FN Thomson Reuters Web of Science™ VR 1.0 PT J AU Moore, B Zeidner, J AF Moore, B Zeidner, J TI The legendary ocean - The unexplored frontier SO SEA TECHNOLOGY LA English DT Article C1 NOAA, Natl Undersea Res Program, Silver Spring, MD 20910 USA. RP Moore, B (reprint author), NOAA, Natl Undersea Res Program, Silver Spring, MD 20910 USA. RI Wright, Dawn/A-4518-2011 OI Wright, Dawn/0000-0002-2997-7611 NR 0 TC 0 Z9 0 U1 0 U2 0 PU COMPASS PUBL INC PI ARLINGTON PA SUITE 1000 1117 N 19 ST, ARLINGTON, VA 22209 USA SN 0093-3651 J9 SEA TECHNOL JI Sea Technol. PD AUG PY 1999 VL 40 IS 8 BP 29 EP 34 PG 6 WC Engineering, Ocean SC Engineering GA 228QA UT WOS:000082146100004 ER PT J AU Osborn, T Foret, J Burkholder, D Menard, C AF Osborn, T Foret, J Burkholder, D Menard, C TI Coastal restoration SO SEA TECHNOLOGY LA English DT Article C1 NOAA, Silver Spring, MD 20910 USA. RP Osborn, T (reprint author), NOAA, Silver Spring, MD 20910 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU COMPASS PUBL INC PI ARLINGTON PA SUITE 1000 1117 N 19 ST, ARLINGTON, VA 22209 USA SN 0093-3651 J9 SEA TECHNOL JI Sea Technol. PD AUG PY 1999 VL 40 IS 8 BP 61 EP + PG 4 WC Engineering, Ocean SC Engineering GA 228QA UT WOS:000082146100009 ER PT J AU Reish, DJ Oshida, PS Mearns, AJ Ginn, TC Buchman, M AF Reish, DJ Oshida, PS Mearns, AJ Ginn, TC Buchman, M TI Effects of pollution on marine organisms SO WATER ENVIRONMENT RESEARCH LA English DT Review ID POLYCYCLIC AROMATIC-HYDROCARBONS; DREDGED MATERIAL DISPOSAL; VALDEZ OIL-SPILL; FUNDULUS-HETEROCLITUS LINNAEUS; DIGESTIVE FLUID EXTRACTION; TRACE-METAL CONCENTRATIONS; LUGWORM ARENICOLA-MARINA; MUSSELS MYTILUS-EDULIS; PRINCE-WILLIAM-SOUND; SAN-FRANCISCO BAY C1 Calif State Univ Long Beach, Dept Biol Sci, Long Beach, CA 90840 USA. US EPA, Washington, DC 20460 USA. NOAA, Seattle, WA 98115 USA. PTI Environm Serv, Bellevue, WA USA. RP Reish, DJ (reprint author), Calif State Univ Long Beach, Dept Biol Sci, Long Beach, CA 90840 USA. NR 181 TC 5 Z9 7 U1 2 U2 10 PU WATER ENVIRONMENT FEDERATION PI ALEXANDRIA PA 601 WYTHE ST, ALEXANDRIA, VA 22314-1994 USA SN 1061-4303 J9 WATER ENVIRON RES JI Water Environ. Res. PD AUG PY 1999 VL 71 IS 5 BP 1100 EP 1115 DI 10.2175/106143099X134009 PG 16 WC Engineering, Environmental; Environmental Sciences; Limnology; Water Resources SC Engineering; Environmental Sciences & Ecology; Marine & Freshwater Biology; Water Resources GA 230HZ UT WOS:000082246900039 ER PT J AU Cho, JW Amy, G Pellegrino, J AF Cho, JW Amy, G Pellegrino, J TI Membrane filtration of natural organic matter: Initial comparison of rejection and flux decline characteristics with ultrafiltration and nanofiltration membranes SO WATER RESEARCH LA English DT Article DE drinking water; flux decline; MWCO; nanofiltration; natural organic matter; NOM; rejection; ultrafiltration ID AQUATIC HUMIC SUBSTANCES; NOM AB Two source waters containing natural organic matter;(NOM) with different physical and chemical characteristics were crossflow-filtered using four types of membranes having different material and geometric properties. Transport measurements of NOM rejection and Aux decline were made. A resistances-in-series model was used to represent and quantitatively compare membrane flux decline and recovery. As anticipated, the resistance due to specific adsorption depended on the concentration at the membrane interface. For the two membranes showing evidence of NOM adsorption, reducing the initial flux (which we infer to also reduce the interfacial NOM concentration) also lowered the measured resistance assigned to adsorption in our protocol. Relative molecular mass (RMM) distribution measurements (by size exclusion chromatography) were used to calculate the average RMM of the NOM and persuasively illustrated that the nominal relative molecular mass cut-off(MWCO) of a membrane is not the unique predictor of rejection characteristics for NOM compounds. Size exclusion, electrostatic repulsion, and NOM aromaticity all influenced the NOM rejection. For a given wafer composition (including pH and ionic strength), membrane characteristics (such as the surface charge, hydrophobicity and nominal MWCO) can be combined with the NOM properties (such as total dissolved organic carbon, specific UV absorbance at 254 nm and humic content) to provide a consistent qualitative rationale for the transport results. Published by Elsevier Science Ltd. C1 Natl Inst Stand & Technol, Phys & Chem Properties Div, Boulder, CO 80303 USA. Univ Colorado, Boulder, CO 80309 USA. RP Pellegrino, J (reprint author), Natl Inst Stand & Technol, Phys & Chem Properties Div, MS 838-01, Boulder, CO 80303 USA. RI Cho, Jaeweon/I-4812-2014; OI PELLEGRINO, JOHN/0000-0001-7749-5003 NR 18 TC 183 Z9 189 U1 5 U2 47 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0043-1354 J9 WATER RES JI Water Res. PD AUG PY 1999 VL 33 IS 11 BP 2517 EP 2526 DI 10.1016/S0043-1354(98)00498-9 PG 10 WC Engineering, Environmental; Environmental Sciences; Water Resources SC Engineering; Environmental Sciences & Ecology; Water Resources GA 211VW UT WOS:000081183400006 ER PT J AU Zhang, JZ Fischer, CJ Ortner, PB AF Zhang, JZ Fischer, CJ Ortner, PB TI Laboratory glassware as a contaminant in silicate analysis of natural water samples SO WATER RESEARCH LA English DT Article DE silicate determination; sample storage; contamination; laboratory glassware; glass dissolution AB When glassware is used for the storage of water samples, reagents and standard solutions, dissolution of silicate from the glass containers can contaminate the samples. Experimental results demonstrate that dissolution from glassware can introduce micromolar silicate within a few hours. The extent of dissolution depends upon contact time, salinity and pH of the solution, and the size and shape of the containers. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Univ Miami, Rosenstiel Sch Marine & Atmospher Sci, CIMAS, Miami, FL 33149 USA. NOAA, Atlantic Oceanog & Meteorol Lab, Ocean Chem Div, Miami, FL 33149 USA. RP Zhang, JZ (reprint author), Univ Miami, Rosenstiel Sch Marine & Atmospher Sci, CIMAS, 4600 Rickenbacker Causeway, Miami, FL 33149 USA. RI Zhang, Jia-Zhong/B-7708-2008; Fischer, Charles/A-3843-2017 OI Zhang, Jia-Zhong/0000-0002-1138-2556; NR 7 TC 12 Z9 12 U1 0 U2 3 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0043-1354 J9 WATER RES JI Water Res. PD AUG PY 1999 VL 33 IS 12 BP 2879 EP 2883 DI 10.1016/S0043-1354(98)00508-9 PG 5 WC Engineering, Environmental; Environmental Sciences; Water Resources SC Engineering; Environmental Sciences & Ecology; Water Resources GA 226PC UT WOS:000082027500014 ER PT J AU Miller, RC Crisp, CA AF Miller, RC Crisp, CA TI The first operational tornado forecast - Twenty million to one - Prologue SO WEATHER AND FORECASTING LA English DT Article C1 USAF, Washington, DC 20330 USA. Natl Severe Storms Lab, Norman, OK 73069 USA. RP Miller, RC (reprint author), USAF, Washington, DC 20330 USA. NR 0 TC 3 Z9 3 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 1999 VL 14 IS 4 BP 479 EP 483 DI 10.1175/1520-0434(1999)014<0479:TFOTFT>2.0.CO;2 PG 5 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 228CX UT WOS:000082120300002 ER PT J AU Maddox, RA Crisp, CA AF Maddox, RA Crisp, CA TI The Tinker AFB tornadoes of March 1948 SO WEATHER AND FORECASTING LA English DT Article AB During March of 1948 Tinker Air Force Base was hit directly by two tornadoes during a period of only five days. The first tornado was the most destructive, to that point, ever to occur in Oklahoma. The second storm caused considerable additional damage and was remarkable in another, more significant, way. The first operational tornado forecast had been issued by Air Force Officers E. J. Fawbush and R. C. Miller a few hours before the tornado moved across the base. This extremely unusual meteorological situation, two tornadoes hitting the same location within five days, coupled with the fortuitous forecast of the event, had a profound impact on the evolution of operational severe weather forecasting in the United States. These events eventually stimulated the initiation of public severe by the Weather Bureau. Miller often presented anecdotal accounts of the events leading up to the landmark forecast, for example, in seminars and interviews during a visit to the National Severe Storms Laboratory during March 1994. He often stressed that the remarkable similarity of the synoptic settings on 21 and 25 March 1918 helped give him and Fawbush the courage to issue the now famous forecast. In this paper the synoptic environments that led to the two tornado occurrences at Tinker are analyzed and discussed. There were indeed similarities; however. it is surprising how different many aspects of the storm settings actually were. Similarities and important differences are illustrated with a series of synoptic surface and upper-air charts. it is likely that development of a base severe weather plan following the tornado disaster of 20 March, in addition to the presence and exhortations of General E S. Borum at the base weather station on 25 March, provided as great a motivation for the first tornado forecast as did the similarity of the synoptic settings. C1 Univ Oklahoma, CIMMS, Natl Severe Storms Lab, Norman, OK 73019 USA. RP Maddox, RA (reprint author), 529 N Pk Ave,Suite 304, Tucson, AZ 85719 USA. NR 10 TC 7 Z9 7 U1 1 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0882-8156 J9 WEATHER FORECAST JI Weather Forecast. PD AUG PY 1999 VL 14 IS 4 BP 492 EP 499 DI 10.1175/1520-0434(1999)014<0492:TTATOM>2.0.CO;2 PG 8 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 228CX UT WOS:000082120300004 ER PT J AU Miller, RC Crisp, CA AF Miller, RC Crisp, CA TI Events leading to establishment of the United States Air Force Severe Weather Warning Center in February 1951 SO WEATHER AND FORECASTING LA English DT Article C1 NOAA, Natl Severe Storms Lab, Norman, OK 73069 USA. RP Crisp, CA (reprint author), NOAA, Natl Severe Storms Lab, 1313 Halley Circle, Norman, OK 73069 USA. NR 4 TC 4 Z9 4 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 1999 VL 14 IS 4 BP 500 EP 506 DI 10.1175/1520-0434(1999)014<0500:>2.0.CO;2 PG 7 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 228CX UT WOS:000082120300005 ER PT J AU Corfidi, SE AF Corfidi, SE TI The birth and early years of the Storm Prediction Center SO WEATHER AND FORECASTING LA English DT Article ID WEATHER AB An overview of the birth and development of the National Weather Service's Storm Prediction Center, formerly known as the National Severe Storms Forecast Center, is presented. While the center's immediate history dates to the middle of the twentieth century, the nation's first centralized severe weather forecast effort actually appeared much earlier with the pioneering work of Army Signal Corps officer J. P. Finley in the 1870s. Little progress was made in the understanding or forecasting of severe convective weather after Finley until the nascent aviation industry fostered an interest in meteorology in the 1920s. Despite the increased attention, forecasts for tornadoes remained a rarity until Air Force forecasters E. J. Fawbush and R. C. Miller gained notoriety by correctly forecasting the second tornado to strike Tinker Air Force Base in one week on 25 March 1948. The success of this and later Fawbush and Miller efforts led the Weather Bureau (predecessor to the National Weather Service) to establish its own severe weather unit on a temporary basis in the Weather Bureau-Army-Navy (WBAN) Analysis Center Washington, D.C., in March 1952. The WEAN severe weather unit became a permanent, five-man operation under the direction of K. M. Barnett on 21 May 1952. The group was responsible for the issuance of "bulletins" (watches) for tornadoes, high winds, and/or damaging hail; outlooks for severe convective weather were inaugurated in January 1953. An unusually large number of strong tornadoes, forecaster inexperience, and criticism regarding the unit's products culminated in staff and policy changes after it was renamed the Severe Local Storms Warning Service (SELS) in June 1953. SELS moved from Washington to Kansas City in September 1954 in part to be closer to "tornado alley" and to take advantage of existing nationwide teletype communication facilities. The unit also gained a new leader when D. C. House replaced Barnett as SELS chief early that year. House instituted changes that led to more accurate watches. He also fostered the development of a separate research and development unit, an effort which had been initiated by Barnett. SELS continued to grow as additional forecast and support staff were added through the remainder of the 1950s and 1960s. It was renamed the National Severe Storms Forecast Center (NSSFC) upon relocation to a new facility and the assumption of local and regional forecast duties in 1966. Meanwhile, the research group to which SELS had given birth in the mid 1950s left Kansas City and merged with the Weather Bureau's Weather Radar Laboratory to form the National Severe Storms Laboratory (NSSL) in Norman, Oklahoma, in 1964. SELS, renamed the Storm Prediction Center, joined NSSL in Norman in January 1997. C1 NOAA, NWS, NCEP, Storm Predict Ctr, Norman, OK 73069 USA. RP Corfidi, SE (reprint author), NOAA, NWS, NCEP, Storm Predict Ctr, 1313 Halley Circle, Norman, OK 73069 USA. NR 62 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 1999 VL 14 IS 4 BP 507 EP 525 DI 10.1175/1520-0434(1999)014<0507:TBAEYO>2.0.CO;2 PG 19 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 228CX UT WOS:000082120300006 ER PT J AU Doswell, CA Moller, AR Brooks, HE AF Doswell, CA Moller, AR Brooks, HE TI Storm spotting and public awareness since the first tornado forecasts of 1948 SO WEATHER AND FORECASTING LA English DT Article ID UNITED-STATES; THUNDERSTORM AB The history of storm spotting and public awareness of the tornado threat is reviewed. It is shown that a downward trend in fatalities apparently began after the famous "Tri-State" tornado of 1925. Storm spotting's history begins in World War II as an effort to protect the nation's military installations, but became a public service with the resumption of public tornado forecasting. pioneered in 1948 by the Air Forse's Fawbush and Miller and begun in the public sector in 1952. The current spt,spotter program. known generally as SKYWARN, is a civilian-based volunteer organization. Responsibility for spotter training has rested with the national forecasting services (originally, the Weather Bureau and now the National Weather Service). That training has evolved with (a) the proliferation of widespread film and (recently) video footage of severe storms; (b) growth in the scientific knowledge about tornadoes and tornadic storms, as well as a better understanding of how tornadoes produce damage; and (c) the inception and growth of scientific and hobbyist storm chasing. The concept of an integrated warning System is presented in detail, and considered in light of past and present accomplishments and what needs to be done in the future to maintain the downward trend in fatalities. As the integrated warning system has evolved over its history, it has become clear that volunteer spotters and the public forecasting, services need to be closely tied. Further, public information dissemination is a major factor in an integrated warning service; warnings and forecasts that do not reach the users and produce appropriate responses are nor very valuable, even if they are accurate and timely. The history of the integration has; been somewhat checkered, but compelling evidence of the overall efficacy of the watch-warning program can be found in the maintenance of the downward trend in annual fatalities that began in 1925. C1 NOAA, Natl Severe Storms Lab, ERL, Norman, OK 73071 USA. NOAA, Natl Weather Serv, Weather Forecast Off, Ft Worth, TX USA. RP Doswell, CA (reprint author), NOAA, Natl Severe Storms Lab, ERL, Norman, OK 73071 USA. RI Doswell III, Charles/E-7662-2010 NR 23 TC 58 Z9 58 U1 4 U2 17 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 1999 VL 14 IS 4 BP 544 EP 557 DI 10.1175/1520-0434(1999)014<0544:SSAPAS>2.0.CO;2 PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 228CX UT WOS:000082120300008 ER PT J AU Kane, SF Farland, AL Siewert, TA McCowan, CN AF Kane, SF Farland, AL Siewert, TA McCowan, CN TI Welding consumable development for a cryogenic (4 K) application SO WELDING JOURNAL LA English DT Article ID TOUGHNESS AB This paper summarizes the development and qualification of an appropriate welding consumable for a demanding cryogenic magnet application. It begins With a review of the research conducted on cryogenic fracture toughness of wrought and welded austenitic stainless steels. This research shows that certain elements of the composition have a powerful effect upon the steel's fracture toughness at 4 K. In particular, the higher oxygen content in the weld manifests itself as inclusions, which have a severe detrimental effect upon the fracture toughness. This one factor accounts for most of the difference in toughness between wrought and weld materials of similar composition, and is a function of the weld process. Also, welds enriched with manganese and nickel have demonstrated improved fracture toughness. These discoveries were combined in the development of a nitrogen- and manganese-modified, high-nickel stainless-steel alloy. It produced gas metal are welds with superior cryogenic mechanical properties (yield strength near 900 MPa at 4 K and a Charpy V-notch impact energy near 140 J at 76 K) when the procedures were modified to reduce the oxygen content. C1 Brookhaven Natl Lab, Upton, NY 11973 USA. Natl Inst Stand & Technol, Boulder, CO USA. RP Kane, SF (reprint author), Brookhaven Natl Lab, Upton, NY 11973 USA. NR 21 TC 7 Z9 7 U1 0 U2 4 PU AMER WELDING SOC PI MIAMI PA PO BOX 351040, MIAMI, FL 33135 USA SN 0043-2296 J9 WELD J JI Weld. J. PD AUG PY 1999 VL 78 IS 8 BP 292S EP 300S PG 9 WC Metallurgy & Metallurgical Engineering SC Metallurgy & Metallurgical Engineering GA 223CL UT WOS:000081822400018 ER PT J AU Matrosov, SY AF Matrosov, SY TI Retrievals of vertical profiles of ice cloud microphysics from radar and IR measurements using tuned regressions between reflectivity and cloud parameters SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID CIRRUS CLOUDS; RADIOMETER MEASUREMENTS; INFRARED RADIOMETER; PARTICLE SIZES; TEMPERATURE; CLIMATE AB A new approach is suggested for retrieving vertical profiles of radiatively important microphysical parameters of ice clouds from measurements of radar reflectivity and estimates of cloud optical thickness. This approach is applicable to ground-based, vertical-mode measurements of pure ice phase clouds observed without blockage from low-liquid water clouds. It involves "tuning" the coefficient of the power law reflectivity-ice water content (Z(e)-IWC) relations for each individual profile of radar measurements. This tuning is done based on the independent estimates of cloud ice water path obtained from layer-mean values of radar reflectivity and cloud optical thickness. After a vertical profile of IWC is retrieved using this approach, a corresponding vertical profile of cloud particle median sizes, D-m, can be easily calculated for an assumed type of the particle size distribution. By assuming that the exponent in the tuned Z(e)-IWC relations changes linearly within a small dynamic range, better results are obtained compared with the case when it is assumed to be constant. The accuracy of the tuned regression approach is assessed by comparing the retrieval results for several high-quality observational cases with data from the "reference" method, which uses additional measurements of Doppler velocities. This method was verified by earlier comparisons with simultaneous in situ data. The specifics of using Doppler information, however, limit the applicability of this method and prevent its real-time applications. It is shown that the relative standard deviations of IWC and D-m retrievals using the tuned regression approach compared with the reference method are about 35% and 20%, respectively. These accuracies are much better than those that can be attained by any a priori chosen fixed regression between reflectivity and cloud microphysical parameters. At the same time, these accuracies are comparable to uncertainties of estimates of cloud parameters from direct in situ sampling. The suggested tuned regression approach is easy to implement and can be used for routine processing of ground-based, and, potentially, satellite-aircraft-based radar measurements of ice clouds. C1 Univ Colorado, NOAA, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. NOAA, Environm Technol Lab, Boulder, CO 80303 USA. RP Matrosov, SY (reprint author), R E ET6,325 Broadway, Boulder, CO 80303 USA. EM smatrosov@etl.noaa.gov NR 35 TC 43 Z9 45 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 JUL 27 PY 1999 VL 104 IS D14 BP 16741 EP 16753 DI 10.1029/1999JD900244 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 220ET UT WOS:000081652100009 ER PT J AU Daniel, JS Solomon, S Sanders, RW Portmann, RW Miller, DC Madsen, W AF Daniel, JS Solomon, S Sanders, RW Portmann, RW Miller, DC Madsen, W TI Implications for water monomer and dimer solar absorption from observations at Boulder, Colorado SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID ATMOSPHERIC ABSORPTION; CLOUD ABSORPTION; MCMURDO-STATION; AB-INITIO; RADIATION; SPECTROSCOPY; ANTARCTICA; SPECTRA; BUDGET; VAPOR AB We present ground-based spectral measurements of downward direct and diffuse solar intensities between 624 and 686 nm. Using the rising Sun as a light source, it is shown that the water dimer does not absorb significantly in this wavelength region. Over Boulder, Colorado, on July 10, 1998, the upper limit to the dimer vertical optical depth at these wavelengths is approximately 0.001, with an implied upper limit for instantaneous clear-sky absorption of solar radiation of about 0.8 W/m(2) for an overhead Sun. The direct Sun measurements also show that in the observed wavelength region no other unknown structured absorber can account for more than 0.6 W/m(2) absorption of the instantaneous downward direct solar flux for an overhead Sun. Observations of light scattered through a thick cloud reveal that when the atmosphere is saturated with respect to water vapor, no observable dimer absorption occurs and there is no significant spectral shape change in water monomer absorption at our spectral resolution. C1 NOAA, Aeron Lab, Boulder, CO 80303 USA. NOAA, Environm Technol Lab, Boulder, CO 80303 USA. Univ Colorado, NOAA, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. RP Daniel, JS (reprint author), NOAA, Aeron Lab, 325 Broadway,R E AL8, Boulder, CO 80303 USA. EM jdaniel@al.noaa.gov RI Portmann, Robert/C-4903-2009; Daniel, John/D-9324-2011 OI Portmann, Robert/0000-0002-0279-6087; NR 32 TC 44 Z9 44 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 1999 VL 104 IS D14 BP 16785 EP 16791 DI 10.1029/1999JD900220 PG 7 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 220ET UT WOS:000081652100012 ER PT J AU Sheridan, PJ Ogren, JA AF Sheridan, PJ Ogren, JA TI Observations of the vertical and regional variability of aerosol optical properties over central and eastern North America SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID UNITED-STATES; ANTHROPOGENIC AEROSOLS; SULFATE; CLIMATE; APPORTIONMENT; NEPHELOMETER; SCATTERING; PROFILES; LAYER; COAST AB Aerosol optical properties were measured in situ from a research aircraft during three recent field experiments in the central and eastern parts of North America as well as over areas of the western Atlantic Ocean. Regional and vertical variability of the aerosol properties for boundary layer and free tropospheric air were determined. In general, the differences between distributions of aerosol properties measured at low (planetary boundary layer) and high (free troposphere) altitudes were small but statistically significant at the 3% level or better. However, most of the aerosol optical thickness of the layers studied (similar to 5 km down to similar to 100 m) was encountered in the lowest 1 km of each layer. As a result, the near-surface measurements of aerosol optical properties adequately represented the portion of the lower column that dominates the radiative effects. The estimated error encountered by using near-surface aerosol measurements to calculate the layer forcing was typically <10%. C1 NOAA, Climate Monitoring & Diagnost Lab, Boulder, CO 80303 USA. RP Sheridan, PJ (reprint author), NOAA, Climate Monitoring & Diagnost Lab, 325 Broadway, Boulder, CO 80303 USA. EM psheridan@cmdl.noaa.gov RI Ogren, John/M-8255-2015 OI Ogren, John/0000-0002-7895-9583 NR 29 TC 50 Z9 51 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 1999 VL 104 IS D14 BP 16793 EP 16805 DI 10.1029/1999JD900241 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 220ET UT WOS:000081652100013 ER PT J AU Ramzi, A Bauer, BJ Scherrenberg, R Froehling, P Joosten, J Amis, EJ AF Ramzi, A Bauer, BJ Scherrenberg, R Froehling, P Joosten, J Amis, EJ TI Fatty acid modified dendrimers in bulk and solution: Single-chain neutron scattering from dendrimer core and fatty acid shell SO MACROMOLECULES LA English DT Article ID CONVERGENT-GROWTH APPROACH; CRYSTALLINE POLYETHYLENE; CASCADE POLYMERS; BUILDING-BLOCKS; MACROMOLECULES; MOLECULES; TEMPERATURE; FUNCTIONALITY; CHEMISTRY; GYRATION AB Small-angle neutron scattering (SANS) has been applied to extract the single-chain form factors of the fatty acid (FA) and the dendrimer components in bulk and dilute solution of fatty acid modified poly(propyleneimine) dendrimers (Astramol). The fatty acid chains were covalently or noncovalently linked to the end groups of two generations, G3 and G5. Bulk samples were prepared under contrast match conditions of mixtures of dendrimer-h/FAH and dendrimer-h/FAD to obtain the form factor of the fatty acid components. The solutions were prepared with deuterated fatty acid modified dendrimers in decalin solvent using the contrast match technique. Mixtures of decalin-h and decalin-cl were used to match either the dendrimer or FA components. The dendrimer core of both G3 and G5 appears collapsed, without the incorporation of a significant amount of solvent. The G3 FA portion has a size closer to that of the bulk than that of a collapsed FA shell. The G5 dendrimer has the opposite trend. C1 DSM Res, NL-6160 MD Geleen, Netherlands. Natl Inst Stand & Technol, Div Polymer, Gaithersburg, MD 20899 USA. RP Ramzi, A (reprint author), DSM Res, POB 18, NL-6160 MD Geleen, Netherlands. NR 61 TC 29 Z9 29 U1 0 U2 8 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0024-9297 J9 MACROMOLECULES JI Macromolecules PD JUL 27 PY 1999 VL 32 IS 15 BP 4983 EP 4988 DI 10.1021/ma9901238 PG 6 WC Polymer Science SC Polymer Science GA 222AE UT WOS:000081759400033 ER PT J AU Welp, KA Wool, RP Agrawal, G Satija, SK Pispas, S Mays, J AF Welp, KA Wool, RP Agrawal, G Satija, SK Pispas, S Mays, J TI Direct observation of polymer dynamics: Mobility comparison between central and end section chain segments SO MACROMOLECULES LA English DT Article ID NEUTRON REFLECTOMETRY; INITIAL-STAGES; INTERFACES; INTERDIFFUSION; DIFFUSION; REFLECTION; RELAXATION; REPTATION; LIQUIDS AB In this work the motions of chain segments in either the central 50% of a polymer or in the two end sections (25% each) were probed. Motions of the central (or end) section were measured using bilayer welding samples of deuterium-labeled polymers. Symmetric triblock poly(styrene) (HDH) was paired with fully deuterated or fully protonated poly(styrene) of nearly equal molecular weight. Changes in the deuterium profile of a given pair were directly linked to the motions of a given section of the chain. The behavior of the deuterium depth profiles was monitored using specular neutron reflectivity (SNR). Rouse and reptation model predictions for the behavior of chain segments in the end and center sections were developed using computer simulations and minor chain reptation calculations. These dynamics models are representative of two broad classes of dynamics theories: tubeless (Rouse) and tubed (reptation). These experiments were thus designed to discriminate between tubeless and tubed dynamics. Segments in the central sections showed a distinct lag in crossing the interface, while segments in the end sections crossed the interface continuously. This chain centers' lag behavior is a distinctive signature of the reptation model and is not predicted by tubeless models. These experiments offer a simple and direct observation of the highly anisotropic tube motions of entangled polymer melt chains, providing strong support for the use of reptation to describe dynamics of melt polymers at the weld interface. C1 Univ Delaware, Dept Chem Engn, Newark, DE 19716 USA. Univ Illinois, Dept Mat Sci & Engn, Urbana, IL 61801 USA. Natl Inst Stand & Technol, Ctr Neutron Res, Gaithersburg, MD 20899 USA. Univ Alabama Birmingham, Dept Chem, Birmingham, AL 35294 USA. RP Univ Delaware, Dept Chem Engn, Newark, DE 19716 USA. NR 31 TC 26 Z9 27 U1 1 U2 8 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 JUL 27 PY 1999 VL 32 IS 15 BP 5127 EP 5138 DI 10.1021/ma990196r PG 12 WC Polymer Science SC Polymer Science GA 222AE UT WOS:000081759400047 ER PT J AU Ratliff, LP Minniti, R Bard, A Bell, EW Gillaspy, JD Parks, D Black, AJ Whitesides, GM AF Ratliff, LP Minniti, R Bard, A Bell, EW Gillaspy, JD Parks, D Black, AJ Whitesides, GM TI Exposure of self-assembled monolayers to highly charged ions and metastable atoms SO APPLIED PHYSICS LETTERS LA English DT Article ID ENERGY-LOSS; SLOW; LITHOGRAPHY; SILICON; HELIUM; SOLIDS; BEAMS AB The doses of neutral metastable argon atoms (Ar*) and highly charged xenon ions (HCIs) required to damage self-assembled monolayers (SAMs) of alkanethiolates on gold are compared in a set of experiments carried out concurrently. The extent of damage to the SAM is determined by developing the samples in a gold etching solution, then measuring the decrease in reflectivity of the gold; approximate to 10(5) Ar* are required to cause the same amount of damage as 1 HCI, as measured by this assay. We have also demonstrated HCI micropatterning of a surface using a physical mask, suggesting the application of this system in lithography. (C) 1999 American Institute of Physics. [S0003-6951(99)03330-6]. C1 Natl Inst Stand & Technol, Atom Phys Div, Gaithersburg, MD 20899 USA. Harvard Univ, Dept Chem & Biol Chem, Cambridge, MA 02138 USA. RP Bell, EW (reprint author), Natl Inst Stand & Technol, Atom Phys Div, Gaithersburg, MD 20899 USA. NR 18 TC 24 Z9 24 U1 1 U2 4 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD JUL 26 PY 1999 VL 75 IS 4 BP 590 EP 592 DI 10.1063/1.124451 PG 3 WC Physics, Applied SC Physics GA 218UK UT WOS:000081570400052 ER PT J AU Kim, YJ Aharony, A Birgeneau, RJ Chou, FC Entin-Wohlman, O Erwin, RW Greven, M Harris, AB Kastner, MA Korenblit, IY Lee, YS Shirane, G AF Kim, YJ Aharony, A Birgeneau, RJ Chou, FC Entin-Wohlman, O Erwin, RW Greven, M Harris, AB Kastner, MA Korenblit, IY Lee, YS Shirane, G TI Ordering due to quantum fluctuations in Sr2Cu3O4Cl2 SO PHYSICAL REVIEW LETTERS LA English DT Article ID LATTICE HEISENBERG-ANTIFERROMAGNET; SPIN; SCATTERING; DISORDER AB Sr2Cu3O4Cl2 has Cu-I and Cu-II subsystems, forming interpenetrating S=1/2 square lattice Heisenberg antiferromagnets. The classical ground state is degenerate, due to frustration of the intersubsystem interactions. Magnetic neutron scattering experiments show that quantum fluctuations cause a two dimensional Ising ordering of the Cu-II's, lifting the degeneracy, and a dramatic increase of the Cu-I out-of-plane spin-wave gap, unique for order out of disorder. The spin-wave energies are quantitatively predicted by calculations which include quantum fluctuations. C1 MIT, Ctr Mat Sci & Engn, Cambridge, MA 02139 USA. Harvard Univ, Div Engn & Appl Sci, Cambridge, MA 02138 USA. Tel Aviv Univ, Sch Phys & Astron, IL-69978 Tel Aviv, Israel. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Univ Penn, Dept Phys, Philadelphia, PA 19104 USA. Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. RP Kim, YJ (reprint author), MIT, Ctr Mat Sci & Engn, Cambridge, MA 02139 USA. RI Kim, Young-June /G-7196-2011; ENTIN, ORA/F-1114-2012; harris, A Brooks/C-8640-2013 OI Kim, Young-June /0000-0002-1172-8895; NR 22 TC 54 Z9 54 U1 0 U2 8 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 26 PY 1999 VL 83 IS 4 BP 852 EP 855 DI 10.1103/PhysRevLett.83.852 PG 4 WC Physics, Multidisciplinary SC Physics GA 219KK UT WOS:000081606300049 ER PT J AU Ridge, KD Ngo, T Lee, SSJ Abdulaev, NG AF Ridge, KD Ngo, T Lee, SSJ Abdulaev, NG TI Folding and assembly in rhodopsin - Effect of mutations in the sixth transmembrane helm on the conformation of the third cytoplasmic loop SO JOURNAL OF BIOLOGICAL CHEMISTRY LA English DT Article ID LIGHT-STABLE RHODOPSIN; BOVINE RHODOPSIN; MONOCLONAL-ANTIBODIES; POLYPEPTIDE FRAGMENTS; MEMBRANE; EXPRESSION; PROTEINS; GENE; CHROMOPHORE; SEQUENCE AB Previous studies on bovine opsin folding and assembly have identified an amino-terminal fragment, EF(1-232), which folds and inserts into a membrane only after coexpression with its complementary carboxyl-terminal fragment, EF(233-348), To further characterize this interaction, EF(1-232) production was examined upon coexpression with carboxyl-terminal fragments of varying length and/or amino acid composition. These included fragments with incremental deletions of the third cytoplasmic loop (TH(241-348) and EF(249-348)), a fragment composed of the third cytoplasmic loop and sixth transmembrane helix (HF(233-280)), a fragment composed of the sixth and seventh transmembrane helices (FG(249-312)), and EF(233-348) and TH(241-348) fragments with Pro-267 or Trp-265 mutations. Although EF(1-232) production was independent of the third cytoplasmic loop and carboxyl-terminal tail, both the sixth and seventh transmembrane helices were essential. The effects of mutations in the sixth transmembrane helix on EF(1-232) expression were dependent on the length of the third cytoplasmic loop. Although Pro-267 mutations in EF(233-348) failed to stabilize EF(1-232) expression, their introduction into TH(241-348) was without discernible effects. However, Trp-265 substitutions in the EF(233-348) and TH(241-348) fragments conferred significant EF(1-232) production. Therefore, key residues in the transmembrane helices may exert their effects on opsin folding, assembly, and/or function by influencing the conformation of the connecting loops. C1 NIST, Ctr Adv Res Biotechnol, Rockville, MD 20850 USA. Univ Maryland, Maryland Biotechnol Inst, Rockville, MD 20850 USA. RP Ridge, KD (reprint author), NIST, Ctr Adv Res Biotechnol, Rockville, MD 20850 USA. FU NEI NIH HHS [EY11112] NR 37 TC 11 Z9 11 U1 0 U2 0 PU AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3996 USA SN 0021-9258 J9 J BIOL CHEM JI J. Biol. Chem. PD JUL 23 PY 1999 VL 274 IS 30 BP 21437 EP 21442 DI 10.1074/jbc.274.30.21437 PG 6 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 219NJ UT WOS:000081613100098 PM 10409707 ER PT J AU Slusher, JT AF Slusher, JT TI Accurate estimates of infinite-dilution chemical potentials of small hydrocarbons in water via molecular dynamics simulation SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article ID SOLVATION FREE-ENERGIES; CHARGING-INTEGRAL APPROACH; GIBBS FREE-ENERGY; COMPUTER-SIMULATION; HYDROPHOBIC HYDRATION; ACTIVITY-COEFFICIENTS; METHANE; PERTURBATION; MIXTURES; ETHANE AB The infinite dilution chemical potentials of methane, ethane, propane, and benzene in water are precisely estimated using the single charging integral method [Chialvo, J. Chem. Phys. 1990, 92, 673; Chialvo, J. Phys. Chem. 1991, 95, 6683] in conjunction with molecular dynamics (MD) simulation using simple pair potentials. The method requires the calculation of ensemble averages of derivatives of the potential energy with respect to the model parameters. The derivatives take the form of pairwise virials and energies which are easily obtained with minor modifications to an existing MD code. The present approach is found to be both stable and precise and allows individual contributions of the model parameters to the free energies to be determined. The dependence of the results for the benzene system on the size of the system is investigated, as is the sensitivity of all of the results to the Lorentz-Berthelot combining rules. The importance of including long-ranged corrections in the results is highlighted. The computed chemical potentials for the united atom hydrocarbon models agree with experiment to within 0.7 kJ/mol. C1 Natl Inst Stand & Technol, Phys & Chem Properties Div, Gaithersburg, MD 20899 USA. RP Slusher, JT (reprint author), Lockheed Martin Corp, 3201 Jermantown Rd, Fairfax, VA 22030 USA. NR 32 TC 15 Z9 15 U1 2 U2 5 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 22 PY 1999 VL 103 IS 29 BP 6075 EP 6079 DI 10.1021/jp990709w PG 5 WC Chemistry, Physical SC Chemistry GA 222CM UT WOS:000081765900024 ER PT J AU Zhao, YZ AF Zhao, YZ TI Signal-induced fluorescence in photomultipliers in differential absorption lidar systems SO APPLIED OPTICS LA English DT Article ID GAIN AB Signal-induced bias (SIB) superimposed on the tail of lidar signals detected by photomultiplier tubes (PMT's) has long been recognized as significant interference in lidar data retrieval. Analysis of the data from a lidar transmitting in the horizontal direction revealed that SIE is a well-shaped pulse and is thus called a signal-induced pulse (SIP). The SIP starts near the end of the signal and has an exponentially decaying tail. The decay time constant is negatively correlated with the pulse rise time. The origins of afterpulses discussed in the literature could not explain the cause of the SIP. This research leads to the hypothesis that the SIP is the fluorescence emitted from the PMT wall that is impinged by ions in the PMT. A model was developed, and the results show good agreement with the data. This model is applied to remove SIP's during processing of data from an ozone-profiling lidar. (C) 1999 Optical Society of America. C1 Univ Colorado, NOAA, Cooperat Inst Res Environm Sci, Boulder, CO 80303 USA. RP Zhao, YZ (reprint author), Univ Colorado, NOAA, Cooperat Inst Res Environm Sci, Mail Stop R-E-ET2,325 Broadway, Boulder, CO 80303 USA. EM yzhao@etl.noaa.gov NR 21 TC 19 Z9 21 U1 1 U2 5 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1559-128X EI 2155-3165 J9 APPL OPTICS JI Appl. Optics PD JUL 20 PY 1999 VL 38 IS 21 BP 4639 EP 4648 DI 10.1364/AO.38.004639 PG 10 WC Optics SC Optics GA 220MX UT WOS:000081670700025 PM 18323951 ER PT J AU Senturker, S Bauche, C Laval, J Dizdaroglu, M AF Senturker, S Bauche, C Laval, J Dizdaroglu, M TI Substrate specificity of Deinococcus radiodurans Fpg protein SO BIOCHEMISTRY LA English DT Article ID GENERATED FREE-RADICALS; OXIDATIVE DNA-DAMAGE; SACCHAROMYCES-CEREVISIAE; IONIZING-RADIATION; PURINE LESIONS; EXCISION; GLYCOSYLASE; 8-OXOGUANINE; REPAIR; BASES AB A DNA repair enzyme has recently been isolated from the ionizing radiation-resistant bacterium Deinococcus radiodurans [Bauche, C., and Laval, J. (1999) J. Bacteriol. 181, 262-269]. This enzyme is a homologue of the Fpg protein of Escherichia coli. We investigated the substrate specificity of this enzyme for products of oxidative DNA base damage using gas chromatography/isotope-dilution mass spectrometry and DNA substrates, which were either gamma-irradiated or treated with H2O2/Fe(III)-EDTA/ascorbic acid. Excision of purine lesions 2,6-diamino-4-hydroxy-5-formamidopyrimidine (FapyGua), 4,6-diamino-5-formamidopyrimidine (FapyAde), and 8-hydroxyguanine (8-OH-Gua) was observed among 17 lesions detected in damaged DNA substrates. The extent of excision was determined as a function of enzyme concentration, time, and substrate concentration. FapyGua and FapyAde were excised with similar specificities from three DNA substrates, whereas 8-OH-Gua was the least preferred lesion. The results show that D. radiodurans Fpg protein and its homologue E. coli Fpg protein excise the same modified DNA bases, but the excision rates of these enzymes are significantly different. Formamidopyrimidines are preferred substrates of D. radiodurans Fpg protein over 8-OH-Gua, whereas E. coli Fpg protein excises these three lesions with similar efficiencies from various DNA substrates. Substrate specificities of these enzymes were also compared with that of Saccharomyces cerevisiae Ogg1 protein, which excises FapyGua and 8-OH-Gua, but not FapyAde. C1 Natl Inst Stand & Technol, Chem Sci & Technol Lab, Gaithersburg, MD 20899 USA. Inst Gustave Roussy, CNRS, UMR 8532, F-98405 Villejuif, France. RP Dizdaroglu, M (reprint author), Natl Inst Stand & Technol, Chem Sci & Technol Lab, 100 Bur Dr,Stop 8311, Gaithersburg, MD 20899 USA. NR 23 TC 25 Z9 25 U1 0 U2 1 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0006-2960 J9 BIOCHEMISTRY-US JI Biochemistry PD JUL 20 PY 1999 VL 38 IS 29 BP 9435 EP 9439 DI 10.1021/bi990680m PG 5 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 219PQ UT WOS:000081616000028 PM 10413519 ER PT J AU Frost, GJ Trainer, M Mauldin, RL Eisele, FL Prevot, ASH Flocke, SJ Madronich, S Kok, G Schillawski, RD Baumgardner, D Bradshaw, J AF Frost, GJ Trainer, M Mauldin, RL Eisele, FL Prevot, ASH Flocke, SJ Madronich, S Kok, G Schillawski, RD Baumgardner, D Bradshaw, J TI Photochemical modeling of OH levels during the first aerosol characterization experiment (ACE 1) SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID PHOTOSTATIONARY STATE; RADIOMETER MEASUREMENTS; OZONE PRODUCTION; PEROXY-RADICALS; HO2 RADICALS; CLOUDS; PHOTODISSOCIATION; ATMOSPHERE; CHEMISTRY; PHOTOLYSIS AB measurements of hydroxyl radical concentrations, [OH], in the lower free troposphere and marine boundary layer, taken during the First Aerosol Characterization Experiment (ACE 1). This paper describes in more detail the modeling results and the model-measurement comparisons which were presented by Mauldin et nl. [1997, 1998]. Modeled and observed [OH] agree to within the combined uncertainties, with a median model overestimate of 32%. The model quantifies the sources and sinks of OH for low levels of nitric oxide (NO). Predicted concentrations of the peroxy radicals HO2 and CH3O2 and total radical production and Toss rates from these model calculations are presented. Sensitivities to model input parameters and the uncertainty each contributes to the calculated [OH] are discussed. Model overpredictions of observed [OH] within clouds can be corrected by including a loss of gas phase OH to cloud droplets. The low [NO] conditions preclude HO2:! uptake alone from explaining observed depletions of OH within clouds. We examined the dependence of gas phase [OH] on its assumed mass accommodation coefficient, which the measurements suggest is 0.1 or greater for the cloud droplets encountered in ACE 1. C1 NOAA, Aeron Lab, Boulder, CO 80303 USA. Natl Ctr Atmospher Res, Atmospher Technol Div, Boulder, CO 80307 USA. Natl Ctr Atmospher Res, Div Atmospher Chem, Boulder, CO 80307 USA. Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. Georgia Inst Technol, Georgia Tech Res Inst, Environm & Mat Lab, Atlanta, GA 30332 USA. Georgia Inst Technol, Sch Earth & Atmospher Sci, Atlanta, GA 30332 USA. RP Frost, GJ (reprint author), NOAA, Aeron Lab, 325 Broadway, Boulder, CO 80303 USA. EM gfrost@al.noaa.gov RI Prevot, Andre/C-6677-2008; Trainer, Michael/H-5168-2013; Frost, Gregory/I-1958-2013; Madronich, Sasha/D-3284-2015 OI Prevot, Andre/0000-0002-9243-8194; Madronich, Sasha/0000-0003-0983-1313 NR 40 TC 26 Z9 28 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 20 PY 1999 VL 104 IS D13 BP 16041 EP 16052 DI 10.1029/1999JD900171 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 218CE UT WOS:000081535000013 ER PT J AU Zhang, YP Kreidenweis, SM Feingold, G AF Zhang, YP Kreidenweis, SM Feingold, G TI Stratocumulus processing of gases and cloud condensation nuclei 2. Chemistry sensitivity analysis SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID MARINE BOUNDARY-LAYER; CHEMICAL-COMPOSITION; STRATIFORM CLOUDS; HYDROGEN-PEROXIDE; AQUEOUS-SOLUTIONS; DROPLETS; WATER; COEFFICIENT AB A trajectory ensemble model (TEM) is used to investigate aqueous processing of gases and cloud condensation nuclei (CCN) in the boundary layer. The coupled aqueous chemistry/cloud microphysics model driven by a set of boundary layer parcel trajectories derived from a large eddy simulation is used to study the effects of variations in the initial chemical fields and initial aerosol number concentration on chemical heterogeneity, and the broadening of CCN and drop spectra. The differences in the overall fractional conversion between the TEM and a single parcel experiencing mean conditions in a stratocumulus-capped marine boundary layer are also investigated. Results show that the O-3 oxidation rate is larger than the H2O2 oxidation rate in the base case, whereas the volume-mean pH might suggest that H2O2 oxidation dominates. Aqueous chemistry contributes to broadening of the drop size distribution, but the magnitude of the broadening also depends on initial chemical conditions. Sensitivity tests show that the H2O2 oxidation adds sulfate mass evenly and continuously across the particle sizes, while the O-3 oxidation adds sulfate mass near the mode of the CCN spectrum over a relatively short time. In cases where more mass is added onto large particles in the tail of the initial CCN spectrum, the broadening of the drop spectrum is most evident, and may even trigger the collision-coalescence process and drizzle formation in stratocumulus clouds. C1 Colorado State Univ, Dept Atmospher Sci, Ft Collins, CO 80523 USA. NOAA, Environm Res Lab, Cooperat Inst Res Atmosphere, Boulder, CO 80303 USA. RP Zhang, YP (reprint author), Natl Ctr Atmospher Res, CGD, Climate Modeling Sect, POB 3000, Boulder, CO 80307 USA. EM soniak@aerosol.atmos.colostate.edu RI Feingold, Graham/B-6152-2009; Kreidenweis, Sonia/E-5993-2011 OI Kreidenweis, Sonia/0000-0002-2561-2914 NR 38 TC 19 Z9 19 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 20 PY 1999 VL 104 IS D13 BP 16061 EP 16080 DI 10.1029/1999JD900206 PG 20 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 218CE UT WOS:000081535000015 ER PT J AU Stith, J Dye, J Ridley, B Laroche, P Defer, E Baumann, K Hubler, G Zerr, R Venticinque, M AF Stith, J Dye, J Ridley, B Laroche, P Defer, E Baumann, K Hubler, G Zerr, R Venticinque, M TI NO signatures from lightning flashes SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID NITRIC-OXIDE PRODUCTION; DISCHARGES; REGIONS AB In situ measurements of cloud properties, NQ, and other trace gases were made in active thunderstorms by two research aircraft. Concurrent measurements from a three-dimensional (3-D) VHF interferometer and the 2-D National Lightning Detection Network were used to determine lightning frequency and location. The CHILL Doppler radar and the NOAA-WP-3D Orion X band Dopper radar were also used to measure storm characteristics. Two case studies from the (STERAO) Stratosphere-Troposphere Experiments: Radiation, Aerosols, and Ozone project in northeastern Colorado during the summer of 1996 are presented. Narrow spikes (0.11-0.96 km across), containing up to 19 ppbv of NO, were observed in the storms. Most were located in or downwind of electrically active regions where the NO produced by lightning would be expected. However, it was difficult to correlate individual flashes with NO spikes. A simple model of the plume of NO from lightning is used to estimate NO production from the mean mixing ratio measured in these spikes. The estimates range from 2.0 x 10(20) to 1.0 x 10(22) molecules of NO per meter of flash length. C1 Univ N Dakota, Dept Atmospher Sci, Grand Forks, ND 58202 USA. Georgia Inst Technol, Sch Earth & Atmospher Sci, Atlanta, GA 30332 USA. Off Natl Etud & Rech Aerosp, F-92322 Chatillon, France. Natl Ctr Atmospher Res, Boulder, CO 80307 USA. NOAA, Aeron Lab, Boulder, CO 80303 USA. RP Stith, J (reprint author), Univ N Dakota, Dept Atmospher Sci, Box 9006,Univ Stn, Grand Forks, ND 58202 USA. EM Stith@aero.und.edu RI Hubler, Gerhard/E-9780-2010 NR 17 TC 48 Z9 49 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUL 20 PY 1999 VL 104 IS D13 BP 16081 EP 16089 DI 10.1029/1999JD900174 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 218CE UT WOS:000081535000016 ER PT J AU Jobson, BT McKeen, SA Parrish, DD Fehsenfeld, FC Blake, DR Goldstein, AH Schauffler, SM Elkins, JC AF Jobson, BT McKeen, SA Parrish, DD Fehsenfeld, FC Blake, DR Goldstein, AH Schauffler, SM Elkins, JC TI Trace gas mixing ratio variability versus lifetime in the troposphere and stratosphere: Observations SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID POLAR SUNRISE EXPERIMENT; PEM-WEST-B; LAYER OZONE DEPLETION; SOUTH-ATLANTIC OCEAN; CHEMICAL CHARACTERISTICS; PACIFIC-OCEAN; CONTINENTAL OUTFLOW; TRAJECTORY HISTORY; LIGHT-HYDROCARBONS; OH CONCENTRATIONS AB Several archived data sets have been reviewed to examine the relationship between mixing ratio variability and lifetime for hydrocarbon and halocarbon species in the troposphere and stratosphere. The dependence on lifetime was described by the power law relationship s(lnx) = A tau(-b), where slnx is the standard deviation of the In of the mixing ratios, A is a proportionality coefficient, and b is an exponent that relates to the dominance of sink terms in the regional variability budget. At the Harvard forest ground site, winter and summer data displayed the same lifetime dependence, tau(-0.18), which was significantly weaker than the tau(-0.5) dependence of remote tropospheric data, indicating that source terms dominated regional variability at Harvard. In addition, the ratio of summer to winter slnx values was found to be similar for all species except ethane, averaging 1.54 +/- 0.04. This ratio is consistent with a factor of Ii seasonal change in the species lifetimes, given a tau(-0.18) ls lifetime dependence. Stratospheric data displayed a stronger lifetime dependence than tropospheric trends, indicating a more dominant role for sink terms in describing spatial variability in this region of the atmosphere. We show that a unique power law relationship between s(lnX) ratios for two species X-i and X-j and the kinetic slope of In(X-i) versus In(X-i) correlation plots is found to hold in both observations and theory. Thus knowledge of tl coefficient b allows for a clearer understanding of the relationship between observed slopes of In(X-i) versus In(X-i) correlation plots and the ratio of the species lifetimes. C1 Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80303 USA. NOAA, Aeron Lab, Boulder, CO 80303 USA. NOAA, Climate Monitoring & Diagnost Lab, Boulder, CO 80303 USA. Univ Calif Berkeley, ESPM Ecosyst Sci Div, Berkeley, CA 94720 USA. Natl Ctr Atmospher Res, Boulder, CO 80307 USA. Univ Calif Irvine, Dept Chem, Irvine, CA 92717 USA. RP Jobson, BT (reprint author), Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80303 USA. EM tjobson@al.noaa.gov RI Parrish, David/E-8957-2010; Goldstein, Allen/A-6857-2011; McKeen, Stuart/H-9516-2013; Fehsenfeld, Frederick/I-4876-2013; OI Parrish, David/0000-0001-6312-2724; Goldstein, Allen/0000-0003-4014-4896; Jobson, Bertram/0000-0003-1812-9745 NR 61 TC 51 Z9 54 U1 3 U2 17 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUL 20 PY 1999 VL 104 IS D13 BP 16091 EP 16113 DI 10.1029/1999JD900126 PG 23 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 218CE UT WOS:000081535000017 ER PT J AU Smyth, S Sandholm, S Shumaker, B Mitch, W Kanvinde, A Bradshaw, J Liu, S McKeen, S Gregory, G Anderson, B Talbot, R Blake, D Rowland, S Browell, E Fenn, M Merrill, J Bachmeier, S Sachse, G Collins, J AF Smyth, S Sandholm, S Shumaker, B Mitch, W Kanvinde, A Bradshaw, J Liu, S McKeen, S Gregory, G Anderson, B Talbot, R Blake, D Rowland, S Browell, E Fenn, M Merrill, J Bachmeier, S Sachse, G Collins, J TI Characterization of the chemical signatures of air masses observed during the PEM experiments over the western Pacific SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID CONTINENTAL OUTFLOW; TRACER MODEL; AEROSOLS; PHASE AB Extensive observations of tropospheric trace species during the second NASA Global Tropospheric Experiment Western Pacific Exploratory Mission (PEM-West B) in February-March 1994 showed significant seasonal variability in comparison with the first mission (PEM-West A), conducted in September-October 1991. In this study we adopt a previously established analytical method, i.e., the ratio C2H2/CO as a measure of the relative degree of atmospheric processing, to elucidate the key similarities and variations between the two missions, In addition, the C2H2/CO ratio scheme is combined with the back-trajectory-based and the LIDAR-based air mass classification schemes, respectively, to make in-depth analysis of the seasonal variation between PEM-West A and PEM-West B (hereinafter referred to as PEM-WA and PEM-WB). A large number of compounds, including long-lived NMHCs, CH4, and CO2, are, as expected, well correlated with the ratio C2H2/CO. In comparison with PEM-WA, a significantly larger range of observed C2H2/CO values at the high end for the PEM-WB period indicates that the western Pacific was more impacted by "fresher" source emissions, i.e., faster or mote efficient continental outflow. As in the case of PEM-WA, the C2H2/CO scheme complements the back-trajectory air mass classification scheme very well. By combining the two schemes, we found that the atmospheric processing in the region is dominated by atmospheric mixing for the trace species analyzed. This PEM-WB wintertime result is similar to that found in PEM-WA for the autumn. In both cases, photochemical reactions are found to play a significant role in determining the background mixing ratios of trace gases, and in this way the two processes are directly related and dependent upon each other. This analysis also indicates that many of the upper tropospheric air masses encountered over the western Pacific during PEM-WB may have had little impact from eastern Asia's continental surface sources. NOx mixing ratios were significantly enhanced during PEM-WB when compared with PEM-WA, in the upper troposphere's more atmospherically processed air masses. These high levels of NOx resulted in a substantial amount of photochemical production of O-3. A lack of corresponding enhancements in surface emission tracers strongly implies that in situ atmospheric sources such as lightning are responsible for the enhanced upper tropospheric NOx. The similarity in NOx values between the northern (higher air traffic) and southern continental air masses together with the indications of a large seasonal shift suggests that aircraft emissions are not the dominant source. However, photochemical recycling cannot be ruled out as this in situ source of NOx. C1 Georgia Inst Technol, Sch Earth & Atmospher Sci, Atlanta, GA 30332 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. Univ Calif Irvine, Dept Chem, Irvine, CA 92717 USA. NOAA, Aeron Lab, Boulder, CO 80303 USA. Univ Rhode Isl, Grad Sch Oceanog, Ctr Atmospher Chem Studies, Narragansett, RI 02882 USA. Univ New Hampshire, Inst Study Earth Oceans & Space, Durham, NH 03820 USA. RP Smyth, S (reprint author), Georgia Inst Technol, Sch Earth & Atmospher Sci, Atlanta, GA 30332 USA. RI McKeen, Stuart/H-9516-2013 NR 25 TC 19 Z9 19 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUL 20 PY 1999 VL 104 IS D13 BP 16243 EP 16254 DI 10.1029/1999JD900115 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 218CE UT WOS:000081535000026 ER PT J AU Bacmeister, JT Kuell, V Offermann, D Riese, M Elkins, JW AF Bacmeister, JT Kuell, V Offermann, D Riese, M Elkins, JW TI Intercomparison of satellite and aircraft observations of ozone, CFC-11, and NOy using trajectory mapping SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID ER-2 AIRCRAFT; INSTRUMENTS ABOARD; ARCTIC WINTER; STRATOSPHERE; ASHOE/MAESA; TRANSPORT; ATMOS AB The Cryogenic Infrared Spectrometers and Telescopes for the Atmosphere (CRISTA) satellite measured global distributions of over 15 trace constituents at high horizontal resolution (<500 km), The CRISTA mission began shortly before the end of the Airborne Southern Hemisphere Ozone Experiment and Measurements to Assess the Effects of Stratospheric Aircraft (ASHOE/MAESA) airborne measurement campaign. CRISTA measurements of ozone, CFC-11, and HNO3 are available below 20 km, in the altitude range sampled by the ER-2 aircraft during ASHOE/MAESA. However, the time separation between the two missions makes a direct comparison of the data impossible. In this study, trajectory techniques are used to compare CRISTA measurements of ozone, CFC-11, and HNO3 with ER-2 measurements taken during the last two flights of ASHOE/MAESA on November 2 and 4, 1994. Visual comparison of CRISTA and ER-2 data from the November 4 flight is generally good. Mean tracer gradients across scales of similar to 1000 km, as well as absolute mixing ratios agree well with those measured from the ER-2, Correlation coefficients for coincident pairs of ER-2 and CRISTA measurements are between 0.68 and 0.80. The comparison for the November 2 flight is poor. We argue that the poor agreement for this flight maybe due to both smaller CRISTA measurement density as well as rapid stretching in the air mass sampled by the ER-2 on November 2. C1 NOAA, Climate Monitoring & Diagnost Lab, Boulder, CO 80303 USA. Berg Univ Wuppertal, Dept Phys, D-42097 Wuppertal, Germany. USN, Res Lab, Washington, DC 20375 USA. RP Bacmeister, JT (reprint author), NASA, Goddard Space Flight Ctr, Mail Code 913, Greenbelt, MD 20771 USA. EM bacmj@janus.gsfc.nasa.gov RI Riese, Martin/A-3927-2013 OI Riese, Martin/0000-0001-6398-6493 NR 26 TC 16 Z9 16 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 20 PY 1999 VL 104 IS D13 BP 16379 EP 16390 DI 10.1029/1999JD900173 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 218CE UT WOS:000081535000035 ER PT J AU Plant, AL AF Plant, AL TI Supported hybrid bilayer membranes as rugged cell membrane mimics SO LANGMUIR LA English DT Article ID SELF-ASSEMBLED MONOLAYERS; SURFACE-PLASMON RESONANCE; LIPID BILAYERS; ALKANETHIOL MONOLAYERS; PROTON TRANSLOCATION; ELECTRON-TRANSFER; GOLD SURFACES; CYTOCHROME-C; SPECTROSCOPY; VESICLES AB Supported planar lipid bilayers based on alkanethiol-tethering chemistry are becoming increasingly important biomimetic materials. Hybrid bilayers containing thiol-derivatized alkane moieties plus natural Lipids provide a biomimetic matrix that permits the successful reconstitution of membrane protein activity. The hybrid membrane is self-assembled and sufficiently rugged to be of practical use in research and in commercial sensing applications. The coupling of the bilayer to a metal support allows a wide range of analytical techniques to be applied to this model membrane. This article reviews some of the fundamental studies of the formation, structure, and response of hybrid bilayer membranes. C1 Natl Inst Stand & Technol, Div Biotechnol, Gaithersburg, MD 20899 USA. RP Plant, AL (reprint author), Natl Inst Stand & Technol, Div Biotechnol, Gaithersburg, MD 20899 USA. NR 41 TC 247 Z9 252 U1 5 U2 65 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0743-7463 J9 LANGMUIR JI Langmuir PD JUL 20 PY 1999 VL 15 IS 15 BP 5128 EP 5135 DI 10.1021/la981662t PG 8 WC Chemistry, Multidisciplinary; Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA 219ZD UT WOS:000081637800030 ER PT J AU Graneli, E Carlsson, P Turner, JT Tester, PA Bechemin, C Dawson, R Funari, E AF Graneli, E Carlsson, P Turner, JT Tester, PA Bechemin, C Dawson, R Funari, E TI Effects of N : P : Si ratios and zooplankton grazing on phytoplankton communities in the northern Adriatic Sea. I. Nutrients, phytoplankton biomass, and polysaccharide production SO AQUATIC MICROBIAL ECOLOGY LA English DT Article DE Adriatic Sea; nitrogen; silicon; limitation; phytoplankton; phosphorus; polysaccharide; chemical composition ID FRESH-WATER; MARINE ENVIRONMENTS; PHOSPHORUS; LIMITATION; EUTROPHICATION; NITROGEN; CULTURE; ECOLOGY; CELLS AB The northern Adriatic Sea has been historically subjected to phosphorus and nitrogen loading. Recent signs of increasing eutrophication include oxygen deficiency in the bottom waters and large-scale formation of gelatinous macroaggregates. The reason for the formation of these macroaggregates is unclear, but excess production of phytoplankton polysaccharides is suspected. In order to study the effect of different nutrient (nitrogen:phosphorus:silicon) ratios on phytoplankton production, biomass, polysaccharides, and species succession, 4 land-based enclosure experiments were performed with northern Adriatic seawater. During 2 of these experiments the importance of zooplankton grazing as a phytoplankton loss factor was also investigated Primary productivity in the northern Adriatic Sea is thought to be phosphorus limited, and our experiments confirmed that even low daily phosphorus additions increased phytoplankton biomass. However, this only occurred when nitrogen additions were high. Alternatively, when nitrogen was added in low concentrations, with simultaneous high phosphorus additions, phytoplankton biomass declined. Nitrogen deficiency induced the highest production of polysaccharides per unit of cell carbon, while nutrient-sufficient and phosphorus-deficient treatments caused a higher production of polysaccharides in total. In order to decrease the frequency of algal blooms and high polysaccharide production in the northern Adriatic, it appears necessary to reduce the amounts of incoming nutrients. Since phosphorus has a high turnover rate in low P:high N waters of the northern Adriatic, and since our experiments show that a shortage of nitrogen can produce reduced levels of phytoplankton biomass and total polysaccharides, a reduction of the nitrogen discharge would probably be the best countermeasure for eutrophication in the northern Adriatic Sea. C1 Univ Kalmar, Dept Marine Sci, S-39129 Kalmar, Sweden. Univ Massachusetts, Dept Biol, N Dartmouth, MA 02747 USA. NOAA, Natl Marine Fisheries Serv, SE Fisheries Sci Ctr, Beaufort Lab, Beaufort, NC 28516 USA. IFREMER, CNRS, CREMA Lhoumeau, F-17137 Lhoumeau, France. Ist Super Sanita, Lab Igiene Ambientale, I-00161 Rome, Italy. RP Graneli, E (reprint author), Univ Kalmar, Dept Marine Sci, POB 905, S-39129 Kalmar, Sweden. EM edna.graneli@ng.hik.se RI Carlsson, Per/A-4061-2009; Graneli, Edna/F-5936-2015 OI Carlsson, Per/0000-0001-7313-9976; NR 57 TC 33 Z9 35 U1 1 U2 14 PU INTER-RESEARCH PI OLDENDORF LUHE PA NORDBUNTE 23, D-21385 OLDENDORF LUHE, GERMANY SN 0948-3055 J9 AQUAT MICROB ECOL JI Aquat. Microb. Ecol. PD JUL 16 PY 1999 VL 18 IS 1 BP 37 EP 54 DI 10.3354/ame018037 PG 18 WC Ecology; Marine & Freshwater Biology; Microbiology SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Microbiology GA 222LW UT WOS:000081787900004 ER PT J AU Turner, JT Tester, PA Lincoln, JA Carlsson, P Graneli, E AF Turner, JT Tester, PA Lincoln, JA Carlsson, P Graneli, E TI Effects of N : P : Si ratios and zooplankton grazing on phytoplankton communities in the northern Adriatic Sea. III. Zooplankton populations and grazing SO AQUATIC MICROBIAL ECOLOGY LA English DT Article DE zooplankton; grazing; Adriatic Sea; copepod ID MARINE-PHYTOPLANKTON; FEEDING ECOLOGY; SPRING BLOOM; FOOD WEBS; IMPACT; COPEPODS; BIGHT; PLUME AB As part of mesocosm experiments to study effects of nutrients and zooplankton grazing on phytoplankton communities from the northern Adriatic Sea, we monitored metazoan zooplankton fluctuations in enclosures and performed grazing experiments in May and June of 1993. An effort was made to increase zooplankton abundances up to 10 times above normal levels in May, whereas in June, we attempted to initially exclude zooplankters >100 mu m in size. Neither manipulation mattered since, in both cases, a cohort of copepodites rapidly developed from eggs and nauplii added during initial Wing of enclosures. Declines in abundances of nauplii, with concurrent increases in copepodites, during both experiments likely resulted from a combination of nauplii molting into copepodites, and possibly cannibalism of nauplii by copepodites and adults, in May copepodites were almost exclusively Acartia clausi, whereas in June, both A. clausi and particularly Oithona similis copepodites increased in enclosures after 6 to 7 d. Grazing rates by A. clausi adults and copepodites were low in both months (0.01 to 0.35 ml copepod(-1) h(-1) in May, and <0.21 ml copepod(-1) h(-1) in June). Zooplankton community grazing had minimal impact, in that phytoplankton growth continued unabated until nutrients were exhausted. C1 Univ Massachusetts, Dept Biol, N Dartmouth, MA 02747 USA. NOAA, Natl Marine Fisheries Serv, SE Fisheries Sci Ctr, Beaufort Lab, Beaufort, NC 28516 USA. Univ Kalmar, Dept Marine Sci, S-39129 Kalmar, Sweden. RP Turner, JT (reprint author), Univ Massachusetts, Dept Biol, N Dartmouth, MA 02747 USA. RI Graneli, Edna/F-5936-2015 NR 28 TC 7 Z9 7 U1 0 U2 4 PU INTER-RESEARCH PI OLDENDORF LUHE PA NORDBUNTE 23, D-21385 OLDENDORF LUHE, GERMANY SN 0948-3055 J9 AQUAT MICROB ECOL JI Aquat. Microb. Ecol. PD JUL 16 PY 1999 VL 18 IS 1 BP 67 EP 75 DI 10.3354/ame018067 PG 9 WC Ecology; Marine & Freshwater Biology; Microbiology SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Microbiology GA 222LW UT WOS:000081787900006 ER PT J AU Armstrong, JT AF Armstrong, JT TI Determination of chemical valence state by X-ray emission analysis using electron beam instruments: Pitfalls and promises SO ANALYTICAL CHEMISTRY LA English DT Article ID INTENSITY RATIOS; OXIDATION-STATE; THIN-FILMS; MICROPROBE; SUPERCONDUCTORS; SPECTROSCOPY; PARTICLES; CHROMIUM; SPECTRA; OXYGEN AB The use of X-ray emission spectroscopy to determine the valence states of first-row transition elements is evaluated using measurements of X-ray wavelength shifts, line shapes, and relative X-ray line intensities (L beta/L alpha and K beta/ K alpha). X-ray wavelength (or energy) centroids and line shapes are shown to vary not only with oxidation state but also with chemical bonding for the same oxidation state. In many of the cases studied, the ratio of K beta to K alpha is shown to vary depending upon the differential absorption at a similar level to what is cited in the literature as due to the valence state. Similarly, in a number of cases studied, the ratio of L beta to L alpha is shown to vary by differences in self-absorption (and at low electron beam energies, differences in overvoltage) by levels comparable to what is ascribed in the literature as due to valence state. Differences were found among compounds with different oxidation states that exceeded the magnitude predicted by absorption or overvoltage effects; however, no systematic variations were found that were dependent only on the valence state of the element (as opposed to which other elements it was bonded). The results show that oxidation state cannot be simply and unambiguously determined by X-ray emission spectroscopy at the resolution obtainable with conventional wavelength-dispersive detectors on electron microscopes or microprobes. Of the various techniques employed in X-ray emission spectroscopy, the most promising for oxidation-state determination appears to be measurement of the wavelength shift and/or satellite line shape variation, but then only when comparing compounds in which the cation has the same bonding environment. It is critically important to correct for self-absorption effects when attempting to relate variations in L beta/L alpha. to differences in oxidation state or bonding: environment, regardless of the electron beam energy used in analysis. Specifically, L beta/L alpha: measurements cannot be used to determine the oxidation state of Cu in high-temperature superconductors. C1 Natl Inst Stand & Technol, Surface & Microanal Sci Div, Gaithersburg, MD 20899 USA. RP Armstrong, JT (reprint author), Natl Inst Stand & Technol, Surface & Microanal Sci Div, Gaithersburg, MD 20899 USA. NR 73 TC 19 Z9 19 U1 0 U2 5 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0003-2700 J9 ANAL CHEM JI Anal. Chem. PD JUL 15 PY 1999 VL 71 IS 14 BP 2714 EP 2724 DI 10.1021/ac981214q PG 11 WC Chemistry, Analytical SC Chemistry GA 216VM UT WOS:000081465200017 ER PT J AU Chaychian, M Silverman, J Al-Sheikhly, M Poster, DL Neta, P AF Chaychian, M Silverman, J Al-Sheikhly, M Poster, DL Neta, P TI Ionizing radiation induced degradation of tetrachlorobiphenyl in transformer oil SO ENVIRONMENTAL SCIENCE & TECHNOLOGY LA English DT Article ID ELECTRON-TRANSFER; RADICAL-ANIONS; POLYCHLORINATED-BIPHENYLS; WASTE OIL; DESTRUCTION AB Complete degradation of 2,2',6,6'-tetrachlorobiphenyl (PCB-54) in transformer oil is achieved by ionizing radiation without degradation of the oil. gamma-Irradiation of transformer oil containing PCB-54 (0.27 mg/g) with a dose of 200 kGy results in complete (>99%) destruction of the PCB. Analysis of samples irradiated with various doses demonstrated gradual degradation of PCB-54 and successive formation and degradation of trichloro-, dichloro-, and monochlorobiphenyl. The final products are mainly biphenyl and inorganic chloride. The mechanism of reductive degradation is studied by pulse radiolysis. The oil contains many aromatic hydrocarbons; the most abundant being biphenyl, fluorene, and phenanthrene. Solvated electrons formed by irradiation of the oil react either with the PCB to lead to dechlorination or with the aromatic hydrocarbons present in the oil to form radical anions. These species are shown to transfer an electron to chlorinated biphenyls relatively rapidly, leading to dechlorination. The rate constants for several su ch reactions, determined in 2-propanol solutions, are in the range of 10(7)-10(8) L mol(-1) s(-1). These rapid reactions explain why PCB can be dechlorinated in oil despite the presence of aromatic hydrocarbons in the oil and despite the formation of biphenyl as a radiolysis product that reacts rapidly with solvated electrons. C1 Univ Maryland, Dept Mat & Nucl Engn, College Pk, MD 20742 USA. Natl Inst Stand & Technol, Chem Sci & Technol Lab, Gaithersburg, MD 20899 USA. RP Al-Sheikhly, M (reprint author), Univ Maryland, Dept Mat & Nucl Engn, College Pk, MD 20742 USA. NR 24 TC 26 Z9 27 U1 0 U2 5 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 JUL 15 PY 1999 VL 33 IS 14 BP 2461 EP 2464 DI 10.1021/es9900914 PG 4 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA 217CA UT WOS:000081480900022 ER PT J AU Handy, EM Rao, MV Jones, KA Derenge, MA Chi, PH Vispute, RD Venkatesan, T Papanicolaou, NA Mittereder, J AF Handy, EM Rao, MV Jones, KA Derenge, MA Chi, PH Vispute, RD Venkatesan, T Papanicolaou, NA Mittereder, J TI Effectiveness of AlN encapsulant in annealing ion-implanted SiC SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID 6H SILICON-CARBIDE; ALUMINUM; BORON AB Aluminum nitride (AlN) has been used as an encapsulant for annealing nitrogen (N), arsenic (As), antimony (Sb), aluminum (Al), and boron (B) ion-implanted 6H-SiC. Atomic force microscopy has revealed that the AlN encapsulant prevents the formation of long grooves on the SiC surface that are observed if the AlN encapsulant is not used, for annealing cycles up to 1600 degrees C for 15 min. Secondary ion mass spectrometry measurements indicated that the AlN encapsulant is effective in preserving the As and Sb implants, but could not stop the loss of the B implants. Electrical characterization reveals activation of N, As, Sb, and Al implants when annealed with an AlN encapsulant comparable to the best activation achieved without AlN. (C) 1999 American Institute of Physics. [S0021-8979(99)03214-4]. C1 George Mason Univ, Dept Elect & Comp Engn, Fairfax, VA 22030 USA. Army Res Lab, SEDD, Adelphi, MD 20783 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Univ Maryland, Dept Phys, College Pk, MD 20742 USA. USN, Res Lab, Washington, DC 20375 USA. RP Handy, EM (reprint author), George Mason Univ, Dept Elect & Comp Engn, Fairfax, VA 22030 USA. RI Venkatesan, Thirumalai/E-1667-2013 NR 20 TC 38 Z9 41 U1 1 U2 5 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD JUL 15 PY 1999 VL 86 IS 2 BP 746 EP 751 DI 10.1063/1.370798 PG 6 WC Physics, Applied SC Physics GA 211QL UT WOS:000081171800006 ER PT J AU Booth, JC Beall, JA Rudman, DA Vale, LR Ono, RH AF Booth, JC Beall, JA Rudman, DA Vale, LR Ono, RH TI Geometry dependence of nonlinear effects in high temperature superconducting transmission lines at microwave frequencies SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID YBA2CU3O7-DELTA THIN-FILMS; HARMONIC-GENERATION; INTERMODULATION; RESONATOR; FILTERS; MODEL AB We investigate the nature of low-power nonlinear effects in high-temperature superconducting microwave devices by measuring third harmonic generation at 76 K in coplanar waveguide transmission lines of different geometries fabricated from YBa2Cu3O7-delta thin films. The measured power in the third-harmonic signal changes systematically with film thickness, center conductor linewidth, and line length. We analyze these results using a simple model for a transmission line with a nonlinear inductance arising from a current-dependent superconducting penetration depth. This analysis describes quantitatively the observed differences in harmonic generation for transmission lines of different dimensions, and yields a single geometry-independent parameter (the nonlinear scaling current density J(0)) to quantify the observed nonlinear behavior. For the thin film samples studied here J(0)=3.0x10(7) A/cm(2) at 76 K for all geometries investigated. These results provide the means to establish a lower limit for the expected nonlinear response of superconducting components of arbitrary geometry at microwave frequencies. (C) 1999 American Institute of Physics. [S0021-8979(99)05614-5]. C1 Natl Inst Stand & Technol, Boulder, CO 80303 USA. RP Booth, JC (reprint author), Natl Inst Stand & Technol, 325 Broadway, Boulder, CO 80303 USA. NR 21 TC 41 Z9 41 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD JUL 15 PY 1999 VL 86 IS 2 BP 1020 EP 1027 DI 10.1063/1.370841 PG 8 WC Physics, Applied SC Physics GA 211QL UT WOS:000081171800051 ER PT J AU Keller, RR Kalnas, CE Phelps, JM AF Keller, RR Kalnas, CE Phelps, JM TI Local crystallography and stress voiding in Al-Si-Cu versus copper interconnects SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID TEXTURE AB We compare the local crystallographic orientations associated with stress voids in Al-1Si-0.5Cu (wt %) with those in pure copper interconnects. Orientations were sorted by whether grains were immediately adjacent to voids. Grains adjacent to voids in Al-Si-Cu showed a [111] fiber texture that was slightly stronger than those in intact regions. This is in contrast to copper, which showed weaker local [111] texture around voids. We postulate the difference to be due to the relative effectiveness of the diffusion paths available in the lines. For Al-Si-Cu, the presence of defects associated with precipitates may allow more rapid diffusion than grain boundaries. Voiding in copper, which is free from such defects, depends more on grain boundary structure. (C) 1999 American Institute of Physics. [S0021-8979(99)03814-1]. C1 Natl Inst Stand & Technol, Div Mat Reliabil, Boulder, CO 80303 USA. RP Keller, RR (reprint author), Natl Inst Stand & Technol, Div Mat Reliabil, 325 Broadway, Boulder, CO 80303 USA. RI Keller, Robert/I-9014-2012 NR 6 TC 6 Z9 6 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD JUL 15 PY 1999 VL 86 IS 2 BP 1167 EP 1169 DI 10.1063/1.370860 PG 3 WC Physics, Applied SC Physics GA 211QL UT WOS:000081171800073 ER PT J AU Potter, MJ Kirchhoff, PD Carlson, HA McCammon, JA AF Potter, MJ Kirchhoff, PD Carlson, HA McCammon, JA TI Molecular dynamics of cryptophane and its complexes with tetramethylammonium and neopentane using a continuum solvent model SO JOURNAL OF COMPUTATIONAL CHEMISTRY LA English DT Article DE molecular dynamics; implicit solvent; Poisson-Boltzmann; cryptophane; continuum solvent ID POISSON-BOLTZMANN EQUATION; SOLVATION FREE-ENERGIES; BOUNDARY-ELEMENT METHOD; STOCHASTIC DYNAMICS; ALANINE DIPEPTIDE; STRUCTURAL FLUCTUATIONS; SIMULATION; ELECTROSTATICS; PROTEINS; PROGRAM AB Time scales currently obtainable in explicit-solvent molecular dynamics simulations are inadequate for the study of many biologically important processes. This has led to increased interest in the use of continuum solvent models. For such models to be used effectively, it is important that their behavior relative to explicit simulation be clearly understood. Accordingly, 5 ns stochastic dynamics simulations of a derivative of cryptophane-E alone, and complexed with tetramethylammonium and neopentane were carried out. Solvation electrostatics were accounted for;ia solutions to the Poisson equation. Nonelectrostatic aspects of solvation were incorporated using a surface area-dependent energy term. Comparison of the trajectories to those from previously reported 25 ns explicit-solvent simulations shows that use of a continuum solvent model results in enhanced sampling. Use of the continuum solvent model also results in a considerable increase in computational efficiency. The continuum solvent model is found to predict qualitative structural characteristics that are similar to those observed in explicit solvent. However, some differences are significant, and optimization of the continuum parameterization will be required for this method to become a efficient alternative to explicit-solvent simulation. (C) 1999 John Wiley & Sons, Inc. C1 Univ Calif San Diego, Dept Chem & Biochem, La Jolla, CA 92093 USA. Univ Calif San Diego, Dept Pharmacol, La Jolla, CA 92093 USA. RP Potter, MJ (reprint author), Natl Inst Stand & Technol, Ctr Adv Res Biotechnol, 9600 Gudelsky Dr, Rockville, MD 20850 USA. OI Carlson, Heather/0000-0002-7495-1699 NR 36 TC 10 Z9 11 U1 0 U2 2 PU JOHN WILEY & SONS INC PI NEW YORK PA 605 THIRD AVE, NEW YORK, NY 10158-0012 USA SN 0192-8651 J9 J COMPUT CHEM JI J. Comput. Chem. PD JUL 15 PY 1999 VL 20 IS 9 BP 956 EP 970 DI 10.1002/(SICI)1096-987X(19990715)20:9<956::AID-JCC7>3.0.CO;2-R PG 15 WC Chemistry, Multidisciplinary SC Chemistry GA 204TU UT WOS:000080781200007 ER PT J AU Ray-Culp, M Davis, M Stoner, AW AF Ray-Culp, M Davis, M Stoner, AW TI Predation by xanthid crabs on early post-settlement gastropods: the role of prey size, prey density, and habitat complexity SO JOURNAL OF EXPERIMENTAL MARINE BIOLOGY AND ECOLOGY LA English DT Article DE conch; predation; seagrass; Strombus gigas; xanthid crab ID JUVENILE QUEEN CONCH; EARLY POSTSETTLEMENT MORTALITY; BENTHIC MARINE-INVERTEBRATES; STROMBUS-GIGAS LINNAEUS; DEPENDENT MORTALITY; DECAPOD CRUSTACEANS; RECRUITMENT; GROWTH; BEHAVIOR; MICROPREDATORS AB Small predators in marine benthic communities create a hazardous environment for newly settled invertebrates, especially for the smallest individuals. To explore the effects of predation on a newly settled gastropod, queen conch (Strombus gigas Linnaeus), by a xanthid crab (Micropanope sp.), prey size, prey density, and habitat complexity were manipulated in five laboratory experiments. All crabs > 3.1 mm CW killed all conch < 2 mm SL when individual crabs (< 14 mm carapace width (CW)) were offered individual conch that were 2-35 days old after metamorphosis (1.2-8.8 mm shell length (SL)). Only 10% of the crabs > 5.0 mm CW, however, killed conch that were > 5.0 mm SL, suggesting that conch may reach a size refuge from xanthid crabs at 5 mm SL. Furthermore, when given a choice, crabs (4.8 mm CW) preferred smaller conch (2.0 mm SL) to larger (3.7 mm SL), suggesting that 1 week of additional growth in shell length is advantageous to survivorship. Proportional mortality decreased as conch density increased when crabs were offered conch at seven different densities (two to 96 individuals). Crabs proved to be effective predators regardless of the amount of seagrass structure provided in a microcosm experiment, and could consume two conch in 10 s. The high densities of xanthid crabs that occur in the wild, their effectiveness as predators, and their large appetites point to the important role that small predators may potentially play in structuring the population dynamics of their small prey immediately after settlement. (C) 1999 Elsevier Science BN. All rights reserved. C1 Caribbean Marine Res Ctr, Vero Beach, FL 32963 USA. RP Stoner, AW (reprint author), NW Fisheries Sci Ctr, Natl Marine Fisheries Serv, 74 Magruder Rd, Highlands, NJ 07732 USA. EM al.stoner@noaa.gov NR 51 TC 32 Z9 33 U1 3 U2 14 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-0981 J9 J EXP MAR BIOL ECOL JI J. Exp. Mar. Biol. Ecol. PD JUL 15 PY 1999 VL 240 IS 2 BP 303 EP 321 DI 10.1016/S0022-0981(99)00065-9 PG 19 WC Ecology; Marine & Freshwater Biology SC Environmental Sciences & Ecology; Marine & Freshwater Biology GA 218KY UT WOS:000081552800008 ER PT J AU Maes, C Benkiran, M De Mey, P AF Maes, C Benkiran, M De Mey, P TI Sea level comparison between TOPEX/POSEIDON altimetric data and a global ocean general circulation model from an assimilation perspective SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID TROPICAL PACIFIC-OCEAN; LONG EQUATORIAL WAVES; VARIABILITY; OGCM; SIMULATION; TOPOGRAPHY AB The TOPEX/POSEIDON altimetric sea level observations during 1993 are used to validate a simulation made by the Laboratoire d'Oceanographie Dynamique et de Climatologie ocean general circulation model (OGCM) at global scales. The forcing fields are provided by the European Centre for Medium-Range Weather Forecasts reanalysis project. The OGCM is a coarse horizontal resolution model (2 degrees longitude by 1.5 degrees latitude with 31 levels in the vertical), mainly used for climate studies. Horizontal mixing is done along isopycnal surfaces, whereas the parameterization of vertical mixing is based on a local estimate of the turbulent kinetic energy. The comparison is quantitative in the sense that TOPEX/POSEIDON observations are interpolated onto the model grid by an objective interpolation in view of the assimilation case. The model simulation is compared to the observations at large spatial scales of 500 km or more. The basic features of the variability are simulated well by the model, in particular with respect to the annual cycle. Major discrepancies are found in the vicinity of western boundary currents and in the Southern Ocean, due in part to the inadequate horizontal resolution. In anticipation of a future assimilation of the observed sea level a decomposition of the model sea level into baroclinic/barotropic components diagnosed with some dynamical variables of the model is then examined. It is shown that the baroclinic component explains the large seasonal variations confined in the upper layers, whereas the barotropic component is associated with intraseasonal variability. The results of the present study confirm that the model sea level is consistent with the observed large-scale variability, providing a basis for future assimilation of the data into the OGCM to improve the representation of the ocean state. C1 CNRS, OMP, LEGOS, Lab Etud Geophys & Oceanog, F-31401 Toulouse, France. RP Maes, C (reprint author), NCEP, EMC, CMB, Room 807,5200 Auth Rd, Camp Springs, MD 20746 USA. RI maes, christophe/L-4049-2015 OI maes, christophe/0000-0001-6532-7141 NR 29 TC 12 Z9 15 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 JUL 15 PY 1999 VL 104 IS C7 BP 15575 EP 15585 DI 10.1029/1999JC900044 PG 11 WC Oceanography SC Oceanography GA 217RD UT WOS:000081512000006 ER PT J AU Jurdik, E Rasing, T van Kempen, H Bradley, CC McClelland, JJ AF Jurdik, E Rasing, T van Kempen, H Bradley, CC McClelland, JJ TI Surface growth in laser-focused atomic deposition SO PHYSICAL REVIEW B LA English DT Article ID STANDING-WAVE; LITHOGRAPHY AB We present calculations of surface growth in laser-focused nanostructure fabrication. We show that theoretical predictions of the structure profile's shape depend sensitively on the model used to describe the growth, and also on the parameters chosen within the model. This sensitivity illustrates that growth effects can play a major role in laser-focused atomic deposition, and also suggests that this process could be utilized for studies of surface growth mechanisms. C1 Catholic Univ Nijmegen, Mat Res Inst, NL-6525 ED Nijmegen, Netherlands. Natl Inst Stand & Technol, Electron Phys Grp, Gaithersburg, MD 20899 USA. RP Jurdik, E (reprint author), Catholic Univ Nijmegen, Mat Res Inst, Toernooiveld 1, NL-6525 ED Nijmegen, Netherlands. RI Rasing, Theo/D-5207-2012; McClelland, Jabez/A-2358-2015 OI McClelland, Jabez/0000-0001-5672-5965 NR 16 TC 15 Z9 15 U1 0 U2 5 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 JUL 15 PY 1999 VL 60 IS 3 BP 1543 EP 1546 DI 10.1103/PhysRevB.60.1543 PG 4 WC Physics, Condensed Matter SC Physics GA 218KJ UT WOS:000081551500031 ER PT J AU Lin, EK Kolb, R Satija, SK Wu, WL AF Lin, EK Kolb, R Satija, SK Wu, WL TI Enhanced polymer segment exchange kinetics due to an applied shear field SO MACROMOLECULES LA English DT Article ID SLIP TRANSITION; POLYSTYRENE MELTS; SOLID INTERFACE; WALL SLIP; DESORPTION; FLOW; INTERDIFFUSION; ADSORPTION; DYNAMICS; DENSITY C1 NIST, Div Polymers, Gaithersburg, MD 20899 USA. NIST, Ctr Neutron Res, Gaithersburg, MD 20899 USA. RP Lin, EK (reprint author), NIST, Div Polymers, Gaithersburg, MD 20899 USA. NR 23 TC 2 Z9 3 U1 1 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0024-9297 J9 MACROMOLECULES JI Macromolecules PD JUL 13 PY 1999 VL 32 IS 14 BP 4741 EP 4744 DI 10.1021/ma9900737 PG 4 WC Polymer Science SC Polymer Science GA 217JG UT WOS:000081495800038 ER PT J AU Perez-Murano, F Birkelund, K Morimoto, K Dagata, JA AF Perez-Murano, F Birkelund, K Morimoto, K Dagata, JA TI Voltage modulation scanned probe oxidation SO APPLIED PHYSICS LETTERS LA English DT Article ID ATOMIC-FORCE MICROSCOPE; SILICON; NANOFABRICATION; LITHOGRAPHY AB Scanned probe microscope (SPM) oxidation with voltage modulation leads to a significant enhancement of the oxide growth rate, improvement of the aspect ratio of oxide features, and control of the structural and electrical properties of the SPM oxide. Variation of the voltage-pulse parameters confirms that the oxide dimensions can be controlled sensitively over a wide range of pulse parameters and that voltage modulation overcomes the self-limiting character of SPM oxidation by reducing the buildup of space charge within the oxide during growth. The enhancement can be used to increase the writing speed or lower the voltage, both beneficial for practical nanoelectronics fabrication. (C) 1999 American Institute of Physics. [S0003-6951(99)02928-9]. C1 Univ Autonoma Barcelona, Dept Elect Engn, E-08193 Bellaterra, Spain. Matsushita Elect Ind Co Ltd, Osaka 5708501, Japan. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Perez-Murano, F (reprint author), Univ Autonoma Barcelona, Dept Elect Engn, E-08193 Bellaterra, Spain. RI Perez-Murano, Francesc/A-6384-2013 OI Perez-Murano, Francesc/0000-0002-4647-8558 NR 17 TC 64 Z9 65 U1 1 U2 4 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD JUL 12 PY 1999 VL 75 IS 2 BP 199 EP 201 PG 3 WC Physics, Applied SC Physics GA 213GW UT WOS:000081265200017 ER PT J AU Ovchinnikov, YB Muller, JH Doery, MR Vredenbregt, EJD Helmerson, K Rolston, SL Phillips, WD AF Ovchinnikov, YB Muller, JH Doery, MR Vredenbregt, EJD Helmerson, K Rolston, SL Phillips, WD TI Diffraction of a released Bose-Einstein condensate by a pulsed standing light wave SO PHYSICAL REVIEW LETTERS LA English DT Article ID BEAM SPLITTER; ATOMS; DEFLECTION; RADIATION AB We study the diffraction of a released sodium Bose-Einstein condensate by a pulsed standing light wave. The width of the momentum distribution of the diffracted atoms exhibits strong oscillations as a function of the pulse duration, corresponding to periodic focusing and collimation of the condensate inside the standing light wave. Applications of this thick grating regime of diffraction to atom interferometry are discussed. C1 Natl Inst Stand & Technol, Atom Phys Div, PHYS A167, Gaithersburg, MD 20899 USA. Tech Univ Eindhoven, Dept Phys, NL-5600 Eindhoven, Netherlands. RP Muller, JH (reprint author), Natl Inst Stand & Technol, Atom Phys Div, PHYS A167, Gaithersburg, MD 20899 USA. RI Helmerson, Kristian/E-3683-2013; rolston, steven/L-5175-2013; Muller, Jorg Helge/M-5187-2014 OI rolston, steven/0000-0003-1671-4190; Muller, Jorg Helge/0000-0001-6984-0487 NR 24 TC 136 Z9 138 U1 3 U2 9 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 12 PY 1999 VL 83 IS 2 BP 284 EP 287 DI 10.1103/PhysRevLett.83.284 PG 4 WC Physics, Multidisciplinary SC Physics GA 215AC UT WOS:000081358900011 ER PT J AU Ogi, H Takashima, K Ledbetter, H Dunn, ML Shimoike, G Hirao, M Bowen, P AF Ogi, H Takashima, K Ledbetter, H Dunn, ML Shimoike, G Hirao, M Bowen, P TI Elastic constants and internal friction of an SiC-fiber-reinforced Ti-alloy-matrix crossply composite: Measurement and theory SO ACTA MATERIALIA LA English DT Article DE acoustic methods; composites; elastic mechanical properties; electromagnetic acoustic resonance; internal friction ID RESONANT ULTRASOUND SPECTROSCOPY; ELECTROMAGNETIC ACOUSTIC-RESONANCE; SOLIDS; TRANSDUCERS; ATTENUATION; ALUMINUM; STRESS; MODULI; FILM AB The complete elastic-constant tenser C-ij and the corresponding internal friction Q(ij)(-1) for a cross-ply composite are measured. It consists of silicon-carbide fibers in a Ti-6Al-4V matrix; it contained 35 vol.% fibers. With tetragonal symmetry, this composite possesses six independent C-ij and Q(ij)(-1). Principally, two measurement methods were used: noncontacting and point-contact resonance-ultrasound spectroscopy. Specimens were rectangular parallelepipeds measuring a few to several millimeters. By changing the magnetic-field direction, which is needed for the Lorentz-force coupling, a particular macroscopic-vibration-mode group among the eight groups for free vibration of a rectangular parallelepiped could be independently excited and detected. This provides a big advantage in identifying the vibration modes of the observed resonance peaks, whose frequencies yield the C-ij by solving an inverse problem. Contactless coupling allowed the measurement of intrinsic internal friction, avoiding the energy loss associated with contact coupling. The internal-friction tenser was determined by a free-decay method. Theoretical calculations were made using an extended Mori-Tanaka mean-field theory and good theory-measurement agreement was found. (C) 1999 Acta Metallurgica Inc. Published by Elsevier Science Ltd. All rights reserved. C1 Osaka Univ, Grad Sch Engn Sci, Toyonaka, Osaka 5608531, Japan. Natl Inst Stand & Technol, Mat Sci & Engn Lab, Boulder, CO 80303 USA. Tokyo Inst Technol, Precis & Intelligence Lab, Midori Ku, Yokohama, Kanagawa 2268503, Japan. Univ Colorado, Dept Mech Engn, Boulder, CO 80309 USA. Univ Birmingham, Sch Met & Mat, IRC Mat High Performance Applicat, Birmingham B15 2TT, W Midlands, England. RP Ogi, H (reprint author), Osaka Univ, Grad Sch Engn Sci, Machikaneyama 1-3, Toyonaka, Osaka 5608531, Japan. OI DUNN, MARTIN/0000-0002-4531-9176 NR 33 TC 25 Z9 25 U1 1 U2 9 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 9 PY 1999 VL 47 IS 9 BP 2787 EP 2796 DI 10.1016/S1359-6454(99)00124-X PG 10 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 221HV UT WOS:000081722400019 ER PT J AU Srinivasan, SG Cahn, JW Jonsson, H Kalonji, G AF Srinivasan, SG Cahn, JW Jonsson, H Kalonji, G TI Excess energy of grain-boundary trijunctions: An atomistic simulation study SO ACTA MATERIALIA LA English DT Article ID MOLECULAR-DYNAMICS; LINE TENSION AB Atomic-scale computer simulation was used to study grain-boundary trijunctions, which are defined as the intersection of three grain boundaries. The simulation system consisted of a three-dimensional periodic array of columnar f.c.c. grains having three different orientations with a common [001] direction, and in which all grains are rotated 30 degrees from their neighbors. The inter-atomic interactions were described by the Lennard-Jones potential. Each simulation cell contained six trijunctions plus the nine associated symmetric tilt grain boundaries. The energy of systems of differing sizes was monitored during annealing and after quenching to obtain quantitative estimates of the excess energy of the grain boundaries and trijunctions. For this system, the total excess energy contributed by the trijunctions was found to be negative. This result is consistent with recent calorimetry experiments on high-purity nanocrystalline cobalt conducted elsewhere. (C) 1999 Published by Elsevier Science Ltd. On behalf of Acta Metallurgica Inc. All rights reserved. C1 Univ Washington, Dept Mat Sci & Engn, Seattle, WA 98195 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Univ Washington, Dept Chem, Seattle, WA 98195 USA. RP Srinivasan, SG (reprint author), Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RI Jonsson, Hannes/G-2267-2013 OI Jonsson, Hannes/0000-0001-8285-5421 NR 20 TC 54 Z9 54 U1 2 U2 9 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 9 PY 1999 VL 47 IS 9 BP 2821 EP 2829 DI 10.1016/S1359-6454(99)00120-2 PG 9 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 221HV UT WOS:000081722400022 ER PT J AU Ruzgas, T Gaigalas, A Gorton, L AF Ruzgas, T Gaigalas, A Gorton, L TI Diffusionless electron transfer of microperoxidase-11 on gold electrodes SO JOURNAL OF ELECTROANALYTICAL CHEMISTRY LA English DT Article DE hemepeptide; microperoxidase-11; electrocatalysis; peptide-modified electrodes; interfacial electron-transfer ID SELF-ASSEMBLED MONOLAYERS; CYTOCHROME-C; ELECTROCATALYTIC REDUCTION; REFLECTANCE SPECTROSCOPY; DIRECT ELECTROCHEMISTRY; SILVER ELECTRODE; SURFACES; CHAIN; ELECTROREFLECTANCE; HEMOPROTEINS AB Microperoxidase-11, MP-11, is made by proteolytic digestion of cytochrome c, cyt. c. It consists of a polypeptide of 11 amino residues attached covalently to the heme. Given that MP-11 has a more exposed heme than the complete protein, it would seem that electron transfer, ET, between immobilized MP-11 and electrodes would be at least as fast as for intact cyt. c. However, while the maximal heterogeneous ET rate for immobilized cyt. c is around 1000 s(-1), that reported previously for immobilized MP-11 does not exceed 20 s(-1). This work attempts to understand this difference in measured ET rates. The MP-11 was immobilized on gold electrodes using several protocols: (electrode A) the immobilization was done following a previously published carbodiimide based recipe yielding ET rates of the order of 20 s(-1); (B) MP-11 was bound to gold electrodes by Lomant's reagent and gave an ET rate close to 4000 s(-1); (C) physisorbed MP-11 on gold electrodes with a self assembled monolayer, SAM, of alkane thiols gave an ET rate approaching 2000 s(-1) for the shortest length alkane thiol. Inspection of the immobilization chemistries suggests that the procedure employed in producing electrodes B and C are likely to lead to a monolayer or less of immobilized MP-11 while the procedure employed for electrode A may lead to a film comprised of a multilayer of MP-11. The presence of such a film on electrode A complicates the ET process since the MP-11 in the layer adjacent to the electrode could have fast ET rates while the MP-11 in the outer layers may have significantly slower ET rates. The net result would be an apparent ET rate constant which is much smaller than the value for the first layer. The measurements and calculations are presented in support of such an interpretation. (C) 1999 Elsevier Science S.A. All rights reserved. C1 Univ Lund, Dept Analyt Chem, S-22100 Lund, Sweden. NIST, Div Biotechnol, Gaithersburg, MD 20899 USA. RP Ruzgas, T (reprint author), Univ Lund, Dept Analyt Chem, POB 124, S-22100 Lund, Sweden. RI Ruzgas, Tautgirdas/C-4646-2008 NR 45 TC 48 Z9 49 U1 0 U2 10 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0022-0728 J9 J ELECTROANAL CHEM JI J. Electroanal. Chem. PD JUL 9 PY 1999 VL 469 IS 2 BP 123 EP 131 DI 10.1016/S0022-0728(99)00194-1 PG 9 WC Chemistry, Analytical; Electrochemistry SC Chemistry; Electrochemistry GA 219GG UT WOS:000081599100004 ER PT J AU Fahey, DW Ravishankara, AR AF Fahey, DW Ravishankara, AR TI Atmospheric science Summer in the stratosphere SO SCIENCE LA English DT Editorial Material ID OZONE C1 NOAA, Aeron Lab, Boulder, CO 80303 USA. RP Fahey, DW (reprint author), NOAA, Aeron Lab, 325 Broadway, Boulder, CO 80303 USA. EM ravi@al.noaa.gov RI Ravishankara, Akkihebbal/A-2914-2011; Fahey, David/G-4499-2013 OI Fahey, David/0000-0003-1720-0634 NR 15 TC 30 Z9 30 U1 0 U2 3 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 9 PY 1999 VL 285 IS 5425 BP 208 EP 210 DI 10.1126/science.285.5425.208 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 214UM UT WOS:000081346000027 ER PT J AU Delaney, N Faeder, J Parson, R AF Delaney, N Faeder, J Parson, R TI Photodissociation and recombination of solvated I-2(-): What causes the transient absorption peak? SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID NONADIABATIC MOLECULAR-DYNAMICS; I2-(CO2)N CLUSTER IONS; VIBRATIONAL-RELAXATION; CHARGE FLOW; SOLVENT DYNAMICS; I2; I-2(-)CENTER-DOT-AR-N; PHOTOFRAGMENTATION; SPECTROSCOPY; SIMULATIONS AB Using nonadiabatic molecular dynamics simulations, we present evidence that the 2 ps peak in the pump-probe spectrum of I-2(-) dissociated inside CO2 clusters is due to transitions from the ground state to the spin-orbit excited states, rather than to excited-state absorption as previously assigned. (C) 1999 American Institute of Physics. [S0021-9606(99)02426-5]. C1 Univ Colorado, Natl Inst Stand & Technol, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. Univ Colorado, Dept Chem & Biochem, Boulder, CO 80309 USA. RP Parson, R (reprint author), Univ Colorado, Natl Inst Stand & Technol, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. NR 30 TC 17 Z9 17 U1 1 U2 4 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD JUL 8 PY 1999 VL 111 IS 2 BP 452 EP 455 DI 10.1063/1.479324 PG 4 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 209UM UT WOS:000081067300003 ER PT J AU Delaney, N Faeder, J Parson, R AF Delaney, N Faeder, J Parson, R TI Simulation of UV photodissociation of I-2(-)(CO2)(n): Spin-orbit quenching via solvent mediated electron transfer SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID FEMTOSECOND PHOTOELECTRON-SPECTROSCOPY; NONADIABATIC MOLECULAR-DYNAMICS; I2-(CO2)N CLUSTER IONS; GEMINATE RECOMBINATION DYNAMICS; STIMULATED RAMAN-SCATTERING; HOMONUCLEAR DIATOMIC IONS; POTENTIAL-ENERGY CURVES; VB RESONANCE THEORY; VIBRATIONAL-RELAXATION; ULTRAFAST PHOTODISSOCIATION AB We simulate the 395 nm photodissociation of I-2(-) embedded in clusters of 6 to 22 CO2 molecules. In the isolated molecule, photodissociation at this wavelength leads exclusively to spin-orbit excited iodine (I*) plus I-. In the larger clusters we observe efficient electronic relaxation, leading both to dissociated products containing ground-state iodine and to recombined products containing I-2(-). The time scale and cluster size dependence of the spin-orbit quenching process agree well with experimental determinations of Sanov et al. (companion paper). The simulation trajectories show that spin-orbit quenching occurs by resonant charge transfer from solvated I- to a nascent I* atom. A model derived from the theory of electron transfer reactions in solution illustrates that this resonance arises when the I spin-orbit energy is compensated by the difference between the solvation energies of the ion and the neutral. (C) 1999 American Institute of Physics. [S0021-9606(99)01626-8]. C1 Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. Univ Colorado, Dept Chem & Biochem, Boulder, CO 80309 USA. Natl Inst Stand & Technol, Boulder, CO 80309 USA. RP Parson, R (reprint author), Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. NR 67 TC 19 Z9 19 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD JUL 8 PY 1999 VL 111 IS 2 BP 651 EP 663 DI 10.1063/1.479345 PG 13 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 209UM UT WOS:000081067300026 ER PT J AU Sanov, A Sanford, T Nandi, S Lineberger, WC AF Sanov, A Sanford, T Nandi, S Lineberger, WC TI Spin-orbit relaxation and recombination dynamics in I-2(-)(CO2)(n) and I-2(-)(OCS)(n) cluster ions: A new type of photofragment caging reaction SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID FEMTOSECOND PHOTOELECTRON-SPECTROSCOPY; NONADIABATIC MOLECULAR-DYNAMICS; SOLVATION ULTRAFAST DYNAMICS; STIMULATED RAMAN-SCATTERING; VB RESONANCE THEORY; VIBRATIONAL-RELAXATION; GEMINATE RECOMBINATION; CHARGE FLOW; PHOTODISSOCIATION PATHWAYS; INCOHERENT CONTROL AB We report a new type of photofragment caging reaction that is only possible because of the strong solvent-induced perturbation of the inherent electronic structure of the chromophore. The photoexcitation of I-2(-) at 395 nm promotes it to a dissociative state correlating with I- + I*(P-2(1/2)), the only near-ultraviolet dissociation channel for unsolvated I-2(-). In I-2(-)(CO2)(n) and I-2(-)(OCS)(n) clusters, interaction with the solvent is observed to result in extremely fast spin-orbit relaxation. In general, we detect three reaction pathways: (1) direct dissociation of the chromophore to I- + I*(P-2(1/2)); (2) the I-2(-) --> I- + I* dissociation, followed by spin-orbit quenching leading to I- + I(P-2(3/2)) products; and (3) the I-2(-) --> I- + I* dissociation, followed by spin-orbit quenching and I- + I(P-2(3/2)) --> I-2(-) recombination and vibrational relaxation. We present experimental evidence of the spin-orbit relaxation and caging and discuss possible mechanisms. The results include: the measured translational energy release in 395 nm photodissociation of unsolvated I-2(-), indicating that solvation-free dissociation proceeds exclusively via the I- + I* channel; ionic product distributions in the photodissociation of size-selected I-2(-)(CO2)(n) and I-2(-)(OCS)(n) clusters at the same wavelength, indicating the above three reaction channels; and ultrafast pump-probe measurements of absorption recovery, indicating picosecond time scales of the caging reaction. We rule out the mechanisms of spin-orbit quenching relying on I*-solvent interactions without explicitly considering the perturbed electronic structure of I-2(-). Instead, as described by Delaney et al. (companion paper), the spin-orbit relaxation occurs by electron transfer from I- to I*(P-2(1/2)), giving I(P-2(3/2)) + I-. The 0.93 eV gap between the initial and final states in this transition is bridged by differential solvation due to solvent asymmetry. Favorable comparison of our experimental results and the theoretical simulations of Delaney et al. yield confidence in the mechanism and provide understanding of the role of cluster structure in spin-orbit relaxation and recombination dynamics. (C) 1999 American Institute of Physics. [S0021-9606(99)01726-2]. C1 Natl Inst Stand & Technol, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. Univ Colorado, Dept Chem & Biochem, Boulder, CO 80309 USA. RP Sanov, A (reprint author), Natl Inst Stand & Technol, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. NR 81 TC 47 Z9 47 U1 0 U2 6 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD JUL 8 PY 1999 VL 111 IS 2 BP 664 EP 675 DI 10.1063/1.479346 PG 12 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 209UM UT WOS:000081067300027 ER PT J AU Das, TN Huie, RE Neta, P Padmaja, S AF Das, TN Huie, RE Neta, P Padmaja, S TI Reduction potential of the sulfhydryl radical: Pulse radiolysis and laser flash photolysis studies of the formation and reactions of center dot SH and HSSH center dot(-) in aqueous solutions SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID HYDROGEN-SULFIDE; SYNERGISTIC OXIDATION; GIF CONDITIONS; KINETICS; SEAWATER; H2S; AUTOXIDATION; MECHANISM; DIOXYGEN; ELECTRON AB Formation and reactions of the . SH/. S- and HSSH .(-)/HSS .(2-) radicals in aqueous solutions have been studied by excimer laser flash photolysis and by pulse radiolysis. Acidic H2S solutions can be photolyzed with 193 nm laser pulses and produce a transient species with lambda(max) at 240 nm, ascribed to the . SH/. S- radical. Solutions of SH- can be photolyzed also with 248 nm laser pulses to produce the . SH/. S- radical. The same radical is formed by oxidation of SH- ions with SO4.(-) and CO3.(-) radicals. At pH > 5, . SH/. S- reacts with SH- (k(f) = 4 x 10(9) L mol(-1) s(-1), k(r) = 5 x 10(5) s(-1)) to form HSSH .(-)/HSS .(2-), with lambda(max) at 380 nm. Both . SH/. S- and HSSH .(-)/HSS .(2-) react rapidly with O-2; the former produces SO2.(-) (k = 5 x 10(9) L mol(-1) s(-1)), and the latter produces O-2.(-) (k = 4 x 10(8) L mol(-1) s(-1)). Both radicals react with olefinic compounds. The monomeric radical oxidizes Fe(CN)(6)(4-), SO32-, ClO2-, and chlorpromazine. The dimeric radical is a weaker oxidant toward ferrocyanide but reduces N-methylpyridinium compounds. The reduction potential for the dimeric radical at pH 7 was determined from one-electron transfer equilibria with Mo(CN)(8)(3-) and with the 4-methoxyaniline radical cation and found to be 0.69 V vs NHE. From the equilibrium constant K = [HSS .(2-)]/[SH-][. S-] = 8 x 10(3) L mol(-1), the reduction potential for (. S-,H+/SH-) is calculated to be 0.92 V. C1 Natl Inst Stand & Technol, Phys & Chem Properties Div, Gaithersburg, MD 20899 USA. RP Huie, RE (reprint author), Natl Inst Stand & Technol, Phys & Chem Properties Div, Gaithersburg, MD 20899 USA. RI Huie, Robert/A-5645-2010 NR 36 TC 44 Z9 45 U1 0 U2 12 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 8 PY 1999 VL 103 IS 27 BP 5221 EP 5226 DI 10.1021/jp9907544 PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 216ZE UT WOS:000081473700001 ER PT J AU Muzny, CD Butler, BD Hanley, HJM Agamalian, M AF Muzny, CD Butler, BD Hanley, HJM Agamalian, M TI An ultra-small-angle neutron scattering study of the restructuring of sheared colloidal silica gels SO JOURNAL OF PHYSICS-CONDENSED MATTER LA English DT Letter AB Neutron scattering curves for a sheared colloidal silica gel were measured using a Bonse-Hart ultra-small-angle neutron scattering instrument. When they are combined with data taken from a conventional small-angle neutron scattering instrument, the accessible scattering vector range extends over approximately four orders of magnitude: 3 x 10(-4) < q (nm(-1)) < 3. A peak in the scattering datais observed at q = 2.7 x 10(-3) nm(-1) corresponding to a correlation length of 2.3 mu m. The scattering curves show an approximate power-law behaviour with an exponent of -2.9 over the range 4 x 10(-3) < q (nm(-1)) < 4 x 10(-2). These results are compared with our previously reported observation that an unsheared sample yields a correlation length of only similar to 20 nm with no observable power-law regime. The present data confirm that shear stresses induce a structural densification in gelling colloidal silica systems. C1 Natl Inst Stand & Technol, Boulder, CO 80303 USA. Oak Ridge Natl Lab, Spallat Neutron Source, Oak Ridge, TN 37831 USA. RP Muzny, CD (reprint author), Natl Inst Stand & Technol, 325 Broadway, Boulder, CO 80303 USA. OI Agamalian, Michael/0000-0002-9112-2534 NR 8 TC 9 Z9 9 U1 0 U2 3 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 5 PY 1999 VL 11 IS 26 BP L295 EP L298 DI 10.1088/0953-8984/11/26/101 PG 4 WC Physics, Condensed Matter SC Physics GA 217NJ UT WOS:000081505600001 ER PT J AU Gardner, JS Gaulin, BD Lee, SH Broholm, C Raju, NP Greedan, JE AF Gardner, JS Gaulin, BD Lee, SH Broholm, C Raju, NP Greedan, JE TI Glassy statics and dynamics in the chemically ordered pyrochlore anti-ferromagnet Y2Mo2O7 SO PHYSICAL REVIEW LETTERS LA English DT Article ID FRUSTRATED PYROCHLORE; SPIN-GLASS; KAGOME ANTIFERROMAGNET; RANGE ORDER; LIQUID; TB2MO2O7 AB Static and dynamic magnetic correlations in the geometrically frustrated pyrochlore antiferromagnet Y2Mo2O7 have been studied using neutron scattering. The material is chemically ordered but displays a spin-freezing transition at T-g similar to 22.5 K. We show that dynamic short range order develops below room temperature. Upon cooling the two-spin correlation length never exceeds 5 Angstrom, yet the spin fluctuation rate vanishes in proportion to T - T-g. For T < T-g law energy spin fluctuations are replaced by static antiferromagnetic short range order with a frozen staggered magnetization \< S >\/S approximate to 0.67(2). Locally the frozen spin structure corresponds to four sublattice ordering with zero magnetization. C1 McMaster Univ, Dept Phys & Astron, Hamilton, ON L8S 4M1, Canada. NIST, Gaithersburg, MD 20899 USA. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. McMaster Univ, Brockhouse Inst Mat Res, Hamilton, ON L8S 4M1, Canada. RP Gardner, JS (reprint author), McMaster Univ, Dept Phys & Astron, Hamilton, ON L8S 4M1, Canada. RI Broholm, Collin/E-8228-2011; Piper, Walter/B-7908-2009; Gardner, Jason/A-1532-2013 OI Broholm, Collin/0000-0002-1569-9892; NR 29 TC 140 Z9 140 U1 2 U2 23 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 5 PY 1999 VL 83 IS 1 BP 211 EP 214 DI 10.1103/PhysRevLett.83.211 PG 4 WC Physics, Multidisciplinary SC Physics GA 212VH UT WOS:000081238000053 ER PT J AU Karl, TR AF Karl, TR TI Better tools for better decisions SO SCIENTIST LA English DT Editorial Material C1 Natl Climat Data Ctr, Asheville, NC 28801 USA. RP Karl, TR (reprint author), Natl Climat Data Ctr, Asheville, NC 28801 USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU SCIENTIST INC PI PHILADELPHIA PA 3600 MARKET ST SUITE 450, PHILADELPHIA, PA 19104 USA SN 0890-3670 J9 SCIENTIST JI Scientist PD JUL 5 PY 1999 VL 13 IS 14 BP 12 EP 12 PG 1 WC Information Science & Library Science; Multidisciplinary Sciences SC Information Science & Library Science; Science & Technology - Other Topics GA 213KC UT WOS:000081270700008 ER PT J AU Wenthold, PG Lineberger, WC AF Wenthold, PG Lineberger, WC TI Negative ion photoelectron spectroscopy studies of organic reactive intermediates SO ACCOUNTS OF CHEMICAL RESEARCH LA English DT Review ID TRANSITION-STATE SPECTROSCOPY; GROUND-STATE; RING-CLOSURE; EXCITATION-ENERGIES; ELECTRON-AFFINITY; ACTIVATION-ENERGY; RADICAL-ANION; TRIMETHYLENEMETHANE; SINGLET; CYCLOOCTATETRAENE C1 Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. Univ Colorado, Dept Chem & Biochem, Boulder, CO 80309 USA. Natl Inst Stand & Technol, Boulder, CO 80309 USA. RP Lineberger, WC (reprint author), Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. NR 72 TC 60 Z9 60 U1 7 U2 20 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0001-4842 J9 ACCOUNTS CHEM RES JI Accounts Chem. Res. PD JUL PY 1999 VL 32 IS 7 BP 597 EP 604 DI 10.1021/ar960121x PG 8 WC Chemistry, Multidisciplinary SC Chemistry GA 220RG UT WOS:000081680800007 ER PT J AU Duthinh, D AF Duthinh, D TI Sensitivity of sheer strength of reinforced concrete and prestressed concrete beams to shear friction and concrete softening according to modified compression field theory SO ACI STRUCTURAL JOURNAL LA English DT Article DE aggregate interlock; beams; compression; prestressed concrete; reinforced concrete; shear AB The modified compression field theory (MCFT) is used to study the effect of shear friction and biaxial softening on the computed shear strength of reinforced (RC) or prestressed concrete (PC) beams. A comparison is presented of the various relationships that have been proposed to represent the shear friction behavior of cracked reinforced concrete A decrease in shear friction within the range of experimental data as found, for example, in high-strength concrete, can lower the shear strength of beams with minimum shear reinforcement by 15 to 25 percent, according to the MCFT. In addition, a comparison is presented of different relationships used to represent the biaxial compression-tension strength of reinforced concrete for RC and PC beams. Some theories of biaxial softening of concrete do not predict concrete crushing even for very high deformations, but rather show significant shear force gain after stirrup yielding and crack slipping. For the RC beam example, some theories predict shear tension failure while others predict diagonal compression failure However the first peaks of shear load which occur close to stirrup yielding and crack slipping, are within 10 percent of one another for the various theories and within 10 percent of the test value for the PC beam. C1 Natl Inst Stand & Technol, Bldg & Fire Res Lab, Gaithersburg, MD 20899 USA. RP Duthinh, D (reprint author), Natl Inst Stand & Technol, Bldg & Fire Res Lab, Gaithersburg, MD 20899 USA. NR 47 TC 12 Z9 12 U1 1 U2 3 PU AMER CONCRETE INST PI FARMINGTON HILLS PA 38800 INTERNATIONAL WAY, COUNTRY CLUB DRIVE, PO BOX 9094, FARMINGTON HILLS, MI 48333-9094 USA SN 0889-3241 J9 ACI STRUCT J JI ACI Struct. J. PD JUL-AUG PY 1999 VL 96 IS 4 BP 495 EP 508 PG 14 WC Construction & Building Technology; Engineering, Civil; Materials Science, Multidisciplinary SC Construction & Building Technology; Engineering; Materials Science GA 291WL UT WOS:000085762200005 ER PT J AU El-Bahy, A Kunnath, SK Stone, WC Taylor, AW AF El-Bahy, A Kunnath, SK Stone, WC Taylor, AW TI Cumulative seismic damage of circular bridge columns: Benchmark and low-cycle fatigue tests SO ACI STRUCTURAL JOURNAL LA English DT Article DE bridges (structures); cyclic loads; damage; ductility; earthquake-resistant structures; fatigue tests AB An experimental study was undertaken to investigate cumulative damage in reinforced concrete circular bridge piers subjected to a series of earthquake excitations. Twelve identical quarter-scale bridge columns, designed in accordance with current AASHTO specifications, were fabricated and tested to failure. This paper summarizes the results of Phase I testing that consisted of benchmark tests to establish the monotonic force-deformation envelope and the energy capacity under standard cyclic loads, and constant amplitude tests to determine the low-cycle fatigue characteristics of typical flexural bridge columns. A companion paper will present the results of variable amplitude testing that focused on the effects of load path on cumulative damage. Test observations indicate two potential failure modes: low cycle fatigue of the longitudinal reinforcing bars; and confinement failure due to rupture of the confining spirals. The former failure mode is associated with relatively large displacement amplitudes in excess of 4 percent lateral drift, while the latter is associated with a larger number of smaller amplitude cycles. A fatigue life expression is developed that call be used in damage-based seismic design of circular, flexular bridge columns. C1 Univ Cent Florida, Orlando, FL 32816 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. KPFF Consulting Engn, Seattle, WA USA. NR 20 TC 44 Z9 52 U1 0 U2 2 PU AMER CONCRETE INST PI FARMINGTON HILLS PA 38800 INTERNATIONAL WAY, COUNTRY CLUB DRIVE, PO BOX 9094, FARMINGTON HILLS, MI 48333-9094 USA SN 0889-3241 J9 ACI STRUCT J JI ACI Struct. J. PD JUL-AUG PY 1999 VL 96 IS 4 BP 633 EP 641 PG 9 WC Construction & Building Technology; Engineering, Civil; Materials Science, Multidisciplinary SC Construction & Building Technology; Engineering; Materials Science GA 291WL UT WOS:000085762200020 ER PT J AU Majkrzak, CF AF Majkrzak, CF TI Neutron reflectometry studies of thin films and multilayered materials SO ACTA PHYSICA POLONICA A LA English DT Article; Proceedings Paper CT 3rd International School and Symposium on Physics in Materials Science (ISSPMS 98) CY SEP 13-19, 1998 CL JASZOWIEC, POLAND ID SUPERLATTICES; SCATTERING; REFLECTION; INTERFACES; SURFACES; EXCHANGE; PHASE AB Neutron reflectometry is an important technique for studying the composition and structure of thin films and layered media on a nanometer scale. Neutrons are particularly useful as probes of organic and magnetic materials since the information that can be obtained is often unique. Furthermore, the fact that neutrons traverse relatively large distances in single crystalline materials, such as silicon, permit investigations in diverse sample environments. The fundamental theoretical principles and experimental methodology of neutron reflectometry are presented, in addition to several illustrative examples of measurements relevant to polymer science, biology, electrochemistry, and magnetism. C1 Natl Inst Stand & Technol, Ctr Neutron Res, Gaithersburg, MD 20899 USA. RP Majkrzak, CF (reprint author), Natl Inst Stand & Technol, Ctr Neutron Res, Gaithersburg, MD 20899 USA. NR 28 TC 14 Z9 15 U1 0 U2 6 PU POLISH ACAD SCIENCES INST PHYSICS PI WARSAW PA AL LOTNIKOW 32-46, 02-668 WARSAW, POLAND SN 0587-4246 J9 ACTA PHYS POL A JI Acta Phys. Pol. A PD JUL PY 1999 VL 96 IS 1 BP 81 EP 99 PG 19 WC Physics, Multidisciplinary SC Physics GA 224BB UT WOS:000081875100007 ER PT J AU Mulholland, GW Bryner, NP Croarkin, C AF Mulholland, GW Bryner, NP Croarkin, C TI Measurement of the 100 nm NIST SRM 1963 by differential mobility analysis SO AEROSOL SCIENCE AND TECHNOLOGY LA English DT Article ID SLIP CORRECTION MEASUREMENTS; LIGHT-SCATTERING; PARTICLES AB The number mean diameter of 100 nm NIST Standard Reference Material (SRM) 1963 was measured to be 100.7 nm with an expanded uncertainty at the 95% confidence level of 1.0 nm by measurement,vith the differential mobility analyzer (DMA). The low level of uncertainty resulted from the use of the 1.0 mu m SRM 1690 for calibrating the DMA. The largest single component of the Type B (systematic) uncertainty was a 0.29 nm uncertainty in the calibration diameter. Measurements of the 0.3 mu m SRM with the calibrated DMA give results within 0.001 mu m of the certified diameter. Results obtained by other investigators using transmission electron microscopy (TEM), angle dependent light scattering, electro-gravitational aerosol balance, and atomic force microscopy are consistent with this DMA value. The 100 nm NIST SRM 1963 and the Japanese 100 nm Calibration Standard are shown to differ by 10% based on TEM analysis and DMA measurements. This size difference has a significant effect on the calibration of scanning surface inspection systems and optical particle counters. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Mulholland, GW (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NR 16 TC 32 Z9 32 U1 0 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 PY 1999 VL 31 IS 1 BP 39 EP 55 PG 17 WC Engineering, Chemical; Engineering, Mechanical; Environmental Sciences; Meteorology & Atmospheric Sciences SC Engineering; Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA 217PU UT WOS:000081508800004 ER PT J AU Fox, PJ Scholten, RE Walkiewicz, MR Drullinger, RE AF Fox, PJ Scholten, RE Walkiewicz, MR Drullinger, RE TI A reliable, compact, and low-cost Michelson wavemeter for laser wavelength measurement SO AMERICAN JOURNAL OF PHYSICS LA English DT Article ID DIODE-LASER; CW LASERS; ACCURACY; SYSTEM AB We describe the construction and operation of a simple, compact, and cost effective Michelson wavemeter with picometer accuracy. The low cost of the device means that it can form the basis of an undergraduate laboratory experiment, yet it is sufficiently reliable and accurate that it has become an important tool in our research laboratory, where it is regularly used to tune lasers to atomic transitions. The usefulness and accuracy of the wavemeter is demonstrated by tuning two separate extended cavity diode lasers to achieve two-step excitation of the Rb 5(2)D state, observed by detecting 420 nm blue fluorescence from the 5(2)D-->6(2)p-->5(2)S decay path. (C) 1999 American Association of Physics Teachers. C1 Univ Melbourne, Sch Phys, Parkville, Vic 3052, Australia. Natl Inst Stand & Technol, Div Time & Frequency, Boulder, CO 80303 USA. RP Fox, PJ (reprint author), Univ Melbourne, Sch Phys, Parkville, Vic 3052, Australia. RI Scholten, Robert/A-8586-2013 OI Scholten, Robert/0000-0002-2337-8036 NR 27 TC 39 Z9 42 U1 0 U2 4 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0002-9505 J9 AM J PHYS JI Am. J. Phys. PD JUL PY 1999 VL 67 IS 7 BP 624 EP 630 DI 10.1119/1.19335 PG 7 WC Education, Scientific Disciplines; Physics, Multidisciplinary SC Education & Educational Research; Physics GA 211AD UT WOS:000081137000011 ER PT J AU McKeown, DA Bell, MI Etz, ES AF McKeown, DA Bell, MI Etz, ES TI Vibrational analysis of the dioctahedral mica: 2M(1) muscovite SO AMERICAN MINERALOGIST LA English DT Article ID RING; BENITOITE AB Raman spectra and lattice dynamics calculations are presented for the dioctahedral mica, muscovite. Calculated fundamental mode frequencies for the Raman-active and A(g) and B-g species were fit to observed fundamentals assigned to features in the two polarized Raman spectra collected, so that unambiguous vibrational assignments could be made to most peaks in the Raman data. Calculated frequencies for the IR-active A(u) and B-u modes generally fall within the frequency ranges of bands in the IR spectra for muscovite presented earlier. Factor group analysis indicates that motion from all atom types in the muscovite structure can be found in modes for all four vibrational species. Force constant values determined for muscovite are similar to equivalent values calculated for the trioctahedral mica, phlogopite. Raman and IR-active modes calculated at frequencies greater than 800 cm(-1) are dominated by internal sheet T-O stretch and T-O-T bend motions, where T is a tetrahedral site. Modes between 800 and 360 cm(-1) have internal tetrahedral sheet motions mixed with K and octahedral Al displacements. Modes at frequencies less than 360 cm(-1) have lattice and OH motions. Inter-sheet bonding in the muscovite structure is strong enough to affect modes at frequencies as high as 824 cm(-1). C1 Catholic Univ Amer, Vitreous State Lab, Washington, DC 20064 USA. USN, Res Lab, Dynam Solids Branch, Washington, DC 20375 USA. Natl Inst Stand & Technol, Surface & Microanal Sci Div, Gaithersburg, MD 20899 USA. RP McKeown, DA (reprint author), Catholic Univ Amer, Vitreous State Lab, 620 Michigan Ave NE, Washington, DC 20064 USA. NR 12 TC 44 Z9 45 U1 0 U2 15 PU MINERALOGICAL SOC AMER PI WASHINGTON PA 1015 EIGHTEENTH ST, NW SUITE 601, WASHINGTON, DC 20036 USA SN 0003-004X J9 AM MINERAL JI Am. Miner. PD JUL-AUG PY 1999 VL 84 IS 7-8 BP 1041 EP 1048 PG 8 WC Geochemistry & Geophysics; Mineralogy SC Geochemistry & Geophysics; Mineralogy GA 213FB UT WOS:000081261100006 ER PT J AU Wu, CM Lawall, J Deslattes, RD AF Wu, CM Lawall, J Deslattes, RD TI Heterodyne interferometer with subatomic periodic nonlinearity SO APPLIED OPTICS LA English DT Article AB A new, to our knowledge, heterodyne interferometer for differential displacement measurements is presented. It is, in principle, fi-ee of periodic nonlinearity. A pair of spatially separated light beams with different frequencies is produced by two acousto-optic modulators, avoiding the main source of periodic nonlinearity in. traditional heterodyne interferometers that are based on a Zeeman split laser. In addition, laser beams of the same frequency are used in the measurement and the reference arms, giving the interferometer theoretically perfect immunity from common-mode displacement. We experimentally demonstrated a residual level of periodic nonlinearity of less than 20 pm in amplitude. The remaining periodic error is attributed to unbalanced ghost reflections that drift slowly with time. (C) 1999 Optical Society of America. C1 Natl Inst Stand & Technol, Phys Lab, Gaithersburg, MD 20899 USA. RP Wu, CM (reprint author), Natl Inst Stand & Technol, Phys Lab, Bldg 221,Room A141, Gaithersburg, MD 20899 USA. EM john.lawall@nist.gov RI Wu, Chien-ming/K-6361-2012 OI Wu, Chien-ming/0000-0002-4985-386X NR 7 TC 78 Z9 81 U1 2 U2 7 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 1999 VL 38 IS 19 BP 4089 EP 4094 DI 10.1364/AO.38.004089 PG 6 WC Optics SC Optics GA 212GF UT WOS:000081208400014 PM 18323886 ER PT J AU Silverstein, JT Shearer, KD Dickhoff, WW Plisetskaya, EM AF Silverstein, JT Shearer, KD Dickhoff, WW Plisetskaya, EM TI Regulation of nutrient intake and energy balance in salmon SO AQUACULTURE LA English DT Article; Proceedings Paper CT 3rd International Symposium on Research for Aquaculture - Fundamental and Applied Aspects CY AUG 24-27, 1997 CL BARCELONA, SPAIN SP European Soc Comparative Physiol & Biochem DE nutrient intake; energy balance; salmon ID MALE ATLANTIC SALMON; NEUROPEPTIDE-Y NPY; GROWTH-FACTOR-I; RAINBOW-TROUT; SALAR L; PARAVENTRICULAR NUCLEUS; SEXUAL-MATURATION; FOOD-INTAKE; ONCORHYNCHUS-MYKISS; ARCTIC CHARR AB There is a correlation between growth, adiposity and early maturity in salmonids. One strategy to avoid early maturity may be to favor muscle growth over fat accumulation. The present article discusses the regulation of food intake and fat storage under conditions of either relative over-abundance or insufficiency of energy intake in salmon. In a series of experiments with chinook salmon of equal size, food intake of fat fish was significantly less than in their lean counterparts. Furthermore, when fat and lean fish were pooled and given access to the same diet, whole body fat levels converged, suggesting a robust mechanism for regulating body fat stores. Growth of the initially fat fish was impaired relative to the initially lean fish. In separate experiments, when chinook and coho salmon were deprived of food, hypothalamic expression of neuropeptide Y (NPY)-like mRNA increased significantly compared to fed controls. Increased hypothalamic NPY mRNA and NPY secretion have been shown to be central elements of energy balance regulation in mammals. The increase in hypothalamic NPY-like:ene expression in a teleost may reflect the primitive evolution a central mechanism to regulate energy intake and expenditure that has been elucidated in mammals. (C)1999 Elsevier Science B.V. All rights reserved. C1 Univ Washington, Sch Fisheries, Seattle, WA 98195 USA. NOAA, Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, Seattle, WA 98112 USA. RP Silverstein, JT (reprint author), USDA ARS, Jamie Whitten Delta States Res Ctr, Expt Stn Rd,5 Story Bldg, Stoneville, MS 38776 USA. NR 49 TC 71 Z9 74 U1 1 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0044-8486 EI 1873-5622 J9 AQUACULTURE JI Aquaculture PD JUL 1 PY 1999 VL 177 IS 1-4 BP 161 EP 169 DI 10.1016/S0044-8486(99)00076-9 PG 9 WC Fisheries; Marine & Freshwater Biology SC Fisheries; Marine & Freshwater Biology GA 208TH UT WOS:000081007400014 ER PT J AU Trainer, VL Baden, DG AF Trainer, VL Baden, DG TI High affinity binding of red tide neurotoxins to marine mammal brain SO AQUATIC TOXICOLOGY LA English DT Article DE red tides; marine mammal; brevetoxin; saxitoxin; sodium channel; receptor binding ID SENSITIVE SODIUM-CHANNELS; SAXITOXIN BINDING; SYNAPTOSOMES; TETRODOTOXIN; SITES; BREVETOXINS; MEMBRANES; FISH AB During a period of several weeks in the spring of 1996, over 200 manatees (Trichechus manatus latirostris) were found dead or dying in coastal waters or on beaches of the Florida west coast. Concurrent with this event, high densities of Gymnodinium breve, the dinoflagellate which produces the potent neurotoxin called brevetoxin, were observed in the same coastal areas. Our study demonstrates that brevetoxin binds to isolated nerve preparations from manatee brain with similar affinity as that reported for a number of terrestrial mammals. Analysis of receptor binding of tritiated brevetoxin to manatee brain, illustrates saturable specific binding, competition of specific binding by a non-radioactive toxin of the same structure, and temperature dependence of binding. Complementary studies with the red tide neurotoxin, saxitoxin, which is responsible for the intoxication syndrome paralytic shellfish poisoning, show high affinity and specific binding of this toxin to isolated nerve preparations from several marine mammals, including manatee, gray whale (Eschrichtius robustus), humpback whale (Megaptera novaeangliae), and sea lion (Zalophus californianus). These results demonstrate the specific binding of brevetoxin and saxitoxin to excitable brain tissue of marine mammals and support the hypothesis that the exposure of manatees to brevetoxin in the spring of 1996 was a factor in their stranding and death. (C) 1999 Elsevier Science B.V. All rights reserved. C1 NOAA, Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, Environm Conservat Div, Seattle, WA 98112 USA. Univ Miami, Rosenstiel Sch Marine & Atmospher Sci, Marine & Freshwater Biomed Sci Ctr, Natl Inst Environm Hlth Sci, Miami, FL 33149 USA. RP Trainer, VL (reprint author), NOAA, Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, Environm Conservat Div, 2725 Montlake Blvd E, Seattle, WA 98112 USA. NR 31 TC 40 Z9 43 U1 3 U2 27 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0166-445X J9 AQUAT TOXICOL JI Aquat. Toxicol. PD JUL PY 1999 VL 46 IS 2 BP 139 EP 148 DI 10.1016/S0166-445X(98)00125-8 PG 10 WC Marine & Freshwater Biology; Toxicology SC Marine & Freshwater Biology; Toxicology GA 202HQ UT WOS:000080646600006 ER PT J AU Tilbury, KL Adams, NG Krone, CA Meador, JP Early, G Varanasi, U AF Tilbury, KL Adams, NG Krone, CA Meador, JP Early, G Varanasi, U TI Organochlorines in stranded pilot whales (Globicephala melaena) from the coast of Massachusetts SO ARCHIVES OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY LA English DT Article ID POLYCHLORINATED-BIPHENYLS PCBS; DOLPHINS TURSIOPS-TRUNCATUS; SEAL PHOCA-VITULINA; RESIDUE LEVELS; DELPHINAPTERUS-LEUCAS; STRIPED DOLPHIN; MARINE MAMMALS; CONTAMINANTS; TISSUES; DDT AB Pilot whales strand periodically along the U.S. coast, and these strandings offer an opportunity for the collection of tissues for biomonitoring of contaminant exposure in cetaceans, as well as for specimen archiving. Concentrations of organochlorine (OC) contaminants (e.g., PCB congeners, pesticides, DDTs) were measured in tissue samples from pilot whales that stranded in 1986 and 1990 along the Massachusetts coast. Adult and fetal samples of blubber, liver, brain, and kidney were collected, as well as ovaries from mature female whales. Many of the OCs found in maternal tissues were detected in corresponding fetal tissues indicating maternal transfer of OCs to the fetus. The concentrations of individual OCs in tissues varied considerably among the animals. Statistically significant differences were found between females and males for the concentrations of certain analytes (e.g., Sigma PCBs, p,p'-DDE) and these differences may be partially due to contaminants being transferred by the female whales during gestation and lactation. The concentrations of OCs in different tissues were similar when based on total lipid weight, except for the brain, which contained the lowest lipid-normalized OC concentrations. The low concentrations in brain may be related to the disparate lipid compositions in this tissue as well as the presence of the blood-brain barrier. The availability of data on these archived and biomonitoring samples provides a baseline for future retrospective studies. C1 NOAA, Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, Environm Conservat Div, Seattle, WA 98112 USA. New England Aquarium, Boston, MA 02110 USA. RP Tilbury, KL (reprint author), NOAA, Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, Environm Conservat Div, 2725 Montlake Blvd E, Seattle, WA 98112 USA. NR 60 TC 28 Z9 28 U1 3 U2 13 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0090-4341 J9 ARCH ENVIRON CON TOX JI Arch. Environ. Contam. Toxicol. PD JUL PY 1999 VL 37 IS 1 BP 125 EP 134 PG 10 WC Environmental Sciences; Toxicology SC Environmental Sciences & Ecology; Toxicology GA 201XZ UT WOS:000080623700015 PM 10341050 ER PT J AU Seem, JE House, JM Monroe, RH AF Seem, JE House, JM Monroe, RH TI On-line monitoring and fault detection SO ASHRAE JOURNAL LA English DT Article AB Modern energy management and control systems have alarm and trend features that allow building operators to monitor and troubleshoot building systems. The alarm feature can provide nearly immediate feedback when, for instance, a sensor value is outside specified limits. Using the trend feature, building operators can view graphs of sensor and controller output versus time. In the case of an alarm, information obtained using the trend feature can assist the operator in isolating the cause of the alarm. However, it can be difficult to select the alarm limits. If the limits are too narrow, the building control system likely will issue a number of false alarms and building operators eventually will ignore them. If the limits are too wide, faulty conditions will tend to go unnoticed because alarms are not issued. C1 Johnson Controls Inc, Milwaukee, WI 53201 USA. Natl Inst Stand & Technol, Bldg Environm Div, Bldg & Fire Res Lab, Gaithersburg, MD 20899 USA. RP Seem, JE (reprint author), Johnson Controls Inc, Milwaukee, WI 53201 USA. NR 6 TC 7 Z9 7 U1 0 U2 1 PU AMER SOC HEATING REFRIGERATING AIR-CONDITIONING ENG, INC, PI ATLANTA PA 1791 TULLIE CIRCLE NE, ATLANTA, GA 30329 USA SN 0001-2491 J9 ASHRAE J JI ASHRAE J. PD JUL PY 1999 VL 41 IS 7 BP 21 EP 26 PG 6 WC Thermodynamics; Construction & Building Technology; Engineering, Mechanical SC Thermodynamics; Construction & Building Technology; Engineering GA 235EY UT WOS:000082528300015 ER PT J AU Liu, HY Chang, WL Oltmans, SJ Chan, LY Harris, JM AF Liu, HY Chang, WL Oltmans, SJ Chan, LY Harris, JM TI On springtime high ozone events in the lower troposphere from Southeast Asian biomass burning SO ATMOSPHERIC ENVIRONMENT LA English DT Article DE tropospheric ozone; vertical profiles; Hong Kong; continental Southeast Asia; back trajectory analysis ID BEHAVIOR AB Ozone peaks with mixing ratios as high as 138 ppbv were observed in the lower troposphere (2.5-4.5 km) over Hong Kong in spring. Simultaneously observed high humidity suggests that this enhanced ozone was not the result of transport from the upper troposphere. Back trajectory analysis suggests that these enhancements resulted from lateral transport. Air masses arriving at the altitude of the ozone peaks appear to have passed over continental Southeast Asia where the bulk of biomass burning occurs at this time of the year (February-April). We hypothesize that biomass burning in this region provided the necessary precursors for the observed ozone enhancement. As far as we know this is the first observation of highly enhanced ozone layers associated with biomass burning in continental Southeast Asia. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Hong Kong Polytech Univ, Dept Civil & Struct Engn, Hong Kong, Hong Kong. NOAA, Climate Monitoring & Diagnost Lab, Boulder, CO 80303 USA. Hong Kong Observ, Hong Kong, Hong Kong. RP Liu, HY (reprint author), Harvard Univ, Dept Earth & Planetary Sci, 20 Oxford St, Cambridge, MA 02138 USA. RI Liu, Hongyu/A-5867-2008 NR 27 TC 60 Z9 65 U1 0 U2 10 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1352-2310 J9 ATMOS ENVIRON JI Atmos. Environ. PD JUL PY 1999 VL 33 IS 15 BP 2403 EP 2410 DI 10.1016/S1352-2310(98)00357-4 PG 8 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA 189BE UT WOS:000079883600010 ER PT J AU Polissar, AV Hopke, PK Paatero, P Kaufmann, YJ Hall, DK Bodhaine, BA Dutton, EG Harris, JM AF Polissar, AV Hopke, PK Paatero, P Kaufmann, YJ Hall, DK Bodhaine, BA Dutton, EG Harris, JM TI The aerosol at Barrow, Alaska: long-term trends and source locations SO ATMOSPHERIC ENVIRONMENT LA English DT Article DE atmospheric aerosol; arctic haze; factor analysis; trends; potential source contribution function ID ARCTIC AIR-POLLUTION; SEA-ICE; ATMOSPHERIC AEROSOL; METEOROLOGICAL DATA; TRAJECTORY MODELS; FLOW PATTERNS; SOUTH-POLE; SULFUR; HAZE; DECREASE AB Aerosol data consisting of condensation nuclei (CN) counts, black carbon (BC) mass, aerosol light scattering (SC), and aerosol optical depth (AOD) measured at Barrow, Alaska from 1977 to 1994 have been analyzed by three-way positive matrix factorization (PMF3) by pooling all of the different data into one large three-way array. The PMF3 analysis identified four factors that indicate four different combinations of aerosol sources active throughout the year in Alaska. Two of the factors (F1, F2) represent Arctic haze, The first Arctic hate have factor F1 is dominant in January-February while the second factor F2 is dominant in March-April. They appear to be material that is generally ascribed to long-range transported anthropogenic particles. A lower ratio of condensation nuclei to scattering coefficient loadings is obtained for F2 indicating larger particles. Factor F3 is related to condensation nuclei. It has an annual cycle with two maxima, March and July-August indicating some involvement of marine biogenic sources. The fourth factor F4 represents the contribution to the stratospheric aerosol from the eruptions of El Chichon and Mt. Pinatubo. No significant long-term trend for F1 was detected while F2 shows a negative trend over the period from 1982 to 1994 but not over the whole measurement period. A positive trend of F3 over the whole period has been observed. This trend may be related to increased biogenic sulfur production caused by reductions in the sea-ice cover in the Arctic and/or an air temperature increase in the vicinity of Barrow. Potential source contribution function (PSCF) analysis showed that in winter and spring during 1989 to 1993 regions in Eurasia and North America are the sources of particles measured at barrow. In contrast to this, large areas in the North Pacific Ocean and the Arctic Ocean was contributed to observed high concentrations of CN in the summer season. Three-way positive matrix factorization was an effective method to extract time-series information contained in the measured quantities. PSCF was useful for the identification possible source areas and the potential pathways for the Barrow aerosol. The effects of long-distance transport, photochemical aerosol production, emissions from biogenic activities in the ocean, volcanic eruptions on the aerosol measurements made at Barrow were extracted using this combined methodology. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Clarkson Univ, Dept Chem, Potsdam, NY 13699 USA. Univ Helsinki, Dept Phys, FIN-00014 Helsinki, Finland. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NOAA, Climate Monitoring & Diagnost Lab, RECGI, Boulder, CO 80303 USA. RP Hopke, PK (reprint author), Clarkson Univ, Dept Chem, Potsdam, NY 13699 USA. RI Hall, Dorothy/D-5562-2012; Hopke, Philip/C-6020-2008 OI Hopke, Philip/0000-0003-2367-9661 NR 76 TC 115 Z9 127 U1 8 U2 44 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1352-2310 J9 ATMOS ENVIRON JI Atmos. Environ. PD JUL PY 1999 VL 33 IS 16 BP 2441 EP 2458 DI 10.1016/S1352-2310(98)00423-3 PG 18 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA 191MW UT WOS:000080027000001 ER PT J AU Williams, E Boldi, B Matlin, A Weber, M Hodanish, S Sharp, D Goodman, S Raghavan, R Buechler, D AF Williams, E Boldi, B Matlin, A Weber, M Hodanish, S Sharp, D Goodman, S Raghavan, R Buechler, D TI The behavior of total lightning activity in severe Florida thunderstorms SO ATMOSPHERIC RESEARCH LA English DT Article DE total lightning activity; thunderstorms; Florida ID CHARGE; ELECTRIFICATION; THUNDERCLOUDS; CLOUDS; RADAR; STATE AB The development of a new observational system called LISDAD (Lightning Imaging Sensor Demonstration and Display) has enabled a study of severe weather in central Florida. The total flash rates for storms verified to be severe are found to exceed 60 fpm, with some values reaching 500 fpm. Similar to earlier results for thunderstorm microbursts, the peak flash rate precedes the severe weather at the ground by 5-20 min. A distinguishing feature of severe storms is the presence of lightning 'jumps' - abrupt increases in flash rate in advance of the maximum rate for the storm. The systematic total lightning precursor to severe weather of all kinds - wind, hail, tornadoes - is interpreted in terms of the updraft that sows the seeds aloft for severe weather at the surface and simultaneously stimulates the ice microphysics that drives the intracloud lightning activity. (C) 1999 Elsevier Science B.V. All rights reserved. C1 MIT, Ralph M Parsons Lab, Cambridge, MA 02139 USA. MIT, Lincoln Lab, Lexington, MA 02420 USA. Natl Weather Serv, Melbourne, FL 32935 USA. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35806 USA. RP Williams, E (reprint author), MIT, Ralph M Parsons Lab, 77 Massachusetts Ave, Cambridge, MA 02139 USA. NR 42 TC 114 Z9 128 U1 5 U2 15 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 USA SN 0169-8095 J9 ATMOS RES JI Atmos. Res. PD JUL PY 1999 VL 51 IS 3-4 BP 245 EP 265 DI 10.1016/S0169-8095(99)00011-3 PG 21 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 221QE UT WOS:000081737100006 ER PT J AU Bateman, MG Eack, KB Rust, WD Marshall, TC AF Bateman, MG Eack, KB Rust, WD Marshall, TC TI Electrical current along balloon rigging line inside thunderstorms SO ATMOSPHERIC RESEARCH LA English DT Article DE electrical current; balloon; rigging line; thunderstorm ID PRECIPITATION; FIELD AB We have designed a new instrument to measure the current flowing along balloon rigging line during flights through thunderstorms. This instrument was tested in a high voltage facility and used to collect line current data during one balloon flight into a thunderstorm. Using these data, worst-case calculations are made; as such, we claim that they are the upper limits of any alteration (to the measured electric field or particle charge) that may occur, and the real number is Likely much less. It is postulated the rigging-line current could have two separate effects on the measured electric field: (1) reduction of the field due to emission of corona ions, and (2) enhancement of the field due to the insertion of a long thin 'conductor.' Even with current as high as 1 IJ A (the largest measured was around 50-100 nA), these two effects were found to be about -1% and +1%, respectively. Also, the calculated worst-case alteration to charged precipitation measurements is about 0.1 pC. Thus, with proper efforts to make the rigging Line as poor a conductor as possible, it seems that we are justified in stating that these effects are negligible. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Langmuir Lab Atmospher Res, Socorro, NM USA. Univ Calif Los Alamos Natl Lab, Space & Atmospher Sci Grp, Los Alamos, NM USA. Natl Severe Storms Lab, Norman, OK 73069 USA. Univ Mississippi, Dept Phys & Astron, University, MS 38677 USA. RP Bateman, MG (reprint author), NASA, George C Marshall Space Flight Ctr, Univ Space Res Assoc, 977 Explorer Blvd, Huntsville, AL 35806 USA. NR 13 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 USA SN 0169-8095 J9 ATMOS RES JI Atmos. Res. PD JUL PY 1999 VL 51 IS 3-4 BP 323 EP 335 DI 10.1016/S0169-8095(99)00017-4 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 221QE UT WOS:000081737100012 ER PT J AU Harwell, MA Myers, V Young, T Bartuska, A Gassman, N Gentile, JH Harwell, CC Appelbaum, S Barko, J Causey, B Johnson, C McLean, A Smola, R Templet, P Tosini, S AF Harwell, MA Myers, V Young, T Bartuska, A Gassman, N Gentile, JH Harwell, CC Appelbaum, S Barko, J Causey, B Johnson, C McLean, A Smola, R Templet, P Tosini, S TI A framework for an ecosystem integrity report card SO BIOSCIENCE LA English DT Article ID SOUTH FLORIDA; MANAGEMENT C1 Univ Miami, Ctr Marine & Environm Anal, Miami, FL 33149 USA. Environm Def Fund, Oakland, CA 94618 USA. World Wildlife Def Fund, Washington, DC 20037 USA. ARS, Forest Hlth Protect, USDA, Washington, DC 20250 USA. Broward Cty Dept Nat Resources, Ft Lauderdale, FL 33301 USA. Harwell Gentile & Associates LC, Coconut Grove, FL 33133 USA. USA, Ecosyst Restorat Sect, Corps Engineers, Jacksonville, FL 32232 USA. USA, Corps Engineers, Waterways Expt Stn, Vicksburg, MS 39180 USA. Florida State Univ, Tallahassee, FL 32306 USA. Florida Keys Natl Marine Sanctuary, Marathon, FL 33050 USA. S Florida Water Management Dist, W Palm Beach, FL 33416 USA. Natl Resources Conservat Serv, Dept Agr, W Palm Beach, FL 33416 USA. Louisiana State Univ, Inst Environm Studies, Baton Rouge, LA 70803 USA. RP Harwell, MA (reprint author), Univ Miami, Ctr Marine & Environm Anal, Miami, FL 33149 USA. NR 44 TC 40 Z9 47 U1 1 U2 13 PU AMER INST BIOLOGICAL SCI PI WASHINGTON PA 1444 EYE ST, NW, STE 200, WASHINGTON, DC 20005 USA SN 0006-3568 J9 BIOSCIENCE JI Bioscience PD JUL PY 1999 VL 49 IS 7 BP 543 EP 556 DI 10.2307/1313475 PG 14 WC Biology SC Life Sciences & Biomedicine - Other Topics GA 212HQ UT WOS:000081211600008 ER PT J AU Sluka, RD Miller, MW AF Sluka, RD Miller, MW TI Status of crown-of-thorns starfish in Laamu Atoll, Republic of Maldives SO BULLETIN OF MARINE SCIENCE LA English DT Article ID ACANTHASTER-PLANCI AB Qualitative and quantitative surveys of crown-of-thorns starfish (Acanthaster planci) abundance were conducted in Laamu Atoll, Republic of Maldives. Abundance was low, with starfish most abundant in shallow-water Acropora formosa patch reefs. Juvenile starfish were observed on reef crests on the outside of the atoll rim while adults were found on patch reefs. Starfish were also observed on one fare reef flat. Based upon the available data (including unpublished government reports), it appears that there are no crown-of-thorns outbreaks occurring in the Maldives. Given the dispersed nature of this island country and thus the difficulty in monitoring all coral reefs, outbreaks could occur in more remote areas not generally visited by those able to recognize the importance of recording these occurrences. C1 REpubl Maldives & Wildlife Conservat Soc, Oceanog Soc Maldives, Bronx, NY 10460 USA. Natl Marine Fisheries Serv, SE Fisheries Sci Ctr, Miami, FL 33149 USA. RP Sluka, RD (reprint author), 10852 N Kendall Dr 205, Miami, FL 33176 USA. NR 7 TC 0 Z9 0 U1 2 U2 8 PU ROSENSTIEL SCH MAR ATMOS SCI PI MIAMI PA 4600 RICKENBACKER CAUSEWAY, MIAMI, FL 33149 USA SN 0007-4977 J9 B MAR SCI JI Bull. Mar. Sci. PD JUL PY 1999 VL 65 IS 1 BP 253 EP 258 PG 6 WC Marine & Freshwater Biology; Oceanography SC Marine & Freshwater Biology; Oceanography GA 216BJ UT WOS:000081420400018 ER PT J AU Grice, GK Trapp, RJ Corfidi, SF Davies-Jones, R Buonanno, CC Craven, JP Droegemeier, KK Duchon, C Houghton, JV Prentice, RA Romine, G Schlachter, K Wagner, KK AF Grice, GK Trapp, RJ Corfidi, SF Davies-Jones, R Buonanno, CC Craven, JP Droegemeier, KK Duchon, C Houghton, JV Prentice, RA Romine, G Schlachter, K Wagner, KK TI The golden anniversary celebration of the first tornado forecast SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Editorial Material C1 NOAA, NWS, NCEP, Storm Predict Ctr,Forecast Off, Norman, OK 73069 USA. NOAA, ERL, Natl Severe Storms Lab, Boulder, CO 80303 USA. NOAA, Environm Res Lab, Natl Severe Storms Lab, Norman, OK 73069 USA. Univ Oklahoma, Sch Meteorol, Norman, OK 73019 USA. Univ Oklahoma, Ctr Anal & Predict Storms, Norman, OK 73019 USA. 72nd Operat Support Squadron Operat Support Weath, Tinker AFB, OK USA. Fed Aviat Adm Acad, Oklahoma City, OK USA. RP Corfidi, SF (reprint author), NOAA, NWS, NCEP, Storm Predict Ctr,Forecast Off, 1313 Halley Circle, Norman, OK 73069 USA. NR 0 TC 4 Z9 4 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 1999 VL 80 IS 7 BP 1341 EP 1348 DI 10.1175/1520-0477(1999)080<1341:TGACOT>2.0.CO;2 PG 8 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 221LG UT WOS:000081728100001 ER PT J AU Anderson, J van den Dool, H Barnston, A Chen, W Stern, W Ploshay, J AF Anderson, J van den Dool, H Barnston, A Chen, W Stern, W Ploshay, J TI Present-day capabilities of numerical and statistical models for atmospheric extratropical seasonal simulation and prediction SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article ID SOUTHERN OSCILLATION CYCLE; NORTHERN-HEMISPHERE; FORECAST SYSTEM; SKILL; PREDICTABILITY; CIRCULATION; INTEGRATIONS; TEMPERATURE; ANOMALIES; AMIP AB A statistical model and extended ensemble integrations of two atmospheric general circulation models (GCMs) are used to simulate the extratropical atmospheric response to forcing by observed SSTs for the years 1980 through 1988. The simulations are compared to observations using the anomaly correlation and root-mean-square error of the 700-hPa height field over a region encompassing the extratropical North Pacific Ocean and most of North America. On average, the statistical model is found to produce considerably better simulations than either numerical model, even when simple statistical corrections are used to remove systematic errors from the numerical model simulations. In the mean, the simulation skill is low, but there are some individual seasons for which all three models produce simulations with good skill. An approximate upper bound to the simulation skill that could be expected from a GCM ensemble, if the model's response to SST forcing is assumed to be perfect, is computed. This perfect model predictability allows one to make some rough extrapolations about the skill that could be expected if one could greatly improve the mean response of the GCMs without significantly impacting the variance of the ensemble. These perfect model predictability skills are better than the statistical model simulations during the summer, but for the winter, present-day statistical forecasts already have skill, that is as high as the upper bound for the GCMs. Simultaneous improvements to the GCM mean response and reduction in the GCM ensemble variance would be required for these GCMs to do significantly better than the statistical model in winter. This does not preclude the possibility that, as is presently the case, a statistical blend of GCM and statistical predictions could produce a simulation better than either alone. Because of the primitive state of coupled ocean-atmosphere GCMs, the vast majority of seasonal predictions currently produced by GCMs are performed using a two-tiered approach in which SSTs are first predicted and then used to force an atmospheric model; this motivates the examination of the simulation problem. However, it is straightforward to use the statistical model to produce true forecasts by changing its predictors from simultaneous to precursor SSTs. An examination of the decrease in skill of the statistical model when changed from simulation to prediction mode is extrapolated to draw conclusions about the skill to be expected from good coupled GCM predictions. C1 Princeton Univ, Geophys Fluid Dynam Lab, Princeton, NJ 08542 USA. Natl Ctr Environm Predict, Climate Predict Ctr, Camp Springs, MD USA. RP Anderson, J (reprint author), Princeton Univ, Geophys Fluid Dynam Lab, POB 308, Princeton, NJ 08542 USA. NR 40 TC 73 Z9 75 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 1999 VL 80 IS 7 BP 1349 EP 1361 DI 10.1175/1520-0477(1999)080<1349:PDCONA>2.0.CO;2 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 221LG UT WOS:000081728100002 ER PT J AU Langland, RH Toth, Z Gelaro, R Szunyogh, I Shapiro, MA Majumdar, SJ Morss, RE Rohaly, GD Velden, C Bond, N Bishop, CH AF Langland, RH Toth, Z Gelaro, R Szunyogh, I Shapiro, MA Majumdar, SJ Morss, RE Rohaly, GD Velden, C Bond, N Bishop, CH TI The North Pacific Experiment (NORPEX-98): Targeted observations for improved North American weather forecasts SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article ID SINGULAR VECTORS; ADAPTIVE OBSERVATIONS; INITIAL CONDITIONS; SENSITIVITY; ENSEMBLE; IMPACT; SYSTEM; ERRORS; NCEP; FASTEX AB The objectives and preliminary results of an interagency field program, the North Pacific Experiment (NORPEX), which took place between 14 January and 27 February 1998, are described. NORPEX represents an effort to directly address the issue of observational sparsity over the North Pacific basin, which is a major contributing factor in short-range (less than 4 days) forecast failures for land-falling Pacific winter-season storms that affect the United States, Canada, and Mexico. The special observations collected in NORPEX include approximately 700 targeted tropospheric soundings of temperature, wind, and moisture from Global Positioning System (GPS) dropsondes obtained in 38 storm reconnaissance missions using aircraft based primarily in Hawaii and Alaska. In addition, wind data were provided every 6 h over the entire North Pacific during NORPEX, using advanced and experimental techniques to extract information from multispectral geostationary satellite imagery. Preliminary results of NORPEX data impact studies using the U.S. Navy and National Weather Service forecast models include reductions of approximately 10% in mean 2-day forecast error over western North America (30 degrees-60 degrees N, 100 degrees-130 degrees W) from assimilation of targeted dropsonde and satellite wind data (when measured against control forecasts that contain no special NORPEX observations). There are local reductions of up to 50% in 2-day forecast error for individual cases, although some forecasts are degraded by the addition of the special dropsonde or satellite wind data. In most cases, the positive impact of the targeted dropsonde data on short-range forecast skill is reduced when the full set of advanced satellite wind data is already included in the model analyses. The NORPEX dataset is being used in research to improve objective methods for targeting observations, to study the "mix" of in situ and space-based observations, and to understand the structure and dynamics of fast-growing errors that Limit our ability to provide more accurate forecasts of Pacific winter storms. C1 USN, Res Lab, Marine Meteorol Div, Monterey, CA 93943 USA. NCEP, Camp Springs, MD USA. NOAA, ETL, Boulder, CO 80303 USA. Penn State Univ, Dept Meteorol, University Pk, PA 16802 USA. MIT, Dept Earth Atmospher & Planetary Sci, Cambridge, MA 02139 USA. Univ Wisconsin, CIMSS, Madison, WI USA. Univ Washington, JISAO, Seattle, WA 98195 USA. RP Langland, RH (reprint author), USN, Res Lab, Marine Meteorol Div, 7 Grace Hopper Ave, Monterey, CA 93943 USA. RI Szunyogh, Istvan/G-9248-2012; Toth, Zoltan/I-6624-2015 OI Toth, Zoltan/0000-0002-9635-9194 NR 41 TC 117 Z9 129 U1 0 U2 8 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 1999 VL 80 IS 7 BP 1363 EP 1384 DI 10.1175/1520-0477(1999)080<1363:TNPENT>2.0.CO;2 PG 22 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 221LG UT WOS:000081728100003 ER PT J AU Barsugli, JJ Whitaker, JS Loughe, AF Sardeshmukh, PD Toth, Z AF Barsugli, JJ Whitaker, JS Loughe, AF Sardeshmukh, PD Toth, Z TI The effect of the 1997/98 El Nino on individual large-scale weather events SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article ID OSCILLATION; GENERATION; IMPACT; NMC AB Can an individual weather event be attributed to El Nino? This question is addressed quantitatively using ensembles? of medium-range weather forecasts made with and without tropical sea surface temperature anomalies. The National Centers for Environmental Prediction (NCEP) operational medium-range forecast model is used. It is found that anomalous tropical forcing affects forecast skill in midlatitudes as early as the fifth day of the forecast. The effect of the anomalous sea surface temperatures in the medium range is defined as the synoptic El Nino signal. The synaptic El Nino signal over North America is found to vary from case to case and sometimes can depart dramatically from the pattern classically associated with El Nino. This method of parallel ensembles of medium-range forecasts provides information about the changing impacts of El Nino on timescales of a week or two that is not available from conventional seasonal forecasts. Knowledge of the synoptic El Nino signal can be used to attribute aspects of individual weather events to EI Nino. Three large-scale weather events are discussed in detail: the January 1998 ice storm in the northeastern United States and southeastern Canada, the February 1998 rains in central and southern California, and the October 1997 blizzard in Colorado. Substantial impacts of El Nino are demonstrated in the first two cases. The third case is inconclusive. C1 NOAA, CIRES, Climate Diagnost Ctr, Boulder, CO 80303 USA. NOAA, NCEP, EMC, Washington, DC 20233 USA. RP Barsugli, JJ (reprint author), Univ Colorado, CIRES, Campus Box 216, Boulder, CO 80309 USA. RI Barsugli, Joseph/K-3541-2015; Toth, Zoltan/I-6624-2015 OI Barsugli, Joseph/0000-0002-3078-6396; Toth, Zoltan/0000-0002-9635-9194 NR 11 TC 35 Z9 35 U1 0 U2 9 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 1999 VL 80 IS 7 BP 1399 EP 1411 DI 10.1175/1520-0477(1999)080<1399:TEOTEN>2.0.CO;2 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 221LG UT WOS:000081728100005 ER PT J AU Molinari, RL AF Molinari, RL TI Lessons learned from operating global ocean observing networks SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article ID SURFACE AB The Global Ocean Observing System Center (GOOSC) at the National Oceanic and Atmospheric Administration's (NOAA) Atlantic Oceanographic and Meteorological Laboratory operates two global observing networks, a drifting buoy array, and a Voluntary Observing Ship network. The arrays provide in real time surface atmospheric and subsurface oceanographic data needed by NOAA weather and climate forecasters. The data are used in delayed mode to verify model simulations of the ocean and atmosphere, to provide in situ calibration/validation data for remote sensing observations, and to increase understanding of the dynamics of the ocean and atmosphere. The operational and research les sons learned in the operation of the GOOSC are reviewed. Operationally, it was learned that, because of costs, international participation is required to maintain global networks; data management methodology is a critical component of operations; and integrated observing systems using multiple platforms provide more accurate products. Scientifically, it was learned, for example, that accurate characterizations of the salinity field must be available in model simulations. As more data become available it is found that scales of important phenomena such as equatorial upwelling are smaller, and high-frequency signals can impact on the mean structure of the upper ocean. These findings must be considered when designing effective sampling strategies. C1 NOAA, Atlantic Oceanog & Meteorol Lab, Miami, FL 33149 USA. RP Molinari, RL (reprint author), NOAA, Atlantic Oceanog & Meteorol Lab, 4301 Rickenbacker Causeway, Miami, FL 33149 USA. NR 9 TC 3 Z9 3 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 1999 VL 80 IS 7 BP 1413 EP 1419 DI 10.1175/1520-0477(1999)080<1413:LLFOGO>2.0.CO;2 PG 7 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 221LG UT WOS:000081728100006 ER PT J AU Knutson, TR Tuleya, RE AF Knutson, TR Tuleya, RE TI Increased hurricane intensities with CO2-induced warming as simulated using the GFDL hurricane prediction system SO CLIMATE DYNAMICS LA English DT Article ID SEA-SURFACE TEMPERATURE; TROPICAL CYCLONE INTENSITY; EXISTING CLIMATE MODELS; MAXIMUM INTENSITY; ANTHROPOGENIC CHANGES; ATLANTIC HURRICANES; NUMERICAL-MODEL; SENSITIVITY; FREQUENCY; ATMOSPHERE AB The impact of CO2-induced global warming on the intensities of strong hurricanes is investigated using the GFDL regional high-resolution hurricane prediction system. The large-scale initial conditions and boundary conditions for the regional model experiments, including SSTs, are derived from control and transient CO2 increase experiments with the GFDL R30-resolution global coupled climate model. In a case study approach, 51 northwest Pacific storm cases derived from the global model under present-day climate conditions are simulated with the regional model, along with 51 storm cases for high CO2 conditions. For each case, the regional model is integrated forward for five days without ocean coupling. The high CO2 storms, with SSTs warmer by about 2.2 degrees C on average and higher environmental convective available potential energy (CAPE), are more intense than the control storms by about 3-7 m/s (5%-11%) for surface wind speed and 7 to 24 hPa for central surface pressure. The simulated intensity increases are statistically significant according to most of the statistical tests conducted and are robust to changes in storm initialization methods. Near-storm precipitation is 28% greater in the high CO2 sample. In terms of storm tracks, the high CO2 sample is quite similar to the control. The mean radius of hurricane force winds is 2 to 3% greater for the composite high CO2 storm than for the control, and the high CO2 storms penetrate slightly higher into the upper troposphere. More idealized experiments were also performed in which an initial storm disturbance was embedded in highly simplified flow fields using time mean temperature and moisture conditions from the global climate model. These idealized experiments support the case study results and suggest that, in terms of thermodynamic influences, the results for the NW Pacific basin are qualitatively applicable to other tropical storm basins. C1 NOAA, Geophys Fluid Dynam Lab, Princeton, NJ 08542 USA. RP Knutson, TR (reprint author), NOAA, Geophys Fluid Dynam Lab, POB 308, Princeton, NJ 08542 USA. NR 54 TC 73 Z9 78 U1 0 U2 10 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 JUL PY 1999 VL 15 IS 7 BP 503 EP 519 DI 10.1007/s003820050296 PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 220EM UT WOS:000081651600002 ER PT J AU Womeldorf, C Grosshandler, W AF Womeldorf, C Grosshandler, W TI Flame extinction limits in CH2F2/air mixtures SO COMBUSTION AND FLAME LA English DT Article ID PREMIXED FLAMES; FLAMMABILITY AB To optimize the efficiency and safety of mixtures of nonozone-depleting refrigerant replacements, precise measurements of the lean flammability limits of pure refrigerants and the critical flammability ratio of their mixtures are crucial. Current test methods that model the accidental ignition of a volume of premixed fuel and air provide ambiguous results when measuring the limiting behavior of weakly flammable refrigerants. An alternative approach using the extrapolation of the global extinction stretch rates to zero as measured in a premixed counterflow burner has been tested. In this work the approach, accuracy, and precision of the technique as it applies to CH2F2 (difluoromethane, R-32) are presented. Comparisons are made to the behavior of CH4 in the same burner and to published data on the lean limiting equivalence ratio, Phi(0). The lean flammability limit of CH2F2 in dry air is found to be Phi(0) = 0.78 +/- 0.04. Concurrent computational modeling of the combustion of a one-dimensional, unstrained flame of CH2F2 in air, individually and in mixtures with CH4, has been performed. Initial estimates of the laminar flame speed for CH2F2/air mixtures from stoichiometric to lean are reported and interpreted in light of the experimental results. (C) 1999 by The Combustion Institute. C1 Natl Inst Stand & Technol, Bldg & Fire Res Lab, Gaithersburg, MD 20899 USA. RP Womeldorf, C (reprint author), Natl Inst Stand & Technol, Bldg & Fire Res Lab, Gaithersburg, MD 20899 USA. NR 31 TC 11 Z9 11 U1 1 U2 11 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 1999 VL 118 IS 1-2 BP 25 EP 36 DI 10.1016/S0010-2180(98)00138-2 PG 12 WC Thermodynamics; Energy & Fuels; Engineering, Multidisciplinary; Engineering, Chemical; Engineering, Mechanical SC Thermodynamics; Energy & Fuels; Engineering GA 195BP UT WOS:000080229500004 ER PT J AU Beichl, I Sullivan, F AF Beichl, I Sullivan, F TI Pay me now or pay me later SO COMPUTING IN SCIENCE & ENGINEERING LA English DT Article C1 Natl Inst Stand & Technol, Informat Technol Lab, Gaithersburg, MD 20899 USA. Inst Def Anal, Ctr Comp Sci, Bowie, MD 20715 USA. RP Beichl, I (reprint author), Natl Inst Stand & Technol, Informat Technol Lab, Gaithersburg, MD 20899 USA. NR 2 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 JUL-AUG PY 1999 VL 1 IS 4 BP 59 EP 62 DI 10.1109/5992.774841 PG 4 WC Computer Science, Interdisciplinary Applications SC Computer Science GA 211DZ UT WOS:000081145800011 ER PT J AU Lohrenz, SE Fahnenstiel, GL Redalje, DG Lang, GA Dagg, MJ Whitledge, TE Dortch, Q AF Lohrenz, SE Fahnenstiel, GL Redalje, DG Lang, GA Dagg, MJ Whitledge, TE Dortch, Q TI Nutrients, irradiance, and mixing as factors regulating primary production in coastal waters impacted by the Mississippi River plume SO CONTINENTAL SHELF RESEARCH LA English DT Article DE primary production; nutrients; phytoplankton; Mississippi river; Gulf of Mexico; eutrophication; fronts; mixing; light limitation; nutrient limitation ID GULF-OF-MEXICO; PHYTOPLANKTON PRODUCTION; CONTINENTAL-SHELF; CHESAPEAKE BAY; SURFACE WATERS; NITROGEN; ESTUARY; EUTROPHICATION; FATE; LIMITATION AB Relationships among primary production, chlorophyll, nutrients, irradiance and mixing processes were examined along the salinity gradient in the Mississippi River outflow region. A series of six cruises were conducted during 1988-1992 at various times of year and stages of river discharge. Maximum values of biomass and primary production were typically observed at intermediate salinities and coincided with non-conservative decreases in nutrients along the salinity gradient. Highest values of productivity (>10 gC m(-2) d(-1)) and biomass (>30 mg chlorophyll a m(-3)) were observed in April 1988, July-August 1990 and April-May 1992; values were lower in March and September 1991. Rates of primary production were apparently constrained by low irradiance and mixing in the more turbid, low salinity regions of the plume, and by nutrient limitation outside the plume. Highest values of primary production occurred at stations where surface nutrient concentrations exhibited large deviations from conservative mixing relationships, indicating that depletion of nutrients was related to phytoplankton uptake. Mixing and advection were important in determining the location and magnitude of primary production maxima and nutrient depletion. In addition to growth within plume surface waters, enhanced growth and/or retention of biomass may have occurred in longer residence time waters at the plume edge and/or beneath the surface plume. Vertical structure of some plume stations revealed the presence of subsurface biomass maxima in intermediate salinity water that was depleted in nutrients presumably by uptake processes. Exchange between subsurface water and the surface plume apparently contributed to the reduction in nutrients at intermediate salinities in the surface layer. DIN (= nitrate + nitrite + ammonium) : PO4 ( = phosphate) ratios in river water varied seasonally, with high values in winter and spring and low values in late summer and fall. Periods of high DIN : PO4 ratios in river nutrients coincided with cruises when surface nutrient concentrations and their ratios indicated a high probability for P limitation. N limitation was more likely to occur at high salinities and during late summer and fall. Evidence for Si limitation was also found, particularly in spring. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Univ So Mississippi, Dept Marine Sci, Stennis Space Ctr, MS 39529 USA. NOAA, Great Lakes Enviornm Res Lab, Muskegon, MI 49441 USA. NOAA, Great Lakes Environm Res Lab, Ann Arbor, MI 48105 USA. Louisiana Univ Marine Consortium, Chauvin, LA 70344 USA. Univ Alaska, Inst Marine Sci, Fairbanks, AK 99775 USA. RP Lohrenz, SE (reprint author), Univ So Mississippi, Dept Marine Sci, Stennis Space Ctr, MS 39529 USA. OI Lohrenz, Steven/0000-0003-3811-2975 NR 75 TC 184 Z9 188 U1 5 U2 48 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0278-4343 J9 CONT SHELF RES JI Cont. Shelf Res. PD JUL PY 1999 VL 19 IS 9 BP 1113 EP 1141 DI 10.1016/S0278-4343(99)00012-6 PG 29 WC Oceanography SC Oceanography GA 211DH UT WOS:000081144300001 ER PT J AU Fisher, SW Hwang, H Atanasoff, M Landrum, PF AF Fisher, SW Hwang, H Atanasoff, M Landrum, PF TI Lethal body residues for pentachlorophenol in zebra mussels (Dreissena polymorpha) under varying conditions of temperature and pH SO ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY LA English DT Article DE critical body residue; zebra mussels; pentachlorophenol; toxicokinetics ID CHIRONOMUS-RIPARIUS; ACUTE TOXICITY; ACCUMULATION; FISH; GOLDFISH; BIOCONCENTRATION; TOXICOKINETICS; CHLOROPHENOLS; METABOLISM; MIDGE AB Pentachlorophenol (PCP) toxicity was measured in the zebra mussel under varying conditions of pH (6.5, 7.5, or 8.5) and temperature (10, 17, or 25 degrees C). Toxicity decreased significantly with increasing pH at all temperatures. At a given pH level, toxicity increased significantly with increasing temperature. PCP was most toxic at pH 6.5, 25 degrees C and least toxic at pH 8.5, 10 degrees C. Toxicokinetic parameters were determined at trace PCP concentrations under each combination of pH and temperature. Increasing temperature generally increased the PCP uptake clearance (k(u)) although elimination rate constants (k(d)) were unaffected. The effect of pH on toxicokinetic parameters was inconsistent but k(u) tended to decrease as pH and ionization of PCP increased. Lethal body residues (LR(50)s), estimated from kinetic parameters determined at trace PCP concentrations and the LC50 values, varied by a factor of 122 as a function of environmental conditions while LC(50)s varied by a factor of 381. LR(50)s were also estimated from the measured PCP tissue concentrations and varied by a factor of 8 across conditions. Calculated LR(50)s were always higher than measured LR(50)s, determined under identical conditions, by at least a factor of five. However, when LR50, values were recalculated using k(u), values measured at the LC25 concentration, the resulting adjusted LR(50)s, varied only by a factor of 2.5 across the range of conditions studied and were more consistent with measured LR50 values. Thus, variance in the PCP concentration required to produce toxicity is reduced when LR(50)s are used in place of LC(50)s. Further, the method by which lethal residues (LR50 values) are determined can significantly affect the results and their interpretation. (C) 1999 Academic Press. C1 Ohio State Univ, Dept Entomol, Columbus, OH 43210 USA. Ohio State Univ, Environm Sci Program, Columbus, OH 43210 USA. NOAA, Great Lakes Environm Res Lab, Ann Arbor, MI 48105 USA. RP Fisher, SW (reprint author), Ohio State Univ, Dept Entomol, 1735 Neil Ave, Columbus, OH 43210 USA. NR 35 TC 41 Z9 44 U1 2 U2 10 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0147-6513 J9 ECOTOX ENVIRON SAFE JI Ecotox. Environ. Safe. PD JUL PY 1999 VL 43 IS 3 BP 274 EP 283 DI 10.1006/eesa.1999.1789 PG 10 WC Environmental Sciences; Toxicology SC Environmental Sciences & Ecology; Toxicology GA 210PH UT WOS:000081113500006 PM 10381305 ER PT J AU Fleischmann, CM McGrattan, KB AF Fleischmann, CM McGrattan, KB TI Numerical and experimental gravity currents related to backdrafts SO FIRE SAFETY JOURNAL LA English DT Article AB In order to clarify the mixing that occurs in a gravity current which precedes a backdraft, a two-dimensional simulation, a series of salt water experiments, and backdraft experiments were performed. A compartment in a ratio width/height/length of 1/1/2 is used in the experiments and computations. Two different openings were used in the salt water experiments and numerical computations: a fully open end wall and a h(1)/3 horizontal slot centred in an end wall, where h(1) is the compartment height. For the backdraft experiments only the h(1)/3 horizontal slot was used. The visual observations from the salt water experiments compare well with the numerical simulation. Both show a small mixed region at the gravity current shear interface for the fully open wall and mixing throughout the entire current for the h(1)/3 horizontal slot. Quantitative comparisons are made in terms of the normalised density differences, beta = (rho(0)-rho(1))/rho(1), where rho(0) is the higher density and rho(1) is the lower density. The transit time results, i.e., time between opening the compartment and the time the gravity current reaches the wall opposite the opening, for the computations compared favourably with the transit times from the salt water experiments, over the range 0.003 < beta < 0.100. Velocity measurements from the opening of the backdraft compartment, prior to ignition, also are favourable with the numerical simulation. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Univ Canterbury, Dept Civil Engn, Christchurch 1, New Zealand. NIST, Bldg & Fire Res Lab, Gaithersburg, MD 20899 USA. RP Fleischmann, CM (reprint author), Univ Canterbury, Dept Civil Engn, Christchurch 1, New Zealand. NR 12 TC 27 Z9 31 U1 0 U2 0 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0379-7112 J9 FIRE SAFETY J JI Fire Saf. J. PD JUL PY 1999 VL 33 IS 1 BP 21 EP 34 DI 10.1016/S0379-7112(98)00046-0 PG 14 WC Engineering, Civil; Materials Science, Multidisciplinary SC Engineering; Materials Science GA 220VY UT WOS:000081689600003 ER PT J AU Moore, JA AF Moore, JA TI Deep-sea finfish fisheries: Lessons from history SO FISHERIES LA English DT Article AB Recently, the depletion and increased regulation of shallow-water fishery resources have generated greater interest in the potential of deepwater fisheries. Smaller-scale fisheries for deep-sea animals have been conducted in certain locations around the world for more than a century, but large-scale commercial deepwater fisheries are a more recent phenomenon An examination of past and current deepwater fisheries shows what we can expect from the development of new fisheries targeting unexploited deep-sea resources. Previous deepwater fisheries exhibit a pattern of rapid development, depletion of the resource, and very slow recovery. If future deepwater fisheries are to avoid this fate, development of new fisheries will require a better understanding of the resource, its relationship to the environment, and a precautionary approach to resource management. RP Moore, JA (reprint author), Natl Marine Fisheries Serv, 166 Water St, Woods Hole, MA 02543 USA. RI Moore, Jon/A-5959-2008; OI Moore, Jon/0000-0002-0053-3347 NR 43 TC 14 Z9 14 U1 1 U2 10 PU AMER FISHERIES SOC PI BETHESDA PA 5410 GROSVENOR LANE SUITE 110, BETHESDA, MD 20814-2199 USA SN 0363-2415 J9 FISHERIES JI Fisheries PD JUL PY 1999 VL 24 IS 7 BP 16 EP 21 DI 10.1577/1548-8446(1999)024<0016:DFFLFH>2.0.CO;2 PG 6 WC Fisheries SC Fisheries GA 212PT UT WOS:000081226000004 ER PT J AU Moore, JA Mace, PM AF Moore, JA Mace, PM TI Challenges and prospects for deep-sea finfish fisheries SO FISHERIES LA English DT Article ID HOPLOSTETHUS-ATLANTICUS; ORANGE ROUGHY; POPULATION; GROWTH C1 Natl Marine Fisheries Serv, Woods Hole, MA 02543 USA. RP Moore, JA (reprint author), Natl Marine Fisheries Serv, 166 Water St, Woods Hole, MA 02543 USA. RI Moore, Jon/A-5959-2008; OI Moore, Jon/0000-0002-0053-3347 NR 11 TC 6 Z9 6 U1 0 U2 2 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 JUL PY 1999 VL 24 IS 7 BP 22 EP 23 PG 2 WC Fisheries SC Fisheries GA 212PT UT WOS:000081226000005 ER PT J AU Bertignac, M Hampton, J Coan, AL AF Bertignac, M Hampton, J Coan, AL TI Estimates of exploitation rates for north Pacific albacore, Thunnus alalunga, from tagging data SO FISHERY BULLETIN LA English DT Article ID TUNA KATSUWONUS-PELAMIS AB North Pacific albacore tagging data from a tag-release program conducted from 1971 to 1989 were analyzed to obtain estimates of exploitation rates and related parameters. The major albacore fishing fleets in the North Pacific, the U.S. baitboat, Japan baitboat, troll and longline fleets were used in the analysis. Another category of fleet ("other") that combined remaining miscellaneous recapture sources was also used. Tag-attrition models incorporating variable availability of tagged albacore to the various fleets, seasonal catchability, and multiyear effects on catchability were developed and applied. The incorporation of all three effects was found to improve model fit significantly. If exploitation of the tagged population is representative of the North Pacific albacore population as a whole and if tag reporting rates were high, the results would suggest that the exploitation rate has been less than 10% per year since the early 1970s. However, a deficit of returns from the troll fleet in comparison with its catch suggested that the pattern of exploitation of the tagged population, by this fleet at least, was different from that for the untagged albacore population. After compensating for assumed depressed availability of tagged albacore to the troll fleet, annual exploitation rates were estimated to have declined from a high of 40% in the mid-1970s to <10% since the early 1980s. C1 Secretariat Pacific Community, Noumea 98848, New Caledonia. SW Fisheries Sci Ctr, La Jolla, CA 92038 USA. RP Bertignac, M (reprint author), Secretariat Pacific Community, BP D5, Noumea 98848, New Caledonia. RI Bertignac, Michel/F-9177-2010 NR 17 TC 11 Z9 11 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 1999 VL 97 IS 3 BP 421 EP 433 PG 13 WC Fisheries SC Fisheries GA 216GH UT WOS:000081432700002 ER PT J AU DeMartini, EE Lau, BB AF DeMartini, EE Lau, BB TI Morphometric criteria for estimating sexual maturity in two snappers, Etelis carbunculus and Pristipomoides sieboldii SO FISHERY BULLETIN LA English DT Article ID SOLEA-SOLEA L; REPRODUCTIVE-CYCLE; DISCRIMINANT-ANALYSIS; LOGISTIC REGRESSION; OVARIAN DEVELOPMENT; FECUNDITY; FISHES; INDEX; MATURATION; GROWTH AB A gross measure of reproductive condition (ovary weight adjusted for body size and oocyte volume) is developed and evaluated as an alternative to commonly used gonad indices, for classifying the maturity status of individual ehu (Etelis carbunculus) and kalekale (Pristipomoides sieboldii), two species of eteline snappers (Lutjanidae) that contribute to the deep-slope hand-line fishery in Hawaii. Discriminant analysis and logistic regression, based on body length, ovary weight, and oocyte volume, were used to classify fish as either immature or mature. Discriminant analysis correctly classified the maturity of about 98% of both ehu and kalekale, with histological criteria as the standard for comparison. Logistic regression correctly classified maturity of 97% of the ehu and 100% of the kalekale. Misclassification errors increased by 3.75-5% (discriminant analysis) or 0-5% (logistic regression) if oocyte volume was excluded and only body length and ovary weight were used as predictors of maturity. For kalekale, estimates of lengths at which 50% are sexually mature (L-50) were identical (29.0 +/- 1.8 [SE] cm fork length, FL; r(2)-=0.92), when maturity was classified histologically or by logistic regression on body, ovary, and oocyte metrics. For ehu, L-50 estimates were similar (r(2)-approximate to 0.96) for maturity assignments based on histology(27.9 +/- 2.4 cm FL) and on logistic regression using gross metrics (27.8 +/- 2.3 cm FL). We conclude that gross morphometrics can provide adequate proxies for histological evidence when categorizing sexual maturity in asynchronous, multiple-spawning fishes like eteline lutjanids. The potential benefits of using gross metrics for assessing sexual maturity in other serial spawners are briefly 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 51 TC 21 Z9 25 U1 1 U2 3 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 1999 VL 97 IS 3 BP 449 EP 458 PG 10 WC Fisheries SC Fisheries GA 216GH UT WOS:000081432700004 ER PT J AU Friedland, KD Dutil, JD Sadusky, T AF Friedland, KD Dutil, JD Sadusky, T TI Growth patterns in postsmolts and the nature of the marine juvenile nursery for Atlantic salmon, Salmo salar SO FISHERY BULLETIN LA English DT Article ID SMOLT; SURVIVAL; ENVIRONMENT; POPULATIONS; MATURATION; SEA AB We examined scale samples from historical collections of postsmolts from the Gulf of St. Lawrence, Canada, with the aim of understanding the role of estuarine and coastal habitats as a juvenile nursery for Atlantic salmon. Circuli spacing patterns were extracted from the scales of 580 postsmolts collected in the Gulf during three seasons, 1982-84. Poststratification of the samples by collection date within year suggests that in some years postsmolts remain in the Gulf throughout the entire summer growth season, whereas in other years only slower growing fish remain in these areas. Growth patterns for Gulf of St. Lawrence postsmolts were compared with patterns for returns from three salmon stocks from the southern end of the range in North America. These data suggest that in some years postsmolt growth in the Gulf is as robust as that observed for both the one seawinter (1SW) and two seawinter (2SW) returns to southern rivers. Postsmolts are believed to use oceanic nursery areas generally; thus, comparable growth between the two stock groups suggests that the Gulf may serve as an important part of the postsmolt nursery range in some years. The concept of the postsmolt nursery as a continuum between neritic and oceanic areas is essential to evaluating ocean climate and productivity effects on salmonid recruitment. C1 Univ Massachusetts, NOAA, CMER Program, Amherst, MA 01003 USA. Minist Peches & Oceans, Inst Maurice Lamontagne, Mt Joli, PQ G5H 3Z4, Canada. NOAA, Natl Marine Fisheries Serv, Woods Hole, MA 02543 USA. RP Friedland, KD (reprint author), Univ Massachusetts, NOAA, CMER Program, Blaisdell House, Amherst, MA 01003 USA. NR 29 TC 17 Z9 18 U1 0 U2 1 PU NATL MARINE FISHERIES SERVICE SCIENTIFIC PUBL OFFICE PI SEATTLE PA 7600 SAND POINT WAY NE BIN C15700, SEATTLE, WA 98115 USA SN 0090-0656 J9 FISH B-NOAA JI Fish. Bull. PD JUL PY 1999 VL 97 IS 3 BP 472 EP 481 PG 10 WC Fisheries SC Fisheries GA 216GH UT WOS:000081432700006 ER PT J AU Perkins, PC Edwards, EF AF Perkins, PC Edwards, EF TI Capture rate as a function of school size in pantropical spotted dolphins, Stenella attenuata, in the eastern tropical Pacific Ocean SO FISHERY BULLETIN LA English DT Article AB The frequency with which dolphins from the northeastern offshore stock of the pantropical spotted dolphin, Stenella attenuata, experience chase and capture by tuna purse-seiners in the eastern topical Pacific Ocean was estimated by comparing dolphin school-size frequencies in sighting data from research vessel observer records, with those recorded ins vessel observers. The objective of the study was to provide a preliminary basis for estimating stock-wide effects of fishery-induced disturbance in these dolphins. Our analyses indicate two major characteristics for this stock: first, capture frequency appears to increase rapidly with increasing school size, and second, approximately half of the stock at any given time occurs in schools smaller than those apparently preferred by purse-seiners. This implies that if individual dolphins have a preference for associating with schools of a particular size, then individuals associating primarily with large schools would be subjected to chase and capture much more frequently than those associating with small schools. However, because the largest schools are relatively rare and account for a small percentage of individuals, the majority of dolphins in the stock would experience relatively few captures per year, although some would experience a high rate. It is not known whether dolphins do indeed exhibit such a preference, or if instead individuals associate with schools from a wide range of sizes at different times. Schools of 1000 or more dolphins are estimated to be set on approximately once a week each on average, but such schools are estimated to represent just under one tenth of the animals in the northeastern offshore stock. Schools set on most often by tuna purse-seiners, containing from about 250 to 500 dolphins, are estimated to be set on between two and eight times each per year and are estimated to include approximately one third of the stock. An estimated one half of the stock occurs in schools smaller than 250 animals; schools of this size are estimated to be set on less than twice per year each. C1 SW Fisheries Sci Ctr, La Jolla, CA 92038 USA. RP Perkins, PC (reprint author), SW Fisheries Sci Ctr, 8604 La Jolla Shores Dr, La Jolla, CA 92038 USA. NR 20 TC 9 Z9 9 U1 0 U2 1 PU NATL MARINE FISHERIES SERVICE SCIENTIFIC PUBL OFFICE PI SEATTLE PA 7600 SAND POINT WAY NE BIN C15700, SEATTLE, WA 98115 USA SN 0090-0656 J9 FISH B-NOAA JI Fish. Bull. PD JUL PY 1999 VL 97 IS 3 BP 542 EP 554 PG 13 WC Fisheries SC Fisheries GA 216GH UT WOS:000081432700011 ER PT J AU Sigler, MF AF Sigler, MF TI Estimation of sablefish, Anoplopoma fimbria, abundance off Alaska with an age-structured population model SO FISHERY BULLETIN LA English DT Article ID SAMPLING TRAWL; GENERAL-THEORY; CATCH; VARIABILITY AB Relative abundance of sablefish, Anoplopoma fimbria, in the waters off Alaska has been measured annually since 1979 with longline surveys. These extensive surveys provide precise measures of relative abundance. An age-structured model was fitted to the longline survey data to estimate absolute abundance. Estimates of recent exploitation rates for fully selected ages averaged 10%. Monte Carlo simulations of the age-structured model indicated that absolute abundance of Alaskan sablefish can be estimated reliably if age selectivity is asymptotic and not dome-shaped. Abundance estimates were reliable even when only length data and no age data were available. Dome-shaped selectivity gave biased and less precise estimates, probably owing to a parameter interaction between catchability and the shape of the selectivity function. C1 Alaska Fisheries Sci Ctr, Auke Bay Lab, Juneau, AK 99801 USA. RP Sigler, MF (reprint author), Alaska Fisheries Sci Ctr, Auke Bay Lab, 11305 Glacier Hwy, Juneau, AK 99801 USA. NR 27 TC 5 Z9 5 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 1999 VL 97 IS 3 BP 591 EP 603 PG 13 WC Fisheries SC Fisheries GA 216GH UT WOS:000081432700015 ER PT J AU Somerton, DA Otto, RS AF Somerton, DA Otto, RS TI Net efficiency of a survey trawl for snow crab, Chionoecetes opilio, and Tanner crab, C-bairdi SO FISHERY BULLETIN LA English DT Article ID CAPTURE EFFICIENCY; THEORETICAL-MODEL; GEAR; SIZE AB Snow crab (Chionoecetes opilio) and Tanner crab (C. bairdi) fisheries in the eastern Bering Sea are managed by using swept-area estimates of biomass based on an annual survey conducted with a 83-112 eastern bottom trawl. Estimates of net efficiency (i.e. the capture probability of crab that occur between the wing-tips of the trawl net) are needed to correct the biomass estimates for any size selectivity by the trawl. Data on net efficiency were obtained experimentally by attaching an auxiliary net beneath the trawl net to capture crab escaping under the trawl footrope. Net efficiency is then the quotient of the trawl catch divided by the combined catch of the trawl and auxiliary nets. Mathematical models of the relationship between net efficiency and carapace width were formulated and fitted to the experimental data. Net efficiency for both species first decreased with increasing carapace width until a minimum efficiency was reached near 50 mm carapace width. At larger sizes, efficiency in creased asymptotically with carapace width. Net efficiency for mature female Tanner crab was lower (0.47) than for males and immature females combined (0.72) at the same mean carapace width as mature females (66-107 mm). Net efficiency did not differ between morphologically mature and immature male Tanner crabs of the same carapace width. C1 NOAA, Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr, Seattle, WA 98125 USA. NOAA, Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr, Kodiak Lab, Kodiak, AK 99615 USA. RP Somerton, DA (reprint author), NOAA, Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr, 7600 Sand Point Way NE, Seattle, WA 98125 USA. NR 11 TC 24 Z9 24 U1 1 U2 1 PU NATL MARINE FISHERIES SERVICE SCIENTIFIC PUBL OFFICE PI SEATTLE PA 7600 SAND POINT WAY NE BIN C15700, SEATTLE, WA 98115 USA SN 0090-0656 J9 FISH B-NOAA JI Fish. Bull. PD JUL PY 1999 VL 97 IS 3 BP 617 EP 625 PG 9 WC Fisheries SC Fisheries GA 216GH UT WOS:000081432700017 ER PT J AU Woodbury, D AF Woodbury, D TI Reduction of growth in otoliths of widow and yellowtail rockfish (Sebastes entomelas and S-flavidus) during the 1983 El Nino SO FISHERY BULLETIN LA English DT Article ID PACIFIC-OCEAN; GENUS SEBASTES; NORTH-AMERICA; CALIFORNIA; WASHINGTON; MOVEMENTS; HABITS; OREGON; COAST; SIZE AB Growth of otoliths of adult widow rockfish, Sebastes entomelas, and yellowtail rockfish, S. flavidus, inhabiting the coastal waters off central and northern California was reduced in 1983. This reduction (12.6% and 20.5%, respectively) coincided with a strong El Nino event that dominated oceanographic conditions that year. Otolith growth from 1980 to 1987 was significantly correlated with ocean temperature, upwelling, and sea level anomaly. Specifically, in 1983, the highest ocean temperature, largest positive sea level anomaly, and lowest amount of coastal upwelling corresponded to the smallest mean otolith growth increment. C1 NOAA, Natl Marine Fisheries Serv, SW Fisheries Sci Ctr, Tiburon, CA 94920 USA. RP Woodbury, D (reprint author), NOAA, Natl Marine Fisheries Serv, SW Fisheries Sci Ctr, 3150 Paradise Dr, Tiburon, CA 94920 USA. EM David.Woodbury@noaa.gov NR 34 TC 27 Z9 28 U1 0 U2 5 PU NATL MARINE FISHERIES SERVICE SCIENTIFIC PUBL OFFICE PI SEATTLE PA 7600 SAND POINT WAY NE BIN C15700, SEATTLE, WA 98115 USA SN 0090-0656 EI 1937-4518 J9 FISH B-NOAA JI Fish. Bull. PD JUL PY 1999 VL 97 IS 3 BP 680 EP 689 PG 10 WC Fisheries SC Fisheries GA 216GH UT WOS:000081432700022 ER PT J AU Porter, SM Theilacker, GH AF Porter, SM Theilacker, GH TI The development of the digestive tract and eye in larval walleye pollock, Theragra chalcogramma SO FISHERY BULLETIN LA English DT Article ID EARLY LIFE-HISTORY; ENGRAULIS-MORDAX; LABORATORY CONDITIONS; NORTHERN ANCHOVY; STARVATION; GULF; SEA; TELEOSTS; BEHAVIOR; MACKEREL C1 NOAA, Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr, Seattle, WA 98115 USA. RP Porter, SM (reprint author), NOAA, Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr, 7600 Sand Point Way NE, Seattle, WA 98115 USA. NR 35 TC 22 Z9 22 U1 0 U2 1 PU NATL MARINE FISHERIES SERVICE SCIENTIFIC PUBL OFFICE PI SEATTLE PA 7600 SAND POINT WAY NE BIN C15700, SEATTLE, WA 98115 USA SN 0090-0656 J9 FISH B-NOAA JI Fish. Bull. PD JUL PY 1999 VL 97 IS 3 BP 722 EP 729 PG 8 WC Fisheries SC Fisheries GA 216GH UT WOS:000081432700027 ER PT J AU Davies, B Bromage, N Swanson, P AF Davies, B Bromage, N Swanson, P TI The brain-pituitary-gonadal axis of female rainbow trout Oncorhynchus mykiss: Effects of photoperiod manipulation SO GENERAL AND COMPARATIVE ENDOCRINOLOGY LA English DT Article DE trout; photoperiod; reproduction; gonadotropin-releasing hormone; gonadotropin ID GONADOTROPINS GTH-I; CHICKEN GNRH-II; DISTINCT SALMON GONADOTROPINS; REPRODUCTIVE-CYCLE; OVARIAN DEVELOPMENT; PLASMA GONADOTROPIN; SEASONAL-VARIATIONS; ATLANTIC SALMON; SERUM LEVELS; MASU SALMON AB (1)Two groups of post-spawned female rainbow trout were exposed to two different photoperiods, an ambient photoperiod (56 degrees N) and a combination of long and short photoperiods (a constant 18L:6D from February 1 until May 10, then a constant 6L:18D), which acted to advance maturation and spawning. The stimulatory long-short photoperiod advanced spawning by 3-4 months and correspondingly advanced peaks in serum levels of 17 beta-estradiol, testosterone, calcium (an index of vitellogenin), and GTH II. Earlier events in gonadal recrudescence appeared to be less affected by the photoperiod. The initiation of exogenous vitellogenesis coincided with high levels of bo th pituitary salmon gonadotropin-releasing hormone (sGnRH) content and serum follicle-stimulating hormone (FSH, GTH I) levels. High levels of serum FSH were associated with rapid gonadal growth in the fish exposed to the stimulatory long-short photoperiod. In contrast, the fish exposed to the ambient photoperiod showed gonadal steroid production, formation of vitellogenin, and secondary oocyte growth without any detectable increase in serum FSH levels. The possible roles and interactions of sGnRH, gonadotropins, and steroids with respect to normal and artificially stimulated ovarian maturation are discussed. (C) 1999 Academic Press. C1 NOAA, Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, Seattle, WA 98112 USA. Univ Stirling, Inst Aquaculture, Stirling FK9 4LA, Scotland. RP Davies, B (reprint author), NOAA, Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, 2725 Montlake Blvd E, Seattle, WA 98112 USA. NR 61 TC 57 Z9 59 U1 1 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 1999 VL 115 IS 1 BP 155 EP 166 DI 10.1006/gcen.1999.7301 PG 12 WC Endocrinology & Metabolism SC Endocrinology & Metabolism GA 213HQ UT WOS:000081267000016 PM 10375474 ER PT J AU Minnis, P Schumann, U Doelling, DR Gierens, KM Fahey, DW AF Minnis, P Schumann, U Doelling, DR Gierens, KM Fahey, DW TI Global distribution of contrail radiative forcing SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID AIRCRAFT EXHAUST; CIRRUS CLOUDS; EMISSIONS AB The global distribution of radiative forcing by persistent linear contrails has been estimated for 1992 and 2050 using global contrail cover computed for aircraft fuel consumption scenarios for the two periods, a detailed prescription of the radiative properties of the Earth's surface and the cloudy atmosphere, and flux computations with an established radiative transfer model. The computed global mean radiative forcing by line-shaped contrails is similar to 0.02 Wm(-2) in 1992 and similar to 0.1 Wm(-2) in 2050. At northern mid-latitudes, the zonal mean forcing is five times larger than the global mean. Diffuse contrails and indirect effects of aircraft emissions on natural cirrus are not included in this study. Thus, the results are considered a minimum estimate of contrail effects. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. DLR Oberfaffenhofen, Inst Phys Atmosphare, D-82230 Wessling, Germany. NASA, Langley Res Ctr, Analyt & Mat Inc, Hampton, VA 23666 USA. NOAA, Aeron Lab, Boulder, CO 80303 USA. RP Minnis, P (reprint author), NASA, Langley Res Ctr, MS 420, Hampton, VA 23681 USA. RI Fahey, David/G-4499-2013; Minnis, Patrick/G-1902-2010; OI Fahey, David/0000-0003-1720-0634; Minnis, Patrick/0000-0002-4733-6148; Schumann, Ulrich/0000-0001-5255-6869 NR 26 TC 86 Z9 86 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 JUL 1 PY 1999 VL 26 IS 13 BP 1853 EP 1856 DI 10.1029/1999GL900358 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 213TU UT WOS:000081290000018 ER PT J AU Gnanadesikan, A Toggweiler, JR AF Gnanadesikan, A Toggweiler, JR TI Constraints placed by silicon cycling on vertical exchange in general circulation models SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID WORLD OCEAN AB The flux of biogenic silica out of the oceanic mixed layer (the export flux) must balance the import of high-silicate deep waters associated with mass exchange between the surface and deep ocean. Recent regional estimates of the export flux limit it to 50-80 Tmol yr(-1). In order to reproduce such low export fluxes, coarse-resolution general circulation models must have low pycnocline diffusivity and a lateral exchange scheme which involves advection of tracers by unresolved mesoscale eddies. Failure to capture low rates of vertical exchange will result in climate models which overpredict the uptake of anthropogenic carbon dioxide and fail to capture the proper locations and rates of density transformation. C1 Princeton Univ, Atmospher & Ocean Sci Program, Princeton, NJ 08544 USA. NOAA, Geophys Fluid Dynam Lab, Princeton, NJ 08542 USA. RP Gnanadesikan, A (reprint author), Princeton Univ, Atmospher & Ocean Sci Program, POB CN710, Princeton, NJ 08544 USA. RI Gnanadesikan, Anand/A-2397-2008 OI Gnanadesikan, Anand/0000-0001-5784-1116 NR 20 TC 27 Z9 28 U1 1 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUL 1 PY 1999 VL 26 IS 13 BP 1865 EP 1868 DI 10.1029/1999GL900379 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 213TU UT WOS:000081290000021 ER PT J AU Dixon, KW Lanzante, JR AF Dixon, KW Lanzante, JR TI Global mean surface air temperature and North Atlantic overturning in a suite of coupled GCM climate change experiments SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID OCEAN-ATMOSPHERE MODEL; COLD START PROBLEM; TRANSIENT-RESPONSE; GREENHOUSE-GAS; CIRCULATION; CO2 AB The effects of model initial conditions and the starting time of transient radiative forcings on global mean surface air temperature (SAT) and the North Atlantic thermohaline circulation (THC) are studied in a set of coupled climate GCM experiments. Nine climate change scenario experiments, in which the effective levels of greenhouse gases and tropospheric sulfate aerosols vary in time, are initialized from various points in a long control model run. The time at which the transition from constant to transient radiative forcing takes place is varied in the scenario runs, occurring at points representing either year 1766, 1866 or 1916. The sensitivity of projected 21st century global mean SATs and the THC to the choice of radiative forcing transition point is small, and is similar in magnitude to the variability arising from variations in the coupled GCM's initial three-dimensional state. C1 NOAA, Geophys Fluid Dynam Lab, Princeton, NJ 08542 USA. RP Dixon, KW (reprint author), NOAA, Geophys Fluid Dynam Lab, POB 308, Princeton, NJ 08542 USA. RI Dixon, Keith/L-7120-2015 OI Dixon, Keith/0000-0003-3044-326X NR 16 TC 26 Z9 26 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUL 1 PY 1999 VL 26 IS 13 BP 1885 EP 1888 DI 10.1029/1999GL900382 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 213TU UT WOS:000081290000026 ER PT J AU Wanninkhof, R McGillis, WR AF Wanninkhof, R McGillis, WR TI A cubic relationship between air-sea CO2 exchange and wind speed SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID GAS-EXCHANGE; FLUX; OCEAN AB Using recent laboratory and field results we explore the possibility of a cubic relationship between gas exchange and instantaneous (or short-term) wind speed, and its impact on global air-sea fluxes. The theoretical foundation for such a dependency is based on retardation of gas transfer at low to intermediate winds by surfactants, which are ubiquitous in the world's oceans, and bubble-enhanced transfer at higher winds. The proposed cubic relationship shows a weaker dependence of gas transfer at low wind speed and a significantly stronger dependence at high wind speed than previous relationships. A long-term relationship derived from such a dependence, combined with the monthly CO2 climatology of Takahashi [1997], leads to an increase in the global annual oceanic CO2 uptake from 1.4 Gigaton C yr(-1) to 2.2 Gigaton C yr(-1). Although a cubic relationship fits within global bomb-C-14 oceanic uptake constraints, additional checks are warranted, particularly at high wind speeds where the enhancement is most pronounced. C1 NOAA, Atlantic Oceanog & Meteorol Lab, Miami, FL 33149 USA. Woods Hole Oceanog Inst, Dept Appl Ocean Phys & Engn, Woods Hole, MA 02543 USA. RP Wanninkhof, R (reprint author), NOAA, Atlantic Oceanog & Meteorol Lab, 4301 Rickenbacker Causeway, Miami, FL 33149 USA. RI Mason, Robert/A-6829-2011 NR 21 TC 407 Z9 429 U1 0 U2 39 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 1 PY 1999 VL 26 IS 13 BP 1889 EP 1892 DI 10.1029/1999GL900363 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 213TU UT WOS:000081290000027 ER PT J AU Hart, DR Mulholland, PJ Marzolf, ER DeAngelis, DL Hendricks, SP AF Hart, DR Mulholland, PJ Marzolf, ER DeAngelis, DL Hendricks, SP TI Relationships between hydraulic parameters in a small stream under varying flow and seasonal conditions SO HYDROLOGICAL PROCESSES LA English DT Article DE transient storage; hyporheic zone; solute transport; stream hydraulic parameters; longitudinal dispersion ID TRANSIENT STORAGE MODEL; SOLUTE TRANSPORT; SURFACE-WATER; RIFFLE STREAM; MASS-TRANSFER; NUTRIENT; EXCHANGE; RIVER; SIMULATION; ECOSYSTEMS AB Twenty conservative tracer injections were carried, out in the same reach of a small woodland stream in order to determine how variation in discharge and leaf accumulation affect stream hydraulic parameters. The injections were made at various discharge rates ranging from 2.6 to 40 l/s. Five of the injections were made during late autumn, when there were large accumulations of leaves in the stream. Estimates of hydraulic parameters were made by fitting a transient storage solute transport model to conservative tracer concentration profiles. Velocity increased almost linearly with increasing discharge, indicating a decline in the Darcy friction factor. Dispersion also increased with increasing discharge, especially for the lower flow injections. The relative size of the storage zone was small (similar to 0.1). There was no definable relationship between discharge and the relative storage zone size, but the rates of exchange between the storage zone and the main channel increased markedly with increasing discharge. The presence of large accumulations of leaves had a clear effect on the hydraulic characteristics of the stream, producing much higher friction factors, larger storage zone sizes and lower velocity than would have been predicted by discharge alone. Copyright (C) 1999 John Wiley & Sons, Ltd. C1 Tel Aviv Univ, Dept Zool, IL-69978 Ramat Aviv, Israel. RP Hart, DR (reprint author), NE Fisheries Sci Ctr, 166 Water St, Woods Hole, MA 02543 USA. RI Mulholland, Patrick/C-3142-2012 NR 33 TC 49 Z9 52 U1 0 U2 5 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX PO19 1UD, ENGLAND SN 0885-6087 J9 HYDROL PROCESS JI Hydrol. Process. PD JUL PY 1999 VL 13 IS 10 BP 1497 EP 1510 DI 10.1002/(SICI)1099-1085(199907)13:10<1497::AID-HYP825>3.0.CO;2-1 PG 14 WC Water Resources SC Water Resources GA 221YR UT WOS:000081755900006 ER PT J AU Mechels, S Takada, K Okamoto, K AF Mechels, S Takada, K Okamoto, K TI Optical low-coherence reflectometer for measuring WDM components SO IEEE PHOTONICS TECHNOLOGY LETTERS LA English DT Article DE integrated optics; optical interferometry; optical planar waveguide components; optical reflection; wavelength-division multiplexing AB We developed an optical low coherence reflectometer (OLCR) that is specialized for measuring wavelength dependent reflectances from wavelength division multiplexed components. The system is a complex: OLCR (uses fringes and Fourier transform spectroscopy to obtain phase information) and is superior to conventional (envelope detection) OLCR in that reflected phase information can be used to resolve the reflectance amplitudes within narrow spectral windows. The system also contains several improvements over previous complex OLCR configurations, including a copropagating reference signal for minimum fringe degradation and a polarization diversity detection scheme. We used the system to measure internal reflections from several arrayed-waveguide gratings. C1 NTT, Optoelect Labs, Tokai, Ibaraki 3191193, Japan. RP Mechels, S (reprint author), Natl Inst Stand & Technol, 325 Broadway, Boulder, CO 80303 USA. NR 5 TC 10 Z9 10 U1 0 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 1041-1135 J9 IEEE PHOTONIC TECH L JI IEEE Photonics Technol. Lett. PD JUL PY 1999 VL 11 IS 7 BP 857 EP 859 DI 10.1109/68.769731 PG 3 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA 207YP UT WOS:000080963600031 ER PT J AU Voas, J AF Voas, J TI Certification: Reducing the hidden costs of poor quality SO IEEE SOFTWARE LA English DT Editorial Material AB Software development is increasingly an "acquire and glue" process. How do you know:when you: can trust a COTS component to do what you expect it to in your system?. Software certification is one viable answer. If our industry doesn't act soon to police itself, governments might step in to fill that void. C1 Reliable Software Technol, Sterling, VA 22170 USA. Natl Inst Stand & Technol, Gaithersburg, MD USA. USA, Washington, DC USA. RP Voas, J (reprint author), Reliable Software Technol, Sterling, VA 22170 USA. NR 2 TC 6 Z9 6 U1 1 U2 2 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1314 USA SN 0740-7459 J9 IEEE SOFTWARE JI IEEE Softw. PD JUL-AUG PY 1999 VL 16 IS 4 BP 22 EP 25 DI 10.1109/MS.1999.776944 PG 4 WC Computer Science, Software Engineering SC Computer Science GA 215ML UT WOS:000081385400012 ER PT J AU Wakid, SA Kuhn, DR Wallace, DR AF Wakid, SA Kuhn, DR Wallace, DR TI Toward credible IT testing and certification SO IEEE SOFTWARE LA English DT Article AB Accessible, rigorous measurement and test methods are key to creating quality software and increasing IT market competition. The authors describe here how their work at NIST contributes to these goals. C1 Natl Inst Stand & Technol, Informat Technol Lab, Gaithersburg, MD 20899 USA. NIST, Software Qual Grp, Gaithersburg, MD 20899 USA. RP Wakid, SA (reprint author), Natl Inst Stand & Technol, Informat Technol Lab, Bldg 820,Room 562, Gaithersburg, MD 20899 USA. NR 6 TC 2 Z9 2 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 0740-7459 J9 IEEE SOFTWARE JI IEEE Softw. PD JUL-AUG PY 1999 VL 16 IS 4 BP 39 EP 47 DI 10.1109/52.776947 PG 9 WC Computer Science, Software Engineering SC Computer Science GA 215ML UT WOS:000081385400015 ER PT J AU Voas, J AF Voas, J TI Certifying software for high-assurance environments SO IEEE SOFTWARE LA English DT Article AB Not all software systems are created equal or alike, particularly with the increase in COTS and reuseable components. Jeffrey Voas proposes a strategy for certifying software in specific operational environments. C1 Reliable Software Technol, Dulles, VA 20166 USA. Natl Inst Stand & Technol, Gaithersburg, MD USA. USA, Washington, DC USA. RP Voas, J (reprint author), Reliable Software Technol, Suite 400,21351 Ridgetop Circle, Dulles, VA 20166 USA. NR 12 TC 20 Z9 20 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 0740-7459 J9 IEEE SOFTWARE JI IEEE Softw. PD JUL-AUG PY 1999 VL 16 IS 4 BP 48 EP 54 DI 10.1109/52.776948 PG 7 WC Computer Science, Software Engineering SC Computer Science GA 215ML UT WOS:000081385400016 ER PT J AU Zhu, HB Hefner, AR Lai, JS AF Zhu, HB Hefner, AR Lai, JS TI Characterization of power electronics system interconnect parasitics using time domain reflectometry SO IEEE TRANSACTIONS ON POWER ELECTRONICS LA English DT Article DE device packaging; IGBT model; interconnect parasitics; power inverter; time domain reflectometry ID CIRCUIT AB The significance of interconnect parasitics of power electronics systems is their effects on converters' electromagnetic interference (EMI)-related performances, such as voltage/current spikes, dv/dt,di/dt, conducted/radiated EMI noise, etc. In this paper, a time domain reflectometry (TDR) measurement-based modeling technique is described for characterizing interconnect parasitics in switching power converters. Experiments are conducted on power components of a prototype high-power inverter, including insulated gate bipolar transistor (IGBT) modules, busbar, and bulk capacitors. It is shown that the interconnect inductance of the IGBT module can be extracted completely using TDR, It is also shown that the busbar equivalent circuit can he modeled as transmission line segments or L-C filter sections, and the bulk capacitor contains a significant equivalent series interconnect inductance. C1 Virginia Polytech Inst & State Univ, Bradley Dept Elect Engn, Ctr Power Elect Syst, Blacksburg, VA 24061 USA. Natl Inst Stand & Technol, Semicond Elect Div, Gaithersburg, MD 20899 USA. RP Virginia Polytech Inst & State Univ, Bradley Dept Elect Engn, Ctr Power Elect Syst, Blacksburg, VA 24061 USA. OI Lai, Jihsheng/0000-0003-2315-8460 NR 19 TC 39 Z9 45 U1 0 U2 4 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 0885-8993 EI 1941-0107 J9 IEEE T POWER ELECTR JI IEEE Trans. Power Electron. PD JUL PY 1999 VL 14 IS 4 BP 622 EP 628 DI 10.1109/63.774198 PG 7 WC Engineering, Electrical & Electronic SC Engineering GA 214HC UT WOS:000081321700004 ER PT J AU Levine, J AF Levine, J TI Time synchronization over the internet using an. Adaptive frequency-locked loop SO IEEE TRANSACTIONS ON ULTRASONICS FERROELECTRICS AND FREQUENCY CONTROL LA English DT Article ID PROBABILISTIC CLOCK SYNCHRONIZATION; COMPUTER AB This paper describes the operation of an algorithm for synchronizing the time of computers using messages transmitted,ver packet-switched networks such as the Internet. The algorithm configures itself to realize any specified performance level at minimum cost (measured in computer cycles or network bandwidth). If the highest possible accuracy is requested, the performance will be limited by the larger of the instability of the local clock oscillator or the noise in the measurement process between the client and the server; I have obtained uncertainties of about 8 ms RMS using standard workstations and average network connections. Lower accuracy can be realized at substantially lower cost because the cost varies approximately as the inverse of the accuracy squared over a wide range of these parameters. The algorithm makes better use of scarce network bandwidth than previous methods. This improvement is realized by using a pure frequency-locked loop (rather than mixed frequency/phase locking algorithms currently proposed for the NTP) with unequal spacing between calibration cycles. The result is a cleaner separation between network noise and clock noise, which is especially important when the highest possible accuracy is desired. In addition, the algorithm is an improvement over the pure-FLL "Interlock" algorithm that I described previously because it is self configuring. In addition to supporting an explicit trade-off between cost and accuracy, the algorithm provides better performance than previous methods because it is better able to adapt itself to fluctuations in the asymmetry of the network delay. This robustness can be realized without the preliminary tuning that was necessary to realize optimum performance using previous methods. C1 Natl Inst Stand & Technol, JILA, Boulder, CO 80303 USA. Natl Inst Stand & Technol, Time & Frequency Div, Boulder, CO 80303 USA. Univ Colorado, Boulder, CO 80303 USA. RP Levine, J (reprint author), Natl Inst Stand & Technol, JILA, 325 Broadway, Boulder, CO 80303 USA. NR 6 TC 18 Z9 18 U1 3 U2 3 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 JUL PY 1999 VL 46 IS 4 BP 888 EP 896 DI 10.1109/58.775655 PG 9 WC Acoustics; Engineering, Electrical & Electronic SC Acoustics; Engineering GA 216XD UT WOS:000081469000016 PM 18238493 ER PT J AU Hartnett, JG Tobar, ME Mann, AG Ivanov, EN Krupka, J Geyer, R AF Hartnett, JG Tobar, ME Mann, AG Ivanov, EN Krupka, J Geyer, R TI Frequency-temperature compensation in Ti3+ and Ti4+ doped sapphire whispering gallery mode resonators SO IEEE TRANSACTIONS ON ULTRASONICS FERROELECTRICS AND FREQUENCY CONTROL LA English DT Article ID DIELECTRIC RESONATORS AB A new method of compensating the frequency-temperature dependence of high-Q monolithic sapphire dielectric resonators near liquid nitrogen temperature is presented. This is achieved by doping monocrystalline sapphire with Ti3+ ions. This technique offers significant advantages over other methods. C1 Univ Western Australia, Dept Phys, Nedlands, WA 6907, Australia. Warsaw Univ Technol, Dept Elect, Inst Microelect & Optoelect, Warsaw, Poland. Natl Inst Stand & Technol, Boulder, CO 80303 USA. RP Hartnett, JG (reprint author), Univ Western Australia, Dept Phys, Nedlands, WA 6907, Australia. RI Hartnett, John/F-7037-2010; Tobar, Michael/C-9763-2009 OI Tobar, Michael/0000-0002-3139-1994 NR 16 TC 36 Z9 36 U1 1 U2 6 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 JUL PY 1999 VL 46 IS 4 BP 993 EP 1000 DI 10.1109/58.775666 PG 8 WC Acoustics; Engineering, Electrical & Electronic SC Acoustics; Engineering GA 216XD UT WOS:000081469000027 PM 18238504 ER PT J AU Larson, KM Levine, J AF Larson, KM Levine, J TI Carrier-phase time transfer SO IEEE TRANSACTIONS ON ULTRASONICS FERROELECTRICS AND FREQUENCY CONTROL LA English DT Article ID GLOBAL POSITIONING SYSTEM; GPS; INTERFEROMETRY; GRADIENTS; PRECISION; ACCURACY AB We have conducted several time-transfer experiments using the phase of the GPS carrier rather than the code, as is done in current GPS-based time-transfer systems. Atomic clocks were connected to geodetic GPS receivers; we then used the GPS carrier-phase observations to estimate relative clock behavior at 6-minute intervals. GPS carrier-phase time transfer is more than an order of magnitude more precise than GPS common view time transfer and agrees, within the experimental uncertainty, with two-way satellite time-transfer measurements for a 2400-km baseline. GPS carrier-phase time transfer has a stability of 100 ps, which translates into a frequency uncertainty of about two parts in 10(15) for an average time of 1 d. C1 Univ Colorado, JILA, Boulder, CO 80309 USA. Univ Colorado, Dept Aerosp Engn Sci, Boulder, CO 80309 USA. Natl Inst Stand & Technol, JILA, Boulder, CO 80309 USA. Natl Inst Stand & Technol, Time & Frequency Div, Boulder, CO 80309 USA. RP Larson, KM (reprint author), Univ Colorado, JILA, Boulder, CO 80309 USA. NR 30 TC 35 Z9 36 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 0885-3010 J9 IEEE T ULTRASON FERR JI IEEE Trans. Ultrason. Ferroelectr. Freq. Control PD JUL PY 1999 VL 46 IS 4 BP 1001 EP 1012 DI 10.1109/58.775667 PG 12 WC Acoustics; Engineering, Electrical & Electronic SC Acoustics; Engineering GA 216XD UT WOS:000081469000028 PM 18238505 ER PT J AU Lu, YN Nerurkar, VR Aguirre, AA Work, TM Balazs, GH Yanagihara, R AF Lu, YN Nerurkar, VR Aguirre, AA Work, TM Balazs, GH Yanagihara, R TI Establishment and characterization of 13 cell lines from a green turtle (Chelonia mydas) with fibropapillomas SO IN VITRO CELLULAR & DEVELOPMENTAL BIOLOGY-ANIMAL LA English DT Article DE green turtle fibropapilloma; primary culture; cell line; tumor; turtle virus ID HAWAIIAN AB Thirteen cell lines were established and characterized from brain, kidney, lung, spleen, heart, liver. gall bladder urinary bladder, pancreas, testis, skin, and periorbital and tumor tissues of an immature male green turtle (Chelonia mydas) with fibropapillomas. Cell lines were optimally maintained at 30 degrees C in RPMI 1640 medium supplemented with 10% fetal bovine serum. Propagation of the turtle cell lines was serum dependent, and plating efficiencies ranged from 13 to 37%. The cell lines, which have been subcultivated more than 20 times, had a doubling time of approximately 30 to 36 h. When tested for their sensitivity to several fish viruses, most of the cell lines were susceptible to a rhabdovirus, spring viremia carp virus. but refractory; to channel catfish virus (a herpesvirus), infectious pancreatic necrosis virus (a birnavirus), and two other fish rhabdoviruses, infectious hematopoietic necrosis virus and viral hemorrhagic septicemia virus. During in vitro subcultivation: tumor-like cell aggregates appeared in cell lines derived from lungs, testis, and periorbital and tumor tissues, and small, naked intranuclear virus particles were detected by thin-section electron microscopy. These cell lines are currently being used in attempts to isolate the putative etiologic virus of green turtle fibropapilloma. C1 Univ Hawaii, Pacific Biomed Res Ctr, Retrovirol Res Lab, Leahi Hosp, Honolulu, HI 96816 USA. Natl Wildlife Hlth Ctr, Inst Marine & Atmospher Res, Honolulu, HI USA. Natl Marine Fisheries Serv, Honolulu, HI USA. RP Lu, YN (reprint author), Univ Hawaii, Pacific Biomed Res Ctr, Retrovirol Res Lab, Leahi Hosp, 3675 Kilauea Ave, Honolulu, HI 96816 USA. RI Work, Thierry/F-1550-2015 OI Work, Thierry/0000-0002-4426-9090 FU NCRR NIH HHS [G12RR/AI-03061] NR 27 TC 34 Z9 34 U1 1 U2 6 PU SOC IN VITRO BIOLOGY PI LARGO PA 9315 LARGO DR WEST, STE 25, LARGO, MD 20774 USA SN 1071-2690 J9 IN VITRO CELL DEV-AN JI In Vitro Cell. Dev. Biol.-Anim. PD JUL-AUG PY 1999 VL 35 IS 7 BP 389 EP 393 PG 5 WC Cell Biology; Developmental Biology SC Cell Biology; Developmental Biology GA 224QG UT WOS:000081909300006 PM 10462202 ER PT J AU Albus, JS AF Albus, JS TI The engineering of mind SO INFORMATION SCIENCES LA English DT Article AB While the mind remains a mysterious and inaccessible phenomenon, many of the components of mind, such as perception, behavior generation, knowledge representation, value judgment, reason, intention, emotion, memory, imagination, recognition, learning, attention, and intelligence are becoming well defined and amenable to analysis. Progress is rapid in the cognitive and neurosciences as well as in artificial intelligence, control theory, and many other fields related to the engineering of mind. A reference model architecture for intelligent systems is suggested to tie together concepts from all these separate fields into a unified framework that includes both biological and machine embodiments of the components of mind. It is argued that such a reference model architecture will facilitate the development of scientific models of mind. Published by Elsevier Science B.V. All rights reserved. C1 Natl Inst Stand & Technol, Intelligent Syst Div, Gaithersburg, MD 20895 USA. RP Albus, JS (reprint author), Natl Inst Stand & Technol, Intelligent Syst Div, Gaithersburg, MD 20895 USA. NR 10 TC 16 Z9 16 U1 0 U2 1 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 USA SN 0020-0255 J9 INFORM SCIENCES JI Inf. Sci. PD JUL PY 1999 VL 117 IS 1-2 BP 1 EP 18 DI 10.1016/S0020-0255(98)10102-0 PG 18 WC Computer Science, Information Systems SC Computer Science GA 216YH UT WOS:000081471700001 ER PT J AU Wiedenbeck, S Scholtz, J AF Wiedenbeck, S Scholtz, J TI Introduction to the special issue "Best of Empirical Studies of Programmers 7" SO INTERNATIONAL JOURNAL OF HUMAN-COMPUTER STUDIES LA English DT Editorial Material ID COMPUTER-PROGRAMS; PSYCHOLOGICAL EVALUATION; COMPREHENSION C1 Dalhousie Univ, Fac Comp Sci, Halifax, NS B3J 2X4, Canada. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Wiedenbeck, S (reprint author), Dalhousie Univ, Fac Comp Sci, Halifax, NS B3J 2X4, Canada. NR 14 TC 1 Z9 1 U1 0 U2 0 PU ACADEMIC PRESS LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 1071-5819 J9 INT J HUM-COMPUT ST JI Int. J. Hum.-Comput. Stud. PD JUL PY 1999 VL 51 IS 1 BP 3 EP 5 DI 10.1006/ijhc.1999.0266 PG 3 WC Computer Science, Cybernetics; Ergonomics; Psychology, Multidisciplinary SC Computer Science; Engineering; Psychology GA 218BF UT WOS:000081532900001 ER PT J AU McClure, JL Boboridis, K Cezairliyan, A AF McClure, JL Boboridis, K Cezairliyan, A TI Radiance temperatures (in the wavelength range 521 to 1500 nm) of rhenium and iridium at their melting points by a pulse-heating technique SO INTERNATIONAL JOURNAL OF THERMOPHYSICS LA English DT Article; Proceedings Paper CT 5th International Workshop on Subsecond Thermophysics CY JUN 16-19, 1998 CL AIX-EN PROVENCE, FRANCE DE emissivity (normal spectral); high-speed pyrometry; high-temperature fixed points; iridium; melting; pyrometry; radiance; temperature; rhenium ID NIOBIUM AB The melting-point radiance temperatures (at seven wavelengths in the range 521 to 1500 nm) of rhenium and iridium were measured by a pulse-heating technique. The method is based on rapid resistive self-heating of the specimen from room temperature to its melting point in less than is and on simultaneously measuring the specimen radiance temperature every 0.5 ms with two high-speed pyrometers. Melting was manifested by a plateau in the radiance temperature-versus-time function for each wavelength. The melting-point radiance temperatures for a given specimen were determined by averaging the measured temperatures along the plateau at each wavelength. The melting-point radiance temperatures for each metal were determined by averaging results for several specimens at each wavelength. The results are as follows. C1 Natl Inst Stand & Technol, Div Met, Gaithersburg, MD 20899 USA. RP Boboridis, K (reprint author), Natl Inst Stand & Technol, Div Met, 100 Bur Dr,Mail Stop 8557, Gaithersburg, MD 20899 USA. NR 17 TC 5 Z9 5 U1 0 U2 3 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0195-928X J9 INT J THERMOPHYS JI Int. J. Thermophys. PD JUL PY 1999 VL 20 IS 4 BP 1137 EP 1148 DI 10.1023/A:1022611121888 PG 12 WC Thermodynamics; Chemistry, Physical; Mechanics; Physics, Applied SC Thermodynamics; Chemistry; Mechanics; Physics GA 248BL UT WOS:000083255400014 ER PT J AU McClure, JL Cezairliyan, A Kaschnitz, E AF McClure, JL Cezairliyan, A Kaschnitz, E TI Radiance temperatures (in the wavelength range 527 to 1500 nm) of palladium and platinum at their melting points by a pulse-heating technique SO INTERNATIONAL JOURNAL OF THERMOPHYSICS LA English DT Article; Proceedings Paper CT 5th International Workshop on Subsecond Thermophysics CY JUN 16-19, 1998 CL AIX-EN PROVENCE, FRANCE DE emissivity (normal spectral); high-speed pyrometry; high temperature fixed points; melting; palladium; platinum; pyrometry; radiance temperature ID NIOBIUM; METALS AB The radiance temperatures (at seven wavelengths in the range 527 to 1500 nm) of palladium and platinum at their respective melting points were measured by a pulse-heating technique. The method. based on rapid resistive self-heating of a specimen from room temperature to its melting point in less than 1 s, used two high-speed pyrometers to measure specimen radiance temperatures every 9.5 ms during the heating and melting period. Melting was manifested by a plateau in the radiance temperature-versus-time function for each wavelength. The melting-point radiance temperatures for a given specimen were determined by averaging the measured temperatures along the plateau at each wavelength. The melting-point radiance temperatures for each metal as determined by averaging the results fbr several specimens at each wavelength are as follows. C1 NIST, Div Met, Gaithersburg, MD 20899 USA. Osterreich Giesserei Inst, A-8700 Leoben, Austria. RP McClure, JL (reprint author), NIST, Div Met, Gaithersburg, MD 20899 USA. NR 19 TC 6 Z9 6 U1 0 U2 1 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 1999 VL 20 IS 4 BP 1149 EP 1161 DI 10.1023/A:1022663105959 PG 13 WC Thermodynamics; Chemistry, Physical; Mechanics; Physics, Applied SC Thermodynamics; Chemistry; Mechanics; Physics GA 248BL UT WOS:000083255400015 ER PT J AU Baldocchi, DD Fuentes, JD Bowling, DR Turnipseed, AA Monson, RK AF Baldocchi, DD Fuentes, JD Bowling, DR Turnipseed, AA Monson, RK TI Scaling isoprene fluxes from leaves to canopies: Test cases over a boreal aspen and a mixed species temperate forest SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID WATER-VAPOR EXCHANGE; RELAXED EDDY ACCUMULATION; EMISSION RATE VARIABILITY; CARBON-DIOXIDE; DECIDUOUS FOREST; STOMATAL CONDUCTANCE; BOUNDARY-LAYER; SURFACE-LAYER; MODEL; PHOTOSYNTHESIS AB The rate at which isoprene is emitted by a forest depends on an array of environmental variables, the forest's biomass, and its species composition. At present it is unclear whether errors in canopy-scale and process-level isoprene emission models are due to inadequacies in leaf-to-canopy integration theory or the imperfect assessment of the isoprene-emitting biomass in the flux footprint. To address this issue, an isoprene emission model (CANVEG) was tested over a uniform aspen stand and a mixed-species, broad-leaved forest. The isoprene emission model consists of coupled micrometeorological and physiological modules. The micrometeorological module computes leaf and soil energy exchange, turbulent diffusion, scalar concentration profiles, and radiative transfer through the canopy. Environmental variables that are computed by the micrometeorological module, in turn, drive physiological modules that calculate leaf photosynthesis, stomatal conductance, transpiration and leaf, bole and soil/root respiration, and rates of isoprene emission. The isoprene emission model accurately predicted the diurnal variation of isoprene emission rates over the boreal aspen stand, as compared with micrometeorological flux measurements. The model's ability to simulate isoprene emission rates over the mixed temperate forest, on the other hand, depended strongly upon the amount of isoprene-emitting biomass, which, in a mixed-species forest, is a function of the wind direction and the horizontal dimensions of the flux footprint. When information on the spatial distribution of biomass and the flux footprint probability distribution function were included, the CANVEG model produced values of isoprene emission that compared well with micrometeorological measurements. The authors conclude that a mass and energy exchange model, which couples flows of carbon, water, and nutrients, can be a reliable tool for integrating leaf-scale, isoprene emission algorithms to the canopy dimension over dissimilar vegetation types as long as the vegetation is characterized appropriately. C1 NOAA, Atmospher Turbulence & Diffus Div, Oak Ridge, TN 37831 USA. Univ Virginia, Dept Environm Sci, Charlottesville, VA 22903 USA. Univ Colorado, Dept Environm Populat & Organism Biol, Boulder, CO 80309 USA. RP Baldocchi, DD (reprint author), NOAA, Atmospher Turbulence & Diffus Div, 456 S Illinois Ave, Oak Ridge, TN 37831 USA. RI Baldocchi, Dennis/A-1625-2009 OI Baldocchi, Dennis/0000-0003-3496-4919 NR 53 TC 38 Z9 38 U1 0 U2 13 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 1999 VL 38 IS 7 BP 885 EP 898 DI 10.1175/1520-0450(1999)038<0885:SIFFLT>2.0.CO;2 PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 219LE UT WOS:000081608100005 ER PT J AU Ruskell, TG Lohndorf, M Moreland, J AF Ruskell, TG Lohndorf, M Moreland, J TI Field mapping with the magnetic resonance force microscope SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID MECHANICAL DETECTION; CANTILEVERS; SILICON; DESIGN AB We have developed magnetic resonance force microscopy for quantitative measurements of magnetic fields. A microscopic particle attached near the end of a microcantilever serves as the field sensing probe. We have demonstrated two-dimensional field mapping with a lateral resolution of 3.2 mu m and a field resolution of 0.19 mT (1.9 G). The instrument holds considerable promise for field mapping with spatial resolution better than 0.1 mu m at room temperature. Applications include field mapping of magnetic recording heads. (C) 1999 American Institute of Physics. [S0021-8979(99)00513-7]. C1 Natl Inst Stand & Technol, Boulder, CO 80303 USA. RP Ruskell, TG (reprint author), Natl Inst Stand & Technol, 325 Broadway, Boulder, CO 80303 USA. NR 25 TC 4 Z9 4 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD JUL 1 PY 1999 VL 86 IS 1 BP 664 EP 670 DI 10.1063/1.370781 PG 7 WC Physics, Applied SC Physics GA 206BN UT WOS:000080856300087 ER PT J AU Westwater, ER Han, Y Irisov, VG Leuskiy, V Kadygrov, EN Viazankin, SA AF Westwater, ER Han, Y Irisov, VG Leuskiy, V Kadygrov, EN Viazankin, SA TI Remote sensing of boundary layer temperature profiles by a scanning 5-mm microwave radiometer and RASS: Comparison experiments SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article ID DESIGN; AIR AB Two techniques for deriving low-altitude temperature profiles were evaluated in an experiment conducted from November 1996 to January 1997 at the Boulder Atmospheric Observatory (BAO). The first used a scanning, single wavelength, 5-mm (60 GHz) microwave radiometer to measure vertical temperature profiles. Two radiometers were operated simultaneously; one used a discrete scan, the other scanned continuously. The second technique was a Radio Acoustic Sounding System (RASS) that operated at 915 MHz. Typically, radiometric profiles were produced every 15 min; those from RASS were 5-min segments taken every hour. Ground truth for the experiment was available from in situ measurements at the BAG. The BAO has an instrumented 300-m tower with 5-min measurements of temperature and relative humidity available at the surface and at altitudes of 10, 50, 100, 200, and 300 m. The tower measurements were occasionally supplemented with radiosonde releases and with hand-held meteorological measurements taken on the tower elevator. The differences between the radiometers and the tower sensors were about 1 degrees C rms. The accuracy using an in situ temperature measurement at the radiometer height as a predictor was also evaluated; at the 200- and 300-m levels, only about 4 degrees C rms accuracies resulted. During the experiment, the RASS occasionally experienced radio frequency interference; to eliminate these effects, a quality-control algorithm for the RASS system was developed and evaluated. In addition, an experiment was herd in September 1996 at the Department of Energy's Atmospheric Radiation Program Southern Great Plains site in north central Oklahoma. For this experiment, evaluations of a scanning 5-mm radiometer relative to 3-hourly radiosondes are presented. Quality control on the radiosondes was provided by comparisons with independent in situ surface and 60-m tower observations. The agreement between the radiometric profiles and the quality-controlled radiosondes was better than 1 degrees C up to 800 m. Plans for future deployments of these instruments are discussed. In addition to the in situ comparisons, theoretical analyses of the scanning radiometer systems were also conducted. The effects of angular resolution of the current system, noise level, prediction from in situ measurements, and vertical resolution were examined. C1 NOAA, ETL, MS R E ETI, Boulder, CO 80303 USA. Univ Colorado, NOAA, Environm Technol Lab, Cooperat Inst Res Environm Sci, Boulder, CO USA. Cent Aerol Observ, Microwave Remote Sensing Lab, Moscow, Russia. RP Westwater, ER (reprint author), NOAA, ETL, MS R E ETI, 325 Broadway, Boulder, CO 80303 USA. RI Han, Yong/F-5590-2010 OI Han, Yong/0000-0002-0183-7270 NR 20 TC 38 Z9 47 U1 1 U2 8 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 1999 VL 16 IS 7 BP 805 EP 818 DI 10.1175/1520-0426(1999)016<0805:RSOBLT>2.0.CO;2 PG 14 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA 217PG UT WOS:000081507700001 ER PT J AU Clothiaux, EE Moran, KP Martner, BE Ackerman, TP Mace, GG Uttal, T Mather, JH Widener, KB Miller, MA Rodriguez, DJ AF Clothiaux, EE Moran, KP Martner, BE Ackerman, TP Mace, GG Uttal, T Mather, JH Widener, KB Miller, MA Rodriguez, DJ TI The atmospheric radiation measurement program cloud radars: Operational modes SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article ID SIZE DISTRIBUTIONS; COMPLEMENTARY CODE AB During the past decade, the U.S. Department of Energy (DOE), through the Atmospheric Radiation Measurement (ARM) Program, has supported the development of several millimeter-wavelength radars for the study of clouds. This effort has culminated in the development and construction of a 35-GHz radar system by the Environmental Technology Laboratory (ETL) of the National Oceanic and Atmospheric Administration (NOAA). Radar systems based on the NOAA ETL design are now operating at the DOE ARM Southern Great Plains central facility in central Oklahoma and the DOE ARM North Slope of Alaska site near Barrow, Alaska. Operational systems are expected to come online within the next year at the DOE ARM tropical western Pacific sites located at Manus, Papua New Guinea, and Nauru. In order for these radars to detect the full range of atmospheric hydrometeors, specific modes of operation must be implemented on them that are tuned to accurately detect the reflectivities of specific types of hydrometeors. The set of four operational modes that are currently in use on these radars are presented and discussed. The characteristics of the data produced by these modes of operation are also presented in order to illustrate the nature of the cloud products that are, and will be, derived from them on a continuous basis. C1 Penn State Univ, Dept Meteorol, University Pk, PA 16802 USA. NOAA, Environm Technol Lab, Boulder, CO USA. Univ Utah, Dept Meteorol, Salt Lake City, UT 84112 USA. Batelle, Pacific NW Natl Lab, Richland, WA USA. Brookhaven Natl Lab, Dept Appl Sci, Upton, NY 11973 USA. Univ Calif Lawrence Livermore Natl Lab, Div Atmospher Sci, Livermore, CA USA. RP Clothiaux, EE (reprint author), Penn State Univ, Dept Meteorol, 503 Walker Bldg, University Pk, PA 16802 USA. NR 14 TC 63 Z9 65 U1 1 U2 7 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0739-0572 J9 J ATMOS OCEAN TECH JI J. Atmos. Ocean. Technol. PD JUL PY 1999 VL 16 IS 7 BP 819 EP 827 DI 10.1175/1520-0426(1999)016<0819:TARMPC>2.0.CO;2 PG 9 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA 217PG UT WOS:000081507700002 ER PT J AU Sanders, RW Solomon, S Kreher, K Johnston, PV AF Sanders, RW Solomon, S Kreher, K Johnston, PV TI An intercomparison of NO2 and OClO measurements at arrival heights, Antarctica during Austral spring 1996 SO JOURNAL OF ATMOSPHERIC CHEMISTRY LA English DT Article DE stratospheric trace gases; Antarctica; NO2; OClO ID ABSORPTION CROSS-SECTIONS; STRATOSPHERIC NO2; MCMURDO-STATION; TEMPERATURE-DEPENDENCE; VISIBLE SPECTROSCOPY; NEAR-ULTRAVIOLET; OZONE; CHLORINE; SPECTRUM; O-3 AB For several years NO2 and OClO, two species important to understanding ozone destruction in the Antarctic stratosphere, have been measured at Arrival Heights, Antarctica by two groups: New Zealand's National Institute of Water and Atmospheric Research (NIWA) and the NOAA Aeronomy Laboratory in Boulder, Colorado. Using data independently collected by these two groups during the Austral spring of 1996, it is shown that the two data sets are in extremely close agreement. Besides offering validation of the instrumentation and analysis techniques of both groups, this result provides confidence in the more complete history of these species gained by combining the two data sets. C1 NOAA, ERL, Aeron Lab, Boulder, CO 80303 USA. Natl Inst Water & Atmospher Res, Lauder, Central Otago, New Zealand. RP Sanders, RW (reprint author), NOAA, ERL, Aeron Lab, Boulder, CO 80303 USA. NR 27 TC 12 Z9 14 U1 2 U2 3 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0167-7764 J9 J ATMOS CHEM JI J. Atmos. Chem. PD JUL PY 1999 VL 33 IS 3 BP 283 EP 298 DI 10.1023/A:1006185027584 PG 16 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA 200YA UT WOS:000080566800004 ER PT J AU Heller, SR AF Heller, SR TI QuickBooks 99 SO JOURNAL OF CHEMICAL INFORMATION AND COMPUTER SCIENCES LA English DT Software Review C1 Natl Inst Stand & Technol, SRD, Gaithersburg, MD 20899 USA. RP Heller, SR (reprint author), Natl Inst Stand & Technol, SRD, Gaithersburg, MD 20899 USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0095-2338 J9 J CHEM INF COMP SCI JI J. Chem. Inf. Comput. Sci. PD JUL-AUG PY 1999 VL 39 IS 4 BP 765 EP 765 DI 10.1021/ci990383o PG 1 WC Chemistry, Multidisciplinary; Computer Science, Information Systems; Computer Science, Interdisciplinary Applications SC Chemistry; Computer Science GA 221MU UT WOS:000081731500021 ER PT J AU Liebmann, B Kiladis, GN Marengo, JA Ambrizzi, T Glick, JD AF Liebmann, B Kiladis, GN Marengo, JA Ambrizzi, T Glick, JD TI Submonthly convective variability over South America and the South Atlantic convergence zone SO JOURNAL OF CLIMATE LA English DT Article ID ROSSBY-WAVE PROPAGATION; SCALE COMMON FEATURES; BAIU FRONTAL ZONE; TROPICAL ATMOSPHERE; SUMMER CIRCULATION; NORTHERN WINTER; TIME SCALES; OSCILLATION; HEMISPHERE; MODEL AB Relationships between deep convection over South America and the atmospheric circulation are examined, with emphasis on submonthly variations of the South Atlantic convergence zone (SACZ) during austral summer. Outgoing longwave radiation (OLR) is used as a proxy for convection, while the associated circulation patterns are depicted by the National Centers for Environmental Prediction Reanalysis. Over South America and the adjacent oceans, OLR fluctuations with periods less than 90 days show maximum variance in the SACZ and over central South America during December-February, There is a local minimum in variance over the southern Amazon Basin, where mean convection is at a maximum. OLR spectra display several statistically relevant peaks corresponding to periods of less than 30 days over tropical South America, with the relative proportion of higher-frequency power increasing as the base grid point is moved to the southeast within the SACZ. Correlations between submonthly (2-30-day) OLR in the vicinity of the SACZ and 200-mb streamfunction reveal the preferred path of Rossby wave energy impinging on the SACZ from the midlatitudes of the Southern Hemisphere. Episodes of enhanced convection within the SACZ, indicated by negative OLR anomalies, occur at the leading edge of upper-level troughs propagating into the region. The corresponding pattern at 850 mb reveals that the disturbances are nearly equivalent barotropic west of South America but tilt westward with height in the region of the SACZ. Negative low-level temperature anomalies lie to the southwest of the convection. The results are consistent with baroclinic development alone an associated cold front. Convection over the southwestern Amazon Basin on submonthly timescales is seen to progress into the region from the south. Upper-level anomalies, which at times may play a role in the initiation of the convection, move eastward and rapidly become decoupled from the convection. Low-level cold air along the eastern flank of the Andes appears linked to the convection as it moves northward. In contrast, convection over the southeastern Amazon is accompanied by disturbances moving into the area from the Atlantic, but there is little sign of a low-level temperature anomaly. In this case convection seems to result in cross-equatorial outflow into the North Atlantic, rather than be the result of forcing from the extratropics. The authors speculate that the relatively stable position of the SACZ is associated with a Rossby wave guide, which ultimately is related to the large-scale circulation driven by sources and sinks of diabetic heating. It also appears that the SACZ forms when the northwesterly how associated with a low-level trough is able to tap moisture from the Amazon. C1 Univ Colorado, NOAA, Cooperat Inst Res Environm Sci, Climate Diagnost Ctr, Boulder, CO 80309 USA. NOAA, Aeron Lab, Boulder, CO 80303 USA. Natl Inst Space Studies, Ctr Weather Forecasts & Climate Studies, Cachoeira Paulista, Brazil. Univ Sao Paulo, Dept Atmospher Sci, Sao Paulo, Brazil. RP Liebmann, B (reprint author), Univ Colorado, NOAA, Cooperat Inst Res Environm Sci, Climate Diagnost Ctr, Campus Box 216, Boulder, CO 80309 USA. RI Marengo, Jose /J-9382-2012; Ambrizzi, Tercio/A-4636-2008 OI Marengo, Jose /0000-0002-8154-2762; NR 41 TC 174 Z9 185 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 PY 1999 VL 12 IS 7 BP 1877 EP 1891 DI 10.1175/1520-0442(1999)012<1877:SCVOSA>2.0.CO;2 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 214WN UT WOS:000081350700001 ER PT J AU Ignatov, A Gutman, G AF Ignatov, A Gutman, G TI Monthly mean diurnal cycles in surface temperatures over land for global climate studies SO JOURNAL OF CLIMATE LA English DT Article ID HIGH-RESOLUTION RADIOMETER; THERMAL INERTIA; SOIL-MOISTURE; INFRARED DATA; AVHRR DATA; SATELLITE; CLOUD; ISCCP; MODEL; EVAPOTRANSPIRATION AB Monthly mean diurnal cycles (MDCs) of surface temperatures over land, represented in 3-h universal time intervals, have been analyzed. Satellite near-global data from the International Satellite Cloud Climatology Project (ISCCP) with a (280 km)(2) resolution (C-2 product) are available for seven individual years and as a climatology derived thereof. Surface 19-yr climatologies on ground and air temperatures, separately for all-sky and clear-sky conditions, matched with the ISCCP data, are employed to better understand satellite-derived MDCs. The MDCs have been converted to local solar time, refined to a regular 1-h time grid using cubic splines, and subjected to principal component analysis. The first two modes approximate MDCs in air and ground-satellite temperatures with rmse's of about sigma = 0.5 degrees and 1 degrees C, respectively, and these accuracies are improved by 20%-35% if the third mode is added. This suggests that two to three temperature measurements during the day allow reconstruction of the full MDC. In the case of two modes, optimal observation times are close to the occurrence of minimum and maximum temperatures, T-min and T-max. The authors provide an empirical algorithm for reconstructing the full MDC using T-min and T-max, and estimate its accuracy. In the analyzed match-up dataset, the statistical structure of ground temperature for ail-sky conditions most closely resembles that of the ISCCP derived temperature. The results are potentially useful for climate- and global-scale studies and applications. C1 NOAA, Natl Environm Satellite Data & Informat Serv, Off Res & Applicat, Climate Res & Applicat Div, Washington, DC 20233 USA. RP Gutman, G (reprint author), NOAA, Natl Environm Satellite Data & Informat Serv, Off Res & Applicat, Climate Res & Applicat Div, E-RA1,4700 Silver Rd,Stop 4700, Washington, DC 20233 USA. RI Ignatov, Alexander/F-5594-2010 OI Ignatov, Alexander/0000-0002-7463-5944 NR 30 TC 15 Z9 16 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 JUL PY 1999 VL 12 IS 7 BP 1900 EP 1910 DI 10.1175/1520-0442(1999)012<1900:MMDCIS>2.0.CO;2 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 214WN UT WOS:000081350700003 ER PT J AU Waliser, DE Jones, C Schemm, JKE Graham, NE AF Waliser, DE Jones, C Schemm, JKE Graham, NE TI A statistical extended-range tropical forecast model based on the slow evolution of the Madden-Julian oscillation SO JOURNAL OF CLIMATE LA English DT Article ID OUTGOING LONGWAVE RADIATION; 40-50 DAY OSCILLATION; SEA-SURFACE TEMPERATURE; NINO-SOUTHERN OSCILLATION; ATMOSPHERE RESPONSE EXPERIMENT; AUSTRALIAN SUMMER MONSOON; INTRASEASONAL TIME SCALES; PACIFIC WARM POOL; TOGA-COARE; EL-NINO AB In this study, a statistical model is developed that exploits the slow evolution of the Madden-Julian oscillation (MJO) to predict tropical rainfall variability at long lead times (i.e., 5-20 days). The model is based on a field-to-field decomposition that uses previous and present pentads of outgoing longwave radiation (OLR: predictors) to predict future pentads of OLR (predictands). The model was developed using 30-70-day bandpassed OLR data from 1979 to 1989 and validated on data from 1990 to 1996. Far the validation period, the model exhibits temporal correlations to observed bandpassed data of about 0.5-0.9 over a significant region of the Eastern Hemisphere at lend times from 5 to 20 days, after which the correlation drops rapidly with increasing lend time. Correlations against observed total anomalies are on the order of 0.3-0.5 over a smaller region of the Eastern Hemisphere. Comparing the skill values from the above OLR-based model, along with those from an identical statistical model using reanalysis-derived 200-mb zonal wind anomalies, to the skill values of 200-mb zonal wind predictions from the National Centers for Environmental Prediction's Dynamic Extended Range Forecasts shows that the statistical models appear to perform considerably better. These results indicate that considerable advantage might be afforded from the further exploration and eventual implementation of MJO-based statistical models to augment current operational long-range forecasts in the Tropics. The comparisons also indicate that there is considerably more work to be done in achieving the likely forecast potential that dynamic models might offer if they could suitably simulate MJO variability. C1 SUNY Stony Brook, Inst Terr & Planetary Atmospheres, MSRC, Stony Brook, NY 11794 USA. Univ Calif Santa Barbara, Inst Computat Earth Syst Sci, Santa Barbara, CA USA. NOAA, Natl Ctr Environm Predict, Climate Predict Ctr, Camp Springs, MD USA. Univ Calif San Diego, Scripps Inst Oceanog, Div Climate Res, Int Res Inst, La Jolla, CA 92093 USA. RP Waliser, DE (reprint author), SUNY Stony Brook, Inst Terr & Planetary Atmospheres, MSRC, Stony Brook, NY 11794 USA. OI Jones, Charles/0000-0003-4808-6977 NR 81 TC 90 Z9 102 U1 0 U2 8 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8755 J9 J CLIMATE JI J. Clim. PD JUL PY 1999 VL 12 IS 7 BP 1918 EP 1939 DI 10.1175/1520-0442(1999)012<1918:ASERTF>2.0.CO;2 PG 22 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 214WN UT WOS:000081350700005 ER PT J AU Enfield, DB Alfaro, EJ AF Enfield, DB Alfaro, EJ TI The dependence of Caribbean rainfall on the interaction of the tropical Atlantic and Pacific oceans SO JOURNAL OF CLIMATE LA English DT Article ID SEA-SURFACE TEMPERATURE; LEVEL PRESSURE ANOMALIES; SOUTHERN-OSCILLATION; VARIABILITY; CLIMATE; CIRCULATION; PRECIPITATION; FREQUENCY; HEIGHT; MODEL AB Seasonally stratified analyses of rainfall anomalies over the intra-Americas sea and surrounding land areas and of onset and end dates of the Central American rainy season show that the variability of the tropical Atlantic sea surface temperature anomaly (SSTA) is more strongly associated with rainfall over the Caribbean and Central America than is tropical eastern Pacific SSTA. Seasonal differences include the importance of antisymmetric configurations of tropical Atlantic SSTA in the dry season but not in the rainy season. Both oceans are related to rainfall, but the strength of the rainfall response appears to depend on how SSTA in the tropical Atlantic and eastern Pacific combine. The strongest response occurs when the tropical Atlantic is in the configuration of a meridional dipole (antisymmetric across the ITCZ) and the eastern tropical Pacific is of opposite sign to the tropical North Atlantic. When the tropical North Atlantic and tropical Pacific are of the same sign, the rainfall response is weaker. The rainy season in lower Central America tends to start early and end late in years that begin with warm SSTs in the tropical North Atlantic, and the end dates are also delayed when the eastern equatorial Pacific is cool. This enhancement of date departures for zonally antisymmetric configurations of SSTA between the North Atlantic and Pacific is qualitatively consistent with;he results for rainfall anomalies. C1 NOAA, Atlantic Oceanog & Meteorol Lab, Miami, FL 33149 USA. Univ Concepcion, Dept Oceanog, Concepcion, Chile. RP Enfield, DB (reprint author), NOAA, Atlantic Oceanog & Meteorol Lab, 4301 Rickenbacker Causeway, Miami, FL 33149 USA. EM enfield@aoml.noaa.gov RI Enfield, David/I-2112-2013; OI Enfield, David/0000-0001-8107-5079; Alfaro, Eric/0000-0001-9278-5017 NR 25 TC 153 Z9 157 U1 0 U2 9 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8755 J9 J CLIMATE JI J. Clim. PD JUL PY 1999 VL 12 IS 7 BP 2093 EP 2103 DI 10.1175/1520-0442(1999)012<2093:TDOCRO>2.0.CO;2 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 214WN UT WOS:000081350700014 ER PT J AU Xu, HHK AF Xu, HHK TI Dental composite resins containing silica-fused ceramic single-crystalline whiskers with various filler levels SO JOURNAL OF DENTAL RESEARCH LA English DT Article DE composite resin; reinforcement mechanism; strength; whisker filler level; polishability ID MECHANICAL-PROPERTIES; FRACTURE-TOUGHNESS; POSTERIOR COMPOSITE; TENSILE-STRENGTH; IN-VITRO; RESTORATIONS; CONVERSION; DEGRADATION; NITRIDE; WEAR AB Currently available direct-filling composite resins are susceptible to fracture and hence are not recommended for use in large stress-bearing posterior restorations involving cusps. The glass fillers in composites provide only limited reinforcement because of the brittleness and low strength of glass. The aim of the present study was to use ceramic single-crystalline whiskers as fillers to reinforce composites, and to investigate the effect of whisker filler level on composite properties. Silica particles were fused onto the whiskers to facilitate silanization and to roughen the whiskers, thereby improving retention in the matrix. The composite flexural strength, elastic modulus, hardness, and degree of polymerization conversion were measured as a function of whisker filler mass fraction, which ranged from 0% to 70%. Selected composites were polished simulating clinical procedures, and the surface roughness was measured with profilometry. The whisker composite with a filler mass fraction of 55% had a flexural strength (mean +/-SD; n = 6) of 196 +/- 10 MPa, significantly higher than 83 +/- 14 MPa of a microfill and 120 +/- 16 MPa of a hybrid composite control (family confidence coefficient = 0.95; Tukey's multiple comparison). The composite modulus and hardness increased monotonically with filler level. The flexural strength first increased, then plateaued with increasing filler level. The degree of conversion decreased with, increasing filler level. The whisker composite had a polished surface roughness similar to that of a conventional hybrid composite (p > 0.1; Student's t). To conclude, ceramic whisker reinforcement can significantly improve the mechanical properties of composite resins;the whisker filler level plays a key role in determining composite properties; and the reinforcement mechanisms appear to be crack pinning by whiskers and friction from whisker pullout resisting crack propagation. 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, Gaithersburg, MD 20899 USA. FU NIDCR NIH HHS [R29 DE12476, P 50 DE09322] NR 44 TC 47 Z9 47 U1 1 U2 7 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 JUL PY 1999 VL 78 IS 7 BP 1304 EP 1311 PG 8 WC Dentistry, Oral Surgery & Medicine SC Dentistry, Oral Surgery & Medicine GA 212GD UT WOS:000081208200004 PM 10403457 ER PT J AU Kotob, SI McLaughlin, SM van Berkum, P Faisal, M AF Kotob, SI McLaughlin, SM van Berkum, P Faisal, M TI Characterization of two Perkinsus spp. from the softshell clam, Mya arenaria using the small subunit ribosomal RNA gene SO JOURNAL OF EUKARYOTIC MICROBIOLOGY LA English DT Article DE phylogenetic relationships; polymerase chain reaction; restriction fragment length polymorphism; riboprinting ID SCALLOPS ARGOPECTEN-IRRADIANS; N-SP APICOMPLEXA; PHYLOGENETIC-RELATIONSHIPS; CRYPTOSPORIDIUM-PARVUM; PHYLUM APICOMPLEXA; FINE-STRUCTURE; PARASITE; SEQUENCES; IDENTIFICATION; MARINUS AB Sequence analysis and riboprinting of the small subunit, ribosomal RNA genes were used to characterize two morphologically different Perkinsus species isolates from the gill (G117) and the hemolymph (H49) of the softshell clam, Mya arenaria. Sequence data of the polymerase chain reaction amplified ribosomal RNA loci of G117 and H49 indicated that these genes are 1803 and 1806 base-pair long, respectively. A sequence similarity of > 98.9% was calculated among ribosomal RNA sequences of the two isolates of this study and the published sequences of Perkinsus marinus from the American eastern oyster, Crassostrea virginica, and Perkinsus sp. from the blood cockle of the Australian mollusc, Anadara trapezia. From a phylogenetic tree obtained from Jukes-Cantor distances of thr aligned ribosomal RNA gene sequences of 13 eukaryotic taxa using the Neighbor-Joining method, we showed that G117 and H49 clustered within the genus Perkinsus. Guided by the sequence data of Perkinsus marinus (accession # X75762) and Perkinsus sp. (accession # L07375), restriction endonucleases were selected for restriction fragment analysis of polymerase chain reaction products of the small subunit ribosomal RNA genes (riboprinting). Riboprinting was used to distinguish the four members of the genus Perkinsus from each other. C1 Virginia Inst Marine Sci, Coll William & Mary, Dept Environm Sci, Gloucester Point, VA 23062 USA. Natl Marine Fisheries Serv, Cooperat Oxford Lab, Oxford, MD 21654 USA. USDA, Beltsville, MD 20705 USA. RP Faisal, M (reprint author), Virginia Inst Marine Sci, Coll William & Mary, Dept Environm Sci, Gloucester Point, VA 23062 USA. NR 33 TC 20 Z9 20 U1 0 U2 2 PU SOC PROTOZOOLOGISTS PI LAWRENCE PA 810 E 10TH ST, LAWRENCE, KS 66044 USA SN 1066-5234 J9 J EUKARYOT MICROBIOL JI J. Eukaryot. Microbiol. PD JUL-AUG PY 1999 VL 46 IS 4 BP 439 EP 444 DI 10.1111/j.1550-7408.1999.tb04625.x PG 6 WC Microbiology SC Microbiology GA 225ED UT WOS:000081944700016 PM 10461386 ER PT J AU Smith, KD McCord, BR MacCrehan, WA Mount, K Rowe, WF AF Smith, KD McCord, BR MacCrehan, WA Mount, K Rowe, WF TI Detection of smokeless powder residue on pipe bombs by micellar electrokinetic capillary electrophoresis SO JOURNAL OF FORENSIC SCIENCES LA English DT Article DE forensic science; smokeless powder; capillary electrophoresis ID CHROMATOGRAPHY; GUNSHOT AB Improvised explosive devices are an increasing concern among law enforcement agencies within the United States because of their destructive capability. Capillary electrophoresis has been used previously for the forensic analysis of inorganic constituents in explosives. Micellar electrokinetic capillary electrophoresis (MECE), also known as micellar electrokinetic chromatography (MEKC), is well suited for the forensic analysis of organic constituents of these materials because of its high sensitivity and small sample requirements. In the present study, pipe bombs filled with known types of smokeless gun powder were detonated under controlled conditions. Samples of explosive residue were collected from the post-blast fragments and analyzed using MECE. The results were compared to the known types and analyzed to investigate the feasibility of matching post-blast residue to a specific powder used as explosive charge. C1 Tennessee Bur Invest, Knoxville, TN 37902 USA. George Washington Univ, Dept Forens Sci, Washington, DC 20052 USA. FBI Lab, Quantico, VA USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Smith, KD (reprint author), Tennessee Bur Invest, 617 W Cumberland Ave,6th Flr, Knoxville, TN 37902 USA. NR 14 TC 58 Z9 60 U1 2 U2 9 PU AMER SOC TESTING MATERIALS PI W CONSHOHOCKEN PA 100 BARR HARBOR DR, W CONSHOHOCKEN, PA 19428-2959 USA SN 0022-1198 J9 J FORENSIC SCI JI J. Forensic Sci. PD JUL PY 1999 VL 44 IS 4 BP 789 EP 794 PG 6 WC Medicine, Legal SC Legal Medicine GA 293AY UT WOS:000085830400025 ER PT J AU Early, EA Cromer, CL Xiong, XX Dummer, DJ O'Brian, TR Parr, AC AF Early, EA Cromer, CL Xiong, XX Dummer, DJ O'Brian, TR Parr, AC TI NIST reference densitometer for visual diffuse transmission density SO JOURNAL OF IMAGING SCIENCE AND TECHNOLOGY LA English DT Article AB The Optical Technology Division of the National Institute of Standards and Technology has developed a new reference densitometer for measuring visual diffuse transmission densities using the diffuse influx mode. This densitometer is used to calibrate both x-ray and photographic film step tablet Standard Reference Materials. The design, characterization, and operation of the densitometer are detailed. The densitometer was fully characterized both to verify compliance with the applicable documentary standards and to determine the combined uncertainty in transmission density associated with the calibrations. C1 Natl Inst Stand & Technol, Opt Technol Div, Gaithersburg, MD 20899 USA. RP Early, EA (reprint author), Natl Inst Stand & Technol, Opt Technol Div, Gaithersburg, MD 20899 USA. NR 15 TC 4 Z9 5 U1 0 U2 0 PU I S & T - SOC IMAGING SCIENCE TECHNOLOGY PI SPRINGFIELD PA 7003 KILWORTH LANE, SPRINGFIELD, VA 22151 USA SN 8750-9237 J9 J IMAGING SCI TECHN JI J. Imaging Sci. Technol. PD JUL-AUG PY 1999 VL 43 IS 4 BP 388 EP 397 PG 10 WC Imaging Science & Photographic Technology SC Imaging Science & Photographic Technology GA 265EK UT WOS:000084228500013 ER PT J AU Varberg, TD Stroh, F Evenson, KM AF Varberg, TD Stroh, F Evenson, KM TI Far-infrared rotational and fine-structure transition frequencies and molecular constants of (NO)-N-14 and (NO)-N-15 in the (XII)-I-2 (nu=0) state SO JOURNAL OF MOLECULAR SPECTROSCOPY LA English DT Article ID RADIOFREQUENCY DOUBLE-RESONANCE; OXIDE FUNDAMENTAL-BAND; NITRIC-OXIDE; DIATOMIC-MOLECULES; SPECTRUM; SPECTROSCOPY; HYPERFINE; NO; PARAMETERS; N-14O-16 AB We have made highly accurate measurements of the absorption spectrum of the (NO)-N-14 and (NO)-N-15 isotopomers of nitric oxide in the far-infrared. Pure rotational transitions up to J " = 371/2 within the (II1/2)-I-2 and (II3/2)-I-2 spin components and several (II3/2)-I-2 <-- (II1/2)-I-2 fine-structure transitions were recorded within the ground vibrational state. A least-squares fit to these data combined with some lambda-doubling and rotational transitions measured by previous workers has resulted in accurate values for the rotational, fine, and hyperfine parameters of these two isotopomers. Most of the far-infrared transitions reported here have an experimental uncertainty of about 20 kHz and will be useful for astronomers and atmospheric scientists studying this important molecule. The more accurate calculated frequencies will also be useful as spectroscopic calibration standards, (C) 1999 Academic Press. C1 Macalester Coll, Dept Chem, St Paul, MN 55105 USA. Forschungszentrum Julich, Inst Stratospher Chem, D-52425 Julich, Germany. Natl Inst Stand & Technol, Div Time & Frequency, Boulder, CO 80303 USA. RP Varberg, TD (reprint author), Macalester Coll, Dept Chem, 1600 Grand Ave, St Paul, MN 55105 USA. RI Stroh, Fred/A-6505-2009 OI Stroh, Fred/0000-0002-4492-2977 NR 28 TC 12 Z9 12 U1 0 U2 3 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0022-2852 J9 J MOL SPECTROSC JI J. Mol. Spectrosc. PD JUL PY 1999 VL 196 IS 1 BP 5 EP 13 DI 10.1006/jmsp.1999.7850 PG 9 WC Physics, Atomic, Molecular & Chemical; Spectroscopy SC Physics; Spectroscopy GA 208RC UT WOS:000081004300002 ER PT J AU Goldberg, RN AF Goldberg, RN TI Thermodynamics of enzyme-catalyzed reactions: Part 6 - 1999 update SO JOURNAL OF PHYSICAL AND CHEMICAL REFERENCE DATA LA English DT Article DE apparent equilibrium constants; enthalpies of reaction; enzyme-catalyzed reactions; evaluated data; transformed thermodynamic properties ID BIOCHEMICAL REACTANTS; SYNTHASE AB This review serves to update previously published evaluations of equilibrium constants and enthalpy changes for enzyme-catalyzed reactions. For each reaction the following information is given: the reference for the data; the reaction studied; the name of the enzyme used and its Enzyme Commission number; the method of measurement; the conditions of measurement [temperature, pH, ionic strength, and the buffer(s) and cofactor(s) used]; the data and an evaluation of it; and, sometimes, commentary on the data and on any corrections which have been applied to it or any calculations for which the data have been used. The data from 96 references have been examined and evaluated. Chemical Abstract Service registry numbers are given for the substances involved in these various reactions. There is also a cross reference between the substances and the Enzyme Commission numbers of the enzymes used to catalyze the reactions in which the substances participate. (C) 1999 American Institute of Physics and American Chemical Society. [S0047-2689(99)00204-4]. C1 Natl Inst Stand & Technol, Div Biotechnol, Gaithersburg, MD 20899 USA. RP Goldberg, RN (reprint author), Natl Inst Stand & Technol, Div Biotechnol, Gaithersburg, MD 20899 USA. NR 25 TC 31 Z9 32 U1 1 U2 5 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0047-2689 J9 J PHYS CHEM REF DATA JI J. Phys. Chem. Ref. Data PD JUL-AUG PY 1999 VL 28 IS 4 BP 931 EP 965 DI 10.1063/1.556041 PG 35 WC Chemistry, Multidisciplinary; Chemistry, Physical; Physics, Multidisciplinary SC Chemistry; Physics GA 263RF UT WOS:000084138500002 ER PT J AU Christophorou, LG Olthoff, JK AF Christophorou, LG Olthoff, JK TI Electron interactions with plasma processing gases: An update for CF4, CHF3, C2F6, and C3F8 SO JOURNAL OF PHYSICAL AND CHEMICAL REFERENCE DATA LA English DT Article DE attachment; CF4; C2F6; C3F8; CHF3; cross sections; dissociation; electron interactions; ionization; scattering; transport coefficients ID CROSS-SECTION MEASUREMENTS; MODIFIED ADDITIVITY RULE; LOW-ENERGY ELECTRONS; ATTACHMENT COEFFICIENTS; CARBON TETRAFLUORIDE; IMPACT DISSOCIATION; IONIZATION; SCATTERING; MOLECULES; IONS AB An update of electron-collision cross sections and electron transport parameters is presented for CF4, CHF3, C2F6, and C3F8. (C) 1999 American Institute of Physics and American Chemical Society. [S0047-2689(99)00104-X]. C1 Natl Inst Stand & Technol, Div Elect, Elect & Elect Engn Lab, Gaithersburg, MD 20899 USA. RP Christophorou, LG (reprint author), Natl Inst Stand & Technol, Div Elect, Elect & Elect Engn Lab, Gaithersburg, MD 20899 USA. NR 75 TC 122 Z9 123 U1 3 U2 20 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0047-2689 J9 J PHYS CHEM REF DATA JI J. Phys. Chem. Ref. Data PD JUL-AUG PY 1999 VL 28 IS 4 BP 967 EP 982 DI 10.1063/1.556042 PG 16 WC Chemistry, Multidisciplinary; Chemistry, Physical; Physics, Multidisciplinary SC Chemistry; Physics GA 263RF UT WOS:000084138500003 ER PT J AU Kegley-Owen, CS Gilles, MK Burkholder, JB Ravishankara, AR AF Kegley-Owen, CS Gilles, MK Burkholder, JB Ravishankara, AR TI Rate coefficient measurements for the reaction OH+ClO -> products SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID TEMPERATURE-DEPENDENCE; BRANCHING RATIO; RATE-CONSTANT; 248 NM; CLO; KINETICS; OH; HO2; PHOTODISSOCIATION; RADICALS AB The rate coefficient for the reaction OH + ClO --> products (1) was measured under pseudo-first-order conditions in OH. A discharge flow system was used to produce ClO, and its concentration was measured by UV/visible absorption. OH was produced by pulsed laser photolysis of O-3 (or ClO) at 248 nm in the presence of H2O and was monitored by laser-induced fluorescence. The value of k(1) between 234 and 356 K is given by k(1)(T) = (8.9 +/- 2.7) x 10(-12) exp[(295 +/- 95)/T] cm(3) molecule(-1) s(-1), where uncertainties are 95% confidence limits and include estimated systematic uncertainties. Our value is compared with those from previous investigations. C1 NOAA, Aeron Lab, Boulder, CO 80303 USA. Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. RP Gilles, MK (reprint author), NOAA, ERL, R-E-AL2,325 Broadway, Boulder, CO 80303 USA. RI Burkholder, James/H-4914-2013; Ravishankara, Akkihebbal/A-2914-2011 NR 22 TC 25 Z9 25 U1 0 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD JUL 1 PY 1999 VL 103 IS 26 BP 5040 EP 5048 DI 10.1021/jp9904320 PG 9 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 215YK UT WOS:000081412800011 ER PT J AU Jungclaus, JH AF Jungclaus, JH TI A three-dimensional simulation of the formation of anticyclonic lenses (meddies) by the instability of an intermediate depth boundary current SO JOURNAL OF PHYSICAL OCEANOGRAPHY LA English DT Article ID MEDITERRANEAN SALT LENS; WATER; STABILITY; OCEAN; MODEL; ATLANTIC; MOVEMENT; OUTFLOW; SHELF; FLUID AB The evolution of a buoyancy-driven intermediate water current along an idealized continental slope is investigated using a three-dimensional primitive equation ocean model. The outflow current, originating in a marginal sea, flows northward along a linear sloping bottom where it undergoes considerable mixing. For a parameter range resembling the Mediterranean outflow, the flow becomes hydrodynamically unstable. The intruding, relatively dense outflow water interacts with the overlaying slope water by inducing vortex compression and stretching. The phase relation between the upper-layer and lower-layer perturbations indicates that baroclinic instability is the driving mechanism in the initial destabilization. As the disturbances grow to large amplitude, dipoles are formed and move away from the boundary current in a westward direction. While the amplifying anticyclones wrap around the intruding low potential vorticity water, the cyclones usually entrain ambient water and decrease in strength. Isolated anticyclones finally separate from the boundary current and develop a southward translation component. In some cases dipolar structures remain intact and propagate to the west. In the slope water strong cyclones and somewhat weaker anticyclones are formed periodically and travel in the direction of the bottom flow. The upper-layer flow shows surface expressions of the middepth lenses that develop as meddles. These penetrate into the ambient slope water and gain a barotropic velocity component. The adjustment process is discussed in terms of potential vorticity conservation. The instability mechanism discussed here does not require any topographic irregularities. Sensitivity experiments, however, suggest that canyons or capes introduce an additional source of vorticity and may lead to the observed localization of spawning events. C1 Princeton Univ, Program Atmospher & Ocean Sci, Princeton, NJ 08544 USA. RP Jungclaus, JH (reprint author), Max Planck Inst Meteorol, Bundesstr 55, D-20146 Hamburg, Germany. EM jungclaus@dkrz.de NR 46 TC 23 Z9 23 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-3670 EI 1520-0485 J9 J PHYS OCEANOGR JI J. Phys. Oceanogr. PD JUL PY 1999 VL 29 IS 7 BP 1579 EP 1598 DI 10.1175/1520-0485(1999)029<1579:ATDSOT>2.0.CO;2 PG 20 WC Oceanography SC Oceanography GA 221RB UT WOS:000081739100013 ER PT J AU Cage, ME Jeffery, A AF Cage, ME Jeffery, A TI Analyzing the effects of capacitances-to-shield in sample probes on AC quantized Hall resistance measurements SO JOURNAL OF RESEARCH OF THE NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY LA English DT Article DE ac quantum Hall effect; capacitance-to-shield; equivalent electrical circuit; longitudinal resistance; multi-series connections; quantized Hall resistance ID STANDARDS AB We analyze the effects of the large capacitances-to-shields existing in all sample probes on measurements of the ac quantized Hall resistance R-H. The object of this analysis is to investigate how these capacitances affect the observed frequency dependence of R-H. Our goal is to see if there is some way to eliminate or minimize this significant frequency dependence, and thereby realize an intrinsic ac quantized Hall resistance standard. Equivalent electrical circuits are used in this analysis, with circuit components consisting of capacitances and leakage resistances to the sample probe shields; inductances and resistances of the sample probe leads; quantized Hall resistances, longitudinal resistances, and voltage generators within the quantum Hall effect device; and multiple connections to the device. We derive exact algebraic equations for the measured R-H values expressed in terms of the circuit components. Only two circuits (with single-series "offset" and quadruple-series connections) appear to meet our desired goals of measuring both R-H and the longitudinal resistance R-x in the same cool-down for both ac and de currents with a one-standard-deviation uncertainty of 10(-8) R-H or less. These two circuits will be further considered in a future paper in which the effects of wire-to-wire capacitances are also included in the analysis. C1 NIST, Elect & Elect Engn Lab, Div Elect, Gaithersburg, MD 20899 USA. RP Cage, ME (reprint author), NIST, Elect & Elect Engn Lab, Div Elect, Gaithersburg, MD 20899 USA. NR 25 TC 2 Z9 2 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 1999 VL 104 IS 4 BP 323 EP 347 DI 10.6028/jres.104.023 PG 25 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 247JB UT WOS:000083216700001 ER PT J AU McCaleb, MR AF McCaleb, MR TI A conceptual data model of datum systems SO JOURNAL OF RESEARCH OF THE NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY LA English DT Article DE data model; datum feature; datum addresses; datum system; datum target AB A new conceptual data model that addresses the geometric dimensioning and tolerancing concepts of datum systems, datums, datum features, datum targets, and the relationships among these concepts, is presented. Additionally, a portion of a and the relationships among these concepts, related data model, Part 47 of STEP (ISO 10303-47), is reviewed and a comparison is made between it and the new conceptual data model. C1 NIST, Elect & Elect Engn Lab, Div Elect, Gaithersburg, MD 20899 USA. RP McCaleb, MR (reprint author), NIST, Elect & Elect Engn Lab, Div Elect, Gaithersburg, MD 20899 USA. NR 16 TC 0 Z9 0 U1 0 U2 0 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 1999 VL 104 IS 4 BP 349 EP 400 DI 10.6028/jres.104.024 PG 52 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 247JB UT WOS:000083216700002 ER PT J AU Millburn, JE Green, MA Neumann, DA Rosseinsky, MJ AF Millburn, JE Green, MA Neumann, DA Rosseinsky, MJ TI Evolution of the structure of the K2NiF4 phases La2-xSrxNiO4+delta with oxidation state: Octahedral distortion and phase separation (0.2 <= x <= 1.0) SO JOURNAL OF SOLID STATE CHEMISTRY LA English DT Article; Proceedings Paper CT Symposium on Electronic Processes in Inorganic Compounds in honor of Peter Day's 60th Birthday CY JUN, 1998 CL ENGLAND SP Royal Inst Great Britian ID ELECTRON-TRANSPORT PROPERTIES; BOND-VALENCE PARAMETERS; NEUTRON-DIFFRACTION; MAGNETIC-PROPERTIES; CRYSTAL-CHEMISTRY; CHARGE; LA2NIO4; PEROVSKITE; POLARONS; LA2-XSRXCUO4 AB The structural properties of the La2-xSrxNiO4+delta solid solution have been investigated by high resolution powder neutron diffraction as a function of Sr dopant concentration. There is a significant change in the evolution of the shape of the NiO6 octahedron beyond x = 0.6, where previous transport measurements have indicated a transition in the electronic structure. For the x = 1 member of the series prepared under conditions often adopted in the literature, a subtle inhomogeneity is visible in the high-resolution powder diffraction patterns and interpreted as arising from a distribution of La/Sr ratios throughout the sample under these widely used preparative conditions. The refined model, incorporating both strain broadening and Bragg peak displacement, can be interpreted as a continuum of phases with differing c, but similar a, lattice parameters. Preparation of LaSrNiO4+delta at 1450 degrees C appears to overcome this effect but Rietveld refinement is only possible with the aid of hkl dependent line broadening analysis, in contrast to the other members of the series studied. (C) 1999 Academic Press. C1 Univ Oxford, Inorgan Chem Lab, Dept Chem, Oxford OX1 3QR, England. Natl Inst Stand & Technol, Ctr Neutron Res, Gaithersburg, MD 20899 USA. RP Millburn, JE (reprint author), Univ Oxford, Inorgan Chem Lab, Dept Chem, S Parks Rd, Oxford OX1 3QR, England. NR 52 TC 27 Z9 28 U1 0 U2 13 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 1999 VL 145 IS 2 BP 401 EP 420 DI 10.1006/jssc.1999.8111 PG 20 WC Chemistry, Inorganic & Nuclear; Chemistry, Physical SC Chemistry GA 216YZ UT WOS:000081473200006 ER PT J AU Abdulagatov, IM Dvoryanchikov, VI Kamalov, AN Abramova, EG AF Abdulagatov, IM Dvoryanchikov, VI Kamalov, AN Abramova, EG TI Constant-volume heat capacity of H2O+Na2CO3 solutions near the critical point of pure water SO JOURNAL OF SOLUTION CHEMISTRY LA English DT Article DE aqueous electrolytes; coexistence curve; critical point; isochoric heat capacity; sodium carbonate; supercritical solution; water ID EQUATION; NACL-H2O; STATE; H2O AB The results of new isochoric heat capacity measurements of H2O + Na2CO3 solutions as a function of temperature along several isochores in the near-critical region of pure water are reported. The measurements cower temperatures from 331 to 661 K at Na2CO3 mole fraction 0.008869. The experiments were performed at seven densities between 245 and 875 kg-m(-3). The measurements were made in a high-temperature, high-pressure, adiabatic, and nearly constant-volume calorimeter. Uncertainties of the isochoric heat capacity measurements are estimated to be 1-2% in the liquid phase, 2-3% in the vapor phase, and 4-5% near the critical point. Measurements were made in the two-phase (vapor-liquid, liquid-solid, vapor-solid) and three-phase (vapor-liquid-solid) regions. Two peaks in isochoric heat capacity have been found near the critical point of pure water. One of the peaks at T-S1 occurs on the three-phase (L-V-S) curve and another peak at T-S2 corresponds to a two-phase (L-S or V-S) curve. The experimental values of phase transition temperatures T-S(rho) on each isochore was determined. Uncertainty in the phase transition temperature measured was no greater than +/-0.03 to 0.05 K. C1 Natl Inst Stand & Technol, Phys & Chem Properties Div, Boulder, CO 80303 USA. Russian Acad Sci, Inst Geothermal Problems, Dagestan Sci Ctr, Makhachkala 367030, Dagestan, Russia. RP Abdulagatov, IM (reprint author), Natl Inst Stand & Technol, Phys & Chem Properties Div, 325 Broadway, Boulder, CO 80303 USA. NR 20 TC 1 Z9 2 U1 0 U2 0 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0095-9782 J9 J SOLUTION CHEM JI J. Solut. Chem. PD JUL PY 1999 VL 28 IS 7 BP 865 EP 883 DI 10.1023/A:1021784231509 PG 19 WC Chemistry, Physical SC Chemistry GA 233AY UT WOS:000082404400004 ER PT J AU Mehl, JB AF Mehl, JB TI Greenspan acoustic viscometer: Numerical calculations of fields and duct-end effects SO JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA LA English DT Article ID CIRCULAR PIPE; IMPEDANCE AB Inertial and resistive end corrections for the Greenspan acoustic viscometer were computed using a boundary-integral-equation technique for determination of the acoustic field. Viscous effects were estimated using a boundary-layer approximation. The results apply to a circular duct coupling two concentric chambers and to ducts terminated by infinite plane baffles. The effects of rounding the sharp edge at the duct end were investigated and found to be described by simple scaling relations. (C) 1999 Acoustical Society of America. [S0001-4966(99)05507-1]. C1 Natl Inst Stand & Technol, Phys & Chem Properties Div, Gaithersburg, MD 20899 USA. Univ Delaware, Dept Phys & Astron, Newark, DE 19711 USA. RP Mehl, JB (reprint author), Natl Inst Stand & Technol, Phys & Chem Properties Div, Gaithersburg, MD 20899 USA. NR 29 TC 12 Z9 12 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0001-4966 J9 J ACOUST SOC AM JI J. Acoust. Soc. Am. PD JUL PY 1999 VL 106 IS 1 BP 73 EP 82 DI 10.1121/1.428149 PG 10 WC Acoustics; Audiology & Speech-Language Pathology SC Acoustics; Audiology & Speech-Language Pathology GA 217AK UT WOS:000081476700007 ER PT J AU Norris, TF Mc Donald, M Barlow, J AF Norris, TF Mc Donald, M Barlow, J TI Acoustic detections of singing humpback whales (Megaptera novaeangliae) in the eastern North Pacific during their northbound migration SO JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA LA English DT Article; Proceedings Paper CT 134th Meeting of the Acoustical-Society-of-America CY DEC 01-05, 1997 CL SAN DIEGO, CALIFORNIA SP Acoust Soc Amer ID CALIFORNIA WATERS; MEXICAN PACIFIC; WEST-INDIES; SONGS; ABUNDANCE; CETACEANS; SEX; MOVEMENT; GROUNDS; HABITAT AB Numerous (84) acoustic detections of singing humpback whales were made during a spring (08 March-09 June 1997) research cruise to study sperm whales in the central and eastern North Pacific. Over 15000 km of track-line was surveyed acoustically using a towed hydrophone array. Additionally, 83 sonobuoys were deployed throughout the study area. Detection rates were greatest in late March, near the Hawaiian Islands, and in early April, northeast of the islands. Only one detection was made after April. Detection rates for sonobuoys were unequal in three equally divided longitudinal regions of the study area. Two high density clusters of detections occurred approximately 1200-2000 km northeast of the Hawaiian Islands and were attributed to a large aggregation of migrating animals. The distribution of these detections corroborates findings of previous studies. It is possible that these animals were maintaining acoustic contact during migration. Two unexpected clusters of singing whales were detected approximately 900 to 1000 km west of central and southern California. The location of these detections may indicate a previously undocumented migration route between an offshore breeding area, such as the Revillagigedo Islands, Mexico, and possible feeding areas in the western North Pacific or Bering Sea. (C) 1999 Acoustical Society of America. [S0001-4966(99)03706-6]. C1 SW Fisheries Sci Ctr, La Jolla, CA 92038 USA. RP Norris, TF (reprint author), Sci Applicat Int Corp, Maritime Serv, 3990 Old Town Ave,Suite 105A, San Diego, CA 92110 USA. NR 63 TC 46 Z9 47 U1 1 U2 15 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0001-4966 J9 J ACOUST SOC AM JI J. Acoust. Soc. Am. PD JUL PY 1999 VL 106 IS 1 BP 506 EP 514 DI 10.1121/1.427071 PG 9 WC Acoustics; Audiology & Speech-Language Pathology SC Acoustics; Audiology & Speech-Language Pathology GA 217AK UT WOS:000081476700048 PM 10420640 ER PT J AU Bapna, MS Mueller, HJ AF Bapna, MS Mueller, HJ TI Thermodilatometric characterization for devitrification of a micaceous dental glass-ceramic SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Article ID STRUCTURAL RELAXATION; ACTIVATION-ENERGY; DICOR(R) GLASS; CRYSTALLIZATION; KINETICS; PORCELAIN AB The devitrification of an uncerammed micaceous glass-ceramic used for dental applications was studied by thermodilatometry and compared with the kinetics of mica crystallization studied by differential thermal analysis. The thermodilatometry plots and their derivative plots revealed thermally impeded processes, namely, structural relaxation, glass softening and nucleation, and crystallization, and they were characterized by glass-transition temperature, glass-softening temperatures, and crystallization temperature. The heating-rate dependence for these characteristic temperatures was used to determine the activation energy for structural relaxation of 338 kJ . mol(-1), the activation energy for viscous flow of 276 kJ . mol(-1), and the apparent activation energy for crystallization of 286 kJ . mol(-1) by one model and 342 kJ . mol(-1) by another model. The similar magnitudes for these activation energies suggested the mechanisms for different thermal processes involved analogous molecular motions, Furthermore, the activation energy for crystallization of the micaceous phase of the glass-ceramic could be estimated from thermodilatometry plots, because it was comparable in magnitude to that obtained from the widely used nonisothermal differential thermal analysis method. Finally, the dilatometry and scanning electron microscopy studies strengthened the earlier opinion that the devitrification of the base glass is a single-step process, that is, without occurrence of an intermediate phase before the formation of the final crystalline phase. C1 Univ Illinois, Coll Dent, Div Biomat Technol, Chicago, IL 60612 USA. Natl Inst Stand & Technol, Amer Dent Assoc Hlth Fdn, Paffenbarger Res Ctr, Gaithersburg, MD 20899 USA. RP Bapna, MS (reprint author), Univ Illinois, Coll Dent, Div Biomat Technol, Chicago, IL 60612 USA. NR 33 TC 3 Z9 3 U1 0 U2 2 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 1999 VL 82 IS 7 BP 1771 EP 1776 PG 6 WC Materials Science, Ceramics SC Materials Science GA 215ZY UT WOS:000081416900017 ER PT J AU Fischer-Cripps, AC AF Fischer-Cripps, AC TI A "partitioned-problem" approach to microstructural modeling of a glass-ceramic SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Article ID HERTZIAN CONTACTS; POLYCRYSTALLINE CERAMICS; SILICON-CARBIDE; FATIGUE; DUCTILE; DAMAGE; MICA AB The indentation response of a mica-containing glass-ceramic is studied. In this type of material, Hertzian cone cracks, which normally occur in brittle materials that have been loaded with a hard spherical indenter, are suppressed in favor of distributed subsurface damage, which is indicative of yield. Theoretical analysis, finite-element modeling, and experimental results are used to establish a connection between the macroscopic behavior of the material and events that occur on a microstructural scale. This association is achieved by first determining the macroscopic material properties, such as the yield stress and the strain-hardening index, in terms of the microstructure, Then, these properties are used to predict the macroscopic indentation response of the material. Thus, the problem is partitioned into microstructural and macroscopic domains. This work is particularly relevant to the design of structural ceramics in machining, wear, and bearings applications. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP CSIRO, Div Telecommun & Ind Phys, Sydney, NSW 2070, Australia. NR 36 TC 4 Z9 4 U1 0 U2 2 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 JUL PY 1999 VL 82 IS 7 BP 1835 EP 1843 PG 9 WC Materials Science, Ceramics SC Materials Science GA 215ZY UT WOS:000081416900025 ER PT J AU Blendell, JE Carter, WC Handwerker, CA AF Blendell, JE Carter, WC Handwerker, CA TI Faceting and wetting transitions of anisotropic interfaces and grain boundaries SO JOURNAL OF THE AMERICAN CERAMIC SOCIETY LA English DT Article ID EQUILIBRIUM CRYSTAL SHAPES; VECTOR THERMODYNAMICS; PHASE-EQUILIBRIA; ALUMINUM-OXIDE; SURFACES; GLASS; CERAMICS AB A three-dimensional construction is presented that illustrates conditions under which anisotropic interfaces will be fully wetted, partially wetted, or not wetted by a second phase. Recent experimental observations on the equilibrated morphologies of solid or fluid "wetting" phases along anisotropic interfaces and grain boundaries reveal features that are predicted-and, in some cases, required-by the construction. Theory distinguishes between cases where surfaces are smoothly curved and where there are facets, edges, and corners. In the latter case, the conventional comparison of the surface energy of the original surface with the sum of the surface energy of the two surfaces of the wetting layer leads to erroneous predictions. The correct predictions are obtained by comparing the Wulff shape of the original surface with a carefully defined "sum" of Wulff shapes of the surfaces of the wetting layer, Where orientations that are wetted join with those that are not, an abrupt change of orientation usually is present. Faceting on two hierarchical levels can occur. Microscopic morphology changes along macroscopically curved surfaces follow well-defined rules that are predicted by the theory, The analogy between the thermodynamics of surface faceting and phase transformations allows the well-known concepts of phase equilibria to be used to understand the predicted structures. C1 Natl Inst Stand & Technol, Mat Sci & Engn Lab, Gaithersburg, MD 20899 USA. RP Blendell, JE (reprint author), Natl Inst Stand & Technol, Mat Sci & Engn Lab, Gaithersburg, MD 20899 USA. RI Carter, W/K-2406-2012 NR 24 TC 37 Z9 37 U1 3 U2 14 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 1999 VL 82 IS 7 BP 1889 EP 1900 PG 12 WC Materials Science, Ceramics SC Materials Science GA 215ZY UT WOS:000081416900032 ER PT J AU Adlerman, EJ Droegemeier, KK Davies-Jones, R AF Adlerman, EJ Droegemeier, KK Davies-Jones, R TI A numerical simulation of cyclic mesocyclogenesis SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID ROTATING CONVECTIVE STORMS; SUPERCELL THUNDERSTORM; TORNADIC STORMS; ENVIRONMENTS; PROPAGATION; SHEAR; ENERGETICS; VORTICITY; EVOLUTION; HELICITY AB A three-dimensional nonhydrostatic numerical model, the Advanced Regional Prediction System, is used to study the process of cyclic mesocyclogenesis in a classic supercell thunderstorm. During the 4-h simulation, the storm's mesocyclone undergoes two distinct occlusions, with the beginning of a third indicated at the end of the simulation. The occlusion process exhibits a period of approximately 60 min and is qualitatively similar in each case. Initial midlevel (3-7 km) mesocyclogenesis proceeds according to the "classic" picture, that is, via tilting of streamwise environmental vorticity. The development of an evaporatively driven rear-flank downdraft (RFD) signals the beginning of the occlusion process. The developing RFD wraps cyclonically around the mesocyclone, causing the gust front to surge outward. Simultaneously, the occluding mesocyclone rapidly intensifies near the surface. Trajectory analyses demonstrate that this intensification follows from the tilting and stretching of near-ground (<500 m) streamwise vorticity produced by baroclinic generation, crosswise exchange, and streamwise stretching along descending parcel trajectories in the RFD. The surging gust front also initiates updraft development on the downshear flank at midlevels, resulting in a two-celled updraft structure. As the near-ground mesocyclone becomes detached from the gust front due to the developing occlusion downdraft, the upshear updraft flank weakens as its conditionally unstable inflow is cut off at low levels; at the same time, the downshear updraft flank continues to develop eastward. The end of the occlusion process is signaled as the old near-ground mesocyclone becomes completely embedded near the surface in divergent outflow beneath the decaying updraft and is advected away by the mean flow. Near-ground mesocyclogenesis is initiated in the new updraft in a process nearly identical to that of the initial mesocyclone. However, after the first occlusion, near-ground equivalent potential temperature and buoyancy contours are fortuitously oriented such that streamwise baroclinic generation can proceed without delay. Thus, although the initial occlusion requires two hours to become fully organized, the second occurs only one hour later In effect, the occlusion appears to set the stage for more rapid development of subsequent mesocyclones. C1 Univ Oklahoma, Sch Meteorol, Norman, OK 73019 USA. Univ Oklahoma, Ctr Anal & Predict Storms, Norman, OK 73019 USA. NOAA, Natl Severe Storms Lab, Norman, OK 73069 USA. RP Adlerman, EJ (reprint author), Univ Oklahoma, Sch Meteorol, 100 E Boyd St,Rm 1310, Norman, OK 73019 USA. NR 57 TC 85 Z9 85 U1 0 U2 2 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 1999 VL 56 IS 13 BP 2045 EP 2069 DI 10.1175/1520-0469(1999)056<2045:ANSOCM>2.0.CO;2 PG 25 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 213DG UT WOS:000081256400001 ER PT J AU Powell, CJ Jablonski, A AF Powell, CJ Jablonski, A TI Consistency of calculated and measured electron inelastic mean free paths SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS LA English DT Article; Proceedings Paper CT 45th International Symposium of the American-Vacuum-Society CY NOV 02-06, 1998 CL BALTIMORE, MARYLAND SP Amer Vacuum Soc ID RAY-PHOTOELECTRON-SPECTROSCOPY; LOW-ENERGY ELECTRONS; ATTENUATION LENGTHS; ALKALI-HALIDES; SOLIDS; RANGE; OXIDES; METALS; MODEL; IMFP AB We present an evaluation of the consistency of calculated and measured electron inelastic mean free paths (IMFPs) for seven elemental solids (Al, Si, Ni, Cu, Ge, Ag, and An). These solids were selected because, for each, there were two or more independent IMFP calculations and two or more IMFP measurements by elastic-peak electron spectroscopy. We found that the calculated IMFPs for each element showed a high degree of consistency and that there was greater scatter among the measured IMFPs. Comparison of the measured IMFPs with the calculated IMFPs showed generally good agreement. The greatest consistency in the comparisons was: found for Ni, Cu, Ag, and Au. Recommended values of the IMFPs for these four elements can be obtained from a single formula (used to fit the calculated IMFPs for each element) for electron energies between 50 and 10(4) eV. (C) 1999 American Vacuum Society. [S0734-2101(99)02904-8]. C1 Natl Inst Stand & Technol, Surface & Microanal Sci Div, Gaithersburg, MD 20899 USA. Polish Acad Sci, Inst Phys Chem, PL-01224 Warsaw, Poland. RP Powell, CJ (reprint author), Natl Inst Stand & Technol, Surface & Microanal Sci Div, Gaithersburg, MD 20899 USA. NR 40 TC 15 Z9 15 U1 5 U2 5 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0734-2101 J9 J VAC SCI TECHNOL A JI J. Vac. Sci. Technol. A-Vac. Surf. Films PD JUL-AUG PY 1999 VL 17 IS 4 BP 1122 EP 1126 DI 10.1116/1.581784 PN 1 PG 5 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA 217DX UT WOS:000081485700009 ER PT J AU Fry, RA Bennett, LH Della Torre, E AF Fry, RA Bennett, LH Della Torre, E TI Reversal behavior in a bimodal magneto-optical medium SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS LA English DT Article; Proceedings Paper CT 45th International Symposium of the American-Vacuum-Society CY NOV 02-06, 1998 CL BALTIMORE, MARYLAND SP Amer Vacuum Soc ID BEAM-EPITAXIAL-GROWTH; THIN-FILMS; MAGNETIZATION REVERSAL; 111 AXES; MULTILAYERS; ANISOTROPY; KERR AB Bimodal magnetic behavior, in which Kerr rotation (theta(K)), and ellipticity (epsilon(K)) each exhibit major magneto-optic hysteresis loops with two distinct field-dependent steps, was encountered in a (0.3 nm Co/1.2 nm Pt)(15) multilayer film with perpendicular magnetization. A model is postulated in which there are two different interacting magnetic entities present in the layered structure of this material, each with a stable perpendicular magnetization state either parallel or antiparallel to the applied field, and which reverse quasi-independently from one another. Due to interactions between the two, the reversals occur at the intrinsic coercivities displaced by an interaction field, H-i, whose sign depends upon the magnetization of the other phase. Using major loop and,first-order reversal measurements, the intrinsic coercivities, as well as H-i, were obtained. (C) 1999 American Vacuum Society. [S0734-2101(99)19704-5]. C1 George Washington Univ, Inst Magnet Res, Ashburn, VA 20147 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Fry, RA (reprint author), George Washington Univ, Inst Magnet Res, Ashburn, VA 20147 USA. NR 17 TC 2 Z9 2 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0734-2101 J9 J VAC SCI TECHNOL A JI J. Vac. Sci. Technol. A-Vac. Surf. Films PD JUL-AUG PY 1999 VL 17 IS 4 BP 1331 EP 1334 DI 10.1116/1.581816 PN 1 PG 4 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA 217DX UT WOS:000081485700047 ER PT J AU Olthoff, JK Wang, YC AF Olthoff, JK Wang, YC TI Studies of ion bombardment in high density plasmas containing CF4 SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS LA English DT Article; Proceedings Paper CT 45th International Symposium of the American-Vacuum-Society CY NOV 02-06, 1998 CL BALTIMORE, MARYLAND SP Amer Vacuum Soc ID RADIOFREQUENCY REFERENCE CELL; INDUCTIVELY-COUPLED PLASMA; RF REFERENCE CELL; ENERGY-DISTRIBUTIONS; PARALLEL-PLATE; DISCHARGES; ARGON; GAS AB We report ion energy distributions, relative ion intensities, and absolute total ion current densities at the grounded electrode of an inductively coupled Gaseous Electronics Conference radio-frequency reference cell for discharges generated in pure CF4, and in CF4:Ar and CF4:O-2:Ar mixtures. Abundant ionic species, including secondary ions such as CO+ and COF+, were observed and their implications are discussed. [S0734-2101(99)03204-2]. C1 Natl Inst Stand & Technol, Div Elect, Elect & Elect Engn Lab, Gaithersburg, MD 20899 USA. RP Olthoff, JK (reprint author), Natl Inst Stand & Technol, Div Elect, Elect & Elect Engn Lab, Gaithersburg, MD 20899 USA. NR 21 TC 44 Z9 45 U1 0 U2 0 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0734-2101 J9 J VAC SCI TECHNOL A JI J. Vac. Sci. Technol. A-Vac. Surf. Films PD JUL-AUG PY 1999 VL 17 IS 4 BP 1552 EP 1555 DI 10.1116/1.581851 PN 1 PG 4 WC Materials Science, Coatings & Films; Physics, Applied SC Materials Science; Physics GA 217DX UT WOS:000081485700085 ER PT J AU Egelhoff, WF Chen, PJ Powell, CJ Parks, D Serpa, G McMichael, RD Martien, D Berkowitz, AE AF Egelhoff, WF Chen, PJ Powell, CJ Parks, D Serpa, G McMichael, RD Martien, D Berkowitz, AE TI Specular electron scattering in metallic thin films SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B LA English DT Article; Proceedings Paper CT 26th Annual Conference on the Physics and Chemistry of Semiconductor Interfaces (PCSI 26) CY JAN 17-21, 1999 CL SAN DIEGO, CALIFORNIA ID BY-LAYER GROWTH; MAGNETORESISTANCE SPIN VALVES; AG CAPPING LAYER; GIANT MAGNETORESISTANCE; ENHANCED MAGNETORESISTANCE; HOMOEPITAXIAL GROWTH; EXCHANGE-ANISOTROPY; QUANTUM-SIZE; NIO; SURFACTANT AB Specular electron scattering at the surface of metallic thin films is an important phenomenon for a class of magnetic multilayers known as giant magnetoresistance (GMR) spin valves. In the very best GMR spin valves, a significant part of the GMR effect is attributable to specular electron scattering. We have investigated the importance of specular electron scattering by developing surface-modification techniques that produce diffuse electron scattering. We have used these techniques to investigate specular electron scattering in GMR spin valves and in pure metals. Some of the largest effects are found in Au films. It is noted that specular electron scattering will be a highly desirable property in future generations of microelectronic interconnects as the feature size approaches the mean free path of the conduction electrons. In order to meet the Semiconductor Industry Association Roadmap requirements for interconnect resistivity, interconnects with highly specular surfaces must be developed. (C) 1999 American Vacuum Society. [S0734-211X(99)08204-9]. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Univ Calif San Diego, La Jolla, CA 92093 USA. RP Egelhoff, WF (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RI McMichael, Robert/J-8688-2012 NR 38 TC 24 Z9 27 U1 2 U2 8 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 1071-1023 J9 J VAC SCI TECHNOL B JI J. Vac. Sci. Technol. B PD JUL-AUG PY 1999 VL 17 IS 4 BP 1702 EP 1707 DI 10.1116/1.590812 PG 6 WC Engineering, Electrical & Electronic; Nanoscience & Nanotechnology; Physics, Applied SC Engineering; Science & Technology - Other Topics; Physics GA 227LW UT WOS:000082082700067 ER PT J AU Lee, DH AF Lee, DH TI Institutional and technical barriers to risk-based water resources management: A case study SO JOURNAL OF WATER RESOURCES PLANNING AND MANAGEMENT-ASCE LA English DT Article ID FORECASTS AB Implementing risk-based Great Lakes water level management and forecasting, as recommended by the International Joint Commission, would allow managers and other interests affected by fluctuating water levels to consider the wide range of potential future lake levels, incorporate some of the uncertainty inherent in forecasts, and allow explicit consideration of risk. Decision making that requires knowledge of future lake levels would potentially improve, resulting in economic and environmental benefits. Significant institutional and technical barriers preventing implementation exist, among them the lack of International Joint Commission authority to mandate other agencies to implement its recommendations, and the lack of objective evidence that risk-based water level management is an improvement over current procedures. Strategies for overcoming these and other barriers are suggested. The barriers and strategies specific to this case study are generalized so that other water resource managers may consider them when applying risk-based management to their systems. C1 NOAA, NWS, Ohio River Forecast Ctr, Wilmington, OH 45177 USA. NOAA, Great Lakes Environm Res Lab, Ann Arbor, MI 48105 USA. RP Lee, DH (reprint author), NOAA, NWS, Ohio River Forecast Ctr, 1901 S State St,Rt 134, Wilmington, OH 45177 USA. NR 15 TC 5 Z9 5 U1 1 U2 3 PU ASCE-AMER SOC CIVIL ENGINEERS PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2398 USA SN 0733-9496 J9 J WATER RES PL-ASCE JI J. Water Resour. Plan. Manage.-ASCE PD JUL-AUG PY 1999 VL 125 IS 4 BP 186 EP 193 DI 10.1061/(ASCE)0733-9496(1999)125:4(186) PG 8 WC Engineering, Civil; Water Resources SC Engineering; Water Resources GA 211LB UT WOS:000081161600002 ER PT J AU Dutton, PH Bowen, BW Owens, DW Barragan, A Davis, SK AF Dutton, PH Bowen, BW Owens, DW Barragan, A Davis, SK TI Global phylogeography of the leatherback turtle (Dermochelys coriacea) SO JOURNAL OF ZOOLOGY LA English DT Review DE leatherback turtles; mitochondrial DNA; phylogeography; natal homing; conservation genetics ID MITOCHONDRIAL-DNA SEQUENCES; CONTROL-REGION SEQUENCES; NEST-SITE SELECTION; POPULATION-STRUCTURE; MARINE TURTLES; GENE FLOW; SEA-TURTLES; NATURAL-POPULATIONS; MOLECULAR PHYLOGENY; CARETTA-CARETTA AB Analyses of mitochondrial (mt) DNA control region sequences from 175 leatherback turtles Dermochelys coriacea from 10 nesting colonies revealed shallow phylogenetic structuring of maternal lineages on a global scale. Eleven haplotypes were observed, and mean estimated sequence divergence, p = 0.00581, is much lower than the deepest nodes reported in global mtDNA surveys of the green turtle Chelonia mydas, loggerhead Caretta caretta, and ridley turtles Lepidochelys spp. The leatherback turtle is the product of an evolutionary trajectory originating at least 100 million years ago, yet the intraspecific phylogeny recorded in mitochondrial lineages may trace back less than 900000 years. The gene genealogy and global distribution of mtDNA haplotypes indicate that leatherbacks may have radiated from a narrow refugium, possibly in the Indian-Pacific during the early Pleistocene glaciation. Analysis of haplotype frequencies revealed that nesting populations are strongly subdivided globally (F(ST) = 0.415), and within ocean basins (F(ST) = 0.203-0.253), despite the leatherback's highly migratory nature. Within the Atlantic significant differences in haplotype frequency distributions and Nm Values <2 are observed in pairwise comparisons between St. Croix (U.S. Virgin Islands) and mainland Caribbean populations, and between Trinidad and the same mainland populations. These findings provisionally support the natal homing hypothesis for leatherback turtles, although several proximal nesting populations were indistinguishable, suggesting recent colonization or less precise natal homing behaviour than documented for other marine turtle species. The evidence of natal homing, manifested on ecological time scales, may be erased in some populations by rapid rookery turnover resulting from climatic fluctuation and the ephemeral nature of nesting habitat on a geological time scale. The evolutionary effective population size (N(e)) is estimated from mtDNA data to be between 45 000 and 60 000, a value that exceeds current global census estimates of 26 000 to 43 000 adult females. C1 NOAA, NMFS, SW Fisheries Sci Ctr, La Jolla, CA 92038 USA. Univ Florida, Dept Fisheries & Aquat Sci, Gainesville, FL 32653 USA. Texas A&M Univ, Dept Biol, College Stn, TX 77843 USA. Univ Nacl Autonoma Mexico, Lab Tortugas Marinas, Dept Biol, Fac Ciencias, Mexico City 04510, DF, Mexico. Texas A&M Univ, Dept Anim Sci, College Stn, TX 77843 USA. RP Dutton, PH (reprint author), NOAA, NMFS, SW Fisheries Sci Ctr, POB 271, La Jolla, CA 92038 USA. EM peterd@caliban.ucsd.edu NR 116 TC 86 Z9 93 U1 5 U2 50 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 0952-8369 J9 J ZOOL JI J. Zool. PD JUL PY 1999 VL 248 BP 397 EP 409 PN 3 PG 13 WC Zoology SC Zoology GA 221TK UT WOS:000081742300011 ER PT J AU Kerfoot, WC Robbins, JA Weider, LJ AF Kerfoot, WC Robbins, JA Weider, LJ TI A new approach to historical reconstruction: Combining descriptive and experimental paleolimnology SO LIMNOLOGY AND OCEANOGRAPHY LA English DT Article ID NORTH-AMERICAN BOSMINIDAE; KEWEENAW WATERWAY; ICE ALGAE; SEDIMENTS; ACCUMULATION; PREDATION; ECOSYSTEM; TOXICITY; MICHIGAN; SILICA AB Here we introduce a combined experimental and descriptive approach (termed resurrection ecology) to reconstructing historical perturbations, pointing out how direct tests with sediments and hatched resting eggs complement the traditional descriptive calculation of microfossil fluxes. In the Keweenaw Waterway, a freshwater estuary off Lake Superior, turn-of-the-century copper mining impacted the resident biota. Remain fluxes document that diatom, rhizopod, and Bosmina production all declined during stamp sand discharges but recovered rapidly after World War II, moving above background levels due to developing eutrophication. In addition to biogenic silica, we discovered that bromine flux holds promise as an indicator of diatom production and confirmed that this element is present in several genera. Fluxes of Daphnia resting eggs also increased dramatically since the 1940s, dominated by a hybrid apparently produced from crosses between offshore and interior Waterway species, after channeling promoted greater mixing of water masses. Toxicity studies with sediments and Daphnia clones directly tested recovery of environments after cessation of mining activities. The studies document that increased concentrations and fluxes of copper in the Waterway during mining discharges were toxic to invertebrates. Once stamp sand discharges ceased,the biota recovered rapidly due to a combination of decreased copper cycling and organic complexation. Although sedimentation has returned to near-background conditions and surficial sediments in much of Portage Lake are no longer toxic, eutrophication and faunal exchange with Lake superior make it unlikely that the original zooplankton community composition will return to the Waterway system. C1 Michigan Technol Univ, Lake Super Ecosyst Res Ctr, Houghton, MI 49931 USA. Michigan Technol Univ, Dept Biol Sci, Houghton, MI 49931 USA. NOAA, Great Lakes Environm Res Lab, Ann Arbor, MI 48105 USA. Max Planck Inst Limnol, D-24302 Plon, Germany. RP Kerfoot, WC (reprint author), Michigan Technol Univ, Lake Super Ecosyst Res Ctr, Houghton, MI 49931 USA. NR 55 TC 85 Z9 87 U1 3 U2 37 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 1999 VL 44 IS 5 BP 1232 EP 1247 PG 16 WC Limnology; Oceanography SC Marine & Freshwater Biology; Oceanography GA 219ZN UT WOS:000081639000005 ER PT J AU LeDuc, RG Perrin, WF Dizon, AE AF LeDuc, RG Perrin, WF Dizon, AE TI Phylogenetic relationships among the delphinid cetaceans based on full cytochrome B sequences SO MARINE MAMMAL SCIENCE LA English DT Article DE systematics; delphinid; mitochondrial DNA; evolution; cytochrome b ID MITOCHONDRIAL-DNA; MAXIMUM-LIKELIHOOD; SPECIES TREES; GENE TREES; DOLPHINS; EVOLUTION; WHALES; RECONSTRUCTION; SYSTEMATICS; REVISION AB Complete cytochrome b gene sequences from all bur one species of delphinid plus four outgroups were analyzed using parsimony, maximum likelihood, and neighbor-joining methods. The results indicate the need for systematic revision of the family; a provisional classification is presented and compared to previous studies. Among the suggested revisions are removal of Orcinus from the Globicephalinae, placement of Grampus within the Globicephalinae, removal of all Lagenorhynchus spp. from the Delphininae, and placement of Sousa in the Delphininae. The genus Lagenorhynchus is found to be polyphyletic. L. albirostris (type species for the genus) and L, acutus are. not closely related to each other or to nominal congeners. L. acutus is therefore assigned to the genus Leucopleurus. The remaining four Lagenorhynchus species are closely related ro Lissodelphis and Cephalorhynchus and are placed in the genus Sagmatias. These three genera constitute the revised Lissodelphininae. Within the Delphininae, a well-supported clade includes the two species of Delphinus, Stenella clymene, S, frontalis, S. coeruleoalba, and the aduncus form of Tursiops truncatus. Accepting the monophyly of this group renders the genera Stenella and Tursiops polyphyletic. Apart from this finding, phylogenetic resolution within the Delphininae was poor, so comprehensive taxonomic revision of this group awaits further study. C1 SW Fisheries Sci Ctr, La Jolla, CA 92038 USA. RP LeDuc, RG (reprint author), SW Fisheries Sci Ctr, POB 271, La Jolla, CA 92038 USA. NR 89 TC 190 Z9 243 U1 5 U2 25 PU SOC MARINE MAMMALOGY PI LAWRENCE PA 1041 NEW HAMPSHIRE ST, LAWRENCE, KS 66044 USA SN 0824-0469 J9 MAR MAMMAL SCI JI Mar. Mamm. Sci. PD JUL PY 1999 VL 15 IS 3 BP 619 EP 648 DI 10.1111/j.1748-7692.1999.tb00833.x PG 30 WC Marine & Freshwater Biology; Zoology SC Marine & Freshwater Biology; Zoology GA 206EE UT WOS:000080863700001 ER PT J AU Eberhardt, LL Garrott, RA Becker, BL AF Eberhardt, LL Garrott, RA Becker, BL TI Using trend indices for endangered species SO MARINE MAMMAL SCIENCE LA English DT Article DE auxiliary variables; beach counts; bootstrapping; Hawaiian monk seals; grizzly bears; manatees; transformations; trend indices ID YELLOWSTONE GRIZZLY BEAR; POPULATION-DYNAMICS; CONSERVATION; REGRESSION; POLICIES; SURVIVAL AB Initial appraisals of the status of endangered large-mammal populations may have to depend on indices of population trend. Such indices may possibly be improved by using auxiliary variables. Various models were studied for populations of the Florida manatee (Trichechus manatus latirostris), Yellowstone grizzly bear (Ursus arctos horribilis), and Hawaiian monk seal (Monachus schauinslandi). Several criteria for checking validity of the fitted models were considered, and the simple R-2 criterion appears to provide useful comparisons. Multiple regression models overestimated the rate of change of the East Coast manatee population as determined from three other sources (a covariance model, a non-linear model, and the rate estimated from reproductive and survival data). A multiple regression model for grizzly bears using three auxiliary variables exhibited a fairly high R-2 (0.84)and appeared to provide a better fit than did a non-linear model. A beach count index for Hawaiian monk seals seemed to be unreliable for year-to-year comparisons in contrast to total population counts and estimates from a capture-recapture method. The use of auxiliary variables for checking and improving trend index data appears feasible and well worthwhile. C1 Montana State Univ, Dept Biol, Bozeman, MT 59717 USA. NOAA, Natl Marine Fisheries Serv, Honolulu, HI 96822 USA. RP Eberhardt, LL (reprint author), 2528 W Klamath Ave, Kennewick, WA 99336 USA. NR 32 TC 14 Z9 14 U1 1 U2 4 PU SOC MARINE MAMMALOGY PI LAWRENCE PA 1041 NEW HAMPSHIRE ST, LAWRENCE, KS 66044 USA SN 0824-0469 J9 MAR MAMMAL SCI JI Mar. Mamm. Sci. PD JUL PY 1999 VL 15 IS 3 BP 766 EP 785 DI 10.1111/j.1748-7692.1999.tb00842.x PG 20 WC Marine & Freshwater Biology; Zoology SC Marine & Freshwater Biology; Zoology GA 206EE UT WOS:000080863700010 ER PT J AU Craig, MP Ragen, TJ AF Craig, MP Ragen, TJ TI Body size, survival, and decline of juvenile Hawaiian monk seals, Monachus schauinslandi SO MARINE MAMMAL SCIENCE LA English DT Article DE Hawaiian monk seal; Monachus schauinslandii; demography; conservation biology ID MULTIVARIATE-ANALYSIS; VARIANCE; MORTALITY; BIOLOGY; ECOLOGY; POWER; MASS AB In the mid 1980s half of the entire Hawaiian monk seal species was located at French Frigate Shoals, and this colony may have reached environmental carrying capacity. Since 1989 this colony has declined by 55%, primarily from poor juvenile survival. Only 8%-25% of weaned pups have survived to age 2 during this period, compared to at least 80% between 1984 and 1987. We characterize (1) this drop in survival, (2) a strong, but variable, correlation between survival and size at weaning, (3) interisland differences in size from weaning to age 2 in 1991 through 1993, and (4) decadal-scale changes in mean measures of size at weaning. We. compare observations at French Frigate Shoals with the colony at Laysan Island where abundance is well below historical levels and was therefore expected to be below carrying capacity. At Laysan Island juvenile survival has also been poor (30%-70%), and the size Of weaned pups has decreased during the past decade; Our hypothesis is that poor survival may be due to reduced prey availability at both sites, but particularly at French Frigate Shoals. Evidence to support this hypothesis includes a large increase in total abundance at French Frigate Shoals; reduced size of weaned pups; decreased survival, emaciation, and slower growth rates of juvenile seals; and declining primary productivity. Regardless of cause, the immediate consequences at French Frigate Shoals and Laysan Island, and for the species overall, will likely be poor recruitment and productivity. Because the decline is still in progress, the ultimate consequences for the species' viability are of great concern in light of its already low abundance. C1 Univ Hawaii, Joint Inst Marine & Atmospher Res, Honolulu, HI 96822 USA. NOAA, Natl Marine Fisheries Serv, Honolulu, HI 96822 USA. RP Craig, MP (reprint author), NOAA, Natl Marine Fisheries Serv, 2570 Dole St, Honolulu, HI 96822 USA. NR 57 TC 59 Z9 64 U1 4 U2 37 PU SOC MARINE MAMMALOGY PI LAWRENCE PA 1041 NEW HAMPSHIRE ST, LAWRENCE, KS 66044 USA SN 0824-0469 J9 MAR MAMMAL SCI JI Mar. Mamm. Sci. PD JUL PY 1999 VL 15 IS 3 BP 786 EP 809 DI 10.1111/j.1748-7692.1999.tb00843.x PG 24 WC Marine & Freshwater Biology; Zoology SC Marine & Freshwater Biology; Zoology GA 206EE UT WOS:000080863700011 ER PT J AU Melin, SR DeLong, RL AF Melin, SR DeLong, RL TI Observations of a Guadalupe fur seal (Arctocephalus townsendi) female and pup at San Miguel Island, California SO MARINE MAMMAL SCIENCE LA English DT Article C1 NOAA, Natl Marine Fisheries Serv, Natl Marine Mammal Lab, Alaska Fisheries Sci Ctr, Seattle, WA 98115 USA. RP Melin, SR (reprint author), NOAA, Natl Marine Fisheries Serv, Natl Marine Mammal Lab, Alaska Fisheries Sci Ctr, 7600 Sand Point Way NE,Bldg 4, Seattle, WA 98115 USA. NR 14 TC 5 Z9 5 U1 1 U2 10 PU SOC MARINE MAMMALOGY PI LAWRENCE PA 1041 NEW HAMPSHIRE ST, LAWRENCE, KS 66044 USA SN 0824-0469 J9 MAR MAMMAL SCI JI Mar. Mamm. Sci. PD JUL PY 1999 VL 15 IS 3 BP 885 EP 888 DI 10.1111/j.1748-7692.1999.tb00854.x PG 4 WC Marine & Freshwater Biology; Zoology SC Marine & Freshwater Biology; Zoology GA 206EE UT WOS:000080863700022 ER PT J AU Irvine, GV Mann, DH Short, JW AF Irvine, GV Mann, DH Short, JW TI Multi-year persistence of oil mousse on high energy beaches distant from the Exxon Valdez spill origin SO MARINE POLLUTION BULLETIN LA English DT Article ID FATE; TRANSPORT; SEDIMENTS AB For at least 5 yr after the Exxon Valdez spill, relatively unweathered oil mousse has persisted on the exposed rocky shores of Shelikof Strait 500 km from Prince William Sound, Alaska. Previously it was thought that oil would be rapidly removed from such geomorphic settings by wave action. Oil mousse persists at sites in Katmai National Park and Preserve (NP&P) where it was stranded high in the intertidal zone under a lag of large boulders, These boulders armor the beach, preventing waves from disturbing the substrate and its included oil. Weathering of this stranded mousse has been slight mousse sampled in 1989, 1992 and 1994 show negligible changes in polynuclear aromatic hydrocarbons compared to 11-day old Exxon Valdez crude. The preservation of this oil is due to its transport as mousse bob whose interiors largely escape weathering, followed by its sheltering in the interstices of boulder-armored beaches. The transport of mousse may allow for the long distance dispersal of less weathered, and hence still toxic oil. Our findings suggest that the low ecological sensitivity ratings previously applied to exposed, rocky shorelines need to be modified. The biological threat posed by oil stranded on the Katmai NP&P coast probably is slight because of its small amount and sequestered state. However, it still possesses the ability to be chemically toxic and could be released through disturbance of the armoring boulders by unusually high wave events. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Natl Pk Serv, Alaska Reg Off, Anchorage, AK 99503 USA. Univ Alaska, Inst Arctic Biol, Fairbanks, AK 99775 USA. Natl Marine Fisheries Serv, NOAA, Auke Bay Fisheries Lab, Juneau, AK 99801 USA. RP US Geol Survey, Alaska Biol Sci Ctr, 1011 E Tudor Rd, Anchorage, AK 99503 USA. NR 41 TC 25 Z9 27 U1 1 U2 9 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0025-326X EI 1879-3363 J9 MAR POLLUT BULL JI Mar. Pollut. Bull. PD JUL PY 1999 VL 38 IS 7 BP 572 EP 584 DI 10.1016/S0025-326X(98)00115-5 PG 13 WC Environmental Sciences; Marine & Freshwater Biology SC Environmental Sciences & Ecology; Marine & Freshwater Biology GA 229MK UT WOS:000082198200016 ER PT J AU Jones, RW DeMaria, M AF Jones, RW DeMaria, M TI Further studies of the optimization of a hurricane track prediction model using the adjoint equations SO MONTHLY WEATHER REVIEW LA English DT Article ID CONTINUOUS ASSIMILATION; FORECAST MODEL AB The method of model fitting, or adjoint method, is applied to a barotropic hurricane track forecast model described by DeMaria and Jones using a large sample of forecast cases. The sample includes ail Atlantic tropical cyclones that reached hurricane intensity during the 1989-93 hurricane seasons (141 72-h forecasts of 17 storms). The cases considered by DeMaria and Jones are a subset of the present sample. Model-fitting calculations using strong, weak, strong followed by weak, or weak followed by strong model constraints are discussed for data assimilation period, varying from 6 to 72 h. Generally, the best track forecasts occur for shorter assimilation periods and for weak constraints, although only the 12-h assimilation with the weak constraint has less track error than the control forecast without assimilation, and only for the 12-h forecast. The principle reason for this lack of improvement is that the fit of the model to the observed track is god at the middle of the assimilation period, bur not very good at the end where the forecast begins. When a future track position at 6 h is included in the assimilation, in order to improve the track Fit at the synoptic data time, the resulting track errors average about 10% smaller than the control forecast. The control forecast may also be improved in the same way. In that case, the best assimilation forecasts have 2.5% smaller track errors than the modified control forecasts. C1 NOAA, Atlantic Oceanog & Meteorol Lab, Hurricane Res Div, Miami, FL 33149 USA. Trop Predict Ctr, Miami, FL USA. RP Jones, RW (reprint author), NOAA, Atlantic Oceanog & Meteorol Lab, Hurricane Res Div, 4301 Rickenbacker Causeway, Miami, FL 33149 USA. RI DeMaria, Mark/F-5583-2010 NR 11 TC 1 Z9 1 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 JUL PY 1999 VL 127 IS 7 BP 1586 EP 1598 DI 10.1175/1520-0493(1999)127<1586:FSOTOO>2.0.CO;2 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 221VZ UT WOS:000081748900011 ER PT J AU Grivet-Talocia, S Einaudi, F Clark, WL Dennett, RD Nastrom, GD VanZandt, TE AF Grivet-Talocia, S Einaudi, F Clark, WL Dennett, RD Nastrom, GD VanZandt, TE TI A 4-yr climatology of pressure disturbances using a barometer network in central Illinois SO MONTHLY WEATHER REVIEW LA English DT Article ID DOPPLER-SPREAD PARAMETERIZATION; MESOSCALE WAVE DISTURBANCES; ATMOSPHERIC GRAVITY-WAVES; NUMERICAL SPECTRAL MODEL; 15 DECEMBER 1987; MIDDLE ATMOSPHERE; LOWER STRATOSPHERE; EQUATORIAL OSCILLATIONS; MOMENTUM DEPOSITION; CONVECTIVE STORMS AB This paper presents a climatology of coherent disturbances detected during 1991-95 by a network of barometers with a diameter of about 50 km located in a very Aat terrain centered on the Flatland Atmospheric Observatory in east-central Illinois. An automatic, wavelet-based adaptive filter is used to extract the waveforms of all disturbance events with amplitudes larger than a frequency-dependent threshold. The extracted events cover characteristic temporal scales from about 30 min to 6 h. that is, the range that includes mesoscale disturbances that affect the weather and the forecasts. The analysis resulted in two classes of events. One class, called coherent events, or CEs, consists of disturbances that propagated coherently through the barograph network and for which the phase propagation velocity, dominant period, and horizontal wavelength could be estimated with good accuracy. The propagation direction of 97% of the CEs were between 0 degrees and 180 degrees (i.e., had an eastward component) and the speeds of 96% were between 10 and 50 m s(-1) with a mode at 25-30 m s(-1). The other class, called incoherent events, or IEs, consists of disturbances that had significant amplitudes but that did not propagate coherently across the network, so that the propagation velocity could not be estimated. This class consists of localized disturbances and wave packets with short periods and/or wavelengths, or with pressure signatures that were too different at the network stations. The extracted events are attributed to gravity waves. wave packers, gravity currents, pressure jumps, solitary waves, bores, etc. The rate of occurrence of events had a strong seasonal dependence, with a maximum in fall and winter and a minimum in summer. The CEs occurred about 20%-21% of the total time in fall and winter and 12% in summer, while all events occurred 34% in both fail and winter and 23% in summer. The seasonal dependence of events confirms the strong relation of these disturbances to the baroclinicity of the atmosphere. Concurrent vertical velocity fluctuations observed by the 50-MHz radar at the Flatland Atmospheric Observatory showed that many of the large-amplitude events extended up to at least 7 km. the highest altitude reliably observed by the radar. C1 NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. NOAA, Aeron Lab, Boulder, CO 80303 USA. St Cloud State Univ, Dept Earth Sci, St Cloud, MN 56301 USA. RP Grivet-Talocia, S (reprint author), Politecn Torino, C Duca Abruzzi 24, I-10129 Turin, Italy. EM grivet@polito.it RI Grivet-Talocia, Stefano/M-1480-2015 OI Grivet-Talocia, Stefano/0000-0002-5463-3810 NR 56 TC 13 Z9 13 U1 1 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 JUL PY 1999 VL 127 IS 7 BP 1613 EP 1629 DI 10.1175/1520-0493(1999)127<1613:AYCOPD>2.0.CO;2 PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 221VZ UT WOS:000081748900013 ER PT J AU Segal, M Anderson, C Arritt, RW Rabin, RM Martin, DW AF Segal, M Anderson, C Arritt, RW Rabin, RM Martin, DW TI Some observations of the clearing of cumulus clouds downwind from snow-covered areas SO MONTHLY WEATHER REVIEW LA English DT Article ID MESOSCALE CIRCULATIONS; BREEZE AB Satellite images that illustrate the clearing of cumulus clouds downwind from snow-covered areas are presented. The cloud clearing resembles that occasionally observed with lakes during warm advection, supporting the suggestion that the thermal forcing associated with a uniform snow-covered area is comparable to that of a coldwater lake of similar size. Analysis of snow cover patterns in the central United States suggests that the climatological probability for situations conducive to the cloud clearing is at most once per month. C1 Iowa State Univ Sci & Technol, Dept Agron, Ames, IA 50011 USA. Univ Wisconsin, Ctr Space Sci & Engn, Madison, WI USA. NOAA, Natl Severe Storms Lab, Cooperat Inst Meteorol Satellite Studies, Norman, OK 73069 USA. RP Segal, M (reprint author), Iowa State Univ Sci & Technol, Dept Agron, Ames, IA 50011 USA. NR 12 TC 3 Z9 3 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0027-0644 J9 MON WEATHER REV JI Mon. Weather Rev. PD JUL PY 1999 VL 127 IS 7 BP 1687 EP 1692 DI 10.1175/1520-0493(1999)127<1687:SOOTCO>2.0.CO;2 PG 6 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 221VZ UT WOS:000081748900019 ER PT J AU Trapp, RJ AF Trapp, RJ TI Observations of nontornadic low-level mesocyclones and attendant tornadogenesis failure during VORTEX SO MONTHLY WEATHER REVIEW LA English DT Article; Proceedings Paper CT 28th Conference on Radar Meteorology CY SEP 07-12, 1997 CL AUSTIN, TEXAS SP Amer Meteorol Soc ID SIMULATED CONVECTIVE STORMS; DOPPLER RADAR; DYNAMICS; ROTATION; THUNDERSTORMS; TORNADOES; ORIGINS; MODEL AB Three storms intercepted during the Verification of the Origins of Rotation in Tornadoes Experiment generated a moderate-to-strong mesocyclone within the lowest several hundred meters above the ground and qualitatively appeared capable of tornadogenesis, yet did ndt produce a tornado. Such novel observations of what is considered "tornadogenesis failure" are documented and used to show the insufficiency of a low-level mesocyclone for tornadogenesis. Possible modes of failure are discussed. C1 NOAA, Natl Severe Storms Lab, Norman, OK 73069 USA. Univ Oklahoma, Cooperat Inst Mesoscale Meteorol Studies, Norman, OK 73019 USA. RP Trapp, RJ (reprint author), NOAA, Natl Severe Storms Lab, 1313 Halley Circle, Norman, OK 73069 USA. NR 50 TC 54 Z9 56 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 JUL PY 1999 VL 127 IS 7 BP 1693 EP 1705 DI 10.1175/1520-0493(1999)127<1693:OONLLM>2.0.CO;2 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 221VZ UT WOS:000081748900020 ER PT J AU Powell, MD Houston, SH AF Powell, MD Houston, SH TI A multiscale numerical study of hurricane Andrew (1992). Part I: explicit simulation and verification - Comments SO MONTHLY WEATHER REVIEW LA English DT Letter ID SURFACE WIND FIELDS; TROPICAL CYCLONES; SOUTH FLORIDA; SEA-SURFACE; LANDFALL; COEFFICIENTS; MODEL C1 NOAA, Atlantic Oceanog & Meteorol Lab, Hurricane Res Div, Miami, FL 33149 USA. RP Powell, MD (reprint author), NOAA, Atlantic Oceanog & Meteorol Lab, Hurricane Res Div, 4301 Rickenbacker Cswy, Miami, FL 33149 USA. RI Powell, Mark/I-4963-2013 OI Powell, Mark/0000-0002-4890-8945 NR 29 TC 3 Z9 3 U1 1 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 JUL PY 1999 VL 127 IS 7 BP 1706 EP 1710 DI 10.1175/1520-0493(1999)127<1706:COAMNS>2.0.CO;2 PG 5 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 221VZ UT WOS:000081748900021 ER PT J AU Josell, D Carter, WC Bonevich, JE AF Josell, D Carter, WC Bonevich, JE TI Stability of multilayer structures: Capillary effects SO NANOSTRUCTURED MATERIALS LA English DT Article; Proceedings Paper CT 4th International Conference on Nanostructured Materials (NANO 98) CY JUN 14-19, 1998 CL STOCKHOLM, SWEDEN SP Royal Inst Technol, Sweden, Swedish Consortium Clusters & Ultrafine Particles, Sweden, Royal Inst Technol, Brinell Ctr, Sweden, European Consortium Nanophase Mat, Switzerland, Acta Met Inc, USA, Alps Elect Co, Japan, Canon Ctr City, Sweden, Carl Tryggers Stiftelse, Sweden, Elsevier Sci Inc, Switzerland, Finnair, Finland, Off Naval Res ONR, USA, European Res Off US Army, USARDSD-UK, Swedish Nat Sci Res Council, NFR, Sweden, Swedish Res Council Engn Sci, TFR, Sweden, Swedish Nat Board Ind & Tech Dev (NUTEK), Swedish Royal Acad Sci, Nobel Comm Phys, Sweden, Swedish Royal Acad Sci, Nobel comm Chem, Sweden ID ZERO CREEP EXPERIMENTS; INTERFACIAL-TENSION; THERMAL-DIFFUSION; THIN-FILM AB The long term stability of multilayer materials composed of nonreactive, immiscible materials is related to the equilibrium shapes of the individual grains within the layers. These shapes are determined by the free energies and locations of the interfaces within the multilayer. We link the results of zero creep experiments with measured grain boundary groove angles to understand experimental observations of multilayer stability. (C) 1999 Acta Metallurgica Inc. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Josell, D (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RI Carter, W/K-2406-2012 NR 9 TC 24 Z9 25 U1 1 U2 10 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0965-9773 J9 NANOSTRUCT MATER JI Nanostruct. Mater. PD JUL PY 1999 VL 12 IS 1-4 SI SI BP 387 EP 390 DI 10.1016/S0965-9773(99)00141-5 PN A PG 4 WC Materials Science, Multidisciplinary SC Materials Science GA 224RM UT WOS:000081912100088 ER PT J AU Josell, D van Heerden, D Shechtman, D Read, D AF Josell, D van Heerden, D Shechtman, D Read, D TI Mechanical properties of multilayer materials SO NANOSTRUCTURED MATERIALS LA English DT Article; Proceedings Paper CT 4th International Conference on Nanostructured Materials (NANO 98) CY JUN 14-19, 1998 CL STOCKHOLM, SWEDEN SP Royal Inst Technol, Sweden, Swedish Consortium Clusters & Ultrafine Particles, Sweden, Royal Inst Technol, Brinell Ctr, Sweden, European Consortium Nanophase Mat, Switzerland, Acta Met Inc, USA, Alps Elect Co, Japan, Canon Ctr City, Sweden, Carl Tryggers Stiftelse, Sweden, Elsevier Sci Inc, Switzerland, Finnair, Finland, Off Naval Res ONR, USA, European Res Off US Army, USARDSD-UK, Swedish Nat Sci Res Council, NFR, Sweden, Swedish Res Council Engn Sci, TFR, Sweden, Swedish Nat Board Ind & Tech Dev (NUTEK), Swedish Royal Acad Sci, Nobel Comm Phys, Sweden, Swedish Royal Acad Sci, Nobel comm Chem, Sweden ID FCC TITANIUM AB We conducted tensile rests of free standing Al/Ti multilayer thin films in order to determine the dependence of yield stress on layer thickness. The multilayers studied were composed of fcc and hcp Ti layers. The Al layers were approximately twice the thickness of the Ti layers. Because a controversy exists concerning the crystalline structure of Ti in Al/Ti multilayers, we also present microstructural results. (C) 1999 Acta Metallurgica Inc. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Johns Hopkins Univ, Baltimore, MD USA. Technion Israel Inst Technol, Haifa, Israel. Natl Inst Stand & Technol, Boulder, CO USA. RP Josell, D (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NR 7 TC 3 Z9 3 U1 0 U2 5 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0965-9773 J9 NANOSTRUCT MATER JI Nanostruct. Mater. PD JUL PY 1999 VL 12 IS 1-4 SI SI BP 405 EP 408 DI 10.1016/S0965-9773(99)00145-2 PN A PG 4 WC Materials Science, Multidisciplinary SC Materials Science GA 224RM UT WOS:000081912100092 ER PT J AU Merzbacher, CI Barker, JG Long, JW Rolison, DR AF Merzbacher, CI Barker, JG Long, JW Rolison, DR TI The morphology of nanoscale deposits of ruthenium oxide in silica aerogels SO NANOSTRUCTURED MATERIALS LA English DT Article; Proceedings Paper CT 4th International Conference on Nanostructured Materials (NANO 98) CY JUN 14-19, 1998 CL STOCKHOLM, SWEDEN SP Royal Inst Technol, Sweden, Swedish Consortium Clusters & Ultrafine Particles, Sweden, Royal Inst Technol, Brinell Ctr, Sweden, European Consortium Nanophase Mat, Switzerland, Acta Met Inc, USA, Alps Elect Co, Japan, Canon Ctr City, Sweden, Carl Tryggers Stiftelse, Sweden, Elsevier Sci Inc, Switzerland, Finnair, Finland, Off Naval Res ONR, USA, European Res Off US Army, USARDSD-UK, Swedish Nat Sci Res Council, NFR, Sweden, Swedish Res Council Engn Sci, TFR, Sweden, Swedish Nat Board Ind & Tech Dev (NUTEK), Swedish Royal Acad Sci, Nobel Comm Phys, Sweden, Swedish Royal Acad Sci, Nobel comm Chem, Sweden AB Ruthenium oxide was deposited an the internal surfaces of silica aerogel by solution impregnation of a Ru(III)tris-acetylacetonate solution followed by reduction and oxidation. The structure of the Ru phase was determined by contrast-matching SANS, which allows independent collection of scattered intensity from SiO2 and Ru oxide components of composite samples. The structure of the Ru oxide deposit depends strongly on the oxidation temperature and very little on the reduction temperature. The Ru oxide forms particles, rather than a conformal layer, which coarsen from a few nanometers after oxidation at room temperature to several tens of nm after oxidation at 250 degrees C. (C) 1999 Acta Metallurgica Inc. C1 USN, Res Lab, Div Opt Sci, Washington, DC 20375 USA. NIST, Ctr Neutron Res, Gaithersburg, MD 20899 USA. USN, Res Lab, Div Chem, Washington, DC 20375 USA. RP Merzbacher, CI (reprint author), USN, Res Lab, Div Opt Sci, Washington, DC 20375 USA. NR 5 TC 11 Z9 11 U1 0 U2 3 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0965-9773 J9 NANOSTRUCT MATER JI Nanostruct. Mater. PD JUL PY 1999 VL 12 IS 1-4 SI SI BP 551 EP 554 DI 10.1016/S0965-9773(99)00181-6 PN A PG 4 WC Materials Science, Multidisciplinary SC Materials Science GA 224RM UT WOS:000081912100128 ER PT J AU Sponberg, K AF Sponberg, K TI Weathering a storm of global statistics SO NATURE LA English DT Letter C1 NOAA, Off Global Programs, Silver Spring, MD 20910 USA. RP Sponberg, K (reprint author), NOAA, Off Global Programs, 1100 Wayne Ave,Suite 1210, Silver Spring, MD 20910 USA. NR 5 TC 2 Z9 2 U1 0 U2 0 PU MACMILLAN MAGAZINES LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD JUL 1 PY 1999 VL 400 IS 6739 BP 13 EP 13 DI 10.1038/21758 PG 1 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 213DA UT WOS:000081255700018 ER PT J AU Sung, LP Mulholland, GW Germer, TA AF Sung, LP Mulholland, GW Germer, TA TI Polarized light-scattering measurements of dielectric spheres upon a silicon surface SO OPTICS LETTERS LA English DT Article ID MUELLER MATRIX; PLANE; RAYLEIGH AB The polarization of light scattered into directions out of the plane of incidence by polystyrene latex spheres upon a silicon substrate was measured for p-polarized incident light. The experimental data show good agreement with theoretical predictions for three sizes of spheres. These results demonstrate that the polarization of light scattered by particles can be used to determine the size of particulate contaminants on silicon wafers. Theoretical models, based on successive degrees of approximation. indicate that the mean distance of a particle from the surface is the primary determinant of the scattered light polarization for small out-of-plane scattering angles. OCIS codes: 290.5820, 290.5850, 260.5430, 120.4630. C1 NIST, Gaithersburg, MD 20899 USA. Univ Maryland, College Pk, MD 20742 USA. RP Sung, LP (reprint author), NIST, Gaithersburg, MD 20899 USA. NR 13 TC 24 Z9 24 U1 0 U2 3 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 0146-9592 J9 OPT LETT JI Opt. Lett. PD JUL 1 PY 1999 VL 24 IS 13 BP 866 EP 868 DI 10.1364/OL.24.000866 PG 3 WC Optics SC Optics GA 212PP UT WOS:000081225700002 PM 18073878 ER PT J AU Graczyk, TK Fayer, R Lewis, EJ Trout, JM Farley, CA AF Graczyk, TK Fayer, R Lewis, EJ Trout, JM Farley, CA TI Cryptosporidium oocysts in Bent mussels (Ischadium recurvum) in the Chesapeake Bay SO PARASITOLOGY RESEARCH LA English DT Article ID CRASSOSTREA-VIRGINICA; PARVUM AB Filter-feeding molluscan shellfish can concentrate environmentally derived waterborne pathogens of humans, which can be utilized in the sanitary assessment of water quality. In the present study, oocysts of Cryptosporidium were detected in Bent mussels (Ischadium recurvum) at two Chesapeake Bay sites from which C. parvum-contaminated oysters had previously been collected. Spiking of Cryptosporidium-free blue mussel (Mytilus edulis) tissue with C. parvum oocysts showed a 51.1% recovery rate of oocysts, giving an oocyst detection limit of 19 oocysts/0.7 mi of mussel tissue homogenate. The results indicate that Bent mussels, which are common throughout the Chesapeake Bay region, may prove to be useful as biological indicators of water contamination with Cryptosporidium oocysts. C1 Johns Hopkins Univ, Sch Hyg & Publ Hlth, Dept Mol Microbiol & Immunol, Baltimore, MD 21205 USA. ARS, Immun & Dis Resistance Lab, Inst Livestock & Poultry Sci, USDA, Beltsville, MD 20705 USA. Natl Marine Fisheries Serv, Cooperat Oxford Lab, NOAA, US Dept Commerce, Oxford, MD 21654 USA. RP Graczyk, TK (reprint author), Johns Hopkins Univ, Sch Hyg & Publ Hlth, Dept Mol Microbiol & Immunol, 615 N Wolfe St, Baltimore, MD 21205 USA. NR 15 TC 59 Z9 62 U1 0 U2 2 PU SPRINGER VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0044-3255 J9 PARASITOL RES JI Parasitol. Res. PD JUL PY 1999 VL 85 IS 7 BP 518 EP 521 DI 10.1007/s004360050590 PG 4 WC Parasitology SC Parasitology GA 200UE UT WOS:000080557800002 PM 10382600 ER PT J AU Cockayne, E Mihalkovic, M AF Cockayne, E Mihalkovic, M TI Stable quasicrystalline sphere packing SO PHILOSOPHICAL MAGAZINE LETTERS LA English DT Article ID TRANSLATIONAL SYMMETRY; TILINGS AB Wills (1990, J. Phys., Paris, 51, 1061) found a method relating certain decagonal disc packings to decagonal sphere packings with high packing fractions. Applying this technique to the decagonal rectangle-triangle tiling generated by inflation, we obtain a sphere packing with decagonal symmetry and a packing fraction greater than 0.6953. This is the densest known stable quasicrystalline sphere packing. C1 Slovak Acad Sci, Inst Phys, SK-84228 Bratislava, Slovakia. NIST, Div Ceram, Gaithersburg, MD 20899 USA. Tech Univ Chemnitz, Inst Phys, D-09107 Chemnitz, Germany. RP Cockayne, E (reprint author), NIST, Div Ceram, 100 Bur Dr Stop 8520, Gaithersburg, MD 20899 USA. NR 22 TC 7 Z9 7 U1 0 U2 1 PU TAYLOR & FRANCIS LTD PI LONDON PA ONE GUNPOWDER SQUARE, LONDON EC4A 3DE, ENGLAND SN 0950-0839 J9 PHIL MAG LETT JI Philos. Mag. Lett. PD JUL PY 1999 VL 79 IS 7 BP 441 EP 448 DI 10.1080/095008399177066 PG 8 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Physics, Applied; Physics, Condensed Matter SC Materials Science; Metallurgy & Metallurgical Engineering; Physics GA 214DX UT WOS:000081313300005 ER PT J AU Bohn, JL Julienne, PS AF Bohn, JL Julienne, PS TI Semianalytic theory of laser-assisted resonant cold collisions SO PHYSICAL REVIEW A LA English DT Article ID SCATTERING LENGTH; ULTRACOLD MOLECULES; SLOW COLLISIONS; IDENTICAL ATOMS; LIGHT; PHOTOASSOCIATION; FIELD; SPECTROSCOPY; LITHIUM AB A general formalism is derived for analytically representing the scattering properties of ultracold atoms subject to one or more resonant photoassociation lasers. The resulting formulas cleanly separate laser intensities and detunings from overlap integrals of molecular wave functions. As a consequence. laser-induced energy shifts and line broadenings are given in an explicit form. Ln the case of the initial photoassociation step, these quantities are given more simply in terms of the relevant molecular potential curves and wave functions near the Condon point. [S1050-2947(99)01007-7]. C1 Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. Univ Colorado, Dept Phys, Boulder, CO 80309 USA. NIST, Atom Phys Div, Gaithersburg, MD 20899 USA. RP Bohn, JL (reprint author), Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. RI Julienne, Paul/E-9378-2012 OI Julienne, Paul/0000-0002-5494-1442 NR 41 TC 153 Z9 154 U1 0 U2 6 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 1999 VL 60 IS 1 BP 414 EP 425 DI 10.1103/PhysRevA.60.414 PG 12 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 212ZF UT WOS:000081247000061 ER PT J AU Do, B Cha, J Elliott, DS Smith, SJ AF Do, B Cha, J Elliott, DS Smith, SJ TI Phase-conjugate four-wave mixing with partially coherent laser fields SO PHYSICAL REVIEW A LA English DT Article ID DIFFUSING OPTICAL-FIELDS; SPECTRAL-LINE SHAPE; INCOHERENT-LIGHT; PHOTON-ECHOES; FLUCTUATING PULSES; DEPHASING-TIME; TRANSIENTS; ABSORPTION; EXCITATION; REGIME AB We present results of our experimental investigations of phase-conjugate four-wave mixing in a nearly Doppler-free, collisionless, two-level quantum system with a partially coherent non-Markovian laser field. The two components of the laser field-an intense pump and a weak, time-delayed probe-are derived from a single narrow-band cw laser source on which phase and frequency fluctuations conforming to the phase diffusion model are superimposed. We carry out these measurements using the D-2 transition in an optically pumped diffuse beam of atomic sodium. We vary the pump intensity, laser bandwidth, and temporal delay between the pump and probe, and measure the peak signal strength, the bandwidth, and the asymmetry of the four-wave-mixing spectrum. For comparison with our experimental results of the peak signal strength, we also analyze the same interaction numerically, through direct integration of the optical Bloch equations. The numerical results are in good agreement with the measurements. [S1050-2947(99)00307-8]. C1 Purdue Univ, Dept Phys, W Lafayette, IN 47907 USA. Purdue Univ, Sch Elect & Comp Engn, W Lafayette, IN 47907 USA. Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. Natl Inst Stand & Technol, Boulder, CO 80309 USA. RP Do, B (reprint author), Purdue Univ, Dept Phys, W Lafayette, IN 47907 USA. NR 38 TC 4 Z9 4 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 JUL PY 1999 VL 60 IS 1 BP 508 EP 517 DI 10.1103/PhysRevA.60.508 PG 10 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 212ZF UT WOS:000081247000072 ER PT J AU Kmety, CR Manson, JL Huang, QZ Lynn, JW Erwin, RW Miller, JS Epstein, AJ AF Kmety, CR Manson, JL Huang, QZ Lynn, JW Erwin, RW Miller, JS Epstein, AJ TI Collinear ferromagnetism and spin orientation in the molecule-based magnets M[N(CN)(2)](2) (M = Co,Ni) SO PHYSICAL REVIEW B LA English DT Article ID NEUTRON-DIFFRACTION; CRYSTAL; DENSITY; ORDER; CO; NI AB Zero-held unpolarized neutron powder diffraction has been used to study the low-T magnetic structure and T-dependent crystal structure of M[N(CN)(2)](2) (M = Co,Ni). Both compounds show collinear ferromagnetism with spin orientation along the c axis. The results provide the determination of a complete magnetic structure in the ordered state for a molecule-based magnet. The c lattice parameter exhibits negative thermal expansion, explained by a wine-rack-like deformation. [S0163-1829(99)10225-X]. C1 Ohio State Univ, Dept Phys, Columbus, OH 43210 USA. Univ Utah, Dept Chem, Salt Lake City, UT 84112 USA. NIST, Ctr Neutron Res, Gaithersburg, MD 20899 USA. Univ Maryland, Dept Mat & Nucl Engn, College Pk, MD 20742 USA. RP Kmety, CR (reprint author), Ohio State Univ, Dept Phys, 174 W 18th Ave, Columbus, OH 43210 USA. NR 19 TC 27 Z9 28 U1 1 U2 5 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 JUL 1 PY 1999 VL 60 IS 1 BP 60 EP 63 DI 10.1103/PhysRevB.60.60 PG 4 WC Physics, Condensed Matter SC Physics GA 218KE UT WOS:000081551100016 ER PT J AU Yildirim, T Gehring, PM Neumann, DA Eaton, PE Emrick, T AF Yildirim, T Gehring, PM Neumann, DA Eaton, PE Emrick, T TI Neutron-scattering investigation of molecular reorientations in solid cubane SO PHYSICAL REVIEW B LA English DT Article ID ORIENTATIONAL DISORDER; ROTATIONAL-DYNAMICS; PHASE-TRANSITION; NMR; C60 AB We have studied the reorientations of the cube-shaped molecule cubane (C8H8) in its solid phase using quasielastic neutron-scattering techniques both below and above the molecular orientational phase-transition temperature T-p = 394 K. In the orientationally ordered phase, just below T-p the elastic incoherent structure factor (EISF) extracted from neutron time-of-flight measurements indicates that cubane undergoes rr jumps about the molecular fourfold axis. In the disordered phase we find that the EISF excludes isotropic and free uniaxial rotational motions of the molecule. Instead our data suggest cubane undergoes uncorrelated rr jumps about the fourfold axis (as in the ordered phase) and 2 pi/3 jumps about the threefold axis. [S0163-1829(99)04725-6]. C1 Univ Maryland, College Pk, MD 20742 USA. Natl Inst Stand & Technol, Ctr Neutron Res, Gaithersburg, MD 20899 USA. Univ Chicago, Dept Chem, Chicago, IL 60637 USA. RP Yildirim, T (reprint author), Univ Maryland, College Pk, MD 20742 USA. RI yildirim, taner/A-1290-2009; OI Gehring, Peter/0000-0002-9236-2046 NR 27 TC 28 Z9 29 U1 0 U2 7 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 JUL 1 PY 1999 VL 60 IS 1 BP 314 EP 321 DI 10.1103/PhysRevB.60.314 PG 8 WC Physics, Condensed Matter SC Physics GA 218KE UT WOS:000081551100048 ER PT J AU Ravel, B Bouldin, CE Renevier, H Hodeau, JL Berar, JF AF Ravel, B Bouldin, CE Renevier, H Hodeau, JL Berar, JF TI X-ray-absorption edge separation using diffraction anomalous fine structure SO PHYSICAL REVIEW B LA English DT Article ID SCATTERING-AMPLITUDES; LOCAL-STRUCTURE; SPECTROSCOPY; SPECTRA; DAFS AB When two or more absorption edges in a material are sufficiently close in energy, extended-x-ray-absorption-fine-structure spectroscopy is of limited utility as the usable data range above the lower-energy edge is truncated by the higher-energy edge. Energy or wavelength discriminating detection methods may fail to resolve fluorescence lines which are very close in energy. In this paper we present a solution to this problem using the resolution in momentum transfer of diffraction anomalous fine structure (DAFS) to separate the fine-structure signals from elements with closely spaced fluorescence lines. We demonstrate our technique by isolating the titanium edge signal from DAFS measurements of BaTiO3. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. CNRS, Cristallog Lab, F-38042 Grenoble 09, France. RP Ravel, B (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RI d2am, beamline/I-6445-2015 NR 26 TC 14 Z9 14 U1 0 U2 7 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 JUL 1 PY 1999 VL 60 IS 2 BP 778 EP 785 DI 10.1103/PhysRevB.60.778 PG 8 WC Physics, Condensed Matter SC Physics GA 218QU UT WOS:000081563800015 ER PT J AU Ghosez, P Cockayne, E Waghmare, UV Rabe, KM AF Ghosez, P Cockayne, E Waghmare, UV Rabe, KM TI Lattice dynamics of BaTiO3, PbTiO3, and PbZrO3: A comparative first-principles study SO PHYSICAL REVIEW B LA English DT Article ID INTERATOMIC FORCE-CONSTANTS; FUNCTIONAL PERTURBATION-THEORY; PHASE-TRANSITIONS; FERROELECTRIC INSTABILITY; ANTIFERROELECTRIC PBZRO3; COULOMB INTERACTION; EFFECTIVE CHARGES; BARIUM-TITANATE; ALPHA-QUARTZ; KNBO3 AB The full phonon dispersion relations of lead titanate and lead zirconate in the cubic perovskite structure are computed using first-principles variational density-functional perturbation theory, with nb initio pseudopotentials and a plane-wave basis set. Comparison with the results previously obtained for barium titanate shows that the change of a single constituent (Ba to Pb, Ti to Zr) has profound effects on the character and dispersion of unstable modes, with significant implications for the nature of the phase transitions and the dielectric and piezoelectric responses of the compounds. Examination of the interatomic force constants in real space, obtained by a transformation which correctly treats the long-range dipolar contribution, shows that most are strikingly similar, while it is the differences in a few key interactions which produce the observed changes in the phonon dispersions. These trends suggest the possibility of the transferability of force constants to predict the lattice dynamics of perovskite solid solutions. C1 Yale Univ, Dept Appl Phys, New Haven, CT 06520 USA. RP Ghosez, P (reprint author), Natl Inst Stand & Technol, Div Ceram, Gaithersburg, MD 20899 USA. NR 34 TC 260 Z9 263 U1 15 U2 146 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 JUL 1 PY 1999 VL 60 IS 2 BP 836 EP 843 DI 10.1103/PhysRevB.60.836 PG 8 WC Physics, Condensed Matter SC Physics GA 218QU UT WOS:000081563800022 ER PT J AU Snyder, CR Mopsik, FI AF Snyder, CR Mopsik, FI TI Critical comparison between time- and frequency-domain relaxation functions SO PHYSICAL REVIEW B LA English DT Article ID KOHLRAUSCH-WILLIAMS-WATTS; DIELECTRIC-RELAXATION; HAVRILIAK-NEGAMI; CONSTRAINED DYNAMICS; MODELS AB Considerable work has been performed on providing a theoretical basis for the Kohlrausch-Williams-Watts (KWW) and Havriliak-Negami (HN) relaxation functions. Because of this, several papers have examined the "interconnection" of these two functions. In this paper, we demonstrate that, with achievable instrumental sensitivity, these two functions are distinguishable. We further address the issue of the "universal" limiting power laws and the ability to obtain the exponents associated with them. Finally, the stability and accuracy of our numerical Laplace transform is demonstrated by comparison between functions with known analytical time and frequency solutions, The stability of our algorithm indicates that the method of Alvarez and co-workers is an unnecessary approximation for converting between the rime and frequency domain. [S0163-1829(99)01026-7]. C1 NIST, Elect Applicat Grp, Div Polymer, Gaithersburg, MD 20899 USA. RP Snyder, CR (reprint author), NIST, Elect Applicat Grp, Div Polymer, Gaithersburg, MD 20899 USA. RI Snyder, Chad/B-4957-2008 OI Snyder, Chad/0000-0002-2916-9809 NR 33 TC 12 Z9 12 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 JUL 1 PY 1999 VL 60 IS 2 BP 984 EP 990 DI 10.1103/PhysRevB.60.984 PG 7 WC Physics, Condensed Matter SC Physics GA 218QU UT WOS:000081563800041 ER PT J AU Wakimoto, S Shirane, G Endoh, Y Hirota, K Ueki, S Yamada, K Birgeneau, RJ Kastner, MA Lee, YS Gehring, PM Lee, SH AF Wakimoto, S Shirane, G Endoh, Y Hirota, K Ueki, S Yamada, K Birgeneau, RJ Kastner, MA Lee, YS Gehring, PM Lee, SH TI Observation of incommensurate magnetic correlations at the lower critical concentration for superconductivity in La2-xSrxCuO4 (x=0.05) SO PHYSICAL REVIEW B LA English DT Article ID NEUTRON-SCATTERING; SPIN AB Neutron-scattering experiments have been performed on lightly doped La2-xSrxCuO4 single crystals in both the insulating (x = 0.03,0.04,0.05) and superconducting (x = 0.06) regions. Elastic magnetic peaks are observed at low temperatures in all samples with the maximum peak linewidth occurring at the critical concentration x,= 0.05. Incommensurate peaks are observed only at x = 0.05, the positions of which are rotated by 45 degrees in reciprocal space about (pi,pi) from those observed for x greater than or equal to 0.06 in the superconducting phase. C1 Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. Tohoku Univ, Dept Phys, Sendai, Miyagi 9808578, Japan. MIT, Dept Phys, Cambridge, MA 02139 USA. NIST, Ctr Neutron Res, Gaithersburg, MD 20899 USA. RP Wakimoto, S (reprint author), Brookhaven Natl Lab, Dept Phys, Upton, NY 11973 USA. RI Hirota, Kazuma/C-6797-2008; Yamada, Kazuyoshi/C-2728-2009 NR 13 TC 149 Z9 149 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 JUL 1 PY 1999 VL 60 IS 2 BP R769 EP R772 DI 10.1103/PhysRevB.60.R769 PG 4 WC Physics, Condensed Matter SC Physics GA 218QU UT WOS:000081563800013 ER PT J AU Lapena, AM Glotzer, SC Langer, SA Liu, AJ AF Lapena, AM Glotzer, SC Langer, SA Liu, AJ TI Effect of ordering on spinodal decomposition of liquid-crystal/polymer mixtures SO PHYSICAL REVIEW E LA English DT Article ID PHASE-SEPARATION; POLYMER NETWORKS; CRYSTALS; KINETICS; MONOMERS AB Partially phase-separated liquid-crystal/polymer dispersions display highly fibrillar domain morphologies that are dramatically different from the typical structures found in isotropic mixtures. To explain this, we numerically explore the coupling between phase ordering an phase-separation kinetics in model two-dimensional fluid mixtures phase separating into a nematic phase, rich in liquid crystal, coexisting with an isotropic phase, rich in polymer. We find that phase ordering can lead to fibrillar networks of the minority polymer-rich phase. [S1063-651X(99)51207-5]. C1 Univ Calif Los Angeles, Dept Chem & Biochem, Los Angeles, CA 90095 USA. Natl Inst Stand & Technol, Div Polymers, Gaithersburg, MD 20899 USA. Natl Inst Stand & Technol, Ctr Theoret & Computat Mat Sci, Gaithersburg, MD 20899 USA. Natl Inst Stand & Technol, Informat Technol Lab, Gaithersburg, MD 20899 USA. RP Lapena, AM (reprint author), Univ Calif Los Angeles, Dept Chem & Biochem, Los Angeles, CA 90095 USA. NR 26 TC 29 Z9 29 U1 0 U2 6 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 1999 VL 60 IS 1 BP R29 EP R32 DI 10.1103/PhysRevE.60.R29 PG 4 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA 218KC UT WOS:000081550900008 PM 11969873 ER PT J AU King, LB Gallimore, AD AF King, LB Gallimore, AD TI Identifying charge-exchange collision products within the ion-energy distribution of electrostatically accelerated plasmas SO PHYSICS OF PLASMAS LA English DT Article AB When used in flowing electrostatically accelerated plasmas, electrostatic energy analyzers, such as Retarding Potential Analyzers (RPA's) or Cylindrical Mirror Analyzers (CMA's), occasionally yield data which seem implausible: for a known applied plasma acceleration voltage, electrostatic analyzers may indicate populations of ions having voltages much greater than that available through the electrostatic discharge. The process responsible for this phenomenon is resonant charge-exchange (CEX) collisions between ions of different charge species. Through the transfer of electrons, an ion of charge n(+) can appear in an electrostatic analyzer with equivalent voltage of n-times the available acceleration potential. This paper discusses the phenomena responsible for the appearance of such high-voltage ions in the measured voltage distribution function and presents evidence for such reactions in the flowing xenon plasma produced by a Hall-effect current accelerator designed for spacecraft propulsion. For a 300 V applied potential on the Hall accelerator electrodes, CEX collisions are shown to produce ions having voltages as high as 800 V when measured using an electrostatic analyzer. (C) 1999 American Institute of Physics. [S1070-664X(99)02307-1]. C1 Univ Michigan, Plasmadynam & Elect Propuls Lab, Ann Arbor, MI 48109 USA. RP King, LB (reprint author), NIST, Time & Frequency Div 847, 325 Broadway, Boulder, CO 80303 USA. NR 15 TC 7 Z9 7 U1 0 U2 4 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD JUL PY 1999 VL 6 IS 7 BP 2936 EP 2942 DI 10.1063/1.873251 PG 7 WC Physics, Fluids & Plasmas SC Physics GA 208LV UT WOS:000080993600035 ER PT J AU Tan, NCB Bauer, BJ Plestil, J Barnes, JD Liu, D Matejka, L Dusek, K Wu, WL AF Tan, NCB Bauer, BJ Plestil, J Barnes, JD Liu, D Matejka, L Dusek, K Wu, WL TI Network structure of bimodal epoxies - a small angle X-ray scattering study SO POLYMER LA English DT Article; Proceedings Paper CT Symposium on 20-20 Vision of Polymer Science - The Next 2 Decades CY MAY 13-15, 1999 CL UNIV AKRON, AKRON, OHIO HO UNIV AKRON DE X-ray scattering; small angle neutron scattering; epoxy ID NEUTRON-SCATTERING AB Small angle X-ray scattering measurements were performed on epoxies to determine their network structure. To provide the necessary scattering contrast the epoxy monomer used was a partially brominated diglycidyl ether of bisphenol A and the cross-linking agents were linear, low polydispersity, amine terminated poly(propylene oxide)s, Samples with both single and bimodal molecular weight distributions of cross-linking agent were prepared. A pronounced scattering maximum was observed in all networks and it can be interpreted in terms of correlation holes. Networks cured with a mixture of two cross-linking agents with different molecular weights, i.e, bimodal networks, exhibited scattering maxima at significantly lower scattering Vector (q) than was observed for any single amine networks. In model bimodal epoxy graft copolymers with nearly identical chemical structure as the networks the shift to low q was barely perceptible. Experimental results from both epoxies and model graft copolymers are compared to a model calculation in order to establish a methodology to reduce molecular structure information from X-ray results. (C) 1999 Published by Elsevier Science Ltd. All rights reserved. C1 NIST, Div Polymers, Gaithersburg, MD 20899 USA. Acad Sci Czech Republ, Inst Macromol Chem, Prague, Czech Republic. RP Wu, WL (reprint author), NIST, Div Polymers, B 320,Bldg 224, Gaithersburg, MD 20899 USA. RI Plestil, Josef/H-6807-2014; Matejka, Libor/G-9383-2014; Dusek, Karel /I-5692-2014 NR 9 TC 21 Z9 21 U1 0 U2 10 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 JUL PY 1999 VL 40 IS 16 BP 4603 EP 4614 DI 10.1016/S0032-3861(99)00096-8 PG 12 WC Polymer Science SC Polymer Science GA 189LE UT WOS:000079905600020 ER PT J AU Greenberg, CC Foster, MD Turner, CM Corona-Galvan, S Cloutet, E Butler, PD Hammouda, B Quirk, RP AF Greenberg, CC Foster, MD Turner, CM Corona-Galvan, S Cloutet, E Butler, PD Hammouda, B Quirk, RP TI Effective interaction parameter between topologically distinct polymers SO POLYMER LA English DT Article; Proceedings Paper CT Symposium on 20-20 Vision of Polymer Science - The Next 2 Decades CY MAY 13-15, 1999 CL UNIV AKRON, AKRON, OHIO HO UNIV AKRON DE star polystyrene; linear polystyrene; small angle neutron scattering (SANS) ID ANGLE NEUTRON-SCATTERING; PHASE-BEHAVIOR; THETA-STATES; BLENDS; MISCIBILITY; MICROSTRUCTURE; POLYBUTADIENE; COPOLYMERS AB The magnitude of the thermodynamic interaction in a bulk binary homopolymer blend due to regular branching alone has been estimated from small angle neutron scattering (SANS) measurements for the first time using blends of star and linear poly(styrene)s of well defined structure. The value of chi for a blend of deuterated four arm star (M = 100 000 g/mol) with hydrogenous linear polystyrene (M = 132 000 g/ mel) of comparable molecular weight is chi = 0.1278/T - 0.0002 over the temperature range of 120-225 degrees C for a segment volume of 100 cm(3)/ mel. The contribution to chi ascribable to architecture effects is just distinguishable from that due to isotopic substitution alone and in surprisingly good agreement with an approximate prediction from a mean field theory. The precise value of chi varies depending on which component is labeled. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Univ Akron, Maurice Morton Inst Polymer Sci, Akron, OH 44325 USA. E Stroudsburg Univ, Dept Chem, E Stroudsburg, PA 18301 USA. Ind Negromex SA, Tampico 89600, Mexico. NIST, Ctr Neutron Res, Gaithersburg, MD 20899 USA. RP Foster, MD (reprint author), Univ Akron, Maurice Morton Inst Polymer Sci, Akron, OH 44325 USA. RI Butler, Paul/D-7368-2011; Cloutet, Eric/B-3487-2014 OI Cloutet, Eric/0000-0002-5616-2979 NR 29 TC 30 Z9 30 U1 0 U2 13 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 JUL PY 1999 VL 40 IS 16 BP 4713 EP 4716 DI 10.1016/S0032-3861(99)00083-X PG 4 WC Polymer Science SC Polymer Science GA 189LE UT WOS:000079905600032 ER PT J AU Thomas, CL Bur, AJ AF Thomas, CL Bur, AJ TI Optical monitoring of polypropylene injection molding SO POLYMER ENGINEERING AND SCIENCE LA English DT Article ID POLYMER AB We have constructed an optical fiber sensor for monitoring injection molding and we have developed a model to describe sensor behavior. The sensor consists of a sapphire window at the end of a sleeved ejector pin into which an optical fiber is inserted. The optical view with this sensor is through the thickness of the molded product. The measured optical signal was light that transmitted through the resin, reflected off the back wall of the mold, and retraced its path through the resin to the optical sensor, i.e., light transmitted through twice the thickness of the resin. While monitoring polypropylene during the packing and cooling phase of the molding cycle, we observed a decrease in light intensity due to scattering of light by the growing microcrystals. A characteristic minimum in the transmitted Light intensity versus time curve is attributed to scattering by growing crystalline spherulites at the core of the molded product. Cavity pressure was also measured and was found to be an essential parameter in the process model. The model illustrates how temperature, pressure, and crystallinity affect the detected light intensity and clarifies the roles that temperature and pressure play in the crystallization process. C1 Univ Utah, Dept Mech Engn, Salt Lake City, UT 84112 USA. NIST, Div Polymers, Gaithersburg, MD 20899 USA. RP Thomas, CL (reprint author), Univ Utah, Dept Mech Engn, Salt Lake City, UT 84112 USA. NR 25 TC 18 Z9 18 U1 0 U2 4 PU SOC PLASTICS ENG INC PI BROOKFIELD PA 14 FAIRFIELD DR, BROOKFIELD, CT 06804-0403 USA SN 0032-3888 J9 POLYM ENG SCI JI Polym. Eng. Sci. PD JUL PY 1999 VL 39 IS 7 BP 1291 EP 1302 DI 10.1002/pen.11516 PG 12 WC Engineering, Chemical; Polymer Science SC Engineering; Polymer Science GA 225WU UT WOS:000081989600015 ER PT J AU Doi, T Vorburger, T Sullivan, P AF Doi, T Vorburger, T Sullivan, P TI Effects of defocus and algorithm on optical step height calibration SO PRECISION ENGINEERING-JOURNAL OF THE AMERICAN SOCIETY FOR PRECISION ENGINEERING LA English DT Article DE focus; interferometric microscopy; numerical aperture correction factor; phase-measuring; phase-shifting; step height; surface; topography ID PROFILOMETRY; MICROSCOPE; INTERFEROMETRY; SURFACES; MIRAU AB Defocus effects on step height measurements by interferometric microscopy are estimated using different algorithms to calculate the step height. The interferometric microscope here is a Mirau-type with a 20x objective and a numerical aperture (NA) of 0.4. Although the focus is adjusted within the range of the depth of focus, a defocus corresponding to 4 fringes (similar to 1.3 mu m) distorts the measured profile into a curve with a radius of curvature of about 24 m. The effect of this distortion on step height determination by a basic ISO step height algorithm is estimated to be 0.11 nm/fringe. An algorithm developed by NIST and a second-order fitted LSO step-height algorithm show good robustness against defocus errors. Because of sample imperfection, a discrepancy of about 1% exists among step-height values determined by the different algorithms at the optimum fringe contrast position. It has been painted out theoretically that the NA correction factor varies with the difference of optical path length between the sample and the reference surface. However, in our case, the changes of optical path length do not change the NA correction factor by more than 0.3%. Published by Elsevier Science Inc. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Vorburger, T (reprint author), Natl Inst Stand & Technol, Bldg 220,Room A117, Gaithersburg, MD 20899 USA. NR 22 TC 9 Z9 9 U1 0 U2 1 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 USA SN 0141-6359 J9 PRECIS ENG JI Precis. Eng.-J. Am. Soc. Precis. Eng. PD JUL PY 1999 VL 23 IS 3 BP 135 EP 143 DI 10.1016/S0141-6359(99)00002-1 PG 9 WC Engineering, Multidisciplinary; Engineering, Manufacturing; Nanoscience & Nanotechnology; Instruments & Instrumentation SC Engineering; Science & Technology - Other Topics; Instruments & Instrumentation GA 217UV UT WOS:000081518000001 ER PT J AU O'Hare, PAG AF O'Hare, PAG TI Thermochemistry of silicon-containing materials SO PURE AND APPLIED CHEMISTRY LA English DT Article; Proceedings Paper CT 15th International Conference on Chemical Thermodynamics CY JUL 26-AUG 01, 1998 CL UNIV PORTO, OPORTO, PORTUGAL SP Int Union Pure & Appl Chem HO UNIV PORTO ID STANDARD MOLAR ENTHALPY; TEMPERATURE 298.15 K; COMBUSTION CALORIMETRIC DETERMINATION; THERMODYNAMIC PROPERTIES; FLUORINE; SILICIDES; TRANSITION; DISSOCIATION; DISILICIDE; ENERGY AB A brief survey is given of the thermochemistry of a number of silicon-containing substances that are of interest in modern technology. Among those discussed are: silicalite (SiO2), silicon disulfide (SiS2), the crystalline and vitreous forms of silicon diselenide (SiSenu), silicon sesquitelluride (Si2Te3), silicon nitride (Si3N4), and vanadium disilicide (VSi2). C1 Natl Inst Stand & Technol, Phys & Chem Properties Div, Gaithersburg, MD 20899 USA. RP O'Hare, PAG (reprint author), Natl Inst Stand & Technol, Phys & Chem Properties Div, Gaithersburg, MD 20899 USA. NR 23 TC 8 Z9 8 U1 2 U2 8 PU BLACKWELL SCIENCE LTD PI OXFORD PA P O BOX 88, OSNEY MEAD, OXFORD OX2 0NE, OXON, ENGLAND SN 0033-4545 J9 PURE APPL CHEM JI Pure Appl. Chem. PD JUL PY 1999 VL 71 IS 7 BP 1243 EP 1248 DI 10.1351/pac199971071243 PG 6 WC Chemistry, Multidisciplinary SC Chemistry GA 255VG UT WOS:000083690400008 ER PT J AU Bice, AE Block, MR Caillibot, P Cascio, J DeVries, C Gerber, MA Juran, JM Kammer, R Line, H Mazza, S Munro, RA Reid, RD Stamatis, DH West, J AF Bice, AE Block, MR Caillibot, P Cascio, J DeVries, C Gerber, MA Juran, JM Kammer, R Line, H Mazza, S Munro, RA Reid, RD Stamatis, DH West, J TI What they're saying about standards SO QUALITY PROGRESS LA English DT Editorial Material C1 DNV Certificat, Houston, TX USA. Hydro Quebec, Montreal, PQ, Canada. Polaroid Corp, Cambridge, MA 02139 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. GM Corp, Supplier Qual Dev, Detroit, MI 48202 USA. RP Bice, AE (reprint author), DNV Certificat, Houston, TX USA. NR 1 TC 0 Z9 0 U1 0 U2 1 PU AMER SOC QUALITY CONTROL-ASQC PI MILWAUKEE PA ASQC MEMBERSHIP MANAGER 611 E. WISCONSIN AVENUE, MILWAUKEE, WI 53202 USA SN 0033-524X J9 QUAL PROG JI Qual. Prog. PD JUL PY 1999 VL 32 IS 7 BP 28 EP 32 PG 5 WC Engineering, Multidisciplinary; Engineering, Industrial; Management; Operations Research & Management Science SC Engineering; Business & Economics; Operations Research & Management Science GA 214GY UT WOS:000081321300023 ER PT J AU Zhu, X Yee, JH Strobel, DF Wang, XL Greenwald, RA AF Zhu, X Yee, JH Strobel, DF Wang, XL Greenwald, RA TI On the numerical modelling of middle atmosphere tides SO QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY LA English DT Article DE mesosphere; spectral model; stratosphere ID RESOLUTION DOPPLER IMAGER/UARS; DIURNAL MIGRATING TIDE; SOLAR-RADIATION; SPECTRAL MODEL; TEMPERATURE-GRADIENTS; SEMIDIURNAL TIDE; HOUGH COMPONENTS; GRAVITY-WAVE; WATER-VAPOR; MEAN WINDS AB A linear, spectral, tidal model for middle atmosphere thermal tides has been developed. The spectral model is based on horizontal vorticity and divergence equations, and the vertical structure equation for the geopotential is solved with appropriate boundary conditions. Such an approach yields a stable temperature field and a consistent velocity field for the diurnal tide around the apparent singularity at latitudes of +/-30 degrees. Thermal forcing consists of solar near-infrared heating by water vapour in the troposphere based on an accurate and efficient algorithm and the solar radiation heating by ozone and molecular oxygen in the stratosphere, mesosphere and lower thermosphere. The calculated diurnal and semidiurnal temperatures are in good agreement with the recent temperature measurements derived from the National Aeronautics and Space Administration Upper Atmosphere Research Satellite (UARS) and Light Detection and Ranging around the midlatitude and high-latitude stratopause where ozone heating is a major source of tidal variability. Some discrepancies between the current model output and the wind measurements derived from the High-Resolution Doppler Imager and Wind Imaging Interferometer on board UARS still exist. A sensitivity study shows the need for improved modelling of tropospheric heating rates and parametrization of eddy diffusion coefficients in the upper mesosphere in order to reduce these discrepancies. C1 Johns Hopkins Univ, Appl Phys Lab, Laurel, MD 20723 USA. Johns Hopkins Univ, Baltimore, MD USA. NOAA, Climate Predict Ctr, Silver Spring, MD USA. RP Zhu, X (reprint author), Johns Hopkins Univ, Appl Phys Lab, Johns Hopkins Rd, Laurel, MD 20723 USA. RI Wang, Julian/C-3188-2016; Zhu, Xun/C-2097-2016; OI Zhu, Xun/0000-0001-7860-6430; Greenwald, Raymond/0000-0002-7421-5536 NR 45 TC 14 Z9 14 U1 0 U2 4 PU ROYAL METEOROLOGICAL SOC PI READING PA 104 OXFORD ROAD, READING, BERKS, ENGLAND RG1 7LJ SN 0035-9009 J9 Q J ROY METEOR SOC JI Q. J. R. Meteorol. Soc. PD JUL PY 1999 VL 125 IS 557 BP 1825 EP 1857 DI 10.1002/qj.49712555717 PN A PG 33 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 220VM UT WOS:000081688500016 ER PT J AU McLaughlin, WL Miller, SD Saylor, MC Kovacs, A Wojnarovits, L AF McLaughlin, WL Miller, SD Saylor, MC Kovacs, A Wojnarovits, L TI A preliminary communication on an inexpensive mass-produced high-dose polymeric dosimeter based on optically-stimulated luminescence SO RADIATION PHYSICS AND CHEMISTRY LA English DT Article; Proceedings Paper CT 10th International Meeting on Radiation Processing CY MAY 11-16, 1997 CL ANAHEIM, CA AB Polymeric thin films (0.5, 0.42, 0.25 and 0.08 mm thicknesses), containing a microcrystalline dispersion of a proprietary optically stimulated fluor in a plastic matrix, have been developed to measure and image high doses, using a simple, inexpensive table-top fluorimeter dedicated to a fast repetitive readout for large-scale routine dosimetry. The useable absorbed dose range of the system is 5 x 10(1) to 2 x 10(5) Gy, with an approximately linear function of relative light emission vs absorbed dose, and a random (type A) uncertainty (coverage factor 1) of dose interpretation of similar to 3%. The dosimeters are produced in very large reproducible quantities and provide a relatively fast simple analysis based on blue-light stimulation of stable, radiation-induced trapped-charged colour-centre states with emitted red-light photometric readout. Unlike thermoluminescence (TL), the optically stimulated luminescence (OSL) emission at room temperature does not appreciably anneal the luminescent centres, so that stored excited states in the radiation-induced colour centres are stable through many readout cycles, affording archival dosimetry data capability. Dosimeter stability, reproducibility, temperature dependence, humidity dependence, sensitivity to ambient light, and rate dependence are reported on. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 NIST, Ionizing Radiat Div, Phys Lab, Gaithersburg, MD 20899 USA. Sunna Syst Corp, Richland, WA 99352 USA. Special Proc Serv LC, Vienna, VA 22182 USA. Hungarian Acad Sci, Inst Isotopes & Surface Chem, H-1525 Budapest, Hungary. RP McLaughlin, WL (reprint author), NIST, Ionizing Radiat Div, Phys Lab, Gaithersburg, MD 20899 USA. NR 13 TC 12 Z9 12 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0969-806X J9 RADIAT PHYS CHEM JI Radiat. Phys. Chem. PD JUL PY 1999 VL 55 IS 3 BP 247 EP 253 DI 10.1016/S0969-806X(98)00349-1 PG 7 WC Chemistry, Physical; Nuclear Science & Technology; Physics, Atomic, Molecular & Chemical SC Chemistry; Nuclear Science & Technology; Physics GA 214YV UT WOS:000081355900003 ER PT J AU Phaneuf, RA Havener, CC Dunn, GH Muller, A AF Phaneuf, RA Havener, CC Dunn, GH Muller, A TI Merged-beams experiments in atomic and molecular physics SO REPORTS ON PROGRESS IN PHYSICS LA English DT Review ID ELECTRON-IMPACT EXCITATION; ABSOLUTE CROSS-SECTIONS; ION STORAGE-RING; ENHANCED DIELECTRONIC RECOMBINATION; STIMULATED RADIATIVE RECOMBINATION; ENERGY-LOSS TECHNIQUE; HIGHLY-CHARGED IONS; 3S(2) S-1->3S3P P-3; VERY-LOW ENERGIES; DISSOCIATIVE-RECOMBINATION AB The merged-beams technique is powerful for the experimental study of certain classes of atomic and molecular processes that cannot be as readily or accurately addressed by other methods. The principal advantages of the technique are the ability to make quantitative studies of collisional interactions with high resolution at low relative energies, to collect products that have undergone appreciable angular scattering, and to investigate processes involving short-lived or chemically-reactive species. Despite continuing advances in ion-source and particle-beam technologies, merged-beams experiments remain a challenge, constituting a relatively small but growing fraction of the worldwide effort in atomic and molecular collisions research. This review outlines the fundamental principles of the merged-beams method, reviews techniques and progress, and focuses on three active programs to highlight the advantages of the method for addressing fundamental questions in atomic and molecular physics. C1 Univ Nevada, Dept Phys, Reno, NV 89557 USA. Oak Ridge Natl Lab, Div Phys, Oak Ridge, TN 37831 USA. Univ Colorado, JILA, Boulder, CO 80309 USA. NIST, Boulder, CO 80309 USA. Univ Giessen, Inst Kernphys, D-35392 Giessen, Germany. RP Phaneuf, RA (reprint author), Univ Nevada, Dept Phys, Reno, NV 89557 USA. RI Muller, Alfred/A-3548-2009 OI Muller, Alfred/0000-0002-0030-6929 NR 141 TC 72 Z9 72 U1 3 U2 8 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0034-4885 J9 REP PROG PHYS JI Rep. Prog. Phys. PD JUL PY 1999 VL 62 IS 7 BP 1143 EP 1180 DI 10.1088/0034-4885/62/7/202 PG 38 WC Physics, Multidisciplinary SC Physics GA 221ZA UT WOS:000081756700002 ER PT J AU Zhang, NF Postek, MT Larrabee, RD Vladar, AE Keery, WJ Jones, SN AF Zhang, NF Postek, MT Larrabee, RD Vladar, AE Keery, WJ Jones, SN TI Image sharpness measurement in the scanning electron microscope - Part III SO SCANNING LA English DT Article DE image analysis; Fourier transform; metrology; kurtosis; scanning electron microscope ID ASTIGMATISM CORRECTION METHOD AB Fully automated or semi-automated scanning electron microscopes (SEM) are now commonly used in semiconductor production and other forms of manufacturing. Testing and proving that the instrument is performing at a satisfactory level of sharpness is an important aspect of quality control. The application of Fourier analysis techniques to the analysis of SEM images is a useful methodology for sharpness measurement. In this paper, a statistical measure known as the multivariate kurtosis is proposed as an additional useful measure of the sharpness of SEM images. Kurtosis is designed to be a measure of the degree of departure of a probability distribution. For selected SEM images, the two-dimensional spatial Fourier transforms were computed. Then the bivariate kurtosis of this Fourier transform was calculated as though it were a probability distribution. Kurtosis has the distinct advantage that it is a parametric (i.e., a dimensionless) measure and is sensitive to the presence of the high spatial frequencies necessary for acceptable levels of image sharpness. The applications of this method to SEM metrology will be discussed. C1 Natl Inst Stand & Technol, Stat Engn Div, Gaithersburg, MD 20899 USA. RP Zhang, NF (reprint author), Natl Inst Stand & Technol, Stat Engn Div, Stop 8980, Gaithersburg, MD 20899 USA. NR 13 TC 41 Z9 42 U1 1 U2 8 PU FAMS INC PI MAHWAH PA BOX 832, MAHWAH, NJ 07430-0832 USA SN 0161-0457 J9 SCANNING JI Scanning PD JUL-AUG PY 1999 VL 21 IS 4 BP 246 EP 252 PG 7 WC Instruments & Instrumentation; Microscopy SC Instruments & Instrumentation; Microscopy GA 227UQ UT WOS:000082098700004 PM 10483879 ER PT J AU Beckmen, KB Ylitalo, GM Towell, RG Krahn, MM O'Hara, TM Blake, JE AF Beckmen, KB Ylitalo, GM Towell, RG Krahn, MM O'Hara, TM Blake, JE TI Factors affecting organochlorine contaminant concentrations in milk and blood of northern fur seal (Callorhinus ursinus) dams and pups from St. George Island, Alaska SO SCIENCE OF THE TOTAL ENVIRONMENT LA English DT Article DE PCBs; organochlorine contaminants; northern fur seal; milk; marine mammal; DDT; Pribilof Islands; pinniped; biomagnification factors ID POLYCHLORINATED-BIPHENYLS PCBS; WHALES DELPHINAPTERUS-LEUCAS; BALTIC GRAY SEAL; HALICHOERUS-GRYPUS; STRIPED DOLPHIN; RESIDUE LEVELS; REPRODUCTIVE TRANSFER; TURSIOPS-TRUNCATUS; LAWRENCE ESTUARY; MARINE MAMMALS AB Levels of organochlorine contaminants in blood of northern fur seal (Callorhinus ursinus) pups and the blood and milk of their dams early in the lactation period are reported here. The contaminants included 15 selected individual polychlorinated biphenyl (PCB) congeners and DDT metabolites identified through high-performance liquid chromatography. Congeners CB-77, -81, -126, -169 and -189 were below the limits of detection in milk and blood samples analyzed. Congener-specific concentrations of PCBs in the blood of pups were compared based on the age of their dam (less than or equal to 5 years or >7 years). Pups of young (presumably primiparous) darns had significantly elevated levels of CBs-101, -118, -128, -138, -153/87, -170/194, and -180 than pups of older (multiparous) dams. Congeners CB-128 and -170/194 were detected in the blood of pups of young dams but not in the blood of pups of older dams nor in any of the darns blood. Additionally, pups had higher blood levels in seven of 10 detected PCB congeners as compared to the levels measured in milk when adjusted for lipid content. Levels of DDT metabolites and toxic equivalency quotients of dioxin-like congeners followed similar trends. Lipid-normalized concentrations of CB-101 and total PCBs were significantly higher in the blood of dams than in their milk. CB-128, -156, -157, -170/194, p,p'-DDT, o,p'-DDT, p,p'-DDD and o,p'-DDD were not detected in dam blood samples, but were detected in milk samples. Calculation of 'biomagnification factors' from milli to pup blood indicated a biomagnification of CB-101, -105. -118, -1381 -153/87, and -180. Significant mean accumulation factors ranged from 15 to 7.5. Inter-annual differences in exposure levels and specific congener concentrations in both milk and blood were apparent. Northern fur seal pups, especially first-born, have a substantial exposure to organochlorine contaminants at a critical developmental stage. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Alaska, Inst Arctic Biol, Fairbanks, AK 99775 USA. Natl Marine Fisheries Serv, Environm Conservat Div, NW Fisheries Sci Ctr, NOAA, Seattle, WA 98112 USA. Natl Marine Fisheries Serv, Natl Marine Mammal Lab, NOAA, Seattle, WA 98115 USA. Dept Wildlife Management, Barrow, AK 99723 USA. RP Beckmen, KB (reprint author), Univ Alaska, Inst Arctic Biol, POB 757000, Fairbanks, AK 99775 USA. EM ftkbb@uaf.edu NR 93 TC 53 Z9 54 U1 2 U2 14 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0048-9697 EI 1879-1026 J9 SCI TOTAL ENVIRON JI Sci. Total Environ. PD JUL 1 PY 1999 VL 231 IS 2-3 BP 183 EP 200 DI 10.1016/S0048-9697(99)00094-7 PG 18 WC Environmental Sciences SC Environmental Sciences & Ecology GA 221CR UT WOS:000081706900009 PM 10472134 ER PT J AU Enabnit, DB Brown, MB AF Enabnit, DB Brown, MB TI Electronic charting at NOAA SO SEA TECHNOLOGY LA English DT Article C1 NOAA, Off Coast Survey, Elect Navigat Chart Program, Washington, DC 20250 USA. NOAA, Elect Navigat Chart Coast Survey, Washington, DC 20250 USA. RP Enabnit, DB (reprint author), NOAA, Off Coast Survey, Elect Navigat Chart Program, Washington, DC 20250 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU COMPASS PUBL INC PI ARLINGTON PA SUITE 1000 1117 N 19 ST, ARLINGTON, VA 22209 USA SN 0093-3651 J9 SEA TECHNOL JI Sea Technol. PD JUL PY 1999 VL 40 IS 7 BP 39 EP 41 PG 3 WC Engineering, Ocean SC Engineering GA 222NP UT WOS:000081791900007 ER PT J AU Lamaze, GP Chen-Mayer, H Badding, M Laby, L AF Lamaze, GP Chen-Mayer, H Badding, M Laby, L TI In situ measurement of lithium movement in thin film electrochromic coatings using cold neutron depth profiling SO SURFACE AND INTERFACE ANALYSIS LA English DT Article DE NRA; nuclear reaction analysis; depth profile; Li AB Direct analysis of lithium movement within multilayer thin-film electrochromic (EC) coatings has been performed by cold neutron depth profiling (CNDP), Transfer of lithium between a counter-electrode layer and an EC tungsten trioxide layer controls the optical density of the EC coating. The lithium profiles have been measured using the CNDP instrument at the Center for Neutron Research at the National institute of Standards and Technology, The lithium depth profiles are based on measurement of the energy of alpha particles from the Li-6(n,alpha)H-3 reaction, The alpha particles lose energy as they exit the film and this energy loss pro, ides direct measurement of the depth of the originating lithium nucleus. In this case, in situ measurements were taken with different bias voltages on the film layers. The bias causes the lithium to migrate between different layers, changing the optical density of the films. A great advantage of the CNDP technique is that it is non-destructive, which allows repeated observation of the lithium movement. Results of simultaneous optical transmission measurements and lithium profile measurements are reported. Copyright (C) 1999 John Wiley & Sons, Ltd. C1 Natl Inst Stand & Technol, Nucl Methods Grp, Gaithersburg, MD 20899 USA. SAGE Electrochrom, Piscataway, NJ 08854 USA. RP Lamaze, GP (reprint author), Natl Inst Stand & Technol, Nucl Methods Grp, Gaithersburg, MD 20899 USA. NR 6 TC 2 Z9 2 U1 0 U2 4 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 1999 VL 27 IS 7 BP 644 EP 647 DI 10.1002/(SICI)1096-9918(199907)27:7<644::AID-SIA554>3.0.CO;2-4 PG 4 WC Chemistry, Physical SC Chemistry GA 216BK UT WOS:000081420500005 ER PT J AU Powell, CJ Shimizu, R AF Powell, CJ Shimizu, R TI Summary of ISO TC 201 standards: Introduction SO SURFACE AND INTERFACE ANALYSIS LA English DT Editorial Material DE ISO TC 201 on Surface Chemical Analysis; standards; surface analysis AB An introduction is given to a planned series of short summaries of international standards developed by Technical Committee 201 on Surface Chemical Analysis of the International Organization for Standardization (ISO), The purpose of these summaries is to inform scientists of the existence of these standards, to give information on the standard and its intended use, and to indicate where the full text of the standard can be obtained. An overview is also given of planned new standards currently being developed by ISO/TC 201, Copyright (C) 1999 John Wiley & Sons, Ltd. C1 Natl Inst Stand & Technol, Surface & Microanal Sci Div, Gaithersburg, MD 20899 USA. Osaka Univ, Fac Engn, Dept Appl Phys, Suita, Osaka 565, Japan. RP Powell, CJ (reprint author), Natl Inst Stand & Technol, Surface & Microanal Sci Div, Gaithersburg, MD 20899 USA. NR 2 TC 3 Z9 3 U1 0 U2 0 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 1999 VL 27 IS 7 BP 691 EP 692 DI 10.1002/(SICI)1096-9918(199907)27:7<691::AID-SIA639>3.0.CO;2-T PG 2 WC Chemistry, Physical SC Chemistry GA 216BK UT WOS:000081420500011 ER PT J AU Peylin, P Ciais, P Denning, AS Tans, PP Berry, JA White, JWC AF Peylin, P Ciais, P Denning, AS Tans, PP Berry, JA White, JWC TI A 3-dimensional study of delta O-18 in atmospheric CO2: contribution of different land ecosystems SO TELLUS SERIES B-CHEMICAL AND PHYSICAL METEOROLOGY LA English DT Article ID SURFACE PARAMETERIZATION SIB2; GENERAL-CIRCULATION MODEL; OXYGEN ISOTOPE FRACTIONATION; CARBON-DIOXIDE; WATER-VAPOR; O-18; SIMULATIONS; FLUXES; GCMS; PRECIPITATION AB Land biospheric carbon exchange associated with respiration and photosynthesis exerts a major control on the oxygen isotope composition (delta(18)O) of atmospheric CO2 especially with respect to the seasonal cycle. In particular, an important feature that requires our attention is the phase of the seasonal cycle of delta(18)O which lags CO2 by one month in the Arctic. We have developed a global parameterization of the land biotic exchange of O-18 in CO2, which has been prescribed in an atmospheric 3-D transport model in order to simulate the global atmospheric distribution of delta(18)O. Furthermore, we have separated in the model the specific contribution of different regions of the globe to the seasonal and latitudinal variation of delta(18)O. The model simulated values are compared in detail with atmospheric observations made at 22 different remote stations. The respective role of respiration vs, photosynthesis in determining the phase and amplitude of the delta(18)O seasonal cycle is also analyzed. Based on a good agreement between our model simulation and the atmospheric observations, we observe that the large seasonal cycle of delta(18)O at high latitudes is mainly due to the respiratory fluxes of all extra-tropical ecosystems while for CO2 the relative contributions of photosynthesis and respiration to the overall seasonal cycle are similar. Geographically, the CO2 exchanges with the northern Siberian ecosystem dominate the delta(18)O seasonality at all remote stations of the northern hemisphere, reflecting the strongly continental climate of that region. C1 CEA, Lab Sci Climat & Environm, LSCE, F-91191 Gif Sur Yvette, France. Colorado State Univ, Dept Atmospher Sci, Ft Collins, CO 80523 USA. NOAA, Climate Monitoring & Diagnost Lab, Boulder, CO 80303 USA. Carnegie Inst Washington, Dept Plant Biol, Stanford, CA 94305 USA. Univ Colorado, Inst Arctic & Alpine Res, Boulder, CO 80303 USA. Univ Colorado, Dept Geol Sci, Boulder, CO 80303 USA. RP Peylin, P (reprint author), CEA, Lab Sci Climat & Environm, LSCE, F-91191 Gif Sur Yvette, France. RI Berry, Joseph/B-8211-2009; White, James/A-7845-2009; Denning, Scott/F-4974-2011; Vuichard, Nicolas/A-6629-2011 OI Berry, Joseph/0000-0002-5849-6438; White, James/0000-0001-6041-4684; Denning, Scott/0000-0003-3032-7875; NR 47 TC 51 Z9 52 U1 0 U2 6 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0280-6509 J9 TELLUS B JI Tellus Ser. B-Chem. Phys. Meteorol. PD JUL PY 1999 VL 51 IS 3 BP 642 EP 667 DI 10.1034/j.1600-0889.1999.t01-2-00006.x PG 26 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 220JK UT WOS:000081661700006 ER PT J AU Ciattaglia, L Colombo, T Masarie, KA AF Ciattaglia, L Colombo, T Masarie, KA TI Continuous measurements of atmospheric CO2 at Jubany Station, Antarctica SO TELLUS SERIES B-CHEMICAL AND PHYSICAL METEOROLOGY LA English DT Article; Proceedings Paper CT 5th International CO(2) Conference CY SEP 08-12, 1997 CL CAIRNS, AUSTRALIA ID CARBON-DIOXIDE; MODEL; SINKS AB The first 4 years (1994-1997) of continuous atmospheric CO2 measurements from Jubany station located on the Antarctic peninsula are presented. Details are given on the station environment, meteorological conditions, instrumentation, and data selection strategy. The average seasonal cycle and annual growth rate are characterized and compared with other independent Antarctic CO2 measurement records. An analysis of diurnal behaviour and local meteorology and statistical variability in the measurements suggests that Jubany is a suitable site lot making systematic observations of CO2 that are representative of large wen-mixed air masses. C1 CNR, Ist Fis Atmosfera, Rome, Italy. Serv Meteorol AM, Mt Cimone, Sestola, Italy. Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. NOAA, Climate Monitoring & Diagnost Lab, Boulder, CO 80303 USA. RP Ciattaglia, L (reprint author), CNR, Ist Fis Atmosfera, Rome, Italy. NR 15 TC 6 Z9 7 U1 0 U2 0 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0280-6509 J9 TELLUS B JI Tellus Ser. B-Chem. Phys. Meteorol. PD JUL PY 1999 VL 51 IS 3 BP 713 EP 721 DI 10.1034/j.1600-0889.1999.t01-1-00011.x PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 220JK UT WOS:000081661700011 ER PT J AU Etcheto, J Boutin, J Dandonneau, Y Bakker, DCE Feely, RA Ling, RD Nightingale, PD Wanninkhof, R AF Etcheto, J Boutin, J Dandonneau, Y Bakker, DCE Feely, RA Ling, RD Nightingale, PD Wanninkhof, R TI Air-sea CO(2) flux variability in the equatorial Pacific Ocean near 100 degrees W SO TELLUS SERIES B-CHEMICAL AND PHYSICAL METEOROLOGY LA English DT Article; Proceedings Paper CT 5th International CO(2) Conference CY SEP 08-12, 1997 CL CAIRNS, AUSTRALIA ID NINO SOUTHERN OSCILLATION; EL-NINO; CARBON-DIOXIDE; EXCHANGE COEFFICIENT; TROPICAL PACIFIC; PARTIAL-PRESSURE; SURFACE-WATER; WIND SPEEDS; SATELLITE; TEMPERATURE AB The interannual variability of the CO(2) partial pressure (pCO(2oc)) in the surface layer of the east equatorial Pacific Ocean near 100 degrees W is studied and compared with the sea surface temperature (SST) monitored from satellites. This variability is shown to be correlated with the SST anomaly rather than with the temperature itself. The pCO(2oc) variability is related to the variability of the upwelling systems (the equatorial upwelling and the upwelling along the American coast), the main influence being from the coastal upwelling via the surface water advected from the east. A method is derived to interpolate the pCO(2oc) measurements using the SST satellite measurements. By combining the result with the exchange coefficient (K) deduced from the wind speed provided by satellite borne instruments we deduce the air-sea CO(2) flux and for the Ist rime we monitor continuously its temporal evolution. The variability of this flux is mainly due to the variability of K, with a clear seasonal variation. The flux obtained using the Liss and Merlivat (1986) relationship averaged From April 1985 to June 1997 in the region 97.5 degrees-107.5 degrees W 0-5 degrees S is 1.67 mole m(-2) yr(-1) of CO(2) leaving the ocean with an estimated accuracy of 30%. C1 UPMC, ORSTOM, CNRS, UMR 7617,LODYC, Paris, France. NOAA, Pacific Marine Environm Lab, Seattle, WA 98115 USA. Plymouth Marine Lab, Plymouth, Devon, England. NOAA, AOMI, Miami, FL USA. RP Etcheto, J (reprint author), UPMC, ORSTOM, CNRS, UMR 7617,LODYC, Paris, France. EM je@lodyc.jussieu.fr RI Nightingale, Philip/I-4324-2012; Bakker, Dorothee/E-4951-2015; Boutin, Jacqueline/M-2253-2016 OI Nightingale, Philip/0000-0001-7177-5469; Bakker, Dorothee/0000-0001-9234-5337; NR 43 TC 12 Z9 12 U1 0 U2 3 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 0280-6509 J9 TELLUS B JI Tellus Ser. B-Chem. Phys. Meteorol. PD JUL PY 1999 VL 51 IS 3 BP 734 EP 747 DI 10.1034/j.1600-0889.1999.t01-1-00013.x PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 220JK UT WOS:000081661700013 ER PT J AU Clayton, EC Peng, YG Means, LW Ramsdell, JS AF Clayton, EC Peng, YG Means, LW Ramsdell, JS TI Working memory deficits induced by single but not repeated exposures to domoic acid SO TOXICON LA English DT Article ID HIPPOCAMPAL DAMAGE; MICE; MUSSELS; RATS; NEUROTOXICITY; DEGENERATION; INJECTIONS; SEQUELAE; RECEPTOR; POISON AB Single injections of domoic acid, given either intraperitoneally to mice or directly into the hippocampal formation of rats, have been shown to impair learning on the place version of the Morris water maze task and the eight arm radial maze task. The present study was designed to test whether both single and repeated exposures of intraperitoneally administered domoic acid (1.0 or 2.0 mg/kg) impair spatial working memory in mice on a delayed matching-to-sample task. DBA strain mice were given a series of four injections over a 7-day period consisting of either saline or one of two doses of domoic acid. During the 18 days of testing, each subject was given one trial per day consisting of one information run, followed by three test runs. On non-alternation days (days in which the correct response was the same as the preceding day) the saline injected group significantly outperformed the single injection 2.0 mg/kg domoic acid group. This indicates that domoic acid-treated animals were incapable of forming a memory that persisted for 24 h and hence were less able to utilize the prior day's experience. However, the repeated exposure groups did not perform as poorly on non-alternation days than the single exposure groups, indicating that domoic acid may affect multiple mechanisms involved in memory consolidation. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Natl Ocean Serv, Marine Biomol Program, NOAA, Ctr Coastal Environm Hlth & Biomol Res, Charleston, SC 29412 USA. RP Ramsdell, JS (reprint author), Natl Ocean Serv, Marine Biomol Program, NOAA, Ctr Coastal Environm Hlth & Biomol Res, Charleston, SC 29412 USA. NR 22 TC 39 Z9 41 U1 0 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0041-0101 J9 TOXICON JI Toxicon PD JUL PY 1999 VL 37 IS 7 BP 1025 EP 1039 DI 10.1016/S0041-0101(98)00230-X PG 15 WC Pharmacology & Pharmacy; Toxicology SC Pharmacology & Pharmacy; Toxicology GA 200HB UT WOS:000080532600006 PM 10484738 ER PT J AU Potts, JC Manooch, CS AF Potts, JC Manooch, CS TI Observations on the age and growth of graysby and coney from the southeastern United States SO TRANSACTIONS OF THE AMERICAN FISHERIES SOCIETY LA English DT Article ID NORTH-CAROLINA; RED HIND AB The graysby Epinephelus cruentatus and coney E. fulvus are two uncommon groupers occurring off the southeastern coast of the United States. Limited recreational fishery data suggest that graysbies are being landed with increasing frequency in the area. From 1979 to 1997, 118 graysbies and 55 coneys were collected from the headboat fishery operating from North Carolina through the Dry Tortugas, Florida. Ages were estimated using transverse sections of sagittal otoliths. Graysbies ranged in total length (TL) from 180 to 405 mm and in age from 4 to 13 years. Coneys ranged from 150 to 397 mm TL and from 2 to 11 years old. Growth of the graysby is represented by the following models-derived from back-calculated lengths (L) at ages (t) and observed lengths at ages, respectively: L-t = 451(1 - e(-0.12(t+1.24))) and L-t = 446(1 - e(-0.13(t+1.51))). Coneys grew faster and had a smaller theoretical maximum size than graysbies: from back-calculated lengths at ages, L-t = 372(1 - e(-0.32(t-0.20))), and from observed lengths at ages, L-t = 385(1 - e(-0.32(t-0.49))). The weight-length relationships for graysby and coney are W = 8.81 X 10(-6)(L)(3.12) and W = 2.59 x 10(-5)(L)(2.94), respectively, where W = whole weight(g) and L = total length (mm). C1 NOAA, Natl Marine Fisheries Serv, SE Disheries Sci Ctr, Beaufort Lab, Beaufort, NC 28516 USA. RP Potts, JC (reprint author), NOAA, Natl Marine Fisheries Serv, SE Disheries Sci Ctr, Beaufort Lab, 101 Pivers Isl Rd, Beaufort, NC 28516 USA. NR 15 TC 10 Z9 10 U1 1 U2 5 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 1999 VL 128 IS 4 BP 751 EP 757 DI 10.1577/1548-8659(1999)128<0751:OOTAAG>2.0.CO;2 PG 7 WC Fisheries SC Fisheries GA 351XB UT WOS:000089183800020 ER PT J AU Gates, RS Ying, TN Wang, PS Yin, Z Chen, CI Wang, Y Hsu, SM AF Gates, RS Ying, TN Wang, PS Yin, Z Chen, CI Wang, Y Hsu, SM TI Mechanisms of alcohols in assisting the diamond grinding of ceramics SO TRIBOLOGY TRANSACTIONS LA English DT Article; Proceedings Paper CT 53rd Annual Meeting of the Society-of-Tribologists-and-Lubrication-Engineers CY MAY 17-21, 1998 CL DETROIT, MICHIGAN SP Soc Tribologists & Lubricat Engineers DE machining; ceramics; diamond; wear; oxidation AB A high molecular weight alcohol mixture has been found to offer higher grinding rates over time in machining ceramics using diamond tools. The benefits can be attributed to surface interactions of the alcohols with diamond surfaces forming a tenacious protective film under grinding conditions. The diamond particles are then protected from wear and remain sharp under grinding conditions. This allows sustained high machining rates over a much longer period of time. time. The ability of the alcohols to enhance grinding rates has been observed in a laboratory diamond cutter a vertical grinder; and a surface grinder A subsequent field trial was conducted in a manufacturing plant for five months, grinding cemented tungsten carbide cutting inserts using diamond tools. Results validated the observed laboratory benefits. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Gates, RS (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NR 5 TC 3 Z9 3 U1 0 U2 0 PU SOC TRIBOLOGISTS & LUBRICATION ENGINEERS PI PARK RIDGE PA 840 BUSSE HIGHWAY, PARK RIDGE, IL 60068 USA SN 1040-2004 J9 TRIBOL T JI Tribol. Trans. PD JUL PY 1999 VL 42 IS 3 BP 517 EP 522 DI 10.1080/10402009908982249 PG 6 WC Engineering, Mechanical SC Engineering GA 228MF UT WOS:000082139700011 ER PT J AU Deckman, DE Chen, CI Hsu, SM AF Deckman, DE Chen, CI Hsu, SM TI Effect of selected chemical compounds on the lubrication of silicon carbide SO TRIBOLOGY TRANSACTIONS LA English DT Article; Proceedings Paper CT 51st Annual Meeting of the Society-of-Tribologists-and-Lubrication-Engineers CY MAY 19-23, 1996 CL CINCINNATI, OHIO SP Soc Tribologists & Lubricat Engineers DE additive effect; boundary lubrication; carbides; chemistry; friction; wear ID STRUCTURAL CERAMICS; SLIDING FRICTION; WEAR AB A systematic study has been conducted to investigate the interactions between selected chemical compounds and silicon carbide under boundary lubrication conditions. A modified four-ball wear tester was used to evaluate the additive effectiveness on silicon carbides lubricated with a paraffinic base oil containing one weight percent of additives. Friction, wear and film morphology were observed for a range of chemical compounds containing chlorine, phosphorous, oxygen, and sulfur. Friction reduction was observed for chlorine containing compounds. At weight fraction of one percent under 40 kg lend, wear reduction was obtained by all phosphorous containing compounds, polypropylene glycols, and oleic acid At higher concentration and higher load some sulfur containing compounds also reduced wear significantly In general, all the effective wear reduction compounds generate films in the contact region. The films generated by phosphorous containing compounds appear to involve the iron impurity in the material. C1 Natl Inst Stand & Technol, Div Ceram, Gaithersburg, MD 20899 USA. RP Deckman, DE (reprint author), Natl Inst Stand & Technol, Div Ceram, Gaithersburg, MD 20899 USA. NR 25 TC 3 Z9 3 U1 0 U2 0 PU SOC TRIBOLOGISTS & LUBRICATION ENGINEERS PI PARK RIDGE PA 840 BUSSE HIGHWAY, PARK RIDGE, IL 60068 USA SN 1040-2004 J9 TRIBOL T JI Tribol. Trans. PD JUL PY 1999 VL 42 IS 3 BP 619 EP 625 DI 10.1080/10402009908982261 PG 7 WC Engineering, Mechanical SC Engineering GA 228MF UT WOS:000082139700023 ER PT J AU Volkman, JM AF Volkman, JM TI How do you learn from a river? Managing uncertainty in species conservation policy SO WASHINGTON LAW REVIEW LA English DT Article ID MANAGEMENT; WASHINGTON; NORTHWEST; SALMON; FISH; ACT AB As the Puget Sound region embarks on a new chapter in the story of the Endangered Species Act, experiences with fish and wildlife restoration efforts in other locations can be instructive. This Article reviews conservation efforts in the Columbia River Basin, and it explains the major role that scientific uncertainty plays in salmon conservation efforts. This discussion describes the debate between traditional fish and wildlife management, which focuses more on individual populations and mitigation technologies, and recent scientific reports, which urge more reliance on naturally functioning rivers and watersheds. The Article also describes a variety of learning tools that have helped in managing the scientific uncertainty that this debate reflects. These tools stem from an idea called adaptive management, a way of learning from experience. The tools now include initiatives in applied research, collaborative modeling, independent scientific advice, and ecological syntheses that shape policy development. Some of the insights this work has generated, particularly the importance of building conservation programs around natural processes and population structures, offer substantive guidance for other salmon recovery efforts. This Article concludes that furthering collaboration between science and policy will play a major role in the success of species conservation programs, but ecosystem-scale experimentation is a puzzle that still needs a solution. C1 Natl Marine Fisheries Serv, Portland, OR USA. RP Volkman, JM (reprint author), Natl Marine Fisheries Serv, Portland, OR USA. NR 95 TC 9 Z9 9 U1 1 U2 4 PU UNIV WASHINGTON SCHOOL OF LAW PI SEATTLE PA WASHINGTON LAW REVIEW 1100 NE CAMPUS PARKWAY 410 CONDON HALL, SEATTLE, WA 98105 USA SN 0043-0617 J9 WASH LAW REV JI Wash. Law Rev. PD JUL PY 1999 VL 74 IS 3 BP 719 EP 762 PG 44 WC Law SC Government & Law GA 235UM UT WOS:000082561000005 ER PT J AU Serreze, MC Clark, MP Armstrong, RL McGinnis, DA Pulwarty, RS AF Serreze, MC Clark, MP Armstrong, RL McGinnis, DA Pulwarty, RS TI Characteristics of the western United States snowpack from snowpack telemetry (SNOTEL) data SO WATER RESOURCES RESEARCH LA English DT Article ID CLIMATE; PRECIPITATION; VARIABILITY; PATTERNS; ACCUMULATION; SEASONALITY; SENSITIVITY; STREAMFLOW; SOUTHWEST; WINTER AB Daily station data from U.S. Department of Agriculture snowpack telemetry (SNOTEL) archives through the 1995/1996 season are used to examine the climatic characteristics of snow water equivalent (SWE) for the mountainous western United States and linkages with precipitation (PRE) and temperature. Quality control procedures were developed to screen outliers in each variable. SWE for April 1 at the SNOTEL sites compares favorably with colocated snow course values. Regional differences in the seasonal cycle of SWE are discussed in terms of winter-half precipitation, temperature, and the corresponding SWE/PRE ratio. The percentage of annual precipitation represented by snowfall is highest for the Sierra Nevada (67%), northwestern Wyoming (64%), Colorado (63%), and Idaho/western Montana (62%) sectors, manifesting high SWE/PRE ratios and winter-half precipitation maxima. Lower percentages for the Pacific Northwest (50%) and Arizona/New Mexico (39%) reflect lower ratios and, especially for the latter region, a larger fraction of PRE falling outside of the accumulation season. Interannual variability in SWE in the colder inland regions is primarily controlled by available precipitation. For the warmer Pacific coast regions and Arizona/New Mexico the more important factor is the SWE/PRE ratio, illustrating the sensitivity of these areas to climate change. C1 Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. Univ Iowa, Dept Geog, Iowa City, IA 52242 USA. NOAA, Off Global Programs, Program Reg Integrated Assessments, Silver Spring, MD 20910 USA. RP Serreze, MC (reprint author), Univ Colorado, Cooperat Inst Res Environm Sci, Campus Box 449, Boulder, CO 80309 USA. RI Clark, Martyn/A-5560-2015 OI Clark, Martyn/0000-0002-2186-2625 NR 32 TC 242 Z9 242 U1 1 U2 86 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0043-1397 J9 WATER RESOUR RES JI Water Resour. Res. PD JUL PY 1999 VL 35 IS 7 BP 2145 EP 2160 DI 10.1029/1999WR900090 PG 16 WC Environmental Sciences; Limnology; Water Resources SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Water Resources GA 211DV UT WOS:000081145400016 ER PT J AU Fuks, IM Tatarskii, VI Barrick, DE AF Fuks, IM Tatarskii, VI Barrick, DE TI Behaviour of scattering from a rough surface at small grazing angles SO WAVES IN RANDOM MEDIA LA English DT Article ID ELECTROMAGNETIC-WAVES; VHF PROPAGATION; SEA; HF AB The particular problem of wave scattering at low grazing angles is of great interest because of its importance for the long-distance propagation of radio waves along the Earth's surface, radar observation of near surface objects, as well as solving many other fundamental and applied problems of remote sensing. One of the main questions is: how do the scattering amplitude and specific cross section behave for extremely small grazing angles? We consider the process of wave scattering by a statistically rough surface with the Neumann boundary condition. This model corresponds to sound scattering from a perfectly 'hard' surface (for example, the interface between air and the sea surface) or 'vertically' polarized electromagnetic waves scattered by a perfectly conducting one-dimensional (i.e. cylindrical) surface when the magnetic field vector is directed along the generating line of this cylindrical surface. We assume that the surface roughness is sufficiently small (in the sense of the Rayleigh parameter) and the surface is rigorously statistically homogeneous and therefore, infinite. We confine ourselves only to the first-order approximation of small perturbation theory and therefore consider every act of wave scattering in the Born approximation when the Bragg scattering process takes place. Only one resonant Fourier component of surface roughness is responsible for the scattering in a given direction; However, we take into account the attenuation of incident and scattered waves due to the multiple scattering processes on the path 'before' and 'after' a scattering event in a given direction. Also we consider every one of these multiple scattering events only in the Born approximation. The main result we have obtained is that for small grazing angles the scattering cross section of the diffuse component decreases as the second power of the grazing angles with respect to the incident and scattered directions, and as the fourth power of the grazing angle for the backscattering (radar) situation. Generalizing our results from plane-wave scattering to finite beams allows us to obtain the criterion on the beamwidth. For sufficiently narrow beams the multiple scattering processes do not play any role because of a short 'interaction path', and only single Bragg scattering determines the scattering amplitude (which does not tend to zero for small grazing angles). However, for sufficiently wide beams the result obtained for infinite plane waves becomes valid: due to the above-mentioned multiple scattering processes, the scattering amplitude tends to zero for small grazing angles. Consequently, the behaviour of the scattering cross section for small grazing angles depends on the radiation pattern width of the transmitting and receiving antennae: for sufficiently wide beams the scattering cross section decreases to zero at small grazing angles, but for narrow beams it tends to the finite non-zero value. C1 Univ Colorado, NOAA, Environm Technol Lab, Cooperat Inst Res Environm Sci, Boulder, CO 80303 USA. CODAR Ocean Sensors, Los Altos, CA 94024 USA. RP Fuks, IM (reprint author), Univ Colorado, NOAA, Environm Technol Lab, Cooperat Inst Res Environm Sci, 325 Broadway, Boulder, CO 80303 USA. NR 32 TC 13 Z9 13 U1 1 U2 2 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0959-7174 J9 WAVE RANDOM MEDIA JI Waves Random Media PD JUL PY 1999 VL 9 IS 3 BP 295 EP 305 DI 10.1088/0959-7174/9/3/302 PG 11 WC Physics, Multidisciplinary SC Physics GA 220WW UT WOS:000081692100002 ER PT J AU Hubbell, JH AF Hubbell, JH TI Compilation of photon cross-sections: Some historical remarks and current status SO X-RAY SPECTROMETRY LA English DT Article; Proceedings Paper CT European Conference on Energy Dispersive X-Ray Spectrometry 1998 (EDXRS-98) CY JUN 07-12, 1998 CL BOLOGNA, ITALY ID RAY ATTENUATION COEFFICIENTS; ENERGY-ABSORPTION COEFFICIENTS; ATOMIC FORM-FACTORS; X-RAY; COMPTON-SCATTERING; PAIR PRODUCTION; INTERNATIONAL-UNION; RAYLEIGH-SCATTERING; MASS ATTENUATION; BOUND ELECTRONS AB In x-ray diffraction spectrometry as well as in the many other scientific, engineering and medical disciplines involving photon radiation, x-ray attenuation coefficients are required as input data. Within a very few years after the discovery of x-rays by Rontgen in 1895, the transmission of a narrow (parallel) beam of x-rays through layers of different materials was measured and quantified with respect to photon (x-ray) energy and atomic number of the material by Barkla and Sadler in 1907. This quantification is in terms of the mass attenuation (or absorption) coefficient mu/rho (cm(2) g(-1)) which for monoenergetic photons can be defined as mu/rho = x(-1) ln(I-0/I), or I/I-0 = exp[-(mu/rho)x] in which x is the mass thickness of the layer in units of g cm(-2), I-0 is the intensity (e.g. photons cm(-2) s(-1)) of the incident beam, I is the intensity of the transmitted beam (measured with the layer interposed), rho is the density of the layer in g cm(-3) and mu is the linear attenuation (or absorption, mu*) coefficient in cm(-1). Current compilations of mu/rho are derived from theoretical or semi-empirical values of the most-probable individual processes according to mu/rho = (sigma(pe) + sigma(incoh) + sigma(coh) + sigma(pair) + sigma(trip))/uA in which sigma(pe) is the atomic photoeffect cross-section, sigma(incoh) and sigma(coh) are the incoherent (Compton) and coherent (Rayleigh) scattering cross-sections, respectively, sigma(pair) and sigma(trip) are the cross-sections for electron-positron pair production (creation) in the field of the nucleus and in the field of the atomic electrons ('triplet' production), respectively, and the factor 1/uA, where u is the atomic mass unit and A is the relative atomic mass of the target element, converts the sigma(i) units from cm(2) per atom to cm(2) g(-1). Since sigma(pair) and sigma(trip) have thresholds above 1 MeV, these do not affect the XRS photon energy region, nor does the photonuclear cross-section sigma(ph.n.) which has threshold of 5 MeV or higher and is not included in current mu/rho compilations. In this brief and arbitrarily selective review, a historical account is given of the evolving compilations of mu/rho from Barkla and Sadler's work at the beginning of this century, up to the NIST and Livermore compilations as this century comes to its close. For the latter compilations of mu/rho, some rough estimates of the 'envelope of uncertainty' in different ranges of photon energy are given. Copyright (C) 1999 John Wiley & Sons, Ltd. C1 Natl Inst Stand & Technol, Ionizing Radiat Div, Gaithersburg, MD 20899 USA. RP Natl Inst Stand & Technol, Ionizing Radiat Div, Gaithersburg, MD 20899 USA. NR 154 TC 24 Z9 25 U1 0 U2 6 PU WILEY-BLACKWELL PI HOBOKEN PA 111 RIVER ST, HOBOKEN 07030-5774, NJ USA SN 0049-8246 EI 1097-4539 J9 X-RAY SPECTROM JI X-Ray Spectrom. PD JUL-AUG PY 1999 VL 28 IS 4 BP 215 EP 223 DI 10.1002/(SICI)1097-4539(199907/08)28:4<215::AID-XRS336>3.0.CO;2-5 PG 9 WC Spectroscopy SC Spectroscopy GA 220XH UT WOS:000081693400003 ER PT J AU Refstie, S Svihus, B Shearer, KD Storebakken, T AF Refstie, S Svihus, B Shearer, KD Storebakken, T TI Nutrient digestibility in Atlantic salmon and broiler chickens related to viscosity and non-starch polysaccharide content in different soyabean products SO ANIMAL FEED SCIENCE AND TECHNOLOGY LA English DT Article DE fish; Salmo salar; chicken; soyabean protein; dietary fibre; digestibility; viscosity ID TROUT ONCORHYNCHUS-MYKISS; 4 SOYBEAN PRODUCTS; RAINBOW-TROUT; GUAR GUM; PHYTIC ACID; GASTROINTESTINAL-TRACT; INTESTINAL VISCOSITY; PLASMA-CHOLESTEROL; NUTRITIONAL-VALUE; SOY-PROTEIN AB Total tract digestibility in Atlantic salmon and ileal digestibility in chicken were assessed from diets with different soyabean products (hulled, toasted, extracted, SBM; reduced oligosaccharide content, ROM; ethanol-extracted protein concentrate, SPC; isolated protein, ISP). The concentration of dietary fibre was highest in SBM and ROM, while it was low in ISP. In vitro viscosity was also higher in SBM than in the other soyabean products. The diets for the salmon and chickens were based on the same feed ingredients, with the exception that fish meal provided half the crude protein in the salmon diets, For each species, the diets were isonitrogenous, contained similar amounts of fat (fish oil), and were balanced with dextrin, thus substituting soyabean non-starch polysaccharides (NSP) and other non-proteinous components by dextrin. In the salmon, total tract digestibility of nitrogen and dry matter were lower (p < 0.05) with the SBM and ROM diets than with the ISP diet. In the chickens, ileal digestibility of dry matter differed among all treatments (p < 0.05). Digestibility of nitrogen, starch, phosphorus and calcium in the chickens was lower (p < 0.05) with the SBM diet than with the ISP and SPC diets, and fat digestibility was lower (p < 0.05) with the SBM and ROM diets than with the SPC diet. Also, the SBM diet gave lower (p < 0.05) digestibility of nitrogen, phosphorus and calcium than the ROM diet, while the ROM diets gave lower (p < 0.05) digestibilities of nitrogen, fat and starch than the ISP and SPC diets. Intestinal viscosity was higher (p < 0.05) and cholesterol content in the blood was lower (p < 0.05) for the chickens fed the SBM-based diet than those fed the other diets. There was a similar response to the different soy products in salmon and chickens with regard to digestibility of nitrogen and fat (p < 0.05). The negative effects of soyabean meals with a low: protein content could indicate antinutritive effects of NSP fractions in soyabean meal, as indicated by the elevated viscosity and the decrease in blood cholesterol content. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Agr Univ Norway, Dept Anim Sci, N-1432 As Nlh, Norway. AKVAFORSK, Inst Aquaculture Res, N-6600 Sunndalsora, Norway. NOAA, Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, Seattle, WA 98112 USA. RP Svihus, B (reprint author), Agr Univ Norway, Dept Anim Sci, POB 5025, N-1432 As Nlh, Norway. RI storebakken, trond/E-8050-2011 OI storebakken, trond/0000-0002-4525-2098 NR 49 TC 129 Z9 140 U1 0 U2 20 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0377-8401 J9 ANIM FEED SCI TECH JI Anim. Feed Sci. Technol. PD JUN 30 PY 1999 VL 79 IS 4 BP 331 EP 345 DI 10.1016/S0377-8401(99)00026-7 PG 15 WC Agriculture, Dairy & Animal Science SC Agriculture GA 212QX UT WOS:000081228700008 ER PT J AU Thacker, WC AF Thacker, WC TI Principal predictors SO INTERNATIONAL JOURNAL OF CLIMATOLOGY LA English DT Article DE principal predictor analysis; Gulf of St. Lawrence; water circulation ID SOUTHERN OSCILLATION; COMPONENTS; OCEAN AB Principal predictors are linear combinations of variables from one set that efficiently describe the collective variability of those from a second set. Their defining eigenproblem is similar to that of canonical correlation analysis, and when the two sets are taken to be the same, principal predictors reduce to principal components. Within the context of a forecast model for the circulation in the Gulf of St. Lawrence, they are shown to be capable of providing a low-dimensional characterization of high-resolution model dynamics. C1 NOAA, Atlantic Oceanog & Meteorol Lab, Miami, FL 33149 USA. RP Thacker, WC (reprint author), NOAA, Atlantic Oceanog & Meteorol Lab, 4301 Rickenbacker Causeway, Miami, FL 33149 USA. RI Thacker, Carlisle/I-3813-2013 OI Thacker, Carlisle/0000-0002-9285-8826 NR 17 TC 6 Z9 6 U1 0 U2 0 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX PO19 1UD, ENGLAND SN 0899-8418 J9 INT J CLIMATOL JI Int. J. Climatol. PD JUN 30 PY 1999 VL 19 IS 8 BP 821 EP 834 DI 10.1002/(SICI)1097-0088(19990630)19:8<821::AID-JOC390>3.3.CO;2-F PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 215FY UT WOS:000081372300002 ER PT J AU Davico, GE Schwartz, RL Ramond, TM Lineberger, WC AF Davico, GE Schwartz, RL Ramond, TM Lineberger, WC TI Photoelectron spectroscopy of benzoquinonide and dehydrobenzoquinone anions SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID CORRELATED MOLECULAR CALCULATIONS; SINGLET-TRIPLET SPLITTINGS; BENZYNE NEGATIVE-IONS; GAUSSIAN-BASIS SETS; ELECTRON-AFFINITIES; P-BENZOQUINONE; O-BENZYNE AB The 364 nm photoelectron spectra of the dehydrobenzoquinone (1(.-)) and benzoquinonide (2(-)) anions are reported. For 1(.-), the unambiguous assignment of the origin peak yields an electron affinity (EA) of 1.859 +/- 0.005 eV. Several vibrational modes of 1 are also reported. Another minor feature at higher electron binding energy is also observed in the spectrum of 1(.-). This band does not contain any resolvable peaks and only the vertical detachment energy could be obtained. This is the first time dehydrobenzoquinone, the benzyne analogue of p-benzoquinone, is observed and characterized. The photoelectron spectrum of 2- shows no resolvable structure. The origin peak could not be assigned unequivocally because of the small Franck-Condon factor for the 0-0 transition, but an upper value of 2.18 eV for the EA of 2 was obtained. Ab initio calculations are used to help in the interpretation of the spectra and the results are utilized to simulate them. C1 Univ Colorado, JILA, Boulder, CO 80309 USA. Univ Colorado, Dept Chem & Biochem, Boulder, CO 80309 USA. Univ Colorado, Natl Inst Stand & Technol, Boulder, CO 80309 USA. RP Lineberger, WC (reprint author), Univ Colorado, JILA, Boulder, CO 80309 USA. NR 32 TC 15 Z9 15 U1 1 U2 1 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 JUN 30 PY 1999 VL 121 IS 25 BP 6047 EP 6054 DI 10.1021/ja990479z PG 8 WC Chemistry, Multidisciplinary SC Chemistry GA 212KX UT WOS:000081216800025 ER PT J AU Claassen, JH Booth, JC Beall, JA Rudman, DA Vale, LR Ono, RH AF Claassen, JH Booth, JC Beall, JA Rudman, DA Vale, LR Ono, RH TI Nonlinear inductive response of high temperature superconducting films measured by the mutual inductance technique SO APPLIED PHYSICS LETTERS LA English DT Article ID MICROSTRIP RESONATOR; THIN-FILMS; INTERMODULATION AB The dependence of the penetration depth lambda on current density J in an unpatterned superconducting film can be measured with a pair of small coaxial coils positioned on opposite sides of the film. Mutual inductance measurements in this configuration with a direct-current (dc) current component in one of the coils provide a means to determine lambda(J). It is possible to separate out the effects of heating by initially trapping a persistent current in the film. The nonlinear (current-dependent) coefficients of lambda(J) measured by this "dc" technique agree well with those measured by third harmonic generation in coplanar waveguide transmission lines at 5 GHz. This nondestructure technique could be used to screen films before incorporating them into circuits sensitive to nonlinear effects. [S0003-6951(99)03226-X]. C1 USN, Res Lab, Washington, DC 20375 USA. Natl Inst Stand & Technol, Boulder, CO 80303 USA. RP Claassen, JH (reprint author), USN, Res Lab, Washington, DC 20375 USA. NR 11 TC 16 Z9 16 U1 2 U2 5 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD JUN 28 PY 1999 VL 74 IS 26 BP 4023 EP 4025 DI 10.1063/1.123248 PG 3 WC Physics, Applied SC Physics GA 208MB UT WOS:000080994200035 ER PT J AU Chervenak, JA Irwin, KD Grossman, EN Martinis, JM Reintsema, CD Huber, ME AF Chervenak, JA Irwin, KD Grossman, EN Martinis, JM Reintsema, CD Huber, ME TI Superconducting multiplexer for arrays of transition edge sensors SO APPLIED PHYSICS LETTERS LA English DT Article ID ELECTROTHERMAL FEEDBACK AB We report the design and testing of an analog superconducting time-division multiplexer to instrument large format arrays of low-temperature bolometers and microcalorimeters. The circuit is designed to multiplex an array of superconducting quantum interference devices, thereby simplifying wiring and room temperature electronics. We have fabricated a prototype 8x1 multiplexer chip and show a switching rate of 1 MHz. We calculate that a 32x32 array or larger is feasible. (C) 1999 American Institute of Physics. [S0003-6951(99)00826-8]. C1 Natl Inst Stand & Technol, Boulder, CO 80303 USA. Univ Colorado, Denver, CO 80217 USA. RP Chervenak, JA (reprint author), Natl Inst Stand & Technol, 325 Broadway, Boulder, CO 80303 USA. RI Huber, Martin/B-3354-2011 NR 10 TC 204 Z9 204 U1 0 U2 12 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD JUN 28 PY 1999 VL 74 IS 26 BP 4043 EP 4045 DI 10.1063/1.123255 PG 3 WC Physics, Applied SC Physics GA 208MB UT WOS:000080994200042 ER PT J AU Edwards, M Griggs, DA Holman, PL Clark, CW Rolston, SL Phillips, WD AF Edwards, M Griggs, DA Holman, PL Clark, CW Rolston, SL Phillips, WD TI Properties of a Raman atom-laser output coupler SO JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS LA English DT Article ID BOSE-EINSTEIN CONDENSATION; GAS AB We have studied the characteristics of an atom laser created by removing atoms from a Bose-Einstein condensate (BEC) via a two-photon Raman process. In contrast with outcoupling by RF transitions, Raman outcoupling offers spatial selectivity within the condensate and delivers significant momentum transfer to the outcoupled atoms. We develop a version of zero-temperature mean-field theory for BECs which includes the internal state of the atom and the effect of laser fields focused into the cloud. For a model condensate we find that the outcoupled matter wave develops sharp peaks at spatial positions where the two-photon Raman process is resonant with the hyperfine splitting of the atomic ground state. As time proceeds the width of the outcoupled wave expands and a steady stream of matter waves travels outside the condensate volume. C1 Georgia So Univ, Dept Phys, Statesboro, GA 30460 USA. Natl Inst Stand & Technol, Div Electron & Opt Phys, US Dept Commerce, Gaithersburg, MD 20899 USA. Natl Inst Stand & Technol, Atom Phys Div, US Dept Commerce, Gaithersburg, MD 20899 USA. RP Phillips, WD (reprint author), Univ Maryland, Inst Phys Sci & Technol, College Pk, MD 20742 USA. RI Clark, Charles/A-8594-2009; rolston, steven/L-5175-2013 OI Clark, Charles/0000-0001-8724-9885; rolston, steven/0000-0003-1671-4190 NR 26 TC 27 Z9 27 U1 0 U2 2 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0953-4075 J9 J PHYS B-AT MOL OPT JI J. Phys. B-At. Mol. Opt. Phys. PD JUN 28 PY 1999 VL 32 IS 12 BP 2935 EP 2950 DI 10.1088/0953-4075/32/12/312 PG 16 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 214CK UT WOS:000081309900017 ER PT J AU Brewczyk, M Clark, CW Lewenstein, M Rzazewski, K AF Brewczyk, M Clark, CW Lewenstein, M Rzazewski, K TI Non-self-similar modes of vibration of a Bose-Einstein condensate SO JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS LA English DT Letter ID COLLECTIVE EXCITATIONS; NEUTRAL ATOMS; GAS; FIELD; TRAP; TEMPERATURE; DYNAMICS AB A hydrodynamical version of the time-dependent Gross-Pitaevskii equation is used to describe driven vibrations of a Bose-Einstein condensate of (87)Rb atoms in a magnetic trap. If the trap frequency is suddenly decreased, and later is suddenly returned to its initial value, the response of the condensate departs from the sell-similar character that is obtained in the Thomas-Fermi approach. We show that the self-similar Thomas-Fermi modes are, in fact, unstable. Thus, the 'quantum pressure' term in the hydrodynamic equations of motion can play a significant role in condensate excitation dynamics, even when its effect on ground-state properties is negligible. C1 Filia Univ Warszawskiego, PL-15424 Bialystok, Poland. Natl Inst Stand & Technol, US Dept Commerce, Div Electron & Opt Phys, Gaithersburg, MD 20899 USA. CEA Saclay, Serv Photons Atomes & Mol, F-91191 Gif Sur Yvette, France. Polish Acad Sci, Ctr Fizyki Teoretycznej, PL-02668 Warsaw, Poland. Coll Sci, PL-02668 Warsaw, Poland. RP Brewczyk, M (reprint author), Filia Univ Warszawskiego, Ul Lipowa 41, PL-15424 Bialystok, Poland. RI Clark, Charles/A-8594-2009; Rzazewski, Kazimierz/G-4854-2011; Lewenstein, Maciej/I-1337-2014 OI Clark, Charles/0000-0001-8724-9885; Rzazewski, Kazimierz/0000-0002-6082-3565; Lewenstein, Maciej/0000-0002-0210-7800 NR 27 TC 1 Z9 1 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0953-4075 J9 J PHYS B-AT MOL OPT JI J. Phys. B-At. Mol. Opt. Phys. PD JUN 28 PY 1999 VL 32 IS 12 BP L271 EP L278 DI 10.1088/0953-4075/32/12/103 PG 8 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 214CK UT WOS:000081309900003 ER PT J AU Kash, MM Sautenkov, VA Zibrov, AS Hollberg, L Welch, GR Lukin, MD Rostovtsev, Y Fry, ES Scully, MO AF Kash, MM Sautenkov, VA Zibrov, AS Hollberg, L Welch, GR Lukin, MD Rostovtsev, Y Fry, ES Scully, MO TI Ultraslow group velocity and enhanced nonlinear optical effects in a coherently driven hot atomic gas SO PHYSICAL REVIEW LETTERS LA English DT Article ID ELECTROMAGNETICALLY INDUCED TRANSPARENCY; INTERFERENCE AB We report the observation of small group velocities of order 90 m/s and large group delays of greater than 0.26 ms, in an optically dense hot rubidium gas (approximate to 360 K). Media of this kind yield strong nonlinear interactions between very weak optical fields and very sharp spectral features. The result is in agreement with previous studies on nonlinear spectroscopy of dense coherent media. C1 Texas A&M Univ, Dept Phys, College Stn, TX 77843 USA. Max Planck Inst Quantenopt, D-85748 Garching, Germany. Natl Inst Stand & Technol, Boulder, CO 80303 USA. Harvard Smithsonian Ctr Astrophys, ITAMP, Cambridge, MA 02138 USA. Lake Forest Coll, Dept Phys, Lake Forest, IL 60045 USA. RP Kash, MM (reprint author), Texas A&M Univ, Dept Phys, College Stn, TX 77843 USA. RI Sautenkov, Vladimir/N-7024-2013; Fry, Edward/B-6012-2016; Zibrov, Alexander/G-7419-2014 OI Sautenkov, Vladimir/0000-0001-8400-9405; NR 16 TC 963 Z9 988 U1 4 U2 45 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD JUN 28 PY 1999 VL 82 IS 26 BP 5229 EP 5232 DI 10.1103/PhysRevLett.82.5229 PG 4 WC Physics, Multidisciplinary SC Physics GA 211GN UT WOS:000081152700013 ER PT J AU Zimmerli, GA Wilkinson, RA Ferrell, RA Moldover, MR AF Zimmerli, GA Wilkinson, RA Ferrell, RA Moldover, MR TI Electrostriction of near-critical SF6 in microgravity SO PHYSICAL REVIEW LETTERS LA English DT Article ID LIQUID CRITICAL-POINT; DIELECTRIC-CONSTANT AB We used interferometry to measure the electric-field-induced (i.e., "electrostrictive") increase of the density of sulfur hexafluoride near its critical point. The results at the temperatures T-c + 5 mK, T-c + 10 mK, and T-c + 30 mK, with T-c = 319 K, agree with a calculation based on the Clausius-Mossotti relation and the restricted cubic model equation of state. These measurements were performed in microgravity so that the electrostrictive density changes (less than or equal to 3.5% in this work) would not be complicated by stratification of the fluid's density induced by the Earth's gravity. C1 Natl Ctr Micrograv Res, Cleveland, OH 44135 USA. NASA, Lewis Res Ctr, Micrograv Sci Div, Cleveland, OH 44135 USA. Univ Maryland, Dept Phys, College Pk, MD 20742 USA. NIST, Phys & Chem Properties Div, Bethesda, MD 20892 USA. RP Zimmerli, GA (reprint author), Natl Ctr Micrograv Res, Cleveland, OH 44135 USA. RI Moldover, Michael/E-6384-2013 NR 16 TC 8 Z9 8 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 JUN 28 PY 1999 VL 82 IS 26 BP 5253 EP 5256 DI 10.1103/PhysRevLett.82.5253 PG 4 WC Physics, Multidisciplinary SC Physics GA 211GN UT WOS:000081152700019 ER PT J AU Hobbie, EK Migler, KB AF Hobbie, EK Migler, KB TI Vorticity elongation in polymeric emulsions SO PHYSICAL REVIEW LETTERS LA English DT Article ID SHEAR-FLOW; DROP DEFORMATION; PHASE; BREAKUP; FLUIDS; FLUCTUATIONS; STABILITY; PATTERN; STEADY; BLENDS AB Video microscopy is used to measure the shear-induced deformation of dilute emulsions composed of viscoelastic polymer melts. In the limit of strong shear, a transition in which the droplets elongate perpendicular to the flow field is observed. A force-balance argument relates this behavior to the change in first normal stress difference across the droplet interface. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Hobbie, EK (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RI Hobbie, Erik/C-8269-2013 NR 27 TC 45 Z9 45 U1 1 U2 9 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 28 PY 1999 VL 82 IS 26 BP 5393 EP 5396 DI 10.1103/PhysRevLett.82.5393 PG 4 WC Physics, Multidisciplinary SC Physics GA 211GN UT WOS:000081152700054 ER PT J AU Cole, JE Rind, D Webb, RS Jouzel, J Healy, R AF Cole, JE Rind, D Webb, RS Jouzel, J Healy, R TI Climatic controls on interannual variability of precipitation delta O-18: Simulated influence of temperature, precipitation amount, and vapor source region SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID GENERAL-CIRCULATION MODEL; ISOTOPE COMPOSITION; WATER ISOTOPES; AMAZON BASIN; ICE CORES; GREENLAND; CYCLES; TRENDS; SNOW; HDO AB We use an atmospheric GCM that incorporates stable isotopes and regional vapor source tracers in the hydrologic cycle to explore the relationship between interannual variability in climate and precipitation delta(18)O globally. On the basis of a 12-year simulation forced by observed sea surface temperatures (SSTs), we identify changes in the amount of precipitation and in the contributions of local and nearby vapor sources as the most important determinants of simulated interannual isotopic changes. The model simulates weak positive correlation between temperature and isotopic variability only in certain continental regions, mostly in the extratropics. Comparison with long observed records of isotopes and climate indicates that the model simulates realistic patterns of temperature-isotope correlation but may overestimate the isotopic influence of precipitation amount. perturbations in circulation patterns that alter the transport and mixing of air masses at a site also change the relative contributions of vapor from different source regions. Simulated changes in vapor source regions are large, reaching +/- 10-15% of the total precipitation, and cause significant isotopic variability in nearly all grid cells. Our results suggest that shifts among vapor sources may provide an important control on the interannual isotopic variability observed in modern precipitation and paleoclimatic records. The isotopic variability simulated in this experiment results from the interaction of several aspects of climate. Interannual temperature variability generally involves circulation changes that alter air mass transport, vapor source regions, and condensation history; this advective mechanism may explain the relative weakness of temperature-isotope correlations in both the model and the observations. C1 Univ Colorado, Boulder, CO 80309 USA. NASA, Goddard Inst Space Studies, New York, NY 10025 USA. NOAA, NGDC Paleoclimatol, Boulder, CO 80303 USA. CEA Saclay, CEA, UMR CNRS 1572, Lab Sci Climat & Environm, F-91191 Gif Sur Yvette, France. Woods Hole Oceanog Inst, Woods Hole, MA 02543 USA. RP Cole, JE (reprint author), Univ Colorado, Campus Box 450, Boulder, CO 80309 USA. EM coleje@spot.colorado.edu; drind@giss.nasa.gov; rsw@ngdc.noaa.gov; jouzel@obelix.saclay.cea.fr; rhealy@whoi.edu RI Healy, Richard/J-9214-2015 OI Healy, Richard/0000-0002-5098-8921 NR 47 TC 72 Z9 74 U1 2 U2 14 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 27 PY 1999 VL 104 IS D12 BP 14223 EP 14235 DI 10.1029/1999JD900182 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 211XW UT WOS:000081188000004 ER PT J AU Gloor, M Fan, SM Pacala, S Sarmiento, J Ramonet, M AF Gloor, M Fan, SM Pacala, S Sarmiento, J Ramonet, M TI A model-based evaluation of inversions of atmospheric transport, using annual mean mixing ratios, as a tool to monitor fluxes of nonreactive trace substances like CO2 on a continental scale SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID GENERAL CIRCULATION MODEL; CARBON-DIOXIDE DATA; BUDGET; SIMULATION; RECORD AB The inversion of atmospheric transport of CO2 may potentially be a means for monitoring compliance with emission treaties in the future. There are two types of errors, though, which may cause errors in inversions: (1) amplification of high-frequency data variability given the information loss in the atmosphere by mixing and (2) systematic errors in the CO2 flux estimates caused by various approximations used to formulate the inversions. In this study we use simulations with atmospheric transport models and a time independent inverse scheme to estimate these errors as a function of network size and the number of flux regions solved for. Our main results are as follows. (1) When solving for 10-20 source regions, the average uncertainty of flux estimates caused by amplification of high-frequency data variability alone decreases strongly with increasing number of stations for up to similar to 150 randomly positioned stations and then levels off (for 150 stations of the order of +/-0.2 Pg C yr(-1)). As a rule of thumb, about 10 observing stations are needed per region to be estimated. (2) Of all the sources of systematic errors, modeling error is the largest. Our estimates of SF6 emissions from five continental regions simulated with 12 different AGCMs differ by up to a factor of 2. The number of observations needed to overcome the information loss due to atmospheric mixing is hence small enough to permit monitoring of fluxes with inversions on a continental scale in principle. Nevertheless errors in transport modeling are still too large for inversions to be a quantitatively reliable option for flux monitoring. C1 Princeton Univ, Dept Ecol & Evolutionary Biol, Princeton, NJ 08544 USA. Princeton Univ, Carbon Modeling Consortium, Atmospher & Ocean Sci Program, Princeton, NJ 08544 USA. RP Gloor, M (reprint author), Princeton Univ, Dept Ecol & Evolutionary Biol, Sayre Hall,Forrestal Campus, Princeton, NJ 08544 USA. NR 35 TC 29 Z9 29 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUN 27 PY 1999 VL 104 IS D12 BP 14245 EP 14260 DI 10.1029/1999JD900132 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 211XW UT WOS:000081188000006 ER PT J AU Butler, JH Battle, M Bender, ML Montzka, SA Clarke, AD Saltzman, ES Sucher, CM Severinghaus, JP Elkins, JW AF Butler, JH Battle, M Bender, ML Montzka, SA Clarke, AD Saltzman, ES Sucher, CM Severinghaus, JP Elkins, JW TI A record of atmospheric halocarbons during the twentieth century from polar firn air SO NATURE LA English DT Article ID LIFETIME EXPERIMENT; METHYL-CHLORIDE; EMISSIONS; TRENDS; SF6; CHLOROFLUOROCARBONS; UNCERTAINTIES; DISTRIBUTIONS; HYDROCARBONS; ABUNDANCE AB Measurements of trace gases in air trapped in polar firn (unconsolidated snow) demonstrate that natural sources of chlorofluorocarbons, halons, persistent chlorocarbon solvents and sulphur hexafluoride to the atmosphere are minimal or non-existent. Atmospheric concentrations of these gases, reconstructed back to the late nineteenth century, are consistent with atmospheric histories derived from anthropogenic emission rates and known atmospheric lifetimes. The measurements confirm the predominance of human activity in the atmospheric budget of organic chlorine, and allow the estimation of atmospheric histories of halogenated gases of combined anthropogenic and natural origin. The pre-twentieth-century burden of methyl chloride was close to that at present, while the burden of methyl bromide was probably over half of today's value. C1 NOAA, Climate Monitoring & Diagnost Lab, Boulder, CO 80303 USA. Univ Rhode Isl, Grad Sch Oceanog, Narragansett, RI 02882 USA. Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. Univ Miami, Rosenstiel Sch Marine & Atmospher Sci, Miami, FL 33149 USA. RP Butler, JH (reprint author), NOAA, Climate Monitoring & Diagnost Lab, Boulder, CO 80303 USA. OI Montzka, Stephen/0000-0002-9396-0400 NR 52 TC 156 Z9 169 U1 3 U2 22 PU MACMILLAN MAGAZINES LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD JUN 24 PY 1999 VL 399 IS 6738 BP 749 EP 755 DI 10.1038/21586 PG 7 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 210JP UT WOS:000081101600044 ER PT J AU Ortigoso, J Kleiner, I Hougen, JT AF Ortigoso, J Kleiner, I Hougen, JT TI The K-rotational labeling problem for eigenvectors from internal rotor calculations: Application to energy levels of acetaldehyde below the barrier SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID POLYATOMIC-MOLECULES; MODEL; MILLIMETER; SURFACES; SPECTRUM; STATES AB The problem of attaching K rotational quantum number labels to computer-generated numerical eigenvectors with extensive basis set mixing is considered for the internal-rotationoverall-rotation problem in molecules with one methyl top. Quantum number labeling problems arise physically because the torsional and the rotational degrees of freedom both pass from one limiting case to another as the torsional energy moves from below the top of the internal rotation barrier to above it, i.e., the torsional degree of freedom changes from a vibration to an internal rotation, while the rotational degree of freedom moves its direction of quantization from a principal axis to an axis depending also on angular momentum generated by the methyl top rotation. Since the choice of axis system, basis set, and computational scheme all influence the eigenfunction labeling procedure, consideration is limited to a commonly used two-step matrix-diagonalization scheme and to acetaldehyde as a numerical example. Torsional labels upsilon(t)=0, 1, and 2 for eigenfunctions generated in the first diagonalization step are assigned in order of increasing eigenvalues, and rotational energy surfaces are constructed for the A and E symmetry components of these three torsional states. Projections of rotational eigenvectors over angular momentum coherent states are used to show that classical trajectories on the appropriate rotational energy surface give faithful representations of the quantum wave functions. Irregularities in the rotational energy level structure within a given torsional state can then be understood in terms of extra separatrices in the classical phase space and unusual wave function densities in the coherent state projections. Results are used to devise an automatic K labeling scheme for numerically obtained torsion-rotation levels belonging to torsional states below the top of the internal rotation barrier. (C) 1999 American Institute of Physics. [S0021-9606(99)00823-5]. C1 CSIC, Inst Estructura Mat, Madrid, Spain. Univ Paris 11, Photophys Mol Lab, F-94105 Orsay, France. NIST, Opt Technol Div, Gaithersburg, MD 20899 USA. RP Ortigoso, J (reprint author), CSIC, Inst Estructura Mat, Serrano 121, Madrid, Spain. RI Ortigoso, Juan/F-1234-2016 NR 22 TC 9 Z9 9 U1 0 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD JUN 22 PY 1999 VL 110 IS 24 BP 11688 EP 11699 DI 10.1063/1.479115 PG 12 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 204CN UT WOS:000080745500004 ER PT J AU Feder, DL Clark, CW Schneider, BI AF Feder, DL Clark, CW Schneider, BI TI Vortex stability of interacting Bose-Einstein condensates confined in anisotropic harmonic traps SO PHYSICAL REVIEW LETTERS LA English DT Article ID COLLECTIVE EXCITATIONS; GAS; VORTICES; ROTATION AB Vortex states of weakly interacting Bose-Einstein condensates confined in three-dimensional rotating harmonic traps are investigated numerically at zero temperature. The ground state in the rotating frame is obtained by propagating the Gross-Pitaevskii equation for the condensate in imaginary time. The total energies between states with and without a vortex are compared, yielding critical rotation frequencies that depend on the anisotropy of the trap and the number of atoms. Vortices displaced from the center of nonrotating traps are found to have long lifetimes for sufficiently large numbers of atoms. The relationship between vortex stability and bound core states is explored. C1 Univ Oxford, Oxford OX1 3PU, England. NIST, Div Electron & Opt Phys, Technol Adm, US Dept Commerce, Gaithersburg, MD 20899 USA. Natl Sci Fdn, Div Phys, Arlington, VA 22230 USA. RP Feder, DL (reprint author), Univ Oxford, Parks Rd, Oxford OX1 3PU, England. RI Clark, Charles/A-8594-2009 OI Clark, Charles/0000-0001-8724-9885 NR 39 TC 114 Z9 114 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 JUN 21 PY 1999 VL 82 IS 25 BP 4956 EP 4959 DI 10.1103/PhysRevLett.82.4956 PG 4 WC Physics, Multidisciplinary SC Physics GA 207XP UT WOS:000080961300002 ER PT J AU Donati, C Glotzer, SC Poole, PH AF Donati, C Glotzer, SC Poole, PH TI Growing spatial correlations of particle displacements in a simulated liquid on cooling toward the glass transition SO PHYSICAL REVIEW LETTERS LA English DT Article ID SUPERCOOLED LIQUIDS; LENGTH SCALE; DYNAMICS; HETEROGENEITIES; RELAXATION; BEHAVIOR; MIXTURE; MOTION AB We define a correlation function that quantifies the spatial correlation of single-particle displacements in liquids and amorphous materials. We show that for an equilibrium liquid this function is related to fluctuations in a bulk dynamical variable. We evaluate this function using computer simulations of an equilibrium glass-forming liquid, and show that long range spatial correlations of displacements emerge and grow on cooling toward the mode coupling critical temperature. C1 Natl Inst Stand & Technol, Div Polymers, Gaithersburg, MD 20899 USA. Natl Inst Stand & Technol, Ctr Theret & Computat Mat Sci, Gaithersburg, MD 20899 USA. Univ Western Ontario, Dept Math Appl, London, ON N6A 5B7, Canada. RP Donati, C (reprint author), Natl Inst Stand & Technol, Div Polymers, Gaithersburg, MD 20899 USA. RI Poole, Peter/C-7943-2009; Donati, Claudio/J-5180-2012; OI Poole, Peter/0000-0001-5985-0585; Donati, Claudio/0000-0001-8688-1651 NR 26 TC 128 Z9 128 U1 0 U2 8 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 21 PY 1999 VL 82 IS 25 BP 5064 EP 5067 DI 10.1103/PhysRevLett.82.5064 PG 4 WC Physics, Multidisciplinary SC Physics GA 207XP UT WOS:000080961300029 ER PT J AU van Zee, RD Hodges, JT Looney, JP AF van Zee, RD Hodges, JT Looney, JP TI Pulsed, single-mode cavity ringdown spectroscopy SO APPLIED OPTICS LA English DT Article ID OPTICAL PARAMETRIC OSCILLATOR; DOWN SPECTROSCOPY; ABSORPTION-SPECTROSCOPY; HETERODYNE-DETECTION; OXYGEN; STABILIZATION; SPECTROMETER; STRENGTHS; BANDS; H-2 AB We discuss the use of single-mode cavity ringdown spectroscopy with pulsed lasers for quantitative gas density and line strength measurements. The single-mode approach to cavity ringdown spectroscopy gives single exponential decay signals without mode beating, which allows measurements with uncertainties near the shot-noise Limit. The technique is demonstrated with a 10-cm-long ringdown cavity and a pulsed, frequency-stabilized optical parametric oscillator as the light source. A noise-equivalent absorption coefficient of 5 x 10(-10) cm(-1) Hz(-1/2) is demonstrated, and the relative standard deviation in the ringdown time (sigma(tau)/tau) extracted from a fit to an individual ringdown curve is found to be the same as that for an ensemble of hundreds of independent measurements. Repeated measurement of a Line strength is shown to have a standard deviation <0.3%. The effects of normally distributed noise on quantities measured using cavity ringdown spectroscopy are discussed, formulas for the relative standard deviation in the ringdown time are given in the shot- and technical-noise limits, and the noise-equivalent absorption coefficient in these limits are compared for pulsed and continuous-wave Light sources. C1 Natl Inst Stand & Technol, Chem Sci & Technol Lab, Gaithersburg, MD 20899 USA. RP van Zee, RD (reprint author), Natl Inst Stand & Technol, Chem Sci & Technol Lab, 100 Bur Dr, Gaithersburg, MD 20899 USA. RI Hodges, Joseph/B-4578-2009 NR 37 TC 76 Z9 76 U1 2 U2 24 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 1999 VL 38 IS 18 BP 3951 EP 3960 DI 10.1364/AO.38.003951 PG 10 WC Optics SC Optics GA 208FA UT WOS:000080978900015 PM 18320004 ER PT J AU Longfellow, CA Ravishankara, AR Hanson, DR AF Longfellow, CA Ravishankara, AR Hanson, DR TI Reactive uptake on hydrocarbon soot: Focus on NO2 SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID BLACK CARBON SOOT; NITROUS-ACID; AMORPHOUS-CARBON; HETEROGENEOUS INTERACTION; LOWER STRATOSPHERE; CHEMICAL-KINETICS; UPPER TROPOSPHERE; SULFURIC-ACID; SURFACES; AEROSOLS AB The heterogeneous reactivity of NO2 with soot, two combustion products typically produced in close proximity, may have significant implications for the chemistry occurring in the atmosphere, especially the urban troposphere. As the soot produced in the environment is not well characterized, the interaction of NO2 with a number of different types of laboratory-generated soot was studied. The production of HONO was observed in the interaction of NO2 with methane, propane, hexane, and kerosene soot. It was found that soot produced from hydrocarbons catalyzed the reaction of NO2 with H2O to give MONO. Reactive uptake coefficients for this process that are measured in the laboratory may not be easily applied to atmospheric calculations without more information. C1 NOAA, Aeron Lab, Boulder, CO 80303 USA. Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. Univ Colorado, Dept Chem & Biochem, Boulder, CO 80309 USA. RP Longfellow, CA (reprint author), NOAA, Aeron Lab, 325 Broadway, Boulder, CO 80303 USA. RI Ravishankara, Akkihebbal/A-2914-2011 NR 41 TC 75 Z9 77 U1 1 U2 12 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUN 20 PY 1999 VL 104 IS D11 BP 13833 EP 13840 DI 10.1029/1999JD900145 PG 8 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 207BL UT WOS:000080915400009 ER PT J AU de Laat, ATJ Zachariasse, M Roelofs, GJ van Velthoven, P Dickerson, RR Rhoads, KP Oltmans, SJ Lelieveld, J AF de Laat, ATJ Zachariasse, M Roelofs, GJ van Velthoven, P Dickerson, RR Rhoads, KP Oltmans, SJ Lelieveld, J TI Tropospheric O-3 distribution over the Indian Ocean during spring 1995 evaluated with a chemistry-climate model SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID GENERAL-CIRCULATION MODEL; MARINE BOUNDARY-LAYER; DRY DEPOSITION PARAMETERIZATION; DYNAMIC-INITIALIZATION; OZONE; PACIFIC; ATMOSPHERE; TRANSPORTS; TROPICS; AEROSOL AB An analysis of tropospheric O-3 over the Indian Ocean during spring 1995 is presented based on O-3 soundings and results from the European Centre Hamburg (ECHAM) chemistry-general circulation model. The ECHAM model is nudged toward actual meteorology using European Centre for Medium-Range Weather Forecasts analyses, to enable a direct comparison between model results and in situ observations. The model reproduces observed CO levels in different air mass categories. The model also reproduces the general tendencies and the diurnal variation in the observed surface pressure, although the amplitude of the diurnal variation in the amplitude is underestimated. The model simulates the general O-3 tendencies as seen in the sonde observations. Tropospheric O-3 profiles were characterized by low surface concentrations (<10 ppbv), midtropospheric maxima (60-100 ppbv, at 700-250 hPa) and upper tropospheric minima (<20 ppbv, at 250-100 hPa). Large-scale upper tropospheric O-3 minima were caused by convective transport of O-3-depleted boundary layer air in the intertropical convergence zone (ITCZ). Similarly, an upper tropospheric O-3 minimum was caused by Cyclone Marlene south of the ITCZ. The midtropospheric O-3 maxima were caused by transport of polluted African air. The ECHAM model appears to overestimate surface O-3 levels and does not reproduce the diurnal variations very well. This could be related to unaccounted multiphase O-3 destruction mechanisms involving low level clouds and aerosols, and missing halogen chemistry. C1 Univ Utrecht, Inst Marine & Atmospher Res, NL-3584 CC Utrecht, Netherlands. Royal Netherlands Meteorol Inst, NL-3730 AE De Bilt, Netherlands. Univ Maryland, Dept Meteorol, College Pk, MD 20742 USA. Univ Maryland, Ctr Clouds Chem & Climate, College Pk, MD 20742 USA. Univ Delaware, Dept Chem, Newark, DE 19711 USA. NOAA, Climate Monitoring & Diagnost Lab, RECG, Boulder, CO 80303 USA. RP de Laat, ATJ (reprint author), Univ Utrecht, Inst Marine & Atmospher Res, Princetonplein 5, NL-3584 CC Utrecht, Netherlands. EM a.t.j.laat@phys.uu.nl RI Dickerson, Russell/F-2857-2010; Lelieveld, Johannes/A-1986-2013 OI Dickerson, Russell/0000-0003-0206-3083; NR 51 TC 42 Z9 42 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 20 PY 1999 VL 104 IS D11 BP 13881 EP 13893 DI 10.1029/1999JD900176 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 207BL UT WOS:000080915400013 ER PT J AU Tyler, SC Ajie, HO Gupta, ML Cicerone, RJ Blake, DR Dlugokencky, EJ AF Tyler, SC Ajie, HO Gupta, ML Cicerone, RJ Blake, DR Dlugokencky, EJ TI Stable carbon isotopic composition of atmospheric methane: A comparison of surface level and free tropospheric air SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID PEM-WEST-A; SOUTHERN-HEMISPHERE; RICE PADDIES; GROWTH-RATE; NASA DC-8; CH4; OXIDATION; MONOXIDE; FRACTIONATION; DEUTERIUM AB We report CH4 mixing ratios and delta(13)C of CH4 values for remote air at two groundbased atmospheric sampling sites for the period December 1994 to August 1998 and similar data from aircraft sampling of air masses from near sea level to near tropopause in September and October of 1996 during the Global Tropospheric Experiment Pacific Exploratory Mission (PEM)Tropics A. Surface values of delta(13)C-CH4 ranged from -47.02 to -47.52 parts per thousand at Niwot Ridge, Colorado (40 degrees N, 105 degrees W), and from -46.81 to -47.64 parts per thousand at Montana de Ore, California (35 degrees N, 121 degrees W). Samples for isotopic analysis were taken from 2 degrees to 27 degrees S latitude and 81 degrees to 158 degrees W longitude and from sea level to 11.3 km in altitude during the PEM-Tropics A mission. They represent the first study of (CH4)-C-13 in the tropical free troposphere. At similar to 11 km, delta(13)C-CH4 was similar to 1 parts per thousand greater than surface level values. Methane was generally enriched in C-13 as altitude increased and as latitude increased (toward the South Pole). Using criteria to filter out stratospheric subsidence and convective events on the basis of other trace gases present in the samples, we find evidence of a vertical gradient in delta(13)C-CH4 in the tropical troposphere. The magnitude of the isotopic shifts in atmospheric CH4 with altitude are examined with a two-dimensional tropospheric photochemical model and experimentally determined values for carbon kinetic isotope effects in chemical loss processes of CH4 Model-calculated values for delta(13)C-CH4 in both the troposphere and lower stratosphere significantly underpredict the enrichment in (CH4)-C-13 with altitude observed in our measurement data and data of other research groups. C1 Univ Calif Irvine, Earth Syst Sci Dept, Irvine, CA 92697 USA. Univ Calif Irvine, Dept Chem, Irvine, CA 92697 USA. NOAA, Climate Monitoring & Diagnost Lab, Boulder, CO 80303 USA. RP Tyler, SC (reprint author), Univ Calif Irvine, Earth Syst Sci Dept, Irvine, CA 92697 USA. NR 62 TC 34 Z9 35 U1 0 U2 7 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JUN 20 PY 1999 VL 104 IS D11 BP 13895 EP 13910 DI 10.1029/1999JD900029 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 207BL UT WOS:000080915400014 ER PT J AU Fuselier, SA Lockwood, M Onsager, TG Peterson, WK AF Fuselier, SA Lockwood, M Onsager, TG Peterson, WK TI The source population for the cusp and cleft LLBL for southward IMF SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID PARTICLE-PRECIPITATION CHARACTERISTICS; BOW SHOCK; DAYSIDE IONOSPHERE; MAGNETOSHEATH PLASMA; LOW-ALTITUDES; SOLAR-WIND; MAGNETOSPHERE; MAGNETOPAUSE; IONS; IDENTIFICATION AB The distinction between plasma properties in different dayside regions in the Earth's magnetosphere is of strong interest as it is often indicative of specific physical processes. This is certainly true for the distinction between low latitude boundary layer (LLBL) and cusp plasma, which has been attributed to the effects of plasma diffusion across the magnetopause (LLBL) versus more direct entry of magnetosheath plasma(cusp). It is also the case, however, that quite different plasma regions can result more simply from a common source plasma, and from different stages of temporal evolution of the plasma associated with magnetospheric convection. In this paper, we show that, for southward interplanetary magnetic field (IMF) conditions, the distinction between the cusp and cleft/LLBL at low altitudes may result from;the single process of magnetosheath plasma entry into the magnetosphere on reconnected field lines. The different plasma characteristics of the two regions result from the properties of the source magnetosheath ion distribution and the effects of magnetic reconnection. Using well known properties of the magnetosheath, several predictions concerning the cusp and cleft/ LLBL precipitation are readily derived. C1 Lockheed Martin Adv Technol Ctr, Dept L942, Palo Alto, CA 94304 USA. Rutherford Appleton Lab, Didcot OX11 0QX, Oxon, England. NOAA, Space Environm Ctr, R S SE, Boulder, CO 80303 USA. RP Fuselier, SA (reprint author), Lockheed Martin Adv Technol Ctr, Dept L942, 3251 Hanover St,Bldg 255, Palo Alto, CA 94304 USA. RI Lockwood, Mike/G-1030-2011; Peterson, WK/A-8706-2009 OI Lockwood, Mike/0000-0002-7397-2172; Peterson, WK/0000-0002-1513-6096 NR 24 TC 16 Z9 17 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUN 15 PY 1999 VL 26 IS 12 BP 1665 EP 1668 DI 10.1029/1999GL900354 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 207DT UT WOS:000080920700006 ER PT J AU Dvortsov, VL Geller, MA Solomon, S Schauffler, SM Atlas, EL Blake, DR AF Dvortsov, VL Geller, MA Solomon, S Schauffler, SM Atlas, EL Blake, DR TI Rethinking reactive halogen budgets in the midlatitude lower stratosphere SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID GENERAL-CIRCULATION MODEL; ATMOSPHERIC BROMINE; OZONE; CHEMISTRY; PARAMETERIZATION; SIMULATIONS; SENSITIVITY; CONVECTION; TRANSPORT AB Current stratospheric models have difficulties in fully explaining the observed midlatitude ozone depletion in the lowermost stratosphere, particularly near the tropopause. Such models assume that only long-lived source gases provide significant contributions to the stratospheric halogen budget, while all the short-lived compounds are removed in the troposphere, the products being rained out. Here we show this assumption to be flawed. Using bromine species as an example, we show that in the lowermost stratosphere, where the observed midlatitude ozone trend maximizes, bromoform (CHBr3) alone likely contributes more inorganic bromine than all the conventional long-lived sources (halons and methyl bromide) combined. C1 NOAA, Aeron Lab, Boulder, CO 80303 USA. SUNY Stony Brook, Stony Brook, NY 11794 USA. Natl Ctr Atmospher Res, Boulder, CO 80307 USA. Univ Calif Irvine, Dept Chem, Irvine, CA 92616 USA. Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. RP Dvortsov, VL (reprint author), NOAA, Aeron Lab, 325 Broadway, Boulder, CO 80303 USA. RI Atlas, Elliot/J-8171-2015 NR 25 TC 86 Z9 86 U1 0 U2 13 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 1999 VL 26 IS 12 BP 1699 EP 1702 DI 10.1029/1999GL900309 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 207DT UT WOS:000080920700015 ER PT J AU Shaw, JA Bates, JJ Zorn, HM Churnside, JH AF Shaw, JA Bates, JJ Zorn, HM Churnside, JH TI Observations of downwelling infrared spectral radiance at Mauna Loa, Hawaii during the 1997-1998 ENSO event SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID WATER-VAPOR; ATMOSPHERE AB Measurements of downwelling infrared spectral radiance at Mauna Loa, Hawaii during April and May of 1998 indicate unusually high infrared atmospheric transmittance. This is linked to large-scale drying of the upper troposphere and stratosphere in the subtropical Pacific, which appears to be associated with the extreme El Nino-Southern Oscillation (ENSO) event of 1997-1998. During the driest periods, transmission windows opened in the wavenumber range of 500-600 cm(-1), a water vapor rotational band that normally has high opacity. These data demonstrate the potential value of long-term mountain-top measurements for monitoring upper tropospheric water vapor and for validating satellite measurements of upper-tropospheric water vapor. C1 NOAA, ERL, Environm Technol Lab, Boulder, CO 80303 USA. NOAA, ERL, Climate Diagnost Ctr, Boulder, CO 80303 USA. Cooperat Inst Res Environm Sci, Environm Technol Lab, Boulder, CO 80303 USA. RP Shaw, JA (reprint author), NOAA, ERL, Environm Technol Lab, 325 Broadway,R,E,ET1, Boulder, CO 80303 USA. RI Bates, John/D-1012-2009; Churnside, James/H-4873-2013 OI Bates, John/0000-0002-8124-0406; NR 12 TC 11 Z9 11 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 15 PY 1999 VL 26 IS 12 BP 1727 EP 1730 DI 10.1029/1999GL900362 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 207DT UT WOS:000080920700022 ER PT J AU Kim, S Ledbetter, H AF Kim, S Ledbetter, H TI Young-modulus determination of an orthotropic thin plate in the through-thickness direction SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID ELASTIC-CONSTANTS AB We give a new approach to obtain the Young modulus of a thin orthotropic plate in the through-thickness-direction. This new approach minimizes errors because eight of nine measurements are made along principal directions. To compare the results, we used a macroscopically orthotropic textured copper plate, which we also measured by acoustic-resonance spectroscopy. The proposed method also yields all off-diagonal elastic coefficients simultaneously and self-consistently. [S0021-8979(99)05212-3]. C1 Natl Inst Stand & Technol, Mat Sci & Engn Lab, Boulder, CO 80303 USA. RP Kim, S (reprint author), Natl Inst Stand & Technol, Mat Sci & Engn Lab, 325 Broadway, Boulder, CO 80303 USA. NR 9 TC 3 Z9 3 U1 1 U2 4 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD JUN 15 PY 1999 VL 85 IS 12 BP 8490 EP 8491 DI 10.1063/1.370631 PG 2 WC Physics, Applied SC Physics GA 200AR UT WOS:000080517000070 ER PT J AU Oey, LY AF Oey, LY TI A forcing mechanism for the poleward flow off the southern California coast SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID SANTA-BARBARA CHANNEL; CIRCULATION; PATTERNS; REGION; MODEL; BIGHT AB It is shown that when the wind distribution along a coast is anisotropic, such that its cross-shore scale is smaller than its alongshore scale, the coastal sea level (or the upper layer anamoly) "A" of an ocean forced by both wind and wind curl is governed by a modified (nondimensionalized) Kelvin wave equation: partial derivative A/partial derivative t* + partial derivative A/partial derivative y* = k(0)(0, y*, t*) + integral partial derivative k(1)/partial derivative y* dt(L) where k(0) and k(1) are wind stress and wind stress curl at the coast, respectively, y is the alongshore distance, and t is the time. Numerical experiments, from a simple reduced-gravity type with idealized forcing and coastline to a three-dimensional primitive equation model with a realistic coastline, bottom topography of the Southern California Eight and the Santa Barbara Channel, and observed wind stresses, were carried out to show that the observed near-coast near-surface poleward flow in the region is primarily forced by the equatorward weakening of the wind curl, (partial derivative k(1)/partial derivative y* >0), in the bight. Beta provides natural damping by weakening and widening the current through westward propagating Rossby waves and causes the current to lead the coastal pressure field by 1-2 months, which improves the agreement with observations of the phasing of the modeled currents but is otherwise not required in forcing the poleward flow. C1 Princeton Univ, Program Atmospher & Ocean Sci, Princeton, NJ 08544 USA. RP Oey, LY (reprint author), Princeton Univ, Program Atmospher & Ocean Sci, Sayre Hall,Forrestal Campus, Princeton, NJ 08544 USA. NR 24 TC 31 Z9 31 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-OCEANS JI J. Geophys. Res.-Oceans PD JUN 15 PY 1999 VL 104 IS C6 BP 13529 EP 13539 DI 10.1029/1999JC900066 PG 11 WC Oceanography SC Oceanography GA 207BF UT WOS:000080914900019 ER PT J AU Frison, TW Earle, MD Abanel, HDI Scherer, WD AF Frison, TW Earle, MD Abanel, HDI Scherer, WD TI Interstation prediction of ocean water levels using methods of nonlinear dynamics SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID GULF-STREAM MODEL; INVERSE PROBLEM; RECONSTRUCTION; ASSIMILATION AB We describe prediction of ocean water levels between geographically separated locations by using a method derived from studies of chaotic dynamical systems. This interstation predictor requires only previously observed water-level data collected simultaneously from the target and baseline water-level measuring stations. The current observations at the baseline station are then used for making the predictions. The method is demonstrated using data from seven "tide" stations with different water level characteristics operated by the U.S. government along the U.S. southeast coast. The data are averaged over 3 min at the sensor to filter out high-frequency motions and are reported at 6-min intervals. Thus the recorded water levels are all ocean surface motions that occur on timescales greater than a few minutes. The predictor forms the reconstructed attractor for both stations using previously observed data. For each new observation at the baseline station, it places the corresponding state-space vector onto the attractor for that station. A map is then derived that associates the neighborhood around that point to the corresponding temporal neighborhood of past observations at the target station. The current observation at the baseline station is then mapped to the appropriate neighborhood for the target station. This is the estimate of the water level at the target station. This method is attractive because the data requirements are simple, the computation burden is low, and there are few decisions about the parameters needed by the algorithm. The state-space predictor compares favorably to traditional methods including statistical correlation, cross-spectral analysis, harmonic analysis, and response analysis. Interstation predictions are important for marine navigation and other applications. The state-space predictor can also provide an objective way of locating tide stations, quantifying the spatial variability of ocean water levels, and identifying regions where ocean water level dynamics are similar. C1 Randle Inc, Great Falls, VA 22066 USA. Neptune Sci Inc, Reston, VA USA. Univ Calif San Diego, Marine Phys Lab, Scripps Inst Oceanog, San Diego, CA USA. Univ Calif San Diego, Inst Nonlinear Sci, San Diego, CA USA. Off Ocean & Earth Sci, Natl Ocean Serv, Natl Ocean & Atmospher Adm, Silver Spring, MD USA. Flinders Univ S Australia, Natl Tidal Facil, Adelaide, SA, Australia. RP Frison, TW (reprint author), Randle Inc, POB 1010, Great Falls, VA 22066 USA. NR 39 TC 2 Z9 3 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 JUN 15 PY 1999 VL 104 IS C6 BP 13653 EP 13666 DI 10.1029/1999JC900025 PG 14 WC Oceanography SC Oceanography GA 207BF UT WOS:000080914900027 ER PT J AU Schonbek, M Vallis, GK AF Schonbek, M Vallis, GK TI Energy decay of solutions to the Boussinesq, primitive, and planetary geostrophic equations SO JOURNAL OF MATHEMATICAL ANALYSIS AND APPLICATIONS LA English DT Article DE partial differential equations; Navier-Stokes equations; estimates ID NAVIER-STOKES EQUATIONS; WEAK SOLUTIONS AB In this paper we study the long time behavior of the energy of solutions to the Boussinesq, planetary geostrophic, and primitive equations. The equations are considered in the whole space R-3. The asymptotic behavior will depend on the type of data and how many damping constants are nonzero in the equations. In several cases we are able to establish an algebraic rate of decay of the same order as the solutions of the underlying linear equations. In the case with less damping our results establish that either the energy of the solutions decays with no rate to an equilibrium or it will be oscillating. (C) 1999 Academic Press. C1 Univ Calif Santa Cruz, Dept Math, Santa Cruz, CA 95064 USA. Princeton Univ, GFDL, Princeton, NJ 08542 USA. RP Schonbek, M (reprint author), Univ Calif Santa Cruz, Dept Math, Santa Cruz, CA 95064 USA. NR 11 TC 5 Z9 5 U1 0 U2 2 PU ACADEMIC PRESS INC PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0022-247X J9 J MATH ANAL APPL JI J. Math. Anal. Appl. PD JUN 15 PY 1999 VL 234 IS 2 BP 457 EP 481 DI 10.1006/jmaa.1999.6354 PG 25 WC Mathematics, Applied; Mathematics SC Mathematics GA 206KG UT WOS:000080877800006 ER PT J AU Grayson, DA Vilker, VL AF Grayson, DA Vilker, VL TI Kinetic characterization of chiral biocatalysis of cycloarenes by the camphor 5-monooxygenase enzyme system SO JOURNAL OF MOLECULAR CATALYSIS B-ENZYMATIC LA English DT Article DE biocatalysis; camphor 5-monooxygenase; cytochrome p-450(cam) hydroxylase; decalin; Michaelis-Menten kinetics; naphthalene; stereochemistry; stoichiometry; tetralin ID CYTOCHROME P-450CAM; HYDROXYLATION; PUTIDAREDOXIN; SUBSTRATE; BINDING; STEREOCHEMISTRY; DEHALOGENATION; MONOXYGENASE; CATALYSIS; TETRALIN AB Redox enzyme mediated biocatalysis has the potential to regio- and stereo-specifically oxidize hydrocarbons producing valuable products with minimal by-product formation. In vitro reactions of the camphor (cytochrome P-450) 5-monooxygenase enzyme system with naphthalene-like substrates yield stereospecifically hydroxylated products from nonactivated hydrocarbons, Specifically, the enzyme system catalyzes the essentially stereospecific conversion of the cycloarene, tetralin (1,2,3,4-tetrahydronaphthalene) to (R)-1-tetralol ((R)-(-)-1,2,3,4-tetrahydro-1-naphthol). It is shown that this reaction obeys Michaelis-Menten kinetics and that interactions between the enzyme subunits are not affected by the identity of the substrate. This subunit independence extends to the efficiency of NADH usage by the enzyme system-subunit ratios do not effect efficiency, but substrate identity does. Tetralin is converted at an efficiency of 13 +/- 3%, whereas (R)-1-tetralol is converted at 7.8 +/- 0.7%. A model of this system based on Michaelis-Menten parameters for one subunit (Pdx: K-M = 10.2 +/- 2 mu M) and both substrates (tetralin: K-M = 66 +/- 26 mu M, nu(max) = 0.11 +/- 0.04 s(-1), and (R)-1-tetralol: K-M = 2800 +/- 1300 mu M, nu(max) = 0.83 +/- 0.22 s(-1)) is presented and used to predict the consumption and production of all substrates, products and cofactors. Published by Elsevier Science B.V. C1 Natl Inst Stand & Technol, Div Biotechnol, Gaithersburg, MD 20899 USA. Univ Calif Los Angeles, Dept Chem Engn, Los Angeles, CA 90095 USA. RP Grayson, DA (reprint author), 3061 Maplewood Pl, Escondido, CA 92027 USA. NR 43 TC 7 Z9 7 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1381-1177 J9 J MOL CATAL B-ENZYM JI J. Mol. Catal. B-Enzym. PD JUN 15 PY 1999 VL 6 IS 6 BP 533 EP 547 DI 10.1016/S1381-1177(99)00003-X PG 15 WC Biochemistry & Molecular Biology; Chemistry, Physical SC Biochemistry & Molecular Biology; Chemistry GA 198AG UT WOS:000080399100002 ER PT J AU Donner, LJ Seman, CJ Hemler, RS AF Donner, LJ Seman, CJ Hemler, RS TI Three-dimensional cloud-system modeling of GATE convection SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID DEEP TROPICAL CONVECTION; CUMULUS ENSEMBLE MODEL; NUMERICAL-SIMULATION; PARAMETERIZATION; SENSITIVITY; RADIATION; BUDGET; FLUXES; WATER; PARAMETRIZATION AB Deep convection and its associated mesoscale circulations are modeled using a three-dimensional elastic model a with bulb microphysics and interactive radiation for a composite easterly wave from the Global Atmospheric Research Program Atlantic Tropical Experiment. The energy and moisture budgets. large-scale heat sources and moisture sinks, microphysics, and radiation are examined. The modeled cloud system undergoes a life cycle dominated by deep convection in its early stages, followed by an upper-tropospheric mesoscale circulation. The large-scale heat sources and moisture sinks associated with the convective system agree broadly with diagnoses from field observations. The modeled upper-tropospheric moisture exceeds observed values. Strong radiative cooling at the top of the mesoscale circulation can produce overturning there. Qualitative features of observed changes in large-scale convective available potential energy and convective inhibition are found in the model integrations, although quantitative magnitudes can differ, especially for convective inhibition. Radiation exerts a strong influence on thr microphysical properties of thr cloud system. The three-dimensional integrations exhibit considerably less sporadic temporal behavior than corresponding two-dimensional integrations. While the third dimension is less important over timescales longer than the duration of a phase of an easterly wave in the lower and middle troposphere, it enables stronger interactions between radiation and dynamics in the upper-tropospheric mesoscale circulation over a substantial fraction of the life cycle of the convective system. C1 Princeton Univ, NOAA, Geophys Fluid Dynam Lab, Princeton, NJ 08544 USA. RP Princeton Univ, NOAA, Geophys Fluid Dynam Lab, POB 308, Princeton, NJ 08544 USA. EM ljd@gfdl.gov NR 41 TC 60 Z9 60 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-4928 EI 1520-0469 J9 J ATMOS SCI JI J. Atmos. Sci. PD JUN 15 PY 1999 VL 56 IS 12 BP 1885 EP 1912 DI 10.1175/1520-0469(1999)056<1885:TDCSMO>2.0.CO;2 PG 28 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 210ZR UT WOS:000081135900008 ER PT J AU Black, RA Hallett, J AF Black, RA Hallett, J TI Electrification of the hurricane SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID CONVECTIVE-SCALE CHARACTERISTICS; ELECTRIC-FIELD MEASUREMENTS; INNER CORE STRUCTURE; RADAR REFLECTIVITY; TROPICAL CYCLONES; MATURE HURRICANES; VERTICAL MOTIONS; RIME ACCRETION; ICE PARTICLES; WATER-CONTENT AB A survey of reports of electrical activity in hurricanes and typhoons from flight notes and personal experience ( 18 years, >230 eyewall penetrations for R. A. Black; similar to 20 years for J. Hallett, plus that of others at the Hurricane Research Division), and perusal of flight notes dating from 1980, show that lightning in and within 100 km or so of the eyewall is usually sparse. However, occasionally, significant electrical activity (>one flash per minute) occurs in or near the eyewall. National Oceanic and Atmospheric Administration WP-3D aircraft penetrations through a number of storms relate the lightning occurrence to strong vertical velocity (>10 m s(-1)) and the presence of supercooled liquid cloud droplets extending To temperatures below -20 degrees C, Specific measurements of cloud properties during eyewall penetrations show that the supercooled cloud water content increases with upward velocities >similar to 5.0 m s(-1), as does the presence of large (>2 mm) supercooled drops. Measurements at temperatures >-13 degrees C show that the transition of supercooled cloud water to ice along an outward radial in all systems is associated with local electric fields (occasionally >20 kV m(-1)) and negative charge above positive charge. In systems with stronger vertical velocity there is a larger region of supercooled cloud extending to lower temperatures where charge separation may occur, as judged by the presence of regions containing graupel, small ice, and cloud droplets. The ratio of ice to supercooled water increases radially outward from the eyewall and depends upon altitude (temperature). The spatial distribution of charge is further influenced by the relation of vertical velocity to the radial flow, with the upper charge regions tending to be advected outward. In symmetrical, mature hurricanes, supercooled water usually occurs only in regions at temperatures above about -5 degrees C. The upward transport of supercooled cloud water is limited by a balance between water condensed in the eyewall updraft and its erosion by ice in downdrafts descending in the outward regions of the eyewall. This ice originates from both primary and secondary ice nucleation in the updraft. This is consistent with an exponential increase in ice concentration, as the rare at which the ice particle concentrations increase depends on the production of secondary particles by preexisting graupel, some of which ultimately grow into new graupel. and its outward transport in the anvil how aloft. Penetrations at temperatures as low as -15 degrees C show the presence of electric fields consistent with specific laboratory-derived criteria for charge separated during ice-graupel collisions, given that a liquid water-dependent sign reversal temperature may occur. Such a reversal may result from either a changing temperature in the vertical, a changing cloud liquid water content in the horizontal, or a combination of the two. Since cloud-to-ground (CG) lightning can be observed with remote detection networks that provide the polarity and frequency of CG lightning, there is potential that hurricane evolution may be detected remotely and that lightning may be usable as an indicator of a change in the storm intensity and/or track. C1 NOAA, Atlantic Oceanog & Meteorol Lab, Hurricane Res Div, Miami, FL 33149 USA. Desert Res Inst, Ctr Atmospher Sci, Reno, NV USA. RP Black, RA (reprint author), NOAA, Atlantic Oceanog & Meteorol Lab, Hurricane Res Div, 4301 Rickenbacker Cswy, Miami, FL 33149 USA. RI Black, Robert/C-9617-2009 OI Black, Robert/0000-0001-6938-125X NR 66 TC 76 Z9 87 U1 2 U2 14 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 JUN 15 PY 1999 VL 56 IS 12 BP 2004 EP 2028 DI 10.1175/1520-0469(1999)056<2004:EOTH>2.0.CO;2 PG 25 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 210ZR UT WOS:000081135900014 ER PT J AU Lovell, LG Stansbury, JW Syrpes, DC Bowman, CN AF Lovell, LG Stansbury, JW Syrpes, DC Bowman, CN TI Effects of composition and reactivity on the reaction kinetics of dimethacrylate dimethacrylate copolymerizations SO MACROMOLECULES LA English DT Article ID CHAIN CROSSLINKING PHOTOPOLYMERIZATION; METHYL-METHACRYLATE; VOLUME RELAXATION; NETWORK FORMATION; POLYMERIZATION; CONVERSION; RESINS; TERMINATION; DIFFUSION; MONOMER AB The bis-GMA (2,2-bis[4-(2-hydroxy-3-methacryloyloxy)phenyl]propane) and TEGD-MA (triethylene glycol dimethacrylate) copolymerization has been often used as the organic phase of dental composites and is a good example of a dimethacrylate/dimethacrylate polymerization involving a viscous monomer and a reactive diluent. This work focuses on the kinetic behavior of this monomer system and the effect of monomer structure, viscosity, and comonomer concentration on the mobility and reactivity of the evolving network. Unsteady-state polymerizations were performed using various compositions of bis-GMA/TEGDMA to obtain the kinetic parameters as a function of double-bond conversion. Furthermore, TEGDMA and bis-GMA were hydrogenated, i.e., the double bonds were saturated, and utilized to study the effect of each reactive component on the copolymerization. The results suggest that reaction diffusion-controlled termination dominates as the reaction progresses and that bis-GMA plays a more controlling role in the kinetics than TEGDMA. In addition, the hydrogenated monomers were used to determine the effect of viscosity on the homopolymerization of dimethacrylates. It was shown that the addition of a solvent, i.e., hydrogenated TEGDMA, to the bis-GMA system had a more pronounced effect on the polymerization kinetics than TEGDMA polymerized in the presence of viscous hydrogenated bis-GMA. The difference in the kinetic behavior was attributed to the relative mobilities of each monomer. C1 Univ Colorado, Dept Chem Engn, Boulder, CO 80309 USA. Natl Inst Stand & Technol, Div Polymers, Gaithersburg, MD 20899 USA. RP Bowman, CN (reprint author), Univ Colorado, Dept Chem Engn, Boulder, CO 80309 USA. RI Bowman, Christopher/B-1490-2008 OI Bowman, Christopher/0000-0001-8458-7723 NR 28 TC 124 Z9 128 U1 1 U2 12 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0024-9297 J9 MACROMOLECULES JI Macromolecules PD JUN 15 PY 1999 VL 32 IS 12 BP 3913 EP 3921 DI 10.1021/ma990258d PG 9 WC Polymer Science SC Polymer Science GA 207TM UT WOS:000080951900013 ER PT J AU Prosa, TJ Moulton, J Heeger, AJ Winokur, MJ AF Prosa, TJ Moulton, J Heeger, AJ Winokur, MJ TI Diffraction line-shape analysis of poly(3-dodecylthiophene): A study of layer disorder through the liquid crystalline polymer transition SO MACROMOLECULES LA English DT Article ID X-RAY-DIFFRACTION; PROFILE ANALYSIS; STRUCTURAL-ANALYSIS; BROADENING ANALYSIS; THERMAL-BEHAVIOR; MOLECULAR-WEIGHT; ZIRCONIA POWDERS; FOURIER-ANALYSIS; POLY(3-ALKYLTHIOPHENES); SIZE AB The nature of the structural ordering within semicrystalline poly(3-dodecylthiophene) films has been analyzed using a Warren-Averbach Line-shape analysis which includes up to five orders of the (h00) lattice reflections. This analysis yields a semiquantitative measure of the volume averaged crystallite sizes, the lattice parameter variations, and the disorder fluctuations. The progression of these quantities has been followed through a liquid crystal polymer (LCP) phase transition which occurs in the vicinity of 60 degrees C. The pronounced peak width narrowing of the low-order (h00) reflections, observed on heating, is found to be essentially uncorrelated with a theorized annealing-induced increase in average crystallite size. The major contribution to this narrowing arises from systematic variations in the microscopic heterogeneities and fluctuations. Moreover, Re observe an anomalously large increase in the higher-order (h00) (h = 3-5) peak widths at temperatures spanning that of the thermotropic LCP transition. This effect is found to be strongly correlated with a maximum in the disorder fluctuations, and this relationship suggests an underlying mechanism for the nature of the LCP transition. C1 Univ Wisconsin, Dept Phys, Madison, WI 53706 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Univ Calif Santa Barbara, Dept Phys, Santa Barbara, CA 93105 USA. Univ Calif Santa Barbara, IPOS, Santa Barbara, CA 93105 USA. RP Winokur, MJ (reprint author), Univ Wisconsin, Dept Phys, 1150 Univ Ave, Madison, WI 53706 USA. NR 66 TC 53 Z9 53 U1 0 U2 12 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0024-9297 J9 MACROMOLECULES JI Macromolecules PD JUN 15 PY 1999 VL 32 IS 12 BP 4000 EP 4009 DI 10.1021/ma981059h PG 10 WC Polymer Science SC Polymer Science GA 207TM UT WOS:000080951900026 ER PT J AU Zhang, JZ Fischer, CH Ortner, PB AF Zhang, JZ Fischer, CH Ortner, PB TI Optimization of performance and minimization of silicate interference in continuous flow phosphate analysis SO TALANTA LA English DT Article DE phosphate determination; silicate interference; coating; continuous flow analysis ID PHOSPHOANTIMONYLMOLYBDENUM BLUE COMPLEX; PHOSPHORUS LIMITATION; MARINE-ENVIRONMENT; AQUEOUS-SOLUTION; MOLYBDENUM BLUE; NATURAL-WATERS; EVOLUTION; ARSENATE; OCEAN AB Specific reaction conditions for automated continuous flow analysis of phosphate are optimized in regard to minimizing coating and silicate interference, while maintaining high sensitivity. Use of Sb in the reagent increases sensitivity and yields absorbances with little temperature dependence. Coating can be minimized by using a final solution at a pH > 0.5. At final pH of 0.78 there is maximum interference from silicate in the sample. We recommend therefore as an optimal reaction condition with minimal silicate interference, the use of Sb, a final solution pH of 1.00, room temperature for the reaction and a [H+]/[Mo] ratio of 70. An equation is provided to correct silicate interference in high precision phosphate determination. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Miami, Rosenstiel Sch Marine & Atmospher Sci, CIMAS, Miami, FL 33149 USA. NOAA, Atlantic Oceanog & Meteorol Lab, Ocean Chem Div, Miami, FL 33149 USA. RP Zhang, JZ (reprint author), Univ Miami, Rosenstiel Sch Marine & Atmospher Sci, CIMAS, 4600 Rickenbacker Causeway, Miami, FL 33149 USA. RI Zhang, Jia-Zhong/B-7708-2008; Fischer, Charles/A-3843-2017 OI Zhang, Jia-Zhong/0000-0002-1138-2556; NR 46 TC 65 Z9 69 U1 0 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-9140 J9 TALANTA JI Talanta PD JUN 14 PY 1999 VL 49 IS 2 BP 293 EP 304 DI 10.1016/S0039-9140(98)00377-4 PG 12 WC Chemistry, Analytical SC Chemistry GA 211CU UT WOS:000081143000008 PM 18967600 ER PT J AU Slack, PD Fox, CG Dziak, RP AF Slack, PD Fox, CG Dziak, RP TI P wave detection thresholds, Pn velocity estimates, and T wave location uncertainty from oceanic hydrophones SO JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH LA English DT Article ID DE-FUCA RIDGE; SEISMIC REFRACTION; CRUSTAL STRUCTURE; UPPER MANTLE; SEA-FLOOR; PHASES; ATTENUATION; SCATTERING; PACIFIC; ARRAYS AB P wave arrivals recorded by the U.S. Navy's SOund SUrveillance System (SOSUS) hydrophone arrays were used to estimate earthquake detection thresholds and Pn velocities in the northeast Pacific Ocean. The Navy hydrophones have been used successfully to detect and locate oceanic earthquakes using their waterborne acoustic tertiary (T) waves; however, use of these hydrophones for seismic body wave detection allows regional seismic analyses to be extended to the oceanic environment. The P wave detection threshold of the SOSUS hydrophones was quantified using the epicentral distance and magnitude of 250 northeast Pacific Ocean earthquakes. Earthquakes with body wave magnitudes as low as 2 have detectable P wave arrivals at epicentral distances of less than or equal to 500 km. Earthquakes with mb between 3.5 and 5 were detected similar to 50% of the time at distances of 100-1500 km, while events with m(b) > 5 were all detected, even out to distances of 1000-1500 km. Both P and T wave hydrophone arrival times were used to estimate the epicenters of 100 earthquakes. The peak amplitude of the T wave coda and the onset of the P wave were used as the earthquake arrival times to estimate event locations. T wave arrival time residuals have a Gaussian distribution with zero mean, which implies that using T wave peak amplitude is consistent with using the P wave onset as the arrival time. There are typically less than or equal to 6 stations used to derive a T wave based location, hence location error ellipses are not well constrained, A Monte Carlo technique was employed to estimate T wave event location uncertainty. T wave locations have error bars of similar to 1 km in latitude and longitude when >3 hydrophones are used for a location estimate. The detected P wave arrivals and earthquake locations were used to measure Pn velocities. Pn velocity values of 7.9 +/- 0.1 and 8.0 +/- 0.1 km/s were found for the Pacific and Juan de Fuca plates, respectively. A Pn velocity of 7.5 +/- 0.1 km/s was measured for rays traveling northward from the Mendocino Triple Junction along the Cascadia subduction zone. A Pn velocity of 7.7 +/- 0.3 km/s was estimated for ray paths originating onshore western North America and traveling to the offshore hydrophones. C1 Aqua Environm Co Inc, San Rafael, CA 94901 USA. Hatfield Marine Sci Ctr, Natl Ocean & Atmospher Adm, Pacific Marine Environm Lab, Newport, OR 97365 USA. Oregon State Univ, Hatfield Marine Sci Ctr, Cooperat Inst Marine Resources Studies, Newport, OR 97365 USA. RP Slack, PD (reprint author), Aqua Environm Co Inc, 3100 Kerner Blvd,Suite N, San Rafael, CA 94901 USA. EM pslack@linex.com; fox@pmel.noaa.gov; dziak@pmel.noaa.gov NR 34 TC 33 Z9 33 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 1999 VL 104 IS B6 BP 13061 EP 13072 DI 10.1029/1999JB900112 PG 12 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 205GM UT WOS:000080813000023 ER PT J AU O'Connell, PA McKenna, GB AF O'Connell, PA McKenna, GB TI Arrhenius-type temperature dependence of the segmental relaxation below T-g SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID DIELECTRIC-RELAXATION; GLASS-TRANSITION; ORGANIC LIQUIDS; POLYMERS; POLYCARBONATE; VISCOSITY; DYNAMICS AB In a recent paper DiMarzio and Yang [J. Res. Natl. Inst. Stand. Technol. 102, 135 (1997)] predicted that transport properties such as viscosity and diffusion coefficient do not follow the typical Williams, Landel, and Ferry (WLF) [J. Am. Chem. Soc. 77, 3701 (1955)] or Vogel-Fulcher-type of temperature dependence as the glass transition is approached. Rather, a transition to an Arrhenius-type of temperature dependence is predicted. Here we describe long term aging experiments that explore the temperature dependence of the viscoelastic response of polycarbonate in the vicinity of the glass transition. Aging the material for long times below the nominal glass transition temperature, assures that equilibrium is attained and we can directly test the DiMarzio-Yang prediction. In tests in which glassy samples of polycarbonate were aged into equilibrium at temperatures up to 17 degrees C below the conventionally measured glass transition temperature, we find that the results are consistent with a transition from Vogel-Fulcher or WLF-type behavior to Arrhenius-type behavior. Our results are discussed within the context of other measurements on nonpolymeric glasses and other recent results on polymeric glass formers. [S0021-9606(99)50222-5]. C1 Natl Inst Stand & Technol, Div Polymers, Gaithersburg, MD 20899 USA. RP McKenna, GB (reprint author), Natl Inst Stand & Technol, Div Polymers, Gaithersburg, MD 20899 USA. RI McKenna, Gregory/O-1134-2013 OI McKenna, Gregory/0000-0002-5676-9930 NR 51 TC 129 Z9 129 U1 3 U2 34 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD JUN 8 PY 1999 VL 110 IS 22 BP 11054 EP 11060 DI 10.1063/1.479046 PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 199FF UT WOS:000080469200049 ER PT J AU Nisato, G Munch, JP Candau, SJ AF Nisato, G Munch, JP Candau, SJ TI Swelling, structure, and elasticity of polyampholyte hydrogels SO LANGMUIR LA English DT Article; Proceedings Paper CT 2nd International Symposium on Polyelectrolytes CY MAY 31-JUN 03, 1998 CL INUYAMA, JAPAN ID POLYELECTROLYTE GELS; LIGHT-SCATTERING; MULTIPLE PHASES; POLYMER GELS; ACID) GELS; FLUCTUATIONS; CHARGE; SALT; CONFORMATION; BEHAVIOR AB yWe studied the swelling and elastic behavior of chemically cross-linked [2-(methacryloyloxy)-ethyltrimethylammonium chloride-2-(acrylamido)-3-ethylpropanesulfonate] polyampholyte gels in equilibrium with saline solutions. The net charge of the polymer network and the ionic strength of the swelling solvent are crucial parameters governing the properties of the gels. The swelling equilibrium behavior of gels with a strong charge imbalance was analogous to polyelectrolyte systems (monotonic decrease of swelling ratio with rising salt concentration). Globally neutral gels showed an antipolyelectrolyte behavior (collapse at low ionic strength and monotonic increase of swelling ratio with rising salt concentration). Weakly unbalanced polyampholyte gels showed a characteristic minimum in their swelling curves, the same gel reaching the same equilibrium volume in two different ionic conditions. The internal structure was imaged using differential interference contrast microscopy and revealed that morphological modifications of the gel structure accompany volume variations. The evolution of the elastic modulus of polyampholyte gels at equilibrium is quite complex, because the same sample can behave like a polyelectrolyte in low ionic strength conditions and as a balanced polyampholyte at high ionic strength, Thus a polyampholyte gel can reach the same swelling ratio at equilibrium for two different ionic strengths, but is then characterized by two different values of the shear modulus. C1 ULP, CNRS, UMR 7506, Lab Dynam Fluides Complexes, F-67070 Strasbourg, France. RP Nisato, G (reprint author), Natl Inst Stand & Technol, Div Polymers, Gaithersburg, MD 20899 USA. NR 47 TC 71 Z9 74 U1 3 U2 23 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0743-7463 J9 LANGMUIR JI Langmuir PD JUN 8 PY 1999 VL 15 IS 12 BP 4236 EP 4244 DI 10.1021/la981027n PG 9 WC Chemistry, Multidisciplinary; Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA 206KV UT WOS:000080879000036 ER PT J AU Bao, W Raymond, S Shapiro, SM Motoya, K Fak, B Erwin, RW AF Bao, W Raymond, S Shapiro, SM Motoya, K Fak, B Erwin, RW TI Unconventional ferromagnetic and spin-glass states of the reentrant spin glass Fe0.7Al0.3 SO PHYSICAL REVIEW LETTERS LA English DT Article ID NEUTRON-SCATTERING; DYNAMICS; ALLOYS; COEXISTENCE; TRANSITION; BEHAVIOR; FEXCR1-X AB Spin excitations in a single crystal of Fe0.7Al0.3 were investigated over a wide range pf energy and reciprocal space with inelastic neutron scattering. In the ferromagnetic phase, propagating spin wave modes become paramagnonlike diffusive modes beyond a critical wave vector q(0), indicating substantial disorder in the long-range ordered state. In the spin glass phase, the spin dynamics are strongly q dependent, suggesting remnant short-range spin correlations. [S0031-9007(99)09306-0]. C1 Brookhaven Natl Lab, Upton, NY 11973 USA. Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. CEA Grenoble, DRFMC, SPSMS, F-38054 Grenoble, France. Sci Univ Tokyo, Noda, Chiba 278, Japan. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Bao, W (reprint author), Brookhaven Natl Lab, Upton, NY 11973 USA. RI Bao, Wei/E-9988-2011 OI Bao, Wei/0000-0002-2105-461X NR 32 TC 42 Z9 42 U1 1 U2 6 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 7 PY 1999 VL 82 IS 23 BP 4711 EP 4714 DI 10.1103/PhysRevLett.82.4711 PG 4 WC Physics, Multidisciplinary SC Physics GA 202ZK UT WOS:000080682300036 ER PT J AU Bruno, TJ Lewandowska, A Tsvetkov, F Hanley, HJM AF Bruno, TJ Lewandowska, A Tsvetkov, F Hanley, HJM TI Determination of heats of adsorption of hydrocarbons on a synthetic clay by gas-solid chromatography using a wall coated open tubular column approach SO JOURNAL OF CHROMATOGRAPHY A LA English DT Article DE adsorption; clays; heats of adsorption; laponite-RD clay; thermodynamic parameters; hydrocarbons ID PRESSURE LIQUID-CHROMATOGRAPHY; GRAPHITIZED CARBON-BLACK; MONTMORILLONITE; HALOCARBONS; RETENTION AB Heats of adsorption for a series of hydrocarbons on Laponite-RD clay were determined by two gas chromatographic methods. The first method was an extension of packed-column gas-solid chromatography. The second method employed a novel wall coated open tubular (WCOT) column that was prepared from clay aqueous suspensions. The two different methods of preparing chromatographic columns are discussed in this paper, and a comparison between the results obtained on the two systems is made. We conclude that the WCOT column method provides the same thermodynamic results as does the conventional packed-column method, while offering some definite improvements in the measurement process and data behavior. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Natl Inst Stand & Technol, Phys & Chem Properties Div, Chem Sci & Technol Lab, Boulder, CO 80303 USA. Daren Labs & Sci Consultants, Nes Ziona, Israel. RP Bruno, TJ (reprint author), Natl Inst Stand & Technol, Phys & Chem Properties Div, Chem Sci & Technol Lab, 325 Broadway, Boulder, CO 80303 USA. NR 17 TC 9 Z9 9 U1 1 U2 2 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 4 PY 1999 VL 844 IS 1-2 BP 191 EP 199 DI 10.1016/S0021-9673(99)00414-8 PG 9 WC Biochemical Research Methods; Chemistry, Analytical SC Biochemistry & Molecular Biology; Chemistry GA 210DT UT WOS:000081090400017 ER PT J AU Mills, KL AF Mills, KL TI Introduction to the electronic symposium on computer-supported cooperative work SO ACM COMPUTING SURVEYS LA English DT Article DE asynchronous collaboration; computer-supported collaborative work; human-computer interaction; information management; multimedia collaboration; multimodal collaboration AB Computer-supported cooperative work (CSCW) holds great importance and promise for modern society. This paper provides an overview of seventeen papers comprising a symposium on CSCW. The overview also discusses some relationships among the contributions made by each paper, and places those contributions into a larger context by identifying some of the key challenges faced by computer science researchers who aim to help us work effectively as teams mediated through networks of computers. The paper also describes why the promise of CSCW holds particular salience for the U.S. military. In the context of a military setting, the paper describes five particular challenges for CSCW researchers. While most of these challenges might seem specific to military environments, many others probably already face similar challenges, or soon will, when attempting to collaborate through networks of computers. To support this claim, the paper includes a military scenario that might hit fairly close to home for many, and certainly for civilian emergency response personnel. After discussing the military needs for collaboration technology, the paper briefly outlines the motivation for a recent DARPA research program along these lines. That program, called Intelligent Collaboration and Visualization, sponsored the work reported in this symposium. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Def Adv Res Projects Agcy, Arlington, VA USA. RP Mills, KL (reprint author), Natl Inst Stand & Technol, 820 W Diamond Ave, Gaithersburg, MD 20899 USA. NR 0 TC 8 Z9 8 U1 1 U2 4 PU ASSOC COMPUTING MACHINERY PI NEW YORK PA 1515 BROADWAY, NEW YORK, NY 10036 USA SN 0360-0300 J9 ACM COMPUT SURV JI ACM Comput. Surv. PD JUN PY 1999 VL 31 IS 2 BP 105 EP 115 DI 10.1145/319806.319810 PG 11 WC Computer Science, Theory & Methods SC Computer Science GA 260QQ UT WOS:000083961700001 ER PT J AU Damianos, L Hirschman, L Kozierok, R Kurtz, J Greenberg, A Walls, K Laskowski, S Scholtz, J AF Damianos, L Hirschman, L Kozierok, R Kurtz, J Greenberg, A Walls, K Laskowski, S Scholtz, J TI Evaluation for collaborative systems SO ACM COMPUTING SURVEYS LA English DT Article C1 Mitre Corp, Bedford, MA 01730 USA. NIMA Washington Navy Yard, Washington, DC 20505 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Damianos, L (reprint author), Mitre Corp, 202 Burlington Rd, Bedford, MA 01730 USA. NR 6 TC 1 Z9 1 U1 0 U2 0 PU ASSOC COMPUTING MACHINERY PI NEW YORK PA 1515 BROADWAY, NEW YORK, NY 10036 USA SN 0360-0300 J9 ACM COMPUT SURV JI ACM Comput. Surv. PD JUN PY 1999 VL 31 SU 2 BP U92 EP U98 PG 7 WC Computer Science, Theory & Methods SC Computer Science GA 303BY UT WOS:000086402000015 ER PT J AU Mills, KL AF Mills, KL TI Introduction to the electronic symposium on computer-supported cooperative work SO ACM COMPUTING SURVEYS LA English DT Editorial Material DE asynchronous collaboration; computer-supported collaborative work; human-computer interaction; information management; multimedia collaboration; multimodal collaboration AB Computer-supported cooperative work (CSCW) holds great importance and promise for modern society. This paper provides an overview of seventeen papers comprising a symposium on CSCW. The overview also discusses some relationships among the contributions made by each paper, and places those contributions into a larger context by identifying some of the key challenges faced by computer science researchers who aim to help us work effectively as teams mediated through networks of computers. The paper also describes why the promise of CSCW holds particular salience for the U.S. military. In the context of a military setting, the paper describes five particular challenges for CSCW researchers. While most of these challenges might seem specific to military environments, many others probably already face similar challenges, or soon will, when attempting to collaborate through networks of computers. To support this claim, the paper includes a military scenario that might hit fairly close to home for many, and certainly for civilian emergency response personnel. After discussing the military needs for collaboration technology, the paper briefly outlines the motivation for a recent DARPA research program along these lines. That program, called Intelligent Collaboration and Visualization, sponsored the work reported in this symposium. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Mills, KL (reprint author), Natl Inst Stand & Technol, 820 W Diamond Ave, Gaithersburg, MD 20899 USA. NR 7 TC 0 Z9 0 U1 0 U2 1 PU ASSOC COMPUTING MACHINERY PI NEW YORK PA 1515 BROADWAY, NEW YORK, NY 10036 USA SN 0360-0300 J9 ACM COMPUT SURV JI ACM Comput. Surv. PD JUN PY 1999 VL 31 SU 2 BP U1 EP U11 PG 11 WC Computer Science, Theory & Methods SC Computer Science GA 303BY UT WOS:000086402000001 ER PT J AU Ranganathan, M Andrey, L Schaal, V Favreau, JP AF Ranganathan, M Andrey, L Schaal, V Favreau, JP TI Re-configurable distributed scripting SO ACM COMPUTING SURVEYS LA English DT Article AB Several distributed testing, control and collaborative applications are reactive or event driven in nature. Such applications can be structured as a set of handlers that react to events and that in turn can trigger other events. We have developed an application building toolkit that facilitates development of such applications. Our system is based on the concept of Mobile Streams. Applications developed in our system are dynamically extensible and re-configurable and our system provides the application designer a mechanism to control extension and re-configuration. We describe our system model and give examples of its use. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Ranganathan, M (reprint author), Natl Inst Stand & Technol, 820 W Diamond Ave, Gaithersburg, MD 20899 USA. NR 4 TC 0 Z9 0 U1 0 U2 1 PU ASSOC COMPUTING MACHINERY PI NEW YORK PA 1515 BROADWAY, NEW YORK, NY 10036 USA SN 0360-0300 J9 ACM COMPUT SURV JI ACM Comput. Surv. PD JUN PY 1999 VL 31 SU 2 BP U99 EP U102 PG 4 WC Computer Science, Theory & Methods SC Computer Science GA 303BY UT WOS:000086402000016 ER PT J AU Ladner, JE Abdulaev, NG Kakuev, DL Tordova, M Ridge, KD Gilliland, GL AF Ladner, JE Abdulaev, NG Kakuev, DL Tordova, M Ridge, KD Gilliland, GL TI The three-dimensional structures of two isoforms of nucleoside diphosphate kinase from bovine retina SO ACTA CRYSTALLOGRAPHICA SECTION D-BIOLOGICAL CRYSTALLOGRAPHY LA English DT Article ID X-RAY STRUCTURE; CRYSTAL-STRUCTURE; MACROMOLECULAR STRUCTURES; 2-ANGSTROM RESOLUTION; HUMAN-ERYTHROCYTES; PURIFICATION; DROSOPHILA; ENZYME; CRYSTALLOGRAPHY; PHOTORECEPTORS AB The crystal structures of two isoforms of nucleoside diphosphate kinase from bovine retina overexpressed in Escherischia coli have been determined to 2.4 Angstrom resolution. Both the isoforms, NBR-A and NBR-B, are hexameric and the fold of the monomer is in agreement with NDP-kinase structures from other biological sources. Although the polypeptide chains of the two isoforms differ by only two residues, they crystallize in different space groups. NBR-A crystallizes in space group P2(1)2(1)2(1) with an entire hexamer in the asymmetric unit, while NBR-B crystallizes in space group P4(3)2(1)2 with a trimer in the asymmetric unit. The highly conserved nucleotide-binding site observed in other nucleoside diphosphate kinase structures is also observed here, Both NBR-A and NBR-B were crystallized in the presence of cGMP. The nucleotide is bound with the base in the anti conformation. The NBR-A active site contained both cGMP and GDP each bound at half occupancy. Presumably, NBR-A had retained GDP (or GTP) from the purification process. The NBR-B active site contained only cGMP. C1 Natl Inst Stand & Technol, Ctr Adv Res Biotechnol, Rockville, MD 20850 USA. Univ Maryland, Inst Biotechnol, Rockville, MD 20850 USA. Russian Acad Sci, Shemyakin & Ovchinnikov Inst Bioorgan Chem, Lab Light Sensit Syst, Moscow, Russia. RP Gilliland, GL (reprint author), Natl Inst Stand & Technol, Ctr Adv Res Biotechnol, 9600 Gudelsky Dr, Rockville, MD 20850 USA. NR 43 TC 9 Z9 9 U1 0 U2 1 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 1999 VL 55 BP 1127 EP 1135 DI 10.1107/S0907444999002528 PN 6 PG 9 WC Biochemical Research Methods; Biochemistry & Molecular Biology; Biophysics; Crystallography SC Biochemistry & Molecular Biology; Biophysics; Crystallography GA 208NG UT WOS:000080997500003 PM 10329774 ER PT J AU Burke, JS Seikai, T Tanaka, Y Tanaka, M AF Burke, JS Seikai, T Tanaka, Y Tanaka, M TI Experimental intensive culture of summer flounder, Paralichthys dentatus SO AQUACULTURE LA English DT Article; Proceedings Paper CT Flatfish Symposium held in conjunction with the World-Aquaculture-Society Annual Meeting CY JAN, 1998 CL LAS VEGAS, NEVADA SP World Aquaculture Soc DE Paralichthys dentatus; P-olivaceus; intensive culture; temperature; growth; mortality; pigmentation ID OLIVACEUS; LARVAE; ROTIFERS; GROWTH AB Summer flounder were cultured based on techniques developed for the Japanese flounder, Paralichthys olivaceus. For production of early juveniles, three water temperatures (18, 20 and 22 degrees C) were tested. Larvae were hatched and reared through first feeding at relatively high concentration (30-60/l). Preflexion larvae were stocked in nine 100 1 tanks at concentrations of 10 larvae/l and harvested as juveniles of 1.75-3.5 cm. Duration of temperature trials varied with temperature from 42 to 58 days. Survival varied from 0.5 to 63% with low survival due to outbreaks of disease in some tanks. In tanks without disease, relatively low survival (43%) appeared to be due to cannibalism. The occurrence of albinic (hypomelanisys) juveniles was from 5 to 10% and appeared to be negatively correlated with temperature. The occurrence of right eyed (reversal) fish was 0 to 3.5% and appeared independent of temperature. Summer flounder may require smaller prey during first feeding than Japanese flounder; however, results indicate that once first feeding is accomplished the Japanese culture system can produce summer flounder juveniles efficiently. (C) 1999 Elsevier Science B.V. All rights reserved. C1 NOAA, Natl Marine Fisheries Serv, Beaufort Lab, Beaufort, NC 28516 USA. Kyoto Univ, Fisheries Res Stn, Kyoto 625, Japan. Kyoto Univ, Grad Sch Agr, Div Appl Biosci, Lab Marine Stock Enhancement Biol, Kyoto 6068502, Japan. RP Burke, JS (reprint author), NOAA, Natl Marine Fisheries Serv, Beaufort Lab, Beaufort, NC 28516 USA. NR 20 TC 26 Z9 28 U1 1 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0044-8486 J9 AQUACULTURE JI Aquaculture PD JUN 1 PY 1999 VL 176 IS 1-2 BP 135 EP 144 DI 10.1016/S0044-8486(99)00056-3 PG 10 WC Fisheries; Marine & Freshwater Biology SC Fisheries; Marine & Freshwater Biology GA 202VU UT WOS:000080673500013 ER PT J AU Venizelos, A Benetti, DD AF Venizelos, A Benetti, DD TI Pigment abnormalities in flatfish SO AQUACULTURE LA English DT Article; Proceedings Paper CT Flatfish Symposium held in conjunction with the World-Aquaculture-Society Annual Meeting CY JAN, 1998 CL LAS VEGAS, NEVADA SP World Aquaculture Soc DE flatfish; albinism; pseudo-albinism; hypomelanosis; hypermelanosis; ambicoloration ID FLOUNDER PARALICHTHYS LETHOSTIGMA; LIGHT-INTENSITY; ALBINISM; OLIVACEUS; SURVIVAL; JUVENILE; GROWTH AB Pigment abnormalities have been reported to occur on both sides of flatfish.,Hypomelanosis or pseudo-albinism, characterized by white patches or areas devoid of normal pigmentation on the ocular surface of the skin, is common in both wild and hatchery reared flatfish. The blind side may display hypermelanosis in the form of dark spots, known as ambicoloration of the skin. The etiology of these abnormalities is not well understood. Environmental, nutritional and neurological aspects which may be involved are reviewed and approaches for future research are identified. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Natl Marine Fisheries Serv, NOAA, SE Fisheries Sci Ctr, Virginia Key, FL 33149 USA. Univ Miami, Rosenstiel Sch Marine & Atmospher Sci, Virginia Key, FL USA. RP Venizelos, A (reprint author), Natl Marine Fisheries Serv, NOAA, SE Fisheries Sci Ctr, 75 Virginia Beach Dr, Virginia Key, FL 33149 USA. NR 52 TC 56 Z9 69 U1 2 U2 8 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0044-8486 J9 AQUACULTURE JI Aquaculture PD JUN 1 PY 1999 VL 176 IS 1-2 BP 181 EP 188 DI 10.1016/S0044-8486(99)00060-5 PG 8 WC Fisheries; Marine & Freshwater Biology SC Fisheries; Marine & Freshwater Biology GA 202VU UT WOS:000080673500017 ER PT J AU Pleim, JE Finkelstein, PL Clarke, JF Ellestad, TG AF Pleim, JE Finkelstein, PL Clarke, JF Ellestad, TG TI A technique for estimating dry deposition velocities based on similarity with latent heat flux SO ATMOSPHERIC ENVIRONMENT LA English DT Article DE dry deposition; ozone; stomatal resistance; soybeans; trace gas fluxes; latent heat flux ID OZONE DEPOSITION; DECIDUOUS FOREST; SURFACE; CANOPY; RESISTANCE; FIFE; CONDUCTANCE; VEGETATION; MODEL; SCALE AB Field measurements of chemical dry deposition are needed to assess impacts and trends of airborne contaminants on the exposure of crops and unmanaged ecosystems as well as for the development and evaluation of air quality models. However, accurate measurements of dry deposition velocities require expensive eddy correlation measurements and can only be practically made for a few chemical species such as O-3 and CO2. On the other hand, operational dry deposition measurements such as those used in large area networks involve relatively inexpensive standard meteorological and chemical measurements but rely on less accurate deposition velocity models. This paper describes an intermediate technique which can give accurate estimates of dry deposition velocity for chemical species which are dominated by stomatal uptake such as O-3 and SO2. This method can give results that are nearly the quality of eddy correlation measurements of trace gas fluxes at much lower cost. The concept is that bulk stomatal conductance can be accurately estimated from measurements of latent heat flux combined with standard meteorological measurements of humidity, temperature, and wind speed. The technique is tested using data from a field experiment where high quality eddy correlation measurements were made over soybeans, Over a four month period, which covered the entire growth cycle, this technique showed very good agreement with eddy correlation measurements for O-3 deposition velocity. Published by Elsevier Science Ltd. C1 US EPA, Natl Exposure Res Lab, Res Triangle Pk, NC 27711 USA. Natl Ocean & Atmospher Adm, Atmospher Sci Modeling Div, Air Resources Lab, Res Triangle Pk, NC 27711 USA. RP Pleim, JE (reprint author), US EPA, Natl Exposure Res Lab, Res Triangle Pk, NC 27711 USA. RI Pleim, Jonathan Pleim/C-1331-2017 OI Pleim, Jonathan Pleim/0000-0001-6190-6082 NR 32 TC 17 Z9 17 U1 1 U2 6 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1352-2310 J9 ATMOS ENVIRON JI Atmos. Environ. PD JUN PY 1999 VL 33 IS 14 BP 2257 EP 2268 DI 10.1016/S1352-2310(98)00162-9 PG 12 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA 187GL UT WOS:000079778700010 ER PT J AU Messina, E Horst, J Kramer, T Huang, H Michaloski, J AF Messina, E Horst, J Kramer, T Huang, H Michaloski, J TI Component specifications for robotics integration SO AUTONOMOUS ROBOTS LA English DT Article DE software components; software reuse; frameworks; intelligent systems; software architectures ID OBJECT POSE; SYSTEM AB Robotics researchers have been unable to capitalize easily on existing software components to speed up their development efforts and maximize their system's capabilities. A component-based approach for building the software for robotics systems can provide reuse and sharing abilities to the research community. The software engineering community has been studying reuse techniques for three decades. We present several results from those efforts that are applicable to the robotics software integration problem. We describe how to specify a software component so that a potential user may understand its capabilities and facilitate its application to his or her system. At the National Institute of Standards and Technology, we have developed a three-stage, component-specification approach. We illustrate this approach for a component that is relevant to robotics. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. OI Messina, Elena/0000-0002-1727-9357 NR 57 TC 4 Z9 4 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0929-5593 EI 1573-7527 J9 AUTON ROBOT JI Auton. Robot. PD JUN PY 1999 VL 6 IS 3 BP 247 EP 264 DI 10.1023/A:1008980211618 PG 18 WC Computer Science, Artificial Intelligence; Robotics SC Computer Science; Robotics GA 204YH UT WOS:000080793200002 ER PT J AU Abramowitz, S AF Abramowitz, Stanley TI DNA Analysis in Microfabricated Formats SO BIOMEDICAL MICRODEVICES LA English DT Article AB The use of microfabricated DNA analysis tools utilizing microfluidics will provide the next generation of inexpensive DNA diagnostics. It will also provide methodologies to measure gene expression in a massively parallel manner, eventually providing the methodologies to measure most or all the human genes of significance on a single chip. These technologies, including PCR analysis, electrophoresis and gene chips are described using examples from the archival literature. C1 NIST, Adv Technol Program, Gaithersburg, MD 20899 USA. RP Abramowitz, S (reprint author), NIST, Adv Technol Program, Gaithersburg, MD 20899 USA. NR 63 TC 4 Z9 4 U1 1 U2 2 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 1387-2176 EI 1572-8781 J9 BIOMED MICRODEVICES JI Biomed. Microdevices PD JUN PY 1999 VL 1 IS 2 BP 107 EP 112 DI 10.1023/A:1009992306940 PG 6 WC Engineering, Biomedical; Nanoscience & Nanotechnology SC Engineering; Science & Technology - Other Topics GA V33LD UT WOS:000209019400003 PM 16281110 ER PT J AU Tellez, CM Cole, KD AF Tellez, CM Cole, KD TI Method for the characterization of size-exclusion chromatography media for preparative purification of DNA restriction fragments SO BIOTECHNOLOGY TECHNIQUES LA English DT Article DE chromatography; DNA; preparative; restriction fragments; size exclusion ID SEPARATION; PROTEINS AB A protocol has been developed to characterize the potential of size exclusion chromatography media for the separation of DNA fragments at a preparative scale. A standard DNA mixture composed of lambda-DNA cut with the restriction enzymes, AluI and HaeIII, was chromatographed on a column packed with the gel of interest. Fractions were collected and examined by PAGE. A digitized image of the gel was analyzed with the aid of a computer software program to determine the DNA fractionation range and selectivity curve for each chromatography gel. Four gels were characterized using this protocol. The effect of the elution buffer ionic strength on the fractionation of DNA was also investigated. C1 Univ Illinois, Dept Mech & Ind Engn, Urbana, IL 61801 USA. NIST, Div Biotechnol, Bioproc Engn Grp, Gaithersburg, MD 20899 USA. RP Cole, KD (reprint author), NIST, Div Biotechnol, Bioproc Engn Grp, 100 Bur Dr Stop 8312, Gaithersburg, MD 20899 USA. NR 12 TC 3 Z9 3 U1 2 U2 3 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0951-208X J9 BIOTECHNOL TECH JI Biotechnol. Tech. PD JUN PY 1999 VL 13 IS 6 BP 395 EP 401 DI 10.1023/A:1008932407733 PG 7 WC Biochemical Research Methods; Biotechnology & Applied Microbiology SC Biochemistry & Molecular Biology; Biotechnology & Applied Microbiology GA 213GZ UT WOS:000081265500009 ER PT J AU Schmidlin, TW Kosarik, J AF Schmidlin, TW Kosarik, J TI A record Ohio snowfall during 9-14 November 1996 SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article ID MICHIGAN AB A 6-day lake effect snow event produced a reported 68.9 in. (175.0 cm) of snowfall in Hambden Township, Geauga County, Ohio, during 9-14 November 1996. This exceeded the previous Ohio single-storm snowfall record of 42 in. The purpose of this research is to describe the meteorological situation that caused the record snowfall, document the site of the record snow and the methods of the measurement, describe the societal impacts of the storm, and assess the validity of the record. A persistent deep trough in the midtroposphere provided cold advection across Lake Erie into northeast Ohio. This combined with a very unstable lower atmosphere to allow deep, moist convection and a prolonged period of heavy snowfall. The observer and site were selected in 1993 for a federal study of lake effect snowfalls and the observer was a "snow spotter" for the National Weather Service office in Cleveland in November 1996. A review of snowfall data from the event indicates the reported snowfall is consistent with respect to snow depths, nearby reported snowfall, the synoptic situation, and societal impacts of the snow. The authors suggest the 68.9 in. of snowfall should be accepted as a new state record single-storm snowfall. In addition, the 76.7 in. (195 cm) of snowfall recorded at this site in November 1996 is a new monthly snowfall record for Ohio. C1 Kent State Univ, Dept Geog, Kent, OH 44242 USA. NOAA, Natl Weather Serv, Cleveland, OH USA. RP Schmidlin, TW (reprint author), Kent State Univ, Dept Geog, Kent, OH 44242 USA. NR 17 TC 11 Z9 14 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 JUN PY 1999 VL 80 IS 6 BP 1107 EP 1116 DI 10.1175/1520-0477(1999)080<1107:AROSDN>2.0.CO;2 PG 10 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 214RD UT WOS:000081340600004 ER PT J AU Wu, XQ Menzel, WP Wade, GS AF Wu, XQ Menzel, WP Wade, GS TI Estimation of sea surface temperatures using GOES-8/9 radiance measurements SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article ID TRACK SCANNING RADIOMETER; ENVIRONMENTAL SATELLITES; NEW-GENERATION; VALIDATION; OCEAN AB Sea surface temperatures (SSTs) are derived using measurements from the new generation of imaging instruments on the Geostationary Operational Environmental Satellites (GOES). The National Environmental Satellite, Data and Information Service has been producing hourly GOES SST estimates since December 1998. This paper presents the algorithm for cloud detection and atmospheric moisture correction and shows some initial results. Several advantages of GOES SST are evident in comparison with SST from polar orbiting satellites. Frequent sampling by GOES imagers results in a more complete map of SST as clouds move away. Changes in scene temperature over a short period of time help to detect the presence of clouds. The abundance of GOES observations enables stringent screening for cloud-free observations while maintaining good spatial coverage of clear-sky inferences of SST. Diurnal variations of SST over large areas are observed for the first time and their implications for numerical weather prediction and climate monitoring are discussed. C1 Univ Wisconsin, Ctr Space Sci & Engn, Cooperat Inst Meteorol Satellite Studies, Madison, WI 53706 USA. NOAA, NESDIS, Off Res & Applicat, Adv Satellite Prod Team, Madison, WI USA. RP Wu, XQ (reprint author), Univ Wisconsin, Ctr Space Sci & Engn, Cooperat Inst Meteorol Satellite Studies, 1225 W Dayton St, Madison, WI 53706 USA. RI Wu, Xiangqian/F-5634-2010; Menzel, W. Paul/B-8306-2011; Wade, Gary S./F-5630-2010 OI Wu, Xiangqian/0000-0002-7804-5650; Menzel, W. Paul/0000-0001-5690-1201; NR 24 TC 63 Z9 66 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 1999 VL 80 IS 6 BP 1127 EP 1138 DI 10.1175/1520-0477(1999)080<1127:EOSSTU>2.0.CO;2 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 214RD UT WOS:000081340600006 ER PT J AU Hoff, GR AF Hoff, GR TI Range extensions of 3 species of macrourids from the west coast of North America SO CALIFORNIA FISH AND GAME LA English DT Article C1 NOAA, Natl Marine Fisheries Serv, Resource Assessment & Conservat Engn Div, Alaska Fisheries Sci Ctr, Seattle, WA 98115 USA. RP Hoff, GR (reprint author), NOAA, Natl Marine Fisheries Serv, Resource Assessment & Conservat Engn Div, Alaska Fisheries Sci Ctr, 7600 Sand Point Way NE,Bldg 4,BIN C15700, Seattle, WA 98115 USA. NR 4 TC 3 Z9 3 U1 1 U2 1 PU CALIF FISH AND GAME EDITOR PI SACRAMENTO PA 1416 NINTH ST, SACRAMENTO, CA 95814 USA SN 0008-1078 J9 CALIF FISH GAME JI Calif. Fish Game PD SUM PY 1999 VL 85 IS 3 BP 113 EP 117 PG 5 WC Fisheries; Zoology SC Fisheries; Zoology GA 317JW UT WOS:000087223100003 ER PT J AU Trelles, J McGrattan, KB Baum, HR AF Trelles, J McGrattan, KB Baum, HR TI Smoke transport by sheared winds SO COMBUSTION THEORY AND MODELLING LA English DT Article ID BUOYANCY-DRIVEN PLUMES; COMPUTATIONAL MODEL; STRATIFIED ATMOSPHERE; DISPERSION; RISE; FIRES AB The effect that the wind's vertical variation has on fire plume behaviour is investigated. A parabolized set of governing equations are discretized using finite differences to arrive at the numerical model. Lagrangian particles are used to visualize the how, account for atmospheric fluctuations and determine the smoke concentration field. A parametric study based on varying the wind lapse rate is performed. Four cases from actual soundings are analysed with both the actual and an averaged constant wind. The results suggest that an increasing wind profile suppresses plume dynamics, leading to decreased plume rise heights. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Trelles, J (reprint author), Hughes Associates Inc, 3610 Commerce Dr,Suite 817, Baltimore, MD 21227 USA. NR 14 TC 6 Z9 7 U1 1 U2 2 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 1999 VL 3 IS 2 BP 323 EP 341 DI 10.1088/1364-7830/3/2/307 PG 19 WC Thermodynamics; Energy & Fuels; Engineering, Chemical; Mathematics, Interdisciplinary Applications SC Thermodynamics; Energy & Fuels; Engineering; Mathematics GA 217RV UT WOS:000081513500007 ER PT J AU Butler, P AF Butler, P TI Shear induced structures and transformations in complex fluids SO CURRENT OPINION IN COLLOID & INTERFACE SCIENCE LA English DT Review DE complex fluids; shear; shear-induced structures; scattering ID ANGLE NEUTRON-SCATTERING; DIBLOCK COPOLYMER GEL; CENTERED-CUBIC PHASE; LIQUID-CRYSTALLINE POLYMERS; WORMLIKE MICELLES; TRIBLOCK COPOLYMER; LAMELLAR PHASE; MOLECULAR-ORIENTATION; SURFACTANT MIXTURES; NEMATIC TRANSITION AB Shear induces a wide variety of structural transformations in complex fluids. The complexity of the subject guarantees that this will remain an active field for some time to come. A brief review of the current literature on the subject is given, and an attempt to extract general or unifying themes is made. Some general trends and weaknesses in the direction of current research are identified and suggestions made. Published by Elsevier Science Ltd. C1 NIST, Gaithersburg, MD 20899 USA. RP Butler, P (reprint author), NIST, Route 270 & Quince Orchard,Bldg 235,Rm E151, Gaithersburg, MD 20899 USA. RI Butler, Paul/D-7368-2011 NR 89 TC 77 Z9 79 U1 1 U2 14 PU ELSEVIER SCIENCE LONDON PI LONDON PA 84 THEOBALDS RD, LONDON WC1X 8RR, ENGLAND SN 1359-0294 J9 CURR OPIN COLLOID IN JI Curr. Opin. Colloid Interface Sci. PD JUN PY 1999 VL 4 IS 3 BP 214 EP 221 DI 10.1016/S1359-0294(99)00041-2 PG 8 WC Chemistry, Physical SC Chemistry GA 244WK UT WOS:000083073600008 ER PT J AU Bertram, MA Cowen, JP AF Bertram, MA Cowen, JP TI Temporal variations in the deep-water colonization rates of small benthic foraminifera: the results of an experiment on Cross Seamount SO DEEP-SEA RESEARCH PART I-OCEANOGRAPHIC RESEARCH PAPERS LA English DT Article ID NORTHEAST ATLANTIC; RAPID GROWTH; SEA; PHYTODETRITUS; VARIABILITY; DEPOSITION; MORPHOLOGY; ORGANISMS; COMMUNITY; OCEAN AB Modern benthic foraminifera are important remineralizers of organic matter and a link between surface-ocean production and life in the deep sea. Assemblages of benthic foraminifera are preserved in the fossil record, providing clues to paleoceanographic conditions. These clues can be fully interpreted only when our knowledge of the biology and ecology of modern species is more complete. To study factors influencing foraminiferal colonization rates, artificial substrates were placed on Cross Seamount (18 degrees 40'N, 158 degrees 17'W) for 1 to 42 months between 1989 and 1994. The colonization rates of benthic foraminifera onto different substrates (five mineral types were used) at four water depths (800, 975, 1285 and 2000 m) were determined. Both calcareous and agglutinated foraminifera inhabited these artificial substrates at different rates. Many of the agglutinated forms colonized at a uniform rate through time. The colonization rates of other foraminifera, primarily calcareous forms, were not constant through time, nor could the variability be attributed to the controlled variables (water depth and substrate composition). Instead, these temporal variations in colonization rate corresponded with shifts in surface ocean conditions and export fluxes in the central Pacific. Other ecological observations are also presented, including size- and spatial-distributions. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Univ Hawaii Manoa, Sch Ocean & Earth Sci & Technol, Dept Oceanog, Honolulu, HI 96822 USA. RP Bertram, MA (reprint author), NOAA, Pacific Marine Environm Lab, 7600 Sand Point Way Ne, Seattle, WA 98115 USA. NR 49 TC 18 Z9 18 U1 1 U2 5 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0967-0637 J9 DEEP-SEA RES PT I JI Deep-Sea Res. Part I-Oceanogr. Res. Pap. PD JUN PY 1999 VL 46 IS 6 BP 1021 EP 1049 DI 10.1016/S0967-0637(98)00104-6 PG 29 WC Oceanography SC Oceanography GA 198WE UT WOS:000080446600004 ER PT J AU Shima, M Salamanca-Riba, L Moffat, TP AF Shima, M Salamanca-Riba, L Moffat, TP TI Dissolution dynamics of artificially structured materials SO ELECTROCHEMICAL AND SOLID STATE LETTERS LA English DT Article ID ELECTRODEPOSITED CO/CU MULTILAYERS; GIANT MAGNETORESISTANCE; SYMMETRY AB The anodic dissolution of an ultrathin cobalt film buried beneath a copper overlayer has been studied using voltammetry and chronoamperometry. The films were produced by sequential electrodeposition of cobalt and copper layers from a solution of 1.5 mol/L CoSO4, 0.5 mol/L H3BO3, and 0.008 mol/L CuSO4. Subsequent stripping analysis was performed in the same electrolyte. The blocking efficiency of the copper overlayer was a strong function of its thickness and the stripping potential. Furthermore, the inhibition provided by the copper overlayer was found to be quite sensitive to the thickness of the buried cobalt layer. For copper overlayers between 13 and 29 monolayer equivalents of charge (MEQ) a sharp transition in the dissolution behavior of the buried cobalt layer was observed. Namely, negligible dissolution was observed if the cobalt layer was less than 30 MEQ while almost complete dissolution occurred when the cobalt layer was thicker than 45 MEQ. These experiments provide guidance in selecting appropriate processing parameters for electrodeposition of Cu/Co multilayers and simultaneously provide a sensitive measure of the defect structure of such films. (C) 1999 The Electrochemical Society. S1099-0062(98)11-003-9. All rights reserved. C1 Univ Maryland, Dept Mat & Nucl Engn, College Pk, MD 20742 USA. NIST, Mat Sci & Engn Lab, Gaithersburg, MD 20899 USA. RP Shima, M (reprint author), Univ Maryland, Dept Mat & Nucl Engn, College Pk, MD 20742 USA. RI Salamanca-Riba, Lourdes/B-3785-2009 OI Salamanca-Riba, Lourdes/0000-0001-8155-6403 NR 16 TC 11 Z9 11 U1 0 U2 2 PU ELECTROCHEMICAL SOC INC PI PENNINGTON PA 65 SOUTH MAIN STREET, PENNINGTON, NJ 08534 USA SN 1099-0062 J9 ELECTROCHEM SOLID ST JI Electrochem. Solid State Lett. PD JUN PY 1999 VL 2 IS 6 BP 271 EP 274 DI 10.1149/1.1390808 PG 4 WC Electrochemistry; Materials Science, Multidisciplinary SC Electrochemistry; Materials Science GA 187VG UT WOS:000079808300007 ER PT J AU Jovic, BM Jovic, VD Stafford, GR AF Jovic, BM Jovic, VD Stafford, GR TI Cyclic voltammetry on Ag(111) and Ag(100) faces in sodium hydroxide solutions SO ELECTROCHEMISTRY COMMUNICATIONS LA English DT Article DE silver single crystals; adsorption; charge transfer; phase transformation; Frumkin isotherm; silver oxide ID ELECTROCHEMICAL DOUBLE-LAYER; RAMAN-SPECTROSCOPY; SILVER ELECTRODES; ADSORPTION; OXIDE; MECHANISM; NUCLEATION; ABSORPTION; INTERFACE; OXIDATION AB The electrochemical behavior of silver (100) and (111) single crystal surfaces was examined by cyclic voltammetry in aqueous NaOH solution. In the 'double layer' region (between - 1.2 and 0.1 V (SCE)) adsorption of OH- ions followed by phase transformation into an Ag-OH monolayer was found to take place, The difference in peak potentials recorded in 0.1 and 0.01 mol dm(-3) NaOH solutions of about 60 mV indicate that one electron is exchanged in the overall electrochemical reaction, implying a complete charge transfer between OH- ions and the silver surface. The adsorption process has been modeled to a Frumkin adsorption isotherm. Further oxidation of silver into Ag2O takes place at more positive potentials. The formation of bulk Ag2O results in considerable change to the original single crystal surface. This is likely to bt: due to roughening of the silver surface as a consequence of the formation and reduction of the oxide. (C) 1999 Elsevier Science S.A. All rights reserved. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Jovic, VD (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NR 25 TC 55 Z9 56 U1 2 U2 17 PU ELSEVIER SCIENCE INC PI NEW YORK PA 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 USA SN 1388-2481 J9 ELECTROCHEM COMMUN JI Electrochem. Commun. PD JUN PY 1999 VL 1 IS 6 BP 247 EP 251 DI 10.1016/S1388-2481(99)00049-1 PG 5 WC Electrochemistry SC Electrochemistry GA 240UZ UT WOS:000082846300011 ER PT J AU O'Connell, CD Atha, DH Oldenburg, MC Tian, JX Siebert, M Handrow, R Grooms, K Heisler, L de Arruda, M AF O'Connell, CD Atha, DH Oldenburg, MC Tian, JX Siebert, M Handrow, R Grooms, K Heisler, L de Arruda, M TI Detection of p53 gene mutation: Analysis by single-strand conformation polymorphism and Cleavase fragment length polymorphism SO ELECTROPHORESIS LA English DT Article DE DNA standards; p53 mutation detection; slab-gel electrophoresis; single-strand conformation polymorphism; Cleavase (R) fragment length polymorphism ID BREAST-CANCER PATIENTS; POINT MUTATIONS; MYCOBACTERIUM-TUBERCULOSIS; CAPILLARY-ELECTROPHORESIS; PROGNOSTIC VALUE; DNA; SSCP; RESISTANCE; LONG; GEL AB We have generated a collection of clones containing single point mutations within the exon 5-9 hot spot regions of the p53 gene by using polymerase chain reaction (PCR) to amplify select regions of the gene from characterized cell lines. These clones were then used to address the sensitivity of mutation detection using slab-gel single-strand conformation polymorphism (SSCP) and Cleavase fragment length polymorphism (CFLP) assay systems. Both methods exhibited high sensitivities for the detection of mutations in cloned p53 mutations in this study: 97% for CFLP and 94% for SSCP. In addition to resulting in higher sensitivity of mutation detection, CFLP has the capability to analyze longer fragments. In this study, CFLP identified five intronic mutations which were not investigated in the exon-specific SSCP assay. These results agree with those found elsewhere and demonstrate that CFLP scanning can have practical advantages when used for the identification of sequence alterations within the p53 gene. C1 NIST, Div Biotechnol, Gaithersburg, MD 20899 USA. Third Wave Technol, Madison, WI USA. RP O'Connell, CD (reprint author), NIST, Div Biotechnol, Bldg 227,Rm A243,Mailstop 8311, Gaithersburg, MD 20899 USA. NR 23 TC 19 Z9 19 U1 0 U2 1 PU WILEY-V C H VERLAG GMBH PI BERLIN PA MUHLENSTRASSE 33-34, D-13187 BERLIN, GERMANY SN 0173-0835 J9 ELECTROPHORESIS JI Electrophoresis PD JUN PY 1999 VL 20 IS 6 BP 1211 EP 1223 DI 10.1002/(SICI)1522-2683(19990101)20:6<1211::AID-ELPS1211>3.0.CO;2-7 PG 13 WC Biochemical Research Methods; Chemistry, Analytical SC Biochemistry & Molecular Biology; Chemistry GA 202LQ UT WOS:000080654100012 PM 10380761 ER PT J AU Reichert, WL French, BL Stein, JE AF Reichert, WL French, BL Stein, JE TI Exposure of marine mammals to genotoxic environmental contaminants: Application of the P-32-postlabeling assay for measuring DNA-xenobiotic adducts SO ENVIRONMENTAL MONITORING AND ASSESSMENT LA English DT Article DE biomarkers; DNA adducts; marine mammals; PAHs; polycyclic aromatic compounds ID POLYCYCLIC AROMATIC-HYDROCARBONS; P-32 POSTLABELING ANALYSIS; NORTHWEST ATLANTIC; BELUGA WHALES; ST-LAWRENCE; TISSUE; LIVER; FISH; SENSITIVITY; PERSISTENCE AB There is little information on exposure of marine mammals to genotoxic environmental contaminants. The P-32-postlabeling assay has been successfully used to assess exposure to genotoxic polycyclic aromatic compounds in fish and humans. In the present study, a preliminary investigation showed that polycyclic aromatic compound-like DNA adducts were present in hepatic tissues of harbor seals (Phoca vitulina richardsi) exposed to petroleum following the Exxon Valdez oil spill. However, for marine mammals, effects from changes in tissue condition on DNA recovery and quality is of concern, because tissue samples are often collected from animals that have been dead for unknown periods of time. To assess the effects of postmortem thermal history on DNA recovery from tissue and on DNA adduct quantitation, samples of harbor porpoise (Phocoena phocoena) hepatic tissue were incubated for up to 10 d at 4 and 30 degrees C. Only traces (<4 mu g) of hepatic DNA were recovered from 200 mg of tissue after incubation at 30 degrees C for 36 h. At 4 degrees C, DNA (50-130 mu g) was recovered from tissue incubated for up to 6 d; whereas DNA recovery at 10 d was minimal. Chromatograms of P-32-labeled DNA digests of liver tissue held at 4 and 30 degrees C and salmon sperm DNA held at 30 degrees C for 2 d had comparable profiles, suggesting that alteration of DNA bases had occurred during incubation of porpoise liver tissue. Moreover, the chromatograms of DNA extracted from liver tissues of harbor porpoises caught incidentally in a northwest Atlantic fishery, packed in ice and sampled several days later also exhibited similar altered DNA structures. Although, altered DNA structures that can interfere with the DNA adduct quantitation were present in autolyzed tissue, changes in the P-32-postlabeling chromatography conditions can decrease the interference. Moreover, in a study with tissues taken from California sea lions (Zalophus californianus) immediately postmortem and stored at -80 degrees C until processing, DNA structures associated with tissue breakdown were not observed. The DNA from sea lions, however, had putative age-dependent hepatic DNA modifications, which have a distinctive profile, and must be considered when evaluating exposure of marine mammals to polycyclic aromatic compounds. Overall, the findings showed that with attention to the postmortem thermal history of the tissue samples hepatic DNA adducts, as measured by P-32-postlabeling, have the potential to serve as a biological indicator of exposure of marine mammals to environmental genotoxic compounds. C1 NOAA, Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, Environm Conservat Div, Seattle, WA 98112 USA. RP Reichert, WL (reprint author), NOAA, Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, Environm Conservat Div, 2725 Montlake Blvd E, Seattle, WA 98112 USA. NR 39 TC 5 Z9 5 U1 2 U2 4 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0167-6369 J9 ENVIRON MONIT ASSESS JI Environ. Monit. Assess. PD JUN PY 1999 VL 56 IS 3 BP 225 EP 239 DI 10.1023/A:1005991116993 PG 15 WC Environmental Sciences SC Environmental Sciences & Ecology GA 203LU UT WOS:000080709800001 ER PT J AU Field, LJ MacDonald, DD Norton, SB Severn, CG Ingersoll, CG AF Field, LJ MacDonald, DD Norton, SB Severn, CG Ingersoll, CG TI Evaluating sediment chemistry and toxicity data using logistic regression modeling SO ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY LA English DT Article DE sediment toxicity; logistic regression; sediment-quality guidelines ID QUALITY GUIDELINES; MARINE AB This paper describes the use of logistic-regression modeling for evaluating matching sediment chemistry and toxicity data. Contaminant-specific logistic models were used to estimate the percentage of samples expected to be toxic at a given concentration. These models enable users to select the probability of effects of concern corresponding to their specific assessment or management objective or to estimate the probability of observing specific biological effects at any contaminant concentration. The models were developed using a large database (n = 2,524) of matching saltwater sediment chemistry and toxicity data for field-collected samples compiled from a number of different sources and geographic areas. The models for seven chemicals selected as examples showed a wide range in goodness of fit, reflecting high variability in toxicity at low concentrations and limited data on toxicity at higher concentrations for some chemicals. The models for individual test endpoints (e.g., amphipod mortality) provided a better fit to the data than the models based on all endpoints combined. A comparison of the relative sensitivity of two amphipod species to specific contaminants illustrated an important application of the logistic model approach. C1 NOAA, Off Response & Restorat, Seattle, WA 98115 USA. MacDonald Environm Sci Ltd, Ladysmith, BC V0R 2E0, Canada. US EPA, Natl Ctr Environm Assessment, Washington, DC 20460 USA. Evs Consultants Ltd, Seattle, WA 98119 USA. US Geol Survey, Columbia, MO 65201 USA. RP Field, LJ (reprint author), NOAA, Off Response & Restorat, 7600 Sand Point Way NE, Seattle, WA 98115 USA. NR 22 TC 40 Z9 43 U1 3 U2 10 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 JUN PY 1999 VL 18 IS 6 BP 1311 EP 1322 DI 10.1897/1551-5028(1999)018<1311:ESCATD>2.3.CO;2 PG 12 WC Environmental Sciences; Toxicology SC Environmental Sciences & Ecology; Toxicology GA 197YG UT WOS:000080393500034 ER PT J AU Meise, C Collie, JS Widman, J Howell, P AF Meise, C Collie, JS Widman, J Howell, P TI Growth and mortality of juvenile winter flounder in two New England estuaries SO ESTUARIES LA English DT Article ID LIFE-HISTORY DATA; PSEUDOPLEURONECTES-AMERICANUS; SOUND AB A length-based model for calculating growth and mortality of juvenile winter flounder (Pseudopleuronectes americanus) populations has been developed. This model is based on work by Sullivan et al. (1990) and incorporates the von Bertalanffy growth equation, including stochasticity in growth, and a mortality rate that decreases exponentially with size. The length-based model was fit to observed size-frequency distributions, and model likelihood profiles were generated to produce 95% confidence intervals about parameter estimates. We analyzed size-frequency distributions of 3 to 15 cm juvenile winter flounder, collected with a l-m beam trawl, at monthly intervals from June to October during 1993 and 1994. Growth rates were higher at a contaminated site, New Haven Harbor, than at a clean site, the Connecticut River estuary, however, the parameter estimates had overlapping 95% confidence intervals. Mortality rates were similar at the two sites. C1 Natl Marine Fisheries Serv, JJ Howard Lab, Highlands, NJ 07732 USA. Univ Rhode Isl, Grad Sch Oceanog, Narragansett, RI 02882 USA. Natl Marine Fisheries Serv, Milford Lab, Milford, CT 06460 USA. Marine Headquarters, Old Lyme, CT 06371 USA. RP Meise, C (reprint author), Natl Marine Fisheries Serv, JJ Howard Lab, 74 Magruder Rd, Highlands, NJ 07732 USA. NR 23 TC 8 Z9 8 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 1999 VL 22 IS 2A BP 297 EP 303 DI 10.2307/1352985 PG 7 WC Environmental Sciences; Marine & Freshwater Biology SC Environmental Sciences & Ecology; Marine & Freshwater Biology GA 236BN UT WOS:000082578500012 ER PT J AU Stumpf, RP Frayer, ML Durako, MJ Brock, JC AF Stumpf, RP Frayer, ML Durako, MJ Brock, JC TI Variations in water clarity and bottom albedo in Florida Bay from 1985 to 1997 SO ESTUARIES LA English DT Article ID HIGH-RESOLUTION RADIOMETER; MODERATELY TURBID ESTUARY; INNER-SHELF LAGOON; THALASSIA-TESTUDINUM; ATTENUATION COEFFICIENT; COASTAL WATERS; USA; CALIBRATION; VARIABILITY; SPACECRAFT AB Following extensive seagrass die-offs of the late 1980s and early 1990s, Florida Bay reportedly had significant declines in water clarity due to turbidity and algal blooms. Scant information exists on the extent of the decline, as this bay was not investigated for water quality concerns before the die-offs and limited areas were sampled after the primary die-off. We use imagery from the Advanced Very High Resolution Radiometer (AVHRR) to examine water clarity in Florida Bay for the period 1985 to 1997. The AVHRR provides data on nominal water reflectance and estimated light attenuation, which are used here to describe turbidity conditions in the bay on a seasonal basis. in situ observations on changes in seagrass abundance within the bay, combined with the satellite data, provide additional insights into losses of seagrass. The imagery shows an extensive region to the west of Florida Bay having increased reflectance and light attenuation in both winter and summer begining in winter of 1988. These increases are consistent with a change from dense seagrass to sparse or negligible cover. Approximately 200 km(2) of these offshore seagrasses may have been lost during the primary die-off (1988 through 1991), significantly more than in the bay, The imagery shows the distribution and timing of increased turbidity that followed the die-offs in the northwestern regions of the bay, exemplified in Rankin Lake and Johnson Key Basin, and indicates that about 200 km2 of dense seagrass may have been lost or severely degraded within the bay from the start of the die-off. The decline in water clarity has continued in the northwestern bay since 1991, The area west of the Everglades National Park boundaries has shown decreases in both winter turbidity and summer reflectances, suggestive of partial seagrass recovery. Areas of low reflectance associated with a major Syringodium filiforme seagrass meadow north of Marathon (Vaca Key in the Florida Keys) appear to have expanded westward toward Big Pine Key indicating changes in the bottom cover from before the die-off. The southern and eastern sections of the Bay have not shown significant changes in water clarity or bottom albedo throughout the entire time period. C1 US Geol Survey, Ctr Coastal Geol, St Petersburg, FL 33701 USA. Florida Marine Res Inst, Florida Dept Enviornm Protect, St Petersburg, FL 33701 USA. RP Stumpf, RP (reprint author), NOAA, Natl Ocean Serv, 1305 East West Highway,Room 10110, Silver Spring, MD 20910 USA. NR 30 TC 27 Z9 30 U1 1 U2 7 PU ESTUARINE RES FEDERATION PI LAWRENCE PA PO BOX 368, LAWRENCE, KS 66044 USA SN 0160-8347 J9 ESTUARIES JI Estuaries PD JUN PY 1999 VL 22 IS 2B BP 431 EP 444 DI 10.2307/1353209 PG 14 WC Environmental Sciences; Marine & Freshwater Biology SC Environmental Sciences & Ecology; Marine & Freshwater Biology GA 236BP UT WOS:000082578600007 ER PT J AU Browder, JA Restrepo, VR Rice, JK Robblee, MB Zein-Eldin, Z AF Browder, JA Restrepo, VR Rice, JK Robblee, MB Zein-Eldin, Z TI Environmental influences on potential recruitment of pink shrimp, Farfantepenaeus duorarum, from Florida Bay nursery grounds SO ESTUARIES LA English DT Article ID TORTUGAS GROUNDS; PENAEUS-DUORARUM AB Two modeling approaches were used to explore the basis for variation in recruitment of pink shrimp, Farfantepenaeus duorarum, to the Tortugas fishing grounds. Emphasis was on development and juvenile densities on the nursery grounds. An exploratory simulation modeling exercise demonstrated large year-to-year variations in recruitment contributions to the Tortugas pink shrimp fishery may occur on some nursery grounds, and production may differ considerably among nursery grounds within the same year, simply on the basis of differences in temperature and salinity. We used a growth and survival model to simulate cumulative harvests from a July-centered cohort of early-settlement-stage postlarvae from two parts of Florida Bay (western Florida Bay and northcentral Florida Bay), using historic temperature and salinity data from these areas. Very large year-to-year differences in simulated cumulative harvests were found for recruits from Whipray Basin. Year-to-year differences in simulated harvests of recruits from Johnson Key Basin were much smaller. In a complementary activity, generalized Linear and additive models and intermittent, historic density records were used to develop an uninterrupted multi-year time series of monthly density estimates for juvenile pink shrimp in the Johnson Key Basin. The developed data series was based on relationships of density with environmental variables. The strongest relationship was with sea-surface temperature. Three other environmental variables (rainfall, water level at Everglades National Park Well P35, and mean wind speed) also contributed significantly to explaining variation in juvenile densities. Results of the simulation model and two of the three statistical models yielded similar interannual patterns for Johnson Key Basin. While it is not possible to say that one result validates the other, the concordance of the annual patterns from the two models is supportive of both approaches. C1 NOAA, SE Fisheries Sci Ctr, Natl Marine Fisheries Serv, Miami, FL 33149 USA. Univ Miami, Rosenstiel Sch Marine & Atmospher Sci, Cooperat Unit Fisheries Educ & Res, Miami, FL 33149 USA. Florida Int Univ, US Geol Survey, Florida Caribbean Sci Ctr, Biol Res Div, Miami, FL 33199 USA. NOAA, SE Fisheries Sci Ctr, Natl Marine Fisheries Serv, Galveston, TX 77550 USA. RP Browder, JA (reprint author), NOAA, SE Fisheries Sci Ctr, Natl Marine Fisheries Serv, 75 Virginia Beach Dr, Miami, FL 33149 USA. EM joan.browder@noaa.gov NR 38 TC 24 Z9 25 U1 1 U2 6 PU ESTUARINE RESEARCH FEDERATION PI PORT REPUBLIC PA 2018 DAFFODIL, PO BOX 510, PORT REPUBLIC, MD 20676 USA SN 0160-8347 J9 ESTUARIES JI Estuaries PD JUN PY 1999 VL 22 IS 2B BP 484 EP 499 DI 10.2307/1353213 PG 16 WC Environmental Sciences; Marine & Freshwater Biology SC Environmental Sciences & Ecology; Marine & Freshwater Biology GA 236BP UT WOS:000082578600011 ER PT J AU Thayer, GW Powell, AB Hoss, DE AF Thayer, GW Powell, AB Hoss, DE TI Composition of larval, juvenile, and small adult fishes relative to changes in environmental conditions in Florida Bay SO ESTUARIES LA English DT Article ID SNAPPER LUTJANUS-GRISEUS; EARLY LIFE-HISTORY; THALASSIA-TESTUDINUM; CYNOSCION-NEBULOSUS; SPOTTED SEATROUT; GRAY SNAPPER; SEAGRASS BEDS; FOOD-HABITS; TAMPA-BAY; DIE-OFF AB We compared (1) ichthyoplankton composition and (2) basin and channel habitat ichthyofauna and sea grass densities between 1984-1985 and 1994-1996 in Florida Bay. Stations and sampling techniques employed in 1984-1985 were duplicated in the 1994-1996 study. Thalassia testudinum, Halodule wrightii, and Syringodium filiforme densities within most of the basin and channel strata sampled in 1994-1996 had decreased by as much as 100%. We did not observe changes in the total density of juvenile and small adult fishes coincident with the reductions in seagrass densities except in the deepwater channel habitats. There was an increase in the proportion of the total ichthyofauna represented by pelagic atherinids, engraulids, and clupeids, particularly the engraulid Anchoa mitchilli, and a concomitant decrease in the proportion represented by canopy-dwelling and morebenthic-dwelling seagrass inhabitants. This suggested a shift toward a planktonic-feeding community. We observed an increase in the density and frequency of engraulid larvae, particularly in the western and Gulf of Mexico portions of Florida Bay, but no significant changes in densities of the commonly collected ichthyoplankton that are demersal as adults (i.e., Gobiidae, Callionymidae, and Blennioidei). Lucania parva Eucinostomus spp, Lagodon rhomboides, Floridichthys carpio, Haemulon plumieri, and Syngnathus floridae represented nearly 86% of the juvenile and small adult fish collected in 1984-1985 but represented only 29% of the ichthyofauna a decade later. The distribution of juvenile spotted seatrout had expanded into the central and northeastern basins of our sampling area, perhaps in response to reduced salinities or to the availability of food resources. C1 Natl Ocean Serv, US Dept Commerce, Ctr Coastal Fisheries & Habitat Res, Beaufort Lab, Beaufort, NC 28516 USA. RP Thayer, GW (reprint author), Natl Ocean Serv, US Dept Commerce, Ctr Coastal Fisheries & Habitat Res, Beaufort Lab, 101 Pivers Isl Rd, Beaufort, NC 28516 USA. NR 45 TC 50 Z9 51 U1 1 U2 14 PU ESTUARINE RES FEDERATION PI LAWRENCE PA PO BOX 368, LAWRENCE, KS 66044 USA SN 0160-8347 J9 ESTUARIES JI Estuaries PD JUN PY 1999 VL 22 IS 2B BP 518 EP 533 DI 10.2307/1353215 PG 16 WC Environmental Sciences; Marine & Freshwater Biology SC Environmental Sciences & Ecology; Marine & Freshwater Biology GA 236BP UT WOS:000082578600013 ER PT J AU Peacock, RD Reneke, PA Bukowski, RW Babrauskas, V AF Peacock, RD Reneke, PA Bukowski, RW Babrauskas, V TI Defining flashover for fire hazard calculations SO FIRE SAFETY JOURNAL LA English DT Article ID MODEL; SMOKE AB As the use of performance-based methods for evaluating the fire behavior of materials and systems becomes more widespread, objective criteria to judge fire behavior become more important. This paper reviews techniques for predicting the most common of these criteria, the onset of flashover. The experimental basis for working definitions of flashover is reviewed. Comparisons of available calculational procedures ranging from simple correlations to computer-based fire models that can be used to estimate flashover are presented. Although the techniques range in complexity and results, the various predictions give estimates commensurate with the precision of available experimental data. (C) 1999 Published by Elsevier Science Ltd. All rights reserved. C1 NIST, Bldg & Fire Res Lab, Gaithersburg, MD 20899 USA. Fire Sci & Technol Inc, Issaquah, WA 98027 USA. RP Peacock, RD (reprint author), NIST, Bldg & Fire Res Lab, Gaithersburg, MD 20899 USA. NR 46 TC 32 Z9 42 U1 0 U2 4 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0379-7112 J9 FIRE SAFETY J JI Fire Saf. J. PD JUN PY 1999 VL 32 IS 4 BP 331 EP 345 DI 10.1016/S0379-7112(98)00048-4 PG 15 WC Engineering, Civil; Materials Science, Multidisciplinary SC Engineering; Materials Science GA 191XL UT WOS:000080047000003 ER PT J AU Brodeur, RD Terazaki, M AF Brodeur, RD Terazaki, M TI Springtime abundance of chaetognaths in the shelf region of the northern Gulf of Alaska, with observations on the vertical distribution and feeding of Sagitta elegans SO FISHERIES OCEANOGRAPHY LA English DT Article DE chaetognaths; distribution; food habits; growth; Gulf of Alaska; Sagitta elegans ID AGE-0 WALLEYE POLLOCK; OCEAN STATION-P; OF-ALASKA; INVERTEBRATE PREDATORS; THERAGRA-CHALCOGRAMMA; ZOOPLANKTON; MIGRATION; EGGS; BEHAVIOR; VERRILL AB Chaetognatha were among the most dominant macrozooplankton taxa collected in 6 years of springtime collections, both throughout the water column and near-bottom on the continental shelf in the northern Gulf of Alaska. Three species (Sagitta elegans, S. scrippsae, and Eukrohnia hamata) were collected in 248 collections, although S. elegans was the numerically dominant species overall during most cruises. Collections taken in epibenthic sleds generally contained about two orders of magnitude more chaetognaths than those that sampled throughout the water column. Two size modes were apparent in the S. elegans size-frequency distributions which were believed to belong to different cohorts. Growth rate was on the order of 2-3 mm per month. The two cohorts showed asynchronous diel vertical distribution patterns, with the smaller individuals found near the surface during the day whereas the larger individuals were near the surface at night. About 7.5% of the S. elegans examined contained food. Copepods made up the majority (similar to 89% by number) of the diet of both large and small individuals. Euphausiid juveniles and cirripede larvae were also observed, as well as several incidences of cannibalism by large chaetognaths on smaller individuals. Based on the results of two diel series, this species was observed to feed mainly during the night-time. C1 Alaska Fisheries Sci Ctr, Seattle, WA 98115 USA. Univ Tokyo, Ocean Res Inst, Nakano Ku, Tokyo 164, Japan. RP Brodeur, RD (reprint author), Alaska Fisheries Sci Ctr, 7600 Sand Point Way NE, Seattle, WA 98115 USA. NR 41 TC 20 Z9 20 U1 0 U2 3 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 1999 VL 8 IS 2 BP 93 EP 103 DI 10.1046/j.1365-2419.1999.00099.x PG 11 WC Fisheries; Oceanography SC Fisheries; Oceanography GA 262TA UT WOS:000084081500002 ER PT J AU Wilderbuer, TK Zhang, CI AF Wilderbuer, TK Zhang, CI TI Evaluation of the population dynamics and yield characteristics of Alaska plaice, Pleuronectes quadrituberculatus, in the eastern Bering Sea SO FISHERIES RESEARCH LA English DT Article DE Alaska plaice; fisheries management; bottom trawl survey; age structured model; production model ID GROWTH; MORTALITY; BIOMASS AB Alaska plaice, Pleuronectes quadrituberculatus, are one of the major shallow water flatfish species in the eastern Bering Sea ecosystem. It is most highly concentrated in the shallow continental shelf waters of the eastern Bering Sea. The stock has been lightly exploited and annual commercial catches have ranged from less than 1000 metric ton (t) in 1963 to 62 000 t in 1988. Current stock assessments have characterized the resource as being in a high and stable condition. However, these assessments have relied mainly upon the time-series of demersal trawl surveys conducted annually in the eastern Bering Sea. We extend the assessment of this species through the use of age-structured models such as stock synthesis analysis and biomass-based models using all available catch and survey information. These age-structured models indicate that the stock biomass has steadily declined from a peak level in the early 1980s due to a lack of recruitment, Optimum yield and age at first capture are examined and important management parameters are estimated (MSY, B-MSY, F-MSY) Finally, appropriate future harvest strategies are investigated under a range of possible fishing intensity levels. (C) 1999 Elsevier Science B.V. All rights reserved. C1 NOAA, Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr, REFM Div, Seattle, WA 98115 USA. Pukyung Natl Univ, Pusan 608737, South Korea. RP Wilderbuer, TK (reprint author), NOAA, Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr, REFM Div, 7600 Sand Point Way NE,Bld 4, Seattle, WA 98115 USA. NR 23 TC 1 Z9 1 U1 0 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 JUN PY 1999 VL 41 IS 2 BP 183 EP 200 DI 10.1016/S0165-7836(99)00012-0 PG 18 WC Fisheries SC Fisheries GA 197PU UT WOS:000080374700007 ER PT J AU Sengers, JMHL AF Sengers, JMHL TI Mean-field theories, their weaknesses and strength SO FLUID PHASE EQUILIBRIA LA English DT Article; Proceedings Paper CT 8th International Conference on Properties and Phase Equilibria for Product and Process Design CY APR 26-MAY 01, 1998 CL NOORDWIJKERHOUT, NETHERLANDS SP AKZO Nobel, Delft Univ Technol, DSM Res, Fac Appl Sci, TUDelf, Lab Appl Thermodynam & Phase Equilibria, TUDelft, Natl Sci Fdn USA, Purac Biochem, Shell Nederland BV, Solvay Pharmaceut, Unilever Res, Univ Fdn Delft DE critical state; equation of state; global phase diagrams; history; mixtures; supercritical fluids ID REDLICH-KWONG EQUATION; BINARY FLUID MIXTURES; GLOBAL PHASE-DIAGRAM; HARD-CHAIN THEORY; BEHAVIOR; STATE; EQUILIBRIA; MODEL; POINT AB Within a historical context, an evaluation of mean-field theory is given in its application to fluids and fluid mixtures. The way mean-field equations such as the Van der Waals equation incorporate molecular attraction and repulsion implies neglect of fluctuations. This neglect of both local and long-range structure is an impediment to characterizing liquids and supercritical fluids. In particular, mean-field theory is unable to describe critical behavior properly. This was known around 1900, but has been fully corrected only recently. The simplicity of mean-field equations is also their strong point. By 1905, most complexities of binary fluid phase diagrams known from experiment had been derived from the Van der Waals equation. Efforts to improve this equation have led to pathology in the global phase diagram. Paradoxically, it appears that increased sophistication leads to undesirable features in the phase diagrams. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Natl Inst Stand & Technol, Phys & Chem Properties Div, Gaithersburg, MD 20899 USA. RP Sengers, JMHL (reprint author), Natl Inst Stand & Technol, Phys & Chem Properties Div, Gaithersburg, MD 20899 USA. NR 50 TC 20 Z9 20 U1 1 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0378-3812 J9 FLUID PHASE EQUILIBR JI Fluid Phase Equilib. PD JUN PY 1999 VL 158 BP 3 EP 17 PG 15 WC Thermodynamics; Chemistry, Physical; Engineering, Chemical SC Thermodynamics; Chemistry; Engineering GA 207UY UT WOS:000080955200002 ER PT J AU Harrison, DE Vecchi, GA AF Harrison, DE Vecchi, GA TI On the termination of El Nino SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID SEA-SURFACE TEMPERATURE; TROPICAL PACIFIC; SOUTHERN OSCILLATION; EVENTS; MODEL; WINDS; ENSO AB A. feature of the end-phase of recent El Nino periods is thermocline shallowing to normal depths, in the central and eastern equatorial Pacific, before sea surface temperature (SST) returns to normal. Also characteristic of El Nino periods is a late-in-the-year shift of the El Nino equatorial westerly wind anomalies, from symmetric about the equator to centered south of the equator. We show that the directly forced ocean response to this shift produces thermocline shallowing like that observed. The wind shift may result from the normal seasonal evolution of Pacific waters warmer than 28 degrees C. These shift from being relatively symmetric about the equator in October-November, to concentrated south of the equator in December-January. Thus, the seasonal cycle may be a central part of the mechanism of El Nino termination. C1 NOAA, Pacific Marine Environm Lab, Seattle, WA 98115 USA. Univ Washington, Joint Inst Study Atmosphere & Oceans, Seattle, WA 98115 USA. Univ Washington, Sch Oceanog, Seattle, WA 98195 USA. RP Harrison, DE (reprint author), NOAA, Pacific Marine Environm Lab, 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 20 TC 79 Z9 81 U1 2 U2 5 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JUN 1 PY 1999 VL 26 IS 11 BP 1593 EP 1596 DI 10.1029/1999GL900316 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 202PG UT WOS:000080660900021 ER PT J AU Murnane, RJ Sarmiento, JL Le Quere, C AF Murnane, RJ Sarmiento, JL Le Quere, C TI Spatial distribution of air-sea CO2 fluxes and the interhemispheric transport of carbon by the oceans SO GLOBAL BIOGEOCHEMICAL CYCLES LA English DT Article ID GENERAL-CIRCULATION-MODEL; ACID DISSOCIATION-CONSTANTS; PAST 2 CENTURIES; NORTH-ATLANTIC; ATMOSPHERIC CO2; WORLD OCEAN; TRACER DISTRIBUTIONS; CALCIUM-CARBONATE; BOMB RADIOCARBON; HEAT-TRANSPORT AB The dominant processes controlling the magnitude and spatial distribution of the preindustrial air-sea flux of CO2 are atmosphere-ocean heat exchange and the biological pump, coupled with the direct influence of ocean circulation resulting from the slow time-scale of air-sea CO2 gas exchange equilibration. The influence of the biological pump is greatest in surface outcrops of deep water, where the excess deep ocean carbon resulting from net remineralization can escape to the atmosphere. In a steady state other regions compensate for this loss by taking up CO2 to give a global net air-sea CO2 flux of zero. The predominant outcrop region is the Southern Ocean, where the loss to the atmosphere of biological pump CO2 is large enough to cancel the gain of CO2 due to cooling. The influence of the biological pump on uptake of anthropogenic CO2 is small: a model including biology takes up 4.9% less than a model without it. Our model does not predict the large southward interhemispheric transport of CO2 that has been suggested by atmospheric carbon transport constraints. C1 Bermuda Biol Stn Res, St Georges GE01, Bermuda. Princeton Univ, Dept Geosci, Program Atmospher & Ocean Sci, Princeton, NJ 08544 USA. Lab Sci Climat & Environm, F-91191 Gif Sur Yvette, France. RP Murnane, RJ (reprint author), Bermuda Biol Stn Res, Bat 701, St Georges GE01, Bermuda. EM rmurnane@bbsr.edu; jls@splash.princeton.edu; lequere@lsce.saclay.cea.fr RI Le Quere, Corinne/C-2631-2017 OI Le Quere, Corinne/0000-0003-2319-0452 NR 87 TC 62 Z9 66 U1 0 U2 7 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0886-6236 EI 1944-9224 J9 GLOBAL BIOGEOCHEM CY JI Glob. Biogeochem. Cycle PD JUN PY 1999 VL 13 IS 2 BP 287 EP 305 DI 10.1029/1998GB900009 PG 19 WC Environmental Sciences; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Geology; Meteorology & Atmospheric Sciences GA 213GQ UT WOS:000081264700003 ER PT J AU Gruber, N Keeling, CD Bacastow, RB Guenther, PR Lueker, TJ Wahlen, M Meijer, HAJ Mook, WG Stocker, TF AF Gruber, N Keeling, CD Bacastow, RB Guenther, PR Lueker, TJ Wahlen, M Meijer, HAJ Mook, WG Stocker, TF TI Spatiotemporal patterns of carbon-13 in the global surface oceans and the oceanic Suess effect SO GLOBAL BIOGEOCHEMICAL CYCLES LA English DT Article ID NINO SOUTHERN OSCILLATION; FOSSIL-FUEL CO2; EL-NINO; ISOTOPE FRACTIONATION; PLANKTON DELTA-C-13; ANTHROPOGENIC CO2; ATMOSPHERIC CO2; ATLANTIC-OCEAN; C-13; RECORD AB A global synthesis of the C-13/C-12 ratio of dissolved inorganic carbon (DIC) in the surface ocean is attempted by summarizing high-precision data obtained from 1978 to 1997 in all major ocean basins. The data, mainly along transects but including three subtropical time series, are accompanied by simultaneous, precise measurements of DIC concentration and titration alkalinity. The reduced isotopic ratio, delta(13)C, in the surface ocean water is governed by a balance between biological and thermodynamic processes. These processes have strongly opposing tendencies, which result in a complex spatial pattern in delta(13)C with relatively little variability. The most distinctive feature in the spatial distribution of delta(13)C seen in our data is a maximum of delta(13)C near the subantarctic front with sharply falling values to the south. We attribute this feature to a combination of biological uptake of CO2 depleted in C-13 (low delta(13)C) and air-sea exchange near the front and upwelling further south of waters with low delta(13)C resulting from the remineralization of organic matter. Additional features are maxima in delta(13)C downstream of upwelling regions, reflecting biological uptake, and minima in the subtropical gyres caused by strongly temperature dependent thermodynamic isotopic fractionation. At the time series stations, two in the North Atlantic Ocean and one in the North Pacific, distinct seasonal cycles in delta(13)C are observed, the Pacific data exhibiting only about half the amplitude of the Atlantic. Secular decreases in delta(13)C caused by the invasion of isotopically light anthropogenic CO2 into the ocean (the C-13 Suess effect) have been identified at these time series stations and also in data from repeated transects in the Indian Ocean and the tropical Pacific. A tentative global extrapolation of these secular decreases yields a surface oceanic C-13 Suess effect of approximately -0.018 parts per thousand yr(-1) from 1980 to 1995. This effect is nearly the same as the C-13 Suess effect observed globally in the atmosphere over the same period. We attribute this response to a deceleration in the growth rate of anthropogenic CO2 emissions after 1979, which subsequently has reduced the atmospheric C-13 Suess effect more than the surface ocean effect. C1 Princeton Univ, Atmospher & Ocean Sci Program, Princeton, NJ 08544 USA. Univ Calif San Diego, Scripps Inst Oceanog, La Jolla, CA 92093 USA. Univ Groningen, Centrum Isotopen Onderzoek, NL-9722 JX Groningen, Netherlands. Univ Bern, Inst Phys, CH-3012 Bern, Switzerland. RP Gruber, N (reprint author), Princeton Univ, Atmospher & Ocean Sci Program, Sayre Hall,Forrestal Campus,POB CN710, Princeton, NJ 08544 USA. EM gruber@splash.princeton.edu; cdkeeling@ucsd.edu; rbacastow@ucsd.edu; pguenther@ucsd.edu; tlueker@ucsd.edu; mwahlen@ucsd.edu; meijer@phys.rug.nl; stocker@climate.unibe.ch RI Gruber, Nicolas/B-7013-2009; Meijer, Harro/A-5787-2012; Stocker, Thomas/B-1273-2013 OI Gruber, Nicolas/0000-0002-2085-2310; NR 74 TC 142 Z9 143 U1 6 U2 55 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0886-6236 EI 1944-9224 J9 GLOBAL BIOGEOCHEM CY JI Glob. Biogeochem. Cycle PD JUN PY 1999 VL 13 IS 2 BP 307 EP 335 DI 10.1029/1999GB900019 PG 29 WC Environmental Sciences; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Geology; Meteorology & Atmospheric Sciences GA 213GQ UT WOS:000081264700004 ER PT J AU Kettle, AJ Andreae, MO Amouroux, D Andreae, TW Bates, TS Berresheim, H Bingemer, H Boniforti, R Curran, MAJ DiTullio, GR Helas, G Jones, GB Keller, MD Kiene, RP Leck, C Levasseur, M Malin, G Maspero, M Matrai, P McTaggart, AR Mihalopoulos, N Nguyen, BC Novo, A Putaud, JP Rapsomanikis, S Roberts, G Schebeske, G Sharma, S Simo, R Staubes, R Turner, S Uher, G AF Kettle, AJ Andreae, MO Amouroux, D Andreae, TW Bates, TS Berresheim, H Bingemer, H Boniforti, R Curran, MAJ DiTullio, GR Helas, G Jones, GB Keller, MD Kiene, RP Leck, C Levasseur, M Malin, G Maspero, M Matrai, P McTaggart, AR Mihalopoulos, N Nguyen, BC Novo, A Putaud, JP Rapsomanikis, S Roberts, G Schebeske, G Sharma, S Simo, R Staubes, R Turner, S Uher, G TI A global database of sea surface dimethylsulfide (DMS) measurements and a procedure to predict sea surface DMS as a function of latitude, longitude, and month SO GLOBAL BIOGEOCHEMICAL CYCLES LA English DT Review ID NORTH-ATLANTIC OCEAN; CHARACTERIZATION EXPERIMENT ACE-1; BIOGENIC SULFUR EMISSIONS; EQUATORIAL PACIFIC-OCEAN; MARINE BOUNDARY-LAYER; SOUTHERN INDIAN-OCEAN; DIMETHYLSULFONIOPROPIONATE DMSP; SEASONAL-VARIATION; CLOUD ALBEDO; BETA-DIMETHYLSULPHONIOPROPIONATE AB A database of 15,617 point measurements of dimethylsulfide (DMS) in surface waters along with lesser amounts of data for aqueous and particulate dimethylsulfoniopropionate concentration, chlorophyll concentration, sea surface salinity and temperature, and wind speed has been assembled. The database was processed to create a series of climatological annual and monthly 1 degrees x1 degrees latitude-longitude squares of data. The results were compared to published fields of geophysical and biological parameters. No significant correlation was found between DMS and these parameters, and no simple algorithm could be found to create monthly fields of sea surface DMS concentration based on these parameters. Instead, an annual map of sea surface DMS was produced using an algorithm similar to that employed by Conkright et al. [1994]. In this approach, a first-guess field of DMS sea surface concentration measurements is created and then a correction to this field is generated based on actual measurements. Monthly sea surface grids of DMS were obtained using a similar scheme, but the sparsity of DMS measurements made the method difficult to implement. A scheme was used which projected actual data into months of the year where no data were otherwise present. C1 Max Planck Inst Chem, Biogeochem Dept, D-55020 Mainz, Germany. Univ Pau & Pays Adour, CNRS, Lab Chim Analyt Bioinorgan & Environm, F-64053 Pau 9, France. NOAA, Pacific Marine Environm Lab, Seattle, WA 98115 USA. MOHp, DWD, D-82383 Hohenpeisenberg, Germany. Univ Frankfurt, D-60325 Frankfurt, Germany. ENEA, Ctr Ric Ambiente Marino, I-19100 La Spezia, Italy. Univ Tasmania, Antarct CRC & Australian Antarct Div, Hobart, Tas 7001, Australia. Univ Charleston, Grice Marine Lab, Charleston, SC 29412 USA. James Cook Univ N Queensland, Townsville, Qld 4811, Australia. Bigelow Lab Ocean Sci, Boothbay Harbor, ME 04575 USA. Univ S Alabama, Dept Marine Sci, Mobile, AL 36688 USA. Univ Stockholm, Dept Meteorol, S-10691 Stockholm, Sweden. Minist Peches & Oceans, Inst Maurice Lamontagne, Mt Joli, PQ G5H 3Z4, Canada. Univ E Anglia, Norwich NR4 7TJ, Norfolk, England. CISE SpA, Milan, Italy. Australian Antarctic Div, Kingston, Tas 7150, Australia. Univ Crete, GR-71409 Iraklion, Greece. CEN Saclay, CNRS, CEA,DSM,LSCE Uniti Mixte Rech, Lab Sci Climat & Environm, F-91191 Gif Sur Yvette, France. Commiss European Communities, Joint Res Ctr, I-21020 Ispra, Italy. Atmospher Environm Serv, Toronto, ON M3H 5T4, Canada. Inst Ciencias Mar, E-08039 Barcelona, Catalonia, Spain. Univ Newcastle Upon Tyne, Newcastle Upon Tyne NE1 7RU, Tyne & Wear, England. RP Kettle, AJ (reprint author), Max Planck Inst Chem, Biogeochem Dept, POB 3060, D-55020 Mainz, Germany. RI Berresheim, Harald/F-9670-2011; Malin, Gill/C-6985-2009; Mihalopoulos, Nikolaos/H-5327-2016; Bates, Timothy/L-6080-2016; Andreae, Meinrat/B-1068-2008; OI Malin, Gill/0000-0002-3639-9215; Mihalopoulos, Nikolaos/0000-0002-1282-0896; Andreae, Meinrat/0000-0003-1968-7925; RAPSOMANIKIS, SPYRIDON/0000-0002-7883-0894; Amouroux, David/0000-0002-0056-8590 NR 161 TC 386 Z9 393 U1 2 U2 64 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0886-6236 J9 GLOBAL BIOGEOCHEM CY JI Glob. Biogeochem. Cycle PD JUN PY 1999 VL 13 IS 2 BP 399 EP 444 DI 10.1029/1999GB900004 PG 46 WC Environmental Sciences; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Geology; Meteorology & Atmospheric Sciences GA 213GQ UT WOS:000081264700009 ER PT J AU Quay, P Stutsman, J Wilbur, D Snover, A Dlugokencky, E Brown, T AF Quay, P Stutsman, J Wilbur, D Snover, A Dlugokencky, E Brown, T TI The isotopic composition of atmospheric methane SO GLOBAL BIOGEOCHEMICAL CYCLES LA English DT Article ID TROPOSPHERIC METHANE; GROWTH-RATE; CARBON; CH4; OXIDATION; OH; C-14; HEMISPHERE; DEPLETION; EMISSIONS AB Measurements of the C-13/C-12, D/H and C-14 composition Of atmospheric methane (CH4) between 1988 and 1995 are presented. The C-13/C-12 measurements represent the first global data set with time series records presented for Point Barrow, Alaska (71 degrees N), Olympic Peninsula, Washington (48 degrees N), Mauna Loa, Hawaii (20 degrees N), American Samoa (14 degrees S), Cape Grim, Australia (41 degrees S), and Baring Head, New Zealand (41 degrees S). North-south trends of the C-13/C-12 and D/H of atmospheric CH4 from air samples collected during oceanographic research cruises in the Pacific Ocean are also presented. The mean annual delta(13)C increased southward from about -47.7 parts per thousand at 71 degrees N to -47.2 parts per thousand at 41 degrees S. The amplitude of the seasonal cycle in delta(13)C ranged from about 0.4 parts per thousand at 71 degrees N to 0.1 parts per thousand at 14 degrees S. The seasonal delta(13)C cycle at sites in tropical latitudes could be explained by CH4 loss via reaction with OH radical, whereas at temperate and polar latitudes in the northern hemisphere seasonal changes in the delta(13)C Of th, CH4 source were needed to explain the seasonal cycle. The higher delta(13)C value in the southern (-47.2 parts per thousand) versus northern (-47.4 parts per thousand) hemisphere was a result of interhemispheric transport of CH4. A slight interannual delta(13)C increase of 0.02+/-0.005 parts per thousand yr(-1) was measured at all sites between 1990 and 1995. The mean delta D of atmospheric CH4 was -86+/-3 parts per thousand between 1989 and 1995 with a 10 parts per thousand depletion in the northern versus southern hemisphere. The C-14 content of CH4 measured at 48 degrees N increased from 122 to 128 percent modern between 1987 and 1995. The proportion of CH4 released from fossil sources was 18+/-9% in the early 1990s as derived from the C-14 content of CH4. C1 Univ Washington, Sch Oceanog, Seattle, WA 98195 USA. Univ Washington, Dept Chem, Seattle, WA 98195 USA. NOAA, Climate Monitoring & Diagnost Lab, Boulder, CO 80303 USA. Univ Calif Lawrence Livermore Natl Lab, Ctr Accelerator Mass Spectrometry, Livermore, CA 94551 USA. RP Quay, P (reprint author), Univ Washington, Sch Oceanog, Box 357940, Seattle, WA 98195 USA. NR 63 TC 187 Z9 192 U1 1 U2 49 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0886-6236 J9 GLOBAL BIOGEOCHEM CY JI Glob. Biogeochem. Cycle PD JUN PY 1999 VL 13 IS 2 BP 445 EP 461 DI 10.1029/1998GB900006 PG 17 WC Environmental Sciences; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Geology; Meteorology & Atmospheric Sciences GA 213GQ UT WOS:000081264700010 ER PT J AU Ciais, P Friedlingstein, P Schimel, DS Tans, PP AF Ciais, P Friedlingstein, P Schimel, DS Tans, PP TI A global calculation of the delta C-13 of soil respired carbon: Implications for the biospheric uptake of anthropogenic CO2 SO GLOBAL BIOGEOCHEMICAL CYCLES LA English DT Article ID ATMOSPHERIC CO2; SIMULATION; WORLDWIDE; TURNOVER; ISOTOPE AB The continuing emissions of fossil CO2 depleted in C-13 have been causing a gradual decrease in atmospheric delta(13)C by roughly 1.4 parts per thousand since preindustrial times. The progressive penetration of this perturbation into the land biota causes the soil organic matter to be enriched in 13C with respect to recently formed plant material. This effect which we call the "biotic isotope disequilibrium" is important when it comes to deducing the terrestrial carbon fluxes by using delta(13)C in atmospheric CO2. We have estimated the geographical distribution of the isotopic disequilibrium, which is primarily influenced by the turnover of carbon in the various ecosystems, from the output of two biospheric models, (SLAVE and CENTURY). The disequilibrium is estimated to shift up the delta(13)C of atmospheric CO2 by the same amount as a net sink of 0.6 Gt C yr(-1) in the land biota. This "fake" terrestrial sink due to the isotopic disequilibrium is distributed mainly in northern midlatitudes (0.2 Gt C yr(-1)) and tropical forests (0.3 Gt C yr(-1)). C1 CEA, Lab Sci Climat & Environm, F-91191 Gif Sur Yvette, France. NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Natl Ctr Atmospher Res, Boulder, CO 80307 USA. NOAA, Climate Monitoring & Diagnost Lab, Boulder, CO 80303 USA. RP Ciais, P (reprint author), CEA, Lab Sci Climat & Environm, F-91191 Gif Sur Yvette, France. RI Friedlingstein, Pierre/H-2700-2014 NR 28 TC 37 Z9 37 U1 1 U2 9 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0886-6236 J9 GLOBAL BIOGEOCHEM CY JI Glob. Biogeochem. Cycle PD JUN PY 1999 VL 13 IS 2 BP 519 EP 530 DI 10.1029/98GB00072 PG 12 WC Environmental Sciences; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Geology; Meteorology & Atmospheric Sciences GA 213GQ UT WOS:000081264700016 ER PT J AU Weinberg, KL Munro, PT AF Weinberg, KL Munro, PT TI The effect of artificial light on escapement beneath a survey trawl SO ICES JOURNAL OF MARINE SCIENCE LA English DT Article; Proceedings Paper CT Theme Session W on the Catching Performance of Fishing Gears Used in Surveys, at the ICES Annual Science Conference CY SEP 26-27, 1997 CL BALTIMORE, MARYLAND SP Int Council Explorat Sea DE artificial illumination; artificial light; bottom trawl; catchability; escapement; fish behaviour; footrope; survey trawl; underwater video ID FISH; GEAR AB An underwater video system is under investigation by the National Marine Fisheries Service for use in studying the capture efficiency of a survey bottom trawl's footrope in diverse habitats commonly sampled during surveys. This system utilizes a 50-watt quartz halogen light since most survey stations are at depths greater than natural light can penetrate for low-light camera use. One potential shortcoming to this approach is that the light emitted might alter fish behaviour and thereby bias estimates of escapement. The light effect on escapement was examined by attaching the video system onto a trawl filled with an auxiliary capture bag to retain those fish which would have otherwise escaped beneath. A paired towing experiment (unlit vs. lit) was conducted to test the hypothesis that there is no effect on capture proportion due to the addition of artificial light. ANOVA was used to test for the effect both fish length and water depth had on escapement. Since neither length nor depth were significant, a paired t test (alpha=0.05) was used to test the null hypothesis. For five of the six species examined, we found no effect of the light on fish escapement. Only flathead sole (Hippoglossoides elassodon) showed a statistically significant difference in capture proportion due to artificial light, the proportion decreasing by 0.0698. (C) 1999 International Council for the Exploration of the Sea. C1 NOAA, Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr, Resource Assessment & Conservat Engn Div, Seattle, WA 98115 USA. RP Weinberg, KL (reprint author), NOAA, Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr, Resource Assessment & Conservat Engn Div, 7600 Sand Point Way NE, Seattle, WA 98115 USA. NR 18 TC 15 Z9 15 U1 0 U2 3 PU ACADEMIC PRESS LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 1054-3139 J9 ICES J MAR SCI JI ICES J. Mar. Sci. PD JUN PY 1999 VL 56 IS 3 BP 266 EP 274 DI 10.1006/jmsc.1999.0442 PG 9 WC Fisheries; Marine & Freshwater Biology; Oceanography SC Fisheries; Marine & Freshwater Biology; Oceanography GA 211ZM UT WOS:000081191800003 ER PT J AU Somerton, D Ianelli, J Walsh, S Smith, S Godo, OR Ramm, D AF Somerton, D Ianelli, J Walsh, S Smith, S Godo, OR Ramm, D TI Incorporating experimentally derived estimates of survey trawl efficiency into the stock assessment process: a discussion SO ICES JOURNAL OF MARINE SCIENCE LA English DT Article; Proceedings Paper CT Theme Session W on the Catching Performance of Fishing Gears Used in Surveys, at the ICES Annual Science Conference CY SEP 26-27, 1997 CL BALTIMORE, MARYLAND SP Int Council Explorat Sea DE trawl efficiency; catchability; stock assessment; catch-at-age models ID CAPTURE EFFICIENCY; THEORETICAL-MODEL; SAMPLING TRAWL; GEAR; FISH; AGE AB The efficiency (Q) of survey trawls can now be estimated using a variety of experimental techniques. In this paper, we review these techniques, then consider how the estimates of Q might best be used in stock assessment. Although catch-at-age models such as tuned VPA and Stock Synthesis can estimate the catchability (q) of a survey trawl when the required time series of catch and survey catch per unit effort (c.p.u.e.) data are sufficiently informative, if the time series are short, q estimates may be quite imprecise. In such cases, q in a catch-at-age model might be fixed at a value derived from an experimental estimate of Q. Furthermore, data series are sometimes so deficient that catch-at-age methods can not be used and fishery managers must turn to swept-area estimates of biomass. In these cases, experimentally estimated values of Q may allow less biased estimates of biomass than those now derived under the assumption of Q=1.0. (C) 1999 International Council for the Exploration of the Sea. C1 Alaska Fisheries Sci Ctr, Natl Marine Fisheries Serv, Seattle, WA 98115 USA. NW Atlantic Fisheries Ctr, Dept Fisheries & Oceans, St Johns, NF, Canada. Bedford Inst Oceanog, Marine Fish Div, Dartmouth, NS, Canada. Inst Marine Res, N-5024 Bergen, Norway. Dept Primary Ind & Fisheries, Div Fisheries, Darwin, NT 0801, Australia. RP Somerton, D (reprint author), Alaska Fisheries Sci Ctr, Natl Marine Fisheries Serv, 7600 Sand Point Way NE, Seattle, WA 98115 USA. OI Godo, Olav Rune/0000-0001-8826-8068 NR 22 TC 33 Z9 33 U1 0 U2 1 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 1999 VL 56 IS 3 BP 299 EP 302 DI 10.1006/jmsc.1999.0443 PG 4 WC Fisheries; Marine & Freshwater Biology; Oceanography SC Fisheries; Marine & Freshwater Biology; Oceanography GA 211ZM UT WOS:000081191800007 ER PT J AU Raviv, D Djaja, EW AF Raviv, D Djaja, EW TI Technique for enhancing the performance of discretized controllers SO IEEE CONTROL SYSTEMS MAGAZINE LA English DT Article C1 Florida Atlantic Univ, Robot Ctr, Boca Raton, FL 33431 USA. Florida Atlantic Univ, Dept Elect Engn, Boca Raton, FL 33431 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Raviv, D (reprint author), Florida Atlantic Univ, Robot Ctr, Boca Raton, FL 33431 USA. NR 10 TC 5 Z9 10 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 0272-1708 J9 IEEE CONTR SYST MAG JI IEEE Control Syst. Mag. PD JUN PY 1999 VL 19 IS 3 BP 52 EP 57 DI 10.1109/37.768540 PG 6 WC Automation & Control Systems SC Automation & Control Systems GA 200FL UT WOS:000080528900006 ER PT J AU Oates, DE Habib, YM Lehner, CJ Vale, LR Ono, RH Dresselhaus, G Dresselhaus, MS AF Oates, DE Habib, YM Lehner, CJ Vale, LR Ono, RH Dresselhaus, G Dresselhaus, MS TI Measurements and modeling of microwave impedance of high-T-c grain boundaries SO IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY LA English DT Article; Proceedings Paper CT 1998 Applied Superconductivity Conference CY SEP 13-18, 1998 CL PALM DESERT, CALIFORNIA ID SURFACE IMPEDANCE; THIN-FILMS; SUPERCONDUCTORS; JUNCTIONS AB We present measurements and modeling of the microwave-frequency (rf) power-dependent impedance of YBCO thin-film grain-boundaries, The measurements were performed using a stripline-resonator technique that separates the characteristics of the grain boundary from the rest of the film. The devices were fabricated on sapphire bicrystal substrates with misorientation angles varying from 2 to 24 degrees and on single crystals, Measurements of the de I-T: characteristics were also performed. The rf measurements are presented as a function of rf current (0.1 mA to 1 A) and temperature (6 to 70 K). Grain-boundary angles of 10 and 24 degrees show Josephson-junction behavior in the rf measurements, but at angles of 5 degrees or less the rf impedance is indistinguishable from films grown on single-crystal substrates in contrast to de measurements that show reduced critical current for the 5 degrees grain boundary. The measured impedance of the large angles is compared with a long-junction model which fits the measured data qualitatively. The measurements and modeling show the creation, annihilation, and motion of Josephson vortices by rf currents which produce the observed nonlinearities In the impedance. We also present measurements of second harmonic generation. C1 MIT, Lincoln Lab, Lexington, MA 02173 USA. MIT, Dept Phys, Cambridge, MA 02139 USA. AFRL, Hanscom AFB, MA USA. NIST, Boulder, CO USA. RP Oates, DE (reprint author), MIT, Lincoln Lab, 244 Wood St, Lexington, MA 02173 USA. NR 15 TC 9 Z9 9 U1 0 U2 3 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 1051-8223 J9 IEEE T APPL SUPERCON JI IEEE Trans. Appl. Supercond. PD JUN PY 1999 VL 9 IS 2 BP 2446 EP 2451 DI 10.1109/77.784970 PN 2 PG 6 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA 225MA UT WOS:000081964300256 ER PT J AU Rudman, DA Stork, FJB Booth, JC Juang, JY Vale, LR Beatty, GJ Williams, CI Beall, JA Ono, RH Qadri, SB Osofsky, MS Skelton, EF Claassen, JH Gibson, G MacManus-Driscoll, JL Malde, N Cohen, LF AF Rudman, DA Stork, FJB Booth, JC Juang, JY Vale, LR Beatty, GJ Williams, CI Beall, JA Ono, RH Qadri, SB Osofsky, MS Skelton, EF Claassen, JH Gibson, G MacManus-Driscoll, JL Malde, N Cohen, LF TI Role of oxygen pressure during deposition on the microwave properties of YBCO films SO IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY LA English DT Article; Proceedings Paper CT 1998 Applied Superconductivity Conference CY SEP 13-18, 1998 CL PALM DESERT, CALIFORNIA ID THIN-FILMS; SUPERCONDUCTING FILMS; SURFACE-RESISTANCE; TEMPERATURE; INHOMOGENEITIES; YBA2CU3O7-DELTA AB We have studied the effect of oxygen pressure (PO,) during pulsed laser deposition on the properties of YBCO films, with particular attention to the low power microwave surface resistance R-s. Above a threshold oxygen pressure the properties of the films are nearly independent of PO2 during deposition and are typical of high quality YBCO films. The films made below this threshold pressure have increased disorder which produces a reduced T-c and an expanded c-axis lattice parameter. However, these films also have significantly reduced low temperature R-s, which is likely a direct result of the increased scattering in these films. Preliminary Raman measurements show no increase in the Y-Ba cation disorder in these low PO2 films, so that a different disorder mechanism must be present. C1 Natl Inst Stand & Technol, Boulder, CO 80309 USA. USN, Res Lab, Washington, DC 20375 USA. Univ London Imperial Coll Sci Technol & Med, Blackett Lab, Ctr Superconduct, London, England. Natl Chiao Tung Univ, Hsinchu, Taiwan. RP Rudman, DA (reprint author), Natl Inst Stand & Technol, 325 Broadway, Boulder, CO 80309 USA. RI Osofsky, Michael/A-1050-2010 NR 17 TC 10 Z9 10 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 1051-8223 J9 IEEE T APPL SUPERCON JI IEEE Trans. Appl. Supercond. PD JUN PY 1999 VL 9 IS 2 BP 2460 EP 2464 DI 10.1109/77.784975 PN 2 PG 5 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA 225MA UT WOS:000081964300259 ER PT J AU Miklich, AH Przybysz, JX Smith, TJ Benz, SP Harvey, TE AF Miklich, AH Przybysz, JX Smith, TJ Benz, SP Harvey, TE TI Superconducting thin-film transformers at microwave frequencies SO IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY LA English DT Article; Proceedings Paper CT 1998 Applied Superconductivity Conference CY SEP 13-18, 1998 CL PALM DESERT, CALIFORNIA ID LINE AB We describe the use of thin-film superconducting transformers at frequencies up to 20 GHz. Transformers with turns ratios of 2, 4, and 7 were fabricated out of Nb and tested in a liquid-He Dewar. The measured S-parameters showed considerably less bandwidth than predicted based on a consideration of the lumped element inductances of the circuit elements, We present an alternative model for the transformer where each part of the patterned circuit is treated as a distributed element (a transmission line). Despite the simplicity of the model, simulations using it agree well with the measured data without using any fitted parameters. These simulations take only a few minutes to compute on a typical workstation, making the model well suited as a design tool. C1 Northrop Grumman Sci & Technol Ctr, Pittsburgh, PA USA. Natl Inst Stand & Technol, Boulder, CO USA. RP Miklich, AH (reprint author), Northrop Grumman Sci & Technol Ctr, Pittsburgh, PA USA. NR 7 TC 2 Z9 3 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 1051-8223 J9 IEEE T APPL SUPERCON JI IEEE Trans. Appl. Supercond. PD JUN PY 1999 VL 9 IS 2 BP 3062 EP 3065 DI 10.1109/77.783675 PN 3 PG 4 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA 225MC UT WOS:000081964500055 ER PT J AU Hilton, GC Wollman, DA Irwin, KD Dulcie, LL Bergren, NF Martinis, JM AF Hilton, GC Wollman, DA Irwin, KD Dulcie, LL Bergren, NF Martinis, JM TI Superconducting transition-edge microcalorimeters for X-ray microanalysis SO IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY LA English DT Article; Proceedings Paper CT 1998 Applied Superconductivity Conference CY SEP 13-18, 1998 CL PALM DESERT, CALIFORNIA ID HIGH-RESOLUTION; DETECTORS AB We have developed high-performance x-ray microcalorimeters based on superconducting transition-edge sensors. These superconducting detectors, which are cooled by a compact adiabatic demagnetization refrigerator mounted on a scanning electron microscope, provide significant new capabilities for x-ray microanalysis. The performance characteristics of these detectors are nearly ideal for many applications in x-ray microanalysis, attaining an energy resolution of 3-4 eV at a counting rate of 500 s(-1) and an effective collection area of 4 mm(2). The excellent energy resolution enables measurements of chemical shifts in x-ray spectra caused by changes in electron binding energy due to chemical bonding. Another important application of these detectors is analysis of contaminant particles and defects for the semiconductor industry. We present data demonstrating the analysis of particles on Si wafers, including 0.3 mu m tungsten particles and 0.1 mu m alumina particles. C1 Natl Inst Stand & Technol, Boulder, CO 80303 USA. RP Hilton, GC (reprint author), Natl Inst Stand & Technol, 325 Broadway, Boulder, CO 80303 USA. NR 14 TC 6 Z9 6 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 1051-8223 J9 IEEE T APPL SUPERCON JI IEEE Trans. Appl. Supercond. PD JUN PY 1999 VL 9 IS 2 BP 3177 EP 3181 DI 10.1109/77.783704 PN 3 PG 5 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA 225MC UT WOS:000081964500084 ER PT J AU Ruggiero, ST Mischke, MP Tanner, CE Wilson, AJ Vale, LR Rudman, DA AF Ruggiero, ST Mischke, MP Tanner, CE Wilson, AJ Vale, LR Rudman, DA TI Wavelength dependent photoresponse in YBCO thin-film systems SO IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY LA English DT Article; Proceedings Paper CT 1998 Applied Superconductivity Conference CY SEP 13-18, 1998 CL PALM DESERT, CALIFORNIA ID PHOTOINDUCED SUPERCONDUCTIVITY; BOLOMETRIC RESPONSE; PHOTOCONDUCTIVITY; STATE AB We present results on the structures photoresponse of YBCO narrow-line structures with deliberately broadened resistive transitions. We have explored the photoresponse of these systems as a function of temperature, bias current and power at wavelengths of 0.670, 0.850 and 10.6 mu m and at frequencies from 3 to 10(5) Hz at 0.670 mu m. The response was bolometric in nature in the vicinity of T-c (R similar to 30V/W). However, the response below T-c shows significant enhancement at 0.670 mu m, The wavelength regime of the enhancement suggests the participation of transient photodoping of the material or related phenomena. C1 Univ Notre Dame, Notre Dame, IN 46556 USA. Univ Wisconsin, Platteville, WI 53818 USA. Natl Inst Stand & Technol, Boulder, CO 80303 USA. RP Ruggiero, ST (reprint author), Univ Notre Dame, Notre Dame, IN 46556 USA. NR 17 TC 1 Z9 1 U1 1 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 1051-8223 J9 IEEE T APPL SUPERCON JI IEEE Trans. Appl. Supercond. PD JUN PY 1999 VL 9 IS 2 BP 3182 EP 3185 DI 10.1109/77.783705 PN 3 PG 4 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA 225MC UT WOS:000081964500085 ER PT J AU Benz, SP Burroughs, CJ Harvey, TE Hamilton, CA AF Benz, SP Burroughs, CJ Harvey, TE Hamilton, CA TI Operating conditions for a pulse-quantized AC and DC bipolar voltage source SO IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY LA English DT Article; Proceedings Paper CT 1998 Applied Superconductivity Conference CY SEP 13-18, 1998 CL PALM DESERT, CALIFORNIA ID JOSEPHSON-JUNCTIONS; PHASE-LOCK; CONVERTER; STABILITY; STANDARD AB We have developed an accurate sc and de bipolar voltage source based on the quantized pulses of Josephson junctions. A factor-of-6 increase in output voltage over previous unipolar waveforms is achieved by generating bipolar waveforms where arrays of junctions are biased with both a broadband two-level digital code and a sine wave We use simulations to determine the optimum operating conditions as a function of frequency and as a function of the phase difference between the digital code and the sinusoidal drive. C1 Natl Inst Stand & Technol, Boulder, CO 80303 USA. RP Benz, SP (reprint author), Natl Inst Stand & Technol, 325 Broadway, Boulder, CO 80303 USA. NR 12 TC 25 Z9 25 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 1051-8223 J9 IEEE T APPL SUPERCON JI IEEE Trans. Appl. Supercond. PD JUN PY 1999 VL 9 IS 2 BP 3306 EP 3309 DI 10.1109/77.783736 PN 3 PG 4 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA 225MC UT WOS:000081964500116 ER PT J AU Vale, LR Ono, RH Talvacchio, J Forrester, MG Hunt, BD Dilorio, MS Yang, KY Yoshizumi, S AF Vale, LR Ono, RH Talvacchio, J Forrester, MG Hunt, BD Dilorio, MS Yang, KY Yoshizumi, S TI Long term stability of YBCO-based Josephson junctions SO IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY LA English DT Article; Proceedings Paper CT 1998 Applied Superconductivity Conference CY SEP 13-18, 1998 CL PALM DESERT, CALIFORNIA ID YBA2CU3O7-DELTA AB We report on a study of long term aging in three different types of YBa2Cu3O7-x Josephson junctions. Junction aging will affect the choices made in integrating this technology with actual applications. The junction types used in this study are (a) Go-doped barrier edge SNS junctions, (b) noble-metal SNS step-edge junctions, and (c) bicrystal junctions which are either unpassivated or passivated in situ with a normal metal shunt or an epitaxial insulator. While all the junctions show degradation, for some the long term survival rate is encouraging. C1 Natl Inst Stand & Technol, Boulder, CO 80303 USA. Northrop Grumman STC, Pittsburgh, PA 15235 USA. Magnesensors Inc, San Diego, CA 92121 USA. RP Vale, LR (reprint author), Natl Inst Stand & Technol, 325 Broadway, Boulder, CO 80303 USA. NR 9 TC 2 Z9 3 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 1051-8223 J9 IEEE T APPL SUPERCON JI IEEE Trans. Appl. Supercond. PD JUN PY 1999 VL 9 IS 2 BP 3382 EP 3385 DI 10.1109/77.783755 PN 3 PG 4 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA 225MC UT WOS:000081964500135 ER PT J AU Li, HQ Ono, RH Vale, LR Rudman, DA Liou, SH AF Li, HQ Ono, RH Vale, LR Rudman, DA Liou, SH TI Interactions between bicrystal Josephson junctions in a multilayer structure SO IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY LA English DT Article; Proceedings Paper CT 1998 Applied Superconductivity Conference CY SEP 13-18, 1998 CL PALM DESERT, CALIFORNIA ID SUPERCONDUCTING WEAK LINKS; PHASE-LOCKING AB We have fabricated and studied a variety of devices based on stacked YBa2Cu3Ox bicrystal Josephson junctions in a multilayer structure. The proximity of the junctions in the two layers produces a large number of effects based on interactions between the junctions. Voltage locking and current locking were observed in the stacked junctions. The voltage locking is due to the ac path provided by a SrTiO3 layer between the stacked junctions. The current locking is likely the result of a Josephson vortex interaction. C1 Natl Inst Stand & Technol, Boulder, CO 80303 USA. Univ Nebraska, Lincoln, NE 68588 USA. RP Li, HQ (reprint author), Natl Inst Stand & Technol, 325 Broadway, Boulder, CO 80303 USA. NR 12 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 1051-8223 J9 IEEE T APPL SUPERCON JI IEEE Trans. Appl. Supercond. PD JUN PY 1999 VL 9 IS 2 BP 3417 EP 3420 DI 10.1109/77.783763 PN 3 PG 4 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA 225MC UT WOS:000081964500143 ER PT J AU Robbes, D Cheenne, N Hamet, JF Rice, JP AF Robbes, D Cheenne, N Hamet, JF Rice, JP TI Thermal boundary resistance of a YBa2Cu3O7-delta/SrTiO3 multilayer strip SO IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY LA English DT Article; Proceedings Paper CT 1998 Applied Superconductivity Conference CY SEP 13-18, 1998 CL PALM DESERT, CALIFORNIA ID SILICON AB The present work deals with measurements of the thermal resistance at the boundary between a YBa2Cu3O7-delta (YBCO) thin film and its substrate. Above the film's critical temperature (T-c) the YBCO strips were heated by Joule effect. We used a method based on the third harmonic generation of the voltage across the strips. At high frequency of the heating current, the deduced thermal resistance is dominated by the boundary effect. We used that method to evaluate the possible enhancement of the thermal insulation between the upper layer (YBCO thicker film) and the il MgO substrate when ten 2 x 8 mn thick YBCO / STO bi-layers are deposited between them. The strips were 600 mu m long and 40 mu m wide. The thermal resistance was measured at various frequencies and temperatures above T-c, both for a single layer taken as a reference sample and for a multilayer sample. Below T-c, we used an optical heating of the strips to evaluate the insulation effect obtained with multilayered sample. The ratio of thermal conductances was close to 11, thus demonstrating the insulation enhancement obtained with the multilayered structure. The effect could lead to antenna-coupled micro-bolometers with improved performances. C1 Inst Sci Mat & Rayonnement, GREYC, F-14050 Caen, France. Inst Sci Mat & Rayonnement, CRISMAT, F-14050 Caen, France. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Robbes, D (reprint author), Inst Sci Mat & Rayonnement, GREYC, 6 Blvd Marechal Juin, F-14050 Caen, France. NR 7 TC 6 Z9 6 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 1051-8223 J9 IEEE T APPL SUPERCON JI IEEE Trans. Appl. Supercond. PD JUN PY 1999 VL 9 IS 2 BP 3874 EP 3877 DI 10.1109/77.783873 PN 3 PG 4 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA 225MC UT WOS:000081964500253 ER PT J AU Xu, YZ Ekin, JW Clickner, CC AF Xu, YZ Ekin, JW Clickner, CC TI Low-frequency noise of YBCO/Au junctions SO IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY LA English DT Article; Proceedings Paper CT 1998 Applied Superconductivity Conference CY SEP 13-18, 1998 CL PALM DESERT, CALIFORNIA ID INTERFACE; CONTACT AB We have fabricated es-situ c-asis YBCO/Au junctions with lo tv contact resistivities. These de rices exhibit large low-frequency resistance fluctuations. At room temperature the junction noise spectrum is 1/f like. At liquid nitrogen temperature (77 K) and lower, the noise spectrum depends sensitively on the bias current, with certain bias levels producing clear two-level fluctuation behavior. The normalized resistance noise for these junctions at temperatures below 77 K has an average value of 2 to 3x10(-5) (Hz)(-1/2) We discuss practical issues related to junction noise properties. C1 Natl Inst Stand & Technol, Boulder, CO 80303 USA. RP Xu, YZ (reprint author), Natl Inst Stand & Technol, 325 Broadway, Boulder, CO 80303 USA. NR 7 TC 0 Z9 0 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 1051-8223 J9 IEEE T APPL SUPERCON JI IEEE Trans. Appl. Supercond. PD JUN PY 1999 VL 9 IS 2 BP 3990 EP 3993 DI 10.1109/77.783902 PN 3 PG 4 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA 225MC UT WOS:000081964500282 ER PT J AU Burroughs, CJ Benz, SP Harvey, TE Hamilton, CA AF Burroughs, CJ Benz, SP Harvey, TE Hamilton, CA TI 1 volt DC programmable Josephson voltage standard SO IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY LA English DT Article; Proceedings Paper CT 1998 Applied Superconductivity Conference CY SEP 13-18, 1998 CL PALM DESERT, CALIFORNIA AB NIST has developed a programmable Josephson voltage standard (JVS) that produces intrinsically stable voltages that are programmable from -1.1 V to +1.1 V. The rapid settling time (1 mu s), large operating current margins (2 to 4 mA), and inherent step stability of this new system make it superior to a conventional JVS for many de measurements. This improved performance is made possible by a new integrated-circuit technology using intrinsically shunted superconductor-normal-superconductor (SNS) Josephson junctions. These junctions operate at lower excitation frequencies (10 to 20 GHz) than a conventional JVS and have 100 times greater noise immunity. The Josephson chip consists of a binary array sequence of 32 768 SNS Josephson junctions. The chip has been integrated into a completely automated system that is finding application in mechanical / electrical watt-balance experiments, evaluation of thermal voltage converters, electron-counting capacitance standards, and metrology triangle experiments. C1 Natl Inst Stand & Technol, Boulder, CO 80303 USA. RP Burroughs, CJ (reprint author), Natl Inst Stand & Technol, 325 Broadway, Boulder, CO 80303 USA. NR 9 TC 53 Z9 53 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 1051-8223 J9 IEEE T APPL SUPERCON JI IEEE Trans. Appl. Supercond. PD JUN PY 1999 VL 9 IS 2 BP 4145 EP 4149 DI 10.1109/77.783938 PN 3 PG 5 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA 225MC UT WOS:000081964500318 ER PT J AU Booth, JC Beall, JA Rudman, DA Vale, LR Ono, RH Holloway, CL Qadri, SB Osofsky, MS Skelton, EF Claassen, JH Gibson, G MacManus-Driscoll, JL Malde, N Cohen, LF AF Booth, JC Beall, JA Rudman, DA Vale, LR Ono, RH Holloway, CL Qadri, SB Osofsky, MS Skelton, EF Claassen, JH Gibson, G MacManus-Driscoll, JL Malde, N Cohen, LF TI Simultaneous optimization of the linear and nonlinear microwave response of YBCO films and devices SO IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY LA English DT Article; Proceedings Paper CT 1998 Applied Superconductivity Conference CY SEP 13-18, 1998 CL PALM DESERT, CALIFORNIA ID HIGH-TEMPERATURE SUPERCONDUCTORS; THIN-FILMS; YBA2CU3O7-DELTA AB We present results of a systematic study of the effect of film deposition temperature on both the linear and nonlinear response of superconducting YBa2Cu3O7-delta (YBCO) thin films and devices at microwave frequencies. Measurements of the unpatterned films show that samples grown by pulsed laser deposition at a lower substrate temperature (740 degrees C) display a smaller low-temperature residual surface resistance compared to films grown at a higher substrate temperature (780 degrees C). However, the same films which display low residual surface resistance also show increased nonlinear effects (measured by third harmonic generation) at all temperatures. Analysis of these results suggests that the increased defects present in the films grown at the lower deposition temperature are responsible for both the lower surface resistance and the higher third harmonic generation observed in these samples. We discuss the consequences of these results for the simultaneous optimization of both linear and nonlinear microwave properties of HTS thin films and devices. C1 Natl Inst Stand & Technol, Boulder, CO 80303 USA. NTIA, Inst Telecommun Sci, Boulder, CO 80303 USA. USN, Res Lab, Washington, DC 20375 USA. Univ London Imperial Coll Sci Technol & Med, Blackett Lab, Ctr Superconduct, London, England. RP Booth, JC (reprint author), Natl Inst Stand & Technol, 325 Broadway, Boulder, CO 80303 USA. RI Osofsky, Michael/A-1050-2010 NR 16 TC 23 Z9 23 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 1051-8223 J9 IEEE T APPL SUPERCON JI IEEE Trans. Appl. Supercond. PD JUN PY 1999 VL 9 IS 2 BP 4176 EP 4180 DI 10.1109/77.783945 PN 3 PG 5 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA 225MC UT WOS:000081964500325 ER PT J AU Kenyon, M Cobb, JL Amar, A Song, D Zimmerman, NM Lobb, CJ Wellstood, FC AF Kenyon, M Cobb, JL Amar, A Song, D Zimmerman, NM Lobb, CJ Wellstood, FC TI Behavior of a charged two-level fluctuator in an Al-AlOx-Al single-electron transistor in the normal and superconducting state SO IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY LA English DT Article; Proceedings Paper CT 1998 Applied Superconductivity Conference CY SEP 13-18, 1998 CL PALM DESERT, CALIFORNIA ID COULOMB-BLOCKADE ELECTROMETER; JUNCTIONS AB We have studied the behavior of a charged two-level fluctuator in an Al-AlOx-Al single-electron transistor (SET) in the normal state over a temperature range from 85 mK to 3 K. The fluctuator caused the SET's island charge to shift by Delta Q(o) = 0.1 +/- 0.025 e with an escape rate out of each state which was periodic in the gate voltage. We compare our results to a model which assumes the fluctuator resides in one of the tunnel junctions and discuss model predictions for when the device is in the superconducting state. C1 Univ Maryland, Dept Phys, Ctr Superconduct Res, College Pk, MD 20742 USA. NIST, Gaithersburg, MD 20899 USA. RP Kenyon, M (reprint author), Univ Maryland, Dept Phys, Ctr Superconduct Res, College Pk, MD 20742 USA. RI Joint Quantum Institute, NIST/UMD/H-4494-2011 NR 13 TC 6 Z9 7 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 1051-8223 J9 IEEE T APPL SUPERCON JI IEEE Trans. Appl. Supercond. PD JUN PY 1999 VL 9 IS 2 BP 4261 EP 4264 DI 10.1109/77.783966 PN 3 PG 4 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA 225MC UT WOS:000081964500346 ER PT J AU McDonald, DG Phelan, RJ Vale, LR Ono, RH Rudman, DA AF McDonald, DG Phelan, RJ Vale, LR Ono, RH Rudman, DA TI Passivation, transition width, and noise for YBCO bolometers on silicon SO IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY LA English DT Article; Proceedings Paper CT 1998 Applied Superconductivity Conference CY SEP 13-18, 1998 CL PALM DESERT, CALIFORNIA ID YBACUO SUPERCONDUCTING FILMS; THIN-FILMS; ELECTROTHERMAL FEEDBACK; WATER; DEGRADATION; STABILITY; YBA2CU3O7; SILVER AB We are developing YBa2Cu3O7-x (YBCO) thermometers for large area bolometers that include a heater for calibration by the electrical substitution of power. Because YBCO on buffered Si is under mechanical stress and must be very thin to avoid cracking, we find it is electrically sensitive to its passivation layer. For example, passivation by SrTiO3 raised the noise in our films by about a factor of 100. An alternative is to first cap the YBCO with Au for passivation, and then add an insulator for electrical isolation. Such devices have a narrower transition width, by a factor of 3.9. A model with a shunt resistor across the superconductor predicts a narrowing of the transition, but by less than the observed amount, The noise equivalent temperatures of our thermometers, about 4 nK Hz(-1/2), are not degraded by the normal metal shunt, although the resistance is decreased. The resistance can be raised using AgAu alloy in place of Au, with equivalent noise performance. AgAu alloy in place of Au, with equivalent noise performance. C1 Boulder Metr Inc, Boulder, CO USA. NIST, Boulder, CO USA. RP McDonald, DG (reprint author), Boulder Metr Inc, Boulder, CO USA. NR 19 TC 7 Z9 7 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 1051-8223 J9 IEEE T APPL SUPERCON JI IEEE Trans. Appl. Supercond. PD JUN PY 1999 VL 9 IS 2 BP 4471 EP 4474 DI 10.1109/77.784018 PN 3 PG 4 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA 225MC UT WOS:000081964500398 ER PT J AU Blackburn, DL Courtois, B AF Blackburn, DL Courtois, B TI Thermal investigations of ICs and microstructures (THERMINIC) - Foreword SO IEEE TRANSACTIONS ON COMPONENTS AND PACKAGING TECHNOLOGIES LA English DT Editorial Material C1 NIST, Gaithersburg, MD 20899 USA. TIMA Lab, F-38031 Grenoble, France. RP Blackburn, DL (reprint author), NIST, Gaithersburg, MD 20899 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 1521-3331 J9 IEEE T COMPON PACK T JI IEEE Trans. Compon. Packaging Technol. PD JUN PY 1999 VL 22 IS 2 BP 229 EP 230 DI 10.1109/TCAPT.1999.774736 PG 2 WC Engineering, Manufacturing; Engineering, Electrical & Electronic; Materials Science, Multidisciplinary SC Engineering; Materials Science GA 217VV UT WOS:000081520400014 ER PT J AU Dziuba, RF Kile, LL AF Dziuba, RF Kile, LL TI An automated guarded bridge system for the comparison of 10 k Omega standard resistors SO IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT LA English DT Article DE automatic testing; bridge circuits; calibration; resistance; resistance measurement; resistors; standards AB An automated guarded resistance bridge has been specifically developed at the National Institute of Standards and Technology (NIST) for the calibration of high-quality 10 k Ohm standard resistors. The system is designed to compare up to 30 nominally equal, four-terminal resistors with a resolution and combined relative standard uncertainty of 0.01 x 10(-6) and 0.02 x 10(-6), respectively. It features a self-balancing detector circuit, and a programmable coaxial connector switch for selecting resistors. With a few minor modifications, the system is capable of comparing other nominally equal resistors in the range 100 Ohm to 1 M Ohm. C1 Technol Adm, Natl Inst Stand & Technol, Div Elect, Elect & Elect Engn Lab,US Dept Commerce, Gaithersburg, MD 20899 USA. RP Dziuba, RF (reprint author), Technol Adm, Natl Inst Stand & Technol, Div Elect, Elect & Elect Engn Lab,US Dept Commerce, Gaithersburg, MD 20899 USA. NR 5 TC 4 Z9 4 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 0018-9456 J9 IEEE T INSTRUM MEAS JI IEEE Trans. Instrum. Meas. PD JUN PY 1999 VL 48 IS 3 BP 673 EP 677 DI 10.1109/19.772194 PG 5 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA 213XT UT WOS:000081299100001 ER PT J AU Krupka, J Derzakowski, K Abramowicz, A Tobar, ME Geyer, RG AF Krupka, J Derzakowski, K Abramowicz, A Tobar, ME Geyer, RG TI Use of whispering-gallery modes for complex permittivity determinations of ultra-low-loss dielectric materials SO IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES LA English DT Article DE anisotropy; complex permittivity; dielectric resonator; low-loss dielectric materials; sapphire; temperature coefficient; whispering-gallery modes ID RESONANT MODES; FREQUENCIES; CRYSTALS AB Whispering-gallery modes are used for very accurate permittivity, dielectric loss, and temperature coefficient of permittivity measurements for both isotropic and uniaxially anisotropic dielectric materials. The relationship between resonant frequencies, dimensions of the resonant structure, and permittivity of the sample under test is calculated with a radial mode-matching technique. The relative accuracy of these computations is better then 10(-4). The influence of conductor losses' on dielectric loss tangent determination is treated for both whispering-gallery-mode and TE01 delta-mode dielectric-resonator techniques. Two permittivity tensor components of sapphire and their temperature dependence were measured from 4.2 to 300 K, The total uncertainty in permittivity when use is made of whispering-gallery modes was estimated to be less than 0.05%, The uncertainty was limited principally by uncertainty in sample dimensions, Experimental and calculated resonant frequencies of several whispering-gallery modes differed by no more than 0.01%. The dielectric loss tangent of sapphire parallel and perpendicular to its anisotropy axis was calculated to be less than 10(-9) at 4.2 K, The permittivity and dielectric loss tangent of a commercially available low-loss high-permittivity ceramic material has also been measured at S- and C-band frequencies using a large number of whispering-gallery modes. C1 Warsaw Univ Technol, Inst Radioelect, PL-00662 Warsaw, Poland. Warsaw Univ Technol, Inst Elect Fundamentals, PL-00665 Warsaw, Poland. Univ Western Australia, Dept Phys, Nedlands, WA 6009, Australia. Natl Inst Stand & Technol, RF Technol Div, Boulder, CO 80303 USA. RP Krupka, J (reprint author), Warsaw Univ Technol, Inst Radioelect, PL-00662 Warsaw, Poland. RI Tobar, Michael/C-9763-2009 OI Tobar, Michael/0000-0002-3139-1994 NR 22 TC 139 Z9 139 U1 2 U2 18 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 JUN PY 1999 VL 47 IS 6 BP 752 EP 759 DI 10.1109/22.769347 PN 1 PG 8 WC Engineering, Electrical & Electronic SC Engineering GA 207YA UT WOS:000080962300016 ER PT J AU Booth, JC Holloway, CL AF Booth, JC Holloway, CL TI Conductor loss in superconducting planar structures: Calculations and measurements SO IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES LA English DT Article DE attenuation; coplanar transmission lines; high-temperature superconductors; microstrip; superconducting microwave devices ID MICROSTRIP; LINES; FILMS AB We present closed-form expressions of the attenuation constant due to conductor loss far superconducting coplanar waveguide and microstrip transmission lines. These expressions, valid for arbitrary conductor thickness, make use of a numerically determined quantity (the stopping distance Delta) that depends on the material properties and edge Shape of the superconducting transmission line. Once Delta is determined; the attenuation constant for any planar geometry can be obtained without further numerical calculation, making, this technique attractive for use in the design of circuits incorporating superconducting planar elements. The results of this calculation compare favorably with full numerical calculations and also with experimental data on high-temperature superconducting coplanar transmission lines, illustrating the accuracy and applicability of the calculation for determining the conductor loss of superconducting circuit elements. C1 Natl Inst Stand & Technol, Boulder, CO 80303 USA. NTIA, Inst Telecommun Sci, Boulder, CO 80303 USA. RP Booth, JC (reprint author), Natl Inst Stand & Technol, 325 Broadway, Boulder, CO 80303 USA. NR 15 TC 17 Z9 17 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 0018-9480 J9 IEEE T MICROW THEORY JI IEEE Trans. Microw. Theory Tech. PD JUN PY 1999 VL 47 IS 6 BP 769 EP 774 DI 10.1109/22.769349 PN 1 PG 6 WC Engineering, Electrical & Electronic SC Engineering GA 207YA UT WOS:000080962300018 ER PT J AU Hagwood, C Clough, R Fields, R AF Hagwood, C Clough, R Fields, R TI Estimation of the stress-threshold for the Weibull inverse power law SO IEEE TRANSACTIONS ON RELIABILITY LA English DT Article DE threshold stress; inverse power-law; maximum likelihood; modified maximum likelihood; Weibull distribution AB Lifetime data on stress rupture of copper joints made with certain lead-free solders suggest that specimens under 'stress below a certain threshold' run indefinitely, without failure. A commonly used model for this type of data is the Weibull inverse power law that includes a threshold. If the threshold is unknown, this estimation problem presents several difficulties for statistical treatment. The largest problem is: as the threshold approaches the minimum of the data (stresses) the likelihood approaches infinity, thus there is no global maximum. A modified maximum likelihood approach, in the spirit of Cohen is used to resolve this problem. The method is similar to Cohen's, but interesting differences occur for censored data. The results show that modifications of the Cohen method produce estimates of the parameters in the Weibull inverse power threshold law. C1 Natl Inst Stand & Technol, Stat Engn Div, Gaithersburg, MD 20899 USA. Natl Inst Stand & Technol, Div Met, Gaithersburg, MD 20899 USA. RP Hagwood, C (reprint author), Natl Inst Stand & Technol, Stat Engn Div, 100 Bur Dr,Stop 8980, Gaithersburg, MD 20899 USA. NR 8 TC 4 Z9 4 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 0018-9529 J9 IEEE T RELIAB JI IEEE Trans. Reliab. PD JUN PY 1999 VL 48 IS 2 BP 176 EP 181 DI 10.1109/24.784277 PG 6 WC Computer Science, Hardware & Architecture; Computer Science, Software Engineering; Engineering, Electrical & Electronic SC Computer Science; Engineering GA 227XT UT WOS:000082105800011 ER PT J AU Gilles, MK Burkholder, JB Ravishankara, AR AF Gilles, MK Burkholder, JB Ravishankara, AR TI Rate coefficients for the reaction of OH with Cl-2, Br-2, and I-2 from 235 to 354 K SO INTERNATIONAL JOURNAL OF CHEMICAL KINETICS LA English DT Article ID PRODUCT MEASUREMENTS; RATE-CONSTANT; 298 K; KINETICS; HOI; CLO; IO; MECHANISM; BRCL AB Rate coefficients for the reaction of OH with Cl-2, (k(1)), Br-2, (k(2)) and I-2, (k(3)), were measured under pseudo-first-order conditions in OH. OH was produced by pulsed laser photolysis of H2O2 (or HNO3) and its temporal profile was monitored by laser-induced fluorescence. The measured rate coefficients for k(1) (231-354 K) and k(2) (235-357 K) are: k(1) (T) = (3.77 +/- 1.02) X 10(-12) exp[-(1228 +/- 140)/T] cm(3) molecule(-1) s(-1) k(2) (T) = (1.98 +/- 0.51) X 10(-11) exp[(238 +/- 70)/T] cm(3) molecule(-1) s(-1) k(3) was independent of temperature between 240 and 348 K with an average Value of (2.10 +/- 0.60) X 10(-10) cm(3) molecule(-1) s(-1). The quoted uncertainties are 2 sigma (95% confidence limits, 1 sigma(A) = A sigma(lnA)) and include estimated systematic errors. Our measurements significantly improve the accuracy of k(1). This is the first report of a slight negative temperature dependence for k(2) and of the temperature independence of k(3). (C) 1999 John Wiley & Sons, Inc.* C1 Univ Colorado, Cooperat Inst Res Environm Studies, Boulder, CO 80309 USA. Univ Colorado, Dept Chem & Biochem, Boulder, CO 80309 USA. NOAA, ERL, Aeron Lab, Boulder, CO 80303 USA. RP Gilles, MK (reprint author), NOAA, ERL, Aeron Lab, R-E-AL2,325 Broadway, Boulder, CO 80303 USA. RI Burkholder, James/H-4914-2013; Ravishankara, Akkihebbal/A-2914-2011 NR 21 TC 26 Z9 26 U1 0 U2 2 PU JOHN WILEY & SONS INC PI NEW YORK PA 605 THIRD AVE, NEW YORK, NY 10158-0012 USA SN 0538-8066 J9 INT J CHEM KINET JI Int. J. Chem. Kinet. PD JUN PY 1999 VL 31 IS 6 BP 417 EP 424 DI 10.1002/(SICI)1097-4601(1999)31:6<417::AID-KIN3>3.0.CO;2-A PG 8 WC Chemistry, Physical SC Chemistry GA 199MA UT WOS:000080484800003 ER PT J AU May, PT Keenan, TD Zrnic, DS Carey, LD Rutledge, SA AF May, PT Keenan, TD Zrnic, DS Carey, LD Rutledge, SA TI Polarimetric radar measurements of tropical rain at a 5-cm wavelength SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID DUAL-POLARIZED RADAR; DIFFERENTIAL PHASE; PRECIPITATION; REFLECTIVITY; ATTENUATION; GAUGES AB A 5-cm wavelength (C band) polarimetric radar was deployed during the MCTEX (Maritime Continent Thunderstorm Experiment) field program. This paper investigates the use of the: C-band data for quantitative rainfall measurements with particular emphasis on specific differential phase (K-DP) and traditional reflectivitybased rain-rate estimates in moderate to high rain rates (10-200 mm h(-1)). Large values of backscatter differential phase shift are occasionally seen in these data, thus resonance scattering effects; are important. A consensus algorithm for K-DP estimation in these cases is described. The rain-rate estimates are compared with the data from a d-scale rain gauge network. The K-DP estimates are shown to produce the highest quality data, although variations in drop size distribution characteristics have a significant effect on the rain estimates. When corrections are applied for beam blockage and attenuation, good agreement can also be obtained with ZR-based estimates. The attenuation corrections were made using a polarimetric variable; total differential phase, which provides an estimate of the total water content along the path. The polarimetric estimates of total accumulation also shaw excellent agreement. C1 Bur Meteorol Res Ctr, Melbourne, Vic 3001, Australia. NOAA, Environm Res Labs, Natl Severe Storms Lab, Norman, OK 73069 USA. Colorado State Univ, Dept Atmospher Sci, Ft Collins, CO 80523 USA. RP May, PT (reprint author), Bur Meteorol Res Ctr, GPO Box 1289K, Melbourne, Vic 3001, Australia. NR 43 TC 48 Z9 52 U1 0 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 JUN PY 1999 VL 38 IS 6 BP 750 EP 765 DI 10.1175/1520-0450(1999)038<0750:PRMOTR>2.0.CO;2 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 208TB UT WOS:000081006800008 ER PT J AU Matrosov, SY Kropfli, RA Reinking, RF Martner, BE AF Matrosov, SY Kropfli, RA Reinking, RF Martner, BE TI Prospects for measuring rainfall using propagation differential phase in X- and K-a-radar bands SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID SIZE DISTRIBUTIONS; SHIFT; CLOUD; SHAPE AB Model calculations and measurements of the specific propagation and backscatter differential phase shifts. (K-DP and delta(o), respectively) in rain are discussed for X- (lambda similar to 3 cm) and K-a-band (lambda similar to 0.8 cm) radar wavelengths. The details of the drop size distribution have only a small effect on the relationships between K-DP and rainfall rate R. These relationships, however, are subject to significant variations due to the assumed model of the drop aspect ratio as a function of their size. The backscatter differential phase Shift at X hand for-rain rates of less than about 15 mm h(-1) is generally small and should not pose a serious problem when estimating K-DP from the total phase difference at range intervals of several kilometers. The main advantage of using X-band wavelengths compared to S-band (lambda similar to 10-11 cm) wavelengths is an increase in K-DP by a factor of about 3 for the same rainfall rate. The relative contribution of the backscatter differential phase to the total phase difference at K-a band is significantly larger than at X band. This makes propagation and backscatter phase Shift: contributions comparable for most practical cases and poses difficulties in estimating rainfall rate from K-a-band measurements of the differential phase. Experimental studies of rain using X-band differential phase measurements were conducted near Boulder, Colorado, in a stratiform, intermittent rain with a rate averaging about 4-5 mm h(-1). The differential phase shift approach proved to be effective for such modest rains, and finer spatial resolutions were possible in comparison to those achieved with similar measurements at longer wavelengths. A K-DP-R relation derived for the mean drop aspect ratio (R = 20.5K(DP)(0.80)) provided a satisfactory,agreement between rain accumulations derived from radar measurements of the differential phase and data from several nea;by high-resolution surface rain gauges. For two rainfall events, radar estimates based on the assumed mean drop aspect ratio were, on average, quite close to the gauge measurements with about 38% relative standard deviation of radar data from the gauge data. C1 Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80303 USA. NOAA, Environm Technol Lab, Boulder, CO USA. RP Matrosov, SY (reprint author), Univ Colorado, Cooperat Inst Res Environm Sci, 325 Broadway,R-E-ET6, Boulder, CO 80303 USA. NR 31 TC 37 Z9 40 U1 0 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 JUN PY 1999 VL 38 IS 6 BP 766 EP 776 DI 10.1175/1520-0450(1999)038<0766:PFMRUP>2.0.CO;2 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 208TB UT WOS:000081006800009 ER PT J AU Gallo, KP Owen, TW AF Gallo, KP Owen, TW TI Satellite-based adjustments for the urban heat island temperature bias SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID SURFACE TEMPERATURES; REGIONAL CLIMATE; UNITED-STATES; CITY LIGHTS; AVHRR DATA; DATA SET; VEGETATION; AREAS AB Monthly and seasonal relationships between urban-rural differences in minimum, maximum, and average temperatures measured at surface based observation stations were compared to satellite-derived Advanced Very High Resolution Radiometer estimates of a normalized difference vegetation index (NDVI) and surface radiant temperature (T-sfc).The relationships between surface- and satellite-derived. variables were developed during 1989-91 and tested on data acquired during 1992-93. The urban-rural differences in;air temperature were linearly related to urban-rural differences in the NDVI and T-sfc. A statistically significant but relatively small (less than 40%) amount of the variation in these urban-rural differences in air temperature [the urban heat island (UHI) bias] was associated with variation in the urban-rural differences in NDVI and T-sfc. A comparison of the satellite-based estimates of the UHI bias with population-based estimates. of the UHI bias indicated similar levels of error. The use of satellite-derived data may contribute to a globally consistent method for analysis of the urban heat island bias. C1 Natl Climat Ctr, Asheville, NC 28801 USA. NOAA, Off Res & Applicat, NESDIS, Washington, DC USA. RP Natl Climat Ctr, 151 Patton Ave, Asheville, NC 28801 USA. EM Kevin.P.Gallo@noaa.gov RI Gallo, Kevin P./F-5588-2010 NR 27 TC 97 Z9 108 U1 3 U2 20 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 1999 VL 38 IS 6 BP 806 EP 813 DI 10.1175/1520-0450(1999)038<0806:SBAFTU>2.0.CO;2 PG 8 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 208TB UT WOS:000081006800013 ER PT J AU Silva, TJ Lee, CS Crawford, TM Rogers, CT AF Silva, TJ Lee, CS Crawford, TM Rogers, CT TI Inductive measurement of ultrafast magnetization dynamics in thin-film Permalloy SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID RESONANCE AB An inductive technique for the measurement of dynamical magnetic processes in thin-film materials is described. The technique is demonstrated using 50 nm films of Permalloy (Ni81Fe19). Data are presented for impulse- and step-response experiments with the applied field pulse oriented in the plane of the film and transverse to the anisotropy axis. Rotation times as short as 200 ps and free oscillations of the magnetization after excitation are clearly observed. The oscillation frequency increases as the dc bias field parallel to the anisotropy axis increases as predicted by classical gyromagnetic theory. The data are fitted to the Landau-Lifshitz equation, and damping parameters are determined as a function of dc bias field. Damping for both impulse and step excitations exhibits a strong dependence on bias field. Damping for step excitations is characterized by an anomalous transient damping which rapidly increases at low dc bias field. Transformation of the data to the frequency domain reveals a higher order precessional mode which is also preferentially excited at low dc bias fields. A possible source for both phenomena is precessional mode saturation for large peak rotations. The technique has the potential for 20 ps resolution, although only 120 ps resolution is demonstrated due to the limited bandwidth of the waveguides used. (C) 1999 American Institute of Physics. [S0021-8979(99)06111-3]. C1 Natl Inst Stand & Technol, Boulder, CO 80303 USA. Univ Colorado, Dept Phys, Boulder, CO 80309 USA. RP Silva, TJ (reprint author), Natl Inst Stand & Technol, 325 Broadway, Boulder, CO 80303 USA. RI Silva, Thomas/C-7605-2013 OI Silva, Thomas/0000-0001-8164-9642 NR 24 TC 258 Z9 259 U1 4 U2 38 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD JUN 1 PY 1999 VL 85 IS 11 BP 7849 EP 7862 DI 10.1063/1.370596 PG 14 WC Physics, Applied SC Physics GA 197FL UT WOS:000080354300051 ER PT J AU Stowe, LL Davis, PA McClain, EP AF Stowe, LL Davis, PA McClain, EP TI Scientific basis and initial evaluation of the CLAVR-1 global clear cloud classification algorithm for the advanced very high resolution radiometer SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article ID CLIMATOLOGY-PROJECT ISCCP; AVHRR DATA; SCANNER DATA; SATELLITE; NIMBUS-7; AEROSOL; RADIANCES; SHORTWAVE; FIELDS; NOAA-7 AB An algorithm for the remote sensing of global cloud cover using multispectral radiance measurements from the Advanced Very High Resolution Radiometer (AVHRR) on board National Oceanic and Atmospheric Administration (NOAA) polar-orbiting satellites has been developed. The CLAVR-1 (Clouds from AVHRR-Phase I) algorithm classifies 2 x 2 pixel arrays from the Global Area Coverage (GAC) 4-km-resolution archived database into CLEAR, MIXED, and CLOUDY categories. The algorithm uses a sequence of multispectral contrast, spectral, and spatial signature threshold tests to perform the classification. The various tests and the derivation of their thresholds are presented. CLAVR-1 has evolved through experience in applying it to realtime NOAA-11 data, and retrospectively through the NOAA AVHRR Pathfinder Atmosphere project, where 16 years of data have been reprocessed into cloud, radiation budget, and aerosol climatologies. The classifications are evaluated regionally with image analysis, and it is concluded that the algorithm does well at classifying perfectly clear pixel arrays, except at high latitudes in their winter seasons. It also has difficulties with classifications over some desert and mountainous regions and when viewing regions of ocean specular reflection. Generally, the CLAVR-1 fractional cloud amounts, when computed using a statistically equivalent spatial coherence method, agree to within about 0.05-0.10 of image/analyst estimates on average. There is a tendency for CLAVR-1 to underestimate cloud amount when it is large and to overestimate it when small. C1 NOAA, Natl Environm Satellite Data & Informat Serv, Off Res & Applicat, Washington, DC 20233 USA. RP Stowe, LL (reprint author), NOAA, Natl Environm Satellite Data & Informat Serv, Off Res & Applicat, Washington, DC 20233 USA. NR 50 TC 171 Z9 178 U1 3 U2 9 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 1999 VL 16 IS 6 BP 656 EP 681 DI 10.1175/1520-0426(1999)016<0656:SBAIEO>2.0.CO;2 PG 26 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA 205BZ UT WOS:000080802600003 ER PT J AU Wilfong, TL Merritt, DA Lataitis, RJ Weber, BL Wuertz, DE Strauch, RG AF Wilfong, TL Merritt, DA Lataitis, RJ Weber, BL Wuertz, DE Strauch, RG TI Optimal generation of radar wind profiler spectra SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article ID CLUTTER; SYSTEM AB Radar wind profilers (RWPs) sense the mean and turbulent motion of the clear air through Doppler shifts induced along several (3-5) upward-looking beams. RWP signals, like all radars signals, are often contaminated. The contamination is clearly evident in the associated Doppler spectra, and automatic routines designed to extract meteorological quantities from these spectra often yield inaccurate results. Much of the observed contamination is due to an aliasing of higher frequency signals into the clear-air portion of the spectrum and a broadening of the spectral contaminants caused by the relatively short: time series used to generate Doppler spectra. In the past, this source of contamination could not be avoided because of limitations on the size and speed of RWP processing computers. Today's computers, however, are able to process larger amounts of data at greatly increased speeds. Here it is shown how standard and well-known spectral processing methods can be applied to significantly longer time series to reduce contamination in the radar spectra and thereby improve the accuracy and the reliability of meteorological products derived from RWP systems. In particular, spectral processing methods to identify and remove contamination that is often aliased into the clear-air portion of the spectrum are considered. Optimal techniques for combining multiple spectra to produce averaged spectra are also discussed. C1 NOAA, ERL, Boulder, CO 80303 USA. Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. RP Wilfong, TL (reprint author), NOAA, ERL, ET4,325 Broadway, Boulder, CO 80303 USA. NR 22 TC 10 Z9 10 U1 0 U2 3 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0739-0572 J9 J ATMOS OCEAN TECH JI J. Atmos. Ocean. Technol. PD JUN PY 1999 VL 16 IS 6 BP 723 EP 733 DI 10.1175/1520-0426(1999)016<0723:OGORWP>2.0.CO;2 PG 11 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA 205BZ UT WOS:000080802600007 ER PT J AU Lugez, CL Thompson, WE Jacox, ME Snis, A Panas, I AF Lugez, CL Thompson, WE Jacox, ME Snis, A Panas, I TI Infrared spectra of (NO)(2)(+), (NO)(2)(-), and (NO)(3)(-) trapped in solid neon SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID VIBRATIONAL-SPECTRA; MATRIX-ISOLATION; IONS; NO; ATOMS; N2O; STABILIZATION; TRANSITION; ANIONS; ARGON AB New studies of the infrared spectra of the products which result on codeposition at approximately 5 K of a Ne: NO sample with Ne atoms that have been excited in a microwave discharge have led to new and revised assignments for several ionic species. The appearance of the nu(1) absorption of ONNO+ for several new species with asymmetric isotopic substitution, but for no symmetrically substituted species, confirms the trans ground-state configuration for ONNO+. The behavior of a neon-matrix product absorption at 1227.5 cm(-1) parallels that of an argon-matrix absorption at 1221.0 cm(-1) which has recently been assigned to trans-ONNO-. The identity of the carrier of a product absorption at 1424.1 cm(-1), contributed by a vibration of two symmetrically equivalent NO groups, has not been definitively established. This absorption exhibits complex photodestruction behavior. Three absorptions are assigned to cis, cis-(NO)(3)(-), which has C-2v symmetry, with the aid of density functional calculations of the isotopic substitution pattern for the vibrational fundamentals of this species. Similar calculations of the isotopic substitution patterns for other structures result in poor agreement with the experiments. Photodestruction of cis, cis-(NO)(3)(-) trapped in solid neon yields the N2O ... NO2- complex. (C) 1999 American Institute of Physics. [S0021-9606(99)01021-1]. C1 Natl Inst Stand & Technol, Opt Technol Div, Gaithersburg, MD 20899 USA. Chalmers Univ Technol, Dept Environm Inorgan Chem, S-41296 Gothenburg, Sweden. RP Lugez, CL (reprint author), Natl Inst Stand & Technol, Opt Technol Div, Gaithersburg, MD 20899 USA. OI Panas, Itai/0000-0002-6679-075X NR 34 TC 30 Z9 30 U1 1 U2 2 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD JUN 1 PY 1999 VL 110 IS 21 BP 10345 EP 10358 DI 10.1063/1.478967 PG 14 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 197MT UT WOS:000080369100014 ER PT J AU Kim, SC Chen, J AF Kim, SC Chen, J TI Bottom stress of wind-driven currents over an inner shelf determined from depth-integrated storm surge model SO JOURNAL OF COASTAL RESEARCH LA English DT Article DE bottom stress; wind-driven current; inner shelf; coastal circulation; storm surges AB Bottom stress from wind-driven current was explicitly calculated using the SLOSH (Sea, Lake, and Overland Surges from Hurricanes) model in which the bottom stress is riot collinear with the direction of depth-averaged flow. The asymptotic behavior of wind-flow relationships in a shallow ocean with a horizontally infinite: extent shows that the SLOSH model estimates reasonably the magnitude and the direction of the bottom stress over a range of the shallow water condition. For the broad and shallow inner shelf of the Middle Atlantic Eight (MAB), the SLOSH model for steady flow for a semi-infinite ocean resulted in reasonable estimation of bottom flow under the high wind conditions of typical extratropical origin. C1 Coll William & Mary, Sch Marine Sci, Gloucester Point, VA 23062 USA. NOAA, Natl Weather Serv, Tech Dev Lab, Silver Spring, MD 20910 USA. RP Kim, SC (reprint author), Coll William & Mary, Sch Marine Sci, Gloucester Point, VA 23062 USA. NR 18 TC 2 Z9 2 U1 0 U2 0 PU COASTAL EDUCATION & RESEARCH FOUNDATION PI LAWRENCE PA 810 EAST 10TH STREET, LAWRENCE, KS 66044 USA SN 0749-0208 J9 J COASTAL RES JI J. Coast. Res. PD SUM PY 1999 VL 15 IS 3 BP 766 EP 773 PG 8 WC Environmental Sciences; Geography, Physical; Geosciences, Multidisciplinary SC Environmental Sciences & Ecology; Physical Geography; Geology GA 215CU UT WOS:000081365000015 ER PT J AU Carlisle, JA Blankenship, SR Smith, RN Shirley, EL Terminello, LJ Jia, JJ Callcott, TA Ederer, DL AF Carlisle, JA Blankenship, SR Smith, RN Shirley, EL Terminello, LJ Jia, JJ Callcott, TA Ederer, DL TI Soft-X-ray fluorescence studies of solids SO JOURNAL OF ELECTRON SPECTROSCOPY AND RELATED PHENOMENA LA English DT Article; Proceedings Paper CT 12th International Conference on Vacuum Ultraviolet Radiation Physics (VUV-12) CY AUG 03-07, 1998 CL SAN FRANCISCO, CA DE X-ray emission spectra; resonant X-ray scattering; band structure; excitons; graphite ID RESONANT INELASTIC-SCATTERING; BAND-STRUCTURE; GRAPHITE; ABSORPTION; EMISSION; EXCITONS; EDGE AB Resonant inelastic X-ray scattering (RIXS) has been observed in many systems above and below their core threshold. Below threshold, inelastic-loss features are observed, which disperse linearly with excitation energy, but as the excitation increases above the core binding energy, nonlinear dispersive effects are observed. These two effects are described by the same physics of coherent fluorescence. Very good agreement between experiment and simulated RIXS is achieved using a simple one-electron framework. However, significant questions have arisen concerning core-hole effects and their influence on RIXS. In this work, the role core-excitons play in the RIXS process is examined in finer detail in graphite, by using narrow-band excitation, and through comparison between experiment and simulated spectra which include the core-hole effects explicitly in the modeling. Based on these findings, we conclude that core-hole effects play a minor but detectable role in the RIXS observed from graphite. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Virginia Commonwealth Univ, Richmond, VA 23284 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Univ Calif Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. Univ Tennessee, Knoxville, TN 37996 USA. Tulane Univ, New Orleans, LA 70118 USA. RP Carlisle, JA (reprint author), Virginia Commonwealth Univ, Richmond, VA 23284 USA. EM jacarlis@vcu.edu NR 20 TC 3 Z9 3 U1 2 U2 2 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 JUN PY 1999 VL 101 SI SI BP 839 EP 845 DI 10.1016/S0368-2048(98)00434-4 PG 7 WC Spectroscopy SC Spectroscopy GA 210JT UT WOS:000081102000149 ER PT J AU Drexler, ES Berger, JR AF Drexler, ES Berger, JR TI Mechanical deformation in conductive adhesives as measured with electron-beam moire SO JOURNAL OF ELECTRONIC PACKAGING LA English DT Article ID RELIABILITY AB Two forms (paste and film) of isotropically conductive adhesives (CAs) were mechanically loaded in shear mode. The specimens were instrumented with crossed-line gratings so that normal and shear displacements could be measured. The CA paste specimen failed outside the observed region at a stress 28 percent below the manufacturer's predicted value. In the observed region there were no normal strains, only shear strains restricted to the CA. In the film specimen the conducting particles began breaking away from the matrix epoxy at very low loads. However, the specimen continued carrying the additional loading increments until the load was transferred to the adjacent material. C1 Natl Inst Stand & Technol, Div Mat Reliabil, Div 853, Boulder, CO 80303 USA. Colorado Sch Mines, Div Engn, Golden, CO 80401 USA. RP Drexler, ES (reprint author), Natl Inst Stand & Technol, Div Mat Reliabil, Div 853, 325 Broadway, Boulder, CO 80303 USA. RI Berger, John/F-5169-2010 NR 18 TC 6 Z9 6 U1 0 U2 1 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1043-7398 J9 J ELECTRON PACKAGING JI J. Electron. Packag. PD JUN PY 1999 VL 121 IS 2 BP 69 EP 74 DI 10.1115/1.2792670 PG 6 WC Engineering, Electrical & Electronic; Engineering, Mechanical SC Engineering GA 206YX UT WOS:000080909200002 ER PT J AU Kendall, MS Wolcott, TG AF Kendall, MS Wolcott, TG TI The influence of male mating history on male-male competition and female choice in mating associations in the blue crab, Callinectes sapidus (Rathbun) SO JOURNAL OF EXPERIMENTAL MARINE BIOLOGY AND ECOLOGY LA English DT Article DE Callinectes; female choice; male-male competition; mating history ID SEXUAL SELECTION; DUNGENESS CRABS; SUCCESS; EXPERIENCE AB Male Callinectes sapidus allowed complete recovery of sperm resources and then mated a single time had significantly lower vas deferens weight than males allowed complete recovery of sperm resources but prevented from mating. In laboratory experiments, when a recently mated male (having low sperm volume) competed with a male that had not recently mated (having high sperm volume) for a single pubertal female, the female was just as likely to initiate pairing with the recently mated male as with a male that had not recently mated, despite possible reduction in her fertilization potential. At the end of trials in which stable pair formation occurred, recently mated males were paired significantly more often than males that had not recently mated. The combined effects of the lack of mate choice by females and high mating frequency of some males may result in many females in the population receiving low quantities of sperm. (C) 1999 Elsevier Science B.V. All rights reserved. C1 NOAA, NOS, Strateg Environm Assessments Div, Silver Spring, MD 20910 USA. N Carolina State Univ, Dept Marine Earth & Atmospher Sci, Raleigh, NC 27695 USA. RP Kendall, MS (reprint author), NOAA, NOS, Strateg Environm Assessments Div, 1305 EW Highway SSMC-4, Silver Spring, MD 20910 USA. NR 22 TC 40 Z9 44 U1 0 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0022-0981 J9 J EXP MAR BIOL ECOL JI J. Exp. Mar. Biol. Ecol. PD JUN 1 PY 1999 VL 239 IS 1 BP 23 EP 32 DI 10.1016/S0022-0981(99)00022-2 PG 10 WC Ecology; Marine & Freshwater Biology SC Environmental Sciences & Ecology; Marine & Freshwater Biology GA 200XQ UT WOS:000080565800002 ER PT J AU Norton, EC MacFarlane, RB AF Norton, EC MacFarlane, RB TI Lipid class composition of the viviparous yellowtail rockfish over a reproductive cycle SO JOURNAL OF FISH BIOLOGY LA English DT Article DE lipid; lipid class composition; reproductive cycle; viviparous; Sebastes flavidus ID FATTY-ACID COMPOSITION; HERRING CLUPEA-HARENGUS; PIKE ESOX-LUCIUS; COD GADUS-MORHUA; SEBASTES-FLAVIDUS; SEASONAL-CHANGES; MALLOTUS-VILLOSUS; SEXUAL-MATURATION; ATLANTIC SALMON; ENERGY CONTENT AB Triacylglycerols (TAG) were the dominant lipids in liver tissue of both sexes of the viviparous yellowtail rockfish Sebastes flavidus during the spring and summer when greatest feeding occurred. Significant declines in liver TAG during the winter corresponded to increased concentrations of polar lipids (PL), the main component of cell membranes. Elevated PL in female livers relative to those of males preceded the period of ovarian enlargement and may be attributed to the production of vitellogenin. During late vitellogenesis and gestation, ovaries contained significantly elevated concentrations of FL, TAG, and cholesterol. Since yellowtail rockfish are highly fecund and viviparous, large quantities of ovarian PL are required for proliferation of the cell membranes in developing larval tissues. TAG accumulated in ovaries in lower concentrations than PL and were likely metabolized as the main source of energy during gestation. This pattern of ovarian PL concentrations exceeding those of TAG and the presence of oil globules, may be unique to highly fecund, viviparous teleosts and signify an alternative profile to those previously documented for oviparous species. Testes at maximum I-G were only 7% of maximum ovarian size, composed of mainly PL, and lacked a defined lipid dynamic pattern across the reproductive cycle. (C) 1999 The Fisheries Society of the British Isles. C1 Natl Marine Fisheries Serv, SW Fisheries Sci Ctr, Tiburon Lab, Tiburon, CA 94920 USA. RP Norton, EC (reprint author), Natl Marine Fisheries Serv, SW Fisheries Sci Ctr, Tiburon Lab, 3150 Paradise Dr, Tiburon, CA 94920 USA. NR 40 TC 7 Z9 9 U1 0 U2 2 PU ACADEMIC PRESS LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 0022-1112 J9 J FISH BIOL JI J. Fish Biol. PD JUN PY 1999 VL 54 IS 6 BP 1287 EP 1299 DI 10.1006/jfbi.1999.0957 PG 13 WC Fisheries; Marine & Freshwater Biology SC Fisheries; Marine & Freshwater Biology GA 199XG UT WOS:000080508900011 ER PT J AU Smith, DA Milbert, DG AF Smith, DA Milbert, DG TI The GEOID96 high-resolution geoid height model for the United States SO JOURNAL OF GEODESY LA English DT Article DE geoid; GPS; datums; reference systems; gravity ID COEFFICIENT MODELS; GRAVITY; GEODESY AB The 2 arc-minute x 2 are-minute geoid model (GEOID96) for the United States supports the conversion between North American Datum 1983 (NAD 83) ellipsoid heights and North American Vertical Datum 1988 (NAVD 88) Helmert heights. GEOID96 includes information from global positioning system (GPS) height measurements at optically leveled benchmarks. A separate geocentric gravimetric geoid, G96SSS, was first calculated, then datum transformations and least-squares collocation were used to convert from G96SSS to GEOID96. Fits of 2951 GPS/level (ITRF94/NAVD 88) benchmarks to G96SSS show a 15.1-cm root mean square (RMS) around a tilted plane (0.06 ppm, 178 degrees azimuth), with a mean value of -31.4 cm (15.6-cm RMS without plane). This mean represents a bias in NAVD 88 from global mean sea level, remaining nearly constant when computed from subsets of benchmarks. Fits of 2951 GPS/level (NAD 83/NAVD 88) benchmarks to GEOID96 show a 5.5-cm RMS (no tilts, zero average), due primarily to GPS error. The correlated error was 2.5 cm, decorrelating at 40 km, and is due to gravity, geoid and GPS errors. Differences between GEOID96 and GEOID93 range from -122 to + 374 cm due primarily to the non-geocentricity of NAD 83. C1 NOAA, Natl Geodet Survey, Silver Spring, MD 20910 USA. RP NOAA, Natl Geodet Survey, 1315 EW Highway, Silver Spring, MD 20910 USA. EM dru@ngs.noaa.gov NR 46 TC 39 Z9 41 U1 0 U2 1 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0949-7714 EI 1432-1394 J9 J GEODESY JI J. Geodesy PD JUN PY 1999 VL 73 IS 5 BP 219 EP 236 DI 10.1007/s001900050239 PG 18 WC Geochemistry & Geophysics; Remote Sensing SC Geochemistry & Geophysics; Remote Sensing GA 212TA UT WOS:000081231300001 ER PT J AU Lu, G Tsyganenko, NA Lui, ATY Singer, HJ Nagai, T Kokubun, S AF Lu, G Tsyganenko, NA Lui, ATY Singer, HJ Nagai, T Kokubun, S TI Modeling of time-evolving magnetic fields during substorms SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID TAIL CURRENT SHEET; GROWTH-PHASE; CURRENT DISRUPTION; PLASMA SHEET; SYNCHRONOUS ALTITUDE; CURRENT WEDGE; MAGNETOTAIL; MAGNETOSPHERE; SIGNATURES; EXPANSION AB An attempt has been made to model the dynamics of the magnetospheric magnetic field during substorms by modifying the 1996 version of the data-based model by Tsyganenko [1996]. The modified model incorporates an adjustment to the intensity and thickness of the near-tail current sheet and a contribution from the substorm current wedge. These improvements make it possible to use the model to represent the evolution of the magnetic field during the entire substorm sequence of growth, expansion, and recovery. The modeled magnetic fields have been compared to satellite observations during three isolated substorms. According to the model results, during the substorm growth phase the thickness of the tail current sheet was gradually decreased while the intensity of the tail current was gradually increased; by the end of the growth phase a thin current sheet of 190-1340 km in half thickness was formed in a narrow region around X similar to -7.5 R-E, with a maximum westward current density of 9-23 nA/m(2). During the substorm expansion phase an eastward current associated with the substorm current wedge started to develop around X similar to -12 R-E, resulting in a collapse of the previously stretched field configuration. At the peak of an intense substorm the net tail current flow became eastward between X = -11 and X = -13 R-E, accompanied by a negative (southward) B-z tailward of -13 R-E. C1 Natl Ctr Atmospher Res, Altitude Observ, Boulder, CO 80301 USA. Nagoya Univ, Solar Terr Environm Lab, Nagoya, Aichi 46401, Japan. Johns Hopkins Univ, Appl Phys Lab, Laurel, MD 20723 USA. Tokyo Inst Technol, Tokyo 1528551, Japan. NOAA, Space Environm Ctr, Boulder, CO 80303 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Natl Ctr Atmospher Res, Altitude Observ, 3540 Mitchell Lane, Boulder, CO 80301 USA. EM ganglu@ucar.edu RI Lu, Gang/A-6669-2011; Tsyganenko, Nikolai/J-7377-2012 OI Tsyganenko, Nikolai/0000-0002-5938-1579 NR 39 TC 18 Z9 20 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9380 EI 2169-9402 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD JUN 1 PY 1999 VL 104 IS A6 BP 12327 EP 12337 DI 10.1029/1999JA900145 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 201MY UT WOS:000080600400008 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 Solar Terr Phys A, Boulder, CO 80303 USA. RP Coffey, HE (reprint author), NOAA, World Data Ctr Solar Terr Phys A, 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 JUN 1 PY 1999 VL 104 IS A6 BP 12487 EP 12489 DI 10.1029/1999JA900189 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 201MY UT WOS:000080600400021 ER PT J AU Rose, AH Etzel, SM Rochford, KB AF Rose, AH Etzel, SM Rochford, KB TI Optical fiber current sensors in high electric field environments SO JOURNAL OF LIGHTWAVE TECHNOLOGY LA English DT Article DE electric field effects; electrooptic Kerr effect; gas insulated systems; optical fiber current sensor; polarimetric; Sagnac ID GAS-INSULATED SWITCHGEAR; SINGLE-MODE FIBER; SAGNAC INTERFEROMETER; HIGH-VOLTAGE; TEMPERATURE-DEPENDENCE; INDUCED BIREFRINGENCE; VERDET CONSTANT; COMPENSATION; GLASSES AB This paper analyzes the response of optical fiber current sensors that are subjected to high electric fields, such as fields encountered in gas-insulated systems. This paper shows that through the electrooptic (EO) Kerr effect, these fields can cause harmonic distortion of the measured ac current waveform. This harmonic distortion was confirmed experimentally. Also, this paper shows that it is possible to simultaneously measure both current and voltage waveforms and the phase between them using this effect. To minimize the electrooptic Kerr effect, optical fiber current sensors must be screened from high-electric fields. C1 Natl Inst Stand & Technol, Div Optoelect, Boulder, CO 80303 USA. RP Rose, AH (reprint author), Natl Inst Stand & Technol, Div Optoelect, 325 Broadway, Boulder, CO 80303 USA. NR 40 TC 20 Z9 22 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 0733-8724 J9 J LIGHTWAVE TECHNOL JI J. Lightwave Technol. PD JUN PY 1999 VL 17 IS 6 BP 1042 EP 1048 DI 10.1109/50.769306 PG 7 WC Engineering, Electrical & Electronic; Optics; Telecommunications SC Engineering; Optics; Telecommunications GA 203WW UT WOS:000080732000009 ER PT J AU Russek, SE Oti, JO Kim, YK AF Russek, SE Oti, JO Kim, YK TI Switching characteristics of spin valve devices designed for MRAM applications SO JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS LA English DT Article; Proceedings Paper CT 3rd International Symposium on Metallic Multilayers (MML98) held Jointly with the EMRS Symposium on Magnetic Ultrathin Films and Ultrathin Film Nanostructures CY JUN 14-19, 1998 CL VANCOUVER, CANADA DE MRAM; spin-valve; switching AB The low-frequency performance of spin valve giant magnetoresistive devices, designed for digital applications, has been examined as a function of device line width and aspect ratio. NiFe-Co-Cu-Co-NiFe-FeMn devices have been fabricated with line widths down to 0.4 mu m and aspect ratios that varied between 10:1 and 1.5:1. As the del ice line width decreases, the switching fields and switching field asymmetry increase due to magnetostatic effects. As the aspect ratio decreases, the switching field asymmetry increases rapidly and the devices become prone to domain noise. The experimentally observed switching behavior is compared to uniform rotation models to determine the accuracy with which the switching fields can be predicted. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Natl Inst Stand & Technol, Boulder, CO 80303 USA. Samsung Electromech Co, MR Head Div, Seoul, South Korea. RP Russek, SE (reprint author), Natl Inst Stand & Technol, 325 Broadway,MC 814-05, Boulder, CO 80303 USA. EM russek@boulder.nist.gov NR 6 TC 8 Z9 8 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0304-8853 J9 J MAGN MAGN MATER JI J. Magn. Magn. Mater. PD JUN PY 1999 VL 198-99 BP 6 EP 8 DI 10.1016/S0304-8853(98)00590-3 PG 3 WC Materials Science, Multidisciplinary; Physics, Condensed Matter SC Materials Science; Physics GA 204TE UT WOS:000080779600003 ER PT J AU Shima, M Salamanca-Riba, L Moffat, TP McMichael, RD AF Shima, M Salamanca-Riba, L Moffat, TP McMichael, RD TI Structural and magnetic properties of electrodeposited Co Cu multilayers SO JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS LA English DT Article; Proceedings Paper CT 3rd International Symposium on Metallic Multilayers (MML98) held Jointly with the EMRS Symposium on Magnetic Ultrathin Films and Ultrathin Film Nanostructures CY JUN 14-19, 1998 CL VANCOUVER, CANADA DE metallic multilayer; electrodeposition giant magnetoresistance; magnetocrystalline anisotropy; superparamagnetism ID CO/CU MULTILAYERS; COBALT FILMS; GROWTH; ADSORPTION; CU(001); CU(100) AB A series of [Co(x ML)/Cu(17 ML)](100) multilayers were electrodeposited on Si(0 0 1) substrates covered with Cu seed layers. Magnetic hysteresis loops for films with x < 2 ML have sigmoidal shaper and the temperature dependence indicates a superparamagnetic behavior of the ultrathin Co layers. This behavior appears to be due to a discontinuity of the Co layers in the multilayer structure. In contrast, films with x > 2 ML have rectangular loops. In-plane four-fold symmetry is observed for x > 4 ML, which reflects the magnetocrystalline anisotropy of the multilayers. The giant magnetoresistance effect is observed for x > 2 ML. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Univ Maryland, Dept Mat & Nucl Engn, College Pk, MD 20742 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Salamanca-Riba, L (reprint author), Univ Maryland, Dept Mat & Nucl Engn, College Pk, MD 20742 USA. EM riba@eng.umd.edu RI McMichael, Robert/J-8688-2012; Salamanca-Riba, Lourdes/B-3785-2009; OI Salamanca-Riba, Lourdes/0000-0001-8155-6403; McMichael, Robert/0000-0002-1372-664X NR 11 TC 20 Z9 20 U1 1 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0304-8853 J9 J MAGN MAGN MATER JI J. Magn. Magn. Mater. PD JUN PY 1999 VL 198-99 BP 52 EP 54 DI 10.1016/S0304-8853(98)00616-7 PG 3 WC Materials Science, Multidisciplinary; Physics, Condensed Matter SC Materials Science; Physics GA 204TE UT WOS:000080779600018 ER PT J AU Unguris, J Celotta, RJ Tulchinsky, DA Pierce, DT AF Unguris, J Celotta, RJ Tulchinsky, DA Pierce, DT TI Exchange coupling in magnetic multilayers grown on iron whiskers SO JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS LA English DT Article; Proceedings Paper CT 3rd International Symposium on Metallic Multilayers (MML98) held Jointly with the EMRS Symposium on Magnetic Ultrathin Films and Ultrathin Film Nanostructures CY JUN 14-19, 1998 CL VANCOUVER, CANADA DE interlayer exchange coupling; magnetic multilayers; SEMPA; magnetic microstructure; spin density waves ID SPIN-DENSITY-WAVE; FE/CR(001) SUPERLATTICES; CR; FE; INTERFACE; FE/CR/FE(100); LAYERS; PERIOD; FILMS AB Meaningful tests of theoretical predictions of magnetic multilayer properties require the fabrication of multilayers with nearly the same atomic scale precision as the theoretical models. Multilayers grown epitaxially on single-crystal Fe whisker substrates come very close to this ideal standard. We have investigated the growth, magnetic structure, and exchange coupling of Fe/(Ag, Au, Cr, Mn, V, Cu, or Al)/Fe (1 1 0) whisker structures primarily using reflection high-energy electron diffraction (RHEED) and scanning electron microscopy with polarization analysis (SEMPA), and in some systems, confocal magneto-optic Kerr effect (MOKE) microscopy. In eases of nearly layer-by-layer growth, the measured oscillatory coupling periods and strengths agree well with theoretical predictions. For rougher growth, less predictable non-collinear coupling is generally observed. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Natl Inst Stand & Technol, Electron Phys Grp, Gaithersburg, MD 20899 USA. RP Unguris, J (reprint author), Natl Inst Stand & Technol, Electron Phys Grp, Bldg 220,Room B206, Gaithersburg, MD 20899 USA. EM unguris@epg.nist.gov RI Unguris, John/J-3989-2014 NR 26 TC 15 Z9 15 U1 1 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0304-8853 J9 J MAGN MAGN MATER JI J. Magn. Magn. Mater. PD JUN PY 1999 VL 198-99 BP 396 EP 401 DI 10.1016/S0304-8853(98)01139-1 PG 6 WC Materials Science, Multidisciplinary; Physics, Condensed Matter SC Materials Science; Physics GA 204TE UT WOS:000080779600126 ER PT J AU Arnold, CS Dunlavy, M Venus, D Pappas, DP AF Arnold, CS Dunlavy, M Venus, D Pappas, DP TI Magnetic susceptibility determination of the relaxation time for domain-wall motion in perpendicularly magnetized, ultrathin films SO JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS LA English DT Article; Proceedings Paper CT 3rd International Symposium on Metallic Multilayers (MML98) held Jointly with the EMRS Symposium on Magnetic Ultrathin Films and Ultrathin Film Nanostructures CY JUN 14-19, 1998 CL VANCOUVER, CANADA DE ultrathin films; polar Kerr effect; domain-wall motion ID ML NI/W(110) FILMS; TO-NOISE RATIO; TEMPERATURE; TRANSITION; FCC AB The temperature dependence of the magnetic relaxation time tau(T) is investigated in perpendicularly magnetized, ultrathin Fe/2 monolayer Ni/W(1 1 0) films by magnetic susceptibility measurements. Complex magnetic susceptibilities chi(T) = chi(T) + i chi "(T) were measured by the polar Kerr effect as a function of temperature T. In all cases, chi'(T) and chi "( T) have broad peaks that are not obviously related to the Curie temperature T(c). An experimental relaxation time tau(T) is determined from the ratio chi "(T)/chi'(T). The results support previous arguments that the susceptibility arises from domain-wall motion. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Natl Inst Stand & Technol, Boulder, CO 80303 USA. McMaster Univ, Dept Phys, Hamilton, ON L8S 4M1, Canada. McMaster Univ, Brockhouse Inst Mat Res, Hamilton, ON L8S 4M1, Canada. RP Arnold, CS (reprint author), Natl Inst Stand & Technol, 325 Broadway, Boulder, CO 80303 USA. EM stephen.arnold@boulder.nist.gov NR 15 TC 1 Z9 2 U1 1 U2 2 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0304-8853 J9 J MAGN MAGN MATER JI J. Magn. Magn. Mater. PD JUN PY 1999 VL 198-99 BP 465 EP 467 DI 10.1016/S0304-8853(98)01157-3 PG 3 WC Materials Science, Multidisciplinary; Physics, Condensed Matter SC Materials Science; Physics GA 204TE UT WOS:000080779600147 ER PT J AU Nikitenko, VI Gornakov, VS Dedukh, LM Khapikov, AF Moffat, TP Shapiro, AJ Shull, RD Shima, M Salamanca-Riba, L AF Nikitenko, VI Gornakov, VS Dedukh, LM Khapikov, AF Moffat, TP Shapiro, AJ Shull, RD Shima, M Salamanca-Riba, L TI Direct experimental study of the microscopic remagnetization mechanism in Co Cu magnetic superlattices SO JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS LA English DT Article; Proceedings Paper CT 3rd International Symposium on Metallic Multilayers (MML98) held Jointly with the EMRS Symposium on Magnetic Ultrathin Films and Ultrathin Film Nanostructures CY JUN 14-19, 1998 CL VANCOUVER, CANADA DE metallic multilayers; giant magnetoresistance; magnetization reversal; domian structure ID MULTILAYERS AB Using the magneto-optical indicator film technique, the correlation between the magnitude of the giant magnetoresistance (GMR) and the micromechanism of the magnetization reversal of electrodeposited Co/Cu superlattices are investigated for a range of Cu spacer thicknesses. The multilayers showing vanishing GMR exhibit a cooperative spin behaviour, which is similar to that exhibited by thin ferromagnetic films with in-plane fourfold anisotropy. Tn contrast, superlattices with a substantial GMR demonstrate partially coupled noncollinear spin configurations, which are probably responsible for the observed giant magnetoresistance phenomenon. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Russian Acad Sci, Inst Solid State Phys, Chernogolovka 142432, Russia. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Univ Maryland, Dept Mat & Nucl Engn, College Pk, MD 20742 USA. RP Nikitenko, VI (reprint author), Russian Acad Sci, Inst Solid State Phys, Chernogolovka 142432, Russia. EM nikiten@issp.ac.ru RI Salamanca-Riba, Lourdes/B-3785-2009; Shull, Robert/F-5971-2013 OI Salamanca-Riba, Lourdes/0000-0001-8155-6403; NR 4 TC 4 Z9 4 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0304-8853 J9 J MAGN MAGN MATER JI J. Magn. Magn. Mater. PD JUN PY 1999 VL 198-99 BP 477 EP 479 DI 10.1016/S0304-8853(98)01151-2 PG 3 WC Materials Science, Multidisciplinary; Physics, Condensed Matter SC Materials Science; Physics GA 204TE UT WOS:000080779600151 ER PT J AU Nikitenko, VI Gornakov, VS Dedukh, LM Khapikov, AF Shapiro, AJ Shull, RD Chaiken, A AF Nikitenko, VI Gornakov, VS Dedukh, LM Khapikov, AF Shapiro, AJ Shull, RD Chaiken, A TI Asymmetry of the remagnetization processes in exchange-biased NiFe NiO bilayers SO JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS LA English DT Article; Proceedings Paper CT 3rd International Symposium on Metallic Multilayers (MML98) held Jointly with the EMRS Symposium on Magnetic Ultrathin Films and Ultrathin Film Nanostructures CY JUN 14-19, 1998 CL VANCOUVER, CANADA DE ferro antiferromagnetic bilayer; unidirectional anisotropy; remagnetization; domains AB The magnetization reversal of NiFe/NiO exchange-coupled films with direct (NiFe/NiO) and inverse (NiO/NiFe) deposition ordering of the ferro- and antiferromagnetic layers onto the MgO substrate were investigated by means of the magneto-optical indicator film technique and vibrating sample magnetometry. Processes of thr domain formation and growth as well as the magnitude of the macroscopic coercive force were found to depend drastically on the growth order. oreover all of our bilayers were characterized by an asymmetry in the activity of crystal lattice defects as domain wall nucleation centers. The results are discussed in terms of variations in the real crystal structure of the antiferromagnetic layer. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Russian Acad Sci, Inst Solid State Phys, Chernogolovka 142432, Moscow Dist, Russia. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Hewlett Packard Lab, Palo Alto, CA 94304 USA. RP Nikitenko, VI (reprint author), Russian Acad Sci, Inst Solid State Phys, Chernogolovka 142432, Moscow Dist, Russia. EM nikiten@issp.ac.ru RI Shull, Robert/F-5971-2013 NR 6 TC 3 Z9 3 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0304-8853 J9 J MAGN MAGN MATER JI J. Magn. Magn. Mater. PD JUN PY 1999 VL 198-99 BP 500 EP 502 DI 10.1016/S0304-8853(98)01197-4 PG 3 WC Materials Science, Multidisciplinary; Physics, Condensed Matter SC Materials Science; Physics GA 204TE UT WOS:000080779600158 ER PT J AU Dariel, MP Ratzker, M Eichmiller, FC AF Dariel, MP Ratzker, M Eichmiller, FC TI Acid-assisted consolidation of powder compacts: cold-welding or cold sintering SO JOURNAL OF MATERIALS SCIENCE LA English DT Article ID POROSITY; PARAMETERS AB Silver powder that has been treated in dilute fluoroboric acid solution and compacted at room temperature displays surprisingly elevated flexural and even tensile strength. The density and mechanical strength values increase with increasing compaction pressure. The flexural strength and the elastic moduli of silver powder compacted at 1 GPa, as determined by sound velocity measurements, reach values comparable to those of bulk silver. The results can be tentatively interpreted either in terms of an ambient temperature self-soldering effect of silver in the presence of the fluoroboric acid, acting as a fluxing agent, or as cold liquid-phase sintering in an aqueous liquid medium. (C) 1999 Kluwer Academic Publishers. C1 Ben Gurion Univ Negev, Dept Mat Engn, IL-84105 Beer Sheva, Israel. NIST, Amer Dent Assoc, Paffenbarger Res Ctr, Gaithersburg, MD 20899 USA. RP Dariel, MP (reprint author), Ben Gurion Univ Negev, Dept Mat Engn, IL-84105 Beer Sheva, Israel. NR 15 TC 2 Z9 2 U1 3 U2 5 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0022-2461 J9 J MATER SCI JI J. Mater. Sci. PD JUN 1 PY 1999 VL 34 IS 11 BP 2601 EP 2607 DI 10.1023/A:1004652716470 PG 7 WC Materials Science, Multidisciplinary SC Materials Science GA 211VD UT WOS:000081181800016 ER PT J AU Telles, EM Odashima, H Zink, LR Evenson, KM AF Telles, EM Odashima, H Zink, LR Evenson, KM TI Optically pumped FIR laser lines from CH3OH: New laser lines, frequency measurements, and assignments SO JOURNAL OF MOLECULAR SPECTROSCOPY LA English DT Article ID FAR-INFRARED LASER; CO2-LASER LINES; METHANOL; SPECTROSCOPY AB We report the identification and characterization of eight new FIR laser lines from methanol (CH3OH) in the range 48.4 to 453.7 mu m pumped by sequence and hot bands of a cw CO2 laser. Frequency measurements for most of the new FIR laser lines and from previously reported ones were obtained in the range 0.6-6.8 THz with a one-sigma reproducibility of two parts in 10(7). We propose an assignment of energy levels for two of the new laser lines and for five pumped by 10R(46) previously reported. The high frequency lines with absorption centers outside of the tuning range of the CO2 laser pump showed doublets. These were used to evaluate the offsets of the CO2 absorption transitions. C1 Natl Inst Stand & Technol, Div Time & Frequency, Boulder, CO 80303 USA. Toyama Univ, Dept Phys, Toyama 930, Japan. RP Telles, EM (reprint author), Natl Inst Stand & Technol, Div Time & Frequency, 325 Broadway, Boulder, CO 80303 USA. NR 17 TC 21 Z9 22 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 1999 VL 195 IS 2 BP 360 EP 366 DI 10.1006/jmsp.1999.7834 PG 7 WC Physics, Atomic, Molecular & Chemical; Spectroscopy SC Physics; Spectroscopy GA 200XL UT WOS:000080565400019 ER PT J AU Winton, M AF Winton, M TI Polar water column stability SO JOURNAL OF PHYSICAL OCEANOGRAPHY LA English DT Article ID WINTER MIXED LAYER AB An expression is derived for the surface salt input needed to induce complete connective overturning of a polar water column consisting of 1) a layer of sea ice, 2) a freezing temperature mixed layer, 3) a pycnocline with linearly varying temperature and salinity, and 4) deep water with fixed temperature and salinity. This quantity has been termed the bulk stability by Martinson. The bulk stability is found to consist of three components. The first two make up Martinson's salt deficit and are the salt input needed to increase the density of the mixed layer and the pycnocline layer to that of the deep water (the mired layer stability and pycnocline layer stability, respectively). The third component is Martinson's thermal barrier: the potential fur pycnocline heat to melt ice, reducing the surface salinity. It is found that when the pycnocline density gradient due to temperature offsets more than one half of that due to salinity, the pycnocline lover stability is negative, Consequently. it is possible for a stably stratified water column to have zero or negative bulk stability. C1 NOAA, Geophys Fluid Dynam Lab, Princeton, NJ 08542 USA. RP Winton, M (reprint author), NOAA, Geophys Fluid Dynam Lab, POB 308, Princeton, NJ 08542 USA. NR 4 TC 1 Z9 1 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-3670 J9 J PHYS OCEANOGR JI J. Phys. Oceanogr. PD JUN PY 1999 VL 29 IS 6 BP 1368 EP 1371 DI 10.1175/1520-0485(1999)029<1368:PWCS>2.0.CO;2 PG 4 WC Oceanography SC Oceanography GA 210DU UT WOS:000081090500020 ER PT J AU Kane, J AF Kane, J TI Persistent spatial and temporal abundance patterns for the late-stage copepodites of Centropages typicus (Copepoda : Calanoida) in the US Northeast Continental Shelf Ecosystem SO JOURNAL OF PLANKTON RESEARCH LA English DT Article ID GEORGES BANK; LIFE-HISTORY; YORK BIGHT; ZOOPLANKTON; FINMARCHICUS; VARIABILITY; ATLANTIC; CALANUS; RATES AB The annual cycle of abundance and the monthly distributions of the copepod Centropages typicus are described for US Northeast Continental Shelf waters from samples collected on broad-scale plankton surveys during 1977-87. High numbers of the copepod were captured throughout the region during the autumn months in weak south-north and onshore-offshore abundance gradients. The highest individual station densities were found near the mouth of the major estuaries and the heaviest broad-scale concentrations were usually located where bottom depth ranged from 20 to 39 m. Numbers declined throughout the ecosystem after winter arrived, less so in the southern half of the region where C.typicus abundance remained high year round in nearshore and midshelf waters between New York City and Chesapeake Bay. The copepod's abundance fell to much lower levels further north in the Georges Bank and Gulf of Maine subareas, and disappeared entirely from shelf waters in the northernmost offshore region until summer. Interannual abundance variability was substantial, but no long-term trend was detected. Analyses of samples collected from 1988 to 1996 on Georges Bank during early autumn indicate that abundance levels of C.typicus have been high here in the 1990s, completely recovered from low density values measured there in 1986 and 1987. Temperature and food availability were found to be the key factors that determine the copepod's distribution and annual abundance cycle. Mean abundance was high throughout the ecosystem where surface temperature was >9 degrees C and in regions where annual mean chlorophyll levels exceeded 1 mg m(-3). The copepod's abundance appeared to be independent from variation in water column salinity. C1 Natl Marine Fisheries Serv, NOAA, Narragansett, RI 02882 USA. RP Kane, J (reprint author), Natl Marine Fisheries Serv, NOAA, 28 Tarzwell Dr, Narragansett, RI 02882 USA. NR 28 TC 6 Z9 6 U1 2 U2 8 PU OXFORD UNIV PRESS PI OXFORD PA GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND SN 0142-7873 J9 J PLANKTON RES JI J. Plankton Res. PD JUN PY 1999 VL 21 IS 6 BP 1043 EP 1064 PG 22 WC Marine & Freshwater Biology; Oceanography SC Marine & Freshwater Biology; Oceanography GA 207EQ UT WOS:000080923500003 ER PT J AU Beaucage, G Rane, S Schaefer, DW Long, G Fischer, D AF Beaucage, G Rane, S Schaefer, DW Long, G Fischer, D TI Morphology of polyethylene-carbon black composites SO JOURNAL OF POLYMER SCIENCE PART B-POLYMER PHYSICS LA English DT Article DE small-angle scattering; polyethylene; poly(methyl methacrylate); carbon black; filler; composite; conductivity; percolation ID SMALL-ANGLE SCATTERING; POWER-LAW APPROACH; X-RAY; DIFFUSION FLAMES; ROUGH AB Carbon black is a common polymer additive that is used for reinforcement and for its ability to enhance physical properties, such as conductivity. This article pertains to an X-ray scattering (SAXS) study of a conductive grade of carbon black and carbon black-polymer composites. The scattering pattern for such blacks displays a surface-fractal-like power-law decay over many decades in scattering vector q. It is often assumed that small-angle scattering from carbon black aggregates can be described in terms of surface-fractal models, related to particles with fractally rough surfaces. Such self-similar surface roughness is usually easy to identify by microscopy; however, electron microscopy from these blacks fails to support this assumption. It is proposed here that this apparent surface-fractal scattering actually represents a more complicated morphology, including overlapping structural features and a power-law scaling of polydispersity. One use of conductive black-polyethylene composites is in circuit protection devices where resistive heating leads to a reversible association of carbon black aggregates that controls switching between a conductive and a nonconductive state. Scattering can be used as an in situ tool to observe the morphological signature of this reversible structural change. Scattering patterns support a model for this switching based on local enhancement of concentration and the formation of linear agglomerates associated with the matrix polymer's semicrystalline morphology. (C) 1999 John Wiley & Sons, Inc. C1 Univ Cincinnati, Cincinnati, OH 45221 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20885 USA. RP Beaucage, G (reprint author), Univ Cincinnati, Cincinnati, OH 45221 USA. NR 37 TC 49 Z9 50 U1 1 U2 15 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 JUN 1 PY 1999 VL 37 IS 11 BP 1105 EP 1119 DI 10.1002/(SICI)1099-0488(19990601)37:11<1105::AID-POLB6>3.0.CO;2-5 PG 15 WC Polymer Science SC Polymer Science GA 188FX UT WOS:000079837100006 ER PT J AU Kelly, JR AF Kelly, JR TI Clinically relevant approach to failure testing of all-ceramic restorations SO JOURNAL OF PROSTHETIC DENTISTRY LA English DT Article; Proceedings Paper CT 80th Annual Meeting of the Academy-of-Prosthodontics CY MAY, 1998 CL COLORADO SPRINGS, CO SP Acad Prosthodont ID OCCLUSAL FORCES; DENTAL CERAMICS; BITE FORCE; COMPRESSIVE STRENGTH; ALUMINOUS PORCELAIN; CROWNS; WEAR; POPULATION; FREQUENCY; CONTACTS AB Statement of problem. One common test of single-unit restorations involves applying loads to clinically realistic specimens through spherical indenters, or equivalently, loading curved incisal edges against flat compression platens. As knowledge has become available regarding clinical failure mechanisms and the behavior of in vitro tests, it is possible to constructively question the clinical validity of such failure testing and to move toward developing more relevant test methods. Purpose. This article reviewed characteristics of the traditional load-to-failure test, contrasted these with characteristics of clinical failure for all-ceramic restorations, and sought to explain the discrepancies. Literature regarding intraoral conditions was reviewed to develop an understanding of how laboratory testing could be revised. Variables considered to be important in simulating clinical conditions were described, along with their recent laboratory evaluation. Conclusions. Traditional fracture tests of single unit all-ceramic prostheses are inappropriate, because they do not Create failure mechanisms seen in retrieved clinical specimens. Validated tests are needed to elucidate the role(s) that cement systems, bonding, occlusion, and even metal copings play in the success of fixed prostheses and to make meaningful comparisons possible among novel ceramic and metal substructures. Research over the past 6 years has shown that crack systems mimicking clinical failure can be produced in all-ceramic restorations under appropriate conditions. C1 NIST, Dent & Med Mat Grp, Gaithersburg, MD 20899 USA. USN, Sch Dent, Dent Res Inst, Bethesda, MD USA. RP Kelly, JR (reprint author), NIST, Dent & Med Mat Grp, 100 Bur Dr,Mail Stop 8545, Gaithersburg, MD 20899 USA. EM robert.kelly@nist.gov NR 62 TC 326 Z9 334 U1 0 U2 15 PU MOSBY-ELSEVIER PI NEW YORK PA 360 PARK AVENUE SOUTH, NEW YORK, NY 10010-1710 USA SN 0022-3913 EI 1097-6841 J9 J PROSTHET DENT JI J. Prosthet. Dent. PD JUN PY 1999 VL 81 IS 6 BP 652 EP 661 DI 10.1016/S0022-3913(99)70103-4 PG 10 WC Dentistry, Oral Surgery & Medicine SC Dentistry, Oral Surgery & Medicine GA 207AF UT WOS:000080912600002 PM 10347352 ER PT J AU Cahn, JW Han, SC McFadden, GB AF Cahn, JW Han, SC McFadden, GB TI Anisotropy of interfaces in an ordered HCP binary alloy SO JOURNAL OF STATISTICAL PHYSICS LA English DT Article DE diffuse interfaces; hexagonal close packing; anisotropy; mean-field theory; Allen-Cahn equation; interphase boundaries; antiphase boundaries; surface energy; discrete free energy AB A multiple-order-parameter mean-field theory of ordering on a binary hexagonal-close-packed (HCP) crystal structure is developed, and adapted to provide a continuum formulation that incorporates the underlying symmetries of the HCP crystal in both the bulk and gradient energy terms of the free energy. The work is an extension of the previous treatment by Braun ct al. [Phil. Trans. Roy.. Sec. Lend. A 355:1787 (1997)] of order-disorder transitions on a face-centered-cubic crystal(FCC) lattice. The theory is used to compute the orientation dependence of the structure and energy of interphase and antiphase boundaries in ordering to the Cd, Mg and CdMg structures, which are the HCP analogs of Cu, Au and CuAu structures in FCC. As in the corresponding FCC case, the multiple order parameters do not form a vector. Anisotropy is a natural consequence of the underlying crystal symmetries and the multiple-order-parameter continuum formation presented here. The isotropy transverse to the sixfold axis expected For a scalar order parameter is not found. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Montgomery Blair High Sch, Silver Spring, MD 20910 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 16 TC 10 Z9 10 U1 0 U2 4 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0022-4715 J9 J STAT PHYS JI J. Stat. Phys. PD JUN PY 1999 VL 95 IS 5-6 BP 1337 EP 1360 DI 10.1023/A:1004583324097 PG 24 WC Physics, Mathematical SC Physics GA 233TY UT WOS:000082444400023 ER PT J AU Ostashev, VE Goedecke, GH Wood, R Auvermann, H Clifford, SF AF Ostashev, VE Goedecke, GH Wood, R Auvermann, H Clifford, SF TI Sound scattering cross-section in a stratified moving atmosphere SO JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA LA English DT Article AB For a realistic model of a stratified moving atmosphere with arbitrary vertical profiles of the adiabatic sound speed and wind velocity vector, an equation is derived for the sound scattering cross-section per unit volume, sigma, as a function of apparent scattering angle Theta(0). The effects of these profiles on sigma are studied numerically. It is shown that if the wind velocity is zero, but the adiabatic sound speed varies with height, then a can be affected significantly for Theta(0)<110 degrees. Furthermore, if the wind velocity varies with height, but the adiabatic sound speed does not, then a can be affected significantly for Theta(0)<110 degrees as well as Theta(0) near 180 degrees. These and other, numerical calculations have shown that in many cases acoustic remote sensing of the structure parameters of temperature and wind velocity fluctuations in the atmosphere should be based on the derived equation for a rather than on that used in the literature. The derived equation for sigma is also compared to those obtained by Clifford and Brown [J. Acoust. Soc. Am. 55, 929-933 (1974)] and by Ye [J. Acoust. Soc. Am. 102, 754-758 (1997)] for a model of a stratified moving atmosphere as two homogeneous layers in relative motion. It is explained why the predictions by Clifford and Brown are different from those by Ye. (C) 1999 Acoustical Society of America. [S0001-4966(99)03206-3]. C1 New Mexico State Univ, Dept Phys, Las Cruces, NM 88003 USA. USA, Res Lab, Adelphi, MD 20783 USA. NOAA, ERL, ETL, Boulder, CO 80303 USA. RP Ostashev, VE (reprint author), New Mexico State Univ, Dept Phys, Las Cruces, NM 88003 USA. NR 9 TC 3 Z9 3 U1 0 U2 1 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0001-4966 J9 J ACOUST SOC AM JI J. Acoust. Soc. Am. PD JUN PY 1999 VL 105 IS 6 BP 3115 EP 3125 DI 10.1121/1.424642 PG 11 WC Acoustics; Audiology & Speech-Language Pathology SC Acoustics; Audiology & Speech-Language Pathology GA 204RN UT WOS:000080778100014 ER PT J AU Garner, ST AF Garner, ST TI Blocking and frontogenesis by two-dimensional terrain in baroclinic flow. Part I: Numerical experiments SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID UPPER BOUNDARY-CONDITION; ENGLAND COASTAL FRONTOGENESIS; FRONTS; RIDGE; CYCLOGENESIS; OROGRAPHY; MODELS; DISTURBANCES; ATMOSPHERE; TOPOGRAPHY AB The shallow atmospheric fronts that develop in the early winter along the east coast of North America have been attributed, in various modeling and observational studies, to the land-sea contrasts in both surface heating and friction. However, typical synoptic conditions are such that these "coastal" fronts could also be a type of upstream influence by the Appalachian Mountain chain. Generalized models have suggested that relatively cold air can become trapped on the windward side of a mountain range during episodes of warm advection without a local contribution from differential surface fluxes. Such a process was proposed decades ago in a study of observations along the coast of Norway. Could coastal frontogenesis be primarily a consequence of a mountain circulation acting on the large-scale temperature gradient? A two-dimensional, terrain-following numerical model is used to find conditions under which orography may be sufficient to cause blocking and upstream frontogenesis in a baroclinic environment. The idealized basic flow is taken to have constant vertical shear parallel to a topographic ridge and a constant perpendicular wind that advects warm or cold temperatures toward the ridge. Land-sea contrasts are omitted. In the observed cases, the mountain is "narrow" in the sense that the Rossby number is large. This by itself increases the barrier effect, but the experiments show that large-scale warm advection is still crucial for blocking. For realistic choices of ambient static stability and baroclinicity, the flow can be blocked by a range like the northern Appalachians if the undisturbed incident wind speed is around 10 m s(-1). Cold advection weakens the barrier effect. The long-term behavior of the front in strongly blocked cases is described and compared to observations. Because of the background rotation and large-scale temperature advection, blocked solutions cannot become steady in the assumed environment. However, the interface between blocked and unblocked fluid can settle into a balanced configuration in some cases. A simple argument suggests that, in the absence of dissipation, the frontal slope should be similar to that of the ambient "absolute momentum" surfaces. C1 Princeton Univ, NOAA, GFDL, Princeton, NJ 08542 USA. RP Princeton Univ, NOAA, GFDL, POB 308, Princeton, NJ 08542 USA. EM stg@gfdl.gov NR 43 TC 4 Z9 4 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-4928 EI 1520-0469 J9 J ATMOS SCI JI J. Atmos. Sci. PD JUN 1 PY 1999 VL 56 IS 11 BP 1495 EP 1508 DI 10.1175/1520-0469(1999)056<1495:BAFBTD>2.0.CO;2 PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 204JY UT WOS:000080762200004 ER PT J AU Garner, ST AF Garner, ST TI Blocking and frontogenesis by two-dimensional terrain in baroclinic flow. Part II: Analysis of flow stagnation mechanisms SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID MESOSCALE MOUNTAINS; WAVES AB Numerical solutions presented in a companion paper show that two-dimensional mesoscale terrain becomes a much stronger barrier to a continuously stratified Bow when the flow contains warm advection. Here it is shown that this baroclinic enhancement is a strictly nonlinear phenomenon. The linear analysis indicates a weakening of the upstream response in warm advection. However, a weakly nonlinear analysis shows that baroclinicity facilitates blocking in warm advection by strengthening the nonlinearity in the cross-mountain momentum equation in such a way as to amplify the vertical shear on the windward flank of the ridge. This is enough to send the flow past the blocking threshold even when conditions over the mountain are too linear to produce wave breaking. A more intuitive mechanism whereby the upstream static stability is increased by the nonlinearity in the temperature equation is found to be much less important. C1 Princeton Univ, NOAA, GFDL, Princeton, NJ 08542 USA. RP Garner, ST (reprint author), Princeton Univ, NOAA, GFDL, POB 308, Princeton, NJ 08542 USA. NR 16 TC 2 Z9 2 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 JUN 1 PY 1999 VL 56 IS 11 BP 1509 EP 1523 DI 10.1175/1520-0469(1999)056<1509:BAFBTD>2.0.CO;2 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 204JY UT WOS:000080762200005 ER PT J AU Held, IM Schneider, T AF Held, IM Schneider, T TI The surface branch of the zonally averaged mass transport circulation in the troposphere SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID GENERALIZED ELIASSEN-PALM; MEAN FLOWS; OCEAN; EDDIES; MODELS; WAVES AB The near-surface branch of the overturning mass transport circulation in the troposphere, containing the equatorward flow, is examined in isentropic and geometric coordinates. A discussion of the zonal momentum balance within isentropic layers shows that the equatorward how at a given latitude is confined to isentropic layers that typically intersect the surface at that latitude. As a consequence of mass transport within the surface mixed layer, much of the equatorward flow occurs in layers with potential temperatures below the mean surface potential temperature. In the conventional transformed Eulerian mean formulation for geometric coordinates, the surface branch of the overturning circulation is represented in an unrealistic manner: streamlines of the residual circulation do not close above the surface. A modified residual circulation is introduced that is free from this defect and has the additional advantage that its computation, unlike that of the conventional residual circulation, does not require division by the static stability, which may approach zero in the planetary boundary layer. It is then argued that cold air advection by the residual circulation is responsible for the formation of surface inversions at all latitudes in idealized GCMs with weak thermal damping. Also included is a discussion of how a general circulation theory for the troposphere must be built upon a theory for the near-surface meridional mass fluxes. C1 Princeton Univ, NOAA, Geophys Fluid Dynam Lab, Princeton, NJ 08542 USA. Princeton Univ, Atmospher & Ocean Sci Program, Princeton, NJ 08542 USA. RP Held, IM (reprint author), Princeton Univ, NOAA, Geophys Fluid Dynam Lab, POB 308, Princeton, NJ 08542 USA. RI Schneider, Tapio /A-7038-2014 OI Schneider, Tapio /0000-0001-5687-2287 NR 15 TC 113 Z9 113 U1 0 U2 8 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 JUN 1 PY 1999 VL 56 IS 11 BP 1688 EP 1697 DI 10.1175/1520-0469(1999)056<1688:TSBOTZ>2.0.CO;2 PG 10 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 204JY UT WOS:000080762200016 ER PT J AU Bishop, CH Toth, Z AF Bishop, CH Toth, Z TI Ensemble transformation and adaptive observations SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID OPTIMAL EXCITATION; DATA ASSIMILATION; SINGULAR VECTORS; BAROCLINIC WAVES; MODEL; PERTURBATIONS AB Suppose that the geographical and temporal resolution of the observational network could be changed on a daily basis. Of all the possible deployments of observational resources, which particular deployment would minimize expected forecast error? The ensemble transform technique answers such questions by using nonlinear ensemble forecasts to rapidly construct ensemble-based approximations to the prediction error covariance matrices associated with a wide range of different possible deployments of observational resources. From these matrices, estimates of the expected forecast error associated with each distinct deployment of observational resources are obtained. The deployment that minimizes the chosen measure of forecast error is deemed optimal. The technique may also be used to find the perturbation that evolves into the leading eigenvector or singular vector of an ensemble-based prediction error covariance matrix. This time-evolving perturbation "explains" more of the ensemble-based prediction error variance than any other perturbation. It may be interpreted as the fastest growing perturbation on the subspace of ensemble perturbations. The ensemble-based approximations to the prediction error covariance matrices are constructed from transformation matrices derived from estimates of the analysis error covariance matrices associated with each possible deployment of observational resources. The authors prove that the ensemble transform technique would precisely recover the prediction error covariance matrices associated with each possible deployment of observational resources provided that (i) estimates of the analysis error covariance matrix were precise, (ii) the ensemble perturbations span the vector space of all possible perturbations, and (iii) the evolution of errors were linear and perfectly modeled. In the absence of such precise information, the ensemble transform technique links available information on analysis error covariances associated with different observational networks with error growth estimates contained in the ensemble forecast to estimate the optimal configuration of an adaptive observational network. Tests of the technique will be presented in subsequent publications. Here, the objective is to describe the theoretical basis of the technique and illustrate it with an example from the fronts and Atlantic Storm Tracks Experiment (FASTEX). C1 Penn State Univ, Dept Meteorol, University Pk, PA 16802 USA. NCEP, GSC, Camp Springs, MD USA. RP Bishop, CH (reprint author), Penn State Univ, Dept Meteorol, 520 Walker Bldg, University Pk, PA 16802 USA. RI Toth, Zoltan/I-6624-2015 OI Toth, Zoltan/0000-0002-9635-9194 NR 31 TC 164 Z9 189 U1 0 U2 15 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 JUN 1 PY 1999 VL 56 IS 11 BP 1748 EP 1765 DI 10.1175/1520-0469(1999)056<1748:ETAAO>2.0.CO;2 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 204JY UT WOS:000080762200020 ER PT J AU Germer, TA Asmail, CC AF Germer, TA Asmail, CC TI Polarization of light scattered by microrough surfaces and subsurface defects SO JOURNAL OF THE OPTICAL SOCIETY OF AMERICA A-OPTICS IMAGE SCIENCE AND VISION LA English DT Article ID OUT-OF-PLANE; MUELLER MATRIX; ROUGH SURFACES; POLARIMETRY; HAZE AB The polarization of light scattered into directions out of the plane of incidence for 532-nm light incident at 45 degrees with p polarization was measured from rough silicon, rough titanium nitride, polished fused silica and glass ceramic, and ground and incompletely polished black glass. Models for polarized light scattering from microroughness, subsurface defects, and facets are reviewed. The measurements demonstrate the validity of the models and the utility of polarized light scattering measurements for distinguishing between roughness and defects. [S0740-3232(99)02506-5]. C1 NIST, Opt Technol Div, Gaithersburg, MD 20899 USA. RP Germer, TA (reprint author), NIST, Opt Technol Div, Gaithersburg, MD 20899 USA. NR 32 TC 53 Z9 59 U1 2 U2 16 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 0740-3232 J9 J OPT SOC AM A JI J. Opt. Soc. Am. A-Opt. Image Sci. Vis. PD JUN PY 1999 VL 16 IS 6 BP 1326 EP 1332 DI 10.1364/JOSAA.16.001326 PG 7 WC Optics SC Optics GA 198YQ UT WOS:000080452500012 ER PT J AU Vecchione, M Young, RE Donovan, DT Rodhouse, PG AF Vecchione, M Young, RE Donovan, DT Rodhouse, PG TI Reevaluation of coleoid cephalopod relationships based on modified arms in the Jurassic coleoid Mastigophora SO LETHAIA LA English DT Article DE Cephalopoda; coleoid; Mastigophora; decapod; vampyromorph; tentacles; soft-tissue fossil AB Mastigophora brevipinnis Owen, 1856, is a 'fossil teuthid' presently considered to be a member of the coleoid cephalopod Suborder Loligosepiina Jeletzky, which in turn has been placed by various authors in or near the Vampyromorpha Grimpe. Recent morphological and biochemical analyses indicate that vampyromorphs are more closely related to the Octopoda than to the Decapodiformes. Fossils of Mastigophora from the Oxford Clay (Jurassic: Callovian) show soft-tissue preservation and evidence of arm crown specialization. Some of these fossils have up to eight short, thick arms with circular sucker-like structures and filiform distal extensions, plus what appear to be the bases of two thinner ventrolateral arms. The latter lack proximal suckers : and curve medially to insert into the arm crown, similar to the tentacles that are the modified ventrolateral arms of living squids and cuttlefishes. This suggests that the thinner structures were decapod-like tentacles. If Mastigophora had tentacles homologous with those of modern decapods, then it was a decapod, because this synapomorphy defines the Decapodiformes. This indication of decapod affinities for Mastigophora brings into question the relationships of the other 'fossil teuthids'. The inferred relationship of the Loligosepiina, including Mastigophora, with the Vampyromorpha, based largely on similarities of gladius morphology with that of living Vampyroteuthis, may reflect shared plesiomorphic characters. C1 Natl Museum Nat Hist, NMFS Systemat Lab, Washington, DC 20560 USA. Univ Hawaii, Dept Oceanog, Honolulu, HI 96822 USA. UCL, Dept Geol Sci, London WC1E 6BT, England. British Antarctic Survey, Cambridge CB3 0ET, England. RP Vecchione, M (reprint author), Natl Museum Nat Hist, NMFS Systemat Lab, Washington, DC 20560 USA. EM vecchione.michael@nmnh.si.edu; ryoung@hawaii.edu; ucfb03d@ucl.ac.uk; p.rodhouse@bas.ac.uk NR 25 TC 15 Z9 16 U1 0 U2 2 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 0024-1164 J9 LETHAIA JI Lethaia PD JUN PY 1999 VL 32 IS 2 BP 113 EP 118 PG 6 WC Paleontology SC Paleontology GA 234BJ UT WOS:000082463700004 ER PT J AU D'Sa, EJ Steward, RG Vodacek, A Blough, NV Phinney, D AF D'Sa, EJ Steward, RG Vodacek, A Blough, NV Phinney, D TI Determining optical absorption of colored dissolved organic matter in seawater with a liquid capillary waveguide SO LIMNOLOGY AND OCEANOGRAPHY LA English DT Article ID TOTAL REFLECTION; WATERS; OCEAN; CELL; SEA; UV AB Optical absorption spectra of 0.2-mu m filtered seawater samples originating from diverse oceanic and coastal waters were measured with a long pathlength capillary waveguide; results were compared with those of three different laboratory spectrophotometers. The 0.5-m-long 550-mu m (inside diameter) aqueous waveguide uses only 120 mu l of filtered seawater. making it convenient for use in flow-through cells or when sample volumes are restricted. Source light propagates inside the capillary waveguide by total internal reflection because of the lower refractive index of the waveguide walls with respect to the aqueous core. The absorption coefficient of colored dissolved organic matter (CDOM) at 355 nm and S, the slope of the log-linearized CDOM absorption spectra, were determined for all samples. The CDOM absorption spectra measured by the capillary waveguide closely matched that measured by spectrophotometers for CDOM concentrations varying over an order of magnitude. The deviations between the absorption spectra obtained with the capillary waveguide and those obtained with the standard spectrophotometers increased with decreasing total absorption and with increase in wavelength, presumably because of the greater baseline offsets observed in the capillary waveguide. The offsets are due to differences in refractive indices between the seawater samples and the freshwater reference. With a suitable reference, the capillary waveguide will be very useful for monitoring surface seawater CDOM absorption semicontinuously. C1 NOAA, Off Res & Applicat, Camp Springs, MD 20746 USA. Univ S Florida, Dept Marine Sci, St Petersburg, FL 33701 USA. Univ Maryland, Dept Chem & Biochem, College Pk, MD 20742 USA. Bigelow Lab Ocean Sci, Boothbay Harbor, ME 04575 USA. RP D'Sa, EJ (reprint author), NOAA, Off Res & Applicat, NESDIS-E-RA3,5200 Auth Rd, Camp Springs, MD 20746 USA. RI Blough, Neil/B-7727-2009; Vodacek, Anthony/F-1585-2011 OI Vodacek, Anthony/0000-0001-9196-0928 NR 15 TC 58 Z9 58 U1 0 U2 19 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 JUN PY 1999 VL 44 IS 4 BP 1142 EP 1148 PG 7 WC Limnology; Oceanography SC Marine & Freshwater Biology; Oceanography GA 228QY UT WOS:000082148200017 ER PT J AU Wang, H Newstein, MC Krishnan, A Balsara, NP Garetz, BA Hammouda, B Krishnamoorti, R AF Wang, H Newstein, MC Krishnan, A Balsara, NP Garetz, BA Hammouda, B Krishnamoorti, R TI Ordering kinetics and alignment of block copolymer lamellae under shear flow SO MACROMOLECULES LA English DT Article ID DIBLOCK COPOLYMER; POLYSTYRENE-POLYISOPRENE; TRANSITION; DISORDER; MELT; ORIENTATION; PHASE; BIREFRINGENCE; SCATTERING; MICROSTRUCTURE AB The effect of large-amplitude oscillatory shear flow on a concentrated block copolymer solution with lamellar order was studied by in-situ small-angle neutron scattering. Microstructural changes were studied as a function of temperature, frequency of the oscillatory flow field, and thermal history prior to turning on the shear field. We find that the alignment path depends mainly on thermal history prior to turning on the shear field and is independent of frequency and temperature. At long times, the lamellae were aligned parallel to the shearing plates, regardless of frequency, temperature, and thermal history. We refer to this as the parallel orientation. Monotonic changes from the unaligned to the aligned state were found when the shear field was turned on after the sample was completely ordered. The alignment kinetics, in this case, occurs in two stages. The first stage consists of a rapid rotation of the grains so that the lamellar normals lie in the velocity gradient-vorticity plane. This is followed by a slower process wherein the lamellar normals get increasingly localized in the velocity gradient direction. We also studied ordering kinetics under shear, by turning on the shear field before significant ordering had taken place. In this case, the first stage of ordering resulted in the formation of lamellae aligned perpendicular to the shearing plates in addition to the parallel lamellae, regardless of temperature and frequency. Eventually the perpendicular lamellae were transformed to parallel lamellae via an undulation instability. C1 Polytech Univ, Dept Chem Engn, Brooklyn, NY 11201 USA. Polytech Univ, Dept Chem, Brooklyn, NY 11201 USA. Polytech Univ, Dept Mat Sci, Brooklyn, NY 11201 USA. Polytech Univ, Dept Elect Engn, Brooklyn, NY 11201 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Univ Houston, Dept Chem Engn, Houston, TX 77204 USA. RP Balsara, NP (reprint author), Polytech Univ, Dept Chem Engn, 6 Metrotech Ctr, Brooklyn, NY 11201 USA. RI Krishnamoorti, Ramanan/F-7914-2011 OI Krishnamoorti, Ramanan/0000-0001-5831-502X NR 49 TC 27 Z9 30 U1 0 U2 7 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0024-9297 J9 MACROMOLECULES JI Macromolecules PD JUN 1 PY 1999 VL 32 IS 11 BP 3695 EP 3711 DI 10.1021/ma981226d PG 17 WC Polymer Science SC Polymer Science GA 203DA UT WOS:000080691300022 ER PT J AU Lin, EK Kolb, R Satija, SK Wu, WL AF Lin, EK Kolb, R Satija, SK Wu, WL TI Reduced polymer mobility near the polymer solid interface as measured by neutron reflectivity SO MACROMOLECULES LA English DT Article ID INITIAL-STAGES; FILMS; INTERDIFFUSION; DYNAMICS; TEMPERATURE; MELT AB Neutron reflectometry is used to measure polymer mobility over distances less than 200 Angstrom as a function of distance from an attractive solid surface and molecular size. Effective diffusion coefficients, D-eff, are determined from the rates of interdiffusion between supported bilayers of deuterated and hydrogenated poly(methyl methacrylate) (PMMA). The thickness of the d-PMMA layer is varied from less than the radius of gyration, R-g of the bulk polymer to 11R(g) for three molecular weight pairs of polymers. D-eff dramatically decreases in samples with d-PMMA layers less than 3R(g) thick and approaches bulk interdiffusion rates from layers greater than 5R(g) thick. C1 Natl Inst Stand & Technol, Div Polymers, Gaithersburg, MD 20899 USA. Natl Inst Stand & Technol, Ctr Neutron Res, Gaithersburg, MD 20899 USA. RP Lin, EK (reprint author), Natl Inst Stand & Technol, Div Polymers, Gaithersburg, MD 20899 USA. NR 24 TC 125 Z9 130 U1 3 U2 25 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0024-9297 J9 MACROMOLECULES JI Macromolecules PD JUN 1 PY 1999 VL 32 IS 11 BP 3753 EP 3757 DI 10.1021/ma9814604 PG 5 WC Polymer Science SC Polymer Science GA 203DA UT WOS:000080691300029 ER PT J AU Weinberg, JR AF Weinberg, JR TI Age-structure, recruitment, and adult mortality in populations of the Atlantic surfclam, Spisula solidissima, from 1978 to 1997 SO MARINE BIOLOGY LA English DT Article ID SUPPLY-SIDE ECOLOGY; MYA-ARENARIA; GEORGES BANK; LONG-ISLAND; CLAM; BIVALVIA; GROWTH; MOLLUSCA; DYNAMICS; DILLWYN AB The Atlantic surfclam, Spisula solidissima (Dillwyn, 1817), is a dominant member of the benthic community on the continental shelf from Georges Bank to North Carolina, USA. This bivalve has supported a major fishery, primarily off New Jersey and the Delmarva Peninsula, since the 1960s. Early papers documented that these populations were at historical lows in the mid-1970s owing to commercial harvesting and a hypoxic event off New Jersey. It was also shown that major recruitment took place off New Jersey in 1976 and off the Delmarva Peninsula in 1977. Because the size frequencies of surfclams from federal surveys do not show distinct year classes, there has been uncertainty about the number of year classes in these populations throughout the 1980s and 1990s. The present study describes changes in population age- and size-structure from 1978 to 1997 in federal waters (greater than or equal to 5.5 km from shore) of the USA. Given the 30 to 35 year life span of S. solidissima, these populations could be composed of many year classes. Yet, these populations were composed of only two to three year classes in 1978. Through annual recruitment, the number of year classes increased over time, and populations off New Jersey and the Delmarva Peninsula contained at least 19 year classes in 1997. This major change in population structure over time was not evident from examination of available size-frequency data, and could only be inferred from data on age-composition. Throughout the 1980s and 1990s, the surfclam fishery was supported by multiple year classes. The mean and variance of recruitment to the New Jersey region, as indicated by the abundance of 4-year-olds over time, was greater than that off Delmarva, particularly between 1980 and 1986, The instantaneous rate of adult mortality, which includes the effect of harvesting, was approximately 0.26 yr(-1) in each region. C1 Natl Marine Fisheries Serv, Populat Dynam Branch, Woods Hole, MA 02543 USA. RP Weinberg, JR (reprint author), Natl Marine Fisheries Serv, Populat Dynam Branch, Woods Hole, MA 02543 USA. NR 52 TC 28 Z9 30 U1 1 U2 5 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 JUN PY 1999 VL 134 IS 1 BP 113 EP 125 DI 10.1007/s002270050530 PG 13 WC Marine & Freshwater Biology SC Marine & Freshwater Biology GA 210QZ UT WOS:000081117300012 ER PT J AU Wanninkhof, R Lewis, E Feely, RA Millero, FJ AF Wanninkhof, R Lewis, E Feely, RA Millero, FJ TI The optimal carbonate dissociation constants for determining surface water pCO(2) from alkalinity and total inorganic carbon SO MARINE CHEMISTRY LA English DT Article DE oceanography; carbon dioxide; dissociation; alkalinity ID EQUATORIAL PACIFIC; DIOXIDE SYSTEM; SEAWATER; ACID; CO2; CONSISTENCY; FUGACITY; OCEANS AB In many numerical ocean chemistry models, total dissolved inorganic carbon, DIC and total alkalinity, TA are transported between subsurface boxes. The partial pressure pCO(2) is subsequently calculated from TA and DIC in the surface box in order to account for air-sea exchange of carbon dioxide. The conversion is commonly performed by solving the thermodynamic relationships for equilibria between carbonate, bicarbonate, and aqueous CO2 using carbonate dissociation constants. Four independent determinations of the constants have been made for seawater in the past 50 years. These results have been corrected, refit, and combined by others creating a virtual cottage industry of laboratory and field verification, and cross-checks. Here, we show that, based on field observations in three ocean basins, the calculated surface water pCO(2) from TA and DIC corresponds best with the measured pCO(2) if the constants proposed by Mehrbach et al. [Mehrbach, C., Culberson, C.H., Hawley, J.E., Pytkowicz, R.M., 1973. Measurement of the apparent dissociation constants of carbonic acid in seawater at atmospheric pressure. Limnology and Oceanography 18, 897-907] as refit by Dickson and Millero [Dickson, A.G., Millero, F.J., 1987. A comparison of the equilibrium constants for the dissociation of carbonic acid in seawater media. Deep-Sea Res. 34, 1733-1743] are used. This suggests that the K-1/K-2 ratio of Mehrbach et al. for a pCO(2) range of 280-450 mu atm is correct but it does not necessarily imply that the absolute values of K-1 and K-2 are correct or that these constants work as well at higher pCO(2). An independent cross-check with pCO(2) measurements made at constant temperature (20 degrees C) is in agreement with these conclusions. The differences in calculated pCO(2) can be as great as 30 mu atm depending which constants are used. If the models are forced with a prescribed atmospheric pCO(2) they will end up having surface concentration of TA that are up to 20 mu eq kg(-1) too high or DIC concentration up to 20 mu mol kg(-1) too low if constants other than those of Mehrbach et al. are used. This makes comparisons between observation and models problematic. (C) 1999 Published by Elsevier Science B.V. C1 NOAA, Atlantic Oceanog & Meteorol Lab, Miami, FL 33149 USA. Brookhaven Natl Lab, Dept Appl Sci, Upton, NY 11973 USA. NOAA, Pacific Marine Environm Lab, Seattle, WA 98115 USA. Univ Miami, Rosenstiel Sch Marine & Atmospher Sci, Dept Marine & Atmospher Chem, Miami, FL 33149 USA. RP Wanninkhof, R (reprint author), NOAA, Atlantic Oceanog & Meteorol Lab, Miami, FL 33149 USA. NR 32 TC 63 Z9 67 U1 2 U2 15 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0304-4203 J9 MAR CHEM JI Mar. Chem. PD JUN PY 1999 VL 65 IS 3-4 BP 291 EP 301 DI 10.1016/S0304-4203(99)00021-3 PG 11 WC Chemistry, Multidisciplinary; Oceanography SC Chemistry; Oceanography GA 214ZW UT WOS:000081358300012 ER PT J AU Milliken, HO Farrington, M Carr, HA Lent, E AF Milliken, HO Farrington, M Carr, HA Lent, E TI Survival of Atlantic cod (Gadus morhua) in the northwest Atlantic longline fishery SO MARINE TECHNOLOGY SOCIETY JOURNAL LA English DT Article AB Longline fishing has often been promoted as a clean, low impact fishing method. Some longline fishermen and biologists have expressed concern that there is a high mortality rate for cod and haddock that pass through a dehooking device prior to release. The device, aptly called the "crucifier, " usually consists of two steel cylinders placed vertically on the gunwale of the vessel. During hauling, the gear passes through the opening between the cylinders while the fish, too large to pass through the narrow opening, is excluded. This process pulls the hook from the mouth of the fish and can inflict severe injuries such as torn and broken jaws. A study was conducted to determine the survival rate of sub-legal cod caught in the longline fishery using 11/0 circle hooks. The focus of the research was to assess the rate of mortality of sub-legal catch after the cod were placed in cages for 72 hours. The results of the study showed that there was high mortality (69%) associated with capture using the 11/0 circle hook when the fish were injured by the process of having the hooks removed from their mouths by the crucifier. Furthermore, sublegal cod that had wounds from the dehooking process and were under 39 cm were statistically more likely to die as compared to cod between. 38 and 49 mn. An ancillary set of observations on the predation by sea birds of released sublegal cod was included. Despite low numbers, the findings from these observations show that sea bird predation should be included when estimating the survival of fish caught by a longline. C1 MA Div Marine Fisheries, Pocasset, MA USA. New England Aquarium, Boston, MA USA. RP Milliken, HO (reprint author), NOAA, Natl Marine Fisheries Serv, Woods Hole, MA 02543 USA. NR 19 TC 19 Z9 20 U1 2 U2 3 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 1999 VL 33 IS 2 BP 19 EP 24 PG 6 WC Engineering, Ocean; Oceanography SC Engineering; Oceanography GA 225FY UT WOS:000081948800004 ER PT J AU Glass, CW Sarno, B Milliken, HO Morris, GD Carr, HA AF Glass, CW Sarno, B Milliken, HO Morris, GD Carr, HA TI Bycatch reduction in Massachusetts inshore squid (Loligo pealeii) trawl fisheries SO MARINE TECHNOLOGY SOCIETY JOURNAL LA English DT Article AB Small-mesh fishing for squid in Nantucket and Vineyard Sounds during the spring seasonal fishery result in high catch and discard of undersized flounder and scup, both important commercial and recreational fishery species. This study was designed to assess the extent of bycatch and discard in the Loligo pealeii squid inshore fishery and to describe and document the behavior patterns of squid and nontarget fish in relation to fishing gear. Bycatch rates vary spatially and temporally but over 30% by weight of total catch are discarded at sea. The main bycatch and discard species comprise flatfish (summer flounder Paralichthys dentatus and winter flounder Pseudopleuronectes americanus), scup (Stenotomus chrysops) and butterfish (Peprilus triacanthus). Videotape recordings and behavioral analysis of squid reactions have shown that squid display classical herding behavior and considerable swimming endurance in the forward part of the net. Loligo are shown to rise when dropping back towards the codend and in some cases to turn and rise on tiring. This behavior may be used to separate squid from the main bycatch species. Separator trawl test-trials have demonstrated that clear separation between squid and bycatch species can be achieved by simple gear modifications. C1 Manomet Ctr Conservat Sci, Manomet, MA USA. Natl Marine Fisheries Serv, Woods Hole, MA 02543 USA. Massachusetts Div Marine Fisheries, Pocasset, MA USA. RP Glass, CW (reprint author), Manomet Ctr Conservat Sci, Manomet, MA USA. NR 23 TC 11 Z9 11 U1 1 U2 6 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 1999 VL 33 IS 2 BP 35 EP 42 PG 8 WC Engineering, Ocean; Oceanography SC Engineering; Oceanography GA 225FY UT WOS:000081948800006 ER PT J AU Engaas, A Foster, D Hataway, BD Watson, JW Workman, I AF Engaas, A Foster, D Hataway, BD Watson, JW Workman, I TI The behavioral response of juvenile red snapper (Lutjanus campechanus) to shrimp trawls that utilize water flow modifications to induce escapement SO MARINE TECHNOLOGY SOCIETY JOURNAL LA English DT Article AB Clear differences in swimming ability between finfish and shrimp in trawls have been utilized in the Southeastern U.S shrimp fishery to reduce the bycatch of finfish The Jones/Davis device which has been mandated for use in the Gulf of Mexico shrimp fishery uses four windows to provide an escape path for fish while a funnel keeps the shrimp away from the windows, reduces water flow around the windows, and acts as a leading panel to guide the fish out of the trawl. Observations of fish behavior showed that finfish generally reacted to the slack waterflow created by the funnel by swimming towards the lowest water flow area. The escape rate of finfish such as juvenile red snapper (Lutjanus campechanus), however, was low and random during towing when no net surging and fish crowding occurred. The highest escape rates occurred during slow down prior to haulback, but were dependent on the haul back procedure. This may help explain the haul-to-haul variation in escapement documented for the Jones/Davis device. Modifications and techniques to improve escape rates during towing are discussed. C1 Marine Res Inst, Fish Capture Div, Bergen, Norway. US Dept Commerce, NOAA, SE Fisheries Ctr, Pascagoula, MS USA. RP Engaas, A (reprint author), Marine Res Inst, Fish Capture Div, Bergen, Norway. NR 22 TC 16 Z9 17 U1 0 U2 6 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 1999 VL 33 IS 2 BP 43 EP 50 PG 8 WC Engineering, Ocean; Oceanography SC Engineering; Oceanography GA 225FY UT WOS:000081948800007 ER PT J AU Watson, J Foster, D Nichols, S Shah, A Scott-Denton, E Nance, J AF Watson, J Foster, D Nichols, S Shah, A Scott-Denton, E Nance, J TI The development of bycatch reduction technology in the southeastern United States shrimp fishery SO MARINE TECHNOLOGY SOCIETY JOURNAL LA English DT Article AB Shrimp trawl bycatch is a significant source of fishery induced mortality for managed species including red snapper (Lutjanus campechanus Poey), Spanish mackerel (Scomberomorus maculatus Mitchell), and weakfish (Cynoscion regalis Baloch, Schneider) in the southeastern United States. These species have been overfished and are under both state and federal management plans which include regulations mandating reduction of shrimp trawl bycatch mortality. In 1990 the U.S. Congress passed amendments to the Magnuson Fishery Conservation and Management Act (16 U.S.C. 1854) which called for a research program that included the design and evaluation of approaches for reducing shrimp trawl bycatch mortality. A strategic planning initiative addressing finfish bycatch in the Gulf of Mexico and southeastern Atlantic shrimp fisheries was developed by the Gulf and South Atlantic Fisheries Foundation through funding and guidance provided by the National Marine Fisheries Service. A cooperative research plan was developed in 1992 which included the identification, development, and evaluation of gear options for reducing bycatch in the Gulf of Mexico and southeastern Atlantic shrimp fisheries. Between 1990 and 1996 one hundred and forty five bycatch reduction conceptual gear designs contributed by fishers, net shops, gear technicians, and biologists were evaluated. Sixteen of these designs were tested on cooperative commercial shrimp vessels by observers under the southeast regional cooperative bycatch program. Analyses of data from commercial vessel testing indicates that two bycatch reduction designs have potential to significantly reduce shrimp trawl bycatch for weakfish, and Spanish mackerel in the southeastern Atlantic and two designs have the potential to significantly reduce red snapper bycatch in the Gulf of Mexico. The fisheye and the extended funnel bycatch reduction devices have been mandated for use in the southeastern Atlantic shrimp fishery and the fisheye and Jones/Davis bycatch reduction devices have been mandated for use in the Gulf of Mexico shrimp trawl fishery. C1 US Dept Commerce, NOAA, SE Fisheries Sci Ctr, Mississippi Labs, Pascagoula, MS USA. Univ S Alabama, Dept Math & Stat, Mobile, AL 36688 USA. US Dept Commerce, NOAA, SE Fisheries Sci Ctr, Galveston Lab, Galveston, TX USA. RP Watson, J (reprint author), US Dept Commerce, NOAA, SE Fisheries Sci Ctr, Mississippi Labs, Pascagoula, MS USA. NR 12 TC 10 Z9 14 U1 2 U2 21 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 1999 VL 33 IS 2 BP 51 EP 56 PG 6 WC Engineering, Ocean; Oceanography SC Engineering; Oceanography GA 225FY UT WOS:000081948800008 ER PT J AU Rose, CS AF Rose, CS TI Initial tests of a flexible grate for size selection of trawl caught fish SO MARINE TECHNOLOGY SOCIETY JOURNAL LA English DT Article ID LIGHT AB The fish, size selection and handling features of a trawl-mounted flexible grate were tested. The grate was constructed of fiberglass rods and neoprene strips to be flexible enough to bend around a net reel, but rigid enough to maintain consistent, long, rectangular openings for fish size selection during trawling. A 244 cm x 140 cm grate, installed in the extension section of a bottom trawl, was tested for size selection of walleye pollock (Theragra chalcogramma) in the Baring Sea by means of a small mesh auxiliary net that collected escapees. A grate with 44 mm spacing had an L-50, the length at which 50% of the fish escaped, of 37 cm and a selection range estimated at 10 cm. Few fish longer than 44 cm escaped, corresponding to pollock with head widths equal to the 44 mm bar spacing. The grate was easily deployed and retrieved from a net reel, without any special gear handling procedures required. In-situ video observations using infrared illumination confirmed that the panel and collection net assumed their correct configurations and that escaping pollock passed easily through the grate. C1 NOAA, Natl Marine Fisheries Serv, Resource Assessment & Conservat Engn Div, Alaska Fisheries Sci Ctr, Seattle, WA 98115 USA. RP Rose, CS (reprint author), NOAA, Natl Marine Fisheries Serv, Resource Assessment & Conservat Engn Div, Alaska Fisheries Sci Ctr, Seattle, WA 98115 USA. NR 11 TC 2 Z9 5 U1 0 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 1999 VL 33 IS 2 BP 57 EP 60 PG 4 WC Engineering, Ocean; Oceanography SC Engineering; Oceanography GA 225FY UT WOS:000081948800009 ER PT J AU Rivera, KS Wohl, KD AF Rivera, KS Wohl, KD TI The FAO seabird initiative - International efforts to reduce seabird bycatch in the longline fisheries: What does that mean at home? An Alaskan perspective SO MARINE TECHNOLOGY SOCIETY JOURNAL LA English DT Editorial Material C1 Natl Marine Fisheries Serv, Protected Resources Div, Juneau, AK 99801 USA. US Fish & Wildlife Serv, Off Migratory Bird Management, Anchorage, AK USA. RP Rivera, KS (reprint author), Natl Marine Fisheries Serv, Protected Resources Div, Juneau, AK 99801 USA. NR 6 TC 1 Z9 1 U1 0 U2 0 PU MARINE TECHNOLOGY SOC INC PI WASHINGTON PA C/O I CLAYION MATTHEWS, 1828 L ST, NW, 9TH FL, WASHINGTON, DC 20036 USA SN 0025-3324 J9 MAR TECHNOL SOC J JI Mar. Technol. Soc. J. PD SUM PY 1999 VL 33 IS 2 BP 85 EP 87 PG 3 WC Engineering, Ocean; Oceanography SC Engineering; Oceanography GA 225FY UT WOS:000081948800013 ER PT J AU Swartzendruber, LJ AF Swartzendruber, LJ TI Comments on the calibration and use of the NIST test ring (SRM 1853) SO MATERIALS EVALUATION LA English DT Editorial Material DE calibration; ferromagnetics; gaussmeter; leakage field; magnetic particle test rings; Standard Reference Material AB The technique used at NIST to calibrate the Standard Reference Material (SRM) 1853 test rings is described. Details of the leakage fields from these rings are given and some suggestions made from their use. C1 NIST, Gaithersburg, MD 20899 USA. RP Swartzendruber, LJ (reprint author), NIST, Gaithersburg, MD 20899 USA. NR 4 TC 2 Z9 2 U1 0 U2 0 PU AMER SOC NON-DESTRUCTIVE TEST PI COLUMBUS PA 1711 ARLINGATE LANE PO BOX 28518, COLUMBUS, OH 43228-0518 USA SN 0025-5327 J9 MATER EVAL JI Mater. Eval. PD JUN PY 1999 VL 57 IS 6 BP 594 EP 596 PG 3 WC Materials Science, Characterization & Testing SC Materials Science GA 208HK UT WOS:000080984800005 ER PT J AU Han, WH Horkay, F McKenna, GB AF Han, WH Horkay, F McKenna, GB TI Mechanical and swelling behaviors of rubber: A comparison of some molecular models with experiment SO MATHEMATICS AND MECHANICS OF SOLIDS LA English DT Article ID ENTANGLEMENT MODELS; LOCALIZATION MODEL; EXPERIMENTAL TESTS; POLYMER NETWORKS; ELASTICITY; CONSTRAINTS; STRAIN; STRESS AB A review is given of several current network models (constrained chain model, localization model, liquidlike model, and eight-chain model) that have been developed to explain nonideal rubbery behavior. The stress-strain relationships for both dry and swollen networks are discussed. It is shown that the constrained chain model of Flory, Erman, and Monnerie provides the best description of the considered models for the stress-strain response of both the dry state and swollen state properties of cross-linked rubber networks. The localization model of Gaylord and Douglas fits the dry-state stress-strain data very well, but the predictions of the mechanical response in the swollen state are not as good as those obtained with the constrained chain model. The liquidlike model of DiMarzio yields reasonable description of extension behavior, but it does not explain the observed modest decrease of the elastic modulus (reduced stress) with increasing compression; nor does the liquidlike model predict the decreasing modulus with increasing swelling correctly. The eight-chain model of Arruda and Boyce puts forward a stress-strain relation that includes the finite extensibility of the network chains. It is shown that at moderate deformation ratios, the eight-chain model does not provide even qualitative agreement with the experimental stress-strain data for both the dry and swollen states. C1 NIST, Div Polymers, Gaithersburg, MD 20899 USA. RP McKenna, GB (reprint author), NIST, Div Polymers, Gaithersburg, MD 20899 USA. RI McKenna, Gregory/O-1134-2013 OI McKenna, Gregory/0000-0002-5676-9930 NR 48 TC 52 Z9 52 U1 2 U2 10 PU SAGE PUBLICATIONS INC PI THOUSAND OAKS PA 2455 TELLER RD, THOUSAND OAKS, CA 91320 USA SN 1081-2865 J9 MATH MECH SOLIDS JI Math. Mech. Solids PD JUN PY 1999 VL 4 IS 2 BP 139 EP 167 DI 10.1177/108128659900400201 PG 29 WC Materials Science, Multidisciplinary; Mathematics, Interdisciplinary Applications; Mechanics SC Materials Science; Mathematics; Mechanics GA 199JC UT WOS:000080476600001 ER PT J AU Schwarz, JP Robertson, DS Niebauer, TM Faller, JE AF Schwarz, JP Robertson, DS Niebauer, TM Faller, JE TI A new determination of the Newtonian constant of gravity using the free fall method SO MEASUREMENT SCIENCE AND TECHNOLOGY LA English DT Article; Proceedings Paper CT Conference on the Gravitational Constant - Theory and Experiment 200 Years After Cavendish CY NOV 23-24, 1998 CL INST PHYS, PORTLAND PLACE, ENGLAND HO INST PHYS DE gravity; gravimeter; G; Newtonian constant of gravity ID GRAVITATIONAL CONSTANT; ABSOLUTE AB We report on a recent determination of the Newtonian constant of gravity, G, using a new 'free fall' method. This method uses a freely falling test object to sense the gravitational field of a ring-shaped mass placed alternately above and below the drop region. The measurement of the changes in acceleration of the test object allow determination of G. Because the test mass is unsupported, systematic errors associated with the free fall method are significantly different from those of the traditional torsion experiments that constitute the great majority of G measurements. This characteristic makes this method potentially valuable in the context of today's uncertainty about the value of G. The raw data have been examined in a variety of ways. We describe our methods which allow us to extract, besides G, information about various experimental parameters and possible systematic errors. A number of sources of systematic errors have been investigated, including magnetic and vibratory signals arising from the dropping action of our apparatus. We outline the steps we have taken to ascertain the magnitude of errors introduced by these effects. Using the free fall method, we have completed a determination of G, obtaining a result of G = (6.6873 +/- 0.0094) x 10(-11) m(3) kg(-1) s(2). C1 Univ Colorado, Boulder, CO 80309 USA. NIST, Boulder, CO 80309 USA. NOAA, Natl Geodet Survey, Boulder, CO 80309 USA. Univ Colorado, Cires, Boulder, CO 80309 USA. Colorado Sch Mines, Dept Geophys, Golden, CO 80401 USA. RP Univ Colorado, Boulder, CO 80309 USA. RI schwarz, joshua/G-4556-2013 OI schwarz, joshua/0000-0002-9123-2223 NR 13 TC 18 Z9 20 U1 1 U2 5 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0957-0233 EI 1361-6501 J9 MEAS SCI TECHNOL JI Meas. Sci. Technol. PD JUN PY 1999 VL 10 IS 6 BP 478 EP 486 DI 10.1088/0957-0233/10/6/311 PG 9 WC Engineering, Multidisciplinary; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA 205AY UT WOS:000080800200013 ER PT J AU Chadwick, MB Barschall, HH Caswell, RS DeLuca, PM Hale, GM Jones, DTL MacFarlane, RE Meulders, JP Schuhmacher, H Schrewe, UJ Wambersie, A Young, PG AF Chadwick, MB Barschall, HH Caswell, RS DeLuca, PM Hale, GM Jones, DTL MacFarlane, RE Meulders, JP Schuhmacher, H Schrewe, UJ Wambersie, A Young, PG TI A consistent set of neutron kerma coefficients from thermal to 150 MeV for biologically important materials SO MEDICAL PHYSICS LA English DT Article DE kerma coefficients; cross sections; nuclear data; neutron dosimetry; therapy ID DIFFERENTIAL INCLUSIVE HYDROGEN; SCATTERING CROSS-SECTIONS; PARTICLE PRODUCTION; ENERGY-RANGE; NUCLEAR-DATA; ANGULAR-DISTRIBUTIONS; HELIUM SPECTRA; LIGHT-NUCLEI; CARBON; THERAPY AB Neutron cross sections for nonelastic and elastic reactions on a range of elements have been evaluated for incident energies up to 150 MeV. These cross sections agree well with experimental cross section data far charged-particle production as well as neutron and photon production. Therefore they can be used to determine kerma coefficients for calculations of energy deposition by neutrons in matter. Methods used to evaluate the neutron cross sections above 20 MeV, using nuclear model calculations and experimental data, are described. Below 20 MeV, the evaluated cross sections from the ENDF/B-VI library are adopted. Comparisons are shown between the evaluated charged-particle production cross sections and measured data. Kerma coefficients are derived from the neutron cross sections, for major isotopes of H, C, N, O, Al, Si, P, Ca, Fe, Cu, W, Pb, and for ICRU-muscle, A-150 tissue-equivalent plastic, and other compounds important for treatment planning and dosimetry. Numerous comparisons are made between our kerma coefficients and experimental kerma coefficient data, to validate our results, and agreement is found to be good. An important quantity in neutron dosimetry is the kerma coefficient ratio of ICRU-muscle to A-150 plastic. When this ratio is calculated from our kerma coefficient data, and averaged over the neutron energy spectra for higher-energy clinical therapy beams [three p(68)+ Be beams, and a d(48.5) + Be beam], a value of 0.94+-0.03 is obtained. Kerma ratios for water to A-150 plastic, and carbon to oxygen, are also compared with measurements where available. (C) 1999 American Association of Physicists in Medicine. C1 Univ Calif Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Univ Wisconsin, Dept Med Phys, Madison, WI 53706 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Natl Accelerator Ctr, Cape Town, South Africa. Catholic Univ Louvain, B-3000 Louvain, Belgium. Phys Tech Bundesanstalt, D-3300 Braunschweig, Germany. RP Chadwick, MB (reprint author), Univ Calif Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. NR 90 TC 59 Z9 61 U1 1 U2 4 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0094-2405 J9 MED PHYS JI Med. Phys. PD JUN PY 1999 VL 26 IS 6 BP 974 EP 991 DI 10.1118/1.598601 PG 18 WC Radiology, Nuclear Medicine & Medical Imaging SC Radiology, Nuclear Medicine & Medical Imaging GA 207WM UT WOS:000080958800016 PM 10436900 ER PT J AU Ford, MJ Thornton, PJ Park, LK AF Ford, MJ Thornton, PJ Park, LK TI Natural selection promotes divergence of transferrin among salmonid species SO MOLECULAR ECOLOGY LA English DT Article DE evolution; neutral theory; Oncorhynchus; positive selection; salmon; transferrin ID POSITIVE SELECTION; SYNONYMOUS SUBSTITUTION; ONCORHYNCHUS-KISUTCH; ATLANTIC SALMON; SILENT SITES; IRON; DROSOPHILA; EVOLUTION; POLYMORPHISM; CLONING AB Transferrin is an iron-binding protein that plays an important role in iron metabolism and resistance to bacterial infection in a variety of organisms. A comparison of transferrin coding sequences from four salmonid species shows that the rate of evolution at nonsynonymous sites is significantly higher than the rate at synonymous sites, suggesting that positive natural selection for new alleles has played an important role in the evolution of transferrin in some salmon species. We hypothesize that the selective agent driving rapid divergence is interactions between host transferrin and the iron-scavenging proteins of pathogenic bacteria. C1 NOAA, Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, Conservat Biol Div, Seattle, WA 98112 USA. RP Ford, MJ (reprint author), NOAA, 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 37 TC 21 Z9 21 U1 1 U2 3 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 JUN PY 1999 VL 8 IS 6 BP 1055 EP 1061 DI 10.1046/j.1365-294x.1999.00651.x PG 7 WC Biochemistry & Molecular Biology; Ecology; Evolutionary Biology SC Biochemistry & Molecular Biology; Environmental Sciences & Ecology; Evolutionary Biology GA 219UE UT WOS:000081624800014 PM 10434423 ER PT J AU Dodge, P Burpee, RW Marks, FD AF Dodge, P Burpee, RW Marks, FD TI The kinematic structure of a hurricane with sea level pressure less than 900 mb SO MONTHLY WEATHER REVIEW LA English DT Article ID DOPPLER RADAR OBSERVATIONS; CONVECTIVE-SCALE CHARACTERISTICS; SECONDARY WIND MAXIMA; INNER CORE STRUCTURE; TROPICAL CYCLONES; MATURE HURRICANES; BOUNDARY-LAYER; ALLEN 1980; EVOLUTION; AIRCRAFT AB A National Oceanic and Atmospheric Administration aircraft recorded the first Doppler radar data in a tropical cyclone with a minimum sea level pressure (MSLP) <900 mb during a reconnaissance mission in Hurricane Gilbert on 14 September 1988, when its MSLP was similar to 895 mb. A previous mission had found an MSLP of 888 mb, making Gilbert the most intense tropical cyclone yet observed in the Atlantic basin. Radar reflectivity identified the hurricane eye, inner and outer eyewalls, a stratiform region between the eyewalls, and an area outside the outer eyewall that contained a few rainbands but that had mostly stratiform rain. Pseudo-dual Doppler analyses depict the three-dimensional kinematic structure of the inner eyewall and a portion of the outer eyewall. The vertical profiles of tangential wind and reflectivity maxima in the inner eyewall are more erect than in weaker storms, and winds >50 m s(-1) extended to 12 km, higher than has been reported in previous hurricanes. The inner eyewall contained weak inflow throughout most of its depth. In contrast, the portion of the outer eyewall described here had shallow inflow and a broad region of outflow. The stratiform region between the two eyewalls had lower reflectivities and was the only region where the vertically incident Doppler radar data seemed to show downward motion below the freezing level. Gilbert's structure is compared with other intense Atlantic and eastern North Pacific hurricanes with MSLP >900 mb. Storms with lower MSLP have higher wind speeds in both inner and outer eyewalls, and wind speeds >50 m s(-1) extend higher in storms with lower MSLP. Hurricanes Gilbert and Gloria (1985), the strongest Atlantic hurricanes yet analyzed by the Hurricane Research Division, had different outer eyewall structures. Gloria's outer eyewall had a deep region of inflow, while Gilbert's inflow layer was shallow. This may explain differences in the subsequent evolution of the two storms. C1 NOAA, Atlantic Oceanog & Meteorol Lab, Hurricane Res Div, Miami, FL 33149 USA. RP Dodge, P (reprint author), NOAA, Atlantic Oceanog & Meteorol Lab, Hurricane Res Div, 4301 Rickenbacker Causeway, Miami, FL 33149 USA. RI Marks, Frank/A-5733-2011; dodge, peter/A-9808-2017 OI Marks, Frank/0000-0003-0371-5514; NR 47 TC 43 Z9 48 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 JUN PY 1999 VL 127 IS 6 BP 987 EP 1004 DI 10.1175/1520-0493(1999)127<0987:TKSOAH>2.0.CO;2 PN 1 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 207AR UT WOS:000080913600004 ER PT J AU Schultz, DM Steenburgh, WJ AF Schultz, DM Steenburgh, WJ TI The formation of a forward-tilting cold front with multiple cloud bands during Superstorm 1993 SO MONTHLY WEATHER REVIEW LA English DT Article ID MID-ATLANTIC COAST; UNITED-STATES; MICROSCALE STRUCTURE; MIDLATITUDE CYCLONE; PREFRONTAL TROUGHS; SOUTHERN AUSTRALIA; MESOSCALE MODELS; EASTERN PACIFIC; ROCKY-MOUNTAINS; EVOLUTION AB A mesoscale-model simulation is used to examine the evolution of the cold front and accompanying cloud bands in eastern Mexico associated with Superstorm 1993 (12-14 March). The simulated cold front differed in structure and evolution from a classical cold front, in agreement with evidence from observations and European Centre for Medium-Range Weather Forecasts analyses. The surface cold front, as defined by the leading edge of strong northerlies and cold advection, initially possessed a rearward till with height over southern Texas. Within 6 h, the leading edge of the front moved equatorward and developed a large-scale forward tilt of greater than 200 km in the horizontal from the surface to 700 hPa. This forward tilt occurred as a mid- to upper-tropospheric baroclinic zone arrived from over the Sierra Madre, descended into eastern Mexico, and interacted with the surface cold front. Embedded within this large-scale forward tilt was a locally enhanced horizontal potential temperature gradient that also tilted forward similar to 100 km from the surface to 850 hPa. Tilting frontogenesis associated with ascent at the leading edge of the surface front was responsible for the smaller-scale forward-tilting structure. This surface-based ascent is believed to have caused the primary cloud band observed from satellite imagery that is coincident with the leading edge of the front, whereas a second region of ascent, elevated at the leading edge of the mid- to upper-tropospheric baroclinic zone, is believed to have caused the prefrontal cloud band revealed by satellite imagery. Subsidence behind the forward-tilting cold-frontal structure at and above 850 hPa (and concomitant divergence underneath) resulted in frontolysis of the surface front, and eventually the dissipation of the primary cloud band, leading to the dominance of the prefrontal cloud band. Finally, the Superstorm 1993 cold front is compared and contrasted to nonclassical cold-frontal structures found in the literature and a general context for frontal interaction is discussed. C1 NOAA, Natl Severe Storms Lab, Norman, OK 73069 USA. Univ Utah, Dept Meteorol, Salt Lake City, UT 84112 USA. NOAA, Cooperat Inst Reg Predict, Salt Lake City, UT USA. SUNY Albany, Albany, NY 12222 USA. RP Schultz, DM (reprint author), NOAA, Natl Severe Storms Lab, 1313 Halley Circle, Norman, OK 73069 USA. RI Schultz, David M./A-3091-2010 OI Schultz, David M./0000-0003-1558-6975 NR 63 TC 14 Z9 15 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 JUN PY 1999 VL 127 IS 6 BP 1108 EP 1124 DI 10.1175/1520-0493(1999)127<1108:TFOAFT>2.0.CO;2 PN 1 PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 207AR UT WOS:000080913600012 ER PT J AU Marzban, C Lakshmanan, V AF Marzban, C Lakshmanan, V TI On the uniqueness of Gandin and Murphy's equitable performance measures SO MONTHLY WEATHER REVIEW LA English DT Article AB Gandin and Murphy (GM) have shown that if a skill score is linear in the scoring matrix, and if the scoring matrix is symmetric, then in the two-event case there exists a unique, "equitable" skill score, namely, the True Skill Score (or Kuipers's performance index). As such, this measure is treated as preferable to other measures because of its equitability. However, in most practical situations the scoring matrix is not symmetric due to the unequal costs associated with false alarms and misses. As a result, GM's considerations must be reexamined without the assumption of a symmetric scoring matrix. In this note, it will be proven that if the scoring matrix is nonsymmetric, then there does not exist a unique performance measure, linear in the scoring matrix, that would satisfy any constraints of equitability. In short, there does not exist a unique, equitable skill score for two-category events that have unequal costs associated with a miss and a false alarm. C1 Natl Severe Storms Lab, Norman, OK 73069 USA. Cooperat Inst Mesoscale & Meteorol Studies, Norman, OK USA. Univ Oklahoma, Dept Phys, Norman, OK 73019 USA. RP Marzban, C (reprint author), Natl Severe Storms Lab, 1313 Halley Circle, Norman, OK 73069 USA. NR 6 TC 6 Z9 6 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 1999 VL 127 IS 6 BP 1134 EP 1136 DI 10.1175/1520-0493(1999)127<1134:OTUOGA>2.0.CO;2 PN 1 PG 3 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 207AR UT WOS:000080913600014 ER PT J AU Colle, BA Mass, CF Shull, BF AF Colle, BA Mass, CF Shull, BF TI An observational and numerical study of a cold front interacting with the Olympic Mountains during COAST IOP5 SO MONTHLY WEATHER REVIEW LA English DT Article ID MID-LATITUDE CYCLONES; STRATIFIED ROTATING ATMOSPHERE; WESTERN UNITED-STATES; MICROSCALE STRUCTURE; EXTRATROPICAL CYCLONES; MESOSCALE OROGRAPHY; PACIFIC-NORTHWEST; ROCKY-MOUNTAINS; COMPLEX TERRAIN; RAINBANDS AB This paper documents the three-dimensional how and precipitation structures associated with a weak cold front interacting with the Olympic Mountains and the subsequent development of a Puget Sound convergence zone. This study utilizes data collected during COAST IOP5 (the fifth intensive observing period of the Coastal Observation and Simulation with Topography field experiment) that took place on 11-12 December 1993. One of the most important data sources was a NOAA P-3 aircraft, which provided flight-level data, radar reflectivity, and Doppler winds as it circumnavigated the Olympics. Initially, frontal passage along the western foothills of the Olympics was accompanied by a 2 degrees-3 degrees C temperature drop, a rapid wind shift to northwesterlies, and an intense line of precipitation (35-45 dBZ); however, the wind shift and associated precipitation structures attenuated when the front began to ascend the windward slopes of the Olympics. Surface and P-3 observations document the deformation of the front around the Olympics. The front accelerated and became more intense and shallow to the northeast of the Olympics where it encountered prefrontal downslope warming and strong southerlies. This portion of the front and the associated precipitation band moved southward toward central Puget Sound and eventually became stationary to the east of the Olympics, where a Puget Sound convergence zone developed and subsequently dissipated after a few hours. This case was simulated down to 3-km horizontal resolution using the Pennsylvania State University-National Center for Atmospheric Research Mesoscale Model (MM5). Frontogenesis calculations using the model data suggest that prefrontal how splitting around the Olympics intensified the front by enhanced stretching deformation as it approached the barrier. A simulation with half-height Olympics showed that reduced flow splitting resulted in a weaker front approaching the windward foothills. As observed by P-3 observations and in accordance with previous theoretical studies, frontolysis occurred as the modeled front ascended the windward slope. Sensitivity experiments showed that diabatic effects were important in maintaining the front as it rounded the north side of the Olympics and pushed southward toward central Puget Sound. C1 Univ Washington, Dept Atmospher Sci, Seattle, WA 98195 USA. Univ Washington, NOAA, Natl Severe Storms Lab, Seattle, WA 98195 USA. RP Univ Washington, Dept Atmospher Sci, Box 351640, Seattle, WA 98195 USA. EM cliff@atmos.washington.edu NR 59 TC 25 Z9 25 U1 1 U2 4 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 JUN PY 1999 VL 127 IS 6 BP 1310 EP 1334 DI 10.1175/1520-0493(1999)127<1310:AOANSO>2.0.CO;2 PN 2 PG 25 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 207AU UT WOS:000080913800010 ER PT J AU Long, CS AF Long, CS TI Estimating ultraviolet erythemal dosage amounts for various time periods using the UV index. SO PHOTOCHEMISTRY AND PHOTOBIOLOGY LA English DT Meeting Abstract C1 Natl Weather Serv, Climate Predict Ctr, Camp Springs, MD 20746 USA. NR 0 TC 0 Z9 0 U1 2 U2 2 PU AMER SOC PHOTOBIOLOGY PI AUGUSTA PA BIOTECH PARK, 1021 15TH ST, SUITE 9, AUGUSTA, GA 30901-3158 USA SN 0031-8655 J9 PHOTOCHEM PHOTOBIOL JI Photochem. Photobiol. PD JUN PY 1999 VL 69 SI SI BP 79S EP 79S PG 1 WC Biochemistry & Molecular Biology; Biophysics SC Biochemistry & Molecular Biology; Biophysics GA 220KB UT WOS:000081663200237 ER PT J AU Majkrzak, CF Berk, NF AF Majkrzak, CF Berk, NF TI Inverting neutron reflectivity from layered film structures using polarized beams SO PHYSICA B-CONDENSED MATTER LA English DT Article; Proceedings Paper CT 2nd Workshop on Polarised Neutrons for Condensed Matter Investigations (PNCMI'98) CY SEP 21-23, 1998 CL INST LAUE LANGEVIN, CHADWICK AMPHITHEATER, GRENOBLE, FRANCE SP CEN Grenoble, Inst Laue Langevin, CNRS HO INST LAUE LANGEVIN, CHADWICK AMPHITHEATER DE neutron reflectometry; phase; inversion; polarized neutron scattering ID PHASE DETERMINATION; INVERSE PROBLEM; REFLECTOMETRY AB It has recently been discovered that the phase of neutrons specularly reflected from a film structure can be determined exactly, even in the dynamical scattering region at small wave vector transfer, by using polarized beams and a buried magnetic reference layer. This is possible for both magnetic and nonmagnetic material films of interest. Given the reflection amplitude as a function of wave vector transfer, the scattering potential can be uniquely obtained by direct inversion, without resort to fitting. A review of some of the theory is presented, and new experimental results are reported. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 NIST, Ctr Neutron Res, Gaithersburg, MD 20899 USA. RP Berk, NF (reprint author), Reactor E151, Gaithersburg, MD 20899 USA. EM nberk@nist.gov NR 17 TC 15 Z9 16 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 1999 VL 267 BP 168 EP 174 DI 10.1016/S0921-4526(99)00055-1 PG 7 WC Physics, Condensed Matter SC Physics GA 194AZ UT WOS:000080171100030 ER PT J AU Siebrecht, R Schreyer, A Schmitte, T Schmidt, W Zabel, H AF Siebrecht, R Schreyer, A Schmitte, T Schmidt, W Zabel, H TI Investigation of magnetic coupling phenomena in Fe1-xCrx/Cr-superlattices with spin-polarized neutrons SO PHYSICA B-CONDENSED MATTER LA English DT Article; Proceedings Paper CT 2nd Workshop on Polarised Neutrons for Condensed Matter Investigations (PNCMI'98) CY SEP 21-23, 1998 CL INST LAUE LANGEVIN, CHADWICK AMPHITHEATER, GRENOBLE, FRANCE SP CEN Grenoble, Inst Laue Langevin, CNRS HO INST LAUE LANGEVIN, CHADWICK AMPHITHEATER DE magnetic exchange coupling; Curie temperature; Neel temperature; neutron reflectivity ID DENSITY-WAVE ANTIFERROMAGNETISM; FE/CR(001) SUPERLATTICES; CR INTERLAYERS; FILMS AB We present the results of temperature dependent measurements of magnetically coupled Fe1-xCrx/Cr-superlattices. These results are supplementary to the ones known for non-collinearly coupled Fe/Cr-superlattices. By systematically varying the Cr concentration x we cover a wide range of the Fe1-xCrx-phase diagram. As an experimental technique spin-polarized neutron reflectivity with spin analysis and high-angle neutron scattering proves to be ideal for this work. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 Inst Max Von Laue Paul Langevin, F-38042 Grenoble, France. Ruhr Univ Bochum, Inst Festkorperphys, D-44780 Bochum, Germany. Natl Inst Stand & Technol, Ctr Neutron Res, Gaithersburg, MD 20899 USA. RP Siebrecht, R (reprint author), Inst Max Von Laue Paul Langevin, BP 156X, F-38042 Grenoble, France. EM siebrech@ill.fr RI Zabel, Hartmut/C-1994-2009 NR 19 TC 1 Z9 1 U1 0 U2 1 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 1999 VL 267 BP 207 EP 210 DI 10.1016/S0921-4526(99)00068-X PG 4 WC Physics, Condensed Matter SC Physics GA 194AZ UT WOS:000080171100038 ER PT J AU Lee, SH Majkrzak, CF AF Lee, SH Majkrzak, CF TI A new technique for polarized neutron diffraction SO PHYSICA B-CONDENSED MATTER LA English DT Article; Proceedings Paper CT 2nd Workshop on Polarised Neutrons for Condensed Matter Investigations (PNCMI'98) CY SEP 21-23, 1998 CL INST LAUE LANGEVIN, CHADWICK AMPHITHEATER, GRENOBLE, FRANCE SP CEN Grenoble, Inst Laue Langevin, CNRS HO INST LAUE LANGEVIN, CHADWICK AMPHITHEATER DE polarized neutron diffraction; area-sensitive detector AB We have developed a new technique for polarized neutron diffraction utilizing a two-dimensional, area-sensitive detector. An area-sensitive detector, used in conjunction with a transmission polarizer in the scattered beam, allows us to simultaneously measure non-spin-flip (NSF) and spin-flip (SF) scattering processes and therefore increases the data collection rate by a factor of two. (C) 1999 Elsevier Science B.V. All rights reserved. C1 NIST, Ctr Neutron Res, Gaithersburg, MD 20899 USA. Univ Maryland, College Pk, MD 20742 USA. RP Lee, SH (reprint author), NIST, Ctr Neutron Res, Gaithersburg, MD 20899 USA. EM shl@rrdjazz.nist.gov NR 8 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 1999 VL 267 BP 341 EP 343 DI 10.1016/S0921-4526(99)00040-X PG 3 WC Physics, Condensed Matter SC Physics GA 194AZ UT WOS:000080171100063 ER PT J AU Kitching, J Hollberg, L AF Kitching, J Hollberg, L TI Interference-induced optical gain without population inversion in cold, trapped atoms SO PHYSICAL REVIEW A LA English DT Article ID ELECTROMAGNETICALLY INDUCED TRANSPARENCY; LIGHT AMPLIFICATION; QUANTUM INTERFERENCE; LASER OSCILLATION; 3-LEVEL SYSTEM; RUBIDIUM ATOMS; SODIUM; COHERENCE; LINE; TRANSITIONS AB Continuous-wave (cw) optical gain of 1.3x10(-2) cm(-1) is obtained on a probe transition in a driven, three-level, V-type atomic system: The atoms exhibit no population inversion between the probe excited state and the dressed ground stares of the combined atom-drive Hamiltonian. This gain without population inversion is interpreted as direct evidence of quantum interference, arising from coherences established in the atom by the applied optical fields. Agreement with a simple four-level theoretical model is excellent. [S1050-2947(99)01306-2]. C1 Natl Inst Stand & Technol, Div Time & Frequency, Boulder, CO 80303 USA. JILA, Boulder, CO USA. Univ Colorado, Boulder, CO 80309 USA. RP Natl Inst Stand & Technol, Div Time & Frequency, 325 Broadway,MS 847-10, Boulder, CO 80303 USA. NR 42 TC 74 Z9 75 U1 0 U2 5 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 JUN PY 1999 VL 59 IS 6 BP 4685 EP 4689 DI 10.1103/PhysRevA.59.4685 PG 5 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 204RH UT WOS:000080777600073 ER PT J AU Paul, BD Dowell, ML Gallagher, A Cooper, J AF Paul, BD Dowell, ML Gallagher, A Cooper, J TI Observation of conical emission from a single self-trapped beam SO PHYSICAL REVIEW A LA English DT Article ID FOCUSED LIGHT-PROPAGATION; FULLY SATURABLE MEDIUM; PUMPED 2-LEVEL ATOMS; CONE EMISSION; PULSE-PROPAGATION; BARIUM VAPOR; SODIUM VAPOR; DYE-LASER; RADIATION; MODE AB We report observations of conical emission from a pulsed laser beam with incident laser power, detuning, and beam diameter matched to a range of single, steady-state filaments. The beam thus propagates with nearly constant diameter through 5 cm of strontium (Sr) vapor. Emission angles (theta) are imaged as the height on the input slit of a 1.5 m spectrometer; a charge-coupled device camera in the spectrometer exit plane measures energy as a function of theta and frequency. Data are reported versus laser-pulse energy, diameter and detuning, and the collisional dephasing rate. Spectrally broad, red-detuned cones are observed, but only when the laser beam is predominately self-trapped. As previously observed in experiments where the beam breaks up into multiple filaments, forward emission at the blue-detuned Rabi sideband is much weaker than at the red (cone) sideband. The cone angle is largely independent of the phase velocity of the self-trapped laser beam, which varies from the vapor to the vacuum speed. The efficiency of the cone emission shows incomplete saturation, as well as strong dependence on self-trapped filament parameters. C1 Natl Inst Stand & Technol, Joint Inst Lab Astrophys, Dept Phys, Boulder, CO 80309 USA. Univ Colorado, Boulder, CO 80309 USA. RP Paul, BD (reprint author), Natl Inst Stand & Technol, Joint Inst Lab Astrophys, Dept Phys, Boulder, CO 80309 USA. NR 42 TC 15 Z9 15 U1 0 U2 1 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD JUN PY 1999 VL 59 IS 6 BP 4784 EP 4796 DI 10.1103/PhysRevA.59.4784 PG 13 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 204RH UT WOS:000080777600086 ER PT J AU Machholm, M Julienne, PS Suominen, KA AF Machholm, M Julienne, PS Suominen, KA TI Collisions of cold magnesium atoms in a weak laser field SO PHYSICAL REVIEW A LA English DT Article ID COOLED ATOMS; SPECTROSCOPY AB We use quantum scattering methods to calculate the light-induced collisional loss of laser-cooled and trapped magnesium atoms for detunings up to 30 atomic Linewidths to the red of the S-1(0)-P-1(1) cooling transition. Magnesium has no hyperfine structure to complicate the theoretical studies. We evaluate both the radiative and nonradiative mechanisms of trap loss. The radiative escape mechanism via allowed (1)Sigma(u), excitation is dominant for more than about one atomic linewidth detuning. Molecular vibrational structure due to photoassociative transitions to bound states begins to appear beyond about ten linewidths detuning. [S1050-2947(99)50306-5]. C1 Aarhus Univ, Dept Chem, DK-8000 Aarhus C, Denmark. Univ Copenhagen, Orsted Lab, NBIfAFG, DK-2100 Copenhagen, Denmark. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Helsinki Inst Phys, FIN-00014 Helsinki, Finland. RP Machholm, M (reprint author), 23 Holland Hill,B1-11 Holland Peak, Singapore 278739, Singapore. RI Suominen, Kalle-Antti/H-9076-2012; Julienne, Paul/E-9378-2012 OI Suominen, Kalle-Antti/0000-0002-1091-2893; Julienne, Paul/0000-0002-5494-1442 NR 19 TC 16 Z9 16 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 JUN PY 1999 VL 59 IS 6 BP R4113 EP R4116 DI 10.1103/PhysRevA.59.R4113 PG 4 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 204RH UT WOS:000080777600002 ER PT J AU Anderson, CR Andersen, KH Bossy, J Stirling, WG Dimeo, RM Sokol, PE Cook, JC Brown, DW AF Anderson, CR Andersen, KH Bossy, J Stirling, WG Dimeo, RM Sokol, PE Cook, JC Brown, DW TI High-resolution neutron-scattering study of the roton in confined superfluid He-4 SO PHYSICAL REVIEW B LA English DT Article ID COLLECTIVE EXCITATIONS; AEROGEL AB We report high-resolution neutron inelastic-scattering measurements of the roton energy and linewidth of superfluid He-4 confined in 95% porosity aerogel glass far temperatures 0.082.0.CO;2 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 211PR UT WOS:000081169800003 ER PT J AU Hall, T Brooks, HE Doswell, CA AF Hall, T Brooks, HE Doswell, CA TI Precipitation forecasting using a neural network SO WEATHER AND FORECASTING LA English DT Article ID ATTRIBUTES; PREDICTION; SKILL; EVENT AB A neural network, using input from the Era Model and upper air soundings, has been developed for the probability of precipitation (PoP) and quantitative precipitation forecast (QPF) for the Dallas-Fort Worth, Texas, area. Forecasts from two years were verified against a network of 36 rain gauges. The resulting forecasts were remarkably sharp, with over 70% of the PoP forecasts being less than 5% or greater than 95%. Of the 436 days with forecasts of less than 5% PoP, no rain occurred on 435 days. On the 111 days with forecasts of greater than 95% PoP, rain always occurred. The linear correlation between the forecast and observed precipitation amount was 0.95. Equitable threat scores for threshold precipitation amounts from 0.05 in. (similar to 1 mm) to 1 in. (similar to 25 mm) are 0.63 or higher, with maximum values over 0.86. Combining the PoP and QPF products indicates that for very high PoPs, the correlation between the QPF and observations is higher than for lower pops. In addition, 61 of the 70 observed rains of at least 0.5 in. (12.7 mm) are associated with PoPs greater than 85%. As a result, the system indicates a potential for more accurate precipitation forecasting. C1 NOAA, Natl Severe Storms Lab, Norman, OK 73069 USA. NOAA, NWS, W Gulf River Forecast Ctr, Ft Worth, TX USA. RP Hall, T (reprint author), NOAA, Natl Severe Storms Lab, 1313 Halley Circle, Norman, OK 73069 USA. RI Doswell III, Charles/E-7662-2010 NR 22 TC 69 Z9 75 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 JUN PY 1999 VL 14 IS 3 BP 338 EP 345 DI 10.1175/1520-0434(1999)014<0338:PFUANN>2.0.CO;2 PG 8 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 211PR UT WOS:000081169800004 ER PT J AU Nicosia, DJ Grumm, RH AF Nicosia, DJ Grumm, RH TI Mesoscale band formation in three major northeastern United States snowstorms SO WEATHER AND FORECASTING LA English DT Article ID CONDITIONAL SYMMETRICAL INSTABILITY; FRONTAL CIRCULATIONS; FRONTOGENESIS; STABILITY; CYCLONE; DIAGNOSTICS; SYSTEMS; MODELS; STORM AB The National Centers for Environmental Prediction's 29-km version Meso Era Model and Weather Surveillance Radar-1988 Doppler base reflectivity data were used to diagnose intense mesoscale snowbands in three northeastern United States snowstorms. Snowfall rates within these snowbands were extreme and, in one case, were close to 15 cm (6 in.) per hour. The heaviest total snowfall with each snowstorm was largely associated with the positioning of these mesoscale snowbands. Each snowstorm exhibited strong midlevel frontogenesis in conjunction with a deep layer of negative equivalent potential vorticity (EPV). The frontogenesis and negative EPV were found in the deformation zone, north of the developing midlevel cyclone. Cross-sectional analyses (oriented perpendicular to the isotherms) indicated that the mesoscale snowbands formed in close correlation to the intense midlevel frontogenesis and deep layer of negative EPV. It was found that the EPV was significantly reduced on the warm side of the midlevel frontogenetic region as midlevel dry air, associated with a midlevel dry tongue jet, overlaid a low-level moisture-laden easterly jet, north of each low-level cyclone. The continual reduction of EPV on the warm side of the frontogenetic region is postulated to have created the deep layer of negative EPV in the warm advection zone of each cyclone. The negative EPV was mainly associated with conditional symmetric instability (CSI). Each case exhibited a much smaller region of conditional instability (CI) on the warm side of the frontogenesis maximum for a short period of time. The CSI and, to a lesser extent, CI are postulated to have been released as air parcels ascended the moist isentropes, north of the warm front, upon reaching saturation. This likely was a major factor in the mesoscale band formation and heavy snowfall with each snowstorm. The results indicate that model frontogenesis and EPV fields can be used to predict the potential development of mesoscale snowbands. When a deep layer of negative EPV and strong midlevel frontogenesis are forecast by the models, forecasters can anticipate the regions where mesoscale snowbands may form. Inspection of saturation equivalent potential temperature in conjunction with EPV is suggested to determine whether CI is present in a negative EPV region. If CI is present in addition to CSI, then upright convection may dominate over slantwise convection leading to heavier snowfall rates. The region where the frontogenesis and negative EPV are forecast to persist the longest (usually left of the 700-hPa low track) is where the heaviest storm total snowfall will occur. Once mesoscale bands are detected on radar, accurate short-term forecasts of areas that will receive heavy snowfall can be made. C1 NOAA, Natl Weather Serv, State Coll, PA USA. RP Natl Weather Serv Off, 227 W Beaver Ave,Suite 402, State Coll, PA 16801 USA. EM nicosia@supercel.met.psu.edu NR 39 TC 41 Z9 42 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0882-8156 EI 1520-0434 J9 WEATHER FORECAST JI Weather Forecast. PD JUN PY 1999 VL 14 IS 3 BP 346 EP 368 DI 10.1175/1520-0434(1999)014<0346:MBFITM>2.0.CO;2 PG 23 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 211PR UT WOS:000081169800005 ER PT J AU Maddox, RA Zaras, DS MacKeen, PL Gourley, JJ Rabin, R Howard, KW AF Maddox, RA Zaras, DS MacKeen, PL Gourley, JJ Rabin, R Howard, KW TI Echo height measurements with the WSR-88D: Use of data from one versus two radars SO WEATHER AND FORECASTING LA English DT Article ID SATELLITE AB The new Doppler radars of the National Weather Service (i.e., the WSR-88D radars) are operated continuously in a volume scanning mode (called Volume Coverage Pattern, VCP) with the elevation tilt angles fixed for several VCPs. Because of the fixed VCPs, the radar data can be used to determine the heights of precipitation echo features only to limits of accuracy that depend upon the elevation angles used in the VCP, the radar beamwidth, and the range of echoes. Data from adjacent WSR-88D radars, if used simultaneously, could reduce significantly the height uncertainties inherent in single radar measurements. This is illustrated for idealized situations and also for an event involving a long-lived, tornadic thunderstorm. The use of coordinated scan strategies and combined data analysis procedures for adjacent WSR-88D radars during significant thunderstorm events should be considered for operational applications. C1 NOAA, Environm Res Labs, Natl Severe Storms Lab, Norman, OK 73069 USA. RP Maddox, RA (reprint author), NWS Off, 520 N Pk Ave,Suite 304, Tucson, AZ 85719 USA. RI Gourley, Jonathan/C-7929-2016 OI Gourley, Jonathan/0000-0001-7363-3755 NR 11 TC 11 Z9 11 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 1999 VL 14 IS 3 BP 455 EP 460 DI 10.1175/1520-0434(1999)014<0455:EHMWTW>2.0.CO;2 PG 6 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 211PR UT WOS:000081169800011 ER PT J AU Currie, LA AF Currie, LA TI International recommendations offered on analytical detection and quantification concepts and nomenclature SO ANALYTICA CHIMICA ACTA LA English DT Editorial Material C1 NIST, Gaithersburg, MD 20899 USA. RP Currie, LA (reprint author), NIST, Gaithersburg, MD 20899 USA. NR 0 TC 48 Z9 48 U1 0 U2 11 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0003-2670 J9 ANAL CHIM ACTA JI Anal. Chim. Acta PD MAY 31 PY 1999 VL 391 IS 2 BP 103 EP 103 DI 10.1016/S0003-2670(99)00103-8 PG 1 WC Chemistry, Analytical SC Chemistry GA 206YK UT WOS:000080908000002 ER PT J AU Currie, LA AF Currie, LA TI Nomenclature in evaluation of analytical methods including detection and quantification capabilities (IUPAC Recommendations 1995) SO ANALYTICA CHIMICA ACTA LA English DT Article DE nomenclature; analytical methods; detection; quantification capabilities ID PERFORMANCE-CHARACTERISTICS; ANALYTICAL-CHEMISTRY; CALIBRATION AB This IUPAC nomenclature document has been prepared to help establish a uniform and meaningful approach to terminology, notation, and formulation for performance characteristics of the chemical measurement process (CMP). Following definition of the CMP and its performance characteristics, the document addresses fundamental quantities related to the observed response and calibration, and the complement to the calibration function: the evaluation function. Performance characteristics related to precision and accuracy comprise the heart of the document. These include measures for the means or "expected values" of the relevant chemical quantities, as well as dispersion measures such as variance and standard error. Attention is given also to important issues involving: assumptions, internal and external quality control, estimation, error propagation and uncertainty components, and bounds for systematic error. Special treatment is given to terminology and concepts underlying detection and quantification capabilities in chemical metrology, and the significance of the blank. The document concludes with a note on the important distinction between the sampled population and the target population, especially in relation to the interlaboratory environment. (C) 1995 IUPAC Published by Elsevier Science B.V. All rights reserved. C1 Natl Inst Stand & Technol, Chem Sci & Technol Lab, Gaithersburg, MD 20899 USA. RP Natl Inst Stand & Technol, Chem Sci & Technol Lab, Gaithersburg, MD 20899 USA. EM cunie@nist.gov NR 49 TC 293 Z9 296 U1 4 U2 53 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0003-2670 EI 1873-4324 J9 ANAL CHIM ACTA JI Anal. Chim. Acta PD MAY 31 PY 1999 VL 391 IS 2 BP 105 EP 126 DI 10.1016/S0003-2670(99)00104-X PG 22 WC Chemistry, Analytical SC Chemistry GA 206YK UT WOS:000080908000003 ER PT J AU Currie, LA AF Currie, LA TI Detection and quantification limits: origins and historical overview SO ANALYTICA CHIMICA ACTA LA English DT Article DE detection; quantification; international nomenclature; metrology; IUPAC; ISO ID NOMENCLATURE AB Detection and quantification capabilities represent fundamental performance characteristics of measurement processes, yet there have been decades of confusion and miscommunication regarding the underlying concepts and terminology. New, coordinated documents prepared for the International Union of Pure and Applied Chemistry (IUPAC) [L.A. Currie, IUPAC Commission on Analytical Nomenclature, Recommendations in Evaluation of Analytical Methods including Detection and Quantification Capabilities, Pure Appl. Chem. 67 (1995) 1699-1723] and the International Organization for Standardization (ISO) [P. Wilrich, Chairman, ISO/DIS 11843-1,2 (1995), Capability of Detection, ISO/TC69/SC6, ISO Standard, 11843-1, 1977] promise to alleviate this situation by providing, for the first time, a harmonized position on standards and recommendations for adoption by the international scientific community. The text begins with (1) a brief historical summary of detection limits in chemistry, illustrating the critical need for the development of a sound and uniform system of terms and symbols; and (2) a review of the ISO-IUPAC deliberations and the ensuing harmonized position on concepts and nomenclature. In the following text a number of special topics are introduced, including: specification of the measurement process, attention to the meaning and evaluation of "sigma", special considerations for calibration (or regression)-based detection and quantification limits, the central role of the blank, and finally, some challenges for the future. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Currie, LA (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NR 15 TC 214 Z9 219 U1 4 U2 46 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0003-2670 J9 ANAL CHIM ACTA JI Anal. Chim. Acta PD MAY 31 PY 1999 VL 391 IS 2 BP 127 EP 134 DI 10.1016/S0003-2670(99)00105-1 PG 8 WC Chemistry, Analytical SC Chemistry GA 206YK UT WOS:000080908000004 ER PT J AU Crawford, TM Silva, TJ Teplin, CW Rogers, CT AF Crawford, TM Silva, TJ Teplin, CW Rogers, CT TI Subnanosecond magnetization dynamics measured by the second-harmonic magneto-optic Kerr effect SO APPLIED PHYSICS LETTERS LA English DT Article ID FILM AB We have measured the in-plane magnetization dynamics of Ni81Fe19 films using the surface- and interface-sensitive second-harmonic magneto-optic Kerr effect. The dynamical magnetization was measured on patterned Ni81Fe19 stripes as a function of an in-plane magnetic field applied parallel to the anisotropy axis. The excitation sources were 100 ps risetime magnetic field impulses and steps. The minimum magnetization switching times were <300 ps, and precessional free-induction decay was observed. The dynamics for both impulse and step excitation are fitted to the Landau-Lifshitz equation, yielding values for the anisotropy field, gyroscopic splitting factor, and damping. The local surface precessional frequency and anisotropy are different from the average bulk values, demonstrating that this technique possesses the necessary sensitivity to detect variations in localized surface and interface dynamics. (C) 1999 American Institute of Physics. [S0003-6951(99)00622-1]. C1 Natl Inst Stand & Technol, Div Electromagnet Technol, Boulder, CO 80303 USA. Univ Colorado, Dept Phys, Condensed Matter Lab, Boulder, CO 80309 USA. RP Crawford, TM (reprint author), Seagate Res, PLP-II Suite 201,1520 Penn Ave, Pittsburgh, PA 15222 USA. RI Silva, Thomas/C-7605-2013 OI Silva, Thomas/0000-0001-8164-9642 NR 13 TC 74 Z9 76 U1 0 U2 12 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD MAY 31 PY 1999 VL 74 IS 22 BP 3386 EP 3388 DI 10.1063/1.123353 PG 3 WC Physics, Applied SC Physics GA 199HC UT WOS:000080474300048 ER PT J AU Geltman, S AF Geltman, S TI Dissociation dynamics of H-2(+) with short intense laser pulses: a close-coupling study SO JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS LA English DT Article ID IONIZATION; FIELDS; PHOTODISSOCIATION; MOLECULES; H-2+; D2+ AB A full close-coupling calculation is carried out for the dissociation of H-2(+) (Is sigma(g)) by strong, short laser pulses. This is done in the approximation of 'no rotation' and with the retention of only the two lowest electronic states. The basis set consists of the bound vibrational states and a number of groups of dissociating states that represent all the 'essential' continuum states needed to achieve full numerical convergence for the dissociation probabilities. The initial states upsilon = 4 and 7 were studied with laser wavelengths giving strong initial coupling to the continuum, pulse durations of 15 and 150 fs, and peak laser intensities up to 1 x 10(13) W cm(-2). The case of weak initial coupling to the continuum was also studied for 150 fs pulses and a wide range of intensifies for the initial states upsilon = 3, 4 and 5. 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 17 TC 8 Z9 8 U1 0 U2 2 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 1999 VL 32 IS 10 BP 2309 EP 2322 DI 10.1088/0953-4075/32/10/302 PG 14 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 204EB UT WOS:000080749200004 ER PT J AU Solomon, S Portmann, RW Sanders, RW Daniel, JS Madsen, W Bartram, B Dutton, EG AF Solomon, S Portmann, RW Sanders, RW Daniel, JS Madsen, W Bartram, B Dutton, EG TI On the role of nitrogen dioxide in the absorption of solar radiation SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID ACCURATE PARAMETERIZATION; VISIBLE SPECTROSCOPY; CLOUD ABSORPTION; MCMURDO-STATION; CROSS-SECTIONS; CLIMATE MODELS; NO2; THUNDERSTORMS; TEMPERATURE; SURFACE AB Direct measurements of the absorption of downwelling visible radiation by nitrogen dioxide are presented. The data show that this gas can contribute significantly to local radiative forcing under certain conditions. The observed enhancements in nitrogen dioxide absorption are likely to be due both to pollution and to production by lightning in convective clouds. Case studies of several days of observations in Colorado reveal peak absorption of downwelling radiation by NO, of up to 5-12%, corresponding to an estimated local radiative forcing that is likely to be in the range of 5-30 W/m(2). The amount of local forcing associated with thunderstorm activity depends strongly upon the cloud optical depth and on where the NO2 resides within the clouds. These case studies suggest that NO2 can play a significant role in the absorption of radiation (including but not limited to anomalous cloud absorption) either under polluted conditions or when electrically active storms are considered. C1 NOAA, Aeron Lab, ERL, Boulder, CO 80303 USA. NOAA, Climate Monitoring & Diagnost Lab, ERL, Boulder, CO 80303 USA. NOAA, Environm Technol Lab, ERL, Boulder, CO 80303 USA. RP NOAA, Aeron Lab, ERL, 325 Broadway, Boulder, CO 80303 USA. EM solomon@al.noaa.gov RI Portmann, Robert/C-4903-2009; Daniel, John/D-9324-2011 OI Portmann, Robert/0000-0002-0279-6087; NR 48 TC 93 Z9 99 U1 0 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 MAY 27 PY 1999 VL 104 IS D10 BP 12047 EP 12058 DI 10.1029/1999JD900035 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 200XX UT WOS:000080566500013 ER PT J AU Atkinson, DB Hudgens, JW AF Atkinson, DB Hudgens, JW TI Rate coefficients for the propargyl radical self-reaction and oxygen addition reaction measured using ultraviolet cavity ring-down spectroscopy SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID KINETIC DATA-BASE; PHOTODISSOCIATION DYNAMICS; COMBUSTION CHEMISTRY; C3H3 RADICALS; RATE-CONSTANT; 193 NM; ALLENE; PHOTOLYSIS; METHYLACETYLENE; PYROLYSIS AB By using 193 nm laser photolysis and cavity ring-down spectroscopy to produce and monitor the propargyl radical (CH2CCH), the self-reaction and oxygen termolecular association rate coefficients for the propargyl radical were measured at 295 K between total pressures of 300 Pa and 13300 Pa (2.25 and 100 Torr) in Ar, He, and N-2 buffer gases. The rate coefficients obtained by simple second-order fits to the decay data were observed to vary with the photolytic precursors: allene, propargyl chloride, and propargyl bromide. By using a numerical fitting routine and more comprehensive mechanisms, a distinct rate coefficient for the self-reaction was determined, k(infinity)(C3H3+C3H3) = (4.3 +/- 0.6) x 10(-11) cm(3) molecule(-1) s(-1) at 295 K. This rate coefficient which is a factor of 2.8 times slower than reported previously, was independent of total pressure and buffer choice over the entire pressure range. Other rate coefficients derived during the modeling included k(C3H3+H 665 Pa He) = (2.5 +/- 1.1) x 10(-10) cm(3) molecule(-1) s(-1), k(C3H3+C3H3Cl2) = (7 +/- 4) x 10(-11) cm(3) molecule(-1) s(-1), and k(C3H3+C3H3Br2) = (2.4 +/- 2) x 10(-11) cm(3) molecule(-1) s(-1). The association reaction C3H3+O-2 was found to lie in the falloff region between linear and saturated pressure dependence for each buffer gas (Ar, He, and N-2) between 300 Pa and 13300 Pa. A fit of these data derived the high-pressure limiting rate coefficient k(infinity)(C3H3+O-2) = (2.3 +/- 0.5) x 10(-13) cm(3) molecule(-1) s(-1). Three measurements of the propargyl radical-absorption cross-section obtained sigma(332.5) = (413 +/- 60) x 10(-20) cm(2) molecule(-1) at 332.5 nm. Stated uncertainties are two standard deviations and include the uncertainty of the absorption cross section, where appropriate. C1 Natl Inst Stand & Technol, Phys & Chem Properties Div, Chem Sci & Technol Lab, Gaithersburg, MD 20899 USA. RP Atkinson, DB (reprint author), Portland State Univ, Dept Chem, Portland, OR 97207 USA. NR 52 TC 94 Z9 94 U1 1 U2 20 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 27 PY 1999 VL 103 IS 21 BP 4242 EP 4252 DI 10.1021/jp990468s PG 11 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 202HP UT WOS:000080646500017 ER PT J AU Armstrong, DW Schneiderheinze, J Nair, U Magid, LJ Butler, PD AF Armstrong, DW Schneiderheinze, J Nair, U Magid, LJ Butler, PD TI Self-association of rifamycin B: Possible effects on molecular recognition SO JOURNAL OF PHYSICAL CHEMISTRY B LA English DT Article AB The macrocyclic antibiotic rifamycin B was found to be highly surface-active and to aggregate in aqueous solution. The aggregational behavior was studied using small-angle neutron scattering (SANS), Aqueous solutions of rifamycin B showed pronounced scattering at both small-length scales (Q greater than or equal to 0.1 Angstrom(-1)) and at large-length scales ( Q less than or equal to 0.1 Angstrom(-1)). The larger association colloids appear to be rather open low-density aggregates. The addition of 10% 2-propanol greatly reduces the number and size of the aggregates. Somewhat higher amounts of alcohol appear to completely suppress or eliminate aggregation. The suppression of aggregation coincides with the appearance and enhancement of enantioselective association between rifamycin B and a variety of chiral amino alcohols, It appears that the self-aggregation of rifamycin B may be a factor that controls its ability to differentiate between enantiomers in aqueous and hydro-organic solutions. C1 Univ Missouri, Dept Chem, Rolla, MO 65409 USA. Univ Tennessee, Dept Chem, Knoxville, TN 37996 USA. NIST, Ctr Neutron Res, Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Armstrong, DW (reprint author), Univ Missouri, Dept Chem, Rolla, MO 65409 USA. RI Butler, Paul/D-7368-2011 NR 18 TC 5 Z9 5 U1 0 U2 3 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 27 PY 1999 VL 103 IS 21 BP 4338 EP 4341 DI 10.1021/jp990279+ PG 4 WC Chemistry, Physical SC Chemistry GA 202HR UT WOS:000080646700018 ER PT J AU Hellin, J Haigh, H Marks, F AF Hellin, J Haigh, H Marks, F TI Rainfall characteristics of hurricane Mitch SO NATURE LA English DT Letter C1 Univ Greenwich, Nat Resources Inst, Chatham Maritime ME4 4TB, Kent, England. Oxford Brookes Univ, Dept Geog, Oxford OX3 0BP, England. NOAA, Atlantic Oceanog & Meteorol Lab, Hurricane Res Div, Miami, FL 33149 USA. RP Hellin, J (reprint author), Univ Greenwich, Nat Resources Inst, Chatham Maritime ME4 4TB, Kent, England. RI Marks, Frank/A-5733-2011; OI Marks, Frank/0000-0003-0371-5514; Hellin, Jon/0000-0002-2686-8065 NR 5 TC 22 Z9 24 U1 0 U2 1 PU MACMILLAN MAGAZINES LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD MAY 27 PY 1999 VL 399 IS 6734 BP 316 EP 316 DI 10.1038/20577 PG 1 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 200PA UT WOS:000080547800041 ER PT J AU Lue, L Zoeller, N Blankschtein, D AF Lue, L Zoeller, N Blankschtein, D TI Incorporation of nonelectrostatic interactions in the Poisson-Boltzmann equation SO LANGMUIR LA English DT Article ID DOUBLE-LAYER; MONTE-CARLO; ELECTROLYTE; SIMULATION; MACROION AB We develop a general formalism for including nonelectrostatic interactions, such as excluded volume interactions, in the Poisson-Boltzmann (PB) equation. The resulting theory can be applied to any boundary condition and is as easy to numerically implement as the original PB equation. As a specific example, we combine the PB equation with the Boublik-Mansoori-Carnahan-Starling equation of state to model charged hard-sphere systems. This theory is applied to a charged sphere immersed in a salt solution, and the electric field and ion distribution about the sphere are computed. C1 Natl Inst Stand & Technol, Phys & Chem Properties Div, Boulder, CO 80303 USA. MIT, Dept Chem Engn, Cambridge, MA 02139 USA. MIT, Ctr Mat Sci & Engn, Cambridge, MA 02139 USA. RP Lue, L (reprint author), Natl Inst Stand & Technol, Phys & Chem Properties Div, 325 Broadway,M-S 838, Boulder, CO 80303 USA. RI Lue, Leo/E-7846-2011 OI Lue, Leo/0000-0002-4826-5337 NR 24 TC 70 Z9 70 U1 2 U2 14 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0743-7463 J9 LANGMUIR JI Langmuir PD MAY 25 PY 1999 VL 15 IS 11 BP 3726 EP 3730 DI 10.1021/la9813376 PG 5 WC Chemistry, Multidisciplinary; Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA 201RY UT WOS:000080610400007 ER PT J AU DeMarco, B Bohn, JL Burke, JP Holland, M Jin, DS AF DeMarco, B Bohn, JL Burke, JP Holland, M Jin, DS TI Measurement of p-wave threshold law using evaporatively cooled fermionic atoms SO PHYSICAL REVIEW LETTERS LA English DT Article ID BOSE-EINSTEIN CONDENSATION; SCATTERING; GAS; TEMPERATURES; COLLISIONS; HYDROGEN; VAPOR; TRAP AB We have measured independently both s-wave and p-wave cross-dimensional thermalization rates for ultracold K-40 atoms held in a magnetic trap. These measurements reveal that this fermionic isotope has a large positive s-wave triplet scattering length in addition to a low temperature p-wave shape resonance. We have measured directly the p-wave threshold law which, combined with the Fermi statistics, dramatically suppresses elastic collision rates at low temperatures. In addition, we present initial evaporative cooling results that make possible these collision measurements and are a precursor to achieving quantum degeneracy in this neutral, low-density Fermi system. [S0031-9007(99)09214-5]. C1 Natl Inst Stand & Technol, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. Univ Colorado, Dept Phys, Boulder, CO 80309 USA. RP DeMarco, B (reprint author), Natl Inst Stand & Technol, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. OI DeMarco, Brian/0000-0002-2791-0413 NR 32 TC 122 Z9 122 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 MAY 24 PY 1999 VL 82 IS 21 BP 4208 EP 4211 DI 10.1103/PhysRevLett.82.4208 PG 4 WC Physics, Multidisciplinary SC Physics GA 198CX UT WOS:000080405500014 ER PT J AU Rathgeber, S Willner, L Richter, D Brulet, A Farago, B Appel, M Fleischer, G AF Rathgeber, S Willner, L Richter, D Brulet, A Farago, B Appel, M Fleischer, G TI Polymer dynamics in bimodal polyethylene melts: A study with neutron spin echo spectroscopy and pulsed field gradient nuclear magnetic resonance SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID MODE-COUPLING THEORY; SELF-DIFFUSION COEFFICIENT; ENTANGLEMENT CONSTRAINTS; GENERAL FORMULATION; LIQUIDS; REPTATION; SYSTEMS; MOTION; CHAIN; ROUSE AB We have investigated the dynamics of polymers in bimodal polyethylene (PE) melts in the transition region from Rouse- to reptationlike behavior by varying the mass fraction Phi(t) of long tracer chains (N approximate to 3N(e) or 4N(e)) in a short-chain matrix (N approximate to N(e)=entanglement segment number) over the full concentration range. At short times (ns) the dynamic structure factor for single-chain relaxation was investigated by neutron-spin-echo (NSE) spectroscopy. To obtain information about the long-time (ms) dynamics the tracer diffusion coefficient (D(NMR)) was measured by pulsed-field-gradient (PFG)-NMR. We discuss our NSE data within a mode analysis which includes the relaxation rates W(p) of the independent normal modes of the internal chain dynamics and the center-of-mass diffusion coefficient D(NSE) as model parameters. Only modes exceeding the Phi(t)-dependent length of a single entanglement strand N(e)(Phi(t)) are found to be strongly hindered by topological constraints. The D(NSE) are Phi(t)-independent and systematically faster than the strong concentration-dependent D(NMR), suggesting an effective time-dependent diffusion coefficient. The Hess model, which we have generalized for polydisperse melts, provides a time-dependent diffusion coefficient. Taking chain-end effects into account we get an excellent description of the NSE data. The mobility of the chain ends is much higher than the mobility of the inner segments resulting in an entanglement segment number which increases with decreasing tracer concentration. The concentration dependence of N(e)(Phi(t)), as obtained from the mode analysis and the Hess model, is in agreement with our calculation within a self-consistent modification of the model by Kavassalis and Noolandi for entanglement formation. (C) 1999 American Institute of Physics. [S0021-9606(99)50520-5]. C1 Forschungszentrum Julich, Inst Festkorperforsch, D-52425 Julich, Germany. Lab L Brillouin Spectrometrie Neutr, CE Saclay, F-91191 Gif Sur Yvette, France. Inst Max Von Laue Paul Langevin, F-38042 Grenoble, France. RP Rathgeber, S (reprint author), Natl Inst Stand & Technol, Ctr Neutron Res, 100 Bur Dr,Stop 8562, Gaithersburg, MD 20899 USA. EM silke.rathgeber@nist.gov RI Farago, Bela/H-4544-2012; Richter, Dieter/H-3701-2013 OI Richter, Dieter/0000-0003-0719-8470 NR 39 TC 12 Z9 12 U1 3 U2 9 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD MAY 22 PY 1999 VL 110 IS 20 BP 10171 EP 10187 DI 10.1063/1.478890 PG 17 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 197MC UT WOS:000080367700042 ER PT J AU Montes, H Monkenbusch, M Willner, L Rathgeber, S Fetters, L Richter, D AF Montes, H Monkenbusch, M Willner, L Rathgeber, S Fetters, L Richter, D TI Neutron spin echo investigation of the concentration fluctuation dynamics in melts of diblock copolymers SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID BLOCK-COPOLYMERS; MICROPHASE SEPARATION; SEGMENTAL DYNAMICS; LIGHT-SCATTERING; ORDERED PHASES; TRANSITION; DISORDER; TEMPERATURE; RELAXATION; SIMULATION AB Diblock copolymers in the melt exhibit order-disorder phase transitions (ODT), which are accompanied by strong concentration fluctuations. These transitions are generally described in terms of the random phase approximation (RPA) of Leibler and Fredrickson, which is able to explain small angle scattering results in the neighborhood of the ODT, in particular around the correlation peak at q*. The RPA theory has been extended to include dynamical phenomena, predicting the short time relaxation of the dynamic structure factor in polymeric multicomponent systems. We report small angle neutron scattering and neutron spin echo experiments on polyethylene-block-polyethylethylene (PE-PEE) and poly(ethylene-propylene)-block-polyethylethylene (PEP-PEE) copolymers with molecular weights of 16.500 and 68.000 g/mol, which explore the structure and dynamics of these block copolymers. Studying melts with different hydrogen/deuterium labeling it was possible to observe experimentally the different relaxation modes of such systems separately. In particular the collective relaxation behavior as well as the single chain motion were accessed. The experimental results were quantitatively compared with the RPA predictions, which were based solely on the dynamical properties of the corresponding homopolymers and the static structure factors. The collective dynamics exhibits an unanticipated fast relaxation mode. This mode is most visible at low wave numbers (q greater than or equal to q*) but extends to length scales considerably shorter than the radius of gyration. Furthermore, the dynamical RPA yields expressions for the mobilities of chain segments in the block copolymer melt. These combination rules are at variance with the experimental findings for the single chain dynamics, while they hold for the collective response. (C) 1999 American Institute of Physics. [S0021-9606(99)52120-X]. C1 ESPCI, F-75005 Paris, France. Forschungszentrum Julich, Inst Festkorperforsch, D-52425 Julich, Germany. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. ExxonMobil Res & Engn Co, Corp Res Labs, Annandale, NJ 08801 USA. RP Montes, H (reprint author), ESPCI, 10 Rue Vauquelin, F-75005 Paris, France. RI Richter, Dieter/H-3701-2013 OI Richter, Dieter/0000-0003-0719-8470 NR 36 TC 14 Z9 14 U1 0 U2 2 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD MAY 22 PY 1999 VL 110 IS 20 BP 10188 EP 10202 DI 10.1063/1.478891 PG 15 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 197MC UT WOS:000080367700043 ER PT J AU Deslattes, RD Kessler, EG Owens, S Black, D Henins, A AF Deslattes, RD Kessler, EG Owens, S Black, D Henins, A TI Just how perfect can a perfect crystal be? SO JOURNAL OF PHYSICS D-APPLIED PHYSICS LA English DT Article; Proceedings Paper CT 4th Biennial Conference on High Resolution X-ray Diffraction and Topography (XTOP 98) CY SEP 09-11, 1998 CL UNIV DURHAM, DURHAM, ENGLAND HO UNIV DURHAM ID SILICON AB This overview addresses certain aspects of the perfection of the current generation of commercially manufactured monocrystalline silicon, specifically lattice uniformity and the more complex issues of interstitials, vacancies, and chemical impurities. The application areas considered are gamma-ray spectroscopy, and the x-ray/crystal density approach to determination of the Avogadro constant. Some current imperfections, for which we show evidence, appear addressable by technical improvements in the production process, have a much larger effect than is expected from intrinsic limitations emerging from recent model calculations. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Deslattes, RD (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NR 18 TC 9 Z9 9 U1 0 U2 3 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0022-3727 J9 J PHYS D APPL PHYS JI J. Phys. D-Appl. Phys. PD MAY 21 PY 1999 VL 32 IS 10A SI SI BP A3 EP A7 DI 10.1088/0022-3727/32/10A/301 PG 5 WC Physics, Applied SC Physics GA 203VZ UT WOS:000080730000002 ER PT J AU Alpert, BK AF Alpert, BK TI Hybrid Gauss-trapezoidal quadrature rules SO SIAM JOURNAL ON SCIENTIFIC COMPUTING LA English DT Article DE Euler-Maclaurin formula; Gaussian quadrature; high-order convergence; numerical integration; positive weights; singularity ID INTEGRAL-EQUATIONS; SINGULAR FUNCTIONS; ALGORITHM AB A new class of quadrature rules for the integration of both regular and singular functions is constructed and analyzed. For each rule the quadrature weights are positive and the class includes rules of arbitrarily high-order convergence. The quadratures result from alterations to the trapezoidal rule, in which a small number of nodes and weights at the ends of the integration interval are replaced. The new nodes and weights are determined so that the asymptotic expansion of the resulting rule, provided by a generalization of the Euler-Maclaurin summation formula, has a prescribed number of vanishing terms. The superior performance of the rules is demonstrated with numerical examples and application to several problems is discussed. C1 Natl Inst Stand & Technol, Boulder, CO 80303 USA. RP Alpert, BK (reprint author), Natl Inst Stand & Technol, 325 Broadway, Boulder, CO 80303 USA. EM alpert@boulder.nist.gov NR 25 TC 78 Z9 78 U1 2 U2 10 PU SIAM PUBLICATIONS PI PHILADELPHIA PA 3600 UNIV CITY SCIENCE CENTER, PHILADELPHIA, PA 19104-2688 USA SN 1064-8275 J9 SIAM J SCI COMPUT JI SIAM J. Sci. Comput. PD MAY 21 PY 1999 VL 20 IS 5 BP 1551 EP 1584 DI 10.1137/S1064827597325141 PG 34 WC Mathematics, Applied SC Mathematics GA 199TD UT WOS:000080497600001 ER PT J AU Pan, Q Gonzalez, GB Composto, RJ Wallace, WE Arkles, B Figge, LK Berry, DH AF Pan, Q Gonzalez, GB Composto, RJ Wallace, WE Arkles, B Figge, LK Berry, DH TI Spin-on-glass thin films prepared from a novel polysilsesquioxane by thermal and ultraviolet-irradiation methods SO THIN SOLID FILMS LA English DT Article DE dielectrics; polymers; Rutherford backscattering spectroscopy; silicon oxide ID LOW-DIELECTRIC-CONSTANT; 170.5-DEGREES BACKSCATTERING; CROSS-SECTIONS; HE-4 ENERGIES; POLYMERS; TRANSFORMATION; DEPOSITION; LAYERS; OXYGEN; CARBON AB New dielectric films are prepared by both pyrolytic and photolytic conversion of beta-chloroethyl-silsesquioxane (BCESSQ). Film thickness, refractive index, composition, density and morphology are characterized using a palette of techniques including ellipsometry, Rutherford backscattering and forward recoil spectrometry, X-ray reflectivity, and atomic force and electron microscopies. After annealing at 350 degrees C, BCESSQ films, initially 200 nm thick reach about 55% of their original thickness after 20 min. For films heated in air for 4 h, the atom fractions of carbon and hydrogen monotonically decrease to 10 and 30%, respectively, as annealing temperature increases from 225 to 450 degrees C. The BCESSQ reactivity is reflected in the loss of chlorine at 400 degrees C. At 450 degrees C, the film density is 1.88 g/cm(3), or 84% of thermally-grown silicon oxide. Upon exposure to ultraviolet ozone radiation, films ranging from ca. 200 to 700 nm are found to convert to ormosil films within 30 min. Surprisingly, the chlorine concentration is found to decrease more quickly than the hydrogen and carbon concentrations, suggesting that the ormosil him evolves HCl leaving a vinyl group of Si-CH=CH2. This reaction pathway differs from the thermal case. For films prepared by pyrolytic and photolytic methods, atomic force and electron microscopy studies show that the surface is smooth and featureless, the bulk is void free when view at a magnification of 50 000 x, and the ormosil/substrate interface is continuous. (C) 1999 Elsevier Science S.A. All rights reserved. C1 Univ Penn, Res Struct Matter Lab, Philadelphia, PA 19104 USA. Univ Penn, Dept Mat Sci & Engn, Philadelphia, PA 19104 USA. Natl Inst Stand & Technol, Div Polymers, Gaithersburg, MD 20899 USA. Gelest Inc, Tullytown, PA 19007 USA. Univ Penn, Dept Chem, Philadelphia, PA 19104 USA. RP Composto, RJ (reprint author), Univ Penn, Res Struct Matter Lab, Philadelphia, PA 19104 USA. OI Arkles, Barry/0000-0003-4580-2579; Berry, Donald/0000-0001-6732-3726 NR 30 TC 13 Z9 13 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 MAY 21 PY 1999 VL 345 IS 2 BP 244 EP 254 DI 10.1016/S0040-6090(98)01740-4 PG 11 WC Materials Science, Multidisciplinary; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Materials Science; Physics GA 206UD UT WOS:000080896900013 ER PT J AU Shaw, JA AF Shaw, JA TI Degree of linear polarization in spectral radiances from water-viewing infrared radiometers SO APPLIED OPTICS LA English DT Article ID SEA-SURFACE; EMISSION POLARIZATION; CONTRAST; RECOGNITION AB Infrared radiances from water become partially polarized at oblique viewing angles through both emission and reflection. I describe computer simulations that show how the state of polarization for water varies with environmental conditions over a wavelength range of 3-15 mu m with 0.05-mu m resolution. Polarization at wavelengths longer than approximately 4 mu m generally is negative (p, or vertical) and increases with incidence angle up to approximately 75 degrees, beyond which the horizontally polarized reflected atmospheric radiance begins to dominate the surface emission. The highest p polarization (similar to 4-10%) is found in the atmospheric window regions of approximately 4-5 and 8-14 mu m. In the 3-5-mu m spectral band, especially between 3 and 4 mu m, reflected atmospheric radiance usually is greater than surface emission, resulting in a net s polarization (horizontal). The results of these simulations agree well with broadband measurements of the degree of polarization for a water surface viewed at nadir angles of 0-75 degrees. C1 NOAA, Environm Technol Lab, Boulder, CO 80303 USA. RP Shaw, JA (reprint author), NOAA, Environm Technol Lab, 325 Broadway, Boulder, CO 80303 USA. EM jshaw@etl.noaa.gov NR 36 TC 48 Z9 51 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 MAY 20 PY 1999 VL 38 IS 15 BP 3157 EP 3165 DI 10.1364/AO.38.003157 PG 9 WC Optics SC Optics GA 197BK UT WOS:000080344600005 PM 18319904 ER PT J AU Ellison, GB Tuck, AF Vaida, V AF Ellison, GB Tuck, AF Vaida, V TI Atmospheric processing of organic aerosols SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID MARINE BOUNDARY-LAYER; CHARACTERIZATION EXPERIMENT ACE-1; CLOUD-CONDENSATION-NUCLEI; CAPE GRIM; ANTHROPOGENIC AEROSOLS; TROPOSPHERIC AEROSOLS; SIZE DISTRIBUTIONS; PEROXY-RADICALS; SEA-SALT; PARTICLES AB We suggest a chemical model for the composition, structure, and atmospheric processing of organic aerosols. This model is stimulated by recent field measurements showing that organic compounds are a significant component of atmospheric aerosols. The proposed model organic aerosol is an "inverted micelle" consisting of an aqueous core that is encapsulated in an inert, hydrophobic organic monolayer. The organic materials that coat the aerosol particles are surfactants of biological origin. We propose a chemical mechanism by which the organic surface layer will be processed by reactions with atmospheric radicals. The net result of an organic aerosol being exposed to an oxidizing atmosphere is the transformation of an inert hydrophobic film to a reactive, optically active hydrophilic layer. Consequently, processed organic aerosols can grow by water accretion and form cloud condensation nuclei, influencing atmospheric radiative transfer. Radiative transfer may be affected directly by the chromophores left on the surface of the aerosol after chemical transformation. The chemical model yields certain predictions which are testable by observations. Among them is a curve of the percent organic material as a function of particle diameter which predicts that a high fraction of the mass of the upper tropospheric aerosol will be organic. Atmospheric processing of organic aerosols will lead to the release of small organic fragments into the troposphere which will play a subsequent role in homogeneous chemistry. Organic aerosols are likely to act as a transport vehicle of organics and other water insoluble compounds into the atmosphere. We speculate that biomass burning will produce a similar coating of surfactants derived from land sources. Finally, it is pointed out that the radical-induced transformation of the surface layer of aerosol particles from hydrophobic to hydrophilic offers an additional means by which the biosphere, through atmospheric chemistry, can affect the radiative balance. C1 Univ Colorado, Dept Chem & Biochem, Boulder, CO 80309 USA. NOAA, Aeron Lab, Boulder, CO 80303 USA. RP Ellison, GB (reprint author), Univ Colorado, Dept Chem & Biochem, Campus Box 215, Boulder, CO 80309 USA. EM barney@jila.colorado.edu; tuck@al.noaa.gov; vaida@colorado.edu RI Tuck, Adrian/F-6024-2011; Vaida, Veronica/N-6069-2014 OI Tuck, Adrian/0000-0002-2074-0538; Vaida, Veronica/0000-0001-5863-8056 NR 82 TC 317 Z9 317 U1 10 U2 76 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 20 PY 1999 VL 104 IS D9 BP 11633 EP 11641 DI 10.1029/1999JD900073 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 198PZ UT WOS:000080434300007 ER PT J AU Businger, S Johnson, R Katzfey, J Siems, S Wang, Q AF Businger, S Johnson, R Katzfey, J Siems, S Wang, Q TI Smart tetroons for Lagrangian air-mass tracking during ACE 1 SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID ASSIMILATION; PREDICTION; SYSTEM; MODEL AB A series of "smart" tetroons was released from shipboard during the recent ACE 1 field experiment designed to monitor changes in the sulfur budget in a remote marine boundary layer (MBL) south of Tasmania, Australia. The smart tetroons were designed at NOAA Air Resources Laboratory Field Research Division to provide air parcel tracking information. The adjective smart here refers here to the fact that the buoyancy of the tetroons automatically adjusts through the action of a pump and valves when the tetroon travels vertically outside a range of pressures set prior to tetroon release. The smart tetroon design provides GPS location, barometric pressure, temperature, relative humidity, and tetroon status data via a transponder to the NCAR C-130 research aircraft flying in the vicinity of the tetroons. In this paper we will describe (1) the design and capability of the smart tetroons and their performance during the two Lagrangian experiments conducted during ACE 1, (2) the synoptic context of the Lagrangians, including the origin of the air parcels being tracked, and (3) the results of trajectory predictions derived from the National Center for Environmental Prediction (NCEP) Global Spectral Model (GSM) and Australia's Commonwealth Scientific and Industrial Research Organization (CSIRO) Division of Atmospheric Research (DAR) limited-area model. C1 Univ Hawaii, Dept Meteorol, Honolulu, HI 96822 USA. NOAA, Air Resources Lab, Field Res Div, Idaho Falls, ID USA. CSIRO, Div Atmospher Res, PMB 1, Aspendale, Vic 3195, Australia. Monash Univ, Ctr Dynam Meteorol & Oceanog, Clayton, Vic 3168, Australia. USN, Postgrad Sch, Dept Meteorol, Monterey, CA 93943 USA. RP Businger, S (reprint author), Univ Hawaii, Dept Meteorol, 2525 Correa Rd, Honolulu, HI 96822 USA. EM businger@soest.hawaii.edu RI Siems, Steven/C-8339-2013; Katzfey, Jack/K-1231-2012; OI Katzfey, Jack/0000-0002-0604-8860; Siems, Steven/0000-0002-8478-533X NR 19 TC 20 Z9 20 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 20 PY 1999 VL 104 IS D9 BP 11709 EP 11722 DI 10.1029/1998JD100094 PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 198PZ UT WOS:000080434300012 ER PT J AU Knyazev, VD Tsang, W AF Knyazev, VD Tsang, W TI Incorporation of non-steady-state unimolecular and chemically activated kinetics into complex kinetic schemes. 1. Isothermal kinetics at constant pressure SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID MASTER EQUATION ANALYSIS; VIBRATIONAL-RELAXATION; INCUBATION TIMES; ENERGY-TRANSFER; DECOMPOSITION; DISSOCIATION; NORBORNENE; RADICALS; BOND AB A general method of accounting for non-steady-state unimolecular kinetics of reactive species in complex kinetic schemes is described. The method is based on dividing the overall population of affected species into virtual components corresponding to individual eigenvectors of the master equation matrix. It is shown that these individual virtual components are in their respective steady states and evolve independently of each other. The overall treatment is significantly simplified by the fact that only several of these virtual components need to be considered explicitly, and the contribution of the remainder can be described jointly as resulting in ordinary chemical branching. The described method reduces the problem of non-steady-state kinetics to a modest kinetic scheme which can be solved by standard techniques. C1 Catholic Univ Amer, Dept Chem, Washington, DC 20064 USA. NIST, Phys & Chem Properties Div, Gaithersburg, MD 20899 USA. RP Knyazev, VD (reprint author), Catholic Univ Amer, Dept Chem, Washington, DC 20064 USA. NR 31 TC 27 Z9 27 U1 1 U2 8 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD MAY 20 PY 1999 VL 103 IS 20 BP 3944 EP 3954 DI 10.1021/jp984423n PG 11 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 200XK UT WOS:000080565300020 ER PT J AU Guyard, L Hapiot, P Jouini, M Lacroix, JC Lagrost, C Neta, P AF Guyard, L Hapiot, P Jouini, M Lacroix, JC Lagrost, C Neta, P TI Oxidative coupling of small oligothiophenes and oligopyrroles in water in the presence of cyclodextrin. Pulse radiolysis investigations SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID BETA-CYCLODEXTRIN; PHOTOCHEMICAL GENERATION; THIOPHENE OLIGOMERS; CATION RADICALS; ONE-ELECTRON; PYRROLE; POLYMERIZATION; ELECTROCHEMISTRY; COMPLEXATION; POTENTIALS AB The oxidation of small oligothiophenes and oligopyrroles (bipyrroles) has been investigated by pulse radiolysis in aqueous solutions containing hydroxypropyl-beta-cyclodextrin. Oxidation by the N-3(.), Cl-2(.-), or Br-2(.-) radicals produces the corresponding radical cations, which are identical to those observed in organic solvent. Detailed kinetic studies with methylbipyrrole show that the homogeneous oxidation occurs after dissociation of the complex but also with the complex itself, contrarily to what is commonly described for electrochemical reduction or oxidation. The produced cation radical is not associated with the cylodextrin and is rapidly expelled from the host after its formation. On the contrary, if the cation radical is deprotonated to form the neutral radical, the neutral radical is associated with the cyclodextrin. Dissociation kinetics rate constants were found to be fast for both cation radical and neutral radical. C1 Univ Paris 07, Electrochim Mol Lab, CNRS, Unite Mixte Rech 7591, F-75251 Paris 05, France. Univ Paris 07, Inst Topol & Dynam Syst, CNRS, UPRESA 7086, F-75005 Paris, France. Univ Franche Comte, Lab Chim & Electrochim Mol, F-25030 Besancon, France. Natl Inst Stand & Technol, Phys & Chem Properties Div, Gaithersburg, MD 20889 USA. RP Guyard, L (reprint author), Univ Paris 07, Electrochim Mol Lab, CNRS, Unite Mixte Rech 7591, 2 Pl Jussieu,Case Courrier 7107, F-75251 Paris 05, France. NR 32 TC 16 Z9 16 U1 2 U2 4 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 20 PY 1999 VL 103 IS 20 BP 4009 EP 4015 DI 10.1021/jp9900887 PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 200XK UT WOS:000080565300028 ER PT J AU Bennemann, C Donati, C Baschnagel, J Glotzer, SC AF Bennemann, C Donati, C Baschnagel, J Glotzer, SC TI Growing range of correlated motion in a polymer melt on cooling towards the glass transition SO NATURE LA English DT Article ID SUPERCOOLED LIQUIDS; DYNAMICS; HETEROGENEITIES; TEMPERATURE; RELAXATION; INTERFACE AB Many liquids cooled to low temperatures form glasses (amorphous solids) instead of crystals. As the glass transition is approached, molecules become localized and relaxation times increase by many orders of magnitude(1). Many features of this 'slowing down' are reasonably well described(2) by the mode-coupling theory of supercooled liquids(3). The ideal form of this theory predicts a dynamical critical temperature T-c at which the molecules become permanently trapped in the 'cage' formed by their neighbours, and vitrification occurs. Although there is no sharp transition, because molecules do eventually escape their cage, its signature can still be observed in real and simulated liquids. Unlike conventional critical phenomena (such as the behaviour at the liquid-gas critical point), the mode-coupling transition is not accompanied by a diverging static correlation length. But simulation(4-10) and experiment(11,12) show that liquids are dynamically heterogeneous, suggesting the possibility of a relevant 'dynamical' length scale characterizing the glass transition. Here we use computer simulations to investigate a melt of short, unentangled polymer chains over a range of temperatures for which the mode-coupling theory remains valid. We find that although density fluctuations remain short-ranged, spatial correlations between monomer displacements become long-ranged as T-c is approached on cooling. In this way, we identify a growing dynamical correlation length, and a corresponding order parameter, associated with the glass transition. This finding suggests a possible connection between well established concepts in critical phenomena and the dynamics of glass-forming liquids. C1 NIST, Ctr Theoret & Computat Mat Sci, Gaithersburg, MD 20899 USA. NIST, Div Polymers, Gaithersburg, MD 20899 USA. Univ Rome La Sapienza, Dipartimento Fis, I-00185 Rome, Italy. Univ Rome La Sapienza, Ist Nazl Fis Mat, I-00185 Rome, Italy. Univ Mainz, Inst Phys, D-55099 Mainz, Germany. RP Glotzer, SC (reprint author), NIST, Ctr Theoret & Computat Mat Sci, Gaithersburg, MD 20899 USA. RI Donati, Claudio/J-5180-2012; OI Donati, Claudio/0000-0001-8688-1651 NR 26 TC 292 Z9 291 U1 2 U2 60 PU MACMILLAN MAGAZINES LTD PI LONDON PA PORTERS SOUTH, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD MAY 20 PY 1999 VL 399 IS 6733 BP 246 EP 249 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 198MF UT WOS:000080427400051 ER PT J AU Palmisano, AN Winton, JR Dickhoff, WW AF Palmisano, AN Winton, JR Dickhoff, WW TI Sequence features and phylogenetic analysis of the stress protein Hsp90 alpha in chinook salmon (Oncorhynchus tshawytscha), a poikilothermic vertebrate SO BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS LA English DT Article DE Hsp09 alpha; stress protein; heat shock protein; phylogeny; sequence; poikilothermic; chinook salmon; evolution; phosphorylation sites; CKII; leucine zipper ID HEAT-SHOCK-PROTEIN; REGULATED EIF-2-ALPHA KINASE; HSP90-BASED CHAPERONE SYSTEM; SIGNAL-TRANSDUCTION; BINDING PROTEINS; TYROSINE KINASE; TRANSCRIPTION FACTOR; GENE-EXPRESSION; MESSENGER-RNA; IN-VIVO AB We cloned and sequenced a chinook salmon Hsp90 cDNA; sequence analysis shows it to be Hsp90 alpha. Phylogenetic analysis supports the hypothesis that cu and beta paralogs of Hsp90 arose as a result of a gene duplication event and that they diverged early in the evolution of vertebrates, before tetrapods separated fi om the teleost lineage. Among several differences distinguishing poikilothermic Hsp90 alpha sequences from their bird and mammal orthologs, the teleost versions specifically lack a characteristic QTQDQP phosphorylation site near the N-terminus. We used the cDNA to develop an RNA (Northern) blot to quantify cellular Hsp90 mRNA levels. Chinook salmon embryonic (CHSE-214) cells responded to heat shock with a rapid rise in Hsp90 mRNA through 4 h, followed by a gradual decline over the next 20 h. Hsp90 mRNA level may be useful as a stress indicator, especially in a laboratory setting or in response to acute heat stress. (C) 1999 Academic Press. C1 US Geol Survey, Biol Resources Div, Western Fisheries Res Ctr, Seattle, WA 98144 USA. Univ Washington, Sch Fisheries, Seattle, WA 98144 USA. Univ Washington, Natl Marine Fisheries Serv, Seattle, WA 98144 USA. RP US Geol Survey, Biol Resources Div, Western Fisheries Res Ctr, 6505 NE 65th St, Seattle, WA 98144 USA. EM aldo_palmisano@usgs.gov NR 71 TC 22 Z9 25 U1 0 U2 2 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0006-291X EI 1090-2104 J9 BIOCHEM BIOPH RES CO JI Biochem. Biophys. Res. Commun. PD MAY 19 PY 1999 VL 258 IS 3 BP 784 EP 791 DI 10.1006/bbrc.1999.0707 PG 8 WC Biochemistry & Molecular Biology; Biophysics SC Biochemistry & Molecular Biology; Biophysics GA 201LK UT WOS:000080596100052 PM 10329464 ER PT J AU Jiao, TJ Pang, Z Burkey, TJ Johnston, RF Heimer, TA Kleiman, VD Heilweil, EJ AF Jiao, TJ Pang, Z Burkey, TJ Johnston, RF Heimer, TA Kleiman, VD Heilweil, EJ TI Ultrafast ring closure energetics and dynamics of cyclopentadienyl manganese tricarbonyl derivatives SO JOURNAL OF THE AMERICAN CHEMICAL SOCIETY LA English DT Article ID QUANTUM YIELDS; INFRARED-SPECTROSCOPY; COMPLEXES; METAL; FEMTOSECOND; PHOTOLYSIS; REACTIVITY; SUBSTITUTION; CR(CO)5; SOLVENT AB Ring closure following flash photolysis in alkane solvents has been detected for several complexes in the series (eta(5)-C5H4R)Mn(CO)(3) where R = COCH3 (1), COCH2SCH3 (2), CO(CH2)(2)SCH3 (3), COCH2OCH3 (4), (CH2)(2)CO2CH3 (5), and CH2CO2CH3 (6). In each case where ring closure occurs, a metal CO is ultimately substituted by the side chain functional group. Photoacoustic calorimetry studies reveal that ring closures occur with rate constants faster than 10(7) s(-1) or between 10(6) and 107 s(-1), or in some cases the ring closure is biphasic with rate constants in both ranges. The enthalpies of CO dissociation followed by ring closure for 2 and 3 are the same (12 kcal/mol) and more favorable than those for 4-6 (25-15 kcal/mol). Studies of 1-3 by transient picosecond to microsecond infrared spectroscopy confirm biphasic dynamics for 2 and 3: ring closure occurs immediately (k > 5 x 10(9) s(-1)) and at slower rates (k = 10(8)-10(6) s(-1)). We propose that some ring closure occurs before solvent coordination and that the remaining ring closure, resulting in the displacement of solvent, is much slower. The relationships of the rates and energetics of ring closure to structure and quantum yields are discussed. C1 Memphis State Univ, Dept Chem, Memphis, TN 38152 USA. Union Univ, Dept Chem, Jackson, TN 38305 USA. Natl Inst Stand & Technol, Phys Lab, Gaithersburg, MD 20899 USA. RP Burkey, TJ (reprint author), Memphis State Univ, Dept Chem, Campus Box 526060, Memphis, TN 38152 USA. RI Kleiman, Valeria/H-7818-2013 OI Kleiman, Valeria/0000-0002-9975-6558 NR 21 TC 30 Z9 30 U1 0 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 MAY 19 PY 1999 VL 121 IS 19 BP 4618 EP 4624 DI 10.1021/ja9832764 PG 7 WC Chemistry, Multidisciplinary SC Chemistry GA 198MP UT WOS:000080428200009 ER PT J AU Hawking, D Craswell, N Thistlewaite, P Harman, D AF Hawking, D Craswell, N Thistlewaite, P Harman, D TI Results and challenges in Web search evaluation SO COMPUTER NETWORKS-THE INTERNATIONAL JOURNAL OF COMPUTER AND TELECOMMUNICATIONS NETWORKING LA English DT Article DE evaluation; search engines; test collection; TREC; methodology AB A frozen 18.5 million page snapshot of part of the Web has been created to enable and encourage meaningful and reproducible evaluation of Web search systems and techniques. This collection is being used in an evaluation framework within the Text Retrieval Conference (TREC) and will hopefully provide convincing answers to questions such as, "Can link information result in better rankings?", "Do longer queries result in better answers?", and, "Do TREC systems work well on Web data?" The snapshot and associated evaluation methods are described and an invitation is extended to participate. Preliminary results are presented for an effectivess comparison of six TREC systems working on the snapshot collection against five well-known Web search systems working over the current Web. These suggest that the standard of document rankings produced by public Web search engines is by no means state-of-the-art. (C) 1999 Published by Elsevier Science B.V. All rights reserved. C1 CSIRO Math & Informat Sci, Canberra, ACT, Australia. ANU, Dept Comp Sci, Canberra, ACT, Australia. NIST, Gaithersburg, MD 20899 USA. RP Hawking, D (reprint author), CSIRO Math & Informat Sci, Canberra, ACT, Australia. NR 20 TC 25 Z9 25 U1 0 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 1389-1286 J9 COMPUT NETW JI Comput. Netw. PD MAY 17 PY 1999 VL 31 IS 11-16 BP 1321 EP 1330 DI 10.1016/S1389-1286(99)00024-9 PG 10 WC Computer Science, Hardware & Architecture; Computer Science, Information Systems; Engineering, Electrical & Electronic; Telecommunications SC Computer Science; Engineering; Telecommunications GA 202PZ UT WOS:000080662500019 ER PT J AU Link, JS Keen, RE AF Link, JS Keen, RE TI A model of salmonid planktivory: field test of a mechanistic approach to size-selection SO ECOLOGICAL MODELLING LA English DT Article DE feeding behavior; lake herring; zooplankton; Lake Superior; Markovian process; deterministic model; components of predation ID SUNFISH LEPOMIS-MACROCHIRUS; ARTEDI REACTIVE VOLUME; PREY SELECTION; APPARENT SIZE; COMMUNITY STRUCTURE; LAKE-SUPERIOR; ZOOPLANKTON; FISH; PROBABILITIES; PREDATION AB A mechanistic model was developed to simulate the planktivory process for the pelagic lake herring (Coregonus artedi) on common crustacean zooplankton of Lake Superior. The model was constructed as a product of probabilities associated with detection, attack, capture and retention. Sensitivity analysis showed that these coefficients were robust and that initial zooplankton density affected the model behavior more than altering the coefficients. The model output provides percent composition of adult lake herring stomach contents. Zooplankton communities from several stations and seasons in Lake Superior were sampled to provide an initializing zooplankton community for the model. Model output was then contrasted with simultaneously field caught lake herring stomachs. The model predictions agreed with the observed stomach contents at an average accuracy of 80%. The overall agreement of the predictions with observed stomach contents is suggestive that the mechanisms modeled track planktivore feeding dynamics adequately. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Michigan Technol Univ, Dept Biol Sci, Houghton, MI 49931 USA. RP Link, JS (reprint author), NE Fisheries Sci Ctr, Natl Marine Fisheries Serv, 166 Water St, Woods Hole, MA 02543 USA. NR 44 TC 4 Z9 5 U1 1 U2 3 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0304-3800 J9 ECOL MODEL JI Ecol. Model. PD MAY 17 PY 1999 VL 117 IS 2-3 BP 269 EP 283 DI 10.1016/S0304-3800(99)00035-6 PG 15 WC Ecology SC Environmental Sciences & Ecology GA 211ZQ UT WOS:000081192100006 ER PT J AU Cundiff, ST Collings, BC Akhmediev, NN Soto-Crespo, JM Bergman, K Knox, WH AF Cundiff, ST Collings, BC Akhmediev, NN Soto-Crespo, JM Bergman, K Knox, WH TI Observation of polarization-locked vector solitons in an optical fiber SO PHYSICAL REVIEW LETTERS LA English DT Article ID BIREFRINGENT; INSTABILITIES; EVOLUTION; DEVICES; LASERS; MEDIA AB We observe polarization-locked vector solitons in a mode-locked fiber laser. Temporal vector solitons have components along both birefringent axes. Despite different phase velocities due to linear birefringence, the relative phase of the components is locked at +/-pi/2. The value of +/-pi/2 and component magnitudes agree with a simple analysis of the Kerr nonlinearity. These fragile phase-locked vector solitons have been the subject of much theoretical conjecture, but have previously eluded experimental observation. C1 Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. Natl Inst Stand & Technol, Boulder, CO 80309 USA. Princeton Univ, Dept Elect Engn, Princeton, NJ 08544 USA. AT&T Bell Labs, Lucent Technol, Holmdel, NJ 07733 USA. Australian Natl Univ, Ctr Opt Sci, Australian Photon Cooperat Res Ctr, Canberra, ACT 0200, Australia. CSIC, Inst Opt, E-28006 Madrid, Spain. RP Cundiff, ST (reprint author), Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. RI Cundiff, Steven/B-4974-2009 OI Cundiff, Steven/0000-0002-7119-5197 NR 19 TC 91 Z9 93 U1 1 U2 6 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 17 PY 1999 VL 82 IS 20 BP 3988 EP 3991 DI 10.1103/PhysRevLett.82.3988 PG 4 WC Physics, Multidisciplinary SC Physics GA 196QW UT WOS:000080319900016 ER PT J AU Kessler, EG Dewey, MS Deslattes, RD Henins, A Borner, HG Jentschel, M Doll, C Lehmann, H AF Kessler, EG Dewey, MS Deslattes, RD Henins, A Borner, HG Jentschel, M Doll, C Lehmann, H TI The deuteron binding energy and the neutron mass SO PHYSICS LETTERS A LA English DT Article ID LATTICE-PARAMETERS; SILICON; CONSTANTS AB A new value for the deuteron binding energy of S(d) = 2.38817007(42)X 10(-3) u is reported based on an absolute wavelength determination of the 2.2 MeV n-p capture gamma-ray using a crystal diffraction spectrometer. A new more precise value for the neutron mass m(n) = 1.00866491637(82) u is obtained by summing this binding energy and the H-2 - H-1 mass difference. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. Inst Max Von Laue Paul Langevin, F-38042 Grenoble, France. RP Kessler, EG (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NR 25 TC 49 Z9 49 U1 0 U2 7 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-9601 J9 PHYS LETT A JI Phys. Lett. A PD MAY 17 PY 1999 VL 255 IS 4-6 BP 221 EP 229 PG 9 WC Physics, Multidisciplinary SC Physics GA 202YZ UT WOS:000080681100004 ER PT J AU Weigel, RS Horton, W Tajima, T Detman, T AF Weigel, RS Horton, W Tajima, T Detman, T TI Forecasting auroral electrojet activity from solar wind input with neural networks SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID GEOMAGNETIC-ACTIVITY; MAGNETOSPHERE AB Neural networks are developed for reconstructing the chaotic attractor in the nonlinear dynamics of the solar wind driven, coupled magnetosphere-ionosphere (MI) system. Two new methods which improve predictive ability are considered: a gating method which accounts for different levels of activity and a preconditioning algorithm which allows the network to ignore very;short time fluctuations during training. The two networks are constructed using the Bargatze et al. [1985] substorm database that contains solar wind speed and interplanetary magnetic field (IMF) along with ionospheric electrojet index, AL. Both networks are found to produce improvements in predictability, and the significance of the performance increase of the gated network is demonstrated using the bootstrap model testing method. C1 Univ Texas, Inst Fus Studies, Austin, TX 78712 USA. NOAA, Space Environm Ctr, Boulder, CO 80303 USA. RP Weigel, RS (reprint author), Univ Texas, Inst Fus Studies, Austin, TX 78712 USA. NR 16 TC 29 Z9 30 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 MAY 15 PY 1999 VL 26 IS 10 BP 1353 EP 1356 DI 10.1029/1999GL900280 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 197PR UT WOS:000080374500002 ER PT J AU Wennberg, PO Salawitch, RJ Donaldson, DJ Hanisco, TF Lanzendorf, EJ Perkins, KK Lloyd, SA Vaida, V Gao, RS Hintsa, EJ Cohen, RC Swartz, WH Kusterer, TL Anderson, DE AF Wennberg, PO Salawitch, RJ Donaldson, DJ Hanisco, TF Lanzendorf, EJ Perkins, KK Lloyd, SA Vaida, V Gao, RS Hintsa, EJ Cohen, RC Swartz, WH Kusterer, TL Anderson, DE TI Twilight observations suggest unknown sources of HOx SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID HETEROGENEOUS CHEMISTRY; PEROXYNITRIC ACID; SULFURIC-ACID; ABSORPTION; PHOTOCHEMISTRY; OVERTONES; NITROGEN; HO2NO2 AB Measurements of the concentrations of OH and HO2 (HOx) in the high-latitude lower stratosphere imply the existence of unknown photolytic sources of HOx. The strength of the additional HOx source required to match the observations depends only weakly on solar zenith angle (SZA) for 80 degrees < SZA < 93 degrees. The wavelengths responsible for producing this HOx must be longer than 650 nm because the flux at shorter wavelengths is significantly attenuated at high SZA by scattering and absorption. Provided that the sources involve only a single photon, the strength of the bonds being broken must be <45 kcal mole(-1). We speculate that peroxynitric acid (HNO4) dissociates after excitation to an unknown excited state with an integrated band cross section of 2-3 x 10(-20) cm(2) molecule(-1) nm (650 < lambda < 1250 nm). C1 CALTECH, Pasadena, CA 91125 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Harvard Univ, Dept Chem, Cambridge, MA 02138 USA. Univ Toronto, Dept Chem, Toronto, ON M5S 1A1, Canada. Univ Colorado, Dept Chem, Boulder, CO 80309 USA. Johns Hopkins Univ, Appl Phys Lab, Laurel, MD 20723 USA. NOAA, Aeron Lab, Boulder, CO 80307 USA. Univ Calif Berkeley, Berkeley, CA 94720 USA. RP Wennberg, PO (reprint author), CALTECH, MS 150-21,1200 E Calif Blvd, Pasadena, CA 91125 USA. EM wennberg@gps.caltech.edu RI Salawitch, Ross/B-4605-2009; Cohen, Ronald/A-8842-2011; Wennberg, Paul/A-5460-2012; Swartz, William/A-1965-2010; Gao, Ru-Shan/H-7455-2013; Vaida, Veronica/N-6069-2014; Donaldson, James/G-7120-2012 OI Salawitch, Ross/0000-0001-8597-5832; Cohen, Ronald/0000-0001-6617-7691; Swartz, William/0000-0002-9172-7189; Vaida, Veronica/0000-0001-5863-8056; Donaldson, James/0000-0002-5090-3318 NR 18 TC 69 Z9 69 U1 0 U2 9 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 1999 VL 26 IS 10 BP 1373 EP 1376 DI 10.1029/1999GL900255 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 197PR UT WOS:000080374500008 ER PT J AU Jelenkovic, BM Phelps, AV AF Jelenkovic, BM Phelps, AV TI Cathode fall-dominated Ar discharge: Transient and steady-state experiments SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID CURRENT ELECTRICAL DISCHARGES; PARALLEL-PLANE ELECTRODES; CURRENT GLOW-DISCHARGE; LOW-PRESSURE; GAS-DENSITY; HYDROGEN DISCHARGES; DC DISCHARGES; ARGON; EXCITATION; OSCILLATIONS AB The time-dependent transition of an Ar discharge from a low-current diffuse or Townsend discharge to a moderately high-current diffuse or abnormal discharge is investigated. We measure the current, voltage, and optical emission transients after a high-voltage pulse is superimposed on the direct current voltage of the low-current discharge. Emission transients are obtained near the cathode, at the end of the steady-state cathode fall, and near the anode. Spatial scans of absolute optical emission at the 750 and 811 nm lines are taken during the development of the cathode fall. These data show the initial growth of current and emission while the electric field is essentially uniform; the early minimum in emission near the anode marking the collapse of the electric field; the motion toward the cathode of the peak of emission; the drop in the discharge voltage, current, and emission during the approach to the steady-state; and the spatial distribution of emission from the steady-state discharge. Measurements are for pressure times electrode separations from 0.5 to 2 Torr cm and steady-state current densities of 500-100 mu A/cm(2), respectively. The initial rate of rise of the discharge voltage is roughly 100 V/mu s and the times required to reach steady state are about 10 mu s. (C) 1999 American Institute of Physics. [S0021-8979(99)02710-3]. C1 Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. Natl Inst Stand & Technol, Boulder, CO 80309 USA. Univ Belgrade, Inst Phys, Belgrade, Serbia Monteneg. Natl Inst Stand & Technol, Div Time & Frequency, Boulder, CO 80303 USA. RP Jelenkovic, BM (reprint author), Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. EM brana@jila.colorado.edu NR 46 TC 20 Z9 20 U1 0 U2 2 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD MAY 15 PY 1999 VL 85 IS 10 BP 7089 EP 7096 PG 8 WC Physics, Applied SC Physics GA 193KT UT WOS:000080136000012 ER PT J AU Karyakin, EN Fraser, GT Loeser, JG Saykally, RJ AF Karyakin, EN Fraser, GT Loeser, JG Saykally, RJ TI Rotation-tunneling spectrum of the deuterated ammonia dimer SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID RESONANCE OPTOTHERMAL SPECTROSCOPY; INFRARED DOUBLE-RESONANCE; MICROWAVE; (NH3)2; DYNAMICS; STATES AB The millimeter and submillimeter-wave molecular-beam spectrum of the perdeuterated ammonia dimer (ND3)(2) has been measured between approximately 50 and 400 GHz using an electric-resonance optothermal spectrometer (EROS). As in the case of the (NH3)(2), the spectrum is complicated by the threefold internal rotation of the ND3 subunits, the interchange tunneling of the two subunits, and the inversion of the subunits through their respective centers of masses. These tunneling motions split the rigid-molecule energy levels into 22 components, which all have nonzero statistical weights in the case of the deuterated dimer. Transitions have been assigned for rotation-tunneling states correlating to A-A (ortho-ortho) combinations of the ND3 monomer states, where A designates the rovibronic symmetries of the ND3 subunits. One K=1<--1, one K=1<--0, one K=0<--1, and two K=0<--0 progressions have been assigned. The data have been fit to 0.28 MHz using linear molecule-type energy-level expressions to determine rotational constants, band origins, l/K-type double constants, and centrifugal distortion constants. The two K=0<--0 subbands, with origins near 264 GHz, are split by 64 MHz due to monomer inversion, as observed previously in the NH3 dimer. The 264 GHz, K=0 splitting arises predominantly from monomer interchange tunneling and is nearly a factor of 2 less than the 483 GHz value for the NH3 dimer. The separation is also approximately 25% smaller than predicted by Olthof et al. [E. H. T. Olthof, A. van der Avoird, and P. E. S. Wormer, J. Chem. Phys. 101, 8430 (1994)] from dynamical calculations on a model potential energy surface adjusted to fit the observed far-infrared rotation-tunneling spectrum of the NH3 dimer. (C) 1999 American Institute of Physics. [S0021-9606(99)01419-1]. C1 Inst Phys Appl, Mol Spect Lab, Nizhnii Novgorod, Russia. Natl Inst Stand & Technol, Opt Technol Div, Gaithersburg, MD 20899 USA. Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA. RP Karyakin, EN (reprint author), Inst Phys Appl, Mol Spect Lab, Nizhnii Novgorod, Russia. NR 20 TC 11 Z9 11 U1 3 U2 6 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD MAY 15 PY 1999 VL 110 IS 19 BP 9555 EP 9559 DI 10.1063/1.478920 PG 5 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 193TV UT WOS:000080154000026 ER PT J AU Maes, C AF Maes, C TI A note on the vertical scales of temperature and salinity and their signature in dynamic height in the western Pacific Ocean: Implications for data assimilation SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID SEA-SURFACE SALINITY; TROPICAL PACIFIC; EQUATORIAL PACIFIC; NORTH-ATLANTIC; TOGA-COARE; PREDICTION; MESOSCALE; PROFILES; SYSTEM; IMPACT AB The relationship between the vertical structures of ocean temperature and salinity and their concurrent signature in surface dynamic height anomalies are investigated along the 165 degrees E transequatorial section in the western Pacific Ocean. The data are from conductivity-temperature depth casts made during 28 oceanographic cruises mainly conducted during the 1984-1992 time period as part of the TOGA program. The analysis is based on empirical orthogonal functions that isolate the primary modes of variability, and some possible physical interpretations are suggested. The results show that the first six modes, explaining roughly 80% of the variance, display distinct vertical scales and exhibit coherent and observable signatures in dynamic height which reveal complex patterns in latitude and time. In addition, a method has been developed to reconstruct the temperature and salinity profiles from their signature in the surface dynamic height anomaly using the dominant EOFs. The method is new in the sense that no recourse is made to T-S relations. Residual errors in the vertical after reconstruction are lower than the intrinsic variability, and the method can successfully reproduce the variability at ENSO timescales. The residual error in dynamic height anomalies is lower than 1 dyn. cm in the equatorial belt, and of the order of 2-4 dyn. cm in the subtropics. The results demonstrate that sea level observations may be translate into temperature and salinity anomalies at depth. The implications for data assimilation in ocean models are discussed. C1 Natl Ctr Environm Predict, NCEP EMC CMB, Camp Springs, MD 20746 USA. RP Maes, C (reprint author), Natl Ctr Environm Predict, NCEP EMC CMB, Room 807,5200 Auth Rd, Camp Springs, MD 20746 USA. RI maes, christophe/L-4049-2015 OI maes, christophe/0000-0001-6532-7141 NR 32 TC 18 Z9 18 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-OCEANS JI J. Geophys. Res.-Oceans PD MAY 15 PY 1999 VL 104 IS C5 BP 11037 EP 11048 DI 10.1029/1999JC900032 PG 12 WC Oceanography SC Oceanography GA 198WX UT WOS:000080448200010 ER PT J AU Donnelly, WJ Carswell, JR McIntosh, RE Chang, PS Wilkerson, J Marks, F Black, PG AF Donnelly, WJ Carswell, JR McIntosh, RE Chang, PS Wilkerson, J Marks, F Black, PG TI Revised ocean backscatter models at C and Ku band under high-wind conditions SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article ID SCATTEROMETRY AB A series of airborne scatterometer experiments designed to collect C and Ku band ocean backscatter data in regions of high ocean surface winds has recently been completed. More than 100 hours of data were collected using the University of Massachusetts C and Ku band scatterometers, CSCAT and KUSCAT. These instruments measure the full azimuthal normalized radar cross section (NRCS) of a common surface area of the ocean simultaneously at four incidence angles. Our results demonstrate limitations of the current empirical models, C band geophysical model function 4 (CMOD4), SeaSat scatterometer 2 (SASS 2), and NASA scatterometer 1 (NSCAT) 1, that relate ocean backscatter to the near-surface wind at high wind speeds. The discussion focuses on winds in excess of 15 m s(-1) in clear atmospheric conditions. The scatterometer data are collocated with measurements from ocean data buoys and Global Positioning System dropsondes, and a Fourier analysis is performed as a function of wind regime. A three-term Fourier series is fit to the backscatter data, and a revised set of coefficients is tabulated. These revised models, CMOD4HW and KUSCAT 1, are the basis for a discussion of the NRCS at high wind speeds. Our scatterometer data show a clear overprediction of the derived NRCS response to high winds based on the CMOD4, SASS 2, and NSCAT 1 models. Furthermore, saturation of the NRCS response begins to occur above 15 m s(-1). Sensitivity of the upwind and crosswind response is discussed with implications toward high wind speed retrieval. C1 Univ Massachusetts, Microwave Remote Sensing Lab, Amherst, MA 01003 USA. NOAA, Off Res & Applicat, Natl Environm Satellite Data & Informat Serv, Camp Springs, MD 20746 USA. NOAA, Hurricane Res Div, Miami, FL 33149 USA. RP Donnelly, WJ (reprint author), Univ Massachusetts, Microwave Remote Sensing Lab, Amherst, MA 01003 USA. RI Chang, Paul/F-5580-2010; Marks, Frank/A-5733-2011 OI Chang, Paul/0000-0001-5113-0938; Marks, Frank/0000-0003-0371-5514 NR 12 TC 79 Z9 83 U1 2 U2 10 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 MAY 15 PY 1999 VL 104 IS C5 BP 11485 EP 11497 DI 10.1029/1998JC900030 PG 13 WC Oceanography SC Oceanography GA 198WX UT WOS:000080448200043 ER PT J AU Wang, CZ Weisberg, RH Yang, HJ AF Wang, CZ Weisberg, RH Yang, HJ TI Effects of the wind speed-evaporation-SST feedback on the El Nino-Southern Oscillation SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID OCEAN-ATMOSPHERE MODEL; SEA-SURFACE TEMPERATURE; SELF-EXCITED OSCILLATIONS; SEASONAL CYCLE; TROPICAL OCEAN; PACIFIC; SYSTEM; VARIABILITY; CHAOS; ENSO AB The thermodynamical process of latent heat flux is added to an analogical delayed oscillator model of the El Nino-Southern Oscillation (ENSO) that mainly considers equatorial ocean dynamics and produces regular, nonphase-locked oscillations. Latent heat flux affects the model sea surface temperature (SST) variations by a positive feedback between the surface wind speed and SST operating through evaporation, which is called the wind speed-evaporation-SST feedback. The wind speed-evaporation-SST feedback in which the atmosphere interacts thermodynamically with the ocean through surface heat flux differs from the conventional zonal wind stress-SST feedback in which the atmsophere interacts dynamically with the ocean through momentum flux. The combination of equatorial ocean dynamics and thermodynamics produces relatively more realistic model oscillations. When the annual cycle amplitude of the zonal wind in the wind speed-evaporation-SST feedback is gradually increased, the model solution undergoes a transition from periodic to chaotic and then to periodic oscillations for some ranges of the parameters, whereas for other ranges of the parameters the transition goes from periodic to quasiperiodic and then to periodic oscillations. The route to chaos is the intermittency route. Along with such irregularity, the nonlinear interactions between the annual and interannual cycles operating through the wind speed-evaporation-SST feedback also produce a phase-locking of ENSO to the seasonal cycle. The model ENSO onset and peak occur in the boreal winter and spring, respectively, consistent with the observed phase-locking of ENSO in the far eastern Pacific. It is shown that ENSO decadal or interdecadal variability may result from the nonlinear interactions between the annual and interannual cycles in the Tropics. C1 Univ S Florida, Dept Marine Sci, St Petersburg, FL 33701 USA. RP Wang, CZ (reprint author), NOAA, Atlantic Oceanog & Meteorol Lab, Phys Oceanog Div, 4301 Rickenbacker Causeway, Miami, FL 33149 USA. RI Wang, Chunzai /C-9712-2009 OI Wang, Chunzai /0000-0002-7611-0308 NR 31 TC 13 Z9 13 U1 0 U2 5 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PD MAY 15 PY 1999 VL 56 IS 10 BP 1391 EP 1403 DI 10.1175/1520-0469(1999)056<1391:EOTWSE>2.0.CO;2 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 194YM UT WOS:000080222400009 ER PT J AU Brown, DW Sokol, PE FitzGerald, SA AF Brown, DW Sokol, PE FitzGerald, SA TI Rotational dynamics of n-H-2 in porous Vycor glass SO PHYSICAL REVIEW B LA English DT Article ID MOLECULAR-HYDROGEN; NEUTRON-SCATTERING; ENERGY-LEVELS; SURFACE AB The rotational kinematics of normal H-2 confined to the pores of Vycor glass have been studied via incoherent inelastic neutron spectroscopy. At low temperature we observe two distinct rotational transitions. One is centered near 14 meV, corresponding to the free rotor value of molecular HZ, while the other is centered at similar to 10 meV. Measurements taken at filling fractions ranging from 10% to 95% allow us to ascribe the two transitions to H-2 in the center of the pore and H-2 strongly bound to the pore surface, respectively. The molecules bound to the surface are modeled as rotationally hindered rotors, and a distribution of orientation-dependent interaction potentials is extracted. The bound molecules can further be divided into a monolayer that is in direct contact with the pore wall, and a second, less tightly bound layer. The ortho to para conversion rate has also been measured and is higher than the bulk rate of 1.9%/h. The rate for the molecules bound to the pore wall is 2.1%/h, while the rate for molecules in the center of the pore is 8.5%/h. [S0163-1829(99)03920-X]. C1 Penn State Univ, Dept Phys, University Pk, PA 16802 USA. Natl Inst Stand & Technol, NIST Ctr Neutron Res, Gaithersburg, MD 20899 USA. RP Brown, DW (reprint author), Univ Calif Los Alamos Natl Lab, MS-H805,BLDG 622,TA-53, Los Alamos, NM 87545 USA. NR 23 TC 14 Z9 14 U1 1 U2 4 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD MAY 15 PY 1999 VL 59 IS 20 BP 13258 EP 13266 DI 10.1103/PhysRevB.59.13258 PG 9 WC Physics, Condensed Matter SC Physics GA 200ZW UT WOS:000080571000073 ER PT J AU Penn, DR Stiles, MD AF Penn, DR Stiles, MD TI Solution of the Boltzmann equation without the relaxation-time approximation SO PHYSICAL REVIEW B LA English DT Article ID LAYERED MAGNETIC-STRUCTURES; GIANT MAGNETORESISTANCE; MULTILAYERS; TRANSPORT; INTERFACE; TRANSMISSION; SCATTERING AB A method is presented for solving the Boltzmann equation in layered systems without the relaxation-time approximation. The solution is compared with that obtained using the relaxation-time approximation for free-electron solids in the presence of boundaries. For the cases studied, most of the differences can be minimized by using the transport relaxation time. For nonfree electron materials it is expected that the differences will be more complex. [S0163-1829(99)05220-0]. C1 NIST, Electron Phys Grp, Gaithersburg, MD 20899 USA. RP Penn, DR (reprint author), NIST, Electron Phys Grp, Gaithersburg, MD 20899 USA. RI Stiles, Mark/K-2426-2012 OI Stiles, Mark/0000-0001-8238-4156 NR 24 TC 16 Z9 16 U1 0 U2 2 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 EI 1550-235X J9 PHYS REV B JI Phys. Rev. B PD MAY 15 PY 1999 VL 59 IS 20 BP 13338 EP 13346 DI 10.1103/PhysRevB.59.13338 PG 9 WC Physics, Condensed Matter SC Physics GA 200ZW UT WOS:000080571000085 ER PT J AU Mossner, SG de Alda, MJL Sander, LC Lee, ML Wise, SA AF Mossner, SG de Alda, MJL Sander, LC Lee, ML Wise, SA TI Gas chromatographic retention behavior of polycyclic aromatic sulfur heterocyclic compounds, (dibenzothiophene, naphtho[b]thiophenes, benzo[b]naphthothiophenes and alkyl-substituted derivatives) on stationary phases of different selectivity SO JOURNAL OF CHROMATOGRAPHY A LA English DT Article DE retention indices; stationary phases, GC; molecular descriptors; retention behavior; polycyclic aromatic compounds; polycyclic aromatic sulfur heterocyclic compounds; thiophenes; naphthothiophenes; benzothiophenes ID SHAPE SELECTIVITY; LIQUID; HYDROCARBONS; INDEXES; RESOLUTION; OILS; C18 AB Retention indices for 80 polycyclic aromatic sulfur heterocyclic compounds (PASHs) were determined by using high-resolution capillary gas chromatography (GC) with three different stationary phases: a 5% (mole fraction) phenyl-substituted methylpolysiloxane column, a 50% (mole fraction) phenyl-substituted methylpolysiloxane column and a smectic Liquid crystalline column. Retention data were obtained for the following PASHs: dibenzothiophene, 28 alkyldibenzothiophenes, naphtho[1,2-b]thiophene, seven of the eight possible methylnaphtho[1,2-b]thiophenes, naphtho[2,1-b]thiophene, all eight methylnaphtho[2, 1-b]thiophenes, naphtho[2,3-b]thiophene, the three benzo[b]naphthothiophene isomers (benzo[b]naphtho[1,2-d]thiophene, benzo[b]naphtho[2,1-d]thiophene and benzo[b]naphtho[2,3-d]thiophene), and all 30 possible methylbenzo[b]naphthothiophene isomers. Molecular descriptors [length, breadth, thickness (T), and length-to-breadth ratio (LIB)] were calculated for all the compounds studied. Correlations for retention on the liquid crystalline phase and solute geometry (LIB and T) ratios were investigated, and the retention was found to be highly correlated with LIE resulting in correlation coefficients ranging from r = 0.68 to r = 0.98. Published by Elsevier Science B.V. C1 Natl Inst Stand & Technol, Chem Sci & Technol Lab, Div Analyt Chem, Gaithersburg, MD 20899 USA. Brigham Young Univ, Dept Chem & Biochem, Provo, UT 84602 USA. RP Wise, SA (reprint author), Natl Inst Stand & Technol, Chem Sci & Technol Lab, Div Analyt Chem, Gaithersburg, MD 20899 USA. RI Lopez de Alda, Miren/E-3357-2014 OI Lopez de Alda, Miren/0000-0002-9347-2765 NR 46 TC 55 Z9 59 U1 1 U2 10 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0021-9673 J9 J CHROMATOGR A JI J. Chromatogr. A PD MAY 14 PY 1999 VL 841 IS 2 BP 207 EP 228 DI 10.1016/S0021-9673(99)00363-5 PG 22 WC Biochemical Research Methods; Chemistry, Analytical SC Biochemistry & Molecular Biology; Chemistry GA 198TC UT WOS:000080439400008 ER PT J AU Rochford, KB Dyer, SD AF Rochford, KB Dyer, SD TI Reconstruction of minimum-phase group delay from fibre Bragg grating transmittance reflectance measurements SO ELECTRONICS LETTERS LA English DT Article AB A technique is presented for reconstructing the group delay of fibre gratings from amplitude data that uses methods from homomorphic signal processing. Phase reconstruction is compared to exact solutions using the reflectance from a uniform grating. An intermediate windowing process improves the recovery accuracy. C1 Natl Inst Stand & Technol, Div Optoelect, Boulder, CO 80303 USA. RP Rochford, KB (reprint author), Natl Inst Stand & Technol, Div Optoelect, 325 Broadway, Boulder, CO 80303 USA. NR 7 TC 6 Z9 6 U1 0 U2 1 PU IEE-INST ELEC ENG PI HERTFORD PA MICHAEL FARADAY HOUSE SIX HILLS WAY STEVENAGE, HERTFORD SG1 2AY, ENGLAND SN 0013-5194 J9 ELECTRON LETT JI Electron. Lett. PD MAY 13 PY 1999 VL 35 IS 10 BP 838 EP 839 DI 10.1049/el:19990546 PG 2 WC Engineering, Electrical & Electronic SC Engineering GA 204DD UT WOS:000080746900056 ER PT J AU Lue, L Woodcock, LV AF Lue, L Woodcock, LV TI Depletion effects and gelation in a binary hard-sphere fluid SO MOLECULAR PHYSICS LA English DT Article ID 5TH VIRIAL-COEFFICIENT; DENSITY-FUNCTIONAL THEORY; PHASE-SEPARATION; INTEGRAL-EQUATION; COMPUTER-SIMULATION; CORE MIXTURES; MONTE-CARLO; CONSISTENT; COLLOIDS AB A study of the binary hard-sphere fluid with size ratio sigma(B)/sigma(A) = 0.1 is reported. Molecular dynamics and Monte Carlo simulations have been carried out over the mole fraction (x(A)) range 0.002-0.1 and over the high density range where several recent authors have predicted a thermodynamic demixing transition on the basis of integral equations. In this region, there is no evidence of such first-order thermodynamic phase separation, or two fluid phases. The effect of the depletion force, arising from the entropic exclusion of B spheres from between two A spheres, as x(B) is increased at constant packing fraction y(A), is to cause a large increase in the partial pressure of A and the radial distribution function of A at contact, a reduction on the mobility of A, and eventually, at a sufficient x(B), the gelation of component A to an open, low coordination, amorphous structure. This gelation transition of A shows discontinuities similar to a glass transition; it can be traced back to the hard sphere glass formation as x(B) approaches zero. Thermodynamic properties are reported over the range studied; and used to evaluate the predictions of current theories and the accuracy of equations of state. The Boublik-Mansoori-Carnahan-Starling-Leland equation is found to be remarkably accurate in this region, over the whole fluid range, but shows systematic deviations at high packing densities. C1 Natl Inst Stand & Technol, Phys & Chem Properties Div, Boulder, CO 80303 USA. Univ Bradford, Dept Chem Engn, Bradford BD7 1DP, W Yorkshire, England. RP Woodcock, LV (reprint author), Natl Inst Stand & Technol, Phys & Chem Properties Div, 325 Broadway,M-S 838, Boulder, CO 80303 USA. RI Lue, Leo/E-7846-2011 OI Lue, Leo/0000-0002-4826-5337 NR 48 TC 50 Z9 51 U1 1 U2 13 PU TAYLOR & FRANCIS LTD PI LONDON PA ONE GUNPOWDER SQUARE, LONDON EC4A 3DE, ENGLAND SN 0026-8976 J9 MOL PHYS JI Mol. Phys. PD MAY 10 PY 1999 VL 96 IS 9 BP 1435 EP 1443 PG 9 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 198HA UT WOS:000080416400014 ER PT J AU Young, BC Cruz, FC Itano, WM Bergquist, JC AF Young, BC Cruz, FC Itano, WM Bergquist, JC TI Visible lasers with subhertz linewidths SO PHYSICAL REVIEW LETTERS LA English DT Article ID OPTICAL FREQUENCY STANDARD; STABILIZATION; LEVEL; RESONATORS; STABILITY; PHASE; ION AB We report a visible laser with a subhertz linewidth for use in precision spectroscopy and as a local oscillator for an optical frequency standard. The laser derives its stability from a well-isolated, high-finesse, Fabry-Perot cavity. For a 563 nm laser beam locked to our stable cavity, we measure a linewidth of 0.6 Hz for averaging times up to 32 s. The fractional frequency instability for the light locked to the cavity is typically 3 X 10(-16) at 1 s. Both the linewidth and fractional frequency instability are approximately an order of magnitude less than previously published results for stabilized lasers. C1 Natl Inst Stand & Technol, Div Time & Frequency, Boulder, CO 80303 USA. RP Young, BC (reprint author), Natl Inst Stand & Technol, Div Time & Frequency, 325 Broadway, Boulder, CO 80303 USA. RI Cruz, Flavio/A-6346-2012 OI Cruz, Flavio/0000-0003-3995-7910 NR 20 TC 393 Z9 405 U1 5 U2 42 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 10 PY 1999 VL 82 IS 19 BP 3799 EP 3802 DI 10.1103/PhysRevLett.82.3799 PG 4 WC Physics, Multidisciplinary SC Physics GA 194RN UT WOS:000080207500018 ER PT J AU Yang, JC Cleary, TG Huber, ML Grosshandler, WL AF Yang, JC Cleary, TG Huber, ML Grosshandler, WL TI Vapour nucleation in a cryogenic-fluid-dissolved-nitrogen mixture during rapid depressurization SO PROCEEDINGS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES LA English DT Article DE cryogenic fluids; fire suppression; homogeneous nucleation; equation of state; fugacity ID EQUATION; PRESSURE; LIQUID; STATE; WATER AB The behaviour of four cryogenic-fluid-dissolved-nitrogen mixtures inside a pressure vessel during rapid depressurization was investigated through experiment. The four fluids studied were CF3I, FC-218 (C3F8), HFC-125 (C2HF5), and CF3Br. Depressurization was achieved by discharging the liquid mixture through a solenoid valve at room temperature. Two initial total vessel pressures were used: (1) ca. 2.8 MPa and (2) ca. 4.2 MPa. Based on the experimental observations obtained by using a highspeed movie camera, the evolution of dissolved nitrogen was suggested for FC-218, HFC-125 and CF3Br in the cases of initial total pressures of ca. 4.2 MPa. For initial vessel pressures of ca. 2.8 MPa, vapour nucleation plas not observed for any of the four fluid-dissolved-nitrogen mixtures. No degassing was observed for CF3I irrespective of the two initial total pressures. The predicted nucleation pressures based on the classical homogeneous nucleation theory for a binary-component mixture provided qualitative agreement with the observed vapour nucleation inside the vessel. C1 Natl Inst Stand & Technol, Bldg & Fire Res Lab, Gaithersburg, MD 20899 USA. Natl Inst Stand & Technol, Chem Sci & Technol Lab, Boulder, CO 80303 USA. RP Yang, JC (reprint author), Natl Inst Stand & Technol, Bldg & Fire Res Lab, Gaithersburg, MD 20899 USA. NR 25 TC 1 Z9 1 U1 0 U2 0 PU ROYAL SOC PI LONDON PA 6-9 CARLTON HOUSE TERRACE, LONDON SW1Y 5AG, ENGLAND SN 1364-5021 EI 1471-2946 J9 P ROY SOC A-MATH PHY JI Proc. R. Soc. A-Math. Phys. Eng. Sci. PD MAY 8 PY 1999 VL 455 IS 1985 BP 1717 EP 1738 PG 22 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 198AY UT WOS:000080400600005 ER PT J AU Wang, YC Christophorou, LG Olthoff, JK Verbrugge, JK AF Wang, YC Christophorou, LG Olthoff, JK Verbrugge, JK TI Electron drift and attachment in CHF3 and its mixtures with argon SO CHEMICAL PHYSICS LETTERS LA English DT Article ID IMPACT; CF4 AB Measurements are reported of the electron drift velocity, w, in CHF3 gas and in its mixtures with argon. The E/N dependence of w in the mixtures exhibits regions of distinct negative differential conductivity. A small electron attachment rate constant (similar to 13 X 10(-14) cm(3) s(-1) for density-reduced electric fields, E/N < 50 X 10(-17) V cm(2)) has been measured, which may be due to impurities. (C) 1999 Elsevier Science B.V. All rights reserved. C1 NIST, Div Elect, Elect & Elect Engn Lab, Gaithersburg, MD 20899 USA. RP Wang, YC (reprint author), NIST, Div Elect, Elect & Elect Engn Lab, Gaithersburg, MD 20899 USA. NR 16 TC 18 Z9 18 U1 0 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 7 PY 1999 VL 304 IS 5-6 BP 303 EP 308 DI 10.1016/S0009-2614(99)00338-3 PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 193PA UT WOS:000080144200002 ER PT J AU Das, TN Huie, RE Neta, P AF Das, TN Huie, RE Neta, P TI Reduction potentials of SO3 center dot-, SO5 center dot-, and S4O6 center dot 3- radicals in aqueous solution SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID PHENOXYL RADICALS; ELECTRON-TRANSFER; PULSE-RADIOLYSIS; CHLORINE DIOXIDE; SO5 RADICALS; OXIDATION; SULFITE; THIOSULFATE; MECHANISM; KINETICS AB Reduction potentials of the SO3.-, SO5.-, and S4O6. 3- radicals in aqueous solutions are measured by pulse radiolysis at 294 K. These radicals are produced by reaction of (OH)-O-. or N-3(.) radicals with sulfite, peroxymonosulfate, and thiosulfate anions, respectively. The potentials for the couples SO3.-/SO32- and SO5.-/SO52- an determined from equilibrium constants with three reference couples of the phenoxyl/phenoxide type, i.e., those derived from phenol, 3-cresol, and tyrosine. The potential for PhO./PhO- is redetermined against ClO2./ClO2- and confirms the published value. The potentials for the other two phenols are determined against PhO./PhO-. The potential for the SO3.-/SO32- couple is found to be 0.73 +/- 0.01 V vs NHE. The potential for SO5.-/SO52- is found to be 0.81 +/- 0.02 V. The reduction potential of the radical formed from the one-electron oxidation of thiosulfate, which exhibits a lambda(max) at 375 nm, is also determined. This radical was identified before as either the monomeric S2O3.- or the dimeric S4O6. 3-. Equilibrium measurements for this species, using N-3(.) and the 4-cyanophenoxyl radical as references, support the dimeric assignment and yield a value of 1.07 +/- 0.03 V for the reduction potential for the couple S4O6. 3-/2S(2)O(3)(2-). C1 Natl Inst Stand & Technol, Phys & Chem Properties Div, Gaithersburg, MD 20899 USA. RP Huie, RE (reprint author), Natl Inst Stand & Technol, Phys & Chem Properties Div, Gaithersburg, MD 20899 USA. RI Huie, Robert/A-5645-2010 NR 49 TC 41 Z9 41 U1 1 U2 16 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 6 PY 1999 VL 103 IS 18 BP 3581 EP 3588 DI 10.1021/jp9900234 PG 8 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 196JA UT WOS:000080304200036 ER PT J AU Law, BE Baldocchi, DD Anthoni, PM AF Law, BE Baldocchi, DD Anthoni, PM TI Below-canopy and soil CO2 fluxes in a ponderosa pine forest SO AGRICULTURAL AND FOREST METEOROLOGY LA English DT Article DE carbon dioxide; ecophysiology; soil CO2 fluxes; eddy covariance; pine forests; Pinus ponderosa ID CARBON-DIOXIDE TRANSPORT; MIXED HARDWOOD FOREST; LITTER DECOMPOSITION; EDDY COVARIANCE; WATER-VAPOR; RESPIRATION; TEMPERATURE; ECOSYSTEMS; CHAMBER; EFFLUX AB Below-canopy eddy covariance measurements of CO2 flux (F-cb) and soil surface CO2 flux measurements (F-s) were made seasonally in a ponderosa pine forest in central Oregon in 1996 and 1997. The forest ecosystem has a very open canopy, and it is subject to drought and high vapor pressure deficits in summer. Below-canopy flux measurements in March, May, and August 1997 showed increasing effluxes from the forest floor as soils warmed. In July 1996, daytime F-cb measurements appeared to have been influenced by photosynthetic uptake of CO2 by ground vegetation. We did not see a similar diurnal trend in F-cb data in August 1997, probably because photosynthesis may have decreased with senescence of similar to 1/3 of the pine canopy and the herbaceous species. On 4 days in August 1997, the mean nocturnal F-s (2.6 +/- 0.08 mu mol m(-2) s(-1)) was lower than nocturnal F-cb (3.5 +/- 0.28 mu mol m(-2) s(-1)) by 26%, and daytime F-s was lower than nocturnal F-cb by 18%, possibly because F-cb includes respiration by understory and the lower portions of trees. The mean nocturnal NEE calculated from above-canopy flux and storage in the canopy airspace (F-ca + F-stor) at this time was 2.8 +/- 0.40 mu mol m(-2) s(-1), 23% lower than ecosystem respiration calculated from chamber measurements on soils, wood, and foliage. The largest difference was observed on a more a turbulent night (u* = 0.30 m s(-1)) when F-ca + F-stor was even significantly less than F-cb and F-s. Our hypothesis is that under calm conditions (e.g. u*<0.15 m s(-1) as observed on three of the nights), F-ca is negligible and has no impact on the CO2 budget. Under weak wind conditions (e.g. u* = 0.30 m s(-1)), F-ca begins to become significant and fluxes missed by the above-canopy eddy correlation system degrade the CO2 budget. Under windy conditions, the above-canopy eddy correlation measurement is a good approximation and the CO2 budget improves again. Below-canopy flux measurements provided useful temporal information for understanding seasonal differences in diel patterns, while the chambers allowed us to characterize spatial variation in CO2 fluxes. It is important to measure below-canopy fluxes along with above-canopy fluxes throughout the year to understand CO2 exchange components and annual contributions to the carbon budget of open canopy forest systems. (C) 1999 Elsevier Science B.V. All rights reserved. C1 Oregon State Univ, Dept Forest Sci, Corvallis, OR 97331 USA. NOAA, Atmospher Turbulence & Diffus Div, Oak Ridge, TN 37831 USA. Oregon State Univ, Coll Ocean & Atmospher Sci, Corvallis, OR 97331 USA. RP Law, BE (reprint author), Oregon State Univ, Dept Forest Sci, Peavy Hall 154, Corvallis, OR 97331 USA. RI Baldocchi, Dennis/A-1625-2009; OI Baldocchi, Dennis/0000-0003-3496-4919; Law, Beverly/0000-0002-1605-1203 NR 52 TC 110 Z9 120 U1 2 U2 19 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 3 PY 1999 VL 94 IS 3-4 BP 171 EP 188 DI 10.1016/S0168-1923(99)00019-2 PG 18 WC Agronomy; Forestry; Meteorology & Atmospheric Sciences SC Agriculture; Forestry; Meteorology & Atmospheric Sciences GA 194RD UT WOS:000080206600002 ER PT J AU Thomson, R Levine, LE Long, GG AF Thomson, R Levine, LE Long, GG TI Small-angle scattering by dislocations SO ACTA CRYSTALLOGRAPHICA SECTION A LA English DT Article ID X-RAY-SCATTERING; CRYSTALS; DEFORMATION; TENSILE AB It is shown that the small-angle scattering of X-rays or neutrons by dislocations within a deformed metal, which are partially ordered into wall-like structures, is characterized by several factors. Principally these are associated with: (i) a single dislocation or dipole; (ii) the dislocation configuration in the plane of the wall; and (iii) the distribution of dislocations across the wall thickness. With the assumption of isotropic elasticity, small-angle scattering will be sensitive only to the edge components of the dislocations. The scattered intensity is dominated by scattering from dislocations that lie perpendicular to the scattering vector, q, and reaches a maximum when q is normal to the slip plane of these dislocations. Above a particular \q\, the scattered intensity is sensitive only to the total edge dislocation content of the scattering dislocations (i.e, scattering is incoherent), while, below this value, the scattering is dominated by how the dislocations are distributed in walls. For walls normal to their slip planes, the configuration factor will reflect the dislocation distribution in the plane of the wall, while, for walls parallel to their slip planes, the distribution in the thickness direction will be visible. Therefore, even though a deformed material is composed of complicated dislocation structures, only those segments conforming to these rather strict prescriptions will be singled out for scattering, and, by adjusting the beam/slip system geometry, many parameters of the microstructure can be determined experimentally. C1 NIST, Gaithersburg, MD 20899 USA. RP Thomson, R (reprint author), NIST, Gaithersburg, MD 20899 USA. NR 21 TC 13 Z9 13 U1 1 U2 3 PU MUNKSGAARD INT PUBL LTD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0108-7673 J9 ACTA CRYSTALLOGR A JI Acta Crystallogr. Sect. A PD MAY 1 PY 1999 VL 55 BP 433 EP 447 DI 10.1107/S010876739801071X PN 3 PG 15 WC Chemistry, Multidisciplinary; Crystallography SC Chemistry; Crystallography GA 198AL UT WOS:000080399500004 ER PT J AU McKeown, DA Bell, MI Etz, ES AF McKeown, DA Bell, MI Etz, ES TI Raman spectra and vibrational analysis of the trioctahedral mica phlogopite SO AMERICAN MINERALOGIST LA English DT Article ID 4-MEMBERED SILICATE RINGS; BENITOITE BATISI3O9; GLASS STRUCTURE AB Raman spectra were measured and normal mode calculations were performed for phlogopite. Calculated fundamental mode frequencies were fit to observed frequencies assigned to features in the two polarized Raman spectra collected, so that unambiguous assignment of eigenmodes could be made to nearly all Raman spectral features. Average force constant values determined for Si-O and O-Si-O environments as well as for the non-silicate environments in cyclosilicates and gillespite provided an excellent starting point for the phlogopite calculations that quickly converged to a best fit of theoretical mode frequencies to the observed Raman fundamental mode frequencies. Final values of the force constants for T-O stretch and O-T-O bend are within the range of force constant values determined for Si-O and O-Si-O environments in cyclosilicates and gillespite. The force constant similarities extend to the K-O, M(1,2)-O bond stretch and M(1,2)-O-T bond bend environments. Raman-active modes at frequencies greater than 850 cm(-1) are localized intra-sheet modes dominated by T-O stretch and O-T-O bend motions. Raman-active modes between 350 and 850 cm(-1) are dominated by mixtures of internal sheer modes with displacements from the M2 sites. Raman-active lattice modes are calculated at frequencies less than 350 cm-l. Calculated frequencies for the IR-active A(u) and B-u, modes generally fall within the frequency ranges of broad bands in the IR spectra for phlogopite presented elsewhere. Eigenmodes calculated fur phlogopite are generally unique to that mica structure and differ from those determined fur the cyclosilicates and gillespite. The few eigenmodes calculated for phlogopite that resemble those calculated for the cyclosilicates are the most localized T-O stretch motions and are assigned to the highest frequency modes. C1 Catholic Univ Amer, Vitreous State Lab, Washington, DC 20064 USA. USN, Res Lab, Dynam Solids Branch, Washington, DC 20375 USA. Natl Inst Stand & Technol, Surface Microanal Sci Div, Gaithersburg, MD 20899 USA. RP McKeown, DA (reprint author), Catholic Univ Amer, Vitreous State Lab, 320 Michigan Ave NE, Washington, DC 20064 USA. NR 13 TC 35 Z9 35 U1 1 U2 6 PU MINERALOGICAL SOC AMER PI WASHINGTON PA 1015 EIGHTEENTH ST, NW SUITE 601, WASHINGTON, DC 20036 USA SN 0003-004X J9 AM MINERAL JI Am. Miner. PD MAY-JUN PY 1999 VL 84 IS 5-6 BP 970 EP 976 PG 7 WC Geochemistry & Geophysics; Mineralogy SC Geochemistry & Geophysics; Mineralogy GA 196HT UT WOS:000080303500034 ER PT J AU Margolis, SA AF Margolis, SA TI Source of the difference between the measurement of water in hydrocarbons as determined by the volumetric and coulometric Karl Fischer methods SO ANALYTICAL CHEMISTRY LA English DT Article AB The disparity between the volumetric and coulometric Karl Fischer methods for the measurement of water in hydrocarbons and hydrocarbon mixtures (oils) has been resolved. The amount of water detected by the volumetric method when the titration vessel solution is homogeneous is higher than that measured coulometrically or volumetrically when the titration vessel solution is heterogeneous. Water in oil that is not measured by the coulometric method when the oil is incompletely dissolved has been shown to reside in the oil phase of the heterogeneous (multiphasic) coulometric vessel suspension. Water that is not measured volumetrically under relatively low chloroform concentrations after the point of transition to a heterogeneous titration vessel solution is reached also appears to reside in the nonaqueous phase of the titration vessel solution. It appears that this water is retained in the hydrocarbon phase in a manner such that it is completely inaccessible to the volumetric or coulometric Karl Fischer reagents. C1 NIST, Div Analyt Chem, Gaithersburg, MD 20899 USA. RP Margolis, SA (reprint author), NIST, Div Analyt Chem, Gaithersburg, MD 20899 USA. NR 8 TC 14 Z9 15 U1 0 U2 4 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0003-2700 J9 ANAL CHEM JI Anal. Chem. PD MAY 1 PY 1999 VL 71 IS 9 BP 1728 EP 1732 DI 10.1021/ac981137z PG 5 WC Chemistry, Analytical SC Chemistry GA 192QP UT WOS:000080090700025 PM 21662813 ER PT J AU Duewer, DL Kline, MC Sharpless, KE Thomas, JB Gary, KT AF Duewer, DL Kline, MC Sharpless, KE Thomas, JB Gary, KT TI Micronutrients measurement quality assurance program: Helping participants use interlaboratory comparison exercise results to improve their long-term measurement performance SO ANALYTICAL CHEMISTRY LA English DT Article ID NOMENCLATURE AB Over the past decade, the Micronutrients Measurement Quality Assurance Program (M(2)QAP) at the National Institute of Standards and Technology (NIST) has administered nearly 40 interlaboratory comparison exercises devoted to fat-soluble vitamin-related analytes in human serum, While M(2)QAP studies have been used to help certify reference materials and to document the performance of analytical systems, the primary focus of the M(2)QAP has been, and remains, the improvement of amongparticipant measurement comparability for target analytes. Recent analysis of historical measurement performance indicated the most efficient mechanism for further improving measurement comparability among participants is the improvement of long-term (months to years) comparability within each laboratory. The summary reports for the M(2)QAP studies are being redesigned to provide more chemist-friendly analyses of participant performance, dissecting systematic and random components of measurement incomparability as functions of analyte level and time. This report documents the semantic and graphical tools developed to help interlaboratory-comparison-exercise participants interpret their own measurement performance. C1 Natl Inst Stand & Technol, Chem Sci & Technol Lab, Gaithersburg, MD 20899 USA. Ctr Dis Control & Prevent, Nutr Biochem Branch, Atlanta, GA 30341 USA. RP Duewer, DL (reprint author), Natl Inst Stand & Technol, Chem Sci & Technol Lab, Gaithersburg, MD 20899 USA. RI Duewer, David/B-7410-2008; OI Sharpless, Katherine/0000-0001-6569-198X NR 20 TC 14 Z9 14 U1 2 U2 4 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0003-2700 J9 ANAL CHEM JI Anal. Chem. PD MAY 1 PY 1999 VL 71 IS 9 BP 1870 EP 1878 DI 10.1021/ac981074k PG 9 WC Chemistry, Analytical SC Chemistry GA 192QP UT WOS:000080090700045 PM 10330911 ER PT J AU Kalinowski, ST Hedrick, PW AF Kalinowski, Steven T. Hedrick, Philip W. TI Detecting inbreeding depression is difficult in captive endangered species SO ANIMAL CONSERVATION LA English DT Article AB During the past two decades, pedigree analysis has documented inbreeding depression in many captive populations. This and subsequent research has led to a recognition that inbreeding depression is a potentially important determinate of small population fitness, in both captivity and the wild. Modern captive-breeding programmes now universally avoid inbreeding. We use simulation to investigate how much traditional pedigree analysis will reveal about the effect of inbreeding in such populations. We find that pedigrees typical of breeding programmes designed to avoid inbreeding have low statistical power to detect inbreeding depression. C1 [Kalinowski, Steven T.; Hedrick, Philip W.] Arizona State Univ, Dept Biol, Tempe, AZ 85287 USA. RP Kalinowski, ST (reprint author), NOAA, Natl Marine Fisheries Serv, Conservat Biol Div, Seattle, WA 98112 USA. EM Steven.Kalinowski@asu.edu FU Arizona Heritage Fund; U. S. Fish and Wildlife Service FX We thank Phil Miller for discussion during the development of these ideas and two anonymous reviewers for useful comments. This work was partially supported by the Arizona Heritage Fund and the U. S. Fish and Wildlife Service. NR 16 TC 19 Z9 19 U1 0 U2 4 PU BLACKWELL PUBLISHING PI OXFORD PA 9600 GARSINGTON RD, OXFORD OX4 2DQ, OXON, ENGLAND SN 1367-9430 J9 ANIM CONSERV JI Anim. Conserv. PD MAY PY 1999 VL 2 IS 2 BP 131 EP 136 DI 10.1111/j.1469-1795.1999.tb00058.x PG 6 WC Biodiversity Conservation; Ecology SC Biodiversity & Conservation; Environmental Sciences & Ecology GA V71EH UT WOS:000204810700007 ER PT J AU Kraut, S Nuttall, N Anderson, DZ AF Kraut, S Nuttall, N Anderson, DZ TI Photorefractive two-beam coupling equations with multiple spatial-temporal features: an SVD approach SO APPLIED PHYSICS B-LASERS AND OPTICS LA English DT Article AB We analyze the evolution of multi-feature two-beam coupling, wherein each beam contains several spatial-temporal features (spatial patterns modulated by different signals), using a one-dimensional plane wave model to describe the evolution of paired components. This general scenario is of interest for analyzing signal-processing applications of photorefractives, such as source-separation by orthogonalization of source-modulated spatial patterns. We use singular-value decomposition (SVD) to express each beam as a simple superposition of modes that are both temporally uncorrelated and spatially orthogonal. We find a solution that is a natural matrix generalization of the scalar solution for simple two-beam coupling, and a test for its validity: the two operators that give the spatial overlap associated with the temporal basis signals in the two beams must commute. Equivalently, this means that the same set of signals must be modulating the SVD modes in the two beams. Then the SVD modes are preserved in the two-beam coupling evolution, with only their amplitudes changing. C1 Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. Natl Inst Stand & Technol, Boulder, CO 80309 USA. RP Kraut, S (reprint author), Univ Colorado, Dept Elect & Comp Engn, CB 425, Boulder, CO 80309 USA. NR 14 TC 0 Z9 0 U1 0 U2 1 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 MAY PY 1999 VL 68 IS 5 BP 937 EP 945 DI 10.1007/s003400050727 PG 9 WC Optics; Physics, Applied SC Optics; Physics GA 194AV UT WOS:000080170700027 ER PT J AU Colle, R AF Colle, R TI Chemical digestion and radionuclidic assay of TiNi-encapsulated P-32 intravascular brachytherapy sources SO APPLIED RADIATION AND ISOTOPES LA English DT Article ID LIQUID SCINTILLATION SPECTROMETRY; COCKTAIL MASS VOLUME; RADIOACTIVITY MEASUREMENTS; EMITTING RADIONUCLIDES; H2O FRACTION; H-3; STANDARDIZATION; EFFICIENCY; PO-209; NI-63 AB A very quantitative, destructive assay procedure was devised for accurately measuring the P-32 activity content of TiNi-encapsulated intravascular brachytherapy sources and was applied to four different sources (termed 'seeds') which were developed and provided by Guidant Intravascular Intervention (formerly NeoCardia). These seeds are intended for use in the prophylactic treatment of restenosis following balloon angioplasty in heart-disease patients. The assays involved the dissolution of the TiNi jacket, extraction of the activity from the internal P-32-containing source material, quantitative solution transfers, and a gravimetrically-based dilution; followed by liquid scintillation (LS) spectrometry of the resulting master solution with H-3-standard efficiency tracing using composition-matched LS cocktails, The LS spectrometry utilized a previously-developed method for resolving the always-present P-33 impurity. The protocol included provisions for accounting for all possible losses of P-32 in the digestion procedure (based on radiochemical tracing experiments), for any unrecovered activity in the remaining source material, and for any residual activity in the solution-transfer and containing vessels. Sections of the TiNi jackets adjacent to the cutoff active seed portions were also assayed for any contained activity. Such destructive assays were required for relating measurements of the absorbed dose spatial distribution for the seeds to theoretic dose modelling and for establishing calibration factors for subsequent non-destructive radionuclidic measurements on the seeds. Published by Elsevier Science Ltd. C1 NIST, Phys Lab, Gaithersburg, MD 20899 USA. RP Colle, R (reprint author), NIST, Phys Lab, Gaithersburg, MD 20899 USA. EM rcolle@nist.gov NR 40 TC 16 Z9 17 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 1999 VL 50 IS 5 BP 811 EP 833 DI 10.1016/S0969-8043(98)00167-5 PG 23 WC Chemistry, Inorganic & Nuclear; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging SC Chemistry; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging GA 180KG UT WOS:000079384500001 PM 10214703 ER PT J AU Colle, R Zimmerman, BE Soares, CG Coursey, BM AF Colle, R Zimmerman, BE Soares, CG Coursey, BM TI Determination of a calibration factor for the nondestructive assay of Guidant P-32 brachytherapy sources SO APPLIED RADIATION AND ISOTOPES LA English DT Article ID LIQUID SCINTILLATION SPECTROMETRY; EFFICIENCY; VOLUME AB A calibration factor ('dial setting') for the nondestructive assay of Guidant TiNi-encapsulated P-32 intravascular brachytherapy wire sources has been determined for measurements with the Capintec CRC-12 (sic. 'dose calibrator') ionization chamber. The calibration factor was derived from ionization current measurements with the CRC-12 followed by very quantitative, destructive assays of the 32P content in two sources. Published by Elsevier Science Ltd. C1 NIST, Phys Lab, Gaithersburg, MD 20899 USA. RP Colle, R (reprint author), NIST, Phys Lab, Gaithersburg, MD 20899 USA. NR 12 TC 10 Z9 10 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0969-8043 J9 APPL RADIAT ISOTOPES JI Appl. Radiat. Isot. PD MAY PY 1999 VL 50 IS 5 BP 835 EP 841 DI 10.1016/S0969-8043(98)00166-3 PG 7 WC Chemistry, Inorganic & Nuclear; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging SC Chemistry; Nuclear Science & Technology; Radiology, Nuclear Medicine & Medical Imaging GA 180KG UT WOS:000079384500002 PM 10214704 ER PT J AU Witteborn, FC Cohen, M Bregman, JD Wooden, DH Heere, K Shirley, EL AF Witteborn, FC Cohen, M Bregman, JD Wooden, DH Heere, K Shirley, EL TI Spectral irradiance calibration in the infrared. XI. Comparison of alpha Bootis and 1 Ceres with a laboratory standard SO ASTRONOMICAL JOURNAL LA English DT Article DE infrared radiation; minor planets, asteroids; stars : individual (alpha Bootis); techniques : spectroscopic ID SPECTROSCOPY; ASTEROIDS; VESTA AB Infrared spectra of two celestial objects frequently used as flux standards are calibrated against an absolute laboratory flux standard at a spectral resolving power of 100 to 200. The spectrum of the K1.5 III star alpha Boo is measured from 3 to 30 mu m, and that of the C-type asteroid 1 Ceres from 5 to 30 mu m. While these "standard" spectra do not have the apparent precision of those based on calculated models, they do not require the assumptions involved in theoretical models of stars and asteroids. Specifically, they provide a model-independent means of calibrating celestial flux in the spectral range from 12 to 30 mu m, where accurate absolute photometry is not available. The agreement found between the spectral shapes of alpha Boo and Ceres based on laboratory standards and those based on observed ratios to alpha CMa (Sirius) and alpha Lyr (Vega), flux-calibrated by theoretical modeling of these hot stars, strengthens our confidence in the applicability of the stellar models as primary irradiance standards. C1 NASA, Ames Res Ctr, SETI Inst, Moffett Field, CA 94035 USA. NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA. Vanguard Res Inc, Scotts Valley, CA 95066 USA. Univ Calif Berkeley, Radio Astron Lab, Berkeley, CA 94720 USA. Natl Inst Stand & Technol, Opt Technol Div, Gaithersburg, MD 20899 USA. RP Witteborn, FC (reprint author), NASA, Ames Res Ctr, SETI Inst, Mail Stop 245-6, Moffett Field, CA 94035 USA. NR 17 TC 25 Z9 25 U1 1 U2 3 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 1999 VL 117 IS 5 BP 2552 EP 2560 DI 10.1086/300850 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 201XB UT WOS:000080621200040 ER PT J AU Steel, AB Herne, TM Tarlov, MJ AF Steel, AB Herne, TM Tarlov, MJ TI Electrostatic interactions of redox cations with surface-immobilized and solution DNA SO BIOCONJUGATE CHEMISTRY LA English DT Article ID COMPLEXES; PROBES; GOLD; ELECTRODE; HYBRIDIZATION; INTERCALATION; VOLTAMMETRY; BIOSENSOR AB Association constants for ruthenium(III) hexaamine and cobalt(III) tris(2,2'-bipyridine) with solution and surface-immobilized DNA were determined. The interaction of the cationic redox molecules with calf thymus DNA was monitored via normal pulse voltammetry with analysis of the mass-transfer limited current assuming a discrete binding-site model. Single-stranded DNA was immobilized on gold via self-assembly of a 5' hexanethiol linker. Double-stranded surface-immobilized DNA was produced by hybridization of a complementary target to surface-immobilized single strands. The interaction between the metal complexes and surface-immobilized DNA was determined using chronocoulometry to construct adsorption isotherms. The measured binding constants for the cationic redox molecules with solution, surface-immobilized single-stranded, and double-stranded DNA are well-correlated, even as a function of ionic strength. The agreement between the determined association constants for the surface-immobilized and solution DNA indicates the potential utility of DNA-derivatized electrodes for examination of small molecule interactions with nucleic acids. C1 NIST, Proc Sensing Grp, Gaithersburg, MD 20899 USA. RP Tarlov, MJ (reprint author), Gene Log Inc, 708 Quince Orchard Rd, Gaithersburg, MD 20878 USA. NR 25 TC 78 Z9 78 U1 2 U2 33 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1043-1802 J9 BIOCONJUGATE CHEM JI Bioconjugate Chem. PD MAY-JUN PY 1999 VL 10 IS 3 BP 419 EP 423 DI 10.1021/bc980115g PG 5 WC Biochemical Research Methods; Biochemistry & Molecular Biology; Chemistry, Multidisciplinary; Chemistry, Organic SC Biochemistry & Molecular Biology; Chemistry GA 200RD UT WOS:000080553100015 PM 10346873 ER PT J AU Heinisch, BV Fable, WA AF Heinisch, BV Fable, WA TI Movement of gag, Mycteroperca microlepis, in and from St. Andrew Bay, Florida SO BULLETIN OF MARINE SCIENCE LA English DT Article ID EASTERN GULF; SERRANIDAE; PISCES; MEXICO AB In this study, we investigated movements of gag, Mycteroperca microlepis, in a deep, high salinity embayment in the northeastern Gulf of Mexico from August 1994 through August 1996. Two hundred-fifty gag were captured in traps, tagged with internal anchor tags, and released into St. Andrew Bay, Florida. One hundred thirty-two (52.8%) tagged gag were recaptured by recreational anglers and by project personnel. Only 14.3% of gag moved from their release sites, with the distance moved averaging 2.38 km (east and southeast) within the bay. Six large gag (>500 mm total length) moved from 9 to 458 km out of the bay, presumably to recruit to offshore spawning stocks. Recaptured gag were free up to 645 d. Analysis of variance (ANOVA) of distance moved by gag revealed that days free was a significant effect in the model, but total length was not. C1 NOAA, Natl Marine Fisheries Serv, SEFSC, Panama City Lab, Panama City, FL 32408 USA. RP Heinisch, BV (reprint author), NOAA, Natl Marine Fisheries Serv, SEFSC, Panama City Lab, 3500 Delwood Beach Rd, Panama City, FL 32408 USA. NR 34 TC 10 Z9 11 U1 0 U2 1 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 1999 VL 64 IS 3 BP 501 EP 508 PG 8 WC Marine & Freshwater Biology; Oceanography SC Marine & Freshwater Biology; Oceanography GA 196YR UT WOS:000080338300008 ER PT J AU Lang, CI Shechtman, D Gonzalez, E AF Lang, CI Shechtman, D Gonzalez, E TI Friction and wear properties of quasi-periodic material coatings SO BULLETIN OF MATERIALS SCIENCE LA English DT Article DE friction; wear; quasi-periodic material ID AL-PD-MN; ALLOYS; NI AB Quasicrystalline (QC) materials are of interest not only because of their unique structure, but also because they exhibit unusual properties which are potentially useful in industrial applications. In the present study a range of aluminium-based QC alloys, in the form of plasma-sprayed coatings, has been produced and evaluated. For the first time the influence of heat treatment on the structure and properties of these coatings has been systematically investigated, Of the nine QC coatings investigated, those of the Al-Cu-Fe-Cr system and the Al-Pd-Mn system showed the most promising combination of good hardness with low coefficient of friction. C1 Technion Israel Inst Technol, Haifa, Israel. NIST, Gaithersburg, MD 20899 USA. Univ Cape Town, ZA-7700 Rondebosch, South Africa. RP Shechtman, D (reprint author), Technion Israel Inst Technol, Haifa, Israel. NR 9 TC 13 Z9 13 U1 1 U2 6 PU INDIAN ACADEMY SCIENCES PI BANGALORE PA P B 8005 C V RAMAN AVENUE, BANGALORE 560 080, INDIA SN 0250-4707 J9 B MATER SCI JI Bull. Mat. Sci. PD MAY PY 1999 VL 22 IS 3 BP 189 EP 192 DI 10.1007/BF02749918 PG 4 WC Materials Science, Multidisciplinary SC Materials Science GA 214EV UT WOS:000081316400007 ER PT J AU Lilly, DK AF Lilly, DK TI Comments on "From the tropics to the poles in forty days" SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Letter C1 Univ Oklahoma, Norman, OK 73019 USA. Natl Severe Storms Lab, Norman, OK 73069 USA. RP Lilly, DK (reprint author), Univ Oklahoma, Norman, OK 73019 USA. NR 4 TC 1 Z9 1 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 MAY PY 1999 VL 80 IS 5 BP 904 EP 905 PG 2 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 199LP UT WOS:000080483800007 ER PT J AU Bell, GD Halpert, MS Ropelewski, CF Kousky, VE Douglas, AV Schnell, RC Gelman, ME AF Bell, GD Halpert, MS Ropelewski, CF Kousky, VE Douglas, AV Schnell, RC Gelman, ME TI Climate assessment for 1998 SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article ID OUTGOING LONGWAVE RADIATION; SOUTH-AMERICAN SECTOR; NORTHERN-HEMISPHERE; OSCILLATION; PRECIPITATION; METHANE; TRENDS; MODEL; OZONE; ENSO AB The global climate during 1998 was affected by opposite extremes of the ENSO cycle, with one of the strongest Pacific warm episodes (El Nifio) in the historical record continuing during January-early May and Pacific cold episode (La Nina) conditions occurring from July-December. In bath periods, regional temperature, rainfall, and atmospheric circulation patterns across the Pacific Ocean and the Americas were generally consistent with those observed during past warm and cold episodes. Some of the most dramatic impacts from both episodes were observed in the Tropics, where anomalous convection was evident across the entire tropical Pacific and in most major monsoon regions of the world. Over the Americas, many of the El Nino- (La Nina-) related rainfall anomalies in the subtropical and extratropical latitudes were linked to an extension (retraction) of the jet streams and their attendant circulation features typically located over the subtropical latitudes of both the North Pacific and South Pacific. The regions most affected by excessive El Nino-related rainfall included 1) the eastern half of the tropical Pacific, including western Ecuador and northwestern Peru, which experienced significant flooding and mudslides; 2) southeastern South America, where substantial flooding was also observed; and 3) California and much of the central and southern United States during January-March, and the central United States during April-June. EI Nino-related rainfall deficits during 1998 included 1) Indonesia and portions of northern Australia; 2) the Amazon Basin, in association with a substantially weaker-than-normal South American monsoon circulation; 3) Mexico, which experienced extreme drought throughout the El Nino episode; and 4) the Gulf Coast states of the United States, which experienced extreme drought during April-June 1998. The El Nino also contributed to extreme warmth across North America during January-May. The primary La Nina-related precipitation anomalies included I) increased rainfall across Indonesia, and a nearly complete disappearance of rainfall across the east-central equatorial Pacific; 2) above-normal rains across northwestern, eastern, and northern Australia; 3) increased monsoon rains across central America and Mexico during October-December; and 4) dryness across equatorial eastern Africa. The active 1998 North Atlantic hurricane season featured 14 named storms (9 of which became hurricanes) and the strongest October hurricane (Mitch) in the historical record. In Honduras and Nicaragua extreme flooding and mudslides associated with Hurricane Mitch claimed more than 11 000 lives. During the peak of activity in August-September, the vertical wind sheer across the western Atlantic, along with both the structure and location of the African easterly jet, were typical of other active seasons. Other regional aspects of the short-term climate included 1) record rainfall and massive flooding in the Yangtze River Basin of central China during June-July; 2) a drier and shorter-than-normal 1997/98 rainy season in southern Africa; 3) above-normal rains across the northern section of the African Sahel during June-September 1998; and 4) a continuation of record warmth across Canada during June-November. Global annual mean surface temperatures during 1998 far land and marine areas were 0.56 degrees C above the 1961-90 base period means. This record warmth surpasses the previous highest anomaly of +0.43 degrees C set in 1997. Record warmth was also observed in the global Tropics and Northern Hemisphere extratropics during the year, and is partly linked to the strong El Nino conditions during January-early May. C1 Int Res Inst Climate Predict, Palisades, NY USA. Creighton Univ, Omaha, NE 68178 USA. NOAA, Climate Monitoring & Diagnost Lab, Boulder, CO 80303 USA. RP Halpert, MS (reprint author), NOAA, NCEP, Climate Predict Ctr, NWS, W-NP52,NSC,Rm 605,5200 Auth Rd, Camp Springs, MD 20746 USA. NR 34 TC 68 Z9 70 U1 2 U2 15 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0003-0007 J9 B AM METEOROL SOC JI Bull. Amer. Meteorol. Soc. PD MAY PY 1999 VL 80 IS 5 BP S1 EP S48 PG 48 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 199LP UT WOS:000080483800014 ER PT J AU Rocha-Olivares, A Vetter, RD AF Rocha-Olivares, A Vetter, RD TI Effects of oceanographic circulation on the gene flow, genetic structure, and phylogeography of the rosethorn rockfish (Sebastes helvomaculatus) SO CANADIAN JOURNAL OF FISHERIES AND AQUATIC SCIENCES LA English DT Article ID MITOCHONDRIAL-DNA; ANIMAL POPULATIONS; CONTROL REGION; POLYMORPHISM; EVOLUTION; CONSERVATION; FREQUENCIES; CALIFORNIA; SEQUENCES; ALLELES AB The genetic structure and phylogeography of 88 rosethorn rockfish (Sebastes helvomaculatus) from five localities (California, Oregon, British Columbia, and two in the Gulf of Alaska) were analyzed using DNA sequences from the mitochondrial control region. High levels of genetic diversity (h > 85%) and significant population genetic structure (F(ST) = 0.13, P < 0.001; AMOVA Phi(ST) = 0.15, P << 0.001) were found. A significant genetic break was detected (Phi(CT) = 0.22, P << 0.001) coinciding with the transition zone between the Oregonian and Aleutian zoogeographic provinces and consistent with retention and dispersal mechanisms associated with the oceanographic circulation of the region. A correlation between geographic distance and population genetic distance supported the hypothesis of gene flow dominated by pelagic-phase dispersal. Oregonian province populations had higher haplotype diversity, with >70% of the individuals representing a recent lineage absent in the Aleutian province. This suggests a limited northward dispersal across the zoogeographic boundary. The phylogeographic structure may be due to a founder effect in the Aleutian province or an ocean circulation driven pseudo-vicariance. These results demonstrate that organisms with protracted pelagic-phase stages and high dispersal capability can exhibit population genetic structure that reflects their historical demography and present dispersal patterns. C1 Univ Calif San Diego, Scripps Inst Oceanog, La Jolla, CA 92093 USA. Natl Ocean & Atmospher Adm, SW Fisheries Sci Ctr, La Jolla, CA 92038 USA. RP Rocha-Olivares, A (reprint author), Louisiana State Univ, Dept Sci Biol, 508 Life Sci Bldg, Baton Rouge, LA 70803 USA. EM arocha@1su.edu RI Rocha-Olivares, Axayacatl/A-9832-2008 OI Rocha-Olivares, Axayacatl/0000-0002-2700-9086 NR 37 TC 73 Z9 74 U1 0 U2 2 PU CANADIAN SCIENCE PUBLISHING, NRC RESEARCH PRESS PI OTTAWA PA 1200 MONTREAL ROAD, BUILDING M-55, OTTAWA, ON K1A 0R6, CANADA SN 0706-652X J9 CAN J FISH AQUAT SCI JI Can. J. Fish. Aquat. Sci. PD MAY PY 1999 VL 56 IS 5 BP 803 EP 813 DI 10.1139/cjfas-56-5-803 PG 11 WC Fisheries; Marine & Freshwater Biology SC Fisheries; Marine & Freshwater Biology GA 212UG UT WOS:000081235400008 ER PT J AU Berejikian, BA Smith, RJF Tezak, EP Schroder, SL Knudsen, CM AF Berejikian, BA Smith, RJF Tezak, EP Schroder, SL Knudsen, CM TI Chemical alarm signals and complex hatchery rearing habitats affect antipredator behavior and survival of chinook salmon (Oncorhynchus tshawytscha) juveniles SO CANADIAN JOURNAL OF FISHERIES AND AQUATIC SCIENCES LA English DT Article ID FATHEAD MINNOWS; COHO SALMON; PIMEPHALES-PROMELAS; NORTHERN PIKE; ESOX-LUCIUS; PREDATOR RECOGNITION; ACQUIRED RECOGNITION; TROUT; MYKISS; STEELHEAD AB The present study examined the effects of chemical antipredator conditioning on antipredator behavior and the relative effects of antipredator conditioning and seminatural rearing environments on postrelease survival of chinook salmon (Onocrhynchus tshawytscha). Hatchery-reared juvenile chinook salmon were exposed to extracts from conspecific tissue or to comparable stimuli from green swordtail (Xiphophorus helleri). These "injured fish" stimuli were paired with water that contained the odour of predatory cutthroat trout (Oncorhynchus clarki). Chinook salmon receiving conspecific stimuli showed higher levels of several antipredator behaviors compared with chinook salmon receiving green swordtail extracts. When the two groups of chinook salmon were tested 2 days later with cutthroat trout stimulus alone, the chinook salmon that had originally received injured conspecific stimuli paired with cutthroat trout odour spent more time motionless than chinook salmon that had received green swordtail stimuli and cutthroat trout odour. In another experiment, complex rearing treatments had a negative effect on instream survival (contrary to previous studies) that was compensated for by the application of the chinook salmon extract and cutthroat trout odour prior to release. Chinook salmon, like rainbow trout (Oncorhynchus mykiss), show antipredator behavior in response to chemical stimuli from injured conspecifics and learn predator recognition when such stimuli are paired with predator odour, improving survival in the wild. C1 Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, Manchester Marine Expt Stn, Manchester, WA 98353 USA. Univ Saskatchewan, Dept Biol, Saskatoon, SK S7N 5E2, Canada. Washington Dept Fish & Wildlife, Olympia, WA 98501 USA. RP Berejikian, BA (reprint author), Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, Manchester Marine Expt Stn, POB 130, Manchester, WA 98353 USA. NR 30 TC 105 Z9 107 U1 2 U2 22 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 1999 VL 56 IS 5 BP 830 EP 838 DI 10.1139/cjfas-56-5-830 PG 9 WC Fisheries; Marine & Freshwater Biology SC Fisheries; Marine & Freshwater Biology GA 212UG UT WOS:000081235400011 ER PT J AU Liang, R Senturker, S Shi, XL Bal, W Dizdaroglu, M Kasprzak, KS AF Liang, R Senturker, S Shi, XL Bal, W Dizdaroglu, M Kasprzak, KS TI Effects of Ni(II) and Cu(II) on DNA interaction with the N-terminal sequence of human protamine P2: enhancement of binding and mediation of oxidative DNA strand scission and base damage SO CARCINOGENESIS LA English DT Article ID DILUTION MASS-SPECTROMETRY; QUANTITATIVE-DETERMINATION; HYDROGEN-PEROXIDE; NICKEL(II); COPPER(II); CHROMATIN; EXPOSURE; IONS; MICE; HP2 AB Epidemiological evidence suggests that certain paternal exposures to metals may increase the risk of cancer in the progeny. This effect may be associated with promutagenic damage to the sperm DNA, The latter is packed with protamines which might sequester carcinogenic metals and moderate the damage. Human protamine P2 has an amino acid motif at its N-terminus that can serve as a heavy metal trap, especially for Ni(II) and Cu(II), We have synthesized a pentadecapeptide modeling this motif, Arg-Thr-His-Gly-Gln-Ser-His-Tyr-Arg-Arg-His-Cys-Ser-Arg-amide (HP2(1-15)) and described its complexes with Ni(II) and Cu(II), including their capacity to mediate oxidative DNA degradation [Bal et al, (1997) Chern. Res. Toxicol,, 10, 906-914 and 915-921], In the present study, effects of HP21-15 On NI(II)- and Cu(II)-mediated DNA oxidation by H(2)O(2) at pH 7.4 were investigated in more detail using the circular plasmid pUC19 DNA as a target, and the single/double-strand breaks and production of oxidized DNA bases, as end points. Ni(II) alone was found to promote oxidative DNA strand scission (mostly single strand breaks) and base damage, while Cu(LI) alone produced the same effects, but to a much greater extent. Both metals were relatively more damaging to the pyrimidine bases than to purine bases. HP2(1-15) fended to increase the Ni(H)/H(2)O(2)-induced DNA breakage. In sharp contrast, the destruction of DNA strands by Cu(II)/H(2)O(2) was almost completely prevented by HP2(1-15). The effect of HP21-15 On the oxidative DNA base damage varied from a limited enhancement (5-hydroxyhydantoin and thymine glycol) to slight suppression (5-hydroxycytosine, 5-hydroxyuracil, 8-oxoguanine, 8-oxoadenine, 2-hydroxyadenine, fapyguanine and fapyadenine) toward Ni(II)/H(2)O(2). HP2(1-15) strongly suppressed the oxidative activity of Cu(II)/H(2)O(2) in regard to all bases in DNA, Consistently with the above, the electron spin resonance/spin trap measurements revealed greater and more persistent generation of OH and O(2)(-).-like oxidants from H(2)O(2) by the Ni(II)-HP2(1-15) complex than by the Cu(II)-HP2(1-15) complex (no O(2)(-). was detected). Both complexes were also found to bind to DNA more strongly than HP2(1-15) alone. The results indicate that protamine P2 is capable of binding Ni(II) and Cu(II) and, in this way, attenuating the mediation of oxidative DNA damage by Cu(II), but not Ni(II), The effects found may be mechanistically involved in the reproductive toxicity and carcinogenicity of metals. C1 NCI, Comparat Carcinogenesis Lab, FCRDC, Frederick, MD 21702 USA. Natl Inst Stand & Technol, Chem Sci & Technol Lab, Gaithersburg, MD 20899 USA. NIOSH, Morgantown, WV 26505 USA. Wroclaw B Beirut Univ, Fac Chem, PL-50383 Wroclaw, Poland. RP Kasprzak, KS (reprint author), NCI, Comparat Carcinogenesis Lab, FCRDC, Frederick, MD 21702 USA. EM kasprkaz@mail.ncifcrf.gov RI Shi, Xianglin/B-8588-2012 NR 24 TC 59 Z9 61 U1 0 U2 6 PU OXFORD UNIV PRESS PI OXFORD PA GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND SN 0143-3334 J9 CARCINOGENESIS JI Carcinogenesis PD MAY PY 1999 VL 20 IS 5 BP 893 EP 898 DI 10.1093/carcin/20.5.893 PG 6 WC Oncology SC Oncology GA 191KY UT WOS:000080022700020 PM 10334208 ER PT J AU Karl, T AF Karl, T TI Weather and climate extremes: Changes,variations and a perspective from the insurance industry - Overview SO CLIMATIC CHANGE LA English DT Editorial Material C1 Natl Climat Data Ctr, NOAA, US Dept Commerce, Asheville, NC 28801 USA. RP Karl, T (reprint author), Natl Climat Data Ctr, NOAA, US Dept Commerce, 151 Patton Ave,Room 120, Asheville, NC 28801 USA. NR 0 TC 10 Z9 10 U1 0 U2 1 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0165-0009 J9 CLIMATIC CHANGE JI Clim. Change PD MAY PY 1999 VL 42 IS 1 BP 1 EP 2 DI 10.1023/A:1005432210032 PG 2 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA 236JQ UT WOS:000082596800001 ER PT J AU Trenberth, KE Owen, TW AF Trenberth, KE Owen, TW TI Workshop on Indices and Indicators for Climate Extremes, Asheville, NC, USA, 3-6 June 1997 - Breakout Group A: Storms SO CLIMATIC CHANGE LA English DT Article; Proceedings Paper CT Workshop on Indices and Indicators for Climate Extremes CY JUN 03-06, 1997 CL ASHEVILLE, NORTH CAROLINA SP CLIVAR, GCOS, WMO ID SEA-LEVEL PRESSURE; SOUTHERN-HEMISPHERE; INTERANNUAL VARIABILITY; OSCILLATION; CIRCULATION; PACIFIC; TRENDS; REGION AB The Working Group on Storms considered tropical cyclones, extratropical cyclones, thunderstorms and their associated winds and effects other than on temperatures and precipitation (which are dealt with by the other working groups) to be in their purview. Changes in observing systems and distribution of observers and people impacted by these phenomena confound trend analysis. In light of the difficulty of assembling homogeneous time series of small-scale phenomena such as thunderstorms, tornadoes and hail, and also the problems in wind measurements, the working group recommends that indices of wind be developed by taking advantage of long surface (or sea-level) pressure measurements and analyses. Because wind is a vector, two pairs of readings that are orthogonal are desirable. Instantaneous values over about 1000 km scales are desirable to generate statistics relevant to wind extremes. Recommendations are given on how the data might profitably be processed. Several other recommendations are made concerning data acquisition and processing, some of which apply to reanalysis of past data and some apply to future processing of data. Various "extremes indices" are also suggested. C1 Natl Ctr Atmospher Res, Boulder, CO 80307 USA. NOAA, Natl Climat Data Ctr, Asheville, NC 28801 USA. RP Trenberth, KE (reprint author), Natl Ctr Atmospher Res, POB 3000, Boulder, CO 80307 USA. RI Trenberth, Kevin/A-5683-2012 OI Trenberth, Kevin/0000-0002-1445-1000 NR 34 TC 12 Z9 12 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0165-0009 J9 CLIMATIC CHANGE JI Clim. Change PD MAY PY 1999 VL 42 IS 1 BP 9 EP 21 DI 10.1023/A:1005443610940 PG 13 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA 236JQ UT WOS:000082596800003 ER PT J AU Nicholls, N Murray, W AF Nicholls, N Murray, W TI Workshop on Indices and Indicators for Climate Extremes, Asheville, NC, USA, 3-6 June 1997 - Breakout Group B: Precipitation SO CLIMATIC CHANGE LA English DT Article; Proceedings Paper CT Workshop on Indices and Indicators for Climate Extremes CY JUN 03-06, 1997 CL ASHEVILLE, NORTH CAROLINA SP CLIVAR, GCOS, WMO AB A uniform, international reference system of precipitation indices would greatly facilitate assessment of changes in global precipitation patterns, intensities and extremes. However, national/regional differences in precipitation monitoring standards, data quality control procedures, and product development practices complicate efforts to develop such a system. This report represents the results of Working Group B's concerted effort to examine in detail the problems associated with the development of the needed indicators and the Group's recommendations to address the identified issues. The Group concluded that a successful strategy must define a minimum set of indices/indicators based on higher quality data that would represent a global base set. The Group identified a set of indices for this purpose. This base data set should be complemented where possible by countries/regions having the data sets and processing resources to do more. C1 Bur Meteorol Res Ctr, Melbourne, Vic, Australia. NOAA, Off Global Programs, Silver Spring, MD USA. RP Nicholls, N (reprint author), Bur Meteorol Res Ctr, Melbourne, Vic, Australia. RI Nicholls, Neville/A-1240-2008 NR 0 TC 64 Z9 66 U1 0 U2 4 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0165-0009 J9 CLIMATIC CHANGE JI Clim. Change PD MAY PY 1999 VL 42 IS 1 BP 23 EP 29 DI 10.1023/A:1005495627778 PG 7 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA 236JQ UT WOS:000082596800004 ER PT J AU Folland, CK Miller, C Bader, D Crowe, M Jones, P Plummer, N Richman, M Parker, DE Rogers, J Scholefield, P AF Folland, CK Miller, C Bader, D Crowe, M Jones, P Plummer, N Richman, M Parker, DE Rogers, J Scholefield, P TI Workshop on Indices and Indicators for Climate Extremes, Asheville, NC, USA, 3-6 June 1997 - Breakout Group C: Temperature indices for climate extremes SO CLIMATIC CHANGE LA English DT Article; Proceedings Paper CT Workshop on Indices and Indicators for Climate Extremes CY JUN 03-06, 1997 CL ASHEVILLE, NORTH CAROLINA SP CLIVAR, GCOS, WMO ID MINIMUM TEMPERATURE; TRENDS; VARIABILITY; INDEXES; MAXIMUM AB The "temperature" breakout group at the 1997 Asheville Workshop on Indicators and Indices for Climate Extremes reviewed and developed the rationale for a choice of temperature indices for monitoring changes in climate extremes, and the supporting data required. A set of basic and supplementary key indices was drawn up. The key indices are meant to be easy to interpret, be relevant to the practical concerns of policy makers and others in the public sector and provide potential inputs into the Third Assessment Review of the Intergovernmental Panel on Climate Change that is expected to report in 2001. The indices are expressed in various ways to facilitate spatial and temporal trend detection and impact analysis. There is flexibility in the number and the form of the indices identified and the choice for any particular application is subject to further analysis and prioritization. The success of this endeavor will depend on original work being done to further develop the indices and on the cooperation of organizations globally to provide the data necessary for the development and the implementation of the indices. This paper summarizes the group's recommendations. C1 Meteorol Off, Hadley Ctr, Bracknell RG12 2SY, Berks, England. NOAA,NESDIS,E EI, Silver Spring, MD 20910 USA. Pacific NW Natl Lab, Washington, DC 20024 USA. NOAA,NCDC, Asheville, NC 28801 USA. Univ E Anglia, Climat Res Unit, Norwich NR4 7TJ, Norfolk, England. Bur Meteorol, Natl Climat Ctr, Melbourne, Vic 3001, Australia. Univ Oklahoma, CIMMS, Norman, OK 73019 USA. Ohio State Univ, Dept Geog, Columbus, OH 43210 USA. WMO, World Climate Data & Monitoring Programme, Geneva 2, Switzerland. RP Folland, CK (reprint author), Meteorol Off, Hadley Ctr, Bracknell RG12 2SY, Berks, England. RI Jones, Philip/C-8718-2009; Bader, David/H-6189-2011; Folland, Chris/I-2524-2013 OI Jones, Philip/0000-0001-5032-5493; Bader, David/0000-0003-3210-339X; NR 22 TC 57 Z9 61 U1 0 U2 4 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0165-0009 J9 CLIMATIC CHANGE JI Clim. Change PD MAY PY 1999 VL 42 IS 1 BP 31 EP 43 DI 10.1023/A:1005447712757 PG 13 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA 236JQ UT WOS:000082596800005 ER PT J AU Landsea, CW Pielke, RA Mestas-Nunez, A Knaff, JA AF Landsea, CW Pielke, RA Mestas-Nunez, A Knaff, JA TI Atlantic basin hurricanes: Indices of climatic changes SO CLIMATIC CHANGE LA English DT Article ID TROPICAL CYCLONE ACTIVITY; SEA-SURFACE TEMPERATURE; SAHELIAN MONSOON RAINFALL; WEST-AFRICAN RAINFALL; UNITED-STATES; EL-NINO; SOUTHERN OSCILLATION; EQUATORIAL PACIFIC; STRONG ASSOCIATION; STORM FORMATION AB Accurate records of basinwide Atlantic and U.S. landfalling hurricanes extend back to the mid 1940s and the turn of the century respectively, as a result of aircraft reconnaissance and instrumented weather stations along the U.S. coasts. Such long-term records are not exceeded elsewhere in the tropics. The Atlantic hurricanes, U.S. landfalling hurricanes and U.S. normalized damage time series are examined for interannual trends and multidecadal variability. It is found that only weak linear trends can be ascribed to the hurricane activity and that multidecadal variability is more characteristic of the region. Various environmental factors including Caribbean sea level pressures and 200mb zonal winds, the stratospheric Quasi-Biennial Oscillation, the El Nino-Southern Oscillation, African West Sahel rainfall and Atlantic sea surface temperatures, are analyzed for interannual links to the Atlantic hurricane activity. All show significant, concurrent relationships to the frequency, intensity and duration of Atlantic hurricanes. Additionally, variations in the El Nino-Southern Oscillation are significantly linked to changes in U.S. tropical cyclone-caused damages. Finally much of the multidecadal hurricane activity can be linked to the Atlantic Multidecadal Made - an empirical orthogonal function pattern derived from a global sea surface temperature record. Such linkages may allow for prediction of Atlantic hurricane activity on a multidecadal basis. These results are placed into the context of climate change and natural hazards policy. C1 NOAA,AOML,Hurricane Res Div, Miami, FL 33149 USA. NCAR,Environm & Societal Impacts Grp, Boulder, CO 80307 USA. Univ Miami, CIMAS, Miami, FL 33149 USA. NOAA, Cooperat Inst Res Atmosphere, Ft Collins, CO 80523 USA. RP Landsea, CW (reprint author), NOAA,AOML,Hurricane Res Div, 4301 Rickenbacker Causeway, Miami, FL 33149 USA. RI Knaff, John /F-5599-2010; Mestas-Nunez, Alberto/A-1427-2012 OI Knaff, John /0000-0003-0427-1409; Mestas-Nunez, Alberto/0000-0002-3546-3668 NR 77 TC 203 Z9 209 U1 9 U2 35 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0165-0009 J9 CLIMATIC CHANGE JI Clim. Change PD MAY PY 1999 VL 42 IS 1 BP 89 EP 129 DI 10.1023/A:1005416332322 PG 41 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA 236JQ UT WOS:000082596800009 ER PT J AU Groisman, PY Karl, TR Easterling, DR Knight, RW Jamason, PF Hennessy, KJ Suppiah, R Page, CM Wibig, J Fortuniak, K Razuvaev, VN Douglas, A Forland, E Zhai, PM AF Groisman, PY Karl, TR Easterling, DR Knight, RW Jamason, PF Hennessy, KJ Suppiah, R Page, CM Wibig, J Fortuniak, K Razuvaev, VN Douglas, A Forland, E Zhai, PM TI Changes in the probability of heavy precipitation: Important indicators of climatic change SO CLIMATIC CHANGE LA English DT Article ID CONTINENTAL UNITED-STATES; EXTREME EVENTS; NORTH-AMERICA; TRENDS; TEMPERATURE; VARIABILITY; FREQUENCY; RAINFALL; CANADA; SIMULATION AB A simple statistical model of daily precipitation based on the gamma distribution is applied to summer (JJA in Northern Hemisphere, DJF in Southern Hemisphere) data from eight countries: Canada, the United States, Mexico, the former Soviet Union, China, Australia, Norway, and Poland. These constitute more than 40% of the global land mass, and more than 80% of the extratropical land area. It is shown that the shape parameter of this distribution remains relatively stable, while the scale parameter is most variable spatially and temporally. This implies that the changes in mean monthly precipitation totals tend to have the most influence on the heavy precipitation rates in these countries. Observations show that in each country under consideration (except China), mean summer precipitation has increased by at least 5% in the past century. In the USA, Norway, and Australia the frequency of summer precipitation events has also increased, but there is little evidence of such increases in any of the countries considered during the past fiffty years. A scenario is considered, whereby mean summer precipitation increases by 5% with no change in the number of days with precipitation or the shape parameter. When applied in the statistical model, the probability of daily precipitation exceeding 25.4 mm (1 inch) in northern countries (Canada, Norway, Russia, and Poland) or 50.8 mm (2 inches) in mid-latitude countries (the USA, Mexico, China, and Australia) increases by about 20% (nearly four times the increase in mean). The contribution of heavy rains (above these thresholds) to the total 5% increase of precipitation is disproportionally high (up to 50%), while heavy rain usually constitutes a significantly smaller fraction of the precipitation events and totals in extratropical regions (but up to 40% in the tropics, e.g., in southern Mexico). Scenarios with moderate changes in the number of days with precipitation coupled with changes in the scale parameter were also investigated and found to produce smaller increases in heavy rainfall but still support the above conclusions. These scenarios give changes in heavy rainfall which are comparable to those observed and are consistent with the greenhouse-gas-induced increases in heavy precipitation simulated by some climate models for the next century. In regions with adequate data coverage such as the eastern two-thirds of contiguous United States, Norway, eastern Australia, and the European part of the former USSR, the statistical model helps to explain the disproportionate high changes in heavy precipitation which have been observed. C1 US Natl Climat Data Ctr, Univ Corp Atmospher Res Visiting Scientist, Asheville, NC 28801 USA. US Natl Climat Data Ctr, Asheville, NC 28801 USA. CSIRO Atmospher Res, Aspendale, Vic 3195, Australia. Univ Lodz, Dept Meteorol & Climatol, PL-90568 Lodz, Poland. Res Inst Hydrometeorol Informat, Obninsk 601240, Russia. Creighton Univ, Dept Atmospher Sci, Omaha, NE 68178 USA. Norwegian Meteorol Inst, N-0313 Oslo, Norway. Natl Climate Ctr, Beijing 100081, Peoples R China. RP Groisman, PY (reprint author), US Natl Climat Data Ctr, Univ Corp Atmospher Res Visiting Scientist, 151 Patton Ave, Asheville, NC 28801 USA. RI Whetton, Penny/A-6885-2012; Hennessy, Kevin/B-6821-2015; Hennessy, Kevin/S-4123-2016 OI Hennessy, Kevin/0000-0003-2811-3296 NR 66 TC 360 Z9 436 U1 13 U2 110 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0165-0009 J9 CLIMATIC CHANGE JI Clim. Change PD MAY PY 1999 VL 42 IS 1 BP 243 EP 283 DI 10.1023/A:1005432803188 PG 41 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA 236JQ UT WOS:000082596800015 ER PT J AU Easterling, DR Diaz, HF Douglas, AV Hogg, WD Kunkel, KE Rogers, JC Wilkinson, JF AF Easterling, DR Diaz, HF Douglas, AV Hogg, WD Kunkel, KE Rogers, JC Wilkinson, JF TI Long-term observations for monitoring extremes in the Americas SO CLIMATIC CHANGE LA English DT Article ID UNITED-STATES; FLORIDA CITRUS; TEMPERATURE; PRECIPITATION; TRENDS; VARIABILITY; MAXIMUM; FREEZES; SERIES; CANADA AB In this paper we discuss data available from Argentina Mexico, the United States and Canada that are suitable for the analysis of extreme temperature and precipitation events. We also discuss some of the problems of homogeneity and quality control that can potentially affect the observation of extreme values. It is clear that even in countries like the United States and Canada that have a potentially rich source of climate data there are still problems in obtaining homogeneous data necessary to perform thorough studies of time varying changes in extreme events. These types of problems may be compounded if data are needed from countries that do not have a tradition of maintaining large climate archives or observing networks. We also provide two examples of analyses that can be performed with these types of data: (1) the development of climate extremes indices for Canada, and (2) analyses of freezing events for Florida and the effect on the citrus industry. The Canadian example provides a good basis for countries to take indices developed for one country or region and through minor modifications make the index relevant to their own needs. The analysis of freezing events in Florida is a timely example of how extreme events have both ecological and societal impact. C1 NOAA,NESDIS,Natl Climat Data Ctr, Asheville, NC 28801 USA. NOAA,ERL,Climate Diagnost Ctr, Boulder, CO USA. Creighton Univ, Dept Atmospher Sci, Omaha, NE USA. Atmospher Environm Serv, Climate Res Branch, Downsview, ON, Canada. Illinois State Water Survey, Midwestern Climate Ctr, Champaign, IL USA. Ohio State Univ, Dept Geog, Columbus, OH 43210 USA. Serv Meteorol Nacl, Buenos Aires, DF, Argentina. RP Easterling, DR (reprint author), NOAA,NESDIS,Natl Climat Data Ctr, Asheville, NC 28801 USA. RI Kunkel, Kenneth/C-7280-2015 OI Kunkel, Kenneth/0000-0001-6667-7047 NR 35 TC 24 Z9 24 U1 0 U2 5 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0165-0009 J9 CLIMATIC CHANGE JI Clim. Change PD MAY PY 1999 VL 42 IS 1 BP 285 EP 308 DI 10.1023/A:1005484820026 PG 24 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA 236JQ UT WOS:000082596800016 ER PT J AU Karl, TR Easterling, DR AF Karl, TR Easterling, DR TI Climate extremes: Selected review and future research directions SO CLIMATIC CHANGE LA English DT Article ID FLORIDA CITRUS; HEAT-WAVE; TEMPERATURE; TRENDS; EVENTS; VARIABILITY; PRECIPITATION; FREQUENCY AB Trends and multi-decadal variations of weather and climate extremes have only recently received attention from the climate community. Interest has stemmed from exponentially increasing economic losses related to climate and weather extremes, and apparent increases in deaths attributed to these events, suggesting that key decision makers need a better understanding of the potential uses of climate information. The need for data on climate extremes in disaster mitigation activities such as the International Decade for Natural Disaster Reduction also has provided another motivation for focus in this area. The losses cited above raise questions as to whether extreme weather events are actually increasing in frequency, whether society as a whole is becoming more vulnerable to extreme weather events, whether public perception has been unduly influenced by enhanced media attention, or some combination. Given these questions, of particular interest here is the extent to which we can document changes in climate and weather extremes. Attribution of ongoing trends to specific climate forcings, such as anthropogenic effects or other factors related to natural climate variability are still equivocal. For some areas and variables increases in the frequency of extreme events are apparent, while in other areas there are suggestions of declines in these events. A review of this information suggests that further understanding of the cause(s) of the apparent changes in climate and weather extremes is strongly dependent upon progress in our ability to monitor and detect these multi-decadal trends. Based on these analyses we show that this will likely require increased attention in the following areas: 1) The development of more effective international data exchange for high resolution historical climate and weather records, 2) Increased emphasis on rescuing data with appropriate resolution from deteriorating manuscripts and other non-electronic media, 3) A greater emphasis on removing inhomogeneities' in the instrumental record and ongoing weather monitoring programs (that provide much of our information about changes and variations of weather and climate extremes), 4) More effective use of space-based measurements and reanalysis products derived from models, 5) More robust monitoring of local extreme weather events such as tornadoes, hail, lightning, and wind, and 6) More effective means to integrate and communicate information about what we know and do not know about changes in climate extremes. Progress in each of these areas is reviewed in context with outstanding remaining challenges, and the benefits that can be expected if we meet these requirements. C1 NOAA,NESDIS,Natl Climat Data Ctr, Asheville, NC 28801 USA. RP NOAA,NESDIS,Natl Climat Data Ctr, Asheville, NC 28801 USA. NR 41 TC 106 Z9 116 U1 3 U2 57 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0165-0009 EI 1573-1480 J9 CLIMATIC CHANGE JI Clim. Change PD MAY PY 1999 VL 42 IS 1 BP 309 EP 325 DI 10.1023/A:1005436904097 PG 17 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA 236JQ UT WOS:000082596800017 ER PT J AU Dou, XK Testud, J Amayenc, P Black, R AF Dou, XK Testud, J Amayenc, P Black, R TI The parameterization of rain for a weather radar SO COMPTES RENDUS DE L ACADEMIE DES SCIENCES SERIE II FASCICULE A-SCIENCES DE LA TERRE ET DES PLANETES LA English DT Article DE drop size distribution; precipitation; rain radar ID SIZE DISTRIBUTIONS; ATTENUATION AB Quantitative measurement of rain is an important application of radar remote sensing. The variability of raindrop size distribution is one of the major error sources originating from natural rainfall properties. The study of an airborne microphysical data set from the TOGA/COARE experiment shows that the large dispersion seen in the relationships between integral rainfall parameters can be remarkably reduced when using relevant scaling by parameter N-0*, a function of the liquid water content W, and the med lan volume diameter D-0. The statistics of N-0* show the importance of considering different mean values for convective and stratiform rain, respectively. ((C) Academie des sciences/Elsevier, Paris.). C1 Ctr Etud Environm Terr & Planetaires, F-78140 Velizy Villacoublay, France. NOAA, Atlantic Oceanog & Meteorol Lab, Hurricane Res Div, Miami, FL 33149 USA. RP Ctr Etud Environm Terr & Planetaires, 10-12 Av Europe, F-78140 Velizy Villacoublay, France. EM testud@cetp.ipsl.fr RI Black, Robert/C-9617-2009; Dou, xiankang/M-9106-2013 OI Black, Robert/0000-0001-6938-125X; NR 12 TC 7 Z9 7 U1 0 U2 3 PU ELSEVIER FRANCE-EDITIONS SCIENTIFIQUES MEDICALES ELSEVIER PI PARIS PA 23 RUE LINOIS, 75724 PARIS, FRANCE SN 1251-8050 J9 CR ACAD SCI II A JI Comptes Rendus Acad. Sci. Ser II-A PD MAY PY 1999 VL 328 IS 9 BP 577 EP 582 DI 10.1016/S1251-8050(99)80153-0 PG 6 WC Geosciences, Multidisciplinary SC Geology GA 200KC UT WOS:000080538000002 ER PT J AU Sonnerup, RE Quay, PD Bullister, JL AF Sonnerup, RE Quay, PD Bullister, JL TI Thermocline ventilation and oxygen utilization rates in the subtropical North Pacific based on CFC distributions during WOCE SO DEEP-SEA RESEARCH PART I-OCEANOGRAPHIC RESEARCH PAPERS LA English DT Article ID SHALLOW SALINITY MINIMA; INTERMEDIATE WATER; OCEAN; CIRCULATION; SEA; CHLOROFLUOROMETHANES; RADIOCARBON; ATLANTIC; GYRE; CHLOROFLUOROCARBONS AB Thermocline ventilation rates for the subtropical North Pacific are determined using a 1-dimensional (meridional) along-isopycnal advective-diffusive model tuned to chlorofluorocarbon (CFC) concentrations measured along 152 degrees W in 1991 during WOCE P16. Mean southward advection rates in the subtropics range from 1.03 to 0.56 cm s(-1) between sigma(theta) = 25.5 and 26.6. Model-derived ventilation times for the subtropical gyre increase from about 10 to 27 years for that isopycnal range. Oxygen utilization rates (OURs) determined using the advective-diffusive model decrease with depth from 6.6 to 3.2 mu mol kg(-1) yr(-1) between sigma(theta) = 25.5 and 26.6, Extrapolation of the OUR versus depth trend to the base of the euphotic zone with the 1/Z power function of Martin et al. (1987) and integration from 500 to 100 m depth implies a carbon export rate from the overlying euphotic zone of 2.2 +/- 0.5 moles C m(-2) yr(-1) at 30 degrees N, 152 degrees W. Analysis of the WOCE radiocarbon and salinity distributions indicates that zonal and cross-isopycnal transport terms would have to be considered in modeling these tracers in the subtropical North Pacific. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Univ Washington, Sch Oceanog, Seattle, WA 98195 USA. NOAA, Pacific Marine Environm Lab, Seattle, WA 98115 USA. RP Sonnerup, RE (reprint author), Univ Washington, Sch Oceanog, Seattle, WA 98195 USA. NR 58 TC 41 Z9 42 U1 0 U2 4 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0967-0637 J9 DEEP-SEA RES PT I JI Deep-Sea Res. Part I-Oceanogr. Res. Pap. PD MAY PY 1999 VL 46 IS 5 BP 777 EP 805 DI 10.1016/S0967-0637(98)00092-2 PG 29 WC Oceanography SC Oceanography GA 189FL UT WOS:000079893800003 ER PT J AU Stansbury, JW Antonucci, JM AF Stansbury, JW Antonucci, JM TI Dimethacrylate monomers with varied fluorine contents and distributions SO DENTAL MATERIALS LA English DT Article DE fluorinated polymers; dimethacrylate monomers; resins AB Objectives: There are many unique properties associated with fluorinated polymers that make these materials attractive for use in the challenging oral environment. This study was devised to better define the influence of fluorine content and its structural distribution on properties of fluorinated resins and composites, especially with regard to their water-related and mechanical properties. Methods: A series of fluorinated dimethacrylate monomers was prepared by reaction of aromatic diepoxides with fluoroalcohols and subsequent conversion of the resulting diols to the methacrylates. Composites based on monomer systems comprised of the fluorinated monomers with 1,10-decamethylene dimethacrylate and reinforced with silanized quartz filler were evaluated for conversion, water contact angle, water sorption and diametral tensile strength. Results: By selection of reactants, fluorine was introduced as trifluoromethyl groups, extended fluoroalkyl pendant chains, or combinations of the two. Photopolymerization conversion among the experimental composites was generally equal to or greater than that of a conventional Bis-GMA/TEGDMA composite. While the water contact angles generally increased with fluorine content, no correlation was obtained between fluorine content and water sorption of the composites. The mechanical strength of the fluorinated composites showed a general decline with increasing fluorine content and consistent variations due to specific structural features. Significance: A versatile route to fluorinated dimethacrylates with diverse structural and fluorine distribution patterns is presented. Composites from these monomers are very hydrophobic but have relatively low mechanical strength. The monomers described can be considered as useful additives to moderate the water sorption of conventional resins. Howe, er, the results of this study point to specific fluorinated resin structures that an expected to provide a more optimal balance between hydrophobicity and mechanical strength that will improve the long-term performance of dental composites. Published by Elsevier Science Ltd. on behalf of the Academy of Dental Materials. C1 NIST, Div Polymers, Dent & Med Mat Grp, Gaithersburg, MD 20899 USA. RP Stansbury, JW (reprint author), NIST, Div Polymers, Dent & Med Mat Grp, 100 Bur Dr,Stop 8845, Gaithersburg, MD 20899 USA. FU NIDCR NIH HHS [Y1-DE-7006-0] NR 20 TC 45 Z9 46 U1 1 U2 4 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 MAY PY 1999 VL 15 IS 3 BP 166 EP 173 DI 10.1016/S0109-5641(99)00028-7 PG 8 WC Dentistry, Oral Surgery & Medicine; Materials Science, Biomaterials SC Dentistry, Oral Surgery & Medicine; Materials Science GA 216MM UT WOS:000081446500003 PM 10551079 ER PT J AU Gillette, DA Chen, WN AF Gillette, DA Chen, WN TI Size distributions of saltating grains: An important variable in the production of suspended particles SO EARTH SURFACE PROCESSES AND LANDFORMS LA English DT Article DE dust; emissions; sandblasting; saltation ID WIND AB Size distributions were obtained for airborne particles in the saltation layer for cases where the ratio of the vertical flux of suspended particles to the horizontal flux of particles of all sizes is known. The data can be used to test theories of emissions of suspended particles. All of our sampled erodible soils with textures of sand, loamy sand and loam had saltation-grain mean particle sizes in the range 117-160 mu m. Our clay soil had saltation mean particle sizes ranging from 560 to 584 mu m. In the light of these data, we interpret the results found previously as supporting sandblasting rather than direct aerodynamic entrainment. The data are consistent with sandblasting theories of Shao et al. and of Alfaro. Copyright (C) 1999 John Wiley & Sons, Ltd. C1 NOAA, Air Resources Lab, Atmospher Sci Modeling Div, Res Triangle Pk, NC 27711 USA. NOAA, Air Resources Lab, Natl Res Council, Res Triangle Pk, NC 27711 USA. RP Gillette, DA (reprint author), NOAA, Air Resources Lab, Atmospher Sci Modeling Div, Res Triangle Pk, NC 27711 USA. NR 14 TC 22 Z9 23 U1 0 U2 2 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX PO19 1UD, ENGLAND SN 0197-9337 J9 EARTH SURF PROC LAND JI Earth Surf. Process. Landf. PD MAY PY 1999 VL 24 IS 5 BP 449 EP 462 DI 10.1002/(SICI)1096-9837(199905)24:5<449::AID-ESP1>3.0.CO;2-E PG 14 WC Geography, Physical; Geosciences, Multidisciplinary SC Physical Geography; Geology GA 198JJ UT WOS:000080420100007 ER PT J AU Niemeyer, TC Gillette, DA Deluisi, JJ Kim, YJ Niemeyer, WF Ley, T Gill, TE Ono, D AF Niemeyer, TC Gillette, DA Deluisi, JJ Kim, YJ Niemeyer, WF Ley, T Gill, TE Ono, D TI Optical depth, size distribution and flux of dust from Owens Lake, California SO EARTH SURFACE PROCESSES AND LANDFORMS LA English DT Article DE dust; flux; emissions; optical depth; Owens Lake; CA ID SPECTRAL EXTINCTION; ATMOSPHERIC DUST; DRY LAKE; AEROSOLS; CALIBRATION; PARTICLES; RADIATION; CLIMATE; CLOUD; MASS AB A joint United States/Russian/French collaborative experiment was undertaken in March 1993 and March 1996. Projects LODE I and II (Lake Owens Dust Experiments) took place on the anthropogenically desertified playa (dry lakebed) and surrounding regions of Owens Lake, in east-central California. One of the five parts of Project LODE was to determine relationships between optical depth and flux of dust emitted from the dry lake. Project LODE II included subsequent dust plume measurements and size distributions obtained through April 1996, to further refine the flux measurements for distinct mineral aerosol source regions at Owens Lake. Size distributions of dust aerosol were determined and aerosol optical depths were calculated from sunphotometer solar extinction measurements taken downwind in plumes coming from the emissive areas of Owens Lake. This source was visually observed for 10 measured dust storms. The plume mass was calculated to be 1.5 x 10(9) g using ground-based measurements and greater than or equal to 1.6 x 10(9) g from satellite data. Project LODE II results were found to be consistent with LODE I results for the south end of the playa, but flux values were found to be reduced for the northeastern portion of the playa by comparison. Vertical flux values estimated by sunphotometry were found to be consistent with values estimated via a micrometeorological method. Copyright (C) 1999 John Wiley & Sons, Ltd. C1 NOAA, Air Resources Lab, Atmospher Sci Modelling Div, Res Triangle Pk, NC 27711 USA. NOAA, Air Resources Lab, Surface Radiat Res Branch, Boulder, CO 80303 USA. Kwangju Inst Sci & Technol, Dept Environm Sci & Engn, Kwangju 506303, South Korea. Foster Wheeler Environm Corp, Lakewood, CO 80228 USA. Texas Tech Univ, Dept Civil Engn, Lubbock, TX 79409 USA. Texas Tech Univ, Atmospher Sci Grp, Lubbock, TX 79409 USA. Great Basin Unified Air Pollut Control Dist, Bishop, CA 93514 USA. RP Gillette, DA (reprint author), NOAA, Air Resources Lab, Atmospher Sci Modelling Div, Res Triangle Pk, NC 27711 USA. OI Gill, Thomas E/0000-0001-9011-4105 NR 31 TC 21 Z9 21 U1 0 U2 5 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX PO19 1UD, ENGLAND SN 0197-9337 J9 EARTH SURF PROC LAND JI Earth Surf. Process. Landf. PD MAY PY 1999 VL 24 IS 5 BP 463 EP 479 DI 10.1002/(SICI)1096-9837(199905)24:5<463::AID-ESP2>3.0.CO;2-R PG 17 WC Geography, Physical; Geosciences, Multidisciplinary SC Physical Geography; Geology GA 198JJ UT WOS:000080420100008 ER PT J AU Yu, N Culver, DA AF Yu, N Culver, DA TI Estimating the effective clearance rate and refiltration by zebra mussels, Dreissena polymorpha, in a stratified reservoir SO FRESHWATER BIOLOGY LA English DT Article DE Dreissena; effective clearance rate; filtration rate; particulate inorganic matter; phytoplankton; refiltration; reservoir; water mixing ID WESTERN LAKE ERIE; SUSPENSION-FEEDING BIVALVES; WATER-QUALITY MANAGEMENT; BENTHIC BOUNDARY-LAYER; MYTILUS-EDULIS-L; FILTRATION-RATE; ALGAL CONCENTRATION; FILTERING IMPACTS; FOOD; SESTON AB 1. The grazing impact of zebra mussels, Dreissena polymorpha Pallas, is often evaluated by applying the individual filtration rate measured in the laboratory to the field abundance and then by comparing the total volume of water filtered with the whole lake volume. Since this approach overlooks refiltration, it overestimates the grazing impact of zebra mussels. To deal with this problem, the present authors developed an in situ method for collecting faeces and pseudofaeces to measure the actual volume of water that is cleared of suspended particles by Dreissena in a unit time under a given set of environmental conditions. This is termed the effective clearance rate (ECR). 2. The experiment was conducted in Hargus Lake, OH, U.S.A., a small thermally stratified reservoir, to test the effects of spatial aggregation, mussel density and the concentration of particulate inorganic matter (PIM) on the effective clearance rate of Dreissena. 3. Over 40 measurements, the ECR values ranged from 15.3 to 68.6 mt ind(-1) h(-1). Much of the variation can be explained by colony form, mussel density and seston concentration. The effects of these variables were all statistically significant. The average ECR for isolated individuals was higher than that for those in clumps (40.4 versus 32.8 mt Ind(-1) h(-1)), which is attributed to increased refiltration in the cores of the clumps. The ECR decreased with increased zebra mussel density because of intensified competition for food particles within the group. The ECR increased with increased PIM concentration in the lake water, which may be interpreted as a result of enhanced water mixing which ultimately caused increases in both sediment resuspension and particle delivery to the mussels. 4. Taking the filtration rates for a 20-mm mussel to be between 116 and 234 mt ind(-1) h(-1), based on data from the literature, the clumped mussels under the present experimental conditions would have a refiltration ratio between 3.4 and 6.9. 5. The present authors developed an areal clearance model which predicts that seston removal by the Dreissena population is limited by the particle delivery from the ambient water to the mussel bed and will reach a maximum value beyond which no further increase will occur with increased population density. 6. It is concluded that the direct grazing impact of zebra mussel on phytoplankton in thermally stratified lakes is much less effective than predicted from simple filtration rate estimation. C1 Ohio State Univ, Dept Ecol Evolut & Organismal Biol, Columbus, OH 43210 USA. RP Yu, N (reprint author), NOAA, Off Habitat Conservat, Natl Marine Fisheries Serv, 1315 E West Highway, Silver Spring, MD 20910 USA. EM yu.41@osu.edu NR 41 TC 25 Z9 26 U1 1 U2 19 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 0046-5070 J9 FRESHWATER BIOL JI Freshw. Biol. PD MAY PY 1999 VL 41 IS 3 BP 481 EP 492 DI 10.1046/j.1365-2427.1999.00393.x PG 12 WC Marine & Freshwater Biology SC Marine & Freshwater Biology GA 215BL UT WOS:000081362000001 ER PT J AU Sperber, KR AF Sperber, KR CA Participating AMIP Modelling Grp TI Are revised models better models? A skill score assessment of regional interannual variability SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID INTERCOMPARISON PROJECT; MONSOON; AMIP; PRECIPITATION; SENSITIVITY; RAINFALL; GCM AB Various skill scores are used to assess the performance of revised models relative to their original configurations. The interannual variability of all-India, Sahel and Nordeste rainfall and summer monsoon windshear is examined in integrations performed under the experimental design of the Atmospheric Model Intercomparison Project. For the indices considered, the revised models exhibit greater fidelity at simulating the observed interannual variability. Interannual variability of all-India rainfall is better simulated by models that have a more realistic rainfall climatology in the vicinity of India, indicating the beneficial effect of reducing systematic model error. C1 Univ Calif Lawrence Livermore Natl Lab, PCMDI, Livermore, CA 94550 USA. Res Ctr, Bur Meteorol, Melbourne, Vic, Australia. Ctr Natl Rech Meteorol, Toulouse, France. Dept Numer Math, Moscow, Russia. DERF, Geophys Fluid Dynam Lab, Princeton, NJ USA. Meteorol Dynam Lab, Paris, France. Max Planck Inst Meteorol, Hamburg, Germany. Meteorol Res Inst, Tsukuba, Ibaraki 305, Japan. USN, Res Lab, Monterey, CA USA. SUNY Albany, SNG, Albany, NY 12222 USA. Yonsei Univ, Seoul 120749, South Korea. RP Sperber, KR (reprint author), Univ Calif Lawrence Livermore Natl Lab, PCMDI, POB 808,L-264, Livermore, CA 94550 USA. RI Sperber, Kenneth/H-2333-2012 NR 23 TC 17 Z9 17 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 MAY 1 PY 1999 VL 26 IS 9 BP 1267 EP 1270 DI 10.1029/1999GL900227 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 193EL UT WOS:000080122900021 ER PT J AU Tuck, AF Hovde, SJ AF Tuck, AF Hovde, SJ TI Fractal behavior of ozone, wind and temperature in the lower stratosphere SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID ER-2 AIRCRAFT; TIME-SERIES; SPECTRA AB We apply a measure from fractal geometry to time series of airborne observations of ozone and meteorological quantities in the lower stratosphere. The Hurst exponent measure demonstrates that the lower stratospheric ozone, wind and temperature obey single exponent power law scaling to a high degree of fidelity. As a result, we suggest that ozone and horizontal windspeed behave as random, self-affine fractals, that vertical wind speed behaves antipersistently and that horizontal wind direction and temperature behave persistently. The persistent variables are candidates for multifractality. C1 Natl Ocean & Atmospher Adm, Aeron Lab, Boulder, CO USA. Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. RP Tuck, AF (reprint author), Natl Ocean & Atmospher Adm, Aeron Lab, Boulder, CO USA. RI Tuck, Adrian/F-6024-2011 OI Tuck, Adrian/0000-0002-2074-0538 NR 15 TC 31 Z9 31 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD MAY 1 PY 1999 VL 26 IS 9 BP 1271 EP 1274 DI 10.1029/1999GL900233 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 193EL UT WOS:000080122900022 ER PT J AU Overland, JE Salo, S Adams, JR AF Overland, JE Salo, S Adams, JR TI Salinity signature of the Pacific Decadal Oscillation SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID VARIABILITY; OCEAN AB Three sites in the North Pacific have temperature and salinity observations in most months for several years before and after 1977. The Gulf of Alaska station (57 degrees N, 148 degrees W) showed a 2 degrees C warming and a 0.6 freshening in salinity at 10 m depth in the 1980s compared to the 1970s. OWS PAPA (50 degrees N, 145 degrees W) and PAPA line station 7 (49.1 degrees N, 132.4 degrees W) show warming of 0.6 degrees C and 0.9 degrees C, with no major salinity change. The decrease in density and increase in stratification in the Gulf of Alaska after 1977 corresponds primarily to a decrease in salinity in the upper 150 m. We propose that while the Pacific Decadal Oscillation has an east/west character in temperature, the salinity signature will have a NNW/SSE character, similar to the pattern of interannual variability in precipitation. C1 NOAA, Pacific Marine Environm Lab, Seattle, WA 98115 USA. Univ Washington, Joint Inst Study Atmosphere & Oceans, Seattle, WA 98195 USA. RP Overland, JE (reprint author), NOAA, Pacific Marine Environm Lab, 7600 Sand Point Way NE, Seattle, WA 98115 USA. NR 13 TC 26 Z9 27 U1 2 U2 6 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD MAY 1 PY 1999 VL 26 IS 9 BP 1337 EP 1340 DI 10.1029/1999GL900241 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 193EL UT WOS:000080122900039 ER PT J AU Wang, H Ting, MF Ji, M AF Wang, H Ting, MF Ji, M TI Prediction of seasonal mean United States precipitation based on El Nino sea surface temperatures SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID PATTERNS; ENSO AB A method for seasonal predictions of U.S. precipitation based on tropical Pacific sea surface temperature (SST) anomalies is developed in this letter with the singular value decomposition(SVD). This method was applied to the 1997/98 El Nino. The 1997 summer and 1997/98 winter precipitation over the United States were predicted using forecast SST from the National Centers for Environmental Prediction (NCEP) coupled ocean-atmosphere model. A cross validation, based on the percentages of hit between the hindcast and observed precipitation for the past El Nino and La Nina events, indicates a certain degree of predictability in both winter and summer seasons. During El Nino, significant predictability of summer precipitation is found over the Northern Plains and Atlantic States, while during La Nina it is in the Midwest. Above normal precipitation in the Northern Plains and the Midwest and below normal precipitation in the Atlantic States is associated with a warm phase of the El Nino-Southern Oscillation (ENSO) in summer. For winter precipitation, significant predictability is detected over the Gulf Coast States, the Southern Plains and California. Over these regions, wetter conditions are generally associated with the warm phase of ENSO. C1 Univ Illinois, Dept Atmospher Sci, Urbana, IL 61801 USA. NOAA, NWS, NCEP, Environm Modeling Ctr, Washington, DC 20233 USA. RP Wang, H (reprint author), Univ Arizona, Tucson, AZ 85721 USA. RI Wang, Hui/B-6516-2008 NR 12 TC 13 Z9 13 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD MAY 1 PY 1999 VL 26 IS 9 BP 1341 EP 1344 DI 10.1029/1999GL900230 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 193EL UT WOS:000080122900040 ER PT J AU Lohmann, D Lettenmaier, DP Liang, X Wood, EF Boone, A Chang, S Chen, F Dai, YJ Desborough, C Dickinson, RE Duan, QY Ek, M Gusev, YM Habets, F Irannejad, P Koster, R Mitchell, KE Nasonova, ON Noilhan, J Schaake, J Schlosser, A Shao, YP Shmakin, AB Verseghy, D Warrach, K Wetzel, P Xue, YK Yang, ZL Zeng, QC AF Lohmann, D Lettenmaier, DP Liang, X Wood, EF Boone, A Chang, S Chen, F Dai, YJ Desborough, C Dickinson, RE Duan, QY Ek, M Gusev, YM Habets, F Irannejad, P Koster, R Mitchell, KE Nasonova, ON Noilhan, J Schaake, J Schlosser, A Shao, YP Shmakin, AB Verseghy, D Warrach, K Wetzel, P Xue, YK Yang, ZL Zeng, QC TI The project for intercomparison of land-surface parameterization schemes (PILPS) phase 2(c) Red-arkansas river basin experiment 3. Spatial and temporal analysis of water fluxes (vol 19, pg 161, 1998) SO GLOBAL AND PLANETARY CHANGE LA English DT Correction C1 Princeton Univ, Dept Civil Engn & Operat Res, Princeton, NJ 08544 USA. Univ Washington, Dept Civil Engn, Seattle, WA 98195 USA. NASA, Mesoscale Dynam & Precipitat Branch, GSFC, Greenbelt, MD USA. USAF, Res Lab, Hanscom, MA USA. NOAA, NCEP, Environm Modeling Ctr, Camp Springs, MD USA. Chinese Acad Sci, Inst Atmospher Phys, Beijing, Peoples R China. Macquarie Univ, Climat Impacts Ctr, Sydney, NSW, Australia. Univ Arizona, Inst Atmospher Phys, Tucson, AZ 85721 USA. NOAA, NWS, Off Hydrol, Silver Spring, MD USA. Oregon State Univ, Corvallis, OR 97331 USA. Russian Acad Sci, Inst Water Problems, Moscow, Russia. CNRM, MeteoFrance, Toulouse, France. Univ New S Wales, Ctr Adv Numer Computat Engn & Sci, Sydney, NSW 2052, Australia. NASA, Hydrol Sci Branch, GSFC, Greenbelt, MD USA. NOAA, GFDL, Princeton, NJ USA. Inst Geog, Moscow, Russia. RP Lohmann, D (reprint author), Princeton Univ, Dept Civil Engn & Operat Res, Princeton, NJ 08544 USA. RI Yang, Zong-Liang/B-4916-2011; Koster, Randal/F-5881-2012; lettenmaier, dennis/F-8780-2011; Nasonova, Olga/B-6093-2014; Duan, Qingyun/C-7652-2011; gusev, yugeniy/G-4711-2014; Shao, Yaping/G-3606-2013 OI Koster, Randal/0000-0001-6418-6383; lettenmaier, dennis/0000-0003-3317-1327; Duan, Qingyun/0000-0001-9955-1512; gusev, yugeniy/0000-0003-3886-2143; Shao, Yaping/0000-0002-2041-5479 NR 1 TC 0 Z9 0 U1 0 U2 8 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-8181 J9 GLOBAL PLANET CHANGE JI Glob. Planet. Change PD MAY PY 1999 VL 20 IS 4 BP 291 EP 295 PG 5 WC Geography, Physical; Geosciences, Multidisciplinary SC Physical Geography; Geology GA 215BP UT WOS:000081362300007 ER PT J AU Buckley, L Caldarone, E Ong, TL AF Buckley, L Caldarone, E Ong, TL TI RNA-DNA ratio and other nucleic acid-based indicators for growth and condition of marine fishes SO HYDROBIOLOGIA LA English DT Article; Proceedings Paper CT Special Session on the Application of Molecular Techniques to Aquatic Communities, at the American-Society-for-Limnology-and-Oceanography-Aquatic-Sciences Meeting CY 1997 CL SANTA FE, NEW MEXICO SP Amer Soc Limnol & Oceanog Aquat Sci DE nucleic acids; fish larvae; RNA/DNA; condition; growth ID COD GADUS-MORHUA; HERRING CLUPEA-HARENGUS; DRUM SCIAENOPS-OCELLATUS; NUTRITIONAL CONDITION; RNA/DNA RATIOS; ATLANTIC COD; LARVAL FISH; BIOCHEMICAL-COMPOSITION; VERTICAL-DISTRIBUTION; PROTEIN-CONTENT AB Nucleic acid analysis has provided useful tools to study recent growth and mortality of young fishes and their responses to environmental variability. The ratio of RNA-DNA (R/D) has been shown to respond to changes in feeding conditions and growth after periods as short as 1-3 days in a variety of fish species. The earliest studies used primarily UV-based methods, but most investigators now use more sensitive, fluorometric dye-binding assays to estimate RNA and DNA in individual larvae. These newer methods are very sensitive to procedural details and choice of standards. Analytical methods, normalization and calibration procedures to optimize information obtained from nucleic acid analysis are discussed. We present examples illustrating the technique's utility, and problems encountered when applying nucleic acid-based indices to fish larvae and early juveniles. The wide use of R/D analysis in studies of fish early life stages, together with a proliferation of analytical methods, demands a major intercalibration exercise. C1 Univ Rhode Isl, Grad Sch Oceanog, NOAA, CMER Program, Narragansett, RI 02882 USA. NOAA, Natl Marine Fisheries Serv, NE Fisheries Sci Ctr, Narragansett, RI 02882 USA. RP Buckley, L (reprint author), Univ Rhode Isl, Grad Sch Oceanog, NOAA, CMER Program, Narragansett, RI 02882 USA. NR 66 TC 182 Z9 192 U1 0 U2 30 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS SN 0018-8158 J9 HYDROBIOLOGIA JI Hydrobiologia PD MAY PY 1999 VL 401 BP 265 EP 277 DI 10.1023/A:1003798613241 PG 13 WC Marine & Freshwater Biology SC Marine & Freshwater Biology GA 248LR UT WOS:000083276500021 ER PT J AU Williams, DF Alpert, BK AF Williams, DF Alpert, BK TI Characteristic impedance, power, and causality SO IEEE MICROWAVE AND GUIDED WAVE LETTERS LA English DT Article DE causality; characteristic impedance; microwave circuit theory AB A new causal power-normalized waveguide equivalent-circuit theory determines uniquely both the magnitude and phase of the characteristic impedance of a waveguide. C1 Natl Inst Stand & Technol, Boulder, CO 80303 USA. RP Williams, DF (reprint author), Natl Inst Stand & Technol, 325 Broadway, Boulder, CO 80303 USA. NR 5 TC 5 Z9 5 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 1051-8207 J9 IEEE MICROW GUIDED W JI IEEE Microw. Guided Wave Lett. PD MAY PY 1999 VL 9 IS 5 BP 181 EP 182 DI 10.1109/75.766757 PG 2 WC Engineering, Electrical & Electronic SC Engineering GA 201DJ UT WOS:000080579400001 ER PT J AU Kanda, M Kawalko, SF AF Kanda, M Kawalko, SF TI Near-zone gain of 500 MHz to 2.6 GHz rectangular standard pyramidal horns SO IEEE TRANSACTIONS ON ELECTROMAGNETIC COMPATIBILITY LA English DT Article DE anechoic chamber; near-zone gain; standard pyramidal horn ID SURFACES; FIELD AB Full-wave solutions to the problem of radiation by rectangular standard pyramidal horn antennas are presented. The radiation problem is formulated in terms of an electric field integral equation (EFIE), which is solved using the method of moments (MoM) for four rectangular standard pyramidal horns covering the frequency range from 500 MHz to 2.6 GHz, Results for the near-zone gains as a function distance from the aperture of the horn antenna are presented. A comparison is made with the analytical formula for the fields and near-zone gains. C1 Natl Inst Stand & Technol, Boulder, CO 80303 USA. Electro Magnet Applicat Inc, Lakewood, CO 80226 USA. RP Kanda, M (reprint author), Natl Inst Stand & Technol, 325 Broadway, Boulder, CO 80303 USA. NR 11 TC 6 Z9 6 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 1999 VL 41 IS 2 BP 85 EP 92 DI 10.1109/15.765095 PG 8 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA 197EM UT WOS:000080351700001 ER PT J AU Zhang, W Lahteenmaki, J Vainikainen, P AF Zhang, W Lahteenmaki, J Vainikainen, P TI A practical aspect of over-rooftop multiple-building forward diffraction from a low source SO IEEE TRANSACTIONS ON ELECTROMAGNETIC COMPATIBILITY LA English DT Article DE microcellular mobile radio; multiple diffraction; radio propagation ID ATTENUATION FUNCTION; UHF PROPAGATION; MODEL; ENVIRONMENTS; URBAN; EDGE; UTD AB A practical aspect of over-rooftop multiple-building forward diffraction from a low source is presented, including two formulations and an introduction of their application. In particular, the low-loss formulation for multiple diffraction exposes a factor that can account for strong over-rooftop radio propagation. Both low- and high-loss formulations take the advantages of the uniform geometrical theory of diffraction and physical optics (PO) and have the major advantage of significantly shortening the computing time over existing formulations. They behave well, particularly in and near the transition zone, and are written in explicit forms additionally for soft boundary that corresponds to vertical polarization transmission and reception in the horizontal plane. The application in the vertical plane for the total received signal strength prediction is introduced using the formulations for hard boundary corresponding to vertical polarization transmission and reception. C1 Helsinki Univ Technol, Inst Radio Commun, Radio Lab, FIN-02015 Espoo, Finland. VTT Informat Technol, FIN-02044 VTT, Finland. RP Zhang, W (reprint author), Natl Inst Stand & Technol, Wireless Commun Technol Grp, Adv Network Technol Div, Gaithersburg, MD 20899 USA. NR 9 TC 8 Z9 9 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 1999 VL 41 IS 2 BP 115 EP 119 DI 10.1109/15.765099 PG 5 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA 197EM UT WOS:000080351700005 ER PT J AU Lopez-Diaz, L Eicke, J Della Torre, E AF Lopez-Diaz, L Eicke, J Della Torre, E TI A comparison of micromagnetic solvers SO IEEE TRANSACTIONS ON MAGNETICS LA English DT Article; Proceedings Paper CT 8th Biennial IEEE Conference on Electromagnetic Field Computation (IEEE CEFC 98) CY JUN 01-03, 1998 CL TUCSON, AZ SP IEEE DE numerical micromagnetics; PDE solvers; conjugate gradient method ID STIFF MODES AB Micromagnetic equations have characteristics that differ from electromagnetic field problems. Under certain conditions, EM solvers are not very efficient. This paper compares the speed of several micromagnetic solvers on two different problems. C1 Univ Salamanca, Dept Fis Aplicada, E-37071 Salamanca, Spain. George Washington Univ, Inst Magnet Res, Washington, DC 20052 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Univ Salamanca, Dept Fis Aplicada, E-37071 Salamanca, Spain. EM lld@gugu.usal.es; jeicke@seas.gwu.edu; dellator@seas.gwu.edu NR 9 TC 10 Z9 10 U1 0 U2 0 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 MAY PY 1999 VL 35 IS 3 BP 1207 EP 1210 DI 10.1109/20.767166 PN 1 PG 4 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA 199PM UT WOS:000080490900027 ER PT J AU Lewis, D Della Torre, E AF Lewis, D Della Torre, E TI Automatic pushing applied to micromagnetic calculations of domain wall motion SO IEEE TRANSACTIONS ON MAGNETICS LA English DT Article; Proceedings Paper CT 8th Biennial IEEE Conference on Electromagnetic Field Computation (IEEE CEFC 98) CY JUN 01-03, 1998 CL TUCSON, ARIZONA SP IEEE DE micromagnetics; convergence; domain wall; inclusion ID COERCIVITY AB Two methods of mode pushing are compared. The newer method, Automatic pushing, uses energy minimization to relocate a wall, as one entity. The older method, Adaptive mode pushing, uses the reversal of the direction of motion of the wall to determine when to end the mode pushing. It is seen that automatic pushing is comparable and often speeds up the calculation significantly more than adaptive mode pushing. C1 Read Rite Corp, Fremont, CA USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. George Washington Univ, Inst Res Magnet, Washington, DC 20052 USA. RP Lewis, D (reprint author), Read Rite Corp, Fremont, CA USA. NR 5 TC 0 Z9 0 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9464 J9 IEEE T MAGN JI IEEE Trans. Magn. PD MAY PY 1999 VL 35 IS 3 BP 1219 EP 1222 DI 10.1109/20.767169 PN 1 PG 4 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA 199PM UT WOS:000080490900030 ER PT J AU Reimers, A Della Torre, E AF Reimers, A Della Torre, E TI Fast Preisach based magnetostriction model for highly magnetostrictive materials SO IEEE TRANSACTIONS ON MAGNETICS LA English DT Article; Proceedings Paper CT 8th Biennial IEEE Conference on Electromagnetic Field Computation (IEEE CEFC 98) CY JUN 01-03, 1998 CL TUCSON, ARIZONA SP IEEE DE magnetostriction; Preisach; bimodal; Terfenol ID MAGNETIZATION AB A Preisach based magnetization model is presented to work specifically on highly magnetostrictive materials. The model accounts for the additional anisotropy introduced when a prestress is used to activate the high strain, by using a bimodal structure, The necessity of strain feedback to deal with the magneto-mechanical effect is discussed for Terfenol-D specifically. The model is based on a fast implementation of the DOK magnetization model, so it is suitable for real time control applications. C1 George Washington Univ, Inst Magnet Res, Washington, DC 20052 USA. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Reimers, A (reprint author), George Washington Univ, Inst Magnet Res, Washington, DC 20052 USA. NR 7 TC 8 Z9 9 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9464 J9 IEEE T MAGN JI IEEE Trans. Magn. PD MAY PY 1999 VL 35 IS 3 BP 1239 EP 1242 DI 10.1109/20.767174 PN 1 PG 4 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA 199PM UT WOS:000080490900035 ER PT J AU Johnson, JL Padgett, ML Omidvar, O AF Johnson, JL Padgett, ML Omidvar, O TI Overview of pulse coupled neural network (PCNN) special issue SO IEEE TRANSACTIONS ON NEURAL NETWORKS LA English DT Editorial Material DE pulse coupled neural networks AB Pulse coupled neural networks (PCNN's) have proven to be highly effective when used in a diverse set of applications. The theory is based on biological studies of pulse synchronization. The editors present this special issue in response to numerous requests from colleagues for more information on PCNN's. C1 USA, Redstone Arsenal, AL 35898 USA. NIST, Gaithersburg, MD USA. RP Johnson, JL (reprint author), USA, Redstone Arsenal, AL 35898 USA. NR 0 TC 21 Z9 21 U1 0 U2 6 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 1045-9227 J9 IEEE T NEURAL NETWOR JI IEEE Trans. Neural Netw. PD MAY PY 1999 VL 10 IS 3 BP 461 EP 463 DI 10.1109/TNN.1999.761704 PG 3 WC Computer Science, Artificial Intelligence; Computer Science, Hardware & Architecture; Computer Science, Theory & Methods; Engineering, Electrical & Electronic SC Computer Science; Engineering GA 193EJ UT WOS:000080122700001 ER PT J AU Cresswell, MW Guillaume, NMP Lee, WE Allen, RA Guthrie, WF Ghoshtagore, RN Osborne, ZE Sullivan, N Linholm, LW AF Cresswell, MW Guillaume, NMP Lee, WE Allen, RA Guthrie, WF Ghoshtagore, RN Osborne, ZE Sullivan, N Linholm, LW TI Extraction of sheet resistance from four-terminal sheet resistors replicated in monocrystalline films with nonplanar geometries SO IEEE TRANSACTIONS ON SEMICONDUCTOR MANUFACTURING LA English DT Article DE CD; linewidth; lithography; metrology; reference artifact; semiconductor; sheet resistance AB This paper describes limitations of conventional methods of extracting sheet resistance from four-terminal sheet resistors incorporated into electrical linewidth test structures that are patterned in (110) monocrystalline silicon-on-insulator (SOI) films, Nonplanar sections of these structures render the extraction of sheet resistance by conventional techniques subject to systematic errors, The errors are addressed here by algorithms incorporating the results of finite-element current-flow analysis, The intended end application is to facilitate the use of the uniquely high repeatability and low cost of electrical critical dimension (CD) metrology as a secondary reference in a traceability path for CD-reference artifacts. C1 NIST, Div Semicond Elect, Gaithersburg, MD 20899 USA. Reinshaw Plc, Transducer Syst Div, Wottonunder Edge GL12 7DH, Glos, England. NIST, Stat Engn Div, Gaithersburg, MD 20899 USA. Appl Mat Inc, Process Diagnost & Control Grp, Santa Clara, CA 95054 USA. Digital Semicond, Hudson, MA 01749 USA. Schlumberger Automated Test Equipment, Concord, MA 01742 USA. RP Cresswell, MW (reprint author), NIST, Div Semicond Elect, Gaithersburg, MD 20899 USA. NR 13 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 0894-6507 J9 IEEE T SEMICONDUCT M JI IEEE Trans. Semicond. Manuf. PD MAY PY 1999 VL 12 IS 2 BP 154 EP 165 DI 10.1109/66.762872 PG 12 WC Engineering, Manufacturing; Engineering, Electrical & Electronic; Physics, Applied; Physics, Condensed Matter SC Engineering; Physics GA 193ED UT WOS:000080122200002 ER PT J AU Parker, TE AF Parker, TE TI Environmental factors and hydrogen maser frequency stability SO IEEE TRANSACTIONS ON ULTRASONICS FERROELECTRICS AND FREQUENCY CONTROL LA English DT Article AB It is necessary to have a complete understanding of the environmental sensitivities of cavity-tuned hydrogen masers to obtain optimum frequency stability and to avoid common-mode frequency fluctuations. Measurements of environmental sensitivities (temperature, relative humidity, atmospheric pressure, line voltage and magnetic field) made at the National Institute of Standards and Technology have demonstrated that the frequency stability of a cavity-tuned, active hydrogen maser is not significantly degraded if the maser is operated in a moderately controlled environment. Under these conditions, common-mode frequency fluctuations caused by the observed environmental factors also are negligible. C1 Natl Inst Stand & Technol, Div Time & Frequency, Boulder, CO 80303 USA. RP Parker, TE (reprint author), Natl Inst Stand & Technol, Div Time & Frequency, 847-5, Boulder, CO 80303 USA. NR 11 TC 8 Z9 9 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 0885-3010 J9 IEEE T ULTRASON FERR JI IEEE Trans. Ultrason. Ferroelectr. Freq. Control PD MAY PY 1999 VL 46 IS 3 BP 745 EP 751 DI 10.1109/58.764861 PG 7 WC Acoustics; Engineering, Electrical & Electronic SC Acoustics; Engineering GA 196WW UT WOS:000080331700029 PM 18238475 ER PT J AU Fu, CB Diaz, HF Dong, DF Fletcher, JO AF Fu, CB Diaz, HF Dong, DF Fletcher, JO TI Changes in atmospheric circulation over Northern Hemisphere oceans associated with the rapid warming of the 1920s SO INTERNATIONAL JOURNAL OF CLIMATOLOGY LA English DT Article DE rapid climate change; surface temperature; Northern Hemisphere; North Atlantic; early 20th century ID AIR-TEMPERATURE VARIATIONS; ATLANTIC OSCILLATION; CLIMATE VARIABILITY; SEA ICE; SURFACE; PACIFIC; TRENDS; PRECIPITATION; FLUCTUATIONS; AMERICA AB Global mean surface temperature has increased since the late 19th century. The warming occurred largely during two periods: 1920-1940, and since the mid-1970s. Although most recent studies have focused on the latter period, it is of interest to analyse the earlier period and compare its major features to the recent warming episode. The warming during 1920-1940 occurred most rapidly during the 1920s. It was strongest at high northern latitudes in winter, a pattern now believed to be characteristic of 'greenhouse warming'. This warming of the Arctic was much discussed during the 1930s and 1940s, but the data available at that time were mostly derived from land areas. In this paper, we use the COADS marine data set and recent compilations of land surface temperature data sets to examine the behaviour of the surface fields over the ocean during this event. Considering the thermal and atmospheric fields at the surface, the strongest signal occurs in the North Atlantic Ocean during winter, being distinct but more gradual in the other oceans and seasons. The Northern Hemisphere continental record shows that both middle and high latitudes experienced rapid warming in the early 20th century warming interval (the 1920s and 1930s, hereafter referred to as ETCW). Temperature data for northern tropics, while displaying similar general characteristics, exhibit some differences with regard to timing and rates of change. There is a suggestion of weakening of the westerlies and the trade wind system in the 1930s, following an intensification of the westerlies across the North Atlantic during the previous two decades. This weakening may be related to a lessening of atmospheric baroclinicity in association with the fact that the amplitude of warming at high latitudes was much greater than that in low latitudes, reducing the mean meridional thermal gradient, and therefore the geostrophic pressure gradient. There is some indication that the North Atlantic and North Pacific high-pressure systems shifted northward. Coincident with this northward shift of the subtropical highs, typhoons in the Northwest Pacific and hurricanes in the North Atlantic became more numerous in this period of rising temperature, which we suggest is linked to a northward shift of the respective near-equatorial convergence zones. Concomitant to the weakening of the westerlies and trade wind systems, the Asian monsoon troughs deepened substantially, a situation generally favourable to the development of active monsoons. It is thought that the combination of these two features-enhanced continental monsoons and implied lowered vertical wind shear over the oceans-would tend to enhance the release of latent heat in the tropics, representing strengthened Hadley and Walker circulations, which may have been at least partly responsible for greater aridity in subtropical land areas of both hemispheres during this period. The latter is also consistent with an expansion and/or strengthening of the subtropical high-pressure belt into the continents. Copyright (C) 1999 Royal Meteorological Society. C1 Acad Sinica, Inst Atmospher Phys, Beijing 100029, Peoples R China. NOAA, ERL, Boulder, CO 80303 USA. RP Fu, CB (reprint author), Acad Sinica, Inst Atmospher Phys, Beijing 100029, Peoples R China. NR 69 TC 41 Z9 45 U1 0 U2 7 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX PO19 1UD, ENGLAND SN 0899-8418 J9 INT J CLIMATOL JI Int. J. Climatol. PD MAY PY 1999 VL 19 IS 6 BP 581 EP 606 DI 10.1002/(SICI)1097-0088(199905)19:6<581::AID-JOC396>3.3.CO;2-G PG 26 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 199KK UT WOS:000080480200001 ER PT J AU Liao, K Schultheisz, CR Hunston, DL AF Liao, K Schultheisz, CR Hunston, DL TI Long-term environmental fatigue of pultruded glass-fiber-reinforced composites under flexural loading SO INTERNATIONAL JOURNAL OF FATIGUE LA English DT Article DE accelerated aging; bending fatigue; composites; fiber matrix interphase; glass fiber; pultrusion; salt solution; vinyl ester; water ID STRUCTURAL APPLICATIONS; INFRASTRUCTURE; PLASTICS AB Pultruded glass-fiber-reinforced vinyl ester composite coupons were subjected to four-point-bend fatigue in various environments to study long-term durability for infrastructure applications. Several groups of specimens were aged in water or in salt solutions containing mass fractions of either 5% NaCl or 10% NaCl for up to 6570 h. Both as-received and aged specimens were then cyclically tested in air or while immersed in water or in salt solution. For specimens cyclically loaded at or above 45% of the average flexural strength of the dry coupons, no substantial difference in fatigue life was observed among all the specimen groups. For samples cyclically loaded at 30% of the dry flexural strength, however, all specimens tested in air survived beyond 10(7) cycles while all those tested in water environments did not. It is found that long-term environmental fatigue behavior is not controlled by the quantity of water absorbed; rather, it is governed by a combination of both load and fluid environment. No difference in fatigue life was found for specimens aged in different fluid environments at room temperature prior to fatigue testing. Relative to these samples, however, a significant difference was seen for specimens aged in water at 75 degrees C for 2400 h prior to cyclic test at load levels above 30% of the dry flexural strength. When tested at 30% of the dry flexural strength the differences were within the experimental uncertainty. Microscopic examination of the fatigue specimens revealed evidence of a degraded fiber/matrix interphase region in those specimens where environmental exposure caused premature failure so this is believed to be a controlling factor in the environmental performance of the glass composite. (C) 1999 Elsevier Science Ltd. All rights reserved. C1 Nanyang Technol Univ, Div Mat Engn, Sch Appl Sci, Nanyang 639798, Singapore. Natl Inst Stand & Technol, Div Polymers, Gaithersburg, MD 20899 USA. RP Liao, K (reprint author), Nanyang Technol Univ, Div Mat Engn, Sch Appl Sci, Nanyang 639798, Singapore. RI Liao, Kin/A-7915-2014 OI Liao, Kin/0000-0001-6352-2349 NR 40 TC 23 Z9 23 U1 0 U2 4 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0142-1123 J9 INT J FATIGUE JI Int. J. Fatigue PD MAY PY 1999 VL 21 IS 5 BP 485 EP 495 DI 10.1016/S0142-1123(98)00088-7 PG 11 WC Engineering, Mechanical; Materials Science, Multidisciplinary SC Engineering; Materials Science GA 197WG UT WOS:000080388700008 ER PT J AU Telles, EM Zink, LR Evenson, KM AF Telles, EM Zink, LR Evenson, KM TI New optically pumped FIR laser lines and frequency measurements from CH3OD SO INTERNATIONAL JOURNAL OF INFRARED AND MILLIMETER WAVES LA English DT Article ID CW CO2-LASER; METHANOL; SPECTRA; BAND AB This work reports the discovery of 45 new optically pumped far-infrared (FIR) laser lines from CH3OD in the range 42.6 mu m to 207.2 mu m. A highly efficient CO2 laser was used as the pump laser for an Optically-pumped Fabry-Perot FIR laser. The frequencies of most of the new lines were measured in the range 1.7 to 6.4 THz. Twenty-eight CO2 lines were used as pump lines; nineteen of these had frequencies lower than those previously used to pump CH3OD in a FIR laser. Sixteen of the new FIR lines had absorption transitions which belong to the OD bending vibrational mode. C1 Natl Inst Stand & Technol, Div Time & Frequency, Boulder, CO 80303 USA. NR 14 TC 8 Z9 8 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 1999 VL 20 IS 5 BP 741 EP 758 DI 10.1023/A:1021753613395 PG 18 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA 193PZ UT WOS:000080146400001 ER PT J AU Lemmon, EW Jacobsen, RT AF Lemmon, EW Jacobsen, RT TI A generalized model for the thermodynamic properties of mixtures SO INTERNATIONAL JOURNAL OF THERMOPHYSICS LA English DT Article; Proceedings Paper CT 13th Symposium on Thermophysical Properties CY JUN 22-27, 1997 CL UNIV COLORADO, BOULDER, COLORADO SP Amer Soc Mech Engineers, Heat Transfer Div, Standing Comm Thermophys Properties, Natl Inst Stand & Technol, Chem Sci & Technol Lab, Phys & Chem Properties Div HO UNIV COLORADO DE cryogens; equation of state; hydrocarbons; mixtures; refrigerants; thermodynamic properties ID METHANE + ETHANE; TRIPLE-POINT; PRESSURES; EQUATION; STATE; NITROGEN; 1000-MPA; FLUIDS; OXYGEN; 320-K AB A mixture model explicit in Helmholtz energy has been developed which is capable of predicting thermodynamic properties of mixtures containing nitrogen, argon, oxygen, carbon dioxide, methane, ethane, propane, n-butane, i-butane, R-32, R-125, R-134a, and R-152a within the estimated accuracy of available experimental data. The Helmholtz energy of the mixture is the sum of the ideal gas contribution, the compressibility (or real gas) contribution, and the contribution from mixing. The contribution from mixing is given by a single generalized equation which is applied to all mixtures studied in this work. The independent variables are the density, temperature, and composition. The model may be used to calculate the thermodynamic properties of mixtures at various compositions including dew and bubble point properties and critical points. It incorporates accurate published equations of state for each pure fluid. The estimated accuracy of calculated properties is +/-0.2% in density, +/-0.1% in the speed of sound at pressures below 10 MPa, +/-0.5% in the speed of sound for pressures above 10 MPa, and +/-1% in heat capacities. In the region from 250 to 350 K at pressures up to 30 MPa, calculated densities are within +/-0.1% for most gaseous phase mixtures. For binary mixtures where the critical point temperatures of the pure fluid constituents are within 100K of each other, calculated bubble point pressures are generally accurate to within +/- 1 to 2%. For mixtures with critical points further apart, calculated bubble point pressures are generally accurate to within +/-5 to 10%. C1 Natl Inst Stand & Technol, Phys & Chem Properties Div, Boulder, CO 80303 USA. Univ Idaho, Ctr Appl Thermodynam Studies, Moscow, ID 83844 USA. RP Lemmon, EW (reprint author), Natl Inst Stand & Technol, Phys & Chem Properties Div, 325 Broadway, Boulder, CO 80303 USA. NR 28 TC 86 Z9 93 U1 2 U2 20 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 1999 VL 20 IS 3 BP 825 EP 835 DI 10.1023/A:1022627001338 PG 11 WC Thermodynamics; Chemistry, Physical; Mechanics; Physics, Applied SC Thermodynamics; Chemistry; Mechanics; Physics GA 214GV UT WOS:000081321000005 ER PT J AU Matsumoto, T Cezairliyan, A Basak, D AF Matsumoto, T Cezairliyan, A Basak, D TI Hemispherical total emissivity of niobium, molybdenum, and tungsten at high temperatures using a combined transient and brief steady-state technique SO INTERNATIONAL JOURNAL OF THERMOPHYSICS LA English DT Article; Proceedings Paper CT 13th Symposium on Thermophysical Properties CY JUN 22-27, 1997 CL UNIV COLORADO, BOULDER, COLORADO SP Amer Soc Mech Engineers, Heat Transfer Div, Standing Comm Thermophys Properties, Natl Inst Stand & Technol, Chem Sci & Technol Lab, Phys & Chem Properties Div HO UNIV COLORADO DE hemispherical total emissivity; high temperature; molybdenum; niobium; normal spectral emissivity; pulse heating; tungsten AB The hemispherical total emissivity of three refractory metals, niobium, molybdenum, and tungsten, was measured with a new method using a combined transient and brief steady-state technique. The technique is based on rapid resistive self-heating of a solid cylindrical specimen in vacuum up to a preset high temperature in a short time (about 200 ms) and then keeping the specimen at that temperature under steady-stale conditions for a brief period (about 500 ms) before switching off the current through the specimen. Hemispherical total emissivity is determined at the temperature plateau from the data on current through the specimen, the voltage drop across the middle portion of the specimen, and the specimen temperature using the steady-stale heat balance equation based on the Stefan-Boltzmann law. Temperature of the specimen is determined from the measured surface radiance temperature and the normal spectral emissivity; the latter is obtained from laser polarimetric measurements. Experimental results on the hemispherical total emissivity of niobium (2000 to 2600 K), molybdenum (2000 to 2700 K), and tungsten (2000 to 3400 K) are reported. C1 Natl Inst Stand & Technol, Div Met, Gaithersburg, MD 20899 USA. Natl Res Lab Metrol, Measurement Syst Dept, Ibaraki, Osaka 3058563, Japan. RP Basak, D (reprint author), Natl Inst Stand & Technol, Div Met, Gaithersburg, MD 20899 USA. NR 27 TC 23 Z9 23 U1 2 U2 15 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 1999 VL 20 IS 3 BP 943 EP 952 DI 10.1023/A:1022699622719 PG 10 WC Thermodynamics; Chemistry, Physical; Mechanics; Physics, Applied SC Thermodynamics; Chemistry; Mechanics; Physics GA 214GV UT WOS:000081321000016 ER PT J AU Ma, XL Schmit, TJ Smith, WL AF Ma, XL Schmit, TJ Smith, WL TI A nonlinear physical retrieval algorithm - Its application to the GOES-8/9 sounder SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID TEMPERATURE; TOVS; INVERSION; RADIANCES; PROFILES AB A nonlinear physical retrieval algorithm is developed and applied to the GOES-8/9 sounder radiance observations. The algorithm utilizes Newtonian iteration in which the maximum probability solution for temperature and water vapor profiles is achieved through the inverse solution of the nonlinear radiative transfer equation. The nonlinear physical retrieval algorithm has been tested for one year. It has also been implemented operationally by the National Oceanic and Atmospheric Administration National Environmental Satellite, Data and Information Service during February 1997. Results show that the GOES retrievals of temperature and moisture obtained with the nonlinear algorithm more closely agree with collocated radiosondes than the National Centers for Environmental Prediction (NCEP) forecast temperature and moisture profile used as the initial profile for the solution. The root-mean-square error of the total water vapor from the solution first guess, which is the NCEP 12-h forecast (referred to as the "background"), is reduced approximately 20% over the conventional data-rich North American region with the largest changes being achieved in areas of sparse radiosonde data coverage. C1 NOAA, NESDIS, ASPT, Off Res & Applicat, Madison, WI 53706 USA. Univ Wisconsin, Cooperat Inst Meteorol Satellite Studies, Ctr Space Sci & Engn, Madison, WI USA. RP Schmit, TJ (reprint author), NOAA, NESDIS, ASPT, Off Res & Applicat, 1225 W Dayton St, Madison, WI 53706 USA. RI Schmit, Timothy/F-5624-2010 NR 33 TC 73 Z9 75 U1 0 U2 2 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8763 J9 J APPL METEOROL JI J. Appl. Meteorol. PD MAY PY 1999 VL 38 IS 5 BP 501 EP 513 DI 10.1175/1520-0450(1999)038<0501:ANPRAI>2.0.CO;2 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 196CU UT WOS:000080292100001 ER PT J AU Berg, W Bates, JJ Jackson, DL AF Berg, W Bates, JJ Jackson, DL TI Analysis of upper-tropospheric water vapor brightness temperatures from SSM/T2, HIRS, and GMS-5 VISSR SO JOURNAL OF APPLIED METEOROLOGY LA English DT Article ID SATELLITE; RADIANCES; INFORMATION; SIMULATION; ALGORITHM; PROFILES; CLEAR AB Satellite microwave and infrared instruments sensitive to upper-tropospheric water vapor (UTWV) are compared using both simulated and observed cloud-cleared brightness temperatures (Tb's). To filter out cloudy scenes, a cloud detection algorithm is developed for the Special Sensor Microwave/Temperature-2 (SSM/T2 or T2) data using the 92- and 150-GHz window channels. An analysis of the effect of clouds on the T2 183-GHz channels shows sensitivity primarily to high clouds containing ice, resulting in significantly better sampling of UTWV Tb's over the convective zones and regions of persistent cloudiness. This is in contrast to the infrared sensors, which are extremely sensitive to any cloud contamination in the satellite field of view. A comparison of simulated UTWV Tb's from T2, the High-resolution Infrared Sounder (HIRS), and the Visible Infrared Spin Scan Radiometer (VISSR) indicates a higher overall sensitivity to changes in UTWV in the T2 channel. HIRS and VISSR, however, are more sensitive to moisture at higher levels. Cloud-cleared Tb's from T2 and HIRS were found to be highly correlated in the tropical dry zones and in regions of strong seasonal variability but less correlated at higher latitudes. The advantages of the microwave T2 sensor for monitoring UTWV are demonstrated by its greater sensitivity to changes in upper-tropospheric moisture and superior coverage over cloudy regions. C1 Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. NOAA, Climate Diagnost Ctr, Boulder, CO USA. RP Berg, W (reprint author), Univ Colorado, Cooperat Inst Res Environm Sci, Campus Box 216, Boulder, CO 80309 USA. RI Bates, John/D-1012-2009; Jackson, Darren/D-5506-2015 OI Bates, John/0000-0002-8124-0406; Jackson, Darren/0000-0001-5211-7866 NR 24 TC 15 Z9 15 U1 0 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 1999 VL 38 IS 5 BP 580 EP 595 DI 10.1175/1520-0450(1999)038<0580:AOUTWV>2.0.CO;2 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 196CU UT WOS:000080292100007 ER PT J AU Wang, Y Olthoff, JK AF Wang, Y Olthoff, JK TI Ion energy distributions in inductively coupled radio-frequency discharges in argon, nitrogen, oxygen, chlorine, and their mixtures SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID RF REFERENCE CELL; RADIOFREQUENCY REFERENCE CELL; HIGH-DENSITY PLASMA; ANGULAR-DISTRIBUTIONS; PARALLEL-PLATE; FLUXES; ATOMS AB We report ion energy distributions, relative ion intensities, and absolute total ion current densities at the grounded electrode of an inductively coupled Gaseous Electronics Conference radio-frequency reference cell for discharges generated in pure argon, nitrogen, oxygen, and chlorine, and in mixtures of argon with N-2,O-2, and Cl-2. Measured current densities are significantly greater for pure argon and for mixtures containing argon than for pure N-2,O-2, and Cl-2. For all three molecular gases, the ratio of molecular ions to the fragment ions decreases when argon is added to the molecular gas discharges. A possible destruction mechanism for the molecular ions involving metastable argon is discussed. (C) 1999 American Institute of Physics. [S0021-8979(99)00309-6]. C1 Natl Inst Stand & Technol, Div Elect, Elect & Elect Engn Lab, Gaithersburg, MD 20899 USA. RP Wang, Y (reprint author), Natl Inst Stand & Technol, Div Elect, Elect & Elect Engn Lab, Gaithersburg, MD 20899 USA. NR 23 TC 55 Z9 56 U1 2 U2 6 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD MAY 1 PY 1999 VL 85 IS 9 BP 6358 EP 6365 DI 10.1063/1.370138 PG 8 WC Physics, Applied SC Physics GA 188WA UT WOS:000079871200011 ER PT J AU Rust, WD Marshall, TC Stolzenburg, M Fitzgibbon, J AF Rust, WD Marshall, TC Stolzenburg, M Fitzgibbon, J TI Test of a GPS radiosonde in thunderstorm electrical environments SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article ID FIELD AB Meteorological radiosondes that use navigation systems to determine winds (and horizontal location) can be susceptible to data loss in thunderstorm environments. This paper reports on tests of a radiosonde that uses the Global Positioning System (GPS) for windfinding. Tests were made by flying the CPS radiosonde into three thunderstorms on free balloons that also carried an electric field meter and a long-range navigation (loran) radiosonde of a type previously tested. The GPS radiosonde performed without any significant loss of wind or thermodynamic data in in-storm maximum electric fields of up to -104 kV m (1). Also, no obvious deleterious effect on radiosonde data was found from the presence of nearby lightning. The radiosonde was further tested in a laboratory-produced electric field in an ambient atmospheric pressure of about 70 kPa, in which the radiosonde functioned normally in a vertical electric field up to 160 kV m(-1) and in a horizontal electric field up to 100 kV m(-1), the respective maximum applied. Radiosondes that were sprayed with water to simulate flight in rain performed correctly in an electric field of 135 kV m(-1)-the maximum that could be applied safely. The hypothesized reason for the excellent windfinding performance in high electric fields is paltry the very short antenna length needed for GPS reception. Other factors, which could not be assessed in this study, may include the inherent low-noise susceptibility of the GPS signals and the processing circuitry. The tests showed that the GPS radiosonde obtains wind data in larger electric fields than does the loran radiosonde. It is concluded that GPS radiosondes will acquire windfinding data in mot, if not all, thunderstorm and nonthunderstorm clouds that contain high electric fields. The thermodynamic data were also very good in the large electric fields. C1 NSSL, ERL, NOAA, Norman, OK 73019 USA. Univ Mississippi, Dept Phys & Astron, University, MS 38677 USA. NOAA, Natl Weather Serv, Field Syst Branch, Sensor Test Sect, Sterling, VA USA. RP Rust, WD (reprint author), NSSL, ERL, NOAA, 1313 Halley Circle, Norman, OK 73019 USA. OI Stolzenburg, Maribeth/0000-0001-8773-8101 NR 13 TC 2 Z9 3 U1 1 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 MAY PY 1999 VL 16 IS 5 BP 550 EP 560 DI 10.1175/1520-0426(1999)016<0550:TOAGRI>2.0.CO;2 PG 11 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA 194ZM UT WOS:000080224700005 ER PT J AU White, AB Senff, CJ Banta, RM AF White, AB Senff, CJ Banta, RM TI A comparison of mixing depths observed by ground-based wind profilers and an airborne lidar SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article ID CONVECTIVE BOUNDARY-LAYER AB The authors compare the mixing depths in the daytime convective boundary layers that were observed remotely by wind profilers and an airborne lidar during the 1995 Southern Oxidants Study. The comparison is used to determine whether the mixing depths deduced from radar reflectivity profiles measured by the wind profilers are the appropriate mixing depths to use in air pollution applications. The profiler mixing depth!: are based on evidence that the profile of the refractive index structure function parameter exhibits a peak at the boundary layer capping inversion. The lidar mixing depths are determined from the gradient in aerosol backscatter at the top of an aerosol mixing layer. The results of linear regression analysis show that the mixing depths measured by the wind profiler and lidar are in good agreement, particularly in the absence of scattered clouds forming at the top of the convective boundary layer. When significant cumulus convection occurs, the definition of mixing depth from both experimental and theoretical points of view is ill defined. C1 NOAA, ERL, ETL, RE ET7, Boulder, CO 80303 USA. Univ Colorado, NOAA, Environm Technol Lab, Boulder, CO 80309 USA. RP White, AB (reprint author), NOAA, ERL, ETL, RE ET7, 325 Broadway, Boulder, CO 80303 USA. RI White, Allen/A-7946-2009; Senff, Christoph/I-2592-2013; Banta, Robert/B-8361-2008 NR 16 TC 36 Z9 38 U1 0 U2 3 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0739-0572 J9 J ATMOS OCEAN TECH JI J. Atmos. Ocean. Technol. PD MAY PY 1999 VL 16 IS 5 BP 584 EP 590 DI 10.1175/1520-0426(1999)016<0584:ACOMDO>2.0.CO;2 PG 7 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA 194ZM UT WOS:000080224700008 ER PT J AU Groisman, PY Peck, EL Quayle, RG AF Groisman, PY Peck, EL Quayle, RG TI Intercomparison of recording and standard nonrecording US gauges SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article ID UNITED-STATES; REDUCING BIASES; PRECIPITATION; ACCURACY; ADJUSTMENTS; RAIN AB Existing adjustment procedures for precipitation measured by the 8-in. standard nonrecording rain gauge (SNRG) take into account gauge undercatch mostly due to wind-induced turbulence over its orifice. The goal of this paper is to "reduce" the measurements of the two most commonly used U.S. recording rain gauges (SRGs) to those for a hypothetical SNRG at the same site and use established relationship to adjust their readings to less biased values. This will allow gauge-specific adjustments for each gauge/precipitation type to secure less biased homogeneous precipitation time series and facilitate blending of precipitation information from different sources/networks. A significant portion of the U.S, rain gauges are automated recording gauges. A majority of the gauges of the National Oceanic and Atmospheric Administration Hourly Precipitation Network are unshielded Fischer and Porter recording rain gauges (FP) that have gradually replaced weighing recording rain gauges (WG). There are more than 1400 sites where the unshielded SNRG and FP are collocated (and more than 100 sites for SNRG and WG). Daily precipitation from these sites from 1982 to 1996 were partitioned into three categories: rainfall, frozen, and mixed precipitation. The hourly records from recording gauges were totaled over the 24-h-long period specific to each station to match the observation rimes of the SRGs and compared with the daily SNRG records. The comparison of the rain and snow catch of WG and SNRG shows nearly equivalent measurements. Mixed precipitation is the most troublesome type to register for WG and averages 7% less than collocated SNRG. Rain catch of the FP averages 5% less than SNRG and is not strongly related to climate conditions and/or surroundings of meteorological sites. Also, FP observations of frozen precipitation can be as high as 105% and as low as 70% compared to SNRG with an average of 90% (85% over the Great Plains). In open, windy locations, the SNRG can underestimate frozen precipitation by 50% or more. The authors' estimates indicate that FP underestimates frozen precipitation even more than SNRG, and the level of the underestimation is a function of wind speed and gauge exposure. C1 Natl Climat Data Ctr, Asheville, NC 28801 USA. HYDEX Corp, Alpine, UT USA. RP Groisman, PY (reprint author), Natl Climat Data Ctr, 151 Patton Ave, Asheville, NC 28801 USA. NR 40 TC 16 Z9 16 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 MAY PY 1999 VL 16 IS 5 BP 602 EP 609 DI 10.1175/1520-0426(1999)016<0602:IORASN>2.0.CO;2 PG 8 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA 194ZM UT WOS:000080224700011 ER PT J AU Tewari, YB Schantz, MM Vanderah, DJ AF Tewari, YB Schantz, MM Vanderah, DJ TI Thermodynamics of the lipase-catalyzed esterification of 1-dodecanoic acid with (-)-menthol in organic solvents SO JOURNAL OF CHEMICAL AND ENGINEERING DATA LA English DT Article ID EQUILIBRIUM POSITION; CANDIDA-CYLINDRACEA; RESOLUTION; MEDIA; MICROEMULSIONS; HYDROLYSIS; MENTHOL; SYSTEMS; WATER; ESTER AB The thermodynamics of the lipase-catalyzed stereospecific esterification of 1-dodecanoic acid with (-)-menthol in seven organic solvents have been investigated. Equilibrium measurements were performed using hexane, heptane, cyclohexane, toluene, 2,2,4-trimethylpentane, acetonitrile, and 2-methyl-2-butanol at the temperature T = 298.15 K. The equilibrium constants have been correlated with the (octanol + water) partition coefficients and the relative permittivities of the solvents. The saturation molalities and the (hexane + water) partition coefficients of (-)-menthol, 1-dodecanoic acid, and (-)-menthyl dodecanoate have also been determined at T = 298.15 K. The equilibrium constant of the esterification reaction in aqueous media has been calculated. An important finding is that the molality of water plays an important role in determining the extent of ester formation. Tn acetonitrile and 2-methyl-2-butanol, which have a very high molality of water, the formation of (-)-menthyl dodecanoate is considerably smaller. However, in hydrophobic solvents with lower molalities of water, the formation of (-)-menthyl dodecanoate is favored in the reaction mixture. The value of the equilibrium constant varies from 3 to 26. However, the molality of (-)-menthyl dodecanoate changes from 0.034 mmol kg(-1) in acetonitrile to 16 mmol kg(-1) in heptane. The change in product yield is a factor of approximate to 500 and is a striking example of the utility of organic solvents in biocatalysis. C1 Natl Inst Stand & Technol, Div Biotechnol, Gaithersburg, MD 20899 USA. Natl Inst Stand & Technol, Div Analyt Chem, Gaithersburg, MD 20899 USA. RP Tewari, YB (reprint author), Natl Inst Stand & Technol, Div Biotechnol, Gaithersburg, MD 20899 USA. NR 21 TC 18 Z9 18 U1 2 U2 6 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0021-9568 J9 J CHEM ENG DATA JI J. Chem. Eng. Data PD MAY-JUN PY 1999 VL 44 IS 3 BP 641 EP 647 DI 10.1021/je980299p PG 7 WC Thermodynamics; Chemistry, Multidisciplinary; Engineering, Chemical SC Thermodynamics; Chemistry; Engineering GA 200DV UT WOS:000080525100052 ER PT J AU Heller, SR AF Heller, SR TI Symantec Norton AntiVirus 5.0 for Windows SO JOURNAL OF CHEMICAL INFORMATION AND COMPUTER SCIENCES LA English DT Software Review C1 NIST, SRD, Gaithersburg, MD 20899 USA. RP Heller, SR (reprint author), NIST, SRD, 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 0095-2338 J9 J CHEM INF COMP SCI JI J. Chem. Inf. Comput. Sci. PD MAY-JUN PY 1999 VL 39 IS 3 BP 632 EP 632 DI 10.1021/ci990382w PG 1 WC Chemistry, Multidisciplinary; Computer Science, Information Systems; Computer Science, Interdisciplinary Applications SC Chemistry; Computer Science GA 200DT UT WOS:000080524900029 ER PT J AU Heller, SR AF Heller, SR TI Norton 2000 version 1.0 for Windows SO JOURNAL OF CHEMICAL INFORMATION AND COMPUTER SCIENCES LA English DT Software Review C1 NIST, Gaithersburg, MD 20899 USA. RP Heller, SR (reprint author), NIST, Gaithersburg, MD 20899 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0095-2338 J9 J CHEM INF COMP SCI JI J. Chem. Inf. Comput. Sci. PD MAY-JUN PY 1999 VL 39 IS 3 BP 633 EP 633 DI 10.1021/ci9903814 PG 1 WC Chemistry, Multidisciplinary; Computer Science, Information Systems; Computer Science, Interdisciplinary Applications SC Chemistry; Computer Science GA 200DT UT WOS:000080524900030 ER PT J AU Chapman, WB Kulcke, A Blackmon, BW Nesbitt, DJ AF Chapman, WB Kulcke, A Blackmon, BW Nesbitt, DJ TI Rotationally inelastic scattering of jet cooled H2O with Ar: State-to-state cross sections and rotational alignment effects SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID POTENTIAL-ENERGY SURFACES; INFRARED-LASER SPECTROSCOPY; MOLECULAR-BEAM SCATTERING; SUPERSONIC JETS; ANISOTROPIC INTERACTION; VANDERWAALS BONDS; TUNNELING SPECTRA; IR ABSORPTION; AR-H2O; EXCITATION AB State-to-state rotationally inelastic scattering cross sections of H2O with Ar are measured under single-collision conditions in crossed supersonic jets at a collision energy of 480(90) cm(-1). The H2O is initially prepared in its lowest ortho (1(01)) and para (0(00)) rotational levels by supersonic cooling in a Ne expansion, and then excited in the intersection region by single collisions with a second pulsed jet of Ar atoms. Column-integrated densities of H2O in both initial and final scattering states are monitored via direct absorption of narrow bandwidth (Delta nu approximate to 0.0001 cm(-1)) infrared light from a continuous wave (cw) F-center laser. Absolute inelastic cross sections for state-to-state collisional energy transfer out of para and ortho initial states are determined from the dependence of infrared absorption signals on collider gas densities. Overall, the results can be approximately characterized by an exponential decrease in cross section with the magnitude of rotational energy transferred, i.e., as suggested by exponential energy gap models. However, at the state-to-state level, a highly structured, nonmonotonic dependence on energy is observed, which indicates a propensity for rotational excitation around the A (in-plane, perpendicular to C-2) and C (out-of-plane) principal axes. This preferential state-to-state scattering dynamics reflects an intramolecular alignment of J in the body-fixed frame and is in good qualitative agreement with theoretical classical trajectory predictions. A rigorous comparison is made via full quantum close-coupling scattering calculations on empirical and ab initio Ar-H2O potential energy surfaces, which successfully reproduce all the state-to-state trends observed, but at the more quantitative level appear to overestimate the intramolecular alignment effects experimentally observed. (C) 1999 American Institute of Physics. [S0021-9606(99)01517-2]. C1 Natl Inst Stand & Technol, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. Univ Colorado, Dept Chem & Biochem, Boulder, CO 80309 USA. RP Chapman, WB (reprint author), Natl Inst Stand & Technol, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. NR 56 TC 21 Z9 21 U1 0 U2 7 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD MAY 1 PY 1999 VL 110 IS 17 BP 8543 EP 8554 DI 10.1063/1.478762 PG 12 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 189PD UT WOS:000079913000036 ER PT J AU Votava, O Plusquellic, DF Nesbitt, DJ AF Votava, O Plusquellic, DF Nesbitt, DJ TI Vibrationally mediated photolysis dynamics of H2O in the v(OH)=3 manifold: Far off resonance photodissociation cross sections and OH product state distributions SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID 1ST ABSORPTION-BAND; POTENTIAL-ENERGY SURFACES; RESOLVED PHOTODISSOCIATION; EXCITED WATER; MOLECULES; ROTATIONS; ABINITIO; D2O; HOD AB Vibrationally mediated photodissociation dynamics of water on the first excited electronic state surface ((A) over tilde) has been studied with slit jet-cooled H2O prepared in the complete polyad of upsilon(OH) = 3 overtone stretch levels (\03(+)], \12(+)], \12(-)], and \03(-)]). (Notationally, \n(1)n(2)(+/-)] refers to symmetric/antisymmetric combinations of local mode OH stretch excitation, roughly corresponding to n(1) and n(2) quanta in the spectator and photolyzed OH bond, respectively.) At 248 nm photolysis wavelength the Condon point for bond cleavage occurs in the classically forbidden region, primarily sampling highly asymmetric H + OH exit valley geometries of the potential energy surface. Rotational, vibrational, spin orbit, and lambda doublet distributions resulting from this "far off resonance'' photodissociation process are probed via laser induced fluorescence, exploiting the high efficiency laser excitation and light collection properties of the slit jet expansion geometry. Only vibrationally unexcited OH products are observed for both \12+/-] and \03(+/-)] initial excitation of H2O, despite different levels of vibration in the spectator OH bond. This is in contrast with "near-resonance'' vibrationally mediated photolysis studies by Crim and co-workers in the \04(-)] and \13(-)] manifold, but entirely consistent with theoretical predictions from a simple two-dimensional quantum model. Photolysis out of the rotational ground H2O state (i. e., J(KaKc) = 0(00)) yields OH product state distributions that demonstrate remarkable insensitivity to the initial choice of H2O vibrational stretch state, in good agreement with rotational Franck-Condon models. However, this simple trend is not followed uniformly for rotationally excited H2O precursors, which indicates that these Franck-Condon models are insufficient and suggests that exit channel interactions do play a significant role in photodissociation dynamics of H2O at the fully state-to-state level. (C) 1999 American Institute of Physics. [S0021-9606(99)00517-6]. C1 Natl Inst Stand & Technol, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. Univ Colorado, Dept Chem & Biochem, Boulder, CO 80309 USA. Natl Inst Stand & Technol, Quatum Phys Div, Boulder, CO 80309 USA. RP Votava, O (reprint author), Natl Inst Stand & Technol, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. NR 29 TC 16 Z9 16 U1 0 U2 8 PU AMER INST PHYSICS PI WOODBURY PA CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD MAY 1 PY 1999 VL 110 IS 17 BP 8564 EP 8576 DI 10.1063/1.478764 PG 13 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 189PD UT WOS:000079913000038 ER PT J AU Gallo, KP Owen, TW Easterling, DR Jamason, PF AF Gallo, KP Owen, TW Easterling, DR Jamason, PF TI Temperature trends of the U.S. historical climatology network based on satellite-designated land use/land cover SO JOURNAL OF CLIMATE LA English DT Article ID CITY LIGHTS; URBAN AB The 1221 weather observation stations that compose the U.S. Historical Climatology Network were designated as either urban, suburban, or rural based on data from the Defense Meteorological Satellite Program Operational Linescan System (OLS). The designations were based on local and regional samples of the OLS data around the stations (OLS method). Trends in monthly maximum and minimum temperature and the diurnal temperature range (DTR) were determined for the 1950-96 interval for each of three land use/land cover (LULC) designations. The temperature trends for the OLS-derived designations of LULC were compared to similarly designated LULC based on (i) map- (Operational Navigation Charts) and population-based estimates of LULC (ONCP method), and (ii) LULC designations that resulted from of a survey of the network station operators. Although differences were not statistically significant, the DTR trends (degrees Celsius per 100 years)did differ between the LULC classes defined by the OLS method, from -0.41 for the rural stations to -0.86 for the urban stations. Trends also differed, although not significantly, between the methods used to define an LULC class, such that the trends in rural DTR varied from -0.41 for the OLS defined stations to -0.67 for the ONCP defined stations. Although the trends between classes were not significantly different, they do present some contrasts that might confound the interpretation of temperature trends when the local and regional environments associated with the analyzed stations are not considered. The general (urban, suburban, or rural) LULC associated with surface observation stations appears to be one of the factors that can influence the trends observed in temperatures and thus should be considered in the analysis and interpretation of temperature trends. C1 Natl Climate Data Ctr, Asheville, NC 28801 USA. NOAA, Natl Environm Satellite Data & Informat Serv, Off Res & Applicat, Washington, DC 20233 USA. Univ Calif San Diego, Scripps Inst Oceanog, La Jolla, CA 92093 USA. RP Gallo, KP (reprint author), Natl Climate Data Ctr, 151 Patton Ave, Asheville, NC 28801 USA. RI Gallo, Kevin P./F-5588-2010 NR 16 TC 81 Z9 96 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 MAY PY 1999 VL 12 IS 5 BP 1344 EP 1348 DI 10.1175/1520-0442(1999)012<1344:TTOTUS>2.0.CO;2 PN 1 PG 5 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 193PQ UT WOS:000080145600013 ER PT J AU Peng, SL Whitaker, JS AF Peng, SL Whitaker, JS TI Mechanisms determining the atmospheric response to midlatitude SST anomalies SO JOURNAL OF CLIMATE LA English DT Article ID SEA-SURFACE TEMPERATURE; DECADAL CLIMATE VARIABILITY; GENERAL-CIRCULATION MODEL; NORTH PACIFIC; ATLANTIC; OCEAN; FREQUENCY; GCM; DEPENDENCE; DYNAMICS AB Previous GCM experiments demonstrated that a model atmosphere produces two different responses to a midlatitude warm SST anomaly over the Pacific under perpetual January and February conditions. To elucidate the mechanisms responsible for the different GCM responses and their dependence on the background How, experiments with two idealized models are conducted. Experiments with a linear baroclinic model reveal that the GCM responses at equilibrium are primarily maintained by the anomalous eddy forcing. The anomalous Bow induced directly by an idealized initial heat source exhibits little sensitivity to the background How. Eddy feedbacks on the heating-induced anomalous flow are examined using a linear storm track model. The anomalous eddy Forcing produced by the storm track model is sensitive to the basic state. The eddy forcing in January acts to shift the heating-induced upper-level ridge toward the northeast of the Gulf of Alaska, while in February it acts to reinforce the ridge. This suggests that the differences in the GCM; responses are primarily associated with differences in the response of synoptic eddies to the presence of an anomalous ridge at the end of the Pacific storm track. The idealized model experiments are also performed with the observed winter mean flow. The eddy feedbacks depend on the position of the heating relative to the storm track. With the heating centered over the western Pacific the eddy-driven anomalous flow reinforces the ridge over the Pacific, similar to that in GCM February, but much stronger. No such reinforcement by the transients is found with the heating shifted over the eastern Pacific. These results suggest that SST anomalies over the western Pacific perhaps play a more active role in midlatitude atmosphere-ocean interactions. C1 NOAA, CIRES, CDC, R,E,CDI, Boulder, CO 80303 USA. RP Peng, SL (reprint author), NOAA, CIRES, CDC, R,E,CDI, 325 Broadway, Boulder, CO 80303 USA. NR 26 TC 170 Z9 177 U1 2 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 PY 1999 VL 12 IS 5 BP 1393 EP 1408 DI 10.1175/1520-0442(1999)012<1393:MDTART>2.0.CO;2 PN 2 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 193PR UT WOS:000080145700004 ER PT J AU Overland, JE Adams, JM Bond, NA AF Overland, JE Adams, JM Bond, NA TI Decadal variability of the Aleutian low and its relation to high-latitude circulation SO JOURNAL OF CLIMATE LA English DT Article ID NORTHERN-HEMISPHERE; GEOPOTENTIAL HEIGHT; SEA-ICE; PACIFIC; TEMPERATURE; OSCILLATION; TELECONNECTIONS; DECREASE; AMERICA; WINTER AB The January-February mean central pressure of the Aleutian low is investigated as an index of North Pacific variability on interannual to decadal timescales. Since the turn of the century, 37% of the winter interannual variance of the Aleutian low is on timescales greater than 5 yr. An objective algorithm detects zero crossings of Aleutian low central pressure anomalies in 1925, 1931, 1939, 1947, 1959, 1968, 1976, and 1989. No single midtropospheric teleconnection pattern is sufficient to capture the variance of the Aleutian low. The Aleutian low covaries primarily with the Pacific-North American (PNA) pattern but also with the Arctic Oscillation (AO). The change to a prominent deep Aleutian low after 1977 is seen in indices of both the PNA and AO; the return to average conditions after 1989 was also associated with a change in the AO. The authors' analysis suggests an increasing covariability of the high- and midlatitude atmosphere after 1970. C1 NOAA, Pacific Marine Environm Lab, Seattle, WA 98115 USA. Univ Washington, Joint Inst Study Atmosphere & Oceans, Seattle, WA 98195 USA. RP Overland, JE (reprint author), NOAA, Pacific Marine Environm Lab, 7600 Sand Point Way Ne, Seattle, WA 98115 USA. NR 30 TC 225 Z9 239 U1 2 U2 32 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 PY 1999 VL 12 IS 5 BP 1542 EP 1548 DI 10.1175/1520-0442(1999)012<1542:DVOTAL>2.0.CO;2 PN 2 PG 7 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 193PR UT WOS:000080145700014 ER PT J AU Riley, P Gosling, JT McComas, DJ Pizzo, VJ Luhmann, JG Biesecker, D Forsyth, RJ Hoeksema, JT Lecinski, A Thompson, BJ AF Riley, P Gosling, JT McComas, DJ Pizzo, VJ Luhmann, JG Biesecker, D Forsyth, RJ Hoeksema, JT Lecinski, A Thompson, BJ TI Relationship between Ulysses plasma observations and solar observations during the Whole Sun Month campaign SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID HELIOSPHERIC CURRENT SHEET; WIND VARIABILITY; LATITUDES; MISSION; STREAM; MODELS; BAND AB In this report, we summarize measurements made by the plasma experiment on the Ulysses spacecraft during the period designated as "Whole Sun Month" (WSM, August 10 to September 8; 1996). This interval coincided with the return of solar wind variability at Ulysses. Ulysses was located at similar to 28 degrees N heliographic latitude, at a heliocentric distance of 4.25 AU, and on the opposite side of the Sun from Earth. In particular: we explore the evolution of the solar wind between the Sun and Ulysses for several rotations surrounding WSM. Specifically, we map Ulysses measurements back toward the Sun by applying a two-dimensional inverse MHD algorithm. This approach is compared with the commonly used constant speed (or ballistic) approximation. We find that the MHD mapping technique produces substantially better results when compared with solar observations. Both the Ulysses MHD-mapped results and the solar observations are consistent with a picture of a modestly tilted streamer belt (< 10 degrees) that was deformed northward by an active region at 240 degrees - 270 degrees longitude. C1 ScriberNet Inc, San Diego, CA 92121 USA. Univ Calif Los Alamos Natl Lab, Space & Atmospher Sci Grp, Los Alamos, NM 87545 USA. NOAA, Space Environm Lab, Boulder, CO 80303 USA. Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. Univ Birmingham, Sch Phys & Space Res, Birmingham B15 2TT, W Midlands, England. Univ London Imperial Coll Sci Technol & Med, Blackett Lab, London SW7 2BZ, England. Stanford Univ, Wilcox Solar Observ, Ctr Astrophys & Space Sci, Hansen Expt Phys Lab, Stanford, CA 94305 USA. Natl Ctr Atmospher Res, High Altitude Observ, Boulder, CO 80307 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Riley, P (reprint author), Sci Applicat Int Corp, San Diego, CA 92121 USA. RI Thompson, Barbara/C-9429-2012 NR 23 TC 23 Z9 23 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 MAY 1 PY 1999 VL 104 IS A5 BP 9871 EP 9879 DI 10.1029/1998JA900078 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 192BQ UT WOS:000080058600017 ER PT J AU Viereck, RA Puga, LC AF Viereck, RA Puga, LC TI The NOAA Mg II core-to-wing solar index: Construction of a 20-year time series of chromospheric variability from multiple satellites SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID IRRADIANCE COMPARISON EXPERIMENT-1; BACKSCATTER ULTRAVIOLET; STRATOSPHERIC OZONE; UARS; TEMPERATURE; SOLSTICE; MONITOR; CLIMATE; SBUV/2 AB The Mg II core-to-wing ratio is a measure of the amplitude of the chromospheric Mg II ion emission at 280 nm. It has been shown to have strong correlation with solar UV (150 - 400 nm) irradiance and other measures of solar activity and is relatively insensitive to errors introduced by variations in instrument sensitivity. For these reasons, the Mg II core-to-wing ratio has been used as a proxy for solar activity. Observations of the Mg II ratio started with the Solar Backscattered Ultraviolet spectrograph (SBUV) instrument on the Nimbus 7 spacecraft in November 1978. Since then, SBUV and SBUV2 instruments have flown regularly on the NOAA series of polar orbiting spacecraft, providing a nearly continuous set of daily solar observations. Measurements of the solar UV irradiance made from NOAA satellites ended in February 1998 when the NOAA9 satellite failed. Because it had been operating for nearly 12 years (at least 7 years beyond its expected lifetime), the NOAA 9 SBUV2 showed significant degradation near the end of its life. The most recent data required significantly more attention to extract the Mg II core-to-wing ratio. There have also been data gaps that require the augmentation of data from other sources. In particular, data from the UARS Solar Stellar Irradiance Comparison Experiment (SOLSTICE) instrument was used to bridge a 5 month gap in 1995. In this report we combine data from four different instruments to create the longest and most complete record of the Mg II core-to-wing ratio to date. We describe a modified analysis procedure that has allowed us to extend the Mg II index up to the beginning of 1998. Finally, we compare the time series of the Mg II ratio to similar measurements from the Solar Ultraviolet Spectral Irrandiance Monitor (SUSIM) instrument to determine the quality of the NOAA Mg II core-to-wing data set. C1 NOAA, ERL, NCEP, Space Environm Ctr, Boulder, CO 80303 USA. RP Viereck, RA (reprint author), NOAA, ERL, NCEP, Space Environm Ctr, 325 Broadway, Boulder, CO 80303 USA. NR 25 TC 81 Z9 82 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD MAY 1 PY 1999 VL 104 IS A5 BP 9995 EP 10005 DI 10.1029/1998JA900163 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 192BQ UT WOS:000080058600029 ER PT J AU Ahn, BH Emery, BA Kroehl, HW Kamide, Y AF Ahn, BH Emery, BA Kroehl, HW Kamide, Y TI Climatological characteristics of the auroral ionosphere in terms of electric field and ionospheric conductance SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article ID GEOMAGNETIC INDEXES; COUPLING FUNCTION; CHATANIKA RADAR; CURRENT SYSTEMS; CONVECTION; SUBSTORMS; PATTERNS; CONDUCTIVITY; ENERGY; POTENTIALS AB The contributions of the north-south component of the electric field and the Hall conductance to the auroral electrojet are examined separately. For this purpose, 52 days of measurements from the Chatanika incoherent scatter radar, which was located near one of the standard AE stations, College, are utilized. A number of interesting characteristics of the auroralelectrojet system and auroral electrojet indices are noted: (1) The electric field distribution along the auroral region is roughly symmetric with respect to the 1100-2300 magnetic local time meridian. (2) The electric field, particularly the southward component, becomes a dominant feature along auroral latitudes with increasing magnetic activity. (3) The Hall conductance distribution in the postnoon sector is mainly determined by the Sun, thus making the eastward electrojet and the AU index dependent upon season. On the other hand, the Hall conductance associated with the major part of the westward electrojet in the midnight-postmidnight sector is controlled by precipitating electrons. (4) Since the Hall conductance of solar origin in the postnoon sector can be estimated, it would be possible to monitor electric field enhancements contributing to the eastward electrojet. By assuming the same electric field, except for the sign being applied to the westward electrojet, the AL index can be used to estimate the contribution of the Hall conductance associated with particle precipitation. This is a clear indication that the two indices, AU and AL, are governed by different physical processes. Thus it is recommended to use the two indices separately, rather than the combined AE, in monitoring the auroral electrojet system. (5) The Harang discontinuity seems to be a boundary separating the region of precipitating energetic particles on its northeast side from that of soft particles on its southwest side. C1 Kyungpook Natl Univ, Dept Earth Sci, Taegu 702701, South Korea. Natl Ctr Atmospher Res, High Altitude Observ, Boulder, CO 80307 USA. NOAA, Natl Geophys Data Ctr, Boulder, CO 80303 USA. Nagoya Univ, Solar Terr Environm Lab, Toyokawa 442, Japan. RP Ahn, BH (reprint author), Kyungpook Natl Univ, Dept Earth Sci, Taegu 702701, South Korea. NR 42 TC 17 Z9 17 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD MAY 1 PY 1999 VL 104 IS A5 BP 10031 EP 10040 DI 10.1029/1999JA900043 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 192BQ UT WOS:000080058600032 ER PT J AU Coffey, HE AF Coffey, HE TI Geomagnetic and solar data SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Editorial Material C1 NOAA, World Data Ctr Solar Terr Phys A, Boulder, CO 80303 USA. RP Coffey, HE (reprint author), NOAA, World Data Ctr Solar Terr Phys A, 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 MAY 1 PY 1999 VL 104 IS A5 BP 10381 EP 10381 DI 10.1029/1999JA900131 PG 1 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 192BQ UT WOS:000080058600063 ER PT J AU Rocha-Olivares, A Rosenblatt, RH Vetter, RD AF Rocha-Olivares, A Rosenblatt, RH Vetter, RD TI Cryptic species of rockfishes (Sebastes : Scorpaenidae) in the Southern Hemisphere inferred from mitochondrial lineages SO JOURNAL OF HEREDITY LA English DT Article ID DNA-SEQUENCES AB We used mitochondrial DNA sequence variation of Sebastes from the southeastern Pacific and three localities in the South Atlantic to address long-standing systematic and evolutionary issues regarding the number of species in the Southern Hemisphere. Sequences of the hypervariable mitochondrial control region were obtained from 10 specimens of S. capensis from South Africa (n = 5) and from Tristan da Cunha Island (n = 5) and 27 of S. oculatus from Valparaiso, Chile (n = 10), and the Falkland Islands (n = 17), Results of the study include (1) significant levels of genetic differentiation among the sampled populations (Phi(ST) = 0.225, P < .000001), thus indicating limited gene flow; (2) corroboration of the existence of two different lineages of austral Sebastes corresponding to S. capensis and S. oculatus; (3) finding that S. capensis is not restricted to Tristan da Cunha and South Africa, but is widespread across the South Atlantic; (4) the position of S. capensis as the ancestral lineage of the austral Sebastes; (5) the existence of a third evolutionary lineage with high levels of genetic divergence, particularly abundant in the southwestern Atlantic, which may be recognized as a third austral species of Sebastes. C1 Univ Calif San Diego, Scripps Inst Oceanog, La Jolla, CA 92093 USA. NOAA, SW Fisheries Sci Ctr, La Jolla, CA USA. RP Rocha-Olivares, A (reprint author), Louisiana State Univ, Dept Biol Sci, 508 Life Sci Bldg, Baton Rouge, LA 70809 USA. RI Rocha-Olivares, Axayacatl/A-9832-2008 OI Rocha-Olivares, Axayacatl/0000-0002-2700-9086 NR 29 TC 46 Z9 47 U1 0 U2 2 PU OXFORD UNIV PRESS INC PI CARY PA JOURNALS DEPT, 2001 EVANS RD, CARY, NC 27513 USA SN 0022-1503 J9 J HERED JI J. Hered. PD MAY-JUN PY 1999 VL 90 IS 3 BP 404 EP 411 DI 10.1093/jhered/90.3.404 PG 8 WC Evolutionary Biology; Genetics & Heredity SC Evolutionary Biology; Genetics & Heredity GA 206CK UT WOS:000080858700015 PM 10355124 ER PT J AU Rochford, KB Dyer, SD AF Rochford, KB Dyer, SD TI Demultiplexing of interferometrically interrogated fiber Bragg grating sensors using Hilbert transform processing SO JOURNAL OF LIGHTWAVE TECHNOLOGY LA English DT Article DE Hilbert transforms; interferometry; optical fiber; sensor; wavelength division multiplexing (WDM); wavelength measurement AB The peak reflectance wavelengths of gratings with reflectance maxima separated by less than 2 nm can be accurately determined through a demultiplexing method based on Hilbert transforms of interferograms. We demonstrate a wavelength demultiplexing of three fiber Bragg gratings (FBG's) with less than 4 pm crosstalk and repeatability and less than 19 pm uncertainty. We anticipate that a large number of gratings can be demultiplexed with a single broadband source and a single receiving interferometer, provided that the interferogram is sampled at accurate intervals slightly above the Nyquist rate. C1 Natl Inst Stand & Technol, Div Optoelect, Boulder, CO 80303 USA. RP Rochford, KB (reprint author), Natl Inst Stand & Technol, Div Optoelect, 325 Broadway, Boulder, CO 80303 USA. NR 8 TC 21 Z9 21 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 0733-8724 J9 J LIGHTWAVE TECHNOL JI J. Lightwave Technol. PD MAY PY 1999 VL 17 IS 5 BP 831 EP 836 DI 10.1109/50.762900 PG 6 WC Engineering, Electrical & Electronic; Optics; Telecommunications SC Engineering; Optics; Telecommunications GA 194QJ UT WOS:000080204800013 ER PT J AU Huck, T Weaver, AJ de Verdiere, AC AF Huck, T Weaver, AJ de Verdiere, AC TI On the influence of the parameterization of lateral boundary layers on the thermohaline circulation in coarse-resolution ocean models SO JOURNAL OF MARINE RESEARCH LA English DT Article ID MESOSCALE TRACER TRANSPORTS; THERMOCLINE MODEL; HEAT-TRANSPORT; ATLANTIC-OCEAN; WORLD OCEAN; DRIVEN; DIFFUSION; WATER; WIND; SENSITIVITY AB Because of the first order geostrophic balance in the ocean interior, the parameterization of lateral boundary layers has more influence than the parameterization of viscosity on the thermohaline overturning and the deep water properties in coarse-resolution ocean circulation models. Different formulations of momentum dissipation and associated boundary conditions are implemented within a planetary-geostrophic ocean circulation model for a Cartesian coordinate, flat-bottomed, beta-plane, with restoring boundary conditions for the surface density and zero wind stress. Traditional Laplacian friction with a no-slip boundary condition produces an interior circulation in good agreement with geostrophy and the Sverdrup balance, but generates very large vertical (diapycnal) transports at lateral boundaries, especially upwelling in the western boundary current and downwelling in the northeast corner. The meridional and zonal overturning are thus enhanced, but drive to depth surface waters that are not as cold as the ones in the deep convection regions. Rayleigh friction with various frictional closures for the alongshore velocities within a no-normal-flow boundary condition framework efficiently reduces the diapycnal vertical transports along the boundaries, by allowing horizontal recirculation of geostrophic currents impinging into coasts. Hence, these parameterizations induce weaker overturnings, with colder deep water and a sharper thermocline resulting in higher poleward heat transports. We suggest that the upwelling along the boundaries is a consequence of the coarse-resolution dynamics and not only horizontal diffusion (termed the "Veronis effect," horizontal diffusion produces large diapycnal fluxes once the isopycnals are tilted by coastal upwellings). Alternative parameterizations for the lateral boundary layers reduce this effect without the need for rotating the mixing tensor along isopycnals. This model comparison proves the need to clearly assess the extent of the diapycnal upwelling in the western boundary currents and to develop physically-based parameterizations of lateral boundary layers in order to improve coarse-resolution OGCMs. C1 Univ Victoria, Sch Earth & Ocean Sci, Victoria, BC V8W 3P6, Canada. Univ Bretagne Occidentale, Lab Phys Oceans, F-29285 Brest, France. RP Huck, T (reprint author), Princeton Univ, Geophys Fluid Dynam Lab, Program Atmospher & Ocean Sci, Forrestal Campus Route 1, Princeton, NJ 08542 USA. RI Weaver, Andrew/E-7590-2011; Huck, Thierry/L-5549-2015 OI Huck, Thierry/0000-0002-2885-5153 NR 62 TC 22 Z9 22 U1 0 U2 3 PU KLINE GEOLOGY LABORATORY PI NEW HAVEN PA YALE UNIV, NEW HAVEN, CT 06520-8109 USA SN 0022-2402 J9 J MAR RES JI J. Mar. Res. PD MAY PY 1999 VL 57 IS 3 BP 387 EP 426 DI 10.1357/002224099764805138 PG 40 WC Oceanography SC Oceanography GA 212JH UT WOS:000081213200001 ER PT J AU Wong-Ng, W Cook, LP Greenwood, W AF Wong-Ng, W Cook, LP Greenwood, W TI Effect of Po-2 and Ag on the phase formation of the Bi(Pb)-2223 superconductor SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID CU-O SYSTEM; OXYGEN PARTIAL-PRESSURE; HIGH-TC PHASE; COMPOSITE CONDUCTORS; GLASS-CERAMICS; CLAD (BI; CA-RICH; SILVER; TEMPERATURE; MECHANISM AB The chemical reactions and the compositional characteristics of liquids which lead to the phase formation of the Bi(Pb)-2223 [(Bi, Pb) : Sr:Ca: Cu: O] superconductor have been studied for a precursor composition of Bi1.8Pb0.4Sr2Ca2.2Cu3Ox The combined techniques of quenching, powder x-ray diffraction, differential thermal/thermogravimetric analysis (DTA/TGA), scanning electron microscopy (SEM), and energy dispersive x-ray spectroscopy (EDS) were used to characterize the subsolidus phases and the presence of liquid. Samples were annealed under purified air and under a volume fraction mixture of 7.5% O-2/92.5% Ar. The effects of Ag in both the pure air and the 7.5% O-2/92.5% Ar experiments were also studied. Results are discussed with respect to their processing implications. C1 Natl Inst Stand & Technol, Div Ceram, Gaithersburg, MD 20899 USA. Univ Maryland, Dept Geol, College Pk, MD 20742 USA. RP Wong-Ng, W (reprint author), Natl Inst Stand & Technol, Div Ceram, Gaithersburg, MD 20899 USA. NR 55 TC 18 Z9 18 U1 0 U2 3 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 MAY PY 1999 VL 14 IS 5 BP 1695 EP 1706 DI 10.1557/JMR.1999.0230 PG 12 WC Materials Science, Multidisciplinary SC Materials Science GA 235PD UT WOS:000082550500006 ER PT J AU Bonevich, J van Heerden, D Josell, D AF Bonevich, J van Heerden, D Josell, D TI Face-centered-cubic titanium: An artifact in titanium/aluminum multilayers SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID FCC TITANIUM; ALUMINUM MULTILAYERS; THIN-FILMS AB The present investigation is the first comprehensive comparative study of x-ray diffraction (XRD) and transmission electron microscopy (TEM) results to address the important issue of fee Ti formation in nanoscale multilayers, Ti/Al multilayers with 7.2 and 5.2 nm composition modulation wavelengths were studied by reflection and transmission XRD as well as transmission electron diffraction (ED), high-resolution TEM, and energy-filtered TEM. Previous reports have claimed deposition of fee Ti in multilayer systems. Our results demonstrate that the Ti in Ti/Al multilayers deposits in the hcp form and that fee Ti is merely an artifact of producing specimens for cross-sectional TEM. C1 Natl Inst Stand & Technol, Div Met, Gaithersburg, MD 20899 USA. Johns Hopkins Univ, Dept Mat Sci, Baltimore, MD 21218 USA. RP Bonevich, J (reprint author), Natl Inst Stand & Technol, Div Met, Gaithersburg, MD 20899 USA. NR 13 TC 17 Z9 18 U1 0 U2 1 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 MAY PY 1999 VL 14 IS 5 BP 1977 EP 1981 DI 10.1557/JMR.1999.0266 PG 5 WC Materials Science, Multidisciplinary SC Materials Science GA 235PD UT WOS:000082550500042 ER PT J AU Huck, T De Verdiere, AC Weaver, AJ AF Huck, T De Verdiere, AC Weaver, AJ TI Interdecadal variability of the thermohaline circulation in box-ocean models forced by fixed surface fluxes SO JOURNAL OF PHYSICAL OCEANOGRAPHY LA English DT Article ID FRESH-WATER FLUX; GENERAL-CIRCULATION; NORTH-ATLANTIC; PARAMETER SENSITIVITY; ATMOSPHERE MODEL; HEAT-FLUX; CONVECTIVE-ADJUSTMENT; CLIMATE VARIABILITY; DECADAL VARIABILITY; BOUNDARY-LAYER AB Intrinsic modes of decadal variability are analyzed using box-geometry ocean models forced by constant surface fluxes. An extensive parameter sensitivity analysis of the oscillatory behavior is carried out with respect to the spherical/Cartesian geometry, the beta effect, the Coriolis parameter the parameterization of momentum dissipation and associated boundary conditions, the vertical and horizontal diffusivities, the convective adjustment algorithm, the horizontal and vertical model resolution, the forcing amplitude, and the basin width. The oscillations stand out as a robust geostrophic feature whose amplitude is mainly controlled by the horizontal diffusivity. Unsuccessful attempts to reproduce the variability in zonally averaged 2D models suggest that the 3D adjustment processes are necessary. However, the beta effect is not necessary for decadal variability to occur, and therefore classical Rossby waves play no fundamental role in the mechanism. Various experiments with different geometry and forcing are conducted and do not support the necessity of viscous numerical boundary waves or any boundary in sustaining the oscillations. The models show two types of oscillatory behavior: 1) temperature anomalies propagating geostrophically westward in the eastward jet (northern parr of the basin) and inducing an opposite anomaly in their wake and 2) stationary temperature anomalies in the northwest quarter that respond to the western boundary current transport changes and reinforce geostrophically this change until the opposite temperature anomaly built on the east finally reverses the meridional overturning anomaly. The analysis of the transition from steady to oscillatory states (using heat fluxes diagnosed at the equilibrium under restoring boundary conditions) and the comparison of the variability under various forcing fields suggest that the oscillations are triggered in the regions of strongest surface cooling. Finally, a simple box-model analogy is proposed that captures the crucial phase shift between meridional overturning and north-south density gradient anomalies on these decadal timescales. C1 Univ Bretagne Occidentale, Lab Phys Oceans, Brest, France. Univ Victoria, Sch Earth & Ocean Sci, Victoria, BC, Canada. RP Huck, T (reprint author), Princeton Univ, GFDL, Forrestal Campus Route 1, Princeton, NJ 08542 USA. RI Weaver, Andrew/E-7590-2011; Huck, Thierry/L-5549-2015 OI Huck, Thierry/0000-0002-2885-5153 NR 64 TC 57 Z9 58 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-3670 J9 J PHYS OCEANOGR JI J. Phys. Oceanogr. PD MAY PY 1999 VL 29 IS 5 BP 865 EP 892 DI 10.1175/1520-0485(1999)029<0865:IVOTTC>2.0.CO;2 PG 28 WC Oceanography SC Oceanography GA 200WW UT WOS:000080563900002 ER PT J AU Yu, X McPhaden, MJ AF Yu, X McPhaden, MJ TI Seasonal variability in the equatorial Pacific SO JOURNAL OF PHYSICAL OCEANOGRAPHY LA English DT Article ID SEA-SURFACE TEMPERATURE; ANNUAL ROSSBY-WAVE; TROPICAL PACIFIC; ANNUAL CYCLE; OCEAN CIRCULATION; ENSO PREDICTION; EL-NINO; MODEL; ATMOSPHERE; CURRENTS AB Five to nine years of observations from the Tropical Atmosphere Ocean array in the tropical Pacific are used to document the seasonal cycle of surface winds, zonal currents, SST, thermocline depth, and dynamic height. Along the equator, the normally westward surface zonal current reverses direction in late boreal spring and early summer. This seasonal variation in the zonal surface current propagates westward, as do seasonal variations in the Equatorial Undercurrent and zonal surface winds at the equator. At 5 degrees N and 5 degrees S, the seasonal variations in the 20 degrees C isotherm and dynamic height also propagate westward. Conversely at the equator in the eastern and central Pacific, the variations in 20 degrees C isotherm depth and dynamic height propagate eastward. These seasonal variations are interpreted by means of a simple dynamical model based on linear equatorial wave theory. Model results indicate that seasonal variability between 5 degrees N and 5 degrees S is dominated by wind-forced equatorial Kelvin waves and first meridional mode Rossby waves of the first and second baroclinic modes. The sum of the Rossby waves and Kelvin waves results in westward propagation in the equatorial zonal currents and off-equatorial thermal structure and, yet, eastward propagation in thermocline depth and dynamic height along the equator in the eastern and central Pacific. C1 NOAA, Pacific Marine Environm Lab, Seattle, WA 98115 USA. Univ Washington, Sch Oceanog, Seattle, WA 98195 USA. RP Yu, X (reprint author), NOAA, Pacific Marine Environm Lab, 7600 Sand Point Way NE, Seattle, WA 98115 USA. RI McPhaden, Michael/D-9799-2016 NR 69 TC 94 Z9 96 U1 1 U2 9 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 MAY PY 1999 VL 29 IS 5 BP 925 EP 947 DI 10.1175/1520-0485(1999)029<0925:SVITEP>2.0.CO;2 PG 23 WC Oceanography SC Oceanography GA 200WW UT WOS:000080563900005 ER PT J AU Beers, JS Penzes, WB AF Beers, JS Penzes, WB TI The NIST length scale interferometer SO JOURNAL OF RESEARCH OF THE NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY LA English DT Article DE graduated scales; interferometry; length; measurement assurance; measurement uncertainty ID INDEX; AIR AB The National Institute of Standards and Technology (NIST) interferometer for measuring graduated length scales has been in use since 1965. It was developed in response to the redefinition of the meter in 1960 from the prototype platinum-iridium bar to the wavelength of light. The history of the interferometer is recalled, and its design and operation described. A continuous program of modernization by making physical modifications, measurement procedure changes and computational revisions is described, and the effects of these changes are evaluated. Results of a long-term measurement assurance program, the primary control on the measurement process, are presented, and improvements in measurement uncertainty are documented. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NR 28 TC 20 Z9 21 U1 0 U2 0 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 MAY-JUN PY 1999 VL 104 IS 3 BP 225 EP 252 DI 10.6028/jres.104.017 PG 28 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 223VZ UT WOS:000081863400001 ER PT J AU Navarro, M Bruce, SS Johnson, BC Murthy, AV Saunders, RD AF Navarro, M Bruce, SS Johnson, BC Murthy, AV Saunders, RD TI Vacuum processing technique for development of primary standard blackbodies SO JOURNAL OF RESEARCH OF THE NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY LA English DT Article DE blackbody sources; fixed-point blackbodies; ITS-90; radiance temperature; rf furnace ID TEMPERATURE AB Blackbody sources with nearly unity emittance that are in equilibrium with a pure freezing metal such as gold, silver, or copper are used as primary standard sources in the International Temperature Scale of 1990 (ITS-90). Recently, a facility using radio-frequency induction heating for melting and filling the blackbody crucible with the freeze metal under vacuum conditions was developed at the National Institute of Standards and Technology (NIST). The blackbody development under a vacuum environment eliminated the possibility of contamination of the freeze metal during the process. The induction heating, compared to a resistively heated convection oven, provided faster heating of crucible and resulted in shorter turnaround time of about 7 h to manufacture a blackbody. This paper describes the new facility and its application to the development of fixed-point blackbodies. C1 Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Navarro, M (reprint author), Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. NR 9 TC 4 Z9 4 U1 0 U2 0 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 MAY-JUN PY 1999 VL 104 IS 3 BP 253 EP 259 DI 10.6028/jres.104.018 PG 7 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 223VZ UT WOS:000081863400002 ER PT J AU Weissmuller, J McMichael, RD Michels, A Shull, RD AF Weissmuller, J McMichael, RD Michels, A Shull, RD TI Small-angle neutron scattering by the magnetic microstructure of nanocrystalline ferromagnets near saturation SO JOURNAL OF RESEARCH OF THE NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY LA English DT Article DE exchange constant; magnetic anisotropy; magnetic microstructure; magnetism; micromagnetics; nanocrystalline materials; neutron scattering; small-angle neutron scattering; spin-wave stiffness ID NANOSTRUCTURED FE; SPIN-WAVES; ALLOYS; ANISOTROPY; SIZE; NI AB The paper presents a theoretical analysis of elastic magnetic small-angle neutron scattering (SANS) due to the nonuniform magnetic microstructure in nanocrystalline ferromagnets. The reaction of the magnetization to the magnetocrystalline and magnetoelastic anisotropy fields is derived using the theory of micromagnetics. In the limit where the scattering volume is a single magnetic domain, and the magnetization is nearly aligned with the direction of the magnetic field, closed form solutions are given for the differential scattering cross-section as a function of the scattering vector and of the magnetic field. These expressions involve an anisotropy field scattering function, that depends only on the Fourier components of the anisotropy field microstructure, not on the applied field, and a micromagnetic response function for SANS, that can be computed From tabulated values of the materials parameters saturation magnetization and exchange stiffness constant or spin wave stiffness constant. Based on these results, it is suggested that the anisotropy field scattering function S-H can be extracted from experimental SANS data. A sum rule for S-H suggests measurement of the volumetric mean square anisotropy field. When magnetocrystalline anisotropy is dominant, then a mean grain size or the grain size distribution may be determined by analysis of S-H. C1 Forschungszentrum Karlsruhe, Inst Nanotechnol, D-76021 Karlsruhe, Germany. Univ Saarland, D-66041 Saarbrucken, Germany. Natl Inst Stand & Technol, Gaithersburg, MD 20899 USA. RP Weissmuller, J (reprint author), Forschungszentrum Karlsruhe, Inst Nanotechnol, D-76021 Karlsruhe, Germany. RI Weissmuller, Jorg/C-3967-2009; McMichael, Robert/J-8688-2012; Shull, Robert/F-5971-2013; Michels, Andreas/F-6588-2014; OI Weissmuller, Jorg/0000-0002-8958-4414; McMichael, Robert/0000-0002-1372-664X NR 42 TC 29 Z9 29 U1 0 U2 9 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 MAY-JUN PY 1999 VL 104 IS 3 BP 261 EP 275 DI 10.6028/jres.104.019 PG 15 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 223VZ UT WOS:000081863400003 ER EF