FN Thomson Reuters Web of Science™ VR 1.0 PT J AU Escorza-Trevino, S Dizon, AE AF Escorza-Trevino, S Dizon, AE TI Phylogeography, intraspecific structure and sex-biased dispersal of Dall's porpoise, Phocoenoides dalli, revealed by mitochondrial and microsatellite DNA analyses SO MOLECULAR ECOLOGY LA English DT Article DE Dall's porpoise; dispersal; microsatellites; mtDNA; phylogeography; population structure ID WHALE DELPHINAPTERUS-LEUCAS; POPULATION-STRUCTURE; GENETIC DIFFERENTIATION; STATISTICAL POWER; COALESCENT; PHOCOENIDAE; PATTERNS; FLOW AB Mitochondrial DNA (mtDNA) control-region sequences and microsatellite loci length polymorphisms were used to estimate phylogeographical patterns (historical patterns underlying contemporary distribution), intraspecific population structure and gender-biased dispersal of Phocoenoides dalli dalli across its entire range. One-hundred and thirteen animals from several geographical strata were sequenced over 379 bp of mtDNA, resulting in 58 mtDNA haplotypes. Analysis using Fs, values (based on haplotype frequencies) and Phi(ST) values (based on frequencies and genetic distances between haplotypes) yielded statistically significant separation (bootstrap values P < 0.05) among most of the stocks currently used for management purposes. A minimum spanning network of haplotypes showed two very distinctive clusters, differentially occupied by western and eastern populations, with some common widespread haplotypes. This suggests some degree of phyletic radiation from west to east, superimposed on gene flow. Highly male-biased migration was detected for several population comparisons. Nuclear microsatellite DNA markers (119 individuals and six loci) provided additional support for population subdivision and gender-biased dispersal detected in the mtDNA sequences. Analysis using Fs, values (based on allelic frequencies) yielded statistically significant separation between some, but not all, populations distinguished by mtDNA analysis. R-ST values (based on frequencies of and genetic distance between alleles) showed no statistically significant subdivision. Again, highly male-biased dispersal was detected for all population comparisons, suggesting, together with morphological and reproductive data, the existence of sexual selection. Our molecular results argue for nine distinct dalli-type populations that should be treated as separate units for management purposes. C1 SW Fisheries Sci Ctr, La Jolla, CA 92038 USA. Univ Calif San Diego, Scripps Inst Oceanog, La Jolla, CA 92093 USA. RP SW Fisheries Sci Ctr, POB 271,8604 La Jolla Shores Dr, La Jolla, CA 92038 USA. EM sescorza@ucsd.edu NR 46 TC 70 Z9 76 U1 1 U2 19 PU WILEY-BLACKWELL PI HOBOKEN PA 111 RIVER ST, HOBOKEN 07030-5774, NJ USA SN 0962-1083 EI 1365-294X J9 MOL ECOL JI Mol. Ecol. PD AUG PY 2000 VL 9 IS 8 BP 1049 EP 1060 DI 10.1046/j.1365-294x.2000.00959.x PG 12 WC Biochemistry & Molecular Biology; Ecology; Evolutionary Biology SC Biochemistry & Molecular Biology; Environmental Sciences & Ecology; Evolutionary Biology GA 345GF UT WOS:000088807700004 PM 10964224 ER PT J AU Grasso, LD AF Grasso, LD TI The dissipation of a left-moving cell in a severe storm environment SO MONTHLY WEATHER REVIEW LA English DT Article ID THUNDERSTORM; SIMULATION; DYNAMICS; SCHEME; RAMS AB Observations have shown that thunderstorms sometimes undergo updraft splitting, where one updraft moves to the right of the mean tropospheric wind and the other to the left. Observations also show that the left-moving updraft tends to dissipate approximately 15 min after the splitting process. The right-moving cell, however, may exist for up to a few hours. Idealized modeling studies suggest that this behavior is related to the clockwise turning of the environmental shear vectors with height. The interaction between the environmental shear and the storms updraft produces a high-low pressure couplet oriented downshear. This pressure pattern produces favorable vertical accelerations for the right mover. This same process inhibits upward motion for the left mover. In this paper an idealized simulation is presented that suggests an additional process that contributed to the decay of the left-moving updraft. Analysis of low-level storm-relative winds for the left-moving cell indicated that the inflow was from the cool precipitating downdraft. This in-Row was characterized by negatively buoyant air. Subsequently the updraft dissipated approximately 1500 s after the precipitating downdraft formed. In contrast, the inflow for the right-moving updraft was partly from the downdraft and the undisturbed environment. A second simulation was run in which no precipitation was allowed to form, thus no downdraft formed. In that simulation the left mover was long lived. These results suggest that the simulated left-moving cell dissipated by ingesting downdraft air. C1 Colorado State Univ, NOAA, NES, DIS,RAMMT CIRA, Ft Collins, CO 80523 USA. RP Grasso, LD (reprint author), Colorado State Univ, NOAA, NES, DIS,RAMMT CIRA, W Laporte Ave, Ft Collins, CO 80523 USA. NR 15 TC 12 Z9 13 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 AUG PY 2000 VL 128 IS 8 BP 2797 EP 2815 DI 10.1175/1520-0493(2000)128<2797:TDOALM>2.0.CO;2 PN 1 PG 19 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 346BD UT WOS:000088849600010 ER PT J AU Grasso, LD AF Grasso, LD TI A numerical simulation of dryline sensitivity to soil moisture SO MONTHLY WEATHER REVIEW LA English DT Article ID MESOSCALE CONVECTIVE SYSTEM; SEVERE-STORM ENVIRONMENT; OKLAHOMA DRYLINE; EVOLUTION; PARAMETERIZATION; SURFACES; DYNAMICS; INTENSE; SCHEME; MODELS AB Previous studies have explained dryline movement to be a result of vertical turbulent mixing. Such mixing was shown to efficiently erode the western edge of the shallow moist layer above sloping terrain. Two- and three-dimensional simulations have been used to demonstrate the impact of surface physiography on dryline evolution. Those simulations included changes in vegetation type, vegetation coverage, and soil moisture. In particular, dryline morphology has been shown to be dependent on the horizontal distribution of soil moisture. Modeling studies have also suggested that increases in the low-level horizontal water vapor gradient, associated with a dryline, are a result of frontogenetic forcing. The current study will extend past results by including more sensitivity experiments showing the dependence of dryline morphology on soil moisture. In this paper, the Regional Atmospheric Modeling System was used to simulate the 26 April 1991 central plains dryline. Five simulations were conducted in which only soil moisture was varied. Results suggest that the movement of the dryline and the magnitude of the low-level water vapor gradient are sensitive to changes in soil moisture. Results from the constant soil moisture case show little movement of the 9.0 g kg(-1) water vapor mixing ratio isohume during the day. In that simulation the low-level horizontal gradient of water vapor displayed little change with time. Simulated dryline evolution can be viewed as a two-step process. The first is the apparent eastward movement of drier air due to turbulent erosion of the shallow moist layer. The second step is the relatively rapid increase of the low-level horizontal gradient of water vapor. The increase of the gradient was found to be in response to vertically oriented thermally driven solenoids and frontogenetic forcing. C1 Colorado State Univ, NOAA, NES, DIS,RAMMT CIRA, Ft Collins, CO 80523 USA. RP Grasso, LD (reprint author), Colorado State Univ, NOAA, NES, DIS,RAMMT CIRA, W Laporte Ave, Ft Collins, CO 80523 USA. NR 40 TC 28 Z9 29 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 AUG PY 2000 VL 128 IS 8 BP 2816 EP 2834 DI 10.1175/1520-0493(2000)128<2816:ANSODS>2.0.CO;2 PN 1 PG 19 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 346BD UT WOS:000088849600011 ER PT J AU Griffies, SM Hallberg, RW AF Griffies, SM Hallberg, RW TI Biharmonic friction with a Smagorinsky-like viscosity for use in large-scale eddy-permitting ocean models SO MONTHLY WEATHER REVIEW LA English DT Article ID CIRCULATION MODEL; GENERAL-CIRCULATION; COORDINATE; EDDIES; PARAMETERIZATION; THERMOCLINE; ATMOSPHERE; SIMULATION; DYNAMICS AB This paper discusses a numerical closure, motivated from the ideas of Smagorinsky, for use with a biharmonic operator. The result is a highly scale-selective, state-dependent friction operator for use in eddy-permitting geophysical fluid models. This friction should prove most useful for large-scale ocean models in which there are multiple regimes of geostrophic turbulence. Examples are provided from primitive equation geopotential and isopycnal-coordinate ocean models. C1 NOAA, Geophys Fluid Dynam Lab, Princeton, NJ 08542 USA. RP NOAA, Geophys Fluid Dynam Lab, POB 308,Forrestal Campus, Princeton, NJ 08542 USA. EM smg@gfdl.gov NR 40 TC 190 Z9 191 U1 2 U2 14 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 AUG PY 2000 VL 128 IS 8 BP 2935 EP 2946 DI 10.1175/1520-0493(2000)128<2935:BFWASL>2.0.CO;2 PN 2 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 346BF UT WOS:000088849800004 ER PT J AU Fuller, RD Stensrud, DJ AF Fuller, RD Stensrud, DJ TI The relationship between tropical easterly waves and surges over the Gulf of California during the North American monsoon SO MONTHLY WEATHER REVIEW LA English DT Article ID MEXICAN MONSOON; DISTURBANCES; MOUNTAINS; DYNAMICS; ARIZONA; AIR AB Coastally trapped disturbances, which occur over the Gulf of California and are commonly referred to as gulf surges, are an important mechanism in the transport of low-level moisture into the southwestern United States. To determine whether or not gulf surges develop in association with the passage of tropical easterly waves, as hypothesized in previous studies, standard surface observations and European Centre for Medium-Range Weather Forecasts reanalysis data during the months of July and August over a 14-yr period are examined. Results indicate that tropical easterly wave troughs often cross western Mexico 1-3 days prior to surge onset at Yuma, Arizona, indicating a strong correlation between these two events. This analysis documents yet another mechanism by which the Tropics influences convection in the midlatitudes. C1 NOAA, Natl Severe Storms Lab, Norman, OK 73069 USA. Northland Coll, Ashland, WI USA. RP Stensrud, DJ (reprint author), NOAA, Natl Severe Storms Lab, 1313 Halley Circle, Norman, OK 73069 USA. NR 26 TC 53 Z9 53 U1 0 U2 5 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 AUG PY 2000 VL 128 IS 8 BP 2983 EP 2989 DI 10.1175/1520-0493(2000)128<2983:TRBTEW>2.0.CO;2 PN 2 PG 7 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 346BF UT WOS:000088849800009 ER PT J AU Avila, LA Guiney, JL AF Avila, LA Guiney, JL TI Eastern North Pacific hurricane season of 1998 SO MONTHLY WEATHER REVIEW LA English DT Article AB The 1998 eastern North Pacific hurricane season is reviewed. There were 15 tropical cyclones, consisting of nine hurricanes, four tropical storms, and two tropical depressions. During 1998, two tropical cyclones made landfall; Hurricane Isis made two landfalls in Mexico while Tropical Depression Javier dissipated near Cabo Corrientes, Mexico. C1 NOAA, NWS, NCEP, NHC,Trop Predict Ctr, Miami, FL 33165 USA. RP Avila, LA (reprint author), NOAA, NWS, NCEP, NHC,Trop Predict Ctr, 11691 SW 17th Ave, Miami, FL 33165 USA. NR 6 TC 8 Z9 8 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 AUG PY 2000 VL 128 IS 8 BP 2990 EP 3000 DI 10.1175/1520-0493(2000)128<2990:ENPHSO>2.0.CO;2 PN 2 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 346BF UT WOS:000088849800010 ER PT J AU Stensrud, DJ Brooks, HE Du, J Tracton, MS Rogers, E AF Stensrud, DJ Brooks, HE Du, J Tracton, MS Rogers, E TI Comments on "Using ensembles for short-range forecasting" - Reply SO MONTHLY WEATHER REVIEW LA English DT Letter ID PRECIPITATION C1 NOAA, Natl Severe Storms Lab, Norman, OK 73069 USA. NOAA, NWS, Natl Ctr Environm Predict, Camp Springs, MD USA. RP Stensrud, DJ (reprint author), NOAA, Natl Severe Storms Lab, 1313 Halley Circle, Norman, OK 73069 USA. 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 AUG PY 2000 VL 128 IS 8 BP 3021 EP 3023 DI 10.1175/1520-0493(2000)128<3021:R>2.0.CO;2 PN 2 PG 3 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 346BF UT WOS:000088849800016 ER PT J AU Davies, MA Balachandran, B AF Davies, MA Balachandran, B TI Impact dynamics in milling of thin-walled structures SO NONLINEAR DYNAMICS LA English DT Article DE milling chatter; impact; tool-workpiece interactions; dimension calculation ID CHATTER AB The development of reliable high-speed spindles and motion control systems has led to an increase in the industrial use of high-speed milling. One of the primary applications of this new technology is the manufacture of thin-walled aluminum components for aircraft. The flexibility of the tools and workpieces, the high spindle frequencies, and the inherent impact nonlinearities in the milling process can lead to complicated dynamic tool-workpiece interactions. An experiment was constructed to study the vibrations of a thin-walled part during milling. Time series, power spectra, autocorrelations, auto-bispectra, and phase portraits were examined. From this data, it is inferred that stiffness and damping nonlinearities due to the intermittent cutting action have a pronounced effect on the dynamics of the workpiece. Delay space reconstructions and pointwise dimension calculations show that the associated motions are characterized by a fractal geometry. The auto-bispectra suggest quadratic phase coupling among the spectral peaks associated with the cutter frequency. A mechanics-based model with impact-nonlinearities was developed to explain the observed results. The predicted results agree well with the experimental observations. The model predictions indicate that aperiodic motions are possible over a large range of control-parameter values. These analytical and experimental results have implications for the prediction and control of vibrations in milling. C1 Natl Inst Stand & Technol, Mfg Engn Lab, Gaithersburg, MD 20899 USA. Univ Maryland, Dept Mech Engn, College Pk, MD 20742 USA. RP Davies, MA (reprint author), Natl Inst Stand & Technol, Mfg Engn Lab, Gaithersburg, MD 20899 USA. NR 23 TC 41 Z9 44 U1 4 U2 26 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0924-090X J9 NONLINEAR DYNAM JI Nonlinear Dyn. PD AUG PY 2000 VL 22 IS 4 BP 375 EP 392 DI 10.1023/A:1008364405411 PG 18 WC Engineering, Mechanical; Mechanics SC Engineering; Mechanics GA 350YX UT WOS:000089130200005 ER PT J AU Ovchinnikov, YB AF Ovchinnikov, YB TI Revivals of light in a planar metal waveguide SO OPTICS COMMUNICATIONS LA English DT Article ID WAVE-PACKETS; BEAM-SPLITTERS; DYNAMICS AB The revivals (Fourier images) and fractionals revival (Fresnel images) of the spatial distributions of monochromatic light in a planar, metal, multimode waveguide are investigated theoretically and experimentally. The decomposition of the spectrum of white light in such a waveguide is observed. (C) 2000 Published by Elsevier Science B.V. C1 Natl Inst Stand & Technol, Atom Phys Div, Gaithersburg, MD 20899 USA. RP Ovchinnikov, YB (reprint author), Natl Inst Stand & Technol, Atom Phys Div, Stop 8424, Gaithersburg, MD 20899 USA. NR 26 TC 11 Z9 11 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0030-4018 J9 OPT COMMUN JI Opt. Commun. PD AUG 1 PY 2000 VL 182 IS 1-3 BP 35 EP 43 DI 10.1016/S0030-4018(00)00819-1 PG 9 WC Optics SC Optics GA 343TD UT WOS:000088716900005 ER PT J AU Manley, ME McQueeney, RJ Robertson, JL Fultz, B Neumann, DA AF Manley, ME McQueeney, RJ Robertson, JL Fultz, B Neumann, DA TI Phonon densities of states of gamma-cerium and delta-cerium measured by time-of-flight inelastic neutron scattering SO PHILOSOPHICAL MAGAZINE LETTERS LA English DT Article ID VIBRATIONAL ENTROPY; ELECTRONIC-STRUCTURE; DISORDERED NI3AL; CE; APPROXIMATION; PRESSURE; ALLOYS AB Time-of-flight inelastic neutron scattering spectra were measured on cerium metal at temperatures near. the fee (gamma)-to-bcc (delta) transition temperature. Phonon density-of-slates (DOS) curves were extracted from data acquired over a wide range of momentum transfers. A large softening of the phonon DOS was found in going from gamma-cerium to delta-cerium, and this accounts for an increase in vibrational entropy of (0.71 +/- 0.05)k(B)/atom. To be consistent with the latent heat of the gamma-delta transition, this increase in vibrational entropy must be accompanied by a large decrease in electronic entropy. The results not only confirm the recent discovery of a significant electronic contribution to the gamma-delta transition but also suggest that it may be twice that previously reported. C1 CALTECH, Pasadena, CA 91125 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Manley, ME (reprint author), CALTECH, MS 138-78, Pasadena, CA 91125 USA. RI Manley, Michael/N-4334-2015; McQueeney, Robert/A-2864-2016 OI McQueeney, Robert/0000-0003-0718-5602 NR 23 TC 12 Z9 13 U1 1 U2 2 PU TAYLOR & FRANCIS LTD PI LONDON PA 11 NEW FETTER LANE, LONDON EC4P 4EE, ENGLAND SN 0950-0839 J9 PHIL MAG LETT JI Philos. Mag. Lett. PD AUG PY 2000 VL 80 IS 8 BP 591 EP 596 DI 10.1080/09500830050110530 PG 6 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Physics, Applied; Physics, Condensed Matter SC Materials Science; Metallurgy & Metallurgical Engineering; Physics GA 343HQ UT WOS:000088697300011 ER PT J AU Dzierzega, K Volz, U Nave, G Griesmann, U AF Dzierzega, K Volz, U Nave, G Griesmann, U TI Accurate transition rates for the 5p-5s transitions in KrI SO PHYSICAL REVIEW A LA English DT Article ID RADIATIVE LIFETIMES; PROBABILITIES; DEACTIVATION; STATES AB Branching fractions were measured for electric-dipole transitions from the 5p upper levels to the 5s levels in neutral krypton atoms. The measurements were made with a wall-stabilized electric are and a 2-m monochromator for the spectral lines in the visible, and with a hollow cathode lamp and the NIST 2-m Fourier-transform spectrometer for the lines in the near infrared. A semiempirical calculation, based on accurately known lifetimes for six upper levels, was used to calculate lifetimes for which accurate measurements do not exist. This resulted in a complete set of lifetimes for all 5p levels. Branching fractions and lifetimes were used to calculate transition rates for the 5p-5s transitions. The relative uncertainties of the transition rates range from less than 1% for the strongest lines to about 10% for the weakest lines. Our data also reveal that most of the previous measurements appear to have been affected by opacity effects in the light sources. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Jagiellonian Univ, Inst Fizyki M Smoluchowskiego, PL-30059 Krakow, Poland. Univ Kaiserslautern, Fachbereich Phys, D-67653 Kaiserslautern, Germany. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NR 24 TC 14 Z9 14 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 2000 VL 62 IS 2 AR 022505 PG 9 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 343CD UT WOS:000088683400043 ER PT J AU Newbury, AS Jelenkovic, BM Bollinger, JJ Wineland, DJ AF Newbury, AS Jelenkovic, BM Bollinger, JJ Wineland, DJ TI Simulation of a method for forming a laser-cooled positron plasma SO PHYSICAL REVIEW A LA English DT Article ID PURE ELECTRON-PLASMA; EXTREMELY COLD POSITRONS; NONNEUTRAL ION PLASMA; ANTIHYDROGEN PRODUCTION; PENNING TRAP; SURFACES; REEMISSION; MOLECULES; ROTATION; CRYSTAL AB We have simulated the trapping and cooling of moderated positrons in a Penning trap in which the positrons lose energy through collisions with a simultaneously stored laser-cooled Be-9(+) plasma. Once the positrons are trapped, they cool through sympathetic cooling with the Be-9(+) plasma After the positrons cool, their motion parallel to the magnetic field reaches a state of thermal equilibrium with the Be-9(+) ions and they rotate about the trap axis at the same frequency as the Be-9(+) ions. Therefore, a centrifugal separation will occur, forcing the positrons to coalesce into a cold column along the trap axis. A simulation which, in part, utilizes Monte Carlo techniques, indicates a capture efficiency of as high as 0.3% for 300 K moderated positrons passing through a Be-9(+) plasma with a density of 10(10) atoms cm(-3) and a column length of 1 cm. This capture efficiency leads to the positron capture rate of similar to 1000 positrons per second, assuming a 100 mCi positron source and 10(-3) for the efficiency far moderating positrons from the source. The resulting dense reservoirs of cold positrons may be useful for antihydrogen production and for reaching a plasma state in which the mode dynamics must be treated quantum mechanically. C1 Natl Inst Stand & Technol, Div Time & Frequency, Boulder, CO 80303 USA. MIT, Lincoln Lab, Lexington, MA 02420 USA. Univ Belgrade, Inst Phys, Belgrade, Yugoslavia. RP Newbury, AS (reprint author), Natl Inst Stand & Technol, Div Time & Frequency, Boulder, CO 80303 USA. NR 62 TC 14 Z9 14 U1 1 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD AUG PY 2000 VL 62 IS 2 AR 023405 DI 10.1103/PhysRevA.62.023405 PG 10 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 343CD UT WOS:000088683400079 ER PT J AU Nugent-Glandorf, L Scheer, M Krishnamurthy, M Odom, JW Leone, SR AF Nugent-Glandorf, L Scheer, M Krishnamurthy, M Odom, JW Leone, SR TI Photoelectron spectroscopic determination of the energy bandwidths of high-order harmonics (7th-55th) produced by an ultrafast laser in neon SO PHYSICAL REVIEW A LA English DT Article ID RARE-GASES; HIGH-RESOLUTION; GENERATION; RADIATION; PULSE; PHOTOEMISSION; IONIZATION; CONVERSION; EMISSION; FIELDS AB The energy bandwidths of high-order harmonics of a Ti:sapphire ultrafast laser are extracted from electron kinetic-energy measurements of the photoionization of gas-phase atoms and molecules. High-order harmonics of the 70 fs, 800 nm laser are produced by focusing approximate to 2.5 mi pulses into a jet of neon gas and are frequency-separated by a grazing-incidence grating. Photoelectrons resulting from the ionization of gaseous samples are energy-analyzed with a magnetic bottle time-of-flight spectrometer. Energy broadening of the photoelectron peaks at low kinetic energies are a direct result of the energy bandwidths of the harmonics. The energy bandwidths of the harmonics are found to increase from 0.11(+/- 0.03) eV (7th harmonic) to 0.37(+/- 0.03) eV (45th harmonic) in a gradual manner. The higher-order harmonics (47th-55th) appear to reach a plateau at a value of approximate to 0.43 eV. Though a full theoretical treatment of bandwidths of the harmonics for the 70 fs driving pulse regime does not exist, the theories developed for shorter pulses (less than or equal to 30 fs) can give insight into the observed results. C1 Natl Inst Stand & Technol, JILA, Boulder, CO 80309 USA. Tata Inst Fundamental Res, Mumbai 400005, India. Univ Colorado, Dept Chem & Biochem, Boulder, CO 80309 USA. Univ Colorado, Dept Phys, Boulder, CO 80309 USA. RP Nugent-Glandorf, L (reprint author), Natl Inst Stand & Technol, JILA, Boulder, CO 80309 USA. NR 30 TC 18 Z9 18 U1 0 U2 4 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 2000 VL 62 IS 2 AR 023812 DI 10.1103/PhysRevA.62.023812 PG 8 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 343CD UT WOS:000088683400107 ER PT J AU Trabert, E Calamai, AG Gillaspy, JD Gwinner, G Tordoir, X Wolf, A AF Trabert, E Calamai, AG Gillaspy, JD Gwinner, G Tordoir, X Wolf, A TI Intercombination and forbidden transition rates in C- and N-like ions (O2+, F3+ and S9+) measured at a heavy-ion storage ring SO PHYSICAL REVIEW A LA English DT Article ID CARBON ISOELECTRONIC SEQUENCE; O-III; GROUND-CONFIGURATION; ATOMIC DATA; OSCILLATOR-STRENGTHS; RADIATIVE RATES; IRON PROJECT; I SEQUENCE; PROBABILITIES; LINES AB Rates of an intercombination transition and several electric-dipole forbidden transitions between the levels of the ground complex in C-Like ions of O and F and in N-like ions of S have been measured optically at a heavy-ion storage ring. The lifetime results, 1.250(13) ms for the 2s2p(3) S-5(2)0 level in O2+, 530(25) and 304(5) ms for the 2s(2) 2P(2) S-1(0) level in O2+ and F3+, respectively, and 5.20(15) and 2.10(6) ms for the 2s(2)2p(3) P-2(1/2,3/2)0, levels of S9+, agree with only some of the theoretical predictions, while they have a lower estimated uncertainty than all of them. C1 Ruhr Univ Bochum, D-44780 Bochum, Germany. St Josephs Univ, Dept Phys, Philadelphia, PA 19131 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Max Planck Inst Kernphys, D-69117 Heidelberg, Germany. Univ Liege, IPNE, B-4000 Liege, Belgium. RP Trabert, E (reprint author), Univ Liege, IPNE, Sart Tilman B-15, B-4000 Liege, Belgium. EM elmar@mbox.pne.ulg.ac.be NR 40 TC 9 Z9 9 U1 0 U2 0 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 2000 VL 62 IS 2 AR 022507 PG 8 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 343CD UT WOS:000088683400045 ER PT J AU Trippenbach, M Band, YB Julienne, PS AF Trippenbach, M Band, YB Julienne, PS TI Theory of four-wave mixing of matter waves from a Bose-Einstein condensate SO PHYSICAL REVIEW A LA English DT Article ID DISPERSIVE NONLINEAR MEDIA; ATOMIC PHASE-CONJUGATION; OUTPUT COUPLER; LASER; INTERFERENCE; SCATTERING; DYNAMICS; GAS AB A recent experiment [Deng et at, Nature (London) 398, 218 (1999)] demonstrated four-wave mixing of matter wave packets created from a Bose-Einstein condensate. The experiment utilized light pulses to create two high-momentum wave packets via Bragg diffraction from a stationary Bose-Einstein condensate. The high-momentum components and the initial low-momentum condensate interact to form a new momentum component due to the nonlinear self-interaction of the bosonic atoms. We develop a three-dimensional quantum- mechanical description, based on the slowly-varying-envelope approximation, for four-wave mixing in Bose-Einstein condensates using the time-dependent Gross-Pitaevskii equation. We apply this formulation to describe the experimental observations and to make predictions. We examine the role of phase-modulation, momentum, and energy conservation (i.e., phase matching), and particle number conservation in four-wave mixing of matter waves, and develop simple models for understanding our numerical results. C1 Ben Gurion Univ Negev, Dept Chem, IL-84105 Beer Sheva, Israel. Ben Gurion Univ Negev, Dept Phys, IL-84105 Beer Sheva, Israel. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Trippenbach, M (reprint author), Ben Gurion Univ Negev, Dept Chem, IL-84105 Beer Sheva, Israel. RI Julienne, Paul/E-9378-2012 OI Julienne, Paul/0000-0002-5494-1442 NR 36 TC 75 Z9 75 U1 2 U2 4 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 2000 VL 62 IS 2 AR 023608 DI 10.1103/PhysRevA.62.023608 PG 13 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 343CD UT WOS:000088683400090 ER PT J AU Cockayne, E Burton, BP AF Cockayne, E Burton, BP TI Phonons and static dielectric constant in CaTiO3 from first principles SO PHYSICAL REVIEW B LA English DT Article ID TOTAL-ENERGY CALCULATIONS; WAVE BASIS-SET; AB-INITIO; LATTICE-DYNAMICS; PHASE-TRANSITIONS; BARIUM-TITANATE; PEROVSKITE; POLARIZATION; CERAMICS; SPECTROSCOPY AB CaTiO3 has a static dielectric constant that extrapolates to a value greater than 300 at zero temperature. We investigate the origin of this large dielectric response on a microscopic level, using first-principles plane-wave pseudopotential density functional theory calculations. The electronic dielectric tensor and the complete set of zone center phonons and ionic Born effective charges are determined for CaTiO3 in its low temperature 20-atom per cell orthorhombic phase via frozen phonon electronic structure, polarization, and force constant calculations. Dispersion theory is then used to obtain the dielectric tensor. The dielectric response is dominated by low frequency (v approximate to 90 cm(-1)) polar optical modes in which cation motion opposes oxygen motion. The frequencies of these phonons, and thus the dielectric constant, are predicted to be pressure sensitive. C1 Natl Inst Stand & Technol, Div Ceram, Mat Sci & Engn Lab, Gaithersburg, MD 20899 USA. RP Natl Inst Stand & Technol, Div Ceram, Mat Sci & Engn Lab, Gaithersburg, MD 20899 USA. NR 47 TC 109 Z9 112 U1 6 U2 45 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2469-9950 EI 2469-9969 J9 PHYS REV B JI Phys. Rev. B PD AUG 1 PY 2000 VL 62 IS 6 BP 3735 EP 3743 DI 10.1103/PhysRevB.62.3735 PG 9 WC Physics, Condensed Matter SC Physics GA 343XN UT WOS:000088727900026 ER PT J AU Gallagher, A AF Gallagher, A TI Model of particle growth in silane discharges SO PHYSICAL REVIEW E LA English DT Article ID HYDROGENATED AMORPHOUS-SILICON; LOW-PRESSURE PLASMAS; LIGHT-SCATTERING; NEGATIVE-IONS; DEPOSITION; KINETICS; MICROSCOPY; DEPENDENCE; EMISSION; CLUSTERS AB The growth of silicon particles in the neutral plasma region of pure silane, rf capacitively coupled, steady-state discharges is calculated with a homogeneous, plasma-chemistry model. Plasma conditions are typical of those used in hydrogenated amorphous silicon (a-Si:H) device production. SiH3 and SiH3- grow into particles by the step-by-step addition of silicon atoms, primarily due to reactions with SiH3. Attrition of growing SixHmz radicals and ions with z charges, which are "particles" for large x, occurs by diffusion of neutral and positively charged radicals to the electrodes. Rate coefficients for electron, ion, radical, and silane collisions with the SixHmz for x = 1-10(5) are estimated from detailed considerations of the literature and relevant physics. Self-consistent anion, cation (n(+)), and electron (n(e)) densities and charge fluxes are used, and charge neutrality is maintained. Typically n(+)/n(e)congruent to 100, which causes a large fraction of neutral particles and thereby a major particle flux into the growing a-Si:H film. The density of visible particles (x > 10(4)) varies many orders of magnitude with relatively minor changes in discharge power, pressure, and electrode gap. This parameter dependence agrees with experiment, and by adjusting collision parameters within a reasonable range the calculated particle densities can be brought into exact agreement with experiment. An additional result of the model, which has not yet been detected, is that SixHm clusters with 33.0.CO;2-R PG 4 WC Chemistry, Physical SC Chemistry GA 352VK UT WOS:000089238400076 ER PT J AU Rasch, PJ Feichter, J Law, K Mahowald, N Penner, J Benkovitz, C Genthon, C Giannakopoulos, C Kasibhatla, P Koch, D Levy, H Maki, T Prather, M Roberts, DL Roelofs, GJ Stevenson, D Stockwell, Z Taguchi, S Kritz, M Chipperfield, M Baldocchi, D McMurry, P Barrie, L Balkansi, Y Chatfield, R Kjellstrom, E Lawrence, M Lee, HN Lelieveld, J Noone, KJ Seinfeld, J Stenchikov, G Schwartz, S Walcek, C Williamson, D AF Rasch, PJ Feichter, J Law, K Mahowald, N Penner, J Benkovitz, C Genthon, C Giannakopoulos, C Kasibhatla, P Koch, D Levy, H Maki, T Prather, M Roberts, DL Roelofs, GJ Stevenson, D Stockwell, Z Taguchi, S Kritz, M Chipperfield, M Baldocchi, D McMurry, P Barrie, L Balkansi, Y Chatfield, R Kjellstrom, E Lawrence, M Lee, HN Lelieveld, J Noone, KJ Seinfeld, J Stenchikov, G Schwartz, S Walcek, C Williamson, D TI A comparison of scavenging and deposition processes in global models: results from the WCRP Cambridge Workshop of 1995 SO TELLUS SERIES B-CHEMICAL AND PHYSICAL METEOROLOGY LA English DT Article ID GENERAL-CIRCULATION MODELS; TROPOSPHERIC AEROSOLS; VERTICAL TRANSPORT; RESIDENCE TIMES; CLIMATE MODEL; TRACER MODEL; PB-210; RN-222; SIMULATION; ATMOSPHERE AB We report on results from a World Climate Research Program workshop on representations of scavenging and deposition processes in global transport models of the atmosphere. 15 models were evaluated by comparing simulations of radon, lead, sulfur dioxide, and sulfate against each other, and against observations of these constituents. This paper provides a survey on the simulation differences between models. It identifies circumstances where models are consistent with observations or with each other, and where they differ from observations or with each other. The comparison shows that most models are able to simulate seasonal species concentrations near the surface over continental sites to within a factor of 2 over many regions of the globe. Models tend to agree more closely over source (continental) regions than for remote (polar and oceanic) regions. Model simulations differ most strongly in the upper troposphere for species undergoing wet scavenging processes. There are not a sufficient number of observations to characterize the climatology (long-term average) of species undergoing wet scavenging in the upper troposphere. This highlights the need for either a different strategy for model evaluation (e.g., comparisons on an event by event basis) or many more observations of a few carefully chosen constituents. C1 Natl Ctr Atmospher Res, Boulder, CO 80307 USA. Max Planck Inst Meteorol, D-20146 Hamburg, Germany. Univ Cambridge, Dept Chem, Ctr Atmospher Sci, Cambridge CB2 1EW, England. Univ Calif Santa Barbara, Bren Sch Environm Sci & Management, Santa Barbara, CA 93106 USA. Univ Michigan, Ann Arbor, MI 48109 USA. Brookhaven Natl Lab, Environm Chem Div, Upton, NY 11973 USA. CNRS, LGGE, F-38402 St Martin Dheres, France. Duke Univ, Levine Sci Res Ctr, Sch Environm, Durham, NC 27708 USA. NASA, Goddard Inst Space Studies, New York, NY 10025 USA. GFDL, Princeton, NJ 08542 USA. JMA, Chiyoda Ku, Tokyo 100, Japan. Univ Calif Irvine, Dept Earth Syst Sci, Irvine, CA 92717 USA. Meteorol Off, Bracknell RG12 2SY, Berks, England. Univ Utrecht, IMAU, NL-3584 CC Utrecht, Netherlands. NIRE, Tsukuba, Ibaraki 305, Japan. SUNY Albany, MSRC, New York, NY USA. NOAA, ATDD, Oak Ridge, TN 37831 USA. Univ Minnesota, Minneapolis, MN 55455 USA. AES Downsview, Downsview, ON M3H 5T4, Canada. CEA, DSM, LMCE, F-91191 Gif Sur Yvette, France. MISU, S-10691 Stockholm, Sweden. MPI Chem, D-55122 Mainz, Germany. US DOE, Environm Measurements Lab, New York, NY 10014 USA. Univ Maryland, College Pk, MD 20742 USA. SUNY Albany, Atmospher Sci Res Ctr, Albany, NY 12205 USA. RP Rasch, PJ (reprint author), Natl Ctr Atmospher Res, POB 3000, Boulder, CO 80307 USA. EM pjr@ucar.edu RI McMurry, Peter/A-8245-2008; Baldocchi, Dennis/A-1625-2009; Kasibhatla, Prasad/A-2574-2010; Stevenson, David/C-8089-2012; Schwartz, Stephen/C-2729-2008; Mahowald, Natalie/D-8388-2013; Chipperfield, Martyn/H-6359-2013; Penner, Joyce/J-1719-2012; Georgiy, Stenchikov/J-8569-2013; Giannakopoulos, Christos/H-6827-2014; Lelieveld, Johannes/A-1986-2013 OI Kasibhatla, Prasad/0000-0003-3562-3737; Balkanski, Yves/0000-0001-8241-2858; Kjellstrom, Erik/0000-0002-6495-1038; McMurry, Peter/0000-0003-1609-5131; Baldocchi, Dennis/0000-0003-3496-4919; Stevenson, David/0000-0002-4745-5673; Schwartz, Stephen/0000-0001-6288-310X; Mahowald, Natalie/0000-0002-2873-997X; Chipperfield, Martyn/0000-0002-6803-4149; NR 47 TC 122 Z9 123 U1 0 U2 12 PU CO-ACTION PUBLISHING PI JARFALLA PA RIPVAGEN 7, JARFALLA, SE-175 64, SWEDEN SN 0280-6509 J9 TELLUS B JI Tellus Ser. B-Chem. Phys. Meteorol. PD AUG PY 2000 VL 52 IS 4 BP 1025 EP 1056 DI 10.1034/j.1600-0889.2000.00980.x PG 32 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 361KA UT WOS:000089721200001 ER PT J AU Rozumalski, RA AF Rozumalski, RA TI A quantitative assessment of the NESDIS auto-estimator SO WEATHER AND FORECASTING LA English DT Article ID RAINFALL; MODEL; SKILL AB A systematic evaluation of the National Environmental Satellite, Data and Information Service Auto-Estimator (A-E), a satellite-based algorithm for the estimation of rainfall, was performed for a 13-month period ending December 1998. This effort was intended to serve as an independent benchmark for the assessment of A-E products, as well as to provide a measure of satellite-based precipitation algorithms in general. It is important that the accuracy of the A-E be established, since this algorithm is currently being proposed as the successor to the operational Interactive Flash Flood Analyzer technique used by Satellite Analysis Branch forecasters at the National Centers for Environmental Prediction (NCEP). Furthermore, the results of this assessment will be used to determine whether these satellite-based estimates should be integrated into the current state of NCEP multisensor precipitation analyses. The NCEP stage III precipitation analysis was chosen as the primary "ground truth" for this evaluation following a comparison of available radar-, gauge-, and multisensor-based estimates. This intracomparison demonstrated a good correspondence in the mean precipitation between the stage III and gauge-only datasets. This agreement was consistent for all skill measures evaluated. Radar estimates generally underforecasted the amount of precipitation relative to either the stage III or gauge-only analyses. This underestimation was most dramatic during the cool season when radar estimates were about 50% of the multisensor and gauge amounts. The results from this study show that the A-E exhibits high-amplitude month-to-month fluctuations in its representation of mean areal precipitation compared to those from bias-corrected, multisensor (stage III) and 24-h gauge-only analyses. Overall, the verification results indicate that the skill of the A-E was greatest over 24-h periods and lowest for 1-h periods of accumulations. The algorithm demonstrated little skill overall with the most skill occurring during the warm season (May-August). Moreover, the A-E skill scores displayed a high degree of variability from one accumulation period to the next across the entire suite of temporal and spatial scales evaluated in this study. This variability makes it difficult to place any confidence in the accuracy of precipitation estimates for operational use. C1 NWS Off Meteorol, Silver Spring, MD USA. RP Rozumalski, RA (reprint author), COMET UCAR, POB 3000, Boulder, CO 80307 USA. NR 13 TC 12 Z9 13 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 AUG PY 2000 VL 15 IS 4 BP 397 EP 415 DI 10.1175/1520-0434(2000)015<0397:AQAOTN>2.0.CO;2 PG 19 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 346EX UT WOS:000088858800002 ER PT J AU Rogash, JA Smith, RD AF Rogash, JA Smith, RD TI Multiscale overview of a violent tornado outbreak with attendant flash flooding SO WEATHER AND FORECASTING LA English DT Article ID CONVECTIVE STORMS; THUNDERSTORMS; PROPAGATION; SUPERCELLS; ROTATION; SYSTEM; WINDS AB On 1 March 1997 violent tornadoes caused numerous fatalities and widespread damage across portions of central and eastern Arkansas and western Tennessee. In addition, the associated thunderstorms produced very heavy rainfall and Rash flooding, with a few locations receiving up to 150 mm (6 in.) of rainfall in 3 h. The initial environment appeared favorable for strong tornadoes with unseasonably warm moist air at lower levels resulting in significant instability (convective available potential energy values between 1400 and 1800 J kg(-1)) where 0-2-km storm-relative helicities exceeded 300 m(2) s(-2) and the middle-tropospheric storm-relative flow was conducive for tornadic supercells. The most destructive tornadoes developed along a preexisting surface boundary where lower-tropospheric moisture convergence and frontogenesis were enhanced. Tornadoes and heaviest rainfall only ensue after upward motion associated with the direct circulation of an upper-tropospheric jet streak became collocated with lower-tropospheric upward forcing along the surface boundaries. From a flash flood perspective the event occurred in a hybrid mesohigh-synoptic heavy rain pattern as thunderstorms developed and moved along surface boundaries aligned nearly parallel to the mean wind. In addition, strong flow and associated moisture Bur convergence in the lower troposphere favored the formation of cells to the southwest or upstream of the initial convection with thunderstorms, including a a tornadic supercell, traversing over the same area. The available moisture and ambient instability also supported both vigorous updrafts and high precipitation rates. C1 NOAA, NWS, Storm Predict Ctr, Norman, OK 73069 USA. Natl Weather Serv, Tulsa, OK USA. RP Rogash, JA (reprint author), NOAA, NWS, Storm Predict Ctr, 1313 Halley Circle, Norman, OK 73069 USA. NR 45 TC 12 Z9 13 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 AUG PY 2000 VL 15 IS 4 BP 416 EP 431 DI 10.1175/1520-0434(2000)015<0416:MOOAVT>2.0.CO;2 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 346EX UT WOS:000088858800003 ER PT J AU Knaff, JA Zehr, RM Goldberg, MD Kidder, SQ AF Knaff, JA Zehr, RM Goldberg, MD Kidder, SQ TI An example of temperature structure differences in two cyclone systems derived from the advanced microwave sounder unit SO WEATHER AND FORECASTING LA English DT Article ID UPPER-TROPOSPHERIC TROUGH; TROPICAL CYCLONE AB The Advanced Microwave Sounding Unit (AMSU) has better horizontal resolution and vertical temperature sounding abilities than its predecessor, the Microwave Sounding Unit (MSU). Those improved capabilities are demonstrated with observations of two cyclonic weather systems located in the South Pacific Ocean on 1 March 1999. These weather systems appear quite similar in conventional infrared satellite imagery, suggesting that they are comparable in structure and intensity. However, an analysis using temperature retrievals created from the AMSU shows that their vertical thermal structure is quite different. This is just one example of an application highlighting the improved sounding capabilities available with the AMSU instrument suite. A preliminary look at what the AMSU can provide in data-void regions and a discussion of future plans to create AMSU-based products to better diagnose synoptic-scale weather systems are presented. C1 Colorado State Univ, Cooperat Inst Res Atmosphere, Ft Collins, CO 80523 USA. NOAA, NESDIS, RAMM Team, Ft Collins, CO USA. NOAA, Natl Environm Satellite Data & Informat Serv, ORA, Washington, DC 20233 USA. RP Knaff, JA (reprint author), Colorado State Univ, Cooperat Inst Res Atmosphere, Foothills Campus, Ft Collins, CO 80523 USA. RI Goldberg, Mitch/F-5589-2010; Knaff, John /F-5599-2010 OI Knaff, John /0000-0003-0427-1409 NR 24 TC 21 Z9 23 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 AUG PY 2000 VL 15 IS 4 BP 476 EP 483 DI 10.1175/1520-0434(2000)015<0476:AEOTSD>2.0.CO;2 PG 8 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 346EX UT WOS:000088858800007 ER PT J AU Collette, BB Randall, JE AF Collette, BB Randall, JE TI Ammodytoides leptus, a new species of sand lance (Teleostei : Ammodytidae) from Pitcairn Island SO PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON LA English DT Article AB Ammodytoides leptus is described from 23 specimens from Pitcairn Island. It has more lateral-line scales than any other known species of Ammodytoides or Bleekeria (119-123 vs. 88-118). It is thinner than A. pylei, A. kimurai, and A. gilli (body depth 8.6-9.5% SL vs. 9.5-11.7%). C1 Natl Museum Nat Hist, Natl Marine Fisheries Serv, Systemat Lab, Washington, DC 20560 USA. Bernice PB Bishop Museum, Honolulu, HI 96817 USA. RP Collette, BB (reprint author), Natl Museum Nat Hist, Natl Marine Fisheries Serv, Systemat Lab, Washington, DC 20560 USA. NR 9 TC 3 Z9 4 U1 0 U2 0 PU BIOL SOC WASHINGTON PI WASHINGTON PA NAT MUSEUM NAT HIST SMITHSONIAN INST, WASHINGTON, DC 20560 USA SN 0006-324X J9 P BIOL SOC WASH JI Proc. Biol. Soc. Wash. PD JUL 31 PY 2000 VL 113 IS 2 BP 397 EP 400 PG 4 WC Biology SC Life Sciences & Biomedicine - Other Topics GA 341TQ UT WOS:000088606000005 ER PT J AU Falcon, LI Vecchione, M Roper, CFE AF Falcon, LI Vecchione, M Roper, CFE TI Paralarval gonatid squids (Cephalopoda : Oegopsida) from the Mid-North Atlantic Ocean SO PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON LA English DT Article AB Ninety six gonatid cephalopod specimens (Oegopsida: Gonatidae) from the University of Amsterdam Mid-North Atlantic Plankton Expeditions were analyzed and two species were identified: Gonatus steenstrupi (Kristensen 1981) and Gonatus fabricii (Lichtenstein 1818). Gonatids were collected only in spring and summer, despite sampling in autumn and winter. This paper describes aspects of their development and reports their geographical distribution in the central North Atlantic Ocean. Chromatophore patterns were the most consistently useful characters for distinguishing between the species. Among 34 measurements, Tentacle Length (TtL) relative to Dorsal Mantle Length (ML) and number of suckers on Arms I-IV were useful for distinguishing specimens >13 mm ML. Both species develop hooks from suckers on the arms and tentacular clubs at ML >20 mm. Subtle differences were noted in the morphology of the funnel pads except in the smallest specimens. Specimens of G. steenstrupi >20 mm ML were collected at greater depths (250 to 995 m) than the smaller specimens (found at depths <200 m). Our data suggest that 20 mm ML is the point of transition between paralarvae and juveniles of G. steenstrupi, because specimens larger than 20 mm ML have well defined hooks, and a juvenile vertical distribution is established. C1 Univ Nacl Autonoma Mexico, Inst Ciencias Mar & Limnol, Mexico City 045510, DF, Mexico. Smithsonian Inst, Natl Museum Nat Hist, Res Training Program, Washington, DC 20560 USA. Natl Museum Nat Hist, Natl Systemat Lab, Natl Marine Fisheries Serv, Washington, DC 20560 USA. Smithsonian Inst, Natl Museum Nat Hist, Dept Invertebrate Zool Mollusks, Washington, DC 20560 USA. RP Falcon, LI (reprint author), Univ Nacl Autonoma Mexico, Inst Ciencias Mar & Limnol, Apdo Postal 70-305, Mexico City 045510, DF, Mexico. NR 13 TC 7 Z9 8 U1 0 U2 0 PU BIOL SOC WASHINGTON PI WASHINGTON PA NAT MUSEUM NAT HIST SMITHSONIAN INST, WASHINGTON, DC 20560 USA SN 0006-324X J9 P BIOL SOC WASH JI Proc. Biol. Soc. Wash. PD JUL 31 PY 2000 VL 113 IS 2 BP 532 EP 541 PG 10 WC Biology SC Life Sciences & Biomedicine - Other Topics GA 341TQ UT WOS:000088606000020 ER PT J AU Tikku, AA Cande, SC AF Tikku, AA Cande, SC TI On the fit of Broken Ridge and Kerguelen plateau SO EARTH AND PLANETARY SCIENCE LETTERS LA English DT Article DE sea-floor spreading; magnetic anomalies; Indian ocean; Australia; Antarctica; Tertiary; Cretaceous; Broken Ridge; Kerguelen plateau ID SEISMIC-REFLECTION DATA; EASTERN INDIAN-OCEAN; ANTARCTICA; AUSTRALIA; SOUTH; TASMANIA; HISTORY; UNCERTAINTIES; CONSTRAINTS; ANOMALIES AB We present revised finite rotation parameters for Australia and East Antarctica in the Early Tertiary incorporating new magnetic data off of Wilkes Land, Antarctica. Reconstructions based on these and recently published rotation parameters document a relatively stationary position of Broken Ridge abutted against Central Kerguelen Plateau between chron 34 (83 Ma) and chron 20 (43 Ma), prior to the commencement of seafloor spreading between the two Late Cretaceous features. These reconstructions are significant as they are the first which are consistent with geological and geophysical constraints in not producing an overlap of Broken Ridge and Kerguelen Plateau between chron 34 and chron 24 (53 Ma) and not requiring significant extension or strike-slip motion within Kerguelen Plateau. We also find that the finite rotations for chrons 20 to 34 outline the area of rough topography inferred from the satellite-derived free-air gravity for the Diamantina Zone and Labuan Basin. A consequence of these rotations is that there is considerable overlap of continental crust in the region of Tasmania, the South Tasman Rise and East Antarctica in the Late Cretaceous. Solutions to this problem may imply either post-Santonian (less than or equal to 79 Ma) extension or transform motion in the Bass Strait, or late Cretaceous or Cenozoic extension in Wilkes Land. The reconstructions also agree with prior estimates of roughly 150 km of motion between East and West Antarctica since chron 20. (C) 2000 Elsevier Science B.V. All rights reserved. C1 NOAA, Lab Satellite Alimetry, Silver Spring, MD 20910 USA. Univ Calif San Diego, Scripps Inst Oceanog, La Jolla, CA 92093 USA. RP Tikku, AA (reprint author), NOAA, Lab Satellite Alimetry, E-RA31,SSMC3,Rm 3712,1315 East West Highway, Silver Spring, MD 20910 USA. NR 63 TC 33 Z9 34 U1 0 U2 4 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 JUL 30 PY 2000 VL 180 IS 1-2 BP 117 EP 132 DI 10.1016/S0012-821X(00)00157-6 PG 16 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 337GD UT WOS:000088348300010 ER PT J AU Lupton, JE Baker, ET Massoth, GJ AF Lupton, JE Baker, ET Massoth, GJ TI Reply to Comment on "Helium, heat and the generation of hydrothermal event plumes at mid-ocean ridges", by J.E. Lupton, E.T. Baker and G.J. Massoth SO EARTH AND PLANETARY SCIENCE LETTERS LA English DT Editorial Material ID DE-FUCA RIDGE; MIDOCEAN RIDGES; BASALTS; WATER C1 NOAA, Pacific Marine Environm Lab, Hatfield Marine Sci Ctr, Newport, OR 97365 USA. NOAA, Pacific Marine Environm Lab, Seattle, WA 98195 USA. Inst Geol & Nucl Sci, Lower Hutt, New Zealand. RP Lupton, JE (reprint author), NOAA, Pacific Marine Environm Lab, Hatfield Marine Sci Ctr, Newport, OR 97365 USA. NR 14 TC 7 Z9 7 U1 1 U2 4 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 JUL 30 PY 2000 VL 180 IS 1-2 BP 219 EP 222 DI 10.1016/S0012-821X(00)00151-5 PG 4 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 337GD UT WOS:000088348300018 ER PT J AU Pursch, M Sander, LC AF Pursch, M Sander, LC TI Stationary phases for capillary electrochromatography SO JOURNAL OF CHROMATOGRAPHY A LA English DT Review DE reviews; stationary phases; CEC; electrochromatography ID PERFORMANCE LIQUID-CHROMATOGRAPHY; OCTADECYL-SULFONATED-SILICA; RIGID POLYMER MONOLITHS; REVERSED-PHASE; PACKED CAPILLARIES; SEPARATION MEDIA; BETA-CYCLODEXTRIN; MOBILE-PHASE; ENANTIOMERIC SEPARATIONS; PHARMACEUTICAL ANALYSIS AB This review summarizes the variety of stationary phases that have been employed for capillary electrochromatography (CEC) separations. Currently, about 70% of reported CEC research utilizes C-18 stationary phases designed for liquid chromatography, but an increasing number of new materials (e.g., ion-exchange phases, sol-gel approaches, organic polymer continuous beds) are under development for use in CEC. Novel aspects of these different materials are discussed including the ability to promote electroosmotic flow, phase selectivity and activity for basic solutes. In addition, new column designs (polymer continuous beds and silica-sol-gel monoliths) are described. (C) 2000 Elsevier Science B.V. All rights reserved. C1 NIST, Chem Sci & Technol Lab, Div Analyt Chem, Gaithersburg, MD 20899 USA. RP Pursch, M (reprint author), Dow Chem Co, Ind Str 1, D-77836 Rheinmuenster, Germany. NR 95 TC 60 Z9 61 U1 0 U2 8 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 JUL 28 PY 2000 VL 887 IS 1-2 BP 313 EP 326 DI 10.1016/S0021-9673(00)00457-X PG 14 WC Biochemical Research Methods; Chemistry, Analytical SC Biochemistry & Molecular Biology; Chemistry GA 336RB UT WOS:000088315800024 PM 10961323 ER PT J AU Mauzerall, DL Narita, D Akimoto, H Horowitz, L Walters, S Hauglustaine, DA Brasseur, G AF Mauzerall, DL Narita, D Akimoto, H Horowitz, L Walters, S Hauglustaine, DA Brasseur, G TI Seasonal characteristics of tropospheric ozone production and mixing ratios over East Asia: A global three-dimensional chemical transport model analysis SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID TROPICAL SOUTH-ATLANTIC; LONG-RANGE TRANSPORT; UNITED-STATES; NORTH-ATLANTIC; CARBON-MONOXIDE; ANTHROPOGENIC EMISSIONS; REACTIVE NITROGEN; FUTURE CHANGES; SURFACE OZONE; ATMOSPHERE AB We examine seasonal and geographical distributions of tropospheric ozone production and mixing ratios over East Asia with a global three-dimensional chemical transport model called Model of Ozone and Related Tracers, version 1 (MOZART 1). Net ozone production within the East Asian boundary layer exhibits three distinct seasonal cycles depending on region (north of 20 degrees N, 5-20 degrees N and south of 5 degrees N). North of 20 degrees N, net ozone production over East Asia from spring through autumn is found to have a maximum extending from 25 degrees N-40 degrees N and from central eastern China to Japan, resulting from the strong emission and transport of anthropogenic O-3 precursors. In winter, maximum O-3 production in this region occurs between 20 degrees N and 30 degrees N, This is a region of long-range transport. Over the Indochina peninsula, between 5 degrees N and 20 degrees N, net O-3 production is controlled by the seasonal cycle between wet and dry seasons and has a maximum at the end of the dry season due to emissions from biomass burning. South of 5 degrees N, in the true tropics, O-3 mixing ratios are relatively constant throughout the year and do not exhibit a seasonal cycle. A spring-summer maximum of net O-3 production is found throughout the troposphere in East Asia. We estimate an annual net O-3 production in East Asia of 117 Tg/yr, Both model results and analysis of measurements of O-3/CO correlations over East Asia and Japan show strong variability as a function of both photochemical activity and seasonal meteorology, and indicate ozone export off the coast of East Asia in spring. An upper estimate of O-3 export from East Asia to the Pacific Ocean in the mid-1980s of 3.3 Gmol/d (58 Tg/yr) is obtained. C1 Princeton Univ, Woodrow Wilson Sch Publ & Int Affairs, Princeton, NJ 08540 USA. Univ Tokyo, Adv Sci & Technol Res Ctr, Tokyo 1538904, Japan. Max Planck Inst Meteorol, D-20416 Hamburg, Germany. Univ Paris 06, CNRS, Serv Aeron, F-75230 Paris, France. Princeton Univ, Geophys Fluid Dynam Lab, Princeton, NJ 08542 USA. Natl Ctr Atmospher Res, Boulder, CO 80307 USA. RP Mauzerall, DL (reprint author), Princeton Univ, Woodrow Wilson Sch Publ & Int Affairs, Princeton, NJ 08540 USA. EM mauzerall@princeton.edu RI Mauzerall, Denise/I-5977-2013; Horowitz, Larry/D-8048-2014; Narita, Daiju/G-7125-2016 OI Mauzerall, Denise/0000-0003-3479-1798; Horowitz, Larry/0000-0002-5886-3314; Narita, Daiju/0000-0001-5695-9913 NR 73 TC 81 Z9 88 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 JUL 27 PY 2000 VL 105 IS D14 BP 17895 EP 17910 DI 10.1029/2000JD900087 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 337NT UT WOS:000088368700015 ER PT J AU Suhre, K Johnson, DW Mari, C Rosset, R Osborne, S Wood, R Bates, TS Raes, F AF Suhre, K Johnson, DW Mari, C Rosset, R Osborne, S Wood, R Bates, TS Raes, F TI A continental outbreak of air during the Second Aerosol Characterization Experiment (ACE 2): A Lagrangian experiment SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID MARINE BOUNDARY-LAYER; MODEL; PARAMETERIZATION; CLOUDINESS; TURBULENCE; SIMULATION; MESOSCALE; TRANSPORT; OXIDATION; SYSTEM AB A mesoscale meteorological model is used to simulate the continental outbreak of air that occured over North Atlantic Ocean during the Second Aerosol Characterization Experiment (ACE 2). Comparison with Meteosat 6 visible images shows that the model is able to reproduce most of the observed cloud features in the entire modeling domain, including a frontal system, orographic clouds over the Pyrenees and the Iberian Peninsula, boundary layer clouds in the ACE 2 region, and cloud-free areas in the dry air outflow off the Portuguese coast. The model reproduces correctly the temperature, humidity, wind speed and direction, cloud water content, and light precipitation events observed by the aircraft during the Lagrangian experiment, while following a tagged boundary layer air parcel over a 28-hour long period. A passive tracer, introduced in the model at the time corresponding to the balloon launch, followed the balloon track with an error in position that is smaller than 1 degrees after 24-hours with about 20% higher speed. An estimate of the boundary layer entrainment velocity is obtained, based on observed boundary layer growth rates and modeled vertical wind speed. The average entrainment velocity of 1.28 cm/s for the 28-hour Lagrangian period agrees with experimentally derived entrainment velocities. C1 Univ Toulouse 3, UMR CNRS, Lab Aerol, F-31400 Toulouse, France. NOAA, Pacific Marine Environm Lab, Seattle, WA 98115 USA. Meteorol Res Flight, Meteorol Off, Farnborough GU14 6TD, Hants, England. Commiss European Communities, Joint Res Ctr, I-21020 Ispra, Italy. RP Suhre, K (reprint author), Univ Toulouse 3, UMR CNRS, Lab Aerol, F-31400 Toulouse, France. RI Wood, Robert/A-2989-2008; Bates, Timothy/L-6080-2016; OI Wood, Robert/0000-0002-1401-3828; Suhre, Karsten/0000-0001-9638-3912 NR 26 TC 2 Z9 2 U1 0 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUL 27 PY 2000 VL 105 IS D14 BP 17911 EP 17924 DI 10.1029/2000JD900157 PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 337NT UT WOS:000088368700016 ER PT J AU Yang, FL Schlesinger, ME Rozanov, E AF Yang, FL Schlesinger, ME Rozanov, E TI Description and performance of the UIUC 24-layer stratosphere/troposphere general circulation model SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID MIDDLE ATMOSPHERE MODEL; GRAVITY-WAVE-DRAG; OFFICE UNIFIED MODEL; QBO-LIKE OSCILLATION; SOLAR-RADIATION; SATELLITE-OBSERVATIONS; 3-DIMENSIONAL MODEL; SULFATE AEROSOLS; PLANETARY-WAVES; WATER CLOUDS AB This paper describes the 24-layer stratosphere/troposphere general circulation model (24-L ST-GCM) developed by the Climate Research Group of the University of Illinois at Urbana-Champaign (UIUC). The model's dynamical and physical processes, similar to those of its ancestors, are briefly described. The newly implemented parameterizations of longwave and solar radiation, cloud-radiation interaction, subgrid-scale orographic gravity wave drag, and aerosol radiative forcing are described in more detail. Sensitivity tests using simplified one-dimensional column models and the 24-L ST-GCM are carried out to evaluate these implementations. A 15-year simulation with prescribed climatological sea-surface temperatures and sea-ice extents has been performed. To determine the model's strengths and weaknesses, the simulated results are compared with observations. The model simulates well the geographical distributions of surface-air temperature and precipitation and their seasonal variations. The simulated cloud cover and cloud radiative forcing have the observed magnitudes and latitudinal variations, except near 60 degrees S where the model underestimates the cloud cover by similar to 20-30%. It is found that the large-scale cloud distribution and the cloud-top altitude depend on the respective critical relative humidities for the onset of large-scale precipitation and penetrating convection. The model captures reasonably well the observed features of atmospheric temperature and zonal wind in both the stratosphere and troposphere in all seasons, with the exception of the northern stratospheric polar-night jet. The simulated Transformed-Eulerian-Mean residual circulation in the stratosphere has comparable magnitudes and distributions to those obtained by data assimilation and other general circulation models (GCMs). The two-cell Brewer-Dobson circulation is captured. The use of an orographic-type gravity wave drag parameterization is responsible for an abnormally warm northern polar stratosphere in winter, which is contrary to most other GCMs. C1 Univ Illinois, Dept Atmospher Sci, Climate Res Grp, Urbana, IL 61801 USA. RP Yang, FL (reprint author), Natl Ctr Environm Predict, Washington, DC USA. EM schlesin@atmos.uiuc.edu RI Yang, Fanglin/A-1948-2013; Rozanov, Eugene/A-9857-2012 OI Rozanov, Eugene/0000-0003-0479-4488 NR 91 TC 20 Z9 21 U1 1 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 JUL 27 PY 2000 VL 105 IS D14 BP 17925 EP 17954 DI 10.1029/2000JD900049 PG 30 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 337NT UT WOS:000088368700017 ER PT J AU Anderson, BT Roads, JO Chen, SC Juang, HMH AF Anderson, BT Roads, JO Chen, SC Juang, HMH TI Regional simulation of the low-level monsoon winds over the Gulf of California and southwestern United States SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID NORTH-AMERICAN MONSOON; CENTRAL ARIZONA CONVECTION; MEXICAN MONSOON; INTERANNUAL VARIABILITY; PRECIPITATION REGIME; SUMMER MONSOON; SPECTRAL MODEL; PREDICTION; FORECASTS; SYSTEM AB Using a fine-scale (10-20 km) nested regional modeling system, synoptic variations in climatological summertime low-level wind fields over the Gulf of California and the southwestern United States are described. Under appropriate synoptic conditions, strong surge events can develop. These are characterized by low-level southerly flow over the entire Gulf of California with southerly winds extending into Arizona, California, and southern Nevada. Vertically, these southerly winds are present through the bottom 1-2 km of the atmosphere. Southerly flow is persistent throughout the day with some local diurnal cycling over the foothills of the Sierra Madre Occidental and northwestern Mexico. Under nonsurge conditions the simulated low-level winds have a significantly different geographic structure. Nighttime southerly flow is limited to the northeastern Gulf and small portions of southwestern Arizona. Flow over the central and southern Gulf is northerly with weak, variable winds over the foothills of the Sierra Madre Occidental. During the day, southerly winds are present over the central and northern Gulf of California, extending into southwestern Arizona; however, this southerly wind pattern does not support continuous flow from the mouth of the Gulf into northwestern Mexico. Instead, there is a westerly component associated with predominantly upslope flow over the foothills of the Sierra Madre Occidental and the Sonora Desert. C1 Univ Hawaii Manoa, Honolulu, HI 96822 USA. Univ Calif San Diego, Scripps Inst Oceanog, La Jolla, CA 92093 USA. NCEP, Climate Predict Ctr, Washington, DC 20233 USA. RP Anderson, BT (reprint author), Univ Hawaii Manoa, 2525 Correa Rd,HIG 431, Honolulu, HI 96822 USA. EM anderson@soest.hawaii.edu NR 30 TC 47 Z9 48 U1 1 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUL 27 PY 2000 VL 105 IS D14 BP 17955 EP 17969 DI 10.1029/2000JD900161 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 337NT UT WOS:000088368700018 ER PT J AU Burkholder, JB AF Burkholder, JB TI NO3 yield in the O(P-3)+BrONO2 reaction SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article AB The NO3 product yield in the reaction O(P-3) + BrONO2 was measured to be >0.85 at 298 K. Yield measurements were made using the technique of laser-pulsed photolysis with long-path transient absorption detection of NO3. O(P-3) atoms were produced in the presence of BrONO2 by the 248-nm photolysis of O-3 in a N-2 bath gas. The photolysis laser fluence was calibrated using N2O5 as an actinometer. C1 NOAA, Aeron Lab, Boulder, CO 80303 USA. RP Burkholder, JB (reprint author), NOAA, Aeron Lab, R-AL2,325 Broadway, Boulder, CO 80303 USA. RI Burkholder, James/H-4914-2013 NR 13 TC 4 Z9 5 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD JUL 27 PY 2000 VL 104 IS 29 BP 6733 EP 6737 DI 10.1021/jp9942926 PG 5 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 339QW UT WOS:000088490300008 ER PT J AU Burkholder, JB Ravishankara, AR AF Burkholder, JB Ravishankara, AR TI Rate coefficient for the reaction: O+NO2+M -> NO3+M SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID QUANTUM YIELDS; NO3; PHOTODISSOCIATION; ABSORPTION; N2O5 AB The rate coefficient for the reaction O(P-3) + NO2 + M --> NO3 + M (M = N-2), k(1b), was measured over the pressure range 20-800 Torr (N-2) between 220 and 296 K. Pulsed laser photolysis of NO2 at 352 nm was used to produce O atoms and transient long-path diode laser absorption at 662 nm was used to detect NO3 produced in the reaction. The pressure and temperature dependence of the measured rate coefficient is reproduced by the expression k(1b)(T,M) = [k(0)(T)[M]/(1 + (k(0)(T)[M]/k(infinity)(T))]F-c(x), where x = {1 + [log(k(0)(T)[M]/k(infinity)(T))](2)}(-1) and k(0)(T) = k(0)(300) (T/300)(-n), k(infinity)(T) = k(infinity)(300) (T/300)(-m) with k(0) = 3 x 10(-31) cm(6) molecule(-2) s(-1), n = 1.75, k(infinity) = 3.75 x 10(-11) cm(3) molecule(-1) s(-1). m = 0, and F-c = 0.6. This fit does not yield unique values for k(infinity) or k(0) but are presented here merely to obtain k(1b)(T,M) for atmospheric modeling purposes. The reported values are significantly larger than the current recommendation for stratospheric modeling. Our larger values do not significantly increase the role of the title reaction in the Earth's atmosphere in terms of either ozone loss rate or conversion of reactive nitrogen oxides to less reactive forms such as HNO3. C1 NOAA, Aeron Lab, Boulder, CO 80303 USA. Univ Colorado, Dept Chem & Biochem, Boulder, CO 80309 USA. RP Burkholder, JB (reprint author), NOAA, Aeron Lab, 325 Broadway, Boulder, CO 80303 USA. RI Burkholder, James/H-4914-2013; Ravishankara, Akkihebbal/A-2914-2011 NR 12 TC 8 Z9 8 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 JUL 27 PY 2000 VL 104 IS 29 BP 6752 EP 6757 DI 10.1021/jp000169z PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 339QW UT WOS:000088490300010 ER PT J AU Magid, LJ Han, Z Li, Z Butler, PD AF Magid, LJ Han, Z Li, Z Butler, PD TI Tuning the contour lengths and persistence lengths of cationic micelles: The pole of electrostatics and specific ion binding SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Review ID ANGLE NEUTRON-SCATTERING; POLYMER-LIKE MICELLES; SODIUM DODECYL-SULFATE; LIGHT-SCATTERING; CETYLTRIMETHYLAMMONIUM BROMIDE; RODLIKE MICELLES; AQUEOUS-MEDIA; VISCOELASTIC PROPERTIES; SEMIFLEXIBLE POLYMERS; CYLINDRICAL MICELLES AB Small-angle scattering has been used to obtain detailed information on micellar contour lengths and persistence lengths, a measure of micellar flexibility, for mixed micelles of cetyltrimethylammonium 2,6-dichlorobenzoate and cetyltrimethylammonium chloride in water as a function of surfactant and salt concentrations and the relative amounts of the two counterions (the counterion inventory) at the micellar surface. Increasing amounts at the surface of the penetrating counterion of the pair, 2,6-dichlorobenzoate, lowers the 1D bending modulus of the micelles, making them more flexible. Micellar contour lengths exhibit a maximum with increasing amounts of a,2,6-dichlorobenzoate at the micellar surface. This is understood in terms of decreases in the micellar end-cap energies, E-c, at high concentrations of penetrating counterion. By decreasing the effective micellar surface charge density, penetrating counterions also cause decreased contributions from electrostatic repulsion, E-e, which retard micellar growth. At low ionic strengths, this results in more extensive micellar growth upon addition of sodium 2,6-dichlorobenzoate rather than NaCl. C1 Univ Tennessee, Dept Chem, Knoxville, TN 37996 USA. NIST, NCNR, Gaithersburg, MD 20899 USA. RP Magid, LJ (reprint author), Univ Tennessee, Dept Chem, Knoxville, TN 37996 USA. RI Butler, Paul/D-7368-2011 NR 61 TC 34 Z9 34 U1 0 U2 9 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 JUL 27 PY 2000 VL 104 IS 29 BP 6717 EP 6727 DI 10.1021/jp994477c PG 11 WC Chemistry, Physical SC Chemistry GA 339QY UT WOS:000088490500006 ER PT J AU Pursch, M Vanderhart, DL Sander, LC Gu, XH Nguyen, T Wise, SA Gajewski, DA AF Pursch, M Vanderhart, DL Sander, LC Gu, XH Nguyen, T Wise, SA Gajewski, DA TI C-30 self-assembled monolayers on silica, titania, and zirconia: HPLC performance, atomic force microscopy, ellipsometry, and NMR studies of molecular dynamics and uniformity of coverage SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID C-13 CHEMICAL-SHIFTS; PHASE LIQUID-CHROMATOGRAPHY; BONDED STATIONARY PHASES; SOLID-STATE NMR; CAROTENOID ISOMERS; SEPARATION; SURFACE; IDENTIFICATION; SPECTROSCOPY; TEMPERATURE AB C-30 self-assembled monolayers (SAMs) have been prepared on zirconia, titania, and two different silica gels by reacting C-30 trichlorosilane with the humidified surfaces. C-13 solid-state NMR spectroscopy indicated higher alkyl chain order on titania and zirconia materials than on the silica C-30 phases. Order is inferred from the relative intensity of the main methylene carbon resonance assigned to an all-trans conformation. Carbon longitudinal relaxation time (T-1(C)) data reveal that these ordered alkyl chains still have large-amplitude motions on submicrosecond time scales at ambient temperature. Since fast diffusional rotation about the chain axis is compatible with an all-trans conformation, T-1(C), carbon chemical shift, and proton line width data for the alkane rotator phase (C-19) and the C-30 phases were compared. Proton spin diffusion experiments were also conducted using an initial polarization gradient based on mobility differences. These;experiments indicated both a higher mobility for the free end of the immobilized chains and heterogeneity in the density of coverage on at least the 20-nm distance scale. The methyl carbon line shape is also discussed in detail since its chemical shift conveys information about both mobility and interactions with an air interface in a dry sample. Atomic force microscopy and contact angle studies indicated a greater surface roughness for C-30 SAMs compared to C-18 SAMs prepared on silicon. Ellipsometry revealed film thicknesses of 2.82 nm for the C-18 SAM and 4.05 nm for the C-30 SAM. High shape selectivity was found in correspondent liquid chromatographic (LC) separations of polycyclic aromatic hydrocarbons, carotenoids, and tocopherols. The LC data confirm the highly organized alkyl chain arrangement on zirconia and titania, which provide an alternative to the silica-based reversed phases. C1 Natl Inst Stand & Technol, Analyt Chem Div, Chem Sci & Technol Lab, Gaithersburg, MD 20899 USA. Natl Inst Stand & Technol, Polymers Div, Mat Sci & Engn Lab, Gaithersburg, MD 20899 USA. Natl Inst Stand & Technol, Bldg Mat Div, Bldg & Fire Res Lab, Gaithersburg, MD 20899 USA. Natl Inst Stand & Technol, Elect & Elect Engn Lab, Div Semicond Elect, Gaithersburg, MD 20899 USA. RP Pursch, M (reprint author), Dow Deutschland Inc, Ind Str 1, D-77836 Rheinmuenster, Germany. NR 58 TC 49 Z9 49 U1 1 U2 8 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 JUL 26 PY 2000 VL 122 IS 29 BP 6997 EP 7011 DI 10.1021/ja993705d PG 15 WC Chemistry, Multidisciplinary SC Chemistry GA 340FP UT WOS:000088522700023 ER PT J AU Gajewski, DA Guyer, JE Pellegrino, JG AF Gajewski, DA Guyer, JE Pellegrino, JG TI Real-time measurements of the pseudodielectric function of low-temperature-grown GaAs SO APPLIED PHYSICS LETTERS LA English DT Article ID MOLECULAR-BEAM EPITAXY; DIFFUSE-REFLECTANCE SPECTROSCOPY; OPTICAL-PROPERTIES; IN-SITU; ELLIPSOMETRY; LAYERS; 200-DEGREES-C; PARAMETERS; THICKNESS; DEFECTS AB We present real-time in situ spectroscopic ellipsometry (SE) measurements of the pseudodielectric function of low-temperature-grown GaAs as a function of growth temperature T-g, As-2:Ga flux ratio R, and thickness. We show that the interband critical point E-1 amplitude and sharpness decrease monotonically with decreasing T-g and/or increasing R for layers thinner than the critical epitaxial thickness h(epi). We used in situ SE to reveal distinct signatures of the onset of polycrystalline or amorphous growth above h(epi), which depends strongly on T-g. We revealed these systematic trends using in situ SE in conjunction with diffuse reflectance spectroscopy for active feedback temperature control. (C) 2000 American Institute of Physics. [S0003-6951(00)02028-3]. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Gajewski, DA (reprint author), US Dept Commerce, Div Semicond Elect, Elect & Elect Engn Lab, Technol Adm, Washington, DC 20230 USA. RI Guyer, Jonathan/M-5165-2016 OI Guyer, Jonathan/0000-0002-1407-6589 NR 23 TC 1 Z9 1 U1 1 U2 1 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD JUL 24 PY 2000 VL 77 IS 4 BP 540 EP 542 DI 10.1063/1.127037 PG 3 WC Physics, Applied SC Physics GA 335CX UT WOS:000088225400027 ER PT J AU Glotzer, SC Jans, N Poole, PH AF Glotzer, SC Jans, N Poole, PH TI The potential energy landscape of the +/- J Ising spin glass SO JOURNAL OF PHYSICS-CONDENSED MATTER LA English DT Article; Proceedings Paper CT Workshop on Unifying Concepts in Glass Physics CY SEP 15-18, 1999 CL ABDUS SALAM INT CTR THEORET PHYS, TRIESTE, ITALY SP Abdus Salam Int Ctr Theoret Phys, Natl Inst Stand & Technol, Ctr Theoret & Computat Mat Sci HO ABDUS SALAM INT CTR THEORET PHYS ID LENNARD-JONES LIQUID; PHASE-TRANSITIONS; SPATIAL CORRELATIONS; CRITICAL-TEMPERATURE; SUPERCOOLED LIQUIDS; CRITICAL-BEHAVIOR; DYNAMICS; MODEL; OPTIMIZATION; MOTION AB We calculate 'inherent structures' (configurations corresponding to local potential energy minima) in the +/- J Ising spin glass over a wide range of temperature T in two and three dimensions. We find that the T-dependence of the average value of the inherent-structure energy E is strikingly similar to that shown recently for a glass-forming liquids. E decreases with T only weakly at high T, bur begins to decrease much more rapidly as the spin-glass transition temperature T(sg) is approached. As in the liquid, we find that the rapid decrease of E with decreasing T occurs in the regime of T in which the relaxation of the spin autocorrelation function becomes increasingly non-exponential. In addition, we show that the inherent structures of the spin glass can be used to identify clusters of strongly correlated 'frozen' spins, and that an incipient percolating cluster of these spins appears (within numerical error) at T = T(sg). C1 NIST, Div Polymers, Gaithersburg, MD 20899 USA. NIST, Ctr Theoret & Computat Mat Sci, Gaithersburg, MD 20899 USA. St Francis Xavier Univ, Dept Phys, Antigonish, NS B2G 2W5, Canada. Univ Western Ontario, Dept Appl Math, London, ON N6A 5B7, Canada. RP Glotzer, SC (reprint author), NIST, Div Polymers, Gaithersburg, MD 20899 USA. RI Poole, Peter/C-7943-2009 OI Poole, Peter/0000-0001-5985-0585 NR 51 TC 7 Z9 7 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0953-8984 J9 J PHYS-CONDENS MAT JI J. Phys.-Condes. Matter PD JUL 24 PY 2000 VL 12 IS 29 BP 6675 EP 6682 DI 10.1088/0953-8984/12/29/337 PG 8 WC Physics, Condensed Matter SC Physics GA 344FE UT WOS:000088747900038 ER PT J AU Franz, S Glotzer, SC Sastry, S AF Franz, S Glotzer, SC Sastry, S TI Special issue containing articles from the ICTP-NIS Conference on 'Unifying concepts in glass physics', - 15-18 September 1999, Trieste, Italy - Preface SO JOURNAL OF PHYSICS-CONDENSED MATTER LA English DT Editorial Material C1 ICTP, Trieste, Italy. NIST, Gaithersburg, MD 20899 USA. JNCASR, Bangalore, Karnataka, India. RP Franz, S (reprint author), ICTP, Trieste, Italy. RI franz, silvio/G-6963-2012 NR 0 TC 3 Z9 3 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0953-8984 J9 J PHYS-CONDENS MAT JI J. Phys.-Condes. Matter PD JUL 24 PY 2000 VL 12 IS 29 BP U3 EP U3 PG 1 WC Physics, Condensed Matter SC Physics GA 344FE UT WOS:000088747900001 ER PT J AU Roberts, JL Claussen, NR Cornish, SL Wieman, CE AF Roberts, JL Claussen, NR Cornish, SL Wieman, CE TI Magnetic field dependence of ultracold inelastic collisions near a Feshbach resonance SO PHYSICAL REVIEW LETTERS LA English DT Article ID BOSE-EINSTEIN CONDENSATE; MAGNETOOPTICAL TRAP; ATOMS; RECOMBINATION; SCATTERING; DECAY AB Inelastic collision rates for ultracold Rb-85 atoms in the F = 2, m(f) = -2 state have been measured as a function of magnetic field. At 250 gauss (G), the two- and three-body loss rates were measured to be K-2 = (1.87 +/- 0.95 +/- 0.19) x 10(-14) cm(3)/s and K-3 = (4.24(-0.29)(+0.70) +/- 0.85) x 10(-25) cm(6)/s, respectively. As the magnetic field is decreased from 250 G towards a Feshbach resonance at 155 G, the inelastic rates decrease to a minimum and then increase dramatically, peaking at the Feshbach resonance. Both two- and three-body losses are important, and individual contributions have been compared with theory. C1 Natl Inst Stand & Technol, JILA, Boulder, CO 80309 USA. Univ Colorado, Boulder, CO 80309 USA. Univ Colorado, Dept Phys, Boulder, CO 80309 USA. RP Roberts, JL (reprint author), Natl Inst Stand & Technol, JILA, Boulder, CO 80309 USA. RI Cornish, Simon/K-4966-2012 OI Cornish, Simon/0000-0003-1407-4126 NR 20 TC 135 Z9 135 U1 1 U2 5 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD JUL 24 PY 2000 VL 85 IS 4 BP 728 EP 731 DI 10.1103/PhysRevLett.85.728 PG 4 WC Physics, Multidisciplinary SC Physics GA 336PL UT WOS:000088311800012 ER PT J AU Xu, GY Aeppli, G Bisher, ME Broholm, C DiTusa, JF Frost, CD Ito, T Oka, K Paul, RL Takagi, H Treacy, MMJ AF Xu, GY Aeppli, G Bisher, ME Broholm, C DiTusa, JF Frost, CD Ito, T Oka, K Paul, RL Takagi, H Treacy, MMJ TI Holes in a quantum spin liquid SO SCIENCE LA English DT Article ID TRANSITION-METAL OXIDE; HALDANE-GAP; HEISENBERG CHAIN; FLUCTUATIONS; DYNAMICS; Y2BANIO5; ANTIFERROMAGNETS; SYSTEMS; STATES AB Magnetic neutron scattering provides evidence for nucleation of antiferromagnetic droplets around impurities in a doped nickel oxide-based quantum magnet. The undoped parent compound contains a spin Liquid with a cooperative singlet ground state and a gap in the magnetic excitation spectrum. Calcium doping creates excitations below the gap with an incommensurate structure factor. We show that weakly interacting antiferromagnetic droplets with a central phase shift of pi and a size controlled by the correlation Length of the quantum Liquid can account for the data. The experiment provides a quantitative impression of the magnetic polarization cloud associated with holes in a doped transition metal oxide. C1 Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. NEC Res Inst, Princeton, NJ 08540 USA. Natl Inst Stand & Technol, Ctr Neutron Res, Gaithersburg, MD 20899 USA. Louisiana State Univ, Dept Phys & Astron, Baton Rouge, LA 70803 USA. Rutherford Appleton Lab, ISIS Facil, Didcot OX11 0QX, Oxon, England. Electrotech Lab, Tsukuba, Ibaraki 305, Japan. Univ Tokyo, Grad Sch Frontier Sci, Dept Adv Mat Sci, Tokyo 1138656, Japan. RP Broholm, C (reprint author), Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. RI Takagi, Hidenori/B-2935-2010; Broholm, Collin/E-8228-2011; Xu, Guangyong/A-8707-2010 OI Broholm, Collin/0000-0002-1569-9892; Xu, Guangyong/0000-0003-1441-8275 NR 25 TC 55 Z9 56 U1 1 U2 14 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD JUL 21 PY 2000 VL 289 IS 5478 BP 419 EP 422 DI 10.1126/science.289.5478.419 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 336ME UT WOS:000088305500037 ER PT J AU Ake, TB Dupree, AK Young, PR Linsky, JL Malina, RF Griffiths, NW Siegmund, OHW Woodgate, BE AF Ake, TB Dupree, AK Young, PR Linsky, JL Malina, RF Griffiths, NW Siegmund, OHW Woodgate, BE TI Far Ultraviolet Spectroscopic Explorer observations of the active cool star AB Doradus SO ASTROPHYSICAL JOURNAL LA English DT Article DE stars : chromospheres; stars : flare; stars : individual (AB Doradus); stars : pre-main-sequence; ultraviolet : stars ID X-RAY OBSERVATIONS AB Far-ultraviolet spectra were obtained of the active cool star AB Doradus (HD 36705) during the calibration and checkout period of the Fur Ultraviolet Spectroscopic Explorer (FUSE) satellite. Observations in this early phase of the mission were taken at a resolving power of 12,000-15,000 (similar to 20-25 km s(-1)) and covered the spectral range 905-1187 Angstrom. The integrated spectrum exhibits strong, rotationally broadened stellar emission from C III (lambda lambda 977, 1175) and O VI (lambda lambda 1032, 1037) and many weaker lines. Strong emission lines of C III and O VI exhibit broad wings. The C III lambda 977 profile shows blueshifted absorption at similar to 30 km s(-1), and C II lambda 1036 absorption appears superposed on emission in the wing of O vr lambda 1037. Rotational modulation of C III and O VI is present, in harmony with its photometric variability. Flares were detected in the brightest lines, and subexposures were analyzed to examine flux and profile variations. Downflows that extend to 600 km s(-1) during a flare are found in the O VI profiles. These early observations demonstrate that FUSE will be an exceptional instrument for studying chromospheres in cool stars. C1 Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. Comp Sci Corp, Lanham Seabrook, MD USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. Natl Inst Stand & Technol, Gaithersburg, MD USA. Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. RP Ake, TB (reprint author), Johns Hopkins Univ, Dept Phys & Astron, 3400 N Charles St, Baltimore, MD 21218 USA. RI Woodgate, Bruce/D-2970-2012 NR 14 TC 24 Z9 24 U1 0 U2 0 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 JUL 20 PY 2000 VL 538 IS 1 BP L87 EP L90 DI 10.1086/312796 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 343ML UT WOS:000088706100020 ER PT J AU Jenkins, EB Oegerle, WR Gry, C Vallerga, J Sembach, KR Shelton, RL Ferlet, R Vidal-Madjar, A York, DG Linsky, JL Roth, KC Dupree, AK Edelstein, J AF Jenkins, EB Oegerle, WR Gry, C Vallerga, J Sembach, KR Shelton, RL Ferlet, R Vidal-Madjar, A York, DG Linsky, JL Roth, KC Dupree, AK Edelstein, J TI The ionization of the local interstellar medium as revealed by Far Ultraviolet Spectroscopic Explorer observations of N, O, and Ar toward white dwarf stars SO ASTROPHYSICAL JOURNAL LA English DT Article DE ISM : abundances; ISM : clouds; ultraviolet : ISM; white dwarfs ID SEQUENCE-B-STARS; CHEMICAL EVOLUTION; ELEMENT ABUNDANCES; SOLAR NEIGHBORHOOD; ORION ASSOCIATION; STELLAR SPECTRA; CHARGE-TRANSFER; OXYGEN; GAS; HELIOSPHERE AB Far Ultraviolet Spectroscopic Explorer spectra of the white dwarf stars G191-B2B, GD 394, WD 2211-495, and WD 2331-475 cover the absorption features out of the ground electronic states of N I, N II, N III, O I, and Ar I in the far-ultraviolet, providing new insights on the origin of the partial ionization of the local interstellar medium (LISM) and, for the case of G191-B2B, the interstellar cloud that immediately surrounds the solar system. Toward these targets the interstellar abundances of Ar I, and sometimes N I, are significantly below their cosmic abundances relative to H I. In the diffuse interstellar medium, these elements are not likely to be depleted onto dust grains. Generally, we expect that Ar should be more strongly ionized than H (and also O and N, whose ionizations are coupled to that of H via charge-exchange reactions) because the cross section for the photoionization of Ar I is very high. Our finding that Ar I/H I is low may help to explain the surprisingly high ionization of He in the LISM found by other investigators. Our result favors the interpretation that the ionization of the local medium is maintained by a strong extreme-ultraviolet flux from nearby stars and hot gases, rather than an incomplete recovery from a past, more highly ionized condition. C1 Princeton Univ Observ, Princeton, NJ 08544 USA. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. ISO Data Ctr, ESA Astrophys Div, Madrid 28080, Spain. Astron Spatiale Lab, F-13376 Marseille 12, France. Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. Inst Astrophys, F-7504 Paris, France. Univ Chicago, Dept Astron & Astrophys, Chicago, IL 60637 USA. Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. Natl Inst Stand & Technol, Boulder, CO 80309 USA. Smithsonian Astrophys Observ, Cambridge, MA 02138 USA. RP Jenkins, EB (reprint author), Princeton Univ Observ, Peyton Hall, Princeton, NJ 08544 USA. RI Oegerle, William/C-9070-2012; Jenkins, Edward/P-5684-2014 OI Jenkins, Edward/0000-0003-1892-4423 NR 36 TC 90 Z9 90 U1 0 U2 1 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 JUL 20 PY 2000 VL 538 IS 1 BP L81 EP L85 DI 10.1086/312786 PN 2 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 343ML UT WOS:000088706100019 ER PT J AU Moos, HW Cash, WC Cowie, LL Davidsen, AF Dupree, AK Feldman, PD Friedman, SD Green, JC Green, RF Gry, C Hutchings, JB Jenkins, EB Linsky, JL Malina, RF Michalitsianos, AG Savage, BD Shull, JM Siegmund, OHW Snow, TP Sonneborn, G Vidal-Madjar, A Willis, AJ Woodgate, BE York, DG Ake, TB Andersson, BG Andrews, JP Barkhouser, RH Bianchi, L Blair, WP Brownsberger, KR Cha, AN Chayer, P Conard, SJ Fullerton, AW Gaines, GA Grange, R Gummin, MA Hebrard, G Kriss, GA Kruk, JW Mark, D McCarthy, DK Morbey, CL Murowinski, R Murphy, EM Oegerle, WR Ohl, RG Oliveira, C Osterman, SN Sahnow, DJ Saisse, M Sembach, KR Weaver, HA Welsh, BY Wilkinson, E Zheng, W AF Moos, HW Cash, WC Cowie, LL Davidsen, AF Dupree, AK Feldman, PD Friedman, SD Green, JC Green, RF Gry, C Hutchings, JB Jenkins, EB Linsky, JL Malina, RF Michalitsianos, AG Savage, BD Shull, JM Siegmund, OHW Snow, TP Sonneborn, G Vidal-Madjar, A Willis, AJ Woodgate, BE York, DG Ake, TB Andersson, BG Andrews, JP Barkhouser, RH Bianchi, L Blair, WP Brownsberger, KR Cha, AN Chayer, P Conard, SJ Fullerton, AW Gaines, GA Grange, R Gummin, MA Hebrard, G Kriss, GA Kruk, JW Mark, D McCarthy, DK Morbey, CL Murowinski, R Murphy, EM Oegerle, WR Ohl, RG Oliveira, C Osterman, SN Sahnow, DJ Saisse, M Sembach, KR Weaver, HA Welsh, BY Wilkinson, E Zheng, W CA FUSE Sci Team FUSE Instrument Team FUSE Sci Operations Team TI Overview of the Far Ultraviolet Spectroscopic Explorer Mission SO ASTROPHYSICAL JOURNAL LA English DT Article DE instrumentation : spectrographs; space vehicles; telescopes; ultraviolet : general ID PERFORMANCE; FUSE; TELESCOPE; DESIGN; SPECTROGRAPH; CALIBRATION; VOYAGER; GAS AB The Far Ultraviolet Spectroscopic Explorer satellite observes light in the far-ultraviolet spectral region, 905-1187 Angstrom, with a high spectral resolution. The instrument consists of four co-aligned prime-focus telescopes and Rowland spectrographs with microchannel plate detectors. Two of the telescope channels use Al :LiF coatings for optimum reflectivity between approximately 1000 and 1187 Angstrom, and the other two channels use SiC coatings for optimized throughput between 905 and 1105 Angstrom. The gratings are holographically ruled to correct largely for astigmatism and to minimize scattered light. The microchannel plate detectors have KBr photocathodes and use photon counting to achieve good quantum efficiency with low background signal. The sensitivity is sufficient to examine reddened lines of sight within the Milky Way and also sufficient to use as active galactic nuclei and QSOs for absorption-line studies of both Milky Way and extragalactic gas clouds. This spectral region contains a number of key scientific diagnostics, including O VI, H I, D I, and the strong electronic transitions of H(2) and HD. C1 Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. Univ Colorado, Dept Astrophys & Planetary Sci, Ctr Astrophys & Space Astron, Boulder, CO 80309 USA. Univ Hawaii, Inst Astron, Honolulu, HI 96822 USA. Ctr Astrophys, Cambridge, MA 02138 USA. Natl Opt Astron Observ, Tucson, AZ 85726 USA. Astron Spatiale Lab, F-13376 Marseille 12, France. ISO Data Ctr, ESA Astrophys Div, Madrid 28080, Spain. Natl Res Council Canada, Herzberg Inst Astrophys, Victoria, BC V8X 4M6, Canada. Princeton Univ Observ, Princeton, NJ 08544 USA. Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. Natl Inst Stand & Technol, Boulder, CO 80309 USA. Univ Calif Berkeley, Ctr EUV Astrophys, Berkeley, CA 94720 USA. NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. Univ Wisconsin, Dept Astron, Madison, WI 53706 USA. Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. Inst Astrophys, CNRS, F-75014 Paris, France. UCL, Dept Phys & Astron, London WC1E 6BT, England. Univ Chicago, Dept Astron & Astrophys, Chicago, IL 60637 USA. Comp Sci Corp, Lanham, MD 20706 USA. Osserv Astron Torino, I-10025 Pino Torinese, TO, Italy. Univ Victoria, Dept Phys & Astron, Victoria, BC V8W 3P6, Canada. Space Telescope Sci Inst, Baltimore, MD 21218 USA. Swales Associates, Beltsville, MD 20705 USA. RP Moos, HW (reprint author), Johns Hopkins Univ, Dept Phys & Astron, 3400 N Charles St, Baltimore, MD 21218 USA. RI Oegerle, William/C-9070-2012; Sonneborn, George/D-5255-2012; Woodgate, Bruce/D-2970-2012; Kruk, Jeffrey/G-4047-2012; Jenkins, Edward/P-5684-2014; Weaver, Harold/D-9188-2016 OI Jenkins, Edward/0000-0003-1892-4423; NR 46 TC 383 Z9 384 U1 5 U2 9 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD JUL 20 PY 2000 VL 538 IS 1 BP L1 EP L6 DI 10.1086/312795 PN 2 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 343ML UT WOS:000088706100001 ER PT J AU Murphy, EM Sembach, KR Gibson, BK Shull, JM Savage, BD Roth, KC Moos, HW Green, JC York, DG Wakker, BP AF Murphy, EM Sembach, KR Gibson, BK Shull, JM Savage, BD Roth, KC Moos, HW Green, JC York, DG Wakker, BP TI Far Ultraviolet Spectroscopic Explorer spectroscopy of high-velocity cloud complex C SO ASTROPHYSICAL JOURNAL LA English DT Article DE Galaxy : abundances; Galaxy : general; ISM : abundances ID INTERSTELLAR-MEDIUM; MOLECULAR GAS; ABSORPTION; HYDROGEN; SEARCH AB We present Far Ultraviolet Spectscopic Explorer (FUSE) observations of the sight line toward the Seyfert 1 galaxy Markarian 876, which passes through high-velocity cloud (HVC) complex C. This sight line demonstrates the ability of FUSE to measure ionic absorption lines in Galactic HVCs. High-velocity absorption is clearly seen in both members of the O VI doublet. This is the first detection of O VI in a neutral hydrogen HVC, One component of HVC complex C is resolved in multiple Fe II lines from which we derive N(Fe II)/N(H I) = 0.48 (Fe/H).. This value of N(Fe II)IN(H I) implies that the metallicity of complex C along this sight line may be higher than that along the Mrk 290 sight line (0.1 solar) found by Wakker et al. On the other hand, if the metallicity of complex C is also 0.1 solar along this line of sight, the observed value of N(Fe II)IN(H I) suggests: there may be a significant amount of He along the line of sight. In any case, little, if any, iron can be depleted into dust grains if the intrinsic metallicity of complex C is subsolar. Absorption from complex C is also seen in C II, N I, and N II, and upper limits based on nondetections can be determined for Ar r, P II, and Fe In. Although molecular hydrogen in the Milky Way is obvious in the FUSE data, no H, absorption is seen in the HVC to a limit N(H-2)< 2.0 x 10(14) cm(-2). Future FUSE observations of extragalactic objects behind Galactic HVCs will allow us to better constrain models of HVC origins. C1 Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. Univ Colorado, Dept Astrophys & Planetary Sci, Ctr Astrophys & Space Astron, Boulder, CO 80309 USA. Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. Natl Inst Stand & Technol, Boulder, CO 80309 USA. Univ Wisconsin, Dept Astron, Madison, WI 53706 USA. Univ Chicago, Dept Astron & Astrophys, Chicago, IL 60637 USA. RP Murphy, EM (reprint author), Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. RI Gibson, Brad/M-3592-2015 OI Gibson, Brad/0000-0003-4446-3130 NR 20 TC 43 Z9 44 U1 0 U2 1 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 JUL 20 PY 2000 VL 538 IS 1 BP L35 EP L38 DI 10.1086/312801 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 343ML UT WOS:000088706100008 ER PT J AU Shull, JM Tumlinson, J Jenkins, EB Moos, HW Rachford, BL Savage, BD Sembach, KR Snow, TP Sonneborn, G York, DG Blair, WP Green, JC Friedman, SD Sahnow, DJ AF Shull, JM Tumlinson, J Jenkins, EB Moos, HW Rachford, BL Savage, BD Sembach, KR Snow, TP Sonneborn, G York, DG Blair, WP Green, JC Friedman, SD Sahnow, DJ TI Far Ultraviolet Spectroscopic Explorer observations of diffuse interstellar molecular hydrogen SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : individual (Large Magellanic Cloud, Small Magellanic Cloud); ISM : clouds; ISM : molecules; ultraviolet : ISM ID GAS AB We describe a moderate-resolution Far Ultraviolet Spectroscopic Explorer (FUSE) minisurvey of H-2 in the Milky Way and Magellanic Clouds using four hot stars and four active galactic nuclei as background sources. FUSE spectra of nearly every stellar and extragalactic source exhibit numerous absorption lines from the H-2 Lyman and Werner bands between 912 and 1120 Angstrom. One extragalactic sight line (PKS 2155-304) with low N(H I) shows no detectable H-2 and could be the "Lockman Hole of molecular gas," of importance for QSO absorption-line studies. We measure H-2 column densities in low rotational states (J = O and 1) to derive rotational and/or kinetic temperatures of diffuse interstellar gas. The higher J abundances can constrain models of the UV radiation fields and gas densities. In three optically thick clouds toward extragalactic sources, we find n(H) approximate to 30-50 cm(-3) and cloud thicknesses similar to 2-3 pc. The rotational temperatures for H-2 at high Galactic latitude, (T-01) = 107 +/- 17 K (seven sight lines) and 120 +/- 13 K (three optically thick clouds), are higher than those in the Copernicus sample composed primarily of targets in the disk. We find no evidence for great differences in the abundance or state of excitation of H-2 between sight lines in the Galaxy and those in the SMC and LMC. In the future, we will probe the distribution and physical parameters of diffuse molecular gas in the disk and halo and in the lower metallicity environs of the LMC and SMC. C1 Univ Colorado, Ctr Astrophys & Space Astron, Boulder, CO 80309 USA. Univ Colorado, Dept Astrophys & Planetary Sci, Boulder, CO 80309 USA. Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. Natl Inst Stand & Technol, Gaithersburg, MD USA. Princeton Univ, Dept Astrophys Sci, Princeton, NJ 08544 USA. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. Univ Wisconsin, Dept Astron, Madison, WI 53706 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Chicago, Dept Astron & Astrophys, Chicago, IL 60637 USA. RP Shull, JM (reprint author), Univ Colorado, Ctr Astrophys & Space Astron, Campus Box 391, Boulder, CO 80309 USA. RI Jenkins, Edward/P-5684-2014 OI Jenkins, Edward/0000-0003-1892-4423 NR 21 TC 82 Z9 82 U1 0 U2 1 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 JUL 20 PY 2000 VL 538 IS 1 BP L73 EP L76 DI 10.1086/312782 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 343ML UT WOS:000088706100017 ER PT J AU Shull, JM Giroux, ML Penton, SV Tumlinson, J Stocke, JT Jenkins, EB Moos, HW Oegerle, WR Savage, BD Sembach, KR York, DG Green, JC Woodgate, BE AF Shull, JM Giroux, ML Penton, SV Tumlinson, J Stocke, JT Jenkins, EB Moos, HW Oegerle, WR Savage, BD Sembach, KR York, DG Green, JC Woodgate, BE TI Far Ultraviolet Spectroscopic Explorer observations of the low-redshift Ly beta forest SO ASTROPHYSICAL JOURNAL LA English DT Article DE intergalactic medium; quasars : absorption lines; ultraviolet : galaxies ID ABSORPTION-LINE SYSTEMS; INTERGALACTIC MEDIUM; ALPHA FOREST; CLOUDS; VOIDS; HALO AB We describe a moderate-resolution (20-25 km s(-1)) Far Ultraviolet Spectroscopic Explorer (FUSE) study of the low-redshift intergalactic medium. We report on studies of seven extragalactic sight lines and 12 Ly beta absorbers that correspond to Ly alpha lines detected by Hubble Space Telescope (HST)/Goddard High Resolution Spectrograph and Space Telescope imaging Spectrograph. These absorbers appear to contain a significant fraction of the low-z baryons and were a major discovery of the HST spectrographs. Using FUSE data, with 40 m Angstrom (4 sigma) Ly beta detection limits, we have employed the equivalent width ratio of Ly beta/Ly alpha, and occasionally higher Lyman lines, to determine the Doppler parameter b and accurate column densities N-H, for moderately saturated lines. We detect Ly beta absorption corresponding to all Ly alpha lines with W-lambda greater than or equal to 200 m Angstrom. The Ly beta/Ly alpha ratios yield a preliminary distribution function of Doppler parameters, with mean (b) = 31.4 +/- 7.4 km s(-1) and median 28 km s(-1), comparable to values at redshifts z = 2.0-2.5. If thermal, these b-values correspond to T-H1 approximate to 50,000 K, although the inferred Doppler parameters are considerably less than the widths derived from Ly alpha profile fitting, (b/b(width)) = 0.52. The typical increase in column density over that derived from profile fitting is Delta log N-H1 = 0.3, but ranges up to 1.0 dex. Our data suggest that the low-z Lya, absorbers contain sizable nonthermal motions or velocity components in the line profile, perhaps arising from cosmological expansion and infall. C1 Univ Colorado, Ctr Astrophys & Space Astron, Boulder, CO 80309 USA. Univ Colorado, Dept Astrophys & Planetary Sci, Boulder, CO 80309 USA. Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. Natl Inst Stand & Technol, Gaithersburg, MD USA. Princeton Univ, Dept Astrophys Sci, Princeton, NJ 08544 USA. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. Univ Wisconsin, Dept Astron, Madison, WI 53706 USA. Univ Chicago, Dept Astron & Astrophys, Chicago, IL 60637 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Shull, JM (reprint author), Univ Colorado, Ctr Astrophys & Space Astron, Campus Box 391, Boulder, CO 80309 USA. RI Oegerle, William/C-9070-2012; Woodgate, Bruce/D-2970-2012; Jenkins, Edward/P-5684-2014 OI Jenkins, Edward/0000-0003-1892-4423 NR 32 TC 38 Z9 38 U1 0 U2 1 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 JUL 20 PY 2000 VL 538 IS 1 BP L13 EP L16 DI 10.1086/312781 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 343ML UT WOS:000088706100003 ER PT J AU Reipa, V Holden, MJ Mayhew, MP Vilker, VL AF Reipa, V Holden, MJ Mayhew, MP Vilker, VL TI Temperature dependence of the formal reduction potential of putidaredoxin SO BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS LA English DT Article DE cytochrome P450; ferredoxin; reduction potential; redox reaction entropy; spectroelectrochemistry ID BIS(4-PYRIDYL)DISULFIDE-MODIFIED GOLD ELECTRODE; HEART CYTOCHROME-C; PYROCOCCUS-FURIOSUS; CONFORMATIONAL-CHANGES; BACKBONE DYNAMICS; REDOX; FERREDOXIN; ELECTROCHEMISTRY; THERMODYNAMICS; COORDINATION AB Putidaredoxin (Pdx), a [2Fe-2S] redox protein of size M-r 11 600, transfers two electrons in two separate steps from the flavin containing putidarecloxin reductase to the heme protein, cytochrome CYP101 in the P450cam catalytic cycle. It has recently come to light, through NMR measurements, that there can be appreciable differences in the Pdx conformational dynamics between its reduced and oxidized states. The redox reaction entropy, Delta S-rc(0') = (S-Pdxr(0')-SOPdxo0'), as determined from measurements of the variation ill formal potential with temperature, E-0'(T), provides a measure of the strength of this influence on Pdx function. We designed a spectroelectrochemical cell using optically transparent tin oxide electrodes, without fixed or diffusible mediators, to measure E-0'(T) over the temperature range 0-40 degrees C. The results indicate that the redox reaction entropy for Pdx is biphasic, decreasing from -213 +/- 27 J mol(-1) K-1 over 0-27 degrees C, to -582 +/- 150 J mol(-1) K-1 over 27-40 degrees C. These redox reaction entropy changes are significantly more negative than the changes reported for most cytochromes, although our measurement over the temperature interval 0-27 degrees C is in the range reported for other iron-sulfur proteins. This suggests that Pdx (and other ferredoxins) is a less rigid system than monohemes, and that redox-linked changes in conformation, and/or conformational dynamics, impart to these proteins the ability to interact with a number of redox partners. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Natl Inst Stand & Technol, Div Biotechnol, Gaithersburg, MD 20899 USA. RP Vilker, VL (reprint author), Natl Inst Stand & Technol, Div Biotechnol, Stop 8312, Gaithersburg, MD 20899 USA. NR 38 TC 17 Z9 17 U1 1 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0005-2728 J9 BBA-BIOENERGETICS JI Biochim. Biophys. Acta-Bioenerg. PD JUL 20 PY 2000 VL 1459 IS 1 BP 1 EP 9 DI 10.1016/S0005-2728(00)00108-0 PG 9 WC Biochemistry & Molecular Biology; Biophysics SC Biochemistry & Molecular Biology; Biophysics GA 344BP UT WOS:000088738000001 PM 10924895 ER PT J AU Soden, BJ AF Soden, BJ TI Atmospheric physics - Enlightening water vapour SO NATURE LA English DT Editorial Material C1 Princeton Univ, NOAA, Geophys Fluid Dynam Lab, Princeton, NJ 08542 USA. RP Soden, BJ (reprint author), Princeton Univ, NOAA, Geophys Fluid Dynam Lab, Box 308, Princeton, NJ 08542 USA. NR 3 TC 7 Z9 8 U1 1 U2 1 PU MACMILLAN PUBLISHERS LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD JUL 20 PY 2000 VL 406 IS 6793 BP 247 EP 248 DI 10.1038/35018666 PG 2 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 335PM UT WOS:000088251900030 ER PT J AU McFadden, GB Coriell, SR Sekerka, RF AF McFadden, GB Coriell, SR Sekerka, RF TI Effect of surface free energy anisotropy on dendrite tip shape SO ACTA MATERIALIA LA English DT Article DE dendritic growth; diffusion; phase transformations; theory & modeling ID PATTERN SELECTION; GROWTH; SUCCINONITRILE; MICROGRAVITY; MORPHOLOGY; TENSION AB In previous work, approximate solutions were found for paraboloids having perturbations with four-fold axial symmetry in order to model dendritic growth in cubic materials. These solutions provide self-consistent corrections through second order in a shape parameter epsilon to the Peclet number vs supercooling relation of the Ivantsov solution. The parameter epsilon is proportional to the amplitude of the four-fold correction to the dendrite shape, as measured from the Ivantsov paraboloid of revolution. The equilibrium shape for anisotropic surface free energy to second order in the anisotropy is calculated. The value of epsilon is determined by comparing the dendrite tip shape with the portion of the equilibrium shape near the growth direction, [001], for anisotropic surface free energy of the form gamma = gamma(0)[1 + 4(epsilon 4)(n(1)(4) + n(2)(4) + n(3)(4))], where the ni are components of the unit normal of the crystal surface. This comparison results in epsilon = -2(epsilon 4) - 24 epsilon(4)(2) + O(epsilon(4)(3)), independent of the Peclet number. From the experimental value of epsilon(4), it is found that epsilon approximate to -0.012 +/- 0.004, in good agreement with the measured value epsilon approximate to -0.008 of LaCombe et al. (Phys. Rev. E, 1995, 52, 2778) Published by Elsevier Science Ltd on behalf of Acta Metallurgica Inc. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Carnegie Mellon Univ, Pittsburgh, PA 15213 USA. RP McFadden, GB (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RI McFadden, Geoffrey/A-7920-2008 OI McFadden, Geoffrey/0000-0001-6723-2103 NR 20 TC 23 Z9 24 U1 0 U2 8 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 JUL 17 PY 2000 VL 48 IS 12 BP 3177 EP 3181 DI 10.1016/S1359-6454(00)00105-1 PG 5 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 352CK UT WOS:000089196800015 ER PT J AU Heene, M Wipf, H Udovic, TJ Rush, JJ AF Heene, M Wipf, H Udovic, TJ Rush, JJ TI Hydrogen vibrations and hydrogen trapping in TaN0.006H0.003 SO JOURNAL OF PHYSICS-CONDENSED MATTER LA English DT Article ID NIOBIUM; NITROGEN; INTERSTITIALS; METALS AB We studied, by neutron spectroscopy, local vibrations of hydrogen interstitials and hydrogen trapping by nitrogen interstitials in TaN0.006H0.003 and in a nitrogen-free TaH0.086 reference sample between 1.4 and 295 K. The measurements on TaH0.086 yielded vibrational energies E-1 = (113 +/- 1) meV and (doubly degenerate) E2,3 similar or equal to 163 meV at 295 K where hydrogen is in solid solution, together with a higher energy E-1 = (120 +/- 1) meV and essentially unchanged energies E2,3 at low temperatures (1.4 to 4.2 K) where hydrogen precipitates in a hydride phase. The energies agree with previous studies. The measurements on TaN0.006H0.003 yielded, at 295 K and at low temperatures, vibrational energies identical to those of the nitrogen-free sample at 295 K. The results show that the hydrogen interstitials are trapped by the nitrogen at low temperatures and do not precipitate. They show further that the trapped hydrogen interstitials occupy tetrahedral sites, i.e, the same type of site as occupied in the absence of traps. C1 Tech Univ Darmstadt, Inst Festkorperphys, D-64289 Darmstadt, Germany. NIST, Ctr Neutron Res, Gaithersburg, MD 20899 USA. RP Heene, M (reprint author), Tech Univ Darmstadt, Inst Festkorperphys, Hsch Str 6, D-64289 Darmstadt, Germany. NR 24 TC 3 Z9 3 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0953-8984 J9 J PHYS-CONDENS MAT JI J. Phys.-Condes. Matter PD JUL 17 PY 2000 VL 12 IS 28 BP 6183 EP 6190 DI 10.1088/0953-8984/12/28/314 PG 8 WC Physics, Condensed Matter SC Physics GA 341GH UT WOS:000088582300019 ER PT J AU Harris, JM Dlugokencky, EJ Oltmans, SJ Tans, PP Conway, TJ Novelli, PC Thoning, KW Kahl, JDW AF Harris, JM Dlugokencky, EJ Oltmans, SJ Tans, PP Conway, TJ Novelli, PC Thoning, KW Kahl, JDW TI An interpretation of trace gas correlations during Barrow, Alaska, winter dark periods, 1986-1997 SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID ATMOSPHERIC CARBON-DIOXIDE; AEROSOL BLACK CARBON; MAUNA-LOA; SURFACE OZONE; TROPOSPHERIC OZONE; ARCTIC ATMOSPHERE; POLAR SUNRISE; FLOW PATTERNS; METHANE; DESTRUCTION AB Positive correlations among CO, CO2, and CH4 during winter-spring have been observed at Barrow, Alaska, for many years. We examine these, as well as negative correlations between O-3 and these gases, during the winter dark period. Because biogenic and photochemical processes are limited within this environment, we believe that pollution is driving these relationships. The dearth of mixing processes within the Arctic basin, the strong stability of the winter boundary layer, and lack of sunlight (and hence low OH) contribute to the winter-spring maxima in CO, CO2, and CH4. We hypothesize that the negative correlation of O-3 with these gases is the result of O-3 titration by NO and NO2 (NOX) in industrial plumes, which leads to the destruction of one to two molecules of O-3 per NO emitted. Using the empirical slopes of O-3/CO2 and O-3/CO determined from 12 years of Barrow data, we derived emission factors, Delta NOX/Delta CO2 and Delta NOX/Delta CO, assuming -1.5 O-3/NO because of titration. Comparing these with published emission factors for NOX, CO2, and CO from industrial processes, we found good agreement. This pollution signature is regionally widespread, although air parcels transported from the direction of Siberia have the highest mixing ratios of pollutant gases. Possible scenarios leading to these trace gas relationships are explored. C1 NOAA, Climate Monitoring & Diagnost Lab, Boulder, CO 80303 USA. Univ Wisconsin, Dept Geosci, Milwaukee, WI 53211 USA. RP Harris, JM (reprint author), NOAA, Climate Monitoring & Diagnost Lab, 325 Broadway, Boulder, CO 80303 USA. EM jharris@cmdl.noaa.gov NR 50 TC 19 Z9 21 U1 1 U2 6 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUL 16 PY 2000 VL 105 IS D13 BP 17267 EP 17278 DI 10.1029/2000JD900167 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 335GU UT WOS:000088236400004 ER PT J AU Moxim, WJ Levy, H AF Moxim, WJ Levy, H TI A model analysis of the tropical South Atlantic Ocean tropospheric ozone maximum: The interaction of transport and chemistry SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID BIOMASS BURNING EMISSIONS; TRACE-A; MAPPING SPECTROMETER; TOMS/SBUV MEASUREMENTS; SEASONAL-VARIATION; REACTIVE NITROGEN; COLUMN OZONE; GLOBAL MODEL; ATMOSPHERE; CARBON AB The meteorological and photochemical nature of the South Atlantic Ocean tropospheric column ozone maximum is examined by analyzing the Geophysical Fluid Dynamics Laboratory (GFDL) Global Chemical Transport Model (GCTM) simulation during the Southern Hemisphere late winter. An ozone maximum of greater than 40 Dobson units is produced by the GCTM over the South Atlantic Ocean. The model is evaluated against available meteorological and ozone data and found to be in good qualitative agreement with observed wind fields, satellite measurements of tropospheric column ozone, tropospheric column ozone produced from ozonesonde data, and vertical profiles from ozonesondes. A quantitative analysis is performed over an area of the South Atlantic Ocean essentially devoid of local NOx sources and for a time, September, when the regional tropospheric ozone mass is at a maximum. The tropospheric mass of reactive nitrogen transported into the region is a result of source contributions from lightning (49%), biomass burning (36%), and 15% from the remaining NOx sources (fossil fuel plus biogenic plus stratosphere plus aircraft). Even with the removal of biomass burning NOx from the ozone photochemical system, the GCTM still produces an oceanic tropospheric column ozone maximum, suggesting the ozone phenomenon existed before agricultural burning by humans. The structure of clean air CO/CH4 net chemistry consists of ozone production in the upper troposphere (+2.2 Tg/month), weak destruction in the middle troposphere (-1.8 Tg/month), and strong destruction in the lower troposphere (-4.2 Tg/month). Through photochemistry, the two largest NOx sources help control the vertical profile of ozone with lightning dominating in the upper troposphere, while the relative importance of biomass burning is virtually constant throughout the troposphere. A mass budget analysis of ozone over the tropospheric South Atlantic Ocean reveals that net mass transport of ozone into the domain is nearly balanced by net chemical destruction and deposition and that the mass transport into and out of the region are comparable to the chemical production and destruction terms. The three-dimensional circulation governing the ozone vertical structure is one of horizontal mass convergence and net chemical production supplying ozone to the upper troposphere which is fluxed downward by subsidence and removed in the boundary layer by net chemical destruction, deposition, and horizontal mass divergence. C1 Princeton Univ, Geophys Fluid Dynam Lab, Princeton, NJ 08543 USA. RP Moxim, WJ (reprint author), Princeton Univ, Geophys Fluid Dynam Lab, POB 308, Princeton, NJ 08543 USA. EM wm@gfdl.gov NR 66 TC 51 Z9 52 U1 1 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 JUL 16 PY 2000 VL 105 IS D13 BP 17393 EP 17415 DI 10.1029/2000JD900175 PG 23 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 335GU UT WOS:000088236400013 ER PT J AU Klein, M Gasiewski, AJ AF Klein, M Gasiewski, AJ TI Nadir sensitivity of passive millimeter and submillimeter wave channels to clear air temperature and water vapor variations SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID WIND-SPEED; MICROWAVE; PRECIPITATION; ABSORPTION; CLOUDS AB The upwelling microwave-to-submillimeter wave brightness temperature observed from above the Earth's atmosphere is sensitive to parameters such as pressure, temperature, water vapor, and hydrometeor content, and this sensitivity has been successfully used for passive vertical sounding of temperature and water vapor profiles. To determine optimal satellite observation strategies for future passive microwave instruments operating at frequencies above those now used, a study of the potential clear-air vertical sounding capabilities of all significant microwave oxygen and water vapor absorption lines in the frequency range from approximately 10 to 1000 GHz has been performed. The study is based on a second-order statistical climatological model covering four seasons, three latitudinal zones, and altitudes up to similar to 70 km. The climatological model was developed by comparing data from three sources: the Upper Atmosphere Research Satellite Halogen Occultation Experiment (UARS HALOE) instrument, the TIROS Operational Vertical Sounder (TOVS) Initial Guess Retrieval radiosonde set, and the NOAA advanced microwave sounder unit (AMSU) radiosonde set. The Liebe MPM87 absorption model is used for water vapor and oxygen absorption and considers the effects of ozone and isotope absorption. Variations in the vertical sounding capabilities due to statistical variations of water vapor and temperature with latitude and season around each line are considered, and useful channel sets for geostationary microwave vertical sounding are suggested. C1 NOAA, ETL, R E ETI, Boulder, CO 80303 USA. Univ Colorado, NOAA, CIRES, Boulder, CO 80309 USA. RP Klein, M (reprint author), NOAA, ETL, R E ETI, 325 Broadway, Boulder, CO 80303 USA. EM mklein@etl.noaa.gov; agasiewski@etl.noaa.gov NR 24 TC 16 Z9 17 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUL 16 PY 2000 VL 105 IS D13 BP 17481 EP 17511 DI 10.1029/2000JD900089 PG 31 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 335GU UT WOS:000088236400018 ER PT J AU Yu, ZJ Moore, DW AF Yu, ZJ Moore, DW TI Validating the NSCAT winds in the vicinity of the pacific intertropical convergence zone SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID TROPICAL PACIFIC; OCEAN; MODEL AB It is known that the NSCAT winds are influenced by precipitation, and so are potentially in error in regions of high rainfall, such as the Pacific ITCZ. We assess this potential error by comparing NSCAT winds to other products and by determining the possible impact on modeling the Pacific NECC. In the latitude band of the ITCZ, there are large differences between wind products from the ECMWF and NSCAT. A comparison with TAO buoy winds shows a bias of NSCAT data towards a higher zonal wind stress at 8 degrees N. The spatial distribution of this bias distorts the Ekman pumping velocity across the ITCZ, and results in a NECC that is 0.1-0.2 m/s weaker than that forced by the ECMWF winds. This is not a trivial amount during the spring, when the strength of the NECC in the eastern Pacific is of the same magnitude. C1 NOAA, Pacific Marine Environm Lab, OCRD, Seattle, WA 98115 USA. Univ Washington, Joint Inst Study Atmosphere & Oceans, Seattle, WA 98195 USA. RP Yu, ZJ (reprint author), NOAA, Pacific Marine Environm Lab, OCRD, 7600 Sand Point Way, Seattle, WA 98115 USA. RI MOORE, DENNIS/C-9901-2014 NR 14 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 JUL 15 PY 2000 VL 27 IS 14 BP 2121 EP 2124 DI 10.1029/1999GL011250 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 337AQ UT WOS:000088335500027 ER PT J AU Bouldin, CE Wallace, WE Lynn, GW Roth, SC Wu, WL AF Bouldin, CE Wallace, WE Lynn, GW Roth, SC Wu, WL TI Thermal expansion coefficients of low-k dielectric films from Fourier analysis of x-ray reflectivity SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID THIN-FILMS; SILICON AB We determine the thermal expansion coefficient of a fluorinated poly(arylene ether) low-k dielectric film using Fourier analysis of x-ray reflectivity data. The approach is similar to that used in Fourier analysis of x-ray absorption fine structure. The analysis compares two similar samples, or the same sample as an external parameter is varied, and determines the change in film thickness. The analysis process is very accurate and depends on no assumed model. We determine a thermal expansion coefficient of 55 +/- 9 x 10(-6) K(-1) using this approach. (C) 2000 American Institute of Physics. [S0021-8979(00)09913-8]. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Univ Tennessee, Dept Chem, Knoxville, TN 37996 USA. RP Bouldin, CE (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. EM bouldin@enh.nist.gov NR 14 TC 15 Z9 15 U1 0 U2 5 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD JUL 15 PY 2000 VL 88 IS 2 BP 691 EP 695 AR PII [S0021-8979(00)09913-8] DI 10.1063/1.373722 PG 5 WC Physics, Applied SC Physics GA 329DA UT WOS:000087889800014 ER PT J AU Bray, SL Ekin, JW Clickner, CC Masur, LJ AF Bray, SL Ekin, JW Clickner, CC Masur, LJ TI Transverse compressive stress effects on the critical current of Bi-2223/Ag tapes reinforced with pure Ag and oxide-dispersion-strengthened Ag SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID HIGH-TEMPERATURE SUPERCONDUCTORS; POWER; FIELD; WIRE AB We have measured the effect of transverse compressive stress on the critical current of two similar sets of Bi2Sr2Ca2Cu3Ox (Bi-2223) tapes in a direct comparison between tapes reinforced with pure Ag and oxide-dispersion-strengthened (ODS) Ag. The critical-current degradation at a transverse stress of 100 MPa was about 10% for the Bi-2223/pure Ag tapes and only about 3% for the ODS Ag tapes. In one case for each sample type the degradation was significantly greater, and there was an apparent correlation with porosity in the superconductor filaments. The degradation was the same for critical-current criteria from 5 mu V/cm down to 0.1 mu V/cm. (C) 2000 American Institute of Physics. [S0021-8979(00)01514-0]. C1 Natl Inst Stand & Technol, Boulder, CO 80303 USA. Amer Supercond Corp, Westborough, MA 01581 USA. RP Bray, SL (reprint author), Natl Inst Stand & Technol, 325 Broadway, Boulder, CO 80303 USA. NR 10 TC 9 Z9 9 U1 0 U2 1 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD JUL 15 PY 2000 VL 88 IS 2 BP 1178 EP 1180 DI 10.1063/1.373801 PG 3 WC Physics, Applied SC Physics GA 329DA UT WOS:000087889800089 ER PT J AU Alexander, MA Scott, JD Deser, C AF Alexander, MA Scott, JD Deser, C TI Processes that influence sea surface temperature and ocean mixed layer depth variability in a coupled model SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID CLIMATE-SYSTEM-MODEL; LOW-FREQUENCY VARIABILITY; NORTH-ATLANTIC OCEAN; PACIFIC WARM POOL; HEAT-FLUX; INTERANNUAL VARIABILITY; BOUNDARY-CONDITIONS; THERMAL RESPONSE; WESTERN PACIFIC; SST VARIABILITY AB A 50-year coupled atmosphere-ocean model integration is used to study sea surface temperature (SST) and mixed layer depth (h), and the processes which influence them. The model consists of an atmospheric general circulation model coupled to an ocean mixed layer model in ice-free regions. The midlatitude SST variability is simulated fairly well, although the maximum variance is underestimated and located farther south than observed. The model is clearly deficient in the vicinity of the Gulf Stream and in the eastern tropical Pacific where advective processes are important. The model generally reproduces the observed structure of the mean h in both March and September but underestimates it in the North Atlantic during winter. The net surface heat flux strongly regulates both the mean ((-)) and the anomalous (') SSTs throughout the year. The entrainment heat flux, which is proportional to the product of the entrainment rate (W-e) and the temperature jump at the base of the mixed layer (Delta T), influences SSTs in summer and fall, especially north of similar to 35 degrees N (45 degrees N) in the Pacific (Atlantic). W(e)Delta T is more important for the development of SST' in fall compared to W(e)Delta T, which is larger in summer. The entrainment rate is dominated by wind-induced mixing in summer and surface buoyancy forcing in winter; the density jump at the base of the mixed layer is of secondary importance. In addition, anomalies in h have a significant impact on the heat balance of the mixed layer during spring and summer. Deep winter mixed layers and the storage of thermal anomalies beneath the shallow mixed layer in summer leads to large winter-to-winter persistence of SST anomalies in the far North Atlantic, in accord with observations and stochastic climate theory. C1 Univ Colorado, NOAA, CIRES, Climate Diagnost Ctr, Boulder, CO 80303 USA. Natl Ctr Atmospher Res, Boulder, CO 80303 USA. RP Alexander, MA (reprint author), Univ Colorado, NOAA, CIRES, Climate Diagnost Ctr, R-CDC1,325 Broadway, Boulder, CO 80303 USA. RI Alexander, Michael/A-7097-2013 OI Alexander, Michael/0000-0001-9646-6427 NR 100 TC 58 Z9 59 U1 1 U2 6 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-OCEANS JI J. Geophys. Res.-Oceans PD JUL 15 PY 2000 VL 105 IS C7 BP 16823 EP 16842 DI 10.1029/2000JC900074 PG 20 WC Oceanography SC Oceanography GA 335TJ UT WOS:000088260600003 ER PT J AU Ezer, T AF Ezer, T TI On the seasonal mixed layer simulated by a basin-scale ocean model and the Mellor-Yamada turbulence scheme SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID FLOWS AB Seasonal changes and vertical mixing processes in the upper layers of the North Atlantic Ocean are simulated with a basin-scale sigma coordinate ocean model that uses the Mellor-Yamada turbulence closure scheme. The cause of insufficient surface mixing and a too shallow summertime thermocline, common problems of ocean models of this type, is investigated in detail by performing a series of sensitivity experiments with different surface forcing conditions and different turbulence parameterizations. A recent improvement in the parameterization of the dissipation term in the Mellor-Yamada turbulence scheme, which has shown a significant improvement in one-dimensional calculations, had a positive but relatively small influence on the three-dimensional calculations. The results quantify the improvement in the model upper ocean thermal structure as surface forcing becomes more realistic from one experiment to another, for example, when monthly mean winds are replaced by 6 hour variable winds. The inclusion of shortwave radiation penetration is especially important to prevent overly shallow model mixed layers during the summer and seems to affect not only the surface layer but also the thermal structure of the upper 200 m of the ocean. The difficulty of evaluating turbulent mixing processes in three-dimensional models due to errors in surface fluxes, spatial changes, and three-dimensional effects, as shown here, points to the important role still left for one-dimensional turbulence models in improving parameterizations used in three-dimensional realistic models. C1 Princeton Univ, Program Atmospher & Ocean Sci, Princeton, NJ 08544 USA. RP Ezer, T (reprint author), Princeton Univ, Program Atmospher & Ocean Sci, POB CN710,Sayre Hall, Princeton, NJ 08544 USA. OI Ezer, Tal/0000-0002-2018-6071 NR 29 TC 50 Z9 59 U1 1 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-OCEANS JI J. Geophys. Res.-Oceans PD JUL 15 PY 2000 VL 105 IS C7 BP 16843 EP 16855 DI 10.1029/2000JC900088 PG 13 WC Oceanography SC Oceanography GA 335TJ UT WOS:000088260600004 ER PT J AU Lefebvre, AA Lee, JH Balsara, NP Hammouda, B AF Lefebvre, AA Lee, JH Balsara, NP Hammouda, B TI Fluctuations in highly metastable polymer blends SO JOURNAL OF POLYMER SCIENCE PART B-POLYMER PHYSICS LA English DT Article DE metastability; polymer blends; small-angle neutron scattering C1 Polytech Univ, Dept Chem Engn & Chem, Metrotech Ctr 6, Brooklyn, NY 11201 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Balsara, NP (reprint author), Polytech Univ, Dept Chem Engn & Chem, Metrotech Ctr 6, Brooklyn, NY 11201 USA. NR 9 TC 7 Z9 7 U1 1 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 JUL 15 PY 2000 VL 38 IS 14 BP 1926 EP 1930 DI 10.1002/1099-0488(20000715)38:14<1926::AID-POLB110>3.0.CO;2-3 PG 5 WC Polymer Science SC Polymer Science GA 325AT UT WOS:000087654700011 ER PT J AU Audebert, M Radicella, JP Dizdaroglu, M AF Audebert, M Radicella, JP Dizdaroglu, M TI Effect of single mutations in the OGG1 gene found in human tumors on the substrate specificity of the Ogg1 protein SO NUCLEIC ACIDS RESEARCH LA English DT Article ID OXIDATIVE DNA-DAMAGE; CHROMATOGRAPHY-MASS-SPECTROMETRY; SACCHAROMYCES-CEREVISIAE; COLON-CANCER; HOGG1 GENE; REPAIR; 8-HYDROXYGUANINE; GLYCOSYLASE; EXCISION; LESIONS AB We have investigated the effect of single amino acid substitutions of conserved arginines on the catalytic activities of the human Ogg1 protein (alpha-hOgg1-Ser(326)) (wild-type alpha-hOgg1). Mutant forms of hOgg1 with mutations Arg(46)-->Gln (alpha-hOgg1-Gln(46)) and Arg(154)-->His (alpha-hOgg1-His(154)) have previously been identified in human tumors. The mutant proteins alpha-hOgg1-Gln(46) and alpha-hOgg1-His(154) were expressed in Escherichia coli and purified to homogeneity. The substrate specificities of these proteins and wild-type alpha-hOgg1 were investigated using gamma-irradiated DNA and the technique of gas chromatography/isotope-dilution mass spectrometry. All three enzymes excised 2,6-diamino-4-hydroxy-5-formamidopyrimidine (FapyGua) and 8-hydroxyguanine (8-OH-Gua) from gamma-irradiated DNA containing a multiplicity of base lesions. Michaelis-Menten kinetics of excision were measured. Significant differences between excision kinetics of these three enzymes were observed. Excision of FapyGua and 8-OH-Gua by wild-type alpha-hOgg1 was greater than that by alpha-hOgg1-Gln(46) and alpha-hOgg1-His(154) The latter mutant protein was less active than the former. The diminished activity of the mutant proteins was more pronounced for 8-OH-Gua than for FapyGua. Cleavage assays were also performed using P-32-labeled 34mer oligonucleotide duplexes containing a single 8-OH-Gua paired to each of the four DNA bases. The results obtained with the oligonucleotide containing the 8-OH-Gua/Cyt pair were in good agreement with those observed with gamma-irradiated DNA. Wild-type alpha-hOgg1 and its mutants repaired the three mismatches less efficiently than the 8-OH-Gua/ Cyt pair. The substitution of Arg(154), in addition to diminishing the activity on 8-OH-Gua, relaxes the selectivity found in the wild-type alpha-hOgg1 for the base opposite 8-OH-Gua. Taken together the results show that the mutant forms alpha-hOgg1-Gln(46) and alpha-hOgg1-His(154) found in human tumors are defective in their catalytic capacities. C1 Natl Inst Stand & Technol, Chem Sci & Technol Lab, Gaithersburg, MD 20899 USA. CEA, Dept Radiobiol & Radiopathol, CNRS, UMR 217, F-92265 Fontenay Aux Roses, France. RP Dizdaroglu, M (reprint author), Natl Inst Stand & Technol, Chem Sci & Technol Lab, Bldg 227-A239,MS8311, Gaithersburg, MD 20899 USA. RI AUDEBERT, Marc/C-1153-2008 NR 33 TC 84 Z9 89 U1 0 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 JUL 15 PY 2000 VL 28 IS 14 BP 2672 EP 2678 DI 10.1093/nar/28.14.2672 PG 7 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 338PB UT WOS:000088427500007 PM 10908322 ER PT J AU Karen, P Kjekshus, A Huang, Q Karen, V Mighell, AD Santoro, A AF Karen, P Kjekshus, A Huang, Q Karen, V Mighell, AD Santoro, A TI Neutron powder diffraction study of the crystal structure of the oxycarbonate phase YBa2Cu2.85(CO3)(0.15)O-6.73 SO PHYSICA C LA English DT Article DE neutron powder diffraction; crystal structure; YBa2C2.85(CO3)(0.15)O-6.73; oxycarbonate ID CO3 GROUPS; COPPER; SUBSTITUTION; YBA2CU3O6+X; CHEMISTRY; SYSTEM AB The oxycarbonate phase YBa2Cu2.85(CO3)(0.15)O-6.73 has been analyzed by neutron powder diffraction. The phase crystallizes with the symmetry of space group P4/mmm and with unit cell parameters a = 3.8717(3), c = 11.60(1) Angstrom. Rietveld refinements show that the basic structure of the oxycarbonate is the same as that of the 193 superconductor YBa2Cu3O6+w. The CO32- ions are located on the basal plane of the unit cell, with the carbon atoms replacing an equal number of "chain" copper atoms. The presence of the CO32- defects explains why the oxygen stoichiometry of the oxycarbonate can he larger than seven atoms per formula unit. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Oslo, Dept Chem, N-0315 Oslo 3, Norway. Univ Maryland, College Pk, MD 20742 USA. Natl Inst Stand & Technol, Ctr Neutron Res, Gaithersburg, MD 20899 USA. RP Kjekshus, A (reprint author), Univ Oslo, Dept Chem, POB 1033, N-0315 Oslo 3, Norway. RI Karen, Pavel/A-9062-2008 OI Karen, Pavel/0000-0003-2937-6477 NR 17 TC 5 Z9 5 U1 1 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD JUL 15 PY 2000 VL 336 IS 3-4 BP 279 EP 286 DI 10.1016/S0921-4534(00)00275-6 PG 8 WC Physics, Applied SC Physics GA 336AR UT WOS:000088280200016 ER PT J AU Kent, ML Myers, MS AF Kent, ML Myers, MS TI Hepatic lesions in a redstriped rockfish (Sebastes proriger) suggestive of a herpesvirus infection SO DISEASES OF AQUATIC ORGANISMS LA English DT Article DE herpesvirus; rockfish; liver lesions AB Unusual lesions were observed in a redstriped rockfish (Sebastes proriger) collected during a survey of marine fishes off the coast of British Columbia, Canada. This particular fish exhibited prominent hepatomegaly, with large, coalescing, multiple hemorrhages. The affected Liver exhibited remarkable histological changes that, taken together, strongly suggested infection by a virus of the herpesvirus group. Multiple, multinucleated giant cells or syncytia of hepatocytes occurred throughout the Liver and were associated with massive, coalescing areas of coagulation necrosis, edema, congestion and cavernous hemorrhages (peliosis hepatis) with thrombosis. In addition, the liver showed multifocal inflammation, characterized by perivascular and peribiliary cuffing of mononuclear inflammatory cells. High magnification of the syncytia revealed that the nuclei were pleomorphic, hyperchromatic, and typically contained eosinophilic to densely amphophilic inclusion bodies of varying size, closely resembling Cowdry Type A inclusions. These inclusions stained red to purple in Feulgen's stain, indicating presence of DNA. Electron-lucent spheres (similar to 100 nm diameter) were observed within hepatocyte nuclei by transmission electron microscopy, suggestive of herpesvirus capsids. To our knowledge, this is the first report of a putative or confirmed herpesvirus infection in any rockfish of the genus Sebastes. C1 Dept Microbiol, Ctr Salmon Dis Res, Corvallis, OR 97331 USA. NOAA, Natl Marine Fisheries Serv, NW & Alaska Fisheries Ctr, Environm Conservat Div, Seattle, WA 98112 USA. RP Kent, ML (reprint author), Dept Microbiol, Ctr Salmon Dis Res, 220 Nash Hall, Corvallis, OR 97331 USA. NR 10 TC 7 Z9 7 U1 0 U2 1 PU INTER-RESEARCH PI OLDENDORF LUHE PA NORDBUNTE 23, D-21385 OLDENDORF LUHE, GERMANY SN 0177-5103 J9 DIS AQUAT ORGAN JI Dis. Aquat. Org. PD JUL 14 PY 2000 VL 41 IS 3 BP 237 EP 239 DI 10.3354/dao041237 PG 3 WC Fisheries; Veterinary Sciences SC Fisheries; Veterinary Sciences GA 349LU UT WOS:000089047200010 PM 10950187 ER PT J AU Bergman, JW Hendon, HH AF Bergman, JW Hendon, HH TI Cloud radiative forcing of the low-latitude tropospheric circulation: Linear calculations SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID TROPICAL PACIFIC; SOLAR-RADIATION; ANNUAL CYCLE; EL-NINO; OCEAN; HEAT; MODEL; GCM; REANALYSES; ABSORPTION AB The role of clouds for low-latitude atmospheric circulations is examined in a linearized calculation forced by diabatic heating rates. A comparison of the circulation calculated from total diabatic heating, obtained from reanalysis data, with observed fields determines which aspects of the calculation are realistic and which are not. The rule of clouds is quantified by the circulation calculated from atmospheric cloud radiative forcing, which, in turn, has been calculated with the National Center for Atmospheric Research radiative transfer model using cloud properties observed in the International Satellite Cloud Climatology Project. In general, cloud radiative forcing contributes about 20% to the magnitude of low-latitude circulations. It typically reinforces the circulation that is driven by convective latent heating. Cloud radiative forcing tends to have a stronger influence in the lower troposphere than at upper levels. It influences local circulations more than remote ones. In particular, cloud radiative forcing from local low cloud cover is the dominant source of diabatic heating influencing subtropical circulations over the eastern oceans. Cloud radiative forcing from low clouds is also found to be important for seasonal variations of meridional winds over the cold tongue in the eastern Pacific. This indicates that atmospheric cloud radiative forcing, and not just surface forcing, is important for ocean-atmospheric coupling there. Additional calculations are performed that test the sensitivity of the atmospheric circulation to different sources of diabatic heating rates. These sources include radiative heating rates that have been calculated from different cloud data, different cloud overlap assumptions, and enhanced cloud short-wave absorptivity. The principal conclusions of this investigation are unchanged by these calculations. However, enhanced short-wave absorption by clouds systematically reduces the impact of clouds on atmospheric circulations. C1 Univ Colorado, NOAA, Cooperat Inst Res Environm Sci, Climate Diagnost Ctr, Boulder, CO 80309 USA. RP Bergman, JW (reprint author), Univ Colorado, NOAA, Cooperat Inst Res Environm Sci, Climate Diagnost Ctr, R-E-CD1,325 Broadway, Boulder, CO 80309 USA. NR 35 TC 29 Z9 29 U1 0 U2 5 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PD JUL 14 PY 2000 VL 57 IS 14 BP 2225 EP 2245 DI 10.1175/1520-0469(2000)057<2225:CRFOTL>2.0.CO;2 PG 21 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 338LX UT WOS:000088422300002 ER PT J AU Bartels, R Backus, S Zeek, E Misoguti, L Vdovin, G Christov, IP Murnane, MM Kapteyn, HC AF Bartels, R Backus, S Zeek, E Misoguti, L Vdovin, G Christov, IP Murnane, MM Kapteyn, HC TI Shaped-pulse optimization of coherent emission of high-harmonic soft X-rays SO NATURE LA English DT Article ID LASER-PULSES; QUANTUM CONTROL; RARE-GASES; GENERATION; DYNAMICS; TRANSITIONS; COMPRESSION AB When an intense laser pulse is focused into a gas, the light-atom interaction that occurs as atoms are ionized results in an extremely nonlinear optical process(1-3)-the generation of high harmonics of the driving laser frequency. Harmonics that extend up to orders of about 300 have been reported(4,5), some corresponding to photon energies in excess of 500 eV. Because this technique is simple to implement and generates coherent, laser-like, soft X-ray beams, it is currently being developed for applications in science and technology; these include probing the dynamics in chemical and materials systems(6) and imaging(7). Here we report that by carefully tailoring the shape(8) of intense light pulses, we can control(9,10) the interaction of light with an atom during ionization, improving the efficiency of X-ray generation by an order of magnitude. We demonstrate that it is possible to tune the spectral characteristics of the emitted radiation, and to steer the interaction between different orders of nonlinear processes. C1 Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. Univ Colorado, Dept Phys, Boulder, CO 80309 USA. Natl Inst Stand & Technol, Boulder, CO 80309 USA. Delft Univ Technol, NL-2600 GA Delft, Netherlands. Univ Sofia, Dept Phys, BU-1126 Sofia, Bulgaria. RP Kapteyn, HC (reprint author), Univ Colorado, Joint Inst Lab Astrophys, Campus Box 440, Boulder, CO 80309 USA. EM kapteyn@jila.colorado.edu RI Backus, Sterling/C-2506-2008; Zeek, Erik/A-6664-2011; Misoguti, Lino/C-2462-2012; Kapteyn, Henry/H-6559-2011; Christov, Ivan/D-4446-2014 OI Misoguti, Lino/0000-0001-6624-8453; Kapteyn, Henry/0000-0001-8386-6317; Christov, Ivan/0000-0002-9146-6708 NR 30 TC 557 Z9 561 U1 14 U2 66 PU NATURE PUBLISHING GROUP PI LONDON PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD JUL 13 PY 2000 VL 406 IS 6792 BP 164 EP 166 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 335BA UT WOS:000088221100040 ER PT J AU Scala, A Starr, FW La Nave, E Sciortino, F Stanley, HE AF Scala, A Starr, FW La Nave, E Sciortino, F Stanley, HE TI Configurational entropy and diffusivity of supercooled water SO NATURE LA English DT Article ID LIQUIDS; GLASSES; ENERGY AB As a liquid approaches the glass transition, its properties are dominated by local potential minima(1,2) in its energy landscape. The liquid experiences localized vibrations in the basins of attraction surrounding the minima, and rearranges via relatively infrequent inter-basin jumps(3). As a result, the liquid dynamics at low temperature are related to the system's exploration of its own configuration space. The 'thermodynamic approach' to the glass transition considers the reduction in configuration space(4-8) explored as the system cools, and predicts that the configurational entropy(5,9,10) (a measure of the number of local potential energy minima sampled by the liquid) is related to the diffusion constant. Here we report a stringent test of the thermodynamic approach for liquid water (a convenient system to study because of an anomalous pressure dependence in the diffusion constant). We calculate the configurational entropy at points spanning a large region of the temperature-density plane, using a model(11) that reproduces the dynamical anomalies of liquid water. We find that the thermodynamic approach can be used to understand the characteristic dynamic anomalies, and that the diffusive dynamics are governed by the configurational entropy. Our results indicate that the thermodynamic approach might be extended to predict the dynamical behaviour of supercooled liquids in general. C1 Boston Univ, Ctr Polymer Studies, Boston, MA 02215 USA. Boston Univ, Ctr Computat Sci, Boston, MA 02215 USA. Boston Univ, Dept Phys, Boston, MA 02215 USA. Univ Rome La Sapienza, Dipartimento Fis, I-00185 Rome, Italy. Univ Rome La Sapienza, Ist Nazl Fis Mat, I-00185 Rome, Italy. RP Scala, A (reprint author), Natl Inst Stand & Technol, Div Polymers, Gaithersburg, MD 20899 USA. RI Sciortino, Francesco/B-4768-2012; Starr, Francis/C-7703-2012; Scala, Antonio/A-2098-2012 OI Scala, Antonio/0000-0002-3414-2686 NR 29 TC 269 Z9 271 U1 0 U2 41 PU MACMILLAN PUBLISHERS LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD JUL 13 PY 2000 VL 406 IS 6792 BP 166 EP 169 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 335BA UT WOS:000088221100041 ER PT J AU Petralli-Mallow, TP Plant, AL Lewis, ML Hicks, JM AF Petralli-Mallow, TP Plant, AL Lewis, ML Hicks, JM TI Cytochrome c at model membrane surfaces: Exploration via second harmonic generation-circular dichroism and surface-enhanced resonance Raman spectroscopy SO LANGMUIR LA English DT Article ID SELF-ASSEMBLED MONOLAYERS; 2ND-HARMONIC GENERATION; PHOSPHOLIPID MONOLAYERS; BILAYER-MEMBRANES; OPTICAL-ACTIVITY; ADSORPTION; BINDING; GOLD; CHIRALITY; INTERFACE AB The novel nonlinear optical method of second harmonic generation-circular dichroism (SHG-CD) has been used to follow the adsorption and redox properties of a peripheral membrane protein, horse heart cytochrome c, adsorbed at several model membrane surfaces. The SHG-CD response is shown to be affected by the oxidation state of the heme within surface-adsorbed cytochrome c, as is consistent with the sensitivity of SHG to the chirality of the heme. SHG-CD measurements show that adsorbed cytochrome c is reducible by ascorbate at alkanethiol surfaces, but not at phospholipid/alkanethiol hybrid bilayer membranes (HBMs). The adsorption of cytochrome c at the model membrane surfaces was verified by surface plasmon resonance. Surface-enhanced resonance Raman measurements show that cytochrome c adsorbed on a hybrid bilayer membrane retains the Fe-heme conformation associated with solution-phase cytochrome c and is reducible by applying potential to the supporting electrode. The inability of ascorbic acid to reduce cytochrome c associated with the HEM is attributed not to a change in its redox potential, but rather to the nature of the interaction of cytochrome c with the HBM. C1 Natl Inst Stand & Technol, Div Biotechnol, Gaithersburg, MD 20899 USA. Univ Denver, Dept Chem, Denver, CO 80208 USA. Georgetown Univ, Dept Chem, Washington, DC 20057 USA. RP Petralli-Mallow, TP (reprint author), Natl Inst Stand & Technol, Div Biotechnol, Gaithersburg, MD 20899 USA. NR 39 TC 34 Z9 35 U1 1 U2 18 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0743-7463 J9 LANGMUIR JI Langmuir PD JUL 11 PY 2000 VL 16 IS 14 BP 5960 EP 5966 DI 10.1021/la9913250 PG 7 WC Chemistry, Multidisciplinary; Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA 332BD UT WOS:000088052400021 ER PT J AU Ma, XL Wan, ZM Moeller, CC Menzel, WP Gumley, LE Zhang, YL AF Ma, XL Wan, ZM Moeller, CC Menzel, WP Gumley, LE Zhang, YL TI Retrieval of geophysical parameters from Moderate Resolution Imaging Spectroradiometer thermal infrared data: Evaluation of a two-step physical algorithm SO APPLIED OPTICS LA English DT Article ID SATELLITE SOUNDING RADIANCES; NONLINEAR OPTIMAL ESTIMATION; TERRESTRIAL MATERIALS; SURFACE TEMPERATURE; ATMOSPHERIC WINDOW; EMISSIVITY; VEGETATION; INVERSION; PROFILES; CLOUD AB A two-step physical algorithm that simultaneously retrieves geophysical parameters from Moderate Resolution Imaging Spectroradiometer (MODIS) measurements was developed. The retrieved geophysical parameters include atmospheric temperature-humidity profile, surface skin temperature, and two surface emissivities within the shortwave (3-5-mu m) and the longwave (8-14.5-mu m) regions. The physical retrieval is accomplished in two steps: (i) The Tikhonov regularization method is employed to generate a regularization solution along with an optimum regularization parameter; (ii) the nonlinear Newtonian iteration algorithm is carried out with the regularization solution as a first-guess profile to obtain a final maximum probability solution for geophysical parameters. The algorithm was tested with both simulated and real MODIS Airborne Simulator (MAS) data. Sensitivity studies on simulated MAS data demonstrate that simultaneous retrievals of land and atmospheric parameters improve the accuracy of the retrieved geophysical parameters. Finally, analysis and accuracy of retrievals from real MAS data are discussed. (C) 2000 Optical Society of America. OCIS codes: 280.0280, 030.5620. C1 Univ Calif Santa Barbara, Inst Computat Earth Syst Sci, Santa Barbara, CA 93106 USA. Univ Wisconsin, Cooperat Inst Meteorol Satellite Studies, Madison, WI 53706 USA. Natl Environm Satellite Data & Informat Serv, Off Res & Applicat, Natl Ocean & Atmospher Adm, Madison, WI 53706 USA. RP Ma, XL (reprint author), Univ Calif Santa Barbara, Inst Computat Earth Syst Sci, Santa Barbara, CA 93106 USA. EM xma@icess.ucsb.edu RI Menzel, W. Paul/B-8306-2011 OI Menzel, W. Paul/0000-0001-5690-1201 NR 48 TC 31 Z9 36 U1 2 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 JUL 10 PY 2000 VL 39 IS 20 BP 3537 EP 3550 DI 10.1364/AO.39.003537 PG 14 WC Optics SC Optics GA 332AH UT WOS:000088050500014 PM 18349925 ER PT J AU Embley, RW Chadwick, WW Perfit, MR Smith, MC Delaney, JR AF Embley, RW Chadwick, WW Perfit, MR Smith, MC Delaney, JR TI Recent eruptions on the CoAxial segment of the Juan de Fuca Ridge: Implications for mid-ocean ridge accretion processes SO JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH LA English DT Article ID EAST PACIFIC RISE; SEA MARC-I; OVERLAPPING SPREADING CENTERS; RECENT LAVA FLOWS; VOLCANIC-ERUPTION; AXIAL-VOLCANO; MIDOCEAN RIDGE; CLEFT SEGMENT; CRUSTAL ACCRETION; RIFT-VALLEY AB The 1993 seismic swarm and volcanic eruption on the CoAxial segment of the Juan de Fuca Ridge was the first verified mid-ocean ridge accretion event monitored by the National Oceanic and Atmospheric Administration/U.S. Navy Sound Surveillance System (SOSUS). Ambiguity in the location of the initial seismicity resulted in an uncertainty as to whether the dike intruded from the summit and north rift zone of the adjacent Axial Volcano or whether it arose locally within the CoAxial segment. However, analyses of multibeam, side-scan sonar, towed camera, submersible, and geochemical data show that the CoAxial segment is morphologically, structurally, and geochemically distinct from the north rift zone of Axial Volcano. There is no geologic or geochemical evidence that dike injections from Axial Volcano have extended north of 46 degrees 18'N in the past, whereas the 1993 eruption site is at 46 degrees 31'N. Furthermore, all seafloor manifestations of the 1993 dike injection lie along the central neovolcanic zone of the CoAxial segment. Analyses of repeat SeaBeam surveys combined with seafloor observations show that two other eruptions of approximately the same volume as the 1993 eruption occurred along the CoAxial segment in the 1981-1991 interval. These three diking events may have relieved decades of accumulated stress over similar to 35 km or more of this segment. The spatial pattern and hydrothermal history of the 1993 event is consistent with a dike with a significant lateral component of injection. C1 NOAA, Hatfield Marine Sci Ctr, Pacific Marine Environm Lab, Newport, OR 97365 USA. Oregon State Univ, Hatfield Marine Sci Ctr, CIMRS, Newport, OR 97365 USA. Univ Washington, Sch Oceanog, Seattle, WA 98195 USA. Univ Florida, Dept Geol, Gainesville, FL 32611 USA. RP Embley, RW (reprint author), NOAA, Hatfield Marine Sci Ctr, Pacific Marine Environm Lab, 2115 SE OSU Dr, Newport, OR 97365 USA. EM embley@pmel.noaa.gov; chadwick@pmel.noaa.gov; perf@nervm.nerdc.ufl.edu; jdelaney@u.washington.edu NR 75 TC 48 Z9 50 U1 0 U2 5 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9313 EI 2169-9356 J9 J GEOPHYS RES-SOL EA JI J. Geophys. Res.-Solid Earth PD JUL 10 PY 2000 VL 105 IS B7 BP 16501 EP 16525 DI 10.1029/2000JB900030 PG 25 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 335TZ UT WOS:000088262000030 ER PT J AU Ramillien, G Wright, IC AF Ramillien, G Wright, IC TI Predicted seafloor topography of the New Zealand region: A nonlinear least squares inversion of satellite altimetry data SO JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH LA English DT Article ID WESTERN BOUNDARY CURRENT; ERS-1 GEODETIC MISSION; SHIP-BORNE PROFILES; OBLIQUE SUBDUCTION; HIKURANGI PLATEAU; BATHYMETRIC PREDICTION; SEAMOUNT TOPOGRAPHY; MAGNETIC-ANOMALIES; SOUTHWEST PACIFIC; BASEMENT GEOLOGY AB We use a nonlinear least squares inversion to derive predicted seafloor topography (hereinafter referred to as RW99) for the New Zealand region (146 degrees E-165 degrees W, 60 degrees S-25 degrees S), combining altimetry data from ERS-1 and Geosat Geodetic Missions, as well as available shipborne gravity and echo sounding data. Currently, the lithospheric component of the model is principally applicable to thinly sedimented oceanic basins; however, we have attempted, though with only partial success, to compensate for regional crustal variations. The upper part of the oceanic lithosphere has an elastic behavior related to a half-space cooling model and flexing under seafloor relief load. Using least squares theory, the topographic solution is derived as a linear combination of altimetry and in situ measurements with adjusted coefficients. These coefficients are iteratively fitted using nonlinear operators between bathymetry and altimetry-derived gravity anomalies assuming their error distributions are Gaussian. The theory enables sparse in situ data to be included in the inversion, such as depth soundings and marine gravity profiles. In comparison with the global model of Smith and Sandwell [1997](hereinafter referred to as SS97); the RW99 predicted topography is constrained by over threefold more shipborne soundings data and the inclusion of shipborne gravity data. Three strategies are used to validate the RW99 model. Compared to the root-mean-square (rms) error of 310 m of the SS97 model, final residual differences for the RW99 model are within the range of 104-250 m. These component errors are the result of uncertainties of model parameters, especially the elastic thickness and the relief density, but also the complexity of seafloor topography. In addition, the model inversion does not presently consider gravitational contributions of marine sediments of Variable thickness. C1 Natl Inst Water & Atmospher Res, NIWA, Wellington 3, New Zealand. RP Ramillien, G (reprint author), NOAA, Lab Satellite Altimetry, E-OC2,SSMC3,Room 3620,1315 East West Highway, Silver Spring, MD 20910 USA. EM ramillie@falcon.grdl.noaa.gov; i.wright@niwa.cri.nz RI Wright, Ian/B-9643-2008 OI Wright, Ian/0000-0002-6660-0493 NR 55 TC 11 Z9 13 U1 1 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9313 EI 2169-9356 J9 J GEOPHYS RES-SOL EA JI J. Geophys. Res.-Solid Earth PD JUL 10 PY 2000 VL 105 IS B7 BP 16577 EP 16590 DI 10.1029/2000JB900099 PG 14 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 335TZ UT WOS:000088262000034 ER PT J AU Kulin, S Killian, TC Bergeson, SD Rolston, SL AF Kulin, S Killian, TC Bergeson, SD Rolston, SL TI Plasma oscillations and expansion of an ultracold neutral plasma SO PHYSICAL REVIEW LETTERS LA English DT Article ID STRONGLY COUPLED PLASMAS AB We report the observation of plasma oscillations in an ultracold neutral plasma. With this collective mode we probe the electron density distribution and study the expansion of the plasma as a function of time. For classical plasma conditions, i.e.,weak Coulomb coupling, the expansion is dominated by the pressure of the electron gas and is described by a hydrodynamic model. Discrepancies between the model and observations at low temperature and high density may be due to strong coupling of the electrons. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Bergeson, SD (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RI rolston, steven/L-5175-2013; Bergeson, Scott/L-8959-2013 OI rolston, steven/0000-0003-1671-4190; Bergeson, Scott/0000-0002-3124-9226 NR 19 TC 164 Z9 166 U1 2 U2 14 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD JUL 10 PY 2000 VL 85 IS 2 BP 318 EP 321 DI 10.1103/PhysRevLett.85.318 PG 4 WC Physics, Multidisciplinary SC Physics GA 331ZN UT WOS:000088048700023 ER PT J AU Germer, TA AF Germer, TA TI Measurement of roughness of two interfaces of a dielectric film by scattering ellipsometry SO PHYSICAL REVIEW LETTERS LA English DT Article ID SPECTROSCOPIC IMMERSION ELLIPSOMETRY; LIGHT-SCATTERING; SI(001)/SIO2 INTERFACE; SURFACE MICROROUGHNESS; SUBSURFACE DEFECTS; THERMAL-OXIDATION; THIN-FILMS; DEPENDENCE; SILICON; POLARIZATION AB The polarization of light scattered by oxide films thermally grown on photolithographically generated microrough silicon surfaces was measured as functions of scattering angle, Using the predictions of first-order vector perturbation theory for scattering from interfacial roughness to interpret the results, the roughness of each interface and the correlation function between the two interfaces can be determined. The results show the spatial frequency dependence of the SiO2/Si interface smoothening. C1 NIST, Opt Technol Div, Gaithersburg, MD 20899 USA. RP NIST, Opt Technol Div, Gaithersburg, MD 20899 USA. NR 30 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 0031-9007 EI 1079-7114 J9 PHYS REV LETT JI Phys. Rev. Lett. PD JUL 10 PY 2000 VL 85 IS 2 BP 349 EP 352 DI 10.1103/PhysRevLett.85.349 PG 4 WC Physics, Multidisciplinary SC Physics GA 331ZN UT WOS:000088048700031 ER PT J AU Reid, JP Loomis, RA Leone, SR AF Reid, JP Loomis, RA Leone, SR TI The effect of parent zero-point motion on the ND2 ((A)over-tilde) rotational state distribution in the 193.3 nm photolysis of ND3 SO CHEMICAL PHYSICS LETTERS LA English DT Article ID SELECTIVE PHOTODISSOCIATION DYNAMICS; AMMONIA MOLECULES; ABSORPTION-SPECTRUM; NH3; TRANSITION; NH2D; NHD2; H-2 AB The vibrational and rotational product-state distributions of ND2((A) over tilde (2)A(1)) has been probed following the photodissociation of ND3 at 193.3 nm by time-resolved Fourier Transform infrared emission spectroscopy. The dynamics of the bond cleavage are inferred from the product state distributions by comparison with an earlier study of the photodissociation of NH3. The degree of excitation about the minor rotational b/c-axes of the product is attributed to the amount of zero-point energy of the parent molecule in the v(4), H-N-H (D-N-D) scissors bending coordinate of the NH3/ND3((A) over tilde) predissociative state. A bimodal ND2((A) over tilde(2)A(1)) distribution is observed for rotation about the primary a-axis, analogous to the NH, fragment formed in the photodissociation of NH3. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Natl Inst Stand & Technol, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. Univ Colorado, Dept Chem & Biochem, Boulder, CO 80309 USA. RP Leone, SR (reprint author), Natl Inst Stand & Technol, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. RI Reid, Jonathan/D-9411-2013 NR 20 TC 19 Z9 19 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2614 J9 CHEM PHYS LETT JI Chem. Phys. Lett. PD JUL 7 PY 2000 VL 324 IS 4 BP 240 EP 248 DI 10.1016/S0009-2614(00)00605-9 PG 9 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 332AV UT WOS:000088051600002 ER PT J AU Burden, DL Kasianowicz, JJ AF Burden, DL Kasianowicz, JJ TI Diffusion bias and photophysical dynamics of single molecules in unsupported lipid bilayer membranes probed with confocal microscopy SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Letter ID FLUORESCENCE CORRELATION SPECTROSCOPY; ROOM-TEMPERATURE; FLUCTUATIONS; ABSORPTION AB We use scanning confocal fluorescence microscopy to study the dynamic properties of single fluorescent lipid molecules in unsupported planar bilayers. Specifically, we characterize the emission saturation and diffusive behavior of lipids that have been covalently modified at various locations. By analyzing the time interval between fluorescent bursts, we observe a large deviation from theoretical prediction that indicates a substantial 2D diffusion bias. Interestingly, a correlation between the emission saturation and the power dependency of the deviation suggests that the resonantly enhanced polarizability of the fluorescent label plays a role in the biasing mechanism. Incorporation of the measured fluorescence rate constant into a model for particle escape from a shallow potential well indicates that the well depth is approximate to kT. These results are in agreement with the calculable laser/membrane interaction potential and are consistent with previous reports concerning diffusion biases in free solution caused by weak optical traps. C1 Natl Inst Stand & Technol, Div Biotechnol, Gaithersburg, MD 20899 USA. RP Burden, DL (reprint author), Natl Inst Stand & Technol, Div Biotechnol, Gaithersburg, MD 20899 USA. NR 25 TC 10 Z9 10 U1 0 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 JUL 6 PY 2000 VL 104 IS 26 BP 6103 EP 6107 DI 10.1021/jp0008546 PG 5 WC Chemistry, Physical SC Chemistry GA 332CZ UT WOS:000088057100004 ER PT J AU Mills, KL Gomaa, H AF Mills, KL Gomaa, H TI A knowledge-based method for inferring semantic concepts from visual models of system behavior SO ACM TRANSACTIONS ON SOFTWARE ENGINEERING AND METHODOLOGY LA English DT Article AB Software designers use visual models, such as data flow/control flow diagrams or object collaboration diagrams, to express system behavior in a form that can be understood easily by users and by programmers, and from which designers can generate a software architecture. The research described in this paper is motivated by a desire to provide an automated designer's assistant that can generate software architectures for concurrent systems directly from behavioral models expressed visually as flow diagrams. To achieve this goal, an automated designer's assistant must be capable of interpreting flow diagrams in semantic, rather than syntactic, terms. While semantic concepts can be attached manually to diagrams using labels, such as stereotypes in the Unified Modeling Language (UML), this paper considers the possibility of providing automated assistance to infer appropriate tags for symbols on a flow diagram. The approach relies upon constructing an underlying metamodel that defines semantic concepts based upon (1) syntactic relationships among visual symbols and (2) inheritance relationships among semantic concepts. Given such a metamodel, a rule-based inference engine can, in many situations, infer the presence of semantic concepts on a flow diagram, and can tag symbols accordingly. Further, an object-oriented query system can compare semantic tags on diagram instances for conformance with their definition in the metamodel. To illustrate the approach, the paper describes a metamodel for data flow/control flow diagrams used in the context of a specific software modeling method, Concurrent Object-Based Real-time Analysis (COBRA). The metamodel is implemented using an expert-system shell, CLIPS V6.0, which integrates an object-oriented language with a rule-based inference engine. The paper applies the implemented metamodel to design software for an automobile cruise-control system and provides an evaluation of the approach based upon results from four case studies. For the case studies, the implemented metamodel recognized, automatically and correctly, the existence of 86% of all COBRA semantic concepts within the flow diagrams. Varying degrees of human assistance were used to correctly identify the remaining semantic concepts within the diagrams: in two percent of the cases the implemented metamodel reached tentative classifications that a designer was asked to confirm or override; in four percent of the cases a designer was asked to provide additional information before a concept was classified; in the remaining eight percent of the cases the designer was asked to identify the concept. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. George Mason Univ, Dept Informat & Software Engn, Fairfax, VA 22030 USA. RP Mills, KL (reprint author), Natl Inst Stand & Technol, 100 Bur Dr,Bldg 820,Mail Stop 8920, Gaithersburg, MD 20899 USA. EM kmills@nist.gov; hgomaa@gmu.edu NR 37 TC 5 Z9 5 U1 4 U2 5 PU ASSOC COMPUTING MACHINERY PI NEW YORK PA 2 PENN PLAZA, STE 701, NEW YORK, NY 10121-0701 USA SN 1049-331X EI 1557-7392 J9 ACM T SOFTW ENG METH JI ACM Trans. Softw. Eng. Methodol. PD JUL PY 2000 VL 9 IS 3 BP 306 EP 337 DI 10.1145/352591.352594 PG 32 WC Computer Science, Software Engineering SC Computer Science GA 366JQ UT WOS:000090002600003 ER PT J AU Thomson, DS Schein, ME Murphy, DM AF Thomson, DS Schein, ME Murphy, DM TI Particle analysis by laser mass spectrometry WB-57F instrument overview SO AEROSOL SCIENCE AND TECHNOLOGY LA English DT Article ID AEROSOLS; INLET AB Recently, a second version of the Particle Analysis by Laser Mass Spectroscopy (PALMS) instrument was constructed to fly in the nose of a WB-57F research aircraft, allowing it to make in-situ measurements of stratospheric aerosols. We present here the technical aspects of the design and construction of the PALMS aircraft instrument. These include the development of a robust and complex data acquisition and control software program, a stable optical system with in-flight correction, the mechanical packaging required for in-flight operation, a shrouded inlet designed for optimal particle sampling, and custom and commercial electronics. We also present a brief review of the performance of the PALMS instrument during its first deployment in the WB-57F. C1 Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. NOAA, Aeron Lab, Boulder, CO 80303 USA. RP Thomson, DS (reprint author), Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. RI Murphy, Daniel/J-4357-2012 OI Murphy, Daniel/0000-0002-8091-7235 NR 9 TC 74 Z9 77 U1 1 U2 9 PU TAYLOR & FRANCIS INC PI PHILADELPHIA PA 325 CHESTNUT ST, SUITE 800, PHILADELPHIA, PA 19106 USA SN 0278-6826 J9 AEROSOL SCI TECH JI Aerosol Sci. Technol. PD JUL-AUG PY 2000 VL 33 IS 1-2 BP 153 EP 169 DI 10.1080/027868200410903 PG 17 WC Engineering, Chemical; Engineering, Mechanical; Environmental Sciences; Meteorology & Atmospheric Sciences SC Engineering; Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA 330HM UT WOS:000087956800011 ER PT J AU Auvinen, A Linet, MS Hatch, EE Kleinerman, RA Robison, LL Kaune, WT Misakian, M Niwa, S Wacholder, S Tarone, RE AF Auvinen, A Linet, MS Hatch, EE Kleinerman, RA Robison, LL Kaune, WT Misakian, M Niwa, S Wacholder, S Tarone, RE TI Extremely low-frequency magnetic fields and childhood acute lymphoblastic leukemia: An exploratory analysis of alternative exposure metrics SO AMERICAN JOURNAL OF EPIDEMIOLOGY LA English DT Article DE case-control studies; child; electromagnetic fields; environmental exposure; leukemia, lymphocytic, acute ID RESIDENTIAL EXPOSURE; CHILDREN; CANCER; RISK; APPLIANCES; INDEXES; CANADA; TUMORS; 50-HZ AB Data collected by the National Cancer institute-Children's Cancer Group were utilized to explore various metrics of magnetic field levels and risk of acute lymphoblastic leukemia (ALL) in children. Cases were aged 0-14 years, were diagnosed with ALL during 1989-1993, were registered with the Children's Cancer Group, and resided in one home for at least 70 percent of the 5 years immediately prior to diagnosis. Controls were identified by using random digit dialing and met the same residential requirements. With 30-second ("spot") measurements and components of the 24-hour measurement obtained in the subject's bedroom, metrics evaluated included measures of central tendency, peak exposures, threshold values, and measures of short-term temporal variability. Measures of central tendency and the threshold measures showed good-to-high correlation, but these metrics correlated less well with the others. Small increases in risk (ranging from 1.02 to 1.69 for subjects in the highest exposure category) were associated with some measures of central tendency, but peak exposures, threshold values, measures of short-term variability, and spot measurements demonstrated little association with risk of childhood ALL. In general, risk estimates were slightly higher for the nighttime (10 p.m.-6 a.m.) interval than for the corresponding 24-hour period. C1 NCI, Div Canc Epidemiol & Genet, Radiat Epidemiol Branch, Bethesda, MD 20892 USA. Radiat & Nucl Safety Author, Helsinki, Finland. Childrens Canc Grp, Arcadia, CA USA. EM Factors, Richland, WA USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Westat Inc, Rockville, MD USA. RP Linet, MS (reprint author), NCI, Div Canc Epidemiol & Genet, Radiat Epidemiol Branch, 6120 Execut Blvd,Room EPS 7054, Bethesda, MD 20892 USA. OI Kleinerman, Ruth/0000-0001-7415-2478; Auvinen, Anssi/0000-0003-1125-4818 NR 38 TC 24 Z9 25 U1 0 U2 0 PU OXFORD UNIV PRESS INC PI CARY PA JOURNALS DEPT, 2001 EVANS RD, CARY, NC 27513 USA SN 0002-9262 J9 AM J EPIDEMIOL JI Am. J. Epidemiol. PD JUL 1 PY 2000 VL 152 IS 1 BP 20 EP 31 DI 10.1093/aje/152.1.20 PG 12 WC Public, Environmental & Occupational Health SC Public, Environmental & Occupational Health GA 331TV UT WOS:000088035500005 PM 10901326 ER PT J AU Dimeo, RM AF Dimeo, RM TI Fourier transform solution to the semi-infinite resistance ladder SO AMERICAN JOURNAL OF PHYSICS LA English DT Article C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Dimeo, RM (reprint author), Natl Inst Stand & Technol, 100 Bur Dr,Stop 8562, Gaithersburg, MD 20899 USA. NR 3 TC 1 Z9 1 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0002-9505 J9 AM J PHYS JI Am. J. Phys. PD JUL PY 2000 VL 68 IS 7 BP 669 EP 670 DI 10.1119/1.19508 PG 2 WC Education, Scientific Disciplines; Physics, Multidisciplinary SC Education & Educational Research; Physics GA 326VF UT WOS:000087757100010 ER PT J AU Van Zandt, TE AF Van Zandt, TE TI A brief history of the development of wind-profiling or MST radars SO ANNALES GEOPHYSICAE-ATMOSPHERES HYDROSPHERES AND SPACE SCIENCES LA English DT Article DE meteorology and atmospheric dynamics; instruments and techniques; radio science; remote sensing; instruments and techniques ID JICAMARCA VHF RADAR; PHASED-ARRAY SYSTEM; CLEAR-AIR; DOPPLER RADAR; MU RADAR; BOUNDARY-LAYER; VERTICAL WIND; VELOCITIES; ATMOSPHERE; ANTENNA AB The history of the development of the wind-profiling or MST radar technique is reviewed from its inception in the late 1960s to the present. Extensions of the technique by the development of boundary-layer radars and the radio-acoustic sounding system (RASS) technique to measure temperature are documented. Applications are described briefly, particularly practical applications to weather forecasting, with data from networks of radars, and scientific applications to the study of rapidly varying atmospheric phenomena such as gravity waves and turbulence. C1 NOAA, Aeron Lab, Boulder, CO 80303 USA. RP Van Zandt, TE (reprint author), NOAA, Aeron Lab, 325 Broadway, Boulder, CO 80303 USA. NR 61 TC 11 Z9 11 U1 0 U2 8 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0992-7689 J9 ANN GEOPHYS-ATM HYDR JI Ann. Geophys.-Atmos. Hydrospheres Space Sci. PD JUL PY 2000 VL 18 IS 7 BP 740 EP 749 DI 10.1007/s005850000220 PG 10 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA 338BB UT WOS:000088397300003 ER PT J AU Fuller-Rowell, TJ Codrescu, MC Wilkinson, P AF Fuller-Rowell, TJ Codrescu, MC Wilkinson, P TI Quantitative modeling of the ionospheric response to geomagnetic activity SO ANNALES GEOPHYSICAE-ATMOSPHERES HYDROSPHERES AND SPACE SCIENCES LA English DT Article DE ionosphere; ionospheric disturbances; mid-latitude ionosphere; modeling and forecasting ID ANTARCTIC F-REGION; THERMOSPHERIC COMPOSITION; MIDDLE LATITUDES; STORMS; ELECTRODYNAMICS; PATTERNS; LAYER AB A physical model of the coupled thermosphere and ionosphere has been used to determine the accuracy of model predictions of the ionospheric response to geomagnetic activity, and assess our understanding of the physical processes. The physical model is driven by empirical descriptions of the high-latitude electric field and auroral precipitation, as measures of the strength of the magnetospheric sources of energy and momentum to the upper atmosphere. Both sources are keyed to the time-dependent TIROS/NOAA auroral power index. The output of the model is the departure of the ionospheric F region from the normal climatological mean. A. 50-day interval towards the end of 1997 has been simulated with the model for two cases. The first simulation uses only the electric fields and auroral forcing from the empirical models, and the second has an additional source of random electric field variability. In both cases, output from the physical model is compared with F-region data from ionosonde stations. Quantitative model/data comparisons have been performed to move beyond the conventional "visual" scientific assessment, in order to determine the value of the predictions for operational use. For this study, the ionosphere at two ionosonde stations has been studied in depth, one each from the not-them and southern midlatitudes. The model clearly captures the seasonal dependence in the ionospheric response to geomagnetic activity at mid-latitude: reproducing the tendency for decreased ion density in the summer hemisphere and increased densities in winter. In contrast to the "visual" success of the model, the detailed quantitative comparisons, which are necessary for space weather applications, are less impressive. The accuracy, or value, of the model has been quantified by evaluating the daily standard deviation, the root-mean-square error, and the correlation coefficient between the data and model predictions. The modeled quiet-time variability, or standard deviation, and the increases during geomagnetic activity, agree well with the data in winter, but is low in summer. The RMS error of the physical model is about the same as the IRT. empirical model during quiet times. During the storm events the RLMS error of the model improves on IRI, but there are occasionally false-alarms. Using unsmoothed data over the full interval, the correlation coefficients between the model and data are low, between 0.3 and 0.4. Isolating the storm intervals increases the correlation to between 0.43 and 0.56, and by smoothing the data the values increases up to 0.65. The study illustrates the substantial difference between scientific success and a demonstration of value for space weather applications. C1 NOAA, Space Environm Ctr, Boulder, CO 80303 USA. Univ Colorado, CIRES, Boulder, CO 80303 USA. Ionospher Predict Serv, Sydney, NSW, Australia. RP NOAA, Space Environm Ctr, Boulder, CO 80303 USA. EM tjfr@sec.noaa.gov NR 25 TC 62 Z9 63 U1 0 U2 2 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0992-7689 J9 ANN GEOPHYS-ATM HYDR JI Ann. Geophys.-Atmos. Hydrospheres Space Sci. PD JUL PY 2000 VL 18 IS 7 BP 766 EP 781 DI 10.1007/s00585-000-0766-7 PG 16 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA 338BB UT WOS:000088397300005 ER PT J AU Bakulin, AS Durbin, SM Jach, T Pedulla, J AF Bakulin, AS Durbin, SM Jach, T Pedulla, J TI Fast imaging of hard x rays with a laboratory microscope SO APPLIED OPTICS LA English DT Article ID SYNCHROTRON-RADIATION; MULTILAYER MIRRORS; MATERIALS SCIENCE; MICROTOMOGRAPHY; MICROPROBE; REFLECTIVITY; OPTICS AB An improved x-ray microscope with a fully electronic CCD detector system has been constructed that allows improved laboratory-based microstructural investigations of materials with hard x rays. It uses the Kirkpatrick-Baez multilayer mirror design to form an image that has a demonstrated resolution of 4 mu m at 8 keV (Cu K-alpha radiation). This microscope performs well with standard sealed-tube laboratory x-ray sources, producing digital images with 20-s exposure times for a 5-mu m Au grid (a thickness of two absorption lengths). (C) 2000 Optical Society of America OCIS codes: 340.0340, 340.7440, 340.7460. C1 Purdue Univ, Dept Phys, W Lafayette, IN 47907 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. J Pedulla Associates, Silver Spring, MD 20906 USA. RP Bakulin, AS (reprint author), Purdue Univ, Dept Phys, W Lafayette, IN 47907 USA. EM durbin@physics.purdue.edu NR 21 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 JUL 1 PY 2000 VL 39 IS 19 BP 3333 EP 3337 DI 10.1364/AO.39.003333 PG 5 WC Optics SC Optics GA 331YE UT WOS:000088045600020 PM 18349901 ER PT J AU Sugiura, SH Babbitt, JK Dong, FM Hardy, RW AF Sugiura, SH Babbitt, JK Dong, FM Hardy, RW TI Utilization of fish and animal by by-product meals in low-pollution feeds for rainbow trout Oncorhynchus mykiss (Walbaum) SO AQUACULTURE RESEARCH LA English DT Article ID SALMON SALMO-SALAR; PROTEIN DIGESTIBILITY; BONE-MEAL; AVAILABILITY; MINERALS; DIETS; ZINC; BIOAVAILABILITY; INGREDIENTS; PHOSPHATE AB The apparent digestibilities (availabilities) of dry matter, protein, phosphorus and selected minerals in fish and animal by-products were determined using rainbow trout Oncorhynchus mykiss (Walbaum). Blood meal (ring-dried), feather meal and deboned fish meal had relatively high concentrations of protein, low concentrations of phosphorus and many minerals, and high digestibilities (availabilities) of these nutrients. Other animal byproducts, however, had high concentrations of minerals, including phosphorus, which are associated with the bone fraction. Availabilities of manganese and zinc in the diet were reduced by the inclusion of high-ash animal by-products in the diet, whereas availabilities of potassium, sodium and copper were relatively unaffected. Dietary concentrations of bone minerals (calcium, phosphorus) and ash were inversely correlated with availabilities (% of intake) of most minerals except copper in the diet. Also, dietary concentrations of bone minerals correlated inversely with the net absorption (mg g(-1) diet) of zinc, manganese and magnesium in the diet. When rainbow trout were fed diets containing incremental concentrations of fish bones, the apparent availabilities of phosphorus, calcium, magnesium and iron decreased as fish bone content in the diet increased. Reducing the bone fraction of high-ash (high-phosphorus) by-product meals is therefore an essential approach to using such ingredients in low-pollution fish feeds. C1 Univ Idaho, Hagerman Fish Culture Expt Stn, Hagerman, ID 83332 USA. Natl Marine Fisheries Serv, Utilizat Div, Seattle, WA USA. Univ Washington, Sch Fisheries, Seattle, WA 98195 USA. RP Hardy, RW (reprint author), Univ Idaho, Hagerman Fish Culture Expt Stn, 3059F Natl Fish Hatchery Rd, Hagerman, ID 83332 USA. NR 28 TC 52 Z9 57 U1 1 U2 12 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD OX2 0NE, OXON, ENGLAND SN 1355-557X J9 AQUAC RES JI Aquac. Res. PD JUL PY 2000 VL 31 IS 7 BP 585 EP 593 DI 10.1046/j.1365-2109.2000.00476.x PG 9 WC Fisheries SC Fisheries GA 335WN UT WOS:000088267900005 ER PT J AU Fenves, SJ Rivard, H Gomez, N AF Fenves, SJ Rivard, H Gomez, N TI SEED-Config: a tool for conceptual structural design in a collaborative building design environment SO ARTIFICIAL INTELLIGENCE IN ENGINEERING LA English DT Article DE design environment; conceptual design; building design; structural design; collaborative design; case-based reasoning; information model; knowledge representation; classification and indexing; object-oriented programming ID SYSTEM; MODEL AB SEED-Config is a design environment intended to assist structural designers in collaboratively exploring and extending the design buildings. Its purpose is to help designers in rapidly synthesizing alternative structural design solutions at the conceptual level to the point where the structural concept is supportive of the overall design and possible conflicts are explored and resolved. The SEED-Config prototype consists of four subsystems. The Design Information Repository is built upon an information model that exploits the hierarchical nature of building descriptions to represent design information. It can save an overall design or parts of a design to a case library, thus supporting case-based reasoning. The Design Knowledge Manager allows for the browsing, editing, selecting and applying of technology nodes which encapsulate structural design knowledge. The Classification Reference Manager allows for the definition, management, inference and querying of classifications which are used to classify and index design solutions as they are generated. The Geometric Modeler reasons about topology and geometry. (C) 2000 Elsevier Science Ltd. All rights reserved. C1 Concordia Univ, Ctr Bldg Studies, Dept Bldg Civil & Environm Engn, Montreal, PQ H3G 1M8, Canada. NIST, Gaithersburg, MD 20899 USA. Florida Int Univ, Dept Civil & Environm Engn, Miami, FL 33199 USA. RP Rivard, H (reprint author), Concordia Univ, Ctr Bldg Studies, Dept Bldg Civil & Environm Engn, 1455 Maisonneuve Blvd W, Montreal, PQ H3G 1M8, Canada. NR 28 TC 25 Z9 26 U1 0 U2 2 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0954-1810 J9 ARTIF INTELL ENG JI Artif. Intell. Eng. PD JUL PY 2000 VL 14 IS 3 BP 233 EP 247 DI 10.1016/S0954-1810(00)00018-2 PG 15 WC Computer Science, Artificial Intelligence; Engineering, Multidisciplinary SC Computer Science; Engineering GA 383YA UT WOS:000165911200004 ER PT J AU Leto, G Pagano, I Linsky, JL Rodono, M Umana, G AF Leto, G Pagano, I Linsky, JL Rodono, M Umana, G TI VLA observation of dMe stars SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE stars : activity; stars : coronae; stars : late-type; stars : variables : general; radio continuum : stars ID RADIO-EMISSION; MAIN-SEQUENCE; DWARF STARS; FLARE STARS; CATALOG; CORONAE AB We present new VLA radio observations of a sample of dMe stars in X, U, K, and Q bands (from 8.4 to 43 GHz) obtained during an observing campaign in 1996 April-June. The aim of the project was to determine the spectral energy distributions of late-type dwarf flare stars to investigate the possible existence of an inversion of the spectrum slope at frequencies higher than 8 GHz. We also tried to constrain the possible emission mechanism at radio frequencies. We have detections in X band (8.4 GHz), for three sources (UV Get, V 1054 Oph, and EV Lac), while all of our other measurements are upper limits. We discuss how the weak radio emission of some sources (e.g. AU Mic) and the coronal plasma properties deduced from X-ray observations constrain the coronal magnetic field properties. C1 Osserv Astrofis Catania, I-95123 Catania, Italy. Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. Natl Inst Stand & Technol, Boulder, CO 80309 USA. Univ Catania, Dipartimento Fis & Astron, I-95123 Catania, Italy. CNR, Ist Radioastron, I-96017 Noto, SR, Italy. RP Osserv Astrofis Catania, Via S Sofia 78, I-95123 Catania, Italy. EM gleto@ct.astro.it RI Leto, Giuseppe/N-3355-2015; Pagano, Isabella/I-6934-2015 OI Leto, Giuseppe/0000-0002-0040-5011; Pagano, Isabella/0000-0001-9573-4928 NR 32 TC 18 Z9 18 U1 0 U2 0 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 1432-0746 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD JUL PY 2000 VL 359 IS 3 BP 1035 EP 1041 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 341JZ UT WOS:000088588400023 ER PT J AU Wood, BE Linsky, JL Zank, GP AF Wood, BE Linsky, JL Zank, GP TI Heliospheric, astrospheric, and interstellar Ly alpha absorption toward 36 ophiuchi SO ASTROPHYSICAL JOURNAL LA English DT Article DE ISM : atoms; solar wind; stars : individual (36 Ophiuchi A); stars : winds, outflows; ultraviolet : ISM ID SOLAR-WIND INTERACTION; LOCAL CLOUD; HYDROGEN ABSORPTION; GHRS OBSERVATIONS; D/H RATIO; HST-GHRS; SIRIUS-A; GAS; IONIZATION; CENTAURI AB We use high-resolution UV spectra taken by the Space Telescope Imaging Spectrograph instrument on board the Hubble Space Telescope to study the 5.5 pc line of sight to the K0 V star 36 Oph A. The one interstellar component detected for this line of sight has a velocity inconsistent with the local interstellar cloud (LIC) flow vector but consistent with the flow vector of the so-called G cloud, a very nearby warm cloud in the Galactic center direction. From our data, we measure the following values for the interstellar temperature, nonthermal velocity, H I column density, and D/H value: T = 5900 +/- 500 K, xi = 2.2 +/- 0.2 km s(-1), log N-H = 17.85 +/- 0.15, and D/H = (1.5 +/- 0.5) x 10(-5). The temperature of the G cloud is somewhat lower than that of the LIC, and Mg and Fe depletions are also lower, but the D/H value appears to be the same. Based on upper limits for the LIC absorption, we estimate the distance to the edge of the LIC to be d(edge) < 0.19 pc, which the Sun will reach in t(edge) < 7400 yr. The H I Ly alpha absorption line has properties inconsistent with those of the other absorption lines, indicating the presence of one or more absorption components not seen in the other lines. We present evidence that hot neutral hydrogen local to both the Sun and the star is responsible for the excess Lya absorption. This hot H I is created by the interaction between the ISM and the winds of the Sun and 36 Oph A. The observed line of sight lies only 12 degrees from the upwind direction of the LIC flow vector, where hydrodynamic models of the heliosphere suggest that heliospheric H I. absorption should be particularly prominent. The properties of the heliospheric absorption (T = 38,000 +/- 8000 K and log N-H = 14.6 +/- 0.3) are consistent with previous measurements of this absorption for the alpha Cen line of sight 52 degrees from the upwind direction. C1 Univ Colorado, JILA, Boulder, CO 80309 USA. NIST, Boulder, CO 80309 USA. Univ Delaware, Bartol Res Inst, Newark, DE 19716 USA. RP Wood, BE (reprint author), Univ Colorado, JILA, Boulder, CO 80309 USA. NR 32 TC 76 Z9 77 U1 0 U2 1 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 JUL 1 PY 2000 VL 537 IS 1 BP 304 EP 311 DI 10.1086/309026 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 337PN UT WOS:000088371000027 ER PT J AU Hils, D Bender, PL AF Hils, D Bender, PL TI Gravitational radiation from helium cataclysmics SO ASTROPHYSICAL JOURNAL LA English DT Article DE binaries : close; gravitation; novae, cataclysmic variables; white dwarfs ID SEMIDETACHED BINARIES; CLOSE BINARIES; WHITE-DWARFS; STARS; MASS; EVOLUTION; SECONDARIES; SUPERNOVAE; PERIOD AB For a gravitational wave antenna in space, radiation from very large numbers of galactic binaries will be present in the observable frequency band from roughly 10(-5) Hz to 1 Hz. At frequencies above about 3 mHz, signals from thousands of compact binaries will be resolvable in both frequency and direction. At lower frequencies, there will be confusion noise from having more than one binary per frequency resolution bin, even with a year or more of data. In this paper, we extend previous discussions of the galactic binaries to include an improved estimate of the contributions to the confusion noise from AM CVn binaries and their probable progenitors, which we refer to as helium cataclysmics. We find only a slight increase in the confusion noise below about 3 mHz, and essentially no increase at higher frequencies. C1 Univ Colorado, JILA, Boulder, CO 80309 USA. Natl Inst Stand & Technol, Boulder, CO 80309 USA. RP Hils, D (reprint author), Univ Colorado, JILA, Boulder, CO 80309 USA. NR 29 TC 48 Z9 48 U1 0 U2 1 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 JUL 1 PY 2000 VL 537 IS 1 BP 334 EP 341 DI 10.1086/308997 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 337PN UT WOS:000088371000031 ER PT J AU Valenti, JA Johns-Krull, CM Linsky, JL AF Valenti, JA Johns-Krull, CM Linsky, JL TI An IUE atlas of pre-main-sequence stars. I. Co-added final archive spectra from the SWP camera SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article DE accretion, accretion disks; atlases; stars : pre-main sequence; ultraviolet : stars ID HERBIG AE/BE STARS; T-TAURI STARS; AB-AURIGAE; AE STARS; MASS STARS; BP TAURI; X-RAY; MG-II; ULTRAVIOLET; ACCRETION AB We have identified 50 T Tauri stars (TTS) and 74 Herbig Ae/Be (HAEBE) stars observed in the IUE short-wavelength bandpass (1150-1980 Angstrom). Each low-resolution (R similar to 6 Angstrom) spectrum was visually inspected for source contamination and data quality, and then all good spectra were combined to form a single time-averaged spectrum for each star. Use of IUE Final Archive spectra processed with NEWSIPS reduces fixed pattern noise in individual spectra, allowing significant signal-to-noise ratio gains in our co-added spectra. For the TTS observed by IUE, we measured fluxes and uncertainties for 17 spectral features, including two continuum windows and four fluoresced H-2 complexes. Thirteen of the 32 accreting TTS observed by IUE have detectable H-2 emission, which until now had been reported only for T Tau. Using an empirical correlation between H-2 and C IV line flux, we show that lack of sensitivity can account for practically all nondetections, suggesting that H-2 fluorescence may be intrinsically strong in all accreting TTS systems. Comparison of IUE and GHRS spectra of T Tau show extended emission primarily, but not exclusively, in lines of H-2. We also fit reddened main-sequence templates to 72 HAEBE stars, determining extinction and checking spectral types. Several of the HAEBE stars could not be fitted well or yielded implausibly low extinctions, suggesting the presence of a minority emission component hotter than the stellar photosphere, perhaps caused by white dwarf companions or heating in accretion shocks. We identified broad wavelength intervals in the far-UV that contain circumstellar absorption features ubiquitous in B5-A4 HAEBE stars, declining in prominence for earlier spectral types, perhaps caused by increasing ionization of metal resonance lines. For 61 HAEBE stars, we measured or set upper limits on a depth index that characterizes the strength of circumstellar absorption and compared this depth index with published IR properties. C1 Space Telescope Sci Inst, Baltimore, MD 21218 USA. Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. NIST, Boulder, CO 80309 USA. RP Valenti, JA (reprint author), Space Telescope Sci Inst, 3700 San Martin Dr, Baltimore, MD 21218 USA. NR 50 TC 104 Z9 104 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0067-0049 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD JUL PY 2000 VL 129 IS 1 BP 399 EP 420 DI 10.1086/313408 PG 22 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 365MC UT WOS:000089954200018 ER PT J AU Mayhew, MP Reipa, V Holden, MJ Vilker, VL AF Mayhew, MP Reipa, V Holden, MJ Vilker, VL TI Improving the cytochrome P450 enzyme system for electrode-driven biocatalysis of styrene epoxidation SO BIOTECHNOLOGY PROGRESS LA English DT Article ID P-450CAM; CAMPHOR; 5-MONOOXYGENASE; MUTAGENESIS; PUTIDAREDOXIN; HYDROXYLATION; DEGRADATION; METABOLISM; REDUCTION; SUBSTRATE AB Cytochrome P450 enzymes catalyze a vast array of oxidative and reductive biotransformations that are potentially useful for industrial and pharmaceutical syntheses. Factors such as cofactor utilization and slow reaction rates for nonnatural substrates limit their large-scale usefulness. This paper reports several improvements that make the cytochrome P450cam enzyme system more practical for the epoxidation of styrene. NADH coupling was increased from 14 to 54 mol %, and product turnover rate was increased from 8 to 70 min(-1) by introducing the Y96F mutation to P450cam. Styrene and styrene oxide mass balance determinations showed different product profiles at low and high styrene conversion levels. For styrene conversion less than about 25 mol %, the stoichiometry between styrene consumption and styrene oxide formation was 1:1. At high styrene conversion, a second doubly oxidized product, alpha-hydroxyacetophenone, was formed. This was also the exclusive product when Y96F P450cam acted on racemic, commercially available styrene oxide. The cl-hydroxyacetophenone product was suppressed in reactions where styrene was present at saturating concentrations. Finally, styrene epoxidation was carried out in an electroenzymatic reactor. In this scheme, the costly NADH cofactor and one of the three proteins (putidaredoxin reductase) are eliminated from the Y96F P450cam enzyme system. C1 Natl Inst Stand & Technol, Div Biotechnol, Gaithersburg, MD 20899 USA. RP Vilker, VL (reprint author), Natl Inst Stand & Technol, Div Biotechnol, Gaithersburg, MD 20899 USA. NR 29 TC 47 Z9 47 U1 0 U2 8 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 8756-7938 J9 BIOTECHNOL PROGR JI Biotechnol. Prog. PD JUL-AUG PY 2000 VL 16 IS 4 BP 610 EP 616 DI 10.1021/bp000067q PG 7 WC Biotechnology & Applied Microbiology; Food Science & Technology SC Biotechnology & Applied Microbiology; Food Science & Technology GA 343PF UT WOS:000088710200014 PM 10933836 ER PT J AU Gall, R Shapiro, M AF Gall, R Shapiro, M TI The influence of Carl-Gustaf Rossby on mesoscale weather prediction and an outlook for the future SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article ID VERTICAL COORDINATE; MODEL AB This article presents an overview of the advances in mesoscale prediction from the time of Rossby to the present and an outlook for the future. The first part traces the evolution of research and forecasting based upon the conservation of certain properties on isentropic coordinates. It begins with Rossby's use of these properties to identify and follow air masses and concludes with current use of the isentropic/potential vorticity framework to define air motions and to describe cyclones, fronts, and associated mesoscale precipitation systems, as well as numerical weather prediction in isentropic coordinates. Highlights of this historical research on mesoscale prediction are presented. Regarding future advances in mesoscale observations and prediction, the authors suggest that, for the next decade, the prospects for global mesoscale datasets are not encouraging: Researchers will have to be content with datasets with resolutions considerably below the resolution that is likely to be available from operational numerical weather prediction models. The exceptions will be confined to limited continental regions. In spite of this, useful forecasts of mesoscale phenomena out to several days should be possible in certain situations, not only in the limited regions where initial states can be defined at high resolution, but elsewhere, provided that the synoptic-scale systems can be initially well defined and, subsequently, well forecast. C1 Natl Ctr Atmospher Res, MMM, Boulder, CO 80307 USA. NOAA, Environm Technol Lab, Boulder, CO USA. RP Gall, R (reprint author), Natl Ctr Atmospher Res, MMM, Pob 3000, Boulder, CO 80307 USA. NR 37 TC 9 Z9 9 U1 0 U2 1 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 JUL PY 2000 VL 81 IS 7 BP 1507 EP 1523 DI 10.1175/1520-0477(2000)081<1507:TIOCGR>2.3.CO;2 PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 329BY UT WOS:000087887300002 ER PT J AU Takagi, S Liao, H Chow, LC AF Takagi, S Liao, H Chow, LC TI Effect of tooth-bound fluoride on enamel demineralization/remineralization in vitro SO CARIES RESEARCH LA English DT Article DE tooth-bound fluoride; fluorapatite; human enamel; acidulated phosphate fluoride; dicalcium phosphate dihydrate; pH cyclic model ID LESION FORMATION; DENTAL-CARIES; INVITRO; DEMINERALIZATION; INVIVO; REMINERALIZATION; CAHPO4.2H2O; PHOSPHATE; MODEL AB The effect of tooth-bound fluoride (F) on enamel caries formation was investigated under the condition that loosely bound F was essentially absent. Eighteen thin enamel sections, prepared from the lingual or buccal surfaces of extracted human molars, were embedded in acrylic resin with the enamel surfaces exposed, The sections were placed in a pH 7 remineralizing solution (RS; 1.2 mmol/l Ca, 0.72 mmol/l P,30 mmol/l KCI, 50 mmol/l HEPES) for 5 days, and were randomly divided into 3 groups: (1) control group that received no treatment, (2) acidulated phosphate fluoride (APF) group that received 5 cycles of a 4 min treatment with APF gel followed by immersion in the RS for 2 days (RS changed daily) and (3) dicalcium phosphate dihydrate (DCPD) - APF group that received 5 cycles of a 4-min pH 2.1 DCPD-forming solution followed by 4 min APF gel and then placed in the RS for 2 days. After the treatment cycles, the sections were washed in a constant composition F titration system to remove loosely bound F,An in vitro model, which consisted of cycles of de- (6 h) and remineralization (18 h) each day for 5 days, was used to produce caries-like lesions in the specimens. The Delta Z (mineral loss) values, measured by quantitative microradiography, of the lesions formed in the three groups were (mean +/- standard deviation; n = 6) 91.2 +/- 12.3 I-im for the control group, 41.3 +/- 10.1 mu m for the APF group and 21.2 +/- 4.8 mu m for the DCPD-APF group, The same system produced lesions in untreated shark enamel with a mean Delta Z of 4.4 +/- 0.3 mu m (n = 12). One-way fixed-effects ANOVA indicated that mineral loss was significantly different among the different groups (p<0.05). The results showed that enamel resistance to lesion formation increased with increasing tooth-bound F content, Shark enamel was much more resistant to demineralization than human enamel. Copyright (C) 2000 S. Karger AG. Basel. C1 Natl Inst Stand & Technol, Paffenbarger Res Ctr, Amer Dent Assoc Hlth Fdn, Gaithersburg, MD 20899 USA. RP Takagi, S (reprint author), Natl Inst Stand & Technol, Paffenbarger Res Ctr, Amer Dent Assoc Hlth Fdn, Gaithersburg, MD 20899 USA. FU NIDCR NIH HHS [DE05354] NR 36 TC 26 Z9 30 U1 1 U2 4 PU KARGER PI BASEL PA ALLSCHWILERSTRASSE 10, CH-4009 BASEL, SWITZERLAND SN 0008-6568 J9 CARIES RES JI Caries Res. PD JUL-AUG PY 2000 VL 34 IS 4 BP 281 EP 288 DI 10.1159/000016603 PG 8 WC Dentistry, Oral Surgery & Medicine SC Dentistry, Oral Surgery & Medicine GA 326HT UT WOS:000087728300001 PM 10867429 ER PT J AU Bentz, DP AF Bentz, DP TI Influence of silica fume on diffusivity in cement-based materials II. Multi-scale modeling of concrete diffusivity SO CEMENT AND CONCRETE RESEARCH LA English DT Article DE concrete; diffusion; hydration; modeling; silica fume ID INTERFACIAL ZONE; PERFORMANCE; SIMULATION; PASTE AB Based on a set of multi-scale computer models, an equation is developed for predicting the chloride ion diffusivity of concrete as a function of water-to-cement (w/c) ratio, silica fume addition, degree of hydration and aggregate volume fraction. Silica fume influences concrete diffusivity in several ways: (1) densifying the microstructure of the interfacial transition zone (ITZ) regions, (2) reducing the overall (bulk and ITZ) capillary porosity for a fixed degree of cement hydration, and (3) producing a pozzolanic C-S-H gel with a relative diffusivity about 25 times less than that of the C-S-H gel produced from conventional cement hydration. According to the equation and in agreement with results from the literature, silica fume is most efficient for reducing diffusivity in lower w/c ratio concretes (w/c < 0.4). In these systems, for moderate additions of silica fume (e.g., 10%), the reduction in concrete diffusivity may be a factor of 15 or more, which may substantially increase the service life of steel-reinforced concrete exposed in a severe corrosion environment. Published by Elsevier Science Ltd. All rights reserved. C1 Natl Inst Stand & Technol, Bldg & Fire Res Lab, Gaithersburg, MD 20899 USA. RP Bentz, DP (reprint author), Natl Inst Stand & Technol, Bldg & Fire Res Lab, 100 Bur Dr Stop 8621, Gaithersburg, MD 20899 USA. RI Chen, Wei/A-5694-2010 NR 25 TC 58 Z9 61 U1 1 U2 13 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 JUL PY 2000 VL 30 IS 7 BP 1121 EP 1129 DI 10.1016/S0008-8846(00)00263-5 PG 9 WC Construction & Building Technology; Materials Science, Multidisciplinary SC Construction & Building Technology; Materials Science GA 356KQ UT WOS:000089442800014 ER PT J AU Bentz, DP Hansen, KK AF Bentz, DP Hansen, KK TI Preliminary observations of water movement in cement pastes during curing using X-ray absorption SO CEMENT AND CONCRETE RESEARCH LA English DT Article DE cement paste; curing; drying; water movement; X-ray absorption ID CONCRETE AB X-ray absorption and concurrent mass measurements are used in quantifying water movement in 4 to 5 mm thick cement paste specimens with their top surface exposed to drying. Experimental variables examined in this preliminary study include water-to-cement (wic) ratio and open vs. capped samples. Layered specimens (e.g., 0.3 w/c ratio paste over 0.45 wic ratio paste) are also examined to monitor the preferential water movement from less dense (higher wic ratio) paste to denser paste due to capillary forces. For the open samples examined in this study, the initial drying is observed to occur uniformly throughout the thickness of the specimen, as opposed to proceeding as a sharp front progressing inward from the surface exposed to the external environment. In the layered specimens, the higher w/c ratio paste layer is seen to "dry out" first regardless of its location within the composite. The implications of these experimental observations for curing of concrete and application of repair materials are discussed. (C) 2000 Elsevier Science Ltd. All rights reserved. C1 Natl Inst Stand & Technol, Bldg & Fire Res Lab, Gaithersburg, MD 20899 USA. Tech Univ Denmark, DK-2800 Lyngby, Denmark. RP Bentz, DP (reprint author), Natl Inst Stand & Technol, Bldg & Fire Res Lab, 100 Bur Dr Stop 8621, Gaithersburg, MD 20899 USA. RI Chen, Wei/A-5694-2010 NR 13 TC 33 Z9 34 U1 1 U2 6 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 JUL PY 2000 VL 30 IS 7 BP 1157 EP 1168 DI 10.1016/S0008-8846(00)00273-8 PG 12 WC Construction & Building Technology; Materials Science, Multidisciplinary SC Construction & Building Technology; Materials Science GA 356KQ UT WOS:000089442800018 ER PT J AU Gilman, JW Jackson, CL Morgan, AB Harris, R Manias, E Giannelis, EP Wuthenow, M Hilton, D Phillips, SH AF Gilman, JW Jackson, CL Morgan, AB Harris, R Manias, E Giannelis, EP Wuthenow, M Hilton, D Phillips, SH TI Flammability properties of polymer - Layered-silicate nanocomposites. Polypropylene and polystyrene nanocomposites SO CHEMISTRY OF MATERIALS LA English DT Article ID NYLON 6-CLAY HYBRID; MECHANICAL-PROPERTIES; CLAY AB Our continuing study of the mechanism of flammability reduction of polymer-layered-silicate nanocomposites has yielded results for polypropylene-graft-maleic anhydride and polystyrene-layered-silicate nanocomposites using montmorillonite and fluorohectorite. Cone calorimetry was used to measure the heat release rate and other flammability properties of the nanocomposites, under well-controlled combustion conditions. Both the polymer-layered-silicate nanocomposites and the combustion residues were studied by transmission electron microscopy and X-ray diffraction. We have found evidence for a common mechanism of flammability reduction. We also found that the type of layered silicate, nanodispersion, and processing degradation have an influence on the flammability reduction. C1 NIST, Bldg & Fire Res Lab, Fire Sci Div, Gaithersburg, MD 20899 USA. NIST, Div Polymers, Mat Sci & Engn Lab, Gaithersburg, MD 20899 USA. RP Gilman, JW (reprint author), NIST, Bldg & Fire Res Lab, Fire Sci Div, Gaithersburg, MD 20899 USA. RI Morgan, Alexander/A-9672-2009; Manias, Evangelos/A-7557-2011; OI Jackson, Catheryn/0000-0003-1611-3926 NR 31 TC 1182 Z9 1219 U1 20 U2 156 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0897-4756 J9 CHEM MATER JI Chem. Mat. PD JUL PY 2000 VL 12 IS 7 BP 1866 EP 1873 DI 10.1021/cm0001760 PG 8 WC Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA 336CT UT WOS:000088284900010 ER PT J AU Linteris, GT Rumminger, MD Babushok, VI AF Linteris, GT Rumminger, MD Babushok, VI TI Premixed carbon monoxide-nitrous oxide-hydrogen flames: Measured and calculated burning velocities with and without Fe(CO)(5) SO COMBUSTION AND FLAME LA English DT Article ID EXCHANGE-REACTION; DIFFUSION FLAMES; RATE-CONSTANT; N2O; COMBUSTION; KINETICS; IRON; INHIBITION; OXIDATION; CO AB The burning velocity of premixed carbon monoxide-nitrous oxide flames (background water levels of 5 to 15 ppm) has been determined experimentally for a range of fuel-oxidizer equivalence ratio phi from 0.6 to 3.0, with added nitrogen up to a mole fraction of X-N2 = 0.25, and with hydrogen added up to X-H2 = 0.005. Numerical modeling of the flames based on a recently developed kinetic mechanism predicts the burning velocity reasonably well, and indicates that the direct reaction of CO with N2O is the most important reaction for CO and N2O consumption for values of X-H2 less than or equal to 0.0014. The calculations show that a background H-2 level of 10 ppm increases the burning velocity by only about 1% compared to the bone-dry case. Addition of iron pentacarbonyl, Fe(CO)(5), a powerful flame inhibitor in hydrocarbon-air flames, increases the burning velocity of the CO-N2O flames significantly. The promotion is believed to be due to the iron-catalyzed gas-phase reaction of N2O with CO, via N2O + M = N-2 + MO and CO + MO = CO2 + M, where M is Fe, FeO, or FeOH. Published by Elsevier Science Inc. C1 Natl Inst Stand & Technol, Bldg & Fire Res Lab, Gaithersburg, MD 20899 USA. RP Linteris, GT (reprint author), Natl Inst Stand & Technol, Bldg & Fire Res Lab, Bldg 224,Room B356,Stop 8651, Gaithersburg, MD 20899 USA. NR 56 TC 13 Z9 13 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 JUL PY 2000 VL 122 IS 1-2 BP 58 EP 75 DI 10.1016/S0010-2180(00)00103-6 PG 18 WC Thermodynamics; Energy & Fuels; Engineering, Multidisciplinary; Engineering, Chemical; Engineering, Mechanical SC Thermodynamics; Energy & Fuels; Engineering GA 322QM UT WOS:000087520300005 ER PT J AU Lee, S AF Lee, S TI A numerical study of the unsteady wake behind a sphere in a uniform flow at moderate Reynolds numbers SO COMPUTERS & FLUIDS LA English DT Article DE vortex shedding; unsteady wake; sphere; viscous flow; finite element method ID FINITE-ELEMENT METHOD; FREE-STREAM VELOCITY; SHEAR-FLOW; DRAG; MOTION AB Numerical simulations of uniform flow past a sphere are presented for Reynolds numbers from 100 to 500, The Navier-Stokes equations are discretized in three-dimensional space using a Galerkin-type finite element method. A velocity-pressure segregated algorithm using an explicit scheme is implemented for unsteady problems. Extensive computations at Re = 100 are first carried out in order to determine optimal parameters for the simulations, as well as to examine the computational convergence. Unsteady flow fields are successfully simulated by introducing an artificial perturbation into the simulation. The development of asymmetric, stationary wakes at Re > 250 is numerically simulated, which is consistent with experimental observations by others. The occurrence of periodic vortex shedding behind the sphere at RE > 375 agrees with experimental measurements. The shed vortices detaching from a fixed location on the sphere at these Reynolds numbers are also in agreement with previous experimental observations. These results from the present simulations have not been reported in previous numerical studies. Statistical characteristics of the unsteady flow field such as drag, separation angle, and Strouhal number are also in good agreement with compared experimental data, With a further increase of Re to 500, irregularly shaped vortices begin to appear in addition to well-organized vortices, as observed in experiments. Spectral analysis reveals a periodic fluctuation of the vortex detachment location, the period of which is about four times longer than that of individual vortex shedding. (C) 2000 Elsevier Science Ltd. All rights reserved. C1 Univ Colorado, NOAA, Environm Technol Lab, Cooperat Inst Res Environm Sci, Boulder, CO 80303 USA. RP Lee, S (reprint author), Univ Colorado, NOAA, Environm Technol Lab, Cooperat Inst Res Environm Sci, 325 BRoadway, Boulder, CO 80303 USA. NR 40 TC 51 Z9 55 U1 1 U2 12 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0045-7930 J9 COMPUT FLUIDS JI Comput. Fluids PD JUL PY 2000 VL 29 IS 6 BP 639 EP 667 DI 10.1016/S0045-7930(99)00023-7 PG 29 WC Computer Science, Interdisciplinary Applications; Mechanics SC Computer Science; Mechanics GA 309EQ UT WOS:000086755700003 ER PT J AU Miller, MW Weil, E Szmant, AM AF Miller, MW Weil, E Szmant, AM TI Coral recruitment and juvenile mortality as structuring factors for reef benthic communities in Biscayne National Park, USA SO CORAL REEFS LA English DT Article DE coral recruitment; Florida; juvenile corals ID GREAT-BARRIER-REEF; SCLERACTINIAN CORALS; FISH PREDATION; FLORIDA-KEYS; ABUNDANCE; PATTERNS; GROWTH; QUANTIFICATION; ANNULARIS; SURVIVAL AB Coral communities of Biscayne National Park (BNP) on offshore linear bank-barrier reefs are depauperate of reef corals and have little topographic relief, while those on lagoonal patch reefs have greater coral cover and species richness despite presumably more stressful environmental regimes closer to shore. We hypothesized that differences in rates of coral recruitment and/or of coral survivorship were responsible for these differences in community structure. These processes were investigated by measuring: (1) juvenile and adult coral densities, and (2) size-frequency distributions of smaller coral size classes, at three pairs of bank- and patch-reefs distributed along the north-south range of coral reefs within the Park. In addition, small quadrats (0.25 m(2)) were censused for colonies <2 cm in size on three reefs tone offshore and one patch reef in the central park, and one intermediate reef at the southern end), and re-surveyed after 1 year. Density and size frequency data confirmed that large coral colonies were virtually absent from the offshore reefs, but showed that juvenile corals were common and had similar densities to those of adjacent bank and patch reefs. Large coral colonies were more common on inshore patch reefs, suggesting lower survivorship (higher mortality) of small and intermediate sized colonies on the offshore reefs. The more limited small-quadrat data showed similar survivorship rates and initial and final juvenile densities at all three sites, but a higher influx of new recruits to the patch reef site during the single annual study period. We consider the size-frequency data to be a better indicator of juvenile coral dynamics, since it is a more time-integrated measurement and was replicated at more sites. We conclude that lack of recruitment does not appear to explain the impoverished coral communities on offshore bank reefs in BNP. Instead, higher juvenile coral mortality appears to be a dominant factor structuring these communities. C1 Univ Miami, Rosenstiel Sch Marine & Atmospher Sci, Div Marine Biol & Fisheries, Miami, FL 33149 USA. RP Miller, MW (reprint author), NMFS SE Fisheries Sci Ctr, 75 Virginia Beach Dr, Miami, FL 33149 USA. NR 32 TC 82 Z9 87 U1 3 U2 30 PU SPRINGER-VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0722-4028 J9 CORAL REEFS JI Coral Reefs PD JUL PY 2000 VL 19 IS 2 BP 115 EP 123 DI 10.1007/s003380000079 PG 9 WC Marine & Freshwater Biology SC Marine & Freshwater Biology GA 341WM UT WOS:000088614000003 ER PT J AU Nathan, I Dizdaroglu, M Bernstein, L Junker, U Lee, C Muegge, K Durum, SK AF Nathan, I Dizdaroglu, M Bernstein, L Junker, U Lee, C Muegge, K Durum, SK TI Induction of oxidative DNA damage in U937 cells by TNF or anti-Fas stimulation SO CYTOKINE LA English DT Article ID TUMOR-NECROSIS-FACTOR; INDUCED APOPTOSIS; HUMAN FIBROBLASTS; CYTOCHROME-C; CYTOTOXICITY; MITOCHONDRIA; BCL-2; FRAGMENTATION; GLUTATHIONE; INVOLVEMENT AB TNF and Fas signaling pathways are reported to induce mitochondrial damage associated with production of oxygen radicals. We examined whether such radical production elicited detectable nuclear DNA damage in U937 cells following treatment with TNF or with anti-Fas antibodies, Using GC-mass spectroscopy for analysing base oxidation, several oxidized species increased significantly following TNF treatment, whereas anti-Fas resulted in less detectable oxidative damage using this assay. Cytogenetic analysis showed that, in the presence of aphidicolin, which blocks several types of DNA repair, TNF induced extensive chromosomal damage. Aphidicolin also synergized with TNF and anti-Fas in inducing cell death which was prevented by reducing atmospheric oxygen or addition of n-acetyl cysteine, a scavenger of oxygen radicals. Thus, several lines of evidence point to the TNF and Fas pathways inducing extensive oxidative DNA damage and repair, and suggest potential roles for these pathways in mutagenesis and aging. (C) 2000 Academic Press. C1 NCI, Lab Mol Immunol, Frederick, MD 21702 USA. Natl Inst Stand & Technol, Chem Sci & Technol Lab, Gaithersburg, MD 20899 USA. Texas A&M Univ, Hlth Sci Ctr, Dept Pathol & Lab, College Stn, TX 77843 USA. NCI, SAIC, Frederick, MD 21701 USA. RP Durum, SK (reprint author), NCI, Lab Mol Immunol, Frederick, MD 21702 USA. NR 44 TC 14 Z9 14 U1 0 U2 0 PU W B SAUNDERS CO PI PHILADELPHIA PA INDEPENDENCE SQUARE WEST CURTIS CENTER, STE 300, PHILADELPHIA, PA 19106-3399 USA SN 1043-4666 J9 CYTOKINE JI Cytokine PD JUL PY 2000 VL 12 IS 7 BP 881 EP 887 DI 10.1006/cyto.1999.0638 PG 7 WC Biochemistry & Molecular Biology; Cell Biology; Immunology SC Biochemistry & Molecular Biology; Cell Biology; Immunology GA 335AY UT WOS:000088220900006 PM 10880232 ER PT J AU Xu, HHK Smith, DT Schumacher, G Eichmiller, FC Antonucci, JM AF Xu, HHK Smith, DT Schumacher, G Eichmiller, FC Antonucci, JM TI Indentation modulus and hardness of whisker-reinforced heat-cured dental resin composites SO DENTAL MATERIALS LA English DT Article DE ceramic whisker; heat cure; resin composite; filler level; indentation; elastic modulus; brittleness; fracture toughness ID MECHANICAL-PROPERTIES; FILLER PARTICLES; GLASS-CERAMICS; HUMAN ENAMEL; FATIGUE; CONVERSION; STRENGTH; AMALGAM; LEVEL; WATER AB Objectives: Recent studies showed that ceramic whisker reinforcement imparted a two-fold increase in the strength of dental composites. The aim of this study was to investigate the indentation response and measure the elastic modulus, hardness, and brittleness of whisker-reinforced heat-cured resin composites as a function of filler level, heat-cure temperature, and heat-cure duration. Methods: Silica particles were fused onto silicon nitride whiskers to facilitate silanization and to roughen the whiskers for improved retention in matrix. Whisker filler mass fractions of 0, 20, 40, 60, 70, 74 and 79% were tested. Heat-cure temperature ranged from 100 to 180 degrees C, and duration from 10 min to 24 h. A nano-indentation system enabled the measurement of elastic modulus. Fracture toughness was measured and composite brittleness index was calculated. An inlay/onlay composite and a prosthetic composite were tested as controls. Results: Whisker filler level and heat-cure duration had significant effects on composite properties, while heat-cure temperature had nonsignificant effects. The whisker composite with 79% filler level had a modulus in GPa (mean (SD); n = 6) of 26.9 (1.0), significantly higher than 15.1 (0.2) of an inlay/onlay control, and 16.1 (0.3) of a prosthetic control (Tukey's multiple comparison test; family confidence coefficient = 0.95). The fracture toughness in MPa.m(1/2) was 2.22 (0.26) for the whisker composite, higher than 0.95 (0.11) for inlay/onlay control, and (1.13 +/- 0.19) for prosthetic control. The brittleness index was (0.49 +/- 0.07) for whisker composite, lower than (1.02 +/- 0.12) for inlay/onlay control and (0.63 +/- 0.13) for prosthetic control. Significance: Whisker filler level had a profound influence, heat-cure duration had significant effects, while temperature did not have significant effects, on the properties of whisker composite. The whisker composite had significantly higher elastic modulus and fracture toughness, and lower brittleness than the inlay/onlay and prosthetic controls. Published by Elsevier Science Ltd. C1 Natl Inst Stand & Technol, Amer Dent Assoc Hlth Fdn, Paffenbarger Res Ctr, Gaithersburg, MD 20899 USA. Natl Inst Stand & Technol, Div Ceram, Gaithersburg, MD 20899 USA. Natl Inst Stand & Technol, Div Polymer, Gaithersburg, MD 20899 USA. RP Xu, HHK (reprint author), Natl Inst Stand & Technol, Amer Dent Assoc Hlth Fdn, Paffenbarger Res Ctr, Gaithersburg, MD 20899 USA. RI Smith, Douglas/I-4403-2016 OI Smith, Douglas/0000-0002-9358-3449 FU NIDCR NIH HHS [R29 DE12476] NR 38 TC 38 Z9 39 U1 0 U2 2 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 JUL PY 2000 VL 16 IS 4 BP 248 EP 254 DI 10.1016/S0109-5641(00)00014-2 PG 7 WC Dentistry, Oral Surgery & Medicine; Materials Science, Biomaterials SC Dentistry, Oral Surgery & Medicine; Materials Science GA 321RD UT WOS:000087467700003 PM 10831779 ER PT J AU Fonseca, MS Julius, BE Kenworthy, WJ AF Fonseca, MS Julius, BE Kenworthy, WJ TI Integrating biology and economics in seagrass restoration: How much is enough and why? SO ECOLOGICAL ENGINEERING LA English DT Article; Proceedings Paper CT Symposium on Goal Setting and Success Criteria for Coastal Habitat Restoration CY JAN 13-15, 1998 CL CHARLESTON, SOUTH CAROLINA DE seagrass; restoration; success criteria; goals; discounting; lost ecological services; recovery; habitat equivalency; population growth ID SYRINGODIUM-FILIFORME; THALASSIA-TESTUDINUM; FLORIDA BAY; GROWTH; DYNAMICS; USA; PRODUCTIVITY; DEMOGRAPHY; LAGOON; BED AB Although success criteria for seagrass restoration have been in place for some time, there has been little consistency regarding how much habitat should be restored for every unit area lost (the replacement ratio). Extant success criteria focus on persistence, al ca, and habitat quality (shoot density). These metrics, while conservative, remain largely accepted For the seagrass ecosystem. Computation of the replacement ratio using economic tools has recently been integrated with seagrass restoration and is based on the intrinsic recovery rate of the injured seagrass beds themselves as compared with the efficacy of the restoration itself. In this application, field surveys of injured seagrass beds in the Florida Keys National Marine Sanctuary (FKNMS) were conducted over several years and provide the basis for computing the intrinsic recovery rate and thus, the replacement ratio. This computation is performed using the Habitat Equivalency Analysis (HEA) and determines the lost on-site services pertaining to the ecological function of an area as the result of an injury and sets this against the difference between intrinsic recovery and recovery afforded by restoration. Joining empirical field data with economic theory has produced a reasonable and typically conservative means of determining the level of restoration and this has been fully supported in Federal Court rulings. Having clearly defined project goals allows application of the success criteria in a predictable, consistent, reasonable, and fair manner. Published by Elsevier Science B.V. C1 Natl Ocean Serv, NOAA, Ctr Coastal Fisheries & Habitat Res, Beaufort, NC 28516 USA. Natl Ocean Serv, NOAA, Damage Assessment Ctr, Silver Spring, MD 20910 USA. RP Fonseca, MS (reprint author), Natl Ocean Serv, NOAA, Ctr Coastal Fisheries & Habitat Res, 101 Pivers Isl Rd, Beaufort, NC 28516 USA. NR 32 TC 45 Z9 50 U1 5 U2 30 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0925-8574 J9 ECOL ENG JI Ecol. Eng. PD JUL PY 2000 VL 15 IS 3-4 BP 227 EP 237 DI 10.1016/S0925-8574(00)00078-1 PG 11 WC Ecology; Engineering, Environmental; Environmental Sciences SC Environmental Sciences & Ecology; Engineering GA 340RW UT WOS:000088549600007 ER PT J AU Reed, DC Raimondi, PT Carr, MH Goldwasser, L AF Reed, DC Raimondi, PT Carr, MH Goldwasser, L TI The role of dispersal and disturbance in determining spatial heterogeneity in sedentary organisms SO ECOLOGY LA English DT Article DE Channel Islands National Park; colonization; dispersal; disturbance; El Nino; kelp forest; larvae; propagule; sedentary organisms; spatial heterogeneity; spore; variability ID SETTLING INVERTEBRATE LARVAE; KELP MACROCYSTIS-PYRIFERA; EL-NINO; SOUTHERN-CALIFORNIA; SEASONAL VARIABILITY; PATCHY ENVIRONMENTS; COMMUNITY STRUCTURE; BIOORGANIC FILMS; SEA-URCHINS; GIANT-KELP AB The dispersal ability of seeds, spores, and larvae can greatly influence spatial heterogeneity in the abundance of plants and sedentary animals, especially after a severe and widespread disturbance has caused extensive population declines and opened large areas for colonization by propagules. However, little work has been done on the relationship between propagule dispersal and spatial heterogeneity in species abundance. We hypothesize that, shortly after a disturbance, spatial variability in abundance of sedentary organisms is negatively related to the dispersal potential of a species' propagules, and that this negative relationship diminishes over time as populations recover from the disturbance. To evaluate this hypothesis, we examined temporal changes in spatial patterns of abundance in a diverse group of sedentary marine organisms, whose propagules differ greatly in dispersal potential. The data set was derived from long-term monitoring of the kelp forest communities of Channel Islands National Park and contained annual estimates of abundance of 27 species from nine phyla collected at 16 sites on five different islands during 1986-1994. Among-site variability in the abundance of plants and animals was negatively related to the plank tonic duration of a species' propagules. The negative relationship disappeared over time in some regions, but not in others. This disappearance resulted primarily from species with relatively limited dispersal becoming more uniformly distributed over time; among-site variability of species with more widespread dispersal changed little. Differences among regions in the rate at which the negative relationship diminished over time suggested regional differences in rates of recovery from the 1982-1984 El Nino disturbance. These differences among regions may have resulted in part from differences in the frequency and intensity of sea urchin grazing, and in part from regional differences in the distances separating sites where abundances were measured. Our findings support the hypothesis that differential dispersal after large disturbances can significantly influence spatial heterogeneity in assemblages of sedentary organisms. C1 Univ Calif Santa Barbara, Inst Marine Sci, Santa Barbara, CA 93106 USA. Univ Calif Santa Cruz, Dept Biol, Santa Cruz, CA 95064 USA. Natl Marine Fisheries Serv, SW Fisheries Sci Ctr, NOAA, Tiburon, CA USA. RP Reed, DC (reprint author), Univ Calif Santa Barbara, Inst Marine Sci, Santa Barbara, CA 93106 USA. EM reed@lifesci.ucsb.edu NR 96 TC 68 Z9 69 U1 1 U2 30 PU ECOLOGICAL SOC AMER PI WASHINGTON PA 1990 M STREET NW, STE 700, WASHINGTON, DC 20036 USA SN 0012-9658 J9 ECOLOGY JI Ecology PD JUL PY 2000 VL 81 IS 7 BP 2011 EP 2026 PG 16 WC Ecology SC Environmental Sciences & Ecology GA 334YQ UT WOS:000088214400021 ER PT J AU Hartwell, SI Alden, RW Wright, DA Ailstock, S Kerhin, R AF Hartwell, SI Alden, RW Wright, DA Ailstock, S Kerhin, R TI Correlation of measures of ambient toxicity and fish community diversity in a Chesapeake Bay tributary, Maryland, USA: A biological, chemical, and geological assessment SO ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY LA English DT Article DE ambient toxicity; risk assessment; estuaries; sediment chemistry; watershed ID GUIDELINES; ESTUARIES; SEDIMENTS AB A battery of water column and sediment toxicity bioassays measuring lethal and sublethal endpoints were employed with fish, invertebrates, vascular plants, and bacteria. Monthly water column bioassays were conducted with water from three stations in the South River, Maryland, USA, and from a reference station in the Wicomico River (Maryland, USA). Sediment bioassays were conducted with five discrete samples taken from each station. Water column assays indicated low-level effects at the upstream stations in the South River. Animal species demonstrated higher responses than did plants. Chemical analyses revealed only trace levels of heavy metals. Sediment in the upper stations of the South River demonstrated significant toxicity to animal but not plant test species. Sediment chemistry indicated elevated levels of heavy metals and polycyclic aromatic hydrocarbons. The sediments are enriched with chromium, copper, iron, manganese, cadmium, and lead-above normalized background geochemical ratios. The toxicological risk ranking model identified a strong gradient from upstream to downstream. Toxicological risk scores for the downstream station in the South River were comparable to those for the reference station. The major source of contaminants in the South River is probably derived from a multitude of non-point sources associated with urbanization within the watershed. The upper stations are in a zone of deposition of riverine material, whereas the downstream station is dominated by open Chesapeake Bay dynamics. C1 Maryland Dept Nat Resources, Tidewater Ecosyst Assessment Div, Annapolis, MD 21401 USA. Univ Nevada, Coll Sci, Las Vegas, NV 89154 USA. Univ Maryland, Chesapeake Biol Lab, Solomons, MD 20688 USA. Ctr Environm, Anne Arundel Community Coll, Arnold, MD 21012 USA. Maryland Geol Survey, Maryland Dept Nat Resources, Baltimore, MD 21218 USA. RP Hartwell, SI (reprint author), NOAA, Natl Ocean Serv, Natl Ctr Coastal Ocean Sci, 1305 East West Highway, Silver Spring, MD 20910 USA. NR 38 TC 3 Z9 3 U1 1 U2 6 PU SETAC PI PENSACOLA PA 1010 NORTH 12TH AVE, PENSACOLA, FL 32501-3367 USA SN 0730-7268 J9 ENVIRON TOXICOL CHEM JI Environ. Toxicol. Chem. PD JUL PY 2000 VL 19 IS 7 BP 1753 EP 1763 DI 10.1897/1551-5028(2000)019<1753:COMOAT>2.3.CO;2 PG 11 WC Environmental Sciences; Toxicology SC Environmental Sciences & Ecology; Toxicology GA 325KK UT WOS:000087674600008 ER PT J AU Abookire, AA Piatt, JF Robards, MD AF Abookire, AA Piatt, JF Robards, MD TI Nearshore fish distributions in an Alaskan estuary in relation to stratification, temperature and salinity SO ESTUARINE COASTAL AND SHELF SCIENCE LA English DT Article DE forage fish; nearshore (zone); stratification; temperature; salinity; distribution; estuarine habitat; Alaska ID JUVENILE FISH; RIVER PLUME; HABITAT; LARVAE; RECRUITMENT; ABUNDANCE; BAY; CALIFORNIA; COAST AB Fish were sampled with beach seines and small-meshed beam trawls in nearshore (<1 km) and shallow (<25 m) habitats on the southern coast of Kachemak Bay, Cook Inlet, Alaska, from June to August, 1996-1998. Fish distributions among habitats were analysed for species composition, catch-per-unit-effort (CPUE) and frequency of occurrence. Two oceanographically distinct areas of Kachemak Bay were sampled and compared: the Outer Bay and the Inner Bay. Outer Kachemak Bay is exposed and receives oceanic, upwelled water from the Gulf of Alaska, whereas the Inner Bay is more estuarine. Thermohaline properties of bottom water in the Outer and Inner Bay were essentially the same, whereas the Inner Bay water-column was stratified with warmer, less saline waters near the surface. Distribution and abundance of pelagic schooling fish corresponded with area differences in stratification, temperature and salinity. The Inner Bay supported more species and higher densities of schooling and demersal fish than the Outer Bay. Schooling fish communities sampled by beach seine differed between the Outer and Inner Bays. Juvenile and adult Pacific sand lance (Ammodytes hexapterus), Pacific herring (Clupea harengus pallasi), osmerids (Osmeridae) and sculpins (Cottidae) were all more abundant in the Inner Bay. Gadids (Gadidae) were the only schooling fish taxa more abundant in the Outer Bay. Thermohaline characteristics of bottom water were similar throughout Kachemak Bay. Correspondingly, bottom fish communities were similar in all areas. Relative abundances (CPUE) were not significantly different between areas for any of the five demersal fish groups: flatfishes (Pleuronectidae), ronquils (Bathymasteridae), sculpins (Cottidae), gadids (Gadidae) and pricklebacks (Stichaeidae). C1 US Geol Survey, Alaska Biol Sci Ctr, Anchorage, AK 99503 USA. RP Abookire, AA (reprint author), Natl Marine Fisheries Serv, 301 Res Court, Kodiak, AK 99615 USA. EM alisa.abookire@noaa.gov NR 46 TC 37 Z9 41 U1 4 U2 15 PU ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 0272-7714 J9 ESTUAR COAST SHELF S JI Estuar. Coast. Shelf Sci. PD JUL PY 2000 VL 51 IS 1 BP 45 EP 59 DI 10.1006/ecss.1999.0615 PG 15 WC Marine & Freshwater Biology; Oceanography SC Marine & Freshwater Biology; Oceanography GA 348NA UT WOS:000088989800004 ER PT J AU Bourbigot, S Le Bras, M Dabrowski, F Gilman, JW Kashiwagi, T AF Bourbigot, S Le Bras, M Dabrowski, F Gilman, JW Kashiwagi, T TI PA-6 clay nanocomposite hybrid as char forming agent in intumescent formulations SO FIRE AND MATERIALS LA English DT Article ID NUCLEAR MAGNETIC-RESONANCE; SOLID-STATE C-13; MECHANICAL-PROPERTIES; CHEMICAL-SHIFT; AL-27 NMR; MAS NMR; ADDITIVES; POLYMER; ZEOLITE; SURFACE AB This work deals with new flame retardant (FR) intumescent formulations for ethylene-vinyl acetate copolymers (EVA) using charring polymers polyamide-6 (PA-6) and polyamide-6 clay nanocomposite hybrid (PA-6-nano) as carbonization agents, Use of PA-6 nano improved both the mechanical and fire properties of FR EVA-based materials, The part played by the clay in the improvement of the FR performance was studied using FTIR and solid state NMR, It is shown that the clay allowed the thermal stabilization of a phosphorocarbonaceous structure in the intumescent char which increased the efficiency of the shield and, in addition, the formation of a 'ceramic' which can act as a protective barrier. Copyright (C) 2000 John Wiley & Sons, Ltd. C1 ENSAIT, Lab Genie & Mat Text GEMTEX, UPRES, EA2161, F-59056 Roubaix 01, France. Univ Sci & Technol Lille, ENSCL, GEPIFREM, UPRES,EA 2698, F-59652 Villeneuve Dascq, France. Natl Inst Stand & Technol, Fire Sci Div, Mat Fire Res Grp, Gaithersburg, MD 20899 USA. RP Bourbigot, S (reprint author), ENSAIT, Lab Genie & Mat Text GEMTEX, UPRES, EA2161, BP 30329, F-59056 Roubaix 01, France. OI Bourbigot, Serge/0000-0003-1536-2015 NR 42 TC 214 Z9 235 U1 4 U2 54 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX PO19 1UD, ENGLAND SN 0308-0501 J9 FIRE MATER JI Fire Mater. PD JUL-AUG PY 2000 VL 24 IS 4 BP 201 EP 208 DI 10.1002/1099-1018(200007/08)24:4<201::AID-FAM739>3.0.CO;2-D PG 8 WC Materials Science, Multidisciplinary SC Materials Science GA 357LE UT WOS:000089502500005 ER PT J AU Polonio, RE Wolke, RE MacLean, SA Sperry, JF AF Polonio, RE Wolke, RE MacLean, SA Sperry, JF TI An in vitro assay to measure phagocytosis in striped bass hybrids (Morone saxatilis x Morone chrysops) SO FISH & SHELLFISH IMMUNOLOGY LA English DT Article DE striped bass hybrid; peritoneal phagocytes; macrophages; phagocytosis; latex beads; in vitro assay ID CELL-WALL GLUCAN; SPARUS-AURATA; MACROPHAGES; FISH; ACTIVATION; LEUKOCYTES; MICROSCOPY AB An in vitro phagocytosis assay was developed for hybrid striped bass (Morone saxatilis x Morone chrysops), using cells collected from the peritoneal cavity of this fish. The findings indicated that: (1) 10 days following a single intraperitoneal injection (1 ml) of Freund's incomplete adjuvant (FIA) was an appropriate time for collecting suitable working concentrations (5.3 +/- 4.0 x 10(7) cells ml(-1)) of peritoneal phagocytes (83.7 +/- 1.5% macrophages) from these hybrids held at 23 degrees C; (2) these cells phagocytosed latex beads (polystyrene microspheres 3.12 mu m in diameter) after 30 min of in vitro incubation at room temperature (25 +/- 1 degrees C). The phagocytic ability and phagocytic capacity in a washed adherent layer exposure system were 67.2 +/- 2.76% and 4.14 +/- 0.35 beads phagocyte-1, respectively. These results strongly suggest that a simple methodology, including baseline data serving as guidelines, is now available for conducting in vitro phagocytosis assays in this hybrid. (C) 2000 Academic Press. C1 Univ Rhode Isl, Dept Biochem Microbiol & Mol Genet, Kingston, RI 02881 USA. Univ Rhode Isl, Dept Fisheries Anim & Vet Sci, Kingston, RI 02881 USA. NOAA, Natl Marine Fisheries Serv, Narragansett, RI 02882 USA. RP Polonio, RE (reprint author), Univ Rhode Isl, Dept Biochem Microbiol & Mol Genet, Kingston, RI 02881 USA. EM rpol8053@postoffice.uri.edu NR 45 TC 3 Z9 4 U1 0 U2 1 PU ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 1050-4648 J9 FISH SHELLFISH IMMUN JI Fish Shellfish Immunol. PD JUL PY 2000 VL 10 IS 5 BP 405 EP 418 DI 10.1006/fsim.1999.0248 PG 14 WC Fisheries; Immunology; Marine & Freshwater Biology; Veterinary Sciences SC Fisheries; Immunology; Marine & Freshwater Biology; Veterinary Sciences GA 336FZ UT WOS:000088292400002 PM 10994586 ER PT J AU Jech, JM Luo, JG AF Jech, JM Luo, JG TI Digital echo visualization and information system (DEVIS) for processing spatially-explicit fisheries acoustic data SO FISHERIES RESEARCH LA English DT Article DE fisheries acoustics data processing ID FISH TARGET STRENGTH; PELAGIC FISH; CHESAPEAKE BAY; GROWTH-RATE; MODELS; PLANKTIVORES; SCATTERING; ABUNDANCE; BIOMASS; SIZE AB Spatially explicit analysis of fisheries acoustic data preserves heterogeneity observed in spatial distributions of fish. A software system - Digital Echo Visualization and Information System (DEVIS) - has been developed to process digital underwater acoustic data fur spatially-explicit fisheries acoustic research. This system can be used to obtain spatial and temporal distributions of fish density, fish abundance, and fish lengths for management applications and for ecological modeling. DEVIS first reads digital data, corrects the data according to the sonar equation, discriminates individual targets, and vertically and horizontally integrates the data into a two-dimensional array of mean volume backscattering strength. Individual target information (TS, spatial location) is meshed with the volume backscattering array, and representative acoustic sizes are estimated in array cells with missing target information. Estimation methods for acoustic sizes and potential biases in abundance estimates are introduced and discussed. The final output is the spatial distribution of numeric density and fish length by length classes and for all fish. Data obtained on Lake Erie in September 1994 and on Chesapeake Bay in July 1995 were processed using DEVIS and are shown graphically. Steps required to process digital data are described and how these data can be applied to fish ecology is shown. Published by Elsevier Science B.V. C1 NOAA, Great Lakes Environm Res Lab, Cooperat Inst Limnol & Ecosyst Res, Ann Arbor, MI 48105 USA. RP Jech, JM (reprint author), NOAA, Great Lakes Environm Res Lab, Cooperat Inst Limnol & Ecosyst Res, 2205 Commonwealth Blvd, Ann Arbor, MI 48105 USA. NR 49 TC 5 Z9 5 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0165-7836 J9 FISH RES JI Fish Res. PD JUL PY 2000 VL 47 IS 2-3 BP 115 EP 124 PG 10 WC Fisheries SC Fisheries GA 325CJ UT WOS:000087658500003 ER PT J AU Demer, DA Barange, M Boyd, AJ AF Demer, DA Barange, M Boyd, AJ TI Measurements of three-dimensional fish school velocities with an acoustic Doppler current profiler SO FISHERIES RESEARCH LA English DT Article DE fish; three-dimensional; velocities; Doppler; ADCP; behavior AB A method was developed to measure horizontal and vertical velocities of acoustic scattering layers using a multi-beam acoustic Doppler current profiler (ADCP), To determine three orthogonal velocity vectors (east, north, and vertical), it was required that the ADCP beams simultaneously insonified a coherently moving fish school in the same depth bin. Velocity vectors that satisfied these conditions were extracted from individual ping velocity estimates and ensemble-averaged to determine the average speeds and directions of fish aggregations. The results indicate that the ADCP can be a useful tool for observing fish and possibly zooplankton behavior in certain situations, Preliminary investigations include the quantification of horizontal and vertical migration patterns and possible vessel avoidance reaction of large schools of sardine in False Bay, South Africa. The method can be enhanced by refining equipment parameters such as water mode and depth bin length, correcting for rotational motion of the ADCP platform, and possibly by directly processing the radial velocity components from each beam. (C) 2000 Elsevier Science B.V. All rights reserved. C1 SW Fisheries Sci Ctr, La Jolla, CA 92038 USA. RP Demer, DA (reprint author), SW Fisheries Sci Ctr, 8604 La Jolla Shores Dr, La Jolla, CA 92037 USA. RI Barange, Manuel/D-2689-2016 OI Barange, Manuel/0000-0002-1508-0483 NR 15 TC 21 Z9 21 U1 2 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0165-7836 J9 FISH RES JI Fish Res. PD JUL PY 2000 VL 47 IS 2-3 BP 201 EP 214 DI 10.1016/S0165-7836(00)00170-3 PG 14 WC Fisheries SC Fisheries GA 325CJ UT WOS:000087658500010 ER PT J AU Hewitt, RP Demer, DA AF Hewitt, RP Demer, DA TI The use of acoustic sampling to estimate the dispersion and abundance of euphausiids, with an emphasis on Antarctic krill, Euphausia superba SO FISHERIES RESEARCH LA English DT Review DE SONAR; active acoustics; zooplankton; euphausiids; CCAMLR ID ELEPHANT-ISLAND; TARGET STRENGTH; SOUTH-GEORGIA; BACKSCATTERING STRENGTH; ZOOPLANKTON SIZE; SOUND SCATTERING; VARIABILITY; PREY; ORIENTATION; PATTERNS AB Acoustic sampling has been used to investigate the ecology of Antarctic krill (Euphausia superba) and to provide information on dispersion and abundance necessary to manage their harvest. Population estimates based on multi-ship acoustic surveys have been used to set catch limits. More localized acoustic surveys have been conducted to study the response of land-breeding krill predators to local variations in their food supply. These and future surveys may result in additional controls on the fishery. In this context, the use of acoustics to survey euphausiids is reviewed and major sources of uncertainty are discussed. These issues are organized as they pertain to the two broad steps of acoustic surveys: (1) estimating the volumetric density of krill (measurement uncertainty) and (2) mapping krill distribution and estimating abundance (sampling uncertainty). Published by Elsevier Science B.V. C1 SW Fisheries Sci Ctr, La Jolla, CA 92038 USA. RP Hewitt, RP (reprint author), SW Fisheries Sci Ctr, POB 271, La Jolla, CA 92038 USA. NR 128 TC 44 Z9 52 U1 1 U2 17 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0165-7836 J9 FISH RES JI Fish Res. PD JUL PY 2000 VL 47 IS 2-3 BP 215 EP 229 DI 10.1016/S0165-7836(00)00171-5 PG 15 WC Fisheries SC Fisheries GA 325CJ UT WOS:000087658500011 ER PT J AU Bolles, KL Begg, GA AF Bolles, KL Begg, GA TI Distinction between silver hake (Merluccius bilinearis) stocks in US waters of the northwest Atlantic based on whole otolith morphometrics SO FISHERY BULLETIN LA English DT Article ID FISHERIES MANAGEMENT; IDENTIFICATION; GROWTH; SHAPE; DISCRIMINATION AB A method for using whole otolith morphometrics to identify silver hake (Merluccius bilinearis) stocks in U.S. waters of the northwest Atlantic is described. Whole sagittal otolith morphometric variables of length, width, area, perimeter, circularity, and rectangularity were extracted by image processing and, in combination with age-specific discriminant analyses, were used to differentiate two stocks of silver hake: a northern stock from the Gulf of Maine to northern Georges Bank and a southern stock from southern Georges Bank to the Middle Atlantic. Further support for these groupings is supported by growth rate analyses: fish of the northern stock grew slower than those of the southern stock, resulting in typically larger otoliths for fish from the northern stock. This study demonstrates that whole otolith morphometrics, specific to fish age, are useful in identifying silver hake stocks and can be a useful tool in identifying other fish stocks. C1 NOAA, Natl Marine Fisheries Serv, NE Fisheries Sci Ctr, Woods Hole, MA 02543 USA. RP Bolles, KL (reprint author), Marine Res Inst, Skulagaa 4,POB 1390, IS-121 Reykjavik, Iceland. NR 40 TC 40 Z9 42 U1 3 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 JUL PY 2000 VL 98 IS 3 BP 451 EP 462 PG 12 WC Fisheries SC Fisheries GA 341LT UT WOS:000088592400001 ER PT J AU DeMartini, EE Uchiyama, JH Williams, HA AF DeMartini, EE Uchiyama, JH Williams, HA TI Sexual maturity, sex ratio, and size composition of swordfish, Xiphias gladius, caught by the Hawaii-based pelagic longline fishery SO FISHERY BULLETIN LA English DT Article ID REPRODUCTION; FLORIDA; WATERS AB Swordfish (Xiphias gladius) caught by the Hawaii-based pelagic longline fishery during March 1994-June 1997 were examined at sea by observers of the National Marine Fisheries Service, Southwest Region. Observers provided unbiased size and sex composition data for 4.8% of the swordfish catch and 4.9% of the effort in number of hooks of the fishery during the 40-mo. period. Observers measured body lengths for more than 8600 swordfish brought aboard participating vessels; sex, based on macroscopic appearance of gonads, was identified aboard ship for 77% of measured fish. Sex identifications were later verified (0.5% error rate) and gonadal developmental stage described for 1336 fish whose sex was identified in the field. Logistic regression was used to estimate sex-specific, median body size at sexual maturity (L-50) by using microscopic morphological evidence for gonadal development. L-50 was 102 cm +/-2.5 (95% CI) cm eye-to-fork length (EFL and 144 +/- 2.8 cm EFL for males (n=506) and females (n=822), respectively. Sex ratios were an increasing power function between 100 and 220 cm, and nearly all fish >220 cm EFL were females. Sex composition and body size varied temporally and spatially, especially the latter. Relatively more males were caught south of 27 degrees N: females dominated catches north of 27 degrees N. Small-bodied fish of both sexes prevailed year-round below 22 degrees N. A greater percentage of large-bodied (>156-cm [males], >172-cm [females] EFL fish were caught north of 35 degrees N during the late summer-early Minter. The latter observations are consistent with several nonmutually exclusive hypotheses of migration energetics and body muscle heat conservation, both of which ale discussed. C1 NOAA, Natl Marine Fisheries Serv, SW Fisheries Sci Ctr, Honolulu Lab, Honolulu, HI 96822 USA. RP DeMartini, EE (reprint author), NOAA, Natl Marine Fisheries Serv, SW Fisheries Sci Ctr, Honolulu Lab, 2570 Dole St, Honolulu, HI 96822 USA. NR 49 TC 42 Z9 46 U1 0 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 JUL PY 2000 VL 98 IS 3 BP 489 EP 506 PG 18 WC Fisheries SC Fisheries GA 341LT UT WOS:000088592400004 ER PT J AU Drass, DM Bootes, KL Lyczkowski-Shultz, J Comyns, BH Holt, GJ Riley, CM Phelps, RP AF Drass, DM Bootes, KL Lyczkowski-Shultz, J Comyns, BH Holt, GJ Riley, CM Phelps, RP TI Larval development of red snapper, Lutjanus campechanus, and comparisons with co-occurring snapper species SO FISHERY BULLETIN LA English DT Article ID YELLOWTAIL SNAPPER; ATLANTIC; IDENTIFICATION; CHRYSURUS; PISCES; FISHES AB The larval development of red snapper, Lutjanus campechanus, is described from reared larvae and from specimens collected in the Gulf of Mexico (GOM). Snapper larvae are pelagic and are characterized by the following features: a deep and compressed, lightly pigmented body; moderately short gut; 24 myomeres; and elongated dorsal and pelvic fins that form early in development. Specimens of L. campechanus (1.9 to 26.1 mm) also showed the presence of weak serrations on pelvic-fin spines, absence of serrations on preopercular or dorsal spines, early forming pigment in dorsal and pelvic fins, and notochord flexion between 3.6 and 5.5 mm. Preflexion larvae of the snapper subfamily Lutjaninae in GOM collections cannot be reliably identified to species despite recent larval descriptions. Species-specific differences in number, spacing, and size of melanophores in the postanal ventral series are evident in the youngest larvae of species from the GOM whose development has been described (Ocyurus chrysurus, L. analis, L. synagris, L, griseus, L. campechanus, and Rhomboplites aurorubens) but further evaluation of the utility of these characters is needed. Characteristics that distinguish mid- to late-flexion larvae of these species are compiled in our study and discussed. Among known GOM lutjanine larvae, body depth, pelvic-ray length and serrations on the angle spine of the preopercle can be used in combination with pigmentation to identify larvae to species. Presence of melanistic pigment land size at first appearance) or absence of melanistic pigment in the following locations are useful characters for larval snapper identification: anterior surface of the visceral mass, ventral to notochord flexure; internal area over the notochord; dorsal midline of caudal peduncle; soft dorsal fin; analfin base ol membrane; and pelvic fin. C1 NOAA, Natl Marine Fisheries Serv, Pascagoula, MS 39567 USA. Univ Texas, Inst Marine Sci, Port Aransas, TX 78373 USA. Gulf Coast Res Lab, Ocean Springs, MS 39564 USA. Gulf Coast Bird Observ, Lake Jackson, TX 77566 USA. Auburn Univ, Dept Fisheries & Allied Aquacultures, Auburn, AL 36849 USA. RP Drass, DM (reprint author), NOAA, Natl Marine Fisheries Serv, 3209 Frederick St, Pascagoula, MS 39567 USA. NR 32 TC 16 Z9 16 U1 0 U2 6 PU NATL MARINE FISHERIES SERVICE SCIENTIFIC PUBL OFFICE PI SEATTLE PA 7600 SAND POINT WAY NE BIN C15700, SEATTLE, WA 98115 USA SN 0090-0656 J9 FISH B-NOAA JI Fish. Bull. PD JUL PY 2000 VL 98 IS 3 BP 507 EP 527 PG 21 WC Fisheries SC Fisheries GA 341LT UT WOS:000088592400005 ER PT J AU Orr, JW Matarese, AC AF Orr, JW Matarese, AC TI Revision of the genus Lepidopsetta Gill, 1862 (Teleostei : Pleuronectidae) based on larval and adult morphology, with a description of a new species from the North Pacific Ocean and Bering Sea SO FISHERY BULLETIN LA English DT Article ID COLLECTIONS AB The endemic North Pacific pleuronectid genus Lepidopsetta Gill is revised to include three species: L. bilineata (Ayres), L. polyxystra n. sp., and L, mochigarei Snyder. Adults of L. bilineata can be distinguished by a low gill-raker count and high supraorbital pore count, larvae may be distinguished by four dorsal midline melanophores, heavy finfold pigment, a short snout-to-anus length, and a deep body. The species ranges from Baja California to the eastern Aleutian Islands and the extreme southeastern Bering Sea. Adults of L, mochigarci are distinguished from all other members of Lepidopsetta by higher scale and preopercular pore counts and lower gill-raker and supraorbital pore counts. Larvae are similar to larvae oft. bilineata but can be distinguished by their postanal pigment pattern and melanophores on pectoral-fin rays. Lepidopsetta mochigarei ranges from the southern Sea of Okhotsk to Korea. Adults of L. polyxystra n. sp. are diagnosed by a high gill-raker count and low supraorbital pore count; larvae are diagnosed by two dorsal midline melanophores, light finfold pigment, long snout-to-anus length, and a slender body. The species is found from Puget Sound through the Bering Sea and Aleutian Islands to the Kuril Islands, overlapping with L. bilineata from the extreme southeastern Bering Sea to Puget Sound and with L, mochigarei in the southern Sea of Okhotsk. Synonymies, diagnoses, descriptions, and geographic distributions are provided for adults and larvae of all species; keys are provided for adults. Descriptions of early juveniles of eastern North Pacific species are also presented. Under the name of L. bilineata, L. polyxystra n. sp, has been the subject of many studies of eastern North Pacific Lepidopsetta. All previous studies of specimens from the southeastern Bering Sea into Puget Sound should be considered applicable at the generic level only, unless voucher specimens are verifiable. C1 NOAA, Natl Marine Fisheries Serv, Resource Assessment & Conservat Engn Div, Alaska Fisheries Sci Ctr, Seattle, WA 98115 USA. RP Orr, JW (reprint author), NOAA, Natl Marine Fisheries Serv, Resource Assessment & Conservat Engn Div, Alaska Fisheries Sci Ctr, 7600 Sand Point Way NE, Seattle, WA 98115 USA. NR 93 TC 38 Z9 45 U1 0 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 JUL PY 2000 VL 98 IS 3 BP 539 EP 582 PG 44 WC Fisheries SC Fisheries GA 341LT UT WOS:000088592400007 ER PT J AU Ortiz, M Legault, CM Ehrhardt, NM AF Ortiz, M Legault, CM Ehrhardt, NM TI An alternative method for estimating bycatch from the US shrimp trawl fishery in the Gulf of Mexico, 1972-1995 SO FISHERY BULLETIN LA English DT Article ID LOGNORMAL-BASED ESTIMATORS; ABUNDANCE; ROBUSTNESS AB Finfish bycatch taken by the U.S. Gulf of Mexico shrimp fishery is an important issue in the management of fisheries resources given the perceived high mortality of the different fish stocks taken as bycatch in the region. Bycatch data are characterized by a high number of low catches, a few high catches, and depending on the finfish species, a significant proportion of observations with zero bycatch. An evaluation of the current general linear model for generating bycatch estimates indicates that the bycatch data do not conform to the assumptions of this model because bycatch estimates depend upon choices within the model that can significantly change the results of the model. These choices include the constant value added to catch-per-unit-of-effort (CPUE) values prior to the logarithmic transformation (to avoid undefined logarithms with zero CPUEs) and the standard time-unit selection for calculating CPUE, values from catch in numbers and variable tow times. Currently a value of one is added to observed CPUE, and a constant time unit of one hour has been used; however these choices are somewhat arbitrary. An alternative approach to model bycatch data is to use a delta distribution that has two components. Component one models the proportion of zeros, and component two models the positive catches. In our study we applied the delta lognormal model to estimate finfish bycatch in the shrimp fishery. This model avoids the problems of 1) the addition of a constant positive value to log-transformed CPUEs, and 2) the selection of a standard time unit for CPUE calculations. Bycatch estimates determined with the current general linear model were compared with those determined with the delta lognormal model for Atlantic croaker (Micropogonias undulatus), red snapper (Lutjanus campechanus), Spanish mackerel (Scomberomorus maculatus), and all finfish from 1972 through 1995. Analysis and evaluation of the performance of the delta lognormal model indicated that this model fits the bycatch database better than the current general linear model. C1 Univ Miami, Rosenstiel Sch Marine & Atmospher Sci, Div Marine Biol & Fisheries, Miami, FL 33149 USA. RP Ortiz, M (reprint author), NOAA, Miami Lab, SE Fisheries Sci Ctr, Natl Marine Fisheries Serv, 75 Virginia Beach Dr, Miami, FL 33149 USA. NR 15 TC 35 Z9 38 U1 0 U2 6 PU NATL MARINE FISHERIES SERVICE SCIENTIFIC PUBL OFFICE PI SEATTLE PA 7600 SAND POINT WAY NE BIN C15700, SEATTLE, WA 98115 USA SN 0090-0656 J9 FISH B-NOAA JI Fish. Bull. PD JUL PY 2000 VL 98 IS 3 BP 583 EP 599 PG 17 WC Fisheries SC Fisheries GA 341LT UT WOS:000088592400008 ER PT J AU Taylor, RG Whittington, JA Grier, HJ Crabtree, RE AF Taylor, RG Whittington, JA Grier, HJ Crabtree, RE TI Age, growth, maturation, and protandric sex reversal in common snook, Centropomus undecimalis, from the east and west coasts of South Florida SO FISHERY BULLETIN LA English DT Article ID LATES-CALCARIFER; MORTALITY; WATERS; FISHES AB During 1986-91, we examined 2088 common snook. Centropomus undecimalis, captured in Jupiter and Lake Worth inlets and adjacent waters on the east coast of Florida and 1784 common snook captured in Tampa Bay on the west coast of Florida. Of fish that were sexed, females ranged in length from 397 to 1105 mm FL. and males ranged from 124 to 925 mm FL. East coast fish were larger overall than west coast fish. Age of common snook was determined from sectioned otoliths. Results from the return of 80 oxytetracycline-marked otoliths combined with analyses of monthly patterns in marginal increments and the percentage of otoliths with an annulus on the edge, demonstrated that a single annulus is formed each year. Common snook can live to 21 years, but most of the fish in our sample were from 1 to 7 years old. The von Bertalanffy growth models were significantly different (P<0.001) for each coast and suggested that east coast snook grow faster than west coast snook. Common snook are protandric hermaphrodites. The gonads of 27 transitional specimens contained both degenerating spermatogenic and developing ovarian tissue, and sex reversal was observed in captive common snook. Common snook sex ratios and length-frequency distributions were also consistent with a diagnosis of protandric hermaphroditism. Females smaller than 500 mm FL were uncommon, and only one female less than 400 mm long was captured. The predicted lengths and ages at which 50% of the fish in the population would be females were 767 mm FL and 7.4 years for the east coast and 608 mm FL and 5.1 years for the west coast. Some males on both coasts were sexually mature at lengths less than 200 mm FL and at age 0; most age-1 males were mature on both coasts. All females were considered mature because they were derived from postspawning males. C1 Florida Marine Res Inst, Florida Fish & Wildlife Conservat Commiss, St Petersburg, FL 33701 USA. Florida Marine Res Inst, Florida Fish & Wildlife Conservat Commiss, Tequesta Field Lab, Tequesta, FL 33469 USA. Florida Marine Res Inst, Florida Fish & Wildlife Conservat Commiss, Stock Enhancement Res Facil, Port Manatee, FL 34221 USA. Natl Marine Fisheries Serv, St Petersburg, FL 33702 USA. RP Taylor, RG (reprint author), Florida Marine Res Inst, Florida Fish & Wildlife Conservat Commiss, 100 8th Ave SE, St Petersburg, FL 33701 USA. NR 26 TC 54 Z9 64 U1 4 U2 18 PU NATL MARINE FISHERIES SERVICE SCIENTIFIC PUBL OFFICE PI SEATTLE PA 7600 SAND POINT WAY NE BIN C15700, SEATTLE, WA 98115 USA SN 0090-0656 J9 FISH B-NOAA JI Fish. Bull. PD JUL PY 2000 VL 98 IS 3 BP 612 EP 624 PG 13 WC Fisheries SC Fisheries GA 341LT UT WOS:000088592400010 ER PT J AU Yoklavich, MM Greene, HG Cailliet, GM Sullivan, DE Lea, RN Love, MS AF Yoklavich, MM Greene, HG Cailliet, GM Sullivan, DE Lea, RN Love, MS TI Habitat associations of deep-water rockfishes in a submarine canyon: an example of a natural refuge SO FISHERY BULLETIN LA English DT Article ID BRITISH-COLUMBIA; REEF FISHES; PISCES-IV; SEBASTES; OREGON; SELECTION; ALASKA; AREAS; SHELF AB A multidisciplinary assessment of benthic rockfishes (genus Sebastes) and associated habitats in deep water was conducted in Sequel Submarine Canyon, Monterey Bay, California. Rock habitats at depths to 300 m were identified by using bathymetric and side-scan sonar imaging, verified by visual observations from a manned submersible, mapped and quantified. Species composition, abundance, size, and habitat specificity of fishes were determined by using a video camera and parallel laser system along transects made by a submersible. We counted 6208 nonschooling fishes representing at least 52 species from 83 10-min strip transects that covered an estimated 33,754 m(2). Rockfishes represented 77% of the total number of individuals, and included a minimum of 24 species, Six distinct habitat guilds of fishes were manifest from habitat-based clustering analysis: small species were associated with mud and cobble substrata of low relief, and larger species of rockfishes were associated with high-relief structures such as vertical rock walls, ridges, and boulder fields. There was remarkable concordance between some of the guilds identified in Sequel Canyon and the results of other habitat-specific assessments of fishes along the west coast of the United States from central California to Alaska. These generalities are valuable in predicting community structure and evaluating changes to that structure, as well as in applying small-scale species-habitat relationships to broader-scale fishery resource surveys. Additionally, establishment of these groups is critical when incorporating the concept of essential fish habitat (EFH), and negative impacts to it, into the management of fisheries in relatively deep water, as required by the Sustainable Fisheries Act of 1996. High numbers of large rockfishes (e.g. Sebastes chlorostictus. S. levis, S. rosenbblatti and S. ruberrimus) were locally associated with rock ledges, caves, and overhangs at sites having little or no evidence of fishing activity. Abundance and size of several species were lower at fished than at unfished sites. We suggest that rock outcrops of high relief interspersed with mud in deep water of narrow submarine canyons are less accessible to fishing activities and thereby can provide natural refuge for economically important fishes, as exemplified in Sequel Canyon. C1 NOAA, Pacific Fisheries Environm Lab, Natl Marine Fisheries Serv, Pacific Grove, CA 93950 USA. Moss Landing Marine Labs, Moss Landing, CA 95039 USA. Calif Dept Fish & Game, Monterey, CA 93940 USA. Univ Calif Santa Barbara, Inst Marine Sci, Santa Barbara, CA 93106 USA. RP Yoklavich, MM (reprint author), Natl Marine Fisheries Serv, Long Marine Lab, 100 Shaffer Rd, Santa Cruz, CA 95060 USA. NR 37 TC 125 Z9 125 U1 7 U2 24 PU NATL MARINE FISHERIES SERVICE SCIENTIFIC PUBL OFFICE PI SEATTLE PA 7600 SAND POINT WAY NE BIN C15700, SEATTLE, WA 98115 USA SN 0090-0656 J9 FISH B-NOAA JI Fish. Bull. PD JUL PY 2000 VL 98 IS 3 BP 625 EP 641 PG 17 WC Fisheries SC Fisheries GA 341LT UT WOS:000088592400011 ER PT J AU Bolden, SK AF Bolden, SK TI Long-distance movement of a Nassau grouper (Epinephelus striatus) to a spawning aggregation in the central Bahamas SO FISHERY BULLETIN LA English DT Article ID SERRANIDAE; PISCES; REPRODUCTION C1 NOAA, SE Fishery Sci Ctr, Natl Marine Fisheries Serv, Miami, FL 33133 USA. RP Bolden, SK (reprint author), NOAA, SE Fishery Sci Ctr, Natl Marine Fisheries Serv, 75 Virginia Beach Dr, Miami, FL 33133 USA. NR 12 TC 69 Z9 72 U1 1 U2 11 PU NATL MARINE FISHERIES SERVICE SCIENTIFIC PUBL OFFICE PI SEATTLE PA 7600 SAND POINT WAY NE BIN C15700, SEATTLE, WA 98115 USA SN 0090-0656 J9 FISH B-NOAA JI Fish. Bull. PD JUL PY 2000 VL 98 IS 3 BP 642 EP 645 PG 4 WC Fisheries SC Fisheries GA 341LT UT WOS:000088592400012 ER PT J AU Powell, AB Laban, EH Holt, SA Holt, GJ AF Powell, AB Laban, EH Holt, SA Holt, GJ TI Validation of age estimates from otoliths of larval and juvenile spotted seatrout, Cynoscion nebulosus SO FISHERY BULLETIN LA English DT Article ID SIZE-SELECTIVE MORTALITY; ATLANTIC MENHADEN; GROWTH; MICROSTRUCTURE; INCREMENTS; VARIABLES; FLOUNDER; SURVIVAL; PISCES; RIVER C1 NOAA, Ctr Coastal Fisheries & Habitat Res, Natl Ocean Serv, Beaufort, NC 28516 USA. Univ Texas, Inst Marine Sci, Port Aransas, TX 78373 USA. RP Powell, AB (reprint author), NOAA, Ctr Coastal Fisheries & Habitat Res, Natl Ocean Serv, 101 Pivers Isl Rd, Beaufort, NC 28516 USA. EM allyn.powell@noaa.gov NR 21 TC 8 Z9 8 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 JUL PY 2000 VL 98 IS 3 BP 650 EP 654 PG 5 WC Fisheries SC Fisheries GA 341LT UT WOS:000088592400014 ER PT J AU Brubaker, WW Schantz, MM Wise, SA AF Brubaker, WW Schantz, MM Wise, SA TI Determination of non-ortho polychlorinated biphenyls in environmental Standard Reference Materials SO FRESENIUS JOURNAL OF ANALYTICAL CHEMISTRY LA English DT Article ID DIBENZO-P-DIOXINS; PERFORMANCE LIQUID-CHROMATOGRAPHY; GAS-CHROMATOGRAPHY; MONO-ORTHO; SUBSTITUTED CHLOROBIPHENYLS; MASS-SPECTROMETRY; ISOTOPE-DILUTION; PCBS; CONGENERS; MARINE AB The concentrations of three non-ortho ("coplanar") polychlorinated biphenyls, 3,3',4,4'-tetrachlorobiphenyl (IUPAC PCB 77), 3,3',4,4',5-pentachlorobiphenyl (IUPAC PCB 126), and 3,3',4,4',5,5'-hexachlorobiphenyl (IUPAC PCB 169), were determined in five NIST Standard Reference Materials (SRMs) of environmental and biological interest. The measured levels were approximately between (0.2 to 1.3) ng/g in SRM 1588 a (Organics in Cod Liver Oil), (0.3 to 9) ng/g in SRM 1944 (New York/New Jersey Waterway Sediment), (0.2 to 0.4) ng/g in SRM 1945 (Organics in Whale Blubber), (1 to 18) ng/g in SRM 2974 (Organics in Freeze-dried Mussel Tissue [Mytilus edulis]), and (0.1 to 0.4) ng/g in candidate SRM 1946 (Lake Superior Fish Tissue). PCB 169 was present at < 0.1 ng/g in SRMs 1944 and 2974. C1 Natl Inst Stand & Technol, Div Analyt Chem, Gaithersburg, MD 20899 USA. RP Schantz, MM (reprint author), Natl Inst Stand & Technol, Div Analyt Chem, Gaithersburg, MD 20899 USA. NR 36 TC 9 Z9 9 U1 0 U2 2 PU SPRINGER-VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0937-0633 J9 FRESEN J ANAL CHEM JI Fresenius J. Anal. Chem. PD JUL PY 2000 VL 367 IS 5 BP 401 EP 406 PG 6 WC Chemistry, Analytical SC Chemistry GA 356CH UT WOS:000089426300002 PM 11227465 ER PT J AU Shimizu, M Swanson, P Fukada, H Hara, A Dickhoff, WW AF Shimizu, M Swanson, P Fukada, H Hara, A Dickhoff, WW TI Comparison of extraction methods and assay validation for salmon insulin-like growth factor-I using commercially available components SO GENERAL AND COMPARATIVE ENDOCRINOLOGY LA English DT Article DE insulin-like growth factor-I; radioimmunoassay; salmon; extraction; insulin-like growth factor-binding protein ID FACTOR-BINDING-PROTEINS; TROUT ONCORHYNCHUS-MYKISS; IGF-I; HOMOLOGOUS RADIOIMMUNOASSAY; BIOLOGICAL ACTIONS; COHO SALMON; RAT SERUM; PLASMA; SOMATOMEDIN; FISH AB Insulin-like growth factor-binding proteins (IGFBPs) may interfere with accurate measurement of plasma IGFs in radioimmunoassay (RIA), Although several simplified extraction methods for IGFs have been developed, these methods are not always validated for differing physiological states, developmental stages, and animal species. For teleost fish, neither the necessity of plasma extraction nor the validity of extraction methods for IGF RIA is widely established. We systematically examined the validity of acid-ethanol (AE) extraction, AE extraction followed by cryoprecipitation (AEC extraction), and SP-Sephadex extraction in RIA for salmon IGF-T using commercially available components (GroPep Pty Ltd). Displacement curves of plasma extracted by AE, AEC, and SP-Sephadex were parallel to those of the standard. Measured IGF-I levels in plasma from several developmental stages and under different physiological and experimental conditions were significantly increased by the extractions and comparable to those after acid-size exclusion chromatography (SEC). On Western ligand blotting using digoxigenin-labeled human IGF-I, the intensity of IGFBP bands remaining in plasma were reduced after extraction, although some IGFBPs remained. However, these residual IGFBPs did not interfere measurably with the RIA based on quantitative comparison of IGF-I levels with acid-SEC. We conclude that with this RIA extraction is necessary for measurement of salmon IGF-I in plasma since measured values were routinely lower in unextracted samples, and AE, AEC, and SP-Sephadex extractions are applicable to the IGF-I RIA using the commercially available components. Using the validated RIA for IGF-I, plasma IGF-I levels in nonmaturing and precociously maturing chinook salmon in spring were measured after AE extraction. During spring, nonmaturing and maturing fish fed and grew well, and plasma IGF-I level was significantly correlated with body weight in both fish. This result indicates that circulating IGF-I plays a key role in controlling growth in precociously maturing chinook salmon in spring as in nonmaturing fish. (C) 2000 Academic Press. C1 NOAA, Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, Seattle, WA 98112 USA. Univ Washington, Sch Fisheries, Seattle, WA 98195 USA. Hokkaido Univ, Fac Fisheries, Hakodate, Hokkaido 0418611, Japan. RP Shimizu, M (reprint author), NOAA, Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, 2725 Montlake Blvd E, Seattle, WA 98112 USA. NR 38 TC 133 Z9 133 U1 0 U2 14 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 JUL PY 2000 VL 119 IS 1 BP 26 EP 36 DI 10.1006/gcen.2000.7498 PG 11 WC Endocrinology & Metabolism SC Endocrinology & Metabolism GA 339YW UT WOS:000088506300004 PM 10882546 ER PT J AU Schaller, T Morford, J Emerson, SR Feely, RA AF Schaller, T Morford, J Emerson, SR Feely, RA TI Oxyanions in metalliferous sediments: Tracers for paleoseawater metal concentrations? SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Article ID EAST-PACIFIC-RISE; MID-ATLANTIC RIDGE; HYDROTHERMAL PLUME PARTICLES; DE-FUCA RIDGE; DISSOLVED PHOSPHATE; NAZCA PLATE; VENT FIELD; SEA-FLOOR; GEOCHEMISTRY; SEAWATER AB The concentration of carbon, Fe, Mn, S, P, V, Cr, As, Mo, Cd, U, and Re were determined in sediment core Y-71-7-53P near an active hydrothermal location on the southern East Pacific Rise crest (10 degreesS). The goal was to determine the usefulness of hydrothermal iron oxides as carriers of elemental tracers of seawater concentrations. The sediments are 70% carbonate and about 1.3% detrital material, with the remainder having a hydrothermal origin. Rhenium concentrations are at detrital levels suggesting little anaerobic diagenesis beyond manganese remobilization; however, U, Cd, and Mo concentrations all indicate alteration after deposition. Oxyanion/Fe ratios of P, V, and As in surface sediments are lower than the ratios in plume particles and covary with Fe content downcore. The probable explanation for these variations is variable efficiency of incorporation of these metals during iron oxide formation or early diagenetic processes after deposition. The P/Fe ratio in the core sediment is about half that in the plume particles. Among the oxyanion ratios, only the V/As ratio in the sediments is relatively constant at the present plume particle ratio during the past 60-70 kyr. Changes in sediments older than this could reflect variability in the incorporation efficiency or changes in V/As ratio in seawater. This study demonstrates the difficulties of using hydrothermal sediment element enrichments as tracers of past seawater chemistry changes. In this core it appears that all oxyanion ratios change for reasons other than seawater metal concentration changes, with the possible exception of the V/As ratio. Copyright (C) 2000 Elsevier Science Ltd. C1 Univ Washington, Sch Oceanog, Seattle, WA 98195 USA. NOAA, Pacific Marine Environm Lab, Seattle, WA 98115 USA. RP Morford, J (reprint author), Univ Washington, Sch Oceanog, Seattle, WA 98195 USA. OI Morford, Jennifer/0000-0003-4882-6576 NR 64 TC 11 Z9 11 U1 0 U2 10 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0016-7037 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD JUL PY 2000 VL 64 IS 13 BP 2243 EP 2254 DI 10.1016/S0016-7037(99)00443-3 PG 12 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 409TJ UT WOS:000167401500006 ER PT J AU Heckman, G AF Heckman, G TI NOAA space weather alerts - Response SO HEALTH PHYSICS LA English DT Letter C1 NOAA, Environm Res Labs, Space Environm Ctr, Boulder, CO 80303 USA. NR 0 TC 1 Z9 1 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 JUL PY 2000 VL 79 IS 1 BP 86 EP 87 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 323ND UT WOS:000087570700015 ER PT J AU Ellis, MW Fanney, AH Davis, MW AF Ellis, MW Fanney, AH Davis, MW TI Calibration of a calorimeter for thermal resistance measurements of advanced insulation panels SO HVAC&R RESEARCH LA English DT Article AB Insulation technologies are being developed to reduce the energy consumption associated with refrigerators, freezers, and the transport of refrigerated products. Among the insulation concepts being explored are powder, foam, glass-fiber-filled evacuated panels, and low-conductivity gas-filled panels. These advanced insulation panels offer the potential for significant reductions in energy consumption and greater flexibility in product design. Unfortunately, the equipment used to determine the thermal resistance of traditional building insulation materials is not well suited for measuring the thermal resistance of advanced insulation panels. This paper describes a calorimetric apparatus to measure the thermal resistance of advanced insulation materials. It presents the procedures used to determine the thermal resistance of advanced insulation panels, and compares the calorimetric results to measurements from the guarded hot plate for extruded polystyrene specimens. The measurements agree to within 3% over a mean temperature range of 280 to 295 K. C1 Virginia Polytech Inst & State Univ, Dept Mech Engn, Blacksburg, VA 24061 USA. Natl Inst Stand & Technol, Heat Transfer & Alternat Energy Syst Grp, Bldg Environm Div, Gaithersburg, MD 20899 USA. RP Ellis, MW (reprint author), Virginia Polytech Inst & State Univ, Dept Mech Engn, Blacksburg, VA 24061 USA. RI Ellis, Michael/M-5405-2014 NR 13 TC 19 Z9 19 U1 0 U2 2 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 JUL PY 2000 VL 6 IS 3 BP 273 EP 284 DI 10.1080/10789669.2000.10391263 PG 12 WC Thermodynamics; Construction & Building Technology; Engineering, Mechanical SC Thermodynamics; Construction & Building Technology; Engineering GA 342KP UT WOS:000088644000006 ER PT J AU Henson, WK Yang, N Kubicek, S Vogel, EM Wortman, JJ De Meyer, K Naem, A AF Henson, WK Yang, N Kubicek, S Vogel, EM Wortman, JJ De Meyer, K Naem, A TI Analysis of leakage currents and impact on off-state power consumption for CMOS technology in the 100-nm regime SO IEEE TRANSACTIONS ON ELECTRON DEVICES LA English DT Article DE MOS devices; off-state leakage; power consumption; ultrathin gate oxide ID CAPACITANCE-VOLTAGE MEASUREMENTS; ULTRATHIN GATE OXIDES; TUNNELING CURRENT; INVERSION LAYER; MOS DEVICES; MOSFETS AB Off-state leakage currents have been investigated for sub-100 nm CMOS technology. The two leakage mechanisms investigated in this work include conventional off-state leakage due to short channel effects and gate leakage through ultrathin gate oxides. The conventional off-state leakage due to short channel effects exhibited the similar characteristics as previously published; however, gate leakage introduces two significant consequences with respect to off-state power consumption: 1) an increase in the number of transistors contributing to the total off-state power consumption of the chip and 2) an increase in the conventional off-state current due to gate leakage near the drain region of the device. Using experimentally measured data, it is estimated that gate leakage does not exceed the off-state specifications of the National Technology Roadmap for Semiconductors for gate oxides as thin as 1.4 to 1.5 nm for high performance CMOS. Low power and memory applications may be limited to an oxide thickness of 1.8 to 2.0 nm in order to minimize the off-state power consumption and maintain an acceptable level of charge retention. The analysis in this work suggests that reliability will probably limit silicon oxide scaling for high performance applications whereas gate leakage will limit gate oxide scaling for low power and memory applications. C1 Interuniv Microelect Ctr, B-3001 Louvain, Belgium. Adv Micro Devices Inc, Sunnyvale, CA 94088 USA. Natl Inst Stand & Technol, Div Semicond Elect, Gaithersburg, MD 20899 USA. N Carolina State Univ, Dept Elect & Comp Engn, Raleigh, NC 27695 USA. Natl Semicond Corp, Santa Clara, CA 95052 USA. RP Henson, WK (reprint author), Interuniv Microelect Ctr, B-3001 Louvain, Belgium. RI Vogel, Eric/A-7731-2008 OI Vogel, Eric/0000-0002-6110-1361 NR 33 TC 55 Z9 56 U1 1 U2 4 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9383 J9 IEEE T ELECTRON DEV JI IEEE Trans. Electron Devices PD JUL PY 2000 VL 47 IS 7 BP 1393 EP 1400 DI 10.1109/16.848282 PG 8 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA 329GH UT WOS:000087898500015 ER PT J AU Quilfen, Y Bentamy, A Delecluse, P Katsaros, K Grima, N AF Quilfen, Y Bentamy, A Delecluse, P Katsaros, K Grima, N TI Prediction of sea level anomalies using ocean circulation model forced by scatterometer wind and validation using TOPEX/Poseidon data SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE ocean model; ocean surface; scatterometer; sea level ID ORTHOGONAL FUNCTION-ANALYSIS; WESTERN EQUATORIAL PACIFIC; TROPICAL ATLANTIC-OCEAN; SATELLITE SCATTEROMETER; SURFACE TEMPERATURE; INDIAN-OCEAN; VARIABILITY; SENSITIVITY; SIMULATION; GEOSAT AB Uncertainties in the surface wind field have long been recognized as a major limitation in the interpretation of results obtained by oceanic circulation models. It is especially true in the tropical oceans, where the response to wind forcing is very strong on short time scales. The purpose of this paper is to show that these uncertainties can be greatly reduced by using spaceborne wind sensors that provide accurate measurements on a global basis. Surface winds over the global oceans have been measured by scatterometry since the launch of the European Remote Sensing Satellite (ERS-1) in August 1991 by the European Space Agency, Noordwijk, The Netherlands, and is currently provided by ERS-2, launched in April 1995. The ground track wind vectors are processed to compute mean weekly surface winds onto a 1 degrees square grid at the Institut Francais de Recherche pour 1'Exploitation de la Mer (IFREMER), Plouzane, France. These winds are validated by comparison with the buoy array in the tropical Pacific ocean, showing good agreement. In order to further evaluate this wind field, the three dimensional (3-D) ocean model OPA7 developed at Laboratoire d'Oceanographie Dynamique et de Climatologie, Paris, Prance, is forced over the tropical oceans by the ERS-derived wind stress fields and by fields from the atmospheric model Arpege/Climat. Selected ocean parameters are defined in order to validate the ocean model results with measurements of the tropical ocean and global atmosphere (TOGA) buoys in the Pacific ocean. The ability of the model to describe the short scale (a few weeks to a few years) oceanic variability is greatly enhanced when the satellite-derived surface forcing is used. In this paper, we present further comparison of the ocean model results with the TOPEX-Poseidon altimeter measurements. Simulated and measured sea level variability are described over the three tropical oceans. The annual and semi-annual signals, as well as the interannual variability, partly linked to the El Nino southern oscillation (ENSO) phenomenon, are well simulated by the OPA7 model when the satellite winds are used. Furthermore, it shows that the objective method, kriging technique, used to interpolate the mean ERS wind fields, dramatically reduces the effects of the satellite bandlike sampling. In the last part of this paper, we focus on the relationship between the wind stress anomalies and the sea level anomalies in the case of the 1997-1998 El Nino event. It clearly shows that sea level anomalies in the eastern and western parts of the Pacific are strongly linked to wind stress anomalies in the central Pacific. The forthcoming scatterometers aboard the METOP and ADEOS satellites will provide a much better coverage. It will enable the wind variability spatial and temporal scares to be resolved better, in order that wind uncertainties no longer blur the interpretation of ocean circulation numerical models results. C1 IFREMER, F-29280 Plouzane, France. CNRS, Paris, France. Natl Ocean & Atmopher Adm, Atlantic Oceanog & Meteorol Lab, Miami, FL 33167 USA. RP IFREMER, BP 70, F-29280 Plouzane, France. EM yquilfen@ifremer.fr RI Grima, Nicolas/N-3252-2014; Quilfen, Yves/A-1824-2016 OI Grima, Nicolas/0000-0002-1607-8975; NR 38 TC 15 Z9 15 U1 0 U2 3 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 0196-2892 EI 1558-0644 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD JUL PY 2000 VL 38 IS 4 BP 1871 EP 1884 DI 10.1109/36.851770 PN 2 PG 14 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 337TM UT WOS:000088377800012 ER PT J AU Connor, LN Chang, PS AF Connor, LN Chang, PS TI Ocean surface wind retrievals using the TRMM microwave imager SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE microwave radiometry; sea surface wind; TRMM microwave imager; tropical rainfall measuring mission (TRMM) ID SENSOR; RAINFALL; SSM/I AB An analysis of one year of brightness temperature data from the TRMM microwave imager (TMI) is presented with regard to the retrieval of ocean surface wind speeds using standard regression techniques with in situ meteorological buoy measurements. Comparisons to similar satellite radiometer data from the special sensor microwave/imager (SSM/I) are also presented to help quantify atmospheric contributions to the surface wind retrievals. Particular emphasis is placed upon the use of the 10.7 GHz channels aboard the TMI in overcoming the contamination in the ocean surface brightness temperature measurements caused by precipitation and water vapor in the propagation path. The resulting wind retrieval improvements permit a relaxation in the rain flag definitions used to determine precipitation interference cutoff criteria, allowing accurate wind speed retrievals over a wider range of precipitation conditions. These improvements are realized through the construction of a new D-matrix wind speed retrieval algorithm suitable for the middle and low latitude coverage provided by the TRMM orbit. C1 Univ Corp Atmospher Res Visiting Scientist Progra, Camp Springs, MD 20746 USA. NOAA, Natl Environm Satellite Data & Informat Serv, Off Res & Applicat, Camp Springs, MD 20746 USA. RP Connor, LN (reprint author), Univ Corp Atmospher Res Visiting Scientist Progra, Camp Springs, MD 20746 USA. RI Chang, Paul/F-5580-2010; Connor, Laurence/E-7930-2011 OI Chang, Paul/0000-0001-5113-0938; Connor, Laurence/0000-0002-5276-6257 NR 9 TC 20 Z9 22 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 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD JUL PY 2000 VL 38 IS 4 BP 2009 EP 2016 DI 10.1109/36.851782 PN 2 PG 8 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 337TM UT WOS:000088377800024 ER PT J AU Palmer, AJ Fairall, CW Brewer, WA AF Palmer, AJ Fairall, CW Brewer, WA TI Complexity in the atmosphere SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE atmospheric turbulence; chaos and complexity; nonlinear dynamics ID STATISTICAL COMPLEXITY; COMPUTATION AB Two complexity measures, mutual information and statistical complexity, were applied to two types of atmospheric turbulence data sets. One data set is time series measurements of ocean surface winds, The other is a time-height, Doppler lidar image of vertical winds in the atmosphere. High values of complexity are seen where they might be expected: in the time series data in wind regimes where statistical models of turbulence perform poorly and in the time-height Doppler lidar images at the top of the boundary layer, where the atmosphere is undergoing a transition from an unstable to a stable flow regime. Finite-state machines known as "epsilon machines" were constructed to model the information flow in the data. The results are a step toward establishing ne iv, unbiased, modeling frameworks for atmospheric turbulence that will make optimal use of the computational resources being applied to sensing, data management, and numerical modeling of the atmosphere. C1 NOAA, Environm Technol Lab, Boulder, CO 80303 USA. RP Palmer, AJ (reprint author), NOAA, Environm Technol Lab, Boulder, CO 80303 USA. RI Brewer, Wm Alan/I-3920-2013 NR 17 TC 11 Z9 13 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 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD JUL PY 2000 VL 38 IS 4 BP 2056 EP 2063 DI 10.1109/36.851786 PN 2 PG 8 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 337TM UT WOS:000088377800028 ER PT J AU Della Torre, E Fry, RA Alejos, O Cardelli, E AF Della Torre, E Fry, RA Alejos, O Cardelli, E TI Identification of parameters in multilayer media SO IEEE TRANSACTIONS ON MAGNETICS LA English DT Article; Proceedings Paper CT 12th Conference on the Computation of Electromagnetic Fields (COMPUMAG 99) CY OCT 25-28, 1999 CL SAPPORO, JAPAN SP Int Compumag Soc, Hokkaido Univ, IEE Japan, Japan Soc Appl Electromagnet & Mech, Hokkaido Univ, Ctr Adv Sci & Technol DE identification; magnetic materials; Preisach modeling; scalar hysteresis ID PREISACH MODEL; MAGNETIZATION AB Multilayer media are of increasing importance as magneto-optic and perpendicular media. The properties of successive layers evolve as the layers are epitaxially deposited, This complicates both the model for these media and the identification of the model parameters. In this paper, the effect of the variation of the Preisach model parameters is discussed and an identification procedure is outlined. Reentrant-type hysteresis behavior, which is found to be necessary in order to accurately fit both major loop and first-order reversal curves in these multilayer materials, is also considered. C1 George Washington Univ, Dept Elect Engn & Comp Engn, Washington, DC 20052 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Univ Perugia, Dept Ind Engn, I-06125 Perugia, Italy. RP George Washington Univ, Dept Elect Engn & Comp Engn, Washington, DC 20052 USA. EM dellator@seas.gwu.edu; richard.fry@nist.gov RI Alejos, Oscar/K-5745-2014 NR 7 TC 6 Z9 6 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 0018-9464 EI 1941-0069 J9 IEEE T MAGN JI IEEE Trans. Magn. PD JUL PY 2000 VL 36 IS 4 BP 1272 EP 1275 DI 10.1109/20.877672 PN 1 PG 4 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA 367NG UT WOS:000090067900145 ER PT J AU Gutta, S Huang, JRJ Jonathon, P Wechsler, H AF Gutta, S Huang, JRJ Jonathon, P Wechsler, H TI Mixture of experts for classification of gender, ethnic origin, and pose of human faces SO IEEE TRANSACTIONS ON NEURAL NETWORKS LA English DT Article DE decision trees (DT); ensembles of radial basis functions (ERBF) ethnic classification; face processing; FERET; gating networks; gender classification; mixtures of experts; pose discrimination; radial basis functions (RBF's) kernels; support vector machines (SVMs) ID RECOGNITION ALGORITHMS; CLASSIFIERS; DIFFERENCE; SEX AB In this paper we describe the application of mixtures of experts on gender and ethnic classification of human faces, and Dose classification, and show their feasibility on the FERET database of facial images. The FERET database allows us to demonstrate performance on hundreds or thousands of images. The mixture of experts is implemented using the "divide and conquer" modularity principle with respect to the granularity and/or the locality of information, The mixture of experts consists of ensembles of radial basis functions (RBFs), Inductive decision trees (DTs) and support vector machines (SVMs) implement the "gating network" components for deciding which of the experts should be used to determine the classification output and to restrict the support of the input space. Both the ensemble of RBF's (ERBF) and SVM use the RBF kernel ("expert") for gating the inputs. Our experimental results yield an average accuracy rate of 96% on gender classification and 92% on ethnic classification using the ERBF/DT approach from frontal face images, while the SVM yield 100% on pose classification. C1 Philips Res Labs, Briarcliff Manor, NY 10510 USA. George Mason Univ, Dept Comp Sci, Fairfax, VA 22030 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Gutta, S (reprint author), Philips Res Labs, Briarcliff Manor, NY 10510 USA. NR 48 TC 86 Z9 91 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 1045-9227 J9 IEEE T NEURAL NETWOR JI IEEE Trans. Neural Netw. PD JUL PY 2000 VL 11 IS 4 BP 948 EP 960 DI 10.1109/72.857774 PG 13 WC Computer Science, Artificial Intelligence; Computer Science, Hardware & Architecture; Computer Science, Theory & Methods; Engineering, Electrical & Electronic SC Computer Science; Engineering GA 343TC UT WOS:000088716800011 PM 18249821 ER PT J AU Kirov, SM Barnett, TC Pepe, CM Strom, MS Albert, MJ AF Kirov, SM Barnett, TC Pepe, CM Strom, MS Albert, MJ TI Investigation of the role of type IV Aeromonas pilus (Tap) in the pathogenesis of Aeromonas gastrointestinal infection SO INFECTION AND IMMUNITY LA English DT Article ID GRAM-NEGATIVE BACTERIA; EXTRACELLULAR PROTEIN SECRETION; POSSIBLE COLONIZATION FACTOR; PSEUDOMONAS-AERUGINOSA PILI; HEMOLYTIC-UREMIC SYNDROME; CHOLERAE O139 BENGAL; VIBRIO-CHOLERAE; GENE-CLUSTER; EL-TOR; FUNCTIONAL-CHARACTERIZATION AB Although there is substantial evidence that type IV pili purified from diarrhea-associated Aeromonas species (designated Bfp for bundle forming pilus) are intestinal colonization factors (S. M. Kirov, L. A. O'Donovan, and K. Sanderson, Infect. Immun, 67:5447-5454, 1999), nothing is known regarding the function of a second family of Aeromonas type IV pili (designated Tap for type IV Aeromonas pilus), identified following the cloning of a pilus biogenesis gene cluster tapABCD. Related pilus gene clusters are widely conserved among gram-negative bacteria, but their significance for virulence has been controversial. To investigate the role of Tap pili in Aeromonas pathogenesis, mutants of Aeromonas strains (a fish isolate of A. hydrophila and a human dysenteric isolate of A. veronii bv. sobria) were prepared hy insertional inactivation of the tapA gene which encodes the type IV pilus subunit protein, TapA, Exotoxic activities were unaffected by the mutation in tapA. Inactivation of tapA had no effect on the bacterial adherence of these two isolates to HEp-2 cells. For the A. veronii bv. sobria isolate, adhesion to Henle 407 intestinal cells and to human intestinal tissue was also unaffected. There was no significant effect on the duration of colonization or incidence of diarrhea when the A. veronii bv. sobria strain was tested in the removable intestinal tie adult rabbit diarrhea model or on its ability to colonize infant mice. Evidence was obtained that demonstrated that TapA was expressed by both Aeromonas species and was present on the cell surface, although if assembled into pili this pilus type appears to be an uncommon one under standard bacterial growth conditions. Further studies into factors which may influence Tap expression are required, but the present study suggests that Tap pili may not be as significant as Bfp pili for Aeromonas intestinal colonization. C1 Univ Tasmania, Discipline Pathol, Hobart, Tas 7001, Australia. NOAA, Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, US Dept Commerce, Seattle, WA 98112 USA. Int Ctr Diarrhoeal Dis Res, Div Sci Lab, Dhaka 1000, Bangladesh. RP Kirov, SM (reprint author), Univ Tasmania, Discipline Pathol, GPO Box 252-29, Hobart, Tas 7001, Australia. RI Barnett, Tim/G-2155-2011 NR 52 TC 27 Z9 29 U1 0 U2 2 PU AMER SOC MICROBIOLOGY PI WASHINGTON PA 1752 N ST NW, WASHINGTON, DC 20036-2904 USA SN 0019-9567 J9 INFECT IMMUN JI Infect. Immun. PD JUL PY 2000 VL 68 IS 7 BP 4040 EP 4048 DI 10.1128/IAI.68.7.4040-4048.2000 PG 9 WC Immunology; Infectious Diseases SC Immunology; Infectious Diseases GA 326AT UT WOS:000087710200035 PM 10858220 ER PT J AU Hurly, JJ AF Hurly, JJ TI Thermophysical properties of gaseous HBr and BCl3 from speed-of-sound measurements SO INTERNATIONAL JOURNAL OF THERMOPHYSICS LA English DT Article DE BCl3; boron trichloride; equation of state; HBr; hydrogen bromide; speed of sound; thermodynamic properties; transport properties; virial coefficients ID THERMODYNAMIC PROPERTIES; ACOUSTIC MEASUREMENTS; VIRIAL-COEFFICIENTS AB The speed of sound in gaseous hydrogen bromide (HBr) and boron trichloride (BCl3) was measured using a highly precise acoustic resonance technique. The HBr speed-of-sound measurements span the temperature range 230 to 440 K and the pressure range from 0.05 to 1.5 MPa. The BCl3 speed-of-sound measurements span the temperature range 290 to 460 K and the pressure range from 0.05 MPa to 0.40 MPa. The pressure range in each fluid was limited to 80% of the sample vapor pressure at each temperature. The speed-of-sound data have a relative standard uncertainty of 0.01%. The data were analyzed to obtain the ideal-gas heat capacities as a function of temperature with a relative standard uncertainty of 0.1%. The heat capacities agree with those calculated from spectroscopic data within their combined uncertainties. The speeds of sound were fitted with the virial equation of state to obtain the temperature-dependent density virial coefficients. Two virial coefficient models were employed, one based on the hard-core square-well intermolecular potential model and the second based on the hard-core Lennard-Jones intermolecular potential model. The resulting virial equations of state reproduced the speed-of-sound measurements to 0.01% and can be expected to calculate vapor densities with a relative standard uncertainty of 0.1%. Transport properties calculated from the hard-core Lennard-Jones potential model should have a relative standard uncertainty of 10% or less. C1 Natl Inst Stand & Technol, Chem Sci & Technol Lab, Phys & Chem Properties Div, Gaithersburg, MD 20899 USA. RP Hurly, JJ (reprint author), Natl Inst Stand & Technol, Chem Sci & Technol Lab, Phys & Chem Properties Div, Gaithersburg, MD 20899 USA. NR 44 TC 11 Z9 11 U1 1 U2 4 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 JUL PY 2000 VL 21 IS 4 BP 805 EP 829 DI 10.1023/A:1006627306105 PG 25 WC Thermodynamics; Chemistry, Physical; Mechanics; Physics, Applied SC Thermodynamics; Chemistry; Mechanics; Physics GA 362EP UT WOS:000089765900001 ER PT J AU Basak, D Kattner, UR McClure, JL Josell, D Cezairliyan, A AF Basak, D Kattner, UR McClure, JL Josell, D Cezairliyan, A TI Application of laser polarimetry to the measurement of specific heat capacity and enthalpy of the alloy 53Nb-47Ti (mass %) in the temperature range 1600 to 2000 K by a millisecond-resolution pulse heating technique SO INTERNATIONAL JOURNAL OF THERMOPHYSICS LA English DT Article DE electrical resistivity; enthalpy; high temperature; laser polarimetry; Nb-Ti alloy; pulse heating; specific heat capacity ID MOLYBDENUM; EMISSIVITY; TI AB The determination of the specific heat capacity, enthalpy, and electrical resistivity of the alloy 53Nb-47Ti (mass%) in the temperature range 1600 to 2000 K is described. The method is based on rapid resistive self-heating of a solid cylindrical specimen from room temperature to the maximum temperature of interest by the passage of a subsecond-duration electric current pulse through the specimen and on simultaneously measuring the pertinent experimental quantities. The experimental quantities measured are the current through the specimen, voltage drop across the effective specimen, specimen radiance temperature at two wave-lengths, and normal spectral emissivity of the specimen. The present study extends this technique, previously applied to pure metals, to the determination of specific heat capacity and enthalpy of the alloy, 53Nb-47Ti. The measured properties were compared to those calculated from a thermodynamic description of the Nb-Ti system. C1 Natl Inst Stand & Technol, Div Met, Gaithersburg, MD 20899 USA. RP Basak, D (reprint author), Natl Inst Stand & Technol, Div Met, Gaithersburg, MD 20899 USA. NR 14 TC 11 Z9 11 U1 1 U2 4 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 JUL PY 2000 VL 21 IS 4 BP 913 EP 926 DI 10.1023/A:1006618425669 PG 14 WC Thermodynamics; Chemistry, Physical; Mechanics; Physics, Applied SC Thermodynamics; Chemistry; Mechanics; Physics GA 362EP UT WOS:000089765900008 ER PT J AU Begley, EF Sturrock, CP AF Begley, EF Sturrock, CP TI MatML: An XML for standardizing web-based materials property data SO JOM-JOURNAL OF THE MINERALS METALS & MATERIALS SOCIETY LA English DT Article C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU MINERALS METALS MATERIALS SOC PI WARRENDALE PA 420 COMMONWEALTH DR, WARRENDALE, PA 15086 USA SN 1047-4838 J9 JOM-J MIN MET MAT S JI JOM-J. Miner. Met. Mater. Soc. PD JUL PY 2000 VL 52 IS 7 BP 56 EP 56 DI 10.1007/s11837-000-0164-3 PG 1 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Mineralogy; Mining & Mineral Processing SC Materials Science; Metallurgy & Metallurgical Engineering; Mineralogy; Mining & Mineral Processing GA 335GF UT WOS:000088235200010 ER PT J AU Krajewski, WF Ciach, GJ McCollum, JR Bacotiu, C AF Krajewski, WF Ciach, GJ McCollum, JR Bacotiu, C TI Initial validation of the global precipitation climatology project monthly rainfall over the United States SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID UNCERTAINTY; ERROR AB The Global Precipitation Climatology Project (GPCP) established a multiyear global dataset of satellite-based estimates of monthly rainfall accumulations averaged over a grid of 2.5 degrees x 2.5 degrees geographical boxes. This paper describes an attempt to quantify the error variance of these estimates at selected reference sites. Fourteen reference sites were selected over the United Stares at the GPCP grid locations where high-density rain gauge network and high-quality data are available. A rigorous methodology for estimation of the error statistics of the reference sites was applied. A method of separating the reference error variance from the observed mean square difference between the reference and the GPCP products was proposed and discussed. As a result, estimates of the error variance of the GPCP products were obtained. Two kinds of GPCP products were evaluated: 1) satellite-only products, and 2) merged products that incorporate some rain gauge data that were available to the project. The error analysis results show that the merged product is characterized by smaller errors, both in terms of bias as well as the random component. The bias is, on average, 0.88 for the merged product and 0.70 for the satellite-only product. The average random component is 21% for the merged product and 79% for the satellite-only product. The random error is worse in the winter than in the summer. The error estimates agree well with their counterparts produced by the GPCP. C1 Univ Iowa, Iowa Inst Hydraul Res, Iowa City, IA 52242 USA. Inst Meteorol & Water Management, Warsaw, Poland. NOAA, NESDIS, Off Res & Applicat, Camp Springs, MD USA. RP Krajewski, WF (reprint author), Univ Iowa, Iowa Inst Hydraul Res, Iowa City, IA 52242 USA. EM wkrajew@engineering.uiowa.edu NR 20 TC 69 Z9 69 U1 2 U2 14 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8763 J9 J APPL METEOROL JI J. Appl. Meteorol. PD JUL PY 2000 VL 39 IS 7 BP 1071 EP 1086 DI 10.1175/1520-0450(2000)039<1071:IVOTGP>2.0.CO;2 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 342CE UT WOS:000088627000009 ER PT J AU Crawford, TM Bluestein, HB AF Crawford, TM Bluestein, HB TI An operational, diagnostic surface energy budget model SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID ATMOSPHERIC RADIATION; BOUNDARY-LAYER; UNITED-STATES; PARAMETERIZATION; FLUXES; LAND; VARIABILITY; EMISSIVITY; MESONET; SCHEMES AB In recent years, there has been a growing appreciation of the importance of land-atmosphere interactions in determining the state of the boundary layer To examine this phenomenon in more detail, a new technique has been developed to evaluate the surface energy budget during the daytime from standard meteorological observations. Using only Oklahoma Mesonetwork (Mesonet) data at 5- and 30-min intervals as input, the technique calculates net radiation (R-n), ground heat flux (G), and latent heat Bur (LE). The sensible heat flux (H) is calculated as a residual. The R-n term is calculated using observed values of downwelling shortwave radiation, an improved method of estimating downwelling longwave radiation, and simple parameterizations of upwelling shortwave and longwave radiation. The modeled values of R-n are unbiased and are consistently within 25 W m(-2) of observed values. Ground heat flux, which is the combination of a 5-cm soil flux term and a storage term, was difficult to verify without prior knowledge of vegetation height. Latent heat Bur is calculated from the Penman-Monteith equation, in which surface resistance is estimated. Using data from the Atmospheric Radiation Measurement Program, simple parameterizations were developed (one each for eastern and western Oklahoma) for this term, based on observations of temperature, relative humidity, solar radiation, soil moisture, and estimates of leaf age. Net radiation and G are calculated, and then their sum is partitioned into H and LE. Because there were no observations of LE at the Mesonet sites, the preexisting reliable estimates of H were used to verify the new estimates of both H and LE. Because there were problems with the soil moisture data from some of the sites, data from only two Mesonet sites were available for verification. The estimates of H were unbiased and within 60 W m(-2) (rmse) at the sites in both eastern and western Oklahoma. Because of the limited verification data currently available, the model results are preliminary and in need of further testing. C1 Univ Oklahoma, Sch Meteorol, Norman, OK 73019 USA. RP Natl Severe Storms Lab, Cooperat Inst Mesoscale Meteorol Studies, 1313 Halley Circle, Norman, OK 73069 USA. EM tcrawford@ou.edu NR 50 TC 5 Z9 5 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 JUL PY 2000 VL 39 IS 7 BP 1196 EP 1217 DI 10.1175/1520-0450(2000)039<1196:AODSEB>2.0.CO;2 PG 22 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 342CE UT WOS:000088627000018 ER PT J AU Troyanchuk, IO Khalyavin, DD Lynn, JW Erwin, RW Huang, Q Szymczak, H Szymczak, R Baran, M AF Troyanchuk, IO Khalyavin, DD Lynn, JW Erwin, RW Huang, Q Szymczak, H Szymczak, R Baran, M TI Magnetic phase diagrams of the Ln(Mn1-xCox)O-3 (Ln=Eu, Nd, Y) systems SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID PEROVSKITES; MN-55 AB We report magnetization measurements in the Ln(Mn1-xCox)O3+lambda (Ln=Eu, Nd; 0 less than or equal to x < 1) and Y(Mn1-xCox)O-3 (0.35 less than or equal to x less than or equal to 0.5) perovskites as a function of temperature and magnetic field. Compositions in the range of 0.35 less than or equal to x less than or equal to 0.8 (Ln=Eu), 0.4 less than or equal to x less than or equal to 0.6 (Ln=Nd), and 0.35 less than or equal to x less than or equal to 0.45 (Ln=Y) exhibit metamagnetic behavior associated with a transformation of the magnetic structure from ferrimagnetic, where the magnetic moments of Co2+ and Mn4+ ions are antiparallel, to ferromagnetic where they are parallel. A ferromagnetic state is observed for the 0.1 less than or equal to x less than or equal to 0.15 (Ln=Nd) and 0.45 < x less than or equal to 0.5 (Ln=Y) compositions. Doping and H-T phase diagrams are presented, and these diagrams resemble those of Ln(1-x)Ca(x)MnO(3) charge-ordered manganites. Neutron diffraction studies indicate site ordering of the Co and Mn ions in the Y(Co0.5Mn0.5)O-3 system, which is presumably responsible for its ferromagnetic behavior. (C) 2000 American Institute of Physics. [S0021-8979(00)01510-3]. C1 Natl Acad Sci Belarus, Inst Solid State & Semicond Phys, Minsk 220072, Byelarus. Natl Inst Stand & Technol, Ctr Neutron Res, Gaithersburg, MD 20899 USA. Univ Maryland, Dept Mat & Nucl Engn, College Pk, MD 20742 USA. Polish Acad Sci, Inst Phys, PL-02668 Warsaw, Poland. RP Troyanchuk, IO (reprint author), Natl Acad Sci Belarus, Inst Solid State & Semicond Phys, P Brovki Str 17, Minsk 220072, Byelarus. RI Khalyavin, Dmitry/E-4335-2017 OI Khalyavin, Dmitry/0000-0002-6724-7695 NR 13 TC 22 Z9 22 U1 0 U2 8 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD JUL 1 PY 2000 VL 88 IS 1 BP 360 EP 367 DI 10.1063/1.373668 PG 8 WC Physics, Applied SC Physics GA 325YE UT WOS:000087704000057 ER PT J AU Snider, JB AF Snider, JB TI Long-term observations of cloud liquid, water vapor, and cloud-base temperature in the North Atlantic Ocean SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article ID RADIOMETER AB Measurements of precipitable water vapor, cloud liquid, and cloud-base temperature made at Porto Santo Island, Madeira Archipelago, are presented. The observations were made continuously over a 1-yr period from July 1992 to June 1993. Instrumentation consisted of a 20- and 31-GHz ground-based microwave radiometer for measurement of water vapor and cloud liquid, and a 10.7-mu m infrared radiometer for measurement of cloud-base temperature, A statistical summary of the data is presented for clear and cloudy conditions, considered both separately and combined. The mean and variance of precipitable water vapor are smaller during clear than during cloudy periods. Values of water vapor during the winter are 26% smaller than during summer months. The mean decorrelation time of precipitable water vapor is generally found to be less than 12 h. C1 Univ Colorado, NOAA, Cooperat Inst Res Environm Sci, Boulder, CO 80303 USA. RP Snider, JB (reprint author), Univ Colorado, NOAA, Cooperat Inst Res Environm Sci, R-E-ET6,325 Broadway, Boulder, CO 80303 USA. NR 5 TC 4 Z9 6 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 JUL PY 2000 VL 17 IS 7 BP 928 EP 939 DI 10.1175/1520-0426(2000)017<0928:LTOOCL>2.0.CO;2 PG 12 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA 336RC UT WOS:000088315900004 ER PT J AU Williams, CR Ecklund, WL Johnston, PE Gage, KS AF Williams, CR Ecklund, WL Johnston, PE Gage, KS TI Cluster analysis techniques to separate air motion and hydrometeors in vertical incident profiler observations SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article ID WIND PROFILERS; IDENTIFICATION; REFLECTIVITY; VELOCITIES; SCATTERING; CLOUD AB Profilers operating in the UHF range are sensitive to both Bragg scattering from radio refractive index structure and to Rayleigh scattering from small point targets. Identification of the scattering process is critical for proper interpretation of these observations, especially the data collected from the vertical incident beam. This study evaluates the performance of Doppler velocity thresholds as a means to separate air motions from hydrometeor motions in vertical incident profiler observations. This evaluation consists of three different steps. First, using two collocated profilers operating at different frequencies, the observations are unambiguously identified as Bragg or Rayleigh scattering processes. Second, the observations are separated into either air or hydrometeor motion using only the data from one profiler. The third step quantitatively evaluates the performance of the single profiler separation techniques by counting the number of correct classifications and adjusting the count by the number of incorrect classifications. Constant Doppler velocity threshold methods are acceptable methods to separate air motions from hydrometeor motions only after the correct threshold is determined. This study presents a cluster analysis method that robustly and objectively separates air from hydrometeor motions. The introduced cluster analysis produces two thresholds. The first threshold is a Doppler velocity threshold that is a Function of reflectivity. The second threshold is the maximum reflectivity in which the Doppler velocity threshold divides the observations into two statistical distributions using the Kolmogorov-Smirnov statistical test. The cluster analysis method quantitatively performs better than constant Doppler velocity threshold methods, and is a repeatable, self-adapting, statistically based procedure. C1 NOAA, CIRES, Aeron Lab, Boulder, CO 80303 USA. Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. RP Williams, CR (reprint author), NOAA, CIRES, Aeron Lab, Mail Stop R-E-AL3,325 Broadway, Boulder, CO 80303 USA. RI Williams, Christopher/A-2723-2015; Johnston, Paul/E-1914-2016 OI Williams, Christopher/0000-0001-9394-8850; Johnston, Paul/0000-0002-4046-9351 NR 19 TC 23 Z9 23 U1 1 U2 2 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 JUL PY 2000 VL 17 IS 7 BP 949 EP 962 DI 10.1175/1520-0426(2000)017<0949:CATTSA>2.0.CO;2 PG 14 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA 336RC UT WOS:000088315900006 ER PT J AU Shafer, MA Fiebrich, CA Arndt, DS Fredrickson, SE Hughes, TW AF Shafer, MA Fiebrich, CA Arndt, DS Fredrickson, SE Hughes, TW TI Quality assurance procedures in the Oklahoma Mesonetwork (vol 17, pg 474, 2000) SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Correction C1 Natl Severe Storms Lab, Norman, OK 73069 USA. Environm Verificat & Anal Ctr, Norman, OK USA. NR 1 TC 0 Z9 0 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 JUL PY 2000 VL 17 IS 7 BP 1001 EP 1001 PG 1 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA 336RC UT WOS:000088315900011 ER PT J AU Forney, D Kellogg, CB Thompson, WE Jacox, ME AF Forney, D Kellogg, CB Thompson, WE Jacox, ME TI The vibrational spectra of molecular ions isolated in solid neon. XVI. SO2+, SO2-, and (SO2)(2)(-) SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID SULFUR-DIOXIDE; CHARGE-TRANSFER; PHOTOELECTRON-SPECTROSCOPY; ELECTRON-AFFINITIES; MATRIX-ISOLATION; GAS-PHASE; ABINITIO CALCULATIONS; (SO2)(SO2-) DIMER; INFRARED-SPECTRUM; VALENCE SHELL AB When a Ne:SO2 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 with the aid of isotopic substitution studies to SO, SO2+, SO2-, (SO2)(2)(-), and, tentatively, SO-. The fundamental and first overtone absorptions of SO lie 0.9 and 1.8 cm(-1), respectively, below the gas-phase band centers. Ab initio calculations at the Hartree-Fock level show an instability in the v(3) vibration of SO2+ which is avoided by higher-level calculations. The nu(3) and nu(1) fundamentals of SO2- isolated in solid neon are identified at 1086.2 and 990.8 cm(-1), respectively. In agreement with an earlier proposal, the 1042 cm(-1) absorption originally assigned to nu(3) of SO2- trapped in solid argon is reassigned to MSO2, with M an alkali metal. Near the photodetachment threshold for SO2- isolated in a neon matrix, electron capture by SO2 nearest-neighbor pairs results in growth of infrared absorptions of (SO2)(2)(-), which has been shown by gas-phase studies to have a significantly higher photodetachment threshold than does SO2-. The isotopic substitution studies require that the two sulfur atoms in (SO2)(2)(-) be nonequivalent, favoring the linking of the two SO2 units by a S ... O bond. (C) 2000 American Institute of Physics. [S0021- 9606(00)00225-7]. C1 Technol Adm, Opt Technol Div, Natl Inst Stand & Technol, US Dept Commerce, Gaithersburg, MD 20899 USA. RP Forney, D (reprint author), Technol Adm, Opt Technol Div, Natl Inst Stand & Technol, US Dept Commerce, Gaithersburg, MD 20899 USA. NR 68 TC 33 Z9 33 U1 0 U2 8 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD JUL 1 PY 2000 VL 113 IS 1 BP 86 EP 97 AR PII [S0021-9606(00)00225-7] DI 10.1063/1.481777 PG 12 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 326TE UT WOS:000087750800012 ER PT J AU Mate, B Suenram, RD Lugez, C AF Mate, B Suenram, RD Lugez, C TI Microwave studies of three alkylbenzenes: Ethyl, n-propyl, and n-butylbenzene SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID SPECTRA; RELAXATION AB The rotational spectra of ethyl, n-propyl, and n-butylbenzene have been observed and analyzed using a high-resolution Fourier transform microwave spectrometer. Only one stable conformation was found for ethylbenzene, in agreement with previous results from Caminati [Mol. Phys. 74, 885 (1991)]. The high sensitivity of the technique allows observation of the rotational spectra of the six C-13 isotopes of ethylbenzene in natural abundance. The structural analysis indicates that the dihedral angle between the ethyl group and the ring plane is 88.7 degrees +/- 0.9 degrees. Two conformers have been found for n-propylbenzene as predicted by ab initio calculations while four of the five theoretically predicted conformers [Dickinson , J. Chem. Soc., Faraday Trans. 93, 1467 (1997)] have been found for n-butylbenzene. (C) 2000 American Institute of Physics. [S0021-9606(00)02025-0]. C1 Natl Inst Stand & Technol, Opt Technol Div, Gaithersburg, MD 20899 USA. RP Mate, B (reprint author), Natl Inst Stand & Technol, Opt Technol Div, Gaithersburg, MD 20899 USA. RI Mate, Belen/F-1135-2016 OI Mate, Belen/0000-0002-5478-8644 NR 13 TC 31 Z9 31 U1 0 U2 6 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD JUL 1 PY 2000 VL 113 IS 1 BP 192 EP 199 PG 8 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 326TE UT WOS:000087750800024 ER PT J AU Jabs, W McIntosh, AL Lucchese, RR Bevan, JW Brugh, DJ Suenram, RD AF Jabs, W McIntosh, AL Lucchese, RR Bevan, JW Brugh, DJ Suenram, RD TI Structure and dynamics of N-2-IH SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID TRANSFORM MICROWAVE SPECTROMETER; LEVEL-CORRELATED CALCULATIONS; MOLECULAR ELECTRIC PROPERTIES; POLARIZED BASIS-SETS; WEAKLY BOUND DIMERS; ROTATIONAL SPECTRUM; HYDROGEN HALIDES; CENTRIFUGAL-DISTORTION; CARBON-MONOXIDE; HCN-HF AB The ground state rotational spectra and internal dynamics in five isotopomers N-14(2)-IH, N-14(2)-ID, N-15(2)-IH, (NN)-N-14-N-15-IH, and (NN)-N-15-N-14-IH of the nitrogen-hydrogen iodine dimer have been investigated by pulsed-nozzle, Fourier-transform microwave spectroscopy. Analysis of the recorded spectra yields rotational, centrifugal distortion, nuclear quadrupole and spin-rotation coupling constants for the five isotopomers. The spectroscopic constants are interpreted in terms of a ground-state NN-IH structure using the parameters r(cm), k(sigma), and the oscillation angles theta(N2) and theta(HI) of the N-2 and IH moieties. For N-14(2)-IH, the values r(cm)=4.197 872(67) Angstrom, k(sigma)=1.461 52(32) N/m, theta(N2)=25.61(22)degrees, and theta(HI)=23.454 6(91)degrees are obtained. The rotational transitions of N-14(2)-IH, N-14(2)-ID, and N-15(2)-IH show a doubling, which is a consequence of tunneling associated with the interchange of the two nitrogen nuclei. The experimental findings are compared with results from ab initio calculations. (C) 2000 American Institute of Physics. [S0021-9606(00)02024-9]. C1 Texas A&M Univ, Dept Chem, College Stn, TX 77843 USA. Natl Inst Stand & Technol, Opt Technol Div, Gaithersburg, MD 20899 USA. RP Bevan, JW (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 36 TC 1 Z9 1 U1 0 U2 3 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD JUL 1 PY 2000 VL 113 IS 1 BP 249 EP 257 DI 10.1063/1.481791 PG 9 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 326TE UT WOS:000087750800030 ER PT J AU Akpalu, YA Amis, EJ AF Akpalu, YA Amis, EJ TI Effect of polydispersity on the evolution of density fluctuations to lamellar crystals in linear polyethylene SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID X-RAY-SCATTERING; SMALL-ANGLE; INDUCTION PERIOD; ISOTACTIC POLYPROPYLENE; STRUCTURAL FORMATION; ETHER KETONE); CRYSTALLIZATION; MELT; POLY(ETHYLENE-TEREPHTHALATE); FRACTIONS AB The effect of polydispersity on structure development in linear polyethylenes is studied by simultaneous real time small-angle x-ray scattering (SAXS) and wide-angle x-ray scattering (WAXS). Our measurements show that below 128 degrees C, changes in the SAXS and WAXS intensity profiles for a broad molecular-weight distribution sample occur simultaneously as previously reported for a narrow molecular-weight distribution sample. We demonstrate that variations in the SAXS profile can be correlated with the morphological changes associated with the evolution of single chain folded crystal lamellae to lamellar aggregates. At 128 degrees C and higher temperatures, changes in the SAXS intensity profile for the broad molecular weight distribution sample occur much earlier than the onset of lamellar crystal growth evidenced in the WAXS profile. For the period before crystal growth is manifest in the WAXS scattering, the SAXS intensity at low angles increases while the domain size remains constant. The low-angle intensity uptake in SAXS can be best described by the Guinier approximation. On the other hand, the temperature dependence of the variation in the average crystal thickness during isothermal crystal growth is a function of the relative rates of primary crystallization and thickening at a given temperature. We discuss the effect of a broad distribution in chain length on the various stages in the development of the morphology. [S0021-9606(00)51025-3]. C1 Natl Inst Stand & Technol, Div Polymers, Gaithersburg, MD 20899 USA. RP Akpalu, YA (reprint author), Natl Inst Stand & Technol, Div Polymers, Gaithersburg, MD 20899 USA. NR 39 TC 22 Z9 22 U1 1 U2 6 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD JUL 1 PY 2000 VL 113 IS 1 BP 392 EP 403 AR PII [S0021-9606(00)51025-3] DI 10.1063/1.481805 PG 12 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 326TE UT WOS:000087750800048 ER PT J AU Dudowicz, J Freed, KF Douglas, JF AF Dudowicz, J Freed, KF Douglas, JF TI Lattice model of living polymerization. III. Evidence for particle clustering from phase separation properties and "rounding" of the dynamical clustering transition SO JOURNAL OF CHEMICAL PHYSICS LA English DT Review ID DIRECTIONAL ATTRACTIVE FORCES; THERMODYNAMIC PERTURBATION-THEORY; SULFONATED POLYSTYRENE IONOMERS; ANGLE NEUTRON-SCATTERING; STRONGLY DIPOLAR FLUIDS; LIGHT-SCATTERING; THERMOREVERSIBLE GELATION; MOLECULAR-WEIGHT; LIQUID-PHASE; EQUILIBRIUM POLYMERIZATION AB Equilibrium polymerization is studied here as a prototype for clustering transitions that commonly occur in systems of interacting particles at equilibrium. These transitions are often difficult to locate because of transition "rounding" associated with a limited extent of cluster growth, competing association or dissociation processes that initiate or inhibit clustering, and other constraints on the particle clustering dynamics. Instead of singularities in thermodynamic and transport properties, more subtle property changes signal the onset of particle clustering, explaining why clustering transitions are often overlooked or misinterpreted. We utilize a Flory-Huggins model for the equilibrium ("living") polymerization of linear polymer chains to identify experimental signatures (features in the osmotic pressure, osmotic compressibility, and specific heat) that can be used to locate and quantify the transition "rounding" in general clustering transitions. The computation of a flattening in the concentration dependence of the osmotic pressure in the one-phase region motivates our consideration of the temperature dependence of the second virial coefficient and the variation of the theta temperature T-theta with "sticking energy" Delta h as possible important indicators of particle clustering. The ratio of the critical temperature T-c for phase separation to T-theta, along with other "critical constant" ratios, such as the osmotic compressibility factor Z(c), are also calculated and discussed in connection with establishing criteria for identifying particle clustering transitions and for quantifying the relative "strength" of these transitions. (C) 2000 American Institute of Physics. [S0021- 9606(00)50825-3]. C1 Univ Chicago, James Franck Inst, Chicago, IL 60637 USA. Univ Chicago, Dept Chem, Chicago, IL 60637 USA. Natl Inst Stand & Technol, Div Polymers, Gaithersburg, MD 20899 USA. RP Dudowicz, J (reprint author), Univ Chicago, James Franck Inst, 5640 S Ellis Ave, Chicago, IL 60637 USA. NR 126 TC 59 Z9 59 U1 0 U2 7 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD JUL 1 PY 2000 VL 113 IS 1 BP 434 EP 446 AR PII [S0021-9606(00)50825-3] DI 10.1063/1.481808 PG 13 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 326TE UT WOS:000087750800051 ER PT J AU Gordon, CT Rosati, A Gudgel, R AF Gordon, CT Rosati, A Gudgel, R TI Tropical sensitivity of a coupled model to specified ISCCP low clouds SO JOURNAL OF CLIMATE LA English DT Article ID EASTERN EQUATORIAL PACIFIC; SEA-SURFACE TEMPERATURE; GENERAL-CIRCULATION MODELS; OCEAN-ATMOSPHERE MODEL; SEASONAL CYCLE; INTERANNUAL VARIABILITY; GCM; FORECASTS; SCALE; ENSO AB The seasonal cycle of SST observed in the eastern equatorial Pacific is poorly simulated by many ocean-atmosphere coupled GCMs. This deficiency may be partly due to an incorrect prediction of tropical marine stratocumulus (MSc). To explore this hypothesis, two basic multiyear simulations have been performed using a coupled GCM with seasonally varying solar radiation. The model's cloud prediction scheme, which underpredicts tropical marine stratocumulus, is used for ail clouds in the control run. In contrast, in the "ISCCP" run, the climatological monthly mean low cloud fraction is specified over the open ocean, utilizing C2 data from the International Satellite Cloud Climatology Project (ISCCP). In this manner, the treatment of MSc clouds, including the annual cycle, is more realistic than in previous sensitivity studies. Robust surface and subsurface thermodynamical and dynamical responses to the specified MSc are found in the Tropics, especially near the equator. in the annual mean, the equatorial cold tongue extends farther west and intensifies, while the east-west SST gradient is enhanced. A double SST maximum Ranking the cold tongue becomes asymmetric about the equator. The SST annual cycle in the eastern equatorial Pacific strengthens, and the equatorial SST seasonal anomalies migrate farther westward. MSc-induced local shortwave radiative cooling enhances dynamical cooling associated with the southeast trades. The surface meridional wind stress in the extreme eastern equatorial Pacific remains southerly all year, while the surface zonal wind stress and equatorial upwelling intensify, as does the seasonal cycle of evaporation, in better agreement with observation. Within the ocean, the thermocline steepens and the Equatorial Undercurrent intensifies. When the low clouds are entirely removed, the SST warms by about 5.5 K in the western and central tropical Pacific, relative to "ISCCP," and the model's SST bias there reverses sign. ENSO-like interannual variability with a characteristic timescale of 3-5 yr is found in ail simulations, though its amplitude varies. The "ISCCP" equatorial cold tongue inhibits the eastward progression of ENSO-like warm events east of the dare line. When the specified low cloud fraction in "ISCCP'' is reduced by 20%, the interannual variability amplifies somewhat and the coupled model responds more like a delayed oscillator. The apparent sensitivity in the equatorial Pacific to a 20% relative change in low cloud fraction may have some cautionary implications for seasonal prediction by coupled GCMs. C1 Geophys Fluid Dynam Lab, Princeton, NJ USA. RP Gordon, CT (reprint author), Princeton Univ, NOAA, GFDL, Forrestal Campus,US Route 1,POB 308, Princeton, NJ 08542 USA. NR 41 TC 51 Z9 56 U1 1 U2 11 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8755 J9 J CLIMATE JI J. Clim. PD JUL 1 PY 2000 VL 13 IS 13 BP 2239 EP 2260 DI 10.1175/1520-0442(2000)013<2239:TSOACM>2.0.CO;2 PG 22 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 339QR UT WOS:000088489900007 ER PT J AU Zhang, CD McPhaden, MJ AF Zhang, CD McPhaden, MJ TI Intraseasonal surface cooling in the equatorial western Pacific SO JOURNAL OF CLIMATE LA English DT Article ID MADDEN-JULIAN OSCILLATION; AIR-SEA INTERACTION; TOGA COARE; WARM POOL; TROPICAL ATMOSPHERE; MIXED-LAYER; LONGWAVE RADIATION; SCALE CIRCULATION; OCEAN SURFACE; HEAT FLUXES AB Three idealized models for the surface structure of the Madden-Julian oscillation (MJO) were summarized from observations, numerical simulations, and theories, which demonstrate contrasting phase relationships of surface variables. To explore which model represents the most commonly observed features of the MJO in the western Pacific, in situ observations from moored buoys and satellite data were used to construct composite time series for components of surface fluxes of heat, momentum, and buoyancy during intraseasonal cooling episodes, defined as periods when the ocean loses heat through the surface. The composites show a near in-phase relationship among maxima in net surface cooling, latent heat Bur, precipitation rate, wind stress, westerly wind, and minima in solar radiation flux and net buoyancy flux. The phase of net buoyancy flux is determined by the net heat flux, whereas its magnitude is substantially compensated by freshwater flux. During the composite cooling episode, both the oceanic isothermal layer and mixed layer become deeper, the barrier layer becomes thinner, and the sea surface becomes cooler. The strength of atmospheric forcing and the oceanic response increases with the length of the cooling episodes. The phase relationships found in the composites are consistent with one of the three MJO models and with some previous studies based on observations and global model analyses but are inconsistent with others. Possible reasons for the disagreement among different studies and the implications of the disagreement are discussed. C1 Univ Miami, Rosenstiel Sch Marine & Atmospher Sci, Div Meteorol & Phys Oceanog, Miami, FL 33149 USA. NOAA, Pacific Marine Environm Lab, Seattle, WA 98115 USA. RP Zhang, CD (reprint author), Univ Miami, Rosenstiel Sch Marine & Atmospher Sci, Div Meteorol & Phys Oceanog, 4600 Rickenbacker Causeway, Miami, FL 33149 USA. RI McPhaden, Michael/D-9799-2016 NR 62 TC 69 Z9 73 U1 0 U2 7 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8755 J9 J CLIMATE JI J. Clim. PD JUL 1 PY 2000 VL 13 IS 13 BP 2261 EP 2276 DI 10.1175/1520-0442(2000)013<2261:ISCITE>2.0.CO;2 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 339QR UT WOS:000088489900008 ER PT J AU Guyer, JE Barnett, SA Voorhees, PW AF Guyer, JE Barnett, SA Voorhees, PW TI Morphological evolution of In0.26Ga0.74As grown under compression on GaAs(001) and under tension on InP(001) SO JOURNAL OF CRYSTAL GROWTH LA English DT Article DE heteroepitaxy; morphological stability ID MOLECULAR-BEAM EPITAXY; ALLOY THIN-FILMS; DIFFRACTION INTENSITY OSCILLATIONS; SURFACE-DIFFUSION LENGTH; ANGLE ION-BOMBARDMENT; III-V-SEMICONDUCTORS; FREE SOLID FILMS; CRITICAL THICKNESS; STABILITY; INSTABILITY AB The morphology and compositional uniformity of strained alloy films have recently been predicted to depend on the sign of the misfit strain between the film and the substrate. Other theories have been proposed where this is not the case. In order to test these contradictory predictions, we deposited In0.26Ga0.74As films on GaAs(001) and InP(001) substrates by molecular beam epitaxy. This alloy concentration was selected because its lattice parameter at the growth temperature (5.77 Angstrom) lies directly between those of GaAs (5.67 Angstrom) and InP (5.88 Angstrom). This enables growth under both 1.85% compressive and tensile misfit for the same film material. The surface energy, surface diffusivity, elastic parameters, and thermodynamic coefficients are nominally identical. This leaves the sign of the misfit and the film-substrate interface as the only variables, and the latter is expected to be a minor contributor. We find that the films grown under tension develop much smaller perturbations than do the films grown under compression. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Northwestern Univ, Dept Mat Sci & Engn, Evanston, IL 60208 USA. RP Guyer, JE (reprint author), Natl Inst Stand & Technol, Div Met, Gaithersburg, MD 20899 USA. EM guyer@nist.gov; s-barnett@northwestern.edu; p-voorhees@northwestern.edu RI Voorhees, Peter /B-6700-2009; Barnett, Scott/B-7502-2009; Guyer, Jonathan/M-5165-2016 OI Guyer, Jonathan/0000-0002-1407-6589 NR 58 TC 25 Z9 25 U1 0 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-0248 J9 J CRYST GROWTH JI J. Cryst. Growth PD JUL PY 2000 VL 217 IS 1-2 BP 1 EP 12 DI 10.1016/S0022-0248(00)00466-8 PG 12 WC Crystallography; Materials Science, Multidisciplinary; Physics, Applied SC Crystallography; Materials Science; Physics GA 337CT UT WOS:000088340400001 ER PT J AU Berrie, CL Leone, SR AF Berrie, CL Leone, SR TI Observation of monolayer and bilayer period RHEED oscillations during epitaxial growth of Ge on Ge(100) SO JOURNAL OF CRYSTAL GROWTH LA English DT Article DE molecular beam epitaxy; RHEED; elemental semiconductor processing; germanium ID ENERGY ELECTRON-DIFFRACTION; MOLECULAR-BEAM EPITAXY; SCANNING-TUNNELING-MICROSCOPY; INTENSITY OSCILLATIONS; MBE GROWTH; VICINAL SURFACES; SI(001); GE(111); RECONSTRUCTIONS; HETEROEPITAXY AB Both monolayer and bilayer periods are observed during the growth of germanium on Ge(1 0 0) using reflection high-energy electron diffraction (RHEED). Oscillations in the specular beam intensity of the RHEED pattern are recorded for substrate temperatures of 400-850 K over a wide range of incident germanium fluxes. With careful sample preparation, the period of the RHEED oscillations consistently goes through a transition from a bilayer period to an alternating intensity monolayer period as the surface temperature is raised above similar to 700 K. Without this preparation, only bilayer periods characterized by symmetric-shaped oscillations are observed. This indicates that the sample preparation plays a key role in determining the resulting growth. The period of the RHEED oscillations is not strongly dependent on the incident angle of the electron beam, suggesting that the observed periods are not a result of a diffraction condition, such as Kikuchi lines. The data are consistent with a mobility-controlled dynamic bilayer versus monolayer growth mechanism. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Colorado, JILA, Boulder, CO 80309 USA. Univ Colorado, Natl Inst Stand & Technol, Boulder, CO 80309 USA. Univ Colorado, Dept Chem & Biochem, Boulder, CO 80309 USA. RP Leone, SR (reprint author), Univ Colorado, JILA, Boulder, CO 80309 USA. NR 33 TC 5 Z9 5 U1 2 U2 8 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-0248 J9 J CRYST GROWTH JI J. Cryst. Growth PD JUL PY 2000 VL 216 IS 1-4 BP 159 EP 170 DI 10.1016/S0022-0248(00)00355-9 PG 12 WC Crystallography; Materials Science, Multidisciplinary; Physics, Applied SC Crystallography; Materials Science; Physics GA 336DE UT WOS:000088286000024 ER PT J AU Dabo, Y Thi, HN Coriell, SR McFadden, GB Li, Q Billia, B AF Dabo, Y Thi, HN Coriell, SR McFadden, GB Li, Q Billia, B TI Microsegregation in Peltier interface demarcation SO JOURNAL OF CRYSTAL GROWTH LA English DT Article DE alloy solidification; bismuth-antimony; Peltier effect; microsegregation ID CRYSTAL MELT INTERFACE; DIRECTIONAL SOLIDIFICATION; MORPHOLOGICAL STABILITY; ELECTRIC-FIELD; BINARY ALLOY; GROWTH; SIMULATION; BISMUTH AB Experimental results on solute microsegregation induced by Peltier interface demarcation (PID) technique during directional solidification of Bi-1 wt% Sb alloys are presented. These data are compared with the results of numerical simulation and the theory of PID is revisited. It is shown that the Peltier coefficient previously determined using Peltier pulsing has been underestimated. The quantity of interface cooling absorbed by limited Bi-growth kinetics is comparable to that covered by solute depiction, and can even be dominant for very short pulses, so that the commonly made assumption of Local equilibrium at the solid-liquid interface (i.e. usual hypothesis of constant interface temperature during pulse marking for pure systems) should be abandoned and the right dependence of interface temperature on solidification velocity be included in the model, Finally, two conditions to select systems capable of efficient marking by PID microsegregation are deduced and the effects of applied current in the first instants of electric pulse clarified. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Aixe Marseille III, L2MP, F-13397 Marseille 20, France. Fac Sci St Jerome, CNRS, F-13397 Marseille, France. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Thi, HN (reprint author), Univ Aixe Marseille III, L2MP, Case 151, F-13397 Marseille 20, France. RI McFadden, Geoffrey/A-7920-2008; Nguyen-Thi, Henri/D-5174-2012 OI McFadden, Geoffrey/0000-0001-6723-2103; NR 28 TC 13 Z9 13 U1 0 U2 9 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-0248 J9 J CRYST GROWTH JI J. Cryst. Growth PD JUL PY 2000 VL 216 IS 1-4 BP 483 EP 494 DI 10.1016/S0022-0248(00)00458-9 PG 12 WC Crystallography; Materials Science, Multidisciplinary; Physics, Applied SC Crystallography; Materials Science; Physics GA 336DE UT WOS:000088286000065 ER PT J AU Coriell, SR McFadden, GB Billia, B Thi, HN Dabo, Y AF Coriell, SR McFadden, GB Billia, B Thi, HN Dabo, Y TI Electrical pulsing during directional solidification: analysis of transients by Laplace transform SO JOURNAL OF CRYSTAL GROWTH LA English DT Article DE alloy solidification; bismuth-antimony; Peltier effect; microsegregation ID INTERFACE DEMARCATION AB The effect of the instantaneous application of an electric current during the directional solidification of a binary alloy is considered. The initial state consists of steady-state solidification at constant velocity. It is assumed that the electric current is sufficiently small that its application can be treated as a small perturbation. The problem is solved by Laplace transform techniques and the results are compared to numerical calculations for arbitrary currents. The Laplace transform allows for an understanding of the discontinuities resulting from the discontinuous electric pulse. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Aix Marseille III, L2MP, F-13397 Marseille 20, France. Fac Sci St Jerome, CNRS, F-13397 Marseille, France. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Billia, B (reprint author), Univ Aix Marseille III, L2MP, Case 151, F-13397 Marseille 20, France. RI McFadden, Geoffrey/A-7920-2008; Nguyen-Thi, Henri/D-5174-2012 OI McFadden, Geoffrey/0000-0001-6723-2103; NR 17 TC 11 Z9 11 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-0248 J9 J CRYST GROWTH JI J. Cryst. Growth PD JUL PY 2000 VL 216 IS 1-4 BP 495 EP 500 DI 10.1016/S0022-0248(00)00406-1 PG 6 WC Crystallography; Materials Science, Multidisciplinary; Physics, Applied SC Crystallography; Materials Science; Physics GA 336DE UT WOS:000088286000066 ER PT J AU Schwartz, RL Davico, GE Lineberger, WC AF Schwartz, RL Davico, GE Lineberger, WC TI Negative-ion photoelectron spectroscopy of CH3S- SO JOURNAL OF ELECTRON SPECTROSCOPY AND RELATED PHENOMENA LA English DT Article; Proceedings Paper CT Beijing International Conference on Photoelectron Spectroscopy: Molecules, Ions and CLusters (BICPES 99) CY SEP 12-17, 1999 CL BEIJING, PEOPLES R CHINA SP Chinese Acad Sci, Natl Nat Sci Fdn China DE anion photoelectron spectroscopy; thiomethoxyl; electron affinity; photodetachment ID LASER-INDUCED FLUORESCENCE; RADICAL CH3S; JAHN-TELLER; METHOXY; CF3S; PHOTODETACHMENT; DYNAMICS; SPECTRUM; ANIONS AB A 364-nm negative-ion photoelectron spectrum of CH3S- has been recorded. The electron affinity; is 1.867+/-0.004 eV. Well-resolved vibrational structure has been observed such that the C-S symmetric stretch and the C-H symmetric stretch have been measured at 725+/-15 cm(-1) and 1260+/-30 cm(-1), respectively. The spin-orbit splitting is reported at 265+/-15 cm(-1). The large spin-orbit splitting quenches the Jahn-Teller modes seen in the analogous radicals, CH3O and CF3S. (C) 2000 Elsevier Science B.V. All rights reserved. C1 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 Lineberger, WC (reprint author), Univ Colorado, Joint Inst Lab Astrophys, Campus Box 440, Boulder, CO 80309 USA. NR 21 TC 27 Z9 30 U1 0 U2 1 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 JUL PY 2000 VL 108 IS 1-3 BP 163 EP 168 DI 10.1016/S0368-2048(00)00125-0 PG 6 WC Spectroscopy SC Spectroscopy GA 343MA UT WOS:000088705100017 ER PT J AU Smith, DA AF Smith, DA TI The gravitational attraction of any polygonally shaped vertical prism with inclined top and bottom faces SO JOURNAL OF GEODESY LA English DT Article DE numerical integration; gravity; terrain corrections AB A closed formula for computing the gravitational attraction of a general vertical prism with N + 2 faces (N faces are vertical planes, the other two are the inclined top and bottom planes) in Cartesian coordinates is presented. In addition, the special case of a triangular prism is discussed. Algebraic differences and overlooked singularity conditions of a previously published formula of this computation (which was only for the triangular special case) were identified and are also presented. C1 NOAA, Natl Geodet Survey, Silver Spring, MD 20910 USA. RP Smith, DA (reprint author), NOAA, Natl Geodet Survey, N-NGS5,1315 E W Highway,SSMC3,Room 9316, Silver Spring, MD 20910 USA. NR 6 TC 14 Z9 14 U1 0 U2 2 PU SPRINGER-VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0949-7714 J9 J GEODESY JI J. Geodesy PD JUL PY 2000 VL 74 IS 5 BP 414 EP 420 DI 10.1007/s001900000102 PG 7 WC Geochemistry & Geophysics; Remote Sensing SC Geochemistry & Geophysics; Remote Sensing GA 341ZW UT WOS:000088621700004 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, 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 JUL 1 PY 2000 VL 105 IS A7 BP 16095 EP 16096 DI 10.1029/2000JA900065 PG 2 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 330KW UT WOS:000087962100031 ER PT J AU Levin, I Leapman, RD Kaiser, DL AF Levin, I Leapman, RD Kaiser, DL TI Microstructure and chemistry of nonstoichiometric (Ba,Sr)TiO3 thin films deposited by metalorganic chemical vapor deposition SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID DIELECTRIC-PROPERTIES; ELECTRICAL-PROPERTIES; BARIUM-TITANATE; (BA; ACCOMMODATION; MOCVD AB The microstructure and chemistry of (Ba,Sr)TiO3 thin films deposited on Pt/SiO2/Si substrates by metalorganic chemical Vapor deposition were studied using high-resolution transmission electron microscopy and quantitative spectrum imaging in electron energy loss spectroscopy. The grain boundaries in all films with overall Ti content ranging from 50.7% to 53.4% exhibit a significant increase in Ti/Ba ratio as compared to the grain interiors. The results suggest that the deviations of Ti/(Ba + Sr) ratio from the stoichiometric value of unity are accommodated by the creation of Ba/Sr vacancies, which segregate to the grain boundary regions. The films with Ti contents equal to or greater than 52% additionally contained an amorphous Ti-rich phase at some grain boundaries and multiple grain junctions; the amount of this phase increases with increasing overall Ti content. The analysis indicates that the amorphous phase can only partially account for the significant drop in dielectric permittivity accompanying increases in the Ti/(Ba + Sr) ratio. C1 NIST, Div Ceram, Gaithersburg, MD 20899 USA. NIH, Off Res Serv, Bioengn & Phys Sci Program, Bethesda, MD 20892 USA. RP Levin, I (reprint author), NIST, Div Ceram, Gaithersburg, MD 20899 USA. RI Levin, Igor/F-8588-2010 NR 20 TC 12 Z9 12 U1 0 U2 0 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 JUL PY 2000 VL 15 IS 7 BP 1433 EP 1436 DI 10.1557/JMR.2000.0207 PG 4 WC Materials Science, Multidisciplinary SC Materials Science GA 330NK UT WOS:000087968000002 ER PT J AU Wollman, DA Nam, SW Hilton, GC Irwin, KD Bergren, NF Rudman, DA Martinis, JM Newbury, DE AF Wollman, DA Nam, SW Hilton, GC Irwin, KD Bergren, NF Rudman, DA Martinis, JM Newbury, DE TI Microcalorimeter energy-dispersive spectrometry using a low voltage scanning electron microscope SO JOURNAL OF MICROSCOPY-OXFORD LA English DT Article DE EDS; energy dispersive spectrometer; low-beam-energy microanalysis; low-voltage microanalysis; microanalysis; microcalorimeter; microcalorimeter EDS; mu cal EDS ID MICROANALYSIS AB We describe the current performance of the prototype microcalorimeter energy-dispersive spectrometer (mu cal EDS) developed at NIST for X-ray microanalysis. We show that the low-energy mu cal EDS, designed for operation in the energy range 0.2-2 keV, offers significant advantages for low-beam-energy microanalysis. We present several examples in which the prototype mu cal EDS has been used to solve problems in low-voltage microanalysis, including the analysis of tungsten silicide (WSi2), titanium nitride (TiN) and barium titanate (BaTiO3) and the measurement of chemical shifts in Fe and C compounds. C1 Natl Inst Stand & Technol, Boulder, CO 80303 USA. NIST, Gaithersburg, MD 20899 USA. RP Wollman, DA (reprint author), Natl Inst Stand & Technol, 325 Broadway, Boulder, CO 80303 USA. NR 12 TC 18 Z9 19 U1 0 U2 5 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD OX2 0NE, OXON, ENGLAND SN 0022-2720 J9 J MICROSC-OXFORD JI J. Microsc.-Oxf. PD JUL PY 2000 VL 199 BP 37 EP 44 DI 10.1046/j.1365-2818.2000.00705.x PN 1 PG 8 WC Microscopy SC Microscopy GA 328NY UT WOS:000087858000002 ER PT J AU Lemmon, EW Jacobsen, RT AF Lemmon, EW Jacobsen, RT TI An international standard formulation for the thermodynamic properties of 1,1,1-trifluoroethane (HFC-143a) for temperatures from 161 to 450 K and pressures to 50 MPa SO JOURNAL OF PHYSICAL AND CHEMICAL REFERENCE DATA LA English DT Article DE caloric properties; density; equation of state; fundamental equation; HFC-143a; R-143a; thermodynamic properties; 1,1,1-trifluoroethane ID SATURATED-LIQUID DENSITIES; 2ND VIRIAL-COEFFICIENTS; VAPOR-PRESSURES; 1,1-DIFLUOROETHANE R152A; PVT PROPERTIES; GAS-PHASE; HALOGENATED HYDROCARBONS; CRITICAL PARAMETERS; HEAT-CAPACITIES; 35 MPA AB A new formulation is presented for the thermodynamic. properties of refrigerant 143a (1,1,1-trifluoroethane, CH3-CF3) based upon available experimental data. The formulation can be used for the calculation of density, heat capacity, speed of sound, energy, and saturation properties using an equation of state explicit in Helmholtz energy. Ancillary equations are given for the ideal gas heat capacity, the vapor pressure, and for the saturated liquid and vapor densities as functions of temperature. Comparisons to available experimental data are given that establish the accuracy of calculated properties using this equation of state. The estimated uncertainties of properties calculated using the new equation are 0.1% in density, 0.5% in heat capacities, 0.02% in the speed of sound for the vapor at pressures less than 1 MPa, 0.5% in the speed of sound elsewhere, and 0.1% in vapor pressure, except in the critical region. The equation is valid for temperatures from the triple point temperature (161.34 K) to 450 K and pressures up to 50 MPa, and can be extrapolated to 650 K. It has been accepted as an international standard formulation for the properties of R-143a by the International Energy Agency-Annex 18. (C) 2001 by the U.S Secretary of Commerce on behalf of the United States. All rights reserved. C1 NIST, Phys & Chem Properties Div, Boulder, CO 80305 USA. Univ Idaho, Coll Engn, Ctr Appl Thermodynam Studies, Moscow, ID 83844 USA. RP Lemmon, EW (reprint author), NIST, Phys & Chem Properties Div, 325 Broadway, Boulder, CO 80305 USA. NR 61 TC 49 Z9 52 U1 1 U2 7 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0047-2689 J9 J PHYS CHEM REF DATA JI J. Phys. Chem. Ref. Data PD JUL-AUG PY 2000 VL 29 IS 4 BP 521 EP 552 DI 10.1063/1.1318909 PG 32 WC Chemistry, Multidisciplinary; Chemistry, Physical; Physics, Multidisciplinary SC Chemistry; Physics GA 411DR UT WOS:000167483300001 ER PT J AU Christophorou, LG Olthoff, JK AF Christophorou, LG Olthoff, JK TI Electron interactions with CF3I SO JOURNAL OF PHYSICAL AND CHEMICAL REFERENCE DATA LA English DT Article DE attachment; CF3I; coefficients; cross sections; electron interactions; electron transport; ionization; scattering; trifluoroiodomethane ID CROSS-SECTIONS; TEMPERATURE-DEPENDENCE; ENERGY-DISTRIBUTION; CONDENSED CF3I; RATE CONSTANTS; GAS-PHASE; HIGH-N; ATTACHMENT; COLLISIONS; CHEMISTRIES AB Low-energy electron collision data for the plasma processing gas CF3I are sparse. Limited cross section data are available only for total and differential elastic electron scattering, electron-impact ionization, and electron attachment. These data are assessed, synthesized, and discussed in this paper. There is a need for confirming measurements for some of these data, and for measurements of cross sections for the other main electron-collision processes for which no data exist. There are presently no data available for the electron transport, ionization, and attachment coefficients of this molecule. (C) 2001 by the U.S. Secretary of Commerce on behalf of the United States. All rights reserved. C1 NIST, Div Elect, Elect & Elect Engn Lab, Gaithersburg, MD 20899 USA. RP Christophorou, LG (reprint author), NIST, Div Elect, Elect & Elect Engn Lab, Gaithersburg, MD 20899 USA. NR 83 TC 67 Z9 70 U1 1 U2 9 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0047-2689 J9 J PHYS CHEM REF DATA JI J. Phys. Chem. Ref. Data PD JUL-AUG PY 2000 VL 29 IS 4 BP 553 EP 569 DI 10.1063/1.1318910 PG 17 WC Chemistry, Multidisciplinary; Chemistry, Physical; Physics, Multidisciplinary SC Chemistry; Physics GA 411DR UT WOS:000167483300002 ER PT J AU Fedorov, AV Melville, WK AF Fedorov, AV Melville, WK TI Kelvin fronts on the equatorial thermocline SO JOURNAL OF PHYSICAL OCEANOGRAPHY LA English DT Article ID PACIFIC-OCEAN; GEOSTROPHIC ADJUSTMENT; WAVES; CHANNEL; FLOW AB Properties of internal wave fronts or Kelvin fronts travelling eastward in the equatorial waveguide are studied, motivated by recent studies on coastal Kelvin waves and jumps and new data on equatorial Kelvin waves. It has been recognized for some time that nonlinear equatorial Kelvin waves can steepen and break, forming a broken wave of depression, or front, propagating eastward. The three-dimensional structure of the wave field associated with such a front is considered. As for linear Kelvin waves, the front is symmetrical with respect to the equator. Sufficiently far away from the front, the wave profile is Gaussian in the meridional direction, with the equatorial Rossby radius of deformation being its decay scale. Due to nonlinearity, the phase speed of the front is greater than that of linear Kelvin waves, resulting in a supercritical Row. This leads to the resonant generation of equatorially trapped gravity-inertial (or Poincare) waves, analogous in principle to the resonant mechanism for nonlinear coastal Kelvin waves. First-mode symmetrical Poincare waves are generated, with their wavelength determined by the amplitude of the front. Finally. the propagation of a Kelvin front gives rise to a nonzero poleward mass transport above the thermocline, in consequence of which there is a poleward heat flux. C1 Princeton Univ, Program Atmospher & Ocean Sci, Princeton, NJ 08544 USA. Univ Calif San Diego, Scripps Inst Oceanog, La Jolla, CA 92093 USA. RP Fedorov, AV (reprint author), Princeton Univ, Program Atmospher & Ocean Sci, POB CN710,Sayre Hall, Princeton, NJ 08544 USA. RI fedorov, alexey/F-1879-2010 NR 27 TC 27 Z9 28 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 JUL PY 2000 VL 30 IS 7 BP 1692 EP 1705 DI 10.1175/1520-0485(2000)030<1692:KFOTET>2.0.CO;2 PG 14 WC Oceanography SC Oceanography GA 341GY UT WOS:000088583700011 ER PT J AU Vossepoel, FC Behringer, DW AF Vossepoel, FC Behringer, DW TI Impact of sea level assimilation on salinity variability in the western equatorial Pacific SO JOURNAL OF PHYSICAL OCEANOGRAPHY LA English DT Article ID ATMOSPHERE RESPONSE EXPERIMENT; IMPROVED COUPLED MODEL; TROPICAL PACIFIC; OCEAN INITIALIZATION; ENSO PREDICTION; WIND STRESS; TOGA DECADE; FRESH POOL; PART II; ALTIMETER AB In the primitive equation model for the tropical Pacific at the National Centers for Environmental Prediction, subsurface temperature observations are assimilated. The addition of TOPEX/Poseidon sea level observations to the NCEP assimilation scheme has resulted in large differences in sea level during 1996. These differences are suggested to be related to salinity variability. A bivariate assimilation scheme is presented that corrects both temperature and salinity. The method is tested with synthetic data in an identical triplets experiment, in which a westerly wind burst is simulated. In this experiment, the correction of salinity improves the density simulation and attenuates errors in salinity. A four-year assimilation experiment with real data is performed to test the system's performance for 1993-96. In this experiment. the assimilation of TOPEX/Poseidon observations improves dynamic height simulation without degrading the temperature held. This application of altimetry improves the mean salinity in the western equatorial Pacific and leads to a more pronounced salinity variability in the ocean model. C1 Royal Netherlands Meteorol Inst, NL-3730 AE De Bilt, Netherlands. Delft Inst Earth Oriented Space Res, Delft, Netherlands. NOAA, Natl Ctr Environm Predict, Washington, DC USA. RP Vossepoel, FC (reprint author), Univ Paris 06, Lab Oceanog Dynam & Climatol, Tour 26,4eme Etage,4 Pl Jussieu, F-75252 Paris 05, France. NR 53 TC 34 Z9 39 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 JUL PY 2000 VL 30 IS 7 BP 1706 EP 1721 DI 10.1175/1520-0485(2000)030<1706:IOSLAO>2.0.CO;2 PG 16 WC Oceanography SC Oceanography GA 341GY UT WOS:000088583700012 ER PT J AU Yi, XH Portnoy, J Pellegrino, J AF Yi, XH Portnoy, J Pellegrino, J TI Diffusion measurements using ATR-FTIR spectroscopy: Acetone diffusion in polypropylene - Use of penetrant fluid pressure to improve sample/IRE contact SO JOURNAL OF POLYMER SCIENCE PART B-POLYMER PHYSICS LA English DT Article DE acetone; diffusion; ATR-FTIR spectroscopy; polypropylene ID INFRARED-SPECTROSCOPY; POLYMERS AB In this article, we present a simple method for improving the contact between a film sample and the internal reflection element (or crystal) when diffusion into thin polymer films is measured with attenuated total reflectance (ATR)-Fourier transform infrared spectroscopy. Intimate film/crystal contact is particularly important for making measurements on premade films and materials that cannot be solution-coated onto the crystal. This method is based on controlling the penetrant fluid pressure above a threshold value (>230 kPa) in the ATR flow cell. Measurements of acetone diffusion into a commercial polypropylene film at 300 K and varied pressures indicated that the diffusion time constant was constant at pressures above this threshold. We also monitored the absorbance of a polymer band that had no overlap with the acetone spectrum to examine whether adequate sample-film/crystal contact was reached and maintained. From these observations, we concluded that an apparently good match between the experimental data and a model calculation does not alone justify confidence in the accuracy of the calculated diffusion time constant. Additionally, the practice of using a reference band to correct the uncertainty in absorbance for bands of interest (due to imperfect sample/crystal contact) yielded inconsistent results. We also report further measurements of acetone diffusivity in a polypropylene film at temperatures ranging from 278 to 308 K that yielded an estimated activation energy for diffusion of 98 kJ/mol. (C) 2000 John Wiley & Sons, Inc. C1 Natl Inst Stand & Technol, Div 838, Boulder, CO 80303 USA. RP Pellegrino, J (reprint author), Natl Inst Stand & Technol, Div 838, Boulder, CO 80303 USA. OI PELLEGRINO, JOHN/0000-0001-7749-5003 NR 16 TC 11 Z9 11 U1 0 U2 4 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 JUL 1 PY 2000 VL 38 IS 13 BP 1773 EP 1787 DI 10.1002/1099-0488(20000701)38:13<1773::AID-POLB110>3.0.CO;2-9 PG 15 WC Polymer Science SC Polymer Science GA 322MM UT WOS:000087513400011 ER PT J AU Widmann, JF Charagundla, SR Presser, C AF Widmann, JF Charagundla, SR Presser, C TI Reference spray combustion facility for computational fluid dynamics model validation SO JOURNAL OF PROPULSION AND POWER LA English DT Article; Proceedings Paper CT 2nd International Conference on Advanced Energy Conversion Systems and Related Technologies (RAN98) CY DEC 01-03, 1998 CL NAGOYA UNIV, NAGOYA, JAPAN HO NAGOYA UNIV C1 Natl Inst Stand & Technol, Fire Safety Engn Div, Gaithersburg, MD 20899 USA. Natl Inst Stand & Technol, Proc Measurements Div, Gaithersburg, MD 20899 USA. RP Widmann, JF (reprint author), Natl Inst Stand & Technol, Fire Safety Engn Div, Stop 8640,100 Bur Dr, Gaithersburg, MD 20899 USA. NR 8 TC 1 Z9 1 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0748-4658 J9 J PROPUL POWER JI J. Propul. Power PD JUL-AUG PY 2000 VL 16 IS 4 BP 720 EP 723 DI 10.2514/2.5634 PG 4 WC Engineering, Aerospace SC Engineering GA 336NJ UT WOS:000088308900031 ER PT J AU Paul, RL AF Paul, RL TI Measurement of phosphorus in metals by RNAA SO JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY LA English DT Article; Proceedings Paper CT 10th International Conference on Modern Trends in Activation Analysis (MTAA-10) CY APR 19-23, 1999 CL NIH, BETHESDA, MARYLAND SP Natl Inst Stand & Technol HO NIH AB An RNAA procedure has been developed for measurement of low-level phosphorus in metals. Samples are irradiated at a neutron flux of 2.7.10(13) n.cm(-2).s(-1) then mixed with carrier and dissolved in acid. After chemical separation and purification of the phosphorus and gravimetric determination of carrier yield, P-32 is determined using a beta proportional counter. The detection limit for a 0.1 g sample irradiated for 30 minutes is 5 mu g/kg. The method has been used to determine 6.4+/-0.6 mg/kg phosphorus in SRM 2175 refractory alloy. C1 NIST, Div Analyt Chem, Gaithersburg, MD 20899 USA. RP Paul, RL (reprint author), NIST, Div Analyt Chem, Gaithersburg, MD 20899 USA. NR 3 TC 6 Z9 6 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0236-5731 J9 J RADIOANAL NUCL CH JI J. Radioanal. Nucl. Chem. PD JUL PY 2000 VL 245 IS 1 BP 11 EP 15 DI 10.1023/A:1006705803857 PG 5 WC Chemistry, Analytical; Chemistry, Inorganic & Nuclear; Nuclear Science & Technology SC Chemistry; Nuclear Science & Technology GA 338GN UT WOS:000088410900002 ER PT J AU Greenberg, RR Lindstrom, RM Simons, DS AF Greenberg, RR Lindstrom, RM Simons, DS TI Instrumental neutron activation analysis for certification of ion-implanted arsenic in silicon SO JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY LA English DT Article; Proceedings Paper CT 10th International Conference on Modern Trends in Activation Analysis (MTAA-10) CY APR 19-23, 1999 CL NIH, BETHESDA, MARYLAND SP Natl Inst Stand & Technol HO NIH ID HALF-LIVES AB Standard reference material (SRM) 2134 Arsenic Implant in Silicon was produced at the National Institute of Standards and Technology (NIST) as a calibrant for secondary ion mass spectrometry. Instrumental neutron activation analysis was used as a primary method for certification of the arsenic implanted dose. A complete evaluation of all sources of uncertainty yielded an expanded relative uncertainty for the mean value of this SRM to be 0.38% at approximately the 95% level of confidence. No evidence indicating significant heterogeneity among samples was observed. C1 Natl Inst Stand & Technol, Chem Sci & Technol Lab, Gaithersburg, MD 20899 USA. RP Greenberg, RR (reprint author), Natl Inst Stand & Technol, Chem Sci & Technol Lab, Gaithersburg, MD 20899 USA. NR 11 TC 30 Z9 30 U1 0 U2 3 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0236-5731 J9 J RADIOANAL NUCL CH JI J. Radioanal. Nucl. Chem. PD JUL PY 2000 VL 245 IS 1 BP 57 EP 63 DI 10.1023/A:1006703131599 PG 7 WC Chemistry, Analytical; Chemistry, Inorganic & Nuclear; Nuclear Science & Technology SC Chemistry; Nuclear Science & Technology GA 338GN UT WOS:000088410900010 ER PT J AU Zeisler, R AF Zeisler, R TI Investigations by INAA for the development of Natural Matrix Standard Reference Materials (R) (SRMs) suitable for small sample analysis SO JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY LA English DT Article; Proceedings Paper CT 10th International Conference on Modern Trends in Activation Analysis (MTAA-10) CY APR 19-23, 1999 CL NIH, BETHESDA, MARYLAND SP Natl Inst Stand & Technol HO NIH AB Instrumental neutron activation analysis (INAA) procedures were optimized for the analysis of small (1 mg) solid samples. This process included sample handling as well as detailed evaluation of high rate counting techniques, also in conjunction with rapidly decaying sources, to establish the necessary analysis environment for the determination of large numbers of samples with high reproducibility. The investigated materials included biological materials such as peach leaves (SRM 1547), lichen, and bovine liver, as well as environmental materials such as urban particulate matter (SRM 1648), and deep ocean sediment. The analytical data obtained with the INAA procedures were used to determine homogeneity values. C1 Natl Inst Stand & Technol, Div Analyt Chem, Gaithersburg, MD 20899 USA. RP Zeisler, R (reprint author), Natl Inst Stand & Technol, Div Analyt Chem, Gaithersburg, MD 20899 USA. NR 11 TC 7 Z9 7 U1 1 U2 2 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0236-5731 J9 J RADIOANAL NUCL CH JI J. Radioanal. Nucl. Chem. PD JUL PY 2000 VL 245 IS 1 BP 81 EP 85 DI 10.1023/A:1006719601557 PG 5 WC Chemistry, Analytical; Chemistry, Inorganic & Nuclear; Nuclear Science & Technology SC Chemistry; Nuclear Science & Technology GA 338GN UT WOS:000088410900013 ER PT J AU Norman, BR Becker, DA AF Norman, BR Becker, DA TI Determination of ultratrace levels of mercury in three SRMs by combustion RNAA SO JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY LA English DT Article; Proceedings Paper CT 10th International Conference on Modern Trends in Activation Analysis (MTAA-10) CY APR 19-23, 1999 CL NIH, BETHESDA, MARYLAND SP Natl Inst Stand & Technol HO NIH AB A radiochemical neutron activation analysis (RNAA) combustion method coupled with a neutron exposure normalization technique was used to determine low mu g/kg mercury levels in three National Institute of Standards and Technology (NIST) Standard Reference Materials (SRMs). Two coals (sub-bituminous and bituminous) and a diet material were analyzed. The results obtained provided recommended values of approximately 5 mu g/kg for SRM 1548a Typical Diet, 24 mu g/kg for SRM 1635 Trace Elements in Coal (sub-bituminous), and 100 mu g/kg for SRM 1632b Trace Elements in Coal (bituminous). C1 Natl Inst Stand & Technol, Div Analyt Chem, Spectrochem Methods Grp, Gaithersburg, MD 20899 USA. Natl Inst Stand & Technol, Div Analyt Chem, Nucl Methods Grp, Gaithersburg, MD 20899 USA. RP Norman, BR (reprint author), Natl Inst Stand & Technol, Div Analyt Chem, Spectrochem Methods Grp, Gaithersburg, MD 20899 USA. NR 3 TC 5 Z9 5 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0236-5731 J9 J RADIOANAL NUCL CH JI J. Radioanal. Nucl. Chem. PD JUL PY 2000 VL 245 IS 1 BP 91 EP 95 DI 10.1023/A:1006775702465 PG 5 WC Chemistry, Analytical; Chemistry, Inorganic & Nuclear; Nuclear Science & Technology SC Chemistry; Nuclear Science & Technology GA 338GN UT WOS:000088410900015 ER PT J AU Bode, P Fernandes, EAD Greenberg, RR AF Bode, P Fernandes, EAD Greenberg, RR TI Metrology for chemical measurements and the position of INAA SO JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY LA English DT Article; Proceedings Paper CT 10th International Conference on Modern Trends in Activation Analysis (MTAA-10) CY APR 19-23, 1999 CL NIH, BETHESDA, MARYLAND SP Natl Inst Stand & Technol HO NIH ID NEUTRON-ACTIVATION ANALYSIS; DEAD-TIME AB Metrology systems are being established by various countries for the worldwide comparability of data related to trade, industrial products, health, and the environment. This has in turn led to an increased interest in methods that have the highest possible accuracy and precision. The relevance of instrumental neutron activation analysis (INAA) for metrological science has been evaluated. It is concluded that INAA is a suitable technique for method validation, proficiency testing development of reference materials and reference methods. Moreover, it is concluded that INAA may comply with the CCQM definition of a definitive or primary ratio method provided that the uncertainty in the results is reduced to much lower levels compared to those currently encountered in most NAA laboratories. C1 Delft Univ Technol, Interfac Reactor Inst, NL-2629 JB Delft, Netherlands. Univ Sao Paulo, Ctr Energia Nucl Agr, BR-13400970 Piracicaba, SP, Brazil. Natl Inst Stand & Technol, Div Analyt Chem, Gaithersburg, MD 20899 USA. RP Bode, P (reprint author), Delft Univ Technol, Interfac Reactor Inst, Mekelweg 15, NL-2629 JB Delft, Netherlands. RI De Nadai Fernandes, Elisabete/F-9018-2015 OI De Nadai Fernandes, Elisabete/0000-0003-1218-4882 NR 21 TC 32 Z9 32 U1 0 U2 6 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0236-5731 J9 J RADIOANAL NUCL CH JI J. Radioanal. Nucl. Chem. PD JUL PY 2000 VL 245 IS 1 BP 109 EP 114 DI 10.1023/A:1006752509734 PG 6 WC Chemistry, Analytical; Chemistry, Inorganic & Nuclear; Nuclear Science & Technology SC Chemistry; Nuclear Science & Technology GA 338GN UT WOS:000088410900018 ER PT J AU Kawamura, H Parr, RM Dang, HS Tian, W Barnes, RM Iyengar, GV AF Kawamura, H Parr, RM Dang, HS Tian, W Barnes, RM Iyengar, GV TI Analytical quality assurance procedures developed for the IAEA's Reference Asian Man Project (Phase 2) SO JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY LA English DT Article; Proceedings Paper CT 10th International Conference on Modern Trends in Activation Analysis (MTAA-10) CY APR 19-23, 1999 CL NIH, BETHESDA, MD SP Natl Inst Stand & Technol HO NIH AB Analytical quality assurance procedures adopted for use in the IAEA Go-ordinated Research Project on Ingestion and Organ Content of Trace Elements of Importance in Radiological Protection are designed to ensure comparability of the analytical results for Cs, I, Sr, Th, U and other elements in human tissues and diets collected and analysed in nine participating countries. The main analytical techniques are NAA and ICP-MS. For sample preparation, all participants are using identical food blenders which have been centrally supplied after testing for contamination. For quality control of the analyses, six NIST SRMs covering a range of matrices with certified and reference values for the elements of interest have been distributed. A new Japanese reference diet material has also been developed. These quality assurance procedures are summarized here and new data are presented for Cs, I, Sr, Th and U in the NIST SRMs. C1 Natl Inst Radiol Sci, Hitachinaka, Ibaraki 3111202, Japan. IAEA, A-1400 Vienna, Austria. Bhabha Atom Res Ctr, Bombay 400085, Maharashtra, India. China Inst Atom Energy, Beijing 102413, Peoples R China. Univ Massachusetts, Amherst, MA 01003 USA. NIST, Gaithersburg, MD 20899 USA. RP Kawamura, H (reprint author), Natl Inst Radiol Sci, Hitachinaka, Ibaraki 3111202, Japan. EM h_kawamu@nirs.go.jp; r.parr@xpoint.at; hsdang@magnum.barct1.ernet.in; tiancia@public.bta.net.cn; ramon.m.barnes@chemistry.umass.edu; V.Iyengar@iaea.org NR 4 TC 19 Z9 19 U1 0 U2 1 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0236-5731 J9 J RADIOANAL NUCL CH JI J. Radioanal. Nucl. Chem. PD JUL PY 2000 VL 245 IS 1 BP 123 EP 126 DI 10.1023/A:1006712813369 PG 4 WC Chemistry, Analytical; Chemistry, Inorganic & Nuclear; Nuclear Science & Technology SC Chemistry; Nuclear Science & Technology GA 338GN UT WOS:000088410900020 ER PT J AU Currie, LA AF Currie, LA TI Detection and quantification capabilities and the evaluation of low-level data: Some international perspectives and continuing challenges SO JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY LA English DT Article; Proceedings Paper CT 10th International Conference on Modern Trends in Activation Analysis (MTAA-10) CY APR 19-23, 1999 CL NIH, BETHESDA, MARYLAND SP Natl Inst Stand & Technol HO NIH ID C-14 AB The minimum amounts or concentrations of an analyte that may be detected or quantified by a specific measurement process (MP) represent fundamental performance characteristics that are vital for planning experiments and designing MPs to meet external specifications. Following many years of conceptual and terminological disarray regarding detection and quantification limits, the International Union of Pure and Applied Chemistry(IUPAC, 1995)(1) and the International Organization for Standardization (ISO, 1997)(2) developed a harmonized position and documents that provide a basis for international consensus on this topic. During the past year, the International Atomic Energy Agency (IAEA) has developed a TECDOC on Quantifying Uncertainty in Nuclear Analytical Measurements that treats "Uncertainty in Measurements Close to Detection Limits" from the perspective of the IUPAC and ISO recommendations.(3) The first part of this article serves as a review of these international developments during the last quinquennium of the twentieth century. Despite the achievement of international consensus on these contentious matters, many challenges remain. One quickly discovers this in the practical world of high stakes, ultra-trace analysis, where complications are introduced by the nature and distribution of the blank, the variance function (sigma vs. concentration), non-linear models, and hidden algorithms and data evaluation/reporting schemes. Some of these issues are illustrated through a multidisciplinary case study of fossil and biomass burning aerosol at extremely low levels in the polar atmosphere and cryosphere, and by biased reporting practices for "non-detects." C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Currie, LA (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NR 42 TC 12 Z9 12 U1 0 U2 7 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0236-5731 J9 J RADIOANAL NUCL CH JI J. Radioanal. Nucl. Chem. PD JUL PY 2000 VL 245 IS 1 BP 145 EP 156 DI 10.1023/A:1006733415186 PG 12 WC Chemistry, Analytical; Chemistry, Inorganic & Nuclear; Nuclear Science & Technology SC Chemistry; Nuclear Science & Technology GA 338GN UT WOS:000088410900024 ER PT J AU Pomme, S Simonits, A Lindstrom, R De Corte, F Robouch, P AF Pomme, S Simonits, A Lindstrom, R De Corte, F Robouch, P TI Determination of burnup effects in Au-197(n,gamma)Au-198 prior to reactor neutron field characterisation SO JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY LA English DT Article; Proceedings Paper CT 10th International Conference on Modern Trends in Activation Analysis (MTAA-10) CY APR 19-23, 1999 CL NIH, BETHESDA, MARYLAND SP Natl Inst Stand & Technol HO NIH ID ACTIVATION ANALYSIS; ALPHA-DETERMINATION; NUCLEAR-DATA; SPECTRUM; ACCURACY; K(0); NAA AB A simple and accurate method is presented to evaluate the burnup effects involved in the neutron activation of Au-197 prior to any neutron flux characterisation, based on the spectrometry of the Au-198 and Au-199 decay gammas. The obtained burnup factor can be used as input for reactor neutron field characterisation techniques using Au-197(n,gamma)Au-198 as a monitor. This way an iterative procedure is avoided. C1 CEN SCK, Belgian Nucl Res Ctr, B-2400 Mol, Belgium. Hungarian Acad Sci, KFKI Atom Energy Res Inst, H-1525 Budapest, Hungary. Natl Inst Stand & Technol, Div Analyt Chem, Gaithersburg, MD 20899 USA. State Univ Ghent, Analyt Chem Lab, Inst Nucl Sci, B-9000 Ghent, Belgium. European Commiss, Joint Res Ctr, Inst Reference Mat & Measurements, B-2440 Geel, Belgium. RP Pomme, S (reprint author), CEN SCK, Belgian Nucl Res Ctr, Boeretan 200, B-2400 Mol, Belgium. OI Pomme, Stefaan/0000-0001-5017-7451 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 0236-5731 J9 J RADIOANAL NUCL CH JI J. Radioanal. Nucl. Chem. PD JUL PY 2000 VL 245 IS 1 BP 223 EP 227 DI 10.1023/A:1006776003316 PG 5 WC Chemistry, Analytical; Chemistry, Inorganic & Nuclear; Nuclear Science & Technology SC Chemistry; Nuclear Science & Technology GA 338GN UT WOS:000088410900037 ER PT J AU Snyder, KA Ferraris, C Martys, NS Garboczi, EJ AF Snyder, KA Ferraris, C Martys, NS Garboczi, EJ TI Using impedance spectroscopy to assess the viability of the rapid chloride test for determining concrete conductivity SO JOURNAL OF RESEARCH OF THE NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY LA English DT Article DE building technology; concrete; inductivity; diffusivity; impedance spectroscopy; rapid chloride test ID CEMENT-BASED MATERIALS; ELECTRICAL-RESISTIVITY; PERMEABILITY TEST; PASTES; DIFFUSIVITY AB The suitability of using the initial current from the rapid chloride test (ASTM C 1202) to determine specimen conductivity is tested using impedance spectroscopy with a frequency spectrum of 10 Hz to 1 MHz. The specimen conductivity has an analytical relationship to specimen diffusivity and so is a useful quantity in service life prediction. Measurements made on specimens of different lengths indicate that the total charge passed during the six hour conduction test carried out according to ASTM C 1202 is not a direct measure of specimen conductivity. Further, ohmic heating during the 6 hour test makes it nearly impossible to directly measure any specimen transport property from the results. The total charge passed during the 6 hour conduction test is, therefore, not a reliable quantity for service life prediction. Results indicate that the direct current (dc) measurement of resistance using a voltage of 60 V is sufficient to overwhelm polarization effects, thereby yielding an accurate estimate of the true specimen conductivity. Impedance spectroscopy measurements also indicate that corrosion may form on the brass electrodes, adding bias to a conductivity estimate based upon a dc measurement. C1 Natl Inst Stand & Technol, Inorgan Bldg Mat Grp, Gaithersburg, MD 20899 USA. Natl Inst Stand & Technol, Fire Res Lab, Gaithersburg, MD 20899 USA. RP Snyder, KA (reprint author), Natl Inst Stand & Technol, Inorgan Bldg Mat Grp, NIST Bldg, Gaithersburg, MD 20899 USA. EM kenneth.snyder@nist.gov; chiara.ferraris@nist.gov; nicos.martys@nist.gov; edward.garboczi@nist.gov NR 44 TC 35 Z9 37 U1 0 U2 6 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 JUL-AUG PY 2000 VL 105 IS 4 BP 497 EP 509 DI 10.6028/jres.105.040 PG 13 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 357EG UT WOS:000089485100001 PM 27551618 ER PT J AU Liggett, WS Low, SR Pitchure, DJ Song, J AF Liggett, WS Low, SR Pitchure, DJ Song, J TI Capability in Rockwell C scale hardness SO JOURNAL OF RESEARCH OF THE NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY LA English DT Article DE calibration; critical to product quality; experimental design; indentation hardness; measurement system comparison; spatial statistics; standard reference material; surface measurement; test method; trend elimination; uncertainty component AB A measurement system is capable if it produces measurements with uncertainties small enough for demonstration of compliance with product specifications. To establish the capability of a system for Rockwell C scale hardness, one must assess measurement uncertainty and, when hardness is only an indicator, quantify the relation between hardness and the product property of real interest. The uncertainty involves several components, which we designate as lack of repeatability, lack of reproducibility, machine error, and indenter error. Component-by-component assessment leads to understanding of mechanisms and thus to guidance on system upgrades if these are necessary. Assessment of some components calls only for good-quality test blocks, and assessment of others requires test blocks that NIST issues as Standard Reference Materials (SRMs). The important innovation introduced in this paper is improved handling of the hardness variation across test-block surfaces. In addition to hardness itself, the methods in this paper might be applicable to other local measurement of a surface. C1 Natl Inst Stand & Technol, Informat Technol Lab, Stat Engn Div, Gaithersburg, MD 20899 USA. Natl Inst Stand & Technol, Mat Sci & Engn Lab, Div Met, Gaithersburg, MD 20899 USA. Natl Inst Stand & Technol, Mfg Engn Lab, Div Precis Engn, Gaithersburg, MD 20899 USA. RP Liggett, WS (reprint author), Natl Inst Stand & Technol, Informat Technol Lab, Stat Engn Div, Gaithersburg, MD 20899 USA. EM walter.liggett@nist.gov; samuel.low@nist.gov; david.pitchure@nist.gov; junfeng.song@nist.gov NR 10 TC 4 Z9 4 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 JUL-AUG PY 2000 VL 105 IS 4 BP 511 EP 533 DI 10.6028/jres.105.041 PG 23 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 357EG UT WOS:000089485100002 PM 27551619 ER PT J AU Lucas, LL AF Lucas, LL TI Massic activity ratios of the NBS/NIST tritiated-water standards issued between 1954 and 1999 SO JOURNAL OF RESEARCH OF THE NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY LA English DT Article DE hydrogen-3; massic activity; NBS; NIST; standards; tritiated water; tritium AB As part of the preparation and calibration of three new National Institute of Standards and Technology (NIST) tritiated-water radioactivity Standard Reference Materials (SRMs), the massic-activity (activity of the sample divided by the mass of the sample) ratios of all of the available NBS/ NIST tritiated-water SRMs issued between 1954 and 1999 were measured using liquid-scintillation (LS) counting. Four of the tritiated-water standards (SRMs 4361, 4926B, 4927C, and 4927D) were not available for measurement. All of the other tritiated-water standards (SRMs 4361B, 4361C, 4926, 4926C, 4926D, 4926E, 4927, 4927B, 4927E, and 4927F) were available, having been stored in flame-sealed glass ampoules. Where possible, massic-activity ratios measured by liquid-scintillation counting are compared with massic-activity ratios calculated from gravimetric dilution factors. The agreement is well within the stated uncertainties. For two of the tritiated-water standards that were not available for measurement (SRMs 4361 and 4926B), massic-activity ratios calculated from gravimetric dilution factors are available. C1 Natl Inst Stand & Technol, Phys Lab, Ionizing Radiat Div, Gaithersburg, MD 20899 USA. RP Lucas, LL (reprint author), Natl Inst Stand & Technol, Phys Lab, Ionizing Radiat Div, Gaithersburg, MD 20899 USA. EM larry.lucas@nist.gov NR 5 TC 3 Z9 3 U1 0 U2 3 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 JUL-AUG PY 2000 VL 105 IS 4 BP 535 EP 539 DI 10.6028/jres.105.042 PG 5 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 357EG UT WOS:000089485100003 PM 27551620 ER PT J AU Lucas, LL Unterweger, MP AF Lucas, LL Unterweger, MP TI Comprehensive review and critical evaluation of the half-life of tritium SO JOURNAL OF RESEARCH OF THE NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY LA English DT Article DE evaluation; half-life; hydrogen-3; review; tritium ID TRITIATED-WATER STANDARDS AB As part of the preparation and calibration of three new National Institute of Standards and Technology (NIST) tritiated-water radioactivity Standard Reference Materials (SRMs), we have performed a comprehensive review and critical evaluation of the half-life of tritium (hydrogen-3). Twenty three experimentally-determined values of the half-life of tritium, reported between 1936 and 2000, were found. Six of these values were updated by later values. Two values were limits. Two values were deemed to be outliers. The 13 remaining values were evaluated in several ways. The results are compared with the results of other recent evaluations and all are found to be in good agreement. Our final recommended value for the half-life of tritium is the average of the adopted values from the four most recent evaluations, (4500 +/- 8) d, where 8 d corresponds to one standard uncertainty. C1 Natl Inst Stand & Technol, Phys Lab, Ionizing Radiat Div, Gaithersburg, MD 20899 USA. RP Lucas, LL (reprint author), Natl Inst Stand & Technol, Phys Lab, Ionizing Radiat Div, Gaithersburg, MD 20899 USA. EM larry.lucas@nist.gov; michael.unterweger@nist.gov NR 50 TC 146 Z9 157 U1 1 U2 16 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 JUL-AUG PY 2000 VL 105 IS 4 BP 541 EP 549 DI 10.6028/jres.105.043 PG 9 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 357EG UT WOS:000089485100004 PM 27551621 ER PT J AU Misakian, M AF Misakian, M TI Equations for the magnetic field produced by one or more rectangular loops of wire in the same plane SO JOURNAL OF RESEARCH OF THE NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY LA English DT Article DE equations; electronic article surveillance systems; magnetic field; metal detector; rectangular coils AB Beginning with expressions for the vector potential, the equations for calculating the magnetic flux density from up to three rectangular loops of wire in the same plane are derived. The geometry considered is the same as that found in some walk-through metal detectors and electronic article surveillance systems. Equations for more or fewer loops can be determined by inspection. A computer program for performing the magnetic field calculation is provided in an appendix. C1 Natl Inst Stand & Technol, Elect & Elect Engn Lab, Div Elect, Gaithersburg, MD 20899 USA. RP Misakian, M (reprint author), Natl Inst Stand & Technol, Elect & Elect Engn Lab, Div Elect, Gaithersburg, MD 20899 USA. EM martin.misakian@nist.gov NR 6 TC 27 Z9 27 U1 0 U2 4 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 JUL-AUG PY 2000 VL 105 IS 4 BP 557 EP 564 DI 10.6028/jres.105.045 PG 8 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 357EG UT WOS:000089485100006 PM 27551623 ER PT J AU Tang, X L'Hostis, P Xiao, Y AF Tang, X L'Hostis, P Xiao, Y TI An auto-focusing method in a microscopic testbed for optical discs SO JOURNAL OF RESEARCH OF THE NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY LA English DT Article DE auto-focus; disc testbed; optical discs; standard deviation AB An auto-focusing method in a digital image system is demonstrated that uses a standard deviation of pixel gray levels as a feedback signal. In this system, an optical microscope and a charge coupled device (CCD) camera are used to create clear pit images of optical discs. A dynamic focusing scheme is designed in the system-control software, which is able to eliminate environmental disturbances and other noises so that a fast and stable focus can be achieved. The method shows an excellent focusing accuracy. The performance and possible applications of this method are discussed. The test results for optical discs are given in this paper. C1 Natl Inst Stand & Technol, Informat Technol Lab, Gaithersburg, MD 20899 USA. RP Tang, X (reprint author), Natl Inst Stand & Technol, Informat Technol Lab, Gaithersburg, MD 20899 USA. EM xiao.tang@nist.gov; yu.xiao@nist.gov NR 2 TC 2 Z9 2 U1 1 U2 6 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 JUL-AUG PY 2000 VL 105 IS 4 BP 565 EP 569 DI 10.6028/jres.105.046 PG 5 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 357EG UT WOS:000089485100007 PM 27551624 ER PT J AU Levenson, MS Banks, DL Eberhardt, KR Gill, LM Guthrie, WF Liu, HK Vangel, MG Yen, JH Zhang, NF AF Levenson, MS Banks, DL Eberhardt, KR Gill, LM Guthrie, WF Liu, HK Vangel, MG Yen, JH Zhang, NF TI An approach to combining results from multiple methods motivated by the ISO GUM SO JOURNAL OF RESEARCH OF THE NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY LA English DT Article DE Bayes; reference materials; uncertainty AB The problem of determining a consensus value and its uncertainty from the results of multiple methods or laboratories is discussed. Desirable criteria of a solution are presented. A solution motivated by the ISO Guide to the Expression of Uncertainty in Measurement (ISO GUM) is introduced and applied in a detailed worked example. A Bayesian hierarchical model motivated by the proposed solution is presented and compared to the solution. C1 Natl Inst Stand & Technol, Informat Technol Lab, Stat Engn Div, Gaithersburg, MD 20899 USA. RP Levenson, MS (reprint author), Natl Inst Stand & Technol, Informat Technol Lab, Stat Engn Div, Gaithersburg, MD 20899 USA. EM mark.levenson@nist.gov; william.guthrie@nist.gov; hung-kang.liu@nist.gov; mark.vangel@nist.gov; james.yen@nist.gov; nien-fan.zhang@nist.gov NR 10 TC 86 Z9 86 U1 0 U2 7 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 JUL-AUG PY 2000 VL 105 IS 4 BP 571 EP 579 DI 10.6028/jres.105.047 PG 9 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 357EG UT WOS:000089485100008 PM 27551625 ER PT J AU Mielenz, KD AF Mielenz, KD TI Numerical evaluation of diffraction integrals SO JOURNAL OF RESEARCH OF THE NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY LA English DT Article DE circular aperture; diffraction; half plane; numerical integration; recursion formula; slit AB This paper describes a simple numerical integration method for diffraction integrals which is based on elementary geometrical considerations of the manner in which different portions of the incident wavefront contribute to the diffracted field. The method is applicable in a wide range of cases as the assumptions regarding the type of integral are minimal, and the results are accurate even when the wavefront is divided into only a relatively small number of summation elements. Higher accuracies can be achieved by increasing the number of summation elements and/or incorporating Simpson's rule into the basic integration formula. The use of the method is illustrated by numerical examples based on Fresnel's diffraction integrals for circular apertures and apertures bounded by infinite straight lines (slits, half planes). In the latter cases, the numerical integration formula is reduced to a simple recursion formula, so that there is no need to perform repetitive summations for every point of the diffraction profile. C1 NIST, Phys Lab, Radiometr Phys Div, Oakland, MD 21550 USA. RP Mielenz, KD (reprint author), NIST, Phys Lab, Radiometr Phys Div, Oakland, MD 21550 USA. EM kmielenz@mail.gcnet.net NR 5 TC 2 Z9 2 U1 1 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 JUL-AUG PY 2000 VL 105 IS 4 BP 581 EP 587 DI 10.6028/jres.105.048 PG 7 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 357EG UT WOS:000089485100009 PM 27551626 ER PT J AU Mielenz, KD AF Mielenz, KD TI Computation of Fresnel integrals. II SO JOURNAL OF RESEARCH OF THE NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY LA English DT Article DE computation; Fresnel integrals; rational approximations; series expansions AB This paper describes an improved method for computing Fresnel integrals with an error of less than 1 x 10(-9). The method is based on a known approximate formula for a different integral which is due to Boersma and referenced by Abramowitz and Stegun. C1 NIST, Phys Lab, Radiometr Phys Div, Oakland, MD 21550 USA. RP Mielenz, KD (reprint author), NIST, Phys Lab, Radiometr Phys Div, Oakland, MD 21550 USA. EM kmielenz@mail.gcnet.net NR 5 TC 16 Z9 16 U1 1 U2 6 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 JUL-AUG PY 2000 VL 105 IS 4 BP 589 EP 590 DI 10.6028/jres.105.049 PG 2 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 357EG UT WOS:000089485100010 PM 27551627 ER PT J AU Slifka, AJ AF Slifka, AJ TI Thermal-conductivity apparatus for steady-state, comparative measurement of ceramic coatings SO JOURNAL OF RESEARCH OF THE NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY LA English DT Article DE guarded hot plate; infrared microscope; thermal; barrier coating; thermal conductivity; yttria-stabilized-zirconia AB An apparatus has been developed to measure the thermal conductivity of ceramic coatings. Since the method uses an infrared microscope for temperature measurement, coatings as thin as 20 mu m can, in principle, be measured using this technique. This steady-state, comparative measurement method uses the known thermal conductivity of the substrate material as the reference material for heat-flow measurement. The experimental method is validated by measuring a plasma-sprayed coating that has been previously measured using an absolute, steady-state measurement method. The new measurement method has a relative standard uncertainty of about 10 %. The measurement of the plasma-sprayed coating gives 0.58 W.m(-1).K-1 which compares well with the 0.62 W.m(-1).K-1 measured using the absolute method. C1 Natl Inst Stand & Technol, Mat Sci & Engn Lab, Mat Reliabil Div, Boulder, CO 80303 USA. RP Slifka, AJ (reprint author), Natl Inst Stand & Technol, Mat Sci & Engn Lab, Mat Reliabil Div, 325 Broadway, Boulder, CO 80303 USA. EM slifka@boulder.nist.gov NR 19 TC 10 Z9 13 U1 2 U2 5 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 JUL-AUG PY 2000 VL 105 IS 4 BP 591 EP 605 DI 10.6028/jres.105.050 PG 15 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 357EG UT WOS:000089485100011 PM 27551628 ER PT J AU Yamaura, K Huang, Q Lynn, JW Erwin, RW Cava, RJ AF Yamaura, K Huang, Q Lynn, JW Erwin, RW Cava, RJ TI Synthesis, crystal structure, and magnetic order of the layered iron oxycarbonate Sr4Fe2O6CO3 SO JOURNAL OF SOLID STATE CHEMISTRY LA English DT Article DE layered oxycarbonates; Ruddlesden-Popper phases; Sr4Fe2O6CO3; powder neutron diffraction; neutron scattering ID SUPERCONDUCTORS; SERIES AB The iron oxycarbonate Sr4Fe2O6CO3 is reported. The crystal structure and magnetic order were determined by magnetic susceptibility, powder neutron diffraction, and neutron scattering studies. The structure is tetragonal between 10 and 400 K (I4/mmm, a = 3.88907(4) Angstrom and c = 27.9818(4) Angstrom at 295 K), and is related to a 4:3 type Ruddlesden-Popper phase with CO3 plaques in place of the middle layer of transition metal octahedra. The three-dimensional magnetic ordering transition temperature is 361 K, The magnetic order is antiferromagnetic within the FeO2/SrO/SrO/FeO2 blocks and ferromagnetic between blocks. (C) 2000 Academic Press. 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. RP Yamaura, K (reprint author), Princeton Univ, Dept Chem, Princeton, NJ 08540 USA. NR 8 TC 21 Z9 21 U1 2 U2 16 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 JUL PY 2000 VL 152 IS 2 BP 374 EP 380 DI 10.1006/jssc.2000.8665 PG 7 WC Chemistry, Inorganic & Nuclear; Chemistry, Physical SC Chemistry GA 332CT UT WOS:000088056400007 ER PT J AU Ravikiran, A Jahanmir, S AF Ravikiran, A Jahanmir, S TI Effect of interfacial layers on wear behavior of a dental glass-ceramic SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Article ID STEEL; ALUMINA AB Wear studies on a glass-ceramic dental restorative material were performed under two types of lubrication conditions with distilled water. In one set of experiments, the contact interface was continuously flushed with fresh water to remove the wear debris. In a second set of experiments, the water was not replaced during the testing period. Flushing resulted in a lower friction coefficient and more than twice the wear volume compared with the nonflushing condition. Examination of the worn surfaces in SEM confirmed the presence of an interfacial layer at the sliding interface for the nonflushing experiments. These results suggest that the specific conditions at the sliding interfaces and particularly the nature of interfacial layers must be considered when evaluating the tribological performance of ceramics and especially when the wear data from different studies are compared. C1 NIST, Div Ceram, Gaithersburg, MD 20899 USA. RP Ravikiran, A (reprint author), NIST, Div Ceram, Gaithersburg, MD 20899 USA. NR 12 TC 6 Z9 6 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 JUL PY 2000 VL 83 IS 7 BP 1831 EP 1833 PG 3 WC Materials Science, Ceramics SC Materials Science GA 333HF UT WOS:000088124300045 ER PT J AU Schuur, TJ Rutledge, SA AF Schuur, TJ Rutledge, SA TI Electrification of stratiform regions in mesoscale convective systems. Part I: An observational comparison of symmetric and asymmetric MCSs SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID MIDLATITUDE SQUALL LINE; 10-11 JUNE 1985; DOPPLER RADAR ANALYSIS; PRECIPITATION STRUCTURE; REFLECTIVITY STRUCTURE; KINEMATIC STRUCTURE; TRANSITION ZONE; TRAILING REGION; ICE CRYSTALS; OKLAHOMA AB The kinematic, microphysical, and electrical structures of two mesoscale convective systems (MCSs) observed during the 1991 Cooperative Oklahoma Profiler Studies (COPS91) experiment are analyzed. Profiles of the vertical electric field structure and charge density were obtained from a series of balloon-borne electric field meter (EFM) flights into each MCS. Contrasting electric field structures were found in the stratiform regions of these MCSs. In both systems, the EFM data indicate that the MCS charge structure was characterized by horizontally extensive regions of charge and charge density magnitudes on the order of what is typically observed in convective cores (less than or equal to 5 nC m(-3)). However, the vertical electric field profiles were each related to unique MCS precipitation and kinematic structures, with a five-layer charge profile (at T less than or equal to 0 degrees C) associated with the "symmetric" MCS and a simpler three-layer charge profile (at T less than or equal to 0 degrees C) associated with the "asymmetric" MCSs. The observational analysis identified several kinematic, thermodynamic, and microphysical differences between the two systems that offer at least some explanation for the observed electrical structures. First, ice particles detrained from the convective line of the symmetric MCS had much shorter "residence times" in the unfavorable growth/charging region associated with the transition zone downdraft compared to the asymmetric case. Second, upon entering the trailing stratiform region, ice particles in the symmetric system were immersed in an environment that was more conducive to in situ charging via noninductive charging mechanisms. Strong mesoscale ascent in the stratiform region of the symmetric MCS led to the presence of supercooled cloud water, and hence significant electrification. There are also indications that fallspeed differences between particle types may be responsible for producing some of the charge transitions in the electric field profiles. In contrast, strong mesoscale ascent was not present in the asymmetric case, and hence conditions were less favorable for noninductive charging. C1 Colorado State Univ, Dept Atmospher Sci, Ft Collins, CO 80523 USA. RP Schuur, TJ (reprint author), NOAA, Natl Severe Storms Lab, 1313 Halley Circle, Norman, OK 73069 USA. NR 66 TC 21 Z9 21 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 JUL 1 PY 2000 VL 57 IS 13 BP 1961 EP 1982 DI 10.1175/1520-0469(2000)057<1961:EOSRIM>2.0.CO;2 PG 22 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 329HR UT WOS:000087902000001 ER PT J AU Schuur, TJ Rutledge, SA AF Schuur, TJ Rutledge, SA TI Electrification of stratiform regions in mesoscale convective systems. Part II: Two-dimensional numerical model simulations of a symmetric MCS SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID MIDLATITUDE SQUALL LINE; SECONDARY ICE PARTICLES; BULK PARAMETERIZATION; MOUNTAIN THUNDERSTORM; MICROSCALE STRUCTURE; KINEMATIC STRUCTURE; FRONTAL RAINBANDS; WATER DROPS; CLOUD MODEL; PRECIPITATION AB Model simulations of a symmetric mesoscale convective system (MCS; observations discussed in Part I) were conducted using a 2D, time-dependent numerical model with bulk microphysics. A number of charging mechanisms were considered based on various laboratory studies. The simulations suggest that noninductive ice-ice charge transfer in the low liquid water content regime, characteristic of MCS stratiform regions, is sufficient to account for observed charge density magnitudes, and as much as 70% of the total charge in the stratiform region. The remaining 30% is contributed by charge advection from the convective region. The strong role of in situ charging is consistent with previous water budget studies, which indicate that roughly 70% of the stratiform precipitation results from condensation in the mesoscale updraft. Thus both in situ charging and charge advection (the two previously identified hypotheses) appear to be important contributors to the electrical budget of the stratiform region. The simulations also indicate that once these charge densities are achieved, the sink of charge resulting from particle fallout becomes approximately equal to the rate of charge generation. This result is consistent with the quasi-steady layered structure that is commonly observed in these systems. Two noninductive charging parameterizations are rested and both are found to reproduce some of the observed stratiform charge structures. The evaporation-condensation charging and melting charging mechanisms are also investigated, but found to be insignificant. C1 Colorado State Univ, Dept Atmospher Sci, Ft Collins, CO 80523 USA. RP Schuur, TJ (reprint author), NOAA, Natl Severe Storms Lab, 1313 Halley Circle, Norman, OK 73069 USA. NR 64 TC 28 Z9 28 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 JUL 1 PY 2000 VL 57 IS 13 BP 1983 EP 2006 DI 10.1175/1520-0469(2000)057<1983:EOSRIM>2.0.CO;2 PG 24 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 329HR UT WOS:000087902000002 ER PT J AU Maslar, JE Hurst, WS Bowers, WJ Hendricks, JH Aquino, MI AF Maslar, JE Hurst, WS Bowers, WJ Hendricks, JH Aquino, MI TI In situ Raman spectroscopic investigation of aqueous iron corrosion at elevated temperatures and pressures SO JOURNAL OF THE ELECTROCHEMICAL SOCIETY LA English DT Article ID INSITU RAMAN; FILM FORMATION; PASSIVE FILM; SUPERCRITICAL WATER; CHROMIUM-ALLOYS; PH DIAGRAMS; THIN-FILMS; IDENTIFICATION; ALPHA-FE2O3; SCATTERING AB In situ Raman spectroscopy was employed to investigate iron corrosion in air saturated water at a pressure of 25.1 MPa and temperatures from 21 to 537 degrees C. Upon heating, various combinations of Fe3O4, alpha-Fe2O3, gamma-FeOOH, and gamma-Fe2O3 were observed depending on the location on or temperature of the iron coupon. In some cases, different species were observed at the same temperature at different locations on the surface. This was attributed to oxygen concentration gradients in the solution caused by recirculation zones in the cell. The surface of the corrosion coupon changed little after it was heated to 537 degrees C. This was attributed to the formation of a relatively thick, protective oxide scale after exposure to supercritical water. The ex situ Raman spectra were very similar to the irt situ spectra obtained during cooling but different from those obtained during heating. This indicates that the corrosion layer present during cooling is similar to that observed ex situ but different from that observed during heating. Ex :situ characterization of the coupon identified a two layered structure: an inner corrosion layer consisting of Fe3O4 and alpha-Fe2O3 and an outer layer consisting of gamma-Fe2O3 and alpha-Fe2O3 (C) 2000 The Electrochemical Society. S0013-4651(99)11-105-4. All rights reserved. C1 NIST, Chem Sci & Technol Lab, Gaithersburg, MD 20899 USA. RP NIST, Chem Sci & Technol Lab, Gaithersburg, MD 20899 USA. EM jmaslar@nist.gov NR 62 TC 49 Z9 49 U1 0 U2 6 PU ELECTROCHEMICAL SOC INC PI PENNINGTON PA 65 SOUTH MAIN STREET, PENNINGTON, NJ 08534 USA SN 0013-4651 EI 1945-7111 J9 J ELECTROCHEM SOC JI J. Electrochem. Soc. PD JUL PY 2000 VL 147 IS 7 BP 2532 EP 2542 DI 10.1149/1.1393565 PG 11 WC Electrochemistry; Materials Science, Coatings & Films SC Electrochemistry; Materials Science GA 333HX UT WOS:000088125800019 ER PT J AU Swann, WC Gilbert, SL AF Swann, WC Gilbert, SL TI Pressure-induced shift and broadening of 1510-1540-nm acetylene wavelength calibration lines SO JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS LA English DT Article ID ABSORPTION-LINES; LASER-DIODES; MU-M; FREQUENCY; (C2H2)-C-13 AB We have measured the pressure-induced shift for 15 lines of the v(1) + v(3) rotational-vibrational band of acetylene (C2H2)-C-12 These lines are useful as wavelength references in the 1510-1540-nm region. We find that the pressure shift varies from +0.008(2) pm/kPa for line R1 to +0.043(2) pm/kPa for line R27, with many of the lines exhibiting a shift near +0.017 pm/kPa (or, equivalently, +2.3 x 10(-3) pm/Torr or -0.29 MHz/Torr). In addition, we have measured the pressure broadening of these lines and find that it also varies with line number and is typically similar to 0.7 pm/kPa (similar to 12 MHz/Torr). We also evaluate the line sensitivity to temperature changes and electromagnetic fields. [S0740-3224(00)01007-9]. C1 Natl Inst Stand & Technol, Elect & Elect Engn Lab, Div Optoelect, Boulder, CO 80303 USA. RP Swann, WC (reprint author), Natl Inst Stand & Technol, Elect & Elect Engn Lab, Div Optoelect, 325 Broadway, Boulder, CO 80303 USA. NR 15 TC 113 Z9 116 U1 0 U2 14 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 0740-3224 J9 J OPT SOC AM B JI J. Opt. Soc. Am. B-Opt. Phys. PD JUL PY 2000 VL 17 IS 7 BP 1263 EP 1270 DI 10.1364/JOSAB.17.001263 PG 8 WC Optics SC Optics GA 331WN UT WOS:000088041800021 ER PT J AU Ravikiran, A AF Ravikiran, A TI Wear quantification SO JOURNAL OF TRIBOLOGY-TRANSACTIONS OF THE ASME LA English DT Article ID SLIDING WEAR AB Tribology literature shows considerable scatter in the wear rate of materials obtained by pin-on-disc type of studies. The general consensus thus far hits been that this scatter is due to variations in the material properties and experimental conditions used by different investigators. However, the present paper shows that the scatter carl also arise from the way wear is quantified by popular methods such as by m(3)/m, m(3)/Nm and so on. Therefore, an improved method of wear quantification indicated as "wear index" (WI) a nondimensional quantity, has been proposed and it is expected to reduce scatter that arises from the way wear is quantified. Evidence for the improvement has been provided from the results obtained from the experiments reported in this paper as well as those reported by different researchers. Besides reducing scatter, WI is expected to improve correlation in the rear values between laboratory benchmark tests and actual industrial applications, and also that between different investigators. Hence WI is expected to enhance the general uderstanding on tribology. [S0742-4787(00)01103-6]. C1 Natl Univ Singapore, Dept Elect Engn, Singapore 119260, Singapore. RP Ravikiran, A (reprint author), NIST, Div Ceram, Gaithersburg, MD 20899 USA. NR 19 TC 7 Z9 7 U1 0 U2 5 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA THREE PARK AVE, NEW YORK, NY 10016-5990 USA SN 0742-4787 J9 J TRIBOL-T ASME JI J. Tribol.-Trans. ASME PD JUL PY 2000 VL 122 IS 3 BP 650 EP 656 DI 10.1115/1.555416 PG 7 WC Engineering, Mechanical SC Engineering GA 387KM UT WOS:000166121800026 ER PT J AU Lu, RP Morgan, BA Kavanagh, KL Powell, CJ Chen, PJ Serpa, FG Egelhoff, WF AF Lu, RP Morgan, BA Kavanagh, KL Powell, CJ Chen, PJ Serpa, FG Egelhoff, WF TI Interfacial scattering of hot electrons in ultrathin Au/Co films SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B LA English DT Article; Proceedings Paper CT 27th Annual Conference on the Physics and Chemistry of Semiconductor Interfaces (PCSI-27) CY JAN 16-20, 2000 CL SALT LAKE CITY, UTAH SP Amer Vacuum Soc, USA, Off Res, USN, Off Res ID SCHOTTKY-BARRIER HEIGHT; EMISSION-MICROSCOPY; GIANT MAGNETORESISTANCE; MAGNETIC MULTILAYERS; ELASTIC-SCATTERING; CARRIER TRANSPORT; METAL; SPECTROSCOPY; GAAS; SI AB We have used room-temperature, ballistic electron emission microscopy (BEEM) to measure hat-electron transport through ultrathin Au/Co multilayer structures deposited onto Si. The samples consist of Au/Co/Si or (Au/Co)(n)/Au/Si diodes, sputter deposited at 175 or 300 K, where n is the number of repeat layers. The thin-film Co attenuation length, lambda(Co), is extracted from the BEEM spectra as a function of Co thickness, in single Co layer samples. Similarly, the interface attenuation number, or the number of Co/Au interfaces required for a 1/e attenuation, is determined from the multi-interface samples. BEEM barrier heights of Au/Co/Si decrease with increasing Co thickness (for thicknesses <1 nm), as the film becomes continuous and develops a Schottky barrier for Co or CoSi2(<0.7 eV). For these diodes, lambda(Co), increases from 0.3 to 0.5 nm, each with an estimated uncertainty of 0.1 nm, when the deposition temperature is decreased from 300 to 175K. This result is associated with decreased silicide formation at the lower deposition temperature. When Co is isolated from the Si with a 2 nm Au layer, the barrier height is stable (0.82 eV), and lambda(Co), increases further to 0.8+/-0.1 nm. The lambda(Co) values are independent of electron energy over the range measurable (1-1.8 eV). The interface attenuation number was 1.8 and 25 interfaces for 0.6 and 1.2 nm total Co thickness, respectively (in structures with a constant total Au thickness of 8 nm). Thus, significant interface scattering is observed in the thinner sample and negligible scattering when the Co thickness was doubled. Further BEEM measurements on similar superlattices are being carried out to understand these results. (C) 2000 American Vacuum Society. [S0734-211X(00)08904-6]. C1 Univ Calif San Diego, Dept Elect & Comp Engn, La Jolla, CA 92093 USA. NIST, Gaithersburg, MD 20899 USA. RP Lu, RP (reprint author), Univ Calif San Diego, Dept Elect & Comp Engn, La Jolla, CA 92093 USA. RI Kavanagh, Karen/J-6914-2012; OI Kavanagh, Karen/0000-0002-3059-7528 NR 29 TC 6 Z9 6 U1 0 U2 7 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 1071-1023 J9 J VAC SCI TECHNOL B JI J. Vac. Sci. Technol. B PD JUL-AUG PY 2000 VL 18 IS 4 BP 2047 EP 2051 DI 10.1116/1.1306334 PG 5 WC Engineering, Electrical & Electronic; Nanoscience & Nanotechnology; Physics, Applied SC Engineering; Science & Technology - Other Topics; Physics GA 345UW UT WOS:000088834400045 ER PT J AU Trees, CC Clark, DK Bidigare, RR Ondrusek, ME Mueller, JL AF Trees, CC Clark, DK Bidigare, RR Ondrusek, ME Mueller, JL TI Accessory pigments versus chlorophyll a concentrations within the euphotic zone: A ubiquitous relationship SO LIMNOLOGY AND OCEANOGRAPHY LA English DT Article ID PERFORMANCE LIQUID-CHROMATOGRAPHY; NORTH-ATLANTIC; PHYTOPLANKTON PIGMENTS; MARINE-PHYTOPLANKTON; ABSORPTION; COASTAL; WATERS; OCEAN; SEA; PROCHLOROCOCCUS AB Remotely sensed chlorophyll a (CN a) concentrations are determined by the ratio of upwelled radiances within the Soret band of Chl a (443 nm) and at 550 nm. Absorption at wavelengths outside this band (>460 nm) is dominated by accessory pigments and for the successful measurement of Chl a (e.g., 490:550 nm and 520:550 nm ratios) early Coastal Zone Color Scanner investigators speculated that these accessory pigments must covary with Chl a, although routine methods to measure these pigments had not yet been developed. Nearly 7,000 (high performance liquid chromatography) pigment samples, collected within the euphotic zone, were measured to test the consistency of the relationship between accessory pigments and Chl a. Despite the various sampling periods (1985-1998) and numerous geographic locations, consistent patterns have emerged in the ratios of the log accessory pigments to log total Chl a (TCHLA = Chl a, Chl a allomer, Chl a epimer, and chlorophyllide a). There were strong log-linear relationships within cruises for these ratios with an average r(2) of 0.889. An even moro impressive relationship was observed on a global scale when all the data were combined. individual relationships were also calculated for case I and case II waters, as well as for the first optical depth (K-1), termed the remote sensing depth. There were some statistical differences between these relationships, yet on a practical sense many could be combined. Despite a wide range of environments sampled, the overall slope of the log accessory pigments:log TCHLA was found to be 0.934 with a relative-difference root-mean-square error of 28% in log accessory pigment concentrations. This global log-linearity largely explains the success in remotely sensed Chl a algorithms, even though phyroplankton populations can vary in their composition and suite of pigments. C1 San Diego State Univ, Ctr Hydroopt & Remote Sensing, San Diego, CA 92120 USA. Natl Environm Satellite Data & Informat Serv, Natl Ocean & Adm, Camp Springs, MD 20746 USA. Univ Hawaii, Dept Oceanog, Honolulu, HI 96822 USA. RP Trees, CC (reprint author), San Diego State Univ, Ctr Hydroopt & Remote Sensing, San Diego, CA 92120 USA. RI Ondrusek, Michael/F-5617-2010 OI Ondrusek, Michael/0000-0002-5311-9094 NR 45 TC 70 Z9 75 U1 4 U2 11 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 JUL PY 2000 VL 45 IS 5 BP 1130 EP 1143 PG 14 WC Limnology; Oceanography SC Marine & Freshwater Biology; Oceanography GA 341CD UT WOS:000088572700011 ER PT J AU Connell, LB AF Connell, LB TI Nuclear ITS region of the alga Heterosigma akashiwo (Chromophyta : Raphidophyceae) is identical in isolates from Atlantic and Pacific basins SO MARINE BIOLOGY LA English DT Article ID TRANSCRIBED SPACER REGIONS; RIBOSOMAL-RNA GENE; MOLECULAR DELINEATION; NUCLEOTIDE-SEQUENCES; CHLOROPHYTA; DNA; RHODOPHYTA; RDNA; PHAEOPHYCEAE; POLYSACCHARIDES AB The internal transcribed spacer (ITS) region from 19 isolates of the algal genus Heterosigma (Chromophyta: Raphidophyceae) was amplified by polymerase chain-reaction (PCR) and sequenced. Isolates were obtained from both the Atlantic and Pacific basins. including Europe, eastern North America, western North America, japan and New Zealand, This study presents evidence that all Heterosigma isolates in this study are representatives of one species (H. akashiwo). All 19 isolates, except one (LB 1005) had identical ITS sequence (98.31% similar by pairwise comparison); Isolate LB 2005 may represent a separate subspecies. Such high degree of ITS sequence identity implies that the organism has spr ead between oceanic regions ill geologically recent times, possibly by human means. In addition to those from Heterosigma spp., the ITS regions from other marine Rophidophyceae (Chattonella antiqua, C. marina, C. subsalsa, Fibrocapsa japonica, and Olisthodiscus luteus) were amplified and sequenced using PCR. Total ITS lengths differed among the Raphidophyceae (C. antiqua, 577 base pairs (bp); C., marina, 577 bp:. C. subsalsa, 579 bp; F. japonica. 830 bp; H, akashiwo, 561 and 563 bp; O, luteus, 829 bp), but 5.8S rDNA sequences were similar in size (13 to 142 bp). The high ITS sequence identity between C. antiqua and C. marina (> 99.9% by pairwise comparison) suggests the need for a taxonomic review of these species encompassing all morphological, genetic, physiological and biochemical information. Additionally, a number of cultures of Raphidophyceae were positively identified. In general, ITS comparisons among the Raphidophyceae may be most useful at the level of species determination rather than at the population level. C1 NOAA, Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, Environm Conservat Div, Seattle, WA 98112 USA. RP Connell, LB (reprint author), NOAA, Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, Environm Conservat Div, 2725 Montlake Blvd E, Seattle, WA 98112 USA. NR 57 TC 47 Z9 53 U1 0 U2 2 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 JUL PY 2000 VL 136 IS 6 BP 953 EP 960 DI 10.1007/s002270000314 PG 8 WC Marine & Freshwater Biology SC Marine & Freshwater Biology GA 338ZH UT WOS:000088452800001 ER PT J AU Lowe, TE Brill, RW Cousins, KL AF Lowe, TE Brill, RW Cousins, KL TI Blood oxygen-binding characteristics of bigeye tuna (Thunnus obesus), a high-energy-demand teleost that is tolerant of low ambient oxygen SO MARINE BIOLOGY LA English DT Review ID ACUTE TEMPERATURE-CHANGE; YELLOWFIN TUNA; KATSUWONUS-PELAMIS; SKIPJACK TUNA; RAINBOW-TROUT; PHYLOGENETIC-RELATIONSHIPS; CARDIOVASCULAR-RESPONSES; METABOLIC RATES; CARBON-DIOXIDE; BLUEFIN TUNA AB We found blood from bigeye tuna (Thunnus obesus) to have a significantly higher O-2 affinity than blood from other tunas. Its P-50 (partial pressure of oxygen, Po-2 required to roach 50% saturation) was 1.6 to 2.0 kPa (13 to 15 mmHg) when equilibrated with 0.5% CO2. Previous studies employing similar methodologies found blood from yellowfin tuna (T. albacares), skipjack tuna (Katsuwonus pelamis), and kawakawa (Euthynnus affinis) to have a P-50 of 2.8 to 3.1 kPa (21 to 23 mmHg). These observations suggest that bigeye tuna are more tolerant of low ambient oxygen than other tuna species, and support similar conclusions derived from laboratory whole-animal studies, depth-of-capture data, and directly-recorded vertical movements of fish in the open ocean. We also found the O-2 affinity of bigeye tuna blood to be essentially unaffected by a 10 C degrees open-system temperature change (as is the blood of all tuna species studied to date). The O-2 affinity of bigeye tuna blood was, however, more affected by a 10 C degrees closed-system temperature change than the blood of any tuna species yet examined. In other words, bigeye tuna blood displayed a significantly enhanced Bohr effect (change in log P-50 per unit change in plasma pH at P-50) when subjected to the inevitable changes in partial pressure of carbon dioxide (P-CO2) and plasma pH that accompany closed-system temperature shifts, than when subjected to changes in plasma pH accomplished by changing P-CO2 alone. In vivo, the resultant large decrease in O-2 affinity (i.e. the increase in P-50) that occurs as the blood of bigeye tuna is warmed during its passage through the vascular counter-current heat exchangers ensures adequate rates of O-2 off-loading in the swimming muscles of this high-energy-demand teleost. C1 Univ Hawaii Manoa, Sch Ocean & Earth Sci & Technol, Joint Inst Marine & Atmospher Res, Pelag Fisheries Res Program, Honolulu, HI 96822 USA. RP Brill, RW (reprint author), NOAA, Natl Marine Fisheries Serv, 2570 Dole St, Honolulu, HI 96822 USA. EM rbrill@honlab.nmfs.hawaii.edu NR 102 TC 50 Z9 51 U1 0 U2 22 PU SPRINGER HEIDELBERG PI HEIDELBERG PA TIERGARTENSTRASSE 17, D-69121 HEIDELBERG, GERMANY SN 0025-3162 EI 1432-1793 J9 MAR BIOL JI Mar. Biol. PD JUL PY 2000 VL 136 IS 6 BP 1087 EP 1098 DI 10.1007/s002270000255 PG 12 WC Marine & Freshwater Biology SC Marine & Freshwater Biology GA 338ZH UT WOS:000088452800014 ER PT J AU Palmisano, AN Winton, JR Dickhoff, WW AF Palmisano, AN Winton, JR Dickhoff, WW TI Tissue-specific induction of Hsp90 mRNA and plasma cortisol response in Chinook salmon following heat shock, seawater challenge, and handling challenge SO MARINE BIOTECHNOLOGY LA English DT Article DE Chinook salmon; Oncorhynchus tshawytscha; heat shock; Hsp90 mRNA; cortisol; handling stress ID ONCORHYNCHUS-KISUTCH; MOLECULAR CHAPERONES; COHO SALMON; PROTEIN; STRESS; TSHAWYTSCHA; EXPRESSION; VERTEBRATE; XENOPUS AB In studying the whole-body response of chinook salmon (Oncorhynchus tshawytscha) to various stressors, we found that 5-hour exposure to elevated temperature (mean 21.6 degrees C; + 10.6 degrees C over ambient) induced a marked increase in Hsp90 messenger RNA accumulation in heart, brain, gill, muscle, liver, kidney, and tail fin tissues. The most vital tissues (heart, brain, gill, and muscle) showed the greatest Hsp90-mRNA response, with heart tissue increasing approximately 35-fold. Heat shock induced no increase in plasma cortisol. In contrast, a standard handling challenge induced high plasma cortisol levels, but no elevation in Hsp90 mRNA in any tissue, clearly separating the physiological and cellular stress responses. We saw no increase either in tissue Hsp90 mRNA levels or in plasma cortisol concentrations after exposing the fish to seawater overnight. C1 US Geol Survey, Biol Resources Div, Western Fisheries Ctr, Seattle, WA 98115 USA. Univ Washington, Sch Fisheries, Seattle, WA 98195 USA. Natl Marine Fisheries Serv, Seattle, WA 98112 USA. RP Palmisano, AN (reprint author), US Geol Survey, Biol Resources Div, Western Fisheries Ctr, 6505 NE 65th St, Seattle, WA 98115 USA. NR 38 TC 54 Z9 61 U1 1 U2 11 PU SPRINGER-VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 1436-2228 J9 MAR BIOTECHNOL JI Mar. Biotechnol. PD JUL-AUG PY 2000 VL 2 IS 4 BP 329 EP 338 PG 10 WC Biotechnology & Applied Microbiology; Marine & Freshwater Biology SC Biotechnology & Applied Microbiology; Marine & Freshwater Biology GA 346AW UT WOS:000088848800004 ER PT J AU Rice, CA Myers, MS Willis, ML French, BL Casillas, E AF Rice, CA Myers, MS Willis, ML French, BL Casillas, E TI From sediment bioassay to fish biomarker - connecting the dots using simple trophic relationships SO MARINE ENVIRONMENTAL RESEARCH LA English DT Article; Proceedings Paper CT 10th international Symposium on Pollutant Responses in Marine Organisms (PRIMO 10) CY APR 25-29, 1999 CL COLL WILLIAM & MARY, WILLIAMSBURG, VIRGINIA HO COLL WILLIAM & MARY DE sediment bioassay; biomarker; trophic transfer; contaminants; polychaete; English sole AB Two common problems in applying and interpreting invertebrate bioassays and fish biomarkers in sediment toxicology are the wide gap between significant effects concentrations determined by these two approaches, and a general lack of ecological context. We have devised an exposure system that is able to reconcile much of the disparity between invertebrate bioassay and fish biomarker results by incorporating realistic ecological processes based on deposit feeding and predator-prey interactions. This system relates the disturbance of interest (sediment contamination) to biologically meaningful effects in a resource of interest (marine flatfish) via a realistic contaminant vector (a deposit-feeding polychaete worm). In this pilot study, polychaetes (Armandia brevis) were exposed for 28 days, to clean sediments supplemented wi th benzo(a)pyrene (BaP), para-para dichlorodiphenyldichloroethylene (pp'DDE), Aroclor 1254, or field sediments collected from two sites in Puget Sound, Washington, contaminated predominantly with polcyclic aromatic hydrocarbons (PAHs) or chlorinated compounds. Exposed worms were then fed live to juvenile English sole (Pleuronectes vetulus) for 10 or 12 days. At the end of the exposure period, fish were measured for length and weight, sacrificed, and preserved for either routine histopathology and immunohistochemical analysis of cytochrome P450 1A. induction, or P-32 post-labeling determination of hepatic PAH-DNA adducts. Growth of predatory flatfish was lower than reference in all but one of eight groups fed contaminant-exposed polychaetes; however, statistically significant reductions in growth were only observed in three of these eight groups, at least in part due to low statistical power. Juvenile sole from all contaminant-exposed groups showed increased expression of CYP1A, and fish exposed to BaP-exposed worms showed clear evidence of hepatic PAH-DNA adducts. This method allows the concurrent evaluation of sediment contamination at multiple biological and ecological levels. These results indicate that sediments determined to be nontoxic by common invertebrate bioassays may have the potential to cause adverse effects at higher trophic levels. (C) 2000 Elsevier Science Ltd. All rights reserved. C1 NOAA, Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, Seattle, WA 98112 USA. RP Rice, CA (reprint author), NOAA, Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, 2725 Montlake Blvd E, Seattle, WA 98112 USA. NR 7 TC 35 Z9 39 U1 3 U2 15 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 JUL-DEC PY 2000 VL 50 IS 1-5 BP 527 EP 533 DI 10.1016/S0141-1136(00)00122-7 PG 7 WC Environmental Sciences; Marine & Freshwater Biology; Toxicology SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Toxicology GA 376ZG UT WOS:000165486700082 PM 11460745 ER PT J AU Rose, WL French, BL Reichert, WL Faisal, M AF Rose, WL French, BL Reichert, WL Faisal, M TI DNA adducts in hematopoietic tissues and blood of the mummichog (Fundulus heteroclitus) from a creosote-contaminated site in the Elizabeth River, Virginia SO MARINE ENVIRONMENTAL RESEARCH LA English DT Article; Proceedings Paper CT 10th international Symposium on Pollutant Responses in Marine Organisms (PRIMO 10) CY APR 25-29, 1999 CL COLL WILLIAM & MARY, WILLIAMSBURG, VIRGINIA HO COLL WILLIAM & MARY DE DNA adducts; hematopoietic tissues; fish; creosote; Fundulus heteroclitus; Elizabeth River (Virginia) ID P-32 POSTLABELING ANALYSIS; PERCH PERCA-FLUVIATILIS; TELEOST FISH; DAMAGE; LIVER; ENVIRONMENT; NEOPLASMS; GRADIENT; EXPOSURE; LESIONS AB Hydrophobic DNA adducts were examined in liver, anterior kidney, spleen, and blood of tumor-prone mummichog (Fundulus heterclitus) from the creosote-contaminated Atlantic Wood (AW) site (Elizabeth River, Virginia). DNA adducts eluted in a diagonal radioactive zone, characteristic of polycyclic aromatic hydrocarbon exposure, in all examined tissues of AW fish. Mummichog demonstrated significantly higher levels of DNA adducts in spleen (394+/-109 nmol adducts/mol nucleotides) than in liver (201+/-77 nmol adducts/mol nucleotides) or anterior kidney (211+/-68 nmol adducts/mol nucleotides; P=0.036). The levels of DNA adducts in the pooled blood (pool of four) were 142 nmol adducts/mol nucleotides. DNA adducts were not detected in the liver, anterior kidney, spleen and blood of fish collected from the reference site (< 2 nmol adducts/mol nucleotides). The high levels of DNA adducts detected in tissues of AW mummichog may be linked to the increased cancer incidence and immunosuppression in this population. (C) 2000 Elsevier Science Ltd. All rights reserved. C1 Virginia Inst Marine Sci, Coll William & Mary, Sch Marine Sci, Gloucester Point, VA 23062 USA. NOAA, Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, Environm Conservat Div, Seattle, WA 98112 USA. RP Faisal, M (reprint author), Virginia Inst Marine Sci, Coll William & Mary, Sch Marine Sci, Gloucester Point, VA 23062 USA. FU NIEHS NIH HHS [R01 ES05534] NR 41 TC 12 Z9 12 U1 1 U2 6 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 JUL-DEC PY 2000 VL 50 IS 1-5 BP 581 EP 589 DI 10.1016/S0141-1136(00)00252-X PG 9 WC Environmental Sciences; Marine & Freshwater Biology; Toxicology SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Toxicology GA 376ZG UT WOS:000165486700089 PM 11460753 ER PT J AU Shortt, K Shobe, J Domen, S AF Shortt, K Shobe, J Domen, S TI Comparison of dosimetry calibration factors at the NRCC and the NIST SO MEDICAL PHYSICS LA English DT Article ID ENERGY X-RAYS; DOSE WATER CALORIMETER; IONIZATION-CHAMBER; ION CHAMBERS; BEAMS; PROTOCOL; PHOTON; STANDARDS; GRAPHITE AB In early 1998, three transfer ionization chambers were used to compare the air-karma and absorbed-dose-to-water calibration factors measured by the National Research Council of Canada (NRCC) and the National Institute of Standards and Technology (NIST). The ratios between the NRCC and NIST calibration factors are 0.9950 and 1.0061 in the case of the absorbed-dose-to-water and air-kerma standards, respectively. In the case of the standard of absorbed dose to water, the combined uncertainty of the ratio between the standards of the two laboratories is about 0.6% and consequently, the observed difference of 0.5% is not significant at the one sigma level. In the case of the standard of air karma, the combined uncertainty of the ratio between the standards of the two laboratories is about 0.4%, and so the observed difference of 0.61% is significant at the one sigma level. However, this discrepancy is due to the known differences in the methods of assessing the wall correction factor at the two laboratories. Taking into account changes implemented in the standards that form the basis of the calibrations, the present results are consistent with those of the previous comparison done in 1990/91. As a direct result of these differences in the calibration factors, changing from an air-kerma based protocol following TG-21 to an absorbed-dose-to-water based protocol following TG-51, would alter the relationship between clinical dosimetry in Canada and the United States by about 1%. For clinical reference dosimetry, the change from TG-21 to TG-51 could result in an increase of up to 2% depending upon the ion chamber used, the details of the protocol followed and the source of traceability, either NRCC or NIST. (C) 2000 American Association of Physicists in Medicine. [S0094-2405(00)01007-5]. C1 Natl Res Council Canada, Ottawa, ON K1A 0R6, Canada. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Shortt, K (reprint author), Natl Res Council Canada, Ottawa, ON K1A 0R6, Canada. NR 40 TC 17 Z9 17 U1 0 U2 1 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0094-2405 J9 MED PHYS JI Med. Phys. PD JUL PY 2000 VL 27 IS 7 BP 1644 EP 1654 DI 10.1118/1.599031 PG 11 WC Radiology, Nuclear Medicine & Medical Imaging SC Radiology, Nuclear Medicine & Medical Imaging GA 337QG UT WOS:000088372700018 PM 10947268 ER PT J AU Ford, MJ AF Ford, MJ TI Effects of natural selection on patterns of DNA sequence variation at the transferrin, somatolactin, and p53 genes within and among chinook salmon (Oncorhynchus tshawytscha) populations SO MOLECULAR ECOLOGY LA English DT Article DE adaptation; nonsynonymous; Oncorhynchus; salmon; selection; transferrin ID POSITIVE DARWINIAN SELECTION; MOLECULAR EVOLUTION; NONSYNONYMOUS SUBSTITUTION; SEGREGATING SITES; MITOCHONDRIAL-DNA; RAPID EVOLUTION; ATLANTIC SALMON; 2 POPULATIONS; HOUSE MICE; II GENE AB This paper describes DNA sequence variation within and among four populations of chinook salmon (Oncorhynchus tshawytscha) at the transferrin, somatolactin and p53 genes. Patterns of variation among salmon species at the transferrin gene have been hypothesized to be shaped by positive natural selection for new alleles because the rate of nonsynonymous substitution is significantly greater than the rate of synonymous substitution. The twin goals of this study were to determine if the history of selection among salmon species at the transferrin gene is also reflected in patterns of intraspecific variation in chinook salmon, and to look for evidence of local adaptation at the transferrin gene by comparing patterns of nonsynonymous and synonymous variation among chinook salmon populations. The analyses presented here show that unlike patterns of variation between species, there is no evidence of greater differentiation among chinook salmon populations at nonsynonymous compared to synonymous sites. There is also no evidence of a reduction of within-species variation due to the hitchhiking effect at the transferrin gene, although in some populations nonsynonymous and synonymous derived mutations are both at higher frequencies than expected under a simple neutral model. Population size weighted selection coefficients (4Ns) that are consistent-with both the inter and intraspecific data range from similar to 10 to similar to 235, and imply that between 1 and 40% of new nonsynonymous mutations at the transferrin gene have been beneficial. C1 Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, Conservat Biol Div, Seattle, WA 98112 USA. RP Ford, MJ (reprint author), Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, Conservat Biol Div, 2725 Montlake Blvd E, Seattle, WA 98112 USA. RI Ford, Michael/K-3147-2012 NR 67 TC 31 Z9 33 U1 1 U2 8 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD OX2 0NE, OXON, ENGLAND SN 0962-1083 J9 MOL ECOL JI Mol. Ecol. PD JUL PY 2000 VL 9 IS 7 BP 843 EP 855 DI 10.1046/j.1365-294x.2000.00933.x PG 13 WC Biochemistry & Molecular Biology; Ecology; Evolutionary Biology SC Biochemistry & Molecular Biology; Environmental Sciences & Ecology; Evolutionary Biology GA 341FA UT WOS:000088579300002 PM 10886648 ER PT J AU Stensrud, DJ Bao, JW Warner, TT AF Stensrud, DJ Bao, JW Warner, TT TI Using initial condition and model physics perturbations in short-range ensemble simulations of mesoscale convective systems SO MONTHLY WEATHER REVIEW LA English DT Article ID LARGE-SCALE ENVIRONMENTS; PREDICTION SYSTEM; UNITED-STATES; NUMERICAL SIMULATIONS; PRECIPITATION FORECASTS; EXPLOSIVE CYCLOGENESIS; SQUALL LINE; TESTS; SKILL; PARAMETERIZATION AB Two separate numerical model ensembles are created by using model configurations with different model physical process parameterization schemes and identical initial conditions, and by using different model initial conditions from a Monte Carlo approach and the identical model configuration. Simulations from these two ensembles are investigated for two 48-h periods during which large, long-lived mesoscale convective systems develop. These two periods are chosen because, in some respects, they span the range of convective forecast problems routinely handled by operational forecasters. Calculations of the root-mean-square error, equitable threat score, and ranked probability score from both ensembles indicate that the model physics ensemble is more skillful than the initial-condition ensemble when the large-scale forcing for upward motion is weak. When the large scale forcing for upward motion is strong, the initial-condition ensemble is more skillful than the model physics ensemble. This result is consistent with the expectation that model physics play a larger role in model simulations when the large-scale signal is weak and the assumptions used within the model parameterization schemes largely determine the evolution of the simulated weather events. The variance from the two ensembles is created at significantly different rates, with the variance in the physics ensemble being produced two to six times faster during the first 12 h than the variance in the initial-condition ensemble. Therefore, within a very brief time period, the variance from the physics ensemble often greatly exceeds that produced by the initial-condition ensemble. These results suggest that varying the model physics is a potentially powerful method to use in creating an ensemble. In essence, by using different model configurations, the systematic errors of the individual ensemble members are different and, hence, this may allow one to determine a probability density function from this ensemble that is more diffuse than can be accomplished using a single model configuration. C1 NOAA, Natl Severe Storms Lab, Norman, OK 73069 USA. Univ Colorado, NOAA, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. Natl Ctr Atmospher Res, Boulder, CO 80307 USA. RP NOAA, Natl Severe Storms Lab, 1313 Halley Circle, Norman, OK 73069 USA. EM David.Stensrud@nssl.noaa.gov NR 78 TC 232 Z9 268 U1 3 U2 11 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 JUL PY 2000 VL 128 IS 7 BP 2077 EP 2107 DI 10.1175/1520-0493(2000)128<2077:UICAMP>2.0.CO;2 PN 1 PG 31 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 386JU UT WOS:000166058400004 ER PT J AU Bao, JW Wilczak, JM Choi, JK Kantha, LH AF Bao, JW Wilczak, JM Choi, JK Kantha, LH TI Numerical simulations of air-sea interaction under high wind conditions using a coupled model: A study of hurricane development SO MONTHLY WEATHER REVIEW LA English DT Article ID OCEANOGRAPHIC NOWCAST/FORECAST SYSTEM; TROPICAL CYCLONES; MESOSCALE MODEL; MEXICO; GULF; RINGS; WAVE; SPRAY; CIRCULATION; FLUXES AB In this study, a coupled atmosphere-ocean wave modeling system is used to simulate air-sea interaction under high wind conditions. This coupled modeling system is made of three well-tested model components: The Pennsylvania State University-National Center for Atmospheric Research regional atmospheric Mesoscale Model, the University of Colorado version of the Princeton Ocean Model, and the ocean surface gravity wave model developed by the Wave Model Development and Implementation Group. The ocean model is initialized using a 9-month spinup simulation forced by 6-hourly wind stresses and with assimilation of satellite sea surface temperature (SST) and altimetric data into the model. The wave model is initialized using a zero wave state. The scenario in which the study is carried out is the intensification of a simulated hurricane passing over the Gulf of Mexico. The focus of the study is to evaluate the impact of sea spray, mixing in the upper ocean, warm-core oceanic eddies shed by the Gulf Loop Current, and the sea surface wave field on hurricane development, especially the intensity. The results from the experiments with and without sea spray show that the inclusion of sea spray evaporation can significantly increase hurricane intensity in a coupled air-sea model when the part of the spray that evaporates is only a small fraction of the total spray mass. In this case the heat required for spray evaporation comes from the ocean. When the fraction of sea spray that evaporates increases, so that the evaporation extracts heat from the atmosphere and cools the lower atmospheric boundary layer, the impact of sea spray evaporation on increasing hurricane intensity diminishes. It is shown that the development of the simulated hurricane is dependent on the location and size of a warm-core anticyclonic eddy shed by the Loop Current The eddy affects the timing, rate, and duration of hurricane intensification. This dependence occurs in part due to changes in the translation speed of the hurricane, with a stower-moving hurricane being more sensitive to a warm-core eddy. The feedback from the SST change in the wake of the simulated hurricane is negative so that a reduction of SST results in a weaker-simulated hurricane than that produced when SST is held unchanged during the simulation. The degree of surface cooling is strongly dependent on the initial oceanic mixed layer (OML) depth. It is also found in this study that in order to obtain a realistic thermodynamic state of the upper ocean and not distort the evolution of the OML structure during data assimilation, care must be taken in the data assimilation procedure so as not to interfere with the turbulent dynamics of the OML. Compared with the sensitivity to the initial OML depth and the location and intensity of the warm eddy associated with the loop current, the model is found to be less sensitive to the wave-age-dependent roughness length. C1 NOAA, Environm Technol Lab, Boulder, CO 80303 USA. Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. Univ Colorado, Colorado Ctr Astrodynam Res, Dept Aerosp Engn Sci, Boulder, CO 80309 USA. RP Bao, JW (reprint author), NOAA, Environm Technol Lab, Mail Stop ET7,325 Broadway, Boulder, CO 80303 USA. NR 64 TC 109 Z9 127 U1 4 U2 24 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 JUL PY 2000 VL 128 IS 7 BP 2190 EP 2210 DI 10.1175/1520-0493(2000)128<2190:NSOASI>2.0.CO;2 PN 1 PG 21 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 386JU UT WOS:000166058400008 ER PT J AU Juang, HMH AF Juang, HMH TI The NCEP mesoscale spectral model: A revised version of the nonhydrostatic regional spectral model SO MONTHLY WEATHER REVIEW LA English DT Article ID TERRAIN-FOLLOWING COORDINATE; HYDROSTATIC-PRESSURE; EULER EQUATIONS; FORECAST MODEL; SIMULATION; FORMULATION; CONVECTION; OROGRAPHY; BOUNDARY; SYSTEM AB This paper illustrates a modified nonhydrostatic version of the National Centers for Environmental Prediction regional spectral model (RSM). This nonhydrostatic version of the RSM can simulate atmospheric motions of all scales, especially mesoscale. For simplicity, it is referred to in this paper as the mesoscale spectral model (MSM). The preliminary results of the previous version of the MSM have been published on the year of 1992, with coarse resolution in three dimensions and no model physics. A fine-resolution two-dimensional version has been tested on classical problems and published on the year of 1994. Instead of an externally determined hydrostatic coordinate as originally designed in 1992 MSM, the internally evolved hydrostatic coordinate as used in the RSM is implemented. This modification makes the MSM closer to the hydrostatic version in model structure and dynamics. Besides the hydrostatic perturbation, related to the external hydrostatic state as perturbation nesting, the nonhydrostatic perturbation related to the internally evolved hydrostatic state is introduced. The same model physics used in the RSM are used in the MSM without the hydrostatic assumption. The major numerical techniques used in the hydrostatic version are used in the MSM as well. They are spectral computation, fourth-order horizontal diffusion, time filter, and semi-implicit adjustment for perturbation. The hydrostatic state, interpolated from the hydrostatic global model, is used as the initial condition without initialization or data assimilation, and it can be integrated up to several days with reasonable predictions. Extended tests of thermal bubbles and mountain waves in very fine resolutions by this revised MSM showed its behavior to be the same as, but not superior to, those of the previous version. These results are compatible to other model results in the literature. Cases using real data with full model physics as used in the RSM show that the revised MSM has reasonable results and is superior to the previous version as compared with the RSM in a coarse horizontal grid resolution of about 50 km. Furthermore, it shows that it can be successfully nested into the hydrostatic global model at 10- to 20-fold differences in horizontal resolution with a small domain due to the well-behaved perturbation nesting over flat plains, coastal oceans, and steep mountains. C1 Natl Ctr Environm Predict, CPC, Environm Modeling Ctr, Camp Springs, MD 20746 USA. RP Juang, HMH (reprint author), Natl Ctr Environm Predict, CPC, Environm Modeling Ctr, W-NP5,World Weather Bldg,Room 806,5200 Auth Rd, Camp Springs, MD 20746 USA. NR 31 TC 22 Z9 24 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 JUL PY 2000 VL 128 IS 7 BP 2329 EP 2362 DI 10.1175/1520-0493(2000)128<2329:TNMSMA>2.0.CO;2 PN 2 PG 34 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 386JV UT WOS:000166058500001 ER PT J AU Mass, CF Steenburgh, TJ AF Mass, CF Steenburgh, TJ TI An observational and numerical study of an orographically trapped wind reversal along the west coast of the United States SO MONTHLY WEATHER REVIEW LA English DT Article ID MESOSCALE RIDGES; LOWER ATMOSPHERE; BOUNDARY-LAYER; CATALINA EDDY; WARM-SEASON; DYNAMICS; MODEL; DISTURBANCE; EVOLUTION; MOUNTAINS AB Observational analyses and a high-resolution simulation using The Pennsylvania State University-NCAR Mesoscale Model Version 5 (MM5) were used to describe the coastally trapped wind reversal of 19-21 July 1994. Major findings include the following. The event was initiated and controlled by changes in the synoptic-scale flow, and particularly by the development of offshore flow over the coastal terrain of Oregon. Although synoptic control was dominant, blocking of the inversion-capped marine layer and mesoscale coastal pressure ridging were important n ponents of the event. The synoptic evolution associated with the trapped reversal was characterized by a shift from climatological near-zonal 500-mb flow to high-amplitude upper-level ridging over the eastern Pacific. As this upper ridge moved northeastward, the 850-mb flow over Oregon became northeasterly and then southeasterly, and 850-mb heights fell over western Oregon. The combination of falling heights aloft and increasing low-level offshore flow, with associated downslope subsidence warming and offshore advection of warm continental air, resulted in sea level pressure falling along the Oregon coast and the northward extension of the California thermal trough into northern Oregon. The extension of the thermal trough caused a reversal of the alongshore pressure gradient along the Oregon coast, so that pressure increased to the south, as well as the attenuation or reversal of the normal cross-shore pressure gradient over the coastal waters. As the coastal trough intensified, there was an increase in nearly geostrophic, onshore-directed coastal flow, with appreciable blocking and deflection of the inversion-capped marine layer by the coastal terrain. With an increase in the northward-directed pressure gradient force due to the troughing to the north, and a lesser contribution from damming of the marine air on the coastal terrain, the blocked low-level winds developed a coastally trapped southerly component over a considerable expanse of the southern and central Oregon coast. Before wind reversal, the northerly flow over the coast was nearly geostrophic. After the coastal winds turned southerly, near-geostrophic balance in the cross-shore direction was established, with the offshore-directed pressure gradient force associated with the coastal pressure ridge balanced by the eastward-directed Coriolis force associated with the southerly flow. In contrast, the momentum balance in the alongshore direction was highly ageostrophic after wind reversal, with near-antitriptic balance close to shore between the northward-directed pressure gradient force and friction, while farther offshore the pressure gradient and Lagrangian accelerations were roughly in balance. The offshore scale of the blocking within the marine layer was less than in the stable layer immediately above, a result consistent with previous theoretical and modeling studies. This difference in offshore blocking scale resulted in the offshore wind reversal occurring in the stable layer aloft before it occurred at the surface. C1 Univ Washington, Dept Atmospher Sci, Seattle, WA 98195 USA. Univ Utah, NOAA, Cooperat Inst Reg Predict, Salt Lake City, UT USA. Univ Utah, Dept Meteorol, Salt Lake City, UT USA. RP Mass, CF (reprint author), Univ Washington, Dept Atmospher Sci, Box 351640, Seattle, WA 98195 USA. NR 36 TC 11 Z9 11 U1 0 U2 3 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 JUL PY 2000 VL 128 IS 7 BP 2363 EP 2396 DI 10.1175/1520-0493(2000)128<2363:AOANSO>2.0.CO;2 PN 2 PG 34 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 386JV UT WOS:000166058500002 ER PT J AU Lo, F Hendon, HH AF Lo, F Hendon, HH TI Empirical extended-range prediction of the Madden-Julian oscillation SO MONTHLY WEATHER REVIEW LA English DT Article ID TROPICAL INTRASEASONAL OSCILLATION; OUTGOING LONGWAVE RADIATION; 40-50 DAY OSCILLATION; CIRCULATION ANOMALIES; 60-DAY OSCILLATION; PATTERN-ANALYSIS; NORTHERN WINTER; FGGE YEAR; CONVECTION; FLUCTUATIONS AB An empirical model that predicts the evolution of the Madden-Julian oscillation (MJO) in outgoing longwave radiation (OLR) and 200-mb streamfunction is developed, The model is based on the assumption that the MJO can be well represented by a pair of empirical orthogonal functions (EOFs) of OLR and three EOFs of streamfunction. With an eye toward using this model in real time, these EOFs are determined with data only subjected to filtering that can be applied in near-real time. Stepwise lag regression is used to develop the model on Il winters of dependent data. The predictands are the leading two principal components (PCs) of OLR and the leading: three PCs of streamfunction. The model is validated with five winters of independent data and is also compared to dynamic extended range forecasts (DERFs) made with the National Centers for Environmental Prediction's Medium Range Forecast (MRF) model. Skillful forecasts of the MJO in OLR and streamfunction with the empirical model are achieved out to about 15 days. Initial skill arises from autocorrelation of the PCs. Subsequent skill beyond about 1 week arises primarily from the cross correlation with the other PCs that define the MJO. Inclusion of PCs not associated with the MJO as predictors appears not to reliably improve skill. Skill is found to be substantially better when the MO is active at the initial condition than when it is inactive. The empirical forecasts are also found to be more skillful than DERF from the MRF for lead times Longer than about I week. Furthermore, skill of DERF from the MRF is found to be better when the MJO is quiescent than when it is active at the initial condition. It is suggested that significant improvement of tropical DERF could be achieved by improvement of the representation of the MJO in the dynamic forecast model. C1 Climate Diagnost Ctr, NOAA, CIRES, Boulder, CO 80303 USA. RP Hendon, HH (reprint author), Climate Diagnost Ctr, NOAA, CIRES, 325 Broadway,R-E-CD, Boulder, CO 80303 USA. NR 29 TC 67 Z9 76 U1 0 U2 3 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 JUL PY 2000 VL 128 IS 7 BP 2528 EP 2543 DI 10.1175/1520-0493(2000)128<2528:EERPOT>2.0.CO;2 PN 2 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 386JV UT WOS:000166058500009 ER PT J AU Rogers, RF Fritsch, JM Lambert, WC AF Rogers, RF Fritsch, JM Lambert, WC TI A simple technique for using radar data in the dynamic initialization of a mesoscale model SO MONTHLY WEATHER REVIEW LA English DT Article ID 4-DIMENSIONAL DATA ASSIMILATION; NUMERICAL WEATHER PREDICTION; LARGE-SCALE ENVIRONMENTS; CONVECTIVE SYSTEMS; IMAGERY DATA; PRECIPITATION; PARAMETERIZATION; SIMULATIONS; RESOLUTION; MOISTURE AB A simple technique for using radar reflectivity to improve model initialization is presented. Unlike previous techniques, the scheme described here does not infer rain rates and heating profiles from assumed relationships between remotely sensed variables and precipitation rates. Rather, the radar data are only used to tell the model when and where deep moist convection is occurring. This information is then used to activate the model's convective parameterization scheme in the grid elements where convection is observed. This approach has the advantage that the convective precipitation rates and heating profiles generated by the convective parameterization are compatible with the local (grid element) environment. The premise is that if convection is forced to develop when and where it is observed during a data assimilation period, convectively forced modifications to the environment wilt he in the correct locations at the model initial forecast time and the resulting forecast will be more accurate. Three experiments illustrating how the technique is applied in the simulation of deep convection in a warm-season environment are presented: a control run in which no radar data are assimilated, and two additional runs where radar data are assimilated for 12 h in one run and 24 h in the other. The results indicate that assimilating radar data can improve a model's description of the mesoscale environment during the preforecast time period, thereby resulting in an improved forecast of precipitation and the mesoscale environment. C1 NOAA, Atlantic Oceanog & Meteorol Lab, Hurrican Res Div, Miami, FL 33149 USA. Penn State Univ, Dept Meteorol, University Pk, PA 16802 USA. ENSCO Inc, Cocoa Beach, FL USA. RP Rogers, RF (reprint author), NOAA, Atlantic Oceanog & Meteorol Lab, Hurrican Res Div, 4301 Rickenbacker Causeway, Miami, FL 33149 USA. RI Rogers, Robert/I-4428-2013 NR 34 TC 22 Z9 27 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 JUL PY 2000 VL 128 IS 7 BP 2560 EP 2574 DI 10.1175/1520-0493(2000)128<2560:ASTFUR>2.0.CO;2 PN 2 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 386JV UT WOS:000166058500011 ER PT J AU Mofjeld, HO Gonzalez, FI Bernard, EN Newman, JC AF Mofjeld, HO Gonzalez, FI Bernard, EN Newman, JC TI Forecasting the heights of later waves in Pacific-wide tsunamis SO NATURAL HAZARDS LA English DT Article DE short-term tsunami forecasting; Pacific-wide tsunamis; exponential tsunami decay; statistical modeling ID SEA-LEVEL FLUCTUATIONS; EARTHQUAKES AB A method is derived to forecast the extreme heights of later waves in Pacific-wide tsunamis, for locations in the vicinity of real-time reporting tide gages. The forecast for wave peaks has the form eta(F)(t) = eta(B)(t) + eta(e)(t), where eta(e) = A sigma exp[-(t - t(o))/tau]. Here, the forecast begins at time t = t(o), which is 4 h after tsunami detection at a tide gage, sigma is the standard deviation of tsunami-band fluctuations observed in the 2-h time interval before the forecast begins, eta(B) is a background water level prediction that includes the tides and lower frequency oscillations, tau = 48 h is an e-folding decay constant, and A = 3.0 is a constant coefficient. Placing a minus sign in front of eta(e) provides a forecast for wave troughs. This form for the forecast, and the values of the parameters, are justified using probability theory and Monte Carlo simulations based on 3000 synthetic tsunami time series. The method is then tested successfully (i.e., agreement within 0.5 m) against six past Pacific-wide tsunamis, as observed at U.S. tide gages. These case studies include the five major tsunamis to produce loss of life and/or substantial damage to U.S. coastal communities during the Twentieth Century. The sixth study is the 1994 Shikotan tsunami, which is the latest Pacific-wide tsunami to trigger tsunami warnings for U.S. regions. Algorithms for detecting local tsunami onset and generating forecasts are given in an appendix, together with a description of the wavelet method used to generate the synthetic tsunami series. C1 NOAA, Pacific Marine Environm Lab, Seattle, WA 98115 USA. RP Mofjeld, HO (reprint author), NOAA, Pacific Marine Environm Lab, Bldg 3,7600 Sand Point Way NE, Seattle, WA 98115 USA. EM mofjeld@pmel.noaa.gov RI Newman, Jean/K-6638-2015 NR 17 TC 11 Z9 11 U1 0 U2 5 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0921-030X J9 NAT HAZARDS JI Nat. Hazards PD JUL PY 2000 VL 22 IS 1 BP 71 EP 89 DI 10.1023/A:1008198901542 PG 19 WC Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences; Water Resources SC Geology; Meteorology & Atmospheric Sciences; Water Resources GA 359KQ UT WOS:000089610400005 ER PT J AU Bossy, J Andersen, KH Cook, JC Randl, OR AF Bossy, J Andersen, KH Cook, JC Randl, OR TI High-resolution neutron measurements of the roton line shape under pressure SO PHYSICA B LA English DT Article; Proceedings Paper CT 22nd International Conference on Low Temperature Physics CY AUG 04-11, 1999 CL HELSINKI UNIV TECHNOL, HELSINKI, FINLAND SP Commiss C5 low Temp Phys, Int Union Pure & Appl Phys, Acad Finland, Helsinki Univ Technol, Int Assoc Promot Sci, Oxford Instruments Ltd, FortumCorp, Nokia Grp, Finnair Ltd, Datex Engstrom Ltd, Finnish Phys Soc, Picker Nordstar Ltd, Neuromag ltd, SAP Finland Ltd, Espoo Elect Ltd, Outokumpu Ltd, City Espoo, Finnish Acad Sci & Letters, DCA-Instruments Ltd, Vaisala Ltd HO HELSINKI UNIV TECHNOL DE dynamic structure factor; He-4 superfluid; neutron scattering AB High-resolution inelastic neutron scattering measurements of the dynamic structure factor S(q, omega) of superfluid He-4 at the roton minimum are presented. The temperature dependence of the roton energy and line width at 24 bar between 0.8 and 1.1 K are reported. (C) 2000 Elsevier Science B.V. All rights reserved. C1 CNRS, Ctr Rech Tres Basses Temp, F-38042 Grenoble 9, France. Inst Max Von Laue Paul Langevin, F-38042 Grenoble, France. Rutherford Appleton Lab, ISIS, Didcot OX11 0QX, Oxon, England. NIST, Gaithersburg, MD 20899 USA. RP Bossy, J (reprint author), CNRS, Ctr Rech Tres Basses Temp, BP 166, F-38042 Grenoble 9, France. NR 7 TC 0 Z9 0 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4526 J9 PHYSICA B JI Physica B PD JUL PY 2000 VL 284 BP 27 EP 28 DI 10.1016/S0921-4526(99)01957-2 PN 1 PG 2 WC Physics, Condensed Matter SC Physics GA 318YF UT WOS:000087311700015 ER PT J AU Rao, DV Cesareo, R Brunetti, A Gigante, GE AF Rao, DV Cesareo, R Brunetti, A Gigante, GE TI Influence of solid state environment effects on measured elastic scattering cross sections in the X-ray regime and the associated anomalous dispersion SO PHYSICA SCRIPTA LA English DT Article ID ANGLE RAYLEIGH-SCATTERING; ATOMIC FORM-FACTORS; HIGH-Z-ELEMENTS; ENERGY REGION; PHOTONS; FLUORESCENCE; 13-LESS-THAN-OR-EQUAL-TO-Z-LESS-THAN-OR-EQUAL-TO-82; COHERENT AB Experimental elastic scattering cross sections in the atomic region 21 less than or equal to Z less than or equal to 82 are measured at an angle of 90 degrees using monoenergetic unpolarised Mo K alpha radiation. The measurements are based on a new method developed to estimate the degree of monochromaticity, the efficiency of the detecting system solid angle correction and some considerations which are necessary in experiments using secondary targets as excitation sources. Unpolarised monoenergetic radiation is produced using an X-ray tube and a secondary target To reflect the data on the current knowledge, the results are compared with theoretical estimates based on form factor formalisms including the anomalous scattering factors and with the recent S-matrix values. Based on the experimental evidence, the present results indicate the influence of solid state environmental effects, the importance of anomalous corrections near thresholds, superiority of S-matrix values over form factor values, correctness of high energy limit values on measured elastic scattering cross sections. However, the comparison of the experimental results with theoretical estimates indicates the importance of numerical calculations based on the multipole expansion of the S-matrix approach and high energy limit values. C1 Abdus Salam Int Ctr Theoret Phys, I-34100 Trieste, Italy. Univ Sassari, Ist Matemat & Fis, I-07100 Sassari, Italy. Univ Rome La Sapienza, Dipartimento Fis, I-00185 Rome, Italy. RP Rao, DV (reprint author), Natl Inst Stand & Technol, Ionizing Radiat Div, Photon & Charged Particle Data Ctr, Gaithersburg, MD 20899 USA. RI brunetti, antonio/F-3370-2011; OI brunetti, antonio/0000-0002-0116-1899; Gigante, Giovanni Ettore/0000-0001-5943-9366 NR 40 TC 2 Z9 2 U1 0 U2 6 PU ROYAL SWEDISH ACAD SCIENCES PI STOCKHOLM PA PUBL DEPT BOX 50005, S-104 05 STOCKHOLM, SWEDEN SN 0281-1847 J9 PHYS SCRIPTA JI Phys. Scr. PD JUL PY 2000 VL 62 IS 1 BP 81 EP 87 DI 10.1238/Physica.Regular.062a00081 PG 7 WC Physics, Multidisciplinary SC Physics GA 332YN UT WOS:000088102100013 ER PT J AU Branning, D Grice, W Erdmann, R Walmsley, IA AF Branning, D Grice, W Erdmann, R Walmsley, IA TI Interferometric technique for engineering indistinguishability and entanglement of photon pairs SO PHYSICAL REVIEW A LA English DT Article ID PARAMETRIC DOWN-CONVERSION; 2 PHOTONS; INTERFERENCE; DISTINGUISHABILITY; INFORMATION; COHERENCE; PULSES; PUMP AB We give a detailed account of a recently introduced technique to suppress distinguishing information in the space-time component of the state vector of a pair of photons. The method works by creating interference between two possible ways for each photon to occupy any given space-time mode. Under certain conditions, this technique also allows the preparation of the two photons in a highly entangled space-time state. C1 NIST, Opt Technol Div, Gaithersburg, MD 20899 USA. So Illinois Univ, Dept Phys, Edwardsville, IL 62026 USA. USAF, Res Lab, SNDP, Griffiss AFB, NY 13441 USA. Univ Rochester, Inst Opt, Rochester, NY 14627 USA. Univ Rochester, Dept Phys & Astron, Rochester, NY 14627 USA. RP Branning, D (reprint author), NIST, Opt Technol Div, Gaithersburg, MD 20899 USA. RI Grice, Warren/L-8466-2013 NR 31 TC 20 Z9 20 U1 0 U2 4 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 JUL PY 2000 VL 62 IS 1 BP art. no. EP 013814 DI 10.1103/PhysRevA.62.013814 PG 18 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 333QB UT WOS:000088139800103 ER PT J AU Hall, JL Ye, J Ma, LS AF Hall, JL Ye, J Ma, LS TI Measurement of mirror birefringence at the sub-ppm level: Proposed application to a test of QED SO PHYSICAL REVIEW A LA English DT Article ID LASER; STABILIZATION; PARTICLES; INTERFEROMETER; FREQUENCY; PHOTON; CAVITY; PHASE AB We present detailed considerations on the achievable sensitivity in the measurement of birefringence using a high finesse optical cavity. emphasizing techniques based on frequency metrology. Alternative approaches of laser locking and cavity measurement techniques are discussed and demonstrated. High-precision measurements of the cavity mirror birefringence have led to the interesting observations of photorefractive activities on mirror surfaces. C1 Natl Inst Stand & Technol, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. Univ Colorado, Boulder, CO 80309 USA. Natl Inst Stand & Technol, Quantum Phys Div, Boulder, CO USA. E China Normal Univ, Lab Quantum Opt, Shanghai 200062, Peoples R China. RP Hall, JL (reprint author), Natl Inst Stand & Technol, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. RI Ye, Jun/C-3312-2011 NR 23 TC 27 Z9 27 U1 2 U2 9 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 JUL PY 2000 VL 62 IS 1 BP art. no. EP 013815 DI 10.1103/PhysRevA.62.013815 PG 8 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 333QB UT WOS:000088139800104 ER PT J AU Amelink, A Jones, KM Lett, PD van der Straten, P Heideman, HGM AF Amelink, A Jones, KM Lett, PD van der Straten, P Heideman, HGM TI Single-color photoassociative ionization of ultracold sodium: The region from 0 to 5 GHz SO PHYSICAL REVIEW A LA English DT Article ID 2-COLOR PHOTOASSOCIATION; ASSOCIATIVE IONIZATION; ATOMS; COLLISIONS; SPECTROSCOPY; NA-2; MOLECULE AB We have measured the rate of production of Na-2(+) ions in collisions of ultracold Na atoms held in a magneto-optical trap (MOT) as a function of probe laser detuning using a single-color probe beam. The ion rate is measured with the atoms mainly in the 3S(f = 2) level ("bright MOT'') or the 3S(f = 1) level ("dark MOT''). Usings recent experimental information about the doubly excited autoionizing states of Na-2, we find that the large structures in the first 5 GHz red of the atomic transition frequency are due to a doubly resonant excitation process with levels in the O-g(-) potential (asymptotically connected to 3S(1/2) + 3P(3/2)) as the intermediate states, and levels in the 0(u)(-) and 1(u) potentials (asymptotically connected to 3P(3/2) + 3P(3/2)) as the final autoionizing states. We can account for nearly all of the observed structure in this region of the spectra for both the bright and dark MOT. C1 Univ Utrecht, Debye Inst, Dept Atom & Interface Phys, NL-3508 TA Utrecht, Netherlands. Natl Inst Stand & Technol, Atom Phys Div, Gaithersburg, MD 20899 USA. RP Amelink, A (reprint author), Univ Utrecht, Debye Inst, Dept Atom & Interface Phys, POB 80000, NL-3508 TA Utrecht, Netherlands. RI Institute (DINS), Debye/G-7730-2014; van der Straten, Peter/H-9356-2016 NR 18 TC 5 Z9 5 U1 0 U2 2 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 JUL PY 2000 VL 62 IS 1 AR 013408 DI 10.1103/PhysRevA.62.013408 PG 8 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 333QB UT WOS:000088139800075 ER PT J AU Kuppens, SJM Corwin, KL Miller, KW Chupp, TE Wieman, CE AF Kuppens, SJM Corwin, KL Miller, KW Chupp, TE Wieman, CE TI Loading an optical dipole trap SO PHYSICAL REVIEW A LA English DT Article ID MAGNETOOPTICAL TRAP; COLLISIONAL LOSSES; SODIUM ATOMS; COLD; LASER; DEPENDENCE; VAPOR AB We present a detailed experimental study of the physics involved in transferring atoms from a magnetooptical trap (MOT) to an optical dipole trap. The loading is a dynamical process determined by a loading rate and a density dependent loss rate. The loading rate depends on cooling and the flux of atoms into the trapping volume, and the loss rate is due to excited state collisions induced by the MOT light fields. From this study we found ways to optimize the loading of the optical dipole trap. Key ingredients for maximum loading are found to be a reduction of the hyperfine repump intensity, increased detuning of the MOT light, and a displacement of the optical dipole trap center with respect to the MOT. A factor of 2 increase in the number of loaded atoms is demonstrated by using a hyperfine repump beam with a shadow in it. In this way we load 8 X 10(6) Rb-85 atoms into a 1 mK deep optical dipole trap with a waist of 58 mu m, which is 40% of the atoms initially trapped in the MOT. C1 Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. Natl Inst Stand & Technol, Boulder, CO 80309 USA. Univ Michigan, Dept Phys, Ann Arbor, MI 48109 USA. RP Kuppens, SJM (reprint author), Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. RI Corwin, Kristan/A-1331-2013 NR 29 TC 93 Z9 94 U1 4 U2 16 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 JUL PY 2000 VL 62 IS 1 AR 013406 DI 10.1103/PhysRevA.62.013406 PG 13 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 333QB UT WOS:000088139800073 ER PT J AU Mies, FH Raoult, M AF Mies, FH Raoult, M TI Analysis of threshold effects in ultracold atomic collisions SO PHYSICAL REVIEW A LA English DT Article ID QUANTUM-DEFECT THEORY; BOSE-EINSTEIN CONDENSATION; DIATOMIC-MOLECULES; FESHBACH RESONANCE; SCATTERING-THEORY; RELAXATION RATES; COLD COLLISIONS; GENERAL-FORM; STATE; ENERGY AB At the ultracold temperatures which occur in cold atom traps and Bose-Einstein condensates, only a few partial waves contribute to the scattering of ground-state alkali-metal atoms, and cross sections are extremely sensitive to threshold effects. We present an analysis of these threshold effects, using a generalized multichannel quantum defect theory (GMQDT) to construct a close-coupled scattering wave function which is analytic in energy across thresholds. We illustrate the theory using the hyperfine transitions in Na + Na collisions, and show that it gives results completely equivalent to the usual close-coupled cross sections. The virtue of the GMQDT is that it treats both open and closed channels on an equal footing, and all interchannel dynamics is summarized in a single real symmetric matrix Y(E) which is essentially constant across thresholds (and often over excursions of energy which exceed the hyperfine splittings). The multichannel threshold energy behavior can then be related to calculable properties of the individual channels that are being closed. Many of the smaller spin depolarization cross sections are determined by very long-range alpha(2)/R-3 spin-spin interactions which are not well treated by GMQDT, and we correct these specific elements with a perturbative distorted-wave approximation which yields the observed threshold dependences and brings the GMQDT into perfect agreement with the exact close-coupled results. C1 Natl Inst Stand & Technol, Div Atom Phys, Gaithersburg, MD 20899 USA. Univ Paris 11, Photophys Mol Lab, F-91405 Orsay, France. RP Mies, FH (reprint author), Natl Inst Stand & Technol, Div Atom Phys, Gaithersburg, MD 20899 USA. NR 61 TC 53 Z9 53 U1 0 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 JUL PY 2000 VL 62 IS 1 AR 012708 DI 10.1103/PhysRevA.62.012708 PG 19 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 333QB UT WOS:000088139800057 ER PT J AU Starr, FW Nielsen, JK Stanley, HE AF Starr, FW Nielsen, JK Stanley, HE TI Hydrogen-bond dynamics for the extended simple point-charge model of water SO PHYSICAL REVIEW E LA English DT Article ID DEPOLARIZED RAYLEIGH-SCATTERING; LENNARD-JONES MIXTURE; ELASTIC NEUTRON-SCATTERING; KINETIC GLASS-TRANSITION; LONG-TIME REGIME; SUPERCOOLED WATER; LIQUID WATER; MOLECULAR-DYNAMICS; COUPLING THEORY; SLOW DYNAMICS AB We study hydrogen-bond dynamics in liquid water at low temperatures using molecular dynamics simulations. We analyze the dynamics using energetic and geometric definitions of a hydrogen bond, and employ two analysis methods: (i) a history-dependent correlation function, related to the distribution of bond lifetimes, and (ii) a history-independent correlation function. For method (i) we find an approximately Arrhenius temperature dependence of the bond lifetime, and find that the distribution of bond lifetimes is extremely sensitive to the choice of bond definition. For method (ii) we find-independent of bond definition-that the dynamics are consistent with the predictions of the mode-coupling theory, suggesting that the slow dynamics of hydrogen bonds can be explained in the same framework as standard transport quantities. Our results allow us to clarify the significance of the choice of both bond definition and analysis technique. C1 Boston Univ, Ctr Polymer Studies, Ctr Computat Sci, Boston, MA 02215 USA. Boston Univ, Dept Phys, Boston, MA 02215 USA. Univ Roskilde, Dept Math & Phys, DK-4000 Roskilde, Denmark. RP Starr, FW (reprint author), NIST, Div Polymers, Gaithersburg, MD 20899 USA. RI Nielsen, Johannes/F-2697-2011; Starr, Francis/C-7703-2012 OI Nielsen, Johannes/0000-0002-4185-8041; NR 88 TC 116 Z9 117 U1 0 U2 15 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 JUL PY 2000 VL 62 IS 1 BP 579 EP 587 DI 10.1103/PhysRevE.62.579 PN A PG 9 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA 335YG UT WOS:000088274100077 ER PT J AU Kautz, RL Sullivan, DB AF Kautz, RL Sullivan, DB TI James Edward Zimmerman - Obituary SO PHYSICS TODAY LA English DT Biographical-Item C1 Natl Inst Stand & Technol, Boulder, CO USA. RP Kautz, RL (reprint author), Natl Inst Stand & Technol, 325 Broadway, Boulder, CO USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0031-9228 J9 PHYS TODAY JI Phys. Today PD JUL PY 2000 VL 53 IS 7 BP 70 EP 71 DI 10.1063/1.1292491 PG 2 WC Physics, Multidisciplinary SC Physics GA 331BP UT WOS:000087997700017 ER PT J AU Hayward, E Motz, JW AF Hayward, E Motz, JW TI Michael Danos - Obituary SO PHYSICS TODAY LA English DT Biographical-Item C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Hayward, E (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0031-9228 J9 PHYS TODAY JI Phys. Today PD JUL PY 2000 VL 53 IS 7 BP 72 EP 72 DI 10.1063/1.1292493 PG 1 WC Physics, Multidisciplinary SC Physics GA 331BP UT WOS:000087997700019 ER PT J AU Zhang, H Huang, K Li, Z Banerjei, L Fisher, KE Grishin, NV Eisenstein, E Herzberg, O AF Zhang, H Huang, K Li, Z Banerjei, L Fisher, KE Grishin, NV Eisenstein, E Herzberg, O TI Crystal structure of YbaK protein from Haemophilus influenzae (HI1434) at 1.8 angstrom resolution: Functional implications SO PROTEINS-STRUCTURE FUNCTION AND GENETICS LA English DT Article DE structural genomics; hypothetical proteins; X-ray crystallography; C-lectin fold; circular permutation ID TRANSFER-RNA SYNTHETASES; ESCHERICHIA-COLI; MACROMOLECULAR STRUCTURES; SALMONELLA-TYPHIMURIUM; ANOMALOUS DIFFRACTION; BINDING PROTEIN; SEQUENCE; ENDOSTATIN; REFINEMENT; REVEALS AB Structural genomics of proteins of unknown function most straightforwardly assists with assignment of biochemical activity when the new structure resembles that of proteins whose functions are known. When a new fold is revealed, the universe of known folds is enriched, and once the function is determined by other means, novel structure-function relationships are established. The previously unannotated protein HI1434 from LT. influenzae provides a hybrid example of these two paradigms. It is a member of a microbial protein family, labeled in SwissProt as YbaK and ebsC. The crystal structure at 1.8 Angstrom resolution reported here reveals a fold that is only remotely related to the C-lectin fold, in particular to endostatin, and thus is not sufficiently similar to imply that YbaK proteins are saccharide binding proteins. However, a crevice that may accommodate a small ligand is evident, The putative binding site contains only one invariant residue, Lys46, which carries a functional group that could play a role in catalysis, indicating that YbaK is probably not an enzyme. Detailed sequence analysis, including a number of newly sequenced microbial organisms, highlights sequence homology to an insertion domain in prolyl-tRNA synthetases (proRS) from prokaryote, a domain whose function is unknown. A HI1434-based model of the insertion domain shows that it should also contain the putative binding site. Being part of a tRNA synthetases, the insertion domain is likely to be involved in oligonucleotide binding, with possible roles in recognition/discrimination or editing of prolyl-tRNA. By analogy, YbaK may also play a role in nucleotide or oligonucleotide binding, the nature of which is yet to be determined. (C) 2000 Wiley-Liss, Inc. C1 Univ Maryland, Inst Biotechnol, Ctr Adv Res Biotechnol, Rockville, MD 20850 USA. Inst Genomic Res, Rockville, MD USA. NIH, Natl Ctr Biotechnol Informat, Natl Lib Med, Bethesda, MD 20892 USA. Univ Maryland Baltimore Cty, Dept Chem & Biochem, Baltimore, MD 21228 USA. NIST, Gaithersburg, MD 20899 USA. RP Herzberg, O (reprint author), Univ Maryland, Inst Biotechnol, Ctr Adv Res Biotechnol, 9600 Gudelsky Dr, Rockville, MD 20850 USA. FU NIGMS NIH HHS [P01 GM57890] NR 58 TC 40 Z9 42 U1 0 U2 1 PU WILEY-LISS PI NEW YORK PA DIV JOHN WILEY & SONS INC, 605 THIRD AVE, NEW YORK, NY 10158-0012 USA SN 0887-3585 J9 PROTEINS JI Proteins PD JUL 1 PY 2000 VL 40 IS 1 BP 86 EP 97 DI 10.1002/(SICI)1097-0134(20000701)40:1<86::AID-PROT100>3.0.CO;2-Y PG 12 WC Biochemistry & Molecular Biology; Biophysics SC Biochemistry & Molecular Biology; Biophysics GA 320QN UT WOS:000087412000010 PM 10813833 ER PT J AU Gogos, A Jantz, D Senturker, S Richardson, D Dizdaroglu, M Clarke, ND AF Gogos, A Jantz, D Senturker, S Richardson, D Dizdaroglu, M Clarke, ND TI Assignment of enzyme substrate specificity by principal component analysis of aligned protein sequences: An experimental test using DNA glycosylase homologs SO PROTEINS-STRUCTURE FUNCTION AND GENETICS LA English DT Article DE substrate specificity; genome annotation; principal component analysis; DNA glycosylase ID COLI ENDONUCLEASE-III; C-TERMINAL DOMAIN; ESCHERICHIA-COLI; SACCHAROMYCES-CEREVISIAE; BASE-EXCISION; OGG1 GENE; ALKA GENE; SCHIZOSACCHAROMYCES-POMBE; MOLECULAR-CLONING; MISMATCH REPAIR AB We have studied the relationship between amino acid sequence and substrate specificity in a DNA glycosylase family by characterizing experimentally the specificity of four new members of the family. We show that principal component analysis (PCA) of the sequence family correctly predicts the substrate specificity of one of the novel homologs even though conventional sequence analysis methods fail to group this homolog with other sequences of the same specificity. PCA also suggested, correctly, that another homolog characterized previously differs in its specificity from those sequences with which it clusters by conventional criteria. These results suggest that principal component analysis of sequence families can be a useful tool in annotating genome sequences when there is ambiguity concerning which subfamily a new homolog belongs to. Published 2000 Wiley-Liss, Inc.(dagger) C1 Johns Hopkins Sch Med, Dept Biophys & Biophys Chem, Baltimore, MD 21205 USA. NIST, Chem Sci & Technol Lab, Gaithersburg, MD 20899 USA. Inst Genome Res, Rockville, MD USA. RP Clarke, ND (reprint author), Johns Hopkins Sch Med, Dept Biophys & Biophys Chem, 725 N Wolfe St, Baltimore, MD 21205 USA. RI Clarke, Neil/D-9613-2014 NR 44 TC 9 Z9 10 U1 0 U2 2 PU WILEY-LISS PI NEW YORK PA DIV JOHN WILEY & SONS INC, 605 THIRD AVE, NEW YORK, NY 10158-0012 USA SN 0887-3585 J9 PROTEINS JI Proteins PD JUL 1 PY 2000 VL 40 IS 1 BP 98 EP 105 DI 10.1002/(SICI)1097-0134(20000701)40:1<98::AID-PROT110>3.0.CO;2-S PG 8 WC Biochemistry & Molecular Biology; Biophysics SC Biochemistry & Molecular Biology; Biophysics GA 320QN UT WOS:000087412000011 PM 10813834 ER PT J AU Anderson, JL Ploshay, JJ AF Anderson, JL Ploshay, JJ TI Impact of initial conditions on seasonal simulations with an atmospheric general circulation model SO QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY LA English DT Article DE ensembles; predictability; seasonal forecasting ID DATA ASSIMILATION SYSTEM; SURFACE-TEMPERATURE; SOIL-MOISTURE; POTENTIAL PREDICTABILITY; ENSEMBLE PREDICTION; ENSO PREDICTION; GCM SIMULATIONS; SPECTRAL MODEL; COUPLED MODEL; FORECASTS AB Many previous studies have examined the use of very long integrations of atmospheric general circulation models (AGCMs) forced by observed sea surface temperatures (SSTs) as proxies for seasonal atmospheric predictions. These long simulations explore a boundary-value problem in which significant deviations from the model's long-term climatology must be a result of the SST forcing. Seasonal lead simulations starting with observed initial conditions (ICs) for the atmosphere and land surface while retaining observed SST forcing are an intermediate step between the pure boundary-value problem and the pure initial-value forecast problem in which SSTs are also predicted. As part of the Dynamical Seasonal Prediction (DSP) experiment, an ensemble of AGCM integrations with observed atmospheric ICs and model climatology land surface ICs was integrated from mid-December through March for 16 years. These DSP simulation ensembles are compared to ensembles of long boundary-value simulations from the same AGCM in a perfect-model setting (no comparisons of simulations to observations are attempted). Significant differences must be due to the impact of the DSP ICs. Surprisingly large and long-lived differences are found in both the mean and the variance of the ensembles. Many appear to occur because the ICs of the DSP runs are inconsistent with the AGCM climatology; an extended period of model 'spin-up' is the result. Some differences are related to local impacts of the land surface ICs while others, like shifts in the distribution of tropical precipitation and a cooling of the northern hemisphere, are less obviously related to the ICs. The results suggest that care will be needed when inserting observed ICs into seasonal predictions in order to avoid the long-term effects of model spin-up. C1 Princeton Univ, US Dept Commerce, Natl Ocean & Atmospher Adm, Geophys Fluid Dynam Lab,Environm Res Labs, Princeton, NJ 08542 USA. RP Anderson, JL (reprint author), Princeton Univ, US Dept Commerce, Natl Ocean & Atmospher Adm, Geophys Fluid Dynam Lab,Environm Res Labs, POB 308, Princeton, NJ 08542 USA. NR 54 TC 8 Z9 9 U1 0 U2 1 PU ROYAL METEOROLOGICAL SOC PI READING PA 104 OXFORD ROAD, READING RG1 7LJ, BERKS, ENGLAND SN 0035-9009 J9 Q J ROY METEOR SOC JI Q. J. R. Meteorol. Soc. PD JUL PY 2000 VL 126 IS 567 BP 2241 EP 2264 DI 10.1256/smsqj.56712 PN B PG 24 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 350HG UT WOS:000089094500013 ER PT J AU Lankosz, M Sieber, J AF Lankosz, M Sieber, J TI A simple microbeam profiling technique for x-ray optics SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article AB Enhancement of the quality of images or maps obtained using micro x-ray fluorescence spectrometry requires knowledge of the flux distribution profile of the primary x-ray beam. A simple procedure based on a wire scan was developed for the determination of an x-ray microbeam profile. This technique is simple and can be used for a given excitation/detection geometry without any change in spectrometer configuration. However, the result of such a scan is a convolution of the beam profile with the shape of the wire. To restore the actual distribution of photon flux density, a nonlinear least-squares procedure was adapted to model the profile using a parametric function to describe the flux distribution. Among the algorithms tested, a sigmoid function was found to be the best for describing the beam profile. The results of calculations were verified by measurements using a charge coupled device camera. Reasonably good agreement was obtained between the two different techniques. The results of this work confirmed that a wire scan combined with a mathematical restoration procedure is useful for describing the actual profile of an x-ray microbeam created using a pinhole collimator. An advantage is that the microbeam profile is calculated at the location of the measured samples. The results indicated that the chi(2) value could be used to select the optimum function to describe the microbeam profile. The procedure can also be used to evaluate the quality of a pinhole collimator. We plan to use measured microbeam profiles in combination with mathematical procedures to improve the spatial resolution of linear scans of patterned samples. (C) 2000 American Institute of Physics. [S0034-6748(00)01107-2]. C1 Stanislaw Staszic Univ Min & Met, Fac Phys & Nucl Tech, PL-30059 Krakow, Poland. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Lankosz, M (reprint author), Stanislaw Staszic Univ Min & Met, Fac Phys & Nucl Tech, Al Mickiewicza 30, PL-30059 Krakow, Poland. NR 8 TC 3 Z9 4 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD JUL PY 2000 VL 71 IS 7 BP 2640 EP 2643 DI 10.1063/1.1150669 PG 4 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 329KU UT WOS:000087906800003 ER PT J AU Lawall, J Kessler, E AF Lawall, J Kessler, E TI Michelson interferometry with 10 pm accuracy SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article ID HETERODYNE INTERFEROMETRY; PERIODIC NONLINEARITY; QUANTUM-NOISE; LASER; SPECTROSCOPY; ERROR AB We demonstrate a new heterodyne Michelson interferometer design for displacement measurements capable of fringe interpolation accuracy of one part in 36 000. Key to this level of accuracy are the use of two acousto-optic modulators for heterodyne frequency generation and digital signal processing demodulation electronics. We make a direct comparison of our interferometer to a commercial interferometer based on a Zeeman-stabilized laser, and show that the residual periodic errors in ours are two orders of magnitude lower than those in the commercial unit. We discuss electronically induced optical cross talk and optical feedback as sources of periodic error. Our new interferometer is simple, robust, and readily implemented. [S0034-6748(00)05107-8]. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Lawall, J (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NR 20 TC 111 Z9 116 U1 4 U2 24 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD JUL PY 2000 VL 71 IS 7 BP 2669 EP 2676 DI 10.1063/1.1150715 PG 8 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 329KU UT WOS:000087906800008 ER PT J AU Buckley, TJ Hamelin, J Moldover, MR AF Buckley, TJ Hamelin, J Moldover, MR TI Toroidal cross capacitor for measuring the dielectric constant of gases SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article ID VIRIAL-COEFFICIENTS; TEMPERATURE; THERMOMETRY; PRESSURE AB We describe toroidal cross capacitors built to accurately measure the dielectric constant of gases. We tested the capacitors by measuring the dielectric polarizability of helium and argon at 7 and 50 degrees C at pressures up to 3 MPa. For helium, the results are consistent with the ab initio calculation of the molar polarizability and are limited by the uncertainties of the capacitance measurements. For argon, the results are consistent with the best previously published measurements of the polarizability and are limited by the uncertainties of the pressure measurements. Lessons learned are provided. [S0034-6748(00)02407-2]. C1 NIST, Phys & Chem Properties Div, Gaithersburg, MD 20899 USA. RP Moldover, MR (reprint author), NIST, Phys & Chem Properties Div, Gaithersburg, MD 20899 USA. RI Moldover, Michael/E-6384-2013 NR 27 TC 14 Z9 14 U1 0 U2 4 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD JUL PY 2000 VL 71 IS 7 BP 2914 EP 2921 DI 10.1063/1.1150716 PG 8 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 329KU UT WOS:000087906800047 ER PT J AU Conny, JM Powell, CJ AF Conny, JM Powell, CJ TI Standard test data for estimating peak parameter errors in x-ray photoelectron spectroscopy: II. Peak intensities SO SURFACE AND INTERFACE ANALYSIS LA English DT Article DE XPS; curve fitting; peak intensity; reference data; bias; accuracy; random error; precision; algorithm testing ID ELECTRON-SPECTROSCOPY; RANDOM UNCERTAINTIES; DATA SETS; AES; XPS; ENERGIES AB Standard test data for a-ray photoelectron spectroscopy (XPS-STD) hare been developed far determining bias and random error in peak parameters derived from curve fitting in XPS. The XPS-STD are simulated C Is spectra from spline polynomial models of measured C Is polymer spectra, Some have a single peak, but most are doublet spectra, The doublets were created from a factorial design with three factors: peak separation, relative intensity of the component peaks, and fractional Poisson noise. These doublet spectra simulated XPS measurements made on different two-component polymer specimens. This, the second of a three-part study, focuses on bias and random errors in determining peak intensities. We report the errors in results from 20 analysts who used a variety of programs and curve-fitting approaches. Peak intensities were analyzed as a ratio of the intensity of the larger peak in a doublet to the total intensity, or as a ratio of intensities for singlet peaks in separate but related spectra, For spectra that were correctly identified as doublets, bias and random errors in peak intensities depended on the amount of separation between the component peaks and on their relative intensities. Median biases for doublets calculated on a relative, unitless scale from -1 to 1 ranged from -0.33 to 0.17, whereas random errors for doublets calculated on the same scale ranged from 0.016 to 0.18, In most cases the magnitude of the median bias exceeded the median random error. On this scale, errors of -0.33 and 0.18 corresponded to errors of factors of 4 and 2, respectively, in determinations of the relative intensities as a ratio of the larger peak in a doublet to the smaller peak,. Analysts may evaluate uncertainties in their own analyses of the XPS-STD by visiting the web site http://www.acg.nist.gov/std/. Copyright (C) 2000 John Wiley & Sons, Ltd. C1 Natl Inst Stand & Technol, Surface & Microanal Sci Div, Gaithersburg, MD 20899 USA. RP Conny, JM (reprint author), Natl Inst Stand & Technol, Surface & Microanal Sci Div, Gaithersburg, MD 20899 USA. NR 27 TC 13 Z9 13 U1 1 U2 5 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 JUL PY 2000 VL 29 IS 7 BP 444 EP 459 DI 10.1002/1096-9918(200007)29:7<444::AID-SIA888>3.0.CO;2-M PG 16 WC Chemistry, Physical SC Chemistry GA 335BU UT WOS:000088222800004 ER PT J AU Pfeifer, L AF Pfeifer, L TI Winterbotham was right!! SO SURVEY REVIEW LA English DT Article AB Winterbotham was fully justified in his assumption that the Ordnance Survey standard bar OI2 has not changed its length between 1864 and 1906. That being the case, accurate metric equivalents of the dimensions of the Clarke 1858 ellipsoid (defined in feet of the Ordnance Survey standard bar O-1) and of the Clarke 1866 and 1880 ellipsoids (defined in feet of the Clarke Yard) may be accurately computed. C1 NOAA, Cheyenne, WY 82009 USA. NR 17 TC 3 Z9 3 U1 0 U2 0 PU COMMONWEALTH ASSOC SURVEYING LAND ECONOMY, C A S L E PI BRISTOL PA UNIV WEST ENGLAND, C/O FACULTY BUILT ENVIRONMENT, FRENCHAY CAMPUS, COLDHARBOUR L, BRISTOL BS16 1QY, ENGLAND SN 0039-6265 J9 SURV REV JI Surv. Rev. PD JUL PY 2000 VL 35 IS 277 BP 455 EP 463 PG 9 WC Engineering, Civil; Geosciences, Multidisciplinary; Remote Sensing SC Engineering; Geology; Remote Sensing GA 348QV UT WOS:000088998200002 ER PT J AU Begg, GA Brown, RW AF Begg, GA Brown, RW TI Stock identification of haddock Melanogrammus aeglefinus on Georges bank based on otolith shape analysis SO TRANSACTIONS OF THE AMERICAN FISHERIES SOCIETY LA English DT Article ID MORONE-SAXATILIS; ATLANTIC SALMON; STRIPED BASS; GROWTH; DISCRIMINATION; MORPHOLOGY; SALAR; SIZE AB Otolith shape analysis was examined to determine its utility for stock identification of haddock Melanogrammus aeglefinus on Georges Bank. Otolith samples were collected from the Northeast Peak (eastern Georges Bank) and the Great South Channel (western Georges Bank) spawning components to examine stock continuity across Georges Bank. Otolith shape was described using 20 Fourier harmonics, four morphometric characteristics (area, length, width, and perimeter), and two shape indices (circularity and rectangularity). Potential confounding sources of variation (fish length, otolith position, age-group, and year-class) were examined and accounted for in the analyses before interpretation of spatial/stock differences. Significant age-specific differences in otolith shape between eastern and western Georges Bank haddock indicated stock separation across the Bank. Classification success for each spawning component ranged from 63 to 80% across age-groups and appeared to depend on growth rate differences. Otolith shape analysis has potential for stock identification of haddock on Georges Bank, but only for year-classes with differing growth rates. The results of this study indicated an underlying stock structure within the Georges Bank transboundary haddock resource that may assist in defining consistent stock definitions used by the United States and Canada. 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,Skulagata 4, IS-121 Reykjavik, Iceland. NR 46 TC 70 Z9 83 U1 5 U2 18 PU AMER FISHERIES SOC PI BETHESDA PA 5410 GROSVENOR LANE SUITE 110, BETHESDA, MD 20814-2199 USA SN 0002-8487 J9 T AM FISH SOC JI Trans. Am. Fish. Soc. PD JUL PY 2000 VL 129 IS 4 BP 935 EP 945 DI 10.1577/1548-8659(2000)129<0935:SIOHMA>2.3.CO;2 PG 11 WC Fisheries SC Fisheries GA 342NW UT WOS:000088652700004 ER PT J AU Wertheimer, AC Heintz, RA Thedinga, JF Maselko, JM Rice, SD AF Wertheimer, AC Heintz, RA Thedinga, JF Maselko, JM Rice, SD TI Straying of adult pink salmon from their natal stream following embryonic exposure to weathered Exxon Valdez crude oil SO TRANSACTIONS OF THE AMERICAN FISHERIES SOCIETY LA English DT Article ID PRINCE-WILLIAM-SOUND; ALASKA; POPULATIONS AB Numbers of strays (adult salmon returning to a nonnatal stream:), straying rates, and distribution of strays were estimated for pink salmon incubated in oil-contaminated gravel and for an unexposed control group. The treatment groups were incubated in oiled gravel, which resulted in initial aqueous exposures for total polynuclear aromatic hydrocarbons (TPAHs) of 5 and 19 mu g/L for a low and high dose, respectively; the control group was incubated in gravel without oil. Fry from each treatment group were marked with coded wire tags (CWTs). The numbers of tagged fish released were 65,409 from the control; 69,441 from the low-dose group; and 70,414 from the high-dose group. A total of 288,492 pink salmon were sampled for CWTs when returning to spawn in the natal stream of the experimental fish, when returning to streams within 60 km of the natal stream, and when returning to two hatcheries within 100 km of the natal stream. The frequencies of observed strays were 0.023, 0.030, and 0.025 for the control, low-dose, and high-dose groups, respectively. Although the frequency of observed strays was 30% and 9% (respectively) higher than the controls for the low- and high-dose groups, the differences among treatments were not statistically significant, and the rates did not increase with TPAH dose. Estimates of the adult straying rates (with 95% confidence intervals) within a 35-km radius of the natal watershed were as follows: 5.3% (3.4-7.1%) for the control group; 9.2% (5.1-13.2%) for the low-dose group; and 5.7% (2.8-8.5%) for the high-dose group. Most (90%) strays were recovered within 10 km of the natal watershed. Exposed fish tended to be recovered at a greater distance from the natal stream than were control fish. The estimated percentage of strays recovered within 10 km was higher for the control group (95%) than for either the low-dose (81%) or high-dose (83%) groups, and only fish from oiled groups were recovered in distant fishing areas. However, these differences were also not statistically significant. Our results do not support the hypothesis that oil exposure of embryos in intertidal spawning grounds was responsible for the high rates of straying of wildstock pink salmon that were observed in Prince William Sound after the Exxon Valdez oil spill. C1 NOAA, Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr, Auke Bay Lab, Juneau, AK 99801 USA. RP Wertheimer, AC (reprint author), NOAA, Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr, Auke Bay Lab, 11305 Glacier Highway, Juneau, AK 99801 USA. NR 40 TC 10 Z9 11 U1 0 U2 10 PU AMER FISHERIES SOC PI BETHESDA PA 5410 GROSVENOR LANE SUITE 110, BETHESDA, MD 20814-2199 USA SN 0002-8487 J9 T AM FISH SOC JI Trans. Am. Fish. Soc. PD JUL PY 2000 VL 129 IS 4 BP 989 EP 1004 DI 10.1577/1548-8659(2000)129<0989:SOAPSF>2.3.CO;2 PG 16 WC Fisheries SC Fisheries GA 342NW UT WOS:000088652700008 ER PT J AU Brownell, RL Curry, BE Van Bonn, W Ridgway, SH AF Brownell, RL Curry, BE Van Bonn, W Ridgway, SH TI Conservation conundrum SO SCIENCE LA English DT Letter ID GENETIC DIVERSITY; POPULATIONS; DISEASE C1 SW Fisheries Sci Ctr, La Jolla, CA 92038 USA. USN, Marine Mammal Program, San Diego, CA 92152 USA. RP Brownell, RL (reprint author), SW Fisheries Sci Ctr, POB 271, La Jolla, CA 92038 USA. NR 11 TC 3 Z9 3 U1 0 U2 4 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD JUN 30 PY 2000 VL 288 IS 5475 BP 2319 EP 2320 PG 2 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 329NP UT WOS:000087913400019 PM 10917829 ER PT J AU Pierson, JM Kawa, SR Salawitch, RJ Hanisco, TF Lauzendorf, EJ Perkins, KK Gao, RS AF Pierson, JM Kawa, SR Salawitch, RJ Hanisco, TF Lauzendorf, EJ Perkins, KK Gao, RS TI Influence of air mass histories on radical species during the Photochemistry of Ozone Loss in the Arctic Region in Summer (POLARIS) mission SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID IN-SITU MEASUREMENTS; LOWER STRATOSPHERE; MIDDLE STRATOSPHERE; REACTIVE NITROGEN; CHLORINE RADICALS; AIRCRAFT; TRANSPORT; SPECTROMETER; TROPOSPHERE; SATELLITE AB The Goddard trajectory chemistry model was used with ER-2 aircraft data to test our current knowledge of radical photochemistry during the Photochemistry of Ozone Loss in the Arctic Region in Summer (POLARIS) campaign. The results of the trajectory chemistry model with and without trajectories are used to identify cases where steady state does not accurately describe the measurements. Over the entire mission, using trajectory chemistry reduces the variability in the modeled NOx comparisons to data by 25% with respect to the same model simulating steady state. Although the variability is reduced, NOx/NOy trajectory model results were found to be systematically low relative to the observations by 20-30% as seen in previous studies, Using new rate constants for reactions important in NOy partitioning improves the agreement of NOx/NOy with the observations but a 5-10% bias still exists. OH and HO2 individually are underpredicted by 15% of the standard steady state model and worsen with the new rate constants. Trajectory chemistry model results of OH/HO2 were systematically low by 10-20% but improve using the new rates constants because of the explicit dependence on NO. This suggests that our understanding of NOx is accurate to the 20% level and HOx chemistry is accurate to the 30% level in the lower stratosphere or better for the POLARIS regime. The behavior of the NOx and HOx comparisons to data using steady state versus trajectory chemistry and with updated rate coefficients is discussed in terms of known chemical mechanisms and lifetimes. C1 Univ Space Res Assoc, Seabrook, MD 20706 USA. NOAA, Aeron Lab, Colorado Springs, CO 80903 USA. Harvard Univ, Dept Chem, Cambridge, MA 02138 USA. NASA, Goddard Space Flight Ctr, Atmospher Chem & Dynam Branch, Greenbelt, MD 20771 USA. CALTECH, Jet Prop Lab, NASA, Pasadena, CA 91125 USA. RP Univ Space Res Assoc, Seabrook, MD 20706 USA. EM pierson@polska.gsfc.nasa.gov RI Salawitch, Ross/B-4605-2009; Kawa, Stephan/E-9040-2012; Gao, Ru-Shan/H-7455-2013 OI Salawitch, Ross/0000-0001-8597-5832; NR 45 TC 4 Z9 4 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 JUN 27 PY 2000 VL 105 IS D12 BP 15185 EP 15199 DI 10.1029/2000JD900111 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 328HP UT WOS:000087844900006 ER PT J AU Frisch, AS Martner, BE Djalalova, I Poellot, MR AF Frisch, AS Martner, BE Djalalova, I Poellot, MR TI Comparison of radar/radiometer retrievals of stratus cloud liquid-water content profiles with in situ measurements by aircraft SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID MICROWAVE RADIOMETER; RADAR; STRATOCUMULUS; PARAMETERS AB In situ sampling of cloud droplets by aircraft in Oklahoma in 1997 is used to evaluate a ground-based remote sensing technique for retrieving profiles of cloud liquid-water content. The technique uses vertically pointing measurements from a high-sensitivity millimeter-wavelength radar and a collocated dual-frequency microwave radiometer to obtain height-resolved estimates of the liquid content of stratiform clouds. Comparisons with the aircraft measurements are made for 16 overpasses through thin cloud layers within a 1.5-km radius of the remote sensor site. Over a range of liquid-water contents from 0.04 to 0.57 g m(-3) the mean difference between the aircraft and the radar/radiometer values was 0.02 g m(-3), and the maximum difference was 0.09 g m(-3). Although the number of comparisons is limited, these results suggest that the ground-based estimates may be sufficiently accurate for many scientific purposes. C1 Colorado State Univ, CIRA, Ft Collins, CO 80523 USA. NOAA, Environm Technol Lab, Boulder, CO 80303 USA. Sci Technol Corp, Boulder, CO 80303 USA. Univ N Dakota, Dept Atmospher Sci, Grand Forks, ND 58201 USA. RP Colorado State Univ, CIRA, Ft Collins, CO 80523 USA. EM sfrisch@etl.noaa.gov NR 13 TC 5 Z9 6 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 JUN 27 PY 2000 VL 105 IS D12 BP 15361 EP 15364 DI 10.1029/2000JD900128 PG 4 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 328HP UT WOS:000087844900017 ER PT J AU Finkelstein, PL Ellestad, TG Clarke, JF Meyers, TP Schwede, DB Hebert, EO Neal, JA AF Finkelstein, PL Ellestad, TG Clarke, JF Meyers, TP Schwede, DB Hebert, EO Neal, JA TI Ozone and sulfur dioxide dry deposition to forests: Observations and model evaluation SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID DECIDUOUS FOREST; ATMOSPHERIC DEPOSITION; NITROGEN-OXIDES; PINE FOREST; SPRUCE; O-3; VEGETATION; VELOCITIES; EXCHANGE; SURFACES AB Fluxes and deposition velocities of O-3 and SO2 were measured over both a deciduous and a mixed coniferous-deciduous forest for full growing seasons. Fluxes and deposition velocities of O-3 were measured over a coniferous forest for a month. Mean deposition velocities of 0.35 to 0.48 cm/s for O-3 and 0.6 to 0.72 cm/s for SO2 were observed during the growing seasons of 1997 and 1998. Weekly averages of O-3 deposition velocity ranged from 0.25 cm/s at the beginning and end of the season to 1.25 cm/s in late June. SO2 had a smaller seasonal variation, from 0.75 to 1.5 cm/s between the beginning and peak of the season. Because O-3 concentrations are higher, the flux of O-3 to forests is considerably greater than the flux of SO2. Daytime deposition velocities are very similar at each site, from 0.75 to 0.79 cm/s for O-3, and from 1.01 to 1.04 cm/s for SO2. Diurnal cycles for both gases are discussed, as are the impact of some weather events. The peak time for O-3 deposition velocity is in midmorning, while it is near midday for SO2. Surface wetness is usually associated with a small increase in deposition velocity, but for some rain events a major increase was noted. Minimum deposition velocities usually occur at night and increase slowly in the predawn hours before light. Comparisons are made between observations of deposition velocity and predictions made with the Meyers multilayer deposition velocity model. While the model is, on average, unbiased for O-3, it tends to underpredict the higher deposition velocity values. The model is slightly biased low (underpredicts) for SO2 deposition velocity. The strengths of the model are noted, as are opportunities for improvement. C1 US EPA, Natl Exposure Res Lab, Res Triangle Pk, NC 27711 USA. NOAA, Atmospher Sci Modeling Div, Air Resources Lab, Atmospher Turbulence & Diffus Div, Oak Ridge, TN 37830 USA. Environm Sci & Engn Inc, Gainesville, FL 32607 USA. RP US EPA, Natl Exposure Res Lab, MD-80, Res Triangle Pk, NC 27711 USA. EM finkelstein.peter@epamail.epa.gov RI Meyers, Tilden/C-6633-2016 NR 41 TC 64 Z9 66 U1 1 U2 10 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUN 27 PY 2000 VL 105 IS D12 BP 15365 EP 15377 DI 10.1029/2000JD900185 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 328HP UT WOS:000087844900018 ER PT J AU Randel, WJ Wu, F Gaffen, DJ AF Randel, WJ Wu, F Gaffen, DJ TI Interannual variability of the tropical tropopause derived from radiosonde data and NCEP reanalyses SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID QUASI-BIENNIAL OSCILLATION; STRATOSPHERIC WATER-VAPOR; SATELLITE DATA; ANNUAL CYCLE; EL CHICHON; GLOBAL QBO; TEMPERATURE; CIRCULATION; HEIGHT; PINATUBO AB Interannual variability of the tropical tropopause is studied using long time series of radiosonde data, together with global tropopause analyses from the National Centers for Environmental Prediction (NCEP) reanalyses over 1957-1997. Comparisons for the period 1979-1997 show the NCEP tropopause temperature is too warm by similar to 3-5 Ii and too high in pressure by similar to 2-6 mbar. However, these biases are approximately constant in time, so that seasonal and interannual variability is reasonably well captured by the NCEP data. Systematic differences in NCEP tropopause statistics are observed between the presatellite (1957-1978) and postsatellite (1979-1997) periods, precluding the use of the reanalyses for the study of multidecadal variability. Interannual anomalies in tropical average radiosonde and NCEP data show variations of order +/-1-2 Ii over the period 1979-1997, but there can be differences between these two estimates which are of similar magnitude. These differences impact estimates of decadal trends: During 1979-1997, negative trends in tropopause temperature of order -0.5 K/decade are observed in radiosonde data but are not found in NCEP reanalyses. The space-time patterns of several coherent signals are identified in both sets of tropopause statistics. The volcanic eruption of El Chichon (1982) warmed the tropical tropopause by similar to 1-2 ii and lowered its altitude by similar to 200 m for approximately 1-2 years. Smaller tropopause variations are observed following Mount Pinatubo (1991), particularly in radiosonde data. The signatures of the quasi biennial oscillation (QBO) and El-Nino/Southern Oscillation (ENSO) events are strong in tropopause statistics. QBO variations are primarily zonal mean in character, while ENSO events exhibit dipole patterns over Indonesia and the central Pacific Ocean, with small signals for zonal averages. C1 Natl Ctr Atmospher Res, Div Atmospher Chem, Boulder, CO 80307 USA. NOAA, Air Resources Lab, Silver Spring, MD 20910 USA. RP Natl Ctr Atmospher Res, Div Atmospher Chem, POB 3000, Boulder, CO 80307 USA. EM randel@ucar.edu RI Randel, William/K-3267-2016 OI Randel, William/0000-0002-5999-7162 NR 57 TC 178 Z9 192 U1 1 U2 22 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 JUN 27 PY 2000 VL 105 IS D12 BP 15509 EP 15523 DI 10.1029/2000JD900155 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 328HP UT WOS:000087844900027 ER PT J AU Barrett, TP Hegerl, G Knutson, T Tett, S AF Barrett, TP Hegerl, G Knutson, T Tett, S TI Uncertainty levels in predicted patterns of anthropogenic climate change SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID MODEL INTERCOMPARISON PROJECT; SURFACE-TEMPERATURE; GREENHOUSE-GAS; FINGERPRINT DETECTION; GLOBAL CLIMATE; VARIABILITY; SIGNALS; ATTRIBUTION; PACIFIC; DETECTABILITY AB This paper investigates the uncertainties in different model estimates of an expected anthropogenic signal in the near-surface air temperature field. We first consider nine coupled global climate models (CGCMs) forced by CO2 increasing at the rate of 1%/ pr. Averaged over years 71-SO of their integrations, the approximate time of CO2 doubling, the models produce a global mean temperature change that agrees to within about 25% of the nine model average. However, the spatial patterns of change can be rather different. This is likely to be due to different representations of various physical processes in the respective models, especially those associated with land and sea ice processes. We next analyzed 11 different runs from three different CGCMs, each forced by observed/projected greenhouse gases (GHG) and estimated direct sulfate aerosol effects. Concentrating on the patterns of trend of near-surface air temperature change over the period 1945-1995, we found that the raw individual model simulations often bore little resemblance to each other or to the observations. This was due partially to large magnitude, small-scale spatial noise that characterized all the model runs, a feature resulting mainly from internal model variability. Heavy spatial smoothing and ensemble averaging improved the intermodel agreement. The existence of substantial differences between different realizations of an ensemble produced by identical forcing almost requires that detection and attribution work be done with ensembles of scenario runs, as single runs can be misleading. Application of recent detection and attribution methods, coupled with ensemble averaging, produced a reasonably consistent match between model predictions of expected patterns of temperature trends due to a combination of GHG and direct sulfate aerosols and those observed. This statement is provisional since the runs studied here did not include other anthropogenic pollutants thought to be important (e.g., indirect sulfate aerosol effects, tropospheric ozone) nor do they include natural forcing mechanisms (volcanoes, solar variability). Our results demonstrate the need to use different estimates of the anthropogenic fingerprint in detection studies. Different models give different estimates of these fingerprints, and we do not currently know which is most correct. Further, the intramodel uncertainty in both the fingerprints and, particularly, the scenario runs can be relatively large. In short, simulation, detection, and attribution of an anthropogenic signal is a job requiring multiple inputs from a diverse set of climate models. C1 Scripps Inst Oceanog, La Jolla, CA 92037 USA. Texas A&M Univ, College Stn, TX 77843 USA. Geophys Fluid Dynam Lab, Princeton, NJ 08542 USA. Hadley Ctr Climate Predict & Res, Meteorol Off, Bracknell RG12 2SY, Berks, England. RP Scripps Inst Oceanog, MC 0224, La Jolla, CA 92037 USA. EM tbarnett@ucsd.edu RI Tett, Simon/B-1504-2013 OI Tett, Simon/0000-0001-7526-560X NR 49 TC 14 Z9 16 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 JUN 27 PY 2000 VL 105 IS D12 BP 15525 EP 15542 DI 10.1029/2000JD900162 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 328HP UT WOS:000087844900028 ER PT J AU Weickmann, KM Robinson, WA Penland, C AF Weickmann, KM Robinson, WA Penland, C TI Stochastic and oscillatory forcing of global atmospheric angular momentum SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID SEA-SURFACE TEMPERATURE; MADDEN-JULIAN OSCILLATION; TROPICAL CONVECTION; NORTHERN WINTER; PACIFIC-OCEAN; VARIABILITY; ANOMALIES; MODEL; LENGTH AB The temporal variability and forcing of global atmospheric angular momentum (AAM?) is studied using a three-component Markov model derived from observed statistics of global AAM and the global torques. The model consists of stochastic forcing by the mountain (tau(M)) and friction ( tau(F)*) torque plus a pervasive negative feedback on AAM by the friction torque. AAM anomalies are damped at a 30-day timescale and forced by torques having 1.5-day (tau(M)) and 6-day (tau(F)*) decorrelation timescales. A large portion of the intraseasonal variance and covariance of AAM, tau(M), and tau(F) is accounted for by the Markov model. Differences between the modeled and the observed covariances are maximized in the 10- to 90-day band and account for 10-30% of the variance when using data not stratified by season. An especially prominent deviation from the Markov model is the oscillatory forcing of AAM by the frictional torque at 30- to 60-day periods. Additionally, there is greater coherent variance between tau(F) and tau(M) across the entire 10-to 90-day band, with the frictional torque leading the mountain torque. This "feedback" between the global torques results from physical processes not represented in the Markov model. The synoptic characteristics of the stochastic mountain and frictional torques and of the oscillatory Madden-Julian Oscillation are described. C1 NOAA, CIRES Clim Diagnost Ctr, Boulder, CO 80303 USA. Univ Illinois, Dept Atmospher Sci, Urbana, IL 61801 USA. RP NOAA, CIRES Clim Diagnost Ctr, 325 Broadway, Boulder, CO 80303 USA. EM kmw@cdc.noaa.gov RI Robinson, Walter/I-3782-2012 OI Robinson, Walter/0000-0002-6669-7408 NR 28 TC 32 Z9 32 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 JUN 27 PY 2000 VL 105 IS D12 BP 15543 EP 15557 DI 10.1029/2000JD900198 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 328HP UT WOS:000087844900029 ER PT J AU Casassa, MP AF Casassa, MP TI Nanotechnology SO CHEMICAL & ENGINEERING NEWS LA English DT Letter C1 NIST, Program Off, Gaithersburg, MD 20899 USA. RP Casassa, MP (reprint author), NIST, Program Off, 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 0009-2347 J9 CHEM ENG NEWS JI Chem. Eng. News PD JUN 26 PY 2000 VL 78 IS 26 BP 8 EP 8 PG 1 WC Chemistry, Multidisciplinary; Engineering, Chemical SC Chemistry; Engineering GA 327XB UT WOS:000087818800004 ER PT J AU van der Zaag, PJ Ijiri, Y Borchers, JA Feiner, LF Wolf, RM Gaines, JM Erwin, RW Verheijen, MA AF van der Zaag, PJ Ijiri, Y Borchers, JA Feiner, LF Wolf, RM Gaines, JM Erwin, RW Verheijen, MA TI Difference between blocking and Neel temperatures in the exchange biased Fe3O4/CoO system SO PHYSICAL REVIEW LETTERS LA English DT Article ID ANTIFERROMAGNETIC LAYER THICKNESS; RANGE MAGNETIC ORDER; FILMS; DEPENDENCE; SUPERLATTICES; BILAYERS; ANISOTROPY; GROWTH; COO AB The blocking temperature T-B has been determined as a function of the antiferromagnetic layer thickness in the Fe3O4/CoO exchange biased system. For CoO layers thinner than 50 Angstrom, T-B is reduced below the Neel temperature T-N of bulk CoO (291 K), independent of crystallographic orientation or film substrate (alpha-Al2O3, SrTiO3, and MgO). Neutron diffraction studies show that T-B does not track the CoO ordering temperature and, hence, that this reduction in T-B does riot arise from finite-size scaling. Instead, the ordering temperature of the CoO layers is enhanced above the bulk T-N for layer thicknesses less than or similar to 100 Angstrom due to the proximity of magnetic Fe3O4 layers. C1 Philips Res Labs, NL-5656 AA Eindhoven, Netherlands. CFT, NL-5656 AA Eindhoven, Netherlands. Natl Inst Stand & Technol, NIST Ctr Neutron Res, Gaithersburg, MD 20899 USA. Oberlin Coll, Dept Phys, Oberlin, OH 44074 USA. RP van der Zaag, PJ (reprint author), Philips Res Labs, Cross Oak Lane, Redhill RH1 5HA, Surrey, England. RI van der Zaag, Pieter/F-7431-2014 OI van der Zaag, Pieter/0000-0001-9080-4907 NR 29 TC 167 Z9 167 U1 8 U2 50 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 JUN 26 PY 2000 VL 84 IS 26 BP 6102 EP 6105 DI 10.1103/PhysRevLett.84.6102 PG 4 WC Physics, Multidisciplinary SC Physics GA 329LY UT WOS:000087909500046 PM 10991134 ER PT J AU Lee, S Samuels, DA Hoobler, RJ Leone, SR AF Lee, S Samuels, DA Hoobler, RJ Leone, SR TI Direct measurements of rate coefficients for the reaction of ethynyl radical (C2H) with C2H2 at 90 and 120 K using a pulsed Laval nozzle apparatus SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article ID INTERSTELLAR TEMPERATURES; TITANS ATMOSPHERE; RATE CONSTANTS; PHOTOCHEMISTRY; SPECTROSCOPY; DEPENDENCE; KINETICS; CASSINI; SI(100); H-2 AB Rate coefficients for the reaction C2H + C2H2 --> C4H2 + H are measured at 90 and 120 K by using a new pulsed Laval nozzle apparatus equipped with laser ionization, time-of-flight mass spectrometric detection. The C2H radicals are generated by 193 nm laser photolysis of C2H2, and the reaction product, C4H2, is directly detected by single-photon ionization at 118 nm (10.5 eV). Rate coefficients of (2.7 +/- 0.5) x 10(-10) and (2.5 +/- 0.4) x 10(-10) cm(3) molecule(-1) s(-1) are obtained at 90 and 120 K, compared to the room temperature value of 1.3 x 10(-10) cm(3) molecule(-1) s(-1). The results show a significant negative temperature dependence of the reaction rate coefficient below room temperature. The implications for models of planetary atmospheres, such as for Titan, are discussed. C1 Natl Inst Stand & Technol, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. Univ Colorado, Dept Chem & Biochem, Boulder, CO 80309 USA. RP Lee, S (reprint author), Natl Inst Stand & Technol, Joint Inst Lab Astrophys, Campus Box 440, Boulder, CO 80309 USA. NR 24 TC 22 Z9 22 U1 1 U2 11 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD JUN 25 PY 2000 VL 105 IS E6 BP 15085 EP 15090 DI 10.1029/1999JE001187 PG 6 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 328MK UT WOS:000087854500006 ER PT J AU Bucher, CR Lehmann, KK Plusquellic, DF Fraser, GT AF Bucher, CR Lehmann, KK Plusquellic, DF Fraser, GT TI Doppler-free nonlinear absorption in ethylene by use of continuous-wave cavity ringdown spectroscopy SO APPLIED OPTICS LA English DT Article ID DOWN SPECTROSCOPY; OPTICAL BISTABILITY; DIODE-LASER; SPECTROMETER; BAND; LINES AB We report what we believe to be the first systematic study of Doppler-free, nonlinear absorption by use of cavity ringdown spectroscopy. We have developed a variant of cavity ringdown spectroscopy for the mid-infrared region between 9 and 11 mu m, exploiting the intracavity power buildup that is possible with continuous-wave lasers. The infrared source consists of a continuous-wave CO2 laser with 1-mW tunable infrared sidebands that couple into a high-finesse stable resonator. me tune the sideband frequencies to observe a saturated. Doppler-free Lamb dip in the v(7), 11(1,10) <-- 11(2,10) rovibrational transition of ethylene (C2H4). Power studies of the Lamb dip are presented to examine the intracavity effects of saturation on the Lamb-dip linewidth, the peak depth, and the broadband absorption. (C) 2000 Optical Society of America. OCIS codes: 230.5750, 300.6190, 300.6320, 300.6340, 300.6420, 300.6460. C1 Princeton Univ, Dept Chem, Princeton, NJ 08544 USA. Natl Inst Stand & Technol, Opt Technol Div, Gaithersburg, MD 20899 USA. RP Bucher, CR (reprint author), Max Planck Inst Quantum Opt, Max Planck Gesell, Laser Chem Div, Hans Kopfermann Str 1, D-85740 Garching, Germany. EM christine.bucher@mpq.mpg.de; lehmann@princeton.edu; dplus@nist.gov NR 37 TC 29 Z9 29 U1 0 U2 15 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1559-128X EI 2155-3165 J9 APPL OPTICS JI Appl. Optics PD JUN 20 PY 2000 VL 39 IS 18 BP 3154 EP 3164 DI 10.1364/AO.39.003154 PG 11 WC Optics SC Optics GA 325GV UT WOS:000087668600021 PM 18345246 ER PT J AU Griesmann, U Kling, R AF Griesmann, U Kling, R TI Interferometric measurement of resonance transition wavelengths in CIV, SiIV, AlIII, AlII, and SiII SO ASTROPHYSICAL JOURNAL LA English DT Article DE atomic data; methods : laboratory; techniques : spectroscopic ID SPACE-TIME VARIATION; VACUUM-ULTRAVIOLET; FE-I; C-IV; ATOMS; CONSTANTS; DISCHARGE; SPECTRUM AB We have made the first interferomeric measurements of the wavelengths of the important ultraviolet diagnostic lines in the spectra C Iv near 155 nm and Si Iv near 139 nm with a vacuum ultraviolet Fourier transform spectrometer and high-current discharge sources. The wavelength uncertainties were reduced by 1 order of magnitude for the C Iv lines and by 2 orders of magnitude for the Si Iv lines. Our measurements also provide accurate wavelengths for resonance transitions in Al III, Al II, and Si II. C1 NIST, Gaithersburg, MD 20899 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Griesmann, U (reprint author), NIST, Gaithersburg, MD 20899 USA. NR 21 TC 27 Z9 27 U1 0 U2 0 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 JUN 20 PY 2000 VL 536 IS 2 BP L113 EP L115 DI 10.1086/312741 PN 2 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 335ER UT WOS:000088231000014 ER PT J AU Shi, Y Wang, SL Schwarz, FP AF Shi, Y Wang, SL Schwarz, FP TI Intersubunit association induces unique allosteric dependence of the T127L CRP mutant on pH SO BIOCHEMISTRY LA English DT Article ID CAMP RECEPTOR PROTEIN; CYCLIC-NUCLEOTIDE BINDING; GENE ACTIVATOR PROTEIN; CAP-DNA COMPLEX; POSITION-127; TRANSITION; STABILITY; MUTATIONS; AMP AB The allosteric activation of the T127-->L mutant of 3',5'-cyclic adenosine monophosphate (cAMP) receptor protein (CRP) by cAMP changes from an exothermic, independent two-site binding mechanism at pH 7.0 to an endothermic, interacting two-site binding mechanism at pH 5.2, similar to that observed for CRP at pH 7.0 and 5.2. Since the T127-->L mutation at the subunit interface of The CRP dimer creates a more perfect leucine-zipper motif, it is believed to increase the intersubunit association and the stability of the CRP, as is observed by the higher thermal stability of the T127L mutant relative to that of CRP in differential scanning calorimetry (DSC) measurements. The DSC scans also exhibit a single thermal denaturation transition for CRP and a S128A mutant from pH 5.2 to 7.0, while the broader transition peak of the T127L mutant becomes resolvable into two transitions below pH less than or equal to 5.2. Circular dichroism measurements on T127L and CRP at pH 7.0 and 5.2 show changes in the tertiary structure of both proteins with the exception of the tertiary structure around the two tryptophan residues in the aminoterminal domain. Although gel electrophoresis of the proteolysis (pH 5.2) products of T127L, CRP, and their cAMP- and cGMP-ligated complexes shows the subunit band and an amino-terminal domain fragment band, the fully allosterically activated complexes of T127L and CRP show the amino-terminal domain fragment band but not the subunit band. The results are interpreted in terms of the allosteric activation of CRP by cAMP by a conformational change from an "open" to a "closed" form of CRP, which involves changes in the tertiary structure of the carboxyl-terminal domains that are partially induced by an increase in the intersubunit association in T127L. While T127L retains its intersubunit association from pH 5.2 to 7.0, changes occur in the carboxyl-terminal domain so that the endothermic, allosteric activation mechanism. of CRP by cAMP is restored in T127L at pH 5.2. C1 Natl Inst Stand & Technol, Ctr Adv Res Biotechnol, Rockville, MD 20850 USA. RP Schwarz, FP (reprint author), Natl Inst Stand & Technol, Ctr Adv Res Biotechnol, 9600 Gudelsky Dr, Rockville, MD 20850 USA. NR 22 TC 8 Z9 8 U1 0 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0006-2960 J9 BIOCHEMISTRY-US JI Biochemistry PD JUN 20 PY 2000 VL 39 IS 24 BP 7300 EP 7308 DI 10.1021/bi000225m PG 9 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 327DQ UT WOS:000087778300031 PM 10852730 ER PT J AU Abusaidi, R Akerib, DS Barnes, PD Bauer, DA Bolozdynya, A Brink, PL Bunker, R Cabrera, B Caldwell, DO Castle, JP Clarke, RM Colling, P Crisler, MB Cummings, A Silva, AD Davies, AK Dixon, R Dougherty, BL Driscoll, D Eichblatt, S Emes, J Gaitskell, RJ Golwala, SR Hale, D Haller, EE Hellmig, J Huber, ME Irwin, KD Jochum, J Lipschultz, FP Lu, A Mandic, V Martinis, JM Nam, SW Nelson, H Neuhauser, B Penn, MJ Perera, TA Isaac, MCP Pritychenko, B Ross, RR Saab, T Sadoulet, B Schnee, RW Seitz, DN Shestople, P Shutt, T Smith, A Smith, GW Sonnenschein, AH Spadafora, AL Stockwell, W Taylor, JD White, S AF Abusaidi, R Akerib, DS Barnes, PD Bauer, DA Bolozdynya, A Brink, PL Bunker, R Cabrera, B Caldwell, DO Castle, JP Clarke, RM Colling, P Crisler, MB Cummings, A Silva, AD Davies, AK Dixon, R Dougherty, BL Driscoll, D Eichblatt, S Emes, J Gaitskell, RJ Golwala, SR Hale, D Haller, EE Hellmig, J Huber, ME Irwin, KD Jochum, J Lipschultz, FP Lu, A Mandic, V Martinis, JM Nam, SW Nelson, H Neuhauser, B Penn, MJ Perera, TA Isaac, MCP Pritychenko, B Ross, RR Saab, T Sadoulet, B Schnee, RW Seitz, DN Shestople, P Shutt, T Smith, A Smith, GW Sonnenschein, AH Spadafora, AL Stockwell, W Taylor, JD White, S CA CDMS Collaboration TI Exclusion limits on the WIMP-nucleon cross section from the Cryogenic Dark Matter Search SO PHYSICAL REVIEW LETTERS LA English DT Article ID 25 MK; IONIZATION; GERMANIUM; CRYSTAL AB Cryogenic Dark Matter Search (CDMS) employs Ge and Si detectors to search for weakly interacting massive particles (WIMPs) via their elastic-scattering interactions with nuclei while discriminating against interactions of background particles. CDMS data, accounting for the neutron background, give limits on the spin-independent WIMP-nucleon elastic-scattering cross section that exclude unexplored parameter space above 10 GeV/c(2) WIMP mass and, at >75% C.L., the entire 3 sigma allowed region for the WIMP signal reported by the DAMA experiment. C1 Univ Calif Berkeley, Ctr Particle Astrophys, Berkeley, CA 94720 USA. Case Western Reserve Univ, Dept Phys, Cleveland, OH 44106 USA. Fermi Natl Accelerator Lab, Batavia, IL 60510 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Natl Inst Stand & Technol, Boulder, CO 80303 USA. Princeton Univ, Dept Phys, Princeton, NJ 08544 USA. Santa Clara Univ, Dept Phys, Santa Clara, CA 95053 USA. San Francisco State Univ, Dept Phys & Astron, San Francisco, CA 94132 USA. Stanford Univ, Dept Phys, Stanford, CA 94305 USA. Univ Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93106 USA. Univ Colorado, Dept Phys, Denver, CO 80217 USA. RP Golwala, SR (reprint author), Univ Calif Berkeley, Ctr Particle Astrophys, Berkeley, CA 94720 USA. RI Huber, Martin/B-3354-2011 NR 33 TC 214 Z9 214 U1 0 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 JUN 19 PY 2000 VL 84 IS 25 BP 5699 EP 5703 DI 10.1103/PhysRevLett.84.5699 PG 5 WC Physics, Multidisciplinary SC Physics GA 325AC UT WOS:000087653300005 PM 10991035 ER PT J AU Jodwalis, CM Benner, RL Eslinger, DL AF Jodwalis, CM Benner, RL Eslinger, DL TI Modeling of dimethyl sulfide ocean mixing, biological production, and sea-to-air flux for high latitudes SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID SUBSTRATE CONCENTRATION; MICROBIAL CONSUMPTION; MARINE-PHYTOPLANKTON; ESTUARINE WATERS; DISSOLVED DMSP; SULFUR CYCLE; NORTH-SEA; ATMOSPHERE; PHAEOCYSTIS; BLOOM AB To explore the extent to which ocean mixed-layer dynamics influences dimethyl sulfide (DMS) sea-to-air flux at high latitudes, a model of DMS ocean mixing, biological production, and sea-to-air flux was developed. This biophysical one-dimensional model is driven by meteorology. The model simulates DMS seawater concentrations and vertical distributions, and DMS sea-to-air flux for Prince William Sound and the Gulf of Alaska, from early March through December, Sensitivity analyses revealed that DMS sea-to-air flux is most affected by the rates of flagellate production, zooplankton grazing, photooxidation, and microbial consumption of DMS. Model results show that under conditions of substantial vertical mixing, such as high wind stress or convective mixing, DMS sea-to-air flux increases significantly. At high latitudes these events may coincide with wind-driven mixing or the overturning of surface seawater due to decreasing sea surface temperatures in the autumn. Parameterizations used to estimate emissions of such a highly variable gas as dimethyl sulfide need to include ocean mixed-layer dynamics. The current model is limited by the small number of DMS loss and production rate measurements available, The measurements that do exist have large ranges and come almost exclusively from low and midlatitude regions, mostly during the summer months under calm conditions. Field measurements are needed from high-latitude systems to refine this model, making it an effective tool for designing field campaigns, improving the accuracy of DMS sea-to-air flux estimations, and assessing the contribution of northern oceans to the atmospheric sulfur budget. C1 Univ Alaska Fairbanks, Int Arct Res Ctr, Fairbanks, AK 99775 USA. NOAA, Coastal Serv Ctr, Coastal Remote Sensing Program, Charleston, SC 29405 USA. Univ Alaska Fairbanks, Dept Chem & Biochem, Fairbanks, AK 99775 USA. RP Jodwalis, CM (reprint author), Univ Alaska Fairbanks, Int Arct Res Ctr, Fairbanks, AK 99775 USA. EM ffcmj@uaf.edu NR 69 TC 14 Z9 15 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUN 16 PY 2000 VL 105 IS D11 BP 14387 EP 14399 DI 10.1029/2000JD900023 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 326LB UT WOS:000087736000004 ER PT J AU Newchurch, MJ Bishop, L Cunnold, D Flynn, LE Godin, S Frith, SH Hood, L Miller, AJ Oltmans, S Randel, W Reinsel, G Stolarski, R Wang, R Yang, ES Zawodny, JM AF Newchurch, MJ Bishop, L Cunnold, D Flynn, LE Godin, S Frith, SH Hood, L Miller, AJ Oltmans, S Randel, W Reinsel, G Stolarski, R Wang, R Yang, ES Zawodny, JM TI Upper-stratospheric ozone trends 1979-1998 SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID VERTICAL-DISTRIBUTION; NIMBUS-7 SBUV; UMKEHR; PROFILES; AEROSOL; DEPENDENCE; ATMOSPHERE; CHEMISTRY; MODEL; SAGE AB Extensive analyses of ozone observations between 1978 and 1998 measured by Dobson Umkehr, Stratospheric Aerosol and Gas Experiment (SAGE)I and II, and Solar Backscattered Ultraviolet (SBUV) and (SBUV)/2 indicate continued significant ozone decline throughout the extratropical upper stratosphere from 30-45 km altitude. The maximum annual linear decline of -0.8+/-0.2 % yr(-1)(2 sigma) occurs at 40 km and is well described in terms of a linear decline modulated by the 11-year solar variation. The minimum decline of -0.1+/-0.1% yr(-1)(2 sigma) occurs at 25 km in midlatitudes, with remarkable symmetry between the Northern and Southern Hemispheres at 40 km altitude. Midlatitude upper-stratospheric zonal trends exhibit significant seasonal variation (+/-30% in the Northern Hemisphere, +/-40% in the Southern Hemisphere) with the most negative trends of -1.2% yr(-1) occurring in the winter. Significant seasonal trends of -0.7 to -0.9% yr(-1) occur at 40 km in the tropics between April and September. Subjecting the statistical models used to calculate the ozone trends to intercomparison tests on a variety of common data sets yields results that indicate the standard deviation between trends estimated by 10 different statistical models is less than 0.1% yr(-1) in the annual-mean trend for SAGE data and less than 0.2% yr(-1) in the most demanding conditions (seasons with irregular, sparse data) [World Meteorological Organization (WMO), 1998]. These consistent trend results between statistical models together with extensive consistency between the independent measurement-system trend observations by Dobson Umkehr, SAGE I and TI, and SBUV and SBUV/2 provide a high degree of confidence in the accuracy of the declining ozone amounts reported here. Additional details of ozone trend results from 1978 to 1996 (2 years shorter than reported here) along with lower-stratospheric and tropospheric ozone trends, extensive intercomparisons to assess relative instrument drifts, and retrieval algorithm details are given by WMO [1998]. C1 Univ Alabama, Dept Atmospher Sci, Huntsville, AL 35899 USA. Natl Ctr Atmospher Res, Boulder, CO 80307 USA. Allied Signal Corp, Buffalo, NY 14210 USA. Georgia Inst Technol, Sch Earth & Atmospher Sci, Atlanta, GA 30332 USA. NOAA, Natl Environm Satellite Data & Informat Serv, Washington, DC 20233 USA. Univ Paris 06, Serv Aeron, F-75252 Paris, France. NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. NOAA, Natl Weather Serv, Climate Predict Ctr, Washington, DC 20233 USA. NOAA, Climate Monitoring & Diagnost Lab, Boulder, CO 80303 USA. Univ Wisconsin, Dept Stat, Madison, WI 53706 USA. NASA, Langley Res Ctr, Hampton, VA 23665 USA. RP Newchurch, MJ (reprint author), Univ Alabama, Dept Atmospher Sci, Huntsville, AL 35899 USA. EM mike@atmos.uah.edu; lane.bishop@alliedsignal.com; cunnold@eas.gatech.edu; lflynn@orbit.nesdis.noaa.gov; sophie.godin@aero.jussieu.fr; lon@lpl.arizona.edu; miller@upair.wwb.noaa.gov; soltmans@cmdl.noaa.gov; randel@ncar.ucar.edu; reinsel@stat.wisc.edu; stolarski@polska.gsfc.nasa.gov; yes@atmos.uah.edu RI Flynn, Lawrence/B-6321-2009; Stolarski, Richard/B-8499-2013; Randel, William/K-3267-2016 OI Flynn, Lawrence/0000-0001-6856-2614; Stolarski, Richard/0000-0001-8722-4012; Randel, William/0000-0002-5999-7162 NR 36 TC 35 Z9 35 U1 1 U2 6 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUN 16 PY 2000 VL 105 IS D11 BP 14625 EP 14636 DI 10.1029/2000JD900037 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 326LB UT WOS:000087736000022 ER PT J AU Petropavlovskikh, I Loughman, R DeLuisi, J Herman, B AF Petropavlovskikh, I Loughman, R DeLuisi, J Herman, B TI A comparison of UV intensities calculated by spherical-atmosphere radiation transfer codes: Application to the aerosol corrections SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID STRATOSPHERIC AEROSOL; OZONE PROFILES; RETRIEVAL; AUREOLE AB Various spherical radiative transfer (SRT) computer codes that model ultraviolet (UV) sky intensities incident at the Earth's surface are compared for clear-sky (Rayleigh scattering and ozone absorption) and hazy-sky (stratospheric volcanic aerosol, Rayleigh scattering, and ozone absorption) atmospheric conditions. Calculated sky intensities using Dave vector (pseudospherical), Dave scalar (pseudospherical), Herman's vector (full spherical), and Herman's scalar (full spherical) codes are compared for various parameters including solar zenith angle, direction of view, and wavelength. The differences in the calculated downward UV intensities are believed to arise from the differences in the code geometries and the neglect of polarization effects. The difference between downward UV intensities is within +/-15% for clear-sky conditions and between -30 and 18% for hazy-sky conditions. The results of comparisons suggest that an experiment should be conducted to measure UV sky intensities for clear-sky conditions, with minimal aerosol, to test the quality of the radiative transfer codes with actual observations. The Dave scalar radiative transfer code has been used in the past to calculate aerosol error corrections to Umkehr measurements. To evaluate the accuracy of these calculations, we performed a set of comparisons with results of various spherical radiative transfer codes. Ground level sky intensities were calculated for various solar zenith angle directions, for a vertically inhomogeneous Rayleigh atmosphere with ozone absorption, including and excluding stratospheric aerosols. For 0.11 stratospheric aerosol optical thickness, the method for calculating stratospheric aerosol errors to retrieved Umkehr ozone profile predicts either -22% or -32% error in layer 8 depending on whether vector or a scalar radiative transfer code had been used. The calculations were also used to study the effect of full spherical and pseudospherical forward model differences on Umkehr ozone profile retrievals. The difference in retrieved ozone profiles was found to be within +/-4% for clear-sky conditions and up to 13% in layer 8 for hazy-sky conditions. The results of these comparisons suggest that further improvements to the profile retrieval and stratospheric aerosol error calculations could he made using a fully spherical RT code that accounts for polarization. C1 NOAA, ERL, ARL, SRRB, Boulder, CO 80303 USA. Univ Arizona, Cooperat Ctr Atmospher Sci & Technol, Tucson, AZ 85721 USA. Univ Arizona, Inst Atmospher Phys, Tucson, AZ 85721 USA. Univ Colorado, CIRES, Boulder, CO 80309 USA. RP Petropavlovskikh, I (reprint author), NOAA, REARXL, 325 Broadway, Boulder, CO 80027 USA. EM irina@srrb.noaa.gov; loughman@wrabbit.gsfc.nasa.gov; deluisi@srrb.noaa.gov; herman@atmo.arizona.edu NR 25 TC 3 Z9 3 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUN 16 PY 2000 VL 105 IS D11 BP 14737 EP 14746 DI 10.1029/2000JD900136 PG 10 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 326LB UT WOS:000087736000029 ER PT J AU Rosenfeld, S Grody, N AF Rosenfeld, S Grody, N TI Anomalous microwave spectra of snow cover observed from Special Sensor Microwave/Imager measurements SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID SSM/I MEASUREMENTS AB Brightness temperature spectra measured by the Spacial Sensor Microwave/Imager (SSM/I) flown onboard F8 and F14 satellites of the U.S. Defense Meteorological Satellite Program (DMSP) during the 1987-1988 and 1997-1998 winter periods are analyzed concurrently with the data from snow monitoring stations over the former Soviet Union. Extensive analysis reveals the existence of two anomalies in the microwave thermal radiation spectra of snow cover. It is shown that in the beginning of winter the SSM/I measurements at 19, 37, and 85 GHz generally follow a classical pattern; that is, the brightness temperatures decrease for both increasing snow depth and increasing frequency. Dramatic departures fi um this behavior is observed around the middle of winter: The brightness temperatures roach a minimum and then begin to increase despite the fact that the snow depth remains constant or even continues to grow. Statistical analysis of the snow pack characteristics and SSM/I measurements is presented around the time when the brightness temperatures reach a minimum. The anomalous spectral characteristics are analyzed using a two-stream radiative transfer model and dense media theory. It is shown how metamorphic changes in the snow crystalline structure are responsible for the brightness temperature minimum. The second departure from the normal snow signature is the inversion of brightness temperature spectra; that is, the higher-frequency brightness temperature is greater than the low-frequency measurements. It is shown that tills phenomenon, observed previously over Greenland and Antarctica, is much more extensive. Radiative transfer simulations were used to show that a dense layer of surface crust on top of old coarse-grained snow can produce the invented brightness temperature spectrum. C1 Natl Environm Satellite Data & Informat Serv, NOAA, Camp Springs, MD 20746 USA. RP Rosenfeld, S (reprint author), Natl Environm Satellite Data & Informat Serv, NOAA, World Weather Bldg,Room 601,5200 Auth Rd, Camp Springs, MD 20746 USA. EM srosenfeld@nesdis.noaa.gov NR 24 TC 27 Z9 28 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUN 16 PY 2000 VL 105 IS D11 BP 14913 EP 14925 DI 10.1029/1999JD900486 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 326LB UT WOS:000087736000041 ER PT J AU Bernardet, LR Grasso, LD Nachamkin, JE Finley, CA Cotton, WR AF Bernardet, LR Grasso, LD Nachamkin, JE Finley, CA Cotton, WR TI Simulating convective events using a high-resolution mesoscale model SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID NUMERICAL WEATHER PREDICTION; UNITED-STATES; SYSTEMS; ENVIRONMENTS; DRYLINE; LAND; RAMS AB Four multiscale numerical simulations of convective events are analyzed to determine the essential characteristics of a numerical model which lead to useful simulations of convective events. Although several universities and weather forecasting centers are currently running high-resolution forecast models, the predictability of convective events, especially in the warm season, is still an issue among researchers and forecasters in the meteorological community. This study shows that explicit simulations of convection depend on the high spatial resolution of physiography (particularly topography and top soil moisture), efficient communication between grids of different scales, and initialization procedures that incorporate mesoscale storm features. C1 Colorado State Univ, Cooperat Inst Res Atmosphere, Ft Collins, CO 80521 USA. USN, Res Lab, Monterey, CA 93943 USA. Univ No Colorado, Dept Earth Sci, Greeley, CO 80639 USA. Colorado State Univ, Dept Atmospher Sci, Ft Collins, CO 80521 USA. NOAA, Forecast Syst Lab, Boulder, CO USA. CNR, Washington, DC 20418 USA. RP Bernardet, LR (reprint author), Inst Nacl Meteorol, SHIN Q13 Cj9 Cs9, BR-71505290 Brasilia, DF, Brazil. EM lrbernar@inmet.gov.br RI Bernardet, Ligia/N-3357-2014 NR 47 TC 32 Z9 34 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUN 16 PY 2000 VL 105 IS D11 BP 14963 EP 14982 DI 10.1029/2000JD900100 PG 20 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 326LB UT WOS:000087736000044 ER PT J AU Baughman, RH Dantas, SO Stafstrom, S Zakhidov, AA Mitchell, TB Dubin, DHE AF Baughman, RH Dantas, SO Stafstrom, S Zakhidov, AA Mitchell, TB Dubin, DHE TI Negative Poisson's ratios for extreme states of matter SO SCIENCE LA English DT Article ID CRYSTALLIZED ION PLASMAS; COLLOIDAL CRYSTALS; PHASE-DIAGRAMS; DUSTY PLASMAS; SUSPENSIONS; DIFFRACTION; SYSTEMS AB Negative Poisson's ratios are predicted for body-centered-cubic phases that Likely exist in white dwarf cores and neutron star outer crusts, as well as those found for vacuumlike ion crystals, plasma dust crystals, and colloidal crystals (including certain virus crystals). The existence of this counterintuitive property, which means that a material laterally expands when stretched, is experimentally demonstrated for very low density crystals of trapped ions. At very high densities, the large predicted negative and positive Poisson's ratios might be important for understanding the asteroseismology of neutron stars and white dwarfs and the effect of stellar stresses on nuclear reaction rates. Giant Poisson's ratios are both predicted and observed for highly strained coulombic photonic crystals, suggesting possible applications of large, tunable Poisson's ratios for photonic crystal devices. C1 Honeywell Int, Honeywell Technol Ctr, Morristown, NJ 07962 USA. Univ Fed Juiz de Fora, Dept Fis, BR-36036330 Juiz De Fora, MG, Brazil. Linkoping Univ, Dept Phys & Measurement Technol, S-58183 Linkoping, Sweden. Natl Inst Stand & Technol, Boulder, CO 80303 USA. Univ Calif San Diego, Dept Phys, La Jolla, CA 92093 USA. RP Baughman, RH (reprint author), Honeywell Int, Honeywell Technol Ctr, Morristown, NJ 07962 USA. RI Stafstrom, Sven/G-2982-2011; OI Stafstrom, Sven/0000-0001-6555-239X; Zakhidov, Anvar/0000-0003-3983-2229 NR 36 TC 52 Z9 54 U1 5 U2 26 PU AMER ASSOC ADVANCEMENT SCIENCE PI WASHINGTON PA 1200 NEW YORK AVE, NW, WASHINGTON, DC 20005 USA SN 0036-8075 J9 SCIENCE JI Science PD JUN 16 PY 2000 VL 288 IS 5473 BP 2018 EP + DI 10.1126/science.288.5473.2018 PG 6 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 325QC UT WOS:000087687000042 ER PT J AU De Gouw, JA Howard, CJ Custer, TG Baker, BM Fall, R AF De Gouw, JA Howard, CJ Custer, TG Baker, BM Fall, R TI Proton-transfer chemical-ionization mass spectrometry allows real-time analysis of volatile organic compounds released from cutting and drying of crops SO ENVIRONMENTAL SCIENCE & TECHNOLOGY LA English DT Article ID GAS-PHASE; OXYGENATED HYDROCARBONS; EMISSIONS; ISOPRENE; AIR; AEROSOLS; METHANOL; KETONES; FLUXES; LEAVES AB The wounding and drying of plant material during crop harvest could be a significant source of volatile organic compounds (VOCs) that enter the atmosphere. Here, we show that these primarily oxygenated VOCs can be measured using proton-transfer chemical-ionization mass spectrometry (PT-CIMS), a method that allows online and simultaneous monitoring of oxygenated VOC levels. For clover, alfalfa, and corn, leaf wounding and in particular drying were shown to lead to strongly enhanced emissions of a series of Cs aldehydes, alcohols, and esters derived from (Z)-3-hexenal. Additionally, for the forage crops clover and alfalfa, enhanced emissions of methanol, acetaldehyde, acetone, and butanone were observed. The identities of the measured carbonyl compounds were confirmed using high-pressure liquid chromatography. For clover, initial cutting led to a VOC release of about 175 mu g of C (g dry wt)(-1), while during drying the cut clover released >1000 mu g of C (g dry wt)(-1); qualitatively, similar amounts of VOCs were released from alfalfa, the major hay crop in the United States. The atmospheric implications of these findings may include effects on the local air quality in agricultural areas, contributions to long-range transport of pollutants, and effects on the formation of HOx (=OH + HO2) radicals in the upper troposphere. C1 NOAA, Environm Res Labs, Aeron Lab, Boulder, CO 80303 USA. Univ Colorado, Dept Chem & Biochem, Boulder, CO 80309 USA. Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. RP De Gouw, JA (reprint author), Univ Utrecht, Inst Marine & Atmospher Res, Princetonplein 5, NL-3584 CC Utrecht, Netherlands. RI de Gouw, Joost/A-9675-2008 OI de Gouw, Joost/0000-0002-0385-1826 NR 36 TC 70 Z9 71 U1 4 U2 18 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0013-936X J9 ENVIRON SCI TECHNOL JI Environ. Sci. Technol. PD JUN 15 PY 2000 VL 34 IS 12 BP 2640 EP 2648 DI 10.1021/es991219k PG 9 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA 325MA UT WOS:000087678300042 ER PT J AU Leibrock, E Huey, LG AF Leibrock, E Huey, LG TI Ion chemistry for the detection of isoprene and other volatile organic compounds in ambient air SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID ATMOSPHERIC TRACE GASES; MASS-SPECTROMETRY; TROPOSPHERE; STRATOSPHERE; HNO3 AB A chemical ionization mass spectrometer (CIMS) and a flowing afterglow apparatus were used to study reactions of benzene cations (C6H6+) and (C6H6)(2)(+)) with a series of volatile organic compounds (VOCs). Both cations read at the collision rate with compounds of lower ionization potential than benzene, such as isoprene (C5H8), other conjugated dienes, and aromatics. These ions are generally unreactive with substances of higher ionization potential such as alkanes, simple alcohols, simple carbonyls, etc. The results demonstrate that C6H6+ and (C6H6)(2)(+) are excellent reagent ions for the sensitive detection of isoprene in air with a CIMS. However, 2-methyl-3-buten-2-ol (MBO) and C5H8 conjugated dienes were identified as potential interferences to this technique. This indicates that the selectivity of the CIMS isoprene measurement must be tested by intercomparison with well-established methods, e.g. gas chromatography techniques. C1 NOAA, Aeron Lab, Environm Res Labs, Boulder, CO 80303 USA. Georgia Inst Technol, Sch Earth & Atmospher Sci, Atlanta, GA 30332 USA. Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. RP Leibrock, E (reprint author), NOAA, Aeron Lab, Environm Res Labs, 325 Broadway,R-E-AL7, Boulder, CO 80303 USA. NR 17 TC 12 Z9 12 U1 2 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 JUN 15 PY 2000 VL 27 IS 12 BP 1719 EP 1722 DI 10.1029/1999GL010804 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 325CD UT WOS:000087658000010 ER PT J AU Loukos, H Vivier, F Murphy, PP Harrison, DE Le Quere, C AF Loukos, H Vivier, F Murphy, PP Harrison, DE Le Quere, C TI Interannual variability of equatorial Pacific CO2 fluxes estimated from temperature and salinity data SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID ATMOSPHERIC CARBON-DIOXIDE; SEA-SURFACE TEMPERATURE; EL-NINO; WATERS; OCEAN AB Based on atmospheric data and models, the tropical CO2 source anomaly reaches up to 2 Gte yr(-1) but the respective contributions of the terrestrial biosphere and the oceans to this flux are difficult to quantify. Here we present a new method for estimating CO2 fluxes from oceanic observations based on the surprisingly good predictive skill of temperature and salinity for surface dissolved inorganic carbon. Using historical temperature and salinity data, we reconstruct the basin scale CO2 flux to the atmosphere in the equatorial Pacific from 1982 to 1993. We find that interannual anomalies do not exceed 0.4 +/-0.2 GtC yr(-1) which suggests that up to 80% of the tropical CO2 source anomaly is due to the terrestrial biosphere. C1 Inst Pierre Simon, Lab Oceanog Dynam & Climatol, F-75252 Paris 05, France. Univ Washington, Appl Phys Lab, Seattle, WA 98105 USA. NOAA, Natl Oceanog Data Ctr, Silver Spring, MD 20910 USA. NOAA, Pacific Marine Environm Lab, Seattle, WA 98115 USA. CEA Saclay, Inst Pierre Simon Laplace, Lab Sci Climat & Environm, F-91191 Gif Sur Yvette, France. RP Loukos, H (reprint author), Inst Pierre Simon, Lab Oceanog Dynam & Climatol, UPMC Boite 100,4 Pl Jussieu, F-75252 Paris 05, France. EM loukos@ipsl.jussieu.fr; fvi@apl.washington.edu; pmurphy@nodc.noaa.gov; harrison@pmel.noaa.gov; lequere@lsce.saclay.cea.fr RI Harrison, Don/D-9582-2013; Le Quere, Corinne/C-2631-2017 OI Le Quere, Corinne/0000-0003-2319-0452 NR 23 TC 18 Z9 21 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 JUN 15 PY 2000 VL 27 IS 12 BP 1735 EP 1738 DI 10.1029/1999GL011013 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 325CD UT WOS:000087658000014 ER PT J AU Williams, CR Kruger, A Gage, KS Tokay, A Cifelli, R Krajewski, WF Kummerow, C AF Williams, CR Kruger, A Gage, KS Tokay, A Cifelli, R Krajewski, WF Kummerow, C TI Comparison of simultaneous rain drop size distributions estimated from two surface disdrometers and a UHF profiles SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID SPECTRA; RADAR AB In support of the NASA Tropical Rainfall Measuring Mission (TRMM) Ground Validation Program, a suite of surface instruments and vertical pointing Doppler radar profilers were deployed in central Florida to quantify the number and size of the rain drops reaching the surface. Analyzing 276 minutes of simultaneous observations from two surface disdrometers and one profiler revealed good agreement among the instruments for drop sizes > 1.5 mm diameter but poor agreement for smaller drop sizes. The magnitude of the difference in small drop estimation was proportional to the reflectivity (and rainrate). At reflectivities greater than 40 dBZ, the differences in the estimation of the number of small drops yielded differences in estimates of mass-weighted diameter of > 13% and of rainrate > 25%. The combined effect of these uncertainties impact the interpretation of the precipitation processes and the development and validation of space-based precipitation retrieval algorithms. C1 NOAA, Aeron Lab, Boulder, CO 80303 USA. Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. Univ Iowa, Iowa Inst Hydraul Res, Iowa City, IA 52242 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Maryland Baltimore Cty, Joint Ctr Earth Syst Technol, Baltimore, MD 21228 USA. Colorado State Univ, Dept Atmospher Sci, Ft Collins, CO 80523 USA. RP Williams, CR (reprint author), NOAA, Aeron Lab, 325 Broadway,MS R-AL3, Boulder, CO 80303 USA. RI Williams, Christopher/A-2723-2015 OI Williams, Christopher/0000-0001-9394-8850 NR 17 TC 38 Z9 38 U1 1 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUN 15 PY 2000 VL 27 IS 12 BP 1763 EP 1766 DI 10.1029/1999GL011100 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 325CD UT WOS:000087658000021 ER PT J AU Zimmerman, NM Keller, MW AF Zimmerman, NM Keller, MW TI Dynamic input capacitance of single-electron transistors and the effect on charge-sensitive electrometers SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID COUNTING ELECTRONS AB We examine the "input capacitance," C-SETT, of a single-electron tunneling (SET) transistor. We note that this quantity is crucial in quantifying the sensitivity of a SET transistor used as a charge electrometer. Further, we point out that C-SETT is not the same as the "gate capacitance," C-G, usually taken to be e/Delta V-G, where Delta V-G is the period of the oscillation in current versus gate voltage. While C-G is indeed the average value of C-SETT over one period, C-SETT can in fact differ substantially from that value, depending on the applied voltages. This has important consequences for maximizing the sensitivity of SET charge electrometers when a large stray capacitance is present. (C) 2000 American Institute of Physics. [S0021-8979(00)07812-9]. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Natl Inst Stand & Technol, Boulder, CO 80303 USA. NR 8 TC 11 Z9 11 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD JUN 15 PY 2000 VL 87 IS 12 BP 8570 EP 8574 DI 10.1063/1.373580 PG 5 WC Physics, Applied SC Physics GA 319MU UT WOS:000087346400048 ER PT J AU Ortigoso, J Hougen, JT AF Ortigoso, J Hougen, JT TI K-scrambling in a near-symmetric top molecule containing an excited noncoaxial internal rotor SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID ROTATIONAL ENERGY SURFACES; FLUORESCENCE POLARIZATION; NONLINEAR DYNAMICS; ASYMMETRIC-TOP; ACETALDEHYDE; STATES; MODEL AB Classical trajectories on rotational energy surfaces and coherent-state quantum projections have been used to study an asymmetric-top molecule containing a freely rotating internal symmetric top whose symmetry axis is not coincident with a principal axis of the molecule. Stationary points on the rotational energy surface, which strongly influence the trajectories, increase in number from two to four to six as J/n increases from zero to infinity (where J is the total and n is the free-internal-rotor angular momentum). For some J/n values trajectories can arise that sample a large fraction of K values (where K is the z-axis projection of J), corresponding in quantum wave functions to extensive K mixing in the symmetric-top basis set \J,K]. When such mixing cannot be made small for any choice of z axis, we call it K scrambling. For typical values of the torsion-rotation coupling parameter rho, rotational eigenfunctions for a given J and torsional state turn out to be quite different from eigenfunctions for the same J in some other torsional state. Nonzero rotational overlap integrals are then distributed among many rotational functions for each (n,n') pair, which may, in turn, contribute to internal rotation enhancement of intramolecular vibrational energy redistribution. We have also examined near-free-rotor levels of our test molecule acetaldehyde, which arise for excitation of ten or more quanta of methyl group torsion, and find that barrier effects do not change the qualitative picture obtained from the free-rotor treatment. (C) 2000 American Institute of Physics. [S0021-9606(00)00823-0]. C1 CSIC, Inst Estructura Mat, E-28006 Madrid, Spain. Natl Inst Stand & Technol, Opt Technol Div, Gaithersburg, MD 20899 USA. RP Ortigoso, J (reprint author), CSIC, Inst Estructura Mat, Serrano 119, E-28006 Madrid, Spain. RI Ortigoso, Juan/F-1234-2016 NR 25 TC 6 Z9 6 U1 1 U2 5 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD JUN 15 PY 2000 VL 112 IS 23 BP 10212 EP 10220 DI 10.1063/1.481663 PG 9 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 321XC UT WOS:000087479100019 ER PT J AU Anthony, EB Bastian, MJ Bierbaum, VM Leone, SR AF Anthony, EB Bastian, MJ Bierbaum, VM Leone, SR TI Laser probing of rotational-state-dependent velocity distributions of N-2(+) (nu('')=0,J) drifted in He SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID INDUCED FLUORESCENCE MEASUREMENTS; TRANSFORM DOPPLER SPECTROSCOPY; VIBRATIONAL-RELAXATION; TRANSPORT-PROPERTIES; HYPERFINE-STRUCTURE; ION MOBILITY; ENERGY-DISTRIBUTIONS; TUBE EXPERIMENTS; KINETIC-THEORY; PLASMA AB Rotational state-resolved velocity component distribution functions of N-2(+) (nu' = 0) drifted in helium are measured in a flow-drift apparatus by the technique of single-frequency laser-induced fluorescence (LIF). A single-mode ring dye laser is used to probe Doppler profiles of various rotational lines in the R-branch of the (nu',nu ") = (0,0) band of the B (2)Sigma(u)(+)-X (2)Sigma(g)(+) system at 390 nm, with the laser propagation direction set either parallel or perpendicular to the drift field. A small but definite (3%) increase in ion mobility with increasing rotational state from J = 13.5 to J = 22.5 is observed at a fixed field strength of 12 Td. Mobilities of J = 15.5 measured over the range of 1.5-16 Td yield a K-0(0) of 22.0 cm(2) V-1 s(-1) and are in good agreement with earlier arrival-time measurements. Parallel translational temperatures are found to be significantly higher than perpendicular temperatures; a difference of at least 140 K between these temperatures is measured for J = 15.5 at 16 Td. No discernible difference between the parallel translational temperatures for different rotational states is observed. There is evidence for a small degree of positive skewness (third central moment) in the parallel velocity component distributions, the first observation of such an effect in a molecular ion-atomic buffer system. Previous results that indicated poor agreement between CO+-He pulsed-field arrival-time and LIF mobilities are discussed; the LIF results were most likely hampered by space-charge effects. (C) 2000 American Institute of Physics. [S0021-9606(00)01021-7]. C1 Natl Inst Stand & Technol, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. Univ Colorado, Dept Phys, Boulder, CO 80309 USA. Univ Colorado, Dept Chem & Biochem, Boulder, CO 80309 USA. RP Anthony, EB (reprint author), Natl Inst Stand & Technol, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. NR 55 TC 9 Z9 9 U1 1 U2 2 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD JUN 15 PY 2000 VL 112 IS 23 BP 10269 EP 10281 DI 10.1063/1.481667 PG 13 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 321XC UT WOS:000087479100025 ER PT J AU Yang, XQ Anderson, JL AF Yang, XQ Anderson, JL TI Correction of systematic errors in coupled GCM forecasts SO JOURNAL OF CLIMATE LA English DT Article ID GENERAL-CIRCULATION MODEL; OCEAN-ATMOSPHERE MODEL; NINO SOUTHERN OSCILLATION; TROPICAL PACIFIC CLIMATE; EL-NINO; INTERANNUAL VARIABILITY; SEASONAL CYCLE; DATA ASSIMILATION; SIMULATION; PREDICTABILITY AB The prognostic tendency (PT) correction method is applied in an attempt to reduce systematic errors in coupled GCM seasonal forecasts. The PT method computes the systematic initial tendency error (SITE) of the coupled model and subtracts it from the discrete prognostic equations. In this study, the PT correction is applied only to the three-dimensional ocean temperature. The SITE is computed by calculating a climatologically averaged difference between coupled model initial conditions and resulting forecasts at very short lead times and removing the observed mean seasonal tendency. Two sets of coupled GCM forecasts, one using an annual mean SITE correction and the other using a SITE correction that is a function of season, are compared with a control set of uncorrected forecasts. Each set consists of 17 12-month forecasts starting on 1 January from 1980 through 1996. The PT correction is found to be an effective method for maintaining a more realistic forecast climatology by reducing systematic ocean temperature errors that lead to a relaxation of the tropical Pacific thermocline slope and a weak tropical SST annual cycle in the control set. The annual mean PT correction, which allows the model to freely generate its own seasonal cycle, leads to increased prediction skill for tropical Pacific SSTs while the seasonally varying PT correction has no impact on this skill. Physical mechanisms responsible for improvements in the coupled model's annual cycle and forecast skill are investigated. The annual mean structure of the tropical Pacific thermocline is found to be essential For producing a realistic SST annual cycle. The annul mean PT correction helps to maintain a realistic thermocline slope that allows surface winds to impact the annual cycle of SST in the eastern Pacific. Forecast skill is increased if the coupled model correctly captures dynamical modes related to ENSO. The annual mean correction leads to a model ENSO that is best characterized as a delayed oscillator mode while the control model appears to have a more stationary ENSO mode; this apparently has a positive impact on ENSO forecast skill in the PT corrected model. C1 Princeton Univ, NOAA, GFDL, Princeton, NJ 08542 USA. Princeton Univ, Program Atmospher & Ocean Sci, Princeton, NJ 08544 USA. RP Anderson, JL (reprint author), Princeton Univ, NOAA, GFDL, POB 308, Princeton, NJ 08542 USA. RI Yang, Michael/G-9716-2013 NR 51 TC 18 Z9 21 U1 1 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 JUN 15 PY 2000 VL 13 IS 12 BP 2072 EP 2085 DI 10.1175/1520-0442(2000)013<2072:COSEIC>2.0.CO;2 PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 324PU UT WOS:000087631200007 ER PT J AU Penland, C Flugel, M Chang, P AF Penland, C Flugel, M Chang, P TI Identification of dynamical regimes in an intermediate coupled ocean-atmosphere model SO JOURNAL OF CLIMATE LA English DT Article ID NINO-SOUTHERN OSCILLATION; SEA-SURFACE TEMPERATURE; EL-NINO; TROPICAL PACIFIC; SEASONAL CYCLE; INTERANNUAL VARIABILITY; EQUATORIAL PACIFIC; ENSO; PREDICTABILITY; PREDICTION AB Earlier studies have used a series of tests based on linear inverse modeling (LIM) to investigate the proposition that the dynamics of observed tropical Indo-Pacific sea surface temperature anomalies may be described as a stable linear system driven by spatially coherent stochastic forcing. Previous verifications of these tests' dependability have been performed on highly idealized systems such as the chaotic Lorenz model. In this study, LIM and tests for validity of its underlying assumptions are performed on the output of an intermediate coupled ocean-atmosphere numerical model. Five cases are considered: 1) a coupled ocean-atmosphere, with the dynamics dominated by a single, slightly unstable mode (case 1); 2) a model equivalent to case 1, but with additional stochastic forcing (case 2); 3) a coupled ocean-atmosphere as in case 2, but with the dynamics adjusted so as to be in the stable regime (case 3); 4) yet another coupled case (case 4) but with a stable dynamical regime farther away from the bifurcation point than in case 3; and 5) an uncoupled ocean, driven by a stochastic atmosphere (case 5). Although none of the cases passed the tests for linearity as well as the data considered by Penland and Sardeshmukh, cases 1, 2, and 3 were identified as more strongly nonlinear systems than cases 4 and 5. The authors' results support the reliability of the tests performed by Penland and Sardeshmukh on Comprehensive Ocean-Atmosphere Data Set data, which suggested that ENSO is likely to reside in a stable dynamical regime maintained by stochastic forcing. C1 NOAA, CIRES, Climate Diagnost Ctr, Boulder, CO 80303 USA. Texas A&M Univ, Dept Oceanog, College Stn, TX 77843 USA. RP Penland, C (reprint author), NOAA, CIRES, Climate Diagnost Ctr, 325 Broadway, Boulder, CO 80303 USA. RI Chang, Ping /A-1642-2013 OI Chang, Ping /0000-0002-9085-0759 NR 47 TC 24 Z9 24 U1 1 U2 1 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 JUN 15 PY 2000 VL 13 IS 12 BP 2105 EP 2115 DI 10.1175/1520-0442(2000)013<2105:IODRIA>2.0.CO;2 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 324PU UT WOS:000087631200009 ER PT J AU Elliott, WP Ross, RJ AF Elliott, WP Ross, RJ TI Estimated impacts on climate records of adaptive strategies for scheduling radiosondes SO JOURNAL OF CLIMATE LA English DT Article AB Possible changes to the North American Atmospheric Observing System that are under discussion include the scheduling of radiosonde launches according to synoptic conditions. The authors estimate biases in longterm monthly mean tropospheric temperature and humidity resulting from reducing the number of radiosonde launches at a site depending on synoptic conditions. The sign and magnitudes of the biases vary considerably with geographic location and sometimes with season. Such biases would contaminate the upper-air climatology and complicate the calculation of climate trends. Approaches for minimizing these biases are explored. C1 NOAA, Air Resources Lab, R ARL, Silver Spring, MD 20910 USA. RP Ross, RJ (reprint author), NOAA, Air Resources Lab, R ARL, 1315 East West Highway, Silver Spring, MD 20910 USA. NR 6 TC 5 Z9 5 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 JUN 15 PY 2000 VL 13 IS 12 BP 2116 EP 2120 DI 10.1175/1520-0442(2000)013<2116:EIOCRO>2.0.CO;2 PG 5 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 324PU UT WOS:000087631200010 ER PT J AU Overland, JE McNutt, SL Groves, J Salo, S Andreas, EL Persson, POG AF Overland, JE McNutt, SL Groves, J Salo, S Andreas, EL Persson, POG TI Regional sensible and radiative heat flux estimates for the winter Arctic during the Surface Heat Budget of the Arctic Ocean (SHEBA) experiment SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID SEA-ICE; ENERGY BUDGETS; BEAUFORT SEA; TEMPERATURE; LEADS; COEFFICIENTS; POLYNYAS; PACK AB We estimate the influence of the mosaic distribution of surface temperatures of sea ice on regional surface sensible and radiative heat fluxes on the basis of advanced very high resolution radiometer (AVHRR) temperatures. The AVHRR data were used to derive similar to 1 km(2) surface temperature values for 100 x 100 km(2) regions. Regional flux estimates are compared to direct flux measurements taken during the Surface Heat Budget of the Arctic Ocean (SHEBA) experiment in the Beaufort Sea. We describe 48 cases of clear-sky conditions between December 1997 and February 1998. The distribution of surface temperatures within each region is skewed: most temperatures fall near the value observed at the ice camp, but the distribution has a warm tail corresponding to subregions with thinner ice. Sensible heat fluxes at the ice camp were downward, from the air to the ice; Although the camp was representative of the majority of the region, the upward flux from thin ice generally balanced the downward flux to thicker ice, suggesting a regional equilibrium of near-zero sensible heat flux. This was true whether the net downward flux at the camp was large or small or whether the ice was less compact, as in January, or more compact, as in December and February. The only exception to this generalization occurred when the ice was under strong compression. The net regional radiative loss from the ice surface was similar to 22% greater than that measured on the flee at the SHEBA camp. This increase is due to the fourth-power temperature dependence of the radiative flux acting on the skewed distribution of surface temperatures. The implications for modeling are that sea ice tends toward small net surface sensible heat flux on an aggregate scale, an emergent property of the system, and that parameterizing the regional mosaic of surface temperatures to resolve correctly the radiative balance in winter is important. C1 NOAA, Pacific Marine Environm Lab, Seattle, WA 98115 USA. USA, Cold Reg Res & Engn Lab, Hanover, NH 03755 USA. NOAA, CIRES, ETL, Boulder, CO 80303 USA. Univ Alaska, Inst Geophys, Fairbanks, AK USA. RP Overland, JE (reprint author), NOAA, Pacific Marine Environm Lab, 7600 Sand Point Way Ne, Seattle, WA 98115 USA. NR 21 TC 19 Z9 19 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-OCEANS JI J. Geophys. Res.-Oceans PD JUN 15 PY 2000 VL 105 IS C6 BP 14093 EP 14102 DI 10.1029/1999JC000010 PG 10 WC Oceanography SC Oceanography GA 324NB UT WOS:000087627300011 ER PT J AU Gilson, HSR Krauss, M AF Gilson, HSR Krauss, M TI Response to "Comment on 'Reinterpretation of the spectra of hydrated Co++: An ab initio study'" SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID COBALT(II); TEMPERATURES; MOLECULES; WATER; IONS C1 NIST, Ctr Adv Res Biotechnol, Rockville, MD 20850 USA. RP Krauss, M (reprint author), NIST, Ctr Adv Res Biotechnol, 9600 Gudelsky Dr, Rockville, MD 20850 USA. NR 16 TC 3 Z9 3 U1 1 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 JUN 15 PY 2000 VL 104 IS 23 BP 5653 EP 5654 DI 10.1021/jp993112p PG 2 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 327DW UT WOS:000087778800034 ER PT J AU Dunn, ML Ledbetter, H AF Dunn, ML Ledbetter, H TI Micromechanically-based acoustic characterization of the fiber orientation distribution function of morphologically textured short-fiber composites: prediction of thermomechanical and physical properties SO MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING LA English DT Article; Proceedings Paper CT NSF Symposium on Micromechanic Modeling of Industrial Materials CY JUL 20-22, 1998 CL UNIV WASHINGTON, SEATTLE, WASHINGTON SP Natl Sci Fdn, Minerals Met & Mat Soc, AIME, Amer Soc Met, Amer Soc Mech Engineers, Japan Inst Met, Nippon Steel corp, Kobe Steel Ltd, Nissin Steel Co Ltd, Ryobi N Amer, Awaji Sangyo, Japan Steel Works HO UNIV WASHINGTON DE short-fiber composite; fiber orientation distribution function; acoustics ID THERMAL-EXPANSION; REINFORCED COMPOSITES; POROUS MATERIALS; ELASTIC-MODULI; IMAGE-ANALYSIS; ANISOTROPY; INCLUSIONS; PLASTICITY; ENERGY AB We apply our recently-developed acoustic approach to characterize the fiber orientation distribution function (ODF) of short fiber composites to predict relevant anisotropic thermomechanical properties of such composites. The acoustic approach consists of a tight coupling of acoustic velocity measurements and micromechanics modeling. It can not completely characterize the ODF, but delivers information regarding lower-order terms of the ODF when expanded in a series of generalized spherical harmonics. We apply the approach to two composite material systems (SiC/Al and glass/polyphenylene sulfide) with different overall symmetry (transversely istropic and orthotropic). For the two composites, we predict the overall anisotropic elastic moduli, thermal expansion coefficients, elastic-plastic constitutive behavior, and thermal conductivity. The predictions agree well with measurements in all cases; this demonstrates that the lower-order terms of the ODF expansion are sufficient to characterize a large number of other physical and mechanical properties of the composite, when coupled with the appropiate models. As a result, we conclude that the combination of acoustic velocity measurements and micromechanics modeling provides a powerful approach to characterize the fiber ODF, and its effect on overall composite properties. (C) 2000 Elsevier Science S.A. All rights reserved. C1 Univ Colorado, Dept Mech Engn, Boulder, CO 80309 USA. Natl Inst Stand & Technol, Mat Sci & Engn Lab, Boulder, CO 80303 USA. RP Dunn, ML (reprint author), Univ Colorado, Dept Mech Engn, Boulder, CO 80309 USA. OI DUNN, MARTIN/0000-0002-4531-9176 NR 32 TC 6 Z9 6 U1 2 U2 5 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 JUN 15 PY 2000 VL 285 IS 1-2 BP 56 EP 61 DI 10.1016/S0921-5093(00)00666-3 PG 6 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA 328JZ UT WOS:000087848800011 ER PT J AU Ledbetter, H Dunn, ML AF Ledbetter, H Dunn, ML TI Equivalence of Eshelby inclusion theory and Wechsler-Lieberman-Read, Bowles-Mackenzie martensite-crystallography theories SO MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING LA English DT Article; Proceedings Paper CT NSF Symposium on Micromechanic Modeling of Industrial Materials CY JUL 20-22, 1998 CL UNIV WASHINGTON, SEATTLE, WASHINGTON SP Natl Sci Fdn, Minerals Met & Mat Soc, AIME, Amer Soc Met, Amer Soc Mech Engineers, Japan Inst Met, Nippon Steel corp, Kobe Steel Ltd, Nissin Steel Co Ltd, Ryobi N Amer, Awaji Sangyo, Japan Steel Works HO UNIV WASHINGTON DE crystallography; habit plane; inclusion theory; invariant-plane-strain theories; martensite; orientation relationships; shape change; steel; twins ID MINIMIZATION; ENERGY AB We consider the relationship of the Eshelby inclusion theory to the Wechsler-Lieberman-Read, Bowles-Mackenzie (WLR-BM) theories of martensite crystallography. The WLR-BM theories proceed by solving for an invariant plane strain and by assuming a lattice invariant deformation, often (110) twinning or its equivalent. Eshelby's theory estimates the strain, stress, and minimum strain energy of an ellipsoidal inclusion (or inhomogeneity) transforming in a constraining matrix. We use a Lagrangean finite-strain definition for the eigenstrain. We pay special attention to the crystallographic twinning plane and to twin coherency. specifically how they affect the eigenstrain. Focusing on many crystallographic features, including the habit plane and shape change, we find identical (within numerical accuracy) predictions of the crystallographic and energy-minimization theories for the Fe-31Ni f.c.c.-b.c.c. steel transformation. which shows enormous principal strains (0.13, 0.13, 0.20). The identity surprises us because we substitute finite strains into the infinitesimal strain inclusion theory. The inclusion-model contains all crystallographic features and. thus, is complete. This approach to martensite crystallography offers enormous new research possibilities. We enumerate twelve. Published by Elsevier Science S.A. C1 Natl Inst Stand & Technol, Mat Sci & Engn Lab, Boulder, CO 80303 USA. Univ Colorado, Dept Mech Engn, Boulder, CO 80309 USA. RP Ledbetter, H (reprint author), Natl Inst Stand & Technol, Mat Sci & Engn Lab, 325 Broadway, Boulder, CO 80303 USA. OI DUNN, MARTIN/0000-0002-4531-9176 NR 20 TC 18 Z9 19 U1 0 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 JUN 15 PY 2000 VL 285 IS 1-2 BP 180 EP 185 DI 10.1016/S0921-5093(00)00697-3 PG 6 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA 328JZ UT WOS:000087848800027 ER PT J AU Soininen, JA Shirley, EL AF Soininen, JA Shirley, EL TI Effects of electron-hole interaction on the dynamic structure factor: Application to nonresonant inelastic x-ray scattering SO PHYSICAL REVIEW B LA English DT Article ID AB-INITIO CALCULATION; INSULATORS; SEMICONDUCTORS; METAL; LI AB We present a first-principles scheme for calculating the dynamic structure factor for conventional semiconductors and insulators. The dynamic structure factor relates closely to the inelastic x-ray scattering double-differential cross section for valence electrons, an application that we consider, but it is also probed using other techniques, such as electron energy-loss spectroscopy. In the present scheme the electron-hole interaction is taken into account. Theoretical results are compared with nonresonant inelastic x-ray scattering results for LiF, diamond, and wurtzite GaN. We show the importance of including the electron-hole interaction. Some other properties of an electron-hole pair in these materials are also studied. C1 Univ Helsinki, Dept Phys, FIN-00014 Helsinki, Finland. Natl Inst Stand & Technol, Phys Lab, Opt Technol Div, Gaithersburg, MD 20899 USA. RP Univ Helsinki, Dept Phys, POB 9, FIN-00014 Helsinki, Finland. NR 20 TC 26 Z9 26 U1 0 U2 4 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2469-9950 EI 2469-9969 J9 PHYS REV B JI Phys. Rev. B PD JUN 15 PY 2000 VL 61 IS 24 BP 16423 EP 16429 DI 10.1103/PhysRevB.61.16423 PG 7 WC Physics, Condensed Matter SC Physics GA 331FV UT WOS:000088008400027 ER PT J AU Woodward, JT Walker, ML Meuse, CW Vanderah, DJ Poirier, GE Plant, AL AF Woodward, JT Walker, ML Meuse, CW Vanderah, DJ Poirier, GE Plant, AL TI Effect of an oxidized gold substrate on alkanethiol self-assembly SO LANGMUIR LA English DT Article ID X-RAY-DIFFRACTION; MONOLAYERS; SURFACES; SPECTROSCOPY; ADSORPTION; OZONE; REORGANIZATION; STABILITY; OXIDATION; AU(111) AB UV-cleaned gold substrates incubated in solutions of alkanethiol show islands on the monolayer surface when imaged with noncontact atomic force microscopy (AFM). The height of the islands above the monolayer is approximately twice the height of the alkanethiol monolayer, and the diameter of the islands is 20-200 nm. These islands are easily pushed aside during contact mode AFM imaging without damaging the underlying monolayer. Islands are observed on gold substrates exposed to solutions of octadecane-, hexadecane-, and dodecanethiol and 1'-thiahexa(ethylene oxide)-1-octadecane at 0.01-1.0 mM concentrations in ethanol and hexadecane. AFM on samples with submonolayer coverage shows that the islands are not observed until the late stages of monolayer formation. Islands are not observed on freshly deposited gold substrates or on UV-cleaned gold substrates that are exposed to ethanol for longer than 10 min prior to incubation in alkanethiol solutions. We conclude that the island formation is associated with oxidation of the gold surface and that the islands are primarily composed of alkanethiol. We hypothesize that the stability of these structures may be due to the formation of multimolecular complexes of alkanethiols. C1 Natl Inst Stand & Technol, Div Biotechnol, Surface & Microanal Sci Div, Gaithersburg, MD 20899 USA. Natl Inst Stand & Technol, Proc Measurements Div, Gaithersburg, MD 20899 USA. RP Woodward, JT (reprint author), Natl Inst Stand & Technol, Div Biotechnol, Surface & Microanal Sci Div, Gaithersburg, MD 20899 USA. NR 28 TC 28 Z9 29 U1 0 U2 22 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0743-7463 J9 LANGMUIR JI Langmuir PD JUN 13 PY 2000 VL 16 IS 12 BP 5347 EP 5353 DI 10.1021/la991672+ PG 7 WC Chemistry, Multidisciplinary; Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA 322LF UT WOS:000087510500021 ER PT J AU Band, YB Trippenbach, M Burke, JP Julienne, PS AF Band, YB Trippenbach, M Burke, JP Julienne, PS TI Elastic scattering loss of atoms from colliding Bose-Einstein condensate wave packets SO PHYSICAL REVIEW LETTERS LA English DT Article ID TRAPPED GASES; DIFFRACTION; DYNAMICS AB Bragg diffraction of atoms by light waves can create high momentum components in a Bose-Einstein condensate. Collisions between atoms from two distinct momentum wave packets cause elastic scattering that can remove a significant fraction of atoms from the wave packets and cause the formation of a spherical shell of scattered atoms. We develop a slowly varying envelope technique that includes the effects of this loss on the condensate dynamics described by the Cross-Pitaevski equation. Three-dimensional numerical calculations are presented for two experimental situations: passage of a moving daughter condensate through a nonmoving parent condensate, and four-wave mixing of matter waves. C1 Ben Gurion Univ Negev, Dept Chem, IL-84105 Beer Sheva, Israel. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Univ Warsaw, Opt Div, Inst Expt Phys, PL-00681 Warsaw, Poland. RP Band, YB (reprint author), Ben Gurion Univ Negev, Dept Chem, IL-84105 Beer Sheva, Israel. RI Julienne, Paul/E-9378-2012 OI Julienne, Paul/0000-0002-5494-1442 NR 17 TC 62 Z9 63 U1 1 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 JUN 12 PY 2000 VL 84 IS 24 BP 5462 EP 5465 DI 10.1103/PhysRevLett.84.5462 PG 4 WC Physics, Multidisciplinary SC Physics GA 322RH UT WOS:000087522200002 ER PT J AU Lyons, SN Sandwell, DT Smith, WHF AF Lyons, SN Sandwell, DT Smith, WHF TI Three-dimensional estimation of elastic thickness under the Louisville Ridge SO JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH LA English DT Article ID EMPEROR SEAMOUNT CHAIN; PACIFIC-OCEAN-BASIN; SATELLITE ALTIMETRY; GEOID HEIGHTS; BATHYMETRIC PREDICTION; EXPERIMENTAL ISOSTASY; GRAVITY ANOMALIES; HAWAIIAN-ISLANDS; FLEXURE; LITHOSPHERE AB A three-dimensional approach to estimating elastic thickness is presented which uses dense satellite altimetry and sparse ship bathymetry. This technique is applied to the Louisville Ridge system to study the tectonic history of the region. The inversion is performed as both a first-order approximation and a nonlinear relationship between gravity and topography based on Parker's [1973] equation. While the higher-order effect on the gravity anomaly is nearly zero for most of the region, the magnitude is significant over the summits of the ridge. Nevertheless, the inclusion of the nonlinear terms has only a minor influence on the elastic thickness estimate within each region, lowering the value by similar to 1-2 km compared with the linear result. The incorrect assumption of two dimensionality for circular features exhibits a marked effect on the gravitational anomaly, resulting in false sidelobe structure of nearly 20 mGal for large seamounts. Our elastic thickness estimates are compared with the contradictory values obtained in previous studies by Cazenave and Dominh [1984] and Watts et al. [1988]. We find an increasing elastic thickness along the chain from southeast to northwest, with a discontinuity along the Wishbone scarp. The jump in elastic thickness values northwest of the scarp appears to be an indication of an age discontinuity caused by an extinct spreading center north of the ridge. C1 Univ Calif San Diego, Scripps Inst Oceanog, La Jolla, CA 92093 USA. NOAA, Lab Satellite Altimetry, Silver Spring, MD 20910 USA. RP Univ Calif San Diego, Scripps Inst Oceanog, MC0225, La Jolla, CA 92093 USA. EM slyons@radar.ucsd.edu; sandwell@geosat.ucsd.edu; wsmith@nodc.noaa.gov RI Smith, Walter/F-5627-2010; OI Smith, Walter/0000-0002-8814-015X; Sandwell, David/0000-0001-5657-8707 NR 46 TC 22 Z9 23 U1 0 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 JUN 10 PY 2000 VL 105 IS B6 BP 13239 EP 13252 DI 10.1029/2000JB900065 PG 14 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 324NJ UT WOS:000087628000007 ER PT J AU Sharpless, KE Margolis, S Thomas, JB AF Sharpless, KE Margolis, S Thomas, JB TI Determination of vitamins in food-matrix Standard Reference Materials SO JOURNAL OF CHROMATOGRAPHY A LA English DT Article DE Standard Reference Materials; food analysis; vitamins ID LIQUID-CHROMATOGRAPHIC MEASUREMENT; ASCORBIC-ACID; BIOLOGICAL SAMPLES; VALUE ASSIGNMENT; HUMAN SERUM; CAROTENOIDS; TOCOPHEROL; COMPOSITE; RETINOL; ISOMERS AB In recent years, the National Institute of Standards and Technology (MIST) has developed several food-matrix Standard Reference Materials (SRMs) characterized for vitamins and other organic nutrients. MIST uses several "modes" for assignment of analyte concentrations in SRMs, one of which includes the use of data provided by collaborating laboratories. Certification modes and liquid chromatographic methods that were used by MIST for value assignment of vitamin concentrations in recently introduced food-matrix SRMs are described in this paper. These materials and methods include vitamins D and E in coconut oil (SRM 1563) by gravimetry and multi-dimensional liquid chromatography (LC); vitamins A, E, and several B vitamins by reversed-phase LC and vitamin C by ion-exchange chromatography in infant formula (SRM 1846); and carotenoids and vitamins A and E by reversed-phase liquid chromatography in a baby food composite (SRM 2383). (C) 2000 Published by Elsevier Science B.V. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Sharpless, KE (reprint author), Natl Inst Stand & Technol, 100 Bureau Dr,Stop 8392, Gaithersburg, MD 20899 USA. OI Sharpless, Katherine/0000-0001-6569-198X NR 28 TC 14 Z9 14 U1 0 U2 3 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 JUN 9 PY 2000 VL 881 IS 1-2 BP 171 EP 181 DI 10.1016/S0021-9673(00)00260-0 PG 11 WC Biochemical Research Methods; Chemistry, Analytical SC Biochemistry & Molecular Biology; Chemistry GA 327GX UT WOS:000087787000013 PM 10905701 ER PT J AU da Costa, CT Horton, D Margolis, SA AF da Costa, CT Horton, D Margolis, SA TI Analysis of anthocyanins in foods by liquid chromatography, liquid chromatography-mass spectrometry and capillary electrophoresis SO JOURNAL OF CHROMATOGRAPHY A LA English DT Review DE reviews; food analysis; wine; grapes; fruits; anthocyanins ID LOW-DENSITY-LIPOPROTEIN; PIGMENT COMPOSITION; VITIS-VINIFERA; ACYLATED ANTHOCYANINS; ZONE-ELECTROPHORESIS; JUICE PIGMENTATION; HPLC SEPARATION; PHENOLIC-ACIDS; RED WINES; COLOR AB This article reviews recent developments in the methodology for the measurement of anthocyanins that offer several advantages over classical methods of analysis. The use of UV-diode array and mass spectrometric (MS) detectors, with improved methods of liquid chromatography analysis has facilitated identification of these analytes. The use of capillary electrophoresis (CE) analysis of the anthocyanins under acid conditions has significantly increased peak resolution and improved the detection limits by several orders of magnitude. CE offers the advantage of economies of very small sample size, very small solvent consumption, and short analysis times along with the future possibility of being combined with MS detection. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Natl Inst Stand & Technol, Div Analyt Chem, Gaithersburg, MD 20899 USA. Univ Evora, Dept Chem, P-7000 Evora, Portugal. American Univ, Dept Chem, Washington, DC 20216 USA. RP Margolis, SA (reprint author), Natl Inst Stand & Technol, Div Analyt Chem, Gaithersburg, MD 20899 USA. RI Barrocas Dias, Cristina/S-6824-2016 OI Barrocas Dias, Cristina/0000-0002-1707-2209 NR 62 TC 98 Z9 105 U1 8 U2 43 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 JUN 9 PY 2000 VL 881 IS 1-2 BP 403 EP 410 DI 10.1016/S0021-9673(00)00328-9 PG 8 WC Biochemical Research Methods; Chemistry, Analytical SC Biochemistry & Molecular Biology; Chemistry GA 327GX UT WOS:000087787000035 PM 10905723 ER PT J AU Dalluge, JJ Nelson, BC AF Dalluge, JJ Nelson, BC TI Determination of tea catechins SO JOURNAL OF CHROMATOGRAPHY A LA English DT Review DE tea; food analysis; reviews; catechins; phenolic compounds ID PERFORMANCE LIQUID-CHROMATOGRAPHY; MICELLAR ELECTROKINETIC CHROMATOGRAPHY; GREEN TEA; MASS-SPECTROMETRY; CAPILLARY-ELECTROPHORESIS; INDIVIDUAL CATECHINS; HUMAN PLASMA; BLACK TEA; (-)-EPIGALLOCATECHIN GALLATE; ELECTROSPRAY-IONIZATION AB An overview of analytical methods for the measurement of biologically important tea catechins is presented. Liquid chromatography and capillary electrophoresis are the most cited techniques for catechin separation, identification and quantitation. Liquid chromatography with ultraviolet detection is frequently used; however, mass spectrometry, electrochemical, fluorescence and chemiluminescence detection are also utilized in cases where more sensitive or selective detection is needed. Two modes of capillary electrophoresis, capillary zone electrophoresis and micellar electrokinetic capillary chromatography, have been employed for the determination of catechins. Both modes of capillary electrophoresis are based on ultraviolet detection. Additional analytical techniques, such as gas chromatography, thin-layer chromatography, paper chromatography, spectrophotometry, biosensing, chemiluminescence and nuclear magnetic resonance spectroscopy have also been utilized for the determination of catechins and are reviewed herein. (C) 2000 Published by Elsevier Science B.V. C1 Natl Inst Stand & Technol, Div Analyt Chem, Chem Sci & Technol Lab, Gaithersburg, MD 20899 USA. RP Dalluge, JJ (reprint author), Natl Inst Stand & Technol, Div Analyt Chem, Chem Sci & Technol Lab, 100 Bur Dr,Stop 8392, Gaithersburg, MD 20899 USA. EM joseph.dalluge@nist.gov NR 77 TC 116 Z9 125 U1 4 U2 34 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 JUN 9 PY 2000 VL 881 IS 1-2 BP 411 EP 424 DI 10.1016/S0021-9673(00)00062-5 PG 14 WC Biochemical Research Methods; Chemistry, Analytical SC Biochemistry & Molecular Biology; Chemistry GA 327GX UT WOS:000087787000036 PM 10905724 ER PT J AU Twine, TE Kustas, WP Norman, JM Cook, DR Houser, PR Meyers, TP Prueger, JH Starks, PJ Wesely, ML AF Twine, TE Kustas, WP Norman, JM Cook, DR Houser, PR Meyers, TP Prueger, JH Starks, PJ Wesely, ML TI Correcting eddy-covariance flux underestimates over a grassland SO AGRICULTURAL AND FOREST METEOROLOGY LA English DT Article DE eddy-covariance; friction velocity; evapotranspiration flux ID LATENT-HEAT FLUX; WATER-VAPOR; BOWEN-RATIO; ENERGY-BALANCE; CARBON-DIOXIDE; PINE FOREST; SURFACE; EXCHANGES; SYSTEMS; ERRORS AB Independent measurements of the major energy balance flux components are not often consistent with the principle of conservation of energy. This is referred to as a lack of closure of the surface energy balance. Most results in the literature have shown the sum of sensible and latent heat fluxes measured by eddy covariance to be less than the difference between net radiation and soil heat fluxes. This under-measurement of sensible and latent heat fluxes by eddy-covariance instruments has occurred in numerous field experiments and among many different manufacturers of instruments. Four eddy-covariance systems consisting of the same models of instruments were set up side-by-side during the Southern Great Plains 1997 Hydrology Experiment and all systems under-measured fluxes by similar amounts. One of these eddy-covariance systems was collocated with three other types of eddy-covariance systems at different sites; all of these systems under-measured the sensible and latent-heat fluxes. The net radiometers and soil heat flux plates used in conjunction with the eddy-covariance systems were calibrated independently and measurements of net radiation and soil heat flux showed little scatter for various sites. The 10% absolute uncertainty in available energy measurements was considerably smaller than the systematic closure problem in the surface energy budget, which varied from 10 to 30%. When available-energy measurement errors are known and modest, eddy-covariance measurements of sensible and latent heat fluxes should be adjusted for closure. Although the preferred method of energy balance closure is to maintain the Bowen-ratio, the method for obtaining closure appears to be less important than assuring that eddy-covariance measurements are consistent with conservation of energy. Based on numerous measurements over a sorghum canopy, carbon dioxide fluxes, which are measured by eddy covariance, are underestimated by the same factor as eddy covariance evaporation measurements when energy balance closure is not achieved. Published by Elsevier Science B.V. C1 Univ Wisconsin, Dept Atmospher & Ocean Sci, Madison, WI 53706 USA. USDA ARS, Hydrol Lab, Beltsville, MD 20705 USA. Univ Wisconsin, Dept Soil Sci, Madison, WI 53706 USA. Argonne Natl Lab, Argonne, IL 60439 USA. NASA, Goddard Space Flight Ctr, Hydrol Sci Branch, Greenbelt, MD 20771 USA. Oak Ridge Natl Lab, NOAA, Atmospher Turbulence & Diffus, Oak Ridge, TN 37831 USA. USDA ARS, Natl Soil Tilth Lab, Ames, IA 50011 USA. USDA ARS, Grazinglands Res Lab, El Reno, OK 73036 USA. RP Twine, TE (reprint author), Univ Wisconsin, Dept Atmospher & Ocean Sci, 1225 W Dayton St, Madison, WI 53706 USA. RI Twine, Tracy/H-2337-2013; Houser, Paul/J-9515-2013; Meyers, Tilden/C-6633-2016 OI Twine, Tracy/0000-0002-8457-046X; Houser, Paul/0000-0002-2991-0441; NR 40 TC 805 Z9 855 U1 8 U2 125 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-1923 J9 AGR FOREST METEOROL JI Agric. For. Meteorol. PD JUN 8 PY 2000 VL 103 IS 3 BP 279 EP 300 DI 10.1016/S0168-1923(00)00123-4 PG 22 WC Agronomy; Forestry; Meteorology & Atmospheric Sciences SC Agriculture; Forestry; Meteorology & Atmospheric Sciences GA 322VQ UT WOS:000087530300004 ER PT J AU Schroder, TB Sastry, S Dyre, JC Glotzer, SC AF Schroder, TB Sastry, S Dyre, JC Glotzer, SC TI Crossover to potential energy landscape dominated dynamics in a model glass-forming liquid SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID HARD-SPHERE SYSTEM; SUPERCOOLED LIQUIDS; MOLECULAR-DYNAMICS; VISCOUS-LIQUIDS; MEAN-FIELD; TRANSITION; SIMULATIONS; WATER; RELAXATION; NETWORK AB An equilibrated model glass-forming liquid is studied by mapping successive configurations produced by molecular dynamics simulation onto a time series of inherent structures (local minima in the potential energy). Using this "inherent dynamics" approach we find direct numerical evidence for the long held view that below a crossover temperature, T-x, the liquid's dynamics can be separated into (i) vibrations around inherent structures and (ii) transitions between inherent structures [M. Goldstein, J. Chem. Phys. 51, 3728 (1969)], i.e., the dynamics become "dominated" by the potential energy landscape. In agreement with previous proposals, we find that T-x is within the vicinity of the mode-coupling critical temperature T-c. We further find that near T-x, transitions between inherent structures occur via cooperative, stringlike rearrangements of groups of particles moving distances substantially smaller than the average interparticle distance. (C) 2000 American Institute of Physics. [S0021-9606(00)50122-6]. C1 Natl Inst Stand & Technol, Ctr Theoret & Computat Mat Sci, Gaithersburg, MD 20899 USA. Roskilde Univ, Dept Math & Phys IMFUFA, Roskilde, Denmark. Jawaharlal Nehru Ctr Adv Sci Res, Bangalore 560064, Karnataka, India. RP Schroder, TB (reprint author), Natl Inst Stand & Technol, Ctr Theoret & Computat Mat Sci, Gaithersburg, MD 20899 USA. RI Dyre, Jeppe/L-5000-2015 OI Dyre, Jeppe/0000-0002-0770-5690 NR 46 TC 226 Z9 226 U1 1 U2 25 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD JUN 8 PY 2000 VL 112 IS 22 BP 9834 EP 9840 DI 10.1063/1.481621 PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 319MV UT WOS:000087346500020 ER PT J AU Gay, SC Rainwater, JC Beale, PD AF Gay, SC Rainwater, JC Beale, PD TI Two-dimensional hard dumbbells. I. Fluctuating cell model SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID SOLID-LIQUID EQUILIBRIUM; FREE-VOLUME; MOLECULES; PHASE; FLUID; VAN AB We apply the fluctuating cell model to the calculation of free energies and pressures of high density phases of two-dimensional hard dumbbells using the Metropolis algorithm to generate configurations in the NVT ensemble. The natural logarithm of the average free volume is found to yield a better approximation of the free energy of the system than the value obtained from simple cell theory for all reduced bond lengths except very near the previously calculated hard disk limit. The proposed approximation for the free energy, when used in combination with a semianalytic algorithm to calculate free volumes, is found to be of comparable efficiency to the lattice-coupling method of Frenkel and Ladd. Unlike the simple cell model, the fluctuating cell model is applicable to molecules that freeze into plastic crystals as well as orientationally ordered crystals. We also calculate the distribution of free volumes in the solid phase. The nature of the distribution of free volumes changes abruptly near the hard-disk limit, similarly to the sudden change in validity of the fluctuating cell theory approximation. (C) 2000 American Institute of Physics. [S0021-9606(00)51222-7]. C1 Natl Inst Stand & Technol, Phys & Chem Properties Div, Boulder, CO 80303 USA. Univ Colorado, Dept Phys, Boulder, CO 80309 USA. RP Rainwater, JC (reprint author), Natl Inst Stand & Technol, Phys & Chem Properties Div, M-S 838-08,325 Broadway, Boulder, CO 80303 USA. NR 25 TC 12 Z9 12 U1 0 U2 4 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD JUN 8 PY 2000 VL 112 IS 22 BP 9841 EP 9848 AR PII [S0021-9606(00)51222-7] DI 10.1063/1.481622 PG 8 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 319MV UT WOS:000087346500021 ER PT J AU Gay, SC Rainwater, JC Beale, PD AF Gay, SC Rainwater, JC Beale, PD TI Two-dimensional hard dumbbells. II. Pressure in terms of free volumes and surfaces SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID SPHERE SYSTEMS; STATISTICAL GEOMETRY; CAVITIES; FLUID; CRYSTAL; DISK; LIQUID; SIMULATION; EQUATION; STATE AB For systems of fused-hard-sphere molecules, we relate cavity distributions to free-volume distributions and derive new statistical geometry relations between thermodynamic and cavity properties. From these results, we formulate two different approaches for calculating the pressure of systems of two-dimensional homonuclear hard dumbbells in terms of the geometry of the free volume of a molecule observed over the course of a simulation. We find a simple linear relationship to exist between the compressibility and the average of the ratio of the surface area and volume of the angle-averaged free volumes of the dumbbells. We find excellent agreement between the pressure as calculated via both approaches and the pressure as calculated from simulations. (C) 2000 American Institute of Physics. [S0021-9606(00)51322-1]. C1 Natl Inst Stand & Technol, Phys & Chem Properties Div, Boulder, CO 80303 USA. Univ Colorado, Dept Phys, Boulder, CO 80309 USA. RP Rainwater, JC (reprint author), Natl Inst Stand & Technol, Phys & Chem Properties Div, M-S 838-08,325 Broadway, Boulder, CO 80303 USA. NR 19 TC 4 Z9 4 U1 0 U2 2 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD JUN 8 PY 2000 VL 112 IS 22 BP 9849 EP 9859 DI 10.1063/1.481623 PG 11 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 319MV UT WOS:000087346500022 ER PT J AU Rodriguez, JA Jirsak, T Sambasivan, S Fischer, D Maiti, A AF Rodriguez, JA Jirsak, T Sambasivan, S Fischer, D Maiti, A TI Chemistry of NO2 on CeO2 and MgO: Experimental and theoretical studies on the formation of NO3 SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID FIRST-PRINCIPLES DETERMINATION; DENSITY-FUNCTIONAL THEORY; TOTAL-ENERGY CALCULATIONS; AB-INITIO CALCULATIONS; NITROGEN-DIOXIDE; BONDING MECHANISM; ADSORPTION ENERGY; MGO(100) SURFACE; NITRIC-OXIDE; MOLECULAR-DYNAMICS AB In environmental catalysis the destruction or removal of nitrogen oxides (DeNOx process) is receiving a lot of attention. Synchrotron-based x-ray absorption near-edge spectroscopy, high-resolution photoemission, and first-principles density-functional calculations (DFT-GGA) were used to study the interaction of nitrogen dioxide with CeO2 and MgO. The only product of the reaction of NO2 with pure CeO2 at 300 K is adsorbed nitrate. The NO3 is a thermally stable species which mostly decomposes at temperatures between 450 and 600 K. For the adsorption of NO2 on partially reduced ceria (CeO2-x), there is full decomposition of the adsorbate and a mixture of N, NO, and NO3 coexists on the surface of the oxide at room temperature. Ce3+ cations can assist in the transformation of NO and NO2 in DeNOx operations. Adsorbed NO3 (main product) and NO2 are detected after exposing MgO to NO2 gas. A partial NO2,ads-->NO3,ads transformation is observed on MgO(100) from 150 to 300 K. DFT-GGA calculations show strong bonding interactions for NO2 on Mg sites of this surface, and dicoordination via O, O is more favorable energetically than monocoordination via N. The NO2,ads species disappears from magnesium oxide at temperatures below 600 K, whereas part of the NO3,ads is stable up to temperatures near 800 K. MgO can be very useful as a sorbent for trapping NO2. A general trend is found after comparing the chemical behavior of NO2 on different types of oxides (CeO2, MgO, TiO2, Fe2O3, CuO, ZnO). On all these systems, the main product after adsorbing NO2 at 300 K is nitrate with minor amounts of chemisorbed NO2 and no signs of full decomposition of the adsorbate. This trend and the results of DFT-GGA calculations indicate that NO2 is very efficient for the nitration (i.e., formation of NO3 as a ligand) of metal centers that are missing O neighbors in oxide surfaces. (C) 2000 American Institute of Physics. [S0021-9606(00)71222-0]. C1 Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. Brookhaven Natl Lab, Natl Synchrotron Light Source, Upton, NY 11973 USA. Natl Inst Stand & Technol, Mat Sci & Engn Lab, Gaithersburg, MD 20899 USA. Mol Simulat Inc, San Diego, CA 92121 USA. RP Rodriguez, JA (reprint author), Brookhaven Natl Lab, Dept Chem, Upton, NY 11973 USA. NR 93 TC 79 Z9 80 U1 5 U2 51 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD JUN 8 PY 2000 VL 112 IS 22 BP 9929 EP 9939 AR PII [S0021-9606(00)71222-0] DI 10.1063/1.481629 PG 11 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 319MV UT WOS:000087346500030 ER PT J AU Ngabe, B Bidleman, TF Scott, GI AF Ngabe, B Bidleman, TF Scott, GI TI Polycyclic aromatic hydrocarbons in storm runoff from urban and coastal South Carolina SO SCIENCE OF THE TOTAL ENVIRONMENT LA English DT Article DE polycyclic aromatic hydrocarbons; urban runoff; estuaries; South Carolina ID SOUTHEASTERN UNITED-STATES; PETROLEUM-HYDROCARBONS; ORGANIC CONTAMINANTS; AMBIENT AIR; SEDIMENTS; POLLUTION; ESTUARIES; GEOCHEMISTRY; ENVIRONMENT; MICROLAYER AB Stormwater runoff was collected in urbanized areas of South Carolina to investigate the levels and sources of polycyclic aromatic hydrocarbons (PAHs). Mean concentrations of total PAHs in runoff (Sigma PAHs, 14 compounds), determined by gas chromatography-mass spectrometry, were 5590 ng/l in the city of Columbia and 282 ng/l in the coastal community of Murrells Inlet. Lower concentrations were found in estuarine water at Murrells Inlet (mean = 35 ng/l) and at undeveloped North Inlet estuary (13 ng/l). The PAH profiles in Columbia and Murrells Inlet runoff were similar to those of atmospheric particulate matter and unlike those in used crankcase oil. Examination of the aliphatic fraction of Columbia runoff samples by gas chromatography with flame ionization detection showed patterns that were more similar to used crankcase oil than to urban aerosols. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Meterol Serv Canada, Downsview, ON M3H 5T4, Canada. Univ S Carolina, Dept Chem & Biochem, Columbia, SC 29208 USA. Natl Marine Fisheries Serv, SE Fisheries Sci Ctr, Charleston, SC 29412 USA. RP Ngabe, B (reprint author), Meterol Serv Canada, 4905 Dufferin St, Downsview, ON M3H 5T4, Canada. RI Bidleman, Terry/F-6287-2011 OI Bidleman, Terry/0000-0001-7469-0532 NR 32 TC 63 Z9 72 U1 3 U2 27 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0048-9697 J9 SCI TOTAL ENVIRON JI Sci. Total Environ. PD JUN 8 PY 2000 VL 255 IS 1-3 BP 1 EP 9 DI 10.1016/S0048-9697(00)00422-8 PG 9 WC Environmental Sciences SC Environmental Sciences & Ecology GA 326QK UT WOS:000087746100001 PM 10898390 ER PT J AU Margadonna, S Li, WZ Prassides, K Neumann, DA AF Margadonna, S Li, WZ Prassides, K Neumann, DA TI Rotational dynamics of C-60 in superconducting K3Ba3C60 SO CHEMICAL PHYSICS LETTERS LA English DT Article ID INELASTIC NEUTRON-SCATTERING; DOPED C-60; FULLERIDES; LIBRATIONS; BA AB The orientational dynamics of C-(x) in superconducting K3Ba3C60 are studied by neutron inelastic scattering. Low-energy excitations are present near similar to 6 meV between 150 and 320 K and are assigned to small-amplitude librations of the C-60(9-) ions. They are harder and broader than those measured in K3C60. reflecting the existence of a stronger and more anisotropic orientational potential. The anisotropy and dispersion effects are also larger than those in isostructural Rb6C60, as. a result of positional disorder of the Ba2+ and K+ ions. which reside in distorted tetrahedral interstices. The estimated barrier of the hindrance potential, E-a, is similar to 1.4 eV. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Sussex, Sch Chem Phys & Environm Sci, Fullerene Sci Ctr, Brighton BN1 9QJ, E Sussex, England. Natl Inst Stand & Technol, Ctr Neutron Res, Gaithersburg, MD 20899 USA. RP Prassides, K (reprint author), Univ Sussex, Sch Chem Phys & Environm Sci, Fullerene Sci Ctr, Brighton BN1 9QJ, E Sussex, England. RI Prassides, Kosmas/C-9804-2009; Li, Wenzhi/J-6797-2016 OI Li, Wenzhi/0000-0001-8442-2232 NR 17 TC 2 Z9 2 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2614 J9 CHEM PHYS LETT JI Chem. Phys. Lett. PD JUN 2 PY 2000 VL 322 IS 6 BP 472 EP 476 DI 10.1016/S0009-2614(00)00454-1 PG 5 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 320BK UT WOS:000087381000004 ER PT J AU Sander, LC Sharpless, KE Pursch, M AF Sander, LC Sharpless, KE Pursch, M TI C-30 stationary phases for the analysis of food by liquid chromatography SO JOURNAL OF CHROMATOGRAPHY A LA English DT Review DE stationary phase, LC; food analysis; reviews; carotenoids; retinoids; tocopherols; vitamins; carotenes ID POLYCYCLIC AROMATIC-HYDROCARBONS; PRESSURE CHEMICAL-IONIZATION; SOLID-STATE NMR; REVERSED-PHASE; CAROTENOID ISOMERS; MASS-SPECTROMETRY; BONDED-PHASE; HUMAN SERUM; ZEAXANTHIN STEREOISOMERS; COLUMN SELECTIVITY AB The introduction of a polymeric C-30 liquid chromatographic column by Sander et al. [Anal. Chem., 66 (1994) 1667] designed for the separation of carotenoid isomers, has led to the development of improved analytical methods for these compounds. Subsequent commercial availability of polymerically bonded C-30 columns has facilitated these advances, and applications to a wide variety of separation problems with biological samples have been described. This report provides a comprehensive review of applications of polymeric C-30 columns, utilized in the determination of carotenoids, retinoids, and other nutrients and related compounds in complex, natural-matrix samples. (C) 2000 Published by Elsevier Science B.V. C1 NIST, Div Analyt Chem, Gaithersburg, MD 20899 USA. RP Sander, LC (reprint author), NIST, Div Analyt Chem, Gaithersburg, MD 20899 USA. OI Sharpless, Katherine/0000-0001-6569-198X NR 74 TC 118 Z9 123 U1 0 U2 18 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 JUN 2 PY 2000 VL 880 IS 1-2 BP 189 EP 202 DI 10.1016/S0021-9673(00)00121-7 PG 14 WC Biochemical Research Methods; Chemistry, Analytical SC Biochemistry & Molecular Biology; Chemistry GA 324ED UT WOS:000087608100014 PM 10890520 ER PT J AU Burkholder, JB Knight, G Orlando, JJ AF Burkholder, JB Knight, G Orlando, JJ TI UV absorption spectrum of BrOCl SO JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY A-CHEMISTRY LA English DT Article DE UV absorption spectrum; BrOCl; cross section ID AB-INITIO; PHOTOLYSIS; CL2O; HOBR; BR2O AB The UV absorption cross sections for BrOCl in the gas phase have been measured over the wavelength range 230-390 nm. Absorption measurements were made at 298 K using a 100 cm long absorption cell and a diode array spectrometer. BrOCl was generated in the gas phase by exposing a BrCl/Cl-2/Br-2 gas mixture to solid HgO. The BrOCl absorption spectrum showed peaks at 272 (2.00x10(-18) cm(2) per molecule) and 320 nm (0.574x10(-18) cm(2) per molecule). Absorption cross sections were determined by mass balance following the decomposition of the gas mixture. (C) 2000 Elsevier Science S.A. All rights reserved. C1 NOAA, Aeron Lab, Boulder, CO 80303 USA. Univ Colorado, NOAA, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. Natl Ctr Atmospher Res, Div Atmospher Chem, Boulder, CO 80303 USA. RP Burkholder, JB (reprint author), NOAA, Aeron Lab, 325 Broadway,R-AL2, Boulder, CO 80303 USA. RI Burkholder, James/H-4914-2013 NR 14 TC 3 Z9 3 U1 0 U2 1 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 1010-6030 J9 J PHOTOCH PHOTOBIO A JI J. Photochem. Photobiol. A-Chem. PD JUN 2 PY 2000 VL 134 IS 1-2 BP 133 EP 137 DI 10.1016/S1010-6030(00)00261-6 PG 5 WC Chemistry, Physical SC Chemistry GA 320GA UT WOS:000087392400017 ER PT J AU Ladner, JE Reddy, P Davis, A Tordova, M Howard, AJ Gilliland, GL AF Ladner, JE Reddy, P Davis, A Tordova, M Howard, AJ Gilliland, GL TI The 1.30 angstrom resolution structure of the Bacillus subtilis chorismate mutase catalytic homotrimer SO ACTA CRYSTALLOGRAPHICA SECTION D-BIOLOGICAL CRYSTALLOGRAPHY LA English DT Article ID TRANSITION-STATE ANALOG; ESCHERICHIA-COLI; CRYSTAL-STRUCTURE; PREPHENATE; MECHANISM; REARRANGEMENT; REFINEMENT; PROGRAM; CRYSTALLOGRAPHY; COMPLEXES AB The crystal structure of the Bacillus subtilis chorismate mutase, an enzyme of the aromatic amino acids biosynthetic pathway, was determined to 1.30 Angstrom resolution. The structure of the homotrimer was determined by molecular replacement using orthorhombic crystals of space group P2(1)2(1)2(1) with unit-cell parameters a = 52.2, b = 83.8, c = 86.0 Angstrom. The ABC trimer of the monoclinic crystal structure [Chook et al. (1994), J. Mol. Biol. 240, 476-500] was used as the starting model. The final coordinates are composed of three complete polypeptide chains of 127 amino-acid residues. In addition, there are nine sulfate ions, five glycerol molecules and 424 water molecules clearly visible in the structure. This structure was refined with aniosotropic temperature factors, has excellent geometry and a crystallographic R factor of 0.169 with an R-free of 0.236. The three active sites of the macromolecule are at the subunit interfaces, with residues from two subunits contributing to each site. This orthorhombic crystal form was grown using ammonium sulfate as the precipitant; glycerol was used as a cryoprotectant during data collection. A glycerol molecule and sulfate ion in each of the active sites was found mimicking a transition-state analog. In this structure, the C-terminal tails of the subunits of the trimer are hydrogen bonded to residues of the active site of neighboring trimers in the crystal and thus cross-link the molecules in the crystal lattice. C1 Natl Inst Stand & Technol, Ctr Adv Res Biotechnol, Rockville, MD 20850 USA. Univ Maryland, Inst Biotechnol, Rockville, MD 20850 USA. Natl Inst Stand & Technol, Div Biotechnol, Gaithersburg, MD 20899 USA. IIT, Biol Chem & Phys Sci Dept, Chicago, IL 60616 USA. RP Gilliland, GL (reprint author), Natl Inst Stand & Technol, Ctr Adv Res Biotechnol, 9600 Gudelsky Dr, Rockville, MD 20850 USA. RI ID, IMCACAT/D-5867-2014 NR 38 TC 28 Z9 29 U1 0 U2 2 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0907-4449 J9 ACTA CRYSTALLOGR D JI Acta Crystallogr. Sect. D-Biol. Crystallogr. PD JUN PY 2000 VL 56 BP 673 EP 683 DI 10.1107/S0907444900004625 PN 6 PG 11 WC Biochemical Research Methods; Biochemistry & Molecular Biology; Biophysics; Crystallography SC Biochemistry & Molecular Biology; Biophysics; Crystallography GA 315VT UT WOS:000087134200001 PM 10818343 ER PT J AU Widmann, JF Charagundla, SR Presser, C Yang, GL Leigh, SD AF Widmann, JF Charagundla, SR Presser, C Yang, GL Leigh, SD TI A correction method for spray intensity measurements obtained via phase Doppler interferometry SO AEROSOL SCIENCE AND TECHNOLOGY LA English DT Article ID ATOMIZER AB A phase Doppler interferometer (PDI) was used to measure the intensity (i.e., the expected number of droplets measured per unit time) of a swirling methanol spray flame. Gaps observed in the data, which have been previously reported (McDonell and Samuelsen 1995), correspond to periods where the PDI was inactive. The intensity of the spray as a function of position within the flame was determined from the distribution of interarrival times (time between subsequent droplets entering the probe volume of the PDI), and a statistical simulation was developed to correct for the regularly occurring intervals in which the PDI does not accept data. The duration of this dead time was determined to be similar to 5.2 ms for all points in the flame for which data were collected, The intensity of the spray varied by over two orders of magnitude throughout the name. A statistical model is presented to correct for the observed behavior of the PDI, and the good agreement between the simulations and the experimental data indicate that the spray can be adequately modeled by Poisson processes. C1 Natl Inst Stand & Technol, Chem Sci & Technol Lab, Gaithersburg, MD 20899 USA. Natl Inst Stand & Technol, Informat Technol Lab, Gaithersburg, MD 20899 USA. RP Widmann, JF (reprint author), Natl Inst Stand & Technol, Chem Sci & Technol Lab, Gaithersburg, MD 20899 USA. NR 19 TC 3 Z9 3 U1 0 U2 0 PU TAYLOR & FRANCIS INC PI PHILADELPHIA PA 325 CHESTNUT ST, SUITE 800, PHILADELPHIA, PA 19106 USA SN 0278-6826 J9 AEROSOL SCI TECH JI Aerosol Sci. Technol. PD JUN PY 2000 VL 32 IS 6 BP 584 EP 601 DI 10.1080/027868200303498 PG 18 WC Engineering, Chemical; Engineering, Mechanical; Environmental Sciences; Meteorology & Atmospheric Sciences SC Engineering; Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA 318XM UT WOS:000087310000006 ER PT J AU Mazzotti, D De Natale, P Giusfredi, G Fort, C Mitchell, JA Hollberg, LW AF Mazzotti, D De Natale, P Giusfredi, G Fort, C Mitchell, JA Hollberg, LW TI Difference-frequency generation in PPLN at 4.25 mu m: an analysis of sensitivity limits for DFG spectrometers SO APPLIED PHYSICS B-LASERS AND OPTICS LA English DT Article ID TRACE-GAS-DETECTION; DIODE-LASER; WAVELENGTH; AMPLIFIER; POWER; FIBER AB We report difference-frequency generation (DFG) in periodically poled lithium niobate (PPLN) around 4.25 mu m using a cw Nd:YAG and an injection-locked diode laser. This system provides a narrow linewidth source at 4.25 mu m with near-shot-noise-limited operation. A conversion efficiency close to the theoretical limit is obtained. Detection of CO2 absorption spectra is demonstrated and further improvements and applications to high sensitivity spectroscopy are discussed. C1 Ist Nazl Ott, I-50125 Florence, Italy. Univ Florence, Dept Phys, I-50125 Florence, Italy. European Lab Nonlinear Spect, LENS, I-50125 Florence, Italy. INFM, I-50125 Florence, Italy. Natl Inst Stand & Technol, Boulder, CO 80303 USA. RP Mazzotti, D (reprint author), Ist Nazl Ott, Largo Fermi 6, I-50125 Florence, Italy. RI Mazzotti, Davide/D-1071-2010; Giusfredi, Giovanni/I-6961-2013; OI Mazzotti, Davide/0000-0003-2047-1611; FORT, Chiara/0000-0001-8817-3077; De Natale, Paolo/0000-0002-3308-8569 NR 14 TC 30 Z9 31 U1 0 U2 9 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0946-2171 J9 APPL PHYS B-LASERS O JI Appl. Phys. B-Lasers Opt. PD JUN PY 2000 VL 70 IS 6 BP 747 EP 750 DI 10.1007/s003400000263 PG 4 WC Optics; Physics, Applied SC Optics; Physics GA 322JW UT WOS:000087507300002 ER PT J AU Shearer, KD AF Shearer, KD TI Experimental design, statistical analysis and modelling of dietary nutrient requirement studies for fish: a critical review SO AQUACULTURE NUTRITION LA English DT Article DE experimental design; modelling; requirements; statistical analysis ID TROUT ONCORHYNCHUS-MYKISS; RAINBOW-TROUT; NUTRITIONAL-REQUIREMENTS; PROTEIN REQUIREMENT; PENAEUS-VANNAMEI; RESPONSE CURVES; GROWTH; EFFICIENCY; RATS AB A limited survey of published reports on dietary nutrient requirement estimates for fish (three journals, 46 papers) indicates that broken-line analysis and analysis of variance (ANOVA) are often used to estimate nutrient requirements from dose-response data. The application of regression models using published treatment mean values to re-evaluate estimates was possible using 33 of these reports. Re-evaluation suggests that the broken-line method and ANOVA frequently underestimate the requirement. Regression produced estimates that averaged approximately twice, but were up to five times the published requirement. Additional problems that prevented re-evaluation or produced errors in the original estimates were: failure to include nutrient levels high enough to produce a maximum response, failure to space nutrient input levels closely enough to adequately model the dose-response relationship, an apparent failure to screen data before analysis, and insufficient model diagnosis. Examples from the literature are presented to illustrate how design, method of analysis and the choice of model affect the requirement estimate. The effects of measurement frequency and the experiment duration on the resulting requirement estimate are discussed. A set of protocols is presented to help improve nutrient requirement estimates. C1 NOAA, Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, Seattle, WA 98112 USA. RP Shearer, KD (reprint author), NOAA, Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, 2725 Montlake Blvd E, Seattle, WA 98112 USA. NR 55 TC 133 Z9 141 U1 2 U2 16 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD OX2 0NE, OXON, ENGLAND SN 1353-5773 J9 AQUACULT NUTR JI Aquac. Nutr. PD JUN PY 2000 VL 6 IS 2 BP 91 EP 102 PG 12 WC Fisheries SC Fisheries GA 323GD UT WOS:000087556600004 ER PT J AU Storebakken, T Shearer, KD Roem, AJ AF Storebakken, T Shearer, KD Roem, AJ TI Growth, uptake and retention of nitrogen and phosphorus, and absorption of other minerals in Atlantic salmon Salmo salar fed diets with fish meal and soy-protein concentrate as the main sources of protein SO AQUACULTURE NUTRITION LA English DT Article DE Atlantic salmon (Salmo salar); availability; calcium; digestibility; fish meal; magnesium; phosphorus; protein; retention; soy-protein concentrate; zinc ID TROUT ONCORHYNCHUS-MYKISS; RAINBOW-TROUT; GASTROINTESTINAL-TRACT; SOYBEAN PRODUCTS; FRESH-WATER; PHYTIC ACID; DIGESTIBILITY; GAIRDNERI; ZINC; AVAILABILITY AB An experiment with 0.2-kg Atlantic salmon, Salmo salar in saltwater was conducted to determine if the fish could grow normally, and maintain normal nitrogen (N) and mineral balance when fed a diet with the majority of the protein (75%) derived from soy-protein concentrate (SPC). The two diets contained 50% SPC and 15% fish meal (FM) or 60% FM as the sources of protein. No calcium phosphate was added to the diets in order to assess the availability of P from the ingredients. A second aim was to investigate if whole-body concentrations of essential elements and growth were related in individual salmon. Growth (SGR=0.88-0.89) was similar in salmon fed the two diets, and the fish nearly doubled their body weights during the 84 days of feeding. Feed conversion was more efficient for the FM diet (0.81 kg intake kg(-1) gain) than for the SPC diet (0.89 kg kg(-1)). The intake of N was similar, faecal loss of N was lower, while the metabolic N excretion was greater in the fish fed the FM than the SPC diet. This resulted in a total excretion of 35.4 g N kg(-1) gain for the salmon fed the FM diet and 35.5 g N for the fish fed the SPC diet. Both the intake, faecal and metabolic excretion of P were higher in the fish fed the FM diet than the SPC diet, resulting in a total excretion of 10.5 g P kg(-1) gain for the FM diet and 7.2 g P for the SPC diet. Whole-body concentrations of Ca, Mg, P and Zn were lower in the fish fed the SPC diet, while the Ca-P ratio was decreased, both when compared with the fish at the start of the experiment, and the fish fed the FM diet. The differences in elemental composition were ascribed to a combination of reduced availability of elements due to phytic acid and lower concentration of elements in the SPC than in the FM. No reduction in growth of individual fish, which could be ascribed to reduced availability of essential elements, was seen. C1 Inst Aquaculture Res AS, N-6600 Sunndalsora, Norway. NOAA, Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, Seattle, WA 98112 USA. Nutreco Aquaculture Res Ctr, Stavanger, Norway. RP Storebakken, T (reprint author), Inst Aquaculture Res AS, N-6600 Sunndalsora, Norway. RI storebakken, trond/E-8050-2011 OI storebakken, trond/0000-0002-4525-2098 NR 31 TC 60 Z9 66 U1 0 U2 23 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD OX2 0NE, OXON, ENGLAND SN 1353-5773 J9 AQUACULT NUTR JI Aquac. Nutr. PD JUN PY 2000 VL 6 IS 2 BP 103 EP 108 PG 6 WC Fisheries SC Fisheries GA 323GD UT WOS:000087556600005 ER PT J AU Gutman, G Csiszar, I Romanov, P AF Gutman, G Csiszar, I Romanov, P TI Using NOAA/AVHRR products to monitor El Nino impacts: Focus on Indonesia in 1997-98 SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article ID HIGH-RESOLUTION RADIOMETER; SOUTHERN OSCILLATION; LAND; SATELLITE; AVHRR; FIRE; LIMITATIONS; DATASET; AEROSOL; AMERICA AB The development of the Fl Nino-Southern Oscillation (ENSO) in 1997-98, the most intense in this century, has been monitored by space- and ground-based observations. In this study, the authors present the signatures of ENSO impacts on the surface-atmosphere system, as detected in satellite products that are routinely derived at NOAA from measurements by a single instrument on board NOAA polar-orbiting satellites-the Advanced Very High Resolution Radiometer (AVHRR). The Indonesian archipelago was selected to demonstrate how AVHRR products can be synergistically used to monitor interannual variability, such as caused by ENSO, on regional and global scales. The authors examined month-to-month changes in surface-atmosphere conditions over the region during July 1997-June 1998. The major ENSO impact over the Indonesian archipelago was a prolonged dry period with anomalously low amounts of cloud, precipitation, and water vapor. The net effect of these changes was a significant increase in the absorbed shortwave and outgoing longwave radiation fluxes. ENSO-induced drought coincided with the slash-and-burn agricultural season, which resulted in persistent fires and smoke from biomass burning, covering larger areas, producing more smoke, remaining longer than during most dry seasons, and causing health hazards for millions of people in Southeast Asia. Analysis of the impact of fires on cloud microphysics confirms earlier suggestions that the effective cloud droplet size decreases due to smoke aerosols and cloud reflectivity increases due to higher concentration of small droplets. Analysis of areas with active fires showed a decrease in both surface albedo and fractional green vegetation as a result of intensive burning. C1 NOAA, NESDIS, Off Res & Applicat, Camp Springs, MD 20748 USA. Colorado State Univ, Cooperat Inst Res Atmosphere, Ft Collins, CO 80523 USA. RP Csiszar, I (reprint author), NOAA, NESDIS, Off Res & Applicat, E-RA1,WWB 712,5200 Auth Rd, Camp Springs, MD 20748 USA. EM icsiszar@nesdis.noaa.gov RI Romanov, Peter/F-5622-2010; Csiszar, Ivan/D-2396-2010 OI Romanov, Peter/0000-0002-2153-8307; NR 42 TC 36 Z9 37 U1 0 U2 6 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 JUN PY 2000 VL 81 IS 6 BP 1189 EP 1205 DI 10.1175/1520-0477(2000)081<1189:UNPTME>2.3.CO;2 PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 319FF UT WOS:000087330300001 ER PT J AU Kidder, SQ Goldberg, MD Zehr, RM DeMaria, M Purdom, JFW Velden, CS Grody, NC Kusselson, SJ AF Kidder, SQ Goldberg, MD Zehr, RM DeMaria, M Purdom, JFW Velden, CS Grody, NC Kusselson, SJ TI Satellite analysis of tropical cyclones using the Advanced Microwave Sounding Unit (AMSU) SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article ID INTENSITY; RAINFALL; PRECIPITATION; RADIOMETER; RETRIEVAL; IMAGERY; WINDS AB The first Advanced Microwave Sounding Unit (AMSU) was launched aboard the NOAA-15 satellite on 13 May 1998. The AMSU is well suited for the observation of tropical cyclones because its measurements are not significantly affected by the ice clouds that cover tropical storms. In this paper, the following are presented: 1) upper-tropospheric thermal anomalies in tropical cyclones retrieved from AMSU data, 2) the correlation of maximum temperature anomalies with maximum wind speed and central pressure, 3) winds calculated from the temperature anomaly field, 4) comparison of AMSU data with GOES and AVHRR imagery, and 5) tropical cyclone rainfall potential. The AMSU data appear to offer substantial opportunities for improvement in tropical cyclone analysis and forecasting. C1 Colorado State Univ, Cooperat Inst Res Atmosphere, Ft Collins, CO 80523 USA. NOAA, Natl Environm Satellite Data & Informat Serv, ORA, Washington, DC 20233 USA. NOAA, NESDIS, RAMM Team, Ft Collins, CO USA. Univ Wisconsin, CIMSS, Madison, WI USA. NOAA, Natl Environm Satellite Data & Informat Serv, Microwave Sensing Grp, Washington, DC 20233 USA. NOAA, Natl Environm Satellite Data & Informat Serv, SAB, Washington, DC 20233 USA. RP Kidder, SQ (reprint author), Colorado State Univ, Cooperat Inst Res Atmosphere, Foothills Campus, Ft Collins, CO 80523 USA. RI Goldberg, Mitch/F-5589-2010; DeMaria, Mark/F-5583-2010 NR 34 TC 86 Z9 110 U1 1 U2 7 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 JUN PY 2000 VL 81 IS 6 BP 1241 EP 1259 DI 10.1175/1520-0477(2000)081<1241:SAOTCU>2.3.CO;2 PG 19 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 319FF UT WOS:000087330300004 ER PT J AU Barnston, AG He, YX Unger, DA AF Barnston, AG He, YX Unger, DA TI A forecast product that maximizes utility for state-of-the-art seasonal climate prediction SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article ID EL-NINO; TEMPERATURE; IMPACTS; WEATHER AB The prediction of seasonal climate anomalies at useful lead times often involves an unfavorable signal-to-noise ratio. The forecasts, while consequently tending to have modest skill, nonetheless have significant utility when packaged in ways to which users can relate and respond appropriately. This paper presents a reasonable but unprecedented manner in which to issue seasonal climate forecasts and illustrates how implied "tilts of the odds" of the forecasted climate may be used beneficially by technical as well as nontechnical clients. C1 NOAA, NWS, NCEP, Climate Predict Ctr, Camp Springs, MD 20746 USA. RP Barnston, AG (reprint author), NOAA, NWS, NCEP, Climate Predict Ctr, W-NP5,World Weather Bldg,Room 604,5200 Auth Rd, Camp Springs, MD 20746 USA. NR 16 TC 30 Z9 30 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 JUN PY 2000 VL 81 IS 6 BP 1271 EP 1279 DI 10.1175/1520-0477(2000)081<1271:AFPTMU>2.3.CO;2 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 319FF UT WOS:000087330300006 ER PT J AU Auciello, EP AF Auciello, EP TI First Northeast Regional Operational Workshop SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Editorial Material AB The First Northeast Regional Operational Workshop, focusing on hydrometeorology in the northeastern United States, was held 21-23 September 1999 in Albany, New York. Sessions in local and mesoscale modeling, fake-effect snow, hydrology, heavy precipitation forecasting and events, operational techniques, and northeast severe convection were presented. A summary of workshop presentations is provided. C1 NOAA, Natl Weather Serv, Ctr Environm Sci & Technol Management, Albany, NY 12203 USA. RP Auciello, EP (reprint author), NOAA, Natl Weather Serv, Ctr Environm Sci & Technol Management, 251 Fuller Rd, Albany, NY 12203 USA. NR 0 TC 0 Z9 0 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 JUN PY 2000 VL 81 IS 6 BP 1327 EP 1331 DI 10.1175/1520-0477(2000)081<1327:MSFNRO>2.3.CO;2 PG 5 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 319FF UT WOS:000087330300010 ER PT J AU Bell, GD Halpert, MS Schnell, RC Higgins, RW Lawrimore, J Kousky, VE Tinker, R Thiaw, W Chelliah, M Artusa, A AF Bell, GD Halpert, MS Schnell, RC Higgins, RW Lawrimore, J Kousky, VE Tinker, R Thiaw, W Chelliah, M Artusa, A TI Climate assessment for 1999 SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article ID SOUTHERN OSCILLATION; NORTHERN-HEMISPHERE; CYCLONE FORMATION; CARBON-MONOXIDE; PATTERNS; MONSOON; TRENDS; OZONE; HALOCARBONS; VARIABILITY AB The global climate during 1999 was impacted by Pacific cold episode (La Nina) conditions throughout the year, which resulted in regional precipitation and atmospheric circulation patterns across the Pacific Ocean and the Americas that are generally consistent with those observed during past cold episodes. The primary La Nina-related precipitation anomalies included 1) increased rainfall across Indonesia, and a nearly complete disappearance of rainfall across the east-central and eastern equatorial Pacific; 2) above-normal rains across northwestern and northern Australia; 3) increased monsoon rains across the Sahel region of western Africa; 4) above-average rains over southeastern Africa, 5) above-average rains over the Caribbean Sea and portions of Central America, and 6) below-average rains in southeastern South America. The La Nina also contributed to persistent cyclonic circulation anomalies in the subtropics of both hemispheres, which Banked the area of suppressed convective activity over the eastern half of the equatorial Pacific. In the Northern Hemisphere this anomaly feature contributed to a pronounced westward retraction of the wintertime East Asian jet stream, which subsequently impacted precipitation and storm patterns across the eastern North Pacific and western North America. The La Nina-related pattern of tropical rainfall also contributed to a very persistent pattern of anticyclonic circulation anomalies in the middle latitude of both hemispheres, extending from the eastern Pacific across the Atlantic and Africa eastward to Australasia. This anomaly pattern was associated with an active Atlantic hurricane season, an inactive eastern North Pacific hurricane season, above-average rains in the African Sahel, and an overall amplification of the entire southeast Asian summer monsoon complex. The active 1999 North Atlantic hurricane season featured 12 named storms, 8 of which became hurricanes, and 5 of which became intense hurricanes. The peak of activity during mid-August-October was accompanied by low vertical wind shear across the central and western Atlantic, along with both a favorable structure and location of the African easterly jet. In contrast, only 9 tropical storms formed over the eastern North Pacific during the year, making it one of the most inactive years for that region in the historical record. This relative inactivity was linked to a persistent pattern of high vertical wind shear that covered much of the main development region of the eastern North Pacific. Other regional aspects of the short-term climate included: 1) above-average wintertime precipitation and increased storminess in the Pacific Northwest, United States; 2) above-average monsoonal rainfall across the southwestern United States; 3) drought over the northeastern quadrant of the United States during April-mid-August; 4) hurricane-related flooding in the Carolinas during September; 5) drought over the south-central United States during July-November; 6) below-average rainfall in the Hawaiian Islands throughout the year, with long-term dryness affecting some parts of the islands since October 1997; 7) a continuation of long-term drought conditions in southeastern Australia, with most of Victoria experiencing below-average rainfall since late 1996; and 8) above-average rainfall in central China during April-August. Global annual mean surface temperatures during 1999 for land and marine areas were 0.41 degrees C above the 1880-1998 long-term mean, making it the fifth warmest year in the record. However, significant cooling was evident in the Tropics during 1999 in association with a continuation of La Nina conditions. In contrast, temperatures in both the Northern Hemisphere and Southern Hemisphere extratropics were the second wannest in the historical record during 1999, and only slightly below the record 1998 anomalies. The areal extent of the Antarctic ozone hole remained near record levels during 1999. The ozone hole also lasted longer than has been observed in past years. C1 NOAA, Natl Weather Serv, NCEP, Climate Predict Ctr, Washington, DC 20233 USA. NOAA, Climate Monitoring & Diagnost Lab, Boulder, CO 80303 USA. NOAA, Natl Climate Data Ctr, Asheville, NC USA. RP Halpert, MS (reprint author), NOAA, NCEP, Climate Predict Ctr, W-NP52,NSC Rm 605,5200 Auth Rd, Camp Springs, MD 20746 USA. NR 45 TC 151 Z9 162 U1 3 U2 16 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 JUN PY 2000 VL 81 IS 6 BP S1 EP S50 DI 10.1175/1520-0477(2000)81[s1:CAF]2.0.CO;2 PG 50 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 319FF UT WOS:000087330300021 ER PT J AU Eanes, ED Hailer, AW AF Eanes, ED Hailer, AW TI Anionic effects on the size and shape of apatite crystals grown from physiological solutions SO CALCIFIED TISSUE INTERNATIONAL LA English DT Article DE apatite; albumin; calcification; citrate; mineralization ID CONSTANT COMPOSITION; BONE TISSUE; OSTEOGENESIS IMPERFECTA; ELECTRON-DIFFRACTION; DISSOLVED ALBUMIN; ORGANIC MATRIX; SEEDED GROWTH; HYDROXYAPATITE; CRYSTALLIZATION; COLLAGEN AB Comparatively little is known of the role tissue fluid electrolytes have in establishing the size and shape of apatite crystals deposited in skeletal tissues. In vitro accretion experiments using synthetic apatite seed crystals comparable in size to bone apatite were performed to assess the extent to which these crystalline features may be affected by direct electrolyte/mineral interactions. A constant composition method was used to maintain the accretion reactions under physiological-like solution conditions (1.33 mmol/liter Ca2+, 1.0 mmol/liter total inorganic phosphate, (0 or 26) mmol/liter carbonate, 270 mmol/kg osmolality, pH 7.4, 37 degrees C). When the mass of the new accretions equaled the initial seed mass, the solids were harvested and the net change in crystal size resulting from the new accretions was assessed by X-ray diffraction line-broadening analysis. All the electrolytes examined in this study inhibited the accretion rate. The order of effectiveness was phosvitin > polyaspartate approximate to polyglutamate > 1-hydroxyethylidene-1,1-bisphosphonate (HEBP) > bovine serum albumin (BSA) > citrate. Citrate and BSA also reduced the mean crystal size of the harvested solids compared with those harvested in the absence of added electrolyte, a finding that suggests that citrate and BSA suppressed growth of the seed crystals in favor of the proliferation of new smaller crystals. In contrast, a net increase in size following accretion compared with controls suggests that the other more strongly inhibiting electrolytes stimulated growth of the primary seed crystals and/or of the secondary crystals. These size changes, however, were anisotropic, with the anions effecting primarily increases in crystal width/thickness rather than in length. The effects were also more pronounced in the presence of carbonate. Our findings suggest that the strength of the interaction with the crystal surface may be relatively more important than molecular size or conformational complexity in establishing the effect that electrolytes have on apatite growth and proliferation. The results also suggest that adsorbed electrolytes may be a significant factor in controlling the size of apatite crystals in skeletal tissues by inducing proliferation of new crystals and/or affecting crystal shape by selectively modifying growth of the lateral dimensions. C1 Natl Inst Stand & Technol, Natl Inst Dent & Craniofacial Res, Craniofacial & Skeletal Dis Branch, Res Associate Program, Gaithersburg, MD 20899 USA. RP Eanes, ED (reprint author), Natl Inst Stand & Technol, Natl Inst Dent & Craniofacial Res, Craniofacial & Skeletal Dis Branch, Res Associate Program, 100 Bur Dr,Stop 8545, Gaithersburg, MD 20899 USA. NR 38 TC 16 Z9 16 U1 2 U2 9 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0171-967X J9 CALCIFIED TISSUE INT JI Calcif. Tissue Int. PD JUN PY 2000 VL 66 IS 6 BP 449 EP 455 DI 10.1007/s002230010090 PG 7 WC Endocrinology & Metabolism SC Endocrinology & Metabolism GA 317VR UT WOS:000087248100010 PM 10821882 ER PT J AU Abdulagatov, IM Dvoryanchikov, VI Kamalov, AN Abramova, EG Abdurashidova, MA AF Abdulagatov, IM Dvoryanchikov, VI Kamalov, AN Abramova, EG Abdurashidova, MA TI One- and two-phase isochoric heat capacity measurements of aqueous solution of NaCl near the critical point of pure water SO CANADIAN JOURNAL OF CHEMICAL ENGINEERING LA English DT Article DE aqueous sodium chloride solution; critical point; crossover equation of state; isochoric heat capacity; supercritical fluid ID CONSTANT VOLUME; CRITICAL-BEHAVIOR; CRITICAL REGION; IONIC FLUIDS; DILUTE NACL; CROSSOVER; MIXTURES; EQUATION; STATE; H2O AB Isochoric heat capacities of H2O+NaCl solutions (0.0031 and 0.0063 mole fraction of NaCl) were measured with a high temperature and high pressure adiabatic calorimeter near the sub-critical and near the supercritical point of pure water. Temperatures ranged from 361 to 677 K. Measurements were made at six densities, namely: 367.07 and 485.59 kg.m(-3) for x = 0.0031 mol fraction of NaCl and 388.65, 560.03, 607.05, and 973.70 kg.m(-3) for x = 0.0063 mol fraction of NaCl. Measurements were conducted in the two- and one-phase regions including near phase transition temperatures T-S(rho). The phase transition temperatures T-S(rho) and saturated isochoric heat capacity values C-VX have been determined for each isochore. The uncertainty in heat capacity measurements is estimated to be 3.5% to 4.5% near the phase transition and critical points. Present and previous results of heat capacity measurements were compared with predictions from the crossover (CREOS) and Pitzer-Tanger-Hovey equations of state (PTH EOS). Our previous heat capacity measurements were found to deviate systematically from crossover-model predictions. The present results show good agreement with the crossover model for the composition x = 0.0031 mol fraction. C1 Russian Acad Sci, Dagestan Sci Ctr, Inst Geothermal Res, Makhachkala 367030, Dagestan, Russia. RP Abdulagatov, IM (reprint author), Natl Inst Stand & Technol, Phys & Chem Properties Div, 325 Broadway, Boulder, CO 80303 USA. NR 42 TC 0 Z9 0 U1 0 U2 0 PU CANADIAN SOC CHEMICAL ENGINEERING PI OTTAWA PA 130 SLATER ST, STE 550, OTTAWA, ONTARIO K1P 6E2, CANADA SN 0008-4034 J9 CAN J CHEM ENG JI Can. J. Chem. Eng. PD JUN PY 2000 VL 78 IS 3 BP 547 EP 556 PG 10 WC Engineering, Chemical SC Engineering GA 341WJ UT WOS:000088613700014 ER PT J AU Friedland, KD Reddin, DG AF Friedland, KD Reddin, DG TI Growth patterns of Labrador Sea Atlantic salmon postsmolts and the temporal scale of recruitment synchrony for North American salmon stocks SO CANADIAN JOURNAL OF FISHERIES AND AQUATIC SCIENCES LA English DT Article ID ONCORHYNCHUS-KISUTCH; MARINE SURVIVAL; SALAR; FISH; MATURATION; NURSERY; AREA; SIZE AB We measured postsmolt growth patterns from scales of Atlantic salmon postsmolts captured in the Labrador Sea and adult returns from stocks at the southern end of the range of salmon in North America. Because Labrador Sea postsmolts are believed to represent the juvenile nursery for the entire stock complex, the growth variation for southern stocks may yield insights on the time scale of stock mixing during the postsmolt year. Circuli spacing patterns were extracted from the scales of 1525 salmon for 3 smolt years. For 2 of the 3 years, growth trajectories for fish from the southern stocks intersected the trajectories for Labrador Sea postsmolts after 4-5 circuli pairs. The time that it takes to deposit a circulus during the spring and summer seasons suggests that distribution patterns for regional groups begin to overlap or stocks begin to experience similar environmental conditions by June or July of the postsmolt year, or 1 to 2 months after their migration to sea. In some years, however, it would appear that this mixing does not occur until fall. These data provide the first indication of the time scale of events during the postsmolt year that regional influences may be acting on stocks to produce synchronous recruitment. C1 Univ Massachusetts, UMass NOAA CMER Program, Amherst, MA 01003 USA. Fisheries & Oceans Canada, Sci Branch, St Johns, NF A1C 5X1, Canada. RP Friedland, KD (reprint author), Univ Massachusetts, UMass NOAA CMER Program, Blaisdell House, Amherst, MA 01003 USA. NR 33 TC 11 Z9 13 U1 0 U2 4 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 JUN PY 2000 VL 57 IS 6 BP 1181 EP 1189 DI 10.1139/cjfas-57-6-1181 PG 9 WC Fisheries; Marine & Freshwater Biology SC Fisheries; Marine & Freshwater Biology GA 325YC UT WOS:000087703800008 ER PT J AU Sigler, MF AF Sigler, MF TI Abundance estimation and capture of sablefish (Anoplopoma fimbria) by longline gear SO CANADIAN JOURNAL OF FISHERIES AND AQUATIC SCIENCES LA English DT Article ID GADUS-MORHUA; BAIT; FISH; RESPONSES; BEHAVIOR; COD AB Longline surveys in Alaska measure sablefish (Anoplopoma fimbria) relative abundance and are the primary information source used for abundance and quota estimation. Hook timer, on-bottom (soak) time, hook density, hook pattern, bait type, and bait condition experiments and mathematical models were used to evaluate the performance of the longline surveys for estimating sablefish relative abundance. The rate that sablefish encountered the longline gear decreased with on-bottom time independently of sablefish density in the sampled area. Sablefish were adept at locating available baits, even when few remained. The decrease in encounter rate appears related to odor concentration at the leading edge of the odor plume. The ability to locate baits, even when few remain, differs from previous models of fish capture by longline in which the probability that a fish located a bait was proportional to the number of available baits. Decreased encounter rate and the ability to locate baits efficiently imply that longline catch rates likely provide an accurate index of fish abundance if the on-bottom time is long enough to cover the period when most fish encounter the gear and the initial bait density is high enough that baits remain available throughout the soak; the weak link between catch rate and abundance is the unknown extent that factors such as temperature and food availability affect the proportion of fish caught. C1 Natl Marine Fisheries Serv, NOAA, Alaska Fisheries Sci Ctr, Auke Bay Lab, Juneau, AK 99801 USA. RP Sigler, MF (reprint author), Natl Marine Fisheries Serv, NOAA, Alaska Fisheries Sci Ctr, Auke Bay Lab, 11305 Glacier Highway, Juneau, AK 99801 USA. NR 26 TC 21 Z9 22 U1 2 U2 6 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 JUN PY 2000 VL 57 IS 6 BP 1270 EP 1283 DI 10.1139/cjfas-57-6-1270 PG 14 WC Fisheries; Marine & Freshwater Biology SC Fisheries; Marine & Freshwater Biology GA 325YC UT WOS:000087703800017 ER PT J AU Holland, DS AF Holland, DS TI A bioeconomic model of marine sanctuaries on Georges Bank SO CANADIAN JOURNAL OF FISHERIES AND AQUATIC SCIENCES LA English DT Article ID FISHERIES; MANAGEMENT AB An empirically estimated fleet dynamics model for New England trawlers is integrated with spatial, age-structured models of primary groundfish species on Georges Banks, southern New England, and the Gulf of Maine. This bioeconomic model is used to explore how permanent marine sanctuaries on Georges Bank might affect catches, revenues, and spawning stock of principal groundfish species in New England. The simulations explore how the location of sanctuaries relative to major ports and their orientation relative to seasonal movement patterns of fish stocks impact their effectiveness and the distribution of benefits across groups of fishers from different ports. The simulation results also demonstrate that the impacts of sanctuaries can vary greatly across species, sometimes increasing yields for some while decreasing yields for others. While the specific results from the simulations reflect the characteristics of the New England groundfish fishery, the modeling methodology and some general conclusions are applicable to other fisheries. C1 Natl Marine Fisheries Serv, NOAA, Alaska Fisheries Sci Ctr, Seattle, WA 98115 USA. RP Holland, DS (reprint author), Natl Marine Fisheries Serv, NOAA, Alaska Fisheries Sci Ctr, 7600 Sand Point Way NE, Seattle, WA 98115 USA. OI Holland, Daniel/0000-0002-4493-859X NR 23 TC 42 Z9 42 U1 0 U2 4 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 JUN PY 2000 VL 57 IS 6 BP 1307 EP 1319 PG 13 WC Fisheries; Marine & Freshwater Biology SC Fisheries; Marine & Freshwater Biology GA 325YC UT WOS:000087703800021 ER PT J AU Bentz, DP Jensen, OM Coats, AM Glasser, FP AF Bentz, DP Jensen, OM Coats, AM Glasser, FP TI Influence of silica fume on diffusivity in cement-based materials I. Experimental and computer modeling studies on cement pastes SO CEMENT AND CONCRETE RESEARCH LA English DT Article DE cement paste; diffusion; hydration; modeling; silica fume ID MICROSTRUCTURAL MODEL; SIMULATION; MORTAR AB Experimental and computer modeling studies are applied in determining the influence of silica fume on the microstructure and diffusivity of cement paste. It is suggested that silica fume modifies the inherent nanostructure of the calcium silicate hydrate (C-S-H) gel, reducing its porosity and thus increasing its resistance to diffusion of both tritiated water and chloride ions. Because the pores in the C-S-H are extremely fine, the relative reduction in diffusion depends on the specific diffusing species. Based on the NIST cement hydration and microstructural model, for tritiated water diffusion, the reduction in the diffusivity of the gel caused by silica fume is about a factor of five. For chloride ions, when a diffusivity value 25 times lower than that used for conventional high Ca/Si ratio C-S-H is assigned to the pozzolanic lower Ca/Si ratio C-S-H, excellent agreement is obtained between experimental chloride ion diffusivity data and results generated based on the NIST model, for silica fume additions ranging from 0% to 10%. For higher addition rates, the experimentally observed reduction in diffusivity is significantly greater than that predicted from the computer models, suggesting that at these very high dosages, the nanostructure of the pozzolanic C-S-H may be even further modified. Based on the hydration model, a percolation-based explanation of the influence of silica fume on diffusivity is proposed and a set of equations relating diffusivity to capillary porosity and silica fame addition rate is developed. A 10% addition of silica fume may result in a factor of 15 or mon reduction in chloride ion diffusion and could potentially lead to a substantial increase in the service life of steel-reinforced concrete exposed to a severe environment. (C) 2000 Elsevier Science Ltd. All rights reserved. C1 Natl Inst Stand & Technol, Bldg & Fire Res Lab, Gaithersburg, MD 20899 USA. Univ Aalborg, Inst Bldg Technol & Struct Engn, Aalborg, Denmark. Univ Aberdeen, Dept Chem, Aberdeen, Scotland. RP Bentz, DP (reprint author), Natl Inst Stand & Technol, Bldg & Fire Res Lab, 100 Bur Dr Stop 8621, Gaithersburg, MD 20899 USA. RI Chen, Wei/A-5694-2010 NR 37 TC 96 Z9 104 U1 0 U2 21 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 JUN PY 2000 VL 30 IS 6 BP 953 EP 962 DI 10.1016/S0008-8846(00)00264-7 PG 10 WC Construction & Building Technology; Materials Science, Multidisciplinary SC Construction & Building Technology; Materials Science GA 342JU UT WOS:000088642100014 ER PT J AU Ferraris, C Garboczi, E Stutzman, P Winpigler, J Clifton, J AF Ferraris, C Garboczi, E Stutzman, P Winpigler, J Clifton, J TI Influence of silica fume on the stresses generated by alkali-silica reaction SO CEMENT CONCRETE AND AGGREGATES LA English DT Article; Proceedings Paper CT Symposium on Developments in Test Methods for Alkali-Silica Reaction CY DEC, 1998 CL NASHVILLE, TENNESSEE SP ASTM Comm C01 & C09 DE alkali-silica reaction; mortar; silica fume; stress measurements; stress relaxation ID CONCRETE AB Present test methods for determining the suitability of a given combination of cement and aggregates with respect to the potential for alkali-silica reaction (ASR) are based on the measurement of the expansion of the concrete/mortar under prescribed conditions. The scope of this study was to determine the influence of the addition of silica fume as a cement replacement on the stresses generated by the specimen, a parameter that could be useful for the engineer. Cylindrical specimens were placed in a frame equipped with a load cell that fixed the axial strain at approximately zero and measured the axial stress generated over time. A replacement of cement by silica fume at a dosage of 15% by mass for two different WIC ratios led to a significant decrease of the measured stress. SEM observations helped to provide a tentative explanation for the stress and expansion reduction mechanisms with the addition of silica fume. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Ferraris, C (reprint author), Natl Inst Stand & Technol, Bldg 226,Room B350, Gaithersburg, MD 20899 USA. NR 15 TC 1 Z9 1 U1 0 U2 0 PU AMER SOC TESTING MATERIALS PI W CONSHOHOCKEN PA 100 BARR HARBOR DR, W CONSHOHOCKEN, PA 19428-2959 USA SN 0149-6123 J9 CEMENT CONCRETE AGGR JI Cem. Concr. Aggreg. PD JUN PY 2000 VL 22 IS 1 BP 73 EP 78 PG 6 WC Construction & Building Technology; Materials Science, Multidisciplinary SC Construction & Building Technology; Materials Science GA 358BC UT WOS:000089536500011 ER PT J AU Kahn, SE Apple, FS Bodor, GS Panteghini, M Welch, MH Wu, AHB Dalluge, J Bunk, D Christenson, RH AF Kahn, SE Apple, FS Bodor, GS Panteghini, M Welch, MH Wu, AHB Dalluge, J Bunk, D Christenson, RH TI Standardization of cardiac troponin I assays: pilot evaluation of ten candidate reference materials. SO CLINICAL CHEMISTRY LA English DT Meeting Abstract C1 Loyola Univ, Med Ctr, Maywood, IL 60153 USA. Hennepin Cty Med Ctr, Minneapolis, MN 55415 USA. Denver Hlth Med Ctr, Denver, CO USA. Spedali Civili, I-25125 Brescia, Italy. NIST, Gaithersburg, MD 20899 USA. Hartford Hosp, Hartford, CT 06115 USA. Univ Maryland, Baltimore, MD 21201 USA. NR 0 TC 3 Z9 4 U1 0 U2 1 PU AMER ASSOC CLINICAL CHEMISTRY PI WASHINGTON PA 2101 L STREET NW, SUITE 202, WASHINGTON, DC 20037-1526 USA SN 0009-9147 J9 CLIN CHEM JI Clin. Chem. PD JUN PY 2000 VL 46 IS 6 SU S MA 340 BP A89 EP A89 PN 2 PG 1 WC Medical Laboratory Technology SC Medical Laboratory Technology GA 326GU UT WOS:000087725600342 ER PT J AU Battaglia, F McGrattan, KB Rehm, RG Baum, HR AF Battaglia, F McGrattan, KB Rehm, RG Baum, HR TI Simulating fire whirls SO COMBUSTION THEORY AND MODELLING LA English DT Article AB A numerical investigation of swirling fire plumes is pursued to understand how swirl alters the plume dynamics and combustion. One example is the 'fire whirl' which is known to arise naturally during forest fires. This buoyancy-driven fire plume entrains ambient fluid as heated gases rise. Vorticity associated with a mechanism such as wind shear can be concentrated by the fire, creating a vortex core along the axis of the plume. The result is a whirling fire. The current approach considers the relationship between buoyancy and swirl using a configuration based on fixing the heat release rate of the fire and imposing circulation. Large-eddy methodologies are used in the numerical analyses. Results indicate that the structure of the fire plume is significantly altered when angular momentum is imparted to the ambient fluid. The vertical acceleration induced by buoyancy generates strain fields which stretch out the flames as they wrap around the nominal plume centreline. The whirling fire constricts radially and stretches the plume vertically. C1 Iowa State Univ, Dept Engn Mech, Ames, IA 50011 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Battaglia, F (reprint author), Iowa State Univ, Dept Engn Mech, Ames, IA 50011 USA. RI Battaglia, Francine/E-9189-2014 OI Battaglia, Francine/0000-0002-0380-3402 NR 24 TC 27 Z9 33 U1 0 U2 12 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 1364-7830 J9 COMBUST THEOR MODEL JI Combust. Theory Model. PD JUN PY 2000 VL 4 IS 2 BP 123 EP 138 DI 10.1088/1364-7830/4/2/303 PG 16 WC Thermodynamics; Energy & Fuels; Engineering, Chemical; Mathematics, Interdisciplinary Applications SC Thermodynamics; Energy & Fuels; Engineering; Mathematics GA 327WA UT WOS:000087816000003 ER PT J AU Berger, JR Skilowitz, JL Tewary, VK AF Berger, JR Skilowitz, JL Tewary, VK TI Green's function for steady-state heat conduction in a bimaterial composite solid SO COMPUTATIONAL MECHANICS LA English DT Article ID ELEMENT; SHELLS AB The derivation of a Green's function for steady-state heat conduction in anisotropic bimaterials is presented. The Green's function is obtained through a Fourier representation to obtain both free-space, singular parts and region-dependent, regular parts. To obtain the region-dependent parts of the Green's function, the homogeneous solution is written using the virtual force method. Full details of the necessary inversion integrals are provided. The Green's function is shown to degenerate to the usual logarithmic potential for steady-state heat conduction in isotropic solids. The normal derivatives necessary for implementation of the Green's function in boundary integral equations are provided, and an example calculation of the Green's function in a quartz-copper material system is presented. C1 Colorado Sch Mines, Div Engn, Golden, CO 80401 USA. NIST, Div Mat Reliabil, Boulder, CO USA. RP Berger, JR (reprint author), Colorado Sch Mines, Div Engn, Golden, CO 80401 USA. RI Berger, John/F-5169-2010 NR 15 TC 8 Z9 8 U1 0 U2 5 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0178-7675 J9 COMPUT MECH JI Comput. Mech. PD JUN PY 2000 VL 25 IS 6 BP 627 EP 633 DI 10.1007/s004660050509 PG 7 WC Mathematics, Interdisciplinary Applications; Mechanics SC Mathematics; Mechanics GA 332ZG UT WOS:000088103800011 ER PT J AU Zhang, JZ AF Zhang, JZ TI Shipboard automated determination of trace concentrations of nitrite and nitrate in oligotrophic water by gas-segmented continuous flow analysis with a liquid waveguide capillary flow cell SO DEEP-SEA RESEARCH PART I-OCEANOGRAPHIC RESEARCH PAPERS LA English DT Article ID NANOMOLAR CONCENTRATIONS; ABSORBENCY SPECTROSCOPY; CHEMI-LUMINESCENCE; NATURAL-WATERS; LONG; SEAWATER AB Incorporation of a liquid waveguide capillary flow cell in a gas-segmented continuous flow auto-analyzer significantly enhances the sensitivity of automated colorimetric analysis. Nanomolar concentrations of nitrite and nitrate in oligotrophic surface seawater can be accurately determined. The advantages of this technique are low detection limit, high precision, and automation for rapid analysis of a large number of samples. This technique was successfully used on shipboard measurements of about 1000 seawater samples during a one-month cruise in the North Atlantic. (C) 2000 Elsevier Science Ltd. All rights reserved. C1 NOAA, Atlantic Oceanog & Meteorol Lab, Ocean Chem Div, Miami, FL 33149 USA. Univ Miami, Rosenstiel Sch Marine & Atmospher Sci, CIMAS, Miami, FL 33149 USA. RP Zhang, JZ (reprint author), NOAA, Atlantic Oceanog & Meteorol Lab, Ocean Chem Div, 4301 Rickenbacker Causeway, Miami, FL 33149 USA. EM zhang@aoml.noaa.gov RI Zhang, Jia-Zhong/B-7708-2008 OI Zhang, Jia-Zhong/0000-0002-1138-2556 NR 29 TC 54 Z9 57 U1 3 U2 12 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 JUN PY 2000 VL 47 IS 6 BP 1157 EP 1171 DI 10.1016/S0967-0637(99)00085-0 PG 15 WC Oceanography SC Oceanography GA 297LQ UT WOS:000086084700010 ER PT J AU Carls, MG Hose, JE Thomas, RE Rice, SD AF Carls, MG Hose, JE Thomas, RE Rice, SD TI Exposure of Pacific herring to weathered crude oil: Assessing effects on ova SO ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY LA English DT Article DE Pacific herring; gametes; larvae; polynuclear aromatic hydrocarbons; Exxon Valdez oil spill ID EXXON-VALDEZ OIL; PRINCE-WILLIAM-SOUND; LIFE-HISTORY STAGES; PETROLEUM-HYDROCARBONS; CLUPEA-PALLASI; ATLANTIC CROAKER; SPILL; LARVAE; ALASKA; BENZOPYRENE AB In order to determine if exposure to Exxon Valdez oil would adversely affect progeny, reproductively mature Pacific herring were confined in water contaminated with weathered crude oil. Progeny were generally not affected by a 16-d parental exposure to initial aqueous concentrations of less than or equal to 58 mu g/L total polynuclear aromatic hydrocarbons (PAHs), yielding concentrations of up to 9.7 mu g/g in ova. In contrast, previous research indicated that a 16-d direct exposure of herring eggs to similarly weathered oil was detrimental to developing embryos at total initial PAH concentrations of 9 mu g/L. Progeny of exposed fish could have been insulated from toxic effects for two reasons. First, as an apparent result of partitioning and metabolism in parental tissues, lower concentrations and less toxic PAHs were preferentially accumulated by ova (primarily naphthalenes; 84-92%). Second, peak exposure concentrations occurred before cell differentiation. The opposite was true for directly exposed eegs; the more toxic multi-ring PAHs (e.g., phenanthrenes and chrysenes) and alkyl-substituted homologues were accumulated, and internal concentrations increased during cell division, differentiation, and organ development. Thus, Pacific herring embryos are more critically sensitive to oil pollution than are gametes. C1 Natl Ocean & Atmospher Adm, Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr, Auke Bay Lab, Juneau, AK 99801 USA. Occidental Coll, Los Angeles, CA 90041 USA. Calif State Univ Los Angeles, Dept Biol Sci, Chico, CA 91708 USA. RP Carls, MG (reprint author), Natl Ocean & Atmospher Adm, Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr, Auke Bay Lab, 11305 Glacier Highway, Juneau, AK 99801 USA. NR 39 TC 11 Z9 11 U1 2 U2 12 PU SETAC PI PENSACOLA PA 1010 NORTH 12TH AVE, PENSACOLA, FL 32501-3367 USA SN 0730-7268 J9 ENVIRON TOXICOL CHEM JI Environ. Toxicol. Chem. PD JUN PY 2000 VL 19 IS 6 BP 1649 EP 1659 DI 10.1897/1551-5028(2000)019<1649:EOPHTW>2.3.CO;2 PG 11 WC Environmental Sciences; Toxicology SC Environmental Sciences & Ecology; Toxicology GA 318CZ UT WOS:000087267500024 ER PT J AU Stehlik, LL Meise, CJ AF Stehlik, LL Meise, CJ TI Diet of winter flounder in a New Jersey estuary: Ontogenetic change and spatial variation SO ESTUARIES LA English DT Article ID PLAICE PLEURONECTES-PLATESSA; NEW-YORK BIGHT; PSEUDOPLEURONECTES-AMERICANUS; HIPPOGLOSSOIDES-PLATESSOIDES; PASSAMAQUODDY BAY; NEW-BRUNSWICK; DAILY RATION; FOOD; NEWFOUNDLAND; MOVEMENTS AB Juvenile and adult winter flounder, Pseudopleuronectes americanus Walbaum (Pleuronectidae), from the Navesink River and Sandy Hook Bay, New Jersey, U.S., were examined for ontogenetic, seasonal, and spatial variation in dietary content. Fish (n = 1291 non-empty) were placed by cluster analysis of dietary content into three size groups: 15-49, 50-299, and greater than or equal to 300 mm total length. Clear ontogenetic patterns were revealed, in particular the disappearance of calanoid copepods from the diet as fish grew >50 mm and an increase in number of taxa in the diet with growth. Fish in size group 1 fed upon spionid polychaetes, the calanoid copepod Eurytemora affinis, and ampeliscid amphipods. Fish in size group 2 added various species of polychaetes, amphipods, and siphons of the bivalve Mya arenaria to their diets. Size group 2 was present during all months of the survey, but only minor seasonal differences in their diet were apparent. One obvious change was the increase in consumption of the shrimp Crangon septemspinosa in summer and fall. Size group 3 fish, collected mainly in fall, ate large volumes of M. arenaria and glycerid polychaetes. Cluster analysis showed a large-scale spatial pattern in diet among fish of size group 1, related to the presence of E. affinis in winter flounder diets in the river and a marsh cove in the bay. Small-scale spatial differences in diets of fish in size group 2 were possibly related to prey distribution. C1 Natl Marine Fisheries Serv, US Dept Commerce, NOAA,NE Fisheries Sci Ctr, James J Howard Marine Sci Lab, Highlands, NJ 07732 USA. RP Stehlik, LL (reprint author), Natl Marine Fisheries Serv, US Dept Commerce, NOAA,NE Fisheries Sci Ctr, James J Howard Marine Sci Lab, Highlands, NJ 07732 USA. NR 49 TC 45 Z9 48 U1 0 U2 1 PU ESTUARINE RES FEDERATION PI LAWRENCE PA PO BOX 368, LAWRENCE, KS 66044 USA SN 0160-8347 J9 ESTUARIES JI Estuaries PD JUN PY 2000 VL 23 IS 3 BP 381 EP 391 DI 10.2307/1353330 PG 11 WC Environmental Sciences; Marine & Freshwater Biology SC Environmental Sciences & Ecology; Marine & Freshwater Biology GA 333AG UT WOS:000088106100009 ER PT J AU Brodeur, RD Boehlert, GW Casillas, E Eldridge, MB Helle, JH Peterson, WT Heard, WR Lindley, ST Schiewe, MH AF Brodeur, RD Boehlert, GW Casillas, E Eldridge, MB Helle, JH Peterson, WT Heard, WR Lindley, ST Schiewe, MH TI A coordinated research plan for estuarine and ocean research on Pacific salmon SO FISHERIES LA English DT Article ID NORTHERN BRITISH-COLUMBIA; CHINOOK SALMON; CHUM SALMON; ONCORHYNCHUS-TSHAWYTSCHA; SOUTHEASTERN ALASKA; MARINE DISTRIBUTION; JUVENILE SALMONIDS; CLIMATE; OREGON; COAST AB The National Marine Fisheries Service (NMFS) is charged with restoring and protecting anadromous Pacific salmon stocks in all habitats of U.S. waters, including their period of residence in estuarine and oceanic waters. Recent studies have implicated the estuarine and coastal phase of the salmon life cycle as being of equal importance to the freshwater phase in determining production. Evaluation of the freshwater phase of salmon has yielded a better understanding of the factors limiting production in this environment; however, a comparable understanding in the marine environment is lacking. Currently, some marine salmon research is being conducted at various NMFS labs on the West Coast, but there has been little attempt to coordinate activities among the different regions. In response, we propose a comprehensive plan to address ocean and estuarine survival of salmon by identifying research needs and suggesting ways to meet these needs. We recommend that NMFS research focus on (1) distribution and movement patterns of salmon in marine waters, (2) health and condition of hatchery and wild salmon, (3) trophic dynamics of salmon, and (4) large-scale effects of the atmosphere and ocean. C1 NW Fisheries Sci Ctr, Newport, OR 97365 USA. RP Brodeur, RD (reprint author), NW Fisheries Sci Ctr, Newport, OR 97365 USA. EM Rick.Brodeur@noaa.gov RI Lindley, Steven/G-3997-2014 OI Lindley, Steven/0000-0001-9556-0411 NR 78 TC 21 Z9 23 U1 0 U2 3 PU TAYLOR & FRANCIS INC PI PHILADELPHIA PA 530 WALNUT STREET, STE 850, PHILADELPHIA, PA 19106 USA SN 0363-2415 EI 1548-8446 J9 FISHERIES JI Fisheries PD JUN PY 2000 VL 25 IS 6 BP 7 EP 16 DI 10.1577/1548-8446(2000)025<0007:ACRPFE>2.0.CO;2 PG 10 WC Fisheries SC Fisheries GA 325WL UT WOS:000087699400002 ER PT J AU Napp, JM Kendall, AW Schumacher, JD AF Napp, JM Kendall, AW Schumacher, JD TI A synthesis of biological and physical processes affecting the feeding environment of larval walleye pollock (Theragra chalcogramma) in the eastern Bering Sea SO FISHERIES OCEANOGRAPHY LA English DT Article DE Bering Sea; circulation; fisheries oceanography; larval feeding; larval fish survival ID FISHERIES OCEANOGRAPHY; REPRODUCTIVE-BIOLOGY; COPEPOD NAUPLII; SHELIKOF-STRAIT; SPRING BLOOM; SHELF; CIRCULATION; BASIN; ABUNDANCE; DISTRIBUTIONS AB Biological and physical phenomena that affect conditions for larval survival and eventual recruitment differ in the oceanic and shelf regions. In the oceanic region, eddies are a common feature. While their genesis is not well known, eddies have unique biophysical characteristics and occur with such regularity that they likely affect larval survival. High concentrations of larval pollock often are associated with eddies. Some eddies are transported onto the shelf, thereby providing larvae to the Outer Shelf Domain. Advection, rather than local production, dominated the observed springtime increase in chlorophyll (often a correlate of larval food) in the oceanic region. Over two-thirds of the south-eastern shelf, eddies are absent and other phenomena are important. Sea ice is a feature of the shelf region: its interannual variability (time of arrival, persistence, and areal extent) affects developmental rate of larvae, timing of the phytoplankton bloom (and potentially the match/mismatch of larvae and prey), and abundance and distribution of juvenile pollock. In the oceanic region, interannual variation in food for first-feeding pollock larvae is determined by advection; in the shelf region, it is the coupled dynamics of the atmosphere-ice-ocean system. C1 NOAA, Alaska Fisheries Sci Ctr, Seattle, WA 98115 USA. NOAA, Pacific Marine Environm Lab, Seattle, WA 98115 USA. RP Napp, JM (reprint author), NOAA, Alaska Fisheries Sci Ctr, Seattle, WA 98115 USA. EM jeff.napp@noaa.gov NR 80 TC 59 Z9 60 U1 3 U2 16 PU WILEY-BLACKWELL PI HOBOKEN PA 111 RIVER ST, HOBOKEN 07030-5774, NJ USA SN 1054-6006 J9 FISH OCEANOGR JI Fish Oceanogr. PD JUN PY 2000 VL 9 IS 2 BP 147 EP 162 DI 10.1046/j.1365-2419.2000.00129.x PG 16 WC Fisheries; Oceanography SC Fisheries; Oceanography GA 346RT UT WOS:000088885400003 ER PT J AU Walker, RV Myers, KW Davis, ND Aydin, KY Friedland, KD Carlson, HR Boehlert, GW Urawa, S Ueno, Y Anma, G AF Walker, RV Myers, KW Davis, ND Aydin, KY Friedland, KD Carlson, HR Boehlert, GW Urawa, S Ueno, Y Anma, G TI Diurnal variation in thermal environment experienced by salmonids in the North Pacific as indicated by data storage tags SO FISHERIES OCEANOGRAPHY LA English DT Article DE Bering Sea; data storage tags; North Pacific; Pacific salmon; steelhead trout; tagging effects; thermal habitat ID ADULT SOCKEYE SALMON; VERTICAL MOVEMENTS; ONCORHYNCHUS-NERKA; BRITISH-COLUMBIA; ULTRASONIC TELEMETRY; COASTAL WATERS; CHUM SALMON; BEHAVIOR; TSHAWYTSCHA; MIGRATIONS AB Eight temperature-recording data storage tags were recovered from three salmonids in Alaska (pink and coho salmon and steelhead trout) and five chum salmon in Japan after 21-117 days, containing the first long-term records of ambient temperature from Pacific salmonids migrating at sea. Temperature data imply diel patterns of descents to deeper, cooler water and ascents to the surface. Fish were found at higher average temperatures at night, with narrower temperature ranges and fewer descents than during the day. Fish tagged in the Gulf of Alaska were at higher temperatures on average (10-12 degrees C) than chum salmon tagged in the Bering Sea (8-10 degrees C). Chum salmon were also found at a wider range of temperatures (-1-22 degrees C vs 5-15 degrees C). This is probably related both to the different oceanographic regions through which the fish migrated, as well as species differences in thermal range and vertical movements. Proportions of time that individual fish spent at different temperatures seemed to vary among oceanographic regions. Steelhead trout may descend to moderate depths (50 m) and not be limited to the top few metres, as had been believed. Japanese chum salmon may seek deep, cold waters as they encounter warm surface temperatures on their homeward migrations. Temperature data from all fish showed an initial period (4-21 days) of day and night temperatures near those of sea surface temperatures, suggesting a period of recuperation from tagging trauma. A period of tagging recuperation suggests that vertical movement data from short-term ultrasonic telemetry studies may not represent normal behaviour of fish. The considerable diurnal and shorter-term variation in ambient temperatures suggests that offshore ocean distribution may be linked more to prey distribution and foraging than to sea surface temperatures. C1 Univ Washington, Sch Fisheries, Fisheries Res Inst, Seattle, WA 98195 USA. Univ Massachusetts, NOAA, CMER Program, Amherst, MA 01003 USA. Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr, Auke bay Lab, Juneau, AK 99801 USA. Natl Marine Fisheries Serv, SW fisheries Sci Ctr, Pacific Fisheries Environm Lab, Pacific Grove, CA 93950 USA. Fisheries Agcy Japan, Natl Salmon Resources Ctr, Sapporo, Hokkaido 0620922, Japan. Fisheries Agcy Japan, Natl Res Inst Far Seas Fisheries, Shizuoka 4248633, Japan. Hokkaido Univ, Fac Fisheries, Hakodate, Hokkaido 0418611, Japan. RP Walker, RV (reprint author), Univ Washington, Sch Fisheries, Fisheries Res Inst, Box 355020, Seattle, WA 98195 USA. NR 36 TC 57 Z9 61 U1 0 U2 13 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 JUN PY 2000 VL 9 IS 2 BP 171 EP 186 DI 10.1046/j.1365-2419.2000.00131.x PG 16 WC Fisheries; Oceanography SC Fisheries; Oceanography GA 346RT UT WOS:000088885400005 ER PT J AU Verkouteren, JR Leigh, SD AF Verkouteren, JR Leigh, SD TI New low-index liquid refractive index standard: SRM 1922 SO FRESENIUS JOURNAL OF ANALYTICAL CHEMISTRY LA English DT Article ID CRITICAL-ANGLE; REFRACTOMETRY AB A new standard for the calibration of refractometers has been developed. Standard Reference Material (SRM) 1922 is a mineral oil with a refractive index n(D) = 1.46945 at 20 degrees C, which is within the range of the Brix scale (% sucrose). The change in refractive index with temperature (dn/dT) has been characterized for the range 15 degrees C to 35 degrees C to allow for calibrations within that range of temperatures. The refractive indices were measured at 5 wavelengths in the visible spectrum by using the method of minimum deviation with a +/- 2-3 x 10(-5) uncertainty at 20 degrees C. The values of n(D) and dn(D)/dT were determined by fits of a two-term Cauchy function to the values at the measured wavelengths with a +/- 6 x 10(-5) uncertainty in n(D) at 20 degrees C. C1 Natl Inst Stand & Technol, Surface & Microanal Sci Div, Gaithersburg, MD 20899 USA. Natl Inst Stand & Technol, Stat Engn Div, Gaithersburg, MD 20899 USA. RP Verkouteren, JR (reprint author), Natl Inst Stand & Technol, Surface & Microanal Sci Div, Gaithersburg, MD 20899 USA. NR 21 TC 4 Z9 5 U1 0 U2 1 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0937-0633 J9 FRESEN J ANAL CHEM JI Fresenius J. Anal. Chem. PD JUN PY 2000 VL 367 IS 3 BP 226 EP 231 DI 10.1007/s002160000348 PG 6 WC Chemistry, Analytical SC Chemistry GA 329BN UT WOS:000087886400003 PM 11227449 ER PT J AU Bullock, OR AF Bullock, OR TI Current methods and research strategies for modeling atmospheric mercury SO FUEL PROCESSING TECHNOLOGY LA English DT Article; Proceedings Paper CT Conference on Air Quality - Mercury, Trace Elements, and Particulate Matter CY DEC 01-04, 1998 CL MCLEAN, VA SP Univ N Dakota, Energy & Environm Res Ctr, EERC Ctr Air Toxic Metals, US EPA, Natl Ctr Environm Res & Quality Assurance, US DOE, Natl Energy Technol Lab DE atmospheric pathway; mercury; mercury contamination; ecosystems ID TRACE-METALS; AIR; TRANSPORT; CHEMISTRY; EXCHANGE; VAPOR; WATER; DEPOSITION; EMISSIONS; NETWORK AB The atmospheric pathway of the global mercury cycle is known to be the primary source of mercury contamination to most threatened aquatic ecosystems. Current efforts toward numerical modeling of atmospheric mercury are hindered by an incomplete understanding of emissions, atmospheric transformations, and deposition processes. While much effort has been made to quantify the total mass flux of mercury to the atmosphere from various natural and anthropogenic sources, discrimination of the chemical and physical forms of these emissions is just beginning in response to early modeling exercises showing this discrimination to be critical for accurate modeling estimates of the sources responsible for observed mercury deposition. A similar discrimination of ambient concentrations of mercury throughout the atmosphere is needed in order to develop a clear understanding of atmospheric transformation processes, both chemical and physical, which govern the length scale of atmospheric mercury transport and patterns of its deposition in both wet and dry processes. In this paper, current atmospheric mercury modeling techniques and the information obtained from them are described. A strategy for future field research and numerical model development is proposed which is intended to allow a confident identification of the sources of atmospheric mercury responsible for observed contamination of aquatic ecosystems. Published by Elsevier Science B.V. C1 US EPA, Air Resources Lab, Atmospher Sci Modeling Div, NOAA, Res Triangle Pk, NC 27711 USA. RP Bullock, OR (reprint author), US EPA, Air Resources Lab, Atmospher Sci Modeling Div, NOAA, Mail Drop 80, Res Triangle Pk, NC 27711 USA. EM bro@hpcc.epa.gov NR 39 TC 13 Z9 14 U1 1 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0378-3820 J9 FUEL PROCESS TECHNOL JI Fuel Process. Technol. PD JUN PY 2000 VL 65 BP 459 EP 471 DI 10.1016/S0378-3820(99)00110-1 PG 13 WC Chemistry, Applied; Energy & Fuels; Engineering, Chemical SC Chemistry; Energy & Fuels; Engineering GA 326AF UT WOS:000087709000031 ER PT J AU Dickey, JT Swanson, P AF Dickey, JT Swanson, P TI Effects of salmon gonadotropin-releasing hormone on follicle stimulating hormone secretion and subunit gene expression in coho salmon (Oncorhynchus kisutch) SO GENERAL AND COMPARATIVE ENDOCRINOLOGY LA English DT Article DE gonadotropin; fish; gonadotropin-releasing hormone; regulation ID FEMALE RAINBOW-TROUT; MESSENGER-RNA LEVELS; GTH-II-BETA; GOLDFISH PITUITARY-CELLS; BASS MORONE-SAXATILIS; AMINO-ACID-SEQUENCES; ENCODING 2 TYPES; CHICKEN GNRH-II; MOLECULAR-CLONING; CARASSIUS-AURATUS AB Previous work has indicated that, during the process of gametogenesis in salmon, follicle-stimulating hormone (FSH) and luteinizing hormone (LH) are differentially synthesized and released. Although substantial information is available on the regulation of LH in many fish species, relatively little is known about the regulation of FSH biosynthesis and secretion or the regulation of two types of cr subunit in salmon. In this study, the effects of salmon gonadotropin-releasing hormone (sGnRH) on in vitro secretion of FSH, and alpha 1, alpha 2, LH beta, and FSH beta subunit gene expression were investigated in coho salmon (Oncorhynchus kisutch) using primary pituitary cell cultures. To quantify FSH beta, LH beta, alpha 1, and alpha 2 subunit transcript levels, a multiplex RNase protection assay (RPA) was developed. Probes for the beta subunits of coho salmon FSH and LH were available from previous studies. To generate probes for the alpha subunit RPAs, alpha 1 and alpha 2 subunit cDNAs were cloned using reverse transcriptase PCR. Release of FSH and LH into cell culture medium was quantified by radioimmunoassays. The effects of sGnRH on gonadotropin release and gene expression were tested at two points during the spring (April and May) prior to spawning in the autumn; a period when plasma and pituitary FSH levels are increasing and females are in early stages of secondary oocyte growth. In both experiments, sGnRH increased steady-state mRNA levels of FSH beta, alpha 1, and alpha 2, whereas LH beta mRNA levels were not detectable. Secretion of FSH was stimulated by sGnRH in a concentration-dependent manner. Medium LH was not detectable in the first experiment (April) and was measurable only after sGnRH treatment in the second experiment (May). Control levels of medium FSH and transcripts for FSH beta and alpha subunits increased approximately fourfold between April and May, whereas alpha 2 transcript levels remained relatively constant, suggesting that the seasonal increase in FSH release may involve increased production of alpha 1. Therefore, sGnRH has direct stimulatory effects on both secretion of FSH and FSH subunit biosynthesis, most likely due to increased transcription. However, alterations in rates of transcript degradation cannot be ruled out. (C) 2000 Academic Press. C1 NOAA, Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, Seattle, WA 98112 USA. Univ Washington, Sch Fisheries, Seattle, WA 98195 USA. RP Dickey, JT (reprint author), NOAA, Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, 2725 Montalke Blvd E, Seattle, WA 98112 USA. NR 82 TC 59 Z9 59 U1 1 U2 7 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 JUN PY 2000 VL 118 IS 3 BP 436 EP 449 DI 10.1006/gcen.2000.7482 PG 14 WC Endocrinology & Metabolism SC Endocrinology & Metabolism GA 326WP UT WOS:000087760400009 PM 10843795 ER PT J AU Li, XF Clemente-Colon, P Pichel, WG Vachon, PW AF Li, XF Clemente-Colon, P Pichel, WG Vachon, PW TI Atmospheric vortex streets on a RADARSAT SAR image SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID LARGE ISLANDS AB We analyze the sea surface imprint of two atmospheric vortex streets (AVS's) observed on a RADARSAT, a Canadian earth observation satellite, Synthetic Aperture Radar (SAR) image of the Aleutian Islands in the western Gulf of Alaska acquired on May 5, 1999. The RADARSAT SAR instrument is operated in C-band with HH polarization. These AVS's are interpreted as the atmosphere analog of classic Von Karman vortex streets. The SAR image, along with radiosonde data and surface weather charts, reveal that the AVS lengths are 196 km and 111 km for AVS-1 and AVS-2 respectively. There are five and two pairs of Vortices within each AVS. The vortex shedding period is estimated to be between 35 and 48 minutes. The vortex shedding started approximately 4.6 and 2.6 hours prior to the SAR imaging time for AVS-1 and AVS-2, respectively. There are seven and three pairs of vortices within the respective AVS's. The vortex tangential velocity is estimated to be between 1.7 and 2.3 m/s and the energy dissipated during the vortex lifetime is estimated to be between 24.9 and 23.6 J/m(3). C1 NOAA, WWBG, Camp Springs, MD 20746 USA. RP Li, XF (reprint author), NOAA, WWBG, E-RA3,Room 102,5200 Auth Rd, Camp Springs, MD 20746 USA. RI Clemente-Colon, Pablo/F-5581-2010; Pichel, William/F-5619-2010; Li, Xiaofeng/B-6524-2008 OI Pichel, William/0000-0001-6332-0149; Li, Xiaofeng/0000-0001-7038-5119 NR 14 TC 30 Z9 31 U1 1 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUN 1 PY 2000 VL 27 IS 11 BP 1655 EP 1658 DI 10.1029/1999GL011212 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 320GU UT WOS:000087394100023 ER PT J AU Maes, C AF Maes, C TI Salinity variability in the equatorial Pacific Ocean during the 1993-98 period SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID SEA-SURFACE SALINITY; EL-NINO AB The salinity variability during the 1993-98 period in the equatorial Pacific Ocean is estimated by an indirect method based on statistical modes which are fitted to the TAO temperature profiles and the TTP sea level observations. The maximum variability in salinity occurs primarily in the fresh warm pool of the western Pacific. The nature of the variability is consistent with different mechanisms recently proposed. From mid-95 to the end of 1996, positive anomalies of salinity in the upper layers near the eastern edge of the warm pool lead to a negative steric height anomaly which represent up to 30-40% of the thermal counterpart. As a consequence, the heat storage is significantly greater than the one would have inferred from observed sea level fluctuations only. The potential impact of the salinity field during the 1997-98 El Nino event is also discussed. C1 Natl Ocean & Atmospher Adm, Natl Ctr Environm Predict, Washington, DC USA. RP Maes, C (reprint author), MAR, PREVI, SCEM, 42 Ave Coriolis, F-31057 Toulouse, France. RI maes, christophe/L-4049-2015 OI maes, christophe/0000-0001-6532-7141 NR 14 TC 29 Z9 31 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 JUN 1 PY 2000 VL 27 IS 11 BP 1659 EP 1662 DI 10.1029/1999GL011261 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 320GU UT WOS:000087394100024 ER PT J AU Strong, AE Kearns, EJ Gjovig, KK AF Strong, AE Kearns, EJ Gjovig, KK TI Sea surface temperature signals from satellites - An update SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID OCEAN AB Polar satellite-derived observations of sea surface temperatures (SSTs) have been used routinely since 1982 to provide a complete monitoring of our planet, covering all corners of the oceans (unless covered by clouds) twice each day. In 1992, an initial glimpse was published (Strong, 1992) of some tendencies that had been observed during the 1980s. Now that seven additional years of NOAA satellite SST data have become available, the earlier time-series (Strong, 1992) has been up-dated. In this analysis of the global nighttime SSTs, care was taken to avoid the anomalous conditions found during the 1982-83 El Chichon aerosols, 1991-92 Mt. Pinatubo aerosols, and the strong El Nino of 1997-98. Evidence of warming is found to be present throughout much of the Tropics and in the mid-latitude Northern Hemisphere. Estimates from the Southern Hemisphere, while strongly indicative of compensatory cooling in the region, are found to be not as reliable. C1 Natl Environm Satellite Data & Informat Serv, Natl Ocean & Atmospher Adm, Camp Springs, MD 20748 USA. Univ Miami, Rosenstiel Sch Marine & Atmospher Sci, Miami, FL 33149 USA. USN Acad, Dept Oceanog, Annapolis, MD 21402 USA. RP Strong, AE (reprint author), Natl Environm Satellite Data & Informat Serv, Natl Ocean & Atmospher Adm, Camp Springs, MD 20748 USA. RI Strong, Alan/E-7924-2011 NR 14 TC 46 Z9 49 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 JUN 1 PY 2000 VL 27 IS 11 BP 1667 EP 1670 DI 10.1029/1999GL002392 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 320GU UT WOS:000087394100026 ER PT J AU Wilson, RJ Richardson, MI AF Wilson, RJ Richardson, MI TI The Martian atmosphere during the viking mission, I - Infrared measurements of atmospheric temperatures revisited SO ICARUS LA English DT Article DE Mars, atmosphere, climate; atmospheres, dynamics; tides, atmospheric ID GREAT DUST STORMS; GENERAL-CIRCULATION MODEL; MARS ATMOSPHERE; THERMAL TIDES; BOUNDARY-LAYER; ICE CLOUDS; MARINER-9; SURFACE; SPECTROSCOPY; SIMULATION AB The Viking Infrared Thermal Mapper 15-mu m channel brightness temperature observations (IRTM T-15) provide extensive spatial and temporal coverage of martian atmospheric temperatures on diurnal to seasonal time scales. The 15-mu m channel was designed so that these temperatures would be representative of a deep layer of atmosphere centered at 0.5 mb (similar to 25 km), Our re-examination of the IRTM data indicates that the 15-mu m channel was additionally sensitive to surface radiance so that air temperature determinations (nominal T-15) are significantly biased when the thermal contrast between the surface and atmosphere is large. This bias is suggested by the strong correlation between the diurnal variation of tropical T-15 and surface temperatures for non dust-storm conditions. We show that numerical modeling of the thermal tides provides a basis for distinguishing between the surface and atmospheric contributions to IRTM T-15 and thus allows the atmospheric component to be estimated. The resulting bias amounts to a similar to 15-K offset for midday atmospheric temperatures at subsolar latitudes during relatively clear periods and is negligible at night, The proposed temperature correction results in close agreement between the stimulated and observed patterns of diurnal variation for conditions ranging from clear to dusty. A major consequence of this work is the improved definition of the diurnal, latitudinal, and seasonal variation of martian atmosphere temperatures during the Viking mission. An accounting for the surface temperature bias resolves much of the discrepancy between IRTM and corresponding microwave observations, indicating that there is relatively little interannual variability in global temperatures during the aphelion season (L-s similar to 40 degrees-100 degrees), We find further support for this argument in a comparison with T-15 temperatures synthesized from Mariner 9 Infrared Interferometer Spectrometer spectra, The significantly reduced diurnal temperature variations in this season are consistent with the relatively clear atmosphere that is implied by the cooler temperatures. Cooler temperatures and reduced diurnal variation will likely be of significance for the modeling of water ice cloud dynamics in this season. (C) 2000 Academic Press. C1 Geophys Fluid Dynam Lab, Princeton, NJ USA. CALTECH, Div Geol & Planetary Sci, Pasadena, CA 91125 USA. RP Wilson, RJ (reprint author), Geophys Fluid Dynam Lab, Princeton, NJ USA. NR 57 TC 67 Z9 67 U1 1 U2 3 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD JUN PY 2000 VL 145 IS 2 BP 555 EP 579 DI 10.1006/icar.2000.6378 PG 25 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 327KZ UT WOS:000087794200017 ER PT J AU Blaber, SJM Cyrus, DP Albaret, JJ Ching, CV Day, JW Elliott, M Fonseca, MS Hoss, DE Orensanz, J Potter, IC Silvert, W AF Blaber, SJM Cyrus, DP Albaret, JJ Ching, CV Day, JW Elliott, M Fonseca, MS Hoss, DE Orensanz, J Potter, IC Silvert, W TI Effects of fishing on the structure and functioning of estuarine and nearshore ecosystems SO ICES JOURNAL OF MARINE SCIENCE LA English DT Article; Proceedings Paper CT ICES/SCOR Symposium on Ecosystem Effects of Fishing CY MAR 15-19, 1999 CL INST RECH DEV, MONTPELLIER, FRANCE SP ICES, SCOR HO INST RECH DEV DE by-catch; coasts; estuaries; extinctions; fishing; habitats; nurseries; target organisms; trophic effects; water quality ID CATFISH CNIDOGLANIS-MACROCEPHALUS; CALIFORNIA CHANNEL-ISLANDS; ARENICOLA-MARINA; HALIOTIS-CRACHERODII; BENTHIC COMMUNITIES; MANGROVE FORESTS; BLACK ABALONE; CENTRAL CHILE; COSTA-RICA; SEA OTTERS AB Estuaries and associated coastal waters support many essential fisheries, a fact which contributes to their disproportionately high economic value. They are, however, also among the most extensively modified and threatened of aquatic environments. Almost all have been strongly affected by human beings, and fisheries are an integral part of human activities on the coast. We have taken a global perspective in synthesizing the effects of fishing on estuaries and coastal waters. Rather than attempt to cover an regions of the world in detail, we review eight process-orientated categories affected by fishing, with case studies for each of them: target organisms, non-target organisms, nursery functions, trophic effects, habitat change, reduced water quality, human environment, and potential for local extinctions. Fishing in the estuarine and nearshore environment has clear impacts on the structure and functioning of these ecosystems, although other, non-fishing issues also effect these ecosystems. This creates multiple interactions and reinforces the need for an integrated approach to coastal zone management. Nonetheless, some form of fish-based action plan could be created. especially within estuaries, which would provide management objectives for a particular system. (C) 2000 International Council for the Exploration of the Sea. C1 CSIRO, Cleveland, Qld 4163, Australia. Univ Zululand, Dept Zool, Coastal Res Unit Zululand, ZA-3886 KwaDlangezwa, KwaZulu Natal, South Africa. Univ Malaya, Inst Biol Sci, Kuala Lumpur 50603, Malaysia. Louisiana State Univ, Dept Oceanog & Coastal Sci, Baton Rouge, LA 70803 USA. Louisiana State Univ, Coastal Ecol Inst, Baton Rouge, LA 70803 USA. Univ Hull, Inst Estuarine & Coastal Studies, Hull HU6 7RX, N Humberside, England. Natl Ocean Serv, Ctr Coastal Fisheries Habitat Res, Beaufort, NC 28516 USA. Univ Washington, Sch Fisheries, Seattle, WA 98195 USA. Murdoch Univ, Sch Biol Sci, Murdoch, WA 6150, Australia. Bedford Inst Oceanog, Dartmouth, NS B2Y 4A2, Canada. RP Blaber, SJM (reprint author), CSIRO, POB 120, Cleveland, Qld 4163, Australia. RI Chong, Ving Ching/B-4645-2009 NR 117 TC 107 Z9 117 U1 5 U2 40 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 JUN PY 2000 VL 57 IS 3 BP 590 EP 602 DI 10.1006/jmsc.2000.0723 PG 13 WC Fisheries; Marine & Freshwater Biology; Oceanography SC Fisheries; Marine & Freshwater Biology; Oceanography GA 346PL UT WOS:000088880200015 ER PT J AU Livingston, PA Tjelmeland, S AF Livingston, PA Tjelmeland, S TI Fisheries in boreal ecosystems SO ICES JOURNAL OF MARINE SCIENCE LA English DT Article; Proceedings Paper CT ICES/SCOR Symposium on Ecosystem Effects of Fishing CY MAR 15-19, 1999 CL INST RECH DEV, MONTPELLIER, FRANCE SP ICES, SCOR HO INST RECH DEV DE boreal; ecosystem comparison; effects of fishing ID CAPELIN MALLOTUS-VILLOSUS; SOUTHERN LABRADOR; ATLANTIC COD; GADUS-MORHUA; BARENTS SEA; NEWFOUNDLAND; EXPLOITATION; DISTRIBUTIONS; RECRUITMENT; PREDATION AB Northern boreal shelf ecosystems are characterized by relatively few dominant species with strong interactions. The environment is highly dynamic, with strong impacts from oceanographic events that have major influences on fish stocks by altering recruitment, growth, and migration patterns. Excessive catches of one species may lead to the collapse of an important predator or prey in the system and may cause changes in the growth and survival patterns of other species in the food web. Four ecosystems the Barents Sea/Norwegian Sea, the Bering Sea, the Iceland/Jan Mayen area, and the Newfoundland Shelf area - are compared and the impacts of climate and fishing are discussed on the basis of the recent literature. (C) 2000 International Council for the Exploration of the Sea. C1 Alaska Fisheries Sci Ctr, Seattle, WA 98115 USA. Inst Marine Res, N-5024 Bergen, Norway. RP Livingston, PA (reprint author), Alaska Fisheries Sci Ctr, 7600 Sand Point Way NE, Seattle, WA 98115 USA. EM Pat.Livingston@noaa.gov NR 47 TC 20 Z9 21 U1 0 U2 10 PU OXFORD UNIV PRESS PI OXFORD PA GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND SN 1054-3139 J9 ICES J MAR SCI JI ICES J. Mar. Sci. PD JUN PY 2000 VL 57 IS 3 BP 619 EP 627 DI 10.1006/jmsc.2000.0728 PG 9 WC Fisheries; Marine & Freshwater Biology; Oceanography SC Fisheries; Marine & Freshwater Biology; Oceanography GA 346PL UT WOS:000088880200017 ER PT J AU Murawski, SA AF Murawski, SA TI Definitions of overfishing from an ecosystem perspective SO ICES JOURNAL OF MARINE SCIENCE LA English DT Article; Proceedings Paper CT ICES/SCOR Symposium on Ecosystem Effects of Fishing CY MAR 15-19, 1999 CL INST RECH DEV, MONTPELLIER, FRANCE SP ICES, SCOR HO INST RECH DEV DE biodiversity; ecosystem overfishing; fisheries management; habitat effects of fishing; serial depletion; trophic impacts of fishing ID MARINE ECOSYSTEM; FISH STOCKS; FISHERIES; MANAGEMENT; PREDATOR; MODELS; GULF; SIZE AB Ecosystem considerations may be incorporated into fisheries management by modifying existing overfishing paradigms or by developing new approaches to account for ecosystem structure and function in relation to harvesting. Although existing concepts of overfishing have a strong theoretical basis for evaluating policy choices and much practical use, they do not provide direct guidance on issues such as biodiversity, serial depletion, habitat degradation, and changes in the food web caused by fishing. There is, however, little basis for defining optimum fishing by using related metrics such as diversity indices, slopes of size or diversity spectra, or average trophic level of the catch, and these may produce ambiguous results. If ecosystem-based overfishing concepts are to assume a greater rule in management, unambiguous, quantifiable, and predictive measures of ecosystem state and flux must be developed to index: (1) biomass and production by the ecosystem and relationships among its parts, (2) diversity at different levels of organization, (3) patterns of resource variability, and (4) social and economic benefits. Ecosystem considerations do not need to substitute for existing overfishing concepts. Instead, they should be used to evaluate and modify primary management guidance for important fisheries and species. In practice, they emphasize the need to manage fishing capacity, supported by broader use of technical measures such as marine protected areas and gear restrictions. (C) 2000 international Council for the Exploration of the Sea. C1 Natl Marine Fisheries Serv, Woods Hole, MA 02543 USA. RP Murawski, SA (reprint author), Natl Marine Fisheries Serv, Woods Hole, MA 02543 USA. EM Steve.Murawski@noaa.gov NR 51 TC 174 Z9 184 U1 11 U2 90 PU OXFORD UNIV PRESS PI OXFORD PA GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND SN 1054-3139 J9 ICES J MAR SCI JI ICES J. Mar. Sci. PD JUN PY 2000 VL 57 IS 3 BP 649 EP 658 DI 10.1006/jmsc.2000.0738 PG 10 WC Fisheries; Marine & Freshwater Biology; Oceanography SC Fisheries; Marine & Freshwater Biology; Oceanography GA 346PL UT WOS:000088880200020 ER PT J AU Vecchione, M Mickevich, WF Fauchald, K Collette, BB Williams, AB Munroe, TA Young, RE AF Vecchione, M Mickevich, WF Fauchald, K Collette, BB Williams, AB Munroe, TA Young, RE TI Importance of assessing taxonomic adequacy in determining fishing effects on marine biodiversity SO ICES JOURNAL OF MARINE SCIENCE LA English DT Article; Proceedings Paper CT ICES/SCOR Symposium on Ecosystem Effects of Fishing CY MAR 15-19, 1999 CL INST RECH DEV, MONTPELLIER, FRANCE SP ICES, SCOR HO INST RECH DEV DE marine biodiversity; natural resource management; systematics; taxonomy AB Fishing can change the biological diversity of an ecosystem substantially, and determining the effects of fishing on marine biodiversity requires a variety of data, chief among them the proper identification of organisms. Because identification of all organisms in an ecosystem is not currently possible, target taxonomic groups (taxa) must be selected. The current status of taxonomic information varies greatly among taxa and among geographic areas within taxa. Problems include nomenclature, diagnoses, and determination of taxonomic relationships. We provide examples of a variety of these problems. We then propose a series of criteria for evaluating available taxonomic information in determining the potential reliability of species identification, including recency and comprehensiveness of revisionary studies, methods used for systematic and phylogenetic studies, adequacy of documentation, and evidence of peer review. When the goal is to explore biodiversity, these criteria must be used differently from when measuring and monitoring biodiversity. (C) 2000 International Council for the Exploration of the Sea. C1 Natl Museum Nat Hist, Natl Marine Fisheries Serv, Systemat Lab, Washington, DC 20560 USA. Smithsonian Inst, Natl Museum Amer Hist, Dept Invertebrate Zool, Washington, DC 20560 USA. Univ Hawaii Manoa, Dept Oceanog, Honolulu, HI 96822 USA. RP Vecchione, M (reprint author), Natl Museum Nat Hist, Natl Marine Fisheries Serv, Systemat Lab, Washington, DC 20560 USA. NR 12 TC 18 Z9 19 U1 0 U2 5 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 JUN PY 2000 VL 57 IS 3 BP 677 EP 681 DI 10.1006/jmsc.2000.0707 PG 5 WC Fisheries; Marine & Freshwater Biology; Oceanography SC Fisheries; Marine & Freshwater Biology; Oceanography GA 346PL UT WOS:000088880200023 ER PT J AU Hollowed, AB Bax, N Beamish, R Collie, J Fogarty, M Livingston, P Pope, J Rice, JC AF Hollowed, AB Bax, N Beamish, R Collie, J Fogarty, M Livingston, P Pope, J Rice, JC TI Are multispecies models an improvement on single-species models for measuring fishing impacts on marine ecosystems? SO ICES JOURNAL OF MARINE SCIENCE LA English DT Article; Proceedings Paper CT ICES/SCOR Symposium on Ecosystem Effects of Fishing CY MAR 15-19, 1999 CL INST RECH DEV, MONTPELLIER, FRANCE SP ICES, SCOR HO INST RECH DEV DE ecosystem effects of fishing; multispecies models; predation; stock assessment ID FOOD WEBS; POPULATION-DYNAMICS; GEORGES BANK; BALTIC COD; SEA; RECRUITMENT; PREDATION; VARIABILITY; FISHERIES; ABUNDANCE AB We review the application of multispecies models as tools for evaluating impacts of fishing on marine communities. Four types of model are identified: descriptive multispecies, dynamic multispecies, aggregate system, and dynamic system models. The strengths and weaknesses of multispecies models and their ability to evaluate the causal mechanisms underlying shifts in production are examined. This comparison provides a basis for assessing the benefits of each modelling approach as a tool for evaluating impacts of fishing in marine ecosystems. Benefits of multispecies models include: improved estimates of natural mortality and recruitment; better understanding of spawner-recruit relationships and of variability in growth rates; alternative views on biological reference points; and a framework for evaluating ecosystem properties. Populations are regulated by competition (food limitation), predation, and environmental variability. Each factor may influence different life-history stages, locally or regionally. However, most multispecies models address only a subset of these factors. often aggregated over functionally different species or age groups. Models that incorporate the important interactions at specific stages and scales will be necessary if they are to continue to supplement the information provided by single-species models. (C) 2000 International Council for the Exploration of the Sea. C1 Alaska Fisheries Sci Ctr, Seattle, WA 98115 USA. CSIRO, Hobart, Tas 7001, Australia. DFO, Pacific Biol Stn, Nanaimo, BC V6R 5K6, Canada. Univ Rhode Isl, Grad Sch Oceanog, Narragansett, RI 02882 USA. Univ Maryland, Chesapeake Biol Lab, Ctr Environm Sci, Solomons, MD 20688 USA. NRC Europe Ltd, Burgh St Peter NR34 0BT, Norfolk, England. DFO, CSAS, Ottawa, ON K1A 0E6, Canada. RP Hollowed, AB (reprint author), Alaska Fisheries Sci Ctr, 7600 Sand Point Way NE, Seattle, WA 98115 USA. RI Bax, Nicholas/A-2321-2012 OI Bax, Nicholas/0000-0002-9697-4963 NR 85 TC 151 Z9 156 U1 2 U2 28 PU OXFORD UNIV PRESS PI OXFORD PA GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND SN 1054-3139 EI 1095-9289 J9 ICES J MAR SCI JI ICES J. Mar. Sci. PD JUN PY 2000 VL 57 IS 3 BP 707 EP 719 DI 10.1006/jmsc.2000.0734 PG 13 WC Fisheries; Marine & Freshwater Biology; Oceanography SC Fisheries; Marine & Freshwater Biology; Oceanography GA 346PL UT WOS:000088880200027 ER PT J AU Garrison, LP Link, JS AF Garrison, LP Link, JS TI Fishing effects on spatial distribution and trophic guild structure of the fish community in the Georges Bank region SO ICES JOURNAL OF MARINE SCIENCE LA English DT Article; Proceedings Paper CT ICES/SCOR Symposium on Ecosystem Effects of Fishing CY MAR 15-19, 1999 CL INST RECH DEV, MONTPELLIER, FRANCE SP ICES, SCOR HO INST RECH DEV DE dietary overlap; exploitation; Georges Bank; groundfish; spatial distribution AB We examined the changes in the spatial distribution and trophic guild structure of the Georges Bank fish community associated with intense exploitation over the last 30 years. As heavily exploited species declined in abundance, their spatial ranges and degree of overlap with ether species declined. The converse was true for weakly exploited species whose populations have increased. Despite dramatic alterations in species composition, the trophic guild structure was consistent over time. There are five major trophic guilds on Georges Bank across gradients from benthic to pelagic feeders and fish to invertebrate prey. Exploitation has strongly impacted the piscivores in this system and has modified species interactions through alterations in species composition. (C) 2000 International Council for the Exploration of the Sea. C1 Natl Marine Fisheries Serv, NE Fisheries Sci Ctr, Woods Hole, MA 02543 USA. RP Garrison, LP (reprint author), Natl Marine Fisheries Serv, NE Fisheries Sci Ctr, 166 Water St, Woods Hole, MA 02543 USA. NR 11 TC 64 Z9 70 U1 0 U2 14 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 JUN PY 2000 VL 57 IS 3 BP 723 EP 730 DI 10.1006/jmsc.2000.0713 PG 8 WC Fisheries; Marine & Freshwater Biology; Oceanography SC Fisheries; Marine & Freshwater Biology; Oceanography GA 346PL UT WOS:000088880200029 ER PT J AU Little, BE Chu, ST AF Little, BE Chu, ST TI Theory of loss and gain trimming of resonator-type filters SO IEEE PHOTONICS TECHNOLOGY LETTERS LA English DT Article DE microcavity; optical switching; resonators; wavelength filter ID CHANNEL DROPPING FILTERS AB The characteristic response of resonator-type filters is determined by the mutual resonator-to-resonator coupling coefficients, which are not readily trimmed once a device is fabricated. We show that loss and/or gain is a mechanism which can mimic the role of the coupling coefficients, and which can therefore be used Tor post-fabrication tuning or trimming. By using loss-only trimming, the throughput crosstalk performance can be improved by several orders of magnitude while incurring only small signal attenuation. C1 Univ Maryland, Lab Phys Sci, College Pk, MD 20740 USA. MIT, Elect Res Lab, Cambridge, MA 02139 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Little, BE (reprint author), Univ Maryland, Lab Phys Sci, College Pk, MD 20740 USA. RI Chu, Sai /D-3312-2014; OI CHU, Sai Tak /0000-0001-8263-8507 NR 8 TC 8 Z9 8 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 1041-1135 J9 IEEE PHOTONIC TECH L JI IEEE Photonics Technol. Lett. PD JUN PY 2000 VL 12 IS 6 BP 636 EP 638 DI 10.1109/68.849068 PG 3 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA 334VW UT WOS:000088207200016 ER PT J AU Baker-Jarvis, J AF Baker-Jarvis, J TI A generalized dielectric polarization evolution equation SO IEEE TRANSACTIONS ON DIELECTRICS AND ELECTRICAL INSULATION LA English DT Article ID PROBABILISTIC MECHANISM HIDDEN; UNIVERSAL POWER LAW; SUPERPOSITION PRINCIPLE; RELAXATION EQUATION; MODEL; CONDUCTIVITY; DISPERSION; BEHAVIOR; POLYMERS; SYSTEMS AB In this paper a non-equilibrium statistical-mechanical theory of dielectric relaxation is developed. This approach differs from previous work in that a generalized nonlocal evolution equation for the polarization is constructed. General equations of motion are presented for the polarization, internal energy, and entropy which include effects of memory. These equations can be expressed in terms of reduced-correlation functions, and are valid for non-equilibrium and arbitrary field strengths. Expressions for an effective local field also are developed. The Fourier transform of the evolution equation yields a general compact expression for the Fourier transform of the memory function and a specific form for the susceptibility. The kernel, Fourier transform of the memory function are developed, and relaxation-time functions for special cases. In the limit of a single relaxation time, a Debye response is obtained. In the subsequent special cases exponential and Gaussian forms for the memory functions are assumed. The final special case relates a power-law circuit transfer function to the theory of Dissado and Hill. In this case the memory kernel and relaxation times are derived from the Dissado-Hill response function. C1 Natl Inst Stand & Technol, Boulder, CO USA. RP Baker-Jarvis, J (reprint author), Natl Inst Stand & Technol, Boulder, CO USA. NR 53 TC 7 Z9 7 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 1070-9878 J9 IEEE T DIELECT EL IN JI IEEE Trns. Dielectr. Electr. Insul. PD JUN PY 2000 VL 7 IS 3 BP 374 EP 386 DI 10.1109/94.848919 PG 13 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA 329UQ UT WOS:000087927200011 ER PT J AU Vogel, EM Suehle, JS Edelstein, MD Wang, B Chen, Y Bernstein, JB AF Vogel, EM Suehle, JS Edelstein, MD Wang, B Chen, Y Bernstein, JB TI Reliability of ultrathin silicon dioxide under combined substrate hot-electron and constant voltage tunneling stress SO IEEE TRANSACTIONS ON ELECTRON DEVICES LA English DT Article DE MOS; oxide; reliability; tunnel ID DEPENDENT DIELECTRIC-BREAKDOWN; INDUCED LEAKAGE CURRENTS; DEFECT GENERATION; IMPACT IONIZATION; OXIDE BREAKDOWN; DYNAMIC-STRESS; FILMS; INJECTION; DEGRADATION; MODEL AB An experimental investigation of breakdown and defect generation under combined substrate hot-electron and tunneling electrical stress of silicon oxide ranging in thickness from 2.0 nm to 3.5 nm is reported. Using independent control of the gate current for a given substrate and gate bias, the time-to-breakdown of ultrathin silicon dioxide under substrate hot-electron stress is observed to be inversely proportional to the gate current density, The thickness dependence (2.0 nm to 3.5 nm) of substrate hot-electron reliability is reported and shown to be similar to constant voltage tunneling stress. The build-up of defects measured using stress-induced-leakage-current and charge-pumping for both tunneling and substrate hot-electron stress is reported. Based on these and previous results, a model is proposed to explain the time-to-breakdown behavior of ultrathin oxide under simultaneous tunneling and substrate hot-electron stress. The results and model provide a coherent understanding for describing the reliability of ultrathin SiO2 under combined substrate hot-electron injection and constant voltage tunneling stress. C1 NIST, Div Semicond Elect, Gaithersburg, MD 20899 USA. Univ Maryland, Reliabil Engn Program, Dept Mat & Nucl Engn, College Pk, MD 20742 USA. RP Vogel, EM (reprint author), NIST, Div Semicond Elect, Gaithersburg, MD 20899 USA. RI Vogel, Eric/A-7731-2008 OI Vogel, Eric/0000-0002-6110-1361 NR 42 TC 32 Z9 32 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 0018-9383 J9 IEEE T ELECTRON DEV JI IEEE Trans. Electron Devices PD JUN PY 2000 VL 47 IS 6 BP 1183 EP 1191 DI 10.1109/16.842960 PG 9 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA 318PB UT WOS:000087291900008 ER PT J AU Lee, KB Schneeman, RD AF Lee, KB Schneeman, RD TI Distributed measurement and control based on the IEEE 1451 Smart Transducer Interface standards SO IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT LA English DT Article DE control network; distributed measurement and control; field network; IEEE 1451; industrial automation; interface; plug and play; sensor; sensor network; smart transducer; TEDS AB This paper details a framework developed at the National Institute of Standards and Technology (NIST) that highlights the standardization efforts going on within the various levels of an Internet-based distributed measurement and control (DMC) system. The framework highlights state-of-the-art hardware and software techniques used at NIST to design, implement, and deploy next-generation Internet-based DMC applications and systems. The framework targets three important areas of standardization including transducer interfaces, open network communication, and distributed application development. An implementation of a DMC application on the Internet based on the NIST framework Is also described. The paper concludes with a brief introduction to other research activities at NIST culminating from this core Internet-based DMC research. C1 Natl Inst Stand & Technol, Sensor Integrat Grp, Gaithersburg, MD 20899 USA. RP Lee, KB (reprint author), Natl Inst Stand & Technol, Sensor Integrat Grp, Gaithersburg, MD 20899 USA. NR 10 TC 54 Z9 57 U1 1 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 JUN PY 2000 VL 49 IS 3 BP 621 EP 627 DI 10.1109/19.850405 PG 7 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA 334FA UT WOS:000088174800028 ER PT J AU Long, GG Levine, LE Thomson, R AF Long, GG Levine, LE Thomson, R TI In-situ observation of small-angle X-ray scattering by dislocations SO JOURNAL OF APPLIED CRYSTALLOGRAPHY LA English DT Article; Proceedings Paper CT XIth International Conference on Small-Angle Scattering CY MAY 17-20, 1999 CL BROOKHAVEN NATL LAB, LONG ISL CITY, NEW YORK SP NatDOE, Off Basic Energy Sci, Int Union Crystallog, Intense Pulsed Neutron Sourch, Neutron Scattering Soc Amer, Stanford Synchrotron Radiat Lab, Oak Ridge Natl Lab, Synchrotron Radiat Res Ctr, Exxon Res & Engn Co, Natl Ctr Neutron Res, USAF Res Lab, Dow Chem Co, Photon Factory, Cornell High energy Synchrotron Source, DSM Res, Brookhaven Sci Associates, BNL Biol Dept, BNL Phys Dept HO BROOKHAVEN NATL LAB ID TRANSMISSION ELECTRON-MICROSCOPY; RESOLUTION AB Ultra-small-angle X-ray scattering by dislocations in single-crystal aluminum has been observed in situ as a function of plastic deformation. The scattering is strongly dependent upon sample orientation, with single dislocations, dislocation dipoles, and the dislocation distribution within walls each exhibiting distinct scattering profiles. Among the microstructural features that have been observed are: the correlations between the ordered fraction of dislocations, the presence of dislocation dipoles, the increasing dislocation content with increasing strain, and the decreasing width of the interface between dislocation walls and the surrounding nearly-dislocation-free material with increasing deformation. C1 Natl Inst Stand & Technol, Mat Sci & Engn Lab, Gaithersburg, MD 20899 USA. RP Long, GG (reprint author), Natl Inst Stand & Technol, Mat Sci & Engn Lab, Gaithersburg, MD 20899 USA. NR 13 TC 8 Z9 8 U1 0 U2 0 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0021-8898 J9 J APPL CRYSTALLOGR JI J. Appl. Crystallogr. PD JUN 1 PY 2000 VL 33 IS 1 BP 456 EP 460 DI 10.1107/S0021889899016258 PN 3 PG 5 WC Chemistry, Multidisciplinary; Crystallography SC Chemistry; Crystallography GA 317VX UT WOS:000087248600010 ER PT J AU Schaefer, DW Rieker, T Agamalian, M Lin, JS Fischer, D Sukumaran, S Chen, CY Beaucage, G Herd, C Ivie, J AF Schaefer, DW Rieker, T Agamalian, M Lin, JS Fischer, D Sukumaran, S Chen, CY Beaucage, G Herd, C Ivie, J TI Multilevel structure of reinforcing silica and carbon SO JOURNAL OF APPLIED CRYSTALLOGRAPHY LA English DT Article; Proceedings Paper CT XIth International Conference on Small-Angle Scattering CY MAY 17-20, 1999 CL BROOKHAVEN NATL LAB, LONG ISL CITY, NEW YORK SP NatDOE, Off Basic Energy Sci, Int Union Crystallog, Intense Pulsed Neutron Sourch, Neutron Scattering Soc Amer, Stanford Synchrotron Radiat Lab, Oak Ridge Natl Lab, Synchrotron Radiat Res Ctr, Exxon Res & Engn Co, Natl Ctr Neutron Res, USAF Res Lab, Dow Chem Co, Photon Factory, Cornell High energy Synchrotron Source, DSM Res, Brookhaven Sci Associates, BNL Biol Dept, BNL Phys Dept HO BROOKHAVEN NATL LAB ID SMALL-ANGLE SCATTERING; POWER-LAW APPROACH; X-RAY-SCATTERING; COMBUSTION AEROSOLS; AEROGELS AB Using small-angle x-ray (SAXS), neutron (SANS), x-ray diffraction and light scattering, we study the structure of colloidal silica and carbon on length scales from 4 Angstrom < q(-1) < 10(7) Angstrom where q is the magnitude of the scattering vector. These materials consist of primary particles of the order of 100 Angstrom, aggregated into micron-sized aggregates that in turn are agglomerated into 100 mu agglomerates. The diffraction data show that the primary particles in precipitated silica are composed of highly defective amorphous silica with little intermediate-range order (order on the scale of several bond distances). On the next level of morphology, primary particles arise by a complex nucleation process in which primordial nuclei briefly aggregate into rough particles that subsequently smooth out to become the seeds for the primaries. The primaries aggregate to strongly bonded clusters by a complex process involving kinetic growth, mechanical disintegration and restructuring. Finally, the small-angle scattering (SAS) data lead us to postulate that the aggregates cluster into porous, rough-surfaced, non-mass-fractal agglomerates that can be broken down to the more strongly bonded aggregates by application of shear. We find similar structure in pelletized carbon blacks. In this case we show a linear scaling relation between the primary and aggregate sizes. We attribute the scaling to mechanical processing that deforms the fractal aggregates down to the maximum size able to withstand the compaction stress. Finally, we rationalize the observed structure based on empirical optimization by filler suppliers and some recent theoretical ideas due to Witten, Rubenstein and Colby. C1 Univ Cincinnati, Cincinnati, OH 45221 USA. Univ New Mexico, Albuquerque, NM 87131 USA. Oak Ridge Natl Lab, Div Solid State, Oak Ridge, TN 37831 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Columbian Chem Co, Marietta, GA 30062 USA. RP Schaefer, DW (reprint author), Univ Cincinnati, Cincinnati, OH 45221 USA. RI USAXS, APS/D-4198-2013; OI Agamalian, Michael/0000-0002-9112-2534 NR 18 TC 60 Z9 61 U1 0 U2 18 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0021-8898 J9 J APPL CRYSTALLOGR JI J. Appl. Crystallogr. PD JUN 1 PY 2000 VL 33 IS 1 BP 587 EP 591 DI 10.1107/S0021889800001199 PN 3 PG 5 WC Chemistry, Multidisciplinary; Crystallography SC Chemistry; Crystallography GA 317VX UT WOS:000087248600041 ER PT J AU Kline, S AF Kline, S TI Structural evolution during micelle polymerization SO JOURNAL OF APPLIED CRYSTALLOGRAPHY LA English DT Article; Proceedings Paper CT XIth International Conference on Small-Angle Scattering CY MAY 17-20, 1999 CL BROOKHAVEN NATL LAB, LONG ISL CITY, NEW YORK SP NatDOE, Off Basic Energy Sci, Int Union Crystallog, Intense Pulsed Neutron Sourch, Neutron Scattering Soc Amer, Stanford Synchrotron Radiat Lab, Oak Ridge Natl Lab, Synchrotron Radiat Res Ctr, Exxon Res & Engn Co, Natl Ctr Neutron Res, USAF Res Lab, Dow Chem Co, Photon Factory, Cornell High energy Synchrotron Source, DSM Res, Brookhaven Sci Associates, BNL Biol Dept, BNL Phys Dept HO BROOKHAVEN NATL LAB ID POLYELECTROLYTE-SURFACTANT COMPLEXES; ANGLE NEUTRON-SCATTERING; TRANSITION; MONOMERS AB The evolution of microstructure during the free-radical polymerization of the surfactant cetyltrimethylammonium 4-vinylbenzoate has been measured using small-angle neutron scattering. The polymerization of the micelles was performed online, collecting SANS data continuously during the polymerization. Unlike microemulsion polymerizations, this micellar polymerization is seen to proceed through a highly turbid phase with local, short-range order at a length scale of approximately 50 Angstrom. A simple structural model has been proposed to quantify the structural changes during the course of the reaction. The ordered structure is postulated to be an ordered bundle of cylindrical micelles, which subsequently breaks up into the final equilibrium structure of discrete, polymerized cylinders. C1 NIST, Ctr Neutron Res, Gaithersburg, MD 20899 USA. RP Kline, S (reprint author), NIST, Ctr Neutron Res, 100 Bur Dr,Stop 8562, Gaithersburg, MD 20899 USA. NR 18 TC 30 Z9 31 U1 0 U2 3 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0021-8898 J9 J APPL CRYSTALLOGR JI J. Appl. Crystallogr. PD JUN 1 PY 2000 VL 33 IS 1 BP 618 EP 622 DI 10.1107/S0021889899012753 PN 3 PG 5 WC Chemistry, Multidisciplinary; Crystallography SC Chemistry; Crystallography GA 317VX UT WOS:000087248600048 ER PT J AU Barnes, JD Kolb, R Barnes, K Nakatani, AI Hammouda, B AF Barnes, JD Kolb, R Barnes, K Nakatani, AI Hammouda, B TI Microstructure analysis using temperature-induced contrast variation in small-angle scattering SO JOURNAL OF APPLIED CRYSTALLOGRAPHY LA English DT Article; Proceedings Paper CT XIth International Conference on Small-Angle Scattering CY MAY 17-20, 1999 CL BROOKHAVEN NATL LAB, LONG ISL CITY, NEW YORK SP NatDOE, Off Basic Energy Sci, Int Union Crystallog, Intense Pulsed Neutron Sourch, Neutron Scattering Soc Amer, Stanford Synchrotron Radiat Lab, Oak Ridge Natl Lab, Synchrotron Radiat Res Ctr, Exxon Res & Engn Co, Natl Ctr Neutron Res, USAF Res Lab, Dow Chem Co, Photon Factory, Cornell High energy Synchrotron Source, DSM Res, Brookhaven Sci Associates, BNL Biol Dept, BNL Phys Dept HO BROOKHAVEN NATL LAB ID SYNDIOTACTIC POLYSTYRENE AB We propose to introduce Temperature-Induced Contrast Variation (TICV) as a technique for improving the specificity of microstructure analyses obtained using small-angle scattering methods. TICV exploits the fact that, at temperatures well removed from melting or annealing regimes, the scattering contrast in many multicomponent systems exhibits a significant temperature dependence while the form factors for the scattering processes change only slightly. Difference scattering patterns formed by subtracting the pattern measured at a suitable reference temperature from the pattern obtained at another temperature emphasize those components of the microstructure that vary most strongly with temperature over the chosen range. This can facilitate an effective separation of the observed scattering patterns into separate components for differing scattering mechanisms. Examples of distinct scattering mechanisms commonly found in polymers include liquidlike scattering from amorphous components, contributions from the intramolecular amorphous halo, Guinier scattering from inclusions, and the scattering from ordered stacks of crystalline lamellae. The experimental data presented here provide qualitative demonstrations of general features of the method. Further work is needed to obtain improved descriptors to characterize microstructure in these systems. C1 NIST, Polymer Characterizat Grp, Gaithersburg, MD 20899 USA. Exxon Res & Engn Co, Annandale, NJ 08801 USA. NIST, Ctr Neutron Res, Gaithersburg, MD 20899 USA. RP Barnes, JD (reprint author), NIST, Polymer Characterizat Grp, Gaithersburg, MD 20899 USA. NR 13 TC 4 Z9 4 U1 0 U2 3 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0021-8898 J9 J APPL CRYSTALLOGR JI J. Appl. Crystallogr. PD JUN 1 PY 2000 VL 33 IS 1 BP 758 EP 762 DI 10.1107/S0021889800099830 PN 3 PG 5 WC Chemistry, Multidisciplinary; Crystallography SC Chemistry; Crystallography GA 317VX UT WOS:000087248600080 ER PT J AU Gentile, TR Jones, GL Thompson, AK Barker, J Glinka, CJ Hammouda, B Lynn, JW AF Gentile, TR Jones, GL Thompson, AK Barker, J Glinka, CJ Hammouda, B Lynn, JW TI SANS polarization analysis with nuclear-spin-polarized He-3 SO JOURNAL OF APPLIED CRYSTALLOGRAPHY LA English DT Article; Proceedings Paper CT XIth International Conference on Small-Angle Scattering CY MAY 17-20, 1999 CL BROOKHAVEN NATL LAB, LONG ISL CITY, NEW YORK SP NatDOE, Off Basic Energy Sci, Int Union Crystallog, Intense Pulsed Neutron Sourch, Neutron Scattering Soc Amer, Stanford Synchrotron Radiat Lab, Oak Ridge Natl Lab, Synchrotron Radiat Res Ctr, Exxon Res & Engn Co, Natl Ctr Neutron Res, USAF Res Lab, Dow Chem Co, Photon Factory, Cornell High energy Synchrotron Source, DSM Res, Brookhaven Sci Associates, BNL Biol Dept, BNL Phys Dept HO BROOKHAVEN NATL LAB ID SCATTERING AB A neutron spin filter based on transmission through nuclear-spin-polarized He-3 gas has been applied to polarization analysis of small angle neutron scattering (SANS). Such spin filters, which are based on the large spin dependence of the absorption of neutrons by He-3, make SANS polarization analysis possible because of their large angular acceptance. In the present experiment, a He-3-based analyzer was employed to separate nuclear scattering into its coherent and spin-incoherent components. Polarized He-3 analyzers were prepared by two different optical pumping methods and installed on the NG3 SANS instrument at the NIST Center for Neutron Research (NCNR). Measurements were taken on cellophane tape and silica gel, for which the scattering is almost completely incoherent and coherent, respectively, and on a combined sample. For the combined sample, separation of the coherent part from the incoherent part was successfully demonstrated using polarization analysis. C1 NIST, Gaithersburg, MD 20899 USA. RP Gentile, TR (reprint author), NIST, Stop 8461, Gaithersburg, MD 20899 USA. NR 11 TC 36 Z9 36 U1 0 U2 0 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0021-8898 J9 J APPL CRYSTALLOGR JI J. Appl. Crystallogr. PD JUN 1 PY 2000 VL 33 IS 1 BP 771 EP 774 DI 10.1107/S0021889800099817 PN 3 PG 4 WC Chemistry, Multidisciplinary; Crystallography SC Chemistry; Crystallography GA 317VX UT WOS:000087248600083 ER PT J AU Choi, SM Barker, JG Glinka, CJ Cheng, YT Gammel, PL AF Choi, SM Barker, JG Glinka, CJ Cheng, YT Gammel, PL TI Focusing cold neutrons with multiple biconcave lenses for small-angle neutron scattering SO JOURNAL OF APPLIED CRYSTALLOGRAPHY LA English DT Article; Proceedings Paper CT XIth International Conference on Small-Angle Scattering CY MAY 17-20, 1999 CL BROOKHAVEN NATL LAB, LONG ISL CITY, NEW YORK SP NatDOE, Off Basic Energy Sci, Int Union Crystallog, Intense Pulsed Neutron Sourch, Neutron Scattering Soc Amer, Stanford Synchrotron Radiat Lab, Oak Ridge Natl Lab, Synchrotron Radiat Res Ctr, Exxon Res & Engn Co, Natl Ctr Neutron Res, USAF Res Lab, Dow Chem Co, Photon Factory, Cornell High energy Synchrotron Source, DSM Res, Brookhaven Sci Associates, BNL Biol Dept, BNL Phys Dept HO BROOKHAVEN NATL LAB AB The focusing of a cold neutron beam by multiple biconcave lenses has recently been proposed as a practical means of extending the lower limit of Q in conventional, long flight-path small-angle neutron scattering (SANS) instruments. To test the feasibility of this approach, we have carried out extensive measurements on one of the 30 m SANS instruments at NIST of the focusing characteristics of a set of 28 biconcave MgF2 lenses. The focused beam profile has been measured over several orders of magnitude using high resolution neutron auto-radiography. The focusing lens configuration outperforms the pinhole collimation at Q(min) lower than 0.004 Angstrom(-1). At Q(min) = 0.001 Angstrom(-1), the intensity gain of the lens configuration over the pinhole collimation is greater than one order of magnitude. C1 Natl Inst Stand & Technol, Ctr Neutron Res, Gaithersburg, MD 20899 USA. Univ Maryland, Dept Mat & Nucl Engn, College Pk, MD 20742 USA. NeuTek, Darnestown, MD 20878 USA. Lucent Technol, Bell Labs, Murray Hill, NJ 07974 USA. RP Choi, SM (reprint author), Natl Inst Stand & Technol, Ctr Neutron Res, Gaithersburg, MD 20899 USA. NR 9 TC 106 Z9 107 U1 0 U2 8 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0021-8898 J9 J APPL CRYSTALLOGR JI J. Appl. Crystallogr. PD JUN 1 PY 2000 VL 33 IS 1 BP 793 EP 796 DI 10.1107/S0021889800099799 PN 3 PG 4 WC Chemistry, Multidisciplinary; Crystallography SC Chemistry; Crystallography GA 317VX UT WOS:000087248600089 ER PT J AU Reinking, RF Snider, JB Coen, JL AF Reinking, RF Snider, JB Coen, JL TI Influences of storm-embedded orographic gravity waves on cloud liquid water and precipitation SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID WINTER STORM; RADAR; EVOLUTION; ARIZONA; TERRAIN AB This study illustrates opportunities for much improved orographic quantitative precipitation forecasting, determination of orographic cloud seedability, and flash flood prediction through state-of-the-art remote sensing and numerical modeling of gravity wave clouds. Wintertime field observations with multiple remote sensors, corroborated in this and related papers with a mesoscale-cloud scale numerical simulation, confirm that storm-embedded gravity waves can have a strong and persistent influence on orographic cloud liquid water (CLW) and precipitation. Where parallel mountain ridges dominate the landscape, an upwind ridge can force the wave action, and a downwind ridge can receive the precipitation; The 1995 Arizona Program was conducted in such terrain. In the scenario examined, traveling waves cyclically caused prefrontal cross-barrier winds that produced gravity waves. Significant cloud bands associated with the waves carried substantial moisture to the area. With the passage and waning of the cloud bands, vapor influxes (precipitable water P-w) cycled through large changes in magnitude, and prefrontal peaks in P-w. coincided with the gravity waves in a succession of episodes during a five-day period. Thus, the cyclic trend in P-w and the magnitudes of peak P-w were simple indicators of wave cloud development. The first two cycles, with minor peak P-w, were precursors. Significant wave clouds first appeared during the second episode. During the final two episodes with large vapor influxes, very deep, precipitating wave clouds were coupled with underlying clouds formed in how up the mountain slopes to create the prefrontal storms. Rain fell on an existing snowpack on the main recipient ridge and, in the end, produced rapid runoff and flash flooding. The gravity waves persistently condensed CLW that averaged 0.5 mm and reached 1.0 mm in the first of the main storm episodes, and averaged 1.0 mm and reached 2.0 mm and more in the second (column-integrated values). These values equaled or exceeded the larger of those represented in liquid water climate datasets for orographic cloud systems in other locations in the West, where only the upslope and not the wave component had been examined. The effect of shifts between cross-barrier and barrier-parallel flows was reflected in abrupt buildups and declines in wave CLW but the gravity wave clouds persisted for a total of 22 h during the two storm periods. In the wave updrafts, the condensation rate regularly exceeded the consumption rate by ice, even though ice was usually present. Conversion to ice consumed and precipitated wave CLW. Pulses of available P-w and wave CLW on a 2- to 4-h timescale, cyclically followed by partial glaciation, produced the precipitation from the wave clouds. Their seeder effect on the upslope feeder clouds was to enhance the total precipitation from the coupled system. Estimates of the liquid water fluxes in comparison with the precipitation rates suggest precipitation efficiencies in the 11%-33% range from the seeder-feeder couplets. The periods of gravity wave forcing contributed some 80% or more of the total precipitation, and trailing fronts produced the remainder. Several factors derived from the observed availability of CLW determine the potential for precipitation enhancement by seeding wave clouds; these are enumerated. Given demands for improved water supply, the challenge often presented in mountain watersheds of separating seeding opportunities from potential flash hood situations is examined. The results here show that storms that could threaten flash floods can be readily identified by continuous monitoring with polarization radar and in real-time simulations as those with the altitude of the melting level above the elevation of the highest terrain with existing snowpack. In the sense that orographically generated gravity waves will significantly influence cloud water and precipitation, geographic transferability of the results is indicated by the existence of wave-generating and precipitation-generating parallel ridges in many places throughout the world. The quantitative effects will, of course, depend on particulars of the locale such as nature of the prevalent forcing, available moisture, and physical stature of the ridges. C1 NOAA, OAR, ETL, Boulder, CO 80303 USA. Univ Colorado, CIRES, Boulder, CO 80309 USA. Natl Ctr Atmospher Res, MMM Div, Boulder, CO 80307 USA. RP Reinking, RF (reprint author), NOAA, OAR, ETL, R-E-ET6,325 Broadway, Boulder, CO 80303 USA. NR 29 TC 30 Z9 30 U1 1 U2 4 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 JUN PY 2000 VL 39 IS 6 BP 733 EP 759 DI 10.1175/1520-0450(2000)039<0733:IOSEOG>2.0.CO;2 PG 27 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 324YT UT WOS:000087650100001 ER PT J AU Cifelli, R Williams, CR Rajopadhyaya, DK Avery, SK Gage, KS May, PT AF Cifelli, R Williams, CR Rajopadhyaya, DK Avery, SK Gage, KS May, PT TI Drop-size distribution characteristics in tropical mesoscale convective systems SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID WIND PROFILER; VERTICAL VELOCITY; RAINDROP SPECTRA; RADAR; RAINFALL; PRECIPITATION; RETRIEVAL; CLOUDS; UHF; REFLECTIVITY AB Drop-size distribution characteristics were retrieved in eight tropical mesoscale convective systems (MCS) using a dual-frequency (UHF and VHF) wind profiler technique. The MCSs occurred near Darwin, Australia, during the 1993/94 wet season and were representative of the monsoon (oceanic) regime. The retrieved drop-size parameters were compared with corresponding rain gauge and disdrometer data, and it was found that there was good agreement between the measurements, lending credence to the profiler retrievals of drop-size distribution parameters. The profiler data for each MCS were partitioned into a three-tier classification scheme (i.e., convective, mixed convective-stratiform, and stratiform) based on a modified version of Williams et al. to isolate the salient microphysical characteristics in different precipitation types. The resulting analysis allowed for an examination of the drop-size distribution parameters in each category for a height range of about 2.1 km in each MCS. In general, the distributions of all of the retrieved parameters showed the most variability in convection and the least in stratiform, with the mixed convective-stratiform category usually displaying intermediate characteristics. Although there was significant overlap in the range of many of the parameter distributions, the mean profiles were distinct. In the stratiform region, there was minimal vertical structure for all of the drop-size distribution parameters. This result suggests an equilibrium between depletion (e.g., evaporation) and growth (e.g., coalescence) over the height range examined. In contrast, the convective parameter distributions showed a more complicated structure, probably as a consequence of the complex microphysical processes occurring in the convective precipitation category. Reflectivity-rainfall (Z-R) relations of the form Z = AR(B) were developed for each precipitation category as a function of height using linear regressions to the profiler retrievals of R and Z in log space. Similar to findings from previous studies, the rainfall decreased for a given reflectivity as the precipitation type changed from convective to stratiform. This result primarily was due to the fact that the coefficient A in the best-fit stratiform ZR was approximately a factor of 2 greater than the convective A at all heights. The coefficient A generally increased downward with height in each category; the exponent B showed a small decrease (stratiform), almost no change (convective), or a slight increase (mixed convective-stratiform). Consequently, the amount by which convective rain rate exceeded stratiform (for a given reflectivity) varied significantly as a function of height, ranging from about 15% to over 80%. C1 Univ Maryland Baltimore Cty, Joint Ctr Earth Syst Technol, Baltimore, MD 21228 USA. Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. NOAA, Aeron Lab, Boulder, CO 80303 USA. Bur Res Meteorol Ctr, Melbourne, Vic, Australia. RP Cifelli, R (reprint author), Colorado State Univ, Dept Atmospher Sci, Ft Collins, CO 80523 USA. RI Williams, Christopher/A-2723-2015 OI Williams, Christopher/0000-0001-9394-8850 NR 50 TC 51 Z9 55 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 JUN PY 2000 VL 39 IS 6 BP 760 EP 777 DI 10.1175/1520-0450(2000)039<0760:DSDCIT>2.0.CO;2 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 324YT UT WOS:000087650100002 ER PT J AU Basara, JB Crawford, TM AF Basara, JB Crawford, TM TI Improved installation procedures for deep-layer soil moisture measurements SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article ID SENSOR AB The Oklahoma Mesonet, an automated network of 115 meteorological observing stations, includes soil moisture monitoring devices at 60 locations. The Campbell Scientific model 229-L matric potential (water potential) sensor was chosen for operational use based on its capability to perform as a fully automated soil water measuring device. Extensive laboratory calibrations were performed on each sensor to ensure the quality of the matric potential measurements. Examination of the data from the Norman site during July 1997 revealed significant inconsistencies between near-surface (5 and 25 cm) measurements of soil moisture and deep-layer (60 and 75 cm) measurements of soil moisture. In particular, a heavy precipitation event was followed by only a small increase in near-surface soil water potential values, while a much larger increase occurred in the deep-layer values. It is theorized that an installation flaw is the cause for these inconsistencies. A solution is proposed in the hope that future efforts to measure soil moisture will not be hindered by similar problems. C1 Univ Oklahoma, Oklahoma Climatol Survey, Norman, OK 73019 USA. Univ Oklahoma, Cooperat Inst Mesoscale Meteorol Studies, Natl Severe Storms Lab, Norman, OK 73019 USA. RP Basara, JB (reprint author), Univ Oklahoma, Oklahoma Climatol Survey, 100 E Boyd St,Suite 1210, Norman, OK 73019 USA. RI Basara, Jeffrey/A-4907-2008 OI Basara, Jeffrey/0000-0002-2096-6844 NR 14 TC 37 Z9 37 U1 1 U2 3 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0739-0572 J9 J ATMOS OCEAN TECH JI J. Atmos. Ocean. Technol. PD JUN PY 2000 VL 17 IS 6 BP 879 EP 884 DI 10.1175/1520-0426(2000)017<0879:IIPFDL>2.0.CO;2 PG 6 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA 326XR UT WOS:000087763000011 ER PT J AU Steffens, KL Crosley, DR AF Steffens, KL Crosley, DR TI Vibrational energy transfer in OH A(2)Sigma(+) between 195 and 295 K SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID TRANSITION-PROBABILITIES; A2-SIGMA+ OH; TEMPERATURES; RADICALS; A(2)SIGMA(+); SYSTEM; RATES; STATE; V'=1; HO2 AB Vibrational energy transfer (VET) v'=1 --> 0 and electronic quenching of v'=1 and 0 in the A (2)Sigma(+) electronically excited state of the OH radical has been studied over the temperature range 195 to 295 K. The colliders investigated were N-2, O-2, and CO2. Laser-induced fluorescence experiments were conducted in a flow cell with photolytic production of OH; both fluorescence intensity and time decay measurements were made. The VET cross sections are found to increase with decreasing temperature, suggestive of attractive force interactions in the VET process. (C) 2000 American Institute of Physics. [S0021-9606(00)00612-7]. C1 SRI Int, Mol Phys Lab, Menlo Park, CA 94025 USA. RP Steffens, KL (reprint author), NIST, 100 Bur Dr,Stop 8362, Gaithersburg, MD 20899 USA. NR 36 TC 14 Z9 14 U1 2 U2 8 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD JUN 1 PY 2000 VL 112 IS 21 BP 9427 EP 9432 DI 10.1063/1.481562 PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 315YC UT WOS:000087139700027 ER PT J AU Kirklin, DR AF Kirklin, DR TI Enthalpy of combustion of acetylsalicylic acid SO JOURNAL OF CHEMICAL THERMODYNAMICS LA English DT Article DE acetylsalicylic acid; aspirin; bomb calorimetry; enthalpy of combustion; enthalpy of formation AB The massic energy of combustion of crystalline acetylsalicylic acid was determined in an NIST adiabatic-aneroid-rotation bomb calorimeter The standard molar enthalpy of combustion at T = 298.15 K and p(o) = 10(5) Pa is Delta(c)H(m)(o)(C9H8O4, cr, 298.15 K) = -(3926.71 +/- 0.34) kJ . mol(-1) The derived standard molar enthalpy of formation is Delta(f)H(m)(o)(C9H8O4, cr, 298.15 K) - (758.19 +/- 0.52) kJ . mol(-1). The molar enthalpy of fusion Delta(fus)H(m)(o)(C9H8O4, cr, 414.0 K) = (29.80 +/- 0.22) kJ . mol(-1) was determined by differential scanning calorimetry. The molar Kirchhoff relationship, d(Delta H) = Delta C(p)dT, was used to convert this value to T = 298.15 K, Delta(fus)H(m)(o)(C9H8O4, cr, 298.15 K) = (19.28 +/- 0.22) KJ . mol(-1). The molar enthalpy of vaporization was estimated using the group contribution scheme of Lebedev and Miroshnichenko. The molar enthalpy of vaporization of acetylsalicyclic acid was estimated as Delta(vap)H(m)(o)(C9H8O4, cr, 298.15 K) = (106.4 +/- 2.0) kJ . mol(-1) The molar enthalpies of fusion and vaporization were used to calculate enthalpies of formation for the liquid and gaseous states of acetylsalicyclic acid, Delta(f)H(m)(o)(C9H8O4, 1, 298.15 K) = -(738.91 +/- 0.56) kJ . mol(-1) and Delta(f)H(m)(o)(C9H8O4, g, 298.15 K) = - (632.5 +/- 2.1) kJ . mol(-1), respectively. (C) 2000 Academic Press. C1 NIST, Chem Sci & Technol Lab, Chem & Phys Properties Div, Gaithersburg, MD 20899 USA. RP Kirklin, DR (reprint author), NIST, Chem Sci & Technol Lab, Chem & Phys Properties Div, Gaithersburg, MD 20899 USA. NR 19 TC 14 Z9 14 U1 0 U2 5 PU ACADEMIC PRESS LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 0021-9614 J9 J CHEM THERMODYN JI J. Chem. Thermodyn. PD JUN PY 2000 VL 32 IS 6 BP 701 EP 709 DI 10.1006/jcht.1999.0650 PG 9 WC Thermodynamics; Chemistry, Physical SC Thermodynamics; Chemistry GA 333KN UT WOS:000088129600001 ER PT J AU Vecchi, GA Harrison, DE AF Vecchi, GA Harrison, DE TI Tropical Pacific sea surface temperature anomalies, El Nino, and equatorial westerly wind events SO JOURNAL OF CLIMATE LA English DT Article ID LOCAL OCEAN RESPONSE; TOGA COARE; SOUTHERN OSCILLATION; DYNAMIC-RESPONSE; WARM POOL; BURST; VARIABILITY; ONSET; WAVES; HEAT AB The authors examine global statistical relationships between westerly wind events (WWEs) and sea surface temperature anomaly (SSTA) variability, using a compositing technique for the period 1986-98, The authors describe the extent to which equatorial WWEs are associated with central and eastern equatorial Pacific waveguide warming and with local SSTA changes under the WWE. Their goal is to quantify the extent to which equatorial WWEs are fundamental to the onset and maintenance of warm El Nino-Southern Oscillation conditions. In order to understand the effect of WWEs on SSTA evolution, they begin by examining how SSTA changes in the absence of equatorial WWEs. They find that SSTA tends toward mean climate values in the absence of equatorial WWEs, whether the eastern equatorial Pacific has close to normal SSTA or warmer than normal SSTA. The two equatorial WWE types whose main surface wind anomalies are west of the date line are associated with weak local surface cooling. The equatorial WWE type that has equatorial westerly wind anomalies east of the date line is associated with weak warming under those anomalies, when the eastern equatorial Pacific SSTA is close to normal. When the tropical Pacific has near-normal eastern equatorial Pacific SST, each of the equatorial WWE types is followed by substantial equatorial waveguide warming in the central and eastern Pacific (composite warming as large as 1.0 degrees C); also more than 50% of the large-amplitude WWEs were followed by Nino-3 SSTA warming in excess of 0.5 degrees C. These changes are of similar amplitude and spatial structure as those seen in the onset of El Nino and are consistent with the predicted oceanic response to WWE forcing. When the eastern equatorial Pacific is initially warmer than usual, the two westernmost equatorial WWE types are associated with the maintenance of warm Fl Nino eastern and central Pacific SSTA; these warm anomalies tend to disappear in the absence of those WWE types. WWEs, or some mechanism strongly correlated with WWEs, represent a fundamental process for waveguide warming in the onset of El Nino and for eastern and central Pacific warm SSTA maintenance during El Nino. C1 Univ Washington, Sch Oceanog, Seattle, WA 98195 USA. Univ Washington, Joint Inst Study Atmosphere & Ocean, Seattle, WA 98195 USA. NOAA, Pacific Marine Environm Lab, OCRD, Seattle, WA 98115 USA. RP Vecchi, GA (reprint author), NOAA, Pacific Marine Environm Lab, OCRD, 7600 Sand Point Way Ne, Seattle, WA 98115 USA. RI Vecchi, Gabriel/A-2413-2008; Harrison, Don/D-9582-2013 OI Vecchi, Gabriel/0000-0002-5085-224X; NR 50 TC 105 Z9 108 U1 1 U2 10 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 JUN 1 PY 2000 VL 13 IS 11 BP 1814 EP 1830 DI 10.1175/1520-0442(2000)013<1814:TPSSTA>2.0.CO;2 PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 322WT UT WOS:000087532800002 ER PT J AU Groisman, PY Bradley, RS Sun, BM AF Groisman, PY Bradley, RS Sun, BM TI The relationship of cloud cover to near-surface temperature and humidity: Comparison of GCM simulations with empirical data SO JOURNAL OF CLIMATE LA English DT Article ID GENERAL-CIRCULATION MODELS; BUDGET EXPERIMENT DATA; FORMER SOVIET-UNION; SNOW COVER; INTERCOMPARISON PROJECT; CLIMATE MODELS; HEAT-BALANCE; RADIATION; EARTH; CLEAR AB One of the possible ways to check the adequacy of the physical description of meteorological elements in global climate models (GCMs) is to compare the statistical structure of these elements reproduced by models with empirical data from the world climate observational system. The success in GCM development warranted a further step in this assessment. The description of the meteorological element in the model can be considered adequate if, with a proper reproduction of the mean and variability of this element (as shown by the observational system), the model properly reproduces the internal relationships between this element and other climatic variables (as observed during the past several decades). Therefore, to distinguish more reliable models, the authors suggest first analyzing these relationships, "the behavior of the climatic system," using observational data and then testing the GCMs' output against this behavior. In this paper, the authors calculated a set of statistics from synoptic data of the past several decades and compared them with the outputs of seven GCMs participating in the Atmospheric Model Intercomparison Project (AMIP), focusing on cloud cover, one of the major trouble spots for which parameterizations are still not well established, and its interaction with other meteorological fields. Differences between long-term mean values of surface air temperature and atmospheric humidity for average and clear sky or for average and overcast conditions characterize the long-term noncausal associations between these two elements and total cloud cover. Not all the GCMs reproduce these associations properly. For example, there was a general agreement in reproducing mean daily cloud-temperature associations in the cold season among all models tested, but large discrepancies between empirical data and some models are found for summer conditions. A correct reproduction of the diurnal cycle of cloud-temperature associations in the warm season is still a major challenge for two of the GCMs that were tested. C1 Univ Massachusetts, Dept Geosci, Amherst, MA 01003 USA. RP Groisman, PY (reprint author), Natl Climat Data Ctr, 151 Patton Ave, Asheville, NC 28801 USA. RI Sun, Bomin/P-8742-2014 OI Sun, Bomin/0000-0002-4872-9349 NR 48 TC 33 Z9 33 U1 1 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 JUN 1 PY 2000 VL 13 IS 11 BP 1858 EP 1878 DI 10.1175/1520-0442(2000)013<1858:TROCCT>2.0.CO;2 PG 21 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 322WT UT WOS:000087532800005 ER PT J AU von Storch, JS Muller, P Stouffer, RJ Voss, R Tett, SFB AF von Storch, JS Muller, P Stouffer, RJ Voss, R Tett, SFB TI Variability of deep-ocean mass transport: Spectral shapes and spatial scales SO JOURNAL OF CLIMATE LA English DT Article ID THERMOHALINE CIRCULATION; ATMOSPHERE MODEL; CLIMATE MODELS AB This paper studies the variability of deep-ocean mass transport using four 1000-yr integrations performed with coupled general circulation models. Statistics describing the spectral and spatial features are considered. It is shown that these features depend crucially on the time-mean state. For the transport of tropical and subtropical water masses in three of the integrations, the spectral levels continually increase with decreasing frequency and do not show isolated peaks at low frequencies. The slope of the low-frequency spectrum (in a log-log plot) changes with increasing depth. It has values of about 0 near the surface, about -1 at intermediate depth, and about -2 at or near the bottom. The result indicates that the maximal memory timescale for deep-ocean mass transport is longer than a few centuries. The situation is different in the fourth integration, which has a different mean circulation pattern. In this case, the low-frequency spectrum is more or less hat in the tropical and subtropical oceans below 2000-3000 m, indicating weak low-frequency variations. The dominant spatial covariance structures describe an anomalous recirculation of intermediate water masses, which is confined to a large extent to each ocean basin. The spatial scale of the dominant modes is therefore smaller than that of the time-mean circulation. C1 Univ Hamburg, Inst Meteorol, D-21046 Hamburg, Germany. Univ Hawaii, Dept Oceanog, Honolulu, HI 96822 USA. NOAA, Geophys Fluid Dynam Lab, Princeton, NJ USA. German Climate Comp Ctr, Hamburg, Germany. UK Meteorol Off, Hadley Ctr, Bracknell, Berks, England. RP von Storch, JS (reprint author), Univ Hamburg, Inst Meteorol, Bundesstr 55, D-21046 Hamburg, Germany. RI Tett, Simon/B-1504-2013 OI Tett, Simon/0000-0001-7526-560X NR 26 TC 14 Z9 14 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8755 J9 J CLIMATE JI J. Clim. PD JUN 1 PY 2000 VL 13 IS 11 BP 1916 EP 1935 DI 10.1175/1520-0442(2000)013<1916:VODOMT>2.0.CO;2 PG 20 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 322WT UT WOS:000087532800008 ER PT J AU Williams, AB Smith, CR Baco, AR AF Williams, AB Smith, CR Baco, AR TI New species of Paralomis (Decapoda, Anomura, Lithodidae) from a sunken whale carcass in the San Clemente Basin off southern California SO JOURNAL OF CRUSTACEAN BIOLOGY LA English DT Article AB Paralomis manningi, new species, is described and illustrated from two immature males recovered from remains of a whale carcass sunken at a depth of 1,922 m in the San Clemente Basin off southern California. While studying the ecology of whale-fall communities on the California margin with the aid of a remotely operated vehicle, we (CRS and ARE) collected the lithodid specimens from the organic-rich axial skeleton of an 11.7-m long juvenile gray whale, Eschrichtius robustus (Lilljeborg, 1861), that had been experimentally placed at the San Clemente floor for 39 months. In general outline of body, spination, and other ornamentation, the new species seems most closely related to four species of Paralomis that were described and figured by Macpherson (1988): P. pectinata Macpherson, P, serrata Macpherson, P. cristulata Macpherson, and P. africana Macpherson. The closest resemblance is to P. cristulata. A key to identification of these species is abridged from Macpherson (1988). Five species of squat lobsters, Galatheidae, were associated with the whale skeleton; Munidopsis cascadia Ambler, M. yaquiensis Ambler, M. verrilli Benedict, M, quadrata Faxon, and a possibly undescribed species of Munidopsis. C1 Univ Hawaii, Dept Oceanog, Honolulu, HI 96822 USA. Smithsonian Inst, Natl Museum Nat Hist, Natl Marine Fisheries Serv, Systemat Lab, Washington, DC 20560 USA. RP Smith, CR (reprint author), Univ Hawaii, Dept Oceanog, 1000 Pope Rd, Honolulu, HI 96822 USA. NR 10 TC 5 Z9 6 U1 0 U2 2 PU CRUSTACEAN SOC PI SAN ANTONIO PA 840 EAST MULBERRY, SAN ANTONIO, TX 78212 USA SN 0278-0372 J9 J CRUSTACEAN BIOL JI J. Crustac. Biol. PD JUN PY 2000 VL 20 IS 2 SI SI BP 281 EP 285 PG 5 WC Marine & Freshwater Biology SC Marine & Freshwater Biology GA 329AB UT WOS:000087883000030 ER PT J AU Bishop, GA Williams, AB AF Bishop, GA Williams, AB TI Fossil crabs from Tepee Buttes, submarine seeps of the Late Cretaceous Pierre Shale, South Dakota and Colorado, USA SO JOURNAL OF CRUSTACEAN BIOLOGY LA English DT Article ID BIOLOGICAL COMMUNITIES; HYDROTHERMAL VENTS; SUBDUCTION ZONE; DEEP-SEA; DECAPODA; PACIFIC; CARBONATES; CRUSTACEA; SLOPE; FAUNA AB Tepee Buttes are low conical hills which occur in scattered clusters along the strike of the Late Cretaceous Pierre Shale near Pueblo, Colorado, and around the Black Hills of South Dakota, Montana, and Wyoming. These erosional landforms develop around resistant columnar limestone masses thought to have been deposited by warm, methane-rich, submarine springs within relatively homogeneous, less resistant claystones. Origin of the Tepee Buttes is attributed to dewatering of underlying claystones. The submarine springs provided a unique habitat on the Western Interior Cretaceous sea bottom for growth of large populations of the lucinid bivalve, Nymphalucina occidentalis, often preserved in living position in reef-like masses encircling the spring vents. Concentration of abundant biomass immediately around the spring vents formed the basis of communities preserved as the Nymphalucina Assemblage dominated by N. occidentalis, but including ammonoid cephalopods, other bivalved mollusks, gastropods, foraminiferans, and a few decapod crustaceans. Fragments of grounded fossilized gymnosperm and angiosperm wood riddled with Teredo borings are also found on the vent cores. Twenty specimens of decapod crustaceans representing three new species of crabs were collected from Tepee Buttes near Oelrichs and Newell, South Dakota, and collecting near Pueblo, Colorado, yielded specimens belonging to three new species, as well as one specimen of Hoplitocarcinus punctatus. The new taxa include Heus foersteri, new genus and species, Raninella manningi, new species (family Raninidae), and Plagiophthalmus bjorki, new species (family Prosopidae). Descriptions, illustrations, and comparisons of new taxa with previously described members of the family are given. C1 Georgia So Univ, Dept Geol & Geog, Statesboro, GA 30460 USA. Smithsonian Inst, Natl Museum Nat Hist, Natl Marine Fisheries Serv, Systemat Lab, Washington, DC 20560 USA. RP Bishop, GA (reprint author), Georgia So Univ, Dept Geol & Geog, Statesboro, GA 30460 USA. NR 90 TC 13 Z9 13 U1 1 U2 7 PU CRUSTACEAN SOC PI SAN ANTONIO PA 840 EAST MULBERRY, SAN ANTONIO, TX 78212 USA SN 0278-0372 J9 J CRUSTACEAN BIOL JI J. Crustac. Biol. PD JUN PY 2000 VL 20 IS 2 SI SI BP 286 EP 300 PG 15 WC Marine & Freshwater Biology SC Marine & Freshwater Biology GA 329AB UT WOS:000087883000031 ER PT J AU Xu, HHK AF Xu, HHK TI Whisker-reinforced heat-cured dental resin composites: Effects of filler level and heat-cure temperature and time SO JOURNAL OF DENTAL RESEARCH LA English DT Article DE ceramic whisker; filler level; heat cure; reinforcement mechanisms; resin composite; strength; toughness ID MECHANICAL-PROPERTIES; GLASS-CERAMICS; FRACTURE-TOUGHNESS; TENSILE-STRENGTH; RESTORATIONS; MICROSTRUCTURE; INDENTATION; CONVERSION; CROWNS; DAMAGE AB Currently available dental resin composites are inadequate for use in large stress-bearing crown and multiple-unit restorations. The aim of this study was to reinforce heat-cured composites with ceramic whiskers. It was hypothesized that whiskers substantially strengthen heat-cured composites. It was further hypothesized that whisker filler level and heat-cure temperature and time significantly influence composite properties. Silica particles were fused onto the whiskers to facilitate silanization and to roughen the whiskers for improved retention in the matrix. The whisker filler mass fraction was varied from 0% to 79%, the heat-cure temperature from 80 degrees C to 180 degrees C, and cure time from 10 min to 24 hrs. Flexural strength, work-of-fracture, and fracture toughness of the composites were measured, and specimen fracture surfaces were examined with scanning electron microscopy. Filler level had a significant effect on composite properties. The whisker composite with 70% filler level had a flexural strength in MPa (mean +/- SD; n = 6) of 248 +/- 23, significantly higher than 120 +/- 16 of an inlay/onlay composite control and 123 +/- 21 of a prosthetic composite control (Tukey's multiple comparison test; family confidence coefficient = 0.95). Heat-cure time also played a significant role. At 120 degrees C, the strength of composite cured for 10 min was 178 +/- 17, lower than 236 +/- 14 of composite cured for 3 hrs. The strength of whisker composite did not degrade after water-aging for 100 d. In conclusion, heat-cured composites were substantially reinforced with whiskers. The reinforcement mechanisms appeared to be whiskers bridging and resisting cracks. The strength and fracture toughness of whisker composite were nearly twice those of currently available inlay/onlay and prosthetic composites. C1 Natl Inst Stand & Technol, Amer Dent Assoc Hlth Fdn, Paffenbarger Res Ctr, Gaithersburg, MD 20899 USA. RP Xu, HHK (reprint author), Natl Inst Stand & Technol, Amer Dent Assoc Hlth Fdn, Paffenbarger Res Ctr, Bldg 224,Room A-153,100 Bur Dr Stop 8546, Gaithersburg, MD 20899 USA. FU NIDCR NIH HHS [R29 DE12476] NR 39 TC 25 Z9 31 U1 0 U2 1 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 JUN PY 2000 VL 79 IS 6 BP 1392 EP 1397 PG 6 WC Dentistry, Oral Surgery & Medicine SC Dentistry, Oral Surgery & Medicine GA 325TZ UT WOS:000087693600007 PM 10890718 ER PT J AU Hard, JJ Connell, L Hershberger, WK Harrell, LW AF Hard, JJ Connell, L Hershberger, WK Harrell, LW TI Genetic variation in mortality of chinook salmon during a bloom of the marine alga Heterosigma akaskiwo SO JOURNAL OF FISH BIOLOGY LA English DT Article DE heritability; effective size; natural selection; HAB ID AKASHIWO RAPHIDOPHYCEAE; FAMILY-SIZE; RED TIDE; BAY; SURVIVAL; JAPAN AB Mortality in a netpen-reared population of 3-year-old chinook salmon Oncorhynchus tshawytscha during an extensive 1997 bloom of the alga Heterosigma akashiwo in Puget Sound, Washington, was low (7.2%), and corresponded to a reduction in variance effective population size of 9.4%. Under a liability threshold model, the heritability of mortality ( +/- S.E.), based on paternal half-sibs, was estimated at 0.15 +/- 0.04. No significant genetic variation was detected for date of death. Despite the low overall mortality, the consequences for variation in family size underscore the importance of maximizing genetic variation in cultured fish populations later released to the wild as a precaution against mortality and losses of genetic variation over the life cycle. The pattern of family variation in response to this algal bloom provides evidence for potentially selective mortality of anadromous salmonids in the marine environment during natural perturbations. C1 NOAA, Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, Conservat Biol Div, Seattle, WA 98112 USA. NOAA, Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, Environm Conservat Div, Seattle, WA 98112 USA. Univ Washington, Sch Fisheries WH10, Seattle, WA 98195 USA. Natl Marine Fisheries Serv, Manchester Marine Expt Stn, Resource Enhancement & Utilizat Technol Div, Manchester, WA 98353 USA. RP Hard, JJ (reprint author), NOAA, Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, Conservat Biol Div, 2725 Montlake Blvd E, Seattle, WA 98112 USA. EM jeff.hard@noaa.gov RI Hard, Jeffrey/C-7229-2009 NR 42 TC 22 Z9 23 U1 1 U2 6 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 0022-1112 J9 J FISH BIOL JI J. Fish Biol. PD JUN PY 2000 VL 56 IS 6 BP 1387 EP 1397 DI 10.1006/jfbi.2000.1258 PG 11 WC Fisheries; Marine & Freshwater Biology SC Fisheries; Marine & Freshwater Biology GA 331WG UT WOS:000088041200008 ER PT J AU Seo, DJ Breidenbach, J Fulton, R Miller, D O'Bannon, T AF Seo, DJ Breidenbach, J Fulton, R Miller, D O'Bannon, T TI Real-time adjustment of range-dependent biases in WSR-88D rainfall estimates due to nonuniform vertical profile of reflectivity SO JOURNAL OF HYDROMETEOROLOGY LA English DT Article ID MEAN-FIELD BIAS; RADAR REFLECTIVITY; INVERSE METHOD; PRECIPITATION; IDENTIFICATION; STORM AB A procedure for real-time adjustment of range-dependent biases in Weather Surveillance Radar-1988 Doppler version (WSR-88D) rainfall estimates due to nonuniform vertical profile of reflectivity is proposed. Using volume-scan measurements of effective reflectivity, the procedure estimates conditional mean and variance profiles of point reflectivity in the vertical and calculates, as a function of elevation angle and slant range, a multiplicative adjustment factor to be applied to the apparent radar rain rate. As a by-product, the maximum effective coverage of radar is also delineated, outside of which radar rainfall estimates are subject to beam overshooting. To evaluate the procedure, unadjusted and adjusted radar rainfall estimates from a Pacific Northwest winter storm are examined and compared with rain gauge data. C1 Natl Weather Serv, Hydrol Res Lab, Silver Spring, MD 20910 USA. WSR 88D Operat Support Facil, Applicat Branch, Norman, OK USA. RP Seo, DJ (reprint author), Natl Weather Serv, Hydrol Res Lab, W-OH1,1325 EW Highway, Silver Spring, MD 20910 USA. NR 29 TC 87 Z9 89 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 1525-755X J9 J HYDROMETEOROL JI J. Hydrometeorol. PD JUN PY 2000 VL 1 IS 3 BP 222 EP 240 DI 10.1175/1525-7541(2000)001<0222:RTAORD>2.0.CO;2 PG 19 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 357DM UT WOS:000089483300003 ER PT J AU Bendersky, LA Maier, R Cohn, JL Neumeier, JJ AF Bendersky, LA Maier, R Cohn, JL Neumeier, JJ TI Structural studies of pulsed-laser-deposited Ba4Fe4Ti3O16 oxide films SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID BATIO3 THIN-FILMS; MICROSTRUCTURE; SYSTEM; SRTIO3 AB For this paper the pulsed laser deposition on single-crystal MgO substrates of Ba4Fe4Ti3O16 target was studied by transmission electron microscopy and x-ray diffraction, The initial stage of the deposition resulted in the formation of the perovskite Ba(Fe,Ti)O-3 phase in an epitaxial, cube-on-cube orientation relationship with a substrate. Further growth of the pseudo-cubic phase was interrupted by the formation of oriented grains with a disordered structure. This disordered structure had a mixture of lamellae of the cubic and hexagonal Ba(Fe,Ti)O-3 phases. No formation of the Ba4Fe4Ti3O16 (E) phase was observed. Formation of the disordered phase was explained by the higher stability of hexagonal Ba(Fe,Ti)O-3 where accommodation of Fe3+ occurred on a twinning plane. The development of the V-shape morphology and a limited number of orientations of the D structure were explained by the faceting and columnar morphology of the perovskite phase. C1 Natl Inst Stand & Technol, Mat Sci & Engn Lab, Gaithersburg, MD 20899 USA. Univ Miami, Dept Phys, Coral Gables, FL 33124 USA. Florida Atlantic Univ, Dept Phys, Boca Raton, FL 33431 USA. RP Bendersky, LA (reprint author), Natl Inst Stand & Technol, Mat Sci & Engn Lab, Gaithersburg, MD 20899 USA. NR 18 TC 4 Z9 4 U1 0 U2 4 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 JUN PY 2000 VL 15 IS 6 BP 1389 EP 1396 DI 10.1557/JMR.2000.0201 PG 8 WC Materials Science, Multidisciplinary SC Materials Science GA 320BY UT WOS:000087382200027 ER PT J AU Ravikiran, A AF Ravikiran, A TI Effect of sliding conditions on formation of grain-pits due to wear anisotropy SO JOURNAL OF MATERIALS SCIENCE LETTERS LA English DT Article C1 Univ Karlsruhe, Inst Mat Sci 2, D-76021 Karlsruhe, Germany. Forschungszentrum Karlsruhe, Inst Mat Res 1, D-76021 Karlsruhe, Germany. RP Ravikiran, A (reprint author), Natl Inst Stand & Technol, Div Ceram, 100 Bur Dr, Gaithersburg, MD 20899 USA. NR 4 TC 3 Z9 3 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0261-8028 J9 J MATER SCI LETT JI J. Mater. Sci. Lett. PD JUN PY 2000 VL 19 IS 12 BP 1041 EP 1043 DI 10.1023/A:1006739003447 PG 3 WC Materials Science, Multidisciplinary SC Materials Science GA 324HB UT WOS:000087614800008 ER PT J AU Lafferty, WJ Flaud, JM Sams, RL Blake, TA Sharpe, SW AF Lafferty, WJ Flaud, JM Sams, RL Blake, TA Sharpe, SW TI High-resolution infrared spectrum of the ring-puckering band, nu(10), of diborane SO JOURNAL OF MOLECULAR SPECTROSCOPY LA English DT Article AB The spectrum of the nu(10) band of diborane, arising from the ring-puckering vibration, has been obtained with a spectral resolution of 0.0015 cm(-1) in the region 275-400 cm(-1). The spectrum of a sample enriched in B-10 was recorded as well as one with naturally abundant boron, i.e., 64% (B2H6)-B-11, 32% (BBH6)-B-10-B-11, and 4% (B2H6)-B-10. This mode is the lowest vibrational level of the molecule and is unperturbed, allowing a complete assignment of not only the fundamental bands but also the 2 nu(10)-nu(10) hot bands of all three boron isotopomers. The intensities of several hundred Lines of the fundamental and hot bands of all isotopomers have been measured and vibrational transition moments have been obtained. Finally, it has been shown that the harmonic approximation does not apply for nu(10). (C) 2000 Academic Press. C1 Natl Inst Stand & Technol, Opt Technol Div, Gaithersburg, MD 20899 USA. Univ Paris 11, CNRS, Photophys Mol Lab, F-91405 Orsay, France. Pacific NW Lab, Richland, WA 99352 USA. RP Lafferty, WJ (reprint author), Natl Inst Stand & Technol, Opt Technol Div, Gaithersburg, MD 20899 USA. NR 10 TC 4 Z9 4 U1 0 U2 0 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 JUN PY 2000 VL 201 IS 2 BP 285 EP 291 DI 10.1006/jmsp.2000.8095 PG 7 WC Physics, Atomic, Molecular & Chemical; Spectroscopy SC Physics; Spectroscopy GA 317RC UT WOS:000087239900010 ER PT J AU Brown, SS Wilson, RW Ravishankara, AR AF Brown, SS Wilson, RW Ravishankara, AR TI Absolute intensities for third and fourth overtone absorptions in HNO3 and H2O2 measured by cavity ring down spectroscopy SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID CROSS-SECTIONS; NITRIC-ACID; INITIATED DECOMPOSITION; UNIMOLECULAR REACTIONS; VIBRATIONAL OVERTONES; DOWN SPECTROSCOPY; RADICALS; HYDROGEN; TROPOSPHERE; EXCITATION AB Photodissociation of nitric acid and hydrogen peroxide via high-lying O-H overtone absorptions in the visible may act as a source of OH radicals in the atmosphere. We have used cavity ring down spectroscopy to measure the absorption cross sections for the third (4 nu(OH)) and fourth (5 nu(OH)) overtone transitions in these molecules. The integrated cross sections are (2.25 +/- 0.15) x 10(-21) and (2.57 +/- 0.24) x 10(-22) cm(2) molecule(-1) cm(-1) for 4 nu(OH) and 5 nu(OH) in nitric acid, respectively, and (4.58 +/- 0.39) x 10(-21) and (5.67 +/- 0.52) x 10(-22) cm(2) molecule(-1) cm(-1) for 4 nu(OH) and 5 nu(OH) in hydrogen peroxide. For both molecules, our report is the first direct intensity measurement for 5 nu(OH). the lowest dissociative overtone transition. We compare our values for the lower overtones to those from previous studies, where available. Our measured cross sections suggest that the contribution of direct overtone excitation to the atmospheric photodissociation of HNO3 and H2O2 is small but not completely negligible. C1 NOAA, Aeron Lab, Boulder, CO 80303 USA. Univ Colorado, Dept Chem & Biochem, Boulder, CO 80309 USA. RP Ravishankara, AR (reprint author), NOAA, Aeron Lab, 325 Broadway,R-AL2, Boulder, CO 80303 USA. RI Brown, Steven/I-1762-2013; Ravishankara, Akkihebbal/A-2914-2011 NR 31 TC 57 Z9 58 U1 0 U2 15 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD JUN 1 PY 2000 VL 104 IS 21 BP 4976 EP 4983 DI 10.1021/jp000439d PG 8 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 320WQ UT WOS:000087424200022 ER PT J AU Rowe, GD Firing, E Johnson, GC AF Rowe, GD Firing, E Johnson, GC TI Pacific equatorial subsurface countercurrent velocity, transport, and potential vorticity SO JOURNAL OF PHYSICAL OCEANOGRAPHY LA English DT Article ID OCEAN; WATER; CIRCULATION AB Concurrent shipboard ADCP and CTD sections are used to calculate the mean velocity, transport, and potential vorticity fields associated with the Pacific equatorial subsurface countercurrents (SCCs). Averaged in stream coordinates, the core eastward velocity of the SCCs is a factor of 2 higher than previously reported means, but the estimated transports are unchanged. The meridional profile of zonal velocity along isopycnals is sharply peaked, and nearly linear on each flank of the current. The sharp and strong reversal of relative vorticity over a distance of 20 km at the jet core sharpens the coincident potential vorticity front. This front separates a region of very low homogeneous potential vorticity on the equatorward side from a homogeneous high potential vorticity region on the poleward side. Each potential vorticity pool extends well beyond the edges of the SCC into regions of westward flow. On the equatorward sides of the SCCs this westward flow is the Equatorial Intermediate Current in the western Pacific, but in the central and eastern parts of the basin it is off the equator in deep extensions of the South Equatorial Current. In the central and eastern regions the net westward transport in an isopycnal layer between the SCCs exceeds the combined eastward SCC transport in that layer. The net zonal transport between the SCC cores is highly divergent in the east and convergent in the west. This pattern, together with downstream changes in SCC density, indicates that neither they nor the westward return Rows are simple inertial recirculations; strong diapycnal processes must be involved. C1 Univ Hawaii Manoa, Honolulu, HI 96822 USA. NOAA, Pacific Marine Environm Lab, Seattle, WA 98115 USA. RP Rowe, GD (reprint author), Accurate Environm Forecasting, 165 Dean Knauss Rd, Narragansett, RI 02882 USA. RI Johnson, Gregory/I-6559-2012 OI Johnson, Gregory/0000-0002-8023-4020 NR 15 TC 50 Z9 50 U1 1 U2 8 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 JUN PY 2000 VL 30 IS 6 BP 1172 EP 1187 DI 10.1175/1520-0485(2000)030<1172:PESCVT>2.0.CO;2 PG 16 WC Oceanography SC Oceanography GA 330KF UT WOS:000087960700003 ER PT J AU Jacob, SD Shay, LK Mariano, AJ Black, PG AF Jacob, SD Shay, LK Mariano, AJ Black, PG TI The 3D oceanic mixed layer response to Hurricane Gilbert SO JOURNAL OF PHYSICAL OCEANOGRAPHY LA English DT Article ID TROPICAL CYCLONES; INTERNAL WAVES; DROPWINDSONDE AB Upper-ocean heat and mass budgets are examined from three snapshots of data acquired during and after the passage of Hurricane Gilbert in the western Gulf of Mexico. Measurements prior to storm passage indicated a warm core eddy in the region with velocities of O(1) m s(-1). Based upon conservation of heat and mass, the three dimensional mixed layer processes are quantified from the data. During and subsequent to hurricane passage, horizontal advection due to geostrophic velocities is significant in the eddy regime, suggesting that prestorm oceanic variability is important when background Rows have the same magnitude as the mixed layer current response. Storm-induced near-inertial currents lead to large vertical advection magnitudes as they diverge from and converge toward the storm track. Surface fluxes, estimated by reducing flight-level winds to 10 m, indicate a maximum wind stress of 4.2 N m(-2) and a heat flux of 1200 W m(-2) in the directly forced region. The upward heat flux after the passage of the storm has a maximum of 200 W m(-2) corresponding to a less than 7 m s(-1) wind speed. Entrainment mixing across the mixed layer base is estimated using three bulk entrainment closure schemes that differ in their physical basis of parameterization. Entrainment remains the dominant mechanism in controlling the heat and mass budgets irrespective of the scheme. Depending on the magnitudes of friction velocity, surface fluxes and/or shear across the mixed layer base, the pattern and location of maximum entrainment rates differ in the directly forced region. While the general area of maximum entrainment is in the right-rear quadrant of the storm, shear-induced entrainment scheme predicts a narrow region of cooling compared to the the stress induced mixing scheme and observed SST decreases. After the storm passage, the maximum contribution to the mixed layer dynamics is associated with shear-induced entrainment mixing forced by near-inertial motions up to the third day as indicated by bulk Richardson numbers that remained below criticality. Thus, entrainment based on a combination of surface fluxes, friction velocity and shear across the entrainment zone may be more relevant for three-dimensional ocean response studies. C1 Univ Miami, Rosenstiel Sch Marine & Atmospher Sci, Div Meteorol & Phys Oceanog, Miami, FL 33149 USA. NOAA, Atlantic Oceanog & Meteorol Lab, Hurricane Res Div, Miami, FL 33149 USA. RP Jacob, SD (reprint author), Univ Miami, Rosenstiel Sch Marine & Atmospher Sci, Div Meteorol & Phys Oceanog, 4600 Rickenbacker Causeway, Miami, FL 33149 USA. NR 45 TC 94 Z9 101 U1 2 U2 10 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 JUN PY 2000 VL 30 IS 6 BP 1407 EP 1429 DI 10.1175/1520-0485(2000)030<1407:TOMLRT>2.0.CO;2 PG 23 WC Oceanography SC Oceanography GA 330KF UT WOS:000087960700016 ER PT J AU Zeisler, R AF Zeisler, R TI Maintaining accuracy in gamma-ray spectrometry at high count rates SO JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY LA English DT Article; Proceedings Paper CT 10th International Conference on Modern Trends in Activation Analysis (MTAA-10) CY APR 19-23, 1999 CL NIH, BETHESDA, MARYLAND SP Natl Inst Stand & Technol HO NIH ID NUCLEAR PULSE SPECTROSCOPY; LOSSES; TIME AB Gamma-ray spectrometry losses through pulse processing dead time and pile-up are best assayed with an external pulse technique. In this work, the virtual pulse generator technique as implemented commercially with the Westphal loss free counting (LFC) module is set up and tested with four high resolution gamma-ray spectrometers. Dual source calibration and decaying source techniques are used in the evaluation of the accuracy of the correction technique. Results demonstrate the reliability of the LFC with a standardized conventional pulse processing system. The accurate correction during high rate counting, including during rapid decay of short lived activities, has been the basis for highly precise determinations in reference materials studies. C1 NIST, Div Analyt Chem, Gaithersburg, MD 20899 USA. RP Zeisler, R (reprint author), NIST, Div Analyt Chem, Gaithersburg, MD 20899 USA. NR 10 TC 13 Z9 13 U1 1 U2 2 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0236-5731 J9 J RADIOANAL NUCL CH JI J. Radioanal. Nucl. Chem. PD JUN PY 2000 VL 244 IS 3 BP 507 EP 510 DI 10.1023/A:1006722729051 PG 4 WC Chemistry, Analytical; Chemistry, Inorganic & Nuclear; Nuclear Science & Technology SC Chemistry; Nuclear Science & Technology GA 338GM UT WOS:000088410800007 ER PT J AU Newbury, DE Wollman, DA Hilton, GC Irwin, KD Bergren, NF Rudman, DA Martinis, JM AF Newbury, DE Wollman, DA Hilton, GC Irwin, KD Bergren, NF Rudman, DA Martinis, JM TI The approaching revolution in X-ray microanalysis: The microcalorimeter energy dispersive spectrometer SO JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY LA English DT Article; Proceedings Paper CT 10th International Conference on Modern Trends in Activation Analysis (MTAA-10) CY APR 19-23, 1999 CL NIH, BETHESDA, MARYLAND SP Natl Inst Stand & Technol HO NIH ID HIGH-RESOLUTION; ELECTROTHERMAL FEEDBACK; DETECTORS AB A high-resolution energy-dispersive X-ray spectrometer (EDS) based on cryogenic microcalorimeter X-ray detectors has been developed for use in X-ray microanalysis. With an energy resolution of 3 eV at 1.5 keV, count rate of similar to 500 s(-1), and an effective collection area of similar to 5 mm(2) (using polycapillary X-ray optics), the microcalorimeter EDS combines many of the favorable qualities of commercially-available wavelength dispersive spectrometers (WDS) and semiconductor EDS. After describing the spectrometer system, we present several applications of microcalorimeter EDS to important microanalysis problems. C1 Natl Inst Stand & Technol, Boulder, CO 80303 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Newbury, DE (reprint author), Natl Inst Stand & Technol, 325 Broadway, Boulder, CO 80303 USA. NR 16 TC 6 Z9 7 U1 1 U2 2 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0236-5731 J9 J RADIOANAL NUCL CH JI J. Radioanal. Nucl. Chem. PD JUN PY 2000 VL 244 IS 3 BP 627 EP 635 DI 10.1023/A:1006777606703 PG 9 WC Chemistry, Analytical; Chemistry, Inorganic & Nuclear; Nuclear Science & Technology SC Chemistry; Nuclear Science & Technology GA 338GM UT WOS:000088410800028 ER PT J AU MacKenzie, CL McLaughlin, SM AF MacKenzie, CL McLaughlin, SM TI Life history and habitat observations of softshell clams Mya arenaria in northeastern New Jersey SO JOURNAL OF SHELLFISH RESEARCH LA English DT Article DE Mya arenaria; settlement densities; survival; mortality factors; growth ID SOFT-SHELL CLAM; CHESAPEAKE BAY; WADDEN SEA; POPULATION-DYNAMICS; BENTHIC MACROFAUNA; RARITAN ESTUARY; FOOD-INTAKE; BLUE CRABS; PREDATION; ABUNDANCE AB Population densities, survival, factors associated with mortalities, and growth of softshell clams, Mya arenaria, in two northeastern New Jersey estuaries were studied from 1993 through 1997. The study areas were near shore where low-tide water depths ranged from 15 to 90 cm. Juvenile densities were high only in 1993. Light sets of juveniles from 1994 to 1997 disappeared by the end of their first summer. The longest living softshells were the abundant 1993 year class, which survived for 26 mo in the Shrewsbury River. This contrasts with life spans of 7-12 years for softshells in New England. Mortalities of softshells were correlated with: (1) predation by the striped killifish, Fundulus majalis, and mummichog, F. heteroclitus; (2) mars of sea lettuce, Ulva lactusa; and (3) high temperatures (30-32 degrees C). Softshell sarcoma was also present and may have contributed to mortalities. The effects of the mortality agents varied among locations and years. The softshells of the Shrewsbury River averaged about 23 mm and 40 mm long at the end of their first and second growing seasons, respectively. C1 NOAA, Natl Marine Fisheries Serv, James J Howard Marine Sci Lab, Highlands, NJ 07732 USA. NOAA, Natl Marine Fisheries Serv, Cooperat Oxford Lab, Oxford, MD 21654 USA. RP MacKenzie, CL (reprint author), NOAA, Natl Marine Fisheries Serv, James J Howard Marine Sci Lab, Highlands, NJ 07732 USA. NR 65 TC 5 Z9 6 U1 1 U2 5 PU NATL SHELLFISHERIES ASSOC PI SOUTHAMPTON PA C/O DR. SANDRA E. SHUMWAY, NATURAL SCIENCE DIVISION, SOUTHAMPTON COLLEGE, SOUTHAMPTON, NY 11968 USA SN 0730-8000 J9 J SHELLFISH RES JI J. Shellfish Res. PD JUN PY 2000 VL 19 IS 1 BP 35 EP 41 PG 7 WC Fisheries; Marine & Freshwater Biology SC Fisheries; Marine & Freshwater Biology GA 342GC UT WOS:000088636000009 ER PT J AU Curtis, KM Trainer, VL Shumway, SE AF Curtis, KM Trainer, VL Shumway, SE TI Paralytic shellfish toxins in geoduck clams (Panope abrupta): Variability, anatomical distribution, and comparison of two toxin detection methods SO JOURNAL OF SHELLFISH RESEARCH LA English DT Article ID POISONING TOXINS AB The geoduck clam, Panope abrupta: is a valuable economic resource in Washington State. Prior to the mid 1970s, the levels of paralytic shellfish poisoning (PSP) toxins in Washington State geoducks were not considered by the Washington State Department of Health (WDOH) to be a risk to public health because the viscera were presumed to be discarded. Recent monitoring information indicates that geoducks accumulate high levels of toxins, primarily in the viscera. The purposes of this study were to determine: (1) the seasonal concentration of paralytic shellfish toxins in geoduck clams at two sites and at two depths within each site; (2) the variability of PSP toxin levels among individual clams within each site; (3) the anatomical distribution of toxins: and (4) the correlation between two methods for estimating PSP toxins. From the summer of 1997 through the winter of 1998, 12-24 geoducks were collected biweekly from a shallow (7 m) and a deep (17 m) location in each of two tracts in Puget Sound, Washington: Quartermaster Harbor (QH) and Agate Pass (AP). Geoducks, dissected into siphon, mantle, and visceral portions, were assayed separately using the mouse bioassay (MBA), while only the visceral portions were assayed using the receptor-binding assay (RBA). Results indicated that toxin variability between individual clams was high in the shallow areas, with coefficients of variation (CVs) ranging from 20-98%, and lower in the deep areas (CV = 18-62%). In QH, only geoducks from the shallow water had toxin levels greater than the regulatory level of 80 mu g saxitoxinequivalents (STX eq) . 100 g shellfish tissue(-1), while all geoducks from AP contained toxin above the regulatory level, with clams from shallow water considerably more toxic than those from deep water. Anatomically, the highest concentrations of PSP toxins were localized in the viscera of geoducks. There was a significant positive correlation between toxin levels measured by the MBA compared to values obtained using the RBA (r(2) = 0.83). The large differences in toxicity between geoducks sampled at different depths and harvest tracts indicate that careful management plans must be designed in order to ensure public health. C1 Jamestown SKiallam Tribe, Dept Nat Resources, Sequim, WA 98382 USA. NOAA, Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, Environm Conservat Div, Seattle, WA 98112 USA. Long Isl Univ, Southampton Coll, Div Nat Sci, Southampton, NY 11968 USA. RP Curtis, KM (reprint author), Jamestown SKiallam Tribe, Dept Nat Resources, Sequim, WA 98382 USA. NR 25 TC 9 Z9 9 U1 0 U2 6 PU NATL SHELLFISHERIES ASSOC PI GROTON PA C/O DR. SANDRA E. SHUMWAY, UNIV CONNECTICUT, 1080 SHENNECOSSETT RD, GROTON, CT 06340 USA SN 0730-8000 J9 J SHELLFISH RES JI J. Shellfish Res. PD JUN PY 2000 VL 19 IS 1 BP 313 EP 319 PG 7 WC Fisheries; Marine & Freshwater Biology SC Fisheries; Marine & Freshwater Biology GA 342GC UT WOS:000088636000048 ER PT J AU McLaughlin, SM Faisal, M AF McLaughlin, SM Faisal, M TI Prevalence of Perkinsus spp. in Chesapeake Bay soft-shell clams, Mya arenaria linnaeus, 1758 during 1990-1998 SO JOURNAL OF SHELLFISH RESEARCH LA English DT Article; Proceedings Paper CT International Conference on Shellfish Restoration CY NOV 18-21, 1998 CL HILTON HEAD ISL, SOUTH CAROLINA DE soft-shell clam; Perkinsus spp.; Chesapeake Bay; Maryland; infection; intensity ID RIBOSOMAL-RNA GENE; SOFTSHELL CLAM; MARINUS AB Prevalence and intensity of Perkinsus spp. infections were determined in soft-shell clams Mya arenaria during 1990 to 1998 based upon incubation of rectal tissues in Ray's fluid thioglycollate medium. During the study, soft-shell clams were collected from 18 sites in the upper Chesapeake Bay in Maryland. Enlarged hypnospores were found in similar to 7% (114/1,705) of the soft-shell clams. Peak prevalences occurred in the fail of 1992 with similar to 53% (16/30) at Piney Point and 50% (15/30) at Eastern Neck, and in August 1995 with similar to 64%(18/28) and similar to 37% (11/30) at Cedar Point and Piney Point, respectively. This investigation provides evidence that Perkinsus spp. infections in soft-shell clams are more common than previously thought. C1 NOAA, Natl Ocean Serv, Ctr Coastal Environm Hlth & Biomol Res, Cooperat Oxford Lab, Oxford, MD 21654 USA. Coll William & Mary, Sch Marine Sci, Virginia Inst Marine Sci, Gloucester Point, VA 23062 USA. RP McLaughlin, SM (reprint author), NOAA, Natl Ocean Serv, Ctr Coastal Environm Hlth & Biomol Res, Cooperat Oxford Lab, 904 S Morris St, Oxford, MD 21654 USA. NR 11 TC 9 Z9 9 U1 0 U2 0 PU NATL SHELLFISHERIES ASSOC PI SOUTHAMPTON PA C/O DR. SANDRA E. SHUMWAY, NATURAL SCIENCE DIVISION, SOUTHAMPTON COLLEGE, SOUTHAMPTON, NY 11968 USA SN 0730-8000 J9 J SHELLFISH RES JI J. Shellfish Res. PD JUN PY 2000 VL 19 IS 1 BP 349 EP 352 PG 4 WC Fisheries; Marine & Freshwater Biology SC Fisheries; Marine & Freshwater Biology GA 342GC UT WOS:000088636000054 ER PT J AU Thode, A Norris, T Barlow, J AF Thode, A Norris, T Barlow, J TI Frequency beamforming of dolphin whistles using a sparse three-element towed array SO JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA LA English DT Article AB Acoustic bearings are obtained from dolphin whistles using frequency-domain (FD) beamforming techniques on signals recorded on a three-element 9-m aperture towed array. Due to the wide element separation, the high-frequency (kHz range) signals generate numerous grating lobes, but these lobes shift bearing with beamformed frequency, allowing identification of the true bearing whenever the whistles have over 1 kHz bandwidth. This method was validated by matching a sighting of a compact group of dolphins with acoustic bearing estimates. The system was subsequently used to detect and determine bearings from animals at least 3 km away and in Beaufort 5+ conditions. Frequency-domain beamforming has advantages over temporal cross correlation when the signals are faint and/or overlapping. (C) 2000 Acoustical Society of America. [S0001-4966(00)00405-7]. C1 Univ Calif San Diego, Scripps Inst Oceanog, Marine Phys Lab, La Jolla, CA 92093 USA. Natl Oceanog & Atmospher Adm, SW Fisheries Sci Ctr, La Jolla, CA 92038 USA. RP Thode, A (reprint author), Univ Calif San Diego, Scripps Inst Oceanog, Marine Phys Lab, La Jolla, CA 92093 USA. NR 9 TC 7 Z9 7 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0001-4966 J9 J ACOUST SOC AM JI J. Acoust. Soc. Am. PD JUN PY 2000 VL 107 IS 6 BP 3581 EP 3584 DI 10.1121/1.429432 PG 4 WC Acoustics; Audiology & Speech-Language Pathology SC Acoustics; Audiology & Speech-Language Pathology GA 322KE UT WOS:000087508100068 PM 10875407 ER PT J AU Lee, SK Tandon, R Readey, MJ Lawn, BR AF Lee, SK Tandon, R Readey, MJ Lawn, BR TI Scratch damage in zirconia ceramics SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Article ID HERTZIAN CONTACT DAMAGE; PARTIALLY-STABILIZED ZIRCONIA; ALUMINA; WEAR; MICROSTRUCTURE; TRANSFORMATION; ACCUMULATION; TRANSITION; FRICTION; FATIGUE AB Scratch damage modes in zirconia-based ceramics-Mg-PSZ, Y-TZP, and Ce-TZP-are investigated, Precursor indentation tests with a tungsten carbide sphere foreshadow the nature of damage: in MO-PSZ, extensive (quasi-)plastic deformation in the region outside and beneath the contact; in Y-TZP, less plastic deformation beneath the contact but incipient cone cracking in the region of tension outside the contact; in Ce-TZP, intermediate behavior. Scratch testing is conducted using a conical diamond indenter. In all materials the damage mode changes from smooth plastic deformation to limited cracking with increasing scratch load: in MB-PSZ, plastic deformation is predominant at lower loads, with microcracking at higher loads; in Y-TZP, plastic deformation is predominant over the range of the test loads-macrocracks initiate only at relatively high loads, but penetrate to a relatively large depth; again, Ce-TZP shows intermediate behavior, but with cracking patterns closer to that of Mg-PSZ, Bending tests on specimens subjected to scratch damage indicate a relatively high damage tolerance in the Mg-PSZ and Ce-TZP; Y-TZP shows the highest initial strength, but suffers relatively large strength loss above the critical load for macrocracking, Implications concerning relative merits of each zirconia type for wear properties, contact fatigue, and machining damage are briefly discussed. C1 Caterpillar Inc, Peoria, IL 61656 USA. NIST, Mat Sci & Engn Lab, Gaithersburg, MD 20899 USA. RP Caterpillar Inc, Peoria, IL 61656 USA. NR 26 TC 31 Z9 31 U1 0 U2 6 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 JUN PY 2000 VL 83 IS 6 BP 1428 EP 1432 PG 5 WC Materials Science, Ceramics SC Materials Science GA 325AW UT WOS:000087655000019 ER PT J AU Yeo, JG Lee, KS Lawn, BR AF Yeo, JG Lee, KS Lawn, BR TI Role of microstructure in dynamic fatigue of glass-ceramics after contact with spheres SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Article ID STRENGTH DEGRADATION; INDENTATION FLAWS; BRITTLE MATERIALS; SILICON-NITRIDE; DAMAGE; DUCTILE AB Dynamic fatigue data are reported for fine- and coarse-grained micaceous glass-ceramics after contact damage with spheres. The strengths of indented specimens are measured at stressing rates from similar to 10(-2) to 10(4) MPa.s(-1) in water. The strength degradation is substantially faster in the coarse-grained structure, and is accelerated further by multicycle contact loading. Failures originate from contact sites in all cases but undergo a progressive transition from classical cone cracks to quasi-plastic microcrack zones with increases in the grain size and the number of contact cycles. The results highlight the particularly deleterious effect of quasi-plastic damage accumulation on lifetime. C1 Natl Inst Stand & Technol, Mat Sci & Engn Lab, Gaithersburg, MD 20899 USA. RP Yeo, JG (reprint author), Natl Inst Stand & Technol, Mat Sci & Engn Lab, Gaithersburg, MD 20899 USA. NR 27 TC 10 Z9 10 U1 0 U2 0 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 JUN PY 2000 VL 83 IS 6 BP 1545 EP 1547 PG 3 WC Materials Science, Ceramics SC Materials Science GA 325AW UT WOS:000087655000042 ER PT J AU Ye, J Ma, LS Hall, JL AF Ye, J Ma, LS Hall, JL TI High-resolution frequency standard at 1030 nm for Yb : YAG solid-state lasers SO JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS LA English DT Article ID SPECTROSCOPY AB A diode-pumped solid-state Yb:YAC laser has been stabilized to a high-finesse cavity with an all-external servo loop. Ultrasensitive cavity-enhanced frequency modulation spectroscopy has recovered a sub-Doppler acetylene overtone transition with a high signal-to-noise ratio, leading to an absorption sensitivity of 7 x 10(-11) at a 1-s averaging time. This high-resolution molecular resonance serves as a long-term stable reference for the laser. The system can be developed into a highly compact and stable optical frequency standard in the 1.03-mu m wavelength range. (C) 2000 Optical Society of America [S0740-3224(00)03206-9]. C1 Natl Inst Stand & Technol, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. Univ Colorado, Boulder, CO 80309 USA. E China Normal Univ, Shanghai 200062, Peoples R China. RP Ye, J (reprint author), Natl Inst Stand & Technol, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. RI Ye, Jun/C-3312-2011 NR 12 TC 23 Z9 23 U1 0 U2 8 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 0740-3224 J9 J OPT SOC AM B JI J. Opt. Soc. Am. B-Opt. Phys. PD JUN PY 2000 VL 17 IS 6 BP 927 EP 931 DI 10.1364/JOSAB.17.000927 PG 5 WC Optics SC Optics GA 322XQ UT WOS:000087534900007 ER PT J AU Evans, DW Kathman, RD Walker, WW AF Evans, DW Kathman, RD Walker, WW TI Trophic accumulation and depuration of mercury by blue crabs (Callinectes sapidus) and pink shrimp (Penaeus duorarum) SO MARINE ENVIRONMENTAL RESEARCH LA English DT Article DE crabs; shrimp; mercury; uptake; depuration; model-bioaccumulation; trophic transfer; assimilation efficiency; biomagnification; Lavaca Bay; Texas ID INORGANIC MERCURY; FOOD; ORGANISMS; BIOACCUMULATION; METHYLMERCURY; MODEL AB Mercury concentrations in blue crabs (Callinectes sapidus) collected from an area of mercury-contaminated sediments in Lavaca Bay, TX, USA, are more than an order of magnitude greater than concentrations in penaeid shrimp from the same area. Laboratory feeding experiments using mercury-contaminated fish as food showed that both blue crabs and pink shrimp (Penaeus duoravum) could accumulate mercury concentrations comparable to those in their food in 28 days. Calculated mercury assimilation efficiencies averaged 76% for blue crabs and 72% for pink shrimp. Significant depuration of mercury by blue crabs was not observed during a subsequent 28-day period, but pink shrimp lost mercury at a rate of about 0.012 day(-1). Model calculations predict biomagnification factors of mercury of about two to three at steady state for both species. The large difference in observed concentrations of mercury in field-collected blue crabs and penaeid shrimp does not result from differences in efficiency of mercury assimilation from their food or from differences in excretion rates. It is more likely the result of differences in residence times in the contaminated area and of differences in feeding habits. Published by Elsevier Science Ltd. C1 NOAA, Natl Ocean Serv, Ctr Coastal Fisheries & Habitat Res, Beaufort, NC 28516 USA. Aquat Resources Ctr, Coll Grove, TN 37046 USA. Univ So Mississippi, Gulf Coast Res Lab, Ocean Springs, MS 39564 USA. RP Evans, DW (reprint author), NOAA, Natl Ocean Serv, Ctr Coastal Fisheries & Habitat Res, 101 Pivers Isl Rd, Beaufort, NC 28516 USA. NR 38 TC 21 Z9 22 U1 2 U2 9 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 JUN PY 2000 VL 49 IS 5 BP 419 EP 434 DI 10.1016/S0141-1136(99)00083-5 PG 16 WC Environmental Sciences; Marine & Freshwater Biology; Toxicology SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Toxicology GA 315CH UT WOS:000087094700002 PM 11285721 ER PT J AU Woody, C Shih, E Miller, J Royer, T Atkinson, LP Moody, RS AF Woody, C Shih, E Miller, J Royer, T Atkinson, LP Moody, RS TI Measurements of salinity in the coastal ocean: A review of requirements and technologies SO MARINE TECHNOLOGY SOCIETY JOURNAL LA English DT Article AB Salinity, a measure of the dissolved salts in seawater, is a fundamental property of seawater and basic to understanding biological and physical processes in coastal waters. In the open ocean long term salinity measurements are identified as necessary to understand global climate studies, hydrological cycle, and circulation. In the coastal oceans, information on salinity is critical to understanding biological effects on ecosystem function such as disease, nursery grounds, or harmful algal blooms and on physical processes such as freshwater runoff estuarine mixing, and coastal currents. While the importance of salinity is recognized, little attention has been given to making routine measurements as to the location and frequency of such measurements. These issues were addressed in a workshop concerned with salinity measurements in coastal oceans, requirements for such, and measurment technology. C1 Natl Ocean & Atmospher Adm, Natl Data Bouy Ctr, Stennis Space Ctr, MS USA. Natl Ocean & Atmospher Adm, Coast Survey Dev Lab, Silver Spring, MD USA. Natl Res Lab, Div Oceanog, Stennis Space Ctr, MS USA. Old Dominion Univ, Ctr Coastal Phys Oceanog, Norfolk, VA USA. RP Woody, C (reprint author), Natl Ocean & Atmospher Adm, Natl Data Bouy Ctr, Stennis Space Ctr, MS USA. NR 24 TC 6 Z9 6 U1 1 U2 2 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 SUM PY 2000 VL 34 IS 2 BP 26 EP 33 PG 8 WC Engineering, Ocean; Oceanography SC Engineering; Oceanography GA 345XD UT WOS:000088839700004 ER PT J AU Yu, CK Smull, BF AF Yu, CK Smull, BF TI Airborne Doppler observations of a landfalling cold front upstream of steep coastal orography SO MONTHLY WEATHER REVIEW LA English DT Article ID MID-LATITUDE CYCLONES; MICROSCALE STRUCTURE; MESOSCALE MOUNTAINS; OLYMPIC MOUNTAINS; RESEARCH AIRCRAFT; SCALE ANALYSIS; PRECIPITATION; RAINBANDS; ORGANIZATION; BARRIER AB This study uses airborne Doppler radar observations to describe the mesoscale structure and evolution of a cold frontal system as it made landfall on the mountainous coast of Oregon and northern California on 1 December 1995 during the Coastal Observations and Simulations with Topography experiment. This section of coastline constitutes a steep, approximately two-dimensional north-south-oriented orographic barrier. The front exhibited a northeast-southwest orientation and thus intersected the axis of high terrain at an acute angle. The along-barrier pressure gradient and low-level winds increased with time along the coastal zone and reached a maximum as the front made landfall. Stably stratified prefrontal Row was strongly blocked by the orography, resulting in a confluent transition from pervasive southwesterly winds offshore to a narrow zone of accelerated south-southwesterly Row near the coast, where wind speeds approached 30 m s(-1) at a height of 750 m above mean sea level. Postfrontal flow was much less affected by the topography, probably because of its weaker static stability. Upstream blocking by the steep coastal terrain also evidently led to modifications of precipitation in the vicinity of the front, including the rapid genesis of a narrow cold-frontal rainband (NCFR) and nearshore enhancement of two prefrontal precipitation bands. This evolution of the NCFR is interpreted in conjunction with changes in prefrontal vertical wind shear, which favored more upright convective ascent as the front neared shore and encountered accelerated along-barrier Row adjacent to the steep terrain. In addition, a statistical examination of observed radar reflectivity patterns shows that the intensity of frontal precipitation systematically decreased with upstream distance away from the orographic barrier. C1 Univ Washington, Dept Atom Sci, Seattle, WA 98195 USA. NOAA, Natl Severe Storms Lab, Seattle, WA USA. RP Smull, BF (reprint author), Univ Washington, JISAO, Box 354235, Seattle, WA 98195 USA. RI Yu, Cheng-Ku/C-3066-2011; OI Yu, Cheng-Ku/0000-0002-5522-4998 NR 52 TC 40 Z9 40 U1 1 U2 6 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 JUN PY 2000 VL 128 IS 6 BP 1577 EP 1603 DI 10.1175/1520-0493(2000)128<1577:ADOOAL>2.0.CO;2 PG 27 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 322WW UT WOS:000087533100001 ER PT J AU Reasor, PD Montgomery, MT Marks, FD Gamache, JF AF Reasor, PD Montgomery, MT Marks, FD Gamache, JF TI Low-wavenumber structure and evolution of the hurricane inner core observed by airborne dual-Doppler radar SO MONTHLY WEATHER REVIEW LA English DT Article ID VORTEX ROSSBY-WAVES; POTENTIAL-VORTICITY; SPIRAL BANDS; BAROTROPIC VORTICES; KINEMATIC STRUCTURE; TROPICAL CYCLONES; VERTICAL SHEAR; INTENSITY; MESOSCALE; AIRCRAFT AB The asymmetric dynamics of the hurricane inner-core region is examined through a novel analysis of high temporal resolution, three-dimensional wind fields derived from airborne dual-Doppler radar. Seven consecutive composites of Hurricane Olivia's (1994) wind field with 30-min time resolution depict a weakening storm undergoing substantial structural changes. The symmetric and asymmetric mechanisms involved in this transformation are considered separately. To zeroth order the weakening of the primary circulation is consistent with the axisymmetric vortex spindown theory of Eliassen and Lystad for a neutrally stratified atmosphere. Vertical shear, however increased dramatically during the observation period, leading to a strong projection of the convection onto an azimuthal wavenumber I pattern oriented along the maximum vertical shear vector. Recent theoretical ideas elucidating the dynamics of vortices in vertical shear are used to help explain this asymmetry. The role of asymmetric vorticity dynamics in explaining some of the physics of hurricane intensify change motivates a special focus on Olivia's vorticity structure. It is found that an azimuthal wavenumber 2 feature dominates the asymmetry in relative vorticity below 3-km height. The characteristics of this asymmetry deduced from reflectivity and wind composites during a portion of the observation period show some consistency with a wavenumber 2 discrete vortex Rossby edge wave. Barotropic instability is suggested as a sourer for the wavenumber 2 asymmetry through a series of barotropic numerical simulations. Trailing bands of vorticity with radial wavelengths of 5-10 km are observed in the inner core approximately 20 km from the storm center, and may be symmetrizing vortex Rossby waves. Elevated reflectivity bands with radial scales comparable to those of the vorticity bands, also near 20-25-km radius, may be associated with these vorticity features. C1 Colorado State Univ, Dept Atmospher Sci, Ft Collins, CO 80523 USA. NOAA, Atlantic Oceanog & Meteorol Lab, Miami, FL 33149 USA. RP Reasor, PD (reprint author), Colorado State Univ, Dept Atmospher Sci, Ft Collins, CO 80523 USA. RI Marks, Frank/A-5733-2011; Gamache, John/A-9702-2014; Reasor, Paul/B-2932-2014 OI Marks, Frank/0000-0003-0371-5514; Gamache, John/0000-0001-5624-0378; Reasor, Paul/0000-0001-6407-017X NR 52 TC 184 Z9 207 U1 1 U2 8 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 JUN PY 2000 VL 128 IS 6 BP 1653 EP 1680 DI 10.1175/1520-0493(2000)128<1653:LWSAEO>2.0.CO;2 PG 28 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 322WW UT WOS:000087533100004 ER PT J AU Shafer, MA MacGorman, DR Carr, FH AF Shafer, MA MacGorman, DR Carr, FH TI Cloud-to-ground lightning throughout the lifetime of a severe storm system in Oklahoma SO MONTHLY WEATHER REVIEW LA English DT Article ID MESOSCALE CONVECTIVE SYSTEMS; KINEMATIC STRUCTURE; RADAR OBSERVATIONS; TORNADIC STORM; THUNDERSTORMS; EVOLUTION; REGION AB Cloud-to-ground (CG) lightning data are examined relative to digitized radar data for a storm system that occurred in Oklahoma on 26 May 1985. This system evolved through three stages: 1) two lines of cells, one near the dryline and the other 60 km ahead of it; 2) a supercell storm; and 3) a mesoscale convective system (MCS). The behavior of lightning in each stage was different. Initially no ground Bashes were observed in either line until reflectivity increased to greater than or equal to 46 dBZ and vertically integrated liquid (VIL) increased to greater than or equal to 10 kg m(-2); then ground Bash rates remained <1.2 min(-1) for >1 h. Most ground flashes in the line of storms near the dryline were negative (18 -CG, 3 +CG), while most in the leading line were positive (11 +CG, 3 -CG), a pattern of polarity opposite to what usually has been observed. Approximately 3 h after radar detected the first storm, ground flash rates increased to >5 min(-1) and remained so for 6 h. A mesocyclone formed approximately 30 min after flash rates exceeded 5 min(-1), and a few positive ground Rashes occurred near it. Ground flash rates increased briefly to >20 min(-1) as the mesocyclone dissipated and then remained >10 min(-1) as a squall line formed along the outflow boundary from the dissipating supercell and produced a stratiform region. Most ground Rashes in this MCS occurred in the convective line and had negative polarity. The few ground flashes in the stratiform region tended to be positive (42 +CG, 32 -CG during 3 h). During 1 h of the MCS, ground Bash rates decreased and then increased again simultaneously in both the convective and stratiform regions, a previously undocumented behavior. It is possible that this was caused by updrafts in both the convective line and stratiform region changing at roughly the same time. It is also possible that most ground flashes in the stratiform region originated near the convective line, and so were influenced by the line. Overall trends in ground flash density, flash relative frequency, reflectivity, VIL, and severe hail reports appeared similar as the storm system evolved. C1 Univ Oklahoma, Sch Meteorol, Norman, OK 73019 USA. Natl Severe Storms Lab, Norman, OK 73069 USA. RP Shafer, MA (reprint author), Oklahoma Climatol Survey, 100 E Boyd,Suite 1210, Norman, OK 73019 USA. NR 36 TC 10 Z9 10 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 JUN PY 2000 VL 128 IS 6 BP 1798 EP 1816 DI 10.1175/1520-0493(2000)128<1798:CTGLTT>2.0.CO;2 PG 19 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 322WW UT WOS:000087533100010 ER PT J AU Lee, WC Marks, FD AF Lee, WC Marks, FD TI Tropical cyclone kinematic structure retrieved from single-Doppler radar observations. Part II: The GBVTD-simplex center finding algorithm SO MONTHLY WEATHER REVIEW LA English DT Article ID VELOCITY TRACK DISPLAY; HURRICANE AB This paper is the second of a series and focuses on developing an algorithm to objectively identify tropical cyclone (TC) vorticity centers using single-Doppler radar data. The first paper dealt with the formulation of a single-Doppler radar TC wind retrieval technique, the ground-based velocity-track-dispiay (GBVTD), and the results are verified using analytical TCs. It has been acknowledged that the quality of the GBVTD-retrieved TC circulation strongly depends on accurately knowing its center position. However, existing single-Doppler radar center finding algorithms are limited to estimate centers for axisymmetric TCs. The proposed algorithm uses a simplex method to objectively estimate the TC vorticity center by maximizing GBVTD-retrieved mean tangential wind. When tested with a number of axisymmetric and asymmetric analytical TCs, the accuracy of the TC centers estimated by the GBVTD-simplex algorithm is approximate to 340 m from the true center. When adding 5 m s(-1) random noise to the Doppler velocities, the accuracy of the TC centers is nearly unchanged at 350 m. When applying the GBVTD-simplex algorithm to Typhoon Alex (1987), the estimated uncertainty varies between 0.1 and 2 km. When the overall velocity gradient is weak, the uncertainties in the retrieved TC centers are usually large. The GBVTD-simplex algorithm sometimes has problems finding a solution when a large sector of Doppler radar data is missing in conjunction with weak velocity gradients. The GBVTD-simplex algorithm significantly reduces the uncertainties in estimating TC center position compared with existing methods and improves the quality of the GBVTD-retrieved TC circulation. The GBVTD-simplex algorithm is computationally efficient and can be easily adapted for real-time applications. C1 Natl Ctr Atmospher Res, Boulder, CO 80307 USA. NOAA, Atlantic Oceanog & Meteorol Lab, Hurricane Res Div, Miami, FL 33149 USA. RP Lee, WC (reprint author), Natl Ctr Atmospher Res, POB 3000, Boulder, CO 80307 USA. RI Marks, Frank/A-5733-2011 OI Marks, Frank/0000-0003-0371-5514 NR 17 TC 40 Z9 49 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 JUN PY 2000 VL 128 IS 6 BP 1925 EP 1936 DI 10.1175/1520-0493(2000)128<1925:TCKSRF>2.0.CO;2 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 322WW UT WOS:000087533100018 ER PT J AU Kamga, AF Fongang, S Viltard, A AF Kamga, AF Fongang, S Viltard, A TI Systematic errors of the ECMWF operational model over tropical Africa SO MONTHLY WEATHER REVIEW LA English DT Article ID DATA ASSIMILATION; FORECAST MODEL; PARAMETERIZATION; VARIABILITY; MASS AB Five-day forecasts using the high-resolution T213L31 Operational Global Spectral Model of the European Centre for Medium-Range Weather Forecasts and associated analyses for summer 1995 are compared in this study to assess the model drift. it is shown here that there is extensive model warming of the lower troposphere especially over the Sahel (+7.5 degrees C) and cooling of the middle troposphere in the tropical Southern Hemisphere. The surface heat wave episode diagnosed by the Climate Prediction Center in summer 1995 was severely overestimated (11 degrees C). A likely cause of this major error is the inaccuracy of convection and boundary layer parameterizations in the case of extreme events. It is found that the model overestimates upper-level subtropical westerlies (+ 3 m s(-1)), low-level monsoon winds, and the Hadley circulation. The African easterly jet is weaker in the model than observed probably because initial easterly zonal wind errors evolve rapidly leading to underestimation of the jet at medium range. It is noteworthy that among climatological features associated with the tropical African summer season, the location and intensity of tropical easterly jet core over West Africa are correctly simulated and no upward shifting of subtropical jets is present in the 5-day forecasts. It is also found that model climatology of geopotential height in the middle troposphere around 700 hPa is relatively free of large-amplitude bias. Suggestions for possible approaches to remove biases are discussed. C1 Ecole Super Polytech, Lab Phys Atmosphere, Dakar, Senegal. CNRS, Meteorol Dynam Lab, Paris, France. RP Kamga, AF (reprint author), NOAA, Ctr Sci, Climate Predict Ctr, W-NP53,Room 800,5200 Auth Rd, Camp Springs, MD 20746 USA. NR 27 TC 10 Z9 10 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 JUN PY 2000 VL 128 IS 6 BP 1949 EP 1959 DI 10.1175/1520-0493(2000)128<1949:SEOTEO>2.0.CO;2 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 322WW UT WOS:000087533100020 ER PT J AU McLaughlin, SM Tall, BD Shaheen, A Elsayed, EE Faisal, M AF McLaughlin, SM Tall, BD Shaheen, A Elsayed, EE Faisal, M TI Zoosporulation of a new Perkinsus species isolated from the gills of the softshell clam Mya arenaria SO PARASITE-JOURNAL DE LA SOCIETE FRANCAISE DE PARASITOLOGIE LA English DT Article DE Perkinsus spp.; softshell clam (Mya arenaria]; zoosporulation; zoospores; ultrastructure ID RIBOSOMAL-RNA GENE; FINE-STRUCTURE; PATINOPECTEN-YESSOENSIS; ATLANTICUS APICOMPLEXA; RUDITAPES-DECUSSATUS; PHYLUM APICOMPLEXA; JAPANESE SCALLOPS; BRITISH-COLUMBIA; OYSTER PATHOGEN; PARASITE AB A gill-associated Perkinsus sp. isolated from the softshell clam (Myo arenaria) is described as a new species, P. chesapeaki sp. nov. Examination of the parasite in seawater cultures revealed life cycle stages and zoosporulation processes similar to those described for other species of the genus Perkinsus. Prezoosporangia developed thickened cell walls upon contraction of the cytoplasm and development of a distinctive clear area between the cell wall and the protoplast. Successive bipartition of the protoplast led to the formation of hundred's of zoospores within mature sporangia. Zoospores were released into seawater through one or more discharge tubes, Ultrastructural studies revealed an oblong zoospore possessing two flagella that arose from a concave side located in the upper third of the zoospore body. The anterior flagellum possessed a unilateral array of hair-like structures. A large anterior vacuole and basolateral nucleus dominated the cytoplasm of the zoospore body. The presence of a rudimentary apical complex including an open-sided conoid, rhoptries, micronemes, and subpellicular microtubules were also discerned. Differences in zoospore morphology, and sequence analyses of two genes previously reported, support the designation of the gill-associated Perkinsus from the softshell clam as a new species. C1 Coll William & Mary, Sch Marine Sci, Virginia Inst Marine Sci, Gloucester Point, VA 23062 USA. NOAA, Natl Ocean Serv, Ctr Coastal Environm Hlth & Biomol Res, Oxford, MD 21654 USA. US FDA, Microbial Ecol Branch, Washington, DC 20204 USA. Fac Vet Med Moshtohor, Benha, Egypt. Cairo Univ, Fac Vet Med, Giza, Egypt. RP Faisal, M (reprint author), Coll William & Mary, Sch Marine Sci, Virginia Inst Marine Sci, Gloucester Point, VA 23062 USA. OI Tall, Ben/0000-0003-0399-3629 NR 29 TC 41 Z9 42 U1 0 U2 4 PU PRINCEPS EDITIONS PI ISSY MOULINEAUX PA 64 AVENUE CHARLES DE GAULLE, 92130 ISSY MOULINEAUX, FRANCE SN 1252-607X J9 PARASITE JI Parasite-J. Soc. Fr. Parasitol. PD JUN PY 2000 VL 7 IS 2 BP 115 EP 122 PG 8 WC Parasitology SC Parasitology GA 324RY UT WOS:000087636200008 PM 10887658 ER PT J AU Tewary, VK AF Tewary, VK TI Lattice-statics model for edge dislocations in crystals SO PHILOSOPHICAL MAGAZINE A-PHYSICS OF CONDENSED MATTER STRUCTURE DEFECTS AND MECHANICAL PROPERTIES LA English DT Article ID GREEN-FUNCTION; METALS AB A semianalytical lattice-statics model is described for calculating the lattice distortion due to an edge dislocation in a crystal lattice to a desired degree of approximation. The edge dislocation is created by introducing a half-plane of vacancies. The defect space is decomposed into a part that has translation symmetry and a localized end space. The displacement field in the translationally symmetric part is calculated in terms of a constant Kanzaki force that is related to the Burgers vector. The Dyson equation for the defect Green's function is then solved by using a matrix partitioning technique in the localized end space. The technique is illustrated by applying it to a sc lattice model. C1 Natl Inst Stand & Technol, Div Mat Reliabil, Boulder, CO 80303 USA. RP Tewary, VK (reprint author), Natl Inst Stand & Technol, Div Mat Reliabil, Boulder, CO 80303 USA. NR 11 TC 5 Z9 5 U1 0 U2 2 PU TAYLOR & FRANCIS LTD PI LONDON PA 11 NEW FETTER LANE, LONDON EC4P 4EE, ENGLAND SN 0141-8610 J9 PHILOS MAG A JI Philos. Mag. A-Phys. Condens. Matter Struct. Defect Mech. Prop. PD JUN PY 2000 VL 80 IS 6 BP 1445 EP 1452 PG 8 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Physics, Applied; Physics, Condensed Matter SC Materials Science; Metallurgy & Metallurgical Engineering; Physics GA 325XP UT WOS:000087702400012 ER PT J AU Liu, WJ Jeng, U Lin, TL Lai, SH Shih, MC Tsao, CS Wang, LY Chiang, LY Sung, LP AF Liu, WJ Jeng, U Lin, TL Lai, SH Shih, MC Tsao, CS Wang, LY Chiang, LY Sung, LP TI Adsorption of dodecahydroxylated-fullerene monolayers at the air-water interface SO PHYSICA B LA English DT Article; Proceedings Paper CT 6th International Conference on X-ray and Neutron Scattering CY SEP 12-17, 1999 CL LEEWENHORST CONGRESS CTR, NOORDWIJKERHOUT, NETHERLANDS SP Leeuwenhorst Congress Ctr, Bruker AXS, Delft Univ, Interfacultair Reactor Inst, Koninklijke Nederlandse Akad VanWetenschappen, Koninklijke Nederlandse Chem Vereniging, Philips Analyt, Stichting Phys HO LEEWENHORST CONGRESS CTR DE fullerene derivatives; monolayer; neutron reflection ID C-60-PROPYLAMINE ADDUCT MONOLAYERS; POLYHYDROXYLATED C-60; DENDRITIC POLYMERS; NEUTRON REFLECTION; LANGMUIR FILMS; ACID AB We study the adsorption behaviors of dodecahydroxylated-fullerene C-60(OH)(12) at the air-water interface. With the hydrophilicity imposed by the 12 hydroxy groups randomly bounded on the C-60 cage, C-60(OH)(12) can dissolve in water slightly. Surface pressure-area isotherms, Brewster angle microscopy, and neutron reflection results for the aqueous solutions of C-60(OH)(12) provide consistent evidence of adsorbed C-60(OH)(12) monolayers at the air-water interface. A Langmuir-Blodgett film of C-60(OH)(12), prepared from the sample solution with the vertical dipping method, is examined using atomic force microscopy. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Natl Tsing Hua Univ, Dept Engn & Syst Sci, Hsinchu 30043, Taiwan. Natl Chung Hsing Univ, Dept Phys, Taichung 402, 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, 101,Sec 2,Kvang Fu Rd, Hsinchu 30043, Taiwan. NR 23 TC 16 Z9 16 U1 3 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4526 J9 PHYSICA B JI Physica B PD JUN PY 2000 VL 283 IS 1-3 BP 49 EP 52 DI 10.1016/S0921-4526(99)01890-6 PG 4 WC Physics, Condensed Matter SC Physics GA 307CF UT WOS:000086635300012 ER PT J AU Borchers, JA Dura, JA Majkrzak, CF Hsu, SY Lolee, R Pratt, WP Bass, J AF Borchers, JA Dura, JA Majkrzak, CF Hsu, SY Lolee, R Pratt, WP Bass, J TI Polarized neutron reflectivity characterization of weakly coupled Co/Cu multilayers SO PHYSICA B LA English DT Article; Proceedings Paper CT 6th International Conference on X-ray and Neutron Scattering CY SEP 12-17, 1999 CL LEEWENHORST CONGRESS CTR, NOORDWIJKERHOUT, NETHERLANDS SP Leeuwenhorst Congress Ctr, Bruker AXS, Delft Univ, Interfacultair Reactor Inst, Koninklijke Nederlandse Akad VanWetenschappen, Koninklijke Nederlandse Chem Vereniging, Philips Analyt, Stichting Phys HO LEEWENHORST CONGRESS CTR DE giant magnetoresistance; magnetic multilayer; off-specular scattering; magnetic domains; polarized neutron reflectivity ID X-RAY; FE/NB MULTILAYERS; SCATTERING; MAGNETORESISTANCE; SUPERLATTICES; FILMS; FE/CR AB Room temperature resistivity studies on (1 1 1) Co(6 nm)/Cu(6 nm) multilayers with weak interlayer coupling yield a giant magnetoresistance (GMR) of several percent for the as-prepared state relative to the saturated (i.e., large magnetic field) state. After application of a magnetic field, the magnetoresistance for the coercive state is only half to two-thirds as large. Using specular and off-specular polarized neutron reflectivity, we have determined the magnetic structure of these multilayers in the as-prepared and coercive states. Measurements of as-prepared samples show a strong antiparallel correlation of in-plane ferromagnetic Co domains across the Cu interlayers. Ar the coercive held, the Co domains are uncorrelated along the growth direction. Thus, the larger GMR for the as-prepared state arises from long-range antiparallel magnetic order along the growth-axis direction that is destroyed upon application of a magnetic field. For both the as-prepared and coercive states. the size of the in-plane ferromagnetic domains is approximately 0.5-1.5 mu m. These domains give rise to pronounced diffuse scattering in rocking curves through the antiferromagnetic peak position. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Natl Inst Stand & Technol, Ctr Neutron Res, Gaithersburg, MD 20899 USA. Michigan State Univ, Dept Phys & Astron, E Lansing, MI 48824 USA. RP Borchers, JA (reprint author), Natl Inst Stand & Technol, Ctr Neutron Res, 100 Bur Dr STOP 8562, Gaithersburg, MD 20899 USA. RI Dura, Joseph/B-8452-2008 OI Dura, Joseph/0000-0001-6877-959X NR 18 TC 11 Z9 11 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4526 J9 PHYSICA B JI Physica B PD JUN PY 2000 VL 283 IS 1-3 BP 162 EP 166 DI 10.1016/S0921-4526(99)01920-1 PG 5 WC Physics, Condensed Matter SC Physics GA 307CF UT WOS:000086635300034 ER PT J AU Majkrzak, CF Berk, NF Silin, V Meuse, CW AF Majkrzak, CF Berk, NF Silin, V Meuse, CW TI Experimental demonstration of phase determination in neutron reflectometry by variation of the surrounding media SO PHYSICA B LA English DT Article; Proceedings Paper CT 6th International Conference on X-ray and Neutron Scattering CY SEP 12-17, 1999 CL LEEWENHORST CONGRESS CTR, NOORDWIJKERHOUT, NETHERLANDS SP Leeuwenhorst Congress Ctr, Bruker AXS, Delft Univ, Interfacultair Reactor Inst, Koninklijke Nederlandse Akad VanWetenschappen, Koninklijke Nederlandse Chem Vereniging, Philips Analyt, Stichting Phys HO LEEWENHORST CONGRESS CTR DE phase determination; inversion AB We have recently shown that it is possible to unambiguously determine the real part of the complex reflection coefficient for a thin film structure by measuring the neutron specular reflectivities for the him in contact with two different backing or two different fronting media, thus simplifying the reference methodology of phase determination and making it more practical. Here we demonstrate the technique in two different experiments. In the first, one backing medium is air, the other, heavy water. In the second, sapphire and silicon serve as two different fronting (incident) media. In addition, we show how the two possible branches of the imaginary part of the reflection coefficient inferred by the real part, while not required for inverting the data to find the film structure, can be a sensitive diagnostic for indicating whether the him of interest is inhomogeneous on a transverse scale comparable to the neutron coherence length. This is especially important in avoiding misinterpretation of data which result from the incoherent average of reflectivities from large-scale heterogeneities. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Natl Inst Stand & Technol, Ctr Neutron Res, Gaithersburg, MD 20899 USA. NIST, Div Biotechnol, Gaithersburg, MD 20899 USA. RP Majkrzak, CF (reprint author), Natl Inst Stand & Technol, Ctr Neutron Res, Gaithersburg, MD 20899 USA. NR 10 TC 23 Z9 24 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4526 J9 PHYSICA B JI Physica B PD JUN PY 2000 VL 283 IS 1-3 BP 248 EP 252 DI 10.1016/S0921-4526(99)01985-7 PG 5 WC Physics, Condensed Matter SC Physics GA 307CF UT WOS:000086635300052 ER PT J AU Copley, JRD Cook, JC AF Copley, JRD Cook, JC TI The optical filter of the disk chopper spectrometer at NIST SO PHYSICA B LA English DT Article; Proceedings Paper CT European Workshop on Neutron Optics for the Next Millennium (NOP 99) CY NOV 25-27, 1999 CL PAUL SCHERRER INST, VILLIGEN, SWITZERLAND SP PSI, FZ Julich, Neutron Round Table HO PAUL SCHERRER INST DE neutron optical filter; time-of-flight spectrometer AB The Disk Chopper Spectrometer at the NIST Center for Neutron Research (NCNR) uses a "neutron optical filter" to remove high-energy neutrons and gamma rays. Nevertheless the measured background at the sample position is time-dependent because of short-wavelength neutrons that get through the optical filter and the choppers. We explain how this happens. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Univ Maryland, Dept Mat & Nucl Engn, College Pk, MD 20742 USA. RP Copley, JRD (reprint author), Natl Inst Stand & Technol, 100 Bur Dr,MS 8562, Gaithersburg, MD 20899 USA. NR 3 TC 4 Z9 4 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4526 J9 PHYSICA B JI Physica B PD JUN PY 2000 VL 283 IS 4 BP 386 EP 388 DI 10.1016/S0921-4526(00)00346-X PG 3 WC Physics, Condensed Matter SC Physics GA 317UU UT WOS:000087246000022 ER PT J AU Ioffe, A AF Ioffe, A TI A new type of high-resolution neutron spectrometer SO PHYSICA B LA English DT Article; Proceedings Paper CT European Workshop on Neutron Optics for the Next Millennium (NOP 99) CY NOV 25-27, 1999 CL PAUL SCHERRER INST, VILLIGEN, SWITZERLAND SP PSI, FZ Julich, Neutron Round Table HO PAUL SCHERRER INST DE high-resolution spectroscopy; interferometer ID SPIN-ECHO AB The movement of a neutron interferometer transverse to the incoming beam produces an interference pattern in velocity space. A change of the neutron velocity due to the scattering in the sample leads to an observable change in the interference pattern. Such a spectrometer has an extremely high-energy resolution approaching the picoelectronvolt region that is a few orders of magnitude higher than the resolution achievable by neutron spin-echo (NSE) spectrometers. Similar to NSE spectrometers, the resolution is not connected with the monochromatization of the incoming beam. However, in contrast to NSE spectrometers the operation of the proposed spectrometer does not necessarily require a polarized neutron beam. By decoupling the polarization and the resolution new possibilities are opened for the study of magnetic phenomena in solids, where the NSE method is principally not applicable because of neutron precession in the sample. The use of the proposed technique in a low-resolution mode can be useful in combination with triple-axis spectrometers allowing a dramatic improvement in their energy resolution without the use of polarized neutrons, and hence avoiding the problem of parasitic magnetic fields. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Univ Missouri, Dept Phys & Astron, Columbia, MO 65211 USA. RP Ioffe, A (reprint author), Hahn Meitner Inst Kernforsch Berlin GmbH, Glienicker Str 100, D-14109 Berlin, Germany. NR 11 TC 0 Z9 0 U1 1 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4526 J9 PHYSICA B JI Physica B PD JUN PY 2000 VL 283 IS 4 BP 406 EP 409 DI 10.1016/S0921-4526(00)00357-4 PG 4 WC Physics, Condensed Matter SC Physics GA 317UU UT WOS:000087246000028 ER PT J AU Ioffe, A AF Ioffe, A TI Triple-axis spectroscopy with sub-mu eV resolution without use of polarized neutrons SO PHYSICA B LA English DT Article; Proceedings Paper CT European Workshop on Neutron Optics for the Next Millennium (NOP 99) CY NOV 25-27, 1999 CL PAUL SCHERRER INST, VILLIGEN, SWITZERLAND SP PSI, FZ Julich, Neutron Round Table HO PAUL SCHERRER INST DE high-resolution spectroscopy; triple-axis spectrometer ID SPIN-ECHO AB We propose a new method that allows for a drastic increase of the resolution of triple-axis spectrometers, up to mu eV/sub-mu eV region. In contrast to neutron spin-echo (NSE)-based methods, the proposed method principally does not require the use of polarized neutrons and is free from problems connected with the mutual influence of the magnetic field of precession coils or with the influence of scattered magnetic fields from the sample environment. Featuring the decoupling of the neutron polarization and energy resolution, the proposed method opens new possibilities for the study of magnetic phenomena in solids, especially by combining the polarization analysis with high-resolution spectroscopy. The proposed method also allows for an easy implementation of the principle of the NSE focusing, when the resolution ellipse is aligned along a dispersion curve. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Univ Missouri, Dept Phys & Astron, Columbia, MO 65211 USA. RP Ioffe, A (reprint author), Hahn Meitner Inst Kernforsch Berlin GmbH, Glienicker Str 100, D-14109 Berlin, Germany. NR 6 TC 2 Z9 2 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4526 J9 PHYSICA B JI Physica B PD JUN PY 2000 VL 283 IS 4 BP 410 EP 413 DI 10.1016/S0921-4526(00)00358-6 PG 4 WC Physics, Condensed Matter SC Physics GA 317UU UT WOS:000087246000029 ER PT J AU Wong-Ng, W Cook, LP Kearsley, A Roosen, A AF Wong-Ng, W Cook, LP Kearsley, A Roosen, A TI Roles of melting equilibria in the processing of high T-c superconductors in the BSCCO system SO PHYSICA C LA English DT Article; Proceedings Paper CT 9th US-Japan Workshop on High-T Superconductors CY OCT 13-15, 1999 CL YAMANASHI, JAPAN SP Forum Superconduct Sci & Technol Japan DE melting equilibria of BSCCO; primary crystallization field; transient liquid; metastable liquid; calculations via web ID PHASE AB Three types of liquids were found in the BSCCO system: transient, metastable and stable. The roles of these liquids are discussed; e.g. the role of metastable liquid in the formation of the (Bi,Pb)-2223 phase, applications of the primary phase field, and the effect of oxygen partial pressure and the presence of Ag on melt formation. (C) 2000 Published by Elsevier Science B.V. C1 Natl Inst Stand & Technol, Div Ceram, US Dept Commerce, Gaithersburg, MD 20899 USA. RP Wong-Ng, W (reprint author), Natl Inst Stand & Technol, Div Ceram, US Dept Commerce, A 256 Matls, Gaithersburg, MD 20899 USA. NR 10 TC 7 Z9 7 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD JUN PY 2000 VL 335 IS 1-4 BP 120 EP 123 DI 10.1016/S0921-4534(00)00155-6 PG 4 WC Physics, Applied SC Physics GA 331YY UT WOS:000088047300026 ER PT J AU Haugan, T Wong-Ng, W Cook, LP Brown, HJ Schwartzendruber, L Shaw, DT AF Haugan, T Wong-Ng, W Cook, LP Brown, HJ Schwartzendruber, L Shaw, DT TI Flux pinning of Bi2Sr2CaCu2O8+delta/Ag superconductors utilizing (Sr,Ca)(14)Cu24O41 defects and nanophase Al2O3 and Au particles SO PHYSICA C LA English DT Article; Proceedings Paper CT 9th US-Japan Workshop on High-T Superconductors CY OCT 13-15, 1999 CL YAMANASHI, JAPAN SP Forum Superconduct Sci & Technol Japan DE Bi2Sr2CaCu2O8+delta; (Sr,Ca)(3)Al2O6; (Sr,Ca)(14)Cu24O41; nanophase Al2O3; nanophase Au; critical current density; flux-pinning ID ADDITIONS; TAPES AB Investigations into flux-pinning of Bi2Sr2CaCu2O8+delta/Ag (Bi-2212/Ag) thick film conductors utilizing micron-sized (Sr,Ca)(14)Cu24O41 and nanophase Al2O3 and Au particles are described. Addition of defect particles delayed and reduced formation of 2212 c-axis texture, while improving film quality by inhibiting Sr:Ca:Cu:O defect formation. Oxide defects were observed to rapidly coarsen in the melt simultaneously with beneficial increase of 2212 texture. Nanophase Al2O3, reacted rapidly (< 4 min) with 2212-type melts (Sr:Ca = 1.33-2.07) to form solid-solution (Sr,Ca)(3)Al2O6 with Sr:Ca ratio close to the Sr:Ca composition of the precursor matrix. Addition of nanophase Al2O3 improved the J(c) (1 T) over the range 20-30 K, e.g. J(c) (30 K, 1 T)/J(c) (5 K, 0 T) = (< 0.001), 0.005, and 0.065 for 0%, 10% and 46% molar addition, respectively. The addition of nanophase or micron-sized Au completely suppressed 2212 c-axis orientation for the processing temperatures tested. (C) 2000 Elsevier Science B.V. All rights reserved. C1 NIST, Mat Sci & Engn Lab, Gaithersburg, MD 20899 USA. SUNY Buffalo, Dept Elect Engn, Amherst, NY 14260 USA. RP Haugan, T (reprint author), NIST, Mat Sci & Engn Lab, 1000 Bur Dr,Stop 8520, Gaithersburg, MD 20899 USA. NR 11 TC 19 Z9 20 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-4534 J9 PHYSICA C JI Physica C PD JUN PY 2000 VL 335 IS 1-4 BP 129 EP 133 DI 10.1016/S0921-4534(00)00157-X PG 5 WC Physics, Applied SC Physics GA 331YY UT WOS:000088047300028 ER PT J AU Kobayashi, R Warren, JA Carter, WC AF Kobayashi, R Warren, JA Carter, WC TI A continuum model of grain boundaries SO PHYSICA D LA English DT Article DE phase field model; grain boundaries; grain rotation; coarsening ID CRYSTALLIZATION; KINETICS; GROWTH AB A two-dimensional frame-invariant phase field model of grain boundaries is developed. One-dimensional analytical solutions for a stable grain boundary in a bicrystal are obtained, and equilibrium energies are computed. With an appropriate choice of functional dependencies; the grain boundary energy takes the same analytic form as the microscopic (dislocation) model of Read and Shockley [W.T. Read, W. Shockley, Phys. Rev. 78 (1950) 275]. In addition, dynamic tone-dimensional) solutions are presented, showing rotation of a small grain between two pinned grains and the shrinkage and rotation of a circular grains embedded in a larger crystal. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Hokkaido Univ, Res Inst Elect Sci, Sapporo, Hokkaido 0600812, Japan. NIST, Div Met, Gaithersburg, MD 20899 USA. NIST, Ctr Theoret & Computat Mat Sci, Gaithersburg, MD 20899 USA. MIT, Dept Mat Sci & Engn, Cambridge, MA 02139 USA. RP Kobayashi, R (reprint author), Hokkaido Univ, Res Inst Elect Sci, Sapporo, Hokkaido 0600812, Japan. RI Carter, W/K-2406-2012 NR 20 TC 170 Z9 172 U1 1 U2 27 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0167-2789 J9 PHYSICA D JI Physica D PD JUN 1 PY 2000 VL 140 IS 1-2 BP 141 EP 150 DI 10.1016/S0167-2789(00)00023-3 PG 10 WC Mathematics, Applied; Physics, Multidisciplinary; Physics, Mathematical SC Mathematics; Physics GA 307CH UT WOS:000086635500007 ER PT J AU Bergeman, T Feder, DL Balazs, NL Schneider, BI AF Bergeman, T Feder, DL Balazs, NL Schneider, BI TI Bose condensates in a harmonic trap near the critical temperature SO PHYSICAL REVIEW A LA English DT Article ID EINSTEIN CONDENSATION; FINITE-TEMPERATURE; ATTRACTIVE INTERACTIONS; TRANSITION-TEMPERATURE; FRACTIONAL-STATISTICS; EXCITED-STATES; GAS; ATOMS; EXCITATIONS; FLUCTUATIONS AB The mean-field properties of finite-temperature Bose-Einstein gases confined in spherically symmetric harmonic traps are surveyed numerically. The solutions of the Gross-Pitaevskii (GP) and Hartree-Fock-Bogoliubov (HFB) equations for the condensate and low-lying quasiparticle excitations are calculated self-consistently using the discrete variable representation, while the most high-lying states are obtained with a local-density approximation. Consistency of the theory for temperatures through the Bose condensation point T-c requires that the thermodynamic chemical potential differ from the eigenvalue of the GP equation; the appropriate modifications lead to results that are continuous as a function of the particle interactions. The HFB equations are made gapless either by invoking the Popov approximation or by renormalizing the particle interactions. The latter approach effectively reduces the strength of the effective scattering length a(sc), increases the number of condensate atoms at each temperature, and raises the value of T-c relative to the Popov approximation. The renormalization effect increases approximately with the log of the atom number, and is most pronounced at temperatures near T-c. Comparisons with the results of quantum Monte Carlo calculations and various local-density approximations are presented, and experimental consequences an discussed. C1 SUNY Stony Brook, Dept Phys, Stony Brook, NY 11794 USA. Univ Oxford, Oxford OX1 3PU, England. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Natl Sci Fdn, Arlington, VA 22230 USA. RP Bergeman, T (reprint author), SUNY Stony Brook, Dept Phys, Stony Brook, NY 11794 USA. NR 57 TC 10 Z9 10 U1 0 U2 3 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 JUN PY 2000 VL 61 IS 6 AR 063605 PG 14 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 323LY UT WOS:000087567900082 ER PT J AU Bruun, GM Clark, CW AF Bruun, GM Clark, CW TI Ideal gases in time-dependent traps SO PHYSICAL REVIEW A LA English DT Article ID BOSE-EINSTEIN CONDENSATE; COLLECTIVE EXCITATIONS; FERMIONIC ATOMS; HARMONIC TRAP; EVOLUTION AB We investigate, theoretically, the properties of an ideal trapped gas in a time-dependent harmonic potential. Using a scaling formalism, we are able to present exact analytical results for two important classes of experiments: free expansion of the gas upon release of the trap and the response of the gas to a harmonic modulation of the trapping potential. We present specific results relevant to current experiments on trapped fermions. C1 US Dept Commerce, Natl Inst Stand & Technol, Div Electron & Opt Phys, Gaithersburg, MD 20899 USA. RP Bruun, GM (reprint author), US Dept Commerce, Natl Inst Stand & Technol, Div Electron & Opt Phys, Gaithersburg, MD 20899 USA. RI Clark, Charles/A-8594-2009 OI Clark, Charles/0000-0001-8724-9885 NR 23 TC 21 Z9 22 U1 0 U2 0 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 JUN PY 2000 VL 61 IS 6 AR 061601 DI 10.1103/PhysRevA.61.061601 PG 4 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 323LY UT WOS:000087567900010 ER PT J AU Tiesinga, E Williams, CJ Mies, FH Julienne, PS AF Tiesinga, E Williams, CJ Mies, FH Julienne, PS TI Interacting atoms under strong quantum confinement SO PHYSICAL REVIEW A LA English DT Article ID BOSE-EINSTEIN CONDENSATE; SCATTERING LENGTHS; OPTICAL LATTICES; PHOTOASSOCIATIVE SPECTROSCOPY; INELASTIC-COLLISIONS; RELAXATION RATES; TRAPPED IONS; COLD; RESONANCE; STATE AB We calculate the energy-level shifts of a tightly confined trapped alkali-metal atom in the presence of a second trapped atom. A complete microscopic description of the interaction energy between the two atoms is used. This allows us to study tightly confined atoms near a Feshbach resonance and to evaluate the usefulness of the regularized delta-function potential approximation. We present results for sodium and cesium when confined in a spherically symmetric harmonic optical trap. Possible implications of the level shifts and collisional decoherence for quantum computing with atomic systems are given. C1 Natl Inst Stand & Technol, Atom Phys Div, Gaithersburg, MD 20899 USA. Univ Maryland, Dept Chem & Biochem, College Pk, MD 20742 USA. RP Tiesinga, E (reprint author), Natl Inst Stand & Technol, Atom Phys Div, Gaithersburg, MD 20899 USA. RI Williams, Carl/B-5877-2009; Julienne, Paul/E-9378-2012 OI Julienne, Paul/0000-0002-5494-1442 NR 50 TC 57 Z9 57 U1 2 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 JUN PY 2000 VL 61 IS 6 AR 063416 DI 10.1103/PhysRevA.61.063416 PG 8 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 323LY UT WOS:000087567900075 ER PT J AU Turchette, QA Kielpinski, D King, BE Leibfried, D Meekhof, DM Myatt, CJ Rowe, MA Sackett, CA Wood, CS Itano, WM Monroe, C Wineland, DJ AF Turchette, QA Kielpinski, D King, BE Leibfried, D Meekhof, DM Myatt, CJ Rowe, MA Sackett, CA Wood, CS Itano, WM Monroe, C Wineland, DJ TI Heating of trapped ions from the quantum ground state SO PHYSICAL REVIEW A LA English DT Article ID ZERO-POINT ENERGY; PAUL TRAP; CONDUCTORS; MOTION; ATOM AB We have investigated motional heating of laser-cooled Be-9(+) ions held in radio-frequency (Paul) traps. We have measured heating rates in a variety of traps with different geometries, electrode materials, and characteristic sizes. The results show that heating is due to electric-field noise from the trap electrodes that exerts a stochastic fluctuating force on the ion. The scaling of the heating rate with trap size is much stronger than that expected from a spatially uniform noise source on the electrodes (such as Johnson noise from external circuits), indicating that a microscopic uncorrelated noise source on the electrodes (such as fluctuating patch-potential fields) is a more likely candidate for the source of heating. C1 Natl Inst Stand & Technol, Div Time & Frequency, Boulder, CO 80303 USA. RP Turchette, QA (reprint author), Res Electroopt, Boulder, CO USA. EM quentint@reoinc.com RI Monroe, Christopher/G-8105-2011 NR 25 TC 303 Z9 305 U1 3 U2 24 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 JUN PY 2000 VL 61 IS 6 AR 063418 DI 10.1103/PhysRevA.61.063418 PG 8 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 323LY UT WOS:000087567900077 ER PT J AU Ye, J Hall, JL AF Ye, J Hall, JL TI Cavity ringdown heterodyne spectroscopy: High sensitivity with microwatt light power SO PHYSICAL REVIEW A LA English DT Article ID OPTICAL-RESONATOR; ABSORPTION AB We present an ac heterodyne technique in cavity ringdown spectroscopy that permits 1 X 10(-10) absorption sensitivity with microwatt-level light power. Two cavity modes, one probing the empty cavity and the other probing intracavity absorption, are excited simultaneously but with their intensities temporally out of phase, with one mode decaying and the other rising. Heterodyne detection between the two modes reveals the dynamic time constants associated with the empty cavity and the additional intracavity gas absorption. The method offers a quick comparison between the on- and off-resonance information, a prerequisite to reaching the fundamental shot-noise limit. This simple and yet important improvement of cavity ringdown spectroscopy should lead to the enhanced performance of a wide range of applications. C1 Natl Inst Stand & Technol, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. Univ Colorado, Boulder, CO 80309 USA. RP Ye, J (reprint author), Natl Inst Stand & Technol, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. EM ye@jila.colorado.edu RI Ye, Jun/C-3312-2011 NR 9 TC 41 Z9 43 U1 1 U2 20 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 JUN PY 2000 VL 61 IS 6 AR 061802 DI 10.1103/PhysRevA.61.061802 PG 4 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 323LY UT WOS:000087567900012 ER PT J AU Lynn, JW Keimer, B Ulrich, C Bernhard, C Tallon, JL AF Lynn, JW Keimer, B Ulrich, C Bernhard, C Tallon, JL TI Antiferromagnetic ordering of Ru and Gd in superconducting RuSr2GdCu2O8 SO PHYSICAL REVIEW B LA English DT Article ID MAGNETIC ORDER; FERROMAGNETISM; COEXISTENCE; ERRH4B4 AB Neutron diffraction has been used to study the magnetic order in RuSr2GdCu2O8. The Ru moments order with the previously reported onset of ferromagnetism. antiferromagnetically at T-N = 136(2) K, coincident Neighboring spins are antiparallel in all three directions, with a low T moment of 1.18(6)mu(B) along the c axis. Our measurements put an upper limit of similar to 0.1 mu(B) to any net zero-field moment, with fields exceeding OAT needed to induce a measurable magnetization. The Gd ions order independently at T-N = 2.50(2) K with the same spin configuration. C1 Natl Inst Stand & Technol, NIST Ctr Neutron Res, Gaithersburg, MD 20899 USA. Max Planck Inst Festkorperforsch, D-70569 Stuttgart, Germany. Ind Res Ltd, Lower Hutt, New Zealand. RP Lynn, JW (reprint author), Natl Inst Stand & Technol, NIST Ctr Neutron Res, Gaithersburg, MD 20899 USA. NR 26 TC 279 Z9 280 U1 0 U2 9 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 JUN 1 PY 2000 VL 61 IS 22 BP 14964 EP 14967 PG 4 WC Physics, Condensed Matter SC Physics GA 325AL UT WOS:000087654100022 ER PT J AU Chopra, HD Yang, DX Chen, PJ Brown, HJ Swartzendruber, LJ Egelhoff, WF AF Chopra, HD Yang, DX Chen, PJ Brown, HJ Swartzendruber, LJ Egelhoff, WF TI Nature of magnetization reversal in exchange-coupled polycrystalline NiO-Co bilayers SO PHYSICAL REVIEW B LA English DT Article ID SYMMETRICAL SPIN-VALVES; GIANT MAGNETORESISTANCE; NIO/NIFE BILAYERS; THIN-FILMS; INTERFACES; MODEL; MULTILAYERS; ANISOTROPY; JUNCTIONS; BIAS AB The nature of magnetization reversal in exchange-coupled NiO-Co polycrystalline bilayers was investigated. As-deposited bilayers exhibit a moderate value of exchange bias Hg (= -0.9 mT) and a significantly enhanced coercivity (H-c(NiO.CO) = 12,4mT), which is roughly 5 times the coercivity of a reference Co single film (H-c(Co) = 2.7 mT). Real time investigation of magnetization reversal in exchange-coupled NiO-Co bilayers shows that reversal is highly local and nonuniform in nature. It is preceded by the formation of precursors or embryos of reversed domains as the applied field reaches a critical value congruent to 8.8-9.0 mT. Once this critical applied field value is reached, numerous reversed domains are formed. Growths of such reversed domains occur primarily by the abrupt nucleation and the subsequent coalescence together of reversed domains; wall motion is not the dominant growth mode. Clear evidence is presented which shows that the strength of exchange bias varies at the microscopic scale across the sample. This manifests itself as different microscopic regions switching abruptly at different fields, and a given microscopic area switching at different fields in the positive and negative field directions. When the applied field is along the unidirectional anisotropy, reversal of a given strongly coupled microscopic region is aided by exchange bias, and such a region switches first; the same region undergoes reversal last when the polarity of the applied field is changed to oppose unidirectional anisotropy. Significantly, it was found that, locally, the measured value of exchange bias may vary by a factor of 3 or more from the macroscopically measured value of H-E (= -0.9 mT) obtained from the shift of the M-H loop. High-resolution transmission electron microscopy (HRTEM) shows that that the local variation in HE may be explained by considering the underlying microstructure and interfacial topography of the NiO-Co interface. HRTEM results show that the NiO surface parallel to the interface may be a fully compensated (200) plane (low H-E), an uncompensated plane (111) (high H-E), or a partially compensated plane (moderate H-E) of antiferromagnetic NiO. Clear evidence of partial compensation of the moments of antiferromagnetic NiO at the interface is found. Partial compensation (and hence a reduced value of H-E) results from a highly faceted NiO surface at the atomic level, with different facets having different orientation (different sublattices). Finally, a magnetic effect is observed, which suggests that it may be energetically more favorable to have steps on the NiO surface that are el en multiples of the unit cell dimensions of NiO ao (= 2ma(0), m epsilon integer > 0) and energetically unfavorable to have steps that are odd multiples of the unit cell dimension a(0) [ = (2m -1)a(0)m epsilon integer > 0]. C1 SUNY Buffalo, Dept Mech & Aerosp Engn, Mat Program, Thin Films & Nanosynth Lab, Buffalo, NY 14260 USA. NIST, Gaithersburg, MD 20899 USA. RP Chopra, HD (reprint author), SUNY Buffalo, Dept Mech & Aerosp Engn, Mat Program, Thin Films & Nanosynth Lab, Buffalo, NY 14260 USA. EM hchopra@eng.buffalo.edu NR 48 TC 45 Z9 46 U1 2 U2 10 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 JUN 1 PY 2000 VL 61 IS 22 BP 15312 EP 15320 DI 10.1103/PhysRevB.61.15312 PG 9 WC Physics, Condensed Matter SC Physics GA 325AL UT WOS:000087654100060 ER PT J AU Kim, YK AF Kim, YK TI Electron correlation in electron-impact ionization of hydrogen-like atoms SO PHYSICS ESSAYS LA English DT Article DE electron-impact ionization; hydrogen-like ions; relativistic cross section ID ENCOUNTER-DIPOLE MODEL; CROSS-SECTIONS; IONS; SCATTERING AB The role of the correlation between the incident and target electrons in electron-impact ionization of hydrogen-like ions is discussed using a simple, analytic cross-section model. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Kim, YK (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NR 22 TC 6 Z9 6 U1 0 U2 0 PU PHYSICS ESSAYS PUBLICATION PI HULL PA C/O ALFT INC, 189 DEVEAULT ST, UNIT NO. 7, HULL, PQ J8Z1S7, CANADA SN 0836-1398 J9 PHYS ESSAYS JI Phys. Essays PD JUN-SEP PY 2000 VL 13 IS 2-3 SI SI BP 473 EP 479 PG 7 WC Physics, Multidisciplinary SC Physics GA 428YT UT WOS:000168489800039 ER PT J AU Sieck, LW Herron, JT Green, DS AF Sieck, LW Herron, JT Green, DS TI Chemical kinetics database and predictive schemes for humid air plasma chemistry. Part I: Positive ion-molecule reactions SO PLASMA CHEMISTRY AND PLASMA PROCESSING LA English DT Article DE plasma; discharge; electron beam; database; ion molecule; kinetic; thermodynamic; rate constant; humid air ID FLOW-DRIFT TECHNIQUE; THERMAL UNIMOLECULAR REACTIONS; RATE CONSTANT MEASUREMENTS; COLLISION RATE CONSTANTS; FALL-OFF RANGE; GAS-PHASE; TEMPERATURE-DEPENDENCE; + H2O; MOBILITY; 300-K AB Reliable kinetic and thermodynamic data are required to model the evolution of electric discharge or electron-beam decomposition chemistry of gases in humid air streams In this first segment of a continuing series, we provide a cove database describing the initially dominant ion-neutral molecule reactions in humid air plasmas. Recommended reaction rate data and extrapolation tools are presented in a manner to facilitate prediction of reactivities and reaction channels as a function of temperature, pressure, and applied electric field. C1 Natl Inst Stand & Technol, Chem Sci & Technol Lab, Gaithersburg, MD 20899 USA. RP Sieck, LW (reprint author), Natl Inst Stand & Technol, Chem Sci & Technol Lab, Gaithersburg, MD 20899 USA. NR 47 TC 35 Z9 35 U1 1 U2 18 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0272-4324 J9 PLASMA CHEM PLASMA P JI Plasma Chem. Plasma Process. PD JUN PY 2000 VL 20 IS 2 BP 235 EP 258 DI 10.1023/A:1007021207704 PG 24 WC Engineering, Chemical; Physics, Applied; Physics, Fluids & Plasmas SC Engineering; Physics GA 326BF UT WOS:000087711500005 ER PT J AU Liu, Y Bhatnagar, A Ji, Q Riffle, JS McGrath, JE Geibel, JF Kashiwagi, T AF Liu, Y Bhatnagar, A Ji, Q Riffle, JS McGrath, JE Geibel, JF Kashiwagi, T TI Influence of polymerization conditions on the molecular structure stability and physical behavior of poly(phenylene sulfide sulfone) homopolymers SO POLYMER LA English DT Article DE poly(phenylene sulfide sulfone); synthesis; transitions AB The influence of polymerization conditions on the nucleophilic substitution step polymerization of high molecular weight poly(phenylene sulfide sulfone) (PPSS) has been studied and optimized with respect to molecular weight for the system 4,4'-dichlorodiphenylsulfone, sodium sulfide, NMP/water/sodium acetate. Reactions at about 200 degrees C for 3 h were observed to produce the highest molecular weight. Longer reaction times and/or higher temperature degrade the molecular weight, probably because of base-catalyzed reactions on the activated backbone. These polymeric materials are amorphous with T-g values up to 222 degrees C. However, the systems show some ordering in the presence of organic liquids, and this allows for an unexpectedly high degree of solvent resistance for molded films. The materials also show a high refractive index of 1.69 and cone calorimetry showed the PPSS system to have very good fire resistance. (C) 2000 Elsevier Science Ltd. All rights reserved. C1 Virginia Polytech Inst & State Univ, Dept Chem, Blacksburg, VA 24061 USA. Virginia Polytech Inst & State Univ, NSF Sci & Technol Ctr, Blacksburg, VA 24061 USA. Phillips Petr Co, Bartlesville, OK 74004 USA. NIST, Bldg & Fire Res Lab, Gaithersburg, MD 20899 USA. RP McGrath, JE (reprint author), Virginia Polytech Inst & State Univ, Dept Chem, Blacksburg, VA 24061 USA. NR 18 TC 36 Z9 44 U1 3 U2 7 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 JUN PY 2000 VL 41 IS 13 BP 5137 EP 5146 DI 10.1016/S0032-3861(99)00571-6 PG 10 WC Polymer Science SC Polymer Science GA 299EB UT WOS:000086181800037 ER PT J AU Kueh, SRM Advani, SG Parnas, RS AF Kueh, SRM Advani, SG Parnas, RS TI Sensor placement study for online flow monitoring in liquid composite molding SO POLYMER COMPOSITES LA English DT Article ID FIBER OPTIC SENSORS; CURE; SPECTROSCOPY; SIMULATION; RESINS; RAMAN AB On-line sensing can play an important part in controlling the quality of the final product in any manufacturing environment, including liquid composite molding (LCM). Having a sensor embedded within the part itself is often the most effective means of monitoring its condition at various stages of manufacturing and even throughout its useful life. However, given their intrusive nature, there are practical Limitations imposed upon their size, quantity and trajectory within the part. This study explores the possibility of using a single Lineal sensor to monitor the resin now front during the mold filling stage of LCM, and to detect the onset of void formation and the presence of dry spots within the mold, Experiments were conducted to characterize the response of a fiber optic system previously developed for cure monitoring. Simulations were then performed to determine the optimal placement of just one such sensor in a mold to demonstrate that sufficient information on the mold filling process could be obtained. The purpose of the simulation work was to learn how to interpret the sensor response and, subsequently, use it to control the LCM process. C1 Univ Delaware, Dept Mech Engn, Newark, DE 19716 USA. Natl Inst Stand & Technol, Div Polymers, Gaithersburg, MD 20899 USA. RP Parnas, RS (reprint author), Natl Inst Stand & Technol, Div Polymers, 100 Bur Dr,Stop 8543, Gaithersburg, MD 20899 USA. NR 47 TC 4 Z9 6 U1 2 U2 5 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 0272-8397 J9 POLYM COMPOSITE JI Polym. Compos. PD JUN PY 2000 VL 21 IS 3 BP 436 EP 449 DI 10.1002/pc.10200 PG 14 WC Materials Science, Composites; Polymer Science SC Materials Science; Polymer Science GA 331UY UT WOS:000088038100009 ER PT J AU Holmes, GA Peterson, RC Hunston, DL McDonough, WG AF Holmes, GA Peterson, RC Hunston, DL McDonough, WG TI E-glass/DGEBA/m-PDA single fiber composites: The effect of strain rate on interfacial shear strength measurements SO POLYMER COMPOSITES LA English DT Article ID STRESS-DISTRIBUTION; MODEL COMPOSITES; MODULUS; SYSTEMS; MATRIX AB Precise measurements of fiber break regions have been made during the single fiber fragmentation test (SFFT) procedure on E-glass/diglycidyl ether of bisphenol-A (DGEBA) /meta-phenylenediamine (m-PDA) test specimens. From these measurements, the location and size of each fiber fragment was determined, and the resulting information was used to construct fragmentation maps of the tested fiber. By comparing these maps, the fragmentation process supports random fragmentation along the length of the fiber. Since the interfacial shear strength (IFSS) or the interfacial shear stress transfer coefficient (I-STC) is obtained from the fragment length data at the end of the test (saturation), frequency histograms of the fragment length data were constructed to determine the repeatability of the fragmentation process. Since the SFFT is performed by sequential step-strains of the test specimen, test protocols were developed by controlling the step size of each strain increment and the time between each step-strain (dwell time). For the testing protocols used in this research. the E-glass/DGEBA/m-PDA frequency histograms of the fragment lengths were found to be generally repeatable. However, when the effective strain rate of the test was altered by changing the dwell time between strain increments, the fragment distribution at saturation of the E-glass/DGEBA/m-PDA SFFT specimens changed. The direction of the change was found to be inconsistent with the effect one might expect when only the nonlinear viscoelastic behavior of the matrix is considered. However, the magnitude of the change observed in the E-glass/DGEBA/m-PDA SFFT specimens is not universal. Fragmentation data obtained on E-glass/polyisocyanurate SFFT specimens revealed a much smaller change in fragment length distributions with the same change in testing protocols. Consistent with the results obtained on the E-glass/DGEBA/m-PDA, fiber fragmentation occurs when the polyisocyanurate matrix exhibits nonlinear viscoelastic behavior. The implication of these results for interfacial shear strength measurements is discussed. C1 Natl Inst Stand & Technol, Div Polymers, Gaithersburg, MD 20899 USA. RP Holmes, GA (reprint author), Natl Inst Stand & Technol, Div Polymers, Gaithersburg, MD 20899 USA. NR 28 TC 21 Z9 21 U1 2 U2 9 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 JUN PY 2000 VL 21 IS 3 BP 450 EP 465 DI 10.1002/pc.10201 PG 16 WC Materials Science, Composites; Polymer Science SC Materials Science; Polymer Science GA 331UY UT WOS:000088038100010 ER PT J AU Mighell, AD AF Mighell, AD TI Lattice metric singularities and their impact on the indexing of powder patterns SO POWDER DIFFRACTION LA English DT Article ID DIFFRACTION PATTERNS AB lattice metric singularity occurs when unit cells defining two (or more) lattices yield the identical set of unique calculated d-spacings. The existence of such singularities, therefore, has a practical impact on the indexing of powder patterns. For example, when experimental data from zeta-LiBO2 were indexed, two solutions (a rhombohedral and a monoclinic lattice) with approximately the same figure of merit were found. These two lattices yield the same set of unique d-spacings even though they are characterized by different reduced cells with cell volumes in the ratio 2 to 1. From the indexing point of view, both answers are correct. A singularity of this type is common and not a mathematical rarity. In fact, any rhombohedral cell of this kind has a derivative monoclinic subcell, each of which gives the same set of unique calculated cl-spacings. In actual cases like this, one can run into a trap. Due to experimental error and input parameters, an indexing program may determine only one of the cells with a high figure of merit. When this happens, it is critical to recognize that another solution exists, especially if one has determined the lower symmetry lattice. (C) 2000 International Centre for Diffraction Data. [S0885-7156(00)00201-3]. C1 Natl Inst Stand & Technol, Mat Sci & Engn Lab, Gaithersburg, MD 20899 USA. RP Mighell, AD (reprint author), Natl Inst Stand & Technol, Mat Sci & Engn Lab, Gaithersburg, MD 20899 USA. NR 12 TC 8 Z9 8 U1 0 U2 2 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0885-7156 J9 POWDER DIFFR JI Powder Diffr. PD JUN PY 2000 VL 15 IS 2 BP 82 EP 85 PG 4 WC Materials Science, Characterization & Testing SC Materials Science GA 326WQ UT WOS:000087760500003 ER PT J AU Mopsik, FI AF Mopsik, FI TI Extended frequency range dielectric measurements of thin films SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article AB A method is described to measure the dielectric constant and loss of thin films. It employs a sample holder based on precision 50 Ohm air line and can be used from audio frequencies to 1 GHz with a single sample. It is shown to maximize the precision available from commercial instrumentation with minimal data correction. This is confirmed by regions in which the different instruments overlap their frequency coverage. [S0034-6748(00)05106-6]. C1 Natl Inst Stand & Technol, Div Polymers, Gaithersburg, MD 20899 USA. RP Mopsik, FI (reprint author), Natl Inst Stand & Technol, Div Polymers, Gaithersburg, MD 20899 USA. NR 4 TC 3 Z9 3 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD JUN PY 2000 VL 71 IS 6 BP 2456 EP 2460 DI 10.1063/1.1150663 PG 5 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 319NV UT WOS:000087348800032 ER PT J AU Doddington, GR Przybocki, MA Martin, AF Reynolds, DA AF Doddington, GR Przybocki, MA Martin, AF Reynolds, DA TI The NIST speaker recognition evaluation - Overview, methodology, systems, results, perspective SO SPEECH COMMUNICATION LA English DT Article; Proceedings Paper CT ESCA Workshop on Speaker Recognition and its Commercial and Forensic Applications (RLA2C) CY APR 20-23, 1998 CL AVIGNON, FRANCE SP ESCA DE speaker recognition; identification; verification; performance evaluation; NIST evaluations; detection error trade-off (DET) curve AB This paper, based on three presentations made in 1998 at the RLA2C Workshop in Avignon, discusses the evaluation of speaker recognition systems from several perspectives. A general discussion of the speaker recognition task and the challenges and issues involved in its evaluation is offered. The NIST evaluations in this area and specifically the 1998 evaluation, its objectives, protocols and test data, are described. The algorithms used by the systems that were developed for this evaluation are summarized, compared and contrasted. Overall performance results of this evaluation are presented by means of detection error trade-off (DET) curves. These show the performance trade-off of missed detections and false alarms for each system and the effects on performance of training condition, test segment duration, the speakers' sex and the match or mismatch of training and test handsets. Several factors that were found to have an impact on performance, including pitch frequency, handset type and noise, are discussed and DET curves showing their effects are presented. The paper concludes with some perspective on the history of this technology and where it may be going. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. SRI Int, Menlo Pk, CA 94025 USA. MIT, Lincoln Lab, Lexington, MA 02173 USA. RP Martin, AF (reprint author), Natl Inst Stand & Technol, Technol Bldg 225, Gaithersburg, MD 20899 USA. EM alvin.martin@nist.gov NR 21 TC 128 Z9 133 U1 1 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0167-6393 EI 1872-7182 J9 SPEECH COMMUN JI Speech Commun. PD JUN PY 2000 VL 31 IS 2-3 BP 225 EP 254 DI 10.1016/S0167-6393(99)00080-1 PG 30 WC Acoustics; Computer Science, Interdisciplinary Applications SC Acoustics; Computer Science GA 329BW UT WOS:000087887100012 ER PT J AU Allen, RH Sriram, RD AF Allen, RH Sriram, RD TI The role of standards in innovation SO TECHNOLOGICAL FORECASTING AND SOCIAL CHANGE LA English DT Article AB We review and explore the role of standards in innovation, with particular emphasis on design and manufacturing processes. We begin by defining and classifying standards and by exploring their role and infrastructure in society. This is followed by a similar discussion for innovation. By examining the relationships between innovation and standards, we extract the negative impact and the positive impact each has on the other. A study of four case histories in different domains-manufacturing, computer hardware, mechanical component design, and product data exchange-reveals that, as expected, standards are often derived from innovative technology. Surprisingly, however, innovation is often spurred-directly and indirectly-from standards as well. We conclude that, in general, the benefits of standards on innovation in design and manufacturing outweigh the possible limitations on creativity imposed by such standards. (C) 2000 Elsevier Science Inc. C1 NIST, Gaithersburg, MD 20899 USA. Univ Maryland, Dept Mech Engn, College Pk, MD 20742 USA. RP Sriram, RD (reprint author), NIST, 100 Bur Dr,Stop 8260, Gaithersburg, MD 20899 USA. EM sriram@cme.nist.gov RI Allen, Robert/A-3731-2010 NR 27 TC 34 Z9 40 U1 0 U2 16 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0040-1625 J9 TECHNOL FORECAST SOC JI Technol. Forecast. Soc. Chang. PD JUN-JUL PY 2000 VL 64 IS 2-3 BP 171 EP 181 DI 10.1016/S0040-1625(99)00104-3 PG 11 WC Business; Planning & Development SC Business & Economics; Public Administration GA 343YB UT WOS:000088729600005 ER PT J AU Hong, JS Kim, D AF Hong, JS Kim, D TI A statistical algorithm for clear-sky temperature and humidity retrievals from TOVS radiance SO TERRESTRIAL ATMOSPHERIC AND OCEANIC SCIENCES LA English DT Article DE TOVS radiance; regression retrieval ID ASSIMILATION; SYSTEM AB In this study a regression algorithm was developed to retrieve the atmospheric parameters from TOVS (TIROS Operational Vertical Sounder) clear-sky radiances. The development of this algorithm requires calculations, at RAOB (RAdiosonde OBservation) sites, of the cross-covariances among fields obtained from rawinsonde observations, satellite radiances, and forecast products. The data were collected in every assimilation cycle for three months from May to August 1997. The retrievals were verified statistically with the co-located RAOB measurements for two periods of experiments. The results show that the bias is comparable to the first guess. Compared with the forecast, the root mean square errors of the retrievals in the troposphere were better by about 1 similar to 1.5 K in temperature and 0.2 similar to 0.4 g/Kg in the mixing ratio. The root mean square error of retrievals at surface showed an improvement of 0.5 similar to 1 K in temperature and 1.5 similar to 2 g/Kg in the mixing ratio. The results during the August period were noticeably better than in the June period. This implies that the retrieved profiles were closer to the RAOB profiles than the 12-hour forecast profiles were. The contour field of the retrievals showed a slight correction on the first guess field both in temperature and the mixing ratio except in the subtropical area. The results are also encouraging in that the retrievals in this case had a local coherence both in the horizontal and vertical. C1 Cent Weather Bur, Ctr Comp, Taipei, Taiwan. Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. NOAA, Forecast Syst Lab, Boulder, CO 80303 USA. RP Hong, JS (reprint author), Cent Weather Bur, Ctr Comp, 64 Kung Yuan Rd, Taipei, Taiwan. EM rfs14@cwb.gov.tw NR 21 TC 0 Z9 0 U1 0 U2 0 PU CHINESE GEOSCIENCE UNION PI TAIPEI PA PO BOX 23-59, TAIPEI 10764, TAIWAN SN 1017-0839 J9 TERR ATMOS OCEAN SCI JI Terr. Atmos. Ocean. Sci. PD JUN PY 2000 VL 11 IS 2 BP 439 EP 458 PG 20 WC Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences; Oceanography SC Geology; Meteorology & Atmospheric Sciences; Oceanography GA 332GF UT WOS:000088065300004 ER PT J AU Rotter, LD Vaudin, MD Bonevich, JE Kaiser, DL Park, SO AF Rotter, LD Vaudin, MD Bonevich, JE Kaiser, DL Park, SO TI Correlation of the optical gap of (Ba,Sr)(y)TiO2+y thin films with film composition SO THIN SOLID FILMS LA English DT Article DE amorphous materials; dielectrics; optical properties; optical spectroscopy; oxides ID HYDROGENATED AMORPHOUS-SILICON; BATIO3; STOICHIOMETRY; SPECTROSCOPY AB A series of 26 (Ba1-xSrx)(y)TiO2+y thin films with 0.22 less than or equal to y less than or equal to 1.01 and x < 0.07 were grown by metalorganic chemical vapor deposition. Most of the films with 0.22 less than or equal to y less than or equal to 0.37 were fully amorphous, whereas the films with 0.43 less than or equal to y < 1 were composed of crystalline (Ba,Sr)-TiO3 and a Ti-rich amorphous phase. Transmission spectra were measured and analyzed to determine the optical constants of the films, including the optical gap, which was found to decrease as y increased. An effective medium model was used to estimate the volume fraction of amorphous material in the two-phase films from the transmission spectra, by assuming that the two phases each had a fixed optical gap. (C) 2000 Elsevier Science S.A. All rights reserved. C1 Natl Inst Stand & Technol, Mat Sci & Engn Lab, Gaithersburg, MD 20899 USA. Samsung Elect Co Ltd, Semicond R&D Ctr, Kyungki, South Korea. RP Rotter, LD (reprint author), Natl Inst Stand & Technol, Mat Sci & Engn Lab, 100 Bur Dr, Gaithersburg, MD 20899 USA. NR 35 TC 6 Z9 6 U1 0 U2 1 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0040-6090 J9 THIN SOLID FILMS JI Thin Solid Films PD JUN 1 PY 2000 VL 368 IS 1 BP 41 EP 48 DI 10.1016/S0040-6090(00)00713-6 PG 8 WC Materials Science, Multidisciplinary; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Materials Science; Physics GA 320RK UT WOS:000087414000007 ER PT J AU Wilson, KB Baldocchi, DD Hanson, PJ AF Wilson, KB Baldocchi, DD Hanson, PJ TI Quantifying stomatal and non-stomatal limitations to carbon assimilation resulting from leaf aging and drought in mature deciduous tree species SO TREE PHYSIOLOGY LA English DT Article DE A/C-i curve; leaf age; maple; oak; photosynthetic limitations; stomata ID NONSTOMATAL LIMITATIONS; CO2 ASSIMILATION; PHOTOSYNTHETIC PARAMETERS; NET PHOTOSYNTHESIS; SEASONAL PATTERNS; WATER-STRESS; CONDUCTANCE; LEAVES; MODEL; OAK AB Gas exchange techniques were used to investigate light-saturated carbon assimilation and its stomatal and nonstomatal limitations over two seasons in mature trees of five species in a closed deciduous forest. Stomatal and non-stomatal contributions to decreases in assimilation resulting from leaf age and drought were quantified relative to the maximum rates obtained early in the season at optimal soil water contents. Although carbon assimilation, stomatal conductance and photosynthetic capacity (V-cmax) decreased with leaf age, decreases in V-cmax accounted for about 75% of the leaf-age related reduction in light-saturated assimilation rates, with a secondary role for stomatal conductance (around 25%). However, when considered independently from leaf age, the drought response was dominated by stomatal limitations, accounting for about 75% of the total limitation. Some of the analytical difficulties associated with computing limitation partitioning are discussed, including path dependence, patchy stomatal closure and diffusion in the mesophyll. Although these considerations may introduce errors in our estimates, our analysis establishes some reasonable boundaries on relative limitations and shows differences between drought and non-drought years. Estimating seasonal limitations under natural conditions, as shown in this study, provides a useful basis for comparing limitation processes between years and species. C1 NOAA, Atmospher Turbulence & Diffus Div, Oak Ridge, TN 37831 USA. Oak Ridge Natl Lab, Div Environm Sci, Oak Ridge, TN 37831 USA. RP Wilson, KB (reprint author), NOAA, Atmospher Turbulence & Diffus Div, POB 2456, Oak Ridge, TN 37831 USA. RI Hanson, Paul J./D-8069-2011; Kodama, Naomi/D-9553-2011; Baldocchi, Dennis/A-1625-2009 OI Hanson, Paul J./0000-0001-7293-3561; Kodama, Naomi/0000-0001-9913-9886; Baldocchi, Dennis/0000-0003-3496-4919 NR 44 TC 108 Z9 112 U1 2 U2 24 PU HERON PUBLISHING PI VICTORIA PA 202, 3994 SHELBOURNE ST, VICTORIA, BC V8N 3E2, CANADA SN 0829-318X J9 TREE PHYSIOL JI Tree Physiol. PD JUN PY 2000 VL 20 IS 12 BP 787 EP 797 PG 11 WC Forestry SC Forestry GA 334RY UT WOS:000088200500002 ER PT J AU Schwartz, BE Benjamin, SG Green, SM Jardin, MR AF Schwartz, BE Benjamin, SG Green, SM Jardin, MR TI Accuracy of RUC-1 and RUC-2 wind and aircraft trajectory forecasts by comparison with ACARS observations SO WEATHER AND FORECASTING LA English DT Article ID SYSTEM; TEMPERATURE; MODEL AB As part of an investigation into terminal airspace productivity sponsored by the NASA Ames Research Center, a study was performed at the Forecast Systems Laboratory to investigate sources of wind forecast error and to assess differences in wind forecast accuracy between the 60-km Rapid Update Cycle, version 1 (RUC-1), and the newer 40-km RUC-2. Improved knowledge of these errors is important for development of air traffic management automation tools under development at NASA Ames and elsewhere. This information is also useful for operational users of RUC forecast winds. To perform this study, commercial aircraft reports of wind reported through Aircraft Communications, Addressing, and Reporting System (ACARS) were collected in a region over the western and central United States for a 13-month period, along with RUC-1 and RUC-2 wind forecasts. Differences between forecasts and ACARS observations and estimates of ACARS wind observation error itself were both calculated. It was found that rms vector differences between observations and forecasts from either version of the RUC increased as wind speed increased, and also as altitude increased and in winter months (both associated with higher wind speed). Wind errors increased when thunderstorms were nearby and were smaller in wintertime precipitation situations. The study also showed that considerable progress has been made in the accuracy of wind forecasts to be used for air traffic management by the introduction of the RUC-2 system, replacing the previous RUC-1 system. Improvement was made both in the intrinsic accuracy as well as in the time availability, both contributing to the overall improvement in the actual wind forecast available for air traffic management purposes. Using 3-h forecasts, RUC-2 demonstrated a reduction in mean daily rms vectors of approximately 10% over that for RUC-1 based on accuracy improvements alone. This error reduction increased to about 22% when time availability improvements were added. it was also found that the degree of improvement from the RUC-2 increased substantially for periods with a large number of significant wind errors. The percentage of individual vector errors greater than 10 m s(-1) was reduced by RUC-2 from 8% (RUC-1) to 3% overall and from 17% to 7% during the worst month. Such peak error periods have a strong impact on air traffic management automation tools. Last, it was found that the estimated trajectory projection errors from the RUC-2 using 1-2-h forecasts averaged 9 s for ascent/descent flight segments of approximately 15 min, and about 10 s for en route segments of the same duration. C1 NOAA, ERL, Forecast Syst Lab, Boulder, CO 80301 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Schwartz, BE (reprint author), NOAA, ERL, Forecast Syst Lab, 325 Broadway, Boulder, CO 80301 USA. RI Benjamin, Stan/C-5818-2015 OI Benjamin, Stan/0000-0002-5751-8236 NR 23 TC 15 Z9 15 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 JUN PY 2000 VL 15 IS 3 BP 313 EP 326 DI 10.1175/1520-0434(2000)015<0313:AORARW>2.0.CO;2 PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 323AZ UT WOS:000087543800004 ER PT J AU Su, TJ Green, RJ Wang, Y Murphy, EF Lu, JR Ivkov, R Satija, SK AF Su, TJ Green, RJ Wang, Y Murphy, EF Lu, JR Ivkov, R Satija, SK TI Adsorption of lysozyme onto the silicon oxide surface chemically grafted with a monolayer of pentadecyl-1-ol SO LANGMUIR LA English DT Article ID SELF-ASSEMBLED MONOLAYERS; BOVINE SERUM-ALBUMIN; WATER-INTERFACE; NEUTRON REFLECTION; PROTEIN ADSORPTION; ELLIPSOMETRY; PH AB The adsorption of chicken egg white lysozyme at the functionalized silicon oxide-solution interface has been studied using the combined measurement of spectroscopic ellipsometry and neutron reflection. The solid oxide surface was modified by coating a self-assembled monolayer of pentadecyltrichlorosilane with terminal hydroxyl groups (abbreviated to C15OH) Neutron reflection measurement at the solid-D2O interface showed that the C15OH layer was 16 +/- 2 PI thick and the volume fraction was 0.94 +/- 0.05, suggesting the formation of a close-packed monolayer. The adsorption of lysozyme was made at pH 4 and 7 with lysozyme concentration ranging from 0.03 to 4 g dm(-3). The results were then compared with those from previous studies at the hydrophilic SiO2-water and the hydrophobed SiO2-water interfaces, with the latter formed by coating a monolayer of octadecyl trichlorosilane (abbreviated to OTS). At 0.03 g dm(-3) and pH 7 the surface excess was found to be 0.6 +/- 0.3 mg m(-2) at the C15OH-water interface, as,compared with 1.7 mg m(-2) at the SiO2-water interface and 1.9 mg m(-2) at the OTS-water interface. As lysozyme concentration is increased to 4 g dm(-3), the surface excess at the C15OH-water interface reaches 2.1 mg m(-2), as compared with 4.7 mg m(-2) at the hydrophilic SiO2-water interface and 5.1 mg m(-2) at the OTS-water interface. These values demonstrate the attainment of the minimum surface excess on the hydroxyl surface. Shifting solution pH from 7 to 4 reduces adsorption on all the surfaces studied, but the lowest level of adsorption is again obtained on the hydroxyl surface. The reversibility of the adsorption at the C15OH-water interface was examined by cycling the solution pH at different lysozyme concentrations. Adsorption was found to be completely reversible at the low lysozyme concentration of 1 g dm(-3), while at the high concentration of 4 g dm(-3) the adsorption was irreversible. C1 Univ Surrey, Dept Chem, Guildford GU2 5XH, Surrey, England. NIST, Ctr Neutron Res, Gaithersburg, MD 20899 USA. RP Lu, JR (reprint author), Univ Surrey, Dept Chem, Guildford GU2 5XH, Surrey, England. RI Ivkov, Robert/A-3902-2015; OI Ivkov, Robert/0000-0002-2930-5276; Green, Rebecca/0000-0001-6783-549X NR 30 TC 36 Z9 38 U1 1 U2 4 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0743-7463 J9 LANGMUIR JI Langmuir PD MAY 30 PY 2000 VL 16 IS 11 BP 4999 EP 5007 DI 10.1021/la991559j PG 9 WC Chemistry, Multidisciplinary; Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA 318VG UT WOS:000087304100037 ER PT J AU Nisato, G Ivkov, R Amis, EJ AF Nisato, G Ivkov, R Amis, EJ TI Size invariance of polyelectrolyte dendrimers SO MACROMOLECULES LA English DT Article ID ANGLE NEUTRON-SCATTERING; INDIRECT TRANSFORMATION METHOD; MOLECULES AB To quantify the swelling response of polyelectrolyte dendrimers in aqueous solutions as affected by changes in solution conditions, we have studied eighth generation, G8, poly(amidoamine) (PAMAM) dendrimers in D2O using small-angle neutron scattering. The charge density is manipulated by varying the pH of the solution in order to protonate and deprotonate the primary and tertiary amines. The coherent scattered intensity at high q values yields size information from the form factor of individual dendrimers. The distance distribution functions of the dendrimers in a variety of experimental situations were determined by indirect Fourier transform. For all the conditions studied, we find that the size of G8 dendrimers is essentially insensitive to variations of the pH (4.7 < pH < 10.1) and of ionic strength (up to 3 M of NaCl). In all cases, the scattering curves yield density profiles that correspond well to a uniform sphere with a radius of gyration R-G = 4.0 +/- 0.15 nm. We conclude that the dendrimer size is essentially independent of the charge density or ionic strength of the solvent, contrary to the predictions of current models and simulations. 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 8540, Gaithersburg, MD 20899 USA. RI Ivkov, Robert/A-3902-2015 OI Ivkov, Robert/0000-0002-2930-5276 NR 22 TC 96 Z9 97 U1 1 U2 18 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0024-9297 J9 MACROMOLECULES JI Macromolecules PD MAY 30 PY 2000 VL 33 IS 11 BP 4172 EP 4176 DI 10.1021/ma991474p PG 5 WC Polymer Science SC Polymer Science GA 320AF UT WOS:000087378300034 ER PT J AU Barnes, KA Karim, A Douglas, JF Nakatani, AI Gruell, H Amis, EJ AF Barnes, KA Karim, A Douglas, JF Nakatani, AI Gruell, H Amis, EJ TI Suppression of dewetting in nanoparticle-filled polymer films SO MACROMOLECULES LA English DT Article ID CONTACT-ANGLE HYSTERESIS; LIQUID-FILMS; THIN; DYNAMICS; SURFACES; RUPTURE; DEFECTS AB The perturbing influence of nanosize filler particles on the dewetting of spun-cast polymer films is investigated. Previous studies have shown that spun-cast films of unentangled polystyrene (PS) and polybutadiene (PB) dewet acid-cleaned silicon wafers when the films are annealed above their bulk glass transition temperature T-g. It is also known that "impurity" particles tend to promote dewetting in thin polymer films. Here we demonstrate that the addition of a small amount of C-60 fullerene nanoparticles to the spin-casting polymer solution leads to an inhibition of dewetting in thin (L < 100 nm) PS and PB films cast on both acid-cleaned and carbon-coated silicon wafer substrates. Neutron reflection measurements indicate that this effect is associated with the formation of a diffuse fullerene layer near the solid substrate. Evidently, the immobilized fullerene particles form an enrichment layer at the solid boundary and "pin" the contact line of the growing dewetted ("dry") regions so that hole growth in the filled films becomes arrested at a scale which diminishes with increasing filler concentration. Above a relative filler-polymer mass fraction of 1%, we no longer observe hole formation by atomic force microscopy on the time scales of our measurements (typically on the order of hours), suggesting the existence of a critical filler surface coverage for the suppression of dewetting. The roughness of the fullerene layer probably also contributes to the modification of the surface wetting properties through a change in the surface energy of the substrate, as suggested by recent measurements on substrates "roughened" by other means such as irradiation of polymer film substrates, grafting of polymer chains, etc. C1 NIST, Div Polymers, Gaithersburg, MD 20899 USA. RP NIST, Div Polymers, Gaithersburg, MD 20899 USA. NR 33 TC 135 Z9 135 U1 2 U2 61 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0024-9297 EI 1520-5835 J9 MACROMOLECULES JI Macromolecules PD MAY 30 PY 2000 VL 33 IS 11 BP 4177 EP 4185 DI 10.1021/ma990614s PG 9 WC Polymer Science SC Polymer Science GA 320AF UT WOS:000087378300035 ER PT J AU Diddams, SA Jones, DJ Ye, J Cundiff, ST Hall, JL Ranka, JK Windeler, RS Holzwarth, R Udem, T Hansch, TW AF Diddams, SA Jones, DJ Ye, J Cundiff, ST Hall, JL Ranka, JK Windeler, RS Holzwarth, R Udem, T Hansch, TW TI Direct link between microwave and optical frequencies with a 300 THz femtosecond laser comb SO PHYSICAL REVIEW LETTERS LA English DT Article ID MODE-LOCKED LASER; TRANSITION; REALIZATION AB We demonstrate a great simplification in the long-standing problem of measuring optical frequencies in terms of the cesium primary standard. An air-silica microstructure optical fiber broadens the frequency comb of a femtosecond laser to span the optical octave from 1064 to 532 nm, enabling us to measure the 282 THz frequency of an iodine-stabilized Nd:YAG laser directly in terms of the microwave frequency that controls the comb spacing. Additional measurements of established optical frequencies at 633 and 778 nm using the same femtosecond comb confirm the accepted uncertainties for these standards. C1 Natl Inst Stand & Technol, Div Time & Frequency, Boulder, CO 80303 USA. Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. Bell Labs, Lucent Technol, Murray Hill, NJ 07974 USA. Max Planck Inst Quantum Opt, D-85748 Garching, Germany. RP Diddams, SA (reprint author), Natl Inst Stand & Technol, Div Time & Frequency, 325 Broadway, Boulder, CO 80303 USA. EM jhall@jila.colorado.edu RI Cundiff, Steven/B-4974-2009; Ye, Jun/C-3312-2011; Diddams, Scott/L-2819-2013; Jones, David/F-5859-2017 OI Cundiff, Steven/0000-0002-7119-5197; NR 16 TC 723 Z9 742 U1 19 U2 131 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 MAY 29 PY 2000 VL 84 IS 22 BP 5102 EP 5105 DI 10.1103/PhysRevLett.84.5102 PG 4 WC Physics, Multidisciplinary SC Physics GA 318CL UT WOS:000087266300018 ER PT J AU Covington, M Keller, MW Kautz, RL Martinis, JM AF Covington, M Keller, MW Kautz, RL Martinis, JM TI Photon-assisted tunneling in electron pumps SO PHYSICAL REVIEW LETTERS LA English DT Article ID NOISE; ACCURACY; JUNCTIONS; TRANSPORT; BEHAVIOR; DEVICES; ERRORS AB We measure photon-assisted tunneling in 4- and 6-junction electron pumps at photon frequencies up to 60 GHz. We determine the microwave voltage at the pumps using noise thermometry. The standard theory of leakage in the electron pump, modified to include photon-assisted tunneling, describes our experiments well. From this test of theory we argue that, in the absence of external microwaves, photon-assisted tunneling driven by 1/f noise is an important error mechanism in electron pumps. C1 Natl Inst Stand & Technol, Boulder, CO 80303 USA. RP Covington, M (reprint author), Natl Inst Stand & Technol, 325 Broadway, Boulder, CO 80303 USA. NR 24 TC 43 Z9 45 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 MAY 29 PY 2000 VL 84 IS 22 BP 5192 EP 5195 DI 10.1103/PhysRevLett.84.5192 PG 4 WC Physics, Multidisciplinary SC Physics GA 318CL UT WOS:000087266300041 ER PT J AU Gehring, PM Park, SE Shirane, G AF Gehring, PM Park, SE Shirane, G TI Soft phonon anomalies in the relaxer ferroelectric Pb(Zn1/3Nb2/3)(0.92)Ti0.08O3 SO PHYSICAL REVIEW LETTERS LA English DT Article ID X-RAY-SCATTERING; PHASE-TRANSITIONS; SINGLE-CRYSTALS; PEROVSKITE ALLOYS; LEAD MAGNONIOBATE; PBMG1/3NB2/3O3; BEHAVIOR AB Neutron inelastic scattering measurements of the polar transverse optic phonon mode dispersion in the cubic relaxor Pb(Zn1/3Nb2/3)(0.92)Ti0.08O3 at 500 K reveal anomalous behavior in which the optic branch appears to drop precipitously into the acoustic branch at a finite value of the momentum transfer q = 0.2 Angstrom(-1) measured from the zone center. We speculate that this behavior is the result of nanometer-sized polar regions in the crystal. C1 Natl Inst Stand & Technol, Ctr Neutron Res, Gaithersburg, MD 20899 USA. Penn State Univ, Mat Res Lab, University Pk, PA 16802 USA. Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. RP Gehring, PM (reprint author), Natl Inst Stand & Technol, Ctr Neutron Res, Gaithersburg, MD 20899 USA. OI Gehring, Peter/0000-0002-9236-2046 NR 20 TC 120 Z9 121 U1 0 U2 15 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 MAY 29 PY 2000 VL 84 IS 22 BP 5216 EP 5219 DI 10.1103/PhysRevLett.84.5216 PG 4 WC Physics, Multidisciplinary SC Physics GA 318CL UT WOS:000087266300047 ER PT J AU Geltman, S AF Geltman, S TI Ionization of H(1s) by laser pulses: a close-coupling study SO JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS LA English DT Article ID ATOMIC-HYDROGEN; MULTIPHOTON AB Here we present one of the first complete treatments of the ionization of a real atom by realistic laser pulses of arbitrary length and intensity. A large basis set of hydrogenic bound and discretized continuum states is employed in a close-coupling solution of the full time-dependent Schrodinger equation to give converged results for the resulting ionization probability for H(1s). Various laser frequencies, corresponding to one- and three-photon ionization and the 1s-2p resonance, as well as laser intensities in the multi-photon, tunnelling and over-the-barrier ionization regimes are examined. It is seen that the ionization probability of H(1s) following a laser Dulse is a very complicated function of frequency, phase, pulse shape, pulse length and intensity. C1 Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. Natl Inst Stand & Technol, Boulder, CO 80309 USA. RP Geltman, S (reprint author), Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. NR 15 TC 22 Z9 23 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 MAY 28 PY 2000 VL 33 IS 10 BP 1967 EP 1979 DI 10.1088/0953-4075/33/10/310 PG 13 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 327HP UT WOS:000087788700011 ER PT J AU Kim, YK Rudd, ME AF Kim, YK Rudd, ME TI Comments on 'Electron impact ionization of methane' SO JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS LA English DT Article ID CHARGED PARTICLES; CROSS-SECTIONS; MOLECULES; ATOMS AB It has been claimed by Khare et al (1999 J. Phys. B: At. Mol. Opt. Phys. 32 3147) that the binary-encounter dipole (BED) model and its simpler version, binary-encounter Bethe (BEB) model, for electron-impact ionization of atoms and molecules published earlier by the present authors (1994 Phys. Rev A 50 3954) (a) are approximations to their theory, (b) contained an error in the derivation of one of our basic formulae and (c) contained a value of a parameter associated with the Born approximation that differed from the known value by almost two orders of magnitude. we show that these claims and some other statements by Khare et al are incorrect and originate from a misunderstanding of the approximations we have made. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Univ Nebraska, Dept Phys & Astron, Lincoln, NE 68588 USA. RP Kim, YK (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NR 7 TC 6 Z9 6 U1 2 U2 3 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0953-4075 J9 J PHYS B-AT MOL OPT JI J. Phys. B-At. Mol. Opt. Phys. PD MAY 28 PY 2000 VL 33 IS 10 BP 1981 EP 1984 DI 10.1088/0953-4075/33/10/401 PG 4 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 327HP UT WOS:000087788700012 ER PT J AU Holloway, T Levy, H Kasibhatla, P AF Holloway, T Levy, H Kasibhatla, P TI Global distribution of carbon monoxide SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID CHEMICAL-TRANSPORT MODEL; GENERAL-CIRCULATION MODEL; ATMOSPHERIC METHANE; TROPOSPHERIC OZONE; DRY SEASON; CHEMISTRY; EMISSIONS; CO; OH; SIMULATION AB This study explores the evolution and distribution of carbon monoxide (CO) using the National Oceanic and Atmospheric Administration (NOAA) Geophysical Fluid Dynamics Laboratory three-dimensional global chemical transport model (GFDL GCTM). The work aims to gain an improved understanding of the global carbon monoxide budget, specifically focusing on the contribution of each of the four source terms to the seasonal variability of CO. The sum of all CO sources in the model is 2.5 Pg CO/yr (1 Pg = 10(3) Tg) including fossil fuel use (300 Tg CO /yr), biomass burning (748 Tg CO/yr), oxidation of biogenic hydrocarbons (683 Tg CO/yr), and methane oxidation (760 Tg CO/yr). The main sink for CO is destruction by the hydroxyl radical, and we assume a hydroxyl distribution based on three-dimensional monthly varying fields given by Spivakovsky et al. [1990], but we increase this field by 15% uniformly to agree with a methyl chloroform lifetime of 4.8 years [Prinn et al., 1995]. Our simulation produces a carbon monoxide field that agrees well with available measurements from the NOAA/Climate Monitoring and Diagnostics Laboratory global cooperative flask sampling network and from the Jungfraujoch observing station of the Swiss Federal Laboratories for Materials Testing and Research (EMPA) (93% of seasonal-average data points agree within +/-25%) and flight data from measurement campaigns of the NASA Global Tropospheric Experiment (79% of regional-average data points agree within +/-25%). For all 34 ground-based measurement sites we have calculated the percentage contribution of each CO source term to the total model-simulated distribution and examined how these contributions vary seasonally due to transport, changes in OH concentration, and seasonality of emission sources. CO from all four sources contributes to the total magnitude of CO in all regions. Seasonality, however, is usually governed by the transport and destruction by OH of CO emitted by fossil fuel and/or biomass burning. The sensitivity to the hydroxyl field varies spatially, with a 30% increase in OH yielding decreases in CO ranging from 4-23%, with lower sensitivities near emission regions where advection acts as a strong local sink. The lifetime of CO varies from 10 days over summer continental regions to well over a year at the winter poles, where we define lifetime as the turnover time in the troposphere due to reaction with OH. C1 Princeton Univ, Atmospher & Ocean Sci Program, Princeton, NJ 08544 USA. Geophys Fluid Dynam Lab, Princeton, NJ 08542 USA. Duke Univ, Nicholas Sch Environm, Durham, NC 27708 USA. RP Princeton Univ, Atmospher & Ocean Sci Program, Princeton, NJ 08544 USA. EM tah@gfdl.gov; hl@gfdl.gov RI Kasibhatla, Prasad/A-2574-2010; OI Kasibhatla, Prasad/0000-0003-3562-3737 NR 62 TC 152 Z9 161 U1 8 U2 38 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 MAY 27 PY 2000 VL 105 IS D10 BP 12123 EP 12147 DI 10.1029/1999JD901173 PG 25 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 319WL UT WOS:000087366600003 ER PT J AU Reid, SJ Tuck, AF Kiladis, G AF Reid, SJ Tuck, AF Kiladis, G TI On the changing abundance of ozone minima at northern midlatitudes SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID LOWER STRATOSPHERE; TROPOSPHERE; CIRCULATION; TRANSPORT; DEPLETION; AIR; ADVECTION; MONSOON; WINTER; MODEL AB An analysis of ozonesonde data for stations whose records go back at least a quarter of a century suggests that the number of intrusions of subtropical air into the midlatitude lower stratosphere has recently increased. These air masses, refer-red to here as ozone minima, contain low ozone concentrations over vertical depths of similar to 4 km, sufficient to reduce the total ozone column by 10-15%. The mixing ratios of other trace species, such as nitrous oxide (N2O), carbon monoxide (CO), and water vapor (H2O) recorded in midlatitudes by the NASA ER-2 aircraft, suggest that these intrusions originate either in the lower tropical stratosphere or in the upper tropical troposphere. Potential vorticity calculated from the European Centre for Medium-Range Weather Forecasts (ECMWF) and National Center for Environmental Prediction (NCEP) date, have been used in conjunction with TOMS total ozone data to estimate the typical area covered by minima. Their contribution to the midlatitude ozone trend is discussed. TOVS data have also facilitated the identification of a prominent ozone minima source region in the subtropical western Atlantic, where the Atlantic storm track is particularly intense. Minima frequently advect over Europe, explaining the high abundance of these events observed by European ozonesonde stations, relative to ozonesonde data from Canada. C1 NOAA, Cooperat Inst Res Environm Sci, Boulder, CO 80303 USA. NOAA, Aeron Lab, Boulder, CO 80303 USA. RP NOAA, Cooperat Inst Res Environm Sci, Boulder, CO 80303 USA. EM sreid@al.noaa.gov RI Tuck, Adrian/F-6024-2011 OI Tuck, Adrian/0000-0002-2074-0538 NR 40 TC 46 Z9 46 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 MAY 27 PY 2000 VL 105 IS D10 BP 12169 EP 12180 DI 10.1029/2000JD900081 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 319WL UT WOS:000087366600006 ER PT J AU Beesley, JA Bretherton, CS Jakob, C Andreas, EL Intrieri, JM Uttal, TA AF Beesley, JA Bretherton, CS Jakob, C Andreas, EL Intrieri, JM Uttal, TA TI A comparison of cloud and boundary layer variables in the ECMWF forecast model with observations at Surface Heat Budget of the Arctic Ocean (SHEBA) ice camp SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID RADAR REFLECTIVITY; CLIMATE MODEL; SIMULATIONS; RADIATION AB Cloud and boundary layer variables from the European Centre for Medium-Range Weather Forecasts (ECMWF) forecast model were compared with measurements made from surface instruments and from upward looking 8 mm wavelength radar and lidar at the Surface Heat Budget of the Arctic Ocean (SHEBA) ice camp during November and December of 1997. The precipitation accumulation, near-surface winds, and surface downward longwave irradiance predicted by the model were in good agreement with SHEBA observations during this period. However, surface downward longwave irradiance was underestimated by 10 W m(-2) on average when low clouds were present in the model and observations. The model demonstrated considerable skill in predicting the occurrence and vertical extent of cloudiness over SHEBA, with some tendency to overestimate the frequency of clouds below 1 km. A synthetic radar reflectivity estimated from the ECMWF model variables was compared with 8 mm wavelength radar measurements. The two were broadly consistent only if the assumed snowflake size distribution over SHEBA had a smaller proportion of large flakes than was found in previous studies at lower latitudes. The ECMWF model assumes a temperature-dependent partitioning of cloud condensate between water and ice. Lidar depolarization measurements at SHEBA indicate that both liquid and ice phase clouds occurred over a wide range of temperatures throughout the winter season, with liquid occurring at temperatures as low as 239 K. A much larger fraction of liquid water clouds was observed than the ECMWF model predicted. The largest discrepancies between the ECMWF model and the observations were in surface temperature (up to 15 K) and turbulent sensible heat fluxes (up to 60 W m(-2)). These appear to be due at least partially to the ECMWF sea ice model, which did not allow surface temperatures to respond nearly as rapidly to changing atmospheric conditions as was observed. C1 Univ Illinois, Dept Atmospher Sci, Urbana, IL 61801 USA. Natl Ice Ctr, Washington, DC USA. European Ctr Medium Range Weather Forecasts, Reading RG2 9AX, Berks, England. USA, Cold Reg Res & Engn Lab, Hanover, NH 03755 USA. NOAA, Environm Res Lab, Boulder, CO 80303 USA. RP Univ Illinois, Dept Atmospher Sci, 105 S Gregory Ave, Urbana, IL 61801 USA. EM tonyb@atmos.uiuc.edu; breth@atmos.washington.edu; eandreas@ccrel.usace.army.mil; tuttal@etl.noaa.gov RI Intrieri, Janet/D-5608-2015; Jakob, Christian/A-1082-2010 OI Jakob, Christian/0000-0002-5012-3207 NR 20 TC 52 Z9 52 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 MAY 27 PY 2000 VL 105 IS D10 BP 12337 EP 12349 DI 10.1029/2000JD900079 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 319WL UT WOS:000087366600021 ER PT J AU Gonzalez, C Lim, EC AF Gonzalez, C Lim, EC TI Electronic spectra and photophysics of the two stable conformers of anthracene dimer: evaluation of an ab initio structure prediction SO CHEMICAL PHYSICS LETTERS LA English DT Article ID NAPHTHALENE CLUSTERS; HYDROCARBONS; SPECTROSCOPY; TRIMER; FIELD; MM3; JET AB It is shown that the spectral features and excited-state dynamics of the two Van der Waals dimers of anthracene, generated by supersonic free expansion, can be accounted for if the dimers have the crossed (D-2d) and the parallel-displaced (C-2h) structures predicted by an ab initio calculation with MP2 correlation. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Univ Akron, Dept Chem, Akron, OH 44325 USA. Natl Inst Stand & Technol, Phys & Chem Properties Div, Gaithersburg, MD 20899 USA. RP Lim, EC (reprint author), Univ Akron, Dept Chem, Akron, OH 44325 USA. NR 16 TC 30 Z9 30 U1 0 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0009-2614 J9 CHEM PHYS LETT JI Chem. Phys. Lett. PD MAY 26 PY 2000 VL 322 IS 5 BP 382 EP 388 DI 10.1016/S0009-2614(00)00451-6 PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 318EZ UT WOS:000087272100013 ER PT J AU Nauta, K Miller, RE Fraser, GT Lafferty, WJ AF Nauta, K Miller, RE Fraser, GT Lafferty, WJ TI The infrared spectrum and internal rotation barrier in HF-BF3 SO CHEMICAL PHYSICS LETTERS LA English DT Article ID FRIEDEL-CRAFTS CATALYSTS; ELECTRONIC-STRUCTURE; AB-INITIO; MICROWAVE; SPECTROSCOPY; HCN-BF3; DIMER; BF3 AB The rotationally resolved infrared spectrum of the HF stretch fundamental in combination with one quantum of internal rotation excitation has been investigated for the HF-BF3 complex using a color-center-laser optothermal molecular-beam spectrometer. The infrared band origin is red-shifted by 3.9 cm(-1) from the HF monomer origin. The magnitude of the Coriolis interaction in the m = +/-1 internal rotor state observed in combination with the HF stretch gives a barrier to internal rotation of 54 cm(-1) in the HF stretch excited state. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Natl Inst Stand & Technol, Opt Technol Div, Gaithersburg, MD 20899 USA. Univ N Carolina, Dept Chem, Chapel Hill, NC 27599 USA. RP Fraser, GT (reprint author), Natl Inst Stand & Technol, Opt Technol Div, Gaithersburg, MD 20899 USA. NR 20 TC 5 Z9 5 U1 2 U2 3 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 MAY 26 PY 2000 VL 322 IS 5 BP 401 EP 406 DI 10.1016/S0009-2614(00)00416-4 PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 318EZ UT WOS:000087272100016 ER PT J AU Olson, DH Khosrovani, N Peters, AW Toby, BH AF Olson, DH Khosrovani, N Peters, AW Toby, BH TI Crystal structure of dehydrated CsZSM-5 (5.8A1): Evidence for nonrandom aluminum distribution SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID CATION LOCATION; ZEOLITE ZSM-5; QUANTUM AB The crystal structure of dehydrated CS5.8Al5.8Si90.2O192 has been determined by Rietveld refinement of synchrotron powder diffraction data. The structure was refined in the Pnma space group to R-wp = 2.52% and R(F-2) = 5.32%. Cs ions were found with partial occupancy in three different positions. One Of these, Cs1, is in the channel intersection, near the sinusoidal channel 10-ring system and adjacent to a four-membered ring. The second, Cs2, is in the straight channel 10-ring. The third, Cs3, is 3.18 Angstrom from the Cs1 and also in the sinusoidal channel 10-ring area. The total Cs occupancy is 5.32(3) Cs ions, which compares well with the Cs unit cell content of 5.8 calculated from the chemical analysis. Modeling of the effect of aluminum siting on the position of Cs+ ions in the zeolite channel indicates that the Cs' ion has its closest interaction with an oxygen atom attached to the aluminum atom Tor Al substitution at each of the 12 ZSM-5 T-sites. From this result we conclude that Csi ion positioning provides information on aluminum atom distribution. The T sites 4. 7, 10, 11, and 12 have Cs-O distances less than similar to 3.55 Angstrom, indicating that they are possible sites for Al atoms. The oxygen atoms attached to T sites 2, 8, and 9 have no Cs-O distances shorter than 3.90 Angstrom, suggesting that there is a low probability that these sites contain Al atoms. C1 Univ Penn, Dept Chem Engn, Philadelphia, PA 19104 USA. Mol Simulat Inc, San Diego, CA 92121 USA. Grace Div, Columbia, MD 21044 USA. NIST, Ctr Neutron Res, Gaithersburg, MD 20899 USA. RP Olson, DH (reprint author), Univ Penn, Dept Chem Engn, 311A Towne Bldg,220 S 33rd St, Philadelphia, PA 19104 USA. RI Toby, Brian/F-3176-2013 OI Toby, Brian/0000-0001-8793-8285 NR 14 TC 88 Z9 88 U1 0 U2 22 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 MAY 25 PY 2000 VL 104 IS 20 BP 4844 EP 4848 DI 10.1021/jp000417r PG 5 WC Chemistry, Physical SC Chemistry GA 317GW UT WOS:000087218500005 ER PT J AU Work, TM Balazs, GH Rameyer, RA Chang, SP Berestecky, J AF Work, TM Balazs, GH Rameyer, RA Chang, SP Berestecky, J TI Assessing humoral and cell-mediated immune response in Hawaiian green turtles, Chelonia mydas SO VETERINARY IMMUNOLOGY AND IMMUNOPATHOLOGY LA English DT Article DE green turtle; Chelonia mydas; enzyme linked immunosorbent assay; Freund's adjuvant; Gerbu; ISA-70; lymphocyte stimulation test ID MARINE TURTLES; BLOOD; FIBROPAPILLOMATOSIS; ANTIBODIES; PHYLOGENY; ISLANDS; SERUM AB Seven immature green turtles, Chelonia mydas, captured from Kaneohe Bay on the island of Oahu were used to evaluate methods for assessing their immune response. Two turtles each were immunized intramuscularly with egg white lysozyme (EWL) in Freund's complete adjuvant, Gerbu, or ISA-70; a seventh turtle was immunized with saline only and served as a control. Humoral immune response was measured with an indirect enzyme linked immunosorbent assay (ELISA). Cell-mediated immune response was measured using in vitro cell proliferation assays (CPA) using whole blood or peripheral blood mononuclear cells (PBM) cultured with concanavalin A (ConA), phytohaemagglutinin (PHA), or soluble egg EWL antigen. All turtles, except for one immunized with Gerbu and the control, produced a detectable humoral immune response by 6 weeks which persisted for at least 14 weeks after a single immunization. All turtles produced an anamnestic humoral immune response after secondary immunization. Antigen specific cell-mediated immune response in PBM was seen in all turtles either after primary or secondary immunization, but it was not as consistent as humoral immune response; antigen specific cell-mediated immune response in whole blood was rarely seen. Mononuclear cells had significantly higher stimulation indices than whole blood regardless of adjuvant, however, results with whole blood had lower variability. Both Gerbu and ISA-70 appeared to potentiate the cell-mediated immune response when PBM or whole blood were cultured with PHA. This is the first time cell proliferation assays have been compared between whole blood and PBM for reptiles. This is also the first demonstration of antigen specific cell-mediated response in reptiles. Cell proliferation assays allowed us to evaluate the cell-mediated immune response of green turtles. However, CPA may be less reliable than ELISA for detecting antigen specific immune response. Either of the three adjuvants appears suitable to safely elicit a detectable immune response in green turtles. (C) 2000 Elsevier Science B.V. All rights reserved. C1 US Geol Survey, Biol Resources Div, Natl Wildlife Hlth Ctr, Honolulu Field Stn, Honolulu, HI 96850 USA. NOAA, Natl Marine Fisheries Serv, SW Fisheries Sci Ctr, Honolulu Lab, Honolulu, HI 96822 USA. Univ Hawaii, Dept Trop Med, Honolulu, HI 96816 USA. Univ Hawaii, Kapiolani Community Coll, Dept Microbiol, Honolulu, HI 96816 USA. RP Work, TM (reprint author), US Geol Survey, Biol Resources Div, Natl Wildlife Hlth Ctr, Honolulu Field Stn, POB 50167, Honolulu, HI 96850 USA. RI Work, Thierry/F-1550-2015 OI Work, Thierry/0000-0002-4426-9090 NR 40 TC 26 Z9 26 U1 1 U2 7 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0165-2427 J9 VET IMMUNOL IMMUNOP JI Vet. Immunol. Immunopathol. PD MAY 23 PY 2000 VL 74 IS 3-4 BP 179 EP 194 DI 10.1016/S0165-2427(00)00168-9 PG 16 WC Immunology; Veterinary Sciences SC Immunology; Veterinary Sciences GA 315EZ UT WOS:000087100800002 PM 10802287 ER PT J AU Ilavsky, J Stalick, JK AF Ilavsky, J Stalick, JK TI Phase composition and its changes during annealing of plasma-sprayed YSZ SO SURFACE & COATINGS TECHNOLOGY LA English DT Article DE phase transitions; X-ray diffraction; sintering; zirconium oxide; yttrium oxide; neutron scattering ID ZIRCONIA; GROWTH AB The phase composition of plasma-sprayed yttria stabilized zirconia (YSZ), ZrO2 with 8% by mass Y2O3, was studied using neutron and X-ray diffraction. Comparison shows that neutron diffraction is superior for analysis of the phase composition as well as for the analysis of the yttria content of the tetragonal phase. The presence of large amounts of the cubic phase is probably often neglected or underestimated in standard XRD analysis due to scattering-related limitations and the inherent difficulty of the analysis. The importance of this fact needs to be addressed in future studies. The amount of monoclinic, tetragonal, and cubic phases was determined using neutron Rietveld refinement for feedstock powders, as-sprayed deposits and for samples annealed for 1 h at temperatures of 1100, 1200, 1300, and 1400 degrees C. The two studied feedstock materials were manufactured by different production methods, and contained various amounts of the monoclinic phase depending on manufacturing method. While the tetragonal phase dominated, both feedstock powders also contained significant amounts of the cubic phase. The as-sprayed deposits were composed of mostly tetragonal phase, with only traces of the monoclinic phase; the amount of the cubic phase was reduced with respect to the feedstock. For one of the materials the cubic phase content remained significant (approx. 25% by mass), and for the other the cubic phase content was significantly lower (approx. 6% by mass). The cubic phase content after annealing at 1400 degrees C was in both cases similar - approximately 40% by mass. There was no significant change in monoclinic phase content observed in this experiment. The yttria fraction within the tetragonal and cubic phases was followed and changes are discussed. (C) 2000 Elsevier Science S.A. All rights reserved. C1 NIST, Ctr Neutron Res, Gaithersburg, MD 20899 USA. Univ Maryland, College Pk, MD 20742 USA. RP Ilavsky, J (reprint author), NIST, Ctr Neutron Res, Gaithersburg, MD 20899 USA. RI Ilavsky, Jan/D-4521-2013 OI Ilavsky, Jan/0000-0003-1982-8900 NR 17 TC 69 Z9 69 U1 2 U2 21 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0257-8972 J9 SURF COAT TECH JI Surf. Coat. Technol. PD MAY 22 PY 2000 VL 127 IS 2-3 BP 120 EP 129 DI 10.1016/S0257-8972(00)00562-4 PG 10 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA 325EF UT WOS:000087662800003 ER PT J AU Belmonte, A Rye, BJ AF Belmonte, A Rye, BJ TI Heterodyne lidar returns in the turbulent atmosphere: performance evaluation of simulated systems SO APPLIED OPTICS LA English DT Article ID 3-DIMENSIONAL RANDOM-MEDIA; COHERENT LASER-RADAR; REFRACTIVE-TURBULENCE; WAVE-PROPAGATION; TARGET AB Simulations of beam propagation in three-dimensional random media were used to study the effects of atmospheric refractive turbulence on coherent lidar performance. By use of the two-beam model, the lidar return is expressed in terms of the overlap integral of the transmitter and the virtual (back-propagated) local oscillator beams at the target, reducing the problem to one of computing irradiance along the two propagation paths. This approach provides the tools for analyzing laser radar with general reactive turbulence conditions beam truncation at the antenna aperture, beam-angle misalignment, and arbitrary transmitter and receiver configurations. Simplifying assumptions used in analytical studies, were tested and treated as benchmarks for determining the accuracy of the simulations. The simulation permitted characterization of the effect on lidar performance of the analytically intractable return variance that results from turbulent fluctuations as well as of the heterodyne optical power and system-antenna efficiency. (C) 2000 Optical Society of America OCIS codes: 030.1670, 010.3640, 010.1300, 010.1330. C1 NOAA, Environm Technol Lab, Boulder, CO 80303 USA. Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. RP Belmonte, A (reprint author), NOAA, Environm Technol Lab, R-E-ET2,325 Broadway, Boulder, CO 80303 USA. EM abelmonte@etl.noaa.gov NR 27 TC 25 Z9 28 U1 2 U2 9 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1559-128X EI 2155-3165 J9 APPL OPTICS JI Appl. Optics PD MAY 20 PY 2000 VL 39 IS 15 BP 2401 EP 2411 DI 10.1364/AO.39.002401 PG 11 WC Optics SC Optics GA 315NQ UT WOS:000087120200004 PM 18345150 ER PT J AU Heinz, S Begelman, MC AF Heinz, S Begelman, MC TI Jet acceleration by tangled magnetic fields SO ASTROPHYSICAL JOURNAL LA English DT Article DE acceleration of particles; galaxies : jets; MHD ID GAMMA-RAY BURSTS; M87 JET; RELATIVISTIC PLASMA; ACCRETION DISKS; RADIO-SOURCES; BLACK-HOLES; MODEL AB We explore the possibility that extragalactic radio jets might be accelerated by highly disorganized magnetic fields that are strong enough to dominate the dynamics until the terminal Lorentz factor is reached. Following the twin-exhaust model by Blandford & Rees, the collimation under this scenario is provided by the stratified thermal pressure from an external medium. The acceleration efficiency then depends on the pressure gradient of that medium. In order for this mechanism to work there must be continuous tangling of the magnetic field, changing the magnetic equation of state away from pure flux freezing (otherwise, conversion of Poynting flux to kinetic energy flux is suppressed). This is a complementary approach to models in which the plasma is accelerated by large-scale ordered fields. We include a simple prescription for magnetic dissipation, which leads to trade-offs among conversion of magnetic energy into bulk kinetic energy, random particle energy, and radiation. We present analytic dynamical solutions of such jets, assess the effects of radiation drag, and comment on observational issues, such as the predicted polarization and synchrotron brightness. Finally, we try to make the connection to observed radio galaxies and gamma-ray bursts. C1 Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. Natl Inst Stand & Technol, Boulder, CO 80309 USA. Univ Calif Santa Barbara, Inst Theoret Phys, Santa Barbara, CA 93106 USA. Univ Colorado, Dept Astrophys & Planetary Sci, Boulder, CO 80309 USA. RP Heinz, S (reprint author), Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. NR 23 TC 43 Z9 43 U1 0 U2 0 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 MAY 20 PY 2000 VL 535 IS 1 BP 104 EP 117 DI 10.1086/308820 PN 1 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 325DW UT WOS:000087661900010 ER PT J AU Grodkowski, J Neta, P AF Grodkowski, J Neta, P TI Ferrous ions as catalysts for photochemical reduction of CO2 in homogeneous solutions SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID TERPHENYL-SENSITIZED PHOTOREDUCTION; TRANSITION-METAL COMPLEXES; CARBON-DIOXIDE; AQUEOUS-SOLUTION; IRON; RADIATION; COBALT; NI(CYCLAM)(+); RADIOLYSIS; RUTHENIUM AB Ferrous ions are found to catalyze the photochemical reduction of CO2 to CO in acetonitrile (ACN) solutions containing triethylamine (TEA) or triethanolamine (TEOA) as reductive quenchers and p-terphenyl (TP) as a photosensitizer. TP is photoreduced to form the radical anion, TP.-, which reduces Fe(II) ions. The rate constant for the reduction of Fe(II) by TP.- was determined by pulse radiolysis in ACN/TEOA solutions and found to be (1.2 +/- 0.4) x 10(8) L mol(-1) s(-1). The Fe(I) ions produced are expected to react with CO2 to form an adduct that is equivalent to the adduct known to be formed upon reaction of CO2.- with Fe(II) complexes. Subsequent reduction of the Fe-CO2 adduct leads to formation of CO. Fe(I) can also undergo protonation and form H-2. After extensive irradiation, photochemical production of CO stops, probably due to competition between CO and CO2 for the Fe(I) binding sites. Addition of CO to the solution enhances the photochemical production of H-2. C1 NIST, Phys & Chem Properties Div, Gaithersburg, MD 20899 USA. RP Neta, P (reprint author), NIST, Phys & Chem Properties Div, Gaithersburg, MD 20899 USA. NR 30 TC 27 Z9 27 U1 0 U2 27 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 MAY 18 PY 2000 VL 104 IS 19 BP 4475 EP 4479 DI 10.1021/jp993456f PG 5 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 313MJ UT WOS:000087003200018 ER PT J AU Mardis, KL Brune, RJ Vishwanath, P Giorgis, B Payne, GF Gilson, MK AF Mardis, KL Brune, RJ Vishwanath, P Giorgis, B Payne, GF Gilson, MK TI Intramolecular versus intermolecular hydrogen bonding in the adsorption of aromatic alcohols onto an acrylic ester sorbent SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID PARTITION-COEFFICIENTS; MOLECULAR MECHANICS; CARBON-DIOXIDE; AB-INITIO; CONFORMATIONS; DERIVATIVES; SOLVATION; DYNAMICS; ENERGIES; PROTEINS AB Intramolecular hydrogen bonds influence intermolecular binding in adsorption and molecular recognition, but the interplay between intra- and intermolecular hydrogen bonding is poorly understood. In this study, a series of four aromatic alcohols, 2-phenylethanol, 3-phenyl-1-propanol, 2-phenoxyethanol, and 3-phenoxy-1-propanol, are examined to determine the effect of intramolecular hydrogen bond formation on the binding to ethyl propionate (EP), an analogue of an acrylic ester separation resin. A combination of infrared spectroscopy, molecular modeling, and ab initio calculations are used to investigate the conformational preferences of the alcohols and the alcohol:EP complexes in hexane. Without EP, 2-phenylethanol and 2-phenoxyethanol prefer intramolecularly hydrogen-bonded conformations, whereas 3-phenyl-1-propanol overwhelmingly favors a conformer without an intramolecular hydrogen bond. For 3-phenoxy-1-propanol, there is a smaller preference for conformers without an intramolecular hydrogen bond. These results agree qualitatively with the experimentally measured IR spectra. The conformational preferences are explained by examining the energy components of low-energy conformers. Electrostatic interactions favor the intramolecularly hydrogen-bonded species, whereas the dihedral energy term and entropic term favor conformers without an intramolecular hydrogen bond. The balance determines the most stable conformer. The calculations predict that all four alcohols bind EP weakly compared with para-methoxyphenol, This ranking is in good agreement with experimental, adsorption measurements. The small calculated Delta G degrees values of approximate to -0.9 to -2.4 kJ/mol for the alcohols is explained in terms of hydrogen bond donating ability, entropy, and the competition between inter- and intramolecular hydrogen bonds. C1 Natl Inst Standards & Technol, Ctr Adv Res Biotechnol, Rockville, MD 20850 USA. Univ Maryland Baltimore Cty, Dept Chem & Biochem Engn, Baltimore, MD 21250 USA. Univ Maryland Baltimore Cty, Agr Biotechnol Ctr, Baltimore, MD 21250 USA. RP Gilson, MK (reprint author), Natl Inst Standards & Technol, Ctr Adv Res Biotechnol, 9600 Gudelsky Dr, Rockville, MD 20850 USA. EM gilson@umbi.umd.edu OI Mardis, Kristy/0000-0003-2633-9304 NR 28 TC 19 Z9 21 U1 1 U2 6 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 MAY 18 PY 2000 VL 104 IS 19 BP 4735 EP 4744 DI 10.1021/jp993531m PG 10 WC Chemistry, Physical SC Chemistry GA 313MP UT WOS:000087003700024 ER PT J AU Lacourciere, KA Stivers, JT Marino, JP AF Lacourciere, KA Stivers, JT Marino, JP TI Mechanism of neomycin and Rev peptide binding to the Rev responsive element of HIV-1 as determined by fluorescence and NMR spectroscopy SO BIOCHEMISTRY LA English DT Article ID BACTERIOPHAGE-T4 DNA-POLYMERASE; T7 RNA-POLYMERASE; AMINOGLYCOSIDE ANTIBIOTICS; MESSENGER-RNA; 2-AMINOPURINE FLUORESCENCE; RIBOSOMAL-RNA; ALPHA-HELIX; RRE RNA; A-SITE; PROTEIN AB Rev is an essential HIV-I regulatory protein that binds the Rev responsive element (RRE) within the env gene of the HIV-1 RNA genome and is involved in transport of unspliced or partially spliced viral mRNA from the cell nucleus to the cytoplasm. Previous studies have shown that a short a-helical peptide derived from Rev (Rev 34-50), and a truncated form of the RRE sequence provide a useful in vitro system to study this interaction while still preserving the essential aspects of the native complex. We have selectively incorporated the fluorescent probe 2-aminopurine 2'-O-methylriboside (2-AP) into the RRE sequence in nonperturbing positions (A68 and U72) such that the binding of both Rev peptide and aminoglycoside ligands could be characterized directly by fluorescence methods. Rev peptide binding to the RRE-72AP variant resulted in a 2-fold fluorescence increase that provided a useful signal to monitor this binding interaction (K-D = 20 +/- 7 nM). Using stopped-flow kinetic measurements, we have shown that specific Rev peptide binding occurs by a two-step process involving diffusion-controlled encounter, followed by isomerization of the RNA. Using the RRE-68AP and -72AP constructs, three classes of binding sites for the aminoglycoside neomycin were unambiguously detected. The first site is noninhibitory to Rev binding (K-D = 0.24 +/- 0.040 mu M), the second site inhibited Rev binding in a competitive fashion (K-D = 1.8 +/- 0.8 mu M), and the third much weaker site (or sites) is attributed to nonspecific binding (K-D greater than or equal to 40 mu M). Complementary NMR measurements have shown that neomycin forms both a specific binary complex with RRE and a specific ternary complex with RRE and Rev. NMR data further suggest that neomycin occupies a similar high-affinity binding site in both the binary and tertiary complexes, and that this site is located in the lower stem region of RRE. C1 Univ Maryland, Maryland Biotechnol Inst, Ctr Adv Res Biotechnol, Rockville, MD 20850 USA. Natl Inst Stand & Technol, Rockville, MD 20850 USA. RP Marino, JP (reprint author), Univ Maryland, Maryland Biotechnol Inst, Ctr Adv Res Biotechnol, 9600 Gudelsky Dr, Rockville, MD 20850 USA. FU NIGMS NIH HHS [R01 GM056834, GM51265] NR 57 TC 95 Z9 96 U1 1 U2 6 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0006-2960 J9 BIOCHEMISTRY-US JI Biochemistry PD MAY 16 PY 2000 VL 39 IS 19 BP 5630 EP 5641 DI 10.1021/bi992932p PG 12 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 313ME UT WOS:000087002800002 PM 10801313 ER PT J AU Baum, BA Soulen, PF Strabala, KI King, MD Ackerman, SA Menzel, WP Yang, P AF Baum, BA Soulen, PF Strabala, KI King, MD Ackerman, SA Menzel, WP Yang, P TI Remote sensing of cloud properties using MODIS airborne simulator imagery during SUCCESS 2. Cloud thermodynamic phase SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID CIRRUS CLOUDS; WATER-VAPOR; MU-M; RADIATIVE PROPERTIES; SPECTROMETER; WINDOW; REGION; ICE AB Methods to infer cloud thermodynamic phase (ice or water) are investigated using multispectral imagery. An infrared (IR) trispectral algorithm using the 8.52-, 11-, and 12-mu m bands [Ackerman et al., 1990; Strabala et al., 1994] forms the basis of this work and will be applied to data from the Earth Observing System (EOS) Moderate-Resolution Imaging Spectroradiometer (MODIS) instrument. Since the algorithm uses IR bands, it can be applied to either daytime or nighttime data and is not sensitive to the presence of cloud shadows. A case study analysis is performed with a MODIS airborne simulator (MAS) scene collected during the Subsonic Aircraft Contrail and Cloud Effects Special Study (SUCCESS) on April 21, 1996, at 2000 UTC. The scene under scrutiny is quite complex, containing low-level broken water clouds, cirrus cells, cloud shadows, subvisual cirrus, and contrails. The IR trispectral algorithm is found to be less accurate in (1) regions where more than one cloud phase type occurs and (2) regions of thin cirrus overlying a lower-level cloud layer. To improve the phase retrieval accuracy in these areas of difficulty, additional bands located at 0.65, 1.63, and 1.90 mu m are incorporated, Radiative transfer (RT) calculations are performed to simulate the MAS bands using the cirrus and water cloud models detailed by Baum et al. [this issue]. The RT calculations are performed for singlelayer cirrus- and water-phase clouds as well as for the case of thin cirrus overlying a lower-level water droplet cloud. Both modeled results and application of the theory to a case study suggest that the cloud thermodynamic phase retrieval accuracy can be improved by inclusion of the visible and near infrared bands. C1 NASA, NESDIS, Adv Satellite Prod Team, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Maryland, Joint Ctr Earth Syst Technol, Catonsville, MD 21228 USA. Sci Syst & Applicat Inc, Lanham, MD 20706 USA. RP Baum, BA (reprint author), NASA, CIMSS, 1225 W Dayton St, Madison, WI 53706 USA. EM bryan.baum@ssec.wisc.edu RI Menzel, W. Paul/B-8306-2011; Yang, Ping/B-4590-2011; King, Michael/C-7153-2011; Ackerman, Steven/G-1640-2011; Baum, Bryan/B-7670-2011 OI Menzel, W. Paul/0000-0001-5690-1201; King, Michael/0000-0003-2645-7298; Ackerman, Steven/0000-0002-4476-0269; Baum, Bryan/0000-0002-7193-2767 NR 23 TC 102 Z9 110 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 MAY 16 PY 2000 VL 105 IS D9 BP 11781 EP 11792 DI 10.1029/1999JD901090 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 315RA UT WOS:000087125700020 ER PT J AU Angell, JK AF Angell, JK TI Tropospheric temperature variations adjusted for El Nino, 1958-1998 SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID SOUTHERN OSCILLATION; DECADAL VARIABILITY; CLIMATE-CHANGE; PACIFIC-OCEAN; TRENDS; FREQUENCY; SIGNAL AB The El Nino-Southern Oscillation (ENSO) is not an extrinsic forcing mechanism on the atmosphere, so its impact thereon cannot be cleanly removed. Nevertheless, it is of interest to estimate what atmospheric temperatures would have been if ENSO had not been operating. This is done here by using a 63-station global radiosonde network to find the relation, for the period 1958-1998, between sea-surface temperature (SST) in the El Nino region of the eastern equatorial Pacific (Nino3 SST) and tropospheric (850-300 mbar) temperature, Seasonal lag correlations for the 41-year interval show maximum (and significant) correlations of 0.67, 0.57, and 0.34 between Nino3 SST and the 850 to 300-mbar temperature in tropics, globe, and north temperate zone, respectively, two seasons later. Accordingly, the annual 850 to 300-mbar temperatures for those regions are adjusted (effect of Nino3 SST on them minimized) by means of the linear least squares relation between the annual values of 850 to 300-mbar temperature and annual values of Nino3 SST shifted two seasons earlier, omitting the years 1964, 1983, and 1992 following Agung, El Chichon, and Pinatubo eruptions, as well as the anomalously warm year of 1998. In 1998 the global 850 to 300-mbar temperature is a record 0.7 K above the 1961-1990 average but, after adjustment in the above manner for the strong 1997-1998 El Nino, only 0.2 K above this average and the twelfth warmest year of record. During 1958-1998 the global 850 to 300-mbar layer warms by 0.10 K/decade, but after adjustment for ENSO events the warming is 0.07 K/decade, so that about one third of the global tropospheric warming is related to ENSO. The adjustment provides a different perspective on the significance of anomalously warm years, as well as warming trends, to the issue of climate change. C1 NOAA, Air Resources Lab, Silver Spring, MD 20910 USA. RP Angell, JK (reprint author), NOAA, Air Resources Lab, SSMC3,Room 3151,1315 East West Highway, Silver Spring, MD 20910 USA. NR 29 TC 25 Z9 27 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD MAY 16 PY 2000 VL 105 IS D9 BP 11841 EP 11849 DI 10.1029/2000JD900044 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 315RA UT WOS:000087125700025 ER PT J AU Breon, FM Jackson, DL Bates, JJ AF Breon, FM Jackson, DL Bates, JJ TI Calibration of the Meteosat water vapor channel using collocated NOAA/HIRS 12 measurements SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID RADIOSONDE; SATELLITE; MODEL; VALIDATION; INVERSION; RADIANCES; HUMIDITY AB The Meteosat geostationary satellites carry a filtered radiometer channel centered at 6.2 mu m for the measurement of upper tropospheric humidity. The opetational calibration is derived from radiative transfer calculations applied to radiosonde measurements; large fluctuations in the calibration have been noticed. Here, we apply another method based on collocations with NOAA/High-Resolution Infrared Radiometer Sounder (HIRS) channel 12. Radiative transfer calculations show that Meteosat measurements can be accurately predicted from HIRS channel 12 brightness temperatures. In addition, the HIRS instrument has onboard calibration of the complete optics, which makes it suitable as a reference for the calibration of other spaceborne radiometers. Application of the method to 3 years of Meteosat-5 data shows calibration fluctuations significantly smaller than those provided by the operational method. This result indicates that the short-term stability of the instrument calibration is much better than 5%, the variability given by the operational calibration. The proposed calibration coefficient is smaller by about 10-15%, which results in equivalent brightness temperatures biased by about 3-4 K and 35-50% relative error on the upper tropospheric humidity. Hypotheses of the causes for such large differences between the two calibration procedure results are proposed. C1 Univ Colorado, Cooperat Inst Res Environm Sci, Climate Diagnost Ctr, Boulder, CO 80302 USA. NOAA, ERL, CDC, Boulder, CO 80303 USA. RP Breon, FM (reprint author), CEA, DSM, Lab Sci Climat & Environm, F-91191 Gif Sur Yvette, France. EM fmbreon@cea.fr; jbates@etl.noaa.gov RI Bates, John/D-1012-2009; Jackson, Darren/D-5506-2015; Breon, Francois-Marie/M-4639-2016 OI Bates, John/0000-0002-8124-0406; Jackson, Darren/0000-0001-5211-7866; Breon, Francois-Marie/0000-0003-2128-739X NR 17 TC 23 Z9 23 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 MAY 16 PY 2000 VL 105 IS D9 BP 11925 EP 11933 DI 10.1029/2000JD900031 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 315RA UT WOS:000087125700032 ER PT J AU Li, L Meuse, C Silin, V Gaigalas, AK Zhang, YZ AF Li, L Meuse, C Silin, V Gaigalas, AK Zhang, YZ TI Application of electromodulated fluorescence to the study of the dynamics of Alexa 488 fluorochrome immobilized on a gold electrode SO LANGMUIR LA English DT Article ID SELF-ASSEMBLED MONOLAYERS; SURFACE; ADSORPTION; INTERFACE; SPECTROSCOPY; AU(111) AB Alexa 488 fluorochrome was immobilized on a gold electrode. The formation of the layer of fluorochrome was followed in real time using surface plasmon resonance (SPR). Both SPR and spectroscopic ellipsometry (SE) gave a thickness of similar to 0.7 nm for the fluorochrome layer. SE showed a strong optical absorption peak at 512 nm which is red-shifted relative to the absorption peak at 490 nm for fluorochrome in solution. The electromodulated fluorescence (EmF) intensity was measured and found to be predominantly out-of-phase with the modulating potential. The amplitude of the EmF depended inversely on the modulating frequency and was large only for frequencies less than 5 Hz. The EmF amplitude had a large dependence on solution ionic strength. Measurements of the electromodulated reflectance (EmR) indicated minimal changes in absorbency so that the EmF was most likely due to quantum yield modulation We assumed that the underlying cause of the fluorescence modulation was local surface reorganization, which led to changes in the separation between the surface and the fluorochrome. The EmF response was described by a model which assumed that the fluorochrome had two locations relative to the surface, and a potential-dependent rate constant described the transition between the two locations. The rate constant was found to be less than 0.002 s(-1). We also considered a second model which assumed fluorochrome electrophoretic transport. The transport model did not reproduce the measured EmF response. Electron transfer from the excited state was also considered. C1 Natl Inst Stand & Technol, Div Biotechnol, Gaithersburg, MD 20899 USA. Mol Probes Inc, Eugene, OR 97402 USA. RP Gaigalas, AK (reprint author), Natl Inst Stand & Technol, Div Biotechnol, Gaithersburg, MD 20899 USA. NR 21 TC 7 Z9 7 U1 2 U2 4 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0743-7463 J9 LANGMUIR JI Langmuir PD MAY 16 PY 2000 VL 16 IS 10 BP 4672 EP 4677 PG 6 WC Chemistry, Multidisciplinary; Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA 313NR UT WOS:000087006200041 ER PT J AU Krishnamoorti, R Silva, AS Modi, MA Hammouda, B AF Krishnamoorti, R Silva, AS Modi, MA Hammouda, B TI Small-angle neutron scattering study of a cylinder-to-sphere order-order transition in block copolymers SO MACROMOLECULES LA English DT Article ID DISORDER TRANSITION; TRIBLOCK COPOLYMERS; CUBIC PHASE; DIBLOCK; STABILITY; KINETICS; MELT; MICRODOMAINS; FLUCTUATIONS; RHEOLOGY AB The pathway and kinetics of the order-order transition from shear-aligned cylindrical microdomains to spheres arranged on a bcc lattice in a highly asymmetrical block copolymer are monitored using small-angle neutron scattering (SANS). Shear-aligned hexagonally closed-packed cylindrical microdomains were heated to the spherical microdomain region under quiescent conditions, and the microstructure evolution associated with the order-order transition was followed by SANS. The data indicate a rapid decrease in the cylindrical microdomain order and a gradual rise in the signatures associated with the spherical microdomains, thereby suggesting the existence of an intermediate state where the sample is poorly ordered. The duration of this intermediate state increases with increasing distance from the order-order transition and is consistent with previous rheological measurements on unaligned wormlike cylinders. The results of the scattering measurements are compared to the predictions of recent theories describing the cylinder-to-sphere transition. C1 Univ Houston, Dept Chem Engn, Houston, TX 77204 USA. Natl Inst Stand & Technol, Ctr Neutron Res, Gaithersburg, MD 20899 USA. RP Krishnamoorti, R (reprint author), Univ Houston, Dept Chem Engn, Houston, TX 77204 USA. RI Krishnamoorti, Ramanan/F-7914-2011 OI Krishnamoorti, Ramanan/0000-0001-5831-502X NR 22 TC 39 Z9 40 U1 3 U2 10 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0024-9297 J9 MACROMOLECULES JI Macromolecules PD MAY 16 PY 2000 VL 33 IS 10 BP 3803 EP 3809 DI 10.1021/ma991842p PG 7 WC Polymer Science SC Polymer Science GA 315YB UT WOS:000087139600045 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 alumina suspensions using ammonium poly(methacrylate) SO COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS LA English DT Article DE alpha-alumina; ammonium poly(methacrylate) (APMA); adsorption; hydrogen bonding; electrokinetics; electrostatic and chemical interaction ID POLY-ELECTROLYTE ADSORPTION; POLYACRYLIC-ACID; LATTICE THEORY; POLYELECTROLYTES; IONS AB The interaction of alpha-alumina with ammonium poly(methacrylate) (APMA) has been investigated through adsorption and electrokinetic measurements. The adsorption isotherms exhibit high affinity, Langmuirian behaviour at highly acidic pH and the adsorption density is found to decrease with increasing pH. On the contrary, the percentage desorption increases with increasing pH. Electrokinetic studies indicate specific adsorption between alumina and APMA resulting in a shift of the isoelectric point to acidic pH values. Electrophoretic mobility values indicate that the alumina suspension could be well dispersed in the pH range 5-11, consequent to polymer adsorption. These results were corroborated by the dispersion tests. Dissolution tests reveal the release of aluminium species from alumina while co-precipitation experiments confirm the chemical interaction of aluminium species with APMA in the bulk solution. Hydrogen bonding, electrostatic and chemical interactive forces are postulated to govern the adsorption process. FTIR spectroscopic data lend further support to the interaction mechanisms proposed. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Indian Inst Sci, Dept Met, Bangalore 560012, Karnataka, India. Natl Inst Stand & Technol, Div Ceram, Gaithersburg, MD 20899 USA. RP Natarajan, KA (reprint author), Indian Inst Sci, Dept Met, Bangalore 560012, Karnataka, India. NR 28 TC 25 Z9 26 U1 1 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0927-7757 J9 COLLOID SURFACE A JI Colloid Surf. A-Physicochem. Eng. Asp. PD MAY 15 PY 2000 VL 164 IS 2-3 BP 143 EP 154 DI 10.1016/S0927-7757(99)00347-7 PG 12 WC Chemistry, Physical SC Chemistry GA 288VV UT WOS:000085585900006 ER PT J AU Short, JW Bruce, AW AF Short, JW Bruce, AW TI Repose to comment on "Natural hydrocarbon background in benthic sediments of Prince William Sound, Alaska: Oil vs coal" SO ENVIRONMENTAL SCIENCE & TECHNOLOGY LA English DT Letter ID SPILL C1 NOAA, Auke Bay Lab, Alaska Fisheries Sci Ctr, Natl Marine Fisheries Serv, Juneau, AK 99801 USA. US Geol Survey, Menlo Park, CA 94025 USA. RP Short, JW (reprint author), NOAA, Auke Bay Lab, Alaska Fisheries Sci Ctr, Natl Marine Fisheries Serv, 11305 Glacier Highway, Juneau, AK 99801 USA. NR 8 TC 2 Z9 2 U1 0 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0013-936X J9 ENVIRON SCI TECHNOL JI Environ. Sci. Technol. PD MAY 15 PY 2000 VL 34 IS 10 BP 2066 EP 2067 DI 10.1021/es002001x PG 2 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA 314RT UT WOS:000087071900030 ER PT J AU Chan, LY Chan, CY Liu, HY Christopher, S Oltmans, SJ Harris, JM AF Chan, LY Chan, CY Liu, HY Christopher, S Oltmans, SJ Harris, JM TI A case study on the biomass burning in southeast Asia and enhancement of tropospheric ozone over Hong Kong SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID FIRE AB Substantial enhancement of ozone was frequently observed in the lower troposphere (2.5-6.0 km) over Hong Kong (22.2 degrees N, 114.3 degrees E). Most of these enhanced ozone layers (with peak concentration up to 138 ppbv) feature moderate and high relative humidity (50-100%) and a temperature inversion at the bottom of the layer. These phenomena predominantly occur in spring (late February to mid April) coinciding with the dry season in Southeast Asia. Back air trajectories showed that these ozone-rich air masses had passed through the Indo-Burma region of Southeast Asia, where large-scale fires were recorded at the time. A case study is presented and evidence from the fire count derived from AVHRR satellite images and carbon monoxide concentration derived from space shuttle during the MAPS experiment was used. We have illustrated with this case study that biomass-burning emissions are the source of the elevated ozone observed. C1 Hong Kong Polytech Univ, Dept Civil & Struct Engn, Hung Hom, Hong Kong, Peoples R China. Univ Alabama, Dept Atmospher Sci, Huntsville, AL 35899 USA. NOAA, Climate Monitoring & Diagnost Lab, Boulder, CO 80303 USA. RP Chan, LY (reprint author), Hong Kong Polytech Univ, Dept Civil & Struct Engn, Hung Hom, Hong Kong, Peoples R China. RI Liu, Hongyu/A-5867-2008; Christopher, Sundar/E-6781-2011 NR 10 TC 35 Z9 44 U1 1 U2 7 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD MAY 15 PY 2000 VL 27 IS 10 BP 1479 EP 1482 DI 10.1029/1999GL010855 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 314NK UT WOS:000087062000014 ER PT J AU Knopp, KJ Mirin, RP Bertness, KA Silverman, KL Christensen, DH AF Knopp, KJ Mirin, RP Bertness, KA Silverman, KL Christensen, DH TI Compound semiconductor oxide antireflection coatings SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID VERTICAL-CAVITY LASERS; OXIDATION; CONSTANTS; SURFACE AB We report the development of high quality, broad-bandwidth, antireflection (AR) coatings using the low index provided by wet thermally oxidized Al0.98Ga0.02As. We address the design criteria, fabrication, and characterizations of AR coatings composed of surface and buried oxide layers on GaAs. We show, using native-oxide dispersion data, that surface oxide coatings can be designed to offer a nearly zero minimum of reflectance and a reflectance of < 1% over bandwidths as large as 500 nm. Surface coatings having a reflectance minimum of 0.4% and a reflectance of < 1% over > 250 nm have been experimentally demonstrated at a design wavelength of 1 micrometer. Additionally, buried oxide coatings can be designed with an AlxGa1-xAs matching layer of any composition to exactly match the admittance of any substrate with effective index between 2.5 and 3.5. We have demonstrated buried oxide coatings, also designed for 1 micrometer, having a reflectance minimum of 0.4% and a reflectance of < 1% over 21 nm. The calculated optical scattering loss from measured roughness data indicates that reflectance minima as low as 10(-4) % are ultimately achievable with native-oxide antireflection coatings. [S0021-8979(00)01709-6]. C1 Natl Inst Stand & Technol, Boulder, CO 80303 USA. RP Knopp, KJ (reprint author), Natl Inst Stand & Technol, 325 Broadway MS 81504, Boulder, CO 80303 USA. OI Mirin, Richard/0000-0002-4472-4655 NR 17 TC 5 Z9 5 U1 0 U2 2 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD MAY 15 PY 2000 VL 87 IS 10 BP 7169 EP 7175 DI 10.1063/1.372965 PG 7 WC Physics, Applied SC Physics GA 308TY UT WOS:000086730000005 ER PT J AU Gaffen, DJ Sargent, MA Habermann, RE Lanzante, JR AF Gaffen, DJ Sargent, MA Habermann, RE Lanzante, JR TI Sensitivity of tropospheric and stratospheric temperature trends to radiosonde data quality SO JOURNAL OF CLIMATE LA English DT Article ID NORTHERN-HEMISPHERE; CLIMATE DATA; SURFACE; SATELLITES; RECORDS; ERRORS; CARDS; OZONE; MB AB Radiosonde data have been used, and will likely continue to be used, for the detection of temporal trends in tropospheric and lower-stratospheric temperature. However, the data are primarily operational observations, and it is not clear that they are of sufficient quality for precise monitoring of climate change. This paper explores the sensitivity of upper-air temperature trend estimates to several data quality issues. Many radiosonde stations do not have even moderately complete records of monthly mean data for the period 1959-95. In a network of 180 stations (the combined Global Climate Observing System Baseline Upper-Air Network and the network developed by J. K. Angell), only 74 stations meet the data availability requirement of at least 85% of nonmissing months of data for tropospheric levels (850-100 hPa). Extending into the lower stratosphere (up to 30 hPa), only 22, stations have data records meeting this requirement for the same period, and the 30-hPa monthly data are generally based on fewer daily observations than at 50 hPa and below. These networks show evidence of statistically significant tropospheric warming, particularly in the Tropics, and stratospheric cooling for the period 1959-95. However, the selection of different station networks can cause network-mean trend values to differ by up to 0.1 K decade(-1). The choice of radiosonde dataset used to estimate trends influences the results. Trends at individual stations and pressure levels differ in two independently produced monthly mean temperature datasets. The differences are generally less than 0.1 K decade(-1), but in a few cases they are larger and statistically significant at the 99% confidence level. These cases are due to periods of record when one dataset has a distinct bias with respect to the other. The statistical method used to estimate linear trends has a small influence on the result. The nonparametric median of pairwise slopes method and the parametric least squares linear regression method tend to yield very similar, but not identical, results with differences generally less than +/-0.03 K decade(-1) for the period 1959-95. However, in a few instances the differences in stratospheric trends for the period 1970-95 exceed 0.1 K decade(-1). Instrument changes can lead to abrupt changes in the mean, or change-points, in radiosonde temperature data records, which influence trend estimates. Two approaches to removing change-points by adjusting radiosonde temperature data were attempted. One involves purely statistical examination of time series to objectively identify and remove multiple change-points. Methods of this type tend to yield similar results about the existence and timing of the largest change-points, but the magnitude of detected change-points is very sensitive to the particular scheme employed and its implementation. The overwhelming effect of adjusting time series using the purely statistical schemes is to remove the trends, probably because some of the detected change-points are not spurious signals but represent real atmospheric change. The second approach incorporates station history information to test specific dates of instrument changes as potential change-points, and to adjust time series only if there is agreement in the test results for multiple stations. This approach involved significantly fewer adjustments to the time series, and their effect was to reduce tropospheric warming trends (or enhance tropospheric cooling) during 1959-95 and (in the case of one type of instrument change) enhance stratospheric cooling during 1970-95. The trends based on the adjusted data were often statistically significantly different from the original trends at the 99% confidence level. The intent here was not to correct or improve the existing time series, but to determine the sensitivity of trend estimates to the adjustments. Adjustment for change-points can yield very different time series depending on the scheme used and the manner in which it is implemented, and trend estimates are extremely sensitive to the adjustments. Overall, trends are more sensitive to the treatment of potential change-points than to any of the other radiosonde data quality issues explored. C1 NOAA, Air Resources Lab, Silver Spring, MD 20910 USA. Univ Maryland, Dept Math, College Pk, MD 20742 USA. NOAA, Natl Geophys Data Ctr, Boulder, CO 80303 USA. Princeton Univ, NOAA, Geophys Fluid Dynam Lab, Princeton, NJ 08544 USA. RP Gaffen, DJ (reprint author), NOAA, Air Resources Lab, R-ARL,1315 East West Highway, Silver Spring, MD 20910 USA. NR 53 TC 94 Z9 98 U1 1 U2 11 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 MAY 15 PY 2000 VL 13 IS 10 BP 1776 EP 1796 DI 10.1175/1520-0442(2000)013<1776:SOTAST>2.0.CO;2 PG 21 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 319PJ UT WOS:000087350100010 ER PT J AU Mapes, BE AF Mapes, BE TI Convective inhibition, subgrid-scale triggering energy, and stratiform instability in a toy tropical wave model SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID PACIFIC WARM POOL; EQUATORIAL WESTERN PACIFIC; SHALLOW-WATER MODEL; TOGA COARE; THERMODYNAMIC CHARACTERISTICS; CUMULUS PARAMETRIZATION; CLOUD CLUSTERS; SQUALL-LINE; MESOSCALE; CIRCULATIONS AB A toy model of large-scale deep convection variations is constructed around a radiative-convective equilibrium climate, with an observed mean sounding as its thermodynamic basic state. Vertical structure is truncated at two modes, excited by convective (one-signed) and stratiform (two-signed) beating processes in tropical deep convection. Separate treatments of deep and shallow convection ale justified by observations that deep convection is more variable. Deep convection intensity is assumed to be modulated by convective available potential energy (CAPE), while occurence frequency is modulated by the ratio of convective inhibition (CIN) to "triggering energy" It: a scalar representing the intensity of subgrid-scale fluctuations. Deep convective downdrafts cool and dry the boundary layer but also increase K. Variations of Ii make the relationship between convection and thermodynamic variables (CAPE, GIN, theta(e)) nonunique and amplify the deep convective response to temperature waves of small (similar to 1 degrees C) amplitude. For a parameter set in which CAPE varions control convection, moist convective damping destroys all variability. When CIN/K variations have dominant importance (the "inhibition-controlled" regime), a mechanism termed "stratiform instability" generates large-scale waves. This mechanism involves lower tropospheric cooling by stratiform precipitation, which preferentially occurs where the already cool lower troposphere favors deep convection, via smaller CIM. Stratiform instability has two subregimes, based on the relative importance of the two opposite effects of downdrafts: When boundary layer theta(e), reduction (a local negative feedback) is stronger, small-scale waves with frequency based on the boundary layer recovery time are preferred. When the K-generation effect (positive feedback) is stronger, very large scales (low wavenumbers of the domain) develop. A mixture of these scales occurs for parameter choices based on observations. Model waves resemble observed waves, with a phase speed similar to 20 m s(-1) (near the dry wave speed of the second internal mode), and a "cold boomerang vertical temperatures structure. Although ii exhibits "quasi-equilibrium'' with other convection variables (correlations > 0.99), replacing the prognostic K equation with diagnostic equations based on these relationships can put the model into wildly different regimes, if small time lags indicative of causality are distorted. The response of model convection to climatological spatial anomalies of theta(e), (proxy For SST) and K (proxy For orographic and coastal triggering) is considered. Higher SST tends broadly to favor convection under either CAPE-controlled or inhibition-controlled regimes, but there: are dynamical embellishments in the inhibition-controlled regime. The Kelvin wave seems to be the preferred structure when the model is run on a uniform equatorial beta plane. C1 NOAA, CIRES Climate Diagnost Ctr, Boulder, CO 80303 USA. RP Mapes, BE (reprint author), NOAA, CIRES Climate Diagnost Ctr, 325 Broadway R-E-CDI, Boulder, CO 80303 USA. EM bem@cdc.noaa.gov RI Mapes, Brian/A-5647-2010 NR 51 TC 215 Z9 218 U1 2 U2 10 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 MAY 15 PY 2000 VL 57 IS 10 BP 1515 EP 1535 DI 10.1175/1520-0469(2000)057<1515:CISSTE>2.0.CO;2 PG 21 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 314UL UT WOS:000087075900003 ER PT J AU Lu, CG Browning, GL AF Lu, CG Browning, GL TI Discontinuous forcing generating rough initial conditions in 4DVAR data assimilation SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID VARIATIONAL DATA ASSIMILATION; PARAMETERIZED DISCONTINUITIES; GENERALIZED ADJOINT; PHYSICAL PROCESSES; PRECIPITATION DATA; TIME SCALES; IMPACT; MODEL AB The impact of discontinuous model forcing on the initial conditions obtained from 4DVAR data assimilation is studied with mathematic analyses, idealized numerical examples, and more realistic meteorological cases. The results show that a discontinuity in a parameterization, like a model bias, can introduce a systematic error in the assimilated initial fields. However, the most detrimental effect of a model discontinuity is the retention of roughness in the assimilated initial fields, although in some cases the 4DVAR procedure provides some smoothing effect. The obvious consequences of this roughness is that it will introduce spurious modes in the ensuing forecast, and derivatives of the assimilated initial data will be unrealistically large, which can lead to large errors in data analysis. The smoothing effect on the initial conditions with the addition of artificial diffusion to the constraining model is also studied. Possible solutions to the problem of 4DVAR data assimilation with discontinuous model forcing are discussed. C1 NOAA, ERL, R E FS, Forecast Syst Lab, Boulder, CO 80303 USA. Colorado State Univ, Cooperat Inst Res Atmosphere, Ft Collins, CO 80523 USA. RP Lu, CG (reprint author), NOAA, ERL, R E FS, Forecast Syst Lab, 325 Broadway, Boulder, CO 80303 USA. NR 19 TC 6 Z9 7 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 MAY 15 PY 2000 VL 57 IS 10 BP 1646 EP 1656 DI 10.1175/1520-0469(2000)057<1646:DFGRIC>2.0.CO;2 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 314UL UT WOS:000087075900011 ER PT J AU Hsueh, CH Fuller, ER AF Hsueh, CH Fuller, ER TI Residual stresses in thermal barrier coatings: effects of interface asperity curvature/height and oxide thickness SO MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING LA English DT Article DE residual stresses; coating; numerical simulations; analytical modeling ID OXIDATION-INDUCED STRESSES; SCALES; BEHAVIOR; SUBSTRATE; SYSTEM; FILMS AB The effects of curvature and height of the interface asperity on residual thermal stresses in a plasma-sprayed thermal barrier coating were numerically simulated. In the lip region of a convex asperity, the residual stress normal to the interface, sigma(y) is tensile in the ceramic top coat and increases with both curvature and height of the asperity. However. this residual tensile stress is lower for a periodic array of asperities than for an isolated asperity. The effects of thickness of the thermally grown oxide at the top coat-bond coat interface on residual thermal stresses were also numerically simulated. In the tip region of a convex asperity, sigma(y) in the ceramic top coat is tensile for a thin oxide but becomes compressive for a thick oxide. In the tip region of a concave asperity, sigma(y) in the ceramic top coat is compressive for a thin oxide and becomes less compressive for a thick oxide. The physical meaning of the above trend was qualitatively interpreted using an analytical model of three concentric circles. Published by Elsevier Science S.A. C1 Oak Ridge Natl Lab, Div Met & Ceram, Oak Ridge, TN 37831 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Hsueh, CH (reprint author), Oak Ridge Natl Lab, Div Met & Ceram, POB 2008, Oak Ridge, TN 37831 USA. RI Hsueh, Chun-Hway/G-1345-2011 NR 23 TC 58 Z9 62 U1 6 U2 22 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 MAY 15 PY 2000 VL 283 IS 1-2 BP 46 EP 55 DI 10.1016/S0921-5093(00)00743-7 PG 10 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA 304HC UT WOS:000086476800006 ER PT J AU Udovic, TJ Huang, Q Erwin, RW Hjorvarsson, B Ward, RCC AF Udovic, TJ Huang, Q Erwin, RW Hjorvarsson, B Ward, RCC TI Structural symmetry of YD3 epitaxial thin films SO PHYSICAL REVIEW B LA English DT Article ID SWITCHABLE OPTICAL-PROPERTIES; LANTHANUM HYDRIDE FILMS; THEORETICAL PREDICTION; NEUTRON-SCATTERING; INSULATING YH3; MAGNETIC-STRUCTURE; CRYSTAL-STRUCTURE; YTTRIUM; DIFFRACTION; TRIFLUORIDE AB A thin-film laminated structure comprised of Pd(5 nm)/Nb(5 nm)/Y(500 nm)/Nb(5 nm) on alpha-Al2O3(110) was synthesized by molecular beam epitaxy to yield a crystalline Y layer with the c axis oriented perpendicular to the growth plane. Neutron diffraction and topographical measurements of the epitaxial YD3 layer formed after deuteriding the Y metal layer were consistent with a twinlike structure possessing P6(3)cm and/or P3 c 1 symmetry. C1 NIST, NIST Ctr Neutron Res, Gaithersburg, MD 20899 USA. Univ Maryland, Dept Mat & Nucl Engn, College Pk, MD 20742 USA. Royal Inst Technol, Dept Mat Phys, S-10044 Stockholm, Sweden. Univ Oxford, Clarendon Lab, Oxford OX1 3PU, England. RP Udovic, TJ (reprint author), NIST, NIST Ctr Neutron Res, 100 Bur Dr,MS 8562, Gaithersburg, MD 20899 USA. RI Hjorvarsson, Bjorgvin/B-3022-2011; OI Hjorvarsson, Bjorgvin/0000-0003-1803-9467 NR 21 TC 36 Z9 36 U1 0 U2 3 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 MAY 15 PY 2000 VL 61 IS 19 BP 12701 EP 12704 DI 10.1103/PhysRevB.61.12701 PG 4 WC Physics, Condensed Matter SC Physics GA 316GK UT WOS:000087159100040 ER PT J AU La Nave, E Scala, A Starr, FW Sciortino, F Stanley, HE AF La Nave, E Scala, A Starr, FW Sciortino, F Stanley, HE TI Instantaneous normal mode analysis of supercooled water SO PHYSICAL REVIEW LETTERS LA English DT Article ID COUPLING THEORY; UNSTABLE MODES; SELF-DIFFUSION; IONIC MELTS; LIQUIDS; DYNAMICS; GLASSES; ENERGY; DEPENDENCE; POINTS AB We use the instantaneous normal mode approach to provide a description of the local curvature of the potential energy surface of a model for water. We focus on the region of the phase diagram in which the dynamics may be described by mode-coupling theory. We find that the diffusion constant depends on the fraction of directions in configuration space connecting different local minima, supporting the hypothesis that the dynamics are controlled by the geometric properties of configuration space. Furthermore, we find a relation between the number of basins accessed in equilibrium and the connectivity between them. C1 Boston Univ, Ctr Polymer Studies, Boston, MA 02215 USA. Boston Univ, Dept Phys, Boston, MA 02215 USA. Univ Rome La Sapienza, Dipartmento Fis, I-00185 Rome, Italy. Univ Rome La Sapienza, INFM, I-00185 Rome, Italy. RP La Nave, E (reprint author), NIST, Div Polymers, Gaithersburg, MD 20899 USA. RI Sciortino, Francesco/B-4768-2012; Starr, Francis/C-7703-2012; Scala, Antonio/A-2098-2012 OI Scala, Antonio/0000-0002-3414-2686 NR 35 TC 74 Z9 75 U1 0 U2 7 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 MAY 15 PY 2000 VL 84 IS 20 BP 4605 EP 4608 DI 10.1103/PhysRevLett.84.4605 PG 4 WC Physics, Multidisciplinary SC Physics GA 313JT UT WOS:000086997100023 ER PT J AU McClelland, JJ Celotta, RJ AF McClelland, JJ Celotta, RJ TI Laser-focused atomic deposition - nanofabrication via atom optics SO THIN SOLID FILMS LA English DT Article; Proceedings Paper CT 3rd International Conference on Molecular Beam Epitaxy-Growth Physics and Technology (MBE-GPT 99) CY MAY 23-28, 1999 CL WARSAW, POLAND SP Polish Vacuum Soc, Polish Crystal Growth Soc, Inst Vacuum Technol, Polish Acad Sci, Inst Phys, Inst Electon Technol, State Comm Sci es DE nano-technology; laser-focused atom deposition; atom optics ID NANOSTRUCTURE FABRICATION; METASTABLE ATOMS; CHROMIUM; LIGHT; LITHOGRAPHY AB In conventional molecular-beam epitaxy, atoms from a diffuse source randomly impinge upon a surface, accumulating in atomic layers or islands. We have recently demonstrated an enhancement of this process, in which the trajectories of the atoms are controlled with nanometer-scale resolution during deposition. Using the forces exerted by laser light tuned near an atomic transition, an array of 'atom lenses' is formed, which focus, or concentrate the atoms into an array of lines or dots with size as small as 30 nm. This new technique represents a novel form of nanofabrication that can create nanometer-scale structures in parallel over a large (millimeter-size) area without the use of any resist or pattern-transfer techniques. (C) 2000 Elsevier Science S.A. All rights reserved. C1 Natl Inst Stand & Technol, Electtron Phys Grp, Gaithersburg, MD 20899 USA. RP McClelland, JJ (reprint author), Natl Inst Stand & Technol, Electtron Phys Grp, Gaithersburg, MD 20899 USA. RI McClelland, Jabez/A-2358-2015 OI McClelland, Jabez/0000-0001-5672-5965 NR 12 TC 12 Z9 12 U1 0 U2 2 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0040-6090 J9 THIN SOLID FILMS JI Thin Solid Films PD MAY 15 PY 2000 VL 367 IS 1-2 BP 25 EP 27 DI 10.1016/S0040-6090(00)00679-9 PG 3 WC Materials Science, Multidisciplinary; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Materials Science; Physics GA 320QU UT WOS:000087412500005 ER PT J AU Wilson, KB Hanson, PJ Baldocchi, DD AF Wilson, KB Hanson, PJ Baldocchi, DD TI Factors controlling evaporation and energy partitioning beneath a deciduous forest over an annual cycle SO AGRICULTURAL AND FOREST METEOROLOGY LA English DT Article DE evaporation; forest floor; energy budget; litter water content; deciduous forest; eddy-covariance; ameriflux ID BROAD-LEAVED FOREST; SEASONAL-VARIATION; PINE FOREST; EVAPOTRANSPIRATION; CO2; EXCHANGE; TRANSPIRATION; CANOPY; FLOOR; MODEL AB The energy balance components were measured above the ground surface of a temperate deciduous forest over an annual cycle using the eddy covariance technique. Over a year, the net radiation at the forest floor was 21.5% of that above the canopy, but this proportion was not constant, primarily because of the distinct phenological stages separated by the emergence and senescence of leaves. The dominant response to seasonal changes in net radiation was through corresponding changes in the sensible heat flux, and both net radiation and sensible heat flux peaked just before leaf emergence. Evaporation at the forest floor was typically less than 0.5 mm per day, and unlike sensible heat flux, was not closely coupled to seasonal changes in net radiation. Instead, evaporation at the forest floor responded primarily to rapid changes in litter water content. Forest floor evaporation was limited by the water-holding capacity of litter, and when the atmospheric demand was large, the litter layer dried on the time scale of several hours. After this rapid period of drying, net radiation and sensible heat flux dominated the energy budget. When leaves were present during the growing season, the sensible and latent energy fluxes at the forest floor were less than 10% of the total canopy fluxes, and the mean Bowen ratio was similar to that above the canopy. However, during the dormant season, the controls of the energy budget at the forest floor largely determine the whole canopy fluxes. On an annual basis, the fluxes from the forest floor are roughly 15-22% of those above the canopy and the evaporation was 86 mm. (C) 2000 Elsevier Science B.V. All rights reserved. C1 NOAA, Atmospher Turbulence & Diffus Div, Oak Ridge, TN 37831 USA. Oak Ridge Natl Lab, Div Environm Sci, Oak Ridge, TN 37831 USA. Univ Calif Berkeley, Dept Environm Sci Policy & Management, Berkeley, CA 94720 USA. RP Wilson, KB (reprint author), NOAA, Atmospher Turbulence & Diffus Div, POB 2456, Oak Ridge, TN 37831 USA. RI Hanson, Paul J./D-8069-2011; Baldocchi, Dennis/A-1625-2009 OI Hanson, Paul J./0000-0001-7293-3561; Baldocchi, Dennis/0000-0003-3496-4919 NR 33 TC 81 Z9 97 U1 3 U2 33 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-1923 J9 AGR FOREST METEOROL JI Agric. For. Meteorol. PD MAY 12 PY 2000 VL 102 IS 2-3 BP 83 EP 103 DI 10.1016/S0168-1923(00)00124-6 PG 21 WC Agronomy; Forestry; Meteorology & Atmospheric Sciences SC Agriculture; Forestry; Meteorology & Atmospheric Sciences GA 305NV UT WOS:000086547800002 ER PT J AU Nevins, SA Siles, BA Nackerdien, ZE AF Nevins, SA Siles, BA Nackerdien, ZE TI Analysis of gamma radiation-induced damage to plasmid DNA using dynamic size-sieving capillary electrophoresis SO JOURNAL OF CHROMATOGRAPHY B LA English DT Article DE plasmids; gamma-radiation; DNA ID SEPARATION; FRAGMENTS AB Bacterial plasmids and the chromosomal DNA of many organisms adopt naturally the negatively supercoiled conformation. Therefore, the irradiation of such plasmids could be used to model conformational changes of chromosomal DNA associated with externally-induced damage. We have applied dynamic size-sieving capillary electrophoresis (CE) to monitor the damage of three DNA plasmids, over an unprecedented base pair (bp) size range (2870-27 500 bp), upon exposure to gamma-radiation (20-400 Gy), Predominantly, CE with UV absorbance detection in the absence of DNA intercalating dyes was employed to preclude undesirable, induced plasmid conformational changes. Plasmid samples and their enzymatic digestion products were analyzed using both CE and slab gel electrophoresis (SGE) in order to verify the conformation of sample components. Relative to SGE, CE analyses revealed more fine structural features of plasmid degradation. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Coll William & Mary, Dept Chem, Williamsburg, VA 23187 USA. Natl Inst Stand & Technol, Div Biotechnol, Gaithersburg, MD 20899 USA. RP Siles, BA (reprint author), Univ Denver, Res Inst, 2050 E Iliff Ave, Denver, CO 80208 USA. NR 19 TC 10 Z9 10 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0378-4347 J9 J CHROMATOGR B JI J. Chromatogr. B PD MAY 12 PY 2000 VL 741 IS 2 BP 243 EP 255 DI 10.1016/S0378-4347(00)00106-7 PG 13 WC Biochemical Research Methods; Chemistry, Analytical SC Biochemistry & Molecular Biology; Chemistry GA 317TG UT WOS:000087242600014 PM 10872594 ER PT J AU Eisenstein, E AF Eisenstein, E TI Experimental approaches for investigating macromolecular interactions SO FASEB JOURNAL LA English DT Meeting Abstract C1 NIST, Ctr Adv Res Biotechnol, Rockville, MD 20850 USA. Univ Maryland, Inst Biotechnol, Rockville, MD 20850 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU FEDERATION AMER SOC EXP BIOL PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3998 USA SN 0892-6638 J9 FASEB J JI Faseb J. PD MAY 11 PY 2000 VL 14 IS 8 MA 1136 BP A1511 EP A1511 PG 1 WC Biochemistry & Molecular Biology; Biology; Cell Biology SC Biochemistry & Molecular Biology; Life Sciences & Biomedicine - Other Topics; Cell Biology GA 313NH UT WOS:000087005401167 ER PT J AU Heimer, TA Heilweil, EJ Bignozzi, CA Meyer, GJ AF Heimer, TA Heilweil, EJ Bignozzi, CA Meyer, GJ TI Electron injection, recombination, and halide oxidation dynamics at dye-sensitized metal oxide interfaces SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID TITANIUM-DIOXIDE FILMS; NANOCRYSTALLINE TIO2; SEMICONDUCTOR-FILMS; CHARGE SEPARATION; STATES; LIGHT AB Time-resolved infrared measurements indicate ultrafast, <350 fs, electron injection from (4,4'dcb)(2)Ru(NCS)(2) (1) and (5,5'dcb)(2)Ru(NCS)(2) (2) to nanostructured TiO2 electrodes (where 4,4'dcb = 4,4'-(COOH)(2)-2,2'-bipyridine). Although rapid, the injection from 2 apparently occurs with a lower quantum yield than that from 1, explaining a lower overall photon-to-current efficiency for 2/TiO2 solar cells. Transient visible spectroscopy reveals similar rates of both halide oxidation and injected electron-oxidized dye recombination for the two sensitizers. Substituting SnO2 for TiO2 increases the electron injection yield from 2 in the case of transparent metal oxide films and improves the photon-to-current efficiency. Results indicate a wavelength-dependent electron injection yield. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Univ Ferrara, Dept Chem, I-44100 Ferrara, Italy. Johns Hopkins Univ, Dept Chem, Baltimore, MD 21218 USA. RP Heilweil, EJ (reprint author), Natl Inst Stand & Technol, 100 Bur Dr,Stop 8441, Gaithersburg, MD 20899 USA. OI Bignozzi, Carlo Alberto/0000-0002-7882-3694 NR 25 TC 219 Z9 219 U1 1 U2 21 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 MAY 11 PY 2000 VL 104 IS 18 BP 4256 EP 4262 DI 10.1021/jp993438y PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 313MH UT WOS:000087003100017 ER PT J AU Redfield, S Linsky, JL AF Redfield, S Linsky, JL TI The three-dimensional structure of the warm local interstellar medium. II. The Colorado model of the local interstellar cloud SO ASTROPHYSICAL JOURNAL LA English DT Article DE circumstellar matter; dust, extinction; infrared : ISM : lines and bands; ISM : abundances; molecular processes ID HIGH-RESOLUTION OBSERVATIONS; D/H RATIO; HST-GHRS; CA-II; SIGHT; GAS; HEMISPHERE; DEUTERIUM; MATTER; LINES AB In this second paper in a series on the structure of the local interstellar medium (LISM), we construct a three-dimensional model of the local interstellar cloud (LIC) based on Hubble Space Telescope (HST), Extreme Ultraviolet Explorer (EUVE), and ground-based Ca II spectra. Starting with hydrogen column densities derived from deuterium column densities measured with the Goddard High Resolution Spectrograph instrument on HST for 16 lines of sight to nearby stars, we derive a model consisting of the sum of nine spherical harmonics that best fit the data. We then rederive the model by including the lines of sight to three hot white dwarfs observed by EUVE and 13 lines of sight with Can column densities at the projected LIC velocity. The LIC model is clearly not a long thin filamentary structure like optical images of some interstellar clouds (e.g., reflection nebulae in the Pleiades), but neither is it spherical in shape. As seen from the north Galactic pole, the LIC is egg-shaped with an axis of symmetry that points in the direction l approximate to 315 degrees. Since the direction of the center of the Scorpius-Centaurus association is l = 320 degrees, the shape of the LIC could be determined by the how of hot gas from Sco-Cen. The model shows that the Sun is located just inside the LIC in the direction of the Galactic center and toward the north Galactic pole. The absence of Mg II absorption at the LIC velocity toward a Cen indicates that the distance to the edge of the LIC in this direction is less than or equal to 0.05 pc and the Sun should cross the boundary between the LIC and the Galactic (G) cloud in less than 3000 yr. We estimate that the volume of the LIC is about 93 pc(3) and its mass is about 0.32 M-circle dot. The physical parameters and hydrogen column density of the LIC are roughly consistent with theoretical models of the warm interstellar medium that assume pressure and ionization equilibrium. However, the empirical hydrogen ionization of the LIC is much higher and the gas temperature lower than the theoretical models predict. Therefore, the ionization is likely due to shock activity from a nearby supernova that has not yet reached equilibrium. The higher ionization increases the gas cooling, which can explain why the gas is 2400 K cooler than the ionization equilibrium models predict. Computed and observed temperatures are in agreement for a model with the observed LIC electron density. C1 Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. NIST, Boulder, CO 80309 USA. RP Redfield, S (reprint author), Univ Colorado, Joint Inst Lab Astrophys, Campus Box 440, Boulder, CO 80309 USA. NR 38 TC 101 Z9 101 U1 1 U2 1 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 MAY 10 PY 2000 VL 534 IS 2 BP 825 EP 837 DI 10.1086/308769 PN 1 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 320ZA UT WOS:000087429400027 ER PT J AU Stivers, JT Nawrot, B Jagadeesh, GJ Stec, WJ Shuman, S AF Stivers, JT Nawrot, B Jagadeesh, GJ Stec, WJ Shuman, S TI Stereochemical outcome and kinetic effects of Rp- and Sp-phosphorothioate substitutions at the cleavage site of vaccinia type I DNA topoisomerase SO BIOCHEMISTRY LA English DT Article ID COVALENT CATALYSIS; ESCHERICHIA-COLI; PHOSPHOLIPASE-C; STRAND CLEAVAGE; MECHANISM; RECOMBINATION; TRANSESTERIFICATION; INTEGRASE; ENZYMES; DOMAIN AB To probe the mechanism of the reversible DNA phosphodiester bond cleavage and religation mechanism of the type I topoisomerase from vaccinia virus, we have synthesized DNA substrates carrying a single nonbridging Rp- or Sp-phosphorothioate (Ps) modification at the scissile phosphodiester (Pd) bond. Analysis of the stereochemical outcome of the net cleavage and rejoining reaction established that the reaction proceeds with retention of configuration, as expected for a double-displacement mechanism. Single-turnover kinetic studies on irreversible strand cleavage using 18/24 mer suicide substrates showed thio effects (k(Pd)/k(Ps)) of 340- and 30-fold for the Rp-Ps and Sp-Ps stereoisomers, respectively, but approximate to 10-fold smaller thio effects for the reverse single-turnover religation reaction (Rp-Ps = 30 and Sp-Ps = 3). As compared to the smaller suicide cleavage substrates, approach-to-equilibrium cleavage studies using 32/32 mer substrates showed 7-9 fold smaller thio effects on cleavage, similar effects on religation, and the same ratio of the Rp to Sp thio effect as the suicide cleavage reaction (approximate to 10). In general, thio effects of 2.4-7.2-fold on the cleavage equilibrium are observed for the wild-type and H265A enzymes, suggesting differences in the interactions of the enzyme with the nonbridging sulfur in the noncovalent and covalent complexes. Studies of the cleavage, religation, and approach-to-equilibrium reactions catalyzed by the H265A active site mutant revealed a stereoselective, Ii-fold decrease in the Rp-thio effect on cleavage and religation as compared to the wild-type enzyme. This result suggests that His-265 interacts with the nonbridging pro-Rp oxygen in the transition state for cleavage and religation, consistent with the arrangement of this conserved residue in the crystal structure of the human topoisomerase-DNA complex. In general, the greatest effect of thio substitution and the H265A mutation is to destabilize the transition state, with smaller effects on substrate binding. The interaction of His-265 with the pro-Rp nonbridging oxygen is inconsistent with the proposal that this conserved residue acts as a general acid in the strand cleavage reaction. C1 Univ Maryland, Ctr Adv Res Biotechnol, Rockville, MD 20850 USA. Natl Inst Stand & Technol, Rockville, MD 20850 USA. Polish Acad Sci, Ctr Mol & Macromol Studies, Dept Bioorgan Chem, Lodz, Poland. Sloan Kettering Inst, Program Mol Biol, New York, NY 10021 USA. RP Stivers, JT (reprint author), Univ Maryland, Ctr Adv Res Biotechnol, 9600 Gudelsky Dr, Rockville, MD 20850 USA. FU NIGMS NIH HHS [GM46330] NR 35 TC 51 Z9 51 U1 2 U2 8 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0006-2960 J9 BIOCHEMISTRY-US JI Biochemistry PD MAY 9 PY 2000 VL 39 IS 18 BP 5561 EP 5572 DI 10.1021/bi992429c PG 12 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 312PD UT WOS:000086950900040 PM 10820030 ER PT J AU Dizdaroglu, M Bauche, C Rodriguez, H Laval, J AF Dizdaroglu, M Bauche, C Rodriguez, H Laval, J TI Novel substrates of Escherichia coli Nth protein and its kinetics for excision of modified bases from DNA damaged by free radicals SO BIOCHEMISTRY LA English DT Article ID PERFORMANCE LIQUID-CHROMATOGRAPHY; GENERATED FREE-RADICALS; GAMMA-IRRADIATED DNA; ENDONUCLEASE-III; SACCHAROMYCES-CEREVISIAE; IONIZING-RADIATION; MASS-SPECTROMETRY; PURINE LESIONS; FPG PROTEIN; GLYCOSYLASE AB Escherichia coli Nth protein (endonuclease III) is a DNA glycosylase with a broad substrate specificity for pyrimidine derivatives. We discovered novel substrates of E. coli Nth protein using gas chromatography/isotope-dilution mass spectrometry and DNA samples, which were damaged by gamma-irradiation or by H2O2/Fe(III)-EDTA/ascorbic acid. These were 4,6-diamiao-5-formamidopyrimidine, 5,6-dihydroxyuracil, and 5,6-dihydroxycytosine. The first compound was recognized for the first time as a purine-derived substrate of the enzyme. We also investigated kinetics of excision of a multitude of modified bases from three damaged DNA substrates. Excision of modified bases was determined as a function of enzyme concentration, incubation time, and substrate concentration. Excision followed Michaelis-Menten kinetics. Kinetic parameters were determined for the following modified bases: 4,6-diamino-5-formamidopyrimidine, cis- and trans-thymine glycols, 5-hydroxycytosine, cis- and trans-uracil glycols, 5-hydroxyuracil, 5-hydroxy-5-methylhydantoin, alloxan, 5,6-dihydroxycytosine, 5,6-dihydroxyuracil, 5-hydroxy-6-hydrothymine, and 5-hydroxy-6-hydrouracil. The results show that three newly discovered substrates were excised by the enzyme with a preference similar to excision of its known major substrates such as thymine glycol and 5-hydroxycytosine. Excision kinetics significantly depended on the nature of the damaged DNA substrates in agreement with previous results on other DNA glycosylases. Specificity constants (k(cat)/K-M) of E. coli Nth protein were compared to those of its previously investigated functional homologues such as human and Schizosaccharomyces pombe Nth proteins and Saccharomyces cerevisiae Ntg1 and Ntg2 proteins. This comparison shows that significant differences exist with respect to substrate specificity and kinetic parameters despite extensive structural conservation among the Nth homologues. C1 Natl Inst Stand & Technol, Chem Sci & Technol Lab, Gaithersburg, MD 20899 USA. Inst Gustave Roussy, UMR 8532 CNRS, F-94805 Villejuif, France. RP Dizdaroglu, M (reprint author), Natl Inst Stand & Technol, Chem Sci & Technol Lab, Gaithersburg, MD 20899 USA. NR 43 TC 78 Z9 78 U1 0 U2 3 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0006-2960 J9 BIOCHEMISTRY-US JI Biochemistry PD MAY 9 PY 2000 VL 39 IS 18 BP 5586 EP 5592 DI 10.1021/bi9927787 PG 7 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 312PD UT WOS:000086950900042 PM 10820032 ER PT J AU Dagata, JA Perez-Murano, F Abadal, G Morimoto, K Inoue, T Itoh, J Yokoyama, H AF Dagata, JA Perez-Murano, F Abadal, G Morimoto, K Inoue, T Itoh, J Yokoyama, H TI Predictive model for scanned probe oxidation kinetics SO APPLIED PHYSICS LETTERS LA English DT Article ID ATOMIC-FORCE MICROSCOPE; FIELD-INDUCED OXIDATION; CONDUCTING-PROBE; SPACE-CHARGE; SILICON; FABRICATION AB Previous descriptions of scanned probe oxidation kinetics involved implicit assumptions that one-dimensional, steady-state models apply for arbitrary values of applied voltage and pulse duration. These assumptions have led to inconsistent interpretations regarding the fundamental processes that contribute to control of oxide growth rate. We propose a model that includes a temporal crossover of the system from transient to steady-state growth and a spatial crossover from predominantly vertical to coupled lateral growth. The model provides an excellent fit of available experimental data. (C) 2000 American Institute of Physics. [S0003-6951(00)03119-3]. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Univ Autonoma Barcelona, Dept Elect Engn, E-08193 Barcelona, Spain. Matsushita Elect Ind Co Ltd, Osaka, Japan. Electrotech Lab, Tsukuba, Ibaraki 305, Japan. RP Dagata, JA (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RI Perez-Murano, Francesc/A-6384-2013; Abadal, Gabriel/L-5655-2014 OI Perez-Murano, Francesc/0000-0002-4647-8558; NR 28 TC 99 Z9 99 U1 4 U2 11 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD MAY 8 PY 2000 VL 76 IS 19 BP 2710 EP 2712 DI 10.1063/1.126451 PG 3 WC Physics, Applied SC Physics GA 309QB UT WOS:000086778200022 ER PT J AU Munroe, TA Brito, A Hernandez, C AF Munroe, TA Brito, A Hernandez, C TI Symphurus insularis: A new eastern Atlantic dwarf tonguefish (Cynoglossidae : Pleuronectiformes) SO COPEIA LA English DT Article AB Symphurus insularis, a dwarf species of tonguefish reaching sizes to about 80 mm SL, is described based on 39 specimens collected in shallow-water habitats (3-23 m) at Madeira, the Canary Islands, and Sao Miguel, Azores, The new species is distinguished from its congeners by the combination of a 1-3-2 UD pattern, 12 caudal fin rays, 80-87 dorsal fin rays, 66-72 anal fin rays, 45-48 total vertebrae, 84-98 scales in a longitudinal series, unpigmented peritoneum, and ocular surface pigmentation featuring a yellowish to dark-brown background with a series of 3-8 mostly incomplete crossbands and usually 1-3 small, dark, spherical spots arranged in a longitudinal row along the body midline, together with a series of dark blotches alternating- with unpigmented areas on the dorsal and anal fins, and a spot and dark band on the caudal fin base with the distal four-fifths of the caudal fin unpigmented. Symphurus insularis most closely resembles S. reticulatus from St. Helena, S. rhytisma from the Caribbean Sea and northern Brazil, and S, lubbocki from Ascension Island. Symphurus insularis is the only species of dwarf tonguefish known from shallow-water habitats in the Macaronesian biogeographic subprovince of the eastern Atlantic. Pre vious reports of other species of symphurine tonguefishes from shallow-water habitats in these areas were based on misidentifications, A key to species of Symphurus occurring- in middle and eastern Atlantic waters is provided. C1 Natl Museum Nat Hist, Natl Marine Fisheries Serv, Systemat Lab, Washington, DC 20560 USA. Univ La Laguna, Fac Biol, Dept Biol Anim Ciencias Marinas, Tenerife 38206, Spain. RP Munroe, TA (reprint author), Natl Museum Nat Hist, Natl Marine Fisheries Serv, Systemat Lab, Washington, DC 20560 USA. EM munroe.thomas@nmnh.si.edu NR 27 TC 4 Z9 5 U1 0 U2 0 PU AMER SOC ICHTHYOLOGISTS & HERPETOLOGISTS PI MIAMI PA MAUREEN DONNELLY, SECRETARY FLORIDA INT UNIV BIOLOGICAL SCIENCES, 11200 SW 8TH STREET, MIAMI, FL 33199 USA SN 0045-8511 EI 1938-5110 J9 COPEIA JI Copeia PD MAY 8 PY 2000 IS 2 BP 491 EP 500 DI 10.1643/0045-8511(2000)000[0491:SIANEA]2.0.CO;2 PG 10 WC Zoology SC Zoology GA 314KU UT WOS:000087055600016 ER PT J AU Xu, GY Broholm, C Reich, DH Adams, MA AF Xu, GY Broholm, C Reich, DH Adams, MA TI Triplet waves in a quantum spin liquid SO PHYSICAL REVIEW LETTERS LA English DT Article ID SINGLET-GROUND-STATE; CHAIN; SR14CU24O41; EXCITATIONS; DYNAMICS; GAP AB We report a neutron scattering study of the spin-1/2 alternating bond antiferromagnet Cu(NO3)(2) 2.5D(2)O for 0.06 < k(B)T/J(1) < 1.5 For k(B)T/J(1) much less than 1 the excitation spectrum is dominated by a coherent singlet-triplet mode centered at J(1) = 0.442(2) meV with sinusoidal dispersion and a bandwidth of J(2) = 0.106(2) meV. A complete description of the zero temperature contribution to the scattering function from this mode is provided by the single mode approximation. At finite temperatures we observe exponentially activated band narrowing and damping. The relaxation rate is thermally activated and wave vector dependent with the periodicity of the reciprocal lattice. C1 Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. RAL, CCLRD, ISIS Facil, Didcot OX11 0QX, Oxon, England. Natl Inst Stand & Technol, Ctr Neutrol Res, Gaithersburg, MD 20899 USA. RP Xu, GY (reprint author), Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. RI Broholm, Collin/E-8228-2011; Xu, Guangyong/A-8707-2010 OI Broholm, Collin/0000-0002-1569-9892; Xu, Guangyong/0000-0003-1441-8275 NR 26 TC 69 Z9 69 U1 0 U2 4 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 MAY 8 PY 2000 VL 84 IS 19 BP 4465 EP 4468 DI 10.1103/PhysRevLett.84.4465 PG 4 WC Physics, Multidisciplinary SC Physics GA 312KC UT WOS:000086941600053 ER PT J AU Nizkorodov, SA Harper, WW Blackmon, BW Nesbitt, DJ AF Nizkorodov, SA Harper, WW Blackmon, BW Nesbitt, DJ TI Temperature dependent kinetics of the OH/HO2/O-3 chain reaction by time-resolved IR laser absorption spectroscopy SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID VIBRATIONAL-ENERGY DISTRIBUTION; OZONE UV SPECTROSCOPY; CROSS-SECTIONS; CHEMI-LUMINESCENCE; GROUND-STATE; EXCITED OH; NU-3 BAND; HO2; DYNAMICS; RELAXATION AB This paper presents an extensive temperature dependent kinetic study of the catalytic HOx ozone cycle, (1) OH + O-3 --> HO2 + O-2 and (2) HO2 + O-3 --> OH + 2 O-2, based on time-resolved, Doppler limited direct absorption spectroscopy of OH with a single mode (Delta nu = 0.0001 cm(-1)) high-resolution infrared laser. The sum of the two chain rate constants, k(1) + k(2), is measured over the 190-315 K temperature range and can be accurately described by an Arrhenius-type expression: k(1) + k(2) (cm(3)/s) = 2.26(40) x 10(-12) exp[-976(50)/T]. These results are in excellent agreement with studies by Ravishankara et al. [J. Chem. Phys. 1979, 70, 984] and Smith et al. [Int. J. Chem. Kinet. 1984, 16, 41] but are significantly higher than the values currently accepted for atmospheric modeling. In addition, these studies also reflect the first such rate measurements to access the 190-230 K temperature range relevant to kinetic modeling of stone chain loss in the lower stratosphere. C1 Natl Inst Stand & Technol, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. Univ Colorado, Dept Chem & Biochem, Boulder, CO 80309 USA. RP Nesbitt, DJ (reprint author), Natl Inst Stand & Technol, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. RI Nizkorodov, Sergey/I-4120-2014 OI Nizkorodov, Sergey/0000-0003-0891-0052 NR 42 TC 27 Z9 28 U1 0 U2 5 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 MAY 4 PY 2000 VL 104 IS 17 BP 3964 EP 3973 DI 10.1021/jp9934984 PG 10 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 311EY UT WOS:000086872800015 ER PT J AU Bentz, DP AF Bentz, DP TI Fibers, percolation, and spalling of high-performance concrete SO ACI MATERIALS JOURNAL LA English DT Article DE concrete; fibers; high-performance concrete; spalling; water-cement ratio ID CONDENSED SILICA FUME; INTERFACIAL ZONE; CEMENT PASTE; COMPUTER-SIMULATION; TRANSITION ZONE; MICROSTRUCTURE; AGGREGATE; HYDRATION; MORTAR AB While the strength and durability of high-performance concretes (HPCs) are often greatly superior to conventional concretes under ambient conditions, their failure is sometimes rapid and dramatic during exposure to a fire, characterized by the explosive spalling of layers from the exposed concrete surface. This failure mode is rarely encountered in conventional concretes of higher w/c ratios. In these concretes, it is suggested that the interfacial transition zones (ITZs) surrounding each aggregate particle provide a convenient escape route for the vapor built up during the thermal exposure. In HPC, these ITZ regions are thinner and not percolated, but can be repercolated by the addition of just a few (0.2 to 0.5% by volume) fibers. Here, simulations are conducted to determine the relative efficiency to different length fibers in creating a percolated network, and to investigate the effects of aggregate volume fraction and gradation on ITZ percolation. C1 Natl Inst Stand & Technol, Bldg Mat Div, Gaithersburg, MD 20899 USA. RP Bentz, DP (reprint author), Natl Inst Stand & Technol, Bldg Mat Div, Gaithersburg, MD 20899 USA. NR 52 TC 57 Z9 67 U1 1 U2 5 PU AMER CONCRETE INST PI FARMINGTON HILLS PA 38800 INTERNATIONAL WAY, COUNTRY CLUB DRIVE, PO BOX 9094, FARMINGTON HILLS, MI 48333-9094 USA SN 0889-325X J9 ACI MATER J JI ACI Mater. J. PD MAY-JUN PY 2000 VL 97 IS 3 BP 351 EP 359 PG 9 WC Construction & Building Technology; Materials Science, Multidisciplinary SC Construction & Building Technology; Materials Science GA 329TC UT WOS:000087923200012 ER PT J AU Ehara, K Mulholland, GW Hagwood, RC AF Ehara, K Mulholland, GW Hagwood, RC TI Determination of arbitrary moments of aerosol size distributions from measurements with a differential mobility analyzer SO AEROSOL SCIENCE AND TECHNOLOGY LA English DT Article ID LATEX-PARTICLES; DIAMETER; RANGE AB A method to determine arbitrary moments of aerosol size distributions from differential mobility analyzer measurements has been proposed. The proposed method is based on a modification of the algorithm developed by Knutson and Whitby to calculate the moments of electrical mobility distributions. For this modification, the electrical mobility and the charge distribution have been approximately expressed by power functions of the particle diameter. To evaluate the validity of the approximation, we have carried out numerical simulations for typical size distributions. We have found that for typical narrowly distributed aerosols such as polystyrene latex particles and particles that arise in the tandem differential mobility analyzer configuration, the distribution parameters can be accurately determined by this method. For a log-normally distributed aerosol, the accuracy of the distribution parameters determined by this method has been evaluated as a function of the geometric standard deviation. We have also compared the accuracy of the proposed method with other existing methods in the case of the asymmetric Gaussian distribution. C1 Natl Res Lab Metrol, Tsukuba, Ibaraki 3058563, Japan. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Ehara, K (reprint author), Natl Res Lab Metrol, 1-1-4 Umezono, Tsukuba, Ibaraki 3058563, Japan. NR 22 TC 13 Z9 13 U1 0 U2 4 PU TAYLOR & FRANCIS INC PI PHILADELPHIA PA 325 CHESTNUT ST, SUITE 800, PHILADELPHIA, PA 19106 USA SN 0278-6826 J9 AEROSOL SCI TECH JI Aerosol Sci. Technol. PD MAY PY 2000 VL 32 IS 5 BP 434 EP 452 DI 10.1080/027868200303560 PG 19 WC Engineering, Chemical; Engineering, Mechanical; Environmental Sciences; Meteorology & Atmospheric Sciences SC Engineering; Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA 307UJ UT WOS:000086672300004 ER PT J AU Doll, CNH Muller, JP Elvidge, CD AF Doll, CNH Muller, JP Elvidge, CD TI Night-time imagery as a tool for global mapping of socioeconomic parameters and greenhouse gas emissions SO AMBIO LA English DT Article ID HUMAN-SETTLEMENTS; CITY LIGHTS; LAND-USE; SATELLITE; POPULATION AB Night-time satellite imagery acquired between October 1994 and March 1995 is here exploited to derive economic and energy-related global maps. By considering the lit area of a city, and combining this with ancillary statistical information, an analysis was performed designed to investigate the potential of night-time imagery for quantitative estimation of global socioeconomic parameters. An attempt to estimate global urban population using correlations of lit area and urban populations to derive country-level relationships accounted for over 90% of the quoted total. Furthermore, the total lit area of a country has a statistically significant high correlation value with other parameters, specifically Gross Domestic Product (GDP) and total carbon dioxide (CO(2)) emission. The new technique is limited by the spatial resolution of the sensor and the poorer correlation using night-time lights for centrally-planned economies. These findings offer great potential for synoptic global mapping of such parameters in the future. C1 UCL, Dept Geomat Engn, London WC1E 6BT, England. NOAA, Natl Geophys Data Ctr, Solar Terr Phys Div, Boulder, CO 80303 USA. RP Doll, CNH (reprint author), UCL, Dept Geomat Engn, Gower St, London WC1E 6BT, England. EM cdoll@ge.ucl.ac.uk; jpmuller@ge.ucl.ac.uk; cde@ngdc.noaa.gov RI Elvidge, Christopher/C-3012-2009 NR 26 TC 129 Z9 140 U1 4 U2 33 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0044-7447 J9 AMBIO JI Ambio PD MAY PY 2000 VL 29 IS 3 BP 157 EP 162 DI 10.1639/0044-7447(2000)029[0157:NTIAAT]2.0.CO;2 PG 6 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA 325HP UT WOS:000087670400007 ER PT J AU Nelson, EJ Woicik, JC Hong, M Kwo, J Mannaerts, JP AF Nelson, EJ Woicik, JC Hong, M Kwo, J Mannaerts, JP TI Extended x-ray absorption fine-structure measurement of bond-length strain in epitaxial Gd2O3 on GaAs(001) SO APPLIED PHYSICS LETTERS LA English DT Article AB Extended x-ray absorption fine structure (EXAFS) has been used to measure the bond length in a 23 Angstrom epitaxial Gd2O3 film grown on GaAs(001). The Gd-O bond length is determined to be 2.390 +/- 0.013 Angstrom, which corresponds to a +0.063 +/- 0.013 Angstrom increase or a +2.7%+/- 0.6% bond-length strain relative to the bond length in a bulk Gd2O3 powder. Using a simple model for the strained film that matches the [001] and [-110] axes of Gd2O3 with the [110] and [1-10] axes of the GaAs(001) surface, the measured bond-length increase of the film determined by EXAFS agrees well with the perpendicular lattice distortion of the film determined by diffraction. (C) 2000 American Institute of Physics. [S0003-6951(00)00618-5]. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Lucent Technol, Bell Labs, Murray Hill, NJ 07974 USA. RP Nelson, EJ (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RI Hong, Minghwei/C-1433-2010 NR 7 TC 8 Z9 8 U1 0 U2 5 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD MAY 1 PY 2000 VL 76 IS 18 BP 2526 EP 2528 DI 10.1063/1.126397 PG 3 WC Physics, Applied SC Physics GA 307PY UT WOS:000086662900014 ER PT J AU Nagy, V AF Nagy, V TI Accuracy considerations in EPR dosimetry SO APPLIED RADIATION AND ISOTOPES LA English DT Article; Proceedings Paper CT International Conference on Biodosimetry CY JUN 22-26, 1998 CL RUSSIAN ACAD MED SCI, MED RADIOL RES CTR, MOSCOW, RUSSIA SP WHO, Int Atom Energy Agcy, European Commiss, US DOE, Chinese Acad Med Sci, Radiat Effects Res Fdn, Natl Res Ctr Environm & Hlth, German Fed Off Radiat Protect, German Res Ctr Air & Space, German Fed Minist Educ & Res, Int Bur, Bavarian State Minist Reg Dev & Environm Affairs, Russian Acad Sci, Russian Federat, State Comm Sci & Technol, Russian Acad Med Sci, Russian Federat, Minist Hlth, Russian Federat, Minist Atom Energy, Russian Assoc Radiol Problems, Govt Kaluga Oblast HO RUSSIAN ACAD MED SCI, MED RADIOL RES CTR ID CALIBRATION CURVE; REGRESSION; SIGNAL AB A brief overview of some of the potential sources of inaccuracies that are common to all kinds of electron paramagnetic resonance (EPR) dosimetry is given. The instrumental sources discussed are inaccuracies of receiver gain calibration, instability of the spectrometer sensitivity, and neglect of inhomogeneity of the fields in the resonators. The discussed sources of inaccuracies related to data processing are violations of basic assumptions of the used version of the least-squares technique, incorrect model selection for fitting the data, and nonoptimal design of the calibration experiment. Methods for detecting and correcting such inaccuracies are briefly discussed and references to the original literature are given. (C) 2000 Elsevier Science Ltd, All rights reserved. C1 Natl Inst Stand & Technol, Ionizing Radiat Div, Gaithersburg, MD 20899 USA. RP Nagy, V (reprint author), Natl Inst Stand & Technol, Ionizing Radiat Div, 100 Bur Dr,Stop 8460, Gaithersburg, MD 20899 USA. NR 28 TC 57 Z9 58 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0969-8043 J9 APPL RADIAT ISOTOPES JI Appl. Radiat. Isot. PD MAY PY 2000 VL 52 IS 5 BP 1039 EP 1050 DI 10.1016/S0969-8043(00)00052-X PG 12 WC Chemistry, Inorganic & Nuclear; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging SC Chemistry; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging GA 312QJ UT WOS:000086953700005 ER PT J AU Romanyukha, AA Desrosiers, MF Regulla, DF AF Romanyukha, AA Desrosiers, MF Regulla, DF TI Current issues on EPR dose reconstruction in tooth enamel SO APPLIED RADIATION AND ISOTOPES LA English DT Article; Proceedings Paper CT International Conference on Biodosimetry CY JUN 22-26, 1998 CL RUSSIAN ACAD MED SCI, MED RADIOL RES CTR, MOSCOW, RUSSIA SP WHO, Int Atom Energy Agcy, European Commiss, US DOE, Chinese Acad Med Sci, Radiat Effects Res Fdn, Natl Res Ctr Environm & Hlth, German Fed Off Radiat Protect, German Res Ctr Air & Space, German Fed Minist Educ & Res, Int Bur, Bavarian State Minist Reg Dev & Environm Affairs, Russian Acad Sci, Russian Federat, State Comm Sci & Technol, Russian Acad Med Sci, Russian Federat, Minist Hlth, Russian Federat, Minist Atom Energy, Russian Assoc Radiol Problems, Govt Kaluga Oblast HO RUSSIAN ACAD MED SCI, MED RADIOL RES CTR ID ELECTRON-SPIN-RESONANCE; RADIATION-DOSIMETRY; ESR DOSIMETRY; GAMMA-RAYS; X-RAYS; BONE; ION; BIODOSIMETRY; CARBONATE; SPECTRUM AB This paper focuses on the opportunities to gain risk assessment information from populations exposed to ionizing radiation. Details are presented on the scale of the nuclear events in several areas within the former Soviet Union. An overview of the issues associated with dose reconstruction by electron paramagnetic resonance (EPR) is given. Principles and outline of the EPR tooth enamel dose assessment are described. Technical details, the latest achievements and the problems of each procedural step are analyzed. In addition, the present accuracy of the EPR dose reconstruction, its problems and cost are discussed. (C) 2000 Elsevier Science Ltd. All rights reserved. C1 GSF Forschungszentrum Umwelt & Gesundheit, Inst Radiat Protect, D-85764 Neuherberg, Germany. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Regulla, DF (reprint author), GSF Forschungszentrum Umwelt & Gesundheit, Inst Radiat Protect, D-85764 Neuherberg, Germany. NR 47 TC 24 Z9 24 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0969-8043 J9 APPL RADIAT ISOTOPES JI Appl. Radiat. Isot. PD MAY PY 2000 VL 52 IS 5 BP 1265 EP 1273 DI 10.1016/S0969-8043(00)00082-8 PG 9 WC Chemistry, Inorganic & Nuclear; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging SC Chemistry; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging GA 312QJ UT WOS:000086953700042 PM 10836441 ER PT J AU Bugay, A Kolesnik, S Mehta, K Nagy, V Desrosiers, M AF Bugay, A Kolesnik, S Mehta, K Nagy, V Desrosiers, M TI Temperature stabilization of alanine dosimeters used for food processing and sterilization SO APPLIED RADIATION AND ISOTOPES LA English DT Article; Proceedings Paper CT International Conference on Biodosimetry CY JUN 22-26, 1998 CL RUSSIAN ACAD MED SCI, MED RADIOL RES CTR, MOSCOW, RUSSIA SP WHO, Int Atom Energy Agcy, European Commiss, US DOE, Chinese Acad Med Sci, Radiat Effects Res Fdn, Natl Res Ctr Environm & Hlth, German Fed Off Radiat Protect, German Res Ctr Air & Space, German Fed Minist Educ & Res, Int Bur, Bavarian State Minist Reg Dev & Environm Affairs, Russian Acad Sci, Russian Federat, State Comm Sci & Technol, Russian Acad Med Sci, Russian Federat, Minist Hlth, Russian Federat, Minist Atom Energy, Russian Assoc Radiol Problems, Govt Kaluga Oblast HO RUSSIAN ACAD MED SCI, MED RADIOL RES CTR AB The International Atomic Energy Agency has established a dose quality audit service for radiation processing facilities. The objective of the service is to provide an independent check on the routine dosimetry system in use at the facility. The audit service is based on the use of alanine EPR dosimetry. Generally, alanine dosimeters are irradiated at the facility together with a product, and the response is then analyzed at the IAEA laboratory. Practice of the audit service has shown that the main uncertainty in alanine dosimetry is due to absence of temperature control at the irradiation facilities. Were, a method for stabilizing the temperature of the dosimeter during irradiation is proposed. (C) 2000 Elsevier Science Ltd. Ail rights reserved. C1 Inst Semicond Phys, UA-252650 Kiev, Ukraine. Int Atom Energy Agcy, Dosimetry & Med Radiat Phys Sect, A-1400 Vienna, Austria. NIST, Ionizing Radiat Div, Gaithersburg, MD 20899 USA. RP Bugay, A (reprint author), Inst Semicond Phys, UA-252650 Kiev, Ukraine. NR 1 TC 4 Z9 4 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0969-8043 J9 APPL RADIAT ISOTOPES JI Appl. Radiat. Isot. PD MAY PY 2000 VL 52 IS 5 BP 1371 EP 1373 DI 10.1016/S0969-8043(00)00097-X PG 3 WC Chemistry, Inorganic & Nuclear; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging SC Chemistry; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging GA 312QJ UT WOS:000086953700057 ER PT J AU Morimoto, K Perez-Murano, F Dagata, JA AF Morimoto, K Perez-Murano, F Dagata, JA TI Density variations in scanned probe oxidation SO APPLIED SURFACE SCIENCE LA English DT Article DE silicon nanofabrication; field-enhanced oxidation; scanned probe microscopy; transmission electron microscopy ID ATOMIC-FORCE MICROSCOPE; FIELD-INDUCED OXIDATION; DRY OXIDATION; SPACE-CHARGE; SILICON; FABRICATION; KINETICS; GROWTH AB Total oxide thickness and molar volume ratio for scanned probe microscopy (SPM) oxide nanostructures are obtained for a wide range of silicon substrates and exposure conditions by high-resolution cross-sectional transmission electron microscopy (HR XTEM) and atomic force microscopy (AFM). Oxide density is shown to be a function of substrate doping and voltage pulse parameters. Dislocations produced by the SPM voltage pulse within the silicon substrate are reported from direct XTEM observation for the first time. These dislocations are completely annealed out at 600 degrees C. The dimensional response of SPM oxides to annealing and/or mechanical stress imposed by metal deposition are found to be negligible for n-type substrates, but SPM oxide films on p-type substrates are strongly compressed or expanded. This behavior is attributed to the formation of positively charged defects and ionic/electronic recombination near the growing Si/SiOx interface. Implications of these results for use of SPM oxide in silicon nanodevice processing are discussed. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Matsushita Elect Ind Co Ltd, Adv Technol Res Lab, Moriguchi, Osaka 5708501, Japan. Univ Autonoma Barcelona, Dept Elect Engn, E-08193 Bellaterra, Spain. RP Dagata, JA (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RI Perez-Murano, Francesc/A-6384-2013 OI Perez-Murano, Francesc/0000-0002-4647-8558 NR 23 TC 45 Z9 46 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0169-4332 J9 APPL SURF SCI JI Appl. Surf. Sci. PD MAY PY 2000 VL 158 IS 3-4 BP 205 EP 216 DI 10.1016/S0169-4332(00)00017-9 PG 12 WC Chemistry, Physical; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Chemistry; Materials Science; Physics GA 330KT UT WOS:000087961800004 ER PT J AU Johnson, KE Conti, PS AF Johnson, KE Conti, PS TI Recent star formation in several galaxies of the tidally disturbed system HCG 31 SO ASTRONOMICAL JOURNAL LA English DT Article DE galaxies : interactions; galaxies : starburst; galaxies : star clusters ID WOLF-RAYET GALAXIES; COMPACT-GROUPS; LUMINOSITY FUNCTION; MERGER REMNANTS; DWARF GALAXIES; PROGENITORS; EVOLUTION; CLUSTERS; ANTENNAE; DISK AB High-resolution (0." 7 to 0." 8) H alpha images of the Hickson Compact Group 31 (HCG 31) obtained with the WIYN telescope are used in conjunction with broadband optical images from the Hubble Space Telescope (HST) to examine the star formation history and properties of the component galaxies. The high spatial resolution of the WIYN telescope has allowed us to identify a large number of starburst regions from their H alpha emission, which traces the recent star birth activity. The HST images of galaxies E and F reveal more detail within the starburst regions in which we have identified numerous super star clusters (SSCs). Photometry of these starburst regions and SSCs in the H alpha and optical images indicates that there has been a substantial amount of star formation throughout HGC 31 over the past 10 Myr. The H alpha equivalent widths suggest activity within the group as recently as a few megayears ago. There is evidence that galaxy F, the youngest member of the group, is possibly undergoing its initial episode of star formation, as no underlying stellar population has yet been detected. C1 Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. Natl Inst Stand & Technol, Boulder, CO 80309 USA. Univ Colorado, Dept Astrophys & Planetary Sci, Boulder, CO 80309 USA. RP Johnson, KE (reprint author), Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. NR 40 TC 22 Z9 22 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 MAY PY 2000 VL 119 IS 5 BP 2146 EP 2153 DI 10.1086/301361 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 318YB UT WOS:000087311300011 ER PT J AU Chen, P Pearson, JC Pickett, HM Matsuura, S Blake, GA AF Chen, P Pearson, JC Pickett, HM Matsuura, S Blake, GA TI Submillimeter-wave measurements and analysis of the ground and v(2)=1 states of water SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article DE infrared : ISM : lines and bands; ISM : molecules; methods : laboratory; molecular data ID POTENTIAL-ENERGY SURFACE; PADE HAMILTONIAN OPERATOR; HIGH-RESOLUTION SPECTRUM; DIPOLE-MOMENT FUNCTION; ROTATIONAL LEVELS; LINE POSITIONS; TRIATOMIC-MOLECULES; BAND INTENSITIES; FTS MEASUREMENTS; H2O AB In order to facilitate further studies of water in the interstellar medium, the envelopes of late-type stars, jets, and shocked regions, the frequencies of 17 newly measured H-2 O-16 transitions between 0.841 and 1.575 THz are reported. A complete update of the available water line frequencies and a detailed calculation of unmeasured rotational transitions and transition intensities as a function of temperature are presented for the ground and nu(2) = 1 state levels below 3000 cm(-1) of excitation energy. The new terahertz transitions were measured with a recently developed laser difference frequency spectrometer. Six of these transitions arise from the nu(2) = 1 state, and the other 11 are in the ground state; all have lower state energies from 700 to 1750 cm(-1) and should be accessible to Stratospheric Observatory For Infrared Astronomy (SOFIA) through the atmosphere. The transitions near 0.850 THz are accessible from the ground with existing receivers. Observations of the newly measured nu(2) = 1 state transitions, which include the 1(1.1)-0(0.0) fundamental at 1.2057 THz and five other very low J transitions, should provide valuable insights into role played by the nu(2) = 1 state in the cooling dynamics of jets, shocks, masers, and strongly infrared-pumped regions. The line list is presented to assist in the planning of observational campaigns with the Far-infrared Space Telescope (FIRST) and other proposed space missions with which a full suite of water observations can be carried out. C1 Natl Inst Stand & Technol, Div Time & Frequency, Boulder, CO 80303 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. CALTECH, Div Geol & Planetary Sci, Pasadena, CA 91125 USA. RP Chen, P (reprint author), Natl Inst Stand & Technol, Div Time & Frequency, Mail Stop 847-10,325 Broadway, Boulder, CO 80303 USA. RI Chen, Pin/B-1112-2008; Matsuura, Shuji/B-5658-2016 OI Chen, Pin/0000-0003-1195-9666; Matsuura, Shuji/0000-0002-5698-9634 NR 48 TC 28 Z9 28 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 5720 SOUTH WOODLAWN AVE, CHICAGO, IL 60637-1603 USA SN 0067-0049 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD MAY PY 2000 VL 128 IS 1 BP 371 EP 385 DI 10.1086/313377 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 344FV UT WOS:000088749300014 ER PT J AU Planas, JV Athos, J Goetz, FW Swanson, P AF Planas, JV Athos, J Goetz, FW Swanson, P TI Regulation of ovarian steroidogenesis in vitro by follicle-stimulating hormone and luteinizing hormone during sexual maturation in salmonid fish SO BIOLOGY OF REPRODUCTION LA English DT Article ID TROUT SALVELINUS-FONTINALIS; GONADOTROPINS GTH-I; PERCH PERCA-FLAVESCENS; COHO SALMON; ONCORHYNCHUS-RHODURUS; REPRODUCTIVE-CYCLE; STEROID-PRODUCTION; FINAL MATURATION; GENE-EXPRESSION; GRANULOSA-CELLS AB The regulation of ovarian steroidogenesis in vitro by coho salmon FSH and LH was investigated in intact coho salmon follicles and isolated follicular layers at various stages of oocyte maturation, from late vitellogenesis until the completion of germinal vesicle breakdown (GVBD). In granulosa layers from all stages, LH, but not FSH, stimulated 17 alpha,20 beta-dihydroxy-4-pregnen-3-one (17,20 beta-P) production. In theca-interstitial layers from all stages, FSH and LH stimulated steroid production, LH being more potent than FSH. The basal steroid output of intact follicles was significantly lower than that of isolated follicular layers, and their response to FSH and LH also differed. First, the intact follicles produced 17 alpha-hydroxyprogesterone in response to FSH during the central germinal vesicle stage while theca-interstitial layers did not. Second, estradiol-17 beta production was not inhibited by LH during final oocyte maturation in intact follicles, as observed for granulosa layers. Our results indicate that LH is the determining factor regulating the production of the maturation-inducing steroid, 17,20 beta-P, and the induction of GVBD in the salmonid ovary. In summary, we have provided evidence for maturation-associated changes in the effects of FSH and LH in the salmonid ovary, which further supports the hypothesis that FSH and LH have distinct functions in the teleost ovary. C1 Univ Washington, Sch Fisheries, Seattle, WA 98195 USA. NOAA, Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, Seattle, WA 98112 USA. Univ Notre Dame, Dept Biol Sci, Notre Dame, IN 46556 USA. RP Planas, JV (reprint author), Univ Barcelona, Fac Biol, Dept Fisiol, Av Diagnonal 645, Barcelona 08028, Spain. NR 41 TC 75 Z9 80 U1 1 U2 21 PU SOC STUDY REPRODUCTION PI MADISON PA 1603 MONROE ST, MADISON, WI 53711-2021 USA SN 0006-3363 J9 BIOL REPROD JI Biol. Reprod. PD MAY PY 2000 VL 62 IS 5 BP 1262 EP 1269 DI 10.1095/biolreprod62.5.1262 PG 8 WC Reproductive Biology SC Reproductive Biology GA 307XL UT WOS:000086679400021 PM 10775175 ER PT J AU Rosenberg, A Bigford, TE Leathery, S Hill, RL Bickers, K AF Rosenberg, A Bigford, TE Leathery, S Hill, RL Bickers, K TI Ecosystem approaches to fishery management through essential fish habitat SO BULLETIN OF MARINE SCIENCE LA English DT Article; Proceedings Paper CT 2nd William R and Lenore Mote International Symposium in Fisheries Ecology CY NOV 04-06, 1998 CL SARASOTA, FLORIDA SP Environm Defense Fund, Ctr Marine Conservat, Amer Fisheries Soc, Marine Fisheries Sect AB The Magnuson-Stevens Fishery Conservation and Management Act recognizes that fish stocks depend on healthy ecosystems and requires that fishery managers expand their management regimes to include the very basis of healthy fisheries-the habitat itself. The 1996 amendments to this primary United States marine fishery-management law include a new mandate to identify habitats essential to managed living marine resources and to take steps to ensure that those habitats remain healthy and can support sustainable fisheries. Until now, the legislative mandate for protecting habitat for marine and anadromous stocks came through statutes not specifically focused on the needs of commercial and recreational fish species. Now, there is explicit linkage between fishery-management programs, traditionally designed to manage the harvesting activity itself, and efforts to ensure that fishing and nonfishing activities do not undermine the productivity of the stocks. This emphasis on habitat health and productivity brings a broader ecosystem perspective to traditional fishery management. The insertion of essential fish habitat (EFH) provisions into fisheries management has been an enormous undertaking. The agency and the regional fishery management councils, working with other partners, completed the first stage of the process within very tight statutory deadlines. The councils have made use of all of the tools provided them under the act and the EFH regulations, such as designating habitat areas of particular concern (EFH-HAPCs), recommending fishing restrictions within special areas, defining priority research and information needs, and documenting threats and conservation measures appropriate for federal actions that may adversely affect EFH. This effort has entailed a great deal of scientific as well as policy analysis. We are currently implementing the federal consultation process to address threats to fish habitat in a consistent and timely manner. This new habitat thrust will align fishery managers and scientists with new allies in the habitat arena, increasing benefits to marine resource-management programs and fishery management. As suggested by the theme of this issue, an understanding and consideration of marine reserves and other special-area management concepts can benefit federal fishery management. This article gives an overview of how the fishery-management councils are fulfilling the essential fish habitat mandate by using a broader ecosystem approach to conservation that considers the ecological role of managed species, analyzes species' habitat needs from state waters to the high seas, and examines shifts in population health and sustainability over the course of decades. C1 NOAA, Natl Marine Fisheries Serv, Silver Spring, MD 20910 USA. RP Rosenberg, A (reprint author), NOAA, Natl Marine Fisheries Serv, 1315 E West Highway,SSMC3-F, Silver Spring, MD 20910 USA. NR 6 TC 57 Z9 64 U1 1 U2 22 PU ROSENSTIEL SCH MAR ATMOS SCI PI MIAMI PA 4600 RICKENBACKER CAUSEWAY, MIAMI, FL 33149 USA SN 0007-4977 J9 B MAR SCI JI Bull. Mar. Sci. PD MAY PY 2000 VL 66 IS 3 BP 535 EP 542 PG 8 WC Marine & Freshwater Biology; Oceanography SC Marine & Freshwater Biology; Oceanography GA 346WP UT WOS:000088894300003 ER PT J AU Koenig, CC Coleman, FC Grimes, CB Fitzhugh, GR Scanlon, KM Gledhill, CT Grace, M AF Koenig, CC Coleman, FC Grimes, CB Fitzhugh, GR Scanlon, KM Gledhill, CT Grace, M TI Protection of fish spawning habitat for the conservation of warm-temperate reef-fish fisheries of shelf-edge reefs of Florida SO BULLETIN OF MARINE SCIENCE LA English DT Article; Proceedings Paper CT 2nd William R and Lenore Mote International Symposium in Fisheries Ecology CY NOV 04-06, 1998 CL SARASOTA, FLORIDA SP Environm Defense Fund, Ctr Marine Conservat, Amer Fisheries Soc, Marine Fisheries Sect ID SOUTHEASTERN UNITED-STATES; MYCTEROPERCA-MICROLEPIS; CONTINENTAL-SHELF; OCULINA-VARICOSA; CORAL-REEFS; ATLANTIC; GULF; CONSEQUENCES; AGGREGATIONS; DISTURBANCE AB We mapped and briefly describe the surficial geology of selected examples of shelf-edge reefs (50 - 120 m deep) of the southeastern United States, which are apparently derived from ancient Pleistocene shorelines and are intermittently distributed throughout the region. These reefs are ecologically significant because they support a diverse array of fish and invertebrate species, and they are the only aggregation spawning sites of gag (Mycteroperca microlepis), scamp (M. phenax), and other economically important reef fish. Our studies on the east Florida shelf in the Experimental Oculina Research Reserve show that extensive damage to the habitat-structuring coral Oculina varicosa has occurred in the past, apparently from trawling and dredging activities of the 1970s and later. On damaged or destroyed Oculina habitat, reef-fish abundance and diversity are low, whereas on intact habitat, reef-fish diversity is relatively high compared to historical diversity on the same site. The abundance and biomass of the economically important reef fish was much higher in the past than it is now, and spawning aggregations of gag and scamp have been lost or greatly reduced in size. On the west Florida shelf, fishers have concentrated on shelf-edge habitats for over 100 yrs, but fishing intensity increased dramatically in the 1980s. Those reefs are characterized by low abundance of economically important species. The degree and extent of habitat damage there is unknown. We recommend marine fishery reserves to protect habitat and for use in experimentally examining the potential production of unfished communities. C1 Florida State Univ, Dept Biol Sci, Inst Fishery Resource Ecol, Tallahassee, FL 32306 USA. Natl Marine Fisheries Serv, Tiburon Lab, Tiburon, CA 94920 USA. Natl Marine Fisheries Serv, Panama City Lab, Panama City, FL 32408 USA. US Geol Survey, Woods Hole, MA 02543 USA. Natl Marine Fisheries Serv, Pascagoula Lab, Pascagoula, MS 39563 USA. RP Koenig, CC (reprint author), Florida State Univ, Dept Biol Sci, Inst Fishery Resource Ecol, B-157, Tallahassee, FL 32306 USA. NR 78 TC 93 Z9 97 U1 2 U2 7 PU ROSENSTIEL SCH MAR ATMOS SCI PI MIAMI PA 4600 RICKENBACKER CAUSEWAY, MIAMI, FL 33149 USA SN 0007-4977 J9 B MAR SCI JI Bull. Mar. Sci. PD MAY PY 2000 VL 66 IS 3 BP 593 EP 616 PG 24 WC Marine & Freshwater Biology; Oceanography SC Marine & Freshwater Biology; Oceanography GA 346WP UT WOS:000088894300007 ER PT J AU Bohnsack, JA AF Bohnsack, JA TI A comparison of the short-term impacts of no-take marine reserves and minimum size limits SO BULLETIN OF MARINE SCIENCE LA English DT Article; Proceedings Paper CT 2nd William R and Lenore Mote International Symposium in Fisheries Ecology CY NOV 04-06, 1998 CL SARASOTA, FLORIDA SP Environm Defense Fund, Ctr Marine Conservat, Amer Fisheries Soc, Marine Fisheries Sect ID FISHERIES MANAGEMENT; CONSERVATION; PATTERNS; FLORIDA AB Establishing no-take marine reserves (NTRs) displaces fishing effort to surrounding areas, creating concerns about short-term impacts on resources and fishers before longterm benefits can accrue. Models were developed to compare the effects of short-term displacement caused by of NTRs to effects of minimum size limits (MSLs), one of the most widely applied management measures in the southeastern U.S. Projected impacts on resource protection and fishers were assessed on the basis of the portion of a population either protected or legally available to fishing. Tn all cases, existing MSLs had greater impact on total numbers of fish landed (reduced by 38 to 70%) than on the weight of total landings (reduced by 14 to 26%). NTRs protected sedentary species in approximate proportion to the total habitat closed to fishing but provided less protection as species mobility increased. These differences in protection due to mobility were greater for reserves covering small percentages of total habitat. Predicted short-term displacement impacts on fishers were low for reserves covering small percentages of the total habitat, but they increased exponentially as the percentage of total habitat closed increased. Displacement impacts were predicted to be highest for fishers pursuing sedentary species and decreased for more mobile species. Detrimental impacts to surrounding habitat from displacement depended on initial fishery conditions, gear type, and the total proportion of habitat closed. Although more fishers are affected by the no-take rule, concerns about short-term displacement impacts appear to be exaggerated. Some: opposition to establishing NTRs may result in part because the no-take provision is more difficult to circumvent than other regulations. When combined with traditional management tools, no-take reserves offer increased flexibility for supporting fisheries and protecting resources. C1 NOAA, SE Fisheries Sci Ctr, Natl Marine Fisheries Serv, Miami, FL 33149 USA. RP Bohnsack, JA (reprint author), NOAA, SE Fisheries Sci Ctr, Natl Marine Fisheries Serv, 75 Virginia Beach Dr, Miami, FL 33149 USA. NR 45 TC 28 Z9 30 U1 0 U2 7 PU ROSENSTIEL SCH MAR ATMOS SCI PI MIAMI PA 4600 RICKENBACKER CAUSEWAY, MIAMI, FL 33149 USA SN 0007-4977 J9 B MAR SCI JI Bull. Mar. Sci. PD MAY PY 2000 VL 66 IS 3 BP 635 EP 650 PG 16 WC Marine & Freshwater Biology; Oceanography SC Marine & Freshwater Biology; Oceanography GA 346WP UT WOS:000088894300009 ER PT J AU Eklund, AM McClellan, DB Harper, DE AF Eklund, AM McClellan, DB Harper, DE TI Black grouper aggregations in relation to protected areas within the Florida Keys National Marine Sanctuary SO BULLETIN OF MARINE SCIENCE LA English DT Article; Proceedings Paper CT 2nd William R and Lenore Mote International Symposium in Fisheries Ecology CY NOV 04-06, 1998 CL SARASOTA, FLORIDA SP Environm Defense Fund, Ctr Marine Conservat, Amer Fisheries Soc, Marine Fisheries Sect ID FISH SPAWNING AGGREGATIONS; MANAGEMENT; FISHERIES; RESERVES AB During the winter of 1997-1998, we discovered an aggregation of black grouper, Mycteroperca bonaci, less than 100 m outside a newly designated marine reserve. The spawning mode and aggregation behavior of black grouper have not been reported previously, even though this species is an important component of both the recreational and commercial fishing sectors of the Florida Keys. The grouper aggregation included up to 96 individuals just seaward of a no-take area within the Florida Keys National Marine Sanctuary. We documented the seasonal and spatial distribution of the aggregation during a series of drift dives over the presumed spawning area. In January and February of 1998, the black grouper were aggregated in a spatially discrete 100-m(2) area in 18-28 m of water. By April the number had declined, and their distribution had become more even, rather than aggregated. Although the marine reserve offers total protection from all fishing activity, these groupers were susceptible to being caught in large numbers, as the entire aggregation remained in waters deeper than the reserve boundary. If the reserve boundary were moved seaward beyond the slope-sand interface along the 30-m contour, the vulnerable aggregation would be protected. C1 SW Fisheries Sci Ctr, Natl Marine Fisheries Serv, Miami, FL 33149 USA. RP Eklund, AM (reprint author), SW Fisheries Sci Ctr, Natl Marine Fisheries Serv, 75 Virginia Beach Dr, Miami, FL 33149 USA. NR 21 TC 27 Z9 28 U1 0 U2 12 PU ROSENSTIEL SCH MAR ATMOS SCI PI MIAMI PA 4600 RICKENBACKER CAUSEWAY, MIAMI, FL 33149 USA SN 0007-4977 J9 B MAR SCI JI Bull. Mar. Sci. PD MAY PY 2000 VL 66 IS 3 BP 721 EP 728 PG 8 WC Marine & Freshwater Biology; Oceanography SC Marine & Freshwater Biology; Oceanography GA 346WP UT WOS:000088894300015 ER PT J AU Murawski, SA Brown, R Lai, HL Rago, PJ Hendrickson, L AF Murawski, SA Brown, R Lai, HL Rago, PJ Hendrickson, L TI Large-scale closed areas as a fishery-management tool in temperate marine systems: The Georges Bank experience SO BULLETIN OF MARINE SCIENCE LA English DT Article; Proceedings Paper CT 2nd William R and Lenore Mote International Symposium in Fisheries Ecology CY NOV 04-06, 1998 CL SARASOTA, FLORIDA SP Environm Defense Fund, Ctr Marine Conservat, Amer Fisheries Soc, Marine Fisheries Sect ID RESERVES; CONSERVATION AB Seasonal closed areas have been an element of fishery management in New England waters since 1970 but before 1994 had limited impact on the conservation of groundfish stocks for which they were de:signed. Beginning in December of 1994, three large areas of historic importance to groundfish spawning and juvenile production on Georges Bank and in Southern New England, totaling 17,000 km(2), were closed year-round to any gears capable of retaining groundfish (trawls, scallop dredges, gill nets, hook fishing). In the ensuing five years, the closed areas contributed significantly to reduced fishing mortality of depicted groundfish stocks. Placements of the closed areas afforded the greatest year-round protection to the shallow-sedentary assemblage of fishes (primarily flounders, skates, and miscellaneous others) and bivalve molluscs, Although the closures afforded less year-round protection to migratory age groups of Atlantic cod, Gadus morhua, and haddock, Melanogrammus aeglefinus, additional new regulations in open areas and in the Canadian portions of Georges Bank also contributed to the observed reductions in stock-wide fishing mortality rates. The areas were closed to dredge gear designed for sea scallops, Placopecten magellanicus, because of groundfish by-catch (particularly of flounders). Scallop biomass increased 14-fold within the closed areas during 1994-1998. In July 1998, total and harvestable scallop biomasses were 9 and 14 times denser, respectively, in closed than in adjacent open areas. A portion of the closed areas was designated a "habitat area of particular concern" on the basis of patterns of occurrence of juvenile groundfish in gravel/cobble sediment types. Managers reopened portions of one closed area to sea-scallop dredging in 1999, but restrictions on gear and areas fished were used to minimize groundfish by-catch and impact on juvenile cod and haddock on gravel substrates. Results from these reopenings have encouraged managers to contemplate a formal 'area rotation' scheme for scallops intended to improve yield per recruit. Closures of large portions of Georges Bank have proved to be an important element leading to more effective conservation of numerous resource and nonresource species, despite selection of the closed areas on the basis of seasonal spawning grounds of haddock and the distribution of yellowtail flounder, Limanda ferrugineus, in southern New England. In the future, factors other than fishing mortality reduction, including optimal placement to enhance larval production and to protect nursery areas and spawning concentrations, may well influence the selection of closed-area boundaries. C1 NE Fisheries Sci Ctr, Natl Marine Fisheries Serv, Woods Hole, MA 02543 USA. RP Murawski, SA (reprint author), NE Fisheries Sci Ctr, Natl Marine Fisheries Serv, Woods Hole, MA 02543 USA. NR 28 TC 222 Z9 225 U1 10 U2 65 PU ROSENSTIEL SCH MAR ATMOS SCI PI MIAMI PA 4600 RICKENBACKER CAUSEWAY, MIAMI, FL 33149 USA SN 0007-4977 J9 B MAR SCI JI Bull. Mar. Sci. PD MAY PY 2000 VL 66 IS 3 BP 775 EP 798 PG 24 WC Marine & Freshwater Biology; Oceanography SC Marine & Freshwater Biology; Oceanography GA 346WP UT WOS:000088894300019 ER PT J AU McAdie, CJ Lawrence, MB AF McAdie, CJ Lawrence, MB TI Improvements in tropical cyclone track forecasting in the Atlantic basin, 1970-98 SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article ID PREDICTION; SYSTEM AB Tropical cyclone track forecasts issued by the Tropical Prediction Center/National Hurricane Center for the Atlantic basin have improved over the period 1970-98. Improvement is shown at 24, 48, and 72 h. Although this improve ment can be shown without any preconditioning of the data, the question of accounting for forecast difficulty is addressed, building upon the work of Neumann. A decrease in the initial position errors over the same period is also shown. Track forecast errors generated by the Atlantic climatology and persistence (CLIPER) model (run in "best-track" mode) are used as a measure of forecast difficulty. Using the annual average CLIPER errors in a regression against the official forecast errors yields an equation giving an expected error for each year under consideration. The expected error (representing forecast difficulty) is then subtracted from the observed official errors. The resulting set of differences can then be examined for long-term trends, difficulty having been accounted for. Fitting a straight line to these differences (1970-98) yields the result that official forecast errors have decreased by an average of 1.0% per year at 24 h, by 1.7% per year at 48 h, and by 1.9% per year at 72 h. A second-order fit, however, suggests that the rate of improvement has increased during the latter half of the period. C1 NOAA, Trop Predict Ctr, NCEP, NWS,Natl Hurricane Ctr, Miami, FL 33165 USA. RP McAdie, CJ (reprint author), NOAA, Trop Predict Ctr, NCEP, NWS,Natl Hurricane Ctr, 11691 SW 17th St, Miami, FL 33165 USA. NR 23 TC 49 Z9 51 U1 0 U2 3 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 MAY PY 2000 VL 81 IS 5 BP 989 EP 997 DI 10.1175/1520-0477(2000)081<0989:IITCTF>2.3.CO;2 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 306FY UT WOS:000086587700001 ER PT J AU Molenar, DA Schrab, KJ Purdom, JFW AF Molenar, DA Schrab, KJ Purdom, JFW TI RAMSDIS contributions to NOAA satellite data utilization SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article AB The Regional and Mesoscale Meteorology (RAMM) Advanced Meteorological Satellite Demonstration and Interpretation System (RAMSDIS) was developed as part of an effort to get high quality digital satellite data to field forecasters prior to the deployment of the satellite component of the National Weather Service (NWS) Modernization Program. RAMSDIS was created by the National Oceanic and Atmospheric Administration (NOAA) National Environmental Satellite, Data and Information Service RAMM Team. RAMSDIS has made significant contributions to NOAA's satellite training and technology transfer program. The project has had a major impact on the utilization of digital satellite data, both nationally and internationally, providing the sole source for high-resolution digital satellite data at some NWS Forecast Offices (FOs) since 1993. In addition to its use in the FO, RAMSDIS has also provided data distribution and research capabilities on a common platform to several NOAA laboratories, allowing for more efficient collaboration on digital satellite data applications and analysis tools, and has been used by the World Meteorological Organization in an effort to provide digital satellite data to developing countries in Central America and the Caribbean. The RAMSDIS project was innovative for many reasons. This article describes the unique approaches that made the project a success and details RAMSDIS utilization within the NWS and NOAA. The next phase of RAMSDIS implementation in the international meteorological community is also described. C1 NOAA, Natl Environm Satellite Data & Informat Serv, Reg & Mesoscale Meteorol Team, Ft Collins, CO USA. NOAA, Natl Weather Serv, Western Reg Headquarters, Salt Lake City, UT USA. NOAA, Natl Environm Satellite Data & Informat Serv, Off Res & Applicat, Camp Springs, MD USA. RP Molenar, DA (reprint author), RAMM, NESDIS, CIRA Bldg,CSU Foothills Campus,W LaPorte Ave, Ft Collins, CO 80523 USA. RI Molenar, Debra/F-5615-2010 NR 12 TC 5 Z9 5 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 MAY PY 2000 VL 81 IS 5 BP 1019 EP 1030 DI 10.1175/1520-0477(2000)081<1019:RCTNSD>2.3.CO;2 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 306FY UT WOS:000086587700003 ER PT J AU Johns, RH Evans, JS AF Johns, RH Evans, JS TI Comments on "A climatology of derecho-producing mesoscale convective systems in the central and eastern United States, 1986-95. Part I: Temporal and spatial distribution" SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Letter C1 NOAA, NWS, Storm Predict Ctr, Norman, OK 73069 USA. RP Johns, RH (reprint author), NOAA, NWS, Storm Predict Ctr, Norman, OK 73069 USA. NR 9 TC 12 Z9 12 U1 0 U2 3 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 MAY PY 2000 VL 81 IS 5 BP 1049 EP 1054 DI 10.1175/1520-0477(2000)081<1049:COACOD>2.3.CO;2 PG 6 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 306FY UT WOS:000086587700007 ER PT J AU Beckvar, N Salazar, S Salazar, M Finkelstein, K AF Beckvar, N Salazar, S Salazar, M Finkelstein, K TI An in situ assessment of mercury contamination in the Sudbury River, Massachusetts, using transplanted freshwater mussels (Elliptio complanata) SO CANADIAN JOURNAL OF FISHERIES AND AQUATIC SCIENCES LA English DT Article ID ATOMIC FLUORESCENCE DETECTION; GAS-CHROMATOGRAPHY; INORGANIC MERCURY; WATER MUSSELS; METHYLMERCURY; TEMPERATURE; UNIONIDAE; SEDIMENTS; DYNAMICS; METALS AB Freshwater mussels (Elliptio complanata) were transplanted into the Sudbury River, Massachusetts, to evaluate the bioavailability of total Hg and methyl mercury (MeHg) and the potential impacts to resident species. The principal Hg source is the Nyanza Superfund site, a former textile dye production facility. Mussels (initial tissue concentrations = 640 ng Hg.g dry weight(-1) and 120 ng MeHg.g dry weight(-1)) were transplanted to eight locations in the Sudbury River watershed for 12 weeks. Tissue total Hg concentration increased significantly in mussels at the station closest to the Nyanza site (950 ng Hg.g dry weight(-1)). Mussel growth, which increased downstream with distance away from the site, was significantly negatively correlated with tissue concentrations of total Hg (r = -0.95) and positively correlated with average temperature (r = 0.85). Due to growth differences, uptake was best assessed by changes in content. Tissue total Hg and MeHg burdens were greatest in mussels at two stations closest to the Nyanza site, with less Hg accumulated in downstream mussels. However, the MeHg content in mussel tissue increased significantly at all Sudbury River stations, indicating that MeHg was bioavailable in all portions of the river evaluated. C1 NOAA, Off Response & Restorat, Seattle, WA 98115 USA. Appl Biomonitoring, Kirkland, WA 98034 USA. RP Beckvar, N (reprint author), NOAA, Off Response & Restorat, 7600 Sand Point Way NE, Seattle, WA 98115 USA. NR 35 TC 14 Z9 15 U1 1 U2 12 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 MAY PY 2000 VL 57 IS 5 BP 1103 EP 1112 DI 10.1139/cjfas-57-5-1103 PG 10 WC Fisheries; Marine & Freshwater Biology SC Fisheries; Marine & Freshwater Biology GA 318FL UT WOS:000087273200022 ER PT J AU Rea, LD Rosen, DAS Trites, AW AF Rea, LD Rosen, DAS Trites, AW TI Metabolic response to fasting in 6-week-old Steller sea lion pups (Eumetopias jubatus) SO CANADIAN JOURNAL OF ZOOLOGY-REVUE CANADIENNE DE ZOOLOGIE LA English DT Article ID ALASKA; VALUES AB Four Steller sea lions (Eumetopias jubatus) aged 6 weeks were fasted for 2.5 d to determine how young pups mobilize energy reserves during short periods of fasting similar to those experienced in the wild. At 6 weeks of age, the pups lost 5.1 +/- 0.3% of their body mass during 2 d of fasting, with an average daily mass loss of 0.7 +/- 0.1 kg.d(-1). Plasma blood urea nitrogen (BUN) concentration increased significantly from 3.0 +/- 0.1 mM, after an overnight fast, to 4.8 +/- 0.5 mM, after 2.5 d of fasting. It is apparent that BUN levels are quickly depressed, since after only an overnight fast, these pups showed BUN levels 2- to 4-fold lower than those measured after the same pups, when 9 months of age, had recently been fed fish. Plasma ketone body (beta-HBA) concentrations of the 6-week-old pups increased significantly from 0.32 +/- 0.08 to 0.42 +/- 0.08 mM between 0.5 and 1.5 d of fasting. There was no significant change in mean plasma concentration beyond 1.5 d, owing to variable individual responses to extended fasting. Plasma beta-HBA levels at 9 months of age ranged from 0.07 to 0.18 mM. Six-week-old Steller sea lion pups showed blood chemistry consistent with metabolic adaptation to fasting within 16 h but were unable to sustain a protein-sparing metabolism for a prolonged period. The pups appeared to revert to protein catabolism after only 2.5 d of fasting. This infers a decrease in lipid catabolism that might be due to the depletion of available lipid resources. C1 Univ Cent Florida, Dept Biol, Orlando, FL 32816 USA. Natl Marine Fisheries Serv, Natl Marine Mammal Lab, NOAA, Seattle, WA 98115 USA. Univ British Columbia, Fisheries Ctr, Marine Mammal Res Unit, Vancouver, BC V6T 1Z4, Canada. RP Rea, LD (reprint author), Univ Cent Florida, Dept Biol, POB 162368, Orlando, FL 32816 USA. NR 19 TC 24 Z9 24 U1 0 U2 5 PU NATL RESEARCH COUNCIL CANADA PI OTTAWA PA RESEARCH JOURNALS, MONTREAL RD, OTTAWA, ONTARIO K1A 0R6, CANADA SN 0008-4301 J9 CAN J ZOOL JI Can. J. Zool.-Rev. Can. Zool. PD MAY PY 2000 VL 78 IS 5 BP 890 EP 894 DI 10.1139/cjz-78-5-890 PG 5 WC Zoology SC Zoology GA 324MA UT WOS:000087624400026 ER PT J AU Wu, AL Deng, CH Deng, L AF Wu, AL Deng, CH Deng, L TI Expansion of potential 1/r(12) of atomic systems in hyper-spherical harmonics SO CHINESE JOURNAL OF CHEMISTRY LA English DT Article DE expansion of potential 1/r(12); atomic system; hyper-spherical harmonics; expansion coefficient AB The expansion coefficient C-\L\(D) Of Coulomb potential 1/r(12) of atomic system in hyper-spherical harmonics is derived and the explicit expression is given. C1 Shandong Univ Technol, Dept Math & Phys, Shandong 250061, Peoples R China. Shandong Univ, Inst Theoret Chem, Jinan 250100, Shandong, Peoples R China. Natl Inst Stand & Technol, Atom Phys Div, Gaithersburg, MD 20899 USA. RP Wu, AL (reprint author), Shandong Univ Technol, Dept Math & Phys, Shandong 250061, Peoples R China. NR 4 TC 1 Z9 1 U1 0 U2 1 PU SCIENCE PRESS PI BEIJING PA 16 DONGHUANGCHENGGEN NORTH ST, BEIJING 100717, PEOPLES R CHINA SN 1001-604X J9 CHINESE J CHEM JI Chin. J. Chem. PD MAY-JUN PY 2000 VL 18 IS 3 BP 271 EP 274 PG 4 WC Chemistry, Multidisciplinary SC Chemistry GA 323CC UT WOS:000087546400002 ER PT J AU Hall, A Manabe, S AF Hall, A Manabe, S TI Suppression of ENSO in a coupled model without water vapor feedback SO CLIMATE DYNAMICS LA English DT Article ID OCEAN-ATMOSPHERE MODEL; SOUTHERN OSCILLATION; SIMULATED ENSO; CIRCULATION; CO2 AB We examine 800-year time series of internally generated variability in both a coupled ocean-atmosphere model where water vapor anomalies are not allowed to interact with longwave radiation and one where they are. The ENSO-like phenomenon in the experiment without water vapor feedback is drastically suppressed both in amplitude and geographic extent relative to the experiment with water vapor feedback. Surprisingly, the reduced amplitude of ENSO-related sea surface temperature anomalies in the model without water vapor feedback cannot be attributed to greater longwave damping of sea surface temperature, (Differences between the two experiments in radiative feedback due to clouds counterbalance almost perfectly the differences in radiative feedback due to water vapor.) Rather, the interaction between water vapor anomalies and longwave radiation affects the ENSO-like phenomenon through its influence on the vertical structure of radiative heating: Because of the changes in water vapor associated with it, a given warm equatorial Pacific sea surface temperature anomaly is associated with a radiative heating profile that is much more gravitationally unstable when water vapor feedback is present. The warm sea surface temperature anomaly therefore results in more convection in the experiment with water vapor feedback. The increased convection, in turn, is related to a larger westerly wind-stress anomaly, which creates a larger decrease in upwelling of cold water, thereby enhancing the magnitude of the original warm sea surface temperature anomaly. In this manner, the interaction between water vapor anomalies and longwave radiation magnifies the air-sea interactions at the heart of the ENSO phenomenon; without this interaction, the coupling between sea surface temperature and wind stress is effectively reduced, resulting in smaller amplitude ENSO episodes with a more limited geographical extent. C1 Princeton Univ, Atmospher & Ocean Sci Program, Princeton, NJ 08544 USA. Columbia Univ, Lamont Doherty Earth Observ, Palisades, NY 10964 USA. Inst Global Change Res, FRSGC, Minato Ku, Tokyo 105, Japan. RP Hall, A (reprint author), Princeton Univ, Atmospher & Ocean Sci Program, Princeton, NJ 08544 USA. RI Hall, Alex/D-8175-2014 NR 22 TC 3 Z9 5 U1 0 U2 1 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 MAY PY 2000 VL 16 IS 5 BP 393 EP 403 DI 10.1007/s003820050336 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 321JM UT WOS:000087452400006 ER PT J AU Worthington, SE Krauss, M AF Worthington, SE Krauss, M TI Effective fragment potentials and the enzyme active site SO COMPUTERS & CHEMISTRY LA English DT Article; Proceedings Paper CT 5th Conference on Computers in Chemistry/Workshop on New Trends in Computational Methods for Large Molecular Systems CY JUL 01-06, 1999 CL SZKLARSKA, POLAND SP Polish Amer Sklodowsha Curie Foundation DE effective fragment potentials; chorismate mutase; ribonuclease A; enzyme active site; binding conformation; mutant ID QUANTUM-MECHANICAL CALCULATIONS; DISTRIBUTED MULTIPOLE ANALYSIS; CHORISMATE MUTASE; BACILLUS-SUBTILIS; TRANSITION-STATE; RIBONUCLEASE-A; PREPHENATE REARRANGEMENT; CLAISEN REARRANGEMENT; VANADATE COMPLEX; SOLVATION AB Optimization of the binding conformation of a substrate in an enzyme active site using ab initio quantum chemistry methods are intractable since the active site comprises several hundred atoms. However, the active site can be decomposed into an active and spectator region where the spectator residues are represented by effective fragment potentials and reducing the number of all-electron atoms involved in the chemistry to a reasonable level. The effective fragment potentials for electrostatics and polarization are implemented in GAMESS but the repulsive and charge transfer potentials are fit to interaction energies of water with models of the residues. These repulsive/charge transfer potentials are generated for the protein residues and the EFP are then used to optimize binding of a transition state analogue to chorismate mutase (B. subtilis) and small dianions to ribonuclease A. For chorismate mutase the calculated binding conformation compares well to the comparable X-ray structure. The binding of the inhibitor to the glutamate/glutamine mutant active site is then predicted with the optimization including the glutamine residue constrained only at the C alpha atom. The binding conformations suggest important roles for tyr108 and arg63, which have not been noted earlier. The electrostatic stabilization of the transition state by the active site charge distribution has to be augmented by a specific electronic activation by glu78. In ribonuclease A, the protons are found to move to provide a clustering of the charges to bind the small dianions, phosphate, thiophosphate, and sulfate. (C) 2000 Elsevier Science Ltd. All rights reserved. C1 Natl Inst Stand & Technol, Ctr Adv Res Biotechnol, Rockville, MD 20850 USA. RP Krauss, M (reprint author), Natl Inst Stand & Technol, Ctr Adv Res Biotechnol, 9600 Gudelsky Dr, Rockville, MD 20850 USA. NR 33 TC 14 Z9 14 U1 0 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0097-8485 J9 COMPUT CHEM JI Comput. Chem. PD MAY PY 2000 VL 24 IS 3-4 BP 275 EP 285 DI 10.1016/S0097-8485(99)00066-2 PG 11 WC Chemistry, Multidisciplinary; Computer Science, Interdisciplinary Applications SC Chemistry; Computer Science GA 311EG UT WOS:000086871300005 PM 10815997 ER PT J AU Beichl, I Sullivan, F AF Beichl, I Sullivan, F TI A = B? SO COMPUTING IN SCIENCE & ENGINEERING LA English DT Article C1 NIST, Informat Lab, Gaithersburg, MD 20899 USA. IDA, Ctr Comp Sci, Inst Def Anal, Bowie, MD 20715 USA. RP Beichl, I (reprint author), NIST, Informat Lab, Gaithersburg, MD 20899 USA. NR 7 TC 1 Z9 1 U1 0 U2 0 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1314 USA SN 1521-9615 J9 COMPUT SCI ENG JI Comput. Sci. Eng. PD MAY-JUN PY 2000 VL 2 IS 3 BP 84 EP 87 DI 10.1109/5992.841801 PG 4 WC Computer Science, Interdisciplinary Applications SC Computer Science GA 307BA UT WOS:000086632500019 ER PT J AU Castro, JI AF Castro, JI TI The biology of the nurse shark, Ginglymostoma cirratum, off the Florida east coast and the Bahama Islands SO ENVIRONMENTAL BIOLOGY OF FISHES LA English DT Article DE elasmobranch; name; maximum size; size at maturity; reproduction; reproductive cycle; gestation; lecithotrophy; brood size; diet AB The nurse shark is an extremely abundant shallow water species in Florida and the Caribbean, yet its biology is poorly known. Moreover, there is a great deal of misinformation about it in the literature. The maximum size and weight attained by the nurse shark have often been exaggerated. None of the specimens measured in this study exceeded 265 cm TL and 114.5 kg, and none of the specimens actually measured by other researchers exceeded 280 cm. Females reach maturity at a length of 223-231 cm, or at 86% of their maximum size. Males reach maturity between 214 and 214.6 cm in length or at about 83% of their maximum size. Mating primarily occurs from mid-June to early July. The embryos are enclosed in sturdy egg capsules for the first 12-14 weeks of gestation. In a gravid female, the embryos are at different stages of development during the first four months of gestation. Embryos are lecithotrophic and there is no evidence of any supplemental mode of embryonic nourishment. Embryos measure 28-30.5 cm at birth. The gestation period is estimated at about five to six months. Brood sizes are large, ranging from 21 to 50 young, with a median of 34 young. The reproductive cycle of the nurse shark consists of a five to six-month gestation period and a two-year ovarian cycle. Thus, the reproductive cycle is biennial and a female produces a brood every two years. The nurse shark is an opportunistic predator that consumes a wide range of small fishes, primarily grunts (Haemulidae). C1 NOAA, NMFS, SE Fisheries Sci Ctr, Miami, FL 33149 USA. Mote Marine Lab, Ctr Shark Res, Sarasota, FL 34236 USA. RP Castro, JI (reprint author), NOAA, NMFS, SE Fisheries Sci Ctr, 75 Virginia Beach Dr, Miami, FL 33149 USA. EM jose.castro@noaa.gov NR 39 TC 50 Z9 56 U1 6 U2 23 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0378-1909 EI 1573-5133 J9 ENVIRON BIOL FISH JI Environ. Biol. Fishes PD MAY PY 2000 VL 58 IS 1 BP 1 EP 22 DI 10.1023/A:1007698017645 PG 22 WC Ecology; Marine & Freshwater Biology SC Environmental Sciences & Ecology; Marine & Freshwater Biology GA 306WT UT WOS:000086622100001 ER PT J AU Hard, JJ Berejikian, BA Tezak, EP Schroder, SL Knudsen, CM Parker, LT AF Hard, JJ Berejikian, BA Tezak, EP Schroder, SL Knudsen, CM Parker, LT TI Evidence for morphometric differentiation of wild and captively reared adult coho salmon: a geometric analysis SO ENVIRONMENTAL BIOLOGY OF FISHES LA English DT Article DE relative warps; thin-plate spline; domestication; reproductive behavior; salmonid fish ID SOUTHERN BRITISH-COLUMBIA; ONCORHYNCHUS-KISUTCH; PACIFIC SALMON; PINK SALMON; REPRODUCTIVE-BEHAVIOR; ATLANTIC SALMON; BREEDING COMPETITION; BODY MORPHOLOGY; SOCKEYE-SALMON; PUGET-SOUND AB As part of a comprehensive genetic evaluation of reproduction in naturally spawning coho salmon, Oncorhynchus kisutch, we examined morphometric variation in captively reared and wild adults from Hood Canal, Washington (U.S.A.) for evidence of differentiation between these groups. We collected captively reared fish as parr from two stocks and reared to adulthood at a freshwater hatchery, maturing in 1995 and 1996; we sampled closely size-matched wild fish as they returned to a neighboring stream in both years. Multivariate analysis of shape variation by Procrustes coordinates, visualized by thin-plate splines, indicated that the captively reared adults were differentiated from the wild fish by sharply reduced sexual dimorphism as well as smaller heads and less hooked snouts, increased trunk depth, larger caudal peduncles, shorter dorsal fins, larger hindbodies and a reduction in body streamlining. The differences between the captively reared and wild fish were similar to but more pronounced than some differences previously reported between hatchery and wild coho salmon. The magnitude and pattern of differences suggested that at least some of them were environmentally induced. Shape variation showed an allometric relationship with variation in body (measured as centroid) size. Morphometric variation was a poor correlate of most spawning behaviors. Nevertheless, our results suggest that the morphometric consequences of captive rearing for mate selection and reproductive activity of spawning fish may limit its effectiveness as a restorative tool. C1 NOAA, Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, Seattle, WA 98112 USA. Natl Marine Fisheries Serv, Manchester Marine Expt Stn, Manchester, WA 98353 USA. Washington Dept Fish & Wildlife, Olympia, WA 98501 USA. Frank Orth & Associates Inc, Bellevue, WA 98004 USA. RP Hard, JJ (reprint author), NOAA, Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, 2725 Montlake Blvd E, Seattle, WA 98112 USA. EM jeff.hard@noaa.gov RI Hard, Jeffrey/C-7229-2009; Rohlf, F/A-8710-2008 NR 42 TC 52 Z9 54 U1 1 U2 12 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0378-1909 J9 ENVIRON BIOL FISH JI Environ. Biol. Fishes PD MAY PY 2000 VL 58 IS 1 BP 61 EP 73 DI 10.1023/A:1007646332666 PG 13 WC Ecology; Marine & Freshwater Biology SC Environmental Sciences & Ecology; Marine & Freshwater Biology GA 306WT UT WOS:000086622100006 ER PT J AU Gale, RW Long, ER Schwartz, TR Tillitt, DE AF Gale, RW Long, ER Schwartz, TR Tillitt, DE TI Evaluation of planar halogenated and polycyclic aromatic hydrocarbons in estuarine sediments using ethoxyresorufin-O-deethylase induction of H4IIE cells SO ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY LA English DT Article DE bioassay; H4IIE; toxicity; sediments ID NEW-JERSEY; FLY-ASH; 2,3,7,8-TETRACHLORODIBENZO-P-DIOXIN EQUIVALENTS; CYTOCHROME-P450IA1 INDUCTION; POLYCHLORINATED BIPHENYL; ENVIRONMENTAL-SAMPLES; QUALITY GUIDELINES; BIOASSAY; DIOXIN; BAY AB Polycyclic aromatic hydrocarbons (PAHs) and planar halogenated hydrocarbons (PAHs), including polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), and biphenyls (PCBs) were determined in fractionated sediment extracts from the Hudson-Raritan estuary and Newark Bay, New Jersey, USA, as part of a comprehensive risk assessment. Contributions of PCDDs/PCDFs, PCBs, and PAHs to the total toxic equivalents (TEQs) were measured using an H4IIE bioassay and calculated from instrumentally determined concentrations using international toxic equivalency factors. The H4IIE TEQs of whole and fractionated extracts were compared to calculated TEQs to investigate the applicability of the bioassay approach for evaluating 7-ethoxyresorufin-O-deethylease induction by PHHs and PAHs present together in complex mixtures. Although 2,3,7,8-tetrachlorodibenzo-p-dioxin contributed from 41 to 79% of the calculated TEQs from PCDDs/PCDFs and planar PCBs in all sediments sampled, the PAM-containing fractions accounted for >80% of the total TEQs determined either instrumentally or by bioassay. Calculated TEQs from PAHs, based on reported toxic equivalency factors for only seven PAHs, were severalfold greater than the bioassay-derived TEQs of PAM-only fractions of the sediment extracts. Significant correlations were observed between bioassay and instrumentally determined toxic equivalents in the more purified fractions but not in fractions only purified by size-exclusion or argentate chromatographies alone. C1 US Geol Survey, Biol Resources Div, Columbia Environm Res Ctr, Columbia, MO 65201 USA. Natl Ocean & Atmospher Adm, Off Ocean Resources Conservat & Assessment, Seattle, WA 98115 USA. RP Gale, RW (reprint author), US Geol Survey, Biol Resources Div, Columbia Environm Res Ctr, 4200 New Haven Rd, Columbia, MO 65201 USA. NR 38 TC 31 Z9 31 U1 0 U2 2 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 MAY PY 2000 VL 19 IS 5 BP 1348 EP 1359 DI 10.1897/1551-5028(2000)019<1348:EOPHAP>2.3.CO;2 PG 12 WC Environmental Sciences; Toxicology SC Environmental Sciences & Ecology; Toxicology GA 307DC UT WOS:000086637300018 ER PT J AU MacDonald, DD Dipinto, LM Field, J Ingersoll, CG Long, ER Swartz, RC AF MacDonald, DD Dipinto, LM Field, J Ingersoll, CG Long, ER Swartz, RC TI Development and evaluation of consensus-based sediment effect concentrations for polychlorinated biphenyls SO ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY LA English DT Article DE polychlorinated biphenyls; mixtures; sediment quality guidelines; sediment; toxicity ID TIDAL RIVER SEDIMENTS; ACID-VOLATILE SULFIDE; DIBENZO-PARA-DIOXINS; QUALITY GUIDELINES; DC AREA; RHEPOXYNIUS-ABRONIUS; INFAUNAL AMPHIPOD; MARINE-SEDIMENTS; TOXICITY; CONTAMINANTS AB Sediment-quality guidelines (SQGs) have been published for polychlorinated biphenyls (PCBs) using both empirical and theoretical approaches. Empirically based guidelines have been developed using the screening-level concentration, effects range, effects level, and apparent effects threshold approaches. Theoretically based guidelines have been developed using the equilibrium-partitioning approach. Empirically-based guidelines were classified into three general categories. in accordance with their original narrative intents, and used to develop three consensus-based sediment effect concentrations (SECs) for total PCBs (tPCBs), including a threshold effect concentration, a midrange effect concentration, and an extreme effect concentration. Consensus-based SECs were derived because they estimate the central tendency of the published SQGs and, thus, reconcile the guidance values that have been derived using various approaches. Initially, consensus-based SECs for tPCBs were developed separately for freshwater sediments and fur marine and estuarine sediments. Because the respective SECs were statistically similar, the underlying SQGs were subsequently merged and used to formulate more generally applicable SECs. The three consensus-based SECs were then evaluated for reliability using matching sediment chemistry and toxicity data from field studies, dose-response data from spiked-sediment toxicity tests, and SQGs derived from the equilibrium-partitioning approach. The results of this evaluation demonstrated that the consensus-based SECs can accurately predict both the presence and absence of toxicity in field-collected sediments. Importantly, the incidence of toxicity increases incrementally with increasing concentrations of tPCBs. Moreover, the consensus-based SECs are comparable to the chronic toxicity thresholds that have been estimated from dose-response data and equilibrium-partitioning models. Therefore, consensus-based SECs provide a unifying synthesis of existing SQGs, reflect causal rather than correlative effects, and accurately predict sediment toxicity in PCB-contaminated sediments. C1 MacDonald Environm Sci Ltd, Nanaimo, BC V9X 1W5, Canada. Natl Ocean & Atmospher Adm, ORCA, Damage Assessment Ctr, Silver Spring, MD 20910 USA. NOAA, Hazardous Mat Response & Assessment Div, Seattle, WA 98115 USA. US Geol Survey, Columbia Environm Res Ctr, Columbia, MO 65201 USA. Natl Ocean & Atmospher Adm, Coastal Monitoring & Bioeffects Assessment Div, Seattle, WA 98115 USA. RP MacDonald, DD (reprint author), MacDonald Environm Sci Ltd, 2376 Yellow Point Rd, Nanaimo, BC V9X 1W5, Canada. NR 50 TC 82 Z9 95 U1 2 U2 31 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 MAY PY 2000 VL 19 IS 5 BP 1403 EP 1413 DI 10.1897/1551-5028(2000)019<1403:DAEOCB>2.3.CO;2 PG 11 WC Environmental Sciences; Toxicology SC Environmental Sciences & Ecology; Toxicology GA 307DC UT WOS:000086637300024 ER PT J AU Livingston, RJ Lewis, FG Woodsum, GC Niu, XF Galperin, B Huang, W Christensen, JD Monaco, ME Battista, TA Klein, CJ Howell, RL Ray, GL AF Livingston, RJ Lewis, FG Woodsum, GC Niu, XF Galperin, B Huang, W Christensen, JD Monaco, ME Battista, TA Klein, CJ Howell, RL Ray, GL TI Modelling oyster population response to variation in freshwater input SO ESTUARINE COASTAL AND SHELF SCIENCE LA English DT Article DE oyster fisheries; statistical models; estuarine circulation; river flow; predation; mortality rates; growth rates; Gulf of Mexico ID HUDSON-RARITAN ESTUARY; PERKINSUS-MARINUS; 3-DIMENSIONAL SIMULATION; CRASSOSTREA-VIRGINICA; APALACHICOLA BAY; EASTERN OYSTERS; DELAWARE BAY; RIVER SYSTEM; FLORIDA; WATER AB This paper describes the linkage of a three-dimensional hydrodynamic circulation model with descriptive and experimental biological data concerning oyster (Crassostrea virginica) population dynamics in the Apalachicola Estuary (Florida, U.S.A.). Our intent was to determine the direct and indirect role of Apalachicola River flow in the maintenance of oyster production. Results of a monthly field sampling programme conducted on the oyster reefs in the Apalachicola system during 1985-1986 were used to develop statistical models relating several life-history characteristics of oysters to physical-chemical aspects of water quality. The same life-history characteristics were related statistically to output from a circulation model of Apalachicola Bay. Highest oyster densities and overall bar growth were found in the vicinity of the confluence of high salinity water moving westwards from St George Sound and river-dominated (low salinity) water moving south and eastwards from East Bay. With the exception of models for oyster mortality, the predictive capability of results from the parallel modelling efforts was low. A time-averaged model was developed for oyster mortality during the summer of 1985 by running a regression analysis with averaged predictors derived from the hydrodynamic model and observed (experimental) mortality rates throughout the estuary. A geographic information system was then used to depict the results spatially and to compare the extent of expected mortality in 1985 and 1986. High salinity, relatively low-velocity current patterns, and the proximity of a given oyster bar to entry points of saline Gulf water into the bay were important factors that contribute to increased oyster mortality. Mortality was a major determinant of oyster production in the Apalachicola Estuary with predation as a significant aspect of such mortality. By influencing salinity levels and current patterns throughout the bay, the Apalachicola River was important in controlling such mortality. Oyster production rates in the Apalachicola system depend on a combination of variables that are directly and indirectly associated with freshwater input as modified by wind, tidal factors, and the physiography of the bay. River flow reduction, whether through naturally occurring droughts, through increased upstream anthropogenous (consumptive) water use, or a combination of the two, could have serious adverse consequences for oyster populations. By coupling hydrodynamic modelling with descriptive and experimental biological data, we were able to determine the effects of potential freshwater diversions on oyster production in Apalachicola Bay. (C) 2000 Academic Press. C1 Florida State Univ, Ctr Aquat Res & Resource Management, Tallahassee, FL 32306 USA. NW Florida Water Management Dist, Havana, FL 32333 USA. Florida State Univ, Dept Stat, Tallahassee, FL 32306 USA. Univ S Florida, Dept Marine Sci, St Petersburg, FL 33701 USA. Florida A&M Univ, Coll Engn, Tallahassee, FL 32311 USA. NOAA, Natl Ocean Serv, Ctr Coastal Monitoring & Assessment, Silver Spring, MD 20910 USA. USA, Corps Engineers, Waterways Expt Stn, Coastal Ecol Branch, Vicksburg, MS 39180 USA. RP Livingston, RJ (reprint author), Florida State Univ, Ctr Aquat Res & Resource Management, Tallahassee, FL 32306 USA. NR 58 TC 66 Z9 69 U1 1 U2 26 PU ACADEMIC PRESS LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 0272-7714 J9 ESTUAR COAST SHELF S JI Estuar. Coast. Shelf Sci. PD MAY PY 2000 VL 50 IS 5 BP 655 EP 672 DI 10.1006/ecss.1999.0597 PG 18 WC Marine & Freshwater Biology; Oceanography SC Marine & Freshwater Biology; Oceanography GA 323LE UT WOS:000087566200006 ER PT J AU Bryant, RA Donbar, JM Driscoll, JF AF Bryant, RA Donbar, JM Driscoll, JF TI Acetone laser induced fluorescence for low pressure/low temperature flow visualization SO EXPERIMENTS IN FLUIDS LA English DT Article ID GAS-PHASE; 3-PENTANONE; DIAGNOSTICS AB Acetone fluorescence provides a useful way to visualize the fluid mixing process within supersonic wind tunnels, some of which operate in the low temperature (240-300 K) and low pressure range (0.1-1 atm). Measurements are presented to quantify the dependence of the acetone laser induced fluorescence (LIF) signal on temperature and pressure in this range. The temperature and pressure sensitivity of the acetone LIF signal resulted in less than an 8% variation over the experimental conditions for a laser excitation wavelength of 266 nm. Condensation of the acetone vapor was identified as a potential problem for this diagnostic technique. Methods to prevent and check for condensation are discussed. C1 Univ Michigan, Dept Aerosp Engn, Ann Arbor, MI 48109 USA. RP Bryant, RA (reprint author), Natl Inst Stand & Technol, Bldg & Fire Res Lab, Gaithersburg, MD 20899 USA. NR 16 TC 22 Z9 22 U1 1 U2 15 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0723-4864 J9 EXP FLUIDS JI Exp. Fluids PD MAY PY 2000 VL 28 IS 5 BP 471 EP 476 DI 10.1007/s003480050407 PG 6 WC Engineering, Mechanical; Mechanics SC Engineering; Mechanics GA 316WD UT WOS:000087190300010 ER PT J AU Butler, JL Folkvord, A AF Butler, JL Folkvord, A TI Section 2: Estimation of fish age and growth SO FISHERIES RESEARCH LA English DT Editorial Material C1 SW Fisheries Sci Ctr, Natl Marine Fisheries Serv, La Jolla, CA 92038 USA. RP Univ Bergen, Dept Fisheries & Marine Biol, N-5020 Bergen, Norway. EM arild.folkvord@ifm.uib.no OI Folkvord, Arild/0000-0002-4763-0590 NR 3 TC 2 Z9 2 U1 1 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0165-7836 EI 1872-6763 J9 FISH RES JI Fish Res. PD MAY PY 2000 VL 46 IS 1-3 BP 51 EP 52 DI 10.1016/S0165-7836(00)00132-6 PG 2 WC Fisheries SC Fisheries GA 317ZY UT WOS:000087259700007 ER PT J AU Schirripa, MJ Trexler, JC AF Schirripa, MJ Trexler, JC TI Effects of mortality and gear selectivity on the fish otolith radius-total length relation SO FISHERIES RESEARCH LA English DT Article; Proceedings Paper CT 2nd International Symposium on Fish Otolith Research and Application CY JUN, 1998 CL BERGEN, NORWAY DE back-calculation; gear selectivity; otoliths ID SOMATIC GROWTH; BIOENERGETICS MODEL; MORONE-SAXATILIS; STRIPED BASS; SIZE; AGE AB The effects of mortality and gear selectivity on the otolith radius-total length relation (OR-TL), an important component of the back-calculation of length-at-age process, were simulated using a somatic-otolith bioenergetics population model. Four gear selectivities were examined and used to produce fishery-dependent samples for statistical analysis. Samples taken with selective gears produced OR-TLs with significantly different gamma-intercepts than those from an unfished population; significant differences were also found between gear selectivities. The OR-TL gamma-intercept of a non-selectively fished population was found to be systematically influenced downward by total mortality as a result of a decrease in the number of larger fish. This influence was removed using the mean otolith radius-at-age and mean length-at-age in the OR-TL regression, which resulted in more accurate estimates of back-calculated size-at-age; the best estimates were made using only the last annulus in the calculation. The results of this study imply that, rather than a fixed value, the gamma-intercept of the OR-TL and the underlying population growth rate are more accurately considered dynamic parameters that changes as a cohort ages and experiences mortality. Use of the population growth rate and gamma-intercept in the back-calculation of size-at-age needs to account for the degree and selectivity of recent fishing mortality of the population under investigation. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Natl Marine Fisheries Serv, SE Fisheries Sci Ctr, Miami Lab, Miami, FL 33149 USA. RP Schirripa, MJ (reprint author), Natl Marine Fisheries Serv, SE Fisheries Sci Ctr, Miami Lab, 75 Virginia Beach Dr, Miami, FL 33149 USA. NR 16 TC 3 Z9 3 U1 0 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0165-7836 J9 FISH RES JI Fish Res. PD MAY PY 2000 VL 46 IS 1-3 BP 83 EP 89 DI 10.1016/S0165-7836(00)00135-1 PG 7 WC Fisheries SC Fisheries GA 317ZY UT WOS:000087259700010 ER PT J AU Courtney, DL Mortensen, DG Orsi, JA Munk, KM AF Courtney, DL Mortensen, DG Orsi, JA Munk, KM TI Origin of juvenile Pacific salmon recovered from coastal southeastern Alaska identified by otolith thermal marks and coded wire tags SO FISHERIES RESEARCH LA English DT Article; Proceedings Paper CT 2nd International Symposium on Fish Otolith Research and Application CY JUN, 1998 CL BERGEN, NORWAY DE otolith; thermal mark; Pacific salmon; stock origin identification; coded wire tag ID MARINE DISTRIBUTION AB First ocean-year juvenile Pacific salmon (Oncorhynchus spp.) in the marine waters of southeastern Alaska were examined for origin identification in the summers of 1993-1997. Over 31,000 juvenile pink (O. gorbuscha), chum (O. keta), sockeye (O. nerka), coho (O. kisutch), and chinook (O. tshawytscha) salmon were scanned electronically for coded wire tags (cwt's). Cwt's were decoded to indicate tagging origins and release sites. Few (49) fish examined contained cwt's. A sub-sample of the scanned juvenile pink (1,698), chum (1,685), and sockeye (189) salmon were also examined for thermally induced otolith marks (thermal marks). Sagittal otoliths were processed, and thermal mark code patterns were resolved to identify marking facilities and release sites. Many of the pink (45), chum (483), and sockeye (12) salmon examined contained thermal marks. Most recovered cwt's and thermal marks originated in southeastern Alaska. Most thermally marked juveniles had migrated 100-150 km in 60-90 days from release locations in northern and central southeastern Alaska and were recaptured along a primary migration corridor in northern southeastern Alaska. The high proportion (15.1%) of otolith thermal mark recoveries has broad implications for the study of Pacific salmon life histories. In particular, systematic sampling for thermal marks may provide stock-specific insight into the early marine life histories of Pacific salmon species, especially pink and chum salmon, which otherwise are underrepresented in cwt recoveries. (C) 2000 Elsevier Science B.V. All rights reserved. C1 Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr, Auke Bay Lab, Juneau, AK 99801 USA. RP Courtney, DL (reprint author), Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr, Auke Bay Lab, 11305 Glacier Highway, Juneau, AK 99801 USA. NR 15 TC 17 Z9 18 U1 1 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0165-7836 J9 FISH RES JI Fish Res. PD MAY PY 2000 VL 46 IS 1-3 BP 267 EP 278 DI 10.1016/S0165-7836(00)00151-X PG 12 WC Fisheries SC Fisheries GA 317ZY UT WOS:000087259700026 ER PT J AU Kastelle, CR Kimura, DK Jay, SR AF Kastelle, CR Kimura, DK Jay, SR TI Using Pb-210/Ra-226 disequilibrium to validate conventional ages in Scorpaenids (genera Sebastes and Sebastolobus) SO FISHERIES RESEARCH LA English DT Article; Proceedings Paper CT 2nd International Symposium on Fish Otolith Research and Application CY JUN, 1998 CL BERGEN, NORWAY DE Pb-210/Ra-226 disequilibrium; rockfish; Sebastes; Sebastolobus; age determination; radiometric ages ID MACRURONUS-NOVAEZELANDIAE; HOPLOSTETHUS-ATLANTICUS; RADIOMETRIC ANALYSIS; BLUE GRENADIER; ORANGE ROUGHY; LONGEVITY; OTOLITHS; GROWTH; ROCKFISH; PISCES AB Age determination of rockfish (genera Sebastes) and thornyheads (genera Sebastolobus) is typically accomplished by counting growth zones in burnt cross-sections of the otoliths. Interpretation of patterns seen in the otolith's growth zones is often difficult and subjective so age validation is desirable. Unfortunately, age validation has been nonexistent for many of these species. Their biology and life history often make age validation methods used on other species impossible. Therefore, we used radiometric ageing which employs the disequilibrium of Pb-210 and Ra-226 in the otolith. Two methods were used to obtain material from the otoliths: core samples and whole otolith samples. The Pb-210/Ra-226 ratios generally confirmed ageing criteria used for rockfish, but in some cases there was a bias between growth zone counts and radiometric ages. We investigated two potential sources of bias. First, the initial ratio of Pb-210/Ra-226 as incorporated into the otolith may have been overestimated. Second, the otolith core removal process may have inadvertently left excessive amounts of younger aged material not belonging to the core. Both would cause radiometric ages to be biased low. Published by Elsevier Science B.V. C1 NOAA, Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr, Seattle, WA 98115 USA. RP Kastelle, CR (reprint author), NOAA, Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr, Bin 15700,7600 Sand Point Way NE, Seattle, WA 98115 USA. NR 41 TC 22 Z9 23 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0165-7836 J9 FISH RES JI Fish Res. PD MAY PY 2000 VL 46 IS 1-3 BP 299 EP 312 DI 10.1016/S0165-7836(00)00155-7 PG 14 WC Fisheries SC Fisheries GA 317ZY UT WOS:000087259700030 ER PT J AU Margolis, SA Levenson, M AF Margolis, SA Levenson, M TI Certification by the Karl Fischer method of the water content in SRM 2890, water saturated 1-octanol, and the analysis of associated interlaboratory bias in the measurement process SO FRESENIUS JOURNAL OF ANALYTICAL CHEMISTRY LA English DT Article AB The calibration of Karl Fischer instruments and reagents and the compensation for instrumental bias are essential to the accurate measurement of trace levels of water in organic and inorganic chemicals. A stable, nonhygroscopic standard, Water Saturated Octanol, which is compatible with the Karl Fischer reagents, has been prepared. This material, Standard Reference Material (SRM) 2890, is homogeneous and is certified to contain 39.24 +/- 0.85 mg water/mL (expanded uncertainty) of solution (47.3 +/- 1.0 mg water/g solution, expanded uncertainty) at 21.5 degrees C. The solubility of water in 1-octanol has been shown to be nearly constant between 10 degrees C and 30 degrees C (i.e., within 1% of the value at 21.5 degrees C). The results of an inter-laboratory comparison exercise illustrate the utility of SRM 2890 in assessing the accuracy and bias of Karl Fischer instruments and measurements. C1 Natl Inst Stand & Technol, Analyt Chem Div, Gaithersburg, MD 20899 USA. Natl Inst Stand & Technol, Stat Engn Div, Gaithersburg, MD 20899 USA. RP Margolis, SA (reprint author), Natl Inst Stand & Technol, Analyt Chem Div, Stop 8392, Gaithersburg, MD 20899 USA. EM sam.margolis@nist.gov NR 15 TC 33 Z9 36 U1 0 U2 3 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0937-0633 J9 FRESEN J ANAL CHEM JI Fresenius J. Anal. Chem. PD MAY PY 2000 VL 367 IS 1 BP 1 EP 7 DI 10.1007/s002160051589 PG 7 WC Chemistry, Analytical SC Chemistry GA 320YF UT WOS:000087427900001 PM 11227426 ER PT J AU Bath, GE Thorrold, SR Jones, CM Campana, SE McLaren, JW Lam, JWH AF Bath, GE Thorrold, SR Jones, CM Campana, SE McLaren, JW Lam, JWH TI Strontium and barium uptake in aragonitic otoliths of marine fish SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Article ID FORAMINIFERA ORBULINA-UNIVERSA; HIGH-RESOLUTION ANALYSIS; SEA-SURFACE TEMPERATURE; CALCIUM RATIOS; TRACE-ELEMENTS; SHELLS; SR/CA; CORALS; LARVAL; MICROCHEMISTRY AB Minor and trace element analyses of fish otoliths (ear stones) may provide a high-resolution reconstruction of temperature histories and trace element compositions of aquatic systems where other environmental proxies are not available. However, before otoliths can be used to reconstruct water chemistry, it is essential to validate the assumption that trace metals in otoliths are deposited in proportion to dissolved concentrations in the ambient environment. We show, using a marine fish (Leiostomus xanthurus) reared in the laboratory under controlled experimental conditions, that otolith Sr/Ca and Ba/Ca ratios are deposited in proportion to their respective ratios in ambient waters. Temperature significantly affected Sr incorporation but did not affect Ba incorporation in otoliths. Sr/Ca partition coefficients (D(Sr)) were 0.182 and 0.205 at 20 degrees C and 25 degrees C, respectively. The partition coefficients for Ba/Ca were 0.055 at 20 degrees C and 0.062 at 25 degrees C. A nonlinearity in the relationship between D(Ba) and ambient Ba concentrations suggested that extrapolation beyond the Ba levels used in the experiment was not justified. On the basis of our results, it should be possible to reconstruct Sr/Ca and Ba/Ca levels in environments inhabited by fish based on otolith chemistry. Furthermore, Sr/Ca thermometry may also be possible using fish otoliths, but validation of the temperature dependence of Sr/Ca in otoliths will be required. We believe otoliths represent an excellent, and as yet underused, record of the physicochemical properties of both modern and ancient aquatic environments. Copyright (C) 2000 Elsevier Science Ltd. C1 Old Dominion Univ, Dept Biol Sci, Norfolk, VA 23529 USA. Bedford Inst Oceanog, Marine Fish Div, Dartmouth, NS B2Y 4A2, Canada. Natl Res Council Canada, Inst Natl Measurement Stand, Ottawa, ON K1A 0R6, Canada. RP Bath, GE (reprint author), NOAA, NOS, Ctr Coastal Fisheries & Habitat Res, 101 Pivers Isl Rd, Beaufort, NC 28516 USA. EM Gretchen.Bath@noaa.gov RI Thorrold, Simon/B-7565-2012; Campana, Steven/C-3420-2013; OI Thorrold, Simon/0000-0002-1533-7517; Campana, Steven/0000-0001-8802-3976; Lam, Joseph/0000-0001-6402-0535 NR 53 TC 339 Z9 358 U1 10 U2 94 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 MAY PY 2000 VL 64 IS 10 BP 1705 EP 1714 DI 10.1016/S0016-7037(99)00419-6 PG 10 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 313MV UT WOS:000087004200005 ER PT J AU Gischler, E Lomando, AJ Hudson, JH Holmes, CW AF Gischler, E Lomando, AJ Hudson, JH Holmes, CW TI Last interglacial reef growth beneath Belize barrier and isolated platform reefs SO GEOLOGY LA English DT Article DE Belize; Pleistocene; reef; U-series dating ID ISOLATED CARBONATE PLATFORMS; SEA-LEVEL; MASS-SPECTROMETRY; BRITISH-HONDURAS; SOUTHERN LAGOON; CENTRAL-AMERICA; CORAL REEFS; TH-230 AGES; U-234/U-238; PERIOD AB We report the first radiometric dates (thermal-ionization mass spectrometry) from late Pleistocene reef deposits from offshore Belize, the location of the largest modern reef complex in the Atlantic Ocean, The results presented here can be used to explain significant differences in bathymetry, sedimentary facies, and reef development of this major reef area, and the results are significant because they contribute to the knowledge of the regional geology of the eastern Yucatan. The previously held concept of a neotectonically stable eastern Yucatan is challenged. The dates indicate that Pleistocene reefs and shallow-water Limestones, which form the basement of modern reefs in the area, accumulated ca. 125-130 ka. Significant differences in elevation of the samples relative to present sea level (>10 m) have several possible causes. Differential subsidence along a series of continental margin fault blocks in combination with variation in karstification are probably the prime causes, Differential subsidence is presumably related to initial extension and later left-lateral movements along the adjacent active boundary between the North American and Caribbean plates. Increasing dissolution toward the south during Pleistocene sea-level lowstands is probably a consequence of higher precipitation rates in mountainous southern Belize. C1 Univ Frankfurt, Inst Geol Palaontol, D-60054 Frankfurt, Germany. Chevron Overseas Petr Inc, San Ramon, CA 94583 USA. Florida Keys Natl Marine Sanctuary, Key Largo, FL 33037 USA. US Geol Survey, St Petersburg, FL 33701 USA. RP Gischler, E (reprint author), Univ Frankfurt, Inst Geol Palaontol, Senckenberganlage 32-34, D-60054 Frankfurt, Germany. NR 36 TC 23 Z9 23 U1 3 U2 13 PU GEOLOGICAL SOC AMERICA, INC PI BOULDER PA PO BOX 9140, BOULDER, CO 80301-9140 USA SN 0091-7613 J9 GEOLOGY JI Geology PD MAY PY 2000 VL 28 IS 5 BP 387 EP 390 DI 10.1130/0091-7613(2000)28<387:LIRGBB>2.0.CO;2 PG 4 WC Geology SC Geology GA 308BU UT WOS:000086689300001 ER PT J AU Szykman, S Sriram, RD Bochenek, C Racz, JW Senfaute, J AF Szykman, S Sriram, RD Bochenek, C Racz, JW Senfaute, J TI Design repositories: Engineering design's new knowledge base SO IEEE INTELLIGENT SYSTEMS & THEIR APPLICATIONS LA English DT Article C1 Natl Inst Stand & Technol, Mfg Syst Integrat Div, Engn Design Technol Grp, Gaithersburg, MD 20899 USA. Natl Inst Stand & Technol, Design Repository Project, Gaithersburg, MD 20899 USA. RP Szykman, S (reprint author), Natl Inst Stand & Technol, Mfg Syst Integrat Div, Engn Design Technol Grp, Bldg 304,Rm 6, Gaithersburg, MD 20899 USA. NR 11 TC 90 Z9 113 U1 0 U2 11 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1314 USA SN 1094-7167 J9 IEEE INTELL SYST APP JI IEEE Intell. Syst. Appl. PD MAY-JUN PY 2000 VL 15 IS 3 BP 48 EP 55 DI 10.1109/5254.846285 PG 8 WC Computer Science, Artificial Intelligence; Engineering, Electrical & Electronic SC Computer Science; Engineering GA 323DQ UT WOS:000087549900012 ER PT J AU Cho, WS Kanda, M Hwang, HJ Howard, MW AF Cho, WS Kanda, M Hwang, HJ Howard, MW TI A disk-loaded thick cylindrical dipole antenna for validation of an EMC test site from 30 to 300 MHz SO IEEE TRANSACTIONS ON ELECTROMAGNETIC COMPATIBILITY LA English DT Article DE antenna factor; broad-band antenna; DTCD; moment method; site attenuation; site validation ID ATTENUATION AB We propose a new broad-band, short (80-cm-long) disk-loaded thick cylindrical dipole (DTCD) antenna for validation of an electromagnetic compatibility (EMC) test site for the frequency range between 30-300 MHz. In order to achieve broad-band characteristics, we have chosen a thick dipole as DTCD element. Disk loading has been applied to make this dipole shorter. To eliminate any ambiguity in balun characteristics, a commercially available hybrid junction is used as an antenna balun. Thus, the DTCD proposed in this paper is a very short, simple, and cell-defined broad-band antenna that covers the frequency range between 30-300 MHz, The DTCD has an azimuthally. symmetrical radiation pattern and, thus, is very well suited far the validation of an EMC test site, This paper presents the DTCD antenna characteristics such as input impedance, antenna gain, antenna factor, and classical site attenuation, which are calculated by use of the method of moments (MoM). These theoretical antenna factors and classical site attenuations of the DTCD are compared with experiments over the frequency range of 30-300 MHz. They agree with each other to within fl dB in antenna factor and to within +/-2 dB in site attenuation. Our preliminary investigation indicates that an additional DTCD (25 cm long) can cover the frequency range of 300-1000 MHz, Therefore, only two DTCD's will be needed for very accurate calculable classical site attenuation values in order to validate an EMC test site for the entire frequency range between 30-1000 MHz. C1 Korea Testing Lab, EMC Team, Seoul 152053, South Korea. Natl Inst Stand & Technol, Boulder, CO 80303 USA. Chung Ang Univ, Seoul 156756, South Korea. Liberty Labs Inc, Kimballton, IA 51543 USA. RP Cho, WS (reprint author), Korea Testing Lab, EMC Team, Seoul 152053, South Korea. NR 21 TC 11 Z9 12 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 MAY PY 2000 VL 42 IS 2 BP 172 EP 180 DI 10.1109/15.852411 PG 9 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA 337YN UT WOS:000088391200009 ER PT J AU Kanda, M Camell, D de Vreede, JPM Achkar, J Alexander, M Borsero, M Yajima, H Chung, NS Trzaska, H AF Kanda, M Camell, D de Vreede, JPM Achkar, J Alexander, M Borsero, M Yajima, H Chung, NS Trzaska, H TI International comparison GT/RF 86-1 electric field strengths: 29 MHz to 10 GHz SO IEEE TRANSACTIONS ON ELECTROMAGNETIC COMPATIBILITY LA English DT Article DE anechoic chamber; electric field strength; international comparison; open area test site; resistively loaded dipole; transverse electromagnetic (TEM) cell; traveling standard; tuned dipole AB This paper describes the international comparison of electric field strength measurements at frequencies between 27 MHz and 10 GHz (GT/RF 86.1). The participating laboratories were NIST, Pilot Laboratory, USA, National Physical Laboratory, U.K., NMi Van Swinden Laboratorium, The Netherlands, Institute Elettrotecnico National, Italy, Laboratoire Central des Industries Electriques, France, Electrotechnical Laboratory, Japan, Korea Research Institute of Standards and Science, Korea, and Technical University of Wroclaw, Poland. C1 Natl Inst Stand & Technol, Boulder, CO 80303 USA. NMI Van Swinden Lab, NL-2600 AR Delft, Netherlands. Lab Cent Ind Elect, BNM, F-92260 Fontenay Aux Roses, France. Natl Phys Lab, Teddington TW11 0LW, Middx, England. Ist Elettrotecn Nazl Galileo Ferraris, I-10125 Turin, Italy. Electrotech Lab, Tsukuba, Ibaraki 305, Japan. Korea Res Inst Stand & Sci, Taejon 305606, South Korea. Wroclaw Tech Univ, PL-50370 Wroclaw, Poland. NR 0 TC 4 Z9 4 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 0018-9375 J9 IEEE T ELECTROMAGN C JI IEEE Trans. Electromagn. Compat. PD MAY PY 2000 VL 42 IS 2 BP 190 EP 205 DI 10.1109/15.852413 PG 16 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA 337YN UT WOS:000088391200011 ER PT J AU Han, Y Westwater, ER AF Han, Y Westwater, ER TI Analysis and improvement of tipping calibration for ground-based microwave radiometers SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE calibration; ground-based; microwave radiometers ID WATER-VAPOR; RAMAN LIDAR; ATMOSPHERE; AEROSOLS; LIQUID; CLOUD AB The tipping-curve calibration method has been an important calibration technique for ground-based microwave radiometers that measure atmospheric emission at low optical depth. The method calibrates a radiometer system using data taken by the radiometer at two or more viewing angles in the atmosphere. In this method, the relationship between atmospheric opacity and viewing angle is used as a constraint for deriving the system calibration response. Because this method couples the system with radiative transfer theory and atmospheric conditions, evaluations of its performance have been difficult, In this paper, first a data-simulation approach is taken to isolate and analyze those influential factors in the calibration process and effective techniques are developed to reduce calibration uncertainties. Then, these techniques are applied to experimental data. The influential factors include radiometer antenna beam width, radiometer pointing error, mean radiating temperature error, and horizontal inhomogeneity in the atmosphere, as well as some other factors of minor importance. It is demonstrated that calibration uncertainties from these error sources can be large and unacceptable. Fortunately, it was found that by using the techniques reported here, the calibration uncertainties can be largely reduced or avoided. With the suggested corrections, the tipping calibration method can provide absolute accuracy of about or better than 0.5 K. C1 Univ Colorado, Cooperat Inst Res Environm Sci, NOAA, Environm Technol Lab, Boulder, CO 80303 USA. RP Han, Y (reprint author), Univ Colorado, Cooperat Inst Res Environm Sci, NOAA, Environm Technol Lab, Boulder, CO 80303 USA. RI Han, Yong/F-5590-2010 OI Han, Yong/0000-0002-0183-7270 NR 29 TC 114 Z9 124 U1 0 U2 10 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 MAY PY 2000 VL 38 IS 3 BP 1260 EP 1276 DI 10.1109/36.843018 PG 17 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 320EM UT WOS:000087388900012 ER PT J AU Snider, JB AF Snider, JB TI Temporal variability of precipitable water vapor in the North Atlantic SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE atmospheric measurements; meteorology; microwave radiometry; terrestrial atmosphere ID TROPOSPHERE; LIQUID AB Radiometric measurements of precipitable water vapor were made at Porto Santo Island, Madeira, Portugal, over a one-gear period. Temporal variability of the precipitable water vapor is estimated using structure functions, The power law index of the structure functions is compared to values predicted hg a statistical model of water vapor fluctuations. C1 Univ Colorado, NOAA, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. RP Snider, JB (reprint author), Univ Colorado, NOAA, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. NR 8 TC 0 Z9 0 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 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD MAY PY 2000 VL 38 IS 3 BP 1489 EP 1491 DI 10.1109/36.843049 PG 3 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 320EM UT WOS:000087388900043 ER PT J AU Ozgur, M Milanovic, V Zincke, C Gaitan, M Zaghloul, ME AF Ozgur, M Milanovic, V Zincke, C Gaitan, M Zaghloul, ME TI Quasi-TEM characteristic impedance of micromachined CMOS coplanar waveguides SO IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES LA English DT Article DE microelectromechanical devices; micromachining; transmission-line theory ID LINES AB Micromachined coplanar waveguides (CPW's) fabricated in CMOS technology consist of glass-encapsulated metal conductor strips, fully suspended by selective etching of the silicon substrate. The minimum amount of etching necessary for proper operation of the micromachined waveguides is determined by using an isolation criterion. In this paper, the quasi-TEM characteristic impedance of a CPW is derived, including the finite conductor thickness and the thicknesses of surrounding dielectric layers. The employed analytical approach is based on conformal mapping and the partial capacitance technique. The losses both in conductor and dielectric layers are neglected. The analytical results and proposed approximations are verified by integral-equation computation and by measurement of various sample structures. C1 George Washington Univ, Dept Elect Engn & Comp Sci, Washington, DC 20052 USA. NIST, Div Semicond Elect, Gaithersburg, MD 20899 USA. RP Ozgur, M (reprint author), George Washington Univ, Dept Elect Engn & Comp Sci, Washington, DC 20052 USA. NR 9 TC 8 Z9 8 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 0018-9480 J9 IEEE T MICROW THEORY JI IEEE Trans. Microw. Theory Tech. PD MAY PY 2000 VL 48 IS 5 BP 852 EP 854 DI 10.1109/22.841883 PG 3 WC Engineering, Electrical & Electronic SC Engineering GA 314AA UT WOS:000087030900013 ER PT J AU Blessing, GV Hsu, NN Slotwinski, JA Xiang, D AF Blessing, GV Hsu, NN Slotwinski, JA Xiang, D TI Ultrasonics research in the NIST Manufacturing Engineering Laboratory SO IEEE TRANSACTIONS ON ULTRASONICS FERROELECTRICS AND FREQUENCY CONTROL LA English DT Article; Proceedings Paper CT Joint Workshop on Nondestructive Evaluation CY MAY 24-27, 1999 CL PUSAN NATL UNIV, PUSAN, SOUTH KOREA SP Korean Soc Nondestructive Testing, IEEE HO PUSAN NATL UNIV ID BEAM ACOUSTIC MICROSCOPE; WAVES; PROPAGATION; GENERATION; SOLIDS AB The Ultrasonic Standards Group in the Manufacturing Engineering Laboratory of the National Institute of Standards and Technology (NIST) performs research, develops standards, and offers calibration services in support of United States industry. In this paper, two areas of recent experimental research using a thin film piezoelectric polymer are briefly reviewed. One is the development and application of a large aperture lensless line-focus transducer for time-resolved pulsed-wave measurements. The second is the effect of nonlinear wave propagation on pulsed waveforms in industrial ultrasonic nondestructive testing applications. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Johns Hopkins Univ, Baltimore, MD USA. RP Blessing, GV (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NR 24 TC 0 Z9 0 U1 0 U2 2 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 MAY PY 2000 VL 47 IS 3 BP 630 EP 634 DI 10.1109/58.842050 PG 5 WC Acoustics; Engineering, Electrical & Electronic SC Acoustics; Engineering GA 311WX UT WOS:000086910100013 PM 18238590 ER PT J AU Vasconcellos, ECC Allen, MD Zink, LR Evenson, KM AF Vasconcellos, ECC Allen, MD Zink, LR Evenson, KM TI Optically-pumped far-infrared laser lines in hydrazine, methanol, heavy water, and ammonia: New laser lines and frequency measurements SO INTERNATIONAL JOURNAL OF INFRARED AND MILLIMETER WAVES LA English DT Article DE hydrazine; methanol; heavy water; ammonia; new far-infrared laser lines; optically pumped far-infrared laser; laser frequencies; relative intensity AB A far-infrared laser cavity designed to favor short-wavelength laser lines was used to generate optically-pumped far-infrared laser radiation. New far-infrared laser lines were discovered in hydrazine, heavy water, ammonia, and several short-wavelength lines previously discovered in methanol were observed. Wavelength, frequency, and relative intensity measurements were performed on laser lines in the wavelength range 42.4 to 253.7 mu m. Each far-infrared frequency measurement was obtained by mixing the far-infrared radiation with radiation from two reference CO2 lasers and from a microwave synthesizer in a metal-insulator-metal diode. The pump laser was a high-Q Fabry Perot resonator oscillating on 275 grating-selected laser lines lincluding regular, sequence, and hot band lines. C1 Univ Estadual Campinas, Inst Fis Gleb Wataghin, Dept Eletron Quant, BR-13083970 Campinas, SP, Brazil. Natl Inst Stand & Technol, Div Time & Frequency, Boulder, CO 80303 USA. RP Vasconcellos, ECC (reprint author), Univ Estadual Campinas, Inst Fis Gleb Wataghin, Dept Eletron Quant, BR-13083970 Campinas, SP, Brazil. RI Inst. of Physics, Gleb Wataghin/A-9780-2017 NR 9 TC 10 Z9 11 U1 0 U2 0 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 MAY PY 2000 VL 21 IS 5 BP 725 EP 730 DI 10.1023/A:1026456425454 PG 6 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA 312YE UT WOS:000086970900004 ER PT J AU Vasconcellos, ECC Zerbetto, SC Zink, LR Evenson, KM AF Vasconcellos, ECC Zerbetto, SC Zink, LR Evenson, KM TI Optically-pumped far-infrared laser lines of methanol isotopomers: (CH3OH)-C-12, (CH3OD)-C-12, and (CH2DOH)-C-12 SO INTERNATIONAL JOURNAL OF INFRARED AND MILLIMETER WAVES LA English DT Article DE (CD3OH)-C-12; (CH3OD)-C-12; (CH2DOH)-C-12; new far-infrared laser lines; optically-pumped far-infrared laser; laser frequencies; relative intensity; relative polarization; pump-frequency offset AB Twenty-seven new far-infrared laser lines from the isotopomers of methanol: (CD3OH)-C-12 (CH3OD)-C-12, and (CH2DOH)-C-12, were obtained by optically-pumping the molecules with an efficient cw CO2 laser. The CO2 laser provided pumping from regular, sequence, and hot-band CO2 laser transitions. The 2-m long far-infrared cavity was a metal-dielectric waveguide closed by two, flat end mirrors. Several short-wavelength (below 100 mu m) lines were observed. The frequencies of 28 laser lines observed in this cavity (including new lines and already known lines) were measured with a fractional uncertainty limited by the fractional resetability of the far-infrared laser cavity, of 2 parts in 10(7). C1 Univ Estadual Campinas, UNICAMP, Inst Fis Gleb Wataghin, Dept Eletron Quant, BR-13083970 Campinas, SP, Brazil. Natl Inst Stand & Technol, Div Time & Frequency, Boulder, CO 80303 USA. RP Vasconcellos, ECC (reprint author), Univ Estadual Campinas, UNICAMP, Inst Fis Gleb Wataghin, Dept Eletron Quant, BR-13083970 Campinas, SP, Brazil. RI Inst. of Physics, Gleb Wataghin/A-9780-2017 NR 4 TC 9 Z9 9 U1 1 U2 1 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 MAY PY 2000 VL 21 IS 5 BP 731 EP 737 DI 10.1023/A:1026408509524 PG 7 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA 312YE UT WOS:000086970900005 ER PT J AU Ramires, MLV de Castro, CAN Perkins, RA AF Ramires, MLV de Castro, CAN Perkins, RA TI An improved empirical correlation for the thermal conductivity of propane SO INTERNATIONAL JOURNAL OF THERMOPHYSICS LA English DT Article DE empirical correlation; n-alkane; propane; thermal conductivity; transport properties ID LIQUID PROPANE; FLUIDS; BUTANE AB New experimental data on the thermal conductivity of propane have been reported since the wide-range correlations proposed by Holland ct al. and by Younglove and fly. These new experimental data, covering a temperature range of 110 to 700 K and a pressure range of 0.1 to 70 MPa, are used together with the previously available data to develop an improved empirical equation For the thermal conductivity of gaseous and liquid propane. The quality of the new data is such that the thermal-conductivity correlation for propane is estimated to have an uncertainty of about +/-5% at a 95% confidence level, with the exception of state points near the critical point, where the uncertainty of the correlation increases to +/-10%. C1 Univ Lisbon, Fac Ciencias, Dept Quim & Bioquim, P-1700 Lisbon, Portugal. Univ Lisbon, Fac Ciencias, CiTecMat, P-1700 Lisbon, Portugal. Natl Inst Stand & Technol, Phys & Chem Properties Div, Boulder, CO 80303 USA. RP Ramires, MLV (reprint author), Univ Lisbon, Fac Ciencias, Dept Quim & Bioquim, Campo GRande,Bloco C1, P-1700 Lisbon, Portugal. RI Nieto de Castro, Carlos/B-7377-2011 OI Nieto de Castro, Carlos/0000-0001-9011-5132 NR 25 TC 3 Z9 3 U1 2 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 MAY PY 2000 VL 21 IS 3 BP 639 EP 650 DI 10.1023/A:1006685317798 PG 12 WC Thermodynamics; Chemistry, Physical; Mechanics; Physics, Applied SC Thermodynamics; Chemistry; Mechanics; Physics GA 333BH UT WOS:000088108500003 ER PT J AU Rainwater, JC AF Rainwater, JC TI A nonclassical model of a type 2 mixture with vapor-liquid, liquid-liquid, and three-phase equilibria SO INTERNATIONAL JOURNAL OF THERMOPHYSICS LA English DT Article DE carbon dioxide; critical exponents; liquid-liquid equilibria; methane; three-phase locus; Type 2 mixture; vapor liquid equilibria ID CARBON-DIOXIDE; LOW-TEMPERATURES; CRITICAL REGION; THERMODYNAMIC PROPERTIES; BINARY-MIXTURES; CRITICAL-POINTS; N-HEXANE; BEHAVIOR; SYSTEMS; METHANE AB A model with nonclassical exponents is developed for phase equilibria of a Type 2 mixture with vapor liquid equilibrium (VLE) and liquid-liquid equilibrium (LLE). Starting with a Leung-Griffiths model for a Type I mixture with only VLE, the model adds a Schofield parametric construction to describe LLE and a three-phase locus. Care is taken to suppress a spurious and artificial phase boundary. The model is applied to VLE data of ml bon dioxide + methane. It is conjectured that this mixture upon cooling would undergo liquid liquid separation, hut it freezes before such "virtual LLE" can be observed. Experimental bubble curves and the LLE structure from a classical equation of state are accurately modeled. C1 Natl Inst Stand & Technol, Phys & Chem Properties Div, Chem Sci & Technol Lab, Boulder, CO 80303 USA. RP Rainwater, JC (reprint author), Natl Inst Stand & Technol, Phys & Chem Properties Div, Chem Sci & Technol Lab, Boulder, CO 80303 USA. NR 45 TC 5 Z9 5 U1 2 U2 6 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 MAY PY 2000 VL 21 IS 3 BP 719 EP 737 DI 10.1023/A:1006645603685 PG 19 WC Thermodynamics; Chemistry, Physical; Mechanics; Physics, Applied SC Thermodynamics; Chemistry; Mechanics; Physics GA 333BH UT WOS:000088108500009 ER PT J AU Hurly, JJ Defibaugh, DR Moldover, MR AF Hurly, JJ Defibaugh, DR Moldover, MR TI Thermodynamic properties of sulfur hexafluoride SO INTERNATIONAL JOURNAL OF THERMOPHYSICS LA English DT Article DE Burnett measurements; equation of state; heat capacity; intermolecular potential; speed of sound; sulfur hexafluoride; SF6; thermodynamic properties; vapor pressure; virial coefficients ID SPEED-OF-SOUND; ACOUSTIC MEASUREMENTS; VAPOR-PRESSURES; GAS-PHASE; EQUATION; STATE; COEFFICIENTS; DENSITIES; MIXTURES; ENERGY AB We present new vapor phase speed-of-sound data u(P, T), new Burnett density pressure-temperature data p(P, T), and a few vapor pressure measurements for sulfur hexafluoride (SF6). The speed-of-sound data spanned the temperature range 230 K less than or equal to T less than or equal to 460 K and leached maximum pressures that were the lesser of 1.5 MPa or 80% of the vapor pressure of SF6. The Burnett p(P, T) data were obtained on isochores spanning the density range 137 mol.m(-3) less than or equal to P less than or equal to 4380 mol.m(-3) and the temperature range 283 K less than or equal to T less than or equal to 393 K. (The corresponding pressure range is 0.3 MPa less than or equal to P less than or equal to 9.0 MPa.) The u(P, T) data below 1.5 MPa were correlated using a model hard-core, Lennard Jones intermolecular potential for the second and third virial coefficients and a polynomial for the perfect gas heat capacity. The resulting equation of state has very high accuracy at low densities: it is: useful for calibrating mass flow controllers and may be extrapolated to 1000 K. The new u(P, T) data and the new p(P, T) data were simultaneously correlated with a virial equation of state containing four terms with the temperature dependences of model square-well potentials. This correlation extends nearly to the critical density and may help resolve contradictions among data sets From the literature. C1 Natl Inst Stand & Technol, Phys & Chem Properties Div, Chem Sci & Technol Lab, Gaithersburg, MD 20899 USA. RP Hurly, JJ (reprint author), Natl Inst Stand & Technol, Phys & Chem Properties Div, Chem Sci & Technol Lab, Gaithersburg, MD 20899 USA. RI Moldover, Michael/E-6384-2013 NR 51 TC 36 Z9 39 U1 0 U2 6 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 MAY PY 2000 VL 21 IS 3 BP 739 EP 765 DI 10.1023/A:1006697620523 PG 27 WC Thermodynamics; Chemistry, Physical; Mechanics; Physics, Applied SC Thermodynamics; Chemistry; Mechanics; Physics GA 333BH UT WOS:000088108500010 ER PT J AU Featonby, PD Savalli, V Cognet, L Helmerson, K Westbrook, N Westbrook, CI Phillips, WD Aspect, A Zabow, G Drndic, M Lee, C Westervelt, RM Prentiss, M AF Featonby, PD Savalli, V Cognet, L Helmerson, K Westbrook, N Westbrook, CI Phillips, WD Aspect, A Zabow, G Drndic, M Lee, C Westervelt, RM Prentiss, M TI Bouncing cold atom on a magnetic mirror SO JOURNAL DE PHYSIQUE IV LA French DT Article; Proceedings Paper CT 6th Colloquium on Lasers and Quantum Optics CY SEP 07-09, 1999 CL UNIV BORDEAUX I, TALENCE, FRANCE SP Soc Francaise Opt, Soc Europeenne Opt, Soc Francaise Phys, CNRS HO UNIV BORDEAUX I ID REFLECTION C1 Inst Opt, Lab Charles Fabry, UMR 8501 CNRS, F-91403 Orsay, France. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Harvard Univ, Dept Phys, Cambridge, MA 02138 USA. RP Featonby, PD (reprint author), Inst Opt, Lab Charles Fabry, UMR 8501 CNRS, 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 9 TC 1 Z9 1 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 1155-4339 J9 J PHYS IV JI J. Phys. IV PD MAY PY 2000 VL 10 IS P8 BP 139 EP 140 DI 10.1051/jp4:2000828 PG 2 WC Physics, Multidisciplinary SC Physics GA 332UW UT WOS:000088092600029 ER PT J AU Herwig, KW Fuhrmann, D Criswell, L Taub, H Hansen, FY Dimeo, R Neumann, DA AF Herwig, KW Fuhrmann, D Criswell, L Taub, H Hansen, FY Dimeo, R Neumann, DA TI Dynamics of intermediate-length alkane films absorbed on graphite SO JOURNAL DE PHYSIQUE IV LA English DT Article; Proceedings Paper CT Workshop on Dynamics in Confinement CY JAN 26-29, 2000 CL INST LAUE-LANGEVIN, GREOBLE, FRANCE SP Inst Laue Langevin HO INST LAUE-LANGEVIN AB The dynamics of flexible chain molecules near a solid interface is of fundamental interest in polymer science. This paper makes a preliminary report on a quasielastic neutron scattering study of the dynamics of monolayer films of C24H50 adsorbed on graphite. Quasielastic scattering was observed at temperatures as low as similar to 180 K, well below the monolayer melting temperature of 340 K, Preliminary analysis of the data indicates that at 230 K the entire molecule executes a rolling motion about its long axis while the terminal methyl groups exhibit relatively rapid reorientation. C1 Argonne Natl Lab, IPNS, Argonne, IL 60439 USA. NIST, Ctr Neutron Res, Gaithersburg, MD USA. RP Herwig, KW (reprint author), Argonne Natl Lab, IPNS, 9700 S Cass Ave,Bldg 360, Argonne, IL 60439 USA. RI Herwig, Kenneth/F-4787-2011 NR 5 TC 4 Z9 4 U1 0 U2 0 PU E D P SCIENCES PI LES ULIS CEDEXA PA 7, AVE DU HOGGAR, PARC D ACTIVITES COURTABOEUF, BP 112, F-91944 LES ULIS CEDEXA, FRANCE SN 1155-4339 J9 J PHYS IV JI J. Phys. IV PD MAY PY 2000 VL 10 IS P7 BP 157 EP 160 DI 10.1051/jp4:2000731 PG 4 WC Physics, Multidisciplinary SC Physics GA 332UV UT WOS:000088092500032 ER PT J AU Dimeo, RM Neumann, DA AF Dimeo, RM Neumann, DA TI Probing the dynamics of confined systems with the NIST backscattering spectrometer SO JOURNAL DE PHYSIQUE IV LA English DT Article; Proceedings Paper CT Workshop on Dynamics in Confinement CY JAN 26-29, 2000 CL INST LAUE-LANGEVIN, GRENOBLE, FRANCE SP Inst Laue Langevin HO INST LAUE-LANGEVIN ID NEUTRON-SCATTERING; ZEOLITE; GLASS AB A new high-resolution backscattering spectrometer, recently commissioned at the National Institute of Standards and Technology Center for Neutron Research is providing new opportunities in the United States for the investigation of the dynamics of condensed matter systems in confinement. The dynamic range (+/- 35 mu eV), flux at the sample position (1.4 x 10(5) n/cm(2)/s), and instrumental resolution (delta E < 1 mu eV) allow users to probe dynamics on time scales between 0.1 and 1 ns. Therefore this backscattering spectrometer is an excellent tool for probing the low energy dynamics of confined condensed matter systems. A discussion is presented of the instrument design parameters and its utility in probing dynamics in confinement is illustrated with data from recent measurements. C1 NIST, Ctr Neutron Res, Gaithersburg, MD 20899 USA. RP Dimeo, RM (reprint author), NIST, Ctr Neutron Res, 100 Bur Dr,STOP 8562, Gaithersburg, MD 20899 USA. NR 11 TC 0 Z9 0 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 1155-4339 J9 J PHYS IV JI J. Phys. IV PD MAY PY 2000 VL 10 IS P7 BP 337 EP 340 DI 10.1051/jp4:2000769 PG 4 WC Physics, Multidisciplinary SC Physics GA 332UV UT WOS:000088092500070 ER PT J AU Chung, SG Ackerman, S van Delst, PF Menzel, WP AF Chung, SG Ackerman, S van Delst, PF Menzel, WP TI Model calculations and interferometer measurements of ice-cloud characteristics SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID CIRRUS CLOUDS; RADIATIVE PROPERTIES; CLIMATE; SOUNDER AB This paper investigates the relationship between high-spectral resolution infrared (IR) radiances and the microphysical and macrophysical properties of cirrus clouds. Through use of radiosonde measurements of the atmospheric state at the Department of Energy's Atmospheric Radiation Measurement Program site, high-spectral resolution IR radiances are calculated by combining trace gas absorption optical depths from a line-by-line radiative transfer model with the discrete ordinate radiative transfer (DISORT) method. The sensitivity of the high-spectral resolution IR radiances to particle size, ice-water path, cloud-top location, cloud thickness, and multilayered cloud conditions is estimated in a multitude of calculations. DISORT calculations and interferometer measurements of cirrus ice cloud between 700 and 1300 cm(-1) are compared for three different situations. The measurements were made with the High-Spectral Resolution Interferometer Sounder mounted on a National Aeronautics and Space Administration ER-2 aircraft flying at 20-km altitude during the Subsonic Aircraft Contrail and Cloud Effects Special Study (SUCCESS). C1 NOAA, NESDIS, ORA, Madison, WI 53706 USA. Univ Wisconsin, Cooperat Inst Meteorol Satellite Studies, Madison, WI USA. RP Menzel, WP (reprint author), NOAA, NESDIS, ORA, 1225 W Dayton St, Madison, WI 53706 USA. RI Menzel, W. Paul/B-8306-2011; Ackerman, Steven/G-1640-2011 OI Menzel, W. Paul/0000-0001-5690-1201; Ackerman, Steven/0000-0002-4476-0269 NR 18 TC 27 Z9 30 U1 1 U2 3 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 MAY PY 2000 VL 39 IS 5 BP 634 EP 644 DI 10.1175/1520-0450-39.5.634 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 315LY UT WOS:000087116300004 ER PT J AU Clothiaux, EE Ackerman, TP Mace, GG Moran, KP Marchand, RT Miller, MA Martner, BE AF Clothiaux, EE Ackerman, TP Mace, GG Moran, KP Marchand, RT Miller, MA Martner, BE TI Objective determination of cloud heights and radar reflectivities using a combination of active remote sensors at the ARM CART sites SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID ATMOSPHERIC RADIATION; MICROPULSE LIDAR; PROFILING RADAR; 94-GHZ RADAR; PROGRAM; SIGNALS AB The U.S. Department of Energy's Atmospheric Radiation Measurement (ARM) Program is deploying sensitive, millimeter-wave cloud radars at its Cloud and Radiation Test Bed (CART) sites in Oklahoma, Alaska, and the tropical western pacific Ocean. The radars complement optical devices, including a Belfort or Vaisala Laser ceilometer and a micropulse lidar, in providing a comprehensive source of information on the vertical distribution of hydrometeors overhead at the sites. An algorithm is described that combines data from these active remote sensors to produce an objective determination of hydrometeor height distributions and estimates of their radar reflectivities, vertical velocities, and Doppler spectral widths, which are optimized for accuracy. These data provide fundamental information for retrieving cloud microphysical properties and assessing the radiative effects of clouds on climate. The algorithm is applied to nine months of data from the CART site in Oklahoma for initial evaluation. Much of the algorithm's calculations deal with merging and optimizing data from the radar's four sequential operating modes, which have differing advantages and limitations, including problems resulting from range sidelobes, range aliasing, and coherent averaging. Two of rile modes use advanced phase-coded pulse compression techniques to yield approximately 10 and 15 dB more sensitivity than is available from the two conventional pulse modes. Comparison of cloud-base heights from the Belfort ceilometer and the micropulse lidar confirms small biases found in earlier studies, but recent information about the ceilometer brings the agreement to within 20-30 m. Merged data of the radar's modes were found to miss approximately 5.9% of the clouds detected by the laser systems. Using data from only the radar's two less-sensitive conventional pulse modes would increase the missed detections to 22%-34%. A significant remaining problem is that the radar's lower-altitude data are often contaminated with echoes from nonhydrometeor targets, such as insects. C1 Penn State Univ, Dept Meteorol, University Pk, PA 16802 USA. Univ Utah, Dept Meteorol, Salt Lake City, UT 84112 USA. NOAA, Environm Technol Lab, Boulder, CO USA. Brookhaven Natl Lab, Div Appl Sci, Upton, NY 11973 USA. RP Clothiaux, EE (reprint author), Penn State Univ, Dept Meteorol, 503 Walker Bldg, University Pk, PA 16802 USA. NR 18 TC 293 Z9 298 U1 3 U2 26 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 MAY PY 2000 VL 39 IS 5 BP 645 EP 665 DI 10.1175/1520-0450(2000)039<0645:ODOCHA>2.0.CO;2 PG 21 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 315LY UT WOS:000087116300005 ER PT J AU McCollum, JR Gruber, A Ba, MB AF McCollum, JR Gruber, A Ba, MB TI Discrepancy between gauges and satellite estimates of rainfall in equatorial Africa SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID NASA/DAO REANALYSES; MOISTURE BUDGET; UNITED-STATES; PRECIPITATION; NCEP/NCAR; PROJECT; DATASET; CLOUD AB The Global Precipitation Climatology Project (GPCP) satellite estimates have approximately twice the magnitude of estimates produced from the rain gauges used by the GPCP in central equatorial Africa. Different possible explanations are identified and investigated. The first is that there may not be enough GPCP rain gauges in the area to provide accurate estimates of rainfall for comparisons with satellite estimates. A comparison of the time-averaged GPCP rain gauge estimate with a long-term lover 40 yr climatology indicates that the GPCP gauge estimates are similar to long-term rainfall averages, suggesting that the GPCP rain gauge analysis is not underestimating rainfall. Two other possible explanations related to the physical properties of the air masses in this region an studied. Evidence from the literature and from estimates of the effective radii of cloud droplets suggests that there may be an abundance of aerosols in central Africa, resulting in an abundance of cloud condensation nuclei, small drops, and inefficient rain processes. The second explanation is that convective clouds forming under dry conditions generally have cloud bases considerably higher than those of clouds forming in moist environments. This leads to an increase in the evaporation rate of the falling rain, resulting in less precipitation reaching the ground. Analysis of the moisture distributions from both the National Centers for Environmental Prediction numerical weather prediction model reanalysis data and the National Aeronautics and Space Administration Water Vapor Project global moisture dataset reveals that the lower troposphere in this region of Africa is relatively dry, which suggests that cloud bases are high. C1 NOAA, NESDIS, Off Res & Applicat, WWB, Camp Spring, MD 20746 USA. RP McCollum, JR (reprint author), NOAA, NESDIS, Off Res & Applicat, WWB, Room 601,5200 Auth Rd, Camp Spring, MD 20746 USA. NR 30 TC 91 Z9 92 U1 0 U2 10 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 MAY PY 2000 VL 39 IS 5 BP 666 EP 679 DI 10.1175/1520-0450-39.5.666 PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 315LY UT WOS:000087116300006 ER PT J AU Li, QH Ferraro, R Grody, N AF Li, QH Ferraro, R Grody, N TI Adequacy of using a 1/3-degree Special Sensor Microwave Imager dataset to estimate climate-scale rainfall SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article AB recently, monthly rainfall products using the National Oceanic and Atmospheric Administration National Environmental Satellite, Data, and Information Service Office of Research and Applications Special Sensor Microwave Imager (SSM/I) rainfall algorithm have been generated on a global 2.5 degrees X 2.5 degrees grid. The rainfall estimates are based on a subsampled set of the full-resolution SSM/I data, with a resulting spatial density of about one-third of what is possible at SSM/I's highest spatial resolution. The reduction in the spatial resolution was introduced in 1992 as a compromise dictated by data processing capabilities. Currently, daily SSM/I data processing at full resolution has been established and is being operated in parallel with the subsampled set. Reprocessing of the entire SSM/I time series based on the full-resolution data is plausible but requires the reprocessing of over 10 yr of retrospective data. Because the Global Precipitation Climatology Project is considering the generation of a daily 1 degrees x 1 degrees rainfall product, it is important that the effects of using the reduced spatial resolution be reexamined. In this study, error due to using the reduced-resolution versus the full-resolution SSM/I data in the gridded products at 2.5 degrees and 1 degrees grid sizes is examined. The estimates are based on statistics from radar-derived rain data and from SSM/I data taken over the Tropical Ocean and Global Atmosphere Coupled Ocean-Atmosphere Response Experiment (TOGA COARE) radar site. SSM/I data at full resolution were assumed to provide rain estimates with 12.5-km spacing. Subsampling with spacings of 25, 37.5 (which corresponds to the present situation of 1/3 degrees latitude-longitude spatial resolution). and 50 km were considered. For the instantaneous 2.5 degrees x 2.5 degrees product, the error due to subsampling, expressed as a percentage of the gridbox mean, was estimated using radar-derived data and was 6%, 10%, and 15% at these successively poorer sampling densities. For monthly averaged products on a 2.5 degrees X 2.5 degrees grid, it was substantially lower: 3%, 4%, and 7%, respectively. Subsampling errors for monthly averages on a 1 degrees X 1 degrees grid were 8%, 16%, and 23%, respectively. Estimates based on SSM/I data at full resolution gave errors that were somewhat larger than those from radar-based estimates. It was concluded that a rain product of monthly averages on a 1 degrees x 1 degrees grid must use the full-resolution SSM/I data. More work is needed to determine how applicable these estimates are to other areas of the globe with substantially different rain statistics. C1 NOAA, NESDIS, ORA, Camp Springs, MD 20746 USA. Caelum Res Corp, Silver Spring, MD USA. RP Li, QH (reprint author), NOAA, NESDIS, ORA, 5200 Auth Rd,No 703, Camp Springs, MD 20746 USA. RI Ferraro, Ralph/F-5587-2010 OI Ferraro, Ralph/0000-0002-8393-7135 NR 6 TC 2 Z9 2 U1 1 U2 1 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 MAY PY 2000 VL 39 IS 5 BP 680 EP 685 DI 10.1175/1520-0450-39.5.680 PG 6 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 315LY UT WOS:000087116300007 ER PT J AU Levine, ZH Kalukin, AR Kuhn, M Frigo, SP McNulty, I Retsch, CC Wang, YX Arp, U Lucatorto, TB Ravel, BD Tarrio, C AF Levine, ZH Kalukin, AR Kuhn, M Frigo, SP McNulty, I Retsch, CC Wang, YX Arp, U Lucatorto, TB Ravel, BD Tarrio, C TI Tomography of integrated circuit interconnect with an electromigration void SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID RECONSTRUCTION AB An integrated circuit interconnect was subject to accelerated-life test conditions to induce an electromigration void. The silicon substrate was removed, leaving only the interconnect test structure encased in silica. We imaged the sample with 1750 eV photons using the 2-ID-B scanning transmission x-ray microscope at the Advanced Photon Source, a third-generation synchrotron facility. Fourteen views through the sample were obtained over a 170 degrees range of angles (with a 40 degrees gap) about a single rotation axis. Two sampled regions were selected for three-dimensional reconstruction: one of the ragged end of a wire depleted by the void, the other of the adjacent interlevel connection (or "via"). We applied two reconstruction techniques: the simultaneous iterative reconstruction technique and a Bayesian reconstruction technique, the generalized Gaussian Markov random field method. The stated uncertainties are total, with one standard deviation, which resolved the sample to 200 +/- 70 and 140 +/- 30 nm, respectively. The tungsten via is distinguished from the aluminum wire by higher absorption. Within the void, the aluminum is entirely depleted from under the tungsten via. The reconstructed data show the applicability of this technique to three-dimensional imaging of buried defects in submicrometer structures relevant to the microelectronics industry. (C) 2000 American Institute of Physics. [S0021-8979(00)00509-0]. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Rensselaer Polytech Inst, Troy, NY 12180 USA. Intel Corp RA1 329, Hillsboro, OR 97124 USA. Argonne Natl Lab, Adv Photon Source, Argonne, IL 60439 USA. RP Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. EM zlevine@nist.gov RI Arp, Uwe/C-2854-2009; OI Arp, Uwe/0000-0002-6468-9455 NR 17 TC 22 Z9 22 U1 2 U2 3 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 MAY 1 PY 2000 VL 87 IS 9 BP 4483 EP 4488 DI 10.1063/1.373095 PN 1 PG 6 WC Physics, Applied SC Physics GA 308QJ UT WOS:000086724100068 ER PT J AU Yang, DX Chopra, HD Chen, PJ Brown, HJ Swartzendruber, LJ Egelhoff, WF AF Yang, DX Chopra, HD Chen, PJ Brown, HJ Swartzendruber, LJ Egelhoff, WF TI Magnetization reversal in polycrystalline NiO-Co exchange anisotropy coupled bilayers SO JOURNAL OF APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 44th Annual Conference on Magnetism and Magnetic Materials CY NOV 15-18, 1999 CL SAN JOSE, CALIFORNIA SP Amer Inst Phys, Magnet Soc Inst Elect & Electr Engineers, Minerals Met & Mat Soc, Amer Soc Testing & Mat, USN Off Res, Amer Ceram Soc, Amer Phys Soc ID FILMS; COERCIVITY; MODEL; BIAS AB Real time investigation of magnetization reversal in exchange anisotropy coupled polycrystalline NiO-Co bilayers show that reversal in exchange coupled Co films is highly local and nonuniform in nature. Growth of reversed domains occur primarily by the abrupt nucleation and coalescence of new reversed domains; wall motion, although observable, is not the dominant growth mode for reversed domains. Clear evidence is presented which shows that the strength of the exchange field varies at the microscopic scale across the sample. This manifests itself as different microscopic regions switching abruptly at different fields, and a given area switching at different fields in the positive and negative field directions due to the unidirectional rather than uniaxial nature of exchange anisotropy. (C) 2000 American Institute of Physics. [S0021-8979(00)60408-5]. C1 SUNY Buffalo, Dept Mech & Aerosp Engn, Mat Program, Thin Films & Nanosynth Lab, Buffalo, NY 14260 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Chopra, HD (reprint author), SUNY Buffalo, Dept Mech & Aerosp Engn, Mat Program, Thin Films & Nanosynth Lab, Buffalo, NY 14260 USA. NR 14 TC 4 Z9 4 U1 1 U2 2 PU AMER INST PHYSICS PI MELVILLE PA 2 HUNTINGTON QUADRANGLE, STE 1NO1, MELVILLE, NY 11747-4501 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD MAY 1 PY 2000 VL 87 IS 9 BP 4942 EP 4944 DI 10.1063/1.373416 PN 2 PG 3 WC Physics, Applied SC Physics GA 308RT UT WOS:000086727200091 ER EF