FN Thomson Reuters Web of Science™ VR 1.0 PT J AU Kuhn, DR AF Kuhn, DR TI Fault classes and error detection capability of specification-based testing SO ACM TRANSACTIONS ON SOFTWARE ENGINEERING AND METHODOLOGY LA English DT Article DE theory; verification; testing AB Some varieties of specification-based testing rely upon methods for generating test cases from predicates in a software specification. These methods derive various test conditions from logic expressions, with the aim of detecting different types of faults. Some authors have presented empirical results on the ability of specification-based test generation methods to detect failures. This article describes a method for computing the conditions that must be covered by a test set for the test set to guarantee detection of the particular fault class. It is shown that there is a coverage hierarchy to fault classes that is consistent with, and may therefore explain, experimental results on fault-based testing. The method is also shown to be effective for computing MCDC-adequate tests. C1 NIST, Software Qual Grp, Gaithersburg, MD 20899 USA. RP Kuhn, DR (reprint author), NIST, Software Qual Grp, Bldg 820,Room 562, Gaithersburg, MD 20899 USA. NR 21 TC 69 Z9 73 U1 0 U2 0 PU ASSOC COMPUTING MACHINERY PI NEW YORK PA 1515 BROADWAY, NEW YORK, NY 10036 USA SN 1049-331X J9 ACM T SOFTW ENG METH JI ACM Trans. Softw. Eng. Methodol. PD OCT PY 1999 VL 8 IS 4 BP 411 EP 424 DI 10.1145/322993.322996 PG 14 WC Computer Science, Software Engineering SC Computer Science GA 268VZ UT WOS:000084439300003 ER PT J AU Marino, M Devaney, J Levin, B Tully, L AF Marino, M Devaney, J Levin, B Tully, L TI Mitochondrial DNA polymorphism detection and heteroplasmy quantitation using high performance liquid chromatography. SO AMERICAN JOURNAL OF HUMAN GENETICS LA English DT Meeting Abstract C1 Transgenom Inc, Gaithersburg, MD USA. Natl Inst Stand & Technol, Div Biotechnol, Gaithersburg, MD 20899 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0002-9297 J9 AM J HUM GENET JI Am. J. Hum. Genet. PD OCT PY 1999 VL 65 IS 4 SU S MA 525 BP A100 EP A100 PG 1 WC Genetics & Heredity SC Genetics & Heredity GA 241JQ UT WOS:000082879800527 ER PT J AU Graczyk, TK Thompson, RCA Fayer, R Adams, P Morgan, UM Lewis, EJ AF Graczyk, TK Thompson, RCA Fayer, R Adams, P Morgan, UM Lewis, EJ TI Giardia duodenalis cysts of Genotype A recovered from clams in the Chesapeake Bay subestuary, Rhode River SO AMERICAN JOURNAL OF TROPICAL MEDICINE AND HYGIENE LA English DT Article ID HERON ARDEA-HERODIAS; CRYPTOSPORIDIUM-PARVUM; CRASSOSTREA-VIRGINICA; WATER; OOCYSTS; SAMPLES AB Filter-feeding molluscan shellfish can concentrate zoonotic and anthroponotic waterborne pathogens. Cysts of Giardia sp. were detected by immunofluorescent antibodies in tissues of the clams Macoma balthica and M. mitchelli from Rhode River, a Chesapeake Bay (Maryland) subestuary. Molecular tests identified the cysts as Giardia duodenalis Genotype A, the most common genotype recovered from humans. Macoma clams are burrowers in mud or sandy-mud substrata and preferentially feed on the surface sediment layer. Waterborne Giardia cysts settle rapidly to the bottom in slow-moving waters and contaminate the sediment. Macoma clams do not have economic value, but can serve as biologic indicators of sediment contamination with Giardia sp. cysts of public health importance. These clams can be used for sanitary assessment of water quality. C1 Johns Hopkins Univ, Sch Hyg & Publ Hlth, Dept Mol Microbiol & Immunol, Baltimore, MD 21205 USA. Murdoch Univ, Sch Vet Studies, World Hlth Org, Collaborating Ctr Mol Epidemiol Parasit Infect, Murdoch, WA 6150, Australia. Murdoch Univ, Sch Vet Studies, State Agr Biotechnol Ctr, Murdoch, WA 6150, Australia. USDA ARS, Immun & Dis Resistance Lab, Livestock & Poultry Sci Inst, Beltsville, MD 20705 USA. US Dept Commerce, Cooperative Oxford Lab, Ctr Coastal Environm Hlth & Biomol Res, Natl Ocean Serv, Oxford, MD 21654 USA. Johns Hopkins Univ, Sch Hyg & Publ Hlth, Dept Environm Hlth Sci, Baltimore, MD 21205 USA. RP Graczyk, TK (reprint author), Johns Hopkins Univ, Sch Hyg & Publ Hlth, Dept Mol Microbiol & Immunol, Baltimore, MD 21205 USA. NR 38 TC 39 Z9 42 U1 0 U2 2 PU AMER SOC TROP MED & HYGIENE PI MCLEAN PA 8000 WESTPARK DRIVE SUITE 130, MCLEAN, VA 22101 USA SN 0002-9637 J9 AM J TROP MED HYG JI Am. J. Trop. Med. Hyg. PD OCT PY 1999 VL 61 IS 4 BP 526 EP 529 PG 4 WC Public, Environmental & Occupational Health; Tropical Medicine SC Public, Environmental & Occupational Health; Tropical Medicine GA 250FA UT WOS:000083377300003 PM 10548284 ER PT J AU Smeller, JM AF Smeller, JM TI Automatic titration of cerium SO AMERICAN LABORATORY LA English DT Article C1 NIST, Gaithersburg, MD 20899 USA. RP Smeller, JM (reprint author), NIST, 100 Bur Dr, Gaithersburg, MD 20899 USA. NR 6 TC 0 Z9 0 U1 0 U2 1 PU INT SCIENTIFIC COMMUN INC PI SHELTON PA PO BOX 870, 30 CONTROLS DRIVE, SHELTON, CT 06484-0870 USA SN 0044-7749 J9 AM LAB JI Am. Lab. PD OCT PY 1999 VL 31 IS 21 BP 6 EP + PG 0 WC Chemistry, Analytical; Instruments & Instrumentation SC Chemistry; Instruments & Instrumentation GA 248YR UT WOS:000083304800001 ER PT J AU Cole, KD Tellez, CM Nguyen, RB AF Cole, KD Tellez, CM Nguyen, RB TI Modification of the electrokinetic properties of reversible electrophoresis gels for the separation and preparation of DNA - Addition of linear polymers SO APPLIED BIOCHEMISTRY AND BIOTECHNOLOGY LA English DT Article DE electrophoresis gel; DNA; electroosmosis; separation; reversible; preparative; gellan gum ID CAPILLARY ELECTROPHORESIS; GELLAN; MECHANISM; FRAGMENTS; BUFFER AB The effect of adding linear polymers to a novel reversible electrophoretic media was measured. Reversible gels are formed using the polyanionic carbohydrate polymer, gellan gum. Gellan gum forms strong stable gels in the presence of divalent cations or diamines. The gels are reversible (return to solution) by changing the ionic environment or pH. Gellan gum is an anionic polymer, and the electrophoresis gels have considerable electroosmotic flow (EOF) toward the negative electrode. We measured the EOF in gellan gum electrophoresis gels as a function of gel concentration, buffer composition, and linear polymer additive. The linear polymers used in this study were polyethylene oxide and hydroxyethyl cellulose. Both polymers reduced EOF in the gels, in a manner dependent on molecular weight. Polymers with a high molecular weight were more effective at reducing EOF. The addition of polymers increased the resolution of low molecular weight DNA. Native gellan gum resolved DNA from approx 50,000 to 1000 bp. Addition of the polymers resolved DNA down to approx 50 bp, in some instances. The influence of the polymers on circular plasmid DNA was also investigated. Addition of high molecular weight polyethylene oxide reduced the electrophoretic mobility of the nicked circular form compared to the supercoiled form. C1 Natl Inst Stand & Technol, Bioproc Engn Grp, Div Biotechnol, Gaithersburg, MD 20899 USA. Univ Illinois, Dept Mech & Ind Engn, Urbana, IL 61801 USA. RP Cole, KD (reprint author), Natl Inst Stand & Technol, Bioproc Engn Grp, Div Biotechnol, Gaithersburg, MD 20899 USA. NR 29 TC 4 Z9 4 U1 0 U2 2 PU HUMANA PRESS INC PI TOTOWA PA 999 RIVERVIEW DRIVE SUITE 208, TOTOWA, NJ 07512 USA SN 0273-2289 J9 APPL BIOCHEM BIOTECH JI Appl. Biochem. Biotechnol. PD OCT PY 1999 VL 82 IS 1 BP 57 EP 76 DI 10.1385/ABAB:82:1:57 PG 20 WC Biochemistry & Molecular Biology; Biotechnology & Applied Microbiology SC Biochemistry & Molecular Biology; Biotechnology & Applied Microbiology GA 284YM UT WOS:000085360500005 PM 10707807 ER PT J AU Stone, JA Stejskal, A Howard, L AF Stone, JA Stejskal, A Howard, L TI Absolute interferometry with a 670-nm external cavity diode laser SO APPLIED OPTICS LA English DT Article ID WAVELENGTH; METROLOGY AB In the past few years there has been much interest in use of tunable diode lasers for absolute interferometry. Here we report on use of an external cavity diode laser operating in the visible (lambda - 670 nm) for absolute distance measurements. Under laboratory conditions we achieve better than 1-mu m standard uncertainty in distance measurements over a range of 5 m, but significantly larger uncertainties will probably be more typical of shop-floor measurements where conditions are far from ideal. We analyze the primary sources of uncertainty limiting the performance of wavelength-sweeping methods for absolute interferometry, and we discuss how errors can be minimized. Many errors are greatly magnified when the wavelength sweeping technique is used; sources of error that are normally relevant only at the nanometer level when standard interferometric techniques are used may be significant here for measurements at the micrometer level. C1 Natl Inst Stand & Technol, Div Precis Engn, Engn Metrol Grp, Gaithersburg, MD 20899 USA. RP Stone, JA (reprint author), Natl Inst Stand & Technol, Div Precis Engn, Engn Metrol Grp, Stop 8211,100 Bur Dr, Gaithersburg, MD 20899 USA. EM jack.stone@nist.gov NR 21 TC 57 Z9 58 U1 1 U2 4 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1559-128X EI 2155-3165 J9 APPL OPTICS JI Appl. Optics PD OCT 1 PY 1999 VL 38 IS 28 BP 5981 EP 5994 DI 10.1364/AO.38.005981 PG 14 WC Optics SC Optics GA 244YV UT WOS:000083079100011 PM 18324118 ER PT J AU Asmail, CC Parr, AC Hsia, JJ AF Asmail, CC Parr, AC Hsia, JJ TI Rayleigh scattering limits for low-level bidirectional reflectance distribution function measurements (vol 33, pg 6084, 1994) SO APPLIED OPTICS LA English DT Correction AB In previous research [C. C. Asmail et al. Appl. Opt. 33, 6084-6091 (1994)] an estimate was given of the low-level bidirectional reflectance distribution function (BRDF) limit due to Rayleigh scattering from the air molecules within the detector field of view. Although the underlying model was correct, a fault in the derivation led to a conclusion that contains an erroneous angular factor. A cosine factor in the equivalent BRDF derived by Asmail ef al. [Appl. Opt. 33, 6084-6091 (1994)], which was considered unphysical in that treatment, is incorrect and can obscure the correction in certain circumstances. The treatment below calculates the scattered flux from the gas molecules in the field of view and compares it with the flux scattered from a sample in the same incident beam. C1 Natl Inst Stand & Technol, Opt Technol Div, Gaithersburg, MD 20899 USA. RP Asmail, CC (reprint author), Natl Inst Stand & Technol, Opt Technol Div, MS 8440,100 Bur Dr, Gaithersburg, MD 20899 USA. EM albert.parr@nist.gov NR 4 TC 2 Z9 2 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 OCT 1 PY 1999 VL 38 IS 28 BP 6027 EP 6028 DI 10.1364/AO.38.006027 PG 2 WC Optics SC Optics GA 244YV UT WOS:000083079100016 ER PT J AU Oueini, SS Nayfeh, AH Pratt, JR AF Oueini, SS Nayfeh, AH Pratt, JR TI A review of development and implementation of an active nonlinear vibration absorber SO ARCHIVE OF APPLIED MECHANICS LA English DT Article DE active feedback control; nonlinear absorber; smart structures; PZT; Terfenol-D ID FLEXIBLE-STRUCTURES AB We present an account of an implementation of an active nonlinear vibration absorber that we have developed. The control technique exploits the saturation phenomenon that is known to occur in quadratically-coupled multi-degree-of-freedom systems subjected to primary excitation and possessing a two-to-one internal resonance. The technique is based on introducing an absorber and coupling it with the structure through a sensor and an actuator, where the feedback and control signals are quadratic. First, we consider the case of controlling the vibrations of a single-degree-of-freedom system. We develop the equations governing the response of the closed-loop system and use the method of multiple scales to obtain an approximate solution. We investigate the performance of the control strategy by studying its steady-state and transient characteristics. Additionally, we compare the performance of the quadratic absorber with that of a linear absorber. Then, we present theoretical and experimental results that demonstrate the versatility of the technique. We design an electronic circuit to emulate the absorber and use a variety of sensors and actuators to implement the active control strategy. First, we use a motor and a potentiometer to control the vibration of a rigid beam. We develop a plant model that includes Coulomb friction and demonstrate that the closed-loop system exhibits the saturation phenomenon. Second, we extend the strategy to multi-degree-of-freedom systems. We use PZT ceramics and strain gages to suppress vibrations of flexible steel beams when subjected to single- and simultaneous two-mode excitations. Third, we employ Terfenol-D, a nonlinear actuator, and accelerometers to control the vibrations of flexible beams. In all instances, the technique is successful in reducing the response amplitude of the structures. C1 Virginia Polytech Inst & State Univ, Dept Engn Sci & Mech, Blacksburg, VA 24061 USA. Natl Inst Stand & Technol, Mfg Engn Lab, Gaithersburg, MD 20899 USA. RP Oueini, SS (reprint author), Virginia Polytech Inst & State Univ, Dept Engn Sci & Mech, MC 0219, Blacksburg, VA 24061 USA. NR 25 TC 22 Z9 23 U1 1 U2 11 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0939-1533 J9 ARCH APPL MECH JI Arch. Appl. Mech. PD OCT PY 1999 VL 69 IS 8 BP 585 EP 620 DI 10.1007/s004190050245 PG 36 WC Mechanics SC Mechanics GA 257PB UT WOS:000083789600007 ER PT J AU Bargar, TA Sills-McMurry, C Dickerson, RL Rhodes, WE Cobb, GP AF Bargar, TA Sills-McMurry, C Dickerson, RL Rhodes, WE Cobb, GP TI Relative distribution of polychlorinated biphenyls among tissues of neonatal American alligators (Alligator mississippiensis) SO ARCHIVES OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY LA English DT Article ID CHORIOALLANTOIC MEMBRANES; EGGS AB Recent papers have investigated the utility of chemical analysis of the chorioallantoic membrane (CAM) as a nonlethal indicator of avian and reptilian exposure to persistent environmental contaminants. This study was undertaken to evaluate the chemical distribution among fat, CAM, and residual yolk tissues of live neonatal American alligators (Alligator mississippiensis) to investigate the potential utility of CAM use as a nonlethal indicator of exposure to polychlorinated biphenyls (PCBs). CAMs were collected from neonatal alligators at hatch, whereas yolk sacs and fat tissues were taken from each animal at euthanization (3 weeks posthatch). All collected tissue samples were separately Soxhlet extracted and analyzed by GC/ECD for PCBs. Log normalized, individual PCB congener concentrations in CAMs were significantly correlated with concentrations in fat (r(2) = 0.62) and yell; (r(2) = 0.56) tissues. Coefficients of determination from comparisons of homologue group concentrations varied from 0.13 to 0.90. Residue levels in neonatal oviparous organism tissues may be qualitatively assessed through chemical analyses of CAM tissues removed from discarded eggshells. C1 Texas Tech Univ, Dept Biol Sci, Inst Environm & Human Hlth, Lubbock, TX 79409 USA. S Carolina Dept Nat Resources, Dennis Wildlife Res Ctr, Bonneau, SC 29413 USA. RP Bargar, TA (reprint author), NOS, CCEHBR, 219 Ft Johnson Rd, Charleston, SC 29412 USA. FU NIEHS NIH HHS [ES-0472] NR 13 TC 13 Z9 13 U1 0 U2 1 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0090-4341 J9 ARCH ENVIRON CON TOX JI Arch. Environ. Contam. Toxicol. PD OCT PY 1999 VL 37 IS 3 BP 364 EP 368 PG 5 WC Environmental Sciences; Toxicology SC Environmental Sciences & Ecology; Toxicology GA 235RC UT WOS:000082555500011 PM 10473793 ER PT J AU Shull, JM Roberts, D Giroux, ML Penton, SV Fardal, MA AF Shull, JM Roberts, D Giroux, ML Penton, SV Fardal, MA TI The metagalactic ionizing radiation field at low redshift SO ASTRONOMICAL JOURNAL LA English DT Article DE diffuse radiation; intergalactic medium; galaxies : Seyfert; galaxies : starburst ID OPTICAL LUMINOSITY FUNCTION; HUBBLE-SPACE-TELESCOPE; H-ALPHA EMISSION; STAR-FORMATION; ABSORPTION SYSTEMS; SEYFERT-1 NUCLEI; LYMAN CONTINUUM; DEEP FIELD; EVOLUTION; GALAXIES AB We compute the ionizing radiation held at low redshift, arising from Seyferts, QSOs, and starburst galaxies. This calculation combines recent Seyfert luminosity functions, extrapolated ultraviolet fluxes from our IUE-AGN database, and a new intergalactic opacity model based on Hubble Space Telescope and Keck Lye: absorber surveys. At z = 0 for AGNs only, our best estimate for the specific intensity at 1 ryd is I(0) = 1.3(-0.5)(+0.8) x 10(-23) ergs cm(-2) s(-1) Hz(-1) sr(-1), independent of H(0), Omega(0), and Lambda. The one-sided ionizing photon flux is Phi(ion) approximate to 3400(-1300)(+2100) photons cm(-2) s(-1), and the H I photoionization rate is Gamma(H I) = 3.2(-1.2)(+2.0) x 10(-14) s(-1), for alpha(s) = 1.8. We also derive Gamma(H I) for z = 0-4. These error ranges reflect uncertainties in the spectral indexes for the ionizing EUV (alpha(s) = 1.8 +/- 0.3) and the optical/UV (alpha(UV) = 0.86 +/- 0.05), the IGM opacity model, the range of Seyfert luminosities (0.001L(*)-100L(*)), and the completeness of the luminosity functions. Our estimate is a factor of 3 lower than the most stringent upper limits on the ionizing background (Phi(ion) < 10(4) photons cm(-2) s(-1)) obtained from H alpha observations in external clouds, and it lies within the range implied by other indirect measures. Starburst galaxies with a sufficiently large Lyman continuum escape fraction, [f(esc)] greater than or equal to 0.05, may provide a comparable background to AGNs, I(0)(z = 0) = 1.1(-0.7)(+1.5) x 10(-23) ergs cm(-2) s(-1) Hz(-1) sr(-1). An additional component of the ionizing background of this magnitude would violate neither upper limits from Ha observations nor the acceptable range from other measurements. C1 Univ Colorado, Dept Astrophys & Planetary Sci, Ctr Astrophys & Space Astron, Boulder, CO 80309 USA. Univ Colorado, JILA, Boulder, CO 80309 USA. Natl Inst Stand & Technol, Boulder, CO USA. RP Shull, JM (reprint author), Univ Colorado, Dept Astrophys & Planetary Sci, Ctr Astrophys & Space Astron, Campus Box 389, Boulder, CO 80309 USA. EM mshull@casa.colorado.edu; dcr12@cornell.edu; giroux@casa.colorado.edu; spenton@casa.colorado.edu; fardal@weka.phast.umass.edu NR 74 TC 112 Z9 112 U1 0 U2 0 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 OCT PY 1999 VL 118 IS 4 BP 1450 EP 1460 DI 10.1086/301053 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 251CR UT WOS:000083427500003 ER PT J AU Terndrup, DM Krishnamurthi, A Pinsonneault, MH Stauffer, JR AF Terndrup, DM Krishnamurthi, A Pinsonneault, MH Stauffer, JR TI A search for photometric rotation periods in low-mass stars and brown dwarfs in the Pleiades SO ASTRONOMICAL JOURNAL LA English DT Article DE open clusters and associations : individual (Pleiades); stars : activity; stars : low-mass, brown dwarfs; stars : rotation ID SOLAR-TYPE STARS; TIME-SERIES ANALYSIS; ALPHA-PERSEI; CHROMOSPHERIC ACTIVITY; LITHIUM DEPLETION; MAIN-SEQUENCE; EVOLUTION; CLUSTER; VELOCITIES; FIELD AB We have photometrically monitored (Cousins I-c) eight low-mass stars and brown dwarfs that are probable members of the Pleiades. We derived rotation periods for two of the stars-HHJ 409 and CFHT-PL 8-to be 0.258 and 0.401 days, respectively. The masses of these stars ate near 0.4 and 0.08 M-., respectively; the latter is the second such object near the hydrogen-burning boundary for which a rotation period has been measured. We also observed HHJ 409 in V. The relative amplitude in the two bands shows that the spots in that star are about 200 K cooler than the stellar effective temperature of 3560 K and have a filling factor on the order of 13%. With one possible exception, the remaining stars in the sample do not show photometric variations larger than the mean error of measurement. We also examined the M9.5 V disk star 2MASS J0149090 + 295613, which had previously exhibited a strong flare event, but we did not detect any photometric variation. C1 Ohio State Univ, Dept Astron, Columbus, OH 43210 USA. Natl Inst Stand & Technol, Boulder, CO 80309 USA. Univ Colorado, JILA, Boulder, CO 80309 USA. Smithsonian Astrophys Observ, Cambridge, MA 02138 USA. RP Terndrup, DM (reprint author), Ohio State Univ, Dept Astron, 174 W 18Th Ave, Columbus, OH 43210 USA. NR 41 TC 45 Z9 45 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-6256 J9 ASTRON J JI Astron. J. PD OCT PY 1999 VL 118 IS 4 BP 1814 EP 1818 DI 10.1086/301061 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 251CR UT WOS:000083427500031 ER PT J AU Romanov, P AF Romanov, P TI Urban influence on cloud cover estimated from satellite data SO ATMOSPHERIC ENVIRONMENT LA English DT Article; Proceedings Paper CT International Conference on Urban Climatology (ICUC 96) CY JUN 10-14, 1996-1997 CL ESSEN, GERMANY DE cloud amount; satellite remote sensing; urban effects ID HEAT; CLIMATOLOGY AB Quantitative assessment of the influence of a big city on the cloud cover was made using time series of satellite measurements. Data from the advanced very high resolution radiometer (AVHRR) on board NOAA satellites received during 1993-1996 over the Central European part of Russia have been processed to derive statistics on spatial distribution of cloudiness for a territory of approximately 7000 km(2) covering Moscow (55.7 N, 37.6 E) and adjacent areas. Two basic cloud cover characteristics were studied: the total fractional cloud cover and the frequency of occurrence of cloudless scenes (or the clear-sky frequency). Results of the study show that the urban effect is most pronounced during spring and summer periods when a considerable increase in the cloud amount over most of the built-up city area is observed. The winter period presents only a slight evidence of the urban-induced modification of the cloud amount spatial distribution pattern. The average clear-sky frequency in the centre of the city was found to be 5.4% lower than in the nearest suburbs. No well-defined seasonal variations of the urban-rural difference in the clear-sky frequency were detected. (C) 1999 Published by Elsevier Science Ltd. All rights reserved. C1 Res Ctr Planeta RPA, Moscow 123242, Russia. RP NOAA, NESDIS, ORA, WWB 712,5200 Auth Rd, Camp Springs, MD 20746 USA. EM promanov@nesdis.noaa.gov RI Romanov, Peter/F-5622-2010 OI Romanov, Peter/0000-0002-2153-8307 NR 20 TC 11 Z9 11 U1 0 U2 5 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1352-2310 EI 1873-2844 J9 ATMOS ENVIRON JI Atmos. Environ. PD OCT PY 1999 VL 33 IS 24-25 BP 4163 EP 4172 DI 10.1016/S1352-2310(99)00159-4 PG 10 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA 230NN UT WOS:000082257400032 ER PT J AU Martien, KK Taylor, BL Slooten, E Dawson, S AF Martien, KK Taylor, BL Slooten, E Dawson, S TI A sensitivity analysis to guide research and management for Hector's dolphin SO BIOLOGICAL CONSERVATION LA English DT Article DE Hector's dolphin; sensitivity analysis; gillnet mortality; management objectives ID CONSERVATION AB Hector's dolphin (Cephalorhynchus hectori) is an uncommon endemic of New Zealand which is suspected to be in decline due to entanglement mortality. However, uncertainty in available data has led to a dispute between the New Zealand Ministry of Fisheries and the New Zealand Department of Conservation over the status of this species. We use a density-dependent deterministic model to predict the future abundance and geographic distribution of Hector's dolphin under different scenarios of fisheries management. We then examine the sensitivity of this model to a number of parameters for which few or no data are available. We find that two populations of Hector's dolphins are predicted to decline in the future even when the most optimistic parameter estimates are used. The status of the third population is dependent upon the estimate of maximum annual population growth rate. Because of the dependence of final abundance estimates on the estimates of entanglement mortality rates and maximum population growth rate, research efforts should be concentrated on estimating these parameters. (C) 1999 Published by Elsevier Science Ltd. All rights reserved. C1 Univ Calif San Diego, Dept Biol 0116, La Jolla, CA 92093 USA. SW Fisheries Sci Ctr, La Jolla, CA 92038 USA. Univ Otago, Dept Marine Sci, Dunedin, New Zealand. RP Martien, KK (reprint author), Univ Calif San Diego, Dept Biol 0116, La Jolla, CA 92093 USA. RI Slooten, Elisabeth/E-7425-2014; OI Slooten, Elisabeth/0000-0001-5384-511X; Dawson, Stephen/0000-0003-3182-0186 NR 16 TC 25 Z9 31 U1 3 U2 16 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0006-3207 J9 BIOL CONSERV JI Biol. Conserv. PD OCT PY 1999 VL 90 IS 3 BP 183 EP 191 DI 10.1016/S0006-3207(99)00020-8 PG 9 WC Biodiversity Conservation; Ecology; Environmental Sciences SC Biodiversity & Conservation; Environmental Sciences & Ecology GA 209UD UT WOS:000081066500004 ER PT J AU Kahl, JDW Zaitseva, NA Khattatov, V Schnell, RC Bacon, DM Bacon, J Radionov, V Serreze, MC AF Kahl, JDW Zaitseva, NA Khattatov, V Schnell, RC Bacon, DM Bacon, J Radionov, V Serreze, MC TI Radiosonde observations from the former Soviet "North Pole" series of drifting ice stations, 1954-90 SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article AB An historical archive of over 25 000 radiosonde observations from the former Soviet "North Pole" series of drifting ice stations has been compiled and made available to interested researchers. This archive is the only long-term set of meteorological sounding data over the Arctic Ocean. The digital archive is a result of the multiyear, collaborative efforts of a group of United States and Russian scientists and keypunch operators working under the auspices of Working Group VIII, an area of study within the United States-Russian Federation Agreement for Protection of the Environment and Natural Resources. The archive contains soundings from 21 drifting stations over the period 1954-90 and is being distributed by the National Snow and Ice Data Center in Boulder, Colorado. C1 Univ Wisconsin, Dept Math Sci, Atmospher Sci Grp, Milwaukee, WI 53201 USA. Russian Fed Serv Hydrometeorol & Environm Monitor, Cent Aerol Observ, Moscow, Russia. NOAA, CMDL, Mauna Loa Observ, Hilo, HI USA. Arctic & Antarctic Res Inst, St Petersburg 199226, Russia. Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. RP Kahl, JDW (reprint author), Univ Wisconsin, Dept Math Sci, Atmospher Sci Grp, Milwaukee, WI 53201 USA. NR 0 TC 11 Z9 11 U1 0 U2 2 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 OCT PY 1999 VL 80 IS 10 BP 2019 EP 2026 DI 10.1175/1520-0477(1999)080<2019:ROFTFS>2.0.CO;2 PG 8 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 239UJ UT WOS:000082787800002 ER PT J AU Pielke, RA Landsea, CN AF Pielke, RA Landsea, CN TI La Nina, El Nino, and Atlantic hurricane damages in the United States SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article ID TROPICAL CYCLONE ACTIVITY; SEA-SURFACE TEMPERATURE; PACIFIC; CLIMATOLOGY; FREQUENCY; ENSO AB Hurricanes result in considerable damage in the United States. Previous work has shown that Atlantic hurricane landfalls in the United States have a strong relationship with the El Nino-Southern Oscillation phenomena. This paper compares the historical record of La Nina and El Nino events defined by eastern Pacific sea surface temperature with a dataset of hurricane losses normalized to 1997 values. A significant relationship is found between the ENSO cycle and U.S. hurricane losses, with La Nina years exhibiting much more damage. Used appropriately, this relationship is of potential value to decision makers who are able to manage risk based on probabilistic information. C1 Natl Ctr Atmospher Res, Environm & Societal Impacts Grp, Boulder, CO 80307 USA. NOAA, Atlantic Oceanog & Meteorol Lab, Hurricane Res Div, Miami, FL 33149 USA. RP Pielke, RA (reprint author), Natl Ctr Atmospher Res, Environm & Societal Impacts Grp, POB 3000, Boulder, CO 80307 USA. NR 30 TC 134 Z9 136 U1 5 U2 23 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 OCT PY 1999 VL 80 IS 10 BP 2027 EP 2033 DI 10.1175/1520-0477(1999)080<2027:LNAENO>2.0.CO;2 PG 7 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 239UJ UT WOS:000082787800003 ER PT J AU Holle, RL Lopez, RE Zimmermann, C AF Holle, RL Lopez, RE Zimmermann, C TI Updated recommendations for lightning safety - 1998 SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article ID INJURIES; POLICY C1 NOAA, Natl Severe Storms Lab, Norman, OK 73069 USA. Global Atmospher Inc, Tucson, AZ USA. RP Holle, RL (reprint author), NOAA, Natl Severe Storms Lab, 1313 Halley Circle, Norman, OK 73069 USA. NR 21 TC 22 Z9 22 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 OCT PY 1999 VL 80 IS 10 BP 2035 EP 2041 DI 10.1175/1520-0477(1999)080<2035:URFLS>2.0.CO;2 PG 7 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 239UJ UT WOS:000082787800004 ER PT J AU Tsuboi, S Whitmore, PM Sokolowski, TJ AF Tsuboi, S Whitmore, PM Sokolowski, TJ TI Application of M-wp to deep and teleseismic earthquakes SO BULLETIN OF THE SEISMOLOGICAL SOCIETY OF AMERICA LA English DT Article AB The broadband moment magnitude M-wp (Tsuboi, et al., 1995) allows for the effective determination of earthquake magnitude by using broadband P waveforms. It was developed to determine moment magnitude of shallow earthquakes around the Japanese Islands for early tsunami warnings, Tsuboi ed al. (1995) demonstrated that M-wp shows good agreement with the M-w from Harvard centroid moment tensor (CMT) solutions. In the present study, we show that M-wp is also applicable to deep earthquakes and earthquakes recorded at teleseismic distances. The M-wp proves to be useful for quick, accurate size estimates of earthquakes recorded at both regional and teleseismic distances occurring at any depth. C1 Natl Def Acad, Dept Geosci, Yokosuka, Kanagawa 239, Japan. W Coast & Alaska Tsunami Warning Ctr, Palmer, AK 99645 USA. RP Tsuboi, S (reprint author), Natl Def Acad, Dept Geosci, 1-10-20 Hashirimizu, Yokosuka, Kanagawa 239, Japan. NR 2 TC 23 Z9 26 U1 0 U2 1 PU SEISMOLOGICAL SOC AMER PI EL CERRITO PA PLAZA PROFESSIONAL BLDG, SUITE 201, EL CERRITO, CA 94530 USA SN 0037-1106 J9 B SEISMOL SOC AM JI Bull. Seismol. Soc. Amer. PD OCT PY 1999 VL 89 IS 5 BP 1345 EP 1351 PG 7 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 256HP UT WOS:000083720100015 ER PT J AU Parrish, R AF Parrish, R TI Marine reserves for fisheries management: Why not SO CALIFORNIA COOPERATIVE OCEANIC FISHERIES INVESTIGATIONS REPORTS LA English DT Article ID PACIFIC; CLIMATE AB Marine reserves have recently become a politically correct way of viewing the management of marine resources. Much of the reason for this is due to the depressed state of many of the populations that have been the mainstay of both. commercial and recreational marine fisheries. The apparent failure of past management has led to a headlong rush for a paradigm shift. Marine reserves that occupy no more than about 5% of the productive habitat call provide sites for research, for monitoring natural variability and for preserving habitat and diversity for heritage purposes. But the case for large marine reserves for fisheries management purposes has not yet been adequately made. The few available modeling studies suggest that for fisheries management purposes, marine reserves need to be on the order of 50% of the productive habitat. Analyses presented here suggest that, with reserves this large, current yields can be obtained only with a considerable increase in total fishing effort and a very large increase in the mortality rates in areas open to fishing. This implies a large increase in the trawling rate, and probably associated ecological damage, in the exploited area. Even if it were desirable to manage an individual species with large marine reserves, the concept breaks down when applied to the West Coast trawl fishery, which is based on many species, each with a different habitat. A marine reserve established for overexploited groundfish provides little real protection for migratory species such as Pacific hake, but may greatly increase the cost of fishing for these species. C1 Natl Marine Fisheries Serv, Pacific Fisheries Environm Lab, Pacific Grove, CA 93950 USA. RP Parrish, R (reprint author), Natl Marine Fisheries Serv, Pacific Fisheries Environm Lab, 1352 Lighthouse Ave, Pacific Grove, CA 93950 USA. NR 19 TC 34 Z9 35 U1 0 U2 9 PU SCRIPPS INST OCEANOGRAPHY PI LA JOLLA PA A-003, LA JOLLA, CA 92093 USA SN 0575-3317 J9 CAL COOP OCEAN FISH JI Calif. Coop. Ocean. Fish. Invest. Rep. PD OCT PY 1999 VL 40 BP 77 EP 86 PG 10 WC Fisheries SC Fisheries GA 283AQ UT WOS:000085254300009 ER PT J AU Thomson, CJ AF Thomson, CJ TI Economic and management implications of no-take reserves: An application to Sebastes rockfish in California SO CALIFORNIA COOPERATIVE OCEANIC FISHERIES INVESTIGATIONS REPORTS LA English DT Article ID MARINE AB This paper presents some of the economic and management issues likely to arise if a no-take reserve is designed to protect and manage rockfish in California. These issues include equity matters associated with location of the reserve, implications for major sectors of the rockfish fishery and possible external effects on fsh stocks and fisheries outside the reserve area. These issues are described in the context of the current management regime and recent trends in the fishery. Particular attention, is paid to two fishery sectors-groundfish trawlers and commercial passenger fishing vessels-whose logbook data provide detailed information about the area of harvest. Recommendations are made regarding the need to define objectives, address allocative issues and external effects, accommodate scientific uncertainties, and consider reserves in combination with more conventional management techniques. C1 NOAA, Natl Marine Fisheries Serv, SW Fisheries Sci Ctr, Santa Cruz Tiburon Lab, Tiburon, CA 94920 USA. RP Thomson, CJ (reprint author), NOAA, Natl Marine Fisheries Serv, SW Fisheries Sci Ctr, Santa Cruz Tiburon Lab, 3150 Paradise Dr, Tiburon, CA 94920 USA. NR 16 TC 1 Z9 1 U1 0 U2 2 PU SCRIPPS INST OCEANOGRAPHY PI LA JOLLA PA A-003, LA JOLLA, CA 92093 USA SN 0575-3317 J9 CAL COOP OCEAN FISH JI Calif. Coop. Ocean. Fish. Invest. Rep. PD OCT PY 1999 VL 40 BP 107 EP 117 PG 11 WC Fisheries SC Fisheries GA 283AQ UT WOS:000085254300013 ER PT J AU Watson, W Charter, RL Moser, HG Vetter, RD Ambrose, DA Charter, SR Robertson, LL Sandknop, EM Lynn, EA Stannard, J AF Watson, W Charter, RL Moser, HG Vetter, RD Ambrose, DA Charter, SR Robertson, LL Sandknop, EM Lynn, EA Stannard, J TI Fine-scale distributions of planktonic fish eggs in the vicinities of Big Sycamore Canyon and Vandenberg Ecological Reserves, and Anacapa and San Miguel Islands, California SO CALIFORNIA COOPERATIVE OCEANIC FISHERIES INVESTIGATIONS REPORTS LA English DT Article ID SOUTHERN AB Nearshore ichthyoplankton surveys were conducted during late winter and early summer 1998, at four sites in southern California: Big Sycamore Canyon and Vandenberg Ecological Reserves, and Anacapa and San Miguel Islands. A continuous underway fish egg sampler (CUFES) was used to sample along each of three or four transect lines oriented alongshore and spaced at about 0.8 km or 1.6 km intervals offshore, and a bongo net nas towed vertically through the water column at a series of stations spaced about 0.8 km or 1.6 km apart on each line. A total of 41 fish egg taxa and an unidentified fish egg category were collected: 30 taxa in winter and 29 in summer. Winter fish egg collections were dominated by northern anchovy; California halibut, speckled sand-dab, white croaker, and Pacific hake eggs also were common. Summer egg catches were more evenly distributed over several taxa, primarily senorita, California sheep-head, California barracuda plus white seabass, and speckled sanddab, as well as unidentified eggs. Collections of eggs in early developmental stages suggested that many taxa spawned at night. Senorita spawned during the day, California sheephead probably spawned primarily during the day, and California halibut may have begun spawning during the afternoon and continued into the evening. Both frequency of occurrence and abundance of eggs tended to be higher inshore and were much reduced on the most seaward line for the more common shorefrsh taxa. White croaker and California sheephead probably spawned primarily shoreward of about the 30 m isobath, and speckled sanddab and senorita shoreward of about the 60 m isobath. California halibut apparently spawned primarily between about the 40 and 60 m isobaths, and California barracuda and white seabass spawned over a broader depth range, about 45-90 m. Abundances of California halibut and white croaker eggs were highest at the Big Sycamore Canyon site, while the islands, especially Anacapa Island, were important sites far California sheephead, senorita, California barracuda, and white seabass spawning. The CUFES proved to be an effective sampler for fine-scale distributions of planktonic fish eggs, but may inadequately sample taxa or developmental stages whose vertical distributions are centered above or below its intake depth. Use of another sampler that covers the entire vertical range of the taxa of interest is a necessary adjunct to CUFES sampling. C1 NOAA, Natl Marine Fisheries Serv, SW Fisheries Sci Ctr, La Jolla, CA 92038 USA. RP Watson, W (reprint author), NOAA, Natl Marine Fisheries Serv, SW Fisheries Sci Ctr, POB 271, La Jolla, CA 92038 USA. NR 19 TC 8 Z9 8 U1 0 U2 2 PU SCRIPPS INST OCEANOGRAPHY PI LA JOLLA PA A-003, LA JOLLA, CA 92093 USA SN 0575-3317 J9 CAL COOP OCEAN FISH JI Calif. Coop. Ocean. Fish. Invest. Rep. PD OCT PY 1999 VL 40 BP 128 EP 153 PG 26 WC Fisheries SC Fisheries GA 283AQ UT WOS:000085254300015 ER PT J AU Butler, J Fuller, D Yaremko, M AF Butler, J Fuller, D Yaremko, M TI Age and growth of market squid (Loligo opalescens) off California during 1998 SO CALIFORNIA COOPERATIVE OCEANIC FISHERIES INVESTIGATIONS REPORTS LA English DT Article ID FISH OTOLITHS; FINNED SQUID; STATOLITH; CEPHALOPODA; INCREMENTS; MATURATION; LOLIGINIDAE; LARVAL AB Daily increments in statoliths indicate that both male and female market squid (Loligo opalescens) mature as early as 6 months after hatching. An analysis of 192 statolith pairs revealed maximum ages of 238 days for females and 243 days for males during 1998. These ages indicate that market squid may be a semiannual species and that spawning peaks may occur twice in a calendar year. Growth rate derived from size-at-age information was best described by a linear equation, with no difference between sexes. C1 Natl Marine Fisheries Serv, SW Fisheries Sci Ctr, La Jolla, CA 92038 USA. RP Butler, J (reprint author), Natl Marine Fisheries Serv, SW Fisheries Sci Ctr, POB 271, La Jolla, CA 92038 USA. NR 26 TC 27 Z9 28 U1 0 U2 6 PU SCRIPPS INST OCEANOGRAPHY PI LA JOLLA PA A-003, LA JOLLA, CA 92093 USA SN 0575-3317 J9 CAL COOP OCEAN FISH JI Calif. Coop. Ocean. Fish. Invest. Rep. PD OCT PY 1999 VL 40 BP 191 EP 195 PG 5 WC Fisheries SC Fisheries GA 283AQ UT WOS:000085254300021 ER PT J AU Lowry, MS Carretta, JV AF Lowry, MS Carretta, JV TI Market squid (Loligo opalescens) in the diet of California sea lions (Zalophus californianus) in southern California (1981-1995) SO CALIFORNIA COOPERATIVE OCEANIC FISHERIES INVESTIGATIONS REPORTS LA English DT Article ID ISLAND AB California sea Lion (Zalophus californianus) seat and spewing samples collected at three rookeries in southern California during 1981-95 were used to determine how sea lions utilized the market squid (Loligo opalescens) resource. The samples revealed that market squid is one of the most important prey of sea lions in southern California, occurring in 35% to 44% of scat samples from San Nicolas Island (SNI), San Clemente Island (SCI), and Santa Barbara Island (SBI). It is eaten by sea Lions throughout the year, but most often during fall and winter, and patterns suggest periods of high and low consumption associated with prevailing oceanographic conditions and, possibly, with squid abundance and movements. Percent frequency of occurrence values for market squid in seat samples collected seasonally from SNI were positively correlated with those from SCI (r = 0.78), and samples collected during summer at SBI were positively correlated with summer samples front SCI (r = 0.82) and SNI (r = 0.85). Landings of market squid at ports in southern California and percent occurrence Values of market squid in seat samples collected seasonally were positively correlated for SNI (r = 0.66) and SCI (r = 0.74), but not for summer samples from SBI (r = 0.25). Sea lions eat squid with dorsal mantle lengths h-om 10 to 235 mm (mean = 227 mm). Significant seasonal, annual, and interisland differences (P < 0.001) were found in the size of squid consumed by sea lions. Significant differences (P < 0.001) were found in size of squid between seats and spewings, and between individual samples. C1 NOAA, Natl Marine Fisheries Serv, SW Fisheries Sci Ctr, La Jolla, CA 92038 USA. RP Lowry, MS (reprint author), NOAA, Natl Marine Fisheries Serv, SW Fisheries Sci Ctr, POB 271, La Jolla, CA 92038 USA. NR 27 TC 30 Z9 32 U1 0 U2 2 PU SCRIPPS INST OCEANOGRAPHY PI LA JOLLA PA A-003, LA JOLLA, CA 92093 USA SN 0575-3317 J9 CAL COOP OCEAN FISH JI Calif. Coop. Ocean. Fish. Invest. Rep. PD OCT PY 1999 VL 40 BP 196 EP 207 PG 12 WC Fisheries SC Fisheries GA 283AQ UT WOS:000085254300022 ER PT J AU Omair, M Vanderploeg, HA Jude, DJ Fahnenstiel, GL AF Omair, M Vanderploeg, HA Jude, DJ Fahnenstiel, GL TI First observations of tumor-like abnormalities (exophytic lesions) on Lake Michigan zooplankton SO CANADIAN JOURNAL OF FISHERIES AND AQUATIC SCIENCES LA English DT Article AB Tumor-like abnormalities (exophytic lesions) were found on a variety of planktonic calanoid copepods and cladocerans (Diaptomus spp., Epischura lacustris, Limnocalanus macrurus, Polyphemus pediculus, Diaphanosoma sp., and Daphnia galeata mendotae) collected from inshore (3-m depth contour) and offshore (100- to 110-m depth contours) stations of eastern Lake Michigan. The abnormalities, which were quite large relative to animal size and variable in shape, are documented in photographs. Abnormality incidences among species ranged between 0 and 72%. Predatory species of calanoids and cladocerans had higher incidences of tumors than herbivorous species. The abnormalities on some copepods were very similar to cysts described for calanoid copepods in Lago Maggiore, Italy, which like Lake Michigan is undergoing oligotrophication. The recent appearance of the lesions in Europe and North America may indicate an emerging global phenomenon that has a common cause. C1 Univ Michigan, Ctr Great Lakes & Aquat Sci, Ann Arbor, MI 48109 USA. NOAA, Great Lakes Environm Res Lab, Ann Arbor, MI 48105 USA. RP Omair, M (reprint author), Univ Michigan, Ctr Great Lakes & Aquat Sci, 2021 CC Little Bldg,501 E Univ Ave, Ann Arbor, MI 48109 USA. RI Mensinger, Allen/B-7349-2013; OI Vanderploeg, Henry/0000-0003-1358-8475 NR 12 TC 9 Z9 12 U1 0 U2 2 PU NATL RESEARCH COUNCIL CANADA PI OTTAWA PA RESEARCH JOURNALS, MONTREAL RD, OTTAWA, ONTARIO K1A 0R6, CANADA SN 0706-652X J9 CAN J FISH AQUAT SCI JI Can. J. Fish. Aquat. Sci. PD OCT PY 1999 VL 56 IS 10 BP 1711 EP 1715 DI 10.1139/cjfas-56-10-1711 PG 5 WC Fisheries; Marine & Freshwater Biology SC Fisheries; Marine & Freshwater Biology GA 252GX UT WOS:000083494700001 ER PT J AU Bentz, DP Garboczi, EJ Haecker, CJ Jensen, OM AF Bentz, DP Garboczi, EJ Haecker, CJ Jensen, OM TI Effects of cement particle size distribution on performance properties of Portland cement-based materials SO CEMENT AND CONCRETE RESEARCH LA English DT Article DE cement paste; hydration; modeling; particle size distribution; transport properties ID MICROSTRUCTURAL MODEL; COMPUTER-SIMULATION; SILICA FUME; HYDRATION; PASTE; EVOLUTION; SHRINKAGE AB The original size, spatial distribution, and composition of Portland cement particles have a large influence on hydration kinetics, microstructure development, and ultimate properties of cement-based materials. In this paper, the effects of cement particle size distribution on a variety of performance properties are explored via computer simulation and a few experimental studies. Properties examined include setting time, heat release, capillary porosity percolation, diffusivity, chemical shrinkage, autogenous shrinkage, internal relative humidity evolution, and interfacial transition zone microstructure. The effects of flocculation and dispersion of the cement particles in the starting microstructures on resultant properties are also briefly evaluated. The computer simulations are conducted using two cement particle size distributions that bound those commonly in use today and three different water-to-cement ratios: 0.5, 0.3, and 0.246. For lower water-to-cement ratio systems, the use of coarser cements may offer equivalent or superior performance, as well as reducing production costs for the manufacturer. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Natl Inst Stand & Technol, Bldg & Fire Res Lab, Gaithersburg, MD 20899 USA. Wilhelm Dyckerhoff Inst, Wiesbaden, Germany. Tech Univ Denmark, DK-2800 Lyngby, Denmark. RP Bentz, DP (reprint author), Natl Inst Stand & Technol, Bldg & Fire Res Lab, Bldg 226 Room B-350, Gaithersburg, MD 20899 USA. NR 30 TC 112 Z9 120 U1 7 U2 46 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0008-8846 J9 CEMENT CONCRETE RES JI Cem. Concr. Res. PD OCT PY 1999 VL 29 IS 10 BP 1663 EP 1671 DI 10.1016/S0008-8846(99)00163-5 PG 9 WC Construction & Building Technology; Materials Science, Multidisciplinary SC Construction & Building Technology; Materials Science GA 255DJ UT WOS:000083654000019 ER PT J AU Johnson, GM Reisner, BA Tripathi, A Corbin, DR Toby, BH Parise, JB AF Johnson, GM Reisner, BA Tripathi, A Corbin, DR Toby, BH Parise, JB TI Flexibility and cation distribution upon lithium exchange of aluminosilicate and aluminogermanate materials with the RHO topology SO CHEMISTRY OF MATERIALS LA English DT Article ID NEUTRON POWDER DIFFRACTION; CUBIC SODALITE STRUCTURE; ZEOLITE-RHO; PHYSICAL CHARACTERIZATION; CRYSTAL-STRUCTURE; X-RAY; FRAMEWORK; DISTORTIONS; DEHYDRATION; CATALYSTS AB The influence of lithium substitution on the structure of aluminosilicate (AlSi) and aluminogermanate (AlGe) materials with the zeolite RHO topology has been examined. The exchanged materials were dehydrated and structurally characterized via Rietveld refinement using neutron powder diffraction data. Li-AlSi-rho crystallizes in the space group I (4) over bar 3m with a 14.2609(3) Angstrom, whereas Li-AlGe-rho adopts the space group I23 with a = 14.2926(5) Angstrom. The extraframework cations reside in their expected positions in Li-AlSi-rho: cesium is found in the double eight ring (D8R) and lithium is observed only in the single six ring (S6R). In Li-AlGe-rho, lithium resides in both the single six ring and the single eight rings (S8R) while cesium is located exclusively in the S6R. Although these cation positions are unusual for materials with the RHO topology, they are a response to the framework distortions introduced by ion exchange and dehydration. The extraframework cation positions correspond to those that best satisfy the coordination requirements of each cation. C1 SUNY Stony Brook, Dept Geosci, Stony Brook, NY 11794 USA. SUNY Stony Brook, Dept Chem, Stony Brook, NY 11794 USA. Dupont Co, Cent Res & Dev, Expt Stn, Wilmington, DE 19880 USA. Natl Inst Stand & Technol, Ctr Neutron Res, Gaithersburg, MD 20899 USA. RP Reisner, BA (reprint author), SUNY Stony Brook, Dept Geosci, Stony Brook, NY 11794 USA. RI Toby, Brian/F-3176-2013; OI Toby, Brian/0000-0001-8793-8285; Reisner, Barbara/0000-0003-3160-0351 NR 46 TC 22 Z9 22 U1 2 U2 18 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 OCT PY 1999 VL 11 IS 10 BP 2780 EP 2787 DI 10.1021/cm990179g PG 8 WC Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA 248DY UT WOS:000083261100023 ER PT J AU Smith, MD Stalick, JK zur Loye, HC AF Smith, MD Stalick, JK zur Loye, HC TI Sr3PbNiO6: Trigonal prismatic lead in a novel inverse K4CdCl6-type pseudo-one-dimensional oxide SO CHEMISTRY OF MATERIALS LA English DT Article ID MAGNETIC-PROPERTIES; CRYSTAL-STRUCTURE; COPPER-OXIDE; SR4PTO6 TYPE; COMPOUND; RH; COORDINATION; FAMILY; ZINC; IR AB The new one-dimensional oxide Sr3PbNiO6 contains the first reported example of lead in the 2H hexagonal perovskite-related family of oxides with the formula A(3)A'BO6. The compound can be prepared by conventional high-temperature synthetic routes, or single crystals can be grown from a sodium chloride flux. Sr3PbNiO6 adopts the K4CdCl6 structure type (R (3) over bar c; a = 9.7041(1) Angstrom, c = 11.3128(1) Angstrom, V = 922.59(1) Angstrom(3), Z = 6), comprised of face-sharing polyhedral (1)(infinity)[PbO6/2NiO6/2] chains surrounded by six (1)(infinity)[Sr2+] chains, both running along [001]. Pb4+ occupies a slightly distorted trigonal prismatic coordination environment previously unobserved in oxides; Ni2+ is octahedrally coordinated. The cation distribution in the polyhedral chains (+4 cation in the trigonal prismatic site, +2 in the octahedral site) is the inverse of that normally observed in the A(3)A'BO6 oxides. Sr3PbNiO6 is a Curie-Weiss paramagnet with an antiferromagnetic transition at T-N = 6 K. Complementary single-crystal and neutron diffraction structure determinations, thermogravimetric analysis, scanning electron microscopy, and magnetic susceptibility measurements are reported. C1 Univ S Carolina, Dept Chem & Biochem, Columbia, SC 29208 USA. Natl Inst Stand & Technol, NIST Ctr Neutron Res, Gaithersburg, MD 20899 USA. RP zur Loye, HC (reprint author), Univ S Carolina, Dept Chem & Biochem, Columbia, SC 29208 USA. OI zur Loye, Hans-Conrad/0000-0001-7351-9098 NR 44 TC 31 Z9 31 U1 1 U2 2 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 OCT PY 1999 VL 11 IS 10 BP 2984 EP 2988 DI 10.1021/cm990360p PG 5 WC Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA 248DY UT WOS:000083261100048 ER PT J AU Waliser, DE Shi, Z Lanzante, JR Oort, AH AF Waliser, DE Shi, Z Lanzante, JR Oort, AH TI The Hadley circulation: assessing NCEP/NCAR reanalysis and sparse in situ estimates SO CLIMATE DYNAMICS LA English DT Article ID STEADY-STATE MODELS; BASIC STATE; CLIMATE; ATMOSPHERE; INSTABILITY; OCEAN AB We present a comparison of the zonal mean meridional circulations derived from monthly in situ data (i.e. radiosondes and ship reports) and from the NCEP/NCAR reanalysis product. To facilitate the interpretation of the results, a third estimate of the mean meridional circulation is produced by subsampling the reanalysis at the locations where radiosonde and surface ship data are available for the in situ calculation. This third estimate, known as the subsampled estimate, is compared to the complete reanalysis estimate to assess biases in conventional, in situ estimates of the Hadley circulation associated with the sparseness of the data sources (i.e,, radiosonde network). The subsampled estimate is also compared to the in situ estimate to assess the biases introduced into the reanalysis product by the numerical model, initialization process and/or indirect data sources such as satellite retrievals. The comparisons suggest that a number of qualitative differences between the in situ and reanalysis estimates are mainly associated with the sparse sampling and simplified interpolation schemes associated with in situ estimates. These differences include: (1) a southern Hadley cell. that consistently extends up to 200 hPa in the reanalysis, whereas the bulk of the circulation for the in Situ and subsampled estimates tends to be confined to the lower half of the troposphere, (2) more well-defined and consistent poleward limits of the Hadley cells in the reanalysis compared to the in-situ and subsampled estimates, and (3) considerably less variability in magnitude and latitudinal extent of the Ferrel cells and southern polar cell exhibited in the reanalysis estimate compared to the in situ and subsampled estimates. Quantitative comparison shows that the subsampled estimate, relative to the reanalysis estimate, produces a stronger northern Hadley cell (similar to 20%), a weaker southern Hadley cell ( similar to 20-60%), and weaker Ferrel cells in both hemispheres. These differences stem from poorly measured oceanic regions which necessitate significant interpolation over broad regions. Moreover, they help to pinpoint specific shortcomings in the present and previous in situ estimates of the Hadley circulation. Comparisons between the subsampled and in situ estimates suggest that the subsampled estimate produces a slightly stronger Hadley circulation in both hemispheres, with the relative differences in some seasons as large as 20-30%. These differences suggest that the mean meridional circulation associated with the NCEP/NCAR reanalysis is more energetic than observations suggest. Examination of ENSO-related changes to the Hadley circulation suggest that the in situ and subsampled estimates significantly overestimate the effects of ENSO on the Hadley circulation due to the reliance on sparsely distributed data. While all three estimates capture the large-scale region of low-level equatorial convergence near the dateline that occurs during El Nine, the in situ and subsampled estimates fail to effectively reproduce the large-scale areas of equatorial mass divergence to the west and east of this convergence area, leading to an overestimate of the effects of ENSO on the zonal mean circulation. C1 SUNY Stony Brook, Inst Terr & Planetary Atmospheres, Stony Brook, NY 11794 USA. Princeton Univ, Geophys Fluid Dynam Lab, Princeton, NJ 08542 USA. RP Waliser, DE (reprint author), SUNY Stony Brook, Inst Terr & Planetary Atmospheres, Stony Brook, NY 11794 USA. NR 32 TC 51 Z9 53 U1 0 U2 3 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0930-7575 J9 CLIM DYNAM JI Clim. Dyn. PD OCT PY 1999 VL 15 IS 10 BP 719 EP 735 DI 10.1007/s003820050312 PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 245ZL UT WOS:000083138600002 ER PT J AU Delworth, TL Mahlman, JD Knutson, TR AF Delworth, TL Mahlman, JD Knutson, TR TI Changes in heat index associated with CO2-induced global warming SO CLIMATIC CHANGE LA English DT Article ID APPARENT TEMPERATURE; HEALTH; MODEL AB Changes in Heat Index (a combined measure of temperature and humidity) associated with global warming are evaluated based on the output from four extended integrations of the GFDL coupled ocean-atmosphere climate model. The four integrations are: a control with constant levels of atmospheric carbon dioxide (CO2), a second integration in which an estimate of the combined radiative forcing of greenhouse gases and sulfate aerosols over the period 1765-2065 is used to force the model, and a third (fourth) integration in which atmospheric CO2 increases at the rate of 1% per year to double (quadruple) its initial value, and is held constant thereafter. While the spatial patterns of the changes in Heat Index are largely determined by the changes in surface air temperature, increases in atmospheric moisture can substantially amplify the changes in Heat Index over regions which are warm and humid in the Control integration. The regions most prone to this effect include humid regions of the Tropics and summer hemisphere extra-tropics, including the southeastern United States, India, southeast Asia and northern Australia. C1 NOAA, Geophys Fluid Dynam Lab, Princeton, NJ 08542 USA. RP Delworth, TL (reprint author), NOAA, Geophys Fluid Dynam Lab, Princeton, NJ 08542 USA. RI Delworth, Thomas/C-5191-2014 NR 11 TC 25 Z9 25 U1 1 U2 6 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0165-0009 J9 CLIMATIC CHANGE JI Clim. Change PD OCT PY 1999 VL 43 IS 2 BP 369 EP 386 DI 10.1023/A:1005463917086 PG 18 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA 237PP UT WOS:000082665500002 ER PT J AU Mulholland, GW Mountain, RD AF Mulholland, GW Mountain, RD TI Coupled dipole calculation of extinction coefficient and polarization ratio for smoke agglomerates SO COMBUSTION AND FLAME LA English DT Article ID TURBULENT-DIFFUSION FLAMES; OPTICAL-PROPERTIES; LIGHT-SCATTERING; REFRACTIVE-INDEXES; SOOT; ABSORPTION; MORPHOLOGY; PARTICLES; AGGREGATE; AEROSOLS AB The mass specific extinction coefficient and the polarization ratio at 90 degrees of simulated smoke agglomerates are computed for clusters with 3 to 1390 primary spheres and for size parameter from 0.05 to 0.6 using the coupled electric and magnetic dipole (CEMD) method. For the size parameter range of interest for postflame smoke, the specific extinction coefficient computed by CEMD is 21% to 36% greater than Rayleigh prediction, and for this size range for clusters with 100 to 1000 primary spheres, the range in the specific extinction coefficient is about 12%. Agreement between measured and predicted specific extinction coefficient would require selection of a refractive index outside the range of values widely used by the combustion community. The polarization ratio at 90 degrees is found to be a monotonic function of primary sphere size and relatively independent of agglomerate size. Comparison with the limited experimental results indicates potential For polarization ratio as a diagnostic for primary sphere size. (C) 1999 by The Combustion Institute. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Mulholland, GW (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NR 36 TC 28 Z9 28 U1 2 U2 3 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 USA SN 0010-2180 J9 COMBUST FLAME JI Combust. Flame PD OCT PY 1999 VL 119 IS 1-2 BP 56 EP 68 DI 10.1016/S0010-2180(99)00035-8 PG 13 WC Thermodynamics; Energy & Fuels; Engineering, Multidisciplinary; Engineering, Chemical; Engineering, Mechanical SC Thermodynamics; Energy & Fuels; Engineering GA 228HB UT WOS:000082130100004 ER PT J AU Gerber, LR DeMaster, DP AF Gerber, LR DeMaster, DP TI A quantitative approach to endangered species act classification of long-lived vertebrates: Application to the North Pacific humpback whale SO CONSERVATION BIOLOGY LA English DT Article ID MEGAPTERA-NOVAEANGLIAE; SEXUAL MATURITY; PARAMETERS; CALIFORNIA; ATTAINMENT; EXTINCTION AB The US. Endangered Species Act (ESA) mandates that recovery plans include specific criteria to determine when a species should be removed from the List of Endangered and Threatened Wildlife. To meet this mandate, we developed a new approach to determining classification criteria for long-lived vertebrates The key idea is that endangerment depends on two critical aspects of a population: population size and trends in population size due to intrinsic variability in population growth rates. The way to combine these features is to identify a population size and range of population growth rates (where lambda denotes the annual multiplicative rate of change of a population) above which there is a negligible probability of extinction. To do so, (1) information on the current population size and its variance is specified; (2) available information on vital rates or changes in abundance over time is used to generate a probability distribution for the population's lambda; (3) the lower fifth percentile value for lambda (denoted as lambda((0.05)))is obtained from the frequency distribution of lambda s and (4) if lambda((0.05)) is <1.0, a backwards population trajectory starting at 500 individuals for a period of 10 years is performed and the resulting population size is designated as the threshold for listing a species as endangered, or if lambda((0.05)) is greater than or equal to 1.0, the threshold for endangerment is set at 500 animals. A similar approach can be used to determine the threshold for listing a species as threatened under the ESA. We applied this approach to North Pacific humpback whales (Megaptera novaeangliae) and used Monte Carlo simulations to produce a frequency distribution of lambda s for the whales under three different scenarios. Using lambda((0.05)) it was determined that the best estimates of current abundance for the central population of North Pacific humpback whales were larger than the estimated threshold for endangered status but less than the estimated threshold for threatened status if accepted by the responsible management agency this analysis would be consistent with a recommendation to downlist the central stock of humpback whales to a status of threatened, whereas the status of eastern and western stocks would remain endangered. C1 Univ Washington, Washington Cooperat Fish & Wildlife Unit, Sch Fisheries, Seattle, WA 98195 USA. Alaska Fisheries Sci Ctr, Natl Marine Mammal Lab, Seattle, WA 98115 USA. RP Univ Calif Santa Barbara, Natl Ctr Ecol Analy & Synth, 735 State St,Suite 300, Santa Barbara, CA 93101 USA. EM gerber@nceas.ucsb.edu; douglas.demaster@noaa.gov NR 35 TC 21 Z9 22 U1 4 U2 12 PU WILEY-BLACKWELL PI HOBOKEN PA 111 RIVER ST, HOBOKEN 07030-5774, NJ USA SN 0888-8892 EI 1523-1739 J9 CONSERV BIOL JI Conserv. Biol. PD OCT PY 1999 VL 13 IS 5 BP 1203 EP 1214 DI 10.1046/j.1523-1739.1999.98277.x PG 12 WC Biodiversity Conservation; Ecology; Environmental Sciences SC Biodiversity & Conservation; Environmental Sciences & Ecology GA 240JD UT WOS:000082821400032 ER PT J AU Gerber, LR DeMaster, DP Kareiva, PM AF Gerber, LR DeMaster, DP Kareiva, PM TI Gray whales and the value of monitoring data in implementing the US Endangered Species Act SO CONSERVATION BIOLOGY LA English DT Article AB Many scientists lament the absence of data for endangered species and argue that mno-e funds should be spent acquiring basic information about population trends Using 19 years of abundance estimates for the eastern North Pacific gray whale (Eschrichtius robustus), we sampled subsets of the original survey data to identify the number of years of data required to remove the population from the U;S. Endangered Species Act's (ESA) list of endangered and threatened wildlife. I;or any given duration of monitoring, we selected all possible combinations of consecutive counts. To incorporate variability in growth rates, we extracted a maximum likelihood estimator of growth rate and confidence interval about that growth rate on the assumption that the population changes can be approximated by a simple diffusion process with drift. We then applied a new approach to determine ESA status for each subset of survey data and found that a quantitative decision to delist is unambiguously supported by 11 years of data but is precariously uncertain with fewer than 10 years of data. The data needed to produce an unequivocal decision to delist gray whales cost the National Marine Fisheries Service an estimated U.S. $660,000 a surprisingly modest expense given the fact that delisting can greatly simplify regulatory constraints This example highlights the value of population monitoring in administering the ESA and provides a compelling example of the utility of such information in identifying both imperiled and recovered species. The economic value of such data is that they provide the foundation for delisting, which could ultimately save much more money than the collection of the data would ever cost. C1 Univ Calif Santa Barbara, Natl Ctr Ecol Analy & Synth, Santa Barbara, CA 93101 USA. NOAA, Natl Marine Mammal Lab, Alaska Fisheries Sci Ctr, Seattle, WA 98115 USA. Sch Fisheries, Washington Cooperat Fish & Wildlife Res Unit, Seattle, WA 98195 USA. RP Gerber, LR (reprint author), Univ Calif Santa Barbara, Natl Ctr Ecol Analy & Synth, 735 State St,Suite 300, Santa Barbara, CA 93101 USA. NR 14 TC 35 Z9 36 U1 3 U2 7 PU BLACKWELL SCIENCE INC PI MALDEN PA 350 MAIN ST, MALDEN, MA 02148 USA SN 0888-8892 J9 CONSERV BIOL JI Conserv. Biol. PD OCT PY 1999 VL 13 IS 5 BP 1215 EP 1219 DI 10.1046/j.1523-1739.1999.98466.x PG 5 WC Biodiversity Conservation; Ecology; Environmental Sciences SC Biodiversity & Conservation; Environmental Sciences & Ecology GA 240JD UT WOS:000082821400033 ER PT J AU Ruckelshaus, M Hartway, C Kareiva, P AF Ruckelshaus, M Hartway, C Kareiva, P TI Dispersal and landscape errors in spatially explicit population models: a reply SO CONSERVATION BIOLOGY LA English DT Editorial Material C1 Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, Seattle, WA 98112 USA. Univ Calif Santa Cruz, Dept Biol, Santa Cruz, CA 95064 USA. RP Ruckelshaus, M (reprint author), Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, 2725 Montlake Blvd E, Seattle, WA 98112 USA. NR 4 TC 19 Z9 19 U1 0 U2 9 PU BLACKWELL SCIENCE INC PI MALDEN PA 350 MAIN ST, MALDEN, MA 02148 USA SN 0888-8892 J9 CONSERV BIOL JI Conserv. Biol. PD OCT PY 1999 VL 13 IS 5 BP 1223 EP 1224 DI 10.1046/j.1523-1739.1999.99224.x PG 2 WC Biodiversity Conservation; Ecology; Environmental Sciences SC Biodiversity & Conservation; Environmental Sciences & Ecology GA 240JD UT WOS:000082821400035 ER PT J AU Kulin, S Castin, Y Ol'shanii, M Peik, E Saubamea, B Leduc, M Cohen-Tannoudji, C AF Kulin, S Castin, Y Ol'shanii, M Peik, E Saubamea, B Leduc, M Cohen-Tannoudji, C TI Exotic quantum dark states SO EUROPEAN PHYSICAL JOURNAL D LA English DT Article ID VELOCITY; ATOMS; DIMENSION AB We extend studies of velocity selective coherent population trapping to atoms having a J = 1 --> J = 0 transition. When placed in a two-dimensional laser field these atoms are optically pumped into different velocity selective nonabsorbing states. Each of these distinct energy eigenstates exhibits a unique entanglement between its internal and external degrees of freedom. We use a graphical method that makes easier the description of these states. We confirm our predictions experimentally. C1 Coll France, F-75231 Paris 05, France. Ecole Normale Super, Lab Kastler Brossel, F-75231 Paris, France. RP Castin, Y (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RI Olshanii, Maxim/M-2830-2013; OI Olshanii, Maxim/0000-0003-3629-6002; Peik, Ekkehard/0000-0001-6309-2975 NR 21 TC 2 Z9 2 U1 1 U2 6 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 1434-6060 J9 EUR PHYS J D JI Eur. Phys. J. D PD OCT-NOV PY 1999 VL 7 IS 3 BP 279 EP 284 DI 10.1007/s100530050570 PG 6 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 247NQ UT WOS:000083227200004 ER PT J AU Oates, CW Bondu, F Fox, RW Hollberg, L AF Oates, CW Bondu, F Fox, RW Hollberg, L TI A diode-laser optical frequency standard based on laser-cooled Ca atoms: Sub-kilohertz spectroscopy by optical shelving detection SO EUROPEAN PHYSICAL JOURNAL D LA English DT Article ID DOPPLER-FREE SPECTROSCOPY; INTERCOMBINATION TRANSITION; RAMSEY FRINGES; VAPOR-CELL; INTERFEROMETER; STRONTIUM; RESONANCE; PROSPECTS; CALCIUM; PHASE AB We report an optical frequency standard at 657 nm based on laser-cooled/trapped Ca atoms. The system consists of a novel, compact magneto-optic trap which uses 50 mW of frequency-doubled diode laser light at 423 nm and can trap > 10(7) Ca atoms in 20 ms. High resolution spectroscopy on this atomic sample using the narrow 657 nm intercombination line resolves linewidths (FWHM) as narrow as 400 Hz, the natural linewidth of the transition. The spectroscopic signal-to-noise ratio is enhanced by an order of magnitude with the implementation of a "shelving" detection scheme on the 423 nm transition. Our present apparatus achieves a fractional frequency instability of 5 x 10(-14) in 1 s with a potential atom shot-noise-limited performance of 10(-16) tau(-1/2) and excellent prospects for high accuracy. C1 Natl Inst Stand & Technol, Boulder, CO 80303 USA. RP Oates, CW (reprint author), Natl Inst Stand & Technol, Mail Stop 847-10,325 Broadway, Boulder, CO 80303 USA. RI Bondu, Francois/A-2071-2012 OI Bondu, Francois/0000-0001-6487-5197 NR 41 TC 110 Z9 111 U1 0 U2 7 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 1434-6060 J9 EUR PHYS J D JI Eur. Phys. J. D PD OCT-NOV PY 1999 VL 7 IS 3 BP 449 EP 460 DI 10.1007/s100530050589 PG 12 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 247NQ UT WOS:000083227200023 ER PT J AU Rush, JJ Udovic, TJ Berk, NF Richter, D Magerl, A AF Rush, JJ Udovic, TJ Berk, NF Richter, D Magerl, A TI Excited-state vibrational tunnel splitting of hydrogen trapped by nitrogen in niobium SO EUROPHYSICS LETTERS LA English DT Article ID TEMPERATURE-DEPENDENCE; QUANTUM DIFFUSION; C-AXIS; METALS; INTERSTITIALS; IMPURITIES; YTTRIUM; SYSTEMS; NB(OH)X AB High-resolution inelastic-neutron-scattering spectra of hydrogen trapped by interstitial nitrogen impurities in NbN(0.007)H(0.004) have been measured to study the vibrational lineshape of the broad 105 meV feature previously observed for NbN0.004H(o.003). The spectrum measured at 4.2 K exhibits clear evidence of a doublet that disappears at higher temperatures. We interpret this result as the first spectroscopic observation of excited-state tunnel splitting of light-atom (H) vibrations in a solid-state double-well potential. We also show that both the observed excited-state splitting of 4.0 +/- 0.3 meV and the previously measured ground-state splitting are well represented by a hardened-harmonic-well potential. C1 Natl Inst Stand & Technol, NIST Ctr Neutron Res, Gaithersburg, MD 20899 USA. Forschungszentrum Julich, Inst Festkorperforsch, D-52425 Julich, Germany. Univ Erlangen Nurnberg, Lehrstuhl Kristallog & Strukturphys, D-91054 Erlangen, Germany. RP Rush, JJ (reprint author), Natl Inst Stand & Technol, NIST Ctr Neutron Res, Gaithersburg, MD 20899 USA. RI Richter, Dieter/H-3701-2013; Magerl, Andreas/E-1797-2013 OI Richter, Dieter/0000-0003-0719-8470; NR 36 TC 6 Z9 6 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 0295-5075 J9 EUROPHYS LETT JI Europhys. Lett. PD OCT PY 1999 VL 48 IS 2 BP 187 EP 193 DI 10.1209/epl/i1999-00465-1 PG 7 WC Physics, Multidisciplinary SC Physics GA 247NK UT WOS:000083226700012 ER PT J AU Peacock, RD Reneke, PA Davis, WD Jones, WW AF Peacock, RD Reneke, PA Davis, WD Jones, WW TI Quantifying fire model evaluation using functional analysis SO FIRE SAFETY JOURNAL LA English DT Article AB Comparisons of predictive fire models with each other or with experimental data have been largely qualitative. By treating these time series curves as infinite-dimensional vectors, a branch of mathematics called functional analysis defines geometrically meaningful operations on the curves. This allows lengths, angles, and distance between two arbitrary curves to be defined and quantified. An introduction to the theory and tools provided by functional analysis is presented. Examples of the application of these tools to fire model evaluation are presented. Published by Elsevier Science Ltd. All rights reserved. C1 Natl Inst Stand & Technol, Bldg & Fire Res Lab, Gaithersburg, MD 20899 USA. RP Peacock, RD (reprint author), Natl Inst Stand & Technol, Bldg & Fire Res Lab, Gaithersburg, MD 20899 USA. NR 26 TC 29 Z9 32 U1 0 U2 2 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0379-7112 J9 FIRE SAFETY J JI Fire Saf. J. PD OCT PY 1999 VL 33 IS 3 BP 167 EP 184 DI 10.1016/S0379-7112(99)00029-6 PG 18 WC Engineering, Civil; Materials Science, Multidisciplinary SC Engineering; Materials Science GA 250ZB UT WOS:000083419200002 ER PT J AU Begg, GA Friedland, KD Pearce, JB AF Begg, GA Friedland, KD Pearce, JB TI Stock identification and its role in stock assessment and fisheries management: an overview SO FISHERIES RESEARCH LA English DT Article DE symposium; proceedings; stock identification; stock assessment; fisheries management AB A symposium on "Stock Identification - its Role in Stock Assessment and Fisheries Management" was held as part of the 128th annual meeting of the American Fisheries Society (AFS), Hartford, Connecticut, USA, 23-27 August 1998, to summarize the current state of knowledge of stock identification issues, problems and methodologies, as well as to identify future directions for stock identification research. With today's, growing emphasis on stock assessment, this symposium was a timely reminder of the need to identify fish stocks accurately, and the implications of stock identification for fisheries management. The symposium was structured into four general themes: (1) the stock concept; (2) genetic variation; (3) phenotypic variation; and (4) fisheries management. We review the presentations given in each theme session, which form the basis of the proceedings presented in this issue, as well as providing an overview of current issues and directions in stock identification research. We hope that the overall proceedings constitute a text helpful in these directions, useful in the classroom, laboratory, and field. (C) 1999 Elsevier Science B.V. All rights reserved. C1 NOAA, Natl Marine Fisheries Serv, NE Fisheries Sci Ctr, Woods Hole, MA 02543 USA. RP Begg, GA (reprint author), Marine Res Inst, POB 1390, IS-121 Reykjavik, Iceland. NR 8 TC 185 Z9 200 U1 8 U2 50 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0165-7836 J9 FISH RES JI Fish Res. PD OCT PY 1999 VL 43 IS 1-3 BP 1 EP 8 DI 10.1016/S0165-7836(99)00062-4 PG 8 WC Fisheries SC Fisheries GA 252MJ UT WOS:000083505000001 ER PT J AU Begg, GA Waldman, JR AF Begg, GA Waldman, JR TI An holistic approach to fish stock identification SO FISHERIES RESEARCH LA English DT Article DE stock; identification; population; discrimination; integration ID GULF-OF-MEXICO; STRIPED BASS; SCOMBEROMORUS-QUEENSLANDICUS; ELEMENTAL COMPOSITION; MITOCHONDRIAL-DNA; SPOTTED MACKEREL; SCHOOL MACKEREL; KING MACKEREL; WATERS; DISCRIMINATION AB The concept of the 'stock' is fundamental for both fisheries and endangered species management. We review different approaches used in identifying and classifying stocks and advocate that an holistic approach (e.g., involving a broad spectrum of complementary techniques) be used in future stock identification studies. Stock definitions should evolve as management requirements do and be re-evaluated when the need arises or when break-through technologies become available. (C) 1999 Elsevier Science B.V. All rights reserved. C1 NOAA, Natl Marine Fisheries Serv, NE Fisheries Sci Ctr, Woods Hole, MA 02543 USA. RP Begg, GA (reprint author), Marine Res Inst, POB 1390, IS-121 Reykjavik, Iceland. NR 76 TC 212 Z9 230 U1 5 U2 34 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0165-7836 J9 FISH RES JI Fish Res. PD OCT PY 1999 VL 43 IS 1-3 BP 35 EP 44 DI 10.1016/S0165-7836(99)00065-X PG 10 WC Fisheries SC Fisheries GA 252MJ UT WOS:000083505000004 ER PT J AU Cadrin, SX Friedland, KD AF Cadrin, SX Friedland, KD TI The utility of image processing techniques for morphometric analysis and stock identification SO FISHERIES RESEARCH LA English DT Article DE image analysis; stock identification; morphometrics ID SALMON SALMO-SALAR; EASTERN BERING SEA; ATLANTIC SALMON; BODY SHAPE; THREESPINE STICKLEBACK; ANADROMOUS SALMONIDS; ONCORHYNCHUS-KISUTCH; GEOGRAPHIC-VARIATION; COHO SALMON; POPULATIONS AB The development of image analysis systems has facilitated progress and diversification of morphometric methods and expands the potential for using morphometry as a tool for stock identification. Identifying intraspecific groups with different life histories according to shape variation has become more powerful, based on a review of published studies and our experiences with American lobster and Atlantic salmon. Traditional multivariate morphometrics, accounting for variation in size and shape, have successfully discriminated many fish stocks. However, traditional methods have been enhanced by image processing techniques, through better data collection, more effective descriptions of shape, and new analytical tools. Properly calibrated coordinates of morphometric locations, or 'landmarks', are generally more efficient and precise than manual distance measurements. 'Truss networks' of distances between landmark coordinates provide more comprehensive coverage of form for greater discriminating power. Image analysis systems also allow more advanced 'geometric morphometrics', which include outline methods and landmark methods. Unfortunately, few stock identification studies have applied outline methods, and landmark methods have not been used to discriminate fishery stocks. It appears that advanced geometric methods have not been commonly applied in fishery science, because ontogenetic interpretations are difficult. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Natl Marine Fisheries Serv, NE Fisheries Sci Ctr, Woods Hole, MA 02543 USA. RP Cadrin, SX (reprint author), Natl Marine Fisheries Serv, NE Fisheries Sci Ctr, Woods Hole, MA 02543 USA. RI Rohlf, F/A-8710-2008 NR 61 TC 77 Z9 94 U1 0 U2 21 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0165-7836 J9 FISH RES JI Fish Res. PD OCT PY 1999 VL 43 IS 1-3 BP 129 EP 139 DI 10.1016/S0165-7836(99)00070-3 PG 11 WC Fisheries SC Fisheries GA 252MJ UT WOS:000083505000009 ER PT J AU Begg, GA Hare, JA Sheehan, DD AF Begg, GA Hare, JA Sheehan, DD TI The role of life history parameters as indicators of stock structure SO FISHERIES RESEARCH LA English DT Article DE Atlantic cod; haddock; yellowtail flounder; oceanography; fisheries management ID HADDOCK MELANOGRAMMUS-AEGLEFINUS; GEORGES-BANK; LARVAL TRANSPORT; IDENTIFICATION; RECIRCULATION; CIRCULATION; FISH AB Vital population parameters, such as growth, survival, recruitment, reproduction, distribution, and abundance, are the consequences of life history modes to which fish stocks have evolved. Differences in these parameters have long been used to identify separate management stocks assuming that phenotypic variation is due to genotypic and environmental controls. However, few studies have examined the temporal stability of life history parameters, nor the mechanisms by which differences in these parameters between stocks are maintained. We examine the temporal and spatial stability of several life history parameters of Atlantic cod (Gadus morhua), haddock (Melanogrammus aeglefinus), and yellowtail flounder (Limanda ferruginea) in the northwest Atlantic Ocean to assess their utility for stock identification. Although significant temporal differences in vital rates were found within stocks, differences were generally maintained between stocks. Both genetic (biological) and oceanographic (physical) conditions play an integral role in maintaining stock structure. Although, the utility of vital life history parameters for stock identification may decrease with stock complexity and exploitation history, their applicability increases with the number of parameters examined. (C) 1999 Elsevier Science B.V. All rights reserved. C1 NOAA, Natl Marine Fisheries Serv, NE Fisheries Sci Ctr, Woods Hole, MA 02543 USA. RP Begg, GA (reprint author), NOAA, Natl Marine Fisheries Serv, NE Fisheries Sci Ctr, 166 Water St, Woods Hole, MA 02543 USA. NR 56 TC 62 Z9 68 U1 2 U2 14 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0165-7836 J9 FISH RES JI Fish Res. PD OCT PY 1999 VL 43 IS 1-3 BP 141 EP 163 DI 10.1016/S0165-7836(99)00071-5 PG 23 WC Fisheries SC Fisheries GA 252MJ UT WOS:000083505000010 ER PT J AU Buckel, JA Fogarty, MJ Conover, DO AF Buckel, JA Fogarty, MJ Conover, DO TI Foraging habits of bluefish, Pomatomus saltatrix, on the US east coast continental shelf SO FISHERY BULLETIN LA English DT Article ID THE-YEAR BLUEFISH; EARLY-LIFE-HISTORY; NEW-YORK BIGHT; JUVENILE BLUEFISH; BAY ANCHOVY; GROWTH; SIZE; PREY; ABUNDANCE; RATES AB After spending summer months in estuaries, spring- and summer-spawned young-of-the-year (YOY) bluefish, Pomatomus saltatrix, migrate out to continental shelf waters of the Mid-Atlantic Eight in early autumn. Adult bluefish are found on the continental shelf throughout summer and fall. Both juveniles and adults have high food consumption rates and are generally piscivorous. To determine principal prey types on the shelf, dietary analyses were performed on YOY and adult bluefish collected from National Marine Fisheries Service autumn bottom trawl surveys in 1994 and 1995. Both spring- and summer-spawned YOY bluefish diets were dominated by bay anchovy. However, the significantly larger size of the spring-spawned cohort was associated with the consumption of other prey species such as squid, butterfish, striped anchovy, and round herring. Summer-spawned bluefish were significantly smaller in 1995 than in 1994; diet and prey size comparisons suggest that body size had a dramatic influence on the amount of piscivorous feeding in the summer-spawned cohort. Adult bluefish diet was dominated by schooling species such as squid, butterfish, and clupeids. Cannibalism was virtually nonexistent. Daily ration estimates of YOY bluefish on the shelf(4-12% body wt/d) were similar to estuarine estimates in late summer. It is estimated that during the month of September, YOY bluefish in aggregate consumed 6.0 to 6.8 billion bay anchovies in 1994 and from 2.2 to 5.3 billion in 1995. The effect of this predatory loss on population dynamics of bay anchovy and the fish community on the continental shelf is unknown. C1 SUNY Stony Brook, Marine Sci Res Ctr, Stony Brook, NY 11794 USA. NOAA, Natl Marine Fisheries Serv, NE Fisheries Sci Ctr, Woods Hole, MA 02543 USA. RP Buckel, JA (reprint author), NOAA, Natl Marine Fisheries Serv, James J Howard Marine Sci Lab, 74 Magruder Rd, Highlands, NJ 07732 USA. EM jbuckel@sh.nmfs.gov NR 40 TC 53 Z9 56 U1 1 U2 10 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 EI 1937-4518 J9 FISH B-NOAA JI Fish. Bull. PD OCT PY 1999 VL 97 IS 4 BP 758 EP 775 PG 18 WC Fisheries SC Fisheries GA 256XX UT WOS:000083752700003 ER PT J AU Buckel, JA Fogarty, MJ Conover, DO AF Buckel, JA Fogarty, MJ Conover, DO TI Mutual prey of fish and humans: a comparison of biomass consumed by bluefish, Pomatomus saltatrix, with that harvested by fisheries SO FISHERY BULLETIN LA English DT Article ID THE-YEAR BLUEFISH; BIOENERGETICS MODELS; FOOD-CONSUMPTION; GROWTH; POPULATIONS; ENERGETICS; CONVERSION AB The bluefish, Pomatomus saltatrix, has long been considered a key predator on U.S. east coast fish species. Many of its prey species are also landed by humans, but no comparison of prey biomass harvested by bluefish versus fishermen has been attempted previously. We used data an growth, mortality, gross growth efficiency, and abundance to model the total prey consumption rate by bluefish at the population level. This estimate and previously published information on diet were used to calculate the biomass of individual resource species "harvested" by bluefish. The prey biomass consumed by bluefish annually along the U.S. Atlantic coast is equal to eight times the biomass of the bluefish population. Bluefish consume a much higher biomass of squid and butterfish than is currently harvested by commercial fisheries for these species. Bluefish consumption of Atlantic menhaden, however, was below the current fisheries landings for this species. For resource species that are shared with bluefish, our findings highlight the need for multi-species assessment and management. C1 SUNY Stony Brook, Marine Sci Res Ctr, Stony Brook, NY 11794 USA. NOAA, Natl Marine Fisheries Serv, NE Fisheries Sci Ctr, Woods Hole, MA 02543 USA. RP Buckel, JA (reprint author), NOAA, Natl Marine Fisheries Serv, James J Howard Marine Sci Lab, 74 Magruder Rd, Highlands, NJ 07732 USA. NR 26 TC 15 Z9 16 U1 0 U2 4 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 OCT PY 1999 VL 97 IS 4 BP 776 EP 785 PG 10 WC Fisheries SC Fisheries GA 256XX UT WOS:000083752700004 ER PT J AU Friedlander, AM Boehlert, GW Field, ME Mason, JE Gardner, JV Dartnell, P AF Friedlander, AM Boehlert, GW Field, ME Mason, JE Gardner, JV Dartnell, P TI Sidescan-sonar mapping of benthic trawl marks on the shelf and slope off Eureka, California SO FISHERY BULLETIN LA English DT Article ID CONTINENTAL-SHELF; NORTH-SEA; HABITAT; DISTURBANCE; FISHERIES; SEDIMENT; IMPACT; AREAS; RESUSPENSION; ECOSYSTEM AB The abundance and orientation of trawl marks was quantified over an extensive portion (>2700 km(2)) of the Eureka, California, outer shelf and slope, an important commercial bottom trawling ground for such high-value species as rockfish, sole, and sablefish. Fishing logbook data indicate that the entire reporting area was trawled about one and a half times on an average annual basis and that some areas were trawled over three times annually. High-resolution sidescansonar images of the study area revealed deep gouges on the seafloor, caused by heavy steel trawl doors that act to weigh down and spread open the bottom trawls. These trademarks are commonly oriented parallel to bathymetric contours and many could be traced for several kilometers. Trawl marks showed a quadratic relationship in relation to water depth, with the greatest number of trawl marks observed at similar to 400 m. There was a significant positive correlation between the number of trawl marks observed on the sidescan images and the number of annual trawl hours logged within reporting areas. This finding indicates that acoustic remote sensing is a promising independent approach to evaluate fishing effort on a scale consistent with commercial fishing activities. Bottom trawling gear is known to modify seafloor habitats by altering benthic habitat complexity and by removing or damaging infauna and sessile organisms. Identifying the extent of trawling in these areas may help determine the effects of this type of fishing gear on the benthos and develop indices of habitat disturbance caused by fishing activities. C1 NOAA, Natl Marine Fisheries Serv, SW Fisheries Sci Ctr, Pacific Fisheries Environm Lab, Pacific Grove, CA 93950 USA. US Geol Survey, Coastal & Marine Geol, Menlo Park, CA 94025 USA. RP Friedlander, AM (reprint author), Ocean Inst, Makapuu Point,41-202 Kalanianaole Highway, Waimanalo, HI 96795 USA. NR 72 TC 34 Z9 34 U1 0 U2 4 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 OCT PY 1999 VL 97 IS 4 BP 786 EP 801 PG 16 WC Fisheries SC Fisheries GA 256XX UT WOS:000083752700005 ER PT J AU Hunt, JJ Stobo, WT Almeida, F AF Hunt, JJ Stobo, WT Almeida, F TI Movement of Atlantic cod, Gadus morhua, tagged in the Gulf of Maine area SO FISHERY BULLETIN LA English DT Article AB Over 22,000 Atlantic cod, Gadus morhua, were tagged with T-bar tags and released in the Gulf of Maine area in 1984-97 and 2400 recovered tags were used to interpret movement of tagged fish. Most of the releases were of adult fish made during the winter cod spawning season from aggregations found on known spawning banks. Recaptures by NAFO divisions were weighted with an annual index of fishing effort to account for probability of recapture. At the division level, very little exchange between the area east of 4X and the Gulf of Maine was evident. However, within the Gulf of Maine an exchange of about 15% between 4X and 5Z and somewhat higher between 4X and 5Y was apparent. God tagged on Browns Bank and Georges Bank during the spawning season showed widespread dispersal both within their respective division and to adjacent divisions. The seasonal distribution of recaptures in 4X indicates aggregation for spawning followed by postspawning dispersal. The seasonal pattern for Georges Bank is less clear but there are indications of net loss to the 4X area. Distribution of recaptures from Georges Bank releases in 1994 was similar to those observed for releases made in 1984-85. Results of the study were consistent with results from earlier tagging experiments and demonstrate substantial interaction of cod from different management areas. These findings may have implications for stock assessment models and management objectives. C1 Fisheries & Oceans Canada, Biol Stn, St Andrews, NB E0G 2X0, Canada. Bedford Inst Oceanog, Dartmouth, NS B2Y 4A2, Canada. NOAA, Natl Marine Fisheries Serv, NE Fisheries Sci Ctr, Woods Hole, MA 02543 USA. RP Hunt, JJ (reprint author), Fisheries & Oceans Canada, Biol Stn, St Andrews, NB E0G 2X0, Canada. NR 22 TC 18 Z9 19 U1 1 U2 5 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 OCT PY 1999 VL 97 IS 4 BP 842 EP 860 PG 19 WC Fisheries SC Fisheries GA 256XX UT WOS:000083752700009 ER PT J AU Moser, HG Pommeranz, T AF Moser, HG Pommeranz, T TI Vertical distribution of eggs and larvae of northern anchovy, Engraulis mordax, and of the larvae of associated fishes at two sites in the Southern California bight SO FISHERY BULLETIN LA English DT Article ID SHALLOW COASTAL WATERS; SAN-ONOFRE; GENYONEMUS-LINEATUS; PELAGIC LARVAE; FISHES; ICHTHYOPLANKTON; ASSEMBLAGES; PLANKTON AB We studied fine-scale vertical distribution of northern anchovy, Engraulis mordax, eggs and larvae and larvae of associated species at two stations off southern California in March-April 1980 using a Manta (neuston) net and a MESSHAI (multiple opening-closing net) sampler. A pump and fluorometry system was used to obtain chloraphyll profiles. A storm with associated heavy seas interrupted sampling for two days at the inshore station and provided an opportunity to compare pre- and poststorm egg and larval distribution and abundance. A total of 95,552 fish larvae were taken in the MESSHAI (63 tows) and Manta nets (41 tows), representing 49 taxa (genera or species) in 27 families. Engraulis mordax was the most abundant fish (95% of the total), followed by Leuroglossus stilbius, Genyonemus lineatus, Stenobrachius leucopsarus, Sebastes spp., Seriphus politus, Peprilus simillimus, Paralichthys californicus, Citharichthys spp., and Merluccius productus. Anchovy eggs and larvae had a shallow distribution: 90% of larvae and 95% of eggs were found in the upper 30 m. Peak egg density was found in the neuston; peak larval density, in the 10-20 m stratum. Larvae of shallow-living shelf species (G. lineatus,P. simillimus, I! californicus) typically occurred in the upper 20-30 m, whereas larvae of predominantly deeper-living demersal species (Sebastes spp., M. productus) were found in the upper 80 m. Midwater species (L. stilbius, S. leucopsarus) occurred at least to 200 m. Anchovy eggs decreased in number after the storm. Anchovy larvae declined even more sharply, despite an increase in zooplankton and potential larval fish prey, suggesting that starvation may have resulted from disturbance of microscale food patches. Alternatively, larvae may have been advected away from the site. Shallow-water shelf species were rare at the inshore station before the storm but appeared suddenly afterwards as a result of seaward advection of shelf water by Ekman transport. C1 SW Fisheries Sci Ctr, La Jolla, CA 92038 USA. RP Moser, HG (reprint author), SW Fisheries Sci Ctr, POB 271, La Jolla, CA 92038 USA. NR 42 TC 30 Z9 31 U1 1 U2 10 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 OCT PY 1999 VL 97 IS 4 BP 920 EP 943 PG 24 WC Fisheries SC Fisheries GA 256XX UT WOS:000083752700015 ER PT J AU Natanson, LJ Casey, JG Kohler, NE Colket, T AF Natanson, LJ Casey, JG Kohler, NE Colket, T TI Growth of the tiger shark, Galeocerdo cuvier, in the western North Atlantic based on tag returns and length frequencies; and a note on the effects of tagging SO FISHERY BULLETIN LA English DT Article ID CARCHARHINUS-PLUMBEUS; NORTHWESTERN GULF; SANDBAR SHARK; RHIZOPRIONODON-TERRAENOVAE; SHARPNOSE SHARK; AGE ESTIMATION; MEXICO AB Growth parameter estimates were calculated for the tiger shark (Galeocerdo cuvier) by using tag and recapture data. Results were compared to published estimates based on bands in vertebrae. The von Bertalanffy parameters (sexes combined) based on Bag and recapture growth data were as follows: L-infinity = 337 cm fork length, k = 0.178, and t(0) = -1.12. Monthly length-frequency data for six year classes from birth to two years old for tiger sharks were used to verify the tag-recapture growth curve for this age range. The predicted age at maturity is 7 gears for both sexes. Data from an ongoing in situ study with oxytetracycline were used in conjunction with length data to determine the effect of tagging and oxytetracycline injection on growth. The data suggest that tagging alone or tagging combined with oxytetracycline injection has little or no effect on the growth rate of tiger sharks up to two years of age. C1 NOAA, Natl Marine Fisheries Serv, NE Fisheries Sci Ctr, Narragansett Lab, Narragansett, RI 02882 USA. RP Natanson, LJ (reprint author), NOAA, Natl Marine Fisheries Serv, NE Fisheries Sci Ctr, Narragansett Lab, Narragansett, RI 02882 USA. NR 36 TC 31 Z9 34 U1 1 U2 9 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 OCT PY 1999 VL 97 IS 4 BP 944 EP 953 PG 10 WC Fisheries SC Fisheries GA 256XX UT WOS:000083752700016 ER PT J AU Stoner, AW Bejda, AJ Manderson, JP Phelan, BA Stehlik, LL Pessutti, JP AF Stoner, AW Bejda, AJ Manderson, JP Phelan, BA Stehlik, LL Pessutti, JP TI Behavior of winter flounder, Pseudopleuronectes americanus, during the reproductive season: laboratory and field observations on spawning, feeding, and locomotion SO FISHERY BULLETIN LA English DT Article ID NEW-YORK BIGHT; PLEURONECTES-PLATESSA L; HIPPOGLOSSOIDES-PLATESSOIDES; NORTH-SEA; BAY; MATURATION; OCELLATUS; FISHES; DIETS; POND AB Continuous observations in a large research aquarium (121 kL) over a 14-week period were combined with field collection in the Navesink River estuary, New Jersey, to explore the behavior of winter flounder (Pseudo-pleuronectes americanus) during and after the spawning season. Ten males and ten females held in the aquarium spawned over a 60-day period, with an average of 40 spawns per female and 147 spawns per male. Males initiated all observed spawning events, which occurred throughout the night, but primarily between sunset and midnight. Spawning by one pair frequently elicited sudden convergence and spawning by secondary males (up to six individuals); consequently, strictly paired spawning was uncommon (22% of events). Males and females were almost entirely nocturnal during the reproductive season but became increasingly diurnal during the postspawning season. C1 NOAA, Natl Marine Fisheries Serv, NE Fisheries Sci Ctr, Highlands, NJ 07732 USA. RP Stoner, AW (reprint author), NOAA, Natl Marine Fisheries Serv, NE Fisheries Sci Ctr, 74 Magruder Rd, Highlands, NJ 07732 USA. NR 41 TC 48 Z9 49 U1 0 U2 5 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 OCT PY 1999 VL 97 IS 4 BP 999 EP 1016 PG 18 WC Fisheries SC Fisheries GA 256XX UT WOS:000083752700021 ER PT J AU Vecchione, M AF Vecchione, M TI Extraordinary abundance of squid paralarvae in the tropical eastern Pacific Ocean during El Nino of 1987 SO FISHERY BULLETIN LA English DT Article C1 Natl Museum Nat Hist, Natl Marine Fisheries Serv, Systemat Lab, Washington, DC 20560 USA. RP Vecchione, M (reprint author), Natl Museum Nat Hist, Natl Marine Fisheries Serv, Systemat Lab, Washington, DC 20560 USA. NR 16 TC 33 Z9 33 U1 0 U2 0 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 OCT PY 1999 VL 97 IS 4 BP 1025 EP 1030 PG 6 WC Fisheries SC Fisheries GA 256XX UT WOS:000083752700023 ER PT J AU Watson, W AF Watson, W TI Early life history stages of the whitetip flyingfish, Cheilopogon xenopterus (Gilbert, 1890) (Pisces : Exocoetidae) SO FISHERY BULLETIN LA English DT Article AB The whitetip flyingfish, Cheilopogon xenopterus, is an epipelagic resident of tropical and subtropical eastern Pacific waters. Its eggs are spherical, average 1.8 mm in diameter, and have an homogeneous yolk and no oil globule. About 53 filaments averaging 1 mm in length are evenly distributed on the chorion. The notochord flexes, fin-ray formation is nearly complete, and the characteristic larval pigmentation pattern is established prior to hatching at a larval length of about 2.8-3.3 mm. Larvae hatch with pigmented eyes, functional mouth, and little remaining yolk. Pectoral- and pelvic-fm rays initially are short but elongate rapidly to ca. 25-50% and 20-40% of body length, respectively. A pair of mandibular barbels form at about 4 mm and fuse mesially at about 8 mm. Scales begin to form along the lateral line at about 13-14 mm and cover the body by 26 mm. The characteristic pigment pattern, visible through the early juvenile stage, consists of the following: melanophores scattered over the mid- and hindbrain, continuing posteriorly as two rows (increasing to four or more rows) along the dorsal margin; a row of melanophores on the horizontal septum of the tail (after hatching); a patch on each side over the hypural area; and two rows along the anal-fm base. Internal pigment is present on the mid- and hindbrain, over the gut, and over the notochord. The pectoral and pelvic fins are sparsely pigmented at hatching and become increasingly pigmented with growth. A barred pigment pattern begins to develop on the body at about 8 mm and by the juvenile stage about six bars are present. C1 NOAA, Natl Marine Fisheries Serv, SW Fisheries Sci Ctr, La Jolla, CA 92038 USA. RP Watson, W (reprint author), NOAA, Natl Marine Fisheries Serv, SW Fisheries Sci Ctr, POB 271, La Jolla, CA 92038 USA. NR 52 TC 1 Z9 2 U1 0 U2 0 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 OCT PY 1999 VL 97 IS 4 BP 1031 EP 1042 PG 12 WC Fisheries SC Fisheries GA 256XX UT WOS:000083752700024 ER PT J AU Yang, MS AF Yang, MS TI The trophic role of Atka mackerel, Pleurogrammus monopterygius, in the Aleutian Islands area SO FISHERY BULLETIN LA English DT Article ID ALASKA; PUFFINS C1 Alaska Fisheries Sci Ctr, Seattle, WA 98115 USA. RP Yang, MS (reprint author), Alaska Fisheries Sci Ctr, 7600 Sand Point Way NE, Seattle, WA 98115 USA. NR 29 TC 11 Z9 13 U1 1 U2 2 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 OCT PY 1999 VL 97 IS 4 BP 1047 EP 1057 PG 11 WC Fisheries SC Fisheries GA 256XX UT WOS:000083752700026 ER PT J AU von Savigny, C Funk, O Platt, U Pfeilsticker, K AF von Savigny, C Funk, O Platt, U Pfeilsticker, K TI Radiative smoothing in zenith-scattered skylight transmitted through optically thick clouds to the ground SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID STRATOCUMULUS; MODEL AB A ground-based photometer was used to monitor the temporal variation of the zenith-scattered skylight radiance (at lambda = 752 nm) with a temporal resolution of 2 Hz. In detail, eight data sets for different optically thick (tau(c) greater than or equal to 1/(1-g) with tau(c) being the cloud's optical thickness and g the asymmetry factor for Mie scattering) cloud covers were analyzed with standard spectral methods. A general feature of all cloudy sky radiance power spectra is the presence of a remarkable scale break occurring at spatial scales that approximately correspond to the vertical cloud extension. This finding is consistent with theoretical estimates by Marshak et al. [1995] and Davis et al. [1997b] based on radiative smoothing by photon diffusion in vertically extended, optically thick and homogeneous clouds. C1 Univ Heidelberg, Inst Umweltphys, D-6900 Heidelberg, Germany. NOAA, Aeron Lab, Boulder, CO 80303 USA. RP von Savigny, C (reprint author), York Univ, Ctr Res Earth & Space Sci, Toronto, ON M3J 2R7, Canada. RI von Savigny, Christian/B-3910-2014 NR 16 TC 8 Z9 8 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 OCT 1 PY 1999 VL 26 IS 19 BP 2949 EP 2952 DI 10.1029/1999GL900619 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 242UU UT WOS:000082960700014 ER PT J AU McPhaden, MJ Yu, X AF McPhaden, MJ Yu, X TI Equatorial waves and the 1997-98 El Nino SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID WESTERN PACIFIC; OSCILLATION; MODEL; ENSO AB New measurements and model results highlight the role of equatorial oceanic wave processes in affecting the evolution of the 1997-98 El Nino in ways not fully anticipated by delayed oscillator theory, a leading paradigm for the El Nino/Southern Oscillation (ENSO) cycle. The onset of the El Nino was linked to eastward propagating equatorial Kelvin waves forced by intraseasonal atmospheric oscillations originating over the Indian Ocean. The demise of the El Nino was related to a complex interplay of wind-forced and western boundary-forced waves that preconditioned the ocean to sudden sea surface temperature cooling initially centered between 125 degrees W and 170 degrees W along the equator. These large-scale ocean wave processes, and the ocean-atmosphere interactions that they mediate, have significant implications for understanding variability associated with El Nino-related climate swings. C1 NOAA, Pacific Marine Environm Lab, Seattle, WA 98115 USA. Univ Calif Santa Barbara, Goleta, CA 93117 USA. RP McPhaden, MJ (reprint author), NOAA, Pacific Marine Environm Lab, 7600 Sand Point Way NE, Seattle, WA 98115 USA. RI McPhaden, Michael/D-9799-2016 NR 15 TC 142 Z9 151 U1 1 U2 12 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 OCT 1 PY 1999 VL 26 IS 19 BP 2961 EP 2964 DI 10.1029/1999GL004901 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 242UU UT WOS:000082960700017 ER PT J AU Desrosiers, MF Nagy, VY Romanyukha, AA AF Desrosiers, MF Nagy, VY Romanyukha, AA TI Comment on article by Haskell, Hayes, and Kenner SO HEALTH PHYSICS LA English DT Letter ID DOSIMETRY C1 Natl Inst Stand & Technol, Ionizing Radiat Div, Phys Lab, Gaithersburg, MD 20899 USA. NR 5 TC 3 Z9 3 U1 0 U2 0 PU LIPPINCOTT WILLIAMS & WILKINS PI PHILADELPHIA PA 530 WALNUT ST, PHILADELPHIA, PA 19106-3621 USA SN 0017-9078 EI 1538-5159 J9 HEALTH PHYS JI Health Phys. PD OCT PY 1999 VL 77 IS 4 BP 470 EP 471 PG 2 WC Environmental Sciences; Public, Environmental & Occupational Health; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging SC Environmental Sciences & Ecology; Public, Environmental & Occupational Health; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging GA 235DD UT WOS:000082524000015 PM 10492355 ER PT J AU Darabi, J Ohadi, MM Fanni, MA Dessiatoun, SV Kedzierski, MA AF Darabi, J Ohadi, MM Fanni, MA Dessiatoun, SV Kedzierski, MA TI Effect of heating boundary conditions on pool boiling experiments SO HVAC&R RESEARCH LA English DT Article ID TUBE GEOMETRIES; 5 REFRIGERANTS; NUCLEATE AB The two widely used experimental methods for pool boiling experiments are evaluated. Boiling heat transfer data employing either the water heating or the electric heating method obtained by various researchers are compared and discussed. The electric heating method is a constant heat pur process, while the water heating method represents a pseudo-exponential temperature profile for the heating water along the tube. It is concluded that the temperature profile along the tube is the major cause of the difference between results from the two methods. The parameters that shape the temperature profile and cause differences are discussed. C1 Univ Maryland, Dept Mech Engn, Enhanced Heat Transfer Lab, College Pk, MD 20742 USA. Azad Univ, Tehran, Iran. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Darabi, J (reprint author), Univ Maryland, Dept Mech Engn, Enhanced Heat Transfer Lab, College Pk, MD 20742 USA. NR 15 TC 4 Z9 4 U1 0 U2 0 PU AMER SOC HEATING REFRIGERATING AIR-CONDITIONING ENG, INC, PI ATLANTA PA 1791 TULLIE CIRCLE NE, ATLANTA, GA 30329 USA SN 1078-9669 J9 HVAC&R RES JI HVAC&R Res. PD OCT PY 1999 VL 5 IS 4 BP 283 EP 296 DI 10.1080/10789669.1999.10391239 PG 14 WC Thermodynamics; Construction & Building Technology; Engineering, Mechanical SC Thermodynamics; Construction & Building Technology; Engineering GA 250NT UT WOS:000083395000002 ER PT J AU Cortes, E AF Cortes, E TI Standardized diet compositions and trophic levels of sharks SO ICES JOURNAL OF MARINE SCIENCE LA English DT Article DE trophic levels; diet composition; sharks; elasmobranchs; feeding ecology ID MARINE MAMMALS; FOOD WEBS; MODELS AB Sharks are marine consumers believed to occupy top positions in marine food webs. But surprisingly, trophic level estimates for these predators are almost non-existent. With the hope of helping better define the ecological role of sharks in marine communities, this paper presents standardized diet compositions and trophic revels calculated for a suite of species. Dietary composition for each species was derived from published quantitative studies using a weighted average index that takes into account sample size in each study. The trophic level (TL) values of the 11 food types used to characterize the diet (obtained from published accounts) were then used to calculate fractional trophic levers for 149 species representing eight orders and 23 families. Sharks as a group are tertiary consumers (TL>4), and significant differences were found among the six orders compared, which were attributable to differences between orectolobiforms (TL<4) and all other orders, and between hexanchiforms and both carcharhiniforms and squatiniforms. Among four families of carcharhiniform sharks, carcharhinids (TL=4.1, n=39) had a significantly higher TL than triakids (TL=3.8, n=19) and scyliorhinids (TL=3.9, n=21), but not sphyrnids (TL=3.9, n=6). When compared to trophic levels for other top predators of marine communities obtained from the literature, mean TL for sharks was significantly higher than for seabirds (n=28), but not for marine mammals (n=97). Trophic level and body size were positively correlated (r(s)=0.33), with the fit increasing (r(s)=0.41) when the three predominantly zooplanktivorous sharks were omitted, and especially when considering only carcharhinid sharks (r(s)=0.55). (C) 1999 International Council for the Exploration of the Sea. C1 Natl Marine Fisheries Serv, SE Fisheries Sci Ctr, Panama City Lab, Panama City, FL 32408 USA. RP Cortes, E (reprint author), Natl Marine Fisheries Serv, SE Fisheries Sci Ctr, Panama City Lab, 3500 Delwood Beach Rd, Panama City, FL 32408 USA. NR 16 TC 376 Z9 399 U1 7 U2 87 PU ACADEMIC PRESS LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 1054-3139 J9 ICES J MAR SCI JI ICES J. Mar. Sci. PD OCT PY 1999 VL 56 IS 5 BP 707 EP 717 DI 10.1006/jmsc.1999.0489 PG 11 WC Fisheries; Marine & Freshwater Biology; Oceanography SC Fisheries; Marine & Freshwater Biology; Oceanography GA 256YN UT WOS:000083754200013 ER PT J AU Jaron, JA Marks, RB Rytting, DK AF Jaron, JA Marks, RB Rytting, DK TI Robust SOLT and alternative calibrations for four-sampler vector network analyzers SO IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES LA English DT Article DE alternative; calibration; lumped element; short-open-load-thru; vector network analyzer AB This paper assesses the accuracy of several proposed lumped-element calibration techniques for four-sampler vector network analyzers in the face of imperfectly defined standards. We find that these methods offer a wide range of accuracies, depending on the standards and how well they can be modeled. We introduce a new robust short-open-load-thru calibration that requires the same measurement and computational effort as traditional methods, but provides much better accuracy in transmission measurements and slightly better accuracy in reflection measurements. C1 Natl Inst Stand & Technol, Boulder, CO 80303 USA. Hewlett Packard Co, Santa Rosa, CA 95403 USA. RP Jaron, JA (reprint author), Natl Inst Stand & Technol, 325 Broadway, Boulder, CO 80303 USA. NR 7 TC 15 Z9 17 U1 0 U2 4 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9480 J9 IEEE T MICROW THEORY JI IEEE Trans. Microw. Theory Tech. PD OCT PY 1999 VL 47 IS 10 BP 2008 EP 2013 DI 10.1109/22.795076 PG 6 WC Engineering, Electrical & Electronic SC Engineering GA 244JA UT WOS:000083047000013 ER PT J AU Janezic, MD Baker-Jarvis, J AF Janezic, MD Baker-Jarvis, J TI Full-wave analysis of a split-cylinder resonator for nondestructive permittivity measurements SO IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES LA English DT Article DE dielectric losses; dielectric measurement; nondestructive testing; permittivity measurement; resonators AB This paper presents a full-wave analysis of the split-cylinder resonator. We outline a model where the fringing fields are rigorously accounted for and the resonance condition is derived. Using this model, a method for nondestructively measuring the complex permittivity of materials is examined, Measurements of the complex permittivity for low-loss dielectric materials using the split-cylinder resonator agree well with measurements made in a cylindrical cavity, An uncertainty analysis for the complex permittivity is also provided. C1 Natl Inst Stand & Technol, Boulder, CO 80303 USA. RP Janezic, MD (reprint author), Natl Inst Stand & Technol, 325 Broadway, Boulder, CO 80303 USA. NR 7 TC 67 Z9 68 U1 0 U2 7 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9480 J9 IEEE T MICROW THEORY JI IEEE Trans. Microw. Theory Tech. PD OCT PY 1999 VL 47 IS 10 BP 2014 EP 2020 DI 10.1109/22.795077 PG 7 WC Engineering, Electrical & Electronic SC Engineering GA 244JA UT WOS:000083047000014 ER PT J AU Huo, WM Kim, YK AF Huo, WM Kim, YK TI Electron collision cross-section data for plasma modeling SO IEEE TRANSACTIONS ON PLASMA SCIENCE LA English DT Review DE chemistry; collision processes; database reliability; electrons; impact ionization; plasma properties ID LOW-ENERGY ELECTRONS; IMPACT IONIZATION; VIBRATIONAL-EXCITATION; FREE-RADICALS; DISSOCIATIVE ATTACHMENT; ELASTIC-SCATTERING; NEUTRAL RADICALS; INTERMEDIATE LIFETIMES; METHANE SCATTERING; DECAY ENERGETICS AB An overview of the current status in electron collision cross section databases for plasma modeling is presented, Emphasis is on dissociation, ionization, and dissociative ionization, The effect of the operating conditions on the relative importance of different collision mechanisms is discussed. For high density plasmas with low gas pressure, a second collision with electrons becomes likely and metastable states may play a role in the dissociation and ionization processes, A number of outstanding theoretical and experimental issues in the cross-section data are discussed. For the total ionization cross section, a four-parameter fitting formula is found to represent the numerical data well and the parameters for some molecules used in plasma modeling are presented. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. EM huo@pegasus.arc.nasa.gov; yong-ki.kim@nist.gov NR 148 TC 26 Z9 26 U1 0 U2 12 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 0093-3813 EI 1939-9375 J9 IEEE T PLASMA SCI JI IEEE Trans. Plasma Sci. PD OCT PY 1999 VL 27 IS 5 BP 1225 EP 1240 DI 10.1109/27.799798 PG 16 WC Physics, Fluids & Plasmas SC Physics GA 251PA UT WOS:000083453000002 ER PT J AU Martys, NS AF Martys, NS TI Energy conserving discrete Boltzmann equation for nonideal systems SO INTERNATIONAL JOURNAL OF MODERN PHYSICS C LA English DT Article DE BBGKY; BGK; discrete Boltzmann methods; hydrodynamic fluctuations; Lennard-Jones fluid; nonideal systems; thermal lattice Boltzmann ID LATTICE-BOLTZMANN; IMMISCIBLE FLUIDS; HARD-SPHERES; LIQUID-GAS; MODEL; SIMULATION; HYDRODYNAMICS AB The BBGKY formalism is utilized to obtain a set of moment equations to be satisfied by the collision operator in an energy conserving discrete Boltzmann equation for the case of a nonlocal interaction potential. A modified BGK form of the collision operator consistent with these moment equations is described. In the regime of isothermal hows, a previous proposed nonideal gas model is recovered. Other approaches to constructing the collision operator are discussed. Numerical implementation of the modified BGK form, using a thermal lattice Boltzmann model, is illustrated as an example. The time dependence of the density autocorrelation function was studied for this model and found, at early times, to be strongly affected by the constraint of total energy conservation. The long time behavior of the density autocorrelation function was consistent with the theory of hydrodynamic fluctuations. C1 NIST, Gaithersburg, MD 20895 USA. RP Martys, NS (reprint author), NIST, Bldg 226,Room B350, Gaithersburg, MD 20895 USA. NR 34 TC 13 Z9 13 U1 1 U2 8 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA JOURNAL DEPT PO BOX 128 FARRER ROAD, SINGAPORE 912805, SINGAPORE SN 0129-1831 J9 INT J MOD PHYS C JI Int. J. Mod. Phys. C PD OCT PY 1999 VL 10 IS 7 BP 1367 EP 1382 DI 10.1142/S0129183199001121 PG 16 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA 268ZC UT WOS:000084449700017 ER PT J AU Zachariah, MR Carrier, MJ AF Zachariah, MR Carrier, MJ TI Molecular dynamics computation of gas-phase nanoparticle sintering: A comparison with phenomenological models SO JOURNAL OF AEROSOL SCIENCE LA English DT Article ID SURFACE-AREA; PARTICLES; AEROSOL; COALESCENCE; SIZE; CONDENSATION; COLLISIONS; SIMULATION; BEHAVIOR; TITANIA AB The mechanism and kinetics of the growth of silicon nanoparticles via particle-particle interactions has been investigated through the use of classical molecular dynamics (MD) trajectory calculations. Computations over a broad range of temperatures and particle sizes have shown that particle sintering is very dependent on size and temperature when solid-like, and considerably less sensitive when liquid-like. These atomistic computations have been used for the first time to validate previously postulated phenomenological mechanisms/models for both solid and liquid particle coalescence. The results have shown that solid-like particles sinter by a solid-state diffusion mechanism while liquid-like particles sinter by a viscous flow mechanism. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Natl Inst Stand & Technol, Chem Sci & Technol Lab, Gaithersburg, MD 20899 USA. RP Zachariah, MR (reprint author), Univ Minnesota, Minneapolis, MN 55455 USA. NR 40 TC 102 Z9 102 U1 1 U2 27 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0021-8502 J9 J AEROSOL SCI JI J. Aerosol. Sci. PD OCT PY 1999 VL 30 IS 9 BP 1139 EP 1151 DI 10.1016/S0021-8502(98)00782-4 PG 13 WC Engineering, Chemical; Engineering, Mechanical; Environmental Sciences; Meteorology & Atmospheric Sciences SC Engineering; Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA 229LF UT WOS:000082195500002 ER PT J AU O'Neal, CL Crouch, DJ Rollins, DE Fatah, A Cheever, ML AF O'Neal, CL Crouch, DJ Rollins, DE Fatah, A Cheever, ML TI Correlation of saliva codeine concentrations with plasma concentrations after oral codeine administration SO JOURNAL OF ANALYTICAL TOXICOLOGY LA English DT Article ID HUMAN HAIR; MASS-SPECTROMETRY; COCAINE; DISPOSITION; METABOLITES; DRUGS; HEROIN; SINGLE; PATCH; ABUSE C1 Univ Utah, Dept Pharmacol & Toxicol, Ctr Human Tocicol, Salt Lake City, UT 84112 USA. Natl Inst Stand & Technol, Off Law Enforcement Stand, Gaithersburg, MD 20899 USA. RP Crouch, DJ (reprint author), Univ Utah, Dept Pharmacol & Toxicol, Ctr Human Tocicol, 20 S 2030 East,Room 490, Salt Lake City, UT 84112 USA. FU NIDA NIH HHS [DA07820] NR 31 TC 36 Z9 37 U1 0 U2 9 PU PRESTON PUBLICATIONS INC PI NILES PA 7800 MERRIMAC AVE PO BOX 48312, NILES, IL 60648 USA SN 0146-4760 J9 J ANAL TOXICOL JI J. Anal. Toxicol. PD OCT PY 1999 VL 23 IS 6 BP 452 EP 459 PG 8 WC Chemistry, Analytical; Toxicology SC Chemistry; Toxicology GA 242TL UT WOS:000082957700010 PM 10517550 ER PT J AU Bordage, MC Segur, P Christophorou, LG Olthoff, JK AF Bordage, MC Segur, P Christophorou, LG Olthoff, JK TI Boltzmann analysis of electron swarm parameters in CF4 using independently assessed electron-collision cross sections SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID LOW-ENERGY ELECTRONS; E-CF4 SCATTERING; IMPACT; HALOMETHANES; CONSISTENT; DISCHARGE; CCL2F2; CCL3F; CH4 AB Using independently assessed electron-collision cross sections, electron swarm parameters were calculated via the solution of the Boltzmann equation under the hydrodynamic regime. The cross sections used for the calculations were from a previously published assessment of electron-CF4-collision cross sections that was recently updated. All of the cross sections used are based on published measurements (except those for direct vibrational excitation), and were not modified during the calculations to improve agreement between the calculated swarm parameters and the experimental values. Agreement between calculated and measured values of the swarm parameters was good for the drift velocity in pure CF4 and in mixtures with argon, for the transverse diffusion coefficient in pure CF4, for the longitudinal diffusion coefficient in pure CF4 and in mixtures with argon, and for the electron attachment coefficient in pure CF4. Agreement is poor for the ionization coefficient in CF4 at most electric field-to-gas density ratios. The mostly reasonable agreement between the measured and calculated electron swarm parameters using the independently assessed cross sections validates the cross sections and the model. The use of independently assessed cross sections removes the potential arbitrariness and lack of uniqueness that often characterize cross section sets derived from Boltzmann analyses. Conjectures as to possible reasons for the lack of agreement between the calculated and measured values of the ionization coefficient are discussed. (C) 1999 American Institute of Physics. [S0021-8979(99)08519-9]. C1 Univ Toulouse 3, Ctr Phys Plasmas & Leurs Applicat Toulouse, F-31062 Toulouse, France. Natl Inst Stand & Technol, Div Elect, Elect & Elect Engn Lab, Gaithersburg, MD 20899 USA. RP Bordage, MC (reprint author), Univ Toulouse 3, Ctr Phys Plasmas & Leurs Applicat Toulouse, 118 Route Narbonne, F-31062 Toulouse, France. EM olthoff@eeel.nist.gov NR 31 TC 26 Z9 26 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 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD OCT 1 PY 1999 VL 86 IS 7 BP 3558 EP 3566 DI 10.1063/1.371258 PG 9 WC Physics, Applied SC Physics GA 237JL UT WOS:000082652400012 ER PT J AU Kim, JH Feldman, A Novotny, D AF Kim, JH Feldman, A Novotny, D TI Application of the three omega thermal conductivity measurement method to a film on a substrate of finite thickness SO JOURNAL OF APPLIED PHYSICS LA English DT Article AB The three omega thermal conductivity measurement method is analyzed for the case of one or more thin films on a substrate of finite thickness. The analysis is used to obtain the thermal conductivities of SiO2 films on Si substrates and of a chemical vapor deposition (CVD) diamond plate. For the case of the SiO2 films on a Si, we find an apparent thickness dependence of the thermal conductivity of the SiO2 films. However, the data can also be explained by a thickness-independent thermal conductivity and an interfacial thermal resistance. For the case of the CVD diamond plate, the fit of the theory to the experimental data is significantly improved if we assume that an interface layer separates the heater from the diamond plate. (C) 1999 American Institute of Physics. [S0021-8979(99)01319-5]. C1 NIST, Gaithersburg, MD 20899 USA. RP Kim, JH (reprint author), NIST, Gaithersburg, MD 20899 USA. NR 11 TC 115 Z9 118 U1 6 U2 54 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD OCT 1 PY 1999 VL 86 IS 7 BP 3959 EP 3963 DI 10.1063/1.371314 PG 5 WC Physics, Applied SC Physics GA 237JL UT WOS:000082652400074 ER PT J AU Sachidananda, M Zrnic, DS AF Sachidananda, M Zrnic, DS TI Systematic phase codes for resolving range overlaid signals in a Doppler weather radar SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article AB This paper deals with the recovery of Doppler velocities in the presence of range overlaid echoes. Transmitted pulses are phase shifted to tag the echoes from scatterers, which are separated by the unambiguous range. A new systematic phase code and an algorithm for estimating the mean velocities of overlaid first- and second-trip signals are presented. The return samples are phase corrected to cohere the first- or the second-trip signal, leaving the other signal power spread in a deterministic manner across the Doppler spectrum. An algorithm has been developed to recover the velocity of the weaker signal even if the power ratio of overlaid signals is as large as 40 dB, for spectrum widths of 4 m s(-1) or less, and an unambiguous velocity of 32 m s(-1). Tests on simulated weather signals indicate that the method, employed in surveillance Doppler radars, can effectively double the unambiguous range without the sacrifice of the unambiguous velocity interval. C1 Natl Severe Storms Lab, Norman, OK 73069 USA. Univ Oklahoma, CIMMS, Norman, OK 73019 USA. RP Zrnic, DS (reprint author), Natl Severe Storms Lab, 1313 Halley Circle, Norman, OK 73069 USA. NR 10 TC 33 Z9 34 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0739-0572 J9 J ATMOS OCEAN TECH JI J. Atmos. Ocean. Technol. PD OCT PY 1999 VL 16 IS 10 BP 1351 EP 1363 DI 10.1175/1520-0426(1999)016<1351:SPCFRR>2.0.CO;2 PG 13 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA 242TV UT WOS:000082958500008 ER PT J AU Torres, SM Zrnic, DS AF Torres, SM Zrnic, DS TI Ground clutter canceling with a regression filter SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article ID DOPPLER SYSTEMS; SIGNALS AB This paper explores ground clutter filtering with a class of cancelers that use regression. Regression filters perform this task in a simple manner. resulting in similar or better performance than the fifth-order elliptic filter implemented in the WSR-88D. Assuming a slowly varying clutter signal, a suitable projection of the composite signal is used to notch a band of frequencies at either side of zero Doppler frequency. The complexity of this procedure is reduced by using a set of orthogonal polynomials. The frequency response of the resulting filter is related to the number of samples in each input block and the maximum order of approximating polynomials. Through simulations, it is demonstrated that the suppression characteristic of this filter is better than that of step-initialized infinite impulse response filters, whereby transients degrade the theoretical frequency response. The performance of regression filters is tested with an actual weather signal, and their efficiency in ground clutter canceling is demonstrated. C1 NOAA, Environm Res Lab, Natl Severe Storms Lab, Norman, OK 73069 USA. Cooperat Inst Mesoscale Meteorol Studies, Norman, OK USA. RP Torres, SM (reprint author), NOAA, Environm Res Lab, Natl Severe Storms Lab, 1313 Halley Circle, Norman, OK 73069 USA. NR 13 TC 19 Z9 19 U1 0 U2 0 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 OCT PY 1999 VL 16 IS 10 BP 1364 EP 1372 DI 10.1175/1520-0426(1999)016<1364:GCCWAR>2.0.CO;2 PG 9 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA 242TV UT WOS:000082958500009 ER PT J AU Vossepoel, FC Reynolds, RW Miller, L AF Vossepoel, FC Reynolds, RW Miller, L TI Use of sea level observations to estimate salinity variability in the tropical Pacific SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article ID WESTERN EQUATORIAL PACIFIC; ATMOSPHERE RESPONSE EXPERIMENT; DATA ASSIMILATION SYSTEM; MIXED-LAYER; BARRIER-LAYER; TOGA DECADE; WARM POOL; PART I; OCEAN; SURFACE AB The equatorial sea level analysis of the National Centers for Environmental Predictions deviates by as much as 8 cm from independent TOPEX/Poseidon (T/P) observations. This may be due to the model's underestimation of salinity variability. Therefore, methods are developed to improve the model's salinity field through T/P data assimilation and use of sea surface salinity (SSS) observations. In regions where temperature is well known, salinity estimates are made with the use of climatological temperature-salinity (T-S) correlations. These estimates are improved by combining T-S with SSS observations and corrected with dynamic height, which provides information on salinity variability. Tests with independent conductivity temperature depth data show that the combination of TS with SSS significantly improves salinity estimates. In the western Pacific, the maximum root-mean-square (rms) estimation error of 0.55 psu is reduced to 0.42 psu by the use of SSS in the salinity estimate. Correction with dynamic height reduces this rms to 0.22 psu. Also in other parts of the tropical Pacific Ocean the salinity estimation errors are reduced by a factor of 2 by combination of the T-S estimate with SSS and dynamic height. This study provides the first step toward an assimilation scheme in which salinity is corrected with the use of T/P sea level observations. C1 Delft Univ Technol, Fac Aerosp Engn, Delft Inst Earth Oriented Space Res, NL-2629 HS Delft, Netherlands. NOAA, Lab Satellite Altimetry, Silver Spring, MD USA. Natl Ctr Environm Predict, Camp Springs, MD USA. RP Vossepoel, FC (reprint author), Delft Univ Technol, Fac Aerosp Engn, Delft Inst Earth Oriented Space Res, Room 911,Kluyverweg 1, NL-2629 HS Delft, Netherlands. RI Miller, Laury/B-8305-2011 OI Miller, Laury/0000-0003-3095-5804 NR 44 TC 31 Z9 33 U1 0 U2 0 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 OCT PY 1999 VL 16 IS 10 BP 1401 EP 1415 DI 10.1175/1520-0426(1999)016<1401:UOSLOT>2.0.CO;2 PG 15 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA 242TV UT WOS:000082958500012 ER PT J AU McIntosh, A Wang, Z Castillo-Chara, J Lucchese, RR Bevan, JW Suenram, RD Legon, AC AF McIntosh, A Wang, Z Castillo-Chara, J Lucchese, RR Bevan, JW Suenram, RD Legon, AC TI The structure and ground state dynamics of Ar-IH SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID LEVEL-CORRELATED CALCULATIONS; MOLECULAR ELECTRIC PROPERTIES; POLARIZED BASIS-SETS; INFRARED-SPECTROSCOPY; ROTATIONAL SPECTRA; WATER DIMER; AB-INITIO; HCN-HF; ARNHF; ATOMS AB The structure and ground state dynamics of the atom-diatom dimer interaction between Ar and HI has been investigated by microwave and near infrared supersonic jet spectroscopy. Ab initio molecular orbital calculations were used to provide greater insight into the nature of the interaction. The ground state is shown to be in the isomeric form Ar-IH with R-cm=3.9975(1) A, theta=149.33(1)degrees for the normal isotopomer and R-cm=3.9483(1) Angstrom, theta=157.11(1)degrees for Ar-ID. The potential surface from an ab initio molecular orbital calculation was scaled and shifted to yield a nonlinear least-squares fit of the rovibrational state energies to the experimental data. The ground state potential energy surface obtained in this manner has a barrier between the Ar-IH and Ar-HI isomers of 88.5 cm(-1) with respect to the global minimum. Such calculations are also used to predict the presence of localized states in the secondary minimum associated with isomers Ar-HI and Ar-DI. Attempts to experimentally identify transitions associated with the latter were unsuccessful. The ground state, Ar-IH isomeric structure, contrasts with the corresponding ground state of the other members of the homologous series Ar-HX (X=F, Cl, and Br) in which the Ar is bound to the proton. (C) 1999 American Institute of Physics. [S0021-9606(99)00837-5]. C1 Texas A&M Univ, Dept Chem, College Stn, TX 77843 USA. Natl Inst Stand & Technol, Opt Technol Div, Gaithersburg, MD 20899 USA. Univ Exeter, Sch Chem, Exeter EX4 4QD, Devon, England. RP McIntosh, A (reprint author), Texas A&M Univ, Dept Chem, College Stn, TX 77843 USA. RI Bevan, John/B-6529-2015; Lucchese, Robert/O-4452-2014 OI Bevan, John/0000-0003-0264-6596; Lucchese, Robert/0000-0002-7200-3775 NR 34 TC 30 Z9 30 U1 0 U2 4 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD OCT 1 PY 1999 VL 111 IS 13 BP 5764 EP 5770 DI 10.1063/1.479873 PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 238UW UT WOS:000082732100014 ER PT J AU Lefebvre, AA Lee, JH Jeon, HS Balsara, NP Hammouda, B AF Lefebvre, AA Lee, JH Jeon, HS Balsara, NP Hammouda, B TI Initial stages of nucleation in phase separating polymer blends SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID ANGLE NEUTRON-SCATTERING; MULTICOMPONENT POLYOLEFIN BLENDS; PROTONATED POLYBUTADIENE BLENDS; SPINODAL DECOMPOSITION; THERMODYNAMIC INTERACTIONS; DENSITY-FLUCTUATIONS; LIGHT-SCATTERING; HYDROCARBON POLYMERS; MIXTURE; KINETICS AB The initial stages of nucleation during liquid-liquid phase separation in mixtures of high molecular weight polymers was studied by time-resolved small angle neutron scattering. Phase separation was induced either by decreasing temperature or by increasing pressure. One of the blend components was labeled with deuterium to obtain sufficient scattering contrast between the components. The general features of nucleation were independent of quench depth and the nature of the quench (temperature quench versus pressure quench). The early stages of nucleation consisted of amplification of concentration fluctuations. During this stage, the scattered intensity (I) in the low scattering vector (q) limit was consistent with the Ornstein-Zernike equation. This enabled the determination of the characteristic length scale of the growing fluctuations, xi. The I vs q behavior at intermediate scattering vectors (q > 1/xi) could be described by a power law (I similar to q(-d)). We demonstrate the existence of a time-temperature superposition principle during nucleation: The time dependence of d at different quench depths could be superimposed by a lateral shift of the data along the time axis (log scale). In analogy to the shift factor for viscoelastic behavior of polymers, we define a nucleation shift factor, a(N), which describes the slowing down of nucleation kinetics with decreasing quench depth. Similarly, nucleation after pressure quenches can be described by a time-pressure superposition law. For each quench, we find that the scattering intensity is independent of time in the high q regime (q > q(merge)). This implies the absence of growing structures with length scales smaller than xi(crit)=1/q(merge) during nucleation. This aspect of nucleation is consistent with classical theories which predict the existence of a critical nucleus size. As expected, xi(crit) increases with decreasing quench depth. (C) 1999 American Institute of Physics. [S0021-9606(99)50437-6]. C1 Polytech Univ, Dept Chem Engn Chem & Mat Sci, Brooklyn, NY 11201 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Balsara, NP (reprint author), Polytech Univ, Dept Chem Engn Chem & Mat Sci, 6 Metrotech Ctr, Brooklyn, NY 11201 USA. NR 58 TC 22 Z9 22 U1 2 U2 13 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD OCT 1 PY 1999 VL 111 IS 13 BP 6082 EP 6099 DI 10.1063/1.479906 PG 18 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 238UW UT WOS:000082732100049 ER PT J AU Robertson, B AF Robertson, B TI Comment on "Remarks on the information entropy maximization method and extended thermodynamics" SO JOURNAL OF CHEMICAL PHYSICS LA English DT Letter C1 NIST, Div Biotechnol, Gaithersburg, MD 20899 USA. RP Robertson, B (reprint author), NIST, Div Biotechnol, Gaithersburg, MD 20899 USA. NR 14 TC 1 Z9 1 U1 2 U2 2 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD OCT 1 PY 1999 VL 111 IS 13 BP 6144 EP 6145 DI 10.1063/1.479910 PG 2 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 238UW UT WOS:000082732100055 ER PT J AU Dolan, JW Snyder, LR Wolcott, RG Haber, P Baczek, T Kaliszan, R Sander, LC AF Dolan, JW Snyder, LR Wolcott, RG Haber, P Baczek, T Kaliszan, R Sander, LC TI Reversed-phase liquid chromatographic separation of complex samples by optimizing temperature and gradient time III. Improving the accuracy of computer simulation SO JOURNAL OF CHROMATOGRAPHY A LA English DT Article DE optimization; temperature effects; gradient elution; computer simulation; mobile phase composition; retention times ID HPLC METHOD DEVELOPMENT; SOLVENT-STRENGTH; RETENTION DATA; ELUTION; SELECTIVITY; OPTIMIZATION; PREDICTION; STEEPNESS; MODEL; PH AB Previous studies have shown that four experimental runs, where both temperature T and gradient time t(G) are varied, can be used for the reliable prediction of separation as a function of these two variables (two-dimensional optimization). Computer simulation (e.g., DryLab) can then be used to predict "optimized" conditions for maximum sample resolution using either isocratic or gradient elution. Samples that contain a large number of components (e.g., n>15-20) present a greater challenge. Resolution for these more complex samples is often quite sensitive to small changes in T or t(G), in turn requiring greater accuracy in predictions that result from computer simulation. In the present study of several samples, we have examined computer simulation errors that can arise from inexact expressions for retention time as a function of T, t(G) or isocratic %B. Resulting conclusions are applicable to both complex and simpler samples, in either one- or two-dimensional optimization. Means to anticipate and minimize the impact of these predictive errors are examined. (C) 1999 Elsevier Science B.V. All rights reserved. C1 LC Resources Inc, Walnut Creek, CA 94596 USA. Linfield Coll, Dept Chem, McMinnville, OR 97128 USA. Med Univ Gdansk, Dept Biopharmaceut & Pharmacodynam, PL-80416 Gdansk, Poland. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Snyder, LR (reprint author), LC Resources Inc, 2930 Camino Diablo,Suite 110, Walnut Creek, CA 94596 USA. RI Kaliszan, Roman/E-4784-2011 NR 31 TC 77 Z9 78 U1 1 U2 10 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0021-9673 J9 J CHROMATOGR A JI J. Chromatogr. A PD OCT 1 PY 1999 VL 857 IS 1-2 BP 41 EP 68 DI 10.1016/S0021-9673(99)00766-9 PG 28 WC Biochemical Research Methods; Chemistry, Analytical SC Biochemistry & Molecular Biology; Chemistry GA 243VM UT WOS:000083018200003 PM 10536825 ER PT J AU Locascio, LE Perso, CE Lee, CS AF Locascio, LE Perso, CE Lee, CS TI Measurement of electroosmotic flow in plastic imprinted microfluid devices and the effect of protein adsorption on flow rate SO JOURNAL OF CHROMATOGRAPHY A LA English DT Article DE electroosmotic flow; instrumentation; imprinted polymers; polymer microfluid devices; proteins ID ORGANIC POLYMER CAPILLARIES; DNA ANALYSIS DEVICE; PCR AMPLIFICATION; ELECTROPHORESIS; FABRICATION AB Several commercially available plastic materials were used as substrates in Phe fabrication of microfluid channels for biochemical analysis. Protocols for fabrication using the wire-imprinting method are reported for polystyrene, polymethylmethacrylate and a copolyester material. Channel sealing was accomplished by low-temperature bonding of a substrate of similar material; therefore, each channel was composed of a single material on all sides. The electroosmotic flow in 25-mu m imprinted channels was evaluated for each substrate material. The copolyester material exhibited the highest electroosmotic flow mobility of 4.3 . 10(-4) cm(2) V-1 s(-1) which is similar to that previously reported for fused-silica capillaries. Polystyrene exhibited the lowest electroosmotic flow mobility of 1.8 . 10(-4) cm(2) V-1 s(-1). Plots of linear velocity versus applied electric field strength were linear from 100 V cm(-1) to 500 V cm(-1) indicating that heat dissipation is effective for all substrates in this range. Electroosmotic flow was reevaluated in the plastic channels following incubation in antibody solution to access the non-specific binding characteristics of a common biochemical reagent onto the substrate materials. All materials tested showed a high degree of non-specific adsorption of IgG as indicated by a decrease in the electroosmotic flow mobility in post-incubation testing. Published by Elsevier Science B.V. C1 Natl Inst Stand & Technol, Div Analyt Chem, Gaithersburg, MD 20899 USA. Univ Maryland, Dept Chem & Biochem, College Pk, MD 20742 USA. RP Locascio, LE (reprint author), Natl Inst Stand & Technol, Div Analyt Chem, Gaithersburg, MD 20899 USA. NR 21 TC 150 Z9 152 U1 7 U2 36 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0021-9673 J9 J CHROMATOGR A JI J. Chromatogr. A PD OCT 1 PY 1999 VL 857 IS 1-2 BP 275 EP 284 DI 10.1016/S0021-9673(99)00774-8 PG 10 WC Biochemical Research Methods; Chemistry, Analytical SC Biochemistry & Molecular Biology; Chemistry GA 243VM UT WOS:000083018200024 PM 10536846 ER PT J AU Phinney, KW Jinadu, LA Sander, LC AF Phinney, KW Jinadu, LA Sander, LC TI Chiral selectors from fruit: application of citrus pectins to enantiomer separations in capillary electrophoresis SO JOURNAL OF CHROMATOGRAPHY A LA English DT Article DE enantiomer separation; chiral selectors; pectins ID ZONE ELECTROPHORESIS; POLYSACCHARIDES; COMPONENTS; PROTEINS; HEPARIN; GELS AB Pectins were investigated as chiral selective agents in capillary electrophoresis. Successful enantioresolution of antihistaminic and antimalarial compounds, as well as others, was achieved by utilizing potassium polypectate as the chiral selector. Changes in pH, chiral additive concentration and capillary type were studied in relation to chiral resolution. The effect of degree of esterification of pectin materials on chiral recognition was also evaluated. Published by Elsevier Science B.V. C1 NIST, Chem Sci & Technol Lab, Div Analyt Chem, Gaithersburg, MD 20899 USA. RP Phinney, KW (reprint author), NIST, Chem Sci & Technol Lab, Div Analyt Chem, Gaithersburg, MD 20899 USA. NR 20 TC 24 Z9 25 U1 3 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0021-9673 J9 J CHROMATOGR A JI J. Chromatogr. A PD OCT 1 PY 1999 VL 857 IS 1-2 BP 285 EP 293 DI 10.1016/S0021-9673(99)00777-3 PG 9 WC Biochemical Research Methods; Chemistry, Analytical SC Biochemistry & Molecular Biology; Chemistry GA 243VM UT WOS:000083018200025 PM 10536847 ER PT J AU Matthews, AJ Kiladis, GN AF Matthews, AJ Kiladis, GN TI Interactions between ENSO, transient circulation, and tropical convection over the Pacific SO JOURNAL OF CLIMATE LA English DT Article ID EL-NINO; BAROCLINIC ATMOSPHERE; WAVE-PROPAGATION; NORTHERN WINTER; ROSSBY WAVES; MEAN-FLOW; OSCILLATION; FREQUENCY; PATTERNS; MODEL AB The interannual variability of transient waves and convection over the central and eastern Pacific is examined using 30 northern winters of NCEP-NCAR reanalyses (1968/69-1997/98) and satellite outgoing longwave radiation data starting in 1974. There is a clear signal associated with the El Nino-Southern Oscillation, such that differences in the seasonal-mean basic stale lead to statistically significant changes in the behavior of the transients and convection (with periods less than 30 days), which then feed back onto the basic state. During a warm event (El Nino phase), the Northern Hemisphere subtropical jet is strengthened over the central Pacific; the region of upper-tropospheric mean easterlies over the tropical western Pacific expands eastward past the date line, and the upper-tropospheric mean "westerly duct" over the tropical eastern Pacific is weakened. The transients tend to propagate along the almost continuous waveguide of the subtropical jet; equatorward propagation into the westerly duct is reduced. The transient convective events over the ITCZ typically observed to be associated with these equatorward-propagating waves are subsequently reduced both in number and magnitude, leading to a seasonal-mean net negative diabatic heating anomaly over the central Pacific from 10 degrees to 20 degrees N, which then feeds back onto the basic stare. During a cold event (La Nina phase), the situation is reversed. The different propagation characteristics of the transients in El Nino and La Nina basic states are well simulated in initial value experiments with a primitive equation model. C1 Univ Colorado, Cooperat Inst Res Environm Sci, NOAA, Boulder, CO 80309 USA. NOAA, Aeron Lab, Boulder, CO 80303 USA. RP Matthews, AJ (reprint author), Univ E Anglia, Sch Environm Sci, Norwich NR4 7TJ, Norfolk, England. RI Matthews, Adrian/A-6444-2011 OI Matthews, Adrian/0000-0003-0492-1168 NR 36 TC 59 Z9 61 U1 0 U2 4 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 OCT PY 1999 VL 12 IS 10 BP 3062 EP 3086 DI 10.1175/1520-0442(1999)012<3062:IBETCA>2.0.CO;2 PG 25 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 246KQ UT WOS:000083163300008 ER PT J AU Schneider, T Griffies, SM AF Schneider, T Griffies, SM TI A conceptual framework for predictability studies SO JOURNAL OF CLIMATE LA English DT Article ID MULTIDECADAL CLIMATE VARIABILITY; MULTIPLE TIME-SERIES; SST ANOMALIES DRIVEN; DISCRIMINANT-ANALYSIS; MODEL; CIRCULATION; SIMULATIONS; FORECASTS; ENSEMBLE; ENTROPY AB A conceptual framework is presented for a unified treatment of issues arising in a variety of predictability studies. The predictive power (PP), a predictability measure based on information-theoretical principles, lies at the center of this framework. The PP is invariant under linear coordinate transformations and applies to multivariate predictions irrespective of assumptions about the probability distribution of prediction errors. For univariate Gaussian predictions, the PP reduces to conventional predictability measures that are based upon the ratio of the rms error of a model prediction over the rms error of the climatological mean prediction. Since climatic variability on intraseasonal to interdecadal timescales follows an approximately Gaussian distribution, the emphasis of this paper is on multivariate Gaussian random variables. Predictable and unpredictable components of multivariate Gaussian systems can be distinguished by predictable component analysis, a procedure derived from discriminant analysis: seeking components with large PP leads to an eigenvalue problem, whose solution yields uncorrelated components that are ordered by PP from largest to smallest. In a discussion of the application of the PP and the predictable component analysis in different types of predictability studies, studies are considered that use either ensemble integrations of numerical models or autoregressive models fitted to observed or simulated data. An investigation of simulated multidecadal variability of the North Atlantic illustrates the proposed methodology. Reanalyzing an ensemble of integrations of the Geophysical Fluid Dynamics Laboratory coupled general circulation model confirms and refines earlier findings. With an autoregressive model fitted to a single integration of the same model, it is demonstrated that similar conclusions can be reached without resorting to computationally costly ensemble integrations. C1 Princeton Univ, AOS Program, Princeton, NJ 08544 USA. NOAA, Geophys Fluid Dynam Lab, Princeton, NJ USA. RP Schneider, T (reprint author), Princeton Univ, AOS Program, Princeton, NJ 08544 USA. RI Schneider, Tapio /A-7038-2014 OI Schneider, Tapio /0000-0001-5687-2287 NR 65 TC 105 Z9 108 U1 1 U2 12 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 OCT PY 1999 VL 12 IS 10 BP 3133 EP 3155 DI 10.1175/1520-0442(1999)012<3133:ACFFPS>2.0.CO;2 PG 23 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 246KQ UT WOS:000083163300012 ER PT J AU Jablonski, A Powell, CJ AF Jablonski, A Powell, CJ TI Relationships between electron inelastic mean free paths, effective attenuation lengths, and mean escape depths SO JOURNAL OF ELECTRON SPECTROSCOPY AND RELATED PHENOMENA LA English DT Article ID RAY-PHOTOELECTRON-SPECTROSCOPY; ELASTIC-SCATTERING CORRECTIONS; ANGLE-RESOLVED XPS; ANGULAR-DISTRIBUTION; RELATIVE INTENSITIES; AUGER ELECTRONS; POLYCRYSTALLINE SOLIDS; NONCRYSTALLINE SOLIDS; CORRECTION FORMULA; QUANTITATIVE AES AB The terms inelastic mean free path (IMFP), effective attenuation length (EAL), and mean escape depth (MED) are frequently used to specify the surface sensitivity of Auger-electron spectroscopy (AES) and X-ray photoelectron spectroscopy (XPS). These terms are different conceptually because of the effects of elastic-electron scattering, and generally have different numerical values for a specified material and electron energy. In addition, values of the EAL and MED depend on the instrumental configuration. We give an historical overview of efforts to measure EALs by the overlayer method and of work to investigate elastic-scattering effects in AES and XPS. We then apply an analytical formalism developed from a solution of the kinetic Boltzmann equation within the transport approximation to demonstrate the relationships between the IMFP, EAL, and MED for selected elemental solids and for common measurement conditions. Examples are given to show the magnitude of elastic-scattering effects on MED values for angle-resolved XPS and AES. If XPS or AES data are acquired for emission angles between zero and 60 degrees, the ratio of the MED to that found with elastic scattering neglected is approximately constant (to within 10%), and this ratio can be used to determine an average value for the EAL. This EAL value can then be used to establish the depth scale in the data analysis. Finally, we show ratios of the EAL to the: IMFP for XPS from the Au 4s subshell with Mg K alpha X-rays as a function of emission angle and depth; this ratio has a weak dependence on emission angle from zero to 40 degrees but a more pronounced dependence for larger emission angles. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Natl Inst Stand & Technol, Surface & Microanal Sci Div, Gaithersburg, MD 20899 USA. Polish Acad Sci, Inst Phys Chem, PL-01224 Warsaw, Poland. RP Powell, CJ (reprint author), Natl Inst Stand & Technol, Surface & Microanal Sci Div, Gaithersburg, MD 20899 USA. NR 69 TC 94 Z9 95 U1 6 U2 31 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0368-2048 J9 J ELECTRON SPECTROSC JI J. Electron Spectrosc. Relat. Phenom. PD OCT PY 1999 VL 100 SI SI BP 137 EP 160 DI 10.1016/S0368-2048(99)00044-4 PG 24 WC Spectroscopy SC Spectroscopy GA 251JM UT WOS:000083442300009 ER PT J AU Carlson, JK Parsons, GR AF Carlson, JK Parsons, GR TI Seasonal differences in routine oxygen consumption rates of the bonnethead shark SO JOURNAL OF FISH BIOLOGY LA English DT Article DE shark; oxygen consumption; temperature; Q(10) ID SPHYRNA-TIBURO AB Routine oxygen consumption rates of bonnethead sharks, Sphyrna tiburo, increased from 141.3 +/- 29.7 mg O-2 kg(-1) h(-1) during autumn to 218.6 +/- 64.2 mg O-2 kg(-1) h(-1) during spring, and 329.7 +/- 38.3 mg O-2 kg(-1) h(-1) during summer. The rate of routine oxygen consumption increased over the entire seasonal temperature range (20-30 degrees C) at a Q(10)=2.34. (C) 1999 The Fisheries Society of the British Isles. C1 Univ Mississippi, Dept Biol, University, MS 38677 USA. RP Carlson, JK (reprint author), Natl Marine Fisheries Serv, SE Fisheries Sci Ctr, 3500 Delwood Beach Rd, Panama City, FL 32408 USA. NR 10 TC 27 Z9 29 U1 0 U2 6 PU ACADEMIC PRESS LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 0022-1112 J9 J FISH BIOL JI J. Fish Biol. PD OCT PY 1999 VL 55 IS 4 BP 876 EP 879 DI 10.1111/j.1095-8649.1999.tb00724.x PG 4 WC Fisheries; Marine & Freshwater Biology SC Fisheries; Marine & Freshwater Biology GA 244FF UT WOS:000083040600015 ER PT J AU Dryer, M Wu, CC Smith, ZK AF Dryer, M Wu, CC Smith, ZK TI Comment on "The solar energetic particle event of April 14, 1994, as a probe of shock formation and particle acceleration" by S. W. Kahler, H. V. Cane, H. S. Hudson, V. G. Kurt, Y. V. Gotselyuk, R. J. MacDowall, and V. Bothmer SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Editorial Material ID HELIOSPHERIC PLASMA SHEET; CORONAL MASS EJECTIONS; INTERPLANETARY; PROPAGATION; SIMULATION C1 NOAA, Space Environm Ctr, Boulder, CO 80303 USA. Univ Delaware, Bartol Res Inst, Newark, DE 19716 USA. RP Dryer, M (reprint author), NOAA, Space Environm Ctr, 325 Broadway, R-E-SE, Boulder, CO 80303 USA. RI xue, yansheng/A-9712-2012 NR 13 TC 1 Z9 1 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 OCT 1 PY 1999 VL 104 IS A10 BP 22407 EP 22409 DI 10.1029/1999JA900236 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 240YV UT WOS:000082855100009 ER PT J AU Coffey, HE AF Coffey, HE TI Geomagnetic and solar data SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article C1 NOAA, World Data Ctr A Solar Terr Phys, Boulder, CO 80303 USA. RP Coffey, HE (reprint author), NOAA, World Data Ctr A Solar Terr Phys, 325 Broadway, Boulder, CO 80303 USA. NR 0 TC 2 Z9 2 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 OCT 1 PY 1999 VL 104 IS A10 BP 22819 EP 22820 DI 10.1029/1999JA900262 PG 2 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 240YV UT WOS:000082855100044 ER PT J AU Coffey, HE AF Coffey, HE TI Geomagnetic and solar data SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article C1 NOAA, World Data Ctr A Solar Terr Phys, Boulder, CO 80303 USA. RP Coffey, HE (reprint author), NOAA, World Data Ctr A Solar Terr Phys, 325 Broadway, Boulder, CO 80303 USA. NR 0 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 OCT 1 PY 1999 VL 104 IS A10 BP 22821 EP 22821 DI 10.1029/1999JA900322 PG 1 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 240YV UT WOS:000082855100045 ER PT J AU Seo, DJ Breidenbach, JP Johnson, ER AF Seo, DJ Breidenbach, JP Johnson, ER TI Real-time estimation of mean field bias in radar rainfall data SO JOURNAL OF HYDROLOGY LA English DT Article DE radar; rainfall; bias; estimation ID VERTICAL PROFILES; RAINDROP SPECTRA; INVERSE METHOD; REFLECTIVITY; IDENTIFICATION AB To reduce systematic errors in radar rainfall data used for operational hydrologic forecasting, the precipitation estimation stream in the National Weather Service (NWS) uses procedures that estimate mean field bias in real time. Being a multiplicative correction over a very large area, bias adjustment has a huge impact, particularly on volumetric estimation of rainwater, and hence performance of the procedure is extremely important to quantitative hydrologic forecasting using radar rainfall data. In this paper, we describe a new procedure far real-time estimation of mean field bias in WSR-88D (Weather Surveillance Radar-1988 Doppler version) rainfall products. Based largely on operational experience of the existing procedures in NWS, the proposed procedure is intended to be unbiased, parsimonious, and intuitive. To evaluate the procedure, true validation is performed using hourly rain gage and WSR-88D rainfall data from Tulsa and Twin Lakes, Oklahoma. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Natl Weather Serv, Hydrol Res Lab, Off Hydrol, Silver Spring, MD 20910 USA. Natl Weather Serv, Hydrol Operat Div, Off Hydrol, Silver Spring, MD 20910 USA. RP Seo, DJ (reprint author), Natl Weather Serv, Hydrol Res Lab, Off Hydrol, 1325 East West Highway, Silver Spring, MD 20910 USA. NR 22 TC 141 Z9 144 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-1694 J9 J HYDROL JI J. Hydrol. PD OCT 1 PY 1999 VL 223 IS 3-4 BP 131 EP 147 DI 10.1016/S0022-1694(99)00106-7 PG 17 WC Engineering, Civil; Geosciences, Multidisciplinary; Water Resources SC Engineering; Geology; Water Resources GA 243BJ UT WOS:000082977000002 ER PT J AU Pierce, DT Unguris, J Celotta, RJ Stiles, MD AF Pierce, DT Unguris, J Celotta, RJ Stiles, MD TI Effect of roughness, frustration, and antiferromagnetic order on magnetic coupling of Fe/Cr multilayers SO JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS LA English DT Article DE magnetic multilayers; interlayer exchange coupling; interfacial disorder; spin density wave ID SPIN-DENSITY-WAVE; CR THIN-FILMS; INTERLAYER EXCHANGE; PHASE-DIAGRAM; FE FILMS; GIANT MAGNETORESISTANCE; EPITAXIAL FE/CR(211); OSCILLATION PERIODS; LAYERED STRUCTURES; NEEL TRANSITION AB The interplay between interfacial disorder and the antiferromagnetic order in Cr lends to complex behavior in Fe/Cr multilayers. Measurements of interlayer coupling are discussed for samples with different amounts of disorder ranging from optimally fabricated trilayers of Fe/Tr/Fe on Fe(0 0 1) whiskers, to trilayers with increasing degrees of interfacial roughness, and finally to superlattices of Fe/Cr. The coupling of ferromagnets through noble-metal spacer layers can be described by a model that consists of bilinear coupling averaged over thickness fluctuations and extrinsic biquadratic coupling induced by the thickness fluctuations. This, the conventional model, also describes much of the behavior observed for Fe/Cr multilayers. However, in this case, the antiferromagnetism in Cr lends to results not explained by the conventional model. For nearly ideal interfaces, the Fe-Cr coupling can induce order in Cr, modifying the temperature dependence of the interlayer coupling. In addition, interfacial disorder can frustrate the antiferromagnetic order in the Cr, leading to a variety of ordered states which have been observed by neutron scattering. Each of these ordered states, in turn modifies the interlayer coupling in unexpected ways. The different ways in which the systems minimize the frustration can explain the experimental results. (C) 1999 Elsevier Science B.V. All rights reserved. C1 NIST, Electron Phys Grp, Gaithersburg, MD 20899 USA. RP Pierce, DT (reprint author), NIST, Electron Phys Grp, Gaithersburg, MD 20899 USA. RI Stiles, Mark/K-2426-2012; Unguris, John/J-3989-2014 OI Stiles, Mark/0000-0001-8238-4156; NR 90 TC 141 Z9 146 U1 0 U2 19 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0304-8853 J9 J MAGN MAGN MATER JI J. Magn. Magn. Mater. PD OCT PY 1999 VL 200 IS 1-3 BP 290 EP 321 DI 10.1016/S0304-8853(99)00319-4 PG 32 WC Materials Science, Multidisciplinary; Physics, Condensed Matter SC Materials Science; Physics GA 241DP UT WOS:000082867700019 ER PT J AU Stiles, MD AF Stiles, MD TI Interlayer exchange coupling SO JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS LA English DT Review DE interlayer exchange coupling; spacer-layer thickness; Fermi surfaces; RKKY interaction ID QUANTUM-WELL STATES; LAYERED MAGNETIC-STRUCTURES; MOLECULAR-BEAM EPITAXY; AB-INITIO CALCULATIONS; GIANT MAGNETORESISTANCE; FERROMAGNETIC-LAYERS; FE/CR MULTILAYERS; TEMPERATURE-DEPENDENCE; OSCILLATION PERIODS; CO/RU MULTILAYERS AB The extensive research done on interlayer exchange coupling in transition metal multilayers has resulted in a deep understanding of this coupling and a remarkable agreement between theoretical results and measurements. The coupling between two magnetic layers separated by a non-magnetic spacer layer is mediated by the electrons of the spacer layer. The coupling, which oscillates in sign as a function of the thickness of the spacer layer, is closely related to the well-known RKKY interaction between magnetic impurities. Due to the existence of many high-quality measurements, it has been much more fully developed theoretically than the interaction between impurities. Theory predicts that the periods of the oscillatory coupling should depend on critical spanning vectors of the Fermi surface belonging to the spacer-layer material There is remarkable agreement far the measured periods and those predicted from the Fermi surfaces. There is also substantial agreement between theory and experiment on the strength of the coupling. This review presents the comparison between theory and experiment in some detail. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Natl Inst Stand & Technol, Electron Phys Grp, Gaithersburg, MD 20899 USA. RP Stiles, MD (reprint author), Natl Inst Stand & Technol, Electron Phys Grp, Bldg 220 Rm B206, Gaithersburg, MD 20899 USA. RI Stiles, Mark/K-2426-2012 OI Stiles, Mark/0000-0001-8238-4156 NR 133 TC 152 Z9 153 U1 2 U2 72 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0304-8853 J9 J MAGN MAGN MATER JI J. Magn. Magn. Mater. PD OCT PY 1999 VL 200 IS 1-3 BP 322 EP 337 DI 10.1016/S0304-8853(99)00334-0 PG 16 WC Materials Science, Multidisciplinary; Physics, Condensed Matter SC Materials Science; Physics GA 241DP UT WOS:000082867700020 ER PT J AU Kawashima, Y Suenram, RD Fraser, GT Lovas, FJ Hirota, E AF Kawashima, Y Suenram, RD Fraser, GT Lovas, FJ Hirota, E TI The rotational spectrum of Ar-SiH4 and Ar-SiD4 SO JOURNAL OF MOLECULAR SPECTROSCOPY LA English DT Article ID DER-WAALS COMPLEXES; POTENTIAL-ENERGY SURFACE; SPHERICAL TOP COMPLEXES; VIBRATIONAL DEPENDENCE; MICROWAVE-SPECTRUM; INFRARED-SPECTRUM; NU(3) BAND; SPECTROSCOPY; SPECTROMETER; TRANSITIONS AB Microwave spectra of Ar-(SiH4)-Si-28, Ar-(SiH4)-Si-29, Ar-(SiH4)-Si-28, and Ar-(SiD4)-Si-28 were recorded using a pulsed molecular beam Fourier transform microwave spectrometer. The K = 0 and K = 1 components of the J = 3 <-- 2 through the J = 7 <-- 6 transitions were measured and assigned in the 9-24 GHz region, For the primary Si-28 isotopic species, Ar-(SiH4)-Si-28 and Ar-(SiD4)-Si-28, a K = 0, A symmetry, a K = 0, F symmetry. a doubly degenerate K = 1, E symmetry; and an l/K-doubled, K = 1, F symmetry rotational progression are observed at the approximate to 1 K rotational temperature of the supersonic expansion. The rotational constants for the K = 0, A state for Ar-(SiH4)-Si-28 and Ar-(SiD4)-Si-28 are B = 1700.40624(9) MHz and 1630.687073(22) MHz and the centrifugal distortion constants are D-j = 29.089(3) and 20.0198(8) kHz and H-j = -1.91(3) and -0.851(8) Hz, respectively, where type A expanded uncertainties with a coverage factor, k = 3, are given here and elsewhere. The values of the rotational constants for the K = 0. A, and F states and for the K = 1, E state are in good agreement with the infrared-determined values for Ar-(SiH4)-Si-28. The measured linear Stark effect of the E-state transitions was analyzed to give a dipole moment of 9.24(8) x 10(-32) C.m [0.0277(2) D]. (C) 1999 Academic Press. C1 Kanagawa Inst Technol, Dept Appl Chem, Atsugi, Kanagawa 2430292, Japan. Natl Inst Stand & Technol, Opt Technol Div, Gaithersburg, MD 20899 USA. Grad Univ Adv Studies, Kanagawa 2400193, Japan. RP Kawashima, Y (reprint author), Kanagawa Inst Technol, Dept Appl Chem, 1030 Shimo Ogino, Atsugi, Kanagawa 2430292, Japan. NR 17 TC 4 Z9 4 U1 0 U2 3 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0022-2852 J9 J MOL SPECTROSC JI J. Mol. Spectrosc. PD OCT PY 1999 VL 197 IS 2 BP 232 EP 239 DI 10.1006/jmsp.1999.7926 PG 8 WC Physics, Atomic, Molecular & Chemical; Spectroscopy SC Physics; Spectroscopy GA 238ZD UT WOS:000082743900010 ER PT J AU Taichenachev, AV Tumaikin, AM Yudin, VI AF Taichenachev, AV Tumaikin, AM Yudin, VI TI One- and two-dimensional Bose-Einstein condensation of atoms in dark magneto-optical lattices SO JOURNAL OF OPTICS B-QUANTUM AND SEMICLASSICAL OPTICS LA English DT Article DE laser cooling; atomic lattices; Bose condensation ID TRAPPING ATOMS; GAS; POPULATION; STATES; TRAPS AB The motion of atoms in a dark magneto-optical lattice is considered. This lattice is formed by a non-uniformly polarized laser field in the presence of a static magnetic field. Cold atoms are localized in the vicinity of points where dark states are not destroyed by a magnetic field. As a result, the optical interaction tends to zero (dark or grey lattices). Depending on the field configuration such a lattice can exhibit one-dimensional (1D) or two-dimensional (2D) periodicity. It is shown that in ID and 2D dark magneto-optical lattices the effects connected with the Bose statistics of particles can be observed under temperatures 10(-5)-10(-6) K and densities 10(11)-10(12) cm(-3), i.e. those that are usual for current experiments on laser cooling. C1 Novosibirsk State Univ, Phys Lasers Lab, Novosibirsk 630090, Russia. Natl Inst Stand & Technol, Div Time & Frequency, Boulder, CO 80303 USA. RP Taichenachev, AV (reprint author), Novosibirsk State Univ, Phys Lasers Lab, Pirogova 2, Novosibirsk 630090, Russia. RI Taichenachev, Aleksei/K-7065-2015 OI Taichenachev, Aleksei/0000-0003-2273-0066 NR 24 TC 6 Z9 6 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 1464-4266 J9 J OPT B-QUANTUM S O JI J. Opt. B-Quantum Semicl. Opt. PD OCT PY 1999 VL 1 IS 5 BP 557 EP 561 DI 10.1088/1464-4266/1/5/311 PG 5 WC Optics; Physics, Applied SC Optics; Physics GA 251GX UT WOS:000083438100013 ER PT J AU Campbell, CE Kattner, UR AF Campbell, CE Kattner, UR TI A thermodynamic assessment of the Ni-Al-B system SO JOURNAL OF PHASE EQUILIBRIA LA English DT Article ID PHASE-DIAGRAM; ALUMINUM; BORON; ALLOYS; MODEL; DIFFUSION AB The thermodynamics of the Ni-Al-B system are assessed based on available literature data. Both the Ni-B and Al-B systems were revised to treat B as an interstitial element in a face-centered cubic structure, rather than as a substitutional element. In addition, the Al-B binary description was modified to account for the recent experimental work on the melting properties of AlB12. Two Ni-Al assessments are considered for the ternary assessment. For the same optimized ternary parameters, the two Ni-Al assessments produced similar results, with the differences increasing at high temperatures near the liquidus. C1 Natl Inst Stand & Technol, Div Met, Gaithersburg, MD 20899 USA. RP Campbell, CE (reprint author), Natl Inst Stand & Technol, Div Met, 100 Bur Dr,Stop 8555, Gaithersburg, MD 20899 USA. NR 50 TC 24 Z9 25 U1 4 U2 21 PU ASM INTERNATIONAL PI MATERIALS PARK PA SUBSCRIPTIONS SPECIALIST CUSTOMER SERVICE, MATERIALS PARK, OH 44073-0002 USA SN 1054-9714 J9 J PHASE EQUILIB JI J. Phase Equilib. PD OCT PY 1999 VL 20 IS 5 BP 485 EP 496 DI 10.1361/105497199770340743 PG 12 WC Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Chemistry; Materials Science; Metallurgy & Metallurgical Engineering GA 240GL UT WOS:000082817500006 ER PT J AU Hurley, DC AF Hurley, DC TI Nonlinear propagation of narrow-band Rayleigh waves excited by a comb transducer SO JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA LA English DT Article ID ACOUSTIC HARMONIC-GENERATION; ULTRASONIC PARAMETER; PLANE AB Quantitative experiments have been performed to measure the harmonic generation of narrow-band Rayleigh waves in aluminum. Based on a comparison of several methods, the Sokolinskii comb transducer was selected as an excitation source. Results are presented for narrow-band Rayleigh waves (center frequency 9.85 MHz) generated by the comb and detected with a path-stabilized Michelson interferometer. The on-axis, out-of-plane displacement amplitude was measured as a function of distance from the source. Maximum out-of-plane displacements greater than 7 nm were observed. An existing quasilinear theory that included both diffraction and attenuation was used to interpret the data. Values of the nonlinearity parameter beta(11) = 0.21-0.23 predicted displacements in good agreement with the data and were consistent with values for beta(11) calculated from literature values of the third-order elastic moduli of aluminum. [S0001-4966(99)03510-9]. C1 Natl Inst Stand & Technol, Boulder, CO 80303 USA. RP Hurley, DC (reprint author), Natl Inst Stand & Technol, 325 Broadway, Boulder, CO 80303 USA. NR 23 TC 20 Z9 20 U1 0 U2 7 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0001-4966 J9 J ACOUST SOC AM JI J. Acoust. Soc. Am. PD OCT PY 1999 VL 106 IS 4 BP 1782 EP 1788 DI 10.1121/1.427927 PN 1 PG 7 WC Acoustics; Audiology & Speech-Language Pathology SC Acoustics; Audiology & Speech-Language Pathology GA 244VK UT WOS:000083071300017 ER PT J AU Edgerton, SA Bian, X Doran, JC Fast, JD Hubbe, JM Malone, EL Shaw, WJ Whiteman, CD Zhong, S Arriaga, JL Ortiz, E Ruiz, M Sosa, G Vega, E Limon, T Guzman, F Archuleta, J Bossert, JE Elliot, SM Lee, JT McNair, LA Chow, JC Watson, JG Coulter, RL Doskey, PV Gaffney, JS Marley, NA Neff, W Petty, R AF Edgerton, SA Bian, X Doran, JC Fast, JD Hubbe, JM Malone, EL Shaw, WJ Whiteman, CD Zhong, S Arriaga, JL Ortiz, E Ruiz, M Sosa, G Vega, E Limon, T Guzman, F Archuleta, J Bossert, JE Elliot, SM Lee, JT McNair, LA Chow, JC Watson, JG Coulter, RL Doskey, PV Gaffney, JS Marley, NA Neff, W Petty, R TI Particulate air pollution in Mexico City: A collaborative research project SO JOURNAL OF THE AIR & WASTE MANAGEMENT ASSOCIATION LA English DT Article ID QUALITY AB PM10, PM2.5, precursor gas, and upper-air meteorological measurements were taken in Mexico City, Mexico, from February 23 to March 22, 1997 to understand concentrations and chemical compositions of the city's particulate matter (PM). Average 24-hr PM10 concentrations over the period of study at the core sites in the city were 75 mu g/m(3). The 24-hr standard of 150 mu g/m(3) was exceeded for seven samples taken during the study period; the maximum 24-hr concentration measured was 542 mu g/m(3). Nearly half of the PM10 was composed of fugitive dust from roadways, construction, and bare land. About 50% of the PM10 consisted of PM2.5, with higher percentages during the morning hours. Organic and black carbon constituted up to half of the PM2.5. PM concentrations were highest during the early morning and after sunset, when the mixed layers were shallow. Meteorological measurements taken during the field campaign show that on most days air was transported out of the Mexico City basin during the afternoon with little day-to-day carryover. C1 Pacific NW Natl Lab, Richland, WA 99352 USA. Inst Mexicano Petr, Mexico City 07730, DF, Mexico. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87544 USA. Univ Nevada, Desert Res Inst, Reno, NV 89506 USA. Argonne Natl Lab, Argonne, IL 60439 USA. Natl Ocean & Atmospher Adm, Boulder, CO 80303 USA. US Dept Energy, Germantown, MD USA. RP Edgerton, SA (reprint author), Pacific NW Natl Lab, Richland, WA 99352 USA. RI Watson, John/E-6869-2010; Neff, William/E-2725-2010; Sosa, Gustavo/F-3912-2015 OI Watson, John/0000-0002-1752-6899; Neff, William/0000-0003-4047-7076; Sosa, Gustavo/0000-0002-4980-3491 NR 32 TC 86 Z9 88 U1 2 U2 10 PU AIR & WASTE MANAGEMENT ASSOC PI PITTSBURGH PA ONE GATEWAY CENTER, THIRD FL, PITTSBURGH, PA 15222 USA SN 1047-3289 J9 J AIR WASTE MANAGE JI J. Air Waste Manage. Assoc. PD OCT PY 1999 VL 49 IS 10 BP 1221 EP 1229 PG 9 WC Engineering, Environmental; Environmental Sciences; Meteorology & Atmospheric Sciences SC Engineering; Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA 251KF UT WOS:000083444300008 PM 28060672 ER PT J AU Luecke, WE Wiederhorn, SM AF Luecke, WE Wiederhorn, SM TI A new model for tensile creep of silicon nitride SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Review ID HIGH-TEMPERATURE CREEP; GRAIN-BOUNDARY PHASE; SOLUTION-PRECIPITATION CREEP; STRESS RUPTURE BEHAVIOR; HOT-PRESSED SI3N4; COMPRESSIVE CREEP; LIQUID-PHASE; STRUCTURAL CERAMICS; SINTERED MATERIALS; GLASS-CERAMICS AB The tensile creep rate of most commercial grades of Si3N4 increases strongly with stress. Although the usual power-law functions can represent the creep data, the data often show curvature and systematic variations of slope with temperature and stress. In this article, we present a new approach to understanding the creep of ceramics, such as Si3N4, where a deformable second phase bonds a deformation-resistant major phase. A review of experimental data suggests that the rate of formation and growth of cavities in the second phase controls creep in these materials. The critical step for deformation is the redistribution of the second phase away from the cavitation site to the surrounding volume. The effective viscosity of the second phase and the density of active cavities determine the creep rate. Assuming that the hydrostatic stresses in pockets of the second phase are normally distributed leads to a model that accurately describes the tensile creep rate of grades of Si3N4, In this model, the creep rate increases exponentially with the applied stress, is independent of Si3N4 grain size, is inversely proportional to the effective viscosity of the deformable phase, and is proportional to the cube of the volume fraction of the deformable phase. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NR 109 TC 67 Z9 68 U1 0 U2 8 PU WILEY-BLACKWELL PI HOBOKEN PA 111 RIVER ST, HOBOKEN 07030-5774, NJ USA SN 0002-7820 EI 1551-2916 J9 J AM CERAM SOC JI J. Am. Ceram. Soc. PD OCT PY 1999 VL 82 IS 10 BP 2769 EP 2778 PG 10 WC Materials Science, Ceramics SC Materials Science GA 291XB UT WOS:000085763700030 ER PT J AU Zhang, YQ Held, IM AF Zhang, YQ Held, IM TI A linear stochastic model of a GCM's midlatitude storm tracks SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID GENERALIZED STABILITY THEORY; MIDWINTER SUPPRESSION; BAROCLINIC WAVES; TURBULENCE; OPERATORS; DYNAMICS; FLOWS AB A linear stochastic model is used to simulate the midlatitude storm tracks produced by an atmospheric GCM. A series of six perpetual insolation/SST GCM experiments are first performed for each month. These experiments capture the "midwinter suppression" of the Pacific storm track in a particularly clean way. The stochastic model is constructed by linearizing the GCM about its January climatology and finding damping and stirring parameters that best reproduce that model's eddy statistics. The model is tested by examining its ability to simulate other GCM integrations when the basic slate is changed to the mean how of those models, while keeping the stirring and damping unchanged. The stochastic model shows an impressive ability to simulate a variety of eddy statistics. It captures the midwinter suppression of the Pacific storm track qualitatively and is also capable of simulating storm track responses to El Nino. The model results are sensitive to the manner in which the model is stirred. Best results for eddy variances and fluxes are obtained by stirring the temperature and vorticity at low levels. However, a better simulation of the spatial structure of the dominant wave train as defined by covariance maps is obtained by stirring the temperature equation only, and at all levels. C1 Princeton Univ, NOAA, GFDL, Princeton, NJ 08542 USA. Princeton Univ, Program Atmospher & Ocean Sci, Princeton, NJ 08542 USA. RP Held, IM (reprint author), Princeton Univ, NOAA, GFDL, POB 308, Princeton, NJ 08542 USA. NR 17 TC 86 Z9 87 U1 0 U2 4 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 OCT 1 PY 1999 VL 56 IS 19 BP 3416 EP 3435 DI 10.1175/1520-0469(1999)056<3416:ALSMOA>2.0.CO;2 PG 20 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 244NC UT WOS:000083056800005 ER PT J AU Roberts, AP Garboczi, EJ AF Roberts, AP Garboczi, EJ TI Elastic properties of a tungsten-silver composite by reconstruction and computation SO JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS LA English DT Article DE microstructures; inhomogeneous material; finite elements; probability and statistics ID 3-DIMENSIONAL POROUS-MEDIA; GAUSSIAN RANDOM-FIELDS; 2-PHASE RANDOM-MEDIA; HETEROGENEOUS MATERIALS; TRANSPORT-PROPERTIES; MODEL; BOUNDS; MICROSTRUCTURE; SPHERE; ROCKS AB A three-dimensional model of a tungsten-silver composite is statistically constructed from an experimental two-dimensional image. The effective Young's modulus (E) of the model is computed in the temperature range 25-1060 degrees C using a finite element method. The results are in good agreement with experimental data. The reconstructed and overlapping sphere models are examples of bi-continuous (non-particulate) media. The computed moduli of the models are not generally in good agreement with the predictions of the self-consistent method. It has also been possible to evaluate the three-point variational bounds on the Young's moduli of the models using the results of Beran, Molyneux, Milton and Phan-Thien. The measured data were close to the upper bound if the properties of the two phases were similar (1/6 < E-1/E-2 < 6). (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Natl Inst Stand & Technol, Bldg Mat Div, Gaithersburg, MD 20899 USA. Univ Oxford, Dept Mat, Oxford OX1 3PH, England. Univ Queensland, Ctr Microscopy & Microanal, Brisbane, Qld 4072, Australia. RP Garboczi, EJ (reprint author), Natl Inst Stand & Technol, Bldg Mat Div, 100 Bur Dr Stop 8621, Gaithersburg, MD 20899 USA. RI Roberts, Anthony/A-3613-2011 OI Roberts, Anthony/0000-0001-5915-300X NR 49 TC 46 Z9 47 U1 1 U2 4 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0022-5096 J9 J MECH PHYS SOLIDS JI J. Mech. Phys. Solids PD OCT PY 1999 VL 47 IS 10 BP 2029 EP 2055 DI 10.1016/S0022-5096(99)00016-2 PG 27 WC Materials Science, Multidisciplinary; Mechanics; Physics, Condensed Matter SC Materials Science; Mechanics; Physics GA 238CX UT WOS:000082694300002 ER PT J AU O'Hara, TM Krahn, MM Boyd, D Becker, PR Philo, LM AF O'Hara, TM Krahn, MM Boyd, D Becker, PR Philo, LM TI Organochlorine contaminant levels in Eskimo harvested bowhead whales of Arctic Alaska SO JOURNAL OF WILDLIFE DISEASES LA English DT Article DE Balaena mysticetus; blubber; bowhead whale; liver; organochlorines; subsistence ID LAWRENCE-RIVER ESTUARY; DELPHINAPTERUS-LEUCAS; POLYCHLORINATED-BIPHENYLS; PERSISTENT ORGANOCHLORINES; PESTICIDES; MERCURY; QUEBEC; SEALS; INUIT; PCBS AB Organochlorine (OC) levels in liver and blubber of 20 bowhead whales (Balaena mysticetus) collected during the Eskimo subsistence harvest at Barrow (Alaska, USA) in 1992 and 1993 are presented. Liver sum DDT (Lipid weight) was significantly greater in male whales than in females. Most of the organochlorines measured were at higher levels in longer (older) than in shorter (younger) males. For female bowhead whales, hexachlorobenzene and lipid levels decreased and other OC levels did not change significantly with increasing length. Most organochlorine contaminants have low concentrations in tissues of the bowhead whale compared to concentrations in tissues of other cetaceans, especially Odontocetes. Based on allowable daily intakes (ADI) levels established by the Canadian Northern Contaminants Program (Ottawa, Ontario, Canada) "safe" levels of blubber to consume were calculated. Chlordane levels in bowhead whale blubber results in the most restrictive consumption amount (50 g blubber/day). We expect no adverse effects related to these organochlorine contaminants to occur in bowhead whales or in consumers of their tissues. However, investigation of low level chronic exposure effects and a more rigorous assessment of histopathology, biomarkers, and immune status in the bowhead whale would be required to conclude "no effect" with more certainty. C1 Dept Wildlife Management, Barrow, AK 99723 USA. NOAA, Natl Marine Fisheries Serv, Environm Consevat Div, Seattle, WA 98112 USA. Natl Inst Stand & Technol, Charleston, SC 29412 USA. RP O'Hara, TM (reprint author), Dept Wildlife Management, Box 69, Barrow, AK 99723 USA. NR 42 TC 30 Z9 31 U1 2 U2 9 PU WILDLIFE DISEASE ASSN, INC PI LAWRENCE PA 810 EAST 10TH ST, LAWRENCE, KS 66044-8897 USA SN 0090-3558 J9 J WILDLIFE DIS JI J. Wildl. Dis. PD OCT PY 1999 VL 35 IS 4 BP 741 EP 752 PG 12 WC Veterinary Sciences SC Veterinary Sciences GA 321VL UT WOS:000087475300013 PM 10574534 ER PT J AU Work, TM Balazs, GH AF Work, TM Balazs, GH TI Relating tumor score to hematology in green turtles with fibropapillomatosis in Hawaii SO JOURNAL OF WILDLIFE DISEASES LA English DT Article DE Chelonia mydas; fibropapillomatosis; field monitoring techniques; green turtle; hematology ID CHELONIA-MYDAS; BLOOD; SPIRORCHIDAE; ISLANDS AB The relationship between hematologic status and severity of tumor affliction in green turtles (Chelonia mydas) with fibropapillomatosis (FP) was examined. During 1 wk periods in July 1997 and July 1998, we bled 108 free-ranging green turtles from Pala'au (Molokai, Hawaii, USA) where FP is endemic. Blood was analyzed for hematocrit, estimated total solids, total white blood cell (WBC) count and differential WBC count. Each turtle was assigned a subjective tumor score ranging from a (no visible external tumors) to 3 (heavily tumored) that indicated the severity of FP. There was a progressive increase in monocytes and a decrease in all other hematologic parameters except heterophils and total numbers of white blood cells as tumor score increased. These data indicate that tumor score can relate to physiologic status of green turtles afflicted with FP, and that tumor score is a useful field monitor of severity of FP in this species. C1 US Geol Survey, Natl Wildlife Hlth Ctr, Biol Resource Div, Honolulu Field Stn, Honolulu, HI 96850 USA. NOAA, Natl Marine Fisheries Serv, SW Fisheries Sci Ctr, Honolulu Lab, Honolulu, HI 96822 USA. RP Work, TM (reprint author), US Geol Survey, Natl Wildlife Hlth Ctr, Biol Resource Div, Honolulu Field Stn, POB 50167, Honolulu, HI 96850 USA. RI Work, Thierry/F-1550-2015 OI Work, Thierry/0000-0002-4426-9090 NR 21 TC 50 Z9 56 U1 0 U2 4 PU WILDLIFE DISEASE ASSN, INC PI LAWRENCE PA 810 EAST 10TH ST, LAWRENCE, KS 66044-8897 USA SN 0090-3558 J9 J WILDLIFE DIS JI J. Wildl. Dis. PD OCT PY 1999 VL 35 IS 4 BP 804 EP 807 PG 4 WC Veterinary Sciences SC Veterinary Sciences GA 321VL UT WOS:000087475300025 PM 10574546 ER PT J AU McNamara, PT Caldarone, EM Buckley, LJ AF McNamara, PT Caldarone, EM Buckley, LJ TI RNA/DNA ratio and expression of 18S ribosomal RNA, actin and myosin heavy chain messenger RNAs in starved and fed larval Atlantic cod (Gadus morhua) SO MARINE BIOLOGY LA English DT Article ID HERRING CLUPEA-HARENGUS; HADDOCK MELANOGRAMMUS-AEGLEFINUS; PROTEIN-SYNTHESIS; GROWTH-RATES; DNA RATIO; FISH LARVAE; STARVATION; TEMPERATURE; STABILITY; MUSCLE AB Levels of total RNA, total DNA, 18S ribosomal RNA (rRNA), poly(A) messenger RNA (mRNA), and two mRNAs coding for abundant myofibrillar proteins were estimated in laboratory-reared Atlantic cod larvae (Gadus morhua Linnaeus) under conditions of feeding and starvation. DNA probes specific for cod 18S rRNA, beta-actin mRNA and myosin heavy chain mRNA were developed. In two experiments on newly hatched larvae in fed and starved treatments, changes in 18S rRNA and mRNA were similar to changes in total RNA during the first weeks after hatching. RNA levels in fed and starved larvae in both experiments were stable, or increased, over the first 3 d after hatching, and then decreased to minima at 9 d. RNA levels increased after 9 d, with the degree and timing of the increase varying among the individual classes of RNA. Complete mortality of starved larvae in both experiments was observed shortly after 11 d, corresponding to exhaustion of endogenous yolk reserves. Total RNA content, RNA/DNA ratio, 18S rRNA levels, total mRNA pool, and actin and myosin heavy chain mRNA levels showed significant differences in fed and starved first-feeding larvae after yolk exhaustion. In another experiment with 3- to 4-week-old cod larvae, 18S rRNA levels were significantly lower in starved versus fed larvae after 3 d. Total RNA responded to feeding and starvation within a similar time as 18S rRNA and the mRNAs examined. Analysis of bulk nucleic acids using fluorometric dyes was simpler and faster than analysis of individual RNAs using hybridization probes, and provides valuable information on recent growth and condition of individual larvae. However, analysis of specific RNAs can provide information on expression of the corresponding genes and reveal the changes underlying trends seen in bulk RNA. C1 Narragansett Lab, URI NOAA Cooperat Marine Educ & Res Program, Narragansett, RI 02882 USA. Univ Rhode Isl, Grad Sch Oceanog, Narragansett, RI 02882 USA. Natl Marine Fisheries Serv, NOAA, NE Fisheries Sci Ctr, Narragansett Lab, Narragansett, RI 02882 USA. RP Buckley, LJ (reprint author), Narragansett Lab, URI NOAA Cooperat Marine Educ & Res Program, Narragansett, RI 02882 USA. NR 46 TC 15 Z9 15 U1 2 U2 10 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0025-3162 J9 MAR BIOL JI Mar. Biol. PD OCT PY 1999 VL 135 IS 1 BP 123 EP 132 DI 10.1007/s002270050609 PG 10 WC Marine & Freshwater Biology SC Marine & Freshwater Biology GA 248ZJ UT WOS:000083306400015 ER PT J AU Valette-Silver, N AF Valette-Silver, N TI Special issue: Using sediments and biota to assess coastal and estuarine contamination - Preface SO MARINE ENVIRONMENTAL RESEARCH LA English DT Editorial Material C1 NOAA, NOS SI, SSMCH, Silver Spring, MD 20910 USA. Carnegie Inst Washington, Dept Terr Magnetism, Washington, DC 20015 USA. RP Valette-Silver, N (reprint author), NOAA, NOS SI, SSMCH, 10102,1305 E West Highway, Silver Spring, MD 20910 USA. NR 13 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0141-1136 J9 MAR ENVIRON RES JI Mar. Environ. Res. PD OCT-DEC PY 1999 VL 48 IS 4-5 BP 265 EP 267 DI 10.1016/S0141-1136(99)00073-2 PG 3 WC Environmental Sciences; Marine & Freshwater Biology; Toxicology SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Toxicology GA 249PP UT WOS:000083341700002 ER PT J AU Van Dolah, RF Hyland, JL Holland, AF Rosen, JS Snoots, TR AF Van Dolah, RF Hyland, JL Holland, AF Rosen, JS Snoots, TR TI A benthic index of biological integrity for assessing habitat quality in estuaries of the southeastern USA SO MARINE ENVIRONMENTAL RESEARCH LA English DT Article; Proceedings Paper CT 14th Biennial Estuarine Research Federation International Conference CY OCT, 1997 CL PROVIDENCE, RHODE ISLAND DE benthic index; contaminants; southeastern estuaries; sediment toxicity; EMAP ID CHESAPEAKE-BAY; B-IBI; RECOLONIZATION; MACROBENTHOS; SEDIMENTS AB A benthic index of biotic integrity was developed for use in estuaries of the southeastern USA (Cape Henry, VA; St. Lucie Inlet, FL) using a modification of the method developed by Weisberg et al. (1997. An estuarine benthic index of biotic integrity (B-IBI) for Chesapeake Bay. Estuaries, 20 (1), 149-158). Data from non-degraded stations sampled in 1993 and 1994 were analyzed using classification analysis of species composition to define major habitat types relative to selected physical parameters. Various benthic metrics were then tested on a larger 1994 data set for each major habitat to determine those that discriminated between nondegraded and degraded sites classified on the basis of dissolved oxygen, sediment chemistry, and sediment toxicity results. Scoring criteria for each metric were developed based on the distribution of values at non-degraded sites. Average scores from different combinations of the most sensitive metrics were compared to derive the final index, which integrates the average scores of four metrics (number of taxa, abundance, dominance, and percent sensitive taxa). An independent data set representing sites sampled in 1993 and 1995 was used to validate the index. The final combined index correctly classified 93% of stations province-wide in the developmental data set and 75% of stations in the validation data set. Comparison of the index results with those of individual benthic measures and sediment bioassays from stations sampled in 1993 and 1995 showed that the index detected a higher percentage of samples where bioeffects were expected (based on sediment chemistry) than did any of these other measures individually. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 SC Marine Resources Div, Charleston, SC 29422 USA. NOAA, Carolinian Prov Off, Charleston, SC 29422 USA. TPMC, Scituate, MA 02066 USA. RP Van Dolah, RF (reprint author), SC Marine Resources Div, POB 12559, Charleston, SC 29422 USA. NR 23 TC 95 Z9 100 U1 1 U2 12 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0141-1136 J9 MAR ENVIRON RES JI Mar. Environ. Res. PD OCT-DEC PY 1999 VL 48 IS 4-5 BP 269 EP 283 DI 10.1016/S0141-1136(99)00056-2 PG 15 WC Environmental Sciences; Marine & Freshwater Biology; Toxicology SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Toxicology GA 249PP UT WOS:000083341700003 ER PT J AU Valette-Silver, NJ Riedel, GF Crecelius, EA Windom, H Smith, RG Dolvin, SS AF Valette-Silver, NJ Riedel, GF Crecelius, EA Windom, H Smith, RG Dolvin, SS TI Elevated arsenic concentrations in bivalves from the southeast coasts of the USA SO MARINE ENVIRONMENTAL RESEARCH LA English DT Article; Proceedings Paper CT 14th Biennial Estuarine Research Federation International Conference CY OCT, 1997 CL PROVIDENCE, RI DE arsenic; southeast USA; bivalves; sediments; bioaccumulation ID NATURAL-WATERS; RIVER ESTUARY; UNITED-STATES; MUSSEL-WATCH; TRACE-METALS; SEDIMENTS; SELENIUM; CYCLE; BIOGEOCHEMISTRY; SPECIATION AB Since 1986, the National Oceanic and Atmospheric Administration (NOAA) National Status and Trends (NS&T) Program, Mussel Watch Project (MWP) has been analyzing contaminants in bivalves (oysters and mussels) collected along the coastal USA. Compared to the rest of the USA, the oysters collected from sites located along the southeastern coasts, from North Carolina to the Florida panhandle, display high concentrations of arsenic (As) in their soft tissues. In this area, As concentrations can be elevated in sediments and in bivalves, although exact spatial correspondence between the two is infrequent. As concentrations in waters and food (plankton and suspended particles) directly surrounding the mollusks collected in winter are not unusually high. Phosphate deposits and soil pesticide residues are the hypothesized main sources of this As, and the enrichment mechanism appears to result from a mixture of processes including atmospheric deposition, river and aquifer inputs, and ocean up-welling. In the southeast oysters, the large bio-accumulation of As may also be affected by the seasonal cycle of adsorption/solubilization of As observed in several estuarine and coastal areas, by local physico-chemical parameters such as temperature, salinity, and the nature of sediments (e.g. high contents in iron, calcium, phosphate, and organic material). Even at these very high concentrations, the As present in the southeastern oysters does not appear to present a health threat to humans or to marine life. Published by Elsevier Science Ltd. C1 Natl Acad Sci, Estuarine Res Ctr, St Leonard, MD 20685 USA. Battelle Mem Inst, Marine Sci Lab, Sequim, WA 98382 USA. Skidaway Inst Oceanog, Savannah, GA 31411 USA. Carnegie Inst Washington, Dept Terr Magnetism, Washington, DC 20015 USA. NOAA, NOS, ORCA, Silver Spring, MD 20910 USA. RP Valette-Silver, NJ (reprint author), NOAA, NOS, SI, 1305 East West Highway, Silver Spring, MD 20910 USA. EM nathalie.valette-silver@noaa.gov NR 107 TC 51 Z9 53 U1 2 U2 11 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0141-1136 J9 MAR ENVIRON RES JI Mar. Environ. Res. PD OCT-DEC PY 1999 VL 48 IS 4-5 BP 311 EP 333 DI 10.1016/S0141-1136(99)00057-4 PG 23 WC Environmental Sciences; Marine & Freshwater Biology; Toxicology SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Toxicology GA 249PP UT WOS:000083341700005 ER PT J AU Anderson, JW Jones, JM Hameedi, J Long, E Tukey, RH AF Anderson, JW Jones, JM Hameedi, J Long, E Tukey, RH TI Comparative analysis of sediment extracts from NOAA's bioeffects studies by the biomarker, P450 Reporter Gene System SO MARINE ENVIRONMENTAL RESEARCH LA English DT Article; Proceedings Paper CT 14th Biennial Estuarine Research Federation International Conference CY OCT, 1997 CL PROVIDENCE, RI DE biomarker; P450 Reporter Gene System; sediments; contaminants ID TOXIC EQUIVALENCY FACTORS; RAINBOW-TROUT; CONGENERS; EXPOSURE; DIOXIN; FISH AB Sediment samples collected from nine coastal and estuarine areas have been analyzed to determine response of a biomarker, P450 Reporter Gene System (RGS). This biomarker, using a transgenic cell line, detects the presence and potency of organic compounds that typically induce the CYP1A gene. Previous investigations have shown that sediments containing chemicals which produce a response of 60 or more mu g/g of benzo[a]pyrene equivalents (B[a]PEq) also exhibited a degraded community structure. RGS data from all study areas combined (527 samples) show that the mean response is 22.7 mu g/g B[a]PEq, and the mean upper 99% confidence interval is 32. We believe that sediments exhibiting B[a]PEq values of 32-50 are possibly contaminated to the extent that effects on benthic organisms may be observed, and those producing an RGS response of 60 and greater are likely to contain levels of chemicals that will produce chronic toxicity. The majority of the stations investigated produced responses below 32 mu g/g B[a]PEq. No samples from coastal southern California produced responses greater than 39. However, samples producing induction over 60 mu g/g B[a]PEq were: 50%, San Diego Bay; 16%, Delaware Bay; 8%, Sabine Lake; 4%, Northern Puget Sound; and 3%, Charleston Harbor. A strong statistical correlation was observed between the RGS responses and high molecular weight polycyclic aromatic hydrocarbon concentrations in the sediments from several of the study areas. Of the 2694 km(2) encompassed in the surveys, only 0.42% of the area exhibited responses above 32 mu g/g B[a]PEq, which represented 11.4 km(2). This assay is useful in identifying high levels of toxic and carcinogenic compounds in the sediments and predicting the potential impact of these chemicals on the biological community. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Columbia Analyt Serv, Vista, CA 92083 USA. NOAA, Bioeffects Brand, Silver Spring, MD 20910 USA. Univ Calif San Diego, Dept Chem Biochem & Pharmacol, La Jolla, CA 92093 USA. RP Anderson, JW (reprint author), Columbia Analyt Serv, 1185 Pk Ctr Dr,Suite A, Vista, CA 92083 USA. EM jaanderson@kelso.caslab.com NR 25 TC 15 Z9 15 U1 0 U2 0 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0141-1136 J9 MAR ENVIRON RES JI Mar. Environ. Res. PD OCT-DEC PY 1999 VL 48 IS 4-5 BP 407 EP 425 DI 10.1016/S0141-1136(99)00055-0 PG 19 WC Environmental Sciences; Marine & Freshwater Biology; Toxicology SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Toxicology GA 249PP UT WOS:000083341700010 ER PT J AU Jaramillo-Legorreta, AM Rojas-Bracho, L Gerrodette, T AF Jaramillo-Legorreta, AM Rojas-Bracho, L Gerrodette, T TI A new abundance estimate for vaquitas: First step for recovery SO MARINE MAMMAL SCIENCE LA English DT Article DE vaquita; Phocoena sinus; abundance; line-transect; Gulf of California; endangered species ID PHOCOENA-SINUS; NORTHERN GULF; CALIFORNIA; CETACEA; AERIAL AB A line-transect survey specifically designed to estimate vaquita (Phocoena sinus) abundance over its entire range was carried out by three boats in the summer of 1997. There was a total of 125 sightings of vaquita groups, mainly due to the use of large 25x150 binoculars, which were seven times more effective in detecting vaquitas than hand-held 7X binoculars. Results confirmed that the range of the vaquita is restricted to the northwestern corner of the Gulf of California, Mexico, but that the boundaries of the Upper Gulf of California and Colorado River Delta Biosphere Reserve do not correspond well with the distribution of vaquitas. The shallow water north of the town of San Felipe was found to have a higher density of animals than had been indicated by previous surveys. The total population site was estimated to be 567 animals, with a 95% confidence interval from 177 to 1,073. This estimate is an improvement over previous estimates, which had low numbers of sightings, relied on parameters taken from other species, and/or did not cover all areas where vaquitas could potentially be found. The 1997 estimate was more than twice the 1993 estimate, but there are several reasons why the numbers cannot be directly compared, and it should not be concluded the population is increasing. This first complete estimate of vaquita abundance can be a beginning for the recovery of this highly endangered species. C1 UABC, Inst Nacl Pesca, Fac Ciencias Marinas, Programa Nacl Invest & Conservac Mamiferos Marino, Ensenada 22800, Baja California, Mexico. NOAA, Natl Marine Fisheries Serv, SW Fisheries Sci Ctr, La Jolla, CA 92038 USA. RP Jaramillo-Legorreta, AM (reprint author), UABC, Inst Nacl Pesca, Fac Ciencias Marinas, Programa Nacl Invest & Conservac Mamiferos Marino, Km 103 Carretera Tij Ens, Ensenada 22800, Baja California, Mexico. NR 29 TC 32 Z9 33 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 OCT PY 1999 VL 15 IS 4 BP 957 EP 973 DI 10.1111/j.1748-7692.1999.tb00872.x PG 17 WC Marine & Freshwater Biology; Zoology SC Marine & Freshwater Biology; Zoology GA 250RP UT WOS:000083402100015 ER PT J AU Rojas-Bracho, L Taylor, BL AF Rojas-Bracho, L Taylor, BL TI Risk factors affecting the vaquita (Phocoena sinus) SO MARINE MAMMAL SCIENCE LA English DT Article DE risk factors; vaquita; Phocoena sinus; bycatch; pollution; inbreeding depression; productivity ID EFFECTIVE POPULATION-SIZE; COLORADO RIVER DELTA; LIFE-HISTORY; CONSERVATION; CALIFORNIA; GENERATIONS; DEMOGRAPHY; WHALES; WATERS; MEXICO AB Despite the vaquita being commonly cited as one of the most endangered marine mammals in the world, there is still disagreement over which factors put the species at greatest risk of extinction. This lack of agreement hinders management decisions needed to reduce the risk to the species. To expedite decision-making we consider four major risk factors. Habitat alteration from reduced flow of the Colorado River does not currently appear to be a risk factor because productivity remains high in vaquita habitat. Pollutant loads are low and pose low to no risk. Reduced fitness from inbreeding depression and loss of genetic variability are unlikely to pose high risk currently, though risk will increase if vaquitas remain at low abundance over long periods of time. Mortality resulting from fisheries bycatch poses high risk. Thus, short term management should not be hindered by uncertainty in estimating the risk of these factors, and primary conservation efforts should be directed towards immediate elimination of incidental fishery mortality. C1 Univ Autonoma Baja California, Fac Ciencias Marinas, Programa Nacl Mamiferos Marinos, Ensenada 22800, Baja California, Mexico. SW Fisheries Sci Ctr, La Jolla, CA 92038 USA. RP Rojas-Bracho, L (reprint author), Univ Autonoma Baja California, Fac Ciencias Marinas, Programa Nacl Mamiferos Marinos, Km 103 Carretera Tijuana Ensenda, Ensenada 22800, Baja California, Mexico. EM lrojas@ucsd.edu NR 72 TC 27 Z9 29 U1 9 U2 40 PU WILEY-BLACKWELL PI HOBOKEN PA 111 RIVER ST, HOBOKEN 07030-5774, NJ USA SN 0824-0469 EI 1748-7692 J9 MAR MAMMAL SCI JI Mar. Mamm. Sci. PD OCT PY 1999 VL 15 IS 4 BP 974 EP 989 DI 10.1111/j.1748-7692.1999.tb00873.x PG 16 WC Marine & Freshwater Biology; Zoology SC Marine & Freshwater Biology; Zoology GA 250RP UT WOS:000083402100016 ER PT J AU Rosel, PE Rojas-Bracho, L AF Rosel, PE Rojas-Bracho, L TI Mitochondrial DNA variation in the critically endangered vaquita Phocoena sinus Norris and Macfarland, 1958 SO MARINE MAMMAL SCIENCE LA English DT Article DE conservation genetics; control region; mtDNA ID WHALES EUBALAENA-GLACIALIS; POPULATION-STRUCTURE; GENETIC-VARIATION; LIFE-HISTORY; CONSERVATION; MUTATION; CETACEA; DIFFERENTIATION; MICROSATELLITES; DIVERSITY AB The vaquita, Phocoena sinus, is one of two critically endangered cetacean species, and is listed as an endangered species in both the United States and Mexico. These listings result from a small population size, estimated to be 224 animals, and a rapid decline in abundance (18% per annum) thought to be caused by human activities. To characterize the genetic composition of the vaquita, we have sequenced a portion of the mitochondrial DNA control region from 43 individuals collected between 1985 and 1993. All animals had identical sequences. While low genetic variability has been reported for cetacean species, this complete lack of polymorphism in the control region is unique. This result is concordant with the hypothesis that the evolutionary history of the species includes a bottleneck or founder event, possibly at species inception, followed by a small long-term effective population size. We recommend parallel studies of nuclear variability, which could provide understanding of the basic biology of the vaquita for use in conservation efforts. C1 Univ Calif San Diego, Scripps Inst Oceanog, San Diego, CA 92093 USA. Univ New Hampshire, Dept Zool, Durham, NH 03824 USA. Univ Autonoma Baja California, Fac Ciencias Marinas, Programa Nacl Mamiferos Marinos, Inst Nacl Pesca, Ensenada 22800, Baja California, Mexico. SW Fisheries Sci Ctr, La Jolla, CA 92038 USA. RP Rosel, PE (reprint author), Natl Ocean Serv, 219 Fort Johnson Rd, Charleston, SC 29412 USA. NR 69 TC 22 Z9 30 U1 4 U2 13 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 OCT PY 1999 VL 15 IS 4 BP 990 EP 1003 DI 10.1111/j.1748-7692.1999.tb00874.x PG 14 WC Marine & Freshwater Biology; Zoology SC Marine & Freshwater Biology; Zoology GA 250RP UT WOS:000083402100017 ER PT J AU Taylor, BL Rojas-Bracho, L AF Taylor, BL Rojas-Bracho, L TI Examining the risk of inbreeding depression in a naturally rare cetacean, the vaquita (Phocoena sinus) SO MARINE MAMMAL SCIENCE LA English DT Article DE genetic diversity; inbreeding depression; mitochondrial DNA; Phocoena sinus; rare species; risk assessment; risk of extinction; vaquita ID EFFECTIVE POPULATION-SIZE; CONSERVATION; GENERATIONS; DEMOGRAPHY; EVOLUTION; SELECTION AB Uncertainty about the magnitude of various risks facing endangered species can paralyze conservation action. The vaquita is a naturally rare porpoise that has declined to the low hundreds of individuals because of gillnet mortality over the past 57 years. No variability in mitochondrial DNA (mtDNA) was found in vaquitas (n = 43). Because reducing gillnet mortality will require strong conservation action, the question was raised whether vaquitas are doomed because of inbreeding depression and whether, therefore, mitigation efforts would be futile. We use simulations to investigate the "doom hypothesis" by first asking whether the current level of genetic variability results from the recent decline or from historical factors. If fixation was historical then deleterious alleles could have been selected out of vaquitas over thousands of years, reducing concerns about inbreeding depression. Simulations showed that fixation most likely resulted from historical rather than recent loss. Of 1,000 simulations done at plausible abundances and mutation rates, 247 (84.3%) fixed before and 46 (15.7%) fixed during the recent decline. Fixation correlates with historical abundance, making it more likely that because vaquitas are fixed, they are also a naturally rare species. However, because studies on purging deleterious alleles have nor shown purging to be universally beneficial we also examine the doom hypothesis using data on the response to inbreeding of a wide variety of captive animals. Responses are so variable that the doom hypothesis cannot be affirmed. We further explore whether more data from vaquitas would lead to conclusive results and found that the data required, such as the adult survival rate, will be impossible to obtain. We conclude that because the doom hypothesis cannot be affirmed this risk factor should not delay conservation actions. C1 SW Fisheries Sci Ctr, La Jolla, CA 92038 USA. Univ Autonoma Baja California, Programa Nacl Mamiferos, Marinos Fac Ciencias Marinas, Inst Nacl Pesca, Ensenada 22800, Baja California, Mexico. SW Fisheries Sci Ctr, La Jolla, CA 92038 USA. RP Taylor, BL (reprint author), SW Fisheries Sci Ctr, POB 271, La Jolla, CA 92038 USA. EM taylor@caliban.ucsd.edu NR 47 TC 13 Z9 15 U1 9 U2 21 PU WILEY-BLACKWELL PI HOBOKEN PA 111 RIVER ST, HOBOKEN 07030-5774, NJ USA SN 0824-0469 EI 1748-7692 J9 MAR MAMMAL SCI JI Mar. Mamm. Sci. PD OCT PY 1999 VL 15 IS 4 BP 1004 EP 1028 DI 10.1111/j.1748-7692.1999.tb00875.x PG 25 WC Marine & Freshwater Biology; Zoology SC Marine & Freshwater Biology; Zoology GA 250RP UT WOS:000083402100018 ER PT J AU Perrin, WF Dolar, MLL Robineau, D AF Perrin, WF Dolar, MLL Robineau, D TI Spinner dolphins (Stenella longirostris) of the western Pacific and Southeast Asia: Pelagic and shallow-water forms SO MARINE MAMMAL SCIENCE LA English DT Article DE Stenella longirostris; Delphinus roseiventris; spinner dolphin; taxonomy; morphology; subspecies; geographical variation; feeding habits; Southeast Asia; Australia; Philippines AB A dwarf form of the spinner dolphin has been reported from the Gulf of Thailand, while more typical large spinner dolphins have been described from Japanese waters and other localities in the western Pacific. These reports have been based on very few specimens. Our purpose in this study was to determine the affinities of spinner dolphins throughout the region based on larger samples and to review their taxonomic status, with an hypothesis of two widespread ecotypic forms, or subspecies. We examined 213 osteological specimens, from a tuna gillnet fishery in the Philippines, from the former Taiwanese shark gillnet fishery in the Timer and Arafura Seas off northern Australia, from the Gulf of Thailand, from other areas in the western Pacific and Southeast Asia, from the eastern Indian Ocean, and from the Central and South Pacific. Results show that spinner dolphins from the deep inner waters of the Philippines conform to the large pelagic type of spinner dolphin that inhabits the Central and South Pacific, the western Pacific and the eastern Indian Ocean. The skull is similar in size and shape to the holotype specimen of S. langirostris (from unknown locality). This form feeds primarily on small mesopelagic fishes and squids. Spinner dolphins from the shallow waters of inner Southeast Asia represented in the sample, including the Gulf of Thailand, Timer Sea and Arafura Sea, are smaller in body and skull size, have fewer teeth and vertebrae, and feed mainly on benthic and coral reef fishes and invertebrates. We hypothesize that this form also inhabits the Java Sea and other shallow waters throughout inner Indonesia and Malaysia. We redescribe a subspecies corresponding to the small form and based pn Delphinus roseiventris Wagner 1846 from the Arafura Sea, designating a neotype and paraneotype specimens. C1 NOAA, Natl Marine Fisheries Serv, SW Fisheries Sci Ctr, La Jolla, CA 92038 USA. Univ Calif San Diego, Scripps Inst Oceanog, Ctr Marine Biotechnol & Biomed, La Jolla, CA 92093 USA. Museum Natl Hist Nat, Anat Comparee Lab, F-75005 Paris, France. RP Perrin, WF (reprint author), NOAA, Natl Marine Fisheries Serv, SW Fisheries Sci Ctr, POB 271, La Jolla, CA 92038 USA. NR 30 TC 31 Z9 36 U1 2 U2 8 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 OCT PY 1999 VL 15 IS 4 BP 1029 EP 1053 DI 10.1111/j.1748-7692.1999.tb00876.x PG 25 WC Marine & Freshwater Biology; Zoology SC Marine & Freshwater Biology; Zoology GA 250RP UT WOS:000083402100019 ER PT J AU Hohn, AA Fernandez, S AF Hohn, AA Fernandez, S TI Biases in dolphin age structure due to age estimation technique SO MARINE MAMMAL SCIENCE LA English DT Article DE age estimation; age structure; lifespan; longevity; tooth preparation techniques; bottlenose dolphin; Tursiops truncatus ID TURSIOPS-TRUNCATUS; GROWTH AB The use of different tooth-preparation techniques resulted in widely different estimates of age in a sample of bottlenose dolphins, Tursiops truncatus. Teeth from 30 animals were prepared using the two-most prevalent techniques reported in the literature for this species, unstained sections and decalcified and stained thin sections, and the resulting paired counts of growth layers were compared. Estimates from the two methods were identical or at least placed the specimen in the same age class in only five cases, ranging in age from 2 to 22 yr. Otherwise, the results fell into one of two categories: when the estimates were close (less than or equal to 3-yr difference, n = 15), counts from unstained sections generally were higher (13 cases, age from unstained sections 2-20 yr); when the counts were more disparate, estimates from stained sections always were higher (6-31 yr difference, n = 10, age from unstained sections 12-27 yr and corresponding ages from stained sections of 27-47). Previous studies of age estimation in known-age bottlenose dolphins indicate that stained sections allow accurate estimates of age and demonstrate that maximum lifespan approaches or exceeds 50 yr. In contrast, the results herein suggest that using unstained sections for age estimation may result in imprecise or biased age-structure data. C1 Natl Marine Fisheries Serv, Off Protected Resources, Silver Spring, MD 20910 USA. Dolphin Biol Res Inst, Marine Mammal Program, Smithsonian Inst, Washington, DC 20560 USA. RP Hohn, AA (reprint author), NOAA, Natl Marine Fisheries Serv, SE Fisheries Sci Ctr, 101 Pivers Isl Rd, Beaufort, NC 28516 USA. RI Hohn, Aleta/G-2888-2011 OI Hohn, Aleta/0000-0002-9992-7062 NR 22 TC 15 Z9 16 U1 0 U2 4 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 OCT PY 1999 VL 15 IS 4 BP 1124 EP 1132 DI 10.1111/j.1748-7692.1999.tb00881.x PG 9 WC Marine & Freshwater Biology; Zoology SC Marine & Freshwater Biology; Zoology GA 250RP UT WOS:000083402100024 ER PT J AU Watkins, WA Daher, MA DiMarzio, NA Samuels, A Wartzok, D Fristrup, KM Gannon, DP Howey, PW Maiefski, RR Spradlin, TR AF Watkins, WA Daher, MA DiMarzio, NA Samuels, A Wartzok, D Fristrup, KM Gannon, DP Howey, PW Maiefski, RR Spradlin, TR TI Sperm whale surface activity from tracking by radio and satellite tags SO MARINE MAMMAL SCIENCE LA English DT Article DE sperm whale; Physeter catodon; surface activity; diving; tracking; radio track; telemetry; satellite track; ARGOS ID PHYSETER-MACROCEPHALUS; GALAPAGOS-ISLANDS; DIVING BEHAVIOR; VOCALIZATIONS; CATODON; SONAR AB Three 12-m sperm whales (Physeter catodon) were tagged and tracked west of Dominica in the southeast Caribbean to follow the surfacing patterns and movements of these presumed subadult males. Whale N was tagged in April 1993 with a 30-MHz radio tag and tracked for two days. Whale H was tagged in April 1995 with a 30-MHz radio tag and tracked for 4.6 d. Whale A was tagged in April 1995 with a satellite-monitored tag tracked by ARGOS for 21.5 d, the first four of which were concurrent with the tracking of Whale H, an associate. The tagged whales remained west of Dominica for at least 2, 5, and 13 d, respectively. Whales N and A then moved southward to waters off Martinique. There were no apparent effects on the whales by tagging or the presence of the tags. The whales averaged speeds of 2.6-3.5 km/h. Surfacings, indicated by tag signals, were of two types: short surfacings apparently primarily for respiration, averaging 7-10.5 min between repeated longer dives, occurring day and night; and extended surfacings :seemingly for rest and social interactions with conspecifics, occurring mostly in daylight. Whales were near the surface for 20.4%-22.6% of the total time (26.6%-27.1% during the day and 14.9%-17.1% at night). Delayed blowing was observed as Whale N surfaced for 8.3 min between 47- and 45-min dives but delayed the first of its 31 blows for 1.5 min after surfacing. C1 Woods Hole Oceanog Inst, Woods Hole, MA 02543 USA. Chicago Zool Soc, Donald F & Ada L Rice Conservat Biol & Res, Brookfield, IL 60513 USA. Cornell Univ, Ithaca, NY 14850 USA. Microwave Telemetry Inc, Columbia, MD 21046 USA. Maiefski, Oceanside, CA 92056 USA. NMFS, Off Protected Species, Silver Spring, MD 20910 USA. RP Watkins, WA (reprint author), Woods Hole Oceanog Inst, Woods Hole, MA 02543 USA. NR 39 TC 21 Z9 21 U1 0 U2 10 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 OCT PY 1999 VL 15 IS 4 BP 1158 EP 1180 DI 10.1111/j.1748-7692.1999.tb00883.x PG 23 WC Marine & Freshwater Biology; Zoology SC Marine & Freshwater Biology; Zoology GA 250RP UT WOS:000083402100026 ER PT J AU Weller, DW Wursig, B Bradford, AL Burdin, AM Blokhin, SA Minakuchi, H Brownell, RL AF Weller, DW Wursig, B Bradford, AL Burdin, AM Blokhin, SA Minakuchi, H Brownell, RL TI Gray whales (Eschrichtius robustus) off Sakhalin Island, Russia: Seasonal and annual patterns of occurrence SO MARINE MAMMAL SCIENCE LA English DT Article DE western gray whale; Eschrichtius robustus; Okhotsk Sea; Russia; photo-identification; occurrence patterns; site fidelity AB The annual return, seasonal occurrence, and site fidelity of Korean-Okhotsk or western gray whales on their feeding grounds off northeastern Sakhalin Island, Russia, were assessed by boat-based photo-identification studies in 1994-1998. A total of 262 pods were observed, ranging in size from 1 to 9 whales with an overall mean of 2.0. Sixty-nine whales were individually identilled, and a majority of all whales (71.0%) were observed in multiple years. Annual sighting frequencies ranged from 1 to 18 d, with a mean of 5.4 d. The percentage of whales reidentified from previous years showed a continuous annual increase, reaching 87.0% by the end of the study. Time between first and last sighting of identified individuals within a given year was 1-85 d, with an overall mean of 40.6 d. Annual calf proportions ranged from 4.3% (1997) to 13.2% (1998), and mother-calf separations generally occurred between July and September. The seasonal site fidelity and annual return of whales to this pare of the Okhotsk Sea emphasize its importance: as a primary feeding ground for this endangered population. C1 Texas A&M Univ, Marine Mammal Res Program, Galveston, TX 77551 USA. Kamchatka Inst Ecol & Nat Management, Kamcharka 683000, Russia. Pacific Inst Fisheries & Oceanog, Vladivostok 690600, Russia. CETUS, Yokohama, Kanagawa 245, Japan. Natl Marine Fisheries Serv, SW Fisheries Sci Ctr, La Jolla, CA 92038 USA. RP Weller, DW (reprint author), Natl Marine Fisheries Serv, SW Fisheries Sci Ctr, POB 271, La Jolla, CA 92038 USA. NR 42 TC 19 Z9 25 U1 0 U2 9 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 OCT PY 1999 VL 15 IS 4 BP 1208 EP 1227 DI 10.1111/j.1748-7692.1999.tb00886.x PG 20 WC Marine & Freshwater Biology; Zoology SC Marine & Freshwater Biology; Zoology GA 250RP UT WOS:000083402100029 ER PT J AU Stafford, KM Nieukirk, SL Fox, CG AF Stafford, KM Nieukirk, SL Fox, CG TI An acoustic link between blue whales in the eastern tropical Pacific and the northeast Pacific SO MARINE MAMMAL SCIENCE LA English DT Article DE blue whale; Balaenoptera musculus; distribution; migration; acoustics ID BALAENOPTERA-MUSCULUS; FUCA RIDGE; CALIFORNIA; WATERS; JUAN AB Blue whale calls in the eastern North Pacific Ocean consist of a two-part call often termed the A-B call. This call has been described for regions offshore of Oregon, Washington, and California, USA and the Sea of Cortez, Mexico (reviewed in Rivers 1997). Data collected from moored hydrophones in the eastern tropical Pacific (ETP) indicate that the A-B pattern is common in this region as well. There is consistency in this call type throughout the eastern North Pacific and throughout the year. This acoustic evidence indicates continuity between blue whales in the ETP and those found west of North America. The acoustic data suggest that the population of blue whales generally referred to as the "California/Mexico'' stock might better be termed the "northeast Pacific" stock of blue whales. C1 Oregon State Univ, Hatfield Marine Sci Ctr, COAS, CIMRS, Newport, OR 97365 USA. NOAA, Hatfield Marine Sci Ctr, PMEL, Newport, OR 97365 USA. RP Stafford, KM (reprint author), Oregon State Univ, Hatfield Marine Sci Ctr, COAS, CIMRS, 2030 S Marine Sci Dr, Newport, OR 97365 USA. NR 29 TC 36 Z9 41 U1 3 U2 5 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 OCT PY 1999 VL 15 IS 4 BP 1258 EP 1268 DI 10.1111/j.1748-7692.1999.tb00889.x PG 11 WC Marine & Freshwater Biology; Zoology SC Marine & Freshwater Biology; Zoology GA 250RP UT WOS:000083402100032 ER PT J AU Walker, WA Hanson, MB AF Walker, WA Hanson, MB TI Biological observations ow Stejneger's beaked whale, Mesoplodon stejnegeri, from strandings on Adak Island, Alaska SO MARINE MAMMAL SCIENCE LA English DT Article C1 Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr, Natl Marine Mammal Lab, NOAA, Seattle, WA USA. RP Walker, WA (reprint author), Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr, Natl Marine Mammal Lab, NOAA, 7600 Sand Point Way NE, Seattle, WA USA. EM mindwalk@msn.com NR 34 TC 14 Z9 17 U1 1 U2 1 PU WILEY-BLACKWELL PI HOBOKEN PA 111 RIVER ST, HOBOKEN 07030-5774, NJ USA SN 0824-0469 EI 1748-7692 J9 MAR MAMMAL SCI JI Mar. Mamm. Sci. PD OCT PY 1999 VL 15 IS 4 BP 1314 EP 1329 DI 10.1111/j.1748-7692.1999.tb00893.x PG 16 WC Marine & Freshwater Biology; Zoology SC Marine & Freshwater Biology; Zoology GA 250RP UT WOS:000083402100036 ER PT J AU Martys, NS AF Martys, NS TI Diffusion in partially-saturated porous materials SO MATERIALS AND STRUCTURES LA English DT Article ID PHASE-TRANSITIONS; BOLTZMANN METHOD; MEDIA; PERMEABILITY; SIMULATION; TRANSPORT; EQUATION; MODELS AB The diffusive transport of ions in two classes of porous media was studied as a function of fluid saturation and wetting properties. A lattice Boltzmann method was used to model phase separation of a binary mixture, including wetting effects, in porous media. Diffusive transport is then evaluated in each separate phase. It is found that the degree of saturation of each phase can strongly affect the transport of ions that are limited to diffusing in either the wetting or non-wetting phase. At high saturations, good agreement is found between our estimates of diffusivity and that predicted by the semi-empirical Archie's second law. At lower saturations it is found that Archie's second law breaks down as percolation effects become important. C1 Natl Inst Stand & Technol, Bldg Mat Div, Bldg & Fire Res Lab, Gaithersburg, MD 20899 USA. RP Martys, NS (reprint author), Natl Inst Stand & Technol, Bldg Mat Div, Bldg & Fire Res Lab, 226-B350, Gaithersburg, MD 20899 USA. NR 18 TC 46 Z9 46 U1 0 U2 8 PU R I L E M Publications PI cachan cedex PA 61 ave president wilson, 94235 cachan cedex, FRANCE SN 0025-5432 J9 MATER STRUCT JI Mater. Struct. PD OCT PY 1999 VL 32 IS 222 BP 555 EP 562 DI 10.1007/BF02480489 PG 8 WC Construction & Building Technology; Engineering, Civil; Materials Science, Multidisciplinary SC Construction & Building Technology; Engineering; Materials Science GA 247MN UT WOS:000083224700002 ER PT J AU Lau, NC Nath, MJ AF Lau, NC Nath, MJ TI Observed and GCM-simulated westward-propagating, planetary-scale fluctuations with approximately three-week periods SO MONTHLY WEATHER REVIEW LA English DT Article ID NORTHERN-HEMISPHERE; ROSSBY WAVES; FREQUENCY; DISTURBANCES; CIRCULATION; VARIABILITY; MODES; EAST; ATMOSPHERE; REANALYSIS AB The structural characteristics and vorticity dynamics of westward-traveling patterns (WTP) in the troposphere are examined using the National Centers for Environmental Prediction-National Center for Atmospheric Research (NCEP-NCAR) reanalyses based on observations for the 1973-95 period, as well as the output from a 100-yr integration of a general circulation model (GCM) with a rhomboidal truncation at 30 wavenumbers and 14 vertical levels. An identical set of diagnostic tools, including progressive/retrogressive variance analysis, cross-spectra, and complex empirical orthogonal functions (EOFs), are applied to the reanalysis and GCM datasets for 300-mb height. These diagnoses all indicate that the WTP are most prominent during the cold season in the high-latitude zone extending westward from northwestern Canada to northeastern Siberia, with a typical period of similar to 22 days. Outstanding episodes are identified an the basis of the temporal coefficients of the leading complex EOF. Composite charts of the anomalous 300-mb height, sea level pressure, and 850-mb temperature fields at various phases of these events are constructed. The typical circulation changes accompanying the passage of the WTP are similar to those associated with well-known regional weather phenomena such as amplified pressure ridges over Alaska, cold air outbreaks over western North America and east Asia, and heavy snowfall over the Pacific Northwest. The occurrence of the WTP over the North Pacific is also characterized by notable changes in the spatial distribution and intensity of synoptic scale activity. The contributions of relative vorticity advection, planetary vorticity advection (the "beta effect"), and horizontal divergence to the vorticity tendency in various phases of the composite wave at 300, 500, and 850 mb are investigated. In the mid- and upper troposphere, the vorticity dynamics of the UTP is similar to that of free external Rossby waves, with the beta effect (which leads to westward propagation) being the dominant term, whereas the eastward advection of relative vorticity is less important due to the weak mean zonal flow in the Alaska-Siberia sector. Most of the essential characteristics of the observed WTP deduced from the NCEP-NCAR reanalyses are well reproduced by the GCM. The realism with which this phenomenon can be simulated in a model environment offers considerable promise for using the GCM as a tool for studying the impact of WTP on intraseasonal atmospheric variability in extended model experiments, and for assessing the dependence of the locality and activity level of the WTP on various states of the ambient circulation. C1 Princeton Univ, NOAA, Geophys Fluid Dynam Lab, Princeton, NJ 08542 USA. RP Lau, NC (reprint author), Princeton Univ, NOAA, Geophys Fluid Dynam Lab, POB 308, Princeton, NJ 08542 USA. NR 44 TC 17 Z9 17 U1 0 U2 2 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0027-0644 J9 MON WEATHER REV JI Mon. Weather Rev. PD OCT PY 1999 VL 127 IS 10 BP 2324 EP 2345 DI 10.1175/1520-0493(1999)127<2324:OAGSWP>2.0.CO;2 PG 22 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 243PT UT WOS:000083007000007 ER PT J AU Yang, Y Navon, IM Todling, R Yang, WY AF Yang, Y Navon, IM Todling, R Yang, WY TI Sensitivity to large-scale environmental fields of the relaxed Arakawa-Schubert parameterization in the NASA GEOS-1 GCM SO MONTHLY WEATHER REVIEW LA English DT Article ID NON-LINEAR SYSTEMS; ADJOINT SENSITIVITY; ASSIMILATION; MODEL AB An adjoint sensitivity analysis of the relaxed Arakawa-Schubert scheme in the National Aeronautics and Space Administration GEOS-1 GCM with respect to perturbations in large-scale environmental fields was conducted. The response functions were defined as measures of the strength of convective cloud precipitation, the cloud-induced heating and drying (moistening) in both the instantaneous and time-integrated sense. The roles of different variables in producing variations on the response functions were evaluated and the most sensitive vertical levels of the perturbations were identified with the gradient provided by the adjoint model. It was found that the potential temperature perturbations had significant impact on ail the response functionals analyzed, especially on the convective precipitation. The perturbations at subcloud layers and at midtroposphere from 500 to 600 hPa were found to be the most influential. The impact from the moisture fields was most significant on cloud heating and drying effects and the strongest influence came from the subcloud layers. The moisture perturbations at midtroposphere also significantly influenced the cloud drying (moistening) effect. On the other hand, the cloud-induced heating and drying at levels between 400 and 600 hPa felt the strongest impact from perturbations in large-scale fields. The influence of the perturbations in the wind field was weaker but still provided reasonable sensitivity patterns. The time-integrated and instantaneous sensitivities for the same response differ only in magnitude but not in the general distributions. The impact of large-scale condensation and reevaporation on the sensitivity was also evaluated. Their effect was significant at the midtropospheric level and they enhanced the model sensitivity to perturbations in temperature and moisture fields. The sensitivity analysis results obtained indicated that accurate gridscale vertical profile of temperature and moisture, especially at subcloud layers and midtroposphere between 500 and 600 hPa were essential for the accurate evaluation of the cumulus cloud effects. The implications of the results of this work for variational data assimilation were also discussed. C1 Florida State Univ, Supercomp Computat Res Inst, Dept Math, Tallahassee, FL 32306 USA. NASA, DAO, Greenbelt, MD USA. Gen Sci Corp, Greenbelt, MD USA. NCEP, Environm Modeling Ctr, Camp Springs, MD USA. UCAR, Camp Springs, MD USA. RP Navon, IM (reprint author), Florida State Univ, Supercomp Computat Res Inst, Dept Math, Tallahassee, FL 32306 USA. RI Navon, Ionel/A-5173-2008 OI Navon, Ionel/0000-0001-7830-7094 NR 19 TC 3 Z9 3 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0027-0644 J9 MON WEATHER REV JI Mon. Weather Rev. PD OCT PY 1999 VL 127 IS 10 BP 2359 EP 2378 DI 10.1175/1520-0493(1999)127<2359:STLSEF>2.0.CO;2 PG 20 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 243PT UT WOS:000083007000009 ER PT J AU Lawrence, MB AF Lawrence, MB TI Eastern North Pacific hurricane season of 1997 SO MONTHLY WEATHER REVIEW LA English DT Article AB The hurricane season of the eastern North Pacific basin is summarized and individual tropical cyclones are described. The number of tropical cyclones was near normal. Hurricane Pauline's rainfall flooding killed more than 200 people in the Acapulco, Mexico, area. Linda became the strongest hurricane on record in this basin with 160-kt 1-min winds. C1 Natl Weather Serv, Trop Predict Ctr, NOAA, Miami, FL 33165 USA. RP Lawrence, MB (reprint author), Natl Weather Serv, Trop Predict Ctr, NOAA, 11691 SW 17 St, Miami, FL 33165 USA. NR 3 TC 14 Z9 14 U1 1 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0027-0644 J9 MON WEATHER REV JI Mon. Weather Rev. PD OCT PY 1999 VL 127 IS 10 BP 2440 EP 2454 DI 10.1175/1520-0493(1999)127<2440:ENPHSO>2.0.CO;2 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 243PT UT WOS:000083007000014 ER PT J AU Wang, JH Rossow, WB Uttal, T Rozendaal, M AF Wang, JH Rossow, WB Uttal, T Rozendaal, M TI Variability of cloud vertical structure during ASTEX observed from a combination of rawinsonde, radar, ceilometer, and satellite SO MONTHLY WEATHER REVIEW LA English DT Article ID UPPER-AIR OBSERVATIONS; MARINE STRATOCUMULUS; LIQUID WATER; FIRE-II; ALBEDO; LAYER; PHYSICS; SURFACE; ISLAND AB The macroscale cloud vertical structure (CVS), including cloud-base and -top heights and layer thickness, and characteristics of multilayered clouds, is studied at Porto Santo Island during the Atlantic Stratocumulus Transition Experiment (ASTEX) by using rawinsonde, radar, ceilometer, and satellite data. The comparisons of CVS parameters obtained from four different approaches show that 1) by using the method developed by Wang and Rossow rawinsonde observations (raob's) can sample all low clouds and determine their boundaries accurately, but oversample low clouds by about 10%, mistaking clear moist layers for clouds; 2) cloud-base heights less than 200 m in the radar data are ambiguous, but can be replaced by the values measured by ceilometer; and 3) the practical limit on the accuracy of marine boundary layer cloud-top heights retrieved from satellites appears to be about 150-300 m mainly due to errors in specifying the atmospheric temperature and humidity in the inversion layer above the cloud. The vertical distribution of clouds at Porto Santo during ASTEX is dominated by low clouds below 3 km, a cloud-free Layer between 3 and 4 km, and similar to 20% high clouds with a peak occurrence around 7-8 km. tow clouds have mean base and top heights of 1.0 km and 1.4 km, respectively, and occur as single layers 90% of the time. For double-layered low clouds, the tops of the uppermost layers and the bases of the lowermost layers have similar distributions as those of single-layered clouds. The temporal variations of low clouds during ASTEX are apparently dominated by advecting mesoscale (20-200 km) horizontal variations. Coherent time variations are predominately synoptic (timescale 4.5-6.8 days) and diurnal variability. On the diurnal timescale, all cloud properties show maxims in the early morning (around 0530 LST) decreasing to minima in the late afternoon. Diurnal variations appear to be altered when high clouds are present above low clouds. The general characteristics of CVS in three ASTEX and the First ISCCP Regional Experiment (FIRE87) regions derived from a 20-yr rawinsonde dataset are also presented. The results suggest that CVS characteristics obtained from data collected at Porto Santo during ASTEX (June 1992) are not representative of other marine stratiform cloud regions. C1 Univ Colorado, Program Atmospher & Ocean Sci, Boulder, CO 80309 USA. NASA, Goddard Inst Space Studies, New York, NY 10025 USA. NOAA, ERL, Environm Technol Lab, Boulder, CO 80303 USA. Columbia Univ, Dept Earth & Environm Sci, New York, NY USA. RP Natl Ctr Atmospher Res, SSSF, POB 3000, Boulder, CO 80307 USA. EM junhong@ucar.edu RI Rossow, William/F-3138-2015 NR 36 TC 51 Z9 54 U1 0 U2 6 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0027-0644 EI 1520-0493 J9 MON WEATHER REV JI Mon. Weather Rev. PD OCT PY 1999 VL 127 IS 10 BP 2484 EP 2502 DI 10.1175/1520-0493(1999)127<2484:VOCVSD>2.0.CO;2 PG 19 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 243PT UT WOS:000083007000017 ER PT J AU Klein, SA Jakob, C AF Klein, SA Jakob, C TI Validation and sensitivities of frontal clouds simulated by the ECMWF model SO MONTHLY WEATHER REVIEW LA English DT Article ID CIRCULATION SYSTEMS; SATELLITE; ISCCP; PARAMETERIZATION; MIDLATITUDE; CLIMATE; SCHEME AB Clouds simulated by the European Centre for Medium-Range Weather Forecasts (ECMWF) model are composited to derive the typical organization of clouds surrounding a midlatitude baroclinic system. Comparison of this composite of about 200 cyclones with that based on satellite data reveals that the ECMWF model quite accurately simulates the general positioning of clouds relative to a low pressure center. However, the optical depths of the model's high/low clouds are too small/large relative to the satellite observations, and the model lacks the midlevel topped clouds observed to the west of the surface cold front. Sensitivity studies with the ECMWF model reveal that the error in high-cloud optical depths is more sensitive to the assumptions applied to the ice microphysics than to the inclusion of cloud advection or a change of horizontal resolution from 0.5625 degrees to 1.69 degrees lat. This reflects the fact that in the ECMWF model gravitational settling is the most rapid process controlling the abundance of ice in the high clouds of midlatitude cyclones. These results underscore the need for careful evaluation of the parameterizations of microphysics and radiative properties applied to ice in large-state models. C1 Princeton Univ, NOAA, Geophys Fluid Dynam Lab, Princeton, NJ 08542 USA. European Ctr Medium Range Weather Forecasts, Reading RG2 9AX, Berks, England. RP Klein, SA (reprint author), Princeton Univ, NOAA, Geophys Fluid Dynam Lab, Forrestal Campus,US Route 1,POB 308, Princeton, NJ 08542 USA. RI Klein, Stephen/H-4337-2016; Jakob, Christian/A-1082-2010 OI Klein, Stephen/0000-0002-5476-858X; Jakob, Christian/0000-0002-5012-3207 NR 30 TC 232 Z9 238 U1 0 U2 10 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0027-0644 J9 MON WEATHER REV JI Mon. Weather Rev. PD OCT PY 1999 VL 127 IS 10 BP 2514 EP 2531 DI 10.1175/1520-0493(1999)127<2514:VASOFC>2.0.CO;2 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 243PT UT WOS:000083007000019 ER PT J AU Shaw, JA AF Shaw, JA TI Modeling infrared lunar radiance SO OPTICAL ENGINEERING LA English DT Article DE radiative transfer; infrared; radiometry; atmospheric optics; remote sensing; backgrounds ID THERMAL EMISSION; MOON; SPECTRA C1 NOAA, Environm Technol Lab, Boulder, CO 80303 USA. RP Shaw, JA (reprint author), NOAA, Environm Technol Lab, 325 Broadway, Boulder, CO 80303 USA. NR 13 TC 10 Z9 10 U1 0 U2 2 PU SPIE-INT SOCIETY OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, BELLINGHAM, WA 98225 USA SN 0091-3286 J9 OPT ENG JI Opt. Eng. PD OCT PY 1999 VL 38 IS 10 BP 1763 EP 1764 DI 10.1117/1.602250 PG 2 WC Optics SC Optics GA 243YG UT WOS:000083024600023 ER PT J AU Toggweiler, JR AF Toggweiler, JR TI Variation of atmospheric CO2 by ventilation of the ocean's deepest water SO PALEOCEANOGRAPHY LA English DT Article ID LAST GLACIAL MAXIMUM; SOUTHERN-OCEAN; ICE-CORE; THERMOHALINE CIRCULATION; HIGH-LATITUDE; INDIAN-OCEAN; CARBON; PALEOCHEMISTRY; DISTRIBUTIONS; INTERMEDIATE AB A new box model for glacial-interglacial changes in atmospheric CO2 produces lower levels of atmospheric CO2 without changes in biological production or nutrient chemistry. The model treats the boundary between middepth water and deep water as a chemical divide that separates low-CO2 water above from high-CO2 water below. Atmospheric CO2 is reduced 21 ppm by reduced ventilation of the deep water below the divide. A further reduction of 36 ppm is due to CaCO3 compensation in response to lower CO3= below the divide. Colder surface temperatures account for an additional 23 ppm of CO2 reduction. The new mechanism leaves the glacial atmosphere lighter in delta(13)C than in preindustrial time, as seen in ice cores and fossil plant material. Bottom water below the divide becomes strongly depleted in delta(13)C without st change in nutrient concentrations. C1 NOAA, Geophys Fluid Dynam Lab, Princeton, NJ 08542 USA. RP Toggweiler, JR (reprint author), NOAA, Geophys Fluid Dynam Lab, POB 308, Princeton, NJ 08542 USA. NR 59 TC 211 Z9 214 U1 6 U2 40 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0883-8305 J9 PALEOCEANOGRAPHY JI Paleoceanography PD OCT PY 1999 VL 14 IS 5 BP 571 EP 588 DI 10.1029/1999PA900033 PG 18 WC Geosciences, Multidisciplinary; Oceanography; Paleontology SC Geology; Oceanography; Paleontology GA 240MF UT WOS:000082829200002 ER PT J AU Kotob, SI McLaughlin, SM Van Berkum, P Faisal, M AF Kotob, SI McLaughlin, SM Van Berkum, P Faisal, M TI Discrimination between two Perkinsus spp. isolated from the softshell clam, Mya arenaria, by sequence analysis of two internal transcribed spacer regions and the 5 center dot 8S ribosomal RNA gene SO PARASITOLOGY LA English DT Article DE polymerase chain reaction; phylogenetic relationships; ribosomal RNA loci ID SCALLOPS ARGOPECTEN-IRRADIANS; N-SP APICOMPLEXA; CRYPTOSPORIDIUM-PARVUM; PARASITE; MARINUS; DNA; IDENTIFICATION; INFECTION; PROTISTA AB The internal transcribed spacer (ITS-1 and ITS-2) regions and the 5.8S ribosomal RNA gene of 2 Perkinsus spp. (G117 and H49) originating from the softshell clam, Mya arenaria, of the Chesapeake Bay were cloned and sequenced to obtain evidence for their genetic divergence. A high level of heterogeneity in both regions, probably resulting from deletions, insertions, and base substitutions, was evident from alignments of the sequences of the 2 isolates with published sequences of other Perkinsus spp. The isolate G117 and other Perkinsus spp. were highly divergent (13-26 % and 19-20 % sequence divergence in ITS-1 and ITS-2, respectively). These regions in the isolate H49 and Perkinsus marinus were similar (99.07 % and 99 % for ITS-1 and ITS-2, respectively). Evidence obtained from a phylogenetic analysis using the aligned sequences suggests that G117 and H49 belong to 2 distinct species of Perkins rls. The isolate G117 possibly belongs to an as yet undescribed species of Perkinsus, and H49 belongs to the species P. marinus. The conclusions drawn from the genetic analysis of H49 and G117 are supported by previously reported morphological characteristics (McLaughlin & Faisal, 1998b). Isolates H49 and G117 originated from the same molluscan species demonstrating that at least 2 different species of Perkinsus call co-exist in 1 host. C1 Coll William & Mary, Virginia Inst Marine Sci, Dept Environm Sci, Gloucester Point, VA 23062 USA. Natl Marine Fisheries Serv, Cooperat Oxford Lab, Oxford, MD 21654 USA. USDA, Beltsville, MD 20705 USA. RP Kotob, SI (reprint author), Coll William & Mary, Virginia Inst Marine Sci, Dept Environm Sci, Gloucester Point, VA 23062 USA. NR 31 TC 29 Z9 29 U1 1 U2 1 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 40 WEST 20TH STREET, NEW YORK, NY 10011-4211 USA SN 0031-1820 J9 PARASITOLOGY JI Parasitology PD OCT PY 1999 VL 119 BP 363 EP 368 DI 10.1017/S0031182099004801 PN 4 PG 6 WC Parasitology SC Parasitology GA 247FM UT WOS:000083210500006 PM 10581614 ER PT J AU Pedersen, HB Djuric, N Jensen, MJ Kella, D Safvan, CP Schmidt, HT Vejby-Christensen, L Andersen, LH AF Pedersen, HB Djuric, N Jensen, MJ Kella, D Safvan, CP Schmidt, HT Vejby-Christensen, L Andersen, LH TI Electron collisions with diatomic anions SO PHYSICAL REVIEW A LA English DT Review ID QUADRATIC CONFIGURATION-INTERACTION; CHARGED NEGATIVE-IONS; DISSOCIATIVE-RECOMBINATION; IMPACT DETACHMENT; GAS-PHASE; CROSS-SECTIONS; BONDING TRENDS; ABINITIO CALCULATIONS; RESONANCES; STATE AB Electron collisions with negative ions (B-2(-), C-2(-), O-2(-), BN-, and OH) have been performed in a merged-beams experiment at the heavy-ion storage ring ASTRID (Aarhus Storage Ring, Denmark). Absolute cross sections for detachment (e(-) + AB(-)-->AB(0) + 2e(-)) and detachment plus dissociation (e(-) + AB(-)-->A(0) + B-0 +2e(-)) are reported for energies below 40 eV. For the homonuclear ions, X-2(-) (X = B, C, O), cross sections are also presented for dissociative reactions leading to an X- particle in the final state. The detachment process is dominant for all investigated systems. The detachment cross section is characterized by an effective threshold larger than the electron binding energy. The shapes of the detachment cross sections are similar for the studied anions pointing to a common nonresonant mechanism for detachment. Also, the cross section for detachment plus dissociation and pure dissociation show regularities pointing to a general nonresonant mechanism. Structures are observed in the detachment cross section of C-2(-) and BN- and in the dissociation cross section of B-2(-) and C-2(-). The structures are attributed to short-lived dianions (resonances) formed during the collision process. The results are supported by ab initio calculations, and it is inferred that electronic excitations are important in the resonant reactions. [S1050-2947(99)05109-4]. C1 Univ Aarhus, Inst Phys & Astron, DK-8000 Aarhus C, Denmark. Univ Colorado, JILA, Boulder, CO 80309 USA. Natl Inst Stand & Technol, Boulder, CO 80309 USA. Stockholm Univ, Dept Phys, S-10405 Stockholm, Sweden. RP Pedersen, HB (reprint author), Univ Aarhus, Inst Phys & Astron, DK-8000 Aarhus C, Denmark. RI Schmidt, Henning/H-6277-2016 NR 124 TC 50 Z9 50 U1 0 U2 11 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD OCT PY 1999 VL 60 IS 4 BP 2882 EP 2899 DI 10.1103/PhysRevA.60.2882 PG 18 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 247BP UT WOS:000083201000047 ER PT J AU Parks, HV Leone, SR AF Parks, HV Leone, SR TI Initial- and final-state alignment and orientation effects in Ca energy pooling SO PHYSICAL REVIEW A LA English DT Article ID ASSOCIATIVE IONIZATION; ORBITAL ALIGNMENT; ANGULAR-MOMENTUM; CROSS-SECTIONS; SODIUM ATOMS; COLLISIONS; POLARIZATION; DEPENDENCE; 4-VECTOR; DYNAMICS AB An experimental investigation is performed to determine the initial- and final-state alignment effects in the energy-pooling process Ca(4s4p P-3(1)) + Ca(4s4p P-3(1))-->Ca(4s4p P-1(1)) + Ca(4s(2)). This paper represents a type of four-vector correlation experiment, where two aligned atoms collide and the alignment of the final excited state is observed. The initial Ca(4s4p P-3(1)) state polarization is controlled with polarized lasers and magnetic fields, and the final-state alignment is partially resolved by observing the polarization of the fluorescence from the Ca(4s4p P-1(1))-->Ca(4s(2)) emission. The mathematics are developed in this paper to provide a full quantitative description of the four-vector alignment cross sections observed here. Relative values that describe 18 of the 39 total independent parameters are obtained, thus defining the results of this collision process at an unprecedented level of detail. The final-state Ca polarization is found to be only weakly dependent on the initial-state alignment, with final-state fluorescence predominately polarized along the relative velocity vector of the collision. [S1050-2947(99)00510-7]. C1 Univ Colorado, JILA, Boulder, CO 80309 USA. Natl Inst Stand & Technol, Boulder, CO 80309 USA. Univ Colorado, Dept Phys, Boulder, CO 80309 USA. RP Parks, HV (reprint author), Univ Colorado, JILA, Boulder, CO 80309 USA. NR 28 TC 4 Z9 4 U1 1 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD OCT PY 1999 VL 60 IS 4 BP 2944 EP 2958 DI 10.1103/PhysRevA.60.2944 PG 15 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 247BP UT WOS:000083201000053 ER PT J AU Khalifah, P Erwin, RW Lynn, JW Huang, Q Batlogg, B Cava, RJ AF Khalifah, P Erwin, RW Lynn, JW Huang, Q Batlogg, B Cava, RJ TI Magnetic and electronic characterization of quasi-one-dimensional La3RuO7 SO PHYSICAL REVIEW B LA English DT Article ID SPIN-PEIERLS COMPOUND; CRYSTAL-STRUCTURE; CHARGE-DENSITY; PEROVSKITE AB The electronic and magnetic properties of La3RuO7 have been investigated. Its structure consists of corner-sharing RuO6 octahedra arranged in one-dimensional chains with a Ru-O-Ru angle of 145 degrees. The magnetic susceptibility shows Curie-Weiss behavior at 50-400 K with theta = -14 K and an effective moment of 3.94 mu(beta)/Ru atom. At lower temperatures (20-50 K), short-range antiferromagnetic order is observed. Neutron diffraction and magnetic susceptibility data show that long-range antiferromagnetic order exists below 20 K. A spin-flop transition is observed at applied fields greater than 1 T and temperatures below 17 K. Band structure calculations predict anisotropic electronic behavior and show that the ground state should be antiferromagnetic. [S0163-1829(99)05737-9]. C1 Princeton Univ, Dept Chem, Princeton, NJ 08540 USA. Princeton Univ, Princeton Mat Inst, Princeton, NJ 08540 USA. NIST, Ctr Neutron Res, Gaithersburg, MD 20899 USA. Univ Maryland, Dept Mat & Nucl Engn, College Pk, MD 20742 USA. AT&T Bell Labs, Lucent Technol, Murray Hill, NJ 07974 USA. RP Khalifah, P (reprint author), Princeton Univ, Dept Chem, Princeton, NJ 08540 USA. NR 25 TC 45 Z9 45 U1 1 U2 17 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD OCT 1 PY 1999 VL 60 IS 13 BP 9573 EP 9578 DI 10.1103/PhysRevB.60.9573 PG 6 WC Physics, Condensed Matter SC Physics GA 244YW UT WOS:000083079200072 ER PT J AU Yamaura, K Huang, Q Erwin, RW Lynn, JW Cava, RJ AF Yamaura, K Huang, Q Erwin, RW Lynn, JW Cava, RJ TI Anomalous crystal-structure distortion at the antiferromagnetic transition in the layered cobalt oxide Sr2Y0.8Ca0.2Co2O6 SO PHYSICAL REVIEW B LA English DT Article ID SINGLE-CRYSTAL; TEMPERATURE; LACOO3; INVAR; SPIN AB The temperature-dependent crystal structure and magnetic structure of the layered Ruddlesden-Popper phase Sr2Y0.8Ca0.2Co2O6 are reported. The crystal structure is orthorhombic below 270 K [Immm; a = 3.84029(7) Angstrom, b = 3.80691(6) Angstrom, and c = 19.4980(3) Angstrom at 20 K], transformed from tetragonal [I4/mmm; a = 3.82765(6) Angstrom, and c = 19.5795(3) Angstrom at 295 K]. The crystal structure distortion is accompanied by an anomalous temperature dependence of the degree of buckling of the CoO2 plane and is correlated with the development of anisotropic antiferromagnetic ordering of magnetic moments [2.93(2)mu(B) per Co at 20 K]. [S0163-1829(99)09437-0]. C1 Princeton Univ, Dept Chem, Princeton, NJ 08540 USA. Princeton Univ, Princeton Mat Inst, Princeton, NJ 08540 USA. Natl Inst Stand & Technol, Ctr Neutron Res, Gaithersburg, MD 20899 USA. Univ Maryland, Dept Mat & Nucl Engn, College Pk, MD 20742 USA. RP Yamaura, K (reprint author), Princeton Univ, Dept Chem, Princeton, NJ 08540 USA. NR 22 TC 8 Z9 8 U1 0 U2 2 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD OCT 1 PY 1999 VL 60 IS 13 BP 9623 EP 9629 DI 10.1103/PhysRevB.60.9623 PG 7 WC Physics, Condensed Matter SC Physics GA 244YW UT WOS:000083079200079 ER PT J AU Lee, SH Majkrzak, CF Sinha, SK Stassis, C Kawano, H Lander, GH Brown, PJ Fong, HF Cheong, SW Matsushita, H Yamada, K Endoh, Y AF Lee, SH Majkrzak, CF Sinha, SK Stassis, C Kawano, H Lander, GH Brown, PJ Fong, HF Cheong, SW Matsushita, H Yamada, K Endoh, Y TI Search for orbital moments in underdoped cuprate metals SO PHYSICAL REVIEW B LA English DT Article ID NEUTRON POLARIMETRY; BI2SR2CACU2O8+DELTA AB Polarized neutron-diffraction experiments have been performed in search of the orbital magnetic moments recently predicted in a theory for the cuprate metals. Both La2-xSrxCuO4 [LSCO(x)] and YBa2Cu3O6+x [YBCO(x)] compounds were investigated. No definitive evidence for the existence of such a three-dimensionally ordered moment was found in any of these samples within experimental uncertainty, which was as low as 0.01 mu(B). We have also investigated the possibility that a magnetic rod exists parallel to the c axis in the case of two- or quasi-two-dimensional ordering in the (a,b) plane and have set an upper limit for the total moment to be 0.1 mu(B) in LSCO (x = 0.1). [S0163-1829(99)02938-0]. C1 Univ Maryland, College Pk, MD 20742 USA. Natl Inst Stand & Technol, Ctr Neutron Res, Gaithersburg, MD 20899 USA. Argonne Natl Lab, Adv Photon Source, Argonne, IL 60439 USA. Iowa State Univ, Dept Phys, Ames, IA 50011 USA. Iowa State Univ, Ames Lab, Ames, IA 50011 USA. RIKEN, Magnet Mat Lab, Wako, Saitama 35101, Japan. Commiss European Communities, Joint Res Ctr, D-76125 Karlsruhe, Germany. Inst Max Von Laue Paul Langevin, F-38042 Grenoble, France. Princeton Univ, Dept Phys, Princeton, NJ 08544 USA. AT&T Bell Labs, Lucent Technol, Murray Hill, NJ 07974 USA. Rutgers State Univ, Dept Phys & Astron, Piscataway, NJ 08854 USA. Tohoku Univ, Dept Phys, Sendai, Miyagi 98077, Japan. Kyoto Univ, Inst Chem Res, Uji, Kyoto 6110011, Japan. Tohoku Univ, Dept Phys, Sendai, Miyagi 980776, Japan. RP Lee, SH (reprint author), Univ Maryland, College Pk, MD 20742 USA. RI Yamada, Kazuyoshi/C-2728-2009; Kawano-Furukawa, Hazuki/M-7695-2016; Kawano-Furukawa, Hazuki/M-7646-2016 OI Kawano-Furukawa, Hazuki/0000-0003-4713-3727; Kawano-Furukawa, Hazuki/0000-0003-4713-3727 NR 11 TC 6 Z9 7 U1 0 U2 2 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD OCT 1 PY 1999 VL 60 IS 14 BP 10405 EP 10417 DI 10.1103/PhysRevB.60.10405 PG 13 WC Physics, Condensed Matter SC Physics GA 244VE UT WOS:000083070800072 ER PT J AU Berg, RF Moldover, MR Zimmerli, GA AF Berg, RF Moldover, MR Zimmerli, GA TI Frequency-dependent viscosity of xenon near the critical point SO PHYSICAL REVIEW E LA English DT Article ID CLASSICAL FLUID; CRITICAL EXPONENT; CARBON-DIOXIDE; LIQUID; TEMPERATURE; VISCOMETER; GRAVITY; MODEL AB We used a novel, overdamped oscillator aboard the Space-Shuttle to measure the viscosity eta of xenon near its critical density rho(c) and temperature T-c. In microgravity, useful data were obtained within 0.1 mK of T-c, corresponding to a reduced temperature t =(T- T-c)/T-c= 3 X 10(-7). Because they avoid the detrimental effects of gravity at temperatures two decades closer to T-c than the best ground measurements, the data directly reveal the expected power-law behavior eta proportional to t(-nu z eta). Here nu is the correlation length exponent, and our result for the viscosity exponent is z(eta)= 0.0690+/- 0.0006. (All uncertainties are one standard uncertainty.) Our value for z(eta) depends only weakly on the form of the viscosity crossover function, and it agrees with the value 0.067+/- 0.002 obtained from a recent two-loop perturbation expansion [H. Hao, R.A. Ferrell, and J.K. Bhattacharjee, (unpublished)]. The measurements spanned the frequency range 2 Hz less than or equal to f less than or equal to 12 Hz and revealed viscoelasticity when t less than or equal to 10(-5), further from T-c than predicted. The viscoelasticity's frequency dependence scales as Af tau, where tau is the fluctuation-decay time. The fitted value of the viscoelastic time-scale parameter A is 2.0+/-0.3 times the result of a one-loop perturbation calculation. Near T-c, the xenon's calculated time constant for thermal diffusion exceeded days. Nevertheless, the viscosity results were independent of the xenon's temperature history, indicating that the density was kept near rho(c) by judicious choices of the temperature versus time program. Deliberately bad choices led to large density :inhomogeneities. At t>10(-5), the xenon approached equilibrium much faster than expected, suggesting that convection driven by microgravity and by electric fields slowly stirred the sample. [S1063-651X(99)04210-5]. C1 Natl Inst Stand & Technol, Phys & Chem Properties Div, Gaithersburg, MD 20899 USA. NYMA Inc, Brook Pk, OH 44142 USA. RP Berg, RF (reprint author), Natl Inst Stand & Technol, Phys & Chem Properties Div, Gaithersburg, MD 20899 USA. RI Moldover, Michael/E-6384-2013 NR 47 TC 59 Z9 59 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1063-651X J9 PHYS REV E JI Phys. Rev. E PD OCT PY 1999 VL 60 IS 4 BP 4079 EP 4098 DI 10.1103/PhysRevE.60.4079 PN A PG 20 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA 250XD UT WOS:000083414800074 PM 11970244 ER PT J AU Wyslouzil, BE Wilemski, G Cheung, JL Strey, R Barker, J AF Wyslouzil, BE Wilemski, G Cheung, JL Strey, R Barker, J TI Doppler shift anisotropy in small angle neutron scattering SO PHYSICAL REVIEW E LA English DT Article AB The two-dimensional patterns in our small angle neutron scattering (SANS) experiments from rapidly moving aerosols are anisotropic. To test the kinematic theory of two-body scattering that describes the anisotropy, we conducted SANS experiments using a constant source of D2O aerosol with droplets moving at similar to 440 m/s, and varied the neutron velocity from 267 to 800 m/s. The theoretically predicted anisotropy of the laboratory scattering intensities agrees well with the experimental results. Based on an analysis of the scattering intensity in the Guinier region, we also determined the particle velocity. The results are in very good agreement with independent velocity estimates based on supersonic flow measurements. [S1063-651X(99)02310-7]. C1 Worcester Polytech Inst, Dept Chem Engn, Worcester, MA 01609 USA. Univ Missouri, Dept Phys, Rolla, MO 65409 USA. Univ Missouri, Cloud & Aerosol Sci Lab, Rolla, MO 65409 USA. Univ Cologne, Inst Phys Chem, D-50939 Cologne, Germany. Natl Inst Stand & Technol, Cold Neutron Res Facil, Gaithersburg, MD 20899 USA. RP Wyslouzil, BE (reprint author), Worcester Polytech Inst, Dept Chem Engn, Worcester, MA 01609 USA. RI Wyslouzil, Barbara/G-8219-2012 NR 6 TC 19 Z9 19 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1063-651X J9 PHYS REV E JI Phys. Rev. E PD OCT PY 1999 VL 60 IS 4 BP 4330 EP 4335 DI 10.1103/PhysRevE.60.4330 PN B PG 6 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA 250XE UT WOS:000083414900016 PM 11970286 ER PT J AU Tewari, S Schiemann, D Durian, DJ Knobler, CM Langer, SA Liu, AJ AF Tewari, S Schiemann, D Durian, DJ Knobler, CM Langer, SA Liu, AJ TI Statistics of shear-induced rearrangements in a two-dimensional model foam SO PHYSICAL REVIEW E LA English DT Article ID 2-DIMENSIONAL SOAP FROTH; COMPRESSED EMULSIONS; PLATEAU BORDERS; BUBBLE DYNAMICS; ELASTICITY; MECHANICS; BEHAVIOR; SCALE AB Under steady shear, a foam relaxes stress through intermittent rearrangements of bubbles accompanied by sudden drops in the stored elastic energy. We use a simple model of foam that incorporates both elasticity and dissipation to study the statistics of bubble rearrangements in terms of energy drops, the number of nearest neighbor changes, and the rate of neighbor-switching (T1) events. We do this for a two-dimensional system as a function of system size, shear rate, dissipation mechanism, and gas area fraction. We find that for dry foams, there is a well-defined quasistatic limit at low shear rates where localized rearrangements occur at a constant rate per unit strain, independent of both system size and dissipation mechanism. These results are in good qualitative agreement with experiments on two-dimensional and three-dimensional foams. In contrast, we find for progessively wetter foams that the event size distribution broadens into a power law that is cut off only by system size. This is consistent with criticality at the melting transition. [S1069-651X(99)06610-6]. C1 Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA 90095 USA. Univ Calif Los Angeles, Dept Chem & Biochem, Los Angeles, CA 90095 USA. NIST, Informat Technol Lab, Gaithersburg, MD 20899 USA. RP Tewari, S (reprint author), Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA 90095 USA. RI Durian, Douglas/D-7013-2012 OI Durian, Douglas/0000-0003-3240-2381 NR 22 TC 63 Z9 63 U1 0 U2 7 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1063-651X J9 PHYS REV E JI Phys. Rev. E PD OCT PY 1999 VL 60 IS 4 BP 4385 EP 4396 DI 10.1103/PhysRevE.60.4385 PN B PG 12 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA 250XE UT WOS:000083414900023 PM 11970293 ER PT J AU Liao, GD Xie, YL Ludwig, KF Bansil, R Gallagher, P AF Liao, GD Xie, YL Ludwig, KF Bansil, R Gallagher, P TI Small-angle x-ray scattering study of kinetics of spinodal decomposition in N-isopropylacrylamide gels SO PHYSICAL REVIEW E LA English DT Article ID VOLUME-PHASE-TRANSITION; NEUTRON-SCATTERING; POLYMER BLENDS; DYNAMICS; FLUCTUATIONS AB We present synchrotron-based time-resolved small-angle x-ray scattering (SAXS) measurements of spinodal decomposition in a covalently cross-linked N-isopropylacrylamide gel. The range of wave numbers examined is well beyond the position of the maximum in the structure factor S(q,t). The equilibrium structure factor is described by the sum of a Lorentzian and a Gaussian. Following a temperature jump into the two phase region, the scattered intensity increases with time and eventually saturates. For early times the linear Cahn-Hilliard-Cook (CHC) theory can be used to describe the time evolution of the scattered intensity. From this analysis we found that the growth rate R(q) is linearly dependent on q(2), in agreement with mean-field theoretical predictions. However the Onsager transport coefficient Lambda(q)similar to q(-4), which is stronger than the q dependence pre dieted by the mean-field theory. We found that the growth rate R(q)>0, even though the wave numbers q probed by SAXS are greater than root 2q(m) where q(m) is the position of the peak of S(q,t), also in agreement with the mean-field predictions for a deep quench. We have also examined the range of validity of the linear CHC theory, and found that its breakdown occurs earlier at higher wave numbers. At later times, a pinning of the structure was observed. The relaxation to a final, microphase-separated morphology is faster and occurs earlier at the highest wave numbers, which probe length scales comparable to the average distance between crosslinks. [S1063-651X(99)12910-6]. C1 Boston Univ, Ctr Polymer Studies, Boston, MA 02215 USA. Boston Univ, Dept Phys, Boston, MA 02215 USA. Xerox Corp, Rochester, NY USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Liao, GD (reprint author), Boston Univ, Ctr Polymer Studies, Boston, MA 02215 USA. NR 24 TC 13 Z9 13 U1 0 U2 7 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1063-651X J9 PHYS REV E JI Phys. Rev. E PD OCT PY 1999 VL 60 IS 4 BP 4473 EP 4481 DI 10.1103/PhysRevE.60.4473 PN B PG 9 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA 250XE UT WOS:000083414900032 PM 11970302 ER PT J AU Friedman, HL Johnson, RA Gusev, V Neimark, AV Buvel, D Salem, DR Parnas, RS AF Friedman, HL Johnson, RA Gusev, V Neimark, AV Buvel, D Salem, DR Parnas, RS TI Visualization and quantification of forced in-plane flow through deformed porous media SO POLYMER COMPOSITES LA English DT Article; Proceedings Paper CT American-Society-of-Composites 13th Annual Technical Conference on Composite Materials CY SEP 21-23, 1998 CL BALTIMORE, MARYLAND SP Amer Soc Composites ID PERMEABILITY AB Fluid flow in liquid molding processes and in other applications involving porous media is often characterized with a permeability tensor and modeled by d'Arcy's law. The permeability is a sensitive function of pore structure, which, in deformable materials, is influenced by compression and extension. The majority of previous permeability measurements on composite reinforcement fabrics did not account for deformations imposed on them by corners and curves in the mold. In the present study, transparent molds were designed with a single 90 degrees bend in which the gap between plates was held constant throughout the flow path. Thus, the effects of fabric curvature on permeability were investigated independently of the effects of fabric compression in the thickness direction, A new experimental system was developed to visualize and quantify fluid flow in fabrics mounted in transparent molds. The reported measurements were conducted with fluid flowing through a (vertical) flat region of fabric, around the 90 degrees curve, and then along a second (horizontal) flat region. Permeability was found to be reduced by the imposed curvature for a nonwoven polyester and three-dimensional woven glass fabric. We were able to quantify the effect of curvature on permeability for the former, but not for the latter because of an enduring, dominant nonlinear entrance resistance. For the glass, comparison of two now rates indicates that the faster flow is characterized by a two stage filling process, whereas, at the slower rate, the liquid front fills all pores at the same time. C1 TRI Princeton, Princeton, NJ 08542 USA. Natl Inst Stand & Technol, Div Polymers, Gaithersburg, MD 20899 USA. RP Friedman, HL (reprint author), TRI Princeton, Princeton, NJ 08542 USA. NR 14 TC 3 Z9 3 U1 2 U2 3 PU SOC PLASTICS ENG INC PI BROOKFIELD PA 14 FAIRFIELD DR, BROOKFIELD, CT 06804-0403 USA SN 0272-8397 J9 POLYM COMPOSITE JI Polym. Compos. PD OCT PY 1999 VL 20 IS 5 BP 613 EP 627 DI 10.1002/pc.10384 PG 15 WC Materials Science, Composites; Polymer Science SC Materials Science; Polymer Science GA 255BT UT WOS:000083650200001 ER PT J AU Gharavi, H Hanzo, L AF Gharavi, H Hanzo, L TI Special issue on video transmission for mobile multimedia applications SO PROCEEDINGS OF THE IEEE LA English DT Editorial Material C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Univ Southampton, Southampton SO17 1BJ, Hants, England. RP Gharavi, H (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RI Hanzo, Lajos/S-4875-2016 OI Hanzo, Lajos/0000-0002-2636-5214 NR 0 TC 2 Z9 2 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9219 J9 P IEEE JI Proc. IEEE PD OCT PY 1999 VL 87 IS 10 BP 1703 EP 1706 PG 4 WC Engineering, Electrical & Electronic SC Engineering GA 238HX UT WOS:000082705800001 ER PT J AU Gharavi, H Alamouti, SM AF Gharavi, H Alamouti, SM TI Multipriority video transmission for third-generation wireless communication systems SO PROCEEDINGS OF THE IEEE LA English DT Article DE channel coding; mobile communications; video coding and partitioning; wide-band code division multiple access (CDMA) AB This paper presents a robust dual-priority video partitioning method suitable for twin-class unequal protected video transmission over wireless channels. The partitioning is based on a separation of the variable-length (VL) coded discrete cosine transform (DCT) coefficients within each block. The scheme is suitable for constant bit-rare transmission (CBR), where the fraction of bits assigned to each of the two partitions can be adjusted according to the requirements of the unequal error-protection scheme employed. The distribution of the VL-coded (VLC) information between the two partitions is performed adaptively. Subsequently, the partitioning method was applied to the ITU-T H.263 coding standard. It was shown that, for the input video with quarter common intermediate Sor mar (QCIF) spatial resolution (or less), the partitioning overhead can be embedded in the 5-bit code word representing the group number (GN), thus avoiding transmission of additional bits. As a transport vehicle, we have considered one of the leading third generation cellular radio standards known as wide-band code division multiple access (W-CDMA). A dual-priority transmission system is then invoked on the W-CDMA system where the video data, after being broken into two streams, are unequally protected. We use a very simple error-correction coding scheme for illustration and then propose more sophisticated forms of unequal protection of the digitized video signals. We show that this strategy results in a significantly higher quality of the reconstructed video data when they ai-e transmitted over time-varying multipath fading channels. C1 US Dept Commerce, Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Cadence Design Syst Inc, San Jose, CA 95134 USA. RP Gharavi, H (reprint author), US Dept Commerce, Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NR 13 TC 30 Z9 30 U1 0 U2 6 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9219 J9 P IEEE JI Proc. IEEE PD OCT PY 1999 VL 87 IS 10 BP 1751 EP 1763 DI 10.1109/5.790635 PG 13 WC Engineering, Electrical & Electronic SC Engineering GA 238HX UT WOS:000082705800005 ER PT J AU Schultz, DM Doswell, CA AF Schultz, DM Doswell, CA TI Conceptual models of upper-level frontogenesis in south-westerly and north-westerly flow SO QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY LA English DT Article DE atmospheric dynamics; fronts; Shapiro effect ID AGEOSTROPHIC CIRCULATIONS; BAROCLINIC DISTURBANCES; UPPER-TROPOSPHERE; MESOSCALE MODELS; CYCLONE; CYCLOGENESIS; SYSTEMS; SCHEME; FRONT; SCALE AB The conceptual model proposed by Shapiro as it is applied to the evolution of an upper-level frontal zone within a baroclinic wave is reviewed and its limitations are investigated through previous literature and two case-studies presented in this paper. The early stages in the evolutions of these two cases are used to examine specific limitations of this conceptual model: (1) upper-level frontogenesis in south-westerly flow that evolves from a state of equivalent barotropy to a state of cold advection along the front, and (2) upper-level frontogenesis in northwesterly flow with along-front variation in the sign of the thermal advection, such that warm advection occurs upstream of cold advection in the thermal trough. Vector-frontogenesis diagnostics for the Lagrangian rate of change of the magnitude and direction of the horizontal potential-temperature gradient, including tilting due to vertical motion, are derived. These diagnostics are applied to the two cases to examine the maintenance of the potential-temperature gradient and the development of cold advection along each upper-level front. The upper-level front in south-westerly (north-westerly) flow was maintained primarily by deformation (tilting) frontogenesis, in agreement with previous research. The increasing cold advection along the upper-level front in both cases was related to an upstream vorticity maximum. For the case in south-westerly flow, the pre-existing vorticity maximum approached a downstream equivalent-barotropic upper-level front in a manner similar to an instant occlusion, resulting in cold advection along the length of the upper-level front. For the case in north-westerly flow, an intensifying vorticity maximum concentrated the cold advection in the base of the thermal trough, as warm advection developed upstream. These two cases are compared to upper-level fronts in previous literature and a climatology of upper-level fronts associated with landfalling cyclones over the eastern North Pacific Ocean. The results indicate that these two cases are typical of early evolutions of upper-level fronts that can occur in south-westerly and north-westerly flow. Therefore, a revised version of the Shapiro conceptual model is presented that represents more accurately the early evolutions exhibited in the present and previous studies. C1 NOAA, Natl Severe Storms Lab, Norman, OK 73069 USA. RP Schultz, DM (reprint author), NOAA, Natl Severe Storms Lab, 1313 Halley Circle, Norman, OK 73069 USA. RI Doswell III, Charles/E-7662-2010; Schultz, David M./A-3091-2010 OI Schultz, David M./0000-0003-1558-6975 NR 70 TC 22 Z9 22 U1 0 U2 2 PU ROYAL METEOROLOGICAL SOC PI READING PA 104 OXFORD ROAD, READING, BERKS, ENGLAND RG1 7LJ SN 0035-9009 J9 Q J ROY METEOR SOC JI Q. J. R. Meteorol. Soc. PD OCT PY 1999 VL 125 IS 559 BP 2535 EP 2562 PN A PG 28 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 246MT UT WOS:000083168100009 ER PT J AU Joly, A Browning, KA Bessemoulin, P Cammas, JP Caniaux, G Chalon, JP Clough, SA Dirks, R Emanuel, KA Eymard, L Gall, R Hewson, TD Hildebrand, PH Jorgensen, D Lalaurette, F Langland, RH Lemaitre, Y Mascart, P Moore, JA Persson, POG Roux, F Shapiro, MA Snyder, C Toth, Z Wakimoto, RM AF Joly, A Browning, KA Bessemoulin, P Cammas, JP Caniaux, G Chalon, JP Clough, SA Dirks, R Emanuel, KA Eymard, L Gall, R Hewson, TD Hildebrand, PH Jorgensen, D Lalaurette, F Langland, RH Lemaitre, Y Mascart, P Moore, JA Persson, POG Roux, F Shapiro, MA Snyder, C Toth, Z Wakimoto, RM TI Overview of the field phase of the Fronts and Atlantic Storm-Track EXperiment (FASTEX) project SO QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY LA English DT Article DE cyclogenesis; field experiment; mesoscale observations; predictability ID FREQUENCY VARIABILITY; WAVES; CYCLOGENESIS; OBJECTIVES; STABILITY; CYCLONES; SYSTEMS; CLOUDS; PLANS AB The field phase of the Fronts and Atlantic Storm-Track EXperiment (FASTEX) project took place between 5 January and 27 February 1997 with the deployment of a unique set of observing facilities across the North Atlantic. The major objective was to document the life cycle of a representative set of mid-latitude cyclones. Other objectives were to rest the practical feasibility of 'adaptive' observations with a view to improving the prediction of these same cyclones and to document the internal structure of the associated cloud systems using combined airborne Doppler radars and dropsondes. Another goal of FASTEX was to measure air-sea exchange parameters under conditions of strong winds with high seas. These objectives were successfully achieved. Intensive Observation Periods were conducted on 19 occasions. High-resolution vertical profiles through the same cyclones at three different stages of their life cycle have been obtained on more than 10 occasions. The calculation of critical areas where further observations were needed to limit the growth of forecast error, was undertaken using different techniques, and flights were planned and executed in these areas in time to achieve this. Combined dropsonde and Doppler radar observations of cloud systems are available for 10 cases. A unique air-sea turbulent exchange dataset has been obtained. C1 Meteo France, CNRM, GMME, RECYF, F-31057 Toulouse 1, France. Joint Ctr Mesoscale Meteorol, Reading, Berks, England. CNRS, Lab Aerol, F-75700 Paris, France. UK Meteorol Off, Bracknell, Berks, England. Univ Corp Atmospher Res, Boulder, CO 80303 USA. MIT, Cambridge, MA 02139 USA. CNRS, Ctr Etud Environm Terrestre & Planetaires, F-75700 Paris, France. Natl Ctr Atmospher Res, Boulder, CO 80307 USA. Natl Ocean & Atmospher Adm, Silver Spring, MD 20910 USA. USN, Res Lab, Washington, DC 20375 USA. Univ Calif Los Angeles, Los Angeles, CA 90024 USA. RP Joly, A (reprint author), Meteo France, CNRM, GMME, RECYF, 42 Av Coriolis, F-31057 Toulouse 1, France. RI Toth, Zoltan/I-6624-2015 OI Toth, Zoltan/0000-0002-9635-9194 NR 54 TC 83 Z9 83 U1 1 U2 5 PU ROYAL METEOROLOGICAL SOC PI READING PA 104 OXFORD ROAD, READING, BERKS, ENGLAND RG1 7LJ SN 0035-9009 J9 Q J ROY METEOR SOC JI Q. J. R. Meteorol. Soc. PD OCT PY 1999 VL 125 IS 561 BP 3131 EP 3163 DI 10.1256/smsqj.56101 PN C PG 33 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 285LB UT WOS:000085389600002 ER PT J AU Szunyogh, I Toth, Z Emanuel, KA Bishop, CH Snyder, C Morss, RE Woolen, J Marchok, T AF Szunyogh, I Toth, Z Emanuel, KA Bishop, CH Snyder, C Morss, RE Woolen, J Marchok, T TI Ensemble-based targeting experiments during FASTEX: The effect of dropsonde data from the Lear jet SO QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY LA English DT Article DE Ensemble Transform (ET) technique; Fronts and Atlantic Storm-Track EXperiment (FASTEX); targeted observations ID ANALYSIS SYSTEM; ADAPTIVE OBSERVATIONS; SINGULAR VECTORS; SENSITIVITY; NCEP AB In this study we evaluate the performance of the Ensemble Transform (ET) technique, which is one of several targeting methods used in real time during the Fronts and Atlantic Storm-Track EXperiment (FASTEX). 'Targeted' observations were taken adaptively in those upstream areas identified in real time as most relevant for improving the initial conditions for forecasts of synoptic-scale storms developing downstream. The upstream areas were identified as regions where the effect of extra observations at a future analysis time could produce the largest decrease in the largest likely forecast error at a preselected later verification time at a given downstream location. The ET technique selects these observational areas out of a large number of possible deployment locations of observational resources via a linear transformation of an ensemble of forecasts. The analysis and forecast effects of special targeted observations associated with seven Intensive Observing Periods (IOPs) during FASTEX were investigated. The most important result of the present study is that the ET technique, based on the National Centers for Environmental Prediction (NCEP) operational global ensemble, was able to identify upstream areas that had significant contribution to the quality of selected future downstream forecast features. Moreover, the technique could reliably distinguish between the areas of greatest contribution. Through the overall impact of the targeted data on forecast quality is positive, there were cases when the extra data;degraded the forecasts. Our analysis indicates that large amplification of ensemble perturbations from the targeted area into the verification area is a good indicator of potential forecast improvement. C1 Nalt Ctr Environm Predict, EMC, WWB, Camp Springs, MD 20746 USA. Natl Ctr Environm Predict, Gen Sci Corp, Camp Springs, MD USA. MIT, Cambridge, MA 02139 USA. Penn State Univ, University Pk, PA 16802 USA. Natl Ctr Atmospher Res, Boulder, CO 80307 USA. RP Szunyogh, I (reprint author), Nalt Ctr Environm Predict, EMC, WWB, 5200 Auth Rd,Room 207, Camp Springs, MD 20746 USA. RI Szunyogh, Istvan/G-9248-2012; Toth, Zoltan/I-6624-2015 OI Toth, Zoltan/0000-0002-9635-9194 NR 41 TC 47 Z9 49 U1 0 U2 2 PU ROYAL METEOROLOGICAL SOC PI READING PA 104 OXFORD ROAD, READING, BERKS, ENGLAND RG1 7LJ SN 0035-9009 J9 Q J ROY METEOR SOC JI Q. J. R. Meteorol. Soc. PD OCT PY 1999 VL 125 IS 561 BP 3189 EP 3217 DI 10.1256/smsqj.56103 PN C PG 29 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 285LB UT WOS:000085389600004 ER PT J AU Langland, RH Gelaro, R Rohaly, GD Shapiro, MA AF Langland, RH Gelaro, R Rohaly, GD Shapiro, MA TI Targeted observations in FASTEX: Adjoint-based targeting procedures and data impact experiments in IOP17 and IOP18 SO QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY LA English DT Article DE adjoint methods; analysis error; extratropical cyclones; predictability; targeted observations ID SINGULAR VECTORS; FORECAST ERRORS; ADAPTIVE OBSERVATIONS; SENSITIVITY ANALYSIS; INITIAL CONDITIONS; MODEL; CYCLONE AB The Fronts and Atlantic Storm-Track EXperiment (FASTEX) provided an opportunity for testing targeted-observing procedures in a real-time framework during January and February 1997. This study describes the use of singular vectors (SVs) for objective targeting during FASTEX, and the evaluation of the impact obtained from targeted dropsonde data, satellite wind data, and other observations on 1-2 day forecast skill in intensive observation periods (IOPs) 17 and 18. In IOP17, targeted dropsondes improve a 42 h forecast of L41 (Low 41; cyclones were numbered in sequence throughout FASTEX) in terms of sea-level pressure, but the forecast skill is degraded in the upper troposphere. It is suggested that the degraded forecast may be caused by an incomplete survey of the SV target area, that improved the analysis in one region, bur made the analysis less accurate in an adjacent part of the target area where no dropsonde data were provided. In a series of experiments, the best 42 h forecast of L41 is obtained by the addition of a few radiosonde profiles provided specially for FASTEX at off-times, that provide observational data in the most sensitive part of the SV target area. The analysis differences introduced by the radiosonde profiles are much smaller in magnitude than those from the dropsonde data, but have a larger forecast impact, because they occur in an area that has larger error growth rates in this forecast. In a series of experiments for IOP18, the best 24 h forecast of L44 is obtained using a combination of targeted-dropsonde data and satellite wind data. Both data types can also be used separately to improve this forecast. The assimilation of satellite wind data and ship-based soundings in areas of weak initial-condition sensitivity ('null' areas) is shown to have minimal impact on the forecast error. The target areas identified by SVs in these two IOPs occur in strongly baroclinic regions, tending to favour the right-entrance and left-exit regions of the upper-level jet, but with greatest sensitivity near 600 hPa. C1 USN, Res Lab, Marine Meteorol Div, Monterey, CA 93943 USA. NOAA, ETL, Boulder, CO USA. RP Langland, RH (reprint author), USN, Res Lab, Marine Meteorol Div, 7 Grace Hopper Ave, Monterey, CA 93943 USA. NR 28 TC 69 Z9 78 U1 0 U2 4 PU ROYAL METEOROLOGICAL SOC PI READING PA 104 OXFORD ROAD, READING, BERKS, ENGLAND RG1 7LJ SN 0035-9009 J9 Q J ROY METEOR SOC JI Q. J. R. Meteorol. Soc. PD OCT PY 1999 VL 125 IS 561 BP 3241 EP 3270 DI 10.1256/smsqj.56105 PN C PG 30 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 285LB UT WOS:000085389600006 ER PT J AU Pu, ZX Kalnay, E AF Pu, ZX Kalnay, E TI Targeting observations with the quasi-inverse linear and adjoint NCEP global models: Performance during FASTEX SO QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY LA English DT Article DE adjoint Fronts and Atlantic Storm-Track EXperiment (FASTEX); quasi-inverse linear; targeted observations ID INITIAL CONDITIONS; SINGULAR VECTORS; FORECAST ERRORS; SENSITIVITY AB This note gives a brief summary of the targeting results obtained with both adjoint and quasi-inverse linear NCEP global spectral models during the Fronts and Atlantic Storm-Track EXperiment (FASTEX). Questions concerning the feasibility of the methods and related issues about targeting observations are briefly discussed. C1 Univ Space Res Assoc, NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Natl Ctr Environm Predict, Camp Springs, MD USA. RP Pu, ZX (reprint author), Univ Space Res Assoc, NASA, Goddard Space Flight Ctr, Mail Code 912, Greenbelt, MD 20771 USA. RI Kalnay, Eugenia/F-4393-2010; OI Kalnay, Eugenia/0000-0002-9984-9906 NR 13 TC 32 Z9 40 U1 0 U2 2 PU ROYAL METEOROLOGICAL SOC PI READING PA 104 OXFORD ROAD, READING, BERKS, ENGLAND RG1 7LJ SN 0035-9009 J9 Q J ROY METEOR SOC JI Q. J. R. Meteorol. Soc. PD OCT PY 1999 VL 125 IS 561 BP 3329 EP 3337 DI 10.1256/smsqj.56108 PN C PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 285LB UT WOS:000085389600009 ER PT J AU Davis, C Low-Nam, S Shapiro, MA Zou, XL Krueger, AJ AF Davis, C Low-Nam, S Shapiro, MA Zou, XL Krueger, AJ TI Direct retrieval of wind from total ozone mapping spectrometer (TOMS) data: Examples from FASTEX SO QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY LA English DT Article DE potential-vorticity inversion; upper-tropospheric analysis ID POTENTIAL-VORTICITY; CLIMATOLOGY AB The quantitative relationship between ozone and potential vorticity, and hence balanced wind and temperature, is examined using observations collected for a one-month period by the total ozone mapping spectrometer (TOMS). Ozone data are compared with Ertel potential vorticity (PV) integrated vertically from 500 to 50 mb, obtained from the NCEP/NCAR (National Centers for Environmental Prediction/National Center for Atmospheric Research) reanalysis archive. By performing a simple time filtering we isolate synoptic-scale transients in the ozone and PV. We show that the previously reported high correlation between PV and ozone is actually variable from day to day. The correlation also shows strong latitudinal dependence, with essentially no correlation in the tropics and high correlation in middle latitudes. A method is introduced to derive a three-dimensional PV representation from ozone data and a background field taken from the reanalysis data. PV-inversion methods are then used to recover balanced winds and temperatures and geopotential heights which may be compared to the analysed fields. Results suggest that many of the upper-tropospheric synoptic-scale wind perturbations may be recovered from the ozone data. A systematic error in the retrieval method used here is the underestimation of the strength of upper-level ridges, corresponding to an excess of vertically integrated ozone compared with integrated PV. We discuss reasons for this difference. C1 Natl Ctr Atmospher Res, Mesoscale & Microscale Meteorol Div, Boulder, CO 80307 USA. NOAA, Boulder, CO USA. Florida State Univ, Tallahassee, FL 32306 USA. NASA, Goddard Space Flight Ctr, Huntsville, AL 35812 USA. RP Davis, C (reprint author), Natl Ctr Atmospher Res, Mesoscale & Microscale Meteorol Div, POB 3000, Boulder, CO 80307 USA. NR 23 TC 10 Z9 12 U1 0 U2 0 PU ROYAL METEOROLOGICAL SOC PI READING PA 104 OXFORD ROAD, READING, BERKS, ENGLAND RG1 7LJ SN 0035-9009 J9 Q J ROY METEOR SOC JI Q. J. R. Meteorol. Soc. PD OCT PY 1999 VL 125 IS 561 BP 3375 EP 3391 DI 10.1256/smsqj.56111 PN C PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 285LB UT WOS:000085389600012 ER PT J AU Friedel, RHW Reeves, G Belian, D Cayton, T Mouikis, C Korth, A Blake, B Fennell, J Selesnick, R Baker, D Onsager, T Kanekal, S AF Friedel, RHW Reeves, G Belian, D Cayton, T Mouikis, C Korth, A Blake, B Fennell, J Selesnick, R Baker, D Onsager, T Kanekal, S TI A multi-spacecraft synthesis of relativistic electrons in the inner magnetosphere using LANL, GOES, GPS, SAMPEX, HEO and POLAR SO RADIATION MEASUREMENTS LA English DT Article; Proceedings Paper CT Conference on Space Radiation Environment Modeling: New Phenomena and Approaches CY OCT 07-09, 1997 CL MOSCOW, RUSSIA SP Moscow State Univ, Skobeltsyn Inst Nucl Phys, Moscow State Univ, Russian Acad Sci, Russian Space Agcy, Russian Fdn Basic Res, COSPAR ID RADIATION BELT; PARTICLE; SOLAR AB One of the Brussels Radiation Belt Workshop recommendation was the establishment of a near-real-time data driven model of the inner magnetospheric energetic particle population (L < 8). Although the "ideal" missions and data sets for such a model do not exist at present, more spacecraft than ever before are currently sampling the inner magnetosphere. We attempt here in a case study of the 10 January, 1997 magnetic cloud event to construct such a model with the energetic electron data available from 5 geosynchronous and 6 elliptically orbiting satellites. We examine the constraints and difficulties of putting together a large number of datasets which are measured near-simultaneously at very different locations in the inner magnetosphere. First results indicate that we can achieve a time resolution of about 3 h for a given "snapshot" of the inner magnetosphere, and that large azimuthal asymmetries of the energetic electron population can be observed during large storms. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87544 USA. Max Planck Inst Aeron, Katlenburg Lindau, Germany. Aerospace Corp, El Segundo, CA 90245 USA. LASP, Boulder, CO USA. NOAA, SEC, Boulder, CO USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Friedel, RHW (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87544 USA. RI Friedel, Reiner/D-1410-2012; Reeves, Geoffrey/E-8101-2011 OI Friedel, Reiner/0000-0002-5228-0281; Reeves, Geoffrey/0000-0002-7985-8098 NR 15 TC 2 Z9 2 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1350-4487 J9 RADIAT MEAS JI Radiat. Meas. PD OCT PY 1999 VL 30 IS 5 BP 589 EP 597 DI 10.1016/S1350-4487(99)00230-9 PG 9 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 259MY UT WOS:000083898700011 ER PT J AU Chappas, WJ Devney, BG Olding, RP McLaughlin, WL AF Chappas, WJ Devney, BG Olding, RP McLaughlin, WL TI EB curing of maritime composite structures SO RADIATION PHYSICS AND CHEMISTRY LA English DT Article AB Electron beam (EB) curing can be used to manufacture composite material components at higher speeds and with greater production flexibility than conventional techniques. Because curing is not initiated until irradiation, timing restrictions associate with lay up and resin infusion can be relaxed, leading to reduced scrap and rework. Furthermore EB curing systems are generally "solventless", with fewer VOCs, and therefore more environmentally friendly. This work demonstrates the feasibility of the practical application of this technology in the boat building industry. Specifically, it is shown that electron beams can successfully penetrate complex boat structures fabricated with off-the-shelf marine resins. In this way, the practical use of low-cost tooling with EB curing systems is reinforced. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 DAMILIC Corp, Rockville, MD 20850 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP DAMILIC Corp, 14670 Southlawn Lane, Rockville, MD 20850 USA. EM walter.chappas@damilic.com NR 10 TC 6 Z9 10 U1 0 U2 4 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0969-806X J9 RADIAT PHYS CHEM JI Radiat. Phys. Chem. PD OCT PY 1999 VL 56 IS 4 BP 417 EP 427 DI 10.1016/S0969-806X(99)00335-7 PG 11 WC Chemistry, Physical; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical SC Chemistry; Nuclear Science & Technology; Physics GA 252WK UT WOS:000083525100006 ER PT J AU Alfassi, ZB Dhanasekaran, D Huie, RE Neta, P AF Alfassi, ZB Dhanasekaran, D Huie, RE Neta, P TI On the reactions of CO3 center dot- radicals with NOx radicals SO RADIATION PHYSICS AND CHEMISTRY LA English DT Article ID CARBON-DIOXIDE; PULSE-RADIOLYSIS; AQUEOUS-SOLUTION; RATE CONSTANTS; INORGANIC RADICALS; PEROXYNITRITE; ACID; OXIDATIONS; DECOMPOSITION; REACTIVITY AB The reactions of CO3.- radicals with NOx radicals were studied by pulse radiolysis of deoxygenated aqueous solutions containing carbonate and nitrate ions. The (OH)-O-. radicals react with carbonate to yield CO3.- and the e(aq)(-) reacts with nitrate to yield NO3.2-, which then converts into NO2.. This conversion has a rate constant of 4.6 x 10(4) s(-1) in alkaline solutions but is catalyzed by HCO3- (k = 2.8 x 10(7) L mol(-1) s(-1)). The CO3.- radicals react rapidly with both NO3.2- (k = 1.0 x 10(9) L mol(-1) s(-1)) and NO2. (k = 4.6 x 10(8) L mol(-1) s(-1)). The expected combination product was short lived and was not observed on the microsecond time scale and the possible peroxynitrite product was not detected following gamma-radiolysis. A similar study with solutions containing carbonate and nitrite shows that NO2.2- reacts with CO3.- faster than NO3.2- and NO reacts with CO3.- faster than NO3.2. (C) 1999 published by Elsevier Science Ltd. All rights reserved. C1 Natl Inst Stand & Technol, Phys & Chem Properties Div, Gaithersburg, MD 20899 USA. RP Neta, P (reprint author), Natl Inst Stand & Technol, Phys & Chem Properties Div, Gaithersburg, MD 20899 USA. RI Huie, Robert/A-5645-2010 NR 35 TC 19 Z9 19 U1 0 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0969-806X J9 RADIAT PHYS CHEM JI Radiat. Phys. Chem. PD OCT PY 1999 VL 56 IS 4 BP 475 EP 482 DI 10.1016/S0969-806X(99)00331-X PG 8 WC Chemistry, Physical; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical SC Chemistry; Nuclear Science & Technology; Physics GA 252WK UT WOS:000083525100011 ER PT J AU McLaughlin, WL Silverman, J Al-Sheikhly, M Chappas, WJ Liu, ZJ Miller, A Batsberg-Pedersen, W AF McLaughlin, WL Silverman, J Al-Sheikhly, M Chappas, WJ Liu, ZJ Miller, A Batsberg-Pedersen, W TI High-density polyethylene dosimetry by transvinylene FTIR analysis SO RADIATION PHYSICS AND CHEMISTRY LA English DT Article ID RADIATION AB The formation of transvinylene unsaturation, -CH=CH-, due to free-radical or cationic-initiated dehydrogenation by irradiation, is a basic reaction in polyethylene and is useful for dosimetry at high absorbed doses. The radiation-enhanced infrared absorption having a maximum at nu = 965 cm(-l) (lambda = 10.36 mu m) is stable in air and can be measured by Fourier-transform infrared (FTIR) spectrophotometry. The quantitative analysis is a useful means of product end-point dosimetry for radiation processing with gamma rays and electrons, where polyethylene is a component of the processed product. The transvinylene response in air to gamma radiation is linear with dose and has relatively low yield compared with the response to electrons, whereas the response in deaerated polyethylene samples is also linear, but is more sensitive, and has negligible dose-rate dependence in its response to gamma rays and electrons. The useful dose range of 0.053 cm thick high-density polyethylene film (rho = 0.961 g cm(-3); melt index = 0.8 dg min(-1)), for irradiations by (60)Co gamma radiation and 2.0 and 0.4 MeV electron beams in deaerated atmosphere (Na gas), is about 50-10(3) kGy for FTIR transvinylene spectrophotometric analysis. The measured product of linear molar extinction coefficient and radiation chemical yield for transvinylene formation in this case is 3.22 x 10(-6) m(2) J(-1), and G(-CH=CH-)= 0.116 mu mol J(-1) = 1.12 (100 eV)(-1). The estimated uncertainty for deriving these values by this method is about +/- 5% at 67% confidence level. Published by Elsevier Science Ltd. C1 Natl Inst Stand & Technol, Phys Lab, Ionizing Radiat Div, Gaithersburg, MD 20899 USA. Univ Maryland, Dept Mat & Nucl Engn, College Pk, MD 20742 USA. DAMILIC Corp, Rockville, MD 20850 USA. Univ Sci & Technol, Hefei, Anhui, Peoples R China. Riso Natl Lab, DK-4000 Roskilde, Denmark. RP McLaughlin, WL (reprint author), Natl Inst Stand & Technol, Phys Lab, Ionizing Radiat Div, Gaithersburg, MD 20899 USA. NR 36 TC 21 Z9 21 U1 0 U2 4 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0969-806X J9 RADIAT PHYS CHEM JI Radiat. Phys. Chem. PD OCT PY 1999 VL 56 IS 4 BP 503 EP 508 DI 10.1016/S0969-806X(99)00324-2 PG 6 WC Chemistry, Physical; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical SC Chemistry; Nuclear Science & Technology; Physics GA 252WK UT WOS:000083525100014 ER PT J AU Running, SW Baldocchi, DD Turner, DP Gower, ST Bakwin, PS Hibbard, KA AF Running, SW Baldocchi, DD Turner, DP Gower, ST Bakwin, PS Hibbard, KA TI A global terrestrial monitoring network integrating tower fluxes, flask sampling, ecosystem modeling and EOS satellite data SO REMOTE SENSING OF ENVIRONMENT LA English DT Article; Proceedings Paper CT International FLUXNET Meeting CY JUN 03-05, 1998 CL POLSON, MT SP U S Dept Energy, Nat Aeronautics & Space Adm Earth Sci Enterprise, Nat Oceanic & Atmospjeric Adm, Nat Sci Fdn, Int Geosphere-Biosphere Program, Global Climate Res Program ID NET PRIMARY PRODUCTION; ATMOSPHERIC CARBON-DIOXIDE; EDDY-CORRELATION; CLIMATE-CHANGE; WATER-VAPOR; SPATIAL-RESOLUTION; SEASONAL-VARIATION; FOREST; EXCHANGE; CO2 AB Acurrate monitoring of global seals changes in the terrestrial biosphere has become acutely important as the scope of human impacts on biological systems and atmospheric chemistry grows. For example, the Kyoto Protocol of 1997 signals some of the dramatic socioeconomic and political decisions that may lie ahead concerning CO(2) emissions and global carbon cycle impacts. These decisions will rely heavily on accurate measures of global biospheric changes (Schimel 1998; IGBP TCWG, 1998). An array of national and international programs have inaugurated global satellite observations, critical field measurements of carbon and water fluxes, and global model development for the purposes of beginning to monitor the biosphere. The detection by these programs of interannual variability of ecosystem fluxes and of longer term trends will permit early indication of fundamental biospheric changes which might otherwise go undetected until major biome conversion begins. This article describes a blueprint for more comprehensive coordination of the various flux measurement and modeling activities into a global terrestrial monitoring network that will have direct relevance to the political decision making of global change. (C) Elsevier Science Inc., 1999. C1 Univ Montana, Sch Forestry, Numer Terradynam Simulat Grp, Missoula, MT 59812 USA. Oak Ridge Natl Lab, ATDD, Oak Ridge, TN USA. Oregon State Univ, Dept Forest Sci, Corvallis, OR 97331 USA. Univ Wisconsin, Dept Forestry, Madison, WI 53706 USA. NOAA, Climate Monitoring & Diagnost Lab, Boulder, CO 80303 USA. Univ New Hampshire, Climate Change Res Ctr, Durham, NH 03824 USA. RP Running, SW (reprint author), Univ Montana, Sch Forestry, Numer Terradynam Simulat Grp, Missoula, MT 59812 USA. EM swr@ntsg.umt.edu RI Baldocchi, Dennis/A-1625-2009; Vuichard, Nicolas/A-6629-2011 OI Baldocchi, Dennis/0000-0003-3496-4919; NR 72 TC 391 Z9 422 U1 8 U2 65 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD OCT PY 1999 VL 70 IS 1 BP 108 EP 127 DI 10.1016/S0034-4257(99)00061-9 PG 20 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA 241LJ UT WOS:000082884500009 ER PT J AU Hawley, N Lee, CH AF Hawley, N Lee, CH TI Sediment resuspension and transport in Lake Michigan during the unstratified period SO SEDIMENTOLOGY LA English DT Article DE bottom currents; Lake Michigan; limnology; resuspension; sediment transport; surface waves ID BENTHIC NEPHELOID LAYER; GREAT-LAKES; CURRENTS; ONTARIO; EROSION; EVENTS AB Instrumented moorings were deployed during the winter of 1994-95 at three depths (28, 58 and 101 m) in southern Lake Michigan. Storms during the observation period were not unusually severe, so the processes observed are typical of those that occur during an average winter. Time series observations of water temperature, beam attenuation coefficient (a measure of water transparency) and current velocity show that local resuspension of bottom sediment occurred frequently after the breakdown of the thermocline. Resuspension was most frequent close to the shore but was also observed at the 58 m station, Local resuspension did not occur at the 101 m station, but advection to the site of material resuspended at shallower sites was observed. These observations do not support the hypothesis proposed by previous investigators that local resuspension at depths of 100 m or greater occurs during the unstratified period. It is more likely that fine-grained material resuspended by storm action in intermediate water depths (approximate to 30-60 m) is transported into the deeper parts of the lake by the general lake circulation. C1 NOAA, Great Lakes Environm Res Lab, Ann Arbor, MI 48105 USA. Cooperat Inst Limnol & Ecosyst Res, Ann Arbor, MI 48105 USA. RP Hawley, N (reprint author), NOAA, Great Lakes Environm Res Lab, 2205 Commonwealth Blvd, Ann Arbor, MI 48105 USA. EM hawley@glerl.noaa.gov NR 27 TC 21 Z9 22 U1 1 U2 4 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 0037-0746 J9 SEDIMENTOLOGY JI Sedimentology PD OCT PY 1999 VL 46 IS 5 BP 791 EP 805 DI 10.1046/j.1365-3091.1999.00251.x PG 15 WC Geology SC Geology GA 253AW UT WOS:000083535300002 ER PT J AU Atalla, RH VanderHart, DL AF Atalla, RH VanderHart, DL TI The role of solid state C-13 NMR spectroscopy in studies of the nature of native celluloses SO SOLID STATE NUCLEAR MAGNETIC RESONANCE LA English DT Article DE cellulose; native; carbon-13; NMR; solid state; structure; allomorphs; Raman; infrared; electron diffraction; review ID NUCLEAR-MAGNETIC-RESONANCE; HIGH-RESOLUTION; VALONIA CELLULOSE; CRYSTALLINE FORMS; HIGH-TEMPERATURES; TRANSFORMATION; MICROFIBRILS; SPECTRA; MACROPHYSA; ALKALINE AB Published spectroscopic observations pertaining to the crystal structure of native celluloses are reviewed for the purpose of defining our current level of understanding about crystalline polymorphism in these materials. Emphasis is placed on observations from solid state C-13 nuclear magnetic resonance (NMR), which first led to the postulate that most native, semicrystalline celluloses are composites of two crystalline allomorphs, labeled I-alpha and I-beta. Historical background is presented, highlighting the structural controversies which mainly arose because different native celluloses were used, each one representing a different mixture of allomorphs. Input from Raman, infrared (IR) and electron diffraction data is included in the discussion of our current understanding of polymorphism in native celluloses. Also noted is the input from more recently studied celluloses (e.g., Halocynthia) as well as from newer processes that convert the I-alpha to the I-beta form. On the basis of Raman and IR observations, it is argued that the I-alpha and I-beta allomorphs differ in hydrogen bonding patterns only and that backbone conformations are nearly identical. Also, the point is made that the absence of correlation field splittings in the Raman spectra calls into question (although it does not disprove) whether the normal two-chain-per-unit-cell, monoclinic I-beta allomorph really possesses two equivalent chains. Considerable discussion is devoted to the allomorphic composition of cellulose crystallites in higher plants. Published methods of NMR lineshape analysis for the higher plant celluloses are reviewed and critiqued, both from the point of view of lineshape theory and from the point of view of self-consistency of inferences that are based on lineshape analyses for different carbons (particularly C1 and C4). It is concluded that higher plant celluloses most likely possess a minor amount of the I-alpha allomorph where the I-alpha/I-beta ratio is probably less than 0.25. (C) 1999 Elsevier Science B.V. All rights reserved. C1 US Forest Serv, USDA, Forest Prod Lab, Madison, WI 53705 USA. NIST, Div Polymers, Gaithersburg, MD 20899 USA. RP Atalla, RH (reprint author), US Forest Serv, USDA, Forest Prod Lab, 1 Gifford Pinchot Dr, Madison, WI 53705 USA. NR 57 TC 196 Z9 202 U1 3 U2 88 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0926-2040 J9 SOLID STATE NUCL MAG JI Solid State Nucl. Magn. Reson. PD OCT PY 1999 VL 15 IS 1 BP 1 EP 19 DI 10.1016/S0926-2040(99)00042-9 PG 19 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical; Physics, Condensed Matter; Spectroscopy SC Chemistry; Physics; Spectroscopy GA 265AJ UT WOS:000084215900002 PM 10903080 ER PT J AU Winchester, MR Beck, U AF Winchester, MR Beck, U TI Availability of layered certified reference materials for industrial application of glow discharge spectrometric depth profiling SO SURFACE AND INTERFACE ANALYSIS LA English DT Article DE certified reference materials; depth profiling; glow discharge spectrometry; ISO ID OPTICAL-EMISSION SPECTROMETRY; VAPOR-DEPOSITION; HARD COATINGS; OXIDE SCALES; STEEL; SPECTROSCOPY; FILMS; GDOS; QUANTIFICATION; SURFACES AB Owing primarily to speed, low cost and ease of use relative to competing surface analysis techniques, glow discharge spectrometry (GDS) has become an economically important depth profiling method for certain niche industries in Europe and Japan. For the industrial application of this method, layered certified reference materials (CRMs) are needed to ensure accuracy, as well as comparability between individual users. A survey of existing CRMs has been conducted to evaluate the availability of layered CRMs with appropriate characteristics. No materials with the desirable characteristics necessary for efficient implementation were found. These results indicate a need for the production of new layered CRMs. The survey was conducted by an advisory group assembled as part of the activities of the Glow Discharge Spectrometry Subcommittee (ISO TC201/SC8) associated with the ISO Technical Committee on Surface Chemical Analysis (ISO TC201), Copyright (C) 1999 John Wiley & Sons, Ltd. C1 NIST, Chem Sci & Technol Lab, Div Analyt Chem, Gaithersburg, MD 20899 USA. Bundesanstalt Mat Prufung, D-12205 Berlin, Germany. RP Winchester, MR (reprint author), NIST, Chem Sci & Technol Lab, Div Analyt Chem, Gaithersburg, MD 20899 USA. RI Beck, Uwe/A-2457-2012 NR 48 TC 6 Z9 6 U1 0 U2 2 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX PO19 1UD, ENGLAND SN 0142-2421 J9 SURF INTERFACE ANAL JI Surf. Interface Anal. PD OCT PY 1999 VL 27 IS 10 BP 930 EP 935 PG 6 WC Chemistry, Physical SC Chemistry GA 248UK UT WOS:000083294000007 ER PT J AU Wittberg, TN Wang, PS AF Wittberg, TN Wang, PS TI XPS study of the dehydration of clay and kaolin powders SO SURFACE AND INTERFACE ANALYSIS LA English DT Article DE XPS; powder; Auger parameter; clay; kaolin ID AUGER AB X-ray photoelectron spectroscopy (XPS) was used to analyze samples of a commercial clay powder and a kaolin standard. Samples were analyzed both in the as-received condition and after heating to temperatures of greater than or equal to 750 degrees C, There was a loss of water during heating that corresponded to the transformation from a clay to an aluminosilicate, The XPS measurements showed that there was a decrease in the O/(Al+Si) ratio and a decrease of 0.2-0.3 eV in the aluminum Auger parameter value. The silicon Auger parameter value was unchanged after heating. Copyright (C) 1999 John Wiley & Sons, Ltd. C1 Univ Dayton, Res Inst, Dayton, OH 45469 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Wittberg, TN (reprint author), Univ Dayton, Res Inst, Dayton, OH 45469 USA. NR 9 TC 6 Z9 7 U1 0 U2 11 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX PO19 1UD, ENGLAND SN 0142-2421 J9 SURF INTERFACE ANAL JI Surf. Interface Anal. PD OCT PY 1999 VL 27 IS 10 BP 936 EP 940 DI 10.1002/(SICI)1096-9918(199910)27:10<936::AID-SIA656>3.0.CO;2-N PG 5 WC Chemistry, Physical SC Chemistry GA 248UK UT WOS:000083294000008 ER PT J AU Van Hove, MA Hermann, K Watson, PR Rumble, J AF Van Hove, MA Hermann, K Watson, PR Rumble, J TI Greatly improved surface structure database - SSD version 3 SO SURFACE REVIEW AND LETTERS LA English DT Article; Proceedings Paper CT 6th International Conference on the Structure of Surfaces (ICSOS-6) CY JUL 26-30, 1999 CL UNIV BRITISH COLUMBIA, VANCOUVER, CANADA SP Univ British Columbia HO UNIV BRITISH COLUMBIA AB SSD-3, the third version of the NIST Surface Structure Database, appeared in 1999 as a major update. A complete revision of the database and graphics software upgrades SSD to a Windows environment (MS Windows 95, 98 and NT). SSD-3 includes over 1100 structures published through the end of 1997. SSD is an interactive PC-based database of critically selected surface structures determined with a variety of experimental techniques. The data include not only atomic coordinates, bond lengths and bond angles, but also information about experimental preparation, measurement and analysis methods. The software provides advanced search and display facilities, as well as interactive three-dimensional color visualization and, analysis tools of great flexibility. In addition, the program can generate publication-quality color or gray-scale prints of any structure, with a host of user-selectable options (such as view angle, perspective, colors, ball and bond styles, and labels). C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Div Sci Mat, Berkeley, CA 94720 USA. Univ Calif Davis, Dept Phys, Davis, CA 95616 USA. Fritz Haber Inst, Abt Theorie, D-14195 Berlin, Germany. Oregon State Univ, Dept Chem, Corvallis, OR 97330 USA. Natl Inst Stand & Technol, Stand Reference Data Program, Gaithersburg, MD 20899 USA. RP Van Hove, MA (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, Div Sci Mat, Mailstop 66-200, Berkeley, CA 94720 USA. RI Van Hove, Michel/A-9862-2008 OI Van Hove, Michel/0000-0002-8898-6921 NR 3 TC 3 Z9 3 U1 0 U2 0 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA JOURNAL DEPT PO BOX 128 FARRER ROAD, SINGAPORE 912805, SINGAPORE SN 0218-625X J9 SURF REV LETT JI Surf. Rev. Lett. PD OCT PY 1999 VL 6 IS 5 BP 805 EP 811 PG 7 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA 300LQ UT WOS:000086254800033 ER PT J AU Wernli, H Shapiro, MA Schmidli, J AF Wernli, H Shapiro, MA Schmidli, J TI Upstream development in idealized baroclinic wave experiments SO TELLUS SERIES A-DYNAMIC METEOROLOGY AND OCEANOGRAPHY LA English DT Article; Proceedings Paper CT Rossby-100 Symposium CY JUN 08-12, 1998 CL STOCKHOLM, SWEDEN ID POTENTIAL VORTICITY; CYCLOGENESIS; CYCLONES; FRONTOGENESIS; DOWNSTREAM; FRONTS AB An idealized dry primitive equation model on the f-plane is used to study upstream (and downstream) baroclinic wave development. The simulations are initiated with localized finite amplitude and vertically evanescent perturbations, specified either as upper-level potential vorticity or surface potential temperature anomalies. The nonlinear evolution of these nonmodal perturbations leads to the generation of large-scale upper-level induced primary and downstream surface cyclones, and of distinctively smaller, shallow and more slowly intensifying upstream systems. It is shown that in particular the genesis and evolution of upstream cyclones is highly sensitive to the scale of the initial perturbation. Narrow upper-level troughs (or zonally confined surface temperature anomalies) are favorable for upstream development, whereas no or only weak upstream activity occurs with broad planetary-scale troughs (or zonally extended surface temperature anomalies) as initial perturbations. It is proposed that this sensitivity property of upstream development is qualitatively related to the dispersion characteristics of surface edge waves. The shortcomings of the present approach are discussed, and some consideration is given to the occurrence of upstream cyclogenesis in the real atmosphere, to the relationship with earlier concepts of secondary cyclogenesis, and to possible implications for the issue of predictability of extratropical weather systems. C1 ETH Honggerberg, Inst Atmospher Sci, CH-8093 Zurich, Switzerland. NOAA, Environm Technol Lab, Boulder, CO 80303 USA. RP Wernli, H (reprint author), ETH Honggerberg, Inst Atmospher Sci, CH-8093 Zurich, Switzerland. RI Schmidli, Juerg/G-9282-2012 OI Schmidli, Juerg/0000-0002-6322-6512 NR 24 TC 15 Z9 15 U1 0 U2 0 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0280-6495 J9 TELLUS A JI Tellus Ser. A-Dyn. Meteorol. Oceanol. PD OCT PY 1999 VL 51 IS 5 BP 574 EP 587 DI 10.1034/j.1600-0870.1999.00003.x PG 14 WC Meteorology & Atmospheric Sciences; Oceanography SC Meteorology & Atmospheric Sciences; Oceanography GA 254KD UT WOS:000083609700003 ER PT J AU Doyle, JD Shapiro, MA AF Doyle, JD Shapiro, MA TI Flow response to large-scale topography: the Greenland tip jet SO TELLUS SERIES A-DYNAMIC METEOROLOGY AND OCEANOGRAPHY LA English DT Article; Proceedings Paper CT Rossby-100 Symposium CY JUN 08-12, 1998 CL STOCKHOLM, SWEDEN ID PAST ISOLATED TOPOGRAPHY; MESOSCALE MOUNTAINS; AIR-FLOW; MODEL; SIMULATION; ATMOSPHERE; WAVES; RIDGE; WAKE AB Numerical model simulations of idealized and observed flows are used to investigate the dynamics of low-level jet streams that form in stratified flow downstream of the vertex of large elliptical barriers such as the southern tip of Greenland, hereafter referred to as "tip jets". The lip jet dynamics are governed by conservation of Bernouli function as parcels accelerate down the pressure gradient during orographic descent. In some circumstances, the Greenland tip jet is influenced by baroclinic effects such as differential horizontal (cross-stream) thermal advection and/or vertical shear. In contrast, in the barotropic situation upstream flow is diverted around and over the obstacle into laminar (Bernouli conservation) and turbulent (Bernouli deficit) regimes, respectively. In both situations, a downstream geostrophic balance is achieved, characterized by baroclinicity and vertical shear associated with the surface-based tip-jet front. The strength of the tip-jet is most sensitive to changes in the basic state dimensionless mountain height (Nh/U) and Rossby number, underscoring the importance of the orographic deflection of airstreams and Lagrangian accelerations on the slope. Enhanced surface-based forcing of the ocean circulation occurs in the region of the tip jet core through large air-sea energy exchange (upward surface-heal fluxes > 800 W m(-2)), and at the tip jet flank through localized surface stress forcing. C1 USN, Res Lab, Marine Meteorol Div, Monterey, CA 93943 USA. NOAA, Environm Technol Lab, Boulder, CO USA. Natl Ctr Atmospher Res, Boulder, CO 80307 USA. RP Doyle, JD (reprint author), USN, Res Lab, Marine Meteorol Div, 7 Grace Hopper Ave, Monterey, CA 93943 USA. EM doyle@nrlmry.navy.mil NR 50 TC 105 Z9 106 U1 0 U2 14 PU CO-ACTION PUBLISHING PI JARFALLA PA RIPVAGEN 7, JARFALLA, SE-175 64, SWEDEN SN 0280-6495 J9 TELLUS A JI Tellus Ser. A-Dyn. Meteorol. Oceanol. PD OCT PY 1999 VL 51 IS 5 BP 728 EP 748 DI 10.1034/j.1600-0870.1996.00014.x PG 21 WC Meteorology & Atmospheric Sciences; Oceanography SC Meteorology & Atmospheric Sciences; Oceanography GA 254KD UT WOS:000083609700014 ER PT J AU Chen, WY Van den Dool, HM AF Chen, WY Van den Dool, HM TI Significant change of extratropical natural variability and potential predictability associated with the El Nino/Southern Oscillation SO TELLUS SERIES A-DYNAMIC METEOROLOGY AND OCEANOGRAPHY LA English DT Article; Proceedings Paper CT Rossby-100 Symposium CY JUN 08-12, 1998 CL STOCKHOLM, SWEDEN ID HEMISPHERE WINTERTIME CIRCULATION; SEA-SURFACE TEMPERATURES; SOUTHERN OSCILLATION; TRANSIENT EDDIES; STORM TRACKS; MEAN-FLOW; FREQUENCY; ANOMALIES; MODEL; PROPAGATION AB Beyond the deterministic limit where the initial value sensitive predictability can hardly be found, the boundary condition dependent potential predictability is examined. The tropical anomalies of the opposite phases of El Nino/Southern Oscillation (ENSO) can significantly change the extratropical natural variability on a wide range of spatial and temporal scales. We address the impact on the low-frequency variability, such as the persistent blocking flows, and the high-frequency variability, represented primarily by the storm tracks. The NCEP/NCAR reanalyses are used for this investigation. Several diagnostics tools help to reveal the dynamical processes leading to the large change of the natural variability and the potential predictability in the extratropical latitudes between these two phases of the ENSO cycle. During El Nino winters, the principal storm tracks are steered more into the southern and Baja California region, by the much eastward extended subtropical jets. On the other hand, the storms are diverted more into the higher latitudes (Aleutians and Gulf of Alaska) during La Nina winters, when jetstreams are much weaker east of 160 degrees W. Although being passively steered to widely different regions, the high-frequency transients do feed back actively to strengthen and maintain the subtropical jet across the central North Pacific and also act to slow down the equatorward flank of the jet. The feedback by the transients is stronger during the El Nino than the La Nina winters, helping in maintaining stronger signals from the tropics for the El Nino winters. There is also a large change of low-frequency variability: much larger magnitude of kinetic energy and height variance during La Nina than El Nino winters. The local barotropic energy diagnosis reveals that, on average, the low-frequency components extract more energy from time-mean flows during La Nina than El Nino winters, helping in explaining the presence of much larger low-frequency variability during the La Nina winters. With stronger ENSO signals and weaker natural variability during El Nino winters, the potential predictability in the north Pacific sector is significantly higher, on these two counts, than during the La Nina winters. C1 NOAA, Natl Weather Serv, NCEP, Climate Predict Ctr, Washington, DC 20233 USA. RP Chen, WY (reprint author), NOAA, Natl Weather Serv, NCEP, Climate Predict Ctr, 5200 Auth Rd, Washington, DC 20233 USA. NR 36 TC 20 Z9 20 U1 0 U2 3 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0280-6495 J9 TELLUS A JI Tellus Ser. A-Dyn. Meteorol. Oceanol. PD OCT PY 1999 VL 51 IS 5 BP 790 EP 802 DI 10.1034/j.1600-0870.1999.00017.x PG 13 WC Meteorology & Atmospheric Sciences; Oceanography SC Meteorology & Atmospheric Sciences; Oceanography GA 254KD UT WOS:000083609700017 ER PT J AU Gates, R Wang, Y Ying, TN Hsu, S AF Gates, R Wang, Y Ying, TN Hsu, S TI A grinding map concept for optimization of ceramic machining SO TRIBOLOGY TRANSACTIONS LA English DT Article DE silicon nitride; grinding; diamond; optimization; grinding map; coolant ID DAMAGE AB This paper describes a systematic attempt to isolate various parameters that affect the material removal al rate for diamond grinding of silicon nitride ceramics. The influence of different coolants and operating parameters such as force, depth of cut, and diamond grit size on the material I removal rates under controlled conditions of single pass grinding is determined. Several parameters were developed to aid in interpretation of the grinding results. The parameters include grinding force coefficient, retained grinding efficiency and instantaneous grinding rate. A grinding map concept was developed to allow rapid visual evaluation of grinding performance for a given coolant and a set of operating conditions. The results suggest that material removal rates in grinding of silicon nitride ceramics can be increased through optimization of machining parameters and the proper use of suitable coolants. The major contribution to decreased grinding rates for silicon nitride machining in these tests was due to dulling of the diamond abrasive embedded in the grinding wheel. Significant coolant chemistry effects were observed as it affects the diamond dulling rate due to oxidative wear mechanisms. C1 NIST, Div Ceram, Gaithersburg, MD 20899 USA. RP Gates, R (reprint author), NIST, Div Ceram, Gaithersburg, MD 20899 USA. NR 11 TC 4 Z9 4 U1 1 U2 2 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 OCT PY 1999 VL 42 IS 4 BP 715 EP 722 DI 10.1080/10402009908982274 PG 8 WC Engineering, Mechanical SC Engineering GA 243MN UT WOS:000083002000004 ER PT J AU van den Berg, F Kubiak, R Benjey, WG Majewski, MS Yates, SR Reeves, GL Smelt, JH van der Linden, AMA AF van den Berg, F Kubiak, R Benjey, WG Majewski, MS Yates, SR Reeves, GL Smelt, JH van der Linden, AMA TI Emission of pesticides into the air SO WATER AIR AND SOIL POLLUTION LA English DT Article; Proceedings Paper CT Workshop on Fate of Pesticides in the Atmosphere Implications for Risk Assessment CY APR 22-24, 1998 CL DRIEBERGEN, NETHERLANDS DE air quality; application technique; emission factor; emission model; glasshouse; measurement method; pesticides; regional emissions; spray drift; volatilization ID METHYL-BROMIDE VOLATILIZATION; BEHAVIOR ASSESSMENT MODEL; RANDOM-WALK MODEL; AGRICULTURAL FIELDS; TRACE ORGANICS; WHEAT FIELD; SPRAY DRIFT; BARE SOIL; CLASSIFICATION; EVAPORATION AB During and after the application of a pesticide in agriculture, a substantial fraction of the dosage may enter the atmosphere and be transported over varying distances downwind of the target. The rate and extent of the emission during application, predominantly as spray particle drift, depends primarily on the application method (equipment and technique), the formulation and environmental conditions, whereas the emission after application depends primarily on the properties of the pesticide, soils, crops and environmental conditions. The fraction of the dosage that misses the target area may be high in some cases and more experimental data on this loss term are needed for various application types and weather conditions. Such data are necessary to test spray drift models, and for further model development and verification as well. Following application, the emission of soil fumigants and soil incorporated pesticides into the air can be measured and computed with reasonable accuracy, but further model development is needed to improve the reliability of the model predictions. For soil surface applied pesticides reliable measurement methods are available, but there is not yet a reliable model. Further model development is required which must be verified by field experiments. Few data are available on pesticide volatilization from plants and more field experiments are also needed to study the fate processes on the plants. Once this information is available, a model needs to be developed to predict the volatilization of pesticides from plants, which, again, should be verified with field measurements. For regional emission estimates, a link between data on the temporal and spatial pesticide use and a geographical information system for crops and soils with their characteristics is needed. C1 DLO, Winand Staring Ctr Integrated Land Soil & Water R, NL-6700 AC Wageningen, Netherlands. Staatliche Lehr & Forsch Anstalt Landwirtschaft W, D-67435 Neustadt, Germany. NOAA, Atmospher Sci Modeling Div, Air Resources Lab, Res Triangle Pk, NC 27711 USA. US Geol Survey, NERL, Water Res Dept, Sacramento, CA 95819 USA. ARS, US Salin Lab, USDA, Riverside, CA 92507 USA. Dow AgroSci, Letcombe Regis, Wantage OX12 9JT, Oxon, England. Natl Inst Publ Hlth & Environm, NL-3720 BA Bilthoven, Netherlands. RP van den Berg, F (reprint author), DLO, Winand Staring Ctr Integrated Land Soil & Water R, POB 125, NL-6700 AC Wageningen, Netherlands. RI de Voogt, Pim/C-5683-2017 OI de Voogt, Pim/0000-0001-9065-9797 NR 104 TC 122 Z9 123 U1 4 U2 42 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0049-6979 J9 WATER AIR SOIL POLL JI Water Air Soil Pollut. PD OCT PY 1999 VL 115 IS 1-4 BP 195 EP 218 DI 10.1023/A:1005234329622 PG 24 WC Environmental Sciences; Meteorology & Atmospheric Sciences; Water Resources SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences; Water Resources GA 243XT UT WOS:000083023300009 ER PT J AU Fulton, RA AF Fulton, RA TI Sensitivity of WSR-88D rainfall estimates to the rain-rate threshold and rain gauge adjustment: A flash flood case study SO WEATHER AND FORECASTING LA English DT Article ID HEAVY RAINFALL AB A strong thunderstorm produced a flash flood on the evening of 12 July 1996 in Buffalo Creek, Colorado, that caused two deaths and significant property damage. Most of the rain fell in a l-h time period from 2000 to 2100 MDT. The performance of the WSR-88D rainfall algorithm, Precipitation Processing System, was examined in derail to determine how well it performed. In particular the sensitivity to the algorithm's rain-rate threshold (hail cap) parameter and the performance of the gauge-radar adjustment subalgorithm on the resulting radar rainfall estimates were examined by comparison with available rain gauge data. It was determined that the WSR-88D rainfall algorithm overestimated the rainfall in general over the radar scanning domain for this event by about 60% relative to the rain gauges although the radar-derived rainfall for the hood-producing storm cell nearly matched the single gauge that sampled it. The derived rainfall over the radar scanning domain was not very sensitive to the setting of the rain-rate threshold parameter Lowering it reduced the overestimation in general bur did not bring the estimates satisfactorily close to unbiasedness. Other error sources were suggested, including use of an inappropriate Z-R relationship and/or radar reflectivity miscalibration. Relative importance of these sources could not be determined. The portion of the rainfall algorithm that adjusts the radar estimates using rain gauge data was tested to determine if it could have satisfactorily reduced the observed overestimation. It was found to have performed suboptimally due primarily to the methodology in the algorithm that forms the gauge-radar pairs. A simpler technique was proposed and tested, and the algorithm's performance was greatly enhanced as a result. Therefore the performance of the gauge-radar adjustment algorithm depends on the gauge-radar rainfall data that are passed to it, and that data are dependent on the method by which the pairs are formed. C1 NOAA, Natl Weather Serv, Hydrol Res Lab WOH1, Off Hydrol, Silver Spring, MD 20910 USA. RP Fulton, RA (reprint author), NOAA, Natl Weather Serv, Hydrol Res Lab WOH1, Off Hydrol, 1325 East West Highway, Silver Spring, MD 20910 USA. EM fulton@skipper.nws.noaa.gov NR 27 TC 15 Z9 18 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0882-8156 EI 1520-0434 J9 WEATHER FORECAST JI Weather Forecast. PD OCT PY 1999 VL 14 IS 5 BP 604 EP 624 DI 10.1175/1520-0434(1999)014<0604:SOWRET>2.0.CO;2 PG 21 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 249GD UT WOS:000083324200002 ER PT J AU Trapp, RJ Mitchell, ED Tipton, GA Effertz, DW Watson, AI Andra, DL Magsig, MA AF Trapp, RJ Mitchell, ED Tipton, GA Effertz, DW Watson, AI Andra, DL Magsig, MA TI Descending and nondescending tornadic vortex signatures detected by WSR-88Ds SO WEATHER AND FORECASTING LA English DT Article ID SEVERE FRONTAL RAINBAND; DOPPLER RADAR AB Tornadic vortex signatures (TVSs) of 52 tornadoes were identified and analyzed, then characterized as either descending or nondescending. This characterization refers to a known tendency of radar-observed tornadic vortices, namely, that of their initial detection aloft and then of their subsequent descent leading to tornadogenesis. Only 52% of the sampled TVSs descended according to this archetypal model. The remaining 48% were detected first near the ground and grew upward or appeared nearly simultaneously over a several kilometer depth; these represent primary modes of tornado development that have been explained theoretically. The descending-nondescending TVSs were stratified according to attributes of the tornado and TVS. Significantly, tornadoes within quasi-linear convective systems tended to be associated with nondescending TVSs, identification of which provided a mean tornado lead time of 5 min. Two case studies are presented for illustrative purposes. On 1 July 1997 in southern Minnesota, nondescending TVSs and associated tornadogenesis were revealed in the leading edge of a squall line, with a squall line-supercell merger, and later during that day, with the cyclonic bookend vortex of a bow echo. On 22 June 1995 in southern Colorado, a low-topped supercell storm produced a tornado that was associated with a descending TVS. C1 Univ Oklahoma, NOAA, Natl Severe Storms Lab, Norman, OK 73019 USA. Univ Oklahoma, Cooperat Inst Mesoscale Meteorol Studies, Norman, OK 73019 USA. NOAA, Natl Weather Serv, Wilmington, OH USA. NOAA, Natl Weather Serv, Chanhassen, MN USA. NOAA, Natl Weather Serv, Tallahassee, FL USA. NOAA, Natl Weather Serv, Norman, OK USA. NOAA, Operat Support Facil, Norman, OK USA. RP Trapp, RJ (reprint author), Natl Ctr Atmospher Res, MMM, Pob 3000, Boulder, CO 80307 USA. NR 33 TC 43 Z9 43 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0882-8156 J9 WEATHER FORECAST JI Weather Forecast. PD OCT PY 1999 VL 14 IS 5 BP 625 EP 639 DI 10.1175/1520-0434(1999)014<0625:DANTVS>2.0.CO;2 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 249GD UT WOS:000083324200003 ER PT J AU Stensrud, DJ Manikin, GS Rogers, E Mitchell, KE AF Stensrud, DJ Manikin, GS Rogers, E Mitchell, KE TI Importance of cold pools to NCEP mesoscale eta model forecasts SO WEATHER AND FORECASTING LA English DT Article ID NATIONAL-METEOROLOGICAL-CENTER; CONVECTIVE ADJUSTMENT SCHEME; REGIONAL-ANALYSIS SYSTEM; LARGE-SCALE ENVIRONMENTS; FLASH-FLOOD EVENTS; SQUALL LINE; PREDICTION; COORDINATE; VORTEX; STORMS AB The cold pool, a pool of evaporatively cooled downdraft air that spreads out horizontally along the ground beneath a precipitating cloud, is often a factor in severe weather and heavy precipitation events. Unfortunately, cold pools are not well sampled by the present observational network and are rarely depicted in numerical model initial conditions. A procedure to identify and insert cold pools into the 29-km Era Model is developed and tested on seven cases during 1995. Results suggest that when the large-scale forcing is strong, the inclusion of cold pools produces only slight changes in the forecasts. However, for the one case in which the large-scale forcing is relatively weak, the inclusion of cold pools produces significant changes in many of the model fields. These initial results, while not conclusive, suggest that the incorporation of cold pools, and other mesoscale features, map be important to the improvement of numerical guidance for severe weather and heavy precipitation forecasting. C1 NOAA, ERL, Natl Severe Storms Lab, Norman, OK 73069 USA. Natl Ctr Environm Predict, Environm Modeling Ctr, Camp Springs, MD USA. RP Stensrud, DJ (reprint author), NOAA, ERL, Natl Severe Storms Lab, 1313 Halley Circle, Norman, OK 73069 USA. NR 48 TC 20 Z9 20 U1 1 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0882-8156 J9 WEATHER FORECAST JI Weather Forecast. PD OCT PY 1999 VL 14 IS 5 BP 650 EP 670 DI 10.1175/1520-0434(1999)014<0650:IOCPTN>2.0.CO;2 PG 21 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 249GD UT WOS:000083324200005 ER PT J AU Houston, SH Shaffer, WA Powell, MD Chen, J AF Houston, SH Shaffer, WA Powell, MD Chen, J TI Comparisons of HRD and SLOSH surface wind fields in hurricanes: Implications for storm surge modeling SO WEATHER AND FORECASTING LA English DT Article ID KINEMATIC STRUCTURE; ANDREW LANDFALL; SOUTH FLORIDA; SEASON AB Surface wind observations analyzed by the Hurricane Research Division (HRD) were compared to those computed by the parametric wind model used in the National Weather Service Sea, Lake, and Overland Surges from Hurricanes (SLOSH) model's storm surge computations for seven cases in five recent hurricanes. In six cases, the differences between the SLOSH and HRD surface peak wind speeds were 6% or less, but in one case (Hurricane Emily of 1993) the SLOSH computed peak wind speeds were 15% less than the HRD. In all seven cases, statistics for the modeled and analyzed wind fields showed that for the region of strongest winds, the mean SLOSH wind speed was 14% greater than that of the HRD and the mean inflow angle for SLOSH was 19 degrees less than that of the HRD. The radii beyond the region of strongest winds in the seven cases had mean wind speed and inflow angle differences that were very small. The SLOSH computed peak storm surges usually compared closely to the observed values of storm surge in the region of the maximum wind speeds, except Hurricane Emily where SLOSH underestimated the peak surge. HRD's observation-based wind fields were input to SLOSH for storm surge hindcasts of Hurricanes Emily and Opal (1995). In Opal, the HRD input produced nearly the same computed storm surges as those computed from the SLOSH parametric wind model, and the calculated surge was insensitive to perturbations in the HRD wind held. For Emily, observation-based winds produced a computed storm surge that was closer to the peak observed surge, confirming that the computed surge in Pamlico Sound was sensitive to atmospheric forcing. Using real-time, observation-based winds in SLOSH would likely improve storm surge computations in landfalling hurricanes affected by synoptic and mesoscale factors that are not accounted for in parametric models (e.g., a strongly sheared environment, convective asymmetries, and stably stratified boundary layers). An accurate diagnosis of storm surge flooding, based on the actual track and wind fields could be supplied to emergency management agencies, government officials, and utilities to help with damage assessment and recovery efforts. C1 NOAA, HRD, AOML, Miami, FL 33149 USA. NOAA, NWS, OSD, Tech Dev Lab, Silver Spring, MD USA. RP Houston, SH (reprint author), NOAA, HRD, AOML, 4301 Rickenbacker Causeway, Miami, FL 33149 USA. RI Powell, Mark/I-4963-2013 OI Powell, Mark/0000-0002-4890-8945 NR 26 TC 55 Z9 55 U1 1 U2 11 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0882-8156 J9 WEATHER FORECAST JI Weather Forecast. PD OCT PY 1999 VL 14 IS 5 BP 671 EP 686 DI 10.1175/1520-0434(1999)014<0671:COHASS>2.0.CO;2 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 249GD UT WOS:000083324200006 ER PT J AU Junker, NW Schneider, RS Fauver, SL AF Junker, NW Schneider, RS Fauver, SL TI A study of heavy rainfall events during the great midwest flood of 1993 SO WEATHER AND FORECASTING LA English DT Article ID MESOSCALE CONVECTIVE COMPLEXES; UNITED-STATES; WEATHER SYSTEMS; PRECIPITATION; CIRCULATION AB A synoptic-dynamic climatology was constructed using all 24-h 2-in. (50.8 mm) or greater rainfall events in nine states affected by heavy rains and flooding from June through September 1993 using 6- or 12-h gridded analyses from the Regional Data Assimilation System and geostationary satellite imagery. Each of the 85 events was assigned a category (0-4) based on the areal coverage of the 3-in. (76.2 mm) or greater observed precipitation isohyet. A variety of meteorological fields and rules of thumb used by forecasters at the Hydrometeorological Prediction Center are investigated that may help identify the most likely location and scale of a convective precipitation event. The heaviest rain usually fell to the north (downwind) of the axis of highest 850-mb winds and moisture flux in an area of 850-mb warm temperature and equivalent potential temperature advection. The rainfall maximum also usually occurred to the north or northeast of the axis of highest 850-mb equivalent potential temperature. The scale and intensity of the rainfall appeared to be related to 1) the magnitude of the warm advection, 2) the 1000-500-mb mean relative humidity, 3) the breadth of the axis of stronger values of moisture transport feeding northward into a surface boundary, 4) the strength of low-level moisture flux convergence, and 5) the length of the low-level moisture flux convergence that was aligned along the mean flow upstream from the location of the rainfall maximum. The latter finding suggests that propagation plays an important role in modulating the scale and intensity of rainfall events. C1 NCEP, Hydrometeor Predict Ctr, Camp Springs, MD USA. NSSL, Storm Predict Ctr, Norman, OK USA. NWS, Charleston, SC USA. RP Junker, NW (reprint author), NOAA, NWS, 5200 Auth Rd,Room 410, Suitland, MD 20746 USA. NR 34 TC 40 Z9 45 U1 0 U2 6 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0882-8156 J9 WEATHER FORECAST JI Weather Forecast. PD OCT PY 1999 VL 14 IS 5 BP 701 EP 712 DI 10.1175/1520-0434(1999)014<0701:ASOHRE>2.0.CO;2 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 249GD UT WOS:000083324200008 ER PT J AU Birkenheuer, D AF Birkenheuer, D TI The effect of using digital satellite imagery in the LAPS moisture analysis SO WEATHER AND FORECASTING LA English DT Article ID LOCAL ANALYSIS; TEMPERATURE; SYSTEM AB The Local Analysis and Prediction System (LAPS) analyzes three-dimensional moisture as one component of its system. This paper describes the positive impact that simple 8-bit, remapped, routinely available imagery have on the LAPS moisture analysis above 500 hPa. A variational method adjusts the LAPS moisture analysis by minimizing differences between forward model-computed radiances and radiances from Advanced weather interactive Processing System (AWIPS) image-grade data from Geostationary Operational Environmental Satellite 8 (GOES-8). The three infrared channels used in the analysis will be routinely available to AWIPS workstations every 15 min. This technique improves LAPS upper-level dewpoint, reducing dewpoint temperature bias and root-mean-square error on the order of 0.5 and 1.5 K, respectively, as compared to Denver radiosonde observation data. Furthermore, it strongly exemplifies the objective analysis benefit of image-grade data, in addition to its well-known subjective utility. C1 NOAA, ERL, Forecast Syst Lab, CIRA,R E FS1, Boulder, CO 80303 USA. RP Birkenheuer, D (reprint author), NOAA, ERL, Forecast Syst Lab, CIRA,R E FS1, 325 Broadway, Boulder, CO 80303 USA. RI Birkenheuer, Daniel/E-7378-2015 NR 6 TC 18 Z9 25 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0882-8156 J9 WEATHER FORECAST JI Weather Forecast. PD OCT PY 1999 VL 14 IS 5 BP 782 EP 788 DI 10.1175/1520-0434(1999)014<0782:TEOUDS>2.0.CO;2 PG 7 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 249GD UT WOS:000083324200014 ER PT J AU Gemmill, WH Krasnopolsky, VM AF Gemmill, WH Krasnopolsky, VM TI The use of SSM/I data in operational marine analysis SO WEATHER AND FORECASTING LA English DT Article ID SPECIAL SENSOR MICROWAVE/IMAGER; SURFACE WIND SPEEDS; NEURAL NETWORKS; WATER-VAPOR; OCEAN; IMAGER; APPROXIMATION; PREDICTION; OPERATORS; RETRIEVAL AB The application of Special Sensor Microwave/Imager (SSM/I) multiparameter satellite retrievals in operational weather analysis and forecasting is addressed. More accurate multiparameter satellite retrievals are now available from an SSM/I neural network algorithm. It also provides greater areal coverage than some of the initial algorithms. These retrievals (ocean surface wind speed, columnar water vapor, and columnar liquid water), when observed together, provide a meteorologically consistent description of synoptic weather patterns over the oceans. Three SSM/I sensors are currently in orbit, which provide sufficient amounts of data to be used in a real-time operational environment. Several examples are presented to illustrate that important synoptic meteorological features such as fronts, storms, and convective areas can be identified and observed in the SSM/I fields retrieved by the new algorithm. The most recent version of the neural network algorithm retrieves simultaneously four geophysical parameters: ocean-surface wind speed, columnar water vapor, columnar liquid water, and sea surface temperature, allowing the knowledge of each variable to contribute directly to better accuracy in ocean surface wind speed retrievals. The neural network wind speed data were recently incorporated as a part of operational Global Data Assimilation System at the National Centers for Environmental Prediction. C1 NOAA, NWS, Natl Ctr Environm Predict, Environm Modeling Ctr,Ocean Modeling Branch, Camp Springs, MD 20746 USA. RP Gemmill, WH (reprint author), NOAA, NWS, Natl Ctr Environm Predict, Environm Modeling Ctr,Ocean Modeling Branch, 5200 Auth Rd,Rm 207, Camp Springs, MD 20746 USA. NR 30 TC 9 Z9 10 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0882-8156 J9 WEATHER FORECAST JI Weather Forecast. PD OCT PY 1999 VL 14 IS 5 BP 789 EP 800 DI 10.1175/1520-0434(1999)014<0789:TUOSID>2.0.CO;2 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 249GD UT WOS:000083324200015 ER PT J AU Bannister, ME Djuric, N Woitke, O Dunn, GH Chung, YS Smith, ACH Wallbank, B Berrington, KA AF Bannister, ME Djuric, N Woitke, O Dunn, GH Chung, YS Smith, ACH Wallbank, B Berrington, KA TI Absolute cross sections for near-threshold electron-impact excitation of Be-like C(2+), N(3+), and O(4+) ions SO INTERNATIONAL JOURNAL OF MASS SPECTROMETRY LA English DT Article DE excitation; collisions; merged beams; close coupling ID ENERGY-LOSS TECHNIQUE; 3S(2) S-1->3S3P P-3; COLLISIONAL EXCITATION; RESONANCE STRUCTURE; N=3 LEVELS; TRANSITIONS; BEAMS; RATES; IONIZATION; KR6+ AB Absolute total cross sections for electron-impact excitation of the Be-like C(2+), N(3+), and O(4+) ions have been measured near threshold using the merged electron-ion beams energy-loss (MEIBEL) technique and calculated using a close-coupling R-matrix (CCR) approach. The 2s(2) (1)S --> 2s2p (1)P(0) dipole-allowed. transition from the ground state was investigated for all three ions and satisfactory agreement between experiment and theory is found. In addition, calculations and measurements for the 2s2p (3)P(0) --> 2p(2) (3)P allowed transition from the metastable level of C(2+) are in excellent agreement. The sum of the cross sections for the 2s(2) (1)S --> 2s2p (3)P(0) and 2s2p (3)P(0) --> 2s2p (1)P(0) spin-forbidden transitions, not completely resolved by the MEIBEL technique, are measured for C(2+) and O(4+) and compared to CCR calculations scaled to account for the ground state and metastable fractions of the target ion beams. The results for these unresolved transitions are in reasonable agreement except for a resonance feature measured in the 2s2p (3)P(0) --> 2s2p (1)P(0) transition in C(2+) that is not predicted by theory. (C) 1999 Elsevier Science B.V. C1 Oak Ridge Natl Lab, Div Phys, Oak Ridge, TN 37831 USA. Univ Colorado, JILA, Boulder, CO 80309 USA. NIST, Boulder, CO 80309 USA. Chungnam Natl Univ, Taejon 305764, South Korea. UCL, Dept Phys & Astron, London WC1E 6BT, England. St Francis Xavier Univ, Antigonish, NS B2G 2W5, Canada. Sheffield Hallam Univ, Sch Sci & Math, Sheffield S1 1WB, S Yorkshire, England. RP Bannister, ME (reprint author), Oak Ridge Natl Lab, Div Phys, Oak Ridge, TN 37831 USA. EM bannister@mail.phy.ornl.gov NR 27 TC 11 Z9 11 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1387-3806 J9 INT J MASS SPECTROM JI Int. J. Mass Spectrom. PD SEP 27 PY 1999 VL 192 SI SI BP 39 EP 48 DI 10.1016/S1387-3806(99)00083-4 PG 10 WC Physics, Atomic, Molecular & Chemical; Spectroscopy SC Physics; Spectroscopy GA 243EZ UT WOS:000082985200006 ER PT J AU Folkins, I Loewenstein, M Podolske, J Oltmans, SJ Proffitt, M AF Folkins, I Loewenstein, M Podolske, J Oltmans, SJ Proffitt, M TI A barrier to vertical mixing at 14 km in the tropics: Evidence from ozonesondes and aircraft measurements SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID UPPER TROPOSPHERE; OZONE; TROPOPAUSE; STRATOSPHERE; CONVECTION; TRANSPORT; PACIFIC; WAVE; AIR AB We use ozonesondes launched from Samoa (14 degrees S) during the Pacific Exploratory Mission (PEM) Tropics A to show that O-3 mixing ratios usually start increasing toward stratospheric values near 14 km. This is well below the tropical tropopause las defined either in terms of lapse rate or cold point), which usually occurs between 16 and 17 km. We argue that the main reason for this discrepancy in height between the chemopause and tropopause is that there is very little convective detrainment of ozone-depleted marine boundary layer air above 14 km. We conjecture that the top of the Hadley circulation occurs at roughly 14 km, that convective penetration above this altitude is rare, and that air that is injected above this height subsequently participates in a slow vertical ascent into the stratosphere. The observed dependence of ozone on potential temperature in the transitional zone between the 14-km chemopause and the tropical tropopause is consistent with what would be expected from this hypothesis given calculated clear-sky heating rates and typical in situ ozone production rates in this region. An observed anticorrelation between ozone and equivalent potential temperature below 14 km is consistent with what would be expected from an overturning Hadley circulation, with some transport of high O-3/low theta(e) air from midlatitudes. We also argue that the positive correlations between O-3 and N2O in the transitional zone obtained during the 1994 Airborne Southern Hemisphere Ozone Experiment/Measurements for Assessing the Effects of Stratospheric Aircraft) (ASHOE/MAESA) campaign support the notion that air in this region does have trace elements of Stratospheric air las conjectured previously), so that some of the ozone in the transitional zone does originate from the stratosphere rather than being entirely produced in situ. C1 Dalhousie Univ, Dept Oceanog, Atmospher Sci Program, Halifax, NS B3H 4J1, Canada. Dalhousie Univ, Dept Phys, Atmospher Sci Program, Halifax, NS B3H 4J1, Canada. NASA, Div Earth Sci, Ames Res Ctr, Moffett Field, CA 94035 USA. NOAA, Climate Monitoring & Diagnost Aeron Lab, Boulder, CO 80303 USA. NOAA, Aeron Lab, Boulder, CO 80303 USA. RP Folkins, I (reprint author), Dalhousie Univ, Dept Oceanog, Atmospher Sci Program, Halifax, NS B3H 4J1, Canada. EM Ian.Folkins@dal.ca; mloewenstein@mail.src.nasa.gov; soltmans@cmdl.noaa.gov; proffitt@al.noaa.gov NR 19 TC 155 Z9 155 U1 2 U2 11 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD SEP 27 PY 1999 VL 104 IS D18 BP 22095 EP 22102 DI 10.1029/1999JD900404 PG 8 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 239UZ UT WOS:000082789200003 ER PT J AU Cooke, WF Liousse, C Cachier, H Feichter, J AF Cooke, WF Liousse, C Cachier, H Feichter, J TI Construction of a 1 degrees x 1 degrees fossil fuel emission data set for carbonaceous aerosol and implementation and radiative impact in the ECHAM4 model SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Review ID GENERAL-CIRCULATION MODEL; LONG-RANGE TRANSPORT; ATMOSPHERIC PARTICULATE MATTER; PARTICLE-SIZE DISTRIBUTION; CLOUD-WATER-CONTENT; USE MOTOR VEHICLES; BLACK CARBON; ELEMENTAL CARBON; ORGANIC-CARBON; LIGHT-ABSORPTION AB Global-scale emissions of carbonaceous aerosol from fossil fuel usage have been calculated with a resolution of 1 degrees x 1 degrees. Emission factors for black and organic carbon have been gathered from the literature and applied to domestic, transport, and industrial combustion of various fuel types. In addition, allowance has been made for the level of development when calculating emissions from a country. Emissions have been calculated for 185 countries for the domestic, industrial, and transport sectors using a fuel usage database published by the United Nations [1993]. Some inconsistencies were found for a small number of countries with regard to the distribution of fuel usage between the industrial and domestic sectors. Care has been taken to correct for this using data from the fuel use database for the period 1970-1990. Emissions based on total particulate matter (TPM) and submicron emission factors have been calculated. Global emissions for 1984 of black carbon total 6.4 TgC yr(-1) and organic carbon emissions of 10.1 TgC yr(-1) were found using bulk aerosol emission factors, while global black carbon emissions of 5.1 TgC yr(-1) and organic carbon emissions of 7.0 TgC yr(-1) were found using submicron emission factors. Use of the database is quite flexible and can be easily updated as emission factor data are updated. There is at least a factor of 2 uncertainty in the derived emissions due to the lack of exactly appropriate emission data. The emission fields have been introduced into the ECHAM4 atmospheric general circulation model and run for 5 model years. Monthly mean model results are compared to measurements in regions influenced by anthropogenic fossil fuel emissions. The resultant aerosol fields have been used to calculate the instantaneous solar radiative forcing at the top of the troposphere due to an external mixture of fossil fuel derived black carbon and organic carbon aerosol. Column burdens of 0.143 mgBC m(-2) and 0.170 mgOC m(-2) were calculated. Because of secondary production of organic carbon aerosol, it is recommended that the burden of organic carbon aerosol be doubled to 0.341 mgOC m(-2). The resultant forcing when clouds are included is +0.173 W m(-2) for black carbon and -0.024 W m(-2) for organic carbon (x2) as a global annual average. The results are compared to previous works, and the differences are discussed. C1 Ctr Faibles Radioact, Lab Mixte CNRS CEA, F-91198 Gif Sur Yvette, France. Max Planck Inst Meteorol, D-20146 Hamburg, Germany. RP Cooke, WF (reprint author), Geophys Fluid Dynam Lab, POB 308,Forrestal Campus, Princeton, NJ 08542 USA. EM wfc@gfdl.gov NR 131 TC 386 Z9 402 U1 7 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 SEP 27 PY 1999 VL 104 IS D18 BP 22137 EP 22162 DI 10.1029/1999JD900187 PG 26 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 239UZ UT WOS:000082789200006 ER PT J AU Feingold, G Frisch, AS Stevens, B Cotton, WR AF Feingold, G Frisch, AS Stevens, B Cotton, WR TI On the relationship among cloud turbulence, droplet formation and drizzle as viewed by Doppler radar, microwave radiometer and lidar SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID MARINE BOUNDARY-LAYER; STRATOCUMULUS CLOUDS; CONDENSATION NUCLEI; STRATIFORM CLOUD; CUMULUS CLOUDS; STRATUS; ASTEX; LIQUID; WATER AB Cloud radar, microwave radiometer, and lidar remote sensing data acquired during the Atlantic Stratocumulus Transition Experiment (ASTEX) are analyzed to address the relationship between (1) drop number concentration and cloud turbulence as represented by vertical velocity and vertical velocity variance and (2) drizzle formation and cloud turbulence. Six cases, each of about 12 hours duration, are examined; three of these cases are characteristic of nondrizzling boundary layers and three of drizzling boundary layers. In all cases, microphysical retrievals are only performed when drizzle is negligible (radar reflectivity <-17 dBZ). It is shown that for the cases examined, there is, in general, no correlation between drop concentration and cloud base updraft strength, although for two of the nondrizzling cases exhibiting more classical stratocumulus features, these two parameters are correlated. On drizzling days, drop concentration and cloud-base vertical velocity were either not correlated or negatively correlated. There is a significant positive correlation between drop concentration and mean in-cloud vertical velocity variance for both nondrizzling boundary layers (correlation coefficient r = 0.45) and boundary layers that have experienced drizzle (r = 0.38). In general, there is a high correlation (r > 0.5) between radar reflectivity and in-cloud vertical velocity variance, although one of the boundary layers that experienced drizzle exhibited a negative correlation between these parameters. However, in the subcloud region, all boundary layers that experienced drizzle exhibit a negative correlation between radar reflectivity and vertical velocity variance. C1 NOAA, Cooperat Inst Res Atmosphere, Environm Technol Lab, Boulder, CO 80303 USA. Univ Calif Los Angeles, Dept Atmospher Sci, Los Angeles, CA 90095 USA. Colorado State Univ, Dept Atmospher Sci, Ft Collins, CO 80523 USA. RP Feingold, G (reprint author), NOAA, Cooperat Inst Res Atmosphere, Environm Technol Lab, 325 Broadway, Boulder, CO 80303 USA. EM gfeingold@etl.noaa.gov RI Stevens, Bjorn/A-1757-2013; Feingold, Graham/B-6152-2009 OI Stevens, Bjorn/0000-0003-3795-0475; NR 25 TC 14 Z9 14 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 SEP 27 PY 1999 VL 104 IS D18 BP 22195 EP 22203 DI 10.1029/1999JD900482 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 239UZ UT WOS:000082789200010 ER PT J AU Fung, KK Ramaswamy, V AF Fung, KK Ramaswamy, V TI On shortwave radiation absorption in overcast atmospheres SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID DELTA-EDDINGTON APPROXIMATION; SATELLITE MEASUREMENTS; SOLAR-RADIATION; WATER CLOUDS; SURFACE; MODEL; FLUX; PARAMETERIZATION; ALBEDO; CLEAR AB Using a numerical model of solar radiative transfer that is calibrated against benchmark computations, it is shown that atmospheric water vapor, together with the microphysical characteristics of water drops (liquid water path and effective radius), plays an important role in the total solar spectrum reflection and absorption in overcast skies. For any specific cloud type, the water vapor column above the cloud and the presence of saturated water vapor inside the cloud contribute significantly to atmospheric absorption. These factors also affect the relationship between the net shortwave fluxes at the top and bottom of overcast atmospheres, in particular, inhibiting a general universal linkage between these two quantities. Thus neglect of details concerning the vertical location, extent, and microphysical aspects of clouds can lead to biases in the inference of surface irradiance using top-of-the-atmosphere measurements. C1 Princeton Univ, NOAA, GFDL, Atmospher & Ocean Sci Program, Princeton, NJ 08542 USA. RP Fung, KK (reprint author), Princeton Univ, NOAA, GFDL, Atmospher & Ocean Sci Program, POB 308, Princeton, NJ 08542 USA. NR 22 TC 4 Z9 6 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 SEP 27 PY 1999 VL 104 IS D18 BP 22233 EP 22241 DI 10.1029/1999JD900457 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 239UZ UT WOS:000082789200013 ER PT J AU Zou, X Vandenberghe, F Wang, B Gorbunov, ME Kuo, YH Sokolovskiy, S Chang, JC Sela, JG Anthes, RA AF Zou, X Vandenberghe, F Wang, B Gorbunov, ME Kuo, YH Sokolovskiy, S Chang, JC Sela, JG Anthes, RA TI A ray-tracing operator and its adjoint for the use of GPS/MET refraction angle measurements SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID GLOBAL POSITIONING SYSTEM; RADIO OCCULTATION; EARTHS ATMOSPHERE; ASSIMILATION AB The development of small, high-performance instruments to receive Global Positioning System (GPS) signals has created an opportunity for active remote sounding of the Earth's atmosphere by radio occultation techniques. A prototype demonstration of this capability has been provided by the GPS Meteorology (GPS/MET) experiment. Although it was shown that high vertical resolution profiles of atmospheric refractivity, temperature, and geopotential height of constant pressure levels can be derived from the GPS measurements, with high accuracy under many circumstances, many issues remain. These include the existence of multipath propagation, the ambiguity between water vapor and temperature in moist regions of the atmosphere, and the difficulty in retrieving an accurate refractivity profile from the GPS refraction angle measurements over regions where the horizontal gradient of the refractivity is large. The aim of this paper is to begin the development of a methodology for incorporating the GPS "raw" measurements (refraction angles) directly into numerical weather analysis and/or prediction systems in order to alleviate the above mentioned problems. First, a ray-tracing observation operator that links the atmospheric state to the GPS refraction angle measurements is developed, the physics and numerics involved are described, and the simulated refraction angles, based on the NOAA National Centers for Environmental Prediction (NCEP) global analysis, are compared with the observed GPS/MET refraction angle measurements. Second, the tangent linear and adjoint of the ray-tracing operator are developed. These three operators are required for the direct use of GPS refraction angle measurements in a variational data analysis system. A single observation experiment reveals that the direct use of GPS refraction angles in a variational analysis causes changes in the temperature and specific humidity fields that are not limited to the occultation location but in an elongated band of +/-300 km in its occultation plane. On a-levels, changes from the use of one GPS occultation occur in an area of about 600 km x 600 km large which is centered around the ray perigee point. Finally, the advantages and disadvantages are discussed for the use of the GPS refractivities versus refraction angles. Errors made by using local estimates of refractivity are also assessed. C1 Florida State Univ, Dept Meteorol, Tallahassee, FL 32306 USA. Natl Ctr Atmospher Res, Boulder, CO 80307 USA. Chinese Acad Sci, LASG, Inst Atmospher Phys, Beijing, Peoples R China. Russian Acad Sci, Inst Atmospher Phys, Moscow 109017, Russia. Cent Weather Bur, Taipei, Taiwan. Natl Ctr Environm Predict, Camp Springs, MD 20233 USA. Univ Corp Atmospher Res, Boulder, CO 80303 USA. RP Zou, X (reprint author), Florida State Univ, Dept Meteorol, 404 Love Bldg, Tallahassee, FL 32306 USA. EM zou@met.fsu.edu RI Wang, Bin/D-9724-2012; Wang, Bin/P-9121-2014 OI Wang, Bin/0000-0002-3133-7197; Wang, Bin/0000-0001-7374-3786 NR 25 TC 69 Z9 87 U1 0 U2 5 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 SEP 27 PY 1999 VL 104 IS D18 BP 22301 EP 22318 DI 10.1029/1999JD900450 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 239UZ UT WOS:000082789200019 ER PT J AU Matthews, MR Anderson, BP Haljan, PC Hall, DS Wieman, CE Cornell, EA AF Matthews, MR Anderson, BP Haljan, PC Hall, DS Wieman, CE Cornell, EA TI Vortices in a Bose-Einstein condensate SO PHYSICAL REVIEW LETTERS LA English DT Article ID VORTEX STABILITY; GASES; CREATION; STATE AB We have created vortices in two-component Bose-Einstein condensates. The vortex state was created through a coherent process involving the spatial and temporal control of interconversion between the two components. Using an interference technique, we map the phase of the vortex state to confirm that it possesses angular momentum. We can create vortices in either of the two components and have observed differences in the dynamics and stability. C1 Univ Colorado, Natl Inst Stand & Technol, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. Univ Colorado, Dept Phys, Boulder, CO 80309 USA. RP Matthews, MR (reprint author), Univ Colorado, Natl Inst Stand & Technol, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. RI Anderson, Brian/A-2286-2009 OI Anderson, Brian/0000-0002-0442-7867 NR 23 TC 1133 Z9 1146 U1 6 U2 45 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 SEP 27 PY 1999 VL 83 IS 13 BP 2498 EP 2501 DI 10.1103/PhysRevLett.83.2498 PG 4 WC Physics, Multidisciplinary SC Physics GA 238HV UT WOS:000082705600005 ER PT J AU Dhanasekaran, T Grodkowski, J Neta, P Hambright, P Fujita, E AF Dhanasekaran, T Grodkowski, J Neta, P Hambright, P Fujita, E TI p-terphenyl-sensitized photoreduction of CO2 with cobalt and iron porphyrins. Interaction between CO and reduced metalloporphyrins SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID TRANSITION-METAL COMPLEXES; CARBON-DIOXIDE ACTIVATION; ELECTROCATALYTIC REDUCTION; ELECTROCHEMICAL REDUCTION; PHOTOCHEMICAL REDUCTION; HOMOGENEOUS CATALYSIS; FREE-RADICALS; ONE-ELECTRON; MACROCYCLES; POTENTIALS AB Iron and cobalt porphyrins (FeP and CoP) are utilized as electron-transfer mediators to effect photochemical reduction of CO2 in homogeneous solutions. The species that activate and reduce CO2 are the (FeP)-P-0 and (CoP)-P-0 formed by reduction of the starting materials. Reduction of the metalloporphyrins (MP) is achieved by photolysis in dimethylformamide or acetonitrile solutions containing triethylamine (TEA) as a reductive quencher. The photoreduction is efficient for the (MP)-P-III --> (MP)-P-II stage and probably occurs by an intramolecular electron transfer from an axially bound TEA. However, TEA does not bind to the reduced metal complexes, and the quantum efficiency is much lower for the subsequent reduction steps. Considerably higher quantum yields are obtained by adding p-terphenyl (TP) as a sensitizer. TP is very effectively photoreduced by TEA to form the radical anion, TP.-, which has a sufficiently negative reduction potential to reduce (CoP)-P-I and (FeP)-P-I rapidly to their MOP state. The rate constants for these reactions, determined by pulse radiolysis, are found to be nearly diffusion-controlled. The quantum yield for the reduction of (MP)-P-II to (MP)-P-I and for reduction of CO2 to CO are increased by more than an order of magnitude in the presence of TP. Side reactions involve hydrogenation of the porphyrin ring and production of Hz. The hydrogenated porphyrins also catalyze reduction of CO2, but the photochemical production of CO eventually stops. This limit on catalytic activity is due to destruction of the porphyrin macrocycle and accumulation of CO. CO can bind strongly to (FeP)-P-II and to (FeP)-P-I but not to (FeP)-P-0, as demonstrated by electrochemical measurements and by optical spectra of the species produced by sodium reduction in tetrahydrofuran in the presence and absence of CO. Although binding of CO to (FeP)-P-II and FeIP should not interfere with the formation of (FeP)-P-0, the active catalyst, the potential for reduction of (FeP)-P-I to (FeP)-P-0 becomes more negative. However, CO probably binds to the hydrogenated products thereby inhibiting the catalytic process. C1 Natl Inst Stand & Technol, Phys & Chem Properties Div, Gaithersburg, MD 20899 USA. Howard Univ, Dept Chem, Washington, DC 20059 USA. Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. RP Neta, P (reprint author), Natl Inst Stand & Technol, Phys & Chem Properties Div, Gaithersburg, MD 20899 USA. RI Fujita, Etsuko/D-8814-2013 NR 40 TC 65 Z9 65 U1 4 U2 37 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD SEP 23 PY 1999 VL 103 IS 38 BP 7742 EP 7748 DI 10.1021/jp991423u PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 239RF UT WOS:000082782900027 ER PT J AU Cooper, MA Holle, R Lopez, R AF Cooper, MA Holle, R Lopez, R TI Recommendations for lightning safety SO JAMA-JOURNAL OF THE AMERICAN MEDICAL ASSOCIATION LA English DT Letter C1 Univ Illinois, Chicago, IL 60680 USA. Natl Weather Serv, Natl Severe Storms Lab, NOAA, Norman, OK 73069 USA. RP Cooper, MA (reprint author), Univ Illinois, Chicago, IL 60680 USA. NR 5 TC 10 Z9 10 U1 0 U2 1 PU AMER MEDICAL ASSOC PI CHICAGO PA 515 N STATE ST, CHICAGO, IL 60610 USA SN 0098-7484 J9 JAMA-J AM MED ASSOC JI JAMA-J. Am. Med. Assoc. PD SEP 22 PY 1999 VL 282 IS 12 BP 1132 EP 1133 DI 10.1001/jama.282.12.1132-a PG 2 WC Medicine, General & Internal SC General & Internal Medicine GA 236JJ UT WOS:000082596200025 PM 10501113 ER PT J AU Lue, L Kiselev, SB AF Lue, L Kiselev, SB TI Crossover behavior in dilute polymer solutions: Square-well chains SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID CONFORMATIONAL SPACE RENORMALIZATION; LIQUID-LIQUID EQUILIBRIA; SELF-AVOIDING WALKS; THERMODYNAMIC PERTURBATION-THEORY; MONTE-CARLO SIMULATION; 2ND VIRIAL-COEFFICIENT; DOMB-JOYCE MODEL; THETA-POINT; EXCLUDED-VOLUME; 3 DIMENSIONS AB Monte Carlo simulations for model polymer chains composed of hard spheres with square-well attractions were performed to find a precise relation between the parameters of a crossover theory and the parameters of the square-well chain. For sufficiently large bond lengths, there was a direct relation between the effective parameters of the crossover theory and the second- and third-virial coefficients of the square-well atoms. For the systems under study, the theta temperature is close to the Boyle temperature of the disconnected monomers, is mainly dependent on the details of the monomer-monomer interactions, and is only weakly dependent on the bond length of the chain. Above the theta temperature, the crossover theory is in good agreement with the simulation data. Near the theta point, the main effect of tricritical corrections is a shift in the critical amplitudes. Other effects are extremely small. The simulation data are consistent with the tricritical crossover theory. However, more precise data are needed to quantitatively test the tricritical crossover theory. (C) 1999 American Institute of Physics. [S0021-9606(99)50536-9]. C1 Natl Inst Stand & Technol, Phys & Chem Properties Div, Boulder, CO 80303 USA. Colorado Sch Mines, Dept Chem Engn & Petr Refining, Golden, CO 80401 USA. RP Natl Inst Stand & Technol, Phys & Chem Properties Div, M-S 838,325 Broadway, Boulder, CO 80303 USA. RI Lue, Leo/E-7846-2011 OI Lue, Leo/0000-0002-4826-5337 NR 79 TC 5 Z9 5 U1 0 U2 5 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 0021-9606 EI 1089-7690 J9 J CHEM PHYS JI J. Chem. Phys. PD SEP 22 PY 1999 VL 111 IS 12 BP 5580 EP 5592 DI 10.1063/1.479816 PG 13 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 234VC UT WOS:000082504200034 ER PT J AU Robey, SW AF Robey, SW TI Mg/GaAs(001): A highly anisotropic reaction morphology SO APPLIED PHYSICS LETTERS LA English DT Article ID MOLECULAR-BEAM EPITAXY; GROWTH; GAAS AB The reaction of Mg thin films with a Ga-stabilized 4x2 GaAs(001) surface was observed to produce elongated, wire-like structures with widths on the order of 50 nm and lengths up to 1000 nm. These structures are composed of an epitaxial, cubic phase and develop asymmetrically, with the elongated direction along GaAs[110]. In situ electron diffraction, Auger spectroscopy, and ex situ atomic force microscopy were used to investigate this interesting reaction morphology. A potential formation mechanism is proposed in which migration of Ga or Ga-rich "droplets" across the GaAs surface leads to the formation of a ridge of Mg3As2 that is aligned preferentially along [110] due to strain and/or chemical anisotropy. (C) 1999 American Institute of Physics. [S0003-6951(99)02638-8]. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Robey, SW (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NR 13 TC 2 Z9 2 U1 2 U2 9 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD SEP 20 PY 1999 VL 75 IS 12 BP 1754 EP 1756 DI 10.1063/1.124809 PG 3 WC Physics, Applied SC Physics GA 235NE UT WOS:000082547100034 ER PT J AU Fu, JC Troy, CA Phillips, PJ AF Fu, JC Troy, CA Phillips, PJ TI A matching pursuit approach to small drill bit breakage prediction SO INTERNATIONAL JOURNAL OF PRODUCTION RESEARCH LA English DT Article ID WAVELET AB Wavelet-based pattern classification methods, which have been used extensively in imaging applications, have barely been explored in machining monitoring and diagnostic systems. Although the engineering literature recognizes wavelet methodologies as a practical alternative to the FFT for signals containing nonstationary information, most of it concerns only the Wavelet Transform. The WT can detect time-localized pre-failure machining signals, but it leaves two practical questions unanswered. The first is how to post-process the wavelet coefficients (the WT output) to extract the needed information. The second is what method to use for 'scanning' the signal with overlapping windows, since the WT covers only a short segment of the input signal. The Matching Pursuit (MP) approach handles both of these problems in a straightforward manner. As a pattern recognition method, it is adaptable to specific machining diagnostic tasks and eliminates the post-processing requirement. The scanning technique is likewise built into the algorithm, making customized windowing methods unnecessary. MP methods, which are widely used in imaging applications such as face recognition, are easily adapted to one-dimensional signals. Moreover, the MP framework can be tailored to the needs of specific applications through several parameters, such as the wavelet family, which are left to the user's discretion. In this paper, we present an MP implementation for small drill-bit breakage prediction. During bit failure, the small-bit thrust cutting force signal is characterized by two types of transients. We show that the MP detects these transients more effectively than an earlier method (also devised by the authors) based on the Discrete Wavelet Transform (DWT). C1 DaYeh Univ, Chang Hwa 51505, Taiwan. NIST, Gaithersburg, MD 20899 USA. RP Fu, JC (reprint author), DaYeh Univ, 112 Shan Jean Rd, Chang Hwa 51505, Taiwan. NR 18 TC 4 Z9 4 U1 0 U2 0 PU TAYLOR & FRANCIS LTD PI LONDON PA ONE GUNPOWDER SQUARE, LONDON EC4A 3DE, ENGLAND SN 0020-7543 J9 INT J PROD RES JI Int. J. Prod. Res. PD SEP 20 PY 1999 VL 37 IS 14 BP 3247 EP 3261 DI 10.1080/002075499190266 PG 15 WC Engineering, Industrial; Engineering, Manufacturing; Operations Research & Management Science SC Engineering; Operations Research & Management Science GA 234TC UT WOS:000082499600007 ER PT J AU Sharma, S Barrie, LA Plummer, D McConnell, JC Brickell, PC Levasseur, M Gosselin, M Bates, TS AF Sharma, S Barrie, LA Plummer, D McConnell, JC Brickell, PC Levasseur, M Gosselin, M Bates, TS TI Flux estimation of oceanic dimethyl sulfide around North America SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID BIOGENIC SULFUR EMISSIONS; CENTRAL ARCTIC-OCEAN; BOUNDARY-LAYER; MARINE ATMOSPHERE; SEA ICE; SEASONAL-VARIATIONS; ATLANTIC-OCEAN; GAS-EXCHANGE; OZONE; OXIDATION AB Simultaneous measurements of atmospheric and surface water dimethyl sulfide (DMS) concentrations were taken aboard the icebreaker USCGC Polar Sea from July to October 1994, as part of a joint Canada/United States circumnavigation of North America, an expedition with a unique Arctic Ocean transect. Atmospheric DMS concentrations around North America varied between 0.25 and 50 nmol m(-3) (mean = 5.1 nmol m(-3), sigma = 8.5 nmol m(-3), n = 89) with highest values occurring near (south of) the Arctic Ice edge. Surface water DMS concentrations ranged between 0.1 and 12.6 nmol L-1 (mean = 2.2 nmol L-1, sigma = 2.7 nmol L-1, n = 46) with highest values in the western Arctic Ocean and off the U.S. east coast, near the Sargasso sea. In the Arctic Ocean, maximum concentrations in air and water were found along the ice edge in the Chukchi Sea region. Atmospheric DMS decay rates of 68% per day and 38% per day were deduced from observations between 70 degrees and 76 degrees N (continental shelf and slope of Chukchi Sea) on the west side and between 80 degrees and 90 degrees N (central Arctic Ocean) for the east side of the Arctic Ocean, respectively. Ocean to atmosphere flux estimates of DMS were determined using the Liss-Merlivat empirical dependence of exchange coefficient on wind speed, DMS air concentrations, Henry's law constants, and DMS water concentrations. DMS fluxes varied between 0.0017 and 30 mu mol m(-2) d(-1), respectively, with higher fluxes in regions with open water. The Arctic Ocean contributed 0.063 Tg S (DMS) (0.4% of DMS from the world oceans) during the summer of 1994. A simple one-dimensional (1-D) photochemical box model, applied to six case studies, showed that the atmospheric lifetime of DMS in the high Arctic was 2.5 to 8 days, whereas at 16 degrees-33 degrees N it was 1 to 2 days. Modeled DMS decay rates for these regions, using the 1-D model, accounted for only 33% of the measured decay rate. This result also suggests that halogen chemistry, reactions with Br/BrO, may be an important sink for DMS in the Arctic atmosphere. C1 Atmospher Environm Serv, Downsview, ON M3H 5T4, Canada. Univ Quebec, Dept Oceanog, Rimouski, PQ G5L 3A1, Canada. Inst Maurice Lamontagne, Dept Fisheries & Oceans, Mont Joli, PQ G5H 3Z4, Canada. York Univ, Dept Earth & Space Sci, N York, ON M3J 1P3, Canada. NOAA, Pacific Marine Environm Lab, Seattle, WA 98115 USA. RP Atmospher Environm Serv, 4905 Dufferin St, Downsview, ON M3H 5T4, Canada. EM sangeeta.sharma@ec.gc.ca RI Gosselin, Michel/B-4477-2014; Bates, Timothy/L-6080-2016 OI Gosselin, Michel/0000-0002-1044-0793; NR 72 TC 33 Z9 34 U1 0 U2 9 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 SEP 20 PY 1999 VL 104 IS D17 BP 21327 EP 21342 DI 10.1029/1999JD900207 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 238BC UT WOS:000082690200009 ER PT J AU Dickerson, RR Rhoads, KP Carsey, TP Oltmans, SJ Burrows, JP Crutzen, PJ AF Dickerson, RR Rhoads, KP Carsey, TP Oltmans, SJ Burrows, JP Crutzen, PJ TI Ozone in the remote marine boundary layer: A possible role for halogens SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID PACIFIC AIR MASSES; PHOTOCHEMICAL HISTORIES; POLAR SUNRISE; COLUMN OZONE; INDIAN-OCEAN; POINT-ARENA; TROPOSPHERE; CHEMISTRY; PHOTOLYSIS; CHLORINE AB On the spring 1995 cruise of the National Oceanic and Atmospheric Administration research vessel Malcolm Baldrige, we measured very large diurnal variations in ozone concentrations in the marine boundary layer. Average diurnal variations of about 32% of the mean were observed over the tropical Indian Ocean. We simulated these observations with the Model of Chemistry in Clouds and Aerosols, a photochemical box model with detailed aerosol chemistry. The model was constrained with photolysis rates, humidity, aerosol concentrations, NO, CO, and O-3 specified by shipboard observations and ozonesondes. Conventional homogeneous chemistry, where ozone photolysis to O(D-1) and HOx chemistry dominate ozone destruction, can account for a diurnal variation of only about 12%. On wet sea-salt aerosols (at humidities above the deliquescence point), absorption of HOBr leads to release of BrCl and Br-2, which photolyze to produce Br atoms that may provide an additional photochemical ozone sink. After 8 days of simulation, these Br atoms reach a peak concentration of 1.2 x 10(7) cm(-3) at noon and destroy ozone through a catalytic cycle involving BrO and HOBr. Reactive Br lost to HBr can be absorbed into the aerosol phase and reactivated. The model predicts a diurnal variation in O-3 of 22% with aerosol-derived Br reaction explaining much, but not all, of the observed photochemical loss. The lifetime of ozone under these conditions is short, about 2 days. These results indicate that halogens play an important role in oxidation processes and the ozone budget in parts of the remote marine boundary layer. C1 Univ Maryland, Dept Meteorol, College Pk, MD 20742 USA. Univ Maryland, Dept Chem, College Pk, MD 20742 USA. Univ Bremen, Inst Umweltphys, Fernerkundung, FBI, D-28334 Bremen, Germany. NOAA, Atlantic Oceanog & Meteorol Lab, Ocean Chem Div, Miami, FL 33149 USA. Max Planck Inst Chem, Abt Luftchem, D-55020 Mainz, Germany. NOAA, Climate Monitoring & Diagnost Lab, Boulder, CO 80303 USA. RP Dickerson, RR (reprint author), Univ Maryland, Dept Meteorol, 3433 CSS Bldg, College Pk, MD 20742 USA. EM russ@atmos.umd.edu RI Crutzen, Paul/F-6044-2012; Carsey, Thomas/B-7939-2014; Dickerson, Russell/F-2857-2010; Burrows, John/B-6199-2014 OI Carsey, Thomas/0000-0001-9964-5092; Dickerson, Russell/0000-0003-0206-3083; Burrows, John/0000-0002-6821-5580 NR 54 TC 104 Z9 105 U1 0 U2 12 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 SEP 20 PY 1999 VL 104 IS D17 BP 21385 EP 21395 DI 10.1029/1999JD900023 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 238BC UT WOS:000082690200013 ER PT J AU Reichle, HG Anderson, BE Connors, VS Denkins, TC Forbes, DA Gormsen, BB Langenfelds, RL Neil, DO Nolf, SR Novelli, PC Pougatchev, NS Roell, MM Steele, LP AF Reichle, HG Anderson, BE Connors, VS Denkins, TC Forbes, DA Gormsen, BB Langenfelds, RL Neil, DO Nolf, SR Novelli, PC Pougatchev, NS Roell, MM Steele, LP TI Space shuttle based global CO measurements during April and October 1994, MAPS instrument, data reduction, and data validation SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID CARBON-MONOXIDE; RETRIEVAL AB The Measurement of Air Pollution From Satellites (MAPS) experiment flew as a payload aboard the space shuttle during April and October 1994. The instrument and the data reduction procedure were modified from earlier flights in 1981 and 1984. The modifications to both are described, and selected portions of the data are compared to concurrent aircraft borne direct measurements that had been carefully intercalibrated. In addition, the data acquired in 1984 were reprocessed using the new data reduction procedure, and the reprocessed data were compared to aircraft data acquired in 1984. The results of these comparisons indicate that the large bias error in the 1984 MAPS data has been reduced to about 10%. C1 N Carolina State Univ, Dept Marine Earth & Atmospher Sci, Raleigh, NC 27606 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. SpaceTec Inc, Hampton, VA 23666 USA. Sci Applicat Int Corp, Hampton, VA 23666 USA. CSIRO, Div Atmospher Res, Aspendale, Vic 3195, Australia. CSC, Hampton, VA 23666 USA. NOAA, Climate Monitoring & Diagnost Lab, Boulder, CO 80303 USA. Christopher Newport Univ, Dept Phys Comp Sci & Engn, Newport News, VA 23606 USA. RP Reichle, HG (reprint author), N Carolina State Univ, Dept Marine Earth & Atmospher Sci, Box 8208, Raleigh, NC 27606 USA. EM henry_reichle@ncsu.edu; s.r.nolf@larc.nasa.gov; pnovelli@cmdl.noaa.gov; n.s.pougatchev@larc.nasa.gov RI Steele, Paul/B-3185-2009; Langenfelds, Raymond/B-5381-2012 OI Steele, Paul/0000-0002-8234-3730; NR 20 TC 39 Z9 41 U1 0 U2 0 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 SEP 20 PY 1999 VL 104 IS D17 BP 21443 EP 21454 DI 10.1029/97JD03299 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 238BC UT WOS:000082690200016 ER PT J AU Newell, RE Zhu, Y Connors, VS Reichle, HG Novelli, PC Gormsen, BB AF Newell, RE Zhu, Y Connors, VS Reichle, HG Novelli, PC Gormsen, BB TI Atmospheric processes influencing measured carbon monoxide in the NASA Measurement of Air Pollution From Satellites (MAPS) experiment SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID CHEMISTRY; APRIL; OZONE; CO AB The Measurement of Air Pollution From Satellites (MAPS) experiment measured global distributions of carbon monoxide (CO) while on board the space shuttle during April 9-19 and September 30 to October 11, 1994. This paper examines selected examples of the meteorological processes that contributed to the observed signals. We first examine and relate the mean distribution of MAPS-measured CO, surface station-measured CO, streamlines, and divergent winds averaged over the two missions. Tropical high CO values were associated with boundary layer convergence regions, particularly in October, that enable CO associated with biomass burning to reach the free troposphere where it can be detected by the nadir viewing gas filter 4.7 mu m radiometer. CO values over northern middle latitudes show evidence of fossil fuel pollution especially in April. Southern middle and high latitudes in April suggest photochemical control, while in October these regions are strongly influenced by the tropical biomass burning. Next, we consider events on 1 day near the center of each mission and show that in one of these cases, low CO measurements are associated with high potential vorticity, which suggests that the air samples originated from the stratosphere. Finally, we modify the two mean patterns, both within 23 days of the equinox, to illustrate the possible separation of the natural photochemical CO pattern from the CO pollution patterns. This procedure brings out the intercontinental and transcontinental transport of pollution in April northern hemisphere middle and high latitudes as well as, less markedly, in the October maps. It also accentuates the biomass burning contribution in October and shows pollution to extend southeastward from South America into the South Atlantic and also from Australia into the South Pacific. The separation is made possible by having CO measurements with global coverage. C1 MIT, Dept Earth Atmospher & Planetary Sci, Cambridge, MA 02139 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. NOAA, Climate Monitoring & Diagnost Lab, Boulder, CO 80303 USA. N Carolina State Univ, Dept Marine Earth & Atmospher Sci, Raleigh, NC 27695 USA. Sci Applicat Int Corp, Hampton, VA USA. RP Newell, RE (reprint author), MIT, Dept Earth Atmospher & Planetary Sci, Cambridge, MA 02139 USA. EM newell@newell1.mit.edu NR 22 TC 2 Z9 2 U1 0 U2 0 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 SEP 20 PY 1999 VL 104 IS D17 BP 21487 EP 21501 DI 10.1029/1999JD900394 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 238BC UT WOS:000082690200019 ER PT J AU Fan, SM Sarmiento, JL Gloor, M Pacala, SW AF Fan, SM Sarmiento, JL Gloor, M Pacala, SW TI On the use of regularization techniques in the inverse modeling of atmospheric carbon dioxide SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID SINGULAR-VALUE DECOMPOSITION; GENERAL-CIRCULATION MODEL; CO2; VARIABILITY; EMISSIONS; METHANE AB The global distribution of carbon sources and sinks is estimated from atmospheric CO2 measurements using an inverse method based on the Geophysical Fluid Dynamics Laboratory SKYHI atmospheric general circulation model. Applying the inverse model without any regularization yields unrealistically large CO2 fluxes in the tropical regions. We examine the use of three regularization techniques that are commonly used to stabilize inversions: truncated singular value decomposition, imposition of a priori flux estimates, and use of a quadratic inequality constraint. The regularization techniques can all be made to minimize the unrealistic fluxes in the tropical regions. This brings inversion estimated CO2 fluxes for oceanic regions in the tropics and in the Southern Hemisphere into better agreement with independent estimates of the air-sea exchange. However, one cannot assume that stabilized inversions give accurate estimates, as regularization merely holds the fluxes to a priori estimates or simply reduces them in magnitude in regions that are not resolvable by observations. By contrast, estimates of flux and uncertainty for the temperate North Atlantic, temperate North Pacific, and boreal and temperate North American regions are far less sensitive to the regularization parameters, consistent with the fact that these regions are better constrained by the present observations. C1 Princeton Univ, Atmospher & Ocean Sci Program, Princeton, NJ 08544 USA. Princeton Univ, Dept Ecol & Evolutionary Biol, Princeton, NJ 08544 USA. RP Fan, SM (reprint author), Princeton Univ, Atmospher & Ocean Sci Program, Sayre Hall,POB CN710, Princeton, NJ 08544 USA. EM fan@splash.princeton.edu 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 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD SEP 20 PY 1999 VL 104 IS D17 BP 21503 EP 21512 DI 10.1029/1999JD900215 PG 10 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 238BC UT WOS:000082690200020 ER PT J AU Bates, TS AF Bates, TS TI Special section: First Aerosol Characterization Experiment (ACE 1) part 2 - Preface SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Editorial Material ID MARINE BOUNDARY-LAYER; CAPE GRIM; SOUTHERN-OCEAN; MACQUARIE ISLAND; LAGRANGIAN-B; PARTICLES; TASMANIA; DIMETHYLSULFIDE; ATMOSPHERE; SEA C1 NOAA, Pacific Marine Environm Lab, Seattle, WA 98115 USA. RP Bates, TS (reprint author), NOAA, Pacific Marine Environm Lab, 7600 Sand Point Way Ne, Seattle, WA 98115 USA. RI Bates, Timothy/L-6080-2016 NR 26 TC 8 Z9 8 U1 1 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 SEP 20 PY 1999 VL 104 IS D17 BP 21645 EP 21647 DI 10.1029/1999JD900365 PG 3 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 238BC UT WOS:000082690200032 ER PT J AU Griffiths, FB Bates, TS Quinn, PK Clementson, LA Parslow, JS AF Griffiths, FB Bates, TS Quinn, PK Clementson, LA Parslow, JS TI Oceanographic context of the First Aerosol Characterization Experiment (ACE 1): A physical, chemical, and biological overview SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID MARINE BOUNDARY-LAYER; SOUTHERN-OCEAN; DIMETHYL-SULFIDE; PHYTOPLANKTON PRODUCTION; NEW-ZEALAND; SUBTROPICAL CONVERGENCE; AUSTRALASIAN SECTOR; STANDING STOCKS; WATER MASSES; SEA-WATER AB The First Aerosol Characterization Experiment (ACE 1) intensive experiment, conducted between November 14 and December 15, 1995, covered an oceanographically complex region, including the subtropical (ST), Subtropical Convergence Zone (STCZ), Subantarctic (SA), and polar water masses. Oceanographic and atmospheric sampling to identify the chemical and biological communities that might affect biologically produced, aerosol precursors in these water masses was carried out from the RV Discoverer and FRV Southern Surveyor. Sea surface temperature was not a good indicator of water mass during ACE 1. The physical structure east of 147.5(degrees)E was more complex than west of this longitude. Nutrient concentrations (nitrate, silicate) in the mixed layer increased, but ammonia concentrations decreased from ST to polar waters. Ammonia concentrations in surface waters exceeded > 5 mu M, and ammonia fluxes peaked at 12 mu M m(-2) d(-1) in ST water near Cape Grim between November 27 and 30. Seawater dimethyl sulfide (DMSsw) concentrations averaged 1.7 +/- 1.1 nM with maximum values near 6 nM in ST waters. The flux of dimethyl sulfide to the atmosphere averaged 4.7 +/- 5.0 mu M m(-2) d(-1), with peak fluxes (> 40 mu M m(-2) d(-1)) in SA water. DMSsw increased significantly only in SA waters during the experiment. Surface chlorophyll a concentrations measured from the FRV Southern Surveyor ranged between 0.3 and 0.6 mg m(-3). Surface chlorophyll-a concentrations along the Discoverer cruise track were similar, but 5 phytoplankton blooms (> 1 mg m(3)) were found. Integrated column chlorophylls ranged from 29.4 mg m(-2) in SA water to 53.2 mg m(-2) in ST water. Modeled primary production rates were ranged between 409 mg carbon m(-2) d(-1) in the polar front to 3180 mg carbon m(-2) d(-1) in ST water near Cape Grim. Mixed layer phytoplankton growth rates, estimated from net primary production, were 0.31 d(-1) in the SAF to 1.07 d(-1) in STCZ water east of Tasmania. Grazing dilution experiments showed microzooplankton grazing and phytoplankton growth rates were tightly coupled, with net growth rates ranging from - 0.13 d(-1) to 0.22 d(-1). During the ACE 1 intensive period, the surface waters were in transition from the deeply mixed, winter conditions to the shallowly stratified, spring conditions. The spring phytoplankton bloom was just beginning in the northern water masses, and isolated blooms were present at several locations in SA surface waters. The low standing stocks of chlorophyll and tightly coupled grazing rates may have been responsible for the low concentrations of DMS and NH3 in the region, and the generally low fluxes of these compounds to the atmosphere during the ACE 1 intensive experiment. C1 CSIRO, Marine Res, Castray Esplanade, Hobart, Tas 7000, Australia. NOAA, Pacific Marine Environm Lab, Seattle, WA 98115 USA. RP Griffiths, FB (reprint author), CSIRO, Marine Res, Castray Esplanade, Hobart, Tas 7000, Australia. EM Brian.Griffiths@marine.csiro.au RI Clementson, Lesley/M-6905-2013; Bates, Timothy/L-6080-2016; Quinn, Patricia/R-1493-2016 OI Quinn, Patricia/0000-0003-0337-4895 NR 77 TC 36 Z9 36 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 SEP 20 PY 1999 VL 104 IS D17 BP 21649 EP 21671 DI 10.1029/1999JD900386 PG 23 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 238BC UT WOS:000082690200033 ER PT J AU Weber, RJ McMurry, PH Bates, TS Clarke, AD Covert, DS Brechtel, FJ Kok, GL AF Weber, RJ McMurry, PH Bates, TS Clarke, AD Covert, DS Brechtel, FJ Kok, GL TI Intercomparison of airborne and surface-based measurements of condensation nuclei in the remote marine troposphere during ACE 1 SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID PASSING EFFICIENCY; AEROSOL; AIRCRAFT; DIAMETER; FLOW AB Intercomparisons of aerosol particle number concentrations measured with various condensation particle counters (CPCs) during the first Aerosol Characterization Experiment (ACE 1) are made to assess the accuracy of the airborne measurements. When no ambient 3-10 nm diameter particles (nanoparticles) were present, median concentrations' from four CPCs on the National Center for Atmospheric Research (NCAR) C-130 aircraft agreed to within similar to 6% and were highly correlated (r > 0.9). These instruments sampled from several different inlets and used various arrangements (e.g., tubing size and length, flow rates) to transport sampled air to the detectors. When the ambient aerosol contained significant numbers of nanoparticles, agreement between the CPCs deteriorated, Likely from differences in nanoparticle transmission and detection efficiencies. During these periods, average total number concentrations measured by two ultrafine CPCs varied on average by 60% with a correlation coefficient of 0.85. Intercomparisons of airborne and surface-based measurements were made during low-altitude flybys of surface measurement sites. During flybys, few nanoparticles were detected, and measured total condensation nuclei (CN) concentrations differed by roughly +5 to -20% (CNsurface/CNairborne-1) suggesting that the airborne measurements of fine aerosols agreed with ambient surface values to within 20%. Overall, we found that ambient fine particles (similar to 20-100 nm diameter) are fairly insensitive to airborne sampling techniques and thus are likely to be measured accurately. Sampling losses of smaller particles, however, may lead to a significant undermeasurement of ambient CN concentrations in rare instances when the number spectra are dominated by the smallest particles. This intercomparison involves measurements made in regions absent of liquid water to avoid artifact particles produced by fragmenting water droplets. C1 Brookhaven Natl Lab, Dept Appl Sci, Environm Chem Div, Upton, NY 11973 USA. Univ Minnesota, Dept Mech Engn, Particle Technol Lab, Minneapolis, MN 55455 USA. NOAA, Pacific Marine Environm Lab, Seattle, WA 98115 USA. Univ Hawaii, Sch Ocean & Earth Sci & Technol, Honolulu, HI 96822 USA. Univ Washington, Dept Atmospher Sci, Seattle, WA 98195 USA. Colorado State Univ, Dept Atmospher Sci, Ft Collins, CO 80523 USA. Natl Ctr Atmospher Res, Res Aviat Facil, Boulder, CO 80307 USA. RP Weber, RJ (reprint author), Georgia Inst Technol, Georgia Sch Earth & Atmospher Sci, Atlanta, GA 30332 USA. EM rweber@eas.gatech.edu RI McMurry, Peter/A-8245-2008; Bates, Timothy/L-6080-2016 OI McMurry, Peter/0000-0003-1609-5131; NR 20 TC 9 Z9 9 U1 0 U2 2 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 SEP 20 PY 1999 VL 104 IS D17 BP 21673 EP 21683 DI 10.1029/1998JD100103 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 238BC UT WOS:000082690200034 ER PT J AU Sievering, H Lerner, B Slavich, J Anderson, J Posfai, M Cainey, J AF Sievering, H Lerner, B Slavich, J Anderson, J Posfai, M Cainey, J TI O-3 oxidation of SO2 in sea-salt aerosol water: Size distribution of non-sea-salt sulfate during the First Aerosol Characterization Experiment (ACE 1) SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID MARINE BOUNDARY-LAYER; BURSTING BUBBLES; OZONE OXIDATION; CARBON-DIOXIDE; DRY DEPOSITION; NATURAL-WATERS; SULFUR; PARTICLES; SURFACE; MODEL AB Non sea-salt sulfate (NSS) of 2.2-2.3 nmol m(-3) total magnitude in aerosols observed during the First Aerosol Characterization Experiment (ACE-1) at Cape Grim, Tasmania, was trimodally distributed with similar to 1 nmol NSS m(-3) in > 0.7 mu m ambient diameter (diam) coarse seasalt mode aerosols; despite this low NSS concentration, [H2SO4(g)] was so low that < 1% of this NSS could have been due to H2SO4 scavenging. Ammonium was not associated with these coarse seasalt aerosols, suggesting that cloud processing was a minor contributor to the NSS found in > 0.7 mu m diam aerosols. The mechanism of O-3 oxidation of SO2 in sea-salt aerosol water (SSAW) is assessed for its capability to explain this coarse aerosol NSS. Limitation of this mechanism's NSS contribution is largely due to SSAW's buffering capacity since its reaction rate is reduced by 2 orders of magnitude at pH 6 versus the pH greater than or equal to 8 of unreacted SSAW. However, the buffering capacity of sea-salt aerosols may have been significantly enhanced over that of bulk seawater alkalinity. This appears to be due to carbonate resulting from small fragments of biogenic CaCO3 in the ocean's surface microlayer. Given the observed nonsoil calcium excess over that in bulk seawater, the estimated actual buffering capacity of sea-salt aerosols observed during ACE 1 was 50%, or more, enhanced over that due to bulk seawater alkalinity. Considering this enhanced buffering capacity, O-3 oxidation of SO2 in SSAW can produce sufficient NSS to explain 70-90% of the similar to 1 nmol m(-3) found in > 0.7 mu m diam coarse sea-salt aerosols with cloud processing and further oxidation of SO2 in SSAW (i.e., pH < 6) by other sea-salt conversion mechanisms contributing the remainder. The amount of NSS produced by sea-salt conversion mechanisms during the ACE 1 remote Southern Ocean experiment vied with homogeneous and cloud processing in their contribution to the total observed NSS of 2.2-2.3 nmol m(-3). C1 Univ Colorado, Dept Environm Sci & Geog, Denver, CO 80217 USA. Univ Colorado, Global Change & Environm Qual Program, Denver, CO 80217 USA. CSIRO, Aspendale, Vic, Australia. Arizona State Univ, Dept Geol & Chem, Tempe, AZ 85287 USA. NOAA, Climate Monitoring & Diagnost Lab, Aerosols Grp, Boulder, CO 80303 USA. RP Sievering, H (reprint author), Univ Colorado, Dept Environm Sci & Geog, POB 173364,CB 172, Denver, CO 80217 USA. EM hsieveri@carbon.cudenver.edu RI Posfai, Mihaly/C-1792-2012; Lerner, Brian/H-6556-2013 OI Posfai, Mihaly/0000-0001-9355-3533; Lerner, Brian/0000-0001-8721-8165 NR 55 TC 40 Z9 39 U1 2 U2 17 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 SEP 20 PY 1999 VL 104 IS D17 BP 21707 EP 21717 DI 10.1029/1998JD100086 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 238BC UT WOS:000082690200037 ER PT J AU Mari, C Suhre, K Rosset, R Bates, TS Huebert, BJ Bandy, AR Thornton, DC Businger, S AF Mari, C Suhre, K Rosset, R Bates, TS Huebert, BJ Bandy, AR Thornton, DC Businger, S TI One-dimensional modeling of sulfur species during the First Aerosol Characterization Experiment (ACE 1) Lagrangian B SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID MARINE BOUNDARY-LAYER; SEA-SALT AEROSOL; ATMOSPHERIC CHEMISTRY; DIMETHYL-SULFIDE; SENSITIVITY ANALYSIS; 3-DIMENSIONAL MODEL; OZONE OXIDATION; GAS-EXCHANGE; PARTICLES; MECHANISM AB A one-dimensional Lagrangian model is used to simulate vertical profiles and temporal evolution of dimethylsulfide (DMS), sulfur dioxide (SO2), aerosol methane sulfonate, and non-sea-salt sulfate (nss sulfate) that were measured during the three flights of the second First Aerosol Characterization Experiment (ACE 1) Lagrangian (Lagrangian B) experiment. Entrainment rate, mixing heights, and cloud occurrence are calculated prognostically in this type of model. The model is forced by geostrophic winds and large scale subsidence from European Centre for Medium-Range Weather Forecasts (ECMWF) analysis and sea surface temperature measured on board Research Weasel Discoverer. Gas phase oxidation and heterogeneous oxidation of SO2 to nss sulfate in clouds and sea-salt particles are considered. The evolution of dynamical variables in the column is found to be well reproduced by the model. The model captures 82% of the variance of observed DMS assuming OH is the only oxidant and a DMS flux term calculated from Liss and Merlivat [1986] parameterization and seawater DMS concentrations measured aboard RN Discoverer. However, uncertainties in DMS oxidation rates and regional seawater concentrations are too great to identify a best fit wind speed-transfer velocity relationship. SO2 mixing ratios are correctly represented in the model (least squares correlation coefficient r(2) = 75%) using a DMS to SO2 conversion efficiency of about 70%. Oxidation of SO2 in sea-salt particle appears to be a dominant process and controls SO2 lifetime during the Lagrangian B at least in the well mixed lower layer. Removing heterogeneous loss of SO2 in sea salt significantly deteriorates the simulation (r(2) = 50%). Under cloudy conditions, heterogeneous loss in cloud droplets and in sea-salt particles are competitive (relative rates are 35% and 41%, respectively, during flight 26). Model-generated aerosol methane sulfonate mixing ratios agree with the observations (r(2) = 62.5%) when high branching ratio for an addition oxidation pathway is used. The model estimates nss sulfate mixing ratios with little bias (median simulated-to-observed concentration ratio 1.03 and slope of the regression line 0.7) but captures only one third of the observed variance of nss sulfate. Part of the discrepancy could be due to the assumption of a decrease of nss sulfate mixing ratios with altitude in the model, whereas observations revealed high concentrations at 4500 m during the last two flights suggesting that horizontal transport could be more important than vertical mixing in this region. Nss sulfate is found to be produced photochemically under non cloudy, low wind speed conditions encountered during the first flight. During the last two flights, nss sulfate is produced mainly by oxidation in cloud droplets (48% during flight 25 and 69% during flight 26) and sea-salt particles (50% during flight 25 and 22% during flight 26). C1 Univ Toulouse 3, UMR 5560 CNRS, Lab Aerol, F-31400 Toulouse, France. NOAA, Pacific Marine Environm Lab, Seattle, WA 98115 USA. Univ Hawaii, Sch Ocean & Earth Sci & Technol, Dept Oceanog, Honolulu, HI 96822 USA. Drexel Univ, Dept Chem, Philadelphia, PA 19104 USA. Univ Hawaii Manoa, Dept Meteorol, Honolulu, HI 96822 USA. RP Mari, C (reprint author), Univ Toulouse 3, UMR 5560 CNRS, Lab Aerol, F-31400 Toulouse, France. EM marc@aero.obs-mip.fr RI Bates, Timothy/L-6080-2016; OI Suhre, Karsten/0000-0001-9638-3912 NR 66 TC 23 Z9 23 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 SEP 20 PY 1999 VL 104 IS D17 BP 21733 EP 21749 DI 10.1029/1999JD900022 PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 238BC UT WOS:000082690200039 ER PT J AU Wang, Q Suhre, K Krummel, P Siems, S Pan, LL Bates, TS Johnson, JE Lenschow, DH Heubert, BJ Kok, GL Schillawski, RD Prevot, ASH Businger, S AF Wang, Q Suhre, K Krummel, P Siems, S Pan, LL Bates, TS Johnson, JE Lenschow, DH Heubert, BJ Kok, GL Schillawski, RD Prevot, ASH Businger, S TI Characteristics of marine boundary layers during two Lagrangian measurement periods 1. General conditions and mean characteristics SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID CHARACTERIZATION EXPERIMENT ACE-1; STRATOCUMULUS; AEROSOL; TRANSITION; DYNAMICS; ASTEX AB Two sets of Lagrangian measurements were made during the southern Aerosol Characterization Experiment (ACE1) South of Tasmania, Australia, in December 1995. This paper intends to provide an overview of the general conditions encountered during the two intensive observational periods. The measurements by the NCAR C-130 provide the main data set for this study. We also use the sea surface temperature obtained from the R/V Discoverer and the European Centre for Medium-Range Weather Forecasts (ECMWF) analyses field for the large-scale divergence field. Emphases of the paper are on the atmospheric and oceanic environment and the: boundary layer mean structure during the six flights in the two Lagrangian measurement periods. The large scale features, such as variations of sea surface temperature, synoptic conditions, and large-scale velocity fields, are discussed. These large-scale environments had significant influences on boundary layer turbulence and the inversion structure. The boundary layer mean structure and its evolution along the Lagrangian trajectory are also studied using two-dimensional cross-section plots of vertical and horizontal (along the flight track) variation of potential temperature, water vapor, wind components, and ozone concentration. The most prominent feature of the boundary layer is the two-layered structure observed throughout Lagrangian B and during the last flight of Lagrangian A. The two layers have detectable differences in potential temperature, water vapor, and, to a lesser extent, ozone concentration. These differences make it necessary to study the exchange between the two layers. Low-level cloud structure and cloud microphysics are also discussed. We emphasize, though, that the results on cloud fractions should be used with caution due to the variable nature of the cloud bands observed during ACE1. C1 USN, Postgrad Sch, Dept Meteorol, Monterey, CA 93943 USA. UMR CNRS UPS 5560, Lab Aerol, F-31400 Toulouse, France. CSIRO, Div Atmospher Res, Aspendale, Vic 3195, Australia. Monash Univ, Dept Math, Clayton, Vic 3168, Australia. NOAA, Pacific Marine Environm Lab, Seattle, WA 98115 USA. Natl Ctr Atmospher Res, Mesoscale & Microscale Meteorol Div, Boulder, CO 80307 USA. Univ Hawaii, Dept Oceanog, Honolulu, HI 96826 USA. Natl Ctr Atmospher Res, Res Aviat Facil, Boulder, CO 80307 USA. RP Wang, Q (reprint author), USN, Postgrad Sch, Dept Meteorol, Monterey, CA 93943 USA. RI Prevot, Andre/C-6677-2008; Krummel, Paul/A-4293-2013; Siems, Steven/C-8339-2013; Bates, Timothy/L-6080-2016; OI Prevot, Andre/0000-0002-9243-8194; Krummel, Paul/0000-0002-4884-3678; Siems, Steven/0000-0002-8478-533X; LENSCHOW, DONALD/0000-0003-4353-0098; Suhre, Karsten/0000-0001-9638-3912 NR 10 TC 9 Z9 9 U1 0 U2 7 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD SEP 20 PY 1999 VL 104 IS D17 BP 21751 EP 21765 DI 10.1029/1998JD100099 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 238BC UT WOS:000082690200040 ER PT J AU Pszenny, AAP Prinn, RG Kleiman, G Shi, X Bates, TS AF Pszenny, AAP Prinn, RG Kleiman, G Shi, X Bates, TS TI Nonmethane hydrocarbons in surface waters, their sea-air fluxes and impact on OH in the marine boundary layer during the First Aerosol Characterization Experiment (ACE 1) SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID LIGHT-HYDROCARBONS; DIMETHYL-SULFIDE; CARBON-MONOXIDE; LAW CONSTANTS; SEAWATER; ATMOSPHERE; ATLANTIC; PACIFIC; PHYTOPLANKTON; CHEMISTRY AB Concentrations of six abundant alkanes (propane, 2-methylpropane, butane, 2-methylbutane, pentane, cyclopentane) and three abundant alkenes (2-methylpropene, cis-2-butene, 1,3-butadiene) were determined in air equilibrated with surface seawater in real time during the International Global Atmospheric Chemistry First Aerosol Characterization Experiment (ACE 1) campaign to the Southern Ocean in November-December 1995. Concentrations in ocean surface water inferred from these measurements generally lay within the ranges observed by other investigators at other times in other regions of the global ocean. Concentrations tended to decrease with increasing latitude. Comparison with a limited number of dissolved organic carbon (DOC) data obtained during transit from Hawaii to Hobart, Tasmania, suggested that higher hydrocarbon concentrations were associated with higher DOC levels. During the ACE 1 intensive study period west and south of Tasmania the differences in NMHC concentrations among the three major water masses sampled, while frequently significant, were not related in a simple direct or inverse way to surface water temperature, concentrations of nitrate, chlorophyll a, or dimethylsulfide, or to calculated sea-to-air transfer velocity or solar radiation intensity. The only correlations that showed some consistency within water masses were with temperature (negative) and nitrate (positive), an essential nutrient for phytoplankton growth. Deduced sea-to-air fluxes indicated modest open-ocean emissions of C-3-C-5 NMHC in this part of the global ocean. Assuming that the deduced fluxes were balanced by reaction with hydroxyl radical, OH, we estimated that the nine measured NMHC together accounted for negligible removal of OH compared to that due to the dominant OH + CO reaction and about 5 times less than that due to the DMS + OH reaction in the region of the marine boundary layer studied during ACE 1. C1 MIT, Ctr Global Change Sci, Cambridge, MA 02139 USA. NOAA, Pacific Marine Environm Lab, Ocean Climate Res Div, Seattle, WA 98115 USA. RP Pszenny, AAP (reprint author), MIT, Ctr Global Change Sci, Room 54-1312, Cambridge, MA 02139 USA. EM pszenny@mit.edu; rprinn@mit.edu; gary@jake.mit.edu; bates@pmel.noaa.gov RI Bates, Timothy/L-6080-2016 NR 50 TC 8 Z9 11 U1 2 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 SEP 20 PY 1999 VL 104 IS D17 BP 21785 EP 21801 DI 10.1029/1999JD900114 PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 238BC UT WOS:000082690200042 ER PT J AU Blake, NJ Blake, DR Wingenter, OW Sive, BC Kang, CH Thornton, DC Bandy, AR Atlas, E Flocke, F Harris, JM Rowland, FS AF Blake, NJ Blake, DR Wingenter, OW Sive, BC Kang, CH Thornton, DC Bandy, AR Atlas, E Flocke, F Harris, JM Rowland, FS TI Aircraft measurements of the latitudinal, vertical, and seasonal variations of NMHCs, methyl nitrate, methyl halides, and DMS during the First Aerosol Characterization Experiment (ACE 1) SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID ALKYL NITRATE; PHOTOCHEMICAL PRODUCTION; TROPOSPHERIC OZONE; AIR; IODIDE; ATLANTIC; HYDROCARBONS; HALOCARBONS; TRANSPORT; PACIFIC AB Canister sampling for the determination of atmospheric mixing ratios of nonmethane hydrocarbons (NMHCs), selected halocarbons, and methyl nitrate was conducted aboard the National Center for Atmospheric Research (NCAR) C-130 aircraft over the Pacific and Southern Oceans as part of the First Aerosol Characterization Experiment (ACE 1) during November and December 1995. A latitudinal profile, flown from 76 degrees N to 60 degrees S, revealed latitudinal gradients for most trace gases. NMHC and halocarbon gases with predominantly anthropogenic sources, including ethane, ethyne, and tetrachloroethene, exhibited significantly higher mixing ratios in the northern hemisphere at all altitudes. Methyl chloride exhibited its lowest mixing ratios at the highest northern hemisphere latitudes, and the distributions of methyl nitrate and methyl iodide were consistent with tropical and subtropical oceanic sources. Layers containing continental air characteristic of aged biomass burning emissions were observed above about 3 km over the remote southern Pacific and near New Zealand between approximately 19 degrees S and 43 degrees S. These plumes originated from the west, possibly from fires in southern Africa. The month-long intensive investigation of the clean marine southern midlatitude troposphere south of Australia revealed decreases in the mixing ratios of ethane, ethyne, propane, and tetrachloroethene, consistent with their seasonal mixing ratio cycle. By contrast, increases in the average marine boundary layer concentrations of methyl iodide, methyl nitrate, and dimethyl sulfide (DMS) were observed as the season progressed to summer conditions. These increases were most appreciable in the region south of 44 degrees S over Southern Ocean waters characterized as subantarctic and polar, indicating a seasonal increase in oceanic productivity for these gases. C1 Univ Calif Irvine, Dept Chem, Irvine, CA 92697 USA. Jeju Natl Univ, Dept Chem, Cheju 690756, South Korea. Drexel Univ, Dept Chem, Philadelphia, PA 19104 USA. Natl Ctr Atmospher Res, Div Atmospher Chem, Boulder, CO 80307 USA. NOAA, Climate Monitoring & Diagnost Lab, Boulder, CO 80303 USA. RP Blake, NJ (reprint author), Univ Calif Irvine, Dept Chem, Irvine, CA 92697 USA. EM nblake@uci.edu; drblake@uci.edu; oliver@eas.gatech.edu; sive@lasp.colorado.edu; changhee@cheju.cheju.ac.kr; dct@ac2.chemistry.drexel.edu; arb@acl.chemistry.drexel.edu; atlas@acd.ucar.edu; ffl@acd.ucar.edu; harris@cmdl3.cmdl.noaa.gov; rowland@uci.edu RI Atlas, Elliot/J-8171-2015 NR 71 TC 66 Z9 67 U1 0 U2 15 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 SEP 20 PY 1999 VL 104 IS D17 BP 21803 EP 21817 DI 10.1029/1999JD900238 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 238BC UT WOS:000082690200043 ER PT J AU Wong-Ng, W Melamud, M Bennett, LH Watson, RE AF Wong-Ng, W Melamud, M Bennett, LH Watson, RE TI Local environments of three forms of Ba2YCu3O6+x SO PHYSICA C LA English DT Article DE Wigner-Seitz cells; bonding; superconductor ID HARD MAGNETS; SUPERCONDUCTOR; TC; YBA2CU3O7-DELTA; DISCLINATIONS; ANISOTROPIES; PRESSURE; PACKING; PHASES AB The Wigner-Seitz local atomic cell construction procedure, provides a topological means for comparing series of related structures in terms of the number and type of nearest neighbors. We used this construction to further our understanding of the chemical bonding environment (and hence, the superconducting properties) in three structurally related materials, Ba2YCu3O6+x (x = 1, 1/2, and 0). These are high-T-c superconductors of T-c approximate to 92 K, 56 K, and a nonsuperconductor, respectively. The local environment around Y is found to be similar in all three compounds, and the topology around Ba is generally similar to that in the ideal perovskite. The Cu sites in the Cu-O plane in all three materials show similar anisotropic bonding behavior. Significant results are: (i) that Ba contributes to the bonding with Cu sites, and (ii) the most noticeable difference in the local environment in these compounds is around the Cu sites in the Cu-O "chains". We propose a modified charge-transfer model, involving the Cu-O "chains", "planes" and Ba as an electronic unit, to correlate structure with the observed superconducting properties. The bonding behavior of these oxides also appears to be different from the conventional metal alloy superconductors. (C) 1999 Elsevier Science B.V, All rights reserved. C1 US Dept Commerce, Mat Sci & Engn Lab, Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Brookhaven Natl Lab, Upton, NY 11973 USA. Nucl Res Ctr Negev, IL-84190 Beer Sheva, Israel. RP Wong-Ng, W (reprint author), US Dept Commerce, Mat Sci & Engn Lab, Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NR 34 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD SEP 20 PY 1999 VL 322 IS 3-4 BP 177 EP 185 DI 10.1016/S0921-4534(99)00399-8 PG 9 WC Physics, Applied SC Physics GA 247FL UT WOS:000083210400006 ER PT J AU Holland, M AF Holland, M TI Comment on "Unraveling quantum dissipation in the frequency domain" - Reply SO PHYSICAL REVIEW LETTERS LA English DT Article C1 Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. Natl Inst Stand & Technol, Boulder, CO 80309 USA. RP Holland, M (reprint author), Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. NR 1 TC 1 Z9 1 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 SEP 20 PY 1999 VL 83 IS 12 BP 2470 EP 2470 DI 10.1103/PhysRevLett.83.2470 PG 1 WC Physics, Multidisciplinary SC Physics GA 237MX UT WOS:000082661100049 ER PT J AU Lupton, JE Baker, ET Massoth, GJ AF Lupton, JE Baker, ET Massoth, GJ TI Helium, heat, and the generation of hydrothermal event plumes at mid-ocean ridges SO EARTH AND PLANETARY SCIENCE LETTERS LA English DT Article DE geothermal systems; plumes; mid-ocean ridges; He-3; heat flow; Juan de Fuca Ridge ID DE-FUCA-RIDGE; FLOOR ERUPTION SITE; 1993 COAXIAL EVENT; EAST PACIFIC RISE; HE-3/HEAT RATIOS; DIKE INJECTION; JUAN; SYSTEMS; HE-3; MEGAPLUMES AB Hydrothermal event plumes are unique water-column features observed over mid-ocean ridges, presumably generated by the sudden release of large volumes of hot, buoyant fluid. Although the specifics of event plume generation are unknown, event plumes have been attributed to the rapid emptying of a hydrothermal reservoir or to rapid heat extraction from a recently emplaced dike or seafloor lava flows. The chemical and thermal signatures of event plumes as compared to the underlying steady-state plumes offer important clues to the generation of event plumes. Event plumes have low He-3/heat ratios of similar to 0.4 x 10(-17) mol J(-1), similar to vent fluids from mature hydrothermal systems. In contrast, the steady-state plumes found beneath the event plumes have elevated and variable He-3/heat ratios of 2 to 5 x 10(-17) mol J(-1) Fluids collected directly over fresh lava flows have even higher He-3/heat ratios of 2 to 8 x 10(-17) mol J(-1), up to 30 times the event plume values. These disparate He-3/heat ratios place strong constraints on models of event plume generation, especially models which rely on heat extraction from seafloor eruptions. Published by Elsevier Science B.V. C1 NOAA, Pacific Marine Environm Lab, Hatfield Marine Sci Ctr, Newport, OR 97365 USA. NOAA, Pacific Marine Environm Lab, Seattle, WA 98115 USA. RP Lupton, JE (reprint author), NOAA, Pacific Marine Environm Lab, Hatfield Marine Sci Ctr, Newport, OR 97365 USA. NR 47 TC 36 Z9 40 U1 1 U2 9 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0012-821X J9 EARTH PLANET SC LETT JI Earth Planet. Sci. Lett. PD SEP 15 PY 1999 VL 171 IS 3 BP 343 EP 350 DI 10.1016/S0012-821X(99)00149-1 PG 8 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 232MH UT WOS:000082374200005 ER PT J AU Kim, JS AF Kim, JS TI A matrix formalism for the Hall effect in multicarrier semiconductor systems SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID FIELD-DEPENDENT HALL; ELECTRICAL CHARACTERIZATION; LIGHT HOLES; MOBILITIES; DENSITIES; FILMS; MAGNETORESISTANCE; CONDUCTION; HEAVY AB A matrix formalism for the Hall effect is presented for an arbitrary J-fold multicarrier semiconductor system. Explicit formulas are derived for important transport quantities such as the sheet resistance, the Hall coefficient, and the Hall scattering factor. For J less than or equal to 3, these formulas reduce to simple closed-form expressions as a function of the applied magnetic field and the carrier densities and mobilities. The closed-form formulas are useful for the correct interpretation of the Hall effect in multicarrier semiconductor systems. The field dependence and asymptotic behavior of these formulas are also discussed. [S0021-8979(99)07118-2]. C1 Natl Inst Stand & Technol, Div Semicond Elect, Gaithersburg, MD 20899 USA. RP Kim, JS (reprint author), Natl Inst Stand & Technol, Div Semicond Elect, Gaithersburg, MD 20899 USA. NR 17 TC 16 Z9 16 U1 2 U2 6 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD SEP 15 PY 1999 VL 86 IS 6 BP 3187 EP 3194 DI 10.1063/1.371187 PG 8 WC Physics, Applied SC Physics GA 230BU UT WOS:000082232400039 ER PT J AU Ishikawa, K Takagi, S Chow, LC Suzuki, K AF Ishikawa, K Takagi, S Chow, LC Suzuki, K TI Reaction of calcium phosphate cements with different amounts of tetracalcium phosphate and dicalcium phosphate anhydrous SO JOURNAL OF BIOMEDICAL MATERIALS RESEARCH LA English DT Article DE calcium phosphate cement; hydroxyapatite; hydroxyapatite cement; self-setting cement; biomaterial; tetracalcium phosphate; dicalcium phosphate anhydrous ID HYDROXYAPATITE CEMENT; SETTING BEHAVIOR; TISSUE-RESPONSE AB Calcium phosphate cements (CPCs) with different amounts of tetracalcium phosphate (TTCP) and dicalcium phosphate anhydrous (DCPA) (TTCP/DCPA molar ratio from 0.25 to 2.00) were prepared to further understand the setting reaction and the factors that could influence the properties of CPCs. Quantitative X-ray diffraction patterns, Fourier transform IR spectra, and diametral tensile strength of the set mass were measured along with pH measurements of the CPC suspension. Calcium-deficient hydroxyapatite (d-HAP) with a calcium to phosphate molar ratio of approximately 1.5 was formed initially in the CPC setting consisting of an equimolar mixture of TTCP and DCPA. This gradually transformed into stoichiometric KA (s-HA) with increasing incubation time. The s-HA was formed in the initial stage when the CPC contained an excess amount of TTCP. In contrast, maturation to s-HAP was slow when the CPC contained excess amounts of DCPA. The highest mechanical strength of set CPC was associated with an equimolar mixture of TTCP and DCPA, and the mechanical strength decreased as the TTCP/DCPA molar ratio deviated from 1.00. We concluded, therefore, that the setting reaction and the nature of the resulting set mass are dependent on the molar ratios of TTCP and DCPA. (C) 1999 John Wiley & Sons, Inc.*. C1 Okayama Univ, Sch Dent, Dept Biomat, Okayama 7008525, Japan. NIST, Amer Dent Assoc Hlth Fdn, Paffenbarger Res Ctr, Gaithersburg, MD 20899 USA. RP Ishikawa, K (reprint author), Okayama Univ, Sch Dent, Dept Biomat, 2-5-1 Shikata, Okayama 7008525, Japan. FU NIDCR NIH HHS [DE11789] NR 27 TC 54 Z9 56 U1 0 U2 6 PU JOHN WILEY & SONS INC PI NEW YORK PA 605 THIRD AVE, NEW YORK, NY 10158-0012 USA SN 0021-9304 J9 J BIOMED MATER RES JI J. Biomed. Mater. Res. PD SEP 15 PY 1999 VL 46 IS 4 BP 504 EP 510 DI 10.1002/(SICI)1097-4636(19990915)46:4<504::AID-JBM8>3.0.CO;2-H PG 7 WC Engineering, Biomedical; Materials Science, Biomaterials SC Engineering; Materials Science GA 213WE UT WOS:000081295600008 PM 10398011 ER PT J AU Hochlaf, M Leonard, C Ferguson, EE Rosmus, P Reinsch, EA Carter, S Handy, NC AF Hochlaf, M Leonard, C Ferguson, EE Rosmus, P Reinsch, EA Carter, S Handy, NC TI Potential energy function and vibrational states of N2CO+ SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID IONS; GAS; ASSOCIATION; ACETYLENE; OPERATORS; MOLECULES; FIELD; BOND; CO+; N-2 AB A six-dimensional potential energy function (PEF) for the electronic ground state of N2CO+ (X (2)A(')) has been generated by electronic structure calculations using the restricted open shell coupled cluster RCCSD(T) approach. The ion has a planar trans equilibrium structure with: R-NN=1.106 Angstrom, R-NC=1.905 Angstrom, R-CO=1.127 Angstrom, theta(NNC)=175.3 degrees, and theta(NCO)=129.1 degrees. Variational calculations of the vibrational states (J=0) have yielded the following anharmonic wavenumbers for the fundamentals: nu(1) (NN stretch) 2287.2, nu(2) (CO stretch) 2071.0, nu(3) (CN stretch+NCO bend) 546.9, nu(4) (CN stretch+NCO bend) 215.2, nu(5) (in-plane NNC bend) 123.4, nu(6) (out-of-plane NNC bend) 133.8 (all values are in cm(-1)). For fixed equilibrium coordinates except one, the barriers to linearity have been calculated to be 8 cm(-1) for the NNC and 2260 cm(-1) for the NCO moieties, the torsional barrier to be 35 cm(-1). It has been found that the nu(3) and nu(4) modes are strongly coupled, the in-plane nu(5) and out-of-plane nu(6) bending modes possess an inverse anharmonicity and fall into clusters. Using complete active space self-consitent-field CASSCF approach on the collinear cuts of the PEF for low-lying excited states several conical intersections between the (2)Pi and the (2)Sigma(+) states have been located. (C) 1999 American Institute of Physics. [S0021- 9606(99)30135-5]. C1 Univ Marne la Vallee, Theoret Chem Grp, F-77454 Champs Sur Marne, France. Univ Frankfurt, Fachbereich Chem, D-60439 Frankfurt, Germany. Univ Cambridge, Dept Chem, Cambridge CB2 1EW, England. NOAA, Climate Monitoring & Diagnost Lab, Boulder, CO 80303 USA. RP Hochlaf, M (reprint author), Univ Marne la Vallee, Theoret Chem Grp, F-77454 Champs Sur Marne, France. OI LEONARD, Celine/0000-0003-0303-3505 NR 28 TC 27 Z9 27 U1 1 U2 4 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD SEP 15 PY 1999 VL 111 IS 11 BP 4948 EP 4955 DI 10.1063/1.479754 PG 8 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 233AB UT WOS:000082402400012 ER PT J AU Garzoli, SL Richardson, PL Duncombe Rae, CM Fratantoni, DM Goni, GJ Roubicek, AJ AF Garzoli, SL Richardson, PL Duncombe Rae, CM Fratantoni, DM Goni, GJ Roubicek, AJ TI Three Agulhas rings observed during the Benguela Current experiment SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID SOUTHEAST ATLANTIC-OCEAN; RETROFLECTION; EDDIES; THERMOCLINE; CIRCULATION; FLUXES; WATER AB A field program to study the circulation of the Benguela Current and its extension into the southeastern Atlantic Ocean has completed the survey and instrument deployment phase. We report here new observations of three Agulhas rings north and west of Cape Town, South Africa. Three mesoscale anticyclonic rings initially identified by means of TOPEX/POSEIDON altimetry were surveyed with expendable bathythermographs, conductivity-temperature-depth-oxygen profiles, direct current measurements from a lowered acoustic Doppler current profiler, a hull-mounted acoustic Doppler current profiler, and satellite-tracked surface drifters. Characteristics of the rings are presented, and their origins are discussed. Two are typical Agulhas rings surveyed at different times after their generation; the third Agulhas ring has an anomalous water mass structure whose most likely origin is the Subtropical Front. C1 NOAA, Atlantic Oceanog & Meteorol Lab, Miami, FL 33149 USA. Woods Hole Oceanog Inst, Woods Hole, MA 02543 USA. Sea Fisheries Res Inst, ZA-8012 Cape Town, South Africa. RP Garzoli, SL (reprint author), NOAA, Atlantic Oceanog & Meteorol Lab, 4301 Rickenbacher Causeway, Miami, FL 33149 USA. EM garzoli@aoml.noaa.gov RI Garzoli, Silvia/A-3556-2010; Fratantoni, David/C-7121-2011; Goni, Gustavo/D-2017-2012 OI Garzoli, Silvia/0000-0003-3553-2253; Goni, Gustavo/0000-0001-7093-3170 NR 28 TC 45 Z9 45 U1 0 U2 4 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 SEP 15 PY 1999 VL 104 IS C9 BP 20971 EP 20985 DI 10.1029/1999JC900060 PG 15 WC Oceanography SC Oceanography GA 251YD UT WOS:000083473200032 ER PT J AU Musselman, SG Santosusso, TM Barnes, JD Sperling, LH AF Musselman, SG Santosusso, TM Barnes, JD Sperling, LH TI Domain structure and interphase dimensions in poly(urethaneurea) elastomers using DSC and SAXS SO JOURNAL OF POLYMER SCIENCE PART B-POLYMER PHYSICS LA English DT Article DE small-angle scattering; differential scanning calorimetry; microstructure; urethaneurea; elastomer ID ANGLE X-RAY; POLYURETHANE BLOCK COPOLYMERS; MULTIPLE ENDOTHERMIC BEHAVIOR; MICROPHASE SEPARATION; MICRODOMAIN STRUCTURE; SCATTERING; MORPHOLOGY; BLENDS AB Small-angle X-ray scattering (SAXS) and differential scattering calorimetry (DSC) were used to demonstrate distinct differences in domain size, phase separation, and hydrogen bonding in a series of segmented urethaneurea elastomers prepared from isocyanate-terminated prepolymers and aromatic diamine chain extenders. Two types of prepolymers were studied. The first contained a broadly polydisperse high molecular mass oligomer with relatively high levels of free isocyanate monomer. The second type of prepolymer contained low levels of high molecular mass oligomers with mass fractions greater than 90% of the two-to-one adduct of toluene diisocyanate (TDI) to polytetramethylene glycol (PTMEG). The mass fraction of the residual unreacted diisocyanate was less than 0.1% in the second type. Two chain extenders, 4,4'-methylene bis-(2-chloroaniline)(Mboca) and 4,4'-methylene bis-(3-chloro-2,6-diethylaniline) (MCDEA), were used to convert the prepolymers to poly(urethaneurea) elastomers. Materials prepared from the prepolymers with low oligomer polydispersity exhibited smaller hard segment domains with more ordered morphology, greater phase separation, and more hydrogen bonding than those prepared from prepolymers with high oligomer polydispersity. These tendencies were enhanced in those elastomers prepared by chain extension with MCDEA compared to those made with Mboca. (C) 1999 John Wiley & Sons, Inc. C1 NIST, Polymer Struct & Mech Grp, Gaithersburg, MD 20899 USA. Air Prod & Chem Inc, Allentown, PA 18195 USA. Lehigh Univ, Bethlehem, PA 18015 USA. RP Barnes, JD (reprint author), NIST, Polymer Struct & Mech Grp, Gaithersburg, MD 20899 USA. RI He, Yong/F-8752-2012 NR 41 TC 19 Z9 20 U1 2 U2 3 PU JOHN WILEY & SONS INC PI NEW YORK PA 605 THIRD AVE, NEW YORK, NY 10158-0012 USA SN 0887-6266 J9 J POLYM SCI POL PHYS JI J. Polym. Sci. Pt. B-Polym. Phys. PD SEP 15 PY 1999 VL 37 IS 18 BP 2586 EP 2600 DI 10.1002/(SICI)1099-0488(19990915)37:18<2586::AID-POLB4>3.0.CO;2-A PG 15 WC Polymer Science SC Polymer Science GA 231XF UT WOS:000082336100004 ER PT J AU Kautz, RL Keller, MW Martinis, JM AF Kautz, RL Keller, MW Martinis, JM TI Leakage and counting errors in a seven-junction electron pump SO PHYSICAL REVIEW B LA English DT Article ID CURRENT STANDARDS; TUNNEL-JUNCTIONS; ACCURACY; CHARGE AB Leakage and counting errors are explored experimentally in a well-characterized seven-junction electron pump and compared with predictions of the orthodox theory, including cotunneling. Theory and experiment are in good agreement at intermediate temperatures, where errors are dominated by thermally activated, single-junction processes. At low temperatures, however, the observed errors far exceed predictions, indicating that the orthodox theory omits an important error process. C1 Natl Inst Stand & Technol, Boulder, CO 80303 USA. RP Kautz, RL (reprint author), Natl Inst Stand & Technol, 325 Broadway, Boulder, CO 80303 USA. NR 23 TC 28 Z9 28 U1 0 U2 1 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD SEP 15 PY 1999 VL 60 IS 11 BP 8199 EP 8212 DI 10.1103/PhysRevB.60.8199 PG 14 WC Physics, Condensed Matter SC Physics GA 244VC UT WOS:000083070600085 ER PT J AU Drohat, AC Jagadeesh, J Ferguson, E Stivers, JT AF Drohat, AC Jagadeesh, J Ferguson, E Stivers, JT TI Role of electrophilic and general base catalysis in the mechanism of Escherichia coli uracil DNA glycosylase SO BIOCHEMISTRY LA English DT Article ID CRITHIDIA-FASCICULATA; AMP NUCLEOSIDASE; STRUCTURAL BASIS; EXCISION-REPAIR; KINETICS; SPECIFICITY; HYDROLYSIS; ACID AB Escherichia coli uracil DNA glycosylase (UDG) catalyzes the hydrolysis of premutagenic uracil bases in DNA by flipping the deoxyuridine from the DNA helix [Stivers, J. T., et al. (1999) Biochemistry 38, 952]. A general acid-base mechanism has been proposed whereby His187 facilitates leaving group departure by protonating the O2 of uracil and Asp64 activates a water molecule for nucleophilic attack at Cl' of the deoxyribose. Detailed kinetic studies on the H187Q, H187A, and D64N mutant enzymes indicate that Asp64 and His187 stabilize the chemical transition state by 5.3 and 4.8 kcal/mol, respectively, with little effect on substrate or product binding. The pH dependence of k(cat) for wild-type and H187Q UDG indicates that an unprotonated group in the enzyme-substrate complex (pK(a) = 6.2 +/- 0.2) is required for catalysis. This unprotonated group has a small Delta H of ionization (-0.4 +/- 1.7 kcal/mol) and is absent in the pH profile for D64N UDG, suggesting that it corresponds to the general base Asp64. The pH dependence of k(cat) for wild-type, H187Q, and D64N UDG shows no evidence for an essential protonated group over the pH range of 5.5-10. Hence, the pK(a) of His187 must be outside this pH range if-it serves as an electrophilic catalyst. These results support a mechanism in which Asp64 serves as the general base and His187 acts as a neutral electrophile, stabilizing a developing negative charge on uracil O2 in the transition state. In the following paper of this issue we establish by crystallography and heteronuclear NMR spectroscopy that the imidazole of His 187 is neutral during the catalytic cycle of UDG. C1 Univ Maryland, Inst Biotechnol, Ctr Adv Res Biotechnol, Rockville, MD 20850 USA. Natl Inst Stand & Technol, Rockville, MD 20850 USA. RP Stivers, JT (reprint author), Univ Maryland, Inst Biotechnol, Ctr Adv Res Biotechnol, 9600 Gudelsky Dr, Rockville, MD 20850 USA. FU NIGMS NIH HHS [R01 GM056834, GM56834] NR 31 TC 93 Z9 93 U1 0 U2 9 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0006-2960 J9 BIOCHEMISTRY-US JI Biochemistry PD SEP 14 PY 1999 VL 38 IS 37 BP 11866 EP 11875 DI 10.1021/bi9910878 PG 10 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 240PR UT WOS:000082834800002 PM 10508389 ER PT J AU Drohat, AC Xiao, GY Tordova, M Jagadeesh, J Pankiewicz, KW Watanabe, KA Gilliland, GL Stivers, JT AF Drohat, AC Xiao, GY Tordova, M Jagadeesh, J Pankiewicz, KW Watanabe, KA Gilliland, GL Stivers, JT TI Heteronuclear NMR and crystallographic studies of wild-type and H187Q Escherichia coli uracil DNA glycosylase: Electrophilic catalysis of uracil expulsion by a neutral histidine 187 SO BIOCHEMISTRY LA English DT Article ID NUCLEAR MAGNETIC-RESONANCE; BASE-EXCISION-REPAIR; ENZYMATIC CATALYSIS; ACTIVE-SITE; TRIOSEPHOSPHATE ISOMERASE; STRUCTURAL BASIS; HYDROGEN-BOND; MECHANISM; SPECTRA; STATE AB The nature of the putative general acid His187 in the reaction catalyzed by Escherichia coli uracil DNA glycosylase (UDG) was investigated using X-ray crystallography and NMR spectroscopy. The crystal structures of H187Q UDG, and its complex with uracil, have been solved at 1.40 and 1.60 Angstrom resolution, respectively. The structures are essentially identical to those of the wild-type enzyme, except that the side chain of Gln187 is turned away from the uracil base and cannot interact with uracil O2. This result provides a structural basis for the similar kinetic properties of the H187Q and H187A enzymes. The ionization state of His187 was directly addressed with H-1-N-15 NMR experiments optimized for histidine ring spin systems, which established that His 187 is neutral in the catalytically active state of the enzyme (pK(a) <5.5). These NMR experiments also show that His187 is held in the N-epsilon 2-H tautomeric form, consistent with the crystallographic observation of a 2.9 Angstrom hydrogen bond from the backbone nitrogen of Ser189 to the ring N-delta 1 of His187. The energetic cost of breaking this hydrogen bond may contribute significantly to the low pK(a) of His 187. Thus, the traditional view that a cationic His 187 donates a proton to uracil O2 is incorrect. Rather, we propose a concerted mechanism involving general base catalysis by Asp64 and electrophilic stabilization of the developing enolate on uracil O2 by a neutral His187. C1 Univ Maryland, Maryland Biotechnol Inst, Ctr Adv Res Biotechnol, Rockville, MD 20850 USA. Natl Inst Stand & Technol, Rockville, MD 20850 USA. Pharmasset Inc, Atlanta, GA 30345 USA. RP Stivers, JT (reprint author), Univ Maryland, Maryland Biotechnol Inst, Ctr Adv Res Biotechnol, 9600 Gudelsky Dr, Rockville, MD 20850 USA. FU NIGMS NIH HHS [R01 GM056834, GM56834] NR 47 TC 67 Z9 67 U1 0 U2 5 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0006-2960 J9 BIOCHEMISTRY-US JI Biochemistry PD SEP 14 PY 1999 VL 38 IS 37 BP 11876 EP 11886 DI 10.1021/bi9910880 PG 11 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 240PR UT WOS:000082834800003 PM 10508390 ER PT J AU Li, L Ruzgas, T Gaigalas, AK AF Li, L Ruzgas, T Gaigalas, AK TI Fluorescence from Alexa 488 fluorophore immobilized on a modified gold electrode SO LANGMUIR LA English DT Article ID REDUCTIVE DESORPTION; ALKANETHIOL MONOLAYERS; ENERGY-TRANSFER; METAL-SURFACES; AU(111); ADSORPTION; INTERFACE AB The fluorescence intensity was measured from Alexa 488 fluorophore immobilized on a modified polycrystalline gold electrode. In the range of potentials -0.5 to +0.2 V vs Ag(Ag/Cl), the fluorescence signal was small and of the order expected from known fluorescence quenching by metal surfaces. Immobilization of Alexa 488 with a larger separation between the fluorophore and the electrode surface resulted in an increased fluorescence signal in the potential range mentioned above. For potentials more negative than -0.5 V and more positive than +0.2 V, the fluorescence signal increased exponentially. The increase was attributed to a potential driven increase in the separation between the fluorophore and the electrode surface brought about by reorientation and dechemisorption of the fluorophore. For potentials more positive than -0.7 V vs Ag(Ag/Cl) the change in fluorescence intensity was quasi-reversible, for potentials more negative than -0.8 V the change was irreversible, and the fluorescence vanished on returning to more positive potentials. The dependence of the fluorescence intensity on potential was interpreted in terms of sequential occurrence of reorientation (E > -0.7 V) and dechemisorption (E < -0.8 V). The fluorescence signal yields significant additional information about the behavior of molecules at electrode surfaces. C1 NIST, Div Biotechnol, Gaithersburg, MD 20899 USA. RP Gaigalas, AK (reprint author), NIST, Div Biotechnol, 100 Bur Dr,Stop 8312, Gaithersburg, MD 20899 USA. RI Ruzgas, Tautgirdas/C-4646-2008 NR 16 TC 14 Z9 14 U1 1 U2 7 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0743-7463 J9 LANGMUIR JI Langmuir PD SEP 14 PY 1999 VL 15 IS 19 BP 6358 EP 6363 PG 6 WC Chemistry, Multidisciplinary; Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA 236RY UT WOS:000082618800032 ER PT J AU Lehmann, KK Northby, JA AF Lehmann, KK Northby, JA TI Potential of an ionic impurity in a large He-4 cluster SO MOLECULAR PHYSICS LA English DT Article ID ELECTRON SURFACE-STATES; HELIUM CLUSTERS; LIQUID-HELIUM AB This paper presents an analysis of the motion of an impurity ion in a nanometre scale He-4 cluster. Due to induction forces, ions are strongly localized near the centre of the cluster, with a root mean squared thermal displacement of only a few Angstrom. The trapping potential is found to be nearly harmonic, with a frequency of 2.3(1.0) GHz for a positive (negative) ion in a He cluster of radius 5 nm. The anharmonicity is small and positive (energy increases slightly faster than linear with quantum number). It is suggested that by using frequency sweep microwave radiation, it should be possible to drive the ion centre-of-mass motion up to high quantum numbers, allowing the study of the critical velocity as a function of cluster size. C1 Natl Inst Stand & Technol, Boulder, CO 80309 USA. Univ Rhode Isl, Dept Phys, Kingston, RI 02881 USA. Princeton Univ, Dept Chem, Princeton, NJ 08544 USA. Univ Colorado, JILA, Boulder, CO 80309 USA. RP Lehmann, KK (reprint author), Univ Colorado, JILA, Boulder, CO 80309 USA. NR 34 TC 31 Z9 31 U1 0 U2 4 PU TAYLOR & FRANCIS LTD PI LONDON PA ONE GUNPOWDER SQUARE, LONDON EC4A 3DE, ENGLAND SN 0026-8976 J9 MOL PHYS JI Mol. Phys. PD SEP 10 PY 1999 VL 97 IS 5 BP 639 EP 644 PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 233YC UT WOS:000082453900004 ER PT J AU Lehmann, KK AF Lehmann, KK TI Potential of a neutral impurity in a large He-4 cluster SO MOLECULAR PHYSICS LA English DT Article ID HELIUM CLUSTERS; MONTE-CARLO; SPECTROSCOPY; STATES; DROPLETS; ATOMS AB This paper presents an analysis of the motion of a neutral impurity species in a nanometre scale He-4 cluster, extending a previous study of the dynamics of an ionic impurity. It is shown that for realistic neutral impurity-He potentials, such as those of SF6 and OCS, the impurity is kept well away from the surface of the cluster by long range induction and dispersion interactions with He, but that a large number of 'particle in a box' centre-of-mass states are thermally populated. It is explicitly demonstrated how to calculate the spectrum that arises from the coupling of the impurity rotation and the centre-of-mass motion, and it is found that this is a potentially significant source of inhomogeneous broadening in vibration-rotation spectra of anisotropic impurities. Another source of inhomogeneous broadening is the hydro-dynamic coupling of the rotation of the impurity with the centre-of-mass velocity. A quantum hamiltonian to describe this effect is derived from the classical hydrodynamic kinetic energy of an ellipsoid. Simple analytic expressions are derived for the resulting spectral line shape for an impurity in bulk He, and the relevant matrix elements derived to allow fully quantum calculations of the coupling of the centre-of-mass motion and rotation for an impurity confined in a spherical He cluster. Lastly, the hydrodynamic contribution to the impurity effective moment of inertia is evaluated and found to produce only a minor fractional increase. C1 Univ Colorado, JILA, Boulder, CO 80309 USA. Natl Inst Stand & Technol, Boulder, CO 80309 USA. Princeton Univ, Dept Chem, Princeton, NJ 08544 USA. RP Lehmann, KK (reprint author), Univ Colorado, JILA, Boulder, CO 80309 USA. NR 40 TC 93 Z9 93 U1 0 U2 6 PU TAYLOR & FRANCIS LTD PI LONDON PA ONE GUNPOWDER SQUARE, LONDON EC4A 3DE, ENGLAND SN 0026-8976 J9 MOL PHYS JI Mol. Phys. PD SEP 10 PY 1999 VL 97 IS 5 BP 645 EP 666 DI 10.1080/002689799163497 PG 22 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 233YC UT WOS:000082453900005 ER PT J AU DeMarco, B Jin, DS AF DeMarco, B Jin, DS TI Onset of Fermi degeneracy in a trapped atomic gas SO SCIENCE LA English DT Article ID BOSE-EINSTEIN CONDENSATION; HARMONIC TRAP; MAGNETIC TRAP; SUPERFLUIDITY; TEMPERATURE; SCATTERING AB An evaporative cooling strategy that uses a two-component Fermi gas was employed to cool a magnetically trapped gas of 7 X 10(5) K-40 atoms to 0.5 of the Fermi temperature T-F. In this temperature regime, where the state occupation at the Lowest energies has increased from essentially zero at high temperatures to nearly 60 percent, quantum degeneracy was observed as a barrier to evaporative cooling and as a modification of the thermodynamics. Measurements of the momentum distribution and the total energy of the confined Fermi gas directly revealed the quantum statistics. C1 Univ Colorado, Natl Inst Stand & Technol, Quantum Phys Div, Boulder, CO 80309 USA. Natl Inst Stand & Technol, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. Univ Colorado, Dept Phys, Boulder, CO 80309 USA. RP Jin, DS (reprint author), Univ Colorado, Natl Inst Stand & Technol, Quantum Phys Div, Boulder, CO 80309 USA. OI DeMarco, Brian/0000-0002-2791-0413 NR 34 TC 842 Z9 853 U1 5 U2 31 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 SEP 10 PY 1999 VL 285 IS 5434 BP 1703 EP 1706 DI 10.1126/science.285.5434.1703 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 234EY UT WOS:000082472600026 PM 10481000 ER PT J AU Keller, MW Eichenberger, AL Martinis, JM Zimmerman, NM AF Keller, MW Eichenberger, AL Martinis, JM Zimmerman, NM TI A capacitance standard based on counting electrons SO SCIENCE LA English DT Article ID PUMP AB A capacitance standard based directly on the definition of capacitance was built. Single-electron tunneling devices were used to place N electrons of charge e onto a cryogenic capacitor C, and the resulting voltage change Delta V was measured. Repeated measurements of C = Ne/Delta V with this method have a relative standard deviation of 0.3 X 10(-6). This standard offers a natural basis for capacitance analogous to the Josephson effect for voltage and the quantum Hall effect for resistance. C1 Natl Inst Stand & Technol, Boulder, CO 80303 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Keller, MW (reprint author), Natl Inst Stand & Technol, 325 Broadway, Boulder, CO 80303 USA. RI Eichenberger, Ali/J-3073-2012 NR 12 TC 162 Z9 164 U1 1 U2 7 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 SEP 10 PY 1999 VL 285 IS 5434 BP 1706 EP 1709 DI 10.1126/science.285.5434.1706 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 234EY UT WOS:000082472600027 ER PT J AU Basak, D Boettinger, WJ Josell, D Coriell, SR McClure, JL Krishnan, S Cezairliyan, A AF Basak, D Boettinger, WJ Josell, D Coriell, SR McClure, JL Krishnan, S Cezairliyan, A TI Effect of heating rate and grain size on the melting behavior of the alloy Nb-47 mass% Ti in pulse-heating experiments SO ACTA MATERIALIA LA English DT Article DE alloy; high temperature; diffusion; melting ID RADIANCE TEMPERATURES; SOLIDIFICATION; NIOBIUM; EMISSIVITY; MOLYBDENUM; TRANSIENT AB The effect of heating rate and grain size on the melting behavior of Nb-47 mass% Ti is measured and modeled. The experimental method uses rapid resistive self-heating of wire specimens at rates between similar to 10(2) and similar to 10(4) K/s and simultaneous measurement of radiance temperature and normal spectral emissivity as functions of time until specimen collapse, typically between 0.4 and 0.9 fraction melted. During heating, a sharp drop in emissivity is observed at a temperature that is independent of heating rare and grain size. This drop is due to surface and grain boundary melting at the alloy solidus temperature even though there is very little deflection (limited melting) of the temperature-time curve from the imposed heating rate. Above the solidus temperature, the emissivity remains nearly constant with increasing temperature and the temperature vs lime curve gradually reaches a sloped plateau over which the major fraction of the specimen melts. As the heating rate and/or grain size is increased, the onset temperature of the sloped plateau approaches the alloy liquidus temperature and the slope of the plateau approaches zero. This interpretation of the shapes of the temperature-time curves is supported by a model that includes diffusion in the solid coupled with a heat balance during the melting process. There is no evidence of loss of local equilibrium at the melt front during melting in these experiments. (C) 1999 Published by Elsevier Science Ltd on behalf of Acta Metallurgica Inc. All rights reserved. C1 Natl Inst Stand & Technol, Div Met, Gaithersburg, MD 20899 USA. Containerless Res, Evanston, IL 60201 USA. RP Boettinger, WJ (reprint author), Natl Inst Stand & Technol, Div Met, Gaithersburg, MD 20899 USA. NR 24 TC 21 Z9 21 U1 0 U2 4 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 SEP 8 PY 1999 VL 47 IS 11 BP 3147 EP 3158 DI 10.1016/S1359-6454(99)00191-3 PG 12 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 237ZQ UT WOS:000082686800003 ER PT J AU Rappaz, M Boettinger, WJ AF Rappaz, M Boettinger, WJ TI On dendritic solidification of multicomponent alloys with unequal liquid diffusion coefficients SO ACTA MATERIALIA LA English DT Article DE theory and modelling; diffusion; multicomponent dendritic growth ID GROWTH; MICROSEGREGATION; MICROSTRUCTURES; MODEL AB A model has been developed previously by Rappaz and Thevoz (Acta metall., 1987, 35, 1478; 1987, 35, 2929) for the solidification of binary alloys having an equiaxed dendritic morphology. The extension of this model to multicomponent alloys is straightforward if the diffusion coefficients in the liquid of the various solute elements are equal. When they are different however, it becomes necessary to distinguish the concentrations at the dendrite tip position. governing the growth kinetics, from the average concentrations within the interdendritic liquid region. A model is presented which couples the dendrite growth kinetics with an overall solute balance performed at the scale of the grain. The diffusion profile outside the grain envelope is calculated using a Landau transformation and an implicit scheme. The calculated solidification paths during and after recalescence are compared with the Scheil approximation for various conditions. Additionally, a model predicting the secondary dendrite arm spacing in multicomponent alloys is briefly described. (C) 1999 Acta Metallurgica Inc. Published by Elsevier Science Ltd. All rights reserved. C1 Ecole Polytech Fed Lausanne, MXG, Met Phys Lab, CH-1015 Lausanne, Switzerland. Natl Inst Stand & Technol, Div Met, Gaithersburg, MD 20899 USA. RP Rappaz, M (reprint author), Ecole Polytech Fed Lausanne, MXG, Met Phys Lab, CH-1015 Lausanne, Switzerland. NR 24 TC 90 Z9 96 U1 2 U2 25 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 SEP 8 PY 1999 VL 47 IS 11 BP 3205 EP 3219 DI 10.1016/S1359-6454(99)00188-3 PG 15 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 237ZQ UT WOS:000082686800008 ER PT J AU Thompson, WE Jacox, ME AF Thompson, WE Jacox, ME TI The vibrational spectra of CO2+, (CO2)(2)(+), CO2-, and (CO2)(2)(-) trapped in solid neon SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID CARBON-DIOXIDE ACTIVATION; ATMOSPHERIC POSITIVE-IONS; DIODE-LASER ABSORPTION; ELECTRON-AFFINITIES; INFRARED-SPECTRA; MATRIX-ISOLATION; PHOTOELECTRON-SPECTROSCOPY; AB-INITIO; CLUSTERS; PHOTODISSOCIATION AB When a Ne:CO2 mixture is subjected to Penning ionization and/or photoionization by neon atoms in their first excited states, between 16.6 and 16.85 eV, and the products are rapidly frozen at approximately 5 K, the infrared spectrum of the resulting deposit includes absorptions assigned to CO2+, (CO2)(2)(+), CO2-, and (CO2)(2)(-). The lowest (mu (2)Sigma(u)(+)) Renner component of the bending fundamental of CO2+ trapped in a neon matrix appears near the gas-phase band center, but other Renner components are undetectable. Absorptions of a photolabile product correspond to the recently identified CO-stretching fundamentals of (CO2)(2)(+). Weak infrared absorptions at 1253.8 and 714.2 cm(-1) are assigned to nu(1) and nu(2) of CO2-, respectively, and a moderately intense absorption at 2894.7 cm(-1) is assigned to the nu(1)+nu(3) combination band of that product. As in other recent argon- and neon-matrix studies, two weak infrared absorptions can be assigned to the two infrared-active OCO-stretching fundamentals of the D-2d structure of (CO2)(2)(-). Detailed isotopic substitution studies support all of these assignments. A weak absorption near the CO2 bending fundamental, for which isotopic substitution data are incomplete, may be contributed either by a second fundamental of (CO2)(2)(-) (D-2d) with b(2) symmetry or by a weakly interacting (CO2)(n).. CO2- complex. Such ion-molecule complexes contribute other absorptions near nu(3) of CO2 and of CO2-. (C) 1999 American Institute of Physics. [S0021-9606(99)00934-4]. C1 NIST, Div Opt Technol, Gaithersburg, MD 20899 USA. RP Thompson, WE (reprint author), NIST, Div Opt Technol, Gaithersburg, MD 20899 USA. EM marilyn.jacox@nist.gov NR 42 TC 50 Z9 50 U1 0 U2 24 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 SEP 8 PY 1999 VL 111 IS 10 BP 4487 EP 4496 DI 10.1063/1.479212 PG 10 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 229YC UT WOS:000082222500016 ER PT J AU Nisato, G Ivkov, R Amis, EJ AF Nisato, G Ivkov, R Amis, EJ TI Structure of charged dendrimer solutions as seen by small-angle neutron scattering SO MACROMOLECULES LA English DT Article ID PROTEIN INTERACTIONS; MOLECULES; LIGHT AB We present results of small-angle neutron scattering (SANS) investigations into the characteristics of charged poly(amidoamine) (PAMAM) dendrimer solutions in deuterium oxide. The study shows that ionic strength, surface charge density, and concentration are the crucial parameters controlling the degree of structural organization of the solution. Upon the addition of acid, HCl, we observe a peak in the scattering intensity. The results indicate that increasing ionization of terminal amines results in interparticle interactions giving rise to local, liquidlike ordering. These interactions can be screened by adding monovalent salt (NaCl) in large quantities. The short-range interactions were studied by systematically varying dendrimer and salt concentration (up to 2 M). Contrary to most weak polyelectrolyte systems, we did not observe a negative second virial coefficient, even for the highest salt concentrations. C1 Natl Inst Stand & Technol, Div Polymers, Gaithersburg, MD 20899 USA. RP Amis, EJ (reprint author), Natl Inst Stand & Technol, Div Polymers, 100 Bur Dr Stop 8542, Gaithersburg, MD 20899 USA. RI Ivkov, Robert/A-3902-2015 OI Ivkov, Robert/0000-0002-2930-5276 NR 23 TC 54 Z9 56 U1 0 U2 7 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0024-9297 J9 MACROMOLECULES JI Macromolecules PD SEP 7 PY 1999 VL 32 IS 18 BP 5895 EP 5900 DI 10.1021/ma990631h PG 6 WC Polymer Science SC Polymer Science GA 235AF UT WOS:000082516000025 ER PT J AU Karim, A Douglas, JF Nisato, G Liu, DW Amis, EJ AF Karim, A Douglas, JF Nisato, G Liu, DW Amis, EJ TI Transient target patterns in phase separating filled polymer blends SO MACROMOLECULES LA English DT Article ID DIRECTED SPINODAL DECOMPOSITION; FILMS; MIXTURES; KINETICS AB Recent simulations suggest that the presence of filler particles in a phase separating blend can induce the development of composition waves having the symmetry of the filler particles. We investigate these predictions through atomic force microscopy (AFM) measurements on ultrathin (L approximate to 100 nm) polystyrene and poly(vinyl methyl ether) blend films containing a low concentration of model filler particles (silica particles having a nominal diameter approximate to 100 nm). The filled blend films were spun-cast on acid-cleaned silica wafers, and phase separation was induced by a temperature jump into the two-phase region (T approximate to 145 degrees C) of the bulk polymer blend. By rinsing off the polymer film with solvent, we show that the silica particles are associated with the substrate so that the filler particles represent a quenched disorder perturbation of the film phase separation. The presence of the filler particles leads to the development of circular composition waves ("target patterns") about the filler particles during the intermediate stage of phase separation. These target patterns disintegrate as the background spinodal phase separation pattern becomes much larger than the filler particles. Our observations are consistent with idealized two-dimensional Cahn-Hilliard-Cook simulations of the phase separation of polymer blends having a small concentration of filler particles. C1 NIST, Div Polymers, Gaithersburg, MD 20899 USA. RP Karim, A (reprint author), NIST, Div Polymers, Gaithersburg, MD 20899 USA. NR 29 TC 45 Z9 46 U1 0 U2 7 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0024-9297 J9 MACROMOLECULES JI Macromolecules PD SEP 7 PY 1999 VL 32 IS 18 BP 5917 EP 5924 DI 10.1021/ma990439f PG 8 WC Polymer Science SC Polymer Science GA 235AF UT WOS:000082516000029 ER PT J AU Williams, PA AF Williams, PA TI Modulation phase-shift measurement of PMD using only four launched polarisation states: a new algorithm SO ELECTRONICS LETTERS LA English DT Article AB A new algorithm is presented for measuring differential group delay in optical fibres and components using the modulation phase-shift technique which only requires the launching of four polarisation slates. This significantly improves the previous technique that requires polarisation scanning. Experimental results demonstrate good agreement between these two methods. C1 Natl Inst Stand & Technol, Boulder, CO 80309 USA. RP Williams, PA (reprint author), Natl Inst Stand & Technol, 325 Broadway, Boulder, CO 80309 USA. NR 2 TC 22 Z9 21 U1 0 U2 0 PU IEE-INST ELEC ENG PI HERTFORD PA MICHAEL FARADAY HOUSE SIX HILLS WAY STEVENAGE, HERTFORD SG1 2AY, ENGLAND SN 0013-5194 J9 ELECTRON LETT JI Electron. Lett. PD SEP 2 PY 1999 VL 35 IS 18 BP 1578 EP 1579 DI 10.1049/el:19991068 PG 2 WC Engineering, Electrical & Electronic SC Engineering GA 240AM UT WOS:000082803500056 ER PT J AU El-Bahy, A Kunnath, S Stone, W Taylor, A AF El-Bahy, A Kunnath, S Stone, W Taylor, A TI Cumulative seismic damage of circular bridge columns: Variable amplitude tests SO ACI STRUCTURAL JOURNAL LA English DT Article DE bridges (structures); cyclic loads; damage; ductility AB The findings from an experimental study to investigate cumulative seismic damage in reinforced concrete circular bridge piers is presented. Twelve identical quarter-scale bridge columns, designed in accordance with current AASHTO specifications, were fabricated and tested to failure. Results from Phase I testing, which included constant amplitude tests to determine the low-cycle fatigue characteristics of the bridge column, were presented in a companion paper. This paper summarizes results of variable amplitude testing that focused on the effects of load pth on cumulative damage. The imposed displacement histories were obtained form analytical simulations of the model column subjected to a sequence of earthquakes of varying duration and magnitude. Test observations indicate that failure is generally initiated by confinement inadequacy and the rupture of the transverse spiral reinforcement. The tests also demonstrated the potential for low-cycle fatigue fracture of the main longitudinal steel when the specimen was subjected to relatively larger displacement amplitudes, typically in excess of 4 percent lateral drift. A fatigue-based damage model, derived from the constant-amplitude tests completed in Phase I testing, was applied to the observed response of the six specimens tested in this phase. Findings from the study indicate that the energy capacity of members is ductility-dependent and that fatigue-based damage models offer a reliable means of assessing seismic structural performance. C1 Tilden Lobnitz Cooper, Orlando, FL USA. Univ Cent Florida, Orlando, FL 32816 USA. Natl Inst Stand & Technol, Construct Metrol & Automat Grp, Gaithersburg, MD 20899 USA. KPFF Consulting Engineers, Seattle, WA USA. RP El-Bahy, A (reprint author), Tilden Lobnitz Cooper, Orlando, FL USA. NR 6 TC 29 Z9 31 U1 0 U2 1 PU AMER CONCRETE INST PI FARMINGTON HILLS PA 38800 INTERNATIONAL WAY, COUNTRY CLUB DRIVE, PO BOX 9094, FARMINGTON HILLS, MI 48333-9094 USA SN 0889-3241 J9 ACI STRUCT J JI ACI Struct. J. PD SEP-OCT PY 1999 VL 96 IS 5 BP 711 EP 719 PG 9 WC Construction & Building Technology; Engineering, Civil; Materials Science, Multidisciplinary SC Construction & Building Technology; Engineering; Materials Science GA 291WM UT WOS:000085762300005 ER PT J AU Gilman, JW AF Gilman, JW TI Flammability and thermal stability studies of polymer layered-silicate (clay) nanocomposites SO APPLIED CLAY SCIENCE LA English DT Article DE montmorillonite; nanocomposites; flammability; polymers ID NYLON 6-CLAY HYBRID AB In the pursuit of improved approaches to fire retarding polymers, a wide variety of concerns must be addressed in addition to the flammability issues. For commodity polymers, their low cost requires that the fire retardant (FR) approach also be of low cost. This Limits solutions primarily to additive type approaches. These additives must be inexpensive and easily processed with the polymer. In addition, the additive must not excessively degrade the other performance properties of the polymer, and it must not create environmental problems when recycling or at the time of its final disposal. We have recently found that polymer layered-silicate (clay) nanocomposites have the unique combination of reduced flammability and improved physical properties. This paper is intended as an overview of the research to date, by our group and others, on the use of clays, dispersed at the nanometer level, in polymers for improving thermal stability and flammability. (C) 1999 Published by Elsevier Science B.V. C1 Natl Inst Stand & Technol, Mat Fire Res Grp, Gaithersburg, MD 20899 USA. NR 21 TC 1264 Z9 1312 U1 13 U2 110 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0169-1317 J9 APPL CLAY SCI JI Appl. Clay Sci. PD SEP PY 1999 VL 15 IS 1-2 BP 31 EP 49 DI 10.1016/S0169-1317(99)00019-8 PG 19 WC Chemistry, Physical; Materials Science, Multidisciplinary; Mineralogy SC Chemistry; Materials Science; Mineralogy GA 229TW UT WOS:000082212700004 ER PT J AU Krishnamurthi, A Leto, G Linsky, JL AF Krishnamurthi, A Leto, G Linsky, JL TI A search for radio emission at the bottom of the main sequence and beyond SO ASTRONOMICAL JOURNAL LA English DT Article DE stars : activity; stars : low-mass, brown dwarfs; stars : magnetic fields ID BROWN DWARF; STARS; CORONAE; END AB We have used the VLA to conduct a deep search for 3.6 cm radio emission from nearby very low mass stars and brown dwarfs. The Gudel-Benz relation is used to predict radio luminosities for some very low mass stars and candidate brown dwarfs with measured X-ray fluxes. The predicted radio fluxes are quite small, whereas the measured radio flux from the brown dwarf candidate GY 31 in the rho Oph cloud is relatively strong. In light of our new observations, this object remains an anomaly. We present upper limits for our measured radio fluxes at 3.6 cm for our targets. C1 Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. Natl Inst Stand & Technol, Boulder, CO 80309 USA. RP Krishnamurthi, A (reprint author), Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. RI Leto, Giuseppe/N-3355-2015 OI Leto, Giuseppe/0000-0002-0040-5011 NR 25 TC 18 Z9 18 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-6256 J9 ASTRON J JI Astron. J. PD SEP PY 1999 VL 118 IS 3 BP 1369 EP 1372 DI 10.1086/301015 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 241ZR UT WOS:000082914200022 ER PT J AU Barnston, AG Leetmaa, A Kousky, VE Livezey, RE O'Lenic, EA Van den Dool, H Wagner, AJ Unger, DA AF Barnston, AG Leetmaa, A Kousky, VE Livezey, RE O'Lenic, EA Van den Dool, H Wagner, AJ Unger, DA TI NCEP forecasts of the El Nino of 1997-98 and its US impacts SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article ID SEA-SURFACE TEMPERATURE; QUANTIFYING SOUTHERN OSCILLATION; CANONICAL CORRELATION-ANALYSIS; OCEAN-ATMOSPHERE MODEL; PRECIPITATION RELATIONSHIPS; NORTHERN-HEMISPHERE; COUPLED MODEL; PACIFIC SST; PREDICTION; ENSO AB The strong El Nino of 1997-98 provided a unique opportunity for National Weather Service, National Centers for Environmental Prediction, Climate Prediction Center (CPC) forecasters to apply several years of accumulated new knowledge of the U.S, impacts of El Nino to their long-lead seasonal forecasts with more clarity and confidence than ever previously. This paper examines the performance of CPC' s official forecasts, and its individual component forecast tools, during this event. Heavy winter precipitation across California and the southern plains-Gulf coast region was accurately forecast with at least six months of lead time. Dryness was also correctly forecast in Montana and in the southwestern Ohio Valley. The warmth across the northern half of the country was correctly forecast, but extended farther south and east than predicted. As the winter approached, forecaster confidence in the forecast pattern increased, and the probability anomalies that were assigned reached unprecedented levels in the months immediately preceding the winter. Verification scores for winter 1997/98 forecasts set a new record at CPC for precipitation. Forecasts for the autumn preceding the El Nino winter were less skillful than those of winter, but skill for temperature was still higher than the average expected for autumn. The precipitation forecasts for autumn showed little skill. Forecasts for the spring following the El Nino were poor, as an unexpected circulation pattern emerged, giving the southern and southeastern United States a significant drought. This pattern, which differed from the historical Fl Nino pattern for spring, may have been related to a large pool of anomalously warm water that remained in the far eastern tropical Pacific through summer 1998 while the waters in the central Pacific cooled as the Fl Nino was replaced by a La Nina by the first week of June. It is suggested that in addition to the obvious effects of the 1997-98 El Nino on 3-month mean climate in the United States, the El Nino (indeed, any strong El Nino or La Nina) may have provided a positive influence on the skill of medium-range forecasts of 5-day mean climate anomalies. This would reflect first the connection between the mean seasonal conditions and the individual contributing synoptic events, but also the possibly unexpected effect of the tropical boundary forcing unique to a given synoptic event. Circumstantial evidence suggests that the skill of medium-range forecasts is increased during lead times (and averaging periods) long enough that the boundary conditions have a noticeable effect, but not so long that the skin associated with the initial conditions disappears. Firmer evidence of a beneficial influence of ENSO on subclimate-scale forecast skill is needed, as the higher skill may be associated just with the higher amplitude of the forecasts, regardless of the reason for that amplitude. C1 NOAA, Natl Ctr Environm Predict, Climate Predict Ctr, Camp Springs, MD 20746 USA. RP Barnston, AG (reprint author), NOAA, Natl Ctr Environm Predict, Climate Predict Ctr, World Weather Bldg,Room 604,5200 Auth Rd,W-NP51, Camp Springs, MD 20746 USA. NR 53 TC 69 Z9 69 U1 0 U2 5 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 SEP PY 1999 VL 80 IS 9 BP 1829 EP 1852 DI 10.1175/1520-0477(1999)080<1829:NFOTEN>2.0.CO;2 PG 24 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 232RK UT WOS:000082383600002 ER PT J AU Ibarra, H Wolf, R Meyer, J Mlodzik, J AF Ibarra, H Wolf, R Meyer, J Mlodzik, J TI DataStreme: Weather education from the AMS to the classroom SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article AB The American Meteorological Society's DataStreme Project is a Society effort to educate K-12 teachers in meteorology. The course utilizes a combination of printed material, Web-based information, and real-time meteorological data in a distance learning format. Learning is facilitated by a Local Implementation Team (LIT). The following paper discusses the program from the perspective of the eastern Iowa LIT. C1 Natl Weather Serv, NOAA, Davenport, IA 52806 USA. W Branch Middle Sch, W Branch, IA USA. KCRG TV, Cedar Rapids, IA USA. RP Wolf, R (reprint author), Natl Weather Serv, NOAA, 9050 Harrison St, Davenport, IA 52806 USA. NR 1 TC 2 Z9 2 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 SEP PY 1999 VL 80 IS 9 BP 1901 EP 1905 DI 10.1175/1520-0477(1999)080<1901:DWEFTA>2.0.CO;2 PG 5 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 232RK UT WOS:000082383600007 ER PT J AU Blevins, LG Renfro, MW Lyle, KH Laurendeau, NM Gore, JP AF Blevins, LG Renfro, MW Lyle, KH Laurendeau, NM Gore, JP TI Experimental study of temperature and CH radical location in partially premixed CH4/air coflow flames SO COMBUSTION AND FLAME LA English DT Article ID LASER-INDUCED FLUORESCENCE; TURBULENT JET FLAMES; DIFFUSION FLAMES; LAMINAR; COMBUSTION; EXTINCTION; NO; PYROMETRY; EMISSION; DYNAMICS AB As part of an ongoing investigation of an exhaust NOx emission index minimum measured for partially premixed flames, radial temperature profiles and CH radical locations were measured in atmospheric-pressure, partially premixed, coflow, methane/air flames with fuel-side equivalence ratios of 1.6, 2.0, and 3.5, at three axial heights above the burner. The work was undertaken because of the importance of temperature and CH radical behavior in NO formation chemistry. Thin-filament pyrometry was found to be more appropriate than thermocouple thermometry for temperature measurements in partially premixed flames. Results demonstrated that the 1.6-equivalence-ratio flame exhibited classical double-flame structure, the 2.0-ecluivalence-ratio flame was a merged flame, and the 3.5-equivalence-ratio flame exhibited diffusion-flame structure. Signals from CH* chemiluminescence and CH laser-induced fluorescence provide evidence that, for the present measurement locations, double flames exhibit single CH peaks which can be associated with their premixed component flames. Double CH radical peaks, which were predicted to occur in low-strain-rate flames, were not found for the limited number of flame conditions and locations studied. In the near-burner region, the premixed and nonpremixed component flames of the Phi(B) = 1.6 double flame diverge radially with increasing downstream distance and merge together for larger values of Phi(B). (C) 1999 by The Combustion Institute. C1 Purdue Univ, Sch Mech Engn, W Lafayette, IN 47907 USA. RP Blevins, LG (reprint author), Natl Inst Stand & Technol, Bldg & Fire Res Lab, Gaithersburg, MD 20899 USA. NR 59 TC 42 Z9 42 U1 1 U2 10 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 USA SN 0010-2180 J9 COMBUST FLAME JI Combust. Flame PD SEP PY 1999 VL 118 IS 4 BP 684 EP 696 DI 10.1016/S0010-2180(99)00023-1 PG 13 WC Thermodynamics; Energy & Fuels; Engineering, Multidisciplinary; Engineering, Chemical; Engineering, Mechanical SC Thermodynamics; Energy & Fuels; Engineering GA 219UN UT WOS:000081625600011 ER PT J AU Boyer, T Conkright, ME Levitus, S AF Boyer, T Conkright, ME Levitus, S TI Seasonal variability of dissolved oxygen, percent oxygen saturation, and apparent oxygen utilization in the Atlantic and Pacific Oceans SO DEEP-SEA RESEARCH PART I-OCEANOGRAPHIC RESEARCH PAPERS LA English DT Article ID GLOBAL CARBON-CYCLE; WORLD OCEAN; ATMOSPHERIC OXYGEN; NORTH PACIFIC; GAS-EXCHANGE; HEAT-STORAGE; SEA; SEAWATER; BUBBLES; RESPIRATION AB Using objectively analyzed seasonal fields of dissolved oxygen content, percent oxygen saturation, and apparent oxygen utilization (AOU), we describe the large-scale seasonal variability of oxygen for the Atlantic and Pacific Oceans in the upper 400 m. The winter minus summer basin zonal averages of AOU reveal a two-layer feature in both the Atlantic and the Pacific, for both hemispheres. Biological activity and seasonal stratification in the summer give the upper 50-75 m of the water column in each basin a lower AOU in summer than winter. Greater mixing of upper ocean waters in winter gives the 75-400 m layer lower AOU values in that season. The basin integral seasonal volumes of oxygen for both the North Atlantic and the North Pacific mirror what is occurring in the atmosphere, indicating that there is a seasonal flux of oxygen across the air-sea interface. Winter total O-2 volume in the ocean is above the annual mean; the summer volume is below. Larger seasonal differences in the total O-2 content are observed in the North Atlantic Ocean than the North Pacific Ocean. A seasonal net outgassing (SNO) of 8.3 x 10(14) moles O-2 is calculated from basin means, which is 25% higher than previous results. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 NOAA, Ocean Climate Lab, Natl Oceanog Data Ctr, Silver Spring, MD 20910 USA. RP NOAA, Ocean Climate Lab, Natl Oceanog Data Ctr, E-OC5,1315 East West Highway, Silver Spring, MD 20910 USA. EM tboyer@nodc.noaa.gov NR 39 TC 16 Z9 18 U1 1 U2 15 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0967-0637 EI 1879-0119 J9 DEEP-SEA RES PT I JI Deep-Sea Res. Part I-Oceanogr. Res. Pap. PD SEP PY 1999 VL 46 IS 9 BP 1593 EP 1613 DI 10.1016/S0967-0637(99)00021-7 PG 21 WC Oceanography SC Oceanography GA 223LZ UT WOS:000081843700005 ER PT J AU Scherrer, SS Kelly, JR Quinn, GD Xu, K AF Scherrer, SS Kelly, JR Quinn, GD Xu, K TI Fracture toughness (K-Ic) of a dental porcelain determined by fractographic analysis SO DENTAL MATERIALS LA English DT Article DE toughness; K-Ic; porcelain; ceramic; fractography; slow crack growth; indentation; surface crack in flexure; indentation strength; indentation fracture ID SURFACE CRACK; CERAMICS AB Objectives: Fractographic analysis of indentation cracks is performed following flexure testing as pare of the ASTM (1999) standard for fracture toughness, K-Ic, determination in advanced ceramics. This method depends on the conduciveness of the material towards fractographic interpretation. The purpose of this study was to evaluate the use of fractography in fracture toughness methods with a feldspathic dental porcelain, in which K-Ic was measured fractographically as well as numerically using two controlled-flaw beam bending techniques. Methods: The following methods for K-Ic determination were applied to a dental porcelain containing a leucite volume fraction of 15-20%: (1) surface crack in flexure (SCF) (dependent upon fractographic analysis); and (2) indentation strength (IS) at indentation loads of 9.8 and 19.6 N (applying both standard numeric calculations and fractographic analysis). The testing environments were (1) ambient air (IS and SCF) and (2) flowing dry nitrogen (SCF). Results: No significant differences were found between numeric and fractographic K-Ic values for the IS technique at both indentation loads (9.8 and 19.6 N) in ambient air, although K-Ic values were sensitive to indentation load. Due to the presence of residual stresses, stable crack extension was observed fractographically in all IS specimens, as evidenced by differences between initial (a(initial)) and critical (a(critical)) crack dimensions. For the SCF method, there was a significant difference in toughness between specimens tested in air versus dry nitrogen, however no fractographic evidence for chemically assisted slow crack growth (SCG) was observed. Significance: The SCF method as described by the ASTM standard was applicable to the feldspathic porcelain and produced very comparable results with the numeric toughness calculations of the IS procedure. However, fractographic analysis of the surface crack was somewhat difficult for this glassy ceramic compared with polycrystalline ceramics. Knowledge about stable crack extension or slow crack growth and its fractographic appearance is essential when estimating the toughness from examination of flaw dimensions on fractured surfaces since large calculation errors may occur if these effects are not taken into account. (C) 1999 Academy of Dental Materials. Published by Elsevier Science Ltd. All rights reserved. C1 Univ Geneva, Sch Dent, Dept Prosthodont, CH-1205 Geneva, Switzerland. USN, Sch Dent, Naval Dent Res Inst Detachment, Bethesda, MD 20814 USA. Natl Inst Stand & Technol, Dent & Med Mat Grp, Gaithersburg, MD 20899 USA. Natl Inst Stand & Technol, Div Ceram, Gaithersburg, MD 20899 USA. RP Scherrer, SS (reprint author), Univ Geneva, Sch Dent, Dept Prosthodont, CH-1205 Geneva, Switzerland. NR 23 TC 64 Z9 66 U1 0 U2 8 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0109-5641 J9 DENT MATER JI Dent. Mater. PD SEP PY 1999 VL 15 IS 5 BP 342 EP 348 DI 10.1016/S0109-5641(99)00055-X PG 7 WC Dentistry, Oral Surgery & Medicine; Materials Science, Biomaterials SC Dentistry, Oral Surgery & Medicine; Materials Science GA 249JJ UT WOS:000083329600007 PM 10863431 ER PT J AU Gustafson, RG Winans, GA AF Gustafson, RG Winans, GA TI Distribution and population genetic structure of river- and sea-type sockeye salmon in western North America SO ECOLOGY OF FRESHWATER FISH LA English DT Article DE life-history type; genetic variability; sockey salmon; Puget Sound ID GLACIAL TAKU RIVER; ONCORHYNCHUS-NERKA; BRITISH-COLUMBIA; PACIFIC-NORTHWEST; ALASKA; HABITAT; ASIA AB In contrast to the well-known "lake-type" sockeye salmon, two additional anadromous life-history types have been recognized within the species: "river-type" sockeye salmon whose juveniles spend 1 or 2 years in off-channel river habitats prior to migrating to sea, and "sea-type" sockeye salmon that initially rear in similar river habitats yet migrate to sea as underyearlings. Persistent populations of river-/sea-type sockeye salmon occur in small numbers throughout the species' range in North America but are usually associated with glacier-fed rivers. We found published and unpublished records showing that riverine-spawning sockeye salmon occur in 11 rivers in western Washington, USA, that don't have access to juvenile lake-rearing habitat. Evidence of persistent spawning was strongest for the Nooksack and Skagit rivers in northern Puget Sound. We analyzed allozyme frequency differentiation in 26 lake-type and 12 river-/sea-type populations of sockeye salmon in North America, ranging from northern Puget Sound, Washington (including 3 in the Nooksack and Skagit rivers) to northern Southeast Alaska. Across this 2000 km range, river-/sea-type sockeye salmon showed very little genetic differentiation between populations, much less than that displayed by the highly divergent lake-type sockeye salmon. Genetic similarity among river-/sea-type sockeye salmon in this study is likely a result of common ancestry and a high level of historical gene flow among river-/sea-type sockeye salmon populations. C1 NW Fisheries Sci Ctr, Natl Marine Fisheries Serv, Conservat Biol Div, Seattle, WA 98112 USA. RP Gustafson, RG (reprint author), NW Fisheries Sci Ctr, Natl Marine Fisheries Serv, Conservat Biol Div, 2725 Montlake Blvd E, Seattle, WA 98112 USA. NR 62 TC 31 Z9 31 U1 1 U2 6 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0906-6691 J9 ECOL FRESHW FISH JI Ecol. Freshw. Fish PD SEP PY 1999 VL 8 IS 3 BP 181 EP 193 DI 10.1111/j.1600-0633.1999.tb00069.x PG 13 WC Fisheries; Marine & Freshwater Biology SC Fisheries; Marine & Freshwater Biology GA 237RE UT WOS:000082669200009 ER PT J AU Fayer, R Lewis, EJ Trout, JM Graczyk, TK Jenkins, MC Higgins, J Xiao, LH Lal, AA AF Fayer, R Lewis, EJ Trout, JM Graczyk, TK Jenkins, MC Higgins, J Xiao, LH Lal, AA TI Cryptosporidium parvum in oysters from commercial harvesting sites in the Chesapeake Bay SO EMERGING INFECTIOUS DISEASES LA English DT Article ID CRASSOSTREA-VIRGINICA; OOCYSTS; WATER AB Oocysts of Cryptosporidium parvum, a zoonotic waterborne pathogen, can be removed by bivalve molluscs from contaminated water and retained on gills and in hemolymph. We identified oocysts of C. parvum in oysters from seven sites in the Chesapeake Bay area. These findings document the presence of C. parvum infectious for humans in oysters intended for human consumption. C1 ARS, USDA, IDRL, Beltsville, MD 20705 USA. NOAA, Oxford, MD USA. Johns Hopkins Univ, Sch Hyg & Publ Hlth, Baltimore, MD USA. Ctr Dis Control & Prevent, Atlanta, GA USA. RP Fayer, R (reprint author), ARS, USDA, IDRL, 10300 Baltimore Ave,Bldg 1040, Beltsville, MD 20705 USA. RI Xiao, Lihua/B-1704-2013 OI Xiao, Lihua/0000-0001-8532-2727 NR 11 TC 57 Z9 61 U1 1 U2 5 PU CENTER DISEASE CONTROL PI ATLANTA PA ATLANTA, GA 30333 USA SN 1080-6040 J9 EMERG INFECT DIS JI Emerg. Infect. Dis PD SEP-OCT PY 1999 VL 5 IS 5 BP 706 EP 710 PG 5 WC Immunology; Infectious Diseases SC Immunology; Infectious Diseases GA 247GF UT WOS:000083212200013 PM 10511528 ER PT J AU Fairey, ER Edmunds, JSG Deamer-Melia, NJ Glasgow, H Johnson, FM Moeller, PR Burkholder, JM Ramsdell, JS AF Fairey, ER Edmunds, JSG Deamer-Melia, NJ Glasgow, H Johnson, FM Moeller, PR Burkholder, JM Ramsdell, JS TI Reporter gene assay for fish-killing activity produced by Pfiesteria piscicida SO ENVIRONMENTAL HEALTH PERSPECTIVES LA English DT Article DE assay; c-fos; GH(4)C(1); Pfiesteria piscicida; pituitary; toxin ID DOMOIC ACID; DINOFLAGELLATE; BREVETOXINS; CIGUATOXINS; SAXITOXINS; SURVIVAL; EXPOSURE; TOXIN AB Collaborative studies were performed to develop a functional assay for fish-killing activity produced by P. fiesteria piscicida. Eight cell lines were used to screen organic fractions and residual water fraction by using a 3-[4,5-dimethylthiazol-(2-4)]-diphenyltetrazolium bromide cytotoxicity assay. Diethyl ether and a residual water fraction were cytotoxic to several cell lines including rat pituitary (GH(4)C(1)) cells. Residual water as well as preextracted culture water containing P. piscicida cells induced c-fos-luciferase expressed in GH(4)C(1) cells with a rapid time course of induction and sensitive detection. The reporter gene assay detected activity in toxic isolates of P. piscicida from several North Carolina estuaries in 1997 and 1998 and may also be suitable for detecting toxic activity in human and animal serum. C1 Natl Ocean Serv, NOAA, Ctr Coastal Environm Hlth & Biomol Res, Marine Biotoxins Program, Charleston, SC 29412 USA. N Carolina State Univ, Dept Bot, Raleigh, NC 27695 USA. NIEHS, Intramural Res Program, Res Triangle Pk, NC 27709 USA. NIEHS, Environm Toxicol Program, Res Triangle Pk, NC 27709 USA. RP Ramsdell, JS (reprint author), Natl Ocean Serv, NOAA, Ctr Coastal Environm Hlth & Biomol Res, Marine Biotoxins Program, 219 Ft Johnson Rd, Charleston, SC 29412 USA. NR 17 TC 53 Z9 55 U1 0 U2 2 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 SEP PY 1999 VL 107 IS 9 BP 711 EP 714 DI 10.2307/3434655 PG 4 WC Environmental Sciences; Public, Environmental & Occupational Health; Toxicology SC Environmental Sciences & Ecology; Public, Environmental & Occupational Health; Toxicology GA 236BT UT WOS:000082578900021 PM 10464070 ER PT J AU Bamford, HA Poster, DL Baker, JE AF Bamford, HA Poster, DL Baker, JE TI Temperature dependence of Henry's law constants of thirteen polycyclic aromatic hydrocarbons between 4 degrees C and 31 degrees C SO ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY LA English DT Article DE Henry's law constant; polycyclic aromatic hydrocarbons; temperature dependence; enthalpy; phase change ID AIR-WATER-INTERFACE; POLYCHLORINATED-BIPHENYLS; ORGANIC CONTAMINANTS; CHESAPEAKE BAY; LAKE-MICHIGAN; ATMOSPHERIC DEPOSITION; EXCHANGE; FLUXES; PAHS; HEXACHLOROCYCLOHEXANES AB An understanding of the temperature dependence of the Henry's law constant for organic contaminants is critical when modeling the transport and fate of these contaminants in the environment. The Henry's law constants for 13 polycyclic aromatic hydrocarbons (PAHs) were experimentally determined between 4 and 31 degrees C using a gas-stripping apparatus. The Henry's law constants ranged between 0.02 +/- 0.01 Pa m(3)/mol for chrysene at 4 degrees C and 73.3 +/- 20 Pa m(3)/mol for 2-methylnaphthalene at 31 degrees C. The temperature dependence of each PAH was modeled using the van't Hoff equation to calculate the enthalpy and entropy of phase change. For nine of the PAHs, the present study reports the first experimental measured temperature dependence of their Henry's law constant. The enthalpies of phase change ranged between 35.4 +/- 1.9 kJ/mol for 1-methylphenanthrene and 100 +/- 8 kJ/mol for chrysene. These data can be used to extrapolate Henry's law values within the experimental temperature ranges. For all PAHs except benzo[a]fluorene, the temperature dependence can be predicted within a relative standard error <10%. C1 Univ Maryland, Chesapeake Biol Lab, Ctr Environm Sci, Solomons, MD 20688 USA. Natl Inst Stand & Technol, Div Analyt Chem, Chem Sci & Technol Lab, Gaithersburg, MD 20899 USA. RP Baker, JE (reprint author), Univ Maryland, Chesapeake Biol Lab, Ctr Environm Sci, POB 38, Solomons, MD 20688 USA. RI Baker, Joel/A-9685-2011 OI Baker, Joel/0000-0002-9980-7781 NR 47 TC 88 Z9 90 U1 3 U2 27 PU SETAC PRESS PI PENSACOLA PA 1010 NORTH 12TH AVE, PENSACOLA, FL 32501-3370 USA SN 0730-7268 J9 ENVIRON TOXICOL CHEM JI Environ. Toxicol. Chem. PD SEP PY 1999 VL 18 IS 9 BP 1905 EP 1912 DI 10.1897/1551-5028(1999)018<1905:TDOHSL>2.3.CO;2 PG 8 WC Environmental Sciences; Toxicology SC Environmental Sciences & Ecology; Toxicology GA 229NY UT WOS:000082201700006 ER PT J AU Walsh, HJ Peters, DS Cyrus, DP AF Walsh, HJ Peters, DS Cyrus, DP TI Habitat utilization by small flatfishes in a North Carolina estuary SO ESTUARIES LA English DT Article; Proceedings Paper CT 3rd Annual Marine and Estuarine Shallow Water Science and Management Conference CY DEC 01-05, 1996 CL ATLANTIC CITY, NEW JERSEY ID USA; PLEURONECTIFORMES; CYNOGLOSSIDAE; PARALICHTHYS; TONGUEFISHES; SETTLEMENT; TURBIDITY; SYMPHURUS; PATTERN; GEORGIA AB Distribution and abundance of flatfish species (< 150 mm standard length) were related to habitat characteristics in the Newport River and Back Sound estuaries in North Carolina. Salinity, turbidity, depth, distance from marsh edge, benthic composition, and grain size were used to describe the different shallow water habitats from April through October 1994. One Scophthalmidae, seven Paralichthyidae, one Achiridae, and one Cynoglossidae species were collected during the study including juvenile Paralichthys albigutta (gulf flounder), P. dentatus (summer flounder), and P. lethostigma (southern flounder) along with multiple age classes of Citharichthys spilopterus (bay whiff), Eh-opus crossotus (fringed flounder), Symphurus plagiusa (blackcheek tonguefish), and Trinetes maculatus (hogchoker). Incidental catches of Ancylopsetta quadrocellata (ocellated flounder), C. macrops (spotted whiff), and Scopthalmus aquosus (windowpane) were also made. Flatfish distributions among habitats varied by species, size within species, and season. Regardless of season, the highest densities of flatfishes were found in the upper estuary. All habitats were used by one or more species and most species occurred at several habitats. Some species were significantly more abundant at specific habitat types. Ontogenetic shifts in habitat utilization were found for several species. High densities of small P. lethostigma, C. spilopterus, S. plagiusa, and T. maculatus occurred in the upper estuary on muddy substrates. Large P. dentatus, C. spilopterus, S. plagiusa, and T: maculatus utilized sand flats and channels in the lower estuary. C1 NOAA, Natl Ocean Serv, Beaufort Lab, Beaufort, NC 28516 USA. Univ Zululand, Coastal Res Unit Zululand, ZA-3886 Kwa Dlangezwa, South Africa. RP Walsh, HJ (reprint author), NOAA, Natl Ocean Serv, Beaufort Lab, 101 Pivers Isl Rd, Beaufort, NC 28516 USA. NR 35 TC 34 Z9 34 U1 2 U2 11 PU ESTUARINE RES FEDERATION PI LAWRENCE PA PO BOX 368, LAWRENCE, KS 66044 USA SN 0160-8347 J9 ESTUARIES JI Estuaries PD SEP PY 1999 VL 22 IS 3B BP 803 EP 813 DI 10.2307/1353113 PG 11 WC Environmental Sciences; Marine & Freshwater Biology SC Environmental Sciences & Ecology; Marine & Freshwater Biology GA 246BE UT WOS:000083142600009 ER PT J AU Hubertz, ED Cahoon, LB AF Hubertz, ED Cahoon, LB TI Short-term variability of water quality parameters in two shallow estuaries of North Carolina SO ESTUARIES LA English DT Article; Proceedings Paper CT 3rd Annual Marine and Estuarine Shallow Water Science and Management Conference CY DEC 01-05, 1996 CL ATLANTIC CITY, NEW JERSEY ID NEUSE RIVER ESTUARY; TIDAL ESTUARY; ENVIRONMENTAL VARIABILITY; PHYTOPLANKTON PRODUCTION; NUTRIENT LIMITATION; CHLOROPHYLL-A; ENHANCEMENT; ABUNDANCE; PATTERNS; RAINFALL AB We quantified the effects of nutrient loading following precipitation events (greater than or equal to 1.25 cm) in 2 tidal creeks varying in size and anthropogenic input during the winter and summer seasons of 1996. Several water quality parameters were repeatedly measured in the water column every 3 h for several days after each event (4-5 per season). Total nitrogen (TN) and total phosphorus (TP) behaved nonconservatively with salinity and appeared as pulsed additions, occasionally doubling within 1 to 2 tidal cycles following significant rain events. Average values for TN, TP, and chlorophyll a were 10-15 mu M, < 4 mu M, and < 7 mu g l(-1), respectively for winter events and 30-35 mu M, > 4 mu M, and greater than or equal to 7 mu g l(-1), respectively for summer events. However, response times were variable, depending on the magnitude and duration of the event as well as temperature. Chlorophyll a biomass often increased after nutrient additions, especially in the summer when increased nutrient loading took place. Dissolved silica (DSi) behaved conservatively with salinity; low values were observed at high tide and vice versa. Average DSi ranges for winter;Ind summer events were 5-45 mu M and 10-85 mu M, respectively. DSi range values increased proportionally with the amount of freshwater loaded into the system. Recovery times for salinity were usually greater than the recovery times for nutrients. Dissolved oxygen displayed a diel pattern, increasing after daytime productivity and decreasing during nighttime. In conclusion, each rainfall event was unique and responses were variable depending upon rainfall history, seasonality, and the duration and intensify of the rainfall event. Several other variables, such as water viscosity, percolation rates, and evapotranspiration rates which were not quantified in this study, could have also explained parameter responses. C1 NOAA, Estuarine Reserves Div, Off Ocean & Coastal Resource Management, Silver Spring, MD 20910 USA. Univ N Carolina, Dept Biol Sci, Wilmington, NC 28403 USA. RP Hubertz, ED (reprint author), NOAA, Estuarine Reserves Div, Off Ocean & Coastal Resource Management, 1305 East West Highway N-ORM5, Silver Spring, MD 20910 USA. NR 36 TC 34 Z9 34 U1 4 U2 11 PU ESTUARINE RES FEDERATION PI LAWRENCE PA PO BOX 368, LAWRENCE, KS 66044 USA SN 0160-8347 J9 ESTUARIES JI Estuaries PD SEP PY 1999 VL 22 IS 3B BP 814 EP 823 DI 10.2307/1353114 PG 10 WC Environmental Sciences; Marine & Freshwater Biology SC Environmental Sciences & Ecology; Marine & Freshwater Biology GA 246BE UT WOS:000083142600010 ER PT J AU Cognet, L Savalli, V Featonby, PD Helmerson, K Westbrook, N Westbrook, CI Phillips, WD Aspect, A Zabow, G Drndic, M Lee, CS Westervelt, RM Prentiss, M AF Cognet, L Savalli, V Featonby, PD Helmerson, K Westbrook, N Westbrook, CI Phillips, WD Aspect, A Zabow, G Drndic, M Lee, CS Westervelt, RM Prentiss, M TI Smoothing a current-carrying atomic mirror SO EUROPHYSICS LETTERS LA English DT Article ID CESIUM ATOMS; REFLECTION AB We have measured the magnitude and roughness of the reflecting potential produced by a current-carrying magnetic mirror from which cold rubidium atoms have been bounced at normal incidence. By varying the current in the mirror, a study of the potential barrier from which the atoms in different magnetic substates bounce has been made. A combination of time-of-flight and imaging techniques allowed us to study the roughness of the reflecting potential. We have demonstrated that the observed roughness can be reduced by additional wires to compensate for the finite-size effects, and by careful control of the direction of the magnetic bias field. C1 Inst Opt, UM CNRS 8501, Lab Charles Fabry, F-91403 Orsay, France. Harvard Univ, Dept Phys, Cambridge, MA 02138 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Cognet, L (reprint author), Inst Opt, UM CNRS 8501, Lab Charles Fabry, BP 147, F-91403 Orsay, France. RI Westbrook, Christoph/B-6092-2009; Cognet, Laurent/F-4163-2011; Helmerson, Kristian/E-3683-2013 OI Westbrook, Christoph/0000-0002-6490-0468; Cognet, Laurent/0000-0002-3573-5387; NR 13 TC 16 Z9 17 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 0295-5075 J9 EUROPHYS LETT JI Europhys. Lett. PD SEP 1 PY 1999 VL 47 IS 5 BP 538 EP 544 DI 10.1209/epl/i1999-00421-1 PG 7 WC Physics, Multidisciplinary SC Physics GA 232MF UT WOS:000082374000002 ER PT J AU Cooper, LY Franssen, JM AF Cooper, LY Franssen, JM TI A basis for using fire modeling with 1-D thermal analyses of partitions to simulate 2-D and 3-D structural performance in real fires SO FIRE SAFETY JOURNAL LA English DT Article AB Computer fire models for simulating compartment fire environments typically require a mathematical formulation that couples the thermal response of the gases that fill the compartment and the thermal response of compartment partitions. The fire environment characteristics calculated by such models can be used to provide input, via thermal boundary conditions, to an uncoupled thermal-structural computer model for simulating and evaluating the combined thermal/structural performance of the partitions. The objective of such a combined analysis would be to determine, through analysis, the structural fire resistance of a partition design. Depending on the particular partition design of interest, the latter thermal/structural part of the problem would generally require a two- and possibly three-dimensional analysis. As it turns out, there are several quality tools of analysis (e.g., some of those reviewed in Ref. [1]), mainly for non-combustible construction, that are available for use in solving the latter problem. However, because of intense computational requirements, the general use of a multi-dimensional (vs. a one-dimensional) partition thermal analysis in the fire modeling part of the problem is not now practical. A basis is presented for identifying partition designs for which: (1) the use of one-dimensional thermal analysis in the fire modeling part of the problem would lead to reliable simulations of the fire environment, and (2) the resulting simulations can be used to provide the necessary boundary conditions input to solve the thermal/structural part of the problem, using two- or three-dimensional analyses, as required. Published by Elsevier Science Ltd. C1 Natl Inst Stand & Technol, Bldg & Fire Res Lab, Gaithersburg, MD 20899 USA. Univ Liege, Inst Civil Engn, Liege, Belgium. RP Cooper, LY (reprint author), Hughes Associates Inc, Fire Sci & Engn, Baltimore, MD 21227 USA. NR 15 TC 2 Z9 2 U1 0 U2 1 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0379-7112 J9 FIRE SAFETY J JI Fire Saf. J. PD SEP PY 1999 VL 33 IS 2 BP 115 EP 128 DI 10.1016/S0379-7112(99)00018-1 PG 14 WC Engineering, Civil; Materials Science, Multidisciplinary SC Engineering; Materials Science GA 245KZ UT WOS:000083108600003 ER PT J AU Braun, E Womeldorf, CA Grosshandler, WL AF Braun, E Womeldorf, CA Grosshandler, WL TI Suppression concentration of clean agents exposed to a continuously energized heated metal surface SO FIRE SAFETY JOURNAL LA English DT Article ID IGNITION AB An apparatus for the determination of autoignition temperature of hydrocarbon fuels has been used to measure the change in ignition temperature of a stoichiometric mixture of ethene/air with and without the addition of a suppressant: N-2, IG-542, HFC-23, KFC-227ea, FC-218 or FC-3-1-10. When exposed to a heated metal surface of nickel, a fuel/air stream with clean agent added generally required higher temperatures to ignite than when no agent was present. For some agents at low concentrations, it was found that ignition occurred at temperatures lower than when no agent was present. As agent concentration was increased, ignition became harder, i.e., the temperature required for ignition was higher. For each of these suppressants, with foil temperatures approaching 1000 degrees C, the agent concentration necessary to prevent ignition of the ethene/air mixture exceeded the total flooding and met or exceeded the inerting design concentrations recommended in NFPA 2001, the Standard on Clean Agent Fire Extinguishing Systems. Published by Elsevier Science Ltd. C1 Natl Inst Stand & Technol, Bldg & Fire Res Lab, Gaithersburg, MD 20899 USA. RP Womeldorf, CA (reprint author), Natl Inst Stand & Technol, Bldg & Fire Res Lab, Room B356,Bldg 224, Gaithersburg, MD 20899 USA. NR 12 TC 1 Z9 3 U1 1 U2 3 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0379-7112 J9 FIRE SAFETY J JI Fire Saf. J. PD SEP PY 1999 VL 33 IS 2 BP 141 EP 152 DI 10.1016/S0379-7112(99)00011-9 PG 12 WC Engineering, Civil; Materials Science, Multidisciplinary SC Engineering; Materials Science GA 245KZ UT WOS:000083108600005 ER PT J AU Payne, SA Johnson, BA Otto, RS AF Payne, SA Johnson, BA Otto, RS TI Proximate composition of some north-eastern Pacific forage fish species SO FISHERIES OCEANOGRAPHY LA English DT Article DE boxplot; caloric content; forage fish species; graphical analysis; iterative reweighted least squares; proximate analysis ID STELLER SEA LIONS; CALLORHINUS-URSINUS; EUMETOPIAS-JUBATUS; ALASKA; GULF; DECLINE; ISLAND; NUMBER AB To understand the relative dietary value of forage fish as prey in the Bering Sea and Gulf of Alaska, whole organisms of 13 species were analysed for proximate composition (protein, oil, ash and moisture content). Eulachon (Thaleichthys pacificus) were high in oil (total lipid) (16.8% to 21.4%) and low in moisture (64.6% to 70.8%). Oil in capelin (Mallotus villosus) ranged from 2.1% to 14.0%. Juveniles of walleye pollock (Theragra chalcogramma), Atka mackerel (Pleurogrammus monopterygius), Pacific herring (Clupea pallasii), and prowfish (Zaprora silenus) had low oil contents (< 1.8%) and high moisture contents (> 80.3%). Rankings of median proximate values illustrate the similarities. Surf smelt (Hypomesus pretiosus), rainbow smelt (Osmerus mordax), pricklebacks (Lumpenus spp.), Atka mackerel, Pacific sand lance (Ammodytes hexapterus) and Pacific sandfish (Trichodon trichodon) ranked high in median protein content (> 15.4%). Median ash content for all species ranged from 0.6% to 3.3%. Total wet mass caloric content (kcal g(-1)) was calculated for the four main species and a linear model was developed for caloric content as a function of moisture. The linear models (caloric content = b(0) + b(1) x moisture) were Pacific sand lance and Pacific sandfish (b(0) = 7.82, b(1) = - 0.09); eulachon (b(0) = 7.97, b(1) = - 0.08); and capelin (b(0) = 9.70, b(1) = - 0.11). C1 Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr, Kodiak, AK 99615 USA. RP Payne, SA (reprint author), Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr, POB 1638, Kodiak, AK 99615 USA. NR 45 TC 52 Z9 56 U1 2 U2 21 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD OX2 0NE, OXON, ENGLAND SN 1054-6006 J9 FISH OCEANOGR JI Fish Oceanogr. PD SEP PY 1999 VL 8 IS 3 BP 159 EP 177 DI 10.1046/j.1365-2419.1999.00097.x PG 19 WC Fisheries; Oceanography SC Fisheries; Oceanography GA 262UH UT WOS:000084084500001 ER PT J AU Bigelow, KA Boggs, CH He, X AF Bigelow, KA Boggs, CH He, X TI Environmental effects on swordfish and blue shark catch rates in the US North Pacific longline fishery SO FISHERIES OCEANOGRAPHY LA English DT Article DE blue shark; fishery oceanography; generalized additive models; longline fishery; North Pacific; remote sensing; swordfish ID SUB-TROPICAL FRONT; TUNA CATCH; SOUND-VELOCITY; BERING SEA; GULF; MEXICO; ASSOCIATION; TEMPERATURE; MOVEMENTS; YELLOWFIN AB Generalized additive models (GAMs) were applied to examine the relative influence of various factors on fishery performance, defined as nominal catch- per-unit-effort (CPUE) of swordfish (Xiphias gladius) and blue shark (Prionace glauca) in the Hawaii-based swordfish fishery. Commercial fisheries data for the analysis consisted of a 5 year (1991-1995) time series of 27 901 longline sets. Mesoscale relationships were analysed for seven physical variables (latitude, longitude, SST, SST frontal energy, temporal changes in SST (Delta SST), SST frontal energy (Delta SST frontal energy) and bathymetry), all of which may affect the availability of swordfish and blue shark to the fishery, and three variables (number of lightsticks per hook, lunar index, and wind velocity) which may relate to the effectiveness of the fishing gear. Longline CPUE data were analysed in relation to SST data on three spatiotemporal scales (18 km weekly, 1 degrees-weekly, 1 degrees-monthly). Depending on the scale of SST data, GAM analysis accounted for 39-42% and 44-45% of the variance in nominal CPUE for swordfish and blue shark, respectively. Stepwise GAM building revealed the relative importance of the variables in explaining the variance in CPUE. For swordfish, by decreasing importance, the variables ranked: (1) latitude, (2) time, (3) longitude, (4) lunar index, (5) lightsticks per hook, (6) SST, (7) Delta SST frontal energy, (8) wind velocity, (9) SST frontal energy, (10) bathymetry, and (11) Delta SST. For blue shark, the variables ranked: (1) latitude, (2) longitude, (3) time, (4) SST, (5) lightsticks per hook, (6) Delta SST, (7) Delta SST frontal energy, (8) SST frontal energy, (9) wind velocity, (10) lunar index, and (11) bathymetry. Swordfish CPUE increased with latitude to peak at 35-40 degrees N and increased in the vicinity of temperature fronts and during the full moon. Shark CPUE also increased with latitude up to 40 degrees N, and increased westward, but declined abruptly at SSTs colder than 16 degrees C. As a comparison with modelling fishery performance in relation to specific environmental and fishery operational effects, fishery performance was also modelled as a function of categorical time (month) and area (2 degrees squares) variables using a generalized linear model (GLM) approach. The variance accounted for by the GLMs was approximate to 1-3% lower than the variance explained by the GAMs. Time series of swordfish and blue shark CPUE standardized for the environmental and operational variables quantified in the GAM and for the time-area effects in the GLM are presented. For swordfish, both nominal and standardized time series indicate a decline in CPUE, whereas the opposite trend was seen for blue shark. C1 Univ Hawaii, Joint Inst Marine & Atmospher Res, Pelag Fisheries Res Program, Honolulu, HI 96822 USA. NOAA, Natl Marine Fisheries Serv, SW Fisheries Sci Ctr, Honolulu Lab, Honolulu, HI 96822 USA. RP Bigelow, KA (reprint author), Ocean Fisheries Programme, SPC, BP D5, Noumea 98848, New Caledonia. NR 64 TC 142 Z9 167 U1 4 U2 28 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD OX2 0NE, OXON, ENGLAND SN 1054-6006 J9 FISH OCEANOGR JI Fish Oceanogr. PD SEP PY 1999 VL 8 IS 3 BP 178 EP 198 DI 10.1046/j.1365-2419.1999.00105.x PG 21 WC Fisheries; Oceanography SC Fisheries; Oceanography GA 262UH UT WOS:000084084500002 ER PT J AU Page, FH Sinclair, M Naimie, CE Loder, JW Losier, RJ Berrien, PL Lough, RG AF Page, FH Sinclair, M Naimie, CE Loder, JW Losier, RJ Berrien, PL Lough, RG TI Cod and haddock spawning on Georges Bank in relation to water residence times SO FISHERIES OCEANOGRAPHY LA English DT Article DE circulation model; cod; eggs; Georges Bank; haddock; residence time; spawning ID GULF-OF-MAINE; MELANOGRAMMUS-AEGLEFINUS; CIRCULATION; MODEL; EGG AB The seasonal and geographical patterns of spawning for Georges Bank cod (Gadus morhua) and haddock (Melanogrammus aeglefinus) are estimated using composite distributions of stage I eggs derived from the Marine Resources Monitoring, Assessment and Prediction (MARMAP) data set (1977-1987). The inferred mean spawning locations are compared with patterns in particle residence times derived from a three-dimensional prognostic circulation model that estimates the tidal and seasonal mean circulation. The comparisons indicate that cod and haddock spawning occurs at times and locations characterized by model residence times in excess of 35 d. The results are discussed in the context of fish population regulation theory, particularly the member/vagrant hypothesis and the concept of abundance-dependent vagrancy. C1 Fisheries & Oceans Canada, Biol Stn, St Andrews, NB E0G 2X0, Canada. Fisheries & Oceans Canada, Bedford Inst Oceanog, Dartmouth, NS B2Y 4A2, Canada. Dartmouth Coll, Hanover, NH 03755 USA. Natl Marine Fisheries Serv, Sandy Hook, NJ USA. NOAA, Natl Marine Fisheries Serv, NE Fisheries Sci Ctr, Woods Hole, MA 02543 USA. RP Page, FH (reprint author), Fisheries & Oceans Canada, Biol Stn, St Andrews, NB E0G 2X0, Canada. EM pagef@mar.dfo-mpo.gc.ca NR 38 TC 27 Z9 30 U1 0 U2 5 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 1054-6006 J9 FISH OCEANOGR JI Fish Oceanogr. PD SEP PY 1999 VL 8 IS 3 BP 212 EP 226 DI 10.1046/j.1365-2419.1999.00108.x PG 15 WC Fisheries; Oceanography SC Fisheries; Oceanography GA 262UH UT WOS:000084084500004 ER PT J AU Shimizu, M Swanson, P Dickhoff, WW AF Shimizu, M Swanson, P Dickhoff, WW TI Free and protein-bound insulin-like growth factor-I (IGF-I) and IGF-binding proteins in plasma of coho salmon, Oncorhynchus kisutch SO GENERAL AND COMPARATIVE ENDOCRINOLOGY LA English DT Article DE insulin-like growth factor-I (IGF-I); free IGF-I; IGF-binding protein; salmon; growth hormone; fasting ID MORONE-SAXATILIS; STRIPED BASS; BIOLOGICAL ACTIONS; RAINBOW-TROUT; SERUM; FISH; HORMONE; RADIOIMMUNOASSAY; CIRCULATION; SOMATOMEDIN AB Total and free insulin-like growth factor-I (IGF-I) levels were quantified in plasma from growth hormone (GH)-treated and fasted coho salmon. Total IGF-I was measured by radioimmunoassay after acid-ethanol extraction and free IGF-I was separated from protein-bound IGF-I using ultrafiltration by centrifugation. Total and free TGF-I increased in plasma after GH treatment and decreased after fasting. The level of free IGF-I, however, was maintained at approximately 0.3% in both experiments. Unsaturated binding activity in plasma for IGF-I was assessed by incubation with I-125-recombinant salmon IGF-I (I-125-sIGF-I). Although there was no difference in binding activity between GH-treated and control fish, fasted fish showed higher binding activity than did fed fish, suggesting induction of unsaturated binding protein by fasting. IGF-binding protein (IGFBP) bands were observed in plasma of coho salmon by Western ligand blotting using I-125-sIGF-I. A low-molecular-weight (22 kDa) band was clear in fasted fish but not detectable in fed fish. The IGFBP band, which has molecular weight similar to that of human IGFBP-3 (41 kDa), was more intense in GH-treated fish than in controls. The molecular distribution of IGF-1 in plasma was examined by gel filtration under neutral conditions. Most IGF-I was eluted around 40 kDa. This result suggests that the major form of bound IGF-I in the circulation of coho salmon may be in a 40-kDa binary complex rather than in a 150-kDa ternary complex, as in mammals. C1 Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, Seattle, WA 98112 USA. Univ Washington, Sch Fisheries, Seattle, WA 98195 USA. RP Shimizu, M (reprint author), Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, 2725 Montlake Blvd E, Seattle, WA 98112 USA. NR 43 TC 94 Z9 96 U1 0 U2 5 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0016-6480 J9 GEN COMP ENDOCR JI Gen. Comp. Endocrinol. PD SEP PY 1999 VL 115 IS 3 BP 398 EP 405 DI 10.1006/gcen.1999.7328 PG 8 WC Endocrinology & Metabolism SC Endocrinology & Metabolism GA 236KY UT WOS:000082599800010 PM 10480991 ER PT J AU Vomel, H Oltmans, SJ AF Vomel, H Oltmans, SJ TI Comment on "A reexamination of the 'stratospheric fountain' hypothesis" by A. E. Dessler SO GEOPHYSICAL RESEARCH LETTERS LA English DT Editorial Material AB Dessler (1998) analyzed 60,000 radiosonde profiles to re-examine an analysis done nearly 20 years earlier by Newell and Gould-Stewart (1981) (hereafter: NGS). Contrary to NGS, Dessler finds that the mean tropical tropopause saturation mixing ratio (SMR) is sufficient to explain stratospheric dryness and that there is no need to assume a seasonal or regional preference for water vapor entering the stratosphere. However, in using the SMR to compute the water vapor amount, he implicitly assumes that the air is saturated, since only under this condition are temperature and water vapor physically connected. If the air is not saturated, the average computed by Dessler will overestimate the amount of water crossing the tropical tropopause ([H2O],), while supersaturation and the presence of ice particles will underestimate [H2O],. These processes, which are likely to have different regional and temporal distributions, may have fortuitously canceled each other in Dessler's analysis. NGS studied the distribution of tropopause temperatures and focused on the regions and seasons, in which dehydration is more likely to take place. Recent studies indicate that the tropical tropopause has been cooling over the last 25 years and show that the years used by Dessler have the coldest tropical tropopause temperatures. Thus his conclusion may have been different if other years had been studied. These differing viewpoints emphasize the need for a detailed understanding of the stratospheric dehydration mechanism. C1 NOAA, Climate Monitoring & Diagnost Lab, Boulder, CO 80303 USA. Univ Colorado, Program Ocean & Atmospher Sci, Boulder, CO 80309 USA. RP Vomel, H (reprint author), NOAA, Climate Monitoring & Diagnost Lab, 325 Broadway, Boulder, CO 80303 USA. RI Dessler, Andrew/G-8852-2012 OI Dessler, Andrew/0000-0003-3939-4820 NR 6 TC 15 Z9 15 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 SEP 1 PY 1999 VL 26 IS 17 BP 2737 EP 2738 DI 10.1029/1999GL900593 PG 2 WC Geosciences, Multidisciplinary SC Geology GA 232VR UT WOS:000082391100025 ER PT J AU Dixon, KW Delworth, TL Spelman, MJ Stouffer, RJ AF Dixon, KW Delworth, TL Spelman, MJ Stouffer, RJ TI The influence of transient surface fluxes on North Atlantic overturning in a coupled GCM climate change experiment SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID OCEAN-ATMOSPHERE MODEL; INCREASE; CO2 AB The mechanism by which the model-simulated North Atlantic thermohaline circulation (THC) weakens in response to increasing greenhouse gas (GHG) forcing is investigated through the use of a set of five multi-century experiments. Using a coarse resolution version of the GFDL coupled climate model, the role of various surface fluxes in weakening the THC is assessed. Changes in net surface freshwater fluxes (precipitation, evaporation, and runoff from land) are found to be the dominant cause for the model's THC weakening. Surface heat flux changes brought about by rising GHG levels also contribute to THC weakening, but are of secondary importance. Wind stress variations have negligible impact on the THC's strength in the transient GHG experiment. C1 NOAA, GFDL, Princeton, NJ 08542 USA. RP Dixon, KW (reprint author), NOAA, GFDL, POB 308, Princeton, NJ 08542 USA. RI Delworth, Thomas/C-5191-2014; Dixon, Keith/L-7120-2015 OI Dixon, Keith/0000-0003-3044-326X NR 13 TC 71 Z9 71 U1 1 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 SEP 1 PY 1999 VL 26 IS 17 BP 2749 EP 2752 DI 10.1029/1999GL900571 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 232VR UT WOS:000082391100029 ER PT J AU Angell, JK AF Angell, JK TI Comparison of surface and tropospheric temperature trends estimated from a 63-station radiosonde network, 1958-1998 SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID AIR-TEMPERATURE; SATELLITE; RECORDS; LAYER AB Comparisons of surface and tropospheric (850-300 mb) temperature trends for climate zones, hemispheres and globe are presented for the period 1958-1998, based on seasonal and annual-mean temperatures from a 63-station radiosonde network. Globally, the surface warmed by 0.14+/- 0.13K/decade during the 41-year period, the 850-300 mb layer by 0.10+/-0.09K/decade. This small difference in global trend results from the surface warming by 0.12K/decade relative to the 850-300 mb layer in the northern hemisphere, but the 850-300 mb layer warming by 0.04K/decade relative to the surface in the southern hemisphere. In north polar and temperate zones the warming of the surface relative to the 850-300 mb layer is greatest in winter-spring and there is little difference in trend in summer. There is a tendency for a similar seasonal variation in trend difference in south extratropics, warming of the surface relative to the 850-300 mb layer occurring only in winter in the south polar zone, and cooling of the surface relative to the 850-300 mb layer greatest in summer in the south temperate zone. Globally, the warming of the surface relative to the 850-300 mb layer is 0.11K/decade during 1979-1998, compared to 0.04K/decade during 1958-1998, but with the 95% confidence intervals approximately twice as great for the 20-year period as for the 41-year period. C1 NOAA, Air Resources Lab, Silver Spring, MD 20910 USA. RP Angell, JK (reprint author), NOAA, Air Resources Lab, 1315 East West Highway, Silver Spring, MD 20910 USA. NR 22 TC 27 Z9 33 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 SEP 1 PY 1999 VL 26 IS 17 BP 2761 EP 2764 DI 10.1029/1999GL900375 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 232VR UT WOS:000082391100032 ER PT J AU Randerson, JT Field, CB Fung, IY Tans, PP AF Randerson, JT Field, CB Fung, IY Tans, PP TI Increases in early season ecosystem uptake explain recent changes in the seasonal cycle of atmospheric CO2 at high northern latitudes SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID CARBON-DIOXIDE; TERRESTRIAL SOURCES; PLANT-GROWTH; MODEL; FOREST; SINKS AB We report changes in the seasonal cycle of atmospheric CO2 at high northern latitudes from 1980 to 1997 based on NOAA/CMDL observation stations. Using a combination of biogeochemical and atmospheric modeling approaches, we show that increases in early season net ecosystem uptake explain the recent trends in the seasonal cycle. A strong year-to-year correlation between spring temperatures and early season uptake further suggests that increased photosynthetic activity is the primary mechanism. At the end of the growing season, a strong correlation between fall temperatures and late season releases provides evidence for a large active pool of decomposing soil carbon. Taken together, our results suggest that the seasonal timing of temperature anomalies may have important consequences for the interannual carbon balance of northern ecosystems. C1 Carnegie Inst Washington, Dept Plant Biol, Stanford, CA 94305 USA. NOAA, Climate Monitoring & Diagnost Lab, Boulder, CO 80303 USA. Stanford Univ, Dept Biol Sci, Stanford, CA 94305 USA. Univ Calif Berkeley, Ctr Atmospher Sci, Berkeley, CA 94720 USA. RP Randerson, JT (reprint author), Univ Calif Berkeley, Ctr Atmospher Sci, McCone Hall, Berkeley, CA 94720 USA. NR 20 TC 150 Z9 156 U1 2 U2 35 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 SEP 1 PY 1999 VL 26 IS 17 BP 2765 EP 2768 DI 10.1029/1999GL900500 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 232VR UT WOS:000082391100033 ER PT J AU Nevison, CD Keim, ER Solomon, S Fahey, DW Elkins, JW Loewenstein, M Podolske, JR AF Nevison, CD Keim, ER Solomon, S Fahey, DW Elkins, JW Loewenstein, M Podolske, JR TI Constraints on N2O sinks inferred from observed tracer correlations in the lower stratosphere SO GLOBAL BIOGEOCHEMICAL CYCLES LA English DT Article ID WINTER POLAR STRATOSPHERES; NITROUS-OXIDE; 3-DIMENSIONAL MODEL; ATMOSPHERIC N2O; DENITRIFICATION; RATIOS; TRANSPORT; EMISSIONS; AIRCRAFT; ABOARD AB Recent isotopic studies have suggested that the trace gas N2O has a missing stratospheric sink of potentially major significance. While these studies have raised interesting questions, the constraints on N2O photochemistry imposed by correlations between N2O, total reactive nitrogen, and other tracers measured in situ in the lower stratosphere also should be considered. Measured tracer correlations, when compared to the results of models using standard photochemistry, provide evidence in support of conventional N2O sinks. Stratospheric tracer correlations, however, cannot be used to preclude a new atmospheric source of N2O in the troposphere or to argue against an undiscovered stratospheric sink that contributes less than similar to 20% of the total sink. C1 NOAA, Aeron Lab, Boulder, CO 80303 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NOAA, Environm Res Lab, Boulder, CO 80303 USA. Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. RP Nevison, CD (reprint author), Natl Ctr Atmospher Res, POB 3000, Boulder, CO 80307 USA. RI Fahey, David/G-4499-2013 OI Fahey, David/0000-0003-1720-0634 NR 42 TC 6 Z9 6 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0886-6236 J9 GLOBAL BIOGEOCHEM CY JI Glob. Biogeochem. Cycle PD SEP PY 1999 VL 13 IS 3 BP 737 EP 742 DI 10.1029/1999GB900018 PG 6 WC Environmental Sciences; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Geology; Meteorology & Atmospheric Sciences GA 232HK UT WOS:000082365000004 ER PT J AU Miller, JB Yakir, D White, JWC Tans, PP AF Miller, JB Yakir, D White, JWC Tans, PP TI Measurement of O-18/O-16 in the soil-atmosphere CO2 flux SO GLOBAL BIOGEOCHEMICAL CYCLES LA English DT Article ID ISOTOPIC COMPOSITION; CARBON-DIOXIDE; DIRECT EQUILIBRATION; LEAF WATER; OXYGEN; VEGETATION; O-18; DELTA-O-18; EXCHANGE; SURFACE AB Measurements of O-18 in atmospheric CO2 can be used to trace gross photosynthetic and respiratory CO2 fluxes between the atmosphere and the terrestrial biosphere. However, this requires knowledge of the O-18 signatures attributable to the fluxes from soil and leaves. Newly developed methods were employed to measure the O-18 of soil-respired CO2 and depth profiles of near-surface soil CO2 in order to evaluate the factors influencing isotopic soil-atmosphere CO2 exchange. The O-18 soil-respired CO2 varied predominantly as a function of the O-18 of soil water which, in turn, changed with soil drying and with seasonal variations in source water. The O-18 of soil-respired CO2 corresponds to full isotopic equilibrium with soil water at a depth ranging between 5 and 15 cm. The O-18 of respired CO2, in reality, results from a weighted average of partial equilibria over a range of depths. Soil water isotopic enrichment of up to 10 parts per thousand in the top 5 cm did not appear to strongly influence the isotopic composition of the respired CO2. We demonstrate that during measurements "invasion" of atmospheric CO2 (the diffusion of ambient CO2 into the soil, followed by partial equilibration and retrodiffusion) must be considered to accurately calculate the O-18 of the soil-respired CO2. The impact of invasion in natural settings is also considered. We also have determined the effective kinetic fractionation of CO2 diffusion out of the soil to be 7.2 +/- 0.3 parts per thousand. High-resolution (1 cm) depth profiles of O-18 of near-surface (top 10 cm) soil CO2 were carried out by gas chromatography-isotope ratio mass spectrometry (IRMS). This novel technique allowed us to observe the competitive diffusion-equilibration process near the soil surface and to test simulations by a diffusion and equilibration model of the soil CO2 O-18 content. C1 Univ Colorado, Inst Arctic & Alpine Res, Boulder, CO 80309 USA. Weizmann Inst Sci, Dept Environm Sci & Energy Res, IL-76100 Rehovot, Israel. NOAA, Climate Monitoring & Diagnost Lab, Boulder, CO 80303 USA. Univ Colorado, Dept Chem & Biochem, Boulder, CO 80309 USA. Univ Colorado, Dept Geol Sci, Boulder, CO 80309 USA. RP Miller, JB (reprint author), Univ Colorado, Inst Arctic & Alpine Res, Campus Box 450, Boulder, CO 80309 USA. RI White, James/A-7845-2009; Yakir, Dan/K-1500-2012 OI White, James/0000-0001-6041-4684; NR 40 TC 74 Z9 74 U1 0 U2 18 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0886-6236 J9 GLOBAL BIOGEOCHEM CY JI Glob. Biogeochem. Cycle PD SEP PY 1999 VL 13 IS 3 BP 761 EP 774 DI 10.1029/1999GB900028 PG 14 WC Environmental Sciences; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Geology; Meteorology & Atmospheric Sciences GA 232HK UT WOS:000082365000007 ER PT J AU Rose, AH AF Rose, AH TI Playing with fire and fibers SO IEEE CIRCUITS & DEVICES LA English DT Article ID ANNEALED OPTICAL-FIBER; CURRENT SENSORS C1 NIST, Div Optoelect, Boulder, CO USA. RP Rose, AH (reprint author), NIST, Div Optoelect, Boulder, CO USA. NR 7 TC 0 Z9 0 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 8755-3996 J9 IEEE CIRCUITS DEVICE JI IEEE Circuits Devices PD SEP PY 1999 VL 15 IS 5 BP 41 EP 46 DI 10.1109/101.795091 PG 6 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA 241ML UT WOS:000082887000006 ER PT J AU Wakid, S Barkley, J Skall, M AF Wakid, S Barkley, J Skall, M TI Object retrieval and access management in electronic commerce SO IEEE COMMUNICATIONS MAGAZINE LA English DT Article AB Electronic commerce over the Internet is now tens of billions of dollars per year and growing. This article describes how objects used in EC can be located and protected from unauthorized access. It discusses the three kinds of EC: customer interactions with a business, business interactions with other businesses, and interactions within a business. It characterizes the object retrieval and access management required to support the types of EC. It describes how metadata expressed in XML can be used to locate objects for retrieval and how a public key infrastructure along with role-based access control can be used to implement the distributed authentication and access control necessary to support complex access policies. In addition, the article describes activities within the Information Technology Laboratory at the National Institute of Standards and Technology which contribute to the development of related standards and tests. C1 NIST, Informat Technol Lab, Software Diagnost & Conformance Testing Div, Gaithersburg, MD USA. Univ Maryland, Dept Comp Sci, College Pk, MD 20742 USA. RP Wakid, S (reprint author), NIST, Informat Technol Lab, Software Diagnost & Conformance Testing Div, Gaithersburg, MD USA. NR 9 TC 1 Z9 1 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0163-6804 J9 IEEE COMMUN MAG JI IEEE Commun. Mag. PD SEP PY 1999 VL 37 IS 9 BP 74 EP 77 DI 10.1109/35.790905 PG 4 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA 234VA UT WOS:000082504000010 ER PT J AU Maxwell, E Wakid, S Moline, J AF Maxwell, E Wakid, S Moline, J TI A policy perspective on electronic commerce SO IEEE COMMUNICATIONS MAGAZINE LA English DT Article AB The implementation of global electronic commerce is proceeding much more rapidly than initially anticipated. By 2003-2005, electronic commerce revenue is projected to total more than $1 trillion. The U. S. Department of Commerce's "The Emerging Digital Economy II" [1] provides a snapshot of how electronic commerce and information technologies are being used by businesses of all sizes and from all sectors to create new goods and services. Electronic commerce is changing the fundamental relationship between buyers and sellers, producers and consumers. The role of government in providing a policy framework deserves careful examination. C1 US Dept Commerce, Washington, DC 20230 USA. Natl Inst Stand & Technol, Informat Technol Lab, Gaithersburg, MD 20899 USA. RP Maxwell, E (reprint author), US Dept Commerce, Washington, DC 20230 USA. NR 4 TC 1 Z9 1 U1 1 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0163-6804 J9 IEEE COMMUN MAG JI IEEE Commun. Mag. PD SEP PY 1999 VL 37 IS 9 BP 87 EP 91 DI 10.1109/35.790959 PG 5 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA 234VA UT WOS:000082504000013 ER PT J AU Ivezic, N Potok, TE Pouchard, L AF Ivezic, N Potok, TE Pouchard, L TI Multiagent framework for lean manufacturing SO IEEE INTERNET COMPUTING LA English DT Article C1 Oak Ridge Natl Lab, Collaborat Technol Res Ctr, Oak Ridge, TN USA. RP Ivezic, N (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. OI Potok, Thomas/0000-0001-6687-3435 NR 0 TC 9 Z9 10 U1 1 U2 2 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1314 USA SN 1089-7801 J9 IEEE INTERNET COMPUT JI IEEE Internet Comput. PD SEP-OCT PY 1999 VL 3 IS 5 BP 58 EP 59 DI 10.1109/4236.793459 PG 2 WC Computer Science, Software Engineering SC Computer Science GA 239FM UT WOS:000082758200013 ER PT J AU Clemente-Colon, P Yan, XH AF Clemente-Colon, P Yan, XH TI Observations of East Coast upwelling conditions in Synthetic Aperture Radar imagery SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article; Proceedings Paper CT International Geoscience and Remote Sensing Symposium (IGARSS 98) CY 1998 CL SEATTLE, WASHINGTON SP Int Geosci & Remote Sensing Soc DE coastal upwelling; ERS-2 SAR; ocean features; natural slicks; air-sea stability; sea surface backscatter ID SURFACE-FILMS; SEA; WAVES AB Seasonal coastal upwelling in the U.S. Mid-Atlantic coastal ocean normally occurs during the summer months because of generally alongshore southerly wind episodes. Southerly winds force an offshore surface Ekman flow over the inner continental shelf. Colder and nutrient-rich waters from below upwell toward the surface replacing offshore-homing surface waters. Synthetic Aperture Radar (SAR) observations from the European Remote Sensing (ERS) satellite ERS-2 before and after upwelling-favorable mind episodes in early summer 1996 along the New Jersey coast are presented here. Lower backscatter conditions appearing in the SAR imagery after the onset of upwelling demonstrate the influence of the upwelling regime on the sea surface roughness. Satellite sea surface temperature (SST) observations and in-situ sea temperature vertical profiles confirm upwelling conditions, Three key mechanisms are suggested to explain the lower radar returns observed under upwelling conditions, an increase in the atmospheric marine boundary layer stability, an increase in the viscosity of surface waters, and the presence of biogenic surfactants in the upwelling region. C1 NOAA, NESDIS, ORA, Ctr Sci, Camp Springs, MD 20746 USA. Univ Delaware, Ctr Remote Sensing, Newark, DE 19716 USA. RP Clemente-Colon, P (reprint author), NOAA, NESDIS, ORA, Ctr Sci, E-RA3, Camp Springs, MD 20746 USA. RI Clemente-Colon, Pablo/F-5581-2010 NR 24 TC 27 Z9 28 U1 2 U2 4 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD SEP PY 1999 VL 37 IS 5 BP 2239 EP 2248 DI 10.1109/36.789620 PN 1 PG 10 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 236YT UT WOS:000082627400012 ER PT J AU Vivekanandan, J Martner, BE Politovich, MK Zhang, GF AF Vivekanandan, J Martner, BE Politovich, MK Zhang, GF TI Retrieval of atmospheric liquid and ice characteristics using dual-wavelength radar observations SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article; Proceedings Paper CT International Geoscience and Remote Sensing Symposium (IGARSS 98) CY 1998 CL SEATTLE, WASHINGTON SP Int Geosci & Remote Sensing Soc DE absorption; attenuation; dual-wavelength; ice; liquid water content; median volume diameter; microwave radiometer; Mie scattering; radar; Rayleigh; snow ID WATER; RADIOMETER; PARTICLES; CLOUDS; RAIN AB Dual-wavelength (K-a- and X-band) radar measurements have shown promise in estimating the amount of liquid water in a cloud. By taking advantage of the attenuation by liquid water of the K-a-band signal as compared to X-band, the range-differentiated difference in reflectivity can be used to estimate the spatial distribution of cloud liquid water. One limitation is that the method is based on the assumption that all particles in the radar beams act as Rayleigh scatterers, that is, their diameters are small compared to the radar wavelengths. In natural clouds in wintertime conditions, this often may not be the case. This paper presents simulations of the response of these two wavelengths to conditions measured in several geographic locations. The simulations are used to build simplified relations between radar reflectivity and total mass and size distribution functions of liquid droplets and ice particles. Using these relations, it may be possible to estimate the sizes of the droplets, as well as total mass contents and size distributions of ice particles that may also be present in the sampled volume. Results of radar-based retrieval methods applied to measurements in a winter stratiform cloud are discussed, and compared with a previous result. A technique is described for detecting regions of non-Rayleigh scattering and for subsequently estimating liquid water content (LWC). Additional examples of dual-wavelength measurements in regions containing cloud droplets, small ice particles, and larger snowflakes are discussed. C1 Natl Ctr Atmospher Res, Boulder, CO 80307 USA. NOAA, Environm Res Lab, Boulder, CO 80303 USA. RP Vivekanandan, J (reprint author), Natl Ctr Atmospher Res, POB 3000, Boulder, CO 80307 USA. RI Zhang, Guifu/M-3178-2014 OI Zhang, Guifu/0000-0002-0261-2815 NR 21 TC 27 Z9 27 U1 2 U2 3 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD SEP PY 1999 VL 37 IS 5 BP 2325 EP 2334 DI 10.1109/36.789629 PN 1 PG 10 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 236YT UT WOS:000082627400021 ER PT J AU Jiang, JS Fullerton, EE Sowers, CH Inomata, A Bader, SD Shapiro, AJ Shull, RD Gornakov, VS Nikitenko, VI AF Jiang, JS Fullerton, EE Sowers, CH Inomata, A Bader, SD Shapiro, AJ Shull, RD Gornakov, VS Nikitenko, VI TI Spring magnet films SO IEEE TRANSACTIONS ON MAGNETICS LA English DT Article; Proceedings Paper CT 1999 International Magnetics Conference (INTERMAG 99) CY MAY 18-21, 1999 CL KYONGJU, SOUTH KOREA SP IEEE Magnet Soc DE permanent magnet; exchange spring; magnetic reversal; epitaxy; sputter; thin film; superlattice; SmCo ID PERMANENT-MAGNETS; ANISOTROPY; REMANENCE; BILAYERS; FE AB The properties of exchange-spring-coupled bilayer and superlattice films are highlighted for Sm-Co hard magnet (nominally Sm2Co7) and Fe or Co soft magnet layers. The hexagonal Sm-Co is grown via magnetron sputtering in a- and b-axis epitaxial orientations. In both cases the c-axis, in the film plane, is the easy axis of magnetization. Trends in coercivity with film thickness are established and related to the respective microstructures of the two orientations. The magnetization reversal process for the bilayers is examined by magnetometry and magneto-optical imaging, as well as by simulations that utilize a one-dimensional model to provide the spin configuration for each atomic layer. The Fe magnetization is pinned to that of the Sm-Co at the interface, and reversal proceeds via a progressive twisting of the Fe magnetization, The Fe demagnetization curves are reversible as expected for a spring magnet. Comparison of experiment and simulations indicates that the spring magnet behavior can be understood from the intrinsic properties of the hard and soft layers. Estimates are made of the ultimate gain in performance that can potentially be realized in this system. C1 Argonne Natl Lab, Div Sci Mat, Argonne, IL 60439 USA. NIST, Gaithersburg, MD 20899 USA. Fujitsu Ltd, Atsugi, Kanagawa, Japan. Russian Acad Sci, Inst Solid State Phys, Chernogolovka 142432, Russia. RP Jiang, JS (reprint author), Argonne Natl Lab, Div Sci Mat, Argonne, IL 60439 USA. RI Bader, Samuel/A-2995-2013; Shull, Robert/F-5971-2013; Fullerton, Eric/H-8445-2013 OI Fullerton, Eric/0000-0002-4725-9509 NR 21 TC 32 Z9 35 U1 1 U2 11 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9464 J9 IEEE T MAGN JI IEEE Trans. Magn. PD SEP PY 1999 VL 35 IS 5 BP 3229 EP 3234 DI 10.1109/20.800484 PN 2 PG 6 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA 246EM UT WOS:000083151500002 ER PT J AU Harris, VG Huang, Q Shah, VR Markandeyulu, G Rao, KVSR Huang, MQ Sirisha, K McHenry, ME AF Harris, VG Huang, Q Shah, VR Markandeyulu, G Rao, KVSR Huang, MQ Sirisha, K McHenry, ME TI Neutron diffraction and extended x-ray absorption fine structure studies of Pr-3(Fe1-xCOx)(27.5)Ti-1.5 permanent magnet compounds SO IEEE TRANSACTIONS ON MAGNETICS LA English DT Article; Proceedings Paper CT 1999 International Magnetics Conference (INTERMAG 99) CY MAY 18-21, 1999 CL KYONGJU, SOUTH KOREA SP IEEE Magnet Soc DE extended x-ray absorption fine structure; neutron diffraction; permanent magnets AB Neutron diffraction (ND) and extended x-ray absorption fine structure (EXAFS) measurements were carried out to determine the long-range and short-range structural properties of Co-substituted Pr3Fe1-xCoxTi1.5 compounds. ND refinement analysis indicates Ti atoms occupy the 4g and 4i Fe sites and Co atoms occupy, without preference, those re sites not shared with the Ti atoms, EXAFS measurements show the local environment of the Pr experiences increasing static disorder with the introduction of Co, and its coordination sphere contracts in the vicinity of those Co near neighbors. The Fe local environment remains unaffected with the introduction of Co suggesting that substitution in excess of 40% can be achieved in this structure. C1 USN, Res Lab, Washington, DC 20375 USA. NIST, Ctr Neutron Res, Gaithersburg, MD 20899 USA. Indian Inst Technol, Dept Phys, Magnetism & Magnet Mat Lab, Madras 600036, Tamil Nadu, India. Carnegie Mellon Univ, Dept Mat Sci, Pittsburgh, PA 15213 USA. RP Harris, VG (reprint author), USN, Res Lab, Washington, DC 20375 USA. RI Harris, Vincent/A-8337-2009; McHenry, Michael/B-8936-2009 NR 8 TC 20 Z9 20 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9464 J9 IEEE T MAGN JI IEEE Trans. Magn. PD SEP PY 1999 VL 35 IS 5 BP 3286 EP 3288 DI 10.1109/20.800500 PN 2 PG 3 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA 246EM UT WOS:000083151500018 ER PT J AU Pardavi-Horvath, M Swartzendruber, LJ AF Pardavi-Horvath, M Swartzendruber, LJ TI Ferromagnetic resonance relaxation in reaction milled and annealed Fe-Zn nanocomposites SO IEEE TRANSACTIONS ON MAGNETICS LA English DT Article; Proceedings Paper CT 1999 International Magnetics Conference (INTERMAG 99) CY MAY 18-21, 1999 CL KYONGJU, SOUTH KOREA SP IEEE Magnet Soc DE nanocomposites; ferromagnetic resonance; magnetic relaxation ID PARTICLES; IRON AB SQUID magnetization measurements and ferromagnetic resonance experiments have been performed at 9.77 GHz on reaction milled and subsequently annealed nanocomposites of iron particles in a ZnO matrix. The dominant contribution to the temperature and time dependence of the observed linewidth of 2.2 to 3.2 kOe arises from the spatial inhomogeneity in shape, size and interaction fields of the system. Further linewidth contributions from stress, magnetization changes, surface reconstruction are discussed. The Gilbert relaxation constant alpha is decreasing with annealing temperature from 0.45 to 0.33 at 304 C. C1 George Washington Univ, EE&CS, Washington, DC 20052 USA. NIST, Magnet Mat Grp, Gaithersburg, MD 20899 USA. RP Pardavi-Horvath, M (reprint author), George Washington Univ, EE&CS, Washington, DC 20052 USA. NR 9 TC 8 Z9 8 U1 1 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9464 J9 IEEE T MAGN JI IEEE Trans. Magn. PD SEP PY 1999 VL 35 IS 5 BP 3502 EP 3504 DI 10.1109/20.800570 PN 2 PG 3 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA 246EM UT WOS:000083151500088 ER PT J AU Pardavi-Horvath, M Vertesy, G Keszei, B Vertesy, Z McMichael, RD AF Pardavi-Horvath, M Vertesy, G Keszei, B Vertesy, Z McMichael, RD TI Switching mechanism of single domain particles in a two-dimensional array SO IEEE TRANSACTIONS ON MAGNETICS LA English DT Article; Proceedings Paper CT 1999 International Magnetics Conference (INTERMAG 99) CY MAY 18-21, 1999 CL KYONGJU, SOUTH KOREA SP IEEE Magnet Soc DE coercivity; magnetization switching; single domain particles ID 2-DIMENSIONAL ARRAY; 2-D ARRAY; DISK AB The mechanism of switching of uniaxial, single domain, single crystalline epitaxial garnet particles on a 2D square array was investigated. The anisotropy field of the sample is 2 kOe, while the gaussian switching field distribution is 280 +/- 85 Oe. The dominant contribution to the incoherent switching is from inhomogeneous internal fields and canted moments at the corners and edges, where the switching starts. The interaction field with the surrounding particles, reduced nucleation barriers at crystalline defects, thermal activation, and dynamical effects in FMR also contribute to the observed switching field and as standard deviation. C1 George Washington Univ, Dept EE&CS, Washington, DC 20052 USA. Res Inst Tech Phys & Mat Sci, H-1525 Budapest, Hungary. NIST, Magnet Mat Grp, Gaithersburg, MD 20899 USA. RP Pardavi-Horvath, M (reprint author), George Washington Univ, Dept EE&CS, Washington, DC 20052 USA. RI Vertesy, Gabor/A-5863-2011; McMichael, Robert/J-8688-2012; Vertesy, Zofia/A-9638-2011; OI McMichael, Robert/0000-0002-1372-664X NR 15 TC 9 Z9 9 U1 0 U2 3 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9464 J9 IEEE T MAGN JI IEEE Trans. Magn. PD SEP PY 1999 VL 35 IS 5 BP 3871 EP 3873 DI 10.1109/20.800692 PN 2 PG 3 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA 246EM UT WOS:000083151500210 ER PT J AU Greenhall, CA Howe, DA Percival, DB AF Greenhall, CA Howe, DA Percival, DB TI Total variance, an estimator of long-term frequency stability SO IEEE TRANSACTIONS ON ULTRASONICS FERROELECTRICS AND FREQUENCY CONTROL LA English DT Article AB Total variance is a statistical tool developed for improved estimates of frequency stability at averaging times up to one-half the test duration. As a descriptive statistic, total variance performs an exact decomposition of the sample variance of the frequency residuals into components associated with increasing averaging times. As an estimator of Allan variance, total variance has greater equivalent degrees of freedom and lesser mean square error than the standard unbiased estimator has. C1 CALTECH, Jet Prop Lab, CIT, Pasadena, CA 91109 USA. Natl Inst Stand & Technol, Div Time & Frequency, Boulder, CO 80303 USA. Univ Washington, Appl Phys Lab, Seattle, WA 98195 USA. MathSoft Inc, Seattle, WA 98195 USA. RP Greenhall, CA (reprint author), CALTECH, Jet Prop Lab, CIT, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 17 TC 54 Z9 58 U1 0 U2 5 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0885-3010 J9 IEEE T ULTRASON FERR JI IEEE Trans. Ultrason. Ferroelectr. Freq. Control PD SEP PY 1999 VL 46 IS 5 BP 1183 EP 1191 DI 10.1109/58.796124 PG 9 WC Acoustics; Engineering, Electrical & Electronic SC Acoustics; Engineering GA 245RK UT WOS:000083121800014 PM 18244312 ER PT J AU Downey, LL Tice, DM AF Downey, LL Tice, DM TI A usability case study using TREC and ZPRISE SO INFORMATION PROCESSING & MANAGEMENT LA English DT Article AB This paper examines the challenges involved in conducting an informal usability case study based on the introduction of a new information retrieval system to experienced users. We present a summary of activities performed during two iterations of usability testing and describe our analysis methodology. This methodology incorporates several grouping and prioritizing methods which provide one of the major contributions of the work. During the course of the case study, we learned some valuable lessons which were specific to the Text REtrieval Conference (TREC). The TREC-specific lessons learned led to recommendations for changes in the TREC topic development and assessment tasks. Results of the study include lessons learned about both the users and the testing techniques (Hoffman & Downey, 1997). (C) 1999 Published by Elsevier Science Ltd. All rights reserved. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Downey, LL (reprint author), Natl Inst Stand & Technol, 100 Bur Dr,Stop 8940, Gaithersburg, MD 20899 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 0306-4573 J9 INFORM PROCESS MANAG JI Inf. Process. Manage. PD SEP PY 1999 VL 35 IS 5 BP 589 EP 603 DI 10.1016/S0306-4573(99)00013-8 PG 15 WC Computer Science, Information Systems; Information Science & Library Science SC Computer Science; Information Science & Library Science GA 235WL UT WOS:000082565800001 ER PT J AU Telles, EM Zink, LR Evenson, KM AF Telles, EM Zink, LR Evenson, KM TI New FIR laser lines and frequency measurements of CD3OD SO INTERNATIONAL JOURNAL OF INFRARED AND MILLIMETER WAVES LA English DT Article ID METHANOL AB The isotopomer of methanol, CD3OD, was optically pumped by a cw CO2 laser resulting in 53 new far-infrared (FIR) laser lines. The wavelengths are in the range 42.9 mu m to 189.9 mu m with the majority below 100 mu m. Ten different CO2 lines were used for the tirst time to pump CD3OD yielding new FIR laser lines. Some of the CO2 pump lines belong to the hot-bands and sequence-bands of CO2 in the 10 mu m region. The frequency was measured for 40 FIR laser lines in the range 1.5 THz to 6.9 THz, 32 of which were new laser lines. C1 Natl Inst Stand & Technol, Div Time & Frequency, Boulder, CO 80303 USA. RP Telles, EM (reprint author), Natl Inst Stand & Technol, Div Time & Frequency, 325 Broadway, Boulder, CO 80303 USA. NR 8 TC 1 Z9 1 U1 0 U2 5 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0195-9271 J9 INT J INFRARED MILLI JI Int. J. Infrared Millimeter Waves PD SEP PY 1999 VL 20 IS 9 BP 1631 EP 1645 DI 10.1023/A:1021738704734 PG 15 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA 233YB UT WOS:000082453800001 ER PT J AU Koshy, P Ives, LK Jahanmir, S AF Koshy, P Ives, LK Jahanmir, S TI Simulation of diamond-ground surfaces SO INTERNATIONAL JOURNAL OF MACHINE TOOLS & MANUFACTURE LA English DT Article DE diamond grinding; simulation; surface finish; wheel topography ID PROFILES AB State-of-the-art models available for predicting the characteristics of diamond-ground surfaces entail digitization of wheel topography which limits their practical utility. This paper presents a geometric simulation of surface generation in diamond grinding, that utilizes wheel topography data obtained from simulated three-dimensional structure of the diamond grinding wheel. Simulation results are validated by surface grinding experiments on a variety of materials that exhibit different material removal mechanisms, with the roughness parameters R-a and R-t, the autocorrelation function and the fractal dimension as the comparison indices. A parametric study on the effect of various grinding parameters on surface finish is also reported, with particular emphasis on identifying and minimizing process-inherent variability. Published by Elsevier Science Ltd. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Jahanmir, S (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NR 29 TC 22 Z9 24 U1 0 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0890-6955 J9 INT J MACH TOOL MANU JI Int. J. Mach. Tools Manuf. PD SEP PY 1999 VL 39 IS 9 BP 1451 EP 1470 DI 10.1016/S0890-6955(99)00002-4 PG 20 WC Engineering, Manufacturing; Engineering, Mechanical SC Engineering GA 202JG UT WOS:000080648100008 ER PT J AU Kiselev, SB Perkins, RA Huber, ML AF Kiselev, SB Perkins, RA Huber, ML TI Transport properties of refrigerants R32, R125, R134a, and R125+R32 mixtures in and beyond the critical region SO INTERNATIONAL JOURNAL OF REFRIGERATION-REVUE INTERNATIONALE DU FROID LA English DT Article DE refrigerant; R32; R125; R134a; thermal conductivity; thermal diffusivity ID EXTENDED CRITICAL REGION; THERMODYNAMIC PROPERTIES; THERMAL-CONDUCTIVITY; CROSSOVER-BEHAVIOR; VISCOSITY; PENTAFLUOROETHANE; DIFLUOROMETHANE; COEFFICIENTS; DIFFUSIVITY; EQUATIONS AB A practical representation for the transport coefficients of pure refrigerants R32, R125, R134a, and R125 + R32 mixtures is presented which is valid in the vapor-liquid critical region. The crossover expressions for the transport coefficients incorporate scaling laws near the critical point and are transformed to regular background values far away from the critical point. The regular background parts of the transport coefficients of pure refrigerants are obtained from independently fitting pure fluid data. For the calculation of the background contributions of the transport coefficients in binary mixtures, corresponding-states correlations are used. The transport property model is compared with thermal conductivity and thermal diffusivity data for pure refrigerants, and with thermal conductivity data for R125 + R32 mixtures. The average relative deviations between the calculated values of the thermal conductivity and experimental data are less than 4-5% at densities rho greater than or equal to 0.1 rho(c) and temperatures up to T = 2T(c). (C) 1999 Elsevier Science Ltd and IIR. All rights reserved. C1 Natl Inst Stand & Technol, Phys & Chem Properties Div, Boulder, CO 80303 USA. RP Kiselev, SB (reprint author), Colorado Sch Mines, Dept Chem Engn & Petr Refining, Golden, CO 80401 USA. OI Perkins, Richard/0000-0002-8526-6742 NR 38 TC 17 Z9 17 U1 0 U2 4 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0140-7007 J9 INT J REFRIG JI Int. J. Refrig.-Rev. Int. Froid PD SEP PY 1999 VL 22 IS 6 BP 509 EP 520 DI 10.1016/S0140-7007(99)00007-9 PG 12 WC Thermodynamics; Engineering, Mechanical SC Thermodynamics; Engineering GA 225UU UT WOS:000081984100007 ER PT J AU Duarte-Garza, HA Magee, JW AF Duarte-Garza, HA Magee, JW TI Subatmospheric vapor pressures for fluoromethane (R41), 1,1-difluoroethane (R152a), and 1,1,1-trifluoroethane (R143a) evaluated from internal-energy measurements SO INTERNATIONAL JOURNAL OF THERMOPHYSICS LA English DT Article DE 1,1-difluoroethane; fluoromethane; internal energy; refrigerants; 1,1,1-trifluoroethane; triple point; two-phase region; vapor pressure ID THERMODYNAMIC PROPERTIES; STATE; EQUATION AB Vapor pressures were evaluated from measured internal-energy changes Delta U-(2) in the vapor + liquid two-phase region. The method employed a thermodynamic relationship between the derivative quantity (partial derivative U-(2)/partial derivative V)(T), the vapor pressure p(sigma), and its temperature derivative (partial derivative p/partial derivative T)(sigma). This method was applied at temperatures between the triple point and the normal boiling point of three substances: fluoromethane (R41), 1,1-difluoroethane (R152a), and 1,1,1-trifluoroethane (R143a). In the case of R41, vapor pressures up to 1 MPa were calculated to validate the technique at higher pressures. For R152a, the calculated vapor pressure at the triple-point temperature differed from a direct experimental measurement by less than the claimed uncertainty (5 Pa) of the measurement. The calculated vapor pressures for R41 helped to resolve discrepancies in several published vapor pressure sources. Agreement with experimentally measured vapor pressures for R152a and for R143a near the normal boiling point (101.325 kPa) was within the experimental uncertainty of approximately 0.04 kPa (0.04%) for the published measurements. C1 Natl Inst Stand & Technol, Phys & Chem Properties Div, Chem Sci & Technol Lab, Boulder, CO 80303 USA. Texas A&M Univ, Kingsville, TX 78363 USA. RP Magee, JW (reprint author), Natl Inst Stand & Technol, Phys & Chem Properties Div, Chem Sci & Technol Lab, 325 Broadway, Boulder, CO 80303 USA. RI Magee, Joseph/A-8496-2009 OI Magee, Joseph/0000-0002-9312-8593 NR 21 TC 9 Z9 11 U1 0 U2 3 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0195-928X J9 INT J THERMOPHYS JI Int. J. Thermophys. PD SEP PY 1999 VL 20 IS 5 BP 1467 EP 1481 DI 10.1023/A:1021493106087 PG 15 WC Thermodynamics; Chemistry, Physical; Mechanics; Physics, Applied SC Thermodynamics; Chemistry; Mechanics; Physics GA 266YN UT WOS:000084328000010 ER PT J AU Mursalov, BA Abdulagatov, IM Dvoryanchikov, VI Kamalov, AN Kiselev, SB AF Mursalov, BA Abdulagatov, IM Dvoryanchikov, VI Kamalov, AN Kiselev, SB TI Isochoric heat capacity of heavy water at subcritical and supercritical conditions SO INTERNATIONAL JOURNAL OF THERMOPHYSICS LA English DT Article DE coexistence curve; critical point; crossover equation of state; heavy water; isochoric heat capacity; water ID CONSTANT VOLUME; CRITICAL-POINT; PURE WATER; PROPANE; REGION; H2O AB The heat capacity of heavy water was measured in the temperature range from 294 to 746 K and at densities between 52 and 1105 kg.m(-3) using a high-temperature, high-pressure adiabatic calorimeter. The measurements were performed at 14 liquid and 9 vapor densities between 52 and 1105 kg.m(-3). Uncertainties of the measurements are estimated to be within 3% for vapor isochores and 1.5% for the liquid isochores. In the region of the immediate vicinity of the critical point (0.97 less than or equal to T/T-c less than or equal to 1.03 and 0.75 less than or equal to rho/rho(c) less than or equal to 1.25), the uncertainty is 4.5%. The original C-V data were corrected and converted to the new ITS-90 temperature scale. A parametric crossover equation of state was used to represent the isochoric heat capacity measurements of heavy water in the extended critical region, 0.8 less than or equal to T/T-c less than or equal to 1.5 and 0.35 less than or equal to rho/rho(c) less than or equal to 1.65. The liquid and vapor one- and two-phase isochoric heat capacities, temperatures, and saturation densities were extracted from experimental data for each measured isochore. Most of the experimental data are compared with the Hill equation of state, and the overall statistics of deviations between experimental data and the equation of state are given. C1 Russian Acad Sci, Inst Geothermal Problems, Dagestan Sci Ctr, Makhachkala 367030, Dagestan, Russia. Natl Inst Stand & Technol, Phys & Chem Properties Div, Boulder, CO 80303 USA. RP Abdulagatov, IM (reprint author), Russian Acad Sci, Inst Geothermal Problems, Dagestan Sci Ctr, Kalinina 39-A, Makhachkala 367030, Dagestan, Russia. NR 24 TC 27 Z9 27 U1 0 U2 5 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0195-928X J9 INT J THERMOPHYS JI Int. J. Thermophys. PD SEP PY 1999 VL 20 IS 5 BP 1497 EP 1528 DI 10.1023/A:1021497206995 PG 32 WC Thermodynamics; Chemistry, Physical; Mechanics; Physics, Applied SC Thermodynamics; Chemistry; Mechanics; Physics GA 266YN UT WOS:000084328000012 ER PT J AU Povodyrev, AA Anisimov, MA Sengers, JV Marshall, WL Sengers, JMHL AF Povodyrev, AA Anisimov, MA Sengers, JV Marshall, WL Sengers, JMHL TI Critical locus of aqueous solutions of sodium chloride SO INTERNATIONAL JOURNAL OF THERMOPHYSICS LA English DT Article DE aqueous salt solutions; critical locus; critical temperatures; ionic fluids; sodium chloride solutions ID SYSTEM NACL-H2O; PHASE-EQUILIBRIA; CRITICAL REGION; CRITICAL LINES; VAPOR-LIQUID; BEHAVIOR; 500-DEGREES-C; ELECTROLYTES; TEMPERATURES; CROSSOVER AB Experimental data reported in the literature indicate a strong dependence of the critical temperature of aqueous solutions of sodium chloride on salt concentration, especially in the limit of pure water. Critical pressures and densities also show strong dependences on salt concentration. We propose a new set of equations for the critical locus and compare the results with evaluations reported previously by a number of investigators. The new equations yield a better description of the experimental data from the limit of pure water to the highest salt concentration for which data are available (0.3 mass fraction of sodium chloride). C1 Univ Maryland, Inst Phys Sci & Technol, College Pk, MD 20742 USA. Univ Maryland, Dept Chem Engn, College Pk, MD 20742 USA. Natl Inst Stand & Technol, Phys & Chem Properties Div, Gaithersburg, MD 20899 USA. Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA. RP Anisimov, MA (reprint author), Univ Maryland, Inst Phys Sci & Technol, College Pk, MD 20742 USA. NR 27 TC 15 Z9 15 U1 1 U2 5 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0195-928X J9 INT J THERMOPHYS JI Int. J. Thermophys. PD SEP PY 1999 VL 20 IS 5 BP 1529 EP 1545 DI 10.1023/A:1021449323833 PG 17 WC Thermodynamics; Chemistry, Physical; Mechanics; Physics, Applied SC Thermodynamics; Chemistry; Mechanics; Physics GA 266YN UT WOS:000084328000013 ER PT J AU Chen, DR Pui, DYH Mulholland, GW Fernandez, M AF Chen, DR Pui, DYH Mulholland, GW Fernandez, M TI Design and testing of an aerosol sheath inlet for high resolution measurements with a DMA SO JOURNAL OF AEROSOL SCIENCE LA English DT Article ID DIFFERENTIAL MOBILITY ANALYZER; BROWNIAN DIFFUSION; CALIBRATION; PARTICLES AB A modified aerosol/sheath inlet was designed for a differential mobility analyzer (DMA) for high resolution measurements based on field model calculations which include fluid flow, electric field, and convective/diffusive transport. To avoid the predicted flow recirculation for the current inlet design at an aerosol-to-sheath flow ratio of 0.05, the slit width is reduced and aerodynamically shaped so that the sheath velocity and aerosol velocity more nearly match. Numerical results are presented comparing the fluid flow of the old and new inlet. Problems associated with the old inlet include: flow unsteadiness at a flow ratio of 0.025, voltage shift at the peak particle concentration as a function of the flow ratio, and the historical observation that, while performing tandem differential mobility analyzer measurements (TDMA), the voltage applied on the second DMA for the peak particle concentration is higher than that for the first. Measurements demonstrate that all these problems are reduced or eliminated with the new inlet design. The TDMA measurements include flow ratios of 0.1, 0.05, 0.025 and 0.0125 at sheath flows of 166 and 333 cm(3) s(-1) (10 and 20 l min(-1)). The challenge of performing measurements at these low flow ratios will be discussed including flow calibration, flow matching, and pressure monitoring. The new inlet is applied to the measurement of the National Institute of Standards and Technology 0.1 mu m Standard Reference Material 1963, and it is shown that the DMA can accurately measure the standard deviation of this narrowly distributed aerosol (sigma/D-p = 0.02). (C) 1999 Published by Elsevier Science Ltd. All rights reserved. C1 Univ Minnesota, Particle Technol Lab, Dept Mech Engn, Minneapolis, MN 55455 USA. NIST, Gaithersburg, MD 20899 USA. RP Pui, DYH (reprint author), Univ Minnesota, Particle Technol Lab, Dept Mech Engn, 111 Church St, Minneapolis, MN 55455 USA. NR 10 TC 21 Z9 21 U1 2 U2 7 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0021-8502 J9 J AEROSOL SCI JI J. Aerosol. Sci. PD SEP PY 1999 VL 30 IS 8 BP 983 EP 999 DI 10.1016/S0021-8502(98)00767-8 PG 17 WC Engineering, Chemical; Engineering, Mechanical; Environmental Sciences; Meteorology & Atmospheric Sciences SC Engineering; Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA 217CB UT WOS:000081481000003 ER PT J AU Weaver, LA Lundstrom, RC Colbert, AA AF Weaver, LA Lundstrom, RC Colbert, AA TI Identification of shark species by polyacrylamide gel isoelectric focusing of sarcoplasmic proteins SO JOURNAL OF AOAC INTERNATIONAL LA English DT Article ID TISSUE PROTEINS AB Isoelectric focusing of muscle proteins is a fast and highly reproducible technique that has been used to identify fish species. Application of isoelectric focusing of sarcoplasmic proteins is described for identification of shark species. Sarcoplasmic protein patterns from muscle tissue of single individuals from 26 shark species and multiple individuals from 2 of the 26 shark species are shown on 1 mm thick polyacrylamide gels. Eight of these species showed pattern polymorphisms in major and minor bands; however, no individual within a species displayed the same protein pattern as that in any other species. Protein banding patterns of each species were visually distinguishable, and patterns generated on the basis of defined parameters were analyzed by a computer to obtain isoelectric points of bands, to produce schematic representations of banding patterns, and to distinguish between species-specific patterns, Isoelectric focusing appears to be an excellent method for identifying sharks. Additionally, isoelectric focusing of muscle proteins is readily applicable as a forensic tool to identify the species of shark samples received as evidence for law enforcement actions supporting shark fishery management plans. C1 Natl Ocean Serv, US Dept Commerce, NOAA, Charleston, SC 29412 USA. RP Weaver, LA (reprint author), Natl Ocean Serv, US Dept Commerce, NOAA, 219 Ft Johnson Rd, Charleston, SC 29412 USA. NR 21 TC 7 Z9 7 U1 0 U2 0 PU AOAC INTERNATIONAL PI GAITHERSBURG PA 481 NORTH FREDRICK AVE, STE 500, GAITHERSBURG, MD 20877-2504 USA SN 1060-3271 J9 J AOAC INT JI J. AOAC Int. PD SEP-OCT PY 1999 VL 82 IS 5 BP 1163 EP 1170 PG 8 WC Chemistry, Analytical; Food Science & Technology SC Chemistry; Food Science & Technology GA 239UU UT WOS:000082788700017 ER PT J AU Zhou, BB Xu, Q AF Zhou, BB Xu, Q TI Computing surface fluxes from Mesonet data SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID RADIATION BALANCE SYSTEMS; HAPEX-MOBILHY; LAND; LAYER; MODELS; ENERGY; PARAMETERIZATION; VEGETATION; MOISTURE; HEAT AB By using air-vegetation-soil layer coupled model equations as weak constraints, a variational method is developed to compute sensible and latent heat fluxes from conventional observations obtained at meteorological surface stations. This method also retrieves the top soil layer water content (daytime only) and the surface skin temperature as by-products. The method is applied to Oklahoma Mesonet data collected in the summer of 1995. Fluxes computed for selected Mesonet stations are verified against those obtained by the surface energy and radiation balance system at Atmospheric Radiation Measurement (ARM) Cloud and Radiation Testbed (CART) sites closest to the selected Mesonet stations. The retrieved values of soil water content are also compared with the direct measurements at the closest ARM CART stations. With data provided by the dense Mesonet, the method is shown to be useful in deriving the mesoscale distributions and temporal variabilities of surface fluxes, soil water content, and skin temperature. The method is unique in that it provides an additional means to derive flux fields directly from conventional surface observations. C1 Univ Oklahoma, Cooperat Inst Mesoscale Meteorolog Stud, Norman, OK 73019 USA. USN, Res Lab, Monterey, CA USA. RP Natl Severe Storms Lab, Norman, OK 73069 USA. EM qxu@nssl.noaa.gov NR 27 TC 7 Z9 7 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8763 J9 J APPL METEOROL JI J. Appl. Meteorol. PD SEP PY 1999 VL 38 IS 9 BP 1370 EP 1383 DI 10.1175/1520-0450(1999)038<1370:CSFFMD>2.0.CO;2 PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 240NY UT WOS:000082833100008 ER PT J AU Bloss, P DeReggi, AS Glasel, HJ Hartmann, E Hirsch, D Schafer, H AF Bloss, P DeReggi, AS Glasel, HJ Hartmann, E Hirsch, D Schafer, H TI Polarization distribution in ceramic-polymer nanocomposites SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID TITANATE THIN-FILMS; NANOCRYSTALLINE BATIO3; DEPOSITION; EQUATIONS; PARTICLES; PROFILES AB We report pyroelectric responsivity versus depth profiles in nanocomposites of powdered barium titanate and tripropylene glycol diacrylate obtained by using the thermal pulse (TP) method. The ceramic nanopowder (mean particle size 270 nm) was prepared by combined solid-state polymerization and pyrolysis of a metallo-organic precursor. Films of powder/monomer dispersion (thickness similar to 30 mu m) were cured by irradiation with an electron beam (energy 140 keV, dose 80 kGy). The observation of a TP response after electron beam curing (EBC) indicates the appearance of a poling electric field as an effect of the EBC. The polarization depth profiles were studied for different filler contents. The composites show potential promise for piezo and pyroelectric sensors applications and for charge storage in microelectronics. (C) 1999 American Institute of Physics. [S0021-8979(99)03417-9]. C1 Inst Surface Modificat, D-04318 Leipzig, Germany. Natl Inst Stand & Technol, Div Polymers, Gaithersburg, MD 20899 USA. Univ Nijmegen, NSR Ctr, HF NMR Facil, NL-6525 Nijmegen, Netherlands. Leipzig Gemeinnut Gesell mbH, Kunststoff Zentrum, D-04229 Leipzig, Germany. RP Hartmann, E (reprint author), Inst Surface Modificat, Permoserstr 15, D-04318 Leipzig, Germany. NR 27 TC 5 Z9 5 U1 2 U2 6 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD SEP 1 PY 1999 VL 86 IS 5 BP 2712 EP 2718 DI 10.1063/1.371115 PG 7 WC Physics, Applied SC Physics GA 227GV UT WOS:000082073000054 ER PT J AU Jordan, CE Stranick, SJ Richter, LJ Cavanagh, RR AF Jordan, CE Stranick, SJ Richter, LJ Cavanagh, RR TI Removing optical artifacts in near-field scanning optical microscopy by using a three-dimensional scanning mode SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID TIP ARTIFACTS; SHEAR FORCE; RESOLUTION; SPECTROSCOPY; CONTRAST AB We demonstrate a method of acquiring near-field scanning optical microscopy data that allow for the construction of three different types of images from one data set: topographic, constantgap, and constant-height. This data set includes the topographic features of the surface and the optical response at various heights above the sample surface. Comparisons are made between the images recorded in this format and both conventional, constant-gap mode images, and pseudoconstant-height mode images constructed using a single retraction curve. Z-motion artifacts are identified by analyzing the optical intensity for a given image as a function of the sample topography. Using this procedure it is shown that significant z-motion artifacts exist in the constant-gap images of gold particles immobilized on a glass slide. These artifacts are avoided by constructing constant-height images. [S0021-8979(99)07517-9]. C1 Natl Inst Stand & Technol, Surface & Microanal Sci Div, Gaithersburg, MD 20899 USA. RP Stranick, SJ (reprint author), Natl Inst Stand & Technol, Surface & Microanal Sci Div, Gaithersburg, MD 20899 USA. RI Richter, Lee/N-7730-2016 OI Richter, Lee/0000-0002-9433-3724 NR 29 TC 21 Z9 21 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD SEP 1 PY 1999 VL 86 IS 5 BP 2785 EP 2789 DI 10.1063/1.371126 PG 5 WC Physics, Applied SC Physics GA 227GV UT WOS:000082073000065 ER PT J AU Dragnea, B Preusser, J Schade, W Leone, SR Hinsberg, WD AF Dragnea, B Preusser, J Schade, W Leone, SR Hinsberg, WD TI Transmission near-field scanning microscope for infrared chemical imaging SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID OPTICAL MICROSCOPE; SPECTROSCOPY; PROBE AB We report transmission infrared near-field scanning microscopy (IR-NSOM) imaging of chemically amplified photoresist polymers patterned by ultraviolet exposure. Chemical specificity was attained using infrared wavelengths tuned to the 3 mu m OH stretch absorption band of the polymer, a band sensitive to the chemical changes characteristic of the lithographic photochemical process of this material. Contrast mechanisms are discussed together with the IR-NSOM specifics, such as the fabrication of an infrared near-field probe with high throughput, which lead to an attainable resolution of lambda/10 and a transmission sensitivity of 1%. (C) 1999 American Institute of Physics. [S0021-8979(99)05917-4]. C1 Natl Inst Stand & Technol, Joint Inst Lab Astrophys, Dept Chem, Div Quantum Phys, Boulder, CO 80309 USA. Natl Inst Stand & Technol, Joint Inst Lab Astrophys, Dept Phys, Boulder, CO 80309 USA. IBM Corp, Almaden Res Ctr, San Jose, CA 95120 USA. RP Natl Inst Stand & Technol, Joint Inst Lab Astrophys, Dept Chem, Div Quantum Phys, Boulder, CO 80309 USA. EM srl@jila.colorado.edu NR 19 TC 39 Z9 39 U1 0 U2 7 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 0021-8979 EI 1089-7550 J9 J APPL PHYS JI J. Appl. Phys. PD SEP 1 PY 1999 VL 86 IS 5 BP 2795 EP 2799 DI 10.1063/1.371127 PG 5 WC Physics, Applied SC Physics GA 227GV UT WOS:000082073000067 ER PT J AU Landsberg, JH Balazs, GH Steidinger, KA Baden, DG Work, TM Russell, DJ AF Landsberg, JH Balazs, GH Steidinger, KA Baden, DG Work, TM Russell, DJ TI The potential role of natural tumor promoters in marine turtle fibropapillomatosis SO JOURNAL OF AQUATIC ANIMAL HEALTH LA English DT Article ID OKADAIC ACID CLASS; PROTEIN PHOSPHATASE INHIBITOR; CHELONIA-MYDAS L; GREEN TURTLE; HAWAIIAN-ISLANDS; CALYCULIN-A; MOUSE SKIN; CELL-TRANSFORMATION; CHEMICAL COFACTORS; PROROCENTRUM-LIMA AB Fibropapillomatosis (FP) in green turtles Chelonia mydas is a debilitating, neoplastic disease that has reached worldwide epizootic levels. The etiology of FP is unknown but has been linked to oncogenic viruses. Toxic benthic dinoflagellates (Prorocentrum spp.) are not typically considered tumorigenic agents, yet they have a worldwide distribution and produce a tumor promoter, okadaic acid (OA). Prorocentrum spp. are epiphytic on macroalgae and seagrasses that are normal components of green turtle diets. Here we show that green turtles in the Hawaiian Islands consume Prorocentrum and that high-risk FP areas are associated with areas where P. lima and P. concavum are both highly prevalent and abundant. The presence of presumptive OA in the tissues of Hawaiian green turtles further suggests exposure and a potential role for this tumor promoter in the etiology of FP. C1 Florida Marine Res Inst, Florida Fish & Wildlife Conservat Commiss, St Petersburg, FL 33701 USA. Natl Marine Fisheries Serv, Honolulu Lab, SW Fisheries Sci Ctr, Honolulu, HI 96822 USA. Univ Miami, Rosenstiel Sch Marine & Atmospher Sci, Marine & Freshwater Biomed Sci Ctr, Natl Inst Environm Hlth Sci, Miami, FL 33149 USA. US Geol Survey, Biol Resources Div, Natl Wildlife Hlth Ctr, Honolulu Field Stn, Honolulu, HI 96850 USA. Univ Alaska SE, Dept Biol, Juneau, AK 99801 USA. RP Landsberg, JH (reprint author), Florida Marine Res Inst, Florida Fish & Wildlife Conservat Commiss, 100 8th Ave SE, St Petersburg, FL 33701 USA. EM landsberg.j@epic7.dep.state.fl.us RI Work, Thierry/F-1550-2015 OI Work, Thierry/0000-0002-4426-9090 NR 90 TC 40 Z9 43 U1 0 U2 9 PU TAYLOR & FRANCIS INC PI PHILADELPHIA PA 325 CHESTNUT ST, SUITE 800, PHILADELPHIA, PA 19106 USA SN 0899-7659 J9 J AQUAT ANIM HEALTH JI J. Aquat. Anim. Health PD SEP PY 1999 VL 11 IS 3 BP 199 EP 210 DI 10.1577/1548-8667(1999)011<0199:TPRONT>2.0.CO;2 PG 12 WC Fisheries; Veterinary Sciences SC Fisheries; Veterinary Sciences GA 316TT UT WOS:000087184700001 ER PT J AU Aguirre, AA Spraker, TR Chaves, A Du Toit, L Eure, W Balazs, GH AF Aguirre, AA Spraker, TR Chaves, A Du Toit, L Eure, W Balazs, GH TI Pathology of fibropapillomatosis in Olive Ridley turtles Lepidochelys olivacea nesting in Costa Rica SO JOURNAL OF AQUATIC ANIMAL HEALTH LA English DT Article ID GREEN TURTLES; CHELONIA-MYDAS; HAWAIIAN-ISLANDS AB Fibropapillomatosis (FP) is a neoplastic disease that primarily affects green turtles Chelonia mydas in epidemic proportions worldwide. Although several infectious agents (herpesvirus, retrovirus, and papillomavirus) have been associated with the condition, the etiologic agent has not been isolated or characterized. Recently, FP has been reported in other sea turtle species including confirmed cases in loggerhead turtles Caretta caretta in Florida and field observations in olive ridley turtles Lepidochelys olivacea in the Pacific coasts elf Mexico and Costa Rica. Skin and tumor specimens were collected from 72 olive ridley turtles nesting in Ostional Wildlife Refuge, Costa Pica, between July and September 1997. In all, 50 tumor biopsies were examined from 25 of the affected turtles. In addition, six biopsies were examined from five turtles that did not have visible masses and served as controls. Grossly, masses were 25 mm or less in diameter, white to gray, smooth to verruciform, raised tumors of the integument of the neck and flippers. Histologically, 42 of 50 were diagnosed as fibropapillomas and eight were classified as chronic active dermatitis and not tumors. Twenty of 42 fibropapillomas were in stages of regression and 9 of the remaining 22 tumors had histological changes that suggested early degeneration within the tumor. During field surveys based cn gross lesions, prevalences of 1-10% have been reported in this nesting population. This is considered the first histopathologic confirmation of FP in olive ridley turtles. C1 Univ Hawaii, Joint Inst Marine & Atmospher Res, Honolulu, HI 96822 USA. Colorado State Univ, State Vet Diagnost Lab, Ft Collins, CO 80523 USA. Douglas Robinson Marine Turtle Res Ctr, Ostional, Costa Rica. Natl Marine Fisheries Serv, SW Fisheries Sci Ctr, Honolulu Lab, Honolulu, HI 96822 USA. RP Aguirre, AA (reprint author), Tufts Univ, Sch Vet Med, Wildlife Clin, 200 Westboro Rd, N Grafton, MA 01536 USA. NR 19 TC 10 Z9 11 U1 0 U2 9 PU AMER FISHERIES SOC PI BETHESDA PA 5410 GROSVENOR LANE SUITE 110, BETHESDA, MD 20814-2199 USA SN 0899-7659 J9 J AQUAT ANIM HEALTH JI J. Aquat. Anim. Health PD SEP PY 1999 VL 11 IS 3 BP 283 EP 289 DI 10.1577/1548-8667(1999)011<0283:POFIOR>2.0.CO;2 PG 7 WC Fisheries; Veterinary Sciences SC Fisheries; Veterinary Sciences GA 316TT UT WOS:000087184700010 ER PT J AU Duarte-Garza, HA Magee, JW AF Duarte-Garza, HA Magee, JW TI Isochoric p-rho-T and heat capacity C-v measurements on {xC(3)H(8)+(1-x)i-C4H10, x approximate to 0.7, 0.3} from 200 to 400 K at pressures to 35 MPa SO JOURNAL OF CHEMICAL AND ENGINEERING DATA LA English DT Article ID ORTHOBARIC LIQUID DENSITIES; PENTAFLUOROETHANE R125; DIELECTRIC-CONSTANTS; DIFLUOROMETHANE R32; ISOBUTANE; MIXTURES; NITROGEN; PROPANE; VOLUME; 300-K AB The p-rho-T relationships and constant volume heat capacity C-v were measured for binary hydrocarbon mixtures containing propane (C3H8) and isobutane (i-C4H10). Temperatures ranged from 200 K to 400 K for p-rho-T and from 203 K to 342 K for C-v with pressures up to 35 MPa for both measurements. Measurements of p-rho-T and C-v were conducted on liquid samples with the mole fraction compositions {xC(3)H(8) + (1 - x)i-C4H10} for x = 0.7006 and x: = 0.2979. Determinations of saturated-liquid densities were made by extrapolating each isochore to the saturated-liquid pressure and determining the temperature and density at the intersection. Published p-rho-T data are in good agreement with this study. For the p-rho-T apparatus, the uncertainty of the temperature is 0.03 K, and for pressure it is 0.01% at p > 3 MPa and 0.05% at p < 3 MPa. The principal source of uncertainty in density is the cell volume (similar to 28.5 cm(3)) with a standard uncertainty of 0.003 cm(3). When all components of experimental uncertainty are considered, the expanded relative uncertainty (with a coverage factor k = 2 and thus a two-standard-deviation estimate) of the density measurements is estimated to be 0.05%. For the C-v apparatus, the uncertainty is 0.002 K for the temperature rise and 0.2% for the change-of-volume work, which is the principal source of uncertainty. The expanded relative uncertainty of the heat capacity measurements is estimated to be 0.7%. C1 Natl Inst Stand & Technol, Div Phys & Chem Properties, Chem Sci & Technol Lab, Boulder, CO 80303 USA. RP Magee, JW (reprint author), Natl Inst Stand & Technol, Div Phys & Chem Properties, Chem Sci & Technol Lab, 325 Broadway, Boulder, CO 80303 USA. RI Magee, Joseph/A-8496-2009 OI Magee, Joseph/0000-0002-9312-8593 NR 20 TC 12 Z9 12 U1 0 U2 5 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0021-9568 J9 J CHEM ENG DATA JI J. Chem. Eng. Data PD SEP-OCT PY 1999 VL 44 IS 5 BP 1048 EP 1054 DI 10.1021/je990090r PG 7 WC Thermodynamics; Chemistry, Multidisciplinary; Engineering, Chemical SC Thermodynamics; Chemistry; Engineering GA 238YU UT WOS:000082743000035 ER PT J AU Enfield, DB Mestas-Nunez, AM AF Enfield, DB Mestas-Nunez, AM TI Multiscale variabilities in global sea surface temperatures and their relationships with tropospheric climate patterns SO JOURNAL OF CLIMATE LA English DT Article ID OCEAN-ATMOSPHERE MODEL; NORTH PACIFIC; EL-NINO; INTERDECADAL VARIABILITY; GEOPOTENTIAL HEIGHT; SOUTH-ATLANTIC; SST ANOMALIES; HEAT-FLUX; CIRCULATION; OSCILLATION AB El Nino-Southern Oscillation (ENSO) is a global phenomenon with significant phase propagation within and between basins. This is captured and described in the first mode of a complex empirical orthogonal function (CEOF) analysis of sea surface temperature anomaly (SSTA) from the midnineteenth century through 1991. The global ENSO from the SSTA data, plus a linear trend everywhere, are subsequently removed in order to consider other global modes of variability uncontaminated by the intra- and interbasin effects of ENSO. An ordinary CEOF analysis of the SSTA residuals reveals three non-ENSO modes of low-frequency variability that are related to slow oceanic and climate signals described in the literature. The first two modes have decadal to multidecadal timescales with high loadings in the Pacific. They bear some spatial similarities to the ENSO pattern but are broader, more intense at high latitudes, and differ in the time domain. A CEOF analysis confirms that they are not merely the phase-related components of a single mode and that all three modes are without significant phase propagation. The third mode is a multidecadal signal with maximal realization in the extratropical North Atlantic southeast of Greenland. It is consistent with studies that have documented connections between North Atlantic SSTA and the tropospheric North Atlantic Oscillation (NAO). All three SSTA modes have midtropospheric associations related to previously classified Northern Hemisphere teleconnection patterns. The relationships between SSTA modes and tropospheric patterns are consistent with the ocean-atmosphere interactions discussed in previous studies to explain low-frequency climate oscillations in the North Pacific and North Atlantic sectors. The first three leading modes of non-ENSO SSTA are most related, to the tropospheric patterns of the Pacific North American, the North Pacific, and the Arctic oscillations (AO), respectively. The 500-hPa pattern associated with the third SSTA mode also bears similarities to the NAO in its Atlantic sector. This North Atlantic mode has a region of high, positive SSTA loadings in the Gulf of Alaska, which appear to be connected to the North Atlantic SSTA by a tropospheric bridge effect in the AO. C1 NOAA, Atlantic Oceanog & Meteorol Lab, Miami, FL 33149 USA. Univ Miami, Cooperat Inst Marine & Atmospher Studies, Miami, FL 33152 USA. RP Enfield, DB (reprint author), NOAA, Atlantic Oceanog & Meteorol Lab, 4301 Rickenbacker Causeway, Miami, FL 33149 USA. RI Mestas-Nunez, Alberto/A-1427-2012; Enfield, David/I-2112-2013 OI Mestas-Nunez, Alberto/0000-0002-3546-3668; Enfield, David/0000-0001-8107-5079 NR 46 TC 161 Z9 166 U1 0 U2 22 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 SEP PY 1999 VL 12 IS 9 BP 2719 EP 2733 DI 10.1175/1520-0442(1999)012<2719:MVIGSS>2.0.CO;2 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 237TP UT WOS:000082672400001 ER PT J AU Mestas-Nunez, AM Enfield, DB AF Mestas-Nunez, AM Enfield, DB TI Rotated global modes of non-ENSO sea surface temperature variability SO JOURNAL OF CLIMATE LA English DT Article ID DECADAL CLIMATE VARIABILITY; NORTH PACIFIC; INTERDECADAL VARIABILITY; OCEAN; ATLANTIC; OSCILLATION; RAINFALL; TRENDS AB A varimax rotation was applied to the EOF modes of global SST derived by Enfield and Mestas-Nunez. The SST anomaly record is more than a century long, with a global complex EOF representation of ENSO and a linear trend removed at every grid point. The rotated EOF modes capture localized centers of variability that contribute to the larger-scale spatial patterns of the unrotated modes. The first rotated EOF represents a multidecadal signal with larger. response in the North Atlantic. The second rotated EOF represents an interdecadal fluctuation with larger response in the eastern North Pacific and out of phase fluctuations of smaller amplitude in the central North Pacific. The third rotated EOF captures interdecadal fluctuations in the eastern tropical Pacific with a dominant peak that coincides with the 1982/83ENSO. The fourth rotated EOF has interdecadal to multidecadal nature with larger response in the central equatorial Pacific and quasi-symmetric out-of-phase response in the western North and South Pacific. The fifth mode represents multidecadal fluctuations with large response at about 40 degrees N in the North Pacific. The sixth mode has interannual to interdecadal timescales with largest response confined to the South Atlantic. The authors' rotated modes are dominated by intra- rather than interocean fluctuations supporting the hypothesis that the non-ENSO variability is more regional than global in nature. Analyses of sea level pressure and surface wind stress show that in general the nan-ENSO rotated EOFs are consistent with an ocean response to local atmospheric forcing. An exception is the eastern tropical Pacific mode, which is more consistent with an atmospheric response to changes in the ocean SST. C1 NOAA, Atlantic Oceanog & Meteorol Lab, Miami, FL 33149 USA. Univ Miami, Cooperat Inst Marine & Atmospher Studies, Miami, FL 33152 USA. RP Enfield, DB (reprint author), NOAA, Atlantic Oceanog & Meteorol Lab, 4301 Rickenbacker Causeway, Miami, FL 33149 USA. RI Mestas-Nunez, Alberto/A-1427-2012; Enfield, David/I-2112-2013 OI Mestas-Nunez, Alberto/0000-0002-3546-3668; Enfield, David/0000-0001-8107-5079 NR 29 TC 94 Z9 96 U1 0 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 SEP PY 1999 VL 12 IS 9 BP 2734 EP 2746 DI 10.1175/1520-0442(1999)012<2734:RGMONE>2.0.CO;2 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 237TP UT WOS:000082672400002 ER PT J AU Xu, HHK Eichmiller, FC Giuseppetti, AA Ives, LK Parry, EE Schumacher, GE AF Xu, HHK Eichmiller, FC Giuseppetti, AA Ives, LK Parry, EE Schumacher, GE TI Three-body wear of a hand-consolidated silver alternative to amalgam SO JOURNAL OF DENTAL RESEARCH LA English DT Article DE amalgam alternative; clinical hand consolidation; damage modes; silver; three-body; wear mechanism ID POSTERIOR COMPOSITES; DENTAL AMALGAM; CLINICAL WEAR; HUMAN ENAMEL; CORROSION; CREEP; RESTORATIONS; BREAKDOWN; BEHAVIOR; MERCURY AB Recent studies have investigated a mercury-free silver alternative to amalgam, but the silver powders required a relatively high compaction pressure to consolidate. The aim of the present study was to consolidate a precipitated silver powder into a cohesive solid using an air-driven pneumatic condenser fitted with an amalgam plugger at a clinically realistic load, and to study the mechanisms and rates of three-body wear of the consolidated silver in comparison with that of an amalgam. The silver powder was annealed, rinsed with a dilute acid, and consolidated either in a prepared tooth cavity or in a specimen mold at a load of 15 N. A four-station wear machine was used where each specimen was immersed in a slurry containing polymethyl methacrylate beads, then a steel pin was loaded and rotated against the specimen at a maximum load of 76 N. The flexural strength in MPa (mean +/- SD; n = 10) was 86 +/- 20 for amalgam, 181 +/- 45 for silver with a polished surface, and 202 +/- 21 for silver with a burnished surface. After 4 x 10(5) wear cycles, the wear scar depth in mu m was 134 +/- 54 for amalgam, 143 +/- 8 for polished silver, and 131 +/- 9 for burnished silver, which were not significantly different (Tukey's multiple comparison test; family confidence coefficient = 0.95). SEM examination revealed cracks and fracture pits in the worn surface of amalgam, in contrast to a smooth surface in silver. Wear and material removal in amalgam occurred by microfracture and dislodgement of cracked segments, while wear in the silver occurred by ductile deformation and flow of materials. To conclude, the consolidated silver possesses a three-body wear resistance similar to that of amalgam, and a higher resistance to wear-induced damage and cracking than amalgam. The mechanism of wear in amalgam is microfracture and material dislodgement, while that in consolidated silver is ductile deformation and flow of material. C1 Amer Dent Assoc Hlth Fdn, Paffenbarger Res Ctr, Chicago, IL 60611 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Xu, HHK (reprint author), Amer Dent Assoc Hlth Fdn, Paffenbarger Res Ctr, Bldg 224,Room A-153, Chicago, IL 60611 USA. FU NIDCR NIH HHS [P 50 DE09322] NR 48 TC 7 Z9 7 U1 0 U2 0 PU AMER ASSOC DENTAL RESEARCH PI ALEXANDRIA PA 1619 DUKE ST, ALEXANDRIA, VA 22314 USA SN 0022-0345 J9 J DENT RES JI J. Dent. Res. PD SEP PY 1999 VL 78 IS 9 BP 1560 EP 1567 PG 8 WC Dentistry, Oral Surgery & Medicine SC Dentistry, Oral Surgery & Medicine GA 232CM UT WOS:000082348200011 PM 10512391 ER PT J AU Antonopoulou, E Mayer, I Borg, B Swanson, P Murza, I Christoforov, O AF Antonopoulou, E Mayer, I Borg, B Swanson, P Murza, I Christoforov, O TI Effects of testosterone on gonadotropins, testes, and plasma 17 alpha,2 beta-dihydroxy-4-pregnene-3-one levels in postbreeding mature Atlantic salmon, Salmo salar, male parr SO JOURNAL OF EXPERIMENTAL ZOOLOGY LA English DT Article ID MALE RAINBOW-TROUT; 5 ANDROGENS; GTH-II; REPRODUCTIVE-CYCLE; BALTIC SALMON; COHO SALMON; IN-VITRO; GAIRDNERI; PITUITARY; IMMATURE AB Atlantic salmon, Salmo salar, mature male parr were implanted with testosterone (T) in small (T3) or large (T10) Silastic capsules in the breeding season or at its end in November or December, in order to find out whether the postbreeding decline in 17 alpha,20 beta-dihydroxy-4-pregnene-3-one (17,20 beta-P) and milt production is a consequence of declining T levels. In the first of three experiments, fish were sampled the following January and March, whereas in the second and in the third they were sampled in April. Pituitary and plasma concentrations of gonadotropic hormone (GTHs) I and II and plasma levels of T, 11-ketotestosterone (11-KT) and 17,20 beta-P were measured by radioimmunoassays, and the testes were examined histologically. Administration of T prolonged the period in which running milt was present, suppressed Sertoli cells, and prevented the postbreeding decline in testes weight in experiment two. The postbreeding decline in plasma 17,20 beta-P levels was diminished by T10 in experiment one, and by both T3 and T10 in experiment two. The similar decline in 11-KT levels was not influenced by T treatment (only studied in experiment one). T treatment also prevented a decline in pituitary GTH II content tin experiments two and three) and in plasma GTH II levels (only studied in experiment three). However, pituitary GTH I content was not influenced (experiment two and three), whereas plasma GTH I levels (only studied in experiment three) were suppressed by T To summarize, T treatment prevents postbreeding decline in 17,20 beta-P levels, probably via a stimulation of GTH II secretion. J. Exp. Zool. 284:425-436, 1999. (C) 1999 Wiley-Liss, Inc. C1 Stockholm Univ, Dept Zool, S-10691 Stockholm, Sweden. NOAA, Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, Seattle, WA 98112 USA. St Petersburg State Univ, Dept Evolutionary Physiol, St Petersburg 199034, Russia. RP Antonopoulou, E (reprint author), Univ Rennes 1, Equipe Endocrinol Mol Reprod, CNRS, UPRES A 6026, Campus Beaulieu, F-35042 Rennes, France. RI Antonopoulou, Efthimia/N-4233-2015; OI Antonopoulou, Efthimia/0000-0003-4565-6962 NR 24 TC 15 Z9 15 U1 0 U2 0 PU WILEY-LISS PI NEW YORK PA DIV JOHN WILEY & SONS INC, 605 THIRD AVE, NEW YORK, NY 10158-0012 USA SN 0022-104X J9 J EXP ZOOL JI J. Exp. Zool. PD SEP 1 PY 1999 VL 284 IS 4 BP 425 EP 436 DI 10.1002/(SICI)1097-010X(19990901)284:4<425::AID-JEZ9>3.3.CO;2-Z PG 12 WC Zoology SC Zoology GA 229KZ UT WOS:000082194900009 PM 10451420 ER PT J AU Duewer, DL Liu, HK Reeder, DJ AF Duewer, DL Liu, HK Reeder, DJ TI Graphical tools for RFLP measurement quality assurance: Single-locus charts SO JOURNAL OF FORENSIC SCIENCES LA English DT Article DE forensic science; DNA typing; data analysis; graphical analysis; interlaboratory comparison; statistical intervals; restriction fragment length polymorphism; quality assurance ID DNA PROFILING MEASUREMENTS; FRAGMENT-LENGTH AB Forensic restriction fragment length polymorphism analyses typically provide two results for each sample, one result for each unique allele, at each genetic locus probed. In collaboration with the member laboratories of the Technical Working Group for DNA Analysis Methods, we have developed graphical techniques that compactly summarize even large numbers of such paired measurements. This paper provides a derailed description of the basic tool, a modified bivariate control chart for data from one sample at one locus. We demonstrate how various modifications and combinations of these "single-locus charts" can be used for within- and among-laboratory quality assurance activities. C1 NIST, Div Biotechnol, Chem Sci & Technol Lab, Gaithersburg, MD 20899 USA. NIST, Stat Engn Div, Informat Technol Lab, Gaithersburg, MD 20899 USA. NIST, Div Analyt Chem, Chem Sci & Technol Lab, Gaithersburg, MD 20899 USA. RP Reeder, DJ (reprint author), NIST, Div Biotechnol, Chem Sci & Technol Lab, 100 Bur Dr,STOP 8311, Gaithersburg, MD 20899 USA. RI Duewer, David/B-7410-2008 NR 18 TC 5 Z9 5 U1 0 U2 0 PU AMER SOC TESTING MATERIALS PI W CONSHOHOCKEN PA 100 BARR HARBOR DR, W CONSHOHOCKEN, PA 19428-2959 USA SN 0022-1198 J9 J FORENSIC SCI JI J. Forensic Sci. PD SEP PY 1999 VL 44 IS 5 BP 969 EP 977 PG 9 WC Medicine, Legal SC Legal Medicine GA 293AZ UT WOS:000085830500015 ER PT J AU Gary, KT Duewer, DL Reeder, DJ AF Gary, KT Duewer, DL Reeder, DJ TI Graphical tools for RFLP measurement quality assurance: Laboratory performance charts SO JOURNAL OF FORENSIC SCIENCES LA English DT Article DE forensic science; DNA profiling; graphical analysis; interlaboratory comparison; proficiency testing; quality control; TWGDAM ID DNA PROFILING MEASUREMENTS AB Forensic restriction fragment length polymorphism analyses typically provide two band size results at each genetic locus for each sample. In collaboration with the member laboratories of the Technical Working Group for DNA Analysis Methods, we have developed graphical techniques that compactly summarize even large numbers of such paired measurements. This paper provides a detailed description of the basic tool, a modified bivariate control chart for data from multiple samples and/or multiple loci. We demonstrate how various modifications and combinations of these "laboratory performance charts" can be used for quality control, quality assurance, and quality demonstration. C1 NIST, Div Biotechnol, Chem Sci & Technol Lab, Gaithersburg, MD 20899 USA. NIST, Div Analyt Chem, Chem Sci & Technol Lab, Gaithersburg, MD 20899 USA. RP Reeder, DJ (reprint author), NIST, Div Biotechnol, Chem Sci & Technol Lab, 100 Bur Dr,STOP 8311, Gaithersburg, MD 20899 USA. RI Duewer, David/B-7410-2008 NR 9 TC 2 Z9 3 U1 0 U2 0 PU AMER SOC TESTING MATERIALS PI W CONSHOHOCKEN PA 100 BARR HARBOR DR, W CONSHOHOCKEN, PA 19428-2959 USA SN 0022-1198 J9 J FORENSIC SCI JI J. Forensic Sci. PD SEP PY 1999 VL 44 IS 5 BP 978 EP 982 PG 5 WC Medicine, Legal SC Legal Medicine GA 293AZ UT WOS:000085830500016 PM 10486949 ER PT J AU Ardren, WR Borer, S Thrower, F Joyce, JE Kapuscinski, AR AF Ardren, WR Borer, S Thrower, F Joyce, JE Kapuscinski, AR TI Inheritance of 12 microsatellite loci in Oncorhynchus mykiss SO JOURNAL OF HEREDITY LA English DT Article ID RAINBOW-TROUT POPULATIONS; SALMON SALMO-SALAR; GENETIC-VARIATION; ALLELE FREQUENCY; LINKAGE MAP; NULL ALLELE; DNA MARKERS; MOLECULAR-BASIS; BROWN TROUT; ATLANTIC AB Four full-sib families of Oncorhynchus mykiss were used to study the inheritance of allelic variation at 12 microsatellite loci. The loci examined were previously characterized in six different species from the family Salmonidae, Of the 48 genotypic ratios observed (12 loci x 4 crosses), disomic segregation of codominant autosomal alleles was established in 24 of 31 informative tests, The seven tests that did not conform to Mendelian ratios can be explained by the presence of null alleles (One mu 14 and Omy77) and a locus (One mu 1) that may be tandemly duplicated. Three significant pairwise linkage associations were observed between One mu 1 and Omy207, Ssa85 and One mu 11, and the two loci amplified by One mu 1 primers, indicating these loci are not asserting independently. The presence of unexpected heteroduplex structures in One mu 11 electropherograms in one cross prompted the sequencing of similar microsatellite electromorphs. Sequence differences revealed size homoplasy, that is, the electromorphs were identical in state but they were not identical by descent. These results demonstrate the need to conduct comprehensive species-specific inheritance studies for microsatellite loci used in population genetic or kinship analyses. Discovery of these four attributes by examining a small number of loci in four families suggests that they are common across microsatellite loci overall. C1 Univ Minnesota, Dept Fisheries & Wildlife, AquaGen Lab, St Paul, MN 55108 USA. Natl Marine Fisheries Serv, Auke Bay Lab, Juneau, AK USA. RP Ardren, WR (reprint author), Luther Coll, Dept Biol, 700 Coll Dr, Decorah, IA 52101 USA. NR 58 TC 34 Z9 53 U1 0 U2 1 PU OXFORD UNIV PRESS INC PI CARY PA JOURNALS DEPT, 2001 EVANS RD, CARY, NC 27513 USA SN 0022-1503 J9 J HERED JI J. Hered. PD SEP-OCT PY 1999 VL 90 IS 5 BP 529 EP 536 DI 10.1093/jhered/90.5.529 PG 8 WC Evolutionary Biology; Genetics & Heredity SC Evolutionary Biology; Genetics & Heredity GA 248AX UT WOS:000083254100004 ER PT J AU Dennis, T Young, JF AF Dennis, T Young, JF TI Measurements of BER performance for bipolar encoding of an SFS SO JOURNAL OF LIGHTWAVE TECHNOLOGY LA English DT Article DE code division multiple access (CDMA); optical networks; thermal noise ID ALL-OPTICAL CDMA; WDM APPLICATIONS; SYSTEMS; NOISE; COMMUNICATION; NETWORKS; LIGHT; CODES AB This paper reports on the measurements of bit error rate (BER) performance for a broad-band optical communications scheme that encodes the power spectrum of an erbium-doped superfluourescent fiber source with bipolar equivalent codes. The proposed scheme, like spectrum-sliced wavelength division multiplexing (WDM), suffers from the excess noise associated with the detection of a thermal-like source. BER calculations based on measured testbed characteristics and a simple model are compared with BER measurements for one and two active users. In addition, the performance of a single user in the presence of broad-band spectral interference is investigated, giving a preliminary estimate of multiuser capacity. This paper discusses various solutions for increasing network capacity and performance, relevant to the proposed scheme as well as to wavelength division multiplexing (WDM). C1 Natl Inst Stand & Technol, Boulder, CO 80303 USA. Rice Univ, Dept Elect & Comp Engn, Houston, TX 77251 USA. RP Dennis, T (reprint author), Natl Inst Stand & Technol, 325 Broadway, Boulder, CO 80303 USA. NR 19 TC 10 Z9 10 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0733-8724 J9 J LIGHTWAVE TECHNOL JI J. Lightwave Technol. PD SEP PY 1999 VL 17 IS 9 BP 1542 EP 1546 DI 10.1109/50.788559 PG 5 WC Engineering, Electrical & Electronic; Optics; Telecommunications SC Engineering; Optics; Telecommunications GA 233WM UT WOS:000082450200003 ER PT J AU Reed, RK Mordy, CW AF Reed, RK Mordy, CW TI Bering Sea deep circulation: Water properties and geopotential SO JOURNAL OF MARINE RESEARCH LA English DT Article ID SUBARCTIC PACIFIC-OCEAN; GEOSTROPHIC CIRCULATION; BASIN; CURRENTS AB Deep temperature and silicate data from the Bering Sea demonstrate patterns that are consistent and allow inference of near-bottom circulation. The cold source water enters Kamchatka Strait and mainly moves toward the southeast through a narrow topographic gap and into Bowers Basin. There is also a narrow, coherent flow eastward, and eventually southeastward, near the steep flank of Bowers Ridge. At levels similar to 100-300 m above the bottom, there is a suggestion of upward motion near the margins of much of the deep Bering Sea. Near-bottom geopotential gradients, referred to 3000 db, are in agreement with flow inferred from water properties. C1 NOAA, Pacific Marine Environm Lab, Seattle, WA 98115 USA. Univ Washington, Joint Inst Study Atmosphere & Oceans, Seattle, WA 98195 USA. RP Reed, RK (reprint author), NOAA, Pacific Marine Environm Lab, 7600 Sand Point Way NE, Seattle, WA 98115 USA. NR 15 TC 2 Z9 2 U1 0 U2 0 PU KLINE GEOLOGY LABORATORY PI NEW HAVEN PA YALE UNIV, NEW HAVEN, CT 06520-8109 USA SN 0022-2402 J9 J MAR RES JI J. Mar. Res. PD SEP PY 1999 VL 57 IS 5 BP 763 EP 773 DI 10.1357/002224099321560564 PG 11 WC Oceanography SC Oceanography GA 273LX UT WOS:000084710100003 ER PT J AU Balzaretti, NM Feldman, A Etz, ES Gat, R AF Balzaretti, NM Feldman, A Etz, ES Gat, R TI Growth-rate dependence of the thermal conductivity of chemical-vapor-deposited diamond SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID FILMS; STATE; CVD AB The in-plane thermal diffusivity of chemical-vapor-deposited diamond films was measured as a function of diamond-growth rate. The films, 0.1-0.4 mm thick, were prepared in microwave-plasma reactor at growth rates ranging from 1 to 10 mu m/h. A modification of Angstrom's method was used to perform the diffusivity measurements. The thermal conductivity calculated from the thermal diffusivity shows an inverse relationship with growth rate. Analyses of Raman spectra indicate that both the line shifts and the line widths of the diamond Raman peak are practically independent of the deposition rate, except for the specimen grown at the highest growth rate. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Coatings Technol Solut Inc, Somerville, MA 02143 USA. Univ Fed Rio Grande Sul, Inst Fis, Porto Alegre, RS, Brazil. RP Balzaretti, NM (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RI Balzaretti, Naira/L-3417-2014 OI Balzaretti, Naira/0000-0003-2797-8618 NR 12 TC 3 Z9 3 U1 0 U2 2 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 SEP PY 1999 VL 14 IS 9 BP 3720 EP 3724 DI 10.1557/JMR.1999.0502 PG 5 WC Materials Science, Multidisciplinary SC Materials Science GA 304RX UT WOS:000086498900033 ER PT J AU Chai, H Lawn, B AF Chai, H Lawn, B TI Fracture modes in brittle coatings with large interlayer modulus mismatch SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID FINITE-ELEMENT ANALYSIS; SILICON-NITRIDE BILAYERS; CONTACT DAMAGE; CERAMIC COATINGS; MECHANICAL CHARACTERIZATION; INDENTATION; SUBSTRATE; DEFORMATION; SPHERE AB Fracture modes in a model glass-polymer coating-substrate system indented with hard spheres are investigated. The large modulus mismatch between the glass and polymer results in distinctive transverse fracture modes within the brittle coating: exaggerated circumferential (C) ring cracks that initiate at the upper coating surface well outside the contact (as opposed to the near-contact Hertzian cone fractures observed in monolithic brittle materials); median-radial (M) cracks that initiate at the lower surface (i.e., at the substrate interface) on median planes containing the contact axis. Bonding between the coating and substrate is sufficiently strong as to preclude delamination in our system. The transparency of the constituent materials usefully enables in situ identification and quantification of the two transverse fracture modes during contact. The morphologies of the cracks and the corresponding critical indentation loads for initiation are measured over a broad range of coating thicknesses (20 mu m to 5.6 mm), on coatings with like surface flaw states, here ensured by a prebonding abrasion treatment. There is a well-defined, broad intermediate range where the indented coating responds more like a flexing plate than a Hertzian contact, and where the M and C cracks initiate in close correspondence with a simple critical stress criterion, i.e., when the maximum tensile stresses exceed the bulk strength of the (abraded) glass. In this intermediate range the M cracks generally form first-only when the flaws on the lower surface are removed (by etching) do the C cracks form first. Finite element modeling is used to evaluate the critical stresses at crack initiation and the surface locations of the crack origins. Departures from the critical stress condition occur at the extremes of very thick coatings (monolith limit) and very thin coatings (thin-film limit), where stress gradients over the flaw dimension are large. Implications of the results concerning practical coating systems are considered. C1 Tel Aviv Univ, Fac Engn, Dept Solid Mech Mat & Struct, IL-69978 Tel Aviv, Israel. Natl Inst Stand & Technol, Mat Sci & Engn Lab, Gaithersburg, MD 20899 USA. Natl Met & Mat Technol Ctr, Bangkok 10400, Thailand. RP Tel Aviv Univ, Fac Engn, Dept Solid Mech Mat & Struct, IL-69978 Tel Aviv, Israel. NR 38 TC 135 Z9 138 U1 4 U2 33 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 32 AVENUE OF THE AMERICAS, NEW YORK, NY 10013-2473 USA SN 0884-2914 EI 2044-5326 J9 J MATER RES JI J. Mater. Res. PD SEP PY 1999 VL 14 IS 9 BP 3805 EP 3817 PG 13 WC Materials Science, Multidisciplinary SC Materials Science GA 304RX UT WOS:000086498900045 ER PT J AU Primera, JR Sanchez, M Romero, M Sierraalta, A Ruette, F AF Primera, JR Sanchez, M Romero, M Sierraalta, A Ruette, F TI Analysis of parametric functionals in semiempirical approaches using simulation techniques SO JOURNAL OF MOLECULAR STRUCTURE-THEOCHEM LA English DT Article DE simulation techniques; parametric Hamiltonian; semiempirical methods; model Hamiltonian; parametrization ID SCF-MO METHOD; TRANSITION-METAL COMPLEXES; EFFECTIVE HAMILTONIAN METHOD; DIFFERENTIAL-OVERLAP; QUANTUM-CHEMISTRY; OPTICAL-SPECTRA; GROUND-STATES; ABINITIO; MODEL; MNDO AB In this work a comparative study of energy functional components of a parametric Hamiltonian (H-pa) and those obtained from an analytical method is presented. Error cancellations in approximations occur between electronic and nuclear repulsion energies and between attractive and repulsive electronic components of the energy. Parametric functionals associated with the correlation energy are discussed. Some modifications to the studied H-pa, mainly in the way of simulating electron repulsion integrals, are tested. Simulation techniques based on binding energy functionals were utilized to parameterize the modified H-pa. Preliminary results indicate that important improvements of the total, electronic, and core-core repulsion energies with respect to analytical values can be obtained by modifying the way the electron repulsion integrals in H-pa are simulated. (C) 1999 Elsevier Science B.V. All rights reserved. C1 LUZ, Dept Fis, Maracaibo, Venezuela. IVIC, Ctr Quim, Lab Quim Computac, Caracas, Venezuela. IUT, Dept Quim, Caracas, Venezuela. LUZ, Dept Matemat, Maracaibo, Venezuela. RP Ruette, F (reprint author), Natl Inst Stand & Technol, Phys & Chem Properties Div, Room A11,Bldg 211, Gaithersburg, MD 20899 USA. NR 73 TC 18 Z9 18 U1 0 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0166-1280 J9 J MOL STRUC-THEOCHEM JI Theochem-J. Mol. Struct. PD SEP 1 PY 1999 VL 469 BP 177 EP 190 DI 10.1016/S0166-1280(98)00587-9 PG 14 WC Chemistry, Physical SC Chemistry GA 230VZ UT WOS:000082273500019 ER PT J AU Prosser, WH Hamstad, MA Gary, J O'Gallagher, A AF Prosser, WH Hamstad, MA Gary, J O'Gallagher, A TI Finite element and plate theory modeling of acoustic emission waveforms SO JOURNAL OF NONDESTRUCTIVE EVALUATION LA English DT Article DE acoustic emission; plate theory; finite element modeling ID MATRIX CRACKING; WAVES AB A comparison was made between two approaches to predict acoustic emission waveforms in thin plates. A normal mode solution method for Mindlin plate theory was used to predict the response of the flexural plate mode to a point source, step-function load, applied on the plate surface. The second approach used a dynamic finite element method to model the problem using equations of motion based on exact linear elasticity. Calculations were made using properties for both isotropic (aluminum) and anisotropic (unidirectional graphite/epoxy composite) materials. For simulations of anisotropic plates, propagation along multiple directions was evaluated. in general, agreement between the two theoretical approaches was good. Discrepancies in the waveforms at longer times were caused by differences in reflections from the lateral plate boundaries. These differences resulted from the fact that the two methods used different boundary conditions. At shorter times in the signals, before reflections, the slight discrepancies in the waveforms were attributed to limitations of Mindlin plate theory, which is an approximate plate theory. The advantages of the finite element method are that it used the exact linear elasticity solutions, and that it can be used to model real source conditions and complicated, finite specimen geometries as well as thick plates. These advantages come at a cost of increased computational difficulty, requiring lengthy calculations on workstations or supercomputers. The Mindlin plate theory solutions, meanwhile, can be quickly generated on personal computers. Specimens with finite geometry can also be modeled. However, only limited simple geometries such as circular or rectangular plates can easily be accommodated with the normal mode solution technique. Likewise, very Limited source configurations can be modeled and plate theory is applicable only to thin plates. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. Univ Denver, Denver, CO 80208 USA. Natl Inst Stand & Technol, Boulder, CO 80303 USA. RP NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 20 TC 33 Z9 33 U1 1 U2 11 PU SPRINGER/PLENUM PUBLISHERS PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0195-9298 EI 1573-4862 J9 J NONDESTRUCT EVAL JI J. Nondestruct. Eval. PD SEP PY 1999 VL 18 IS 3 BP 83 EP 90 DI 10.1023/A:1021888009896 PG 8 WC Materials Science, Characterization & Testing SC Materials Science GA 270AQ UT WOS:000084513600001 ER PT J AU Clark, AV Hehman, CS Gallagher, D Lozev, MG Fuchs, PA AF Clark, AV Hehman, CS Gallagher, D Lozev, MG Fuchs, PA TI Ultrasonic measurement of stress in pin and hanger connections SO JOURNAL OF NONDESTRUCTIVE EVALUATION LA English DT Article DE acoustoelasticity; stress; EMATs; bridges AB Pin and hanger connections are used in bridges to suspend an interior span from the outer spans. The connections can sometimes lock up due to corrosion. If lockup occurs the stresses in the connection are cycled due to thermal expansion and contraction of the bridge; fatigue cracking and failure may occur. We constructed an apparatus to simulate a locked-up pin and hanger connection. We performed proof-of-concept tests of a method to detect stresses in pin and hanger connections. The method uses the stress-induced changes in sound velocity of shear waves polarized parallel and perpendicular to the hanger axis. The birefringence is the normalized difference in these shear wave velocities. We measured the birefringence at opposite sides of the hangers, at midsection. We simulated three scenarios: continuous monitoring of hanger status; intermittent monitoring from a known initial state; measurement with no a priori knowledge of hanger status. Good agreement with strain gauge data was obtained for all three scenarios. C1 Natl Inst Stand & Technol, Boulder, CO 80303 USA. Virginia Transportat Res Council, Charlottesville, VA 22903 USA. Fed Highway Adm, Mclean, VA 22101 USA. RP Clark, AV (reprint author), Stress Sensors Inc, 2785 Heather Rd, Golden, CO 80401 USA. NR 16 TC 1 Z9 1 U1 1 U2 3 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0195-9298 J9 J NONDESTRUCT EVAL JI J. Nondestruct. Eval. PD SEP PY 1999 VL 18 IS 3 BP 103 EP 113 DI 10.1023/A:1021860727643 PG 11 WC Materials Science, Characterization & Testing SC Materials Science GA 270AQ UT WOS:000084513600004 ER PT J AU Zimmerman, BE Cessna, JT Unterweger, MP Li, AN Whiting, JS Knapp, FFR AF Zimmerman, BE Cessna, JT Unterweger, MP Li, AN Whiting, JS Knapp, FFR TI A new experimental determination of the dose calibrator setting for Re-188 SO JOURNAL OF NUCLEAR MEDICINE LA English DT Article DE dose calibrators; Re-188 ID HALF-LIFE AB Accurate activity measurements of radionuclides using commercial dose calibrators requires that the correct dial setting (or calibration factor) be applied. The dose calibrator setting for the medical radionuclide Re-188 (as (ReO4-)-Re-188) has been determined experimentally using solution sources prepared and calibrated at the National Institute of Standards and Technology (NIST). Methods: The specific activity of two sources (in units of MBq/g) in the standard 5-mL NIST ampoule and in a 5-mL SoloPak dose vial were calibrated using 4 pi beta liquid scintillation counting with H-3-standard efficiency tracing and gamma-ray/bremmstrahlung counting in the NIST "4 pi" gamma ionization chamber on gravimetrically related sources. Results: The newly determined settings for the NIST Capintec CRC-12 dose calibrator are (631 +/- 4) x 10 and (621 +/- 3) x 10 for the respective ampoule and dose vial geometries with an expanded (at a presumed 95% confidence level) uncertainty of 0.4%-0.5% in the activity determination. The setting for the dose vial geometry was independently confirmed using a Capintec CRC-15R at Cedars-Sinai Medical Center using sources calibrated against a NIST standard. Conclusion: These new settings result in activity readings 28%-30% lower than those obtained using the previously recommended setting of 496 x 10. This discrepancy most likely results from underestimating the total radiation yield from Re-188 decay when calculating the dose calibrator response. This study emphasizes the need for experimental determinations of dose calibrator settings in the geometry in which the measurements will be performed. C1 Natl Inst Stand & Technol, Phys Lab, Gaithersburg, MD 20899 USA. Cedars Sinai Med Ctr, Dept Med Phys & Imaging, Los Angeles, CA 90048 USA. Oak Ridge Natl Lab, Div Life Sci, Oak Ridge, TN USA. RP Zimmerman, BE (reprint author), Natl Inst Stand & Technol, Phys Lab, Bldg 245,Rm C114, Gaithersburg, MD 20899 USA. NR 23 TC 14 Z9 15 U1 0 U2 0 PU SOC NUCLEAR MEDICINE INC PI RESTON PA 1850 SAMUEL MORSE DR, RESTON, VA 20190-5316 USA SN 0161-5505 J9 J NUCL MED JI J. Nucl. Med. PD SEP PY 1999 VL 40 IS 9 BP 1508 EP 1516 PG 9 WC Radiology, Nuclear Medicine & Medical Imaging SC Radiology, Nuclear Medicine & Medical Imaging GA 234ZU UT WOS:000082514900020 PM 10492373 ER PT J AU Herron, JT AF Herron, JT TI Evaluated chemical kinetics data for reactions of N(D-2), N(P-2), and N2(A(3)Sigma(+)(u)) in the gas phase SO JOURNAL OF PHYSICAL AND CHEMICAL REFERENCE DATA LA English DT Article DE air pollution; chemical kinetics; data evaluation; excited states; gas phase; nitrogen; plasma; rate coefficient ID ENERGY-TRANSFER REACTIONS; METASTABLE NITROGEN-ATOMS; RATE CONSTANTS; VIBRATIONAL-RELAXATION; COLLISIONAL DEACTIVATION; BRANCHING RATIOS; N(2 D-2); EXCITATION; MOLECULES; O-2 AB Chemical kinetics data for the gas phase reactions of the first two electronically excited states of atomic nitrogen: N(D-2) and N(P-2), and of the first excited state of molecular nitrogen N-2(A (3)Sigma(u)(+)) are compiled and evaluated. The experimental data for 127 reactions are summarized, the experimental method and year of publication given, a recommended value given for the rate constant for each reaction at 298 K, and where possible, its temperature dependence. The reaction mechanisms are discussed within the limits of the available quantitative product yield data. The literature has been covered through early 1999,There are 94 references. (C) 1999 American Institute of Physics and American Chemical Society. [S0047-2689(99)00105-1]. C1 Natl Inst Stand & Technol, Chem Sci & Technol Lab, Gaithersburg, MD 20899 USA. RP Herron, JT (reprint author), Natl Inst Stand & Technol, Chem Sci & Technol Lab, Gaithersburg, MD 20899 USA. NR 93 TC 282 Z9 285 U1 2 U2 32 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0047-2689 J9 J PHYS CHEM REF DATA JI J. Phys. Chem. Ref. Data PD SEP-OCT PY 1999 VL 28 IS 5 BP 1453 EP 1483 DI 10.1063/1.556043 PG 31 WC Chemistry, Multidisciplinary; Chemistry, Physical; Physics, Multidisciplinary SC Chemistry; Physics GA 289TV UT WOS:000085638800002 ER PT J AU Archer, DG AF Archer, DG TI Thermodynamic properties of import to environmental processes and remediation. II. Previous thermodynamic property values for nickel and some of its compounds SO JOURNAL OF PHYSICAL AND CHEMICAL REFERENCE DATA LA English DT Review DE enthalpy of formation; entropy; Gibbs energy of formation; nickel; nickel compounds; thermodynamic properties ID GIBBS FREE-ENERGY; AQUEOUS-SOLUTIONS; ACTIVITY-COEFFICIENTS; SOLUBILITY PRODUCT; STANDARD ENTHALPY; HIGH-TEMPERATURES; EMF-MEASUREMENTS; ION FORMATION; NI2+ ION; NIO AB The sources of previous thermodynamic property values are detailed for nickel and some compounds of nickel that might be expected as derived from anthropogenic introduction of nickel into the environment or are required for calculation of thermodynamic properties of nickel-containing systems. Included are descriptions of the sources of information and the methodology used to obtain the values for these compounds reported in the NBS series of publications loosely and collectively referred to as the NBS Thermodynamics Tables. (C) 2000 American Institute of Physics and American Chemical Society. [S0047-2689(99)00306-2]. C1 Natl Inst Stand & Technol, Phys & Chem Properties Div, Gaithersburg, MD 20899 USA. RP Archer, DG (reprint author), Natl Inst Stand & Technol, Phys & Chem Properties Div, Gaithersburg, MD 20899 USA. NR 165 TC 6 Z9 6 U1 1 U2 6 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0047-2689 J9 J PHYS CHEM REF DATA JI J. Phys. Chem. Ref. Data PD SEP-OCT PY 1999 VL 28 IS 5 BP 1485 EP 1507 DI 10.1063/1.556044 PG 23 WC Chemistry, Multidisciplinary; Chemistry, Physical; Physics, Multidisciplinary SC Chemistry; Physics GA 289TV UT WOS:000085638800003 ER PT J AU Yu, XR McPhaden, MJ AF Yu, XR McPhaden, MJ TI Dynamical analysis of seasonal and interannual variability in the equatorial Pacific SO JOURNAL OF PHYSICAL OCEANOGRAPHY LA English DT Article ID SEA-SURFACE TEMPERATURE; ZONAL PRESSURE-GRADIENT; ATMOSPHERE OCEAN MODEL; FAST-WAVE LIMIT; TROPICAL PACIFIC; EL-NINO; MOMENTUM BALANCE; ROSSBY-WAVE; CYCLE; ATLANTIC AB Time series measurements from the Tropical Atmosphere Ocean array during the 1980s and 1990s are used to analyze the dynamics of the long-term mean, the seasonal cycle, and interannual variability in the upper 250 m of the equatorial Pacific. The analysis is based on a diagnosis of the zonal momentum equation using surface winds, ocean temperatures, and currents between 165 degrees E and 110 degrees W along the equator. In the mean, the balance is mainly between zonal wind stress and depth-integrated zonal pressure gradient, in good agreement with linear Sverdrup theory. For the seasonal cycle, the balance is mainly between wind stress, pressure gradient, and local acceleration. with differences between the stress and pressure gradient leading to accelerations and decelerations of the South Equatorial Current and Equatorial Undercurrent. On interannual timescales, local acceleration is much smaller than either zonal wind stress or zonal pressure gradient, indicating that to zeroth order, variations in the equatorial Pacific are in quasi-equilibrium with the wind forcing. Consistent with this quasi-equilibrium balance, Equatorial Undercurrent transports in the thermocline vary nearly in phase with the strength of the zonal pressure gradient and the easterly trade winds. Nonlinear effects are significant on all timescales, though of secondary importance in the depth-integrated zonal momentum balance. C1 Univ Washington, Sch Oceanog, Seattle, WA 98195 USA. NOAA, Pacific Marine Environm Lab, Seattle, WA 98115 USA. RP Yu, XR (reprint author), UCSB OPL, 6487 Calle Real,Unit A, Goleta, CA 93117 USA. RI McPhaden, Michael/D-9799-2016 NR 82 TC 25 Z9 25 U1 0 U2 2 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 SEP PY 1999 VL 29 IS 9 BP 2350 EP 2369 DI 10.1175/1520-0485(1999)029<2350:DAOSAI>2.0.CO;2 PG 20 WC Oceanography SC Oceanography GA 246EC UT WOS:000083150600015 ER PT J AU Bryan, K Dukowicz, JK Smith, RD AF Bryan, K Dukowicz, JK Smith, RD TI On the mixing coefficient in the parameterization of bolus velocity SO JOURNAL OF PHYSICAL OCEANOGRAPHY LA English DT Article ID GLOBAL OCEAN CIRCULATION; MESOSCALE TRACER TRANSPORTS; HEAT-TRANSPORT; BETA-PLANE; EDDIES; MODELS; ATLANTIC; FLOW AB Mesoscale eddies in the ocean play an important role in the ocean circulation. In order to simulate the ocean circulation, mesoscale eddies must be included explicitly or parameterized. The eddy permitting calculations of the Los Alamos ocean circulation model offer a special opportunity to test aspects of parameterizations that have recently been proposed. Although the calculations are for a model in level coordinates, averages over a five-year period have been carried out by interpolating to instantaneous isopycnal surfaces. The magnitude of "thickness mixing" or bolus velocity is found to coincide with areas of intense mesoscale activity in the western boundary currents of the Northern Hemisphere and the Antarctic Circumpolar Current. The model also predicts relatively large bolus fluxes in the equatorial region. The analysis does show that the rotational component of the bolus velocity is significant. Predictions of the magnitude of the bolus velocity, assuming downgradient mixing of thickness with various mixing coefficients, have been compared directly with the model. The coefficient proposed by Held and Larichev provides a rather poor fit to the model results because it predicts large bolus velocity magnitudes at high latitudes and in other areas in which there is only a small amount of mesoscale activity. A much better fit is obtained using a constant mixing coefficient or a mixing coefficient originally proposed by Stone in a somewhat different context. The best fit to the model is obtained with a coefficient proportional to lambda(2)/T, where lambda is the radius of deformation, and T is the Eady timescale for the growth of unstable baroclinic waves. C1 Princeton Univ, Program Atmospher & Ocean Sci, Princeton, NJ 08544 USA. Univ Calif Los Alamos Natl Lab, Div Theoret, Los Alamos, NM USA. RP Bryan, K (reprint author), Princeton Univ, Program Atmospher & Ocean Sci, POB CN710,Sayre Hall, Princeton, NJ 08544 USA. NR 28 TC 54 Z9 54 U1 3 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 SEP PY 1999 VL 29 IS 9 BP 2442 EP 2456 DI 10.1175/1520-0485(1999)029<2442:OTMCIT>2.0.CO;2 PG 15 WC Oceanography SC Oceanography GA 246EC UT WOS:000083150600021 ER PT J AU Napp, JM Mier, K Cohen, MK AF Napp, JM Mier, K Cohen, MK TI Estimation of larval fish prey volume: mensuration formulae for copepod nauplii SO JOURNAL OF PLANKTON RESEARCH LA English DT Article ID POLLOCK THERAGRA-CHALCOGRAMMA; SOUTHEASTERN BERING SEA; EASTERN ENGLISH-CHANNEL; SOUTHERN NORTH-SEA; SHELIKOF STRAIT; FOOD; ALASKA; GULF; BAY AB Prey volume measurements are used to determine feeding bioenergetics and transfer of energy between trophic levels. Quantitative estimation of larval fish feeding success often depends on accurate estimates of prey volume inside the gut. Many marine fish larvae begin their lives feeding on copepod nauplii. Various methods and formulae have been proposed to estimate bodily volume of this diverse and difficult to identify group of organisms. We estimated the mean square error and average error for six different single-measurement formulae used to calculate bodily volume for two stages (NI and NIV) of three different copepod genera found in the eastern Bering Sea (Metridia, Oithona and Pseudocalanus). Each method used an assumed or empirical relationship among the three bodily dimensions (length, width and depth). Methods that assume a single geometric model and fixed bodily proportions for all nauplii are shown to be poor estimators of bodily volume. Mensuration methods must take into account the variety of body forms and changes in proportions during development for accurate estimation of bodily volume. It is possible, however, to reduce the number of measurements needed (i.e. to assume fixed bodily proportions) if one accounts for differences among taxa and developmental stages. C1 NOAA, Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr, Seattle, WA 98115 USA. Univ Washington, Joint Inst Study Atmosphere & Oceans, Seattle, WA 98195 USA. RP Napp, JM (reprint author), NOAA, Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr, 7600 Sand Point Way NE, Seattle, WA 98115 USA. NR 17 TC 1 Z9 1 U1 1 U2 1 PU OXFORD UNIV PRESS PI OXFORD PA GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND SN 0142-7873 J9 J PLANKTON RES JI J. Plankton Res. PD SEP PY 1999 VL 21 IS 9 BP 1633 EP 1642 DI 10.1093/plankt/21.9.1633 PG 10 WC Marine & Freshwater Biology; Oceanography SC Marine & Freshwater Biology; Oceanography GA 238BT UT WOS:000082691600003 ER PT J AU Nechvatal, J Barker, E Dodson, D Dworkin, M Foti, J Roback, E AF Nechvatal, J Barker, E Dodson, D Dworkin, M Foti, J Roback, E TI Status report on the first round of the development of the advanced encryption standard SO JOURNAL OF RESEARCH OF THE NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY LA English DT Article DE Advanced Encryption Standard (AES); cryptography; cryptanalysis; cryptographic algorithms; encryption AB In 1997, the National Institute of Standards and Technology (NIST) initiated a process to select a symmetric-key encryption algorithm to be used to protect sensitive (unclassified) Federal information in furtherance of NIST's statutory responsibilities. In 1998, NIST announced the acceptance of 15 candidate algorithms and requested the assistance of the cryptographic research community in analyzing the candidates. This analysis included an initial examination of the security and efficiency characteristics for each algorithm. NIST has reviewed the results of this research and selected five algorithms (MARS, RC6(TM), Rijndael, Serpent and Twofish) as finalists. The research results and rationale for the selection of the finalists are documented in this report. The five finalists will be the subject of further study before the selection of one or more of these algorithms for inclusion in the Advanced Encryption Standard. C1 Natl Inst Stand & Technol, Informat Technol Lab, Comp Secur Div, Gaithersburg, MD 20899 USA. RP Nechvatal, J (reprint author), Natl Inst Stand & Technol, Informat Technol Lab, Comp Secur Div, Gaithersburg, MD 20899 USA. NR 40 TC 2 Z9 2 U1 0 U2 1 PU US GOVERNMENT PRINTING OFFICE PI WASHINGTON PA SUPERINTENDENT DOCUMENTS,, WASHINGTON, DC 20402-9325 USA SN 1044-677X J9 J RES NATL INST STAN JI J. Res. Natl. Inst. Stand. Technol. PD SEP-OCT PY 1999 VL 104 IS 5 BP 435 EP 459 PG 25 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 264NJ UT WOS:000084188100001 ER PT J AU Ferraris, CF AF Ferraris, CF TI Measurement of the rheological properties of high performance concrete; State of the art report SO JOURNAL OF RESEARCH OF THE NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY LA English DT Article DE building technology; concrete; flow properties; mortar; rheology; rheological measurements; rheological; models; test methods; suspension; workability AB The rheological or flow properties of concrete in general and of high performance concrete (HPC) in particular, are important because many factors such as ease of placement, consolidation, durability, and strength depend on the flow properties. Concrete that is not properly consolidated may have defects, such as honeycombs, air voids, and aggregate segregation. Such an important performance attribute has triggered the design of numerous test methods. Generally, the flow behavior of concrete approximates that of a Bingham fluid. Therefore, at least two parameters, yield stress and viscosity, are necessary to characterize the flow. Nevertheless, most methods measure only one parameter. Predictions of the flow properties of concrete from its composition or from the properties of its components are not easy. No general model exists, although some attempts have been made. This paper gives an overview of the flow properties of a fluid or a suspension, followed by a critical review of the most commonly used concrete rheology tests, particular attention is given to tests that could be used for HPC. Tentative definitions of terms such as workability, consistency, and rheological parameters are provided. An overview of the most promising tests and models for cement paste is given. C1 Natl Inst Stand & Technol, Bldg & Fire Res Lab, Bldg Mat Div, Gaithersburg, MD 20899 USA. RP Ferraris, CF (reprint author), Natl Inst Stand & Technol, Bldg & Fire Res Lab, Bldg Mat Div, Gaithersburg, MD 20899 USA. NR 47 TC 92 Z9 98 U1 1 U2 10 PU US GOVERNMENT PRINTING OFFICE PI WASHINGTON PA SUPERINTENDENT DOCUMENTS,, WASHINGTON, DC 20402-9325 USA SN 1044-677X J9 J RES NATL INST STAN JI J. Res. Natl. Inst. Stand. Technol. PD SEP-OCT PY 1999 VL 104 IS 5 BP 461 EP 478 PG 18 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 264NJ UT WOS:000084188100002 ER PT J AU Mielenz, KD AF Mielenz, KD TI On the diffraction limit for lensless imaging SO JOURNAL OF RESEARCH OF THE NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY LA English DT Article DE aperture diameter; diffraction; Fraunhofer-Airy profile; Fresnel-Lommel theory; image size; irradiance; lensless imaging; Petzval; pinhole photography; radiant flux; Rayleigh; resolution; Sparrow criterion AB The diffraction limit for lensless imaging, defined as the sharpest possible point image obtainable with a pinhole aperture, is analyzed and compared to the corresponding limit for imaging with lenses by means of theoretical considerations and numerical computations using the Fresnel-Lommel diffraction theory for circular apertures. The numerical result (u = pi) obtained for the best configuration parameter u which defines the optical setup is consistent with the quarter-wave criterion, and is the same as the value reported in a classical paper by Petzval but smaller than the Value (u =1.8 pi) found by Lord Rayleigh. The smallest discernible detail (pixel) in a composite image is defined by an expression found by Rayleigh on applying the half-wave criterion and is shown to be consistent with the Sparrow criterion of resolution. The numerical values of other measures of image size are reported and compared to equivalent parameters of the Fraunhofer-Airy profile that governs imaging with lenses. C1 NIST, Phys Lab, Radiometr Phys Div, Gaithersburg, MD 20899 USA. RP Mielenz, KD (reprint author), NIST, Phys Lab, Radiometr Phys Div, Gaithersburg, MD 20899 USA. NR 6 TC 9 Z9 9 U1 0 U2 2 PU US GOVERNMENT PRINTING OFFICE PI WASHINGTON PA SUPERINTENDENT DOCUMENTS,, WASHINGTON, DC 20402-9325 USA SN 1044-677X J9 J RES NATL INST STAN JI J. Res. Natl. Inst. Stand. Technol. PD SEP-OCT PY 1999 VL 104 IS 5 BP 479 EP 485 PG 7 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 264NJ UT WOS:000084188100003 ER PT J AU Murthy, AV Tsai, BK Saunders, RD AF Murthy, AV Tsai, BK Saunders, RD TI Comparative calibration of heat flux sensors in two blackbody facilities SO JOURNAL OF RESEARCH OF THE NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY LA English DT Article DE heat flux; irradiance; sensor; transfer calibration AB This paper presents the results of heat flux sensor calibrations in two blackbody facilities: the 25 mm variable temperature blackbody (VTBB) primary facility and a recently developed 51 mm aperture spherical blackbody (SPBB) facility. Three Schmidt-Boelter gages and a Garden gage were calibrated with reference to an electrical substitution radiometer in the VTBB. One of the Schmidt-Boelter gages thus calibrated was used as a reference standard to calibrate other gages in the SPBB. Comparison of the Schmidt-Boelter gages calibrations in the SPBB and the VTBB agreed within the measurement uncertainties. For the Garden gage, the measured responsivity in the SPBB showed a gradual decrease with increasing distance from the aperture. When the gage was located close to the aperture, a distance less than the aperture radius, the responsivity in the SPBB agreed with VTBB measurements. At a distance of about three times the aperture radius, the responsivity showed a decrease of about 4%. This is probably due to higher convection loss from the Garden gage surface compared to the Schmidt-Boelter sensor. C1 Aerotech Inc, Hampton, VA 23666 USA. Natl Inst Stand & Technol, Phys Lab, Opt Technol Div, Gaithersburg, MD 20899 USA. RP Murthy, AV (reprint author), Aerotech Inc, Hampton, VA 23666 USA. NR 6 TC 10 Z9 10 U1 0 U2 2 PU US GOVERNMENT PRINTING OFFICE PI WASHINGTON PA SUPERINTENDENT DOCUMENTS,, WASHINGTON, DC 20402-9325 USA SN 1044-677X J9 J RES NATL INST STAN JI J. Res. Natl. Inst. Stand. Technol. PD SEP-OCT PY 1999 VL 104 IS 5 BP 487 EP 494 PG 8 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 264NJ UT WOS:000084188100004 ER PT J AU Lev, SM McLennan, SM Hanson, GN AF Lev, SM McLennan, SM Hanson, GN TI Mineralogic controls on REE mobility during black-shale diagenesis SO JOURNAL OF SEDIMENTARY RESEARCH LA English DT Article ID RARE-EARTH ELEMENTS; LOW-GRADE METAMORPHISM; MARGINAL BASIN; SEDIMENTARY; REDISTRIBUTION; WALES; OCEANS; USA; ND AB The Llandeilo-Caradoc black shales of southwest Wales, U.K. record a paragenetic sequence that requires redistribution of rare earth elements (REE) on a mineralogic scale during diagenesis. The main evidence for this redistribution is formation and replacement of PEE-rich apatite and monazite and variations in whole-rock REE patterns. The processes that produce these mineralogic changes create a diagenetic overprint on the Llandeilo-Caradoc black shales that obscures geochemical information related to both provenance and paleoenvirommental conditions of deposition. Periods of open-system conditions existed during the diagenetic alteration of the Llandeilo-Caradoc black shales, which allow an evaluation of the extent and timing of the REE redistribution inferred from petrography. The observed variations in La/Sm ratios in the whole-rock REE patterns are strong evidence that REE were redistributed on a scale greater than an individual hand sample. This change in the whole-rock REE pattern altered the Cerium anomaly by as much as 20% and produced a range in the Sm/Nd ratio from 0.14 to 0.20, This change in the whole-rock Sm/Nd ratio indicates a disturbance in the Sm-Nd isotopic system at about 460 Ma that can be directly linked to the formation and dissolution of diagenetic apatite and monazite during diagenesis, One effect of this disturbance is to alter the range in Nd model age for the Llandeilo-Caradoc black shales from 1.6 to 1.8 Ga to about 1.4 to 2.25 Ga, thus complicating any interpretation of provenance. The ability to link petrographic observations from a black shale to measurable whole-rock geochemical changes provides us with one tool to evaluate the presence of a diagenetic overprint on trace elements commonly used in paleoenvironmental reconstruction. C1 SUNY Stony Brook, Dept Geosci, Stony Brook, NY 11794 USA. RP Lev, SM (reprint author), Natl Inst Stand & Technol, 100 Bur Dr,Mail Stop 8391, Gaithersburg, MD 20899 USA. NR 47 TC 40 Z9 40 U1 0 U2 16 PU SEPM-SOC SEDIMENTARY GEOLOGY PI TULSA PA 1731 E 71ST STREET, TULSA, OK 74136-5108 USA SN 1073-130X J9 J SEDIMENT RES JI J. Sediment. Res. PD SEP PY 1999 VL 69 IS 5 BP 1071 EP 1082 PN A PG 12 WC Geology SC Geology GA 237CQ UT WOS:000082638100011 ER PT J AU Simiu, E Filliben, JJ AF Simiu, E Filliben, JJ TI Design gust wind speeds in the United States - Discussion SO JOURNAL OF STRUCTURAL ENGINEERING-ASCE LA English DT Editorial Material C1 Natl Inst Stand & Technol, Informat Technol Lab, Gaithersburg, MD 20899 USA. NR 0 TC 6 Z9 6 U1 0 U2 5 PU ASCE-AMER SOC CIVIL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2398 USA SN 0733-9445 J9 J STRUCT ENG-ASCE JI J. Struct. Eng.-ASCE PD SEP PY 1999 VL 125 IS 9 BP 1077 EP 1078 DI 10.1061/(ASCE)0733-9445(1999)125:9(1077) PG 2 WC Construction & Building Technology; Engineering, Civil SC Construction & Building Technology; Engineering GA 226EK UT WOS:000082007200017 ER PT J AU Parkhurst, WJ Tanner, RL Weatherford, FP Valente, RJ Meagher, JF AF Parkhurst, WJ Tanner, RL Weatherford, FP Valente, RJ Meagher, JF TI Historic PM2.5/PM10 concentrations in the southeastern United States - Potential implications of the revised particulate matter standard SO JOURNAL OF THE AIR & WASTE MANAGEMENT ASSOCIATION LA English DT Article ID GREAT-SMOKY-MOUNTAINS; PM(2.5); AEROSOL; PM(10) AB This report summarizes a PM2.5/PM10 particulate matter data set consisting of 861 PM2.5/PM10 sample pairs collected with dichotomous samplers by the Tennessee Valley Authority (TVA) from 1982 to 1991. Eight monitoring stations, ranging from urban-industrial to rural-background, were operated across three east-central U.S. states. Annual average PM2.5 concentrations ranged from 12.6 to 21.3 micrograms per cubic meter (mu g/m(3)), with an overall mean of 15.7 mu g/m(3). Likewise, annual average PM10 concentrations ranged from 17.8 to 33.7 mu g/m(3), with an overall mean of 23.7 mu g/m(3). High summer-low winter seasonality was evident, particularly for PM2.5, with the highest monthly PM2.5 and PM10 concentrations in August (26.4 and 37.5 mu g/m(3), respectively) and the lowest in February (9.9 and 15.3 mu g/m(3), respectively). A strong association (r(2) = 0.84) was found between PM2.5 and PM10 mass with PM2.5 mass contributing, on average, 67% of PM10 mass. Applying TVA's PM2.5/PM10 ratio to recent (1993-1995) regional high-volume PM10 Aerometric Information Retrieval System (AIRS) data for the east-central United States suggests that as many as 80% of monitored counties would have equaled or exceeded the level of the new annual PM2.5 metric of 15 mu g/m(3). A decline in average PM2.5 mass on the order of 3-5 mu g/m(3) from 1982 through 1991 is also suggested. Daily PM2.5 mass appears to be reasonably well associated (r = 0.47) with maximum hourly ozone during the warmer months (spring through fall). Sulfate compounds comprise a major portion of the measured PM2.5 mass, with that fraction being highest in the summer months. Viewed collectively, these data suggest that although compliance with the annual and 24-hr PM10 and 24-hr PM2.5 metrics should prove readily attainable, the annual PM2.5 metric will present a major regulatory management challenge for much of the east-central United States. C1 Tennessee Valley Author, Environm Res & Serv, Atmospher Sci & Environm Assessments Dept, Muscle Shoals, AL USA. Natl Ocean & Atmospher Adm, Aeron Lab, Hlth Atmosphere Program, Boulder, CO USA. RP Parkhurst, WJ (reprint author), Tennessee Valley Author, Environm Res & Serv, Atmospher Sci & Environm Assessments Dept, Muscle Shoals, AL USA. NR 16 TC 21 Z9 23 U1 0 U2 8 PU AIR & WASTE MANAGEMENT ASSOC PI PITTSBURGH PA ONE GATEWAY CENTER, THIRD FL, PITTSBURGH, PA 15222 USA SN 1047-3289 J9 J AIR WASTE MANAGE JI J. Air Waste Manage. Assoc. PD SEP PY 1999 VL 49 IS 9 BP 1060 EP 1067 PG 8 WC Engineering, Environmental; Environmental Sciences; Meteorology & Atmospheric Sciences SC Engineering; Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA 240NW UT WOS:000082832900005 ER PT J AU Barsoum, MW Farber, L Levin, I Procopio, A El-Raghy, T Berner, A AF Barsoum, MW Farber, L Levin, I Procopio, A El-Raghy, T Berner, A TI High-resolution transmission electron microscopy of Ti4AlN3, or Ti3Al2N2 revisited SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Article ID TITANIUM-ALUMINUM MULTILAYERS; AL-N SYSTEM; FCC TITANIUM; TERNARY NITRIDE; TI; TI3SIC2 AB The structure and chemistry of what initially was proposed to be Ti3Al2N2 are incorrect. Using high-resolution transmission electron microscopy, together with chemical analysis, the stoichiometry of this compound is concluded to be Ti4AlN3-6 (where delta = 0.1). The structure is layered, wherein every four layers of almost-close-packed Ti atoms are separated by a layer-of Al atoms. The N atoms occupy similar to 97.5% of the octahedral sites between the Ti atoms. The unit cell is comprised of eight layers of Ti atoms and two layers of Al atoms; the unit cell is hexagonal with P6(3)/mmc symmetry (lattice parameters of a = 0.3 nm and c = 2.33 nm), This compound-is machinable and closely related to other layered, ternary, machinable, hexagonal nitrides and carbides, namely M(2)AX and M(3)AX(2) (where M is an early transition metal, A is an A-group element, and X is carbon and/or nitrogen). C1 Drexel Univ, Dept Mat Engn, Philadelphia, PA 19104 USA. Natl Inst Stand & Technol, Div Ceram, Gaithersburg, MD 20899 USA. Technion Israel Inst Technol, Haifa, Israel. RP Barsoum, MW (reprint author), Drexel Univ, Dept Mat Engn, Philadelphia, PA 19104 USA. RI Levin, Igor/F-8588-2010 NR 22 TC 71 Z9 72 U1 1 U2 16 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, PO BOX 6136, WESTERVILLE, OH 43081-6136 USA SN 0002-7820 J9 J AM CERAM SOC JI J. Am. Ceram. Soc. PD SEP PY 1999 VL 82 IS 9 BP 2545 EP 2547 PG 3 WC Materials Science, Ceramics SC Materials Science GA 291XA UT WOS:000085763600036 ER PT J AU Wenthold, PG Hu, J Squires, RR Lineberger, WC AF Wenthold, PG Hu, J Squires, RR Lineberger, WC TI Photoelectron spectroscopy of the trimethylenemethane negative ion SO JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY LA English DT Article ID LOW-LYING TRIPLET; TRANSITION-STATE SPECTROSCOPY; NON-KEKULE MOLECULES; GROUND-STATE; METHYLENECYCLOPROPANE REARRANGEMENT; SINGLET-STATES; ORTHO-BENZYNE; P-BENZYNE; GAS-PHASE; ABINITIO CALCULATIONS AB The photoelectron spectrum of the trimethylenemethane (TMM) negative ion is described. The electron affinity of TMM is found from the spectrum to be 0.431 +/- 0.006 eV, and the energy difference between the (X) over tilde (3)A'(2) and (b) over tilde (1)A(1) states of TMM is determined to be 16.1 +/- 0.2 kcal/mol. The energy difference between the lowest energy triplet and singlet states is estimated to be 13-16 kcal/mol. The enthalpy of formation of TMM is measured to be 70 +/- 3 kcal/mol, and the C-H bond enthalpy in 2-methylallyl radical is 90 +/- 2 kcal/mol. Previously unobserved vibrational frequencies of 425, 915, and 1310 cm(-1) are found for the triplet state of TMM, whereas a frequency of 325 cm(-1) is found for the singlet state. In addition, an overtone peak is observed for the triplet state at 1455 cm(-1), and both states contain peaks that are assigned to bands arising from excited vibrational levels of the ion. (J Am Soc Mass Spectrom 1999, 10, 800-809) (C) 1999 American Society for Mass Spectrometry. C1 Texas Tech Univ, Dept Chem & Biochem, Lubbock, TX 79409 USA. Purdue Univ, Dept Chem, W Lafayette, IN 47907 USA. Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. Univ Colorado, Natl Inst Stand & Technol, Boulder, CO 80309 USA. Univ Colorado, Dept Chem & Biochem, Boulder, CO 80309 USA. RP Wenthold, PG (reprint author), Texas Tech Univ, Dept Chem & Biochem, MS 1061, Lubbock, TX 79409 USA. NR 92 TC 35 Z9 35 U1 1 U2 2 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 USA SN 1044-0305 J9 J AM SOC MASS SPECTR JI J. Am. Soc. Mass Spectrom. PD SEP PY 1999 VL 10 IS 9 BP 800 EP 809 DI 10.1016/S1044-0305(99)00043-4 PG 10 WC Chemistry, Analytical; Chemistry, Physical; Spectroscopy SC Chemistry; Spectroscopy GA 232HB UT WOS:000082364200003 ER PT J AU Ralph, FM Neiman, PJ Keller, TL AF Ralph, FM Neiman, PJ Keller, TL TI Deep-tropospheric gravity waves created by leeside cold fronts SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID WIND-PROFILER OBSERVATIONS; CENTRAL UNITED-STATES; MOUNTAIN LEE WAVES; CLEAR-AIR RADAR; NUMERICAL SIMULATIONS; THUNDERSTORM OUTFLOW; ROCKY-MOUNTAINS; WEATHER SYSTEMS; ARCTIC FRONT; VHF RADAR AB The water vapor channel of the Geostationary Operational Environmental Satellite GOES-8 reveals narrow (30 km wide), elongated (500-1000 km) bands that propagate southward on the eastern side of the Rocky Mountains from Colorado to Texas. Two events in which surface and wind profiler observations show that these bands are associated with leeside cold fronts are documented in detail, and several other cases are summarized. The wind profilers observe vertical motions exceeding 1 m s(-1) in narrow plumes at the leading edge of the fronts, in broader zones in the upper troposphere, and in the lower stratosphere. These cause vertical displacements of up to 1 km and are responsible for the signature in water vapor images. The bands occur when the Rocky Mountains block either arctic leeside cold fronts coining from the north or northeast or Pacific cold fronts coming from the northwest. The blocking changes the frontal orientation and disrupts geostrophic thermal wind balance near the terrain-modified fronts. This imbalance is manifested as strong (20 m s(-1)) prefrontal, front-relative, cross-front flow V-r. Observations and numerical simulations are presented showing that deep-tropospheric gravity waves are produced in this region by the obstacle effect of the surface leeside cold front. Farther east, V-r is near zero, and the waves are weak or absent. Along the western portion of the front the waves propagate with the front and resemble trapped lee waves: however, farther east the waves appear ahead of the surface front by up to 100 km. These prefrontal gravity waves occur when the wave forcing decays along the eastern portion of the Dent and the crapped waves that had developed there become decoupled from the front and propagate away. Numerical simulations of a well-observed event confirm that trapped waves would have developed, and profiler data confirm the trapped nature of the observed gravity wave's vertical structure. Such waves could create convection, including prefrontal squall lines, and can be seen in real-time satellite imagery before the convection is triggered. C1 NOAA, ERL, ETL, Boulder, CO 80303 USA. NCAR, Res Applicat Program, Boulder, CO USA. RP Ralph, FM (reprint author), NOAA, ERL, ETL, Mail Code R E ET7,325 Broadway, Boulder, CO 80303 USA. NR 68 TC 14 Z9 14 U1 0 U2 1 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 SEP 1 PY 1999 VL 56 IS 17 BP 2986 EP 3009 DI 10.1175/1520-0469(1999)056<2986:DTGWCB>2.0.CO;2 PG 24 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 236UB UT WOS:000082616500002 ER PT J AU Schneider, JM Lilly, DK AF Schneider, JM Lilly, DK TI An observational and numerical study of a sheared, convective boundary layer. Part I: Phoenix II observations, statistical description, and visualization SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID ELEVATED MIXED-LAYER; SOUTHERN GREAT-PLAINS; ORTHOGONAL FUNCTION-ANALYSIS; DOPPLER RADAR OBSERVATIONS; SYNOPTIC CLIMATOLOGY; TURBULENCE STRUCTURE; VERTICAL-VELOCITY; MATCHING MODELS; DENVER CYCLONE; ROLL VORTICES AB Four-dimensional velocity fields derived from dual Doppler radar observations are the basis of a description and statistical analysis of a convective, sheared planetary boundary layer during an afternoon over the High Plains of eastern Colorado. Mean velocities and momentum fluxes are calculated directly from the radar data and are verified with aircraft and tower data. Perturbation pressure and buoyancy fields are recovered for turbulent kinetic energy budgets, and for estimates of horizontal heat advection across the analysis area. The surface layer and lowest third of the observed boundary layer were similar to minimally sheared convective boundary layers, but there were significant differences in the upper two-thirds of the boundary layer. An overrunning residual mountain boundary layer merged with the locally generated convective boundary layer, producing a deep, continuously sheared layer of turbulent activity. Computer visualization reveals a complicated flow characterized by clusters of vortical structures extending well into the slightly stable overrunning region, frequently dominated by clusters of large, long-lived vortices. First- and second-order statistics vary with time of day and averaging volume, suggesting that appropriate parameterizations of similar boundary layers should be functions of the required spatial and temporal scales and mesoscale environment. A number of common simplifying assumptions, scalings, and parameterizations employed for purely convective boundary layers would be inappropriate for this flow. C1 Natl Severe Storms Lab, Norman, OK 73069 USA. Univ Oklahoma, Sch Meteorol, Norman, OK 73019 USA. RP Schneider, JM (reprint author), ARS, USDA, Grazinglands Res Lab, 7207 W Cheyenne St, El Reno, OK 73036 USA. NR 54 TC 8 Z9 8 U1 0 U2 3 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 SEP 1 PY 1999 VL 56 IS 17 BP 3059 EP 3078 DI 10.1175/1520-0469(1999)056<3059:AOANSO>2.0.CO;2 PG 20 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 236UB UT WOS:000082616500006 ER PT J AU Kim, YK Indelicato, P Desclaux, JP AF Kim, YK Indelicato, P Desclaux, JP TI Failure of single-configuration Dirac-Fock wave functions in the nonrelativistic limit SO JOURNAL OF THE KOREAN PHYSICAL SOCIETY LA English DT Article; Proceedings Paper CT 6th Symposium on Laser Spectroscopy CY NOV 03-04, 1998 CL KOREA ATOM ENERGY RES INST, TAEJON, SOUTH KOREA HO KOREA ATOM ENERGY RES INST ID MULTICONFIGURATION AB We have found earlier that a certain type of multiconfiguration Dirac-Fock wave functions may not have the correct nonrelativistic limit in the spin quantum number, and hence may result in large errors in the transition probabilities for spin-forbidden, weak transitions. In this article, we report that the failure to have the correct nonrelativistic limit can also occur in a certain type of single-configuration Dirac-Fock wave functions. Examples of such a case, along with an effective remedy, are illustrated using the spin-forbidden transitions, 2p(4) 3s P-4 --> 2p(5) P-2, in F and Ne+. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Ecole Normale Super, Lab Kastler Brossel, F-75252 Paris 5, France. Univ Paris 06, F-75252 Paris 5, France. CEA Grenoble, Direct Sci Matiere, F-38054 Grenoble 9, France. RP Kim, YK (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RI Indelicato, Paul/D-7636-2011 OI Indelicato, Paul/0000-0003-4668-8958 NR 3 TC 1 Z9 1 U1 0 U2 0 PU KOREAN PHYSICAL SOC PI SEOUL PA 635-4, YUKSAM-DONG, KANGNAM-KU, SEOUL 135-703, SOUTH KOREA SN 0374-4884 J9 J KOREAN PHYS SOC JI J. Korean Phys. Soc. PD SEP PY 1999 VL 35 IS 3 BP 165 EP 167 PG 3 WC Physics, Multidisciplinary SC Physics GA 235XQ UT WOS:000082569500009 ER PT J AU Ilavsky, J Long, GG Allen, AJ Leblanc, L Prystay, M Moreau, C AF Ilavsky, J Long, GG Allen, AJ Leblanc, L Prystay, M Moreau, C TI Anisotropic microstructure of plasma-sprayed deposits SO JOURNAL OF THERMAL SPRAY TECHNOLOGY LA English DT Reprint DE alumina; anisotropy; image analysis; microstructure; small angle neutron scattering; thermally sprayed deposits; yttria-stabilized zirconia ID COATINGS AB The microstructure of plasma sprayed deposits (PSD) is dominated by two void systems-interlamellar pores and intralamellar cracks-each with a different anisotropy, Anisotropy of these void systems and varying crack-to-pore ratios within PSDs are responsible for the anisotropic properties observed within deposits. While it is difficult to apply standard porosity measurement techniques to the assessment of anisotropic microstructures, novel techniques utilizing different approaches have recently emerged. Image analysis (IA) of impregnated PSD samples is the most direct technique. The structure is stabilized by impregnation and then polished and imaged. The limitations of IA lie in the impregnation process and in the subsequent polishing. Also, the images produced from anisotropic materials can be difficult to interpret quantitatively. The technique of small-angle neutron scattering (SANS) has recently been applied to the study of PSDs, The major advantages of SANS are that it does not require sample preparation and that quantitative information can be obtained concerning the separate crack and pore systems, including their distinctive anisotropies. However, the relationship between the SANS results and the underlying structure is more complex and less intuitive than for IA, and the availability of the SANS technique is limited by the need to have access to a powerful neutron source, such as a reactor. Also, the two techniques present different views of the microstructure because of the different sensitivities in different parts of the size range. This article compares results from IA and SANS for a set of thick plasma-sprayed ceramic deposits possessing a range of crack/pore microstructures and discusses how the two techniques might complement one another. C1 AV CR, Inst Plasma Phys, Prague, Czech Republic. US Dept Commerce, Natl Inst Stand & Technol, Gaithersburg, MD USA. Natl Res Council, Boucherville, PQ, Canada. RP Ilavsky, J (reprint author), US Dept Commerce, Natl Inst Stand & Technol, 100 Bur Dr Stop 8523, Gaithersburg, MD USA. OI Ilavsky, Jan/0000-0003-1982-8900 NR 22 TC 8 Z9 9 U1 0 U2 0 PU ASM INTERNATIONAL PI MATERIALS PARK PA SUBSCRIPTIONS SPECIALIST CUSTOMER SERVICE, MATERIALS PARK, OH 44073-0002 USA SN 1059-9630 J9 J THERM SPRAY TECHN JI J. Therm. Spray Technol. PD SEP PY 1999 VL 8 IS 3 BP 414 EP 420 DI 10.1361/105996399770350368 PG 7 WC Materials Science, Coatings & Films SC Materials Science GA 233PB UT WOS:000082434300008 ER PT J AU Hiruki, LM Schwartz, MK Boveng, PL AF Hiruki, LM Schwartz, MK Boveng, PL TI Hunting and social behaviour of leopard seals (Hydrurga leptonyx) at Seal Island, South Shetland Islands, Antarctica SO JOURNAL OF ZOOLOGY LA English DT Article DE leopard seal; Hydrurga leptonyx; hunting behaviour; social behaviour; predation ID WHALES ORCINUS-ORCA; ARCTOCEPHALUS-GAZELLA; FUR SEALS; KILLER WHALES; ZALOPHUS-CALIFORNIANUS; SEASONAL OCCURRENCE; CRABEATER SEALS; HEARD-ISLAND; BIRD ISLAND; CRAB-EATER AB The hunting behaviour of leopard seals Hydrurga leptonyx was monitored opportunistically at Seal Island, South Shetland Islands, during the austral summers from 1986/87 to 1994/95. Leopard seals used several methods to catch Antarctic fur seal pups Arctocephalus gazella and chinstrap penguins Pygoscelis antarctica, and individuals showed different hunting styles and hunting success. One to two leopard seals per year were responsible for an average of 60% of observed captures of fur seal pups. Leopard seals preyed on penguins throughout the summer, but preyed on fur seal pups only between late December and mid-February. Hunting behaviour differed significantly between different locations on the island; fur seals were hunted only at one colony, and penguins were hunted in several areas. The relative abundance of prey types, size of prey in relation to predator, and specialization of individual leopard seals to hunt fur seal prey probably influence individual prey preferences among leopard seals. On five occasions, two leopard seals were seen together on Seal Island. Possible interpretations of the relationship between the interacting leopard seals included a mother-offspring relationship, a consorting male-female pair, and an adult leopard seal followed by an unrelated juvenile. In two incidents at Seal Island, two leopard seals were observed interacting while hunting: one seal captured fur seal pulps and appeared to release them to the other seal. Observations of leopard seals interacting during hunting sessions were difficult to confirm as co-operative hunting, but they strongly implied that the two seals were not agonistic toward one another. The hunting success of individual leopard seals pursuing penguins or fur seals is probably high enough for co-operative hunting not to become a common hunting strategy; however, it may occur infrequently when it increases the hunting productivity of the seals. C1 NOAA, Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr, Natl Marine Mammal Lab, Seattle, WA 98115 USA. RP Hiruki, LM (reprint author), NOAA, Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr, Natl Marine Mammal Lab, 7600 Sand Point Way NE,Bldg 4, Seattle, WA 98115 USA. RI Schwartz, Michael/C-3184-2014 OI Schwartz, Michael/0000-0003-3521-3367 NR 73 TC 26 Z9 27 U1 22 U2 62 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 40 WEST 20TH STREET, NEW YORK, NY 10011-4211 USA SN 0952-8369 J9 J ZOOL JI J. Zool. PD SEP PY 1999 VL 249 BP 97 EP 109 PN 1 PG 13 WC Zoology SC Zoology GA 241MW UT WOS:000082888000009 ER PT J AU Armstrong, RA AF Armstrong, RA TI An optimization-based model of iron-light-ammonium colimitation of nitrate uptake and phytoplankton growth SO LIMNOLOGY AND OCEANOGRAPHY LA English DT Article ID SUB-ARCTIC PACIFIC; EQUATORIAL PACIFIC; MARINE-PHYTOPLANKTON; CONTINUOUS CULTURE; SOUTHERN-OCEAN; ECOSYSTEM MODEL; LIMITED ECOSYSTEM; LIMITATION; NITROGEN; PRODUCTIVITY AB The ability to model "new" (nitrate-based) production is crucial to predicting the ocean's role in the global carbon cycle. The ability to model the distribution of high-nutrient/low-chlorophyll (HNLC) areas is particularly important in this regard. Here I draw together three elements that appear to be necessary for constructing the required model: (1) iron limitation of algal growth rates as an ultimate cause of the HNLC condition; (2) ammonium inhibition of nitrate uptake and utilization as a proximate mechanism that leads to reduced nitrate use; and (3) the dependence of both processes on algal cell size. In the model, cells are postulated to maximize their growth rates by partitioning scarce iron between nitrogen- and carbon-related demands. The: effect of iron limitation is postulated to depend on cell size through surface/volume effects on uptake efficiency; this dependence on cell size in turn affects phytoplankton community structure and community-level uptake of nitrate. The efficacy of the model is demonstrated by its ability to reproduce community-level curves of nitrate uptake versus ammonium concentration from both HNLC and non-HNLC areas. The partition formalism can be incorporated directly into ecosystem models; when implemented in an ecosystem model with multiple size classes, the model should produce HNLC versus non-HNLC conditions in appropriate locations and for appropriate reasons. In particular, the model's ability to produce iron-light and iron-light-nitrogen colimitation should be useful in understanding and predicting the HNLC condition in parts of the Southern Ocean. With suitable changes to parameter values, the postulated mechanism for iron partitioning may also prove useful in modeling iron and energy partitioning in nitrogen fixers. C1 Princeton Univ, Program Atmospher & Ocean Sci, Princeton, NJ 08544 USA. RP Armstrong, RA (reprint author), Princeton Univ, Program Atmospher & Ocean Sci, Sayre Hall,POB CN710, Princeton, NJ 08544 USA. RI Armstrong, Robert/C-9086-2009 NR 57 TC 44 Z9 47 U1 0 U2 13 PU AMER SOC LIMNOLOGY OCEANOGRAPHY PI WACO PA 5400 BOSQUE BLVD, STE 680, WACO, TX 76710-4446 USA SN 0024-3590 J9 LIMNOL OCEANOGR JI Limnol. Oceanogr. PD SEP PY 1999 VL 44 IS 6 BP 1436 EP 1446 PG 11 WC Limnology; Oceanography SC Marine & Freshwater Biology; Oceanography GA 229PA UT WOS:000082201900008 ER PT J AU Holland, KN Wetherbee, BM Lowe, CG Meyer, CG AF Holland, KN Wetherbee, BM Lowe, CG Meyer, CG TI Movements of tiger sharks (Galeocerdo cuvier) in coastal Hawaiian waters SO MARINE BIOLOGY LA English DT Article ID SHORTFIN MAKO SHARK; VERTICAL MOVEMENTS; CARCHARHINUS-AMBLYRHYNCHOS; ISURUS-OXYRINCHUS; THUNNUS-ALBACARES; PRIONACE-GLAUCA; SPHYRNA-LEWINI; YELLOWFIN TUNA; PATTERNS; CALIFORNIA AB Externally and internally implanted sonic transmitters were used to track the movements of eight tiger sharks (Galeocerdo cuvier) ranging between 200 and 417 cm total length (TL), captured by hook-and-line on the south coast of Oahu, Hawaii, between 1993 and 1997. Attachment of the transmitters was facilitated by the fact that captured sharks exhibited tonic immobility when restrained and inverted at the side of the tagging vessel. Three common themes emerged from the horizontal movements of the tracked sharks: (1) offshore movements away from the island, (2) extended periods of directed, "straight-line" swimming, (3) orientation to the Penguin Banks - a shallow bank located similar or equal to 35 km from the release point. In shallow water (<300 m) the sharks swam predominantly close to the bottom, in open water (>300 m)they swam within the mixed layer at depths of similar to 80 m. One shark dove briefly to 335 m. The average estimated swimming speed of sharks traversing open water was 0.29 body length (BL) s(-1). Two sharks were recaptured after termination of the tracks; one of these sharks was recaptured twice, with a total time at liberty of 377 d. The data suggest that Hawaiian tiger sharks move within large home ranges and that they can efficiently navigate between distant parts of their range, even when this requires crossing open ocean waters. C1 Univ Hawaii Manoa, Hawaii Inst Marine Biol, Kaneohe, HI 96744 USA. NOAA, Natl Marine Fisheries Serv, NESC, Narragansett, RI 02882 USA. Univ Hawaii Manoa, Dept Zool, Honolulu, HI 96822 USA. Univ Hawaii Manoa, Hawaii Inst Marine Biol, Honolulu, HI 96822 USA. RP Holland, KN (reprint author), Univ Hawaii Manoa, Hawaii Inst Marine Biol, POB 1346, Kaneohe, HI 96744 USA. NR 32 TC 103 Z9 107 U1 5 U2 34 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0025-3162 J9 MAR BIOL JI Mar. Biol. PD SEP PY 1999 VL 134 IS 4 BP 665 EP 673 DI 10.1007/s002270050582 PG 9 WC Marine & Freshwater Biology SC Marine & Freshwater Biology GA 237BG UT WOS:000082633300008 ER PT J AU Brierley, AS Demer, DA Watkins, JL Hewitt, RP AF Brierley, AS Demer, DA Watkins, JL Hewitt, RP TI Concordance of interannual fluctuations in acoustically estimated densities of Antarctic krill around South Georgia and Elephant Island: biological evidence of same-year teleconnections across the Scotia Sea SO MARINE BIOLOGY LA English DT Article ID EUPHAUSIA-SUPERBA DANA; FISH STOCKS; VARIABILITY; RECRUITMENT; ABUNDANCE; ATLANTIC; OCEAN AB Acoustic estimates of the densities of Antarctic krill, Euphausia superba, in areas around South Georgia (SG) and Elephant Island (EI) were compared for seven austral summers between 1981 and 1997. Estimated densities of krill at SG were most often lower than at EI, although this may simply have been a function of differences in the survey and data-analysis techniques used at each site. More interestingly, the magnitudes of density and between-year gradients of density at each site were mirrored by those at the other location; for example 1991 and 1994 were years of very low krill density at both SG and EI. There was no apparent lag in changes in density between sites, and ranked between-year gradients in density at both locations were closely correlated. These pronounced similarities suggest that densities of krill at both locations are linked directly, and may be impacted by the same gross physical and biological factors (e.g. recruitment, dispersal and environmental variability) acting over the same temporal and spatial scales. The observed concordance also implies that the pelagic ecosystems at these widely separated sites (similar or equal to 1500 km distant at opposite sides of the Scotia Sea) are not operating in isolation. Fluctuations in krill density were investigated with reference to cyclical variations in sea ice extent, and in air and sea-surface temperature. The resulting model suggests that the 1999/2000 austral summer will be one of low krill density. C1 British Antarctic Survey, Cambridge CB3 0ET, England. SW Fisheries Sci Ctr, La Jolla, CA 92038 USA. RP Brierley, AS (reprint author), British Antarctic Survey, High Cross,Madingley Rd, Cambridge CB3 0ET, England. RI Brierley, Andrew/G-8019-2011 OI Brierley, Andrew/0000-0002-6438-6892 NR 34 TC 58 Z9 61 U1 0 U2 3 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0025-3162 J9 MAR BIOL JI Mar. Biol. PD SEP PY 1999 VL 134 IS 4 BP 675 EP 681 DI 10.1007/s002270050583 PG 7 WC Marine & Freshwater Biology SC Marine & Freshwater Biology GA 237BG UT WOS:000082633300009 ER PT J AU O'Connor, TP AF O'Connor, TP TI A wider look at the risk of ocean disposal of dredged material SO MARINE POLLUTION BULLETIN LA English DT Editorial Material C1 NOAA, NSCI1, Natl Status & Trends Program, Silver Spring, MD 20910 USA. RP NOAA, NSCI1, Natl Status & Trends Program, 1305 E W Highway, Silver Spring, MD 20910 USA. EM tom.oconnor@noaa.gov NR 6 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 0025-326X EI 1879-3363 J9 MAR POLLUT BULL JI Mar. Pollut. Bull. PD SEP PY 1999 VL 38 IS 9 BP 760 EP 761 DI 10.1016/S0025-326X(99)00128-9 PG 2 WC Environmental Sciences; Marine & Freshwater Biology SC Environmental Sciences & Ecology; Marine & Freshwater Biology GA 249DY UT WOS:000083318600013 ER PT J AU Sun, LC AF Sun, LC TI Data inter-operability driven by oceanic data assimilation needs SO MARINE TECHNOLOGY SOCIETY JOURNAL LA English DT Article AB An interactive data access and retrieval system, developed at the U.S. National Oceanographic Data Center (NODC) and available at http://www.node.noaa.gov, is presented in this paper. The purposes of this paper are: (1) to illustrate the procedures of quality control and loading oceanographic data into the NODC ocean data-bases and (2) to describe the development of a system to manage, visualize, and disseminate the NODC data holdings over the Internet. The objective of the system is to provide ease of access to data that will be required for data assimilation models. With advances in scientific understanding of the ocean dynamics, data assimilation models require the synthesis of data from a variety of resources. Modem. intelligent data systems usually involve integrating distributed heterogeneous data and information sources. As the repository for oceanographic data, NOAA's National Oceanographic Data Center (NODC) is in a unique position to develop such a data system. In support of the data assimilation needs, NODC has developed a system to facilitate browsing of the oceanographic environmental data and information that is available on-line at NODC. Users may select oceanographic data based on geographic areas, time periods and measured parameters. Once the selection is complete, users may produce a station location plot, produce plots of the parameters or retrieve the data. C1 NOAA, Coastal Ocean Lab, Natl Oceanog Data Ctr, NESDIS, Silver Spring, MD 20910 USA. RP Sun, LC (reprint author), NOAA, Coastal Ocean Lab, Natl Oceanog Data Ctr, NESDIS, Silver Spring, MD 20910 USA. NR 6 TC 4 Z9 4 U1 0 U2 0 PU MARINE TECHNOLOGY SOC INC PI WASHINGTON PA C/O I CLAYION MATTHEWS, 1828 L ST, NW, 9TH FL, WASHINGTON, DC 20036 USA SN 0025-3324 J9 MAR TECHNOL SOC J JI Mar. Technol. Soc. J. PD FAL PY 1999 VL 33 IS 3 BP 55 EP 66 PG 12 WC Engineering, Ocean; Oceanography SC Engineering; Oceanography GA 255AY UT WOS:000083648400007 ER PT J AU Tseng, WF Monk, DH AF Tseng, WF Monk, DH TI Subthreshold characteristics of laterally gated AlGaAs/InGaAs pseudomorphic high-electron-mobility transistors fabricated with focused ion beam implantation SO MATERIALS LETTERS LA English DT Article DE focused ion beam (FIB); field-effect transistor (FET); AlGaAs; DX centers ID GAAS AB We have used a focused ion beam (FIB) technique to fabricate laterally gated AlGaAs/InGaAs pseudomorphic high-electron-mobility transistors (pHEMTs), and have characterized them electrically. The FIB direct-write defines the current path. An ion dose of 1 X 10(14) ions cm(-2) from a 25 keV Ga+ beam gives satisfactory electrical isolation. The fabricated transistors show typical field-effect transistor (FET) characteristics. For a properly adjusted n-AlGaAs layer, transfer characteristics. (I-ds, vs. V-g) in the subthreshold region show gate leakage similar to that of metal-semiconductor FETs. For the thicker n-AlGaAs layer, the subthreshold transfer characteristic shows additional conduction with sporadic current-spikes. We attribute the cause of sporadic current-spikes to deep donors or DX centers in the silicon-doped AlGaAs layer. (C) 1999 Elsevier Science B,V. All rights reserved. C1 Natl Inst Stand & Technol, Div Semicond Elect, Gaithersburg, MD 20899 USA. RP Tseng, WF (reprint author), Natl Inst Stand & Technol, Div Semicond Elect, 100 Bur Dr,Stop 8121, Gaithersburg, MD 20899 USA. NR 10 TC 2 Z9 2 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0167-577X J9 MATER LETT JI Mater. Lett. PD SEP PY 1999 VL 40 IS 5 BP 235 EP 239 DI 10.1016/S0167-577X(99)00081-6 PG 5 WC Materials Science, Multidisciplinary; Physics, Applied SC Materials Science; Physics GA 241MU UT WOS:000082887800006 ER PT J AU Almond, PR Biggs, PJ Coursey, BM Hanson, WF Huq, MS Nath, R Rogers, DWO AF Almond, PR Biggs, PJ Coursey, BM Hanson, WF Huq, MS Nath, R Rogers, DWO TI AAPM's TG-51 protocol for clinical reference dosimetry of high-energy photon and electron beams SO MEDICAL PHYSICS LA English DT Article ID STOPPING-POWER RATIOS; IONIZATION CHAMBERS; RECOMBINATION CORRECTION; QUALITY SPECIFICATION; PLANE-PARALLEL; ION-CHAMBER; RADIATION; CALIBRATION; COLLECTION; THIMBLE AB A protocol is prescribed for clinical reference dosimetry of external beam radiation therapy using photon beams with nominal energies between Co-60 and 50 MV and electron beams with nominal energies between 4 and 50 MeV. The protocol was written by Task Group 51 (TG-51) of the Radiation Therapy Committee of the American Association of Physicists in Medicine (AAPM) and has been formally approved by the AAPM for clinical use. The protocol uses ion chambers with absorbed-dose-to-water calibration factors, N-D,w(60Co), which are traceable to national primary standards, and the equation D-w(Q) = Mk(Q)N(D,w)(60Co), where Q is the beam quality of the clinical beam, DP is the absorbed dose to water at the point of measurement of the ion chamber placed under reference conditions, M is the fully corrected ion chamber reading, and kg is the quality conversion factor which converts the calibration factor for a Co-60 beam to that for a beam of quality Q. Values of ka are presented as a function of Q for many ion chambers. The value of M is given by M = PionPTPPelecPpolMraw, where M-raw is the raw, uncorrected ion chamber reading and P-ion corrects for ion recombination, P-TP for temperature and pressure variations, P-elec for inaccuracy of the electrometer if calibrated separately, and P-pol for chamber polarity effects. Beam quality, Q, is specified (i) for photon beams, by %dd(10)(x), the photon component of the percentage depth dose at 10 cm depth for a field size of 10 x 10 cm(2) on the surface of a phantom at an SSD of 100 cm and (ii) for electron beams, by R-50, the depth at which the absorbed-dose falls to 50% of the maximum dose in a beam with field size greater than or equal to 10 x 10 cm(2) on the surface of the phantom (greater than or equal to 20 x 20 cm(2) for R-50> 8.5 cm) at an SSD of 100 cm. R-50 is determined directly from the measured value of I-50, the depth at which the ionization falls to 50% of its maximum value. All clinical reference dosimetry is performed in a water phantom. The reference depth for calibration purposes is 10 cm for photon beams and 0.6R(50)-0.1 cm for electron beams. For photon beams clinical reference dosimetry is performed in either an SSD or SAD setup with a 10 x 10 cm(2) field size defined on the phantom surface for an SSD setup or at the depth of the detector for an SAD setup. For electron beams clinical reference dosimetry is performed with a field size of greater than or equal to 10 x 10 cm(2) (greater than or equal to 20 x 20 cm(2) for R-50> 8.5 cm) at an SSD between 90 and 110 cm. This protocol represents a major simplification compared to the AAPM's TG-21 protocol in the sense that large tables of stopping-power ratios and mass-energy absorption coefficients are not needed and the user does not need to calculate any theoretical dosimetry factors. Worksheets for various situations are presented along with a list of equipment required. (C) 1999 American Association of Physicists in Medicine. [S0094-2405(99)00209-6]. C1 Brown Canc Ctr, Louisville, KY 40202 USA. Massachusetts Gen Hosp, Dept Radiat Oncol, Boston, MA 02114 USA. Natl Inst Stand & Technol, Ionizing Radiat Div, Gaithersburg, MD 20899 USA. Univ Texas, MD Anderson Canc Ctr, Houston, TX 77030 USA. Thomas Jefferson Univ, Jefferson Med Coll, Kimmel Canc Ctr, Philadelphia, PA 19107 USA. Yale Univ, Sch Med, New Haven, CT 06510 USA. Natl Res Council Canada, Ottawa, ON K1A 0R6, Canada. RP Almond, PR (reprint author), Brown Canc Ctr, Louisville, KY 40202 USA. RI Rogers, David/A-1973-2008; Grams, Michael/G-5197-2011 NR 52 TC 616 Z9 629 U1 2 U2 26 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0094-2405 J9 MED PHYS JI Med. Phys. PD SEP PY 1999 VL 26 IS 9 BP 1847 EP 1870 DI 10.1118/1.598691 PG 24 WC Radiology, Nuclear Medicine & Medical Imaging SC Radiology, Nuclear Medicine & Medical Imaging GA 237AV UT WOS:000082632200016 PM 10505874 ER PT J AU Newbury, DE Bright, DS AF Newbury, DE Bright, DS TI Logarithmic 3-band color encoding: Robust method for display and comparison of compositional maps in electron probe X-ray microanalysis SO MICROSCOPY AND MICROANALYSIS LA English DT Article DE digital image; compositional map; feature visibility; log color scale; logarithmic 3-band color scale; X-ray map; X-ray microanalysis ID MACINTOSH; PROGRAM; IMAGE AB Electron-excited X-ray maps recorded with the scanning electron microscope (SEM)/electron probe X-ray microanalyzer (EPMA) are a major method of presenting compositional information. Digitally recorded maps are processed in a variety of ways to improve the visibility of features. Scaling of the recorded signal to match the 8-bit gray-scale intensity range of a typical computer display system is almost always necessary. Inherent limitations of gray-scale displays have led to other intensity-encoding methods for X-ray maps, including clipping, histogram normalization, and pseudocolor scales. While feature visibility is improved by applying these scales, comparisons among image sets are difficult. Quantitative comparisons must be based on standardized intensities corrected for background to produce intensity ratio (k-value) maps. We have developed a new logarithmic, multiband color-encoding method to view these k-value maps more effectively. Three color bands are defined, starting with a dark primary color and grading to a bright pastel: blue = trace (0.001 to 0.01); green = minor (0.01 to 0.1); and red = major (0.1 to 1.0). Within each band, the color is assigned according to a logarithmic scale that depends on intensity ratio or compositional measurements. Logarithmic multiband color encoding permits direct comparisons of maps, such as maps of different elements in the same field of view or maps of the same element in different areas, because the color scale is identical for all maps. C1 Natl Inst Stand & Technol, Surface & Microanalyt Sci Div, Gaithersburg, MD 20899 USA. RP Newbury, DE (reprint author), Natl Inst Stand & Technol, Surface & Microanalyt Sci Div, Gaithersburg, MD 20899 USA. NR 9 TC 12 Z9 12 U1 0 U2 3 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 1431-9276 J9 MICROSC MICROANAL JI Microsc. microanal. PD SEP-OCT PY 1999 VL 5 IS 5 BP 333 EP 343 PG 11 WC Materials Science, Multidisciplinary; Microscopy SC Materials Science; Microscopy GA 233NJ UT WOS:000082432700001 ER PT J AU Rappaport, EN AF Rappaport, EN TI Atlantic hurricane season of 1997 SO MONTHLY WEATHER REVIEW LA English DT Article ID EL-NINO AB The 1997 Atlantic hurricane season is summarized and the year's tropical storms, hurricanes, and one subtropical storm are described. The tropical cyclones were relatively few in number, short lived, and weak compared to long-term climatology. Most systems originated outside the deep Tropics. Hurricane Danny was the only system to make landfall. It produced rainfall totals to near 1 m in southern Alabama and is blamed for live deaths. Hurricane Erika was responsible for the season's two other fatalities, in the coastal waters of Puerto Rico. C1 NOAA, NWS, Natl Hurricane Ctr, Trop Predict Ctr, Miami, FL 33165 USA. RP Rappaport, EN (reprint author), NOAA, NWS, Natl Hurricane Ctr, Trop Predict Ctr, 11691 SW 17th St, Miami, FL 33165 USA. NR 12 TC 13 Z9 13 U1 0 U2 2 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0027-0644 J9 MON WEATHER REV JI Mon. Weather Rev. PD SEP PY 1999 VL 127 IS 9 BP 2012 EP 2026 DI 10.1175/1520-0493(1999)127<2012:AHSO>2.0.CO;2 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 240XD UT WOS:000082851600006 ER PT J AU Darby, LS Neff, WD Banta, RM AF Darby, LS Neff, WD Banta, RM TI Multiscale analysis of a meso-beta frontal passage in the complex terrain of the Colorado front range SO MONTHLY WEATHER REVIEW LA English DT Article ID PULSED DOPPLER LIDAR; GRAVITY CURRENT; COLD-FRONT; MESOSCALE; MODEL; DISPERSION; RADAR; FLOWS; CLOUD AB Data from a mesoscale observing network are used to describe the evolution of a complex boundary between a dry air mass near the foothills of the Rocky Mountains and a shallow moist air mass over the eastern plains. Synoptic-scale analyses revealed that the origin of the moist air mass was associated with lee cyclogenesis. Mesoscale analyses provided a detailed picture of a localized anticyclonic circulation that developed within the larger-scale how. Mixing ratio data from the mesoscale observing network indicated the position of the boundary between the air masses. It is shown that the cooler, moister air on the plains advanced toward and retreated away from the foothills during the evening. Eventually, downslope winds that were opposing the motion of the mesoscale boundary decreased, and the anticyclonic circulation on the plains became more organized. On an even smaller scale, Doppler lidar measurements revealed characteristics of the wind flow associated with the mesofront and the interaction of this flow with the downslope winds near the foothills of the Rocky Mountains. These characteristics included the horizontal variability of the winds near the complex foothills topography; the vertical structure of the winds associated with the mesofront, which indicated density-current-like features; the vertical structure of strong downslope flow opposing the mesofront's motion; and differences in the aerosol content of the air masses. C1 NOAA, Environm Res Labs, Environm Technol Lab, Boulder, CO 80303 USA. RP Darby, LS (reprint author), NOAA, Environm Res Labs, Environm Technol Lab, R E ET2,325 Broadway, Boulder, CO 80303 USA. RI Darby, Lisa/A-8037-2009; Banta, Robert/B-8361-2008; Neff, William/E-2725-2010 OI Darby, Lisa/0000-0003-1271-0643; Neff, William/0000-0003-4047-7076 NR 27 TC 11 Z9 11 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0027-0644 J9 MON WEATHER REV JI Mon. Weather Rev. PD SEP PY 1999 VL 127 IS 9 BP 2062 EP 2081 DI 10.1175/1520-0493(1999)127<2062:MAOAMF>2.0.CO;2 PG 20 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 240XD UT WOS:000082851600009 ER PT J AU Neiman, PJ Wakimoto, RM AF Neiman, PJ Wakimoto, RM TI The interaction of a Pacific cold front with shallow air masses east of the Rocky Mountains SO MONTHLY WEATHER REVIEW LA English DT Article ID DOPPLER WEATHER RADAR; CENTRAL UNITED-STATES; BOUNDARY-LAYER; PROFILER OBSERVATIONS; FINESCALE STRUCTURE; CONCEPTUAL-MODEL; SURFACE-ANALYSIS; WINTER CYCLONES; GRAVITY CURRENT; LIFE-CYCLE AB The study presented here describes the interactions that occurred between an advancing Pacific cold front and shallow Gulf of Mexico and Arctic air masses situated east of the Rocky Mountains during the Verification of the Origins of Rotation in Tornadoes Experiment (VORTEX) field campaign on 17-18 April over Oklahoma and adjacent states. These interactions were driven largely by the complex topography of the region. Four air masses of distinctly different origin (i.e., Pacific polar, high-altitude continental, Gulf of Mexico, and Arctic), and the boundaries that separated them (i.e., Pacific cold front, dryline, and Arctic front), were observed within the experimental domain. This event produced more than $ 1 million worth of damage in the experimental domain due to severe weather. A dense network of ground-based in situ and remote observing systems and two research aircraft equipped with in situ sensors and Doppler radars gathered data that allowed the authors to document the passage of a vigorous midtropospheric shortwave trough and associated Pacific cold front, and the interaction of this front with the preexisting Gulf of Mexico and Arctic air masses. The Pacific front intersected the ground to the west of the Arctic frontal boundary and dryline, and subsequently rode over the top of the Gulf of Mexico and Arctic air masses. This study also presents the detailed observational documentation of a dryline-frontal merger by showing the merging or phasing of updrafts associated with the Pacific front and dryline and the subsequent development of a squall line. The behavior of the Arctic front is also explored in detail. Its anomalous southward penetration into the VORTEX domain due to terrain-induced blocking also played a role in producing severe weather. C1 NOAA, ETL, Boulder, CO 80303 USA. Univ Calif Los Angeles, Dept Atmospher Sci, Los Angeles, CA 90024 USA. RP Neiman, PJ (reprint author), NOAA, ETL, Code R E ET7,325 Broadway, Boulder, CO 80303 USA. NR 65 TC 22 Z9 22 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0027-0644 J9 MON WEATHER REV JI Mon. Weather Rev. PD SEP PY 1999 VL 127 IS 9 BP 2102 EP 2127 DI 10.1175/1520-0493(1999)127<2102:TIOAPC>2.0.CO;2 PG 26 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 240XD UT WOS:000082851600011 ER PT J AU Nielsen-Gammon, JW Schultz, DM AF Nielsen-Gammon, JW Schultz, DM TI Comments on "The intensification of the low-level jet during the development of mesoscale convective systems on a Mei-Yu front" SO MONTHLY WEATHER REVIEW LA English DT Letter ID AGEOSTROPHIC CIRCULATIONS; BAROCLINIC DISTURBANCES; INSTABILITY C1 Texas A&M Univ, Dept Meteorol, College Stn, TX 77843 USA. Natl Severe Storms Lab, Norman, OK 73069 USA. RP Nielsen-Gammon, JW (reprint author), Texas A&M Univ, Dept Meteorol, MS 3150, College Stn, TX 77843 USA. RI Schultz, David M./A-3091-2010; Nielsen-Gammon, John/G-9771-2012 OI Schultz, David M./0000-0003-1558-6975; Nielsen-Gammon, John/0000-0001-5336-2409 NR 11 TC 0 Z9 0 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0027-0644 J9 MON WEATHER REV JI Mon. Weather Rev. PD SEP PY 1999 VL 127 IS 9 BP 2227 EP 2231 DI 10.1175/1520-0493(1999)127<2227:COTIOT>2.0.CO;2 PG 5 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 240XD UT WOS:000082851600020 ER PT J AU Tsurutani, BT Lakhina, GS Smith, EJ Buti, B Moses, SL Coroniti, FV Brinca, AL Slavin, JA Zwickl, RD AF Tsurutani, BT Lakhina, GS Smith, EJ Buti, B Moses, SL Coroniti, FV Brinca, AL Slavin, JA Zwickl, RD TI Mirror mode structures and ELF plasma waves in the Giacobini-Zinner magnetosheath SO NONLINEAR PROCESSES IN GEOPHYSICS LA English DT Article ID LOWER-HYBRID WAVES; SOLAR-WIND PLASMA; LION ROARS; STOCHASTIC ACCELERATION; EARTHS MAGNETOSHEATH; MAGNETIC-FIELD; INSTABILITY; MECHANISM; ULYSSES; MAGNETOSPHERE AB We show evidence for mirror mode structures at comet Giacobini-Zinner. These are plasma structures with alternating high beta and low beta regions driven unstable when beta(perpendicular to)/beta(parallel to) > 1+1/beta(perpendicular to). These structures are detected in a region just adjacent to the magnetic tail and have scale sizes of similar to 12 H2O group ion cyclotron radii. Calculations are presented to show that mirror mode instability can occur due to the perpendicular pressure associated with H2O+ cometary pickup ions in the region of minor mode observation. Adjacent regions tin the magnetic tail and further in the sheath) are found to be stable to the mirror mode. Plasma waves are detected in relation with the mirror mode structures. Low frequency 56 to 100 Hz waves are present in the high beta portions, and high frequency, 311 Hz to 10 kHz, waves are present in low beta regions. These may be electromagnetic lion roar waves and electrostatic festoon-shaped waves, respectively, in analogy to plasma waves detected in the Earth's magnetosheath. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91103 USA. Indian Inst Geomagnetism, Bombay 400005, Maharashtra, India. TRW Syst, Redondo Beach, CA USA. Univ Tecn Lisboa, Inst Super Tecn, Ctr Fis Plasmas, Lisbon, Portugal. Goddard Space Flight Ctr, Greenbelt, MD USA. NOAA, Space Environm Lab, Boulder, CO 80303 USA. RP Tsurutani, BT (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91103 USA. RI Lakhina, Gurbax /C-9295-2012; Slavin, James/H-3170-2012; OI Slavin, James/0000-0002-9206-724X; Lakhina, Gurbax /0000-0002-8956-486X NR 44 TC 21 Z9 21 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 SEP-DEC PY 1999 VL 6 IS 3-4 BP 229 EP 234 PG 6 WC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences SC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences GA 306FR UT WOS:000086587100012 ER PT J AU Chang, MMT Day, GW AF Chang, MMT Day, GW TI Your tax dollars are working hard at NIST SO PHOTONICS SPECTRA LA English DT Editorial Material C1 Natl Inst Stand & Technol, Div Optoelect, Boulder, CO 80309 USA. Natl Inst Stand & Technol, Off Optoelect Programs, Boulder, CO USA. RP Chang, MMT (reprint author), Natl Inst Stand & Technol, Div Optoelect, Boulder, CO 80309 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU LAURIN PUBL CO INC PI PITTSFIELD PA BERKSHIRE COMMON PO BOX 1146, PITTSFIELD, MA 01202 USA SN 0731-1230 J9 PHOTON SPECTRA JI Photon. Spect. PD SEP PY 1999 VL 33 IS 9 BP 78 EP 79 PG 2 WC Optics SC Optics GA 233WA UT WOS:000082449100036 ER PT J AU Kasper, NV Troyanchuk, IO Khalyavin, DD Hamad, N Haupt, L Frobel, P Barner, K Gmelin, E Huang, Q Lynn, JW AF Kasper, NV Troyanchuk, IO Khalyavin, DD Hamad, N Haupt, L Frobel, P Barner, K Gmelin, E Huang, Q Lynn, JW TI Effect of oxygen content and oxygen vacancy ordering on the properties of TbBaCo2O6-delta perovskites SO PHYSICA STATUS SOLIDI B-BASIC RESEARCH LA English DT Article; Proceedings Paper CT International Conference on Solid State Spectroscopy - (ICSSS) CY SEP 05-07, 1999 CL SCHWABISCH-GMUND, GERMANY SP Max Planck Gesellschaft, Munchen, Max Planck Inst Festkorper Forschung, Stuttgart ID GD AB Using IR-spectroscopy, heat capacity experiments, neutron and X-ray diffraction, as well as magnetization and resistivity measurements, TbBaCo2O6-delta samples with different oxygen content and different thermal history are studied. It is shown that the structural, magnetic and electrical properties are strongly sensitive to oxygen content and oxygen vacancy ordering. We submit that the first order semiconductor-to-metal phase transition at 340 to 345 K in this compound is accompanied by oxygen vacancy ordering and short-range magnetic ordering, and only at 285 K spontaneous long-range ferrimagnetic ordering occurs. C1 Univ Gottingen, Inst Phys 4, D-37073 Gottingen, Germany. Inst Solid State Phys & Semicond, Minsk 220072, Byelarus. Max Planck Inst Festkorperforsch, D-70569 Stuttgart, Germany. Natl Inst Stand & Technol, Gaithersburg, MD USA. RP Barner, K (reprint author), Univ Gottingen, Inst Phys 4, Bunsenstr 11-15, D-37073 Gottingen, Germany. RI Khalyavin, Dmitry/E-4335-2017 OI Khalyavin, Dmitry/0000-0002-6724-7695 NR 9 TC 12 Z9 12 U1 0 U2 4 PU WILEY-V C H VERLAG GMBH PI BERLIN PA MUHLENSTRASSE 33-34, D-13187 BERLIN, GERMANY SN 0370-1972 J9 PHYS STATUS SOLIDI B JI Phys. Status Solidi B-Basic Res. PD SEP PY 1999 VL 215 IS 1 BP 697 EP 701 DI 10.1002/(SICI)1521-3951(199909)215:1<697::AID-PSSB697>3.0.CO;2-H PG 5 WC Physics, Condensed Matter SC Physics GA 234ME UT WOS:000082487800113 ER PT J AU FitzGerald, SA Yildirim, T Santodonato, LJ Neumann, DA Copley, JRD Rush, JJ Trouw, F AF FitzGerald, SA Yildirim, T Santodonato, LJ Neumann, DA Copley, JRD Rush, JJ Trouw, F TI Quantum dynamics of interstitial H-2 in solid C-60 SO PHYSICAL REVIEW B LA English DT Article ID INTERCALATION; CO; NE AB We present a neutron-scattering study of the quantum dynamics of molecular hydrogen trapped inside solid C-60 The loading isotherm is shown to deviate significantly from a standard Langmuir response and follows instead an exponential form, increasing from 40% filling at 130 atm to 90% at 700 atm. Diffraction data confirm that the adsorbed molecules are randomly oriented and sit exclusively at the octahedral site. Inelastic neutron scattering clearly shows the ortho to para conversion of the interstitial hydrogen, which occurs via a transition from the J = 1 to J = 0 rotational levels. The level scheme shows relatively minor deviations (on the order of a few percent) from the free rotor model with the splitting in the excited level being the same, 0.7 meV, for both H-2 and D-2. In contrast the shift in the overall level, which is shown to depend critically upon zero-point motion is almost three times greater for H-2 than D-2. We also identify the translational modes of the trapped molecules which occur at a much higher energy than would be classically predicted and have an isotopic shift on the order of root 2.2. Quantum-mechanical model calculations within the self-consistent harmonic approximation indicate that zero-point motion of H-2 molecules in the ground state play the central role in understanding the experimental results, and in particular the high energy of the translational modes and the magnitude of their isotopic shift. [S0163-1829(99)03133-1]. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Oberlin Coll, Dept Phys, Oberlin, OH 44074 USA. Argonne Natl Lab, Intense Pulsed Neutron Source, Argonne, IL 60439 USA. RP FitzGerald, SA (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RI yildirim, taner/A-1290-2009; OI Santodonato, Louis/0000-0002-4600-685X NR 18 TC 70 Z9 71 U1 0 U2 6 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD SEP 1 PY 1999 VL 60 IS 9 BP 6439 EP 6451 DI 10.1103/PhysRevB.60.6439 PG 13 WC Physics, Condensed Matter SC Physics GA 235YA UT WOS:000082570400056 ER PT J AU Skripov, AV Cook, JC Karmonik, C Kozhanov, VN AF Skripov, AV Cook, JC Karmonik, C Kozhanov, VN TI Hydrogen motion in C15-type ZrMo2Hx: Quasielastic neutron scattering and nuclear-magnetic-resonance studies SO PHYSICAL REVIEW B LA English DT Article ID COMPOUNDS ZRCR2HX; SPIN RELAXATION; H(D) ATOMS; DIFFUSION; HYDRIDES; MOBILITY AB In order to determine the parameters of H motion in the cubic (C15-type) Laves phase ZrMo2, we have performed quasielastic neutron scattering measurements and nuclear-magnetic-resonance measurements of the proton spin-lattice relaxation rate on ZrMo2Hx(0.3 less than or equal to x less than or equal to 1.0) in the temperature range 10-430 K. The diffusive motion of hydrogen in this system can be described in terms of two jump processes: the fast localized H motion within the hexagons formed by interstitial g (Zr2Mo2) sites and the slower hopping from one hexagon to the other. The hopping rate tau(l)(-1) of the faster process is found to be of the order of 10(10) s(-1) at 300 K. The characteristic frequency tau(d)(-1) Of the slower process at the same temperature is about 6 x 10(7) s(-1). Comparison of the motional parameters of hydrogen in ZrMo2Hx with those in the related C15-type systems TaV2Hx and ZrCr2Hx shows that the value of tau(d)/tau(l) for ZrMo2Hx lies between the corresponding values for TaV2Hx and ZrCr2Hx. This is consistent with the changes in the ratio of g-g distances r(1) (within the hexagons) and r(2) (between different hexagons). [S0163-1829(99)00433-6]. C1 Russian Acad Sci, Urals Branch, Inst Met Phys, Ekaterinburg 620219, Russia. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Skripov, AV (reprint author), Russian Acad Sci, Urals Branch, Inst Met Phys, Ekaterinburg 620219, Russia. RI Karmonik, Christof/B-6150-2009; Skripov, Alexander/K-4525-2013 OI Skripov, Alexander/0000-0002-0610-5538 NR 21 TC 21 Z9 21 U1 0 U2 4 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD SEP 1 PY 1999 VL 60 IS 10 BP 7238 EP 7244 DI 10.1103/PhysRevB.60.7238 PG 7 WC Physics, Condensed Matter SC Physics GA 239PD UT WOS:000082777800042 ER PT J AU Donati, C Glotzer, SC Poole, PH Kob, W Plimpton, SJ AF Donati, C Glotzer, SC Poole, PH Kob, W Plimpton, SJ TI Spatial correlations of mobility and immobility in a glass-forming Lennard-Jones liquid SO PHYSICAL REVIEW E LA English DT Article ID MOLECULAR-DYNAMICS SIMULATION; HIGHLY SUPERCOOLED LIQUIDS; LONG-LIVED STRUCTURES; TRANSITION TEMPERATURE; COOPERATIVE MOTION; BETA-RELAXATION; POLYMER SURFACE; O-TERPHENYL; T-G; DIFFUSION AB Using extensive molecular dynamics simulations of an equilibrium, glass-forming Lennard-Jones mixture, we characterize in detail the local atomic motions. We show that spatial correlations exist among particles undergoing extremely large ("mobile") or extremely small:("immobile") displacements over a suitably chosen time interval. The immobile particles form the cores of relatively compact clusters, while the mobile particles move cooperatively and form quasi-one-dimensional stringlike clusters. The strength and length scale of the correlations between mobile particles are found to grow strongly with decreasing temperature, and the mean cluster size appears to diverge near the mode-coupling critical; temperature. We show that these correlations in the particle displacements are related to equilibrium fluctuations in the local potential energy and local composition. [S1063-651X(99)06309-6]. C1 NIST, Div Polymers, Gaithersburg, MD 20899 USA. NIST, Ctr Theoret & Computat Mat Sci, Gaithersburg, MD 20899 USA. Univ Western Ontario, Dept Appl Math, London, ON N6A 5B7, Canada. Univ Mainz, Inst Phys, D-55099 Mainz, Germany. Sandia Natl Labs, Parallel Computat Sci Dept, Albuquerque, NM 87185 USA. RP Glotzer, SC (reprint author), NIST, Div Polymers, Gaithersburg, MD 20899 USA. RI Poole, Peter/C-7943-2009; Donati, Claudio/J-5180-2012; Kob, Walter/L-7010-2013; OI Poole, Peter/0000-0001-5985-0585; Kob, Walter/0000-0001-7405-2178; Donati, Claudio/0000-0001-8688-1651 NR 70 TC 359 Z9 361 U1 1 U2 48 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1063-651X J9 PHYS REV E JI Phys. Rev. E PD SEP PY 1999 VL 60 IS 3 BP 3107 EP 3119 DI 10.1103/PhysRevE.60.3107 PG 13 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA 239PH UT WOS:000082778200087 PM 11970118 ER PT J AU Dennis, RE AF Dennis, RE TI Dual-career couples can trouble students SO PHYSICS TODAY LA English DT Letter C1 Natl Ocean & Atmospher Adm, Camp Springs, MD 20748 USA. RP Dennis, RE (reprint author), Natl Ocean & Atmospher Adm, Camp Springs, MD 20748 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0031-9228 J9 PHYS TODAY JI Phys. Today PD SEP PY 1999 VL 52 IS 9 BP 78 EP 78 DI 10.1063/1.882832 PG 1 WC Physics, Multidisciplinary SC Physics GA 231PX UT WOS:000082319900024 ER PT J AU Thomas, CL Bur, AJ AF Thomas, CL Bur, AJ TI In-situ monitoring of product shrinkage during injection molding using an optical sensor SO POLYMER ENGINEERING AND SCIENCE LA English DT Article ID POLYMER AB We have used an optical fiber sensor for in-situ monitoring of product shrinkage during injection molding. The sensor, consisting of a bundle of optical fibers with a sapphire window at its end, is positioned in the ejector pin channel of the mold so that the sapphire window sits flush with the inside wall of the mold cavity. The optical view with this sensor is through the thickness (3.175 mm) of the molded product. The fiber bundle is divided into light excitation fibers and light collection fibers. Light from a helium neon laser is transmitted to the resin via the excitation fibers and the detected response is light that reflects from any interface at which there is a difference of index of refraction. When the molded product shrinks, it separates from the wall and sapphire window, and establishes the geometry of a Fabry-Perot interferometer. During the molding of polystyrene, polypropylene and polyethylene, we observed optical interference hinges that were generated by the movement of the molded product away from the mold wall and window. By counting fringes, a measurement of shrinkage was made. Sensor behavior is described by a model that takes into account the reflection coefficient at each surface, the change in index of refraction of the resin and the coherence of the excitation light. The model has been used to describe asymmetric product shrinkage. C1 Univ Utah, Dept Mech Engn, Salt Lake City, UT 84112 USA. Natl Inst Stand & Technol, Div Polymers, Gaithersburg, MD 20899 USA. RP Thomas, CL (reprint author), Univ Utah, Dept Mech Engn, Salt Lake City, UT 84112 USA. NR 13 TC 20 Z9 20 U1 0 U2 1 PU SOC PLASTICS ENG INC PI BROOKFIELD PA 14 FAIRFIELD DR, BROOKFIELD, CT 06804-0403 USA SN 0032-3888 J9 POLYM ENG SCI JI Polym. Eng. Sci. PD SEP PY 1999 VL 39 IS 9 BP 1619 EP 1627 DI 10.1002/pen.11556 PG 9 WC Engineering, Chemical; Polymer Science SC Engineering; Polymer Science GA 241KQ UT WOS:000082882600006 ER PT J AU Wong-Ng, W Kaduk, JA Young, RA Jiang, F Swartzendruber, LJ Brown, HJ AF Wong-Ng, W Kaduk, JA Young, RA Jiang, F Swartzendruber, LJ Brown, HJ TI Investigation of (Sr4-delta Ca delta)PtO6 using X-ray Rietveld refinement SO POWDER DIFFRACTION LA English DT Article ID TERNARY PLATINUM OXIDES; BOND-VALENCE PARAMETERS; CU-O SYSTEM; MAGNETIC-PROPERTIES; CRYSTAL-STRUCTURE AB The structures of the solid solution series (Sr4-deltaCadelta)PtO6, with delta = 0, 0.85(1), 2, and 3, have been investigated using the Rietveld refinement technique with laboratory X-ray powder diffraction data. A complete solid solution between Sr and Ca was confirmed to exist. These compounds crystallize in the rhombohedral space group R (3) over bar c. The cell parameters of the series range from a of 9.4780(3) to 9.7477(1) Angstrom, and c from 11.3301(4) to 11.8791(1)Angstrom for delta from 3 to 0, respectively. The structure consists of chains of alternating trigonal prismatic (Sr, Ca)O-6 and octahedral PtO6 units running parallel to the c axis. These chains are connected to each other via a second type of (Sr, Ca) ions, which are surrounded by eight oxygens, in a distorted square antiprismatic geometry. As Ca replaced Sr in Sr4PtO6, it was found to substitute preferentially in the smaller octahedral (Sr, Ca)1 site (6a) rather than at the eight-coordinate (Sr, Ca)2 site (18e). There appears to be an anomaly of cell parameters a and c at the compound Sr3.15Ca0.85PtO6 Their dependence on Ca content changes at delta approximate to 1.00, where the Ca has fully replaced Sr in the 6a site. The substitution of Sr by Ca reduced the average (Sr, Ca)1-0 length from 2.411 to 2.311 Angstrom and (Sr, Ca)2-0 from 2.659 to 2.570 Angstrom as the composition varied from Sr4PtO6 to SrCa3PtO6. Reference X-ray powder diffraction patterns were prepared from the Rietveld refinement:results for these members of the solid solution series. Magnetic susceptibility measurements of three of the samples (delta = 0, 0.85, 2) show electronic transitions at low temperatures. (C) 1999 International Centre for Diffraction Data. [S0885-7156(98)00304-2]. C1 NIST, Div Ceram, Gaithersburg, MD 20899 USA. Amoco Corp, Naperville, IL 60566 USA. Georgia Inst Technol, Sch Phys, Atlanta, GA 30332 USA. Univ Maryland, Dept Geol, College Pk, MD 20742 USA. NIST, Div Met, Gaithersburg, MD 20899 USA. RP Wong-Ng, W (reprint author), NIST, Div Ceram, Gaithersburg, MD 20899 USA. NR 24 TC 3 Z9 3 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0885-7156 J9 POWDER DIFFR JI Powder Diffr. PD SEP PY 1999 VL 14 IS 3 BP 181 EP 189 PG 9 WC Materials Science, Characterization & Testing SC Materials Science GA 235KK UT WOS:000082540700004 ER PT J AU O'Brien, TC Fadem, TJ AF O'Brien, TC Fadem, TJ TI Identifying new business opportunities SO RESEARCH-TECHNOLOGY MANAGEMENT LA English DT Article AB In times of rapid market, business and technological change, large science-based companies must create their own futures by developing profitable new growth as soon as a market appears viable. Visualization of these new business possibilities, however, depends on foresight. This requires the company to develop processes for continually applying market and technical knowledge in a constant search for opportunities that intersect with its capabilities. DuPont's recent experiences in developing new business ventures have made extensive use of this approach. The key ingredient has been the use of multidisciplined, multi-experience-based new business venture teams. C1 DuPont Corp New Business Dev, Wilmington, DE USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP O'Brien, TC (reprint author), DuPont Corp New Business Dev, Wilmington, DE USA. NR 13 TC 0 Z9 0 U1 1 U2 4 PU INDUSTRIAL RESEARCH INST INC PI WASHINGTON PA 1550 M ST., NW, WASHINGTON, DC 20005 USA SN 0895-6308 J9 RES TECHNOL MANAGE JI Res.-Technol. Manage. PD SEP-OCT PY 1999 VL 42 IS 5 BP 15 EP 19 PG 5 WC Business; Engineering, Industrial; Management SC Business & Economics; Engineering GA 231RD UT WOS:000082323100005 ER PT J AU Germer, TA Asmail, CC AF Germer, TA Asmail, CC TI Goniometric optical scatter instrument for out-of-plane ellipsometry measurements SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article ID POLARIZED-LIGHT-SCATTERING; STOKES PARAMETERS; ROUGH SURFACES; SPECKLE FIELDS; 1ST-ORDER STATISTICS; MUELLER MATRIX AB A goniometric optical scatter instrument has been developed at the National Institute of Standards and Technology which can readily perform measurements of optical scatter and its associated polarization in directions out of the plane of incidence. In this article the coordinate transformations that are required to operate such a goniometer with respect to sample-specific coordinates are described. We present new methods for measuring the 3x3 nonhanded Mueller matrix elements using dual rotating half-wave retarders, and present a subset of the Mueller matrix, referred to as the bidirectional ellipsometric parameters which have been shown to simplify the interpretation of the data. The results of out-of-plane Mueller matrix and bidirectional ellipsometric measurements from a titanium nitride layer on silicon are presented. [S0034-6748(99)02309-6]. C1 Natl Inst Stand & Technol, Opt Technol Div, Gaithersburg, MD 20899 USA. RP Germer, TA (reprint author), Natl Inst Stand & Technol, Opt Technol Div, Gaithersburg, MD 20899 USA. NR 30 TC 83 Z9 83 U1 0 U2 5 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD SEP PY 1999 VL 70 IS 9 BP 3688 EP 3695 DI 10.1063/1.1149950 PG 8 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 231CK UT WOS:000082289200032 ER PT J AU Qiu, SG Zhou, F Crandall, PE AF Qiu, SG Zhou, F Crandall, PE TI Discrete Gabor transforms with complexity O(NlogN) SO SIGNAL PROCESSING LA English DT Article DE discrete Gabor transforms (DGT); Gabor analysis; Gabor synthesis; fast Fourier transform ID FREQUENCY; EXPANSION AB We develop fast computations of discrete Gabor transforms. We present algorithms for computations of both Gabor analysis and Gabor synthesis via the fast Fourier transform. The algorithms are performed with complexity O(N log N). In addition, we propose an algorithm for computing the dual Gabor wavelets with complexity less than O(N log N). (C) 1999 Elsevier Science B.V. All rights reserved. C1 Ambient Technol Inc, NCDC, Raleigh, NC 27615 USA. RP Ambient Technol Inc, NCDC, 110 Horizon Dr, Raleigh, NC 27615 USA. EM sigang@rsa.cirrus.com NR 21 TC 23 Z9 25 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0165-1684 EI 1879-2677 J9 SIGNAL PROCESS JI Signal Process. PD SEP PY 1999 VL 77 IS 2 BP 159 EP 170 DI 10.1016/S0165-1684(99)00030-4 PG 12 WC Engineering, Electrical & Electronic SC Engineering GA 227VW UT WOS:000082101500003 ER PT J AU Berejikian, BA Tezak, EP Schroder, SL Flagg, TA Knudsen, CM AF Berejikian, BA Tezak, EP Schroder, SL Flagg, TA Knudsen, CM TI Competitive differences between newly emerged offspring of captive-reared and wild coho salmon SO TRANSACTIONS OF THE AMERICAN FISHERIES SOCIETY LA English DT Article ID AGONISTIC BEHAVIOR; ONCORHYNCHUS-KISUTCH; ATLANTIC SALMON; BODY SIZE; DOMINANCE; HATCHERY; GROWTH; GAIRDNERI; POPULATIONS; EXPERIENCE AB We investigated competition among newly emerged fry from captive-reared and wild female coho salmon Oncorhynchus kisutch by conducting dominance challenges and growth and survival experiments in laboratory stream channels. Newly emerged fry from captive-reared females won a significant majority (72.7%) of dyadic dominance challenges against fry from wild females. In a growth and survival experiment conducted from emergence to 30 d postemergence. fewer captive brood fry died of apparent starvation when food was limited than wild fry. further suggesting a competitive advantage for the captive brood fry. All fry used in the study were paternal half-sibs, so observed differences between captive brood and wild fry were attributed to the maternal parent. We hypothesize that fry coloration resulting from differences in egg color between wild and captive-reared females may have influenced the observed competitive asymmetries. If so, such differences might be ameliorated by changes in husbandry practices such as providing more natural diets. C1 NW Fisheries Sci Ctr, Natl Marine Fisheries Serv, Manchester Marine Expt Stn, Manchester, WA 98353 USA. Washington Dept Fish & Wildlife, Olympia, WA 98501 USA. RP Berejikian, BA (reprint author), NW Fisheries Sci Ctr, Natl Marine Fisheries Serv, Manchester Marine Expt Stn, POB 130, Manchester, WA 98353 USA. EM barry.berejikian@noaa.gov NR 33 TC 23 Z9 23 U1 1 U2 8 PU TAYLOR & FRANCIS INC PI PHILADELPHIA PA 325 CHESTNUT ST, SUITE 800, PHILADELPHIA, PA 19106 USA SN 0002-8487 J9 T AM FISH SOC JI Trans. Am. Fish. Soc. PD SEP PY 1999 VL 128 IS 5 BP 832 EP 839 DI 10.1577/1548-8659(1999)128<0832:CDBNEO>2.0.CO;2 PG 8 WC Fisheries SC Fisheries GA 351XC UT WOS:000089183900005 ER PT J AU Murphy, ML Heintz, RA Short, JW Larsen, ML Rice, SD AF Murphy, ML Heintz, RA Short, JW Larsen, ML Rice, SD TI Recovery of pink salmon spawning areas after the Exxon Valdez oil spill SO TRANSACTIONS OF THE AMERICAN FISHERIES SOCIETY LA English DT Article ID PRINCE-WILLIAM-SOUND; AROMATIC-COMPOUNDS; SEDIMENTS; HYDROCARBONS; ENVIRONMENT; INDUCTION; TISSUES; DAMAGE; ALASKA AB Up to 70% of wild pink salmon Oncorhynchus gorbuscha in Prince William Sound, Alaska, spawn in intertidal stream areas, many of which were contaminated by the 1989 Exxon Valdez oil spill. To assess recovery of salmon habitat after the spill, we analyzed sediment samples from stream deltas throughout Prince William Sound from 1989 to 1991 and 1995. In 1989, petroleum hydrocarbon concentration at 172 stream deltas (1-8 samples each) was bimodally distributed: 85 deltas had no detectable petroleum hydrocarbons (detection limit, 2 mu g/g), whereas 87 deltas had a concentration of 2-90,000 mu g/g. In 1995, petroleum hydrocarbons were still detected at eight of nine oiled streams that we resampled, with mean concentration up to 242 mu g/g. The polynuclear aromatic hydrocarbon (PAH) fraction was also analyzed in 1995 to determine its origin, state of weathering, and toxic potential of the residual oil. The PAH fraction consisted mostly of the more toxic compounds with high molecular weight (e.g., phenanthrenes and chrysenes), and PAH composition was consistent with weathered Exxon Valdez oil. Total PAH concentration in 1995 averaged 0-1,300 ng/g, which was below the minimum sediment concentration (3,800 ng/g) shown to reduce salmon embryo survival in the laboratory. Interpolation between 1989 and 1995 indicated that residual PAH concentration exceeded 3,800 ng/g at some stream deltas through 1993, but all streams were below this level by 1994. We conclude that tidal leaching of PAH from weathered oil into incubation substrate could explain persistent elevated embryo mortality observed in pink salmon through 1993, and that spawning habitat had recovered to below lethal threshold by 1994. C1 NOAA, Auke Bay Lab, Alaska Fisheries Sci Ctr, Natl Marine Fisheries Serv, Juneau, AK 99801 USA. RP Murphy, ML (reprint author), NOAA, Auke Bay Lab, Alaska Fisheries Sci Ctr, Natl Marine Fisheries Serv, 11305 Glacier Highway, Juneau, AK 99801 USA. EM mike.murphy@noaa.gov NR 27 TC 16 Z9 17 U1 4 U2 20 PU TAYLOR & FRANCIS INC PI PHILADELPHIA PA 325 CHESTNUT ST, SUITE 800, PHILADELPHIA, PA 19106 USA SN 0002-8487 J9 T AM FISH SOC JI Trans. Am. Fish. Soc. PD SEP PY 1999 VL 128 IS 5 BP 909 EP 918 DI 10.1577/1548-8659(1999)128<0909:ROPSSA>2.0.CO;2 PG 10 WC Fisheries SC Fisheries GA 351XC UT WOS:000089183900013 ER PT J AU Quinn, TP Smith, C McCowan, CN Blachowiak, E Madigan, RB AF Quinn, TP Smith, C McCowan, CN Blachowiak, E Madigan, RB TI Arc sensing for defects in constant-voltage gas metal arc welding SO WELDING JOURNAL LA English DT Article DE algorithm; constant voltage; defects; GMAW; monitoring; process control; sensors AB A method for detecting flaws in automatic, constant-voltage gas metal are welding using the process current and voltage signals was developed. Seven algorithms process the current and voltage signals to give quality parameters. A defect-detection algorithm processes the quality parameters and flags welds that are different from a baseline. The baseline is constructed from the recorded quality parameters of previously made, defect-free welds. Two series of tests were conducted to test the sensitivity of the algorithms for defects and to test the entire sensor system in production. In the first series, on a 3-mm lap joint, the algorithms detected a lack of shielding gas, oily parts and melt-through from inadequate part cross section, but could not detect off-joint welding. The algorithms showed a mixed sensitivity to melt-through from large root openings. In production tests, 520 welds were monitored. The defect detection algorithm was tuned on data from the first 82 welds. The sensor flagged five of the six defects monitored and did not flag any defect-free welds. The defect not detected was a small pore, < 3 mm diameter. C1 Natl Inst Stand & Technol, Boulder, CO USA. Tower Automot, Milwaukee, WI USA. AO Smith Corp, Milwaukee, WI USA. Arc Log, Breckenridge, CO 80424 USA. RP Quinn, TP (reprint author), Natl Inst Stand & Technol, 325 Broadway, Boulder, CO USA. NR 14 TC 12 Z9 15 U1 0 U2 4 PU AMER WELDING SOC PI MIAMI PA PO BOX 351040, MIAMI, FL 33135 USA SN 0043-2296 J9 WELD J JI Weld. J. PD SEP PY 1999 VL 78 IS 9 BP 322S EP 328S PG 7 WC Metallurgy & Metallurgical Engineering SC Metallurgy & Metallurgical Engineering GA 231TK UT WOS:000082326100026 ER PT J AU You, HJ Swanson, RL Harrington, C Corbett, AH Jinks-Robertson, S Senturker, S Wallace, SS Boiteux, S Dizdaroglu, M Doetsch, PW AF You, HJ Swanson, RL Harrington, C Corbett, AH Jinks-Robertson, S Senturker, S Wallace, SS Boiteux, S Dizdaroglu, M Doetsch, PW TI Saccharomyces cerevisiae Ntg1p and Ntg2p: Broad specificity N-glycosylases for the repair of oxidative DNA damage in the nucleus and mitochondria SO BIOCHEMISTRY LA English DT Article ID COLI ENDONUCLEASE-III; ESCHERICHIA-COLI; MOLECULAR-CLONING; HUMAN HOMOLOG; YEAST; GENE; PROTEIN; EXPRESSION; SUPEROXIDE; PURIFICATION AB Saccharomyces cerevisiae possesses two functional homologues (Ntg1p and Ntg2p) of the Escherichia coli endonuclease III protein, a DNA base excision repair N-glycosylase with a broad substrate specificity directed primarily against oxidatively damaged pyrimidines. The substrate specificites of Ntg1p and Ntg2p are similar but not identical, and differences in their amino acid sequences as well as inducibility by DNA damaging agents suggest that the two proteins may have different biological roles and subcellular locations. Experiments performed on oligonucleotides containing a variety of oxidative base damages indicated that dihydrothymine, urea, and uracil glycol are substrates for Ntg1p and Ntg2p, although dihydrothymine was a poor substrate for Ntg2p. Vectors encoding Ntg1p-green fluorescent protein (GFP) and Ntg2p-GFP fusions under the control of their respective endogenous promoters were utilized to observe the subcellular targeting of Ntg1p and Ntg2p in S, cerevisiae. Fluorescence microscopy of pNTG1-GFP and pNTG2-GFP transformants revealed that Ntg1p localizes primarily to the mitochondria with some nuclear localization, whereas Ntg2p localizes exclusively to the nucleus. In addition, the subcellular location of Ntg1p and Ntg2p confers differential sensitivities to the alkylating agent MMS, These results expand the known substrate specifities of Ntg1p and Ntg2p, indicating that their base damage recognition ranges show distinct differences and that these proteins mediate different roles in the repair of DNA base damage in the nucleus and mitochondria of yeast. C1 Emory Univ, Sch Med, Dept Biochem, Atlanta, GA 30322 USA. Emory Univ, Sch Med, Dept Biol, Atlanta, GA 30322 USA. Emory Univ, Sch Med, Dept Radiat Oncol, Div Canc Biol, Atlanta, GA 30322 USA. Univ Vermont, Markey Ctr Mol Genet, Dept Microbiol & Mol Genet, Burlington, VT 05405 USA. CEA, CNRS, UMR217, Dept Radiobiol & Radiopathol, F-92265 Fontenay Aux Roses, France. NIST, Chem Sci & Technol Lab, Gaithersburg, MD 20899 USA. RP Emory Univ, Sch Med, Dept Biochem, Atlanta, GA 30322 USA. EM medpwd@emory.edu FU NCI NIH HHS [CA 73041, CA 33657]; NIGMS NIH HHS [GM 38464] NR 50 TC 98 Z9 103 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0006-2960 J9 BIOCHEMISTRY-US JI Biochemistry PD AUG 31 PY 1999 VL 38 IS 35 BP 11298 EP 11306 DI 10.1021/bi991121i PG 9 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 235AG UT WOS:000082516100009 PM 10471279 ER PT J AU Levin, I Leapman, RD Kaiser, DL van Buskirk, PC Bilodeau, S Carl, R AF Levin, I Leapman, RD Kaiser, DL van Buskirk, PC Bilodeau, S Carl, R TI Accommodation of excess Ti in a (Ba, Sr)TiO3 thin film with 53.4% Ti grown on Pt/SiO2/Si by metalorganic chemical-vapor deposition SO APPLIED PHYSICS LETTERS LA English DT Article ID DIELECTRIC-PROPERTIES; (BA,SR)TIO3 AB The microstructure and chemistry of a Ti-rich (Ba, Sr)TiO3 film with 53.4% Ti deposited on a Pt/SiO2/Si substrate by metallorganic chemical-vapor deposition was studied using high-resolution transmission electron microscopy and elemental mapping in electron energy-loss spectroscopy. We established that the Ti/Ba ratio at all the grain boundaries in this film is significantly higher than that in the grain interiors. Structural images revealed the presence of disordered amorphous-like regions at some of the grain boundaries and triple junctions; these regions were tentatively identified as those having the highest Ti/Ba ratio in the chemical maps. Analysis of the electron energy-loss near-edge structure for the O-K edge indicated an increased titanium-to-oxygen coordination at the grain boundaries. No second phase was detected at the (Ba, Sr)TiO3/Pt interface. (C) 1999 American Institute of Physics. [S0003-6951(99)01735-0]. C1 Natl Inst Stand & Technol, Div Ceram, Gaithersburg, MD 20899 USA. NIH, ORS, Bethesda, MD 20892 USA. Appl Technol Mat Inc, Danbury, CT 06810 USA. RP Levin, I (reprint author), Natl Inst Stand & Technol, Div Ceram, Gaithersburg, MD 20899 USA. RI Levin, Igor/F-8588-2010 NR 13 TC 19 Z9 21 U1 0 U2 4 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD AUG 30 PY 1999 VL 75 IS 9 BP 1299 EP 1301 DI 10.1063/1.124674 PG 3 WC Physics, Applied SC Physics GA 228BV UT WOS:000082117000038 ER PT J AU Thompson, PE Hobart, KD Twigg, ME Jernigan, GG Dillon, TE Rommel, SL Berger, PR Simons, DS Chi, PH Lake, R Seabaugh, AC AF Thompson, PE Hobart, KD Twigg, ME Jernigan, GG Dillon, TE Rommel, SL Berger, PR Simons, DS Chi, PH Lake, R Seabaugh, AC TI Si resonant interband tunnel diodes grown by low-temperature molecular-beam epitaxy SO APPLIED PHYSICS LETTERS LA English DT Article ID ROOM-TEMPERATURE; SILICON AB Si resonant interband tunnel diodes that demonstrate negative differential resistance at room temperature, with peak-to-valley current ratios greater than 2, are presented. The structures were grown using low-temperature (320 degrees C) molecular-beam epitaxy followed by a postgrowth anneal. After a 650 degrees C, 1 min rapid thermal anneal, the average peak-to-valley current ratio was 2.05 for a set of seven adjacent diodes. The atomic distribution profiles of the as-grown and annealed structures were obtained by secondary ion mass spectrometry. Based on these measurements, the band structure was modeled and current-voltage trends were predicted. These diodes are compatible with transistor integration. (C) 1999 American Institute of Physics. [S0003-6951(99)01935-X]. C1 USN, Res Lab, Washington, DC 20375 USA. Univ Delaware, Dept Elect & Comp Engn, Newark, DE 19716 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Raytheon Syst Co, Appl Res Lab, Dallas, TX 75243 USA. RP Thompson, PE (reprint author), USN, Res Lab, Washington, DC 20375 USA. RI Seabaugh, Alan/I-4473-2012; Rommel, Sean/F-9654-2013; Berger, Paul/I-4063-2014 OI Seabaugh, Alan/0000-0001-6907-4129; Rommel, Sean/0000-0001-5996-0813; Berger, Paul/0000-0002-2656-2349 NR 19 TC 25 Z9 25 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD AUG 30 PY 1999 VL 75 IS 9 BP 1308 EP 1310 DI 10.1063/1.124677 PG 3 WC Physics, Applied SC Physics GA 228BV UT WOS:000082117000041 ER PT J AU Murton, BJ Redbourn, LJ German, CR Baker, ET AF Murton, BJ Redbourn, LJ German, CR Baker, ET TI Sources and fluxes of hydrothermal heat, chemicals and biology within a segment of the Mid-Atlantic Ridge SO EARTH AND PLANETARY SCIENCE LETTERS LA English DT Article DE hydrothermal conditions; heat flux; geochemistry; biology ID DE-FUCA-RIDGE; VENT FIELD; OCEAN; JUAN; DISTRIBUTIONS; CIRCULATION; CHEMISTRY; DISCRETE; DIFFUSE; PACIFIC AB We have conducted a segment-wide study of the chemical, biological and thermal effects of hydrothermal activity, in a bathymetrically enclosed, 50-km-long segment of the Mid-Atlantic Ridge, at 29 degrees N. Our study involved long-term monitoring of bottom current speeds and temperatures coupled with 'snap-shot' surveys of the concentrations of hydrothermal shrimp, manganese and particulate plumes occupying the water column enclosed by the axial valley. These data are combined with the calculated volume transport rates for the segment and the results compared with the heat and manganese flux from the Broken Spur vent field, located in the center of the segment. Our current meter data show that the basin-like bathymetry acts to restrict and control flow of water. Warm and shallow water, exported from the segment, is replaced by colder and deeper water. Water column profiles showed an increase in temperature of the water within the 'Broken Spur' segment, compared with background stations located outside the ridge axis. The average refresh rate for the water column enclosed by the segment was found to be about 262 days. From these data, we calculate that the segment-wide flux of juvenile shrimp is similar to 20 x 10(6) individuals per year. We show that the flux of manganese (exported at a rate of 5-6 mol/s) is matched by input from high-temperature affluent discharge at the Broken Spur vent field. We also calculate that the minimum average heat flux exported from the segment is about 275 MW. Of this, more than 90% is pervasively dissipated throughout the segment floor by conductively heated sea water, or simple thermal conduction, that carries little or no manganese to the water column. The remaining 10% or less of the heat flux results from localized, manganese-rich, high-temperature hydrothermal venting. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Southampton, Southampton Oceanog Ctr, Southampton SO14 3ZH, Hants, England. NOAA, Pacific Marine Environm Lab, Seattle, WA 98115 USA. RP Murton, BJ (reprint author), Univ Southampton, Southampton Oceanog Ctr, European Way, Southampton SO14 3ZH, Hants, England. NR 40 TC 29 Z9 29 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0012-821X J9 EARTH PLANET SC LETT JI Earth Planet. Sci. Lett. PD AUG 30 PY 1999 VL 171 IS 2 BP 301 EP 317 DI 10.1016/S0012-821X(99)00157-0 PG 17 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 229FU UT WOS:000082183500009 ER PT J AU Waterstrat, RM Shapiro, A Jeremie, A AF Waterstrat, RM Shapiro, A Jeremie, A TI The palladium-zirconium phase diagram SO JOURNAL OF ALLOYS AND COMPOUNDS LA English DT Article DE palladium alloys; zirconium alloys; phase diagrams; crystal structure; intermetallic compounds; martensite structure ID SHAPE-MEMORY ALLOYS; TINI; TRANSFORMATIONS; BEHAVIOR; ZR AB The palladium-zirconium phase diagram has been re-investigated over its entire composition range. The revised diagram includes two intermediate phases, Pd4Zr3 and Pd11Zr9, which did not appear in previous studies. The crystal structures of the new phases resemble the B2-type structure although the atoms are displaced significantly from the cubic lattice sites. The present observations are discussed and compared with similar results from the related systems Ni-Ti and Rh-Zr. Published by Elsevier Science S.A. C1 NIST, Mat Sci & Engn Lab, Gaithersburg, MD 20899 USA. Univ Geneva, Dept Phys Mat Condensee, CH-1211 Geneva 4, Switzerland. RP Waterstrat, RM (reprint author), NIST, Mat Sci & Engn Lab, Gaithersburg, MD 20899 USA. NR 34 TC 22 Z9 23 U1 0 U2 4 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 30 PY 1999 VL 290 IS 1-2 BP 63 EP 70 DI 10.1016/S0925-8388(99)00127-9 PG 8 WC Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Chemistry; Materials Science; Metallurgy & Metallurgical Engineering GA 232QE UT WOS:000082380800014 ER PT J AU Dodd, PJ Edwards, M Clark, CW AF Dodd, PJ Edwards, M Clark, CW TI Two-gas description of dilute Bose-Einstein condensates at finite temperature SO JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS LA English DT Article ID COLLECTIVE EXCITATIONS; ATTRACTIVE INTERACTIONS; MAGNETIC TRAP; ENERGY; ATOMS; CONFIGURATION; INTERFERENCE; FRACTION; NUMBER AB We show that recent treatments of magnetically trapped Bose-Einstein condensates (BECs) at temperature T > 0 fit a simple picture: the condensate wavefunction is that of a T = 0 BEC with the appropriate (depleted) number of condensate atoms N-0, and the surrounding thermal cloud is described by the statistical mechanics of an ideal gas in the combined potentials of the magnetic trap and the cloud-condensate interaction. Even a simple classical description of the cloud reproduces its essential outline, and facilitates easy approximate calculations of BEC properties for T > 0. C1 Univ Maryland, Inst Phys Sci & Technol, College Pk, MD 20742 USA. Georgia So Univ, Dept Phys, Statesboro, GA 30460 USA. Natl Inst Stand & Technol, Div Electron & Opt Phys, Phys Lab, Technol Adm,US Dept Commerce, Gaithersburg, MD 20899 USA. RP Dodd, PJ (reprint author), Univ Maryland, Inst Phys Sci & Technol, College Pk, MD 20742 USA. RI Clark, Charles/A-8594-2009 OI Clark, Charles/0000-0001-8724-9885 NR 46 TC 8 Z9 8 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 28 PY 1999 VL 32 IS 16 BP 4107 EP 4115 DI 10.1088/0953-4075/32/16/310 PG 9 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 234VW UT WOS:000082505900012 ER PT J AU Free, M Robock, A AF Free, M Robock, A TI Global warming in the context of the Little Ice Age SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Review ID SOLAR IRRADIANCE VARIATIONS; GENERAL-CIRCULATION MODEL; SUNS RADIATIVE OUTPUT; CLIMATE-CHANGE; NORTHERN-HEMISPHERE; SURFACE-TEMPERATURE; NATURAL VARIABILITY; PINATUBO ERUPTION; MAUNDER MINIMUM; VOLCANIC DUST AB Understanding the role of volcanic and solar variations in climate change is important not only for understanding the Little Ice Age but also for understanding and predicting the effects of anthropogenic changes in atmospheric composition in the twentieth century and beyond. To evaluate the significance of solar and volcanic effects, we use four solar reconstructions and three volcanic indices as forcings to an energy-balance model and compare the results with temperature reconstructions. Our use of a model representing the climate system response to solar and volcanic forcings distinguishes this from previous direct comparisons of forcings with temperature series for the Little Ice Age. Use of the model allows us to assess the effects of the ocean heat capacity on the evolution of the temperature response, Using a middle-of-the-road model sensitivity of 3 degrees C for doubled CO2, solar forcings of less than 0.5% are too small to account for the cooling of the Little Ice Age. Volcanic forcings, in contrast, give climate responses comparable in amplitude to the changes of the Little Ice Age. A combination of solar and volcanic forcings explains much of the Little Ice Age climate change, but these factors alone cannot explain the warming of the twentieth century. The best simulations of the period since 1850 include anthropogenic, solar, and volcanic forcings. C1 Univ Maryland, Dept Meteorol, College Pk, MD 20742 USA. Rutgers State Univ, Dept Environm Sci, New Brunswick, NJ 08901 USA. RP NOAA, Air Resources Lab, REAR, SSMC3,Room 3151,1315 E W Highway, Silver Spring, MD 20910 USA. EM melissa.free@noaa.gov; robock@envsci.rutgers.edu RI Robock, Alan/B-6385-2016; OI Robock, Alan/0000-0002-6319-5656 NR 106 TC 71 Z9 74 U1 2 U2 20 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 27 PY 1999 VL 104 IS D16 BP 19057 EP 19070 DI 10.1029/1999JD900233 PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 230CY UT WOS:000082235300004 ER PT J AU Avissar, R Lawford, RD AF Avissar, R Lawford, RD TI Special section: GEWEX Continental-Scale International Project (GCIP), Part 2 - Preface SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Editorial Material C1 Rutgers State Univ, Ctr Environm Predict, Piscataway, NJ 08855 USA. Natl Ocean & Atmospher Adm, Off Global Programs, Silver Spring, MD 20910 USA. RP Rutgers State Univ, Ctr Environm Predict, Piscataway, NJ 08855 USA. NR 0 TC 0 Z9 1 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 27 PY 1999 VL 104 IS D16 BP 19275 EP 19277 DI 10.1029/1999JD900369 PG 3 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 230CY UT WOS:000082235300020 ER PT J AU Lawford, RG AF Lawford, RG TI A midterm report on the GEWEX Continental-Scale International Project (GCIP) SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID RIVER BASIN EXPERIMENT; TEMPORAL ANALYSIS; LAND; ENERGY; FLUXES; MODEL AB The GEWEX Continental-Scale International Project (GCIP) is being carried out in the Mississippi River Basin under the auspices of the World Climate Research Program and its Global Energy and Water Cycle Experiment (GEWEX). This paper provides a brief history of GCIP's development and its mission and objectives. The scientific achievements of GCIP are then reviewed against each of these objectives. The paper concludes with a brief discussion of options for the period beyond 2000 after the current phase of the project is completed. C1 NOAA, Off Global Programs, Silver Spring, MD 20910 USA. RP NOAA, Off Global Programs, Suite 1225,1100 Wayne Ave, Silver Spring, MD 20910 USA. NR 26 TC 17 Z9 22 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 27 PY 1999 VL 104 IS D16 BP 19279 EP 19292 DI 10.1029/1999JD900266 PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 230CY UT WOS:000082235300021 ER PT J AU Roads, JO Chen, SC Kanamitsu, M Juang, H AF Roads, JO Chen, SC Kanamitsu, M Juang, H TI Surface water characteristics in NCEP global spectral model and reanalysis SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID RANGE FORECAST MODEL; UNITED-STATES; SOIL-MOISTURE; MONTHLY PRECIPITATION; HYDROLOGIC-CYCLE; LAND-SURFACE; CONTINENTAL WATERSHEDS; FIFE DATA; TEMPERATURE; VARIABILITY AB Characteristics of the National Centers for Environmental Prediction and National Center for Atmospheric Research (NCEP/NCAR) reanalysis surface water budget are compared to the surface water budget characteristics in a long-term simulation with the NCEP global spectral model (GSM) used in the reanalysis. There are many geographic similarities. There are a few differences though, mainly because the reanalysis has a source (artificial) of water from a seasonally varying damping (forcing) term. Because the GSM does not have this (forcing) term, the GSM surface becomes dryer and ultimately has decreased land evaporation and precipitation. Since evaporation variations are strongly related to surface: air and skin temperature variations, this decreased GSM surface water is also associated with increased land temperature. However, the GSM surface water variability is greater because the reanalysis time constant (60 days) used to damp (force) the surface water back to the assumed climatology is shorter than characteristic land surface parameterization hydrologic times, which are of the order of 6 months. In agreement with the decreased surface water variability, the reanalysis evaporation variability is also less than the evaporation variability in the GSM. This artificial time constraint may be a reason that the reanalysis temperature predictability by surface water is less than the demonstrated GSM predictability. C1 Scripps Inst Oceanog, La Jolla, CA 92037 USA. Natl Ctr Environm Predict, Camp Springs, MD USA. RP Scripps Inst Oceanog, Nierenberg Hall,8605 La Jolla Shores Dr, La Jolla, CA 92037 USA. NR 43 TC 55 Z9 59 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 27 PY 1999 VL 104 IS D16 BP 19307 EP 19327 DI 10.1029/98JD01166 PG 21 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 230CY UT WOS:000082235300023 ER PT J AU Berbery, EH Mitchell, KE Benjamin, S Smirnova, T Ritchie, H Hogue, R Radeva, E AF Berbery, EH Mitchell, KE Benjamin, S Smirnova, T Ritchie, H Hogue, R Radeva, E TI Assessment of land-surface energy budgets from regional and global models SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID STEP-MOUNTAIN COORDINATE; MULTISCALE GEM MODEL; ETA-MODEL; WEATHER PREDICTION; NCEP; TEMPERATURE; PERFORMANCE; RADIATION; SCHEME; DESIGN AB The surface energy budgets estimated from the 0- to 12-hour forecasts of three operational model suites and the National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) Reanalysis are analyzed at local to continental scales. The models are (1) the Eta model, (2) the Mesoscale Analysis and Prediction System (MAPS), and (3) the Global Environmental Multiscale (GEM) model. The first two are regional, while the third one is global with a variable grid with a resolution over North America that is equivalent to that of the regional models. This assessment of one summer month (August 1997) and one winter month (January 1998) has the purpose of estimating the reliability of the surface energy budgets within the context of the Global Energy and Water Cycle Experiment (GEWEX) Continental-Scale International Project (GCIP) goals. Satellite estimates were used to evaluate the downward short wave radiation at the surface, while measurements from the southern Great Plains region were used to evaluate the model computed surface energy budget estimates. The results show that the surface short wave radiation biases of the models are widespread and of the order of 25-50 W m(-2) and averaging over larger areas does not help reduce the differences. These biases are compensated by the other long and short wave radiation terms so that the resulting errors in the net radiation are smaller. During August 1997, continental east-west gradients of latent heat flux and Bowen ratio were surprisingly dissimilar among models. Still, the Bowen ratio estimated from the Eta and GEM models was close to observations over the southern Great Plains region, while both the Reanalysis and MAPS had ratios that at least doubled the observed ones. In the case of MAPS a revised latent heat flux formulation was introduced in fall 1997, and, subsequently, for January 1998, estimates were closer to the other models' estimates. However, during January 1998 all models had difficulties reproducing the Bowen ratios from observations. Further, daily time series showed that models' estimates also tended to miss the amplitude of the day-to-day variability. It is conceivable that this may be the result of difficulties in parameterizing the total cloud cover, and, particularly, attenuation by clouds may still be insufficient. C1 Univ Maryland, Dept Meteorol, Cooperat Inst Climate Studies, College Pk, MD 20742 USA. NOAA, Natl Ctr Environm Predict, Environm Modeling Ctr, NWS, Camp Springs, MD 20746 USA. NOAA, Forecast Syst Lab, ERL, Boulder, CO 80303 USA. Environm Canada, Res & Previs Numer, Dorval, PQ H9P 1J3, Canada. RP Univ Maryland, Dept Meteorol, Cooperat Inst Climate Studies, 3411 Comp & Space Sci Bldg, College Pk, MD 20742 USA. EM berbery@atmos.umd.edu RI Berbery, Ernesto/F-4560-2010; Smirnova, Tatiana/D-3350-2015 OI Berbery, Ernesto/0000-0003-2587-3345; NR 37 TC 30 Z9 30 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 27 PY 1999 VL 104 IS D16 BP 19329 EP 19348 DI 10.1029/1999JD900128 PG 20 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 230CY UT WOS:000082235300024 ER PT J AU Yarosh, ES Ropelewski, CF Berbery, EH AF Yarosh, ES Ropelewski, CF Berbery, EH TI Biases of the observed atmospheric water budgets over the central United States SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID LOW-LEVEL JET; MOISTURE BUDGET; ETA-MODEL; HYDROLOGIC-CYCLE; PRECIPITATION; CLIMATOLOGY; REANALYSES; TRANSPORT AB Analysis of the mean annual cycle of the observed water budget based on radiosonde data for the 20 year period 1973 - 1992 reveals a negative bias in the atmospheric estimate of mean moisture flux convergence over the central United States when compared to mean river discharge for the same period. Several possible sources of this bias are examined through the analysis of radiosonde, wind profiler, and river discharge data as well as water budget estimates from NCEP's mesoscale Eta Model. The analysis suggests that 20 years of radiosonde observations are sufficient to get stable mean water vapor flux convergence estimates. The analysis also shows that the bias between averaged vapor flux convergence and river discharge likely does not depend on changes in the locations of upper-air observations or on changes in the radiosondes observational technique. Components of the atmospheric water budget diurnal cycle are estimated from hourly wind profiler data and from 3-hourly Eta Model output. The analyses show that monthly mean atmospheric water budget quantities calculated from twice a day sampling, on average, significantly underestimate magnitudes of these quantities compared to estimates based on hourly or 3-hourly analyses. The magnitude of the underestimation is more than 60% of the difference between mean observed terrestrial and atmospheric components of the hydrological cycle over the central United States, in agreement with earlier studies suggesting that temporal sampling may account for part of this bias. The effect of spatial sampling was evaluated using differences between atmospheric water budget terms from the Eta Model at its full 48 km resolution compared to Eta Model water budget estimates sampled at the radiosonde spatial resolution. These analyses show that the magnitude of the effect of spatial resolution is about 40% of the magnitude of the mean bias between the average moisture flux convergence and river discharge, The combined effect of temporal and spatial undersampling by radiosondes over the central United States is estimated to be 0.44 mm d(-1). This value is within 8% of the estimated mean difference between river discharge and moisture flux convergence for the central United States. C1 NOAA, Natl Ctr Environm Predict, Climate Predict Ctr, Washington, DC 20233 USA. Univ Maryland, Dept Meteorol, Cooperat Inst Climate Studies, College Pk, MD 20742 USA. Columbia Univ, Lamont Doherty Earth Observ, Int Res Inst Climate Predict, Palisades, NY 10964 USA. Res & Data Syst Corp, Greenbelt, MD USA. RP NOAA, NCEP, CPC, 5200 Auth Rd,World Weather Bldg,Room 605, Camp Springs, MD 20746 USA. RI Berbery, Ernesto/F-4560-2010 OI Berbery, Ernesto/0000-0003-2587-3345 NR 36 TC 14 Z9 14 U1 0 U2 1 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 27 PY 1999 VL 104 IS D16 BP 19349 EP 19360 DI 10.1029/1999JD900322 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 230CY UT WOS:000082235300025 ER PT J AU Takle, ES Gutowski, WJ Arritt, RW Pan, ZT Anderson, CJ da Silva, RR Caya, D Chen, SC Giorgi, F Christensen, JH Hong, SY Juang, HMH Katzfey, J Lapenta, WM Laprise, R Liston, GE Lopez, P McGregor, J Pielke, RA Roads, JO AF Takle, ES Gutowski, WJ Arritt, RW Pan, ZT Anderson, CJ da Silva, RR Caya, D Chen, SC Giorgi, F Christensen, JH Hong, SY Juang, HMH Katzfey, J Lapenta, WM Laprise, R Liston, GE Lopez, P McGregor, J Pielke, RA Roads, JO TI Project to Intercompare Regional Climate Simulations (PIRCS): Description and initial results SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID AMERICAN MONSOON SYSTEM; UNITED-STATES; LAND-SURFACE; BOUNDARY-CONDITIONS; LATERAL BOUNDARY; SPECTRAL MODEL; 1988 DROUGHT; FIFE; PRECIPITATION; PARAMETERIZATION AB The first simulation experiment and output archives of the Project to Intercompare Regional Climate Simulations (PIRCS) is described. Initial results from simulations of the summer 1988 drought over the central United States indicate that limited-area models forced by large-scale information at the lateral boundaries reproduce bulk temporal and spatial characteristics of meteorological fields. In particular, the 500 hPa height field time average and temporal variability are generally well simulated by all participating models. Model simulations of precipitation episodes vary depending on the scale of the dynamical forcing. Organized synoptic-scale precipitation systems are simulated deterministically in that precipitation occurs at close to the same time and location as observed (although amounts may vary from observations). Episodes of mesoscale and convective precipitation are represented in a more stochastic sense, with less precise agreement in temporal and spatial patterns. Simulated surface energy fluxes show broad similarity with the First International Satellite Land Surface Climatology Project (ISLSCP) Field Experiment (FIFE) observations in their temporal evolution and time average diurnal cycle. Intermodel differences in midday Bowen ratio tend to be closely associated with precipitation differences. Differences in daily maximum temperatures also are linked to Bowen ratio differences, indicating strong local, surface influence on this field. Although some models have bias with respect to FIFE observations, all tend to reproduce the synoptic variability of observed daily maximum and minimum temperatures. Results also reveal the advantage of an intercomparison in exposing common tendencies of models despite their differences in convective and surface parameterizations and different methods of assimilating lateral boundary conditions. C1 Iowa State Univ, Dept Agron, Ames, IA 50011 USA. Univ Quebec, Montreal, PQ H3C 3P8, Canada. Scripps Inst Oceanog, La Jolla, CA 92037 USA. Abdus Salam Int Ctr Theoret Phys, I-34100 Trieste, Italy. Danish Meteorol Inst, DK-2100 Copenhagen, Denmark. Natl Ctr Environm Predict, Camp Springs, MD 20031 USA. CSIRO, Aspendale, Vic 3195, Australia. Colorado State Univ, Dept Atmospher Sci, Ft Collins, CO 80521 USA. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Iowa State Univ, Dept Agron, 3010 Agron, Ames, IA 50011 USA. EM gstakle@iastate.edu RI Pielke, Roger/A-5015-2009; McGregor, John/C-6646-2012; Pan, Zaitao/D-7846-2012; Hong, Song-You/I-3824-2012; Giorgi, Filippo/C-3169-2013; Christensen, Jens/C-4162-2013; Katzfey, Jack/K-1231-2012; Ramos-da-Silva, Renato/I-4759-2012 OI Christensen, Jens/0000-0002-9908-8203; Katzfey, Jack/0000-0002-0604-8860; NR 46 TC 120 Z9 124 U1 2 U2 9 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 27 PY 1999 VL 104 IS D16 BP 19443 EP 19461 DI 10.1029/1999JD900352 PG 19 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 230CY UT WOS:000082235300033 ER PT J AU Koren, V Schaake, J Mitchell, K Duan, QY Chen, F Baker, JM AF Koren, V Schaake, J Mitchell, K Duan, QY Chen, F Baker, JM TI A parameterization of snowpack and frozen ground intended for NCEP weather and climate models SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID MESOSCALE ETA-MODEL; LAND-SURFACE SCHEME; UNSATURATED SOIL; FROST HEAVE; MOISTURE; COVER; HYDROLOGY; LAYER; TEMPERATURE; CONDUCTIVITY AB Extensions to the land surface scheme (LSS) in the National Centers for Environmental Prediction, regional, coupled, land-atmosphere weather prediction model, known as the mesoscale Eta model, are proposed and tested off-line in uncoupled mode to account for seasonal freezing and thawing of soils and snow-accumulation-ablation processes. An original model assumption that there is no significant heat transfer during redistribution of liquid water was relaxed by including a source/sink term in the heat transfer equation to account for latent heat during phase transitions of soil moisture. The parameterization uses the layer-integrated form of heat and water diffusion equations adopted by the original Eta-LSS. Therefore it simulates the total ice content of each selected soil layer. Infiltration reduction under frozen ground conditions was estimated by probabilistic averaging of spatially variable ice content of the soil profile. Off-line uncoupled tests of the new and original Eta-LSS were performed using experimental data from Rosemount, Minnesota. Simulated soil temperature and unfrozen water content matched observed data reasonably well. Neglecting frozen ground processes leads to significant underestimation/overestimation of soil temperature during soil freezing/thawing periods and underestimates total soil moisture content after extensive periods of soil freezing. C1 NOAA, Natl Weather Serv, Off Hydrol, Silver Spring, MD 20910 USA. Univ Minnesota, USDA ARS, DSWC, Dept Soil Water & Climate, St Paul, MN 55108 USA. NOAA, Natl Ctr Environm Predict, Camp Springs, MD 20746 USA. RP NOAA, Natl Weather Serv, Off Hydrol, 1325 EW Highway, Silver Spring, MD 20910 USA. EM victor.koren@noaa.gov RI Chen, Fei/B-1747-2009; Duan, Qingyun/C-7652-2011 OI Duan, Qingyun/0000-0001-9955-1512 NR 60 TC 258 Z9 281 U1 3 U2 47 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 27 PY 1999 VL 104 IS D16 BP 19569 EP 19585 DI 10.1029/1999JD900232 PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 230CY UT WOS:000082235300042 ER PT J AU Carroll, SS Carroll, TR Poston, RW AF Carroll, SS Carroll, TR Poston, RW TI Spatial modeling and prediction of snow-water equivalent using ground-based, airborne, and satellite snow data SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID INTERNATIONAL PROJECT GCIP AB In this research we modify existing spatial interpolation methodologies so that we can use ground-based and remotely sensed (airborne and satellite) snow data to characterize the spatial distribution of snow-water equivalent (SWE) and obtain optimal gridded SWE predictions in the upper Mississippi River basin. We developed and tested the models using ground-based, airborne, and satellite snow data collected over North and South Dakota, Minnesota, Wisconsin, Iowa, Illinois, and Michigan between March 3 and 6, 1996. Using these data and the spatial models, we obtained optimal gridded predictions of SWE and the associated root mean square prediction errors over a 5 min by 5 min grid covering Minnesota and parts of Wisconsin, North and South Dakota, Iowa, Michigan, and Canada. Because we use an optimal interpolation technique and incorporate satellite areal extent of snow cover data, the predictions are expected to be more accurate than those that would be obtained from interpolation procedures currently used by the National Weather Service. Maps of the gridded snow water equivalent predictions and of the associated error estimates provide a means to investigate the spatial distributions of the predictions and of the associated error estimates. Our research enables hydrologists and others not only to examine these spatial distributions but also to generate optimal gridded predictions of snow-water equivalent that will aid flood forecasting and water resource management efforts. C1 Arizona State Univ, Dept Biol, Tempe, AZ 85287 USA. NOAA, Natl Operat Hydrol Remote Sensing Ctr, Natl Weather Serv, Chanhassen, MN 55317 USA. RP Arizona State Univ, Dept Biol, Box 871501, Tempe, AZ 85287 USA. EM steven.carroll@asu.edu NR 26 TC 19 Z9 19 U1 1 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD AUG 27 PY 1999 VL 104 IS D16 BP 19623 EP 19629 DI 10.1029/1999JD900093 PG 7 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 230CY UT WOS:000082235300046 ER PT J AU Cline, DW Carroll, TR AF Cline, DW Carroll, TR TI Inference of snow cover beneath obscuring clouds using optical remote sensing and a distributed snow energy and mass balance model SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID SCALE AB We describe a new method to infer the presence or absence of snow cover when it is obscured to remote sensing by clouds. The inference is based on the spatial distribution of snow water equivalent (SWE) estimated by a physical snow model. The snow model accounts for surface and internal snowpack energy exchanges and mass exchanges including snow accumulation, sublimation, rainfall, and meltwater outflux. We examine two approaches to using the modeled SWE information to infer snow cover: (1) we directly categorize areas with modeled SWE greater than zero as "snow covered" and areas with zero SWE as "no snow"; (2) we classify the modeled SWE field into a binary map of snow covered/no snow, using maximum likelihood logistic estimation (LR). Here the modeled SWE serves as a semicontinuous independent variable, and the binary dependent variable consists of observed snow cover derived from all available ground observations of snow depth and water equivalent, and from samples of snow cover randomly selected from cloud-free areas of a satellite snow cover product. We demonstrate these methods for a 504,000 km(2) region in the north central United States, over a 4 week period during March and April 1997. The snow model was run hourly on a 4 km grid using data normally available in near real time, including numerical weather analysis products, satellite-derived insolation products, and ground observations of precipitation. We tested two dependent variable data configurations for the LR approach to simulate (1) typical conditions when remotely sensed snow cover observations are available to help develop the logistic model and (2) "worst-case" conditions where only ground-based data are available. Averaged over the study period, all three methods, the direct SWE, the worst-case LR, and the typical LR, yielded comparable results in the range of 78-80% accuracy when compared to satellite-observed snow cover maps. The results of this study demonstrate that a relatively simple, spatially distributed, physically based snow model is capable of providing useful snow cover information in an operational environment. C1 Natl Weather Serv, Natl Operat Hydrol Remote Sensing Ctr, Off Hydrol, Chanhassen, MN 55317 USA. RP Natl Weather Serv, Natl Operat Hydrol Remote Sensing Ctr, Off Hydrol, 1735 Lake Dr W, Chanhassen, MN 55317 USA. EM cline@nohrsc.nws.gov NR 16 TC 20 Z9 22 U1 0 U2 8 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD AUG 27 PY 1999 VL 104 IS D16 BP 19631 EP 19644 DI 10.1029/1999JD900249 PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 230CY UT WOS:000082235300047 ER PT J AU Connelly, BA Braatz, DT Halquist, JB DeWeese, MM Larson, L Ingram, JJ AF Connelly, BA Braatz, DT Halquist, JB DeWeese, MM Larson, L Ingram, JJ TI Advanced hydrologic prediction system SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article AB As our Nation's population and infrastructure grow, natural disasters are becoming a greater threat to our society's stability. In an average year, inland flooding claims 133 lives and resulting property losses exceed $4.0 billion. Last year, 1997, these losses totaled $8.7 billion, Because of this blossoming threat, the National Weather Service (NWS) has requested funding within its 2000 budget to begin national implementation of the Advanced Hydrologic Prediction System (AHPS). With this system in place the NWS will be able to utilize precipitation and climate predictions to provide extended probabilistic river forecasts for risk-based decisions. In addition to flood and drought mitigation benefits, extended river forecasts will benefit water resource managers in decision making regarding water supply, agriculture, navigation, hydropower, and ecosystems. It's estimated that AHPS, if implemented nationwide, would save lives and provide $677 million per year in economic benefits. AHPS is used currently on the Des Moines River basin in Iowa and will be implemented soon on the Minnesota River basin in Minnesota. Experience gained from user interaction is leading to refined and enhanced product formats and displays. This discussion will elaborate on the technical requirements associated with AHPS implementation, its enhanced products and informational displays, and further refinements based on customer feedback. C1 Natl Weather Serv, N Cent River Forecast Ctr, Chanhassen, MN 55317 USA. NOAA, Natl Weather Serv, Off Hydrol, Silver Spring, MD 20910 USA. RP Natl Weather Serv, N Cent River Forecast Ctr, 1733 Lake Dr W, Chanhassen, MN 55317 USA. EM dean.braatz@noaa.gov NR 8 TC 8 Z9 9 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 27 PY 1999 VL 104 IS D16 BP 19655 EP 19660 DI 10.1029/1999JD900051 PG 6 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 230CY UT WOS:000082235300049 ER PT J AU Herndon, SC Froyd, KD Lovejoy, ER Ravishankara, AR AF Herndon, SC Froyd, KD Lovejoy, ER Ravishankara, AR TI How rapidly does the SH radical react with N2O? SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID ABSOLUTE RATE; H2S; KINETICS AB The reaction of SH radical with N2O was investigated by using two complementary experimental methods: (a) a pulsed photolysis apparatus where SH was detected via laser-induced fluorescence and (b) a discharge flow tube where SH was detected via chemical ionization mass spectrometry. The rate coefficient for this reaction, k(1), was found to be less than 5 x 10(-16) cm(3) molecule(-1) s(-1) at 298 K, in contrast to the large value reported in the literature [Ravichandran; et al. Chem. Phys. Lett. 1994, 217, 375-379]. Secondary reactions were deduced to be unimportant in our system. Some possible reasons for the previously reported high value are presented. The low value of k(1) makes the oxidation of SH by N2O and removal of N2O by SH unimportant in the earth's atmosphere. C1 Univ Colorado, Dept Chem & Biochem, Boulder, CO 80309 USA. Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. NOAA, Aeron Lab, Boulder, CO 80303 USA. RP Ravishankara, AR (reprint author), NOAA, Environm Res Lab, R E AL2, 325 Broadway, Boulder, CO 80303 USA. RI Froyd, Karl/H-6607-2013; Ravishankara, Akkihebbal/A-2914-2011 NR 20 TC 6 Z9 6 U1 0 U2 3 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 AUG 26 PY 1999 VL 103 IS 34 BP 6778 EP 6785 DI 10.1021/jp9911853 PG 8 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 231WY UT WOS:000082335400012 ER PT J AU Lagalante, AF Clarke, AM Bruno, TJ AF Lagalante, AF Clarke, AM Bruno, TJ TI Measurement and modeling of the water-R143A partition coefficients of organic solutes using a linear solvation energy relationship SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID SUPERCRITICAL-FLUID CHROMATOGRAPHY; CARBON-DIOXIDE; SOLVATOCHROMIC PARAMETERS; WATER; SOLVENT; PREDICTION; EQUATION; OCTANOL; REFRIGERANTS; SOLUBILITY AB The water-R143a partition coefficients for a set of thirteen organic solutes have been measured using high-pressure spectroscopy. Water partition coefficients of the organic solutes were measured in the gas and supercritical phases of 1,1,1-trifluoroethane (R143a). A linear solvation energy relationship (LSER) was developed to predict the measured water-R143a partition coefficients using the Abraham descriptors of the solute and an additional solvent descriptor as independent variables. Considering the entire water-R143a partition coefficient data, the LSER model has an average absolute relative deviation of 49.5%. Considering only the data above the critical density of R143a, the LSER has an average absolute relative deviation of 40.7%. C1 Natl Inst Stand & Technol, Phys & Chem Properties Div 838 00, Boulder, CO 80303 USA. RP Lagalante, AF (reprint author), Natl Inst Stand & Technol, Phys & Chem Properties Div 838 00, 325 Broadway, Boulder, CO 80303 USA. NR 23 TC 9 Z9 9 U1 1 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5647 J9 J PHYS CHEM B JI J. Phys. Chem. B PD AUG 26 PY 1999 VL 103 IS 34 BP 7319 EP 7323 DI 10.1021/jp991264e PG 5 WC Chemistry, Physical SC Chemistry GA 231XB UT WOS:000082335700035 ER PT J AU Irikura, KK AF Irikura, KK TI The ionization energy of CF3: When does entropy matter in gas-phase reactions? SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID KINETIC METHOD; STATE; THERMOCHEMISTRY; MOLECULES; PHOTOIONIZATION; SPECTROSCOPY; DISSOCIATION; ATTACHMENT; DEPENDENCE; CATION AB A minor controversy has emerged recently over the value of the ionization energy of the trifluoromethyl radical, CF3. Solid evidence appears to support both high values; IEa approximate to 9.05 eV, and low values, IEa approximate to 8.65 eV. Examining the assumptions made in the analysis of the various experimental results shows that the root of the discrepancy is the role of entropy in low-pressure, gas-phase ion chemistry. The proper treatment of entropy has, itself, been a more fundamental controversy for a long time. In the zero-pressure limit, conservation of energy (Delta E) in a molecular collision is the primary consideration, but at the high-pressure limit, the free energy (Delta G) dictates the outcome of a reaction: what pressures qualify as "high"? (Henchman, M.; et al. In Structure/Reactivity and Thermochemistry of Ions; Ausloos, P., Lias, S. G., Eds.; Reidel: Dordrecht, The Netherlands, 1987, pp 381-399). The present paper does not achieve any fundamental resolution of the entropy question. However, it does demonstrate that many discrepancies involving CF3 are eliminated (in favor of the higher values of the ionization energy) when the free energy model is used. This result suggests that entropy remains important at lower pressures than many investigators now presume. C1 NIST, Phys & Chem Properties Div, Gaithersburg, MD 20899 USA. RP Irikura, KK (reprint author), NIST, Phys & Chem Properties Div, Gaithersburg, MD 20899 USA. RI Irikura, Karl/A-4266-2009 OI Irikura, Karl/0000-0001-7515-6761 NR 56 TC 30 Z9 30 U1 0 U2 3 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0002-7863 J9 J AM CHEM SOC JI J. Am. Chem. Soc. PD AUG 25 PY 1999 VL 121 IS 33 BP 7689 EP 7695 DI 10.1021/ja991350s PG 7 WC Chemistry, Multidisciplinary SC Chemistry GA 232WM UT WOS:000082393000026 ER PT J AU Lovejoy, ER AF Lovejoy, ER TI Ion trap studies of H+(H2SO4)(m)(H2O)(n) reactions with water, ammonia, and a variety of organic compounds SO INTERNATIONAL JOURNAL OF MASS SPECTROMETRY LA English DT Article DE ion trap; kinetics; protonated sulfuric acid; water clusters ID GAS-PHASE; PROTONATED WATER; CLUSTERS; ACETONITRILE; H2O; STRATOSPHERE; DISSOCIATION; ASSOCIATION; STABILITIES; NUCLEATION AB Rate coefficients and products are reported for the reactions of protonated sulfuric acid and water clusters H+(H2SO4)(m)(H2O)(n) with water, ammonia, and a variety of organic compounds. The cluster ions were generated in an external ion source and the reactions were studied in a quadrupole ion trap. These data yield the stabilities of H+H2SO4(H2O)(n=1-3). The implications of these results to the understanding of the role of H2SO4 in atmospheric ion chemistry are discussed. Effective internal temperatures of trapped H+(H2O)(n=3,4) and H+(NH3)(3) are also derived from kinetics of the unimolecular decomposition in the ion trap. (Int J Mass Spectrom 190/191 (1999) 231-241) (C) 1999 Elsevier Science B.V. C1 NOAA, Aeron Lab, Boulder, CO 80303 USA. RP Lovejoy, ER (reprint author), NOAA, Aeron Lab, 325 Broadway, Boulder, CO 80303 USA. NR 36 TC 14 Z9 14 U1 1 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1387-3806 J9 INT J MASS SPECTROM JI Int. J. Mass Spectrom. PD AUG 23 PY 1999 VL 191 BP 231 EP 241 DI 10.1016/S1387-3806(99)00006-8 PG 11 WC Physics, Atomic, Molecular & Chemical; Spectroscopy SC Physics; Spectroscopy GA 229EE UT WOS:000082179900022 ER PT J AU Alamo, RG Isasi, JR Kim, MH Mandelkern, L VanderHart, DL AF Alamo, RG Isasi, JR Kim, MH Mandelkern, L VanderHart, DL TI Thermal and structural behavior of metallocene-type random propylene copolymers. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 Florida A&M Univ, Dept Chem Engn, Tallahassee, FL 32310 USA. Florida State Univ, Coll Engn, Tallahassee, FL 32310 USA. Florida State Univ, Inst Mol Biophys, Tallahassee, FL 32306 USA. NIST, Div Polymers, Gaithersburg, MD 20899 USA. RI Isasi, Jose Ramon/L-6308-2014 OI Isasi, Jose Ramon/0000-0002-0481-5800 NR 0 TC 0 Z9 0 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD AUG 22 PY 1999 VL 218 MA 244-PMSE BP U671 EP U672 PN 2 PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA 226RA UT WOS:000082034002039 ER PT J AU Balsara, NP Lee, JH Jeon, HS Hammouda, BW AF Balsara, NP Lee, JH Jeon, HS Hammouda, BW TI Surfactancy of a block copolymer under high pressure. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 Polytech Univ, Dept Chem Engn, Brooklyn, NY 11201 USA. NIST, Gaithersburg, MD 20899 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD AUG 22 PY 1999 VL 218 MA 237-PMSE BP U669 EP U670 PN 2 PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA 226RA UT WOS:000082034002032 ER PT J AU Barnes, JD Kolb, R Barnes, KA Nakatani, AI Hammouda, B AF Barnes, JD Kolb, R Barnes, KA Nakatani, AI Hammouda, B TI Microstructure analysis using temperature-induced contrast variation in small-angle scattering. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 Natl Inst Stand & Technol, Div Polymer, Gaithersburg, MD 20899 USA. Exxon Res & Engn Co, Annandale, NJ 08801 USA. NIST, Div Polymers, Gaithersburg, MD 20899 USA. NIST, Ctr Neutron Res, Gaithersburg, MD 20899 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD AUG 22 PY 1999 VL 218 MA 265-PMSE BP U678 EP U678 PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 226RA UT WOS:000082034002060 ER PT J AU Brown, CM Yildirim, T Neumann, D AF Brown, CM Yildirim, T Neumann, D TI Dynamics of hydrogen in single-walled nanotubes. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 Univ Maryland, Dept Mech & Nucl Engn, College Pk, MD 20749 USA. NIST, Ctr Neutron Res, Gaithersburg, MD 20899 USA. RI yildirim, taner/A-1290-2009 NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD AUG 22 PY 1999 VL 218 MA 13-MTLS BP U723 EP U723 PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 226RA UT WOS:000082034002185 ER PT J AU Callicoatt, BE Lineberger, WC AF Callicoatt, BE Lineberger, WC TI Time-resolved dynamics of transient neutrals. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 Univ Colorado, Boulder, CO 80309 USA. Natl Inst Stand & Technol, Boulder, CO 80309 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD AUG 22 PY 1999 VL 218 MA 325-PHYS BP U366 EP U366 PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 226RA UT WOS:000082034001048 ER PT J AU Coxon, B Sari, N Pozsgay, V AF Coxon, B Sari, N Pozsgay, V TI NMR spectroscopy end molecular dynamics of a synthetic octasaccharide fragment of the O-polysaccharide of Shigella dysenteriae type 1. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NIST, Div Biotechnol, Gaithersburg, MD 20899 USA. NICHHD, Dev & Mol Immun Lab, NIH, Bethesda, MD 20892 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD AUG 22 PY 1999 VL 218 MA 65-CARB BP U200 EP U200 PN 1 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 226QZ UT WOS:000082033900545 ER PT J AU da Costa, CT Dalluge, JJ Margolis, SA Horton, D AF da Costa, CT Dalluge, JJ Margolis, SA Horton, D TI Liquid chromatography atmospheric-pressure chemical ionization mass spectrometry (LC-APCI-MS) for identification of flavanols and anthocyanins in plant extracts. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 American Univ, Dept Chem, Washington, DC 20016 USA. Natl Inst Stand & Technol, Div Analyt Chem, Gaithersburg, MD 20899 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD AUG 22 PY 1999 VL 218 MA 71-CARB BP U202 EP U202 PN 1 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 226QZ UT WOS:000082033900551 ER PT J AU Ding, JH McAvoy, TJ Adomaitis, R Semancik, S Cavicchi, R AF Ding, JH McAvoy, TJ Adomaitis, R Semancik, S Cavicchi, R TI Modeling micro-hotplate chemical gas sensors. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 Univ Maryland, Dept Chem Engn, College Pk, MD 20742 USA. Natl Inst Stand & Technol, Chem Sci & Technol Lab, Gaithersburg, MD 20899 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD AUG 22 PY 1999 VL 218 MA 125-NUCL BP U1065 EP U1065 PN 1 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 226QZ UT WOS:000082033903190 ER PT J AU Douglas, JF AF Douglas, JF TI Influence of polymer-polymer and polymer-surface interactions on the formation and swelling of end-grafted polymer layers. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NIST, Gaithersburg, MD 20899 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD AUG 22 PY 1999 VL 218 MA 275-POLY BP U476 EP U476 PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 226RA UT WOS:000082034001416 ER PT J AU Fraser, GT Walker, ARH Lovas, FJ Suenram, RD AF Fraser, GT Walker, ARH Lovas, FJ Suenram, RD TI Experimental model studies of the peptide bond. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 Natl Inst Stand & Technol, Opt Technol Div, Gaithersburg, MD 20899 USA. RI Hight Walker, Angela/C-3373-2009 OI Hight Walker, Angela/0000-0003-1385-0672 NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD AUG 22 PY 1999 VL 218 MA 277-PHYS BP U353 EP U353 PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 226RA UT WOS:000082034001000 ER PT J AU Giannelis, EP Chen, H Demeter, J Manias, E Hadjichristidis, N Karim, A AF Giannelis, EP Chen, H Demeter, J Manias, E Hadjichristidis, N Karim, A TI Mobility of polymers in nanometer slits: Kinetics of polymer melt intercalation in layered silicates. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 Cornell Univ, Dept Mat Sci & Engn, Ithaca, NY 14853 USA. Univ Athens, Dept Chem, GR-10679 Athens, Greece. NIST, Div Polymer, Gaithersburg, MD 20899 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD AUG 22 PY 1999 VL 218 MA 280-POLY BP U477 EP U478 PN 2 PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA 226RA UT WOS:000082034001421 ER PT J AU Gilliland, GL Fagan, P Westbrook, J Berman, H Bourne, P Arzberger, P AF Gilliland, GL Fagan, P Westbrook, J Berman, H Bourne, P Arzberger, P TI Uniformity and the new Protein Data Bank. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Rutgers State Univ, Rutgers, NJ USA. Univ Calif San Diego, San Diego, CA 92103 USA. RI Bourne, Philip/C-2073-2008 NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD AUG 22 PY 1999 VL 218 MA 62-CINF BP U367 EP U368 PN 1 PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA 226QZ UT WOS:000082033901099 ER PT J AU Hunston, DL Holmes, GA Peterson, RC McDonough, WG AF Hunston, DL Holmes, GA Peterson, RC McDonough, WG TI Strain rate effects in the single fiber fragmentation test for fiber-matrix adhesion. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 Natl Inst Stand & Technol, Div Polymers, Gaithersburg, MD 20899 USA. Rutgers State Univ, New Brunswick, NJ 08903 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD AUG 22 PY 1999 VL 218 MA 251-PMSE BP U673 EP U674 PN 2 PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA 226RA UT WOS:000082034002046 ER PT J AU Kent, MS Majewski, J Lee, LT Satija, S AF Kent, MS Majewski, J Lee, LT Satija, S TI Model study of tethered chains using Langmuir monolayers of diblock copolymers. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 Natl Inst Stand & Technol, Ctr Neutron Res, Gaithersburg, MD 20899 USA. Leon Brillouin Lab, Saclay, France. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. RI Lujan Center, LANL/G-4896-2012 NR 0 TC 0 Z9 0 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD AUG 22 PY 1999 VL 218 MA 562-POLY BP U558 EP U558 PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 226RA UT WOS:000082034001703 ER PT J AU Lefebvre, AA Lee, JH Balsara, NP Hammouda, B AF Lefebvre, AA Lee, JH Balsara, NP Hammouda, B TI Time-temperature superposition law for phase separation kinetics in polymer blends. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 Polytech Univ, Dept Chem Engn Chem & Mat Sci, Metrotech Ctr 6, Brooklyn, NY 11201 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NR 0 TC 0 Z9 0 U1 1 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD AUG 22 PY 1999 VL 218 MA 113-PMSE BP U635 EP U635 PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 226RA UT WOS:000082034001909 ER PT J AU Meredith, JC Johnston, KP AF Meredith, JC Johnston, KP TI Polymer adsorption colloid stability in supercritical fluids: Monte Carlo simulation. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NIST Polymers Div, Div Polymers, Gaithersburg, MD 20878 USA. Univ Texas, Austin, TX 78712 USA. RI Meredith, Carson/B-3323-2009 OI Meredith, Carson/0000-0003-2519-5003 NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD AUG 22 PY 1999 VL 218 MA 352-PHYS BP U373 EP U373 PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 226RA UT WOS:000082034001074 ER PT J AU Meredith, JC Johnston, KP AF Meredith, JC Johnston, KP TI Density dependence of homopolymer adsorption and colloidal interaction forces in supercritical solvents. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NIST, Div Polymers, Gaithersburg, MD 20878 USA. Univ Texas, Austin, TX 78712 USA. RI Meredith, Carson/B-3323-2009 OI Meredith, Carson/0000-0003-2519-5003 NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD AUG 22 PY 1999 VL 218 MA 78-COLL BP U421 EP U421 PN 1 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 226QZ UT WOS:000082033901272 ER PT J AU Modi, MA Krishnamoorti, R Green, P Karim, A AF Modi, MA Krishnamoorti, R Green, P Karim, A TI Phase behavior and crystallization of thin-film polyolefin blends. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 Univ Houston, Dept Chem Engn, Houston, TX 77204 USA. Univ Texas, Austin, TX 78712 USA. NIST, Gaithersburg, MD 20899 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD AUG 22 PY 1999 VL 218 MA 169-PMSE BP U650 EP U650 PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 226RA UT WOS:000082034001964 ER PT J AU Morgan, AB Jurs, JL Tour, JM AF Morgan, AB Jurs, JL Tour, JM TI Aromatic boronic acid flame-retardant polymer additives: Synthesis and flame-retardant testing. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NIST, Gaithersburg, MD 20899 USA. Univ S Carolina, Dept Chem & Biochem, Columbia, SC 29208 USA. RI Morgan, Alexander/A-9672-2009 NR 0 TC 0 Z9 0 U1 0 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD AUG 22 PY 1999 VL 218 MA 28-POLY BP U406 EP U407 PN 2 PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA 226RA UT WOS:000082034001173 ER PT J AU Ober, CK Xiang, ML Char, K Genzer, J Sivaniah, E Kramer, EJ Fischer, DA AF Ober, CK Xiang, ML Char, K Genzer, J Sivaniah, E Kramer, EJ Fischer, DA TI Block copolymers with low surface energy, liquid-crystalline segments: The interplay of surface and bulk liquid crystallinity. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 Cornell Univ, Dept Mat Sci & Engn, Ithaca, NY 14853 USA. Univ Calif Santa Barbara, Dept Mat, Santa Barbara, CA 93106 USA. NIST, Gaithersburg, MD 20899 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD AUG 22 PY 1999 VL 218 MA 310-POLY BP U486 EP U487 PN 2 PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA 226RA UT WOS:000082034001451 ER PT J AU Poirier, GE AF Poirier, GE TI Structural phases of alkanethiol monolayers. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NIST, Gaithersburg, MD 20899 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD AUG 22 PY 1999 VL 218 MA 115-ANYL BP U160 EP U160 PN 1 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 226QZ UT WOS:000082033900427 ER PT J AU Powell, LJ AF Powell, LJ TI Glass ceiling: Cracking, but still there. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NIST, Gaithersburg, MD 20899 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD AUG 22 PY 1999 VL 218 MA 5-PROF BP U690 EP U691 PN 2 PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA 226RA UT WOS:000082034002101 ER PT J AU Reid, JP Loomis, RA Leone, SR AF Reid, JP Loomis, RA Leone, SR TI Competition between adiabatic and nonadiabatic dynamics in the photofragmentation of ammonia. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 Univ Colorado, JILA, Boulder, CO 80309 USA. NIST, Boulder, CO 80309 USA. Washington Univ, Dept Chem, St Louis, MO 63130 USA. RI Reid, Jonathan/D-9411-2013 NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD AUG 22 PY 1999 VL 218 MA 42-PHYS BP U286 EP U286 PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 226RA UT WOS:000082034000777 ER PT J AU Rice, CP Klingebiel, U Poster, D AF Rice, CP Klingebiel, U Poster, D TI Chiral patterns of soil-aged pesticides (technical chlordane, BHC, and DDT). SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 USDA, Environm Chem Lab, Beltsville Agr Res Ctr, Beltsville, MD 20705 USA. Natl Inst Stand & Technol, Div Analyt Chem, Gaithersburg, MD 20899 USA. NR 0 TC 0 Z9 0 U1 1 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD AUG 22 PY 1999 VL 218 MA 88-ENVR BP U569 EP U569 PN 1 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 226QZ UT WOS:000082033901727 ER PT J AU Satija, SK Ivkov, R Butler, P Fetters, LJ AF Satija, SK Ivkov, R Butler, P Fetters, LJ TI Neutron reflectivity of grafted polymer brushes under shear. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NIST, Ctr Neutron Res, Gaithersburg, MD 20854 USA. Exxon Res & Engn Co, Annandale, NJ 08801 USA. RI Butler, Paul/D-7368-2011 NR 0 TC 0 Z9 0 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD AUG 22 PY 1999 VL 218 MA 277-POLY BP U476 EP U477 PN 2 PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA 226RA UT WOS:000082034001418 ER PT J AU Semancik, S Cavicchi, RE Walton, RM Suehle, JS AF Semancik, S Cavicchi, RE Walton, RM Suehle, JS TI Microarrays as platforms for gas microsensor development and efficient materials research. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 Natl Inst Stand & Technol, Chem Sci & Technol Lab, Gaithersburg, MD 20899 USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD AUG 22 PY 1999 VL 218 MA 126-NUCL BP U1065 EP U1065 PN 1 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 226QZ UT WOS:000082033903191 ER PT J AU Snyder, CR Mopsik, FI Marand, H Alizadeh, A Sohn, SM AF Snyder, CR Mopsik, FI Marand, H Alizadeh, A Sohn, SM TI Time-domain dielectric spectroscopy analysis of the amorphous phase in semicrystalline polycarbonate. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 Natl Inst Stand & Technol, Div Polymers, Gaithersburg, MD 20899 USA. Virginia Tech, Dept Chem, Blacksburg, VA 24061 USA. RI Snyder, Chad/B-4957-2008 OI Snyder, Chad/0000-0002-2916-9809 NR 0 TC 0 Z9 0 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD AUG 22 PY 1999 VL 218 MA 139-PMSE BP U641 EP U641 PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 226RA UT WOS:000082034001934 ER PT J AU Steel, AB Levicky, R Herne, TM Tarlov, MJ AF Steel, AB Levicky, R Herne, TM Tarlov, MJ TI Electrochemical quantitation of DNA immobilized on gold. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 Gene Log Inc, DNA Chip R&D, Gaithersburg, MD 20878 USA. Columbia Univ, Dept Chem Engn, New York, NY 10027 USA. NIST, Proc Sensing Grp, Gaithersburg, MD 20899 USA. NR 0 TC 0 Z9 0 U1 3 U2 15 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD AUG 22 PY 1999 VL 218 MA 158-ANYL BP U173 EP U173 PN 1 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 226QZ UT WOS:000082033900471 ER PT J AU Stein, SE Ausloos, P Clifton, CL Klassen, JK Lias, SG Mikaya, AI Sparkman, OD Tchekhovskoi, DV Zaikin, V Zhu, D AF Stein, SE Ausloos, P Clifton, CL Klassen, JK Lias, SG Mikaya, AI Sparkman, OD Tchekhovskoi, DV Zaikin, V Zhu, D TI Evaluation of the NIST/EPA/NIH Mass Spectral Library. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NIST, Phys & Chem Properties Div, Gaithersburg, MD 20899 USA. AV Topchiev Petrochem Synth Inst, Moscow 117912, Russia. Chinese Acad Sci, Dalian Inst Chem Phys, Dalian, Peoples R China. RI Tchekhovskoi, Dmitrii/J-2319-2014 NR 0 TC 4 Z9 4 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD AUG 22 PY 1999 VL 218 MA 63-CINF BP U368 EP U368 PN 1 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 226QZ UT WOS:000082033901100 ER PT J AU Tsai, AM Neumann, DA AF Tsai, AM Neumann, DA TI Change in water dynamics in the presence of mono- and disaccharides. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 Natl Inst Stand & Technol, Ctr Neutron Res, Gaithersburg, MD 20899 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD AUG 22 PY 1999 VL 218 MA 159-PHYS BP U319 EP U319 PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 226RA UT WOS:000082034000887 ER PT J AU Tsang, W AF Tsang, W TI Thermal stability of organic radicals. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 NIST, Gaithersburg, MD 20899 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD AUG 22 PY 1999 VL 218 MA 1-FUEL BP U603 EP U603 PN 1 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 226QZ UT WOS:000082033901817 ER PT J AU Vaida, V Tuck, AF Goss, LM Daniel, JS Kjaergaard, H AF Vaida, V Tuck, AF Goss, LM Daniel, JS Kjaergaard, H TI Spectroscopic properties of water clusters: Relevance to atmospheric radiative transfer. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 Univ Colorado, Dept Chem & Biochem, Boulder, CO 80309 USA. NOAA, Aeron Lab, Boulder, CO 80303 USA. Whitman Coll, Walla Walla, OR USA. NOAA, Aeron Lab, Boulder, CO 80303 USA. Univ Otago, Dunedin, New Zealand. RI Daniel, John/D-9324-2011 NR 0 TC 0 Z9 0 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD AUG 22 PY 1999 VL 218 MA 403-PHYS BP U387 EP U387 PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 226RA UT WOS:000082034001120 ER PT J AU Woodward, JT Walker, ML Meuse, C Vanderah, D Plant, AL AF Woodward, JT Walker, ML Meuse, C Vanderah, D Plant, AL TI Alkanethiol multilayer formation on oxidized gold substrates. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 Natl Inst Stand & Technol, Div Biotechnol, Gaithersburg, MD 20899 USA. Natl Inst Stand & Technol, Surface & Microanal Sci Div, Gaithersburg, MD 20899 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD AUG 22 PY 1999 VL 218 MA 153-PHYS BP U317 EP U318 PN 2 PG 2 WC Chemistry, Multidisciplinary SC Chemistry GA 226RA UT WOS:000082034000881 ER PT J AU Yi, XH Pellegrino, J AF Yi, XH Pellegrino, J TI Diffusion of water/acetone mixture in poly(propylene) from FTIR-ATR spectroscopy. SO ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY LA English DT Meeting Abstract C1 Natl Inst Stand & Technol, Chem Sci & Technol Lab, Boulder, CO 80303 USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0065-7727 J9 ABSTR PAP AM CHEM S JI Abstr. Pap. Am. Chem. Soc. PD AUG 22 PY 1999 VL 218 MA 22-MACR BP U712 EP U712 PN 2 PG 1 WC Chemistry, Multidisciplinary SC Chemistry GA 226RA UT WOS:000082034002156 ER PT J AU Brugh, DJ Suenram, RD Stevens, WJ AF Brugh, DJ Suenram, RD Stevens, WJ TI Fourier transform microwave spectroscopy of jet-cooled ZrO2 produced by laser vaporization SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID ELECTRIC-DIPOLE MOMENTS; COMPACT EFFECTIVE POTENTIALS; DENSITY-FUNCTIONAL THEORY; TRANSITION-METAL OXIDES; EXPONENT BASIS-SETS; ROTATIONAL SPECTRA; ATOMS; MOLECULES; EFFICIENT AB The pure rotational spectrum of the asymmetric top ZrO2 has been collected using a Fourier transform microwave spectrometer that employed a laser ablation molecular beam source. Four rotational transitions for each of five (ZrO2)-O-16 isotopomers have been recorded. The rotational constants of the (ZrO2)-Zr-90-O-16 isotope were determined to be A = 19 881.352 MHz +/- 0.068 MHz, B = 7693.895 MHz +/- 0.021 MHz, and C = 5533.111 MHz +/- 0.036 MHz. The r(0) structure was determined to possess a Zr-O bond length of 1.7710 Angstrom +/- 0.0007 Angstrom, and an O-Zr-O bond angle of 108.11 degrees +/- 0.08 degrees. The electric dipole moment has been measured for the (ZrO2)-Zr-90-O-16 isotope and found to be mu(b) = 26.02x10(-30) C.m +/- 0.07x10(-30) C.m [7.80 Debye +/- 0.02 Debye]. The nuclear quadrupole hyperfine structure for the (ZrO2)-Zr-91-O-16 isotope has also been recorded and analyzed, yielding chi(aa) = 115.94 MHz +/- 0.16 MHz, chi(bb) = -37.55 MHz +/- 0.33 MHz, and chi(cc) = -78.39 MHz +/- 0.16 MHz. High-level density functional theory calculations yield a structure that agrees well with the values determined experimentally. Several new transitions assigned to (ZrO)-O-16 were also recorded in the course of this study, and these were analyzed to extract values of B-e, alpha(e), and gamma(e) for four isotopomers. (C) 1999 American Institute of Physics. [S0021-9606(99)01432-4]. C1 Natl Inst Stand & Technol, Opt Technol Div, Gaithersburg, MD 20899 USA. Natl Inst Stand & Technol, Phys & Chem Properties Div, Gaithersburg, MD 20899 USA. RP Brugh, DJ (reprint author), Natl Inst Stand & Technol, Opt Technol Div, Gaithersburg, MD 20899 USA. NR 37 TC 34 Z9 35 U1 1 U2 3 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD AUG 22 PY 1999 VL 111 IS 8 BP 3526 EP 3535 DI 10.1063/1.479674 PG 10 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 224ZF UT WOS:000081929300026 ER PT J AU Romani, RW Miller, AJ Cabrera, B Figueroa-Feliciano, E Nam, SW AF Romani, RW Miller, AJ Cabrera, B Figueroa-Feliciano, E Nam, SW TI First astronomical application of a cryogenic transition edge sensor spectrophotometer SO ASTROPHYSICAL JOURNAL LA English DT Article DE instrumentation : detectors pulsars : individual (PSR B0531+21) ID SUPERCONDUCTING TUNNEL-JUNCTIONS; ULTRAVIOLET; PULSAR AB We report on the first astronomical observations with a photon-counting pixel detector that provides arrival time (delta t = 100 ns) and energy (delta E-gamma less than or equal to 0.15 eV) resolved measurements from the near-IR through the near UV. Our test observations were performed by coupling this transition edge sensor device to a 0.6 m telescope; we have obtained the first simultaneous optical near-IR phase-resolved spectra of the Crab pulsar. A varying infrared turnover gives evidence of self-absorption in the pulsar plasma. The potential of such detectors in imaging arrays from a space platform is briefly described. C1 Stanford Univ, Dept Phys, Stanford, CA 94305 USA. Natl Inst Stand & Technol, Boulder, CO 80303 USA. RP Romani, RW (reprint author), Stanford Univ, Dept Phys, Stanford, CA 94305 USA. NR 19 TC 41 Z9 41 U1 0 U2 7 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD AUG 20 PY 1999 VL 521 IS 2 BP L153 EP L156 DI 10.1086/312202 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 226KA UT WOS:000082018100019 ER PT J AU Perry, KD Cahill, TA Schnell, RC Harris, JM AF Perry, KD Cahill, TA Schnell, RC Harris, JM TI Long-range transport of anthropogenic aerosols to the National Oceanic and Atmospheric Administration baseline station at Mauna Loa Observatory, Hawaii SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID PHOTOCHEMISTRY EXPERIMENT 2; REMOTE NORTH PACIFIC; UNITED-STATES; SOUTH-POLE; ASIAN DUST; BLACK CARBON; ORGANIC AEROSOLS; TRACE-ELEMENTS; VARIABILITY; ABSORPTION AB Size-segregated measurements of aerosol mass and composition are used to determine the composition and seasonal variations of natural and anthropogenic aerosols at Mauna Loa Observatory (MLO) from 1993 through 1996. Although the springtime transport of Asian dust to MLO is a well-documented phenomenon, this study shows that fine anthropogenic aerosols, including sulfur, black carbon, and enriched trace metals such as As, Cu, Pb, and Zn, are also routinely transported to MLO each spring. It is estimated that at least one third of the sulfate measured at MLO during the spring is anthropogenic. In addition, indirect measurements indicate that the organic aerosol concentrations are often comparable to the sulfate concentrations. This study also combines size- and time-resolved aerosol composition measurements with isentropic, backward air-mass trajectories and gas measurements of Rn-222, CH4, CO, and CO2 to identify some potential source regions of the anthropogenic aerosols. Three types of long-range transport episodes are identified: (1) anthropogenic aerosols mixed with Asian dust, (2) Asian pollution with relatively small amounts of soil dust, and (3) biomass burning emissions from North America. This study shows that anthropogenic aerosols and gases can be efficiently transported to MLO from both Asia and North America during the spring. C1 Univ Calif Davis, Dept Land Air & Water Resources, Davis, CA 95616 USA. NOAA, Climate Monitoring & Diagnost Lab, Boulder, CO 80303 USA. RP Perry, KD (reprint author), San Jose State Univ, Dept Meteorol, 1 Washington Sq, San Jose, CA 95192 USA. EM perry@metsun1.sjsu.edu; tacahill@ucdavis.edu; rschnell@cmdl.noaa.gov; jharris@icmdl.noaa.gov NR 85 TC 108 Z9 108 U1 1 U2 17 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 20 PY 1999 VL 104 IS D15 BP 18521 EP 18533 DI 10.1029/1998JD100083 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 228GJ UT WOS:000082128500004 ER PT J AU Rinsland, CP Goldman, A Murcray, FJ Stephen, TM Pougatchev, NS Fishman, J David, SJ Blatherwick, RD Novelli, PC Jones, NB Connor, BJ AF Rinsland, CP Goldman, A Murcray, FJ Stephen, TM Pougatchev, NS Fishman, J David, SJ Blatherwick, RD Novelli, PC Jones, NB Connor, BJ TI Infrared solar spectroscopic measurements of free tropospheric CO, C2H6, and HCN above Mauna Loa, Hawaii: Seasonal variations and evidence for enhanced emissions from the Southeast Asian tropical fires of 1997-1998 SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Review ID VERTICAL COLUMN ABUNDANCES; CARBON-MONOXIDE; ATMOSPHERIC GASES; HYDROGEN-CYANIDE; TRACE GASES; KITT PEAK; OZONE; ETHANE; SCALE; DISTRIBUTIONS AB High spectral resolution (0.003 cm(-1)) infrared solar absorption measurements of CO, C2H6, and HCN have been recorded at the Network for the Detection of Stratospheric Change station on Mauna Loa, Hawaii, (19.5 degrees N, 155.6 degrees W, altitude 3.4 km). The observations were obtained on over 250 days between August 1995 and February 1998. Column measurements are reported for the 3.4-16 km altitude region, which corresponds approximately to the free troposphere above the station. average CO mixing ratios computed for this layer have been compared with flask sampling CO measurements obtained in situ at the station during the same time period. Both show asymmetrical seasonal cycles superimposed on significant variability. The first 2 years of observations exhibit a broad January-April maximum and a sharper CO minimum during late summer. The C2H6 and CO 3.4-16 km columns were highly correlated throughout the observing period with the C2H6/CO slope intermediate between higher and lower values derived from similar infrared spectroscopic measurements at 32 degrees N and 45 degrees S latitude, respectively. Variable enhancements in CO, C2H6, and particularly HCN were observed beginning in about September 1997. The maximum HCN free tropospheric monthly mean column observed in November 1997 corresponds to an average 3.4-16 fim mixing ratio of 0.7 ppbv (1 ppbv = 10(-9) per unit volume), more than a factor of 3 above the background level. The HCN enhancements continued through the end of the observational series. Back-trajectory calculations suggest that the emissions originated at low northern latitudes in southeast Asia. Surface CO mixing ratios and the C2H6 tropospheric columns measured during the same time also showed anomalous autumn 1997 maxima. The intense and widespread tropical wild fires that burned during the strong El Nino warm phase of 1997-1998 are the likely source of the elevated emission products. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. Univ Denver, Dept Phys, Denver, CO 80208 USA. NIWA Climate, Lauder 9182, New Zealand. NOAA, Climate Monitoring & Diagnost Lab, Boulder, CO 80303 USA. Christopher Newport Univ, Dept Phys, Newport News, VA 23606 USA. RP Rinsland, CP (reprint author), NASA, Langley Res Ctr, Mail Stop 401A, Hampton, VA 23681 USA. RI Jones, Nicholas/G-5575-2011 OI Jones, Nicholas/0000-0002-0111-2368 NR 70 TC 60 Z9 60 U1 2 U2 5 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 20 PY 1999 VL 104 IS D15 BP 18667 EP 18680 DI 10.1029/1999JD900366 PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 228GJ UT WOS:000082128500013 ER PT J AU Khattatov, BV Gille, JC Lyjak, LV Brasseur, GP Dvortsov, VL Roche, AE Waters, JW AF Khattatov, BV Gille, JC Lyjak, LV Brasseur, GP Dvortsov, VL Roche, AE Waters, JW TI Assimilation of photochemically active species and a case analysis of UARS data SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID VARIATIONAL DATA ASSIMILATION; WEATHER-PREDICTION; SATELLITE; VORTICITY; ADJOINT; MODELS; RATES AB We present a short overview of applications of estimation theory in atmospheric chemistry and discuss some common methods of gridding and mapping of irregular satellite observations of chemical constituents. It is shown that these methods are unable to produce truly synoptic maps of short-lived photochemically active species due to insufficient temporal and spatial density of satellite observations. The only way to overcome this limitation is to supplement observations with prior independent information given, for instance, by atmospheric numerical models and/or climatologies. Objective approaches to combining such prior information with observations are commonly referred to as data assimilation. Mathematical basis of data assimilation known as optimal estimation equations is presented following Lorenc [1986]. Two particular techniques of data assimilation, the variational method and the extended Kalman filter, are briefly described, and their applications to time-dependent numerical photochemical models are discussed. We investigate validity of the linear approximation which is utilized in both methods, present time evolution of the linearization and covariance matrices, and discuss some of their properties. On the basis of ideas of Fisher and Lary [1995] we then employ a trajectory model and a photochemical box model for assimilation and mapping of the Upper Atmosphere Research Satellite (UARS) measurements of chemical species. The assimilation is performed using the variational technique and the extended Kalman filter, and results of bo th methods are presented and discussed. C1 Natl Ctr Atmospher Res, Boulder, CO 80307 USA. NOAA, Aeron Lab, Boulder, CO 80303 USA. Lockheed Res Lab, Palo Alto, CA 94304 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. RP Khattatov, BV (reprint author), Natl Ctr Atmospher Res, POB 3000, Boulder, CO 80307 USA. EM boris@ucar.edu NR 28 TC 56 Z9 58 U1 0 U2 0 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 20 PY 1999 VL 104 IS D15 BP 18715 EP 18737 DI 10.1029/1999JD900225 PG 23 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 228GJ UT WOS:000082128500017 ER PT J AU Miller, HL Sanders, RW Solomon, S AF Miller, HL Sanders, RW Solomon, S TI Observations and interpretation of column OClO seasonal cycles at two polar sites SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID NEAR-ULTRAVIOLET SPECTROSCOPY; POOR QUANTITATIVE INDICATOR; ANTARCTIC OZONE HOLE; MCMURDO-STATION; STRATOSPHERIC OCLO; CHLORINE ACTIVATION; VISIBLE SPECTROSCOPY; VERTICAL STRUCTURE; VOLCANIC AEROSOLS; NO2 AB OClO and NO2 slant column abundances have been measured by ground-based spectrographs in both the Arctic (Kangerlussuaq, Greenland, at 67.0 degrees N, 51.0 degrees W) and the Antarctic (McMurdo Station, Antarctica, at 77.8 degrees S, 166.6 degrees E). A key process for stratospheric ozone depletion is the activation of chlorine by heterogeneous reactions. Sunlight is also an essential ingredient in the catalytic cycles that destroy ozone. This data set illustrates the seasonal timing of autumnal chlorine activation and the springtime disappearance of active chlorine at two polar sites. As such, the data provide constraints for model calculations. In the Northern Hemisphere during the winters of 1994-1995 and 1995-1996, the OClO data show the seasonal onset of stratospheric chlorine activation in mid-December and seasonal disappearance of active chlorine in mid-March. The data also show the seasonal decline and recovery (in mid-March) of nitrogen dioxide levels. In the Southern Hemisphere during the winters of 1991, 1993, and 1996, similar chemical processing occurs during late April to early May and late September to early October. The role of several factors in determining the seasonal cycles of column OClO are probed through model studies. Observed cold temperatures and reactions on liquid sulfate aerosols appear to play a key role in producing the timing of the observed OClO seasonal cycle in the Northern Hemisphere. C1 NOAA, Aeron Lab, Boulder, CO 80303 USA. Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. RP Miller, HL (reprint author), Forschungszentrum Julich, Inst Chem & Dynam Geosphare, Inst Stratosphar Chem 1, D-52425 Julich, Germany. EM h.l.miller@fz-juelich.de; solomon@al.noaa.gov RI Miller, Henry/D-7628-2013 OI Miller, Henry/0000-0002-7155-8314 NR 43 TC 15 Z9 15 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 20 PY 1999 VL 104 IS D15 BP 18769 EP 18783 DI 10.1029/1999JD900301 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 228GJ UT WOS:000082128500020 ER PT J AU Dyer, SD Rochford, KB AF Dyer, SD Rochford, KB TI Low-coherence interferometric measurements of fibre Bragg grating dispersion SO ELECTRONICS LETTERS LA English DT Article ID REFLECTOMETRY AB Low-coherence interferometric measurements of dispersion in fibre Bragg gratings are presented. The group delay as a function of wavelength is obtained rapidly by Fourier-transform processing the interferogram, yielding results withib a few minutes. The experimental repeatability is shown to be better than 1 ps. C1 Natl Inst Stand & Technol, Div Optoelect, Boulder, CO 80303 USA. RP Dyer, SD (reprint author), Natl Inst Stand & Technol, Div Optoelect, 325 Broadway, Boulder, CO 80303 USA. NR 8 TC 29 Z9 31 U1 0 U2 1 PU IEE-INST ELEC ENG PI HERTFORD PA MICHAEL FARADAY HOUSE SIX HILLS WAY STEVENAGE, HERTFORD SG1 2AY, ENGLAND SN 0013-5194 J9 ELECTRON LETT JI Electron. Lett. PD AUG 19 PY 1999 VL 35 IS 17 BP 1485 EP 1486 DI 10.1049/el:19990986 PG 2 WC Engineering, Electrical & Electronic SC Engineering GA 232EP UT WOS:000082357300063 ER PT J AU Johnson, JE AF Johnson, JE TI Evaluation of a seawater equilibrator for shipboard analysis of dissolved oceanic trace gases SO ANALYTICA CHIMICA ACTA LA English DT Article DE equilibrator; trace gases ID CARBON-MONOXIDE; SEA-WATER; ATMOSPHERE; METHANE AB Equilibrators have been used for years to obtain gas phase samples for measurement of the partial pressure of dissolved trace gases in near surface seawater. For air-sea exchange studies these measurements assume (1) complete and instantaneous equilibration and (2) that the water sampled is representative of the water in contact with the atmosphere. We present a simple mathematical model to evaluate the factors that determine the equilibration time constant for any gas of known solubility and to determine the deviation from equilibrium that arises from any vent flow of air into the equilibrator headspace. Both these expressions are functionally dependent on a dimensionless equilibrator coefficient epsilon. The model predictions were tested using measurements under field conditions utilizing two gases of widely differing solubility, carbon dioxide and carbon monoxide, For both these gases we show that the value of epsilon for our particular equilibrator is about 0.3-0.4. We also present a depth profile of CO in the top 5 m of the open ocean which demonstrates that seawater sampled through a ship's water inlet at 5 m depth is representative of surface water. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Washington, Joint Inst Study Atmosphere & Ocean, Seattle, WA USA. NOAA, Pacific Marine Environm Lab, Seattle, WA 98115 USA. RP Johnson, JE (reprint author), Univ Washington, Joint Inst Study Atmosphere & Ocean, Seattle, WA USA. NR 14 TC 44 Z9 44 U1 3 U2 15 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0003-2670 J9 ANAL CHIM ACTA JI Anal. Chim. Acta PD AUG 16 PY 1999 VL 395 IS 1-2 BP 119 EP 132 DI 10.1016/S0003-2670(99)00361-X PG 14 WC Chemistry, Analytical SC Chemistry GA 227WX UT WOS:000082103900013 ER PT J AU Corwin, KL Kuppens, SJM Cho, D Wieman, CE AF Corwin, KL Kuppens, SJM Cho, D Wieman, CE TI Spin-polarized atoms in a circularly polarized optical dipole trap SO PHYSICAL REVIEW LETTERS LA English DT Article ID VAPOR; COLD AB The behavior of atoms in an optical far-off resonance trap is found to depend strongly on the trap polarization. Large loss rates occur unless the polarization is perfectly linear or perfectly circular, in which case exponential lifetimes up to 10 s are observed. Through optimization of trap loading, samples of 4 x 10(6) atoms are obtained in a circularly polarized trap. Spin polarization of 98(1)% is measured. This trap should prove useful for precision measurements such as beta-decay asymmetry and should make rf cooling possible in optical traps. C1 Natl Inst Stand & Technol, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. Univ Colorado, Boulder, CO 80309 USA. Univ Colorado, Dept Phys, Boulder, CO 80309 USA. Korea Univ, Dept Phys, Seoul 136701, South Korea. RP Corwin, KL (reprint author), Natl Inst Stand & Technol, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. RI Corwin, Kristan/A-1331-2013 NR 17 TC 46 Z9 46 U1 2 U2 3 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 AUG 16 PY 1999 VL 83 IS 7 BP 1311 EP 1314 DI 10.1103/PhysRevLett.83.1311 PG 4 WC Physics, Multidisciplinary SC Physics GA 227EY UT WOS:000082066600010 ER PT J AU Sander, LC Pursch, M Marker, B Wise, SA AF Sander, LC Pursch, M Marker, B Wise, SA TI Separation of carotenoid isomers by capillary electrochromatography with C-30 stationary phases SO ANALYTICAL CHEMISTRY LA English DT Article ID RIGID POLYMER MONOLITHS; PACKED CAPILLARIES; LIQUID-CHROMATOGRAPHY; GRADIENT ELUTION; PERFORMANCE; COLUMNS; MEDIA; NMR AB The use of a polymerically bonded C-30 stationary phase is demonstrated in capillary electrochromatography (CEC) for the separation of carotenoid isomers. Column selectivity in CEC was found to be equivalent to that observed with liquid chromatography (LC); however, CEC column efficiency was significantly improved over LC efficiency. Gradient elution capability was achieved by the combined use of a liquid chromatographic pump and a CEC apparatus. The separation of carotenoid isomers from food and algal extracts is demonstrated. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Sander, LC (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NR 32 TC 34 Z9 36 U1 0 U2 6 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0003-2700 J9 ANAL CHEM JI Anal. Chem. PD AUG 15 PY 1999 VL 71 IS 16 BP 3477 EP 3483 DI 10.1021/ac990311w PG 7 WC Chemistry, Analytical SC Chemistry GA 227HM UT WOS:000082075100024 ER PT J AU Langford, AO AF Langford, AO TI Stratosphere-troposphere exchange at the subtropical jet: contribution to the tropospheric ozone budget at midlatitudes SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID SOUTHERN OSCILLATION; TROPOPAUSE BREAK; CIRCULATION; INTRUSIONS; TRANSPORT; FOLD AB The interannual variability of the springtime maximum in free tropospheric ozone above Colorado is examined using 5-1/2 years (1993-1998) of Differential Absorption Lidar (DIAL) data. Year-to-year differences of up to 20% in the monthly mean mixing ratios are shown to be correlated with changes in the 200 hPa wind speed over the eastern Pacific that are associated with the El Nino/Southern Oscillation (ENSO). This correlation is attributed to variations in the intensity of stratosphere-troposphere exchange (STE) associated with the mean transverse circulation at the subtropical jet exit over the eastern Pacific. C1 NOAA, Aeron Lab, Boulder, CO 80303 USA. RP Langford, AO (reprint author), NOAA, Aeron Lab, 325 Broadway, Boulder, CO 80303 USA. RI Langford, Andrew/D-2323-2009 OI Langford, Andrew/0000-0002-2932-7061 NR 19 TC 24 Z9 30 U1 0 U2 5 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD AUG 15 PY 1999 VL 26 IS 16 BP 2449 EP 2452 DI 10.1029/1999GL900556 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 226GD UT WOS:000082011200011 ER PT J AU Fuselier, SA Onsager, TG AF Fuselier, SA Onsager, TG TI Comment on: "New observations of ion beams in the plasma sheet boundary layer" by G. Parks, et al. SO GEOPHYSICAL RESEARCH LETTERS LA English DT Editorial Material ID DISTRIBUTIONS; ELECTRON; MODEL; ISEE-1; EDGE; TAIL C1 Lockheed Martin Adv Technol Ctr, Palo Alto, CA 94304 USA. NOAA, Space Environm Lab, Boulder, CO 80303 USA. RP Fuselier, SA (reprint author), Lockheed Martin Adv Technol Ctr, Palo Alto, CA 94304 USA. NR 10 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 15 PY 1999 VL 26 IS 16 BP 2637 EP 2638 DI 10.1029/1999GL900575 PG 2 WC Geosciences, Multidisciplinary SC Geology GA 226GD UT WOS:000082011200058 ER PT J AU Liang, JK Huang, Q Santoro, A Wang, JL Yang, FM AF Liang, JK Huang, Q Santoro, A Wang, JL Yang, FM TI Magnetic structure and site occupancies in YFe11-xCoxTi (x=1,3,7,9) SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID NEUTRON-DIFFRACTION; ALLOYS AB The crystal and magnetic structures of the system YFe11-xCoxTi have been investigated by high-resolution neutron powder diffraction for the compositions x=1, 3, 7, and 9. All compounds have the ThMn12 type structure, with space group symmetry I4/mmm. The distribution of the atoms over the independent crystallographic sites was found to be significantly different from random, with a strong preference for Ti to be in the 8i site and Co in the 8j and 8f sites. This behavior can be explained in terms of the enthalpy of formation of binary alloys. The magnetic moments are parallel to the c axis for the compositions x=1, 3, 9, and lie in the a-b plane for x=7. No evidence of additional nuclear or magnetic phase transitions was observed for sample YFe4Co7Ti down to 20 K. (C) 1999 American Institute of Physics. [S0021-8979(99)00216-9]. C1 Chinese Acad Sci, Inst Phys, Beijing 100080, Peoples R China. Chinese Acad Sci, Ctr Condensed Matter Phys, Beijing 100080, Peoples R China. Natl Inst Stand & Technol, Ctr Neutron Ctr, Gaithersburg, MD 20899 USA. Univ Maryland, Dept Mat & Nucl Engn, College Pk, MD USA. RP Liang, JK (reprint author), Chinese Acad Sci, Inst Phys, POB 603, Beijing 100080, Peoples R China. NR 12 TC 10 Z9 12 U1 1 U2 4 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD AUG 15 PY 1999 VL 86 IS 4 BP 2155 EP 2160 DI 10.1063/1.371023 PG 6 WC Physics, Applied SC Physics GA 221HD UT WOS:000081720600057 ER PT J AU Koch, SE Clark, WL AF Koch, SE Clark, WL TI A nonclassical cold front observed during COPS-91: Frontal structure and the process of severe storm initiation SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID ATMOSPHERIC UNDULAR BORES; SEVERE WEATHER OUTBREAK; LOW-LEVEL STRUCTURE; SEA-BREEZE FRONT; DOPPLER RADAR; SQUALL LINE; ROCKY-MOUNTAINS; MESOSCALE CIRCULATIONS; NUMERICAL SIMULATIONS; MICROWAVE RADIOMETER AB This case study addresses the issue of gravity current and bore development at surface cold fronts, and the role of these phenomena in the generation of severe frontal convection. The event investigated occurred on 27 April 1991 during the Cooperative Oklahoma Profiler Studies 1991 field project. The development of a bore from a gravity current-like structure along a cold front, the subsequent propagation of the bore ahead of the front on a low-level inversion, and the process of severe thunderstorm development along the front are revealed by a dense network of remote sensing and other special observations. Evidence for the gravity current and bore is strengthened by comparisons made between the synthesized observations and theory. The bore developed after a nocturnal inversion, which acted as a waveguide, had become established. The bore and gravity current were both evident as "fine lines" in the radar reflectivity displays. A microscale envelope of enhanced water vapor with an embedded roll cloud, a strong vertical circulation, and a low-level microscale "jetlet" were associated with the bore. A pronounced "feeder flow" was present behind the gravity current, in association with a second vertical circulation, which was more elevated than the one associated with the bore. The jetlet provided an efficient wave-trapping mechanism for the bore, due to the combined effects of wind curvature on the Scorer parameter profile and mass convergence enhancement by the low-level shear. Effects of the bore and gravity current passage on the atmosphere were assessed by applying parcel displacement profiles derived from wind profiler analysis to an observed prebore sounding, and then to a computed postbore sounding. These calculations suggest that the strong bore-induced lifting was insufficient to trigger the storms; rather, it was the dual lifting provided by the bore and the gravity current that made it possible for low-level parcels to reach their level of free convection. These results confirm other recent findings that indicate that even though bores generated by gravity currents can produce strong lifting, this may be insufficient to trigger deep convection whenever the lifting is confined to too shallow a layer and/or is of insufficient duration. C1 N Carolina State Univ, Dept Marine Earth & Atmospher Sci, Raleigh, NC 27695 USA. NOAA, ERL, Aeron Lab, Boulder, CO 80303 USA. RP Koch, SE (reprint author), N Carolina State Univ, Dept Marine Earth & Atmospher Sci, Campus Box 8208, Raleigh, NC 27695 USA. NR 79 TC 38 Z9 39 U1 1 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 AUG 15 PY 1999 VL 56 IS 16 BP 2862 EP 2890 DI 10.1175/1520-0469(1999)056<2862:ANCFOD>2.0.CO;2 PG 29 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 230DW UT WOS:000082237400008 ER PT J AU Hsueh, CH Fuller, ER Langer, SA Carter, WC AF Hsueh, CH Fuller, ER Langer, SA Carter, WC TI Analytical and numerical analyses for two-dimensional stress transfer SO MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING LA English DT Article DE stress transfer; interface; composite; analytical modeling; numerical simulations ID FIBER PULL-OUT; CERAMIC COMPOSITES; ELLIPSOIDAL INCLUSIONS; MATRIX COMPOSITES; STRENGTH; FRACTURE AB Both analytical modeling and numerical simulations were performed to analyze the stress transfer in platelet-reinforced composites in a two-dimensional sense. In the two-dimensional model, an embedded elongated plate bonded to a matrix along its long edges was considered. The system was subjected to both tensile loading parallel to the plate's long edges and residual thermal stresses. The ends of the plate can be debonded from or bonded to the matrix during loading, and both cases were considered in the analysis. Good agreement was obtained between the present analytical and numerical solutions. However, better agreement between analytical and numerical models was obtained for the case of bonded ends than for debonded ends. (C) 1999 Elsevier Science S.A. All rights reserved. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Hsueh, CH (reprint author), Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RI Hsueh, Chun-Hway/G-1345-2011; Carter, W/K-2406-2012 NR 24 TC 30 Z9 31 U1 1 U2 3 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0921-5093 J9 MAT SCI ENG A-STRUCT JI Mater. Sci. Eng. A-Struct. Mater. Prop. Microstruct. Process. PD AUG 15 PY 1999 VL 268 IS 1-2 BP 1 EP 7 DI 10.1016/S0921-5093(99)00129-X PG 7 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA 211FK UT WOS:000081149700001 ER PT J AU Yildirim, T Kilic, C Ciraci, S Gehring, PM Neumann, DA Eaton, PE Emrick, T AF Yildirim, T Kilic, C Ciraci, S Gehring, PM Neumann, DA Eaton, PE Emrick, T TI Vibrations of the cubane molecule: inelastic neutron scattering study and theory SO CHEMICAL PHYSICS LETTERS LA English DT Article ID SOLID CUBANE; PHASE-TRANSITION; FORCE-FIELD; SPECTRA; NMR AB Cubane (C8H8) is an immensely strained molecule whose C-C-C bond angle is 90 degrees rather than 109.5 degrees as expected for sp(3) bonding of carbon. We have measured the intramolecular vibrational spectrum of cubane using inelastic neutron scattering. The neutron data are used to test the transferability of various phenomenological potentials and tight-binding models to this highly strained molecule. Unlike these models, first-principles calculations of the INS spectrum (both energy and intensity) agree well with the experimental data. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 NIST, Ctr Neutron Res, Gaithersburg, MD 20899 USA. Univ Maryland, College Pk, MD 20742 USA. Bilkent Univ, Dept Phys, TR-06533 Ankara, Turkey. Univ Chicago, Dept Chem, Chicago, IL 60637 USA. RP Yildirim, T (reprint author), NIST, Ctr Neutron Res, Gaithersburg, MD 20899 USA. RI yildirim, taner/A-1290-2009; Kilic, Cetin/E-1336-2011; OI Kilic, Cetin/0000-0003-2690-4940; Gehring, Peter/0000-0002-9236-2046 NR 32 TC 12 Z9 12 U1 0 U2 5 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 AUG 13 PY 1999 VL 309 IS 3-4 BP 234 EP 240 DI 10.1016/S0009-2614(99)00655-7 PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 227YH UT WOS:000082107200015 ER PT J AU Mildner, DFR AF Mildner, DFR TI Self-shielding for thick slabs in a converging neutron beam SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article DE converging neutron beam; highly absorbing samples; neutron focusing lens; neutron self-shielding AB We have previously given a correction to the neutron self-shielding for a thin slab to account for the increased average path length through the slab when irradiated in a converging neutron beam. This expression overstates the case for the self-shielding for a thick (or highly absorbing) slab. We give a better approximation to the increase in effective shielding correction for a slab placed in a converging neutron beam. It is negligible at large absorption mean free paths. (C) 1999 Elsevier Science B.V. All rights reserved. C1 US Dept Commerce, Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Mildner, DFR (reprint author), US Dept Commerce, Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NR 2 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD AUG 11 PY 1999 VL 432 IS 2-3 BP 399 EP 402 DI 10.1016/S0168-9002(99)00256-9 PG 4 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 226RL UT WOS:000082035200021 ER PT J AU Fox, CG Dziak, RP AF Fox, CG Dziak, RP TI Internal deformation of the Gorda Plate observed by hydroacoustic monitoring SO JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH LA English DT Article ID COUPLED SUBDUCTION ZONES; MOMENT TENSOR SOLUTIONS; DE-FUCA RIDGE; SOUTHERN CALIFORNIA; STATIC STRESS; INTRAPLATE EARTHQUAKES; HYDROPHONE ARRAYS; LANDER EARTHQUAKE; CAPE-MENDOCINO; SEISMICITY AB On August 29, 1991, the National Oceanic and Atmospheric Administration VENTS Program began monitoring the northeast Pacific Ocean plate boundaries using continuously recorded data from the U.S. Navy's Sound Surveillance System (SOSUS) hydrophone arrays. Routine detection and location of small (2.4 less than or equal to M less than or equal to 3.5) earthquakes revealed a NNE-SSW trending band of seismicity through the center of the Gorda Plate. The majority of the earthquakes in the band were not detected by land-based seismic networks. This band of microearthquakes was active from the initiation of SOSUS monitoring in August 1991 through July 1992, at a rate of similar to 20 events per week. Since August 1992, however, the activity has effectively ceased. Some of the microearthquakes in the band are likely aftershocks to three large (M-W > 6) mid Gorda Plate earthquakes that occurred 1-2 months prior to the beginning of SOSUS monitoring. The hydroacoustically detected events in the band, however, do not occur in the proximity of the M-W > 6 events, and the activity level increased several months afterward, suggesting the microseismicity band represents a more general pattern of deformation within the Gorda Plate. The cessation of the midplate activity follows the occurrence of a large earthquake sequence in the adjacent Cascadia Subduction Zone in April 1992. It is proposed that the band of microseismicity and the three large midplate events reflect an accumulation of stress in the Gorda Plate, with the eventual termination of this pattern due to stress reduction associated with movement in the adjacent subduction zone. Stress field modeling of the region yields results consistent with this interpretation. C1 Oregon State Univ, Hatfield Marine Sci Ctr, Pacific Marine Environm Lab, NOAA, Newport, OR 97365 USA. Oregon State Univ, Hatfield Marine Sci Ctr, NOAA, Cooperat Inst Marine Resources Studies, Newport, OR 97365 USA. RP Fox, CG (reprint author), Oregon State Univ, Hatfield Marine Sci Ctr, Pacific Marine Environm Lab, NOAA, 2115 SE OSU Dr, Newport, OR 97365 USA. EM dziak@pmel.noaa.gov; fox@pmel.noaa.gov NR 46 TC 18 Z9 18 U1 1 U2 1 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 10 PY 1999 VL 104 IS B8 BP 17603 EP 17615 DI 10.1029/1999JB900104 PG 13 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 224LL UT WOS:000081900500004 ER PT J AU Lefebvre, KK Lee, JH Balsara, NP Hammouda, B Krishnamoorti, R Kumar, S AF Lefebvre, KK Lee, JH Balsara, NP Hammouda, B Krishnamoorti, R Kumar, S TI Relationship between internal energy and volume change of mixing in pressurized polymer blends SO MACROMOLECULES LA English DT Article ID POLYSTYRENE POLYVINYL METHYL-ETHER); ANGLE NEUTRON-SCATTERING; BLOCK-COPOLYMER; TEMPERATURE; MIXTURES; COMPRESSIBILITY; FLUCTUATIONS; PREDICTIONS; DEPENDENCE; PARAMETER C1 Polytech Univ, Dept Chem Engn Chem & Mat Sci, Brooklyn, NY 11201 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Univ Houston, Dept Chem Engn, Houston, TX 77204 USA. Penn State Univ, Dept Mat Sci & Engn, University Pk, PA 16802 USA. RP Balsara, NP (reprint author), Polytech Univ, Dept Chem Engn Chem & Mat Sci, 6 Metrotech Ctr, Brooklyn, NY 11201 USA. RI Krishnamoorti, Ramanan/F-7914-2011 OI Krishnamoorti, Ramanan/0000-0001-5831-502X NR 22 TC 22 Z9 23 U1 0 U2 9 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0024-9297 J9 MACROMOLECULES JI Macromolecules PD AUG 10 PY 1999 VL 32 IS 16 BP 5460 EP 5462 PG 3 WC Polymer Science SC Polymer Science GA 227BL UT WOS:000082058100043 ER PT J AU Davico, GE Schwartz, RL Ramond, TM Lineberger, WC AF Davico, GE Schwartz, RL Ramond, TM Lineberger, WC TI An experimental study of the low-lying electronic states of WO2 SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID PHOTOELECTRON-SPECTROSCOPY; INFRARED-SPECTRA; MOLYBDENUM; TUNGSTEN; OXIDES; DIOXYGEN; PEROXO AB The 364 nm negative ion photoelectron spectrum of WO2- is obtained. The spectrum reveals that four different electronic states are accessed in the neutral molecule following electron detachment. From the rich vibrational structure the vibrational frequencies of the bending and/or symmetric stretching vibrations are measured. The electron affinity is determined to be 1.998(10) - 0.040k eV, where k = 0, 1, or 2. Theoretical calculations have been carried out to determine the geometries, energies, and frequencies of the anion and neutral molecules. These are utilized to generate a simulation of the experimental spectrum. The excellent agreement between the spectrum and the simulation indicates that the changes in geometries upon detachment are well predicted by the theoretical method employed, at least for the two lowest electronic states. In addition, polarization studies enable us to determine the asymmetry parameters for each state and thus confirm the assignments of the electronic states. C1 Univ Colorado, JILA, Boulder, CO 80309 USA. Natl Inst Stand & Technol, Boulder, CO 80309 USA. Univ Colorado, Dept Biochem & Chem, Boulder, CO 80309 USA. RP Lineberger, WC (reprint author), Univ Colorado, JILA, Boulder, CO 80309 USA. NR 21 TC 32 Z9 32 U1 0 U2 9 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 AUG 5 PY 1999 VL 103 IS 31 BP 6167 EP 6172 DI 10.1021/jp9911752 PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 227UU UT WOS:000082099000016 ER PT J AU Atkinson, DB Hudgens, JW Orr-Ewing, AJ AF Atkinson, DB Hudgens, JW Orr-Ewing, AJ TI Kinetic studies of the reactions of IO radicals determined by cavity ring-down spectroscopy SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID ABSORPTION CROSS-SECTIONS; SELF-REACTION; RATE COEFFICIENTS; RATE-CONSTANT; LIF DETECTION; GAS-PHASE; PHOTOLYSIS; IODINE; O(P-3); BRO AB We demonstrate the application of cavity ring-down spectroscopy (CRDS) to the measurement of concentrations of IO radical and of reaction rate coefficients for the reaction systems, IO + IO and IO + NO, using the source reaction, O(P-3) + CSI. By monitoring IO radicals, we obtain the 295 K rate coefficients, k(O + CSI --> IO + CF3) = (5.8 +/- 1.5) x 10(-12) cm(3) molec(-1) s(-1); k(IO + IO) = (1.0 +/- 0.3) x 10(-10) cm(3) molec(-1) s(-1) and k(IO + NO) = (1.9 +/- 0.5) x 10(-12) cm(3) molec(-1) s(-1) at the pressures of 1250 Pa (9.4 Torr) and 4000 Pa (30.1 Torr). For the IO A (2)Pi(3/2) - X (2)Pi(3/2) (2, 0) bandhead at 445.04 nm we have determined an absorption cross-section, sigma = (7.3 +/- 0.7) x 10(-17) cm(2). Error limits indicate the confidence of two standard deviations and propagate the uncertainty in the absorption cross-section. C1 NIST, Phys & Chem Properties Div, Gaithersburg, MD 20899 USA. Univ Bristol, Sch Chem, Bristol BS8 1TS, Avon, England. RP Hudgens, JW (reprint author), NIST, Phys & Chem Properties Div, Gaithersburg, MD 20899 USA. OI Orr-Ewing, Andrew/0000-0001-5551-9609 NR 59 TC 47 Z9 47 U1 0 U2 8 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 AUG 5 PY 1999 VL 103 IS 31 BP 6173 EP 6180 DI 10.1021/jp9902497 PG 8 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 227UU UT WOS:000082099000017 ER PT J AU Marquez, M Mari, F Gonzalez, CA AF Marquez, M Mari, F Gonzalez, CA TI Ab initio study of the reactions between a series of substituted singlet nitrenium ions and water SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID LASER FLASH-PHOTOLYSIS; QUADRATIC CONFIGURATION-INTERACTION; ARYLNITRENIUM IONS; YLIDE FORMATION; GAS-PHASE; DIARYLNITRENIUM IONS; ELECTRON CORRELATION; STABLE CARBOCATIONS; TRIPLET GAP; ENERGY AB Highly correlated ab initio molecular orbital calculations have been used to study the energetics and mechanisms governing the reactions of a series of substituted singlet nitrenium ions ((1)[R-N-H](+), R = H, Cl, F, CN, and Me) with water in gas phase and in solution. It was found that, in gas phase and in solution, the nitrenium ions react in a barrierless fashion to produce an intermediate [HNR-OH2](+), which in turn undergoes a 1,2-hydrogen shift to produce the corresponding protonated hydroxylamine [RNH2OH](+). Results obtained at the QCISD(T)/6-311++G**//QCISD/6-311++G** indicate that in the gas phase, the intermediates are located between 27.7 and 339.6 kJ/mol below the reactants depending upon the substituent on the nitrenium ion. The transition states are located between 93.1 and 141.9 kJ/mol above the intermediates depending upon the substituent in question. Electrostatic interactions with the solvent increases the intrinsic barrier of the process, as it lowers the relative energy of the intermediates (and reactants) with respect to the transition state. It is also found that the reaction of water with the methyl nitrenium ion inhibits the decomposition of this species in gas phase. The effects of the substituent, the solvent, and the levels of theory employed on the reaction paths are discussed in detail. In addition, the reaction of singlet nitrenium ion with two water molecules is also studied and the results are discussed in the context of the importance of the explicit treatment of the solvent in the determination of the energetics and mechanisms of these processes. C1 Florida Atlantic Univ, Dept Chem & Biochem, Boca Raton, FL 33431 USA. Florida Atlantic Univ, Ctr Mol Biosci & Biotechnol, Boca Raton, FL 33431 USA. Yale Univ, Dept Chem, New Haven, CT 06520 USA. Natl Inst Stand & Technol, Phys & Chem Properties Div, Gaithersburg, MD 20899 USA. RP Mari, F (reprint author), Florida Atlantic Univ, Dept Chem & Biochem, 777 Glades Rd, Boca Raton, FL 33431 USA. NR 77 TC 20 Z9 20 U1 0 U2 2 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 AUG 5 PY 1999 VL 103 IS 31 BP 6191 EP 6199 DI 10.1021/jp983189y PG 9 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 227UU UT WOS:000082099000020 ER PT J AU Toggweiler, JR AF Toggweiler, JR TI Oceanography - An ultimate limiting nutrient SO NATURE LA English DT Editorial Material ID NITROGEN-FIXATION; PACIFIC-OCEAN; WORLD OCEAN; CO2 C1 Princeton Univ, NOAA, Geophys Fluid Dynam Lab, Princeton, NJ 08542 USA. RP Toggweiler, JR (reprint author), Princeton Univ, NOAA, Geophys Fluid Dynam Lab, POB 308, Princeton, NJ 08542 USA. NR 10 TC 20 Z9 27 U1 1 U2 12 PU MACMILLAN MAGAZINES LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD AUG 5 PY 1999 VL 400 IS 6744 BP 511 EP 512 DI 10.1038/22892 PG 2 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 223RT UT WOS:000081854800028 ER PT J AU Sari, N Holden, MJ Mayhew, MP Vilker, VL Coxon, B AF Sari, N Holden, MJ Mayhew, MP Vilker, VL Coxon, B TI Comparison of backbone dynamics of oxidized and reduced putidaredoxin by N-15 NMR relaxation measurements SO BIOCHEMISTRY LA English DT Article ID MAGNETIC-RESONANCE RELAXATION; ESCHERICHIA-COLI THIOREDOXIN; AMIDE PROTON-EXCHANGE; MODEL-FREE APPROACH; C-TERMINAL REGION; ELECTRON-TRANSFER; CYTOCHROME B(5); HYDROGEN-EXCHANGE; SPECTROSCOPY; BINDING AB The backbone dynamics of uniformly N-15-labeled reduced and oxidized putidaredoxin (Pdx) have been studied by 2D N-15 NMR relaxation measurements. N-15 T-1 and T-2 values and H-1-N-15 NOEs have been measured for the diamagnetic region of the protein. These data were analyzed by using a model-free dynamics formalism to determine the generalized order parameters (S-2), the effective correlation time for internal motions (tau(e)), and the N-15 exchange broadening contributions (R-ex) for each residue, as well as the overall correlation time (tau(m)). Order parameters for the reduced Pdx are generally higher than for the oxidized Pdx, and there is increased mobility on the microsecond to millisecond time scale for the oxidized Pdx, in comparison with the reduced Pdx. These results clearly indicate that the oxidized protein exhibits higher mobility than the reduced one, which is in agreement with the recently published redox-dependent dynamics studied by amide proton exchange. In addition, we observed very high T-1/T-2 ratios for residues 33 and 34, giving rise to a large R-ex contribution. Residue 34 is believed to be involved in the binding of Pdx to cytochrome P450cam (CYP101). The differences in the backbone dynamics are discussed in relation to the oxidation states of Pdx, and their impact on electron transfer. The entropy change occurring on oxidation of reduced Pdx has been calculated from the order parameters of the two forms. C1 Natl Inst Stand & Technol, Div Biotechnol, Gaithersburg, MD 20899 USA. RP Coxon, B (reprint author), Natl Inst Stand & Technol, Div Biotechnol, 100 Bur Dr,Stop 8311, Gaithersburg, MD 20899 USA. NR 42 TC 27 Z9 27 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0006-2960 J9 BIOCHEMISTRY-US JI Biochemistry PD AUG 3 PY 1999 VL 38 IS 31 BP 9862 EP 9871 DI 10.1021/bi9906423 PG 10 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 226HG UT WOS:000082014100009 PM 10433692 ER PT J AU Banford, HM Bermingham, E Collette, BB McCafferty, SS AF Banford, HM Bermingham, E Collette, BB McCafferty, SS TI Phylogenetic systematics of the Scomberomorus regalis (Teleostei : Scombridae) species group: Molecules, morphology and biogeography of Spanish mackerels SO COPEIA LA English DT Article ID MITOCHONDRIAL-DNA EVOLUTION; EASTERN PACIFIC; UNITED-STATES; ATP SYNTHASE; NUCLEAR; PANAMA; AMPLIFICATION; ISTHMUS; MODEL; DIVERGENCE AB Phylogenetic and historical biogeographic hypotheses were explored and inferred for the Scomberomorus regalis species group, composed of five New World species (S, regalis, S. brasiliensis, S. maculatus, S. concolor, and S. sierra) and the eastern Atlantic S. tritor, in testing the generalization of Rosen's eastern Pacific/eastern Atlantic track hypothesis. The Indo-West Pacific S. guttatus and Atlantic S. cavalla served as outgroups. The entire ATP synthase 8 [ATPase 8; 168 base pairs (bp)] and 6 (ATPase 6; 684 bp), and NADH ubiquinone oxidoreductase subunit 2 (ND2; 1047 bp) mitochondrial genes, and an approximately 400-bp portion of the nuclear encoded Aldolase exon 5/intron 5 were sequenced. The monophyly of the S. regalis species group was fully supported, with the eastern Atlantic S. tritor basal to the New World taxa as predicted from the eastern Atlantic/eastern Pacific generalized biogeographic track. surprisingly, no differences were observed between the mitochondrial genomes of S, regalis and S. maculatus. However nuclear DNA and morphological characters confirm the species status of these two taxa; leading us to posit the introgressive loss of the S, maculatus mtDNA genome following hybridization with S. regalis. chronological estimates were applied to the phylogenetic topology combining geologic dates for putative vicariant events with molecular distance values. These estimates indicate a pre-isthmian divergence for the western Atlantic S. maculatus, followed by divergence of the common ancestors of the western Atlantic (S. brasiliensis and S. regalis) and eastern Pacific (S. concolor and S. sierra) species resulting from the rise of the Isthmus of Panama and closure of associated seaways. C1 Smithsonian Trop Res Inst, Balboa, Panama. Smithsonian Trop Res Inst, Unit 0948, APO, AA 34002 USA. Virginia Inst Marine Sci, Gloucester Point, VA 23062 USA. Natl Museum Nat Hist, Natl Systemat Lab, Natl Marine Fisheries Serv, Washington, DC 20560 USA. RP Banford, HM (reprint author), Smithsonian Trop Res Inst, Apartado 2072, Balboa, Panama. NR 68 TC 36 Z9 36 U1 0 U2 2 PU AMER SOC ICHTHYOLOGISTS HERPETOLOGISTS PI CHARLESTON PA UNIV CHARLESTON, GRICE MARINE LABORATORY, 205 FORT JOHNSON RD, CHARLESTON, SC 29412 USA SN 0045-8511 J9 COPEIA JI Copeia PD AUG 2 PY 1999 IS 3 BP 596 EP 613 PG 18 WC Zoology SC Zoology GA 227HR UT WOS:000082075500005 ER PT J AU Carlson, JK Cortes, E Johnson, AG AF Carlson, JK Cortes, E Johnson, AG TI Age and growth of the blacknose shark, Carcharhinus acronotus, in the eastern Gulf of Mexico SO COPEIA LA English DT Article ID ATLANTIC SHARPNOSE SHARK; BONNETHEAD SHARK; SPHYRNA-TIBURO; RHIZOPRIONODON-TERRAENOVAE; NORTHWESTERN GULF; SPINY DOGFISH; 2 POPULATIONS; LIFE-HISTORY; LENGTH AB Age and growth of the blacknose shark, Carcharhinus acronotus, from the eastern Gulf of Mexico was estimated by counting bands on the vertebral centra from 123 individuals. Back-calculated von Bertalanffy growth functions were constructed for populations in northwest Florida and Tampa Bay, Florida. Von Bertalanffy growth function parameters for males in northwest Florida (L-infinity = 963.1 mm FL, K = 0.59, t(0) = -0.754 yr) were significantly different from those in Tampa Bay (L-infinity = 801.0 mm FL, K = 0.771, t(0) = -0.797 yr), as were those for females (L-infinity = 1136.5 mm FL, K = 0.352, t(0) = -1.212 yr in northwest Florida; L-infinity = 1241.3 mm FL, K = 0.237, t(0) = -1.536 yr in Tampa Bay). Theoretical longevity, estimated as the age at which 95% of L-infinity is reached, varied from age 10-16 yr for females and 4.5-9.0 yr for males, depending on geographic area. The oldest sharks aged were 4.5+ yr. Centrum edge and marginal increment analyses lent support to the hypothesis that narrow dark bands are formed during winter months. Length-frequency analysis verified back-calculated size at ages 0, 1, and 2. The growth dynamics of blacknose sharks are similar to those of other relatively small, fast-growing, short-lived species of sharks. C1 NOAA, Natl Marine Fisheries Serv, SW Fisheries Sci Ctr, Panama City, FL 32408 USA. RP Carlson, JK (reprint author), NOAA, Natl Marine Fisheries Serv, SW Fisheries Sci Ctr, 3500 Delwood Beach Rd, Panama City, FL 32408 USA. RI Cortes, Enric/H-2700-2013 NR 32 TC 30 Z9 32 U1 2 U2 6 PU AMER SOC ICHTHYOLOGISTS HERPETOLOGISTS PI CHARLESTON PA UNIV CHARLESTON, GRICE MARINE LABORATORY, 205 FORT JOHNSON RD, CHARLESTON, SC 29412 USA SN 0045-8511 J9 COPEIA JI Copeia PD AUG 2 PY 1999 IS 3 BP 684 EP 691 PG 8 WC Zoology SC Zoology GA 227HR UT WOS:000082075500012 ER PT J AU Zong, W Dunn, GH Djuric, N Larsson, M Greene, CH Al-Khalili, A Neau, A Derkatch, AM Vikor, L Shi, W Le Padellec, A Rosen, S Danared, H Ugglas, MA AF Zong, W Dunn, GH Djuric, N Larsson, M Greene, CH Al-Khalili, A Neau, A Derkatch, AM Vikor, L Shi, W Le Padellec, A Rosen, S Danared, H Ugglas, MA TI Resonant ion pair formation in electron collisions with ground state molecular ions SO PHYSICAL REVIEW LETTERS LA English DT Article ID DISSOCIATIVE RECOMBINATION; CROSS-SECTIONS AB Resonant ion pair formation from collisions of electrons with ground state diatomic molecular ions has been observed and absolute cross sections measured. The cross section for HD+ is characterized by an abrupt threshold at 1.9 eV and 14 resolved peaks in the range of energies 0 less than or equal to E less than or equal to 14 eV. The dominant mechanism responsible fbr the structures appears to be resonant capture and stabilization, modified by two-channel quantum interference. Data on HF+ show structure correlated with photoionization of HF and with dissociative recombination of electrons with this ion. C1 Univ Colorado, JILA, Boulder, CO 80309 USA. Univ Colorado, Dept Phys, Boulder, CO 80309 USA. Natl Inst Stand & Technol, Boulder, CO 80309 USA. Univ Stockholm, Dept Mol Phys, S-11385 Stockholm, Sweden. Univ Catholique Louvain, Inst Phys, B-1348 Louvain, Belgium. Manne Siegbahn Lab, S-10405 Stockholm, Sweden. RP Zong, W (reprint author), Univ Colorado, JILA, Boulder, CO 80309 USA. RI Greene, Chris/C-3821-2011 OI Greene, Chris/0000-0002-2096-6385 NR 18 TC 26 Z9 26 U1 0 U2 1 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 AUG 2 PY 1999 VL 83 IS 5 BP 951 EP 954 DI 10.1103/PhysRevLett.83.951 PG 4 WC Physics, Multidisciplinary SC Physics GA 223BT UT WOS:000081820400016 ER PT J AU Branning, D Grice, WP Erdmann, R Walmsley, IA AF Branning, D Grice, WP Erdmann, R Walmsley, IA TI Engineering the indistinguishability and entanglement of two photons SO PHYSICAL REVIEW LETTERS LA English DT Article ID PARAMETRIC DOWN-CONVERSION; INDUCED COHERENCE; INDUCED EMISSION; 2 PHOTONS; QUANTUM; INTERFERENCE; INFORMATION; DISTINGUISHABILITY; TELEPORTATION; CRYPTOGRAPHY AB We present a novel interferometric technique for suppressing distinguishing information in the spacetime component of the state vector of an entangled pair of photons by providing two indistinguishable ways for each photon to occupy any given space-time mode. We demonstrate this method by using spontaneous parametric down-conversion to generate a pair of photons in the state with the least distinguishing information consistent with the set of modes available. The technique also allows the preparation of the two photons in a highly entangled space-time state provided certain criteria are met. C1 Univ Rochester, Dept Phys & Astron, Rochester, NY 14627 USA. Univ Rochester, Inst Opt, Rochester, NY 14627 USA. RP Branning, D (reprint author), NIST, 100 Bur Dr MS 8441, Gaithersburg, MD 20899 USA. RI Grice, Warren/L-8466-2013; OI Grice, Warren/0000-0003-4266-4692 NR 19 TC 56 Z9 57 U1 0 U2 9 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 2 PY 1999 VL 83 IS 5 BP 955 EP 958 DI 10.1103/PhysRevLett.83.955 PG 4 WC Physics, Multidisciplinary SC Physics GA 223BT UT WOS:000081820400017 ER PT J AU Jordan, CE Stranick, SJ Cavanagh, RR Richter, LJ Chase, DB AF Jordan, CE Stranick, SJ Cavanagh, RR Richter, LJ Chase, DB TI Near-field scanning optical microscopy incorporating Raman scattering for vibrational mode contrast SO SURFACE SCIENCE LA English DT Article; Proceedings Paper CT 14th International Vacuum Congress/10th International Conference on Solid Surfaces/5th International Conference on Nanometre-Scale Science and Technology/10th International Conference on Quantitative Surface Analysis CY AUG 31-SEP 04, 1998 CL BIRMINGHAM, ENGLAND SP British Vacuum Council, Inst Phys, Int Union Vacuum Sci Tech & Applicat DE diamond; light scattering; Raman scattering spectroscopy ID SPECTROSCOPY; SCALE; PROBE AB Near-field scanning optical microscopy offers the ability to combine a broad range of spectral contrast features with spatial resolution that is an order of magnitude better than that set by the diffraction limit of the probe light. For many chemical problems, it would be advantageous to use vibrational spectroscopy as the optical contrast mechanism. This realization of optical contrast would enable nanometer scale identification of changes in chemical composition as a function of position and/or time. A leading candidate for this chemical imaging approach is Raman scattering. Ln this paper a comparison of transmitted and reflected signals will be made as a function of probe-to-sample separation, thus discriminating between bulk and near-field contributions of the detected signal. Also, the decay of the Raman intensity as a function of probe-to-sample separation will be used to show the sensitivity to local field effects. (C) 1999 Elsevier Science B.V. All rights reserved. C1 NIST, Surface & Microanal Sci Div, Gaithersburg, MD 20899 USA. Dupont Co, Cent Res & Dev, Expt Stn, Wilmington, DE 19880 USA. RP Stranick, SJ (reprint author), NIST, Surface & Microanal Sci Div, Gaithersburg, MD 20899 USA. EM stephan.stranick@nist.gov RI Richter, Lee/N-7730-2016 OI Richter, Lee/0000-0002-9433-3724 NR 20 TC 14 Z9 14 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD AUG 2 PY 1999 VL 433 BP 48 EP 52 DI 10.1016/S0039-6028(99)00069-2 PG 5 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA 230DA UT WOS:000082235500009 ER PT J AU Tang, LY Shen, CM Liu, KB Overpeck, JT AF Tang, LY Shen, CM Liu, KB Overpeck, JT TI New high-resolution pollen records from two lakes in Xizang (Tibet) SO ACTA BOTANICA SINICA LA Chinese DT Article DE South Asia monsoon; pollen records; Southeast Tibet; paleovegetation and paleoclimate ID ORBITAL PARAMETERS; MONSOON CLIMATE; HOLOCENE; CHINA AB Studies on the pollen from cores of Lake Hidden (29 degrees 48, 77'N, 92 degrees 22. 37'E) and Ren Co (30 degrees 43.97'N, 96 degrees 40. 97' E) in Southeast Xizang (Tibet) showed climatic changes and the evolution of vegetation since the Last Glacial Maximum (LGM), Before 16 ka BP pollen assemblages were dominated by Chenopodiaceae (20% similar to 50%) and Artemisia (10% similar to 30%) and pollen influx values were very low from Lake Ren Co in Basu county. The vegetation around the lake was probably a desert-steppe during the LGM, The data also suggest that the climate in the Basu area was cold and dry during the LGM and the last glacial time. The mean annual temperature was probably 4 similar to 6 degrees C colder than the present, and the mean annual precipitation was only 250 mm, about 40% of the present. The Southwest monsoon became stronger from 12 ka BP to 6 ka BP reaching its acme by 7 ka BP, but weakened gradually from 5 ka BP to the present. The paleovegetation was dominantly forest or forest-meadow around Lake Hidden and Ren Co during the 9.2 similar to 5 ka BP. The mean temperature in January nas probably 2 similar to 3 degrees C higher than the present, and the mean annual precipitation was 100 mm more than the present. The timing of vegetational and climatic changes based on pollen records generally supports the results of global climatic-model experiments that predict a strengthened monsoon system during the early to middle Holocene followed by a weakened monsoon system. C1 Chinese Acad Sci, Nanjing Inst Geol & Paleontol, Nanjing 210008, Peoples R China. Louisiana State Univ, Dept Geog & Anthropol, Baton Rouge, LA 70803 USA. NOAA, Natl Geophys Data Ctr, Boulder, CO 80303 USA. RP Tang, LY (reprint author), Chinese Acad Sci, Nanjing Inst Geol & Paleontol, Nanjing 210008, Peoples R China. RI Liu, Kam-biu/B-4966-2012; Shen, Caiming/F-5687-2012 OI Liu, Kam-biu/0000-0002-0038-2198; Shen, Caiming/0000-0002-8126-8775 NR 21 TC 20 Z9 23 U1 2 U2 3 PU SCIENCE PRESS PI BEIJING PA 16 DONGHUANGCHENGGEN NORTH ST, BEIJING 100717, PEOPLES R CHINA SN 0577-7496 J9 ACTA BOT SIN JI Acta Bot. Sin. PD AUG PY 1999 VL 41 IS 8 BP 896 EP 902 PG 7 WC Biochemistry & Molecular Biology; Plant Sciences SC Biochemistry & Molecular Biology; Plant Sciences GA 233YP UT WOS:000082455000021 ER PT J AU Alers, GA AF Alers, GA TI Noncontacting electromagnetic and magnetostrictive transducers: Their unique features and applications SO ACTA PHYSICA SINICA-OVERSEAS EDITION LA English DT Article AB Noncontacting techniques for generating and receiving ultrasonic waves in solids are useful for industrial applications because they can be used in environments that are too harsh for conventional piezoelectric transducers. This paper will emphasize electromagnetic techniques in which a combination of static and dynamic magnetic fields are applied to conducting media in order to excite and detect ultrasonic waves by electromagnetic induction across a small gap. Besides being couplant free, the transducers are valuable as sources for a wider variety of wave types than are available to piezoelectric transducers. C1 Natl Inst Stand & Technol, Boulder, CO 80303 USA. RP Alers, GA (reprint author), Natl Inst Stand & Technol, 325 Broadway, Boulder, CO 80303 USA. NR 14 TC 1 Z9 1 U1 0 U2 1 PU GORDON BREACH SCI PUBL LTD PI READING PA C/O STBS LTD, PO BOX 90, READING RG1 8JL, BERKS, ENGLAND SN 1004-423X J9 ACTA PHYS SIN-OV ED JI Acta Phys. Sin.-Overseas Ed. PD AUG PY 1999 VL 8 SU S BP S9 EP S15 PG 7 WC Physics, Multidisciplinary SC Physics GA 258HN UT WOS:000083833200003 ER PT J AU Blessing, GV Fick, SE Hsu, NN Slotwinski, JA Xiang, D AF Blessing, GV Fick, SE Hsu, NN Slotwinski, JA Xiang, D TI Ultrasonic research and applications in the NIST Manufacturing Engineering Laboratory SO ACTA PHYSICA SINICA-OVERSEAS EDITION LA English DT Article AB The Ultrasonics Group in the NIST Manufacturing Engineering Laboratory performs research, develops standards, and offers calibration services in support of U.S. industry. Pulsed ultrasonic and acoustic emission techniques are pursued for application to materials nondestructive testing, medical diagnostics, and insitu sensing of manufacturing processes. Associated analytic studies are made of the generation, propagation, and detection of ultrasonic pulses in liquids and solids. In this paper two areas of recent experimental research are summarized: (1) the development and application of a large aperture lensless line-focus transducer, and (2) the measurement of nonlinear wave propagation effects which are present in industrial ultrasonic nondestructive testing. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Blessing, GV (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NR 13 TC 0 Z9 0 U1 0 U2 0 PU GORDON BREACH SCI PUBL LTD PI READING PA C/O STBS LTD, PO BOX 90, READING RG1 8JL, BERKS, ENGLAND SN 1004-423X J9 ACTA PHYS SIN-OV ED JI Acta Phys. Sin.-Overseas Ed. PD AUG PY 1999 VL 8 SU S BP S16 EP S21 PG 6 WC Physics, Multidisciplinary SC Physics GA 258HN UT WOS:000083833200004 ER PT J AU DeLorenzo, ME Lauth, J Pennington, PL Scott, GI Ross, PE AF DeLorenzo, ME Lauth, J Pennington, PL Scott, GI Ross, PE TI Atrazine effects on the microbial food web in tidal creek mesocosms SO AQUATIC TOXICOLOGY LA English DT Article DE atrazine; tidal creek; mesocosm; microbial food web ID MISSISSIPPI RIVER; UNITED-STATES; HERBICIDES; COMMUNITIES; WATER; FATE; SEA AB Atrazine effects on the microbial food web were assessed in mesocosms designed to simulate a southeastern tidal creek ecosystem. The test chambers simulate the major features unique to estuarine systems, such as tidal flow and salinity changes. Microbial communities were colonized on artificial substrates and analyzed for productivity, biomass, and community composition. Atrazine was found to reduce chlorophyll rr. phototrophic carbon assimilation and phototrophic biovolume in the 40 and 160 mu g l(-1) treatments. Significant reductions in phototrophic variables occurred within 24 h of pesticide exposure and no recovery was detected after 9 days. Dissolved oxygen content in the mesocosms was not significantly affected by atrazine. Atrazine induced changes in composition of the algal community. Most taxa were reduced in abundance by atrazine exposure; however, cyanobacterial taxa generally became more abundant. Bacterial abundance was significantly elevated in the highest dose after 24 h, but decreased in a dose-response manner after 45 h. There was no significant effect on small ciliates; however, large ciliates and small flagellates increased significantly in number after 48 h and remained elevated after 9 days. Atrazine at 160 mu g l(-1) significantly reduced large flagellate density throughout the experiment. These results suggest that exposure of the estuarine microbial food web to agricultural pesticides can lead to both functional and structural changes, which may potentially impact higher trophic levels. (C) 1999 Elsevier Science B.V. All rights reserved. C1 NOAA, US Dept Commerce, Natl Ocean Serv, Ctr Coastal Environm Hlth & Biomol Res, Charleston, SC 29412 USA. Virginia Polytech Inst & State Univ, Dept Biol, Blacksburg, VA 24061 USA. Colorado Sch Mines, Environm Sci & Engn Div, Golden, CO 80401 USA. RP DeLorenzo, ME (reprint author), NOAA, US Dept Commerce, Natl Ocean Serv, Ctr Coastal Environm Hlth & Biomol Res, 219 Ft Johnson Rd, Charleston, SC 29412 USA. NR 34 TC 25 Z9 27 U1 0 U2 9 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0166-445X J9 AQUAT TOXICOL JI Aquat. Toxicol. PD AUG PY 1999 VL 46 IS 3-4 BP 241 EP 251 DI 10.1016/S0166-445X(98)00132-5 PG 11 WC Marine & Freshwater Biology; Toxicology SC Marine & Freshwater Biology; Toxicology GA 226TK UT WOS:000082037700007 ER PT J AU Ylitalo, GM Buzitis, J Krahn, MM AF Ylitalo, GM Buzitis, J Krahn, MM TI Analyses of tissues of eight marine species from Atlantic and Pacific coasts for dioxin-like chlorobiphenyls (CBs) and total CBs SO ARCHIVES OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY LA English DT Article ID POLYCHLORINATED BIPHENYL CONGENERS; MULTIDIMENSIONAL GAS-CHROMATOGRAPHY; ELECTRON-CAPTURE DETECTION; TOXIC EQUIVALENCY FACTORS; DIBENZO-P-DIOXINS; MONO-ORTHO; TOXICOLOGICAL SIGNIFICANCE; ENVIRONMENTAL OCCURRENCE; POTENTIAL TOXICITY; FISH AB Eight commercially and recreationally important marine species were collected in 1993 and 1994 from several Atlantic and Pacific coastal regions of the contiguous United States. Approximately 700 edible tissue samples (e.g., whole body of mussel, crustacean muscle and hepatopancreas, and fish muscle) were analyzed for dioxin-like chlorobiphenyls (CBs) and other selected CB congeners using a rapid high-performance liquid chromatography photodiode array detection method (HPLC/PDA). Total CBs and toxic equivalents (TEQs) of dioxin-like CBs were also determined. The most abundant congeners measured in these tissues were the moderately chlorinated CBs (e.g., CB 138, 153), with mean concentrations ranging from below the limits of detection (approximately 0.2 ng/g) to 1,500 ng/g, wet weight. Certain dioxin-like CBs (e.g., CBs 77, 105, 118, 126) were also found in several of these samples (mean concentrations ranging from below the limits of detection [approximately 0.4 ng/g] to 680 ng/g). Similar to previous studies, the majority of seafood tissues contained total CB concentrations that were below the U.S. Food and Drug Administration's (FDA) tolerance limit for CBs of 2,000 ng/g, wet weight (2.0 ppm). Furthermore, the majority of samples that contained CB levels below the FDA CB tolerance limit also had CB TEQs that were lower than the FDA's advisory level for TCDD (25 ppt or 25 pg/g, wet weight) in fish from the Great Lakes, which is used in evaluating CB TEQs. Several crustacean hepatopancreas samples collected from certain Atlantic and Pacific urban sites (e.g., Dungeness crab from Elliott Bay in Puget Sound, WA, American lobster from Deer Island in Boston Harbor, MA), however, did contain total CB and CB TEQs that exceeded the FDA CB tolerance and TCDD advisory limits. Mono-ortho- (e.g., CBs 118, 105) and non-ortho-substituted congeners (e.g., CBs 77 and 126) were the largest contributors to the CB TEQs of the hepatopancreas samples that exceeded the action limit. C1 NOAA, Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, US Dept Commerce,Environm Conservat Div, Seattle, WA 98112 USA. RP Ylitalo, GM (reprint author), NOAA, Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, US Dept Commerce,Environm Conservat Div, 2725 Montlake Blvd E, Seattle, WA 98112 USA. NR 44 TC 16 Z9 20 U1 0 U2 2 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0090-4341 J9 ARCH ENVIRON CON TOX JI Arch. Environ. Contam. Toxicol. PD AUG PY 1999 VL 37 IS 2 BP 205 EP 219 PG 15 WC Environmental Sciences; Toxicology SC Environmental Sciences & Ecology; Toxicology GA 218YT UT WOS:000081581100009 PM 10398771 ER PT J AU Hufnagle, LC Camarata, SE Ernest, D Krone, CA Chan, SL Krahn, MM AF Hufnagle, LC Camarata, SE Ernest, D Krone, CA Chan, SL Krahn, MM TI Development and application of a high-performance liquid chromatography screening method for aromatic compounds in invertebrate tissues SO ARCHIVES OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY LA English DT Article ID COAL-COKING PLANT; VALDEZ OIL-SPILL; HOMARUS-AMERICANUS; HYDROCARBONS; SEDIMENTS; LOBSTER; FISH; METABOLITES; PROXIMITY; BILE AB Contamination of marine invertebrates by aromatic compounds (ACs) can occur from a variety of environmental. sources, bath natural and anthropogenic. Invertebrate species bioaccumulate ACs because they metabolize and eliminate them at a much slower rate than do vertebrates, such as fish. We have developed a high-performance liquid chromatography (HPLC) UV fluorescence screening method that measures ACs in invertebrate tissues. Screening methods have proven to be useful in response to environmental emergencies (e.g., oil spills) and in environmental monitoring because they are more rapid and less expensive than detailed analyses. This method was validated using three species of bivalves and lobster hepatopancreas and tail muscle as test samples. The AC screening method at naphthalene, phenanthrene, and benzo[a]pyrene wavelength pairs showed good correlation to GC/MS results. The method was also used successfully in response to the North Cape oil spill, off Narragansett, Rhode Island. C1 NOAA, Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, Environm Conservat Div,US Dept Commerce, Seattle, WA 98112 USA. RP Hufnagle, LC (reprint author), NOAA, Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, Environm Conservat Div,US Dept Commerce, 2725 Montlake Blvd E, Seattle, WA 98112 USA. NR 34 TC 4 Z9 5 U1 2 U2 4 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0090-4341 J9 ARCH ENVIRON CON TOX JI Arch. Environ. Contam. Toxicol. PD AUG PY 1999 VL 37 IS 2 BP 220 EP 226 PG 7 WC Environmental Sciences; Toxicology SC Environmental Sciences & Ecology; Toxicology GA 218YT UT WOS:000081581100010 ER PT J AU Currie, LA Klouda, GA Benner, BA Garrity, K Eglinton, TI AF Currie, LA Klouda, GA Benner, BA Garrity, K Eglinton, TI TI Isotopic and molecular fractionation in combustion; three routes to molecular marker validation, including direct molecular 'dating' (GC/AMS) SO ATMOSPHERIC ENVIRONMENT LA English DT Article; Proceedings Paper CT 6th International Conference on Carbonaceous Particles in the Atmosphere CY SEP 22-24, 1997 CL VIENNA, AUSTRIA DE combustion aerosol; carbon isotopic tracers; elemental carbon; PAH; isotopic and molecular fractionation; stages of combustion; GC AMS; model validation; biomass burning ID POLYCYCLIC AROMATIC-HYDROCARBONS; ACCELERATOR MASS-SPECTROMETRY; AIR-POLLUTION SOURCES; POLAR ATMOSPHERE; TRACERS; IDENTIFICATION; ALBUQUERQUE; AEROSOLS AB The identification of unique isotopic, elemental, and molecular markers for sources of combustion aerosol has growing practical importance because of the potential effects of fine particle aerosol on health, visibility and global climate. It is urgent, therefore, that substantial efforts be directed toward the validation of assumptions involving the use of such tracers for source apportionment. We describe here three independent routes toward carbonaceous aerosol molecular marker identification and validation: (1) tracer regression and multivariate statistical techniques applied to field measurements of mixed source, carbonaceous aerosols; (2) a new development in aerosol (14)C metrology: direct, pure compound accelerator mass spectrometry (AMS) by off-line GC/AMS ('molecular dating'); and (3) direct observation of isotopic and molecular source emissions during controlled laboratory combustion of specific fuels. Findings from the combined studies include. independent support for benzo(ghi)perylene as a motor vehicle tracer from the first (statistical) and second (direct 'dating') studies; a new indication, from the third (controlled combustion) study, of a relation between (13)C isotopic fractionation and PAH molecular fractionation, also linked with fuel and stage of combustion; and quantitative data showing the influence of both fuel type and combustion conditions on the yields of such species as elemental carbon and PAH, reinforcing the importance of exercising caution when applying presumed conservative elemental or organic tracers to fossil or biomass burning field data as in the first study. Published by Elsevier Science Ltd. C1 Natl Inst Stand & Technol, Chem Sci & Technol Lab, Gaithersburg, MD 20899 USA. Woods Hole Oceanog Inst, Dept Marine Chem & Geochem, Woods Hole, MA 02543 USA. RP Currie, LA (reprint author), Natl Inst Stand & Technol, Chem Sci & Technol Lab, Gaithersburg, MD 20899 USA. EM lloyd.currie@nist.gov NR 31 TC 38 Z9 40 U1 2 U2 7 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 AUG PY 1999 VL 33 IS 17 BP 2789 EP 2806 DI 10.1016/S1352-2310(98)00325-2 PG 18 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA 208DU UT WOS:000080975600019 ER PT J AU Norman, AL Hopper, JF Blanchard, P Ernst, D Brice, K Alexandrou, N Klouda, G AF Norman, AL Hopper, JF Blanchard, P Ernst, D Brice, K Alexandrou, N Klouda, G TI The stable carbon isotope composition of atmospheric PAHs SO ATMOSPHERIC ENVIRONMENT LA English DT Article; Proceedings Paper CT 6th International Conference on Carbonaceous Particles in the Atmosphere CY SEP 22-24, 1997 CL VIENNA, AUSTRIA DE carbon isotopes; polycyclic aromatic hydrocarbons; carbonaceous aerosols; CF-IRMS ID POLYCYCLIC AROMATIC-HYDROCARBONS; WOOD COMBUSTION; AMBIENT AIR; AEROSOLS; APPORTIONMENT AB A method for compound-specific stable carbon isotope analysis of atmospheric polycyclic aromatic hydrocarbons (PAHs) in carbonaceous aerosols is described. Atmospheric aerosol samples containing PAHs (C-10 to C-20) were collected on filters using a high-volume sampling technique, solvent extracted, taken through a cleanup procedure, separated by gas chromatography, oxidized to CO2 on-line, and introduced into an isotope ratio mass spectrometer for analysis. The method can be used to determine the isotope composition of a few nanograms of PAHs. This technique was used to analyse and compare the isotope composition of atmospheric PAHs from standards, as well as two samples from urban and rural locations. Isotopic variability in atmospheric PAHs is greater than measurement uncertainties which makes this a potentially useful technique for source identification when used together with concentration measurements. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Univ Calgary, Dept Phys & Astron, Calgary, AB T2N 1N4, Canada. Atmospher Environm Serv, Toronto, ON M3H 5T4, Canada. Natl Inst Stand & Technol, Chem Sci & Technol Lab, Gaithersburg, MD 20899 USA. RP Norman, AL (reprint author), Univ Calgary, Dept Phys & Astron, 2500 Univ Dr NW, Calgary, AB T2N 1N4, Canada. NR 20 TC 34 Z9 41 U1 0 U2 16 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 AUG PY 1999 VL 33 IS 17 BP 2807 EP 2814 DI 10.1016/S1352-2310(98)00358-6 PG 8 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA 208DU UT WOS:000080975600020 ER PT J AU Venkatram, A Pleim, J AF Venkatram, A Pleim, J TI The electrical analogy does not apply to modeling dry deposition of particles SO ATMOSPHERIC ENVIRONMENT LA English DT Article DE dry deposition; particulate matter; electrical analogy AB The most commonly used expression for dry deposition of particles is based on the electrical analogy. Because the electrical analogy is not consistent with the mass conservation equation, this expression for dry deposition velocity cannot be justified. This paper presents the correct expression. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Univ Calif Riverside, Coll Engn, Riverside, CA 92521 USA. NOAA, Air Resources Lab, Atmospher Sci Modeling Div, Res Triangle Pk, NC 27711 USA. RP Venkatram, A (reprint author), Univ Calif Riverside, Coll Engn, Riverside, CA 92521 USA. RI Pleim, Jonathan Pleim/C-1331-2017 OI Pleim, Jonathan Pleim/0000-0001-6190-6082 NR 2 TC 54 Z9 55 U1 1 U2 7 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 AUG PY 1999 VL 33 IS 18 BP 3075 EP 3076 DI 10.1016/S1352-2310(99)00094-1 PG 2 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA 194PZ UT WOS:000080203900018 ER PT J AU Wakamatsu, S Uno, I Ohara, T Schere, KL AF Wakamatsu, S Uno, I Ohara, T Schere, KL TI A study of the relationship between photochemical ozone and its precursor emissions of nitrogen oxides and hydrocarbons in Tokyo and surrounding areas SO ATMOSPHERIC ENVIRONMENT LA English DT Article DE photochemical ozone; NOx; NMHC; Urban Airshed Model (UAM) ID METROPOLITAN AREA; TRENDS AB The relationship between emission intensity of(nitrogen oxides) (NO,)I NC non-methane hydrocarbons (NMHC) and O-3 concentration covering the Kanto area (Tokyo and surrounding prefectures) were investigated based on data analysis and model simulation. The observed trend in NOx concentration increased and the NMHC/NOx ratio and NMHC concentration decreased from 1978 to 1990. These emission changes will act to change the place where the maximum ozone is observed in the Kanto area. The fact is that the location of the daily maximum oxidant concentration has moved further from the emission areas. To clarify the temporal and areal distribution of photochemical air pollution in the Kanto area, the Urban Airshed Model (UAM) was applied. Assuming 25% decrease in NMHC and 50% increase in NOx emission intensities, simulation result showed almost the same maximum O-3 value compared with the base-case simulation for 1981. On the other hand, the time when the maximum value appeared changed from 1400JST to 1600JST. Higher concentrations of oxidants were usually observed near the shore in the morning, and moved inland following sea breeze penetration. Under these meteorological conditions, the time shift obtained by the UAM simulation corresponds to the observed areal shift of the daily maximum O-3 concentration. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Natl Inst Environm Studies, Tsukuba, Ibaraki 305, Japan. Inst Behav Sci, Shinjuku Ku, Tokyo 162, Japan. NOAA, Atmospher Sci Modeling Div, Res Triangle Pk, NC 27711 USA. RP Wakamatsu, S (reprint author), Natl Inst Environm Studies, Onogawa 16-2, Tsukuba, Ibaraki 305, Japan. NR 15 TC 25 Z9 26 U1 0 U2 3 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 AUG PY 1999 VL 33 IS 19 BP 3097 EP 3108 DI 10.1016/S1352-2310(97)00493-7 PG 12 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA 196LY UT WOS:000080310900002 ER PT J AU Tarek, M Tu, K Klein, ML Tobias, DJ AF Tarek, M Tu, K Klein, ML Tobias, DJ TI Molecular dynamics simulations of supported phospholipid/alkanethiol bilayers on a gold(111) surface SO BIOPHYSICAL JOURNAL LA English DT Article ID PHASE DIPALMITOYLPHOSPHATIDYLCHOLINE BILAYER; LIPID BILAYERS; MEMBRANES; MONOLAYERS; POTENTIALS; CHAIN; MODEL; TEMPERATURE; BIOSENSORS; ANTIBODIES AB Molecular dynamics simulations have been used to investigate the structure of hybrid bilayers (HB) formed by dipalmitoylphosphatidylcholine (DPPC) lipid monolayers adsorbed on a hydrophobic alkanethiol self-assembled monolayer (SAM). The HE system was studied at 20 degrees C and 60 degrees C, and the results were compared with recent neutron reflectivity measurements (Meuse, C. W., S. Krueger, C. F. Majkrzak, J. A. Dura, J. Fu, J. T. Connor, and A. L. Plant. 1998. Biophys. J. 74:1388) and previous simulations of hydrated multilamellar bilayers (MLB) of DPPC (Tu, K., D. J. Tobias, and M. L. Klein. 1995. Biophys. J.69:2558; and 1996. 70:595). The overall structures of the HBs are in very good agreement with experiment. The structure of the SAM monolayer is hardly perturbed by the presence of the DPPC overlayer. The DPPC layer presents characteristics very similar to the MLB gel phase at low temperature and to the liquid crystal phase at high temperature. Subtle changes have been found for the lipid/water interface of the HBs compared to the MLBs. The average phosphatidylcholine headgroup orientation is less disordered, and this produces changes in the electric properties of the HB lipid/water interface; These changes are attributed to the fact that the aqueous environment of the lipids in these unilamellar films is different from that of MLB stacks. Finally, examination of the intramolecular and whole-molecule dynamics of the DPPC molecules in the fluid phase HE and MLB membranes revealed that the reorientations of the upper part of the acyl chains (near the acyl ester linkage) are slower, the single molecule protrusions are slightly damped, and the lateral rattling motions are significantly reduced in the HE compared with the MLB. C1 Univ Calif Irvine, Dept Chem, Irvine, CA 92697 USA. Univ Penn, Res Struct Matter Lab, Philadelphia, PA 19104 USA. NIST, Ctr Neutron Res, Gaithersburg, MD 20899 USA. RP Tobias, DJ (reprint author), Univ Calif Irvine, Dept Chem, Irvine, CA 92697 USA. RI Tobias, Douglas/B-6799-2015 NR 40 TC 40 Z9 41 U1 2 U2 14 PU BIOPHYSICAL SOCIETY PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 USA SN 0006-3495 J9 BIOPHYS J JI Biophys. J. PD AUG PY 1999 VL 77 IS 2 BP 964 EP 972 PG 9 WC Biophysics SC Biophysics GA 224VK UT WOS:000081920500028 PM 10423441 ER PT J AU Anadu, DI Scott, GI Fulton, MH AF Anadu, DI Scott, GI Fulton, MH TI Toxicity of DDT to the different life stages of the mummichog Fundulus heteroclitus (wabum) SO BULLETIN OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY LA English DT Article ID TESTS C1 S Carolina State Univ, Dept Biol Sci, Orangeburg, SC 29117 USA. NOAA, Natl Ocean Serv, Ctr Coastal Environm Hlth & Biomol Res, Charleston Lab, Charleston, SC 29422 USA. RP Anadu, DI (reprint author), S Carolina State Univ, Dept Biol Sci, 300 Coll St NE, Orangeburg, SC 29117 USA. NR 18 TC 4 Z9 5 U1 0 U2 2 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0007-4861 J9 B ENVIRON CONTAM TOX JI Bull. Environ. Contam. Toxicol. PD AUG PY 1999 VL 63 IS 2 BP 181 EP 187 PG 7 WC Environmental Sciences; Toxicology SC Environmental Sciences & Ecology; Toxicology GA 220MZ UT WOS:000081670900006 PM 10441634 ER PT J AU Chadwick, WW Gregg, TKP Embley, RW AF Chadwick, WW Gregg, TKP Embley, RW TI Submarine lineated sheet flows: a unique lava morphology formed on subsiding lava ponds SO BULLETIN OF VOLCANOLOGY LA English DT Article DE lineated sheet flow; submarine lava morphology; sea-floor eruptions; mid-ocean-ridge volcanism ID EAST PACIFIC RISE; KILAUEA VOLCANO; HYDROTHERMAL ACTIVITY; GALAPAGOS RIFT; FUCA RIDGE; HAWAII; GEOCHEMISTRY; EMPLACEMENT; EVOLUTION; INFLATION AB Lineated sheet flows are flat-lying, glassy lava flows characterized by a regular surface pattern of parallel grooves or furrows aligned with the flow direction. They are unique;to the submarine environment. We propose that the lineations are developed within the collapsed interiors of partially ponded lobate sheet flows that initially inflate and then drain out during emplacement, During lava drainout, the original lobate crust founders and a new crust begins to grow on the subsiding lava surface. Lineated now texture is created where molten lava emerges laterally from beneath a growing crust. The Lineations are formed by raking of the emerging lava surface by irregularities on the bottom edge of the crust and are preserved owing to rapid chilling by seawater. Therefore, lineated sheet flows are the product of a specific sequence of events over a short period of time during the course of a deep submarine eruption. C1 Oregon State Univ, Hatfield Marine Sci Ctr, NOAA, Newport, OR 97365 USA. SUNY Buffalo, Dept Geol Sci, Buffalo, NY 14260 USA. NOAA, PMEL, Hatfield Marine Sci Ctr, Newport, OR 97365 USA. RP Chadwick, WW (reprint author), Oregon State Univ, Hatfield Marine Sci Ctr, NOAA, Newport, OR 97365 USA. NR 36 TC 24 Z9 24 U1 0 U2 2 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0258-8900 J9 B VOLCANOL JI Bull. Volcanol. PD AUG PY 1999 VL 61 IS 3 BP 194 EP 206 DI 10.1007/s004450050271 PG 13 WC Geosciences, Multidisciplinary SC Geology GA 233KV UT WOS:000082426800004 ER PT J AU Gaggiotti, OE Vetter, RD AF Gaggiotti, OE Vetter, RD TI Effect of life history strategy, environmental variability, and overexploitation on the genetic diversity of pelagic fish populations SO CANADIAN JOURNAL OF FISHERIES AND AQUATIC SCIENCES LA English DT Article ID SARDINE SARDINOPS-SAGAX; PACIFIC SARDINE; OVERLAPPING GENERATIONS; NORTHERN ANCHOVY; ENGRAULIS-MORDAX; SIZE; AGE; FLUCTUATIONS; CALIFORNIA; FECUNDITY AB We study the effect of recruitment failures and variance in reproductive success on effective population size (N-e) in populations with type III survivorship curves. Special emphasis is put on determining the causes for the large differences in the genetic variability between populations of Pacific sardine (Sardinops sagax) and northern anchovy (Engraulis mordax). The results indicate that moderate differences in life history between ecologically related species can lead to substantial differences in N-e. The effect of fluctuations in vital rate parameters induced by environmental changes on N-e depends on the life history of each species. The ratio of N-e to census size is directly proportional to the total reproductive value of a population, but the sensitivity of this ratio to environmental fluctuations is inversely proportional to the generation overlap. The larger the generation overlap, the smaller the impact of environmental fluctuations on the level of genetic variability maintained by a population. The large difference in heterozygosity between Pacific sardine and northern anchovy populations is likely due to both life history differences between the two species and a recent arrival (founder event) of the Pacific sardine population to the California Current System. C1 Natl Marine Fisheries Serv, SW Fisheries Sci Ctr, La Jolla, CA 92038 USA. RP Gaggiotti, OE (reprint author), Univ Cambridge, Dept Zool, Downing St, Cambridge CB2 3EJ, England. RI Gaggiotti, Oscar/G-2459-2010 OI Gaggiotti, Oscar/0000-0003-1827-1493 NR 36 TC 35 Z9 35 U1 1 U2 9 PU NATL RESEARCH COUNCIL CANADA PI OTTAWA PA RESEARCH JOURNALS, MONTREAL RD, OTTAWA, ONTARIO K1A 0R6, CANADA SN 0706-652X J9 CAN J FISH AQUAT SCI JI Can. J. Fish. Aquat. Sci. PD AUG PY 1999 VL 56 IS 8 BP 1376 EP 1388 DI 10.1139/cjfas-56-8-1376 PG 13 WC Fisheries; Marine & Freshwater Biology SC Fisheries; Marine & Freshwater Biology GA 231TT UT WOS:000082326800006 ER PT J AU Elsayed, EE McLaughlin, SM Faisal, M AF Elsayed, EE McLaughlin, SM Faisal, M TI Protease inhibitors in plasma of the softshell clam Mya arenaria: identification and effects of disseminated sarcoma SO COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY B-BIOCHEMISTRY & MOLECULAR BIOLOGY LA English DT Article DE softshell clam; protease inhibitors; sarcoma; proteases; alpha(2)-macroglobulin ID SOFT-SHELL CLAMS; NEOPLASIA; PROTEINASES; MECHANISM; HEMOCYTES; MORTALITY; MOLLUSK AB Despite the ecologic and economic significance of the softshell clam (Mya arenaria), little is known about the humoral factors involved in its host defense mechanisms. Protease inhibitors, a group of proteins believed to play a role in host defense mechanisms against infections and proliferative diseases, have recently been identified in bivalve molluscs. In the present study we provide evidence for the presence of protease inhibitors in softshell clam plasma. Levels of protease inhibitory activities against the enzymes tested varied greatly, e.g. 1 mu g of plasma protein inhibited 35.3 +/- 9.69 ng pepsin (aspartic protease), 4.9 +/- 1.45 ng papain (cysteine protease) and 3.1 +/- 0.88 ng trypsin (serine protease). On the contrary, the level of anti-metalloprotease (thermolysin) activities was much lower. The sensitivity to methylamine and the ability to protect trypsin from active site trypsin inhibitors provided evidence for the presence of an alpha(2)-macroglobulin-like molecule in softshell clam plasma. In the Chesapeake Bay widespread epizootics of disseminated sarcoma have been described in M. arenaria populations. The impact of this lethal proliferative disorder on clam defense responses has received little attention. In this study the effects of sarcoma progression on plasma protease inhibitory activities were, therefore, assessed. Clams with early stages of sarcoma showed a non-significant decrease in protease inhibitor levels. Clams with advanced stages of sarcoma showed a significant decrease in the ability to inhibit trypsin and papain, while the protease inhibitory activity levels against aspartic and metalloprotease were completely exhausted. (C) 1999 Elsevier Science Inc. All rights reserved. C1 Coll William & Mary, Sch Marine Sci, Virginia Inst Marine Sci, Dept Environm Sci, Gloucester Point, VA 23062 USA. NOAA, Natl Ocean Serv, Ctr Coastal Environm Hlth & Biomol Res, Oxford, MD 21654 USA. RP Faisal, M (reprint author), Coll William & Mary, Sch Marine Sci, Virginia Inst Marine Sci, Dept Environm Sci, Gloucester Point, VA 23062 USA. NR 27 TC 9 Z9 9 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0305-0491 J9 COMP BIOCHEM PHYS B JI Comp. Biochem. Physiol. B-Biochem. Mol. Biol. PD AUG PY 1999 VL 123 IS 4 BP 427 EP 435 DI 10.1016/S0305-0491(99)00089-9 PG 9 WC Biochemistry & Molecular Biology; Zoology SC Biochemistry & Molecular Biology; Zoology GA 239JC UT WOS:000082764100012 ER PT J AU Hertel, F Ballance, LT AF Hertel, F Ballance, LT TI Wing ecomorphology of seabirds from Johnston Atoll SO CONDOR LA English DT Article DE ecomorphology; fight; Laridae; Phaethontidae; Procellariidae; seabirds; Sulidae; wings ID EASTERN TROPICAL PACIFIC; FLIGHT ENERGETICS; SOOTY TERNS; ALBATROSSES; MODEL AB Wing morphology of nine species of seabirds from Johnston Atoll in the central tropical Pacific was analyzed to determine how wing size and shape correlated with observed foraging behavior and, in some species, the energetic cost of flight. Red-tailed Tropicbirds (Phaethon rubricauda) and Christmas Shearwaters (Puffinus nativitatis) had lower wing areas, shorter wing spans, and higher relative wing loading than would be predicted from mass alone. Brown Noddies (Anous stolidus) and Red-footed Boobies (Sula sula) had lower wing loading, Brown Boobies (Sula leucogaster) and Sooty Terns (Sterna fuscata) had higher aspect ratios, and Brown Noddies had lower aspect ratio than would be predicted from mass alone. Aspect ratio showed greater intraspecific variation than the other variables. In most cases, predicted differences in wing morphology correlated well with observed foraging differences among species, and species that did not differ significantly in body mass differed with respect to wing size and shape; these morphological differences reflected varying flight and foraging behaviors. Sooty Terns had a higher aspect ratio and higher wing loading than Brown Noddies reflecting their more pelagic lifestyle, and Christmas Shearwaters had a lower aspect ratio and higher wing loading than Wedge-tailed Shearwaters (Puffinus pacificus) reflecting their pursuit plunging behavior. C1 Univ Calif Los Angeles, Dept Biol, Los Angeles, CA 90095 USA. NOAA, SW Fisheries Sci Ctr, NMFS, Ecol Program, La Jolla, CA 92037 USA. RP Hertel, F (reprint author), Univ Calif Los Angeles, Dept Biol, Los Angeles, CA 90095 USA. NR 36 TC 29 Z9 34 U1 0 U2 19 PU COOPER ORNITHOLOGICAL SOC PI LAWRENCE PA ORNITHOLOGICAL SOC NORTH AMER PO BOX 1897, LAWRENCE, KS 66044-8897 USA SN 0010-5422 J9 CONDOR JI Condor PD AUG PY 1999 VL 101 IS 3 BP 549 EP 556 DI 10.2307/1370184 PG 8 WC Ornithology SC Zoology GA 226CG UT WOS:000082002300009 ER PT J AU Rintoul, SR Bullister, JL AF Rintoul, SR Bullister, JL TI A late winter hydrographic section from Tasmania to Antarctica SO DEEP-SEA RESEARCH PART I-OCEANOGRAPHIC RESEARCH PAPERS LA English DT Article ID SOUTH-PACIFIC OCEAN; CIRCUMPOLAR CURRENT; DRAKE PASSAGE; WATER MASSES; BOTTOM WATER; WEDDELL SEA; CIRCULATION; TRANSPORT; VENTILATION; ATLANTIC AB A hydrographic section between Tasmania and Antarctica was occupied in late winter 1991 as part of the World Ocean Circulation Experiment (WOCE). The primary purpose of the WOCE repeat section SR3 is to measure the exchange between the Indian and Pacific Oceans south of Australia. This paper describes the fronts, water masses and transport observed on the first occupation of the repeat section. The Subantarctic Front (SAF) is located between 50 degrees S and 51 degrees S and is the most striking feature of the vertical sections. Two additional fronts at 53 degrees S and 59 degrees S are associated with the Polar Front (PF), part of which turns northward to flow along the section before turning back to the east near 53 degrees S. Very deep (> 500 m) mixed layers are found north of the SAF, confirming that Subantarctic Mode Water (SAMW) is formed in this region by deep convection in winter. Chlorofluorocarbons (CFCs) are significantly undersaturated (approximate to 90-92% of equilibrium values) in these deep mixed layers indicating that gas exchange rates are not rapid enough to bring these deep mixed layers to equilibrium by the end of the winter period of deep convective mixing. Northward Ekman drift of cold, fresh water across the SAF is likely to be responsible for the cooler, fresher mixed layers observed immediately north of the SAF. The Antarctic Intermediate Water (AAIW) on the SR3 section is relatively low in oxygen and CFCs(approximate to 60-70% and 10-20% of saturation values, respectively), high in potential vorticity, and high in nutrients. These characteristics suggest that the AAIW on this section is not renewed by direct and rapid ventilation near this location. Water mass properties suggest that water from the Tasman Sea spreads south and west across the northern portion of the SR3 section between 800 and 3000 m depth. A cold, fresh, CFC-rich variety of Antarctic Bottom Water is formed along the Wilkes-Adelie coast of Antarctica. The net transport across the section relative to the deepest common depth is 160 Sv. The band of eastward flow between 50 degrees S and 53 degrees S including the SAF carries 137Sv to the east and dominates the net transport. Weaker flow south of 58 degrees S contributes an additional 70Sv. The eastward flow is compensated in part by 37Sv of westward flow between Tasmania and 48.5 degrees S and 8Sv of flow to the west over the southern flank of the mid-ocean ridge. The trajectories of six ALACE floats deployed at about 950m confirm the sense of flow inferred from the choice of a deep reference level. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 CSIRO, Marine Res, Hobart, Tas 7001, Australia. NOAA, Pacific Marine Environm Lab, Seattle, WA 98115 USA. Antarct Cooperat Res Ctr, Hobart, Tas, Australia. RP Rintoul, SR (reprint author), CSIRO, Marine Res, GPO Box 1538, Hobart, Tas 7001, Australia. RI Rintoul, Stephen /A-1471-2012 OI Rintoul, Stephen /0000-0002-7055-9876 NR 70 TC 156 Z9 161 U1 0 U2 6 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 AUG PY 1999 VL 46 IS 8 BP 1417 EP 1454 DI 10.1016/S0967-0637(99)00013-8 PG 38 WC Oceanography SC Oceanography GA 205ZR UT WOS:000080851900005 ER PT J AU Sakuma, KM Ralston, S Lenarz, WH Embury, M AF Sakuma, KM Ralston, S Lenarz, WH Embury, M TI Effects of the parasitic copepod Cardiodectes medusaeus on the lanternfishes Diaphus theta and Tarletonbeania crenularis off central California SO ENVIRONMENTAL BIOLOGY OF FISHES LA English DT Article DE otoliths; somatic growth; interspecific variability ID OTOLITH AB In two distinct survey areas, offshore from the Farallon Islands and in the vicinity of Pioneer Canyon off central California, Diaphus theta was significantly more prone to infection by the parasitic copepod Cardiodectes medusaeus than Tarletonbeania crenularis. In addition, D. theta was more heavily parasitized in the Pioneer Canyon area than in the Farallon Islands area. A linear relationship was shown between log(e)-transformed otolith size and log(e)-transformed SL and between log(e)-transformed dry weight and log(e)-transformed SL for D. theta and T. crenularis in both survey areas. A test of slopes showed differences between the two survey areas for both species. Lower dry weights were observed for both D. theta and T. crenularis, in parasitized versus non-parasitized specimens in the Pioneer Canyon area. In the Farallon Islands area, however, no differences were observed. Larger otolith sizes were observed in parasitized D. theta versus non-parasitized specimens in the Pioneer Canyon area, while no differences were observed in the Farallon Islands area. In contrast, T. crenularis had larger otolith sizes in parasitized versus non-parasitized specimens in the Farallon Islands area, while no significant differences were observed in the Pioneer Canyon area. These findings provided evidence of geographic and interspecific variability in both the prevalence and the physiological effects of parasitism. C1 Natl Marine Fisheries Serv, SW Fisheries Sci Ctr, Tiburon Lab, Tiburon, CA 94920 USA. RP Sakuma, KM (reprint author), Natl Marine Fisheries Serv, SW Fisheries Sci Ctr, Tiburon Lab, 3150 Paradise Dr, Tiburon, CA 94920 USA. NR 14 TC 4 Z9 4 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0378-1909 J9 ENVIRON BIOL FISH JI Environ. Biol. Fishes PD AUG PY 1999 VL 55 IS 4 BP 423 EP 430 DI 10.1023/A:1007546427962 PG 8 WC Ecology; Marine & Freshwater Biology SC Environmental Sciences & Ecology; Marine & Freshwater Biology GA 227NH UT WOS:000082086100010 ER PT J AU Kiselev, SB Friend, DG AF Kiselev, SB Friend, DG TI Cubic crossover equation of state for mixtures SO FLUID PHASE EQUILIBRIA LA English DT Article DE binary mixtures; carbon dioxide; critical state; cubic equation of state; ethane; methane; thermodynamic properties; vapor-liquid equilibria ID EXTENDED CRITICAL REGION; PENG-ROBINSON EQUATION; THERMODYNAMIC PROPERTIES; CARBON-DIOXIDE; BINARY-MIXTURES; TEMPERATURE RELATION; LIQUID-EQUILIBRIA; SINGLE-COMPONENT; HOMOGENEOUS GAS; PHASE-BEHAVIOR AB In a preceding publication [S.B. Kiselev, Fluid Phase Equilibria 147 (1998) 7], a general procedure was proposed for transforming any classical equation of state (EOS) for pure fluids into a crossover EOS which incorporates the scaling laws asymptotically close to the critical point and is transformed into the original classical EOS far from the critical point. In the present paper, we extend this procedure and develop a cubic crossover equation of state for mixtures. A comparison is made with experimental data for pure methane, ethane, CO2, and for the methane + ethane and CO2 + ethane mixtures in the one- and two-phase regions. The cubic crossover equation of state yields a satisfactory representation of the thermodynamic properties and the vapor-liquid equilibria of pure fluids and fluid mixtures in a large range of temperatures and densities, including the dilute gas limit, liquid densities, and the critical region. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Natl Inst Stand & Technol, Phys & Chem Properties Div, Boulder, CO 80303 USA. RP Kiselev, SB (reprint author), Colorado Sch Mines, Dept Chem Engn & Petr Refining, Golden, CO 80401 USA. EM skiselev@mines.edu NR 93 TC 74 Z9 76 U1 1 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0378-3812 EI 1879-0224 J9 FLUID PHASE EQUILIBR JI Fluid Phase Equilib. PD AUG PY 1999 VL 162 IS 1-2 BP 51 EP 82 DI 10.1016/S0378-3812(99)00182-X PG 32 WC Thermodynamics; Chemistry, Physical; Engineering, Chemical SC Thermodynamics; Chemistry; Engineering GA 225QD UT WOS:000081971500004 ER PT J AU Senturker, S Dizdaroglu, M AF Senturker, S Dizdaroglu, M TI The effect of experimental conditions on the levels of oxidatively modified bases in DNA as measured by gas chromatography-mass spectrometry: How many modified bases are involved? Prepurification or not? SO FREE RADICAL BIOLOGY AND MEDICINE LA English DT Article DE derivatization; formamidopyrimidines; gas chromatography-mass spectrometry; 5-hydroxycytosine; 8-hydroxyguanine; 8-hydroxyadenine; oxidative DNA damage; free radicals ID CULTURED-MAMMALIAN-CELLS; QUANTITATIVE-DETERMINATION; ELECTROCHEMICAL DETECTION; CHEMICAL DETERMINATION; ARTIFACTUAL FORMATION; HEPATIC CHROMATIN; DAMAGE; RADIATION; REPAIR; RATS AB Recently, an artifactual formation of a number of modified DNA bases has been alleged during derivatization of DNA hydrolysates to be analyzed by gas chromatography-mass spectrometry (GC-MS). These modified bases were 8-hydroxyguanine (8-OH-Gua), 5-hydroxycytosine (5-OH-Cyt), 8-hydroxyadenine (8-OH-Ade), 5-hydroxymethyl-uracil (5-OHMeUra), and 5-formyluracil, which represent only a small percentage of more than 20 modified DNA bases that can be analyzed by GC-MS. However, relevant papers reporting the levels of these modified bases in DNA of various sources have not been cited, and differences in experimental procedures have not been discussed. We investigated the levels of modified bases in calf thymus DNA by GC-MS using derivatization at three different temperatures. The results obtained with GC/isotope-dilution MS showed that the levels of 5-OH-Cyt, 8-OH-Ade, 5-OH-Ura, and 5-OHMeUra were not affected by increasing the derivatization temperature From 23 degrees C to 120 degrees C. The level of 8-OH-Gua was found to be higher at 120 degrees C. However, this level was much lower than those reported previously. Formamidopyrimidines were readily analyzed in contrast to some recent claims. The addition of trifluoroacetic acid (TFA) adversely affected the levels of pyrimidine-derived lesions, suggesting that TFA is not suitable for simultaneous measurement of both pyrimidine- and purine-derived lesions. The data obtained were also compared with those previously published. Our data and this comparison indicate that no artifactual formation of 5-OH-Cyt, 8-OH-Ade, and 5-OHMeUra occurred under our experimental conditions in contrast to recent claims, and no prepurification of DNA hydrolysates by a tedious procedure is necessary for accurate quantification of these compounds. The artifactual formation of 8-OH-Gua can be eliminated by derivatization at room temperature for at least 2 h, without the use of TFA. The results in this article and their comparison with published data indicate that different results may be obtained in different laboratories using different experimental conditions. The data obtained in various laboratories should be compared by discussing all relevant published data and scientific facts, including differences between experimental conditions used in different laboratories. (C) 1999 Elsevier Science Inc. C1 Natl Inst Stand & Technol, Chem Sci & Technol Lab, Gaithersburg, MD 20899 USA. RP Dizdaroglu, M (reprint author), Natl Inst Stand & Technol, Chem Sci & Technol Lab, 100 Bur Dr,Stop 8311, Gaithersburg, MD 20899 USA. EM miral@nist.gov NR 49 TC 51 Z9 52 U1 1 U2 4 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0891-5849 J9 FREE RADICAL BIO MED JI Free Radic. Biol. Med. PD AUG PY 1999 VL 27 IS 3-4 BP 370 EP 380 DI 10.1016/S0891-5849(99)00069-6 PG 11 WC Biochemistry & Molecular Biology; Endocrinology & Metabolism SC Biochemistry & Molecular Biology; Endocrinology & Metabolism GA 227YL UT WOS:000082107500017 PM 10468211 ER PT J AU Anson, RM Senturker, S Dizdaroglu, M Bohr, VA AF Anson, RM Senturker, S Dizdaroglu, M Bohr, VA TI Measurement of oxidatively induced base lesions in liver from Wistar rats of different ages SO FREE RADICAL BIOLOGY AND MEDICINE LA English DT Article DE oxidative DNA damage; GC/MS; mitochondrial DNA; aging; free radicals ID CHROMATOGRAPHY MASS-SPECTROMETRY; FORMAMIDOPYRIMIDINE DNA GLYCOSYLASE; HUMAN MITOCHONDRIAL-DNA; MAMMALIAN CHROMATIN; IONIZING-RADIATION; HYDROGEN-PEROXIDE; NUCLEAR-DNA; DAMAGE; REPAIR; OXYGEN AB Mitochondrial and nuclear DNA were isolated from the livers of young (6-7 month) and old (23-24 month) Wistar rats and the levels of 10 different oxidatively induced lesions were analyzed by gas chromatography/mass spectrometry. This is the first study to measure several different oxidatively induced base lesions in both mitochondrial and nuclear DNA as a function of age. No significant age effects were observed for any lesion. Furthermore, contrary to expectations, we did not observe elevated levels of oxidatively induced base lesions in mitochondrial DNA. This contrasts with 50-fold differences reported for several lesions between mitochondrial and nuclear DNA from porcine liver (Zastawny et al., Free Radic. Biol. Med. 24:722-725, 1998). The fact that different lesion levels are observed even when similar techniques are employed emphasizes that the role of oxidative mitochondrial DNA damage and its repair in aging must continue to be the subject of intense investigation. Questions concerning endogenous levels of damage should be revisited as existing methods are improved and new methods become available. (C) 1999 Elsevier Science Inc. C1 NIA, Gerontol Res Ctr, Mol Genet Lab, NIH, Baltimore, MD 21224 USA. Natl Inst Stand & Technol, Chem Sci & Technol Lab, Gaithersburg, MD 20899 USA. RP Bohr, VA (reprint author), NIA, Gerontol Res Ctr, Mol Genet Lab, NIH, 5600 Nathan Shock Dr,Box 01, Baltimore, MD 21224 USA. NR 30 TC 48 Z9 48 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0891-5849 J9 FREE RADICAL BIO MED JI Free Radic. Biol. Med. PD AUG PY 1999 VL 27 IS 3-4 BP 456 EP 462 DI 10.1016/S0891-5849(99)00091-X PG 7 WC Biochemistry & Molecular Biology; Endocrinology & Metabolism SC Biochemistry & Molecular Biology; Endocrinology & Metabolism GA 227YL UT WOS:000082107500028 PM 10468222 ER PT J AU Resing, JA Sansone, FJ AF Resing, JA Sansone, FJ TI The chemistry of lava-seawater interactions: The generation of acidity SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Article ID DE-FUCA RIDGE; KILAUEA VOLCANO; HYDROTHERMAL FLUIDS; QUARTZ DISSOLUTION; CARBON-DIOXIDE; CLEFT SEGMENT; BLACK SMOKER; HEAVY-METAL; VENT FLUIDS; HAWAII AB High concentrations of acid were found to arise from the interaction between molten rock and seawater at the shoreline of Kilauea Volcano, Hawaii. A series of field samplings and experiments show that the acid was derived from two sources: the release of magmatic volatiles and water-rock reactions. Although the bulk of the magmatic volatiles (CO2, H2O, and SO2) are vented at Puu Oo cinder cone before the lava's transit downslope to the ocean, a portion of the sulfur (S) and fluoride (F) gasses are retained by the lava and then are released partially when the lava is quenched by seawater. The primary water-rock reaction responsible for acid formation appears to be Na-metasomatism, which is much different from the predominant acid-forming reaction found in submarine hydrothermal systems, Mg-metasomatism. Analyses of surface seawater and of precipitation (rain) deposited at the shore show that similar to 30% of the acid comes from magmatic gasses with the balance from reactions between the rock and the salts found in seawater. Experimental results show that similar to 4 +/- 1.5 mEq of acid are formed per kilogram of lava entering the ocean, and of this 1 +/- 0.5 mEq/kg of lava came from S and F, with the balance coming from water-rock reactions. On the basis of lava extrusion rates, similar to 200-720 x 10(6) Eq/yr of acid are being formed at this site. The deposition of the acid results in the alteration of subaerial lava hows along the coast, and the lowering of the pH of the adjacent surface ocean waters by more than 1 unit. The ejection of this acid into the atmosphere contributes to the formation of an extensive haze downwind of the lava entries. Copyright (C) 1999 Elsevier Science Ltd. C1 NOAA, Pacific Marine Environm Lab, Seattle, WA 98115 USA. Univ Hawaii Manoa, Sch Ocean Earth Sci & Technol, Dept Oceanog, Honolulu, HI 96822 USA. RP Resing, JA (reprint author), NOAA, Pacific Marine Environm Lab, 7600 Sand Point Way Ne, Seattle, WA 98115 USA. RI Sansone, Francis/B-9915-2013 NR 82 TC 11 Z9 11 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 AUG PY 1999 VL 63 IS 15 BP 2183 EP 2198 DI 10.1016/S0016-7037(99)00193-3 PG 16 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 235VU UT WOS:000082563900003 ER PT J AU Russell, CT Zhou, XW Chi, PJ Kawano, H Moore, TE Peterson, WK Cladis, JB Singer, HJ AF Russell, CT Zhou, XW Chi, PJ Kawano, H Moore, TE Peterson, WK Cladis, JB Singer, HJ TI Sudden compression of the outer magnetosphere associated with an ionospheric mass ejection SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID MAGNETIC-FIELD AB On September 24, 1998 at 2345 UT the magnetosphere was suddenly compressed as the dynamic pressure of the solar wind rapidly rose from 2 to 15 nPa At the Polar spacecraft, at high altitudes above the center of the northern polar cap, a remarkably smooth increase in the field strength occurred while the plasma properties changed abruptly, as described in an accompanying paper. Comparisons with models and an examination of the wave amplitudes during the compression indicate that the initial change in plasma properties was most probably due to convection of pre-existing boundary layer plasma to the location of Polar rather than due to local heating by betatron acceleration and ion cyclotron waves. The smoothness of the increase in field strength is attributed to the very high velocity of compressional waves in the tail that outrun the advancing solar wind disturbance. The signatures as measured by GOES 10 at 1444 LT and at GOES 8 at 1846 LT in low latitude geosynchronous orbit are the more familiar sudden jump on the dayside, where the density is high and the compressional wave velocity low, and a weak change on the nightside, where tail current changes oppose the effects of the dayside magnetopause currents. This event is an ideal candidate for collaborative investigation of the effects of a classical sudden storm commencement on the magnetosphere. C1 Univ Calif Los Angeles, Inst Geophys & Planetary Phys, Los Angeles, CA 90095 USA. Kyushu Univ 33, Fukuoka 812, Japan. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Lockheed Martin, Palo Alto Res Lab, Palo Alto, CA 94304 USA. NOAA, R E SE, Boulder, CO 80303 USA. RP Russell, CT (reprint author), Univ Calif Los Angeles, Inst Geophys & Planetary Phys, Los Angeles, CA 90095 USA. RI Moore, Thomas/D-4675-2012; Peterson, WK/A-8706-2009; OI Moore, Thomas/0000-0002-3150-1137; Peterson, WK/0000-0002-1513-6096; Russell, Christopher/0000-0003-1639-8298 NR 9 TC 32 Z9 33 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 1 PY 1999 VL 26 IS 15 BP 2343 EP 2346 DI 10.1029/1999GL900455 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 221WT UT WOS:000081750700031 ER PT J AU Portmann, RW Brown, SS Gierczak, T Talukdar, RK Burkholder, JB Ravishankara, AR AF Portmann, RW Brown, SS Gierczak, T Talukdar, RK Burkholder, JB Ravishankara, AR TI Role of nitrogen oxides in the stratosphere: A reevaluation based on laboratory studies SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID AEROSOLS AB The changes in chemical partitioning and stratospheric O-3 abundance due to the recently measured rate coefficients for the O + NO2, OH + HNO3, and OH + NO2 reactions are examined using a two-dimensional model. The rate constant changes increase NOx abundance (up to 40%) and NOx-catalyzed O-3 destruction, and extend down by several kilometers the altitude region where NOx dominates catalytic O-3 destruction. Reductions in the abundance of HOx (10-30%) and ClOx (20-40%) in the lower stratosphere partially buffer the effect on column O-3 amount. Column O-3 at middle and high latitudes is reduced by 2-10% depending on season for current halogen levels. The model derived long-term O-3 trend at midlatitudes due to increases in anthropogenic halogens is reduced by approximately 30%. C1 NOAA, ERL, Aeron Lab, Boulder, CO 80303 USA. Univ Warsaw, Dept Chem, PL-02089 Warsaw, Poland. Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. Univ Colorado, Dept Chem & Biochem, Boulder, CO 80309 USA. RP Portmann, RW (reprint author), NOAA, ERL, Aeron Lab, R-E-AL2,325 Broadway, Boulder, CO 80303 USA. RI Portmann, Robert/C-4903-2009; TALUKDAR, RANAJIT/G-4530-2013; Burkholder, James/H-4914-2013; Brown, Steven/I-1762-2013; Ravishankara, Akkihebbal/A-2914-2011 OI Portmann, Robert/0000-0002-0279-6087; TALUKDAR, RANAJIT/0000-0001-6017-8431; NR 14 TC 41 Z9 41 U1 3 U2 5 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD AUG 1 PY 1999 VL 26 IS 15 BP 2387 EP 2390 DI 10.1029/1999GL900499 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 221WT UT WOS:000081750700043 ER PT J AU Jonsson, B Waples, RS Friedland, KD AF Jonsson, B Waples, RS Friedland, KD TI Extinction considerations for diadromous fishes SO ICES JOURNAL OF MARINE SCIENCE LA English DT Article; Proceedings Paper CT ICES Annual Science Conference CY SEP 25-26, 1997 CL BALTIMORE, MARYLAND SP Int Council Explorat Sea DE measuring extinction; population threats; causes of extinction; risk assessment; habitat restoration; population recovery ID ATLANTIC SALMON; EXPERIENCE; WILD AB Among diadromous fishes, the sturgeons are particularly threatened with 13 of 15 species considered endangered or vulnerable to extinction worldwide. These species have low intrinsic rate of growth and specialized habitat requirements making them sensitive to environmental changes and human exploitation. Habitat destruction, degradation, and alternations are probably prime causes of extinction in diadromous fishes. The spread of alien species, naturally or transported by humans to new environments, may be the second most important cause. Harvest is a contributing factor to extinction risk for many diadromous populations, although there is no known example where overfishing has led directly to the extinction of species. Population viability analysis is a method which may be used for evaluating extinction risk. However, uncertainties associated with parameter estimation and model choice limit its usefulness. Avoiding short-term extinctions is difficult enough, but restoration and recovery of natural populations present a whole new array of challenges. The understanding of the genetic population structure of the species is essential in this context. Captive rearing has some use as tool to assist stock restoration. However, artificial propagation will not lead to recovery unless the fundamental problems that caused the population declines are addressed. (C) 1999 International Council for the Exploration of the Sea. C1 Norwegian Inst Nat Management, N-0105 Oslo, Norway. NOAA, NW Fisheries Sci Ctr, Conservat Biol Div, Seattle, WA 98112 USA. NE Fisheries Sci Ctr, Populat Dynam Branch, Woods Hole, MA 02543 USA. RP Jonsson, B (reprint author), Norwegian Inst Nat Management, Dronningens Gt 13,POB 736 Sentrum, N-0105 Oslo, Norway. RI Waples, Robin/K-1126-2016 NR 31 TC 33 Z9 34 U1 2 U2 16 PU ACADEMIC PRESS LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 1054-3139 J9 ICES J MAR SCI JI ICES J. Mar. Sci. PD AUG PY 1999 VL 56 IS 4 BP 405 EP 409 DI 10.1006/jmsc.1999.0483 PG 5 WC Fisheries; Marine & Freshwater Biology; Oceanography SC Fisheries; Marine & Freshwater Biology; Oceanography GA 230HA UT WOS:000082244700001 ER PT J AU Wainwright, TC Kope, RG AF Wainwright, TC Kope, RG TI Methods of extinction risk assessment developed for US West Coast salmon SO ICES JOURNAL OF MARINE SCIENCE LA English DT Article; Proceedings Paper CT ICES Annual Science Conference CY SEP 25-26, 1997 CL BALTIMORE, MARYLAND SP Int Council Explorat Sea DE extinction; Pacific salmon; population dynamics; genetics; Oncorhynchus; risk assessment ID PACIFIC SALMON; CONSERVATION; STOCKS; TRENDS AB In assessing extinction risk for Pacific salmon (Oncorhynchus spp.), a variety of interacting risk factors are considered,. some of which can be quantified but many of which are qualitative. In addition to the common measures of population abundance and trends for individual populations, these factors include ecological and genetic effects of hatchery fish, changes in Life history traits, selective effects of harvest, trends in freshwater habitat condition, and climate variation. Combining such information into an assessment of the overall degree of risk facing populations and species relies heavily on scientific judgement rather than explicit quantitative criteria. Tb organize multifactor information and ensure consistency, a risk-matrix method has been implemented in which individual risk factors are scored on a 5-point scale, and then combined into an overall assessment of extinction risk. (C) 1999 international Council for the Exploration of the Sea. C1 NW Fisheries Sci Ctr, US Natl Marine Fisheries Serv, Newport, OR 97365 USA. NW Fisheries Sci Ctr, US Natl Marine Fisheries Serv, Seattle, WA 98112 USA. RP Wainwright, TC (reprint author), NW Fisheries Sci Ctr, US Natl Marine Fisheries Serv, 2030 S Marine Sci Dr, Newport, OR 97365 USA. RI Wainwright, Thomas/F-4550-2010 OI Wainwright, Thomas/0000-0001-5147-479X NR 20 TC 5 Z9 5 U1 0 U2 3 PU ACADEMIC PRESS LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 1054-3139 J9 ICES J MAR SCI JI ICES J. Mar. Sci. PD AUG PY 1999 VL 56 IS 4 BP 444 EP 448 DI 10.1006/jmsc.1999.0451 PG 5 WC Fisheries; Marine & Freshwater Biology; Oceanography SC Fisheries; Marine & Freshwater Biology; Oceanography GA 230HA UT WOS:000082244700006 ER PT J AU Swartzman, G Brodeur, R Napp, J Hunt, G Demer, D Hewitt, R AF Swartzman, G Brodeur, R Napp, J Hunt, G Demer, D Hewitt, R TI Spatial proximity of age-0 walleye pollock (Theragra chalcogramma) to zooplankton near the Pribilof Islands, Bering Sea, Alaska SO ICES JOURNAL OF MARINE SCIENCE LA English DT Article DE acoustics; walleye pollock; zooplankton patchiness; predator-prey relationships; Generalized Additive models; distance-based proximity ID SOUND-SCATTERING; BACKSCATTERING; VARIANCE; FISHES; MODELS; KRILL; SCALE AB Acoustic surveys, conducted in September 1994 and 1995 in the neighbourhood of the Pribilof Islands, Alaska, collected data at three frequencies, making possible the location of pollock shoals and patches of zooplankton along the survey transect. These patches were identified using threshold and morphological filters on echosounder images taken at 38 kHz (fish identification) and 120 and 200 kHz (plankton identification). We checked the morphological methods by comparing the depth distribution of acoustically determined plankton with zooplankton from net surveys and found them in general agreement. Our ability to spatially map patches of plankton and shoals of fish (mostly pollock) along the survey transects led to our examining the spatial proximity between pollock and plankton patches. Results, using both intervaI- and distance-based measures, suggested that fish-plankton proximity was affected by plankton biomass. When the plankton biomass was low, fish tended to remain close to existing plankton patches, while at high plankton biomass there was no consistent small-scale proximity relationship. At intermediate plankton densities there was no particular distance-based proximity of plankton patches to fish shoals. However, the interval-based fish densities tended to increase with increasing plankton density up to some plankton density threshold, above which there was no clear association between fish and plankton density. These findings suggest the existence of plankton biomass density thresholds, both overall and within plankton patches that may influence pollock feeding strategies. They also suggest a possible method for empirically estimating these thresholds using multi-frequency acoustic survey data. (C) 1999 International Council for the Exploration of the Sea. C1 Univ Washington, Appl Phys Lab, Seattle, WA 98105 USA. Univ Washington, Sch Fisheries, Seattle, WA 98105 USA. NOAA, Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr, Seattle, WA 98115 USA. Univ Calif Irvine, Dept Evolutionary Biol, Irvine, CA 92697 USA. SW Fisheries Sci Ctr, Natl Marine Fisheries Serv, La Jolla, CA USA. RP Swartzman, G (reprint author), Univ Washington, Appl Phys Lab, Seattle, WA 98105 USA. OI Hunt, George/0000-0001-8709-2697 NR 37 TC 46 Z9 46 U1 0 U2 3 PU ACADEMIC PRESS LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 1054-3139 J9 ICES J MAR SCI JI ICES J. Mar. Sci. PD AUG PY 1999 VL 56 IS 4 BP 545 EP 560 DI 10.1006/jmsc.1999.0480 PG 16 WC Fisheries; Marine & Freshwater Biology; Oceanography SC Fisheries; Marine & Freshwater Biology; Oceanography GA 230HA UT WOS:000082244700015 ER PT J AU Fourestie, B Altman, Z Kanda, M AF Fourestie, B Altman, Z Kanda, M TI Anechoic chamber evaluation using the matrix pencil method SO IEEE TRANSACTIONS ON ELECTROMAGNETIC COMPATIBILITY LA English DT Article DE absorber; anechoic chamber; matrix pencil method AB A new method for evaluation of an anechoic chamber using the matrix pencil method is presented. A signal measured between two antennas placed in an anechoic chamber is sliced into small frequency intervals and is processed using the matrix pencil method. In each interval, the measured signal is decomposed into its propagating-wave components, which correspond to a direct propagation between two antennas and reflected propagating waves from absorbing walls, The ratio of amplitudes of the reflected wave components with respect to the direct path propagation gives a new measure of quality factor for an anechoic chamber. C1 France Telecom, CNET, F-92794 Issy Les Moulineaux 9, France. Natl Inst Stand & Technol, Boulder, CO 80303 USA. RP Fourestie, B (reprint author), France Telecom, CNET, F-92794 Issy Les Moulineaux 9, France. NR 11 TC 15 Z9 16 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9375 J9 IEEE T ELECTROMAGN C JI IEEE Trans. Electromagn. Compat. PD AUG PY 1999 VL 41 IS 3 BP 169 EP 174 DI 10.1109/15.784150 PG 6 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA 229EL UT WOS:000082180500001 ER PT J AU Jones, CA AF Jones, CA TI Permittivity and permeability measurements using stripline resonator cavities - A comparison SO IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT LA English DT Article DE dielectric materials; ferrites; intercomparison; measurements; permeability; permittivity; stripline resonator AB The permittivity and permeability of five materials were measured during a comparison of the stripline resonator cavity technique, The National Institute of Standards and Technology (NIST) organized this intercomparison in which a total of seven organizations participated. Each participant measured two dielectric materials and three magnetic materials. Results for this comparison suggest that when the stripline resonator is used, dielectric property measurements are not as accurate as magnetic property measurements, provided that a correction for demagnetization is made. The results are compared to 7 mm coaxial transmission line measurements which have an uncertainty of less than 10% for the relative permittivity, epsilon(r)' < 15. C1 Natl Inst Stand & Technol, Radio Frequency Technol Div, Boulder, CO 80303 USA. RP Jones, CA (reprint author), Natl Inst Stand & Technol, Radio Frequency Technol Div, 325 Broadway, Boulder, CO 80303 USA. NR 16 TC 14 Z9 14 U1 0 U2 4 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9456 J9 IEEE T INSTRUM MEAS JI IEEE Trans. Instrum. Meas. PD AUG PY 1999 VL 48 IS 4 BP 843 EP 848 DI 10.1109/19.779187 PG 6 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA 225HY UT WOS:000081953400011 ER PT J AU Armstrong, N Kalceff, W AF Armstrong, N Kalceff, W TI A maximum entropy method for determining column-length distributions from size-broadened X-ray diffraction profiles SO JOURNAL OF APPLIED CRYSTALLOGRAPHY LA English DT Article ID SMALL-ANGLE SCATTERING; IMAGE-RECONSTRUCTION; POWDER DIFFRACTION; RESOLUTION; SHAPE AB We present a novel application of the maximum entropy (MaxEnt) method for solving the double-inverse problems of removing instrument broadening from Xray diffraction profiles and calculating the column-length distribution of the crystallites. The MaxEnt approach is shown to have compelling advantages over the conventional methods it replaces: it is stable and robust, incorporates noise and a priori information into the solution, preserves positivity of the solution, and can be applied successively. We also show how uncertainties in the derived profiles and column distributions can be determined and used in subsequent calculations, including integral breadth, Fourier coefficients, column-length distributions and apparent particle sizes. Calculations are performed on simulated X-ray diffraction profiles for a range of particle sizes, with a detailed study of the sensitivity of the results to background-level estimates and the use of an incorrect instrument response function. C1 Univ Technol Sydney, Dept Appl Phys, Broadway, NSW 2007, Australia. RP Armstrong, N (reprint author), NIST, Div Ceram, Gaithersburg, MD 20899 USA. EM wkalceff@phys.uts.edu.au NR 38 TC 14 Z9 14 U1 0 U2 2 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 0021-8898 J9 J APPL CRYSTALLOGR JI J. Appl. Crystallogr. PD AUG 1 PY 1999 VL 32 BP 600 EP 613 DI 10.1107/S0021889899000692 PN 4 PG 14 WC Chemistry, Multidisciplinary; Crystallography SC Chemistry; Crystallography GA 225LW UT WOS:000081963900003 ER PT J AU Banta, RM Darby, LS Kaufmann, P Levinson, DH Zhu, CJ AF Banta, RM Darby, LS Kaufmann, P Levinson, DH Zhu, CJ TI Wind-flow patterns in the Grand Canyon as revealed by Doppler lidar SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID ROUGH URBAN SURFACE; TRIBUTARY VALLEY; MOUNTAIN VALLEY; DISPERSION; TERRAIN AB Many interesting how patterns were found in the Grand Canyon by a scanning Doppler lidar deployed to the south rim during the 1990 Wintertime Visibility Study. Three are analyzed in this study: 1) flow reversal in the canyon, where the Row in the canyon was in the opposite direction from the flow above the canyon rim; 2) under strong, gusty Row from the southwest, the how inside and above the canyon was from a similar direction and coupled; and 3) under light large-scale ambient flow, the lidar found evidence of local, thermally forced up- and down-canyon winds in the bottom of the canyon. On the days with flow reversal in the canyon, the strongest in-canyon flow response was found for days with northwesterly flow and a strong inversion at the canyon rim. The aerosol backscatter profiles were well mixed within the canyon but poorly mixed across the rim because of the inversion. The gusty southwest flow days showed strong evidence of vertical mixing across the rim both in the momentum and in the aerosol backscatter profiles, as one would expect in turbulent flow. The days with light ambient flow showed poor vertical mixing even inside the canyon, where the jet of down-canyon flow in the bottom of the canyon at night was often either cleaner or dirtier than the air in the upper portions of the canyon. In a case study presented, the light ambient flow regime ended with an intrusion of polluted, gusty, southwesterly flow. The polluted, high-backscatter air took several hours to mix into the upper parts of the canyon. An example is also given of high-backscatter air in the upper portions of the canyon being mixed rapidly down into a jet of cleaner air in the bottom of the canyon in just a few minutes. C1 NOAA, ERL, Environm Technol Lab, Boulder, CO 80303 USA. Univ Colorado, Cooperat Inst Res Atmospher Sci, Boulder, CO 80309 USA. RP Banta, RM (reprint author), NOAA, ERL, Environm Technol Lab, ET2,325 Broadway, Boulder, CO 80303 USA. RI Darby, Lisa/A-8037-2009; Kaufmann, Pirmin/C-4713-2012; Banta, Robert/B-8361-2008 OI Darby, Lisa/0000-0003-1271-0643; Kaufmann, Pirmin/0000-0002-0873-598X; NR 34 TC 36 Z9 36 U1 0 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 AUG PY 1999 VL 38 IS 8 BP 1069 EP 1083 DI 10.1175/1520-0450(1999)038<1069:WFPITG>2.0.CO;2 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 233BR UT WOS:000082406100004 ER PT J AU Kaufmann, P Whiteman, CD AF Kaufmann, P Whiteman, CD TI Cluster-analysis classification of wintertime wind patterns in the Grand Canyon region SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID CLIMATOLOGY; FIELDS AB Twelve typical wintertime wind patterns for the Grand Canyon region were derived from a two-stage cluster analysis wind-field classification scheme. The wind measurements were collected by a surface network of 15 stations deployed for a period of approximately three months. The wind patterns are strongly influenced by the complex terrain of the region. The analyses relate the wind patterns to meteorological conditions, providing insight into the physical processes generating the wind fields. Most patterns have a distinct diurnal cycle, caused by thermally induced winds near the ground. They provide evidence that thermally forced flows are important in winter and are not easily overridden by ambient flows. Some patterns differ primarily in the ratio of high- and low-elevation site wind speeds, indicating the importance of decoupling of the low-elevation winds in this basin area from the stronger ambient winds. C1 Univ Colorado, NOAA, Environm Technol Lab, CIRES, Boulder, CO 80309 USA. Pacific NW Lab, Richland, WA 99352 USA. RP Kaufmann, P (reprint author), Swiss Meteorol Inst, POB 514, CH-8044 Zurich, Switzerland. RI Kaufmann, Pirmin/C-4713-2012 OI Kaufmann, Pirmin/0000-0002-0873-598X NR 13 TC 34 Z9 35 U1 1 U2 5 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 AUG PY 1999 VL 38 IS 8 BP 1131 EP 1147 DI 10.1175/1520-0450(1999)038<1131:CACOWW>2.0.CO;2 PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 233BR UT WOS:000082406100008 ER PT J AU Liang, JK Huang, Q Santoro, A Liu, QL Chen, XL AF Liang, JK Huang, Q Santoro, A Liu, QL Chen, XL TI A neutron powder diffraction study of the system La-2(Co1-xFex)(16)Ti for x=0.0, 0.2, and 0.4 SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID UNIAXIAL MAGNETOCRYSTALLINE ANISOTROPY; INTERMETALLIC COMPOUNDS AB The nuclear and magnetic structures of La-2(Co1-xFex)(16)Ti have been studied by neutron powder diffraction for the compositions x=0.0,0.2,0.4. The compound crystallizes with the symmetry of space group m. Site occupancy results show significant departures from a purely statistical distribution, with the Ti atoms located in sites which interact weakly with La, and with the Co atoms occupying preferentially the sites with strong La interaction. These results are consistent with the enthalpies of formation of equiatomic alloys of rare earth and 3d elements. The spin ordering at all compositions and temperatures is ferromagnetic. At room temperature the moments are aligned along the c axis for the compositions x=0.0 and x=0.2, and form an angle of about 57 degrees with c for x=0.4. This tilt angle is a function of temperature and the moment is aligned along c at 11 K, moving gradually towards the a,b plane as the temperature increases. (C) 1999 American Institute of Physics. [S0021-8979(99)06015-6]. C1 Chinese Acad Sci, Inst Phys, Shenyang 110015, Peoples R China. Chinese Acad Sci, Ctr Condensed Matter Phys, Shenyang 110015, Peoples R China. Acad Sinica, Int Ctr Mat Phys, Shenyang 110015, Peoples R China. Natl Inst Stand & Technol, Ctr Neutron Res, Gaithersburg, MD 20899 USA. Univ Maryland, Dept Mat & Nucl Engn, College Pk, MD 20742 USA. RP Liang, JK (reprint author), Chinese Acad Sci, Inst Phys, Shenyang 110015, Peoples R China. RI LIU, Quanlin/E-2168-2016 OI LIU, Quanlin/0000-0003-3533-7140 NR 5 TC 2 Z9 4 U1 1 U2 4 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD AUG 1 PY 1999 VL 86 IS 3 BP 1226 EP 1229 DI 10.1063/1.370875 PG 4 WC Physics, Applied SC Physics GA 216TD UT WOS:000081458800010 ER PT J AU Ulbrich, CW Lee, LG AF Ulbrich, CW Lee, LG TI Rainfall measurement error by WSR-88D radars due to variations in Z-R law parameters and the radar constant SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article AB An investigation is made of the extent to which variations in Z-R (reflectivity factor-rainfall rate) relations can explain the systematically large offsets of radar-measured rainfall from rain gauge measurements as observed with some National Weather Service (NWS) WSR-88D radars. It is shown that theory predicts that the use by the NWS of the current default Z-R relation (Z = 300R(1.4)) should underestimate rainfall by about 25% in stratiform rain and overestimate it by about 33% in thunderstorm rain. Yet it is commonly observed that some WSR-88D radars systematically underestimate rainfall by a factor of 2 or more in stratiform rain and produce estimates of rainfall with acceptable accuracy for isolated thunderstorms. It is shown that variations in Z-R law parameters alone cannot explain these discrepancies,and it is proposed that their origin lies in a radar calibration offset. A comparison is made of reflectivity factors measured by the KGSP WSR-88D at Greer, South Carolina, with those determined from disdrometer measurements at the Clemson Atmospheric Research Laboratory. Comparisons for five storms find that the radar systematically underestimates the reflectivity factor by more than 3.5 dB. This offset of the radar-measured reflectivity factor below the disdrometer measurements accounts for the systematic factor of 2 underestimation for stratiform rain and the apparent acceptable accuracy for thunderstorms using the KGSP WSR-88D radar. The difference between the radar and disdrometer measurements of the reflectivity factor is interpreted as being due to a radar calibration offset. It is also proposed that the systematic differences observed with other WSR-88D radars may be the result of Similar calibration offsets. C1 Clemson Univ, Dept Phys & Astron, Clemson, SC 29634 USA. Natl Weather Serv Off, Greer, SC USA. RP Ulbrich, CW (reprint author), Clemson Univ, Dept Phys & Astron, Clemson, SC 29634 USA. NR 18 TC 59 Z9 60 U1 1 U2 7 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 1999 VL 16 IS 8 BP 1017 EP 1024 DI 10.1175/1520-0426(1999)016<1017:RMEBWR>2.0.CO;2 PG 8 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA 231EJ UT WOS:000082294900003 ER PT J AU Abdulagatov, IM Magomedov, UB AF Abdulagatov, IM Magomedov, UB TI Measurements of the thermal conductivity of aqueous CoCl2 solutions at pressures up to 100 MPa by the parallel-plate apparatus SO JOURNAL OF CHEMICAL ENGINEERING OF JAPAN LA English DT Article DE aqueous salt solution; cobalt chloride; high pressure; thermal conductivity; temperature; water ID HOT-WIRE METHOD; 473 K AB The thermal conductivity of H2O + CoCl2 solutions was measured over the temperature range 293 to 473 K using a parallel-plate apparatus. Data cover the pressure range from 0.1 to 100 MPa. Measurements were made on ten isotherms, namely: 293, 313, 333, 353, 373, 393, 413, 433, and 473 K. The concentrations studied were 2.5, 5, Ill, 15, 20, and 25 wt % CoCl2,. The uncertainty of thermal conductivity measurements was estimated to be +/-1.6%. The pressure effect on thermal conductivity behavior was similar for H2O and H2O + CoCl2. In the temperature range of our experiments, isotherms of thermal conductivity were almost linear function of pressure at all temperatures for each concentrations. Along each isobar a given concentration the thermal-conductivity of H2O + CoCl2 solutions exhibits a maximum at temperatures between 405 and 419 K. The measured values of thermal conductivity are compared with the experimental and correlation results of other investigators. A new correlation which yields the correct temperature, pressure, and concentration behavior of thermal conductivity is proposed. This maximum is displaced to higher temperature when the pressure is increased at each compositions. For fixed pressure the maximum is displaced to Lower temperature when the composition is increased. C1 Russian Acad Sci, Dagestan Sci Ctr, Inst Geothermal Res, Dagestan, Russia. RP Abdulagatov, IM (reprint author), Natl Inst Stand & Technol, Phys & Chem Properties Div, 325 Broadway, Boulder, CO 80303 USA. NR 24 TC 11 Z9 11 U1 0 U2 2 PU SOC CHEMICAL ENG JAPAN PI BUNKYO KU TOKYO PA KYORITSU BUILDING 4-16-19 KOHINATA, BUNKYO KU TOKYO, 112, JAPAN SN 0021-9592 J9 J CHEM ENG JPN JI J. Chem. Eng. Jpn. PD AUG PY 1999 VL 32 IS 4 BP 465 EP 471 DI 10.1252/jcej.32.465 PG 7 WC Engineering, Chemical SC Engineering GA 230EU UT WOS:000082239500013 ER PT J AU Zhang, KJ Briggs, ME Gammon, RW Sengers, JV Douglas, JF AF Zhang, KJ Briggs, ME Gammon, RW Sengers, JV Douglas, JF TI Thermal and mass diffusion in a semidilute good solvent-polymer solution SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID DYNAMIC LIGHT-SCATTERING; MOLECULAR-WEIGHT; CONCENTRATION-DEPENDENCE; TRANSLATIONAL DIFFUSION; OPTICAL MEASUREMENT; FLEXIBLE POLYMERS; SORET COEFFICIENT; REFRACTIVE-INDEX; DILUTE-SOLUTION; POLYSTYRENES AB The Soret coefficient S-T and collective (mass) diffusion coefficient D-c of polystyrene dissolved in the good-solvent toluene has been measured over a range of concentrations and molecular masses with an optical beam-deflection method. Our measurements indicate that S-T scales inversely with the polymer translational diffusion coefficient in dilute solutions, exhibits a power-law scaling with polymer concentration, and an independence of polymer molecular mass in semidilute solutions. These findings are consistent with the known scaling of 1/D-c in dilute and semidilute polymer solutions, the relative insensitivity of the thermal-diffusion coefficient D-th of polystyrene in toluene to polymer concentration, and the relation S-T=D-th/D-c from irreversible thermodynamics. We are able to represent our S-T and D-c data by theoretically motivated reduced-concentration master curves, but the concentration-molecular mass scaling variables are found to be different for each transport property, a result contrary to theoretical expectations. However, the asymptotic concentration scaling exponents deduced from these data fits are compatible with de Gennes' scaling arguments for D-c and with modern estimates of the chain-size exponent nu for swollen polymers in good solvents. (C) 1999 American Institute of Physics. [S0021-9606(99)51128-8]. C1 Univ Maryland, Inst Phys Sci & Technol, College Pk, MD 20742 USA. Univ Maryland, Dept Chem Engn, College Pk, MD 20742 USA. NIST, Mat Sci & Engn Lab, Div Polymers, Gaithersburg, MD 20899 USA. RP Zhang, KJ (reprint author), Elect Data Syst, Human Resources Grp, 13600 EDS Dr, Herndon, VA 20171 USA. NR 44 TC 88 Z9 88 U1 0 U2 10 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD AUG 1 PY 1999 VL 111 IS 5 BP 2270 EP 2282 DI 10.1063/1.479498 PG 13 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 220ZA UT WOS:000081698700056 ER PT J AU Stouffer, RJ Manabe, S AF Stouffer, RJ Manabe, S TI Response of a coupled ocean-atmosphere model to increasing atmospheric carbon dioxide: Sensitivity to the rate of increase SO JOURNAL OF CLIMATE LA English DT Article ID FRESH-WATER INPUT; THERMOHALINE CIRCULATION; CLIMATE RESPONSE; TRANSIENT RESPONSES; SULFATE AEROSOLS; GRADUAL CHANGES; HEAT-TRANSPORT; CO2; SEA; VARIABILITY AB The influence of differing rates of increase of the atmospheric CO2 concentration on the climatic response is investigated using a coupled ocean-atmosphere model. Five transient integrations are performed each using a different constant exponential rate of CO2 increase ranging from 4% yr(-1) to 0.25% yr(-1). By the time of CO2 doubling, the surface air temperature response in all the transient integrations is locally more than 50% and globally more than 35% of the equilibrium response. The land-sea contrast in the warming, which is evident in the equilibrium results, is larger in all the transient experiments. The land-sea difference in the response increases with the rate of increase in atmospheric CO2 concentration. The thermohaline circulation (THC) weakens in response to increasing atmospheric CO2 concentration in all the transient integrations, confirming earlier work. The results also indicate that the slower the rate of increase, the larger the weakening of the THC by the time of doubling. Two of the transient experiments are continued beyond the time of CO2 doubling with the CO2 concentration maintained at that level. The amount of weakening of the THC after the CO2 stops increasing is smaller in the experiment with the slower rate of CO2 increase, indicating that the coupled system has more time to adjust to the forcing when the rate of CO2 increase is slower After a period of slow overturning, the THC gradually recovers and eventually regains the intensity found in the control integration, so that the equilibrium THC is very similar in the control and doubled CO2 integrations. Considering only the sea level changes due to the thermal expansion of seawater, the integration with the slowest rate of increase in CO2 concentration (i.e., 0.25% yr(-1)) has the largest globally averaged sea level rise by the time of CO2 doubling (about 42 cm). However, only a relatively small fraction of the equilibrium sea level rise of 1.9 m is realized by the time of doubling in all the transient integrations. This implies that sea level continues to rise long after the CO2 concentration stops increasing, as the warm anomaly penetrates deeper into the ocean. C1 NOAA, Geophys Fluid Dynam Lab, Princeton, NJ 08542 USA. Inst Global Change Res, Frontier Res Syst Earth Sci, Tokyo, Japan. RP Stouffer, RJ (reprint author), NOAA, Geophys Fluid Dynam Lab, Forrestal Campus,US Route 1,POB 308, Princeton, NJ 08542 USA. NR 40 TC 107 Z9 109 U1 1 U2 5 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8755 J9 J CLIMATE JI J. Clim. PD AUG PY 1999 VL 12 IS 8 BP 2224 EP 2237 DI 10.1175/1520-0442(1999)012<2224:ROACOA>2.0.CO;2 PN 1 PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 232HA UT WOS:000082364100006 ER PT J AU Hall, A Manabe, S AF Hall, A Manabe, S TI The role of water vapor feedback in unperturbed climate variability and global warming SO JOURNAL OF CLIMATE LA English DT Article ID GENERAL-CIRCULATION MODEL; OCEAN-ATMOSPHERE MODEL; NATURAL VARIABILITY; COUPLED MODEL; TEMPERATURE; CO2 AB To understand the role of water vapor feedback in unperturbed surface temperature variability, a version of the Geophysical Fluid Dynamics Laboratory coupled ocean-atmosphere model is integrated for 1000 yr in two configurations, one with water vapor feedback and one without. For all spatial scales, the model with water vapor feedback has more low-frequency (timescale greater than or equal to 2 yr) surface temperature variability than the one without. Thus water vapor feedback is positive in the context of the model's unperturbed variability. In addition, water vapor feedback is more effective the longer the timescale of the surface temperature anomaly and the larger its spatial scale. To understand the role of water vapor feedback in global warming, two 500-yr integrations were also performed in which CO2 was doubled in bath model configurations. The final surface global warming in the model with water vapor feedback is 3.38 degrees C, while in the one without it is only 1.05 degrees C. However, the model's water vapor feedback has a larger impact on surface warming in response to a doubling of CO2 than it does on internally generated, low-frequency, global-mean surface temperature anomalies. Water vapor feedback's strength therefore depends on the type of temperature anomaly it affects. The authors found that the degree to which a surface temperature anomaly penetrates into the troposphere is a critical factor in determining the effectiveness of its associated water vapor feedback. The more the anomaly penetrates, the stronger the feedback. It is also shown that the apparent impact of water vapor feedback is altered by other feedback mechanisms, such as albedo and cloud feedback. The sensitivity of the results to this fact is examined. Finally, the authors compare the local and global-mean surface temperature time series from both unperturbed variability experiments to the observed record. The experiment without water vapor feedback does not have enough global-scale variability to reproduce the magnitude of the variability in the observed global-mean record, whether or not one removes the warming trend observed over the past century. In contrast, the amount of variability in the experiment with water vapor feedback is comparable to that of the global mean record, provided the observed warming trend is removed. Thus, the authors are unable to simulate the observed levels of variability without water vapor feedback. C1 Princeton Univ, Atmospher & Ocean Sci Program, Princeton, NJ 08544 USA. Geophys Fluid Dynam Lab, Princeton, NJ USA. RP Hall, A (reprint author), Columbia Univ, Lamont Doherty Earth Observ, Oceanog Bldg,Room 103,POB 1000,61 Route 9W, Palisades, NY 10964 USA. RI Hall, Alex/D-8175-2014 NR 26 TC 65 Z9 69 U1 3 U2 18 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 PY 1999 VL 12 IS 8 BP 2327 EP 2346 DI 10.1175/1520-0442(1999)012<2327:TROWVF>2.0.CO;2 PN 1 PG 20 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 232HA UT WOS:000082364100011 ER PT J AU Larson, K Hartmann, DL Klein, SA AF Larson, K Hartmann, DL Klein, SA TI The role of clouds, water vapor, circulation, and boundary layer structure in the sensitivity of the tropical climate SO JOURNAL OF CLIMATE LA English DT Article ID SEA-SURFACE TEMPERATURE; EARTHS ENERGY-BALANCE; EQUATORIAL PACIFIC; OCEAN; THERMOSTAT; ATMOSPHERE; GREENHOUSE; CONVECTION; PARAMETERIZATION; SATELLITE AB The physical mechanisms that affect the tropical sea surface temperature (SST) are investigated using a two-box equilibrium model of the Tropics. One box represents the convecting, warm SST, high humidity region of the Tropics. and the other box represents the subsidence region with low humidity, boundary layer clouds, and cooler SST. The two regions communicate by energy and moisture fluxes that are proportional to the strength of the overturning circulation that couples the two regions. The boundary layer properties in the subsiding region ore predicted with a mixing line model. Humidity above the inversion in the subsiding region is predicted from moisture conservation. The humidity above the inversion in the subsiding region increases rapidly with temperature, but this has less effect on the sensitivity than expected, because the inversion lowers as the humidity above the inversion is increased. Some of the Increased greenhouse effect of the free troposphere can be offset by decreased greenhouse effect of the boundary layer. Increasing the area of the warm. convective region increases the SSTs, because of the greenhouse effect of the greater upper-tropospheric water vapor in the convective region. The circulation strength is constrained by radiative cooling in the cold pool. The strength of the circulation decreases with increasing convective area, because the increase in dry static stability overwhelms the increase in cooling rate. Although they have strong individual effects on longwave and shortwave radiation, high clouds in the convective region do not affect the tropical SSTs strongly, because their net radiative forcing at the top of the atmosphere is small. Low clouds in the subsidence region have a strong cooling affect on the tropical SST, because they strongly reduce net radiative heating at the top of the atmosphere. A negative feedback is produced if the low clouds are predicted from the observed relationship between stratus cloud amount and lower-tropospheric stability. C1 Univ Washington, Dept Atmospher Sci, Seattle, WA 98195 USA. Princeton Univ, NOAA, Geophys Fluid Dynam Lab, Princeton, NJ 08544 USA. RP Larson, K (reprint author), Univ Washington, Dept Atmospher Sci, POB 351640, Seattle, WA 98195 USA. RI Klein, Stephen/H-4337-2016 OI Klein, Stephen/0000-0002-5476-858X NR 39 TC 60 Z9 62 U1 0 U2 5 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8755 J9 J CLIMATE JI J. Clim. PD AUG PY 1999 VL 12 IS 8 BP 2359 EP 2374 DI 10.1175/1520-0442(1999)012<2359:TROCWV>2.0.CO;2 PN 1 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 232HA UT WOS:000082364100013 ER PT J AU Dai, A Trenberth, KE Karl, TR AF Dai, A Trenberth, KE Karl, TR TI Effects of clouds, soil moisture, precipitation, and water vapor on diurnal temperature range SO JOURNAL OF CLIMATE LA English DT Article ID SURFACE-TEMPERATURE; MINIMUM TEMPERATURE; GLOBAL EMISSIONS; GREENHOUSE GASES; CLIMATE-CHANGE; SULFUR-OXIDES; UNITED-STATES; LAND AREAS; MAXIMUM; TRENDS AB The diurnal range of surface air temperature (DTR) has decreased worldwide during the last 4-5 decades and changes in cloud cover are often cited as one of the likely causes. To determine how clouds and moisture affect DTR physically on daily bases, the authors analyze the 30-min averaged data of surface meteorological variables and energy fluxes from the the First International Satellite Land Surface Climatology Project Field Experiment and the synoptic weather reports of 1980-1991 from about 6500 stations worldwide. The statistical relationships are also examined more thoroughly in the historical monthly records of DTR, cloud cover, precipitation, and streamflow of this century. It is found that clouds, combined with secondary damping effects from soil moisture and precipitation, can reduce DTR by 25%-50% compared with clear-sky days over most land areas; while atmospheric water vapor increases both nighttime and daytime temperatures and has small effects on DTR. Clouds, which largely determine the geographic patterns of DTR, greatly reduce DTR by sharply decreasing surface solar radiation while soil moisture decreases DTR by increasing daytime surface evaporative cooling. Clouds with low bases are most efficient in reducing the daytime maximum temperature and DTR mainly because they are very effective in reflecting the Sunlight, while middle and high clouds have only moderate damping effects on DTR. The DTR reduction by clouds is largest in warm and dry seasons such as autumn over northern midlatitudes when latent heat release is limited by the soil moisture content. The net effects of clouds on the nighttime minimum temperature is small except in the winter high latitudes where the greenhouse warming effect of clouds exceeds their solar cooling effect. The historical records of DTR of the twentieth century covary inversely with cloud cover and precipitation on interannual to multidecadal timescales over the United States, Australia, midlatitude Canada, and former U.S.S.R., and up to 80% of the DTR variance can be explained by the cloud and precipitation records. Given the strong damping effect of clouds on the daytime maximum temperature and DTR, the well-established worldwide asymmetric trends of the daytime and nighttime temperatures and the DTR decreases during the last 4-5 decades are consistent with the reported increasing trends in cloud cover and precipitation over many land areas and support the notion that the hydrologic cycle has intensified. C1 Natl Ctr Atmospher Res, Boulder, CO 80307 USA. NOAA, Natl Climat Data Ctr, Asheville, NC USA. RP Dai, A (reprint author), Natl Ctr Atmospher Res, POB 3000, Boulder, CO 80307 USA. RI Trenberth, Kevin/A-5683-2012; Dai, Aiguo/D-3487-2009 OI Trenberth, Kevin/0000-0002-1445-1000; NR 39 TC 338 Z9 353 U1 15 U2 85 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 PY 1999 VL 12 IS 8 BP 2451 EP 2473 DI 10.1175/1520-0442(1999)012<2451:EOCSMP>2.0.CO;2 PN 2 PG 23 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 232MM UT WOS:000082374600001 ER PT J AU Kunkel, KE Andsager, K Easterling, DR AF Kunkel, KE Andsager, K Easterling, DR TI Long-term trends in extreme precipitation events over the conterminous United States and Canada SO JOURNAL OF CLIMATE LA English DT Article ID NORTH-AMERICA; FLOODS; VARIABILITY; TEMPERATURE; FREQUENCY; SNOWFALL AB This paper describes the results of an analysis of trends in short duration (1-7 days) extreme precipitation events that have a recurrence interval of 1 yr or longer for stations in the United States and Canada. This definition of extreme precipitation was chosen because such events are highly correlated with hydrologic flooding in some U.S. regions, The dominant temporal characteristic of a national event composite index is significant low-frequency variability. There were lengthy periods of a below-average number of events in the 1930s and 1950s and an above-average number of events in the early 1940s, early 1980s, and 1990s. Regional variations often differ substantially from the national composite. A simple linear analysis indicates that the overall trend covering the period 1931-96 has been upward at a highly statistically significant rate over the southwest United States and in a broad region from the central Great Plains across the middle Mississippi River and southern Great Lakes basins. The national trend for the United States is upward at a rate of 3% decade(-1) for the period 1931-96. While the annual trend for Canada is upward for the period 1951-93, it is not statistically significant. Although the high statistical significance of the results is partially a consequence of the low frequency during the 1930s and 1950s located in the first half of the record, the latter half of the record exhibits an upward trend nearly identical to the entire record. However, an analysis of a 101-yr record of midwestern stations shows that heavy precipitation event frequencies around the turn of the twentieth century (1896-1906) were higher than for other periods of comparable length, except for 1986-96. Although data were not available in digital form to extend the analysis back to 1896 for the entire United Stales, the midwestern analysis shows that interpretation of the recent upward trends must account for the possibility of significant natural forcing of variability on century timescales. C1 Illinois State Water Survey, Champaign, IL 61820 USA. Natl Climat Data Ctr, Asheville, NC USA. RP Kunkel, KE (reprint author), Illinois State Water Survey, 2204 Griffith Dr, Champaign, IL 61820 USA. RI Kunkel, Kenneth/C-7280-2015 OI Kunkel, Kenneth/0000-0001-6667-7047 NR 25 TC 236 Z9 251 U1 8 U2 46 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 PY 1999 VL 12 IS 8 BP 2515 EP 2527 DI 10.1175/1520-0442(1999)012<2515:LTTIEP>2.0.CO;2 PN 2 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 232MM UT WOS:000082374600005 ER PT J AU Hendon, HH Zhang, CD Glick, JD AF Hendon, HH Zhang, CD Glick, JD TI Interannual variation of the Madden-Julian oscillation during austral summer SO JOURNAL OF CLIMATE LA English DT Article ID OUTGOING LONGWAVE RADIATION; 40-50 DAY OSCILLATION; EMPIRICAL ORTHOGONAL FUNCTIONS; PLANETARY-SCALE CIRCULATIONS; TROPICAL CONVECTION; SEASONAL-VARIATIONS; FLUCTUATIONS; VARIABILITY; MONSOON; TEMPERATURE AB Interannual variability of the Madden-Julian oscillation (MJO). the dominant mode of intraseasonal variability in the Tropics, is investigated during the extended austral summer season November-March, which is when the MJO is most prominent. Indexes of the level of MJO activity are developed using outgoing longwave radiation and zonal wind analyses at 850 mb for 1974-98. Based on these indexes, interannual variations in the level of MJO activity are found to be primarily associated with changes in the number of discrete MJO events each year and with changes in the intensity of intraseasonal convection across the Indian and western Pacific Oceans, where the MJO is normally prominent. An eastward shift of MJO activity east of the date line does occur during El Nino events. However, the overall level of MJO activity is found to be uncorrelated with El Nine, except during exceptional warm events when MJO activity is diminished, The level of MJO activity is shown to be weakly related to sea surface temperature anomalies in the equatorial Indian and western Pacific Oceans, but the weak correlations imply that much of the year-to-year variability of the MJO is internally generated, independent of any slowly varying boundary forcing. Such year-to-year variations of the intensity of the MJO are, however, associated with changes in the distribution of seasonal mean convection across the tropical Indian and western Pacific Oceans. This interannual variation of convection unrelated to SST variability may thus act as a limit to seasonal predictions that rely heavily on equatorial Pacific SST anomalies. C1 NOAA, CIRES, Climate Diagnost Ctr, Boulder, CO 80303 USA. Univ Miami, Rosenstiel Sch Marine & Atmospher Sci, Div Meteorol & Phys Oceanog, Miami, FL 33149 USA. RP Hendon, HH (reprint author), NOAA, CIRES, Climate Diagnost Ctr, Boulder, CO 80303 USA. NR 30 TC 169 Z9 184 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 AUG PY 1999 VL 12 IS 8 BP 2538 EP 2550 DI 10.1175/1520-0442(1999)012<2538:IVOTMJ>2.0.CO;2 PN 2 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 232MM UT WOS:000082374600007 ER PT J AU Angell, JK AF Angell, JK TI Variation with height and latitude of radiosonde temperature trends in North America, 1975-94 SO JOURNAL OF CLIMATE LA English DT Article ID OZONE DEPLETION; STRATOSPHERE; WINTER; MSU AB Based on the 120-station North American radiosonde network, temperature trends for 100-50-mb (low stratosphere), 300-100-mb (tropopause), and 850-300-mb (troposphere) layers, and Earth's surface, are evaluated for six 10 degrees latitude bands extending from 20 degrees-30 degrees N to 70 degrees-80 degrees N for the 20-yr interval 1975-94. Confidence estimates are indicated by two standard errors of the least squares regression. In the average for the six latitude bands, the 100-50-mb annual temperature trend is -0.5 degrees C decade(-1) and the 850-300-mb trend is 0.2 degrees C decade(-1). In spring at 70 degrees-80 degrees N, the 100-50-mb and 300-100-mb layers cool by almost 2 degrees C decade(-1). The 300-100-mb layer cools by 0.7 degrees C decade(-1) relative to the 850-300-mb layer at 70 degrees-80 degrees N, but the two layers have the same warming trend at 20 degrees-30 degrees N, indicating the transition from the 300-100-mb layer being mostly in the stratosphere in polar regions to mostly in the troposphere in the northern subtropics. The surface warms much more than the troposphere at 70 degrees-80 degrees N (showing that surface temperature trends are not representative of tropospheric trends in polar regions) and slightly more at 20 degrees-30 degrees N, bur surface warming is less than tropospheric warming in the 40 degrees-70 degrees N belt. Ar the surface at the radiosonde sites the 1200 UTC (morning) temperature cools relative to the 0000 UTC (evening) temperature by 0.05 degrees C per decade on average, but the 850-300-mb temperature trends at 0000 UTC and 1200 UTC are essentially the same. The 0.7 degrees C decade(-1) cooling of low stratosphere relative to troposphere increases to 0.9 degrees C decade(-1) when adjustment is made for the stratospheric warming and tropospheric cooling following El Chichon and Pinatubo eruptions. The temperature trends obtained from 11 North American radiosonde stations in a 63-station global network agree well with the trends based on the entire 120-station network, and the latter are fairly representative of zonally averaged trends based on the 63-station network and microwave sounding unit data, Comparison with Canadian ozonesonde data shows that. in the low stratosphere and high troposphere during 1975-94, a decrease in temperature of 1 degrees C decade(-1) was associated with a decrease in ozone of about 10% decade(-1). C1 NOAA, Air Resources Lab, Silver Spring, MD 20910 USA. RP Angell, JK (reprint author), OAR, REAR, 1315 East West Highway, Silver Spring, MD 20910 USA. NR 19 TC 11 Z9 11 U1 0 U2 2 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 PY 1999 VL 12 IS 8 BP 2551 EP 2561 DI 10.1175/1520-0442(1999)012<2551:VWHALO>2.0.CO;2 PN 2 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 232MM UT WOS:000082374600008 ER PT J AU Santhiya, D Subramanian, S Natarajan, KA Malghan, SG AF Santhiya, D Subramanian, S Natarajan, KA Malghan, SG TI Surface chemical studies on the competitive adsorption of poly(acrylic acid) and poly(vinyl alcohol) onto alumina SO JOURNAL OF COLLOID AND INTERFACE SCIENCE LA English DT Article DE alpha-alumina; poly(acrylic acid); poly(vinyl alcohol); adsorption; electrokinetics ID POLYACRYLIC-ACID; AGGREGATION FRAGMENTATION; COLLOIDAL ALUMINA; POLYELECTROLYTE; MIXTURES; IONS; PH AB The adsorption of poly(acrylic acid) (PAA) and poly(vinyl alcohol) (PVA) onto alumina has been studied as a function of pH, both individually and in the presence of each other. The adsorption density of PAA is found to decrease with an increase of pH while that of PVA shows the opposite trend. In a binary system containing PAA and PVA, the presence of PVA does not affect the adsorption of PAA onto alumina, but the addition of PAA diminishes the adsorption of PVA in the pH range investigated. The adsorption isotherm of PAA at acidic pH exhibits high-affinity Langmuirian behavior. The isotherms for PVA appear rounded and are of the low-affinity type, Once again the adsorption isotherms of PAA remain unaltered in the presence of PVA whereas those of PVA are significantly affected resulting in a lowering of the adsorption density consequent to PAA addition. A variation in the sequence of addition of PAA and PVA does not affect the adsorption behavior of either of the polymers, The electrokinetic behavior of alumina with PAA is hardly influenced by the addition of PVA, On the other hand, the electrophoretic mobility of alumina in the presence of PVA is significantly altered in the presence of PAA and closely resembles the trend observed with PAA alone. Desorption studies reveal that over 80% of PVA could be desorbed in the pH range 3-9 whereas in the case of PAA, the percent desorption increases from 20 to about 70% as the pH is increased from about 3 to 8. Solution conductivity tests confirm interaction of aluminum species and PAA in the bulk solution. FTIR spectroscopic data provide evidence in support of hydrogen bonding and chemical interaction in the case of the PAA-alumina system and hydrogen bonding with respect to the PVA-alumina interaction. (C) 1999 Academic Press. C1 Indian Inst Sci, Dept Met, Bangalore 560012, Karnataka, India. Natl Inst Stand & Technol, Div Ceram, Gaithersburg, MD 20899 USA. RP Malghan, SG (reprint author), Indian Inst Sci, Dept Met, Bangalore 560012, Karnataka, India. NR 38 TC 85 Z9 89 U1 2 U2 30 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0021-9797 J9 J COLLOID INTERF SCI JI J. Colloid Interface Sci. PD AUG 1 PY 1999 VL 216 IS 1 BP 143 EP 153 DI 10.1006/jcis.1999.6289 PG 11 WC Chemistry, Physical SC Chemistry GA 220RF UT WOS:000081680700018 ER PT J AU Jin, M Fread, DL AF Jin, M Fread, DL TI 1D modeling of mud/debris unsteady flows SO JOURNAL OF HYDRAULIC ENGINEERING-ASCE LA English DT Article ID OPEN-CHANNEL; DEBRIS-FLOW AB The National Weather Service 1D dynamic flood routing model FLDWAV is enhanced to include capability of modeling mud/debris unsteady flows by including an additional friction slope term in the momentum equation of the Saint-Venant equations. Three techniques are incorporated into the model to determine the mud/debris related friction slope term due to the internal viscous dissipation of non-Newtonian fluids and granular sliding friction of coarse-grained debris surges. These techniques are tested and some computational results are compared with observed field data and experimental data. C1 NOAA, Natl Weather Serv, Hydrol Res Lab, Ofc Hydro, Silver Spring, MD 20910 USA. RP Jin, M (reprint author), NOAA, Natl Weather Serv, Hydrol Res Lab, Ofc Hydro, 1325 East West Hwy, Silver Spring, MD 20910 USA. NR 22 TC 21 Z9 23 U1 0 U2 7 PU ASCE-AMER SOC CIVIL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2398 USA SN 0733-9429 J9 J HYDRAUL ENG-ASCE JI J. Hydraul. Eng.-ASCE PD AUG PY 1999 VL 125 IS 8 BP 827 EP 834 DI 10.1061/(ASCE)0733-9429(1999)125:8(827) PG 8 WC Engineering, Civil; Engineering, Mechanical; Water Resources SC Engineering; Water Resources GA 218CB UT WOS:000081534700003 ER PT J AU Knopp, KJ Christensen, DH Vander Rhodes, G Pomeroy, JM Goldberg, BB Unlu, MS AF Knopp, KJ Christensen, DH Vander Rhodes, G Pomeroy, JM Goldberg, BB Unlu, MS TI Spatio-spectral mapping of multimode vertical cavity surface emitting lasers SO JOURNAL OF LIGHTWAVE TECHNOLOGY LA English DT Article DE microscopy; near field; spectral spatial mapping; transverse modes; vertical cavity surface emitting laser (VCSEL); mapping ID VCSELS; MICROSCOPY AB This paper reports the spatial and spectral characteristics of multimode vertical cavity surface emitting laser (VCSEL) emission using near field scanning optical microscopy (NSOM), We have investigated 15 mu m diameter proton implanted 850 nm devices used in 2 Gb/s multimode fiber optic links, We have studied their near field spatial distribution of intensity and the lasing wavelengths of their transverse modes. False colored images were created to portray relative intensity, and spatial distribution information for each transverse mode. Correlation with shear force data allowed mapping of the optical distributions to topographical features of the device. Lasing filaments were observed at high drive currents. Spatially overlapping transverse modes were observed to compete for available gain while spatially isolated modes coexisted. C1 Natl Inst Stand & Technol, Boulder, CO 80303 USA. Boston Univ, Dept Phys, Boston, MA 02215 USA. Boston Univ, Dept Elect & Comp Engn, Boston, MA 02215 USA. Boston Univ, Photon Ctr, Boston, MA 02215 USA. RP Knopp, KJ (reprint author), Natl Inst Stand & Technol, MS 815-04, Boulder, CO 80303 USA. RI Unlu, Selim/B-4244-2013 NR 15 TC 15 Z9 15 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0733-8724 J9 J LIGHTWAVE TECHNOL JI J. Lightwave Technol. PD AUG PY 1999 VL 17 IS 8 BP 1429 EP 1435 DI 10.1109/50.779165 PG 7 WC Engineering, Electrical & Electronic; Optics; Telecommunications SC Engineering; Optics; Telecommunications GA 224FF UT WOS:000081886200018 ER PT J AU Celinski, Z Lucic, D Cramer, N Camley, RE Goldfarb, RB Skrzypek, D AF Celinski, Z Lucic, D Cramer, N Camley, RE Goldfarb, RB Skrzypek, D TI Exchange biasing in ferromagnet/antiferromagnet Fe/KMnF3 SO JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS LA English DT Article DE exchange biasing ID PHASE-TRANSITIONS; KMN1-XNIXF3; KMNF3 AB A new ferromagnet/antiferromagnet bilayer system, Fe/KMnF3, exhibits interesting interfacial exchange properties. The bulk antiferromagnet KMnF3 has three possible magnetic states: paramagnetic, antiferromagnetic, and weakly ferromagnetic spin-canted. Consequently, the exchange, anisotropy in Fe/KMnF3 is unusual. We examine the exchange bias in Fe/KMnF3 as a function of the magnetic state. Monocrystalline Fe(0 0 1) and polycrystalline Fe films, 3 nm thick, were grown epitaxially on Ag(0 0 1) templates on GaAs(0 0 1) substrates. Epitaxial KMnF3 was then grown an both the single-crystal and polycrystal Fe. We measured the low-field, zero-held-cooled and field-cooled magnetizations as functions of temperature. The zero-held-cooled single-crystal Fe magnetization is greatly reduced at liquid-helium temperatures. We see the influence of the transition from the antiferromagnetic to the spin-canted stale on the exchange coupling. The blocking temperature is close to the Neel temperature (89 K). From the shift in the hysteresis loop, we estimate the strength of the interfacial exchange coupling to be 4.5 x 10(-5) J/m(2). (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Colorado, Dept Phys, Colorado Springs, CO 80918 USA. Natl Inst Stand & Technol, Div Electromagnet Technol, Boulder, CO 80303 USA. Silesian Univ, Inst Phys, PL-40007 Katowice, Poland. RP Celinski, Z (reprint author), Univ Colorado, Dept Phys, Colorado Springs, CO 80918 USA. RI Goldfarb, Ronald/A-5493-2011 OI Goldfarb, Ronald/0000-0002-1942-7974 NR 11 TC 1 Z9 1 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0304-8853 J9 J MAGN MAGN MATER JI J. Magn. Magn. Mater. PD AUG PY 1999 VL 202 IS 2-3 BP 480 EP 484 DI 10.1016/S0304-8853(99)00364-9 PG 5 WC Materials Science, Multidisciplinary; Physics, Condensed Matter SC Materials Science; Physics GA 220TK UT WOS:000081683400027 ER PT J AU Ehlen, MA AF Ehlen, MA TI Life-cycle costs of fiber-reinforced-polymer bridge decks SO JOURNAL OF MATERIALS IN CIVIL ENGINEERING LA English DT Article AB Fiber-reinforced-polymer (FRP) composites are currently being developed and used in bridge decks. This report examines the Life-cycle cost-effectiveness of three FRP bridge decks, using a life-cycle cost method specifically tailored for comparing new materials with conventional ones. The method includes a cost classification scheme for capturing all project-related costs and for comparing the cost advantages and disadvantages of different materials. The uncertainty of new-material costs is assessed using the Monte Carlo simulations. Analysis indicates that one of the FRP decks is life-cycle cost-effective for a particular class of bridges and traffic levels. C1 Natl Inst Stand & Technol, Ofc Appl Econ Build & Fire Res Lab, Gaithersburg, MD 20899 USA. RP Ehlen, MA (reprint author), Natl Inst Stand & Technol, Ofc Appl Econ Build & Fire Res Lab, Gaithersburg, MD 20899 USA. NR 5 TC 28 Z9 28 U1 0 U2 7 PU ASCE-AMER SOC CIVIL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2398 USA SN 0899-1561 J9 J MATER CIVIL ENG JI J. Mater. Civ. Eng. PD AUG PY 1999 VL 11 IS 3 BP 224 EP 230 DI 10.1061/(ASCE)0899-1561(1999)11:3(224) PG 7 WC Construction & Building Technology; Engineering, Civil; Materials Science, Multidisciplinary SC Construction & Building Technology; Engineering; Materials Science GA 217QT UT WOS:000081511000006 ER PT J AU Wilbert, MC Delagah, S Pellegrino, J AF Wilbert, MC Delagah, S Pellegrino, J TI Variance of streaming potential measurements SO JOURNAL OF MEMBRANE SCIENCE LA English DT Article DE cellulose acetate membrane; streaming potential; zeta potential; membrane potentials ID ULTRAFILTRATION MEMBRANES; NANOFILTRATION MEMBRANES; SURFACE; CHARGE; MODEL AB We evaluated sources of variance in the measurement of the surface streaming potential of flat sheet specimens of cellulose di/triacetate membranes with a commercial electrokinetic analyzer. Two measurement methods were evaluated: the instrument's standard operating procedure, which continuously ramps the flow past the specimen, and a modified procedure that periodically stepped the flow rate and required manual calculation of zeta potential from the archived pressure and streaming potential data. Our study indicated that the kinetics of equilibration between electrolyte, electrodes, and membrane has the greatest impact on measurement uncertainty of any method used. An optimized protocol was developed for each method and the type A uncertainty (standard deviation) for the data collected using the optimized, modified procedure was one-third the value obtained using the optimized, standard procedure. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Natl Inst Stand & Technol, Boulder, CO 80303 USA. US Bur Reclamat, Denver, CO 80225 USA. RP Pellegrino, J (reprint author), Natl Inst Stand & Technol, 325 Broadway, Boulder, CO 80303 USA. OI PELLEGRINO, JOHN/0000-0001-7749-5003 NR 18 TC 40 Z9 41 U1 4 U2 15 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 1 PY 1999 VL 161 IS 1-2 BP 247 EP 261 PG 15 WC Engineering, Chemical; Polymer Science SC Engineering; Polymer Science GA 218LF UT WOS:000081553500022 ER PT J AU Meyer, A Wuttke, J Petry, W AF Meyer, A Wuttke, J Petry, W TI Two-step relaxation in a viscous metallic liquid SO JOURNAL OF NON-CRYSTALLINE SOLIDS LA English DT Article; Proceedings Paper CT 10th International Conference on Liquid and Amorphous Metal (LAM-10) CY AUG 30-SEP 04, 1998 CL UNIV DORTMUND, DORTMUND, GERMANY HO UNIV DORTMUND ID GLASS-TRANSITION; MELT; VISCOSITY; DIFFUSION AB We have studied the microscopic dynamics of the bulk glass forming alloy Zr46.8Ti8.2Cu7.5Ni10Be27.5 with quasi-elastic neutron scattering. In contrast to simple metals the equilibrium liquid has a two-step structural relaxation as do other liquids in their supercooled state. The fast beta-relaxation is in quantitative agreement with the scaling function of mode-coupling theory, with a crossover temperature, T-c, some 50% greater than the caloric glass transition temperature. The longer time alpha-relaxation reveals a failure of the Stokes-Einstein relation. (C) 1999 Elsevier Science B.V. All rights reserved. C1 NIST, Gaithersburg, MD 20899 USA. Univ Maryland, College Pk, MD 20742 USA. Tech Univ Munich, Dept Phys, D-85747 Garching, Germany. RP Meyer, A (reprint author), NIST, Gaithersburg, MD 20899 USA. RI Wuttke, Joachim/C-1142-2008; Meyer, Andreas/F-6260-2013; Petry, Winfried/K-4998-2016 OI Petry, Winfried/0000-0001-5208-7070 NR 16 TC 7 Z9 7 U1 0 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-3093 J9 J NON-CRYST SOLIDS JI J. Non-Cryst. Solids PD AUG PY 1999 VL 250 BP 116 EP 119 DI 10.1016/S0022-3093(99)00155-6 PN 1 PG 4 WC Materials Science, Ceramics; Materials Science, Multidisciplinary SC Materials Science GA 231ED UT WOS:000082294400023 ER PT J AU Wang, WM McPhaden, MJ AF Wang, WM McPhaden, MJ TI The surface-layer heat balance in the equatorial Pacific Ocean. Part I: Mean seasonal cycle SO JOURNAL OF PHYSICAL OCEANOGRAPHY LA English DT Article ID TROPICAL PACIFIC; MIXED-LAYER; EL-NINO; MODEL SIMULATION; ENSO PREDICTION; REDUCED GRAVITY; TEMPERATURE; VARIABILITY; ATMOSPHERE; BUDGET AB The surface-layer heat balance in the equatorial Pacific is examined in order to determine the processes responsible for the mean seasonal cycle of sea surface temperature (SST). Principal datasets include multiyear time series of surface winds, upper-ocean temperature, and velocity obtained from Tropical Atmosphere Ocean (TAO) buoy array at four locations along the equator in the western (165 degrees E), central (170 degrees W), and eastern (140 degrees and 110 degrees W) Pacific. A blended satellite-in situ SST product and climatological surface heat fluxes based on the Comprehensive Ocean-Atmosphere Data Set are also used. Changes in heat storage, horizontal heat advection. and hear fluxes at the surface are estimated directly from data; vertical fluxes of heat out of the base of the mixed layer are calculated as a residual. Results indicate that, of the terms that can be directly estimated, the net surface heat flux is generally the largest term in heat balance. Zonal heat advection is important at all locations and is generally a cooling term except in the eastern Pacific where the springtime reversal of the South Equatorial Current leads to warming. Meridional heat advection is largest in the eastern Pacific where it is dominated by seasonally varying tropical instability waves, which tend to warm the equator. The inferred vertical heat fluxes out the base of the mixed layer are comparable in magnitude to the surface fluxes, except in the western Pacific where they are close to zero. From these inferred vertical fluxes, the authors estimate the mean seasonal cycles in vertical eddy diffusivities and entrainment velocities, which, in the eastern Pacific, mimic the mean seasonal cycle of the surface winds, implications for modeling and predicting SST are addressed. C1 NOAA, Pacific Marine Environm Lab, Seattle, WA 98115 USA. Univ Washington, Sch Oceanog, Seattle, WA 98195 USA. RP Wang, WM (reprint author), NOAA, Pacific Marine Environm Lab, 7600 Sand Point Way Ne, Seattle, WA 98115 USA. RI McPhaden, Michael/D-9799-2016 NR 77 TC 106 Z9 107 U1 2 U2 16 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 1999 VL 29 IS 8 BP 1812 EP 1831 DI 10.1175/1520-0485(1999)029<1812:TSLHBI>2.0.CO;2 PN 1 PG 20 WC Oceanography SC Oceanography GA 236PG UT WOS:000082607300012 ER PT J AU Kessler, WS AF Kessler, WS TI Interannual variability of the subsurface high salinity tongue south of the equator at 165 degrees E SO JOURNAL OF PHYSICAL OCEANOGRAPHY LA English DT Article ID TROPICAL PACIFIC-OCEAN; SEA-SURFACE TEMPERATURE; NORTH PACIFIC; MEAN WATER; EL-NINO; CLIMATE; PRECIPITATION; UNDERCURRENT; CIRCULATION; TRANSPORTS AB A 14-yr time series of salinity at thermocline level was constructed from repeated meridional CTD sections (averaging about 110 days apart) spanning the equator along 165 degrees E during 1984-97. A tongue of high salinity water extends along the isopycnal sigma(1) = 24.5 from its surface outcrop in the southeast Pacific to 175-m depth near 5 degrees-10 degrees S along the section at 165 degrees E. In the west, the tongue moves vertically with the thermocline, mostly as part of the ENSO cycle, while salinity in the tongue varied interannually over a range of 0.4 psu. Most of this variability was due to zonal advection along the isopycnal tongue, with similar changes observed at other longitudes in the west and central Pacific. Part of the interannual salinity signal can be attributed to changes in the near-zonal flow of the South Equatorial Current associated with El Nino, but a general 0.3 psu rise occurring during the 1990s (probably starting even earlier) was not apparently consistent with this explanation. An attempt was made to trace the source of these changes to surface fluxes at the outcrop, where the variation of evaporation and precipitation suggested salinity anomalies of the same magnitude as the subsurface changes. However, the implied surface salinity changes were of the wrong sign to explain the subsequent downstream subsurface variability, and therefore present observations do not demonstrate any influence of subduction of surface properties on salinity in the southern high salinity tongue. C1 NOAA, Pacific Marine Environm Lab, Seattle, WA 98115 USA. RP Kessler, WS (reprint author), NOAA, Pacific Marine Environm Lab, 7600 Sand Point Way Ne, Seattle, WA 98115 USA. NR 35 TC 58 Z9 58 U1 0 U2 4 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-3670 J9 J PHYS OCEANOGR JI J. Phys. Oceanogr. PD AUG PY 1999 VL 29 IS 8 BP 2038 EP 2049 DI 10.1175/1520-0485(1999)029<2038:IVOTSH>2.0.CO;2 PN 2 PG 12 WC Oceanography SC Oceanography GA 236PJ UT WOS:000082607500009 ER PT J AU Mellor, G AF Mellor, G TI Comments on "On the utility and disutility of JEBAR" SO JOURNAL OF PHYSICAL OCEANOGRAPHY LA English DT Editorial Material ID NORTH-ATLANTIC; GULF-STREAM; WIND STRESS; CIRCULATION; OCEAN; RECIRCULATION; TRANSPORT C1 Princeton Univ, Program Atmospher Ocean Sci, Princeton, NJ 08544 USA. RP Mellor, G (reprint author), Princeton Univ, Program Atmospher Ocean Sci, POB CN710,Sayre Hall, Princeton, NJ 08544 USA. NR 12 TC 9 Z9 10 U1 0 U2 2 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 1999 VL 29 IS 8 BP 2117 EP 2118 DI 10.1175/1520-0485(1999)029<2117:COOTUA>2.0.CO;2 PN 2 PG 2 WC Oceanography SC Oceanography GA 236PJ UT WOS:000082607500016 ER PT J AU Schreyer, A Majkrzak, CF Berk, NF Grull, H Han, CC AF Schreyer, A Majkrzak, CF Berk, NF Grull, H Han, CC TI Using polarized neutrons to determine the phase of reflection from thin film structures SO JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS LA English DT Article; Proceedings Paper CT 7th Institute-for-Solid-State-Physics Symposium on Frontiers in Neutron Scattering Research (ISSP7) CY NOV 24-27, 1998 CL TOKYO, JAPAN SP Inst Solid State Phys DE neutron scattering; reflectivity; thin films; polymers ID REFLECTOMETRY AB It is now known that the phase of neutron specular reflection from a flat film structure can be determined exactly using reference layers, even in the dynamical regime at small wavevector transfer where the Born approximation is not valid. By employing a single buried ferromagnetic layer and polarized beams, two complex reflection amplitudes for the unknown part of the film can be algebraically extracted, only one of which is physical. We describe here a means of identifying the physical branch for actual polymer film data which fits the true reflection amplitude and produces the film's scattering length density profile directly and unambiguously. (C) 1999 Published by Elsevier Science Ltd. All rights reserved. C1 Natl Inst Stand & Technol, Mat Sci & Engn Lab, Ctr Neutron Res, Gaithersburg, MD 20899 USA. Natl Inst Stand & Technol, Mat Sci & Engn Lab, Div Polymers, Gaithersburg, MD 20899 USA. RP Schreyer, A (reprint author), Ruhr Univ Bochum, D-44780 Bochum, Germany. NR 11 TC 19 Z9 19 U1 0 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0022-3697 J9 J PHYS CHEM SOLIDS JI J. Phys. Chem. Solids PD AUG-SEP PY 1999 VL 60 IS 8-9 BP 1045 EP 1051 DI 10.1016/S0022-3697(99)00045-1 PG 7 WC Chemistry, Multidisciplinary; Physics, Condensed Matter SC Chemistry; Physics GA 226AK UT WOS:000081998000009 ER PT J AU Wakimoto, S Yamada, K Ueki, S Shirane, G Lee, YS Kastner, MA Hirota, K Gehring, PM Endoh, Y Birgeneau, RJ AF Wakimoto, S Yamada, K Ueki, S Shirane, G Lee, YS Kastner, MA Hirota, K Gehring, PM Endoh, Y Birgeneau, RJ TI Neutron scattering study of elastic magnetic signals in superconducting La1.94Sr0.06CuO4 SO JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS LA English DT Article; Proceedings Paper CT 7th Institute-for-Solid-State-Physics Symposium on Frontiers in Neutron Scattering Research (ISSP7) CY NOV 24-27, 1998 CL TOKYO, JAPAN SP Inst Solid State Phys DE superconductors; crystal growth; neutron scattering; magnetic properties; superconductivity ID LA2-XSRXCUO4 AB Recent neutron-scattering experiments on La2-xSrxCuO4 single crystals by Wakimoto et al. (unpublished) have revealed that elastic magnetic peaks appear at low temperatures in both insulating (x = 0.02-0.05) and superconducting (x = 0.06) samples. We have carried out further investigations particularly on the elastic incommensurate peaks for x = 0.06, and found that the integrated intensity drastically changes across the low temperature insulator-superconductor boundary; the intensity of x = 0.06 is four times smaller than that of x = 0.05, whereas the intensity in the insulating region stays constant. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Tohoku Univ, Dept Phys, Sendai, Miyagi 9808578, Japan. Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. MIT, Dept Phys, Cambridge, MA 02139 USA. NIST, Ctr Neutron Res, Gaithersburg, MD 20899 USA. Univ Maryland, College Pk, MD 20742 USA. RP Hirota, K (reprint author), Tohoku Univ, Dept Phys, Sendai, Miyagi 9808578, Japan. RI Yamada, Kazuyoshi/C-2728-2009; OI Gehring, Peter/0000-0002-9236-2046 NR 7 TC 5 Z9 5 U1 1 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0022-3697 J9 J PHYS CHEM SOLIDS JI J. Phys. Chem. Solids PD AUG-SEP PY 1999 VL 60 IS 8-9 BP 1079 EP 1081 DI 10.1016/S0022-3697(99)00052-9 PG 3 WC Chemistry, Multidisciplinary; Physics, Condensed Matter SC Chemistry; Physics GA 226AK UT WOS:000081998000016 ER PT J AU Jeng, US Lin, TL Tsao, CS Lee, CH Wang, LY Chiang, LY Sung, LP Han, CC AF Jeng, US Lin, TL Tsao, CS Lee, CH Wang, LY Chiang, LY Sung, LP Han, CC TI SANS study on a fullerenol-based poly(urethane-ether) elastomer SO JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS LA English DT Article; Proceedings Paper CT 7th Institute-for-Solid-State-Physics Symposium on Frontiers in Neutron Scattering Research (ISSP7) CY NOV 24-27, 1998 CL TOKYO, JAPAN SP Inst Solid State Phys DE polymer; neutron scattering ID ANGLE NEUTRON-SCATTERING; POLYHYDROXYLATED C-60 AB The structure of a fullerenol hypercrosslinked poly(urethane-ether) elastomer has been characterized by small angle neutron scattering. The observed scattering profile indicates an isotropic dispersion of the crosslinking agents, fullerenols C-60(OH)(12), in the matrix of poly(urethane-ether) (PU). The mean spacing between the crosslinking sites, obtained from the correlation function is 150 Angstrom, which is related to the conformation of the PU arms in the network. The same elastomer has also been measured under an uniaxial stretch. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Natl Tsing Hua Univ, Dept Engn & Syst Sci, Hsinchu 300, Taiwan. Inst Nucl Energy Res, Div Nucl Fuel & Mat, Lungtan 325, Taiwan. Natl Taiwan Univ, Ctr Condensed Matter Sci, Taipei 106, Taiwan. Natl Inst Stand & Technol, Gaithersburg, MD USA. RP Lin, TL (reprint author), Natl Tsing Hua Univ, Dept Engn & Syst Sci, Hsinchu 300, Taiwan. OI Lee, Chih-Hao/0000-0002-3898-6421 NR 10 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 0022-3697 J9 J PHYS CHEM SOLIDS JI J. Phys. Chem. Solids PD AUG-SEP PY 1999 VL 60 IS 8-9 BP 1347 EP 1349 DI 10.1016/S0022-3697(99)00107-9 PG 3 WC Chemistry, Multidisciplinary; Physics, Condensed Matter SC Chemistry; Physics GA 226AK UT WOS:000081998000079 ER PT J AU Ikeda, T Miyazawa, K Izumi, F Huang, Q Santoro, A AF Ikeda, T Miyazawa, K Izumi, F Huang, Q Santoro, A TI Structural study of the aluminophosphate AlPO4-5 by neutron powder diffraction SO JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS LA English DT Article; Proceedings Paper CT 7th Institute-for-Solid-State-Physics Symposium on Frontiers in Neutron Scattering Research (ISSP7) CY NOV 24-27, 1998 CL TOKYO, JAPAN SP Inst Solid State Phys DE microporous materials; neutron scattering; crystal structure ID MICROWAVE AB The structures of an aluminophosphate AlPO4-5 produced by a microwave-heating method were determined by neutron powder diffraction, An as-prepared sample incorporating triethylamine as a template crystallized in hexagonal form with space group P6cc, Template molecules were oriented in a head-to-tail manner along the c-axis. On the contrary, a sample calcined to remove triethylamine was orthorhombic with space group Pnn2 or Pcc2, The framework of AlPO4-5 proved to change easily by removing the guest material from its one-dimensional cavity. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Univ Tsukuba, Inst Appl Phys, Tsukuba, Ibaraki 3058573, Japan. Natl Inst Adv Interdisciplinary Res, Tsukuba, Ibaraki 3058562, Japan. Natl Inst Res Inorgan Mat, Tsukuba, Ibaraki 3050044, Japan. Natl Inst Stand & Technol, Ctr Neutron Res, Gaithersburg, MD 20899 USA. RP Ikeda, T (reprint author), Univ Tsukuba, Inst Appl Phys, Tsukuba, Ibaraki 3058573, Japan. NR 10 TC 17 Z9 18 U1 2 U2 6 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0022-3697 J9 J PHYS CHEM SOLIDS JI J. Phys. Chem. Solids PD AUG-SEP PY 1999 VL 60 IS 8-9 BP 1531 EP 1535 DI 10.1016/S0022-3697(99)00166-3 PG 5 WC Chemistry, Multidisciplinary; Physics, Condensed Matter SC Chemistry; Physics GA 226AK UT WOS:000081998000122 ER PT J AU Butler, BD Hanley, HJM AF Butler, BD Hanley, HJM TI Aggregation in quenched systems interacting through a short-range attractive, long-range repulsive potential SO JOURNAL OF SOL-GEL SCIENCE AND TECHNOLOGY LA English DT Article DE computer simulation; gelation; quenched systems; repulsive potential; network formation ID LENNARD-JONES SYSTEM; FRACTAL AGGREGATION; CLUSTER AGGREGATION; SCATTERING; DYNAMICS; SIMULATIONS; GELATION; SILICA AB The morphology and structure factor of a 2D system of particles interacting through a Lennard-Jones potential, modified to include a long-range repulsive component, are described. Of particular interest are those systems quenched from a stabilized colloidal state to temperatures that, in the pure Lennard-Jones system, correspond to the solid-vapor coexistence region. We find that competition between the short-range attractive forces-which cause aggregation-and the long-range repulsion-which acts to keep the particles apart-encourages the formation of space-filling networks. A characteristic peak in the structure factor is observed which moves toward lower wavevectors as the simulation evolves. However, unlike the pure Lennard-Jones system, which when given enough time will completely phase separate, this peak stops moving once a network has formed. The similarities between our simulations and gel formation are discussed. C1 Natl Inst Stand & Technol, Phys & Chem Propert Din, Boulder, CO 80303 USA. RP Butler, BD (reprint author), Natl Inst Stand & Technol, Phys & Chem Propert Din, 325 Broadway, Boulder, CO 80303 USA. NR 19 TC 4 Z9 4 U1 0 U2 1 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0928-0707 J9 J SOL-GEL SCI TECHN JI J. Sol-Gel Sci. Technol. PD AUG PY 1999 VL 15 IS 2 BP 161 EP 166 DI 10.1023/A:1008791522737 PG 6 WC Materials Science, Ceramics SC Materials Science GA 216YL UT WOS:000081472000007 ER PT J AU Rijssenbeek, JT Huang, Q Erwin, RW Zandbergen, HW Cava, RJ AF Rijssenbeek, JT Huang, Q Erwin, RW Zandbergen, HW Cava, RJ TI The crystal structure of Ba3CuRu2O9 and comparison to Ba3MRu2O9 (M = In, Co, Ni, and Fe) SO JOURNAL OF SOLID STATE CHEMISTRY LA English DT Article ID PEROVSKITES AB The crystal structure of Ba3CuRu2O9, determined by powder neutron diffraction, is reported for temperatures of 18-295 K. Structural refinements by powder neutron diffraction for the previously reported compounds Ba3MRu2O9 for M = Fe, Co, Ni, and In are also reported. All structures consist of pairs of face-shared RuO6 octahedra interconnected by corner-sharing MO6 octahedra. For Ba3Cu Ru2O9, Jahn-Teller distortion of the CuO6 octahedra leads to an orthorhombic symmetry structure of space group Cmcm with a = 5.6723(1), b = 10.1722(3), and c = 14.1575(3) Angstrom at 295 K. For Ba3FeRu2O9, site occupancy disorder is found. Magnetic ordering is observed below 100, 105, and 110 K for M = Cu, Ni, and Co, respectively. The magnetic structures at low temperatures for M = Co and Ni are described and compared to previous reports. (C) 1999 Academic Press. C1 Princeton Univ, Dept Chem, Princeton, NJ 08540 USA. Princeton Univ, Inst Mat, Princeton, NJ 08540 USA. NIST, Ctr Neutron Res, Gaithersburg, MD 20899 USA. Univ Maryland, Dept Mat & Nucl Engn, College Pk, MD 20742 USA. Delft Univ Technol, Mat Sci Lab, Natl Inst HREM, NL-2628 AL Delft, Netherlands. RP Cava, RJ (reprint author), Princeton Univ, Dept Chem, Princeton, NJ 08540 USA. NR 12 TC 36 Z9 36 U1 6 U2 10 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0022-4596 J9 J SOLID STATE CHEM JI J. Solid State Chem. PD AUG PY 1999 VL 146 IS 1 BP 65 EP 72 DI 10.1006/jssc.1999.8309 PG 8 WC Chemistry, Inorganic & Nuclear; Chemistry, Physical SC Chemistry GA 222CR UT WOS:000081766300010 ER PT J AU Yamaura, K Huang, Q Cava, RJ AF Yamaura, K Huang, Q Cava, RJ TI Synthesis, crystal structure, electrical, and magnetic properties of the new layered cobalt oxides (Sr, Ca, Ln)(3)Co2O6 +/-delta (Ln = Sm, Eu, Gd, Tb, Dy, Ho, and Y) SO JOURNAL OF SOLID STATE CHEMISTRY LA English DT Article DE Sr-2(Ln,Ca)Co2O6; La2-xSrxCaCu2O6; layered structure; spin glass; Kohlrausch law ID SUPERCONDUCTIVITY; LACOO3 AB New layered Co oxides of nominal formula Sr-2(Ln(0.8)Ca(0.2)) Co2O6 (Ln = Sm, Eu, Gd, Tb, Dy, Ho, and Y) are reported. Single-phase polycrystalline samples were obtained at compositions Sr2Y1-xCaxCo22.5+O6-delta (0.2 less than or equal to x less than or equal to 0.5; 0 less than or equal to delta less than or equal to 0.24), Sr2Y1-xCaxCo23.4+O6+delta' (0.2 less than or equal to x less than or equal to 0.5; 0.62 less than or equal to delta' less than or equal to 0.79), and Sr2Dy0.8Ca0.2Co2O6.09. Powder X-ray and neutron diffraction, thermogravimetric analysis, magnetic susceptibility, and ac resistivity measurements were used to characterize the samples. The tetragonal unit cell for Sr2Y0.8Ca0.2Co2O6.00 (I4/mmm; a = 3.82765(6) Angstrom, and c = 19.5795(3) Angstrom) is comparable to that of the double layer superconducting copper oxide La2-xSrxCaCu2 O-6. A long-range antiferromagnetic (AF) ordered state below about 300 K is found for Sr2Y1-xCaxCo22.5+O6-delta, and a magnetically glassy state below about 40 K for the oxidized AF phases. All materials are electrically insulating, (C) 1999 Academic Press. C1 Princeton Univ, Dept Chem, Princeton, NJ 08540 USA. Princeton Univ, Princeton Mat Inst, Princeton, NJ 08540 USA. Natl Inst Stand & Technol, Ctr Neutron Res, Gaithersburg, MD 20899 USA. Univ Maryland, Dept Mat & Nucl Engn, College Pk, MD 20742 USA. RP Yamaura, K (reprint author), Princeton Univ, Dept Chem, Princeton, NJ 08540 USA. NR 16 TC 26 Z9 27 U1 0 U2 2 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0022-4596 J9 J SOLID STATE CHEM JI J. Solid State Chem. PD AUG PY 1999 VL 146 IS 1 BP 277 EP 286 DI 10.1006/jssc.1999.8375 PG 10 WC Chemistry, Inorganic & Nuclear; Chemistry, Physical SC Chemistry GA 222CR UT WOS:000081766300041 ER PT J AU Ogi, H Ledbetter, H Kim, S Hirao, M AF Ogi, H Ledbetter, H Kim, S Hirao, M TI Contactless mode-selective resonance ultrasound spectroscopy: Electromagnetic acoustic resonance SO JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA LA English DT Article ID ELASTIC-CONSTANTS; ATTENUATION; SOLIDS; DEPENDENCE; MODULI; FILM AB A noncontacting resonant-ultrasound-spectroscopy (RUS) method for measuring elastic constants and internal friction of conducting materials is described, and applied to monocrystalline copper. This method is called electromagnetic acoustic resonance (EMAR). Contactless acoustic coupling is achieved by energy transduction between the electromagnetic field and the ultrasonic vibrations. A solenoidal coil and static magnetic field induce Lorentz forces on specimen surfaces without using a coupling agent. By changing the field direction, a particular set of vibration modes can be selectively excited and detected, an advantage in identifying the vibration modes of the observed resonance peaks. Contactless coupling allows the measure of intrinsic internal friction free from energy loss associated with contact coupling. The elastic constants and internal friction measured by EMAR are compared with those by the usual RUS method for a rectangular-parallelepiped copper monocrystal. Both methods yielded the same elastic constants despite fewer resonant peaks in the EMAR case. The two methods gave essentially the same shear-mode internal friction, but the RUS method gave higher volume-mode internal friction. (C) 1999 Acoustical Society of America. [S0001-4966(99)05208-X]. C1 Osaka Univ, Grad Sch Engn Sci, Osaka 5608531, Japan. Natl Inst Stand & Technol, Mat Sci & Engn Lab, Boulder, CO 80303 USA. RP Ogi, H (reprint author), Osaka Univ, Grad Sch Engn Sci, Machikaneyama 1-3, Osaka 5608531, Japan. NR 29 TC 74 Z9 76 U1 1 U2 14 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0001-4966 J9 J ACOUST SOC AM JI J. Acoust. Soc. Am. PD AUG PY 1999 VL 106 IS 2 BP 660 EP 665 DI 10.1121/1.427607 PG 6 WC Acoustics; Audiology & Speech-Language Pathology SC Acoustics; Audiology & Speech-Language Pathology GA 225YN UT WOS:000081993700013 ER PT J AU Kuhns, H Green, M Pitchford, M Vasconcelos, L White, W Mirabella, V AF Kuhns, H Green, M Pitchford, M Vasconcelos, L White, W Mirabella, V TI Attribution of particulate sulfur in the Grand Canyon to specific point sources using tracer-aerosol gradient interpretive technique (TAGIT) SO JOURNAL OF THE AIR & WASTE MANAGEMENT ASSOCIATION LA English DT Article ID PROJECT; MOHAVE; MODEL AB Since aerosol particulate sulfur is generally a secondary airborne pollutant, most source attribution techniques require many assumptions about the transport and chemistry of sulfur dioxide (SO2) emissions. Uncertainties in our understanding of these processes impair our ability to generate reliable attribution information that is necessary for designing cost-effective pollution control policies. A new attribution technique using artificial tracer is presented in hopes of reducing the uncertainty of secondary aerosol source attribution. The Tracer-Aerosol Gradient interpretive Technique (TAGIT) uses tracer data from a monitoring network to distinguish sites impacted by a source tagged with tracer from nonimpacted sites. Sites determined not to be influenced by the plume are considered to represent background particulate sulfur concentrations. The particulate sulfur attributable to the source at sites within the plume is calculated as the difference between observed and background particulate sulfur TAGIT is applied to measurements made in the vicinity of the east and west ends of the Grand Canyon in order to attribute particulate sulfur to the sources within the Eastern Colorado River Valley (ECRV) and the Mohave Power Project (MPP), respectively. TAGIT results indicate that during the winter intensive field sampling experiment (January 15-February 13, 1992), an average of 59 +/- 12% of the particulate sulfur at Marble Canyon, AZ, was attributable to ECRV sources. Similarly during the summer field sampling experiment (July 13-August 30, 1992), MPP is estimated to have contributed an average of 7 +/- 3% of the particulate sulfur at Meadview, AZ. Uncertainties associated with the assumptions of TAGIT are discussed and quantified. The attribution results suggest that SO2-to-sulfate conversion rates are highly variable from day to day in this region. C1 Desert Res Inst, Las Vegas, NV 89119 USA. NOAA, Air Resources Lab, Special Operat & Res Div, Las Vegas, NV USA. Washington Univ, St Louis, MO USA. So Calif Edison, Rosemead, CA USA. RP Kuhns, H (reprint author), Desert Res Inst, 755 E Flamingo Rd, Las Vegas, NV 89119 USA. RI Kuhns, Hampden/C-3563-2008; OI White, Warren H/0000-0001-7323-7867 NR 18 TC 9 Z9 9 U1 0 U2 0 PU AIR & WASTE MANAGEMENT ASSOC PI PITTSBURGH PA ONE GATEWAY CENTER, THIRD FL, PITTSBURGH, PA 15222 USA SN 1047-3289 J9 J AIR WASTE MANAGE JI J. Air Waste Manage. Assoc. PD AUG PY 1999 VL 49 IS 8 BP 906 EP 915 PG 10 WC Engineering, Environmental; Environmental Sciences; Meteorology & Atmospheric Sciences SC Engineering; Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA 230WD UT WOS:000082273900003 PM 28060628 ER PT J AU Quinn, JB AF Quinn, JB TI Extrapolation of fracture mirror and crack-branch sizes to large dimensions in biaxial strength tests of class SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Article ID GLASS; MECHANICS; DESIGN AB Annealed glass disks were fractured in biaxial tension under a variety of conditions; crack lengths prior to branching and the sizes of the mirror and mist regions were measured. The experimental results indicated the expected correlation between fracture stress and these fracture features, except for an extrapolation to a consistent, clearly defined y-ntercept. Neither environment, surface preparation, nor the rate of applied stress was a factor in the fracture stress versus branch, mirror, or mist size relationships. C1 Univ Maryland, Dept Mat Engn, College Pk, MD 20742 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Quinn, JB (reprint author), Univ Maryland, Dept Mat Engn, College Pk, MD 20742 USA. NR 43 TC 12 Z9 12 U1 0 U2 1 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, PO BOX 6136, WESTERVILLE, OH 43081-6136 USA SN 0002-7820 J9 J AM CERAM SOC JI J. Am. Ceram. Soc. PD AUG PY 1999 VL 82 IS 8 BP 2126 EP 2132 PG 7 WC Materials Science, Ceramics SC Materials Science GA 291WZ UT WOS:000085763500027 ER PT J AU Munro, RG Freiman, SW AF Munro, RG Freiman, SW TI Correlation of fracture toughness and strength SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Article ID MECHANICAL-PROPERTIES; TEMPERATURE FRACTURE; GRAIN-SIZE; MULLITE; CERAMICS; DEPENDENCE; ZIRCONIA; AIN; TZP AB An extensive collection of data on the fracture toughness (K-Ic) and strength (sigma(f)) of brittle materials has been used to examine the relationship between the mean measured values of K-Ic and sigma(f). Within this collection of data, it has been observed empirically that K-Ic frequently is linearly related to sigma(f) when values are compared under conditions of either constant grain size (g) or constant density (rho). Assuming that the most-significant material parameters are g and rho, the general fracture-mechanics relationship among K-Ic, sigma(f), and the critical flan size (c(0)) has been used to derive a general expression for (partial derivative K-Ic/partial derivative sigma(f))(x) in which the subscript x indicates a condition of constant grain size (x = g) or constant density (x = rho). In general, (partial derivative K-Ic/partial derivative sigma(f))(g) is not the same as (partial derivative K-Ic/partial derivative sigma(f))(rho). Imposing the empiricalcondition (partial derivative K-Ic/partial derivative sigma(f))(x) = lambda(x), where lambda(x) is a constant, a relationship between sigma(f) and flaw size has been derived. For the observed conditions, the analysis indicates that the square root of the flaw size should vary as the reciprocal of the observed fracture strength. C1 Natl Inst Stand & Technol, Div Ceram, Gaithersburg, MD 20899 USA. RP Munro, RG (reprint author), Natl Inst Stand & Technol, Div Ceram, Gaithersburg, MD 20899 USA. NR 27 TC 7 Z9 8 U1 1 U2 7 PU AMER CERAMIC SOC PI WESTERVILLE PA 735 CERAMIC PLACE, PO BOX 6136, WESTERVILLE, OH 43081-6136 USA SN 0002-7820 J9 J AM CERAM SOC JI J. Am. Ceram. Soc. PD AUG PY 1999 VL 82 IS 8 BP 2246 EP 2248 PG 3 WC Materials Science, Ceramics SC Materials Science GA 291WZ UT WOS:000085763500044 ER PT J AU Stein, SE AF Stein, SE TI An integrated method for spectrum extraction and compound identification from gas chromatography/mass spectrometry data SO JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY LA English DT Article ID MASS-SPECTRA AB A method is presented for extracting individual component spectra from gas chromatography/mass spectrometry (GC/MS) data files and then using these spectra to identify target compounds by matching spectra in a reference Library. It extends a published "model peak" approach which uses selected ion chromatograms as models for component shape. On the basis of this shape, individual mass spectral peak abundance profiles are extracted to produce a "purified" spectrum. In the present work, ion-counting noise is explicitly treated and a number of characteristic features of GC/MS data are taken into account. This allows spectrum extraction to be reliably performed down to very low signal levels and for overlapping components. A spectrum match factor for compound identification is developed that incorporates a number of new corrections, some of which employ information derived from chromatographic behavior. Test results suggest that the ability of this system to identify compounds is comparable to that of conventional analysis. C1 NIST, Mass Spectrometry Data Ctr, Phys & Chem Properties Div, Gaithersburg, MD 29899 USA. RP Stein, SE (reprint author), NIST, Mass Spectrometry Data Ctr, Phys & Chem Properties Div, Stop 8380,100 Bur Dr, Gaithersburg, MD 29899 USA. NR 13 TC 391 Z9 413 U1 5 U2 55 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 USA SN 1044-0305 J9 J AM SOC MASS SPECTR JI J. Am. Soc. Mass Spectrom. PD AUG PY 1999 VL 10 IS 8 BP 770 EP 781 DI 10.1016/S1044-0305(99)00047-1 PG 12 WC Chemistry, Analytical; Chemistry, Physical; Spectroscopy SC Chemistry; Spectroscopy GA 221JP UT WOS:000081724200011 ER PT J AU Purser, RJ AF Purser, RJ TI Legendre-transformable semigeostrophic theories SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID SEMI-GEOSTROPHIC EQUATIONS; HAMILTON PRINCIPLE; FLOW; VORTICES; MODELS; FRONTOGENESIS; FORMULATION; CONVECTION; DYNAMICS; FIELDS AB For semigeostrophic (SG) theories derived from the Hamiltonian principles suggested by Salmon it is known that a duality exists between the physical coordinates and geopotential, on the one hand, and isentropic geostrophic momentum coordinates and geostrophic Bernoulli function, on the other hand. The duality is characterized geometrically by a contact structure. This enables the idealized balanced dynamics to be represented by horizontal geostrophic motion in the dual coordinates while the mapping back to physical space is determined uniquely by requiring each instantaneous state to be the one of minimum energy with respect to volume-conserving rearrangements within the physical domain. It is found that the generic contact structure permits the emergence of topological anomalies during the evolution of discontinuous flows. For both theoretical and computational reasons it is desirable to seek special forms of SG dynamics in which the structure of the contact geometry prohibits such anomalies. It is proven in this paper that this desideratum is equivalent to the existence of a mapping of geographical position to a Euclidean domain, combined with some position-dependent additive modification of the geopotential, which results in the SG theory being manifestly Legendre transformable from this alternative representation to its associated dual variables. Legendre-transformable representations for standard Boussinesq f-plane SG theory and for the axisymmetric gradient-balance version used to study the Eliassen vortex are already known and exploited in finite clement algorithms. Here, two other potentially useful classes of SG theory discussed in a recent paper by the author are reexamined: (i) the nonaxisymmetric f-plane vortex and (ii) hemispheric (variable f) SG dynamics. The authors find that the imposition of the natural dynamical and geometrical symmetry requirements together with the requirement of Legendre transformability makes the choice of the S-plane vortex theory unique. Moreover, with modifications to accommodate sphericity, this special vortex theory supplies what appears to be the most symmetrical and consistent formulation of variable-f SG theory on the hemisphere. The Legendre-transformable representations of these theories appear superficially to violate the original symmetry of rotation about the vortex axis. Bur, remarkably, this symmetry is preserved provided one interprets the metric of the new representation to be a pseudo-Euclidean Minkowski metric. Rotation invariance of the dynamical formulation in physical space is then perceived as a formal Lorentz invariance in its Legendre-transformable representation. C1 Gen Sci Corp, Laurel, MD USA. Isaac Newton Inst, Program Atmosphere & Ocean Dynam, Cambridge, England. RP Purser, RJ (reprint author), Natl Ctr Environm Predict, W-NP2 WWB,Room 207, Washington, DC 20233 USA. NR 39 TC 5 Z9 5 U1 0 U2 0 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 AUG 1 PY 1999 VL 56 IS 15 BP 2522 EP 2535 DI 10.1175/1520-0469(1999)056<2522:LTST>2.0.CO;2 PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 227ME UT WOS:000082083500004 ER PT J AU Charron, M Brunet, G AF Charron, M Brunet, G TI Gravity wave diagnosis using empirical normal modes SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID GENERAL-CIRCULATION MODEL; GEOSTROPHIC ADJUSTMENT; JET-STREAM; INSTABILITY; EXCITATION; STRATOSPHERE; FLOWS AB The theory of empirical normal modes (ENMs) is adapted to diagnose gravity waves generated by a relatively high-resolution numerical model solving the primitive equations. The ENM approach is based on the principal component analysis (which consists of finding the most efficient basis explaining the variance of a time series), except that it takes advantage of wave-activity conservation laws. In the present work, the small-amplitude version of the pseudoenergy is used to extract from data quasi-monochromatic three-dimensional empirical modes that describe atmospheric wave activity. The spatial distributions of these quasi-monochromatic modes are identical to the normal modes of the linearized primitive equations when the underlying dynamics can be described with a stochastic linear and forced model, thus establishing a bridge between statistics and dynamics. This diagnostic method is used to study inertia-gravity wave generation, propagation, transience, and breaking over the Rockies, the North Pacific, and Central America in the troposphere-stratosphere-mesosphere Geophysical Fluid Dynamics Laboratory SKYHI general circulation model at a resolution of 1 degrees of latitude by 1.2 degrees of longitude. Besides the action of mountains in exciting orographic waves, inertia-gravity wave activity has been found to be generated at the jet stream level as a possible consequence of a sustained nonlinear and ageostrophic flow. In the tropical region of the model (Central America), the inertia-gravity wave source mechanism produced mainly waves with a westward vertical tilt. A significant proportion of these inertia-gravity waves was able to reach the model mesosphere without much dissipation and absorption. C1 NOAA, Geophys Fluid Dynam Lab, Princeton, NJ USA. Atmospher Environm Serv, Dorval, PQ H9P 1J3, Canada. McGill Univ, Dept Atmospher & Ocean Sci, Montreal, PQ, Canada. RP Charron, M (reprint author), Atmospher Environm Serv, 2121 Route Transcanadienne, Dorval, PQ H9P 1J3, Canada. NR 35 TC 9 Z9 10 U1 0 U2 0 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 AUG 1 PY 1999 VL 56 IS 15 BP 2706 EP 2727 DI 10.1175/1520-0469(1999)056<2706:GWDUEN>2.0.CO;2 PG 22 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 227ME UT WOS:000082083500015 ER PT J AU Richter, LJ Jordan, CE Cavanagh, RR Bryant, GW Liu, AS Stranick, SJ Keating, CD Natan, MJ AF Richter, LJ Jordan, CE Cavanagh, RR Bryant, GW Liu, AS Stranick, SJ Keating, CD Natan, MJ TI Influence of secondary tip shape on illumination-mode near-field scanning optical microscopy images SO JOURNAL OF THE OPTICAL SOCIETY OF AMERICA A-OPTICS IMAGE SCIENCE AND VISION LA English DT Article ID RESOLUTION; SCATTERING; ARTIFACTS; SURFACES AB We report illumination-mode near-field optical microscopy images of individual 80-115-nm-diameter Au particles recorded with metal-coated fiber probes. It is found that the images are strongly influenced by the metal-coating thickness. This dependence is consistent with theoretical models, which are in good agreement with the experimental images. Probes with thick coatings (similar to lambda/2) produce images consisting of three extrema, owing to a resonancelike polarization of the probe end. Probes with thinner coatings generally produce simpler images. However, in some cases the images contain wavelike structures that are due to interference between direct radiation from the tip and propagating tip fields scattered by the particles. (C) 1999 Optical society of America [S0740-3232(99)01208-9]. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Penn State Univ, Dept Chem, University Pk, PA 16802 USA. RP Richter, LJ (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RI Richter, Lee/N-7730-2016; OI Richter, Lee/0000-0002-9433-3724; Keating, Christine/0000-0001-6039-1961 NR 24 TC 11 Z9 11 U1 0 U2 1 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 1999 VL 16 IS 8 BP 1936 EP 1946 DI 10.1364/JOSAA.16.001936 PG 11 WC Optics SC Optics GA 220MA UT WOS:000081668700006 ER PT J AU Hassett, RP Boehlert, GW AF Hassett, RP Boehlert, GW TI Spatial and temporal distributions of copepods to leeward and windward of Oahu, Hawaiian Archipelago SO MARINE BIOLOGY LA English DT Article ID ZOOPLANKTON FEEDING ECOLOGY; CONTINENTAL-SHELF WATERS; TROPICAL PACIFIC; UNDINULA-VULGARIS; PHYTOPLANKTON GROWTH; DEPTH DISTRIBUTION; OCEANIC COPEPODS; FECAL PELLETS; ISLAND; PATTERNS AB The spatial and temporal distributions of two island-associated copepod species, Undinula vulgaris Dana and Labidocera madurae Scott, were compared to the distributions of two open ocean species, Cosmocalanus darwinii Lubbock and Scolecithrix danae Lubbock, along 28-km windward and leeward transects off the island of Oahu, Hawaii. Samples were taken in September and December 1985 and April and June 1986. A warm, low salinity pool on the leeward side was a prominent feature during all transects except December. The abundances of the two oceanic species did not change significantly between leeward and windward stations, with distance from shore, or between September 1985 and April 1986 samples. As expected, very high abundances of U. vulgaris occurred at some nearshore stations, up to 3 g dry wt m(-2) for adults alone. Calculations of respiratory loss at these densities (0.7 g C m(-2) d(-1)) suggest a high local productivity would be required to meet these demands. L. madurae, a surface-dwelling species normally restricted to within 1 km of shore, was an effective indicator species of nearshore water movement. It was more common in offshore samples on the leeward transects, rarely being found offshore on the windward side, consistent with prevailing currents and the presence of the leeward warm, low salinity pool. The occurrence of a strong mixing event in April 1986 resulted in L. madurae being distributed throughout the upper 100 m of the water column. The presence of oceanic species close to shore on the windward side also coincided with this wind-driven event. The primary environmental influence on vertical distributions was daytime cloud cover, with U. vulgaris tending to be found shallower on cloudy days. Of the two oceanic species, S. danae exhibited the most pronounced vertical migration,however, vertical distributions were not significantly correlated with environmental factors for either species. The abundant nearshore U. vulgaris population cannot be explained by differences in vertical distribution between it and the two oceanic species that might allow a physical mechanism to concentrate U. vulgaris. A high population growth rate is likely necessary to explain U. vulgaris' dominance. C1 Ohio Univ, Dept Biol Sci, Athens, OH 45701 USA. NMFS SW Fisheries Sci Ctr, Pacific Fisheries Environm Grp, Pacific Grove, CA 93950 USA. RP Hassett, RP (reprint author), Ohio Univ, Dept Biol Sci, Athens, OH 45701 USA. NR 48 TC 16 Z9 17 U1 0 U2 6 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0025-3162 J9 MAR BIOL JI Mar. Biol. PD AUG PY 1999 VL 134 IS 3 BP 571 EP 584 DI 10.1007/s002270050572 PG 14 WC Marine & Freshwater Biology SC Marine & Freshwater Biology GA 231FR UT WOS:000082297900017 ER PT J AU Lee, BS Bullister, JL Whitney, FA AF Lee, BS Bullister, JL Whitney, FA TI Chlorofluorocarbon CFC-11 and carbon tetrachloride removal in Saanich Inlet, an intermittently anoxic basin SO MARINE CHEMISTRY LA English DT Article DE chlorofluorocarbons; carbon tetrachloride; anoxic; Saanich Inlet; dehalogenation; hydrogen sulfide ID TRANSIENT TRACER; WEDDELL SEA; SEAWATER; DEEP; CHLOROFLUOROMETHANES; WATERS; OCEAN; SOILS; TRANSFORMATIONS; DISTRIBUTIONS AB Vertical distributions of the anthropogenic halocarbons CCl2F2 (CFC-12), CCl3F (CFC-11), and CCl4 (carbon tetrachloride) measured in Saanich Inlet, B.C,, Canada are used to estimate the renewal rates of bottom water, and to study the non-conservative behavior of these compounds in marine waters. Dissolved CFC-11 and CCl4 were strongly depleted in the deep anoxic hydrogen sulphide-bearing water, with CFC-11 concentrations <30% of saturation levels, and CCl4 concentrations near blank (< 1% of saturation) levels. In contrast, CFC-12 was near saturation throughout the water column. A short(similar to 10 day) incubation experiment using anoxic hydrogen sulphide-bearing water from Saanich Inlet showed rapid removal of CCl4 in non-poisoned samples, The removal was more rapid at 25 degrees C than at 0 degrees C or 40 degrees C, supporting the hypothesis that the removal is biologically mediated. Removal rates of CCl4 in poisoned samples, and removal rates of CFC-11 and CFC-12 in both poisoned and non-poisoned samples were undetectable within the 10 day incubation period. Longer incubation experiments using anoxic hydrogen sulphide-bearing water indicated that the decay rate of CFC-12 in both poisoned and non-poisoned samples was not detectable within similar to 2.5 years at 8 degrees C and similar to 4 months at 25 degrees C, while CFC-11 in non-poisoned samples was reactive with in situ first-order removal coefficients of similar to 0.5 yr(-1) (8 degrees C) and similar to 1.2 yr(-1) (25 degrees C), Results from these incubation experiments and measurements in Saanich Inlet support previous studies and indicate that CFC-12 behaves as a conservative tracer even in strongly anoxic hydrogen sulphide-bearing waters. In oxygenated waters, the removal of CFC-11 and CFC-12 was undetectable within incubation periods of - 2.5 years and - 4 months at temperatures 8 degrees C and 25 degrees C, respectively. In contrast, CCl4 was reactive in oxygenated waters with a removal rate constant of similar to 0.69 yr(-1). (C) 1999 Elsevier Science B.V. All rights reserved. C1 NOAA, Pacific Marine Environm Lab, Seattle, WA 98115 USA. Natl Sun Yat Sen Univ, Coll Marine Sci, Natl Ctr Ocean Res, Kaohsiung 804, Taiwan. Inst Ocean Sci, Dept Fisheries & Oceans, Sidney, BC V8L 4B2, Canada. RP Bullister, JL (reprint author), NOAA, Pacific Marine Environm Lab, 7600 Sand Point Way Ne, Seattle, WA 98115 USA. NR 37 TC 17 Z9 18 U1 1 U2 7 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0304-4203 J9 MAR CHEM JI Mar. Chem. PD AUG PY 1999 VL 66 IS 3-4 BP 171 EP 185 DI 10.1016/S0304-4203(99)00039-0 PG 15 WC Chemistry, Multidisciplinary; Oceanography SC Chemistry; Oceanography GA 229GN UT WOS:000082185300004 ER PT J AU Valette-Silver, N Hameedi, MJ Efurd, DW Robertson, A AF Valette-Silver, N Hameedi, MJ Efurd, DW Robertson, A TI Status of the contamination in sediments and biota from the western Beaufort Sea (Alaska) SO MARINE POLLUTION BULLETIN LA English DT Review ID POLYCYCLIC AROMATIC-HYDROCARBONS; SPILL EXPERIMENTAL SITES; BAFFIN ISLAND; UNITED-STATES; TRACE-METALS; CHEMICAL CONCENTRATIONS; CONTINENTAL-SHELF; STRATHCONA SOUND; ARCTIC COD; ESTUARINE AB Surficial sediments in the western Beaufort Sea contained generally high concentrations of arsenic (up to 58 ppm as corrected for grain size), very low amounts of organochlorine compounds and concentrations of total polycyclic aromatic hydrocarbons (PAHs) ranging from similar to 160 to 1100 ng/dry weight. Invertebrates contained higher concentrations of total PAHs than fish, with naphthalene being the largest contributor. Diagnostic ratios of various PAH compounds in our samples do not suggest crude oil as the main source of PAHs, Other sources of PAHs to the region include rivers outflow, coastline erosion, oil seeps, diagenesis, and long-range atmospheric transport. Organochlorine contaminants were consistently found in our samples at concentrations generally lower than those found in other parts of the United States, (137)Cesium (Cs) was found in measurable amounts in all sediments and biota samples. Isotopic ratios showed that radionuclides originated most likely from global fallout. Compared to other coastal areas off Alaska, the Arctic, and the conterminous United States, Beaufort Sea contamination appears generally low. Published by Elsevier Science Ltd. C1 NOAA, Silver Spring, MD 20910 USA. Univ Calif Los Alamos Natl Lab, Chem Sci & Technol Div, Los Alamos, NM 87545 USA. RP NOAA, N-ORCA2,1305 EW Highway, Silver Spring, MD 20910 USA. NR 152 TC 28 Z9 32 U1 4 U2 14 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 1999 VL 38 IS 8 BP 702 EP 722 DI 10.1016/S0025-326X(99)00034-X PG 21 WC Environmental Sciences; Marine & Freshwater Biology SC Environmental Sciences & Ecology; Marine & Freshwater Biology GA 237ZL UT WOS:000082686400020 ER PT J AU Taylor, PL Rodgers, JE Shobe, J AF Taylor, PL Rodgers, JE Shobe, J TI Scatter fractions from linear accelerators with x-ray energies from 6 to 24 MV SO MEDICAL PHYSICS LA English DT Article DE shielding; scatter; secondary barriers; megavoltage x rays; Monte Carlo AB Computation of shielding requirements for a linear accelerator must take into account the amount of radiation scattered from the patient to areas outside the primary beam. Currently, the most frequently used data are from NCRP 49 that only includes data for x-ray energies up to 6 MV and angles from 30 degrees to 135 degrees. In this work we have determined by Monte Carlo simulation the scattered fractions of dose for a wide range of energies and angles of clinical significance including 6, 10, 18, and 24 MV and scattering angles from 10 degrees to 150 degrees. Calculations were made for a 400 cm(2) circular field size impinging onto a spherical phantom. Scattered fractions of dose were determined at I m from the phantom. Angles from 10 degrees to 30 degrees are of concern for higher energies where the scatter is primarily in the forward direction. An error in scatter fraction may result in too little secondary shielding near the junction with the primary barrier. The Monte Carlo code ITS (Version 3.0) developed at Sandia National Laboratory and NIST was used to simulate scatter from the patient to the barrier. Of significance was the variation of calculated scattered dose with depth of measurement within the barrier indicating that accurate values may be difficult to obtain. Mean energies of scatter x-ray spectra are presented. (C) 1999 American Association of Physicists in Medicine. [S0094-2405(99)01008-1]. C1 Georgetown Univ, Med Ctr, Dept Radiat Med, Washington, DC 20007 USA. Natl Inst Stand & Technol, Ionizing Radiat Phys Div, Gaithersburg, MD 20899 USA. RP Rodgers, JE (reprint author), Georgetown Univ Hosp, Dept Radiat Med, 3800 Reservoir Rd NW, Washington, DC 20007 USA. NR 9 TC 7 Z9 7 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0094-2405 J9 MED PHYS JI Med. Phys. PD AUG PY 1999 VL 26 IS 8 BP 1442 EP 1446 DI 10.1118/1.598670 PG 5 WC Radiology, Nuclear Medicine & Medical Imaging SC Radiology, Nuclear Medicine & Medical Imaging GA 228DJ UT WOS:000082121600002 PM 10501042 ER PT J AU Lipinski, LJ Hoehr, N Mazur, SJ Dianov, GL Senturker, S Dizdaroglu, M Bohr, VA AF Lipinski, LJ Hoehr, N Mazur, SJ Dianov, GL Senturker, S Dizdaroglu, M Bohr, VA TI Repair of oxidative DNA base lesions induced by fluorescent light is defective in xeroderma pigmentosum group A cells SO NUCLEIC ACIDS RESEARCH LA English DT Article ID CHROMATOGRAPHY-MASS-SPECTROMETRY; TRANSCRIPTION-COUPLED REPAIR; NUCLEOTIDE EXCISION-REPAIR; COLI ENDONUCLEASE-III; IN-VITRO REPAIR; MAMMALIAN-CELLS; SACCHAROMYCES-CEREVISIAE; SUBSTRATE-SPECIFICITY; IONIZING-RADIATION; MOLECULAR-CLONING AB Fluorescent light (FL) has been shown to generate free radicals within cells, however, the specific chemical nature of DNA damage induced by FL has not previously been determined. Using gas chromatography/isotope dilution mass spectrometry, we have detected induction of the oxidative DNA lesions 5-hydroxycytosine (5-OH-Cyt), 2,6-diamino-4-hydroxy-5-formamidopyrimidine (FapyGua) and 4,6-diamino-5-formamidopyrimidine (FapyAde) in cultured cells irradiated with FL, We followed the repair of these lesions in normal and xeroderma pigmentosum group A (XP-A) cells. 5-OH-Cyt and FapyGua were repaired efficiently in normal cells within 6 h following FL exposure. XP-A cells were unable to repair these oxidative DNA base lesions. Additionally, to compare the repair of oxidative lesions induced by various sources, in vitro repair studies were performed using plasmid DNA damaged by FL, gamma-irradiation or OsO4 treatment. Whole cell extracts from normal cells repaired damaged substrates efficiently, whereas there was little repair in XP-A extracts, Our data demonstrate defective repair of oxidative DNA base lesions in XP-A cells in vivo and in vitro. C1 NIA, Mol Genet Lab, NIH, Baltimore, MD 21224 USA. Natl Inst Stand & Technol, Chem Sci & Technol Lab, Gaithersburg, MD 20899 USA. RP Bohr, VA (reprint author), NIA, Mol Genet Lab, NIH, Baltimore, MD 21224 USA. NR 47 TC 36 Z9 36 U1 1 U2 1 PU OXFORD UNIV PRESS PI OXFORD PA GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND SN 0305-1048 J9 NUCLEIC ACIDS RES JI Nucleic Acids Res. PD AUG 1 PY 1999 VL 27 IS 15 BP 3153 EP 3158 DI 10.1093/nar/27.15.3153 PG 6 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 223GQ UT WOS:000081832900021 PM 10454612 ER PT J AU Sastry, S Debenedetti, PG Stillinger, FH Schroder, TB Dyre, JC Glotzer, SC AF Sastry, S Debenedetti, PG Stillinger, FH Schroder, TB Dyre, JC Glotzer, SC TI Potential energy landscape signatures of slow dynamics in glass forming liquids SO PHYSICA A LA English DT Article; Proceedings Paper CT International Conference on Statistical Physics (Statphys - Calcutta III) CY JAN 04-09, 1999 CL SATYENDRA NATH BOSE NAT CTR BASIC SCI, SALT LAKE, INDIA HO SATYENDRA NATH BOSE NAT CTR BASIC SCI ID LENNARD-JONES LIQUID; SUPERCOOLED LIQUIDS; MEAN-FIELD; TRANSITION; SYSTEM; NETWORK; MINIMA; MODEL AB We study the properties of local potential energy minima (inherent structures') sampled by liquids at low temperatures as an approach to elucidating the mechanisms of the observed dynamical slowing down observed as the glass transition temperature is approached. This onset of slow dynamics is accompanied by the sampling of progressively deeper potential energy minima. Further, evidence is found in support of a qualitative change in the inherent structures sampled in a temperature range that includes the mode coupling critical temperature T-c, such that a separation of vibrational relaxation within inherent structure basins from that due to inter-basin transitions becomes valid at temperatures T < T-c, Average inherent structure energies do not show any qualitatively significant system size dependence. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Jawaharlal Nehru Ctr Adv Sci Res, Bangalore 560064, Karnataka, India. Princeton Univ, Dept Chem Engn, Princeton, NJ 08544 USA. Lucent Technol, Bell Labs, Murray Hill, NJ 07974 USA. Princeton Univ, Princeton Mat Inst, Princeton, NJ 08544 USA. NIST, Ctr Theoret & Computat Mat Sci, Gaithersburg, MD 20899 USA. Roskilde Univ Ctr, Dept Math & Phys, IMFUFA, DK-4000 Roskilde, Denmark. NIST, Div Polymers, Gaithersburg, MD 20899 USA. RP Sastry, S (reprint author), Jawaharlal Nehru Ctr Adv Sci Res, Jakkar Campus, Bangalore 560064, Karnataka, India. RI Dyre, Jeppe/L-5000-2015 OI Dyre, Jeppe/0000-0002-0770-5690 NR 30 TC 31 Z9 31 U1 0 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0378-4371 J9 PHYSICA A JI Physica A PD AUG 1 PY 1999 VL 270 IS 1-2 BP 301 EP 308 DI 10.1016/S0378-4371(99)00259-9 PG 8 WC Physics, Multidisciplinary SC Physics GA 231PQ UT WOS:000082319300038 ER PT J AU Musielok, J Pawelec, E Griesmann, U Wiese, WL AF Musielok, J Pawelec, E Griesmann, U Wiese, WL TI Atomic transition probabilities of FI spectral lines from 3s-3p and 3p-3d transition arrays SO PHYSICAL REVIEW A LA English DT Article ID SPECTROSCOPIC COUPLING SCHEME; NEUTRAL FLUORINE; LIFETIMES; TESTS; 3P; 3D AB We have measured the relative transition probabilities of about 100 3s-3p and 3p-3d lines of neutral fluorine in the visible and near-infrared spectrum with a wall-stabilized high-current are, which is operated under conditions very dose to partial local thermodynamic equilibrium. The set of measured lines includes about 40 intersystem transitions. Our data have been placed on an absolute scale by normalizing several strong transitions to the results of the OPACITY Project calculations, which are expected to be quite accurate for such transitions. We estimate that the uncertainties of our absolute transition probability values are in the +/- 15% to +/- 20% range, while the uncertainties of the relative values do not exceed 6%, except for very weak transitions. Our results indicate that especially for 3p-3d transitions appreciable departures from LS coupling are encountered. Comparisons with other results indicate that earlier experimental data agree well with ours on a relative scale, but need to be renormalized. [S1050-2947(99)03408-3]. C1 Opole Univ, Inst Phys, PL-45052 Opole, Poland. Jagiellonian Univ, Inst Phys, PL-30050 Krakow, Poland. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Musielok, J (reprint author), Opole Univ, Inst Phys, PL-45052 Opole, Poland. NR 20 TC 18 Z9 19 U1 0 U2 3 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD AUG PY 1999 VL 60 IS 2 BP 947 EP 955 DI 10.1103/PhysRevA.60.947 PG 9 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 227BU UT WOS:000082058900033 ER PT J AU Brown, JM Evenson, KM AF Brown, JM Evenson, KM TI Direct measurement of the fine-structure interval of Al-27 in its ground P-2 state SO PHYSICAL REVIEW A LA English DT Article ID LASER MAGNETIC-RESONANCE; HYPERFINE-STRUCTURE; ENERGY-LEVELS; ALUMINUM; BEAM AB The J=3/2<--1/2 fine-structure transition in atomic Al-27 in its ground P-2 state has been detected in the laboratory by far-infrared laser magnetic resonance. The fine-structure interval has been measured accurately as 3359.6228(17) GHz or 112.064 95(6) cm(-1). The spectra show the hyperfine structure associated with a nuclear spin of 5/2 for Al-27. The splittings are well reproduced by the hyperfine parameters determined earlier by atomic beam methods. The analysis of the laser magnetic-resonance spectra casts doubt on the published value for the Zeeman parameter g(3/2) also from the atomic beam measurements. Although the value determined in this paper is intrinsically much less accurate, it is in better agreement with the value obtained by a completely independent theoretical calculation. [S1050-2947(99)10307-X]. C1 Phys & Theoret Chem Lab, Oxford OX1 3QZ, England. Natl Inst Stand & Technol, Div Time & Frequency, Boulder, CO 80303 USA. RP Phys & Theoret Chem Lab, S Parks Rd, Oxford OX1 3QZ, England. EM jmb@physchem.ox.ac.uk NR 28 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 2469-9926 EI 2469-9934 J9 PHYS REV A JI Phys. Rev. A PD AUG PY 1999 VL 60 IS 2 BP 956 EP 961 DI 10.1103/PhysRevA.60.956 PG 6 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 227BU UT WOS:000082058900034 ER PT J AU Yurovsky, VA Ben-Reuven, A Julienne, PS Williams, CJ AF Yurovsky, VA Ben-Reuven, A Julienne, PS Williams, CJ TI Atom loss from Bose-Einstein condensates due to Feshbach resonance SO PHYSICAL REVIEW A LA English DT Article ID COLLISIONS AB In recent experiments on Na Bose-Einstein condensates [S. Inouye et al., Nature 392, 151 (1998); J. Stenger et al., Phys. Rev. Lett. 82, 2422 (1999)], large loss rates were observed when a time-varying magnetic field was used to tune a molecular Feshbach resonance state near the state of atom pairs that belong to the condensate many-body wave function. A mechanism is offered here to account for the observed losses. It is based on the deactivation of the resonant molecular state by interaction with a third condensate atom, with a deactivation rate coefficient of magnitude similar to 10(-10) cm(3)/s. [S1050-2947(99)50508-8]. C1 Tel Aviv Univ, Sch Chem, IL-69978 Tel Aviv, Israel. Natl Inst Stand & Technol, Atom Phys Div, Gaithersburg, MD 20899 USA. RP Yurovsky, VA (reprint author), Tel Aviv Univ, Sch Chem, IL-69978 Tel Aviv, Israel. RI Williams, Carl/B-5877-2009; Julienne, Paul/E-9378-2012 OI Julienne, Paul/0000-0002-5494-1442 NR 14 TC 59 Z9 59 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD AUG PY 1999 VL 60 IS 2 BP R765 EP R768 DI 10.1103/PhysRevA.60.R765 PG 4 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 227BU UT WOS:000082058900010 ER PT J AU Mizel, A Benedict, LX Cohen, ML Louie, SG Zettl, A Budraa, NK Beyermann, WP AF Mizel, A Benedict, LX Cohen, ML Louie, SG Zettl, A Budraa, NK Beyermann, WP TI Analysis of the low-temperature specific heat of multiwalled carbon nanotubes and carbon nanotube ropes SO PHYSICAL REVIEW B LA English DT Article ID CAPACITY; DYNAMICS AB We analyze specific-heat measurements in the temperature range 1 1.6 x 10(-4) for a temperature jump from T-i to T-0 is significantly different from the value obtained for the temperature jump from T-j to T-0. The temperatures T-i or T-j can be either greater or less than T-0. If the hypothesis is rejected, the tau(eff)-paradox and expansion gap need to be rethought. If the hypothesis is accepted, then the argument that reproduction of the expansion gap is an important test of structural recovery models is strengthened. Our analysis leads to the conclusion that the extensive set of data obtained at 40 degrees C support the existence of an expansion gap, hence an apparently paradoxical value of tau(eff), for values of \delta\ greater than or equal to 1.6 x 10(-4). However, at smaller values of \delta\ it appears that the values of tau(eff) are no longer statistically different and, in fact, the data suggest that as \delta\ --> 0 all of the tau(eff) values converge. In addition, data for experiments at 35 degrees C do not have sufficient accuracy to support the expansion gap for such small values of \delta\ because the duration of the experiments is significantly longer than those at 40 degrees C. Consequently the data readings taken at 35 degrees C were made at longer time intervals and this leads to dramatically reduced error correlations. (C) 1999 Published by Elsevier Science Ltd. All rights reserved. C1 NIST, Div Polymers, Gaithersburg, MD 20899 USA. NIST, Stat Engn Div, Gaithersburg, MD 20899 USA. Inst Charles Sadron, F-67083 Strasbourg, France. RP McKenna, GB (reprint author), NIST, Div Polymers, Gaithersburg, MD 20899 USA. RI McKenna, Gregory/O-1134-2013 OI McKenna, Gregory/0000-0002-5676-9930 NR 23 TC 26 Z9 26 U1 0 U2 11 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0032-3861 J9 POLYMER JI Polymer PD AUG PY 1999 VL 40 IS 18 BP 5183 EP 5205 DI 10.1016/S0032-3861(98)00668-5 PG 23 WC Polymer Science SC Polymer Science GA 198VH UT WOS:000080444600021 ER PT J AU Kracker, LM AF Kracker, LM TI The geography of fish: The use of remote sensing and spatial analysis tools in fisheries research SO PROFESSIONAL GEOGRAPHER LA English DT Article DE spatial analysis; remote sensing; aquatic ecology; fisheries acoustics; oceans ID LAKE-ONTARIO; CHESAPEAKE BAY; PREDATOR; ATLANTIC; ECOLOGY; GROWTH; GIS; DISTRIBUTIONS; TEMPERATURE; ABUNDANCE AB Rather than seeing the oceans as an expansive void, researchers using acoustic technologies can detect the heterogeneity of biological resources and view the marine environment as a three-dimensional landscape. Underwater remote sensing, using acoustics, provides high resolution maps of the spatial distribution of organisms in aquatic ecosystems. Analyzing the spatial pattern of species distribution within the water column and the impact of that organization on ecological processes bridges the fields of fisheries and spatial analysis. Tools and concepts familiar to geographers, such as remote sensing, GIS, and landscape ecology, contribute to the investigation of large lake and marine ecosystems. C1 NOAA, Natl Ocean Serv, Ctr Coastal Enivironm Hlth & Biomol Res, Charleston, SC 29412 USA. RP Kracker, LM (reprint author), NOAA, Natl Ocean Serv, Ctr Coastal Enivironm Hlth & Biomol Res, Charleston, SC 29412 USA. NR 55 TC 13 Z9 15 U1 1 U2 11 PU BLACKWELL PUBLISHERS PI MALDEN PA 350 MAIN STREET, STE 6, MALDEN, MA 02148 USA SN 0033-0124 J9 PROF GEOGR JI Prof. Geogr. PD AUG PY 1999 VL 51 IS 3 BP 440 EP 450 DI 10.1111/0033-0124.00178 PG 11 WC Geography SC Geography GA 221FQ UT WOS:000081714000010 ER PT J AU Davies, AN Heller, SR Jost, JW AF Davies, AN Heller, SR Jost, JW TI Guidelines for the use of the Internet by IUPAC bodies (technical report) SO PURE AND APPLIED CHEMISTRY LA English DT Article C1 ISAS, Inst Spektrochem, D-44013 Dortmund, Germany. NIST, SRD, Gaithersburg, MD 20899 USA. IUPAC Secretariat, Res Triangle Pk, NC 27709 USA. RP Davies, AN (reprint author), ISAS, Inst Spektrochem, Postfach 10 13 52, D-44013 Dortmund, Germany. NR 0 TC 0 Z9 0 U1 0 U2 0 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD OX2 0NE, OXON, ENGLAND SN 0033-4545 J9 PURE APPL CHEM JI Pure Appl. Chem. PD AUG PY 1999 VL 71 IS 8 BP 1587 EP 1591 DI 10.1351/pac199971081587 PG 5 WC Chemistry, Multidisciplinary SC Chemistry GA 296GL UT WOS:000086016000023 ER PT J AU Vocke, RD AF Vocke, RD TI Atomic weights of the elements 1997 (technical report) SO PURE AND APPLIED CHEMISTRY LA English DT Article ID OXYGEN ISOTOPES; MURCHISON METEORITE; HALF-LIVES; GRAINS; NUCLEOSYNTHESIS; MINERALOGY; ABUNDANCES; CHEMISTRY; NUCLIDES; RATIOS AB The biennial review of atomic weight determinations, A(r)(E), and other cognate data has warranted no changes for the standard atomic weights of the elements from that previously published in the Table of Atomic Weights 1995 with the exception of a new footnote for lithium. The names for the transfermium elements with atomic numbers 101-109 have been officially adopted, and element 112 has been synthesized. Many elements in nonterrestrial matter have isotopic compositions different from those in similar terrestrial substances that may affect their atomic weight. Some recent isotopic data on xenon and oxygen in nonterrestrial materials are included in this report together with a discussion of the possible processes causing these changes. C1 NIST, Gaithersburg, MD 20899 USA. RP Vocke, RD (reprint author), NIST, Gaithersburg, MD 20899 USA. NR 35 TC 39 Z9 40 U1 1 U2 3 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD OX2 0NE, OXON, ENGLAND SN 0033-4545 J9 PURE APPL CHEM JI Pure Appl. Chem. PD AUG PY 1999 VL 71 IS 8 BP 1593 EP 1607 DI 10.1351/pac199971081593 PG 15 WC Chemistry, Multidisciplinary SC Chemistry GA 296GL UT WOS:000086016000024 ER PT J AU McLaughlin, WL Puhl, JM Kovacs, A Baranyai, M Slezsak, I Saylor, MC Saylor, SA Miller, SD Murphy, M AF McLaughlin, WL Puhl, JM Kovacs, A Baranyai, M Slezsak, I Saylor, MC Saylor, SA Miller, SD Murphy, M TI Sunna dosimeter: an integrating photoluminescent film and reader system; work in progress SO RADIATION PHYSICS AND CHEMISTRY LA English DT Article; Proceedings Paper CT 9th Tihany Symposium on Radiation Chemistry CY AUG 29-SEP 03, 1998 CL TATABANYA, HUNGARY ID LUMINESCENCE DOSIMETRY AB A new radiation dosimeter, consisting of an optically-stimulated polymer film containing a photofluorescent sensor, can serve as a routine dosimeter and radiographic imaging medium for high-dose applications in the absorbed dose range 0.1-100 kGy. The flexible, colorless, opalescent film having a uniform thickness of 0.240 (+/- 0.005) mm or certain other films in the thickness range 0.08-0.60 mm, are available in large batches. They can be read rapidly with a simple table-top spectrofluorimeter, excitation wavelength (lambda = 450 nm) and emission wavelength (lambda = 670 nm), giving a type A uncertainty of dose evaluation of < +/- 5% at 95% confidence level. It supplies either,single integrated dose readings or two-dimensional radiographic images with relatively high spatial resolution. The present work focuses on the following gamma-ray response characteristics of the system: inter- and intra-batch reproducibility, pre- and post-irradiation stability, and dependence of dose interpretations on absorbed dose rate and irradiation temperature. (C) 1999 Elsevier Science Ltd, All rights reserved. C1 NIST, Ionizing Radiat Div, Phys Lab, Gaithersburg, MD 20899 USA. Hungarian Acad Sci, Inst Isotopes & Surface Chem, H-1525 Budapest, Hungary. Sensolab Ltd, God, Hungary. Special Proc Serv, Dunn Loring, VA 22027 USA. Sunna Syst Corp, Richland, WA 99352 USA. RP McLaughlin, WL (reprint author), NIST, Ionizing Radiat Div, Phys Lab, Gaithersburg, MD 20899 USA. NR 10 TC 13 Z9 13 U1 0 U2 4 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0969-806X J9 RADIAT PHYS CHEM JI Radiat. Phys. Chem. PD AUG PY 1999 VL 55 IS 5-6 BP 767 EP 771 DI 10.1016/S0969-806X(99)00227-3 PG 5 WC Chemistry, Physical; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical SC Chemistry; Nuclear Science & Technology; Physics GA 221YN UT WOS:000081755600057 ER PT J AU Ebraheem, S Beshir, WB Kovacs, A Wojnarovits, L McLaughlin, WL AF Ebraheem, S Beshir, WB Kovacs, A Wojnarovits, L McLaughlin, WL TI A new spectrophotometric readout for the alanine-triphenyl tetrazolium chloride system for high-dose dosimetry SO RADIATION PHYSICS AND CHEMISTRY LA English DT Article; Proceedings Paper CT 9th Tihany Symposium on Radiation Chemistry CY AUG 29-SEP 03, 1998 CL TATABANYA, HUNGARY AB The electron spin resonance (ESR) readout of radical concentration in irradiated L-alanine is well known as a transfer dosimetry system, however, the high cost of the ESR equipment is a serious handicap for large-scale routine application. In this study the reaction between irradiated L-alanine powder and aqueous solution of triphenyl tetrazolium chloride (TTC) was studied. The radical produced by irradiation of alanine reacts during the dissolution with TTC forming pink-colored formazans with absorption maxima around 401 and 487 nm. This readout method can be used in the 2-200 kGy dose range. (C) 1999 Published by Elsevier Science Ltd. All rights reserved. C1 Natl Ctr Radiat Res & Technol, Cairo, Egypt. Hungarian Acad Sci, Chem Res Ctr, Inst Isotope & Surface Chem, H-1525 Budapest, Hungary. NIST, Phys Lab, Gaithersburg, MD 20899 USA. RP Ebraheem, S (reprint author), Natl Ctr Radiat Res & Technol, POB 29, Cairo, Egypt. NR 11 TC 5 Z9 5 U1 0 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0969-806X J9 RADIAT PHYS CHEM JI Radiat. Phys. Chem. PD AUG PY 1999 VL 55 IS 5-6 BP 785 EP 787 DI 10.1016/S0969-806X(99)00228-5 PG 3 WC Chemistry, Physical; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical SC Chemistry; Nuclear Science & Technology; Physics GA 221YN UT WOS:000081755600060 ER PT J AU Kovacs, A Wojnarovits, L Baranyai, M Moussa, A Othman, I McLaughlin, WL AF Kovacs, A Wojnarovits, L Baranyai, M Moussa, A Othman, I McLaughlin, WL TI Radiolytic reactions of nitro blue tetrazolium under oxidative and reductive conditions: a pulse radiolysis study SO RADIATION PHYSICS AND CHEMISTRY LA English DT Article; Proceedings Paper CT 9th Tihany Symposium on Radiation Chemistry CY AUG 29-SEP 03, 1998 CL TATABANYA, HUNGARY ID CHLORIDE AB The radiolytic reactions of the ditetrazolium salt nitro blue tetrazolium chloride (NBTCl2) were studied by pulse radiolysis technique in aqueous solution under reducing and oxidising conditions with the aim of potential dosimetry application. Under reducing conditions the fast formation of the tetrazolinyl radical is observed that is followed by the appearance of monoformazan (MF+), i.e. one of the tetrazolium rings is reduced to formazan. The formation of the water-insoluble diformazan, i.e, the result of the second reduction step was not observed in pulse radiolysis. Formazan formation was not found under oxidative conditions. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Hungarian Acad Sci, Chem Res Ctr, Inst Isotope & Surface Chem, H-1525 Budapest, Hungary. Syrian Atom Energy Commiss, Damascus, Syria. NIST, Gaithersburg, MD 20899 USA. RP Kovacs, A (reprint author), Hungarian Acad Sci, Chem Res Ctr, Inst Isotope & Surface Chem, POB 77, H-1525 Budapest, Hungary. NR 9 TC 17 Z9 18 U1 0 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0969-806X J9 RADIAT PHYS CHEM JI Radiat. Phys. Chem. PD AUG PY 1999 VL 55 IS 5-6 BP 795 EP 798 DI 10.1016/S0969-806X(99)00230-3 PG 4 WC Chemistry, Physical; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical SC Chemistry; Nuclear Science & Technology; Physics GA 221YN UT WOS:000081755600062 ER PT J AU Kovacs, A Baranyai, M Wojnarovits, L Moussa, A Othman, I McLaughlin, WL AF Kovacs, A Baranyai, M Wojnarovits, L Moussa, A Othman, I McLaughlin, WL TI Aqueous-ethanol nitro blue tetrazolium solutions for high dose dosimetry SO RADIATION PHYSICS AND CHEMISTRY LA English DT Article; Proceedings Paper CT 9th Tihany Symposium on Radiation Chemistry CY AUG 29-SEP 03, 1998 CL TATABANYA, HUNGARY AB The ions of nitro blue tetrazolium (NBT2+) in aqueous ethanol solution are readily reduced radiolytically first to monoformazan (MF+) and then to diformazan (DF) having high linear molar extinction coefficients at the absorption maxima of similar to 522 and similar to 570-610 nm. Spectrophotometric analysis then provides potential use in high-dose dosimetry over the dose ranges of 0.1-1 and 1-30 kGy. The solution is stable for the first 24 h after the irradiation. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Hungarian Acad Sci, Chem Res Ctr, Inst Isotope & Surface Chem, H-1525 Budapest, Hungary. Syrian Atom Energy Commiss, Damascus, Syria. NIST, Phys Lab, Ionizing Radiat Div, Gaithersburg, MD 20899 USA. RP Kovacs, A (reprint author), Hungarian Acad Sci, Chem Res Ctr, Inst Isotope & Surface Chem, POB 77, H-1525 Budapest, Hungary. NR 5 TC 23 Z9 23 U1 0 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0969-806X J9 RADIAT PHYS CHEM JI Radiat. Phys. Chem. PD AUG PY 1999 VL 55 IS 5-6 BP 799 EP 803 DI 10.1016/S0969-806X(99)00231-5 PG 5 WC Chemistry, Physical; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical SC Chemistry; Nuclear Science & Technology; Physics GA 221YN UT WOS:000081755600063 ER PT J AU Kirkpatrick, PE Ekin, JW Bray, SL AF Kirkpatrick, PE Ekin, JW Bray, SL TI A flexible high-current lead for use in high-magnetic-field cryogenic environments SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article ID SUPERCONDUCTORS; NB3SN AB A flexible high-current lead for use at cryogenic temperatures and in high-magnetic fields has been developed using high purity aluminum. Readily available high purity aluminum has distinct advantages over copper, namely lower resistivity at liquid-helium temperature, lower magnetoresistance, lower yield stress, lower density, lower cost for material with comparable conductivity, and room temperature annealing. Aluminum may also be used in high magnetic fields, where flexible superconductors cease to function. Practical issues encountered in the design and fabrication of such flexible leads are discussed, such as geometrical considerations where sample loading and heating are important issues. (C) 1999 American Institute of Physics. [S0034-6748(99)03908-8]. C1 Univ Colorado, Boulder, CO 80309 USA. Natl Inst Stand & Technol, Boulder, CO 80303 USA. RP Kirkpatrick, PE (reprint author), Univ Colorado, Boulder, CO 80309 USA. NR 15 TC 10 Z9 10 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD AUG PY 1999 VL 70 IS 8 BP 3338 EP 3340 DI 10.1063/1.1149915 PG 3 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 221HE UT WOS:000081720900023 ER PT J AU Thomson, RE AF Thomson, RE TI Low-temperature atomic force microscope using piezoresistive cantilevers SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article ID FIBER INTERFEROMETER; ULTRAHIGH-VACUUM; RESOLUTION AB This article describes the design of an easy-to-operate low-temperature atomic force microscope (AFM) that incorporates piezoresistive cantilevers. The instrument is easier to build and to operate at cryogenic temperatures than AFMs based on laser deflection schemes or interferometers because no mechanical adjustments of the instrument are necessary after a change of temperature. The effects of thermal expansion on the AFM's tip-to-sample distance are minimized by the use of a double tube scanner assembly. The design includes a simple mechanism that locks the sample holder in place as the temperature is lowered. This AFM is compact and rigid, enabling it to be used in a conventional cryogenic liquid-storage Dewar. All of the materials used in the construction of the AFM are ultra-high-vacuum compatible. [S0034-6748(99)01508-7]. C1 Natl Inst Stand & Technol, Div Electromagnet Technol, Boulder, CO 80303 USA. RP Thomson, RE (reprint author), Natl Inst Stand & Technol, Div Electromagnet Technol, Boulder, CO 80303 USA. NR 11 TC 13 Z9 13 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD AUG PY 1999 VL 70 IS 8 BP 3369 EP 3372 DI 10.1063/1.1149945 PG 4 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 221HE UT WOS:000081720900029 ER PT J AU Solomon, S AF Solomon, S TI Stratospheric ozone depletion: A review of concepts and history SO REVIEWS OF GEOPHYSICS LA English DT Review ID IN-SITU MEASUREMENTS; TOTAL REACTIVE NITROGEN; NITRIC-ACID TRIHYDRATE; ARCTIC POLAR VORTEX; NORTHERN-HEMISPHERE WINTER; ATMOSPHERIC ABSORPTION-MEASUREMENTS; AIRBORNE LIDAR OBSERVATIONS; SPRINGTIME ANTARCTIC OZONE; BALLOON-BORNE OBSERVATIONS; MICROWAVE LIMB SOUNDER AB Stratospheric ozone depletion through catalytic chemistry involving man-made chlorofluorocarbons is an area of focus in the study of geophysics and one of the global environmental issues of the twentieth century. This review presents a brief history of the science of ozone depletion and describes a conceptual framework to explain the key processes involved, with a focus on chemistry. Observations that may be considered as evidence (fingerprints) of ozone depletion due to chlorofluorocarbons are explored, and the related gas phase and surface chemistry is described. Observations of ozone and of chlorine-related trace gases near 40 km provide evidence that gas phase chemistry has indeed currently depleted about 10% of the stratospheric ozone there as predicted, and the vertical and horizontal structures of this depletion are fingerprints for that process. More striking changes are observed each austral spring in Antarctica, where about half of the total ozone column is depleted each September, forming the Antarctic ozone hole. Measurements of large amounts of ClO, a key ozone destruction catalyst, are among the finger- prints showing that human releases of chlorofluorocarbons are the primary cause of this change. Enhanced ozone depletion in the Antarctic and Arctic regions is linked to heterogeneous chlorine chemistry that occurs on the surfaces of polar stratospheric clouds at cold temperatures. Observations also show that some of the same heterogeneous chemistry occurs on the surfaces of particles present at midlatitudes as well, and the abundances of these particles are enhanced following explosive volcanic eruptions. The partitioning of chlorine between active forms that destroy ozone and inert reservoirs that sequester it is a central part of the framework for our understanding of the 40-km ozone decline, the Antarctic ozone hole, the recent Arctic ozone losses in particularly cold years, and the observation of record midlatitude ozone depletion after the major eruption of Mount Pinatubo in the early 1990s. As human use of chlorofluorocarbons continues to decrease, these changes throughout the ozone layer are expected to gradually reverse during the twenty-first century. C1 NOAA, Aeron Lab, Boulder, CO 80303 USA. RP Solomon, S (reprint author), NOAA, Aeron Lab, R-E-AL8,325 S Broadway, Boulder, CO 80303 USA. NR 416 TC 825 Z9 858 U1 35 U2 307 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 8755-1209 J9 REV GEOPHYS JI Rev. Geophys. PD AUG PY 1999 VL 37 IS 3 BP 275 EP 316 DI 10.1029/1999RG900008 PG 42 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 224ZT UT WOS:000081930700001 ER EF