DE mechanical properties; carbon nanotubes; bundles; composites; probabilistic methods ID ELASTIC PROPERTIES; MODULI; ROPES AB Perfect crystals of carbon nanotubes tend to form aligned bundles that assume a hexagonal packing configuration in a minimum energy state. The theoretical constitutive relation for these defect-free crystals is highly anisotropic with a large axial stiffness due to a network of strong delocalized carbon-carbon bonds and transverse properties that are orders of magnitude lower due to a sole dependence on non-bonding van der Waals forces. The assemblage of a large number of collimated nanotubes may be expected to exhibit a distribution of lattice sites containing imperfections caused by packing faults or inclusions that will function as 'weak-links' and adversely affect local stiffness and strength. The present study is therefore directed towards quantifying the effects of distorted bundle configurations on mechanical properties. To illustrate distortion sensitivity, the transverse shear and bulk moduli are calculated by considering various magnitudes of random perturbations in nanotube packing. Monte Carlo simulations are performed to obtain a statistical distribution of predicted moduli. The present analysis demonstrates that even small perturbations to the lattice geometry give rise to large variations in transverse moduli, and suggests that chemical functionalization to improve nanotube bundle cohesion may be required for successful structural applications. Published by Elsevier Ltd. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Saether, E (reprint author), NASA, Langley Res Ctr, MS 240, Hampton, VA 23681 USA. NR 13 TC 8 Z9 8 U1 0 U2 6 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0266-3538 J9 COMPOS SCI TECHNOL JI Compos. Sci. Technol. PD AUG PY 2003 VL 63 IS 11 BP 1551 EP 1559 DI 10.1016/S0266-3538(03)00057-5 PG 9 WC Materials Science, Composites SC Materials Science GA 701KT UT WOS:000184167300008 ER PT J AU Wang, YQ Sun, CJ Sun, XK Hinkley, J Odegard, GM Gates, TS AF Wang, YQ Sun, CJ Sun, XK Hinkley, J Odegard, GM Gates, TS TI 2-D nano-scale finite element analysis of a polymer field SO COMPOSITES SCIENCE AND TECHNOLOGY LA English DT Article DE polymer; finite element analysis; molecular mechanics; nano-scale analysis ID WALLED CARBON NANOTUBES; STRESS-STRAIN BEHAVIOR; MOLECULAR-DYNAMICS; AMORPHOUS POLYMER; DEFORMATION AB Two types of 2-D nano-scale finite elements, the chemical bond element and the Lennard-Jones element, are formulated based upon inter-atomic and inter-molecular force fields. A nano-scale finite element method is employed to simulate polymer field deformation. This numerical procedure includes three steps. First, a polymer field is created by an off-lattice random walk, followed by a force relaxation process. Then, a finite element mesh is generated for the polymer field. Chemical bonds are modeled by chemical bond elements. If the distance between two non-bonded atoms or monomers is shorter than the action range of the Lennard-Jones attraction (or repulsion), a Lennard-Jones element is inserted between them. Finally, external load and boundary conditions are applied and polymer chain deformation is simulated step by step. During polymer deformation, failed Lennard-Jones bond elements are removed and newly formed Lennard-Jones elements are inserted into the polymer field during each loading step. The process continues until failure occurs. Two examples are presented to demonstrate the process. Stress-strain curves of polymer fields under unidirectional tensile load are derived. Continuum mechanical properties, such as modulus and polymer strength, are determined based upon the stress strain curve. Further, throughout the deformation process one observes polymer chain migration, nano-scale void generation, void coalescence and crack development. (C) 2003 Published by Elsevier Ltd. C1 Kansas State Univ, Dept Mech & Nucl Engn, Manhattan, KS 66506 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Wang, YQ (reprint author), Kansas State Univ, Dept Mech & Nucl Engn, Manhattan, KS 66506 USA. NR 20 TC 27 Z9 27 U1 0 U2 4 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0266-3538 J9 COMPOS SCI TECHNOL JI Compos. Sci. Technol. PD AUG PY 2003 VL 63 IS 11 BP 1581 EP 1590 DI 10.1016/S0266-3538(03)00068-X PG 10 WC Materials Science, Composites SC Materials Science GA 701KT UT WOS:000184167300011 ER PT J AU Thompson, CM Herring, HM Gates, TS Connell, JW AF Thompson, CM Herring, HM Gates, TS Connell, JW TI Preparation and characterization of metal oxide/polyimide nanocomposites SO COMPOSITES SCIENCE AND TECHNOLOGY LA English DT Article DE space environmentally durable polyimides; nanocomposites; metal oxides ID DISPLAYS AB In an effort to introduce low levels of electrical conductivity into space durable polyimides while maintaining optical clarity, nanocomposites containing metal oxides were prepared and characterized. Polymeric materials that exhibit space environmental durability, high optical transmission, low solar absorptivity and sufficient electrical conductivity for electrostatic charge dissipation are needed for future ultra-lightweight, deployable spacecraft. Samples were prepared by the addition of the metal oxide to a pre-made polyimide solution and by the synthesis of the polyimide in the presence of the metal oxide. Sonication was used to aid in the dispersion of the metal oxide particles in N,N'-dimethylacetamide prior to mixing. Thin films were prepared and characterized for thermal and mechanical properties, solar absorptivity, thermal emissivity, electrical conductivity, optical transmission and degree of dispersion of the metal oxide particles. The effect of the metal oxide particles on the polyimide properties will be discussed. Published by Elsevier Ltd. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Thompson, CM (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 15 TC 18 Z9 20 U1 1 U2 6 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0266-3538 J9 COMPOS SCI TECHNOL JI Compos. Sci. Technol. PD AUG PY 2003 VL 63 IS 11 BP 1591 EP 1598 DI 10.1016/S0266-3538(03)00062-9 PG 8 WC Materials Science, Composites SC Materials Science GA 701KT UT WOS:000184167300012 ER PT J AU Ounaies, Z Park, C Wise, KE Siochi, EJ Harrison, JS AF Ounaies, Z Park, C Wise, KE Siochi, EJ Harrison, JS TI Electrical properties of single wall carbon nanotube reinforced polyimide composites SO COMPOSITES SCIENCE AND TECHNOLOGY LA English DT Article DE nanostructures; polymers; electrical properties; modelling; single wall carbon nanotube; composites ID CONTINUUM PERCOLATION; POLYMER COMPOSITES; RESISTIVITY; DISPERSION; STICKS; VOLUME AB Electrical properties of single wall carbon nanotube (SWNT) reinforced polyimide composites were investigated as a function of SWNT concentration. AC and DC conductivities were measured, and the frequency behavior of the specific admittance was investigated. The experimental conductivity was found to obey a percolation-like power law with a relatively low percolation threshold. The current-voltage measurement results exhibited a non-ohmic behavior, indicating a quantum tunneling conduction mechanism. Analytical modeling and numerical simulation using high aspect ratio, rigid, spherocylinders as models for the SWNT were carried out to aid in understanding these results. The predictions were in good agreement with the experimental results. Published by Elsevier Ltd. C1 Virginia Commonwealth Univ, Dept Engn Mech, Richmond, VA 23284 USA. NASA, Langley Res Ctr, ICASE, Hampton, VA 23681 USA. RP Ounaies, Z (reprint author), Virginia Commonwealth Univ, Dept Engn Mech, Med Coll Virginia Campus, Richmond, VA 23284 USA. NR 25 TC 407 Z9 424 U1 15 U2 110 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0266-3538 J9 COMPOS SCI TECHNOL JI Compos. Sci. Technol. PD AUG PY 2003 VL 63 IS 11 BP 1637 EP 1646 DI 10.1016/S0266-3538(03)00067-8 PG 10 WC Materials Science, Composites SC Materials Science GA 701KT UT WOS:000184167300017 ER PT J AU Frankland, SJV Harik, VM Odegard, GM Brenner, DW Gates, TS AF Frankland, SJV Harik, VM Odegard, GM Brenner, DW Gates, TS TI The stress-strain behavior of polymer-nanotube composites from molecular dynamics simulation SO COMPOSITES SCIENCE AND TECHNOLOGY LA English DT Article DE polymer-matrix composites (PMCs); mechanical properties; stress/strain curves; computational simulation; carbon nanotubes ID WALLED CARBON NANOTUBES; ELASTIC PROPERTIES; LOAD-TRANSFER; DEFORMATION; MECHANICS; STRENGTH; MATRIX AB Stress-strain curves of polymer-carbon nanotube composites generated from molecular dynamics simulations of a single-walled carbon nanotube embedded in polyethylene are presented. A comparison is made between the response to mechanical loading of a composite with a long, continuous nanotube (replicated via periodic boundary conditions) and the response of a composite with a short, discontinuous nanotube. Both composites are mechanically loaded in the direction of, and transverse to, the nanotube axis. The long-nanotube composite shows an increase in the stiffness relative to the polymer and behaves anisotropically under the different loading conditions considered. The short-nanotube composite shows no enhancement relative to the polymer, most probably because of its low aspect ratio. The stress-strain curves from molecular dynamics simulations are compared with corresponding rule-of-mixtures predictions. Published by Elsevier Ltd. C1 Natl Inst Aerosp, Hampton, VA 23666 USA. NASA, Langley Res Ctr, Swales Aerosp, Hampton, VA 23681 USA. N Carolina State Univ, Dept Mat Sci & Engn, Raleigh, NC 27695 USA. NASA, Langley Res Ctr, Mech & Durabil Branch, Hampton, VA 23681 USA. RP Frankland, SJV (reprint author), Natl Inst Aerosp, 144 Res Dr, Hampton, VA 23666 USA. RI Brenner, Donald/D-1741-2009 NR 34 TC 251 Z9 255 U1 3 U2 63 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0266-3538 J9 COMPOS SCI TECHNOL JI Compos. Sci. Technol. PD AUG PY 2003 VL 63 IS 11 BP 1655 EP 1661 DI 10.1016/S0266-3538(03)00059-9 PG 7 WC Materials Science, Composites SC Materials Science GA 701KT UT WOS:000184167300019 ER PT J AU Odegard, GM Gates, TS Wise, KE Park, C Siochi, EJ AF Odegard, GM Gates, TS Wise, KE Park, C Siochi, EJ TI Constitutive modeling of nanotube-reinforced polymer composites SO COMPOSITES SCIENCE AND TECHNOLOGY LA English DT Article DE mechanical properties; modelling; anisotropy; carbon nanotubes; nanotechnology ID MM3 FORCE-FIELD; WALLED CARBON NANOTUBES; MOLECULAR-MECHANICS; AROMATIC-HYDROCARBONS; POLYIMIDE; WEIGHT; ENERGY; WATER AB In this study, a technique is presented for developing constitutive models for polymer composite systems reinforced with single-walled carbon nanotubes (SWNT). Because the polymer molecules are on the same size scale as the nanotubes, the interaction at the polymer/nanotube interface is highly dependent on the local molecular structure and bonding. At these small length scales, the lattice structures of the nanotube and polymer chains cannot be considered continuous, and the bulk mechanical properties can no longer be determined through traditional micromechanical approaches that are formulated by using continuum mechanics. It is proposed herein that the nanotube, the local polymer near the nanotube, and the nanotube/polymer interface can be modeled as an effective continuum fiber by using an equivalent-continuum modeling method. The effective fiber serves as a means for incorporating micromechanical analyses for the prediction of bulk mechanical properties of SWNT/polymer composites with various nanotube lengths, concentrations, and orientations. As an example, the proposed approach is used for the constitutive modeling of two SWNT/polyimide composite systems. Published by Elsevier Ltd. C1 NASA, Langley Res Ctr, Natl Inst Aerosp, Hampton, VA 23681 USA. RP Odegard, GM (reprint author), NASA, Langley Res Ctr, Natl Inst Aerosp, MS 390, Hampton, VA 23681 USA. EM g.m.odegard@larc.nasa.gov OI Odegard, Gregory/0000-0001-7577-6565 NR 41 TC 395 Z9 408 U1 3 U2 76 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0266-3538 J9 COMPOS SCI TECHNOL JI Compos. Sci. Technol. PD AUG PY 2003 VL 63 IS 11 BP 1671 EP 1687 DI 10.1016/S0266-3538(03)00063-0 PG 17 WC Materials Science, Composites SC Materials Science GA 701KT UT WOS:000184167300021 ER PT J AU Rubinstein, R Zhou, Y AF Rubinstein, R Zhou, Y TI Schiestel's derivation of the Epsilon equation and two-equation modelling of rotating turbulence SO COMPUTERS & MATHEMATICS WITH APPLICATIONS LA English DT Article DE dissipation rate equation; rotating turbulence; two-equation turbulence models; multiple-scale turbulence models ID COMPUTATION; FLOWS AB As part of a more general program of developing multiple-scale models of turbulence, Schiestel suggested a derivation of the homogeneous part of the dissipation rate transport equation. Schiestel's approach is generalized to rotating turbulence. The resulting model reproduces the main features observed in decaying rotating turbulence. (C) 2003 Elsevier Ltd. All rights reserved. C1 NASA, Langley Res Ctr, ICASE, Hampton, VA 23681 USA. Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Rubinstein, R (reprint author), NASA, Langley Res Ctr, ICASE, Hampton, VA 23681 USA. NR 11 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 0898-1221 J9 COMPUT MATH APPL JI Comput. Math. Appl. PD AUG PY 2003 VL 46 IS 4 BP 633 EP 638 DI 10.1016/S0898-1221(03)00247-5 PG 6 WC Computer Science, Interdisciplinary Applications; Mathematics, Applied SC Computer Science; Mathematics GA 724RB UT WOS:000185499600009 ER PT J AU Singer, BA Lockard, DP Lilley, GM AF Singer, BA Lockard, DP Lilley, GM TI Hybrid acoustic predictions SO COMPUTERS & MATHEMATICS WITH APPLICATIONS LA English DT Article DE computational aeroacoustics; CAA; noise; sound; acoustics ID BOUNDARY-CONDITIONS; TRAILING-EDGE; AERODYNAMIC SOUND; NOISE; COMPUTATION; VORTEX; SIMULATIONS; SCATTERING; GENERATION; RADIATION AB Hybrid acoustic prediction combines the use of unsteady computational fluid dynamics for calculating the properties of acoustic sources with some form of Lighthill's acoustic analogy to calculate the resulting far-field noise radiation. This approach avoids some of the difficult issues involved in computing both the acoustic sources and the acoustic propagation in a single computation. However, hybrid acoustic prediction still faces numerous uncertainties associated with the computation of the properties of the acoustic sources, and the coupling of the noise-source computation with the acoustic propagation computation. Several of these uncertainties are discussed, including examples where some of the issues have been successfully resolved. (C) 2003 Elsevier Ltd. All rights reserved. C1 NASA, Langley Res Ctr, Computat Modelling & Simulat Branch, Hampton, VA 23681 USA. Univ Southampton, Southampton, Hants, England. RP Singer, BA (reprint author), NASA, Langley Res Ctr, Computat Modelling & Simulat Branch, Hampton, VA 23681 USA. NR 49 TC 10 Z9 11 U1 0 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0898-1221 J9 COMPUT MATH APPL JI Comput. Math. Appl. PD AUG PY 2003 VL 46 IS 4 BP 647 EP 669 DI 10.1016/S0898-1221(03)00249-9 PG 23 WC Mathematics, Applied SC Mathematics GA 724RB UT WOS:000185499600011 ER PT J AU Yang, JN Lei, Y Pan, SW Huang, N AF Yang, JN Lei, Y Pan, SW Huang, N TI System identification of linear structures based on Hilbert-Huang spectral analysis. Part 2: Complex modes SO EARTHQUAKE ENGINEERING & STRUCTURAL DYNAMICS LA English DT Article DE system identification; Hilbert transform; linear structures; complex modes; data analysis; Hilbert-Huang spectral analysis ID TRANSFORM AB A method, based on the Hilbert-Huang spectral analysis, has been proposed by the authors to identify linear structures in which normal modes exist (i.e., real eigenvalues and eigenvectors). Frequently, all the eigenvalues and eigenvectors of linear structures are complex. In this paper, the method is extended further to identify general linear structures with complex modes using the free vibration response data polluted by noise. Measured response signals are first decomposed into modal responses using the method of Empirical Mode Decomposition with intermittency criteria. Each modal response contains the contribution of a complex conjugate pair of modes with a unique frequency and a damping ratio. Then, each modal response is decomposed in the frequency-time domain to yield instantaneous phase angle and amplitude using the Hilbert transform. Based on a single measurement of the impulse response time history at one appropriate location, the complex eigenvalues of the linear structure can be identified using a simple analysis procedure. When the response time histories are measured at all locations, the proposed methodology is capable of identifying the complex mode shapes as well as the mass, damping and stiffness matrices of the structure. The effectiveness and accuracy of the method presented are illustrated through numerical simulations. It is demonstrated that dynamic characteristics of linear structures with complex modes can be identified effectively using the proposed method. Copyright (C) 2003 John Wiley Sons, Ltd. C1 Univ Calif Irvine, Dept Civil & Environm Engn, Irvine, CA 92697 USA. NASA, Goddard Space Flight Ctr, Lab Hydrospher Proc, Greenbelt, MD 20771 USA. RP Yang, JN (reprint author), Univ Calif Irvine, Dept Civil & Environm Engn, Irvine, CA 92697 USA. RI Lei, ying/C-8567-2013 NR 11 TC 77 Z9 102 U1 1 U2 21 PU JOHN WILEY & SONS LTD PI CHICHESTER PA THE ATRIUM, SOUTHERN GATE, CHICHESTER PO19 8SQ, W SUSSEX, ENGLAND SN 0098-8847 J9 EARTHQUAKE ENG STRUC JI Earthq. Eng. Struct. Dyn. PD AUG PY 2003 VL 32 IS 10 BP 1533 EP 1554 DI 10.1002/eqe.288 PG 22 WC Engineering, Civil; Engineering, Geological SC Engineering GA 708AY UT WOS:000184545300003 ER PT J AU Kramer, MG Sollins, P Sletten, RS Swart, PK AF Kramer, MG Sollins, P Sletten, RS Swart, PK TI N isotope fractionation and measures of organic matter alteration during decomposition SO ECOLOGY LA English DT Article DE decomposition; humification; illuviation; isotope fractionation; natural (15)N and (11)C isotope abundance; soil organic carbon; soil organic matter dynamics; (13)C solid-state nuclear magnetic resonance (NMR) ID N-15 NATURAL-ABUNDANCE; FOREST SOIL; CARBON; NITROGEN AB Most soil organic matter (SOM) derives from plant material, but there are substantial gaps in our understanding of its transformation mechanisms. Alterations that occur as SOM decays and is stabilized have proved difficult to study owing largely to its diverse initial chemical composition and stable isotope values. We examined SOM stable isotope ratios in relation to composition using solid-state (13)C Cross Polarization Magic Angle Spin (CPMAS) nuclear magnetic resonance (NMR) in sequentially deeper organic and mineral horizon soil samples collected from an unpolluted ecosystem in southeast Alaska, USA, dominated by C(3) vegetation. We found that, as humified carbon (C not respired as CO, during decomposition) increased in aliphaticity (ratio of unsubstituted aliphatics to carbohydrates), it also increased in (15)N but showed no clear trend in (13)C. These results imply that humification (and the concomitant stabilization of soil C) at our site resulted from microbial alteration of organics rather than from accumulation of recalcitrant compounds. The strong, and previously unreported, relation between (15)N and SOM composition found at our study site suggests that degree of SOM humification may be correlated with an increase in delta(15)N SOM values relative to delta(15)N for fresh litter and other source material. C1 NASA, Ames Res Ctr, Ecosyst Sci & Technol Branch, Div Earth Sci, Moffett Field, CA 94035 USA. Oregon State Univ, Coll Forestry, Dept Forest Sci, Corvallis, OR 97331 USA. Univ Washington, Dept Geol Sci, Seattle, WA 98195 USA. Univ Miami, Rosenstiel Sch Marine & Atmospher Sci, Miami, FL 33149 USA. RP Kramer, MG (reprint author), NASA, Ames Res Ctr, Ecosyst Sci & Technol Branch, Div Earth Sci, Mail Stop 242-4, Moffett Field, CA 94035 USA. RI Swart, Peter/K-7041-2016 NR 24 TC 116 Z9 117 U1 5 U2 51 PU ECOLOGICAL SOC AMER PI WASHINGTON PA 1990 M STREET NW, STE 700, WASHINGTON, DC 20036 USA SN 0012-9658 J9 ECOLOGY JI Ecology PD AUG PY 2003 VL 84 IS 8 BP 2021 EP 2025 DI 10.1890/02-3097 PG 5 WC Ecology SC Environmental Sciences & Ecology GA 717EQ UT WOS:000185073100009 ER PT J AU Rowan, LC Hook, SJ Abrams, MJ Mars, JC AF Rowan, LC Hook, SJ Abrams, MJ Mars, JC TI Mapping hydrothermally altered rocks at Cuprite, Nevada, using the advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), a new satellite-imaging system SO ECONOMIC GEOLOGY AND THE BULLETIN OF THE SOCIETY OF ECONOMIC GEOLOGISTS LA English DT Article ID SCANNER IMAGES; SPECTROMETER; PERFORMANCE; IR AB The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) is a 14-band multispectral instrument on board the Earth Observing System (EOS), TERRA. The three bands between 0.52 and 0.86 mum and the six bands from 1.60 and 2.43 mum, which have 15- and 30-m spatial resolution, respectively, were selected primarily for making remote mineralogical determinations. The Cuprite, Nevada, mining district comprises two hydrothermal alteration centers where Tertiary volcanic rocks have been hydrothermally altered mainly to bleached silicified rocks and opalized rocks, with a marginal zone of limonitic argillized rocks. Country rocks are mainly Cambrian phyllitic siltstone and limestone. Evaluation of an ASTER image of the Cuprite district shows that spectral reflectance differences in the nine bands in the 0.52 to 2.43 mum region provide a basis for identifying and mapping mineralogical components which characterize the main hydrothermal alteration zones: opal is the spectrally dominant mineral in the silicified zone; whereas, alunite and kaolinite are dominant in the opalized zone. In addition, the distribution of unaltered country rocks was mapped because of the presence of spectrally dominant muscovite in the siltstone and calcite in limestone, and the tuffaceous rocks and playa deposits were distinguishable due to their relatively flat spectra and weak absorption features at 2.33 and 2.20 mum, respectively. An Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) image of the study area was processed using a similar methodology used with the ASTER data. Comparison of the ASTER and AVIRIS results shows that the results are generally similar, but the higher spectral resolution of AVIRIS (224 bands) permits identification of more individual minerals, including certain polymorphs. However, ASTER has recorded images of more than 90 percent of the Earth's land surface with less than 20 percent cloud cover, and these data are available at nominal or no cost. Landsat TM images have a similar spatial resolution to ASTER images, but TM has fewer bands, which limits its usefulness for making mineral determinations. C1 US Geol Survey, Reston, VA USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Rowan, LC (reprint author), US Geol Survey, Mail Stop 954, Reston, VA USA. NR 29 TC 94 Z9 102 U1 2 U2 14 PU ECONOMIC GEOLOGY PUBL CO PI LITTLETON PA 5808 SOUTH RAPP ST, STE 209, LITTLETON, CO 80120-1942 USA SN 0361-0128 J9 ECON GEOL BULL SOC JI Econ. Geol. Bull. Soc. Econ. Geol. PD AUG PY 2003 VL 98 IS 5 BP 1019 EP 1027 DI 10.2113/98.5.1019 PG 9 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 708UR UT WOS:000184588400009 ER PT J AU Koken, PJM Piver, WT Ye, F Elixhauser, A Olsen, LM Portier, CJ AF Koken, PJM Piver, WT Ye, F Elixhauser, A Olsen, LM Portier, CJ TI Temperature, air pollution, and hospitalization for cardiovascular diseases among elderly people in Denver SO ENVIRONMENTAL HEALTH PERSPECTIVES LA English DT Article DE acute myocardial infarction; air pollution; cardiac dysrhythmias; cardiovascular diseases; CO; congestive heart failure; coronary atherosclerosis; generalized estimating equations; NO2; O-3; PM10; Poisson regression; pulmonary heart disease; SO2; temperature ID CONGESTIVE-HEART-FAILURE; TIME-SERIES ANALYSIS; CARBON-MONOXIDE; US CITIES; ADMISSIONS; MORTALITY; ASSOCIATION; WEATHER; HEALTH; ARRHYTHMIA AB Daily measures of maximum temperature, particulate matter! 10 Put in aerodynamic diameter (PM10), and gaseous pollution (ozone, nitrogen dioxide, sulfur dioxide, and carbon monoxide) were collected in Denver, Colorado, in July and August between 1993 and 1997. We then compared these exposures with concurrent data on the number of daily hospital admissions for cardiovascular diseases in men and women > 65 years of age. Generalized linear models, assuming a Poisson error structure for the selected cardiovascular disease hospital admissions, were constructed to evaluate the associations with air pollution and temperature. After adjusting the admission data for yearly trends, day of-week effects, ambient maximum temperature, and dew point temperature, we studied the associations of the pollutants in single-pollutant models with lag times of 0-4 days. The results suggest that O-3 is associated with an increase in the risk of hospitalization for acute myocardial infarction, coronary atherosclerosis, and pulmonary heart disease. SO2 appears to be related to increased hospital stays for cardiac dysrhythmias, and CO is significantly associated with congestive heart failure. No association was found between particulate matter or NO2 and any of the health outcomes. Males tend to have higher numbers of hospital admissions than do females for all of the selected cardiovascular diseases, except for congestive heart failure. Higher temperatures appear to be an important factor in increasing the frequency of hospitalization for acute myocardial infarction and congestive heart failure, and are associated with a decrease in the frequency of visits for coronary atherosclerosis and pulmonary heart disease. C1 NIEHS, Res Triangle Pk, NC 27709 USA. Agcy Healthcare Res & Qual, Rockville, MD USA. NASA, Greenbelt, MD USA. RP Koken, PJM (reprint author), NIEHS, MD A3-06,POB 12233, Res Triangle Pk, NC 27709 USA. RI Portier, Christopher/A-3160-2010 OI Portier, Christopher/0000-0002-0954-0279 NR 46 TC 136 Z9 142 U1 6 U2 22 PU US DEPT HEALTH HUMAN SCIENCES PUBLIC HEALTH SCIENCE PI RES TRIANGLE PK PA NATL INST HEALTH, NATL INST ENVIRONMENTAL HEALTH SCIENCES, PO BOX 12233, RES TRIANGLE PK, NC 27709-2233 USA SN 0091-6765 J9 ENVIRON HEALTH PERSP JI Environ. Health Perspect. PD AUG PY 2003 VL 111 IS 10 BP 1312 EP 1317 DI 10.1289/ehp.5957 PG 6 WC Environmental Sciences; Public, Environmental & Occupational Health; Toxicology SC Environmental Sciences & Ecology; Public, Environmental & Occupational Health; Toxicology GA 711MX UT WOS:000184746600033 PM 12896852 ER PT J AU Pikuta, EV Hoover, RB Bej, AK Marsic, D Detkova, EN Whitman, WB Krader, P AF Pikuta, EV Hoover, RB Bej, AK Marsic, D Detkova, EN Whitman, WB Krader, P TI Tindallia californiensis sp nov., a new anaerobic, haloalkaliphilic, spore-forming acetogen isolated from Mono Lake in California SO EXTREMOPHILES LA English DT Article DE extremophile; haloalkaliphile; Mono Lake; proteolytic anaerobe; Tindallia californiensis sp nov. ID SULFUR-REDUCING BACTERIA; RENATURATION RATES; GEN. NOV.; DNA AB A novel extremely haloalkaliphilic, strictly anaerobic, acetogenic bacterium strain APO was isolated from sediments of the athalassic, meromictic, alkaline Mono Lake in California. The Gram-positive, spore-forming, slightly curved rods with sizes 0.55-0.7x1.7-3.0 mum were motile by a single laterally attached flagellum. Strain APO was mesophilic (range 10-48 degreesC, optimum of 37 degreesC); halophilic (NaCl range 1-20% (w/v) with optimum of 3-5% (w/v), and alkaliphilic (pH range 8.0-10.5, optimum 9.5). The novel isolate required sodium ions in the medium. Strain APO was an organotroph with a fermentative type of metabolism and used the substrates peptone, bacto-tryptone, casamino acid, yeast extract, l-serine, l-lysine, l-histidine, l-arginine, and pyruvate. The new isolate performed the Stickland reaction with the following amino acid pairs: proline + alanine, glycine + alanine, and tryptophan + valine. The main end product of growth was acetate. High activity of CO dehydrogenase and hydrogenase indicated the presence of a homoacetogenic, non-cycling acetyl-CoA pathway. Strain APO was resistant to kanamycin but sensitive to chloramphenicol, tetracycline, and gentamycin. The G+C content of the genomic DNA was 44.4 mol% (by HPLC method). The sequence of the 16S rRNA gene of strain APO possessed 98.2% similarity with the sequence from Tindallia magadiensis Z-7934, but the DNA-DNA hybridization value between these organisms was only 55%. On the basis of these physiological and molecular properties, strain APO is proposed to be a novel species of the genus Tindallia with the name Tindallia californiensis sp. nov., (type strain APO = ATCC BAA-393 = DSM 14871). C1 NASA, Natl Space Sci & Technol Ctr, Huntsville, AL 35805 USA. Univ Alabama, Dept Biol, Birmingham, AL 35294 USA. Univ Alabama, Dept Biol Sci, MSB, Huntsville, AL 35899 USA. Univ Alabama, Struct Biol Lab, MSB, Huntsville, AL 35899 USA. Russian Acad Sci, Inst Microbiol, Moscow 117811, Russia. Univ Georgia, Dept Microbiol, Athens, GA 30602 USA. Amer Type Culture Collect, Manassas, VA 20110 USA. RP Pikuta, EV (reprint author), NASA, Natl Space Sci & Technol Ctr, SD-50,320 Sparkman Dr, Huntsville, AL 35805 USA. RI Marsic, Damien/A-1087-2009 OI Marsic, Damien/0000-0003-0847-8095 NR 28 TC 32 Z9 32 U1 2 U2 12 PU SPRINGER-VERLAG TOKYO PI TOKYO PA 3-3-13, HONGO, BUNKYO-KU, TOKYO, 113-0033, JAPAN SN 1431-0651 J9 EXTREMOPHILES JI Extremophiles PD AUG PY 2003 VL 7 IS 4 BP 327 EP 334 DI 10.1007/s00792-003-0326-7 PG 8 WC Biochemistry & Molecular Biology; Microbiology SC Biochemistry & Molecular Biology; Microbiology GA 711UE UT WOS:000184758800009 PM 12728359 ER PT J AU Lee, CTA Brandon, AD Norman, M AF Lee, CTA Brandon, AD Norman, M TI Vanadium in peridotites as a proxy for paleo-fO(2) during partial melting: Prospects, limitations, and implications SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Article ID EASTERN PYRENEAN PERIDOTITES; ARCHEAN LITHOSPHERIC MANTLE; OVERLYING SUBDUCTION ZONES; PAPUA-NEW-GUINEA; SUB-ARC MANTLE; RE-OS ISOTOPE; OXIDATION-STATE; OXYGEN FUGACITY; REDOX STATES; CRATONIC LITHOSPHERE AB The compatibility of vanadium (V) during mantle melting is a function of oxygen fugacity (fO(2)): at high fO(2)'s. V becomes more incompatible. The prospects and limitations of using the V content of peridotites as a proxy for paleo-fO(2) at the time of melt extraction were investigated here by assessing the uncertainties in V measurements and the sensitivity of V as a function of degree of melt extracted and fO(2). V-MgO and V-Al2O3 systematics were found to be sensitive to fO(2) variations, but consideration of the uncertainties in measurements and model parameters indicates that V is sensitive only to relative A differences greater than similar to2 log units. Post-Archean oceanic mantle peridotites, as represented by abyssal peridotites and obducted massif peridotites, have V-MgO and -Al2O3 systematics that can be modeled by 1.5 GPa melting between FMQ - 3 and FMQ - 1. This is consistent with fO(2)'s of the mantle source for mid-ocean ridge basalts (MORBs) as determined by the Fe3+ activity of peridotitic minerals and basaltic glasses. Some arc-related peridotites have slightly lower V for a given degree of melting than oceanic mantle peridotites, and can be modeled by 1.5 GPa melting at fO(2)'s as high as FMQ. However, the majority of arc-related peridotites have V-MgO systematics overlapping that of oceanic mantle peridotites, suggesting that although some arc mantle may melt under slightly oxidizing conditions, most arc mantle does not. The fact that thermobarometrically determined fO(2)'s in arc peridotites and lavas can be significantly higher than that inferred from V systematics, suggests that V retains a record of the fO(2) during partial melting, whereas the activity of Fe3+ in arc peridotitic minerals and lavas reflect subsequent metasomatic overprints and magmatic differentiation/emplacement processes, respectively. Peridotites associated with middle to late Archean cratonic mantle are characterized by highly variable V-MgO systematics. Tanzanian cratonic peridotites have V systematics indistinguishable from post-Archean oceanic mantle and can be modeled by 3 GPa partial melting at similar toFMQ - 3. In contrast, many South African and Siberian cratonic peridotites have much lower V contents for a given degree of melting, suggesting at first glance that partial melting occurred at high fO(2)'s. More likely, however, their unusually low V contents for a given degree of melting may be artifacts of excess orthopyroxene, a feature that pervades many South African and Siberian peridotites but not the Tanzanian peridotites. This is indicated by the fact that the V contents of South African and Siberian peridotites are correlated with increases in SiO2 content, generating data arrays that cannot be modeled by partial melting but can instead be generated by the addition of orthopyroxene through processes unrelated to primary melt depletion. Correction for orthopyroxene addition suggests that the South African and Siberian peridotites have V-MgO systematics similar to those of Tanzanian peridotites. Thus, if the Tanzanian peridotites represent the original partial melting residues, and if the South African and Siberian peridotites have been modified by orthopyroxene addition, then there is no indication that Archean cratonic mantle formed under fO(2)'s significantly greater than that of modern oceanic mantle. Instead, the fO(2)'s inferred from the V systematics in these three cratonic peridotite suites are within range of modern oceanic mantle. This also suggests that the transition from a highly reducing mantle in equilibrium with a metallic core to the present oxidized state must have occurred by late Archean times. Copyright (C) 2003 Elsevier Ltd. C1 Rice Univ, Dept Earth Sci, Houston, TX 77251 USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. Australian Natl Univ, Res Sch Earth Sci, Canberra, ACT 0200, Australia. RP Lee, CTA (reprint author), Rice Univ, Dept Earth Sci, MS-126,POB 1892, Houston, TX 77251 USA. EM ctlee@rice.edu RI Lee, Cin-Ty/A-5469-2008 NR 77 TC 74 Z9 79 U1 4 U2 20 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0016-7037 EI 1872-9533 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD AUG PY 2003 VL 67 IS 16 BP 3045 EP 3064 DI 10.1016/S0016-7037(03)00268-0 PG 20 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 709DK UT WOS:000184609300011 ER PT J AU Dubovikov, MS AF Dubovikov, MS TI Dynamic model of mesoscale eddies SO GEOPHYSICAL AND ASTROPHYSICAL FLUID DYNAMICS LA English DT Article DE isopycnal turbulence; baroclinic instability; bolus velocity; OGCM ID TWO-DIMENSIONAL TURBULENCE; OCEAN CIRCULATION MODELS; EDDY KINETIC-ENERGY; SHEAR-DRIVEN FLOWS; 2-DIMENSIONAL TURBULENCE; PASSIVE-SCALAR; TRACER TRANSPORTS; NORTH-ATLANTIC; GULF-STREAM; MEAN FLOW AB Oceanic mesoscale eddies which are analogs of well known synoptic eddies (cyclones and anticyclones), are studied on the basis of the turbulence model originated by Dubovikov (Dubovikov, M.S., "Dynamical model of turbulent eddies", Int. J. Mod. Phys. B7 , 4631-4645 ( 1993 ).) and further developed by Canuto and Dubovikov (Canuto, V.M. and Dubovikov, M.S., "A dynamical model for turbulence: I. General formalism", Phys. Fluids 8 , 571-586 ( 1996a ) (CD96a); Canuto, V.M. and Dubovikov, M.S., "A dynamical model for turbulence: II. Sheardriven flows", Phys. Fluids 8 , 587-598 ( 1996b ) (CD96b); Canuto, V.M., Dubovikov, M.S., Cheng, Y. and Dienstfrey, A., "A dynamical model for turbulence: III. Numerical results", Phys. Fluids 8 , 599-613 ( 1996c )(CD96c); Canuto, V.M., Dubovikov, M.S. and Dienstfrey, A., "A dynamical model for turbulence: IV. Buoyancy-driven flows", Phys. Fluids 9 , 2118-2131 ( 1997a ) (CD97a); Canuto, V.M. and Dubovikov, M.S., "A dynamical model for turbulence: V. The effect of rotation", Phys. Fluids 9 , 2132-2140 ( 1997b ) (CD97b); Canuto, V.M., Dubovikov, M.S. and Wielaard, D.J., "A dynamical model for turbulence: VI. Two dimensional turbulence", Phys. Fluids 9 , 2141-2147 ( 1997c ) (CD97c); Canuto, V.M. and Dubovikov, M.S., "Physical regimes and dimensional structure of rotating turbulence", Phys. Rev. Lett . 78 , 666-669 ( 1997d ) (CD97d); Canuto, V.M., Dubovikov, M.S. and Dienstfrey, A., "Turbulent convection in a spectral model", Phys. Rev. Lett . 78 , 662-665 ( 1997e ) (CD97e); Canuto, V.M. and Dubovikov, M.S., "A new approach to turbulence", Int. J. Mod. Phys. 12 , 3121-3152 ( 1997f ) (CD97f); Canuto, V.M. and Dubovikov, M.S., "Two scaling regimes for rotating Raleigh-Benard convection", Phys. Rev. Letters 78 , 281-284, ( 1998 ) (CD98); Canuto, V.M. and Dubovikov, M.S., "A dynamical model for turbulence: VII. The five invariants for shear driven flows", Phys. Fluids 11, 659-664 ( 1999a ) (CD99a); Canuto, V.M., Dubovikov, M.S. and Yu, G., "A dynamical model for turbulence: VIII. IR and UV Reynolds stress spectra for shear driven flows", Phys. Fluids 11 , 656-677 ( 1999b ) (CD99b); Canuto, V.M., Dubovikov, M.S. and Yu, G., "A dynamical model for turbulence: IX. The Reynolds stress for shear driven flows", Phys. Fluids 11, 678-694 ( 1999c ) (CD99c).). The CD model derives from general principles and does not resort to any free parameters. Yet, it successfully describes a wide variety of quite different turbulent flows. In the present work we apply CD model to the compressible ocean. The model yields mesoscale eddies generated by the baroclinic instability. The latter, in turn, arises from the nonhorizontal orientation of the surfaces of the constant potential density (isopycnals). The obtained dynamic equations for eddy fields reduce to a vertical eigen value problem, an eigen value real part yielding an eddy radius, while an imaginary part - an eddy drift velocity. The size of the eddy is about 3 r d (where r d is the Rossby deformation radius). The eddy dynamics has the following distinctive features: ( 1 ) the large scale potential energy feeds the eddy potential energy (EPE) at scales similar to r d , ( 2 ) from r d EPE cascades to the smaller scales down to similar to l 1 determined from the condition that the spectral Rossby number ( q is two-dimensional wave number within an isopycnal surface), ( 3 ) at scales similar to l 1 EPE transforms into eddy kinetic energy (EKE) which cascades backwards to the larger scales up to similar to r d , where it transforms back into EPE, thereby closing the energy flux circulation in a wavenumber space, ( 4 ) dissipation of the eddy energy (EE) occurs at scales similar to l 1 since at those scales the fluctuating component of the vertical shear is maximal and equals to the Brunt-Vaisala frequency. The latter equality is the well known condition for generating the vertical turbulence which dissipates EE. The model enables to determine all turbulence characteristics, including the horizontal (isopycnal) diffusivity kappa h in terms of the large scale mean fields. From the typical values of the latter follow estimates for the parameters of an eddy which agree well with the observational and simulational data: , EKE . In what concerns the bolus velocity, it contains additional terms (as compared to the model of Gent and McWilliams (Gent, P.R. and McWilliams, J.C., "Isopycnal mixing in ocean circulation models", J. Phys. Oceanogr. 20 , 150-155 ( 1990 )) which result from the eddy fields advection by a mean velocity . Since the latter varies with depth, it is inevitable to differ from the eddy drift velocity that produces a shearing force eroding the eddy coherent structures and, therefore, contributing negatively to EE production. This is in contrast with the positive contribution from the GM term (which is due to the baroclinic instability). In those regions where the disruptive action is stronger, there is no eddy generation. C1 NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Columbia Univ, Ctr Climate Syst Res, New York, NY 10025 USA. RP Dubovikov, MS (reprint author), NASA, Goddard Inst Space Studies, 2880 Broadway, New York, NY 10025 USA. EM mdubovikov@giss.nasa.gov NR 56 TC 2 Z9 2 U1 1 U2 4 PU TAYLOR & FRANCIS LTD PI ABINGDON PA 4 PARK SQUARE, MILTON PARK, ABINGDON OX14 4RN, OXON, ENGLAND SN 0309-1929 J9 GEOPHYS ASTRO FLUID JI Geophys. Astrophys. Fluid Dyn. PD AUG PY 2003 VL 97 IS 4 BP 311 EP 358 DI 10.1080/0309192032000101685 PG 48 WC Astronomy & Astrophysics; Geochemistry & Geophysics; Mechanics SC Astronomy & Astrophysics; Geochemistry & Geophysics; Mechanics GA 707BM UT WOS:000184489600002 ER PT J AU Hicke, JA Asner, GP Kasischke, ES French, NHF Randerson, JT Collatz, GJ Stocks, BJ Tucker, CJ Los, SO Field, CB AF Hicke, JA Asner, GP Kasischke, ES French, NHF Randerson, JT Collatz, GJ Stocks, BJ Tucker, CJ Los, SO Field, CB TI Postfire response of North American boreal forest net primary productivity analyzed with satellite observations SO GLOBAL CHANGE BIOLOGY LA English DT Article DE boreal forest; carbon cycle; emissions; fire; NDVI; net primary productivity ID US CARBON SINK; VEGETATION INDEX; ATMOSPHERIC CO2; MODELS; FIRE; BIOSPHERE; BIOMASS; COVER; DISTURBANCE; ECOSYSTEMS AB Fire is a major disturbance in the boreal forest, and has been shown to release significant amounts of carbon (C) to the atmosphere through combustion. However, less is known about the effects on ecosystems following fire, which include reduced productivity and changes in decomposition in the decade immediately following the disturbance. In this study, we assessed the impact of fire on net primary productivity (NPP) in the North American boreal forest using a 17-year record of satellite NDVI observations at 8- km spatial resolution together with a light-use efficiency model. We identified 61 fire scars in the satellite observations using digitized fire burn perimeters from a database of large fires. We studied the postfire response of NPP by analyzing the most impacted pixel within each burned area. NPP decreased in the year following the fire by 60-260 g C m(-2) yr(-1) (30-80%). By comparing pre- and postfire observations, we estimated a mean NPP recovery period for boreal forests of about 9 years, with substantial variability among fires. We incorporated this behavior into a carbon cycle model simulation to demonstrate these effects on net ecosystem production. The disturbance resulted in a release of C to the atmosphere during the first 8 years, followed by a small, but long-lived, sink lasting 150 years. Postfire net emissions were three times as large as from a model run without changing NPP. However, only small differences in the C cycle occurred between runs after 8 years due to the rapid recovery of NPP. We conclude by discussing the effects of fire on the long-term continental trends in satellite NDVI observed across boreal North America during the 1980s and 1990s. C1 Colorado State Univ, Nat Resource Ecol Lab, Ft Collins, CO 80523 USA. Univ Maryland, Dept Geog, College Pk, MD 20742 USA. Altarum, Ann Arbor, MI 48113 USA. CALTECH, Dept Geol & Planetary Sci, Pasadena, CA 91125 USA. CALTECH, Div Engn & Appl Sci, Pasadena, CA 91125 USA. NASA, Lab Atmospher Phys, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Canadian Forest Serv, Sault Ste Marie, ON P6A 2E5, Canada. Univ Coll Swansea, Swansea SA2 8PP, W Glam, Wales. RP Hicke, JA (reprint author), Colorado State Univ, Nat Resource Ecol Lab, Ft Collins, CO 80523 USA. EM jhicke@nrel.colostate.edu RI collatz, george/D-5381-2012; Los, Sietse/G-8985-2012; Hicke, Jeff/M-9677-2013; Asner, Gregory/G-9268-2013; OI Asner, Gregory/0000-0001-7893-6421; Los, Sietse/0000-0002-1325-3555; French, Nancy/0000-0002-2389-3003 NR 45 TC 90 Z9 108 U1 3 U2 28 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 1354-1013 J9 GLOBAL CHANGE BIOL JI Glob. Change Biol. PD AUG PY 2003 VL 9 IS 8 BP 1145 EP 1157 DI 10.1046/j.1365-2486.2003.00658.x PG 13 WC Biodiversity Conservation; Ecology; Environmental Sciences SC Biodiversity & Conservation; Environmental Sciences & Ecology GA 706YT UT WOS:000184483200002 ER PT J AU Johnson, NM Fegley, B AF Johnson, NM Fegley, B TI Tremolite decomposition on Venus II. Products, kinetics, and mechanism SO ICARUS LA English DT Article DE venus; mineralogy; tremolite; kinetics; mechanism ID THERMAL-DECOMPOSITION; SELF-DIFFUSION; CRYSTAL-CHEMISTRY; AMPHIBOLES; CROCIDOLITE; WATER; DEHYDROXYLATION; EQUILIBRIA; PARAMETERS; PRESSURE AB We present revised tremolite powder thermal decomposition kinetics using previous and newly acquired data from longer time (years instead of months) and lower temperature experiments (< 1073 K). We also present kinetic results for decomposition of millimeter- to centimeter-sized tremolite grains. Natural tremolite samples were heated at ambient pressure in flowing CO2 or N-2 gas from 1023-1238 K. The tremolite decomposition products are a physical mixture of two pyroxene solid solutions (with the bulk composition Dp(59)En(41)), a silica polymorph, and water vapor. Decomposition rates were calculated by using the mass loss of the heated samples. Tremolite crystals and crystalline powder decompositions follow different but related Avrami-Erofe'ev (nucleation and growth) kinetic models. The rate equations for thermal decomposition of tremolite crystalline powder and the larger crystal grains are log(10)k(powder) (h(-1)) = 18.69(+/-0.19) - 23.845(+/-833)/T and log(10)k(crystal) (h(-1)) = 19.82(+/-0.07) - 25,670(+/-916)/T. The associated apparent activation energies are 456(+/-16) kJ mol(-1) and 491(+/-18) kJ mol(-1), respectively. We propose a decomposition mechanism and suggest that decomposition and dehydroxylation occur simultaneously. The rate-limiting step is proposed to be structural rearrangement of the amphibole structure to the two pyroxenes and silica. This step and the overall decomposition rate are predicted to be independent of pressure from I to 100 bars. These kinetic analyses strengthen our previous conclusion (Johnson and Fegley, 2000, Icarus 146, 301-306) that if hydrous minerals, such as tremolite. formed on Venus during a wetter past, then these minerals could still exist at current conditions on Venus' surface today. (C) 2003 Elsevier Inc. All rights reserved. C1 Washington Univ, Dept Earth & Planetary Sci, Planetary Chem Lab, St Louis, MO 63130 USA. NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. RP Johnson, NM (reprint author), Washington Univ, Dept Earth & Planetary Sci, Planetary Chem Lab, Campus Box 1169, St Louis, MO 63130 USA. RI Johnson, Natasha/E-3093-2012 NR 50 TC 13 Z9 14 U1 1 U2 4 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 AUG PY 2003 VL 164 IS 2 BP 317 EP 333 DI 10.1016/S0019-1035(03)00102-7 PG 17 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 709NH UT WOS:000184630900003 ER PT J AU Brown, RH Baines, KH Bellucci, G Bibring, JP Buratti, BJ Capaccioni, F Cerroni, P Clark, RN Coradini, A Cruikshank, DP Drossart, P Formisano, V Jaumann, R Langevin, Y Matson, DL McCord, TB Mennella, V Nelson, RM Nicholson, PD Sicardy, B Sotin, C Amici, S Chamberlain, MA Filacchione, G Hansen, G Hibbitts, K Showalter, M AF Brown, RH Baines, KH Bellucci, G Bibring, JP Buratti, BJ Capaccioni, F Cerroni, P Clark, RN Coradini, A Cruikshank, DP Drossart, P Formisano, V Jaumann, R Langevin, Y Matson, DL McCord, TB Mennella, V Nelson, RM Nicholson, PD Sicardy, B Sotin, C Amici, S Chamberlain, MA Filacchione, G Hansen, G Hibbitts, K Showalter, M TI Observations with the Visual and Infrared Mapping Spectrometer (VIMS) during Cassini's flyby of Jupiter SO ICARUS LA English DT Article DE Jupiter; Jovian satellites; Jupiter's ring; spectroscopy; planetary atmospheres; planetary surfaces; Cassini mission ID BIDIRECTIONAL REFLECTANCE SPECTROSCOPY; JOVIAN RING; CLOUD STRUCTURE; ATMOSPHERIC COMPOSITION; COHERENT BACKSCATTER; SATELLITES; SYSTEM; SURFACE; SPECTRUM; METHANE AB The Cassini Visual and Infrared Mapping Spectrometer (VIMS) is an imaging spectrometer covering the wavelength range 0.3-5.2 mum in 352 spectral channels, with a nominal instantaneous field of view of 0.5 mrad. The Cassini flyby of Jupiter represented a unique opportunity to accomplish two important goals: scientific observations of the jovian system and functional tests of the VIMS instrument under conditions similar to those expected to obtain during Cassini's 4-year tour of the saturnian system. Results acquired over a complete range of visual to near-infrared wavelengths from 0.3 to 5.2 mum are presented. First detections include methane fluorescence on Jupiter, a surprisingly high opposition surge on Europa, the first visual-near-IR spectra of Himalia and Jupiter's optically-thin ring system, and the first near-infrared observations of the rings over an extensive range of phase angles (0-120degrees). Similarities in the center-to-limb profiles of H-3(+) and CH4 emissions indicate that the H-3(+) ionospheric density is solar-controlled outside of the auroral regions. The existence of jovian NH3 absorption at 0.93 mum is confirmed. Himalia has a slightly reddish spectrum, an apparent absorption near 3 mum, and a geometric albedo of 0.06+/-0.01 at 2.2 mum (assuming an 85-km radius). If the 3-mum feature in Himalia's spectrum is eventually confirmed, it would be suggestive of the presence of water in some form, either free, bound, or incorporated in layer-lattice silicates. Finally, a mean ring-particle radius of 10 mum is found to be consistent with Mie-scattering models fit to VIMS near-infrared observations acquired over 0-120degrees phase angle. (C) 2003 Elsevier Inc. All rights reserved. C1 Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. CNR, Inst Fis Spazio Interplanetario, Rome, Italy. Univ Paris, Inst Astrophys Spatiale, Orsay, France. US Geol Survey, Denver, CO 80255 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Observ Paris, Meudon, France. DLR, Inst Planetary Explorat, Berlin, Germany. Univ Hawaii, HIGP, SOEST, Honolulu, HI USA. INAF, Osservatorio Astron Capodimonte, Rome, Italy. Cornell Univ, Dept Astron, Ithaca, NY 14853 USA. Univ Nantes, Lab Planetol & Geodynam, Nantes, France. Univ Washington, Dept Earth & Space Sci, Seattle, WA 98195 USA. RP Brown, RH (reprint author), Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. RI Chamberlain, Matthew/D-4805-2012; Hibbitts, Charles/B-7787-2016; OI Hibbitts, Charles/0000-0001-9089-4391; Bellucci, Giancarlo/0000-0003-0867-8679; Capaccioni, Fabrizio/0000-0003-1631-4314; Filacchione, Gianrico/0000-0001-9567-0055 NR 47 TC 40 Z9 40 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 AUG PY 2003 VL 164 IS 2 BP 461 EP 470 DI 10.1016/S0019-1035(03)00134-9 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 709NH UT WOS:000184630900010 ER PT J AU Artemieva, N Lunine, J AF Artemieva, N Lunine, J TI Cratering on Titan: impact melt, ejecta, and the fate of surface organics SO ICARUS LA English DT Article ID HYDRODYNAMIC CODE SOVA; ATMOSPHERE; GANYMEDE; CALLISTO; FLOWS; SHELL AB We conduct three-dimensional hydrodynamical simulations of hypervelocity impacts into the crust of Titan to determine the fraction of liquid water generated. under the reasonable assumption that the crust is largely water ice, and to track the fate of the organic-rich layer that is thought to overlie the ice over much of the surface. Impactors larger than a kilometer in diameter are only slightly affected by the atmosphere, while those well under that size are strongly decelerated and broken up before reaching the surface. Impact of a 2 km diameter icy projectile into the crust at velocities of 7 km per second or higher, and angles of impact between 30degrees and 45degrees, generate about 2-5% melt by volume within the crater. Our results for the amount of aqueous melt generated in impacts on Titan are broadly consistent with the analytic model developed by Thompson and Sagan (1992) although our numerical model allows us to more precisely quantify the fraction of melt, and fate of the organics, as a function of the impact parameters. While much of the organic surface layer is heavily shocked and ejected from the immediate region of the crater, a significant fraction located behind the oblique impact trajectory is only lightly shocked and is deposited in the liquid water at the crater base. Simple calculations suggest that the resulting aqueous organic phase may remain liquid for hundreds of years or longer. enough time for the synthesis of simple precursor molecules to the origin of life. (C) 2003 Elsevier Inc. All rights reserved. C1 Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. Russian Acad Sci, Inst Dynam Geospheres, Moscow, Russia. NASA, Jet Prop Lab, Pasadena, CA USA. RP Lunine, J (reprint author), Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. NR 39 TC 49 Z9 50 U1 0 U2 4 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 AUG PY 2003 VL 164 IS 2 BP 471 EP 480 DI 10.1016/s0019-1035(03)00148-9 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 709NH UT WOS:000184630900011 ER PT J AU Lowry, SC Weissman, PR AF Lowry, SC Weissman, PR TI CCD observations of distant comets from Palomar and Steward Observatories SO ICARUS LA English DT Article DE comets; photometry; nuclei ID JUPITER-FAMILY COMETS; SPACE-TELESCOPE OBSERVATIONS; NEAR-EARTH ASTEROIDS; STANDARD STARS; KUIPER-BELT; INNER COMA; NUCLEUS; PHOTOMETRY; SPECTROGRAPH; MAGNITUDES AB We are conducting a ground-based observational study of distant cometary nuclei with the aim of increasing the current database of physical parameters of individual objects, and to estimate the overall distributions of size, rotation period, axial ratio, and color indices. Additionally, we are obtaining CCD spectroscopy and photometry of established and potential targets of current and future spacecraft missions. The results presented here are derived from CCD imaging obtained using the 2.3-m Bok telescope of Steward Observatory (Arizona), obtained in May 2001, and the 5-m Hale telescope at Palomar Observatory (California), obtained in May 2000 and March 2001. Comets observed include 4P/Faye, 6P/d'Arrest, 22P/Kopff, 36P/Whipple, 50P/Arend, 78P/Gehrels 2, 92P/Sanguin, 107P/Wilson-Harrington, and 128P/Shoemaker-Holt 1-A. Of the nine comets observed, only Comets 4P/Faye and 50P/Arend displayed visible coma activity. We have performed either single R filter or multi-filter (BVRI) measurements on these comets, from which we obtain radius and broadband color estimates as well as Afrho values for the active comets. For selected objects we have performed time-series R filter imaging from which we have derived the rotation period and lower limits on the nuclear axial ratio and density. The radius results obtained are included in the cometary nucleus size distribution estimate by Weissman and Lowry (2003). (C) 2003 Elsevier Inc. All rights reserved. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Lowry, SC (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 183-601, Pasadena, CA 91109 USA. NR 60 TC 38 Z9 38 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 AUG PY 2003 VL 164 IS 2 BP 492 EP 503 DI 10.1016/S0019-1035(03)00129-5 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 709NH UT WOS:000184630900013 ER PT J AU Slaveski, F Sluss, J Atiquzzaman, M Nguyen, H Ngo, D AF Slaveski, F Sluss, J Atiquzzaman, M Nguyen, H Ngo, D TI Optical fiber wavelength division multiplexing SO IEEE AEROSPACE AND ELECTRONIC SYSTEMS MAGAZINE LA English DT Article ID LINKS AB During flight, aircraft avionics transmit and receive RF signals to/from antennas over coaxial cables. As the density and complexity of onboard avionics increases, the electromagnetic interference (EMI) environment degrades proportionately, leading to decreasing signal-to-noise ratios (SNRs) and potential safety concerns. The coaxial cables are inherently lossy, limiting the RF signal bandwidth while adding considerable weight. To overcome these limitations, we have investigated a fiber optic communications link for aircraft that utilizes wavelength division multiplexing (WDM) to support the simultaneous transmission of multiple signals (including RF) over a single optical fiber. Optical fiber has many advantages over coaxial cable, particularly lower loss, greater bandwidth, and immunity to EMI. In this paper, we demonstrate that WDM can be successfully used to transmit multiple RF signals over a single optical fiber with no appreciable signal degradation. We investigate the transmission of FM and AM analog modulated signals, as well as FSK digital modulated signals, over a fiber optic link (FOL) employing WDM. We present measurements of power loss, delay, SNR, carrier-to-noise ratio (CNR), total harmonic distortion (THD), and bit error rate (BER). Our experimental results indicate that WDM is a fiber optic technology suitable for avionics applications. C1 Univ Oklahoma, Sch Elect & Comp Engn, Norman, OK 73019 USA. NASA, Glenn Res Ctr, Washington, DC 20546 USA. RP Slaveski, F (reprint author), Univ Oklahoma, Sch Elect & Comp Engn, Norman, OK 73019 USA. NR 9 TC 0 Z9 0 U1 0 U2 2 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 AUG PY 2003 VL 18 IS 8 BP 3 EP 8 DI 10.1109/MAES.2003.1224965 PG 6 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA 714AW UT WOS:000184891000003 ER PT J AU Richter, H Misawa, EA AF Richter, H Misawa, EA TI Stability of discrete-time systems with quantized input and state measurements SO IEEE TRANSACTIONS ON AUTOMATIC CONTROL LA English DT Article DE absolute stability; discrete-time systems; quantized control ID LINEAR-SYSTEMS; CONTROLLER; FEEDBACK; IMPLEMENTATION AB This note focuses on linear discrete-time systems controlled using a quantized input computed from quantized measurements. Nominally stabilizing, but otherwise arbitrary, state feedback gains could result in limit cycling or nonzero equilibrium points. Although a single quantizer is a sector nonlinearity, the presence of a quantizer at each state measurement channel makes traditional absolute stability theory not applicable in a direct way. A global asymptotic, stability condition is obtained by means of a result which allows to apply discrete positive real theory to systems with a sector nonlinearity which is multiplicatively perturbed by a bounded function of the state. The stability result is readily applicable by evaluating the location of the polar plot of a system transfer function relative to a vertical line whose abcissa depends on the one-norm of the feedback gain. A graphical method is also described that can be used to determine the equilibrium points of the closed-loop system for any given feedback gain. C1 NASA, Stennis Space Ctr, Stennis Space Ctr, MS 39529 USA. Oklahoma State Univ, Stillwater, OK 74078 USA. RP NASA, Stennis Space Ctr, Stennis Space Ctr, MS 39529 USA. EM Hanz.Richter-1@nasa.gov; misawa@okstate.edu NR 25 TC 8 Z9 8 U1 1 U2 5 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 0018-9286 EI 1558-2523 J9 IEEE T AUTOMAT CONTR JI IEEE Trans. Autom. Control PD AUG PY 2003 VL 48 IS 8 BP 1453 EP 1458 DI 10.1109/TAC.2003.815044 PG 6 WC Automation & Control Systems; Engineering, Electrical & Electronic SC Automation & Control Systems; Engineering GA 712GC UT WOS:000184788700023 ER PT J AU Sason, I Shamai, S Divsalar, D AF Sason, I Shamai, S Divsalar, D TI Tight exponential upper bounds on the ML decoding error probability of block codes over fully interleaved fading channels SO IEEE TRANSACTIONS ON COMMUNICATIONS LA English DT Article; Proceedings Paper CT 6th International Symposium on Communications Theory and Applications CY JUL, 2001 CL AMBLESIDE, ENGLAND DE block codes; bounds; distance spectrum; fading channels; maximum-likelihood (ML) decoding; uniform interleaver AB We derive in this paper tight exponential upper bounds on the decoding error probability of block codes which are operating over fully interleaved Rician fading channels, coherently detected and maximum-likelihood decoded. It is assumed that the fading samples are statistically independent and that perfect estimates of these samples are provided to the decoder. These upper bounds on the bit and block error probabilities are based on certain variations of the Gallager bounds. These bounds do not require integration in their final version and they are reasonably tight in a certain portion of the rate region exceeding the cutoff rate of the channel. By inserting interconnections between these bounds, we show that they are generalized versions of some reported bounds for the binary-input additive white Gaussian noise channel. C1 Technion Israel Inst Technol, Dept Elect Engn, IL-32000 Haifa, Israel. Sequoia COmmun, Los Angeles, CA USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Sason, I (reprint author), Ecole Polytech Fed Lausanne, Swiss Fed Inst Technol, Dept Comp Sci & Commun, CH-1015 Lausanne, Switzerland. NR 16 TC 14 Z9 14 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 0090-6778 J9 IEEE T COMMUN JI IEEE Trans. Commun. PD AUG PY 2003 VL 51 IS 8 BP 1296 EP 1305 DI 10.1109/TCOMM.2003.815057 PG 10 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA 712GK UT WOS:000184789600012 ER PT J AU Berenji, HR Vengerov, D AF Berenji, HR Vengerov, D TI A convergent actor-critic-based FRL algorithm with application to power management of wireless transmitters SO IEEE TRANSACTIONS ON FUZZY SYSTEMS LA English DT Article DE actor-critic (AC); convergence; fuzzy reinforcement learning (FRL); power control ID FUNCTION APPROXIMATION; NETWORKS; IDENTIFICATION; MODEL AB This paper provides the first convergence proof for fuzzy reinforcement learning (FRL) as well as experimental results supporting our analysis. We extend the work of Konda and Tsitsiklis, who presented a convergent actor-critic (AC) algorithm for a general parameterized actor. In our work we prove that a fuzzy rule-base actor satisfies the necessary conditions that guarantee the convergence of its parameters to a local optimum. Our fuzzy rulebase uses Takagi-Sugeno-Kang rules, Gaussian membership functions, and product inference. As an application domain, we chose a difficult task of power control in wireless transmitters, characterized by delayed rewards and a high degree of stochasticity. To the best of our knowledge, no reinforcement learning algorithms have been previously applied to this task. Our simulation results show that the ACFRL algorithm consistently converges in this domain to a locally optimal policy. C1 NASA, Intelligent Inference Syst Corp, Computat Sci Div, Mountain View, CA 94035 USA. RP Berenji, HR (reprint author), NASA, Intelligent Inference Syst Corp, Computat Sci Div, Res Pk MS-566-106C, Mountain View, CA 94035 USA. NR 27 TC 29 Z9 29 U1 0 U2 4 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 1063-6706 J9 IEEE T FUZZY SYST JI IEEE Trans. Fuzzy Syst. PD AUG PY 2003 VL 11 IS 4 BP 478 EP 485 DI 10.1109/TFUZZ.2003.814834 PG 8 WC Computer Science, Artificial Intelligence; Engineering, Electrical & Electronic SC Computer Science; Engineering GA 712GP UT WOS:000184790200005 ER PT J AU Kaufman, YJ Tanre, D Leon, JF Pelon, J AF Kaufman, YJ Tanre, D Leon, JF Pelon, J TI Retrievals of profiles of fine and coarse aerosols using lidar and radiometric space measurements SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE aerosol; lidar; remote sensing ID OPTICAL-PROPERTIES; SIZE DISTRIBUTION; SAHARAN DUST; AIR-POLLUTION; TROPOSPHERIC AEROSOLS; TROPICAL ATLANTIC; LIGHT-SCATTERING; BOUNDARY-LAYER; OCEAN; ATMOSPHERE AB The Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) spaceborne lidar, expected to be launched in 2004, will collect profiles of the lidar attenuated backscattering coefficients of aerosol and clouds at 0.53 and 1.06 mum. The measurements are sensitive to the vertical distribution of aerosols. However, the information is insufficient to be mapped into unique aerosol physical properties and vertical distribution. Spectral radiances measured by the Moderate Resolution Imaging Spectrometer (MODIS) on the Aqua spacecraft, acquired simultaneously with the CALIPSO observations, can constrain the solutions. The combination of the MODIS and CALIPSO data can be used to derive extinction profiles of the fine and coarse modes of the aerosol size distribution for aerosol optical thickness of 0.1 and larger. Here we describe a new inversion method developed to invert simultaneously MODIS and CALIPSO data over glint-free ocean. The method is applied to aircraft lidar and MODIS data collected over a dust storm off the coast of West Africa during the Saharan Dust Experiment (SHADE). The backscattering-to-extinction ratio (BER) (BER = omega(o)P(180)/4pi) can be retrieved from the synergism between measurements avoiding a priori hypotheses required for inverting lidar measurements alone. For dust, the resultant value of BER = 0.016 sr(-1) is over 50% smaller than what is expected using Mie theory, but in good agreement with recent results obtained from Raman lidar observations of dust episodes. The inversion is robust in the presence of 10% and 20% noise in the lidar signal at 0.53 and 1.06 pm, respectively. Calibration errors of the lidar of 5% to 10% can cause an error in optical thickness of 20% to 40%, respectively, in the tested cases. C1 Goddard Space Flight Ctr, Climate & Radiat Branch, Greenbelt, MD 20771 USA. Univ Sci & Tech Lille, CNRS, Opt Atmospher Lab, F-59665 Villeneuve Dascq, France. Univ Paris 06, Serv Aeron, Inst Pierre Simon Laplace, F-75252 Paris, France. RP Kaufman, YJ (reprint author), Goddard Space Flight Ctr, Climate & Radiat Branch, Greenbelt, MD 20771 USA. NR 49 TC 34 Z9 35 U1 1 U2 5 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 AUG PY 2003 VL 41 IS 8 BP 1743 EP 1754 DI 10.1109/TGRS.2003.814138 PG 12 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 713MJ UT WOS:000184861700001 ER PT J AU Chen, CT Tsang, L Guo, JJ Chang, ATC Ding, KH AF Chen, CT Tsang, L Guo, JJ Chang, ATC Ding, KH TI Frequency dependence of scattering and extinction of dense media based on three-dimensional simulations of Maxwell's equations with applications to snow SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE electromagnetic wave scattering; Monte Carlo method; passive microwave remote sensing ID MONTE-CARLO SIMULATIONS; SPHERES; PARTICLES; APPROXIMATION; PROPAGATION; MODEL AB The frequency dependence of scattering by geophysical media at microwave frequencies is an important topic because multifrequency measurements are used in remote sensing applications. In this paper, we study rigorously the frequency dependence of scattering by dense media using Monte Carlo simulations of the three-dimensional solutions of Maxwell's equations. The particle positions are generated by deposition and bonding techniques. The extinction, scattering, and absorption properties of dense media are calculated for dense media of sticky and nonsticky particles. Numerical solutions of Maxwell's equations indicate that the frequency dependence of densely packed sticky small particles are much weaker than that of independent scattering. Numerical results are illustrated using parameters of snow in microwave remote sensing. Comparisons are made with extinction measurements as a function of frequency. C1 Univ Washington, Dept Elect Engn, Seattle, WA 98195 USA. City Univ Hong Kong, Dept Elect Engn, Hong Kong, Hong Kong, Peoples R China. NASA, Goddard Space Flight Ctr, Hydrol Sci Branch, Greenbelt, MD 20771 USA. USAF, Res Lab, Sensors Directorate, SNHE, Hanscom AFB, MA 01731 USA. RP Chen, CT (reprint author), Univ Washington, Dept Elect Engn, Seattle, WA 98195 USA. NR 28 TC 19 Z9 20 U1 0 U2 2 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 AUG PY 2003 VL 41 IS 8 BP 1844 EP 1852 DI 10.1109/TGRS.2003.811812 PG 9 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 713MJ UT WOS:000184861700010 ER PT J AU Economou, DJ Meyyappan, M Makabe, T AF Economou, DJ Meyyappan, M Makabe, T TI Guest editorial - Special issue on modeling and simulation of collisional or near-collisionless low-temperature plasmas SO IEEE TRANSACTIONS ON PLASMA SCIENCE LA English DT Editorial Material C1 Univ Houston, Dept Chem Engn, Houston, TX 77204 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Keio Univ, Dept Elect & Elect Engn, Yokohama, Kanagawa 2238522, Japan. RP Economou, DJ (reprint author), Univ Houston, Dept Chem Engn, Houston, TX 77204 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 0093-3813 J9 IEEE T PLASMA SCI JI IEEE Trans. Plasma Sci. PD AUG PY 2003 VL 31 IS 4 BP 462 EP 463 DI 10.1109/TPS.2003.816898 PN 1 PG 2 WC Physics, Fluids & Plasmas SC Physics GA 713AW UT WOS:000184833400001 ER PT J AU Bose, D Govindan, TR Meyyappan, M AF Bose, D Govindan, TR Meyyappan, M TI Modeling of a helicon plasma source SO IEEE TRANSACTIONS ON PLASMA SCIENCE LA English DT Article DE helicon plasma; modeling; plasma discharges ID COUPLED PLASMA; GENERALIZED THEORY; WAVES; REACTOR; ABSORPTION; ENERGY AB A two-dimensional axisymmetric helicon plasma source with three-dimensional wave components is modeled. Plasma fluid equations are solved self-consistently with helicon wave equations. Electron inertia is taken into account to simulate the propagation of electrostatic wave components. The purpose of this paper is to describe the model in detail and present the results to verify wave propagation characteristics, power deposition mechanisms, especially bulk versus peripheral power absorption. We also study the effect of wave absorption characteristics on discharge plasma density and temperature profiles. C1 ELORET Corp, Ames Res Ctr, Moffett Field, CA 94035 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Bose, D (reprint author), ELORET Corp, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 21 TC 3 Z9 3 U1 1 U2 3 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 0093-3813 J9 IEEE T PLASMA SCI JI IEEE Trans. Plasma Sci. PD AUG PY 2003 VL 31 IS 4 BP 464 EP 470 DI 10.1109/TPS.2003.815475 PN 1 PG 7 WC Physics, Fluids & Plasmas SC Physics GA 713AW UT WOS:000184833400002 ER PT J AU Hornby, GS Lipson, H Pollack, JB AF Hornby, GS Lipson, H Pollack, JB TI Generative representations for the automated design of modular physical robots SO IEEE TRANSACTIONS ON ROBOTICS AND AUTOMATION LA English DT Article; Proceedings Paper CT IEEE International Conference on Robotics and Automation CY MAY 21-26, 2001 CL SEOUL, SOUTH KOREA SP IEEE Robot & Automat Soc, IEEE DE design automation; evolutionary robotics; generative representations ID SYSTEMS AB The field of evolutionary robotics has demonstrated the ability to automatically design the morphology and controller of simple physical robots through synthetic evolutionary processes. However, it is not clear if variation-based search processes can attain the complexity of design necessary for practical engineering of robots. Here., we demonstrate an automatic design system that produces complex robots by exploiting the principles of regularity, modularity, hierarchy, and reuse. These techniques are already established principles of scaling in engineering design and have been observed in nature, but have not been broadly used in artificial evolution. We gain these advantages through the use of a generative representation, which combines a programmatic representation with an algorithmic process that compiles the representation into a detailed construction plan. This approach is shown to have two benefits: it can reuse components in regular and hierarchical ways, providing a systematic way to create more complex modules from simpler ones; and the evolved representations can capture intrinsic properties of the design space, so that variations in the representations move through the design space more effectively than equivalent-sized changes in a nongenerative representation. Using this system, we demonstrate for the first time the evolution and construction of modular, three-dimensional, physically locomoting robots, comprising many more components than previous work on body-brain evolution. C1 Brandeis Univ, Dept Comp Sci, Ctr Complex Syst, Waltham, MA 02454 USA. RP QSS Grp Inc, Ames Res Ctr, Computat Sci Div, NASA, Moffett Field, CA 94035 USA. EM hornby@email.arc.nasa.gov; Hod.Lipson@cornell.edu; pollack@cs.brandeis.edu NR 50 TC 57 Z9 57 U1 0 U2 4 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 1042-296X J9 IEEE T ROBOTIC AUTOM JI IEEE Trans. Robot. Autom. PD AUG PY 2003 VL 19 IS 4 BP 703 EP 719 DI 10.1109/TRA.2003.814502 PG 17 WC Automation & Control Systems; Engineering, Electrical & Electronic; Robotics SC Automation & Control Systems; Engineering; Robotics GA 712GN UT WOS:000184790100014 ER PT J AU Catalano, P Wang, M Iaccarino, G Moin, P AF Catalano, P Wang, M Iaccarino, G Moin, P TI Numerical simulation of the flow around a circular cylinder at high Reynolds numbers SO INTERNATIONAL JOURNAL OF HEAT AND FLUID FLOW LA English DT Article; Proceedings Paper CT 5th International Symposium on Engineering Turbulence Modelling and Measurements CY SEP 16-18, 2002 CL MALLORCA, SPAIN SP Spanish Minist Sci & Technol, Univ Zaragoza, Univ Karlsruhe, USAF, European Off Aerosp Res & Dev, CFX Germany, DaimlerChrysler AG, Elect France, NEC European Supercomp Syst DE large-eddy simulation; wall modeling; unsteady RANS; high reynolds number flows; circular cylinder; Navier-Stokes equations ID LARGE-EDDY SIMULATION; BOUNDARY-CONDITIONS; TURBULENT FLOWS AB The viability and accuracy of large-eddy simulation (LES) with wall modeling for high Reynolds number complex turbulent flows is investigated by considering the flow around a circular cylinder in the supercritical regime. A simple wall stress model is employed to provide approximate boundary conditions to the LES. The results are compared with those obtained from steady and unsteady Reynolds-averaged Navier-Stokes (RANS) solutions and the available experimental data. The LES solutions are shown to be considerably more accurate than the RANS results. They capture correctly the delayed boundary layer separation and reduced drag coefficients consistent with experimental measurements after the drag crisis. The mean pressure distribution is predicted reasonably well at Re-D = 5 x 10(5) and 10(6). However, the Reynolds number dependence is not captured, and the solution becomes less accurate at increased Reynolds numbers. (C) 2003 Elsevier Science Inc. All rights reserved. C1 Italian Aerosp Res Ctr, I-81043 Capua, CE, Italy. Stanford Univ, NASA, Ames Res Ctr, Ctr Turbulence Res, Stanford, CA 94305 USA. RP Catalano, P (reprint author), Italian Aerosp Res Ctr, I-81043 Capua, CE, Italy. RI Iaccarino, Gianluca/H-5284-2011; Wang, Meng/C-1622-2012 NR 17 TC 95 Z9 105 U1 1 U2 46 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0142-727X J9 INT J HEAT FLUID FL JI Int. J. Heat Fluid Flow PD AUG PY 2003 VL 24 IS 4 BP 463 EP 469 DI 10.1016/S0142-727X(03)00061-4 PG 7 WC Thermodynamics; Engineering, Mechanical; Mechanics SC Thermodynamics; Engineering; Mechanics GA 689UR UT WOS:000183511800006 ER PT J AU Librescu, L Qin, ZM Ambur, DR AF Librescu, L Qin, ZM Ambur, DR TI Implications of warping restraint on statics and dynamics of elastically tailored thin-walled composite beams SO INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES LA English DT Article DE thin-walled beams; elastic tailoring; anisotropic; composite materials; warping restraint; Saint-Venant twist ID AEROELASTIC DIVERGENCE; WING STRUCTURES; AIRCRAFT WINGS; VIBRATION AB Static response and free vibration of elastically tailored thin-walled beams accounting for the warping restraint effect are investigated via an exact solution methodology within the context of a refined beam model. Analytical results obtained from the restrained warping model are compared with those based on its Saint-Venant model counterpart. It is revealed that the beam slenderness and thickness ratio, as well as the elastic anisotropy, considered in conjunction with the warping restraint have profound effects on the static and dynamic response characteristics. It is also shown that even for anisotropic composite thin-walled beams with high slenderness ratios, warping restraint can still be significant, implying the inadequacy of merely considering the geometric aspects in the modeling of anisotropic composite thin-walled beams. (C) 2003 Elsevier Ltd. All rights reserved. C1 Virginia Polytech Inst & State Univ, Dept Engn Sci & Mech, Blacksburg, VA 24061 USA. NASA, Langley Res Ctr, Mech & Durabil Branch, Hampton, VA 23681 USA. RP Librescu, L (reprint author), Virginia Polytech Inst & State Univ, Dept Engn Sci & Mech, Mail Case 0219, Blacksburg, VA 24061 USA. EM librescu@vt.edu NR 16 TC 10 Z9 12 U1 1 U2 4 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0020-7403 J9 INT J MECH SCI JI Int. J. Mech. Sci. PD AUG PY 2003 VL 45 IS 8 BP 1247 EP 1267 DI 10.1016/j.ijmecsci.2003.10.003 PG 21 WC Engineering, Mechanical; Mechanics SC Engineering; Mechanics GA 760QD UT WOS:000187844500001 ER PT J AU Noor, AK Bechtel, SE Ghosh, S AF Noor, AK Bechtel, SE Ghosh, S TI International Journal of Solids and Structures honoring the 70th birthday of Arthur W. Leissa - Preface SO INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES LA English DT Biographical-Item C1 Old Dominion Univ, NASA, Langley Res Ctr, Ctr Adv Engn Environm, Hampton, VA 23681 USA. RP Noor, AK (reprint author), Old Dominion Univ, NASA, Langley Res Ctr, Ctr Adv Engn Environm, MS 269,Mail Stop 201, Hampton, VA 23681 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 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 AUG PY 2003 VL 40 IS 16 BP 4093 EP 4095 DI 10.1016/S0020-7683(03)00219-1 PG 3 WC Mechanics SC Mechanics GA 697MN UT WOS:000183947100001 ER PT J AU Song, J Peters, J Noor, A Michaleris, P AF Song, J Peters, J Noor, A Michaleris, P TI Sensitivity analysis of the thermomechanical response of welded joints SO INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES LA English DT Article; Proceedings Paper CT Symposium in Honor of Arthur W Leissas 70th Birthday CY JUN, 2002 CL VIRGINIA POLYTECH INST & STATE UNIV, BLACKSBURG, VA HO VIRGINIA POLYTECH INST & STATE UNIV DE welding; finite element analysis; thermal analysis; Lagrangian frame; residual stresses; sensitivity analysis ID STRESS-ANALYSIS; TRANSIENT AB A computational procedure is presented for evaluating the sensitivity coefficients of the thermomechanical response of welded structures. Uncoupled thermomechanical analysis, with transient thermal analysis and quasi-static mechanical analysis, is performed. A rate independent, small deformation thermo-elasto-plastic material model with temperature-dependent material properties is adopted in the study. The temperature field is assumed to be independent of the stresses and strains. The heat transfer equations emanating from a finite element semi-discretization are integrated using an implicit backward difference scheme to generate the time history of the temperatures. The mechanical response during welding is then calculated by solving a generalized plane strain problem. First- and second-order sensitivity coefficients of the thermal and mechanical response quantities (derivatives with respect to various thermomechanical parameters) are evaluated using a direct differentiation approach in conjunction with an automatic differentiation software facility. Numerical results are presented for a double fillet conventional welding of a stiffener and a base plate made of stainless steel AL-6XN material. Time histories of the response and sensitivity coefficients, and their spatial distributions at selected times are presented. (C) 2003 Elsevier Science Ltd. All rights reserved. C1 Old Dominion Univ, Ctr Adv Engn Environm, NASA, Langley Res Ctr, Hampton, VA 23681 USA. Penn State Univ, Dept Mech & Nucl Engn, University Pk, PA 16802 USA. Univ Florida, Gainesville, FL USA. RP Noor, A (reprint author), Old Dominion Univ, Ctr Adv Engn Environm, NASA, Langley Res Ctr, MS 201, Hampton, VA 23681 USA. EM a.k.noor@larc.nasa.gov NR 26 TC 13 Z9 13 U1 0 U2 5 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 AUG PY 2003 VL 40 IS 16 BP 4167 EP 4180 DI 10.1016/S0020-7683(03)00223-3 PG 14 WC Mechanics SC Mechanics GA 697MN UT WOS:000183947100007 ER PT J AU Zhang, GF Vivekanandan, J Brandes, EA Meneghini, R Kozu, T AF Zhang, GF Vivekanandan, J Brandes, EA Meneghini, R Kozu, T TI The shape-slope relation in observed gamma raindrop size distributions: Statistical error or useful information? SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article ID POLARIMETRIC RADAR AB The three-parameter gamma distribution n( D) 5 N0Dmu exp(-LambdaD) is often used to characterize a raindrop size distribution ( DSD). The parameters m and L correspond to the shape and slope of the DSD. If mu and Lambda are related to one another, as recent disdrometer measurements suggest, the gamma DSD model is simplified, which facilitates retrieval of rain parameters from remote measurements. It is important to determine whether the mu-Lambda relation arises from errors in estimated DSD moments, or from natural rain processes, or from a combination of both statistical error and rain physics. In this paper, the error propagation from moment estimators to rain DSD parameter estimators is studied. The standard errors and correlation coefficient are derived through systematic error analysis. Using numerical simulations, errors in estimated DSD parameters are quantified. The analysis shows that errors in moment estimators do cause correlations among the estimated DSD parameters and cause a linear relation between estimators (μ) over cap and (&ULambda;) over tilde. However, the slope and intercept of the error-induced relation depend on the expected values mu and Lambda, and it differs from the m - L relation derived from disdrometer measurements. Further, the mean values of the DSD parameter estimators are unbiased. Consequently, the derived mu-Lambda relation is believed to contain useful information in that it describes the mean behavior of the DSD parameters and reflects a characteristic of actual raindrop size distributions. The mu-Lambda relation improves retrievals of rain parameters from a pair of remote measurements such as reflectivity and differential reflectivity or attenuation, and it reduces the bias and standard error in retrieved rain parameters. C1 Natl Ctr Atmospher Res, RAP, Boulder, CO 80307 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD USA. Shimane Univ, Dept Elect & Control Syst Engn, Matsue, Shimane, Japan. RP Zhang, GF (reprint author), Natl Ctr Atmospher Res, RAP, 3450 Mitchell Lane,Bldg 2, Boulder, CO 80307 USA. RI Zhang, Guifu/M-3178-2014 OI Zhang, Guifu/0000-0002-0261-2815 NR 19 TC 67 Z9 72 U1 1 U2 11 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 AUG PY 2003 VL 20 IS 8 BP 1106 EP 1119 DI 10.1175/1520-0426(2003)020<1106:TSRIOG>2.0.CO;2 PG 14 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA 709GT UT WOS:000184618000003 ER PT J AU Kato, S Loeb, NG AF Kato, S Loeb, NG TI Twilight irradiance reflected by the Earth estimated from clouds and the Earth's Radiant Energy System (CERES) measurements SO JOURNAL OF CLIMATE LA English DT Article ID BUDGET AB The upward shortwave irradiance at the top of the atmosphere when the solar zenith angle is greater than 90degrees ( twilight irradiance) is estimated from radiance measurements by the Clouds and the Earth's Radiant Energy System (CERES) instrument on the Tropical Rainfall Measuring Mission (TRMM) satellite. The irradiance decreases with solar zenith angle from 7.5 W m(-2) at 90.5degrees to 0.6 W m(-2) at 95.5degrees. The global and daily average twilight irradiance is 0.2 W m(-2), which is three orders of magnitude smaller than the daily and global average reflected irradiance at the top of the atmosphere. Therefore, the twilight irradiance can be neglected in global radiation budget estimate. The daily average twilight irradiance, however, can be more than 1 W m(-2) at polar regions during seasons when the sun stays just below the horizon for a long period of time. C1 Hampton Univ, Ctr Atmospher Sci, Hampton, VA 23668 USA. RP Kato, S (reprint author), NASA, Langley Res Ctr, Mail Stop 420, Hampton, VA 23681 USA. NR 11 TC 7 Z9 7 U1 0 U2 0 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 AUG 1 PY 2003 VL 16 IS 15 BP 2646 EP 2650 DI 10.1175/1520-0442(2003)016<2646:TIRBTE>2.0.CO;2 PG 5 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 706JL UT WOS:000184450500015 ER PT J AU Barker, HW Stephens, GL Partain, PT Bergman, JW Bonnel, B Campana, K Clothiaux, EE Clough, S Cusack, S Delamere, J Edwards, J Evans, KF Fouquart, Y Freidenreich, S Galin, V Hou, Y Kato, S Li, J Mlawer, E Morcrette, JJ O'Hirok, W Raisanen, P Ramaswamy, V Ritter, B Rozanov, E Schlesinger, M Shibata, K Sporyshev, P Sun, Z Wendisch, M Wood, N Yang, F AF Barker, HW Stephens, GL Partain, PT Bergman, JW Bonnel, B Campana, K Clothiaux, EE Clough, S Cusack, S Delamere, J Edwards, J Evans, KF Fouquart, Y Freidenreich, S Galin, V Hou, Y Kato, S Li, J Mlawer, E Morcrette, JJ O'Hirok, W Raisanen, P Ramaswamy, V Ritter, B Rozanov, E Schlesinger, M Shibata, K Sporyshev, P Sun, Z Wendisch, M Wood, N Yang, F TI Assessing 1D atmospheric solar radiative transfer models: Interpretation and handling of unresolved clouds SO JOURNAL OF CLIMATE LA English DT Article ID BOUNDARY-LAYER CLOUDS; GENERAL-CIRCULATION MODEL; CLIMATE MODELS; WATER CLOUDS; HORIZONTAL VARIABILITY; 2-STREAM APPROXIMATION; OVERLAP STATISTICS; OPTICAL-PROPERTIES; SULFATE AEROSOLS; CIRRUS CLOUDS AB The primary purpose of this study is to assess the performance of 1D solar radiative transfer codes that are used currently both for research and in weather and climate models. Emphasis is on interpretation and handling of unresolved clouds. Answers are sought to the following questions: (i) How well do 1D solar codes interpret and handle columns of information pertaining to partly cloudy atmospheres? (ii) Regardless of the adequacy of their assumptions about unresolved clouds, do 1D solar codes perform as intended? One clear-sky and two plane-parallel, homogeneous (PPH) overcast cloud cases serve to elucidate 1D model differences due to varying treatments of gaseous transmittances, cloud optical properties, and basic radiative transfer. The remaining four cases involve 3D distributions of cloud water and water vapor as simulated by cloud-resolving models. Results for 25 1D codes, which included two line-by-line (LBL) models (clear and overcast only) and four 3D Monte Carlo (MC) photon transport algorithms, were submitted by 22 groups. Benchmark, domain-averaged irradiance profiles were computed by the MC codes. For the clear and overcast cases, all MC estimates of top-of-atmosphere albedo, atmospheric absorptance, and surface absorptance agree with one of the LBL codes to within +/-2%. Most 1D codes underestimate atmospheric absorptance by typically 15-25 W m(-2) at overhead sun for the standard tropical atmosphere regardless of clouds. Depending on assumptions about unresolved clouds, the 1D codes were partitioned into four genres: (i) horizontal variability, (ii) exact overlap of PPH clouds, (iii) maximum/random overlap of PPH clouds, and (iv) random overlap of PPH clouds. A single MC code was used to establish conditional benchmarks applicable to each genre, and all MC codes were used to establish the full 3D benchmarks. There is a tendency for 1D codes to cluster near their respective conditional benchmarks, though intragenre variances typically exceed those for the clear and overcast cases. The majority of 1D codes fall into the extreme category of maximum/random overlap of PPH clouds and thus generally disagree with full 3D benchmark values. Given the fairly limited scope of these tests and the inability of any one code to perform extremely well for all cases begs the question that a paradigm shift is due for modeling 1D solar fluxes for cloudy atmospheres. C1 Meteorol Serv Canada, Cloud Phys Res Div ARMP, Downsview, ON M3H 5T4, Canada. Colorado State Univ, Ft Collins, CO 80523 USA. NOAA, CIRES Climate Diagnost Ctr, Boulder, CO USA. Opt Atmospher Lab, Lille, France. Natl Ctr Environm Predict, Camp Springs, MD USA. Penn State Univ, University Pk, PA 16802 USA. Atmospher Environm Res, Lexington, MA USA. Meteorol Off, Bracknell RB12 2SZ, Berks, England. Univ Colorado, Boulder, CO 80309 USA. Princeton Univ, GFDL, Princeton, NJ 08544 USA. DNM, Moscow, Russia. Hampton Univ, Hampton, VA 23668 USA. NASA, Langley Res Ctr, Hampton, VA 23665 USA. Meteorol Serv Canada, Victoria, BC, Canada. ECMWF, Reading, Berks, England. Univ Calif Santa Barbara, Santa Barbara, CA 93106 USA. Univ Helsinki, Helsinki, Finland. Deutsch Wetterdienst, Offenbach, Germany. Univ Illinois, Urbana, IL 61801 USA. Meteorol Res Inst, Tsukuba, Ibaraki 305, Japan. Voeikov Main Geophys Observ, St Petersburg, Russia. Bur Meteorol, Melbourne, Vic, Australia. Inst Tropospher Res, Leipzig, Germany. RP Meteorol Serv Canada, Cloud Phys Res Div ARMP, 4905 Dufferin St, Downsview, ON M3H 5T4, Canada. EM howard.barker@ec.gc.ca RI Raisanen, Petri/I-1954-2012; Wendisch, Manfred/E-4175-2013; Rozanov, Eugene/A-9857-2012; Sporyshev, Petr/P-7323-2015; Li, Jiangnan/J-6262-2016; Yang, Fanglin/A-1948-2013 OI Raisanen, Petri/0000-0003-4466-213X; Wendisch, Manfred/0000-0002-4652-5561; Rozanov, Eugene/0000-0003-0479-4488; Sporyshev, Petr/0000-0002-4047-8178; NR 78 TC 75 Z9 80 U1 1 U2 18 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 AUG PY 2003 VL 16 IS 16 BP 2676 EP 2699 DI 10.1175/1520-0442(2003)016<2676:ADASRT>2.0.CO;2 PG 24 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 708HA UT WOS:000184560100003 ER PT J AU Sommer, AP Oron, U Pretorius, AM McKay, DS Ciftcioglu, N Mester, AR Kajander, EO Whelan, HT AF Sommer, AP Oron, U Pretorius, AM McKay, DS Ciftcioglu, N Mester, AR Kajander, EO Whelan, HT TI A preliminary investigation into light-modulated replication of nanobacteria and heart disease SO JOURNAL OF CLINICAL LASER MEDICINE & SURGERY LA English DT Article ID KIDNEY-STONE FORMATION; LASER IRRADIATION; IN-VITRO; CELLS; DRUGS AB Objective: The purpose of this preliminary study is to evaluate the effect of various wavelengths of light on nanobacteria (NB). Background Data: NB and mitochondria use light for biological processes. NB have been described as multifunctional primordial nanovesicles with the potential to utilize solar energy for replication. NB produce slime, a process common to living bacteria. Slime release is an evolutionary important stress-dependent phenomenon increasing the survival chance of individual bacteria in a colony. In the cardiovascular system, stress-induced bacterial colony formation may lead to a deposition of plaque. Methods: Cultured NB were irradiated with NASA-LEDs at different wavelengths of light: 670, 728 and 880 run. Light intensities were about 500k Wm(-2), and energy density was 1 X 10(4) J m(-2). Results: Monochromatic light clearly affected replication of NB. Maximum replication was achieved at 670 nm. Conclusions: The results indicate that suitable wavelengths of light could be instrumental in elevating the vitality level of NB, preventing the production of NB-mediated slime, and simultaneously increasing the vitality level of mitochondria. The finding could stimulate the design of cooperative therapy concepts that could reduce death caused by myocardial infarcts. C1 Univ Ulm, Cent Inst Biomed Engn, D-89081 Ulm, Germany. Tel Aviv Univ, Fac Life Sci, Dept Zool, IL-69978 Tel Aviv, Israel. Univ Orange Free State, Dept Med Microbiol, Natl Hlth Lab Serv, ZA-9300 Bloemfontein, South Africa. NASA, Lyndon B Johnson Space Ctr, Univ Space Res Assoc, Houston, TX 77058 USA. Semmelweis Univ, Dept Radiol & Oncotherapy, H-1082 Budapest, Hungary. Univ Kuopio, Dept Biochem, Kuopio, Finland. Med Coll Wisconsin, Dept Neurol, Milwaukee, WI 53226 USA. RP Sommer, AP (reprint author), Univ Ulm, Cent Inst Biomed Engn, D-89081 Ulm, Germany. EM samoan@gmx.net NR 30 TC 13 Z9 16 U1 1 U2 2 PU MARY ANN LIEBERT INC PI NEW ROCHELLE PA 140 HUGUENOT STREET, 3RD FL, NEW ROCHELLE, NY 10801 USA SN 1044-5471 J9 J CLIN LASER MED SUR JI J. Clin. Laser Med. Sur. PD AUG PY 2003 VL 21 IS 4 BP 231 EP 235 DI 10.1089/104454703768247819 PG 5 WC Engineering, Biomedical; Surgery SC Engineering; Surgery GA 716NJ UT WOS:000185034900009 PM 13678461 ER PT J AU Ortiz, RM Wade, CE Ortiz, CL Talamantes, F AF Ortiz, RM Wade, CE Ortiz, CL Talamantes, F TI Acutely elevated vasopressin increases circulating concentrations of cortisol and aldosterone in fasting northern elephant seal (Mirounga angustirostris) pups SO JOURNAL OF EXPERIMENTAL BIOLOGY LA English DT Article DE aldosterone; cortisol; corticotropin-releasing factor; glomerular filtration rate; natriuresis; osmotic clearance; northern elephant seal; Mirounga angustirostris ID PLASMA ANGIOTENSIN-II; CONSCIOUS DOGS; ELECTROLYTE EXCRETION; SODIUM-EXCRETION; BLOOD-PRESSURE; RENIN ACTIVITY; WATER; AVP; SHEEP; RATS AB The physiological actions of vasopressin (VP) in marine mammals are not well defined. To help elucidate its hormonal and renal effects in this group of mammals, northern elephant seal (Mirounga angustirostris) pups (N=7; 99+/-4 kg) were first infused with 0.9% saline (control; 220 nil), followed 24 h later with VP (as a 20 ng kg(-1) bolus, then 2 ng kg(-1) min(-1) for approximately 35 min in 225+/-16 ml saline). During both control and VP periods, blood samples were collected prior to infusion, and 15, 30, 60, 120 min and 24 h after infusion to examine the hormonal responses of the pups to VP. Renal responses were quantified from 24 h urine samples obtained prior to infusion (control) and 24 h post-infusion. Compared to the control period, infusion of VP increased plasma concentrations of cortisol over a 120 min period and aldosterone over 30 min, while plasma renin activity (PRA) was decreased for a 120 min period. The plasma urea:creatinine ratio was elevated following infusion of VP. Urine output and osmotic clearance were increased by 69+/-18% (mean S.EAM.) and 36+/-10%, respectively, but free water clearance and glomerular filtration rate were not significantly altered 24 h post-infusion of VP. Solute (osmolality, Na+, K+ and Cl-) excretion and fractional excretion of electrolytes were also increased when compared to control values. The increase in cortisol concentration suggests that VP may possess corticotropin releasing hormone-like activity in elephant seals. If osmotic diuresis and natriuresis are typical consequences of elevated [VP] in fasting pups, then not increasing VP normally during the fast may serve as a protective mechanism to avoid the potential loss of Na+ induced by elevated [VP]. Therefore, under natural fasting conditions, pups may be highly sensitive to small changes in [VP], resulting in the maintenance of water and electrolyte balance. C1 Univ Calif Santa Cruz, Dept Biol, Santa Cruz, CA 95064 USA. NASA, Ames Res Ctr, Div Life Sci, Neuroendocrinol Lab, Moffett Field, CA 94035 USA. RP Ortiz, RM (reprint author), Tulane Univ, Hlth Sci Ctr, Dept Physiol SL39, New Orleans, LA 70112 USA. FU NIGMS NIH HHS [GM 58903-01] NR 41 TC 7 Z9 8 U1 0 U2 5 PU COMPANY OF BIOLOGISTS LTD PI CAMBRIDGE PA BIDDER BUILDING CAMBRIDGE COMMERCIAL PARK COWLEY RD, CAMBRIDGE CB4 4DL, CAMBS, ENGLAND SN 0022-0949 J9 J EXP BIOL JI J. Exp. Biol. PD AUG PY 2003 VL 206 IS 16 BP 2795 EP 2802 DI 10.1242/jebs.00485 PG 8 WC Biology SC Life Sciences & Biomedicine - Other Topics GA 755FM UT WOS:000187392900014 PM 12847125 ER PT J AU Rinsland, CP Weisenstein, DK Ko, MKW Scott, CJ Chiou, LS Mahieu, E Zander, R Demoulin, P AF Rinsland, CP Weisenstein, DK Ko, MKW Scott, CJ Chiou, LS Mahieu, E Zander, R Demoulin, P TI Post-Mount Pinatubo eruption ground-based infrared stratospheric column measurements of HNO3, NO, and NO2 and their comparison with model calculations SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID 1996 HITRAN UPDATE; NITRIC-ACID; SPECTROSCOPIC MEASUREMENTS; HETEROGENEOUS CONVERSION; ATMOSPHERIC NO2; 2-DIMENSIONAL MODEL; REACTIVE NITROGEN; DAYTIME VARIATION; SULFATE AEROSOLS; ATMOS EXPERIMENT AB [1] Infrared solar spectra recorded between July 1991 to March 1992 and November 2002 with the Fourier transform spectrometer on Kitt Peak (31.9degreesN latitude, 111.6degreesW longitude, 2.09 km altitude) have been analyzed to retrieve stratospheric columns of HNO3, NO, and NO2. The measurements cover a decade time span following the June 1991 Mount Pinatubo volcanic eruption and were recorded typically at 0.01 cm(-1) spectral resolution. The measured HNO3 stratospheric column shows a 20% decline from 9.16 x 10(15) molecules cm(-2) from the first observation in March 1992 to 7.40 x 10(15) molecules cm(-2) at the start of 1996 reaching a broad minimum of 6.95 x 10(15) molecules cm(-2) thereafter. Normalized daytime NO and NO2 stratospheric column trends for the full post-Pinatubo eruption time period equal (+ 1.56 +/- 0.45)% yr(-1), 1 sigma, and (+ 0.52 +/- 0.32)% yr(-1), 1 sigma, respectively. The long-term trends are superimposed on seasonal cycles with similar to 10% relative amplitudes with respect to mean values, winter maxima for HNO3 and summer maxima for NO and NO2. The measurements have been compared with two-dimensional model calculations utilizing version 6.1 Stratospheric Aerosol and Gas Experiment ( SAGE) II sulfate aerosol surface area density measurements through 1999 and extended to the end of the time series by repeating the 1999 values. The model-calculated HNO3, NO, and NO2 stratospheric column time series agree with the measurements to within similar to8% after taking into account the vertical sensitivity of the ground-based measurements. The consistency between the measured and model-calculated stratospheric time series confirms the decreased impact on stratospheric reactive nitrogen chemistry of the key heterogeneous reaction that converts reactive nitrogen to its less active reservoir form as the lower-stratospheric aerosol surface area density declined by a factor of similar to20 after the eruption maximum. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. Atmospher & Environm Res Inc, Lexington, MA 02421 USA. Sci Applicat Int Corp, Hampton, VA 23666 USA. Univ Liege, Inst Astrophys & Geophys, B-4000 Liege, Belgium. RP Rinsland, CP (reprint author), NASA, Langley Res Ctr, 21 Langley Bldg,Mail Stop 402, Hampton, VA 23681 USA. EM c.p.rinsland@larc.nasa.gov; dweisens@aer.com; m.k.ko@larc.nasa.gov; scott@aer.com; l.s.chiou@larc.nasa.gov; Emmanuel.Mahieu@ulg.ac.be; R.Zander@ulg.ac.be; demoulin@astro.ulg.ac.be RI Ko, Malcolm/D-5898-2015 NR 75 TC 25 Z9 26 U1 0 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 AUG 1 PY 2003 VL 108 IS D15 AR 4437 DI 10.1029/2002JD002965 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 710XA UT WOS:000184707100001 ER PT J AU Park, JS Choi, CK Kihm, KD Allen, JS AF Park, JS Choi, CK Kihm, KD Allen, JS TI Optically-sectioned micro PIV measurements using CLSM SO JOURNAL OF HEAT TRANSFER-TRANSACTIONS OF THE ASME LA English DT Article; Proceedings Paper CT International Mechanical Engineering Congress and Exposition of the American-Society-of-Mechanical-Engineers CY NOV 17-22, 2002 CL NEW ORLEANS, LOUISIANA SP Amer Soc Mech Engineers C1 Texas A&M Univ, College Stn, TX 77843 USA. NASA, Glenn Res Ctr, Cleveland, OH USA. RP Park, JS (reprint author), Texas A&M Univ, College Stn, TX 77843 USA. NR 0 TC 9 Z9 9 U1 0 U2 3 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA THREE PARK AVE, NEW YORK, NY 10016-5990 USA SN 0022-1481 J9 J HEAT TRANS-T ASME JI J. Heat Transf.-Trans. ASME PD AUG PY 2003 VL 125 IS 4 BP 542 EP 542 DI 10.1115/1.1617071 PG 1 WC Thermodynamics; Engineering, Mechanical SC Thermodynamics; Engineering GA 709DY UT WOS:000184610500002 ER PT J AU Lee, JY Cho, KI Song, IS Kim, CB Son, SY AF Lee, JY Cho, KI Song, IS Kim, CB Son, SY TI Microscale bubble nucleation from an artificial cavity in single microchannel SO JOURNAL OF HEAT TRANSFER-TRANSACTIONS OF THE ASME LA English DT Article; Proceedings Paper CT International Mechanical Engineering Congress and Exposition of the American-Society-of-Mechanical-Engineers CY NOV 17-22, 2002 CL NEW ORLEANS, LOUISIANA SP Amer Soc Mech Engineers C1 NASA, Glenn Res Ctr, Natl Ctr Micrograv Res, Cleveland, OH 44135 USA. RP Son, SY (reprint author), NASA, Glenn Res Ctr, Natl Ctr Micrograv Res, Cleveland, OH 44135 USA. NR 0 TC 3 Z9 4 U1 0 U2 1 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA THREE PARK AVE, NEW YORK, NY 10016-5990 USA SN 0022-1481 J9 J HEAT TRANS-T ASME JI J. Heat Transf.-Trans. ASME PD AUG PY 2003 VL 125 IS 4 BP 545 EP 545 DI 10.1115/1.1617074 PG 1 WC Thermodynamics; Engineering, Mechanical SC Thermodynamics; Engineering GA 709DY UT WOS:000184610500005 ER PT J AU Hebsur, MG Noebe, RD Revilock, DM AF Hebsur, MG Noebe, RD Revilock, DM TI Impact resistance of lightweight hybrid structures for gas turbine engine fan containment applications SO JOURNAL OF MATERIALS ENGINEERING AND PERFORMANCE LA English DT Article DE gas turbine engine; GLARE-5; hybrid structures; impact resistance ID PLATES AB The ballistic impact resistance of hybrid composite sandwich structures was evaluated with the ultimate goal of developing new materials or structures for potential gas turbine engine, fan containment applications. The sandwich structures investigated consisted of GLARE-5 (Aviation Equipment, Inc., Costa Mesa, CA) laminates as face sheets with lightweight cellular metallic materials such as honeycomb, foam, and lattice block as a core material. The impact resistance of these hybrid sandwich structures was compared with GLARE-5 laminates and 2024-T3 Al sheets, which were tested as a function of areal weight (material thickness). The GLARE-5 laminates exhibited comparable impact properties to that of 2024-T3 Al at low areal weights, even though there were significant differences in the static tensile properties of these materials. The GLARE-5, however, did have a greater ballistic limit than straight aluminum sheet at higher areal weights. Furthermore, there is up to a 25% advantage in ballistic limit for the GLARE-5/foam sandwich structures compared with straight 2024-T3 Al. But no advantage in ballistic limit was observed between any of the hybrid sandwich structures and thicker versions of GLARE-5. Recommendations for future work are provided, based on these preliminary data. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Hebsur, MG (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. NR 20 TC 8 Z9 8 U1 1 U2 10 PU ASM INTERNATIONAL PI MATERIALS PARK PA SUBSCRIPTIONS SPECIALIST CUSTOMER SERVICE, MATERIALS PARK, OH 44073-0002 USA SN 1059-9495 J9 J MATER ENG PERFORM JI J. Mater. Eng. Perform. PD AUG PY 2003 VL 12 IS 4 BP 470 EP 479 DI 10.1361/105994903770343033 PG 10 WC Materials Science, Multidisciplinary SC Materials Science GA 712RX UT WOS:000184811600017 ER PT J AU Penumadu, D Dutta, A Pharr, GM Files, B AF Penumadu, D Dutta, A Pharr, GM Files, B TI Mechanical properties of blended single-wall carbon nanotube composites SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID ELASTIC PROPERTIES; LOAD; STRENGTH; GROWTH AB The improvement in mechanical properties of blended nanocomposites prepared using a low-viscosity, liquid epoxy resin and purified single-wall carbon nanotubes (SWCNTs) was evaluated. The macroscopic tensile stress-strain behavior for hybrid materials made with varying amounts of SWCNT was determined and showed little improvement in the breaking tensile strength. The corresponding variations in modulus and hardness were obtained using nanoindentation considering time effects and showed quantifiable but modest improvements. The small changes in the observed stiffness and breaking strength of carbon nanotube composites is due to the formation of bundles and their curvy morphology. C1 Univ Tennessee, Dept Civil & Environm Engn, Knoxville, TN 37996 USA. Univ Tennessee, Dept Mat Sci & Engn, Knoxville, TN 37996 USA. NASA, Lyndon B Johnson Space Ctr, ES4 Mat & Proc Branch, Houston, TX 77058 USA. RP Penumadu, D (reprint author), Univ Tennessee, Dept Civil & Environm Engn, Knoxville, TN 37996 USA. NR 22 TC 52 Z9 54 U1 0 U2 10 PU MATERIALS RESEARCH SOCIETY PI WARRENDALE PA 506 KEYSTONE DR, WARRENDALE, PA 15086 USA SN 0884-2914 J9 J MATER RES JI J. Mater. Res. PD AUG PY 2003 VL 18 IS 8 BP 1849 EP 1853 DI 10.1557/JMR.2003.0258 PG 5 WC Materials Science, Multidisciplinary SC Materials Science GA 709EF UT WOS:000184611200019 ER PT J AU Srivastava, D Menon, M Ajayan, PM AF Srivastava, D Menon, M Ajayan, PM TI Branched carbon nanotube junctions predicted by computational nanotechnology and fabricated through nanowelding SO JOURNAL OF NANOPARTICLE RESEARCH LA English DT Article DE computational nanotechnology; carbon nanotube junctions; molecular electronics; quantum mechanics; numerical simulations ID ELECTRONIC-PROPERTIES; DEVICES AB Examples of progress in fabricating branched multi-terminal multi-wall and single-wall carbon nanotube junctions as predicted by nanotechnology simulations, using template growth and nanowelding techniques, respectively, have been briefly reviewed in this report. It is argued that similar general progress in computational nanotechnology-driven fabrication of applications in other nanomaterials such as nanotubes, fullerenes, nanowires, quantum dots, DNA molecules, and nanoparticle-based systems and devices are also feasible. This is because, at nanometer length scale, system sizes have shrunk sufficiently small such that it is feasible to simulate the structural, stability, and physical and chemical characteristics with very high accuracy predictive simulations. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ Kentucky, Dept Phys, Lexington, KY 40506 USA. Univ Kentucky, Ctr Computat Sci, Lexington, KY 40506 USA. Rensselaer Polytech Inst, Dept Mat Sci & Engn, Troy, NY 12180 USA. RP Srivastava, D (reprint author), NASA, Ames Res Ctr, MS 229-1, Moffett Field, CA 94035 USA. NR 26 TC 9 Z9 11 U1 0 U2 6 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 1388-0764 J9 J NANOPART RES JI J. Nanopart. Res. PD AUG PY 2003 VL 5 IS 3-4 BP 395 EP 400 DI 10.1023/A:1025579730847 PG 6 WC Chemistry, Multidisciplinary; Nanoscience & Nanotechnology; Materials Science, Multidisciplinary SC Chemistry; Science & Technology - Other Topics; Materials Science GA 717QA UT WOS:000185099800020 ER PT J AU Chai, F Jiang, MS Barber, RT Dugdale, RC Chao, Y AF Chai, F Jiang, MS Barber, RT Dugdale, RC Chao, Y TI Interdecadal variation of the transition zone chlorophyll front: A physical-biological model simulation between 1960 and 1990 SO JOURNAL OF OCEANOGRAPHY LA English DT Article DE Pacific decadal; variability; physical-biological modeling; chlorophyll front; Pacific Ocean; model simulation ID SUB-ARCTIC PACIFIC; GENERAL-CIRCULATION MODEL; CENTRAL EQUATORIAL PACIFIC; NORTH PACIFIC; ECOSYSTEM MODEL; PHYTOPLANKTON GROWTH; PRIMARY PRODUCTIVITY; SUBTROPICAL GYRE; IRON LIMITATION; MIXED-LAYER AB The interdecadal climate variability affects marine ecosystems in both the subtropical and subarctic gyres, consequently the position of the Transition Zone Chlorophyll Front (TZCF). A three-dimensional physical-biological model has been used to study interdecadal variation of the TZCF using a retrospective analysis of a 30-year (1960-1990) model simulation. The physical-biological model is forced with the monthly mean heat flux and surface wind stress from the COADS. The modeled winter mixed layer depth (MLD) shows the largest increase between 30degreesN and 40degreesN in the central North Pacific, with a value of 40-60% higher during 1979-90 relative to 1964-75 values. The winter Ekman pumping velocity difference between 1979-90 and 196475 shows the largest increase located between 30degreesN and 45degreesN in the central and eastern North Pacific. The modeled winter surface nitrate difference between 1979-90 and 1964-75 shows increase in the latitudinal band between 30degreesN and 45degreesN from the west to the east (135degreesE-135degreesW), the modeled nitrate concentration is about 10 to 50% higher during the period of 1979-90 relative to 1964-75 values depending upon locations. The increase in the winter surface nitrate concentration during 1979-90 is caused by a combination of the winter MLD increase and the winter Ekman pumping enhancement. The modeled nitrate concentration increase after 1976-77 enhances primary productivity in the central North Pacific. Enhanced primary productivity after the 1976-77 climatic shift contributes higher phytoplankton biomass and therefore elevates chlorophyll level in the central North Pacific. Increase in the modeled chlorophyll expand the chlorophyll transitional zone and push the TZCF equatorward. C1 Univ Maine, Sch Marine Sci, Orono, ME 04469 USA. Duke Univ, NSOE Marine Lab, Beaufort, NC 28516 USA. San Francisco State Univ, Romberg Tiburon Ctr, Tiburon, CA 94920 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Chai, F (reprint author), Univ Maine, Sch Marine Sci, 5471 Libby Hall, Orono, ME 04469 USA. NR 68 TC 57 Z9 58 U1 0 U2 7 PU TERRA SCIENTIFIC PUBL CO PI TOKYO PA 2003 SANSEI JIYUGAOKA HAIMU, 5-27-19 OKUSAWA, SETAGAYA-KU, TOKYO, 158-0083, JAPAN SN 0916-8370 J9 J OCEANOGR JI J. Oceanogr. PD AUG PY 2003 VL 59 IS 4 BP 461 EP 475 DI 10.1023/A:1025540632491 PG 15 WC Oceanography SC Oceanography GA 696BY UT WOS:000183866500007 ER PT J AU Moon, IJ Ginis, I Hara, T Tolman, HL Wright, CW Walsh, EJ AF Moon, IJ Ginis, I Hara, T Tolman, HL Wright, CW Walsh, EJ TI Numerical simulation of sea surface directional wave spectra under hurricane wind forcing SO JOURNAL OF PHYSICAL OCEANOGRAPHY LA English DT Article ID SPATIAL VARIATION; WAM MODEL; OCEAN; STORM; LANDFALL; RADAR AB Numerical simulation of sea surface directional wave spectra under hurricane wind forcing was carried out using a high-resolution wave model. The simulation was run for four days as Hurricane Bonnie ( 1998) approached the U. S. East Coast. The results are compared with buoy observations and NASA Scanning Radar Altimeter (SRA) data, which were obtained on 24 August 1998 in the open ocean and on 26 August when the storm was approaching the shore. The simulated significant wave height in the open ocean reached 14 m, agreeing well with the SRA and buoy observations. It gradually decreased as the hurricane approached the shore. In the open ocean, the dominant wavelength and wave direction in all four quadrants relative to the storm center were simulated very accurately. For the landfall case, however, the simulated dominant wavelength displays noticeable overestimation because the wave model cannot properly simulate shoaling processes. Direct comparison of the model and SRA directional spectra in all four quadrants of the hurricane shows excellent agreement in general. In some cases, the model produces smoother spectra with narrower directional spreading than do the observations. The spatial characteristics of the spectra depend on the relative position from the hurricane center, the hurricane translation speed, and bathymetry. Attempts are made to provide simple explanations for the misalignment between local wind and wave directions and for the effect of hurricane translation speed on wave spectra. C1 Univ Rhode Isl, Grad Sch Oceanog, Narragansett, RI 02882 USA. GSO, SAIC, Camp Springs, MD USA. NCEP Environm Modeling Ctr, Camp Springs, MD USA. NASA, Goddard Space Flight Ctr, Wallops Flight Facil, Wallops Isl, VA 23337 USA. RP Moon, IJ (reprint author), Univ Rhode Isl, Grad Sch Oceanog, Narragansett, RI 02882 USA. RI Hara, Tetsu/G-9779-2011 NR 27 TC 64 Z9 70 U1 2 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 AUG PY 2003 VL 33 IS 8 BP 1680 EP 1706 DI 10.1175/2410.1 PG 27 WC Oceanography SC Oceanography GA 711QW UT WOS:000184753400010 ER PT J AU Fox, DS Opila, EJ Nguyen, QN Humphrey, DL Lewton, SM AF Fox, DS Opila, EJ Nguyen, QN Humphrey, DL Lewton, SM TI Paralinear oxidation of silicon nitride in a water-vapor/oxygen environment SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Article; Proceedings Paper CT Symposium on Water Vapor Effects on Oxidation of High-Temperature Materials held at the 131st Annual Meeting of the Minerals-Metals-and-Materials-Society CY FEB 18-20, 2002 CL SEATTLE, WASHINGTON SP Minerals, Met & Mat Soc ID SIO2 SCALE VOLATILITY; HIGH-TEMPERATURE OXIDATION; COMBUSTION CONDITIONS; VAPOR; KINETICS; CARBIDE; CERAMICS; RECESSION; BEHAVIOR; SI3N4 AB Three Si3N4 materials were exposed to dry oxygen flowing at 0.44 cm/s at temperatures between 1200degrees and 1400degreesC. Weight change was measured using a continuously recording microbalance. Parabolic kinetics were observed. When the same materials were exposed to a 50% H2O-50% O-2 gas mixture flowing at 4.4 cm/s, all three types exhibited paralinear kinetics. The material was oxidized by water vapor to form solid SiO2. The protective SiO2 was in turn volatilized by water vapor to form primarily gaseous Si(OH)(4). Nonlinear least-squares analysis and a paralinear kinetic model were used to determine parabolic and linear rate constants from the kinetic data. Volatilization of the protective SiO2 scale could result in accelerated consumption of Si3N4. Recession rates under conditions more representative of actual combustors were compared with the furnace data. C1 NASA, John H Glenn Res Ctr Lewis Field, Cleveland, OH 44135 USA. NR 32 TC 44 Z9 45 U1 0 U2 4 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, PO BOX 6136, WESTERVILLE, OH 43086-6136 USA SN 0002-7820 J9 J AM CERAM SOC JI J. Am. Ceram. Soc. PD AUG PY 2003 VL 86 IS 8 BP 1256 EP 1261 PG 6 WC Materials Science, Ceramics SC Materials Science GA 713YN UT WOS:000184885700004 ER PT J AU Opila, EJ Robinson, RC Fox, DS Wenglarz, RA Ferber, MK AF Opila, EJ Robinson, RC Fox, DS Wenglarz, RA Ferber, MK TI Additive effects onSi(3)N(4) oxidation/volatilization in water vapor SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Article; Proceedings Paper CT Symposium on Water Vapor Effects on Oxidation of High-Temperature Materials held at the 131st Annual Meeting of the Minerals-Metals-and-Materials-Society CY FEB 18-20, 2002 CL SEATTLE, WASHINGTON SP Minerals, Met & Mat Soc ID SIO2 SCALE VOLATILITY; PRESSED SILICON-NITRIDE; COMBUSTION CONDITIONS; OXIDATION; RECESSION; KINETICS; CARBIDE; MODEL AB Two commercially available additive-containing silicon nitride materials were exposed in four environments which ranged in severity from dry oxygen at 1 atm pressure, and low gas velocity, to an actual turbine engine. Oxidation and volatilization kinetics were monitored at temperatures ranging from 1066degrees to 1400degreesC. The main purpose of this paper is to examine the surface oxide morphology resulting from the exposures. It was found that the material surface was enriched in rare-earth silicate phases in combustion environments when compared with the oxides formed on materials exposed in dry oxygen. However, the in situ formation of rare-earth disilicate phases offered little additional protection from the volatilization of silica observed in combustion environments. It was concluded that externally applied environmental barrier coatings are needed to protect additive-containing silicon nitride materials from volatilization reactions in combustion environments. C1 Cleveland State Univ, Cleveland, OH 44115 USA. QSS Grp Inc, Cleveland, OH 44135 USA. S Carolina Inst Energy Studies, Clemson, SC 29634 USA. Oak Ridge Natl Lab, Oak Ridge, TN 37830 USA. NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. NR 28 TC 38 Z9 38 U1 1 U2 2 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, PO BOX 6136, WESTERVILLE, OH 43086-6136 USA SN 0002-7820 J9 J AM CERAM SOC JI J. Am. Ceram. Soc. PD AUG PY 2003 VL 86 IS 8 BP 1262 EP 1271 PG 10 WC Materials Science, Ceramics SC Materials Science GA 713YN UT WOS:000184885700005 ER PT J AU Lee, KN Fox, DS Eldridge, JI Zhu, DM Robinson, RC Bansal, NP Miller, RA AF Lee, KN Fox, DS Eldridge, JI Zhu, DM Robinson, RC Bansal, NP Miller, RA TI Upper temperature limit of environmental barrier coatings based on mullite and BSAS SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Article; Proceedings Paper CT Symposium on Water Vapor Effects on Oxidation of High-Temperature Materials held at the 131st Annual Meeting of the Minerals-Metals-and-Materials-Society CY FEB 18-20, 2002 CL SEATTLE, WASHINGTON SP Minerals, Met & Mat Soc ID SIO2 SCALE VOLATILITY; SILICON-CARBIDE; CERAMICS; DURABILITY; OXIDATION; RECESSION AB Current state-of-the-art environmental barrier coatings (EBCs) for Si-based ceramics consist of three layers: a silicon bond coat, an intermediate mullite (3Al(2)O(3).SiO2) or mullite + SAS ((1 -x)BaO.xSrO.Al2O3.2SiO(2), 0 less than or equal to x less than or equal to 1) layer, and a BSAS top coat. Areas of concern for long-term durability are environmental durability, chemical compatibility, volatility, phase stability, and thermal conductivity. Variants of this family of EBC were applied onto monolithic SiC and melt-infiltrated SiC/SiC composites. Reaction between BSAS and silica results in a low-melting (similar to1300degreesC) glass, which can cause the spallation of the EBC. At temperatures greater than similar to1400degreesC BSAS suffers significant recession via volatilization in water-vapor-containing atmospheres. Both reactions can be EBC life-limiting factors. BSAS undergoes a very sluggish phase transformation (hexagonal celsian to monoclinic celsian), the implications of which are not fully understood at this point. Initial rapid increase in thermal conductivity at temperatures as low as 1300degreesC indicates the sintering of EBC. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. NR 19 TC 135 Z9 144 U1 12 U2 66 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, PO BOX 6136, WESTERVILLE, OH 43086-6136 USA SN 0002-7820 J9 J AM CERAM SOC JI J. Am. Ceram. Soc. PD AUG PY 2003 VL 86 IS 8 BP 1299 EP 1306 PG 8 WC Materials Science, Ceramics SC Materials Science GA 713YN UT WOS:000184885700009 ER PT J AU Anicich, VG Wilson, P McEwan, MJ AF Anicich, VG Wilson, P McEwan, MJ TI Termolecular ion-molecule reactions in Titan's atmosphere. IV. A search made at up to 1 micron in pure hydrocarbons SO JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY LA English DT Article ID ASSOCIATION REACTIONS; LOW-PRESSURE; FLOW TUBE; IONOSPHERE; CHEMISTRY; SYSTEM AB The results of a study of ion-molecule reactions occurring in pure methane, acetylene, ethylene, ethane, propyne, propene, propane, and diacetylene at pressures up to 40 microns of pressure are reported. A variety of experimental methods are used: The standard double resonance in an ICR, for determination of the precursor ions and the modulated double resonance ejection in an ICR, for the determination of the daughter ions. The FA-SIFT technique was used for validation and examination of termolecular reactions with rate coefficients that are less than 10(-26) cm(6) s(-1). An extensive database of reaction kinetics already exists for many of these reactions. The main point of this study was the determination of the accuracy of this database and to search for any missing reactions and reaction channels that may have been omitted from earlier investigations. A specific objective of this work was to extend the study to the highest pressures possible to find out if there were any important termolecular reaction channels occurring. A new approach was used here. In the pure hydrocarbon gases the mass spectra were followed as a function of the pressure changes of the gas. An initial guess was first made using the current literature as a source of the reaction kinetics that were expected. A model of the ion abundances was produced from the solution of the partial differential equations in terms of reaction rate coefficients and initial abundances. The experimental data was fitted to the model for all of the pressures by a least squares minimization to the reaction rate coefficients and initial abundances. The reaction rate coefficients obtained from the model were then compared to the literature values. Several new channels and reactions were discovered when the modeled fits were compared to the actual data. This is all explained in the text and the implications of these results are discussed for the Titan atmosphere. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Canterbury, Dept Chem, Christchurch 1, New Zealand. RP Anicich, VG (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,M-S 183-301, Pasadena, CA 91109 USA. NR 19 TC 19 Z9 19 U1 1 U2 7 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 1044-0305 J9 J AM SOC MASS SPECTR JI J. Am. Soc. Mass Spectrom. PD AUG PY 2003 VL 14 IS 8 BP 900 EP 915 DI 10.1016/S1044-0305(03)00218-6 PG 16 WC Chemistry, Analytical; Chemistry, Physical; Spectroscopy SC Chemistry; Spectroscopy GA 708MD UT WOS:000184570500010 PM 12892914 ER PT J AU Petersen, WA Cifelli, R Boccippio, DJ Rutledge, SA Fairall, C AF Petersen, WA Cifelli, R Boccippio, DJ Rutledge, SA Fairall, C TI Convection and easterly wave structures observed in the eastern Pacific warm pool during EPIC-2001 SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID SYNOPTIC-SCALE DISTURBANCES; INTERTROPICAL CONVERGENCE ZONE; TOGA COARE CONVECTION; AIR-SEA FLUXES; PHASE-III; DOPPLER RADAR; LIGHTNING OBSERVATIONS; BULK PARAMETERIZATION; TROPICAL CYCLOGENESIS; VERTICAL STRUCTURE AB During September - October 2001, the East Pacific Investigation of Climate Processes in the Coupled Ocean Atmosphere System (EPIC-2001) intertropical convergence zone (ITCZ) field campaign focused on studies of deep convection in the warm-pool region of the eastern Pacific. This study combines C-band Doppler radar, sounding, and surface heat flux data collected aboard the R/V Ronald H. Brown during EPIC to describe the kinematic and thermodynamic states of the ITCZ environment, together with tendencies in convective structure, lightning, rainfall, and surface heat fluxes as a function of 3-5-day easterly wave phase. Three easterly waves were observed at the location of the R/V Brown during EPIC-2001. Wind and thermodynamic data reveal that the wave trough axes exhibited positively correlated u and v winds, a slight westward phase tilt with height, and relatively strong ( weak) northeasterly tropospheric shear following the trough ( ridge) axis. Temperature and humidity perturbations exhibited mid- to upper-level cooling ( warming) and drying ( moistening) in the northerly ( trough and southerly) phase. At low levels, warming ( cooling) and moistening ( drying) occurred in the northerly ( southerly) phase. Composited radar, sounding, lightning, and surface heat flux observations suggest the following systematic behavior as a function of wave phase: zero to one-quarter wavelength ahead of ( behind) the wave trough in northerly ( southerly) flow, larger ( smaller) convective available potential energy ( CAPE), lower ( higher) convective inhibition (CIN), weaker ( stronger) tropospheric shear, larger ( smaller) convective rain fractions, higher ( lower) conditional mean rain rates, higher ( lower) lightning flash densities, and more ( less) robust convective vertical structure occurred. Latent and sensible heat fluxes reached a minimum in the northerly phase and then increased through the trough, reaching a peak during the ridge phase ( leading the peak in CAPE). Larger areas of light convective and stratiform rain and slightly larger (10%) area-averaged rain rates occurred in the vicinity of, and just behind, the trough axes in southerly and ridge flow. Importantly, the transition in convective structure observed across the trougth axis when considered with the relatively small change in area mean rain rates suggests the presence of a transition in the vertical structure of diabatic heating across the easterly waves examined. The inferred transition in heating structure is supported by radar-diagnosed divergence profiles that exhibit convective ( stratiform) characteristics ahead of ( behind) the trough. C1 Univ Alabama, NSSTC ESSC, Huntsville, AL 35899 USA. Colorado State Univ, Dept Atmospher Sci, Ft Collins, CO 80523 USA. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. NOAA, ETL, Boulder, CO USA. RP Petersen, WA (reprint author), Univ Alabama, NSSTC ESSC, Huntsville, AL 35899 USA. EM walt.petersen@msfc.nasa.gov NR 76 TC 46 Z9 46 U1 0 U2 6 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 AUG PY 2003 VL 60 IS 15 BP 1754 EP 1773 DI 10.1175/1520-0469(2003)060<1754:CAEWSO>2.0.CO;2 PG 20 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 704NX UT WOS:000184346700002 ER PT J AU Dean, BH Bowers, CW AF Dean, BH Bowers, CW TI Diversity selection for phase-diverse phase retrieval SO JOURNAL OF THE OPTICAL SOCIETY OF AMERICA A-OPTICS IMAGE SCIENCE AND VISION LA English DT Article ID SPACE-TELESCOPE; ADAPTIVE OPTICS; ALGORITHMS; ERROR AB Wavefront-sensing performance is assessed for focus-diverse phase retrieval as the aberration spatial frequency and the diversity defocus are varied. The analysis includes analytical predictions for optimal diversity values corresponding to the recovery of a dominant spatial-frequency component in the pupil. The calculation is shown to be consistent with the Cramer-Rao lower bound by considering a sensitivity analysis of the point-spread function to the spatial frequency being estimated. A maximum value of diversity defocus is also calculated, beyond which wavefront-sensing performance decreases as diversity defocus is increased. The results are shown to be consistent with the Talbot imaging phenomena, explaining multiple periodic regions of maximum and minimum contrast as a function of aberration spatial frequency and defocus. Wavefront-sensing performance for an iterative-transform phase-retrieval algorithm is also considered as diversity defocus and aberration spatial frequency are varied. C1 NASA, Goddard Space Flight Ctr, Design & Anal Grp, Opt Branch, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, UV Opt Astron Branch, Greenbelt, MD 20771 USA. RP Dean, BH (reprint author), NASA, Goddard Space Flight Ctr, Design & Anal Grp, Opt Branch, Code 551, Greenbelt, MD 20771 USA. NR 35 TC 37 Z9 38 U1 0 U2 3 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 0740-3232 J9 J OPT SOC AM A JI J. Opt. Soc. Am. A-Opt. Image Sci. Vis. PD AUG PY 2003 VL 20 IS 8 BP 1490 EP 1504 DI 10.1364/JOSAA.20.001490 PG 15 WC Optics SC Optics GA 706DB UT WOS:000184436100003 PM 12938905 ER PT J AU Grivel, JC Santoro, F Chen, S Faga, G Malnati, MS Ito, Y Margolis, L Lusso, P AF Grivel, JC Santoro, F Chen, S Faga, G Malnati, MS Ito, Y Margolis, L Lusso, P TI Pathogenic effects of human herpesvirus 6 in human lymphoid tissue ex vivo SO JOURNAL OF VIROLOGY LA English DT Article ID IMMUNODEFICIENCY-VIRUS TYPE-1; HUMAN HERPESVIRUS-6 INFECTION; MULTIPLE-SCLEROSIS; CXCR4-TROPIC HIV-1; DOWN-REGULATION; TROPISM; CELLS; HHV-6; CD4; HISTOCULTURES AB Human herpesvirus 6 (HHV-6) is a potentially immunosuppressive agent that has been suggested to act as a cofactor in the progression of human immunodeficiency virus disease. However, the lack of suitable experimental models has hampered the elucidation of the mechanisms of HHV-6-mediated immune suppression. Here, we used ex vivo lymphoid tissue to investigate the cellular tropism and pathogenic mechanisms of HHV-6. Viral strains belonging to both HHV-6 subgroups (A and B) were able to productively infect human tonsil tissue fragments in the absence of exogenous stimulation. The majority of viral antigen-expressing cells were CD4(+) T lymphocytes expressing a nonnaive phenotype, while CD8(+) T cells were efficiently infected only with HHV-6A. Accordingly, HHV-6A infection resulted in the depletion of both CD4(+) and CD8(+) T cells, whereas in HFUV-6B-infected tissue CD4(+) T cells were predominantly depleted. The expression of different cellular antigens was dramatically altered in HHV-6-infected tissues: whereas CD4 was upregulated, both CD46, which serves as a cellular receptor for HHV-6, and CD3 were downmodulated. However, CD3 downmodullation was restricted to infected cells, while the loss of CD46 expression was generalized. Moreover, HHV-6 infection markedly enhanced the production of the CC chemokine RANTES, whereas other cytokines and chemokines were only marginally affected. These results provide the first evidence, in a physiologically relevant study model, that HHV-6 can severely affect the physiology of secondary lymphoid organs through direct infection of T lymphocytes and modulation of key membrane receptors and chemokines. C1 San Raffaele Sci Inst, DIBIT, Unit Human Virol, Dept Biol & Technol Res, I-20132 Milan, Italy. Univ Cagliari, Dept Med Sci, I-09123 Cagliari, Italy. NICHHD, Lab Cellular & Mol Biophys, Bethesda, MD 20892 USA. NIH, NASA, Ctr 3 Dimens Tissue Culture, Bethesda, MD 20892 USA. RP Margolis, L (reprint author), San Raffaele Sci Inst, DIBIT, Unit Human Virol, Dept Biol & Technol Res, Via Olgettina 58, I-20132 Milan, Italy. NR 30 TC 59 Z9 61 U1 0 U2 5 PU AMER SOC MICROBIOLOGY PI WASHINGTON PA 1752 N ST NW, WASHINGTON, DC 20036-2904 USA SN 0022-538X J9 J VIROL JI J. Virol. PD AUG PY 2003 VL 77 IS 15 BP 8280 EP 8289 DI 10.1128/JVI.77.15.8280-8289.2003 PG 10 WC Virology SC Virology GA 702FP UT WOS:000184214300012 PM 12857897 ER PT J AU DellaCorte, C AF DellaCorte, C TI I see Tribology everywhere. Don't you? SO LUBRICATION ENGINEERING LA English DT Editorial Material C1 NASA, Glenn Res Ctr, Brookpark, OH 44142 USA. RP DellaCorte, C (reprint author), NASA, Glenn Res Ctr, Brookpark, OH 44142 USA. NR 0 TC 0 Z9 0 U1 2 U2 3 PU SOC TRIBOLOGISTS & LUBRICATION ENGINEERS PI PARK RIDGE PA 840 BUSSE HIGHWAY, PARK RIDGE, IL 60068 USA SN 0024-7154 J9 LUBR ENG JI Lubric. Eng. PD AUG PY 2003 VL 59 IS 8 BP 3 EP 3 PG 1 WC Engineering, Mechanical SC Engineering GA 710VJ UT WOS:000184703300001 ER PT J AU Moraru, L Keith, TG Dimofte, F Cioc, S Fleming, DP AF Moraru, L Keith, TG Dimofte, F Cioc, S Fleming, DP TI Dynamic modeling of a dual clearance squeeze film damper - Part I: Test rig and dynamic model with one damper SO LUBRICATION ENGINEERING LA English DT Article; Proceedings Paper CT 57th Annual Meeting of the Society-of-Tribologists-and-Lubrication-Engineers CY MAY 19-23, 2002 CL HOUSTON, TEXAS SP Soc Tribologists Lubricat Engn DE squeeze-film lubrication; dynamic modeling ID AIR ENTRAINMENT; COEFFICIENTS; CAVITATION AB This paper presents a description of a dual clearance squeeze film damper (SFD) test rig and a dynamic model of a single SFD. The purpose of a dual SFD is to provide protection at high levels of vibration, when conventional devices are no longer effective. An experimental facility was designed and built for the study of SFD behavior within mechanically controlled orbits. It can be used for both single and dual squeeze film dampers. In Part 1 of this paper, measured and computed responses are presented while operating as a single squeeze film device. Numerical and experimental results for undamped cases are presented, i.e., when no oil film is present in the damper. Subsequently, the effects of the oil film are considered. Good agreement was obtained between experimental data and predictions. C1 Univ Toledo, Toledo, OH 43606 USA. NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Moraru, L (reprint author), Univ Toledo, 2801 W Bancroft St, Toledo, OH 43606 USA. NR 23 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 0024-7154 J9 LUBR ENG JI Lubric. Eng. PD AUG PY 2003 VL 59 IS 8 BP 16 EP 24 PG 9 WC Engineering, Mechanical SC Engineering GA 710VJ UT WOS:000184703300003 ER PT J AU Moles, A Hale, N AF Moles, A Hale, N TI Use of physiological responses in Mytilus trossulus as integrative bioindicators of sewage pollution SO MARINE POLLUTION BULLETIN LA English DT Article DE Mytilus trossulus; Alaska; wastewater; sewage; parasite; outfalls ID PRINCE-WILLIAM-SOUND; VALDEZ CRUDE-OIL; PETROLEUM-HYDROCARBONS; MUSSELS; EDULIS; EXPOSURE; WATERS; SPILL AB Mussels, Mytilus trossulus (average shell length 43 +/- 0.8 mm), were sampled from a beach in Alaska that received untreated sewage for several years, a second beach adjacent to a secondary wastewater outfall, and two nearby reference beaches. Survival time in air, byssal thread production rate, and prevalence of trentatode parasites were determined for each group. Tolerances to aerial exposure was significantly lower (P < 0.05) at both sewage outfall sites than at the reference sites. Mussels exposed to untreated sewage produced fewer byssal threads and had a significantly higher prevalence of encysted trematodes than mussels from the other beaches, including the secondary wastewater site. Survival in air, byssal thread production, and trematode prevalence in mussels may be useful indicators in evaluating the longterm health of beaches exposed to sewage. Published by Elsevier Ltd. C1 NOAA, Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr, Auke Bay Lab, Juneau, AK 99801 USA. RP NOAA, Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr, Auke Bay Lab, Juneau, AK 99801 USA. EM adam.moles@noaa.gov NR 22 TC 15 Z9 15 U1 0 U2 6 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0025-326X EI 1879-3363 J9 MAR POLLUT BULL JI Mar. Pollut. Bull. PD AUG PY 2003 VL 46 IS 8 BP 954 EP 958 DI 10.1016/S0025-326X(03)00108-5 PG 5 WC Environmental Sciences; Marine & Freshwater Biology SC Environmental Sciences & Ecology; Marine & Freshwater Biology GA 715MC UT WOS:000184975300018 PM 12907188 ER PT J AU Duke, JC Cassino, CD Childers, BA Prosser, WH AF Duke, JC Cassino, CD Childers, BA Prosser, WH TI Characterization of an extrinsic Fabry-Perot interferometric acoustic emission sensor SO MATERIALS EVALUATION LA English DT Article DE acoustic emission; in plane displacement sensor; dynamic finite element model AB An extrinsic Fabry-Perot ititerferometric optical fiber acoustic emission sensor is characterized by comparing in plane displacements computed from detected signals for pencil lead breaks with dynamic finite element modeling predictions. C1 Virginia Tech, NDE Dev Lab, Blacksburg, VA 24061 USA. Luna Innovat Inc, Blacksburg, VA 24060 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Virginia Tech, NDE Dev Lab, ESM MC-0219, Blacksburg, VA 24061 USA. EM jcduke@vt.edu NR 13 TC 1 Z9 1 U1 0 U2 0 PU AMER SOC NONDESTRUCTIVE TEST PI COLUMBUS PA 1711 ARLINGATE LANE PO BOX 28518, COLUMBUS, OH 43228-0518 USA SN 0025-5327 J9 MATER EVAL JI Mater. Eval. PD AUG PY 2003 VL 61 IS 8 BP 935 EP 940 PG 6 WC Materials Science, Characterization & Testing SC Materials Science GA 709AW UT WOS:000184603400010 ER PT J AU Lewandowski, JJ Wesseling, P Prabhu, NS Larose, J Lerch, BA AF Lewandowski, JJ Wesseling, P Prabhu, NS Larose, J Lerch, BA TI Strength differential measurements in IN 718: Effects of superimposed pressure SO METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE LA English DT Article ID HYDROSTATIC-PRESSURE; VOLUME EXPANSION; DEFORMATION-BEHAVIOR; PLASTICITY THEORY; FLOW-STRESS; METALS; INCONEL-718; STEELS; ALLOYS C1 Univ Cambridge, Dept Mat Sci & Met, Cambridge CB2 3QZ, England. Case Western Reserve Univ, Dept Mat Sci & Engn, Cleveland, OH 44106 USA. Cessna Aircraft Co, Wichita, KS 67277 USA. Pratt & Whitney Canada Corp, Longueuil, PQ J4G 1A1, Canada. NASA, Glen Res Ctr, Cleveland, OH 44135 USA. RP Lewandowski, JJ (reprint author), Univ Cambridge, Dept Mat Sci & Met, Pembroke St, Cambridge CB2 3QZ, England. NR 25 TC 3 Z9 3 U1 1 U2 3 PU MINERALS METALS MATERIALS SOC PI WARRENDALE PA 184 THORN HILL RD, WARRENDALE, PA 15086 USA SN 1073-5623 J9 METALL MATER TRANS A JI Metall. Mater. Trans. A-Phys. Metall. Mater. Sci. PD AUG PY 2003 VL 34A IS 8 BP 1736 EP 1739 DI 10.1007/s11661-003-0319-2 PG 4 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 705MT UT WOS:000184399400017 ER PT J AU Hansen, FK Gorski, KM AF Hansen, FK Gorski, KM TI Fast cosmic microwave background power spectrum estimation of temperature and polarization with Gabor transforms SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE polarization; methods : data analysis; methods : statistical; techniques : image processing; cosmological parameters; cosmology : observations ID ANISOTROPIES; MAPS AB We extend the analysis of Gabor transforms on a cosmic microwave background temperature map to polarization. We study the temperature and polarization power spectra on the cut sky, the so-called pseudo-power spectra. The transformation kernels relating the full-sky polarization power spectra and the polarization pseudo-power spectra are found to be similar to the kernel for the temperature power spectrum. This fact is used to construct a fast power spectrum estimation algorithm using the pseudo-power spectrum of temperature and polarization as data vectors in a maximum-likelihood approach. Using the pseudo-power spectra as input to the likelihood analysis solves the problem of having to invert huge matrices, which makes the standard likelihood approach infeasible. C1 Univ Roma Tor Vergata, Dipartimento Fis, I-00133 Rome, Italy. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Warsaw Observ, PL-00478 Warsaw, Poland. RP Univ Roma Tor Vergata, Dipartimento Fis, Via Ric Sci 1, I-00133 Rome, Italy. EM frodekh@roma2.infn.it; krzysztof.m.gorski@jpl.nasa.gov NR 25 TC 28 Z9 28 U1 0 U2 0 PU OXFORD UNIV PRESS PI OXFORD PA GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND SN 0035-8711 EI 1365-2966 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD AUG 1 PY 2003 VL 343 IS 2 BP 559 EP 584 DI 10.1046/j.1365-8711.2003.06695.x PG 26 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 704HT UT WOS:000184334600027 ER PT J AU Farrah, D Afonso, J Efstathiou, A Rowan-Robinson, M Fox, M Clements, D AF Farrah, D Afonso, J Efstathiou, A Rowan-Robinson, M Fox, M Clements, D TI Starburst and AGN activity in ultraluminous infrared galaxies SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE galaxies : active; quasars : general; galaxies : Seyfert; galaxies : starburst; infrared : galaxies ID MASSIVE STAR-FORMATION; SPECTRAL ENERGY-DISTRIBUTIONS; X-RAY OBSERVATIONS; HUBBLE DEEP FIELD; IRAS GALAXIES; LUMINOUS GALAXIES; SEYFERT-GALAXIES; HIGH-REDSHIFT; MIDINFRARED OBSERVATIONS; OPTICAL SPECTROSCOPY AB We examine the power source of 41 local ultraluminous infrared galaxies (ULIRGs) using archival infrared (IR) and optical photometry. We fit the observed spectral energy distributions with starburst and active galactic nucleus (AGN) components, each component being drawn from a family of templates. We find that all of the sample require a starburst, whereas only half require an AGN. In 90 per cent of the sample the starburst provides over half the IR emission, with a mean fractional luminosity of 82 per cent. When combined with other galaxy samples we find that starburst and AGN luminosities correlate over six decades in IR luminosity, suggesting that a common factor governs both luminosities, plausibly the gas masses in the nuclear regions. We find no trend for increasing fractional AGN luminosity with increasing total luminosity, contrary to previous claims. We find that the mid-IR F (7.7) /C (7.7) line-continuum ratio is no indication of the starburst luminosity, or the fractional AGN luminosity, and therefore that F (7.7) /C (7.7) is not a reliable diagnostic of the power source in ULIRGs. The radio flux correlates with the starburst luminosity, but shows no correlation with the AGN luminosity, in line with previous results. We propose that the scatter in this correlation is due to a skewed starburst initial mass function and/or relic relativistic electrons from a previous starburst, rather than contamination from an obscured AGN. We show that most ULIRGs undergo multiple starbursts during their lifetime, and by inference that mergers between more than two galaxies may be common amongst ULIRGs. Our results support the evolutionary model for ULIRGs proposed by Farrah et al., where they can follow many different evolutionary paths of starburst and AGN activity in transforming merging spiral galaxies into elliptical galaxies, but that most do not go through an optical quasi-stellar object phase. The lower level of AGN activity in our local sample compared with z similar to 1 hyperluminous infrared galaxies implies that the two samples are distinct populations. We postulate that different galaxy formation processes at high z are responsible for this difference. C1 CALTECH, Jet Prop Lab, SIRTF Sci Ctr, Pasadena, CA 91125 USA. Observ Astron Lisboa, CAAUL, P-1349018 Lisbon, Portugal. Onsala Space Observ, S-43992 Onsala, Sweden. Cyprus Coll, Dept Comp Sci & Engn, CY-1516 Nicosia, Cyprus. Univ London Imperial Coll Sci Technol & Med, Blackett Lab, Astrophys Grp, London SW7 2BW, England. RP Farrah, D (reprint author), CALTECH, Jet Prop Lab, SIRTF Sci Ctr, 4800 Oak Grove Dr, Pasadena, CA 91125 USA. RI Afonso, Jose/B-5185-2013 OI Afonso, Jose/0000-0002-9149-2973 NR 99 TC 165 Z9 165 U1 1 U2 4 PU BLACKWELL PUBLISHING LTD PI OXFORD PA 9600 GARSINGTON RD, OXFORD OX4 2DG, OXON, ENGLAND SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD AUG 1 PY 2003 VL 343 IS 2 BP 585 EP 607 DI 10.1046/j.1365-8711.2003.06696.x PG 23 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 704HT UT WOS:000184334600028 ER PT J AU Snyder, GJ Lim, JR Huang, CK Fleurial, JP AF Snyder, GJ Lim, JR Huang, CK Fleurial, JP TI Thermoelectric microdevice fabricated by a MEMS-like electrochemical process SO NATURE MATERIALS LA English DT Article ID DEVICES C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM JSnyder@jpl.nasa.gov RI Snyder, G. Jeffrey/E-4453-2011; Snyder, G/I-2263-2015 OI Snyder, G. Jeffrey/0000-0003-1414-8682; NR 16 TC 214 Z9 218 U1 10 U2 97 PU NATURE PUBLISHING GROUP PI LONDON PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 1476-1122 EI 1476-4660 J9 NAT MATER JI Nat. Mater. PD AUG PY 2003 VL 2 IS 8 BP 528 EP 531 DI 10.1038/nmat943 PG 4 WC Chemistry, Physical; Materials Science, Multidisciplinary; Physics, Applied; Physics, Condensed Matter SC Chemistry; Materials Science; Physics GA 710NW UT WOS:000184687200012 PM 12883550 ER PT J AU Gallaway, BJ Cole, JG Martin, LR Nance, JM Longnecker, M AF Gallaway, BJ Cole, JG Martin, LR Nance, JM Longnecker, M TI An evaluation of an electronic logbook as a more accurate method of estimating spatial patterns of trawling effort and bycatch in the Gulf of Mexico shrimp fishery SO NORTH AMERICAN JOURNAL OF FISHERIES MANAGEMENT LA English DT Article AB Penaeid shrimp trawling effort in the Gulf of Mexico is not measured directly but is estimated from landings and interview data gathered by port agents of the National Marine Fisheries Service (NMFS). The total pounds landed from each trip are assigned to one or more of the 219 statistical area-depth zone cells for which a catch rate (pounds per nominal day fished or catch per unit effort [CPUE]) is also obtained. Each month, the total landings in pounds for each cell are divided by the CPUE of the cell to determine effort or days fished. These values are summed across all cells and months to provide an estimate of total effort. The accuracy of total effort estimates is directly proportional to the accuracy of the landings allocations and estimated CPUE values. It has been assumed that allocation errors are random and that directional bias is negligible. In a previous paper, we described an electronic logbook (ELB) that enables accurate measurement of the spatial patterns of fishing effort. Herein, we provide comparisons of actual areas fished, pounds landed, and catch rates as measured with ELBs to the corresponding estimates made by NMFS port agents. The results show that directional bias occurs and that CPUE is often underestimated. Based on 135 trip comparisons, midshelf effort in 2000 was greatly overestimated, whereas nearshore and deepwater effort was substantially underestimated. If our effort results are representative, present estimates of the bycatch of midshelf species may therefore be greatly overestimated, whereas the converse may be true for nearshore and deepwater species. We suggest that a cooperative program involving both NMFS and industry should be implemented based on ELB technology and the port agent network to obtain more precise and accurate estimates of shrimp trawling effort with minimal impact on the fishers. C1 LGL Ecol Res Associates Inc, Bryan, TX 77801 USA. Natl Marine Fisheries Serv, Galveston Lab, Galveston, TX 77551 USA. Texas A&M Univ, Dept Stat, College Stn, TX 77843 USA. RP Gallaway, BJ (reprint author), LGL Ecol Res Associates Inc, 1410 Cavitt St, Bryan, TX 77801 USA. EM bgallaway@lgl.com NR 33 TC 16 Z9 16 U1 0 U2 1 PU TAYLOR & FRANCIS INC PI PHILADELPHIA PA 325 CHESTNUT ST, SUITE 800, PHILADELPHIA, PA 19106 USA SN 0275-5947 J9 N AM J FISH MANAGE JI North Am. J. Fish Manage. PD AUG PY 2003 VL 23 IS 3 BP 787 EP 809 DI 10.1577/M02-105 PG 23 WC Fisheries SC Fisheries GA 717VN UT WOS:000185111600013 ER PT J AU Kiefer, RL Anderson, RA Kim, MHY Thibeault, SA AF Kiefer, RL Anderson, RA Kim, MHY Thibeault, SA TI Modified polymeric materials for durability in the atomic oxygen space environment SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 5th International Symposium on Ionizing Radiation and Polymers (IRaP 2002) CY SEP 21-26, 2002 CL ST ADELE, CANADA SP Rech, Sci & Technol Quebec, Ecole Polytech Montreal, DSM DRECAM CEA/Saclay, IOM, IAEA Vienna, Grp COGETEFI, CTT Grp, GEX Corp, Nissin NHV Amer Inc, IBA, Promerus DE polymer films; additives; atomic oxygen; organometallics AB Organometallic compounds have been incorporated into organic polymers to improve their durability to the environment of the low earth orbit (LEO), particularly their resistance to erosion by atomic oxygen (AO). Bis(triphenyltin) oxide (BTO) was added to a thermoplastic polyetherimide, Ultem, and exposed on the Mir space station. The addition of the BTO to Ultem significantly reduced the mass loss in LEO. Aluminum acetylacetonate was added to a thermoset, PMDA-ODA polyimide. that is currently deployed on the International Space Station. Two films are placed in the ram direction exposed to AO and space radiation. Three films are placed in the wake direction and are exposed to space radiation but not AO. The doped films show superior resistance to AO. (C) 2003 Elsevier B.V. All rights reserved. C1 Coll William & Mary, Dept Chem, Williamsburg, VA 23187 USA. NASA, Langley Res Ctr, Adv Mat & Proc Branch, Hampton, VA 23681 USA. RP Kiefer, RL (reprint author), Coll William & Mary, Dept Chem, POB 8795, Williamsburg, VA 23187 USA. OI Kim, Myung-Hee/0000-0001-5575-6858 NR 5 TC 16 Z9 18 U1 0 U2 10 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 AUG PY 2003 VL 208 BP 300 EP 302 DI 10.1016/S0168-583X(03)00665-7 PG 3 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 707LT UT WOS:000184512700052 ER PT J AU Frederickson, AR Benson, CE Bockman, JF AF Frederickson, AR Benson, CE Bockman, JF TI Measurement of charge storage and leakage in polyimides SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS LA English DT Article; Proceedings Paper CT 5th International Symposium on Ionizing Radiation and Polymers (IRaP 2002) CY SEP 21-26, 2002 CL ST ADELE, CANADA SP Rech, Sci & Technol Quebec, Ecole Polytech Montreal, DSM DRECAM CEA/Saclay, IOM, IAEA Vienna, Grp COGETEFI, CTT Grp, GEX Corp, Nissin NHV Amer Inc, IBA, Promerus DE resistivity; polyimide; charge storage; irradiation; polarization; dielectric AB Resistivity and electric charge storage properties of LaRC-SI and Kapton polyimide samples were studied in a dark evacuated environment, both before and after 50 kGy cobalt-60 gamma irradiation. In different tests, slow electrons, and 4 keV electrons were used to charge surfaces of 50 mum polyimide to about 500 V while the opposite surfaces were copper metalized and grounded. The subsequent decay of surface voltage can be interpreted as a current through the resistivity of the dielectric. The same samples tested by classical ASTM and IEC methods provided resistivities of order 1E16 Omegacm, but when tested by our evacuated charge decay method the resistivity was 5E19-5E20 Omegacm or more. Charging with low energy electrons produced resistivity data reasonably similar to that produced by charging with 4 keV electron beams. The gamma irradiation, followed by one month of rest under no bias, reduced the resistivity by a factor of 2 in both materials. Raising temperature from the normal 20-50 degreesC reduced the resistivity in Kapton, but the reduction was not observable in the LaRC-SI material. Even after 20 days of "constant-bias" the rate of fractional charge loss continued to decline indicating that polarization current rather than ideal resistivity may be the cause of most voltage decay, and that the true resistivity is higher than the values determined here, and much higher by several orders of magnitude than the values determined in classical ASTM and IEC test procedures. (C) 2003 Elsevier B.V. All rights reserved. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. NASA, Langley Res Ctr, Hampton, VA USA. RP Frederickson, AR (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 11 TC 24 Z9 28 U1 2 U2 4 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 AUG PY 2003 VL 208 BP 454 EP 460 DI 10.1016/S0168-583X(03)00885-1 PG 7 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 707LT UT WOS:000184512700080 ER PT J AU DelBalzo, DR Schultz, JR Earle, MD AF DelBalzo, DR Schultz, JR Earle, MD TI Stochastic time-series simulation of wave parameters using ship observations SO OCEAN ENGINEERING LA English DT Article DE ocean waves; ship observations; wave data; wave simulations ID SEA-STATE; BUOYS AB A stochastic simulation technique was used with ship wave observations, which form the largest world-wide data base of wave information. Twenty years of wave parameter (height, period, and direction) observations from the Comprehensive Ocean-Atmosphere Data Set (COADS) were used as the input data. Simulations were compared to four years of wave parameters from a National Data Buoy Center (NDBC) data buoy near Monterey Bay, CA. The comparisons are satisfactory with differences mainly caused by biases between ship observations and buoy data. The stochastic simulation technique is attractive because it is computationally efficient and few decisions are required for its application. The applied techniques can be employed with global COADS data to simulate wave conditions at many world-wide locations where measurements and hindcasts by computer models do not exist. Published by Elsevier Science Ltd. C1 USN, Res Lab, Stennis Space Ctr, Stennis Space Ctr, MS 39529 USA. Boeing Autometr Inc, Springfield, VA 22153 USA. Neptune Sci Inc, Slidell, LA 70461 USA. RP DelBalzo, DR (reprint author), USN, Res Lab, Stennis Space Ctr, Code 7183, Stennis Space Ctr, MS 39529 USA. NR 25 TC 8 Z9 8 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0029-8018 J9 OCEAN ENG JI Ocean Eng. PD AUG PY 2003 VL 30 IS 11 BP 1417 EP 1432 DI 10.1016/S0029-8018(02)00120-8 PG 16 WC Engineering, Marine; Engineering, Civil; Engineering, Ocean; Oceanography SC Engineering; Oceanography GA 669NT UT WOS:000182357900005 ER PT J AU Kok, P Williams, CP Dowling, JP AF Kok, P Williams, CP Dowling, JP TI Construction of a quantum repeater with linear optics SO PHYSICAL REVIEW A LA English DT Article ID ENTANGLEMENT PURIFICATION; TELEPORTATION; PHOTONS; COMMUNICATION; CHANNELS; DOT AB We study the mechanism and complexity of an efficient quantum repeater, employing double-photon guns, for long-distance optical quantum communication. The guns create polarization-entangled photon pairs on demand. One such source might be a semiconducter quantum dot, which has the distinct advantage over parametric down-conversion that the probability of creating a photon pair is close to 1, while the probability of creating multiple pairs vanishes. The swapping and purifying components are implemented by polarizing beam splitters and probabilistic optical controlled-NOT gates. We also show that the bottleneck in the efficiency of this repeater is due to detector losses. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP CALTECH, Jet Prop Lab, Mail Stop 126-347,4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM Pieter.Kok@jpl.nasa.gov RI Kok, Pieter/B-1658-2010; DOWLING, JONATHAN/L-2749-2013 NR 21 TC 25 Z9 25 U1 0 U2 3 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2469-9926 EI 2469-9934 J9 PHYS REV A JI Phys. Rev. A PD AUG PY 2003 VL 68 IS 2 AR 022301 DI 10.1103/PhysRevA.68.022301 PG 5 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 719FC UT WOS:000185192100019 ER PT J AU Georgieva, E Kim, YS AF Georgieva, E Kim, YS TI Slide-rule-like property of Wigner's little groups and cyclic S matrices for multilayer optics SO PHYSICAL REVIEW E LA English DT Article ID LORENTZ TRANSFORMATIONS; SPECIAL RELATIVITY AB It is noted that 2x2 "S" matrices in multilayer optics can be represented by the Sp(2) group whose algebraic property is the same as the group of Lorentz transformations applicable to two spacelike and one timelike dimensions. It is also noted that Wigner's little groups have a slide-rule-like property that allows us to perform multiplications by additions. It is shown that these two mathematical properties lead to a cyclic representation of the S matrix for multilayer optics, as in the case of ABCD matrices for laser cavities. It is therefore possible to write the N-layer S matrix as a multiplication of the N single-layer S matrices resulting in the same mathematical expression with one of the parameters multiplied by N. In addition, it is noted, as in the case of lens optics, that multilayer optics can serve as an analog computer for the contraction of Wigner's little groups for internal space-time symmetries of relativistic particles. C1 Sci Syst & Applicat Inc, Lanham, MD 20771 USA. NASA, Goddard Space Flight Ctr, Laser & Electroopt Branch, Greenbelt, MD 20771 USA. Univ Maryland, Dept Phys, College Pk, MD 20742 USA. RP Sci Syst & Applicat Inc, Lanham, MD 20771 USA. EM egeorgie@pop500.gsfc.nasa.gov; yskim@physics.umd.edu NR 15 TC 13 Z9 15 U1 0 U2 0 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2470-0045 EI 2470-0053 J9 PHYS REV E JI Phys. Rev. E PD AUG PY 2003 VL 68 IS 2 AR 026606 DI 10.1103/PhysRevE.68.026606 PN 2 PG 7 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA 719GC UT WOS:000185194400100 PM 14525132 ER PT J AU Pruett, CD Gatski, TB Grosch, CE Thacker, WD AF Pruett, CD Gatski, TB Grosch, CE Thacker, WD TI The temporally filtered Navier-Stokes equations: Properties of the residual stress SO PHYSICS OF FLUIDS LA English DT Article ID LARGE-EDDY SIMULATION; SUBGRID-SCALE MODELS; TURBULENCE; INVARIANCE AB Recent interest in the development of a unifying framework among direct numerical simulations, large-eddy simulations, and statistically averaged formulations of the Navier-Stokes equations, provides the motivation for the present paper. Toward that goal, the properties of the residual (subgrid-scale) stress of the temporally filtered Navier-Stokes equations are carefully examined. This includes the frame-invariance properties of the filtered equations and the resulting residual stress. Causal time-domain filters, parametrized by a temporal filter width 0<&UDelta;0, the residual stress vanishes, in which case the Navier-Stokes equations are recovered from the temporally filtered equations. Alternately, in the limit Delta-->infinity, the residual stress is equivalent to the long-time averaged stress, and the Reynolds-averaged Navier-Stokes equations are recovered from the temporally filtered equations. The predicted behavior at the asymptotic limits of filter width is further validated by numerical simulations of the temporally filtered forced, viscous Burger's equation. Finally, finite filter widths are also considered, and both a priori and a posteriori analyses of temporal similarity and temporal approximate deconvolution models of the residual stress are conducted for the model problem. (C) 2003 American Institute of Physics. C1 James Madison Univ, Dept Math & Stat, Harrisonburg, VA 22807 USA. NASA, Computat Modeling & Simulat Branch, Langley Res Ctr, Hampton, VA 23681 USA. Old Dominion Univ, Dept Ocean Earth & Atmospher Sci, Norfolk, VA 23529 USA. Old Dominion Univ, Dept Comp Sci, Norfolk, VA 23529 USA. St Louis Univ, Parks Coll, Dept Phys, St Louis, MO 63156 USA. RP Pruett, CD (reprint author), James Madison Univ, Dept Math & Stat, Harrisonburg, VA 22807 USA. NR 22 TC 30 Z9 30 U1 0 U2 6 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 1070-6631 J9 PHYS FLUIDS JI Phys. Fluids PD AUG PY 2003 VL 15 IS 8 BP 2127 EP 2140 DI 10.1063/1.1582858 PG 14 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA 700GK UT WOS:000184104100007 ER PT J AU Dorelli, JC AF Dorelli, JC TI Effects of Hall electric fields on the saturation of forced antiparallel magnetic field merging SO PHYSICS OF PLASMAS LA English DT Article ID PILE-UP RECONNECTION; CURRENT SHEETS; PRESSURE LIMITATIONS; ENERGY-RELEASE; FLOWS AB The role of Hall electric fields in flux pile-up antiparallel magnetic field merging is addressed. Analytical solutions of the resistive Hall magnetohydrodynarnics (Hall-MHD) equations are obtained, describing stagnation point flows in a thin current sheet. The stagnation point flow solutions explain a number of interesting effects observed in two-dimensional resistive Hall-MHD simulations of forced magnetic reconnection. In particular, when Hall electric fields are important within the current sheet, less pile-up of magnetic energy is required upstream of the current sheet to support a given reconnection electric field. Fast electron flows transport magnetic flux into the diffusion layer without requiring a compensating drop in plasma pressure upstream of the current sheet. The maximum flux pile-up merging rate allowed by the external plasma pressure becomes independent of the Lundquist number, scaling like the square root of the ratio of the ion inertial length to the spatial scale of the stagnation point flow. Thus, Hall electric fields provide a possible solution to the problem of flux pile-up saturation in two-dimensional, resistive MHD models of forced magnetic reconnection. (C) 2003 American Institute of Physics. C1 NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Electrodynam Branch, Greenbelt, MD 20771 USA. RP Dorelli, JC (reprint author), NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Electrodynam Branch, Greenbelt, MD 20771 USA. RI Dorelli, John/C-9488-2012 NR 22 TC 31 Z9 31 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 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD AUG PY 2003 VL 10 IS 8 BP 3309 EP 3314 DI 10.1063/1.1589007 PG 6 WC Physics, Fluids & Plasmas SC Physics GA 707CL UT WOS:000184491800030 ER PT J AU Kossacki, KJ Markiewicz, WJ Smith, MD AF Kossacki, KJ Markiewicz, WJ Smith, MD TI Surface temperature of Martian regolith with polygonal features: influence of the subsurface water ice SO PLANETARY AND SPACE SCIENCE LA English DT Article DE Mars; surface; water; polar ID SOUTH POLAR-CAP; CO2 ICE; MARS; REGION; TES AB This work is an extension of our previous paper (Icarus 160 (2002) 73), where we analyzed seasonal cycle of condensation and sublimation of CO2 ice in the polygonal features. Such structures are visible in several images of the southern polar region, obtained by Mars Orbiter Camera on board the Mars Global Surveyor. In images taken during the end of the southern spring, when the surrounding surface is free of the seasonal frost, CO2 ice still appears to be present within the polygonal troughs. In the previous paper we described how the thickness of CO2 ice in the troughs evolves throughout the seasons. Here, we consider the influence of this cycle on the spatially averaged surface temperature, which can be determined from the orbital IR measurements. We model data from the Thermal Emission Spectrometer (TES) on Mars Global Surveyor to constrain the physical properties of the regolith in general and water ice content in particular. We have found that the spring evolution of the spatially averaged surface temperature of the polygonal regions occurs in several distinctive steps. After recession of the seasonal ice cap, temperature increases rapidly no longer being controlled by the condensation point of the surface CO2 ice. During this first phase it reaches a value of about 20 K lower than that expected for smooth surface. This effect is observed in TES data and is due to the fact that CO2 ice within the polygonal troughs is still present at this stage. The sublimation of CO2 ice within the troughs and the resultant increase of the surface temperature to the expected value of about 275 K takes another 20 sols. The exact time when and in which way this CO2 ice sublimes completely away depends on several parameters. Our simulations suggest that the most important parameter is the thermal conductivity of the regolith which in turn depends on the amount of the subsurface water ice. Thus, measurements of the surface temperature of regions covered with polygonal features can be used to deduce the content of water ice in the regolith. (C) 2003 Elsevier Ltd. All rights reserved. C1 Warsaw Univ, Inst Geophys, PL-02093 Warsaw, Poland. Max Planck Inst Aeron, D-37191 Katlenburg Lindau, Germany. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Kossacki, KJ (reprint author), Warsaw Univ, Inst Geophys, Pasteura 7, PL-02093 Warsaw, Poland. NR 14 TC 10 Z9 10 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 AUG-SEP PY 2003 VL 51 IS 9-10 BP 569 EP 580 DI 10.1016/S0032-0633(03)00070-9 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 709JA UT WOS:000184621000005 ER PT J AU Remy, J Biennier, L Salama, F AF Remy, J Biennier, L Salama, F TI Plasma structure in a pulsed discharge environment SO PLASMA SOURCES SCIENCE & TECHNOLOGY LA English DT Article ID SPECTROSCOPY; RADICALS; IONS AB A pulsed slit discharge nozzle (PDN) has been developed in our laboratory to generate molecular ions in an astrophysically relevant environment. The free cold molecular ions are formed through soft (Penning) ionization of the neutral precursor molecules seeded in a supersonic free jet and are probed with cavity ringdown spectroscopy. An attempt is made to characterize the nature and the structure of the plasma that is generated in these experiments to optimize the yield of formation of ions in the jet. The experimental conditions are characterized by a strong pressure gradient in a short discharge zone. We find that the plasma generated in the PDN source is best characterized as an intense abnormal glow discharge and that its structure is reduced to a negative glow and to dark zones near the electrodes. We have calculated the parameters (length, thickness and cathode voltage fall) that are associated with the Crookes dark space and the negative glow in the plasma. We have also estimated the electron temperature (T-e) and density (n(e)) in the plasma. All these parameters are required to optimize the yield of formation of ions and radicals in the jet expansions, a key requirement in our experiments. C1 NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA. Eindhoven Univ Technol, Dept Appl Phys, NL-5600 MB Eindhoven, Netherlands. RP Remy, J (reprint author), NASA, Ames Res Ctr, Div Space Sci, MS 245-6, Moffett Field, CA 94035 USA. RI Salama, Farid/A-8787-2009; Biennier, Ludovic/O-1618-2014 OI Salama, Farid/0000-0002-6064-4401; NR 19 TC 15 Z9 15 U1 1 U2 6 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0963-0252 J9 PLASMA SOURCES SCI T JI Plasma Sources Sci. Technol. PD AUG PY 2003 VL 12 IS 3 BP 295 EP 301 AR PII S0963-0252(03)62133-X DI 10.1088/0963-0252/12/3/301 PG 7 WC Physics, Fluids & Plasmas SC Physics GA 720XX UT WOS:000185288900001 ER PT J AU Mack, WJ Islam, T Lee, Z Selzer, RH Hodis, HN AF Mack, WJ Islam, T Lee, Z Selzer, RH Hodis, HN TI Environmental tobacco smoke and carotid arterial stiffness SO PREVENTIVE MEDICINE LA English DT Article DE smoking; environmental tobacco smoke; atherosclerosis; arterial stiffness ID NUTRITION EXAMINATION SURVEY; CORONARY HEART-DISEASE; INTIMA-MEDIA THICKNESS; STAGE RENAL-DISEASE/; HEALTHY-YOUNG ADULTS; PASSIVE SMOKING; CIGARETTE-SMOKING; CARDIOVASCULAR MORTALITY; PULSE PRESSURE; AORTIC STIFFNESS AB Background. Although active smoking acutely increases arterial stiffness, the association between arterial stiffness and chronic exposure to environmental tobacco smoke (ETS) has not been evaluated. We used baseline data from the Vitamin E Atherosclerosis Prevention Study to evaluate the association between ETS exposure and arterial stiffness among 227 healthy adult nonsmokers. Methods. B-mode ultrasonograms of the common carotid artery were used to compute the carotid arterial wall stiffness index beta. Beta was compared by the number of sources and daily hours of ETS exposure. Results. The carotid stiffness index beta was positively associated with age, body mass index (BMI), fasting glucose, and common carotid artery intima-media thickness (IMT). In the total sample, beta was not related to the number of ETS exposure sources. The carotid stiffness index beta increased with number of sources and daily hours of ETS in subjects with BMI greater than or equal to 27.1 kg/m(2) and IMT greater than or equal to 0.707 mm. The association was not apparent in subjects with lower BMI or IMT (for number of ETS sources, interaction P values 0.006 and 0.01, respectively). For number of ETS sources, but not hours of exposure, positive associations were apparent among females (but not males) and among subjects greater than or equal to55 years old (but not younger subjects). Conclusions. These data indicate that arterial stiffness is adversely associated with ETS in a dose-dependent manner among individuals with higher BMI and greater carotid artery IMT. (C) 2003 American Health Foundation and Elsevier Science (USA). All rights reserved. C1 Univ So Calif, Keck Sch Med, Dept Prevent Med, Los Angeles, CA 90033 USA. Univ So Calif, Keck Sch Med, Dept Med, Los Angeles, CA 90033 USA. Univ So Calif, Atherosclerosis Res Unit, Los Angeles, CA USA. CALTECH, Jet Prop Lab, Pasadena, CA USA. RP Mack, WJ (reprint author), Univ So Calif, Keck Sch Med, Dept Prevent Med, 1540 Alcazar St,CHP-218, Los Angeles, CA 90033 USA. FU NIA NIH HHS [AG-13860] NR 37 TC 31 Z9 34 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 0091-7435 J9 PREV MED JI Prev. Med. PD AUG PY 2003 VL 37 IS 2 BP 148 EP 154 DI 10.1016/S0091-7435(03)00097-5 PG 7 WC Public, Environmental & Occupational Health; Medicine, General & Internal SC Public, Environmental & Occupational Health; General & Internal Medicine GA 703UJ UT WOS:000184299200009 PM 12855214 ER PT J AU Lonsdale, CJ Smith, HE Rowan-Robinson, M Surace, J Shupe, D Xu, C Oliver, S Padgett, D Fang, F Conrow, T Franceschini, A Gautier, N Griffin, M Hacking, P Masci, F Morrison, G O'Linger, J Owen, F Perez-Fournon, I Pierre, M Puetter, R Stacey, G Castro, S Polletta, MD Farrah, D Jarrett, T Frayer, D Siana, B Babbedge, T Dye, S Fox, M Gonzalez-Solares, E Salaman, M Berta, S Condon, JJ Dole, H Serjeant, S AF Lonsdale, CJ Smith, HE Rowan-Robinson, M Surace, J Shupe, D Xu, C Oliver, S Padgett, D Fang, F Conrow, T Franceschini, A Gautier, N Griffin, M Hacking, P Masci, F Morrison, G O'Linger, J Owen, F Perez-Fournon, I Pierre, M Puetter, R Stacey, G Castro, S Polletta, MD Farrah, D Jarrett, T Frayer, D Siana, B Babbedge, T Dye, S Fox, M Gonzalez-Solares, E Salaman, M Berta, S Condon, JJ Dole, H Serjeant, S TI SWIRE: The SIRTF wide-area infrared extragalactic survey SO PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF THE PACIFIC LA English DT Review ID SPECTRAL ENERGY-DISTRIBUTIONS; HUBBLE DEEP FIELD; GALAXY REDSHIFT SURVEY; LARGE-SCALE STRUCTURE; DIGITAL SKY SURVEY; X-RAY SURVEY; STAR-FORMATION HISTORY; BRIGHT QUASAR SURVEY; RADIO-QUIET QUASARS; PHOTOMETRIC REDSHIFTS AB The SIRTF Wide-Area Infrared Extragalactic Survey (SWIRE), the largest SIRTF Legacy program, is a wide-area imaging survey to trace the evolution of dusty, star-forming galaxies, evolved stellar populations, and active galactic nuclei (AGNs) as a function of environment, from redshifts to the current z similar to 3 epoch. SWIRE will survey seven high-latitude fields, totaling 60 - 65 deg(2) in all seven SIRTF bands: Infrared Array Camera (IRAC) 3.6, 4.5, 5.6, and 8 mum and Multiband Imaging Photometer for SIRTF (MIPS) 24, 70, and 160 mum. Extensive modeling suggests that the Legacy Extragalactic Catalog may contain in excess of 2 million IR-selected galaxies, dominated by (1) similar to 150,000 luminous infrared galaxies (LIRGs; L-FIR > 10(11) L-.) detected by MIPS (and significantly more detected by IRAC), similar to 7000 of these with z > 2; (2) 1 million IRAC-detected early-type galaxies (similar to2 x 10(5) with z > 1 and similar to 10,000 with z > 2); and (3) similar to 20,000 classical AGNs detected with MIPS, plus significantly more dust-obscured quasi-stellar objects/AGNs among the LIRGs. SWIRE will provide an unprecedented view of the evolution of galaxies, structure, and AGNs. The key scientific goals of SWIRE are ( 1) to determine the evolution of actively star forming and passively evolving galaxies in order to understand the history of galaxy formation in the context of cosmic structure formation; ( 2) to determine the evolution of the spatial distribution and clustering of evolved galaxies, starbursts, and AGNs in the key redshift range 0.5 < z < 3 over which much of cosmic evolution has occurred; and (3) to determine the evolutionary relationship between "normal galaxies" and AGNs and the contribution of AGN accretion energy versus stellar nucleosynthesis to the cosmic backgrounds. The large area of SWIRE is important to establish statistically significant population samples over enough volume cells that we can resolve the star formation history as a function of epoch and environment, i.e., in the context of structure formation. The large volume is also optimized for finding rare objects. The SWIRE fields are likely to become the next generation of large "cosmic windows" into the extragalactic sky. They have been uniquely selected to minimize Galactic cirrus emission over large scales. The Galaxy Evolution Explorer will observe them as part of its deep 100 deg(2) survey, as will Herschel. SWIRE includes similar to 9 deg(2) of the unique large-area XMM Large Scale Structure hard X-ray imaging survey and is partly covered by the UKIDSS deep J and K survey. An extensive optical/near-IR imaging program is underway from the ground. The SWIRE data are nonproprietary; catalogs and images will be released twice yearly, beginning about 11 months after SIRTF launch. Details of the data products and release schedule are presented. C1 CALTECH, Ctr Infrared Proc & Anal, Pasadena, CA 91125 USA. Univ Calif San Diego, Ctr Astrophys & Space Sci, La Jolla, CA 92093 USA. Univ Calif San Diego, Dept Phys, San Diego, CA 92103 USA. Univ London Imperial Coll Sci Technol & Med, Blackett Lab, Astrophys Grp, London SW7 2BW, England. Univ Sussex, Ctr Astron, CPES, Brighton BN1 9QJ, E Sussex, England. Univ Padua, Dipartimento Astron, Vicolo Osservatorio, I-35122 Padua, Italy. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Cardiff Univ, Dept Phys & Astron, Cardiff CF24 3YB, S Glam, Wales. El Camino Coll, Dept Astron, Torrance, CA 90506 USA. Natl Radio Astron Observ, Socorro, NM 87801 USA. Inst Astrofis Canarias, Tenerife 38200, Spain. CEA, DSM, DAPNIA, Serv Astrophys, F-91191 Gif Sur Yvette, France. Pixon LLC, San Diego, CA 92123 USA. Cornell Univ, Dept Astron, Ithaca, NY 14853 USA. Natl Radio Astron Observ, Charlottesville, VA 22903 USA. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. Univ Kent, Sch Phys Sci, Ctr Astron & Planetary Sci, Canterbury CT2 7NZ, Kent, England. RP CALTECH, Ctr Infrared Proc & Anal, 100-22, Pasadena, CA 91125 USA. EM cjl@ipac.caltech.edu; hsmith@ucsd.edu RI Oliver, Seb/A-2479-2013; OI Oliver, Seb/0000-0001-7862-1032; Dye, Simon/0000-0002-1318-8343 NR 166 TC 493 Z9 493 U1 0 U2 5 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-6280 EI 1538-3873 J9 PUBL ASTRON SOC PAC JI Publ. Astron. Soc. Pac. PD AUG PY 2003 VL 115 IS 810 BP 897 EP 927 DI 10.1086/376850 PG 31 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 704DK UT WOS:000184322400001 ER PT J AU Kennicutt, RC Armus, L Bendo, G Calzetti, D Dale, DA Draine, BT Engelbracht, CW Gordon, KD Grauer, AD Helou, G Hollenbach, DJ Jarrett, TH Kewley, LJ Leitherer, C Li, A Malhotra, S Regan, MW Rieke, GH Rieke, MJ Roussel, H Smith, JDT Thornley, MD Walter, F AF Kennicutt, RC Armus, L Bendo, G Calzetti, D Dale, DA Draine, BT Engelbracht, CW Gordon, KD Grauer, AD Helou, G Hollenbach, DJ Jarrett, TH Kewley, LJ Leitherer, C Li, A Malhotra, S Regan, MW Rieke, GH Rieke, MJ Roussel, H Smith, JDT Thornley, MD Walter, F TI SINGS: The SIRTF nearby galaxies survey SO PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF THE PACIFIC LA English DT Review ID STAR-FORMING GALAXIES; SPECTRAL ENERGY-DISTRIBUTION; SPACE-OBSERVATORY ATLAS; VIRGO CLUSTER GALAXIES; BRIGHT SPIRAL GALAXIES; SHORT-WAVELENGTH SPECTROMETER; FABRY-PEROT OBSERVATIONS; CLERK-MAXWELL-TELESCOPE; WESTERBORK HI SURVEY; INTERSTELLAR-MEDIUM AB The SIRTF Nearby Galaxy Survey is a comprehensive infrared imaging and spectroscopic survey of 75 nearby galaxies. Its primary goal is to characterize the infrared emission of galaxies and their principal infrared-emitting components, across a broad range of galaxy properties and star formation environments. SINGS will provide new insights into the physical processes connecting star formation to the interstellar medium properties of galaxies and provide a vital foundation for understanding infrared observations of the distant universe and ultraluminous and active galaxies. The galaxy sample and observing strategy have been designed to maximize the scientific and archival value of the data set for the SIRTF user community at large. The SIRTF images and spectra will be supplemented by a comprehensive multiwavelength library of ancillary and complementary observations, including radio continuum, H I, CO, submillimeter, BVRIJHK, Halpha, Paalpha, ultraviolet, and X-ray data. This paper describes the main astrophysical issues to be addressed by SINGS, the galaxy sample and the observing strategy, and the SIRTF and other ancillary data products. C1 Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. CALTECH, SIRTF Sci Ctr, Pasadena, CA 91125 USA. Space Telescope Sci Inst, Baltimore, MD 21218 USA. Univ Wyoming, Dept Phys & Astron, Laramie, WY 82071 USA. Princeton Univ, Dept Astrophys Sci, Princeton, NJ 08544 USA. CALTECH, Pasadena, CA 91101 USA. Univ Arkansas, Dept Phys & Astron, Little Rock, AR 72204 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Bucknell Univ, Dept Phys, Lewisburg, PA 17837 USA. Natl Radio Astron Observ, Socorro, NM 87801 USA. RP Kennicutt, RC (reprint author), Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. OI Draine, Bruce/0000-0002-0846-936X NR 106 TC 776 Z9 779 U1 1 U2 5 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-6280 EI 1538-3873 J9 PUBL ASTRON SOC PAC JI Publ. Astron. Soc. Pac. PD AUG PY 2003 VL 115 IS 810 BP 928 EP 952 PG 25 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 704DK UT WOS:000184322400002 ER PT J AU Evans, NJ Allen, LE Blake, GA Boogert, ACA Bourke, T Harvey, PM Kessler, JE Koerner, DW Lee, CW Mundy, LG Myers, PC Padgett, DL Pontoppidan, K Sargent, AI Stapelfeldt, KR van Dishoeck, EF Young, CH Young, KE AF Evans, NJ Allen, LE Blake, GA Boogert, ACA Bourke, T Harvey, PM Kessler, JE Koerner, DW Lee, CW Mundy, LG Myers, PC Padgett, DL Pontoppidan, K Sargent, AI Stapelfeldt, KR van Dishoeck, EF Young, CH Young, KE TI From molecular cores to planet-forming disks: An SIRTF legacy program SO PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF THE PACIFIC LA English DT Article ID TELESCOPE-FACILITY SIRTF; INTERMEDIATE-MASS STARS; MAIN-SEQUENCE STARS; CIRCUMSTELLAR DISKS; ISO SPECTROSCOPY; BROWN DWARFS; SPECTRAL ENERGY; TAURUS-AURIGA; DENSE CORES; DARK CLOUD AB Crucial steps in the formation of stars and planets can be studied only at mid- to far-infrared wavelengths, where the Space Infrared Telescope (SIRTF) provides an unprecedented improvement in sensitivity. We will use all three SIRTF instruments ( Infrared Array Camera [IRAC], Multiband Imaging Photometer for SIRTF [MIPS], and Infrared Spectrograph [IRS]) to observe sources that span the evolutionary sequence from molecular cores to protoplanetary disks, encompassing a wide range of cloud masses, stellar masses, and star-forming environments. In addition to targeting about 150 known compact cores, we will survey with IRAC and MIPS (3.6 - 70 mum) the entire areas of five of the nearest large molecular clouds for new candidate protostars and substellar objects as faint as 0.001 solar luminosities. We will also observe with IRAC and MIPS about 190 systems likely to be in the early stages of planetary system formation ( ages up to about 10 Myr), probing the evolution of the circumstellar dust, the raw material for planetary cores. Candidate planet-forming disks as small as 0.1 lunar masses will be detectable. Spectroscopy with IRS of new objects found in the surveys and of a select group of known objects will add vital information on the changing chemical and physical conditions in the disks and envelopes. The resulting data products will include catalogs of thousands of previously unknown sources, multiwavelength maps of about 20 deg(2) of molecular clouds, photometry of about 190 known young stars, spectra of at least 170 sources, ancillary data from ground-based telescopes, and new tools for analysis and modeling. These products will constitute the foundations for many follow-up studies with ground-based telescopes, as well as with SIRTF itself and other space missions such as SIM, JWST, Herschel, and TPF/ Darwin. C1 Univ Texas, Dept Astron, Austin, TX 78712 USA. Smithsonian Astrophys Observ, Cambridge, MA 02138 USA. CALTECH, Div Geol & Planetary Sci, Pasadena, CA 91125 USA. CALTECH, Div Phys Math & Astron, Pasadena, CA 91125 USA. CALTECH, Div Chem & Chem Engn, Pasadena, CA 91125 USA. No Arizona Univ, Dept Phys & Astron, Flagstaff, AZ 86011 USA. Korea Astron Observ, Taeduk Radio Astron Observ, Taejon 305348, South Korea. Univ Maryland, Dept Astron, College Pk, MD 20742 USA. SIRTF Sci Ctr, Pasadena, CA 91125 USA. Leiden Observ, NL-2300 RA Leiden, Netherlands. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Evans, NJ (reprint author), Univ Texas, Dept Astron, 1 Univ Stn C1400, Austin, TX 78712 USA. RI Stapelfeldt, Karl/D-2721-2012 NR 58 TC 354 Z9 355 U1 0 U2 4 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 AUG PY 2003 VL 115 IS 810 BP 965 EP 980 DI 10.1086/376697 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 704DK UT WOS:000184322400004 ER PT J AU Bauer, JM Fernandez, YR Meech, KJ AF Bauer, JM Fernandez, YR Meech, KJ TI An optical survey of the active centaur C/NEAT (2001 T4) SO PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF THE PACIFIC LA English DT Article ID KUIPER-BELT OBJECTS; OUTER SOLAR-SYSTEM; COSMIC-RAY PARTICLES; O1 HALE-BOPP; ORBITAL EVOLUTION; INTERSTELLAR ICES; CHIRON; COMETS; DUST; DIVERSITY AB We present the results of optical observations of C/NEAT ( 2001 T4) taken on three dates between 2001 October and 2002 September at the University of Hawaii 2.2 m telescope. Coma was present for each observation, but the activity level was variable. We present surface brightness profiles, dust production rates, and evidence for structure in the coma. There is a radial gradient in coma color, with the outer coma exhibiting the least red colors. The object's V - R and R - I colors indicate that this is one of the reddest objects with a Centaur-type orbit. C1 Univ Hawaii, Inst Astron, Honolulu, HI 96822 USA. RP Bauer, JM (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 183-501, Pasadena, CA 91109 USA. EM bauer@scn.jpl.nasa.gov OI Fernandez, Yanga/0000-0003-1156-9721 NR 53 TC 24 Z9 24 U1 0 U2 0 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 AUG PY 2003 VL 115 IS 810 BP 981 EP 989 DI 10.1086/377012 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 704DK UT WOS:000184322400005 ER PT J AU McKeever, SWS Banerjee, D Blair, M Clifford, SM Clowdsley, MS Kim, SS Lamothe, M Lepper, K Leuschen, M McKeever, KJ Prather, M Rowland, A Reust, D Sears, DWG Wilson, JW AF McKeever, SWS Banerjee, D Blair, M Clifford, SM Clowdsley, MS Kim, SS Lamothe, M Lepper, K Leuschen, M McKeever, KJ Prather, M Rowland, A Reust, D Sears, DWG Wilson, JW TI Concepts and approaches to in situ luminescence dating of martian sediments SO RADIATION MEASUREMENTS LA English DT Article; Proceedings Paper CT 10th International Conference on Luminescence and Electron Spin Resonance Dating (LED 2002) CY JUN 24-28, 2002 CL RENO, NEVADA ID POLAR LAYERED DEPOSITS; POLYMINERAL FINE GRAINS; JSC MARS-1; SURFACE; REGION; EARTH; SOIL; PATHFINDER; FELDSPARS; SPACE AB In this paper we present the concept of a robotic instrument for in situ luminescence dating of near-surface sediments on Mars. The scientific objectives and advantages to be gained from the development of such an instrument are described, and the challenges presented by the Mars surface environment to the design and operation of the instrument are outlined. (C) 2003 Published by Elsevier Ltd. C1 Oklahoma State Univ, Arkansas Oklahoma Ctr Space & Planetary Sci, Stillwater, OK 74078 USA. Oklahoma State Univ, Dept Phys, Stillwater, OK 74078 USA. Lunar & Planetary Inst, Houston, TX 77058 USA. NASA, Langley Res Ctr, NRC, Hampton, VA 23681 USA. Jet Prop Lab, Pasadena, CA 91109 USA. Univ Quebec, Dept Sci Terre & Atmosphere, Montreal, PQ H3C 3P8, Canada. Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Nomad Inc, Stillwater, OK 74076 USA. Univ Arkansas, Arkansas Oklahoma Ctr Space & Planetary Sci, Fayetteville, AR 72701 USA. Univ Arkansas, Dept Chem, Fayetteville, AR 72701 USA. RP McKeever, SWS (reprint author), Oklahoma State Univ, Arkansas Oklahoma Ctr Space & Planetary Sci, Stillwater, OK 74078 USA. NR 34 TC 26 Z9 26 U1 0 U2 4 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1350-4487 J9 RADIAT MEAS JI Radiat. Meas. PD AUG-OCT PY 2003 VL 37 IS 4-5 SI SI BP 527 EP 534 DI 10.1016/S1350-4487(03)00025-8 PG 8 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 700KD UT WOS:000184110400035 PM 12856693 ER PT J AU Zhuang, HQ Motaghedi, SH Roth, ZS Bai, Y AF Zhuang, HQ Motaghedi, SH Roth, ZS Bai, Y TI Calibration of multi-beam laser tracking systems SO ROBOTICS AND COMPUTER-INTEGRATED MANUFACTURING LA English DT Article ID DYNAMIC ROBOT MEASUREMENTS AB Laser tracking systems (LTSs) employ tracking laser interferometers for coordinate measuring of precision machine tools and robots. Such coordinate measuring machines, if properly calibrated, are potentially fast, very accurate and can cover a large workspace. LTS devices must be self-calibrated, using redundancy or constraint surfaces. A methodology for self-calibration of a multi-beam LTS utilizing planar constraints is formulated and demonstrated. A kinematic model of a multi-beam LTS is derived. Model error analysis demonstrates that the use of angular measurement of the gimbal joint positions, relatively inaccurate as these are, does improve the overall system calibration accuracy. Self-calibration model parameters observability of the multi-beam LTS is studied. The results reveal the applicability of planar constraints to system self-calibration. Simulation and experimentation results obtained on a prototype system are reported demonstrating the applicability of the calibration strategies. (C) 2003 Published by Elsevier Science Ltd. C1 Florida Atlantic Univ, Dept Elect Engn, Boca Raton, FL 33431 USA. Jet Prop Lab, Pasadena, CA 91109 USA. Johnson C Smith Lab, Dept Comp Sci & Engn, Charlotte, NC 28216 USA. RP Zhuang, HQ (reprint author), Florida Atlantic Univ, Dept Elect Engn, Boca Raton, FL 33431 USA. NR 18 TC 22 Z9 25 U1 3 U2 7 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0736-5845 J9 ROBOT CIM-INT MANUF JI Robot. Comput.-Integr. Manuf. PD AUG PY 2003 VL 19 IS 4 BP 301 EP 314 DI 10.1016/S0736-5845(02)00076-5 PG 14 WC Computer Science, Interdisciplinary Applications; Engineering, Manufacturing; Robotics SC Computer Science; Engineering; Robotics GA 695YW UT WOS:000183858800001 ER PT J AU Zhou, XH Gaines, DM AF Zhou, XH Gaines, DM TI ARM: A tool for identifying and repairing un-machinable shapes in designs SO ROBOTICS AND COMPUTER-INTEGRATED MANUFACTURING LA English DT Article ID REDESIGN SUGGESTIONS; FEATURE RECOGNIZER; FEATURES AB Providing early feedback on the manufacturability of a part design can greatly improve the quality of the product while reducing the time and cost of production. However, the necessary manufacturing knowledge is not always available. Computer tools that can provide this manufacturing knowledge by analyzing a design suggesting changes to improve its manufacturability would be a valuable asset to a designer. To this end, we present an approach to automatically generate redesign suggestions to improve the manufacturability of machined parts. Novel aspects of this approach include the ability to identify un-machinable shapes in a part and transform them into machinable features and to automatically identify the possible shape transformations based on properties of the machining equipment. This increases the scope of redesign generation tools by allowing them to be applied to parts that are not already machinable. We have developed a system called automated redesign for machined parts (ARM) that assists users in repairing parts that contain un-machinable shapes. (C) 2003 Elsevier Science Ltd. All rights reserved. C1 Jet Prop Lab, Artificial Intelligence Grp, Pasadena, CA 91109 USA. Vanderbilt Univ, Dept Elect Engn & Comp Sci, Nashville, TN USA. RP Gaines, DM (reprint author), Jet Prop Lab, Artificial Intelligence Grp, 4800 Oak Dr MS 126-347, Pasadena, CA 91109 USA. NR 23 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 0736-5845 J9 ROBOT CIM-INT MANUF JI Robot. Comput.-Integr. Manuf. PD AUG PY 2003 VL 19 IS 4 BP 343 EP 353 DI 10.1016/S0736-5845(03)00023-1 PG 11 WC Computer Science, Interdisciplinary Applications; Engineering, Manufacturing; Robotics SC Computer Science; Engineering; Robotics GA 695YW UT WOS:000183858800004 ER PT J AU Young, RC Buttner, WJ Linnell, BR Ramesham, R AF Young, RC Buttner, WJ Linnell, BR Ramesham, R TI Electronic nose for space program applications SO SENSORS AND ACTUATORS B-CHEMICAL LA English DT Article; Proceedings Paper CT 9th International Meeting on Chemical Sensors (IMCS-9) CY JUL 07-10, 2002 CL BOSTON, MASSACHUSETTS DE electronic nose; air quality monitor; fire detection; space program; hypergolic fuel; pattern recognition; classification ID FEATURE-SELECTION AB The ability to monitor air contaminants in the shuttle and the International Space Station is important to ensure the health and safety of astronauts, and equipment integrity. Three specific space applications have been identified that would benefit from a chemical monitor: (a) organic contaminants in space cabin air; (b) hypergolic propellant contaminants in the shuttle airlock; (c) pre-combustion signature vapors from electrical fires. NASA at Kennedy Space Center (KSC) is assessing several commercial and developing electronic noses (E-noses) for these applications. A short series of tests identified those E-noses that exhibited sufficient sensitivity to the vapors of interest. Only two E-noses exhibited sufficient sensitivity for hypergolic fuels at the required levels, while several commercial E-noses showed sufficient sensitivity of common organic vapors. These E-noses were subjected to further tests to assess their ability to identify vapors. Development and testing of E-nose models using vendor supplied software packages correctly identified vapors with an accuracy of 70-90%. In-house software improvements increased the identification rates between 90 and 100%. Further software enhancements are under development. Details on the experimental setup, test protocols, and results on E-nose performance are presented in this paper along with special emphasis on specific software enhancements. (C) 2003 Elsevier Science B.V. All rights reserved. C1 NASA, Appl Chem Lab, Kennedy Space Ctr, FL 32899 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Young, RC (reprint author), NASA, Appl Chem Lab, Kennedy Space Ctr, FL 32899 USA. NR 15 TC 39 Z9 42 U1 1 U2 7 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0925-4005 J9 SENSOR ACTUAT B-CHEM JI Sens. Actuator B-Chem. PD AUG 1 PY 2003 VL 93 IS 1-3 BP 7 EP 16 DI 10.1016/S0925-4005(03)00338-1 PG 10 WC Chemistry, Analytical; Electrochemistry; Instruments & Instrumentation SC Chemistry; Electrochemistry; Instruments & Instrumentation GA 703DV UT WOS:000184265500002 PM 14584511 ER PT J AU Shevade, AV Ryan, MA Homer, ML Manfreda, AM Zhou, H Manatt, KS AF Shevade, AV Ryan, MA Homer, ML Manfreda, AM Zhou, H Manatt, KS TI Molecular modeling of polymer composite-analyte interactions in electronic nose sensors SO SENSORS AND ACTUATORS B-CHEMICAL LA English DT Article; Proceedings Paper CT 9th International Meeting on Chemical Sensors (IMCS-9) CY JUL 07-10, 2002 CL BOSTON, MASSACHUSETTS DE electronic nose; polymer composite; molecular modeling; interactions ID SIMULATIONS; TECHNOLOGY; ODOR AB We report a molecular modeling study to investigate the polymer-carbon black (CB) composite-analyte interactions in resistive sensors. These sensors comprise the JPL electronic nose (ENose) sensing array developed for monitoring breathing air in human habitats. The polymer in the composite is modeled based on its stereoisomerism and sequence isomerism, while the CB is modeled as uncharged naphthalene rings with no hydrogens. The Dreiding 2.21 force field is used for the polymer, solvent molecules and graphite parameters are assigned to the carbon black atoms. A combination of molecular mechanics (MM) and molecular dynamics (NPT-MD and NVT-MD) techniques are used to obtain the equilibrium composite structure by inserting naphthalene rings in the polymer matrix. Polymers considered for this work include poly(4-vinylphenol), polyethylene oxide, and ethyl cellulose. Analytes studied are representative of both inorganic and organic compounds. The results are analyzed for the composite microstructure by calculating the radial distribution profiles as well as for the sensor response by predicting the interaction energies of the analytes with the composites. (C) 2003 Elsevier Science B.V. All rights reserved. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Ryan, MA (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 22 TC 56 Z9 57 U1 1 U2 16 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0925-4005 J9 SENSOR ACTUAT B-CHEM JI Sens. Actuator B-Chem. PD AUG 1 PY 2003 VL 93 IS 1-3 BP 84 EP 91 DI 10.1016/S0925-4005(03)00245-4 PG 8 WC Chemistry, Analytical; Electrochemistry; Instruments & Instrumentation SC Chemistry; Electrochemistry; Instruments & Instrumentation GA 703DV UT WOS:000184265500012 PM 12974241 ER PT J AU Bewsher, D Parnell, CE Pike, CD Harrison, RA AF Bewsher, D Parnell, CE Pike, CD Harrison, RA TI Dynamics of blinkers SO SOLAR PHYSICS LA English DT Article ID SOLAR TRANSITION REGION; DOPPLER WAVELENGTH SHIFTS; QUIET-SUN; ACTIVE REGIONS; LINE-PROFILES; EMISSION-LINE; SUMER; VELOCITIES; SPECTRA; SOHO AB The relative Doppler and non-thermal velocities of quiet-Sun and active-region blinkers identified in O V with CDS are calculated. Relative velocities for the corresponding chromospheric plasma below are also determined using the He I line. O V blinkers and the chromosphere directly below, have a preference to be more red-shifted than the normal transition region and chromospheric plasma. The ranges of these enhanced velocities, however, are no larger than the typical spread of Doppler velocities in these regions. The anticipated ranges of Doppler velocities of blinkers are 10 - 15 km s(-1) in the quiet Sun (10 - 20 km s(-1) in active regions) for He I and 25 - 30 km s(-1) in the quiet Sun (20 - 40 km s(-1) in active regions) for O V. Blinkers and the chromosphere below also have preferentially larger non-thermal velocities than the typical background chromosphere and transition region. Again the increase in magnitude of these non-thermal velocities is no greater than the typical ranges of non-thermal velocities. The ranges of non-thermal velocities of blinkers in both the quiet Sun and active regions are estimated to be 15 - 25 km s(-1) in He I and 30 - 45 km s(-1) in O V. There are more blinkers with larger Doppler and non-thermal velocities than would be expected in the whole of the chromosphere and transition region. The recently suggested mechanisms for blinkers are revisited and discussed further in light of the new results. C1 Univ St Andrews, Math Inst, St Andrews KY16 9SS, Fife, Scotland. Rutherford Appleton Lab, Dept Space Sci, Didcot OX11 0QX, Oxon, England. RP Bewsher, D (reprint author), NASA, Goddard Space Flight Ctr, ESA, Dept Space Sci, Mailcode 682-3, Greenbelt, MD 20771 USA. OI Bewsher, Danielle/0000-0002-6351-5170 NR 26 TC 16 Z9 16 U1 0 U2 2 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-0938 J9 SOL PHYS JI Sol. Phys. PD AUG PY 2003 VL 215 IS 2 BP 217 EP 237 DI 10.1023/A:1025642612049 PG 21 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 719XF UT WOS:000185229800002 ER PT J AU Hui, D Kim, JS Kim, YT An, I Paley, MS AF Hui, D Kim, JS Kim, YT An, I Paley, MS TI Monitoring photodeposition of polymer films from diacetylene monomer solutions using in situ real-time spectroscopic ellipsometry SO THIN SOLID FILMS LA English DT Article DE photodeposition; diacetylene monomer; real-time spectroscopic ellipsometry ID LANGMUIR-BLODGETT-FILMS; OPTICAL-PROPERTIES; THIN-FILMS; GROWTH; DEPOSITION; BEHAVIOR; SILICON; GOLD AB Photodeposition of thin polymer (PDAMNA) films from diacetylene monomer (DAMNA) solutions onto 80 Angstrom gold coated silica substrates with UV light was studied using the technique of in situ real-time spectroscopic ellipsometry. The dielectric function of the PDAMNA film was determined, and it reveals typical optical properties for organic materials in the photon energy range (1.6-2.7 eV). The thickness of a growing PDAMNA film over a 4-h time interval was determined using a linear regression fit of the experimental data to a homogeneous four phase optical model. The growth rate was observed to be essentially linear with time during the early stages of photodeposition, as expected. However, it was found that stirring the solution dramatically lowered the rate of film deposition. It is believed that fluid flow enhances transport of reactive species generated in the vicinity of the substrate away from the surface and into the bulk solution, where they become quenched. Lastly, the morphology of the PDAMNA film was examined using non-contact mode atomic force microscopy, indicating that the film contains embedded aggregates of precipitated polymer with diameters ranging from 20 to 100 nm. These results are consistent with those obtained previously using optical microscopy. (C) 2003 Elsevier Science B.V. All rights reserved. C1 NASA, George C Marshall Space Flight Ctr, Space Sci Lab SD48, Huntsville, AL 35812 USA. Yonsei Univ, Ctr Artificial Lipid Membranes, Seoul, South Korea. Yonsei Univ, Dept Chem, Seoul, South Korea. Hanyang Univ, Res Ctr Elect Mat & Components, Ansan, South Korea. Hanyang Univ, Dept Phys, Ansan, South Korea. RP Paley, MS (reprint author), NASA, George C Marshall Space Flight Ctr, Space Sci Lab SD48, Huntsville, AL 35812 USA. RI Wu, Qihong/B-9803-2009 NR 26 TC 4 Z9 4 U1 1 U2 1 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 AUG 1 PY 2003 VL 437 IS 1-2 BP 127 EP 134 DI 10.1016/S0040-6090(03)00677-1 PG 8 WC Materials Science, Multidisciplinary; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Materials Science; Physics GA 704XU UT WOS:000184367600019 ER PT J AU Hedges, SB Shah, P AF Hedges, SB Shah, P TI Comparison of mode estimation methods and application in molecular clock analysis SO BMC BIOINFORMATICS LA English DT Article ID PLANTS; FUNGI AB Background: Distributions of time estimates in molecular clock studies are sometimes skewed or contain outliers. In those cases, the mode is a better estimator of the overall time of divergence than the mean or median. However, different methods are available for estimating the mode. We compared these methods in simulations to determine their strengths and weaknesses and further assessed their performance when applied to real data sets from a molecular clock study. Results: We found that the half-range mode and robust parametric mode methods have a lower bias than other mode methods under a diversity of conditions. However, the half-range mode suffers from a relatively high variance and the robust parametric mode is more susceptible to bias by outliers. We determined that bootstrapping reduces the variance of both mode estimators. Application of the different methods to real data sets yielded results that were concordant with the simulations. Conclusion: Because the half-range mode is a simple and fast method, and produced less bias overall in our simulations, we recommend the bootstrapped version of it as a general-purpose mode estimator and suggest a bootstrap method for obtaining the standard error and 95% confidence interval of the mode. C1 Penn State Univ, NASA, Mueller Lab 208, Astrobiol Inst, University Pk, PA 16802 USA. Penn State Univ, Dept Biol, Mueller Lab 208, University Pk, PA 16802 USA. RP Hedges, SB (reprint author), Penn State Univ, NASA, Mueller Lab 208, Astrobiol Inst, University Pk, PA 16802 USA. NR 18 TC 28 Z9 28 U1 0 U2 1 PU BIOMED CENTRAL LTD PI LONDON PA MIDDLESEX HOUSE, 34-42 CLEVELAND ST, LONDON W1T 4LB, ENGLAND SN 1471-2105 J9 BMC BIOINFORMATICS JI BMC Bioinformatics PD JUL 31 PY 2003 VL 4 AR 31 DI 10.1186/1471-2105-4-31 PG 11 WC Biochemical Research Methods; Biotechnology & Applied Microbiology; Mathematical & Computational Biology SC Biochemistry & Molecular Biology; Biotechnology & Applied Microbiology; Mathematical & Computational Biology GA 711GA UT WOS:000184730200001 PM 12892571 ER PT J AU Cinke, M Li, J Bauschlicher, CW Ricca, A Meyyappan, M AF Cinke, M Li, J Bauschlicher, CW Ricca, A Meyyappan, M TI CO2 adsorption in single-walled carbon nanotubes SO CHEMICAL PHYSICS LETTERS LA English DT Article ID BASIS-SETS AB Adsorption of CO2 on purified single-walled carbon nanotubes (SWNTs) has been studied in the temperature range of 0-200 degreesC and found to be mainly a physisorption process. The SWNTs adsorb nearly twice the volume of CO, compared to activated carbon. The experimental results yield a CO, heat of adsorption of 2303 J/mol (0.024 eV) in SWNTs. Our computational study yields a similar binding energy and shows that the CO2 is physisorbed side-on to the nanotube. (C) 2003 Elsevier B.V. All rights reserved. C1 NASA, Ames Res Ctr, Ctr Nanotechnol, Moffett Field, CA 94035 USA. RP Li, J (reprint author), NASA, Ames Res Ctr, Ctr Nanotechnol, MS 229-1, Moffett Field, CA 94035 USA. NR 17 TC 183 Z9 184 U1 3 U2 51 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 JUL 31 PY 2003 VL 376 IS 5-6 BP 761 EP 766 DI 10.1016/S0009-2614(03)01124-2 PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 708KL UT WOS:000184565900034 ER PT J AU Wang, J Christopher, SA Reid, JS Maring, H Savoie, D Holben, BN Livingston, JM Russell, PB Yang, SK AF Wang, J Christopher, SA Reid, JS Maring, H Savoie, D Holben, BN Livingston, JM Russell, PB Yang, SK TI GOES 8 retrieval of dust aerosol optical thickness over the Atlantic Ocean during PRIDE SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE dust aerosol; diurnal optical depth; GOES 8; radiative forcing ID SUN PHOTOMETER MEASUREMENTS; BIOMASS BURNING AEROSOLS; SAHARAN DUST; MINERAL DUST; TROPOSPHERIC AEROSOLS; RADIATIVE CHARACTERISTICS; SOLAR WAVELENGTHS; SOUTH-AMERICA; UNITED-STATES; AVHRR DATA AB Using 30 days of half-hourly, high temporal resolution GOES 8 imager data and radiative transfer calculations, dust aerosol optical thickness (AOT) was retrieved over the Atlantic Ocean (14degreesN similar to 26degreesN, 73degreesW-63degreesW) during the Puerto Rico Dust Experiment ( PRIDE). Dust aerosol size distributions and complex index of refraction inferred from ground-based measurements (1.53-0.0015i at 0.55 mum), which were used in Mie calculations and a plane-parallel discrete ordinate radiative transfer model (DISORT) to compute look up tables for AOT retrievals. Using a combination of spectral, spatial, and temporal tests, a dust detection algorithm was developed from the GOES 8 imager data. The degradation of the signal response relative to the prelaunched calibration of the GOES 8 visible channel was 39% in July 2000 and the GOES 8 AOT detection limit was estimated to be 0.04 in AOT (0.67 mum). The satellite-retrieved AOT were then compared with AOT values derived from ground-based Sun photometer (SP) sites. The comparison showed that GOES 8 retrieved AOT are in good agreement with the SP derived values, with linear correlation coefficient of 0.91 and 0.80 for the two sites. The GOES 8 monthly mean 0.67 mm AOT (0.19 +/- 0.13, 0.22 +/- 0.12) over the two SP sites matched the monthly mean SPAOT values (0.23 +/- 0.13, 0.22 +/- 0.10). The linear correlation between the GOES 8 retrieved AOT and the aircraft derived values from particle probe data and airborne Sun photometer AATS-6 measurements were 0.88 and 0.83, respectively. Besides the uncertainties from the nonspherical effect of dust aerosols, sensitivity studies showed that the uncertainties (Deltatau) of the GOES 8 retrieved AOT values were mainly from the uncertainties due to the imaginary part of refractive index (Deltatau = +/-0.05) and surface reflectance [Deltatau = +/-(0.02 similar to 0.04)]. This paper demonstrates the application of geostationary satellites to detect and retrieve dust AOT even at low to moderate AOTs. The GOES 8 imager with high temporal resolutions also captures aerosol diurnal variation in this study that can further reduce the uncertainties in the current aerosol forcing estimations caused by the high temporal variations of AOT, thereby playing a complementary role with global AOT retrievals from polar orbiting satellites. C1 Univ Alabama, Dept Atmospher Sci, NSSTC, Huntsville, AL 35806 USA. SPAWAR Syst Ctr, Atmospher Propagat Branch, San Diego, CA USA. Univ Miami, Rosenstiel Sch Marine & Atmospher Sci, Miami, FL 33149 USA. NASA, Goddard Space Flight Ctr, Biospher Sci Branch, Greenbelt, MD 20771 USA. SRI Int, Menlo Pk, CA 94025 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Natl Ctr Environm Predict, Climate Predict Ctr, Washington, DC 20233 USA. RP Wang, J (reprint author), Univ Alabama, Dept Atmospher Sci, NSSTC, 320 Sparkman Dr, Huntsville, AL 35806 USA. EM sundar@nsstc.uah.edu RI Christopher, Sundar/E-6781-2011; Reid, Jeffrey/B-7633-2014; Wang, Jun/A-2977-2008 OI Reid, Jeffrey/0000-0002-5147-7955; Wang, Jun/0000-0002-7334-0490 NR 83 TC 26 Z9 27 U1 2 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 JUL 31 PY 2003 VL 108 IS D19 AR 8595 DI 10.1029/2002JD002494 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 710WZ UT WOS:000184707000001 ER PT J AU Lotsch, A Friedl, MA Anderson, BT Tucker, CJ AF Lotsch, A Friedl, MA Anderson, BT Tucker, CJ TI Coupled vegetation-precipitation variability observed from satellite and climate records SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID SEA-SURFACE TEMPERATURE; SOUTH-AMERICA; RAINFALL; PATTERNS; AFRICA; ANOMALIES; INDEX; EAST AB [1] Variability in precipitation regimes at seasonal and longer time scales strongly influences ecosystem dynamics in arid and semi-arid regions. In this paper, we use time series of global precipitation and satellite normalized difference vegetation index (NDVI) data to analyze joint spatial and temporal variability between terrestrial ecosystems and precipitation regimes. Accumulated monthly rainfall anomalies are quantified using a standardized precipitation index (SPI), which provides a better measure of ecologically significant precipitation excess or deficit at growing season time scales relative to monthly precipitation data. Results from canonical correlation analysis reveal geographically extensive patterns of joint NDVI-SPI variability suggestive of strong climate-biosphere coupling. Further, leading modes of covariability are shown to be related to large-scale ocean-atmosphere circulation anomalies. These results illustrate the global extent and sensitivity of ecosystems susceptible to climate change-induced perturbations in precipitation regimes. C1 Boston Univ, Dept Geog, Boston, MA 02215 USA. Boston Univ, Ctr Remote Sensing, Boston, MA 02215 USA. NASA, Goddard Space Flight Ctr, Biospher Sci Branch, Greenbelt, MD 20771 USA. RP Lotsch, A (reprint author), Boston Univ, Dept Geog, Boston, MA 02215 USA. NR 29 TC 71 Z9 75 U1 2 U2 16 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 JUL 30 PY 2003 VL 30 IS 14 AR 1774 DI 10.1029/2003GL017506 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 710WN UT WOS:000184706000003 ER PT J AU Colaprete, A Haberle, RM Toon, OB AF Colaprete, A Haberle, RM Toon, OB TI Formation of convective carbon dioxide clouds near the south pole of Mars SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article DE Mars; carbon dioxide clouds; convection; MOLA ID THERMAL EMISSION SPECTROMETER; ORBITER LASER ALTIMETER; MARTIAN ATMOSPHERE; GLOBAL SURVEYOR; ICE CLOUDS; MODEL; DUST; SNOW; CO2; STORMS AB [1] Observations from the Mars Orbiter Laser Altimeter (MOLA) indicate a distinct difference in the nature of north and south polar clouds. The majority of north polar clouds are diffuse with relatively low optical extinction ( channel 4 clouds). In contrast, a significant number of south polar clouds provide very strong laser echoes suggesting optical extinction as high as 300 km(-1) ( channel 1 clouds). These high extinction clouds were almost exclusively observed in the polar night between 70degrees and 85 degreesS. We have previously shown that the low extinction clouds are composed of a small number of large carbon dioxide particles, which form in relatively gentle updrafts, or lee waves. A possible explanation for the high extinction clouds is that they are composed of more, but somewhat smaller, carbon dioxide particles forming in high-velocity convective updrafts. Numerical simulations using a microphysical cloud model show that the cloud extinction depends most strongly on the availability of ice nuclei ( IN), assumed to be dust, and the updraft velocity. Radiative cooling by the CO2 clouds can further destabilize the air column. Cloud extinction consistent with MOLA observations is produced for IN concentrations greater than 5 cm(-3) and updraft core velocities of similar to2 m s(-1). The discrepancy in north and south cloud extinction may be the result of differing IN concentrations and stability regimes between the north and south polar regions. Many channel 4 clouds may also be convective but formed in air with either low updraft velocities or low abundances of ice nuclei. C1 NASA, Div Space Sci, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ Colorado, Program Atmospher & Ocean Sci, Atmospher & Space Phys Lab, Boulder, CO 80309 USA. RP Colaprete, A (reprint author), NASA, Div Space Sci, Ames Res Ctr, MS 245-3, Moffett Field, CA 94035 USA. NR 37 TC 26 Z9 26 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 JUL 30 PY 2003 VL 108 IS E7 AR 5081 DI 10.1029/2003JE002053 PG 19 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 710XH UT WOS:000184707800003 ER PT J AU Crider, DH Vondrak, RR AF Crider, DH Vondrak, RR TI Space weathering effects on lunar cold trap deposits SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article DE Lunar polar ice; lunar cold traps; lunar space weathering; lunar regolith processes; lunar gardening simulation; lunar volatiles ID POLAR HYDROGEN DEPOSITS; SOLAR-WIND BOMBARDMENT; WATER ICE; CHEMICAL IMPLANTATION; POLES; MOON; SURFACE; ATMOSPHERE; REGIONS; INTERSTELLAR AB [1] Both steady and episodic sources have been proposed as sources of hydrogen observed by Lunar Prospector in association with the regions of permanent shadow at the poles of the Moon. Either source could supply significant quantities of water to the poles. However, space weathering processes affect the retention of water in the cold traps. We investigate those effects by simulating the evolution of a column of regolith in the region of permanent shadow over time. We determine the hydrogen concentration as a function of depth using a Monte Carlo model of discrete impacts and of delivery from the solar wind. We treat the delivery, sublimation, sputtering, and very small scale impacts as continual processes. Comparing the amount of water delivered to the poles to the amount remaining after space weathering, we find a retention efficiency of 5.6%. The retention efficiency of the polar cold traps is adequate for preserving volatile deposits over long periods of time. The average hydrogen concentration in the regolith column is 4100 ppm in the top meter after 1 Gyr. This is a saturation level in the regolith. Increasing the amount of time deepens the enriched layer but does not lead to increased concentrations. In 1 Gyr, about 1.6 m of the regolith is gardened. Therefore the top meter, which is probed by the neutron spectroscopy technique, has reached steady state in the simulations. The 4100 ppm saturation level is about half of the amount of hydrogen inferred from the Lunar Prospector neutron data. C1 Catholic Univ Amer, Dept Phys, Washington, DC 20064 USA. NASA, Extraterr Phys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Crider, DH (reprint author), 106 Driftwood Dr, Gibsonville, NC 27249 USA. RI Hurley, Dana/F-4488-2015 OI Hurley, Dana/0000-0003-1052-1494 NR 46 TC 39 Z9 39 U1 0 U2 7 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 JUL 30 PY 2003 VL 108 IS E7 AR 5079 DI 10.1029/2002JE002030 PG 11 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 710XH UT WOS:000184707800002 ER PT J AU Meador, MAB Cubon, VA Scheiman, DA Bennett, WR AF Meador, MAB Cubon, VA Scheiman, DA Bennett, WR TI Effect of branching on rod-coil block polyimides as membrane materials for lithium polymer batteries SO CHEMISTRY OF MATERIALS LA English DT Article ID SIDE-CHAINS; ELECTROLYTES; COPOLYMERS; TRANSPORT AB This paper describes a series of rod-coil block copolymers that produce easy-to-fabricate, dimensionally stable films with good ionic conductivity over a range of temperatures for use as electrolytes for lithium polymer batteries. The polymers consist of short, rigid rod polyimide segments alternating with flexible, polyalkylene oxide coil segments. Am optimization study was carried out to examine the effects of four variables (degree of branching, formulated molecular weight, polymerization solvent, and lithium salt concentration) on ionic conductivity, glass transition temperature, and dimensional stability in this system. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Meador, MAB (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. OI Meador, Mary Ann/0000-0003-2513-7372 NR 12 TC 22 Z9 22 U1 1 U2 13 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 JUL 29 PY 2003 VL 15 IS 15 BP 3018 EP 3025 DI 10.1021/cm0301726 PG 8 WC Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA 705DF UT WOS:000184379900026 ER PT J AU Stoner, AW Titgen, RH AF Stoner, AW Titgen, RH TI Biological structures and bottom type influence habitat choices made by Alaska flatfishes SO JOURNAL OF EXPERIMENTAL MARINE BIOLOGY AND ECOLOGY LA English DT Article DE habitat complexity; habitat preference; behavior; halibut; rock sole; crypsis ID PLAICE PLEURONECTES-PLATESSA; GENERALIZED ADDITIVE-MODELS; EASTERN BERING SEA; COD GADUS-MORHUA; CONTINENTAL-SHELF; JUVENILE PLAICE; WINTER FLOUNDER; ABIOTIC FACTORS; FLOOR HABITAT; PREDATION AB Habitats of flatfishes are ordinarily characterized on the basis of depth, sediment type, and temperature. However, features of the benthic environment such as structures created by sessile organisms and different bedforms may also influence habitat suitability. In this investigation, we tested the hypothesis that habitat choices made by juveniles of two economically important flatfishes, Pacific halibut (Hippoglossus stenolepis Schmidt) and northern rock sole (Lepidopsetta polyxystra Orr and Matarese), are influenced by structures on the sea floor. In the laboratory, age-0 individuals of both species demonstrated high positive selectivity for habitats with structure (natural sponges, bryozoan mimics, bivalve shells, and sand waves) over smooth sand substratum. The degree of choice was influenced significantly by density of structures, particularly sponges. Small halibut (4877 and 90-144 mm) were more selective than larger juveniles (270-337 mm), and in sponge habitat juvenile halibut were more selective than comparably sized rock sole. Preference for habitat with structure increased significantly with increasing light level, suggesting that choices were made partially on the basis of visual cues or as related to perceived threat. However, the preference for structured habitat was maintained in darkness. Beam trawl collections made in a flatfish nursery ground near Kodiak, Alaska, revealed that the abundances of age-0 Pacific halibut and rock sole were closely correlated with amounts of shell and echinoderm bycatch in the tows, corroborating the laboratory observations of affinity for habitat structure. Strong preferences for structured habitat in young halibut and rock sole indicate the importance of benthic structures that are frequently removed by fishing gear. Published by Elsevier Science B.V C1 Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr, Fisheries Behav Ecol Program, NOAA, Newport, OR 97365 USA. RP Stoner, AW (reprint author), Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr, Fisheries Behav Ecol Program, NOAA, 2030 S Marine Sci Dr, Newport, OR 97365 USA. NR 53 TC 51 Z9 52 U1 2 U2 12 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 JUL 29 PY 2003 VL 292 IS 1 BP 43 EP 59 DI 10.1016/S0022-0981(03)00144-8 PG 17 WC Ecology; Marine & Freshwater Biology SC Environmental Sciences & Ecology; Marine & Freshwater Biology GA 693LX UT WOS:000183720000003 ER PT J AU Crawford, J Shetter, RE Lefer, B Cantrell, C Junkermann, W Madronich, S Calvert, J AF Crawford, J Shetter, RE Lefer, B Cantrell, C Junkermann, W Madronich, S Calvert, J TI Cloud impacts on UV spectral actinic flux observed during the International Photolysis Frequency Measurement and Model Intercomparison (IPMMI) SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE clouds; photolysis; actinic flux; UV; radiation ID OBSERVATORY PHOTOCHEMISTRY EXPERIMENT; PACIFIC EXPLORATORY MISSION; OZONE PRODUCTION; MULTIPLE-SCATTERING; TROPICAL PACIFIC; B RADIATION; TRANSMITTANCE; EMISSIONS; OXIDANTS; PROGRAM AB [1] Observations collected during the International Photolysis Frequency Measurement and Model Intercomparison (IPMMI) have enabled a semiquantitative assessment of cloud impacts on UV spectral actinic flux. Critical to this analysis is the availability of spectroradiometer data accompanied by sky camera images. Data reveal several interesting aspects of cloud influences. Enhancements in UV actinic flux of up to 40% over clear-sky values are observed for cloudy conditions when the solar disk is unoccluded. When the solar disk is occluded, reductions in actinic flux appear to vary inversely with cloud fraction in some instances. A wavelength dependence is also observed with shorter wavelengths generally exhibiting lower variability for both enhancements and reductions (e.g., 20-30% less variability at 320 versus 420 nm). Enhancements in actinic flux show a stronger wavelength dependence with increasing cloud fraction. By contrast, wavelength dependence appears to weaken with increasing cloud fraction for actinic flux reduction. At low Sun, however, a wavelength dependence appears to occur even for overcast conditions. Despite these differences, integration over longer periods shows cloud impacts on actinic flux to be similar for all UV wavelengths, suggesting that differences in wavelength response are localized phenomena with impacts that are minimized when integrated over the surrounding area. Further studies at other latitudes and in other seasons are needed to verify this behavior. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. Natl Ctr Atmospher Res, Div Atmospher Chem, Boulder, CO 80304 USA. Fraunhofer Inst Atmosphar Umweltforsch, D-82467 Garmisch Partenkirchen, Germany. RP Crawford, J (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. EM j.h.crawford@larc.nasa.gov; shetter@ucar.edu; cantrell@ncar.ucar.edu; wolfgang.jumkermann@imk.fzk.de; sasha@acd.ucar.edu; calvert@acd.ucar.edu RI Junkermann, Wolfgang/A-7416-2013; Crawford, James/L-6632-2013; Garmisch-Pa, Ifu/H-9902-2014; Madronich, Sasha/D-3284-2015; Lefer, Barry/B-5417-2012 OI Crawford, James/0000-0002-6982-0934; Madronich, Sasha/0000-0003-0983-1313; Lefer, Barry/0000-0001-9520-5495 NR 36 TC 37 Z9 37 U1 2 U2 6 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 JUL 29 PY 2003 VL 108 IS D14 AR 8545 DI 10.1029/2002JD002731 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 710WX UT WOS:000184706800003 ER PT J AU Lin, B Minnis, P Fan, A AF Lin, B Minnis, P Fan, A TI Cloud liquid water path variations with temperature observed during the Surface Heat Budget of the Arctic Ocean (SHEBA) experiment SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID OPTICAL-THICKNESS; VISIBLE MEASUREMENTS; SATELLITE MICROWAVE; CIRRUS CLOUDS; IRIS; DEPENDENCE; FEEDBACK; MODELS AB [1] Because clouds play such a significant role in climate, understanding their responses to climatic temperature changes is essential to determining the overall impact of a given climate forcing. Cloud liquid water path (LWP) over tropical and midlatitude oceans has been observed to decrease with increasing cloud temperature. The presence of an ice sheet over the Arctic Ocean alters the energy and moisture exchange between the ocean and the atmospheric boundary layer and thus may affect the relationship between LWP and temperature. The variations of LWP with cloud and surface temperatures are examined in this paper using a combination of surface and satellite data taken during the 1998 Surface Heat Budget of the Arctic Ocean and the FIRE Arctic Clouds Experiments. The results show that LWP increases with temperature primarily because of an increase in cloud thickness that is enabled by the rise in surface moisture during the melt season. Cloud base heights and lifting condensation levels decrease as a result of the greater surface relative humidity and temperature. The average change rate of LWP with cloud temperature is 3.3% K-1, a value slightly smaller than earlier observations taken over cold midlatitude land areas. This cloud LWP feedback with temperature differs significantly from that estimated over other marine environments and should be taken into account in all climate models with explicit cloud feedbacks. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. Sci Applicat Int Corp, Hampton, VA 23666 USA. RP Lin, B (reprint author), NASA, Langley Res Ctr, MS 420, Hampton, VA 23681 USA. EM bing.lin-1@nasa.gov RI Minnis, Patrick/G-1902-2010 OI Minnis, Patrick/0000-0002-4733-6148 NR 27 TC 11 Z9 13 U1 0 U2 3 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 JUL 29 PY 2003 VL 108 IS D14 AR 4427 DI 10.1029/2002JD002851 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 710WX UT WOS:000184706800004 ER PT J AU Roads, J Chen, S Cocke, S Druyan, L Fulakeza, M LaRow, T Lonergan, P Qian, JH Zebiak, S AF Roads, J Chen, S Cocke, S Druyan, L Fulakeza, M LaRow, T Lonergan, P Qian, JH Zebiak, S TI International Research Institute/Applied Research Centers (IRI/ARCs) regional model intercomparison over South America SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE regional climate modeling; Brazil; South America ID GENERAL-CIRCULATION MODEL; CLIMATE-MODEL; BOUNDARY-LAYER; SPECTRAL MODEL; UNITED-STATES; 2XCO(2) SIMULATIONS; MONSOON CLIMATE; SOLAR-RADIATION; EASTERN ASIA; PART I AB [1] A regional modeling intercomparison project for South America among the ( 1) Scripps Experimental Climate Prediction Center regional spectral model (RSM), ( 2) Florida State University nested regional spectral model (FSUNRSM), ( 3) Goddard Institute for Space Studies regional climate model (RCM), and ( 4) IRI regional climate model (RegCM2) is described herein. All regional models were driven by the NCEP/ NCAR I global reanalysis over a South American domain centered on Brazil. In comparison to new Xie and Arkin 0.5degrees land observations, the regional models had a seasonal systematic precipitation error that was somewhat similar to the driving NCEP/ NCAR reanalysis systematic error, although the regional model ensemble mean error was somewhat smaller, indicating a potential value for using multiple model ensembles. However, correlations, threat scores and biases were not noticeably better. In short, at their current levels of skill, regional models do not yet provide a noticable improvement over large-scale analyses. C1 Univ Calif San Diego, Scripps Inst Oceanog, Expt Climate Predict Ctr, La Jolla, CA 92023 USA. Florida State Univ, COAPS, Tallahassee, FL 32306 USA. Columbia Univ, Earth Inst, New York, NY 10025 USA. NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Columbia Univ, Lamont Doherty Earth Observ, Int Res Inst, Palisades, NY 10964 USA. RP Roads, J (reprint author), Univ Calif San Diego, Scripps Inst Oceanog, Expt Climate Predict Ctr, 0224, La Jolla, CA 92023 USA. EM jroads@ucsd.edu NR 68 TC 29 Z9 32 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 JUL 29 PY 2003 VL 108 IS D14 AR 4425 DI 10.1029/2002JD003201 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 710WX UT WOS:000184706800008 ER PT J AU Burrage, DM Steinberg, CR Mason, LB Bode, L AF Burrage, DM Steinberg, CR Mason, LB Bode, L TI Tidal corrections for TOPEX altimetry in the Coral Sea and Great Barrier Reef Lagoon: Comparisons with long-term tide gauge records SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article DE TOPEX; altimetry; tides; corrections; Coral Sea; Great Barrier Reef ID GLOBAL OCEAN TIDES; TOPEX/POSEIDON ALTIMETRY; SATELLITE ALTIMETER; CONTINENTAL-SHELF; GEOSAT ALTIMETRY; SURFACE HEIGHT; CIRCULATION; CALIBRATION; PACIFIC; MODEL AB [ 1] The well-known capability of TOPEX/Poseidon altimetry to map sea levels precisely in the deep oceans motivates its application to the topographically complex Coral Sea and NE Australian continental margin. We assess several global tidal models for correcting TOPEX altimetry in the Coral Sea and find CSR3.0 offers good overall performance, based on comparisons of model-predicted and tide gauge harmonic constituents. Using CSR3.0 tidal corrections, we evaluate residual Sea Surface Height (SSH) Root Mean Square (RMS) variability and residual M2 tidal alias errors. Away from large reefs and islands, CSR3.0 amplitude and phase errors for M2 are typically less than 5 cm and 8 deg, respectively, with RMS tidal errors of 5 cm or less and RMS SSH residuals approximating 10 cm. Since model deficiencies appear in the macro-tidal region of the Southern Great Barrier Reef Lagoon, near Broad Sound, we employ a high-resolution hydrodynamic model in this area to compute the tidal corrections. Predicted M2 amplitude and phase in this region are within 3 cm and 5 deg of observations, RMS errors are mostly under 4 cm and coastal RMS SSH residuals are as low as 15 cm, in spite of coastal trapped waves and submesocale eddies in the Lagoon. Daily and monthly smoothed SSH residual time series, respectively, yield optimal lagged correlations with in situ sea level data in the range 0.3 - 0.9 and 0.6 - 0.9 for locations spanning the Coral Sea and in the Lagoon. Lag correlations of monthly smoothed Geostrophic Current Anomalies derived from TOPEX SSH gradients with long-term currents from the continental slope yield optimal correlations of 0.5 and 0.8, respectively, near Jewell ( lat 14 deg S) and Myrmidon Reef ( 19 deg S). Our results demonstrate that low-frequency sea level and geostrophic current variations can be reliably observed using altimetry over the Coral Sea and NE Australian continental slope, and for selected locations on the continental shelf, if appropriate tide correction models are employed. C1 Australian Inst Marine Sci, Townsville, Qld 4810, Australia. James Cook Univ N Queensland, Sch Engn, Townsville, Qld 4811, Australia. James Cook Univ N Queensland, Sch Math & Phys Sci, Townsville, Qld 4811, Australia. James Cook Univ N Queensland, Cooperat Res Ctr Great Barrier Reef World Heritag, CRC Reef Res Ctr Ltd, Townsville, Qld, Australia. RP Burrage, DM (reprint author), Univ So Mississippi, Dept Marine Sci, Stennis Space Ctr, Box 1020, Mississippi State, MS 39529 USA. RI Bode, Lance/A-1294-2010 NR 62 TC 3 Z9 3 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-OCEANS JI J. Geophys. Res.-Oceans PD JUL 29 PY 2003 VL 108 IS C7 AR 3241 DI 10.1029/2000JC000441 PG 21 WC Oceanography SC Oceanography GA 710XC UT WOS:000184707300001 ER PT J AU Burlaga, LF Wang, C Richardson, JD Ness, NF AF Burlaga, LF Wang, C Richardson, JD Ness, NF TI Evolution of the multiscale statistical properties of corotating streams from 1 to 95 AU SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article DE corotating streams; large-scale fluctuations; solar wind ID VELOCITY STRUCTURE FUNCTIONS; MERGED INTERACTION REGIONS; SOLAR-WIND; OUTER HELIOSPHERE; MAGNETIC-FIELD; PICKUP IONS; INTERMITTENT TURBULENCE; DISTANT HELIOSPHERE; SPEED FLUCTUATIONS; SHOCK PROPAGATION AB [1] This paper discusses the multiscale structure of the large-scale speed fluctuations between 1 and 95 AU during the declining phase of the solar cycle, when corotating streams are dominant structures close to the Sun. A deterministic, multifluid, one-dimensional MHD model with the WIND data at 1 AU during 1995 as input was used to compute the time series of daily averages of speed, V(t(i)), with a length on the order of 1 year at R = 5, 10,... 95 AU, from which we calculated various statistical functions describing the solar wind speed. The probability distribution functions (PDFs) of the running speed differences dVn(t(i)) were calculated at scales tau from 1 to 64 days. The theoretical PDFs at 50 AU have the same qualitative forms as those observed by Voyager 2 (V2) between 46 and 49 AU. The theoretical PDF at a scale of 1 day at 15 AU agrees with the corresponding PDF observed by V2 between 13 and 16 AU. With increasing distance from the Sun, the width of the predicted PDF with t = 1 decreases and the tail becomes more prominent. The standard deviation of dVn( ti) at various R computed from the model, SD(tau, R), decreases nearly exponentially with increasing R, and it is consistent with the observations of SD( t, R) made by V2 near 15 and 50 AU. The skewness at a scale of 1 day increases almost linearly with R beyond approximate to35 AU, but it shows structure between 5 and 35 AU; it is consistent with the observations of V2 near 15 and 50 AU. The theoretical power spectral density of the speed fluctuations, PSD(f, R), agrees with the observations of V2 near 15 and 50 AU. For frequencies f > 8.5 x 10(-7) Hz, PSD(f, R) proportional to f(-s(R)). The observed and predicted s are less than or equal to - 2 beyond 40 AU, consistent with the jump-ramp structure of V( t) in the distant heliosphere. We predict that the PDFfor tau = 1 which will be observed by V2 at 70 AU in 2003 will have a core whose width is only approximate to 5 km/ s and a tail extending up to 60 km/ s that represents the major jumps in the speed profile. The predicted PDF at 95 AU is very similar to that at 70 AU. The model predicts that most speed jumps at 15 and 70 AU will have the signature of forward shocks and reverse shocks. The amplitudes of the large and moderate speed jumps diminish as they move from 45 to 95 AU. Some speed jumps move through this region without interacting with other speed jumps. In a few cases, neighboring speed jumps merge between 45 and 95 AU. The structure of the solar wind changes slowly as it moves from 45 to 95 AU. C1 NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. MIT, Ctr Space Res, Cambridge, MA 02139 USA. Univ Delaware, Bartol Res Inst, Newark, DE 19716 USA. RP Burlaga, LF (reprint author), NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Mail Code 692,Bldg 21,Room 244, Greenbelt, MD 20771 USA. NR 45 TC 10 Z9 10 U1 0 U2 2 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 JUL 29 PY 2003 VL 108 IS A7 AR 1305 DI 10.1029/2003JA009841 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 710YM UT WOS:000184710400003 ER PT J AU Yang, RQ Qiu, YM AF Yang, RQ Qiu, YM TI Bipolar cascade lasers at emitting wavelengths near 2 mu m SO APPLIED PHYSICS LETTERS LA English DT Article ID JUNCTIONS AB Broad-area InGaAs/InP-based bipolar cascade lasers were demonstrated at emitting wavelengths near 2 mum and their spectral characteristics were investigated. These broad-area lasers operated at temperatures up to 205 K in continuous wave mode and up to room temperature in pulsed mode. Distinct spectral features were observed at high temperatures with larger currents and bias, which may result from significant Stark effects and increased excited state transitions. (C) 2003 American Institute of Physics. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Yang, RQ (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 9 TC 2 Z9 2 U1 0 U2 0 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 JUL 28 PY 2003 VL 83 IS 4 BP 599 EP 601 DI 10.1063/1.1595713 PG 3 WC Physics, Applied SC Physics GA 704JM UT WOS:000184336600003 ER PT J AU Betts, AK Ball, JH Bosilovich, M Viterbo, P Zhang, YC Rossow, WB AF Betts, AK Ball, JH Bosilovich, M Viterbo, P Zhang, YC Rossow, WB TI Intercomparison of water and energy budgets for five Mississippi subbasins between ECMWF reanalysis (ERA-40) and NASA Data Assimilation Office fvGCM for 1990-1999 SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE precipitation; surface energy budgets; Mississippi basin budgets; reanalysis ID LAND-SURFACE PARAMETERIZATION; ATMOSPHERE RADIATIVE FLUXES; LARGE-SCALE MODELS; ISCCP DATA SETS; SOIL-MOISTURE; CIRCULATION MODEL; UNITED-STATES; RIVER-BASIN; SENSITIVITY; IMPACT AB [1] Using monthly means for 1990-1999, we assess the systematic biases in temperature and humidity and the surface energy and water budgets of both European Centre for Medium-Range Weather Forecasts (ECMWF) 40-year reanalysis (ERA-40) and the of the NASA Data Assimilation Office atmospheric finite-volume general circulation model (fvGCM) for five Mississippi subbasins. We compare ERA-40 and the fvGCM with basin averages of surface observations of temperature, humidity and precipitation, the river basin estimates for the hydrological balance from Maurer et al. [2002], and the International Satellite Cloud Climatology Project (ISCCP) retrieved skin temperature and surface radiation fluxes. We show the role of the soil water analysis in ERA-40, which generally supplies water in summer and removes it in winter and spring. The ERA-40 snow analysis increments are a significant contribution to the ( smaller) frozen water budget. Compared with National Climate Data Center (NCDC) observations of screen temperature, ERA-40 generally has a relatively small (less than or equal to 1 K) positive temperature bias in all seasons for the Mississippi basins, while the fvGCM has a large cold bias in temperature in winter. The ISCCP skin temperature estimate is generally high in winter and a little low in summer, compared to ERA-40 and the NCDC screen level temperature. For the western basins, summer precipitation is high in the fvGCM, while for the eastern basins it is high in ERA-40 (in 12-24 hour forecasts after spin-up). Summer evaporation is higher in the fvGCM than in ERA-40, while winter evaporation has a high bias in ERA-40, leading to a corresponding high bias in specific humidity. Net shortwave radiation probably has a high bias in the fvGCM in summer. The seasonal cycle of incoming shortwave is much flatter in ERA-40 than the ISCCP data, suggesting that the reanalysis may have too much reflective cloud in summer and too little in the cooler seasons. The temperature biases at the surface in both the fvGCM and the ISCCP data clearly have a negative impact on the surface long-wave radiation fluxes, although the bias in the net long-wave flux is rather less. C1 Atmospher Res, Pittsford, VT 05763 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. European Ctr Medium Range Weather Forecasts, Reading RG2 9AX, Berks, England. Columbia Univ, Dept Appl Phys & Appl Math, New York, NY 10025 USA. NASA, Goddard Inst Space Studies, New York, NY 10025 USA. RP Betts, AK (reprint author), Atmospher Res, 58 Hendee Lane, Pittsford, VT 05763 USA. EM akbetts@aol.com; mikeb@dao.gsfc.nasa.gov; p.viterbo@ecmwf.int; clyxz@mistral.giss.nasa.gov; wrossow@giss.nasa.gov RI Viterbo, Pedro/B-7184-2008; Bosilovich, Michael/F-8175-2012; Rossow, William/F-3138-2015 OI Viterbo, Pedro/0000-0001-6587-3062; NR 30 TC 53 Z9 53 U1 0 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 JUL 26 PY 2003 VL 108 IS D16 AR 8618 DI 10.1029/2002JD003127 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 709EP UT WOS:000184612000001 ER PT J AU Yang, JN Lei, Y Pan, SW Huang, N AF Yang, JN Lei, Y Pan, SW Huang, N TI System identification of linear structures based on Hilbert-Huang spectral analysis. Part 1: normal modes SO EARTHQUAKE ENGINEERING & STRUCTURAL DYNAMICS LA English DT Article DE system identification; Hilbert transform; linear structures; normal modes; Hilbert-Huang spectral analysis ID TRANSFORM; DECOMPOSITION AB Based on the Hilbert-Huang spectral analysis, a method is proposed to identify multi-degree-of-freedom (MDOF) linear systems using measured free vibration time histories. For MDOF systems, the normal modes have been assumed to exist. In this method, the measured response data, which are polluted by noises, are first decomposed into modal responses using the empirical mode decomposition (EMD) approach with intermittency criteria. Then, the Hilbert transform is applied to each modal response to obtain the instantaneous amplitude and phase angle time histories. A linear least-square fit procedure is proposed to identify the natural frequency and damping ratio from the instantaneous amplitude and phase angle for each modal response. Based on a single measurement of the free vibration time history at one appropriate location, natural frequencies and damping ratios can be identified. When the responses at all degrees of freedom are measured, the mode shapes and the physical mass, damping and stiffness matrices of the structure can be determined. The applications of the proposed method are illustrated using three linear systems with different dynamic characteristics. Numerical simulation results demonstrate that the proposed system identification method yields quite accurate results, and it offers a new and effective tool for the system identification of linear structures in which normal modes exist. Copyright (C) 2003 John Wiley Sons, Ltd. C1 Univ Calif Irvine, Dept Civil & Environm Engn, Irvine, CA 92697 USA. NASA, Goddard Space Flight Ctr, Lab Hydrospher Proc, Greenbelt, MD 20771 USA. RP Yang, JN (reprint author), Univ Calif Irvine, Dept Civil & Environm Engn, Irvine, CA 92697 USA. RI Lei, ying/C-8567-2013 NR 39 TC 173 Z9 230 U1 1 U2 36 PU JOHN WILEY & SONS LTD PI CHICHESTER PA THE ATRIUM, SOUTHERN GATE, CHICHESTER PO19 8SQ, W SUSSEX, ENGLAND SN 0098-8847 J9 EARTHQUAKE ENG STRUC JI Earthq. Eng. Struct. Dyn. PD JUL 25 PY 2003 VL 32 IS 9 BP 1443 EP 1467 DI 10.1002/eqe.287 PG 25 WC Engineering, Civil; Engineering, Geological SC Engineering GA 705FA UT WOS:000184384000008 ER PT J AU Sud, YC Walker, GK AF Sud, YC Walker, GK TI Influence of ice-phase physics of hydrometeors on moist-convection SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID RELAXED ARAKAWA-SCHUBERT; SCHEME MCRAS; PARAMETERIZATION; MICROPHYSICS; CLOUDS; MODELS; GCM AB [1] The influence of ice-phase physics (IPP) of hydrometeors was isolated using three 3-year long simulations with the FvGCM employing parameterized cloud microphysics. The Control Case CC had no IPP, whereas the two experiments E1 and E2 invoked IPP with two different hydrometeor-freezing assumptions. Case E1 froze liquid hydrometeors at subfreezing temperatures at detrainment. Case E2 also froze new condensate generated at subfreezing temperatures of the cumulus updrafts. However, melting of falling frozen hydrometeors occurred at the very first encounter with above freezing temperatures in both simulations. Comparative analysis showed discernible differences in cloud and condensation heating climatologies of these simulations. Specifically, IPP influenced convective detrainment at mid- and deep-levels in accord with TOGA-COARE observations. The study suggests that IPP can mitigate less-than-observed mid-level clouds and overabundance of deep clouds and might invigorate cumulus-induced downdrafts. C1 NASA, Goddard Space Flight Ctr, Atmospheres Lab, Climate & Radiat Branch, Greenbelt, MD 20771 USA. SAIC Gen Sci Corp, Beltsville, MD USA. RP Sud, YC (reprint author), NASA, Goddard Space Flight Ctr, Atmospheres Lab, Climate & Radiat Branch, Greenbelt, MD 20771 USA. NR 18 TC 15 Z9 15 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 JUL 25 PY 2003 VL 30 IS 14 AR 1758 DI 10.1029/2003GL017587 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 709DU UT WOS:000184610100004 ER PT J AU Ho, SP Lin, B Minnis, P Fan, TF AF Ho, SP Lin, B Minnis, P Fan, TF TI Estimates of cloud vertical structure and water amount over tropical oceans using VIRS and TMI data SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE cloud; overlapped cloud; LWP; TMI; VIRS ID UPPER-AIR OBSERVATIONS; VISIBLE MEASUREMENTS; SATELLITE MICROWAVE; FIRE-II; LIQUID; STATISTICS; VERIFICATION; COMBINATION; RAWINSONDE; OVERLAP AB [1] A microwave, visible and infrared (MVI) method was applied to coincident, collocated Tropical Rainfall Measuring Mission (TRMM) Microwave Imager (TMI) and VIRS ( Visible and Infrared Scanner) data collected from January to August 1998 to estimate the cloud vertical structure and water path over tropical oceans. The derived quantities include the liquid water path ( LWP), ice water path (IWP), total water path (WP), the frequencies of single-layer and overlapping nonprecipitating clouds, and the cloud top-height, base-height and thickness for single-layered water clouds. LWP data retrieved from TMI measurements were compared with global and regional LWP retrieved from VIRS for warm nonprecipitating clouds for different seasons. The global mean difference between TMI LWP and VIRS LWP is less than 0.01 mm and varies with season. For cold clouds, the TMI LWP is only 25 - 30% of the VIRS WP. In these cases, the ice clouds observed by VIRS overlap liquid water clouds. This result is similar to that from an earlier study, however, the well-matched TMI and VIRS data provide more accurate instantaneous estimates than were previously possible. The assumption, that the cloud is entirely ice, used to compute IWP introduces some errors in the WP because of cloud overlapping. However, the difference between IWP estimated for all TMI FOVs containing only ice-phase VIRS pixels and the IWP estimated from the difference between the VIRS WP and TMI LWP is less than 10%. This result suggests that IWP is independent of the lower-level clouds for nonprecipitating systems. For warm single-layered clouds, the estimated low-cloud-base altitudes (similar to 800m) and thicknesses ( between 800 m to 1000 m) are, on average, very close to low-cloud results derived from combined surface and upper-air observations. The frequency of overlapped nonprecipitating clouds over ocean was about 4%, 16% and 38% for low, middle, and high clouds, respectively. The results clearly demonstrate the potential for enhanced monitoring of maritime clouds using infrared, solar, and microwave imagers on the same platform. C1 Natl Ctr Atmospher Res, Div Atmospher Chem, Boulder, CO 80307 USA. NASA, Langley Res Ctr, Hampton, VA 23665 USA. SAIC, Hampton, VA USA. RP Ho, SP (reprint author), Natl Ctr Atmospher Res, Div Atmospher Chem, POB 3000, Boulder, CO 80307 USA. EM spho@ucar.edu; b.lin@larc.nasa.gov; p.minnis@larc.nasa.gov; t.f.fan@larc.nasa.gov RI Minnis, Patrick/G-1902-2010 OI Minnis, Patrick/0000-0002-4733-6148 NR 39 TC 21 Z9 21 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 JUL 25 PY 2003 VL 108 IS D14 AR 4419 DI 10.1029/2002JD003298 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 709EL UT WOS:000184611700001 ER PT J AU Ozgokmen, TM Molcard, A Chin, TM Piterbarg, LI Griffa, A AF Ozgokmen, TM Molcard, A Chin, TM Piterbarg, LI Griffa, A TI Assimilation of drifter observations in primitive equation models of midlatitude ocean circulation SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article DE Lagrangian data assimilation; data assimilation; drifter assimilation; ocean prediction; ocean modeling ID TROPICAL PACIFIC-OCEAN; SEA-SURFACE HEIGHT; NORTH-ATLANTIC; LAGRANGIAN DATA; ADRIATIC SEA; NUMERICAL-SIMULATION; TURBULENT FLOWS; DOUBLE-GYRE; PREDICTION; PREDICTABILITY AB [1] Motivated by increases in the realism of OGCMs and the number of drifting buoys in the ocean observing system, a new Lagrangian assimilation technique is implemented in an idealized, reduced-gravity configuration of the layered primitive equation model MICOM. Using an extensive set of twin experiments, the effectiveness of the Lagrangian observation operator and of a dynamical balancing technique for corrected model variables, which is based on geostrophy and mass conservation, are explored in comparison to a conventional Pseudo-Lagrangian observation operator and an implementation of the Kalman filter method. The results clearly illustrate that the Lagrangian observation operator is superior to the Pseudo-Lagrangian in the parameter range that is relevant for typical oceanic drifter observations, and that the simple dynamical balancing technique works well for midlatitude ocean circulation. C1 Univ Miami, Rosenstiel Sch Marine & Atmospher Sci, Miami, FL 33149 USA. Univ So Calif, Ctr Appl Math Sci, Los Angeles, CA 90089 USA. CNR, IOF, La Spezia, Italy. CALTECH, Jet Prop Lab, Pasadena, CA USA. RP Ozgokmen, TM (reprint author), Univ Miami, Rosenstiel Sch Marine & Atmospher Sci, 4600 Rickenbacker Causeway, Miami, FL 33149 USA. NR 42 TC 26 Z9 26 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-OCEANS JI J. Geophys. Res.-Oceans PD JUL 25 PY 2003 VL 108 IS C7 AR 3238 DI 10.1029/2002JC001719 PG 17 WC Oceanography SC Oceanography GA 709EZ UT WOS:000184613100001 ER PT J AU Abazajian, KN Dodelson, S AF Abazajian, KN Dodelson, S TI Neutrino mass and dark energy from weak lensing SO PHYSICAL REVIEW LETTERS LA English DT Article ID MICROWAVE BACKGROUND-RADIATION; POWER SPECTRUM; WEIGHING NEUTRINOS; GALAXIES; SUPERNOVAE; CONSTANT; UNIVERSE; SCALES; LIMITS; MATTER AB Weak gravitational lensing of background galaxies by intervening matter directly probes the mass distribution in the Universe. This distribution is sensitive to both the dark energy and neutrino mass. We examine the potential of lensing experiments to measure features of both simultaneously. Focusing on the radial information contained in a future deep 4000 deg(2) survey, we find that the expected (1-sigma) error on a neutrino mass is 0.1 eV, if the dark-energy parameters are allowed to vary. The constraints on dark-energy parameters are similarly restrictive, with errors on w of 0.09. C1 NASA, Fermilab Astrophys Ctr, Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. Univ Chicago, Dept Astron & Astrophys, Chicago, IL 60637 USA. RP NASA, Fermilab Astrophys Ctr, Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. NR 44 TC 100 Z9 100 U1 0 U2 16 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 EI 1079-7114 J9 PHYS REV LETT JI Phys. Rev. Lett. PD JUL 25 PY 2003 VL 91 IS 4 AR 041301 DI 10.1103/PhysRevLett.91.041301 PG 4 WC Physics, Multidisciplinary SC Physics GA 704ZR UT WOS:000184372300005 PM 12906650 ER PT J AU Yurtsever, U AF Yurtsever, U TI Holographic entropy bound and local quantum field theory SO PHYSICAL REVIEW LETTERS LA English DT Article ID PRINCIPLE AB I show how the holographic entropy bound can be derived from elementary flat-spacetime quantum field theory when the total energy of Fock states is constrained gravitationally. This energy constraint makes the Fock space dimension (whose logarithm is the maximum entropy) finite for both bosons and fermions. Despite the elementary nature of my analysis, it results in an upper limit on entropy in remarkable agreement with the holographic bound, and also provides a microscopic deviation of a more general entropy bound recently introduced by Gour. C1 CALTECH, Jet Prop Lab, Quantum Comp Technol Grp, Pasadena, CA 91109 USA. RP Yurtsever, U (reprint author), CALTECH, Jet Prop Lab, Quantum Comp Technol Grp, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 12 TC 20 Z9 20 U1 0 U2 0 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 JUL 25 PY 2003 VL 91 IS 4 AR 041302 DI 10.1103/PhysRevLett.91.041302 PG 4 WC Physics, Multidisciplinary SC Physics GA 704ZR UT WOS:000184372300006 PM 12906651 ER PT J AU Kounaves, SP Lukow, SR Comeau, BP Hecht, MH Grannan-Feldman, SM Manatt, K West, SJ Wen, XW Frant, M Gillette, T AF Kounaves, SP Lukow, SR Comeau, BP Hecht, MH Grannan-Feldman, SM Manatt, K West, SJ Wen, XW Frant, M Gillette, T TI Mars Surveyor Program '01 Mars Environmental Compatibility Assessment wet chemistry lab: A sensor array for chemical analysis of the martian soil SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article DE Mars; chemical analysis; electroanalysis; sensors; ISE ID ION-SELECTIVE ELECTRODES; BULK OPTODES; MODEL; ROCKS; SALTS AB [1] The Mars Environmental Compatibility Assessment (MECA) instrument was designed, built, and flight qualified for the now canceled MSP (Mars Surveyor Program) '01 Lander. The MECA package consisted of a microscope, electrometer, material patch plates, and a wet chemistry laboratory (WCL). The primary goal of MECA was to analyze the Martian soil (regolith) for possible hazards to future astronauts and to provide a better understanding of Martian regolith geochemistry. The purpose of the WCL was to analyze for a range of soluble ionic chemical species and electrochemical parameters. The heart of the WCL was a sensor array of electrochemically based ion-selective electrodes (ISE). After 20 months storage at -23degreesC and subsequent extended freeze/thawing cycles, WCL sensors were evaluated to determine both their physical durability and analytical responses. A fractional factorial calibration of the sensors was used to obtain slope, intercept, and all necessary selectivity coefficients simultaneously for selected ISEs. This calibration was used to model five cation and three anion sensors. These data were subsequently used to determine concentrations of several ions in two soil leachate simulants (based on terrestrial seawater and hypothesized Mars brine) and four actual soil samples. The WCL results were compared to simulant and soil samples using ion chromatography and inductively coupled plasma optical emission spectroscopy. The results showed that flight qualification and prolonged low-temperature storage conditions had minimal effects on the sensors. In addition, the analytical optimization method provided quantitative and qualitative data that could be used to accurately identify the chemical composition of the simulants and soils. The WCL has the ability to provide data that can be used to "read'' the chemical, geological, and climatic history of Mars, as well as the potential habitability of its regolith. C1 Tufts Univ, Dept Chem, Medford, MA 02155 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. ThermoOrion, Beverly, MA 01915 USA. RP Kounaves, SP (reprint author), Tufts Univ, Dept Chem, 62 Talbot Ave, Medford, MA 02155 USA. NR 24 TC 9 Z9 9 U1 0 U2 10 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 JUL 24 PY 2003 VL 108 IS E7 AR 5077 DI 10.1029/2002JE001978 PG 12 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 709FF UT WOS:000184614000001 ER PT J AU Gawronski, W AF Gawronski, W TI Discrete-time norms of flexible structures SO JOURNAL OF SOUND AND VIBRATION LA English DT Article ID PRINCIPAL COMPONENT ANALYSIS; MODEL-REDUCTION; LINEAR-SYSTEMS AB The paper presents and analyses the H-2, H-infinity, and Hankel norms of flexible structures. The analysis is conducted for the discrete-time models of structures and compared with the continuous-time results. The structural state-space models are presented in modal co-ordinates. Closed-form expressions for norms of structural modes are obtained, and norms of a structure are determined from the modal norms. The relationships between the Hankel, H-infinity, and H-2 modal norms are derived. In addition, the paper shows that the discrete-time Hankel and H-infinity norms converge to the continuous-time counterparts when the sampling time approaches zero; however, the H-2 norm does not. (C) 2002 Elsevier Science Ltd. All rights reserved. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Gawronski, W (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 238-528, Pasadena, CA 91109 USA. NR 15 TC 3 Z9 3 U1 0 U2 0 PU ACADEMIC PRESS LTD ELSEVIER SCIENCE LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 0022-460X J9 J SOUND VIB JI J. Sound Vibr. PD JUL 24 PY 2003 VL 264 IS 5 BP 983 EP 1004 DI 10.1016/S0022-460X(02)01184-7 PG 22 WC Acoustics; Engineering, Mechanical; Mechanics SC Acoustics; Engineering; Mechanics GA 702CQ UT WOS:000184208100001 ER PT J AU Bellouin, N Boucher, O Tanre, D Dubovik, O AF Bellouin, N Boucher, O Tanre, D Dubovik, O TI Aerosol absorption over the clear-sky oceans deduced from POLDER-1 and AERONET observations SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article AB [1] We estimate aerosol absorption over the clear-sky oceans using aerosol geophysical products from POLDER-1 space measurements and absorption properties from ground-based AERONET measurements. Our best estimate is 2.5 Wm(-2) averaged over the 8-month lifetime of POLDER-1. Low and high absorption estimates are 2.2 and 3.1 Wm(-2) based on the variability in aerosol single-scattering albedo observed by AERONET. Main sources of uncertainties are the discrimation of the aerosol type from satellite measurements, and potential clear-sky bias induced by the cloud-screening procedure. C1 Univ Sci & Tech Lille Flandres Artois, CNRS UMR 8518, Opt Atmospher Lab, F-59655 Villeneuve Dascq, France. NASA, Goddard Space Flight Ctr, Terr Phys Lab, Greenbelt, MD 20771 USA. RP Bellouin, N (reprint author), Univ Sci & Tech Lille Flandres Artois, CNRS UMR 8518, Opt Atmospher Lab, F-59655 Villeneuve Dascq, France. RI Dubovik, Oleg/A-8235-2009; Boucher, Olivier/J-5810-2012; Boucher, Olivier/K-7483-2012; OI Dubovik, Oleg/0000-0003-3482-6460; Boucher, Olivier/0000-0003-2328-5769; Boucher, Olivier/0000-0003-2328-5769; Bellouin, Nicolas/0000-0003-2109-9559 NR 16 TC 34 Z9 36 U1 1 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 JUL 23 PY 2003 VL 30 IS 14 AR 1748 DI 10.1029/2003GL017121 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 709DP UT WOS:000184609700001 ER PT J AU Chen, D Liu, WT Tang, WQ Wang, ZR AF Chen, D Liu, WT Tang, WQ Wang, ZR TI Air-sea interaction at an oceanic front: Implications for frontogenesis and primary production SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID SURFACE TEMPERATURE; EAST CHINA; VARIABILITY; YELLOW; MODEL AB [1] Based on recent satellite observations, we hypothesize that there exists a significant air-sea interaction at the shelf-break front in the East China Sea. An idealized ocean-atmosphere coupled model was designed to test this hypothesis and to study the physical processes involved in such an interaction, with emphasis on the oceanic part. A positive feedback between ocean and atmosphere was identified in the model and its consequences were evaluated. We found that air-sea interaction, when combined with sloping topography, could provide a mechanism for the genesis of the shelf-break front. The resulting frontal circulation and vertical mixing could bring nutrient-rich subsurface water into the surface euphotic zone, thus making the frontal region a conspicuous place for primary production. C1 Columbia Univ, Lamont Doherty Geol Observ, Palisades, NY 10964 USA. Jet Prop Lab, Pasadena, CA USA. RP Chen, D (reprint author), Columbia Univ, Lamont Doherty Geol Observ, POB 1000, Palisades, NY 10964 USA. RI Chen, Dake/E-7082-2011 NR 7 TC 18 Z9 18 U1 0 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 JUL 23 PY 2003 VL 30 IS 14 AR 1745 DI 10.1029/2003GL017536 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 709DP UT WOS:000184609700003 ER PT J AU Levy, RC Remer, LA Tanre, D Kaufman, YJ Ichoku, C Holben, BN Livingston, JM Russell, PB Maring, H AF Levy, RC Remer, LA Tanre, D Kaufman, YJ Ichoku, C Holben, BN Livingston, JM Russell, PB Maring, H TI Evaluation of the Moderate-Resolution Imaging Spectroradiometer ( MODIS) retrievals of dust aerosol over the ocean during PRIDE SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE Saharan dust; aerosol; MODIS; PRIDE; Puerto Rico; Sun photometer ID SUN-PHOTOMETER MEASUREMENTS; SKY RADIANCE MEASUREMENTS; OPTICAL-DEPTH SPECTRA; NORTH-ATLANTIC OCEAN; SIZE DISTRIBUTION; MINERAL DUST; WATER-VAPOR; PERFORMANCE-CHARACTERISTICS; SAHARAN DUST; SATELLITE AB [1] The Puerto Rico Dust Experiment ( PRIDE) took place in Roosevelt Roads, Puerto Rico from 26 June to 24 July 2000 to study the radiative and physical properties of African dust aerosol transported into the region. PRIDE had the unique distinction of being the first major field experiment to allow direct comparison of aerosol retrievals from the Moderate Imaging Spectroradiometer ( MODIS) with Sun photometer and in situ aerosol measurements. Over the ocean the MODIS algorithm retrieves aerosol optical depth (AOD) as well as information about the aerosols' size distribution. During PRIDE, AODs derived by MODIS in the red wavelengths (0.66 mum) compare closely with Sun photometers. However, MODIS-derived AODs are too large in the blue and green wavelengths (0.47 and 0.55 mum) and too small in the near infrared (0.87 mum). This error in AOD spectral dependence results in retrieved particle size distributions that are small compared to in situ measurements and smaller still when compared to Sun photometer sky radiance inversions. The differences in size distributions may be, in part, associated with MODIS' simplification of dust as spherical particles. Analysis of this PRIDE data set is a first step toward derivation of realistic models for future MODIS retrievals. C1 Sci Syst & Applicat Inc, Lanham, MD 20706 USA. NASA, Goddard Space Flight Ctr, Terr Phys Lab, Greenbelt, MD 20771 USA. Univ Sci & Tech Lille, CNRS, Opt Atmospher Lab, F-59655 Villeneuve Dascq, France. SRI Int, Menlo Pk, CA 94025 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ Miami, Rosenstiel Sch Marine & Atmospher Sci, Miami, FL 33149 USA. RP Levy, RC (reprint author), Sci Syst & Applicat Inc, Lanham, MD 20706 USA. EM levy@climate.gsfc.nasa.gov RI Ichoku, Charles/E-1857-2012; Levy, Robert/M-7764-2013 OI Ichoku, Charles/0000-0003-3244-4549; Levy, Robert/0000-0002-8933-5303 NR 58 TC 119 Z9 120 U1 1 U2 10 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 JUL 23 PY 2003 VL 108 IS D19 AR 8594 DI 10.1029/2002JD002460 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 709EV UT WOS:000184612500001 ER PT J AU Weigel, RS Klimas, AJ Vassiliadis, D AF Weigel, RS Klimas, AJ Vassiliadis, D TI Solar wind coupling to and predictability of ground magnetic fields and their time derivatives SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article DE solar-wind driving; geomagnetic fields; geomagnetically induced currents; predictability; fluctuations ID LATITUDE ELECTRIC POTENTIALS; DATA-DERIVED ANALOGS; AURORAL ELECTROJET; GEOMAGNETIC-ACTIVITY; CURRENT SYSTEMS; POLAR-CAP; IONOSPHERIC ELECTRODYNAMICS; MAGNETOSPHERE INTERACTION; SUBSTORM DYNAMICS; NEURAL NETWORKS AB [1] A spatial and dynamic study of solar wind driving of high-latitude ground magnetic fields and their time derivatives is given. Nonlinear, data-derived basis functions are used to determine the optimal solar wind driven dynamic coupling function at high-latitude locations. The method does not assume a solar wind driving function a priori so that an unbiased determination of the relative influence of different driving processes can be made. Using this method, the locations where high-latitude models capture signatures of different driving processes, such as reconnection and the Kelvin-Helmholtz instability, are revealed for both the amplitude of the field and its time derivative. The time rate of change of the field is a disturbance measure related to geomagnetically induced currents. For the amplitude of the ground magnetic field the primary driver is reconnection; the time rate of change of the field has signatures of both reconnection driving in the nightside sector and Kelvin-Helmholtz driving in the prenoon sector. The independent influence of the solar wind ion density and azimuthal component of the magnetic field in driving magnetic field fluctuations is found to be small at auroral-zone latitudes. The data-derived coupling functions are also used to estimate the expected prediction error of a general class of models that specify the ground magnetic field or its time derivative given solar wind plasma measurements. Prediction efficiencies as small as zero and as large as 0.7 for both the amplitude of the field and its time derivative are possible. The prediction efficiency is highly dependent on spatial location and the direction of field being predicted. C1 NASA, Natl Res Council, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Space Res Assoc, Seabrook, MD USA. RP Weigel, RS (reprint author), Atmospher & Space Phys Lab, Boulder, CO 80303 USA. NR 57 TC 36 Z9 36 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-SPACE JI J. Geophys. Res-Space Phys. PD JUL 23 PY 2003 VL 108 IS A7 AR 1298 DI 10.1029/2002JA009627 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 710UG UT WOS:000184699700001 ER PT J AU Hartmann, MJ Johnson, NJ Towal, RB Assad, C AF Hartmann, MJ Johnson, NJ Towal, RB Assad, C TI Mechanical characteristics of rat vibrissae: Resonant frequencies and damping in isolated whiskers and in the awake behaving animal SO JOURNAL OF NEUROSCIENCE LA English DT Article DE vibrissae; whiskers; rat; tactile; tactual; resonance; vibration; exploratory behavior; exploration; whisking; edge detection ID MYSTACIAL VIBRISSAE; WHISKING; NEOCORTEX; AFFERENTS; MOVEMENT; THALAMUS; MODULUS; KERATIN; CORTEX; UNITS AB We investigated the natural resonance properties and damping characteristics of rat macrovibrissae ( whiskers). Isolated whiskers rigidly fixed at the base showed first-mode resonance peaks between 27 and 260 Hz, principally depending on whisker length. These experimentally measured resonant frequencies were matched using a theoretical model of the whisker as a conical cantilever beam, with Young's modulus as the only free parameter. The best estimate for Young's modulus was similar to 3 - 4 GPa. Results of both vibration and impulse experiments showed that the whiskers are strongly damped, with damping ratios between 0.11 and 0.17. In the behaving animal, whiskers that deflected past an object were observed to resonate but were damped significantly more than isolated whiskers. The time course of damping varied depending on the individual whisker and the phase of the whisking cycle, which suggests that the rat may modulate biomechanical parameters that affect damping. No resonances were observed for whiskers that did not contact the object or during free whisking in air. Finally, whiskers on the same side of the face were sometimes observed to move in opposite directions over the full duration of a whisk. We discuss the potential roles of resonance during natural exploratory behavior and specifically suggest that resonant oscillations may be important in the rat's tactile detection of object boundaries. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Hartmann, MJ (reprint author), CALTECH, Jet Prop Lab, Mail Stop 303-300,4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Hartmann, Mitra/A-8150-2008; Hartmann, Mitra/B-6766-2009 NR 34 TC 113 Z9 114 U1 0 U2 19 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 JUL 23 PY 2003 VL 23 IS 16 BP 6510 EP 6519 PG 10 WC Neurosciences SC Neurosciences & Neurology GA 704DX UT WOS:000184323900014 PM 12878692 ER PT J AU Lombardi, RA Cao, XL Kim, SS Dukor, RK Nafie, LA AF Lombardi, RA Cao, XL Kim, SS Dukor, RK Nafie, LA TI Detection of chirality in solid-state amino acids using Fourier transform vibrational circular dichroism. SO BIOCHEMISTRY LA English DT Meeting Abstract CT 226th National Meeting of the American-Chemical-Society CY SEP 07-11, 2003 CL NEW YORK, NEW YORK SP Amer Chem Soc C1 Syracuse Univ, Dept Chem, Syracuse, NY 13244 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. NR 0 TC 1 Z9 1 U1 0 U2 3 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0006-2960 J9 BIOCHEMISTRY-US JI Biochemistry PD JUL 22 PY 2003 VL 42 IS 28 MA 195 BP 8638 EP 8639 PG 2 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 702XA UT WOS:000184249000220 ER PT J AU Wu, XP Heflin, MB Ivins, ER Argus, DF Webb, FH AF Wu, XP Heflin, MB Ivins, ER Argus, DF Webb, FH TI Large-scale global surface mass variations inferred from GPS measurements of load-induced deformation SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID EARTHS GRAVITY-FIELD; SYSTEM; MOTION AB [1] Detrended crustal deformation measurements from a global network of up to 200 continuous Global Positioning System (GPS) tracking sites are inverted for low degree and order (n, m less than or equal to 6) spherical harmonic series of surface mass variations. An independent geophysical model of the atmosphere, oceans, and water and snow on land is also used to guide the spherical harmonic truncation and to evaluate aliasing errors in the results. Inversion uncertainties decrease significantly as spatial coverage and data quality improve with time, especially in the last few years. Consequently, GPS inverted seasonal geocenter and low degree zonal harmonics converge to those determined by measurements from satellite laser ranging (SLR). Significant n > 1 and non-zonal variations have also been found. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Wu, XP (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 238-600, Pasadena, CA 91109 USA. RI Argus, Donald/F-7704-2011 NR 12 TC 39 Z9 44 U1 0 U2 7 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 JUL 22 PY 2003 VL 30 IS 14 AR 1742 DI 10.1029/2003GL017546 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 709DM UT WOS:000184609500003 ER PT J AU Bleacher, JE Sakimoto, SEH Garvin, JB Wong, M AF Bleacher, JE Sakimoto, SEH Garvin, JB Wong, M TI Deflation/erosion rates for the Parva Member, Dorsa Argentea Formation and implications for the south polar region of Mars SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article DE Mars; polar processes; erosion rates; impact craters; exhumation; pedestal craters ID ORBITER-LASER-ALTIMETER; WIND EROSION; IMPACT CRATERS; SURFACE LAYER; ICE; EVOLUTION; THICKNESS; DEPOSITS AB [1] The origins of the surficial materials in the geologic units surrounding the Martian southern polar region have been poorly constrained on the basis of pre-Mars Global Surveyor (MGS) data and studies. MGS studies suggest that these units are the remnant of volatile loss from an originally massive volatile-rich debris blanket or the result of fluidized slurries resulting from magma/volatile interactions or impact shaking. We use Mars Orbiter Laser Altimeter data to examine a region adjacent to the south polar layered terrain at 72degrees - 79degreesS and 230degrees - 275 degreesE, generally equivalent to the mapped Parva member of the Dorsa Argentea Formation (DAF). The pedestal and "ghost'' impact crater morphologies in this area suggest that extensive deposits of loosely consolidated materials have been removed from this region. The Parva member is thus likely to be the remaining debris blanket from the deflated remnant of an unprotected deposit that was originally similar to the buried DAF deposits in the adjacent Cavi member. Crater counts indicate that the Parva member is of Hesperian age and overlies an older Noachian surface, likely the highland cratered terrain (Npl(1)). If regional deflation began in the Hesperian and continues through today, the region has been exposed to erosion rates of 1.3 - 1.6 x 10(-7) m/yr. However, if deflation started later than the assumed times or ceased in the Amazonian, when deposition of the polar layered deposits began, erosion rates as high as 2. - 5.2 x 10(-7) m/yr might have existed. These erosion rates are within the range of published Martian nonbedrock erosion rates of 10(-8) - 10(-5) m/yr. C1 Franklin & Marshall Coll, Dept Geosci, Lancaster, PA 17604 USA. NASA, Univ Space Res Assoc, Geodynam Branch, Goddard Space Flight Ctr, Greenbelt, MD USA. RP Bleacher, JE (reprint author), Arizona State Univ, Dept Geol Sci, Box 871404, Tempe, AZ 85287 USA. RI Bleacher, Jacob/D-1051-2012 OI Bleacher, Jacob/0000-0002-8499-4828 NR 42 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 JUL 22 PY 2003 VL 108 IS E7 AR 5075 DI 10.1029/2001JE001535 PG 13 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 709FD UT WOS:000184613700001 ER PT J AU Hudait, MK Lin, Y Wilt, DM Wu, F Speck, JS Tivarus, CA Heller, ER Pelz, JP Ringel, SA AF Hudait, MK Lin, Y Wilt, DM Wu, F Speck, JS Tivarus, CA Heller, ER Pelz, JP Ringel, SA TI High-quality InAsyP1-y step-graded buffer by molecular-beam epitaxy (vol 82, pg 3212, 2003) SO APPLIED PHYSICS LETTERS LA English DT Correction C1 Ohio State Univ, Dept Elect Engn, Columbus, OH 43210 USA. NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. Univ Calif Santa Barbara, Dept Mat Sci, Santa Barbara, CA 93106 USA. Ohio State Univ, Dept Phys, Columbus, OH 43210 USA. RP Ringel, SA (reprint author), Ohio State Univ, Dept Elect Engn, Columbus, OH 43210 USA. RI Speck, James/H-5646-2011; Wu, Feng/D-5641-2015 NR 1 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 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD JUL 21 PY 2003 VL 83 IS 3 BP 587 EP 587 DI 10.1063/1.1593822 PG 1 WC Physics, Applied SC Physics GA 701UE UT WOS:000184186700061 ER PT J AU De Troia, G Ade, PAR Bock, JJ Bond, JR Boscaleri, A Contaldi, CR Crill, BP de Bernardis, P Ferreira, PG Giacometti, M Hivon, E Hristov, VV Kunz, M Lange, AE Masi, S Mauskopf, PD Montroy, T Natoli, P Netterfield, CB Pascale, E Piacentini, F Polenta, G Romeo, G Ruhl, JE AF De Troia, G Ade, PAR Bock, JJ Bond, JR Boscaleri, A Contaldi, CR Crill, BP de Bernardis, P Ferreira, PG Giacometti, M Hivon, E Hristov, VV Kunz, M Lange, AE Masi, S Mauskopf, PD Montroy, T Natoli, P Netterfield, CB Pascale, E Piacentini, F Polenta, G Romeo, G Ruhl, JE TI The trispectrum of the cosmic microwave background on subdegree angular scales: an analysis of the BOOMERanG data SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE methods : statistical; cosmic microwave background ID NON-GAUSSIAN STATISTICS; SKY MAPS; POWER SPECTRUM; RADIATION; TESTS AB The trispectrum of the cosmic microwave background can be used to assess the level of non-Gaussianity on cosmological scales. It probes the fourth-order moment, as a function of angular scale, of the probability distribution function of fluctuations and has been shown to be sensitive to primordial non-Gaussianity, secondary anisotropies (such as the Ostriker-Vishniac effect) and systematic effects (such as astrophysical foregrounds). In this paper we develop a formalism for estimating the trispectrum from high-resolution sky maps that incorporates the impact of finite sky coverage. This leads to a series of operations applied to the data set to minimize the effects of contamination due to the Gaussian component and correlations between estimates at different scales. To illustrate the effect of the estimation process, we apply our procedure to the BOOMERanG data set and show that it is consistent with Gaussianity. This work presents the first estimation of the cosmic microwave background trispectrum on subdegree scales. C1 Univ Roma La Sapienza, Dipartimento Fis, I-00185 Rome, Italy. Cardiff Univ, Dept Phys & Astron, Cardiff CF24 3YB, S Glam, Wales. CALTECH, Jet Prop Lab, Pasadena, CA USA. Univ Toronto, Canadian Inst Theoret Astrophys, Toronto, ON M5S 1A1, Canada. CNR, IROE, I-50127 Florence, Italy. Univ Oxford, Oxford OX1 3RH, England. CALTECH, IPAC, Pasadena, CA 91125 USA. Univ Sussex, Ctr Astron, Brighton BN1 9QL, E Sussex, England. Case Western Reserve Univ, Dept Phys, Cleveland, OH 44106 USA. Univ Roma Tor Vergata, Dipartimento Fis, I-00133 Rome, Italy. Univ Toronto, Dept Phys, Toronto, ON, Canada. Univ Toronto, Dept Astron, Toronto, ON, Canada. Ist Nazl Geofis, I-00161 Rome, Italy. RP De Troia, G (reprint author), Univ Roma La Sapienza, Dipartimento Fis, Piazzale Aldo Moro 2, I-00185 Rome, Italy. RI Piacentini, Francesco/E-7234-2010; OI Piacentini, Francesco/0000-0002-5444-9327; 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; Hivon, Eric/0000-0003-1880-2733 NR 38 TC 29 Z9 29 U1 0 U2 0 PU BLACKWELL PUBLISHING LTD PI OXFORD PA 9600 GARSINGTON RD, OXFORD OX4 2DG, OXON, ENGLAND SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD JUL 21 PY 2003 VL 343 IS 1 BP 284 EP 292 DI 10.1046/j.1365-8711.2003.06665.x PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 700JE UT WOS:000184108200030 ER PT J AU Yang, P Wei, HL Kattawar, GW Hu, YX Winker, DM Hostetler, CA Baum, BA AF Yang, P Wei, HL Kattawar, GW Hu, YX Winker, DM Hostetler, CA Baum, BA TI Sensitivity of the backscattering Mueller matrix to particle shape and thermodynamic phase SO APPLIED OPTICS LA English DT Article ID HEXAGONAL ICE CRYSTALS; LIGHT-SCATTERING; MULTIPLE-SCATTERING; SINGLE-SCATTERING; POLARIZATION; CLOUDS; DEPOLARIZATION AB The Mueller matrix (M) corresponding to the phase matrix in the backscattering region (scattering angles ranging from 175degrees to 180degrees) is investigated for light scattering at a 0.532-mum wavelength by hexagonal ice crystals, ice spheres, and water droplets. For hexagonal ice crystals we assume three aspect ratios (plates, compact columns, and columns). It is shown that the contour patterns of the backscattering Mueller matrix elements other than M-11, M-44, M-14, and M-41 depend on particle geometry; M-22 and M-33 are particularly sensitive to the aspect ratio of ice crystals. The Mueller matrix for spherical ice particles is different from those for nonspherical ice particles. In addition to discriminating between spherical and nonspherical particles, the Mueller matrix may offer some insight as to cloud thermodynamic phase. The contour patterns for large ice spheres with an effective size of 100 mum are substantially different from those associated with small water droplets with an effective size of 4 mum. (C) 2003 Optical Society of America. C1 Texas A&M Univ, Dept Atmospher Sci, College Stn, TX 77843 USA. Texas A&M Univ, Dept Phys, College Stn, TX 77843 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Yang, P (reprint author), Texas A&M Univ, Dept Atmospher Sci, TAMU 3150, College Stn, TX 77843 USA. EM pyang@ariel.met.tamu.edu RI Yang, Ping/B-4590-2011; Baum, Bryan/B-7670-2011; Hu, Yongxiang/K-4426-2012 OI Baum, Bryan/0000-0002-7193-2767; NR 26 TC 36 Z9 39 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 JUL 20 PY 2003 VL 42 IS 21 BP 4389 EP 4395 DI 10.1364/AO.42.004389 PG 7 WC Optics SC Optics GA 702YJ UT WOS:000184252300020 PM 12921290 ER PT J AU Boroson, B Vrtilek, SD Kallman, T Corcoran, M AF Boroson, B Vrtilek, SD Kallman, T Corcoran, M TI Chandra grating spectroscopy of the X-ray binary 4U 1700-37 in a flaring state SO ASTROPHYSICAL JOURNAL LA English DT Article DE binaries : close; stars : individual (4U 1700-37); X-rays : binaries; X-rays : individual ( 4U 1700-37) ID QUASI-PERIODIC OSCILLATIONS; STELLAR WIND; VELA X-1; APERIODIC VARIABILITY; LMC X-4; 4U-1700-37; SPECTRUM; LINES; COMPTONIZATION; HERCULES-X-1 AB Chandra X-Ray Observatory grating spectra of the supergiant X-ray binary 4U 1700-37 reveal emission lines from hydrogen- and helium-like S, Si, Mg, and Ne in the 4 - 13 Angstrom range. The spectrum also shows fluorescent lines from S and Si and a prominent Fe Kalpha line at 1.94 Angstrom. The lines contribute to the previously unaccounted "soft excess'' in the flux in this range at orbital phi approximate to 0.7. The X-ray source was observed during intermittent flaring, and the strengths of the lines vary with the source state. The widths of the lines (FWHM approximate to 1000 2000 km s(-1)) can result from either Compton scattering or Doppler shifts. Power spectra of the hard X- rays show red noise, and the soft X- rays and lines show in addition quasi-periodic oscillations and a power spectral break. Helium-like triplets of Si and Mg suggest that the gas is not in a pure photoionization equilibrium. We discuss whether resonant scattering could affect the line ratios or whether a portion of the wind may be heated to temperatures T similar to 10(6) K. C1 MIT, Space Res Ctr, Cambridge, MA 02138 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Boroson, B (reprint author), MIT, Space Res Ctr, Cambridge, MA 02138 USA. NR 61 TC 26 Z9 27 U1 0 U2 1 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 JUL 20 PY 2003 VL 592 IS 1 BP 516 EP 531 DI 10.1086/375636 PN 1 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 700EA UT WOS:000184098600042 ER PT J AU Cliver, EW Ling, AG Richardson, IG AF Cliver, EW Ling, AG Richardson, IG TI Coronal mass ejections, the tail of the solar wind magnetic field distribution, and 11 year cosmic-ray modulation at 1 AU SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmic rays; solar wind; Sun : coronal mass ejections (CMEs) ID PROPAGATING DIFFUSIVE BARRIERS; PIONEER SPACECRAFT MEASUREMENTS; HELIOSPHERIC CURRENT SHEET; OUTER HELIOSPHERE; 1974 MINICYCLE; VOYAGER-2 OBSERVATIONS; GEOMAGNETIC-ACTIVITY; CYCLE VARIATION; INTENSITY; FLUX AB Using a recent classification of the solar wind at 1 AU into its principal components ( slow solar wind, highspeed streams, and coronal mass ejections [CMEs]) for 1972-2000, we show that the monthly averaged Galactic cosmic-ray intensity is anticorrelated with the percentage of time that the Earth is embedded in CME flows. We suggest that this anticorrelation results primarily from a CME-related change in the tail of the distribution function of hourly averaged values of the solar wind magnetic field (B) between solar minimum and solar maximum. The number of high B-values (greater than or equal to10 nT) increases by a factor of similar to3 from minimum to maximum (from 5% of all hours to 17%), with about two-thirds of this increase due to CMEs. On an hour-to-hour basis, average changes of cosmic-ray intensity at Earth become negative for solar wind magnetic field values greater than or equal to10 nT. C1 USAF, Res Lab, Space Vehicles Directorate VSBXS, Hanscom AFB, MA 01731 USA. Radex Inc, Bedford, MA 01730 USA. NASA, Lab High Energy Astrophys Code 661, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Cliver, EW (reprint author), USAF, Res Lab, Space Vehicles Directorate VSBXS, 29 Randolph Rd, Hanscom AFB, MA 01731 USA. OI Richardson, Ian/0000-0002-3855-3634 NR 58 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 JUL 20 PY 2003 VL 592 IS 1 BP 574 EP 579 DI 10.1086/375616 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 700EA UT WOS:000184098600047 ER PT J AU Dominguez, G Westphal, AJ Phillips, MLF Jones, SM AF Dominguez, G Westphal, AJ Phillips, MLF Jones, SM TI A fluorescent aerogel for capture and identification of interplanetary and interstellar dust SO ASTROPHYSICAL JOURNAL LA English DT Article DE astrochemistry; dust, extinction; instrumentation : detectors; interplanetary medium; meteors, meteoroids; techniques : image processing ID PRESOLAR SIC GRAINS; IMPACT; IDPS AB Contemporary interstellar dust has never been analyzed in the laboratory, despite its obvious astronomical importance and its potential as a probe of stellar nucleosynthesis and Galactic chemical evolution. Here we report the discovery of a novel fluorescent aerogel that is capable of capturing hypervelocity dust grains and passively recording their kinetic energies. An array of these "calorimetric" aerogel collectors in low-Earth orbit would lead to the capture and identification of large numbers of interstellar dust grains. C1 Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. Pleasanton Ridge Res Corp, Hayward, CA 94542 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. RP Dominguez, G (reprint author), Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. NR 22 TC 10 Z9 10 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 JUL 20 PY 2003 VL 592 IS 1 BP 631 EP 635 DI 10.1086/375549 PN 1 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 700EA UT WOS:000184098600053 ER PT J AU Brown, TM Ferguson, HC Smith, E Kimble, RA Sweigart, AV Renzini, A Rich, RM VandenBerg, DA AF Brown, TM Ferguson, HC Smith, E Kimble, RA Sweigart, AV Renzini, A Rich, RM VandenBerg, DA TI Evidence of a significant intermediate-age population in the M31 halo from main-sequence photometry SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : evolution; galaxies : halos; galaxies : individual (M31); galaxies : stellar content ID I-BAND OBSERVATIONS; METAL-POOR STARS; HST V-BAND; GLOBULAR-CLUSTERS; METALLICITY DISTRIBUTION; GALAXY; SUBSTRUCTURE; CALIBRATION; DISTANCE; SEARCH AB We present a color-magnitude diagram (CMD) for a minor-axis field in the halo of the Andromeda galaxy (M31), 51' (11 kpc) from the nucleus. These observations, taken with the Advanced Camera for Surveys (ACS) on the Hubble Space Telescope, are the deepest optical images yet obtained, attaining 50% completeness at m(V) = 30.7 mag. The CMD, constructed from similar to3 x 10(5) stars, reaches more than 1.5 mag fainter than the old main-sequence turnoff. Our analysis is based on direct comparisons to ACS observations of four globular clusters through the same filters, as well as chi(2) fitting to a finely spaced grid of calibrated stellar-population models. We find that the M31 halo contains a major (similar to30% by mass) intermediate-age (6-8 Gyr) metal-rich ([Fe/H] > -0.5) population, as well as a significant globular cluster age (11-13.5 Gyr) metal-poor population. These findings support the idea that galaxy mergers played an important role in the formation of the M31 halo. C1 Space Telescope Sci Inst, Baltimore, MD 21218 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. European So Observ, D-85748 Garching, Germany. Univ Calif Los Angeles, Dept Phys & Astron, Div Astron, Los Angeles, CA 90095 USA. Univ Victoria, Dept Phys & Astron, Victoria, BC V8W 3P6, Canada. RP Brown, TM (reprint author), Space Telescope Sci Inst, 3700 San Martin Dr, Baltimore, MD 21218 USA. NR 32 TC 121 Z9 121 U1 0 U2 1 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 JUL 20 PY 2003 VL 592 IS 1 BP L17 EP L20 DI 10.1086/376935 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 700ED UT WOS:000184098900005 ER PT J AU Olbert, CM Keohane, JW Arnaud, KA Dyer, KK Reynolds, SP Safi-Harb, S AF Olbert, CM Keohane, JW Arnaud, KA Dyer, KK Reynolds, SP Safi-Harb, S TI Chandra detection of a pulsar wind nebula associated with supernova remnant 3C 396 SO ASTROPHYSICAL JOURNAL LA English DT Article DE ISM : individual (G39.2-0.3); pulsars : general; stars : neutron; supernova remnants ID GAMMA-RAY REPEATERS; X-RAY; G39.2-0.3; RADIO AB We present a 100 ks observation of the Galactic supernova remnant 3C 396 (G39.2-0.3) with the Chandra X-Ray Observatory that we compare with a 20 cm map of the remnant from the Very Large Array. In the Chandra images, a nonthermal nebula containing an embedded pointlike source is apparent near the center of the remnant that we interpret as a synchrotron pulsar wind nebula surrounding a yet undetected pulsar. From the 2-10 keV spectrum for the nebula [N-H = (5.3 +/- 0.9) x 10(22) cm(-2), Gamma = 1.5 +/- 0.3] we derive an unabsorbed X-ray flux of S-X = 1.62 x 10(-12) ergs cm(-2) s(-1), and from this we estimate the spin-down power of the neutron star to be (E)over dot = 7.2 x 10(36) ergs s(-1). The central nebula is morphologically complex, showing bent, extended structure. The radio and X- ray shells of the remnant correlate poorly on large scales, particularly on the eastern half of the remnant, which appears very faint in X-ray images. At both radio and X-ray wavelengths, the western half of the remnant is substantially brighter than the eastern half. C1 N Carolina Sch Sci & Math, Durham, NC 27705 USA. Univ N Carolina, Dept Phys & Astron, Chapel Hill, NC 27599 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Natl Radio Astron Observ, Socorro, NM 87801 USA. N Carolina State Univ, Raleigh, NC 27695 USA. Univ Manitoba, Winnipeg, MB R3T 2N2, Canada. RP Olbert, CM (reprint author), N Carolina Sch Sci & Math, 1219 Broad St, Durham, NC 27705 USA. NR 21 TC 17 Z9 17 U1 0 U2 1 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 JUL 20 PY 2003 VL 592 IS 1 BP L45 EP L48 DI 10.1086/377348 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 700ED UT WOS:000184098900012 ER PT J AU Acikmese, A Corless, M AF Acikmese, A Corless, M TI Robust tracking and disturbance rejection of bounded rate signals for uncertain/non-linear systems SO INTERNATIONAL JOURNAL OF CONTROL LA English DT Article ID INVARIANT MULTIVARIABLE SYSTEMS; NONLINEAR-SYSTEMS; OUTPUT-FEEDBACK AB We consider the problem of designing controllers for non-linear/uncertain systems to achieve tracking of a reference output signal in the presence of a disturbance input signal. When the exogenous signal (combined reference and disturbance) is constant, we require that the tracking error eventually go to zero. When the exogenous signal has a bounded rate, we require that the tracking error be eventually bounded with a bound which only depends on the bound on the magnitude of the rate of the exogenous signal. We also require that the state and control input are bounded when the exogenous signal is bounded. We propose controllers which have a classical PI (proportional integral) structure using state feedback. For linear systems and specific classes of non-linear/uncertain systems we present conditions whose satisfaction guarantees the existence of controllers which achieve the desired behaviour. Satisfaction of these conditions also yields the controller gain matrices. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Purdue Univ, Sch Aeronaut & Astronaut, W Lafayette, IN 47907 USA. RP Acikmese, A (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Corless, Martin/F-2299-2011 NR 19 TC 3 Z9 3 U1 0 U2 3 PU TAYLOR & FRANCIS LTD PI ABINGDON PA 4 PARK SQUARE, MILTON PARK, ABINGDON OX14 4RN, OXON, ENGLAND SN 0020-7179 J9 INT J CONTROL JI Int. J. Control PD JUL 20 PY 2003 VL 76 IS 11 BP 1129 EP 1141 DI 10.1080/0020717031000124156 PG 13 WC Automation & Control Systems SC Automation & Control Systems GA 696YE UT WOS:000183914500010 ER PT J AU Steve, BA Levy, D AF Steve, BA Levy, D TI High-order semi-discrete central-upwind schemes for multi-dimensional Hamilton-Jacobi equations SO JOURNAL OF COMPUTATIONAL PHYSICS LA English DT Article DE Hamilton-Jacobi equations; central schemes; semi-discrete schemes; high order; WENO; CWENO; monotone fluxes ID ESSENTIALLY NONOSCILLATORY SCHEMES; CONVECTION-DIFFUSION EQUATIONS; HYPERBOLIC CONSERVATION-LAWS; WEIGHTED ENO SCHEMES; CENTRAL WENO SCHEMES; VISCOSITY SOLUTIONS; SYSTEMS; DISCRETIZATION AB We present the first fifth-order, semi-discrete central-upwind method for approximating solutions of multi-dimensional Hamilton-Jacobi equations. Unlike most of the commonly used high-order upwind schemes, our scheme is formulated as a Godunov-type scheme. The scheme is based on the fluxes of Kurganov-Tadmor and Kurganov-Noelle-Petrova, and is derived for an arbitrary number of space dimensions. A theorem establishing the monotonicity of these fluxes is provided. The spatial discretization is based on a weighted essentially non-oscillatory reconstruction of the derivative. The accuracy and stability properties of our scheme are demonstrated in a variety of examples. A comparison between our method and other fifth-order schemes for Hamilton-Jacobi equations shows that our method exhibits smaller errors without any increase in the complexity of the computations. (C) 2003 Elsevier Science B.V. All rights reserved. C1 Stanford Univ, Dept Math, Stanford, CA 94305 USA. Stanford Univ, Program Sci Comp & Comp ath, Moffett Field, CA 94035 USA. NASA, Ames Res Ctr, Adv Supercomp Div, Moffett Field, CA 94035 USA. RP Levy, D (reprint author), Stanford Univ, Dept Math, Stanford, CA 94305 USA. NR 30 TC 26 Z9 29 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 0021-9991 J9 J COMPUT PHYS JI J. Comput. Phys. PD JUL 20 PY 2003 VL 189 IS 1 BP 63 EP 87 DI 10.1016/S0021-9991(03)00201-8 PG 25 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA 703TK UT WOS:000184296900004 ER PT J AU Yu, JY Lui, WT AF Yu, JY Lui, WT TI A linear relationship between ENSO intensity and tropical instability wave activity in the eastern Pacific Ocean SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID SEA-SURFACE TEMPERATURE; EQUATORIAL PACIFIC AB The interannual variations of tropical instability waves (TIWs) in the eastern Pacific Ocean and their relationships with ENSO intensity are studied using a 28-year long coupled atmosphere-ocean general circulation model (CGCM) simulation. The activity of TIWs is measured by the root-mean-square value of the 50-day high-pass filtered sea surface temperature (SST) perturbations produced in the simulation. The CGCM realistically produces two branches of large TIW activity near the equator: one at 2 degrees N and the other at 2 degrees S. It is found that along both branches there are linear relationships between the year-to-year variations of TIW activity and those of ENSO intensity. TIW activity is enhanced or reduced in proportion to the NINO3 SST anomalies, with larger activity in La Nina years and smaller activity in El Nino years. It is found that ENSO modulates TIW activity in both branches primarily by changing the latitudinal SST gradient associated with the SST front immediately north of the equator. Weaker correlations are found between the year-to-year variations of TIW activity and those of the ocean current shears between the south equatorial current and the equatorial undercurrent or the north equatorial countercurrent. This CGCM study suggests that the baroclinic instability associated with the northern SST front is a major generation mechanism for both the northern and southern TIW branches in the eastern Pacific Ocean. C1 Univ Calif Irvine, Dept Earth Syst Sci, Irvine, CA USA. CALTECH, Jet Prop Lab, Pasadena, CA USA. RP Yu, JY (reprint author), Univ Calif Irvine, Dept Earth Syst Sci, Irvine, CA USA. EM jyyu@uci.edu; lui@pacific.jpl.nasa.gov RI Yu, Jin-Yi/G-3413-2011 OI Yu, Jin-Yi/0000-0001-6156-7623 NR 15 TC 38 Z9 42 U1 2 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 JUL 19 PY 2003 VL 30 IS 14 AR 1735 DI 10.1029/2003GL017176 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 708ZJ UT WOS:000184600000002 ER PT J AU Christopher, SA Wang, J Ji, Q Tsay, SC AF Christopher, SA Wang, J Ji, Q Tsay, SC TI Estimation of diurnal shortwave dust aerosol radiative forcing during PRIDE SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE dust aerosols; diurnal forcing; dust optical properties; forcing uncertainties; flux calculation and comparison ID BIOMASS BURNING AEROSOLS; SAHARAN DUST; MINERAL DUST; OPTICAL-PROPERTIES; GOES-8 IMAGER; SURFACE; IRRADIANCE; SATELLITE; ABSORPTION; THICKNESS AB [1] Using measured and derived aerosol properties from the Puerto Rico Dust Experiment (PRIDE), a four-stream broadband radiative transfer model is used to calculate the downward shortwave irradiance (DSWI) at the surface and the shortwave irradiance at the top of atmosphere (TOA). The results of the calculated DSWI are compared against pyranometer measurements from the Surface Measurements For Atmospheric Radiative Transfer (SMART) instrument suite at Roosevelt Road (18.20degreesN, 65.60degreesW). Using aerosol optical thickness retrievals from half-hourly geostationary satellite data (GOES 8 imager), the diurnal short wave aerosol forcing (SWARF) of dust aerosols both at the surface and TOA are calculated for the entire study area (14degreesN similar to26degreesN, 61degreesW similar to 73degreesW). For selected days, the Clouds and the Earth Radiant Energy System (CERES) TOA shortwave irradiance values from Terra are compared with radiative transfer calculations. Wang et al. [2003] show that the satellite derived aerosol optical thickness is in excellent agreement with Aerosol Robotic Network (AERONET) values. Results of this study show that the calculated direct, diffuse and total DSWI are in excellent agreement with the corresponding SMART values with biases of 1.8%, -3.3% and 0.5% respectively, indicating that dust aerosols are well characterized in the radiative transfer model. This is well within the measured uncertainties (1.3%) and the model uncertainties (5%). The monthly mean value and standard deviation of aerosol optical thickness at 670 nm (AOT670) during PRIDE are 0.26 +/- 0.13, and the corresponding monthly mean daytime SWARF values are -12.34 +/- 9.62 W m(-2) at TOA and -18.13 +/- 15.81 W m(-2) at the surface, respectively. Our results also show that if diurnal changes in aerosol optical thickness are not considered, it leads to uncertainties in SWARF of 4 W m(-2) at the surface and 2 W m(-2) at the TOA. The CERES TOA short wave irradiance underestimates calculated values by about 10 W m(-2) mainly due problems in misclassification of aerosols and lack of aerosol angular dependence models (ADMs) in the current CERES algorithms. This study is among the first to demonstrate the potential of the GOES 8 imagers in retrieving aerosol optical thickness and estimating the daytime diurnal SWARF of dust, both at the TOA and surface, in low to moderate dust loading regions over the oceans. C1 Univ Alabama, Dept Atmospher Sci, Huntsville, AL 35805 USA. NASA, Goddard Space Flight Ctr, SSAI, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. RP Christopher, SA (reprint author), Univ Alabama, Dept Atmospher Sci, Huntsville, AL 35805 USA. EM sundar@nsstc.uah.edu; wangjun@nsstc.uah.edu; ji@climate.gsfc.nasa.gov; tsay@climate.gsfc.nasa.gov RI Christopher, Sundar/E-6781-2011; Tsay, Si-Chee/J-1147-2014; Wang, Jun/A-2977-2008 OI Wang, Jun/0000-0002-7334-0490 NR 66 TC 43 Z9 43 U1 0 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 JUL 19 PY 2003 VL 108 IS D19 AR 8596 DI 10.1029/2002JD002787 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 709BR UT WOS:000184605300001 ER PT J AU Haywood, J Francis, P Osborne, S Glew, M Loeb, N Highwood, E Tanre, D Myhre, G Formenti, P Hirst, E AF Haywood, J Francis, P Osborne, S Glew, M Loeb, N Highwood, E Tanre, D Myhre, G Formenti, P Hirst, E TI Radiative properties and direct radiative effect of Saharan dust measured by the C-130 aircraft during SHADE: 1. Solar spectrum SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE aerosols; Saharan dust; radiative forcing; radiation balance; mineral dust; aircraft measurements ID AEROSOL OPTICAL-PROPERTIES; SKY RADIANCE MEASUREMENTS; ENERGY SYSTEM CERES; MINERAL AEROSOLS; SAFARI 2000; SATELLITE; MODEL; CLOUDS; SUN; DISTRIBUTIONS AB [1] The physical and optical properties of Saharan dust aerosol measured by the Met Office C-130 during the Saharan Dust Experiment (SHADE) are presented. Additional radiation measurements enable the determination of the aerosol optical depth, tau(aerlambda), and the direct radiative effect (DRE) of the mineral dust. The results suggest that the absorption by Saharan dust is significantly overestimated in the solar spectrum if standard refractive indices are used. Our measurements suggest an imaginary part of the refractive index of 0.0015i is appropriate at a wavelength lambda of 0.55 mum. Different methods for determining tau(aerlambda=0.55) are presented, and the accuracy of each retrieval method is assessed. The value tau(aerlambda=0.55) is estimated as 1.48 +/- 0.05 during the period of heaviest dust loading, which is derived from an instantaneous DRE of approximately -129 +/- 5 Wm(-2) or an enhancement of the local planetary albedo over ocean of a factor of 2.7 +/- 0.1. A comparison of the DRE derived from the C-130 instrumentation and from the Clouds and the Earth's Radiant Energy System (CERES) instrument on the Tropical Rainfall Measuring Mission (TRMM) satellite is presented; the results generally showing agreement to within a factor of 1.2. The results suggest that Saharan dust aerosol exerts the largest local and global DRE of all aerosol species and should be considered explicitly in global radiation budget studies. C1 DERA, Met Off, Farnborough GU14 0LX, Hants, England. NASA, Langley Res Ctr, Hampton, VA 23665 USA. Univ Reading, Dept Meteorol, Reading, Berks, England. Univ Sci & Tech Lille Flandres Artois, CNRS, Opt Atmospher Lab, Lille, France. Univ Oslo, Dept Geophys, Oslo, Norway. Max Planck Inst Chem, D-55128 Mainz, Germany. Univ Hertfordshire, Sci & Technol Res Ctr, Hatfield, Herts, England. RP Haywood, J (reprint author), DERA, Met Off, Y46 Bldg, Farnborough GU14 0LX, Hants, England. EM jim.haywood@metoffice.com; pete.francis@metoffice.com; simon.osborne@metoffice.com; glew@metoffice.com; n.g.loeb@larc.nasa.gov; E.J.Highwood@met.rdg.ac.uk; tanre@loa.univ-lille1.fr; gunnar.myhre@geofysikk.uio.no; formenti@lisa.univ-paris12.fr; E.Hirst@herts.ac.uk RI Myhre, Gunnar/A-3598-2008; Highwood, Ellie/A-2402-2013; Francis, Peter/H-9352-2013 OI Myhre, Gunnar/0000-0002-4309-476X; Francis, Peter/0000-0002-5869-803X NR 39 TC 205 Z9 206 U1 2 U2 20 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 JUL 18 PY 2003 VL 108 IS D18 AR 8577 DI 10.1029/2002JD002687 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 709BL UT WOS:000184604800001 ER PT J AU Kent, GS Trepte, CR Wang, PH Lucker, PL AF Kent, GS Trepte, CR Wang, PH Lucker, PL TI Problems in separating aerosol and cloud in the Stratospheric Aerosol and Gas Experiment (SAGE) II data set under conditions of lofted dust: Application to the Asian deserts SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID ATMOSPHERIC AEROSOL; OCCULTATION DATA; MINERAL AEROSOL; NORTH-ATLANTIC; PACIFIC; STORMS; MODEL; OCEAN AB [1] Stratospheric Aerosol and Gas Experiment II aerosol data obtained at two wavelengths, 525 nm and 1020 nm, have been used for some time to identify the presence of cloud along the optical path from the Sun to the satellite instrument. Examination of data obtained over desert regions in the Northern Hemisphere, particularly the Taklimakan Desert, indicates that this separation method does not always operate correctly. In regions where there is expected to be a large amount of lofted dust, unexpectedly low values of mean extinction are found, combined with higher than expected amounts of cloud. These anomalous data have been analyzed in detail, and the discrepancy is plausibly shown to be due to faulty identification of lofted dust as cloud. Six Northern Hemisphere desert regions, together with three comparison regions, have been identified for study and the anomalies used to develop a description of the seasonal and altitudinal characteristics of the lofted aerosol over these regions. C1 Sci & Technol Corp, Hampton, VA 23666 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Kent, GS (reprint author), Sci & Technol Corp, 101 Res Dr, Hampton, VA 23666 USA. EM g.s.kent@larc.nasa.gov NR 22 TC 5 Z9 5 U1 0 U2 3 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 JUL 18 PY 2003 VL 108 IS D14 AR 4410 DI 10.1029/2002JD002412 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 709AX UT WOS:000184603500001 ER PT J AU Gruener, JE Ming, DW Henderson, KE Galindo, C AF Gruener, JE Ming, DW Henderson, KE Galindo, C TI Common ion effects in zeoponic substrates: wheat plant growth experiment SO MICROPOROUS AND MESOPOROUS MATERIALS LA English DT Article; Proceedings Paper CT 6th International Conference on Occurence, Properties and Utilization of Natural Zeolites CY JUN 03-07, 2002 CL ARISTOTLE UNIV, THESSALONIKI, GREECE SP Int Comm Nat Zeolites, Hellenic Inst Geol & Mineral Explorat HO ARISTOTLE UNIV DE zeolite; zeoponics; clinoptilolite; apatite; wheat ID PHOSPHATE ROCK; CLINOPTILOLITE; MIXTURES; SOILS AB The National Aeronautics and Space Administration (NASA) is developing a zeolite-based synthetic substrate, termed zeoponics. The zeoponic substrate, consisting of NH4+- and K+-exchanged clinoptilolite, and a synthetic apatite, provides all of the plant-essential nutrients through mineral dissolution and ion exchange, with only the addition of water. Initial experiments with wheat resulted in good vegetative growth, however, a subsequent experiment grown to maturity resulted in poor seed yield. Plant-tissue analyses suggested that high P and low Ca concentrations were possible reasons for the low yield. To address the nutrient imbalances, the Ca-bearing minerals dolomite, wollastonite, and calcite were examined as amendments to the zeoponic substrate to provide a common ion effect (i.e., Ca increases in solution from the dissolution of the Ca-bearing minerals will reduce the dissolution of the synthetic apatite, and thus reduce the amount of P available for plant uptake). Plant tissue Ca for all wheat plants grown in amended zeoponic substrates increased with increasing mineral solubilities of the added Ca-bearing minerals, while plant tissue P decreased with increasing mineral solubilities of the added Ca-bearing minerals. Wheat plants grown with the calcite amendment had the highest Ca concentrations (i.e., 0.45 wt.%) and the lowest P concentrations (i.e., 0.76 wt.%). Seed yield and harvest index were also highest of the plants grown in zeoponic substrate when calcite was the amendment (i.e., 1.57 g/plant and 45.7, respectively). This data illustrates that Ca-bearing minerals do provide a common ion effect in zeoponic substrates. (C) 2003 Elsevier Inc. All rights reserved. C1 Hernandez Engn Inc, Houston, TX 77062 USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Gruener, JE (reprint author), Hernandez Engn Inc, 16055 Space Ctr Blvd,Suite 725, Houston, TX 77062 USA. NR 17 TC 11 Z9 11 U1 2 U2 7 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1387-1811 J9 MICROPOR MESOPOR MAT JI Microporous Mesoporous Mat. PD JUL 18 PY 2003 VL 61 IS 1-3 BP 223 EP 230 DI 10.1016/S1387-1811(03)00371-8 PG 8 WC Chemistry, Applied; Chemistry, Physical; Nanoscience & Nanotechnology; Materials Science, Multidisciplinary SC Chemistry; Science & Technology - Other Topics; Materials Science GA 704DY UT WOS:000184324100022 ER PT J AU Beiersdorfer, RE Ming, DW Galindo, C AF Beiersdorfer, RE Ming, DW Galindo, C TI Solubility and cation exchange properties of zeoponic substrates SO MICROPOROUS AND MESOPOROUS MATERIALS LA English DT Article; Proceedings Paper CT 6th International Conference on Occurence, Properties and Utilization of Natural Zeolites CY JUN 03-07, 2002 CL ARISTOTLE UNIV, THESSALONIKI, GREECE SP Int Comm Nat Zeolites, Hellenic Inst Geol & Mineral Explorat HO ARISTOTLE UNIV DE bioregenerative life support; clinoptilolite; common-ion effect; hydroxyapatite; zeolite; zeoponics ID PHOSPHATE ROCK; CLINOPTILOLITE; SYSTEMS; 25-DEGREES-C; WOLLASTONITE; NOMENCLATURE; DISSOLUTION; PHOSPHORUS; ZEOLITES; MIXTURES AB A zeoponic plant growth system is defined as the cultivation of plants in artificial soils, which have zeolites as a major component. Batch-equilibrium studies of zeoponic substrates indicate that the nutrients NH4-N (19.7-73.6 mg dm(-3)), P (0.57-14.99 mgdm(-3)), K (14.8-104.9 mg dm(-3)), and Mg (0.11-6.68 mg dm(-3)) are available to plants at sufficient levels. Solution Ca concentrations (0.47-3.40 mg dm(-3)) are less than optimal. Solution concentrations of NH4+, K+, Ca2+, and Mg2+ all decreased with increasing clinoptilolite to hydroxyapatite ratio in the sample. Solution concentrations of phosphorus initially increased, reached a maximum value and then decreased with increasing clinoptilolite to hydroxyapatite ratio in the sample, The NH4+-exchanged clinoptilolite is more efficient in dissolving synthetic hydroxy-apatite than the K+-exchanged clinoptilolite. The addition of calcite, dolomite or wollastonite to the zeoponic substrate resulted in an exponential decrease in solution P concentrations (from 15.05 to 1.49 mg dm(-3)). The exponential rate of decay was greatest for calcite (5.60 wt.%(-1)), intermediate for wollastonite (2.85 wt.%(-1)) and least for dolomite (1.58 wt.%(-1)). Additions of the three minerals resulted in linear increases in the solution Ca concentrations (from 0.51 to 2.47 mg dm(-3)). The rate of increase was greatest for calcite (3.64 mg dm(-3) wt.%(-1)), intermediate for wollastonite (2.41 mg dm(-3) wt.%(-1)) and least for dolomite (0.61 mg dm(-3) wt.%(-1)). The observed changes in solution P and Ca concentrations are consistent with the solubilities of calcite, dolomite and wollastonite and with expected changes due to a common ion effect with Ca. Published by Elsevier Inc. C1 Youngstown State Univ, Dept Geol & Environm Sci, Youngstown, OH 44555 USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. Hernandez Engn Inc, Houston, TX 77062 USA. RP Beiersdorfer, RE (reprint author), Youngstown State Univ, Dept Geol & Environm Sci, Youngstown, OH 44555 USA. NR 53 TC 7 Z9 7 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1387-1811 J9 MICROPOR MESOPOR MAT JI Microporous Mesoporous Mat. PD JUL 18 PY 2003 VL 61 IS 1-3 BP 231 EP 247 DI 10.1016/S1387-1811(03)00372-X PG 17 WC Chemistry, Applied; Chemistry, Physical; Nanoscience & Nanotechnology; Materials Science, Multidisciplinary SC Chemistry; Science & Technology - Other Topics; Materials Science GA 704DY UT WOS:000184324100023 ER PT J AU Gomez-Gutierrez, J Peterson, WT De Robertis, A Brodeur, RD AF Gomez-Gutierrez, J Peterson, WT De Robertis, A Brodeur, RD TI Mass mortality of krill caused by parasitoid ciliates SO SCIENCE LA English DT Article ID EUPHAUSIID THYSANOESSA-INERMIS C1 Ctr Interdisciplinario Ciencias Marinas, La Paz 23096, BCS, Mexico. Oregon State Univ, Coll Ocean & Atmospher Sci, Corvallis, OR 97331 USA. Natl Marine Fisheries Serv, Natl Ocean & Atmospher Adm, NW Fisheries Sci Ctr, Newport, OR 97365 USA. RP Gomez-Gutierrez, J (reprint author), Ctr Interdisciplinario Ciencias Marinas, La Paz 23096, BCS, Mexico. NR 5 TC 45 Z9 49 U1 2 U2 4 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD JUL 18 PY 2003 VL 301 IS 5631 BP 339 EP 339 DI 10.1126/science.1085164 PG 1 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 702CG UT WOS:000184207300034 PM 12869754 ER PT J AU Rudnick, DL Boyd, TJ Brainard, RE Carter, GS Egbert, GD Gregg, MC Holloway, PE Klymak, JM Kunze, E Lee, CM Levine, MD Luther, DS Martin, JP Merrifield, MA Moum, JN Nash, JD Pinkel, R Rainville, L Sanford, TB AF Rudnick, DL Boyd, TJ Brainard, RE Carter, GS Egbert, GD Gregg, MC Holloway, PE Klymak, JM Kunze, E Lee, CM Levine, MD Luther, DS Martin, JP Merrifield, MA Moum, JN Nash, JD Pinkel, R Rainville, L Sanford, TB TI From tides to mixing along the Hawaiian ridge SO SCIENCE LA English DT Article ID INTERNAL TIDES; ABYSSAL OCEAN; DEEP-OCEAN; DISSIPATION; SEAMOUNT AB The cascade from tides to turbulence has been hypothesized to serve as a major energy pathway for ocean mixing. We investigated this cascade along the Hawaiian Ridge using observations and numerical models. A divergence of internal tidal energy flux observed at the ridge agrees with the predictions of internal tide models. Large internal tidal waves with peak-to-peak amplitudes of up to 300 meters occur on the ridge. Internal-wave energy is enhanced, and turbulent dissipation in the region near the ridge is 10 times larger than open-ocean values. Given these major elements in the tides-to-turbulence cascade, an energy budget approaches closure. C1 Univ Calif San Diego, Scripps Inst Oceanog, La Jolla, CA 92093 USA. Oregon State Univ, Coll Ocean & Atmospher Sci, Corvallis, OR 97331 USA. NOAA, Natl Marine Fisheries Serv, Pacific Isl Fisheries Sci Ctr, Honolulu Lab, Honolulu, HI 96822 USA. Univ Washington, Appl Phys Lab, Seattle, WA 98105 USA. Univ New S Wales, Sch Geog & Oceanog, Canberra, ACT 2600, Australia. Univ Hawaii, Dept Oceanog, Honolulu, HI 96822 USA. RP Rudnick, DL (reprint author), Univ Calif San Diego, Scripps Inst Oceanog, La Jolla, CA 92093 USA. RI Klymak, Jody/A-3041-2008; Moum, James/A-1880-2012; Rudnick, Daniel/J-8948-2016; OI Klymak, Jody/0000-0003-4612-8600; Rudnick, Daniel/0000-0002-2624-7074; Egbert, Gary/0000-0003-1276-8538 NR 24 TC 188 Z9 191 U1 4 U2 48 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD JUL 18 PY 2003 VL 301 IS 5631 BP 355 EP 357 DI 10.1126/science.1085837 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 702CG UT WOS:000184207300040 PM 12869758 ER PT J AU Schroder, T Leroy, S Stendel, M Kaas, E AF Schroder, T Leroy, S Stendel, M Kaas, E TI Validating the microwave sounding unit stratospheric record using GPS occultation SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID TEMPERATURE TIME-SERIES; RADIO OCCULTATION; ATMOSPHERE; TRENDS AB [1] We validate the temperature climatology recorded by the Microwave Sounding Unit with GPS occultation data collected by the GPS/MET experiment. We choose to validate only the lower stratospheric MSU climatology in order to circumvent the wet-dry ambiguity associated with GPS occultation in the mid- to lower troposphere. We simulate the lower stratospheric channel's brightness temperature by convolving each GPS/MET temperature profile with a vertical weighting function and then map the irregularly gridded data using a Bayesian interpolation scheme. In northern polar night, the MSU T-ls deviates from GPS occultation by as much as 10 K while occultation is consistent with the NCEP Reanalysis used for diagnostic purposes. NCEP and GPS occultation deviate by 1 K in the tropics, consistent with a warm bias in NCEP Reanalysis. GPS occultation renders the problems MSU encounters with inter-satellite calibration obsolete, because calibration by atomic clocks is free of systematic error and can completely cover the diurnal cycle. C1 Danish Meteorol Inst, Div Res, DK-2100 Copenhagen, Denmark. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Schroder, T (reprint author), CALTECH, Div Geol & Planetary Sci, Pasadena, CA 91125 USA. RI Stendel, Martin/E-8499-2010; Kaas, Eigil/M-2590-2014 OI Kaas, Eigil/0000-0001-6970-2404 NR 22 TC 19 Z9 19 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 JUL 17 PY 2003 VL 30 IS 14 AR 1734 DI 10.1029/2003GL017588 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 708ZC UT WOS:000184599400004 ER PT J AU Bais, AF Madronich, S Crawford, J Hall, SR Mayer, B van Weele, M Lenoble, J Calvert, JG Cantrell, CA Shetter, RE Hofzumahaus, A Koepke, P Monks, PS Frost, G McKenzie, R Krotkov, N Kylling, A Swartz, WH Lloyd, S Pfister, G Martin, TJ Roeth, EP Griffioen, E Ruggaber, A Krol, M Kraus, A Edwards, GD Mueller, M Lefer, BL Johnston, P Schwander, H Flittner, D Gardiner, BG Barrick, J Schmitt, R AF Bais, AF Madronich, S Crawford, J Hall, SR Mayer, B van Weele, M Lenoble, J Calvert, JG Cantrell, CA Shetter, RE Hofzumahaus, A Koepke, P Monks, PS Frost, G McKenzie, R Krotkov, N Kylling, A Swartz, WH Lloyd, S Pfister, G Martin, TJ Roeth, EP Griffioen, E Ruggaber, A Krol, M Kraus, A Edwards, GD Mueller, M Lefer, BL Johnston, P Schwander, H Flittner, D Gardiner, BG Barrick, J Schmitt, R TI International Photolysis Frequency Measurement and Model Intercomparison (IPMMI): Spectral actinic solar flux measurements and modeling SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE actinic flux; solar ultraviolet radiation; UV modeling; UV spectral measurements; model intercomparison ID ABSORPTION CROSS-SECTIONS; MULTIPLE-SCATTERING; RADIATION-FIELD; SPHERICAL MODEL; UV MEASUREMENTS; SPECTRORADIOMETRY; OZONE; TROPOSPHERE; IRRADIANCE; ATMOSPHERE AB [1] The International Photolysis Frequency Measurement and Model Intercomparison (IPMMI) took place in Boulder, Colorado, from 15 to 19 June 1998, aiming to investigate the level of accuracy of photolysis frequency and spectral downwelling actinic flux measurements and to explore the ability of radiative transfer models to reproduce the measurements. During this period, 2 days were selected to compare model calculations with measurements, one cloud-free and one cloudy. A series of ancillary measurements were also performed and provided parameters required as input to the models. Both measurements and modeling were blind, in the sense that no exchanges of data or calculations were allowed among the participants, and the results were objectively analyzed and compared by two independent referees. The objective of this paper is, first, to present the results of comparisons made between measured and modeled downwelling actinic flux and irradiance spectra and, second, to investigate the reasons for which some of the models or measurements deviate from the others. For clear skies the relative agreement between the 16 models depends strongly on solar zenith angle (SZA) and wavelength as well as on the input parameters used, like the extraterrestrial (ET) solar flux and the absorption cross sections. The majority of the models (11) agreed to within about +/-6% for solar zenith angles smaller than similar to60degrees. The agreement among the measured spectra depends on the optical characteristics of the instruments (e.g., slit function, stray light rejection, and sensitivity). After transforming the measurements to a common spectral resolution, two of the three participating spectroradiometers agree to within similar to10% for wavelengths longer than 310 nm and at all solar zenith angles, while their differences increase when moving to shorter wavelengths. Most models agree well with the measurements (both downwelling actinic flux and global irradiance), especially at local noon, where the agreement is within a few percent. A few models exhibit significant deviations with respect either to wavelength or to solar zenith angle. Models that use the Atmospheric Laboratory for Applications and Science 3 (ATLAS-3) solar flux agree better with the measured spectra, suggesting that ATLAS-3 is probably more appropriate for radiative transfer modeling in the ultraviolet. C1 Aristotle Univ Thessaloniki, Lab Atmospher Phys, GR-54006 Thessaloniki, Greece. Natl Ctr Atmospher Res, Div Atmospher Chem, Boulder, CO 80303 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. Royal Netherlands Meteorol Inst, NL-3730 AE De Bilt, Netherlands. Univ Grenoble 1, Equipe Interact Rayonnement Solaire Atmosphere, F-38000 Grenoble, France. Univ Sci & Technol Lille, Opt Atmospher Lab, Lille, France. Forschungszentrum Julich, Inst Chem & Dynam Geosphaere Troposphaere 2, D-52425 Julich, Germany. Univ Munich, Inst Meteorol, D-80333 Munich, Germany. Univ Leicester, Dept Chem, Leicester LE1 7RH, Leics, England. NOAA, Aeron Lab, Boulder, CO 80303 USA. Natl Inst Water & Atmospher Res, Lauder 50061, New Zealand. Univ Maryland Baltimore Cty, Goddard Earth Sci & Technol Ctr, Baltimore, MD 21250 USA. Norwegian Inst Air Res, N-2027 Kjeller, Norway. Johns Hopkins Univ, Appl Phys Lab, Laurel, MD 20723 USA. Karl Franzens Univ Graz, Inst Geophys Astrophys & Meteorol, A-8010 Graz, Austria. Fraunhofer Inst Atmosphar Umweltforsch, Garmisch Partenkirchen, Germany. York Univ, Dept Earth & Atmospher Sci, N York, ON M3J 1P3, Canada. Univ Munich, Inst Meteorol, D-80333 Munich, Germany. Inst Marine & Atmospher Res, NL-3508 TA Utrecht, Netherlands. Forschungszentrum Julich, Inst Atmosphaer Chem, Julich, Germany. Univ Arizona, Inst Atmospher Phys, Tucson, AZ 85721 USA. British Antarctic Survey, Cambridge CB3 0ET, England. Meteorol Consult GmbH, D-61479 Glashutten, Germany. RP Bais, AF (reprint author), Aristotle Univ Thessaloniki, Lab Atmospher Phys, GR-54006 Thessaloniki, Greece. EM abais@auth.gr; sasha@acd.ucar.edu; j.h.crawford@larc.nasa.gov; halls@ucar.edu; bernhard.mayer@dlr.de; weelevm@knmi.nl; jacqueline.lenoble@ujf-grenoble.fr; calvert@acd.ucar.edu; cantrell@ncar.ucar.edu; a.hofzumahaus@fz-juelich.de; peter.koepke@lrz.uni-muenchen.de; p.s.monks@le.ac.uk; gfrost@al.noaa.gov; r.mckenzie@niwa.co.nz; krotkov@chescat.gsfc.nasa.gov; arve.kylling@nilu.no; bill.swartz@jhuapl.edu; Steven.Lloyd@jhuapl.edu; pfister@ucar.edu; timothy.martin@gmx.de; e.p.roeth@fz-juelich.de; erik@nimbus.yorku.ca; krol@phys.uu.nl; gde@acd.ucar.edu; JO1@gmx.net; p.johnston@niwa.co.nz; flittner@air.atmo.arizona.edu; brian.gardiner@bas.ac.uk; metcon@metcon-us.com RI Hofzumahaus, Andreas/I-9420-2012; Frost, Gregory/I-1958-2013; Pfister, Gabriele/A-9349-2008; Crawford, James/L-6632-2013; Krol, Maarten/E-3414-2013; Mayer, Bernhard/B-3397-2011; Krol, Maarten/B-3597-2010; Garmisch-Pa, Ifu/H-9902-2014; Krotkov, Nickolay/E-1541-2012; Madronich, Sasha/D-3284-2015; Bais, Alkiviadis/D-2230-2009; Swartz, William/A-1965-2010; Lefer, Barry/B-5417-2012; Monks, Paul/H-6468-2016; Kylling, Arve/B-1137-2017 OI Hofzumahaus, Andreas/0000-0003-2876-0880; Crawford, James/0000-0002-6982-0934; Mayer, Bernhard/0000-0002-3358-0190; Krotkov, Nickolay/0000-0001-6170-6750; Madronich, Sasha/0000-0003-0983-1313; Bais, Alkiviadis/0000-0003-3899-2001; Swartz, William/0000-0002-9172-7189; Lefer, Barry/0000-0001-9520-5495; Monks, Paul/0000-0001-9984-4390; Kylling, Arve/0000-0003-1584-5033 NR 59 TC 29 Z9 29 U1 0 U2 8 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 JUL 17 PY 2003 VL 108 IS D16 AR 8543 DI 10.1029/2002JD002891 PG 20 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 709BF UT WOS:000184604300001 ER PT J AU Gu, GJ Adler, RF Huffman, GJ Curtis, S AF Gu, GJ Adler, RF Huffman, GJ Curtis, S TI Summer synoptic-scale waves over West Africa observed by TRMM SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID EASTERLY WAVES; RAINFALL; ATLANTIC; DISTURBANCES; VARIABILITY; MONSOON; PACIFIC AB [1] A 5-year daily rainfall dataset (3B42) from TRMM is used to investigate the activity and properties of westward-propagating synoptic-scale waves [i.e., African easterly waves (AEW)] over tropical West Africa. Evident wave signals appearing in wavenumber-frequency space show their modulations on the surface rainfall pattern during the boreal summer. Interannual variability exists in both their intensity and spectral properties, i.e., dominant frequency and wavenumber ranges. These variabilities can be ascribed in part to year-to-year variations of their embedded large-scale environment, especially the mid-tropospheric African easterly jet (AEJ). Generally, a stronger (weaker) AEJ indicates more (less) instability energy, yielding a stronger (weaker) wave activity season. Both seasonal mean rainfall and AEWs were weak in 2001 but not in 1999. Consequently, there may exist a nonlinear relationship between the AEJ, AEWs and mean rainfall. To fully understand interannual variability of synoptic-scale waves over tropical West Africa, including the variability in the waves' preferred frequencies and wavenumbers, it is necessary to examine possible intra-seasonal variations in both wave activity and large-scale fields, in addition to their structure, propagation, and associated convection. C1 NASA, Atmospheres Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Maryland Baltimore Cty, Goddard Earth Sci & Technol Ctr, Baltimore, MD 21228 USA. Sci Syst & Applicat Inc, Lanham, MD USA. Univ Maryland Baltimore Cty, Joint Ctr Earth Syst Technol, Baltimore, MD 21228 USA. RP Gu, GJ (reprint author), NASA, Atmospheres Lab, Goddard Space Flight Ctr, Code 912, Greenbelt, MD 20771 USA. RI Curtis, Scott/C-1115-2013; Huffman, George/F-4494-2014 OI Huffman, George/0000-0003-3858-8308 NR 20 TC 4 Z9 4 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 JUL 16 PY 2003 VL 30 IS 14 AR 1729 DI 10.1029/2003GL017402 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 708YY UT WOS:000184599000006 ER PT J AU Wen, GY Cahalan, RF Holben, BN AF Wen, GY Cahalan, RF Holben, BN TI Limitations of ground-based solar irradiance estimates due to atmospheric variations SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE Langley plots; aerosols; AERONET; SORCE; SOLSTICE ID MAUNA-LOA; COMPARISON EXPERIMENT-1; SUN PHOTOMETRY; OPTICAL-DEPTH; VARIABILITY; CONSTANT; LUMINOSITY; AEROSOLS; MISSION; AERONET AB [1] The uncertainty in ground-based estimates of solar irradiance is quantitatively related to the temporal variability of the atmosphere's optical thickness. The upper and lower bounds of the accuracy of estimates using the Langley plot technique are proportional to the standard deviation of aerosol optical thickness (approximately +/-13sigma(deltatau)). The estimates of spectral solar irradiance in two Cimel Sun photometer channels at 340 and 380 nm from the Mauna Loa site of the Aerosol Robotic Network are compared with satellite observations from the Solar Stellar Irradiance Comparison Experiment (SOLSTICE) on the Upper Atmospheric Research Satellite for almost 2 years of data. The true solar variations related to the 27-day solar rotation cycle observed from SOLSTICE are similar to0.15% at the two Sun photometer channels. The variability in ground-based estimates is statistically 1 order of magnitude larger. Even though similar to30% of these estimates from all Level 2.0 Cimel data fall within the 0.4-0.5% variation level, ground-based estimates are not able to capture the 27-day solar variation observed from SOLSTICE. C1 NASA, Atmospheres Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Maryland Baltimore Cty, Joint Ctr Earth Syst Technol, Baltimore, MD 21228 USA. RP Wen, GY (reprint author), NASA, Atmospheres Lab, Goddard Space Flight Ctr, Code 661, Greenbelt, MD 20771 USA. EM wen@climate.gsfc.nasa.gov; cahalan@climate.gsfc.nasa.gov RI Cahalan, Robert/E-3462-2012 OI Cahalan, Robert/0000-0001-9724-1270 NR 31 TC 0 Z9 1 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 JUL 16 PY 2003 VL 108 IS D14 AR 4400 DI 10.1029/2003JD003431 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 709AT UT WOS:000184603100004 ER PT J AU Winfree, S Reinsch, S AF Winfree, S Reinsch, S TI XCTK1: A Xenopus C-terminal kinesin-like protein. SO DEVELOPMENTAL BIOLOGY LA English DT Meeting Abstract CT 62nd Annual Meeting of the Society-for-Development-Biology CY JUL 30-AUG 02, 2003 CL BOSTON, MASSACHUSETTS SP Soc Dev Biol C1 Lockheed Martin Inc, NASA, Ames Res Ctr, Moffett Field, CA USA. NR 0 TC 0 Z9 0 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 0012-1606 J9 DEV BIOL JI Dev. Biol. PD JUL 15 PY 2003 VL 259 IS 2 MA 136 BP 475 EP 475 PG 1 WC Developmental Biology SC Developmental Biology GA 705AD UT WOS:000184373300137 ER PT J AU Reinsch, SS Conway, GC AF Reinsch, SS Conway, GC TI The zebrafish G12 gene is required for nuclear positioning and cell migrations during early development. SO DEVELOPMENTAL BIOLOGY LA English DT Meeting Abstract CT 62nd Annual Meeting of the Society-for-Development-Biology CY JUL 30-AUG 02, 2003 CL BOSTON, MASSACHUSETTS SP Soc Dev Biol C1 NASA, Ames Res Ctr, Life Sci MS239 11, Moffett Field, CA USA. NR 0 TC 0 Z9 0 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 0012-1606 J9 DEV BIOL JI Dev. Biol. PD JUL 15 PY 2003 VL 259 IS 2 MA 399 BP 530 EP 531 PG 2 WC Developmental Biology SC Developmental Biology GA 705AD UT WOS:000184373300358 ER PT J AU Torrejon, M Nguyen, M Gupta, R Reinsch, S AF Torrejon, M Nguyen, M Gupta, R Reinsch, S TI Insertional mutagenesis screen for genes involved in vestibular/neural development in xenopus tropicalis. SO DEVELOPMENTAL BIOLOGY LA English DT Meeting Abstract CT 62nd Annual Meeting of the Society-for-Development-Biology CY JUL 30-AUG 02, 2003 CL BOSTON, MASSACHUSETTS SP Soc Dev Biol C1 NASA, Ames Res Ctr, Natl Res Council, Moffett Field, CA 94035 USA. NR 0 TC 0 Z9 0 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 0012-1606 J9 DEV BIOL JI Dev. Biol. PD JUL 15 PY 2003 VL 259 IS 2 MA 500 BP 554 EP 554 PG 1 WC Developmental Biology SC Developmental Biology GA 705AD UT WOS:000184373300450 ER PT J AU Lin, I Liu, WT Wu, CC Wong, GTF Hu, CM Chen, ZQ Liang, WD Yang, Y Liu, KK AF Lin, I Liu, WT Wu, CC Wong, GTF Hu, CM Chen, ZQ Liang, WD Yang, Y Liu, KK TI New evidence for enhanced ocean primary production triggered by tropical cyclone SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID SARGASSO SEA; HURRICANE; CHLOROPHYLL; NUTRIENTS; NITRATE AB [1] New evidence based on recent satellite data is presented to provide a rare opportunity in quantifying the long-speculated contribution of tropical cyclones to enhance ocean primary production. In July 2000, moderate cyclone Kai-Tak passed over the South China Sea (SCS). During its short 3-day stay, Kai-Tak triggered an average 30-fold increase in surface chlorophyll-a concentration. The estimated carbon fixation resulting from this event alone is 0.8 Mt, or 2-4% of SCS's annual new production. Given an average of 14 cyclones passing over the SCS annually, we suggest the long-neglected contribution of tropical cyclones to SCS's annual new production may be as much as 20-30%. C1 Natl Ctr Ocean Res, Taipei 10617, Taiwan. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Natl Taiwan Univ, Dept Atmospher Sci, Taipei 10764, Taiwan. Old Dominion Univ, Dept Ocean Earth & Atmospher Sci, Norfolk, VA 23529 USA. Univ S Florida, Coll Marine Sci, St Petersburg, FL 33701 USA. RP Lin, I (reprint author), Natl Ctr Ocean Res, POB 23-13, Taipei 10617, Taiwan. EM linii@ncor.ntu.edu.tw RI hu, chuanmin/J-5021-2012; Liu, Kon-Kee/K-8855-2012; Lin, I-I/J-4695-2013; OI Liu, Kon-Kee/0000-0003-4909-897X; Lin, I-I/0000-0002-8364-8106; Wu, Chun-Chieh/0000-0002-3612-4537 NR 14 TC 200 Z9 229 U1 4 U2 27 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 JUL 15 PY 2003 VL 30 IS 13 AR 1718 DI 10.1029/2003GL017141 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 708YV UT WOS:000184598700002 ER PT J AU Anyamba, A Justice, CO Tucker, CJ Mahoney, R AF Anyamba, A Justice, CO Tucker, CJ Mahoney, R TI Seasonal to interannual variability of vegetation and fires at SAFARI 2000 sites inferred from advanced very high resolution radiometer time series data SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE normalized difference vegetation index; El Nino; La Nina; fire dynamics; southern Africa; interannual climate dynamics ID SOUTHERN AFRICAN RAINFALL; AVHRR DATA; NOAA AVHRR; EL-NINO; SUMMER RAINFALL; INDEX; OSCILLATION; SATELLITE; DYNAMICS; NDVI AB [1] NOAA advanced very high resolution radiometer data are used to place the SAFARI 2000 and SAFARI 1992 intensive campaigns in the context of the interannual variability of vegetation conditions in southern Africa. Normalized difference vegetation index (NDVI) measurements and sea surface temperature (SST) indices of El Nino/Southern Oscillation (ENSO) are compared and the connections explained. The paper shows the vegetation evolution for the 2000 growing season, with unprecedented high and persistent NDVI anomalies associated with a cold phase of ENSO (La Nina) and above average rainfall between November and May, south of 15degreesS. In contrast, the 1992 season showed marked negative NDVI anomalies associated with an extreme drought in the southern part of the region, associated with the warm phase of ENSO (El Nino). These differences in NDVI patterns resulted in different patterns of fire distribution. More satellite detections of active fires were observed in 2000 than in 1992, especially for Botswana, Namibia, southern Zimbabwe, and southern Mozambique. Comparisons between in situ airborne measurements collected in 2000 and 1992 require an understanding of the extremely different vegetation and fire conditions associated with those years. Generalizations from results of the two SAFARI campaigns should be made with careful consideration of the extreme differences in conditions and the large interannual variability encountered in southern Africa, as depicted by the long-term record of satellite vegetation measurements. C1 Univ Maryland, Goddard Earth Sci Technol Ctr, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Biospher Sci Branch, Greenbelt, MD 20771 USA. Univ Maryland, Dept Geog, College Pk, MD 20742 USA. Global Sci & Technol, Greenbelt, MD 20770 USA. RP Anyamba, A (reprint author), Univ Maryland, Goddard Earth Sci Technol Ctr, Greenbelt, MD 20771 USA. EM assaf@ltpmail.gsfc.nasa.gov; justice@hermes.geog.umd.edu; compton@ltpmail.gsfc.nasa.gov; mahoney@mombasa.gsfc.nasa.gov NR 44 TC 22 Z9 22 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 JUL 15 PY 2003 VL 108 IS D13 AR 8507 DI 10.1029/2002JD002464 PG 26 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 709AC UT WOS:000184601700004 ER PT J AU Buermann, W Anderson, B Tucker, CJ Dickinson, RE Lucht, W Potter, CS Myneni, RB AF Buermann, W Anderson, B Tucker, CJ Dickinson, RE Lucht, W Potter, CS Myneni, RB TI Interannual covariability in Northern Hemisphere air temperatures and greenness associated with El Nino-Southern Oscillation and the Arctic Oscillation SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE NDVI; temperature; ENSO; AO; interannual variability; canonical correlation analysis ID CANONICAL CORRELATION-ANALYSIS; SEA-SURFACE TEMPERATURE; VEGETATION INDEX; GROWING-SEASON; EXTRATROPICAL CIRCULATION; GEOPOTENTIAL HEIGHT; ATMOSPHERIC CO2; CLIMATE-CHANGE; ANNULAR MODES; WHITE SPRUCE AB [1] In this paper, we estimate the year-to-year variations in northern vegetation greenness as they relate to the dominant modes of climate variability. In particular, we analyze spatial data of Northern Hemisphere satellite-sensed vegetation greenness, surface temperature, precipitation, and upper air data for the 1982-1998 period to isolate well correlated modes of variability between temperature and greenness and to assess their relationship to large-scale circulation anomalies. It is found that during spring, large-scale modes of interannual vegetation variability are strongly correlated with spatiotemporal modes of variability in the overlying temperature field. In addition, the results indicate that the two predominant hemispheric-scale modes of covariability are related to teleconnections associated with the El Nino-Southern Oscillation (ENSO) and the Arctic Oscillation (AO). The warm event ENSO signal is manifested as warmer and greener conditions in North America, Far East Asia, and to some extent central Europe, while the features of the positive phase AO signal include enhanced warm and green conditions over large regions in Europe and Asian Russia, with opposite anomalies in the eastern half of North America. Whether observed trends in vegetation activity over the past 20 years are also related to systematic changes in these two modes of variability is still unclear. C1 Univ Calif Berkeley, Ctr Atmospher Sci, Berkeley, CA 94720 USA. Boston Univ, Dept Geog, Boston, MA 02215 USA. NASA, Biol Sci Branch, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Georgia Inst Technol, Sch Earth & Atmospher Sci, Atlanta, GA 30332 USA. Potsdam Inst Climate Impact Res, D-14412 Potsdam, Germany. NASA, Ecosyst Sci & Technol Branch, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Buermann, W (reprint author), Univ Calif Berkeley, Ctr Atmospher Sci, 150 Hilgard, Berkeley, CA 94720 USA. EM buermann@atmos.berkeley.edu; brucea@bu.edu; compton@ltpmail.gsfc.nasa.gov; robted@eas.gatech.edu; wolfgang.lucht@pik-potsdam.de; cpotter@gaia.arc.nasa.gov; rmyneni@bu.edu RI Lucht, Wolfgang/G-2180-2011; Myneni, Ranga/F-5129-2012 OI Lucht, Wolfgang/0000-0002-3398-8575; NR 58 TC 68 Z9 70 U1 3 U2 26 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 JUL 15 PY 2003 VL 108 IS D13 AR 4396 DI 10.1029/2002JD002630 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 709AC UT WOS:000184601700005 ER PT J AU Queface, AJ Piketh, SJ Annegarn, HJ Holben, BN Uthui, RJ AF Queface, AJ Piketh, SJ Annegarn, HJ Holben, BN Uthui, RJ TI Retrieval of aerosol optical thickness and size distribution from the CIMEL Sun photometer over Inhaca Island, Mozambique SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE aerosol optical properties; SAFARI 2000; biomass burning; single scattering albedo ID SOUTHERN AFRICA; SAFARI 2000; CAMPAIGN; AERONET; DEPTH; VARIABILITY; SPACE; FIRES AB [1] Characterization of aerosol optical properties over southern Africa is needed to better understand the impact of aerosols on regional climate change. CIMEL Sun photometer measurements of aerosol optical thickness over Inhaca Island, Mozambique, between April and November 2000 are analyzed. Comparisons with two other sites, Mongu, Zambia, and Bethlehem, South Africa, are made. The aerosol optical thickness observed at Inhaca Island indicates high turbidity. In similar to50% of the measurements, aerosol optical thickness values are above 0.2, with an overall mean of 0.26 +/- 0.19. The Angstrom exponent parameter has a wide range from 0.2 to 2, with a modal value of 1.6. This indicates a wide range in particle sizes and the dominance of fine mode aerosols at this site. Data from all three sites reveal seasonal variability, with a significant increase in aerosol content between August and October. This suggests a strong contribution of biomass burning to the atmospheric aerosols content during this time of year, which corresponds to the period of maximum burning in southern Africa. A north to south gradient in aerosol optical thickness is confirmed. The highest aerosol content is observed over Mongu, while Bethlehem has the lowest. The retrieved aerosol volume size distribution over Inhaca Island demonstrates that at high levels of aerosol optical thickness, accumulation mode aerosols dominate. In contrast, coarse mode aerosols dominate when aerosol optical thickness is very low. It is noted that there is a tendency for decreasing particle size as aerosol optical thickness increases, with the peak in distribution of the accumulation mode volume radius decreasing from 0.19 mum at tau(a) = 0.42 to similar to0.14 mum at tau(a) = 1.12. C1 Univ Witwatersrand, Climatol Res Grp, ZA-2050 Wits, South Africa. Eduardo Mondlane Univ, Dept Phys, Maputo, Mozambique. Univ Witwatersrand, Atmosphere & Energy Res Grp, ZA-2050 Wits, South Africa. NASA, Biospher Sci Branch, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Queface, AJ (reprint author), Univ Witwatersrand, Climatol Res Grp, Private Bag 3, ZA-2050 Wits, South Africa. EM queface@hotmail.com; stuart@crg.bpb.wits.ac.za; annegarn@src.wits.ac.za; brent@spamer.gsfc.nasa.gov; uthui@zebra.uem.mz RI Annegarn, Harold/A-9127-2008 OI Annegarn, Harold/0000-0001-6653-4679 NR 19 TC 8 Z9 8 U1 0 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 JUL 15 PY 2003 VL 108 IS D13 AR 8509 DI 10.1029/2002JD002374 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 709AC UT WOS:000184601700002 ER PT J AU Swap, RJ Annegarn, HJ Suttles, JT King, MD Platnick, S Privette, JL Scholes, RJ AF Swap, RJ Annegarn, HJ Suttles, JT King, MD Platnick, S Privette, JL Scholes, RJ TI Africa burning: A thematic analysis of the Southern African Regional Science Initiative (SAFARI 2000) SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE SAFARI 2000; southern Africa; biomass burning; emission factors; aerosols; radiation forcing ID TRANSFORM INFRARED-SPECTROSCOPY; SINGLE SCATTERING ALBEDO; LEAF-LEVEL MEASUREMENTS; SEASON FIELD CAMPAIGN; DRY-SEASON; TRACE GAS; SAVANNA FIRES; OPTICAL-PROPERTIES; AEROSOL-PARTICLES; STABLE DISCONTINUITIES AB [1] The Southern African Regional Science Initiative (SAFARI 2000) was a major surface, airborne, and spaceborne field campaign carried out in southern Africa in 2000 and 2001 that addressed a broad range of phenomena related to land-atmosphere interactions and the biogeochemical functioning of the southern African system. This paper presents a thematic analysis and integration of the Journal of Geophysical Research SAFARI 2000 Special Issue, presenting key findings of an intensive field campaign over southern Africa in August and September of 2000. The integrating themes deal with surface emissions characterization; airborne characterizations of aerosols and trace gases; regional haze and trace gas characterization; and radiant measurements by surface, aircraft, and remote sensing platforms. Enhanced regional fuel loads associated with the moist La Nina phase of the El Nino-Southern Oscillation (ENSO) cycle produced above average biomass burning emissions, which consequently dominated all other aerosol and trace gas emissions during the dry season. Southward transport of a broad plume of smoke originating in equatorial Africa and exiting off the east coast toward the Indian Ocean (the river of smoke) is attributed to unusual synoptic airflows associated the ENSO phase. New and revised biogenic and pyrogenic emission factors are reported, including a number of previously unreported oxygenated organic compounds and inorganic compounds from biomass combustion. Emission factors are scaled up to regional emission surfaces for biogenic species utilizing species specific and light-dependent emission factors. Fire scar estimates reveal contradictory information on the timing of the peak and extent of the biomass-burning season. Integrated tall stack coordinated measurements (between ground, airborne and remotely sensing platforms) of upwelling and downwelling radiation in massive thick aerosol layers covering much of southern Africa yield consistent estimates of large negative forcing for both surface and top of atmosphere radiative forcing. Radiation calculations are supported by novel information on chemical speciation and internal aerosol particle structure. The overall conclusion is that SAFARI 2000, as an integrating theme, has been able to give significant new insights into the regional scale biogeochemical cycling of southern Africa and contributed in important ways to the validation of remote sensing instruments on board the NASA Terra spacecraft. C1 Univ Virginia, Dept Environm Sci, Charlottesville, VA 22904 USA. Univ Witwatersrand, Atmosphere & Energy Res Grp, ZA-2050 Johannesburg, South Africa. Sci Syst & Applicat Inc, Lanham, MD 20706 USA. NASA, Earth Sci Directorate, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NASA, Atmospheres Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NASA, Terr Phys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. CSIR, Div Water Environm & Forestry Technol, ZA-0001 Pretoria, South Africa. RP Univ Virginia, Dept Environm Sci, Charlottesville, VA 22904 USA. EM rjs8g@virginia.edu; annegarn@src.wits.ac.za; 4suttles@bellsouth.net; michael.d.king@nasa.gov; steven.platnick@nasa.gov; jeffrey.l.privette@nasa.gov; bscholes@csir.co.za RI Privette, Jeffrey/G-7807-2011; King, Michael/C-7153-2011; Annegarn, Harold/A-9127-2008; Platnick, Steven/J-9982-2014 OI Privette, Jeffrey/0000-0001-8267-9894; King, Michael/0000-0003-2645-7298; Annegarn, Harold/0000-0001-6653-4679; Platnick, Steven/0000-0003-3964-3567 NR 75 TC 127 Z9 130 U1 0 U2 0 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 JUL 15 PY 2003 VL 108 IS D13 AR 8465 DI 10.1029/2003JD003747 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 709AC UT WOS:000184601700007 ER PT J AU Rubincam, DP AF Rubincam, DP TI Gravitational core-mantle coupling and the acceleration of the Earth SO JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH LA English DT Article DE core; mantle; core-mantle coupling; rotation; acceleration; drift ID ROTATION; MODEL; RISE; FLOW AB Gravitational core-mantle coupling may be the cause of the observed variable acceleration of the Earth's rotation on the 1000-year timescale. Density inhomogeneities which randomly come and go in the liquid outer core may gravitationally attract density inhomogeneities in the mantle (and crust), torquing the mantle and changing its rotation state. The corresponding torque by the mantle on the core may also explain the westward drift of the magnetic field of 0.2degrees yr(-1). Gravitational core-mantle coupling would stochastically affect the rate of change of the Earth's obliquity by just a few percent. Its contribution to polar wander would only be similar to0.5% the presently observed rate. C1 NASA, Goddard Space Flight Ctr, Terr Phys Lab, Geodynam Branch, Greenbelt, MD 20771 USA. RP Rubincam, DP (reprint author), NASA, Goddard Space Flight Ctr, Terr Phys Lab, Geodynam Branch, Code 921, Greenbelt, MD 20771 USA. EM David.P.Rubincam@nasa.gov RI Rubincam, David/D-2918-2012 NR 22 TC 1 Z9 1 U1 0 U2 0 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 JUL 15 PY 2003 VL 108 IS B7 AR 2338 DI 10.1029/2002JB002132 PG 5 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 825VT UT WOS:000221787300001 ER PT J AU Ricca, A Bauschlicher, CW Maiti, A AF Ricca, A Bauschlicher, CW Maiti, A TI Comparison of the reactivity of O-2 with a (10,0) and a (9,0) carbon nanotube SO PHYSICAL REVIEW B LA English DT Article ID GEOMETRY OPTIMIZATION; ELECTRONIC-STRUCTURE; MOLECULAR-MECHANICS; ADSORPTION; APPROXIMATION; EXCHANGE; MODELS AB The physisorption and chemisorption of O-2 on the inner and outer walls of a (10,0) carbon nanotube have been studied using the ONIOM method and the second-order Moller-Plesset correlation treatment, which includes long-range dispersion interactions. The results have been compared to those previously computed for a (9,0) carbon nanotube interacting with O-2. Overall, the reactivity of a (10,0) nanotube with O-2 is very similar to that of a (9,0) nanotube. Our results indicate that oxygen exposure on a (10,0) carbon nanotube under normal conditions has no doping effect to enhance the conductivity. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Accelrys Inc, San Diego, CA 92121 USA. RP ELORET Corp, Mail Stop 230-3, Moffett Field, CA 94035 USA. EM ricca@pegasus.arc.nasa.gov NR 32 TC 43 Z9 44 U1 0 U2 6 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2469-9950 EI 2469-9969 J9 PHYS REV B JI Phys. Rev. B PD JUL 15 PY 2003 VL 68 IS 3 AR 035433 DI 10.1103/PhysRevB.68.035433 PG 7 WC Physics, Condensed Matter SC Physics GA 719XD UT WOS:000185229600147 ER PT J AU Wu, J Walukiewicz, W Yu, KM Shan, W Ager, JW Haller, EE Miotkowski, I Ramdas, AK Su, CH AF Wu, J Walukiewicz, W Yu, KM Shan, W Ager, JW Haller, EE Miotkowski, I Ramdas, AK Su, CH TI Composition dependence of the hydrostatic pressure coefficients of the bandgap of ZnSe1-xTex alloys SO PHYSICAL REVIEW B LA English DT Article ID DIRECT ABSORPTION-EDGE; SEMICONDUCTOR ALLOYS; GAASN AB Optical absorption experiments were performed using diamond-anvil cells to measure the hydrostatic pressure dependence of the fundamental bandgap of ZnSe1-xTex alloys over the entire composition range. The first- and second-order pressure coefficients were obtained as a function of composition. The coefficients do not vary linearly between the ZnSe and ZnTe end-point values. Starting from the ZnSe side, the magnitude of both coefficients increases slowly until xapproximate to0.7, which is the point where the ambient-pressure bandgap shows a minimum. At larger values of x the coefficients rapidly approach the values of ZnTe. The large deviations of the pressure coefficients from the linear interpolation between ZnSe and ZnTe are explained in terms of the band anticrossing model. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Mat Sci & Engn, Berkeley, CA 94720 USA. Purdue Univ, Dept Phys, W Lafayette, IN 47907 USA. NASA, Sci Directorate SD46, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Wu, J (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Mat Sci, Berkeley, CA 94720 USA. RI Wu, Junqiao/G-7840-2011; Yu, Kin Man/J-1399-2012 OI Wu, Junqiao/0000-0002-1498-0148; Yu, Kin Man/0000-0003-1350-9642 NR 17 TC 17 Z9 17 U1 0 U2 1 PU AMERICAN 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 JUL 15 PY 2003 VL 68 IS 3 AR 033206 DI 10.1103/PhysRevB.68.033206 PG 4 WC Physics, Condensed Matter SC Physics GA 719XD UT WOS:000185229600012 ER PT J AU Pruessner, MW King, TT Kelly, DP Grover, R Calhoun, LC Ghodssi, R AF Pruessner, MW King, TT Kelly, DP Grover, R Calhoun, LC Ghodssi, R TI Mechanical property measurement of InP-based MEMS for optical communications SO SENSORS AND ACTUATORS A-PHYSICAL LA English DT Article DE optical MEMS; InP; nanoindentation; bending test; MBE growth ID FABRY-PEROT FILTERS; THIN-FILMS; NANOINDENTATION; POLYSILICON; NETWORKS; DEVICES; SYSTEMS AB We investigate mechanical properties of indium phosphide (InP) for optical micro-electro-mechanical systems (MEMS) applications. A material system and fabrication process for InP-based beam-type electrostatic actuators is presented. Strain gradient, intrinsic stress, Young's modulus, and hardness are evaluated by beam profile measurements, nanoindentation, beam bending, and electrostatic testing methods. We measured an average strain gradient of deltaepsilon(0)/delta(t) = 4.37 x 10(-5) mum(-1), with an average intrinsic stress of sigma(0) = -5.4 MPa for [011] beams. The intrinsic stress results from arsenic contamination during molecular beam epitaxy and (MBE) can be minimized by careful MBE growth and through the use of stress compensating layers. Nanoindentation of (100) InP resulted in E = 106.5 GPa and H = 6.2 GPa, while beam bending of [011] doubly clamped beams resulted in E = 80.4 GPa and sigma(0) = -5.6 MPa. We discuss the discrepancy in Young's modulus between the two measurements. In addition, we present a method for simultaneously measuring Young's modulus and residual stress using beam bending. Electrostatic actuation in excess of 20 V is demonstrated without breakdown. (C) 2003 Elsevier Science B.V. All rights reserved. C1 Univ Maryland, MSAL, Dept Elect & Comp Engn, Syst Res Inst, College Pk, MD 20742 USA. Lab Phys Sci, College Pk, MD 20740 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Ghodssi, R (reprint author), Univ Maryland, MSAL, Dept Elect & Comp Engn, Syst Res Inst, AV Williams Bldg, College Pk, MD 20742 USA. NR 28 TC 46 Z9 48 U1 0 U2 7 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0924-4247 J9 SENSOR ACTUAT A-PHYS JI Sens. Actuator A-Phys. PD JUL 15 PY 2003 VL 105 IS 2 BP 190 EP 200 DI 10.1016/S0924-4247(03)00102-X PG 11 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA 691MP UT WOS:000183610300008 ER PT J AU Zellweger, A AF Zellweger, A TI Simulation in CNS/ATM research with examples from the United States SO SIMULATION MODELLING PRACTICE AND THEORY LA English DT Article; Proceedings Paper CT Eurosim 2001 International Congress CY JUN 26-29, 2001 CL DELFT, NETHERLANDS DE real time simulation; fast time simulation; models; air traffic management; air traffic control AB Technology advances, particularly in computer hardware and software, have made simulation an essential tool in Communications, Navigation, and Surveillance/Air Traffic Management (CNS/ATM) research and development. Both real and fast time simulations find use in applications ranging from early concept exploration to pre-operational laboratory testing. ATM research labs throughout the world are making common use of these tools. They range from relatively small-scale labs at universities to costly high fidelity cockpit and ATC simulators at major government labs, such as NASA Ames Research Center. Networked simulators are making it possible to study the complex interactions of numerous actors (computers and people), possibly with new roles, in future ATM systems. (C) 2002 Elsevier B.V. All rights reserved. C1 Embry Riddle Aeronaut Univ, Daytona Beach, FL 32114 USA. RP Zellweger, A (reprint author), NASA, Aviat Off Aerosp Technol, Code R 300 E St SW, Washington, DC 20546 USA. NR 20 TC 3 Z9 3 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1569-190X J9 SIMUL MODEL PRACT TH JI Simul. Model. Pract. Theory PD JUL 15 PY 2003 VL 11 IS 3-4 BP 173 EP 185 DI 10.1016/S1569-190X(02)00088-6 PG 13 WC Computer Science, Interdisciplinary Applications; Computer Science, Software Engineering SC Computer Science GA 709NJ UT WOS:000184631000002 ER PT J AU Lamberti, L Venkataraman, S Haftka, RT Johnson, TF AF Lamberti, L Venkataraman, S Haftka, RT Johnson, TF TI Preliminary design optimization of stiffened panels using approximate analysis models SO INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING LA English DT Article DE preliminary design optimization; stiffened shell structures ID MINIMUM-WEIGHT DESIGN; COMBINED INPLANE LOADS; OPTIMUM DESIGN; CYLINDRICAL-SHELLS; COMPOSITE; PROGRAM; IMPERFECT; PANDA2 AB Preliminary sizing of structural components in the conceptual design phase of new aerospace vehicles requires a large number of structural optimizations. Use of detailed finite element models for global optimization of stiffened shell structures is not affordable. Designers have to compromise between the complexity in the structural analysis model (e.g. small models or linear analysis) and that of the optimization method (local versus global optimization). When designing new concepts where good initial designs are not available, global design optimization needs to be performed, and this is not currently possible with complex models. In this paper, we discuss the use of simple analysis methods for performing global optimization of stiffened shell structures. We demonstrate the efficiency of using approximate analysis models by using PANDA2 for a practical design trade-study. Often approximate models are based on assumptions that are not satisfied throughout the design space. Hence, such models require constraints that will keep the designs in regions where the analysis assumptions are valid. We illustrate with examples situations where such design constraints result in sub-optimal designs. We conclude that performing global optimization using approximate methods can permit a greater exploration of the design space than the use of local optimization with complex models. Copyright (C) 2003 John Wiley Sons, Ltd. C1 San Diego State Univ, Dept Aerosp Engn & Engn Mech, San Diego, CA 92182 USA. Politecn Bari, Dipartimento Projettiazone & Ingn Meccan & Gest, I-70126 Bari, Italy. Univ Florida, Dept Mech & Aerosp Engn, Gainesville, FL 32611 USA. NASA, Langley Res Ctr, Mech & Durabil, Hampton, VA 23681 USA. RP Venkataraman, S (reprint author), San Diego State Univ, Dept Aerosp Engn & Engn Mech, 5500 Campanile Dr,Mail Code 1308, San Diego, CA 92182 USA. OI LAMBERTI, Luciano/0000-0002-9845-8786 NR 38 TC 32 Z9 34 U1 1 U2 3 PU JOHN WILEY & SONS LTD PI CHICHESTER PA THE ATRIUM, SOUTHERN GATE, CHICHESTER PO19 8SQ, W SUSSEX, ENGLAND SN 0029-5981 J9 INT J NUMER METH ENG JI Int. J. Numer. Methods Eng. PD JUL 14 PY 2003 VL 57 IS 10 BP 1351 EP 1380 DI 10.1002/nme.781 PG 30 WC Engineering, Multidisciplinary; Mathematics, Interdisciplinary Applications SC Engineering; Mathematics GA 699HC UT WOS:000184050100003 ER PT J AU Thompson, RJ Tu, M Aveline, DC Lundblad, N Maleki, L AF Thompson, RJ Tu, M Aveline, DC Lundblad, N Maleki, L TI High power single frequency 780nm laser source generated from frequency doubling of a seeded fiber amplifier in a cascade of PPLN crystals SO OPTICS EXPRESS LA English DT Article ID 2ND-HARMONIC GENERATION AB We report on the generation of over 900 mW of tunable cw light at 780 nm by single pass frequency doubling of a high power fiber amplifier in a cascade of two periodically poled Lithium Niobate ( PPLN) crystals. Over 500 mW is generated in the first crystal. In the limit of low pump power, we observe an efficiency of 4.6 mW/W-2-cm for a single crystal, and 5.6 mW/W-2-cm for a combination of two crystals, with an enhancement of the doubling efficiency observed with two crystals due to the presence of second harmonic light from the first crystal acting as a seed for the second. We have frequency locked this laser source relative to a rubidium D2 hyperfine line and demonstrated its utility in a sophisticated laser cooling apparatus. (C) 2003 Optical Society of America. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Thompson, RJ (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM Robert.J.Thompson@JPL.nasa.gov RI Lundblad, Nathan/A-9965-2009 OI Lundblad, Nathan/0000-0003-0430-8064 NR 6 TC 44 Z9 47 U1 1 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 JUL 14 PY 2003 VL 11 IS 14 BP 1709 EP 1713 DI 10.1364/OE.11.001709 PG 5 WC Optics SC Optics GA 702BB UT WOS:000184203800014 PM 19466050 ER PT J AU Lin, II Alpers, W Liu, WT AF Lin, II Alpers, W Liu, WT TI First evidence for the detection of natural surface films by the QuikSCAT scatterometer SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article AB [1] For the first time it is demonstrated that with the QuikSCAT scatterometer it is possible to detect natural surface films resulting from enhanced biological activity in the ocean. It is shown for two regions in the Norwegian and Baltic Sea that areas of strongly reduced Normalized Radar Cross Section (NRCS) are associated with areas of enhanced chlorophyll-a concentration as evidenced by quasi-simultaneously acquired SeaWiFS data. This result has two implications. Firstly, it opens up the possibility to map globally natural surface film coverage using QuikSCAT data. Secondly, it demonstrates that in ocean areas with high biological activity the presence of natural surface films can give rise to significant errors in wind vector retrieval when using the current QuikSCAT wind retrieval algorithm. C1 Natl Ctr Ocean Res, Taipei 10617, Taiwan. Univ Hamburg, Inst Oceanog, Hamburg, Germany. NASA, Jet Prop Lab, Washington, DC 20546 USA. RP Lin, II (reprint author), Natl Ctr Ocean Res, POB 23-13, Taipei 10617, Taiwan. RI Lin, I-I/J-4695-2013 OI Lin, I-I/0000-0002-8364-8106 NR 12 TC 4 Z9 4 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 JUL 12 PY 2003 VL 30 IS 13 AR 1713 DI 10.1029/2003GL017415 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 704KK UT WOS:000184338700004 ER PT J AU Colarco, PR Toon, OB Holben, BN AF Colarco, PR Toon, OB Holben, BN TI Saharan dust transport to the Caribbean during PRIDE: 1. Influence of dust sources and removal mechanisms on the timing and magnitude of downwind aerosol optical depth events from simulations of in situ and remote sensing observations SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE dust aerosols; transport model; dust sources; long-range transport; dust removal mechanisms ID GENERAL-CIRCULATION MODEL; SKY RADIANCE MEASUREMENTS; MINERAL DUST; RADIATIVE PROPERTIES; SIZE DISTRIBUTION; 3-DIMENSIONAL SIMULATION; TROPOSPHERIC AEROSOLS; CLIMATE MODEL; WIND EROSION; SENSITIVITY AB [1] Dust emissions, transport, and deposition are simulated for the Puerto Rico Dust Experiment (June-July, 2000) with a three-dimensional aerosol transport model driven by assimilated meteorology. Sensitivity to the dust source formulation is tested by comparing simulations run with two different source modules to TOMS and AERONET measurements. Central and east African dust sources are more accurately simulated with the Ginoux et al. [2001] source model than with the Marticorena and Bergametti [1995] source model. The timing of high aerosol optical depth (AOD) dust events at Puerto Rico is largely independent of the timing of dust emissions, implying a persistent reservoir of suspended dust particles exists over Africa and that the timing of downwind dust events is more strongly coupled to transport dynamics than to the dust source model chosen. The downwind AOD and particle size distribution are accurately simulated using the dust particle size distribution produced by the Ginoux et al. [2001] source model or by fitting the Marticorena and Bergametti [1995] dust emissions to the d'Almeida [1987] background desert aerosol particle size distribution. The dust distribution determined by fitting the Marticorena and Bergametti [1995] emissions to the Schulz et al. [1998] initial particle size distribution produces aerosol optical depths that are consistently too high. Large dust particles observed far downwind of source areas may be partially explained if they are treated as flat disks rather than spheres in the particle fall velocity calculation. With the Ginoux et al. [2001] source model we estimate African and Arabian dust emissions during July 2000 to be 214 Tg for particles smaller than 10 mm radius. Nineteen percent of the emitted mass is transported west of Africa and over the North Atlantic. Twenty percent of the dust leaving Africa passes west of Puerto Rico. C1 Univ Colorado, Program Atmospher & Ocean Sci, Atmospher & Space Phys Lab, Boulder, CO 80309 USA. NASA, Terr Phys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Univ Maryland Baltimore Cty, Goddard Earth Sci & Technol Ctr, NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. EM peter.colarco@gsfc.nasa.gov RI Welton, Ellsworth/A-8362-2012; Campbell, James/C-4884-2012; Colarco, Peter/D-8637-2012; Levy, Robert/M-7764-2013; Reid, Jeffrey/B-7633-2014 OI Campbell, James/0000-0003-0251-4550; Colarco, Peter/0000-0003-3525-1662; Levy, Robert/0000-0002-8933-5303; Reid, Jeffrey/0000-0002-5147-7955 NR 67 TC 73 Z9 72 U1 0 U2 4 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 JUL 12 PY 2003 VL 108 IS D19 AR 8589 DI 10.1029/2002JD002658 PG 20 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 705YB UT WOS:000184423900002 ER PT J AU Reid, JS Jonsson, HH Maring, HB Smirnov, A Savoie, DL Cliff, SS Reid, EA Livingston, JM Meier, MM Dubovik, O Tsay, SC AF Reid, JS Jonsson, HH Maring, HB Smirnov, A Savoie, DL Cliff, SS Reid, EA Livingston, JM Meier, MM Dubovik, O Tsay, SC TI Comparison of size and morphological measurements of coarse mode dust particles from Africa SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE dust; measurement; impactor; optical particle counter; inversion; size distribution ID AEROSOL OPTICAL-PROPERTIES; SKY BRIGHTNESS MEASUREMENTS; SAHARAN DUST; MINERAL DUST; RADIANCE MEASUREMENTS; LIGHT-SCATTERING; RADIATIVE CHARACTERISTICS; TROPOSPHERIC AEROSOLS; VERTICAL-DISTRIBUTION; INDIVIDUAL-PARTICLE AB [1] A multitude of sensitivity studies in the literature point to the importance of proper chemical and morphological characterization of particles when the radiative impacts of airborne dusts are modeled. However, the community data set is based on heterogeneous measurement methods relying on varying aerodynamic, chemical, morphological, and optical means. During the Puerto Rico Dust Experiment, size distributions of dust particles from Africa were measured using a variety of aerodynamic, optical, and geometric means. Consistent with the literature, comparisons of these size distributions showed quite dissimilar results. "Measured'' volume median diameters varied from 2.5 to 9 mum for various geometric, aerodynamic, optical, and optical inversion methods. Aerodynamic systems showed mixed performance. Column integrated size distributions inverted from AERONET Sun/sky radiance data produced somewhat reasonable results in the coarse mode when given proper constraints and taken in the proper context. The largest systematic errors were found in optical particle counters due to insensitivities to particle size in the 4-10 mum region with further complications due to dust particle morphology and index of refraction issues. As these methods can produce quite dissimilar size distributions, considerable errors in calculated radiative properties can occur if incorrectly modeled into dust parameters. None of the methods compared in this study can adequately reproduce the measured mass extinction or mass scattering efficiency of the dust using spherical geometry methods. Given all of the uncertainties in the sizing methods, we promote the use of fundamental and quantifiable descriptors of particles such as mass as a function of aerodynamic diameter. C1 Space & Naval Warfare Syst Ctr San Diego, San Diego, CA USA. USN, Postgrad Sch, Monterey, CA 93943 USA. Univ Miami, Rosenstiel Sch Marine & Atmospher Sci, Miami, FL 33149 USA. Univ Maryland Baltimore Cty, GEST Ctr, Baltimore, MD 21250 USA. Univ Calif Davis, DELTA Grp, Davis, CA 95616 USA. USN, Res Lab, Monterey, CA 93943 USA. SRI Int, Palo Alto, CA 94025 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP USN, Res Lab, 7 Grace Hopper St, Monterey, CA 93943 USA. EM reidj@nrlmry.navy.mil RI Dubovik, Oleg/A-8235-2009; Smirnov, Alexander/C-2121-2009; Reid, Jeffrey/B-7633-2014; Tsay, Si-Chee/J-1147-2014 OI Dubovik, Oleg/0000-0003-3482-6460; Smirnov, Alexander/0000-0002-8208-1304; Reid, Jeffrey/0000-0002-5147-7955; NR 76 TC 133 Z9 133 U1 3 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 JUL 12 PY 2003 VL 108 IS D19 AR 8593 DI 10.1029/2002JD002485 PG 28 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 705YB UT WOS:000184423900001 ER PT J AU Joughin, I Rignot, E Rosanova, CE Lucchitta, BK Bohlander, J AF Joughin, I Rignot, E Rosanova, CE Lucchitta, BK Bohlander, J TI Timing of recent accelerations of Pine Island Glacier, Antarctica SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID SATELLITE RADAR INTERFEROMETRY; WEST ANTARCTICA; ICE STREAMS; MASS-BALANCE; MODEL; SHEET; FLOW AB [1] We have used Interferometric Synthetic Aperture Radar (InSAR) data and sequential Landsat imagery to identify and temporally constrain two acceleration events on Pine Island Glacier (PIG). These two events are separated by a period of at least seven years (1987-1994). The change in discharge between two flux gates indicates that the majority of the increase in discharge associated with the second acceleration originates well inland (>80 km) from the grounding line. An analysis indicates that changes in driving stress consistent with observed thinning rates are sufficient in magnitude to explain much of the acceleration. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Nat Resources Conservat Serv, Bozeman, MT 59715 USA. US Geol Survey, Flagstaff, AZ 86001 USA. Univ Colorado, Natl Snow & Ice Data Ctr, Boulder, CO 80309 USA. RP Joughin, I (reprint author), CALTECH, Jet Prop Lab, M-S 300-235, Pasadena, CA 91109 USA. RI Joughin, Ian/A-2998-2008; Rignot, Eric/A-4560-2014 OI Joughin, Ian/0000-0001-6229-679X; Rignot, Eric/0000-0002-3366-0481 NR 28 TC 104 Z9 104 U1 0 U2 8 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 JUL 11 PY 2003 VL 30 IS 13 AR 1706 DI 10.1029/2003GL017609 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 704KJ UT WOS:000184338600005 ER PT J AU Leroy, SS Yung, YL Richardson, MI Wilson, RJ AF Leroy, SS Yung, YL Richardson, MI Wilson, RJ TI Principal modes of variability of Martian atmospheric surface pressure SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID MID-LATITUDE DISTURBANCES; GENERAL-CIRCULATION MODEL; EXTRATROPICAL CIRCULATION; NORTHERN-HEMISPHERE; CLIMATE-CHANGE; ANNULAR MODES; MARS; SIMULATION; DYNAMICS; WAVES AB [1] An analysis of daily-to-interannual variability in the surface pressure field of the Martian nothern hemisphere as given by a Martian climate model is presented. In an empirical orthogonal function (EOF) decomposition, the dominant first two modes of variability comprise a zonal wavenumber 1 feature centered at 70 N latitude moving eastward with a period of 6 to 8 sols. This feature is a baroclinic wave and accounts for 53% of the northern hemisphere non-stationary surface pressure variability, and, when active, has an amplitude of up to 2% of local surface pressure. The third mode of the EOF decomposition is annular about the Martian north pole, is null southward of 70 N, and accounts for 7% of the northern hemisphere non-stationary surface pressure variability. The baroclinic wave (EOFs 1 & 2) is active during northern hemisphere winter and spring, consistent with models of the Martian atmospheric circulation, and the annular mode (EOF 3) is active only at the onset and demise of the baroclinic feature. When active, it is not uncommon for the annular mode to reside in either its positive or negative state stably for 20 to 30 sols. It is postulated that baroclinic waves with longitudinal wavenumber 2, 3, and 4 act as a pump for the annular mode. The annular mode should not be present in MGS TES data. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. CALTECH, Div Geol & Planetary Sci, Pasadena, CA 91125 USA. Geophys Fluid Dynam Lab, Princeton, NJ USA. RP Leroy, SS (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 20 TC 2 Z9 2 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 JUL 11 PY 2003 VL 30 IS 13 AR 1707 DI 10.1029/2002GL015909 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 704KJ UT WOS:000184338600001 ER PT J AU Pounds, KA Reeves, JN Page, KL Wynn, GA O'Brien, PT AF Pounds, KA Reeves, JN Page, KL Wynn, GA O'Brien, PT TI Fe K emission and absorption features in XMM-Newton spectra of Markarian 766: evidence for reprocessing in flare ejecta SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE galaxies : active; galaxies : general; galaxies : individual : Mrk 766; galaxies : Seyfert; X-rays : galaxies ID X-RAY-SPECTRUM; SEYFERT-1 GALAXY NGC-5548; ACTIVE GALACTIC NUCLEI; DUSTY WARM ABSORBER; BEPPOSAX OBSERVATION; ACCRETION DISK; ALPHA-EMISSION; BLACK-HOLE; IRON LINE; MCG-6-30-15 AB We report on the analysis of a long XMM-Newton European Photon Imaging Camera (EPIC) observation in 2001 May of the narrow-line Seyfert 1 galaxy Markarian 766 (Mrk 766). The 3-11 keV spectrum exhibits a moderately steep power-law continuum, with a broad emission line at similar to6.7 keV, probably blended with a narrow line at similar to6.4 keV, and a broad absorption trough above similar to8.7 keV. We identify both broad spectral features with reprocessing in He-like Fe. An earlier XMM-Newton observation of Mrk 766 in 2000 May, when the source was a factor similar to2 fainter, shows a similar broad emission line, but with a slightly flatter power law and absorption at a lower energy. In neither observation do we find a requirement for the previously reported broad 'red wing' to the line and hence of reflection from the innermost accretion disc. More detailed examination of the longer XMM-Newton observation reveals evidence for rapid spectral variability in the Fe K band, apparently linked with the occurrence of X-ray 'flares'. A reduction in the emission line strength and increased high-energy absorption during the X-ray flaring suggests that these transient effects are due to highly ionized ejecta associated with the flares. Simple scaling from the flare avalanche model proposed for the luminous quasi-stellar object PDS 456 confirms the feasibility of coherent flaring being the cause of the strong peaks seen in the X-ray light curve of Mrk 766. C1 Univ Leicester, Dept Phys & Astron, Leicester LE1 7RH, Leics, England. NASA, High Energy Astrophys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Pounds, KA (reprint author), Univ Leicester, Dept Phys & Astron, Leicester LE1 7RH, Leics, England. NR 40 TC 41 Z9 41 U1 0 U2 0 PU BLACKWELL PUBLISHING LTD PI OXFORD PA 9600 GARSINGTON RD, OXFORD OX4 2DG, OXON, ENGLAND SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD JUL 11 PY 2003 VL 342 IS 4 BP 1147 EP 1155 DI 10.1046/j.1365-8711.2003.06611.x PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 697VY UT WOS:000183965000018 ER PT J AU Dodelson, S Rozo, E Stebbins, A AF Dodelson, S Rozo, E Stebbins, A TI Primordial gravity waves and weak lensing SO PHYSICAL REVIEW LETTERS LA English DT Article ID MICROWAVE BACKGROUND-RADIATION; LARGE-SCALE STRUCTURE; INFLATIONARY UNIVERSE; GRAVITATIONAL-WAVES; MODES; MAPS AB Inflation produces a primordial spectrum of gravity waves in addition to the density perturbations which seed structure formation. We compute the signature of these gravity waves in the large scale shear field. The shear can be divided into a gradient mode (G or E) and a curl mode (C or B). The latter is produced only by gravity waves, so the observations of a nonzero curl mode could be seen as evidence for inflation. We find that the expected signal from inflation is small, peaking on the largest scales at l(l+1)C-l/2pi<10(-11) at l=2 and falling rapidly thereafter. Even for an all-sky deep survey, this signal would be below noise at all multipoles. C1 Fermilab Natl Accelerator Lab, NASA, Fermilab Astrophys Ctr, Batavia, IL 60510 USA. Univ Chicago, Dept Astron & Astrophys, Chicago, IL 60637 USA. Univ Chicago, Dept Phys, Chicago, IL 60637 USA. RP Dodelson, S (reprint author), Fermilab Natl Accelerator Lab, NASA, Fermilab Astrophys Ctr, POB 500, Batavia, IL 60510 USA. NR 31 TC 3 Z9 3 U1 0 U2 0 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 JUL 11 PY 2003 VL 91 IS 2 AR 021301 DI 10.1103/PhysRevLett.91.021301 PG 4 WC Physics, Multidisciplinary SC Physics GA 699YW UT WOS:000184086000004 ER PT J AU Souchkov, AB Simpson, JR Quijada, M Ishibashi, H Hur, N Ahn, JS Cheong, SW Millis, AJ Drew, HD AF Souchkov, AB Simpson, JR Quijada, M Ishibashi, H Hur, N Ahn, JS Cheong, SW Millis, AJ Drew, HD TI Exchange interaction effects on the optical properties of LuMnO3 SO PHYSICAL REVIEW LETTERS LA English DT Article ID HEXAGONAL YMNO3 AB We have measured the optical conductivity of single crystal LuMnO3 from 10 to 45 000 cm(-1) at temperatures between 4 and 300 K. A symmetry allowed on-site Mn d-d transition near 1.7 eV is observed to blueshift (similar to0.1 eV) in the antiferromagnetic state due to Mn-Mn superexchange interactions. Similar anomalies are observed in the temperature dependence of the TO phonon frequencies which arise from spin-phonon interaction. We find that the known anomaly in the temperature dependence of the quasistatic dielectric constant epsilon(0) below T(N)similar to90 K is overwhelmingly dominated by the phonon contributions. C1 Univ Maryland, Mat Res Sci & Engn Ctr, College Pk, MD 20742 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Rutgers State Univ, Dept Phys & Astron, Piscataway, NJ 08854 USA. Seoul Natl Univ, Ctr Strongly Correlated Mat Res, Seoul 151742, South Korea. Columbia Univ, Dept Phys, New York, NY 10027 USA. RP Univ Maryland, Mat Res Sci & Engn Ctr, College Pk, MD 20742 USA. RI Hur, Namjung/G-3752-2013 NR 13 TC 95 Z9 96 U1 1 U2 33 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 EI 1079-7114 J9 PHYS REV LETT JI Phys. Rev. Lett. PD JUL 11 PY 2003 VL 91 IS 2 AR 027203 DI 10.1103/PhysRevLett.91.027203 PG 4 WC Physics, Multidisciplinary SC Physics GA 699YW UT WOS:000184086000042 PM 12906506 ER PT J AU Mason, BS Pearson, TJ Readhead, ACS Shepherd, MC Sievers, J Udomprasert, PS Cartwright, JK Farmer, AJ Padin, S Myers, ST Bond, JR Contaldi, CR Pen, U Prunet, S Pogosyan, D Carlstrom, JE Kovac, J Leitch, EM Pryke, C Halverson, NW Holzapfel, WL Altamirano, P Bronfman, L Casassus, S May, J Joy, M AF Mason, BS Pearson, TJ Readhead, ACS Shepherd, MC Sievers, J Udomprasert, PS Cartwright, JK Farmer, AJ Padin, S Myers, ST Bond, JR Contaldi, CR Pen, U Prunet, S Pogosyan, D Carlstrom, JE Kovac, J Leitch, EM Pryke, C Halverson, NW Holzapfel, WL Altamirano, P Bronfman, L Casassus, S May, J Joy, M TI The anisotropy of the microwave background to l=3500: Deep field observations with the cosmic background imager SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmic microwave background; cosmology : observations ID ANGULAR POWER SPECTRUM; SMALL-SCALE FLUCTUATIONS; CASSIOPEIA-A; RADIATION; SIMULATIONS; UNIVERSE; MAPS; GHZ; CLUSTERS; ARRAY AB We report measurements of anisotropy in the cosmic microwave background radiation over the multipole range l similar to 200 3500 with the Cosmic Background Imager based on deep observations of three fields. These results confirm the drop in power with increasing l first reported in earlier measurements with this instrument and extend the observations of this decline in power out to l similar to 2000. The decline in power is consistent with the predicted damping of primary anisotropies. At larger multipoles, l = 2000 3500, the power is 3.1 sigma greater than standard models for intrinsic microwave background anisotropy in this multipole range and 3.5 sigma greater than zero. This excess power is not consistent with expected levels of residual radio source contamination but, for sigma(8)greater than or similar to1, is consistent with predicted levels of a secondary Sunyaev-Zeldovich anisotropy. Further observations are necessary to confirm the level of this excess and, if confirmed, determine its origin. C1 CALTECH, Owens Valley Radio Observ, Pasadena, CA 91125 USA. Natl Radio Astron Observ, Socorro, NM 87801 USA. Canadian Inst Theoret Astrophys, Toronto, ON M5S 3H8, Canada. Univ Alberta, Avadh Bhatia Phys Lab, Edmonton, AB T6G 2J1, Canada. Univ Chicago, Ctr Astron & Astrophys, Chicago, IL 60637 USA. Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Chile, Dept Astron, Santiago, Chile. NASA, George C Marshall Space Flight Ctr, Dept Space Sci, Huntsville, AL 35812 USA. RP Natl Radio Astron Observ, POB 2, Green Bank, WV 24944 USA. RI Bronfman, Leonardo/H-9544-2013; Holzapfel, William/I-4836-2015; Pearson, Timothy/N-2376-2015; Casassus, Simon/I-8609-2016; OI Bronfman, Leonardo/0000-0002-9574-8454; Pearson, Timothy/0000-0001-5213-6231; Sievers, Jonathan/0000-0001-6903-5074 NR 55 TC 260 Z9 261 U1 0 U2 1 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 JUL 10 PY 2003 VL 591 IS 2 BP 540 EP 555 DI 10.1086/375507 PN 1 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 698UF UT WOS:000184016700004 ER PT J AU Pearson, TJ Mason, BS Readhead, ACS Shepherd, MC Sievers, JL Udomprasert, PS Cartwright, JK Farmer, AJ Padin, S Myers, ST Bond, JR Contaldi, CR Pen, UL Prunet, S Pogosyan, D Carlstrom, JE Kovac, J Leitch, EM Pryke, C Halverson, NW Holzapfel, WL Altamirano, P Bronfman, L Casassus, S May, J Joy, M AF Pearson, TJ Mason, BS Readhead, ACS Shepherd, MC Sievers, JL Udomprasert, PS Cartwright, JK Farmer, AJ Padin, S Myers, ST Bond, JR Contaldi, CR Pen, UL Prunet, S Pogosyan, D Carlstrom, JE Kovac, J Leitch, EM Pryke, C Halverson, NW Holzapfel, WL Altamirano, P Bronfman, L Casassus, S May, J Joy, M TI The anisotropy of the microwave background to l=3500: Mosaic observations with the cosmic background imager SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmic microwave background; cosmology : observations; techniques : interferometric ID ANGULAR POWER SPECTRUM; INTERFEROMETER OBSERVATIONS; MULTIPLE PEAKS; FLUCTUATIONS; RADIATION AB Using the Cosmic Background Imager (CBI), a 13-element interferometer array operating in the 26 - 36 GHz frequency band, we have observed 40 deg(2) of sky in three pairs of fields, each similar to145' x 165', using overlapping pointings (mosaicking). We present images and power spectra of the cosmic microwave background radiation in these mosaic fields. We remove ground radiation and other low-level contaminating signals by differencing matched observations of the fields in each pair. The primary foreground contamination is due to point sources ( radio galaxies and quasars). We have subtracted the strongest sources from the data using higher resolution measurements, and we have projected out the response to other sources of known position in the power spectrum analysis. The images show features on scales similar to6' - 15', corresponding to masses similar to(5-80) x 10(14) M-. at the surface of last scattering, which are likely to be the seeds of clusters of galaxies. The power spectrum estimates have a resolution Deltal approximate to 200 and are consistent with earlier results in the multipole range l less than or similar to 1000. The power spectrum is detected with high signal-to-noise ratio in the range 300 less than or similar to l less than or similar to 1700. For 1700 less than or similar to l less than or similar to 3000 the observations are consistent with the results from more sensitive CBI deep field observations. The results agree with the extrapolation of cosmological models fitted to observations at lower l and show the predicted drop at high l (the "damping tail"). C1 CALTECH, Owens Valley Radio Observ, Pasadena, CA 91125 USA. Natl Radio Astron Observ, Socorro, NM 87801 USA. Univ Toronto, Canadian Inst Theoret Astrophys, Toronto, ON M5S 3H8, Canada. Univ Alberta, Dept Phys, Edmonton, AB T6G 2J1, Canada. Univ Chicago, Dept Astron & Astrophys, Chicago, IL 60637 USA. Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Univ Chile, Dept Astron, Santiago, Chile. NASA, George C Marshall Space Flight Ctr, Dept Space Sci, Huntsville, AL 35812 USA. RP Pearson, TJ (reprint author), CALTECH, Owens Valley Radio Observ, 1200 E Calif Blvd, Pasadena, CA 91125 USA. RI Bronfman, Leonardo/H-9544-2013; Holzapfel, William/I-4836-2015; Pearson, Timothy/N-2376-2015; Casassus, Simon/I-8609-2016 OI Sievers, Jonathan/0000-0001-6903-5074; Bronfman, Leonardo/0000-0002-9574-8454; Pearson, Timothy/0000-0001-5213-6231; NR 28 TC 254 Z9 255 U1 0 U2 1 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 JUL 10 PY 2003 VL 591 IS 2 BP 556 EP 574 DI 10.1086/375508 PN 1 PG 19 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 698UF UT WOS:000184016700005 ER PT J AU Otte, B Murphy, EM Howk, JC Wang, QD Oegerle, WR Sembach, KR AF Otte, B Murphy, EM Howk, JC Wang, QD Oegerle, WR Sembach, KR TI Probing OVI emission in the halos of edge-on spiral galaxies SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : general; galaxies : halos; galaxies : individual (NGC 4631; NGC 891); galaxies : ISM; ISM : general; ISM : individual (NGC 4631; NGC 891) ID DIFFUSE HOT GAS; MULTIPHASE HALO; GALACTIC HALO; IONIZED-GAS; NGC 891; NGC-4631; NGC-891; VI; HYDROGEN; CORONA AB We have used the Far Ultraviolet Spectroscopic Explorer to search for O VI lambdalambda1031.926, 1037.617 emission in the halos of the edge-on spiral galaxies NGC 4631 and NGC 891. In NGC 4631, we detected O vi in emission toward a soft X-ray bubble above a region containing numerous Halpha arcs and filaments. The line-of-sight component of the motion of the O vi gas appears to match the underlying disk rotation. The observed O vi luminosities can account for 0.2% - 2% of the total energy input from supernovae (assuming a full O vi emitting halo) and yield mass flux cooling rates between 0.48 and 2.8 M-. yr(-1) depending on the model used in the derivations. On the basis of these findings, we believe it is likely that we are seeing cooling, galactic fountain gas. No emission was detected from the halo of NGC 891, a galaxy in a direction with considerably high foreground Galactic extinction. C1 Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. Univ Virginia, Dept Astron, Charlottesville, VA 22903 USA. Univ Calif San Diego, Ctr Astrophys & Space Sci, La Jolla, CA 92093 USA. Univ Massachusetts, Dept Astron, Amherst, MA 01003 USA. NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. Space Telescope Sci Inst, Baltimore, MD 21218 USA. RP Otte, B (reprint author), Johns Hopkins Univ, Dept Phys & Astron, 3400 N Charles St, Baltimore, MD 21218 USA. RI Oegerle, William/C-9070-2012; Howk, Jay/D-2577-2013; OI Howk, J. Christopher/0000-0002-2591-3792; Murphy, Edward/0000-0003-2925-738X NR 27 TC 18 Z9 18 U1 0 U2 1 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 JUL 10 PY 2003 VL 591 IS 2 BP 821 EP 826 DI 10.1086/375535 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 698UF UT WOS:000184016700022 ER PT J AU Dorman, B O'Connell, RW Rood, RT AF Dorman, B O'Connell, RW Rood, RT TI Age and abundance discrimination in old stellar populations using mid-ultraviolet colors SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : evolution; galaxies : stellar content; ultraviolet : galaxies ID EARLY-TYPE GALAXIES; EXTREMELY RED GALAXIES; HUBBLE DEEP FIELD; ELLIPTIC GALAXIES; SPECTRAL-SYNTHESIS; DISTANT CLUSTERS; INTEGRATED SPECTRA; STAR-FORMATION; LBDS 53W091; 47 TUCANAE AB The rest-frame mid-ultraviolet spectral region (2000 - 3200 Angstrom) is important in analyzing the stellar populations of the "red envelope'' systems observed at high redshifts. Here we explore the usefulness of the mid-UV for determining ages and abundances of old populations. We work with a theoretical set of low-resolution spectra and broadband colors because tests show that these are at present more realistic than high-resolution models. A mid-UV to optical/IR wavelength baseline provides good separation of population components because the main-sequence turnoff dominates the integrated light between 2500 and 4000 Angstrom. Mid-UV spectral features are not sensitive to the dwarf/giant mixture in the population, unlike those in the optical region. We find a 6 mag difference in the mid-UV continuum level (normalized at V) over the metallicity range -1.5 < log(Z/Z(.)) < +0.5 and a comparable difference (per unit log t) for ages in the range 4 - 16 Gyr. Logarithmic derivatives of mid-UV colors with respect to age or metal abundance are 3 - 10 times larger than for the UBV region. Most of the spectral information on old populations therefore resides below 4000 Angstrom. Measurement of a single mid-UV color is capable of placing a strong lower bound on the mean metallicity of an old population. We investigate the capability of UBV and mid-UV broadband colors to separately determine age and abundance, taking into account precision in the color measurements. We find that the mid-UV improves resolution in log t, log Z space by about a factor of 3 for a given observational precision. Contamination by hot, post - He. ash evolutionary phases can seriously affect the mid-UV spectra of old populations. A simple estimate shows that contamination can reach over 80% in some cases. However, this is straightforward to remove as long as far-UV measurements are available. We find that extinction should have relatively small effects on parameters derived for old populations from the mid-UV. Finally, we show that a 4 Gyr, solar abundance model based on empirical spectra for nearby stars provides an excellent. t to the mid-UV spectrum of the Local Group elliptical galaxy M32. This indicates that the poorer results obtained from theoretical spectra do arise from limitations of the synthesis models for individual stars. C1 Univ Virginia, Dept Astron, Charlottesville, VA 22903 USA. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Univ Virginia, Dept Astron, POB 3818, Charlottesville, VA 22903 USA. EM ben.dorman@gsfc.nasa.gov; rwo@virginia.edu; rtr@virginia.edu NR 74 TC 34 Z9 34 U1 0 U2 1 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 JUL 10 PY 2003 VL 591 IS 2 BP 878 EP 890 DI 10.1086/375413 PN 1 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 698UF UT WOS:000184016700026 ER PT J AU Baganoff, FK Maeda, Y Morris, M Bautz, MW Brandt, WN Cui, W Doty, JP Feigelson, ED Garmire, GP Pravdo, SH Ricker, GR Townsley, LK AF Baganoff, FK Maeda, Y Morris, M Bautz, MW Brandt, WN Cui, W Doty, JP Feigelson, ED Garmire, GP Pravdo, SH Ricker, GR Townsley, LK TI Chandra X-ray spectroscopic imaging of Sagittarius A* and the central parsec of the Galaxy SO ASTROPHYSICAL JOURNAL LA English DT Review DE accretion, accretion disks; black hole physics; galaxies : active; Galaxy : center; X-rays : ISM; X-rays : stars ID SUPERMASSIVE BLACK-HOLE; DOMINATED ACCRETION FLOWS; GALACTIC-CENTER REGION; SGR-A; LINEAR-POLARIZATION; MILKY-WAY; CIRCULAR-POLARIZATION; PROPER-MOTION; REFLECTION-NEBULA; RADIO VARIABILITY AB We report the results of the first-epoch observation with the ACIS-I instrument on the Chandra X-Ray Observatory of Sagittarius A* (Sgr A*), the compact radio source associated with the supermassive black hole (SMBH) at the dynamical center of the Milky Way. This observation produced the first X-ray (0.5-7 keV) spectroscopic image with arcsecond resolution of the central 17' x 17' (40 pc x 40 pc) of the Galaxy. We report the discovery of an X-ray source, CXOGC J174540.0 - 290027, coincident with Sgr A* within 0."27 +/- 0."18. The probability of a false match is estimated to be less than or similar to 0.5%. The spectrum is well fitted either by an absorbed power law with photon index Gamma approximate to 2.7 or by an absorbed optically thin thermal plasma with kT approximate to 1.9 keV and column density N-H approximate to 1 x 10(23) cm(-2). The observed flux in the 2 - 10 keV band is approximate to 1.3 x 10(-13) ergs cm(-2) s(-1), and the absorption-corrected luminosity is approximate to2.4 x 10(33) ergs s(-1). The X-ray emission at the position of Sgr A* is extended, with an intrinsic size of approximate to1."4 (FWHM), consistent with the Bondi accretion radius for a 2.6 x 10(6) M. black hole. A compact component within the source flared by up to a factor of 3 over a period of approximate to1 hr at the start of the observation. The search for Kalpha line emission from iron was inconclusive, yielding an upper limit on the equivalent width of 2.2 keV. Several potential stellar origins for the X-ray emission at Sgr A* are considered, but we conclude that the various properties of the source favor accretion onto the SMBH as the origin for the bulk of the emission. These data are inconsistent with "standard'' advection-dominated accretion flow (ADAF) models or Bondi models, unless the accretion rate from stellar winds is much lower than anticipated. The central parsec of the Galaxy contains an approximate to1.3 keV plasma with electron density n(e) approximate to 26(etaf)(1/2) cm(-3), where eta(f) is the filling factor. This plasma should supply approximate to 10(-6) M. yr(-1) of material to the accretion flow at the Bondi radius, whereas measurements of linear polarization at 150 GHz and above limit the accretion rate near the event horizon to less than or similar to 10(-8) M. yr(-1), assuming an equipartition magnetic field. Taken together, the X-ray and radio results imply that outflows or convection are playing a role in ADAF models and subequipartition magnetic fields in Bondi models, or else the X-ray emission must be generated predominantly via the synchrotron self-Compton (SSC) process. The measured extent of the source and the detection of short timescale variability are evidence that the emission from Sgr A* contains both thermal and nonthermal emission components at comparable levels. We also discuss the complex structure of the X-ray emission from the Sgr A radio complex and along the Galactic plane. Morphological evidence is presented that Sgr A* and the H II region Sgr A West lie within the hot plasma in the central cavity of Sgr A East, which we interpret as a supernova remnant that may have passed through the position of the SMBH, leading to a period of increased activity that ended within the past approximate to300 yr. Similarly, we have discovered bright clumps of X-ray emission located on opposite sides of the Galactic plane, along a line passing through the central parsec of the Galaxy. The arrangement of these lobes suggests that Sgr A* may have experienced an earlier period of increased activity lasting several thousand years during which it expelled hot gas in a bipolar outflow oriented roughly perpendicular to the Galactic plane. Additionally, we present an analysis of stellar emission within the central parsec of the Galaxy. C1 MIT, Ctr Space Res, Cambridge, MA 02139 USA. Inst Space & Astronaut Sci, Sagamihara, Kanagawa 2298501, Japan. Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA 90095 USA. Penn State Univ, Dept Astron & Astrophys, University Pk, PA 16802 USA. Purdue Univ, Dept Phys, W Lafayette, IN 47907 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Baganoff, FK (reprint author), MIT, Ctr Space Res, Cambridge, MA 02139 USA. RI Brandt, William/N-2844-2015; OI Brandt, William/0000-0002-0167-2453; Cui, Wei/0000-0002-6324-5772 NR 143 TC 447 Z9 449 U1 1 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 JUL 10 PY 2003 VL 591 IS 2 BP 891 EP 915 DI 10.1086/375145 PN 1 PG 25 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 698UF UT WOS:000184016700027 ER PT J AU Shenoy, SS Whittet, DCB Chiar, JE Adamson, AJ Roberge, WG Hassel, GE AF Shenoy, SS Whittet, DCB Chiar, JE Adamson, AJ Roberge, WG Hassel, GE TI A test case for the organic refractory model of interstellar dust SO ASTROPHYSICAL JOURNAL LA English DT Article DE astrochemistry; dust, extinction; infrared : ISM; ISM : lines and bands; ISM : molecules; stars : individual (Elias 25) ID OPHIUCHUS DARK-CLOUD; YOUNG STELLAR OBJECTS; H2O ICE BANDS; INFRARED-SPECTROSCOPY; RHO-OPHIUCHI; CARBON GRAINS; SPECTROPOLARIMETRIC CONSTRAINTS; ABSORPTION FEATURES; PROTOSTAR ELIAS-29; 3-MICRON SPECTRA AB The organic refractory model of interstellar dust postulates that the grains primarily responsible for visual extinction consist of silicate cores coated with organic refractory matter (ORM) supposed to form by photochemical processing of ice mantles. We identify the line of sight to the early-type star Elias 25, in the rho Oph dark cloud, as a test for local production of ORM in an environment where mantled grains are exposed to a substantial ultraviolet radiation field. Infrared spectra of Elias 25 in the 2.4 - 4.0 mum region were used to examine the 3 mum ice profile and to search for the C-H bond absorption feature near 3.4 mum that occurs in laboratory-synthesized ORM. We find that the ice feature in Elias 25 has an unusually deep 3.1 - 3.7 mum wing, but no detectable 3.4 mum feature is present in the wing profile. An upper limit on the tau(3.4)/A(V) ratio is set that is a factor of 4 lower than that determined from the feature detected in the diffuse interstellar medium toward Cygnus OB2 No. 12. Our results are consistent with other evidence indicating that the carrier of the 3.4 mum feature is destroyed, rather than produced, inside dense clouds. C1 Rensselaer Polytech Inst, Dept Phys Appl Phys & Astron, Troy, NY 12180 USA. Rensselaer Polytech Inst, New York Ctr Studies Origins Life, Troy, NY 12180 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. SETI Inst, Mountain View, CA 94043 USA. Joint Astron Ctr, Hilo, HI 96720 USA. RP Shenoy, SS (reprint author), Rensselaer Polytech Inst, Dept Phys Appl Phys & Astron, Troy, NY 12180 USA. OI Whittet, Douglas/0000-0001-8539-3891; adamson, andrew/0000-0003-1120-5178 NR 41 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 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUL 10 PY 2003 VL 591 IS 2 BP 962 EP 967 DI 10.1086/375416 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 698UF UT WOS:000184016700032 ER PT J AU Federman, SR Lambert, DL Sheffer, Y Cardelli, JA Andersson, BG van Dishoeck, EF Zsargo, J AF Federman, SR Lambert, DL Sheffer, Y Cardelli, JA Andersson, BG van Dishoeck, EF Zsargo, J TI Further evidence for chemical fractionation from ultraviolet observations of carbon monoxide SO ASTROPHYSICAL JOURNAL LA English DT Review DE astrochemistry; ISM : abundances; ISM : molecules; stars : individual (rho Ophiuchi A; chi Ophiuchi) ID DIFFUSE INTERSTELLAR CLOUDS; BAND OSCILLATOR-STRENGTHS; HIGH-RESOLUTION SPECTROGRAPH; HUBBLE-SPACE-TELESCOPE; EXCITED HYDROGEN MOLECULES; INTER-STELLAR CLOUDS; ZETA-OPHIUCHI; INTERSYSTEM TRANSITIONS; ATOMIC PHYSICS; RHO-OPHIUCHI AB Ultraviolet absorption from interstellar (CO)-C-12 and (CO)-C-13 was detected toward rho Oph A and chi Oph. The measurements were obtained at medium resolution with the Goddard High Resolution Spectrograph on the Hubble Space Telescope. Column density ratios, N((CO)-C-12)/ N((CO)-C-13), of 125 +/- 23 and 117 +/- 35 were derived for the sight lines toward rho Oph A and chi Oph, respectively. A value of 1100 +/- 600 for the ratio N((CO)-C-12-O-16)/ N((CO)-C-12-O-18) toward rho Oph A was also obtained. Absorption from vibrationally excited H-2 (v" = 3) was clearly seen toward this star as well. The ratios are larger than the isotopic ratios for carbon and oxygen appropriate for ambient interstellar material. Since for both carbon and oxygen the more abundant isotopomer is enhanced, selective isotopic photodissociation plays the key role in the fractionation process for these directions. The enhancement arises because the more abundant isotopomer has lines that are more optically thick, resulting in more self-shielding from dissociating radiation. A simple argument involving the amount of self-shielding [from N((CO)-C-12)] and the strength of the ultraviolet radiation field permeating the gas ( from the amount of vibrationally excited H-2) shows that selective isotopic photodissociation controls the fractionation seen in these two sight lines, as well as the sight line to zeta Oph. C1 Univ Toledo, Dept Phys & Astron, Toledo, OH 43606 USA. Univ Texas, Dept Astron, Austin, TX 78712 USA. Villanova Univ, Dept Astron & Astrophys, Villanova, PA 19085 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. Sterrewacht Leiden, NL-2300 RA Leiden, Netherlands. RP Federman, SR (reprint author), Univ Toledo, Dept Phys & Astron, Toledo, OH 43606 USA. OI Andersson, B-G/0000-0001-6717-0686 NR 110 TC 37 Z9 37 U1 1 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 JUL 10 PY 2003 VL 591 IS 2 BP 986 EP 999 DI 10.1086/375483 PN 1 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 698UF UT WOS:000184016700034 ER PT J AU Barsony, M Koresko, C Matthews, K AF Barsony, M Koresko, C Matthews, K TI A search for close binaries in the rho Ophiuchi star-forming region SO ASTROPHYSICAL JOURNAL LA English DT Article DE binaries : close; infrared : stars; stars : pre-main-sequence; techniques : high angular resolution ID T-TAURI STARS; X-RAY SOURCES; IMAGING SURVEY; DARK CLOUD; TRAPEZIUM CLUSTER; EMBEDDED-CLUSTER; YOUNG BINARIES; MULTIPLICITY; PROTOSTARS; LUMINOSITY AB We have carried out a new, near-infrared speckle imaging survey of 19 members of the young stellar population in the nearby (d = 140 pc) rho Oph cloud core. Results for four binary and one newly discovered triple system are reported. Data for all known multiple systems among the pre-main-sequence population of rho Oph are tabulated. We define a restricted binary fraction, F-b; r, and a restricted companion fraction, F-c; r, as counting only those systems most detectable in the present and previous high-resolution near-infrared imaging surveys having separations between 0."1 and similar to1."1 and K-band magnitude differences DeltaK < 3. Analysis of all the available multiplicity data results in updated values of F-b; r = 24% +/- 11% and F-c; r = 24% +/- 11% for the Ophiuchus pre-main-sequence population. These values are consistent with the values in the Taurus star-forming region, and F-c; r is in excess by a factor of 2 relative to the main sequence at the 1 σ level. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. CALTECH, Michelson Sci Ctr, Pasadena, CA 91125 USA. CALTECH, Opt Observ, Pasadena, CA 91125 USA. RP Barsony, M (reprint author), CALTECH, Jet Prop Lab, Mail Stop 169-327,4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 44 TC 28 Z9 28 U1 0 U2 1 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 JUL 10 PY 2003 VL 591 IS 2 BP 1064 EP 1074 DI 10.1086/375532 PN 1 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 698UF UT WOS:000184016700040 ER PT J AU Prieto, CA Hubeny, I Lambert, DL AF Prieto, CA Hubeny, I Lambert, DL TI Non-LTE model atmospheres for late-type stars. II. Restricted non-LTE calculations for a solar-like atmosphere SO ASTROPHYSICAL JOURNAL LA English DT Article DE line : formation; radiative transfer; stars : atmospheres; Sun : abundances; Sun : UV radiation ID IRRADIANCE COMPARISON EXPERIMENT-1; STELLAR ATMOSPHERES; ULTRAVIOLET CONTINUUM; LINE FORMATION; BERYLLIUM ABUNDANCES; CONTINUOUS OPACITY; RADIATIVE OPACITY; DWARF STARS; RADIUS; OXYGEN AB We test our knowledge of the atomic opacity in the solar UV spectrum. Using the atomic data compiled in the first paper in this series from modern, publicly available databases, we perform calculations that are compared with space-based observations of the Sun. At wavelengths longer than about 2600 Angstrom, LTE modeling can reproduce quite closely the observed fluxes; uncertainties in the atomic line data account fully for the differences between calculated and observed fluxes. At shorter wavelengths, departures from LTE appear to be important, since our LTE and restricted non-LTE calculations differ. Analysis of visible/near-IR Na I and O I lines, two species that produce a negligible absorption in the UV, shows that observed departures from LTE for these species can be reproduced very accurately with restricted (fixed atmospheric structure) non-LTE calculations. C1 Univ Texas, McDonald Observ, Austin, TX 78712 USA. Univ Texas, Dept Astron, Austin, TX 78712 USA. NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. RP Prieto, CA (reprint author), Univ Texas, McDonald Observ, Austin, TX 78712 USA. NR 66 TC 19 Z9 19 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 JUL 10 PY 2003 VL 591 IS 2 BP 1192 EP 1202 PN 1 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 698UF UT WOS:000184016700051 ER PT J AU Heike, K Awaki, H Misao, Y Hayashida, K Weaver, KA AF Heike, K Awaki, H Misao, Y Hayashida, K Weaver, KA TI Discovery of bright variable X-ray sources in NGC 1569 with Chandra SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : individual (NGC 1569); galaxies : starburst ID STARBURST GALAXY M82; ASCA; BINARIES; NGC-253 AB From the analysis of a similar to100 ks Chandra observation of the dwarf starburst galaxy NGC 1569, we have found that the X-ray point sources CXOU 043048.1 + 645050 and CXOU 043048.6 + 645058 show significant time variability. During this observation, the X-ray flux of CXOU 043048.1 + 645050 increased by 10 times in only 2 x 10(4) s. Since the spectrum in its bright phase was fitted with a disk blackbody model with kT(m) approximate to 0.43 keV and the bolometric luminosity is L-bol approximate to 10(38) ergs s(-1), this source is an X-ray binary with a stellar mass black hole. Since the spectrum in its faint phase was also fitted with a disk blackbody model, the time variability can be explained by a change of the accretion rate onto the black hole. The other variable source, CXOU 043048.6+645058, had a flat spectrum with a photon index of similar to1.6. This source may be an X-ray binary with an X-ray luminosity of several times 10(37) ergs s(-1). In addition, three other weak sources showed possible time variability. Taking all of the variability into account may suggest an abundant population of compact X-ray sources in NGC 1569. C1 Ehime Univ, Fac Sci, Dept Phys, Matsuyama, Ehime 7908577, Japan. Osaka Univ, Fac Sci, Dept Astrophys, Toyonaka, Osaka 5600043, Japan. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Heike, K (reprint author), Ehime Univ, Fac Sci, Dept Phys, Matsuyama, Ehime 7908577, Japan. NR 18 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 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUL 10 PY 2003 VL 591 IS 2 BP L99 EP L102 DI 10.1086/377090 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 698UJ UT WOS:000184017100007 ER PT J AU Bauschlicher, CW Ricca, A AF Bauschlicher, CW Ricca, A TI Do individual molecule rotational barriers explain the retention times of molecular memories? SO CHEMICAL PHYSICS LETTERS LA English DT Article AB We compute the rotational barriers for two molecules for which experimental memory retention times exist. The computed barriers for the neutral molecules and the cations do not explain the observed experimental results, but the anion barriers are consistent with the observations. The implications of this are discussed. (C) 2003 Elsevier Science B.V. All rights reserved. C1 NASA, Ames Res Ctr, Space Technol Div, Moffett Field, CA 94035 USA. RP Bauschlicher, CW (reprint author), NASA, Ames Res Ctr, Space Technol Div, Mail Stop 230-3, Moffett Field, CA 94035 USA. NR 8 TC 8 Z9 8 U1 0 U2 0 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 JUL 10 PY 2003 VL 375 IS 5-6 BP 459 EP 462 DI 10.1016/S0009-2614(03)00887-X PG 4 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 699ZB UT WOS:000184086600003 ER PT J AU McKay, CP Hand, KP Doran, PT Andersen, DT Priscu, JC AF McKay, CP Hand, KP Doran, PT Andersen, DT Priscu, JC TI Clathrate formation and the fate of noble and biologically useful gases in Lake Vostok, Antarctica SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID SUBGLACIAL LAKES; ICE-SHEET; WATER; SUPERSATURATION; FROZEN; LIFE AB [1] Lake Vostok is a large lake located 4 km beneath the East Antarctic Ice Sheet that should be supersaturated with dissolved gases in equilibrium with clathrate present in the water column. Here we show that if the age of the lake is such that the lake water mass has been cycled over 30 times then the total dissolved gas equilibrates at about 2.5 liters (STP) of gas per kg of water; high enough to have important implications for drilling into this deep subglacial lake. Different air gases are preferentially incorporated into the clathrate and thus the molar ratios in the water column will reflect the presence of clathrate and indicate a more precise age of the lake. Preferential incorporation of CO2 into the clathrate would result in the clathrate sinking if the carbon input is 1% of the air input and the lake water is fresh water. The redox state of the lake is set by the high oxygen concentration which is 50 times more than air-equilibrated water and may be a severe biological stress. C1 NASA, Div Space Sci, Ames Res Ctr, Moffett Field, CA 94035 USA. Stanford Univ, Dept Geol & Environm Sci, Stanford, CA 94305 USA. Univ Illinois, Dept Earth & Environm Sci, Chicago, IL 60607 USA. SETI Inst, Ctr Study Life Universe, Mountain View, CA 94043 USA. Montana State Univ, Dept Land Resources & Environm Sci, Bozeman, MT 59717 USA. RP McKay, CP (reprint author), NASA, Div Space Sci, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 31 TC 23 Z9 24 U1 0 U2 7 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 JUL 10 PY 2003 VL 30 IS 13 AR 1702 DI 10.1029/2003GL017490 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 704KH UT WOS:000184338500005 ER PT J AU Peterson, DL Brass, JA Smith, WH Langford, G Wegener, S Dunagan, S Hammer, P Snook, K AF Peterson, DL Brass, JA Smith, WH Langford, G Wegener, S Dunagan, S Hammer, P Snook, K TI Platform options of free-flying satellites, UAVs or the International Space Station for remote sensing assessment of the littoral zone SO INTERNATIONAL JOURNAL OF REMOTE SENSING LA English DT Article; Proceedings Paper CT Meeting on the Remote Sensing of the Marine Littoral Environment CY DEC 15-16, 1999 CL LONDON, ENGLAND SP Linnean Soc ID ARRAY SCANNED INTERFEROMETER; SYSTEM DESCRIPTION; CORAL-REEFS; IMAGERY; ENVIRONMENTS; PROJECT AB Over the years, making or creating a choice for a specific platform from which to conduct remote sensing observations of specific targets brings in many factors related to the target characteristics and how the data are going to be used. Attempts to measure Earth's diverse objects have generated a wide range of platform alternatives, from geostationary satellites to low-flying aircraft. Now several additional options possessing unique attributes are available: the International Space Station (ISS) and Un-inhabited Aerial Vehicles (UAVs). This paper explores some of the tradeoffs among these alternatives for the special problem of remotely sensing the littoral zone, but especially the shallow ecosystems. Though the surface area of the littoral zone is relatively large, it is geographically disbursed and somewhat linear. Also, the spatial, spectral and temporal variability of ecosystems in this zone is very high, and signals are masked by the overlying water column. Ideally, a frequent revisit time would be desirable to monitor their health and changing condition. These characteristics place important constraints on platform choice as one tries to design a system to monitor these critical ecosystems and provide useful information for managing them. This paper discusses these tradeoff issues as offered mainly by three platform choices: free-flying satellites, ISS, UAVs and other aircraft. C1 NASA, Ames Res Ctr, Div Earth Sci, Moffett Field, CA 94035 USA. Washington Univ, St Louis, MO USA. ITV Corp, Mountain View, CA 94040 USA. NASA, Ames Res Ctr, Space Projects Div, Moffett Field, CA 94035 USA. RP Peterson, DL (reprint author), NASA, Ames Res Ctr, Div Earth Sci, Moffett Field, CA 94035 USA. NR 31 TC 4 Z9 4 U1 0 U2 6 PU TAYLOR & FRANCIS LTD PI ABINGDON PA 4 PARK SQUARE, MILTON PARK, ABINGDON OX14 4RN, OXON, ENGLAND SN 0143-1161 J9 INT J REMOTE SENS JI Int. J. Remote Sens. PD JUL 10 PY 2003 VL 24 IS 13 BP 2785 EP 2804 DI 10.1080/0143116031000066963 PG 20 WC Remote Sensing; Imaging Science & Photographic Technology SC Remote Sensing; Imaging Science & Photographic Technology GA 698NP UT WOS:000184005900013 ER PT J AU Gao, BC Kaufman, YJ AF Gao, BC Kaufman, YJ TI Water vapor retrievals using moderate resolution Imaging spectroradiometer (MODIS) near-infrared channels SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE water vapor; remote sensing; MODIS; terrestrial atmosphere ID DIFFERENTIAL ABSORPTION; SPECTROMETER AVIRIS; PRECIPITABLE WATER; RADIATIVE-TRANSFER; INSTRUMENT; SCATTERING; ALGORITHM; AEROSOL; CLOUDS; EARTH AB [1] At present, two Moderate Resolution Imaging Spectroradiometer (MODIS) instruments on board the NASA Terra and Aqua Spacecraft platforms are operational for global remote sensing of the land, ocean, and atmosphere. In this paper, we describe an algorithm for water vapor derivations using several MODIS near-IR channels. The derivations are made over areas that have reflective surfaces in the near-IR, such as clear land areas, clouds, and oceanic areas with Sun glint. The algorithm relies on observations of water vapor attenuation of near-IR solar radiation reflected by surfaces and clouds. Techniques employing ratios of water vapor absorbing channels centered near 0.905, 0.936, and 0.940 mm with atmospheric window channels at 0.865 and 1.24 mm are used. The ratios partially remove the effects of variation of surface reflectance with wavelengths and result in the atmospheric water vapor transmittances. The column water vapor amounts are derived from the transmittances based on theoretical calculations and using lookup table procedures. Typical errors in the derived water vapor values are in the range between 5% and 10%. The daily "pixel-based'' near-IR water vapor product, which is a standard MODIS level 2 data product, at the 1-km spatial resolution of the MODIS instrument, and the daily, 8-day, and monthly near-IR water vapor products, which are standard MODIS level 3 products, at a 1degrees by 1degrees latitude-longitude grid globally are now routinely produced at a NASA computing facility. We present samples of water vapor images and comparisons to ground-based measurements by microwave radiometers. C1 USN, Remote Sensing Div, Res Lab, Washington, DC 20375 USA. NASA, Climate & Radiat Branch, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Gao, BC (reprint author), USN, Remote Sensing Div, Res Lab, Code 7212,4555 Overlook Ave SW, Washington, DC 20375 USA. EM gao@nrl.navy.mil NR 33 TC 175 Z9 187 U1 3 U2 35 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 JUL 10 PY 2003 VL 108 IS D13 AR 4389 DI 10.1029/2002JD003023 PG 10 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 704KP UT WOS:000184339100003 ER PT J AU Kim, EJ England, AW AF Kim, EJ England, AW TI A yearlong comparison of plot-scale and satellite footprint-scale 19 and 37 GHz brightness of the Alaskan North Slope SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE remote sensing; microwaves; radiometry; Arctic; tundra; land surface ID ARCTIC TUNDRA; AIR-TEMPERATURE; RADIOMETER DATA; CLIMATE; PERMAFROST; MODEL; CO2 AB [1] Subpixel heterogeneity remains a key issue in the estimation of land parameters using satellite passive microwave sensors; the scales of spatial variability on land are typically much smaller than sensor footprints (tens of km). Disaggregation is a necessary component of any successful assimilation or retrieval scheme attempting to exploit satellite passive microwave observations to estimate parameters at the local scale. This paper quantifies the similarity between ground-based brightness and satellite brightness observations at 19 and 37 GHz for Arctic tundra on the North Slope of Alaska, identifying and quantifying sources of the differences. To the extent that this very homogeneous area represents a limiting case, the impact of subpixel heterogeneity in less homogeneous areas may be gauged. The ground-based radiobrightness observations were collected during the Radiobrightness Energy Balance Experiment 3 (REBEX-3) conducted on the North Slope in 1994-1995. A comparison was made of 381 days of brightness observations from a tower-mounted Special Sensor Microwave Imager (SSM/I) simulator representing the full range of annual conditions with coincident satellite SSM/I observations. Issues such as instrument stability, the effects of atmospheric radiative transfer, and consistency of satellite pixel locations are considered. Linear correlations between tower-based and SSM/I brightness observations of 0.93, 0.94, 0.93, and 0.92 were observed for the 19V, 19H, 37V, and 37H channels, respectively. Footprint sizes were 2 x 4 m for the tower-based observations and 43 x 69 km for the resampled SSM/I observations. Atmospheric, topographic, and time-of-observation effects can account for the differences between the best fit lines and the 1:1 lines, with calibration errors accounting for the residual differences. C1 NASA, Lab Hydrospher Proc, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Michigan, Dept Atmospher Ocean & Space Sci, EECS 3120, Ann Arbor, MI 48109 USA. Univ Michigan, Dept Elect Engn & Comp Sci, Ann Arbor, MI 48109 USA. RP NASA, Lab Hydrospher Proc, Goddard Space Flight Ctr, Code 975, Greenbelt, MD 20771 USA. EM Ed.Kim@nasa.gov; england@umich.edu NR 50 TC 7 Z9 7 U1 0 U2 0 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 JUL 10 PY 2003 VL 108 IS D13 AR 4388 DI 10.1029/2002JD002393 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 704KP UT WOS:000184339100001 ER PT J AU Ziemke, JR Chandra, S Bhartia, PK AF Ziemke, JR Chandra, S Bhartia, PK TI Upper tropospheric ozone derived from the cloud slicing technique: Implications for large-scale convection SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE cloud slicing; tropospheric ozone; STE; THIR ID MODIFIED-RESIDUAL METHOD; 1997-1998 EL-NINO; STRATOSPHERIC OZONE; TOMS MEASUREMENTS; GLOBAL-MODEL; WATER-VAPOR; TROPOPAUSE; EXCHANGE; CHEMISTRY; CLIMATOLOGY AB [1] This study evaluates the spatial distributions and seasonal cycles in upper tropospheric ozone (pressure range 200-500 hPa) from low to high latitudes (60degreesS to 60degreesN) derived from the satellite retrieval method called "cloud slicing.'' The cloud slicing method determines ozone profile information in the troposphere by combining colocated measurements of cloud top pressure and above-cloud column ozone. Measurements of Nimbus 7 Total Ozone Mapping Spectrometer (TOMS) above-cloud column ozone and Nimbus 7 Temperature Humidity Infrared Radiometer (THIR) cloud top pressure during 1979-1984 were merged to derive upper tropospheric ozone. Because of large footprint measurements from TOMS (similar to100 km diameter on average), upper tropospheric ozone derived from cloud slicing coincides with large-scale convection events. These events are not necessarily representative of average atmospheric conditions in regions near and poleward of the tropospheric wind jets (around +/-30degrees latitude), especially in winter and spring seasons when dynamical wave activity in the troposphere and lower stratosphere is most intense. The cloud slicing method with Nimbus 7 geometry in any case provides a unique opportunity to investigate the behavior of upper tropospheric ozone under condition of intense broad-scale convection. In the tropics the measured upper tropospheric ozone shows year-round enhancement in the Atlantic region and evidence of a possible semiannual variability. Outside the tropics, upper tropospheric ozone from cloud slicing shows greatest abundance in winter and spring seasons in both hemispheres with largest variance and largest amounts in the northern hemisphere. This seasonal cycle behavior under conditions of intense convection is different from general ozonesonde climatology which shows instead upper tropospheric ozone maximizing around early to middle summer months. The seasonal cycles and spatial characteristics in upper tropospheric ozone from cloud slicing are similar to lower stratospheric ozone. It is suggested that the large-scale convection events with cloud slicing coincide with an occurrence of stratosphere-troposphere exchange (STE). C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Maryland Baltimore Cty, Goddard Earth Sci & Technol Ctr, Baltimore, MD 21228 USA. RP Ziemke, JR (reprint author), NASA, Goddard Space Flight Ctr, Code 916,Bldg 33,Room 3410, Greenbelt, MD 20771 USA. EM ziemke@jwocky.gsfc.nasa.gov NR 41 TC 11 Z9 11 U1 0 U2 3 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 JUL 10 PY 2003 VL 108 IS D13 AR 4390 DI 10.1029/2002JD002919 PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 704KP UT WOS:000184339100002 ER PT J AU Elliot, JL Ates, A Babcock, BA Bosh, AS Buie, MW Clancy, KB Dunham, EW Eikenberry, SS Hall, DT Kern, SD Leggett, SK Levine, SE Moon, DS Olkin, CB Osip, DJ Pasachoff, JM Penprase, BE Person, MJ Qu, S Rayner, JT Roberts, LC Salyk, CV Souza, SP Stone, RC Taylor, BW Tholen, DJ Thomas-Osip, JE Ticehurst, DR Wasserman, LH AF Elliot, JL Ates, A Babcock, BA Bosh, AS Buie, MW Clancy, KB Dunham, EW Eikenberry, SS Hall, DT Kern, SD Leggett, SK Levine, SE Moon, DS Olkin, CB Osip, DJ Pasachoff, JM Penprase, BE Person, MJ Qu, S Rayner, JT Roberts, LC Salyk, CV Souza, SP Stone, RC Taylor, BW Tholen, DJ Thomas-Osip, JE Ticehurst, DR Wasserman, LH TI The recent expansion of Pluto's atmosphere SO NATURE LA English DT Article ID STELLAR OCCULTATION; PLANETARY-ATMOSPHERES; ABSORPTION; PRESSURE; TRITON; MODELS AB Stellar occultations - the passing of a relatively nearby body in front of a background star - can be used to probe the atmosphere of the closer body with a spatial resolution of a few kilometres (ref. 1). Such observations can yield the scale height, temperature profile, and other information about the structure of the occulting atmosphere. Occultation data acquired for Pluto's atmosphere in 1988 revealed a nearly isothermal atmosphere(2) above a radius of similar to1,215 km. Below this level, the data could be interpreted as indicating either an extinction layer or the onset of a large thermal gradient, calling into question the fundamental structure of this atmosphere. Another question is to what extent Pluto's atmosphere might be collapsing as it recedes from the Sun ( passing perihelion in 1989 in its 248-year orbital period), owing to the extreme sensitivity of the equilibrium surface pressure to the surface temperature. Here we report observations at a variety of visible and infrared wavelengths of an occultation of a star by Pluto in August 2002. These data reveal evidence for extinction in Pluto's atmosphere and show that it has indeed changed, having expanded rather than collapsed, since 1988. C1 MIT, Dept Earth Atmospher & Planetary Sci, Cambridge, MA 02139 USA. MIT, Dept Phys, Cambridge, MA 02139 USA. MIT, Dept Aeronaut & Astronaut, Cambridge, MA 02139 USA. Lowell Observ, Flagstaff, AZ 86001 USA. Pomona Coll, Dept Phys & Astron, Claremont, CA 91711 USA. Williams Coll, Dept Phys, Williamstown, MA 01267 USA. Williams Coll, Hopkins Observ, Williamstown, MA 01267 USA. Boston Univ, Inst Astrophys Res, Boston, MA 02215 USA. Cornell Univ, Dept Astron, Ithaca, NY 14853 USA. Boeing Co, Kihei, HI 96753 USA. USN Observ, Flagstaff Stn, Flagstaff, AZ 86002 USA. NASA Infrared Telescope Facil, Honolulu, HI 96822 USA. Inst Astron, Honolulu, HI 96822 USA. RP Elliot, JL (reprint author), Carnegie Observ, Las Campanas Observ, Casilla 601, La Serena, Chile. OI Leggett, Sandy/0000-0002-3681-2989 NR 30 TC 71 Z9 71 U1 0 U2 5 PU NATURE PUBLISHING GROUP PI LONDON PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD JUL 10 PY 2003 VL 424 IS 6945 BP 165 EP 168 DI 10.1038/nature01762 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 699AA UT WOS:000184032700034 PM 12853949 ER PT J AU Stohl, A Huntrieser, H Richter, A Beirle, S Cooper, OR Eckhardt, S Forster, C James, P Spichtinger, N Wenig, M Wagner, T Burrows, JP Platt, U AF Stohl, A Huntrieser, H Richter, A Beirle, S Cooper, OR Eckhardt, S Forster, C James, P Spichtinger, N Wenig, M Wagner, T Burrows, JP Platt, U TI Rapid intercontinental air pollution transport associated with a meteorological bomb SO ATMOSPHERIC CHEMISTRY AND PHYSICS LA English DT Article ID GOME MEASUREMENTS; TROPOSPHERIC NO2; NITROGEN-OXIDES; NORTH-ATLANTIC; UNITED-STATES; OZONE; MODEL; DISTRIBUTIONS; CLIMATOLOGY; HEMISPHERE AB Intercontinental transport (ICT) of trace substances normally occurs on timescales ranging from a few days to several weeks. In this paper an extraordinary episode in November 2001 is presented, where pollution transport across the North Atlantic took only about one day. The transport mechanism, termed here an intercontinental pollution express highway because of the high wind speeds, was exceptional, as it involved an explosively generated cyclone, a so-called meteorological "bomb". To the authors' knowledge, this is the first study describing pollution transport in a bomb. The discovery of this event was based on tracer transport model calculations and satellite measurements of NO2, a species with a relatively short lifetime in the atmosphere, which could be transported that far only because of the high wind speeds produced by the bomb. A 15-year transport climatology shows that intercontinental express highways are about four times more frequent in winter than in summer, in agreement with bomb climatologies. The climatology furthermore suggests that intercontinental express highways may be important for the budget of short-lived substances in the remote troposphere. For instance, for a substance with a lifetime of 1 day, express highways may be responsible for about two thirds of the total ICT. We roughly estimate that express highways connecting North America with Europe enhance the average NOx mixing ratios over Europe, due to North American emissions, by about 2-3 pptv in winter. C1 Tech Univ Munich, Dept Ecol, D-8000 Munich, Germany. DLR, Inst Atmospher Phys, Oberpfaffenhofen, Germany. Univ Bremen, Inst Environm Phys, D-2800 Bremen 33, Germany. Univ Colorado, NOAA, Aeron Lab, CIRES, Boulder, CO 80309 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Stohl, A (reprint author), Tech Univ Munich, Dept Ecol, D-8000 Munich, Germany. RI Stohl, Andreas/A-7535-2008; Richter, Andreas/C-4971-2008; Wenig, Mark/K-7279-2012; Cooper, Owen/H-4875-2013; Eckhardt, Sabine/I-4001-2012; OI Stohl, Andreas/0000-0002-2524-5755; Richter, Andreas/0000-0003-3339-212X; Eckhardt, Sabine/0000-0001-6958-5375; Burrows, John Philip/0000-0002-6821-5580 NR 62 TC 41 Z9 42 U1 2 U2 9 PU EUROPEAN GEOPHYSICAL SOC PI KATLENBURG-LINDAU PA MAX-PLANCK-STR 13, 37191 KATLENBURG-LINDAU, GERMANY SN 1680-7324 J9 ATMOS CHEM PHYS JI Atmos. Chem. Phys. PD JUL 9 PY 2003 VL 3 BP 969 EP 985 PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 700DX UT WOS:000184098300001 ER PT J AU Fortin, TJ Drdla, K Iraci, LT Tolbert, MA AF Fortin, TJ Drdla, K Iraci, LT Tolbert, MA TI Ice condensation on sulfuric acid tetrahydrate: Implications for polar stratospheric ice clouds SO ATMOSPHERIC CHEMISTRY AND PHYSICS LA English DT Article ID PHASE-TRANSITIONS; HNO3/H2SO4/H2O SOLUTIONS; HETEROGENEOUS CHEMISTRY; ANTARCTIC STRATOSPHERE; PHYSICAL-CHEMISTRY; LIDAR OBSERVATIONS; AEROSOL DROPLETS; LOW-TEMPERATURES; CIRRUS CLOUDS; OZONE HOLE AB The mechanism of ice nucleation to form Type 2 PSCs is important for controlling the ice particle size and hence the possible dehydration in the polar winter stratosphere. This paper probes heterogeneous ice nucleation on sulfuric acid tetrahydrate (SAT). Laboratory experiments were performed using a thin-film, high-vacuum apparatus in which the condensed phase is monitored via Fourier transform infrared spectroscopy and water pressure is monitored with the combination of an MKS baratron and an ionization gauge. Results show that SAT is an efficient ice nucleus with a critical ice saturation ratio of S-ice* = 1.3 to 1.02 over the temperature range 169.8-194.5 K. This corresponds to a necessary supercooling of 0.1-1.3 K below the ice frost point. The laboratory data is used as input for a microphysical/photochemical model to probe the effect that this heterogeneous nucleation mechanism could have on Type 2 PSC formation and stratospheric dehydration. In the model simulations, even a very small number of SAT particles (e.g., 10(-3) cm(-3)) result in ice nucleation on SAT as the dominant mechanism for Type 2 PSC formation. As a result, Type 2 PSC formation is more widespread, leading to larger-scale dehydration. The characteristics of the clouds are controlled by the assumed number of SAT particles present, demonstrating that a proper treatment of SAT is critical for correctly modeling Type 2 PSC formation and stratospheric dehydration. C1 Univ Colorado, CIRES, Ctr Sci & Technol Policy Res, Boulder, CO 80309 USA. Univ Colorado, Dept Chem & Biochem, Boulder, CO 80309 USA. NASA, Ames Res Ctr, Div Earth Sci, Moffett Field, CA 94035 USA. RP Fortin, TJ (reprint author), Univ Colorado, CIRES, Ctr Sci & Technol Policy Res, 1333 Grandview Ave, Boulder, CO 80309 USA. NR 63 TC 17 Z9 17 U1 0 U2 12 PU EUROPEAN GEOPHYSICAL SOC PI KATLENBURG-LINDAU PA MAX-PLANCK-STR 13, 37191 KATLENBURG-LINDAU, GERMANY SN 1680-7324 J9 ATMOS CHEM PHYS JI Atmos. Chem. Phys. PD JUL 9 PY 2003 VL 3 BP 987 EP 997 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 700DX UT WOS:000184098300002 ER PT J AU Lepping, RP Wu, CC McClernan, K AF Lepping, RP Wu, CC McClernan, K TI Two-dimensional curvature of large angle interplanetary MHD discontinuity surfaces: IMP-8 and WIND observations SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article DE solar wind; discontinuities; interplanetary magnetic fields; variance analysis AB This study examines the degree of two-dimensional curvature of solar wind directional discontinuity ( DD) surfaces at 1 AU using magnetic field, density, and velocity data from the WIND and IMP-8 spacecraft for a large number (N=134) of carefully selected events having large "discontinuity angles'' of 90 degrees or greater. The discontinuity angle (omega) is measured in the DD's current sheet, the normal (n) to which is estimated by field variance analysis. The fundamental analysis depends on estimates of these DD surface normals at the two spacecraft and the DD's center-times and positions. On average, the transit time from one DD sighting to the other was 36 minutes, and the associated distance along the normal direction was 137 R-E. The transition-interval lengths across the DDs are translated into thicknesses and examined for the amount of change between the two spacecraft observing points. The average thickness is relatively large, 14 R-E.; the most probable thickness is approximate to 6 R-E. All relevant quantities are examined statistically to establish their distributions, average, and degree of change. A weighted average of the radius of curvature is estimated to be 380 R-E, but its most probable value is 290 R-E. The average w is 140 degrees with a relatively large spread (sigma=28 degrees). The average direction of propagation is: longitude (phi(n))=194 degrees and latitude (theta(n))=7 degrees (but =27 degrees), where phi(n)=0 degrees is sunward and theta(n)=0 degrees is the ecliptic plane. Various parameters are studied with respect to DD type, i.e., rotational or tangential discontinuity (RD or TD), defined in terms of the "ratio'' (in percent) of speed of propagation to net speed of the DD surface, where the net speed is the sum of the convection velocity (along n) plus the propagation speed. The RD %-ratio is moderately small, but the TD ratio is very small or zero. The results by this definition of type are favorably compared to those from the more conventional method, which depends on the absolute strength of the normal component of the magnetic field. There is little difference in any average parameter value according to type. However, the average appears to depend slightly on type with the for the RDs being smaller. The discontinuity type was shown to change commonly in either direction (TD to RD or RD to TD) between the two observing positions, i.e., approximate to 40% of the time. It is not clear if these type-changes are spatial or temporal. Shortcomings of the analysis are (1) the need to impose an upper limit on the angular difference of the DD normals between the two observing positions (which eliminated most surfaces of very small radii of curvature), and (2) the inability to distinguish real curvature from shorter-scale surface variations, from only two spacecraft data sets. The results of the study should help to caution us as to the simplistic use of the planar DD surface assumption in projecting, to the distance of Earth's magnetosphere, a distantly observed DD surface (e.g., one near L1), especially for studies that depend on accurately predicting the timing and characteristics of magnetospheric events. C1 NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. Univ Arizona, Tucson, AZ USA. RP NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. EM Ron.Lepping@gsfc.nasa.gov; chin-chun.wu.1@gsfc.nasa.gov; star1kat@hotmail.com NR 30 TC 15 Z9 15 U1 0 U2 0 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 JUL 9 PY 2003 VL 108 IS A7 AR 1279 DI 10.1029/2002JA009640 PG 20 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA V42AJ UT WOS:000202840100001 ER PT J AU Bauman, JJ Russell, PB Geller, MA Hamill, P AF Bauman, JJ Russell, PB Geller, MA Hamill, P TI A stratospheric aerosol climatology from SAGE II and CLAES measurements: 1. Methodology SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE stratospheric aerosols; volcanic aerosol and climate response; aerosol-climate interaction; effective radius; SAGE II; CLAES ID PINATUBO VOLCANIC AEROSOL; OPTICAL-DEPTH SPECTRA; SIZE DISTRIBUTION; EL-CHICHON; SULFURIC-ACID; HETEROGENEOUS CHEMISTRY; OZONE DESTRUCTION; VERTICAL PROFILES; REFRACTIVE-INDEX; SULFATE AEROSOLS AB [1] This paper presents the methods used to produce a global climatology of the stratospheric aerosol using data from two satellite instruments: the Stratospheric Aerosol and Gas Experiment (SAGE II) and the Cryogenic Limb Array Etalon Spectrometer (CLAES). The climatology, which spans from December 1984 to August 1999, includes values and uncertainties of measured extinction and optical depth and of retrieved particle effective radius R-eff, distribution width sigma(g), surface area S, and volume V. As a basis for aerosol retrievals, a multiwavelength look-up table ( LUT) algorithm was developed that matches the satellite-measured extinction ratios to precomputed ratios that are based on a range of unimodal lognormal size distributions. For cases in which the LUT does not find an acceptable match between measured and precomputed extinction spectra, a different technique called the parameter search technique is utilized. The combination of these two techniques and data from both satellites allows us to retrieve values of R-eff, sigma(g), S, and V over a wider range of conditions and from a wider range of wavelengths than used by other methods. This greater wavelength range helps constrain retrieved results, especially in postvolcanic conditions when particle sizes are greatly increased and SAGE II extinction spectra become essentially independent of wavelength. Our method includes an altitude- and time-dependent procedure that uses bimodal size distributions from in situ measurements to estimate bias and uncertainty introduced by assuming a unimodal functional form. Correcting for this bias reduces uncertainty in retrievals of R-eff, S, and V by about 7%, 5%, and 1% ( averaged over all altitude bands), leaving remaining uncertainties from the unimodal assumption of about +/-18%, +/-20%, and +/-21%, respectively. Additional uncertainties, resulting from measurement error and spatiotemporal variability, are evaluated by propagating input uncertainties through the retrieval algorithm. In an accompanying paper we report on a climatology of R-eff, S, and V and consider uncertainties in our retrieved values of these parameters. In this paper we examine the sensitivity of our retrievals to refractive index and measurement wavelength. We find, for example, that changing refractive index from a value for the stratospheric temperature of 215 K to that for 300 K can increase retrieved R-eff by similar to7.5%, owing largely to effects at the CLAES 12.82 mum wavelength. When only SAGE II wavelengths are used, corresponding changes in R-eff are much smaller. C1 NASA, Ames Res Ctr, Adv Projects Branch, Moffett Field, CA 94035 USA. SUNY Stony Brook, Inst Terr & Planetary Atmospheres, Stony Brook, NY 11794 USA. San Jose State Univ, Dept Phys, San Jose, CA 95192 USA. RP Bauman, JJ (reprint author), NASA, Ames Res Ctr, Adv Projects Branch, Mail Stop 244-14, Moffett Field, CA 94035 USA. EM jbauman@mail.arc.nasa.gov; prussell@mail.arc.nasa.gov; marvin.geller@sunysb.edu; hamill@stratus.arc.nasa.gov NR 53 TC 18 Z9 18 U1 0 U2 3 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 JUL 8 PY 2003 VL 108 IS D13 AR 4382 DI 10.1029/2002JD002992 PG 19 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 704KL UT WOS:000184338800005 ER PT J AU Bauman, JJ Russell, PB Geller, MA Hamill, P AF Bauman, JJ Russell, PB Geller, MA Hamill, P TI A stratospheric aerosol climatology from SAGE II and CLAES measurements: 2. Results and comparisons, 1984-1999 SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE stratospheric aerosols; volcanic aerosol and climate response; aerosol-climate interaction; effective radius; SAGE II; CLAES ID EXPLOSIVE VOLCANIC-ERUPTIONS; SIZE DISTRIBUTION; MESOSPHERIC SOUNDER; PINATUBO AEROSOL; MOUNT-PINATUBO; SURFACE-AREA; EL-CHICHON; DISTRIBUTIONS; TEMPERATURE; SATELLITE AB [1] This paper presents a climatology of the stratospheric aerosol produced with our look-up table (LUT) technique using data from the Stratospheric Aerosol and Gas Experiment (SAGE II) and the Cryogenic Limb Array Etalon Spectrometer (CLAES) instruments. The LUT climatology spans the period from December 1984 to August 1999. It includes values and uncertainties of measured extinction and optical depth at four SAGE II wavelengths (0.385-1.02 mum) and supplements these with results from the CLAES 12.82 mum wavelength during the key period January 1992 through May 1993, when the large particle sizes from the Pinatubo volcanic injection made many SAGE II extinction and optical depth spectra wavelength independent. Also included are retrieved values of effective radius R-eff, distribution width sigma(g), surface area S, and volume V. Aerosol retrievals show notable increases in all these parameters after major volcanic eruptions, with increases in R-eff lagging increases in the others. Postvolcanic increases in sigma(g), indicative of broader size distributions, are consistent with sudden increases in numbers of both small and large particles that exceed increases in intermediate-size particles. After Pinatubo, retrieved R-eff and sigma(g) took nearly 5 years to return to pre-eruption values, while slightly shorter recovery times were obtained for S and V. During low- aerosol-loading periods, size distributions narrow in going from the tropical core to higher latitudes at altitudes between 20 and 22 km. Seasonal variations in S and V are observed at high latitudes for several altitude bands, but are less obvious in R-eff. With some exceptions, LUT retrievals agree well with most previous climatologies. For example, agreement is good between LUT retrieved surface area and results from balloon-borne measurements, where available. However, there are a few noteworthy discrepancies. For example, values of surface area from principal component analysis of SAGE II data are less than LUT retrievals during near-background periods (e.g., 1989 to mid-1991, and after 1996) and greater than LUT retrievals in the peak of the Pinatubo plume. The smaller LUT-derived surface areas during the Pinatubo peak result from the constraint provided by the CLAES 12.82 mum extinction measurements. C1 NASA, Ames Res Ctr, Adv Projects Branch, Moffett Field, CA 94035 USA. SUNY Stony Brook, Inst Terr & Planetary Atmospheres, Stony Brook, NY 11794 USA. San Jose State Univ, Dept Phys, San Jose, CA 95192 USA. RP Bauman, JJ (reprint author), NASA, Ames Res Ctr, Adv Projects Branch, Mail Stop 244-14, Moffett Field, CA 94035 USA. EM jbauman@mail.arc.nasa.gov; prussell@mail.arc.nasa.gov; marvin.geller@sunysb.edu; hamill@stratus.arc.nasa.gov NR 42 TC 47 Z9 50 U1 0 U2 9 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 JUL 8 PY 2003 VL 108 IS D13 AR 4383 DI 10.1029/2002JD002993 PG 30 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 704KL UT WOS:000184338800006 ER PT J AU Riley, P Linker, JA Mikic, Z Odstrcil, D Zurbuchen, TH Lario, D Lepping, RP AF Riley, P Linker, JA Mikic, Z Odstrcil, D Zurbuchen, TH Lario, D Lepping, RP TI Using an MHD simulation to interpret the global context of a coronal mass ejection observed by two spacecraft SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article DE coronal mass ejections; CMEs; MHD simulations; in situ observations ID STRUCTURED SOLAR-WIND; INTERPLANETARY MAGNETIC CLOUDS; 3-DIMENSIONAL PROPAGATION; FLUX ROPE; HELMET STREAMER; FIELD; ULYSSES; RECONNECTION; MODELS; SHOCK AB [1] In late February 1999 the ACE spacecraft observed a coronal mass ejection (CME) at 1 AU, in the ecliptic plane. Thirteen days later, Ulysses observed a CME at 5 AU and 22 degreesS. We present a detailed analysis of the plasma, magnetic field, and composition signatures of these two events. On the basis of this comparison alone, it is not clear that the two spacecraft observed the same solar event. However, using a generic MHD simulation of a fast CME initiated at the Sun by magnetic flux cancellation and propagated out into the solar wind, together with additional evidence, we argue that indeed the same CME was observed by both spacecraft. Although force-free models appear to fit the observed events well, our simulation results suggest that the ejecta underwent significant distortion during its passage through the solar wind, indicating that care should be taken when interpreting the results of force-free models. Comparison of composition measurements at the two spacecraft suggests that significant spatial inhomogeneities can exist within a single CME. C1 Sci Applicat Int Corp, San Diego, CA 92121 USA. NOAA, Space Environm Ctr, Boulder, CO 80305 USA. Univ Michigan, Dept Atmospher Ocean & Space Sci, Ann Arbor, MI 48109 USA. Johns Hopkins Univ, Appl Phys Lab, Laurel, MD 20723 USA. NASA, Extraterr Phys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Sci Applicat Int Corp, San Diego, CA 92121 USA. EM pete.riley@saic.com; linker@iris023.saic.com; mikic@iris023.saic.com; Dusan.Odstrcil@noaa.gov; thomasz@umich.edu; david.lario@jhuapl.edu; Ron.Lepping@gsfc.nasa.gov RI Lario, David/D-9318-2016 OI Lario, David/0000-0002-3176-8704 NR 41 TC 65 Z9 66 U1 0 U2 2 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 JUL 8 PY 2003 VL 108 IS A7 AR 1272 DI 10.1029/2002JA009760 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 705ZB UT WOS:000184426200004 ER PT J AU Ross, JA AF Ross, JA TI Apollo debris needs decision SO AVIATION WEEK & SPACE TECHNOLOGY LA English DT Letter C1 NASA, Elect Syst Test Lab, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Ross, JA (reprint author), NASA, Elect Syst Test Lab, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU MCGRAW HILL INC PI NEW YORK PA 1221 AVENUE OF THE AMERICAS, NEW YORK, NY 10020 USA SN 0005-2175 J9 AVIAT WEEK SPACE TEC JI Aviat. Week Space Technol. PD JUL 7 PY 2003 VL 159 IS 1 BP 6 EP 6 PG 1 WC Engineering, Aerospace SC Engineering GA 699FH UT WOS:000184045700005 ER PT J AU Merka, J Szabo, A Safrankova, J Nemecek, Z AF Merka, J Szabo, A Safrankova, J Nemecek, Z TI Earth's bow shock and magnetopause in the case of a field-aligned upstream flow: Observation and model comparison SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article DE bow shock; magnetopause; magnetosheath thickness; field-aligned flow; IMP 8; Interball-1 ID SOLAR-WIND CONDITIONS; STANDOFF DISTANCE; UNUSUAL LOCATIONS; MACH NUMBERS; MHD THEORY; SHAPE; MAGNETOSPHERE; ORIENTATION; POSITION; PLASMA AB [1] On 5 May 1996 the Interball-1 and IMP 8 spacecraft crossed the bow shock boundary. The upstream conditions were special in two factors: ( 1) the interplanetary magnetic field was anti-parallel to the solar wind flow within 15degrees and (2) the conditions were stable for a prolonged period (similar to9 hours). At the nose of the magnetosphere, the Interball-1 data revealed that the magnetopause was farther outward by similar to2 R-E than model predictions and the subsolar magnetosheath was unusually thin, at most 10% of the magnetopause standoff distance. Both results stand in contrast to predictions of existing magnetopause/bow shock models. Assuming a hyperboloidal ( paraboloidal) shock wave, the calculated shock's standoff distance was 13.7 (13.6) R-E, and the focus was located on the x axis at 4.5 (4.2) R-E. On the basis of the IMP 8 observation, the bow shock flares significantly less than MHD simulations predict for a field-aligned bow shock at the magnetospheric flanks. This study discusses differences between the observations and existing MHD bow shock simulations for field-aligned upstream flow. Furthermore, it is suggested that the flow-aligned IMF orientation causes a significant change of the magnetopause shape into a bullet-like obstacle. C1 NASA, Extraterr Phys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Charles Univ Prague, Fac Math & Phys, CR-18000 Prague 8, Czech Republic. RP NASA, Extraterr Phys Lab, Goddard Space Flight Ctr, Code 696, Greenbelt, MD 20771 USA. EM jan.merka@gsfc.nasa.gov; adam.szabo@gsfc.nasa.gov; jana.safrankova@mff.cuni.cz; zdenek.nemecek@mff.cuni.cz NR 36 TC 44 Z9 44 U1 0 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 JUL 3 PY 2003 VL 108 IS A7 AR 1269 DI 10.1029/2002JA009697 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 698WP UT WOS:000184022600002 ER PT J AU Tsurutani, BT Gonzalez, WD Lakhina, GS Alex, S AF Tsurutani, BT Gonzalez, WD Lakhina, GS Alex, S TI The extreme magnetic storm of 1-2 September 1859 SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article DE solar flares; interplanetary CMEs; extreme magnetic storms; auroras; space weather ID SOLAR-WIND; RING CURRENT; VISCOUS INTERACTION; GEOMAGNETIC STORMS; ELECTRIC-FIELDS; AUGUST 1972; MAGNETOSPHERE; ENERGY; EFFICIENCY; MOTION AB [1] The 1 - 2 September 1859 magnetic storm was the most intense in recorded history on the basis of previously reported ground observations and on newly reduced ground-based magnetic field data. Using empirical results on the interplanetary magnetic field strengths of magnetic clouds versus velocities, we show that the 1 September 1859 Carrington solar flare most likely had an associated intense magnetic cloud ejection which led to a storm on Earth of D-ST similar to - 1760 nT. This is consistent with the Colaba, India local noon magnetic response of DeltaH = 1600 +/- 10 nT. It is found that both the 1 - 2 September 1859 solar flare energy and the associated coronal mass ejection speed were extremely high but not unique. Other events with more intense properties have been detected; thus a storm of this or even greater intensity may occur again. Because the data for the high-energy tails of solar flares and magnetic storms are extremely sparse, the tail distributions and therefore the probabilities of occurrence cannot be assigned with any reasonable accuracy. A further complication is a lack of knowledge of the saturation mechanisms of flares and magnetic storms. These topics are discussed in some detail. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Inst Nacl Pesquisas Espaciais, Sao Paulo, Brazil. Indian Inst Geomagnetism, Bombay 400005, Maharashtra, India. RP Tsurutani, BT (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Lakhina, Gurbax /C-9295-2012 NR 45 TC 156 Z9 160 U1 6 U2 22 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 JUL 3 PY 2003 VL 108 IS A7 AR 1268 DI 10.1029/2002JA009504 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 698WP UT WOS:000184022600001 ER PT J AU Chakrabarty, D Morgan, EH Muno, MP Galloway, DK Wijnands, R van der Klis, M Markwardt, CB AF Chakrabarty, D Morgan, EH Muno, MP Galloway, DK Wijnands, R van der Klis, M Markwardt, CB TI Nuclear-powered millisecond pulsars and the maximum spin frequency of neutron stars SO NATURE LA English DT Article ID X-RAY-BURSTS; GRAVITATIONAL-RADIATION; BINARY; DISCOVERY; OSCILLATIONS; SYSTEM AB Millisecond pulsars are neutron stars that are thought to have been spun-up by mass accretion from a stellar companion(1). It is not known whether there is a natural brake for this process, or if it continues until the centrifugal breakup limit is reached at submillisecond periods. Many neutron stars that are accreting mass from a companion star exhibit thermonuclear X-ray bursts that last tens of seconds, caused by unstable nuclear burning on their surfaces(2). Millisecond-period brightness oscillations during bursts from ten neutron stars (as distinct from other rapid X-ray variability that is also observed(3,4)) are thought to measure the stellar spin(2,5), but direct proof of a rotational origin has been lacking. Here we report the detection of burst oscillations at the known spin frequency of an accreting millisecond pulsar, and we show that these oscillations always have the same rotational phase. This firmly establishes burst oscillations as nuclear-powered pulsations tracing the spin of accreting neutron stars, corroborating earlier evidence(5,6). The distribution of spin frequencies of the 11 nuclear-powered pulsars cuts off well below the breakup frequency for most neutron-star models, supporting theoretical predictions that gravitational radiation losses can limit accretion torques in spinning up millisecond pulsars(7-9). C1 MIT, Dept Phys, Cambridge, MA 02139 USA. MIT, Ctr Space Res, Cambridge, MA 02139 USA. Univ Calif Santa Barbara, Kavli Inst Theoret Phys, Santa Barbara, CA 93106 USA. Univ St Andrews, Sch Phys & Astron, St Andrews KY16 9SS, Fife, Scotland. Univ Amsterdam, Astron Inst Anton Pannekoek, NL-1098 SJ Amsterdam, Netherlands. Univ Amsterdam, Ctr High Energy Astrophys, NL-1098 SJ Amsterdam, Netherlands. Univ Maryland, Dept Astron, College Pk, MD 20742 USA. NASA, High Energy Astrophys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP MIT, Dept Phys, Cambridge, MA 02139 USA. EM deepto@space.mit.edu OI Galloway, Duncan/0000-0002-6558-5121 NR 30 TC 262 Z9 263 U1 0 U2 1 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 JUL 3 PY 2003 VL 424 IS 6944 BP 42 EP 44 DI 10.1038/nature01732 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 696XL UT WOS:000183912800032 PM 12840751 ER PT J AU Wijnands, R van der Klis, M Homan, J Chakrabarty, D Markwardt, CB Morgan, EH AF Wijnands, R van der Klis, M Homan, J Chakrabarty, D Markwardt, CB Morgan, EH TI Quasi-periodic X-ray brightness fluctuations in an accreting millisecond pulsar SO NATURE LA English DT Article ID OSCILLATION PEAK SEPARATION; NEUTRON-STAR; DIFFERENCE-FREQUENCY; 4U 1636-53; BINARIES; SYSTEM; MODEL; PRECESSION; CONSTANT; FIELD AB The relativistic plasma flows onto neutron stars that are accreting material from stellar companions can be used to probe strong-field gravity as well as the physical conditions in the supranuclear-density interiors of neutron stars. Plasma inhomogeneities orbiting a few kilometres above the stars are observable as X-ray brightness fluctuations on the millisecond dynamical timescale of the flows(1-3). Two frequencies in the kilohertz range dominate these fluctuations: the twin kilohertz quasi-periodic oscillations (kHz QPOs). Competing models for the origins of these oscillations (based on orbital motions) all predict that they should be related to the stellar spin frequency(4-10), but tests have been difficult because the spins were not unambiguously known. Here we report the detection of kHz QPOs from a pulsar whose spin frequency is known. Our measurements establish a clear link between kHz QPOs and stellar spin, but one not predicted by any current model. A new approach to understanding kHz QPOs is now required. We suggest that a resonance between the spin and general relativistic orbital and epicyclic frequencies could provide the observed relation between QPOs and spin. C1 Univ St Andrews, Sch Phys & Astron, St Andrews KY16 9SS, Fife, Scotland. Univ Amsterdam, Astron Inst Anton Pannekoek, NL-1098 SJ Amsterdam, Netherlands. Natl Inst Nucl & High Energy Phys, Ctr High Energy Astrophys, NL-1098 SJ Amsterdam, Netherlands. INAF, Osservatorio Astron Brera, I-23807 Merate LC, Italy. MIT, Ctr Space Res, Cambridge, MA 02139 USA. NASA, High Energy Astrophys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Wijnands, R (reprint author), Univ St Andrews, Sch Phys & Astron, St Andrews KY16 9SS, Fife, Scotland. NR 30 TC 131 Z9 133 U1 0 U2 1 PU NATURE PUBLISHING GROUP PI LONDON PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD JUL 3 PY 2003 VL 424 IS 6944 BP 44 EP 47 DI 10.1038/nature01754 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 696XL UT WOS:000183912800033 PM 12840752 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, JF 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, JW Moiseev, AA Nishimura, J Nozaki, M Orito, S Ormes, JF 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 TI Measurements of proton, helium and muon spectra at small atmospheric depths with the BESS spectrometer SO PHYSICS LETTERS B LA English DT Article DE atmospheric muon; cosmic-ray proton; cosmic-ray helium; atmospheric neutrino; superconducting spectrometer ID ONBOARD BESS AB The cosmic-ray proton, helium, and muon spectra at small atmospheric depths of 4.5-28 g/cm(2) were precisely measured during the slow descending period of the BESS-2001 balloon flight. The variation of atmospheric secondary particle fluxes as a function of atmospheric depth provides fundamental information to study hadronic interactions of the primary cosmic rays with the atmosphere. (C) 2003 Published by Elsevier Science B.V. C1 Kobe Univ, Kobe, Hyogo 6578501, Japan. 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), Kobe Univ, Kobe, Hyogo 6578501, Japan. OI Seo, Eun-Suk/0000-0001-8682-805X NR 21 TC 33 Z9 33 U1 0 U2 1 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 JUL 3 PY 2003 VL 564 IS 1-2 BP 8 EP 20 DI 10.1016/S0370-2693(03)00676-2 PG 13 WC Astronomy & Astrophysics; Physics, Nuclear; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 693AK UT WOS:000183692300002 ER PT J AU Fishman, J Wozniak, AE Creilson, JK AF Fishman, J Wozniak, AE Creilson, JK TI Global distribution of tropospheric ozone from satellite measurements using the empirically corrected tropospheric ozone residual technique: Identification of the regional aspects of air pollution SO ATMOSPHERIC CHEMISTRY AND PHYSICS LA English DT Article ID MAPPING SPECTROMETER; TOMS MEASUREMENTS; COLUMN OZONE; CLIMATOLOGY; ULTRAVIOLET; AEROSOL; EPISODE; TRENDS; OCEAN AB Using coincident observations of total ozone from the Total Ozone Mapping Spectrometer (TOMS) and stratospheric ozone profiles from the Solar Backscattered Ultraviolet (SBUV) instruments, detailed maps of tropospheric ozone have been derived on a daily basis over a time period spanning more than two decades. The resultant climatological seasonal depictions of the tropospheric ozone residual (TOR) show much more detail than an earlier analysis that had used coincident TOMS and Stratospheric Aerosol and Gas Experiment (SAGE) ozone profiles, although there are many similarities between the TOMS/SAGE TOR and the TOMS/SBUV TOR climatologies. In particular, both TOR seasonal depictions show large enhancements in the southern tropics and subtropics in austral spring and at northern temperate latitudes during the summer. The much greater detail in this new data set clearly defines the regional aspect of tropospheric ozone pollution in northeastern India, eastern United States, eastern China, and west and southern Africa. Being able to define monthly climatologies for each year of the data record provides enough temporal resolution to illustrate significant interannual variability in some of these regions. C1 NASA, Langley Res Ctr, Hampton, VA 23665 USA. Sci Applicat Int Corp, Hampton, VA USA. RP Fishman, J (reprint author), NASA, Langley Res Ctr, Hampton, VA 23665 USA. NR 32 TC 112 Z9 120 U1 0 U2 13 PU EUROPEAN GEOPHYSICAL SOC PI KATLENBURG-LINDAU PA MAX-PLANCK-STR 13, 37191 KATLENBURG-LINDAU, GERMANY SN 1680-7324 J9 ATMOS CHEM PHYS JI Atmos. Chem. Phys. PD JUL 2 PY 2003 VL 3 BP 893 EP 907 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 700DR UT WOS:000184097800001 ER PT J AU Vinnik, L Montagner, JP Girardin, N Dricker, I Saul, J AF Vinnik, L Montagner, JP Girardin, N Dricker, I Saul, J TI Comment on "Shear-wave splitting to test mantle deformation models around Hawaii" by Kristoffer T. Walker, Gotz H. R. Bokelmann, and Simon L. Klemperer SO GEOPHYSICAL RESEARCH LETTERS LA English DT Editorial Material ID ANISOTROPY; PACIFIC; PLATE C1 Geoforschungszentrum Potsdam, D-14473 Potsdam, Germany. Russian Acad Sci, Inst Phys Earth, Moscow 123810, Russia. CALTECH, Jet Prop Lab, Pasadena, CA USA. Instrumental Software Technol Inc, Saratoga Springs, NY USA. Inst Phys Globe, Dept Seismol, UMR 7580, F-75252 Paris, France. RP Vinnik, L (reprint author), Geoforschungszentrum Potsdam, Telegrafenberg, D-14473 Potsdam, Germany. RI Montagner, Jean-Paul/A-8733-2011 OI Montagner, Jean-Paul/0000-0001-9958-3012 NR 10 TC 5 Z9 5 U1 0 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 JUL 2 PY 2003 VL 30 IS 13 AR 1675 DI 10.1029/2002GL015751 PG 2 WC Geosciences, Multidisciplinary SC Geology GA 698LZ UT WOS:000184002200001 ER PT J AU Livesey, NJ Read, WG Froidevaux, L Waters, JW Santee, ML Pumphrey, HC Wu, DL Shippony, Z Jarnot, RF AF Livesey, NJ Read, WG Froidevaux, L Waters, JW Santee, ML Pumphrey, HC Wu, DL Shippony, Z Jarnot, RF TI The UARS microwave limb sounder version 5 data set: Theory, characterization, and validation SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE Microwave Limb Sounder (MLS); Upper Atmosphere Research Satellite (UARS); upper tropospheric humidity; stratospheric ozone; stratospheric composition; stratospheric chemistry ID ATMOSPHERE RESEARCH SATELLITE; GAS EXPERIMENT II; CHLORINE MONOXIDE; STRATOSPHERIC AEROSOL; HNO3 OBSERVATIONS; OZONE TRENDS; WATER-VAPOR; SAGE-II; INSTRUMENT; VORTEX AB This paper describes the latest and (for most products) definitive data set from the Microwave Limb Sounder (MLS) on the Upper Atmosphere Research Satellite (UARS). MLS data have formed the basis of numerous studies, and the version 5 data, produced using more advanced algorithms than earlier versions, represent a significant improvement in quality and scientific applicability for most of the MLS data products. The version 5 data include midstratospheric to lower mesospheric temperature and geopotential height (the latter is a new product from MLS), water vapor from the upper troposphere to the mesosphere, stratospheric and mesospheric ozone, and stratospheric nitric acid, chlorine monoxide, and methyl cyanide (also a new product). The vertical retrieval grid over the stratosphere and lower mesosphere has been doubled, to six surfaces per decade change in pressure (similar to2.5 km), compared to three surfaces per decade in previous versions. The accuracy and precision of lower stratospheric ozone, chlorine monoxide, and nitric acid have been improved. For each product, a description of relevant changes to the algorithms is given, along with an update on its validation, a description of the accuracy, precision, and vertical resolution of the data, and information on what quality control methods to apply when using the data. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Edinburgh, Inst Meteorol, Edinburgh EH9 3JZ, Midlothian, Scotland. RP Livesey, NJ (reprint author), CALTECH, Jet Prop Lab, MS 183-701,4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM livesey@mls.jpl.nasa.gov; bill@mls.jpl.nasa.gov; lucien@mls.jpl.nasa.gov; joe@mls.jpl.nasa.gov; mls@mls.jpl.nasa.gov; hcp@met.ed.ac.uk; dwu@mls.jpl.nasa.gov; jarnot@mls.jpl.nasa.gov RI Wu, Dong/D-5375-2012 NR 35 TC 60 Z9 60 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 JUL 2 PY 2003 VL 108 IS D13 AR 4378 DI 10.1029/2002JD002273 PG 21 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 698MJ UT WOS:000184003100001 ER PT J AU Livingston, JM Russell, PB Reid, JS Redemann, J Schmid, B Allen, DA Torres, O Levy, RC Remer, LA Holben, BN Smirnov, A Dubovik, O Welton, EJ Campbell, JR Wang, J Christopher, SA AF Livingston, JM Russell, PB Reid, JS Redemann, J Schmid, B Allen, DA Torres, O Levy, RC Remer, LA Holben, BN Smirnov, A Dubovik, O Welton, EJ Campbell, JR Wang, J Christopher, SA TI Airborne Sun photometer measurements of aerosol optical depth and columnar water vapor during the Puerto Rico Dust Experiment and comparison with land, aircraft, and satellite measurements SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE PRIDE; airborne Sun photometer; aerosol optical depth; columnar water vapor; AATS-6 ID BACKSCATTERED ULTRAVIOLET-RADIATION; OZONE MAPPING SPECTROMETER; BIOMASS BURNING AEROSOLS; NORTH-ATLANTIC OCEAN; SAHARAN DUST; IN-SITU; TROPOSPHERIC AEROSOL; MINERAL AEROSOLS; UNITED-STATES; SUNPHOTOMETER MEASUREMENTS AB [1] Analyses of aerosol optical depth (AOD) and columnar water vapor (CWV) measurements obtained with the six-channel NASA Ames Airborne Tracking Sunphotometer (AATS-6) mounted on a twin-engine aircraft during the summer 2000 Puerto Rico Dust Experiment are presented. In general, aerosol extinction values calculated from AATS-6 AOD measurements acquired during aircraft profiles up to 5 km above sea level (asl) reproduce the vertical structure measured by coincident aircraft in situ measurements of total aerosol number concentration. AATS-6 extinction retrievals also agree with corresponding values derived from ground-based lidar measurements for altitudes above the trade inversion. The spectral behavior of AOD within specific layers beneath the top of the aircraft profile is consistent with attenuation of incoming solar radiation by large dust particles or by dust plus sea salt, with mean Angstrom wavelength exponents of similar to0.20. Values of CWV calculated from profile measurements by AATS-6 at 941.9 nm and from aircraft in situ measurements agree to within similar to4% (0.13 g/cm(2)). AATS-6 AOD values measured on the ground at Roosevelt Roads Naval Air Station and during low-altitude aircraft runs over the adjacent Cabras Island aerosol/radiation ground site agree to within 0.004-0.030 with coincident data obtained with an AERONET Sun/sky radiometer located on Cabras Island. For the same observation times, AERONET retrievals of CWV exceed AATS-6 values by similar to21%. AATS-6 AOD values measured during low-altitude aircraft traverses over the ocean are compared with corresponding AOD values retrieved over water from upwelling radiance measurements by the Moderate-Resolution Imaging Spectroradiometer (MODIS), Total Ozone Mapping Spectrometer (TOMS), and GOES 8 Imager satellite sensors, with mixed results. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Sci Syst & Applicat Inc, Lanham, MD 20706 USA. NASA, Goddard Environm Sci & Technol Ctr, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NASA, Terr Phys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. SRI Int, Menlo Pk, CA 94025 USA. Bay Area Environm Res Inst, Sonoma, CA 95476 USA. USN, Marine Meteorol Div, Res Lab, Monterey, CA 93943 USA. NASA, Atmospheres Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Maryland Baltimore Cty, Joint Ctr Earth Syst Technol, Baltimore, MD 21250 USA. Univ Alabama, Dept Atmospher Sci, Huntsville, AL 35899 USA. RP Livingston, JM (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. EM jlivingston@mail.arc.nasa.gov RI Dubovik, Oleg/A-8235-2009; Smirnov, Alexander/C-2121-2009; Christopher, Sundar/E-6781-2011; Welton, Ellsworth/A-8362-2012; Campbell, James/C-4884-2012; Levy, Robert/M-7764-2013; Reid, Jeffrey/B-7633-2014; Torres, Omar/G-4929-2013; Wang, Jun/A-2977-2008 OI Dubovik, Oleg/0000-0003-3482-6460; Smirnov, Alexander/0000-0002-8208-1304; Campbell, James/0000-0003-0251-4550; Levy, Robert/0000-0002-8933-5303; Reid, Jeffrey/0000-0002-5147-7955; Wang, Jun/0000-0002-7334-0490 NR 92 TC 29 Z9 28 U1 1 U2 3 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 JUL 2 PY 2003 VL 108 IS D19 AR 8588 DI 10.1029/2002JD002520 PG 23 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 698MU UT WOS:000184004000001 ER PT J AU O'Sullivan, C Dingliana, J Giang, T Kaiser, MK AF O'Sullivan, C Dingliana, J Giang, T Kaiser, MK TI Evaluating the visual fidelity of physically based animations SO ACM TRANSACTIONS ON GRAPHICS LA English DT Article; Proceedings Paper CT Annual Symposium of the ACM SIGGRAPH CY JUL 27-31, 2003 CL SAN DIEGO, CA SP ACM, SIGGRAPH DE animation; plausible simulation; collision handling; perceptual metrics; evaluation ID COLLISION DETECTION; PERCEPTION; DYNAMICS; MOTIONS AB For many systems that produce physically based animations, plausibility rather than accuracy is acceptable. We consider the problem of evaluating the visual quality of animations in which physical parameters have been distorted or degraded, either unavoidably due to real-time frame-rate requirements, or intentionally for aesthetic reasons. To date, no generic means of evaluating or predicting the fidelity, either physical or visual, of the dynamic events occurring in an animation exists. As a first step towards providing such a metric, we present a set of psychophysical experiments that established some thresholds for human sensitivity to dynamic anomalies, including angular, momentum and spatio-temporal distortions applied to simple animations depicting the elastic collision of two rigid objects. In addition to finding significant acceptance thresholds for these distortions under varying conditions, we identified some interesting biases that indicate non-symmetric responses to these distortions (e.g., expansion of the angle between post-collision trajectories was preferred to contraction and increases in velocity were preferred to decreases). Based on these results, we derived a set of probability functions that can be used to evaluate the visual fidelity of a physically based simulation. To illustrate how our results could be used, two simple case studies of simulation levels of detail and constrained dynamics are presented. C1 Univ Dublin Trinity Coll, Dublin 2, Ireland. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Univ Dublin Trinity Coll, Dublin 2, Ireland. EM Carol.OSullivan@cs.tcd.ie; John.Dingliana@cs.tcd.ie; Thanh.Giang@cs.tcd.ie; mkaiser@mail.arc.nasa.gov OI Dingliana, John/0000-0001-7636-6402; O'Sullivan, Carol/0000-0003-3772-4961 NR 39 TC 32 Z9 32 U1 0 U2 3 PU ASSOC COMPUTING MACHINERY PI NEW YORK PA 2 PENN PLAZA, STE 701, NEW YORK, NY 10121-0701 USA SN 0730-0301 EI 1557-7368 J9 ACM T GRAPHIC JI ACM Trans. Graph. PD JUL PY 2003 VL 22 IS 3 BP 527 EP 536 DI 10.1145/882262.882303 PG 10 WC Computer Science, Software Engineering SC Computer Science GA 703QD UT WOS:000184291700035 ER PT J AU Erickson, JK Bindschadler, DL Theilig, EE Vandermey, N AF Erickson, JK Bindschadler, DL Theilig, EE Vandermey, N TI Project Galileo: surviving Io, meeting Cassini SO ACTA ASTRONAUTICA LA English DT Article AB Galileo has completed the long awaited Io flybys of the Galileo Europa Mission and the Galileo Millennium Mission, and is now pumping up its apajove in each succeeding orbit in preparation for the chance to perform a dual spacecraft observation of the Jupiter System. Making up for the missed opportunity at the beginning of Galileo's primary mission, a total of three close passes by Io have given us an up close and personal look at this highly volcanic body. The results presented include new and exciting information about Io's interactions with Jupiter's magnetosphere., its interior structure, and amazing volcanoes. Galileo Millennium Mission results from a magnetic field study of Europa, and its likely impact on the question of a European ocean are provided. In addition the engineering challenges of operating the spacecraft during the past year are explored, as well as a brief examination of future challenges. The spacecraft has now experienced more than three times the radiation dose it was designed to, and this exposure is contributing to a number of spacecraft problems and concerns. The engineering data being generated by these continuing radiation-induced anomalies, and the ability of the spacecraft to survive these doses, will prove invaluable to designers of future spacecraft to Jupiter and its satellites. (C) 2003 Elsevier Science Ltd. All rights reserved. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Erickson, JK (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 11 TC 0 Z9 0 U1 0 U2 1 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 JUL PY 2003 VL 53 IS 2 BP 85 EP 122 DI 10.1016/S0094-5765(02)00276-X PG 38 WC Engineering, Aerospace SC Engineering GA 685EN UT WOS:000183248000001 ER PT J AU Gayda, J Furrer, D AF Gayda, J Furrer, D TI Dual-micro heat treat SO ADVANCED MATERIALS & PROCESSES LA English DT Article AB Rotating disks for aircraft engines and land-based turbines must withstand higher operating temperatures and demonstrate longer service life than ever before, while also minimizing costs. One design and processing approach is to develop disk components with distinctly different microstructures optimized for required mechanical properties at various regions within the disks. A new method has been developed and demonstrated on a production scale to produce dual-microstructure disks in a very controllable, reproducible, and cost-effective manner. This article describes disk requirements, discusses the dual-microstructure heat treatment, and reports results of extensive testing of the dual-microstructure turbine engine disks. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. Ladish Co Inc, Cudahy, WI 53110 USA. RP Gayda, J (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. NR 0 TC 5 Z9 7 U1 0 U2 3 PU ASM INTERNATIONAL PI MATERIALS PARK PA SUBSCRIPTIONS SPECIALIST CUSTOMER SERVICE, MATERIALS PARK, OH 44073-0002 USA SN 0882-7958 J9 ADV MATER PROCESS JI Adv. Mater. Process. PD JUL PY 2003 VL 161 IS 7 BP 36 EP 39 PG 4 WC Materials Science, Multidisciplinary SC Materials Science GA 700HH UT WOS:000184106200005 ER PT J AU Fragomeni, JM Nunes, AC AF Fragomeni, JM Nunes, AC TI A study of the effects of welding parameters on electron beam welding in the space environment SO AEROSPACE SCIENCE AND TECHNOLOGY LA English DT Article DE electron beam welding; space; molten metal; detachments; filler metal; vacuum; gravity AB This study was undertaken in order to be sure that no hazard would exist from impingement of hot molten metal particle detachments upon an astronauts' space suit during any future electron beam welding exercises or experiments. The conditions under which molten metal detachments might occur in a space welding environment were analyzed. The safety issue is important during welding with regards to potential molten metal detachments from the weld pool and cold filler wire during electron beam welding in space. This investigation was undertaken to evaluate if molten metal could detach and come in contact with astronauts and burn through the fabric of the astronauts' Extravehicular Mobility Unit during electron beam welding in space. Molten metal detachments from either the weld/cut substrate or weld wire could present harm to an astronaut if the detachment was to burn through the fabric of the astronauts' space suit. Theoretical models were developed to predict the possibility and size of the molten metal detachment hazards during the electron beam welding exercises at Low Earth Orbit. Some possible ways of obtaining molten metal drop detachments would include an impulse force, or bump, to the weld sample, cut surface, or filler wire. Theoretical models were developed for these detachment concerns from principles of impact and kinetic energies, surface tension. drop geometry, surface energies, and particle dynamics. A weld pool detachment parameter for specifying the conditions for metal weld pool detachment by impact was derived and correlated to the experimental results. The experimental results were for the most part consistent with the theoretical analysis and predictions. (C) 2003 Editions scientifiques et medicales Elsevier SAS. All rights reserved. C1 Univ Detroit, Coll Engn & Sci, Dept Mech Engn, Detroit, MI 48221 USA. NASA, George C Marshall Space Flight Ctr, Mat Proc & Mfg Dept, Huntsville, AL 35812 USA. RP Fragomeni, JM (reprint author), Univ Detroit, Coll Engn & Sci, Dept Mech Engn, Detroit, MI 48221 USA. NR 9 TC 1 Z9 1 U1 0 U2 7 PU EDITIONS SCIENTIFIQUES MEDICALES ELSEVIER PI PARIS CEDEX 15 PA 23 RUE LINOIS, 75724 PARIS CEDEX 15, FRANCE SN 1270-9638 J9 AEROSP SCI TECHNOL JI Aerosp. Sci. Technol. PD JUL PY 2003 VL 7 IS 5 BP 373 EP 384 DI 10.1016/S1270-9638(03)00031-2 PG 12 WC Engineering, Aerospace SC Engineering GA 716HD UT WOS:000185022000005 ER PT J AU Taylor, AC Green, LL Newman, PA Putko, MM AF Taylor, AC Green, LL Newman, PA Putko, MM TI Some advanced concepts in discrete aerodynamic sensitivity analysis SO AIAA JOURNAL LA English DT Article ID DERIVATIVES AB An efficient incremental-iterative approach for differentiating advanced flow codes is successfully demonstrated on a two-dimensional inviscid model problem. The method employs the reverse-mode capability of the automatic-differentiation software tool ADIFOR 3.0 and is proven to yield accurate first-order aerodynamic sensitivity derivatives. A substantial reduction in CPU time and computer memory is demonstrated in comparison with results from a straightforward, black-box reverse-mode application of ADIFOR 3.0 to the same flow code. An ADIFOR-assisted procedure for accurate second-order aerodynamic sensitivity derivatives is successfully verified on an inviscid transonic lifting airfoil example problem. The method requires that first-order derivatives are Calculated first using both the forward (direct) and reverse (adjoint) procedures; then, a very efficient noniterative calculation of all second-order derivatives can be accomplished. Accurate second derivatives (i.e., the complete Hessian matrices) of lift, wave drag, and pitching-moment coefficients are calculated with respect to geometric shape, angle of attack, and freestream Mach number. C1 Old Dominion Univ, Dept Mech Engn, Norfolk, VA 23529 USA. NASA, Langley Res Ctr, Multidisciplinary Optimizat Branch, Hampton, VA 23681 USA. RP Taylor, AC (reprint author), Old Dominion Univ, Dept Mech Engn, Norfolk, VA 23529 USA. NR 13 TC 10 Z9 11 U1 0 U2 1 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 JUL PY 2003 VL 41 IS 7 BP 1224 EP 1229 DI 10.2514/2.2085 PG 6 WC Engineering, Aerospace SC Engineering GA 698GR UT WOS:000183990800002 ER PT J AU Vondrak, RR Crider, DH AF Vondrak, RR Crider, DH TI Ice at the lunar poles - That the moon harbors ice at high latitudes is well known. The source of that water, however, may come as something of a surprise SO AMERICAN SCIENTIST LA English DT Article ID SOLAR-WIND C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Vondrak, RR (reprint author), NASA, Goddard Space Flight Ctr, Code 690, Greenbelt, MD 20771 USA. RI Hurley, Dana/F-4488-2015 OI Hurley, Dana/0000-0003-1052-1494 NR 10 TC 15 Z9 15 U1 0 U2 2 PU SIGMA XI-SCI RES SOC PI RES TRIANGLE PK PA PO BOX 13975, RES TRIANGLE PK, NC 27709 USA SN 0003-0996 J9 AM SCI JI Am. Scientist PD JUL-AUG PY 2003 VL 91 IS 4 BP 322 EP 329 DI 10.1511/2003.26.867 PG 8 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 689LU UT WOS:000183495300016 ER PT J AU Cullings, KW New, MH Makhija, S Parker, VT AF Cullings, KW New, MH Makhija, S Parker, VT TI Effects of litter addition on ectomycorrhizal associates of a lodgepole pine (Pinus contorta) stand in Yellowstone National Park SO APPLIED AND ENVIRONMENTAL MICROBIOLOGY LA English DT Article ID ELEMENTAL ORGANIC-ANALYSIS; MYCORRHIZAL FUNGI; SEQUENCE DATABASE; HUMUS LAYERS; SCOTS PINE; FOREST; DIVERSITY; NITROGEN; FERTILIZATION; SUCCESSION AB Increasing soil nutrients through litter manipulation, pollution, or fertilization can adversely affect ectomycorrhizal (EM) communities by inhibiting fungal growth. In this study, we used molecular genetic methods to determine the effects of litter addition on the EM community of a Pinus contorta stand in Yellowstone National Park that regenerated after a stand-replacing fire. Two controls were used; in unmodified control plots nothing was added to the soil, and in perlite plots perlite, a chemically neutral substance, was added to maintain soil moisture and temperature at levels similar to those under litter. We found that (i) species richness did not change significantly following perlite addition (2.6 +/- 0.3 species/core in control plots, compared with 2.3 +/- 0.3 species/core in perlite plots) but decreased significantly (P < 0.05) following litter addition (1.8 +/- 0.3 species/core); (ii) EM infection was not affected by the addition of perlite but increased significantly (P < 0.001) in response to litter addition, and the increase occurred only in the upper soil layer, directly adjacent to the added litter; and (iii) Suillus granulatus, Wilcoxina mikolae, and agaricoid DD were the dominant organisms in controls, but the levels of W. mikolde and agaricoid DD decreased significantly in response to both perlite and litter addition. The relative levels of S. granulatus and a fourth fungus, Cortinariaceae species 2, increased significantly (P < 0.01 and P < 0.05, respectively) following litter addition. Thus, litter addition resulted in some negative effects that may be attributable to moisture-temperature relationships rather than to the increased nutrients associated with litter. Some species respond positively to litter addition, indicating that there are differences in their physiologies. Hence, changes in the EM community induced by litter accumulation also may affect ecosystem function. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. San Francisco State Univ, Dept Biol, San Francisco, CA 94132 USA. RP Cullings, KW (reprint author), NASA, Ames Res Ctr, Mountain View, CA 94035 USA. NR 47 TC 30 Z9 33 U1 1 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 JUL PY 2003 VL 69 IS 7 BP 3772 EP 3776 DI 10.1128/AEM.69.7.3772-3776.2003 PG 5 WC Biotechnology & Applied Microbiology; Microbiology SC Biotechnology & Applied Microbiology; Microbiology GA 699XM UT WOS:000184082100011 PM 12839743 ER PT J AU Kloepfer, JA Mielke, RE Wong, MS Nealson, KH Stucky, G Nadeau, JL AF Kloepfer, JA Mielke, RE Wong, MS Nealson, KH Stucky, G Nadeau, JL TI Quantum dots as strain- and metabolism-specific microbiological labels SO APPLIED AND ENVIRONMENTAL MICROBIOLOGY LA English DT Article ID CDSE NANOCRYSTALS; GENE-EXPRESSION; TRANSFERRIN; LECTINS; GROWTH; IRON AB Biologically conjugated quantum dots (QDs) have shown great promise as multiwavelength fluorescent labels for on-chip bioassays and eukaryotic cells. However, use of these photoluminescent nanocrystals in bacteria has not previously been reported, and their large size (3 to 10 nm) makes it unclear whether they inhibit bacterial recognition of attached molecules and whether they are able to pass through bacterial cell walls. Here we describe the use of conjugated CdSe QDs for strain- and metabolism-specific microbial labeling in a wide variety of bacteria and fungi, and our analysis was geared toward using receptors for a conjugated biomolecule that are present and active on the organism's surface. While cell surface molecules, such as glycoproteins, make excellent targets for conjugated QDs, internal labeling is inconsistent and leads to large spectral shifts compared with the original fluorescence, suggesting that there is breakup or dissolution of the QDs. Transmission electron microscopy of whole mounts and thin sections confirmed that bacteria are able to extract Cd and Se from QDs in a fashion dependent upon the QD surface conjugate. C1 CALTECH, Jet Prop Lab, Ctr Life Detect, Pasadena, CA 91125 USA. Univ Calif Santa Barbara, Dept Chem & Biochem, Santa Barbara, CA 93106 USA. Univ So Calif, Dept Earth Sci, Los Angeles, CA 90089 USA. RP Nadeau, JL (reprint author), CALTECH, Jet Prop Lab, Ctr Life Detect, Mail Code 183-301,4800 Oak Grove Dr, Pasadena, CA 91125 USA. RI Wong, Michael/F-9286-2010 OI Wong, Michael/0000-0002-3652-3378 NR 30 TC 141 Z9 148 U1 0 U2 25 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 JUL PY 2003 VL 69 IS 7 BP 4205 EP 4213 DI 10.1128/AEM.69.7.4205-4213.2003 PG 9 WC Biotechnology & Applied Microbiology; Microbiology SC Biotechnology & Applied Microbiology; Microbiology GA 699XM UT WOS:000184082100069 PM 12839801 ER PT J AU Troy, M Chanan, G AF Troy, M Chanan, G TI Diffraction effects from giant segmented-mirror telescopes SO APPLIED OPTICS LA English DT Article ID ADAPTIVE OPTICS; EXTRASOLAR PLANETS AB Ultrahigh contrast imaging with giant segmented-mirror telescopes will involve light levels of order 10(-6) times that of the central diffraction spike or less. At these levels it is important to quantify accurately various diffraction effects, including segmentation geometry, intersegment gaps, obscuration by the secondary mirror and its supports, and segment alignment and figure errors. We describe an accurate method for performing such calculations and present preliminary results in the context of the California Extremely Large Telescope. (C) 2003 Optical Society of America. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Calif Irvine, Dept Phys & Astron, Irvine, CA 92697 USA. RP Troy, M (reprint author), CALTECH, Jet Prop Lab, M-S 306-388,4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM mtroy@jpl.nasa.gov NR 12 TC 17 Z9 19 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 JUL 1 PY 2003 VL 42 IS 19 BP 3745 EP 3753 DI 10.1364/AO.42.003745 PG 9 WC Optics SC Optics GA 696RU UT WOS:000183901700006 PM 12868809 ER PT J AU Huang, NE Wu, ML Qu, WD Long, SR Shen, SSP AF Huang, NE Wu, ML Qu, WD Long, SR Shen, SSP TI Applications of Hilbert-Huang transform to non-stationary financial time series analysis SO APPLIED STOCHASTIC MODELS IN BUSINESS AND INDUSTRY LA English DT Article DE Hilbert-Huang transform (HHT); empirical mode decomposition (EMD); financial time series; non-linear; non-stationary; data analysis; Hilbert spectral analysis; volatility; stock price analysis ID SPECTRUM AB A new method, the Hilbert-Huang Transform (HHT), developed initially for natural and engineering sciences has now been applied to financial data. The HHT method is specially developed for analysing non-linear and non-stationary data. The method consists of two parts: (1) the empirical mode decomposition (EMD), and (2) the Hilbert spectral analysis. The key part of the method is the first step, the EMD, with which any complicated data set can be decomposed into a finite and often small number of intrinsic mode functions (IMF). An IMF is defined here as any function having the same number of zero-crossing and extrema, and also having symmetric envelopes defined by the local maxima, and minima respectively. The IMF also thus admits well-behaved Hilbert transforms. This decomposition method is adaptive, and, therefore, highly efficient. Since the decomposition is based on the local characteristic time scale of the data, it is applicable to non-linear and non-stationary processes. With the Hilbert transform, the IMF yield instantaneous frequencies as functions of time that give sharp identifications of imbedded structures. The final presentation of the results is an energy-frequency-time distribution, which we designate as the Hilbert Spectrum. Comparisons with Wavelet and Fourier analyses show the new method offers much better temporal and frequency resolutions. The EMD is also useful as a filter to extract variability of different scales. In the present application, HHT has been used to examine the changeability of the market, as a measure of volatility of the market. Published in 2003 by John Wiley Sons, Ltd. C1 NASA, Goddard Space Flight Ctr, Lab Hydrospher Proc, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. CALTECH, Pasadena, CA 91125 USA. NASA, Wallops Flight Facil, Lab Hydrospher Proc, Wallops Isl, VA 23337 USA. Univ Alberta, Dept Math Sci, Edmonton, AB T6G 2G1, Canada. RP Huang, NE (reprint author), NASA, Goddard Space Flight Ctr, Lab Hydrospher Proc, Code 971, Greenbelt, MD 20771 USA. RI Long, Steven/D-7248-2012 NR 23 TC 168 Z9 204 U1 5 U2 57 PU JOHN WILEY & SONS LTD PI CHICHESTER PA THE ATRIUM, SOUTHERN GATE, CHICHESTER PO19 8SQ, W SUSSEX, ENGLAND SN 1524-1904 J9 APPL STOCH MODEL BUS JI Appl. Stoch. Models. Bus. Ind. PD JUL-SEP PY 2003 VL 19 IS 3 BP 245 EP 268 DI 10.1002/asmb.501 PG 24 WC Operations Research & Management Science; Mathematics, Interdisciplinary Applications; Statistics & Probability SC Operations Research & Management Science; Mathematics GA 754PG UT WOS:000187326000007 ER PT J AU Soifer, BT Bock, JJ Marsh, K Neugebauer, G Matthews, K Egami, E Armus, L AF Soifer, BT Bock, JJ Marsh, K Neugebauer, G Matthews, K Egami, E Armus, L TI High spatial resolution mid-infrared observations of three Seyfert galaxies SO ASTRONOMICAL JOURNAL LA English DT Article DE galaxies : individual (NGC 1275, NGC 4151, NGC 7469); galaxies : Seyfert; infrared radiation ID DISTRIBUTIONS; NGC-4151; EMISSION; NUCLEUS AB Images at 12.5 mum of nuclei of three nearby Seyfert galaxies-NGC 1275, NGC 4151, and NGC 7469-have been obtained with the 10 m Keck Telescope. NGC 7469 is resolved and deconvolution delineates a structure (<0."04) x 0."08, or less than 13 x 26 pc at a position angle of 135&DEG;. From a comparison with structure seen at millimeter wavelengths, this structure is interpreted as a disk aligned with the molecular gas in the central few hundred parsecs of the galaxy. NGC 1275 and NGC 4151 are not resolved; limits on the sizes of these nuclei are 0."08 and 0."16, corresponding to physical spatial scales of 28 and 10 pc. The lower limits to the brightness temperatures implied by these size limits and the measured flux densities are within &SIM;50 K of the 12-25 μm color temperatures of these systems, as inferred from IRAS observations. The angular size limits are within a factor of 2 of the sizes required to spatially resolve thermal emission from dust heated by a central luminosity source. These sizes preclude significant contributions to the nuclear infrared emission from star-forming regions. C1 CALTECH, Caltech Opt Observ, Pasadena, CA 91125 USA. CALTECH, SIRTF Sci Ctr, Pasadena, CA 91125 USA. CALTECH, Div Phys Math & Astron, Pasadena, CA 91125 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. CALTECH, IPAC, Pasadena, CA 91125 USA. RP Soifer, BT (reprint author), CALTECH, Caltech Opt Observ, MS 320-47, Pasadena, CA 91125 USA. NR 24 TC 36 Z9 36 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 JUL PY 2003 VL 126 IS 1 BP 143 EP 152 DI 10.1086/375647 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 696UG UT WOS:000183905500014 ER PT J AU Immler, S Brandt, WN Vignali, C Baueer, FE Crenshaw, DM Feldmeier, JJ Kraemer, SB AF Immler, S Brandt, WN Vignali, C Baueer, FE Crenshaw, DM Feldmeier, JJ Kraemer, SB TI Probing the complex and variable X-ray absorption of Markarian 6 with XMM-Newton SO ASTRONOMICAL JOURNAL LA English DT Article DE galaxies : individual (Markarian 6); galaxies : Seyfert; X-rays ID ACTIVE GALACTIC NUCLEI; NARROW-LINE REGION; K-ALPHA LINE; BEPPOSAX OBSERVATION; SEYFERT-2 GALAXIES; VARIABILITY; NGC-4151; EMISSION; RADIO; MRK-766 AB We report on an X-ray observation of the Seyfert 1.5 galaxy Mrk 6 obtained with the EPIC instruments on board XMM-Newton. Archival BeppoSAX Phoswich Detection System data from 18-120 keV were also used to constrain the underlying hard power-law continuum. The results from our spectral analyses generally favor a double partial-covering model, although other spectral models, such as absorption by a mixture of partially ionized and neutral gas, cannot be firmly ruled out. Our best-fitting model consists of a power law with a photon index of Gamma = 1.81(-0.20)(+0.22) and partial covering with large column densities up to N-H similar to 10(23) cm(-2). We also detect a narrow emission line consistent with Fe Kalpha fluorescence at 6.45(-0.04)(+0.03) keV with an equivalent width of 93(-20)(+26) eV. Joint analyses of XMM-Newton, ASCA, and BeppoSAX data further provide evidence for both spectral variability (a factor of similar to2 change in absorbing column) and absorption-corrected flux variations (by similar to60%) during the similar to4 yr period probed by the observations. C1 Penn State Univ, Dept Astron & Astrophys, Davey Lab 525, University Pk, PA 16802 USA. Georgia State Univ, Dept Phys & Astron, Atlanta, GA 30303 USA. Case Western Reserve Univ, Dept Astron, Cleveland, OH 44106 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Catholic Univ Amer, Greenbelt, MD 20771 USA. RP Penn State Univ, Dept Astron & Astrophys, Davey Lab 525, University Pk, PA 16802 USA. RI Vignali, Cristian/J-4974-2012; Brandt, William/N-2844-2015; OI Vignali, Cristian/0000-0002-8853-9611; Brandt, William/0000-0002-0167-2453; Feldmeier, John/0000-0003-2908-2620 NR 32 TC 23 Z9 23 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-6256 EI 1538-3881 J9 ASTRON J JI Astron. J. PD JUL PY 2003 VL 126 IS 1 BP 153 EP 157 DI 10.1086/375652 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 696UG UT WOS:000183905500015 ER PT J AU Lai, SP Velusamy, T Langer, WD Kuiper, TBH AF Lai, SP Velusamy, T Langer, WD Kuiper, TBH TI The physical and chemical status of pre-protostellar core B68 SO ASTRONOMICAL JOURNAL LA English DT Article DE ISM : abundances; ISM : globules; ISM : individual (B68); ISM : molecules; stars : formation ID MASS STAR-FORMATION; DARK CLOUD CORES; AMBIPOLAR DIFFUSION; DENSE CORES; AMMONIA; BARNARD-68; CCS; PREPROTOSTELLAR; PROTOSTARS; COLLAPSE AB We have investigated the physical and chemical status of the pre-protostellar core B68. A previous extinction study suggested that the density pro. le of B68 is remarkably consistent with a Bonnor-Ebert sphere with 2.1 M-. at 16 K. We mapped B68 in C3H2, CCS, and NH3 with the Deep Space Network (DSN) 70 m telescope at Goldstone. Our results show that the NH3 peak coincides with the dust continuum peak, whereas CCS and C3H2 are offset from the NH3 and dust peaks. The B68 chemical structure is consistent with that seen in other such pre-protostellar cores (L1498 and L1544) and is explained by time-dependent chemical models that include depletion. We measured the kinetic temperature of B68 with NH3 ( 1, 1) and ( 2, 2) spectra obtained with a DSN 34 m telescope. We find that the kinetic temperature of B68 is only 11K, which is significantly lower than that previously assumed. We also derive the nonthermal line width in B68 and show that B68 is thermally dominated with little contribution from turbulence support ( less than 10%). We consider a modified Bonnor-Ebert sphere to include effects of turbulence and magnetic fields and use it to constrain the uncertainties in its distance determination. We conclude that the distance to B68 is similar to95 pc with a corresponding mass of similar to1.0 M-.. If some magnetic field is present, it can be further away ( beyond similar to100 pc) and still satisfy the density structure of a Bonnor-Ebert sphere. The sulfur (CS and CCS) and carbon chain (C3H2) molecules are heavily depleted in B68 and do not trace the dense interior region. We see some evidence for depletion of NH3 at the core center roughly on a scale similar to that of N2H+. Our observations do not preclude any instability such as the onset of collapse, or slow contraction, occurring in the center of the core, which cannot be resolved with our beam size (45"). C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Lai, SP (reprint author), CALTECH, Jet Prop Lab, MS 169-506, Pasadena, CA 91109 USA. NR 40 TC 30 Z9 30 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 JUL PY 2003 VL 126 IS 1 BP 311 EP 318 DI 10.1086/375458 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 696UG UT WOS:000183905500027 ER PT J AU Schwartz, RD Greene, TP AF Schwartz, RD Greene, TP TI High spectral resolution H-2 measurements of Herbig-Haro objects 38, 46/47, and 120 SO ASTRONOMICAL JOURNAL LA English DT Article DE ISM : Herbig-Haro objects; ISM : jets and outflows ID MOLECULAR-HYDROGEN EMISSION; NEAR-INFRARED OBSERVATIONS; YOUNG STARS; EXCITING STARS; ENERGY-SOURCES; GUM NEBULA; HH 46/47; FE II; OUTFLOWS; JETS AB We report high spectral resolution (R similar or equal to 20,000) measurements of the H-2 1 - 0 S(1) line in Herbig-Haro objects 38, 46/47, and 120. The long-slit spectra reveal complex velocity structure with evidence for bow-shock structures, as well as prompt entrainment and shock heating of ambient molecular gas. Individual knots within HH 38 show distinct double-peaked velocity structure, consistent with that expected from spatially unresolved bow shocks. A portion of the HH 47A bow shock is resolved in our measurements, and the kinematics of the H-2 trace closely that found for Halpha emission. The evidence indicates that the preshock medium for HH 47A that formed in the wake of a previous ejection contains molecular clumps. The HH 46C jet A feature in the HH 46/47 counterflow is suggestive of a bow shock emerging from near the base of the flow, with H-2 emission arising from ambient cloud material excited in the oblique flanks of the bow shock. HH 46F is situated downstream at the boundary between the ovoid cavity and the ambient cloud material, and represents either entrainment by a stellar wind that fills the cavity or entrainment in the far wing of a giant bow shock. For HH 120, the H-2 velocity results also corroborate those found from atomic emission, and there is substantial evidence that the preshock medium is inhomogeneous, producing clumps of H-2 emission on the wings of a bow shock that has an apex at HH 120A. C1 Univ Missouri, Dept Phys & Astron, St Louis, MO 63121 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Univ Missouri, Dept Phys & Astron, 8001 Nat Bridge Rd, St Louis, MO 63121 USA. EM schwartz@umsl.edu; thomas.p.greene@nasa.gov NR 37 TC 14 Z9 14 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-6256 EI 1538-3881 J9 ASTRON J JI Astron. J. PD JUL PY 2003 VL 126 IS 1 BP 339 EP 347 DI 10.1086/375760 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 696UG UT WOS:000183905500030 ER PT J AU Clampin, M Krist, JE Ardila, DR Golimowski, DA Hartig, GF Ford, HC Illingworth, GD Bartko, F Benitez, N Blakeslee, JP Bouwens, RJ Broadhurst, TJ Brown, RA Burrows, CJ Cheng, ES Cross, NJG Feldman, PD Franx, M Gronwall, C Infante, L Kimble, RA Lesser, MP Martel, AR Menanteau, F Meurer, GR Miley, GK Postman, M Rosati, P Sirianni, M Sparks, WB Tran, HD Tsvetanov, ZI White, RL Zheng, W AF Clampin, M Krist, JE Ardila, DR Golimowski, DA Hartig, GF Ford, HC Illingworth, GD Bartko, F Benitez, N Blakeslee, JP Bouwens, RJ Broadhurst, TJ Brown, RA Burrows, CJ Cheng, ES Cross, NJG Feldman, PD Franx, M Gronwall, C Infante, L Kimble, RA Lesser, MP Martel, AR Menanteau, F Meurer, GR Miley, GK Postman, M Rosati, P Sirianni, M Sparks, WB Tran, HD Tsvetanov, ZI White, RL Zheng, W TI Hubble Space Telescope ACS coronagraphic imaging of the circumstellar disk around HD 141569A SO ASTRONOMICAL JOURNAL LA English DT Article DE circumstellar matter; stars : individual (HD 141569A); stars : pre-main-sequence ID DYNAMICS; HD141569; EMISSION; SOUTHERN; STARS; DUST AB Multicolor coronagraphic images of the circumstellar disk around HD 141569A have been obtained with the Hubble Space Telescope Advanced Camera for Surveys. The B, V, and I images show that the disk's previously described multiple-ring structure is actually a continuous distribution of dust with a tightly wound spiral structure. Extending from the disk are two, more open spiral arms, one of which appears to reach the nearby binary star HD 141569BC. Diffuse dust is seen up to 1200 AU from HD 141569A. Although planets may exist in the inner region of the disk, tidal interaction with HD 141569BC seems more likely to be the cause of these phenomena. The disk appears redder than the star ( B - V = 0.21 and V - I = 0.25), and its color is spatially uniform. A scattering asymmetry factor of g = 0.25 - 0.35 is derived. The azimuthal density distribution is asymmetric, varying by a factor of similar to3 at some radii. C1 Space Telescope Sci Inst, Baltimore, MD 21218 USA. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. Univ Calif Santa Cruz, Lick Observ, Santa Cruz, CA 95064 USA. Bartko Sci & Technol, Mead, CO 80542 USA. Hebrew Univ Jerusalem, Racah Inst Phys, IL-91904 Jerusalem, Israel. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Sterrewacht Leiden, NL-2300 RA Leiden, Netherlands. Pontificia Univ Catolica Chile, Dept Astron & Astrofis, Santiago, Chile. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. European So Observ, D-85748 Garching, Germany. RP Clampin, M (reprint author), Space Telescope Sci Inst, 3700 San Martin Dr, Baltimore, MD 21218 USA. RI White, Richard/A-8143-2012; Kimble, Randy/D-5317-2012; OI Benitez, Narciso/0000-0002-0403-7455; Blakeslee, John/0000-0002-5213-3548 NR 28 TC 137 Z9 137 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 JUL PY 2003 VL 126 IS 1 BP 385 EP 392 DI 10.1086/375460 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 696UG UT WOS:000183905500034 ER PT J AU Bernard-Salas, J Pottasch, SR Wesselius, PR Feibelman, WA AF Bernard-Salas, J Pottasch, SR Wesselius, PR Feibelman, WA TI Abundances of Planetary Nebulae BD+30 3639 and NGC 6543 SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE ISM : abundances; Planetary Nebulae : individual : BD+30 3639, NGC 6543; infrared : ISM; ISM : lines and bands ID ULTRAVIOLET-SPECTRA; EMISSION-LINES; ISO; STARS; BD+30-DEGREES-3639; NGC-6826; HALOES; OXYGEN AB Infrared spectra taken with the Short Wavelength Spectrometer on board ISO and UV observations with IUE of planetary nebulae BD+303639 and NGC6543 are presented. The extinction derived using infrared lines for BD+303639 is EB-V = 0.34, slightly higher than previous determinations. For NGC6543 the extinction found from the hydrogen lines is EB-V = 0.07. Infrared, optical and ultraviolet data have been used to derive the physical parameters of the nebula. BD+303639 has an average T-e = 8500 K and Ne = 11 000 cm(-3). In the case of NGC6543 a T-e = 8200 K and N-e = 5000 cm(-3) have been found, in agreement with previous determinations. The element abundances have been derived and compared to those found in the Sun and O, B stars. This comparison gives a hint of the mass of the progenitor stars from which they evolved. C1 Univ Groningen, SRON, Natl Inst Space Res, NL-9700 AV Groningen, Netherlands. Univ Groningen, Kapteyn Astron Inst, NL-9700 AV Groningen, Netherlands. NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. RP Univ Groningen, SRON, Natl Inst Space Res, POB 800, NL-9700 AV Groningen, Netherlands. EM J.Bernard@sron.rug.nl NR 30 TC 23 Z9 23 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 1432-0746 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD JUL PY 2003 VL 406 IS 1 BP 165 EP 174 DI 10.1051/0004-6361:20030777 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 700EJ UT WOS:000184099400025 ER PT J AU in 't Zand, JJM Hulleman, F Markwardt, CB Mendez, M Kuulkers, E Cornelisse, R Heise, J Strohmayer, TE Verbunt, F AF in 't Zand, JJM Hulleman, F Markwardt, CB Mendez, M Kuulkers, E Cornelisse, R Heise, J Strohmayer, TE Verbunt, F TI Bursts, eclipses, dips and a refined position for the luminous low-mass X-ray binary in the globular cluster Terzan 6 SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE accretion, accretion disks; globular clusters : individual : Terzan 6; X-rays : binaries; X-rays : bursts; X-rays : individual : GRS 1747-312 ID DISC INSTABILITY MODEL; GALACTIC-CENTER; MILLISECOND PULSATIONS; TIMING-EXPLORER; ORBITAL PERIOD; NEUTRON STARS; DWARF NOVAE; DISCOVERY; TRANSIENTS; BEPPOSAX AB GRS 1747-312 is a bright transient X-ray source in the globular cluster Terzan 6 with quasi-periodic outbursts approximately every 4.5 months. We carried out 2-60 keV target-of-opportunity observations during eight outbursts with the Proportional Counter Array on the RXTE satellite, for a total exposure time of 301 ks, and detect the first unambiguous thermonuclear X-ray bursts from this source. This identifies the compact accretor in this binary as a neutron star. The neutron star identification implies that twelve out of thirteen luminous (above 1036 erg s(-1)) X-ray sources in Galactic globular clusters harbor neutron stars, with AC211's nature (in M15) remaining elusive. We observed 24 transitions of eclipses of the X-ray emitting region by the companion star and are able to improve the accuracy of the orbital period by a factor of 10(4). The period is P = 0.514980303(7) d. We do not detect a period derivative with an upper limit of \(P)over dot/P\ = 3 x 10(-8) yr(-1). Archival Chandra data were analyzed to further refine the X-ray position, and the cluster's center of gravity was re-determined from optical data resulting in a correction amounting to 2 core radii. We find that GRS 1747-312 is 0.2 +/- 0.2 core radii from the cluster center. C1 SRON, Natl Inst Space Res, NL-3584 CA Utrecht, Netherlands. Univ Utrecht, Astron Inst, NL-3508 TA Utrecht, Netherlands. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Maryland, Dept Astron, College Pk, MD 20742 USA. ESA, ESTEC, Sci Operat & Sata Syst Div, SCI SDG, NL-2201 AZ Noordwijk, Netherlands. RP SRON, Natl Inst Space Res, Sorbonnelaan 2, NL-3584 CA Utrecht, Netherlands. EM jeanz@sron.nl RI Mendez, Mariano/C-8011-2012 OI Mendez, Mariano/0000-0003-2187-2708 NR 58 TC 20 Z9 20 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 1432-0746 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD JUL PY 2003 VL 406 IS 1 BP 233 EP 243 DI 10.1051/0004-6361:20030681 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 700EJ UT WOS:000184099400032 ER PT J AU Moehler, S Landsman, WB Sweigart, AV Grundahl, F AF Moehler, S Landsman, WB Sweigart, AV Grundahl, F TI Hot HB stars in globular clusters - Physical parameters and consequences for theory - VI. The second parameter pair M 3 and M 13 SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE stars : atmospheres; stars : evolution; stars : horizontal-branch; Galaxy : globular clusters : individual : M 3; Galaxy : globular clusters : individual : M 13 ID HORIZONTAL-BRANCH STARS; OXYGEN ABUNDANCES; CCD PHOTOMETRY; HALO GIANTS; RADIATIVE LEVITATION; ALUMINUM ABUNDANCES; MASS-DISTRIBUTION; SELF-POLLUTION; WHITE-DWARFS; M13 AB We present the results of spectroscopic analyses of hot horizontal branch (HB) stars in M 13 and M 3, which form a famous "second parameter" pair. From the spectra and Stromgren photometry we derived - for the first time in M 13 - atmospheric parameters (effective temperature and surface gravity). For stars with Stromgren temperatures between 10 000 and 12 000 K we found excellent agreement between the atmospheric parameters derived from Stromgren photometry and those derived from Balmer line profile fits. However, for cooler stars there is a disagreement in the parameters derived by the two methods, for which we have no satisfactory explanation. Stars hotter than 12 000 K show evidence for helium depletion and iron enrichment, both in M 3 and M 13. Accounting for the iron enrichment substantially improves the agreement with canonical evolutionary models, although the derived gravities and masses are still somewhat too low. This remaining discrepancy may be an indication that scaled-solar metal-rich model atmospheres do not adequately represent the highly non-solar abundance ratios found in blue HB stars affected by diffusion. We discuss the effects of an enhancement in the envelope helium abundance on the atmospheric parameters of the blue HB stars, as might be caused by deep mixing on the red giant branch or primordial pollution from an earlier generation of intermediate mass asymptotic giant branch stars. C1 Inst Theoret Phys & Astrophys, Abt Astrophys, D-24098 Kiel, Germany. Univ Erlangen Nurnberg, Dr Remeis Sternwarte, Astron Inst, D-96049 Bamberg, Germany. NASA, SSAI, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Aarhus Univ, Inst Phys & Astron, DK-8000 Aarhus C, Denmark. RP Moehler, S (reprint author), Inst Theoret Phys & Astrophys, Abt Astrophys, Leibnizstr 15, D-24098 Kiel, Germany. OI Moehler, Sabine/0000-0002-4152-9643 NR 53 TC 25 Z9 25 U1 0 U2 0 PU E D P SCIENCES PI LES ULIS CEDEXA PA 7, AVE DU HOGGAR, PARC D ACTIVITES COURTABOEUF, BP 112, F-91944 LES ULIS CEDEXA, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD JUL PY 2003 VL 405 IS 1 BP 135 EP 148 DI 10.1051/0004-6361:20030622 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 689RV UT WOS:000183507500016 ER PT J AU Zhou, Y Rubinstein, R Eliason, D Cabot, W AF Zhou, Y Rubinstein, R Eliason, D Cabot, W TI Computing turbulent flows driven by Rayleigh-Taylor and Richtmyer-Meshkov instabilities SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE instabilities; stars : supernovae : general; turbulence ID ISOTROPIC TURBULENCE; ENERGY-TRANSFER; INERTIAL RANGE; CORE-COLLAPSE; SUPERNOVA; MODEL AB We develop a two-scale turbulence model for turbulent mix induced by Rayleigh-Taylor and Richtmyer-Meshkov instabilities. In this model, the large scales are dominated by production by instability mechanisms, while small scales satisfy Kolmogorov dynamics. The model allows transfer rates in the two spectral regions to be unequal. Constraints on model coefficients that permit relaxation to a unique self-similar state in free decay and self-similar growth are derived. C1 NASA, Langley Res Ctr, Computat Modeling & Simulat Branch, Hampton, VA 23681 USA. Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. RP Rubinstein, R (reprint author), NASA, Langley Res Ctr, Computat Modeling & Simulat Branch, Hampton, VA 23681 USA. NR 30 TC 3 Z9 3 U1 0 U2 1 PU E D P SCIENCES PI LES ULIS CEDEXA PA 7, AVE DU HOGGAR, PARC D ACTIVITES COURTABOEUF, BP 112, F-91944 LES ULIS CEDEXA, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD JUL PY 2003 VL 405 IS 2 BP 379 EP 386 DI 10.1051/0004-6361:20030411 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 691PY UT WOS:000183615700002 ER PT J AU McIntosh, SW Fleck, B Judge, PG AF McIntosh, SW Fleck, B Judge, PG TI Investigating the role of plasma topography on chromospheric oscillations observed by TRACE SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE Sun : chromosphere; Sun : oscillations; Sun : UV radiation ID CELL-NETWORK DISTINCTIONS; SOLAR CHROMOSPHERE; TRANSITION REGION; QUIET SUN; WAVES; ATMOSPHERE; DYNAMICS AB We present the results of an investigation into the interaction of the topographic structure of the solar chromospheric plasma with the wave modes manifesting themselves in the UV continua formed there. We show that there is a distinct correlation between the inferred plasma topography, the phase-differences between and suppression of oscillations in different levels of the solar atmosphere. We interpret these factors as evidence of interaction between the oscillations and the extended magnetic "canopy". This work is based on the analysis of joint observations made by the Solar and Heliospheric Observatory (SOHO) spacecraft and the Transition Region and Coronal Explorer (TRACE). C1 NASA, Goddard Space Flight Ctr, European Space Agcy, Res & Sci Support Dept, Greenbelt, MD 20772 USA. Natl Ctr Atmospher Res, High Altitude Observ, Boulder, CO 80307 USA. RP NASA, Goddard Space Flight Ctr, European Space Agcy, Res & Sci Support Dept, Greenbelt, MD 20772 USA. EM scott@esa.nascom.nasa.gov RI Fleck, Bernhard/C-9520-2012 NR 19 TC 31 Z9 31 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 1432-0746 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD JUL PY 2003 VL 405 IS 2 BP 769 EP 777 DI 10.1051/0004-6361:20030627 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 691PY UT WOS:000183615700041 ER PT J AU Scharwachter, J Eckart, A Pfalzner, S Moultaka, J Straubmeier, C Staguhn, JG AF Scharwachter, J Eckart, A Pfalzner, S Moultaka, J Straubmeier, C Staguhn, JG TI I Zw 1: Decomposition of the nearby QSO host SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE galaxies : individual : I Zw 1; galaxies : active; galaxies : photometry; galaxies : structure methods : observational ID ULTRALUMINOUS INFRARED GALAXIES; ACTIVE GALACTIC NUCLEI; RADIO-QUIET QUASARS; SPIRAL GALAXIES; INTERSTELLAR-MEDIUM; SEYFERT-1 GALAXIES; STANDARD STARS; MOLECULAR GAS; DARK-MATTER; I ZW-1 AB The paper presents an analysis of the nearby QSO host I Zw 1 based on new J-band imaging data, obtained with ISAAC at the Very Large Telescope (VLT) of the European Southern Observatory (ESO). As one of the best-studied QSOs with exceptional properties lying between those of QSOs, narrow-line Seyfert 1s, and ultraluminous infrared galaxies, I Zw 1 is a prime candidate for a detailed case study of a QSO host. With its high angular resolution and sensitivity, the new J-band image provides strong evidence for an interaction between I Zw 1 and the western companion galaxy. We present a procedure for subtracting the QSO nucleus from the I Zw 1 image to obtain an undisturbed view on the underlying host galaxy. Based on the derived surface brightness profile and the gas rotation curve, the host is classified as a high-surface-brightness Freeman type I galaxy with a central disk surface brightness significantly larger than that of normal spirals. The surface-brightness profile is decomposed into a Plummer bulge and a Kuzmin disk with similar luminosities and a bulge-to-disk scale length ratio of 0.29, comparable to that of nearby spiral hosts with active galactic nuclei (AGN). Different models for the decomposition of the gas rotation curve are discussed. The resulting J-band mass-to-light ratio (M/L) of (0.7 +/- 0.4) M-./L-. for the disk component suggests a mean solar-type stellar population with a tendency towards young stars. The bulge exhibits a lower M/L of (0.4 +/- 0.2) M-./L-., which supports previous findings of enhanced starburst activity in the nuclear and circumnuclear region. C1 Univ Cologne, Inst Phys 1, D-50937 Cologne, Germany. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Scharwachter, J (reprint author), Univ Cologne, Inst Phys 1, Zulpicher Str 77, D-50937 Cologne, Germany. NR 50 TC 8 Z9 8 U1 0 U2 0 PU E D P SCIENCES PI LES ULIS CEDEXA PA 7, AVE DU HOGGAR, PARC D ACTIVITES COURTABOEUF, BP 112, F-91944 LES ULIS CEDEXA, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD JUL PY 2003 VL 405 IS 3 BP 959 EP 967 DI 10.1051/0004-6361:20030678 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 696HF UT WOS:000183881000018 ER PT J AU Zsargo, J Fullerton, AW Lehner, N Massa, D AF Zsargo, J Fullerton, AW Lehner, N Massa, D TI A search for OVI in the winds of B-type stars SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE stars : early-type; stars : mass-loss; ultraviolet : general ID X-RAY-EMISSION; DRIVEN STELLAR WINDS; OB RUNAWAY STARS; SUPER-GIANTS; HOT STAR; VARIABILITY; SUPERGIANTS; IONIZATION; LINES; HALO AB We have conducted a survey of FUSE spectra of 235 Galactic B-type stars in order to determine the boundaries in the H-R diagram for the production of the superion O VI in their winds. By comparing the locations and morphology of otherwise unidentified absorption features in the vicinity of the O VI resonance doublet with the bona fide wind profiles seen in archival IUE spectra of the resonance lines of N V, Si IV and C IV, we were able to detect blueshifted O VI lines in the spectra of giant and supergiant stars with temperature classes as late as B1. No features attributable to O VI were detected in dwarfs later than B0, or in stars of any luminosity class later than B1, although our ability to recognize weak absorption features in these stars is severely restricted by blending with photospheric and interstellar features. We discuss evidence that the ratio of the ion fractions of O VI and N V is substantially different in the winds of early B-type stars than O-type stars. C1 Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. Univ Victoria, Dept Phys & Astron, Victoria, BC V8W 3P6, Canada. NASA, Goddard Space Flight Ctr, SGT Inc, Greenbelt, MD 20771 USA. RP Zsargo, J (reprint author), Johns Hopkins Univ, Dept Phys & Astron, 3400 N Charles St, Baltimore, MD 21218 USA. NR 45 TC 3 Z9 4 U1 0 U2 0 PU E D P SCIENCES PI LES ULIS CEDEXA PA 7, AVE DU HOGGAR, PARC D ACTIVITES COURTABOEUF, BP 112, F-91944 LES ULIS CEDEXA, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD JUL PY 2003 VL 405 IS 3 BP 1043 EP 1056 DI 10.1051/0004-6361:20030601 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 696HF UT WOS:000183881000027 ER PT J AU Kaasalainen, M Kwiatkowski, T Abe, M Piironen, J Nakamura, T Ohba, Y Dermawan, B Farnham, T Colas, F Lowry, S Weissman, P Whiteley, RJ Tholen, DJ Larson, SM Yoshikawa, M Toth, I Velichko, FP AF Kaasalainen, M Kwiatkowski, T Abe, M Piironen, J Nakamura, T Ohba, Y Dermawan, B Farnham, T Colas, F Lowry, S Weissman, P Whiteley, RJ Tholen, DJ Larson, SM Yoshikawa, M Toth, I Velichko, FP TI CCD photometry and model of MUSES-C target (25143) 1998 SF36 SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE solar system : minor planets, asteroids; techniques : photometric; methods : numerical ID ASTEROIDS AB We present photometric observations of the near-Earth asteroid ( 25143) 1998 SF36 from the 2001 apparition campaign, and we discuss the corresponding physical model. The asteroid's photometric behaviour is consistent with an S-type object, it has a retrograde pole at lambda = 355degrees; beta = - 84degrees +/- 5 degrees, and its sidereal rotation period is P = 12.132 +/- 0.0005 hours. 1998 SF36 is elongated, with rough global dimension ratios a/b = 2.0, b/c = 1.3, but the elongation is not due to a bifurcated shape. The surface is not likely to contain major concavities. No significant albedo variegation was detected. C1 Univ Helsinki, Observ, FIN-00014 Helsinki, Finland. Adam Mickiewicz Univ Poznan, Astron Observ, PL-60286 Poznan, Poland. Inst Space & Astronaut Sci, Kanagawa 2298510, Japan. Natl Astron Observ, Tokyo 1818588, Japan. Univ Tokyo, Sch Sci, Tokyo 1130033, Japan. Univ Texas, Dept Astron, Austin, TX 78712 USA. Observ Paris, IMCCE, F-75014 Paris, France. CALTECH, Jet Prop Lab, Div Earth & Space Sci, Pasadena, CA 91109 USA. Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. Univ Hawaii, Inst Astron, Honolulu, HI 96822 USA. Konkoly Observ Budapest, H-1525 Budapest, Hungary. Kharkiv Natl Univ, Astron Observ, UA-61022 Kharkov, Ukraine. RP Kaasalainen, M (reprint author), Univ Helsinki, Observ, POB 14, FIN-00014 Helsinki, Finland. RI Kaasalainen, Mikko/G-4236-2014 NR 11 TC 33 Z9 33 U1 0 U2 0 PU E D P SCIENCES PI LES ULIS CEDEXA PA 7, AVE DU HOGGAR, PARC D ACTIVITES COURTABOEUF, BP 112, F-91944 LES ULIS CEDEXA, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD JUL PY 2003 VL 405 IS 3 BP L29 EP L32 DI 10.1051/0004-6361:20030819 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 696HF UT WOS:000183881000002 ER PT J AU Rol, E Wijers, RAMJ Fynbo, JPU Hjorth, J Gorosabel, J Egholm, MP Ceron, JMC Castro-Tirado, AJ Kaper, L Masetti, N Palazzi, E Pian, E Tanvir, N Vreeswijk, P Kouveliotou, C Moller, P Pedersen, H Fruchter, AS Rhoads, J Burud, I Salamanca, I Van den Heuvel, EPJ AF Rol, E Wijers, RAMJ Fynbo, JPU Hjorth, J Gorosabel, J Egholm, MP Ceron, JMC Castro-Tirado, AJ Kaper, L Masetti, N Palazzi, E Pian, E Tanvir, N Vreeswijk, P Kouveliotou, C Moller, P Pedersen, H Fruchter, AS Rhoads, J Burud, I Salamanca, I Van den Heuvel, EPJ TI Variable polarization in the optical afterglow of GRB021004 SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE gamma rays : bursts; polarization; radiation mechanisms : non-thermal ID GAMMA-RAY BURSTS; LINEAR-POLARIZATION; LIGHT CURVES; GRB-021004; VARIABILITY; GRB-990510; GRB-020405; EMISSION AB We present polarimetric observations of the afterglow of gamma-ray burst (GRB) 021004, obtained with the Nordic Optical Telescope ( NOT) and the Very Large Telescope (VLT) between 8 and 17 hours after the burst. Comparison among the observations shows a 45 degree change in the position angle from 9 hours after the burst to 16 hours after the burst, and comparison with published data from later epochs even shows a 90 degree change between 9 and 89 hours after the burst. The degree of linear polarization shows a marginal change, but is also consistent with being constant in time. In the context of currently available models for changes in the polarization of GRBs, a homogeneous jet with an early break time of t(b) approximate to 1 day provides a good explanation of our data. The break time is a factor 2 to 6 earlier than has been found from the analysis of the optical light curve. The change in the position angle of the polarization rules out a structured jet model for the GRB. C1 Univ Amsterdam, Astron Inst, NL-1098 SJ Amsterdam, Netherlands. Univ Aarhus, Dept Phys & Astron, DK-8000 Aarhus, Denmark. Univ Copenhagen, Astron Observ, DK-2100 Copenhagen, Denmark. Inst Astrofis Andalucia, Granada 18008, Spain. Space Telescope Sci Inst, Baltimore, MD 21218 USA. Nord Opt Telescope, Tenerife 38700, Spain. Real Inst & Observ Armada, Secc Astron, Cadiz 11110, Spain. CNR, Ist Astrofis Spaziale & Fis Cosm, Sez Bologna, I-40129 Bologna, Italy. Astron Observ Trieste, INAF, I-34131 Trieste, Italy. Univ Hertfordshire, Dept Phys Sci, Hatfield AL10 9AB, Herts, England. European So Observ, Santiago 19, Chile. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. European So Observ, D-85748 Garching, Germany. RP Rol, E (reprint author), Univ Amsterdam, Astron Inst, Kruislaan 403, NL-1098 SJ Amsterdam, Netherlands. RI Hjorth, Jens/M-5787-2014; Palazzi, Eliana/N-4746-2015; OI Hjorth, Jens/0000-0002-4571-2306; Wijers, Ralph/0000-0002-3101-1808; Palazzi, Eliana/0000-0002-8691-7666; Masetti, Nicola/0000-0001-9487-7740 NR 45 TC 35 Z9 35 U1 0 U2 1 PU E D P SCIENCES PI LES ULIS CEDEXA PA 7, AVE DU HOGGAR, PARC D ACTIVITES COURTABOEUF, BP 112, F-91944 LES ULIS CEDEXA, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD JUL PY 2003 VL 405 IS 3 BP L23 EP L27 DI 10.1051/0004-6361:20030731 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 696HF UT WOS:000183881000001 ER PT J AU McDowell, JC Clements, DL Lamb, SA Shaked, S Hearn, NC Colina, L Mundell, C Borne, K Baker, AC Arribas, S AF McDowell, JC Clements, DL Lamb, SA Shaked, S Hearn, NC Colina, L Mundell, C Borne, K Baker, AC Arribas, S TI Chandra observations of extended X-ray emission in Arp 220 SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : individual (Arp 220); galaxies : interactions; galaxies : starburst; X-rays : galaxies ID ULTRALUMINOUS IRAS GALAXIES; ARP 220; INFRARED GALAXIES; STARBURST GALAXY; STAR-FORMATION; RING GALAXIES; IC 4553; H-I; MARKARIAN-231; MORPHOLOGIES AB We resolve the extended X-ray emission from the prototypical ultraluminous infrared galaxy Arp 220. Extended, faint, edge-brightened, soft X-ray lobes outside the optical galaxy are observed to a distance of 10-15 kpc on each side of the nuclear region. Bright plumes inside the optical isophotes coincide with the optical line emission and extend 11 kpc from end to end across the nucleus. The data for the plumes cannot be fitted by a single-temperature plasma and display a range of temperatures from 0.2 to 1 keV. The plumes emerge from bright, diffuse circumnuclear emission in the inner 3 kpc centered on the Halpha peak, which is displaced from the radio nuclei. There is a close morphological correspondence between the Halpha and soft X-ray emission on all spatial scales. We interpret the plumes as a starburst-driven superwind and discuss two interpretations of the emission from the lobes in the context of simulations of the merger dynamics of Arp 220. C1 Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ London Imperial Coll Sci Technol & Med, Dept Phys, London SW7 2BW, England. Univ Illinois, Ctr Theoret Astrophys, Dept Phys, Loomis Lab Phys, Urbana, IL 61801 USA. Univ Illinois, Ctr Theoret Astrophys, Dept Astron, Loomis Lab Phys, Urbana, IL 61801 USA. Univ Arizona, Dept Astron, Tucson, AZ 85721 USA. CSIC, Inst Estructura Mat, E-28006 Madrid, Spain. Liverpool John Moores Univ, ARI, Wirral CH41 1LD, Cheshire, England. NASA, Goddard Space Flight Ctr, Raytheon Informat Technol Serv, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Raytheon Sci Serv, Greenbelt, MD 20771 USA. Cardiff Univ, Dept Phys & Astron, Cardiff CF24 3YB, S Glam, Wales. Space Telescope Sci Inst, ESA Space Telescope Div, Baltimore, MD 21218 USA. RP McDowell, JC (reprint author), Harvard Smithsonian Ctr Astrophys, 60 Garden St, Cambridge, MA 02138 USA. NR 45 TC 53 Z9 53 U1 0 U2 1 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 JUL 1 PY 2003 VL 591 IS 1 BP 154 EP 166 DI 10.1086/375289 PN 1 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 691QR UT WOS:000183617400011 ER PT J AU Juvela, M Padoan, P Jimenez, R AF Juvela, M Padoan, P Jimenez, R TI Photoelectric heating and [C II] cooling in translucent clouds: Results for cloud models based on simulations of compressible magnetohydrodynamic turbulence SO ASTROPHYSICAL JOURNAL LA English DT Article ID INTERSTELLAR-MEDIUM; SUPERSONIC TURBULENCE; RADIATIVE-TRANSFER; MOLECULAR CLOUDS; DARK CLOUDS; COLD DUST; EMISSION; EXTINCTION; GAS; COMPLEX AB Far-ultraviolet (FUV) photons expel electrons from interstellar dust grains and the excess kinetic energy of the electrons is converted into gas thermal energy through collisions. This photoelectric heating is believed to be the main heating mechanism in cool H I clouds. The heating rate cannot be directly measured, but it can be estimated through observations of the [C II] line emission, since this is believed to be the main coolant in regions where the photoelectric effect dominates the heating. Furthermore, the comparison of the [C II] emission with the far-infrared (FIR) emission allows us to constrain the efficiency of the photoelectric heating using model calculations that take into account the strength of the radiation field. Recent [C II] observations carried out with the Infrared Space Observatory satellite have made this study possible. In this work, we study the correlation between FUV absorption and FIR emission using three-dimensional models of the density distribution in H I clouds. The density distributions are obtained as the result of numerical simulations of compressible magnetohydrodynamic turbulence, with rms sonic Mach numbers of the flow ranging from subsonic to highly supersonic, 0.6 less than or equal to M-S less than or equal to 10. The FIR intensities are solved with detailed radiative transfer calculations. The [C II] line radiation is estimated assuming local thermodynamic equilibrium where the [C II] line cooling equals the FUV absorption multiplied by the unknown efficiency of the photoelectric heating, epsilon. The average ratio between the predicted [C II] and FIR emissions is found to be remarkably constant between different models, implying that the derived values of epsilon should not depend on the rms Mach number of the turbulence. The comparison of the models with the empirical data from translucent, high-latitude clouds yields an estimate of the photoelectric heating efficiency of epsilon similar to 2.9 x 10(-2) on the basis of the dust model of Li & Draine. This value confirms previous theoretical predictions. The observed correlation between [C II] and FIR emission contains a large scatter, even within individual clouds. Our models show that most of the scatter can be understood as resulting from the highly fragmented density field in turbulent H I clouds. The scatter can be reproduced with density distributions from supersonic turbulence, while subsonic turbulence fails to generate the observed scatter. C1 Univ Helsinki, Univ Helsinki Observ, SF-00014 Helsinki, Finland. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Penn, Dept Phys & Astron, Philadelphia, PA 19104 USA. RP Juvela, M (reprint author), Univ Helsinki, Univ Helsinki Observ, POB 14, SF-00014 Helsinki, Finland. RI Juvela, Mika/H-6131-2011; OI Juvela, Mika/0000-0002-5809-4834; Padoan, Paolo/0000-0002-5055-5800; Jimenez, Raul/0000-0002-3370-3103 NR 32 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 JUL 1 PY 2003 VL 591 IS 1 BP 258 EP 266 DI 10.1086/375344 PN 1 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 691QR UT WOS:000183617400017 ER PT J AU Hirotani, K Harding, AK Shibata, S AF Hirotani, K Harding, AK Shibata, S TI Electrodynamics of an outer gap accelerator: Formation of a soft power-law spectrum between 100 MeV and 3 GeV SO ASTROPHYSICAL JOURNAL LA English DT Article DE gamma rays : observations; gamma rays : theory; magnetic fields; methods : numerical; pulsars : individual (Geminga, PSR B1055-52, PSR B1706-44, Vela pulsar) ID GAMMA-RAY PULSARS; RAPIDLY SPINNING PULSARS; ELECTRIC-FIELD STRUCTURE; RADIATION PAIR FRONTS; X-RAY; CURVATURE-RADIATION; VELA PULSAR; POLAR CAPS; ENERGETIC RADIATION; EGRET OBSERVATIONS AB We investigate a stationary pair production cascade in the outer magnetosphere of a spinning neutron star. The charge depletion due to global flows of charged particles causes a large electric field along the magnetic field lines. Migratory electrons and/or positrons are accelerated by this field to radiate gamma-rays via curvature and inverse Compton processes. Some of these gamma-rays collide with the X-rays to materialize as pairs in the gap. The replenished charges partially screen the electric field, which is self-consistently solved together with the energy distribution of particles and gamma-rays at each point along the field lines. By solving the set of Maxwell and Boltzmann equations, we demonstrate that an external injection of charged particles at nearly Goldreich-Julian rate does not quench the gap but shifts its position and that the particle energy distribution cannot be described by a power law. The injected particles are accelerated in the gap and escape from it with large Lorentz factors. We show that such escaping particles migrating outside of the gap contribute significantly to the gamma-ray luminosity for young pulsars and that the soft gamma-ray spectrum between 100 MeV and 3 GeV observed for the Vela pulsar can be explained by this component. We also discuss that the luminosity of the gamma-rays emitted by the escaping particles is naturally proportional to the square root of the spin-down luminosity. C1 NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. Yamagata Univ, Dept Phys, Yamagata 9908560, Japan. RP Hirotani, K (reprint author), NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Code 661-0, Greenbelt, MD 20771 USA. RI Harding, Alice/D-3160-2012 NR 55 TC 56 Z9 59 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 JUL 1 PY 2003 VL 591 IS 1 BP 334 EP 353 DI 10.1086/375214 PN 1 PG 20 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 691QR UT WOS:000183617400024 ER PT J AU Titarchuk, L AF Titarchuk, L TI Rayleigh-Taylor gravity waves and quasi-periodic oscillation phenomena in X-ray binaries SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; MHD; stars : neutron; stars : oscillations; X-rays : binaries ID NEUTRON-STAR BINARIES; BLACK-HOLE BINARIES; SCORPIUS X-1; GRO J1655-40; WHITE-DWARF; FREQUENCY; DISCOVERY; FEATURES; VARIABILITY; 4U-1728-34 AB Accretion onto compact objects in X-ray binaries (black hole, neutron star [NS], white dwarf) is characterized by nonuniform flow density profiles. Such an effect of heterogeneity in the presence of gravitational forces and pressure gradients causes Rayleigh-Taylor gravity waves. They should be seen as quasi-periodic wave oscillations (QPOs) of the accretion flow in the transition (boundary) layer between the Keplerian disk and the central object. In this paper I show that the main QPO frequency, which is very close to the Keplerian frequency, is split into separate frequencies (hybrid and low branch) under the influence of the gravitational forces in the rotational frame of reference. The observed low and high QPO frequencies are an intrinsic signature of Rossby gravity waves (large-scale fluid motion in the rotational frame of reference). I elaborate the conditions for the density pro. le for which the gravity-wave oscillations are stable. A comparison of the inferred QPO frequencies with QPO observations is presented. I find that hectohertz frequencies detected from NS binaries can be identified as the low-branch frequencies of the gravity-wave oscillations. I also predict that an observer can see the double NS spin frequency (some sort of the Rossby wave phenomenon) during the NS long (super) burst events when the pressure gradients and buoyant forces are suppressed. The Coriolis force is the only force that acts in the rotational frame of reference, and its presence causes perfect coherent pulsations with a frequency twice that of the NS spin. The QPO observations of NS binaries have established that the high QPO frequencies do not go beyond a certain upper limit. I explain this observational effect as a result of the density pro. le inversions. In particular, I demonstrate that a particular problem of the gravity waves in the rotational frame of reference in the approximation of very small pressure gradients is reduced to the problem of the classical oscillator in the rotational frame of reference that was previously introduced and applied for the interpretation of the kHz QPO observations in our previous publications. The Rossby type of Rayleigh-Taylor gravity waves must be present, and the related QPOs should be detected in any system where the gravity, buoyancy, and Coriolis force effects cannot be excluded (even in the Earth and solar environments). C1 George Mason Univ, Naval Res Lab, Ctr Earth Observing & Space Res, Fairfax, VA 22030 USA. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Titarchuk, L (reprint author), George Mason Univ, Naval Res Lab, Ctr Earth Observing & Space Res, Fairfax, VA 22030 USA. NR 32 TC 21 Z9 22 U1 0 U2 1 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 JUL 1 PY 2003 VL 591 IS 1 BP 354 EP 360 DI 10.1086/367630 PN 1 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 691QR UT WOS:000183617400025 ER PT J AU Ng, CK Reames, DV Tylka, AJ AF Ng, CK Reames, DV Tylka, AJ TI Modeling shock-accelerated solar energetic particles coupled to interplanetary Alfven waves SO ASTROPHYSICAL JOURNAL LA English DT Article DE acceleration of particles; interplanetary medium; solar wind; Sun : particle emission; waves ID EARTHS BOW SHOCK; WEAKLY TURBULENT PLASMAS; COSMIC-RAY PROPAGATION; EJECTION-DRIVEN SHOCKS; IONIC CHARGE STATES; QUASI-LINEAR THEORY; TRAVELING SHOCKS; MAGNETIC-FIELD; ANGULAR-DISTRIBUTIONS; TEMPORAL EVOLUTION AB We present an idealized model simulating the coupled evolution of the distributions of multispecies shock-accelerated energetic ions and interplanetary Alfven waves in gradual solar energetic particle (SEP) events. Particle pitch-angle diffusion coefficients are expressed in terms of wave intensities, and wave growth rates in terms of momentum gradients of SEP distributions, by the same quasilinear theory augmented with resonance broadening. The model takes into consideration various physical processes: for SEPs, particle motion, magnetic focusing, scattering by Alfven waves, solar wind convection, and adiabatic deceleration; for the waves, WKB transport and amplification by streaming SEPs. Shock acceleration is heuristically represented by continuous injection of prescribed spectra of SEPs at a moving shock front. We show the model predictions for two contrasting sets of SEP source spectra, fast weakening and softening in one case and long lasting and hard in the other. The results presented include concurrent time histories of multispecies SEP intensities and elemental abundance ratios, as well as sequential snapshots of the following: SEP intensity energy spectra, Alfven wave spectra, particle mean free paths as functions of rigidity, and spatial profiles of SEP intensities and mean free paths. Wave growth plays a key role in both cases, although the magnitude of the wave growth differs greatly, and quite different SEP abundance variations are obtained. In these simulations, the maximum wave growth rate is large, but small relative to the wave frequency, and everywhere the total wave magnetic energy density remains small relative to that of the background magnetic field. The simulations show that, as the energetic protons stream outward, they rapidly amplify the ambient Alfven waves, by several orders of magnitude in the inner heliosphere. Energetic minor ions find themselves traveling through resonant Alfven waves previously amplified by higher velocity protons. The nonuniformly growing wave spectra alter the rigidity dependence of particle scattering, resulting in complex time variations of SEP abundances at large distances from the Sun. The greatly amplified waves travel outward in an expanding and weakening "shell," creating an expanding and falling "reservoir" of SEPs with. at spatial intensity profiles behind, while in and beyond the shell the intensities drop steeply. The wave-particle resonance relation dynamically links the evolving characteristics of the SEP and Alfven wave distributions in this new mode of SEP transport. We conclude that wave amplification, the counterpart to the scattering of streaming particles required by energy conservation, plays an essential role in the transport of SEPs in gradual SEP events. The steep proton-amplified wave spectra just upstream of the shock suggest that they may also be important in determining the elemental abundances of shock-accelerated SEP sources. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. USN, EO Hulburt Ctr Space Res, Res Lab, Washington, DC 20375 USA. Univ Maryland, Dept Astron, College Pk, MD 20742 USA. RP Ng, CK (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RI Tylka, Allan/G-9592-2014 NR 91 TC 105 Z9 106 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 JUL 1 PY 2003 VL 591 IS 1 BP 461 EP 485 DI 10.1086/375293 PN 1 PG 25 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 691QR UT WOS:000183617400036 ER PT J AU Opher, M Liewer, PC Gombosi, TI Manchester, W DeZeeuw, DL Sokolov, I Toth, G AF Opher, M Liewer, PC Gombosi, TI Manchester, W DeZeeuw, DL Sokolov, I Toth, G TI Probing the edge of the solar system: Formation of an unstable jet-sheet SO ASTROPHYSICAL JOURNAL LA English DT Article DE instabilities; interplanetary medium; ISM : kinematics and dynamics; MHD; solar wind; Sun : magnetic fields ID LOCAL INTERSTELLAR-MEDIUM; HELIOSPHERIC TERMINAL SHOCK; MAGNETIC-FIELD; FLOW DOWNSTREAM; ALPHA CENTAURI; GUITAR NEBULA; BOW SHOCKS; WIND; HELIOPAUSE; MAGNETOHYDRODYNAMICS AB The Voyager spacecraft is now approaching the edge of the solar system. Near the boundary between the solar system and the interstellar medium we find that an unstable "jet-sheet" forms. The jet-sheet oscillates up and down because of a velocity shear instability. This result is due to a novel application of a state-of-the-art three-dimensional MHD code with a highly refined grid. We assume as a first approximation that the solar magnetic and rotation axes are aligned. The effect of a tilt of the magnetic axis with respect to the rotation axis remains to be seen. We include in the model self-consistently magnetic field effects in the interaction between the solar and interstellar winds. Previous studies of this interaction had poorer spatial resolution and did not include the solar magnetic field. This instability can affect the entry of energetic particles into the solar system and the intermixing of solar and interstellar material. The same effect found here is predicted for the interaction of rotating magnetized stars possessing supersonic winds and moving with respect to the interstellar medium, such as O stars. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Michigan, Dept Atmospher Ocean & Space Sci, Space Phys Res Lab, Ann Arbor, MI 48109 USA. Eotvos Lorand Univ, Dept Atom Phys, Budapest, Hungary. RP Opher, M (reprint author), CALTECH, Jet Prop Lab, MS 169-506,4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM merav.opher@jpl.nasa.gov RI De Zeeuw, Darren/F-3667-2011; Manchester, Ward/I-9422-2012; Gombosi, Tamas/G-4238-2011; Toth, Gabor/B-7977-2013; Sokolov, Igor/H-9860-2013 OI Gombosi, Tamas/0000-0001-9360-4951; Toth, Gabor/0000-0002-5654-9823; Sokolov, Igor/0000-0002-6118-0469 NR 27 TC 36 Z9 36 U1 0 U2 4 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 JUL 1 PY 2003 VL 591 IS 1 BP L61 EP L65 DI 10.1086/376960 PN 2 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 691QZ UT WOS:000183618100016 ER PT J AU Sekanina, Z Chodas, PW Tichy, M Ticha, J Kocer, M AF Sekanina, Z Chodas, PW Tichy, M Ticha, J Kocer, M TI Peculiar pair of distant periodic comets C/2002 A1 and C/2002 A2 (LINEAR) SO ASTROPHYSICAL JOURNAL LA English DT Article DE comets : general; comets : individual (C/2002 A1, C/2002 A2); methods : data analysis ID SPLIT COMETS AB Distant comets C/2002 A1 and C/2002 A2 make up a peculiar pair that moves about the Sun in virtually identical, somewhat unstable orbits, extending currently between about 4.7 and 29 AU from the Sun. The two objects, observed since late 2001, are unquestionably of common origin. Analysis of their relative motion indicates that their parent body split nontidally most probably between mid-1977 and early 1979 at a heliocentric distance of 22.5 +/- 0.1 AU and about 2.5 AU below the ecliptic, with a separation velocity of 2.7 +/- 0.2 m s(-1). The motion of C/2002 A2, the secondary component that trails behind the primary, is found to be affected by a nongravitational deceleration of (13.4 +/- 1.5) x 10(-5) units of solar gravitational acceleration relative to C/2002 A1, which is in a range of decelerations that companions of split comets are usually subjected to. C/2002 A2 was somewhat less condensed and, interestingly, brighter than C/2002 A1. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Klet Observ, CZ-37001 Ceske Budejovice, Czech Republic. RP Sekanina, Z (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 34 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 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUL 1 PY 2003 VL 591 IS 1 BP L67 EP L70 DI 10.1086/376977 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 691QZ UT WOS:000183618100017 ER PT J AU de Paz, AG Madore, BF Pevunova, O AF de Paz, AG Madore, BF Pevunova, O TI Palomar/Las Campanas Imaging Atlas of blue compact dwarf galaxies. I. Images and integrated photometry SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Review ID EMISSION-LINE GALAXIES; STAR-FORMATION HISTORY; INFRARED STELLAR CENSUS; HUBBLE-SPACE-TELESCOPE; HEAVY-ELEMENT ABUNDANCES; LOW-LUMINOSITY GALAXIES; R-SURFACE PHOTOMETRY; WOLF-RAYET GALAXIES; DE-MADRID LIST; LOW-METALLICITY AB We present B, R, and Halpha images for a total of 114 nearby galaxies (v(helio) < 4000 km s(-1)) that, with exception of nine objects, are classified as blue compact dwarfs (BCDs). BR integrated magnitudes, H alpha fluxes and H alpha equivalent widths for all the objects in the sample are presented. A new set of quantitative, observational criteria for a galaxy to be classified as a BCD is proposed. These criteria include a limit on the K-band luminosity (i.e., stellar mass; M-K > -21 mag), peak surface brightness (mu(B;peak) < 22 mag arcsec(-2)), and color at the peak surface brightness (mu(B;peak) - mu(R;peak) less than or similar to 1). H alpha emission is detected in all but three sample galaxies. Typical color, absolute magnitude, and H alpha luminosity are (B - R) = 0.7 +/- 0.3 mag, M-B = -16.1 +/- 1.4 mag, and log (L-H alpha) = 40.0 +/- 0.6 (ergs s(-1)). Galaxies morphologically classified as nE and iE BCDs within our sample show lower H alpha equivalent widths and redder colors, on average, than the iI- and i0-type BCDs. For most of the galaxies the presence of an evolved stellar population is required to explain their observed properties; only the most metal-poor BCDs (e.g., I Zw 18, Tol 65) are still compatible with a pure, young burst. The flux-calibrated and WCS-compliant images in this Atlas are individually available through the NASA/IPAC Extragalactic Database (NED) image server and collectively through a dedicated Web page. C1 CALTECH, NASA, IPAC Extragalact Database, Pasadena, CA 91125 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Carnegie Inst Washington Observ, Pasadena, CA 91101 USA. RP CALTECH, NASA, IPAC Extragalact Database, MS 100-22, Pasadena, CA 91125 USA. EM agpaz@ipac.caltech.edu; barry@ipac.caltech.edu; olga@ipac.caltech.edu RI Gil de Paz, Armando/J-2874-2016 OI Gil de Paz, Armando/0000-0001-6150-2854 NR 109 TC 195 Z9 195 U1 0 U2 3 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0067-0049 EI 1538-4365 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD JUL PY 2003 VL 147 IS 1 BP 29 EP 59 DI 10.1086/374737 PG 31 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 693DT UT WOS:000183700700002 ER PT J AU Lanz, T Hubeny, I AF Lanz, T Hubeny, I TI A grid of non-LTE line-blanketed model atmospheres of O-type stars (vol 146, pg 417, 2003) SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Correction AB We have constructed a comprehensive grid of 680 metal line-blanketed, non-LTE, plane-parallel, hydrostatic model atmospheres for the basic parameters appropriate to O-type stars. The OSTAR2002 grid considers 12 values of effective temperatures, 27,500K less than or equal to T-eff less than or equal to 55,000 K with 2500 K steps, eight surface gravities, 3.0 less than or equal to log g less than or equal to 4.75 with 0.25 dex steps, and 10 chemical compositions, from metal-rich relative to the Sun to metal-free. The lower limit of for a given effective temperature is set by an approximate location of the Eddington limit. The selected chemical compositions have been chosen to cover a number of typical environments of massive stars: the Galactic center, the Magellanic Clouds, blue compact dwarf galaxies like I Zw 18, and galaxies at high redshifts. The paper contains a description of the OSTAR2002 grid and some illustrative examples and comparisons. The complete OSTAR2002 grid is available at our Web site at http://tlusty.gsfc.nasa.gov. C1 Univ Maryland, Dept Astron, College Pk, MD 20742 USA. Natl Opt Astron Observ, Tucson, AZ 85726 USA. NASA, Astron & Solar Phys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Lanz, T (reprint author), Univ Maryland, Dept Astron, College Pk, MD 20742 USA. NR 1 TC 5 Z9 6 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 JUL PY 2003 VL 147 IS 1 BP 225 EP 225 DI 10.1086/377130 PG 1 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 693DT UT WOS:000183700700013 ER PT J AU Harris, JM Oltmans, ST Bodeker, GE Stolarski, R Evans, RD Quincy, DM AF Harris, JM Oltmans, ST Bodeker, GE Stolarski, R Evans, RD Quincy, DM TI Long-term variations in total ozone derived from Dobson and satellite data SO ATMOSPHERIC ENVIRONMENT LA English DT Article DE trend; growth rate; quasi-decadal variations; recovery; dynamical trend ID STRATOSPHERIC OZONE; NORTHERN MIDLATITUDES; TRENDS; LOSSES AB Total ozone growth rates are calculated using flexible 'tendency curves' that can follow ozone variations on all timescales greater than that of the quasi-biennial oscillation. This method improves on traditional trend analysis using straight line fits because it follows ozone variations more closely, providing visual information about the timing and global distribution of ozone variations. Results are compared from long-running Dobson sites and from two homogenized satellite data sets, one constructed at NASA/Goddard Space Flight Center and the other developed at New Zealand's National Institute of Water and Atmospheric Research. Although the most negative ozone trends in the Southern Hemisphere appear to be linked to polar vortex chemistry, those in the Northern Hemisphere have occurred between 35degreesN and 40degreesN and may be related to dynamical trends and/or chemistry on episodically occurring volcanic aerosols. A quasi-decadal cycle in total ozone was present since the mid-1920s and hence is independent of halogen chemistry. Its cause remains unknown. Including the deseasonalized and detrended local temperature in the ozone trend model decreases the standard error of the ozone trend over most of the globe. (C) 2003 Elsevier Science Ltd. All rights reserved. C1 NOAA Climate Monitoring & Diagnost Lab, Boulder, CO 80305 USA. Natl Inst Water & Atmospher Res, Lauder, New Zealand. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. RP Harris, JM (reprint author), NOAA Climate Monitoring & Diagnost Lab, 325 Broadway, Boulder, CO 80305 USA. RI Stolarski, Richard/B-8499-2013; Evans, Robert/D-4731-2016; OI Stolarski, Richard/0000-0001-8722-4012; Evans, Robert/0000-0002-8693-9769; Bodeker, Gregory/0000-0003-1094-5852 NR 23 TC 13 Z9 13 U1 0 U2 0 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 JUL PY 2003 VL 37 IS 23 BP 3167 EP 3175 DI 10.1016/S1352-2310(03)00347-9 PG 9 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA 701UZ UT WOS:000184188500001 ER PT J AU Schlegel, TT Wood, SJ Brown, TE Harm, DL Rupert, AH AF Schlegel, TT Wood, SJ Brown, TE Harm, DL Rupert, AH TI Effect of 30-min+3 Gz centrifugation on vestibular and autonomic cardiovascular function SO AVIATION SPACE AND ENVIRONMENTAL MEDICINE LA English DT Article DE orthostatic tolerance; otolith; baroreflex; Valsalva maneuver; motion sickness ID CARDIAC REFLEX RESPONSES; PARABOLIC FLIGHT; ORTHOSTATIC INTOLERANCE; BAROREFLEX ADAPTATION; MOTION SICKNESS; POWER SPECTRA; TILT; MECHANISMS; EXPOSURE; SYNCOPE AB Introduction: Repeated exposure to increased +Gz enhances human baroreflex responsiveness and improves tolerance to cardiovascular stress. However, it is not known whether such enhancements might also result from a single, more prolonged exposure to increased +Gz. Our study was designed to investigate whether baroreflex function and orthostatic tolerance are acutely improved by a single prolonged exposure to +3 Gz, and moreover, whether changes in autonomic cardiovascular function resulting from exposure to increased +Gz are correlated with changes in otolith function. Methods: We exposed 15 healthy human subjects to +3 Gz centrifugation for up to 30 min or until symptoms of incipient G-induced loss of consciousness (G-LOC) ensued. Tests of autonomic cardiovascular function both before and after centrifugation included: 1) power spectral determinations of beat-to-beat R-R intervals and arterial pressures; 2) carotid-cardiac baroreflex tests; 3) Valsalva tests; and 4) 30-min head-up tilt tests. Otolith function was assessed during centrifugation by the linear vestibulo-ocular reflex and both before and after centrifugation by measurements of ocular counterrolling and dynamic posturography. Results: Of the 15 subjects who underwent prolonged +3 G, 4 were intolerant to 30 min of head-up tilt before centrifugation but became tolerant to such tilt after centrifugation. The Valsalva-related baroreflex as well as a measure of the carotidcardiac baroreflex were also enhanced after centrifugation. No significant vestibular-autonomic relationships were detected beyond a vestibular-cerebrovascular interaction reported earlier in a subset of seven participants. Conclusions: A single prolonged exposure to +3 G centrifugation acutely improves baroreflex function and orthostatic tolerance. C1 NASA, Lyndon B Johnson Space Ctr, Human Adaptat & Countermeasures Off, Houston, TX 77058 USA. USN, Aerosp Med Res Lab, Naval Air Stn, Pensacola, FL USA. Wyle Labs, Houston, TX USA. RP Schlegel, TT (reprint author), NASA, Lyndon B Johnson Space Ctr, Human Adaptat & Countermeasures Off, Mail Code SK3, Houston, TX 77058 USA. NR 29 TC 4 Z9 5 U1 0 U2 0 PU AEROSPACE MEDICAL ASSOC PI ALEXANDRIA PA 320 S HENRY ST, ALEXANDRIA, VA 22314-3579 USA SN 0095-6562 J9 AVIAT SPACE ENVIR MD JI Aviat. Space Environ. Med. PD JUL PY 2003 VL 74 IS 7 BP 717 EP 724 PG 8 WC Public, Environmental & Occupational Health; Medicine, General & Internal; Sport Sciences SC Public, Environmental & Occupational Health; General & Internal Medicine; Sport Sciences GA 696RR UT WOS:000183901500004 PM 12862325 ER PT J AU Perez, SA Charles, JB Fortner, GW Hurst, V Meck, JV AF Perez, SA Charles, JB Fortner, GW Hurst, V Meck, JV TI Cardiovascular effects of anti-G suit and cooling garment during space shuttle re-entry and landing SO AVIATION SPACE AND ENVIRONMENTAL MEDICINE LA English DT Article DE arterial pressure; heart rate; heat stress; spaceflight; launch/entry suit; ACES ID ORTHOSTATIC INTOLERANCE; MILD HYPOVOLEMIA; SPACEFLIGHT; HUMANS; FLIGHT; EFFICACY AB Background: Many cardiovascular changes associated with spaceflight reduce the ability of the cardiovascular system to oppose gravity on return to Earth, leaving astronauts susceptible to orthostatic hypotension during re-entry and landing. Consequently, an anti-G suit was developed to protect arterial pressure during re-entry. A liquid cooling garment (LCG) was then needed to alleviate the thermal stress resulting from use of the launch and entry suit. Methods: We studied 34 astronauts on 22 flights (4-16 d). Subjects were studied 10 d before launch and on landing day. Preflight, crewmembers were suited with their anti-G suits set to the intended inflation for re-entry. Three consecutive measurements of heart rate and arterial pressure were obtained while seated and then again while standing. Three subjects who inflated the anti-G suits also donned the LCG for landing. Arterial pressure and heart rate were measured every 5 min during the de-orbit maneuver, through maximum G-loading (max-G) and touch down (TD). After TD, crewmembers again initiated three seated measurements followed by three standing measurements. Results: Astronauts with inflated anti-G suits had higher arterial pressure than those who did not have inflated anti-G suits during re-entry and landing (133.1 +/- 2.5/76.1 +/- 2.1 vs. 128.3 +/- 4.2/79.3 +/- 2.9, de-orbit; 157.3 +/- 4.5/102.1 +/- 3.6 vs. 145.2 +/- 10.5/ 95.7 +/- 5.5, max-G; 159.6 +/- 3.9/103.7 +/- 3.3 vs. 134.1 +/- 5.1/85.7 +/- 3.1, TD). In the group with inflated anti-G suits, those who also wore the LCG exhibited significantly lower heart rates than those who did not (75.7 +/- 11.5 vs. 86.5 +/- 6.2, de-orbit; 79.5 +/- 24.8 vs. 112.1 +/- 8.7, max-G; 84.7 +/- 8.0 vs. 110.5 +/- 7.9, TD). Conclusions: The anti-G suit is effective in supporting arterial pressure. The addition of the LCG lowers heart rate during re-entry. C1 NASA, Lyndon B Johnson Space Ctr, Space Life Sci Res Labs, SK, Houston, TX 77058 USA. Wyle Labs, Houston, TX USA. RP Meck, JV (reprint author), NASA, Lyndon B Johnson Space Ctr, Space Life Sci Res Labs, SK, Houston, TX 77058 USA. NR 22 TC 12 Z9 12 U1 1 U2 5 PU AEROSPACE MEDICAL ASSOC PI ALEXANDRIA PA 320 S HENRY ST, ALEXANDRIA, VA 22314-3579 USA SN 0095-6562 J9 AVIAT SPACE ENVIR MD JI Aviat. Space Environ. Med. PD JUL PY 2003 VL 74 IS 7 BP 753 EP 757 PG 5 WC Public, Environmental & Occupational Health; Medicine, General & Internal; Sport Sciences SC Public, Environmental & Occupational Health; General & Internal Medicine; Sport Sciences GA 696RR UT WOS:000183901500009 PM 12862330 ER PT J AU Fitzpatrick, DT Conkin, J AF Fitzpatrick, DT Conkin, J TI Improved pulmonary function in working divers breathing nitrox at shallow depths SO AVIATION SPACE AND ENVIRONMENTAL MEDICINE LA English DT Article DE diving; lung function; forced vital capacity; hyperoxia ID LUNG-FUNCTION; OXYGEN AB Introduction: There is limited data about the long-term pulmonary effects of nitrox use in divers at shallow depths. This study examined changes in pulmonary function in a cohort of working divers breathing a 46% oxygen enriched mixture while diving at depths less than 12 m. Methods: A total of 43 working divers from the Neutral Buoyancy Laboratory (NBL), NASA-Johnson Space Center completed a questionnaire providing information on diving history prior to NBL employment, diving history outside the NBL since employment, and smoking history. Cumulative dive hours were obtained from the NBL dive-time database. Medical records were reviewed to obtain the diver's height, weight, and pulmonary function measurements from initial pre-dive, first year and third year annual medical examinations. Results: The initial forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV1) were greater than predicted, 104% and 102%, respectively. After 3 yr of diving at the NBL, both the FVC and FEV1 showed a significant (p < 0.01) increase of 6.3% and 5.5%, respectively. There were no significant changes in peak expiratory flow (PEF), forced mid-expiratory flow rate (FEF25-75%), and forced expiratory flow rates at 25%, 50%, and 75% of FVC expired (FEF25%, FEF50%, FEF75%). Cumulative NBL dive hours was the only contributing variable found to be significantly associated with both FVC and FEV1 at 1 and 3 yr. Conclusions: NBL divers initially belong to a select group with larger than predicted lung volumes. Regular diving with nitrox at shallow depths over a 3-yr period did not impair pulmonary function. Improvements in FVC and FEV1 were primarily due to a training effect. C1 NASA, Lyndon B Johnson Space Ctr, Sonny Carter Training Facil, Neutral Buoyancy Lab, Houston, TX 77058 USA. RP Fitzpatrick, DT (reprint author), NASA, Lyndon B Johnson Space Ctr, Sonny Carter Training Facil, Neutral Buoyancy Lab, SD37,2101 NASA Rd 1, Houston, TX 77058 USA. NR 18 TC 5 Z9 5 U1 1 U2 1 PU AEROSPACE MEDICAL ASSOC PI ALEXANDRIA PA 320 S HENRY ST, ALEXANDRIA, VA 22314-3579 USA SN 0095-6562 J9 AVIAT SPACE ENVIR MD JI Aviat. Space Environ. Med. PD JUL PY 2003 VL 74 IS 7 BP 763 EP 767 PG 5 WC Public, Environmental & Occupational Health; Medicine, General & Internal; Sport Sciences SC Public, Environmental & Occupational Health; General & Internal Medicine; Sport Sciences GA 696RR UT WOS:000183901500011 PM 12862332 ER PT J AU Wal, RLV Tomasek, AJ AF Wal, RLV Tomasek, AJ TI Soot oxidation: dependence upon initial nanostructure SO COMBUSTION AND FLAME LA English DT Article DE soot oxidation; nanostructure ID LAMINAR DIFFUSION FLAME; HIGH-TEMPERATURE; CARBON NANOTUBES; PARTICLES; EVOLUTION; CRYSTALLINITY; METHODOLOGY; COMBUSTION; GRAPHITE; BLACK AB Although the relation between carbon structure and reactivity is well-known from thermal and oxidative studies of coal, char, and graphite, the relation for soot remains unstudied. In this article, the dependence of the soot oxidation rate upon the length and curvature of the graphene segments, which depicts the nanostructure, is shown. Reflecting different ratios of edge to basal plane sites or amounts of ring strain imposed by curvature, burnout rates are found to differ by greater than 400% for the soots studied here. Surprisingly, the different soot nanostructures are readily produced by using different fuels and pyrolysis conditions. (C) 2003 The Combustion Institute. All rights reserved. C1 NASA Glenn, NCMR, Cleveland, OH 44135 USA. RP Wal, RLV (reprint author), NASA Glenn, NCMR, Cleveland, OH 44135 USA. NR 42 TC 7 Z9 7 U1 1 U2 23 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 JUL PY 2003 VL 134 IS 1-2 BP 1 EP 9 DI 10.1016/S0010-2180(03)00084-1 PG 9 WC Thermodynamics; Energy & Fuels; Engineering, Multidisciplinary; Engineering, Chemical; Engineering, Mechanical SC Thermodynamics; Energy & Fuels; Engineering GA 708BL UT WOS:000184546600001 ER PT J AU Baurle, RA Girimaji, SS AF Baurle, RA Girimaji, SS TI Assumed PDF turbulence-chemistry closure with temperature-composition correlations SO COMBUSTION AND FLAME LA English DT Article DE turbulence-chemistry closure; PDF; CFD; scramjet ID PROBABILITY DENSITY-FUNCTIONS; COMBUSTION AB An assumed probability density function (PDF) approach that accounts for temperature and composition fluctuations, including effects of temperature-composition correlations, has been developed. Parametric studies were performed to determine the gross behavior of the assumed PDF and provide insight into the expected trends of the model for a given kinetic mechanism. The model was implemented into an existing Navier-Stokes solver and applied to a supersonic, co-axial H-2/air burner. Proper prediction of the turbulence effects on the chain initiating step of the kinetic process is a first-order concern in supersonic combustion applications because of small flow residence times. Temperature-composition correlations were extracted and compared with results obtained by direct integration of a PDF evolution equation. The results of this comparison showed that the model properly predicted both the magnitude and sign of the cross-correlation terms associated with the chain initiating step of the H-2/air kinetic mechanism. Correlations for all but one of the remaining kinetic steps qualitatively reproduced those obtained by direct integration. (C) 2003 The Combustion Institute. All rights reserved. C1 NASA LaRC, ICASE, Hampton, VA 23681 USA. Taitech Inc, Beavercreek, OH 45430 USA. RP Baurle, RA (reprint author), NASA, Langley Res Ctr, Hampton, VA 23665 USA. NR 18 TC 35 Z9 37 U1 0 U2 3 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 JUL PY 2003 VL 134 IS 1-2 BP 131 EP 148 DI 10.1016/S0010-2180(03)00056-7 PG 18 WC Thermodynamics; Energy & Fuels; Engineering, Multidisciplinary; Engineering, Chemical; Engineering, Mechanical SC Thermodynamics; Energy & Fuels; Engineering GA 708BL UT WOS:000184546600011 ER PT J AU Fatt, MSH Lin, CF Revilock, DM Hopkins, DA AF Fatt, MSH Lin, CF Revilock, DM Hopkins, DA TI Ballistic impact of GLARE (TM) fiber-metal laminates SO COMPOSITE STRUCTURES LA English DT Article; Proceedings Paper CT 14th US National Congress of Theoretical and Applied Mechanics CY JUN 23-28, 2002 CL BLACKSBURG, VIRGINIA DE GLARE; aluminum-glass/epoxy laminate; global deformation; delamination; tensile fracture; energy partition ID COMPOSITES; STRAIN; RATES AB Analytical solutions to predict the ballistic limit and energy absorption of fully clamped GLARE panels subjected to ballistic impact by a blunt cylinder were derived. The analytical solutions were based on test results from NASA Glenn. The ballistic limit was found through an iterative process such that the initial kinetic energy of the projectile would equal the total energy dissipated by panel deformation, delamination/debonding and fracture. The transient deformation of the panel as shear waves propagate from the point of impact was obtained from an equivalent mass-spring system, whereby the inertia and stiffness depend on the shear wave speed and time. Predictions of the ballistic limit from the resulting non-linear differential equation were within 13% of the test data. The deformation energy due to bending and membrane accounted for most of the total energy absorbed (84-92%), with the thinner panels absorbing a higher percentage of deformation energy than the thicker panels. Energy dissipated in delamination represented 2-9% of the total absorbed energy, with the thinner panels absorbing a lower percentage of delamination energy than the thicker panels. About 7% of the total energy was attributed to tensile fracture energy of the glass/epoxy and aluminum. (C) 2003 Elsevier Science Ltd. All rights reserved. C1 Univ Akron, Dept Mech Engn, Akron, OH 44325 USA. NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Fatt, MSH (reprint author), Univ Akron, Dept Mech Engn, Akron, OH 44325 USA. NR 19 TC 74 Z9 74 U1 4 U2 12 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0263-8223 J9 COMPOS STRUCT JI Compos. Struct. PD JUL-AUG PY 2003 VL 61 IS 1-2 BP 73 EP 88 DI 10.1016/S0263-8223(03)00036-9 PG 16 WC Materials Science, Composites SC Materials Science GA 683KT UT WOS:000183147900008 ER PT J AU Montero, RS Llorente, IM Salas, MD AF Montero, RS Llorente, IM Salas, MD TI Semicoarsening smoothers for the simulation of a flat plate at yaw SO COMPUTERS & FLUIDS LA English DT Article DE plane implicit smoothers; semicoarsening; robust multigrid; flat plate; boundary layers ID NAVIER-STOKES EQUATIONS; MULTIGRID SOLUTION AB This paper presents a full multigrid solver for the simulation of flow over a yawed flat plate. The two problems associated with this simulation; boundary layers and entering flows with non-aligned characteristics, have been successfully overcome through the combination of a plane-implicit solver and semi-coarsening. In fact, this multigrid algorithm exhibits a textbook multigrid convergence rate, i.e., the solution of the discrete system of equations is obtained in a fixed amount of computational work, independently of the grid size, grid stretching factor and non-alignment parameter. Also, a parallel variant of the smoother based on a four-color ordering of planes is investigated. (C) 2002 Elsevier Science Ltd. All rights reserved. C1 Univ Complutense, Dept Arquitectura Computadores & Automat, Fac Ciencias Fs, E-28040 Madrid, Spain. NASA, ICASE, Langley Res Ctr, Hampton, VA 23681 USA. RP Montero, RS (reprint author), Univ Complutense, Dept Arquitectura Computadores & Automat, Fac Ciencias Fs, E-28040 Madrid, Spain. EM rubensm@dacya.ucm.es RI Martin Llorente, Ignacio/B-2093-2009; Montero, Ruben/C-5346-2008 OI Martin Llorente, Ignacio/0000-0001-6230-8180; Montero, Ruben/0000-0003-2591-1719 NR 25 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 0045-7930 J9 COMPUT FLUIDS JI Comput. Fluids PD JUL PY 2003 VL 32 IS 6 BP 873 EP 890 AR PII S0045-7930(02)00020-8 DI 10.1016/S0045-7930(02)00020-8 PG 18 WC Computer Science, Interdisciplinary Applications; Mechanics SC Computer Science; Mechanics GA 657UN UT WOS:000181684900005 ER PT J AU Muravyov, AA Rizzi, SA AF Muravyov, AA Rizzi, SA TI Determination of nonlinear stiffness with application to random vibration of geometrically nonlinear structures SO COMPUTERS & STRUCTURES LA English DT Article DE geometric nonlinearity; nonlinear stiffness; nonlinear dynamics; random vibration; equivalent linearization AB A novel method for determining the nonlinear modal stiffness coefficients for an arbitrary finite element model is presented. The method is applicable to a wide class of problems exhibiting bending-membrane coupling and is suitable for use with commercial finite element codes having a geometrically nonlinear static capability. The equations of motion are written in modal coordinates with the nonlinear stiffness force components written as the product of second and third order modal displacements multiplied by unknown coefficients. Prescription of particular displacement fields renders a series of inverse linear and nonlinear static problems, which are solved to determine the unknown coefficients. Verification of stiffness coefficients found using this method and their use in equivalent linearization random vibration analysis are presented. Published by Elsevier Science Ltd. C1 NASA, Langley Res Ctr, Struct Acoust Branch, Hampton, VA 23681 USA. RP Rizzi, SA (reprint author), NASA, Langley Res Ctr, Struct Acoust Branch, Mail Stop 463, Hampton, VA 23681 USA. NR 17 TC 49 Z9 51 U1 1 U2 8 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 JUL PY 2003 VL 81 IS 15 BP 1513 EP 1523 DI 10.1016/S0045-7949(03)00145-7 PG 11 WC Computer Science, Interdisciplinary Applications; Engineering, Civil SC Computer Science; Engineering GA 685XM UT WOS:000183289700001 ER PT J AU Keesecker, AL Davila, CG Johnson, ER Starnes, JH AF Keesecker, AL Davila, CG Johnson, ER Starnes, JH TI Crack path bifurcation at a tear strap in a pressurized shell SO COMPUTERS & STRUCTURES LA English DT Article DE cylindrical shell; tear strap; internal pressure; crack growth; experiment; nonlinear analysis AB Bifurcation of an initially longitudinal through crack in an internally pressurized cylindrical shell at a circumferential stiffener is investigated using a finite element analysis. The finite element model is developed from a fracture test of an aluminum shell having a 22.9 cm radius, a 1.02 mm wall thickness, and stiffened by two externally bonded circumferential straps spaced 40.6 cut apart. After initial stable crack growth in the longitudinal direction with increasing pressure, the crack propagated dynamically toward the strap, bifurcated near the strap into circumferential branches running parallel to the straps. Stable and unstable crack growth curves of pressure versus half-crack length are determined from the nonlinear analysis using a critical value of the crack tip opening angle as the criterion to predict crack growth. Although the crack growth curves are determined from a static analysis, they corroborate the test results for the location of crack path bifurcation. Also, the principal stress criterion for predicting crack turning is consistent with the test. (C) 2003 Published by Elsevier Science Ltd. C1 USN, Ctr Surface Warfare, Marine Composites Branch, Carderock Div, Bethesda, MD 20817 USA. NASA, Langley Res Ctr, Analyt & Computat Methods Branch, Hampton, VA 23681 USA. Virginia Polytech Inst & State Univ, Dept Aerosp & Ocean Engn, Blacksburg, VA 24061 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Keesecker, AL (reprint author), USN, Ctr Surface Warfare, Marine Composites Branch, Carderock Div, Code 6552,9500 MacArthur Blvd, Bethesda, MD 20817 USA. RI Davila, Carlos/D-8559-2011 NR 22 TC 13 Z9 13 U1 0 U2 1 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 JUL PY 2003 VL 81 IS 16 BP 1633 EP 1642 DI 10.1016/S0045-7949(03)00165-2 PG 10 WC Computer Science, Interdisciplinary Applications; Engineering, Civil SC Computer Science; Engineering GA 693PH UT WOS:000183725600004 ER PT J AU Vaillancourt, RD Marra, J Seki, MP Parsons, ML Bidigare, RR AF Vaillancourt, RD Marra, J Seki, MP Parsons, ML Bidigare, RR TI Impact of a cyclonic eddy on phytoplankton community structure and photosynthetic competency in the subtropical North Pacific Ocean SO DEEP-SEA RESEARCH PART I-OCEANOGRAPHIC RESEARCH PAPERS LA English DT Article DE mesoscale processes; cyclonic eddies; phytoplankton; biological-physical coupling; variable fluorescence; photosynthetic quantum yield; diazotrophic diatoms; subtropical North Pacific Ocean ID QUANTUM YIELD; SARGASSO SEA; OLIGOTROPHIC WATERS; NITROGEN LIMITATION; ENERGY-CONVERSION; ATLANTIC OCEAN; SURFACE WATERS; STATION ALOHA; VARIABILITY; FLUORESCENCE AB A synoptic spatial examination of the eddy Haulani (17-20 November 2000) revealed a structure typical of Hawaiian cyclonic eddies with divergent surface flow forcing the upward displacement of deep waters, Hydrographic surveys revealed that surface water in the eddy center was ca. 3.5degreesC cooler, 0.5 saltier, and 1.4 kg m(-3) denser than surface waters outside the eddy. Vertically integrated concentrations of nitrate+nitrite, phosphate and silicate were enhanced over out-eddy values by about 2-fold, and nitrate+nitrite concentrations were ca. 8 x greater within the euphotic zone inside the eddy than outside. Si:N ratios were lower within the upper mixed layer of the eddy, indicating an enhanced Si uptake relative to nitrate+nitrite. Chlorophyll a concentrations were higher within the eddy compared to control stations outside, when integrated over the upper 150 m, but were not significantly different when integrated over the depth of the euphotic zone. Photosynthetic competency, assessed using fast repetition-rate fluorometry, varied with the doming of the isopycnals and the supply of macro-nutrients to the euphotic zone. The physical and chemical environment of the eddy selected for the accumulation of larger phytoplankton species. Photosynthetic bacteria (Prochlorococcus and Synechococcus) and small (<3 μm diameter) photosynthetic eukaryotes were 3.6-fold more numerically abundant outside the eddy as compared to inside. Large photosynthetic eukaryotes (>3 mum diameter) were more abundant inside the eddy than outside. Diatoms of the genera Rhizosolenia and Hemiaulus outside the eddy contained diazotrophic endosymbiontic cyanobacteria, but these endosymbionts were absent from the cells of these species inside the eddy. The increase in cell numbers of large photosynthetic eukaryotes with hard silica or calcite cell walls is likely to have a profound impact on the proportion of the organic carbon production that is exported to deep water by sinking of senescent cells and cells grazed by herbivorous zooplankton and repackaged as large fecal pellets. (C) 2003 Elsevier Science Ltd. All rights reserved. C1 Columbia Univ, Lamont Doherty Earth Observ, Palisades, NY 10964 USA. NOAA, Natl Marine Fisheries Serv, SW Fisheries Sci Ctr, Honolulu, HI 96819 USA. Univ Hawaii, Dept Marine Sci, Hilo, HI 96720 USA. Univ Hawaii, Dept Oceanog, Honolulu, HI 96822 USA. RP Vaillancourt, RD (reprint author), Columbia Univ, Lamont Doherty Earth Observ, Marine Biol Room 2B,61 Route 9W, Palisades, NY 10964 USA. EM vaillanc@ldeo.columbia.edu NR 50 TC 89 Z9 93 U1 3 U2 11 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0967-0637 J9 DEEP-SEA RES PT I JI Deep-Sea Res. Part I-Oceanogr. Res. Pap. PD JUL PY 2003 VL 50 IS 7 BP 829 EP 847 DI 10.1016/S0967-0637(03)00059-1 PG 19 WC Oceanography SC Oceanography GA 767NZ UT WOS:000188458500001 ER PT J AU El-Genk, MS Saber, HH Caillat, T AF El-Genk, MS Saber, HH Caillat, T TI Efficient segmented thermoelectric unicouples for space power applications SO ENERGY CONVERSION AND MANAGEMENT LA English DT Article DE segmented thermoelectric; skutterudites; energy conversion; space exploration; radioisotope power systems; radioisotope thermoelectric generators (RTGs); space nuclear reactor power systems AB This paper compares the performance of SiGe (Si0.8Ge0.2) and skutterudite segmented thermoelectric unicouples (STUs) at a hot side temperature of 973 K and cold side temperatures of 300, 573 and 673 K and for the same total length and cross sectional dimensions of the p-leg. The area of the n-leg and lengths of and the interfacial temperatures between segments of various materials in the STU legs are determined using a global optimization methodology. Results indicate that the STUs could potentially achieve peak efficiencies of 7.8% and 14.7% when operated at a cold side temperature of 573 K, typical of that in current radioisotope thermoelectric generators (RTGs), and 300 K, respectively. These efficiencies are 55% and 99% higher, respectively, than for SiGe at the same temperatures. However, due to the higher density of skutterudite, the electrical power densities corresponding to the peak. efficiencies of the STUs are 39 and 109 W-e/kg versus 92 and 232 W-e/kg for SiGe at cold side temperatures of 573 K and 300 K, respectively. On the other hand, the heat inputs and heat rejection powers for the STUs are 42-55% and 39-53%, respectively, of those for SiGe at the peak efficiency and 70-75% and 67-77% of those of SiGe, respectively, at the peak electric power density. Therefore, when used in RTGs, STUs could halve the (PuO2)-Pu-238 fuel mass and the radiator area, while operating at >45% higher electrical power density (>7 W-e/kg) than SiGe in current RTGs (similar to5.5 W-e/kg). (C) 2002 Elsevier Science Ltd. All rights reserved. C1 Univ New Mexico, Inst Space & Nucl Power Studies, Dept Chem & Nucl Engn, Albuquerque, NM 87131 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP El-Genk, MS (reprint author), Univ New Mexico, Inst Space & Nucl Power Studies, Dept Chem & Nucl Engn, Albuquerque, NM 87131 USA. NR 15 TC 44 Z9 47 U1 5 U2 40 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 JUL PY 2003 VL 44 IS 11 BP 1755 EP 1772 AR PII S0196-8904(02)00217-0 DI 10.1016/S0196-8904(02)00217-0 PG 18 WC Thermodynamics; Energy & Fuels; Mechanics SC Thermodynamics; Energy & Fuels; Mechanics GA 649MV UT WOS:000181213300002 ER PT J AU Berejikian, BA Tezak, EP LaRae, AL AF Berejikian, BA Tezak, EP LaRae, AL TI Innate and enhanced predator recognition in hatchery-reared chinook salmon SO ENVIRONMENTAL BIOLOGY OF FISHES LA English DT Article DE Oncorhynchus tshawytscha; anti-predator conditioning; fright response ID TROUT ONCORHYNCHUS-MYKISS; FATHEAD MINNOWS; PIMEPHALES-PROMELAS; NORTHERN PIKE; ESOX-LUCIUS; ACQUIRED RECOGNITION; JUVENILE CHINOOK; CHEMICAL STIMULI; ATLANTIC SALMON; COHO SALMON AB We used a laboratory behaviour assay to investigate how innate predator recognition, handling stress, retention time, and number of conditioning events might affect chemically mediated anti-predator conditioning for hatchery-reared chinook salmon, Oncorhynchus tshawytscha. Juvenile chinook salmon with no prior exposure to predatory stimuli exhibited innate fright responses to northern pikeminnow, Ptychocheilis oregonensis, odour, regardless of whether the salmon came from a population that exists in sympatry or allopatry with northern pikeminnows. Juvenile chinook salmon exhibited enhanced predator recognition following a single conditioning event with conspecific extract and northern pikeminnow odour. Handling similar to what hatchery salmon might experience prior to release did not substantially reduce the conditioned response. When we conditioned juvenile chinook salmon in hatchery rearing vessels, fish from tanks treated once exhibited a conditioned response to northern pikeminnow odour in aquaria, but only for one behaviour ( feeding response), and fish treated twice did not respond. The results suggest that enhanced recognition of predator stimuli occurs quickly, but may be to some extent context-specific, which may limit conditioned fright responses after release into the natural environment. C1 Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, Resource Enhancement & Utilizat Technol Div, Manchester Res Stn, Manchester, WA 98353 USA. Pacific States Marine Fisheries Commiss, Gladstone, OR 97027 USA. RP Berejikian, BA (reprint author), Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, Resource Enhancement & Utilizat Technol Div, Manchester Res Stn, POB 130, Manchester, WA 98353 USA. NR 32 TC 69 Z9 71 U1 0 U2 26 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0378-1909 J9 ENVIRON BIOL FISH JI Environ. Biol. Fishes PD JUL PY 2003 VL 67 IS 3 BP 241 EP 251 DI 10.1023/A:1025887015436 PG 11 WC Ecology; Marine & Freshwater Biology SC Environmental Sciences & Ecology; Marine & Freshwater Biology GA 724AF UT WOS:000185463400003 ER PT J AU Currie, JD Shelton, RO AF Currie, JD Shelton, RO TI The set of k-power free words over Sigma is empty or perfect SO EUROPEAN JOURNAL OF COMBINATORICS LA English DT Article ID APERIODIC WORDS; 3 SYMBOLS AB The authors show that for a natural number k and a finite alphabet Sigma the set of omega-words over Sigma avoiding x(k) is either empty or perfect. This leads to an algorithm to determine which k-power free words over Sigma extend to k-power free omega-words over Sigma. (C) 2003 Elsevier Science Ltd. All rights reserved. C1 Univ Winnipeg, Dept Math & Stat, Winnipeg, MB R3B 2E9, Canada. NASA, Informat Syst Directorate, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Currie, JD (reprint author), Univ Winnipeg, Dept Math & Stat, Winnipeg, MB R3B 2E9, Canada. NR 11 TC 2 Z9 2 U1 0 U2 0 PU ACADEMIC PRESS LTD ELSEVIER SCIENCE LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 0195-6698 J9 EUR J COMBIN JI Eur. J. Comb. PD JUL PY 2003 VL 24 IS 5 BP 573 EP 580 DI 10.1016/S0195-6698(03)00044-1 PG 8 WC Mathematics SC Mathematics GA 694EC UT WOS:000183760000010 ER PT J AU Figueroa, F St Cyr, W Van Dyke, D McVay, G Mitchell, M AF Figueroa, F St Cyr, W Van Dyke, D McVay, G Mitchell, M TI Evaluation of white light Fabry-Perot interferometry fiber-optic gages for small strains SO EXPERIMENTAL TECHNIQUES LA English DT Article C1 NASA, Stennis Space Ctr, MS USA. Lockheed Martin Space Org, Stennis Space Ctr, MS USA. RP Figueroa, F (reprint author), NASA, Stennis Space Ctr, MS USA. NR 5 TC 0 Z9 0 U1 0 U2 2 PU SOC EXPERIMENTAL MECHANICS PI BETHEL PA 7 SCHOOL STREET, BETHEL, CT 06801 USA SN 0732-8818 J9 EXP TECHNIQUES JI Exp. Tech. PD JUL-AUG PY 2003 VL 27 IS 4 BP 31 EP 36 DI 10.1111/j.1747-1567.2003.tb00120.x PG 6 WC Engineering, Mechanical; Mechanics; Materials Science, Characterization & Testing SC Engineering; Mechanics; Materials Science GA 712NE UT WOS:000184803100008 ER PT J AU Newman, JA Riddell, WT Piascik, RS AF Newman, JA Riddell, WT Piascik, RS TI A threshold fatigue crack closure model: Part I - model development SO FATIGUE & FRACTURE OF ENGINEERING MATERIALS & STRUCTURES LA English DT Article DE crack tip; fatigue crack closure; oxide; plasticity; roughness; threshold ID STRESS INTENSITIES; THEORETICAL-MODEL; GROWTH; DISLOCATION; ROUGHNESS; ALUMINUM; PROPAGATION; ENVIRONMENT; STRENGTH; BEHAVIOR AB A fatigue crack closure model is developed that includes the effects of, and interactions between, the three closure mechanisms most likely to occur at threshold; plasticity, roughness, and oxide. This model, herein referred to as the CROP model (for Closure, Roughness, Oxide, and Plasticity), also includes the effects of out-of-plane cracking and multi-axial loading. These features make the CROP closure model uniquely suited for, but not limited to, threshold applications. Rough cracks are idealized here as two-dimensional sawtooths, whose geometry induces mixed-mode crack-tip stresses. Continuum mechanics and crack-tip dislocation concepts are combined to relate crack face displacements to crack-tip loads. Geometric criteria are used to determine closure loads from crack-face displacements. Finite element results, used to verify model predictions, provide critical information about the locations where crack closure occurs. The CROP model is verified with experimental data in part II of this paper. C1 USA, Res Lab, Vehicle Technol Directorate, Hampton, VA 23681 USA. Volpe Natl Transportat Syst Ctr, Cambridge, MA 02142 USA. NASA, Langley Res Ctr, Met & Thermal Struct Branch, Hampton, VA 23681 USA. Virginia Tech, Blacksburg, VA USA. RP Newman, JA (reprint author), USA, Res Lab, Vehicle Technol Directorate, Hampton, VA 23681 USA. NR 48 TC 11 Z9 11 U1 1 U2 4 PU BLACKWELL PUBLISHING LTD PI OXFORD PA 9600 GARSINGTON RD, OXFORD OX4 2DG, OXON, ENGLAND SN 8756-758X J9 FATIGUE FRACT ENG M JI Fatigue Fract. Eng. Mater. Struct. PD JUL PY 2003 VL 26 IS 7 BP 603 EP 614 DI 10.1046/j.1460-2695.2003.00660.x PG 12 WC Engineering, Mechanical; Materials Science, Multidisciplinary SC Engineering; Materials Science GA 692XW UT WOS:000183686400004 ER PT J AU Newman, JA Riddell, WT Piascik, RS AF Newman, JA Riddell, WT Piascik, RS TI A threshold fatigue crack closure model: Part II - experimental verification SO FATIGUE & FRACTURE OF ENGINEERING MATERIALS & STRUCTURES LA English DT Article DE crack tip; fatigue crack closure; oxide; plasticity; roughness; threshold ID FRACTURE SURFACE-ROUGHNESS; THEORETICAL-MODEL; GROWTH; ALUMINUM; BEHAVIOR AB Predictions from an analytical model that considers contributions and interactions between plasticity, roughness, and oxide induced crack closure are presented and compared with experimental data. The analytical model is shown to correctly predict the combined influences of crack roughness, oxide debris, and plasticity in the near-threshold regime. Furthermore, analytical results indicate closure mechanisms interact in a non-linear manner such that the total amount of closure is not the sum of closure contributions for each mechanism. C1 USA, Res Lab, Vehicle Technol Directorate, Hampton, VA 23681 USA. Volpe Natl Transportat Syst Ctr, Cambridge, MA 02142 USA. NASA, Langley Res Ctr, Met & Thermal Struct Branch, Hampton, VA 23681 USA. Virginia Tech, Blacksburg, VA USA. RP Newman, JA (reprint author), USA, Res Lab, Vehicle Technol Directorate, Hampton, VA 23681 USA. NR 31 TC 5 Z9 5 U1 0 U2 1 PU BLACKWELL PUBLISHING LTD PI OXFORD PA 9600 GARSINGTON RD, OXFORD OX4 2DG, OXON, ENGLAND SN 8756-758X J9 FATIGUE FRACT ENG M JI Fatigue Fract. Eng. Mater. Struct. PD JUL PY 2003 VL 26 IS 7 BP 615 EP 625 DI 10.1046/j.1460-2695.2003.00635.x PG 11 WC Engineering, Mechanical; Materials Science, Multidisciplinary SC Engineering; Materials Science GA 692XW UT WOS:000183686400005 ER PT J AU Hanselman, DH Quinn, TJ Lunsford, C Heifetz, J Clausen, D AF Hanselman, DH Quinn, TJ Lunsford, C Heifetz, J Clausen, D TI Applications in adaptive cluster sampling of Gulf of Alaska rockfish SO FISHERY BULLETIN LA English DT Article ID EFFICIENCY; ABUNDANCE AB Adaptive cluster sampling (ACS) has been the subject of many publications about sampling aggregated populations. Choosing the criterion value that invokes ACS remains problematic. We address this problem using data from a June 1999 ACS survey for rockfish, specifically for Pacific ocean perch (,Sebastes alutus), and for shortraker (S. borealis) and rougheye (S. aleutianus) rockfish combined. Our hypotheses were that ACS would outperform simple random sampling (SRS) for S. alutus and would be more applicable for S. alutus than for S. borealis and S. aleutianus combined because populations of S. alutus are thought to be more aggregated. Three alternatives for choosing a criterion value were investigated. We chose the strategy that yielded the lowest criterion value and simulated the higher criterion values with the data after the survey. Systematic random sampling was conducted across the whole area to determine the lowest criterion value, and then a new systematic random sample was taken with adaptive sampling around each tow that exceeded the fixed criterion value. ACS yielded gains in precision (SE) over SRS. Bootstrapping showed that the distribution of an ACS estimator is approximately normal, whereas the SRS sampling distribution is skewed and bimodal. Simulation showed that a higher criterion value results in substantially less adaptive sampling with little tradeoff in precision. When time-efficiency was examined, ACS quickly added more samples, but sampling edge units caused this efficiency to be lessened, and the gain in efficiency did not measurably affect our conclusions. ACS for S. alutus should be incorporated with a fixed criterion value equal to the top quartile of previously collected survey data. The second hypothesis was confirmed because ACS did not prove to be more effective for S. borealis-S. aleutianus. Overall, our ACS results were not as optimistic as those previously published in the literature, and indicate the need for further study of this sampling method. C1 Univ Alaska, Sch Fisheries & Ocean Sci, Juneau, AK 99801 USA. Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr, Auke Bay Lab, Juneau, AK 99801 USA. RP Hanselman, DH (reprint author), Univ Alaska, Sch Fisheries & Ocean Sci, 11275 Glacier Hwy, Juneau, AK 99801 USA. NR 13 TC 28 Z9 30 U1 0 U2 1 PU NATL MARINE FISHERIES SERVICE SCIENTIFIC PUBL OFFICE PI SEATTLE PA 7600 SAND POINT WAY NE BIN C15700, SEATTLE, WA 98115 USA SN 0090-0656 J9 FISH B-NOAA JI Fish. Bull. PD JUL PY 2003 VL 101 IS 3 BP 501 EP 513 PG 13 WC Fisheries SC Fisheries GA 707WE UT WOS:000184532200004 ER PT J AU Mullin, KD Fulling, GL AF Mullin, KD Fulling, GL TI Abundance of cetaceans in the southern US North Atlantic Ocean during summer 1998 SO FISHERY BULLETIN LA English DT Article ID GULF-OF-MEXICO; CONTINENTAL-SLOPE; AERIAL AB The US. Marine Mammal Protection Act requires that the abundance of marine mammals in U.S. waters be assessed. Because this requirement had not been met for a large portion of the North Atlantic Ocean (U.S. waters south of Maryland), a ship-based, line-transect survey was conducted with a 68 m research ship between Maryland (38.00degreesN) and central Florida (28.00degreesN) from the 10-m isobath to the boundary of the U.S. Exclusive Economic Zone. The study area (573,000 km(2)) was surveyed between 8 July and 17 August 1998. Minimum abundance estimates were based on 4163 km of effort and 217 sightings of at least 13 cetacean species and other taxonomic categories. The most commonly sighted species (number of groups) were bottlenose dolphins, Tursiops truncatus (38); sperm whales, Physeter macrocephalus (29); Atlantic spotted dolphins, Stenella frontalis (28); and Risso's dolphins, Grampus griseus (22). The most abundant species (abundance; coefficient of variation) were Atlantic spotted dolphins (14,438; 0.63); bottlenose dolphins (13,085; 0.40); pantropical spotted dolphins, S. attenuata (12,747; 0.56); striped dolphins, S. coeruleoalba (10,225; 0.91); and Risso's dolphins (9533; 0.50). The abundance estimate for the Clymene dolphin, S. clymene (6086; 0.93), is the first for the U.S. Atlantic Ocean. Sperm whales were the most abundant large whale (1181; 0.51). Abundances for other species or taxonomic categories ranged from 20 to 5109. There were an estimated 77,139 (0.23) cetaceans in the study area. Bottlenose dolphins and Atlantic spotted dolphins were encountered primarily in continental shelf (<200 m) and continental slope waters (200-2000 m). All other species were generally sighted in oceanic waters (>200 m). The distribution of some species varied north to south. Striped dolphins, Clymene dolphins, and sperm whales were sighted primarily in the northern part of the study area; whereas pantropical spotted dolphins were sighted primarily in the southern portion. C1 NOAA, Natl Marine Fisheries Serv, SE Fisheries Sci Ctr, Pascagoula, MS 39567 USA. RP Mullin, KD (reprint author), NOAA, Natl Marine Fisheries Serv, SE Fisheries Sci Ctr, 3209 Frederic St, Pascagoula, MS 39567 USA. NR 30 TC 20 Z9 24 U1 0 U2 1 PU NATL MARINE FISHERIES SERVICE SCIENTIFIC PUBL OFFICE PI SEATTLE PA 7600 SAND POINT WAY NE BIN C15700, SEATTLE, WA 98115 USA SN 0090-0656 J9 FISH B-NOAA JI Fish. Bull. PD JUL PY 2003 VL 101 IS 3 BP 603 EP 613 PG 11 WC Fisheries SC Fisheries GA 707WE UT WOS:000184532200011 ER PT J AU House, CH Runnegar, B Fitz-Gibbon, ST AF House, Christopher H. Runnegar, Bruce Fitz-Gibbon, Sorel T. TI Geobiological analysis using whole genome-based tree building applied to the Bacteria, Archaea, and Eukarya SO GEOBIOLOGY LA English DT Article AB We constructed genomic trees based on the presence and absence of families of protein-encoding genes observed in 55 prokaryotic and five eukaryotic genomes. There are features of the genomic trees that are not congruent with typical rRNA phylogenetic trees. In the bacteria, for example, Deinococcus radiodurans associates with the Gram-positive bacteria, a result that is also seen in some other phylogenetic studies using whole genome data. In the Archaea, the methanogens plus Archaeoglobus form a united clade and the Euryarchaeota are divided with the two Thermoplasma genomes and Halobacterium sp. falling below the Crenarchaeota. While the former appears to be an accurate representation of methanogen-relatedness, the misplacement of Halobacterium may be an artefact of parsimony. These results imply the last common ancestor of the Archaea was not a methanogen, leaving sulphur reduction as the most geochemically plausible metabolism for the base of the archaeal crown group. It also suggests that methanogens were not a component of the Earth's earliest biosphere and that their origin occurred sometime during the Archean. In the Eukarya, the parsimony analysis of five Eukaryotes using the Crenarchaeota as an outgroup seems to counter the Ecdysozoa hypothesis, placing Caenorhabditis elegans (Nematoda) below the common ancestor of Drosophila melanogaster (Arthropoda) and Homo sapiens (Chordata) even when efforts are made to counter the possible effects of a faster rate of sequence evolution for the C. elegans genome. Further analysis, however, suggests that the gene loss of 'animal' genes is highest in C. elegans and is obscuring the relationships of these organisms. C1 [House, Christopher H.] Penn State Univ, Penn State Astrobiol Res Ctr, University Pk, PA 16802 USA. [House, Christopher H.] Penn State Univ, Dept Geosci, University Pk, PA 16802 USA. [Runnegar, Bruce] Univ Calif Los Angeles, Inst Geophys & Planetary Phys, Los Angeles, CA 90095 USA. [Runnegar, Bruce] Univ Calif Los Angeles, NASA, Astrobiol Inst, Los Angeles, CA 90095 USA. [Fitz-Gibbon, Sorel T.] Univ Calif Los Angeles, IGPP Ctr Astrobiol, Los Angeles, CA 90095 USA. RP House, CH (reprint author), Penn State Univ, Penn State Astrobiol Res Ctr, 212 Deike Bldg, University Pk, PA 16802 USA. EM chouse@geosc.psu.edu FU NASA Astrobiology Institute (NAI) FX This research was supported by NASA Astrobiology Institute (NAI) grants to the Penn State Astrobiology Research Center and to the UCLA Center for Astrobiology. IGPP Publication no. 5780 NR 60 TC 26 Z9 29 U1 1 U2 10 PU WILEY-BLACKWELL PUBLISHING, INC PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 1472-4677 J9 GEOBIOLOGY JI Geobiology PD JUL PY 2003 VL 1 IS 1 BP 15 EP 26 DI 10.1046/j.1472-4669.2003.00004.x PG 12 WC Biology; Environmental Sciences; Geosciences, Multidisciplinary SC Life Sciences & Biomedicine - Other Topics; Environmental Sciences & Ecology; Geology GA V06CG UT WOS:000207171100003 ER PT J AU Righter, K Shearer, CK AF Righter, K Shearer, CK TI Magmatic fractionation of Hf and W: Constraints on the timing of core formation and differentiation in the Moon and Mars SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Article ID OXYGEN FUGACITY; SIDEROPHILE ELEMENTS; SILICATE MELT; HIGH-PRESSURE; PARTITIONING BEHAVIOR; TERRESTRIAL ACCRETION; CHEMICAL EVOLUTION; RAPID ACCRETION; BASALTIC LIQUID; SNC METEORITES AB Excesses of W-182 have previously been measured in samples from the Moon and Mars, and can be derived from high Hf/W regions in their interiors during their early histories. Although planetary mantles will have superchondritic Hf/W after core formation, the extent to which high Hf/W regions could be generated by magmatic fractionation has not been evaluated. In order to address the latter possibility, we have carried out experiments from 100 MPa to 10.0 GPa, 1150 to 1850degreesC, at oxygen fugacities near the IW (iron-wustite) buffer, and measured partition coefficients for W and Hf for plagioclase-liquid, olivine-liquid, orthopyroxene-liquid, clinopyroxene-liquid, garnet-liquid, and metal-liquid pairs. Clinopyroxene and garnet are both capable of fractionating Hf from W during magmatic crystallization or mantle melting, and minor variations in the measured D's can be attributed to crystal chemical effects. Excesses of W-182 and Nd-142 in lunar samples can be explained by fractionation of Hf from W, and Sm from Nd (by ilmenite and clinopyroxene) during crystallization of the latest stages of a lunar magma ocean. Correlations of epsilon(w) with epsilon(Nd), in martian samples could be a result of early silicate fractionation in the martian mantle (clinopyroxene and/or garnet). Copyright (C) 2003 Elsevier Science Ltd. C1 Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. Univ New Mexico, Dept Earth & Planetary Sci, Inst Meteorit, Albuquerque, NM 87122 USA. RP Righter, K (reprint author), NASA, Lyndon B Johnson Space Ctr, 2101 NASA Rd 1, Houston, TX 77058 USA. EM righter@lpl.arizona.edu NR 79 TC 65 Z9 65 U1 1 U2 9 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 JUL PY 2003 VL 67 IS 13 BP 2497 EP 2507 DI 10.1016/S0016-7037(02)01349-2 PG 11 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 693MF UT WOS:000183720800021 ER PT J AU Orphan, VJ Goffredi, SK Delong, EF Boles, JR AF Orphan, VJ Goffredi, SK Delong, EF Boles, JR TI Geochemical influence on diversity and microbial processes in high temperature oil reservoirs SO GEOMICROBIOLOGY JOURNAL LA English DT Article DE methanogenesis; petroleum; subsurface; thermophile ID SAN-JOAQUIN BASIN; PETROLEUM RESERVOIRS; SP-NOV; GEN. NOV.; NORTH-SEA; ARCHAEA; BACTERIA; FIELD; CALIFORNIA; OXIDATION AB The diversity of thermophilic microbial assemblages detected within two neighboring high temperature petroleum formations was shown to closely parallel the different geochemical regimes existing in each. A high percentage of archaeal 16S rRNA gene sequences, related to thermophilic aceticlastic and hydrogenotrophic methanogens, were detected in the natural gas producing Rincon Formation. In contrast, rRNA gene libraries from the highly sulfidogenic Monterey Formation contained primarily sulfur-utilizing and fermentative archaea and bacteria. In addition to the variations in microbial community structure, microbial activities measured in microcosm experiments using high temperature production fluids from oil-bearing formations also demonstrated fundamental differences in the terminal respiratory and redox processes. Provided with the same suite of basic energy substrates, production fluids from the South Elwood Rincon Formation actively generated methane, while thermophilic microflora within the Monterey production fluids were dominated by hydrogen sulfide producing microorganisms. In both cases, molecular hydrogen appeared to play a central role in the stimulation of carbon and sulfur cycling in these systems. In methanogenic production fluids, the addition of sulfur compounds induced a rapid shift in the terminal electron accepting process, stimulating hydrogen sulfide formation and illustrating the metabolic versatility of the subsurface thermophilic assemblage. The high similarity between microbial community structure and activity corresponding with the prevalent geochemical conditions observed in deep subsurface petroleum reservoirs suggests that the resident microflora have adapted to the subsurface physicochemical conditions and may actively influence the geochemical environment in situ. C1 Monterey Bay Aquarium Res Inst, Moss Landing, CA USA. Univ Calif Santa Barbara, Dept Geol Sci, Santa Barbara, CA 93106 USA. RP Orphan, VJ (reprint author), NASA, Ames Res Ctr, Mail Stop 239-4, Moffett Field, CA 94035 USA. EM vorphan@mail.arc.nasa.gov RI Orphan, Victoria/K-1002-2014 OI Orphan, Victoria/0000-0002-5374-6178 NR 39 TC 36 Z9 42 U1 1 U2 12 PU TAYLOR & FRANCIS INC PI PHILADELPHIA PA 325 CHESTNUT ST, SUITE 800, PHILADELPHIA, PA 19106 USA SN 0149-0451 J9 GEOMICROBIOL J JI Geomicrobiol. J. PD JUL-AUG PY 2003 VL 20 IS 4 BP 295 EP 311 DI 10.1080/01490450303898 PG 17 WC Environmental Sciences; Geosciences, Multidisciplinary SC Environmental Sciences & Ecology; Geology GA 708NZ UT WOS:000184575800003 ER PT J AU Righter, K AF Righter, K TI Meteorites SO GEOTIMES LA English DT Article C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Righter, K (reprint author), NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. EM kevin.righter-l@nasa.gov NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER GEOLOGICAL INST PI ALEXANDRIA PA 4220 KING ST, ALEXANDRIA, VA 22302-1507 USA SN 0016-8556 J9 GEOTIMES JI Geotimes PD JUL PY 2003 VL 48 IS 7 BP 36 EP 36 PG 1 WC Geosciences, Multidisciplinary SC Geology GA 779XA UT WOS:000189326300035 ER PT J AU Bowling, LC Lettenmaier, DP Nijssen, B Graham, LP Clark, DB El Maayar, M Essery, R Goers, S Gusev, YM Habets, F van den Hurk, B Jin, JM Kahan, D Lohmann, D Ma, XY Mahanama, S Mocko, D Nasonova, O Niu, GY Samuelsson, P Shmakin, AB Takata, K Verseghy, D Viterbo, P Xia, YL Xue, YK Yang, ZL AF Bowling, LC Lettenmaier, DP Nijssen, B Graham, LP Clark, DB El Maayar, M Essery, R Goers, S Gusev, YM Habets, F van den Hurk, B Jin, JM Kahan, D Lohmann, D Ma, XY Mahanama, S Mocko, D Nasonova, O Niu, GY Samuelsson, P Shmakin, AB Takata, K Verseghy, D Viterbo, P Xia, YL Xue, YK Yang, ZL TI Simulation of high-latitude hydrological processes in the Torne-Kalix basin: PILPS phase 2(e) - 1: Experiment description and summary intercomparisons SO GLOBAL AND PLANETARY CHANGE LA English DT Article DE Arctic regions; modelling; hydrology; atmosphere ID SURFACE PARAMETERIZATION SCHEMES; LAND-SURFACE; FRESH-WATER; ENERGY-BALANCE; RIVER BASIN; MODEL; SNOW; PROJECT; IMPACT; REPRESENTATION AB Twenty-one land-surface schemes (LSSs) participated in the Project for Intercomparison of Land-surface Parameterizations (PILPS) Phase 2(e) experiment, which used data from the Tome-Kalix Rivers in northern Scandinavia. Atmospheric forcing data (precipitation, air temperature, specific humidity, wind speed, downward shortwave and longwave radiation) for a 20-year period (1979-1998) were provided to the 21 participating modeling groups for 218 1/4degrees grid cells that represented the study domain. The first decade (1979-1988) of the period was used for model spin-up. The quality of meteorologic forcing variables is of particular concern in high-latitude experiments and the quality of the gridded dataset was assessed to the extent possible. The lack of sub-daily precipitation, underestimation of true precipitation and the necessity to estimate incoming solar radiation were the primary data concerns for this study. The results from two of the three types of runs are analyzed in this, the first of a three-part paper: (1) calibration-validation runs-calibration of model parameters using observed streamflow was allowed for two small catchments (570 and 1300 km(2)), and parameters were then transferred to two other catchments of roughly similar size (2600 and 1500 km(2)) to assess the ability of models to represent ungauged areas elsewhere; and 2) reruns-using revised forcing data (to resolve problems with apparent underestimation of solar radiation of approximately 36%, and certain other problems with surface wind in the original forcing data). Model results for the period 1989-1998 are used to evaluate the performance of the participating land-surface schemes in a context that allows exploration of their ability to capture key processes spatially. In general, the experiment demonstrated that many of the LSSs are able to capture the limitations imposed on annual latent heat by the small net radiation available in this high-latitude environment. Simulated annual average net radiation varied between 16 and 40 W/m(2) for the 21 models, and latent heat varied between 18 and 36 W/m(2). Among-model differences in winter latent heat due to the treatment of aerodynamic resistance appear to be at least as important as those attributable to the treatment of canopy interception. In many models, the small annual net radiation forced negative sensible heat on average, which varied among the models between - 11 and 9 W/m(2). Even though the largest evaporation rates occur in the summer (June, July and August), model-predicted snow sublimation in winter has proportionately more influence on differences in annual runoff volume among the models. A calibration experiment for four small sub-catchments of the Torne-Kalix basin showed that model parameters that are typically adjusted during calibration, those that control storage of moisture in the soil column or on the land surface via ponding, influence the seasonal distribution of runoff, but have relatively little impact on annual runoff ratios. Similarly, there was no relationship between annual runoff ratios and the proportion of surface and subsurface discharge for the basin as a whole. (C) 2003 Elsevier Science B.V. All rights reserved. C1 Swedish Meteorol & Hydrol Inst, Gothenburg, Sweden. Ctr Ecol & Hydrol, Wallingford, Oxon, England. Canadian Forest Serv, No Forestry Ctr, Edmonton, AB, Canada. GKSS Forschungszentrum Geesthacht GmbH, Geesthacht, Germany. Russian Acad Sci, Russian Federat, Inst Water Problems, Moscow 117901, Russia. Natl Ctr Atmospher Res, CNRM, Toulouse, France. Royal Netherlands Meteorol Inst, NL-3730 AE De Bilt, Netherlands. Univ Arizona, Dept Hydrol & Water Resources, Tucson, AZ 85721 USA. Univ Calif Los Angeles, Torrance, CA 90509 USA. NASA, Goddard Space Flight Ctr, Hydrol Sci Branch, Baltimore, MD USA. Univ Maryland Baltimore Cty, GEST, Baltimore, MD 21228 USA. Stockholm Univ, Dept Meteorol, S-10691 Stockholm, Sweden. Russian Acad Sci, Inst Geog, Moscow, Russia. European Ctr Medium Range Weather Forecasts, Reading RG2 9AX, Berks, England. Macquarie Univ, N Ryde, NSW, Australia. Univ Washington, Dept Civil & Environm Engn, Seattle, WA 98195 USA. RP Bowling, LC (reprint author), Univ Washington, Dept Civil & Environm Engn, Box 352700, Seattle, WA 98195 USA. EM lxb@hydro.washington.edu RI Nasonova, Olga/B-6093-2014; gusev, yugeniy/G-4711-2014; Niu, Guo-Yue/B-8317-2011; Clark, Douglas/A-6102-2010; Viterbo, Pedro/B-7184-2008; Yang, Zong-Liang/B-4916-2011; Jin, Jiming/A-9678-2011; Bowling, Laura/B-6963-2013; lettenmaier, dennis/F-8780-2011; Nijssen, Bart/B-1013-2012; OI gusev, yugeniy/0000-0003-3886-2143; Clark, Douglas/0000-0003-1348-7922; Viterbo, Pedro/0000-0001-6587-3062; Bowling, Laura/0000-0002-1439-3154; lettenmaier, dennis/0000-0003-3317-1327; Nijssen, Bart/0000-0002-4062-0322; Habets, Florence/0000-0003-1950-0921; Essery, Richard/0000-0003-1756-9095 NR 78 TC 127 Z9 135 U1 0 U2 19 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-8181 EI 1872-6364 J9 GLOBAL PLANET CHANGE JI Glob. Planet. Change PD JUL PY 2003 VL 38 IS 1-2 BP 1 EP 30 DI 10.1016/S0921-8181(03)00003-1 PG 30 WC Geography, Physical; Geosciences, Multidisciplinary SC Physical Geography; Geology GA 706EC UT WOS:000184439000002 ER PT J AU Nijssen, B Bowling, LC Lettenmaier, DP Clark, DB El Maayar, M Essery, R Goers, S Gusev, YM Habets, F van den Hurk, B Jin, JM Kahan, D Lohmann, D Ma, XY Mahanama, S Mocko, D Nasonova, O Niu, GY Samuelsson, P Schmakin, AB Takata, K Verseghy, D Viterbo, P Xia, YL Xue, YK Yang, ZL AF Nijssen, B Bowling, LC Lettenmaier, DP Clark, DB El Maayar, M Essery, R Goers, S Gusev, YM Habets, F van den Hurk, B Jin, JM Kahan, D Lohmann, D Ma, XY Mahanama, S Mocko, D Nasonova, O Niu, GY Samuelsson, P Schmakin, AB Takata, K Verseghy, D Viterbo, P Xia, YL Xue, YK Yang, ZL TI Simulation of high latitude hydrological processes in the Torne-Kalix basin: PILPS phase 2(e) - 2: Comparison of model results with observations SO GLOBAL AND PLANETARY CHANGE LA English DT Article DE Tome-Kalix basin; PILPS phase 2(e); hydrological processes ID PARAMETERIZATION SCHEMES PILPS; SNOW; PROJECT AB Model results from 21 land-surface schemes (LSSs) designed for use in numerical weather prediction and climate models are compared with each other and with observations in the context of the Project for Intercomparison of Land-surface Parameterization Schemes (PILPS) Phase 2(e) model intercomparison experiment. This experiment focuses on simulations of land-surface water and energy fluxes in the 58,000-km(2) Tome and Kalix river systems in northern Scandinavia, during the period 1989-1998. All models participating in PILPS Phase 2(e) capture the broad dynamics of snowmelt and runoff, but large differences in snow accumulation and ablation, turbulent heat fluxes, and strearnflow exist. The greatest among-model differences in energy and moisture fluxes in these high-latitude environments occur during the spring snowmelt period, reflecting different model parameterizations of snow processes. Differences in net radiation are governed by differences in the simulated radiative surface temperature during the winter months and by differences in surface albedo during the spring/early summer. Differences in net radiation are smallest during the late summer when snow is absent. Although simulated snow sublimation is small for most models, a few models show annual snow sublimation of about 100 mm. These differences in snow sublimation appear to be largely dependent on differences in snow surface roughness parameterizations. The models with high sublimation generally lose their snowpacks too early compared to observations and underpredict the annual runoff. Differences in runoff parameterizations are reflected in differences in daily runoff statistics. Although most models show a greater variability in daily strearnflow than the observations, the models with the greatest variability (as much as double the observed variability), produce most of their runoff through fast response, surface runoff mechanisms. As a group, those models that took advantage of an opportunity to calibrate to selected small catchments and to transfer calibration results to the basin at large had a smaller bias and root mean squared error (RMSE) in daily streamflow simulations compared with the models that did not calibrate. (C) 2003 Elsevier Science B.V. All rights reserved. C1 Univ Arizona, Dept Hydrol & Water Resources, Tucson, AZ 85721 USA. Univ Washington, Dept Civil & Environm Engn, Seattle, WA 98195 USA. Ctr Ecol & Hydrol, Wallingford, Oxon, England. Canadian Forest Serv, No Forestry Ctr, Edmonton, AB, Canada. GKSS Forschungszentrum Geesthacht GmbH, Geesthacht, Germany. Russian Acad Sci, Inst Water Problems, Moscow 117901, Russia. Natl Ctr Atmospher Res, CNRM, Toulouse, France. Royal Netherlands Meteorol Inst, NL-3730 AE De Bilt, Netherlands. Univ Calif Los Angeles, Torrance, CA 90509 USA. NOAA, Environm Modeling Ctr, NCEP, NSW, Washington, DC USA. NASA, Goddard Space Flight Ctr, Hydrol Sci Branch, Baltimore, MD USA. Univ Maryland Baltimore Cty, GEST, Baltimore, MD USA. Univ Stockholm, Dept Meteorol, S-10691 Stockholm, Sweden. Russian Acad Sci, Inst Geog, Moscow, Russia. European Ctr Medium Range Weather Forecasts, Reading RG2 9AX, Berks, England. Macquarie Univ, N Ryde, NSW, Australia. Univ Texas, Dept Geol Sci, Austin, TX USA. RP Nijssen, B (reprint author), Univ Arizona, Dept Civil Engn & Engn Mech, JW Harshbarger 320A,POB 210011, Tucson, AZ 85721 USA. EM nijssen@u.arizona.edu RI Clark, Douglas/A-6102-2010; Viterbo, Pedro/B-7184-2008; Yang, Zong-Liang/B-4916-2011; Jin, Jiming/A-9678-2011; Bowling, Laura/B-6963-2013; lettenmaier, dennis/F-8780-2011; Nasonova, Olga/B-6093-2014; gusev, yugeniy/G-4711-2014; Nijssen, Bart/B-1013-2012; Niu, Guo-Yue/B-8317-2011; OI Clark, Douglas/0000-0003-1348-7922; Viterbo, Pedro/0000-0001-6587-3062; Bowling, Laura/0000-0002-1439-3154; lettenmaier, dennis/0000-0003-3317-1327; gusev, yugeniy/0000-0003-3886-2143; Nijssen, Bart/0000-0002-4062-0322; Habets, Florence/0000-0003-1950-0921; Essery, Richard/0000-0003-1756-9095 NR 15 TC 76 Z9 82 U1 0 U2 14 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-8181 EI 1872-6364 J9 GLOBAL PLANET CHANGE JI Glob. Planet. Change PD JUL PY 2003 VL 38 IS 1-2 BP 31 EP 53 DI 10.1016/S0921-8181(03)00004-3 PG 23 WC Geography, Physical; Geosciences, Multidisciplinary SC Physical Geography; Geology GA 706EC UT WOS:000184439000003 ER PT J AU Bowling, LC Lettenmaier, DP Nijssen, B Polcher, J Koster, RD Lohmann, D AF Bowling, LC Lettenmaier, DP Nijssen, B Polcher, J Koster, RD Lohmann, D TI Simulation of high-latitude hydrological processes in the Torne-Kalix basin: PILPS phase 2(e) - 3: Equivalent model representation and sensitivity experiments SO GLOBAL AND PLANETARY CHANGE LA English DT Article DE arctic regions; modeling; hydrology; atmosphere ID LAND-SURFACE SCHEMES AB The Project for Intercomparison of Land Surface Parameterization Schemes (PILPS) Phase 2(e) showed that in cold regions the annual runoff production in Land Surface Schemes (LSSs) is closely related to the maximum snow accumulation, which in turn is controlled in large part by winter sublimation. To help further explain the relationship between snow cover, turbulent exchanges and runoff production, a simple equivalent model (SEM) was devised to reproduce the seasonal and annual fluxes simulated by 13 LSSs that participated in PILPS Phase 2(e). The design of the SEM relates the annual partitioning of precipitation and energy in the LSSs to three primary parameters: snow albedo, effective aerodynamic resistance and evaporation efficiency. Isolation of each of the parameters showed that the annual runoff production was most sensitive to the aerodynamic resistance. The SEM was somewhat successful in reproducing the observed LSS response to a decrease in shortwave radiation and changes in wind speed forcings. SEM parameters derived from the reduced shortwave forcings suggested that increased winter stability suppressed turbulent heat fluxes over snow. Because winter sensible heat fluxes were lamely negative, reductions in winter shortwave radiation resulted in an increase in annual average sensible beat. (C) 2003 Elsevier Science B.V. All rights reserved. C1 Univ Washington, Dept Civil & Environm Engn, Seattle, WA 98195 USA. CNRS, Meteorol Dynam Lab, Gif Sur Yvette, France. NASA, Goddard Space Flight Ctr, Lab Hydrospher Proc, Hydrol Sci Branch, Greenbelt, MD USA. NOAA, NCEP Environm Modeling Ctr, NSW, Washington, DC USA. RP Bowling, LC (reprint author), Univ Washington, Dept Civil & Environm Engn, Box 352700, Seattle, WA 98195 USA. RI Koster, Randal/F-5881-2012; Nijssen, Bart/B-1013-2012; Bowling, Laura/B-6963-2013; lettenmaier, dennis/F-8780-2011 OI Koster, Randal/0000-0001-6418-6383; Nijssen, Bart/0000-0002-4062-0322; Bowling, Laura/0000-0002-1439-3154; lettenmaier, dennis/0000-0003-3317-1327 NR 6 TC 15 Z9 15 U1 0 U2 2 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 JUL PY 2003 VL 38 IS 1-2 BP 55 EP 71 DI 10.1016/S0921-8181(03)00005-5 PG 17 WC Geography, Physical; Geosciences, Multidisciplinary SC Physical Geography; Geology GA 706EC UT WOS:000184439000004 ER PT J AU Potter, C Tan, PN Steinbach, M Klooster, S Kumar, V Myneni, R Genovese, V AF Potter, C Tan, PN Steinbach, M Klooster, S Kumar, V Myneni, R Genovese, V TI Major disturbance events in terrestrial ecosystems detected using global satellite data sets SO GLOBAL CHANGE BIOLOGY LA English DT Article DE carbon; climate; disturbance; ecosystems; remote sensing ID NET PRIMARY PRODUCTION; LAND-USE CHANGE; INTERANNUAL VARIATIONS; BRAZILIAN AMAZON; FIRE DETECTION; FOREST-FIRES; SCAR-B; CARBON; BIOMASS; EMISSIONS AB Ecosystem scientists have yet to develop a proven methodology to monitor and understand major disturbance events and their historical regimes at a global scale. This study was conducted to evaluate patterns in an 18-year record of global satellite observations of vegetation phenology from the Advanced Very High Resolution Radiometer (AVHRR) as a means to characterize major ecosystem disturbance events and regimes. The fraction absorbed of photosynthetically active radiation (FPAR) by vegetation canopies worldwide has been computed at a monthly time interval from 1982 to 1999 and gridded at a spatial resolution of 0.5degrees latitude/longitude. Potential disturbance events of large extent (>0.5 Mha) were identified in the FPAR time series by locating anomalously low values (FPAR-LO) that lasted longer than 12 consecutive months at any 0.5degrees pixel. We find that nearly 400 Mha of the global land surface could be identified with at least one FPAR-LO event over the 18-year time series. The majority of these potential disturbance events occurred in tropical savanna and shrublands or in boreal forest ecosystem classes. Verification of potential disturbance events from our FPAR-LO analysis was carried out using documented records of the timing of large-scale wildfires at locations throughout the world. Disturbance regimes were further characterized by association analysis with historical climate anomalies. Assuming accuracy of the FPAR satellite record to characterize major ecosystem disturbance events, we estimate that nearly 9 Pg of carbon could have been lost from the terrestrial biosphere to the atmosphere as a result of large-scale ecosystem disturbance over this 18-year time series. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ Minnesota, Minneapolis, MN USA. Calif State Univ Monterey Bay, Seaside, CA USA. Boston Univ, Boston, MA 02215 USA. RP Potter, C (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. EM cpotter@gaia.arc.nasa.gov RI Myneni, Ranga/F-5129-2012 NR 58 TC 63 Z9 63 U1 4 U2 19 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 1354-1013 J9 GLOBAL CHANGE BIOL JI Glob. Change Biol. PD JUL PY 2003 VL 9 IS 7 BP 1005 EP 1021 DI 10.1046/j.1365-2486.2003.00648.x PG 17 WC Biodiversity Conservation; Ecology; Environmental Sciences SC Biodiversity & Conservation; Environmental Sciences & Ecology GA 694VX UT WOS:000183796800004 ER PT J AU Vroom, PS Smith, CM Coyer, JA Walters, LJ Hunter, CL Beach, KS Smith, JE AF Vroom, PS Smith, CM Coyer, JA Walters, LJ Hunter, CL Beach, KS Smith, JE TI Field biology of Halimeda tuna (Bryopsidales, Chlorophyta) across a depth gradient: comparative growth, survivorship, recruitment, and reproduction SO HYDROBIOLOGIA LA English DT Article DE Halimeda tuna; coral reef; alizarin; Florida Keys; Ericthonius brasiliensis; Dictyota ID GREEN-ALGA-HALIMEDA; GREAT-BARRIER-REEF; SAN-SALVADOR ISLAND; CORAL-REEFS; FLORIDA-KEYS; SPECIES COMPOSITION; UNCHARTED SEAMOUNT; WATER; CALCIFICATION; CAULERPALES AB Growth, survivorship, recruitment, and reproduction of Halimeda tuna, a dominant green alga in many reef systems of the Florida Keys, were monitored at a shallow back reef ( 4 - 7m) and deep reef slope ( 15 - 22 m) on Conch Reef. Despite lower light intensities and similar grazing pressures, amphipod infestations, and epiphyte loads at both sites, the deeper site exhibited significantly higher growth rates in summer months over a 4-year period than found for the shallow population, possibly because of higher nutrient levels at depth and photoinhibition of shallow plants. Sexual reproductive events occurred simultaneously across the entire reef, with up to 5% of the population at both sites developing gametangia. New upright axes formed from zygotes, asexual fragmentation, or vegetative runners. Plants appear to have persistent basal stumps that survive harsh environmental conditions, even if upright, photosynthetic axes are removed. Sexual reproduction and 'smothering' by epiphyte overgrowth are hypothesized to be two causes of death for individuals. C1 Univ Hawaii Manoa, Dept Bot, Honolulu, HI 96822 USA. Univ Groningen, Dept Marine Biol, NL-9750 AA Haren, Netherlands. Univ Cent Florida, Dept Biol, Orlando, FL 32816 USA. Waikiki Aquarium, Honolulu, HI 96815 USA. Univ Tampa, Dept Biol, Tampa, FL 33606 USA. RP Vroom, PS (reprint author), Natl Marine Fisheries Serv, Kewalo Res Facil, 1125B Ala Moana Bvld, Honolulu, HI 96814 USA. RI Coyer, James/B-3295-2010; Smith, Jennifer/E-5207-2013 NR 65 TC 36 Z9 38 U1 1 U2 22 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0018-8158 J9 HYDROBIOLOGIA JI Hydrobiologia PD JUL PY 2003 VL 501 IS 1-3 BP 149 EP 166 DI 10.1023/A:1026287816324 PG 18 WC Marine & Freshwater Biology SC Marine & Freshwater Biology GA 734EG UT WOS:000186041800016 ER PT J AU Withers, P Bougher, SW Keating, GM AF Withers, P Bougher, SW Keating, GM TI The effects of topographically-controlled thermal tides in the martian upper atmosphere as seen by the MGS accelerometer SO ICARUS LA English DT Article DE Mars, atmosphere; tides, atmospheric; atmospheres, dynamics ID MARS GLOBAL SURVEYOR; LOWER THERMOSPHERE DENSITY; EMISSION SPECTROMETER; AEROBRAKING OPERATIONS; KELVIN WAVE; MODEL; CIRCULATION; SIMULATION; MISSION; STORM AB Mars Global Surveyor accelerometer observations of the martian upper atmosphere revealed large variations in density with longitude during northern hemisphere spring at altitudes of 130-160 km, all latitudes, and mid-afternoon local solar times (LSTs). This zonal structure is due to tides from the surface. The zonal structure is stable on timescales of weeks, decays with increasing altitude above 130 km, and is dominated by wave-3 (average amplitude 22% of mean density) and wave-2 (18%) harmonics. The phases of these harmonics are constant with both altitude and latitude, though their amplitudes change significantly with latitude. Near the South Pole, the phase of the wave-2 harmonic changes by 90degrees with a change of half a martian solar day while the wave-3 phase stays constant, suggesting diurnal and semidiurnal behaviour, respectively. We use a simple application of classical tidal theory to identify the dominant tidal modes and obtain results consistent with those of General Circulation Models. Our method is less rigorous, but simpler, than the General Circulation Models and hence complements them. Topography has a strong influence on the zonal structure. (C) 2003 Elsevier Inc. All rights reserved. C1 Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. Univ Michigan, AOSS Dept, Space Phys Res Lab, Ann Arbor, MI 48109 USA. George Washington Univ, NASA Langley, Hampton, VA 23681 USA. RP Withers, P (reprint author), Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. RI Bougher, Stephen/C-1913-2013; Withers, Paul/H-2241-2014 OI Bougher, Stephen/0000-0002-4178-2729; NR 49 TC 70 Z9 71 U1 2 U2 11 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 JUL PY 2003 VL 164 IS 1 BP 14 EP 32 DI 10.1016/S0019-1035(03)00135-0 PG 19 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 705AT UT WOS:000184374600002 ER PT J AU Emery, JP Brown, RH AF Emery, JP Brown, RH TI Constraints on the surface composition of Trojan asteroids from near-infrared (0.8-4.0 mu m) spectroscopy SO ICARUS LA English DT Article DE asteroids, composition; infrared observations; organic chemistry; spectroscopy; surfaces, asteroids ID CHARGED-PARTICLE IRRADIATION; CCD REFLECTANCE SPECTRA; SOLAR-SYSTEM; OPTICAL-CONSTANTS; ICE ANALOGS; THERMAL EVOLUTION; OUTER-BELT; SATELLITES; DARK; HYDROCARBONS AB We present new near-infrared spectra of 20 Trojan asteroids. The spectra were recorded at the NASA Infrared Telescope Facility (IRTF) using the recently commissioned medium-resolution spectrograph SpeX and at the Multiple Mirror Telescope (MMT) using the instrument FSPEC. Spectra of all of these objects were measured in K-band (1.95-2.5 mum), 8 of these in L-band (2.8-4.0 mum), and 14 in the range 0.8-2.5 mum. These observations nearly double the number of published 0.8-2.5 mum spectra of Trojan asteroids and provide the first systematic study of the L-band region for these distant asteroids. The data show that the red spectral slope measured in the near-IR extends through the L-band, though it is not as steep here as at shorter wavelengths. A significant diversity is apparent in the near-IR spectral slopes of this sampling of objects. Most of the spectra do not contain any definitive absorption features characteristic of surface composition (e.g., H2O, organics, silicates) as seen on main-belt asteroids and several Centaur and Kuiper Belt objects. A few objects may display spectral activity, and the reliability of these possible features is discussed. While these spectra are generally compatible with silicate surfaces to explain the spectral slope mixed with some fraction of low albedo material, there is no absolute indication of silicates. The spectral slope could also be explained by the presence of hydrocarbons, but the lack of absorption features, especially in L-band where very strong fundamental absorptions from these molecules appear, constrains the character and abundance of these materials at the surface. (C) 2003 Elsevier Inc. All rights reserved. C1 Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. RP Emery, JP (reprint author), NASA, Washington, DC 20546 USA. NR 70 TC 62 Z9 62 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 JUL PY 2003 VL 164 IS 1 BP 104 EP 121 DI 10.1016/S0019-1035(03)00143-X PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 705AT UT WOS:000184374600007 ER PT J AU Cuzzi, JN Hogan, RC AF Cuzzi, JN Hogan, RC TI Blowing in the wind I. Velocities of chondrule-sized particles in a turbulent protoplanetary nebula SO ICARUS LA English DT Article ID SOLAR NEBULA; GAS; GRAINS; FLOWS; DUST AB Small but macroscopic particles-chondrules, higher temperature mineral inclusions, metal grains, and their like-dominate the fabric of primitive meteorites. The properties of these constituents, and their relationship to the fine dust grains which surround them, suggest that they led an extended existence in a gaseous protoplanetary nebula prior to their incorporation into their parent primitive bodies. In this paper we explore in some detail the velocities acquired by such particles in a turbulent nebula. We treat velocities in inertial space (relevant to diffusion), velocities relative to the gas and entrained microscopic dust (relevant to accretion of dust rims), and velocities relative to each other (relevant to collisions). We extend previous work by presenting explicit, closed-form solutions for the magnitude and size dependence of these velocities in this important particle size regime, and we compare these expressions with new numerical calculations. The magnitude and size dependence of these velocities have immediate applications to chondrule and CAI rimming by fine dust and to their diffusion in the nebula, which we explore separately. (C) 2003 Elsevier Inc. All rights reserved. C1 NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA. Bay Area Environm Res Inc, Sonoma, CA 94576 USA. RP Cuzzi, JN (reprint author), NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA. EM cuzzi@cosmic.arc.nasa.gov NR 34 TC 51 Z9 51 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 EI 1090-2643 J9 ICARUS JI Icarus PD JUL PY 2003 VL 164 IS 1 BP 127 EP 138 DI 10.1016/S0019-1035(03)00104-0 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 705AT UT WOS:000184374600009 ER PT J AU Jones, KB Head, JW Pappalardo, RT Moore, JM AF Jones, KB Head, JW Pappalardo, RT Moore, JM TI Morphology and origin of palimpsests on Ganymede based on Galileo observations SO ICARUS LA English DT Article DE Ganymede; Europa; impact processes; cratering ID EJECTA EMPLACEMENT; IMPACT FEATURES; EUROPA; CRATERS; SATELLITES; TOPOGRAPHY; CALLISTO; MISSION; JUPITER; TYRE AB Palimpsests are large, circular, low-relief impact scars on Ganymede and Callisto. These structures were poorly understood based on Voyager-era analysis, but high-resolution Galileo images allow more detailed inspection. We analyze images of four Ganymedean palimpsests targeted by Galileo: Memphis and Buto Faculae, Epigeus, and Zakar. Ganymedean craters and Europan ring structures are used as tools to help better understand palimpsests, based on morphologic similarities. From analysis of Galileo images, palimpsests consist of four surface units: central plains, an unoriented massif facies, a concentric massif facies, and outer deposits. Using as a tie point the location in these structures where secondary craters begin to appear, outer deposits of palimpsests are analogous to the outer ejecta facies of craters; the concentric massif facies of palimpsests are analogous to the pedestal facies of craters; and the unoriented massif facies and central plains are analogous to crater interiors. These analogies are supported by the presence of buried preexisting structure beneath the outer two and absence of buried structure beneath the inner two units. Our observations indicate that palimpsest deposits represent fluidized impact ejecta, rather than cryovolcanic deposits or ancient crater interiors. (C) 2003 Elsevier Inc. All rights reserved. C1 Brown Univ, Dept Geol Sci, Providence, RI 02912 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Jones, KB (reprint author), Univ Arizona, Dept Geosci, Gould Simpson Bldg,1040 E 4th St, Tucson, AZ 85721 USA. RI Jones, Kevin/A-7449-2014 OI Jones, Kevin/0000-0002-6386-2623 NR 28 TC 5 Z9 5 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 JUL PY 2003 VL 164 IS 1 BP 197 EP 212 DI 10.1016/S0019-1035(03)00128-3 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 705AT UT WOS:000184374600015 ER PT J AU Burgdorf, M Orton, GS Davis, GR Sidher, SD Feuchtgruber, H Griffin, MJ Swinyard, BM AF Burgdorf, M Orton, GS Davis, GR Sidher, SD Feuchtgruber, H Griffin, MJ Swinyard, BM TI Neptune's far-infrared spectrum from the ISO long-wavelength and short-wavelength spectrometers SO ICARUS LA English DT Article DE infrared observations; Neptune; abundances; atmospheres; spectrophotometry ID ROTOTRANSLATIONAL ABSORPTION-SPECTRA; HELIUM ABUNDANCE; VOYAGER MEASUREMENTS; OUTER PLANETS; URANUS; ATMOSPHERE; PERFORMANCE; SATURN; LWS; SUBMILLIMETER AB Neptune was observed by the Infrared Space Observatory (ISO) Long-Wavelength Spectrometer (LWS) between 46 and 185 mum. At wavelengths between 50 and 110 mum the accuracy of these measurements is less than or equal to 0.3 K. Observations of this planet made by the ISO Short-Wavelength Spectrometer between 28 and 44 mum were combined with the LWS data to determine a disk-averaged temperature profile and derive several physical quantities. The combined spectra are matched best by a He/(H-2 + He) mass ratio of 26.4(-3.5)(+2.6)%, reflecting a He molar fraction of 14.9(-2.2)(+1.7)%, assuming the molar fraction of CH4 to be 2% in the troposphere. This He abundance is consistent with one derived from analysis of joint Voyager-2 IRIS and radio occultation experiment data, a technique whose accuracy has recently been called into question. For a disk average, the para-H-2 fraction is found to be no more than similar to 1.5% different from its equilibrium value, and the N-2 mixing ratio is probably less than 0.7%. The composite spectrum is best fit by invoking a CH4 ice condensate cloud. Using a Mie approximation to particle scattering and absorption, best-fit particle sizes lie between 15 and 40 mum. The composite spectra are relatively insensitive to the vertical distribution of the cloud, but the particle scale height must be greater than 5% of the gas scale height. The best models are consistent with an effective temperature for Neptune that is 59.5 +/- 10.6 K, a value slightly lower than derived by the Voyager IRIS experiment-possibly Neptune's mid- and far-infrared emission has changed during the seven years that lie between its encounter with Voyager 2 and the first spectra taken of this planet with ISO. The model spectra are also ostensibly lower than ground-based observations in the spectral range of 17-24 mum, but this discrepancy can be relieved by perturbing the temperature of the lower stratosphere where the LWS spectrum is not particularly sensitive, combined with the uncertainty in the absolute calibration of the ground-based measurements. (C) 2003 Elsevier Inc. All rights reserved. C1 CALTECH, SIRTF Sci Ctr, Pasadena, CA 91125 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Joint Astron Ctr, Hilo, HI 96720 USA. Rutherford Appleton Lab, Didcot OX11 0QX, Oxon, England. Max Planck Inst Extraterr Phys, D-85748 Garching, Germany. Univ Wales Coll Cardiff, Dept Phys & Astron, Cardiff CF24 3YB, S Glam, Wales. RP Burgdorf, M (reprint author), CALTECH, SIRTF Sci Ctr, 220-6, Pasadena, CA 91125 USA. NR 45 TC 21 Z9 21 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 JUL PY 2003 VL 164 IS 1 BP 244 EP 253 DI 10.1016/S0019-1035(03)00138-6 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 705AT UT WOS:000184374600018 ER PT J AU Neto, A Maci, S AF Neto, A Maci, S TI Green's function for an infinite slot printed between two homogeneous dielectrics - Part 1: Magnetic currents SO IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION LA English DT Article DE Green's function; leaky wave antennas; slot antennas; slot lines ID STRIPLINE STRUCTURES; CHARACTERISTIC MODES; CONDUCTING PLANE; LEAKY MODES; EXCITATION; ANTENNAS; WAVE AB This sequence of papers presents an analytical closed form for the Green's function of an infinite slot printed between two different homogeneous dielectrics. This first part is devoted to the derivation of the slot magnetic current and to the discussion of the relevant physical implications. The Fourier spectrum of the magnetic current is derived by solving in analytical form, under small width approximation, the integral equation (IE) representing the continuity of the magnetic field trough the slot axis. The accuracy of the result is validated trough a fine meshing Method of Moments. From the consequent spectral expression, a closed form approximation of the leaky-wave propagation and attenuation constants is derived. An asymptotic expression for the current is also obtained by steepest descent path evaluation of the pertinent spectral integral. Analytical expressions of the quasi static (reactive) contribution is given for both elementary dipole and delta gap excitations. The asymptotic, uniform closed form approximation for the field in every space point will be formulated and discussed in the second part of the paper. C1 CALTECH, Jet Prop Lab, Sub MM Wave Adv Technol Grp, Pasadena, CA 91109 USA. Univ Siena, Dept Informat Engn, I-53100 Siena, Italy. RP Neto, A (reprint author), TNO, FEL, NL-2597 AK The Hague, Netherlands. NR 18 TC 36 Z9 36 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 0018-926X J9 IEEE T ANTENN PROPAG JI IEEE Trans. Antennas Propag. PD JUL PY 2003 VL 51 IS 7 BP 1572 EP 1581 DI 10.1109/TAP.2003.813625 PG 10 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA 699ZU UT WOS:000184088800014 ER PT J AU Neto, A De Maagt, P Maci, S AF Neto, A De Maagt, P Maci, S TI Optimized basis functions for slot antennas excited by coplanar waveguides SO IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION LA English DT Article DE coplanar waveguides; entire domain basis functions; method of moments; slot antennas; submillimeter wave antennas ID INTEGRATED LENS ANTENNAS; INTERNAL REFLECTIONS; RADIATION PROPERTIES; STRIPLINE STRUCTURES; INPUT IMPEDANCE; LEAKY MODES; EXCITATION AB A method is proposed for the analysis of slot antennas excited by coplanar waveguides. First, a standard integral equation for the continuity of the magnetic field is formulated. Then the appropriate equivalent magnetic currents of the method of moments are represented in terms of entire-domain basis functions which synthesize the resonant behavior of the slot and the field in proximity of the feeding source and of the bends. In order to define these basis functions, canonical geometries are identified, whose Green's functions have been found analytically. The accuracy and the effectiveness of the method in terms of convergence rate and number of unknowns is demonstrated by comparison with a standard fine meshing full-wave analysis. C1 CALTECH, Jet Prop Lab, Submm Wave Adv Technol Grp, Pasadena, CA 91109 USA. European Space Technol Ctr, Electromagnet Div, NL-2200 AG Noordwijk, Netherlands. Univ Siena, Dept Informat Engn, I-53100 Siena, Italy. RP Neto, A (reprint author), FNO, FEL, NL-2597 AK The Hague, Netherlands. NR 18 TC 14 Z9 14 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 0018-926X J9 IEEE T ANTENN PROPAG JI IEEE Trans. Antennas Propag. PD JUL PY 2003 VL 51 IS 7 BP 1638 EP 1646 DI 10.1109/TAP.2003.813636 PG 9 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA 699ZU UT WOS:000184088800022 ER PT J AU Moreels, P Snirekar, SE AF Moreels, P Snirekar, SE TI Watershed identification of polygonal patterns in noisy SAR images SO IEEE TRANSACTIONS ON IMAGE PROCESSING LA English DT Article DE edge dynamics; image segmentation; SAR images; speckle noise; watershed transform ID SEGMENTATION; DETECTOR; FILTERS AB This paper describes a new approach to pattern recognition in Synthetic Aperture Radar (SAR) images. A visual analysis of the images provided by NASA's Magellan mission to Venus has revealed a number of zones showing polygonal-shaped faults on the surface of the planet. The goal of this paper is to provide a method to automate the identification of such zones. The high level of noise in SAR images and its multiplicative nature make automated image analysis difficult and conventional edge detectors like those based on gradient images, inefficient. We present a scheme based on an improved watershed algorithm and a two-scale analysis. The method described extracts potential edges in the SAR image, analyzes the patterns obtained, and decides whether or not the image contains a "polygon area." This scheme can also be applied to other SAR or visual images, for instance in observation of Mars and Jupiter's satellite Europa. EDICS category: 2-SEGM (Segmentation). C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. CALTECH, NASA, Jet Propuls Lab, Pasadena, CA 91109 USA. RP Moreels, P (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 25 TC 14 Z9 14 U1 0 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 1057-7149 J9 IEEE T IMAGE PROCESS JI IEEE Trans. Image Process. PD JUL PY 2003 VL 12 IS 7 BP 740 EP 750 DI 10.1109/TIP.2003.814254 PG 11 WC Computer Science, Artificial Intelligence; Engineering, Electrical & Electronic SC Computer Science; Engineering GA 702EH UT WOS:000184206100002 PM 18237949 ER PT J AU Kenny, BH Lorenz, RD AF Kenny, BH Lorenz, RD TI Stator- and rotor-flux-based deadbeat direct torque control of induction machines SO IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS LA English DT Article; Proceedings Paper CT Annual Meeting of the Industry-Applications-Society CY SEP 30-OCT 05, 2001 CL CHICAGO, IL SP Ind Applicat Soc DE deadbeat control; direct torque control (DTC); induction motor; position-sensorless control ID AC MACHINES; VELOCITY; POSITION AB A new deadbeat type of direct torque control (DTC) is proposed, analyzed, and experimentally verified in this paper. The control is based on stator and rotor flux as state variables. This choice of state variables allows. a graphical representation which, is transparent and insightful. The graphical solution shows the effects of realistic considerations such as voltage and current limits. A position- and speed-sensorless implementation of,the control, based on the self-sensing signal injection technique, is also demonstrated experimentally for low-speed operation. The paper first develops the new deadbeat DTC methodology and graphical representation of the new. algorithm. It then evaluates feasibility via simulation and experimentally demonstrates performance of the new method with a laboratory prototype including the sensorless methods. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. Univ Wisconsin, Dept Mech Engn, Madison, WI 53706 USA. Univ Wisconsin, Dept Elect & Comp Engn, Madison, WI 53706 USA. RP Kenny, BH (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. EM Barbara.Kenny@grc.nasa.gov; lorenz@engr.wisc.edu NR 16 TC 77 Z9 80 U1 3 U2 11 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 0093-9994 J9 IEEE T IND APPL JI IEEE Trans. Ind. Appl. PD JUL-AUG PY 2003 VL 39 IS 4 BP 1093 EP 1101 DI 10.1109/TIA.2003.813727 PG 9 WC Engineering, Multidisciplinary; Engineering, Electrical & Electronic SC Engineering GA 704ZB UT WOS:000184370900023 ER PT J AU Brandon, EJ Wesseling, E White, V Ramsey, C Del Castillo, L Lieneweg, U AF Brandon, EJ Wesseling, E White, V Ramsey, C Del Castillo, L Lieneweg, U TI Fabrication and characterization of microinductors for distributed power converters SO IEEE TRANSACTIONS ON MAGNETICS LA English DT Article DE distributed power electronics; integrated passive components; microinductors ID MAGNETIC RECORDING-HEADS; INDUCTORS; DESIGN AB Inductors play a key role in dc-dc converters, but few options exist for implementing on-chip inductors for highly miniaturized, monolithic power converters. Microinductors constructed by standard microelectronic fabrication techniques with magnetic films as the core material have been investigated during the past 20 years with mixed results. A 13-mm(2) microinductor based on a spiral geometry and having L = 3.2 muH and Q = 1.3 at 1 MHz is reported here. Key issues regarding microinductor design and performance are discussed. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Brandon, EJ (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 26 TC 32 Z9 33 U1 0 U2 9 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 0018-9464 J9 IEEE T MAGN JI IEEE Trans. Magn. PD JUL PY 2003 VL 39 IS 4 BP 2049 EP 2056 DI 10.1109/TMAG.2003.812705 PN 2 PG 8 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA 703YA UT WOS:000184309300012 ER PT J AU Youngquist, RC Immer, C Lane, JE Simpson, JC AF Youngquist, RC Immer, C Lane, JE Simpson, JC TI Dynamics of a finite liquid oxygen column in a pulsed magnetic field SO IEEE TRANSACTIONS ON MAGNETICS LA English DT Article DE axially symmetric solenoid; liquid oxygen (LOX); magnetic force; paramagnetic fluids AB Current technology for pumping liquid oxygen (LOX)-the corrosive, highly explosive, cryogenic fluid used as the oxidizing agent in many space launch vehicles-involves traditional mechanisms such as impellers and rotors. The moving parts that are in contact with the fluid, as well as the seals around the pump, are potential failure points. These parts require special attention to protect against a reaction with LOX. We have developed a method to use pulsed magnetic fields to pump finite quantities of LOX that requires no moving parts in contact with the fluid. The equipment for this pumping technology is potentially nonintrusive and may be lighter in weight than existing mechanical pumps. Here, we compute equations of motion using a finite-difference technique, predicting the movement of a finite-length column of LOX in response to a pulsed magnetic field. We compare the calculated dynamics to experiment for various configurations. C1 NASA, Kennedy Space Ctr, FL 32899 USA. Dynacs Inc, Kennedy Space Ctr, FL 32899 USA. RP Youngquist, RC (reprint author), NASA, YA-C3, Kennedy Space Ctr, FL 32899 USA. NR 12 TC 8 Z9 8 U1 0 U2 3 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 0018-9464 J9 IEEE T MAGN JI IEEE Trans. Magn. PD JUL PY 2003 VL 39 IS 4 BP 2068 EP 2073 DI 10.1109/TMAG.2003.812722 PN 2 PG 6 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA 703YA UT WOS:000184309300015 ER PT J AU Simon, MK Alouini, MS AF Simon, MK Alouini, MS TI Some new results for integrals involving the generalized Marcum Q function and their application to performance evaluation over fading channels SO IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS LA English DT Article DE digital communication; fading channels; Marcum Q factor; probability of error ID SYMBOL DIFFERENTIAL DETECTION; DIVERSITY RECEPTION AB This letter evaluates some new integrals whose integrand involves the generalized Marcum Q function, both of whose arguments are linear functions of the integration variable. The resulting closed-form expressions obtained for these integrals are then applied to the error probability evaluation of noncoherent and differentiatly coherent detection with postdetection equal gain combining over Rayleigh and Nakagami fading channels. C1 Jet Prop Lab, Pasadena, CA 91109 USA. Univ Minnesota, Dept Elect Engn, Minneapolis, MN 55455 USA. RP Simon, MK (reprint author), Jet Prop Lab, Pasadena, CA 91109 USA. NR 18 TC 32 Z9 32 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 1536-1276 J9 IEEE T WIREL COMMUN JI IEEE Trans. Wirel. Commun. PD JUL PY 2003 VL 2 IS 4 BP 611 EP 615 DI 10.1109/TWC.2003.814344 PG 5 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA 702GC UT WOS:000184215300002 ER PT J AU Chiani, M Dardari, D Simon, MK AF Chiani, M Dardari, D Simon, MK TI New exponential bounds and approximations for the computation of error probability in fading channels SO IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS LA English DT Article DE bounds fading; M-ary differential phase-shift keying (MDPSK); M-ary phase-shift keying (MPSK); Q function; space-time codes (STCs) ID SPACE-TIME CODES; PHASE; NOISE AB We present new exponential bounds for the Gaussian Q function (one- and two-dimensional) and its inverse, and for M-ary phase-shift-keying (MPSK), M-ary differential phase-shift-keying (MDPSK) error probabilities over. additive white Gaussian noise channels. More precisely, the new bounds are in the form of the sum of exponential functions that, in the limit, approach the exact value. Then, a quite accurate and simple approximate expression given by the sum of two exponential functions is reported. The results are applied to the general problem of evaluating the average error probability in fading channels., Some examples of applications are also presented for the computation of the pairwise error probability of space-time codes and the average error probability of MPSK and MDPSK in fading channels. C1 Univ Bologna, DEIS, CNR, CSITE, I-40136 Bologna, Italy. Jet Prop Lab, Pasadena, CA 91109 USA. RP Chiani, M (reprint author), Univ Bologna, DEIS, CNR, CSITE, I-40136 Bologna, Italy. NR 19 TC 311 Z9 318 U1 0 U2 6 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 1536-1276 J9 IEEE T WIREL COMMUN JI IEEE Trans. Wirel. Commun. PD JUL PY 2003 VL 2 IS 4 BP 840 EP 845 DI 10.1109/TWC.2003.814350 PG 6 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA 702GC UT WOS:000184215300023 ER PT J AU Landis, GA AF Landis, GA TI Astrobiology: the case for Venus SO JBIS-JOURNAL OF THE BRITISH INTERPLANETARY SOCIETY LA English DT Article DE astrobiology; Venus; atmospheric science AB A case is made that the planet Venus is of significant interest for the study of astrobiology. Inparticular, in the regions of the atmosphere roughly fifty kilometers above the mean surface, Venus exhibits the most Earthlike environment in the solar system. Four interesting questions concerning Venus are related to astrobiology: was there ever past life on Venus, in an era when the environment of Venus was more like that of present-day Earth? Can the study of the atmospheric evolution of Venus, and of atmospheric chemical precursors to biology, give insight into the origins and evolution of life? Is there present-day life in the atmosphere of Venus? And, finally, is Venus an environment suitable for future life, or an environment that can be made suitable for life in the future. C1 NASA, John Glenn Res Ctr, Cleveland, OH 44135 USA. RP Landis, GA (reprint author), NASA, John Glenn Res Ctr, Mailstop 302-1,21000 Brookpk Rd, Cleveland, OH 44135 USA. EM geoffrey.a.landis@nasa.gov NR 14 TC 5 Z9 6 U1 1 U2 7 PU BRITISH INTERPLANETARY SOC PI LONDON PA 27-29 S LAMBETH RD, LONDON SW8 1SZ, ENGLAND SN 0007-084X J9 JBIS-J BRIT INTERPLA JI JBIS-J. Br. Interplanet. Soc. PD JUL-AUG PY 2003 VL 56 IS 7-8 BP 250 EP 254 PG 5 WC Engineering, Aerospace; Astronomy & Astrophysics; Geosciences, Multidisciplinary SC Engineering; Astronomy & Astrophysics; Geology GA 761XN UT WOS:000187940900003 ER PT J AU Manvi, R Weisbin, C Zimmerman, W Rodriguez, G AF Manvi, R Weisbin, C Zimmerman, W Rodriguez, G TI Decision tree assessment of challenging technologies for mission to Europa SO JOURNAL OF AEROSPACE ENGINEERING LA English DT Article DE ice; NASA; exploration AB The intriguing possibility that conditions exist that could support the evolution of life, as we understand it, in the ice-covered oceans of Europa makes the exploration of that Jovian moon a significant priority in NASA's solar system explorations. There is a need, therefore, to develop and demonstrate technologies and scientific methodologies that could be used to explore these extreme subice realms with the goal of establishing whether or not some form of life has evolved. A NASA search-for-life mission to Europa would involve site reconnaissance, site selection, landing, deep drilling through ice, small autonomous submersibles traversing the purported sea under the ice, and in-situ life detection. Many advanced technologies not currently available would be required. Identification and rank ordering of enabling technologies in a portfolio that can be developed for a certain specified research and development budget is crucial for mission success. This paper describes the results of utilizing a decision tree methodology and an appropriate optimization process to formalize the technology investment strategy. C1 CALTECH, Jet Prop Lab, Engn Staff, Pasadena, CA 91109 USA. CALTECH, Jet Prop Lab, Strateg Syst Technol Program Off, Pasadena, CA 91109 USA. RP Manvi, R (reprint author), CALTECH, Jet Prop Lab, Engn Staff, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 6 TC 0 Z9 0 U1 0 U2 1 PU ASCE-AMER SOC CIVIL ENGINEERS PI RESTON PA 1801 ALEXANDER BELL DR, RESTON, VA 20191-4400 USA SN 0893-1321 J9 J AEROSPACE ENG JI J. Aerosp. Eng. PD JUL PY 2003 VL 16 IS 3 BP 121 EP 128 DI 10.1016/(ASCE)0893-1321(2003)16:3(121) PG 8 WC Engineering, Aerospace; Engineering, Civil SC Engineering GA 692JL UT WOS:000183657900004 ER PT J AU Frink, NT Bonhaus, DL Vatsa, VN Bauer, SXS Tinetti, AF AF Frink, NT Bonhaus, DL Vatsa, VN Bauer, SXS Tinetti, AF TI Boundary condition for simulation of flow over porous surfaces SO JOURNAL OF AIRCRAFT LA English DT Article; Proceedings Paper CT AIAA 19th Applied Aerodynamics Conference CY JUN 11-14, 2001 CL ANAHEIM, CALIFORNIA SP AIAA ID AIRFOILS AB A new boundary condition is presented for simulating the flow over passively porous surfaces. The model eliminates the need for construction of a grid within an underlying plenum, thereby simplifying the numerical modeling of passively porous flow control systems and reducing computation cost. Two structured-grid flow solvers, TLNS3D and CFL3D, and one unstructured solver, USM3Dns, are used to develop and evaluate the model. Results presented for the three codes on a slender forebody with circumferential porosity and on a wing with leading edge porosity demonstrate good agreement with experimental data and a remarkable ability to predict the aggregate aerodynamic effects of surface porosity with a simple boundary condition. C1 NASA, Langley Res Ctr, Configurat Aerodynam Branch Aerodynam Aerothermod, Hampton, VA 23681 USA. NCI Informat Syst, Hampton, VA 23681 USA. RP Frink, NT (reprint author), NASA, Langley Res Ctr, Configurat Aerodynam Branch Aerodynam Aerothermod, Hampton, VA 23681 USA. NR 33 TC 3 Z9 5 U1 2 U2 5 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 JUL-AUG PY 2003 VL 40 IS 4 BP 692 EP 698 DI 10.2514/2.3147 PG 7 WC Engineering, Aerospace SC Engineering GA 709RJ UT WOS:000184637900011 ER PT J AU Baum, BA Frey, RA Mace, GG Harkey, MK Yang, P AF Baum, BA Frey, RA Mace, GG Harkey, MK Yang, P TI Nighttime multilayered cloud detection using MODIS and ARM data SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID AIRBORNE SIMULATOR IMAGERY; GENERAL-CIRCULATION; OVERLAP STATISTICS; CIRRUS CLOUDS; LAYER OVERLAP; ECMWF MODEL; RADAR; SCATTERING; PROFILES; HEIGHTS AB This study reports on recent progress toward the discrimination between pixels containing multilayered clouds, specifically optically thin cirrus overlying lower-level water clouds, and those containing single-layered clouds in nighttime Moderate Resolution Imaging Spectroradiometer ( MODIS) data. Cloud heights are determined from analysis of the 15-mum CO2 band data (i.e., the CO2-slicing method). Cloud phase is inferred from the MODIS operational bispectral technique using the 8.5- and 11-mum IR bands. Clear-sky pixels are identified from application of the MODIS operational cloud-clearing algorithm. The primary assumption invoked is that over a relatively small spatial area, it is likely that two cloud layers exist with some areas that overlap in height. The multilayered cloud pixels are identified through a process of elimination, where pixels from single-layered upper and lower cloud layers are eliminated from the data samples. For two case studies ( 22 April 2001 and 28 March 2001), ground-based lidar and radar observations are provided by the Atmospheric Radiation Measurement ( ARM) Program's Southern Great Plains (SGP) Clouds and Radiation Test Bed ( CART) site in Oklahoma. The surface-based cloud observations provide independent information regarding the cloud layering and cloud height statistics in the time period surrounding the MODIS overpass. C1 NASA, Langley Res Ctr, Hampton, VA 23665 USA. Univ Wisconsin, Cooperat Inst Meteorol Satellite Studies, Madison, WI USA. Univ Utah, Salt Lake City, UT USA. Univ Wisconsin, Madison, WI USA. Texas A&M Univ, College Stn, TX USA. RP Baum, BA (reprint author), NASA, CIMSS, 1225 W Dayton St, Madison, WI 53706 USA. EM bryan.baum@ssec.wisc.edu RI Yang, Ping/B-4590-2011; Baum, Bryan/B-7670-2011 OI Baum, Bryan/0000-0002-7193-2767 NR 36 TC 27 Z9 28 U1 1 U2 2 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8763 J9 J APPL METEOROL JI J. Appl. Meteorol. PD JUL PY 2003 VL 42 IS 7 BP 905 EP 919 DI 10.1175/1520-0450(2003)042<0905:NMCDUM>2.0.CO;2 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 695AV UT WOS:000183809700003 ER PT J AU Ahn, C Ziemke, JR Chandra, S Bhartia, PK AF Ahn, C Ziemke, JR Chandra, S Bhartia, PK TI Derivation of tropospheric column ozone from the Earth Probe TOMS/GOES co-located data sets using the cloud slicing technique SO JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS LA English DT Article DE tropospheric ozone; cloud slicing; Earth Probe TOMS; GOES ID MAPPING SPECTROMETER; TOMS; STRATOSPHERE; ULTRAVIOLET; SCATTERING; REGIONS; SCALE AB A recently developed technique called cloud slicing used for deriving upper tropospheric ozone from the Nimbus 7 total ozone mapping spectrometer (TOMS) instrument combined with temperature-humidity and infrared radiometer (THIR) is not applicable to the Earth Probe TOMS (EP TOMS) because this satellite platform does not have an instrument to measure cloud-top temperatures. For continuing monitoring of tropospheric ozone between 200 and 500 hPa and testing the feasibility of this technique across spacecrafts, EP TOMS data are co-located in time and space with the Geostationary Operational Environmental Satellite (GOES)-8 infrared data for year 2001 and early 2002, covering most of North and South America (45degreesS-45degreesN and 120degreesW-30degreesW). Results show that the maximum column amounts for the mid-latitudinal sites of the northern hemisphere are found in the March-May season. For the mid-latitudinal sites in the southern hemisphere, the highest column amounts are found in the September-November season with overall seasonal variability smaller than that in the nor-them hemisphere. The tropical sites show weaker seasonal variability compared to higher latitudes. The derived results for selected sites are cross-validated qualitatively with the seasonality of ozonesonde observations and the results from THIR analyses over the 1979-1984 time period. These comparisons show a reasonably good agreement among THIR, ozonesonde observations, and cloud slicing-derived column ozone. Cloud slicing measurements from TOMS coincide with large-scale convection events, especially in regions of the tropospheric wind jets (around +/-30degrees latitude). In these cases they may not be representative of typical conditions in the atmosphere. Two new variant approaches, high-low cloud slicing and ozone profile derivation from cloud slicing are introduced to estimate column ozone amounts using the entire cloud information in the troposphere. A future satellite platform such as the earth observing system (EOS) Aura with the ozone monitoring instrument (OMI) can provide better statistics of derived ozone because of improved spatial resolution and improved measurements of cloud-top pressures. (C) 2003 Elsevier Ltd. All rights reserved. C1 NASA, Goddard Space Flight Ctr, Atmospher Chem & Dynam Branch, Greenbelt, MD 20771 USA. Sci Syst & Applicat Inc, Lanham, MD USA. Univ Maryland Baltimore Cty, GEST Ctr, Baltimore, MD USA. RP Ziemke, JR (reprint author), NASA, Goddard Space Flight Ctr, Atmospher Chem & Dynam Branch, Code 916, Greenbelt, MD 20771 USA. RI Bhartia, Pawan/A-4209-2016 OI Bhartia, Pawan/0000-0001-8307-9137 NR 22 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 JUL PY 2003 VL 65 IS 10 BP 1127 EP 1137 DI 10.1016/S1364-6826(03)00166-4 PG 11 WC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences SC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences GA 735QB UT WOS:000186125100007 ER PT J AU Mayr, HG Mengel, JG Drob, DP Porter, HS Chan, KL AF Mayr, HG Mengel, JG Drob, DP Porter, HS Chan, KL TI Intraseasonal oscillations in the middle atmosphere forced by gravity waves SO JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS LA English DT Article ID QUASI-BIENNIAL OSCILLATION; DOPPLER-SPREAD PARAMETERIZATION; GENERAL-CIRCULATION MODEL; EQUATORIAL OSCILLATIONS; SEMIANNUAL OSCILLATION; ZONAL WIND; MOMENTUM DEPOSITION; SPECTRAL MODEL; DIURNAL TIDES; KELVIN WAVE AB In our Numerical Spectral Model (NSM) that incorporates Hines' Doppler Spread Parameterization, small-scale gravity waves (GW) propagating in the east/west direction can generate the essential features of the observed equatorial oscillations in the zonal circulation and in particular the QBO extending from the stratosphere into the upper mesosphere. We report here that the NSM also produces in the zonally symmetric (wavenumber=0) meridional circulation intraseasonal oscillations on time scales of a few months. A distinct but variable meridional wind oscillation (MWO) is generated, which appears to be the counterpart to the quasi-biennial oscillation (QBO). With a vertical grid-point resolution of about 0.5 km, the NSM produces the MWO through momentum deposition of GWs propagating in the north/south direction. The resulting momentum source represents a non-linear function of the meridional winds that is of third (generally odd) order, and this enables the oscillation, as is the case for the zonal winds in the QBO. Since the meridional winds are relatively small compared to the zonal winds. however, the vertical scale-length for the MWO is much smaller, i.e., only about 10 km instead of 40 km for the QBO. Consistent with the associated increase of the viscous stress, the period of the MWO is then short compared with that of the QBO, i.e., only about 1-4 months. Measurements with the HRDI instrument on LIARS show evidence of the MWO with periods between 2 and 3 months (Huang and Reber, J. Geophys. Res. (2003)). Depending on the strength of the GW forcing, the computed amplitudes of the MWO are typically 5 m/s in the upper stratosphere and mesosphere, and the associated temperature amplitudes are about 3 K. These amplitudes may be observable with the instruments on the TIMED spacecraft. Extended computer simulations with the NSM in 2D and 3D reveal that the MWO is modulated by and in turn influences the QBO. (C) 2003 Elsevier Ltd. All rights reserved. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Sci Syst & Applicat Inc, Lanham, MD USA. USN, Res Lab, Washington, DC 20375 USA. Furman Univ, Greenville, SC 29613 USA. Hong Kong Univ Sci & Technol, Hong Kong, Hong Kong, Peoples R China. RP Mayr, HG (reprint author), NASA, Goddard Space Flight Ctr, Code 916,Mail Code 910-4, Greenbelt, MD 20771 USA. RI Drob, Douglas/G-4061-2014; OI Drob, Douglas/0000-0002-2045-7740; Chan, Kwing/0000-0002-6428-1812 NR 36 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 JUL-SEP PY 2003 VL 65 IS 11-13 BP 1187 EP 1203 DI 10.1016/j.jastp.2003.07.008 PG 17 WC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences SC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences GA 747NB UT WOS:000186809600003 ER PT J AU Xie, PP Janowiak, JE Arkin, PA Adler, R Gruber, A Ferraro, R Huffman, GJ Curtis, S AF Xie, PP Janowiak, JE Arkin, PA Adler, R Gruber, A Ferraro, R Huffman, GJ Curtis, S TI GPCP Pentad precipitation analyses: An experimental dataset based on gauge observations and satellite estimates SO JOURNAL OF CLIMATE LA English DT Article ID OUTGOING LONGWAVE RADIATION; GLOBAL LAND PRECIPITATION; ASIAN SUMMER MONSOON; INTERCOMPARISON PROJECT; CLIMATOLOGY PROJECT; MONTHLY RAINFALL; MODEL; OSCILLATION; MICROWAVE; REANALYSIS AB As part of the Global Precipitation Climatology Project (GPCP), analyses of pentad precipitation have been constructed on a 2.5degrees latitude-longitude grid over the globe for a 23-yr period from 1979 to 2001 by adjusting the pentad Climate Prediction Center (CPC) Merged Analysis of Precipitation (CMAP) against the monthly GPCP-merged analyses. This adjustment is essential because the precipitation magnitude in the pentad CMAP is not consistent with that in the monthly CMAP or monthly GPCP datasets primarily due to the differences in the input data sources and merging algorithms, causing problems in applications where joint use of the pentad and monthly datasets is necessary. First, pentad CMAP-merged analyses are created by merging several kinds of individual data sources including gauge-based analyses of pentad precipitation, and estimates inferred from satellite observations. The pentad CMAP dataset is then adjusted by the monthly GPCP-merged analyses so that the adjusted pentad analyses match the monthly GPCP in magnitude while the high-frequency components in the pentad CMAP are retained. The adjusted analyses, called the GPCP-merged analyses of pentad precipitation, are compared to several gauge-based datasets. The results show that the pentad GPCP analyses reproduced spatial distribution patterns of total precipitation and temporal variations of submonthly scales with relatively high quality especially over land. Simple applications of the 23-yr dataset demonstrate that it is useful in monitoring and diagnosing intraseasonal variability. The Pentad GPCP has been accepted by the GPCP as one of its official products and is being updated on a quasi-real-time basis. C1 Climate Predict Ctr, NCEP, NWS, NOAA, Camp Springs, MD 20746 USA. Off Global Programs, OAR, NOAA, Silver Spring, MD USA. NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. Off Res & Applicat, NESDIS, NOAA, Camp Springs, MD USA. Sci Syst & Applicat Inc, Lanham, MD USA. Univ Maryland, Joint Ctr Earth Syst Technol, Baltimore, MD 21201 USA. RP Xie, PP (reprint author), Climate Predict Ctr, NCEP, NWS, NOAA, 5200 Auth Rd,605, Camp Springs, MD 20746 USA. RI Arkin, Phillip/F-5808-2010; Curtis, Scott/C-1115-2013; Huffman, George/F-4494-2014; Ferraro, Ralph/F-5587-2010; OI Huffman, George/0000-0003-3858-8308; Ferraro, Ralph/0000-0002-8393-7135; Curtis, Scott/0000-0001-9065-8639 NR 47 TC 198 Z9 207 U1 1 U2 13 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 JUL 1 PY 2003 VL 16 IS 13 BP 2197 EP 2214 DI 10.1175/2769.1 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 695XU UT WOS:000183856300005 ER PT J AU Eskridge, RE Luers, JK Redder, CR AF Eskridge, RE Luers, JK Redder, CR TI Unexplained discontinuity in the US radiosonde temperature data. Part I: Troposphere SO JOURNAL OF CLIMATE LA English DT Article ID TIME-SERIES; VAISALA RADIOSONDES; VIZ AB Inhomogeneities in U. S. radiosonde data that used the VIZ and Vaisala RS80 cannot be explained by radiation errors, which can be removed by the heat balance models. WMO intercomparision data, modeling results, temperature time series, and 1200 minus 0000 UTC temperature differences are examined to show that there appears to be an error in the U. S. RS80/RSN93 temperature correction software. Radiosonde soundings taken at U. S. stations that launch Vaisala RS80 radiosondes, which are integrated within the National Weather Service (NWS) Microcomputer Automatic Radio-Theodolite (Micro-ART) system, should not be used in climate studies since there is a large systematic error of unknown origin in the temperature data. This paper is the first of two and is primarily concerned with the midtroposphere. The second paper discusses the large unexplained 0000 and 1200 UTC differences in the stratosphere. C1 Natl Climat Ctr, NOAA, Asheville, NC USA. Univ Dayton, Res Inst, Dayton, OH 45469 USA. NASA, Goddard Space Flight Ctr, Data Assimilat Off, Greenbelt, MD 20771 USA. RP Eskridge, RE (reprint author), 1776 Sweeten Creek Rd, Asheville, NC 28803 USA. NR 17 TC 10 Z9 11 U1 0 U2 0 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 JUL PY 2003 VL 16 IS 14 BP 2385 EP 2395 DI 10.1175/2762.1 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 700EU UT WOS:000184100300006 ER PT J AU Yang, FL Kumar, A Schlesinger, ME Wang, WQ AF Yang, FL Kumar, A Schlesinger, ME Wang, WQ TI Intensity of hydrological cycles in warmer climates SO JOURNAL OF CLIMATE LA English DT Article ID GREENHOUSE-GAS; TEMPERATURE; MODEL AB The fact that the surface and tropospheric temperatures increase with increasing CO2 has been well documented by numerical model simulations; however, less agreement is found for the changes in the intensity of precipitation and the hydrological cycle. Here, it is demonstrated that while both the radiative heating by increasing CO2 and the resulting higher sea surface temperatures contribute to warm the atmosphere, they act against each other in changing the hydrological cycle. As a consequence, in a warmer climate forced by increasing CO2 the intensity of the hydrological cycle can be either more or less intense depending upon the degree of surface warming. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Nalt Ctr Environm Predict, Climate Predict Ctr, Washington, DC USA. Univ Illinois, Dept Atmospher Sci, Urbana, IL 61801 USA. Natl Ctr Environm Predict, SAIC, Environm Modeling Ctr, Washington, DC USA. RP Yang, FL (reprint author), NASA, Goddard Space Flight Ctr, Code 913, Greenbelt, MD 20771 USA. RI Yang, Fanglin/A-1948-2013 NR 15 TC 69 Z9 69 U1 0 U2 7 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 JUL PY 2003 VL 16 IS 14 BP 2419 EP 2423 DI 10.1175/2779.1 PG 5 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 700EU UT WOS:000184100300009 ER PT J AU Palosz, W Grasza, K Durose, K Halliday, DP Boyall, NM Dudley, M Raghothamachar, B Cai, L AF Palosz, W Grasza, K Durose, K Halliday, DP Boyall, NM Dudley, M Raghothamachar, B Cai, L TI The effect of the wall contact and post-growth cool-down on defects in CdTe crystals grown by 'contactless' physical vapour transport SO JOURNAL OF CRYSTAL GROWTH LA English DT Article DE cool-down; defects; dislocation distribution; synchrotron white beam X-ray topography; B1; CdTe ID LOW-SUPERSATURATION NUCLEATION; ZINC TELLURIDE CRYSTALS; PHOTOLUMINESCENCE AB A series of cadmium telluride crystals grown by physical vapour transport without contact with the ampoule walls and cooled at different rates were characterized using synchrotron X-ray topography, photoluminescence, and chemical etching. Strain from sticking to silica glass and its effect on the dislocation density is shown. It was found that very fast cool-down (e.g. air or water quenching) increases dislocation density by at least one order of magnitude. None of the samples had random dislocation distributions, but coarse clumping of dislocations on the scale of more than 100 Pill was more prevalent in slowly cooled crystals. Photoluminescence revealed that slow cooling (e.g. 10degreesC/h) favoured the donor-acceptor luminescence involving complex A centres. This was diminished in fast-cooled material. an effect presumed to be due to dislocation gettering. Fast cooling also enhanced the formation of shallow acceptors. Implications for Bridgman growth of CdTe and the vapour growth of CdZnTe are discussed briefly. (C) 2003 Elsevier Science B.V. All rights reserved. C1 NASA, George C Marshall Space Flight Ctr, USRA, Space Sci Lab, Huntsville, AL 35812 USA. Univ Durham, Dept Phys, Durham DH1 3LE, England. SUNY Stony Brook, Dept Mat Sci & Engn, Stony Brook, NY 11794 USA. RP Palosz, W (reprint author), NASA, George C Marshall Space Flight Ctr, USRA, Space Sci Lab, SD47, Huntsville, AL 35812 USA. RI Raghothamachar, Balaji/B-1094-2008; Durose, Ken/E-2617-2013 NR 17 TC 8 Z9 8 U1 0 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-0248 J9 J CRYST GROWTH JI J. Cryst. Growth PD JUL PY 2003 VL 254 IS 3-4 BP 316 EP 328 DI 10.1016/S0022-0248(03)01183-7 PG 13 WC Crystallography; Materials Science, Multidisciplinary; Physics, Applied SC Crystallography; Materials Science; Physics GA 688ZX UT WOS:000183468100005 ER PT J AU Palosz, W Grasza, K Boyd, PR Cui, Y Wright, G Roy, UN Burger, A AF Palosz, W Grasza, K Boyd, PR Cui, Y Wright, G Roy, UN Burger, A TI Photoluminescence of CdTe crystals grown by physical-vapor transport SO JOURNAL OF ELECTRONIC MATERIALS LA English DT Article; Proceedings Paper CT Workshop on Physics and Chemistry of II-VI Materials CY NOV 13-15, 2002 CL SAN DIEGO, CALIFORNIA SP USA, CECOM Night Vis & Elect Sensors Directorate, USA, Res Lab, USA, SMDC, USN, Electro Opt Ctr, Penn State Appl Res Lab, Off Naval Res, AF Res Lab, Miner, Mat & Mat Soc DE physical-vapor transport (PVT); photoluminescence (PL) spectra; CdTe : Al; CdTe : In; CdTe : Sc ID LOW-SUPERSATURATION NUCLEATION; OPTICAL-PROPERTIES; ACCEPTORS; DEFECTS; AG AB High-quality CdTe crystals with resistivities higher than 10(8) Omega cm were grown by the physical-vapor transport (PVT) technique. Indium, aluminum, and the transition-metal scandium were introduced at the nominal level of about 6 ppm to the source material. Low-temperature photoluminescence (PL) has been employed to identify the origins of PL emissions of the crystals. The emission peaks at 1.584 eV and 1.581 eV were found only in the In-doped crystal. The result suggests that the luminescence line at 1.584 eV is associated with Cd-vacancy/In complex. The intensity of the broadband centered at 1.43 eV decreases strongly with introduction of Sc. C1 NASA, George C Marshall Space Flight Ctr, Univ Space Res Assoc, Huntsville, AL 35812 USA. AM SRL, SE, EI, Adelphi, MD 20783 USA. IF PAS, Warsaw, Poland. Fisk Univ, Nashville, TN 37208 USA. RP Palosz, W (reprint author), NASA, George C Marshall Space Flight Ctr, Univ Space Res Assoc, SD46, Huntsville, AL 35812 USA. NR 25 TC 6 Z9 6 U1 0 U2 3 PU MINERALS METALS MATERIALS SOC PI WARRENDALE PA 184 THORN HILL RD, WARRENDALE, PA 15086 USA SN 0361-5235 J9 J ELECTRON MATER JI J. Electron. Mater. PD JUL PY 2003 VL 32 IS 7 BP 747 EP 751 DI 10.1007/s11664-003-0064-8 PG 5 WC Engineering, Electrical & Electronic; Materials Science, Multidisciplinary; Physics, Applied SC Engineering; Materials Science; Physics GA 703LW UT WOS:000184281700029 ER PT J AU Yang, SL Siow, YK Peschke, BD Tacina, RR AF Yang, SL Siow, YK Peschke, BD Tacina, RR TI Numerical study of nonreacting gas turbine combustor swirl flow using Reynolds stress model SO JOURNAL OF ENGINEERING FOR GAS TURBINES AND POWER-TRANSACTIONS OF THE ASME LA English DT Article ID 2ND-MOMENT CLOSURE; SIMULATION; TURBULENCE; SPRAY; JET AB This paper presents recent research on the use of a Reynolds stress turbulence model (RSTM) for three-dimensional flowfield simulation inside gas turbine combustors. It intends to show the motivations for using the RSTM in engine flow simulation, to present a further validation of the RSTM implementation in the KIVA code using the available experimental data, and to provide comparisons between RSTM and k-epsilon turbulence model results for chemically nonreacting swirling flows. The results show that, for high-degree swirl flow, the RSTM can provide predictions in favorable agreement with the experimental data, and that the RSTM predicts recirculations and high velocity gradients better than does the k-e turbulence model. The results also indicate that the choice of swirler has a significant influence on the structure of the combustor flowfield. C1 Michigan Technol Univ, Dept Mech Engn & Engn Mech, Houghton, MI 49931 USA. NASA, John H Glenn Res Ctr, Combust Technol Branch, Cleveland, OH 44135 USA. RP Yang, SL (reprint author), Michigan Technol Univ, Dept Mech Engn & Engn Mech, 1400 Townsend Dr, Houghton, MI 49931 USA. NR 28 TC 14 Z9 17 U1 0 U2 1 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA THREE PARK AVE, NEW YORK, NY 10016-5990 USA SN 0742-4795 J9 J ENG GAS TURB POWER JI J. Eng. Gas. Turbines Power-Trans. ASME PD JUL PY 2003 VL 125 IS 3 BP 804 EP 811 DI 10.1115/1.1560706 PG 8 WC Engineering, Mechanical SC Engineering GA 719PZ UT WOS:000185213400026 ER PT J AU Zimmerman, C Dukeman, G Hanson, J AF Zimmerman, C Dukeman, G Hanson, J TI Automated method to compute orbital reentry trajectories with heating constraints SO JOURNAL OF GUIDANCE CONTROL AND DYNAMICS LA English DT Article; Proceedings Paper CT AIAA Guidance, Navigation, and Control Conference CY AUG 05-08, 2002 CL MONTEREY, CALIFORNIA SP AIAA ID GUIDANCE AB An algorithm is presented that is designed to compute reentry trajectories for unpowered lifting reusable launch vehicles. The algorithm uses self-contained trajectory simulation and root finding techniques to determine the appropriate control sequences for solving reentry problems. For orbital reentries, the solution process breaks the trajectory into two distinct parts. The first part begins where the deorbited vehicle first encounters substantial atmosphere and can exercise trajectory control through the manipulation of aerodynamic lift. This phase of the flight is governed by an analytical, constant heat-rate following, bank angle control law. The second and final part of the trajectory begins where heat-rate control is no longer desired. During this time trajectory control is used to meet terminal range and altitude targets and is governed by a linear bank angle control law. The planning algorithm determines the value of the individual trajectory control parameters that shape the reentry. The planned trajectory is then used by a profile following guidance algorithm during actual flight. Test results for a variety of orbital and suborbital missions are shown. C1 NASA, George C Marshall Space Flight Ctr, Guidance Navigat & Control Grp, Huntsville, AL 35812 USA. RP Zimmerman, C (reprint author), NASA, George C Marshall Space Flight Ctr, Guidance Navigat & Control Grp, Huntsville, AL 35812 USA. NR 12 TC 39 Z9 49 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 JUL-AUG PY 2003 VL 26 IS 4 BP 523 EP 529 DI 10.2514/2.5096 PG 7 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA 699ZA UT WOS:000184086500002 ER PT J AU Crassidis, JL Markley, FL AF Crassidis, JL Markley, FL TI Unscented filtering for spacecraft attitude estimation SO JOURNAL OF GUIDANCE CONTROL AND DYNAMICS LA English DT Article AB A new spacecraft attitude estimation approach based on the unscented filter is derived. For nonlinear systems the unscented filter uses a carefully selected set of sample points to map the probability distribution more accurately than the linearization of the standard extended Kalman filter, leading to faster convergence from inaccurate initial conditions in attitude estimation problems. The filter formulation is based on standard attitude-vector measurements using a gyro-based model for attitude propagation. The global attitude parameterization is given by a quaternion, whereas a generalized three-dimensional attitude representation is used to define the local attitude error. A multiplicative quaternion-error approach is derived from the local attitude error, which guarantees that quaternion normalization is maintained in the filter. Simulation results indicate that the unscented filter is more robust than the extended Kalman filter under realistic initial attitude-error conditions. C1 SUNY Buffalo, Dept Mech & Aerosp Engn, Amherst, NY 14260 USA. NASA, Goddard Space Flight Ctr, Guidance Navigat & Control Syst Engn Branch, Greenbelt, MD 20771 USA. RP Crassidis, JL (reprint author), SUNY Buffalo, Dept Mech & Aerosp Engn, Amherst, NY 14260 USA. NR 26 TC 261 Z9 329 U1 3 U2 34 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 JUL-AUG PY 2003 VL 26 IS 4 BP 536 EP 542 DI 10.2514/2.5102 PG 7 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA 699ZA UT WOS:000184086500004 ER PT J AU Broadwater, K Barker, DB Mead, PF Kolasinski, J Watkins, JR AF Broadwater, K Barker, DB Mead, PF Kolasinski, J Watkins, JR TI Strain evaluation of epoxy-cured fiber-optic connectors SO JOURNAL OF LIGHTWAVE TECHNOLOGY LA English DT Article DE epoxy adhesives; fiber Bragg gratings (FBGs); fiber connectors; fiber-optic sensors; strain analysis ID OPTICAL-FIBER; STRESSES; FERRULE; FORCE AB Optical fiber connectors are passive components used to link two fiber links or a fiber link to a photonic device. One widely used type of fiber connector, a design that uses a thermally cured-epoxy adhesive, has been evaluated via Bragg grating-based fiber strain sensors. Strain sensors were used to evaluate the strain incurred by the optical fiber as a result of installation and subsequent environmental testing. Preliminary mechanical modeling and a strain analysis using Bragg grating-based strain sensors are discussed. Since the strain sensors were not exposed to uniaxial loading, mechanical modeling was used to determine the optimum placement of the sensors and the expected response. Also discussed are ongoing studies to evaluate the viscoelastic behavior of the epoxy and its effect on the strain state of the connector assembly. C1 Cornell Univ, Johnson Sch Management, Ithaca, NY 14853 USA. Univ Maryland, College Pk, MD 20742 USA. Natl Acad Engn, Washington, DC 20418 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Broadwater, K (reprint author), Cornell Univ, Johnson Sch Management, Ithaca, NY 14853 USA. NR 32 TC 1 Z9 1 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 0733-8724 J9 J LIGHTWAVE TECHNOL JI J. Lightwave Technol. PD JUL PY 2003 VL 21 IS 7 BP 1668 EP 1675 DI 10.1109/JLT.2003.814384 PG 8 WC Engineering, Electrical & Electronic; Optics; Telecommunications SC Engineering; Optics; Telecommunications GA 709XL UT WOS:000184651800010 ER PT J AU Nickerson, CA Ott, CM Wilson, JW Ramamurthy, R LeBlanc, CL Bentrup, KHZ Hammond, T Pierson, DL AF Nickerson, CA Ott, CM Wilson, JW Ramamurthy, R LeBlanc, CL Bentrup, KHZ Hammond, T Pierson, DL TI Low-shear modeled microgravity: a global environmental regulatory signal affecting bacterial gene expression, physiology, and pathogenesis SO JOURNAL OF MICROBIOLOGICAL METHODS LA English DT Review DE bacteria; bioreactor; gene expression; low shear; modeled microgravity; optimized suspension culture; pathogenesis; physiology; rotating wall vessel ID ROTATING-WALL BIOREACTOR; MICROCIN B17 PRODUCTION; SIMULATED MICROGRAVITY; ESCHERICHIA-COLI; TYPHIMURIUM VIRULENCE; STRESS; CELLS; CULTURE; GROWTH; TISSUE AB Bacteria inhabit an impressive variety of ecological niches and must adapt constantly to changing environmental conditions. While numerous environmental signals have been examined for their effect on bacteria, the effects of mechanical forces such as shear stress and gravity have only been investigated to a limited extent. However, several important studies have demonstrated a key role for the environmental signals of low shear and/or microgravity in the regulation of bacterial gene expression, physiology and pathogenesis [Chem. Rec. 1 (2001) 333; Appl. Microbiol. Biotechnol. 54 (2000) 33; Appl. Environ. Microbiol. 63 (1997) 4090; J. Ind. Microbiol. 18 (1997) 22; Curr. Microbiol. 34(4) (1997) 199; Appl. Microbiol. Biotechnol. 56(3-4) (2001) 384; Infect Immun. 68(6) (2000) 3147; Cell 109(7) (2002) 913; Appl. Environ. Microbiol. 68(11) (2002) 5408; Proc. Natl. Acad. Sci. U. S. A. 99(21) (2002) 13807]. The response of bacteria to these environmental signals, which are similar to those encountered during prokaryotic life cycles, may provide insight into bacterial adaptations to physiologically relevant conditions. This review focuses on the current and potential future research trends aimed at understanding the effect of the mechanical forces of low shear and microgravity analogues on different bacterial parameters. In addition, this review also discusses the use of microgravity technology to generate physiologically relevant human tissue models for research in bacterial pathogenesis. (C) 2003 Elsevier Science B.V. All rights reserved. C1 Tulane Univ, Sch Med, Dept Microbiol & Immunol, Program Mol Pathogenesis & Immun, New Orleans, LA 70112 USA. NASA, Lyndon B Johnson Space Ctr, EASI, Wyle Labs, Houston, TX 77058 USA. Tulane Univ, Med Ctr, Nephrol Sect, New Orleans, LA 70112 USA. Vet Affairs Med Ctr, New Orleans, LA 70112 USA. NASA, Lyndon B Johnson Space Ctr, Habitabil & Environm Factors Off, Houston, TX 77058 USA. RP Nickerson, CA (reprint author), Tulane Univ, Sch Med, Dept Microbiol & Immunol, Program Mol Pathogenesis & Immun, SL 38,1430 Tulane Ave, New Orleans, LA 70112 USA. NR 52 TC 76 Z9 84 U1 1 U2 22 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0167-7012 J9 J MICROBIOL METH JI J. Microbiol. Methods PD JUL PY 2003 VL 54 IS 1 BP 1 EP 11 DI 10.1016/S0167-7012(03)00018-6 PG 11 WC Biochemical Research Methods; Microbiology SC Biochemistry & Molecular Biology; Microbiology GA 680UH UT WOS:000182996600001 PM 12732416 ER PT J AU Lettington, AH Dunn, D Attia, M Blankson, IM AF Lettington, AH Dunn, D Attia, M Blankson, IM TI Passive millimetre-wave imaging architectures SO JOURNAL OF OPTICS A-PURE AND APPLIED OPTICS LA English DT Article; Proceedings Paper CT Conference on the Applied Optics and Optoelectronics (Photon02) CY SEP 02-05, 2002 CL CARDIFF, WALES SP Inst Phys DE passive millimetre-wave imaging; PMMW; architectures; scanning; beam forming ID SCANNING ANTENNA; MIRROR AB This paper discusses various passive millimetre-wave imaging systems. It includes sources of radiation, atmospheric transmission and a brief summary of their various applications. This is followed by a review of methods for detecting millimetre-wave radiation. From a cost analysis it is shown that scanned systems are at present far more cost effective than focal plane array of receivers for high-performance systems. Then various types of imaging system available are considered with greater emphasis on recent developments and their methods of beam forming. It is concluded that at present, and for the foreseeable future, optical beam forming and beam steering are the most cost-effective solutions. Some general remarks are included as to how receivers are matched to their collection apertures, followed by a section on optical beam-forming components. The recent development of a lightweight, low-cost, high-performance reflective lens is included. It is then shown how this may be combined with mechanical scanning systems to form high-performance passive millimetre-wave imaging systems. C1 Univ Reading, Dept Phys, Reading RG6 6AF, Berks, England. Johnson C Smith Univ, Charlotte, NC 28216 USA. NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Lettington, AH (reprint author), Univ Reading, Dept Phys, Reading RG6 6AF, Berks, England. NR 16 TC 11 Z9 11 U1 6 U2 6 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 1464-4258 J9 J OPT A-PURE APPL OP JI J. Opt. A-Pure Appl. Opt. PD JUL PY 2003 VL 5 IS 4 BP S103 EP S110 AR PII S1464-4258(03)58538-5 DI 10.1088/1464-4258/5/4/363 PG 8 WC Optics SC Optics GA 708MT UT WOS:000184571900036 ER PT J AU Wang, RY Scharenbroich, L Hart, C Wold, B Mjolsness, E AF Wang, RY Scharenbroich, L Hart, C Wold, B Mjolsness, E TI Clustering analysis of microarray gene expression data by splitting algorithm SO JOURNAL OF PARALLEL AND DISTRIBUTED COMPUTING LA English DT Article ID PATTERNS; CLASSIFICATION; TUMOR AB A clustering method based on recursive bisection is introduced for analyzing microarray gene expression data. Either or both dimensions for the genes and the samples of a given microarray dataset can be classified in an unsupervised fashion. Alternatively, if certain prior knowledge of the genes or samples is available, a supervised version of the clustering analysis can also be carried out. Either approach may be used to generate a partial or complete binary hierarchy, the dendrogram, showing the underlying structure of the dataset. Compared to other existing clustering methods used for microarray data analysis (such as hierarchical and K-means), the method presented here has the advantage of much improved computational efficiency while retaining effective separation of data clusters under-a distance metric, a straightforward parallel implementation, and useful extraction and presentation of biological information. Clustering results of both synthesized and experimental microarray data are presented to demonstrate the performance of the algorithm. (C) 2003 Elsevier Inc. All rights reserved. C1 Harvey Mudd Coll, Dept Engn, Claremont, CA 91711 USA. Jet Prop Lab, Pasadena, CA 91109 USA. CALTECH, Pasadena, CA 91125 USA. Univ Calif Irvine, Sch Informat & Comp Sci, Inst Genom & Bioinformat, Irvine, CA 92697 USA. RP Wang, RY (reprint author), Harvey Mudd Coll, Dept Engn, Claremont, CA 91711 USA. NR 17 TC 5 Z9 5 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 0743-7315 J9 J PARALLEL DISTR COM JI J. Parallel Distrib. Comput. PD JUL-AUG PY 2003 VL 63 IS 7-8 BP 692 EP 706 DI 10.1016/S0743-7315(03)00085-6 PG 15 WC Computer Science, Theory & Methods SC Computer Science GA 728HQ UT WOS:000185712100004 ER PT J AU Park, C Bogdanoff, DW Mehta, UB AF Park, C Bogdanoff, DW Mehta, UB TI Theoretical performance of a magnetohydrodynamic-bypass scramjet engine with nonequilibrium ionization SO JOURNAL OF PROPULSION AND POWER LA English DT Article AB The theoretical performance of a scramjet propulsion system in which a magnetohydrodynamic (MHD) energy bypass scheme is operated in a nonequilibrium ionization environment is evaluated. In the MHD generator, the incoming airflow at a temperature too low to produce the required ionization is seeded with cesium and ionized by the use of an unspecified external power source. The resulting nonequilibrium environment is described using a two-temperature model. The accelerator is operated with equilibrium ionization. The expansion through the nozzle is-calculated with account taken of finite rate reactions, and the boundary layer is assumed to be fully turbulent. The results show that the required external power is of the same order of magnitude as that of the power generated in the MHD generator. An MHD energy bypass propulsion scheme looks to be more promising with the equilibrium ionization method than with the nonequilibrium ionization method. C1 ELORET Corp, Sunnyvale, CA 94087 USA. NASA, Ames Res Ctr, Space Technol Div, Moffett Field, CA 94035 USA. RP Park, C (reprint author), ELORET Corp, Sunnyvale, CA 94087 USA. NR 13 TC 3 Z9 5 U1 0 U2 2 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 JUL-AUG PY 2003 VL 19 IS 4 BP 529 EP 537 DI 10.2514/2.6156 PG 9 WC Engineering, Aerospace SC Engineering GA 701XC UT WOS:000184193400002 ER PT J AU Katz, I Anderson, JR Polk, JE Brophy, JR AF Katz, I Anderson, JR Polk, JE Brophy, JR TI One-dimensional hollow cathode model SO JOURNAL OF PROPULSION AND POWER LA English DT Article ID ELECTRON-IMPACT; CROSS-SECTIONS; IONIZATION; BARIUM; PLASMA AB Hollow cathodes with barium-rich inserts are used in ion engines as electron sources both in the discharge chamber and to neutralize the. ion beam. Future deep space missions will require hollow cathode lifetimes in excess of the 28,000 h demonstrated during the International Space Station plasma contactor hollow cathode life test. A hollow cathode model is developed based on the observation that xenon ion mobility is diffusion limited due to resonant charge exchange reactions. Application of the model to the orifice region shows that the resultant ion generation profile correlates with previously reported orifice erosion. Modeling of the insert region shows that vapor-phase barium atoms are ionized almost immediately and electric fields accelerate the ions upstream from the "emission zone". C1 CALTECH, Jet Prop Lab, Adv Propuls Technol Grp, Pasadena, CA 91109 USA. RP Katz, I (reprint author), CALTECH, Jet Prop Lab, Adv Propuls Technol Grp, MS 125-109,4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 19 TC 16 Z9 20 U1 0 U2 5 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 JUL-AUG PY 2003 VL 19 IS 4 BP 595 EP 600 DI 10.2514/2.6146 PG 6 WC Engineering, Aerospace SC Engineering GA 701XC UT WOS:000184193400010 ER PT J AU Park, C Bogdanoff, D Mehta, UB AF Park, C Bogdanoff, D Mehta, UB TI Errata on theoretical performance of frictionless magnetohydrodynamics-bypass scramjet (vol 17, pg 591, 2001) SO JOURNAL OF PROPULSION AND POWER LA English DT Correction C1 Eloret Corp, Sunnyvale, CA 94087 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Park, C (reprint author), Eloret Corp, Sunnyvale, CA 94087 USA. NR 3 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 0748-4658 J9 J PROPUL POWER JI J. Propul. Power PD JUL-AUG PY 2003 VL 19 IS 4 BP 718 EP 719 DI 10.2514/2.6163 PG 2 WC Engineering, Aerospace SC Engineering GA 701XC UT WOS:000184193400026 ER PT J AU Sommer, AP McKay, DS Ciftcioglu, N Oron, U Mester, AR Kajander, EO AF Sommer, AP McKay, DS Ciftcioglu, N Oron, U Mester, AR Kajander, EO TI Living nanovesicles-chemical and physical survival strategies of primordial biosystems SO JOURNAL OF PROTEOME RESEARCH LA English DT Article DE nanobacteria; nannobacteria; nanovesicles; extremophiles; origin of life models ID MARTIAN METEORITE ALH84001; KIDNEY-STONE FORMATION; LASER IRRADIATION; IN-VITRO; NANOBACTERIA; LIGHT; LIFE; CELLS; MINERALIZATION AB Life on Earth and Mars could have started with self-assembled nanovesicles similar to the present nanobacteria (NB). To resist extreme environmental stress situations and periods of nutritional deprivation, nanovesicles would have had a chemical composition protected by a closed mineralized compartment, facilitating their development in a primordial soup, or other early wet environment. Their survivability would have been enhanced if they had mechanisms for metabolic communication, and an ability to collect primordially available energy forms. Here, we establish an irreducible model system for life formation starting with NB. C1 Univ Ulm, Cent Inst Biomed Engn, D-89081 Ulm, Germany. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. NASA, Lyndon B Johnson Space Ctr, Univ Space Res Assoc, Houston, TX 77058 USA. Tel Aviv Univ, Dept Zool, Fac Life Sci, IL-69978 Tel Aviv, Israel. Semmelweis Univ, Dept Radiol & Oncotherapy, H-1082 Budapest, Hungary. Univ Kuopio, Dept Biochem, FIN-70211 Kuopio, Finland. RP Sommer, AP (reprint author), Univ Ulm, Cent Inst Biomed Engn, D-89081 Ulm, Germany. EM samoan@gmx.net NR 28 TC 29 Z9 30 U1 0 U2 6 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1535-3893 J9 J PROTEOME RES JI J. Proteome Res. PD JUL-AUG PY 2003 VL 2 IS 4 BP 441 EP 443 DI 10.1021/pr034005h PG 3 WC Biochemical Research Methods SC Biochemistry & Molecular Biology GA 711WR UT WOS:000184764500012 PM 12938934 ER PT J AU Fang, HF Lou, M Yang, BG Yang, YB AF Fang, HF Lou, M Yang, BG Yang, YB TI Modeling of gossamer space structures with distributed transfer function method SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article; Proceedings Paper CT AIAA/ASME/ASCE/AHS/ASC 43rd Structures, Structural Dynamics, and Materials Conference CY APR 22-25, 2002 CL DENVER, COLORADO SP AIAA, ASME, ASCE, AHS, ASC AB A new structural modeling and analysis method, the distributed transfer function method, is presented for application to gossamer space structures. The distributed transfer function method uses distributed transfer functions, instead of shape function used by traditional finite element solvers, to represent the displacement field. The distributed transfer function method maintains the modeling flexibility of the finite element method, so that it is capable of modeling multibody, complex structures, but it requires much fewer nodes and results in a significant reduction of computational time. The distributed transfer functions give rise to closed-form analytical solutions of both displacement and strain fields. As a result, the distributed transfer function method only decomposes a structure at those points where multiple components are connected, to keep each component as large as possible. Gossamer space structures are generally composed of several long booms and large membranes.. Therefore, the distributed transfer function method can be used to model a gossamer structure with a small number of unknowns and matrices of low order. It offers very accurate results with high computational efficiency. The distributed transfer function method is applied to investigate the sensitivity of buckling strength of an inflatable/rigidizable boom to the variations in bending stiffness. C1 CALTECH, Jet Prop Lab, Mech Syst Engn & Res Div, Pasadena, CA 91109 USA. Univ So Calif, Dept Aerosp & Mech Engn, Los Angeles, CA 90089 USA. RP Fang, HF (reprint author), CALTECH, Jet Prop Lab, Mech Syst Engn & Res Div, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 7 TC 1 Z9 1 U1 2 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 JUL-AUG PY 2003 VL 40 IS 4 BP 548 EP 552 DI 10.2514/2.3976 PG 5 WC Engineering, Aerospace SC Engineering GA 711XB UT WOS:000184765400011 ER PT J AU Dunlap, PH Steinetz, BM Curry, DM DeMange, JJ Rivers, HK Hsu, SY AF Dunlap, PH Steinetz, BM Curry, DM DeMange, JJ Rivers, HK Hsu, SY TI Investigations of a control surface seal for Reentry vehicles SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article; Proceedings Paper CT AIAA/ASME/ASCE/AHS/ASC 43rd Structures, Structural Dynamics, and Materials Conference CY APR 22-25, 2002 CL DENVER, COLORADO SP AIAA, ASME, ASCE, AHS, ASC AB Reentry vehicles generally require control surfaces such as rudders and body flaps to steer them during flight. Control surface seals are installed along hinge lines and where control surface edges move close to the vehicle body. These seals must operate at high temperatures and limit heat transfer to underlying structures to prevent overheating and possible loss of vehicle structural integrity. Test results are presented for the baseline rudder/fin seal design for the X-38 reentry vehicle. Compressing seals at the predicted peak seal temperature of 1900degreesF resulted in loss of seal resiliency. The vertical Inconel rudder/fin rub. surface was redesigned to account for this loss of resiliency. Room-temperature compression tests revealed that seal unit loads and contact pressures were below limits set to protect shuttle thermal tiles on the horizontal sealing surface. The seals survived an ambienttemperature 1000 cycle scrub test over sanded shuttle tiles and were able to disengage and reengage the tile edges during testing. Arcjet tests on a single seal caused a large temperature drop (DeltaT= 1710degreesF) in the seal gap and confirmed the need for seals in the rudder/fin gap location. These test results verified that this seal is satisfactory. for the X-38 application. C1 NASA, John H Glenn Res Ctr Lewis Field, Mech Components Branch, Cleveland, OH 44135 USA. NASA, Lyndon B Johnson Space Ctr, Thermal Branch, Houston, TX 77058 USA. Univ Toledo, Mech Components Branch, Toledo, OH 43606 USA. NASA, Langley Res Ctr, Met & Thermal Struct Branch, Hampton, VA 23681 USA. Lockheed Martin Space Operat, Met & Thermal Struct Branch, Hampton, VA USA. RP Dunlap, PH (reprint author), NASA, John H Glenn Res Ctr Lewis Field, Mech Components Branch, Cleveland, OH 44135 USA. NR 13 TC 3 Z9 5 U1 1 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 JUL-AUG PY 2003 VL 40 IS 4 BP 570 EP 583 DI 10.2514/2.3979 PG 14 WC Engineering, Aerospace SC Engineering GA 711XB UT WOS:000184765400014 ER PT J AU Heaton, AF Longuski, JM AF Heaton, AF Longuski, JM TI Feasibility of a Galileo-style tour of the Uranian satellites SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article ID AEROGRAVITY-ASSIST TRAJECTORIES; AUTOMATED DESIGN; MISSIONS; JUPITER; URANUS AB Gravity-assist trajectories have been a key to outer solar system exploration. In particular, the gravity-assist tour of the Jovian satellites has contributed significantly to the success of the Galileo mission. A comparison of the Jovian system to the Uranian system reveals that the two possess similar satellite/planet mass ratios. Tisserand graphs of the Uranian system also indicate the potential for tours at Uranus. In this paper we devise tour strategies and design a prototypical tour of the Uranian satellites, demonstrating that tours at Uranus are feasible. In an example tour that launches in 2008, a series of flybys with Titania are used to reduce the inclination (14 deg at arrival) to permit encounters with Oberon, Ariel, and Umbriel. The tour involves over 40 flybys and ends after two years with a hyberbolic excess velocity with respect to Ariel of 0.92 km/s, which permits insertion into orbit about Ariel. C1 George C Marshall Space Flight Ctr, Guidance Navigat & Controls Grp, Huntsville, AL 35812 USA. Purdue Univ, Sch Aeronaut & Astronaut, W Lafayette, IN 47907 USA. RP Heaton, AF (reprint author), George C Marshall Space Flight Ctr, Guidance Navigat & Controls Grp, Mail Stop TD54, Huntsville, AL 35812 USA. NR 26 TC 4 Z9 4 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 JUL-AUG PY 2003 VL 40 IS 4 BP 591 EP 596 DI 10.2514/2.3981 PG 6 WC Engineering, Aerospace SC Engineering GA 711XB UT WOS:000184765400016 ER PT J AU Parks, DE Katz, I AF Parks, DE Katz, I TI Asymptotic magnetic field expansion in mini-magnetospheric plasma propulsion SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article C1 Alameda Appl Sci Corp, Encinitas, CA 92024 USA. CALTECH, Jet Prop Lab, Adv Propuls Technol Grp, Pasadena, CA 91109 USA. RP Parks, DE (reprint author), Alameda Appl Sci Corp, 169 Saxony Rd,Suite 210, Encinitas, CA 92024 USA. NR 2 TC 2 Z9 2 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 JUL-AUG PY 2003 VL 40 IS 4 BP 597 EP 598 PG 2 WC Engineering, Aerospace SC Engineering GA 711XB UT WOS:000184765400017 ER PT J AU Prabhu, DK Marvin, JG Davies, CB Wright, MJ Venkatapathy, E Papadopoulos, PE Brown, JL AF Prabhu, DK Marvin, JG Davies, CB Wright, MJ Venkatapathy, E Papadopoulos, PE Brown, JL TI Comment on "X-33 computational aeroheating predictions and comparisons with experimental data" SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Editorial Material C1 ELORET, Sunnyvale, CA 94087 USA. NASA, Ames Res Ctr, Reacting Flow Environm Branch, Moffett Field, CA 94035 USA. RP Prabhu, DK (reprint author), ELORET, 690 W Fremont Ave,Suite 8, Sunnyvale, CA 94087 USA. NR 5 TC 0 Z9 0 U1 0 U2 0 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 JUL-AUG PY 2003 VL 40 IS 4 BP 601 EP 602 DI 10.2514/2.3984 PG 2 WC Engineering, Aerospace SC Engineering GA 711XB UT WOS:000184765400019 ER PT J AU Hollis, RR AF Hollis, RR TI Reply by the author to Prabhu et al. SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Editorial Material C1 NASA, Langley Res Ctr, Aerothermodynam Branch, Hampton, VA 23681 USA. RP Hollis, RR (reprint author), NASA, Langley Res Ctr, Aerothermodynam Branch, Hampton, VA 23681 USA. NR 3 TC 0 Z9 0 U1 0 U2 0 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 JUL-AUG PY 2003 VL 40 IS 4 BP 602 EP 603 PG 2 WC Engineering, Aerospace SC Engineering GA 711XB UT WOS:000184765400020 ER PT J AU Bhagwat, MJ Leishman, JG AF Bhagwat, MJ Leishman, JG TI Rotor aerodynamics during maneuvering flight using a time-accurate free-vortex wake SO JOURNAL OF THE AMERICAN HELICOPTER SOCIETY LA English DT Article ID HELICOPTER; MODEL; STABILITY AB A time-accurate free-vortex method was developed to predict the evolution of the rotor wake aerodynamics during transient, maneuvering flight conditions. Because of the highly non-linear nature of the rotor wake problem, the numerical algorithm was rigorously examined for stability, accuracy and convergence. Solution convergence was demonstrated with a verified second-order accuracy for both hovering and forward flight conditions. The wake model was then validated for transient conditions using measured rotor responses following rapid ramp increases in collective pitch, and also for oscillatory blade pitch inputs. The methodology was applied to study idealized maneuvering flight problems consisting of imposed angular pitch and roll rates. The results showed that time-dependent effects associated with maneuver-induced wake distortion significantly influenced the rotor aerodynamics and, also, the blade flapping response. The magnitude of the maneuver-induced wake distortion effects was found to vary with rotor operating state as well as with rotor geometric parameters such as the blade flapping frequency. The results also suggested that linearized inflow models using configuration and/or operating state independent wake distortion factors may not be adequate descriptors of the maneuver problem. C1 Univ Maryland, Glenn L Martin Inst Technol, Dept Aerosp Engn, College Pk, MD 20742 USA. RP Bhagwat, MJ (reprint author), NASA, Ames Res Ctr, ELORET COrp, M-S 215-1, Moffett Field, CA 94035 USA. NR 31 TC 8 Z9 13 U1 0 U2 3 PU AMER HELICOPTER SOC INC PI ALEXANDRIA PA 217 N WASHINGTON ST, ALEXANDRIA, VA 22314 USA SN 0002-8711 J9 J AM HELICOPTER SOC JI J. Am. Helicopter Soc. PD JUL PY 2003 VL 48 IS 3 BP 143 EP 158 PG 16 WC Engineering, Aerospace SC Engineering GA 702FH UT WOS:000184213700001 ER PT J AU Ruzicka, GC Hodges, DH AF Ruzicka, GC Hodges, DH TI A mixed finite-element treatment of rotor blade elongation SO JOURNAL OF THE AMERICAN HELICOPTER SOCIETY LA English DT Article; Proceedings Paper CT American-Helicopter-Society Aeromechanics Specialists Meeting CY NOV 13-14, 2000 CL ATLANTA, GEORGIA SP Amer Helicopter Soc ID EQUATIONS; DYNAMICS; BEAM AB The accuracy of rotor blade basis reduction hinges critically on how axial elongation is treated. This fact is illustrated by analyzing an articulated rotorcraft blade using several blade formulations, and comparing their basis reduction accuracies. It is shown that classical, displacement-based finite elements fail to accurately represent the blade's axial strain when the blade's basis is reduced because of ill conditioning caused by the near inextensibility of the blade. This problem may be solved by introducing the axial force, or a related quantity, as a variable in the analysis. The mixed finite-element method is the preferred approach for accomplishing this because it imposes no restrictions on the model's geometry, but it leads to additional degrees of freedom and does not explicitly account for the nonlinear axial foreshortening effect. It is shown how both of these shortcomings may be removed by using the mixed element force equations to eliminate axial displacement degress of freedom in favor of axial force and bending degrees of freedom. The elimination process is formulated first for a single element, and then for an arbitrary assemblage of elements. In essence, the procedure may be viewed as a generalization, to blades of arbitrary geometry, of the axial elongation variable, which is widely used by rotorcraft analysts. C1 NASA, Ames Res Ctr, Rotorcraft Div, Aeroflightdynam Directorate,AMRDEC, Moffett Field, CA 94035 USA. Georgia Inst Technol, Sch Aerosp Engn, Atlanta, GA 30332 USA. RP Ruzicka, GC (reprint author), NASA, Ames Res Ctr, Rotorcraft Div, Aeroflightdynam Directorate,AMRDEC, Moffett Field, CA 94035 USA. NR 19 TC 2 Z9 2 U1 0 U2 0 PU AMER HELICOPTER SOC INC PI ALEXANDRIA PA 217 N WASHINGTON ST, ALEXANDRIA, VA 22314 USA SN 0002-8711 J9 J AM HELICOPTER SOC JI J. Am. Helicopter Soc. PD JUL PY 2003 VL 48 IS 3 BP 167 EP 175 PG 9 WC Engineering, Aerospace SC Engineering GA 702FH UT WOS:000184213700003 ER PT J AU Quadrelli, MB AF Quadrelli, MB TI Dynamics and control of novel orbiting formations with internal dynamics SO JOURNAL OF THE ASTRONAUTICAL SCIENCES LA English DT Article AB This study analyzes for the first time the interaction between a rigid and a deformable vehicle in formation. In this paper we investigate the interaction between an orbiting system of two tethered spacecraft and a single separated spacecraft. This problem arises when a distributed sensor array formed by connected vehicles is being commanded to reconfigure from a remote location by another remote vehicle. In another example, a free-flying robotic inspector vehicle flies around a deployed large space structure, such as a tethered spacecraft, deployed membrane or solar reflector, with the intent of monitoring the structural integrity of the larger vehicle prior to docking and possibly servicing it. This paper points out that even if the additional internal dynamics of the system caused by flexibility is considered, high pointing precision can be achieved when a fictitious rigid frame is used to track the tethered system. Even higher precision can be achieved when one specific point on the deformable structure is directly tracked. The results show that accuracy to the sub centimeter level or less in relative positioning and to the arc second level in relative angle can also be achieved with this novel architecture. C1 CALTECH, Jet Prop Lab, Guidance & Control Anal Grp, Pasadena, CA 91109 USA. RP Quadrelli, MB (reprint author), CALTECH, Jet Prop Lab, Guidance & Control Anal Grp, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 8 TC 2 Z9 2 U1 0 U2 0 PU AMER ASTRONAUTICAL SOC PI SPRINGFIELD PA 6352 ROLLING MILL PLACE SUITE 102, SPRINGFIELD, VA 22152 USA SN 0021-9142 J9 J ASTRONAUT SCI JI J. Astronaut. Sci. PD JUL-SEP PY 2003 VL 51 IS 3 BP 319 EP 337 PG 19 WC Engineering, Aerospace SC Engineering GA 850FL UT WOS:000223596500006 ER PT J AU Quadrelli, MB AF Quadrelli, MB TI Effect of distributed rod and string flexibility on formation dynamic stability SO JOURNAL OF THE ASTRONAUTICAL SCIENCES LA English DT Article AB We study the effect of distributed elasticity on the dynamics of an orbiting formation. The paradigm considered in the paper, namely two bodies connected by one spring in formation with a separated free-flying body, represents a prototype system for a variety of possible problems. Conclusions are derived on the system's stability, as well as on the system performance under closed-loop control. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Quadrelli, MB (reprint author), CALTECH, Jet Prop Lab, Mail Stop 198-326, Pasadena, CA 91109 USA. NR 5 TC 1 Z9 1 U1 0 U2 0 PU AMER ASTRONAUTICAL SOC PI SPRINGFIELD PA 6352 ROLLING MILL PLACE SUITE 102, SPRINGFIELD, VA 22152 USA SN 0021-9142 J9 J ASTRONAUT SCI JI J. Astronaut. Sci. PD JUL-SEP PY 2003 VL 51 IS 3 BP 339 EP 357 PG 19 WC Engineering, Aerospace SC Engineering GA 850FL UT WOS:000223596500007 ER PT J AU Smith, GL Rutan, DA AF Smith, GL Rutan, DA TI The diurnal cycle of outgoing longwave radiation from earth radiation budget experiment measurements SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID EXPERIMENT ERBE; VARIABILITY; CLOUD; GCM AB The diurnal cycle of outgoing longwave radiation (OLR) from the earth is analyzed by decomposing satellite observations into a set of empirical orthogonal functions (EOFs). The observations are from the Earth Radiation Budget Experiment ( ERBE) scanning radiometer aboard the Earth Radiation Budget Satellite, which had a precessing orbit with 578 inclination. The diurnal cycles of land and ocean differ considerably. The first EOF for land accounts for 73% to 85% of the variance, whereas the first EOF for ocean accounts for only 16% to 20% of the variance, depending on season. The diurnal cycle for land is surprisingly symmetric about local noon for the first EOF, which is approximately a half-sine during day and flat at night. The second EOF describes lead - lag effects due to surface heating and cloud formation. For the ocean, the first EOF and second EOF are similar to that of land, except for spring, when the first ocean EOF is a semidiurnal cycle and the second ocean EOF is the half-sine. The first EOF for land has a daytime peak of about 50 W m(-2), whereas the first ocean EOF peaks at about 25 W m(-2). The geographical and seasonal patterns of OLR diurnal cycle provide insights into the interaction of radiation with the atmosphere and surface and are useful for validating and upgrading circulation models. C1 Virginia Polytech Inst & State Univ, Blacksburg, VA 24061 USA. Analyt Serv & Mat Inc, Hampton, VA 23666 USA. RP Smith, GL (reprint author), NASA, Langley Res Ctr, Mail Stop 420, Hampton, VA 23681 USA. NR 23 TC 23 Z9 23 U1 0 U2 6 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 JUL PY 2003 VL 60 IS 13 BP 1529 EP 1542 DI 10.1175/2997.1 PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 685UD UT WOS:000183280900001 ER PT J AU Beutter, BR Eckstein, MP Stone, LS AF Beutter, BR Eckstein, MP Stone, LS TI Saccadic and perceptual performance in visual search tasks. I. Contrast detection and discrimination SO JOURNAL OF THE OPTICAL SOCIETY OF AMERICA A-OPTICS IMAGE SCIENCE AND VISION LA English DT Article ID TARGET SELECTION; EYE-MOVEMENTS; SIGNAL-DETECTION; STRUCTURED BACKGROUNDS; SUPERIOR COLLICULUS; NEURONAL-ACTIVITY; PARIETAL CORTEX; NEURAL BASIS; NOISE; EFFICIENCY AB Humans use saccadic eye movements when they search for visual targets. We investigated the relationship between the visual processing used by saccades and perception during search by comparing saccadic and perceptual decisions under conditions in which each had access to equal visual information. We measured the accuracy of perceptual judgments and of the first search saccade over a wide range of target saliences [signal-to-noise ratios (SNRs)] in both a contrast-detection and a contrast-discrimination task. We found that saccadic and perceptual performances (1) were similar across SNRs, (2) showed similar task-dependent. differences, and (3) were well described by a model based on signal detection theory that explicitly includes observer uncertainty [M. R Eckstein et al., J. Opt. Soc. Am. A 14, 2406 (1997)]. Our results demonstrate that the accuracy of the first saccade provides much information about the observer's perceptual state at the time of the saccadic decision and provide evidence that saccades and perception use similar visual processing mechanisms for contrast detection and discrimination. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ Calif Santa Barbara, Dept Psychol, Santa Barbara, CA 93106 USA. RP Beutter, BR (reprint author), NASA, Ames Res Ctr, MS 262-2, Moffett Field, CA 94035 USA. NR 56 TC 52 Z9 53 U1 0 U2 3 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 0740-3232 J9 J OPT SOC AM A JI J. Opt. Soc. Am. A-Opt. Image Sci. Vis. PD JUL PY 2003 VL 20 IS 7 BP 1341 EP 1355 DI 10.1364/JOSAA.20.001341 PG 15 WC Optics SC Optics GA 694PX UT WOS:000183784000019 PM 12868639 ER PT J AU Murray, RF Beutter, BR Eckstein, MP Stone, LS AF Murray, RF Beutter, BR Eckstein, MP Stone, LS TI Saccadic and perceptual. performance in visual search tasks. II. Letter discrimination SO JOURNAL OF THE OPTICAL SOCIETY OF AMERICA A-OPTICS IMAGE SCIENCE AND VISION LA English DT Article ID BRAIN-STEM CONTROL; EYE-MOVEMENTS; SUPERIOR COLLICULUS; CONTRAST; SELECTION; OBJECTS; STIMULI AB Can the oculomotor system use shape cues to guide search saccades? Observers searched for target letters (D, U, or X) among distractors (the letter O in the discrimination task and blank locations in the detection task) in Gaussian white noise.. We measured the accuracy of first saccadic responses on each trial and perceptual (i.e., button-press) responses in separate trials with the stimulus duration chosen so that the saccadic and perceptual processing times were matched. We calculated the relative efficiency of saccadic decisions compared with perceptual decisions, eta(rel) = (d(sac)(')/d(per)('))(2). Relative efficiency was low but consistently greater than zero in discrimination tasks (15% +/- 6%) and high in detection tasks (60% +/- 10%). We conclude that the saccadic targeting system can use shape cues, but less efficiently than the perceptual system can. (C) 2003 Optical Society of America. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ Toronto, Dept Psychol, Toronto, ON M5S 3G3, Canada. Univ Calif Santa Barbara, Dept Psychol, Santa Barbara, CA 93106 USA. RP Stone, LS (reprint author), NASA, Ames Res Ctr, MS 262-2, Moffett Field, CA 94035 USA. NR 39 TC 6 Z9 6 U1 0 U2 0 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 0740-3232 J9 J OPT SOC AM A JI J. Opt. Soc. Am. A-Opt. Image Sci. Vis. PD JUL PY 2003 VL 20 IS 7 BP 1356 EP 1370 DI 10.1364/JOSAA.20.001356 PG 15 WC Optics SC Optics GA 694PX UT WOS:000183784000020 PM 12868640 ER PT J AU Suzen, YB Huang, PG Hultgren, LS Ashpis, DE AF Suzen, YB Huang, PG Hultgren, LS Ashpis, DE TI Predictions of separated and transitional boundary layers under low-pressure turbine airfoil conditions using an intermittency transport equation SO JOURNAL OF TURBOMACHINERY-TRANSACTIONS OF THE ASME LA English DT Article ID TURBULENCE MODELS; BYPASS TRANSITION; FLOW; LAMINAR; BUBBLES AB A new transport equation for the intermittency factor was proposed to predict separated and transitional boundary layers under low-pressure turbine airfoil conditions. The intermittent behavior of the transitional flows is taken into account and incorporated into computations by modifying the eddy viscosity, ut, with the intermittency factory. Turbulent quantities are predicted by using Menter's two-equation turbulence model (SST). The intermittency factor is obtained from a transport equation model, which not only can reproduce the experimentally observed streamwise variation of the intermittency in the transition zone, but also can provide a realistic cross-stream variation of the intermittency profile. In this paper, the intermittency model is used to predict a recent separated and transitional boundary layer experiment under low pressure turbine airfoil conditions. The experiment provides detailed measurements of velocity, turbulent kinetic energy and intermittency profiles for a number of Reynolds numbers and freestream turbulent intensity conditions and is suitable for validation purposes. Detailed comparisons of computational results with experimental data are presented and good agreements between the experiments and predictions are obtained. C1 Univ Kentucky, Dept Engn Mech, Lexington, KY 40506 USA. NASA, Glenn Res Ctr Lewis Field, Cleveland, OH 44135 USA. RP Suzen, YB (reprint author), Univ Kentucky, Dept Engn Mech, Lexington, KY 40506 USA. NR 26 TC 34 Z9 37 U1 3 U2 6 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA THREE PARK AVE, NEW YORK, NY 10016-5990 USA SN 0889-504X J9 J TURBOMACH JI J. Turbomach.-Trans. ASME PD JUL PY 2003 VL 125 IS 3 BP 455 EP 464 DI 10.1115/1.1580159 PG 10 WC Engineering, Mechanical SC Engineering GA 718QE UT WOS:000185157300006 ER PT J AU Schabetsberger, R Sztatecsny, M Drozdowski, G Brodeur, RD Swartzman, GL Wilson, MT Winter, AG Napp, JM AF Schabetsberger, R Sztatecsny, M Drozdowski, G Brodeur, RD Swartzman, GL Wilson, MT Winter, AG Napp, JM TI Size-dependent, spatial, and temporal variability of juvenile walleye pollock (Theragra chalcogramma) feeding at a structural front in the Southeast Bering Sea SO MARINE ECOLOGY-PUBBLICAZIONI DELLA STAZIONE ZOOLOGICA DI NAPOLI I LA English DT Article DE Theragra chalcogramma; walleye pollock; predation; diel feeding; frontal regions; Bering Sea ID PRIBILOF-ISLANDS; CALLORHINUS-URSINUS; PREY SELECTION; ALASKA; FISHES; ZOOPLANKTON; GROUNDFISH; PREDATION; PROXIMITY; PLANKTON AB The waters surrounding the Pribilof Islands are an important nursery ground for juvenile walleye pollock (Theragra chalcogramma ), an important forage fish in the pelagic food web of the productive Bering Sea shelf region. The diet of juvenile pollock was studied in two consecutive years along a transect line crossing from a well-mixed coastal domain, through a frontal region to stratified water farther offshore. Variability in stomach fullness was high and evidence for increased feeding intensity in the front was weak. Prey diversity and prey size generally increased with increasing fish size, shifting from predominantly small copepods to larger, more evasive prey items such as euphausiids, crab megalopae and fish. The diet of the fish reflected changes in the relative abundance of copepods and euphausiids in the prey fields between years. Juvenile pollock showed increased feeding rates at dusk, and stomach fullness as well as prey condition were generally lowest just before sunrise; however, the proportion of euphausiids increased in the diet of pollock caught at night, suggesting that some food was also ingested during darkness. Juvenile pollock and their euphausiid prey both vertically migrated above the thermocline at night, although each had a different daytime depth. C1 Oregon State Univ, Hatfield Marine Sci Ctr, Cooperat Inst Marine Resources Studies, Newport, OR 97365 USA. Univ Vienna, Inst Zool, A-1090 Vienna, Austria. Univ Vienna, Inst Ecol & Conservat Biol, A-1090 Vienna, Austria. Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, Hatfield Marine Sci Ctr, Newport, OR 97365 USA. Univ Washington, Appl Phys Lab, Seattle, WA 98105 USA. Alaska Fisheries Sci Ctr, Seattle, WA 98115 USA. Univ Washington, Sch Aquat & Fishery Sci, Seattle, WA 98105 USA. RP Schabetsberger, R (reprint author), Salzburg Univ, Inst Zool, Hellbrunnerstr 34, A-5020 Salzburg, Austria. NR 34 TC 16 Z9 16 U1 0 U2 9 PU BLACKWELL VERLAG GMBH PI BERLIN PA KURFURSTENDAMM 57, D-10707 BERLIN, GERMANY SN 0173-9565 J9 MAR ECOL-P S Z N I JI Mar. Ecol.-Pubbl. Stn. Zool. Napoli PD JUL PY 2003 VL 24 IS 2 BP 141 EP 164 DI 10.1046/j.1439-0485.2003.03819.x PG 24 WC Marine & Freshwater Biology SC Marine & Freshwater Biology GA 704NL UT WOS:000184345700004 ER PT J AU Antonelis, GA Baker, JD Polovina, JJ AF Antonelis, GA Baker, JD Polovina, JJ TI Improved body condition of weaned Hawaiian monk seal pups associated with El Nino events: Potential benefits to an endangered species SO MARINE MAMMAL SCIENCE LA English DT Article DE Hawaiian monk seal; Monachus schauinslandi; pup; condition; girth; mass; survival; El Nino ID PACIFIC SUBTROPICAL GYRE; GREY SEALS; GROWTH; CONSEQUENCES; SURVIVAL; MASS; SIZE AB Efforts to enhance recovery of endangered Hawaiian monk seals (Monachus schauinslandi) require an understanding of factors influencing population dynamics. This study examines relationships between body condition and survival of monk seal pups at French Frigate Shoals and Laysan Island and El Nino events. Girth measurements and mass estimates were used as indicators of pup body condition, and survival was evaluated from weaning to age 2. Linear models and logistic regression analysis were used to evaluate El Nino effects. Temporal trends in mean girth, mass, and survival were identified at both study sites. After accounting for temporal trends, girths were 3.7 cm and 2.7 cm greater during El Nino years at French Frigate Shoals and Laysan Island, respectively. Average mass estimates were significantly greater during El Nino years at French Frigate Shoals (2.6 kg increase), but were not significantly different at Laysan Island (1.8 kg increase). Weaned pups born at French Frigate Shoals during El Nino years survived significantly better, but this effect was not detected at Laysan Island. El Nino events probably affect pup condition and survival, but these parameters need to be monitored during future El Nino events to clarify these relationships. C1 NOAA, Natl Marine Fisheries Serv, SW Fisheries Sci Ctr, Honolulu Lab, Honolulu, HI 96822 USA. RP Antonelis, GA (reprint author), NOAA, Natl Marine Fisheries Serv, SW Fisheries Sci Ctr, Honolulu Lab, 2570 Dole St, Honolulu, HI 96822 USA. NR 33 TC 14 Z9 17 U1 2 U2 15 PU SOC MARINE MAMMALOGY PI LAWRENCE PA 1041 NEW HAMPSHIRE ST, LAWRENCE, KS 66044 USA SN 0824-0469 J9 MAR MAMMAL SCI JI Mar. Mamm. Sci. PD JUL PY 2003 VL 19 IS 3 BP 590 EP 598 DI 10.1111/j.1748-7692.2003.tb01323.x PG 9 WC Marine & Freshwater Biology; Zoology SC Marine & Freshwater Biology; Zoology GA 698HK UT WOS:000183992800010 ER PT J AU Duncan, RG Childers, BA Gifford, DK Pettit, DE Hickson, AW Duke, JC Brown, TL AF Duncan, RG Childers, BA Gifford, DK Pettit, DE Hickson, AW Duke, JC Brown, TL TI Use of a fiber optic distributed sensing system for nondestructive testing of aerospace structures SO MATERIALS EVALUATION LA English DT Article DE fiber optic sensing; optical frequency domain reflectometry; bragg gratings; aging aircraft; distributed sensing; nondestructive testing; aircraft health monitoring AB We report the use of a fiber optic distributed sensing system to monitor structural fatigue on an aircraft undergoing a full scale fatigue test. This technique involves using optical frequency domain reflectometry to demodulate the reflected signals from multiplexed bragg gratings that have been photoetched in the core of an optical fiber. The optical fibers, containing a high density of bragg gratings, were applied along the surface of a Lockheed Martin P-3C Orion fatigue test article to assess the suitability of this technique for long term structural damage detection and monitoring. The ability of this technology to accurately map strains with a high spatial resolution on the structure was assessed for both static and dynamic loading conditions. Preliminary results indicate good agreement with quasicollocated foil strain gages and demonstrate great potential for supplementing or providing an alternative to conventional nondestructive testing techniques. C1 Luna Innovat Inc, Blacksburg, VA 24060 USA. Lockheed Martin Aeronaut Co, Marietta, GA 30063 USA. Virginia Polytech Inst & State Univ, Blacksburg, VA 24060 USA. NASA, Langley Res Ctr, Hampton, VA 23669 USA. RP Duncan, RG (reprint author), Luna Innovat Inc, 2851 Commerce St, Blacksburg, VA 24060 USA. NR 10 TC 10 Z9 10 U1 0 U2 1 PU AMER SOC NON-DESTRUCTIVE TEST PI COLUMBUS PA 1711 ARLINGATE LANE PO BOX 28518, COLUMBUS, OH 43228-0518 USA SN 0025-5327 J9 MATER EVAL JI Mater. Eval. PD JUL PY 2003 VL 61 IS 7 BP 838 EP 843 PG 6 WC Materials Science, Characterization & Testing SC Materials Science GA 697AD UT WOS:000183919300005 ER PT J AU Brenner, MJ AF Brenner, MJ TI Non-stationary dynamics data analysis with wavelet-SVD filtering SO MECHANICAL SYSTEMS AND SIGNAL PROCESSING LA English DT Article ID TIME-FREQUENCY DISTRIBUTIONS; SINGULAR-VALUE DECOMPOSITION; MOMENTS; SPACES; SETS AB Non-stationary time-frequency analysis is used for identification and classification of aeroelastic and aeroservoelastic dynamics. Time-frequency multiscale wavelet processing generates discrete energy density distributions. The distributions are processed using the singular-value decomposition (SVD). Discrete density functions derived from the SVD generate moments that detect the principal features in the data. The SVD standard basis vectors are applied and then compared with a transformed-SVD, or TSVD, which reduces the number of features into more compact energy density concentrations. Finally, from the feature extraction, wavelet-based modal parameter estimation is applied. The primary objective is the automation of time-frequency analysis with modal system identification. The contribution is a more general approach in which distinct analysis tools are merged into a unified procedure for linear and non-linear data analysis. This method is first applied to aeroelastic pitch-plunge wing section models. Instability is detected in the linear system, and non-linear dynamics are observed from the time-frequency map and parameter estimates of the non-linear system. Aeroelastic and aeroservoelastic flight data from the drone for aerodynamic and structural testing and F18 aircraft are also investigated and comparisons made between the SVD and TSVD results. Input-output data are used to show that this process is an efficient and reliable tool for automated on-line analysis.Published by Elsevier Science Ltd. C1 NASA, Dryden Flight Res Ctr, Aerostruct Branch, Edwards AFB, CA 93523 USA. RP Brenner, MJ (reprint author), NASA, Dryden Flight Res Ctr, Aerostruct Branch, MS 48040DRS, Edwards AFB, CA 93523 USA. NR 26 TC 26 Z9 40 U1 0 U2 6 PU ACADEMIC PRESS LTD ELSEVIER SCIENCE LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 0888-3270 J9 MECH SYST SIGNAL PR JI Mech. Syst. Signal Proc. PD JUL PY 2003 VL 17 IS 4 BP 765 EP 786 DI 10.1006/mssp.2002.1512 PG 22 WC Engineering, Mechanical SC Engineering GA 672DH UT WOS:000182505500003 ER PT J AU Migliari, S Di Salvo, T Belloni, T van der Klis, M Fender, RP Campana, S Kouveliotou, C Mendez, M Lewin, WHG AF Migliari, S Di Salvo, T Belloni, T van der Klis, M Fender, RP Campana, S Kouveliotou, C Mendez, M Lewin, WHG TI Discovery of type I X-ray bursts from the low-mass X-ray binary 4U 1708-40 SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE accretion, accretion discs; stars : individual : 4U 1708-40; stars : neutron; X-rays : bursts; X-rays : general ID ENERGY CONCENTRATOR SPECTROMETER; ACCRETING NEUTRON-STARS; PERSISTENT EMISSION; ASTRONOMY SATELLITE; EXOSAT OBSERVATIONS; MXB 1728-34; 4U 1705-44; ON-BOARD; BEPPOSAX; OSCILLATIONS AB We report the discovery of type I X-ray bursts from the low-mass X-ray binary 4U 1708 - 40 during the 100-ks observation performed by BeppoSAX on 1999 August 15-16. Six X-ray bursts have been observed. The unabsorbed 2-10 keV fluxes of the bursts range from similar to3 to 9 x 10(-10) erg cm(-2) s(-1). A correlation between peak flux and fluence of the bursts is found, in agreement with the behaviour observed in other similar sources. There is a trend of the burst flux to increase with the time interval from the previous burst. From the value of the persistent flux we infer a mass accretion rate , which may correspond to the mixed hydrogen/helium burning regime triggered by thermally unstable hydrogen. We have also analysed a BeppoSAX observation performed on 2001 August 22 and previous RXTE observations of 4U 1708 - 40, where no bursts have been observed; we find persistent fluxes of more than a factor of 7 higher than the persistent flux observed during the BeppoSAX observation showing X-ray bursts. C1 Univ Amsterdam, Astron Inst Anton Pannekoek, NL-1098 SJ Amsterdam, Netherlands. Ctr High Energy Astrophys, NL-1098 SJ Amsterdam, Netherlands. Osserv Astron Brera, INAF, I-23807 Merate, LC, Italy. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. Univ Space Res Assoc, NSSTC, Huntsville, AL 35805 USA. SRON, Natl Inst Space Res, NL-3584 CA Utrecht, Netherlands. MIT, Ctr Space Res, Cambridge, MA 02139 USA. MIT, Dept Phys, Cambridge, MA 02139 USA. RP Migliari, S (reprint author), Univ Amsterdam, Astron Inst Anton Pannekoek, Kruislaan 403, NL-1098 SJ Amsterdam, Netherlands. EM migliari@astro.uva.nl RI Di Salvo, Tiziana/F-3973-2012; Mendez, Mariano/C-8011-2012; OI Di Salvo, Tiziana/0000-0002-3220-6375; Mendez, Mariano/0000-0003-2187-2708; Campana, Sergio/0000-0001-6278-1576 NR 37 TC 8 Z9 8 U1 0 U2 0 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 JUL 1 PY 2003 VL 342 IS 3 BP 909 EP 914 DI 10.1046/j.1365-8711.2003.06597.x PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 692XB UT WOS:000183684600019 ER PT J AU Nguyen, P Ng, HT Kong, J Cassell, AM Quinn, R Li, J Han, J McNeil, M Meyyappan, M AF Nguyen, P Ng, HT Kong, J Cassell, AM Quinn, R Li, J Han, J McNeil, M Meyyappan, M TI Epitaxial directional growth of indium-doped tin oxide nanowire arrays SO NANO LETTERS LA English DT Article ID RAY PHOTOELECTRON-SPECTROSCOPY; SNO2 THIN-FILMS; MECHANISM AB In this report, we show controlled in-situ doping of a single crystalline metal oxide nanowire, using indium-doped tin oxide (In-SnO2) as an example, during a heteroepitaxial growth process. Highly regular and high-density arrays of In-SnO2 nanowires, which demonstrate three-and four-fold growth symmetry, are obtained directly on optical sapphire substrates. Similar synthesis strategies, involving careful selection of desired growth conditions and smart manipulation of favorable thermodynamic properties, could be extended to production of various doped metal oxide nanowires. C1 NASA, Ames Res Ctr, Ctr Nanotechnol, Moffett Field, CA 94035 USA. San Jose State Univ, Dept Chem Engn, San Jose, CA 95192 USA. Eloret Corp, Sunnyvale, CA 94087 USA. RP Ng, HT (reprint author), NASA, Ames Res Ctr, Ctr Nanotechnol, Moffett Field, CA 94035 USA. RI Li, Jun/H-7771-2013 OI Li, Jun/0000-0002-3689-8946 NR 17 TC 107 Z9 108 U1 7 U2 49 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 JUL PY 2003 VL 3 IS 7 BP 925 EP 928 DI 10.1021/nl0342186 PG 4 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 700HV UT WOS:000184107300011 ER PT J AU Li, J Lu, YJ Ye, Q Cinke, M Han, J Meyyappan, M AF Li, J Lu, YJ Ye, Q Cinke, M Han, J Meyyappan, M TI Carbon nanotube sensors for gas and organic vapor detection SO NANO LETTERS LA English DT Article AB A gas sensor, fabricated by the simple casting of single-walled carbon nanotubes (SWNTs) on an interdigitated electrode (IDE), is presented for gas and organic vapor detection at room temperature. The sensor responses are linear for concentrations of sub ppm to hundreds of ppm with detection limits of 44 ppb for NO2 and 262 ppb for nitrotoluene. The time is on the order of seconds for the detection response and minutes for the recovery. The variation of the sensitivity is less than 6% for all of the tested devices, comparable with commercial metal oxide or polymer microfilm sensors while retaining the room-temperature high sensitivity of the SWNT transistor sensors and manufacturability of the commercial sensors. The extended detection capability from gas to organic vapors is attributed to direct charge transfer on individual semiconducting SWNT conductivity with additional electron hopping effects on intertube conductivity through physically adsorbed molecules between SWNTs. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. ELORET Corp, Sunnyvale, CA 94087 USA. RP Li, J (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 14 TC 862 Z9 878 U1 31 U2 286 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 JUL PY 2003 VL 3 IS 7 BP 929 EP 933 DI 10.1021/nl034220x PG 5 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 700HV UT WOS:000184107300012 ER PT J AU Martin-Gonzalez, M Snyder, GJ Prieto, AL Gronsky, R Sands, T Stacy, AM AF Martin-Gonzalez, M Snyder, GJ Prieto, AL Gronsky, R Sands, T Stacy, AM TI Direct electrodeposition of highly dense 50 nm Bi2Te3-ySey nanowire arrays SO NANO LETTERS LA English DT Article ID THERMOELECTRIC FIGURE; PHONON CONFINEMENT; QUANTUM-WELL; THIN-FILMS; MERIT AB Films and arrays of 200 and 50 nm diameter wires of Bi2Te3-xSex have been electrodeposited in the following general reaction: 2Bi(3+) + (3-y)HTeO2+ + (y)H2SeO3 + (9+y)H+ + 18e(-) --> Bi2Te3-ySey + (6+y)H2O. Films produced from an electrolyte of 0.0075 M Bi, 0,0090 M Te, and 0.0010 M Se in 1 M HNO3 at a potential of similar to0 V vs Ag/AgCl are single phase with composition Bi2Te2.6Se0.4 as determined by X-ray diffraction, energy-dispersive X-ray spectroscopy, and scanning electron microscopy. Similar conditions yield arrays of 200 and 50 nm Bi2Te3-ySey wires when deposited into porous alumina templates. The wires are single phase, crystalline, and textured, with up to 85% pore filling. C1 Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. CALTECH, Jet Prop Lab, Thermoelect Mat & Devices Team, Pasadena, CA 91109 USA. Univ Calif Berkeley, Dept Mat Sci & Engn, Berkeley, CA 94720 USA. RP Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. EM marisol@icmm.cnm.csic.es RI Sands, Timothy/D-2133-2009; Snyder, G. Jeffrey/E-4453-2011; Snyder, G/I-2263-2015; Martin-Gonzalez, Marisol/E-7076-2010 OI Sands, Timothy/0000-0001-9718-6515; Snyder, G. Jeffrey/0000-0003-1414-8682; Martin-Gonzalez, Marisol/0000-0002-5687-3674 NR 26 TC 128 Z9 131 U1 1 U2 60 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1530-6984 EI 1530-6992 J9 NANO LETT JI Nano Lett. PD JUL PY 2003 VL 3 IS 7 BP 973 EP 977 DI 10.1021/nl034079s PG 5 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 700HV UT WOS:000184107300021 ER PT J AU Steinberg, R AF Steinberg, R TI Soft matter, slow dynamics and art SO NATURE MATERIALS LA English DT Editorial Material C1 NASA, Fluid Dynam Div, John Glenn Res Ctr, Cleveland, OH USA. NR 6 TC 2 Z9 2 U1 0 U2 0 PU NATURE PUBLISHING GROUP PI LONDON PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 1476-1122 J9 NAT MATER JI Nat. Mater. PD JUL PY 2003 VL 2 IS 7 BP 427 EP 429 DI 10.1038/nmat932 PG 3 WC Chemistry, Physical; Materials Science, Multidisciplinary; Physics, Applied; Physics, Condensed Matter SC Chemistry; Materials Science; Physics GA 696ND UT WOS:000183892200002 PM 12876563 ER PT J AU Verkhoglyadova, OP Dasgupta, B Tsurutani, BT AF Verkhoglyadova, OP Dasgupta, B Tsurutani, BT TI Model for vortex turbulence with discontinuities in the solar wind SO NONLINEAR PROCESSES IN GEOPHYSICS LA English DT Article ID TANGENTIAL DISCONTINUITIES; ALFVEN WAVES; INTERPLANETARY DISCONTINUITIES; PLASMA; MAGNETOSPHERE; VORTICES; MAGNETOHYDRODYNAMICS; IONOSPHERE; VELOCITY; ULYSSES AB A model of vortex with embedded discontinuities in plasma flow is developed in the framework of ideal MHD in a low beta plasma. Vortex structures are considered as a result of 2-D evolution of nonlinear shear Alfven waves in the heliosphere. Physical properties of the solutions and vector fields are analyzed and the observational aspects of the model are discussed. The ratio of normal components to the discontinuity B(r)/V(r) can be close to -2. The alignment between velocity and magnetic field vectors takes place. Spacecraft crossing such vortices will typically observe a pair of discontinuities, but with dissimilar properties. Occurrence rate for different discontinuity types is estimated and agrees with observations in high-speed solar wind stream. Discontinuity crossing provides a backward rotation of magnetic field vector and can be observed as part of a backward arc. The Ulysses magnetometer data obtained in the fast solar wind are compared with the results of theoretical modelling. C1 Natl Taras Shevchenko Univ Kiev, Dept Space Phys & Astron, UA-252601 Kiev, Ukraine. Univ Calif Riverside, Inst Geophys & Planetary Phys, Riverside, CA 92521 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91103 USA. RP Verkhoglyadova, OP (reprint author), Natl Taras Shevchenko Univ Kiev, Dept Space Phys & Astron, UA-252601 Kiev, Ukraine. EM olgav@citrus.ucr.edu OI Verkhoglyadova, Olga/0000-0002-9295-9539 NR 29 TC 11 Z9 11 U1 0 U2 0 PU COPERNICUS GESELLSCHAFT MBH PI GOTTINGEN PA BAHNHOFSALLEE 1E, GOTTINGEN, 37081, GERMANY SN 1023-5809 J9 NONLINEAR PROC GEOPH JI Nonlinear Process Geophys. PD JUL-SEP PY 2003 VL 10 IS 4-5 BP 335 EP 343 PG 9 WC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences SC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences GA 778PP UT WOS:000189250200004 ER PT J AU Horton, W Weigel, RS Vassiliadis, D Doxas, I AF Horton, W Weigel, RS Vassiliadis, D Doxas, I TI Substorm classification with the WINDMI model SO NONLINEAR PROCESSES IN GEOPHYSICS LA English DT Article ID INTERPLANETARY MAGNETIC-FIELD; MAGNETOSPHERIC SUBSTORMS; GEOMAGNETIC-ACTIVITY; NORTHWARD TURNINGS; IONOSPHERE SYSTEM; DYNAMICS; FILTERS AB The results of a genetic algorithm optimization of the WINDMI model using the Blanchard-McPherron substorm data set is presented. A key result from the large-scale computations used to search for convergence in the predictions over the database is the finding that there are three distinct types of v(x)B(s)-AL waveforms characterizing substorms. Type I and III substorms are given by the internally-triggered WINDMI model. The analysis reveals an additional type of event, called a type II substorm, that requires an external trigger as in the northward turning of the IMF model of Lyons (1995). We show that incorporating an external trigger, initiated by a fast northward turning of the IMF, into WINDMI, a low-dimensional model of substorms, yields improved predictions of substorm evolution in terms of the AL index. Intrinsic database uncertainties in the timing between the ground-based AL electrojet signal and the arrival time at the magnetopause of the IMF data measured by spacecraft in the solar wind prevent a sharp division between type I and II events. However, within these timing limitations we find that the fraction of events is roughly 40% type I, 40% type II, and 20% type III. C1 Univ Texas, Austin, TX 78712 USA. NASA, Goddard Space Flight Ctr, NRC, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, USRA, Greenbelt, MD 20771 USA. Univ Colorado, Dept Phys, Boulder, CO 80309 USA. RP Horton, W (reprint author), Univ Texas, Austin, TX 78712 USA. EM horton@physics.utexas.edu NR 49 TC 11 Z9 11 U1 0 U2 1 PU EUROPEAN GEOPHYSICAL SOC PI KATLENBURG-LINDAU PA MAX-PLANCK-STR 13, 37191 KATLENBURG-LINDAU, GERMANY SN 1023-5809 J9 NONLINEAR PROC GEOPH JI Nonlinear Process Geophys. PD JUL-SEP PY 2003 VL 10 IS 4-5 BP 363 EP 371 PG 9 WC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences SC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences GA 778PP UT WOS:000189250200007 ER PT J AU Loewenstein, M Mushotzky, R AF Loewenstein, M Mushotzky, R TI The nature of dark matter in elliptical galaxies: Chandra observations of NGC 4636 SO NUCLEAR PHYSICS B-PROCEEDINGS SUPPLEMENTS LA English DT Article; Proceedings Paper CT 5th International UCLA Symposium on Sources and Detection of Dark Matter and Dark Energy in the Universe CY FEB 20-22, 2002 CL MARINA DEL REY, CALIFORNIA AB We determine the total enclosed mass profile from 0.7 to 35 kpc in the elliptical galaxy NGC 4636 based on the hot interstellar medium temperature profile measured using the Chandra X-ray Observatory, and other X-ray and optical data. The total mass increases as r(1.2) to a good approximation over this range in radii, attaining a total of similar to 1.5 x 10(12) M-circle dot (corresponding to M-tot/L-V = 40) at 35 kpc. We find that at least half, and as much as 80%, of the mass within the optical half-light radius is non-luminous, implying an exceptionally low baryon fraction in NGC 4636. The large inferred dark matter concentration and central dark matter density, consistent with the upper end of the range expected for standard cold dark matter halos, imply that mechanisms proposed to explain low dark matter densities in less massive galaxies are not effective in elliptical galaxies. C1 NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. Univ Maryland, Dept Astron, College Pk, MD 20742 USA. RP Loewenstein, M (reprint author), NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Code 662, Greenbelt, MD 20771 USA. NR 5 TC 11 Z9 11 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0920-5632 J9 NUCL PHYS B-PROC SUP JI Nucl. Phys. B-Proc. Suppl. PD JUL PY 2003 VL 124 BP 91 EP 94 DI 10.1016/S0920-5632(03)02085-1 PG 4 WC Physics, Particles & Fields SC Physics GA 703UE UT WOS:000184298700016 ER PT J AU Dick, R Blasi, P Kolb, EW AF Dick, R Blasi, P Kolb, EW TI Ultrahigh energy cosmic rays from dark matter annihilation SO NUCLEAR PHYSICS B-PROCEEDINGS SUPPLEMENTS LA English DT Article; Proceedings Paper CT 5th International UCLA Symposium on Sources and Detection of Dark Matter and Dark Energy in the Universe CY FEB 20-22, 2002 CL MARINA DEL REY, CA ID UNIVERSE; DECAY; BARYOGENESIS; INFLATION; SPECTRUM; BOSONS AB Annihilation of clumped superheavy dark matter provides an interesting explanation for the origin of ultrahigh energy cosmic rays. The predicted anisotropy signal provides a unique signature for this scenario. C1 Univ Saskatchewan, Dept Phys & Engn Phys, Saskatoon, SK S7N 5E2, Canada. Osserv Astrofis Arcetri, INAF, I-50125 Florence, Italy. NASA, Fermilab Astrophys Ctr, Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. Univ Chicago, Enrico Fermi Inst, Dept Astron & Astrophys, Chicago, IL 60637 USA. RP Dick, R (reprint author), Univ Saskatchewan, Dept Phys & Engn Phys, 116 Sci Pl, Saskatoon, SK S7N 5E2, Canada. RI Dick, Rainer/H-5182-2011; Blasi, Pasquale/O-9345-2015 OI Blasi, Pasquale/0000-0003-2480-599X NR 37 TC 2 Z9 2 U1 1 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0920-5632 EI 1873-3832 J9 NUCL PHYS B-PROC SUP JI Nucl. Phys. B-Proc. Suppl. PD JUL PY 2003 VL 124 BP 201 EP 204 DI 10.1016/S0920-5632(03)02106-6 PG 4 WC Physics, Particles & Fields SC Physics GA 703UE UT WOS:000184298700037 ER PT J AU Milman, MH Turyshev, SG AF Milman, MH Turyshev, SG TI Observational model for microarcsecond astrometry with the Space Interferometry Mission SO OPTICAL ENGINEERING LA English DT Article DE Space Interferometry Mission; metrology; path-length feedforward; astrometry; modeling ID WHITE-LIGHT FRINGE; SIM; ERROR AB The Space Interferometry Mission (SIM) is a space-based long-baseline optical interferometer for precision astrometry. One of the primary objectives of the SIM instrument is to accurately determine the directions to a grid of stars, together with their proper motions and par allaxes, improving a priori knowledge by nearly three orders of magnitude. The basic astrometric observable of the instrument is the path-length delay, a measurement made by a combination of internal metrology measurements that determine the distance the starlight travels through the two arms of the interferometer and a measurement of the white light stellar fringe to find the point of equal path length. Because this operation requires a nonnegligible integration time to accurately measure the stellar fringe position, the interferometer baseline vector is not stationary over this time period, as its absolute length and orientation are time-varying. This conflicts with the consistency condition necessary for extracting the astrometric parameters, which requires a stationary baseline vector. We address how the time-varying baseline is "regularized" so that it can act as a single baseline vector for multiple stars, and thereby establishing the fundamental operation of the instrument. (C) 2003 Society of Photo-Optical Instrumentation Engineers. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Milman, MH (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 16 TC 13 Z9 13 U1 0 U2 0 PU SPIE-INT SOCIETY OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98225 USA SN 0091-3286 J9 OPT ENG JI Opt. Eng. PD JUL PY 2003 VL 42 IS 7 BP 1873 EP 1883 DI 10.1117/1.1576405 PG 11 WC Optics SC Optics GA 700HL UT WOS:000184106500004 ER PT J AU Jia, WY Monge, K Fernandez, F AF Jia, WY Monge, K Fernandez, F TI Energy transfer from the host to EU3+ in ZnO SO OPTICAL MATERIALS LA English DT Article; Proceedings Paper CT 8th IUMRS International Conference on Electronic Materials (IUMRS/ICEM) CY JUN 10-14, 2002 CL XIAN, PEOPLES R CHINA SP Chinese Mat Res Soc, Int Union Mat Res Soc DE photoluminescence; energy transfer; ZnO; Eu3+; II-IV semiconductor ID SEMICONDUCTING ZINC-OXIDE; RARE-EARTH IONS; VISIBLE EMISSION; PHOTOLUMINESCENCE; SPECTROSCOPY; ULTRAVIOLET; GAN AB Undoped, and Eu2O3,Li- and EuF3,Li-codoped ZnO samples were prepared through solid state chemical reaction. Sharp exciton emission lines in UV were detected at 10 K, and a strong green emission band at 500 nm were observed at both 10 K and room temperature in the undoped ZnO samples. Emission and excitation spectra revealed that the energy transfer from the host to Eu3+ was very weak in ZnO:1%Eu2O3,Li. In contrast, quite efficient energy transfer from the host to Eu3+ was observed in the samples of ZnO:1%EuF3,Li. Possible physical reasons of the enhancement of energy transfer are discussed. (C) 2003 Elsevier Science B.V. All rights reserved. C1 Univ Puerto Rico, Dept Phys, NASA, Trop Ctr Earth & Space Studies, Mayaguez, PR 00681 USA. RP Jia, WY (reprint author), Univ Puerto Rico, Dept Phys, NASA, Trop Ctr Earth & Space Studies, POB 5000, Mayaguez, PR 00681 USA. OI Fernandez, Felix/0000-0002-0710-6751 NR 22 TC 66 Z9 73 U1 1 U2 7 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0925-3467 J9 OPT MATER JI Opt. Mater. PD JUL-AUG PY 2003 VL 23 IS 1-2 BP 27 EP 32 DI 10.1016/S0925-3467(03)00054-5 PG 6 WC Materials Science, Multidisciplinary; Optics SC Materials Science; Optics GA 697AC UT WOS:000183919200006 ER PT J AU Ristori, P Otero, L Fochesatto, J Flamant, PH Wolfram, E Quel, E Piacentini, R Holben, B AF Ristori, P Otero, L Fochesatto, J Flamant, PH Wolfram, E Quel, E Piacentini, R Holben, B TI Aerosol optical properties measured in Argentina: wavelength dependence and variability based on sun photometer measurements SO OPTICS AND LASERS IN ENGINEERING LA English DT Article DE aerosols; AERONET; air quality ID ANTHROPOGENIC AEROSOLS; SENSITIVITY; EXTINCTION; MODEL AB This paper deals with the spectral dependence and time variability of Angstrom wavelength exponent scaling law (alpha), which is the spectral varying slope of the logarithmic relationship between aerosol optical depths (tau) and the wavelength (lambda). It is commonly used to retrieve intensive air masses optical properties such as aerosol size distribution from extensive quantities (tau) and Angstrom turbidity coefficient (beta). This spectral variation of alpha is studied at different wavelengths from measurements taken by ground-based sun photometer covering from near-infrared to ultraviolet range. We analyze the spectral measurement of aerosols optical depths at eight specific selected wavelengths from 340 to 1020 nm using the sun photometer measurements from AErosol RObotic NETwork (AERONET) from NASA. Data from the entire year 2000 were used from instruments deployed at two different sites covering the regions of Argentina as northcentral at Cordoba CETT (31.5S, 64AW) and "pampa humeda" at Buenos Aires CEILAP (34.5S, 58.5W). A new approach of Angstrom wavelength exponent spectral variation was developed to take into account with a more accurate precision the significant curvature appearing in the logarithmic relation between tau and lambda. Using the direct spectral solar radiation set, time series of Angstrom coefficient of turbidity and wavelength scaling law was computed with a day to day data base clustering with uncertainty lower than 0.01 in the optical depth reconstruction over the bulk sun photometer measurements. Temporal series of constant and spectral dependence of wavelength exponent scaling law and turbidity coefficient was derived and shown to vary in space and time. Different meteorological forcing for both sites was evidenced using a regression coefficient analysis to well assess the spectral dependence of wavelength exponent coefficient due to the different cumulating mode of particles and air masses origin at different sites. This spectral decomposition is a key issue in aerosols analysis of steady state and regional scale intrusion episodes with strong connection to their potential contribution of pollution episodes in air-quality problems on urban environment. (C) 2003 Elsevier Science Ltd. All rights reserved. C1 CEILAP, CITEFA, CONICET, Buenos Aires, DF, Argentina. Ecole Polytech, Meteorol Dynam Lab, Palaiseau, France. Inst Fis Rosario, Rosario, Argentina. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Fochesatto, J (reprint author), CEILAP, CITEFA, CONICET, Zufriategui 4380-1603,Juan Bautista de la Salle 4, Buenos Aires, DF, Argentina. NR 27 TC 8 Z9 8 U1 0 U2 3 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0143-8166 J9 OPT LASER ENG JI Opt. Lasers Eng. PD JUL-AUG PY 2003 VL 40 IS 1-2 BP 91 EP 104 AR PII S0143-8166(02)00057-X DI 10.1016/S0143-8166(02)00057-X PG 14 WC Optics SC Optics GA 665TT UT WOS:000182137900010 ER PT J AU Roller, CA Clark, JB AF Roller, CA Clark, JB TI Short-duration space flight and hearing loss SO OTOLARYNGOLOGY-HEAD AND NECK SURGERY LA English DT Article ID NOISE; DAMAGE AB OBJECTIVES: The study goal was to determine whether a single Space Shuttle mission can induce decrements in astronaut hearing. STUDY DESIGN. We retrospectively compared audiogram information obtained from Space Shuffle astronauts at 10 days preflight, day of return (R + 0), 3 days after landing return (R + 3), and at a mean delayed postflight follow-up of 8 months. RESULTS: Temporary threshold shift (mean, 4.6 dB) was noted in R + 0 versus preflight conditions (P < 0.01). Small permanent threshold shifts (mean, 0.83 dB) were found at R + 3 and postflight follow-up compared with preflight in the lower frequencies (500 to 2000 Hz), and corresponding pure tone, average (P < 0.001). CONCLUSIONS AND SIGNIFICANCE. The data indicate that a single Shuffle flight can induce a substantial temporary threshold shift and a small but statistically significant permanent threshold shift, particularly in the frequencies involved in speech reception. Although single-mission effects are small, cumulative effects over several missions may ultimately produce clinically significant hearing loss. C1 Baylor Coll Med, Dept Otolaryngol & Commun Sci, Houston, TX 77030 USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Roller, CA (reprint author), Baylor Coll Med, Dept Otolaryngol, 1 Baylor Plaza, Houston, TX 77030 USA. OI Clark, Jonathan/0000-0002-1162-1238 NR 11 TC 1 Z9 11 U1 0 U2 0 PU MOSBY, INC PI ST LOUIS PA 11830 WESTLINE INDUSTRIAL DR, ST LOUIS, MO 63146-3318 USA SN 0194-5998 J9 OTOLARYNG HEAD NECK JI Otolaryngol. Head Neck Surg. PD JUL PY 2003 VL 129 IS 1 BP 98 EP 106 DI 10.1016/S0194-5998(03)00523-0 PG 9 WC Otorhinolaryngology; Surgery SC Otorhinolaryngology; Surgery GA 704YB UT WOS:000184368300017 PM 12869924 ER PT J AU Ruthruff, E Pashler, HE Hazeltine, E AF Ruthruff, E Pashler, HE Hazeltine, E TI Dual-task interference with equal task emphasis: Graded capacity sharing or central postponement? SO PERCEPTION & PSYCHOPHYSICS LA English DT Article ID PSYCHOLOGICAL REFRACTORY-PERIOD; EXECUTIVE COGNITIVE-PROCESSES; RESPONSE-SELECTION; MULTIPLE BOTTLENECKS; COMPUTATIONAL THEORY; OVERLAPPING TASKS; PERFORMANCE; MECHANISMS AB Most studies using the psychological refractory period (PRP) design suggest that dual-task performance is limited by a central bottleneck. Because subjects are usually told to emphasize Task 1, however, the bottleneck might reflect a strategic choice rather than a structural limitation. To evaluate the possibility that central operations can proceed in parallel, albeit with capacity limitations, we conducted two dual-task experiments with equal task emphasis. In both experiments, subjects tended to either group responses together or respond to one task well before the other. In addition, stimulus-response compatibility effects were roughly constant across stimulus onset asynchronies (SOAs). At the short SOA, compatibility effects also carried over onto response times for the other task. This pattern of results is difficult to reconcile with the possibility that subjects share capacity roughly equally between simultaneous central operations. However, this pattern is consistent with the existence of a structural central bottleneck. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ Calif San Diego, La Jolla, CA 92093 USA. RP Ruthruff, E (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. FU NIMH NIH HHS [MH45584] NR 40 TC 61 Z9 62 U1 1 U2 6 PU PSYCHONOMIC SOC INC PI AUSTIN PA 1710 FORTVIEW RD, AUSTIN, TX 78704 USA SN 0031-5117 J9 PERCEPT PSYCHOPHYS JI Percept. Psychophys. PD JUL PY 2003 VL 65 IS 5 BP 801 EP 816 DI 10.3758/BF03194816 PG 16 WC Psychology; Psychology, Experimental SC Psychology GA 712WM UT WOS:000184822100012 PM 12956587 ER PT J AU Sergeev, AV Mitin, VV Karasik, BS Gershenson, ME AF Sergeev, AV Mitin, VV Karasik, BS Gershenson, ME TI Superconducting nanosensors with mesoscopic number of quasiparticles SO PHYSICA E-LOW-DIMENSIONAL SYSTEMS & NANOSTRUCTURES LA English DT Article; Proceedings Paper CT 4th International Symposium on Nanostructures and Mesoscopic Systems (NanoMES 2003) CY FEB 17-21, 2003 CL TEMPE, ARIZONA DE sensor; detector; counter; single-photon; Andreev mirrors; terahertz ID SINGLE-PHOTON DETECTOR; RANGE; FILMS AB Novel approach to detection of low-energy (submillimeter and infrared) photons is based on implementation of the electron heating in superconducting nanostructures with small number of quasiparticles. In a hot-electron sensor, the incoming quanta generate nonequilibrium quasiparticles, which affect either the resistivity (transition-edge sensor) or the inductance (kinetic-inductance sensor operating in the superconducting state). The sensitivity of this sensor is limited by equilibrium fluctuations of the number of quasiparticle excitations, and a small number of quasiparticles is the key issue for high performance. The relaxation time in superconducting structures can be controlled over the range from 10 ps (outdiffusion of quasiparticles) to 0.1 s (phonon cooling). Therefore, hot-electron sensors can be employed as relatively slow ultra-sensitive detectors or fast photon counters, depending on a dominant cooling mechanism. The counter can resolve photons of submillimeter and terahertz ranges with the counting rate of 10(11) count/s. Hot-electron nanosensors are expected to deliver the unique perfon-nance: the noise equivalent power of 10(-20) W/rootHz and the energy resolution of 10(-21)-10(-23) J. (C) 2003 Elsevier B.V. All rights reserved. C1 Wayne State Univ, Dept ECE, Detroit, MI 48202 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Rutgers State Univ, Dept Phys & Astron, Piscataway, NJ 08854 USA. RP Sergeev, AV (reprint author), Wayne State Univ, Dept ECE, Detroit, MI 48202 USA. RI Karasik, Boris/C-5918-2011 NR 10 TC 4 Z9 4 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1386-9477 J9 PHYSICA E JI Physica E PD JUL PY 2003 VL 19 IS 1-2 BP 173 EP 177 DI 10.1016/S1386-9477(03)00303-5 PG 5 WC Nanoscience & Nanotechnology; Physics, Condensed Matter SC Science & Technology - Other Topics; Physics GA 710CV UT WOS:000184664000032 ER PT J AU Yu, DZ Mei, RW Luo, LS Shyy, W AF Yu, DZ Mei, RW Luo, LS Shyy, W TI Viscous flow computations with the method of lattice Boltzmann equation SO PROGRESS IN AEROSPACE SCIENCES LA English DT Review DE lattice Boltzmann equation; force evaluation; grid refinement; multi-block; boundary condition; single-relaxation-time; multi-relaxation-time ID RAYLEIGH-TAYLOR INSTABILITY; NAVIER-STOKES EQUATIONS; LARGE-EDDY SIMULATIONS; EXTENDED SELF-SIMILARITY; DISCRETE-VELOCITY MODELS; REYNOLDS-NUMBER FLOWS; TURBULENT FLUID-FLOW; BOUNDARY-CONDITIONS; POROUS-MEDIA; PARTICULATE SUSPENSIONS AB The method of lattice Boltzmann equation (LBE) is a kinetic-based approach for fluid flow computations. This method has been successfully applied to the multi-phase and multi-component flows. To extend the application of LBE to high Reynolds number incompressible flows, some critical issues need to be addressed, noticeably flexible spatial resolution, boundary treatments for curved solid wall, dispersion and mode of relaxation, and turbulence model. Recent developments in these aspects are highlighted in this paper. These efforts include the study of force evaluation methods, the development of multi-block methods which provide a means to satisfy different resolution requirement in the near wall region and the far field and reduce the memory requirement and computational time, the progress in constructing the second-order boundary condition for curved solid wall, and the analyses of the single-relaxation-time and multiple-relaxation-time models in LBE. These efforts have lead to successful applications of the LBE method to the simulation of incompressible laminar flows and demonstrated the potential of applying the LBE method to higher Reynolds flows. The progress in developing thermal and compressible LBE models and the applications of LBE method in multi-phase flows, multi-component flows, particulate suspensions, turbulent flow, and micro-flows are reviewed. (C) 2003 Published by Elsevier Science Ltd. C1 Univ Florida, Dept Mech & Aerosp Engn, Gainesville, FL 32611 USA. NASA, Langley Res Ctr, ICASE, Hampton, VA 23681 USA. RP Mei, RW (reprint author), Univ Florida, Dept Mech & Aerosp Engn, 231 Aerosp Bldg POB 116250, Gainesville, FL 32611 USA. EM rwm@mae.ufl.edu RI Luo, Li-Shi/A-4561-2011; OI Luo, Li-Shi/0000-0003-1215-7892; Shyy, Wei/0000-0001-6670-5394 NR 209 TC 442 Z9 458 U1 11 U2 125 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0376-0421 J9 PROG AEROSP SCI JI Prog. Aeosp. Sci. PD JUL PY 2003 VL 39 IS 5 BP 329 EP 367 DI 10.1016/S0376-0421(03)00003-4 PG 39 WC Engineering, Aerospace SC Engineering GA 693QV UT WOS:000183730600001 ER PT J AU Smith, JA Baker, MB Weinman, JA AF Smith, JA Baker, MB Weinman, JA TI Do forest fires affect lightning? SO QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY LA English DT Article DE aerosols; positive cloud-to-ground lightning ID LIQUID WATER; CLOUD; SMOKE; ELECTRIFICATION; THUNDERSTORMS AB Lightning statistics are analysed downwind of forest fires in 1998 and 2000. The previously studied 1998 case shows anomalously high frequencies of positive cloud-to-ground, lightning (+CG%) in the Southern Great Plains region of the USA, coincident with the smoke plume from forest fires in Central America. Fires in the northwestern USA in summer 2000 produced a smoke pall commensurate, with the 1998 fires, but were not accompanied by statistically significant lightning anomalies. Analyses of meteorological data reveal that the southern Great Plains region was abnormally dry and hot during the period of anomalous lightning 1998. Using a 1.5-dimensional thunderstorm model on a day with high +CG% 15 May 1998. we find that whereas the percentage of positive cloud-to-ground lightning did not change significantly with changes in cloud condensation nuclei, adding moisture to the model significantly decreases the percentage of positive cloud-to-ground lightning, making it closet to the climatological norm. C1 Univ Washington, Dept Earth & Space Sci, Seattle, WA 98195 USA. NASA, Goddard Space Flight Ctr, Microwave Sensors Branch, Greenbelt, MD 20771 USA. RP Smith, JA (reprint author), Univ Washington, Dept Earth & Space Sci, Box 351310, Seattle, WA 98195 USA. OI Smith, Jeremy/0000-0003-2028-0866 NR 22 TC 10 Z9 10 U1 1 U2 2 PU ROYAL METEOROLOGICAL SOC PI READING PA 104 OXFORD ROAD, READING RG1 7LJ, BERKS, ENGLAND SN 0035-9009 J9 Q J ROY METEOR SOC JI Q. J. R. Meteorol. Soc. PD JUL PY 2003 VL 129 IS 593 BP 2651 EP 2670 DI 10.1256/qj.02.175 PN B PG 20 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 719DD UT WOS:000185187600010 ER PT J AU Weaver, K AF Weaver, K TI The galactic odd couple SO SCIENTIFIC AMERICAN LA English DT Article C1 NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. Johns Hopkins Univ, Baltimore, MD 21218 USA. RP Weaver, K (reprint author), NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. NR 5 TC 1 Z9 1 U1 0 U2 0 PU SCI AMERICAN INC PI NEW YORK PA 415 MADISON AVE, NEW YORK, NY 10017 USA SN 0036-8733 J9 SCI AM JI Sci.Am. PD JUL PY 2003 VL 289 IS 1 BP 34 EP 41 PG 8 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 688TU UT WOS:000183453000028 PM 12840944 ER PT J AU Shepard, A McCurdy, A AF Shepard, A McCurdy, A TI The link project: A NOAA and NASA partnership - Working to promote ocean and space research and exploration through technology innovation SO SEA TECHNOLOGY LA English DT Article C1 Univ N Carolina, Natl Undersea Res Ctr, SE & Gulf Mexico Reg, Wilmington, NC 28401 USA. enterACKed, NASA, Oceanog Outreach Project, Arlington, VA USA. RP Shepard, A (reprint author), Univ N Carolina, Natl Undersea Res Ctr, SE & Gulf Mexico Reg, Wilmington, NC 28401 USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU COMPASS PUBL INC PI ARLINGTON PA SUITE 1000 1117 N 19 ST, ARLINGTON, VA 22209 USA SN 0093-3651 J9 SEA TECHNOL JI Sea Technol. PD JUL PY 2003 VL 44 IS 7 BP 47 EP + PG 5 WC Engineering, Ocean SC Engineering GA 704GW UT WOS:000184332100010 ER PT J AU Decker, KLM Wang, D Waite, C Scherbatskoy, T AF Decker, KLM Wang, D Waite, C Scherbatskoy, T TI Snow removal and ambient air temperature effects on forest soil temperatures in Northern Vermont SO SOIL SCIENCE SOCIETY OF AMERICA JOURNAL LA English DT Article ID AGGREGATE STABILITY; HARDWOOD FOREST/; CHEMISTRY; DYNAMICS; NITROGEN; MANIPULATION; ECOSYSTEM/; STRESS; FROST; DEPTH AB We measured deciduous forest soil temperatures under control (unmanipulated) and snow-free (where snow is manually removed) conditions for four winters (at three soil depths) to determine effects of a snow cover reduction such as may occur as a result of climate change on Vermont forest soils. The four winters we studied were characterized as: 'cold and snowy', 'warm with low snow', 'cold with low snow', and 'cool with low snow'. Snow-free soils were colder than controls at 5- and 15-cm depth for all years, and at all depths in the two cold winters. Soil thermal variability generally decreased with both increased snow cover and soil depth. The effect of snow cover on soil freeze-thaw events was highly dependent on both the depth of snow and the soil temperature. Snow kept the soil warm and reduced soil temperature variability, but often this caused soil to remain near 0degreesC, resulting in more freeze-thaw events under snow at one or more soil depths. During the 'cold snowy' winter, soils under snow had daily averages consistently >0degreesC, whereas snow-free soil temperatures commonly dropped below -3degreesC. During the 'warm' year, temperatures of soil under snow were often lower than those of snow-free soils. The warmer winter resulted in less snow cover to insulate soil from freezing in the biologically active top 30 cm. The possible consequences of increased soil freezing include more root mortality and nutrient loss, which would potentially alter ecosystem dynamics, decrease productivity of some tree species, and increase sugar maple (Acer saccharum Marshall) mortality in northern hardwood forests. C1 Univ Vermont, George D Aiken Ctr, Sch Nat Resources, Burlington, VT 05401 USA. RP Decker, KLM (reprint author), NASA, Ames Res Ctr, Ecosyst Sci & Technol Branch, MS 242-4, Moffett Field, CA 94035 USA. RI Decker, Kelly/J-1831-2012 NR 21 TC 75 Z9 93 U1 7 U2 30 PU SOIL SCI SOC AMER PI MADISON PA 677 SOUTH SEGOE ROAD, MADISON, WI 53711 USA SN 0361-5995 J9 SOIL SCI SOC AM J JI Soil Sci. Soc. Am. J. PD JUL-AUG PY 2003 VL 67 IS 4 BP 1234 EP 1242 PG 9 WC Soil Science SC Agriculture GA 700XP UT WOS:000184136700021 ER PT J AU Petrovay, K AF Petrovay, K TI Consistent one-dimensional model for the turbulent tachocline SO SOLAR PHYSICS LA English DT Article ID LATITUDINAL DIFFERENTIAL ROTATION; SOLAR TACHOCLINE; STRATIFIED FLUIDS; MAGNETIC-FIELD; SHEAR; EVOLUTION; INSTABILITY; TRANSPORT; STABILITY; ZONE AB The first consistent model for the turbulent tachocline is presented, with the turbulent diffusivity computed within the model instead of being specified arbitrarily. For the origin of the 3D turbulence a new mechanism is proposed. Owing to the strongly stable stratification, the mean radial shear is stable, while the horizontal shear is expected to drive predominantly horizontal, quasi-2D motions in thin slabs. Here I suggest that a major source of 3D overturning turbulent motions in the tachocline is the secondary shear instability due to the strong, random vertical shear arising between the uncorrelated horizontal flows in neighboring slabs. A formula for the vertical diffusivity due to this turbulence, Equation (9), is derived and applied in a simplified 1D model of the tachocline. It is found that Maxwell stresses due to an oscillatory poloidal magnetic field of a few hundred gauss are able to confine the tachocline to a thickness less than 5 Mm. The integral scale of the 3D overturning turbulence is the buoyancy scale, on the order of 10 km, and its velocity amplitude is a few m s(-1), yielding a vertical turbulent diffusivity on the order of 10(8) cm(2) s(-1). C1 Eotvos Lorand Univ, Dept Astron, H-1518 Budapest, Hungary. NASA, Ames Res Ctr, Ctr Turbulence Res, Moffett Field, CA 94035 USA. RP Petrovay, K (reprint author), Eotvos Lorand Univ, Dept Astron, Pf 32, H-1518 Budapest, Hungary. OI Petrovay, Kristof/0000-0002-1714-2027 NR 32 TC 9 Z9 9 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 JUL PY 2003 VL 215 IS 1 BP 17 EP 30 DI 10.1023/A:1024880723754 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 702YF UT WOS:000184251900002 ER PT J AU Temmer, M Veronig, A Hanslmeier, A AF Temmer, M Veronig, A Hanslmeier, A TI Does solar flare activity lag behind sunspot activity? SO SOLAR PHYSICS LA English DT Article ID X-RAY FLARES; NORTH-SOUTH ASYMMETRY; MAGNETIC-FIELD; STATISTICAL-ANALYSIS; OSCILLATING DYNAMO; CYCLE; NUMBERS; FLUX AB Recently, Wheatland and Litvinenko (2001) have suggested that over the solar cycle both the flaring rate and the magnetic free energy in the corona lag behind the energy supply to the system. To test this model result, we analyzed the evolution of solar flare occurrence with regard to sunspot numbers (as well as sunspot areas), using Ha flare data available for the period 1955-2002, and soft X-ray flare data (GOES 1-8 Angstrom) for the period 1976-2002. For solar cycles 19, 21, and 23, we find a characteristic time lag between flare activity and sunspot activity in the range 10 less than or similar to tau less than or similar to 15 months, consistent with the model predictions by Wheatland and Litvinenko (2001). The phenomenon turns out to be more prominent for highly energetic flares. The investigation of solar activity separately for the northern and southern hemisphere allows us to exclude any bias due to overlapping effects from the activity of both hemispheres and confirms the dynamic relevance of the delay phenomenon. Yet, no characteristic time lag tau > 0 is found for solar cycles 20 and 22. The finding that in odd-numbered cycles flare activity is statistically delayed with respect to sunspot activity, while in even-numbered cycles it is not, suggests a connection to the 22-year magnetic cycle of the Sun. Further insight into the connection to the 22-year magnetic cycle could possibly be gained when a 22-year variation in the energy supply rate is taken into account in the Wheatland and Litvinenko (2001) model. The existence of a 22-year modulation in the energy supply rate is suggested by the empirical Gnevyshev-Ohl rule, and might be caused by a relic solar field. C1 Graz Univ, Inst Geophys Astrophys & Meteorol, A-8010 Graz, Austria. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Temmer, M (reprint author), Graz Univ, Inst Geophys Astrophys & Meteorol, Univ Pl 5, A-8010 Graz, Austria. RI Veronig, Astrid/B-8422-2009; OI Temmer, Manuela/0000-0003-4867-7558 NR 25 TC 27 Z9 28 U1 0 U2 1 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-0938 J9 SOL PHYS JI Sol. Phys. PD JUL PY 2003 VL 215 IS 1 BP 111 EP 126 DI 10.1023/A:1024843010048 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 702YF UT WOS:000184251900008 ER PT J AU Zhuang, Q McGuire, AD Melillo, JM Clein, JS Dargaville, RJ Kicklighter, DW Myneni, RB Dong, J Romanovsky, VE Harden, J Hobbie, JE AF Zhuang, Q McGuire, AD Melillo, JM Clein, JS Dargaville, RJ Kicklighter, DW Myneni, RB Dong, J Romanovsky, VE Harden, J Hobbie, JE TI Carbon cycling in extratropical terrestrial ecosystems of the Northern Hemisphere during the 20th century: a modeling analysis of the influences of soil thermal dynamics SO TELLUS SERIES B-CHEMICAL AND PHYSICAL METEOROLOGY LA English DT Review ID ATMOSPHERIC CO2 MEASUREMENTS; SPRUCE/MOSS BOREAL FOREST; NASA SCATTEROMETER NSCAT; NET PRIMARY PRODUCTION; FREEZE-THAW CYCLES; HIGH-LATITUDES; NITROGEN DEPOSITION; INCREASING CO2; CLIMATE-CHANGE; UNITED-STATES AB There is substantial evidence that soil thermal dynamics are changing in terrestrial ecosystems of the Northern Hemisphere and that these dynamics have implications for the exchange of carbon between terrestrial ecosystems and the atmosphere. To date, large-scale biogeochemical models have been slow to incorporate the effects of soil thermal dynamics on processes that affect carbon exchange with the atmosphere. In this study we incorporated a soil thermal module (STM), appropriate to both permafrost and non-permafrost soils, into a large-scale ecosystem model, version 5.0 of the Terrestrial Ecosystem Model (TEM). We then compared observed regional and seasonal patterns of atmospheric CO2 to simulations of carbon dynamics for terrestrial ecosystems north of 30degreesN between TEM 5.0 and an earlier version of TEM (version 4.2) that lacked a STM. The timing of the draw-down of atmospheric CO2 at the start of the growing season and the degree of draw-down during the growing season were substantially improved by the consideration of soil thermal dynamics. Both versions of TEM indicate that climate variability and change promoted the loss of carbon from temperate ecosystems during the first half of the 20th century, and promoted carbon storage during the second half of the century. The results of the simulations by TEM suggest that land-use change in temperate latitudes (30-60degreesN) plays a stronger role than climate change in driving trends for increased uptake of carbon in extratropical terrestrial ecosystems (30-90degreesN) during recent decades. In the 1980s the TEM 5.0 simulation estimated that extratropical terrestrial ecosystems stored 0.55 Pg C yr(-1), with 0.24 Pg C yr(-1) in North America and 0.31 Pg C yr(-1) in northern Eurasia. From 1990 through 1995 the model simulated that these ecosystems stored 0.90 Pg C yr-1, with 0.27 Pg C yr(-1) stored in North America and 0.63 Pg C yr(-1) stored in northern Eurasia. Thus, in comparison to the 1980s, simulated net carbon storage in the 1990s was enhanced by an additional 0.35 Pg C yr(-1) in extratropical terrestrial ecosystems, with most of the additional storage in northern Eurasia. The carbon storage simulated by TEM 5.0 in the 1980s and 1990s was lower than estimates based on other methodologies, including estimates by atmospheric inversion models and remote sensing and inventory analyses. This suggests that other issues besides the role of soil thermal dynamics may be responsible, in part, for the temporal and spatial dynamics of carbon storage of extratropical terrestrial ecosystems. In conclusion, the consideration of soil thermal dynamics and terrestrial cryospheric processes in modeling the global carbon cycle has helped to reduce biases in the simulation of the seasonality of carbon dynamics of extratropical terrestrial ecosystems. This progress should lead to an enhanced ability to clarify the role of other issues that influence carbon dynamics in terrestrial regions that experience seasonal freezing and thawing of soil. C1 Marine Biol Lab, Ctr Ecosyst, Woods Hole, MA 02543 USA. Univ Alaska, Dept Biol & Wildlife, Fairbanks, AK 99775 USA. Univ Alaska Fairbanks, US Geol Survey, Alaska Cooperat Fish & Wildlife Res Unit, Fairbanks, AK 99775 USA. Univ Alaska, Inst Arctic Biol, Fairbanks, AK 99775 USA. NCAR, Ecosyst Dynam & Atmosphere, Boulder, CO 80305 USA. Boston Univ, Dept Geog, Boston, MA 02215 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Alaska, Inst Geophys, Fairbanks, AK 99775 USA. US Geol Survey, Menlo Pk, CA 94025 USA. RP Zhuang, Q (reprint author), Marine Biol Lab, Ctr Ecosyst, 7 MBL St, Woods Hole, MA 02543 USA. EM qzhuang@mbl.edu RI Zhuang, Qianlai/A-5670-2009; Myneni, Ranga/F-5129-2012; OI Dargaville, Roger/0000-0002-0103-5198 NR 112 TC 103 Z9 110 U1 5 U2 24 PU CO-ACTION PUBLISHING PI JARFALLA PA RIPVAGEN 7, JARFALLA, SE-175 64, SWEDEN SN 0280-6509 EI 1600-0889 J9 TELLUS B JI Tellus Ser. B-Chem. Phys. Meteorol. PD JUL PY 2003 VL 55 IS 3 BP 751 EP 776 DI 10.1034/j.1600-0889.2003.00060.x PG 26 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 700YA UT WOS:000184137700002 ER PT J AU Gutsev, GL Andrews, L Bauschlicher, CW AF Gutsev, GL Andrews, L Bauschlicher, CW TI Similarities and differences in the structure of 3d-metal monocarbides and monoxides SO THEORETICAL CHEMISTRY ACCOUNTS LA English DT Review DE 3d-metal monoxide; 3d-metal monocarbide; density functional theory; electron affinity; ionization energy ID ELECTRONIC POPULATION ANALYSIS; MOLECULAR WAVE FUNCTIONS; DENSITY-FUNCTIONAL METHODS; ANION PHOTOELECTRON-SPECTROSCOPY; AB-INITIO INVESTIGATIONS; TRANSITION-METAL OXIDES; GAUSSIAN-BASIS SETS; LOW-LYING STATES; JET-COOLED FEC; BOND-ENERGIES AB The structure and properties of the monocarbides ScC, TiC, VC, CrC, MnC, FeC, CoC, NiC.. CuC, ZnC and their negatively and positively charged ions together with 3d-metal monoxide cations are calculated by density functional theory (DFT) and hybrid DFT methods. In addition to the spectroscopic constants, the computed properties include the electron affinities, ionization energies, and dissociation energies. These results along with our previous results for the neutral and negatively charged 3d-metal monoxides allow a detailed comparison of similarity and differences in the bonding of the metal oxides and carbides. These results are compared with results obtained using other theoretical approaches and with experiment. Chemical bonding, analyzed using the natural bond orbital scheme, was found to be rather different in the 3d-metal monocarbides and monoxides. C1 NASA, Ames Res Ctr, Space Telescope Div, Moffett Field, CA 94035 USA. Univ Virginia, Dept Chem, Charlottesville, VA 22901 USA. RP Gutsev, GL (reprint author), NASA, Ames Res Ctr, Space Telescope Div, Mail Stop 230-3, Moffett Field, CA 94035 USA. NR 105 TC 122 Z9 122 U1 2 U2 24 PU SPRINGER-VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 1432-881X J9 THEOR CHEM ACC JI Theor. Chem. Acc. PD JUL PY 2003 VL 109 IS 6 BP 298 EP 308 DI 10.1007/s00214-003-0428-4 PG 11 WC Chemistry, Physical SC Chemistry GA 716GR UT WOS:000185020900002 ER PT J AU Dube, MJ Bollea, D Jones, WR Marchetti, M Jansen, MJ AF Dube, MJ Bollea, D Jones, WR Marchetti, M Jansen, MJ TI A new synthetic hydrocarbon liquid lubricant for space applications SO TRIBOLOGY LETTERS LA English DT Article DE synthetic hydrocarbon; space tribology ID VACUUM 4-BALL TRIBOMETER AB Synthetic hydrocarbon liquid lubricants (based on polyalphaolefins) have been developed for use in space applications. These materials have been fully characterized and their physical properties reported which include: kinematic and absolute viscosity, viscosity index, vapor pressure, evaporation, specific gravity, pour point, coefficient of thermal expansion, refractive index, and flow activation energy. In addition, tribological properties under ultrahigh vacuum conditions have been determined. These include: lubricated lifetimes using a spiral orbit tribometer (SOT) and vacuum four-ball wear rates. These values are compared to existing state-of-the-art space lubricants. C1 Nye Lubricants Inc, New Bedford, MA 02742 USA. NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. Sest Inc, Middleburgh Hts, OH 44130 USA. RP Dube, MJ (reprint author), Nye Lubricants Inc, New Bedford, MA 02742 USA. NR 24 TC 24 Z9 26 U1 5 U2 12 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 1023-8883 J9 TRIBOL LETT JI Tribol. Lett. PD JUL PY 2003 VL 15 IS 1 BP 3 EP 8 DI 10.1023/A:1023470420857 PG 6 WC Engineering, Chemical; Engineering, Mechanical SC Engineering GA 668WQ UT WOS:000182318500002 ER PT J AU Dellacorte, C AF Dellacorte, C TI The effects of substrate material and thermal processing atmosphere on the strength of PS304: A high temperature solid lubricant coating SO TRIBOLOGY TRANSACTIONS LA English DT Article; Proceedings Paper CT 58th Annual Meeting of the Society-of-Tribologists-and-Lubrication-Engineers CY APR 28-MAY 01, 2003 CL NEW YORK, NEW YORK SP Soc Tribologists & Lubricat Engineers DE solid lubricants; aerospace; high temperature; coatings AB PS304, a plasma spray deposited solid lubricant coating developed for high temperature sliding contacts was deposited on nine different substrate metals, heat treated at 650degreesC in either air or argon and subsequently tested for strength using a commercially available pull-off adhesion test. Some samples were examined metallographically to help elucidate and explain the results. As-deposited coatings exhibit pull-off strengths typically between 16 and 20 MPa with failure occurring (cohesively) within the coating. Heat treatment in argon at 650degreesC results in a slight increase in coating (cohesive) strength of about 30 percent to 21 to 27 MPa. Heat treatment in air at 650degreesC results in a draman. c increase in strength to over 30 MPa, exceeding the strength of the epoxy used in the pull test. Cross section metallographic analyses show that no microstructural coating changes occur following the argon heat treatments, however, exposure to air at 650degreesC gives rise to the formation of a second chromium-rich phase precipitate within the PS304 NiCr constituent which provides a strengthening effect and a slight (similar to5 percent) coating thickness increase. Subsequent heat treatments do not result in any further coating changes. Based upon these studies, PS304 is a suitable coating for use on a wide variety of high temperature substrates and must be heat treated following deposition to enhance strength and ensure dimensional stability. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Dellacorte, C (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. NR 5 TC 21 Z9 23 U1 1 U2 6 PU SOC TRIBOLOGISTS & LUBRICATION ENGINEERS PI PARK RIDGE PA 840 BUSSE HIGHWAY, PARK RIDGE, IL 60068 USA SN 1040-2004 J9 TRIBOL T JI Tribol. Trans. PD JUL PY 2003 VL 46 IS 3 BP 361 EP 368 DI 10.1080/10402000308982638 PG 8 WC Engineering, Mechanical SC Engineering GA 704XW UT WOS:000184367800011 ER PT J AU Marchetti, M Jones, WR Pepper, SV Jansen, MJ Predmore, RE AF Marchetti, M Jones, WR Pepper, SV Jansen, MJ Predmore, RE TI In-situ, on-demand lubrication system for space mechanisms SO TRIBOLOGY TRANSACTIONS LA English DT Article DE vacuum and space; aerospace tribology; ball bearings; lubricant application methods ID BALL-BEARING RETAINERS; OIL EXCHANGE AB Many of today's spacecraft have long mission lifetimes. Whatever the lubrication method selected, the initial lubricant charge is required to last the entire mission. Fluid lubricant losses are mainly due to evaporation, tribo-degradation, and oil creep out of the tribological regions. In the past, several techniques were developed to maintain the appropriate amount of oil in the system. They were based on oil reservoirs (cartridges, impregnated porous parts), barrier films, and labyrinth seals. Nevertheless, all these systems have had limited success or have not established a proven record for space missions. The system reported here provides to the ball-race contact fresh lubricant in-situ and on demand when the ball bearing is close to failure. The lubricant is stored in a porous cartridge attached to the inner or the outer ring of a ball bearing. The oil is released by heating the cartridge to eject oil, taking advantage of the greater thermal expansion of the oil compared to the porous network. The heating may be activated by torque increases that signal the depletion of oil in the contact. The low surface tension of the oil compared to the ball bearing material is utilized and the close proximity of the cartridge to the moving balls allows the lubricant to reach the ball-race contacts. This oil re-supply system avoided a mechanism failure, reduced torque to an acceptable level, and extended the life of the component. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. SEST Inc, Middlebugh Hts, OH 44130 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Marchetti, M (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. NR 52 TC 8 Z9 9 U1 1 U2 5 PU SOC TRIBOLOGISTS & LUBRICATION ENGINEERS PI PARK RIDGE PA 840 BUSSE HIGHWAY, PARK RIDGE, IL 60068 USA SN 1040-2004 J9 TRIBOL T JI Tribol. Trans. PD JUL PY 2003 VL 46 IS 3 BP 452 EP 459 DI 10.1080/10402000308982650 PG 8 WC Engineering, Mechanical SC Engineering GA 704XW UT WOS:000184367800023 ER PT J AU Morales, W Fusaro, R Kascak, A AF Morales, W Fusaro, R Kascak, A TI Permanent magnetic bearing for spacecraft applications SO TRIBOLOGY TRANSACTIONS LA English DT Article; Proceedings Paper CT 58th Annual Meeting of the Society-of-Tribologists-and-Lubrication-Engineers CY APR 28-MAY 01, 2003 CL NEW YORK, NEW YORK SP Soc Tribologists & Lubricat Engineers DE magnetic bearings; jewel bearings; space vehicles ID JEWEL BEARING AB A passive permanent magnetic bearing rig prototype was designed and constructed. The suspension of the rotor was provided by two sets of radial permanent magnetic bearings operating in the repulsive mode. The axial support was provided by jewel bearings on both ends of the rotor. Preliminary testing led to successful operation of the bearing prototype to speeds of 5500 rpm using an air impeller. Radial and axial stiffnesses of the permanent magnetic bearings were experimentally measured and then compared to finite element results. The natural damping of the rotor was measured and a damping coefficient was calculated. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. USA, Res Lab, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Morales, W (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. NR 10 TC 5 Z9 6 U1 0 U2 1 PU SOC TRIBOLOGISTS & LUBRICATION ENGINEERS PI PARK RIDGE PA 840 BUSSE HIGHWAY, PARK RIDGE, IL 60068 USA SN 1040-2004 J9 TRIBOL T JI Tribol. Trans. PD JUL PY 2003 VL 46 IS 3 BP 460 EP 464 DI 10.1080/10402000308982651 PG 5 WC Engineering, Mechanical SC Engineering GA 704XW UT WOS:000184367800024 ER PT J AU Loncar, M Scherer, A Qiu, YM AF Loncar, M Scherer, A Qiu, YM TI Photonic crystal laser sources for chemical detection SO APPLIED PHYSICS LETTERS LA English DT Article ID DEFECT; MODES; SLABS AB We have realized photonic crystal lasers that permit the introduction of analyte within the peak of the optical field of the lasing mode. We have explored the design compromises for developing such sensitive low-threshold spectroscopy sources, and demonstrate the operation of photonic crystal lasers in different ambient organic solutions. We show that nanocavity lasers can be used to perform spectroscopic tests on femtoliter volumes of analyte, and propose to use these lasers for high-resolution spectroscopy with single-molecule sensitivity. (C) 2003 American Institute of Physics. C1 CALTECH, Dept Elect Engn, Pasadena, CA 91125 USA. CALTECH, Jet Prop Lab, In Situ Technol & Expt Syst Sect, Pasadena, CA 91109 USA. RP Loncar, M (reprint author), CALTECH, Dept Elect Engn, MS 136-93, Pasadena, CA 91125 USA. NR 11 TC 229 Z9 229 U1 4 U2 23 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 JUN 30 PY 2003 VL 82 IS 26 BP 4648 EP 4650 DI 10.1063/1.1586781 PG 3 WC Physics, Applied SC Physics GA 694CZ UT WOS:000183757400006 ER PT J AU Cheung, IW Chin, KB Greene, ER Smart, MC Abbrent, S Greenbaum, SG Prakash, GKS Surampudi, S AF Cheung, IW Chin, KB Greene, ER Smart, MC Abbrent, S Greenbaum, SG Prakash, GKS Surampudi, S TI Electrochemical and solid state NMR characterization of composite PEO-based polymer electrolytes SO ELECTROCHIMICA ACTA LA English DT Article; Proceedings Paper CT 8th International Symposium on Polymer Electrolytes CY MAY 19-24, 2002 CL SANTA FE, NEW MEXICO SP USA, Res Off, USN, Res Off, US DOE DE PEO; NMR; polymer electrolytes ID RECHARGEABLE LITHIUM BATTERIES; CONDUCTIVITY; STABILITY AB A comprehensive matrix of composite poly(ethyleneoxide) (PEO)-based solid-state electrolytes was developed in order to systematically study a number of variables and their impact upon the electrochemical properties of the resulting materials. The different parameters studied in the fabrication of these materials include: (i) the lithium electrolyte salt type, (ii) the ether oxygen to lithium ratio, (iii) the molecular weight of PEO, (iv) the type of ceramic additive used, either aluminum oxide (Al2O3), silicon oxide (SiO2), or titanium oxide (TiO2), (v) the particle size of the additives used, and (vi) the concentration of additive (wt.%). The standard lithium salt used for the preparation of these electrolytes was lithium trifluoromethanesulfonate (lithium triflate or LiSO3CF3), which served as the baseline electrolyte salt. Other lithium salts investigated include: lithium perchlorate (LiClO4) and lithium bis-trifluoromethanesulfonimide (LiN(SO2CF3)(2)). Conductivity measurements were performed for each electrolyte membrane over a wide temperature range (23-100 degreesC). In addition, cyclic voltammetry measurements were performed on selected PEO membranes as a function of temperature to determine the impact of various parameters upon the electrochemical stability. It was observed that the parameter that displayed the most significant effect upon the PEO-base polymer conductivity was the lithium salt type employed. The lithium triflate salt-containing PEO polymers demonstrated the best mechanical properties before and after heat treatment. Ceramic fillers also appear to enhance the mechanical properties of PEO polymer electrolytes at temperatures above the melting point of PEO (60-70 degreesC). In addition to investigating the electrochemical characteristics of the composite membrane, solid state Li-7 NMR characterization was performed to study ionic mobility by measuring spectral line widths and lithium self-diffusion coefficients. It was determined that ceramic nanoparticle additives can enhance the Li+ diffusivity without a corresponding increase in polymer segmental mobility. (C) 2003 Elsevier Science Ltd. All rights reserved. C1 CALTECH, Jet Prop Lab, NASA, Pasadena, CA 91109 USA. Univ So Calif, Loker Hydrocarbon Res Inst, Los Angeles, CA 90089 USA. Univ So Calif, Dept Chem, Los Angeles, CA 90089 USA. CUNY Hunter Coll, Dept Phys, New York, NY 10021 USA. RP Smart, MC (reprint author), CALTECH, Jet Prop Lab, NASA, Pasadena, CA 91109 USA. RI Abbrent, Sabina/M-9812-2014 NR 27 TC 41 Z9 41 U1 9 U2 60 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0013-4686 J9 ELECTROCHIM ACTA JI Electrochim. Acta PD JUN 30 PY 2003 VL 48 IS 14-16 BP 2149 EP 2156 DI 10.1016/S0013-4686(03)00198-1 PG 8 WC Electrochemistry SC Electrochemistry GA 701NX UT WOS:000184174600029 ER PT J AU Hillard, U Sridhar, V Lettenmaier, DP McDonald, KC AF Hillard, U Sridhar, V Lettenmaier, DP McDonald, KC TI Assessing snowmelt dynamics with NASA scatterometer (NSCAT) data and a hydrologic process model SO REMOTE SENSING OF ENVIRONMENT LA English DT Article DE scatterometer; freeze-thaw; snow; hydrology ID TAIGA FORESTS; ERS-1 SAR; FROZEN; ALASKA; MELT; GHZ AB The presence of snow strongly impacts the exchange of moisture and energy between the land surface and atmosphere. In the interior of the northern hemisphere continents, snowmelt on frozen soils can cause or exacerbate major floods. Microwave remote sensing from satellite platforms has the potential to monitor the freeze-thaw status of soil and overlying snow packs over large areas. We evaluate the backscatter response of the NSCAT scatterometer to changing snow surface conditions, especially freeze and thaw status, using a macroscale hydrology model and the NSCAT backscatter data for the upper Mississippi River basin of the north central U.S. and the Boreal Ecosystem Atmosphere Study (BOREAS) region in central Canada. We compared the snowmelt conditions simulated by the Variable Infiltration Capacity (VIC) macroscale hydrology model driven with surface meteorological observations with NSCAT measurements for 1996-1997 snow season. A mid-winter thaw event (in February) and late season melt (April-May) are evaluated for both regions. Comparison of backscatter images with daily and hourly-modeled snow surface wetness and temperature showed that the model agreed with the backscatter for snow surface wetness on some days but not on others. Factors such as NSCAT overpass times, vegetation on the ground and their freeze-thaw state, and liquid moisture content appear to contribute to these discrepancies. (C) 2003 Elsevier Science Inc. All rights reserved. C1 Univ Washington, Dept Civil & Environm Engn, Seattle, WA 98195 USA. NRCE, Berkeley, CA 94702 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Univ Washington, Dept Civil & Environm Engn, Box 352700, Seattle, WA 98195 USA. EM dennis1@u.washington.edu RI lettenmaier, dennis/F-8780-2011 OI lettenmaier, dennis/0000-0003-3317-1327 NR 37 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 EI 1879-0704 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD JUN 30 PY 2003 VL 86 IS 1 BP 52 EP 69 DI 10.1016/S0034-4257(03)00068-3 PG 18 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA 697FV UT WOS:000183932300005 ER PT J AU Olson, CF Matthies, LH Schoppers, M Maimone, MW AF Olson, CF Matthies, LH Schoppers, M Maimone, MW TI Rover navigation using stereo ego-motion SO ROBOTICS AND AUTONOMOUS SYSTEMS LA English DT Article DE robot navigation; motion estimation; stereo vision; Mars rovers ID MOBILE ROBOT LOCALIZATION; IMAGE SEQUENCES AB Robust navigation for mobile robots over long distances requires an accurate method for tracking the robot position in the environment. Promising techniques for position estimation by determining the camera ego-motion from monocular or stereo sequences have been previously described. However, long-distance navigation requires both a high level of robustness and a low rate of error growth. In this paper, we describe a methodology for long-distance rover navigation that meets these goals using robust estimation of ego-motion. The basic method is a maximum-likelihood ego-motion algorithm that models the error in stereo matching as a normal distribution elongated along the (parallel) camera viewing axes. Several mechanisms are described for improving navigation robustness in the context of this methodology. In addition, we show that a system based on only camera ego-motion estimates will accumulate errors with super-linear growth in the distance traveled, owing to increasing orientation errors. When an absolute orientation sensor is incorporated, the error growth can be reduced to a linear function of the distance traveled. We have tested these techniques using both extensive simulation and hundreds of real rover images and have achieved a low, linear rate of error growth. This method has been implemented to run on-board a prototype Mars rover. (C) 2003 Elsevier Science B.V. All rights reserved. C1 Univ Washington, Bothell, WA 98011 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Univ Washington, 18115 Campus Way NE,Box 358534, Bothell, WA 98011 USA. NR 27 TC 119 Z9 132 U1 1 U2 8 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-8890 EI 1872-793X J9 ROBOT AUTON SYST JI Robot. Auton. Syst. PD JUN 30 PY 2003 VL 43 IS 4 BP 215 EP 229 DI 10.1016/S0921-8890(03)00004-6 PG 15 WC Automation & Control Systems; Computer Science, Artificial Intelligence; Robotics SC Automation & Control Systems; Computer Science; Robotics GA 690VK UT WOS:000183571000003 ER PT J AU DiRienzi, J Drachman, RJ AF DiRienzi, J Drachman, RJ TI Re-examination of a simplified model for positronium-helium scattering SO JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS LA English DT Article ID ORTHOPOSITRONIUM AB Using a local effective potential to account for electron exchange, Drachman and Houston (1970 J. Phys. B: At. Mol. Phys. 3 1657) analysed the zero-energy scattering of ortho-positronium by helium atoms in 1970. The idea was to use the existing static-exchange results to fit the parameters of the local potential and then to use the potential in a variational target-elastic calculation. The results were remarkably good, both for the scattering length and the annihilation parameter. Recently, however, a rigorous target-elastic calculation by Blackwood et al (1999 Phys. Rev. A 60 4454) disagreed so strongly with these old results that we have undertaken a re-examination. We find that the assumption made in the earlier work, that the direct potential is negligible compared with the exchange potential, is not quantitatively correct. C1 Coll Notre Dame Maryland, Baltimore, MD 21210 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP DiRienzi, J (reprint author), Coll Notre Dame Maryland, Baltimore, MD 21210 USA. NR 19 TC 6 Z9 6 U1 0 U2 4 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0953-4075 J9 J PHYS B-AT MOL OPT JI J. Phys. B-At. Mol. Opt. Phys. PD JUN 28 PY 2003 VL 36 IS 12 BP 2409 EP 2417 AR PII S0953-4075(03)60461-X DI 10.1088/0953-4075/36/12/302 PG 9 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 706CJ UT WOS:000184433900003 ER PT J AU Fernandez, JM Munoz, A Lopez, ARD Feria, FMV Dominguez-Rodriguez, A Singh, M AF Fernandez, JM Munoz, A Lopez, ARD Feria, FMV Dominguez-Rodriguez, A Singh, M TI Microstructure-mechanical properties correlation in siliconized silicon carbide ceramics SO ACTA MATERIALIA LA English DT Article DE siliconized SiC; porous material; creep; high temperature deformation; microstructure ID HIGH-TEMPERATURE CREEP; SIC SINGLE-CRYSTALS; SELF-DIFFUSION; RFSC CERAMICS; DEFORMATION; BEHAVIOR AB The microstructure and high temperature mechanical properties of siliconized silicon carbide ceramics (reaction bonded, reaction formed, and biomorphic SiC) have been investigated. The microstructural differences between these materials have been analyzed. Reaction formed and biomorphic SiC show better, high temperature compressive creep resistance and strength than reaction bonded SiC. Additionally, these two materials show a continuous decrease in the creep rate, which is more pronounced at higher temperature and silicon content. This behavior is explained in detail by using a model of creep controlled by a viscous intergranular phase. The maximum strengths were exhibited by the biomorphic SiC when compressed in the axial direction. The strength of reaction formed SiC is roughly the average between the strength of biomorphic SiC compressed in the axial and radial directions. The dependence of the high temperature compressive strength with the microstructure, and volume fraction of SiC is discussed in terms of the minimum solid area approach. (C) 2003 Acta Materialia Inc. Published by Elsevier Science Ltd. All rights reserved. C1 Univ Seville, Dept Fis Mat Condensada, Seville, Spain. NASA, Glenn Res Ctr, QSS Grp Inc, Cleveland, OH 44135 USA. RP Fernandez, JM (reprint author), Univ Seville, Dept Fis Mat Condensada, Apdo 1065, Seville, Spain. RI MARTINEZ FERNANDEZ, JULIAN/K-1826-2012; OI MARTINEZ FERNANDEZ, JULIAN/0000-0002-1199-6638; R. de Arellano Lopez, Antonio/0000-0002-7443-0244; Dominguez-Rodriguez, Arturo/0000-0003-1598-5669 NR 31 TC 30 Z9 31 U1 2 U2 30 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 JUN 27 PY 2003 VL 51 IS 11 BP 3259 EP 3275 DI 10.1016/S1359-6454(03)00157-5 PG 17 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 692KW UT WOS:000183661100019 ER PT J AU Mischna, MA Richardson, MI Wilson, RJ McCleese, DJ AF Mischna, MA Richardson, MI Wilson, RJ McCleese, DJ TI On the orbital forcing of Martian water and CO2 cycles: A general circulation model study with simplified volatile schemes SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article DE Mars; Martian climate; obliquity; Mars GCM; surface ice; surface layering ID POLAR LAYERED DEPOSITS; CHAOTIC OBLIQUITY; GROUND ICE; SEASONAL RESERVOIRS; LANDING SITES; MARS ODYSSEY; NEAR-SURFACE; ATMOSPHERE; PRESSURE; CLIMATE AB Variations in the Martian water and CO2 cycles with changes in orbital and rotational parameters are examined using the Geophysical Fluid Dynamics Laboratory Mars General Circulation Model. The model allows for arbitrary specification of obliquity, eccentricity, and argument of perihelion as well as the position and thickness of surface ice. Exchange of CO2 between the surface and atmosphere is modeled, generating seasonal cycles of surface ice and surface pressure. Water is allowed to exchange between the surface and atmosphere, cloud formation is treated, and both cloud and vapor are transported by modeled winds and diffusion. Exchange of water and CO2 with the subsurface is not allowed, and radiative effects of water vapor and clouds are not treated. The seasonal cycle of CO2 is found to become more extreme at high obliquity, as suggested by simple heat balance models. Maximum pressures remain largely the same, but the minima decrease substantially as more CO2 condenses in the more extensive polar night. Vapor and cloud abundances increase dramatically with obliquity. The stable location for surface ice moves equatorward with increasing obliquity, such that by 45degrees obliquity, water ice is stable in the tropics only. Ice is not spatially uniform, but rather found preferentially in regions of high thermal inertia or high topography. Eccentricity and argument of perihelion can provide a second-order modification to the distribution of surface ice by altering the temporal distribution of insolation at the poles. Further model simulations reveal the robustness of these distributions for a variety of initial conditions. Our findings shed light on the nature of near-surface, ice-rich deposits at midlatitudes and low-latitudes on Mars. C1 Univ Calif Los Angeles, Dept Earth & Space Sci, Los Angeles, CA 90095 USA. CALTECH, Div Geol & Planetary Sci, Pasadena, CA 91125 USA. Geophys Fluid Dynam Lab, Princeton, NJ 08540 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Mischna, MA (reprint author), Univ Calif Los Angeles, Dept Earth & Space Sci, 595 Charles Young Dr E, Los Angeles, CA 90095 USA. EM mischna@ucla.edu; mir@gps.caltech.edu NR 45 TC 141 Z9 142 U1 0 U2 3 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 JUN 27 PY 2003 VL 108 IS E6 AR 5062 DI 10.1029/2003JE002051 PG 25 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 708VV UT WOS:000184591300001 ER PT J AU Wang, J Mason, R VanDerveer, D Feng, K Bu, XR AF Wang, J Mason, R VanDerveer, D Feng, K Bu, XR TI Convenient preparation of a novel class of imidazo[1,5-a]pyridines: Decisive role by ammonium acetate in chemoselectivity SO JOURNAL OF ORGANIC CHEMISTRY LA English DT Article ID ACYLATION REACTIONS; IMIDAZO<1,5-A>PYRIDINES; DERIVATIVES; RECEPTOR; AGENTS; POTENT AB A facile and one-pot straightforward methodology has been developed to prepare a novel class of imidazo[1,5-a]-pyridines. A key role played by ammonium acetate in chemoselectivity has been examined. C1 Clark Atlanta Univ, Dept Chem, Atlanta, GA 30314 USA. Georgia Inst Technol, Sch Chem & Biochem, Atlanta, GA 30322 USA. Clark Atlanta Univ, NASA, Ctr High Performance Polymers & Composites, Atlanta, GA 30314 USA. RP Bu, XR (reprint author), Clark Atlanta Univ, Dept Chem, Atlanta, GA 30314 USA. EM xbu@cau.edu NR 22 TC 102 Z9 103 U1 1 U2 17 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0022-3263 J9 J ORG CHEM JI J. Org. Chem. PD JUN 27 PY 2003 VL 68 IS 13 BP 5415 EP 5418 DI 10.1021/jo0342020 PG 4 WC Chemistry, Organic SC Chemistry GA 692PQ UT WOS:000183669800060 PM 12816512 ER PT J AU Hahne, GE AF Hahne, GE TI Time as an observable in nonrelativistic quantum mechanics SO JOURNAL OF PHYSICS A-MATHEMATICAL AND GENERAL LA English DT Article ID TUNNELING TIMES; SOJOURN-TIME; TRANSMISSION; SCATTERING; BARRIER; DELAY AB The nonrelativistic Schrodinger equation for motion of a structureless particle in four-dimensional spacetime entails a well-known expression for the conserved four-vector field of local probability density and current that are associated with a quantum state solution to the equation. Under the physical assumption that each spatial, as well as the temporal, component of this current is observable, the position in time becomes an operator and an observable in that the weighted average value of the time of the particle's crossing of a complete hyperplane can be simply defined: the theory predicts, and experiment is presumed to be able to observe, the integral over the hyperplane of the normal component of probability current, weighted by the time coordinate. In conventional formulations the hyperplane is always spacelike, i.e. is a time = constant hyperplane in the Galilean relativity, and the result is then trivial. A nontrivial result is obtained if the plane is not of this type. When the spacetime coordinates are (t, x, y, z), the paper analyses in detail the case that the hyperplane is of the type z = constant. Particles can cross such a hyperplane in either direction, so,it proves convenient to introduce an indefinite metric, and correspondingly a sesquilinear inner product with non-Hilbert space structure, for the space of quantum states on such a surface. Since the metric is indefinite, an uncertainty principle involving the dispersion of the crossing time and the dispersion of its conjugate momentum does not appear to be derivable from the theory. A detailed formalism for computing average crossing times on a z = constant hyperplane, and average dwell times and delay times between a pair of z constant hyperplanes, is presented. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Hahne, GE (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 51 TC 8 Z9 8 U1 0 U2 2 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0305-4470 J9 J PHYS A-MATH GEN JI J. Phys. A-Math. Gen. PD JUN 27 PY 2003 VL 36 IS 25 BP 7149 EP 7172 AR PII S0305-4470(03)60664-5 DI 10.1088/0305-4470/36/25/316 PG 24 WC Physics, Multidisciplinary; Physics, Mathematical SC Physics GA 706CX UT WOS:000184435400018 ER PT J AU Golombek, MP AF Golombek, MP TI The surface of Mars: Not just dust and rocks SO SCIENCE LA English DT Editorial Material C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Golombek, MP (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 6 TC 3 Z9 3 U1 0 U2 1 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD JUN 27 PY 2003 VL 300 IS 5628 BP 2043 EP 2044 DI 10.1126/science.1082927 PG 2 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 694KZ UT WOS:000183774900031 PM 12829771 ER PT J AU Christensen, PR Bandfield, JL Bell, JF Gorelick, N Hamilton, VE Ivanov, A Jakosky, BM Kieffer, HH Lane, MD Jakosky, BM Kieffer, HH Lane, MD Malin, MC McConnochie, T McEwen, AS McSween, HY Mehall, GL Moersch, JE Nealson, KH Rice, JW Richardson, MI Ruff, SW Smith, MD Titus, TN Wyatt, MB AF Christensen, PR Bandfield, JL Bell, JF Gorelick, N Hamilton, VE Ivanov, A Jakosky, BM Kieffer, HH Lane, MD Jakosky, BM Kieffer, HH Lane, MD Malin, MC McConnochie, T McEwen, AS McSween, HY Mehall, GL Moersch, JE Nealson, KH Rice, JW Richardson, MI Ruff, SW Smith, MD Titus, TN Wyatt, MB TI Morphology and composition of the surface of Mars: Mars Odyssey THEMIS results SO SCIENCE LA English DT Article ID THERMAL EMISSION SPECTROMETER; GLOBAL SURVEYOR; MARTIAN SURFACE; ORBITER CAMERA; WHITE ROCK; INERTIA AB The Thermal Emission Imaging System (THEMIS) on Mars Odyssey has produced infrared to visible wavelength images of the martian surface that show lithologically distinct layers with variable thickness, implying temporal changes in the processes or environments during or after their formation. Kilometer-scale exposures of bedrockare observed; elsewhere airfall dust completely mantles the surface over thousands of square kilometers. Mars has compositional variations at 100-meter scales, for example, an exposure of olivine-rich basalt in the walls of Ganges Chasma. Thermally distinct ejecta facies occur around some craters with variations associated with crater age. Polar observations have identified temporal patches of water frost in the north polar cap. No thermal signatures associated with endogenic heat sources have been identified. C1 Arizona State Univ, Dept Geol Sci, Tempe, AZ 85287 USA. Cornell Univ, Dept Astron, Ithaca, NY 14853 USA. Univ Hawaii, Hawaii Inst Geophys & Planetol, Honolulu, HI 96822 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Colorado, LASP, Boulder, CO 80309 USA. US Geol Survey, Flagstaff, AZ 86001 USA. Planetary Sci Inst, Phoenix, AZ 85032 USA. Malin Space Sci Syst, San Diego, CA 92191 USA. Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. Univ Tennessee, Dept Geol Sci, Knoxville, TN 37996 USA. Univ So Calif, Los Angeles, CA 90089 USA. CALTECH, Div Geol & Planetary Sci, Pasadena, CA 91125 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Christensen, PR (reprint author), Arizona State Univ, Dept Geol Sci, Tempe, AZ 85287 USA. RI Moersch, Jeffrey/F-7189-2010; Smith, Michael/C-8875-2012; Ivanov, Anton/C-8944-2014 OI Ivanov, Anton/0000-0001-8376-8581 NR 30 TC 236 Z9 238 U1 3 U2 30 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD JUN 27 PY 2003 VL 300 IS 5628 BP 2056 EP 2061 DI 10.1126/science.1080885 PG 6 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 694KZ UT WOS:000183774900036 PM 12791998 ER PT J AU Mitrofanov, IG Zuber, MT Litvak, ML Boynton, WV Smith, DE Drake, D Hamara, D Kozyrev, AS Sanin, AB Shinohara, C Saunders, RS Tretyakov, V AF Mitrofanov, IG Zuber, MT Litvak, ML Boynton, WV Smith, DE Drake, D Hamara, D Kozyrev, AS Sanin, AB Shinohara, C Saunders, RS Tretyakov, V TI CO2 snow depth and subsurface water-ice abundance in the northern hemisphere of Mars SO SCIENCE LA English DT Article ID SUMMER TEMPERATURES; ORBITER CAMERA; POLAR-CAP; EVOLUTION; FROST; HYDROGEN; NEUTRONS; BEHAVIOR; DETECTOR; SURFACE AB Observations of seasonal variations of neutron flux from the high-energy neutron detector (HEND) on Mars Odyssey combined with direct measurements of the thickness of condensed carbon dioxide by the Mars Orbiter Laser Altimeter (MOLA) on Mars Global Surveyor show a latitudinal dependence of northern winter deposition of carbon dioxide. The observations are also consistent with a shallow substrate consisting of a layer with water ice overlain by a layer of drier soil. The lower ice-rich layer contains between 50 and 75 weight % water, indicating that the shallow subsurface at northern polar latitudes on Mars is even more water rich than that in the south. C1 Russian Acad Sci, Space Res Inst, Moscow 117997, Russia. MIT, Dept Earth Atmospher & Planetary Sci, Cambridge, MA 02139 USA. Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. NASA, Terr Phys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Tech Source, Santa Fe, NM 87505 USA. NASA Headquarters, Washington, DC 20514 USA. RP Mitrofanov, IG (reprint author), Russian Acad Sci, Space Res Inst, Moscow 117997, Russia. NR 28 TC 50 Z9 50 U1 0 U2 4 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD JUN 27 PY 2003 VL 300 IS 5628 BP 2081 EP 2084 DI 10.1126/science.1084350 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 694KZ UT WOS:000183774900042 PM 12829779 ER PT J AU Fromm, M Alfred, J Pitts, M AF Fromm, M Alfred, J Pitts, M TI A unified, long-term, high-latitude stratospheric aerosol and cloud database using SAM II, SAGE II, and POAM II/III data: Algorithm description, database definition, and climatology SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE PSC; aerosol; stratosphere; SAM; POAM; SAGE ID LIMB ATMOSPHERIC SPECTROMETER; NITRIC-ACID TRIHYDRATE; GAS-EXPERIMENT; POLAR VORTEX; POTENTIAL VORTICITY; ANTARCTIC VORTEX; EL-CHICHON; OZONE; WINTER; SATELLITE AB A 22 year, high-latitude, stratospheric aerosol and cloud database has been formed in a "unified'' manner by combining the Stratospheric Aerosol Measurement (SAM) II, Stratospheric Aerosol and Gas Measurement ( SAGE) II, Polar Ozone and Aerosol Measurement (POAM) II, and POAM III 1 mum aerosol extinction profiles. The database is "unified'' in that it embodies similar aerosol extinction measurements, uses a single meteorological data set, and employs a single algorithm for calculating background extinction and cloud detection thresholds. Latitude is constrained to poleward of 45degrees in each hemisphere. The Unified cloud detection algorithm and database are designed for the straightforward addition of new data when other compatible data sets (e.g., SAGE III) become available. "Unified'' cloud detection is similar to, but a refinement of, earlier attempts to identify polar stratospheric clouds (PSCs) with SAM II and POAM II data. The Unified algorithm is instrument-independent and circumvents fundamental cloud detection pitfalls. The database contains over 73,000 (36,000) polar vortex-region profiles in the Antarctic (Arctic) and over 21,000 (2000) PSC observations. An introductory climatology of Unified "background'' extinction is presented. It is seen that volcanic effects dominate the evolution of outside-vortex background extinctions, but perturbations apparently not related to volcanoes are seen as well. Interannual variations of background extinction fsinside the austral vortex are seen to be nearly decoupled from volcanic effects, while in the Arctic, inside-vortex extinctions show a considerable volcanic influence. An analysis of long-term PSC sighting is presented. Midwinter (July and January) PSC and clear-sky measurements at 20 km, in a fixed temperature range, are used for computing PSC probability. The grand average PSC probability calculated this way is nearly identical between hemispheres. In the Antarctic the interannual PSC probability pattern is distinctly cyclic but is convoluted by volcanic perturbations in background aerosol. In the Arctic the PSC probability has much less temporal coherence than in the Antarctic but is similarly impacted by volcanic background increases. An explanation for the variation in PSC probabilities, in terms of interannual differences in denitrification, is discussed. Finally, a statistical analysis of tropopause height in relation to PSC formation is also presented. PSC observations are seen to be strongly associated with elevated tropopause heights, indicating that tropospheric, synoptic-scale flow perturbations are the primary forcing mechanism for Arctic PSC formation, as evidenced in this long-term satellite record. C1 Computat Phys Inc, Springfield, VA 22151 USA. NASA, Langley Res Ctr, Hampton, VA 23665 USA. RP Fromm, M (reprint author), Computat Phys Inc, 1801 Braddock Rd,Suite 210, Springfield, VA 22151 USA. EM mike.fromm@nrl.navy.mil; alfred@cpi.com; Michael.C.Pitts@nasa.gov RI Fromm, Michael/F-4639-2010 NR 52 TC 34 Z9 34 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 JUN 26 PY 2003 VL 108 IS D12 AR 4366 DI 10.1029/2002JD002772 PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 708QA UT WOS:000184578400002 ER PT J AU Randall, CE Rusch, DW Bevilacqua, RM Hoppel, KW Lumpe, JD Shettle, E Thompson, E Deaver, L Zawodny, J Kyro, E Johnson, B Kelder, H Dorokhov, VM Konig-Langlo, G Gil, M AF Randall, CE Rusch, DW Bevilacqua, RM Hoppel, KW Lumpe, JD Shettle, E Thompson, E Deaver, L Zawodny, J Kyro, E Johnson, B Kelder, H Dorokhov, VM Konig-Langlo, G Gil, M TI Validation of POAM III ozone: Comparisons with ozonesonde and satellite data SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE ozone; validation; POAM; solar occultation; SAGE; HALOE ID HALOGEN OCCULTATION EXPERIMENT; STRATOSPHERIC AEROSOL; SAGE-II; POLAR OZONE; LOWERMOST STRATOSPHERE; UPPER TROPOSPHERE; ATMOS EXPERIMENT; PROFILES; VARIABILITY; INSTRUMENT AB This paper describes the validation of ozone profiles from the Polar Ozone and Aerosol Measurement (POAM) III instrument. POAM III O-3 is measured with 1-km vertical resolution throughout most of the stratosphere and random errors of similar to5%. It is shown that sunspots do not significantly affect the POAM O-3 retrievals, nor do polar stratospheric clouds, except under rarely encountered, extreme conditions of very low O-3 and exceptionally high aerosol extinction. A statistical analysis is presented of comparisons between coincident measurements from POAM III and ozonesondes, the Halogen Occultation Experiment (HALOE) and the Stratospheric Aerosol and Gas Experiment (SAGE) II. On average, POAM III O-3 profiles agree to within +/-5% with these correlative data from 13 to 60 km. There is a suggestion that from 30 to 60 km POAM III sunrise data might be biased slightly low (<5%) relative to POAM sunset data. There is evidence that POAM III has a high bias of up to similar to 0.1 ppmv from 10 to 12 km, and that this bias might stem, in part, from errors in the retrieval of aerosol extinction at 0.6 mm, the primary O-3 absorption wavelength in the POAM retrievals. Below 10 km the POAM III data agree with coincident sonde measurements to better than 0.05 ppmv on average, which can correspond to large relative differences of more than +30% at 8-9 km and -100% at 5 km. We conclude that the POAM III profiles are highly accurate and adequate for quantitative scientific studies. C1 Univ Colorado, Atmospher & Space Phys Lab, Boulder, CO 80309 USA. USN, Res Lab, Washington, DC 20375 USA. Computat Phys Inc, Springfield, VA USA. GATS Inc, Newport News, VA USA. NASA, Langley Res Ctr, Hampton, VA 23665 USA. Finnish Meteorol Inst, Spdankyla Observ, Sodankyla, Finland. NOAA CMDL, Boulder, CO USA. Royal Netherlands Meteorol Inst, KNMI, De Bilt, Netherlands. Cent Aerol Observ, Moscow, Russia. Alfred Wegener Inst Polar & Marine Res, Bremerhaven, Germany. Inst Nacl Tecn Aeroespacial, LATMOS, Torrejon De Arroz, Spain. RP Randall, CE (reprint author), Univ Colorado, Atmospher & Space Phys Lab, Campus Box 392, Boulder, CO 80309 USA. EM randall@lasp.colorado.edu; rusch@lasp.colorado.edu; bevilacqua@nrl.navy.mil; karl.hoppel@nrl.navy.mil; lumpe@cpi.com; shettle@nrl.navy.mil; r.e.thompson@larc.nasa.gov; l.e.deaver@larc.nasa.gov; j.m.zawodny@larc.nasa.gov; esko.kyro@fmi.fi; Bryan.Johnson@noaa.gov; Hennie.Kelder@knmi.nl; vdor@caomsk.mipt.ru; gkoenig@awi-bremerhaven.de; gilm@inta.es RI Konig-Langlo, Gert/K-5048-2012; Randall, Cora/L-8760-2014 OI Konig-Langlo, Gert/0000-0002-6100-4107; Randall, Cora/0000-0002-4313-4397 NR 32 TC 59 Z9 60 U1 1 U2 3 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 JUN 26 PY 2003 VL 108 IS D12 AR 4367 DI 10.1029/2002JD002944 PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 708QA UT WOS:000184578400003 ER PT J AU DiSanti, MA Mumma, MJ Dello Russo, N Magee-Sauer, K Griep, DM AF DiSanti, MA Mumma, MJ Dello Russo, N Magee-Sauer, K Griep, DM TI Evidence for a dominant native source of carbon monoxide in Comet C/1996 B2 (Hyakutake) SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article DE comets; ices; infrared spectroscopy; carbon monoxide ID O1 HALE-BOPP; B2 HYAKUTAKE; HYDROGEN-CYANIDE; CO; WATER; IDENTIFICATION; SPECTROSCOPY; ATMOSPHERES; EXCITATION; TELESCOPE AB Carbon monoxide was measured in C/1996 B2 (Hyakutake) on four preperihelion dates, UT 1996 March 24.5 and April 10.2-12.2, using CSHELL at the NASA Infrared Telescope Facility on Mauna Kea, Hawaii. These observations provided the first secure ground-based detection of cometary CO at infrared wavelengths. The rotational temperatures retrieved for CO are consistent with a heliocentric dependence T-rot = 63 R-h(-1.06) K over the range R-h = 1.06-0.64 AU. From long-slit analysis we distinguish native and distributed sources of CO, and we infer the relative abundance of native to total CO to be 0.773 +/- 0.054 on April 12.2. If this ratio is constant on UT April 11.2 and 12.2, the mean mixing ratios ( relative to water) are 0.149 +/- 0.019 for native CO and 0.191 +/- 0.022 for the sum of native and extended sources. These mixing ratios are based on direct measurements of H2O made on the same dates with the same instrument and analyzed with the same data processing algorithms. The observed spatial scale for complete development of the extended source on UT 1996 April 12.2 was consistent with that observed for C/1995 O1 (Hale-Bopp) on UT 1997 January 21, after taking into account differences in outflow velocity and heliocentric distance assuming insolation-limited release. This may suggest similar progenitor material in these two comets. C1 NASA, Goddard Space Flight Ctr, Planetary Syst Branch, Greenbelt, MD 20771 USA. Catholic Univ Amer, Dept Phys, Washington, DC 20064 USA. Univ Hawaii, Infrared Telescope Facil, Hilo, HI USA. Rowan Univ, Dept Chem & Phys, Glassboro, NJ USA. RP DiSanti, MA (reprint author), NASA, Goddard Space Flight Ctr, Planetary Syst Branch, Code 693, Greenbelt, MD 20771 USA. RI mumma, michael/I-2764-2013; Magee-Sauer, Karen/K-6061-2015; Dello Russo, Neil/G-2727-2015 OI Magee-Sauer, Karen/0000-0002-4979-9875; Dello Russo, Neil/0000-0002-8379-7304 NR 44 TC 19 Z9 19 U1 0 U2 3 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 JUN 26 PY 2003 VL 108 IS E6 AR 5061 DI 10.1029/2002JE001961 PG 19 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 708VT UT WOS:000184591100001 ER PT J AU Huang, CS Reeves, GD Borovsky, JE Skoug, RM Pu, ZY Le, G AF Huang, CS Reeves, GD Borovsky, JE Skoug, RM Pu, ZY Le, G TI Periodic magnetospheric substorms and their relationship with solar wind variations SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article DE magnetic storm; substorm; periodic substorm; sawtooth injection; solar wind triggering ID INTERPLANETARY MAGNETIC-FIELD; EARTHS MAGNETOSPHERE; MAGNETOPAUSE CROSSINGS; CURRENT DISRUPTION; TAIL RECONNECTION; EXPANSION ONSET; INSTABILITY; PASSAGE; MODELS; CLOUD AB [1] Outstanding problems in magnetospheric substorms include what causes substorm onsets and whether substorms have some specific periodicity. This paper provides observations and interpretations that relate to these problems. We study a specific type of geosynchronous particle injections during magnetic storms and the possible relationship between the solar wind and injections. Three storm events are analyzed: the March - April 2001, October 2000, and September 1998 storms. During the main phase or initial recovery phase of the storms, recurrent particle injections with a period of 2 - 3 hours were observed by geosynchronous satellites. The particle fluxes exhibited a well-defined "sawtooth'' profile with gradual decreases ( flux dropouts) followed by rapid increases ( injections). The sawtooth injections coincided well with AE increases and are interpreted as the signature of periodic substorms. In one case, sawtooth substorm injections were correlated with continuous solar wind pressure oscillations. In two other cases, sawtooth substorm injections occurred after a solar wind pressure impulse arrived at the magnetosphere. The observations show that substorms during storm times can be indeed periodic with a period of 2 - 3 hours and that solar wind variations may trigger the periodic substorms. We suggest that magnetospheric substorms have an intrinsic cycle time of 2 - 3 hours. If solar wind pressure oscillations with periods comparable to the substorm cycle time are imposed on the magnetosphere, some magnetospheric resonant state may be excited, and periodic substorms can be triggered. Otherwise, if the solar wind oscillates too fast, not enough energy is accumulated in the magnetotail for substorms to occur; if the period of solar wind pressure oscillations is too long, magnetospheric energy may be released through other processes including internally triggered substorms. C1 MIT, Haystack Observ, Westford, MA 01886 USA. Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Peking Univ, Dept Geophys, Beijing 100871, Peoples R China. NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. RP Huang, CS (reprint author), MIT, Haystack Observ, Route 40, Westford, MA 01886 USA. RI Le, Guan/C-9524-2012; Reeves, Geoffrey/E-8101-2011 OI Le, Guan/0000-0002-9504-5214; Reeves, Geoffrey/0000-0002-7985-8098 NR 33 TC 55 Z9 56 U1 1 U2 7 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 JUN 26 PY 2003 VL 108 IS A6 AR 1255 DI 10.1029/2002JA009704 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 708WL UT WOS:000184593000006 ER PT J AU Niederhaus, CE Jacobs, JW AF Niederhaus, CE Jacobs, JW TI Experimental study of the Richtmyer-Meshkov instability of incompressible fluids SO JOURNAL OF FLUID MECHANICS LA English DT Article ID INERTIAL CONFINEMENT FUSION; RAYLEIGH-TAYLOR; SINGLE-MODE; INITIAL PERTURBATIONS; GAS INTERFACE; DRIVEN; GROWTH; LAYER; ACCELERATION; DEPENDENCE AB The Richtmyer-Meshkov instability of a low-Atwood-number miscible two-liquid system is investigated experimentally. The initially stratified fluids are contained within a rectangular tank mounted on a sled that rides on a vertical set of rails. The instability is generated by dropping the sled onto a coil spring, producing a nearly impulsive upward acceleration. The subsequent free-fall that occurs as the container travels upward and then downward on the rails allows the instability to evolve in the absence of gravity. The interface separating the two liquids initially has a well-defined sinusoidal perturbation that quickly inverts and then grows in amplitude after undergoing the impulsive acceleration. Disturbance amplitudes are measured and compared to theoretical predictions. Linear stability theory gives excellent agreement with the measured initial growth rate, a overdot(0), for single-mode perturbations with the predicted amplitudes differing by less than 10% from experimental measurements up to a non-dimensional time kaoverdot(0)t = 0.7, where k is the wavenumber. Linear stability theory also provides excellent agreement for the individual mode amplitudes of multi-mode initial perturbations until the interface becomes multi-valued. Comparison with previously published weakly nonlinear single-mode models shows good agreement up to kaoverdot(0)t = 3, whereas published nonlinear single-mode models provide good agreement up to kaoverdot(0)t = 30. The effects of Reynolds number on the vortex core evolution and overall growth rate of the interface are also investigated. Measurements of the overall amplitude are found to be unaffected by the Reynolds number for the range of values studied here. However, experiments carried out at lower values of Reynolds numbers were found to have decreased vortex core rotation rates. In addition, an instability in the vortex cores is observed. The time of appearance of this instability was found to increase when the Reynolds number is decreased. C1 Univ Arizona, Dept Aerosp & Mech Engn, Tucson, AZ 85721 USA. RP Niederhaus, CE (reprint author), NASA, Glenn Res Ctr, 21000 Brookpk Rd, Cleveland, OH 44135 USA. RI Jacobs, Jeffrey/B-1339-2013 OI Jacobs, Jeffrey/0000-0003-0193-7105 NR 41 TC 33 Z9 35 U1 0 U2 14 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 40 WEST 20TH ST, NEW YORK, NY 10011-4221 USA SN 0022-1120 J9 J FLUID MECH JI J. Fluid Mech. PD JUN 25 PY 2003 VL 485 BP 243 EP 277 DI 10.1017/S002211200300452X PG 35 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA 699LR UT WOS:000184058800012 ER PT J AU Tabazadeh, A AF Tabazadeh, A TI Commentary on "Homogeneous nucleation of NAD and NAT in liquid stratospheric aerosols: insufficient to explain denitrification" by Knopf et al. SO ATMOSPHERIC CHEMISTRY AND PHYSICS LA English DT Editorial Material ID SULFURIC-ACID; NITRIC-ACID; SURFACE; DROPLETS; PARTICLES; CRYSTALLIZATION; CLOUDS; WATER C1 NASA, Ames Res Ctr, Div Earth Sci, Moffett Field, CA 94035 USA. RP Tabazadeh, A (reprint author), NASA, Ames Res Ctr, Div Earth Sci, Moffett Field, CA 94035 USA. NR 13 TC 12 Z9 12 U1 0 U2 1 PU EUROPEAN GEOPHYSICAL SOC PI KATLENBURG-LINDAU PA MAX-PLANCK-STR 13, 37191 KATLENBURG-LINDAU, GERMANY SN 1680-7324 J9 ATMOS CHEM PHYS JI Atmos. Chem. Phys. PD JUN 24 PY 2003 VL 3 BP 863 EP 865 PG 3 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 696FN UT WOS:000183876500001 ER PT J AU Thomason, LW Taha, G AF Thomason, LW Taha, G TI SAGE III aerosol extinction measurements: Initial results SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article AB Beginning in February 2002, the Stratospheric Aerosol and Gas Experiment III (SAGE III) has been producing aerosol extinction profiles in the upper troposphere and stratosphere at nine wavelengths between 384 and 1545 nm. An initial examination of the data quality has found that the data agree well with coincident measurements by SAGE II and the shape of the aerosol spectra suggests that the measurement ensemble is consistent across most wavelengths. A problem, probably associated with ozone cross sections, creates small bias at 755 nm and possibly 869 nm. The channel at 601 nm is noisy due to strong ozone absorption and is produced mostly as a tool for tracking ozone data quality. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. Univ Arizona, Tucson, AZ USA. RP Thomason, LW (reprint author), NASA, Langley Res Ctr, Mail Stop 475, Hampton, VA 23681 USA. NR 8 TC 5 Z9 5 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 JUN 24 PY 2003 VL 30 IS 12 AR 1631 DI 10.1029/2003GL017317 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 698KV UT WOS:000183999500002 ER PT J AU Huang, FT Reber, CA AF Huang, FT Reber, CA TI Seasonal behavior of the semidiurnal and diurnal tides, and mean flows at 95 km, based on measurements from the High Resolution Doppler Imager (HRDI) on the Upper Atmosphere Research Satellite (UARS) SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE atmospheric/mesospheric tides; atmospheric/mesospheric mean flows; Upper Atmosphere Research Satellite (UARS)/HRDI ID WIND IMAGING INTERFEROMETER; GENERAL-CIRCULATION MODEL; NUMERICAL SPECTRAL MODEL; WAVE MOMENTUM DEPOSITION; LONG-TERM VARIABILITY; LARGE-SCALE DYNAMICS; GRAVITY-WAVE; MIDDLE ATMOSPHERE; SPREAD PARAMETERIZATION; LOWER THERMOSPHERE AB [1] Derived results from the High Resolution Doppler Imager (HRDI) on UARS have provided an enormous amount of new and invaluable information, including insight into the large global seasonal variability of atmospheric tides. These and other results have given added impetus to theoretical modeling efforts, including a focus on wave-wave and wave-mean-flow interactions and the resulting momentum and energy exchanges. We have extended previous analyses, and provide new results for HRDI data at 95 km using an algorithm that simultaneously generates the diurnal and semidiurnal tidal variations and the mean flows. The diurnal variations with season are quite different from those of the semidiurnal components, showing evidence of possible strong damping around the solstices, especially in the meridional winds. The mean zonal winds are eastward at equatorial latitudes, while the annual component of the mean meridional wind generally flows from the summer to the winter hemisphere. We compare our results with earlier results from HRDI and from selected models. C1 Sci Syst & Applicat Inc, Lanham, MD 20706 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Huang, FT (reprint author), Sci Syst & Applicat Inc, 10210 Greenbelt Rd,Suite 600, Lanham, MD 20706 USA. EM fthhx@aol.com; carl.a.reber@nasa.gov NR 42 TC 27 Z9 29 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 JUN 24 PY 2003 VL 108 IS D12 AR 4360 DI 10.1029/2002JD003189 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 698KX UT WOS:000183999700003 ER PT J AU Schwid, SR Petrie, MD Murray, R Leitch, J Bowen, J Alquist, A Pelligrino, R Roberts, A Harper-Bennie, J Milan, MD Luna, B Montgomery, L Lamparter, R Ku, YT Lee, H Goldwater, D Cutter, G Webbon, B AF Schwid, SR Petrie, MD Murray, R Leitch, J Bowen, J Alquist, A Pelligrino, R Roberts, A Harper-Bennie, J Milan, MD Luna, B Montgomery, L Lamparter, R Ku, YT Lee, H Goldwater, D Cutter, G Webbon, B CA NASA MS Cooling Study Grp TI A randomized controlled study of the acute and chronic effects of cooling therapy for MS SO NEUROLOGY LA English DT Article ID MULTIPLE-SCLEROSIS; BODY-TEMPERATURE; CONDUCTION; PROGRESSION; IMPROVEMENT; FATIGUE; SUIT AB Background: Cooling demyelinated nerves can reduce conduction block, potentially improving symptoms of MS. The therapeutic effects of cooling in patients with MS have not been convincingly demonstrated because prior studies were limited by uncontrolled designs, unblinded evaluations, reliance on subjective outcome measures, and small sample sizes. Objective: To determine the effects of a single acute dose of cooling therapy using objective measures of neurologic function in a controlled, double- blinded setting, and to determine whether effects are sustained during daily cooling garment use. Methods: Patients ( n = 84) with definite MS, mild to moderate disability ( Expanded Disability Status Scale score < 6.0), and self- reported heat sensitivity were randomized into a multicenter, sham- treatment controlled, doubleblind crossover study. Patients had the MS Functional Composite ( MSFC) and measures of visual acuity/ contrast sensitivity assessed before and after high- dose or low- dose cooling for 1 hour with a liquid cooling garment. One week later, patients had identical assessments before and after the alternate treatment. Patients were then re- randomized to use the cooling garment 1 hour each day for a month or to have observation only. They completed self- rated assessments of fatigue, strength, and cognition during this time, and underwent another acute cooling session at the end of the period. After 1 week of rest, they had identical assessments during the alternate treatment. Results: Body temperature declined during both high- dose and low- dose cooling, but high- dose produced a greater reduction ( p < 0.0001). High- dose cooling produced a small improvement in the MSFC (0.076 +/- 0.66, p = 0.007), whereas low- dose cooling produced only a trend toward improvement ( 0.053 +/- 0.031, p = 0.09), but the difference between conditions was not significant. Timed gait testing and visual acuity/ contrast sensitivity improved in both conditions as well. When patients underwent acute cooling following a month of daily cooling, treatment effects were similar. Patients reported less fatigue during the month of daily cooling, concurrently on the Rochester Fatigue Diary and retrospectively on the Modified Fatigue Impact Scale. Conclusions: Cooling therapy was associated with objectively measurable but modest improvements in motor and visual function as well as persistent subjective benefits. C1 Univ Rochester, Dept Neurol, Rochester, NY 14642 USA. Rocky Mt MS Ctr, Englewood, CO USA. Univ Washington, Seattle, WA 98195 USA. MS Assoc Amer, Hot Springs, AR USA. Ctr Neurodiagnost Res, San Jose, CA USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. AMC Canc Res Ctr, Denver, CO USA. RP Schwid, SR (reprint author), Univ Rochester, Dept Neurol, 601 Elmwood Ave,Box 605, Rochester, NY 14642 USA. FU NCRR NIH HHS [M01-RR00044] NR 27 TC 65 Z9 66 U1 1 U2 9 PU LIPPINCOTT WILLIAMS & WILKINS PI PHILADELPHIA PA 530 WALNUT ST, PHILADELPHIA, PA 19106-3621 USA SN 0028-3878 J9 NEUROLOGY JI Neurology PD JUN 24 PY 2003 VL 60 IS 12 BP 1955 EP 1960 PG 6 WC Clinical Neurology SC Neurosciences & Neurology GA 693CF UT WOS:000183696500014 PM 12821739 ER PT J AU French, AN Schmugge, TJ Kustas, WP Brubaker, KL Prueger, J AF French, AN Schmugge, TJ Kustas, WP Brubaker, KL Prueger, J TI Surface energy fluxes over El Reno, Oklahoma, using high-resolution remotely sensed data SO WATER RESOURCES RESEARCH LA English DT Article DE surface energy flux; thermal infrared; TIMS; El Reno; Oklahoma; SGP97; two source energy balance model ID SENSIBLE HEAT-FLUX; VEGETATION INDEXES; EARTHS SURFACE; VAPOR TRANSFER; TEMPERATURE; BALANCE; SOIL; EVAPORATION; CANOPY; RADIATION AB Accurate estimation of spatial distributions of evapotranspiration (ET) is a goal sought by hydrologists, agronomists, and meteorologists but is difficult to achieve. The usual approaches to estimating ET employ remote sensing observations and a surface energy flux model. However, resolution of remote sensing data, needed to observe patterns of biophysical variables, is commonly too coarse (>1 km) to distinguish between land cover types that constrain ET. Accuracy of ET estimates can be improved by using higher-resolution (<100 m) remote sensing data since they can distinguish clusters of vegetation from bare soil fields and water bodies. A demonstration of this potential is shown using aircraft-based remote sensing observations over a study site at El Reno, Oklahoma. Five midday surveys, conducted from 29 June to 2 July 1997, as part of the Southern Great Plains 1997 Experiment (SGP97), collected 12 m resolution images in the visible, near infrared, and thermal infrared. Surface temperature and vegetation density maps, created from these surveys, were combined with surface micrometeorological observations and with a two source energy balance model. Results from El Reno show that flux estimates with respect to ground-based eddy covariance observations can be accurate to within 40-80 W m(-2). This means that the high spatial resolution observations can potentially produce ET estimates similar in quality to ground-based point measurements. Additional work, needed to show how high-resolution remote sensing estimates can be related to coarser resolution observations, is underway using the satellite sensors ASTER (15-90 m resolution) and MODIS (250 m to 1 km resolution). C1 NASA, Hydrol Sci Branch, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. ARS, Hydrol & Remote Sensing Lab, USDA, Beltsville, MD 20705 USA. Univ Maryland, Dept Civil & Environm Engn, College Pk, MD 20742 USA. ARS, Natl Soil Tilth Lab, USDA, Ames, IA 50011 USA. RP French, AN (reprint author), NASA, Hydrol Sci Branch, Goddard Space Flight Ctr, Code 974, Greenbelt, MD 20771 USA. RI French, Andrew/M-4734-2014 OI French, Andrew/0000-0002-4018-1817 NR 49 TC 39 Z9 39 U1 1 U2 6 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0043-1397 J9 WATER RESOUR RES JI Water Resour. Res. PD JUN 24 PY 2003 VL 39 IS 6 AR 1164 DI 10.1029/2002WR001734 PG 12 WC Environmental Sciences; Limnology; Water Resources SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Water Resources GA 698LR UT WOS:000184001500002 ER PT J AU Seo, JT Yang, Q Creekmore, S Tabibi, B Temple, D Kim, SY Yoo, K Mott, A Namkung, M Jung, SS AF Seo, JT Yang, Q Creekmore, S Tabibi, B Temple, D Kim, SY Yoo, K Mott, A Namkung, M Jung, SS TI Large pure refractive nonlinearity of nanostructure silica aerogel SO APPLIED PHYSICS LETTERS LA English DT Article ID Z-SCAN; NANOPARTICLES AB The nonlinear refraction coefficient of silica aerogel was estimated to be similar to-1.5 x 10(-15) m(2)/W (similar to -3.67 x 10(-9) esu) with a signal-beam z-scan spectroscopy. The third-order nonlinear refraction coefficient of nanostructure silica aerogel was almost five orders larger than the nonlinear refraction (chi(3)) of bulk material. The large nonlinear refraction with high nonlinear figure of merit is an ideal optical property for nonlinear optical applications. (C) 2003 American Institute of Physics. C1 Hampton Univ, Dept Phys, Hampton, VA 23668 USA. Sogang Univ, Dept Chem Engn, Seoul 121742, South Korea. USA, Res Lab, Adelphi, MD 20783 USA. NASA, Langley Res Ctr, Nondestruct Evaluat Sci Branch, Hampton, VA 23681 USA. Korea Res Inst Stand & Sci, Taejon 305600, South Korea. RP Seo, JT (reprint author), Hampton Univ, Dept Phys, Hampton, VA 23668 USA. RI Namkung, Min/E-1533-2012 NR 12 TC 21 Z9 23 U1 0 U2 6 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 JUN 23 PY 2003 VL 82 IS 25 BP 4444 EP 4446 DI 10.1063/1.1585127 PG 3 WC Physics, Applied SC Physics GA 690PK UT WOS:000183557300012 ER PT J AU von Allmen, P Sadler, DJ Jensen, C Ostrom, NP McCain, ST Vojak, BA Eden, JG AF von Allmen, P Sadler, DJ Jensen, C Ostrom, NP McCain, ST Vojak, BA Eden, JG TI Linear, segmented microdischarge array with an active length of similar to 1 cm: cw and pulsed operation in the rare gases and evidence of gain on the 460.30 nm transition of Xe+ SO APPLIED PHYSICS LETTERS LA English DT Article ID LASER OSCILLATION; XENON AB A linear, segmented channel, microdischarge array having an similar to80 x 380 mum(2) aperture and an active length of similar to1 cm, has been fabricated in a ceramic multilayer structure and characterized in Ne, Ar, and Xe. The length of this seven-section device is more than an order of magnitude larger than those for previous arrays (2-3 elements) of coaxial microdischarge devices, and the discharge segments are individually ballasted with integrated thick-film resistors. Pulsed and cw operation of the array for Xe pressures as large as 700 Torr has been demonstrated and experimental indications of gain on the Xe+ 6p D-4(3/2)0 --> 6s P-4(3/2) transition at 460.30 nm are presented. This device is well suited for the excitation of microlasers, either by electron impact pumping of gases and vapors, or by photoexcitation of solid state lasers in a slab geometry. (C) 2003 American Institute of Physics. C1 Motorola Labs, Solid State Res Ctr, Tempe, AZ 85284 USA. Univ Illinois, Dept Elect & Comp Engn, Lab Opt Phys & Engn, Urbana, IL 61801 USA. RP von Allmen, P (reprint author), CALTECH, Jet Prop Lab, NASA, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 10 TC 23 Z9 23 U1 1 U2 6 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 JUN 23 PY 2003 VL 82 IS 25 BP 4447 EP 4449 DI 10.1063/1.1585137 PG 3 WC Physics, Applied SC Physics GA 690PK UT WOS:000183557300013 ER PT J AU Zak, M Kulikov, I AF Zak, M Kulikov, I TI Soliton resonance in Bose-Einstein condensate SO PHYSICS LETTERS A LA English DT Article AB A new phenomenon in nonlinear dispersive systems, including a Bose-Einstein condensate (BEC), has been described. It is based upon a resonance between an externally induced soliton and "eigen-solitons" of the homogeneous cubic Schrodinger equation. There have been shown that a moving source of positive/negative potential induces bright/dark solitons in an attractive/repulsive Bose condensate. (C) 2003 Elsevier Science B.V. All rights reserved. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Zak, M (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 2 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-9601 J9 PHYS LETT A JI Phys. Lett. A PD JUN 23 PY 2003 VL 313 IS 1-2 BP 89 EP 92 DI 10.1016/S0375-9601(03)00725-4 PG 4 WC Physics, Multidisciplinary SC Physics GA 693AJ UT WOS:000183692200013 ER PT J AU Di Girolamo, P Demoz, BB Whiteman, DN AF Di Girolamo, P Demoz, BB Whiteman, DN TI Model simulations of melting hydrometeors: A new lidar bright band from melting frozen drops SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID RAINDROP SIZE DISTRIBUTION; RADAR; ICE; SPHERES; WATER AB [1] This study provides a model simulation of lidar and radar echoes from melting frozen drops. Results are based on a concentric-sphere Mie scattering code, together with a melting layer model. Simulations reveal the appearance of a lidar bright band in the melting layer, as well as a fainter radar bright band. Both maxima are located approximately 300 m below the freezing level for a core/shell radius of 0.7. In order to achieve a more realistic representation of the melting process, preliminary simulations have also been obtained from an eccentric sphere Mie scattering code that are in general agreement with results obtained with the concentric sphere code. The sensitivity of the algorithms to changes in initial conditions is investigated. C1 Univ Basilicata, DIFA, I-85100 Potenza, Italy. NASA, Goddard Space Flight Ctr, Mesoscale Atmospher Proc Branch, Greenbelt, MD 20771 USA. RP Di Girolamo, P (reprint author), Univ Basilicata, DIFA, I-85100 Potenza, Italy. RI Demoz, Belay/N-4130-2014 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 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUN 21 PY 2003 VL 30 IS 12 AR 1626 DI 10.1029/2002GL016825 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 693XH UT WOS:000183743300002 ER PT J AU Spaun, NA Pappalardo, RT Head, JW AF Spaun, NA Pappalardo, RT Head, JW TI Evidence for shear failure in forming near-equatorial lineae on Europa SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article DE icy satellites; Jovian satellites; Europa; surface geology; tidal stresses; tectonic processes ID STRIKE-SLIP FAULTS; STATE IMAGING DATA; TIDAL STRESSES; NONSYNCHRONOUS ROTATION; GEOLOGICAL EVIDENCE; SUBSURFACE OCEAN; POLAR WANDER; ICE SHELL; PATTERNS; FEATURES AB [1] Global stress models for Europa are unable to readily explain the orientations of lineae in the equatorial region of Europa's trailing hemisphere if lineae originate as tension cracks. Our analysis of two equatorial, trailing regions reveals that lineae are predominantly oriented NE and NW, and E-W lineae are rare, contrary to predictions of stress and formation models. The measured orientations are consistent with an origin by shear failure. The studied regions are located near the point of maximum differential stress and minimum surface tensile stresses, where shear faulting may surmount tension fracturing. Several types of lineae are recognized; their relative abundance is inferred to have changed with time, consistent with formation models suggesting lineae evolve from simple troughs to complex ridges. The opening of crevasse- like tensile fractures is not required for generation of all lineae; the observations are consistent with ridge formation models where troughs ( formed in tension or shear) experience shear heating from tidal deformation, allowing warm ice to buoyantly uplift, creating ridges. The stratigraphic relationships indicate the following: ridged plains formed first, followed by continued formation of a wide range of lineae, and lastly emplacement of lenticulae and continued linea formation. This sequence is consistent with an early thin, brittle lithosphere that thickened with time and was subject to repetitive diurnal tides during similar to30degrees-90degrees of nonsynchronous rotation. Ultimately, the thickened shell underwent thermally induced solid-state convection, producing lenticulae. The young surface age of Europa implies that this entire stratigraphic sequence was emplaced in the geologically recent past. C1 Brown Univ, Dept Geol Sci, Providence, RI 02912 USA. Univ Colorado, LASP, Astrophys & Planetary Sci Dept, Boulder, CO 80309 USA. RP Spaun, NA (reprint author), NASA, Ames Res Ctr, MS 245-3, Moffett Field, CA 94035 USA. NR 43 TC 11 Z9 11 U1 0 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 JUN 21 PY 2003 VL 108 IS E6 AR 5060 DI 10.1029/2001JE001499 PG 21 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 696HL UT WOS:000183881500001 ER PT J AU Keenan, FP Katsiyannis, AC Brosius, JW Davila, JM Thomas, RJ AF Keenan, FP Katsiyannis, AC Brosius, JW Davila, JM Thomas, RJ TI Emission lines of Na-like ions in spectra obtained with the Solar EUV Research Telescope and Spectrograph (SERTS) SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE atomic data; Sun : activity; Sun : flares; ultraviolet : general ID EXTREME-ULTRAVIOLET SPECTRA; ELECTRON-IMPACT EXCITATION; FE-XVI; ATOMIC DATABASE; ACTIVE-REGION; NI-XVIII; TRANSITIONS; SUN; INTENSITIES; STRENGTHS AB Theoretical emission-line ratios involving transitions in the 236-412 Angstrom wavelength range are presented for the Na-like ions Ar viii, Cr xiv, Mn xv, Fe xvi, Co xvii, Ni xviii and Zn xx. A comparison of these with an extensive data set of the solar active region, quiet-Sun, subflare and off-limb observations, obtained during rocket flights by the Solar EUV Research Telescope and Spectrograph (SERTS), reveals generally very good agreement between theory and experiment. This indicates that most of the Na-like ion lines are reliably detected in the SERTS observations, and hence may be employed with confidence in solar spectral analyses. However, the features in the SERTS spectra at 236.34 and 300.25 Angstrom, originally identified as the Ni xviii 3p (2) P-3/2 -3d (2) D-3/2 and Cr xiv 3p (2) P-3/2 -3d (2) D-5/2 transitions, respectively, are found to be due to emission lines of Ar xiii (236.34 Angstrom) and possibly S v or Ni vi (300.25 Angstrom). The Co xvii 3s (2) S-3p (2) P-3/2 line at 312.55 Angstrom is always badly blended with an Fe xv feature at the same wavelength, but Mn xv 3s (2) S-3p (2) P-1/2 at 384.75 Angstrom may not always be as affected by second-order emission from Fe xii 192.37 Angstrom as previously thought. On the other hand, we find that the Zn xx 3s (2) S-3p (2) P-3/2 transition can sometimes make a significant contribution to the Zn xx/Fe xiii 256.43- Angstrom blend, and hence care must be taken when using this feature as an Fe xiii electron density diagnostic. A line in the SERTS-89 active region spectrum at 265.00 Angstrom has been re-assessed, and we confirm its identification as the Fe xvi 3p (2) P-3/2 -3d (2) D-3/2 transition. C1 Queens Univ Belfast, Dept Pure & Appl Phys, Belfast BT7 1NN, Antrim, North Ireland. NASA, Astron & Solar Phys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Catholic Univ Amer, Dept Phys, Washington, DC 20064 USA. RP Keenan, FP (reprint author), Queens Univ Belfast, Dept Pure & Appl Phys, Belfast BT7 1NN, Antrim, North Ireland. RI Katsiyannis, Thanassis/L-8496-2013 NR 33 TC 7 Z9 8 U1 1 U2 1 PU BLACKWELL PUBLISHING LTD PI OXFORD PA 9600 GARSINGTON RD, OXFORD OX4 2DG, OXON, ENGLAND SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD JUN 21 PY 2003 VL 342 IS 2 BP 513 EP 518 DI 10.1046/j.1365-8711.2003.06559.x PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 690BC UT WOS:000183526600020 ER PT J AU Reichardt, S Reichardt, J AF Reichardt, S Reichardt, J TI Effect of multiple scattering on depolarization measurements with spaceborne lidars SO APPLIED OPTICS LA English DT Article ID CIRRUS CLOUD CLIMATOLOGY; MONTE-CARLO CALCULATIONS; HEXAGONAL ICE CRYSTALS; OPTICAL-PROPERTIES; BACKSCATTER LIDAR; INVERSION METHOD; RAMAN LIDAR; RETURNS; EXTINCTION; AEROSOL AB An analytical model based on the integration of the scattering-angle and light-path manifold has been developed to quantify the effect of multiple scattering on cirrus measurements obtained with elastic polarization lidars from space. Light scattering by molecules and by a horizontally homogeneous cloud is taken into account. Lidar parameters, including laser beam divergence, can be freely chosen. Up to 3 orders of scattering are calculated. Furthermore, an inversion technique for the retrieval of cloud extinction profiles from measurements with elastic-backscatter lidars is proposed that explicitly takes multiple scattering into account. It is found that for typical lidar system parameters such as those of the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) instrument multiple scattering does not significantly affect depolarization-ratio measurements in cirrus clouds with small to moderate optical depths. For all simulated clouds, the absolute value of the difference between measured and single-scattering volume depolarization ratio is <0.006. The particle depolarization ratio can be calculated from the measured volume depolarization ratio and the retrieved backscatter ratio without degradation of accuracy; thus characterization of the various cirrus categories in terms of the particle depolarization ratio and retrieval of cloud microphysical properties is feasible from space. The results of this study apply to polar stratospheric clouds as well. (C) 2003 Optical Society of America. C1 Univ Maryland Baltimore Cty, Joint Ctr Earth Syst Technol, Baltimore, MD 21250 USA. NASA, Goddard Space Flight Ctr, Atmospher Chem & Dynam Branch, Atmospheres Lab, Greenbelt, MD 20771 USA. RP Reichardt, S (reprint author), Univ Maryland Baltimore Cty, Joint Ctr Earth Syst Technol, 1000 Hilltop Circle, Baltimore, MD 21250 USA. EM sreichardt@aeolus.gsfc.nasa.gov; reichardt@code916.gsfc.nasa.gov NR 46 TC 11 Z9 11 U1 0 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 JUN 20 PY 2003 VL 42 IS 18 BP 3620 EP 3633 DI 10.1364/AO.42.003620 PG 14 WC Optics SC Optics GA 692LC UT WOS:000183661700026 PM 12833968 ER PT J AU Cottin, H Moore, MH Benilan, Y AF Cottin, H Moore, MH Benilan, Y TI Photodestruction of relevant interstellar molecules in ice mixtures SO ASTROPHYSICAL JOURNAL LA English DT Article DE astrochemistry; ISM : molecules; methods : laboratory; molecular processes; ultraviolet : ISM ID ORGANIC-MOLECULES; RADIATION-FIELD; UV PHOTOLYSIS; ULTRAVIOLET; ANALOGS; CLOUDS; COMETARY; IRRADIATION; PROTOSTARS; CHEMISTRY AB UV photodestruction of some interstellar molecules is studied in different kinds of ices. CH4, CH3OH, NH3, CO2, CO, and HNCO are photolyzed as pure ices, or mixed with water or molecular nitrogen, at about 10 K. The destruction cross sections of these molecules are estimated for use in photochemical models of interstellar ices. We show that the destruction rate depends on the ice in which the studied compound is embedded. C1 Univ Paris 07, Lab Interuniv Syst Atmpospher, Creteil, France. Univ Paris 12, Lab Interuniv Syst Atmpospher, Creteil, France. NASA, Goddard Space Flight Ctr, Astrochem Branch, Greenbelt, MD 20771 USA. RP Univ Paris 07, Lab Interuniv Syst Atmpospher, Creteil, France. EM cottin@lisa.univ-paris12.fr; marla.h.moore@nasa.gov; benilan@lisa.univ-paris12.fr RI Cottin, Herve/H-5654-2013 OI Cottin, Herve/0000-0001-9170-5265 NR 36 TC 97 Z9 97 U1 2 U2 15 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 JUN 20 PY 2003 VL 590 IS 2 BP 874 EP 881 DI 10.1086/375149 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 688WA UT WOS:000183459200023 ER PT J AU Smale, AP Homan, J Kuulkers, E AF Smale, AP Homan, J Kuulkers, E TI The complete Z diagram of LMC X-2 SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; binaries : close; stars : individual (LMC X-2); stars : neutron; X-rays : stars ID QUASI-PERIODIC OSCILLATIONS; FAST-TIME VARIABILITY; SCO X-2 GX-349+2; X-RAY BINARIES; TIMING BEHAVIOR; CYGNUS X-2; Z-TRACK; DISCOVERY; GX-340+0; GX-17+2 AB We present results from four Rossi X-Ray Timing Explorer observations of the bright, low-mass X-ray binary LMC X-2. During these observations, which span 1 yr and include over 160 hr of data, the source exhibits clear evolution through three branches on its hardness-intensity and color-color diagrams, consistent with the flaring, normal, and horizontal branches (FB, NB, HB) of a Z source and remarkably similar to Z tracks derived for GX 17+ 2, Sco X-1, and GX 349+2. LMC X-2 was observed in the FB, NB, and HB for roughly 30%, 40%, and 30%, respectively, of the total time covered. The source traces out the full extent of the Z in similar to1 day, and the Z track shows evidence for secular shifts on a timescale in excess of a few days. Although the count rate of LMC X-2 is low compared with the other known Z sources due to its greater distance, the power density spectra selected by branch show very low frequency noise characteristics at least consistent with those from other Z sources. We thus confirm the identification of LMC X-2 as a Z source, the first identified outside our Galaxy. C1 NASA, Goddard Space Flight Ctr, Lab High Energy Astrophys, Greenbelt, MD 20771 USA. Osserv Astron Brera, I-23807 Merate, LC, Italy. ESA, ESTEC, Sci Operat & Data Syst Div, SCI SDG, NL-2201 AZ Noordwijk, Netherlands. RP Smale, AP (reprint author), NASA, Goddard Space Flight Ctr, Lab High Energy Astrophys, Code 660-1, Greenbelt, MD 20771 USA. NR 24 TC 14 Z9 14 U1 0 U2 1 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 JUN 20 PY 2003 VL 590 IS 2 BP 1035 EP 1040 DI 10.1086/375047 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 688WA UT WOS:000183459200036 ER PT J AU Nagata, S Hara, H Kano, R Kobayashi, K Sakao, T Shimizu, T Tsuneta, S Yoshida, T Gurman, JB AF Nagata, S Hara, H Kano, R Kobayashi, K Sakao, T Shimizu, T Tsuneta, S Yoshida, T Gurman, JB TI Spatial and temporal properties of hot and cool coronal loops SO ASTROPHYSICAL JOURNAL LA English DT Article DE Sun : activity; Sun : corona; Sun : X-rays, gamma rays ID XUV DOPPLER TELESCOPE; SOLAR ACTIVE REGIONS; X-RAY TELESCOPE; TRANSITION-REGION; TEMPERATURE STRUCTURE; MULTILAYER MIRRORS; QUIET-SUN; EMISSION; EXPLORER; TRACE AB A suite of images from the XUV Doppler Telescope (XDT), the Yohkoh Soft X-ray Telescope (SXT), and the Extreme-Ultraviolet Imaging Telescope (EIT) on the Solar and Heliospheric Observatory (SOHO) allow us to see the whole (T > 1 MK) temperature evolution of coronal loops. The detailed morphological comparison of an active region shows that hot loops seen in SXT (T > 3 MK) and cool loops seen in the the EIT 195 Angstrom band (T similar to 1.5 MK) are located in almost alternating manner. The anticoincidence of the hot and the cool loops is conserved for a duration much longer than the estimated cooling timescale. However, both hot and cool loops have counterparts in the intermediate-temperature images. The cross-correlation coefficients are higher for neighboring temperature pairs and lower for pairs with larger temperature differences. These results suggest that loops are not isothermal but rather have a differential emission measure distribution of modest but finite width that peaks at different temperatures for different loops. C1 Univ Tokyo, Sch Sci, Dept Astron, Bunkyo Ku, Tokyo 1130033, Japan. Natl Astron Observ, Tokyo 1818588, Japan. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Univ Tokyo, Sch Sci, Dept Astron, Bunkyo Ku, Tokyo 1130033, Japan. NR 43 TC 26 Z9 26 U1 0 U2 1 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 JUN 20 PY 2003 VL 590 IS 2 BP 1095 EP 1110 DI 10.1086/375127 PN 1 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 688WA UT WOS:000183459200042 ER PT J AU Doron, R Doschek, GA Laming, JM Feldman, U Bhatia, AK AF Doron, R Doschek, GA Laming, JM Feldman, U Bhatia, AK TI Temperature measurements in the solar transition region using NIII line intensity ratios SO ASTROPHYSICAL JOURNAL LA English DT Article DE atomic data; atomic processes; Sun : transition region; Sun : UV radiation; techniques : spectroscopic ID ELECTRON-IMPACT EXCITATION; BORON-LIKE IONS; RATE COEFFICIENTS; QUIET-SUN; SUMER TELESCOPE; CROSS-SECTIONS; CORONAL HOLES; N-III; O-IV; ULTRAVIOLET AB UV emission from B-like N and O ions offers a rather rare opportunity for recording spectral lines in a narrow wavelength range that can potentially be used to derive temperatures relevant to the solar transition region. In these ions, the line intensity ratios of the type (2s2p(2) - 2p(3))/(2s(2)2p - 2s2p2) are very sensitive to the electron temperature. In addition, the lines involving the ratios fall within a range of only similar to12Angstrom; in N III the lines fall in the 980 - 992 Angstrom range, and in O IV in the 780 - 791 Angstrom range. In this work, we explore the use of these atomic systems, primarily in N III, for temperature diagnostics of the transition region by analyzing UV spectra obtained by the Solar Ultraviolet Measurement of Emitted Radiation spectrometer. own on the Solar and Heliospheric Observatory. The N III temperature-sensitive line ratios are measured in more than 60 observations. The mean measured ratios are lower by similar to30% than those predicted in the typical quiet Sun. Assuming an isothermal plasma, most of the measured ratios correspond to temperatures in the range 5.7 x 10(4) - 6.7 x 10(4) K. This range is considerably lower than the calculated temperature of maximum abundance of N III, which is similar to7.6 x 10(4) K. Detailed analysis of the spectra further indicates that the measured ratios are probably somewhat overestimated because of resonant scattering effects in the 2s(2)2p - 2s2p(2) lines and small blends in the 2s2p(2)-2p(3) lines. Actual lower ratios would only increase the discrepancy between the ionization balance calculations and present temperature measurements based on a collisional excitation model. In the case of the O IV spectra, we determine that because of the close proximity in wavelength of the weak line (2s2p(2) - 2p(3) transitions) to a strong Ne vIII line, sufficiently accurate ratio measurements cannot be obtained. C1 USN, Res Lab, EO Hulburt Ctr Space Res, Washington, DC 20375 USA. George Mason Univ, Inst Computat Sci & Informat, Fairfax, VA 22030 USA. Artep Inc, Ellicott City, MD 21042 USA. NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. RP Doron, R (reprint author), USN, Res Lab, EO Hulburt Ctr Space Res, Code 7670,4555 Overlook Ave SW, Washington, DC 20375 USA. RI Doron, Ramy/I-2064-2013 NR 32 TC 2 Z9 2 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 JUN 20 PY 2003 VL 590 IS 2 BP 1121 EP 1130 DI 10.1086/375185 PN 1 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 688WA UT WOS:000183459200044 ER PT J AU Chiang, LY Naselsky, PD Verkhodanov, OV Way, MJ AF Chiang, LY Naselsky, PD Verkhodanov, OV Way, MJ TI Non-Gaussianity of the derived maps from the first-year Wilkinson Microwave Anisotropy Probe data SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmic microwave background; cosmology : observations; methods : data analysis ID STATISTICS; FIELDS AB We present non-Gaussianity testing on derived maps from the recently released first-year Wilkinson Microwave Anisotropy Probe data by Tegmark, de Oliveria-Costa, & Hamilton. Our test is based on a phase-mapping technique that has the advantage of testing non-Gaussianity at separate multipole bands. We show that their foreground-cleaned map is against the random-phase hypothesis at all four multipole bands centered around l = 150, 290, 400, and 500. Their Wiener- filtered map, on the other hand, is Gaussian for l < 250 and marginally Gaussian for 224 < l < 350. However, we see the evidence of non- Gaussianity for l > 350 as we detect certain degrees of phase coupling, hence against the random-phase hypothesis. Our phase-mapping technique is particularly useful for testing the accuracy of component separation methods. C1 Theoret Astrophys Ctr, DK-2100 Copenhagen, Denmark. Niels Bohr Inst Astron, DK-2100 Copenhagen, Denmark. Russian Acad Sci, Special Astrophys Observ, Nizhnii Arkhyz 369167, Russia. NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA. RP Chiang, LY (reprint author), Theoret Astrophys Ctr, Juliane Maries Vej 30, DK-2100 Copenhagen, Denmark. RI Way, Michael/D-5254-2012; OI Way, Michael/0000-0003-3728-0475 NR 11 TC 103 Z9 103 U1 0 U2 1 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 JUN 20 PY 2003 VL 590 IS 2 BP L65 EP L68 DI 10.1086/376822 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 688WE UT WOS:000183459600001 ER PT J AU Wang, J Yaqoob, T Szokoly, G Gilli, R Kewley, L Mainieri, V Nonino, M Rosati, P Tozzi, P Zheng, W Zirm, A Norman, C AF Wang, J Yaqoob, T Szokoly, G Gilli, R Kewley, L Mainieri, V Nonino, M Rosati, P Tozzi, P Zheng, W Zirm, A Norman, C TI A puzzling X-ray source found in the Chandra Deep Field-South SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : active; galaxies : individual (CXOCDFS J033225.3-274219) galaxies : peculiar; X-rays : galaxies ID ACTIVE GALACTIC NUCLEI; EMISSION-LINE; AFTERGLOW; NGC-6240; GALAXY; BURST AB In this Letter, we report the detection of an extremely strong X-ray emission line in the 940 ks Chandra ACIS-I spectrum of CXOCDFS J033225.3-274219. The source was identified as a type 1 active galactic nucleus at a redshift of z = 1.617, with a 2.0-10.0 keV rest-frame X-ray luminosity of similar to10(44) ergs s(-1). The emission line was detected at 6.2(-0.1)(+0.2) keV, with an equivalent width ( EW) of 4.4(-1.4)(+3.2) keV; both quantities refer to the observed frame. In the rest frame, the line is at 16.2(-0.3)(+0.4) keV with an EW of 11.5(-3.7)(+8.3) keV. An X-ray emission line at a similar energy(similar to17 keV, in the rest frame) in PKS 2149-306 was discovered before using ASCA data. We reject the possibility that the line is due to a statistical or instrumental artifact. The line is most likely due to blueshifted Fe K emission from an relativistic outflow, probably an inner X-ray jet, with velocities of the order of similar to0.6c-0.7c. Other possible explanations are also discussed. C1 Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. Max Planck Inst Extraterr Phys, D-85741 Garching, Germany. Ist Nazl Fis Nucl, Osservatorio Astrofis Arcetri, I-50125 Florence, Italy. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. European So Observ, D-85748 Garching, Germany. Ist Nazl Astrofis, Osservatorio Astron, I-34131 Trieste, Italy. Space Telescope Sci Inst, Baltimore, MD 21218 USA. RP Wang, J (reprint author), Johns Hopkins Univ, Dept Phys & Astron, 3400 N Charles St, Baltimore, MD 21218 USA. RI Gilli, Roberto/P-1110-2015 OI Gilli, Roberto/0000-0001-8121-6177 NR 20 TC 12 Z9 12 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 JUN 20 PY 2003 VL 590 IS 2 BP L87 EP L90 DI 10.1086/376821 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 688WE UT WOS:000183459600006 ER PT J AU Urquhart, ML Gulick, VC AF Urquhart, ML Gulick, VC TI Plausibility of the "White Mars" hypothesis based upon the thermal nature of the Martian subsurface SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID HEAT-FLOW; TOPOGRAPHY; EVOLUTION; VALLEYS; GRAVITY; BRINES; ORIGIN; WATER; MODEL; CO2 AB [1] The "White Mars'' hypothesis asserts that CO2 gas-driven debris flows were responsible for carving the outflow channels, the valley networks and the gullies on Mars rather than liquid water. This model further asserts that liquid water has been confined to the deep subsurface unable to find egress to erode the surface. We show that the subsurface of Mars, especially when major fluvial features formed, is unlikely to have been as cold as this model suggests and that liquid water would be present much closer to the surface than predicted by "White Mars''. The assumptions of the "White Mars'' hypothesis regarding globally-averaged crustal heat flow are below most estimates of the current thermal state of the Martian crust, and well below probable values 2 Gyr or more ago. Likewise, the assumed value of crustal thermal conductivity in "White Mars'' is inconsistent with the CO2 dominated cryosphere of the model. C1 Univ Texas, Richardson, TX 75083 USA. NASA, Ames Res Ctr, Ctr Mars Explorat, SETI Inst, Moffett Field, CA 94035 USA. RP Urquhart, ML (reprint author), Univ Texas, Richardson, TX 75083 USA. NR 29 TC 3 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 JUN 20 PY 2003 VL 30 IS 12 AR 1622 DI 10.1029/2002GL016158 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 693XG UT WOS:000183743200001 ER PT J AU Melbourne, TI Webb, FH AF Melbourne, TI Webb, FH TI Slow but not quite silent SO SCIENCE LA English DT Editorial Material ID SOUTHWEST JAPAN; SUBDUCTION; METAMORPHISM; EARTHQUAKES; TREMOR C1 Cent Washington Univ, Dept Geol Sci, Ellensburg, WA 98926 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Melbourne, TI (reprint author), Cent Washington Univ, Dept Geol Sci, Ellensburg, WA 98926 USA. NR 11 TC 23 Z9 24 U1 0 U2 2 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD JUN 20 PY 2003 VL 300 IS 5627 BP 1886 EP 1887 DI 10.1126/science.1086163 PG 2 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 691RN UT WOS:000183619400026 PM 12817131 ER PT J AU Chaban, GM Xantheas, SS Gerber, RB AF Chaban, GM Xantheas, SS Gerber, RB TI Anharmonic vibrational spectroscopy of the F(-)(H(2)O)(n) complexes, n=1, 2 SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID SELF-CONSISTENT-FIELD; AB-INITIO CALCULATIONS; WATER CLUSTERS; I CLUSTERS; MOLECULAR CALCULATIONS; ELECTRON CORRELATION; BINDING-ENERGY; WAVE-FUNCTIONS; BOND-ENERGY; BASIS SETS AB We report anharmonic vibrational spectra (fundamentals, first overtones) for the F(-)(H(2)O) and F(-)(H(2)O)(2) clusters computed at the MP2 and CCSD(T) levels of theory with basis sets of triple-zeta quality. Anharmonic corrections were estimated via the correlation-corrected vibrational self-consistent field (CC-VSCF) method. The CC-VSCF anharmonic spectra obtained on the potential energy surfaces evaluated at the CCSD(T) level of theory are the first ones reported at a correlated level beyond MP2. We have found that the average basis set effect (TZP vs aug-cc-pVTZ) is on the order of 30-40 cm(-1), whereas the effects of different levels of electron correlation [MP2 vs CCSD(T)] are smaller, 20-30 cm(-1). However, the basis set effect is much larger in the case of the H-bonded O-H stretch of the F(-)(H(2)O) cluster amounting to 100 cm(-1) for the fundamentals and 200 cm(-1) for the first overtones. Our calculations are in agreement with the limited available set of experimental data for the F(-)(H(2)O) and F(-)(H(2)O)(2) systems and provide additional information that can guide further experimental studies. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Pacific NW Natl Lab, Div Chem Sci, Richland, WA 99352 USA. Univ Calif Irvine, Dept Chem, Irvine, CA 92697 USA. Hebrew Univ Jerusalem, Dept Phys Chem, IL-91904 Jerusalem, Israel. Hebrew Univ Jerusalem, Fritz Haber Res Ctr, IL-91904 Jerusalem, Israel. RP Chaban, GM (reprint author), NASA, Ames Res Ctr, Mail Stop T257B-1, Moffett Field, CA 94035 USA. EM chaban@nas.nasa.gov; sotiris.xantheas@pnl.gov RI Xantheas, Sotiris/L-1239-2015 NR 39 TC 50 Z9 50 U1 0 U2 0 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 JUN 19 PY 2003 VL 107 IS 24 BP 4952 EP 4956 DI 10.1021/jp0343483 PG 5 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 691EP UT WOS:000183592100025 ER PT J AU Noor, AK Bechtel, SE Ghosh, S AF Noor, AK Bechtel, SE Ghosh, S TI Arthur W. Leissa 70th birthday issue - Preface SO JOURNAL OF SOUND AND VIBRATION LA English DT Editorial Material C1 Old Dominion Univ, NASA, Langley Res Ctr, Ctr Adv Engn Environm, Hampton, VA 23681 USA. Ohio State Univ, Dept Mech Engn, Columbus, OH 43210 USA. RP Noor, AK (reprint author), Old Dominion Univ, NASA, Langley Res Ctr, Ctr Adv Engn Environm, Mail Stop 201, Hampton, VA 23681 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU ACADEMIC PRESS LTD ELSEVIER SCIENCE LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 0022-460X J9 J SOUND VIB JI J. Sound Vibr. PD JUN 19 PY 2003 VL 263 IS 5 BP 961 EP 962 DI 10.1016/S0022-460X(03)00266-9 PG 2 WC Acoustics; Engineering, Mechanical; Mechanics SC Acoustics; Engineering; Mechanics GA 692FE UT WOS:000183649700001 ER PT J AU Noor, AK AF Noor, AK TI Arthur Leissa - a biographical sketch SO JOURNAL OF SOUND AND VIBRATION LA English DT Biographical-Item C1 Old Dominion Univ, NASA, Langley Res Ctr, Ctr Adv Eng Environm, Hampton, VA 23681 USA. RP Noor, AK (reprint author), Old Dominion Univ, NASA, Langley Res Ctr, Ctr Adv Eng Environm, Mail Stop 201, Hampton, VA 23681 USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU ACADEMIC PRESS LTD ELSEVIER SCIENCE LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 0022-460X J9 J SOUND VIB JI J. Sound Vibr. PD JUN 19 PY 2003 VL 263 IS 5 BP 963 EP 964 DI 10.1016/S0022-460X(03)00267-0 PG 2 WC Acoustics; Engineering, Mechanical; Mechanics SC Acoustics; Engineering; Mechanics GA 692FE UT WOS:000183649700002 ER PT J AU Walch, SP AF Walch, SP TI Model calculations of the electron affinities and ionization potentials of DNA SO CHEMICAL PHYSICS LETTERS LA English DT Article ID THYMINE; BASES AB We have studied the electron affinities and ionization potentials for models of DNA. We conclude that removing an electron is most favorable on the PO(4)(-) groups; whereas, addition of an electron is most favorable on a nucleic acid. The computed electron affinities are 1.9, 4.8, 5.7, and 7.9 kcal/mol for adenine, cytosine, guanine, and thymine, respectively. Our best estimate of the IP for hydrated DNA is 4.5 eV and for hydrated DNA plus Na(+) counter ions is 5.6 eV. (C) 2003 Elsevier Science B.V. All rights reserved. C1 NASA, Ames Res Ctr, ELORET, Moffett Field, CA 94035 USA. RP Walch, SP (reprint author), NASA, Ames Res Ctr, ELORET, Mail Stop 230-3, Moffett Field, CA 94035 USA. EM swalch@mail.arc.nasa.gov NR 14 TC 23 Z9 23 U1 0 U2 4 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 JUN 18 PY 2003 VL 374 IS 5-6 BP 496 EP 500 DI 10.1016/S0009-2614(03)00735-8 PG 5 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 697MA UT WOS:000183945900013 ER PT J AU Walch, SP AF Walch, SP TI On the reaction of N and O atoms with carbon nanotubes SO CHEMICAL PHYSICS LETTERS LA English DT Article ID SIMULATIONS; DYNAMICS; HYDROGEN AB We have studied the reaction of N and 0 atoms with a (9,0) carbon nanotube using clusters and the ONIOM method with the B3LYP/6-31G* level of theory. For both N and 0 atoms in their ground state, addition to the CNT requires a surface crossing and presumably involves a barrier, while we show that addition of the excited state of N(D-2) has no barrier, and we believe this also to be true for O(D-1). Both N and 0 atoms bond in a bridged structure and have bond strengths of 25.0 and 67.9 kcal/mol (estimated), respectively, with respect to CNT plus the ground state of the N or 0 atom. (C) 2003 Elsevier Science B.V. All rights reserved. C1 NASA, Ames Res Ctr, ELORET, Moffett Field, CA 94035 USA. RP Walch, SP (reprint author), NASA, Ames Res Ctr, ELORET, Mail Stop 230-3, Moffett Field, CA 94035 USA. NR 13 TC 26 Z9 26 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 JUN 18 PY 2003 VL 374 IS 5-6 BP 501 EP 505 DI 10.1016/S0009-2614(03)00736-X PG 5 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 697MA UT WOS:000183945900014 ER PT J AU Erickson, DJ Hernandez, JL Ginoux, P Gregg, WW McClain, C Christian, J AF Erickson, DJ Hernandez, JL Ginoux, P Gregg, WW McClain, C Christian, J TI Atmospheric iron delivery and surface ocean biological activity in the Southern Ocean and Patagonian region SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID EQUATORIAL PACIFIC-OCEAN; LAST GLACIAL MAXIMUM; MODEL; PRODUCTIVITY; AEROSOLS; CLIMATE AB [1] Iron is a limiting nutrient for biologic activity in much of the world ocean. We present a method to quantitatively address the response of surface ocean biology to inputs of atmospheric Fe associated with atmospheric dust. We merge two enabling technologies, global models of Earth system processes and satellite derived chlorophyll concentrations to assess the importance of Fe in oceanic biogeochemistry. We present an objective correlation analysis to elucidate the spatial response of chlorophyll to iron flux considering the ocean surface meridional center of mass in areas with high correlation. Several regions between 40 degreesS and 60 degreesS show correlations from 0.6 to 0.95, significant at the 0.05 level, particularly the Patagonian region. Surface chlorophyll and iron flux follow similar patterns, however chlorophyll may be displaced to different latitudes than where Fe input occurs due to meridional ocean transport. C1 Oak Ridge Natl Lab, Div Math & Comp Sci, Oak Ridge, TN 37831 USA. Univ Maryland Baltimore Cty, GEST, Baltimore, MD 21228 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Erickson, DJ (reprint author), Oak Ridge Natl Lab, Div Math & Comp Sci, Oak Ridge, TN 37831 USA. RI Ginoux, Paul/C-2326-2008 OI Ginoux, Paul/0000-0003-3642-2988 NR 20 TC 50 Z9 50 U1 0 U2 11 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 JUN 18 PY 2003 VL 30 IS 12 AR 1609 DI 10.1029/2003GL017241 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 693XC UT WOS:000183742800006 ER PT J AU Mann, ME Schmidt, GA AF Mann, ME Schmidt, GA TI Ground vs. surface air temperature trends: Implications for borehole surface temperature reconstructions SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID NORTH-AMERICA; GISS GCM; MODEL AB [1] We have analyzed the relationship between surface air temperature ( SAT), ground surface temperature (GST), and snow cover (SNC) over the terrestrial Northern Hemisphere based on general circulation model (GCM) simulations using GISS modelE forced with the observed SST and radiative forcing changes from 1951 - 1998. While SAT is the dominant influence on GST during the warm-season, it explains only half of the variance in GST during the cold-season, with SNC and pre-conditioning by prior warm-season SAT also exhibiting a sizeable and, in places, dominant influence. During a period of coincident surface warming and cold-season snowcover decrease in the model ( 1971 - 1998), mean GST increases are 0.2 degreesC less than those in SAT, a consequence of greater exposure of the ground surface to winter cold air outbreaks. Interpretations of past SAT trends from borehole-based GST reconstructions may therefore be substantially biased by seasonal influences and snow cover changes. C1 Univ Virginia, Dept Environm Sci, Charlottesville, VA 22902 USA. NASA, Goddard Inst Space Studies, New York, NY 10025 USA. NASA, Ctr Climate Syst Res, New York, NY 10025 USA. RP Mann, ME (reprint author), Univ Virginia, Dept Environm Sci, Charlottesville, VA 22902 USA. RI Schmidt, Gavin/D-4427-2012; Mann, Michael/B-8472-2017 OI Schmidt, Gavin/0000-0002-2258-0486; Mann, Michael/0000-0003-3067-296X NR 18 TC 57 Z9 59 U1 0 U2 10 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 JUN 18 PY 2003 VL 30 IS 12 AR 1607 DI 10.1029/2003GL017170 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 693XC UT WOS:000183742800003 ER EF