FN Thomson Reuters Web of Science™ VR 1.0 PT J AU Niu, GF Krithivasan, R Cressler, JD Riggs, PA Randall, BA Marshall, PW Reed, RA Gilbert, B AF Niu, GF Krithivasan, R Cressler, JD Riggs, PA Randall, BA Marshall, PW Reed, RA Gilbert, B TI A comparison of SEU tolerance in high-speed SiGe HBT digital logic designed with multiple circuit architectures SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 39th Annual International Nuclear and Space Radiation Effects Conference (NSREC) CY JUL 15-19, 2002 CL PHOENIX, AZ SP IEEE DE charge collection; circuit modeling; current-mode logic; heterojunction bipolar transistor (HBT); SiGe; single event effects AB The single-event upset (SEU) responses of three D flip-flop circuits, including two unhardened, and one current-sharing hardened (CSH) circuit, are examined using device and circuit simulation. The circuit that implements the conventional D flip-flop logic using standard bipolar NAND gates shows much better SEU performance than the other two. Cross coupling at transistor level in the storage cell of the other two circuits increases their vulnerability to SEU. The observed differences are explained by analyzing the differential output of the emitter coupled pair being hit. These results suggest a potential path for achieving sufficient SEU tolerance in high-speed SiGe heterojunction bipolar transistor (HBT) digital logic for many space applications. C1 Auburn Univ, Dept Elect Commun Engn, Auburn, AL 36849 USA. Mayo Fdn, Rochester, MN 55905 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Niu, GF (reprint author), Auburn Univ, Dept Elect Commun Engn, Auburn, AL 36849 USA. EM guofu@eng.auburn.edu RI Krithivasan, Ramkumar/D-3549-2011 NR 10 TC 24 Z9 24 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD DEC PY 2002 VL 49 IS 6 BP 3107 EP 3114 DI 10.1109/TNS.2002.805390 PN 1 PG 8 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA 629NY UT WOS:000180056800074 ER PT J AU Seidleck, C Buchner, S Kim, HS Marshall, PW LaBel, KA AF Seidleck, C Buchner, S Kim, HS Marshall, PW LaBel, KA TI Test methodology for characterizing the SEE response of a commercial IEEE 1394 serial bus (FireWire) SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 39th Annual International Nuclear and Space Radiation Effects Conference (NSREC) CY JUL 15-19, 2002 CL PHOENIX, ARIZONA SP IEEE DE communications; heavy ions; IEEE standards; networks; nuclear radiation effects; proton radiation; radiation effects; registers AB The single-event effect (SEE) response of an IEEE 1394 FireWire serial bus was tested with heavy ions. A unique approach to categorizing the SEEs is presented. C1 Raytheon, Lanham, MD 20706 USA. QSS, Seabrook, MD 20706 USA. Jackson & Tull Chartered Engn, Washington, DC 20018 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Seidleck, C (reprint author), Raytheon, Lanham, MD 20706 USA. NR 1 TC 4 Z9 4 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD DEC PY 2002 VL 49 IS 6 BP 3129 EP 3134 DI 10.1109/TNS.2002.805338 PN 1 PG 6 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA 629NY UT WOS:000180056800077 ER PT J AU Irom, F Farmanesh, FF Johnston, AH Swift, GM Millward, DG AF Irom, F Farmanesh, FF Johnston, AH Swift, GM Millward, DG TI Single-event upset in commercial silicon-on-insulator PowerPC microprocessors SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 39th Annual International Nuclear and Space Radiation Effects Conference (NSREC) CY JUL 15-19, 2002 CL PHOENIX, ARIZONA SP IEEE DE cyclotron; heavy ion beams; heavy ions; interrupts; microprocessors; protons; radiation effects; silicon on insulator; single event upset ID TECHNOLOGIES AB Single-event upset effects from heavy ions and protons are measured for Motorola and IBM silicon-on-insulator (SOI) microprocessors, and, compared with results for similar devices with bulk substrates. The cross sections of the SOI processors are lower than their bulk counterparts, but the threshold is about the same, even though the charge collections depth is more than an order of magnitude smaller in the SOI devices. The upset rates are low enough to allow these devices to be used in space applications where occasional register or functional operating errors can be tolerated. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Millward Res, San Diego, CA 92128 USA. RP Irom, F (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 20 TC 30 Z9 31 U1 0 U2 3 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD DEC PY 2002 VL 49 IS 6 BP 3148 EP 3155 DI 10.1109/TNS.2002.805441 PN 1 PG 8 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA 629NY UT WOS:000180056800080 ER PT J AU Rezgui, S Swift, GM Velazco, R Farmanesh, FF AF Rezgui, S Swift, GM Velazco, R Farmanesh, FF TI Validation of an SEU simulation technique for a complex processor: PowerPC7400 SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 39th Annual International Nuclear and Space Radiation Effects Conference (NSREC) CY JUL 15-19, 2002 CL PHOENIX, ARIZONA SP IEEE DE extraterrestrial radiation effects; fault injection; heavy-ion testing; integrated circuit radiation effects; integrated circuit testing; ion radiation effects; microprocessor testing; PowerPC7400; processor errors; radiation effects; semiconductor device radiation effects; single-event upset ID ARCHITECTURES AB Results from fault injection experiments on a modern complex processor, the PPC7400, are combined with static, register ground testing to predict single-event upset rates of several benchmark application programs. These results compare favorably with in-beam measurements on the same programs. C1 TIMA Lab, Grenoble, France. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Rezgui, S (reprint author), TIMA Lab, Grenoble, France. NR 8 TC 6 Z9 6 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 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD DEC PY 2002 VL 49 IS 6 BP 3156 EP 3162 DI 10.1109/TNS.2002.805982 PN 1 PG 7 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA 629NY UT WOS:000180056800081 ER PT J AU McClure, SS Edmonds, LD Mihailovich, R Johnston, AH Alonzo, P DeNatale, J Lehman, J Yui, C AF McClure, SS Edmonds, LD Mihailovich, R Johnston, AH Alonzo, P DeNatale, J Lehman, J Yui, C TI Radiation effects in micro-electromechanical systems (MEMS): RF relays SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 39th Annual International Nuclear and Space Radiation Effects Conference (NSREC) CY JUL 15-19, 2002 CL PHOENIX, ARIZONA SP IEEE DE micro-electromechanical devices; radiation effects; RF switch ID ACCELEROMETERS AB GaAs micro-electromechanical RF relays fabricated by surface micromachining techniques were characterized for their response to total ionizing dose. Microrelays with two different geometries were studied. For one geometry, changes in switch actuation voltage at moderate dose levels were observed. For an alternative geometry, no change in actuation voltage was observed. A mechanism for dielectric charge trapping and its effect on the electrostatic force is proposed. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Rockwell Int Sci Ctr, Thousand Oaks, CA 91360 USA. RP McClure, SS (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 10 TC 46 Z9 46 U1 3 U2 5 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD DEC PY 2002 VL 49 IS 6 BP 3197 EP 3202 DI 10.1109/TNS.2002.805406 PN 1 PG 6 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA 629NY UT WOS:000180056800087 ER PT J AU Cressler, JD Krithivasan, R Zhang, G Niu, GF Marshall, PW Kim, HS Reed, RA Palmer, MJ Joseph, AJ AF Cressler, JD Krithivasan, R Zhang, G Niu, GF Marshall, PW Kim, HS Reed, RA Palmer, MJ Joseph, AJ TI An investigation of the origins of the variable proton tolerance in multiple SiGe HBT BiCMOS technology generations SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 39th Annual International Nuclear and Space Radiation Effects Conference (NSREC) CY JUL 15-19, 2002 CL PHOENIX, AZ SP IEEE DE BiCMOS; bipolar transistor; HBT; proton radiation; shallow trench isolation; SiGe; silicon-germanium AB This paper presents the first investigation of the physical origins of the, observed variable proton tolerance in multiple SiGe HBT BiCMOS technology generations. We use the combination of an extensive set of newly measured proton data on distinct SiGe HBT BiCMOS technology generations, detailed calibrated 2-D MEDICI simulations for both the SiGe HBT and Si CMOS devices, as well as reverse-bias emitter-base and forward-bias electrical stress data to aid the analysis. We find that the scaling-induced increase in the emitter-base electric field under the spacer oxide in the SiGe HBT is primarily responsible for the degraded radiation tolerance with technology scaling, while the decrease in shallow-trench thickness is largely responsible for the improved nFET radiation tolerance with technology scaling. C1 Georgia Inst Technol, Sch Elect & Comp Engn, Atlanta, GA 30332 USA. Auburn Univ, Alabama Microelect Sci & Technol Ctr, Elect & Comp Engn Dept, Auburn, AL 36849 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Jackson & Tull Chartered Engn, Washington, DC 20018 USA. RP Cressler, JD (reprint author), Georgia Inst Technol, Sch Elect & Comp Engn, Atlanta, GA 30332 USA. EM cressler@ece.gatech.edu RI Krithivasan, Ramkumar/D-3549-2011 NR 11 TC 42 Z9 42 U1 1 U2 3 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD DEC PY 2002 VL 49 IS 6 BP 3203 EP 3207 DI 10.1109/TNS.2002.805362 PN 1 PG 5 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA 629NY UT WOS:000180056800088 ER PT J AU Zhang, SM Cressler, JD Subbanna, S Groves, R Niu, GF Isaacs-Smith, T Williams, JR Bakhru, H Marshall, PW Kim, HS Reed, RA AF Zhang, SM Cressler, JD Subbanna, S Groves, R Niu, GF Isaacs-Smith, T Williams, JR Bakhru, H Marshall, PW Kim, HS Reed, RA TI An investigation of proton energy effects in SiGe HBT technology SO IEEE TRANSACTIONS ON NUCLEAR SCIENCE LA English DT Article; Proceedings Paper CT 39th Annual International Nuclear and Space Radiation Effects Conference (NSREC) CY JUL 15-19, 2002 CL PHOENIX, AZ SP IEEE DE damage factor; HBT; inductors; proton energy effects; proton tolerance; radiation; SiGe; silicon-germanium ID INDUCED DISPLACEMENT DAMAGE; BICMOS TECHNOLOGY; SILICON; DEPENDENCE; RF; IRRADIATION; TRANSISTORS; INDUCTORS; WAFERS AB We present the first investigation of low energy (1.75 MeV) proton irradiation in SiGe HBT's and discuss proton energy effects in SiGe HBT technology. The results show that after 1.75 MeV 1 x 10(14) p/cm(2), a semi-insulating substrate is obtained and the peak quality factor of the monolithic inductors is improved by about 18% at 1.6 GHz. Although large current gain degradation for the SiGe HBT's was observed in the RIF bias region after 1 x 10(14) p/cm(2), the degradation in peak f(T) is only about 11 %. Proton energy studies from 1.75 MeV to 200 MeV in SiGe HBT's suggest that the conventional damage factor can be used to estimate energy-dependent proton-induced radiation damage in this technology. C1 Auburn Univ, Elect & Comp Engn Dept, Alabama Microelect Sci & Technol Ctr, Auburn, AL 36849 USA. IBM Microelect, Hopewell Jct, NY 12533 USA. Auburn Univ, Phys Dept, Auburn, AL 36849 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Georgia Inst Technol, Sch Elect & Comp Engn, Atlanta, GA 30332 USA. SUNY Albany, Dept Phys, Albany, NY 12222 USA. Jackson & Tull Chartered Engineers, Washington, DC 20018 USA. RP Zhang, SM (reprint author), Cypress Semicond Corp, Lexington, KY 40507 USA. NR 23 TC 5 Z9 5 U1 1 U2 3 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 0018-9499 J9 IEEE T NUCL SCI JI IEEE Trans. Nucl. Sci. PD DEC PY 2002 VL 49 IS 6 BP 3208 EP 3212 DI 10.1109/TNS.2002.805361 PN 1 PG 5 WC Engineering, Electrical & Electronic; Nuclear Science & Technology SC Engineering; Nuclear Science & Technology GA 629NY UT WOS:000180056800089 ER PT J AU Seelinger, M Yoder, JD Baumgartner, ET Skaar, SB AF Seelinger, M Yoder, JD Baumgartner, ET Skaar, SB TI High-precision visual control of mobile manipulators SO IEEE TRANSACTIONS ON ROBOTICS AND AUTOMATION LA English DT Article DE machine vision; mobile manipulators; mobile robots; planetary exploration ID CAMERA-SPACE MANIPULATION AB In this paper, we present a high-precision visual control method for mobile manipulators called mobile camera-space manipulation (MCSM). Development of MCSM was inspired by the unique challenges presented in conducting unmanned planetary exploration using rovers. In order to increase the efficacy of such missions, the amount of human interaction must be minimized due to the large time delay and high cost of transmissions between Earth and other planets. Using MCSM, the rover can maneuver itself into position, engage a target rock, and perform any of a variety of manipulation tasks all with one round-trip transmission of instruction. MCSM also. achieves a high level of precision in positioning the onboard manipulator relative to its target. Experimental results are presented in which a rover positions a tool mounted in its manipulator to within I mm of the desired target feature on a rock. MCSM makes efficient use of all of the system's degrees of freedom (DOF), which reduces the required number of actuators for the manipulator. This reduction in manipulator DOFs decreases overall system weight, power consumption, and complexity while increasing reliability. MCSM does not rely on a calibrated camera system. Its excellent positioning precision is robust to model errors and uncertainties in measurements, a great strength for systems operating in harsh environments. C1 YSI, Urbana, IL 61801 USA. Ohio No Univ, Dept Mech Engn, Ada, OH 45810 USA. NASA, Jet Prop Lab, Mech & Robot Technol Grp, Pasadena, CA 91109 USA. Univ Notre Dame, Dept Aerosp & Mech Engn, Notre Dame, IN 46556 USA. RP YSI, Urbana, IL 61801 USA. EM mseelinger@yodersoftware.com; j-yoder@onu.edu; Eric.T.Baumgartner@jpl.nasa.gov; skaar.1@nd.edu RI Seelinger, Michael/B-3914-2013 OI Seelinger, Michael/0000-0002-6916-0593 NR 25 TC 24 Z9 24 U1 0 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 1042-296X J9 IEEE T ROBOTIC AUTOM JI IEEE Trans. Robot. Autom. PD DEC PY 2002 VL 18 IS 6 BP 957 EP 965 DI 10.1109/TRA.2002.805647 PG 9 WC Automation & Control Systems; Engineering, Electrical & Electronic; Robotics SC Automation & Control Systems; Engineering; Robotics GA 632FV UT WOS:000180214000009 ER PT J AU Rivera, G Savitzky, AH Hinkley, JA AF Rivera, G Savitzky, AH Hinkley, JA TI Mechanical properties of the integument of the Common Garter Snake, Thamnophis sirtalis (Serpentes : Colubridae). SO INTEGRATIVE AND COMPARATIVE BIOLOGY LA English DT Meeting Abstract CT Annual Meeting of the Society-for-Integrative-and-Comparative-Biology CY JAN 02-07, 2002 CL ANAHEIM, CALIFORNIA SP Soc Integrat & Comparat Biol C1 Old Dominion Univ, Norfolk, VA 23529 USA. NASA, Langley Res Ctr, Hampton, VA 23665 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SOC INTEGRATIVE COMPARATIVE BIOLOGY PI MCLEAN PA 1313 DOLLEY MADISON BLVD, NO 402, MCLEAN, VA 22101 USA SN 1540-7063 J9 INTEGR COMP BIOL JI Integr. Comp. Biol. PD DEC PY 2002 VL 42 IS 6 BP 1301 EP 1301 PG 1 WC Zoology SC Zoology GA 669ND UT WOS:000182356600597 ER PT J AU Mavriplis, DJ AF Mavriplis, DJ TI Parallel performance investigations of an unstructured mesh Navier-Stokes solver SO INTERNATIONAL JOURNAL OF HIGH PERFORMANCE COMPUTING APPLICATIONS LA English DT Article ID AGGLOMERATION; EQUATIONS AB The implementation and performance of a hybrid OpenMP/MPI parallel communication strategy for an unstructured mesh computational fluid dynamics code is described. The solver is cache efficient and fully vectorizable, and is parallelized using a two-level hybrid MPI-OpenMP implementation suitable for shared and/or distributed memory architectures, as well as clusters of shared memory machines. Parallelism is obtained through domain decomposition for both communication models. Single processor computational rates as well as scalability curves are given on various architectures. For the architectures studied in this work, the OpenMP or hybrid OpenMP/MPI communication strategies achieved no appreciable performance benefit over an exclusive MPI communication strategy. C1 NASA, Inst Comp Applicat Sci & Engn, Langley Res Ctr, Hampton, VA 23681 USA. RP Mavriplis, DJ (reprint author), NASA, Inst Comp Applicat Sci & Engn, Langley Res Ctr, Mail Stop 132C, Hampton, VA 23681 USA. NR 20 TC 7 Z9 7 U1 0 U2 0 PU SAGE PUBLICATIONS LTD PI LONDON PA 6 BONHILL STREET, LONDON EC2A 4PU, ENGLAND SN 1094-3420 J9 INT J HIGH PERFORM C JI Int. J. High Perform. Comput. Appl. PD WIN PY 2002 VL 16 IS 4 BP 395 EP 407 PG 13 WC Computer Science, Hardware & Architecture; Computer Science, Interdisciplinary Applications; Computer Science, Theory & Methods SC Computer Science GA 628NH UT WOS:000180002000003 ER PT J AU Anderson, JD Turyshev, SG Nieto, MM AF Anderson, JD Turyshev, SG Nieto, MM TI A mission to test the pioneer anomaly SO INTERNATIONAL JOURNAL OF MODERN PHYSICS D LA English DT Article AB Analysis of the radio tracking data from the Pioneer 10/11 spacecraft has consistently indicated the presence of an anomalous small Doppler frequency drift. The drift can be interpreted as being due to a constant acceleration of a(P) = (8.74 +/- 1.33) x 10(-8) cm/s(2) directed towards the Sun. Although it is suspected that there is a systematic origin to the effect, none has been found. The nature of this anomaly has become of growing interest in the fields of relativistic cosmology, astro- and gravitational physics as well as in the areas of spacecraft design and high-precision navigation. We present a concept for a designated deep-space mission to test the discovered anomaly. A number of critical requirements and design considerations for such a mission are outlined and addressed. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Los Alamos Natl Lab, Theoret Div MSB285, Los Alamos, NM 87545 USA. RP Anderson, JD (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 9 TC 21 Z9 21 U1 0 U2 1 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA JOURNAL DEPT PO BOX 128 FARRER ROAD, SINGAPORE 912805, SINGAPORE SN 0218-2718 J9 INT J MOD PHYS D JI Int. J. Mod. Phys. D PD DEC PY 2002 VL 11 IS 10 BP 1545 EP 1551 DI 10.1142/S0218271802002876 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 638RT UT WOS:000180584600007 ER PT J AU Mohler, SR AF Mohler, SR TI The origins and technology of the advanced extravehicular space suit. SO ISIS LA English DT Book Review C1 Wright State Univ, Sch Med, Dept Community Hlth, Dayton, OH 45435 USA. NASA, Aerosp Med Residency Training Program, Washington, DC 20546 USA. RP Mohler, SR (reprint author), Wright State Univ, Sch Med, Dept Community Hlth, Dayton, OH 45435 USA. NR 1 TC 0 Z9 0 U1 1 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0021-1753 J9 ISIS JI Isis PD DEC PY 2002 VL 93 IS 4 BP 764 EP 764 DI 10.1086/376073 PG 1 WC History & Philosophy Of Science SC History & Philosophy of Science GA 657UR UT WOS:000181685200123 ER PT J AU Aguirre, AA Balazs, GH Spraker, TR Murakawa, SKK Zimmerman, B AF Aguirre, AA Balazs, GH Spraker, TR Murakawa, SKK Zimmerman, B TI Pathology of oropharyngeal fibropapillomatosis in green turtles Chelonia mydas SO JOURNAL OF AQUATIC ANIMAL HEALTH LA English DT Article AB Complete gross and histopathologic examinations of the oral cavity, tongue, pharynx, larynx, and glottis were performed in five Hawaiian green turtles Chelonia mydas with fibropapillomatosis. These examinations demonstrated that the oropharyngeal fibropapillomas were similar to characteristic external fibropapillomas previously described for green turtles. The size, appearance, and anatomic site of the tumors confirmed that these turtles presented total or partial occlusion of the nasopharynx, glottis, larynx, and adjacent tissues. The fibropapillomas of the oropharynx were considered locally invasive and severely modified the morphophysiology of respiration and feeding in these turtles. To the best of our knowledge, this is the first report of oropharyngeal fibropapillomatosis in sea turtles. C1 Columbia Univ, Wildlife Trust, Palisades, NY 10964 USA. NOAA, Natl Marine Fisheries Serv, Honolulu, HI 96822 USA. Colorado State Univ, State Vet Diagnost Lab, Ft Collins, CO 80523 USA. Wildlife Hlth Int, Ft Collins, CO 80522 USA. RP Aguirre, AA (reprint author), Columbia Univ, Wildlife Trust, 61 Route 9 W, Palisades, NY 10964 USA. NR 20 TC 12 Z9 13 U1 0 U2 14 PU AMER FISHERIES SOC PI BETHESDA PA 5410 GROSVENOR LANE SUITE 110, BETHESDA, MD 20814-2199 USA SN 0899-7659 J9 J AQUAT ANIM HEALTH JI J. Aquat. Anim. Health PD DEC PY 2002 VL 14 IS 4 BP 298 EP 304 DI 10.1577/1548-8667(2002)014<0298:POOFIG>2.0.CO;2 PG 7 WC Fisheries; Veterinary Sciences SC Fisheries; Veterinary Sciences GA 636FH UT WOS:000180443600009 ER PT J AU Kursinski, ER Syndergaard, S Flittner, D Feng, D Hajj, G Herman, B Ward, D Yunck, T AF Kursinski, ER Syndergaard, S Flittner, D Feng, D Hajj, G Herman, B Ward, D Yunck, T TI A microwave occultation observing system optimized to characterize atmospheric water, temperature, and geopotential via absorption SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article ID GLOBAL POSITIONING SYSTEM; RADIO OCCULTATION; EARTHS ATMOSPHERE; GPS OCCULTATIONS; VAPOR; VENUS AB A new remote sensing concept extrapolated from the GPS occultation concept is presented in which the signal frequencies are chosen to determine atmospheric water, temperature, and the geopotential of atmospheric pressure surfaces. Using frequencies near the 22- and 183-GHz water lines allows not only the speed of light to be derived as a GPS occultation but also derivation of profiles of absorption caused by atmospheric water. Given the additional water information, moisture and temperature as well as the geopotential of pressure surfaces can be separated and solved for. Error covariance results indicate that the accuracies of individual water profiles will be 0.5%-3% extending from roughly 1-75-km altitude. Temperature accuracies of individual profiles will be sub-Kelvin from similar to1- to 70-km altitude depending on latitude and season. Accuracies of geopotential heights of pressure will be 10-20 m from the surface to 60-km altitude. These errors are random such that climatological averages derived from this data will be significantly more accurate. Owing to the limb-viewing geometry, the along-track resolution is comparable to the 200-300 km of the GPS occultation observations, but the shorter 22- and 183-GHz wavelengths improve the diffraction-limited vertical resolution to 100-300 m. The technique can be also used to determine profiles of other atmospheric constituents such as upper-tropospheric and stratospheric ozone by using frequencies near strong lines of that constituent. The combined dynamic range, accuracy, vertical resolution, and ability to penetrate clouds far surpass that of any present or planned satellite sensors. A constellation of such sensors would provide an all-weather, global remote sensing capability including full sampling of the diurnal cycle for process studies related to water, climate research, and weather prediction in general. C1 Univ Arizona, Dept Atmospher Sci, Tucson, AZ 85721 USA. CALTECH, Jet Propuls Lab, Pasadena, CA 91125 USA. RP Kursinski, ER (reprint author), Univ Arizona, Dept Atmospher Sci, POB 210081, Tucson, AZ 85721 USA. RI Syndergaard, Stig/C-1103-2017 OI Syndergaard, Stig/0000-0003-3119-2618 NR 25 TC 35 Z9 35 U1 1 U2 4 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 DEC PY 2002 VL 19 IS 12 BP 1897 EP 1914 DI 10.1175/1520-0426(2002)019<1897:AMOOSO>2.0.CO;2 PG 18 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA 619GR UT WOS:000179468100001 ER PT J AU Gourrion, J Vandemark, D Bailey, S Chapron, B Gommenginger, GP Challenor, PG Srokosz, MA AF Gourrion, J Vandemark, D Bailey, S Chapron, B Gommenginger, GP Challenor, PG Srokosz, MA TI A two-parameter wind speed algorithm for Ku-band altimeters SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article ID SIGNIFICANT WAVE HEIGHT; RADAR CROSS-SECTION; SURFACE WIND; OCEAN BACKSCATTER; MODEL FUNCTIONS; GEOSAT; BUOYS AB Globally distributed crossovers of altimeter and scatterometer observations clearly demonstrate that ocean altimeter backscatter correlates with both the near-surface wind speed and the sea state. Satellite data from TOPEX/Poseidon and NSCAT are used to develop an empirical altimeter wind speed model that attenuates the sea-state signature and improves upon the present operational altimeter wind model. The inversion is defined using a multilayer perceptron neural network with altimeter-derived backscatter and significant wave height as inputs. Comparisons between this new model and past single input routines indicates that the rms wind error is reduced by 10%-15% in tandem with the lowering of wind error residuals dependent on the sea state. Both model intercomparison and validation of the new routine are detailed, including the use of large independent data compilations that include the SeaWinds and ERS scatterometers, ECMWF wind fields, and buoy measurements. The model provides consistent improvement against these varied sources with a wind-independent bias below 0.3 m s(-1). The continuous form of the defined function, along with the global data used in its derivation, suggest an algorithm suitable for operational application to Ku-band altimeters. Further model improvement through wave height inclusion is limited due to an inherent multivaluedness between any single realization of the altimeter measurement pair [sigma(o), H-s] and observed near-surface winds. This ambiguity indicates that H-s is a limited proxy for variable gravity wave properties that impact upon altimeter backscatter. C1 NASA, Goddard Space Flight Ctr, Wallops Isl, VA 23337 USA. IFREMER, Dept Oceanog Spatiale, Plouzane, France. Southampton Oceanog Ctr, James Rennell Div, Southampton, Hants, England. RP Vandemark, D (reprint author), NASA, Goddard Space Flight Ctr, Bldg N-159,Room E222, Wallops Isl, VA 23337 USA. RI Chapron, Bertrand/O-6527-2015; Challenor, Peter/M-2579-2016 OI Challenor, Peter/0000-0001-8661-2718 NR 35 TC 75 Z9 77 U1 0 U2 5 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 DEC PY 2002 VL 19 IS 12 BP 2030 EP 2048 DI 10.1175/1520-0426(2002)019<2030:ATPWSA>2.0.CO;2 PG 19 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA 619GR UT WOS:000179468100011 ER PT J AU Welton, EJ Campbell, JR AF Welton, EJ Campbell, JR TI Micropulse lidar signals: Uncertainty analysis SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article ID ARM AB Elastic backscatter lidars are used to determine the vertical distribution of cloud and aerosol layers. One such lidar is the micropulse lidar (MPL). A recent paper by Campbell et al. described an algorithm used to process MPL signals. The paper presented procedures that correct for various instrument effects present in the raw signals. The primary instrument effects include afterpulse (detector noise induced from the firing of the laser) and overlap (poor near-range data collection). The outgoing energy of the laser pulses and the statistical uncertainty of the MPL detector must also be correctly determined in order to assess the accuracy of MPL observations. The uncertainties associated with each of these instrument effects, and their contribution to the net uncertainty in corrected MPL signals, were not discussed in the earlier paper. Here in the uncertainties associated with each instrument parameter in the MPL signal are discussed. The uncertainties are propagated through the entire correction process to give a net uncertainty on the final corrected MPL signal. The results show that in the near range, the overlap uncertainty dominates. At altitudes above the overlap region, the dominant source of uncertainty is caused by uncertainty in the pulse energy. However, if the laser energy is low, then during midday, high solar background levels can significantly reduce the signal-to-noise ratio of the detector. In such a case, the statistical uncertainty of the detector count rate becomes dominant at altitudes above the overlap region. C1 Univ Maryland, Goddard Earth Sci & Technol Ctr, Baltimore, MD 21250 USA. Sci Syst & Applicat Inc, Lanham, MD USA. RP Welton, EJ (reprint author), Univ Maryland, Goddard Earth Sci & Technol Ctr, Baltimore Cty, Baltimore, MD 21250 USA. RI Welton, Ellsworth/A-8362-2012; Campbell, James/C-4884-2012 OI Campbell, James/0000-0003-0251-4550 NR 10 TC 63 Z9 63 U1 1 U2 10 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 DEC PY 2002 VL 19 IS 12 BP 2089 EP 2094 DI 10.1175/1520-0426(2002)019<2089:MLSUA>2.0.CO;2 PG 6 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA 619GR UT WOS:000179468100015 ER PT J AU Tran, N Hancock, DW Hayne, GS Lockwood, DW Vandemark, D Driscoll, ML Sailor, RV AF Tran, N Hancock, DW Hayne, GS Lockwood, DW Vandemark, D Driscoll, ML Sailor, RV TI Assessment of the cycle-to-cycle noise level of the Geosat Follow-On, TOPEX, and Poseidon altimeters SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article ID RADAR ALTIMETER; TOPEX/POSEIDON; ACCURACY AB The Geodetic Satellite (Geosat) Follow-On (GFO), Ocean Topography Experiment (TOPEX), and Poseidon altimeter white-noise levels have been evaluated using a technique based on high-pass filtering of 1-Hz sea surface height time series. High-pass filtering removes the geoid and oceanography signals while revealing the random noise. This filtering technique is simpler to use than the repeat-track method, gives essentially the same results, and makes it easier to analyze much larger amounts of data to investigate subtle variations in noise levels. The new noise-level measurements provided here all show stable noise-process characteristics from cycle to cycle, with a linear dependence of the noise level upon significant wave height (SWH). The GFO altimeter noise level is estimated to be 2.5 cm for an SWH of 2 m. The Poseidon noise level is estimated at 2.0 cm for the same value of 2 m SWH. The TOPEX altimeter noise level is 1.8 cm when the dual-frequency ionospheric correction is included; when this noisy correction is not used, the level is reduced to 1.5 cm. Although the dual-frequency ionospheric correction provides an average improvement over the "Doppler orbitography and radiopositioning integrated by satellite'' (DORIS) correction, high-frequency noise enters into the dual-frequency correction via noise from the Ku- and C-band ranges. Because the variations in ionospheric refraction are a relatively long wavelength global effect (with strong dependence on latitude), the dual-frequency ionospheric correction should be low-pass filtered before use, and this correction should not be included when estimating the high-frequency noise level of the altimeter. C1 Raytheon ITSS, Wallops Isl, VA USA. NASA, Goddard Space Flight Ctr, Wallops Flight Facil, Wallops Isl, VA 23337 USA. TASC Inc, Reading, MA USA. RP Tran, N (reprint author), CLS, Space Oceanog Div, 8-10 Rue Hermes, F-31526 Ramonville St Agne, France. NR 19 TC 5 Z9 5 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0739-0572 J9 J ATMOS OCEAN TECH JI J. Atmos. Ocean. Technol. PD DEC PY 2002 VL 19 IS 12 BP 2095 EP 2107 DI 10.1175/1520-0426(2002)019<2095:AOTCTC>2.0.CO;2 PG 13 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA 619GR UT WOS:000179468100016 ER PT J AU Wang, DY AF Wang, DY TI A time-dependent quantum dynamics study of the H-2+CH3 -> H+CH4 reaction SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID H-2 REVERSIBLE CH4+H; H+CH4->H-2+CH3 REACTION; RATE CONSTANTS; DIMENSIONALITY CALCULATIONS; REDUCED DIMENSIONALITY; SHOCK-TUBE; SCATTERING; CH4+H->CH3+H-2; H+CH4->CH3+H-2; KINETICS AB We present a time-dependent wave-packet propagation calculation for the H-2+CH3-->H+CH4 reaction in six degrees of freedom and for zero total angular momentum. Initial state selected reaction probabilities for different initial rotational-vibrational states are presented in this study. Excitation of the H-2 stretch enhances the reaction probability, whereas the excitation of the CH3 umbrella mode has the opposite effect. The cumulative reaction probability (CRP) is obtained by summing over initial-state-selected reaction probabilities. The energy-shift approximation to account for the contribution of degrees of freedom missing in the six-dimensional calculation is employed to obtain an approximate full-dimensional CRP. Thermal rate constant is compared with different experiment results. C1 NASA, Ames Res Ctr, Eloret, Moffett Field, CA 94035 USA. RP Wang, DY (reprint author), NASA, Ames Res Ctr, Eloret, Mail Stop T27B-1, Moffett Field, CA 94035 USA. NR 35 TC 30 Z9 30 U1 0 U2 8 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD DEC 1 PY 2002 VL 117 IS 21 BP 9806 EP 9810 DI 10.1063/1.1518027 PG 5 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 614TA UT WOS:000179205700036 ER PT J AU Hashizume, H Xie, SP Fujiwara, M Shiotani, M Watanabe, T Tanimoto, Y Liu, WT Takeuchi, K AF Hashizume, H Xie, SP Fujiwara, M Shiotani, M Watanabe, T Tanimoto, Y Liu, WT Takeuchi, K TI Direct observations of atmospheric boundary layer response to SST variations associated with tropical instability waves over the eastern equatorial Pacific SO JOURNAL OF CLIMATE LA English DT Article ID SEA-SURFACE TEMPERATURE; MOMENTUM BALANCE; WIND; OCEAN; VARIABILITY; GRADIENTS; FRONT; CONVERGENCE; CLOUDINESS; CONVECTION AB Tropical instability waves (TIWs), with a typical wavelength of 1000 km and period of 30 days, cause the equatorial front to meander and result in SST variations on the order of 1degrees-2degreesC. Vertical soundings of temperature, humidity, and wind velocity were obtained on board a Japanese research vessel, which sailed through three fully developed SST waves from 140degrees to 110degreesW along 2degreesN during 21-28 September 1999. A strong temperature inversion is observed throughout the cruise along 2degreesN, capping the planetary boundary layer (PBL) that is 1-1.5 km deep. Temperature response to TIW-induced SST changes penetrates the whole depth of the PBL. In response to an SST increase, air temperature rises in the lowest kilometer and shows a strong cooling at the mean inversion height. As a result, this temperature dipole is associated with little TIW signal in the observed sea level pressure (SLP). The cruise mean vertical profiles show a speed maximum at 400-500 m for both zonal and meridional velocities. SST-based composite profiles of zonal wind velocity show weakened ( intensified) vertical shear within the PBL that is consistent with enhanced ( reduced) vertical mixing, causing surface wind to accelerate ( decelerate) over warm (cold) SSTs. Taken together, the temperature and wind soundings indicate the dominance of the vertical mixing over the SLP-driving mechanism. Based on the authors' measurements, a physical interpretation of the widely used PBL model proposed by Lindzen and Nigam is presented. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Hawaii, Int Pacific Res Ctr, Honolulu, HI 96822 USA. Univ Hawaii, Dept Meteorol, Honolulu, HI 96822 USA. Kyoto Univ, Radio Sci Ctr Space & Atmosphere, Kyoto, Japan. Tohuko Natl Fisheries Res Inst, Shiogama, Japan. Hokkaido Univ, Grad Sch Environm Earth Sci, Sapporo, Hokkaido 060, Japan. Frontier Observat Res Syst Global Change, Yokosuka, Kanagawa, Japan. RP Hashizume, H (reprint author), CALTECH, Jet Prop Lab, Mail Code 300-323,4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM zume@pacific.jpl.nasa.gov RI Xie, Shang-Ping/C-1254-2009; Fujiwara, Masatomo/F-7852-2012; Tanimoto, Youichi/F-8819-2012 OI Xie, Shang-Ping/0000-0002-3676-1325; NR 48 TC 82 Z9 91 U1 1 U2 15 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 DEC PY 2002 VL 15 IS 23 BP 3379 EP 3393 DI 10.1175/1520-0442(2002)015<3379:DOOABL>2.0.CO;2 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 615WH UT WOS:000179269900004 ER PT J AU Druyan, LM Fulakeza, M Lonergan, P AF Druyan, LM Fulakeza, M Lonergan, P TI Dynamic downscaling of seasonal climate predictions over Brazil SO JOURNAL OF CLIMATE LA English DT Article ID OUTGOING LONGWAVE RADIATION; GENERAL-CIRCULATION MODEL; NORTHEAST BRAZIL; GLOBAL PRECIPITATION; SURFACE-TEMPERATURE; REGIONAL MODEL; AMAZON BASIN; PARAMETERIZATION; VARIABILITY; RAINFALL AB Climate projections for March-April-May (MAM) 1985 and 1997 made with the NASA Goddard Institute for Space Studies (GISS) GCM over South America on a 48 latitude by 58 longitude grid are "downscaled'' to 0.5degrees grid spacing. This is accomplished by interpolating the GCM simulation product in time and space to create lateral boundary conditions (LBCs) for synchronous nested simulations by the regional climate model (RCM) of the GISS/Columbia University Center for Climate Systems Research. Both the GCM and the RCM simulations use sea surface temperature (SST) predictions based on persisted February SST anomalies. Each downscaled prediction is evaluated from an ensemble of five simulations and each is compared to a control ensemble of five RCM simulations driven by synchronous NCEP reanalysis data. An additional five-run control ensemble for MAM 1997 tests the impact of "perfect'' SST predictions on the RCM forecast. Results are compared to observational evidence that includes NCEP reanalysis data, Climate Prediction Center (CPC) Merged Analysis of Precipitation ( CMAP) gridded fields, some rain gauge observations, and satellite measurements of monthly mean outgoing longwave radiation. The downscaled predictions and the downscaled analyses both capture the meridional displacement of the intertropical convergence (ITC) precipitation maximum over northern Brazil between the two seasons. The simulation of this feature for MAM 1997 is improved by using actual SST, but the correction of underestimates of eastern Brazil precipitation requires analyzed LBC in place of GCM forcing. The realism of spatial patterns and area averages of precipitation neither improves nor deteriorates with elapsed time, but the variability between individual runs forced by the same LBC decreases with time. The RCM shows a positive bias in surface temperature over central and southeastern Brazil and a positive bias in temperature at 850 mb over the Tropics. Results imply that improvements in seasonal climate prediction at the 0.5degrees spatial scale over Brazil could be realized by more realistic GCM forcing, accurate SST predictions, and improvements in the RCM. C1 NASA, Goddard Inst Space Studies, Ctr Climate Syst Res, New York, NY 10025 USA. Columbia Univ, Earth Inst, Ctr Climate Syst Res, New York, NY USA. Stinger Ghaffarian Technol Inc, NASA, Goddard Inst Space Studies, New York, NY USA. RP Druyan, LM (reprint author), NASA, Goddard Inst Space Studies, Ctr Climate Syst Res, 2880 Broadway, New York, NY 10025 USA. NR 33 TC 20 Z9 26 U1 0 U2 7 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8755 J9 J CLIMATE JI J. Clim. PD DEC PY 2002 VL 15 IS 23 BP 3411 EP 3426 DI 10.1175/1520-0442(2002)015<3411:DDOSCP>2.0.CO;2 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 615WH UT WOS:000179269900006 ER PT J AU Chambers, LH Lin, B Young, DF AF Chambers, LH Lin, B Young, DF TI Examination of new CERES data for evidence of tropical Iris feedback SO JOURNAL OF CLIMATE LA English DT Article ID WATER CLOUD PROPERTIES; ENERGY SYSTEM CERES; VISIBLE MEASUREMENTS; SATELLITE MICROWAVE; EARTH; RADIATION; MISSION AB New data products from the Clouds and the Earth's Radiant Energy System (CERES) instrument on the Tropical Rainfall Measuring Mission Satellite have been examined in the context of the recently proposed adaptive tropical infrared Iris hypothesis. The CERES Single Scanner Footprint data products combine radiative fluxes with cloud properties obtained from a co-orbiting imaging instrument. This enables the use of cloud property based definitions of the various regions in the simple Iris climate model. Regardless of definition, the radiative properties are found to be different from those assigned in the original Iris hypothesis. As a result, the strength of the feedback effect is reduced by a factor of 10 or more. Contrary to the initial Iris hypothesis, most of the definitions tested in this paper result in a small positive feedback. Thus, the existence of an effective infrared iris to counter greenhouse warming is not supported by the CERES data. C1 NASA, Radiat & Aerosols Branch, Langley Res Ctr, Hampton, VA 23681 USA. RP Chambers, LH (reprint author), NASA, Radiat & Aerosols Branch, Langley Res Ctr, MS 420, Hampton, VA 23681 USA. NR 19 TC 19 Z9 19 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8755 J9 J CLIMATE JI J. Clim. PD DEC PY 2002 VL 15 IS 24 BP 3719 EP 3726 DI 10.1175/1520-0442(2002)015<3719:EONCDF>2.0.CO;2 PG 8 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 625JY UT WOS:000179814400014 ER PT J AU Brock, JC Wright, CW Sallenger, AH Krabill, WB Swift, RN AF Brock, JC Wright, CW Sallenger, AH Krabill, WB Swift, RN TI Basis and methods of NASA airborne topographic mapper lidar surveys for coastal studies SO JOURNAL OF COASTAL RESEARCH LA English DT Article DE shoreline change; airborne laser altimetry; LaserMap ID LASER ALTIMETER; TERRAIN MODELS AB This paper provides an overview of the basic principles of airborne laser altimetry for surveys of coastal topography, and describes the methods used in the acquisition and processing of NASA Airborne Topographic Mapper (ATM) surveys that cover much of the conterminous US coastline. This form of remote sensing, also known as "topographic lidar", has undergone extremely rapid development during the last two decades, and has the potential to contribute within a wide range of coastal scientific investigations. Various airborne laser surveying (ALS) applications that are relevant to coastal studies are being pursued by researchers in a range of Earth science disciplines. Examples include the mapping of "bald earth" land surfaces below even moderately dense vegetation in studies of geologic framework and hydrology, and determination of the vegetation canopy structure, a key variable in mapping wildlife habitats. ALS has also proven to be an excellent method for the regional mapping of geomorphic change along barrier island beaches and other sandy coasts due to storms or long-term sedimentary processes. Coastal scientists are adopting ALS as a basic method in the study of an array of additional coastal topics. ALS can provide useful information in the analysis of shoreline change, the prediction and assessment of landslides along seacliffs and headlands, examination of subsidence causing coastal land loss, and in predicting storm surge and tsunami inundation. C1 USGS, Ctr Coastal & Reg Marine Studies, St Petersburg, FL 33701 USA. NASA, Goddard Space Flight Ctr, Wallops Flight Facil, Wallops Isl, VA 23337 USA. NASA, Goddard Space Flight Ctr, EG&G, Wallops Isl, VA 23337 USA. RP Brock, JC (reprint author), USGS, Ctr Coastal & Reg Marine Studies, 600 4th St S, St Petersburg, FL 33701 USA. NR 36 TC 66 Z9 67 U1 3 U2 19 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 WIN PY 2002 VL 18 IS 1 BP 1 EP 13 PG 13 WC Environmental Sciences; Geography, Physical; Geosciences, Multidisciplinary SC Environmental Sciences & Ecology; Physical Geography; Geology GA 524HJ UT WOS:000174006900001 ER PT J AU Banger, KK Duraj, SA Fanwick, PE Hehemann, DG Hepp, AF Martuch, RA AF Banger, KK Duraj, SA Fanwick, PE Hehemann, DG Hepp, AF Martuch, RA TI Synthesis and structural characterization of a novel indium mercapto derivative [ClIn(SCH2(CO)O)(2)](2-) [(4-mepyH)(2)](2+) SO JOURNAL OF COORDINATION CHEMISTRY LA English DT Article DE indium; MOCVD; photovoltaics; coordination; thioglycolic acid; mercapto-acetic acid ID CHEMICAL-VAPOR-DEPOSITION; THIN-FILMS; COMPLEXES; SULFIDE AB The synthesis and structural characterization of a novel In(III) complex is described. The reaction between InCl3 with sodium mercapto-acetic acid (NaSCH2(CO)OH) in 4-methylpyridine (CH3(C5H5N), (4-Mepy)) at 25degreesC affords [ClIn(SCH2(CO)O)(2)](2-) [(4-MepyH)(2)](2+), (1). X-ray diffraction studies of (1) show it to have a distorted square-pyramidal geometry with the [(-SCH2(CO)CO-)] ligands in a trans conformation. The compound crystallizes in the P1 (No. 2) space group with a = 7.8624(6) Angstrom, b = 9.950(1) Angstrom, c = 13.793(2) alpha = 107.60(1)degrees, beta = 90.336(8)degrees, gamma = 98.983(9)degrees, V= 1014.3(4) Angstrom(3), R(Fdegrees) = 0.037 and R-w = 0.048. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. Cleveland State Univ, Dept Chem, Cleveland, OH 44115 USA. Purdue Univ, Dept Chem, W Lafayette, IN 47907 USA. Ohio Aerosp Inst, Cleveland, OH 44142 USA. RP Hepp, AF (reprint author), NASA, Glenn Res Ctr, MS 302-1,21000 Brookpk Rd, Cleveland, OH 44135 USA. NR 17 TC 1 Z9 1 U1 0 U2 0 PU TAYLOR & FRANCIS LTD PI ABINGDON PA 4 PARK SQUARE, MILTON PARK, ABINGDON OX14 4RN, OXON, ENGLAND SN 0095-8972 J9 J COORD CHEM JI J. Coord. Chem. PD DEC PY 2002 VL 55 IS 12 BP 1427 EP 1431 DI 10.1080/0095897021000058817 PG 5 WC Chemistry, Inorganic & Nuclear SC Chemistry GA 645EZ UT WOS:000180964400009 ER PT J AU Brooks, KR AF Brooks, KR TI Monocular motion adaptation affects the perceived trajectory of stereomotion SO JOURNAL OF EXPERIMENTAL PSYCHOLOGY-HUMAN PERCEPTION AND PERFORMANCE LA English DT Article ID IN-DEPTH; SPEED DISCRIMINATION; DIRECTION; PERCEPTION; EYE; DOMINANCE; DISPARITY; CORTEX; IMAGE AB Perceived stereomotion trajectory was measured before and after adaptation to lateral motion in the dominant or nondominant eye to assess the relative contributions of 2 cues: changing disparity and interocular velocity difference. Perceived speed for monocular lateral motion and perceived binocular visual direction (BVD) was also assessed. Unlike stereornotion trajectory perception, the BVD of static targets showed an ocular dominance bias, even without adaptation. Adaptation caused equivalent biases in perceived trajectory and monocular motion speed, without significantly affecting perceived BVD. Predictions from monocular motion data closely match trajectory perception data, unlike those from BVD sources. The results suggest that the interocular velocity differences make a significant contribution to stereomotion trajectory perception. C1 Univ Sussex, Dept Expt Psychol, Brighton, E Sussex, England. RP Brooks, KR (reprint author), NASA, Ames Res Ctr, Human Informat Proc Res Branch, Human Factors Res & Technol Div, M-S 262-2, Moffett Field, CA 94035 USA. EM kbrooks@mail.arc.nasa.gov OI Brooks, Kevin/0000-0003-1424-4092 NR 34 TC 24 Z9 24 U1 0 U2 0 PU AMER PSYCHOLOGICAL ASSOC PI WASHINGTON PA 750 FIRST ST NE, WASHINGTON, DC 20002-4242 USA SN 0096-1523 J9 J EXP PSYCHOL HUMAN JI J. Exp. Psychol.-Hum. Percept. Perform. PD DEC PY 2002 VL 28 IS 6 BP 1470 EP 1482 DI 10.1037//0096-1523.28.6.1470 PG 13 WC Psychology; Psychology, Experimental SC Psychology GA 631YQ UT WOS:000180196200012 PM 12542138 ER PT J AU Guillevic, P Koster, RD Suarez, MJ Bounoua, L Collatz, GJ Los, SO Mahanama, SPP AF Guillevic, P Koster, RD Suarez, MJ Bounoua, L Collatz, GJ Los, SO Mahanama, SPP TI Influence of the interannual variability of vegetation on the surface energy balance - A global sensitivity study SO JOURNAL OF HYDROMETEOROLOGY LA English DT Article ID LEAF-AREA INDEX; GENERAL-CIRCULATION MODELS; LAND-SURFACE; AMAZONIAN DEFORESTATION; PARAMETERIZATION SIB2; STOMATAL-RESISTANCE; CLIMATE SIMULATIONS; GCM SIMULATION; AVHRR DATA; PRECIPITATION AB The degree to which the interannual variability of vegetation phenology affects hydrological fluxes over land is investigated through a series of simulations with the Mosaic land surface model, run both offline and coupled to the NASA Seasonal-to-Interannual Prediction Project (NSIPP) atmospheric general circulation model (GCM). Over a 9-yr period, from 1982 to 1990, interannual variations of global biophysical land surface parameters (i.e., vegetation density and greenness fraction) are derived from Normalized Difference Vegetation Index (NDVI) data collected by the Advanced Very High Resolution Radiometers (AVHRRs). First the sensitivity of evapotranspiration to interannual variations in vegetation properties is evaluated through offline simulations that ignore feedbacks between the land surface and the atmospheric models, and interannual precipitation variations. Evapotranspiration is shown to be highly sensitive to variations in vegetation over wet continental surfaces that are not densely vegetated. The sensitivity is reduced by a saturation effect over dense vegetation covers and physiological control due to environmental stress over arid and semiarid regions. Correlations between evapotranspiration and vegetation anomalies are reduced markedly in offline runs that impose interannual variations in both vegetation and precipitation. They are also strongly reduced in the coupled simulations. Although interannual variations in vegetation properties still influence transpiration and interception loss at the global scale in these runs, their impact on large-scale regional climate is much weaker, apparently because the impact is drowned out by atmospheric variability. C1 CNRS, Ctr Etud Environm Terr & Planetaires, Velizy Villacoublay, France. NASA, Goddard Space Flight Ctr, Hydrol Sci Branch, Lab Hydrospher Sci, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Atmospheres Lab, Climate & Radiat Branch, Greenbelt, MD 20771 USA. Univ Maryland, Dept Meteorol, College Pk, MD 20742 USA. NASA, Goddard Space Flight Ctr, Biospher Sci Branch, Greenbelt, MD 20771 USA. Univ Coll Swansea, Dept Geog, Swansea, W Glam, Wales. UMBC, Goddard Earth Sci & Technol Ctr, Baltimore, MD USA. RP Guillevic, P (reprint author), LCPC, Div Eau, Route Bouaye,BP 4129, F-44341 Bouguenais, France. RI collatz, george/D-5381-2012; Koster, Randal/F-5881-2012; Los, Sietse/G-8985-2012; OI Koster, Randal/0000-0001-6418-6383; Los, Sietse/0000-0002-1325-3555 NR 49 TC 39 Z9 41 U1 4 U2 13 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 1525-755X J9 J HYDROMETEOROL JI J. Hydrometeorol. PD DEC PY 2002 VL 3 IS 6 BP 617 EP 629 DI 10.1175/1525-7541(2002)003<0617:IOTIVO>2.0.CO;2 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 625JV UT WOS:000179814100001 ER PT J AU Jackson, TJ Hsu, AY O'Neill, PE AF Jackson, TJ Hsu, AY O'Neill, PE TI Surface soil moisture retrieval and mapping using high-frequency microwave satellite observations in the Southern Great Plains SO JOURNAL OF HYDROMETEOROLOGY LA English DT Article ID HYDROLOGY EXPERIMENT; DIELECTRIC BEHAVIOR; WATER-CONTENT; WET SOIL; 6.6 GHZ; VEGETATION; EMISSION; PARAMETERS; RADIOMETRY; ROUGHNESS AB Studies have shown the advantages of low-frequency (<5 GHz) microwave sensors for soil moisture estimation. Although higher frequencies have limited soil moisture retrieval capabilities, there is a vast quantity of systematic global high-frequency microwave data that have been collected for 15 yr by the Special Sensor Microwave Imager (SSM/I). SSM/I soil moisture studies have mostly utilized antecedent precipitation indices as validation, while only a few have employed limited ground observations, which were typically not optimal for this particular type of satellite data. In the Southern Great Plains (SGP) hydrology experiments conducted in 1997 and 1999, ground observations of soil moisture were made over an extended region for developing and validating large-scale mapping techniques. Previous studies have indicated the limitations of both the higher-frequency data and models for soil moisture retrieval. Given these limitations, an alternative retrieval technique that utilizes multipolarization observations was implemented and tested for the SGP region. A technique for extracting algorithm parameters from the observations was developed and tested. The algorithm was then used to produce soil moisture maps of the region for the two study periods. C1 USDA ARS, Hydrol & Remote Sensing Lab, Beltsville, MD 20705 USA. NASA, Goddard Space Flight Ctr, Hydrol Sci Branch, Lab Hydrospher Proc, Greenbelt, MD 20771 USA. RP Jackson, TJ (reprint author), USDA ARS, Hydrol & Remote Sensing Lab, 104 Bldg 007,BARC-W, Beltsville, MD 20705 USA. RI O'Neill, Peggy/D-2904-2013 NR 33 TC 38 Z9 40 U1 0 U2 0 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 1525-755X J9 J HYDROMETEOROL JI J. Hydrometeorol. PD DEC PY 2002 VL 3 IS 6 BP 688 EP 699 DI 10.1175/1525-7541(2002)003<0688:SSMRAM>2.0.CO;2 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 625JV UT WOS:000179814100005 ER PT J AU Reichle, RH Walker, JP Koster, RD Houser, PR AF Reichle, RH Walker, JP Koster, RD Houser, PR TI Extended versus ensemble Kalman filtering for land data assimilation SO JOURNAL OF HYDROMETEOROLOGY LA English DT Article ID SEQUENTIAL DATA ASSIMILATION; CATCHMENT-BASED APPROACH; SURFACE SOIL-MOISTURE; ANALYSIS SCHEME; MODEL; METHODOLOGY; RETRIEVAL; VARIANCE AB The performance of the extended Kalman filter (EKF) and the ensemble Kalman filter (EnKF) are assessed for soil moisture estimation. In a twin experiment for the southeastern United States synthetic observations of near-surface soil moisture are assimilated once every 3 days, neglecting horizontal error correlations and treating catchments independently. Both filters provide satisfactory estimates of soil moisture. The average actual estimation error in volumetric moisture content of the soil profile is 2.2% for the EKF and 2.2% (or 2.1%; or 2.0%) for the EnKF with 4 (or 10; or 500) ensemble members. Expected error covariances of both filters generally differ from actual estimation errors. Nevertheless, nonlinearities in soil processes are treated adequately by both filters. In the application presented herein the EKF and the EnKF with four ensemble members are equally accurate at comparable computational cost. Because of its flexibility and its performance in this study, the EnKF is a promising approach for soil moisture initialization problems. C1 NASA, Goddard Space Flight Ctr, Hydrol Sci Branch, Greenbelt, MD 20771 USA. Univ Maryland, Goddard Earth Sci & Technol Ctr, Baltimore, MD 21201 USA. Univ Melbourne, Parkville, Vic 3052, Australia. RP Reichle, RH (reprint author), NASA, Goddard Space Flight Ctr, Hydrol Sci Branch, Code 974,Greenbelt Rd, Greenbelt, MD 20771 USA. RI Reichle, Rolf/E-1419-2012; Koster, Randal/F-5881-2012; Walker, Jeffrey/D-2624-2009; Houser, Paul/J-9515-2013 OI Koster, Randal/0000-0001-6418-6383; Houser, Paul/0000-0002-2991-0441 NR 29 TC 170 Z9 184 U1 0 U2 15 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 1525-755X J9 J HYDROMETEOROL JI J. Hydrometeorol. PD DEC PY 2002 VL 3 IS 6 BP 728 EP 740 DI 10.1175/1525-7541(2002)003<0728:EVEKFF>2.0.CO;2 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 625JV UT WOS:000179814100008 ER PT J AU Litvin, FL Vecchiato, D Demenego, A Karedes, E Hansen, B Handschuh, R AF Litvin, FL Vecchiato, D Demenego, A Karedes, E Hansen, B Handschuh, R TI Design of one stage planetary gear train with improved conditions of load distribution and reduced transmission errors SO JOURNAL OF MECHANICAL DESIGN LA English DT Article ID BEHAVIOR AB The authors propose an approach for the design of one-stage planetary gear train with reduced transmission errors, localized bearing contact and improved conditions of distribution of load between the planetary gears. The planetary gear train is considered as a multi-body mechanical system of rigid bodies. The proposed approach is based: (i) on modification of geometry of gear tooth surfaces, and (ii) minimization and equalization of the backlash between the contacting gear tooth surfaces. The modification of geometry is accomplished: (i) by double-crowning of planetary gears, and (ii) by application of screw involute surfaces of the same direction of screws for the sun and the ring gears. The proposed geometry enables: (i) predesign of parabolic function of transmission errors for reduction of noise and vibration, and (ii) a simple method of regulation and equalization of the backlash between the gear tooth. C1 Univ Illinois, Gear Res Ctr, Chicago, IL 60607 USA. Sikorsky Aircraft Co, Stratford, CT 06615 USA. NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. Army Res Lab, Cleveland, OH 44135 USA. RP Litvin, FL (reprint author), Univ Illinois, Gear Res Ctr, Chicago, IL 60607 USA. NR 15 TC 15 Z9 16 U1 3 U2 12 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA THREE PARK AVE, NEW YORK, NY 10016-5990 USA SN 1050-0472 J9 J MECH DESIGN JI J. Mech. Des. PD DEC PY 2002 VL 124 IS 4 BP 745 EP 752 DI 10.1115/1.1515797 PG 8 WC Engineering, Mechanical SC Engineering GA 625RR UT WOS:000179829800018 ER PT J AU Nikitin, A Brown, LR Fejard, L Charnpion, JP Tyuterev, VG AF Nikitin, A Brown, LR Fejard, L Charnpion, JP Tyuterev, VG TI Analysis of the CH3D nonad from 2000 to 3300 cm(-1) SO JOURNAL OF MOLECULAR SPECTROSCOPY LA English DT Article DE monodeuterated methane; CH3D nonad; infrared; fundamental bands; polyad; positions; intensities ID MULTISPECTRUM FITTING TECHNIQUE; INDUCED SHIFT COEFFICIENTS; ABSOLUTE LINE-INTENSITIES; DIODE-LASER MEASUREMENTS; INFRARED SOLAR SPECTRA; AIR-BROADENED WIDTH; TEMPERATURES RELEVANT; ROTATIONAL ANALYSIS; 3-NU(2) BAND; NU(3) BAND AB As part of the simultaneous analysis of line positions and intensities of the first two polyads of monodeuterated methane, the results achieved for the region 3-5 mum are reported. It involves the three highest fundamentals, (nu(1), nu(2), nu(4)), Overlapped by overtone (2nu(3), 2nu(5), 2nu(6)) and combination (nu(3) + nu(6), nu(3) + nu(5), nu(5) + nu(6)) bands. The theoretical model was based on the global tensorial model implemented in the MIRS package. Some 10 000 line positions and 2400 line intensities have been modeled to +/-0.000 88 cm(-1) and +/-3.6% respectively, using measurements obtained at 0,0056 and 0.011 cm(-1) resolution with the Fourier transform spectrometer at National Solar Observatory located at Kitt Peak. The strongest band in this polyad is nu(4)(E) at 3016.7 cm(-1) with a strength of 6.3 x 10(-18) cm(-1)/(molecule cm(-2)) at 296 K: the weakest band is 2nu(3)(E) at 2597.7 cm(-1) with a strength of 1.9 x 10(-20) cm(-1)/(molecule cm(-2)) at 296 K. The total calculated absorption arising from the CH3D nonad is 8.95 x 10(-18) cm(-1)/(molecule cm(-2)) at 296 K. (C) 2002 Elsevier Science (USA). C1 Russian Acad Sci, Lab Theoret Spect, Inst Atmospher Opt, Tomsk 634055, Russia. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Bourgogne, Phys Lab, UMR 5027, CNRS, F-21078 Dijon, France. Univ Reims, Lab Spect Mol Atmospher, UMR 6089, CNRS, F-21078 Reims, France. RP Nikitin, A (reprint author), Russian Acad Sci, Lab Theoret Spect, Inst Atmospher Opt, Tomsk 634055, Russia. RI Champion, Jean-Paul/C-3963-2009; Nikitin, Andrei/K-2624-2013 OI Nikitin, Andrei/0000-0002-4280-4096 NR 39 TC 46 Z9 46 U1 0 U2 12 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 DEC PY 2002 VL 216 IS 2 BP 225 EP 251 DI 10.1006/jmsp.2002.8566 PG 27 WC Physics, Atomic, Molecular & Chemical; Spectroscopy SC Physics; Spectroscopy GA 631UG UT WOS:000180184700007 ER PT J AU Muller, HSP Cohen, EA Christen, D AF Muller, HSP Cohen, EA Christen, D TI The rotational spectrum of ClClO2 in its v(4)=1 and v(6)=1 vibrationally excited states: An example of strong Coriolis interaction SO JOURNAL OF MOLECULAR SPECTROSCOPY LA English DT Article DE rotational spectroscopy; Coriolis interaction; resonance; hyperfine structure; chlorine oxides; chloryl chloride ID HYPERFINE-STRUCTURE ANALYSIS; = 1 STATES; CHLORYL CHLORIDE; SPECTROSCOPIC CONSTANTS; SUBMILLIMETER-WAVE; MICROWAVE; CL2O2 AB The two lowest vibrational states of (ClClO2)-Cl-35-Cl-35, v(4) = 1 (A') and v(6) = 1 (A"), were investigated between 223 and 500 GHz. More than 250 rotational transitions were recorded with J and K-d up to 71 and 34. respectively. The spectra are heavily perturbed by strong c-type and weaker a-type Coriolis interactions. Near degeneracies of rotational levels of the two vibrational states having DeltaJ = 0, DeltaK(a) = 5 to 1, and DeltaK(a) + DeltaK(c) = odd cause moderate to severe perturbations in the rotational structure, preventing the states front being fit as isolated ones. Distortions in the hyperfine structure facilitated the assignment of rotational quantum numbers. Several resonantly interacting levels with DeltaK(a) = 5 to 2 were accessed, and a number of transitions between the states were observed. While resonant Coriolis interaction with DeltaK(a) = 1 occurs only at K-a > 40, the effects of this interaction are so severe that nonresonant interaction considerably perturbs the highest K-a Q-branches observed, The observed transitions could be fit to within experimental uncertainties employing the first-order Coriolis coupling constants fixed to those from the harmonic force field, sextic distortion constants fixed to those of the ground state, and some higher order Coriolis terms. The energy difference calculated front the fit agrees well with that obtained from the matrix-isolation infrared spectrum. Quadrupole coupling constants were determined for both Cl nuclei and both vibrational states. (C) 2002 Else let Science (USA). C1 Univ Cologne, Inst Phys 1, D-50937 Cologne, Germany. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Tubingen, Inst Phys & Theoret Chem, D-72076 Tubingen, Germany. RP Muller, HSP (reprint author), Univ Cologne, Inst Phys 1, Zulpicher Str 77, D-50937 Cologne, Germany. EM hspm@ph1.uni-koeln.de OI Mueller, Holger/0000-0002-0183-8927 NR 20 TC 5 Z9 5 U1 0 U2 0 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0022-2852 EI 1096-083X J9 J MOL SPECTROSC JI J. Mol. Spectrosc. PD DEC PY 2002 VL 216 IS 2 BP 335 EP 344 DI 10.1006/jmsp.2002.8629 PG 10 WC Physics, Atomic, Molecular & Chemical; Spectroscopy SC Physics; Spectroscopy GA 631UG UT WOS:000180184700018 ER PT J AU Kukhtarev, N Kukhtareva, T Edwards, ME Penn, B Frazier, D Abdeldayem, H Banerjee, PP Hudson, T Friday, WA AF Kukhtarev, N Kukhtareva, T Edwards, ME Penn, B Frazier, D Abdeldayem, H Banerjee, PP Hudson, T Friday, WA TI Photoinduced optical and electrical high-voltage pulsations and pattern formation in photorefractive crystals SO JOURNAL OF NONLINEAR OPTICAL PHYSICS & MATERIALS LA English DT Article DE optical pulsator; photorefractive crystals; dynamic pattern formation ID MODELS AB We review our results on conversion of CW laser Ar-ion beam power into pulsating multichannel outputs: optical, electric and piezoelectric with simultaneous dynamic pattern formation. We show, that electrical pulsations generate high-voltage signals that may be used as a driving voltage for the conventional electro-optical modulator. We have also demonstrated the possibility of synchronization of two optical pulsators, through regulated optical coupling in a photorefractive LiNbO3 crystal. Spatial distribution of scattered light is self-organized in different patterns (hexagonal and cross-type). C1 Alabama A&M Univ, Dept Phys, Normal, AL 35762 USA. NASA, George C Marshall Space Flight Ctr, Space Sci Lab, Huntsville, AL 35812 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Dayton, Dept ECE, Dayton, OH 45469 USA. USA, Aviat & Missile Command, Redstone Arsenal, AL 35898 USA. RP Kukhtarev, N (reprint author), Alabama A&M Univ, Dept Phys, POB 1268, Normal, AL 35762 USA. NR 16 TC 12 Z9 12 U1 0 U2 1 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA JOURNAL DEPT PO BOX 128 FARRER ROAD, SINGAPORE 912805, SINGAPORE SN 0218-8635 J9 J NONLINEAR OPT PHYS JI J. Nonlinear Opt. Phys. Mater. PD DEC PY 2002 VL 11 IS 4 BP 445 EP 453 DI 10.1142/S0218863502001164 PG 9 WC Optics; Physics, Applied SC Optics; Physics GA 649QM UT WOS:000181219500009 ER PT J AU Cucinotta, FA Saganti, PB Wilson, JW Simonsen, LC AF Cucinotta, FA Saganti, PB Wilson, JW Simonsen, LC TI Model predictions and visualization of the particle flux on the surface of Mars SO JOURNAL OF RADIATION RESEARCH LA English DT Article; Proceedings Paper CT 2nd International Workshop on Space Radiation Research CY MAR 11-15, 2002 CL NARA, JAPAN DE Mars; radiation; visualization; particle flux; GCR AB Model calculations of the particle flux on the surface of Mars due to the Galactic Cosmic Rays (GCR) can provide guidance on radiobiological research and shielding design studies in support of Mars exploration science objectives. Particle flux calculations for protons, helium ions, and heavy ions are reported for solar minimum and solar maximum conditions. These flux calculations include a description of the altitude variations on the Martian surface using the data obtained by the Mars Global Surveyor (MGS) mission with its Mars Orbiter Laser Altimeter (MOLA) instrument. These particle flux calculations are then used to estimate the average particle hits per cell at various organ depths of a human body in a conceptual shelter vehicle. The estimated particle hits by protons for an average location at skin depth on the Martian surface are about 10 to 100 particle-hits/cell/year and the particle hits by heavy ions are estimated to be 0.001 to 0.01 particle-hits/cell/year. C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. NASA, Lockheed Space Operat, JSC, Houston, TX 77058 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Saganti, PB (reprint author), NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. NR 14 TC 12 Z9 12 U1 0 U2 2 PU JAPAN RADIATION RESEARCH SOC PI CHIBA PA C/O NAT INST RADIOLOGICAL SCI 9-1 ANAGAWA-4-CHOME INAGE-KU, CHIBA, 263, JAPAN SN 0449-3060 J9 J RADIAT RES JI J. Radiat. Res. PD DEC PY 2002 VL 43 SU S BP S35 EP S39 PG 5 WC Biology; Radiology, Nuclear Medicine & Medical Imaging SC Life Sciences & Biomedicine - Other Topics; Radiology, Nuclear Medicine & Medical Imaging GA 699AK UT WOS:000184033600007 PM 12793727 ER PT J AU De Angelis, G Wilson, JW Clowdsley, MS Nealy, JE Humes, DH Clem, JM AF De Angelis, G Wilson, JW Clowdsley, MS Nealy, JE Humes, DH Clem, JM TI Lunar lava tube radiation safety analysis SO JOURNAL OF RADIATION RESEARCH LA English DT Article; Proceedings Paper CT 2nd International Workshop on Space Radiation Research CY MAR 11-15, 2002 CL NARA, JAPAN DE space radiation; moon; radiation safety; modeling ID COSMIC-RADIATION AB For many years it has been suggested that lava tubes on the Moon could provide an ideal location for a manned lunar base, by providing shelter from various natural hazards, such as cosmic radiation, meteorites, micrometeoroids, and impact crater ejecta, and also providing a natural environmental control, with a nearly constant temperature, unlike that of the lunar surface showing extreme variation in its diurnal cycle. An analysis of radiation safety issues on lunar lava tubes has been performed by considering radiation from galactic cosmic rays (GCR) and Solar Particle Events (SPE) interacting with the lunar surface, modeled as a regolith layer and rock. The chemical composition has been chosen as typical of the lunar re-ions where the largest number of lava tube candidates are found. Particles have been transported all through the regolith and the rock, and received particles flux and doses have been calculated. The radiation safety of lunar lava tubes environments has been demonstrated. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. Old Dominion Univ, Norfolk, VA 23529 USA. Ist Super Sanita, I-00161 Rome, Italy. CNR, Washington, DC 20100 USA. Univ Delaware, Bartol Res Inst, Newark, DE 19716 USA. RP De Angelis, G (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 21 TC 8 Z9 8 U1 0 U2 2 PU JAPAN RADIATION RESEARCH SOC PI CHIBA PA C/O NAT INST RADIOLOGICAL SCI 9-1 ANAGAWA-4-CHOME INAGE-KU, CHIBA, 263, JAPAN SN 0449-3060 J9 J RADIAT RES JI J. Radiat. Res. PD DEC PY 2002 VL 43 SU S BP S41 EP S45 PG 5 WC Biology; Radiology, Nuclear Medicine & Medical Imaging SC Life Sciences & Biomedicine - Other Topics; Radiology, Nuclear Medicine & Medical Imaging GA 699AK UT WOS:000184033600008 PM 12793728 ER PT J AU George, K Wu, HL Willingham, V Cucinotta, FA AF George, K Wu, HL Willingham, V Cucinotta, FA TI Analysis of complex-type chromosome exchanges in astronauts' lymphocytes after space flight as a biomarker of High-LET exposure SO JOURNAL OF RADIATION RESEARCH LA English DT Article; Proceedings Paper CT 2nd International Workshop on Space Radiation Research CY MAR 11-15, 2002 CL NARA, JAPAN DE FISH; chromosomes; High-LET; PCC ID IN-SITU HYBRIDIZATION; BLOOD-LYMPHOCYTES; ALPHA-PARTICLES; TIME-COURSE; ABERRATIONS; DAMAGE AB High-LET radiation is more efficient in producing complex-type chromosome exchanges than sparsely ionizing radiation, and this can potentially be used as a biomarker of radiation quality. To investigate if complex chromosome exchanges are induced by the high-LET component of space radiation exposure, damage was assessed in astronauts' blood lymphocytes before and after long duration missions of 3-4 months. The frequency of simple translocations increased significantly for most of the crewmembers studied. However, there were few complex exchanges detected and only one crewmember had a significant increase after flight. It has been suggested that the yield of complex chromosome damage could be underestimated when analyzing metaphase cells collected at one time point after irradiation, and analysis of chemically-induced PCC may be more accurate since problems with complicated cell-cycle delays are avoided. However, in this case the yields of chromosome damage were similar for metaphase and PCC analysis of astronauts' lymphocytes. It appears that the use of complex-type exchanges as biomarker of radiation quality in vivo after low-dose chronic exposure in mixed radiation fields is hampered by statistical uncertainties. C1 Wyle Life Sci, Houston, TX USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP George, K (reprint author), Wyle Life Sci, Houston, TX USA. NR 18 TC 5 Z9 8 U1 0 U2 0 PU JAPAN RADIATION RESEARCH SOC PI CHIBA PA C/O NAT INST RADIOLOGICAL SCI 9-1 ANAGAWA-4-CHOME INAGE-KU, CHIBA, 263, JAPAN SN 0449-3060 J9 J RADIAT RES JI J. Radiat. Res. PD DEC PY 2002 VL 43 SU S BP S129 EP S132 PG 4 WC Biology; Radiology, Nuclear Medicine & Medical Imaging SC Life Sciences & Biomedicine - Other Topics; Radiology, Nuclear Medicine & Medical Imaging GA 699AK UT WOS:000184033600025 PM 12793745 ER PT J AU Kawata, T Ito, H Motoori, K Ueda, T Shigematsu, N Furusawa, Y Durante, M George, K Wu, HL Cucinotta, FA AF Kawata, T Ito, H Motoori, K Ueda, T Shigematsu, N Furusawa, Y Durante, M George, K Wu, HL Cucinotta, FA TI Induction of chromatin damage and distribution of isochromatid breaks in human fibroblast cells exposed to heavy ions SO JOURNAL OF RADIATION RESEARCH LA English DT Article; Proceedings Paper CT 2nd International Workshop on Space Radiation Research CY MAR 11-15, 2002 CL NARA, JAPAN DE high-LET radiation; premature chromosome condensation isochromatid break; calyculin A ID PREMATURE CHROMOSOME CONDENSATION; MAMMALIAN-CELLS; ALPHA-PARTICLES; HIGH-LET; V79 CELLS; INACTIVATION; ABERRATIONS; INTERPHASE; MUTATION; BEAMS AB The frequency of chromatid breaks and the distribution of isochromatid breaks were measured in G2-phase normal human fibroblasts prematurely condensed a short time after exposure to low- or high-LET radiations. The average number of isochromatid breaks from a single particle traversal increased with increasing LET values, while the average number of chromatid-type breaks appeared to reach a plateau. The distribution of isochromatid breaks after high-LET iron particles exposure was overdispersed compared to gamma-rays, indicating that a single iron particle traversal through a cell nucleus can produce multiple isochromatid breaks. C1 Chiba Univ, Grad Sch Med, Dept Radiol, Chuo Ku, Chiba 2608670, Japan. Keio Univ, Sch Med, Dept Radiol, Shinjuku Ku, Tokyo 1608582, Japan. Natl Inst Radiol Sci, Heavy Ion Radiobiol Res Grp, Inage Ku, Chiba 2638555, Japan. Univ Naples Federico II, Dipartimento Sci Fis, I-80126 Naples, Italy. NASA, Lyndon B Johnson Space Ctr, Radiat Biophys Lab, Houston, TX 77058 USA. RP Kawata, T (reprint author), Chiba Univ, Grad Sch Med, Dept Radiol, Chuo Ku, 1-8-1 Inohana, Chiba 2608670, Japan. RI Shigematsu, Naoyuki/B-9374-2014; Durante, Marco/K-1315-2014 NR 28 TC 6 Z9 7 U1 0 U2 3 PU JAPAN RADIATION RESEARCH SOC PI CHIBA PA C/O NAT INST RADIOLOGICAL SCI 9-1 ANAGAWA-4-CHOME INAGE-KU, CHIBA, 263, JAPAN SN 0449-3060 J9 J RADIAT RES JI J. Radiat. Res. PD DEC PY 2002 VL 43 SU S BP S169 EP S173 PG 5 WC Biology; Radiology, Nuclear Medicine & Medical Imaging SC Life Sciences & Biomedicine - Other Topics; Radiology, Nuclear Medicine & Medical Imaging GA 699AK UT WOS:000184033600033 PM 12793753 ER PT J AU Saganti, PB Cucinotta, FA Wilson, JW Schimmerling, W AF Saganti, PB Cucinotta, FA Wilson, JW Schimmerling, W TI Visualization of particle flux in the human body on the surface of Mars SO JOURNAL OF RADIATION RESEARCH LA English DT Article; Proceedings Paper CT 2nd International Workshop on Space Radiation Research CY MAR 11-15, 2002 CL NARA, JAPAN DE Mars; radiation; human body; visualization; GCR AB For a given galactic cosmic ray (GCR) environment, information on the particle flux of protons, alpha particles, and heavy ions, that varies with respect to the topographical altitude on the Martian surface, are needed for planning exploration missions to Mars. The Mars Global Surveyor (MGS) mission with its Mars Orbiter Laser Altimeter (MOLA) instrument has been providing precise topographical surface map of the Mars. With this topographical data, the particle flux at the Martian surface level through the CO2 atmospheric shielding for solar minimum and solar maximum conditions are calculated. These particle flux calculations are then transported first through an anticipated shielding of a conceptual shelter with several water equivalent shield values (up to 50 g/cm(2) of water in steps of 5 g/cm(2)) considered to represent a surface habitat, and then into the human body. Model calculations are accomplished utilizing the HZETRN, QMSFRG, and SUM-MARS codes. Particle flux calculations for 12 different locations in the human body were considered from skin depth to the internal organs including the blood-forming organs (BFO). Visualization of particle flux in the human body at different altitudes on the Martian surface behind a known shielding is anticipated to provide guidance for assessing radiation environment risk on the Martian surface for future human missions. C1 NASA, Lyndon B Johnson Space Ctr, Lockheed Martin Space Operat, Houston, TX 77058 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. NASA Headquarters, Washington, DC 20546 USA. RP Saganti, PB (reprint author), NASA, Lyndon B Johnson Space Ctr, Lockheed Martin Space Operat, Houston, TX 77058 USA. NR 19 TC 9 Z9 9 U1 0 U2 1 PU JAPAN RADIATION RESEARCH SOC PI CHIBA PA C/O NAT INST RADIOLOGICAL SCI 9-1 ANAGAWA-4-CHOME INAGE-KU, CHIBA, 263, JAPAN SN 0449-3060 J9 J RADIAT RES JI J. Radiat. Res. PD DEC PY 2002 VL 43 SU S BP S119 EP S124 PG 6 WC Biology; Radiology, Nuclear Medicine & Medical Imaging SC Life Sciences & Biomedicine - Other Topics; Radiology, Nuclear Medicine & Medical Imaging GA 699AK UT WOS:000184033600023 PM 12793743 ER PT J AU Wilson, JW Tripathi, RK Qualls, GD Cucinotta, FA Prael, RE Norbury, JW Heinbockel, JH Tweed, J De Angelis, G AF Wilson, JW Tripathi, RK Qualls, GD Cucinotta, FA Prael, RE Norbury, JW Heinbockel, JH Tweed, J De Angelis, G TI Advances in space radiation shielding codes SO JOURNAL OF RADIATION RESEARCH LA English DT Article; Proceedings Paper CT 2nd International Workshop on Space Radiation Research CY MAR 11-15, 2002 CL NARA, JAPAN DE space; radiation; high-energy ions ID TRANSPORT; SHUTTLE AB Early space radiation shield code development relied on Monte Carlo methods and made important contributions to the space program. Monte Carlo methods have resorted to restricted one-dimensional problems leading to imperfect representation of appropriate boundary conditions. Even so, intensive computational requirements resulted and shield evaluation was made near the end of the design process. Resolving shielding issues usually had a negative impact on the design. Improved spacecraft shield design requires early entry of radiation constraints into the design process to maximize performance and minimize costs. As a result, we have been investigating high-speed computational procedures to allow shield analysis from the preliminary concept to the final design. For the last few decades, we have pursued deterministic solutions of the Boltzmann equation allowing field mapping within the International Space Station (ISS) in tens of minutes using standard Finite Element Method (FEM) geometry common to engineering design methods. A single ray trace in such geometry requires 14 milliseconds and limits application of Monte Carlo methods to such engineering models. A potential means of improving the Monte Carlo efficiency in coupling to spacecraft geometry is given. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Univ Wisconsin, Milwaukee, WI 53201 USA. Old Dominion Univ, Norfolk, VA 23529 USA. RP Wilson, JW (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 21 TC 12 Z9 12 U1 0 U2 1 PU JAPAN RADIATION RESEARCH SOC PI CHIBA PA C/O NAT INST RADIOLOGICAL SCI 9-1 ANAGAWA-4-CHOME INAGE-KU, CHIBA, 263, JAPAN SN 0449-3060 J9 J RADIAT RES JI J. Radiat. Res. PD DEC PY 2002 VL 43 SU S BP S87 EP S91 PG 5 WC Biology; Radiology, Nuclear Medicine & Medical Imaging SC Life Sciences & Biomedicine - Other Topics; Radiology, Nuclear Medicine & Medical Imaging GA 699AK UT WOS:000184033600017 PM 12793737 ER PT J AU Wilson, JW Kim, MHY De Angelis, G Cucinotta, FA Yoshizawa, N Badavi, FF AF Wilson, JW Kim, MHY De Angelis, G Cucinotta, FA Yoshizawa, N Badavi, FF TI Implementation of Gy-Eq for deterministic effects limitation in shield design SO JOURNAL OF RADIATION RESEARCH LA English DT Article; Proceedings Paper CT 2nd International Workshop on Space Radiation Research CY MAR 11-15, 2002 CL NARA, JAPAN DE space radiation; deterministic effects; shielding ID SPACE RADIATION AB The NCRP has recently defined RBE values and a new quantity (Gy-Eq) for use in estimation of deterministic effects in space shielding and operations. The NCRP's RBE for neutrons is left ambiguous and not fully defined. In the present report we will suggest a complete definition of neutron RBE consistent with the NCRP recommendations and evaluate attenuation properties of deterministic effects (Gy-Eq) in comparison with other dosimetric quantities. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. Coll William & Mary, Williamsburg, VA 23185 USA. Old Dominion Univ, Norfolk, VA 23529 USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. Mitsubishi Res Inst, Chiyoda Ku, Tokyo 1008141, Japan. Christopher Newport Univ, Newport News, VA 23601 USA. RP Wilson, JW (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 15 TC 6 Z9 6 U1 0 U2 2 PU JAPAN RADIATION RESEARCH SOC PI CHIBA PA C/O NAT INST RADIOLOGICAL SCI 9-1 ANAGAWA-4-CHOME INAGE-KU, CHIBA, 263, JAPAN SN 0449-3060 J9 J RADIAT RES JI J. Radiat. Res. PD DEC PY 2002 VL 43 SU S BP S103 EP S106 PG 4 WC Biology; Radiology, Nuclear Medicine & Medical Imaging SC Life Sciences & Biomedicine - Other Topics; Radiology, Nuclear Medicine & Medical Imaging GA 699AK UT WOS:000184033600020 PM 12793740 ER PT J AU Wu, HL Furusawa, Y George, K Kawata, T Cucinotta, FA AF Wu, HL Furusawa, Y George, K Kawata, T Cucinotta, FA TI Analysis of unrejoined chromosomal breakage in human fibroblast cells exposed to low- and high-LET radiation SO JOURNAL OF RADIATION RESEARCH LA English DT Article; Proceedings Paper CT 2nd International Workshop on Space Radiation Research CY MAR 11-15, 2002 CL NARA, JAPAN DE high-LET radiation; chromosome aberration; telomere; unrejoined breaks ID TRUE INCOMPLETE EXCHANGES; IN-SITU HYBRIDIZATION; HUMAN-LYMPHOCYTES; TELOMERIC PNA; IONIZING-RADIATION; V79 CELLS; ABERRATIONS; FRAGMENTS; PROBES AB Reported studies of DNA breakage induced by radiation of various qualities have generally shown a higher fraction of unrejoined residual breaks after high-LET exposure. This observation is supported by the argument that high-LET radiation induced DNA breaks that are more complex in nature and, thus, less likely to be repaired. In most cases the doses used in these studies were very high. We have studied unrejoined chromosome breaks by analyzing chromosome aberrations using a fluorescence in situ hybridization (FISH) technique with a combination of whole chromosome specific probes and probes specific for the telomere region of the chromosomes. Confluent human fibroblast cells (AG1522) were irradiated with gamma rays, 490 MeV/nucleon Si, or with Fe ions at either 200 and 500 MeV/nucleon, and were allowed to repair at 37degreesC for 24 hours after exposure. A chemically induced premature chromosome condensation (PCC) technique was used to condense chromosomes in the G2 phase of the cell cycle. Results showed that the frequency of unrejoined chromosome breaks was higher after high-LET radiation, and the ratio of unrejoined to misrejoined chromosome breaks increased steadily with LET up a peak value at 440 keV/mum. C1 Wyle Labs, Houston, TX USA. Natl Inst Radiol Sci, Chiba, Japan. Chiba Univ, Chiba, Japan. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Wu, HL (reprint author), Wyle Labs, Houston, TX USA. NR 16 TC 7 Z9 7 U1 0 U2 4 PU JAPAN RADIATION RESEARCH SOC PI CHIBA PA C/O NAT INST RADIOLOGICAL SCI 9-1 ANAGAWA-4-CHOME INAGE-KU, CHIBA, 263, JAPAN SN 0449-3060 J9 J RADIAT RES JI J. Radiat. Res. PD DEC PY 2002 VL 43 SU S BP S181 EP S185 PG 5 WC Biology; Radiology, Nuclear Medicine & Medical Imaging SC Life Sciences & Biomedicine - Other Topics; Radiology, Nuclear Medicine & Medical Imaging GA 699AK UT WOS:000184033600035 PM 12793755 ER PT J AU Muller, B Yee, HC AF Muller, Bernhard Yee, H. C. TI Entropy Splitting for High Order Numerical Simulation of Vortex Sound at Low Mach Numbers SO JOURNAL OF SCIENTIFIC COMPUTING LA English DT Article DE Euler equations; entropy splitting; low Mach number aeroacoustics; high order difference method; summation by parts AB Several recent developments in efficient, stable, highly parallelizable high order non-dissipative spatial schemes with characteristic based filters that exhibit low dissipation for long time linear and nonlinear wave propagations are utilized for computational aeroacoustics (CAA). For stability consideration, the Euler equations are split into a conservative and a symmetric non-conservative portion. Due to the large disparity of acoustic and stagnation quantities in low Mach number aeroacoustics, the split Euler equations are formulated in perturbation form to minimize numerical cancellation errors. Spurious oscillations are suppressed by a characteristic-based filter. The method has been applied to accurately simulate the sound emitted by an almost circular Kirchhoff vortex at low Mach numbers. C1 [Muller, Bernhard] Uppsala Univ, Dept Comp Sci, S-75104 Uppsala, Sweden. [Yee, H. C.] NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Muller, B (reprint author), Uppsala Univ, Dept Comp Sci, S-75104 Uppsala, Sweden. EM bernd@tdb.uu.se; yee@nas.nasa.gov FU TFR, the Swedish Research Council for Engineering Sciences FX The research has been supported by TFR, the Swedish Research Council for Engineering Sciences. NR 27 TC 4 Z9 4 U1 0 U2 0 PU SPRINGER/PLENUM PUBLISHERS PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0885-7474 J9 J SCI COMPUT JI J. Sci. Comput. PD DEC PY 2002 VL 17 IS 1-4 BP 181 EP 190 DI 10.1023/A:1015100614522 PG 10 WC Mathematics, Applied SC Mathematics GA V22TP UT WOS:000208297800012 ER PT J AU Montero, RS Llorente, IM Salas, MD AF Montero, Ruben S. Llorente, Ignacio M. Salas, Manuel D. TI A Robust Multigrid Algorithm for the Simulation of a Yawed Flat Plate SO JOURNAL OF SCIENTIFIC COMPUTING LA English DT Article DE Plane implicit smoothers; semicoarsening; robust multigrid; flat plate boundary layer; computational fluid dynamics AB This paper presents a full multigrid solver for the simulation of a flow over a yawed flat plate. The two problems associated with this simulation; boundary layers and entering flows with non-aligned characteristics, have been successfully overcome through the combination of a plane-implicit solver and semi-coarsening. In fact, this multigrid algorithm exhibits a textbook multigrid convergence rate, i.e., the solution of the discrete system of equations is obtained in a fixed amount of computational work, independently of the grid size, grid stretching factor and non-alignment parameter. Also, a parallel variant of the smoother based on a four-color ordering of planes is investigated. C1 [Montero, Ruben S.; Llorente, Ignacio M.] Univ Complutense, Dept Arquitectura Comp & Automat, E-28040 Madrid, Spain. [Salas, Manuel D.] NASA, ICASE, Langley Res Ctr, Hampton, VA 23681 USA. RP Montero, RS (reprint author), Univ Complutense, Dept Arquitectura Comp & Automat, E-28040 Madrid, Spain. EM rubensm@dacya.ucm.es RI Martin Llorente, Ignacio/B-2093-2009; Montero, Ruben/C-5346-2008 OI Martin Llorente, Ignacio/0000-0001-6230-8180; Montero, Ruben/0000-0003-2591-1719 FU National Aeronautics and Space Administration [NAS1-97046]; ICASE, NASA Langley Research Center, Hampton, Virginia [23681-2199]; Spanish research Grant [TIC 99-0474]; US-Spain Joint Commission for Scientific and Technological Cooperation FX This research was supported by the National Aeronautics and Space Administration under NASA Contract No. NAS1-97046 while the first two authors were in residence at ICASE, NASA Langley Research Center, Hampton, Virginia 23681-2199. The first author was also supported in part by the Spanish research Grant TIC 99-0474 and by the US-Spain Joint Commission for Scientific and Technological Cooperation. NR 13 TC 0 Z9 0 U1 0 U2 0 PU SPRINGER/PLENUM PUBLISHERS PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0885-7474 J9 J SCI COMPUT JI J. Sci. Comput. PD DEC PY 2002 VL 17 IS 1-4 BP 481 EP 490 DI 10.1023/A:1015154126334 PG 10 WC Mathematics, Applied SC Mathematics GA V22TP UT WOS:000208297800038 ER PT J AU Dong, XQ Minnis, P Mace, GG Smith, WL Poellot, M Marchand, RT Rapp, AD AF Dong, XQ Minnis, P Mace, GG Smith, WL Poellot, M Marchand, RT Rapp, AD TI Comparison of stratus cloud properties deduced from surface, GOES, and aircraft data during the March 2000 ARM cloud IOP SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID GROUND-BASED MEASUREMENTS; RADIATIVE PROPERTIES; ATMOSPHERIC RADIATION; STRATIFORM CLOUDS; PARAMETERIZATIONS; VERIFICATION; RETRIEVAL AB Low-level stratus cloud microphysical properties derived from surface and Geostationary Operational Environmental Satellite (GOES) data during the March 2000 cloud intensive observational period (IOP) at the Atmospheric Radiation Measurement (ARM) program Southern Great Plains (SGP) site are compared with aircraft in situ measurements. For the surface retrievals, the cloud droplet effective radius and optical depth are retrieved from a delta2-stream radiative transfer model with the input of ground-based measurements, and the cloud liquid water path (LWP) is retrieved from ground-based microwave-radiometer-measured brightness temperature. The satellite results, retrieved from GOES visible, solar-infrared, and infrared radiances, are averaged in a 0.5degrees x 0.5degrees box centered on the ARM SGP site. The forward scattering spectrometer probe (FSSP) on the University of North Dakota Citation aircraft provided in situ measurements of the cloud microphysical properties. During the IOP, four low-level stratus cases were intensively observed by the ground- and satellite-based remote sensors and aircraft in situ instruments resulting in a total of 10 h of simultaneous data from the three platforms. In spite of the large differences in temporal and spatial resolution between surface, GOES, and aircraft, the surface retrievals have excellent agreement with the aircraft data overall for the entire 10-h period, and the GOES results agree reasonably well with the surface and aircraft data and have similar trends and magnitudes except for the GOES-derived effective radii, which are typically larger than the surface- and aircraft-derived values. The means and standard deviations of the differences between the surface and aircraft effective radius, LWP, and optical depth are -4% +/- 20.1%, -1% +/- 31.2%, and 8% +/- 29.3%, respectively; while their correlation coefficients are 0.78, 0.92, and 0.89, respectively, during the 10-h period. The differences and correlations between the GOES-8 and aircraft results are of a similar magnitude, except for the droplet sizes. The averaged GOES-derived effective radius is 23% or 1.8 mum greater than the corresponding aircraft values, resulting in a much smaller correlation coefficient of 0.18. Additional surface- satellite datasets were analyzed for time periods when the aircraft was unavailable. When these additional results are combined with the retrievals from the four in situ cases, the means and standard deviations of the differences between the satellite-derived cloud droplet effective radius, LWP, and optical depth and their surface- based counterparts are 16% +/- 31.2%, 4% +/- 31.6%, and -6% +/- 39.9%, respectively. The corresponding correlation coefficients are 0.24, 0.88, and 0.73. The frequency distributions of the two datasets are very similar indicating that the satellite retrieval method should be able to produce reliable statistics of boundary layer cloud properties for use in climate and cloud process models. C1 Univ N Dakota, Dept Atmospher Sci, Grand Forks, ND 58202 USA. Univ Utah, Dept Meteorol, Salt Lake City, UT 84112 USA. NASA, Langley Res Ctr, Hampton, VA 23665 USA. US DOE, Pacific NW Natl Lab, Richland, WA USA. Analyt Serv & Mat Inc, Hampton, VA USA. RP Dong, XQ (reprint author), Univ N Dakota, Dept Atmospher Sci, 4149 Campus Rd,Clifford Hall 400,Box 9006, Grand Forks, ND 58202 USA. RI Rapp, Anita/G-8845-2012; Minnis, Patrick/G-1902-2010; OI Minnis, Patrick/0000-0002-4733-6148; Dong, Xiquan/0000-0002-3359-6117 NR 29 TC 55 Z9 58 U1 1 U2 6 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PD DEC PY 2002 VL 59 IS 23 BP 3265 EP 3284 DI 10.1175/1520-0469(2002)059<3265:COSCPD>2.0.CO;2 PG 20 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 613TJ UT WOS:000179147300001 ER PT J AU Stevens, DE Ackerman, AS Bretherton, CS AF Stevens, DE Ackerman, AS Bretherton, CS TI Effects of domain size and numerical resolution on the simulation of shallow cumulus convection SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID LARGE-EDDY SIMULATIONS; MARINE BOUNDARY-LAYER; STRATOCUMULUS; INSTABILITY; ENTRAINMENT; CLOUDINESS; TRANSPORTS; MODELS; OCEAN AB The authors present three-dimensional numerical simulations of oceanic trade cumulus clouds underlying stratocumulus clouds. The case studied is a Global Energy and Water Experiment (GEWEX) Cloud System Study (GCSS) model intercomparison that is loosely based on observed conditions during the Atlantic Trade Cumulus Experiment (ATEX). It is motivated by the importance of this cloud type to global cloud radiative forcing, and their role as a feeder system for deep convection in the Tropics. This study focuses on the sensitivity of the modeled cloud field to the domain size and the grid spacing. Domain widths from 6.5 to 20 km and horizontal grid spacings ranging from 10 to 80 m, with corresponding vertical grid spacing ranging from 5 to 40 m, are studied, involving massively parallel computations on up to 2.5 billion grid cells. The combination of large domain size and small grid resolution provides an unprecedented perspective on this type of convection. The mean stratocumulus cloud fraction, optical depth, and vertical fluxes of heat, moisture, and momentum are found to be quite sensitive to both the domain size and the resolution. The sensitivities are associated with a strong feedback between cloud fraction, cloud-top radiative cooling, and entrainment. The properties of individual cumulus clouds rising into the stratocumulus are less affected than the stratocumulus clouds. The simulations with 80-m horizontal by 40-m vertical resolution are clearly under-resolved, with distinctly different distributions of liquid water within the clouds. Increasing the resolution to finer than 40 m horizontal/20 m vertical affects the inversion structure and entrainment processes somewhat, but has less impact on the structure of individual clouds. Large-domain simulations exhibit mesoscale structure in the cloud organization and liquid water path. This mesoscale variability feeds back on the domain-mean properties through the cloud-radiative feedback. These simulations suggest that very large computations are required to obtain meaningful cloud statistics for this case. C1 Lawrence Livermore Natl Lab, Ctr Appl Sci Comp, Div Atmospher Sci, Livermore, CA 94551 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ Washington, Dept Atmospher Sci, Seattle, WA 98195 USA. RP Stevens, DE (reprint author), Lawrence Livermore Natl Lab, Ctr Appl Sci Comp, Div Atmospher Sci, L-98, Livermore, CA 94551 USA. RI Ackerman, Andrew/D-4433-2012 OI Ackerman, Andrew/0000-0003-0254-6253 NR 24 TC 63 Z9 63 U1 1 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 DEC PY 2002 VL 59 IS 23 BP 3285 EP 3301 DI 10.1175/1520-0469(2002)059<3285:EODSAN>2.0.CO;2 PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 613TJ UT WOS:000179147300002 ER PT J AU Heymsfield, AJ Bansemer, A Field, PR Durden, SL Stith, JL Dye, JE Hall, W Grainger, CA AF Heymsfield, AJ Bansemer, A Field, PR Durden, SL Stith, JL Dye, JE Hall, W Grainger, CA TI Observations and parameterizations of particle size distributions in deep tropical cirrus and stratiform precipitating clouds: Results from in situ observations in TRMM field campaigns SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID RADAR REFLECTIVITY; ICE; EVOLUTION; SNOW; CUMULONIMBUS; KWAJALEIN; AIRCRAFT; SPECTRA; SYSTEM; STORMS AB This study reports on the evolution of particle size distributions (PSDs) and habits as measured during slow, Lagrangian-type spiral descents through deep subtropical and tropical cloud layers in Florida, Brazil, and Kwajalein, Marshall Islands, most of which were precipitating. The objective of the flight patterns was to learn more about how the PSDs evolved in the vertical and to obtain information of the vertical structure of microphysical properties. New instrumentation yielding better information on the concentrations of particles in the size (D) range between 0.2 and 2 cm, as well as improved particle imagery, produced more comprehensive observations for tropical stratiform precipitation regions and anvils than have been available previously. Collocated radar observations provided additional information on the vertical structure of the cloud layers sampled. Most of the spirals began at cloud top, with temperatures (T) as low as -50degreesC, and ended at cloud base or below the melting layer (ML). The PSDs broadened from cloud top toward cloud base, with the largest particles increasing in size from several millimeters at cloud top, to 1 cm or larger toward cloud base. Some continued growth was noted in the upper part of the ML. Concentrations of particles less than 1 mm in size decreased with decreasing height. The result was a consistent change in the PSDs in the vertical. Similarly, systematic changes in the size dependence of the particle cross-sectional area was noted with decreasing height. Aggregation-as ascertained from both the changes in the PSDs and evolution of particle habits as observed in high detail with the cloud particle imager (CPI) probe-was responsible for these trends. The PSDs were generally well-represented by gamma distributions of the form N = N0GammaDmu--l-lambdaGammaD that were fitted to the PSDs over 1-km horizontal intervals throughout the spirals. The intercept (N-0Gamma), slope (lambda(Gamma)), and dispersion (mu) values were derived for each PSD. Exponential curves (N = N0(Gamma)e(-lambdaD); mu = 0) were also fitted to the distributions. The lambda(Gamma) values for given spirals varied systematically with temperature as did the values of lambda (exponential), and the data generally conformed to values found in previous studies involving exponential fits to size distributions in midlatitude frontal and cirrus layers. Considerable variability often noted in the PSD properties during the loops of individual spirals was manifested primarily in large changes in N-0Gamma and N-0, but mu, lambda(Gamma), and lambda remained fairly stable. Temperature is not found to be the sole factor controlling lambda(Gamma) or lambda, but is a primary one. Direct relationships were found between lambda(Gamma) and N-0Gamma, or lambda(Gamma) and mu, for the gamma distributions, and lambda and N-0 for the exponential. The latter relationship was not found as distinctly in earlier studies; observed PSDs in this study had better fidelity with less scatter. The mu values changed monotonically with T over the range of temperatures and were directly related to N-0Gamma or lambda(Gamma), thereby reducing the number of variables in the PSD functional equation to two. In the upper part of the ML, N-0, and lambda continued to decrease, and in the lower part these values began to increase as the largest particles melted. General expressions relating various bulk microphysical, radar, and radiative-transfer-related variables to N-0Gamma and lambda(Gamma) were developed; they are useful for both tropical and midlatitude clouds. These relationships facilitate the specification of a number of bulk properties in cloud and climate models. The results presented in this paper apply best to temperatures between 0degrees and -40degreesC, for which the measured radar reflectivities fall in the range of 0 to 25 dBZ(e). C1 Natl Ctr Atmospher Res, Boulder, CO 80307 USA. Met Off, Meteorol Res Flight, Farnborough, Hants, England. Jet Prop Lab, Pasadena, CA USA. Univ N Dakota, Grand Forks, ND 58201 USA. RP Heymsfield, AJ (reprint author), 3450 Mitchell Lane,POB 3000, Boulder, CO 80301 USA. RI Heymsfield, Andrew/E-7340-2011; Field, Paul/B-1692-2009 OI Field, Paul/0000-0001-8528-0088 NR 37 TC 174 Z9 182 U1 3 U2 17 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 DEC PY 2002 VL 59 IS 24 BP 3457 EP 3491 DI 10.1175/1520-0469(2002)059<3457:OAPOPS>2.0.CO;2 PG 35 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 622CW UT WOS:000179629800003 ER PT J AU Johnson, DE Tao, WK Simpson, J Sui, CH AF Johnson, DE Tao, WK Simpson, J Sui, CH TI A study of the response of deep tropical clouds to large-scale thermodynamic forcings. Part I: Modeling strategies and simulations of TOGA COARE convective systems SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID CUMULUS ENSEMBLE MODEL; ADVECTION TRANSPORT ALGORITHM; SMALL IMPLICIT DIFFUSION; LATENT-HEAT RELEASE; BULK ICE SCHEME; NUMERICAL-SIMULATION; RESOLVING MODEL; PHASE-III; RADIATION INTERACTION; MESOSCALE PROCESSES AB Interactions between deep tropical clouds over the western Pacific warm pool and the larger-scale environment are key to understanding climate change. Cloud models are an extremely useful tool in simulating and providing statistical information on heat and moisture transfer processes between cloud systems and the environment, and can therefore be utilized to substantially improve cloud parameterizations in climate models. In this paper, the Goddard Cumulus Ensemble (GCE) cloud-resolving model is used in multiday simulations of deep tropical convective activity over the Tropical Ocean Global Atmosphere Coupled Ocean-Atmosphere Response Experiment (TOGA COARE). Large-scale temperature and moisture advective tendencies, and horizontal momentum from the TOGA COARE Intensive Flux Array region, are applied to the GCE version that incorporates cyclical boundary conditions. Sensitivity experiments show that the horizontal extent (size) of the domain produces the largest response to domain-mean temperature and moisture deviations, as well as cloudiness, in comparison with grid horizontal or vertical resolution, and advection scheme. It is found that a domain size of at least 512 km is needed to adequately contain the convective cloud features and to replicate both the eastward and westward movements of the observed precipitating systems. The control experiment shows that the atmospheric heating and moistening is primarily a response to cloud latent processes of condensation/evaporation, and deposition/sublimation. Air-sea exchange of heat and moisture is found to be of secondary importance, while the net radiational heating-cooling is small except above cloud tops. A convective-stratiform breakdown of the precipitating systems shows that while 55% of the total rainfall occurs in convective regions, 90% of the total rainfall coverage occurs in stratiform regions. The simulated rainfall and atmospheric heating and moistening rates agree very well with observations, and the results compare favorably to other models simulating this case. C1 NASA, Goddard Space Flight Ctr, Mesoscale Atmospher Proc Branch, Atmospheres Lab, Greenbelt, MD 20771 USA. Univ Maryland Baltimore Cty, Goddard Earth Sci & Technol Ctr, Baltimore, MD 21228 USA. RP Johnson, DE (reprint author), NASA, Goddard Space Flight Ctr, Mesoscale Atmospher Proc Branch, Atmospheres Lab, Code 912, Greenbelt, MD 20771 USA. OI SUI, CHUNG-HSIUNG/0000-0003-2842-5660 NR 76 TC 41 Z9 41 U1 0 U2 3 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PD DEC PY 2002 VL 59 IS 24 BP 3492 EP 3518 DI 10.1175/1520-0469(2002)059<3492:ASOTRO>2.0.CO;2 PG 27 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 622CW UT WOS:000179629800004 ER PT J AU Knyazikhin, Y Marshak, A Wiscombe, WJ Martonchik, JV Myneni, RB AF Knyazikhin, Y Marshak, A Wiscombe, WJ Martonchik, JV Myneni, RB TI A missing solution to the transport equation and its effect on estimation of cloud absorptive properties SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID MARINE STRATOCUMULUS CLOUDS; ATMOSPHERIC SOLAR ABSORPTION; SHORTWAVE EXPERIMENT ARESE; RADIATION; AIRCRAFT; SIGNATURE; MODELS; BUDGET AB Most of the existing cloud radiation models treat liquid water drops of a variety of sizes as an ensemble of particles. The ensemble approach assumes that all drop sizes are well represented in an elementary volume, and its scattering and absorbing properties can be accurately specified through the use of the drop size probability density distribution function. The concentration of large drops, however, can be so low that a chance to capture them in the elementary volume is rare. Thus the drop ensemble assumption is not always true, though classical radiative transfer theory uses this assumption to simplify the radiative transfer process, as if scattering takes place from an "average drop'' rather than from a particular drop. The theoretical analysis presented in this paper demonstrates that if a cumulative distribution function is used to describe drop size variability with jumps accounting for the probability of finding large drops in the elementary volume, one obtains an extra term, the Green's function, in the solution of the radiative transfer equation. The analysis of data on cloud drop size distribution acquired during the First International Satellite Cloud Climatology Project (ISCCP) Research Experiment (FIRE) field campaign clearly shows jumps in the cumulative drop size distribution; the magnitudes of the jumps are related to the frequencies of large drop occurrence. This discontinuity is primarily responsible for the additional terms that must be added to the solution to properly account for the photon interaction with the large drops. The enhancement of cloud absorption due to accounting for the "missing solution'' exhibits a jump-like response to continuous variation in the concentration of large drops and may exceed the enhancement predicted by the ensemble-based models. The results presented here indicate that the missing term might be plausible to explain the enhanced value of the ratio of the shortwave cloud forcing at the surface to the forcing at top of the atmosphere. C1 Boston Univ, Dept Geog, Boston, MA 02215 USA. Univ Maryland Baltimore Cty, Joint Ctr Earth Syst Technol, Baltimore, MD 21228 USA. NASA, Goddard Space Flight Ctr, Climat & Radiat Branch, Greenbelt, MD 20771 USA. CALTECH, Jet Prop Lab, Pasadena, CA USA. RP Knyazikhin, Y (reprint author), Boston Univ, Dept Geog, 675 Commonwealth Ave, Boston, MA 02215 USA. RI Wiscombe, Warren/D-4665-2012; Marshak, Alexander/D-5671-2012; Myneni, Ranga/F-5129-2012 OI Wiscombe, Warren/0000-0001-6844-9849; NR 37 TC 9 Z9 9 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 DEC PY 2002 VL 59 IS 24 BP 3572 EP 3585 DI 10.1175/1520-0469(2002)059<3572:AMSTTT>2.0.CO;2 PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 622CW UT WOS:000179629800008 ER PT J AU Lau, KM Weng, HY AF Lau, KM Weng, HY TI Recurrent teleconnection patterns linking summertime precipitation variability over East Asia and North America SO JOURNAL OF THE METEOROLOGICAL SOCIETY OF JAPAN LA English DT Article ID MONSOON-ENSO RELATIONSHIP; SEA-SURFACE TEMPERATURE; US PRECIPITATION; SST VARIABILITY; INDIAN MONSOON; UNITED-STATES; EL-NINO; PACIFIC; RAINFALL; MODES AB From analyses based on Singular Value Decomposition of rainfall and 500 hPa geopotential height anomalies, we have identified two atmospheric teleconnection pattern linking interannual variability of summertime precipitation over East Asia and the continental United States. The first pattern is associated with enhanced rainfall over the Yangtze River region to above-normal rainfall over the US northern Great Plains and the Midwest, and reduced rainfall over the Atlantic coast. It features zonally elongated 500 hPa height anomalies over the subtropical and extratropical western North Pacific coupled to a regional circulation pattern over North American that regulates moisture transport from the Gulf of Mexico to the Northern Great Plains. The second pattern shows enhanced rainfall anomalies over the Huaihe River, northeastern and southern China and deficient rainfall over the central US. It connects the East Asian and North American continents via a pan-Pacific wavetrain signal, possibly stemming from Rossby wave dispersion from fluctuations of large-scale heat sources, and sinks in the Indo-Pacific region. Examination of associated sea surface temperature variability in the North Pacific suggests that the first pattern may be influenced by El Nino in the preceding spring, but becomes increasing decoupled from tropical SST during the summer and fall. However, the second pattern has no significant relationship with El Nino. Analysis of extreme rainfall statistics between regions in East Asia and North America suggests that occurrence of the aforementioned teleconnection patterns is associated with increased probability for extreme rainfall events over the Yangtze River Valley, coupled to increased probability of anomalies of the same sign over the US Midwest, and of the opposite sign over the US Mid-Atlantic coast. Our results suggest that the summertime teleconnection patterns should be further explored for additional sources of potential predictability of summertime floods or droughts over regions of East Asia and North America. C1 NASA, Goddard Space Flight Ctr, Atmospheres Lab, Climata & Radiat Branch, Greenbelt, MD 20771 USA. Univ Tokyo, Ctr Climate Syst Res, Tokyo, Japan. RP Lau, KM (reprint author), NASA, Goddard Space Flight Ctr, Atmospheres Lab, Climata & Radiat Branch, Code 913, Greenbelt, MD 20771 USA. RI Lau, William /E-1510-2012 OI Lau, William /0000-0002-3587-3691 NR 27 TC 73 Z9 85 U1 0 U2 9 PU METEOROLOGICAL SOC JPN PI TOKYO PA C/O JPN METEOROL AGENCY 1-3-4 OTE-MACHI, CHIYODA-KU, TOKYO, JAPAN SN 0026-1165 J9 J METEOROL SOC JPN JI J. Meteorol. Soc. Jpn. PD DEC PY 2002 VL 80 IS 6 BP 1309 EP 1324 DI 10.2151/jmsj.80.1309 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 645NE UT WOS:000180983800001 ER PT J AU Walsh, BM McMahon, J Edwards, WC Barnes, NP Equall, RW Hutcheson, RL AF Walsh, BM McMahon, J Edwards, WC Barnes, NP Equall, RW Hutcheson, RL TI Spectroscopic characterization of Nd : Y2O3: application toward a differential absorption lidar system for remote sensing of ozone SO JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS LA English DT Article ID LASERS; SINGLE; Y2O3; YAG AB Neodymium-doped yttria (Nd:Y2O3) is investigated as a solid-state laser material for frequency-tripled generation of ultraviolet laser wavelengths for use in remote sensing of ozone. Emphasis is placed both on the spectroscopy of the fundamental wavelengths at similar to0.914 mum and similar to0.946 mum to assess their feasibility for laser oscillation and on the absorption spectroscopy in the 0.8-mum wavelength region for determination of suitable pump sources. The temperature dependence of the emission and absorption characteristics of Nd:Y2O3 are examined, since aggressive cooling may be required for efficient similar to0.914-mum lasing due to its quasi four-level nature. Data for flash-lamp-pumped laser performance on the F-4(3/2) --> I-4(11/2) is presented for Nd:Y2O3 and compared with Nd:YAG. Diode-pumped threshold-fluence and threshold-pump energy estimates for Nd:Y2O3 lasing on the F-4(3/2), I-4(9/2) at 0.914 mum and 0.946 mum are calculated based on the data presented here. The measurements presented here for the Nd:Y2O3 indicate favorable absorption and emission properties. Favorable absorption properties in the similar to0.8-mum pump wavelength are compatible with a variety of potential pump sources. Favorable emission properties at reduced temperatures near 150 K indicate that Nd:Y2O3 operating at 0.914 mum and 0.946 mum will have normal-mode laser thresholds similar to that of room-temperature Nd:YAG operating at 0.946 mum. In Q-switched operation, however, Nd:Y2O3 is predicted to exceed the performance of Nd:YAG due to the lower 1.06/0.94 cross-section ratio, which helps to limit amplified spontaneous-emission effects. Although Nd:Y2O3 is not a new material, it has not been the topic of study due to growth problems associated with its high melting point. New advances in growth techniques and the favorable spectroscopic features of Nd:Y2O3 have inspired a new examination of this material. (C) 2002 Optical Society of America. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. Schafer Corp, Arlington, VA 22209 USA. Sci Mat, Bozeman, MT 59715 USA. RP Walsh, BM (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 25 TC 43 Z9 44 U1 3 U2 12 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 0740-3224 J9 J OPT SOC AM B JI J. Opt. Soc. Am. B-Opt. Phys. PD DEC PY 2002 VL 19 IS 12 BP 2893 EP 2903 DI 10.1364/JOSAB.19.002893 PG 11 WC Optics SC Optics GA 625PN UT WOS:000179825000008 ER PT J AU Shortt, BJ van der Burgt, PJM Giammanco, F AF Shortt, BJ van der Burgt, PJM Giammanco, F TI Resonant three-photon ionization of atomic hydrogen in a finite-bandwidth laser field and a static electric field SO LASER PHYSICS LA English DT Article ID MULTIPHOTON IONIZATION; TIME; 2-PHOTON; 3-PHOTON AB We derive a set of density matrix equations describing laser photo-excitation and ionization of atomic hydrogen in the presence of an external electric field. The equations are relevant as a description of multiphoton ionization of hydrogen (or deuterium) atoms in laser-produced transient plasmas. The laser wavelength is 243 nm, so that the photoionization is resonant with the 2s(1/2) level. The electric field causes Stark mixing of the 2s(1/2) level with the 2p(1/2) and 2p(3/2) levels. Because the electric field is taken in the same direction as the linear polarization of the laser, only states with equal m(j) are coupled, and the atom can be described with a four-level density matrix. The laser bandwidth is taken into account by using the stochastic model of a chaotic laser field introduced by Zoller [1]. We present a few calculations of the probabilities for ionization and excitation of a single hydrogen atom as a function of laser intensity and wavelength. C1 INFM, I-56126 Pisa, Italy. Univ Pisa, Dipartimento Fis, I-56126 Pisa, Italy. Natl Univ Ireland, Dept Expt Phys, Maynooth, Kildare, Ireland. RP Shortt, BJ (reprint author), CALTECH, Jet Prop Lab, Atom & Mol Collis Team, MS 121-104,4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI van der Burgt, Peter/J-6792-2015 NR 13 TC 2 Z9 2 U1 0 U2 0 PU INTERPERIODICA PI BIRMINGHAM PA PO BOX 1831, BIRMINGHAM, AL 35201-1831 USA SN 1054-660X J9 LASER PHYS JI Laser Phys. PD DEC PY 2002 VL 12 IS 12 BP 1402 EP 1409 PG 8 WC Optics; Physics, Applied SC Optics; Physics GA 629DV UT WOS:000180035900003 ER PT J AU DellaCorte, C AF DellaCorte, C TI Commercialization: a long road worth taking SO LUBRICATION ENGINEERING LA English DT Editorial Material C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP DellaCorte, C (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SOC TRIBOLOGISTS & LUBRICATION ENGINEERS PI PARK RIDGE PA 840 BUSSE HIGHWAY, PARK RIDGE, IL 60068 USA SN 0024-7154 J9 LUBR ENG JI Lubric. Eng. PD DEC PY 2002 VL 58 IS 12 BP 3 EP 3 PG 1 WC Engineering, Mechanical SC Engineering GA 632DZ UT WOS:000180209600001 ER PT J AU Barshi, I Healy, AF AF Barshi, I Healy, AF TI The effects of mental representation on performance in a navigation task SO MEMORY & COGNITION LA English DT Article ID SHORT-TERM-MEMORY; VISUOSPATIAL WORKING-MEMORY; NARRATIVE COMPREHENSION; SITUATION MODELS; INDIVIDUAL-DIFFERENCES; INTERFERENCE; LANGUAGE; CONSTRUCTION; RETENTION; CAPACITY AB In three experiments, we investigated the mental representations employed when instructions were followed that involved navigation in a space displayed as a grid on a computer screen. Performance was affected much more by the number of instructional units than by the number of words per unit. Performance in a three-dimensional space was independent of the number of dimensions along which participants navigated. However, memory for and accuracy in following the instructions were reduced when the task required mentally representing a three-dimensional space, as compared with representing a two-dimensional space, although the words used in the instructions were identical in the two cases. These results demonstrate the interdependence of verbal and spatial memory representations, because individuals' immediate memory for verbal navigation instructions is affected by their mental representation of the space referred to by the instructions. C1 Univ Colorado, Boulder, CO 80309 USA. RP Barshi, I (reprint author), NASA, Ames Res Ctr, Human Factors Res & Technol Div, Mail Stop 262-4, Moffett Field, CA 94035 USA. NR 44 TC 22 Z9 23 U1 0 U2 0 PU PSYCHONOMIC SOC INC PI AUSTIN PA 1710 FORTVIEW RD, AUSTIN, TX 78704 USA SN 0090-502X J9 MEM COGNITION JI Mem. Cogn. PD DEC PY 2002 VL 30 IS 8 BP 1189 EP 1203 DI 10.3758/BF03213402 PG 15 WC Psychology, Experimental SC Psychology GA 653PE UT WOS:000181444800003 PM 12661851 ER PT J AU Lerch, BA Draper, SL Pereira, JM AF Lerch, BA Draper, SL Pereira, JM TI Conducting high-cycle fatigue strength step tests on gamma TiAl SO METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE LA English DT Article ID IMPACT DAMAGE; ALLOY C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Lerch, BA (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. EM bradley.a.lerch@grc.nasa.gov NR 18 TC 11 Z9 11 U1 1 U2 1 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 1073-5623 EI 1543-1940 J9 METALL MATER TRANS A JI Metall. Mater. Trans. A-Phys. Metall. Mater. Sci. PD DEC PY 2002 VL 33 IS 12 BP 3871 EP 3874 DI 10.1007/s11661-002-0259-2 PG 4 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 632CP UT WOS:000180206400026 ER PT J AU Grugel, RN Fedoseyev, A Kim, S AF Grugel, RN Fedoseyev, A Kim, S TI Minimizing segregation during the controlled directional solidification of dendritic alloys SO METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE LA English DT Article ID SN C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. Univ Alabama, Ctr Micrograv Res, Huntsville, AL 35899 USA. Hoseo Univ, Dept Mat Sci, Hoseo, South Korea. RP Grugel, RN (reprint author), NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. NR 24 TC 3 Z9 3 U1 0 U2 2 PU MINERALS METALS MATERIALS SOC PI WARRENDALE PA 184 THORN HILL RD, WARRENDALE, PA 15086 USA SN 1073-5623 J9 METALL MATER TRANS A JI Metall. Mater. Trans. A-Phys. Metall. Mater. Sci. PD DEC PY 2002 VL 33 IS 12 BP 3876 EP 3881 DI 10.1007/s11661-002-0261-8 PG 6 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Materials Science; Metallurgy & Metallurgical Engineering GA 632CP UT WOS:000180206400028 ER PT J AU Kelley, MS Gaffey, MJ AF Kelley, MS Gaffey, MJ TI High-albedo asteroid 434 Hungaria: Spectrum, composition and genetic connections SO METEORITICS & PLANETARY SCIENCE LA English DT Article ID AUBRITE PARENT BODY; EXPLOSIVE ERUPTIONS; MELT MIGRATION; CORE FORMATION; MINOR PLANETS; METEORITES; SEARCH; FAMILIES; DIAMOND; BODIES AB New data in the wavelength region of approximately 0.4-2.5 mum have been obtained for asteroid 434 Hungaria. This is the most complete visible to near-infrared spectrum to date for this object. The near-infrared portion of the spectrum (about 0.8-2.5 mum) is smooth, featureless, and agrees well in the overlap region with new visible region data. However, visible region (about 0.45-0.9 mum) data appear to exhibit weak, broad spectral absorption features near 0.5, 0.6-0.7, and 1 mum. If real, the presence of such features would strongly constrain the compositional determination of Hungaria since it has a relatively high albedo of 46%. Most minerals that exhibit similar absorption features, and are commonly found in meteorites, have a much lower albedo. Asteroid 434 Hungaria has been observed more than six times in these overlapping spectral regions, and it is now possible to assess its mineral composition with some confidence. The dominant phase on this asteroid is an iron-free mineral, probably enstatite. Hungaria may contain secondary phases causing subtle, visible-region absorption features. Alternatively, the surface layer(s) of the asteroid may be contaminated by an absorbing species from an external source. C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. Univ N Dakota, Dept Space Studies, Grand Forks, ND 58202 USA. RP Kelley, MS (reprint author), Georgia So Univ, Dept Geol & Geog, Statesboro, GA 30460 USA. EM mkelley@gasou.edu NR 66 TC 10 Z9 10 U1 0 U2 1 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 1086-9379 J9 METEORIT PLANET SCI JI Meteorit. Planet. Sci. PD DEC PY 2002 VL 37 IS 12 BP 1815 EP 1827 PG 13 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 633FT UT WOS:000180272400011 ER PT J AU Basu, A Wentworth, SJ McKay, DS AF Basu, A Wentworth, SJ McKay, DS TI Heterogeneous agglutinitic glass and the fusion of the finest fraction (F(3)) model SO METEORITICS & PLANETARY SCIENCE LA English DT Article ID POINT-COUNTING METHOD; DETRITAL MODES; GRAIN-SIZE; MELTING MECHANISMS; SHOCKED MIXTURES; MARE SOILS; LUNAR; REGOLITH; ORIGIN; CHEMISTRY AB Evidence in favor of the model fusion of the finest fraction (P) for the origin of lunar agglutinitic glass has been accruing. They include (1) theoretical expectations that shock pulses should engulf and melt smaller grains more efficiently than larger grains, (2) experimental results of impact shock, albeit at lower than presumed hypervelocity impacts of micrometeorites on the lunar regolith, and (3) new analyses confirming previous results that average compositions of agglutinitic glass are biased towards that of the finest fraction of lunar soils from which they had formed. We add another reason in support of the F(3) model. Finer grains of lunar soils are also much more abundant. Hence, electrostatic forces associated with the rotating terminator region bring the finest grains that are obviously much lighter than courser grains to the surface of the Moon. This further contributes to the preferential melting of the finest fraction upon micrometeoritic impacts. New backscattered electron imaging shows that agglutinitic glass is inhomogeneous at submicron scale. Composition ranges of agglutinitic glass are extreme and deviate from that of the finest fraction, even by more than an order of magnitude for some components. Additionally, we show how an ilmenite grain upon impact would produce TiO(2)-rich agglutinitic glass in complete disregard to the requirements of fusion of the finest fraction. We propose an addition to the F3 model to accommodate these observations (i.e., that micrometeorite impacts indiscriminately melt the immediate target regardless of gain size or grain composition). We, therefore, suggest that (1) agglutinitic glass is the sum of (a) the melt produced by the fusion of the finest fraction of lunar soils and (b) the microvolume of the indiscriminate target, which melts at high-shock pressures from micrometeoritic impacts, and that (2) because of the small volume of the melt and incorporating cold soil grains, the melt quenched so rapidly that it did not mix and homogenize to represent any preferential composition, for example, that of the finest fraction. C1 Indiana Univ, Dept Geol Sci, Bloomington, IN 47405 USA. Lockheed Martin, Houston, TX 77058 USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Basu, A (reprint author), Indiana Univ, Dept Geol Sci, Bloomington, IN 47405 USA. EM basu@indiana.edu NR 62 TC 9 Z9 9 U1 0 U2 0 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 1086-9379 J9 METEORIT PLANET SCI JI Meteorit. Planet. Sci. PD DEC PY 2002 VL 37 IS 12 BP 1835 EP 1842 PG 8 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 633FT UT WOS:000180272400013 ER PT J AU Safaeineili, A Gulkis, S Hofstadter, MD Jordan, RL AF Safaeineili, A Gulkis, S Hofstadter, MD Jordan, RL TI Probing the interior of asteroids and comets using radio reflection tomography SO METEORITICS & PLANETARY SCIENCE LA English DT Article ID INVERSION; RADAR; GREENLAND AB Asteroids and comets are of great scientific interest: their interior structure and composition, which are poorly known, provide information about conditions and processes that occurred during the early stages of solar system development. They are also of interest for social and economic reasons. Their proximity to Earth and abundance in the solar system make them potential sources of raw materials as well as a threat, as evidenced by past catastrophic impacts. Information on their composition and structure is therefore important to assess both the potential benefit of these objects and mitigate the potential risk they pose. This paper describes the use of radio reflection tomography for studying the interiors of asteroids and comets. We discuss technical issues regarding benefits and challenges of implementing a radio reflection tomography instrument and present potential solutions. This paper addresses a range of topics including (1) data collection scenarios, (2) data processing and inversion, and (3) instrument implementation. A "strawman" instrument capable of imaging the full interior of an asteroid or a comet with dimensions of a few kilometers is presented. Such an instrument can play a significant role in studying the near-Earth objects, both for scientific and socio-economic purposes. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Safaeineili, A (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM ali.safaeinili@jpl.nasa.gov NR 15 TC 6 Z9 6 U1 2 U2 3 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 1086-9379 J9 METEORIT PLANET SCI JI Meteorit. Planet. Sci. PD DEC PY 2002 VL 37 IS 12 BP 1953 EP 1963 PG 11 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 633FT UT WOS:000180272400022 ER PT J AU Treiman, AH Lindstrom, DJ Schwandt, CS Franchi, IA Morgan, ML AF Treiman, AH Lindstrom, DJ Schwandt, CS Franchi, IA Morgan, ML TI A "mesosiderite" rock from northern Siberia, Russia: Not a meteorite SO METEORITICS & PLANETARY SCIENCE LA English DT Article ID OXYGEN-ISOTOPE; FLOOD BASALTS; TRAPS; ACHONDRITES; ORIGIN; MAGMA AB A possible mesosiderite meteorite was found in the area of the Putorana Plateau, Noril'sk district, Siberia, Russia. Although this rock resembles a mesosiderite in its hand-sample aspect and in having Ni-bearing iron metal, it is not a meteorite. This inference is based on the lack of a fusion crust, the lack of cosmogenic nuclides, oxygen with terrestrial isotope ratios, and several mineral chemical criteria. Most likely, the rock is from the iron-metal-bearing basalts of the Siberian Trap basalt sequence, which are mined for their base and platinum-group metals. Mesosiderite imposters like this may be recognized by (1) the presence of Cu metal in hand sample or as microscopic blebs in the low-Ni metal (kamacite), (2) the absence of high-Ni metal (taenite), and (3) the presence of iron carbide (cohenite) enclosing the kamacite. Even if these macroscopic tests are inconclusive, isotopic and mineral chemical tests will also distinguish rocks like this from mesosiderites. C1 Lunar & Planetary Inst, Houston, TX 77058 USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. Lockheed Martin, Houston, TX 77058 USA. Open Univ, Planetary & Space Sci Res Inst, Milton Keynes MK7 6AA, Bucks, England. Mile High Meteorites, Lakewood, CO 80215 USA. RP Treiman, AH (reprint author), Lunar & Planetary Inst, 3600 Bay Area Blvd, Houston, TX 77058 USA. NR 42 TC 6 Z9 6 U1 0 U2 4 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 USA SN 1086-9379 J9 METEORIT PLANET SCI JI Meteorit. Planet. Sci. PD DEC PY 2002 VL 37 IS 12 SU S BP B13 EP B22 PG 10 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 634JY UT WOS:000180337300003 ER PT J AU Canuto, VM AF Canuto, VM TI Diffusion in stars: the case of gravity waves, rigid rotation and stable stratification SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE turbulence; stars : abundances; stars : interiors ID ANGULAR-MOMENTUM TRANSPORT; DIFFERENTIAL ROTATION; TURBULENCE; LITHIUM; MODEL; DIP AB We study mixing in the tachocline in the presence of a source (gravity waves of power Pi) and two sinks (rigid rotation Omega and stable stratification of strength del(ad) - del > 0). The Reynolds stresses R-ij are found to be proportional to PiOmega(-1)r(ij), where the dimensionless tensor r(ij) may increase, decrease or saturate with Omega depending on the component (i j). The heat fluxes are found to be proportional to Pih(i), where the dimensionless h(r,theta) first decrease with Omega and then saturate while h(theta) always decreases with Omega. Numerical values of the momentum and heat diffusivities are derived and discussed. Future studies will include differential rotation, the mu-barrier and meridional currents. C1 NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Columbia Univ, Dept Appl Math & Phys, New York, NY 10027 USA. RP Canuto, VM (reprint author), NASA, Goddard Inst Space Studies, 2880 Broadway, New York, NY 10025 USA. NR 17 TC 5 Z9 5 U1 0 U2 0 PU BLACKWELL PUBLISHING LTD PI OXFORD PA 9600 GARSINGTON RD, OXFORD OX4 2DG, OXON, ENGLAND SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD DEC PY 2002 VL 337 IS 2 BP 713 EP 719 DI 10.1046/j.1365-8711.2002.05962.x PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 619TT UT WOS:000179494100031 ER PT J AU Keppenne, CL Rienecker, MM AF Keppenne, CL Rienecker, MM TI Initial testing of a massively parallel ensemble Kalman filter with the Poseidon isopycnal ocean general circulation model SO MONTHLY WEATHER REVIEW LA English DT Article ID QUASI-GEOSTROPHIC MODEL; TROPICAL PACIFIC-OCEAN; DATA ASSIMILATION; EL-NINO; ANALYSIS SCHEME; INTERPOLATION; OCEANOGRAPHY; PREDICTION AB A multivariate ensemble Kalman filter (MvEnKF) implemented on a massively parallel computer architecture has been developed for the Poseidon ocean circulation model and tested with a Pacific basin model configuration. There are about 2 million prognostic state-vector variables. Parallelism for the data assimilation step is achieved by regionalization of the background-error covariances that are calculated from the phase - space distribution of the ensemble. Each processing element ( PE) collects elements of a matrix measurement functional from nearby PEs. To avoid the introduction of spurious long-range covariances associated with finite ensemble sizes, the background-error covariances are given compact support by means of a Hadamard ( element by element) product with a three-dimensional canonical correlation function. The methodology and the MvEnKF implementation are discussed. To verify the proper functioning of the algorithms, results from an initial experiment with in situ temperature data are presented. Furthermore, it is shown that the regionalization of the background covariances has a negligible impact on the quality of the analyses. Even though the parallel algorithm is very efficient for large numbers of observations, individual PE memory, rather than speed, dictates how large an ensemble can be used in practice on a platform with distributed memory. C1 NASA, Seasonal Interannual Predict Project, Lab Hydrospher Proc, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Sci Applicat Int Corp, Beltsville, MD USA. RP Keppenne, CL (reprint author), NASA, Seasonal Interannual Predict Project, Lab Hydrospher Proc, Goddard Space Flight Ctr, Mail Code 971, Greenbelt, MD 20771 USA. EM clk@janus.gsfc.nasa.gov NR 42 TC 92 Z9 92 U1 1 U2 7 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 DEC PY 2002 VL 130 IS 12 BP 2951 EP 2965 DI 10.1175/1520-0493(2002)130<2951:ITOAMP>2.0.CO;2 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 615WD UT WOS:000179269500009 ER PT J AU Karyampudi, VM Pierce, HF AF Karyampudi, VM Pierce, HF TI Synoptic-scale influence of the Saharan air layer on tropical cyclogenesis over the eastern Atlantic SO MONTHLY WEATHER REVIEW LA English DT Article ID AFRICAN WAVE DISTURBANCES; CYCLONE FORMATION; HURRICANE SEASON; OBSERVATIONAL ANALYSIS; NORTH-ATLANTIC; PHASE III; PACIFIC; GENESIS; MONSOON; STORM AB The formations of Hurricane Andrew, Tropical Storm Ernesto, and Hurricane Luis, which occurred, respectively, during the 1992, 1994, and 1995 hurricane seasons over the eastern Atlantic, have been investigated by utilizing the European Centre for Medium-Range Weather Forecasts ( ECMWF) gridded data analyses. These cases were selected to illustrate the contrasting influences of the Saharan air layer ( SAL) on tropical cyclogenesis. Analyses results show that Tropical Storm Ernesto ( 1994) and Hurricane Luis ( 1995) formed from the merger of the low-level ( 925 hPa) and midlevel ( 700 hPa) vortices over the eastern Atlantic within the monsoon trough enhanced by surges in the trades. Midlevel vortices associated with each case appear to evolve from African wave troughs enhanced by cyclonic shear vorticity of the midtropospheric jet, which existed to the south of an SAL anticyclonic eddy as an elongated wind maximum. Vorticity budget calculations suggest that vortex stretching dominated the enhancement of low-level vortices, whereas positive vorticity advection (PVA) on the south and leading edge of the midlevel easterly jet ( MLEJ) but ahead of the trough axis contributed to the enhancement of midlevel vortices for both cases. Persistent upper-level divergence associated with an anticyclonic circulation appears to have aided in the formation of Ernesto, whereas for Luis, no such prior forcing is evident. Hurricane Andrew ( 1992), on the other hand, appears to form from a deep African wave vortex. Vortex stretching contributed to the development of low-level vortices. Although cyclonic shear vorticity to the south of the MLEJ is present in association with a deeper and wider SAL devoid of its characteristic anticyclonic eddy ( unlike in Ernesto and Luis), the midlevel contribution from PVA on the south side of the jet to the maintenance of the midlevel vortex is found to be insignificant in Andrew due to negligible cross-(vorticity) contour flow to the south and ahead of the wave trough. However, the pre-Andrew growth was dominated by PVA at upper levels associated with easterly wave perturbations to the south of an anticyclonic circulation center but to the north of an upper-level easterly jet. In at least two cases (i.e., Ernesto and Luis), the SAL directly contributed to the negative PV anomalies to the north of the MLEJ, which resulted in the sign reversal of the meridional gradient of potential vorticity ( between 850- and 700-hPa levels), which satisfies the Charney and Stern criterion for barotropic and baroclinic instability across the midtropospheric jet over the eastern Atlantic. The baroclinic mechanism, proposed by Karyampudi and Carlson, is found to be valid in explaining some of the wave growth processes involved in the genesis of the same two cases. Based on these results, it is concluded that SAL had a positive influence on at least two cases [ both ( Ernesto and Luis) occurred in normal Sahel rainfall years], in contrast to a negative influence on Andrew, which occurred in an extremely dry year. C1 Univ Maryland, Dept Meteorol, College Pk, MD 20742 USA. NASA, Atmospheres Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Karyampudi, VM (reprint author), NOAA, SAIC, NCEP, 5200 Auth Rd, Camp Springs, MD 20746 USA. EM Mohan.Karyampudi@noaa.gov NR 58 TC 65 Z9 65 U1 3 U2 9 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 DEC PY 2002 VL 130 IS 12 BP 3100 EP 3128 DI 10.1175/1520-0493(2002)130<3100:SSIOTS>2.0.CO;2 PG 29 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 615WD UT WOS:000179269500019 ER PT J AU McMillan, RA Paavola, CD Howard, J Chan, SL Zaluzec, NJ Trent, JD AF McMillan, RA Paavola, CD Howard, J Chan, SL Zaluzec, NJ Trent, JD TI Ordered nanoparticle arrays formed on engineered chaperonin protein templates SO NATURE MATERIALS LA English DT Article ID SINGLE-ELECTRON TRANSISTOR; SULFOLOBUS-SHIBATAE; QUANTUM DOTS; MOLECULAR LITHOGRAPHY; ARCHAEAL CHAPERONIN; CRYSTAL-STRUCTURE; VIRUS-PARTICLES; DNA; NANOCRYSTALS; DEVICES AB Traditional methods for fabricating nanoscale arrays are usually based on lithographic techniques. Alternative new approaches rely on the use of nanoscale templates made of synthetic or biological materials. Some proteins, for example, have been used to form ordered two-dimensional arrays. Here, we fabricated nanoscale ordered arrays of metal and semiconductor quantum dots by binding preformed nanoparticles onto crystalline protein templates made from genetically engineered hollow double-ring structures called chaperonins. Using structural information as a guide, a thermostable recombinant chaperonin subunit was modified to assemble into chaperonins with either 3 nm or 9 nm apical pores surrounded by chemically reactive thiols. These engineered chaperonins were crystallized into two-dimensional templates up to 20 mum in diameter. The peiriodic solvent-exposed thiols within these crystalline templates were used to size-selectively bind and organize either gold (1.4, 5 or 10 nm) or CdSe-ZnS semiconductor (4.5 nm) quantum dots into arrays. The order within the arrays was defined by the lattice of the undedying protein crystal. By combining the self-assembling properties of chaperonins with mutations guided by structural modelling, we demonstrate that quantum dots can be manipulated using modified chaperonins and organized into arrays for use in next-generation electronic and photonic devices. C1 NASA, Ames Res Ctr, Ctr Nanotechnol, Moffett Field, CA 94035 USA. NASA, Ames Res Ctr, Astrobiol Technol Branch, Moffett Field, CA 94035 USA. SETI Inst, Mountain View, CA 94043 USA. Argonne Natl Lab, Div Mat Sci, Argonne, IL 60439 USA. RP McMillan, RA (reprint author), NASA, Ames Res Ctr, Ctr Nanotechnol, Mail Stop 239-15, Moffett Field, CA 94035 USA. NR 43 TC 259 Z9 260 U1 6 U2 82 PU NATURE PUBLISHING GROUP PI LONDON PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 1476-1122 J9 NAT MATER JI Nat. Mater. PD DEC PY 2002 VL 1 IS 4 BP 247 EP 252 DI 10.1038/nmat775 PG 6 WC Chemistry, Physical; Materials Science, Multidisciplinary; Physics, Applied; Physics, Condensed Matter SC Chemistry; Materials Science; Physics GA 654LR UT WOS:000181498800023 PM 12618787 ER PT J AU Moles, A Scott, R AF Moles, A Scott, R TI Growth and behavior of juvenile Alaskan flatfishes in the laboratory SO NORTHWEST SCIENCE LA English DT Article ID PLEURONECTES-PLATESSA; PACIFIC HALIBUT; TEMPERATURE; RETENTION; PLAICE; SALMON; FISH; SEA AB Juvenile Pacific halibut reared in the laboratory grew at a faster rate and had a more uniform distribution in behavior tests than juveniles of yellowfin sole and rock sole. Juvenile yellowfin sole and rock sole had similar 90-d growth rates (0.71-0.83% BWD) in the laboratory at 10degreesC, whereas Pacific halibut grew significantly faster (1.29% BWD). Rock sole grew the same on both mud and sand, despite a known preference for sand substrate in the field. Yellowfin sole and rock sole had an aggregated distribution in the tanks as measured by nearest-neighbor analysis regardless of the presence of other species, whereas Pacific halibut had a uniform distribution. These are the first observations of growth and behavior of juveniles of these species in the laboratory. C1 NOAA, Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr, Auke Bay Lab, Juneau, AK 99801 USA. RP Moles, A (reprint author), NOAA, Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr, Auke Bay Lab, 11305 Glacier Highway, Juneau, AK 99801 USA. NR 22 TC 6 Z9 6 U1 1 U2 1 PU WASHINGTON STATE UNIV PI PULLMAN PA PO BOX 645020, PULLMAN, WA 99164-5910 USA SN 0029-344X J9 NORTHWEST SCI JI Northwest Sci. PD WIN PY 2002 VL 76 IS 1 BP 41 EP 45 PG 5 WC Ecology SC Environmental Sciences & Ecology GA 533WX UT WOS:000174554200005 ER PT J AU Anderhub, H Bates, JR Batzner, D Baumgartner, S Biland, A Camps, C Capell, M Commichau, V Djambazov, L Fanchiang, YJ Flugge, G Fritschi, M Grimm, O Hangarter, K Hofer, H Horisberger, U Kan, R Kastli, W Kenney, GP Kim, GN Kim, KS Koutsenko, V Kraber, M Kuipers, J Lebedev, A Lee, MW Lee, SC Lewis, R Lustermann, W Pauss, F Rauber, T Ren, D Ren, ZL Roser, U Son, D Ting, SCC Tiwari, AN Viertel, GM von Gunten, H Wicki, SW Wang, TS Yang, J Zimmermann, B AF Anderhub, H Bates, JR Batzner, D Baumgartner, S Biland, A Camps, C Capell, M Commichau, V Djambazov, L Fanchiang, YJ Flugge, G Fritschi, M Grimm, O Hangarter, K Hofer, H Horisberger, U Kan, R Kastli, W Kenney, GP Kim, GN Kim, KS Koutsenko, V Kraber, M Kuipers, J Lebedev, A Lee, MW Lee, SC Lewis, R Lustermann, W Pauss, F Rauber, T Ren, D Ren, ZL Roser, U Son, D Ting, SCC Tiwari, AN Viertel, GM von Gunten, H Wicki, SW Wang, TS Yang, J Zimmermann, B TI Preliminary results from the Prototype Synchrotron Radiation Detector on Space Shuttle mission STS-108 SO NUCLEAR PHYSICS B-PROCEEDINGS SUPPLEMENTS LA English DT Article; Proceedings Paper CT 1st International Conference on Particle and Fundamental Physics in Space CY MAY 14-19, 2002 CL ISOLA ELBA, ITALY SP Inst Nazl Fis Nucl, Agenzia Spaziale Italiana ID ELECTRONS AB A Synchrotron Radiation Detector measures synchrotron radiation emitted by high energetic particles in the earth magnetic field. This allows to identify cosmic ray electrons and positrons with energies in the TeV region. One possibility for such a detector outside the atmosphere uses YAP crystals to measure synchrotron photons with energies in the keV range. As such a detector can not distinguish between photons and electrons, the main problems are the diffuse cosmic ray gamma background and low energetic electrons in the vicinity of the earth. While the intensity of the diffuse gamma rays is known quite well, there exists limited knowledge about keV-electrons in low earth orbits. To measure these electrons a Prototype Synchrotron Radiation Detector (PSRD) was flown with Space Shuttle mission STS-108 (Dec.2001) and preliminary analysis of the data show very favorable results. C1 Swiss Fed Inst Technol, Labor Hochenergiephys, Zurich, Switzerland. NASA, Johnson Space Ctr, Houston, TX USA. Swiss Fed Inst Technol, Labor Festkorperphys, Zurich, Switzerland. Rhein Westfal TH Aachen, Phys Inst 3 B, Aachen, Germany. MIT, Nucl Sci Lab, Cambridge, MA USA. CSIST, Lungtan 32500, Taiwan. Kyungpook Natl Univ, Ctr High Engergy Phys, Taegu, South Korea. Acad Sinica, Inst Phys, Taipei, Taiwan. Goddard Space Flight Ctr, Greenbelt, MD USA. RP Biland, A (reprint author), Swiss Fed Inst Technol, Labor Hochenergiephys, Zurich, Switzerland. NR 12 TC 2 Z9 2 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0920-5632 J9 NUCL PHYS B-PROC SUP JI Nucl. Phys. B-Proc. Suppl. PD DEC PY 2002 VL 113 BP 166 EP 169 AR PII S0920-5632(02)01837-6 DI 10.1016/S0920-5632(02)01837-6 PG 4 WC Physics, Particles & Fields SC Physics GA 626ZY UT WOS:000179904700023 ER PT J AU Sasaki, M Matsumoto, H Nozaki, M Saeki, T Abe, K Anraku, K Asaoka, Y Fujikawa, M Fuke, H Imori, M Haino, S Izumi, K Maeno, T Makida, Y Matsuda, S Matsui, N Matsukawa, T Matsunaga, H Mitchell, JW Mitsui, T Moiseev, A Motoki, M Nishimura, J Orito, S Ormes, JF Sanuki, T Shikaze, Y Seo, ES Sonoda, T Streitmatter, R Suzuki, J Tanaka, K Tanizaki, K Ueda, I Wang, JZ Yajima, Y Yamagami, Y Yamamoto, A Yamamoto, Y Yamato, K Yoshida, T Yoshimura, K AF Sasaki, M Matsumoto, H Nozaki, M Saeki, T Abe, K Anraku, K Asaoka, Y Fujikawa, M Fuke, H Imori, M Haino, S Izumi, K Maeno, T Makida, Y Matsuda, S Matsui, N Matsukawa, T Matsunaga, H Mitchell, JW Mitsui, T Moiseev, A Motoki, M Nishimura, J Orito, S Ormes, JF Sanuki, T Shikaze, Y Seo, ES Sonoda, T Streitmatter, R Suzuki, J Tanaka, K Tanizaki, K Ueda, I Wang, JZ Yajima, Y Yamagami, Y Yamamoto, A Yamamoto, Y Yamato, K Yoshida, T Yoshimura, K TI Progress in search for antihelium with BESS SO NUCLEAR PHYSICS B-PROCEEDINGS SUPPLEMENTS LA English DT Article; Proceedings Paper CT 1st International Conference on Particle and Fundamental Physics in Space CY MAY 14-19, 2002 CL ISOLA ELBA, ITALY SP Inst Nazl Fis Nucl, Agenzia Spaziale Italiana ID ONBOARD BESS; COSMIC-RAYS; SPECTROMETER; HELIUM; FLUX AB We have searched for antihelium nuclei in cosmic rays using the data obtained from balloon flights of the BESS magnetic spectrometer. The search was mainly based on track-quality selection, followed by rigidity analysis, and on the time-of-flight and dE/dx measurements by the scintillation counter hodoscope. We analysed all the data collected during 1993-2000 with a common analysis procedure. No antihelium nuclei events were found in the energy range from I to 14 GV. In order to determine a new upper limit, we have simulated the loss in the air and in the instrument of He (He) using the GEANT/GHEISHA code. Combined with the data collected in 1993 through 2000, a new 95 % confidence upper limit for the ratio of He/He at the top of the atmosphere of 6.8 x 10(-7) has been obtained to be after correcting for the interactions in the air and in the instruments. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Tokyo, Tokyo 1130033, Japan. Kobe Univ, Kobe, Hyogo 6578501, Japan. KEK, High Energy Accelerator Res Org, Tsukuba, Ibaraki 3050801, Japan. Univ Maryland, College Pk, MD 20742 USA. ISAS, Kanagawa 2298510, Japan. RP Sasaki, M (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RI MOTOKI, Masakazu/B-4212-2009; OI Seo, Eun-Suk/0000-0001-8682-805X NR 16 TC 19 Z9 19 U1 1 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0920-5632 J9 NUCL PHYS B-PROC SUP JI Nucl. Phys. B-Proc. Suppl. PD DEC PY 2002 VL 113 BP 202 EP 207 AR PII S0920-5632(02)01842-X DI 10.1016/S0920-5632(02)01842-X PG 6 WC Physics, Particles & Fields SC Physics GA 626ZY UT WOS:000179904700028 ER PT J AU Yamamoto, A Mitchell, J Abe, K Fuke, H Haino, S Ikeda, N Izumi, K Lee, M Maeno, T Makida, Y Matsuda, S Matsui, N Matsumoto, H Moiseev, A Nishimura, J Nozaki, M Omiya, H Ormes, JF Sasaki, M Seo, ES Shikaze, Y Suzuki, J Tanaka, K Tanizaki, K Yamagami, T Yamamoto, Y Yamato, K Yoshida, T Yoshimura, K AF Yamamoto, A Mitchell, J Abe, K Fuke, H Haino, S Ikeda, N Izumi, K Lee, M Maeno, T Makida, Y Matsuda, S Matsui, N Matsumoto, H Moiseev, A Nishimura, J Nozaki, M Omiya, H Ormes, JF Sasaki, M Seo, ES Shikaze, Y Suzuki, J Tanaka, K Tanizaki, K Yamagami, T Yamamoto, Y Yamato, K Yoshida, T Yoshimura, K TI BESS-Polar: Long duration flights at Antarctica to search for primordial antiparticles SO NUCLEAR PHYSICS B-PROCEEDINGS SUPPLEMENTS LA English DT Article; Proceedings Paper CT 1st International Conference on Particle and Fundamental Physics in Space CY MAY 14-19, 2002 CL ISOLA ELBA, ITALY SP Inst Nazl Fis Nucl, Agenzia Spaziale Italiana ID COSMIC-RAY ANTIPROTONS; SOLAR MINIMUM; FLUX; ANTIHELIUM; SPECTRUM; LIMIT AB The BESS-Polar experiment with long-duration balloon flights at Antarctica aims at extremely sensitive measurement of low energy antiprotons to search for novel primary origins in the early Universe, and to study cosmic-ray propagation and solar modulation. The search for cosmic antimatter is a fundamental objective to study baryon asymmetry in the Universe. The BESS experiment with high rigidity resolution and large geometrical acceptance will maximize advantages of long duration flights at Antarctica where the rigidity cut-off is lowest. A very compact and thin superconducting magnet spectrometer is being developed to maximize the detector performance in low energies. The BESS-Polar project and progress of the development are described. C1 KEK, High Energy Accelerator Res Org, Tsukuba, Ibaraki 3050801, Japan. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Tokyo, Tokyo 1130033, Japan. Kobe Univ, Kobe, Hyogo 6578501, Japan. Univ Maryland, College Pk, MD 20742 USA. ISAS, Sagamihara, Kanagawa 2298510, Japan. RP Yamamoto, A (reprint author), KEK, High Energy Accelerator Res Org, Tsukuba, Ibaraki 3050801, Japan. OI Seo, Eun-Suk/0000-0001-8682-805X NR 26 TC 5 Z9 5 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0920-5632 J9 NUCL PHYS B-PROC SUP JI Nucl. Phys. B-Proc. Suppl. PD DEC PY 2002 VL 113 BP 208 EP 212 AR PII S0920-5632(02)01843-1 DI 10.1016/S0920-5632(02)01843-1 PG 5 WC Physics, Particles & Fields SC Physics GA 626ZY UT WOS:000179904700029 ER PT J AU Vasilkov, AP Herman, J Krotkov, NA Kahru, M Mitchell, BG Hsu, C AF Vasilkov, AP Herman, J Krotkov, NA Kahru, M Mitchell, BG Hsu, C TI Problems in assessment of the ultraviolet penetration into natural waters from space-based measurements SO OPTICAL ENGINEERING LA English DT Article; Proceedings Paper CT Conference on Advances in UV Ground- and Space-Based Measurements and Modeling CY JUL, 2001 CL SAN DIEGO, CA DE UV irradiance; radiative transfer models; seawater optical properties ID DISSOLVED ORGANIC-MATTER; SURFACE UV IRRADIANCE; ABSORPTION-SPECTRUM; SATELLITE ESTIMATION; CALIFORNIA CURRENT; OPTICAL-PROPERTIES; YELLOW SUBSTANCE; EARTHS SURFACE; LIQUID WATER; OCEAN WATER AB Satellite instruments currently provide global maps of surface UV irradiance by combining backscattered radiance data with radiative transfer models. The models are often limited by uncertainties in physical input parameters of the atmosphere and surface. Global mapping of the underwater UV irradiance creates further challenges for the models. The uncertainties in physical input parameters become more serious because of the presence of absorbing and scattering quantities caused by biological processes within the oceans. We summarize the problems encountered in the assessment of the underwater UV irradiance from space-based measurements, and propose approaches to resolve the problems. We have developed a radiative transfer scheme for computation of the UV irradiance in the atmosphere-ocean system. The scheme makes use of input parameters derived from satellite instruments such as the total ozone mapping spectrometer (TOMS) and sea-viewing wide field-of-view sensor (SeaWiFS). The major problem in assessment of the surface UV irradiance is to accurately quantify the effects of clouds. Unlike the standard TOMS UV algorithm, we use the cloud fraction products available from SeaWiFS and MODIS to calculate instantaneous surface flux at the ocean surface. Daily UV doses can be calculated by assuming a model of constant cloudiness throughout the day. Both SeaWiFS and a moderate resolution imaging spectroradiometer (MODIS) provide some estimates of seawater optical properties in the visible. To calculate the underwater UV flux, the seawater optical properties must be extrapolated down to shorter wavelengths. Currently, the problem of accurate extrapolation of visible data down to the UV spectral range is not solved completely, and there are few available measurements. The major difficulty is insufficient correlation between photosynthetic and photoprotective pigments of phytoplankton absorbing in the visible and UV, respectively. We propose to empirically parameterize seawater absorption in the UV on a basis of available datasets of bio-optical measurements from a variety of ocean waters. Another problem is the lack of reliable data on pure seawater absorption in the UV. Laboratory measurements of the UV absorption of both pure water and pure seawater are required. (C) 2002 Society of Photo-Optical Instrumentation Engineers. C1 Sci Syst & Applicat Inc, Lanham, MD USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Maryland Baltimore Cty, Goddard Earth Sci & Technol Ctr, NASA, Greenbelt, MD 20771 USA. Univ Calif San Diego, Scripps Inst Oceanog, La Jolla, CA 92093 USA. RP Sci Syst & Applicat Inc, 10210 Greenbelt Rd, Lanham, MD USA. EM alexander_vassilkov@sesda.com RI Hsu, N. Christina/H-3420-2013; Krotkov, Nickolay/E-1541-2012; OI Krotkov, Nickolay/0000-0001-6170-6750; Herman, Jay/0000-0002-9146-1632 NR 53 TC 13 Z9 13 U1 0 U2 0 PU SPIE-SOC PHOTO-OPTICAL INSTRUMENTATION ENGINEERS PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98225 USA SN 0091-3286 EI 1560-2303 J9 OPT ENG JI Opt. Eng. PD DEC PY 2002 VL 41 IS 12 BP 3019 EP 3027 DI 10.1117/1.1516822 PG 9 WC Optics SC Optics GA 627UL UT WOS:000179954500007 ER PT J AU Krotkov, N Herman, J Bhartia, PK Seftor, C Arola, A Kaurola, J Kalliskota, S Taalas, P Geogdzhaev, IV AF Krotkov, N Herman, J Bhartia, PK Seftor, C Arola, A Kaurola, J Kalliskota, S Taalas, P Geogdzhaev, IV TI Version 2 total ozone mapping spectrometer ultraviolet algorithm: problems and enhancements SO OPTICAL ENGINEERING LA English DT Article; Proceedings Paper CT Conference on Advances in UV Ground- and Space-Based Measurements and Modeling CY JUL, 2001 CL SAN DIEGO, CALIFORNIA DE UV irradiance; TOMS; radiative transfer models; aerosols; clouds; snow albedo ID AEROSOL OPTICAL DEPTH; SURFACE UV IRRADIANCE; SATELLITE ESTIMATION; EARTHS SURFACE; ATMOSPHERIC TRANSMISSION; DATA PRODUCTS; TOMS DATA; NIMBUS 7; SOLAR UV; RADIATION AB Satellite instruments provide global maps of surface UV irradiance by combining backscattered radiance measurements with radiative transfer models. The accuracy of the models is limited by uncertainties in input parameters representing the atmosphere and the Earth's surface. To reduce these uncertainties, we have made enhancements to the currently operational TOMS surface UV irradiance algorithm (Version 1) by including the effects of diurnal variations of cloudiness, an improved treatment of snow/ice, and a preliminary aerosol correction. We compare results of the version 1 TOMS UV algorithm and the proposed version. We evaluate different approaches for improved treatment for average cloud attenuation within a satellite pixel, with and without snow/ ice on the ground. In addition to treating cloud transmission based only on the measurements at the local time of the TOMS observations, the results from other satellites and weather assimilation models can be used to estimate atmospheric UV irradiance transmission throughout the day. A new method is proposed to obtain a more realistic treatment of the effects from snow-covered terrain. The method is based on an empirical relation between UV reflectivity and measured snow depth. The new method reduces the bias between the TOMS UV estimations and ground-based UV measurements for snow periods. We also briefly discuss the complex problem of estimating surface UV radiation in presence of UV-absorbing aerosols. The improved (Version 2) algorithm can be applied to reprocess the existing TOMS UV irradiance and exposure estimates (since November 1978) and to future satellite sensors (e.g., GOME-2, OMI on EOS/Aura, and Triana/EPIC). (C) 2002 Society of Photo-Optical Instrumentation Engineers. C1 Univ Maryland Baltimore Cty, Goddard Earth Sci & Technol Ctr, Baltimore, MD 21250 USA. NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. Raytheon ITSS, Lanham, MD 20706 USA. Finnish Meteorol Inst, FIN-00101 Helsinki, Finland. Columbia Univ, New York, NY 10027 USA. NASA, Goddard Inst Space Studies, New York, NY 10027 USA. RP Krotkov, N (reprint author), Univ Maryland Baltimore Cty, Goddard Earth Sci & Technol Ctr, Baltimore, MD 21250 USA. RI Krotkov, Nickolay/E-1541-2012; Bhartia, Pawan/A-4209-2016; OI Krotkov, Nickolay/0000-0001-6170-6750; Bhartia, Pawan/0000-0001-8307-9137; Herman, Jay/0000-0002-9146-1632; Arola, Antti/0000-0002-9220-0194 NR 79 TC 31 Z9 31 U1 0 U2 3 PU SPIE-INT SOCIETY OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98225 USA SN 0091-3286 J9 OPT ENG JI Opt. Eng. PD DEC PY 2002 VL 41 IS 12 BP 3028 EP 3039 DI 10.1117/1.1519541 PG 12 WC Optics SC Optics GA 627UL UT WOS:000179954500008 ER PT J AU Fioletov, VE Kerr, JB Wardle, DI Krotkov, N Herman, JR AF Fioletov, VE Kerr, JB Wardle, DI Krotkov, N Herman, JR TI Comparison of Brewer ultraviolet irradiance measurements with total ozone mapping spectrometer satellite retrievals SO OPTICAL ENGINEERING LA English DT Article; Proceedings Paper CT Conference on Advances in UV Ground- and Space-Based Measurements and Modeling CY JUL, 2001 CL SAN DIEGO, CALIFORNIA DE UV irradiance; Brewer; total ozone mapping spectrometer; cloud amount ID SURFACE UV IRRADIANCE; SOLAR UV; TOMS; RADIATION; REFLECTIVITY; CLIMATOLOGY; CLOUDS; ERROR AB Comparison of measured UV irradiance with estimates from satellite observation is potentially effective for the validation of data from the two sources. Summer data from ten Canadian Brewer sites were compared in this study with noon UV irradiance estimated from total ozone mapping spectrometer (TOMS) measurements. In general, TOMS estimates can successfully reproduce long-term and major short-term UV variations. However, there are some systematic differences between the measurements at the ground and satellite-retrieved UV irradiance. From 3 to 11% of the Brewer-TOMS difference can be attributed to the Brewer angular response error. This error depends on the solar zenith angle and cloud conditions, and is different from instrument to instrument. When the angular response of the Brewer instrument is considered and applied, the Brewer data are still lower than TOMS-estimated UV irradiance by 9 to 10% on average at all sites except one. The difference is close to zero at one station (Saturna Island), possibly due to its much cleaner air. The bias can be seen in clear sky conditions and at the 324-nm wavelength, i.e., it is not related to local cloud conditions or absorption by ozone or SO2. (C) 2002 Society of Photo-Optical Instrumentation Engineers. C1 Meteorol Serv Canada, Toronto, ON, Canada. Univ Maryland Baltimore Cty, Goddard Earth Sci & Technol Ctr, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Fioletov, VE (reprint author), Meteorol Serv Canada, Toronto, ON, Canada. RI Krotkov, Nickolay/E-1541-2012; OI Krotkov, Nickolay/0000-0001-6170-6750; Herman, Jay/0000-0002-9146-1632; Fioletov, Vitali/0000-0002-2731-5956 NR 26 TC 61 Z9 61 U1 0 U2 2 PU SPIE-INT SOCIETY OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98225 USA SN 0091-3286 J9 OPT ENG JI Opt. Eng. PD DEC PY 2002 VL 41 IS 12 BP 3051 EP 3061 DI 10.1117/1.1516818 PG 11 WC Optics SC Optics GA 627UL UT WOS:000179954500010 ER PT J AU Chubarova, NY Yurova, AY Krotkov, N Herman, J Bhartia, PK AF Chubarova, NY Yurova, AY Krotkov, N Herman, J Bhartia, PK TI Comparisons between ground measurements of broadband ultraviolet irradiance (300 to 380 nm) and total ozone mapping spectrometer ultraviolet estimates at Moscow from 1979 to 2000 SO OPTICAL ENGINEERING LA English DT Article; Proceedings Paper CT Conference on Advances in UV Ground- and Space-Based Measurements and Modeling CY JUL, 2001 CL SAN DIEGO, CALIFORNIA DE surface UV irradiance; TOMS UV retrievals; aerosol; cloud attenuation; spatial and local surface snow albedo ID SURFACE UV IRRADIANCE; SATELLITE ESTIMATION; REFLECTIVITY; RADIATION; AEROSOLS; NORTHERN; CLOUDS; SNOW; SKY AB We show the comparisons between ground-based measurements of spectrally integrated (300 to 380 nm) UV irradiance and satellite estimates from the total ozone mapping spectrometer (TOMS) total ozone and reflectivity data for the whole period of TOMS measurements (1979 to 2000) over the Meteorological Observatory of Moscow State University (MO MSU), Russia. Several aspects of the comparisons are analyzed, including effects of cloudiness, aerosol, and snow cover. Special emphasis is given to the effect of different spatial and temporal averaging of ground-based data when comparing low-resolution satellite measurements. The comparisons in cloud-free conditions with different aerosol loading have revealed positive TOMS bias with interannual variations within +5 to +20%. Reprocessing the TOMS data by accounting for boundary layer aerosol absorption (single scattering albedo similar to0.9) removes the bias for all-sky conditions, except for completely overcast situations, where the TOMS bias remains large (15 to 17%). The single scattering albedo was independently verified using sun photometer (CIMEL Electronique) sun and sky-radiance measurements at MO MSU in September 2001. The analysis of interannual UV variations shows quite similar behavior for both TOMS and ground measurements (correlation coefficient r approximate to 0.8). No long-term trend in the annual mean bias was found for all conditions. Both TOMS and ground data show positive trends in broadband UV irradiance (300 to 380 nm) between 1979 and 2000. The UV trend is attributed to decreases in both cloudiness and aerosol optical thickness during the late 1990s over the Moscow region. However, if the analyzed period is extended to include the preTOMS era (1968 to 2000 period), no trend in ground UV irradiance is detected. (C) 2002 Society of Photo-Optical Instrumentation Engineers. C1 Moscow MV Lomonosov State Univ, Dept Geog, Meteorol Observ, Moscow 119899, Russia. Univ Maryland Baltimore Cty, Goddard Earth Sci & Technol Ctr, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. RP Chubarova, NY (reprint author), Moscow MV Lomonosov State Univ, Dept Geog, Meteorol Observ, Moscow 119899, Russia. RI Krotkov, Nickolay/E-1541-2012; Bhartia, Pawan/A-4209-2016; OI Krotkov, Nickolay/0000-0001-6170-6750; Bhartia, Pawan/0000-0001-8307-9137; Herman, Jay/0000-0002-9146-1632 NR 23 TC 23 Z9 25 U1 1 U2 1 PU SPIE-INT SOCIETY OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98225 USA SN 0091-3286 J9 OPT ENG JI Opt. Eng. PD DEC PY 2002 VL 41 IS 12 BP 3070 EP 3081 DI 10.1117/1.1516819 PG 12 WC Optics SC Optics GA 627UL UT WOS:000179954500012 ER PT J AU Bhatia, AK AF Bhatia, AK TI Electron-He+ elastic scattering SO PHYSICAL REVIEW A LA English DT Article AB In a previous paper [Bhatia and Temkin, Phys. Rev. A 64, 032709-1 (2001)], electron-hydrogen S-wave scattering phase shifts were calculated using the optical potential approach. This method is bow extended to the singlet and triplet electron-He+ scattering in the elastic region. Phase shifts are calculated using Hylleraas-type correlation functions with up to 95 terms. Results are rigorous lower bounds to the exact phase shifts. C1 NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. RP Bhatia, AK (reprint author), NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. NR 15 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 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD DEC PY 2002 VL 66 IS 6 AR 064702 DI 10.1103/PhysRevA.66.064702 PG 3 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 639YA UT WOS:000180656800118 ER PT J AU Choi, DI AF Choi, DI TI Collision of gravitationally bound Bose-Einstein condensates SO PHYSICAL REVIEW A LA English DT Article AB The dynamics of head-on collisions of gravitationally bound Bose-Einstein condensates is studied. A fully consistent Schrodinger-Poisson system is solved numerically assuming axial symmetry about the axis of collision. Here, the investigation is focused on the regime where the head-on collisions of binary condensates exhibit solitonic nature of the condensates, inelastic collision properties, collision-induced collapse instability (in the case of attractive atomic interaction), and characteristic interference patterns that depend on the phase information (speed) of the colliding condensates. C1 NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. Univ Space Res Assoc, Seabrook, MD 20706 USA. RP Choi, DI (reprint author), NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. NR 12 TC 16 Z9 16 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 DEC PY 2002 VL 66 IS 6 AR 063609 DI 10.1103/PhysRevA.66.063609 PG 5 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 639YA UT WOS:000180656800092 ER PT J AU Kok, P Lee, H Dowling, JP AF Kok, P Lee, H Dowling, JP TI Single-photon quantum-nondemolition detectors constructed with linear optics and projective measurements SO PHYSICAL REVIEW A LA English DT Article ID PHASE-SENSITIVE DETECTION; TELEPORTATION; LOGIC; ENTANGLEMENT; CONVERSION; STATES; CAVITY; LIGHT; ATOMS AB Optical quantum-nondemolition devices can provide essential tools for quantum information processing. Here, we describe several optical interferometers that signal the presence of a single photon in a particular input state without destroying it. We discuss both entanglement-assisted and nonentanglement-assisted interferometers, with ideal and realistic detectors. We found that the existing detectors with 88% quantum efficiency and single-photon resolution can yield output fidelities of up to 89%, depending on the input state. Furthermore, we construct expanded protocols to perform quantum-nondemolition detections of single photons that leave the polarization invariant. For detectors with 88% efficiency, we found polarization-preserving output fidelities of up to 98.5%. C1 CALTECH, Jet Prop Lab, Quantum Comp Technol Grp, Pasadena, CA 91109 USA. RP CALTECH, Jet Prop Lab, Quantum Comp Technol Grp, 4800 Oak Grove Dr,Sect 367,Mail Stop 126-347, Pasadena, CA 91109 USA. EM pieter.kok@jpl.nasa.gov RI Kok, Pieter/B-1658-2010; DOWLING, JONATHAN/L-2749-2013 NR 36 TC 116 Z9 118 U1 0 U2 6 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 DEC PY 2002 VL 66 IS 6 AR 063814 DI 10.1103/PhysRevA.66.063814 PG 9 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 639YA UT WOS:000180656800107 ER PT J AU Boutet, S Robinson, IK Hu, ZW Thomas, BR Chernov, AA AF Boutet, S Robinson, IK Hu, ZW Thomas, BR Chernov, AA TI Surface relaxation in protein crystals SO PHYSICAL REVIEW E LA English DT Article ID ATOMIC-FORCE MICROSCOPY; GROWTH MECHANISMS; CRYSTALLIZATION; LYSOZYME; MICROGRAVITY; CANAVALIN; KINETICS; VIRUS; AFM AB Surface x-ray diffraction measurements were performed on (111) growth faces of crystals of the cellular iron-storage protein, horse spleen ferritin. Crystal truncation rods (CTR) were measured. A fit of the measured profile of the CTR revealed a surface roughness of 48+/-4.5 Angstrom and a top layer spacing contraction of 3.9+/-1.5%. In addition to the peak from the CTR, the rocking curves of the crystals displayed unexpected extra peaks. Multiple scattering is demonstrated to account for them. Future applications of the method could allow the exploration of hydration effects on the growth of protein crystals. C1 Univ Illinois, Dept Phys, Urbana, IL 61801 USA. NASA, George C Marshall Space Flight Ctr, Univ Space Res Assoc, Huntsville, AL 35875 USA. RP Boutet, S (reprint author), Univ Illinois, Dept Phys, 1110 W Green St, Urbana, IL 61801 USA. NR 28 TC 2 Z9 2 U1 0 U2 6 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1539-3755 J9 PHYS REV E JI Phys. Rev. E PD DEC PY 2002 VL 66 IS 6 AR 061914 DI 10.1103/PhysRevE.66.061914 PN 1 PG 7 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA 635YD UT WOS:000180427000069 PM 12513324 ER PT J AU Qi, DW Luo, LS AF Qi, DW Luo, LS TI Transitions in rotations of a nonspherical particle in a three-dimensional moderate Reynolds number Couette flow SO PHYSICS OF FLUIDS LA English DT Article ID LATTICE-BOLTZMANN SIMULATIONS; PARTICULATE SUSPENSIONS; 3-DIMENSIONAL SPACE; SIMPLE SHEAR; EQUATION; FLUIDIZATION; DYNAMICS; INERTIA AB The rotational states of three-dimensional nonspherical particles including cylindrical and disk-shaped, as well as prolate and oblate, ellipsoidal in a Couette flow are studied by using a lattice Boltzmann simulation. We discover that rotation of a nonspherical particle exhibits several different states, depending on the ranges of the particle Reynolds numbers and the geometric shape of the particle. As the Reynolds number increases, the rotation transits from one state to another state. (C) 2002 American Institute of Physics. C1 Western Michigan Univ, Coll Engn & Appl Sci, Dept Paper & Printing Sci & Engn, Kalamazoo, MI 49008 USA. NASA, Langley Res Ctr, ICASE, Hampton, VA 23681 USA. RP Qi, DW (reprint author), Western Michigan Univ, Coll Engn & Appl Sci, Dept Paper & Printing Sci & Engn, Kalamazoo, MI 49008 USA. RI Luo, Li-Shi/A-4561-2011 OI Luo, Li-Shi/0000-0003-1215-7892 NR 21 TC 24 Z9 24 U1 0 U2 3 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 1070-6631 J9 PHYS FLUIDS JI Phys. Fluids PD DEC PY 2002 VL 14 IS 12 BP 4440 EP 4443 DI 10.1063/1.1517053 PG 4 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA 614FN UT WOS:000179177800031 ER PT J AU Carter, MD Baity, FW Barber, GC Goulding, RH Mori, Y Sparks, DO White, KF Jaeger, EF Chang-Diaz, FR Squire, JP AF Carter, MD Baity, FW Barber, GC Goulding, RH Mori, Y Sparks, DO White, KF Jaeger, EF Chang-Diaz, FR Squire, JP TI Comparing experiments with modeling for light ion helicon plasma sources SO PHYSICS OF PLASMAS LA English DT Article ID LOWER-HYBRID RESONANCE; WAVES; FREQUENCY; MODES; DISCHARGES AB The ability to obtain high plasma densities with high fractional ionization using readily available, low-cost components makes the helicon a candidate plasma source for many applications, including plasma rocket propulsion, fusion component testing, and materials processing. However, operation of a helicon can be a sensitive function of the magnetic field strength and geometry as well as the driving frequency, especially when using light feedstock gases such as hydrogen or helium. In this paper, results from a coupled rf and transport model are compared with experiments in the axially inhomogeneous Mini-Radio Frequency Test Facility [Goulding , Proceedings of the International Conference on Electromagnetics in Advanced Applications (ICEAA 99), Torino, Italy, 1999 (Litografia Geda, Torino, 1999), p. 107] (Mini-RFTF). Experimental observations of the radial shape of the density profile can be quantitatively reproduced by iteratively converging a high-resolution rf calculation including the rf parallel electric field with a transport model using reasonable choices for the transport parameters. The experimentally observed transition into the high density helicon mode is observed in the model, appearing as a nonlinear synergism between radial diffusion, the rf coupling to parallel electric fields that damp near the plasma edge, and propagation of helicon waves that collisionally damp near the axis of the device. Power deposition from various electric field components indicates that inductive coupling and absorption in the edge region can reduce the efficiency for high-density operation. The effects of absorption near the lower hybrid resonance in the near-field region of the antenna are discussed. Ponderomotive effects are also examined and found to be significant only in very low density and edge regions of the Mini-RFTF discharge. (C) 2002 American Institute of Physics. C1 Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. Kyushu Univ, Kasuga, Fukuoka 816, Japan. NASA, Adv Space Propuls Lab, Houston, TX 77059 USA. RP Carter, MD (reprint author), Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RI Goulding, Richard/C-5982-2016 OI Goulding, Richard/0000-0002-1776-7983 NR 34 TC 35 Z9 35 U1 2 U2 10 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 1070-664X J9 PHYS PLASMAS JI Phys. Plasmas PD DEC PY 2002 VL 9 IS 12 BP 5097 EP 5110 DI 10.1063/1.1519539 PG 14 WC Physics, Fluids & Plasmas SC Physics GA 617BQ UT WOS:000179340700030 ER PT J AU Sarrazin, P Blake, D Bish, D Vaniman, D Chipera, S Collins, SA Elliott, ST AF Sarrazin, P Blake, D Bish, D Vaniman, D Chipera, S Collins, SA Elliott, ST TI Robotic search for ices and hydrous minerals at the lunar poles using a combined X-ray diffraction and fluorescence instrument SO PLANETARY AND SPACE SCIENCE LA English DT Article AB There is a growing body of evidence that points to the survival of water or hydrous minerals on the Moon and the potential for large aqueous reservoirs in shadowed craters at the lunar poles. CheMin, an XRD/XRF instrument that is currently under development, could provide a definitive test of whether the polar hydrogen signal measured by the recent Lunar Prospector mission is an indication of a significant water reservoir or merely reflects an anomalously rich accumulation of solar-wind hydrogen. Proposed enhancements of CheMin could be used in conjunction with a drilling system capable of penetrating the upper few tens of centimeters of the lunar regolith to search for ices or hydrous minerals. This advanced version of the CheMin instrument would be within the size, mass, and power constraints of Ariane 5 micromissions. (C) 2002 Published by Elsevier Science Ltd. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. ENESAD, F-21079 Dijon, France. Los Alamos Natl Lab, EES 1, Los Alamos, NM 87545 USA. CALTECH, Jet Prop Lab, Detector Adv Dev, Pasadena, CA 91109 USA. RP Sarrazin, P (reprint author), ENESAD, 21 Bd O Serres, F-21800 Quetigny, France. NR 10 TC 6 Z9 7 U1 2 U2 3 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0032-0633 J9 PLANET SPACE SCI JI Planet Space Sci. PD DEC PY 2002 VL 50 IS 14-15 BP 1361 EP 1368 AR PII S0032-0633(02)00126-5 DI 10.1016/S0032-0633(02)00126-5 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 628MC UT WOS:000179998400008 ER PT J AU Bauer, JM Meech, KJ Fernandez, YR Farnham, TL Roush, TL AF Bauer, JM Meech, KJ Fernandez, YR Farnham, TL Roush, TL TI Observations of the Centaur 1999 UG(5): Evidence of a unique outer solar system surface SO PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF THE PACIFIC LA English DT Article ID KUIPER-BELT OBJECTS; WATER ICE; PHYSICAL-PROPERTIES; PHOTOMETRY; CU26; LIGHTCURVES; ASBOLUS; CHIRON; DISK AB The outer solar system body 1999 UG(5) is a Centaur of medium brightness and slightly redder color when compared to other Centaurs. Similar to at least 1/5 of the known Centaurs, it is a Saturn-crosser with a mean orbital distance between Saturn and Uranus. We present optical photometry data and near-IR spectra obtained during 2000 September, November, and December. We find a rotation period of 13.41 +/- 0.04 hr with an amplitude of 0.102 +/- 0.005 mag and a phase curve with a Lumme-Bowell G value of -0.13 +/- 0.02. BVRI colors are reported, and they confirm the red spectral gradient observed previously. Our spectra reveal that this redward slope extends into near-IR wavelengths and indicates possible localized differences in the surface composition. C1 Univ Hawaii, Inst Astron, Honolulu, HI 96822 USA. Univ Texas, Dept Astron, Austin, TX 78712 USA. NASA, Ames Res Ctr, Div Space Sci, Planetary Syst Branch, Moffett Field, CA 94035 USA. RP Univ Hawaii, Inst Astron, 2680 Woodlawn Dr, Honolulu, HI 96822 USA. NR 41 TC 32 Z9 32 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-6280 EI 1538-3873 J9 PUBL ASTRON SOC PAC JI Publ. Astron. Soc. Pac. PD DEC PY 2002 VL 114 IS 802 BP 1309 EP 1321 DI 10.1086/344586 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 617ZD UT WOS:000179390300002 ER PT J AU Badhwar, GD Huff, H Wilkins, R Thibeault, S AF Badhwar, GD Huff, H Wilkins, R Thibeault, S TI Comparison of graphite, aluminum, and TransHab shielding material characteristics in a high-energy neutron field SO RADIATION MEASUREMENTS LA English DT Article DE space radiation; shielding materials; radiation protection ID RESPONSE FUNCTION; RADIATION; SPECTRA AB Space radiation transport models clearly show that low atomic weight materials provide a better shielding protection for interplanetary human missions than high atomic weight materials. These model studies have concentrated on shielding properties against charged paricles. A light-weight, inflatable habitat module called TransHab was built and shown to provide adequate protection against micrometeoroid impacts and good shielding properties against charged particle radiation in the International Space Station orbits. An experiment using a tissue equivalent proportional counter, to study the changes in dose and lineal energy spectra with graphite, aluminum, and a TransHab build-up as shielding, was carried out at the Los Alamos Nuclear Science Center neutron facility. It is a continuation of a previous study using regolith and doped polyethylene materials. This paper describes the results and their comparison with the previous study. Published by Elsevier Science Ltd. C1 Prairie View A&M Univ, Ctr Appl Radiat Res, Prairie View, TX 77446 USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Wilkins, R (reprint author), Prairie View A&M Univ, Ctr Appl Radiat Res, Prairie View, TX 77446 USA. NR 7 TC 4 Z9 5 U1 0 U2 6 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1350-4487 J9 RADIAT MEAS JI Radiat. Meas. PD DEC PY 2002 VL 35 IS 6 BP 545 EP 549 AR PII S1350-4487(01)00271-2 DI 10.1016/S1350-4487(01)00271-2 PG 5 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 623UK UT WOS:000179721100001 PM 12455499 ER PT J AU Badhwar, GD Robbins, DE Gibbons, F Braby, LA AF Badhwar, GD Robbins, DE Gibbons, F Braby, LA TI Response of a tissue equivalent proportional counter to neutrons SO RADIATION MEASUREMENTS LA English DT Article DE neutron; microdosimetry; high LET radiation ID COSMIC-RADIATION; SHUTTLE AB The absorbed dose as a function of lineal energy was measured at the CERN-EC Reference-field Facility (CERF) using a 512-channel tissue equivalent proportional counter (TEPC), and neutron dose equivalent response evaluated. Although there are some differences, the measured dose equivalent is in agreement with that measured by the 16-channel HANDI tissue equivalent counter. Comparison of TEPC measurements with those made by a silicon solid-state detector for low linear energy transfer particles produced by the same beam, is presented. The measurements show that about 4% of dose equivalent is delivered by particles heavier than protons generated in the conducting tissue equivalent plastic. (C) 2002 Elsevier Science Ltd. All rights reserved. C1 Texas A&M Univ, College Stn, TX 77843 USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. USRA, Houston, TX USA. Lockheed Martin, Houston, TX USA. RP Braby, LA (reprint author), Texas A&M Univ, College Stn, TX 77843 USA. NR 10 TC 7 Z9 7 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1350-4487 J9 RADIAT MEAS JI Radiat. Meas. PD DEC PY 2002 VL 35 IS 6 BP 551 EP 556 AR PII S1350-4487(01)00273-6 DI 10.1016/S1350-4487(01)00273-6 PG 6 WC Nuclear Science & Technology SC Nuclear Science & Technology GA 623UK UT WOS:000179721100002 PM 12455500 ER PT J AU Tian, YH Woodcock, CE Wang, YJ Privette, JL Shabanov, NV Zhou, LM Zhang, Y Buermann, W Dong, JR Veikkanen, B Hame, T Andersson, K Ozdogan, M Knyazikhin, Y Myneni, RB AF Tian, YH Woodcock, CE Wang, YJ Privette, JL Shabanov, NV Zhou, LM Zhang, Y Buermann, W Dong, JR Veikkanen, B Hame, T Andersson, K Ozdogan, M Knyazikhin, Y Myneni, RB TI Multiscale analysis and validation of the MODIS LAI product - I. Uncertainty assessment SO REMOTE SENSING OF ENVIRONMENT LA English DT Article ID LEAF-AREA INDEX; SPATIAL-RESOLUTION; SATELLITE MEASUREMENTS; SURFACE; MODELS; ALBEDO; SEGMENTATION; SCALE; SITU AB The development of appropriate ground-based validation techniques is critical to assessing uncertainties associated with satellite data-based products. Here we present a method for validation of the Moderate Resolution Imaging Spectroradiometer (MODIS) Leaf Area Index (LAI) product with emphasis on the sampling strategy for field data collection. This paper, the first of two-part series, details the procedures used to assess uncertainty of the MODIS LAI product. LAI retrievals from 30 to ETM+ data were first compared to field measurements from the SAFARI 2000 wet season campaign. The ETM+ based LAI map was thus as a reference to specify uncertainties in the LAI fields produced from MODIS data (250-, 500-, and 1000-m resolutions) simulated from ETM+. Because of high variance of LAI measurements over short distances and difficulties of matching measurements and image data, a patch-by-patch comparison method, which is more realistically implemented on a routine basis for validation, is proposed. Consistency between LAI retrievals from 30 to ETM+ data and field measurements indicates satisfactory performance of the algorithm. Values of LAI estimated from a spatially heterogeneous scene depend strongly on the spatial resolution of the image scene. The results indicate that the MODIS algorithm will underestimate LAI values by about 5% over the Maim site if the scale of the algorithm is not matched to the resolution of the data. (C) 2002 Elsevier Science Inc. All rights reserved. C1 Georgia Inst Technol, Sch Earth & Atmospher Sci, Atlanta, GA 30332 USA. Boston Univ, Dept Geog, Boston, MA 02215 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. VTT Automat, Remote Sensing, Espoo 02044, Finland. RP Tian, YH (reprint author), Georgia Inst Technol, Sch Earth & Atmospher Sci, 221 Bobby Dodd Way, Atlanta, GA 30332 USA. RI Privette, Jeffrey/G-7807-2011; Zhou, Liming/A-2688-2012; Myneni, Ranga/F-5129-2012; OI Privette, Jeffrey/0000-0001-8267-9894; Ozdogan, Mutlu/0000-0002-1707-3375 NR 38 TC 121 Z9 144 U1 1 U2 20 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD DEC PY 2002 VL 83 IS 3 BP 414 EP 430 AR PII S0034-4257(02)00047-0 DI 10.1016/S0034-4257(02)00047-0 PG 17 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA 616WH UT WOS:000179326000005 ER PT J AU Tian, YH Woodcock, CE Wang, YJ Privette, JL Shabanova, NV Zhou, LM Zhang, Y Buermann, W Dong, JR Veikkanen, B Hame, T Andersson, K Ozdogan, M Knyazikhin, Y Myneni, RB AF Tian, YH Woodcock, CE Wang, YJ Privette, JL Shabanova, NV Zhou, LM Zhang, Y Buermann, W Dong, JR Veikkanen, B Hame, T Andersson, K Ozdogan, M Knyazikhin, Y Myneni, RB TI Multiscale analysis and validation of the MODIS LAI product - II. Sampling strategy SO REMOTE SENSING OF ENVIRONMENT LA English DT Article ID HIERARCHICAL SCENE MODELS; IMAGES; VARIOGRAMS AB The development of appropriate ground-based validation techniques is critical to assessing uncertainties associated with satellite data-based products. In this paper, the second of a two-part series, we present a method for validation of the Moderate Resolution Imaging Spectroradiometer Leaf Area Index (MODIS LAI) product with emphasis on the sampling strategy for field data collection. Using a hierarchical scene model, we divided 30-m resolution LAI and NDVI images from Maun (Botswana), Harvard Forest (USA) and Ruokulahti Forest (Finland) into individual scale images of classes, region and pixel. Isolating the effects associated with different landscape scales through decomposition of semivariograms not only shows the relative contribution of different characteristic scales to the overall variation, but also displays the spatial structure of the different scales within a scene. We find that (1) patterns of variance at the class, region and pixel scale at these sites are different with respect to the dominance in order of the three levels of landscape organization within a scene; (2) the spatial structure of LAI shows similarity across the three sites, that is, ranges of semivariograms from scale of pixel, region and class are less than 1000 in. Knowledge gained from these analyses aids in formulation of sampling strategies for validation of biophysical products derived from moderate resolution sensors such as MODIS. For a homogeneous (within class) site, where the scales of class and region account for most of the spatial variation, a sampling strategy should focus more on using accurate land cover maps and selection of regions. However, for a heterogeneous (within class) site, accurate point measurements and GPS readings are needed. (C) 2002 Elsevier Science Inc. All rights reserved. C1 Georgia Inst Technol, Sch Earth & Atmospher Sci, Atlanta, GA 30332 USA. Boston Univ, Dept Geog, Boston, MA 02215 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. VTT Automat, Remote Sensing, Espoo 02044, Finland. RP Tian, YH (reprint author), Georgia Inst Technol, Sch Earth & Atmospher Sci, 221 Bobby Dodd Way, Atlanta, GA 30332 USA. RI Privette, Jeffrey/G-7807-2011; Zhou, Liming/A-2688-2012; Myneni, Ranga/F-5129-2012; OI Privette, Jeffrey/0000-0001-8267-9894; Ozdogan, Mutlu/0000-0002-1707-3375 NR 18 TC 58 Z9 65 U1 2 U2 14 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD DEC PY 2002 VL 83 IS 3 BP 431 EP 441 AR PII S0034-4257(02)00058-5 DI 10.1016/S0034-4257(02)00058-5 PG 11 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA 616WH UT WOS:000179326000006 ER PT J AU Landis, GA AF Landis, GA TI Number, please? SO SCIENTIFIC AMERICAN LA English DT Letter C1 NASA, John Glenn Res Ctr, Cleveland, OH 44135 USA. RP Landis, GA (reprint author), NASA, John Glenn Res Ctr, Cleveland, OH 44135 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU SCI AMERICAN INC PI NEW YORK PA 415 MADISON AVE, NEW YORK, NY 10017 USA SN 0036-8733 J9 SCI AM JI Sci.Am. PD DEC PY 2002 VL 287 IS 6 BP 20 EP 20 PG 1 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 619RF UT WOS:000179489600011 ER PT J AU Gehrels, N Piro, L Leonard, PJT AF Gehrels, N Piro, L Leonard, PJT TI The brightest in the universe - gamma-ray bursts herald the birth of a black hole SO SCIENTIFIC AMERICAN LA English DT Article ID PROGENITOR C1 NASA, Goddard Space Flight Ctr, Gamma Ray Cosm Ray & Gravitat Wave Branch, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RI Gehrels, Neil/D-2971-2012; PIRO, LUIGI/E-4954-2013 OI PIRO, LUIGI/0000-0003-4159-3984 NR 6 TC 5 Z9 5 U1 0 U2 1 PU SCI AMERICAN INC PI NEW YORK PA 415 MADISON AVE, NEW YORK, NY 10017 USA SN 0036-8733 J9 SCI AM JI Sci.Am. PD DEC PY 2002 VL 287 IS 6 BP 84 EP 91 PG 8 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 619RF UT WOS:000179489600031 PM 12469650 ER PT J AU Bindschadler, RA Bentley, CR AF Bindschadler, RA Bentley, CR TI On thin ice? Western Antarctica's ice sheet SO SCIENTIFIC AMERICAN LA English DT Article C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Bindschadler, RA (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 3 TC 10 Z9 10 U1 0 U2 0 PU SCI AMERICAN INC PI NEW YORK PA 415 MADISON AVE, NEW YORK, NY 10017 USA SN 0036-8733 J9 SCI AM JI Sci.Am. PD DEC PY 2002 VL 287 IS 6 BP 98 EP 105 PG 8 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 619RF UT WOS:000179489600033 PM 12469652 ER PT J AU Whitelam, S Ashbourn, JMA Bingham, R Shukla, PK Spicer, DS AF Whitelam, S Ashbourn, JMA Bingham, R Shukla, PK Spicer, DS TI Alfven wave heating and acceleration of plasmas in the solar transition region producing jet-like eruptive activity SO SOLAR PHYSICS LA English DT Article ID H-ALPHA; EUV OBSERVATIONS; FLUX TUBES; SPICULES; MACROSPICULES; ATMOSPHERE; SURGES; FLARES; SIMULATIONS; NETWORK AB We present an analysis of observations and theory of selected transition-region phenomena, concentrating on small scale jet-like structures known as spicules and macrospicules. We examine a number of mechanisms that may be responsible for their formation and conclude that Alfven waves could provide the necessary acceleration through the ponderomotive force and dissipation for heating forming a beam or jet like structure. In applying the Alfven wave model we make no fundamental distinction between spicules and macrospicules. In this respect we consider them to be manifestations of the same phenomenon on different scales. We predict that the most effective Alfven waves have frequencies around 1 Hz and amplitudes of 1 V m(-1). The resulting plasma jet sets up plasma conditions suitable for creating rotating structures which are also observed. C1 Univ Oxford, Trinity Coll, Oxford OX1 3BH, England. Univ Oxford, Inst Math, Oxford OX1 3LB, England. Rutherford Appleton Lab, Didcot OX11 0QX, Oxon, England. Univ Strathclyde, Glasgow G1 1XQ, Lanark, Scotland. Ruhr Univ Bochum, Inst Theoret Phys 4, D-44780 Bochum, Germany. NASA, Goddard Space Flight Ctr, NASA Ctr Computat Sci, Greenbelt, MD 20771 USA. RP Whitelam, S (reprint author), Univ Oxford, Trinity Coll, Oxford OX1 3BH, England. RI Shukla, Padma Kant/E-9077-2011 NR 68 TC 9 Z9 9 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-0938 J9 SOL PHYS JI Sol. Phys. PD DEC PY 2002 VL 211 IS 1-2 BP 199 EP 219 DI 10.1023/A:1022408206824 PG 21 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 647BQ UT WOS:000181071700014 ER PT J AU Hathaway, DH Wilson, RM Reichmann, EJ AF Hathaway, DH Wilson, RM Reichmann, EJ TI Group sunspot numbers: Sunspot cycle characteristics SO SOLAR PHYSICS LA English DT Article ID SOLAR-ACTIVITY RECONSTRUCTION; MAUNDER MINIMUM; SIZE; LENGTH; RECORD AB We examine the 'Group' sunspot numbers constructed by Hoyt and Schatten to determine their utility in characterizing the solar activity cycle. We compare smoothed monthly Group sunspot numbers to Zurich (International) sunspot numbers, 10.7-cm radio flux, and total sunspot area. We find that the Zilrich numbers follow the 10.7-cm radio flux and total sunspot area measurements only slightly better than the Group numbers. We examine several significant characteristics of the sunspot cycle using both Group numbers and Zilrich numbers. We find that the 'Waldmeier Effect' - the anticorrelation between cycle amplitude and the elapsed time between minimum and maximum of a cycle - is much more apparent in the Zilrich numbers. The 'Amplitude- Period Effect' - the anti-correlation between cycle amplitude and the length of the previous cycle from minimum to minimum - is also much more apparent in the Zilrich numbers. The 'Amplitude -Minimum Effect' - the correlation between cycle amplitude and the activity level at the previous (onset) minimum is equally apparent in both the Zilrich numbers and the Group numbers. The 'Even-Odd Effect' - in which odd-numbered cycles are larger than their even-numbered precursors - is somewhat stronger in the Group numbers but with a tighter relationship in the Zilrich numbers. The 'Secular Trend' - the increase in cycle amplitudes since the Maunder Minimum - is much stronger in Group numbers. After removing this trend we find little evidence for multi-cycle periodicities like the 80-year Gleissberg cycle or the two- and three-cycle periodicities. We also find little evidence for a correlation between the amplitude of a cycle and its period or for a bimodal distribution of cycle periods. We conclude that the Group numbers are most useful for extending the sunspot cycle data further back in time and thereby adding more cycles and improving the statistics. However, the Zilrich numbers are slightly more useful for characterizing the on-going levels of solar activity. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Hathaway, DH (reprint author), NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. NR 32 TC 139 Z9 144 U1 2 U2 8 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-0938 J9 SOL PHYS JI Sol. Phys. PD DEC PY 2002 VL 211 IS 1-2 BP 357 EP 370 DI 10.1023/A:1022425402664 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 647BQ UT WOS:000181071700024 ER PT J AU Case, JL Manobianco, J Dianic, AV Wheeler, MM Harms, DE Parks, CR AF Case, JL Manobianco, J Dianic, AV Wheeler, MM Harms, DE Parks, CR TI Verification of high-resolution RAMS forecasts over East-Central Florida during the 1999 and 2000 summer months SO WEATHER AND FORECASTING LA English DT Article ID CENTENNIAL OLYMPIC GAMES; 29-KM ETA-MODEL; MICROPHYSICAL EVOLUTION; MOIST CONVECTION; MESOSCALE MODEL; PRECIPITATION; SYSTEM; SKILL; INITIALIZATION; DISTRIBUTIONS AB This paper presents an objective and subjective verification of a high-resolution configuration of the Regional Atmospheric Modeling System (RAMS) over east-central Florida during the 1999 and 2000 summer months. Centered on the Cape Canaveral Air Force Station (CCAFS), the innermost nested grid of RAMS has a horizontal grid spacing of 1.25 km, thereby providing forecasts capable of modeling finescale phenomena such as ocean and river breezes, and convection. The RAMS is run operationally at CCAFS within the Eastern Range Dispersion Assessment System (ERDAS), in order to provide emergency response guidance during space operations. ERDAS uses RAMS wind and temperature fields for input into ERDAS diffusion algorithms; therefore, the accuracy of dispersion predictions is highly dependent on the accuracy of RAMS forecasts. The most substantial error in RAMS over east-central Florida is a surface-based cold temperature bias, primarily during the daylight hours. At the Shuttle Landing Facility, the RAMS point error statistics are not substantially different than the National Centers for Environment Prediction Eta Model; however, an objective evaluation consisting of only point error statistics cannot adequately determine the added value of a high-resolution model configuration. Thus, results from a subjective evaluation of the RAMS forecast sea breeze and thunderstorm initiation on the 1.25-km grid are also presented. According to the subjective verification of the Florida east coast sea breeze, the RAMS categorical and skill scores exceeded that of the Eta Model predictions in most instances. The RAMS skill scores in predicting thunderstorm initiation are much lower than the sea-breeze evaluation scores, likely resulting from the lack of a sophisticated data assimilation scheme in the current operational configuration. C1 ENSCO Inc, Cocoa Beach, FL 32931 USA. NASA, Appl Meteorol Unit, Kennedy Space Ctr, FL 32899 USA. USAF, Weather Squadron 45, Patrick Air Force Base, FL USA. ACTA Inc, Cape Canaveral, FL USA. 45th Space Wing E Range Safety, Patrick Air Force Base, FL USA. RP ENSCO Inc, 1980 N Atlantic Ave,Suite 230, Cocoa Beach, FL 32931 USA. EM case.jonathan@ensco.com NR 43 TC 23 Z9 23 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0882-8156 EI 1520-0434 J9 WEATHER FORECAST JI Weather Forecast. PD DEC PY 2002 VL 17 IS 6 BP 1133 EP 1151 DI 10.1175/1520-0434(2002)017<1133:VOHRRF>2.0.CO;2 PG 19 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 630XF UT WOS:000180135600001 ER PT J AU Whaley, SD Minello, TJ AF Whaley, SD Minello, TJ TI The distribution of benthic infauna of a Texas salt marsh in relation to the marsh edge SO WETLANDS LA English DT Article DE salt marsh; benthic infauna; polychaetes; edge; elevation; Spartina alterniflora marsh; oligochaetes ID CORDGRASS SPARTINA-ALTERNIFLORA; PENAEUS-AZTECUS IVES; SMALL-SCALE PATTERNS; FUNDULUS-HETEROCLITUS; NORTH-CAROLINA; TIDAL MARSH; GALVESTON BAY; BROWN SHRIMP; NEKTON USE; SELECTIVE PREDATION AB Coastal salt marshes in the northern Gulf of Mexico are often highly fragmented, with a large amount of marsh edge, the interface between the vegetated marsh surface and shallow open water. Nekton predators, including many juvenile fishery species, aggregate near this marsh edge, and benthic infaunal populations are a primary source of prey for many of these predators. We examined the fine-scale (1-10 m) distributions of benthic infauna in relation to the edge of a Texas, USA salt marsh. Every six weeks for nearly a year, we sampled marsh sediments at five locations: on nonvegetated bottom 1 m from the marsh edge and on the vegetated marsh surface at 1, 3, 5, and 10 m from the edge. Surface-dwelling annelid worms and peracarid crustaceans were most abundant in low-elevation sediments near the marsh edge for most sampling periods. Because the marsh slope varied within the study area, we could distinguish between correlative relationships with elevation and distance from the marsh edge. Distributions of common surfaced-welling species were often unrelated to elevation but almost always negatively related to distance from the marsh edge. Abundances of near-surface direct deposit feeders and omnivores were related to both distance from edge and elevation. In contrast to surface dwellers, densities of abundant subsurface deposit feeders (mainly oligochaetes) were frequently greatest in sediments located away from the marsh edge. Surface and near-surface dwelling infauna are an important prey resource for nekton, including many juvenile fishery species that concentrate near the marsh edge. Populations of these infaunal prey fluctuated seasonally, with the greatest densities occurring during winter and early spring when predator abundances are generally low. Infaunal densities decreased dramatically near the marsh edge from the late spring through early fall, and this decrease coincides with historically high seasonal densities of nekton predators. Our data suggest that there is a strong trophic link between infauna and nekton near the marsh edge and that this relationship contributes to the high fishery productivity derived from Gulf Coast marshes. C1 Natl Marine Fisheries Serv, SE Fisheries Sci Ctr, Galveston, TX 77551 USA. RP Whaley, SD (reprint author), Florida Marine Res Inst, 100 8th Ave SE, St Petersburg, FL 33701 USA. EM Shannon.Whaley@fwc.state.flu.us NR 80 TC 30 Z9 32 U1 2 U2 14 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0277-5212 J9 WETLANDS JI Wetlands PD DEC PY 2002 VL 22 IS 4 BP 753 EP 766 DI 10.1672/0277-5212(2002)022[0753:TDOBIO]2.0.CO;2 PG 14 WC Ecology; Environmental Sciences SC Environmental Sciences & Ecology GA 632YU UT WOS:000180253100012 ER PT J AU De Chant, LJ Seidel, JA Kline, TR AF De Chant, LJ Seidel, JA Kline, TR TI Extension of a combined analytical/numerical initial value problem solver for unsteady periodic flow SO INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS LA English DT Article DE periodic flow; combined analytical/numerical method; aerodynamic mixing; ejector nozzle ID JET AB Here we describe analytical and numerical modifications that extend the Differential Reduced Ejector/mixer Analysis (DREA), a combined analytical/numerical, multiple species ejector/mixing code developed for preliminary design applications, to apply to periodic unsteady flow. An unsteady periodic flow modelling capability opens a range of pertinent simulation problems including pulse detonation engines (PDE), internal combustion engine ICE applications, mixing enhancement and more fundamental fluid dynamic unsteadiness, e.g. fan instability/vortex shedding problems. Although mapping between steady and periodic forms for a scalar equation is a classical problem in applied mathematics, we will show that extension to systems of equations and, moreover, problems with complex initial conditions are more challenging. Additionally, the inherent large gradient initial condition singularities that are characteristic of mixing flows and that have greatly influenced the DREA code formulation, place considerable limitations on the use of numerical solution methods. Fortunately, using the combined analytical-numerical form of the DREA formulation, a successful formulation is developed and described. Comparison of this method with experimental measurements for jet flows with excitation shows reasonable agreement with the simulation. Other flow fields are presented to demonstrate the capabilities of the model. As such, we demonstrate that unsteady periodic effects can be included within the simple, efficient, coarse grid DREA implementation that has been the original intent of the DREA development effort, namely, to provide a viable tool where more complex and expensive models are inappropriate. Copyright (C) 2002 John Wiley Sons, Ltd. C1 Analyt Entrainment LLC, Albuquerque, NM 87112 USA. NASA, Glenn Res Ctr, Prop Syst Anal Off, Cleveland, OH USA. RP De Chant, LJ (reprint author), Analyt Entrainment LLC, 1541 Summit Hills Dr NE, Albuquerque, NM 87112 USA. NR 30 TC 1 Z9 1 U1 1 U2 4 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX PO19 1UD, ENGLAND SN 0271-2091 J9 INT J NUMER METH FL JI Int. J. Numer. Methods Fluids PD NOV 30 PY 2002 VL 40 IS 9 BP 1163 EP 1186 DI 10.1002/fld.382 PG 24 WC Computer Science, Interdisciplinary Applications; Mathematics, Interdisciplinary Applications; Mechanics; Physics, Fluids & Plasmas SC Computer Science; Mathematics; Mechanics; Physics GA 621LW UT WOS:000179591300002 ER PT J AU Bourennane, M Karlsson, A Bjork, G Gisin, N Cerf, NJ AF Bourennane, M Karlsson, A Bjork, G Gisin, N Cerf, NJ TI Quantum key distribution using multilevel encoding: security analysis SO JOURNAL OF PHYSICS A-MATHEMATICAL AND GENERAL LA English DT Article ID UNCONDITIONAL SECURITY; CRYPTOGRAPHY; CLONING; DIMENSION; PROTOCOL; SYSTEMS; STATES; QUBITS AB We propose an extension of quantum key distribution based on encoding the key into quNits, i.e. quantum states in an N-dimensional Hilbert space. We,estimate both the mutual information between the legitimate parties and the eavesdropper, and the error rate, as a function of the dimension of the Hilbert space. We derive the information gained by an eavesdropper using optimal incoherent attacks and an upper bound on the legitimate party error rate that ensures unconditional security when the eavesdropper uses finite coherent eavesdropping attacks. We also consider realistic systems where we assume that the detector dark count probability is not negligible. C1 Univ Munich, Sekt Phys, D-80797 Munich, Germany. Max Planck Inst Quantum Opt, D-85748 Garching, Germany. Royal Inst Technol, Dept Microelect & Informat Technol, Electrum 229, SE-16440 Kista, Sweden. Univ Geneva, GAP Opt, Geneva 4, Switzerland. Free Univ Brussels, Ecole Polytech, B-1050 Brussels, Belgium. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Bourennane, M (reprint author), Univ Munich, Sekt Phys, D-80797 Munich, Germany. OI Karlsson, Anders/0000-0003-4599-1840 NR 30 TC 50 Z9 50 U1 0 U2 0 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0305-4470 J9 J PHYS A-MATH GEN JI J. Phys. A-Math. Gen. PD NOV 29 PY 2002 VL 35 IS 47 BP 10065 EP 10076 AR PII S0305-4470(02)25747-9 DI 10.1088/0305-4470/35/47/307 PG 12 WC Physics, Multidisciplinary; Physics, Mathematical SC Physics GA 633NG UT WOS:000180288900013 ER PT J AU Shindell, DT Faluvegi, G AF Shindell, DT Faluvegi, G TI An exploration of ozone changes and their radiative forcing prior to the chlorofluorocarbon era SO ATMOSPHERIC CHEMISTRY AND PHYSICS LA English DT Article ID STRATOSPHERIC WATER-VAPOR; SURFACE OZONE; CLIMATE-CHANGE; NORTHERN-HEMISPHERE; TROPOSPHERIC OZONE; MIDDLE ATMOSPHERE; AROSA SWITZERLAND; DOUBLED CO2; TRENDS; INCREASE AB Using historical observations and model simulations, we investigate ozone trends prior to the mid-1970s onset of halogen-induced ozone depletion. Though measurements are quite limited, an analysis based on multiple, independent data sets (direct and indirect) provides better constraints than any individual set of observations. We find that three data sets support an apparent long-term stratospheric ozone trend of -7.2+/-2.3 DU during 1957-1975, which modeling attributes primarily to water vapor increases. The results suggest that 20th century stratospheric ozone depletion may have been roughly 50% more than is generally supposed. Similarly, three data sets support tropospheric ozone increases over polluted Northern Hemisphere continental regions of 8.2+/-2.1 DU during this period, which are mutually consistent with the stratospheric trends. As with paleoclimate data, which is also based on indirect proxies and/or limited spatial coverage, these results must be interpreted with caution. However, they provide the most thorough estimates presently available of ozone changes prior to the coincident onset of satellite data and halogen dominated ozone changes. If these apparent trends were real, the radiative forcing by stratospheric ozone since the 1950s would then have been -0.15+/-0.05 W/m(2), and -0.2 W/m(2) since the preindustrial. For tropospheric ozone, it would have been 0.38+/-0.10 W/m(2) since the late 1950s. Combined with even a very conservative estimate of tropospheric ozone forcing prior to that time, this would be larger than current estimates since 1850 which are derived from models that are even less well constrained. These calculations demonstrate the importance of gaining a better understanding of historical ozone changes. C1 NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Columbia Univ, Ctr Climate Syst Res, New York, NY USA. RP Shindell, DT (reprint author), NASA, Goddard Inst Space Studies, New York, NY 10025 USA. RI Shindell, Drew/D-4636-2012 NR 44 TC 15 Z9 15 U1 0 U2 0 PU EUROPEAN GEOPHYSICAL SOC PI KATLENBURG-LINDAU PA MAX-PLANCK-STR 13, 37191 KATLENBURG-LINDAU, GERMANY SN 1680-7324 J9 ATMOS CHEM PHYS JI Atmos. Chem. Phys. PD NOV 28 PY 2002 VL 2 BP 363 EP 374 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 621EU UT WOS:000179576200001 ER PT J AU Wrkich, J Matthews, D Kanik, I Trajmar, S Khakoo, MA AF Wrkich, J Matthews, D Kanik, I Trajmar, S Khakoo, MA TI Differential cross-sections for the electron impact excitation of the B (1)Sigma(+)(u), c (3)Pi(u), a (3)Sigma(+)(g), C (1)Pi(u), E, F (1)Sigma(+)(g) and e (3)Sigma(+)(u) states of molecular hydrogen SO JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS LA English DT Article ID R-MATRIX METHOD; H-2; 3-SIGMA-U+; REGION; H2 AB Using energy loss spectroscopy, normalized differential and integral cross-sections for the electron impact excitation of the lowest bound excited states of H-2 from the ground X (1)Sigma(g)(+) state have been measured at 17.5, 20 and 30 eV impact energies and for scattering angles from 5degrees up to 130degrees. These differential cross-sections (DCSs) are an effort to improve those taken previously (Khakoo M A and Trajmar S 1986b Phys. Rev. A 34 146). Here a more sophisticated electron spectrometer and a more accurate spectrum analysis code is used to unfold the energy loss spectra. The results are compared with earlier DCS measurements for the B (1)Sigma(u)(+), c (3)Pi(u), a (3)Sigma(g)(+), C (1)Pi(u) states of H-2 and with existing theoretical results for the B (1)Sigma(u)(+), c(3)Pi(u), a (3)Sigma(g)(+), C (1)Pi(u), E, F (1)Sigma(g)(+) and e (3)Sigma(u)(+) states. C1 Calif State Univ Fullerton, Dept Phys, Fullerton, CA 92834 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Wrkich, J (reprint author), Calif State Univ Fullerton, Dept Phys, Fullerton, CA 92834 USA. NR 28 TC 24 Z9 25 U1 1 U2 5 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0953-4075 EI 1361-6455 J9 J PHYS B-AT MOL OPT JI J. Phys. B-At. Mol. Opt. Phys. PD NOV 28 PY 2002 VL 35 IS 22 BP 4695 EP 4709 AR PII S0953-4075(02)37292-4 DI 10.1088/0953-4075/35/22/311 PG 15 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 631GE UT WOS:000180159100015 ER PT J AU Ting, DZY Cartoixa, X AF Ting, DZY Cartoixa, X TI Resonant interband tunneling spin filter SO APPLIED PHYSICS LETTERS LA English DT Article ID QUANTUM-WELLS; HETEROSTRUCTURES; RELAXATION; CARRIERS AB We propose an InAs/GaSb/AlSb-based asymmetric resonant interband tunneling diode as a spin filter. The interband design exploits large valence band spin-orbit interaction to provide strong spin selectivity, without suffering from fast hole spin relaxation. Spin filtering efficiency is also enhanced by the reduction of tunneling through quasibound states near the zone center, where spin spitting vanishes and spin selectivity is difficult. Our calculations show that, when coupled with an emitter or collector capable of lateral momentum selectivity, the asymmetric resonant interband tunneling diode can achieve significant spin filtering in conventional nonmagnetic semiconductor heterostructures under zero magnetic field. (C) 2002 American Institute of Physics. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. CALTECH, TJ Watson Sr Labs Appl Phys, Pasadena, CA 91109 USA. RP Ting, DZY (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 16 TC 44 Z9 44 U1 0 U2 8 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD NOV 25 PY 2002 VL 81 IS 22 BP 4198 EP 4200 DI 10.1063/1.1524700 PG 3 WC Physics, Applied SC Physics GA 617BR UT WOS:000179340800033 ER PT J AU Lindsay, JF Brasier, MD AF Lindsay, JF Brasier, MD TI A comment on tectonics and the future of terrestrial life - reply SO PRECAMBRIAN RESEARCH LA English DT Editorial Material ID PLATE-TECTONICS; NORTHERN AUSTRALIA; DICHOTOMY; MARS; ISOTOPES; OXYGEN; IMPACT; BASINS; ORIGIN C1 NASA, Lyndon B Johnson Space Ctr, JSC Astrobiol Inst, Houston, TX 77058 USA. Univ Oxford, Dept Earth Sci, Oxford OX1 3PR, England. RP NASA, Lyndon B Johnson Space Ctr, JSC Astrobiol Inst, Houston, TX 77058 USA. EM john.f.lindsay1@jsc.nasa.gov NR 22 TC 5 Z9 6 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0301-9268 EI 1872-7433 J9 PRECAMBRIAN RES JI Precambrian Res. PD NOV 25 PY 2002 VL 118 IS 3-4 BP 293 EP 295 AR PII S0301-9268(02)00144-4 DI 10.1016/S0301-9268(02)00144-4 PG 3 WC Geosciences, Multidisciplinary SC Geology GA 626EA UT WOS:000179858300009 ER PT J AU Ksendzov, A Mansour, K AF Ksendzov, A Mansour, K TI Hybrid fabrication of single frequency semiconductor lasers SO ELECTRONICS LETTERS LA English DT Article AB While simple Fabry-Perot (F-P) semiconductor lasers are readily available on the market, singlemode lasers are produced only in limited spectral intervals, mainly of interest to optical communications. A hybridisation scheme has been devised that, given a suitable F-P gain medium, enables the fabrication of small, mechanically robust single frequency lasers in a wide spectral range, limited only by the transparency of the SiON material. C1 Jet Propuls Lab, Pasadena, CA 91109 USA. RP Ksendzov, A (reprint author), Jet Propuls Lab, 4800 Oak Grove Dr Pasadena, Pasadena, CA 91109 USA. NR 3 TC 0 Z9 0 U1 0 U2 0 PU IEE-INST ELEC ENG PI HERTFORD PA MICHAEL FARADAY HOUSE SIX HILLS WAY STEVENAGE, HERTFORD SG1 2AY, ENGLAND SN 0013-5194 J9 ELECTRON LETT JI Electron. Lett. PD NOV 21 PY 2002 VL 38 IS 24 BP 1536 EP 1537 DI 10.1049/el:20021043 PG 2 WC Engineering, Electrical & Electronic SC Engineering GA 624FF UT WOS:000179749100032 ER PT J AU Brown, P Spalding, RE ReVelle, DO Tagliaferri, E Worden, SP AF Brown, P Spalding, RE ReVelle, DO Tagliaferri, E Worden, SP TI The flux of small near-Earth objects colliding with the Earth SO NATURE LA English DT Article ID ASTEROIDS; BOLIDES; METEOROIDS; IMPACTS AB Asteroids with diameters smaller than similar to50-100 m that collide with the Earth usually do not hit the ground as a single body; rather, they detonate in the atmosphere(1). These small objects can still cause considerable damage, such as occurred near Tunguska(2), Siberia, in 1908. The flux of small bodies is poorly constrained, however, in part because ground-based observational searches pursue strategies that lead them preferentially to find larger objects(3). ATunguska-class event - the energy of which we take to be equivalent to 10 megatons of TNT - was previously estimated to occur every 200 - 300 years, with the largest annual airburst calculated to be similar to20 kilotons (kton) TNT equivalent (ref. 4). Here we report satellite records of bolide detonations in the atmosphere over the past 8.5 years. We find that the flux of objects in the 1-10-m size range has the same power-law distribution as bodies with diameters > 50 m. From this we estimate that the Earth is hit on average annually by an object with similar to5 kton equivalent energy, and that Tunguska-like events occur about once every 1,000 years. C1 Univ Western Ontario, Dept Phys & Astron, London, ON N6A 3K7, Canada. Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Sandia Natl Labs, Albuquerque, NM 87185 USA. ET Space Syst, Camarillo, CA 93012 USA. US Space Command, Directorate Operat, Peterson AFB, Colorado Springs, CO 80914 USA. RP Brown, P (reprint author), Univ Western Ontario, Dept Phys & Astron, London, ON N6A 3K7, Canada. NR 29 TC 168 Z9 170 U1 2 U2 20 PU NATURE PUBLISHING GROUP PI LONDON PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD NOV 21 PY 2002 VL 420 IS 6913 BP 294 EP 296 DI 10.1038/nature01238 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 617BM UT WOS:000179340400035 PM 12447433 ER PT J AU Tratt, DM Menzies, RT Chiao, MP Cutten, DR Rothermel, J Hardesty, RM Howell, JN Durden, SL AF Tratt, DM Menzies, RT Chiao, MP Cutten, DR Rothermel, J Hardesty, RM Howell, JN Durden, SL TI Airborne Doppler lidar investigation of the wind-modulated sea-surface angular retroreflectance signature SO APPLIED OPTICS LA English DT Article ID SPECTRAL REFLECTANCE; OCEAN SURFACE; BACKSCATTER; WHITECAPS; WATERS; SPEED; CALIBRATION; VECTORS; SCANNER; FIELDS AB Concurrent measurements of sea-surface retroreflectance and associated wind velocity acquired with an airborne CO2 Doppler lidar are described. These observations provide further insight into thermal infrared optical phenomenology of air-sea interface processes, contribute to a greater understanding of radiation transfer between the atmosphere and the hydrosphere, and enable improved models of wind-driven ocean-surface stress applicable to other remote sensing applications. In particular, we present lidar measurements of azimuthally anisotropic reflectance behavior and discuss the implications to current understanding of sea-surface optical properties. (C) 2002 Optical Society of America. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Alabama, Natl Space Sci & Technol Ctr, Huntsville, AL 35805 USA. NASA, Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM dtratt@jpl.nasa.gov RI Tratt, David/A-7884-2009; Hardesty, Robert/H-9844-2013 OI Tratt, David/0000-0002-3942-6848; NR 38 TC 7 Z9 7 U1 0 U2 2 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1559-128X EI 2155-3165 J9 APPL OPTICS JI Appl. Optics PD NOV 20 PY 2002 VL 41 IS 33 BP 6941 EP 6949 DI 10.1364/AO.41.006941 PG 9 WC Optics SC Optics GA 617VC UT WOS:000179380700003 PM 12463238 ER PT J AU Zhou, DK Smith, WL Li, J Howell, HB Cantwell, GW Larar, AM Knuteson, RO Tobin, DC Revercomb, HE Mango, SA AF Zhou, DK Smith, WL Li, J Howell, HB Cantwell, GW Larar, AM Knuteson, RO Tobin, DC Revercomb, HE Mango, SA TI Thermodynamic product retrieval methodology and validation for NAST-1 SO APPLIED OPTICS LA English DT Article ID ATMOSPHERIC-TEMPERATURE; ALGORITHM; PROFILES; SOUNDER; SATELLITES; RADIATION; AIRCRAFT; MOISTURE AB The National Polar-Orbiting Operational Environmental Satellite System (NPOESS) Airborne Sounder Testbed (NAST) consists of two passive collocated cross-track scanning instruments, an infrared interferometer (NAST-1) and a microwave radiometer (NAST-M), that fly onboard high-altitude aircraft such as the NASA ER-2 at an altitude near 20 km. NAST-I provides relatively high spectral resolution (0.25-cm(-1)) measurements in the 645-2700-cm(-1) spectral region with moderate spatial resolution (a linear resolution equal to 13% of the aircraft altitude at nadir) cross-track scanning. We report the methodology for retrieval of atmospheric temperature and composition profiles from NAST-I radiance spectra. The profiles were determined by use of a statistical eigenvector regression algorithm and improved, as needed, by use of a nonlinear physical retrieval algorithm. Several field campaigns conducted under varied meteorological conditions have provided the data needed to verify the accuracy of the spectral radiance, the retrieval algorithm, and the scanning capabilities of this instrumentation. Retrieval examples are presented to demonstrate the ability to reveal fine-scale horizontal features with relatively high vertical resolution. (C) 2002 Optical Society of America. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. Univ Wisconsin, Ctr Space Sci & Engn, Madison, WI 53706 USA. Utah State Univ, Space Dynam Lab, Logan, UT 84341 USA. Natl Polar Orbiting Operat Environm Satellite Sys, Silver Spring, MD 20910 USA. RP NASA, Langley Res Ctr, Hampton, VA 23681 USA. EM d.k.zhou@larc.nasa.gov RI Li, Jun/H-3579-2015 OI Li, Jun/0000-0001-5504-9627 NR 28 TC 52 Z9 53 U1 0 U2 3 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1559-128X EI 2155-3165 J9 APPL OPTICS JI Appl. Optics PD NOV 20 PY 2002 VL 41 IS 33 BP 6957 EP 6967 DI 10.1364/AO.41.006957 PG 11 WC Optics SC Optics GA 617VC UT WOS:000179380700005 PM 12463240 ER PT J AU Irion, FW Gunson, MR Toon, GC Chang, AY Eldering, A Mahieu, E Manney, GL Michelsen, HA Moyer, EJ Newchurch, MJ Osterman, GB Rinsland, CP Salawitch, RJ Sen, B Yung, YL Zander, R AF Irion, FW Gunson, MR Toon, GC Chang, AY Eldering, A Mahieu, E Manney, GL Michelsen, HA Moyer, EJ Newchurch, MJ Osterman, GB Rinsland, CP Salawitch, RJ Sen, B Yung, YL Zander, R TI Atmospheric Trace Molecule Spectroscopy (ATMOS) experiment version 3 data retrievals SO APPLIED OPTICS LA English DT Article ID SOLAR OCCULTATION SPECTRA; STRATOSPHERIC WATER-VAPOR; MIDDLE ATMOSPHERE; VOLCANIC AEROSOL; SPACE-SHUTTLE; NOVEMBER 1994; INSTRUMENTS; SATELLITE; EVOLUTION; AIRCRAFT AB Version 3 of the Atmospheric Trace Molecule Spectroscopy (ATMOS) experiment data set for some 30 trace and minor gas profiles is available. From the IR solar-absorption spectra measured during four Space Shuttle missions (in 1985, 1992, 1993, and 1994), profiles from more than 350 occultations were retrieved from the upper troposphere to the lower mesosphere. Previous results were unreliable for tropospheric retrievals, but with a new global-fitting algorithm profiles are reliably returned down to altitudes as low as 6.5 km (clouds permitting) and include notably improved retrievals of H2O, CO, and other species. Results for stratospheric water are more consistent across the ATMOS spectral filters and do not indicate a net consumption of H-2 in the upper stratosphere. A new sulfuric-acid aerosol product is described. An overview of ATMOS Version 3 processing is presented with a discussion of estimated uncertainties. Differences between these Version 3 and previously reported Version 2 ATMOS results are discussed. Retrievals are available at http://atmos.jpl.nasa.gov/atmos. (C) 2002 Optical Society of America. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Calif Los Angeles, Los Angeles, CA 90095 USA. Univ Liege, B-4000 Liege, Belgium. New Mexico Highlands Univ, Las Vegas, NM 87701 USA. Sandia Natl Labs, Livermore, CA 94551 USA. CALTECH, Pasadena, CA 91125 USA. Univ Alabama, Huntsville, AL 35899 USA. Natl Ctr Atmospher Res, Boulder, CO 80305 USA. NASA, Langley Res Ctr, Langley, VA 23681 USA. RP CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM bill.irion@jpl.nasa.gov RI Salawitch, Ross/B-4605-2009; OI Salawitch, Ross/0000-0001-8597-5832; Mahieu, Emmanuel/0000-0002-5251-0286 NR 45 TC 65 Z9 65 U1 1 U2 8 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 NOV 20 PY 2002 VL 41 IS 33 BP 6968 EP 6979 DI 10.1364/AO.41.006968 PG 12 WC Optics SC Optics GA 617VC UT WOS:000179380700006 PM 12463241 ER PT J AU Clerbaux, C Hadji-Lazaro, J Payan, S Camy-Peyret, C Wang, JX Edwards, DP Luo, M AF Clerbaux, C Hadji-Lazaro, J Payan, S Camy-Peyret, C Wang, JX Edwards, DP Luo, M TI Retrieval of CO from nadir remote-sensing measurements in the infrared by use of four different inversion algorithms SO APPLIED OPTICS LA English DT Article ID TROPOSPHERIC CARBON-MONOXIDE; CHEMICAL-TRANSPORT MODEL; SPECTRAL RADIANCES; RADIATIVE-TRANSFER; MOPITT INSTRUMENT; IMG RADIANCES; OCTOBER 1994; SATELLITE; OZONE; TEMPERATURE AB Four inversion schemes based on various retrieval approaches (digital gas correlation, nonlinear least squares, global fit adjustment, and neural networks) developed to retrieve CO from nadir radiances measured by such downward-looking satelliteborne instruments as the Measurement of Pollution in the Troposphere (MOPITT), the Tropospheric Emission Spectrometer (TES), and the Infrared Atmospheric Sounding Interferometer (IASI) instruments were compared both for simulated cases and for atmospheric spectra recorded by the Interferometric Monitor for Greenhouse Gases (IMG). The sensitivity of the retrieved CO total column amount to properties that may affect the inversion accuracy (noise, ancillary temperature profile, and water-vapor content) was investigated. The CO column amounts for the simulated radiance spectra agreed within 4%, whereas larger discrepancies were obtained when atmospheric spectra recorded by the IMG instrument were analyzed. The assumed vertical temperature profile is shown to be a critical parameter for accurate CO retrieval. The instrument's line shape was also identified as a possible cause of disagreement among the results provided by the groups of scientists who are participating in this study. (C) 2002 Optical Society of America. C1 Univ Paris 06, Serv Aeron, F-75252 Paris 5, France. Jet Prop Lab, Pasadena, CA 91109 USA. Natl Ctr Atmospher Res, Boulder, CO 80307 USA. Univ Paris 06, Lab Phys Mol & Applicat, F-75252 Paris 5, France. RP Univ Paris 06, Serv Aeron, 4 Pl Jussieu,BP102, F-75252 Paris 5, France. EM ccl@aero.jussieu.fr RI clerbaux, cathy/I-5478-2013 NR 58 TC 14 Z9 15 U1 0 U2 4 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1559-128X EI 2155-3165 J9 APPL OPTICS JI Appl. Optics PD NOV 20 PY 2002 VL 41 IS 33 BP 7068 EP 7078 DI 10.1364/AO.41.007068 PG 11 WC Optics SC Optics GA 617VC UT WOS:000179380700020 PM 12463254 ER PT J AU Liu, ZS Wu, D Liu, JT Zhang, KL Chen, WB Song, XQ Hair, JW She, CY AF Liu, ZS Wu, D Liu, JT Zhang, KL Chen, WB Song, XQ Hair, JW She, CY TI Low-altitude atmospheric wind measurement from the combined Mie and Rayleigh backscattering by Doppler lidar with an iodine filter SO APPLIED OPTICS LA English DT Article ID SPECTRAL-RESOLUTION LIDAR; EDGE TECHNIQUE; MIDDLE ATMOSPHERE; AEROSOL PROFILES AB This paper briefly discusses the mobile ground-based incoherent Doppler wind lidar system, with iodine filters as receiving frequency discriminators, developed by the Ocean Remote Sensing Laboratory, Ocean University of Qingdao, China. The presented result of wind profiles in October and November 2000, retrieved from the combined Mie and Rayleigh backscattering, is the first report to our knowledge of wind measurements in the troposphere by such a system, where the required independent measurement of aerosol-scattering ratio can also be performed. A second iodine vapor filter was used to lock the laser to absolute frequency reference for both wind and aerosol-scattering ratio measurements. Intercomparison experiments of the lidar wind profile measurements were performed with pilot balloons. Results showed that the standard deviation of wind speed and wind direction, for the 2-4 km altitude range, were 0.985 m/s and 17.9degrees, respectively. (C) 2002 Optical Society of America. C1 Ocean Univ Qingdao, Ocean Remote Sensing Inst, Minist Educ China, Ocean Remote Sensing Lab, Qingdao 266003, Peoples R China. NASA, Langley Res Ctr, Hampton, VA 23681 USA. Colorado State Univ, Dept Phys, Ft Collins, CO 80523 USA. RP Ocean Univ Qingdao, Ocean Remote Sensing Inst, Minist Educ China, Ocean Remote Sensing Lab, Qingdao 266003, Peoples R China. NR 21 TC 40 Z9 66 U1 5 U2 21 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 NOV 20 PY 2002 VL 41 IS 33 BP 7079 EP 7086 DI 10.1364/AO.41.007079 PG 8 WC Optics SC Optics GA 617VC UT WOS:000179380700021 PM 12463255 ER PT J AU Mishchenko, MI AF Mishchenko, MI TI Vector radiative transfer equation for arbitrarily shaped and arbitrarily oriented particles: a microphysical derivation from statistical electromagnetics SO APPLIED OPTICS LA English DT Article ID MULTIPLE-SCATTERING; LIGHT; ATMOSPHERE AB The concepts of statistical electromagnetics are used to derive the general radiative transfer equation (RTE) that describes multiple scattering of polarized light by sparse discrete random media consisting of arbitrarily shaped and arbitrarily oriented particles. The derivation starts with the volume integral and Lippmann-Schwinger equations for the electric field scattered by a fixed N-particle system and proceeds to the vector form of the Foldy-Lax equations and their approximate far-field version. I then assume that particle positions are completely random and derive the vector RTE by applying the Twersky approximation to the coherent electric field and the Twersky and ladder approximations to the coherency dyad of the diffuse field in the limit N --> infinity. The concluding section discusses the physical meaning of the quantities that enter the general vector RTE and the assumptions made in its derivation. C1 NASA, Goddard Inst Space Studies, New York, NY 10025 USA. RP NASA, Goddard Inst Space Studies, 2880 Broadway, New York, NY 10025 USA. EM crmim@giss.nasa.gov RI Mishchenko, Michael/D-4426-2012 NR 30 TC 76 Z9 76 U1 1 U2 2 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1559-128X EI 2155-3165 J9 APPL OPTICS JI Appl. Optics PD NOV 20 PY 2002 VL 41 IS 33 BP 7114 EP 7134 DI 10.1364/AO.41.007114 PG 21 WC Optics SC Optics GA 617VC UT WOS:000179380700025 PM 12463259 ER PT J AU Petry, D Bond, IH Bradbury, SM Buckley, JH Carter-Lewis, DA Cui, W Duke, C Perez, ID Falcone, A Fegan, DJ Fegan, SJ Finley, JP Gaidos, JA Gibbs, K Gammell, S Hall, J Hall, TA Hillas, AM Holder, J Horan, D Jordan, M Kertzman, M Kieda, D Kildea, J Knapp, J Kosack, K Krennrich, F LeBohec, S Moriarty, P Muller, D Nagai, TN Ong, R Page, M Pallassini, R Power-Mooney, B Quinn, J Reay, NW Reynolds, PT Rose, HJ Schroedter, M Sembroski, GH Sidwell, R Stanton, N Swordy, SP Vassiliev, VV Wakely, SP Walker, G Weekes, TC AF Petry, D Bond, IH Bradbury, SM Buckley, JH Carter-Lewis, DA Cui, W Duke, C Perez, ID Falcone, A Fegan, DJ Fegan, SJ Finley, JP Gaidos, JA Gibbs, K Gammell, S Hall, J Hall, TA Hillas, AM Holder, J Horan, D Jordan, M Kertzman, M Kieda, D Kildea, J Knapp, J Kosack, K Krennrich, F LeBohec, S Moriarty, P Muller, D Nagai, TN Ong, R Page, M Pallassini, R Power-Mooney, B Quinn, J Reay, NW Reynolds, PT Rose, HJ Schroedter, M Sembroski, GH Sidwell, R Stanton, N Swordy, SP Vassiliev, VV Wakely, SP Walker, G Weekes, TC TI The TeV spectrum of H1426+428 SO ASTROPHYSICAL JOURNAL LA English DT Article DE BL Lacertae objects : individual (H1426+428); gamma rays : observations ID RAY; OBJECTS AB The BL Lac object H1426+428 was recently detected as a high-energy gamma-ray source by the VERITAS collaboration (Horan et al.). We have reanalyzed the 2001 portion of the data used in the detection in order to examine the spectrum of H1426+428 above 250 GeV. We find that the time-averaged spectrum agrees with a power law of the shape (dF/dE) (E)=10(-7.31+/-0.15 stat +/-0.16 syst) E-3.50+/-0.35 stat +/-0.05 syst m(-2) s(-1) TeV-1. The statistical evidence from our data for emission above 2.5 TeV is 2.6 sigma. At the 95% confidence level, the integral flux of H1426+428 above 2.5 TeV is larger than 3% of the corresponding flux from the Crab Nebula. The spectrum is consistent with the (noncontemporaneous) measurement by Aharonian et al. both in shape and in normalization. Below 800 GeV, the data clearly favor a spectrum steeper than that of any other TeV blazar observed so far, indicating a difference in the processes involved either at the source or in the intervening space. C1 Iowa State Univ, Dept Phys & Astron, Ames, IA 50011 USA. Univ Leeds, Dept Phys, Leeds LS2 9JT, W Yorkshire, England. Washington Univ, Dept Phys, St Louis, MO 63130 USA. Purdue Univ, Dept Phys, W Lafayette, IN 47907 USA. Grinnell Coll, Dept Phys, Grinnell, IA 50112 USA. Natl Univ Ireland, Dept Phys, Dublin 4, Ireland. Harvard Smithsonian Ctr Astrophys, Fred Lawrence Whipple Observ, Amado, AZ 85645 USA. Univ Arizona, Dept Phys, Tucson, AZ 85721 USA. Univ Utah, High Energy Astrophys Inst, Salt Lake City, UT 84112 USA. Univ Arkansas, Dept Phys & Astron, Little Rock, AR 72204 USA. Depauw Univ, Dept Phys, Greencastle, IN 46135 USA. Galway Mayo Inst Technol, Sch Sci, Galway, Ireland. Univ Chicago, Enrico Fermi Inst, Chicago, IL 60637 USA. Univ Calif Los Angeles, Dept Phys, Los Angeles, CA 90095 USA. Kansas State Univ, Dept Phys, Manhattan, KS 66506 USA. Cork Inst Technol, Dept Phys, Cork, Ireland. RP Petry, D (reprint author), NASA, Goddard Space Flight Ctr, Code 661, Greenbelt, MD 20771 USA. RI Hall, Jeter/F-6108-2013; Hall, Jeter/E-9294-2015; OI Cui, Wei/0000-0002-6324-5772; Knapp, Johannes/0000-0003-1519-1383 NR 16 TC 49 Z9 49 U1 1 U2 4 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD NOV 20 PY 2002 VL 580 IS 1 BP 104 EP 109 DI 10.1086/343102 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 616ET UT WOS:000179291400012 ER PT J AU Jones, DL Wehrle, AE AF Jones, DL Wehrle, AE TI What happened to the NGC 6251 counterjet? SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; galaxies : active; galaxies : individual (NGC 6251); galaxies : jets; galaxies : nuclei; radio continuum : galaxies ID SPACE-TELESCOPE OBSERVATIONS; ACTIVE GALACTIC NUCLEI; ACCRETION DISK; CENTAURUS-A; RADIO JET; NGC-6251; PARSEC; GALAXIES; NGC-4261; NGC-1275 AB We have used the Very Long Baseline Array to produce a high dynamic range image of the nucleus of NGC 6251 at 1.6 GHz and snapshot images at 5.0, 8.4, and 15.3 GHz to search for emission from a parsec-scale counterjet. Previous VLBI images at 1.6 GHz have set a lower limit for the jet/counterjet brightness ratio near the core at about 80: 1, which is larger than expected, given the evidence that the radio axis is fairly close to the plane of the sky. A possible explanation is that the inner few parsecs of the counterjet are hidden by free-free absorption by ionized gas associated with an accretion disk or torus. This would be consistent with the nearly edge-on appearance of the arcsecond-scale dust disk seen in the center of NGC 6251 by Hubble Space Telescope (HST). We detect counterjet emission close to the core at 1.6 GHz, but not at the higher frequencies. Given that the optical depth of free-free absorption falls off more rapidly with increasing frequency than the optically thin synchrotron emission from a typical radio jet, this result implies that the absence of a detectable parsec-scale counterjet at high frequencies is not due to free-free absorption unless the density of ionized gas is extremely high and we have misidentified the core at 1.6 GHz. The most likely alternative is a large jet/counterjet brightness ratio caused by relativistic beaming, which in turn requires the inner radio axis to be closer to our line of sight than the orientation of the HST dust disk would suggest. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. CALTECH, Interferometry Sci Ctr, Pasadena, CA 91109 USA. RP Jones, DL (reprint author), CALTECH, Jet Prop Lab, Mail Code 238-332,4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 34 TC 11 Z9 11 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD NOV 20 PY 2002 VL 580 IS 1 BP 114 EP 121 DI 10.1086/343076 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 616ET UT WOS:000179291400014 ER PT J AU Naze, Y Hartwell, JM Stevens, IR Corcoran, MF Chu, YH Koenigsberger, G Moffat, AFJ Niemela, VS AF Naze, Y Hartwell, JM Stevens, IR Corcoran, MF Chu, YH Koenigsberger, G Moffat, AFJ Niemela, VS TI An X-ray investigation of the NGC 346 field in the Small Magellanic Cloud - I. The luminous blue variable HD 5980 and the NGC 346 cluster SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : star clusters; Magellanic Clouds; X-rays : individual (NGC 346, HD 5980); X-rays : stars ID COLLIDING WINDS; ETA-CARINAE; BINARY HD-5980; MASSIVE STARS; O-STAR; SMC; REMNANTS; EMISSION; GALAXY; HOT AB We present results from a Chandra observation of the NGC 346 cluster. This cluster contains numerous massive stars and is responsible for the ionization of N66, the most luminous H II region and the largest star formation region in the SMC. In this first paper we will focus on the characteristics of the main objects of the field. The NGC 346 cluster itself shows only relatively faint X-ray emission (with L-X(unabs) similar to 1.5x10(34) ergs s(-1)), tightly correlated with the core of the cluster. In the field also lies HD 5980, a luminous blue variable star in a binary (or possibly a triple) system that is detected for the first time at X-ray energies. The star is X-ray bright, with an unabsorbed luminosity of L-X(unabs) similar to 1.7x10(34) ergs s(-1), but needs to be monitored further to investigate its X-ray variability over a complete 19 day orbital cycle. The high X-ray luminosity may be associated either with colliding winds in the binary system or with the 1994 eruption. HD 5980 is surrounded by a region of diffuse X-ray emission, which is a supernova remnant. While it may be only a chance alignment with HD 5980, such a spatial coincidence may indicate that the remnant is indeed related to this peculiar massive star. C1 Univ Liege, Inst Astrophys & Geophys, B-4000 Liege, Belgium. Univ Birmingham, Sch Phys & Astron, Birmingham B15 2TT, W Midlands, England. NASA, Goddard Space Flight Ctr, Univ Space Res Assoc, High Energy Astrophys Sci Archive Res Ctr, Greenbelt, MD 20771 USA. Univ Illinois, Dept Astron, Urbana, IL 61801 USA. Univ Nacl Autonoma Mexico, Inst Astron, Mexico City 04510, DF, Mexico. Univ Montreal, Dept Phys, Montreal, PQ H3C 3J7, Canada. Univ Nacl La Plata, Fac Ciencias Astron & Geofis, La Plata, Argentina. RP Naze, Y (reprint author), Univ Liege, Inst Astrophys & Geophys, Allee 6 Aout 17,Bat B5C, B-4000 Liege, Belgium. OI Naze, Yael/0000-0003-4071-9346 NR 46 TC 35 Z9 35 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD NOV 20 PY 2002 VL 580 IS 1 BP 225 EP 234 DI 10.1086/343079 PN 1 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 616ET UT WOS:000179291400022 ER PT J AU Neufeld, DA Kaufman, MJ Goldsmith, PF Hollenbach, DJ Plume, R AF Neufeld, DA Kaufman, MJ Goldsmith, PF Hollenbach, DJ Plume, R TI Submillimeter Wave Astronomy Satellite and Arecibo observations of H2O and OH in a diffuse cloud along the line of sight to W51 SO ASTROPHYSICAL JOURNAL LA English DT Article DE ISM : abundances; ISM : clouds; ISM : molecules; molecular processes; radio lines : ISM; submillimeter ID DISSOCIATIVE RECOMBINATION; INTERSTELLAR WATER; ABSORPTION; REGIONS; PROFILES; VAPOR; RATES; H3O+; D3O+ AB Observations of W51 with the Submillimeter Wave Astronomy Satellite have yielded the first detection of water vapor in a diffuse molecular cloud. The water vapor lies in a foreground cloud that gives rise to an absorption feature at an LSR velocity of 6 km s(-1). The inferred water column density is 2.5x10(13) cm(-2). Observations with the Arecibo radio telescope of hydroxyl molecules at 10 positions in W51 imply an OH column density of 8x10(13) cm(-2) in the same diffuse cloud. The observed H2O/OH ratio of similar to0.3 is significantly larger than an upper limit derived previously from ultraviolet observations of the similar diffuse molecular cloud lying in front of HD 154368. The observed variation in H2O/OH likely points to the presence in one or both of these clouds of a warm (Tgreater than or similar to400 K) gas component in which neutral-neutral reactions are important sources of OH and/or H2O. C1 Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. San Jose State Univ, Dept Phys, San Jose, CA 95192 USA. Cornell Univ, Dept Astron, NAIC, Ithaca, NY 14853 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ Calgary, Dept Phys & Astron, Calgary, AB T2N 1N4, Canada. RP Neufeld, DA (reprint author), Johns Hopkins Univ, Dept Phys & Astron, 3400 N Charles St, Baltimore, MD 21218 USA. RI Goldsmith, Paul/H-3159-2016 NR 17 TC 37 Z9 37 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD NOV 20 PY 2002 VL 580 IS 1 BP 278 EP 284 DI 10.1086/343077 PN 1 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 616ET UT WOS:000179291400026 ER PT J AU Batalha, C Batalha, NM Alencar, SHP Lopes, DF Duarte, ES AF Batalha, C Batalha, NM Alencar, SHP Lopes, DF Duarte, ES TI Variability of southern T Tauri stars (VASTT). III. The continuum flux changes of the TW Hydrae bright spot SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; stars : individual (TW Hydrae); stars : pre-main-sequence; stars : variables : other ID DISK ACCRETION; ECHELLE SPECTRA; YOUNG STARS; BP-TAURI; X-RAY; EMISSION; LINE; PROFILE; ROTATION; CATALOG AB We have collected low-resolution spectrophotometric data of the classical T Tauri star TW Hya in an effort to detect and to follow the excess continuum emission (veiling) and the line changes at lambda < 5100 &ANGS;. The deveiled and calibrated flux distribution resembles that of a 30 Myr K7-M1 star of radius R = 0.8 R., mass M = 0.7 M., and log g = 4.5. The anticorrelation between the veiling (in the B band) and the observed Balmer jump found by previous authors, based on large samples of classical T Tauri stars, is confirmed in TW Hya. The line emission luminosities of the H, Ca II, and He I lines correlate with one another throughout the series, supporting the claims that the bulk of the line emission is formed in a single region or that their growth is controlled by a common mechanism. Surprisingly, the line emission fluxes do not correlate with the veiling at 4250 &ANGS; (B band). The line luminosities are, in general, less than 1% of the continuum luminosities. The veiling time series presents a cyclic behavior at 4.4 +/- 0.4 days. We collect all of the archival photometric data and analyze the B-band observations using different algorithms. We found solutions at either the 4.4 day timescale or one-half of this value. The data sets presenting the 2.2 day periodicity yield double-peaked light curves when folded at the 4.4 day timescale. We interpret the 4.4 day solution as the rotation period of the star. The veiling and the line emission measurements yield accretion luminosities for the series. We model the impacted area in the photosphere by an isothermal gas of a given density, temperature, and size (δ) whose parameters change as the star rotates. Estimates of the total spot area (δ), as a percentage of the stellar projected area, lie within the range 2.5 < delta < 6.0. The accretion luminosity of the impacted region does not remain constant throughout the series. The mass accretion rate ((M) over dot (acc)) that governs the luminosity varies within 1.0 x 10(-9) M. yr(-1) < (M) over dot (acc) < 4.8 x 10(-8) M. yr(-1). The spot luminosity and the associated (M) over dot (acc) are tightly correlated to the projected spot area, δ, and change their absolute value as the star spins. If most of the accretion is channeled to a single spot, its colatitude will be larger than 70&DEG;, indicating that the magnetic dipole is largely inclined. C1 CNPq, Observ Nacl, BR-20920400 Rio De Janeiro, Brazil. NASA, Ames Res Ctr, Planetary Syst Branch, Moffett Field, CA 94035 USA. Univ Sao Paulo, IAG, Dept Astron, BR-05508900 Sao Paulo, Brazil. RP Batalha, C (reprint author), CNPq, Observ Nacl, Rua Gen Jose Cristino 77, BR-20920400 Rio De Janeiro, Brazil. RI Alencar, Silvia/C-2803-2013 NR 54 TC 31 Z9 31 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD NOV 20 PY 2002 VL 580 IS 1 BP 343 EP 357 DI 10.1086/343110 PN 1 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 616ET UT WOS:000179291400031 ER PT J AU Harker, DE Wooden, DH Woodward, CE Lisse, CM AF Harker, DE Wooden, DH Woodward, CE Lisse, CM TI Grain properties of comet C/1995 O1 (Hale-Bopp) SO ASTROPHYSICAL JOURNAL LA English DT Article DE comets : general; comets : individual (C/1995 O1 Hale-Bopp); infrared : solar system ID INTERSTELLAR SILICATE MINERALOGY; INTERPLANETARY DUST PARTICLES; OPTICAL-PROPERTIES; INFRARED OBSERVATIONS; FAYALITIC OLIVINE; CARBON-MONOXIDE; SOLAR NEBULA; EVOLUTION; SPECTRA; STARS AB We present the analysis of 7.6-13.2 mum infrared (IR) spectrophotometry (R similar or equal to 250) of comet C/1995 O1 (Hale-Bopp), in conjunction with concurrent observations that extend the wavelength coverage of the spectral energy distribution from near- to far-infrared wavelengths. The observations include temporal epochs preperihelion (1996 October and 1997 February UT), near perihelion (1997 April UT), and postperihelion (1997 June UT). Through the modeling of the thermal emission from small, amorphous carbon grains and crystalline and amorphous silicate grains in Hale-Bopp's coma, we find that as the comet approached perihelion, the grain size distribution (the Hanner modified power law) steepened (from N = 3.4 preperihelion to N = 3.7 near and postperihelion), along with an increase in the fractal porosity of larger (greater than 1 mum) grains. The peak of the grain size distribution remained constant ( a(p) = 0.2 mum) at each epoch. We attribute the emergence of the 9.3 mum peak near perihelion to crystalline orthopyroxene grains released during epochs of high jet activity. Crystalline silicates (olivine and orthopyroxene) make up about 30% (by mass) of the sub-micronsized (less than or equal to1 mum) dust grains in Hale-Bopp's coma during each epoch. C1 NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA. Univ Minnesota, Dept Astron, Minneapolis, MN 55455 USA. Univ Maryland, Dept Astron, College Pk, MD 20742 USA. RP Harker, DE (reprint author), NASA, Ames Res Ctr, Div Space Sci, MS 245-3, Moffett Field, CA 94035 USA. RI Lisse, Carey/B-7772-2016; OI Lisse, Carey/0000-0002-9548-1526; Harker, David/0000-0001-6397-9082 NR 100 TC 90 Z9 90 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD NOV 20 PY 2002 VL 580 IS 1 BP 579 EP 597 DI 10.1086/343091 PN 1 PG 19 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 616ET UT WOS:000179291400054 ER PT J AU Kohno, M Koyama, K Hamaguchi, K AF Kohno, M Koyama, K Hamaguchi, K TI Chandra observations of high-mass young stellar objects in the monoceros R2 molecular cloud (vol 567, pg 423, 2002) SO ASTROPHYSICAL JOURNAL LA English DT Correction C1 Kyoto Univ, Grad Sch Sci, Dept Phys, Kyoto, Japan. NASA, Goddard Space Flight Ctr, High Energy Phys Lab, Greenbelt, MD 20771 USA. RP Kohno, M (reprint author), Kyoto Univ, Grad Sch Sci, Dept Phys, Kyoto, Japan. NR 1 TC 7 Z9 7 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD NOV 20 PY 2002 VL 580 IS 1 BP 626 EP 626 DI 10.1086/343117 PN 1 PG 1 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 616ET UT WOS:000179291400058 ER PT J AU Ofman, L Wang, TJ AF Ofman, L Wang, TJ TI Coronal loop oscillations observed by SUMER: Slow magnetosonic wave damping by thermal conduction SO ASTROPHYSICAL JOURNAL LA English DT Article DE MHD; Sun : activity; Sun : corona waves ID MAGNETOACOUSTIC WAVES; PLUMES; REGION; TRACE; EIT AB Recently, strongly damped Doppler shift oscillations of hot (T > 6 MK) coronal loops were observed with the Solar Ultraviolet Measurement of Emitted Radiation (SUMER) spectrometer on board the Solar and Heliospheric Observatory. The oscillations are interpreted as signatures of slow-mode magnetosonic waves excited impulsively in the loops. Using a one-dimensional MHD code, we model the oscillations and the damping of slow magnetosonic waves in a model coronal loop. We find that because of the high temperature of the loops, the large thermal conduction, which depends on temperature as T-2.5, leads to rapid damping of the slow waves on a timescale comparable to observations (5.5-29 minutes). The scaling of the dissipation time with period agrees well with SUMER observations of 35 cases in 17 events. We also find that the decay time due to compressive viscosity alone is an order of magnitude longer than the observed decay times. C1 Catholic Univ Amer, Dept Phys, Washington, DC 20064 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Max Planck Inst Aeron, D-37191 Katlenburg Lindau, Germany. RP Ofman, L (reprint author), Catholic Univ Amer, Dept Phys, Washington, DC 20064 USA. NR 31 TC 146 Z9 146 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD NOV 20 PY 2002 VL 580 IS 1 BP L85 EP L88 DI 10.1086/345548 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 616EU UT WOS:000179291500020 ER PT J AU Padoan, P Cambresy, L Langer, W AF Padoan, P Cambresy, L Langer, W TI Structure function scaling of a 2MASS extinction map of Taurus SO ASTROPHYSICAL JOURNAL LA English DT Article DE dust, extinction; ISM : kinematics and dynamics; turbulence ID FULLY-DEVELOPED TURBULENCE; MOLECULAR CLOUDS; SEARCH; DUST; LAW AB We compute the structure function scaling of a 2MASS extinction map of the Taurus molecular cloud complex. The scaling exponents of the structure functions of the extinction map follow Boldyrev's velocity structure function scaling of supersonic turbulence. This confirms our previous result based on a spectral map of (CO)-C-13 J = 1-0 covering the same region and suggests that supersonic turbulence is important in the fragmentation of this star-forming cloud. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Padoan, P (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 169-506, Pasadena, CA 91109 USA. OI Padoan, Paolo/0000-0002-5055-5800 NR 25 TC 40 Z9 40 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD NOV 20 PY 2002 VL 580 IS 1 BP L57 EP L60 DI 10.1086/345403 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 616EU UT WOS:000179291500013 ER PT J AU Begley, CM Kleis, SJ AF Begley, CM Kleis, SJ TI RWPV bioreactor mass transport: Earth-based and in microgravity SO BIOTECHNOLOGY AND BIOENGINEERING LA English DT Article DE bioreactor; mass transport; microgravity ID SIMULATED MICROGRAVITY; GROWTH AB Mass transport and mixing of perfused scalar quantities in the NASA Rotating Wall Perfused Vessel bioreactor are studied using numerical models of the flow field and scalar concentration field. Operating conditions typical of both microgravity and ground-based cell cultures are studied to determine the expected vessel performance for both flight and ground-based control experiments. Results are presented for the transport of oxygen with cell densities and consumption rates typical of colon cancer cells cultured in the RWPV. The transport and mixing characteristics are first investigated with a step change in the perfusion inlet concentration by computing the time histories of the time to exceed 10% inlet concentration. The effects of a uniform cell utilization rate are then investigated with time histories of the outlet concentration, volume average concentration, and volume fraction starved. It is found that the operating conditions used in microgravity produce results that are quite different then those for ground-based conditions. Mixing times for microgravity conditions are significantly shorter than those for ground-based operation. Increasing the differential rotation rates (microgravity) increases the mixing and transport, while increasing the mean rotation rate (ground-based) suppresses both. Increasing perfusion rates enhances mass transport for both microgravity and ground-based cases, however, for the present range of operating conditions, above 5-10 cc/min there are diminishing returns as much of the inlet fluid is transported directly to the perfusion exit. The results show that exit concentration is not a good indicator of the concentration distributions in the vessel. In microgravity conditions, the NASA RWPV bioreactor with the viscous pump has been shown to provide an environment that is well mixed. Even when operated near the theoretical minimum perfusion rates, only a small fraction of the volume provides less than the required oxygen levels. (C) 2002 Wiley Periodicals, Inc. C1 Univ Houston, Dept Mech Engn, Houston, TX 77204 USA. NASA, Lyndon B Johnson Space Ctr, United Space Alliance, Houston, TX 77058 USA. RP Kleis, SJ (reprint author), Univ Houston, Dept Mech Engn, Houston, TX 77204 USA. NR 16 TC 13 Z9 16 U1 2 U2 7 PU JOHN WILEY & SONS INC PI HOBOKEN PA 111 RIVER ST, HOBOKEN, NJ 07030 USA SN 0006-3592 J9 BIOTECHNOL BIOENG JI Biotechnol. Bioeng. PD NOV 20 PY 2002 VL 80 IS 4 BP 465 EP 476 DI 10.1002/bit.10395 PG 12 WC Biotechnology & Applied Microbiology SC Biotechnology & Applied Microbiology GA 604LW UT WOS:000178623600012 PM 12325155 ER PT J AU Christopher, SA Zhang, J Holben, BN Yang, SK AF Christopher, SA Zhang, J Holben, BN Yang, SK TI GOES-8 and NOAA-14 AVHRR retrieval of smoke aerosol optical thickness during SCAR-B SO INTERNATIONAL JOURNAL OF REMOTE SENSING LA English DT Article ID ENVIRONMENTAL SATELLITE; GOES-I; BIOMASS; BRAZIL; PARTICLES; CLOUDS; CALIBRATION; IMAGERS; TRACE AB Using the NOAA-14 1-km Advanced Very High Resolution Radiometer (AVHRR) and the Geostationary Operational Environmental Satellite (GOES-8) imager data, smoke aerosol optical thickness (tau) is retrieved over land during the Smoke, Clouds and Radiation-Brazil (SCAR-B) experiment in Brazil during August-September 1995. The satellite-retrieved tau values are then compared against ground-based sunphotometer derived tau values from the Aerosol Robotic Network (AERONET) program. Both the AVHRR and GOES-8 retrieved tau values are in excellent agreement with the AERONET derived tau values with linear correlation coefficients of 0.93. A single scattering albedo of 0.90 (at 0.67 mum) provides the best fit between the GOES-8 and AERONET tau values. The sensitivity of the retrieved tau to assumed surface albedo and aerosol single scattering albedo are also examined. A simple multi-spectral thresholding algorithm is used to separate smoke from other features from GOES-8 satellite imagery and regional maps of tau are provided. Our results show that the aerosol properties used in this paper are adequate to characterize biomass burning aerosols and can be used in studies that model the role of biomass burning on regional climate. C1 Univ Alabama Huntsville, Huntsville, AL 35806 USA. NASA, Goddard Space Flight Ctr, Biospher Sci Branch, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Atmospheres Lab, RDC,Climate Predict Ctr,NCEP, Greenbelt, MD 20771 USA. RP Christopher, SA (reprint author), Univ Alabama Huntsville, 320 Sparkman Dr, Huntsville, AL 35806 USA. RI Christopher, Sundar/E-6781-2011 NR 30 TC 21 Z9 22 U1 0 U2 1 PU TAYLOR & FRANCIS LTD PI ABINGDON PA 4 PARK SQUARE, MILTON PARK, ABINGDON OX14 4RN, OXON, ENGLAND SN 0143-1161 J9 INT J REMOTE SENS JI Int. J. Remote Sens. PD NOV 20 PY 2002 VL 23 IS 22 BP 4931 EP 4944 DI 10.1080/01431160110111045 PG 14 WC Remote Sensing; Imaging Science & Photographic Technology SC Remote Sensing; Imaging Science & Photographic Technology GA 611VF UT WOS:000179037900010 ER PT J AU Kumar, S Dang, TD Arnold, FE Bhattacharyya, AR Min, BG Zhang, XF Vaia, RA Park, C Adams, WW Hauge, RH Smalley, RE Ramesh, S Willis, PA AF Kumar, S Dang, TD Arnold, FE Bhattacharyya, AR Min, BG Zhang, XF Vaia, RA Park, C Adams, WW Hauge, RH Smalley, RE Ramesh, S Willis, PA TI Synthesis, structure, and properties of PBO/SWNT composites SO MACROMOLECULES LA English DT Article ID WALL CARBON NANOTUBES; COMPRESSIVE BEHAVIOR; FIBERS; BENZOBISOXAZOLE); MORPHOLOGY; NETWORK; PBO AB Poly(p-phenylene benzobisoxazole) (PBO) has been synthesized in the presence of single-wall carbon nanotubes (SWNTs) in poly(phosphoric acid) (PPA) using typical PBO polymerization conditions. PBO and PBO/SWNT lyotropic liquid crystalline solutions in PPA have been spun into fibers using dry-jet wet spinning. The tensile strength of the PBO/SWNT fiber containing 10 wt % SWNTs is about 50% higher than that of the control PBO fibers containing no SWNTs. The structure and morphology of these fibers have been studied. C1 Georgia Inst Technol, Sch Text & Fiber Engn, Atlanta, GA 30332 USA. Air Force Res Lab, Wright Patterson AFB, OH 45433 USA. NASA, Langley Res Ctr, ICASE, Hampton, VA 23681 USA. Rice Univ, Ctr Nanoscale Sci & Technol, Houston, TX 77005 USA. RP Kumar, S (reprint author), Georgia Inst Technol, Sch Text & Fiber Engn, Atlanta, GA 30332 USA. RI Hauge, Robert/A-7008-2011; Kumar, Satish/F-7308-2011; Adams, Wade/A-7305-2010; Willis, Peter/I-6621-2012 OI Hauge, Robert/0000-0002-3656-0152; NR 30 TC 378 Z9 391 U1 8 U2 90 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0024-9297 J9 MACROMOLECULES JI Macromolecules PD NOV 19 PY 2002 VL 35 IS 24 BP 9039 EP 9043 DI 10.1021/ma0205055 PG 5 WC Polymer Science SC Polymer Science GA 616HL UT WOS:000179298300021 ER PT J AU Carmichael, GR Streets, DG Calori, G Amann, M Jacobson, MZ Hansen, J Ueda, H AF Carmichael, GR Streets, DG Calori, G Amann, M Jacobson, MZ Hansen, J Ueda, H TI Changing trends in sulfur emissions in Asia: Implications for acid deposition, air pollution, and climate SO ENVIRONMENTAL SCIENCE & TECHNOLOGY LA English DT Article ID GREENHOUSE-GAS EMISSIONS; ENERGY-CONSUMPTION; DIOXIDE EMISSIONS; NORTH-AMERICA; BLACK CARBON; CHINA; NOX; TRANSPORT; ACIDIFICATION; PRECIPITATION AB In the early 1990s, it was projected that annual SO2 emissions in Asia might grow to 80-110 Tg yr(-1) by 2020. Based on new high-resolution estimates from 1975 to 2000, we calculate that SO2 emissions in Asia might grow only to 40-45 Tg yr(-1) by 2020. The main reason for this lower estimate is a decline of SO2 emissions from 1995 to 2000 in China, which emits about two-thirds of Asian SO2. The decline was due to a reduction in industrial coal use, a slow-down of the Chinese economy, and the closure of small and inefficient plants, among other reasons. One effect of the reduction in SO2 emissions in China has been a reduction in acid deposition not only in China but also in Japan. Reductions should also improve visibility and reduce health problems. SO2 emission reductions may increase global warming, but this warming effect could be partially offset by reductions in the emissions of black carbon. How SO2 emissions in the region change in the coming decades will depend on many competing factors (economic growth, pollution control laws, etc.). However a continuation of current trends would result in sulfur emissions lower than any IPCC forecasts. C1 Univ Iowa, Ctr Global & Reg Environm Res, Iowa City, IA 52242 USA. Argonne Natl Lab, Decis & Informat Sci Div, Argonne, IL 60439 USA. Int Inst Appl Syst Anal, A-2361 Laxenburg, Austria. Stanford Univ, Dept Civil & Environm Engn, Stanford, CA 94305 USA. NASA Goddard Inst Space Studies, New York, NY USA. Kyoto Univ, Disaster Prevent Res Inst, Kyoto 6110011, Japan. RP Carmichael, GR (reprint author), Univ Iowa, Ctr Global & Reg Environm Res, Iowa City, IA 52242 USA. OI Streets, David/0000-0002-0223-1350 NR 38 TC 67 Z9 70 U1 2 U2 25 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 NOV 15 PY 2002 VL 36 IS 22 BP 4707 EP 4713 DI 10.1021/es011509c PG 7 WC Engineering, Environmental; Environmental Sciences SC Engineering; Environmental Sciences & Ecology GA 617EN UT WOS:000179348500001 PM 12487289 ER PT J AU Liu, WT Xie, XS AF Liu, WT Xie, XS TI Double intertropical convergence zones - a new look using scatterometer SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID SEA-SURFACE TEMPERATURE; INTERANNUAL VARIABILITY; PACIFIC; WIND; ITCZ AB The high-resolution wind vectors observed by the space-based scatterometer QuikSCAT, from 1999 to 2002, show that the double intertropical convergence zones (ITCZ) exist in the Atlantic and the eastern Pacific oceans for most of the annual cycle, and are far more extensive than previously recognized. For most of the time, the southern ITCZ is weaker than the northern one. The stronger ITCZ occurs when the northerly trade winds meet the southerly trade winds over warm water, resulting in deep convection. The weaker ITCZ over cooler water is caused by the deceleration of the surface winds as they approach the cold upwelling water near the equator. Decreases in vertical mixing and increases in vertical wind shear in the atmospheric boundary layer are suggested to be the causes of the deceleration of the trade winds as they move from warmer to colder water. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Liu, WT (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 300-323, Pasadena, CA 91109 USA. NR 22 TC 3 Z9 3 U1 3 U2 8 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD NOV 15 PY 2002 VL 29 IS 22 AR 2072 DI 10.1029/2002GL015431 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 639FM UT WOS:000180617000029 ER PT J AU Murphy, N Smith, EJ Schwadron, NA AF Murphy, N Smith, EJ Schwadron, NA TI Strongly underwound magnetic fields in co-rotating rarefaction regions: Observations and Implications SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID SOLAR-WIND STREAM; ULYSSES; SUN AB Observations of the magnetic field orientation in co-rotating rarefaction regions (CRRs) reveals that the field can be significantly more radial than predicted by the Parker model. In particular, CRRs sampled by the Ulysses spacecraft beyond 4 AU from the sun often show average field orientations deviating by more than 30degrees from the expected Archimedian spiral and lasting many days. These observations are explained by a model combining footpoint motion between fast and slow solar wind streams at the source surface with the effects of velocity shear across coronal hole boundaries. C1 CALTECH, Jet Prop Lab, Div Earth & Space Sci, Pasadena, CA 91109 USA. SW Res Inst, San Antonio, TX USA. RP Murphy, N (reprint author), CALTECH, Jet Prop Lab, Div Earth & Space Sci, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 15 TC 37 Z9 37 U1 1 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD NOV 15 PY 2002 VL 29 IS 22 AR 2066 DI 10.1029/2002GL015164 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 639FM UT WOS:000180617000023 ER PT J AU Dailey, MN Cottrell, GW Padgett, C Adolphs, R AF Dailey, MN Cottrell, GW Padgett, C Adolphs, R TI EMPATH: A neural network that categorizes facial expressions SO JOURNAL OF COGNITIVE NEUROSCIENCE LA English DT Article ID OBJECT RECOGNITION; CIRCUMPLEX MODEL; PERCEPTION; EMOTION; CLASSIFICATION; FACES; ARCHITECTURE AB There are two competing theories of facial expression recognition. Some researchers have suggested that it is an example of "categorical perception." In this view, expression categories are considered to be discrete entities with sharp boundaries, and discrimination of nearby pairs of expressive faces is enhanced near those boundaries. Other researchers, however, suggest that facial expression perception is more graded and that facial expressions are best thought of as Points in a continuous, low-dimensional space, where, for instance, "surprise" expressions lie between "happiness" and "fear" expressions due to their perceptual similarity. In this article, we show that a simple yet biologically plausible neural network model, trained to classify facial expressions into six basic emotions, predicts data used to support both of these theories. Without any parameter tuning, the model matches a variety of psychological data on categorization, similarity, reaction times, discrimination, and recognition difficulty, both qualitatively and quantitatively. We thus explain many of the seemingly complex Psychological phenomena related to facial expression perception as natural consequences of the tasks' implementations in the brain. C1 Univ Calif San Diego, La Jolla, CA 92093 USA. Jet Prop Lab, Pasadena, CA USA. Univ Iowa, Iowa City, IA 52242 USA. RP Univ Calif San Diego, 9500 Gilman Dr, La Jolla, CA 92093 USA. EM gary@cs.ucsd.edu FU NIMH NIH HHS [MH57075] NR 53 TC 112 Z9 114 U1 8 U2 22 PU MIT PRESS PI CAMBRIDGE PA ONE ROGERS ST, CAMBRIDGE, MA 02142-1209 USA SN 0898-929X EI 1530-8898 J9 J COGNITIVE NEUROSCI JI J. Cogn. Neurosci. PD NOV 15 PY 2002 VL 14 IS 8 BP 1158 EP 1173 DI 10.1162/089892902760807177 PG 16 WC Neurosciences; Psychology, Experimental SC Neurosciences & Neurology; Psychology GA 613ZZ UT WOS:000179163500004 PM 12495523 ER PT J AU DiGiacomo, PM Hamner, WM Hamner, PP Caldeira, RMA AF DiGiacomo, PM Hamner, WM Hamner, PP Caldeira, RMA TI Phalaropes feeding at a coastal front in Santa Monica Bay, California SO JOURNAL OF MARINE SYSTEMS LA English DT Article; Proceedings Paper CT Meeting on Ocean Fronts held at the 2000 AGU Ocean Sciences Meeting CY JAN 24-28, 2000 CL SAN ANTONIO, TEXAS SP Amer Geophys Union, Amer Soc Limnol & Oceanog DE phalaropes; oceanic fronts; convergence zones; neuston; surface drifters; satellite sensing ID ANCHOVY ENGRAULIS-CAPENSIS; BERING SEA; SURFACE SLICKS; PRIBILOF ISLANDS; CURRENT SYSTEM; MONTEREY BAY; ZOOPLANKTON; CIRCULATION; ECOLOGY; LOBATUS AB The spinning behavior often exhibited by phalaropes when feeding at freshwater sites is rarely observed at sea. Instead, phalaropes are typically observed slowly swimming forward while foraging on marine neuston concentrated in surface convergence zones. Small-scale coastal ocean fronts, eddies and internal waves capable of generating such convergences are extremely common, albeit ephemeral, features in the Southern California Bight. This region is marked by a complex flow regime, resultant in part from its variable coastal morphology. We used satellite data (AVHRR) and in situ measurements (CTD, surface drifters) to describe and track a coastal front in Santa Monica Bay, California, centrally located in the Southern California Bight. A high number of Red-necked Phalaropes (Phalaropus lobatus) were associated with this feature over the course of several days. Neuston tows and gut content analyses revealed these phalaropes were primarily feeding on fish eggs and assorted debris that were abundant at the sea surface in this front. No phalaropes were observed spinning anywhere in the vicinity. Previously unpublished metabolic activity rates for phalaropes indicate that spinning is much more energetically expensive than is swimming at a comparable speed. Convergences associated with fronts (or eddies, internal waves, etc.) in the Southern California Bight apparently provide phalaropes with a rich, easily accessible and steady supply of food without having to resort to the energetically costly behavior of spinning. (C) 2002 Elsevier Science B.V. All rights reserved. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Calif Los Angeles, Dept Organism Biol Ecol & Evolut, Los Angeles, CA 90095 USA. RP DiGiacomo, PM (reprint author), CALTECH, Jet Prop Lab, MS 300-323,4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI DiGiacomo, Paul/F-5584-2010; Caldeira, Rui/J-9829-2013 OI DiGiacomo, Paul/0000-0003-4550-1899; Caldeira, Rui/0000-0001-8805-3016 NR 62 TC 9 Z9 11 U1 0 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0924-7963 J9 J MARINE SYST JI J. Mar. Syst. PD NOV 15 PY 2002 VL 37 IS 1-3 BP 199 EP 212 AR PII S0924-7963(02)00202-6 DI 10.1016/S0924-7963(02)00202-6 PG 14 WC Geosciences, Multidisciplinary; Marine & Freshwater Biology; Oceanography SC Geology; Marine & Freshwater Biology; Oceanography GA 617TW UT WOS:000179377800012 ER PT J AU Devia, VM Benner, DC Smith, MAH Rinsland, CP Mantz, AW AF Devia, VM Benner, DC Smith, MAH Rinsland, CP Mantz, AW TI Determination of self- and H-2-broadening and shift coefficients in the 2-0 band of (CO)-C-12-O-16 using a multispectrum fitting procedure SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Article DE CO; infrared spectra; Fourier transform infrared (FTIR) spectroscopy; spectral line shape ID DIODE-LASER MEASUREMENTS; 1ST OVERTONE BAND; CARBON-MONOXIDE; TEMPERATURE-RANGE; FUNDAMENTAL-BAND; LINE SHIFT; CO; HE; LINESHIFTS; STRENGTHS AB Self- and hydrogen-broadening coefficients and pressure-shift coefficients for the first overtone band transitions of (CO)-C-12-O-16 at room temperature have been determined through analysis of nine high-resolution (0.0055 cm(-1)) absorption spectra. These spectra were recorded using the 1-m Fourier transform spectrometer (FTS) at the McMath-Pierce facility of the National Solar Observatory on Kitt Peak, Arizona. Because of the short path length of the sample cell (10.0 cm), the volume mixing ratios of CO in hydrogen were relatively high, similar to18-22%, to achieve measurable absorption. These large volume-mixing ratios necessitated the simultaneous determination of the CO self-broadening and self-shift coefficients along with the hydrogen-broadening and hydrogen-induced shift coefficients. We have determined these coefficients at room temperature, along with line positions and absolute intensities, for the P(27) through R(27) (CO)-C-12-O-16 2-0 transitions by fitting the entire spectral interval from 4130 to 4345 cm(-1) in all nine spectra simultaneously using our multispectrum nonlinear least-squares procedure. Our intensity measurements are consistently low (1-6%) compared with the HITRAN values but the majority of the intensities are within 4% of the HITRAN values. The values of self-broadening coefficients vary from 0.0452 to 0.0862 cm(-1) atm(-1) at 296 K and those of hydrogen-broadening coefficient range between 0.0475 and 0.0795 cm(-1) atm(-1) at 296 K. All of our measured self- and hydrogen-shift coefficients are negative and range from -0.002 to -0.008 cm(-1) atm(-1). With the pressure and path length used in our study we did not find evidence of significant line mixing in either the self- or hydrogen-broadened spectra. This study represents the first high-resolution experimental determination of hydrogen-induced pressure broadening and pressure-shift coefficients in the 2-0 band of (CO)-C-12-O-16 at room temperature. (C) 2002 Elsevier Science Ltd. All rights reserved. C1 Coll William & Mary, Dept Phys, Williamsburg, VA 23187 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. Connecticut Coll, Dept Phys Astron & Geophys, New London, CT 06320 USA. RP Devia, VM (reprint author), Coll William & Mary, Dept Phys, Box 8795, Williamsburg, VA 23187 USA. NR 40 TC 15 Z9 15 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0022-4073 J9 J QUANT SPECTROSC RA JI J. Quant. Spectrosc. Radiat. Transf. PD NOV 15 PY 2002 VL 75 IS 4 BP 455 EP 471 AR PII S0022-4073(02)00023-7 DI 10.1016/S0022-4073(02)00023-7 PG 17 WC Optics; Spectroscopy SC Optics; Spectroscopy GA 586ZG UT WOS:000177615600003 ER PT J AU Hazen, RM Boctor, N Brandes, JA Cody, GD Hemley, RJ Sharma, A Yoder, HS AF Hazen, RM Boctor, N Brandes, JA Cody, GD Hemley, RJ Sharma, A Yoder, HS TI High pressure and the origin of life SO JOURNAL OF PHYSICS-CONDENSED MATTER LA English DT Article ID ORGANIC-REACTIONS; DEEP; SEA; BIOSPHERE; WATER; BACTERIA; HOT; TEMPERATURES; SEDIMENTS; STABILITY AB Three lines of experimental research suggest that high pressure may have played a significant role in the origin of life. Discoveries of abundant life in high-pressure environments, including deep oceans, hydrothermal vents, and crustal rocks, point to the adaptation of life to a variety of aqueous habitats. Cultures of microbes at high pressure display both barotolerant and barophilic behaviour. And studies of high-pressure hydrothermal organic synthesis reveal unexpectedly facile reaction mechanisms for the production of a variety of requisite biomolecules. C1 Geophys Lab, Washington, DC 20015 USA. NASA, Astrobiol Inst, Washington, DC 20015 USA. RP Hazen, RM (reprint author), Geophys Lab, 5251 Broad Branch Rd NW, Washington, DC 20015 USA. NR 54 TC 19 Z9 19 U1 3 U2 21 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 NOV 11 PY 2002 VL 14 IS 44 BP 11489 EP 11494 AR PII S0953-8984(02)38337-1 DI 10.1088/0953-8984/14/44/504 PG 6 WC Physics, Condensed Matter SC Physics GA 620PL UT WOS:000179541700204 ER PT J AU Colombo, JFA Morrell, NI Rauw, G Corcoran, MF Niemela, VS Sana, H AF Colombo, JFA Morrell, NI Rauw, G Corcoran, MF Niemela, VS Sana, H TI Optical spectroscopy of X-Mega targets - IV. CPD-59 degrees 2636: a new O-type multiple system in the Carina Nebula SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE binaries : general; stars : early-type; stars : fundamental parameters; stars : individual : CPD 59 degrees 2636; open clusters and associations : individual : Trumpler 16; X-rays : stars ID SPECTRAL CLASSIFICATION; STELLAR CONTENT; STARS; BINARY; WINDS AB High-resolution optical spectroscopy of CPD -59degrees2636, one of the O-type stars in the open cluster Trumpler 16 in the Carina Nebula, reveals this object to be a multiple system displaying triple lines which we label as components A, B and C of spectral types O7 V, O8 V and O9 V, respectively. From our radial velocity measurements we find that the components A and B form a close binary with a period of 3.6284 d, and we obtain the first circular radial velocity orbit for this system with semi-amplitudes of 184 and 192 km s(-1), leading to minimum masses of 10.1 and 9.7 M-.. We find that the component C is a single lined binary with a period of 5.034 d and semi-amplitude of 48 km s(-1). We also analyse the X-ray radiation from CPD -59degrees2636, finding neither appreciable overluminosity nor phase-related X-ray flux variations. C1 Natl Univ La Plata, Fac Ciencias Astron & Geofis, RA-1900 La Plata, Argentina. State Univ Liege, Inst Astrophys, B-4000 Liege, Sart Tilman, Belgium. Univ Space Res Assoc, Seabrook, MD 20771 USA. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Colombo, JFA (reprint author), Natl Univ La Plata, Fac Ciencias Astron & Geofis, Paseo Bosque S-N, RA-1900 La Plata, Argentina. RI Sana, Hugues/B-2664-2013 OI Sana, Hugues/0000-0001-6656-4130 NR 41 TC 11 Z9 11 U1 0 U2 0 PU BLACKWELL PUBLISHING LTD PI OXFORD PA 9600 GARSINGTON RD, OXFORD OX4 2DG, OXON, ENGLAND SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD NOV 11 PY 2002 VL 336 IS 4 BP 1099 EP 1108 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 610VC UT WOS:000178981200007 ER PT J AU Waddington, I Windhorst, RA Cohen, SH Dunlop, JS Peacock, JA Jimenez, R McLure, RJ Bunker, AJ Spinrad, H Dey, A Stern, D AF Waddington, I Windhorst, RA Cohen, SH Dunlop, JS Peacock, JA Jimenez, R McLure, RJ Bunker, AJ Spinrad, H Dey, A Stern, D TI Old elliptical galaxies at z similar to 1.5 and the Kormendy relation SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE galaxies : active; galaxies : elliptical and lenticular, cD; galaxies : evolution; galaxies : individual : LBDS 53W069; galaxies : individual : LBDS 53W091 ID RADIO-QUIET QUASARS; COLOR GRADIENTS; SOURCE IDENTIFICATIONS; INFRARED OBSERVATIONS; STELLAR POPULATIONS; SPECTRAL EVOLUTION; SURFACE PHOTOMETRY; DISTANT CLUSTERS; LBDS 53W091; REDSHIFT AB Deep spectroscopy of the two Leiden-Berkeley Deep Survey mJy radio galaxies LBDS 53W069 and 53W091 has previously shown them to have old (greater than or similar to3 Gyr) stellar populations at z similar or equal to 1.5. Here we present the results of Hubble Space Telescope (HST) observations with the Wide Field and Planetary Camera 2 (WFPC2) in F814W and with the Near-Infrared Camera and Multi-Object Spectrograph (NICMOS) in F110W. We find that 53W069 has a de Vaucouleurs r(1/4) profile in both the F814W and F110W data, with a mean effective radius of 0.30 +/- 0.06 arcsec (2.7 +/- 0.5 kpc). The rest-frame U - B colour gradient is consistent with that of present-day ellipticals, requiring a stellar population of supersolar (3 Z.) metallicity that formed on a very short time-scale at high redshift (z > 5). 53W091 has a regular r(1/4) profile in F110W with an effective radius of 0.32 +/- 0.08 arcsec (2.9 +/- 0.7 kpc). The F814W profile is more extended and is consistent with the presence of a blue exponential disc that contributes 20 +/- 10 per cent of the flux within r(e). We find a rest- frame U - B colour gradient that is significantly larger than that observed in field ellipticals at z less than or equal to 1, implying a stellar population of mixed metallicity (1-3 Z.) that formed in a high-redshift rapid burst. We have compared these two LBDS radio galaxies with the Kormendy relations of ten 3CR radio galaxies at z similar or equal to 0.8 and a sample of cluster ellipticals at z similar to 0.4. The LBDS galaxies follow the Kormendy relation for the more radio-luminous 3CR galaxies, assuming passive evolution of their stellar populations, although they are smaller than the 3CR galaxies whose mean effective radius is 12 kpc. Their sizes and radio luminosities are consistent with scaling relations applied to the 3CR galaxies, in which both radio power and effective radius scale with galaxy mass. Compared with the sample of cluster ellipticals, 53W069 and 53W091 lie well within the scatter of the Kormendy relation. We conclude that the hosts of these millijansky radio sources at z similar or equal to 1.5 are passively evolving elliptical galaxies that will evolve into ordinary L* ellipticals by the present day. C1 Univ Bristol, HH Wills Phys Lab, Dept Phys, Bristol BS8 1TL, Avon, England. Arizona State Univ, Dept Phys & Astron, Tempe, AZ 85287 USA. Univ Edinburgh, Royal Observ, Astron Inst, Edinburgh EH9 3HJ, Midlothian, Scotland. Rutgers State Univ, Dept Phys & Astron, Piscataway, NJ 08854 USA. Univ Oxford, Nucl & Astrophys Lab, Oxford OX1 3RH, England. Univ Cambridge, Inst Astron, Cambridge CB3 0HA, England. Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA. Kitt Peak Natl Observ, Natl Opt Astron Observ, Tucson, AZ 85726 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Waddington, I (reprint author), Univ Bristol, HH Wills Phys Lab, Dept Phys, Tyndall Ave, Bristol BS8 1TL, Avon, England. OI Jimenez, Raul/0000-0002-3370-3103 NR 66 TC 16 Z9 16 U1 0 U2 2 PU BLACKWELL PUBLISHING LTD PI OXFORD PA 9600 GARSINGTON RD, OXFORD OX4 2DG, OXON, ENGLAND SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD NOV 11 PY 2002 VL 336 IS 4 BP 1342 EP 1350 DI 10.1046/j.1365-8711.2002.05870.x PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 610VC UT WOS:000178981200032 ER PT J AU Zbilut, JR Dixon, DD Zak, M AF Zbilut, JR Dixon, DD Zak, M TI Detecting singularities of piecewise deterministic (terminal) dynamics in experimental data SO PHYSICS LETTERS A LA English DT Article DE singularity; Liapunov exponent; recurrence quantification; non-linear dynamics; chaos; determinism; non-Lipschitz dynamics ID PHYSIOLOGICAL SINGULARITIES; RECURRENCE PLOTS; EQUATIONS; MOTION; NOISE AB Piecewise deterministic (terminal) dynamics with singularities have been suggested as a model for many physical and biological systems. A difficulty, however, has been their detection in experimental situations. A method developed from recurrence-based Liapunov exponents is suggested. Practical implications for the detection of such dynamics is discussed. (C) 2002 Elsevier Science B.V. All rights reserved. C1 Rush Univ, Dept Physiol & Mol Biophys, Chicago, IL 60612 USA. Univ Calif Riverside, Inst Geophys & Planetary Phys, Riverside, CA 92521 USA. CALTECH, Jet Prop Lab, Ultra Comp Grp, Pasadena, CA 91109 USA. RP Zbilut, JR (reprint author), Rush Univ, Dept Physiol & Mol Biophys, 1653 W Congress, Chicago, IL 60612 USA. NR 12 TC 12 Z9 12 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0375-9601 J9 PHYS LETT A JI Phys. Lett. A PD NOV 11 PY 2002 VL 304 IS 3-4 BP 95 EP 101 AR PII S0375-9601(02)01321-X DI 10.1016/S0375-9601(02)01321-X PG 7 WC Physics, Multidisciplinary SC Physics GA 618PD UT WOS:000179425700006 ER PT J AU Xu, H Kahn, SM Peterson, JR Behar, E Paerels, FBS Mushotzky, RF Jernigan, JG Brinkman, AC Makishima, K AF Xu, H Kahn, SM Peterson, JR Behar, E Paerels, FBS Mushotzky, RF Jernigan, JG Brinkman, AC Makishima, K TI High-resolution observations of the elliptical galaxy NGC 4636 with the reflection grating spectrometer on board XMM-Newton SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : elliptical and lenticular, cD; galaxies : individual (NGC 4636); galaxies : ISM; X-rays : galaxies ID X-RAY-EMISSION; COOLING FLOW; FE-XVII; ASCA OBSERVATION; ABUNDANCES; NGC-4636; CLUSTERS; LUMINOSITY; ENRICHMENT; INTENSITY AB We present the first high spectral resolution X-ray observation of the giant elliptical galaxy NGC 4636, obtained with the reflection grating spectrometer on board the XMM-Newton Observatory. The resulting spectrum contains a wealth of emission lines from various charge states of oxygen, neon, magnesium, and iron. Examination of the cross-dispersion profiles of several of these lines provides clear, unambiguous evidence of resonance scattering by the highest oscillator strength lines, as well as a weak temperature gradient in the inner regions of the interstellar medium. We invoke a sophisticated new Monte Carlo technique that allows us to properly account for these effects in performing quantitative fits to the spectrum. Our spectral fits are not subject to many of the systematics that have plagued earlier investigations. The derived metal abundances are higher than have usually been inferred from prior, lower spectral resolution observations of this source, but are still incompatible with conventional chemical-enrichment models of elliptical galaxies. In addition, our data are incompatible with standard cooling-flow models for this system; our derived upper limit to the mass deposition rate is below the predicted value by a factor of 3-5. C1 Columbia Univ, Astrophys Lab, New York, NY 10027 USA. Shanghai Jiao Tong Univ, Dept Phys, Shanghai 200030, Peoples R China. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. SRON, Natl Inst Space Res, NL-3584 CA Utrecht, Netherlands. Univ Tokyo, Dept Phys, Bunkyo Ku, Tokyo 1130033, Japan. RP Columbia Univ, Astrophys Lab, 550 W 120th St, New York, NY 10027 USA. NR 40 TC 131 Z9 132 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X EI 1538-4357 J9 ASTROPHYS J JI Astrophys. J. PD NOV 10 PY 2002 VL 579 IS 2 BP 600 EP 606 DI 10.1086/342828 PN 1 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 612EZ UT WOS:000179062700013 ER PT J AU Wang, L Wheeler, JC Hoflich, P Khokhlov, A Baade, D Branch, D Challis, P Filippenko, AV Fransson, C Garnavich, P Kirshner, RP Lundqvist, P McCray, R Panagia, N Pun, CSJ Phillips, MM Sonneborn, G Suntzeff, NB AF Wang, L Wheeler, JC Hoflich, P Khokhlov, A Baade, D Branch, D Challis, P Filippenko, AV Fransson, C Garnavich, P Kirshner, RP Lundqvist, P McCray, R Panagia, N Pun, CSJ Phillips, MM Sonneborn, G Suntzeff, NB TI The axisymmetric ejecta of supernova 1987A SO ASTROPHYSICAL JOURNAL LA English DT Article DE supernova remnants; supernovae : individual (SN 1987A) ID GAMMA-RAY BURSTS; SN 1987A; NEUTRINO RADIATION; SN-1987A; SPECTROPOLARIMETRY; POLARIZATION; EXPLOSIONS; EMISSION; LINE; JET AB Extensive early observations proved that the ejecta of supernova 1987A (SN 1987A) are aspherical. The most important of these early observations include (1) the "Bochum event" that revealed small-scale spectroscopic structure indicating chemical inhomogeneities of the ejecta, (2) spectropolarimetry that showed deviations from spherical symmetry, and ( 3) speckle observations that revealed both the asymmetry of the ejecta and the "mystery spot" manifested as a secondary source off center from the bulk of the supernova ejecta. Fifteen years after the supernova explosion, the Hubble Space Telescope has resolved the rapidly expanding ejecta. The late-time images and spectroscopy provide a geometrical picture that is consistent with early observations and suggests a highly structured, axially symmetric geometry. We present here a new synthesis of the old and new data. We show that the Bochum event, presumably a clump of Ni-56, and the late-time image, the locus of excitation by Ti-44, are most naturally accounted for by sharing a common position angle of about 14degrees the same as the mystery spot and early speckle data on the ejecta, and that they are both oriented along the axis of the inner circumstellar ring at 45degrees to the plane of the sky. We also demonstrate that the polarization represents a prolate geometry with the same position angle and axis as the early speckle data and the late-time image, and hence that the geometry has been fixed in time and throughout the ejecta. The Bochum event and the Doppler kinematics of the [Ca II]/[O II] emission in spatially resolved Hubble Space Telescope spectra of the ejecta can be consistently integrated into this geometry. The radioactive clump is deduced to fall approximately along the axis of the inner circumstellar ring and therefore to be redshifted in the north, whereas the [Ca II]/[O II] 7300 Angstrom emission is redshifted in the south. We present a jet-induced model for the explosion and argue that such a model can account for many of the observed asymmetries. In the jet models, the oxygen and calcium are not expected to be distributed along the jet but primarily in an expanding torus that shares the plane and northern blue shift of the inner circumstellar ring. C1 Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. Univ Texas, Dept Astron, Austin, TX 78712 USA. USN, Computat Phys & Fluid Dynam Lab, Res Lab, Washington, DC 20375 USA. European So Observ, D-85748 Garching, Germany. Univ Oklahoma, Dept Phys & Astron, Norman, OK 73019 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA. Stockholm Observ, AlbaNova, Dept Astron, SE-10691 Stockholm, Sweden. Univ Notre Dame, Dept Phys, Notre Dame, IN 46556 USA. Univ Colorado, Joint Inst Lab Astrophys, Boulder, CO 80309 USA. Space Telescope Sci Inst, Baltimore, MD 21218 USA. ESA, Dept Space Sci, F-75738 Paris 15, France. NASA, Goddard Space Flight Ctr, Lab Astron & Space Phys, Greenbelt, MD 20771 USA. Carnegie Observ, Campanas Observ, La Serena, Chile. Natl Opt Astron Observ, Cerro Tololo Interamer Observ, La Serena, Chile. RP Wang, L (reprint author), Univ Calif Berkeley, Lawrence Berkeley Lab, 50-232,1 Cyclotron Rd, Berkeley, CA 94720 USA. RI Sonneborn, George/D-5255-2012 NR 59 TC 132 Z9 134 U1 0 U2 3 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD NOV 10 PY 2002 VL 579 IS 2 BP 671 EP 677 DI 10.1086/342824 PN 1 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 612EZ UT WOS:000179062700019 ER PT J AU Cannizzo, JK Gehrels, N Mattei, JA AF Cannizzo, JK Gehrels, N Mattei, JA TI The 1985 October long outburst of U Geminorum: Revealing the viscous timescale in long orbital period dwarf novae SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; binaries : close; novae, cataclysmic variables; stars : individual (U Geminorum) ID SS-CYGNI; ACCRETION DISKS; LIGHT CURVES; TERM BEHAVIOR; WHITE-DWARF; SPECTROSCOPY; DELAY AB We examine the AAVSO light curve of U Gem from 1908 to 2002, with particular focus on the 1985 October outburst. This outburst was longer than any other seen in U Gem by about a factor of 2 and appears to be unique among all dwarf nova outbursts seen in systems with orbital periods longer than 3 hr in that one can measure the decay timescale during the initial slow decay. This rate is similar to26 +/- 6 days mag(-1). Using estimates of the rate of accretion during outburst taken from Froning et al., one can show that similar to10(24) g of gas was accreted onto the white dwarf during the outburst, which constrains the surface density in the outer accretion disk to be similar to600 g cm(-2). The observed timescale for decay is consistent with that expected in U Gem, given its orbital period and disk mass at the time the outburst began. The data are not of sufficient quality to be able to ascertain a deviation from exponentiality in the decay light curve ( as in the SU UMa stars superoutbursts). When coupled with the viscous time inferred from the (short orbital period) SU UMa stars, the U Gem viscous timescale lends support to the standard model in which the decays in dwarf novae can either be viscous or thermal, with the ratio between them being roughly h/r, where h is the vertical pressure scale height in the disk. Indeed, dwarf novae are the only systems for which one can be reasonably certain of the identification of "viscous" and "thermal" decays. C1 NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. Amer Assoc Variable Star Observers, Cambridge, MA 02138 USA. Univ Maryland Baltimore Cty, Baltimore, MD 21228 USA. RP Cannizzo, JK (reprint author), NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Code 661, Greenbelt, MD 20771 USA. RI Gehrels, Neil/D-2971-2012 NR 29 TC 13 Z9 13 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD NOV 10 PY 2002 VL 579 IS 2 BP 760 EP 763 DI 10.1086/342843 PN 1 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 612EZ UT WOS:000179062700029 ER PT J AU Brown, TM Heap, SR Hubeny, I Lanz, T Lindler, D AF Brown, TM Heap, SR Hubeny, I Lanz, T Lindler, D TI Isolating clusters with Wolf-rayet stars in I Zw 18 SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : starburst; galaxies : stellar content; stars : Wolf Rayet; ultraviolet : galaxies ID TELESCOPE IMAGING SPECTROGRAPH; I-ZW-18; GALAXIES; MODELS; POPULATION; BLUE AB We present UV images and spectra of the starburst galaxy I Zw 18, taken with the Space Telescope Imaging Spectrograph. The high spatial resolution of these data allows us to isolate clusters containing Wolf-Rayet stars of the subtype WC. Our far-UV spectra clearly show C IV lambdalambda1548, 1551 and He II lambda1640 emission of WC stars in two clusters: one within the bright (northwest) half of I Zw 18 and one on the outskirts of this region. The latter spectrum is unusual because the C IV is seen only in emission, indicating a spectrum dominated by WC stars. These data also demonstrate that the H I column in I Zw 18 is strongly peaked in the fainter (southeast) half of I Zw 18, with a column depth far larger than that reported in previous analyses. C1 Space Telescope Sci Inst, Baltimore, MD 21218 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Brown, TM (reprint author), Space Telescope Sci Inst, 3700 San Martin Dr, Baltimore, MD 21218 USA. OI Brown, Thomas/0000-0002-1793-9968 NR 27 TC 26 Z9 26 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD NOV 10 PY 2002 VL 579 IS 2 BP L75 EP L78 DI 10.1086/345336 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 612FG UT WOS:000179063400006 ER PT J AU Chiar, JE Peeters, E Tielens, AGGM AF Chiar, JE Peeters, E Tielens, AGGM TI The infrared emission features in the spectrum of the Wolf-Rayet star WR 48a SO ASTROPHYSICAL JOURNAL LA English DT Article DE circumstellar matter; stars : individual (WR 48a); stars : Wolf-Rayet ID GAS-PHASE; INTERSTELLAR EXTINCTION; AMORPHOUS-CARBON; DUST FORMATION; NEBULAE; CIRCUMSTELLAR; ENVIRONMENTS; FULLERENES; CLUSTERS; BANDS AB We present the first detection of unidentified infrared (UIR) emission features at similar to6.4 and 7.9 mum in the spectrum of the dusty WC8 Wolf-Rayet star WR 48a. Based on the H-deficient nature of WC stars, we attribute the emission features to large carbonaceous molecules or amorphous carbon dust grains in the circumstellar environment of WR 48a. The 6.4 mum feature resembles the emission feature seen toward H-deficient planetary nebulae (PNe), while the 7.9 mum profile resembles that of some PNe with H-deficient WC10 central stars. These similarities point toward a similar origin of the dust in these H-deficient environments and highlights the apparent sensitivity of the UIR bands to physical conditions. In the case of WR 48a and the [WC10] PNe, shock processing may play a major role in dust formation. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. SETI Inst, Mt View, CA 94043 USA. SRON Natl Inst Space Res, Kapteyn Astron Inst, NL-9700 AV Groningen, Netherlands. RP Chiar, JE (reprint author), NASA, Ames Res Ctr, Mail Stop 245-3, Moffett Field, CA 94035 USA. NR 32 TC 10 Z9 10 U1 1 U2 3 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD NOV 10 PY 2002 VL 579 IS 2 BP L91 EP L94 DI 10.1086/345316 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 612FG UT WOS:000179063400010 ER PT J AU Kashlinsky, A Odenwald, S Mather, J Skrutskie, MF Cutri, RM AF Kashlinsky, A Odenwald, S Mather, J Skrutskie, MF Cutri, RM TI Detection of small-scale fluctuations in the near-infrared cosmic infrared background from long-exposure 2MASS fields SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmology : observations; diffuse radiation; galaxies : evolution; large scale structure of universe ID COBE DIRBE MAPS; EVOLUTION; GALAXIES; LIGHT AB We report first results for the cosmic infrared background (CIB) fluctuations at 1.25, 1.65, and 2.17 mum obtained from long exposures constructed from Two Micron All Sky Survey standard star fields. We have co-added and analyzed scans from one such field with a total exposure time greater than 1 hr and removed sources and other artifacts. The stars and galaxies were clipped out to K-s similar or equal to 19 mag, leaving only high-z galaxies (or possibly local low surface brightness systems). The angular power spectrum of the remaining diffuse emission on scales from a few arcseconds to a few arcminutes has a power-law slope consistent with emission produced by clustered galaxies. The noise (and residual artifacts) contribution to the signal is small, and the colors of the signal are very different from Galactic stars or airglow. We therefore identify the signal as CIB fluctuations from the faint unresolved galaxies. We show that the present-day galaxies with no evolution would produce a significant deficit in the observed CIB fluctuations. Thus, the dominant contribution to the observed signal must come from high z and may indicate high rates of star formation at those epochs. C1 Sci Syst & Applicat Inc, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Virginia, Dept Astron, Charlottesville, VA 22903 USA. CALTECH, Ctr Infrared Proc & Anal, Pasadena, CA 91125 USA. RP Sci Syst & Applicat Inc, Goddard Space Flight Ctr, Code 685, Greenbelt, MD 20771 USA. EM kashlinsky@stars.gsfc.nasa.gov NR 28 TC 36 Z9 36 U1 0 U2 2 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X EI 1538-4357 J9 ASTROPHYS J JI Astrophys. J. PD NOV 10 PY 2002 VL 579 IS 2 BP L53 EP L57 DI 10.1086/345335 PN 2 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 612FG UT WOS:000179063400001 ER PT J AU Tremblay, B Manceron, L Gutsev, GL Andrews, L Partridge, H AF Tremblay, B Manceron, L Gutsev, GL Andrews, L Partridge, H TI Experimental and theoretical infrared spectra of Co2CO SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID DENSITY-FUNCTIONAL CALCULATIONS; SINGLE-WALLED NANOTUBES; GAUSSIAN-BASIS SETS; CARBON NANOTUBES; METAL-CLUSTERS; SOLID ARGON; COBALT; ANIONS; CO; MONOXIDE AB Matrix infrared spectra of Co2CO were obtained from cobalt vapors condensed with different isotopically substituted mixtures of carbon monoxide diluted in argon at 10 K. New bands at 1953.3, 488.7, 357.9, and 270.9 cm(-1) are assigned to the nu(C-O), nu(M-CO), nu(M-C-O), and nu(M-M) fundamentals, respectively. Computations performed using density functional theory with the generalized gradient approximation (DFT-GGA) for the exchange-correlation potential predict the lowest energy state of Co2CO to be (5)A" with the angle Co-Co-C of 116degrees. Our DFT-GGA vibrational frequencies of this state agree with the experimental frequencies extremely well-within 15 cm(-1). Our estimate for the Co-2-CO bond strength is 1.60 eV. Computed vibrational frequencies for Co2CO+ and Co2CO- are included for comparison. (C) 2002 American Institute of Physics. C1 Univ Paris 06, LADIR Spectrochim Mol, CNRS, UMR 7075, F-75252 Paris, France. Univ Virginia, Dept Chem, Charlottesville, VA 22901 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Univ Paris 06, LADIR Spectrochim Mol, CNRS, UMR 7075, Case 49,4 Pl Jussieu, F-75252 Paris, France. EM tremblay@ccr.jussieu.fr; ggutsev@mail.arc.nasa.gov NR 45 TC 27 Z9 27 U1 0 U2 4 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 0021-9606 EI 1089-7690 J9 J CHEM PHYS JI J. Chem. Phys. PD NOV 8 PY 2002 VL 117 IS 18 BP 8479 EP 8485 DI 10.1063/1.1512652 PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 610YY UT WOS:000178990700036 ER PT J AU Cottam, J Paerels, F Mendez, M AF Cottam, J Paerels, F Mendez, M TI Gravitationally redshifted absorption lines in the X-ray burst spectra of a neutron star SO NATURE LA English DT Article ID PHOTON IMAGING CAMERA; XMM-NEWTON; MILLISECOND PULSAR; MASS; SPECTROSCOPY; DISCOVERY AB The fundamental properties of neutron stars provide a direct test of the equation of state of cold nuclear matter, a relationship between pressure and density that is determined by the physics of the strong interactions between the particles that constitute the star. The most straightforward method of determining these properties is by measuring the gravitational redshift of spectral lines produced in the neutron star photosphere(1). The equation of state implies a mass-radius relation, while a measurement of the gravitational redshift at the surface of a neutron star provides a direct constraint on the mass-to-radius ratio. Here we report the discovery of significant absorption lines in the spectra of 28 bursts of the low-mass X-ray binary EXO0748-676. We identify the most significant features with the Fe XXVI and XXV n = 2-3 and O VIII n = 1-2 transitions, all with a redshift of z = 0.35, identical within small uncertainties for the respective transitions. For an astrophysically plausible range of masses (M approximate to 1.3-2.0 solar masses; refs 2-5), this value is completely consistent with models of neutron stars composed of normal nuclear matter, while it excludes some models(6,7) in which the neutron stars are made of more exotic matter. C1 NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. Columbia Univ, Columbia Astrophys Lab, New York, NY 10027 USA. Columbia Univ, Dept Astron, New York, NY 10027 USA. SRON, Natl Inst Space Res, NL-3584 CA Utrecht, Netherlands. RP NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. EM jcottam@milkyway.gsfc.nasa.gov RI Mendez, Mariano/C-8011-2012 OI Mendez, Mariano/0000-0003-2187-2708 NR 28 TC 288 Z9 291 U1 0 U2 2 PU NATURE PUBLISHING GROUP PI LONDON PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 EI 1476-4687 J9 NATURE JI Nature PD NOV 7 PY 2002 VL 420 IS 6911 BP 51 EP 54 DI 10.1038/nature01159 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 612HJ UT WOS:000179068100032 PM 12422210 ER PT J AU Hodis, HN Mack, WJ LaBree, LD Mahrer, PR Sevanian, A Liu, CR Liu, CH Hwang, J Selzer, RH Azen, SP AF Hodis, HN Mack, WJ LaBree, LD Mahrer, PR Sevanian, A Liu, CR Liu, CH Hwang, J Selzer, RH Azen, SP TI Alpha-tocopherol supplementation in healthy individuals: Results from the Vitamin E Atherosclerosis Prevention Study (VEAPS) SO CIRCULATION LA English DT Meeting Abstract CT American-Heart-Association Abstracts From Scientific Sessions CY NOV 17-20, 2002 CL CHICAGO, ILLINOIS SP Amer Heart Assoc C1 Univ So Calif, Los Angeles, CA USA. Kaiser Permanente Med Ctr, Los Angeles, CA 90034 USA. Jet Prop Lab, Pasadena, CA USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU LIPPINCOTT WILLIAMS & WILKINS PI PHILADELPHIA PA 530 WALNUT ST, PHILADELPHIA, PA 19106-3621 USA SN 0009-7322 J9 CIRCULATION JI Circulation PD NOV 5 PY 2002 VL 106 IS 19 SU S MA 3640 BP 741 EP 741 PG 1 WC Cardiac & Cardiovascular Systems; Peripheral Vascular Disease SC Cardiovascular System & Cardiology GA 613QJ UT WOS:000179142703676 ER PT J AU Hodis, HN Mack, WJ Lobo, R Mahrer, PR Liu, CR Liu, CH Selzer, RH Azen, SP AF Hodis, HN Mack, WJ Lobo, R Mahrer, PR Liu, CR Liu, CH Selzer, RH Azen, SP TI Estrogen replacement therapy effects on the progression of subclinical atherosclerosis are mediated by lipids but not by carbohydrate metabolic factors: Results from the Estrogen in the Prevention of Atherosclerosis Trial (EPAT) SO CIRCULATION LA English DT Meeting Abstract CT American-Heart-Association Abstracts From Scientific Sessions CY NOV 17-20, 2002 CL CHICAGO, ILLINOIS SP Amer Heart Assoc C1 Univ So Calif, Los Angeles, CA USA. Columbia Univ, New York, NY USA. Kaiser Permanente Med Ctr, Los Angeles, CA 90034 USA. CALTECH, Jet Prop Lab, Pasadena, CA USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU LIPPINCOTT WILLIAMS & WILKINS PI PHILADELPHIA PA 530 WALNUT ST, PHILADELPHIA, PA 19106-3621 USA SN 0009-7322 J9 CIRCULATION JI Circulation PD NOV 5 PY 2002 VL 106 IS 19 SU S MA 3657 BP 744 EP 744 PG 1 WC Cardiac & Cardiovascular Systems; Peripheral Vascular Disease SC Cardiovascular System & Cardiology GA 613QJ UT WOS:000179142703693 ER PT J AU Mitchell, CA Bahr, JL Arepalli, S Tour, JM Krishnamoorti, R AF Mitchell, CA Bahr, JL Arepalli, S Tour, JM Krishnamoorti, R TI Dispersion of functionalized carbon nanotubes in polystyrene SO MACROMOLECULES LA English DT Article ID LAYERED-SILICATE NANOCOMPOSITES; POLYMER MELT INTERCALATION; DIBLOCK CO-POLYMER; MECHANICAL-PROPERTIES; NYLON-6-CLAY HYBRID; EPSILON-CAPROLACTAM; COPOLYMER MICELLES; PHASE-SEPARATION; BINARY-MIXTURES; BEHAVIOR AB Polystyrene nanocomposites with functionalized single-walled carbon nanotubes (SWNTs), prepared by the in-situ generation and reaction of organic diazonium compounds, were characterized using melt-state linear dynamic viscoelastic measurements. These were contrasted to the properties of polystyrene composites prepared with unfunctionalized SWNTs at similar loadings. The functionalized nanocomposites demonstrated a percolated SWNT network structure at concentrations of 1 vol % SWNT, while the unfunctionalized SWNT-based composites at twice the loading of SWNT exhibited viscoelastic behavior comparable to that of the unfilled polymer. This formation of the SWNT network structure for the functionalized SWNT-based composites is because of the improved compatibility between the SWNTs and the polymer matrix and the resulting better dispersion of the SWNT. C1 Univ Houston, Dept Chem Engn, Houston, TX 77204 USA. Rice Univ, Dept Chem, Houston, TX 77005 USA. Rice Univ, Dept Mech Engn & Mat Sci, Houston, TX 77005 USA. Rice Univ, Ctr Nanoscale Sci & Technol, Houston, TX 77005 USA. NASA, Lyndon B Johnson Space Ctr, GB Tech 1, Houston, TX 77058 USA. RP Mitchell, CA (reprint author), Univ Houston, Dept Chem Engn, Houston, TX 77204 USA. RI Krishnamoorti, Ramanan/F-7914-2011; OI Krishnamoorti, Ramanan/0000-0001-5831-502X; Tour, James/0000-0002-8479-9328 NR 62 TC 467 Z9 471 U1 9 U2 111 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0024-9297 J9 MACROMOLECULES JI Macromolecules PD NOV 5 PY 2002 VL 35 IS 23 BP 8825 EP 8830 DI 10.1021/ma020890y PG 6 WC Polymer Science SC Polymer Science GA 610HF UT WOS:000178954100028 ER PT J AU Maley, PD Moore, RG King, DJ AF Maley, PD Moore, RG King, DJ TI Starshine: A student-tracked atmospheric research satellite SO ACTA ASTRONAUTICA LA English DT Article AB An experimental satellite called STARSHINE has been built and launched that enabled students on dive continents to take part in its assembly and then to watch the satellite interacting with the earth's atmosphere. The satellite is a hollow sphere with small aluminum mirrors polished by groups of students in 18 countries. After deployment from the Space Shuttle, flashes of sunlight allow the satellite to be spotted at night to the naked eye. It is hoped that students can also make orbit determinations, forecast future visibility and perform atmospheric density computations during the projected 8-month life span of STARSHINE. (C) 2002 Elsevier Science Ltd. All rights reserved. C1 USN, Res Lab, Washington, DC 20375 USA. Project STARSHINE, Monument, CO 80132 USA. United Space Alliance, Houston, TX 77058 USA. RP Maley, PD (reprint author), Lyndon B Johnson Space Ctr, Mail Code D05-P,Maley 2101 NASA Rd 1, Houston, TX 77058 USA. NR 0 TC 1 Z9 1 U1 2 U2 3 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0094-5765 J9 ACTA ASTRONAUT JI Acta Astronaut. PD NOV PY 2002 VL 51 IS 10 BP 715 EP 721 AR PII S0094-5765(02)00021-8 DI 10.1016/S0094-5765(02)00021-8 PG 7 WC Engineering, Aerospace SC Engineering GA 609FA UT WOS:000178891900007 ER PT J AU Blamont, J Jones, JA AF Blamont, J Jones, JA TI A new method for landing on Mars SO ACTA ASTRONAUTICA LA English DT Article AB Up to now, the only means to land payloads on Mars have involved a heavy, complicated, expensive retro-rocket landing system. Another method to land payloads is to use a novel solar heated hot-air balloon, or Solar Montgolfiere, which looks promising to replace the retro-rocket landing system, while increasing usable landed payload. The Solar Montgolfiere is a simple device that deploys like a parachute, fills with ambient atmosphere, and then quickly heats up by solar heating. to achieve significant buoyancy within 1-2 min. The combined effect of the balloon buoyancy and the parachuting effect of the balloon results in landing speeds of < 5 m/s for the payload, as opposed to Pathfinder retro-rocket landing speeds of about 20 m/s. Using this balloon landing system enables a number of payloads with entry masses as large as 15 kg to be carried inexpensively to Mars on the Ariane 5 Piggyback launches. (C) 2002 Elsevier Science Ltd. All rights reserved. C1 Ctr Natl Etud Spatiales, F-75039 Paris 01, France. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Blamont, J (reprint author), Ctr Natl Etud Spatiales, 2,Pl Maurice Quentin, F-75039 Paris 01, France. NR 4 TC 3 Z9 5 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0094-5765 J9 ACTA ASTRONAUT JI Acta Astronaut. PD NOV PY 2002 VL 51 IS 10 BP 723 EP 726 AR PII S0094-5765(02)00019-X DI 10.1016/S0094-5765(02)00019-X PG 4 WC Engineering, Aerospace SC Engineering GA 609FA UT WOS:000178891900008 ER PT J AU Mankins, JC AF Mankins, JC TI Highly reusable space transportation: Advanced concepts and the opening of the space frontier SO ACTA ASTRONAUTICA LA English DT Article AB Revolutionary changes in how cargo and people are transported into space are needed to enable the affordable development and exploration of space in the 21st century. Diverse efforts to achieve major, but incremental Earth-to-orbit (ETO) improvements in the relatively near term have been undertaken in recent years in the US, including the Department of Defense evolved,expendable launch vehicle system development project. The NASA-industry reusable launch vehicle (RLV) program is addressing this challenge for the mid-term. The RLV program will validate the technology to enable industry to develop all-rocket reusable launch systems that can deliver payloads from the current Civil Needs Data Base in the 20,000-40,000 pounds class and smaller to low Earth orbit (LEO) at costs. of approximately $1000-$2000 per pound. This represents a factor of 5 (or more) reduction below existing launch services. This "next generation" improvement in launch capability is a vital element of the US National Space Transportation policy for current and planned government and commercial payloads. The longer-term challenge is also being addressed. During 1995-1997, NASA conducted the highly reusable space transportation (HRST) study project to address the longer-term challenge: how to achieve an additional factor of 10 reduction in launch costs-to approximately $100-$200 per payload pound to LEO-thus enabling a revolutionary expansion of space activity and enterprise. The HRST study has identified a "grand strategy" for achieving these cost goals, based on pursuing a revolutionary advance in main propulsion architectures and technology for ETO systems to enable a dramatic improvements in subsystem operability. The HRST study has examined diverse approaches, including combination propulsion systems, combined cycle propulsion, launch assist systems, and revolutionary rocket propulsion. An integrated assessment has been conducted, including both the concepts defined as part of the study as well as past concepts. This assessment suggests that the cost goals of HRST are achievable within the next 10-20 years if appropriate technology investments are pursued. This paper provides a summary report on the results and findings of the HRST study project. Published by Elsevier Science Ltd. C1 NASA, Adv Projects Off, Head Quarters Off, Off Space Flight, Washington, DC 20546 USA. RP Mankins, JC (reprint author), NASA, Adv Projects Off, Head Quarters Off, Off Space Flight, 300 E St,SW, Washington, DC 20546 USA. NR 23 TC 3 Z9 3 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0094-5765 J9 ACTA ASTRONAUT JI Acta Astronaut. PD NOV PY 2002 VL 51 IS 10 BP 727 EP 742 AR PII S0094-5765(02)00020-6 DI 10.1016/S0094-5765(02)00020-6 PG 16 WC Engineering, Aerospace SC Engineering GA 609FA UT WOS:000178891900009 ER PT J AU Schairer, ET AF Schairer, ET TI Optimum thickness of pressure-sensitive paint for unsteady measurements SO AIAA JOURNAL LA English DT Article ID POLYMER AB When pressure-sensitive paint (PSP) is used to measure unsteady pressures, the thickness of the paint layer critically affects both the PSP signal-to-noise ratio (SNR) and frequency response. As the thickness of a paint layer increases, the brightness of the signal, and thus the SNR, increases, whereas the frequency response decreases, resulting in attenuation of the unsteady component of the signal. In addition, if pressure fluctuations and frequencies are large and the paint layer is thick, the unsteady PSP signal may be distorted and the steady component may be offset from its true mean value. These observations suggest that, for each application, there is an optimum paint thickness where the "unsteady SNR" (the ratio of unsteady signal amplitude to steady noise) is a maximum and where the offset and distortion are small. This hypothesis is explored by numerically evaluating published analytic solutions to a simplified model of the unsteady PSP problem. It was found that over a wide range of parameters the unsteady SNR is a maximum when the paint thickness corresponds to a 1.25 dB attenuation of the unsteady signal. At this optimum, the nondimensional time constant (h(2) omega/D) is approximately 1.5. C1 NASA, Ames Res Ctr, Syst Anal Branch, Moffett Field, CA 94035 USA. RP Schairer, ET (reprint author), NASA, Ames Res Ctr, Syst Anal Branch, Moffett Field, CA 94035 USA. NR 19 TC 14 Z9 15 U1 0 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0001-1452 J9 AIAA J JI AIAA J. PD NOV PY 2002 VL 40 IS 11 BP 2312 EP 2318 DI 10.2514/2.1568 PG 7 WC Engineering, Aerospace SC Engineering GA 608XA UT WOS:000178872000016 ER PT J AU Clemett, SJ Thomas-Keprta, KL Shimmin, J Morphew, M McIntosh, JR Bazylinski, DA Kirschvink, JL Wentworth, SJ McKay, DS Vali, H Gibson, EK Romanek, CS AF Clemett, SJ Thomas-Keprta, KL Shimmin, J Morphew, M McIntosh, JR Bazylinski, DA Kirschvink, JL Wentworth, SJ McKay, DS Vali, H Gibson, EK Romanek, CS TI Crystal morphology of MV-1 magnetite SO AMERICAN MINERALOGIST LA English DT Article ID ALH84001 AB Intracellular magnetite (Fe3O4) crystals produced by magnetotactic bacteria strain MV-1 are in the single-domain size range, and are chemically pure. We have previously suggested that they exhibit an unusual crystal habit described as truncated hexa-octahedral. Such a crystal morphology has not been demonstrated for any inorganic population of magnetite, nor would it be expected, given considerations of symmetry and free energy. By inference, this morphology is a physical signature of a biological origin. Here we report data from transmission electron microscope (TEM) tomography of such crystals isolated from magnetotactic bacteria, which confirm the unusual geometry, originally proposed from classical TEM tilt imaging. C1 NASA, Lyndon B Johnson Space Ctr, Astrobil Inst, Lockheed Martin Space Operat, Houston, TX 77058 USA. Univ Georgia, Savannah River Ecol Lab, Aiken, SC 29802 USA. McGill Univ, Dept Earth & Planetary Sci, Montreal, PQ H3A 2A7, Canada. CALTECH, Div Geol & Planetary Sci, Pasadena, CA 91125 USA. Iowa State Univ Sci & Technol, Dept Microbiol, Ames, IA 50011 USA. Univ Colorado, Dept Mol Cellular & Dev Biol, Boulder, CO 80309 USA. RP Clemett, SJ (reprint author), NASA, Lyndon B Johnson Space Ctr, Astrobil Inst, Lockheed Martin Space Operat, 2400 NASA Rd 1,Mail Code C23, Houston, TX 77058 USA. RI Vali, Hojatollah/F-3511-2012 OI Vali, Hojatollah/0000-0003-3464-9943 NR 14 TC 24 Z9 25 U1 0 U2 8 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 NOV-DEC PY 2002 VL 87 IS 11-12 BP 1727 EP 1730 PG 4 WC Geochemistry & Geophysics; Mineralogy SC Geochemistry & Geophysics; Mineralogy GA 618JZ UT WOS:000179416100024 ER PT J AU Woo, R Habbal, SR AF Woo, R Habbal, SR TI The origin of the solar wind - A novel way of looking at the solar corona reveals a hidden "imprint" of the Sun SO AMERICAN SCIENTIST LA English DT Article ID SLOW C1 CALTECH, NASAs Jet Prop Lab, Pasadena, CA USA. Univ Wales, Aberystwyth, Dyfed, Wales. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Woo, R (reprint author), JPL, 4800 oak Grove Dr,MS 238-725, Pasadena, CA 91109 USA. EM richard.woo@jpl.nasa.gov NR 17 TC 6 Z9 7 U1 0 U2 1 PU SIGMA XI-SCI RES SOC PI RES TRIANGLE PK PA PO BOX 13975, RES TRIANGLE PK, NC 27709 USA SN 0003-0996 J9 AM SCI JI Am. Scientist PD NOV-DEC PY 2002 VL 90 IS 6 BP 532 EP 539 PG 8 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 603HR UT WOS:000178553700016 ER PT J AU Sheverev, VA Khromov, NA Kojiro, DR AF Sheverev, VA Khromov, NA Kojiro, DR TI Penning ionization electron spectroscopy in glow discharge: Another dimension for gas chromatography detectors SO ANALYTICAL CHEMISTRY LA English DT Article ID MOLECULAR-ORBITALS; PLASMA; ATOMS AB Admixtures to helium of 100 and 5 ppm of nitrogen, and 100 and 10 ppm of carbon monoxide were identified and measured in the helium discharge afterglow using an electrical probe placed into the plasma. For nitrogen and carbon monoxide gases, the measured electron energy spectra display distinct characteristic peaks (fingerprints). Location of the peaks on the energy scale is determined by the ionization energies of the analyte molecules. Nitrogen and carbon monoxide fingerprints were also observed in a binary mixture of these gases in helium, and the relative concentration of analytes has been predicted. The technically simple and durable method is considered a good candidate for a number of analytical applications, and in particular, in GC and for analytical flight instrumentation. C1 Polytech Univ, Brooklyn, NY 11201 USA. Glimmerglass Sci & Technol Corp, Utica, NY 13501 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Sheverev, VA (reprint author), Polytech Univ, 6 Metrotech Ctr, Brooklyn, NY 11201 USA. NR 17 TC 9 Z9 9 U1 0 U2 6 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0003-2700 J9 ANAL CHEM JI Anal. Chem. PD NOV 1 PY 2002 VL 74 IS 21 BP 5556 EP 5563 DI 10.1021/ac0203342 PG 8 WC Chemistry, Analytical SC Chemistry GA 611QB UT WOS:000179028300022 PM 12433088 ER PT J AU Blumberg, BS AF Blumberg, BS TI Astrobiology: An introduction SO ANATOMICAL RECORD LA English DT Editorial Material C1 NASA, Ames Res Ctr, Astrobiol Inst, Moffett Field, CA 94035 USA. RP Blumberg, BS (reprint author), NASA, Ames Res Ctr, Astrobiol Inst, MS 240-1, Moffett Field, CA 94035 USA. NR 0 TC 0 Z9 0 U1 0 U2 3 PU WILEY-LISS PI NEW YORK PA DIV JOHN WILEY & SONS INC, 605 THIRD AVE, NEW YORK, NY 10158-0012 USA SN 0003-276X J9 ANAT REC JI Anat. Rec. PD NOV 1 PY 2002 VL 268 IS 3 BP 169 EP 170 DI 10.1002/ar.10150 PG 2 WC Anatomy & Morphology SC Anatomy & Morphology GA 608WN UT WOS:000178870800001 PM 12382314 ER PT J AU Laakso, H Pfaff, R Janhunen, P AF Laakso, H Pfaff, R Janhunen, P TI Polar observations of electron density distribution in the Earth's magnetosphere. 1. Statistical results SO ANNALES GEOPHYSICAE LA English DT Article DE magnetospheric physics; magnetospheric configuration and dynamics plasmasphere; polar cap phenomena ID SOLAR-WIND; POTENTIAL MEASUREMENTS; FIELD MEASUREMENTS; PLASMA; INSTRUMENT; DYNAMICS; REGIONS; CUSP; CAP AB Forty-five months of continuous spacecraft potential measurements from the Polar satellite are used to study the average electron density in the magnetosphere and its dependence on geomagnetic activity and season. These measurements offer a straightforward, passive method for monitoring the total electron density in the magnetosphere, with high time resolution and a density range that covers many orders of magnitude. Within its polar orbit with geocentric perigee and apogee of 1.8 and 9.0 R-E, respectively, Polar encounters a number of key plasma regions of the magnetosphere, such as the polar cap, cusp, plasmapause, and auroral zone that are clearly identified in the statistical averages presented here. The polar cap density behaves quite systematically with season. At low distance (similar to2 R-E), the density is an order of magnitude higher in summer than in winter; at high distance (>4 R-E), the variation is somewhat smaller. Along a magnetic field line the density declines between these two altitudes by a factor of 10-20 in winter and by a factor of 200-1000 in summer. A likely explanation for the large gradient in the summer is a high density of heavy ions that are gravitationally bound in the low-altitude polar cap. The geomagnetic effects are also significant in the polar cap, with the average density being an order of magnitude larger for high K-p; for an individual case, the polar cap density may increase even more dramatically. The plasma density in the cusp is controlled primarily by the solar wind variables, but nevertheless, they can be characterized to some extent in terms of the Kp index. We also investigate the local time variation of the average density at the geosynchronous distance that appears to be in accordance with previous geostationary observations. The average density decreases with increasing Kp at all MLT sectors, except at 14-17 MLT, where the average density remains constant. At all MLT sectors the range of the density varies by more than 3 orders of magnitude, since the geostationary orbit may cut through different plasma regions, such as the plasma sheet, trough, and plasmasphere. C1 ESA, Dept Space Sci, Noordwijk, Netherlands. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Finnish Meteorol Inst, FIN-00101 Helsinki, Finland. RP Laakso, H (reprint author), ESA, Dept Space Sci, Noordwijk, Netherlands. RI Pfaff, Robert/F-5703-2012 OI Pfaff, Robert/0000-0002-4881-9715 NR 28 TC 17 Z9 17 U1 0 U2 0 PU EUROPEAN GEOPHYSICAL SOC PI KATLENBURG-LINDAU PA MAX-PLANCK-STR 13, 37191 KATLENBURG-LINDAU, GERMANY SN 0992-7689 J9 ANN GEOPHYS-GERMANY JI Ann. Geophys. PD NOV PY 2002 VL 20 IS 11 BP 1711 EP 1724 PG 14 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA 633UN UT WOS:000180301300002 ER PT J AU Laakso, H Pfaff, R Janhunen, P AF Laakso, H Pfaff, R Janhunen, P TI Polar observations of electron density distribution in the Earth's magnetosphere. 2. Density profiles SO ANNALES GEOPHYSICAE LA English DT Article DE magnetospheric physics; auroral phenomena; plasmasphere; polar cap phenomena ID GEOSYNCHRONOUS ORBIT; PLASMA; SATELLITE; EVOLUTION; MODEL; CUSP AB Using spacecraft potential measurements of the Polar electric field experiment, we investigate electron density variations of key plasma regions within the magnetosphere, including the polar cap, cusp, trough, plasmapause, and auroral zone. The statistical results were presented in the first part of this study, and the present paper reports detailed structures revealed by individual satellite passes. The high-altitude (>3 R-E) polar cap is generally one of the most tenuous regions in the magnetosphere, but surprisingly, the polar cap boundary does not appear as a steep density decline. At low altitudes (1 R-E) in summer, the polar densities are very high, several 100 cm(-3), and interestingly, the density peaks at the central polar cap. On the noonside of the polar cap, the cusp appears as a dense, 1-3degrees wide region. A typical cusp density above 4 R-E distance is between several 10 cm(-3) and a few 100 cm(-3). On some occasions the cusp is crossed multiple times in a single pass, simultaneously with the occurrence of IMF excursions, as the cusp can instantly shift its position under varying solar wind conditions, similar to the magnetopause. On the nightside, the auroral zone is not always detected as a simple density cavity. Cavities are observed but their locations, strengths, and sizes vary. Also, the electric field perturbations do not necessarily overlap with the cavities: there are cavities with no field disturbances, as well as electric field disturbances observed with no clear cavitation. In the inner magnetosphere, the density distributions clearly show that the plasmapause and trough densities are well correlated with geomagnetic activity. Data from individual orbits near noon and midnight demonstrate that at the beginning of geomagnetic disturbances, the retreat speed of the plasmapause can be one L-shell per hour, while during quiet intervals the plasmapause can expand anti-earthward at the same speed. For the trough region, it is found that the density tends to be an order of magnitude higher on the day-side (similar to1 cm(-3)) than on the nightside (similar to0.1-1 cm(-3)), particularly during low K-p. C1 ESA, Dept Space Sci, Noordwijk, Netherlands. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Finnish Meteorol Inst, FIN-00101 Helsinki, Finland. RP Laakso, H (reprint author), ESA, Dept Space Sci, Noordwijk, Netherlands. RI Pfaff, Robert/F-5703-2012 OI Pfaff, Robert/0000-0002-4881-9715 NR 23 TC 13 Z9 13 U1 0 U2 2 PU EUROPEAN GEOPHYSICAL SOC PI KATLENBURG-LINDAU PA MAX-PLANCK-STR 13, 37191 KATLENBURG-LINDAU, GERMANY SN 0992-7689 J9 ANN GEOPHYS-GERMANY JI Ann. Geophys. PD NOV PY 2002 VL 20 IS 11 BP 1725 EP 1735 PG 11 WC Astronomy & Astrophysics; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Astronomy & Astrophysics; Geology; Meteorology & Atmospheric Sciences GA 633UN UT WOS:000180301300003 ER PT J AU Wilson, JW Ott, CM Ramamurthy, R Porwollik, S McClelland, M Pierson, DL Nickerson, CA AF Wilson, JW Ott, CM Ramamurthy, R Porwollik, S McClelland, M Pierson, DL Nickerson, CA TI Low-shear modeled microgravity alters the Salmonella enterica serovar typhimurium stress response in an RpoS-independent manner SO APPLIED AND ENVIRONMENTAL MICROBIOLOGY LA English DT Article ID SIGMA-FACTOR KATF; ESCHERICHIA-COLI; GENE-EXPRESSION; VIRULENCE; ACID; CELLS; SPACE; PHASE; REGULATOR; CULTURE AB We have previously demonstrated that low-shear modeled microgravity (low-shear MMG) serves to enhance the virulence of a bacterial pathogen, Salmonella enterica serovar Typhimurium. The Salmonella response to low-shear MMG involves a signaling pathway that we have termed the low-shear MMG stimulon, though the identities of the low-shear MMG stimulon genes and regulatory factors are not known. RpoS is the primary sigma factor required for the expression of genes that are induced upon exposure to different environmental-stress signals and is essential for virulence in mice. Since low-shear MMG induces a Salmonella acid stress response and enhances Salmonella virulence, we reasoned that RpoS would be a likely regulator of the Salmonella low-shear MMG response. Our results demonstrate that low-shear MMG provides cross-re si stance to several environmental stresses in both wild-type and isogenic rpoS mutant strains. Growth under low-shear MMG decreased the generation time of both strains in minimal medium and increased the ability of both strains to survive in J774 macrophages. Using DNA microarray analysis, we found no evidence of induction of the RpoS regulon by low-shear MMG but did find that other genes were altered in expression under these conditions in both the wild-type and rpoS mutant strains. Our results indicate that, under the conditions of these studies, RpoS is not required for transmission of the signal that induces the low-shear MMG stimulon. Moreover, our studies also indicate that low-shear MMG can be added to a short list of growth conditions that can serve to preadapt an rpoS mutant for resistance to multiple environmental stresses. C1 Tulane Univ, Sch Med, Dept Microbiol & Immunol, Program Mol Pathogenesis & Immun, New Orleans, LA 70112 USA. NASA, Lyndon B Johnson Space Ctr, EASI, Wyle Labs, Houston, TX 77058 USA. NASA, Lyndon B Johnson Space Ctr, Life Sci Res Labs, Houston, TX 77058 USA. Sidney Kimmel Canc Ctr, San Diego, CA 92121 USA. RP Nickerson, CA (reprint author), Tulane Univ, Sch Med, Dept Microbiol & Immunol, Program Mol Pathogenesis & Immun, New Orleans, LA 70112 USA. RI McClelland, Michael/A-8583-2011; OI McClelland, Michael/0000-0003-1788-9347 NR 43 TC 67 Z9 80 U1 1 U2 11 PU AMER SOC MICROBIOLOGY PI WASHINGTON PA 1752 N ST NW, WASHINGTON, DC 20036-2904 USA SN 0099-2240 J9 APPL ENVIRON MICROB JI Appl. Environ. Microbiol. PD NOV PY 2002 VL 68 IS 11 BP 5408 EP 5416 DI 10.1128/AEM.68.11.5408-5416.2002 PG 9 WC Biotechnology & Applied Microbiology; Microbiology SC Biotechnology & Applied Microbiology; Microbiology GA 611PU UT WOS:000179027600026 PM 12406731 ER PT J AU Vora, J Nair, S Gramopadhye, AK Duchowski, AT Melloy, BJ Kanki, B AF Vora, J Nair, S Gramopadhye, AK Duchowski, AT Melloy, BJ Kanki, B TI Using virtual reality technology for aircraft visual inspection training: presence and comparison studies SO APPLIED ERGONOMICS LA English DT Article DE virtual reality; eye tracking; visual inspection; training; presence ID STRATEGIES; ENVIRONMENTS; SEARCH AB The aircraft maintenance industry is a complex system consisting of several interrelated human and machine components. Recognizing this, the Federal Aviation Administration (FAA) has pursued human factors related research. In the maintenance arena the research has focused on the aircraft inspection process and the aircraft inspector. Training has been identified as the primary intervention strategy to improve the quality and reliability of aircraft inspection. If training is to be successful, it is critical that we provide aircraft inspectors with appropriate training tools and environment. In response to this need, the paper outlines the development of a virtual reality (VR) system for aircraft inspection training. VR has generated much excitement but little formal proof that it is useful. However, since VR interfaces are difficult and expensive to build, the computer graphics community needs to be able to predict which applications will benefit from VR. To address this important issue, this research measured the degree of immersion and presence felt by subjects in a virtual environment simulator. Specifically, it conducted two controlled studies using the VR system developed for visual inspection task of an aft-cargo bay at the VR Lab of Clemson University. Beyond assembling the visual inspection virtual environment, a significant goal of this project was to explore subjective presence as it affects task performance. The results of this study indicated that the system scored high on the issues related to the degree of presence felt by the subjects. As a next logical step, this study, then, compared VR to an existing PC-based aircraft inspection simulator. The results showed that the VR system was better and preferred over the PC-based training tool. (C) 2002 Elsevier Science Ltd. All rights reserved. C1 Clemson Univ, Coll Engn & Sci, Dept Ind Engn, Clemson, SC 29634 USA. Clemson Univ, Dept Comp Sci Engn, Clemson, SC 29634 USA. NASA, Ames Res Ctr, Ames, IA USA. RP Gramopadhye, AK (reprint author), Clemson Univ, Coll Engn & Sci, Dept Ind Engn, Clemson, SC 29634 USA. NR 40 TC 41 Z9 44 U1 3 U2 13 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0003-6870 J9 APPL ERGON JI Appl. Ergon. PD NOV PY 2002 VL 33 IS 6 BP 559 EP 570 AR PII S0003-6870(02)00039-X DI 10.1016/S0003-6870(02)00039-X PG 12 WC Engineering, Industrial; Ergonomics; Psychology, Applied SC Engineering; Psychology GA 623WE UT WOS:000179725200006 PM 12507340 ER PT J AU Griffin, MJ Bock, JJ Gear, WK AF Griffin, MJ Bock, JJ Gear, WK TI Relative performance of filled and feedhorn-coupled focal-plane architectures SO APPLIED OPTICS LA English DT Article ID BOLOMETER ARRAY; CAMERA; INSTRUMENT; TELESCOPE; HERSCHEL AB Modern far-infrared and submillimeter instruments require large-format arrays. We consider the relative performance of filled-array (bare pixel) and feedhorn-coupled architectures for bolometer focal planes. Based on typical array parameters, we quantify the relative observing speeds and comment on the merits of the different architectures. Filled arrays can provide higher mapping speed (by a factor of as much as 3.5) and simpler observing modes at the expense of reduced sensitivity for pointed observations, increased detector numbers, and greater vulnerability to stray light and electromagnetic interference. Taking advantage of the filled-array architecture requires strongly background-limited detectors. At millimeter wavelengths, filled arrays must-be surrounded by a sufficiently cold enclosure to minimize the background power from the instrument itself. (C) 2002 Optical Society of America. C1 Cardiff Univ, Dept Phys & Astron, Cardiff CF24 3YB, S Glam, Wales. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Griffin, MJ (reprint author), Cardiff Univ, Dept Phys & Astron, Queens Bldg,POB 913,5 Parade, Cardiff CF24 3YB, S Glam, Wales. EM matt.griffin@astro.cf.ac.uk NR 20 TC 73 Z9 73 U1 0 U2 3 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1559-128X EI 2155-3165 J9 APPL OPTICS JI Appl. Optics PD NOV 1 PY 2002 VL 41 IS 31 BP 6543 EP 6554 DI 10.1364/AO.41.006543 PG 12 WC Optics SC Optics GA 608LJ UT WOS:000178847600003 PM 12412645 ER PT J AU Banger, KK Hollingsworth, JA Harris, JD Cowen, J Buhro, WE Hepp, AF AF Banger, KK Hollingsworth, JA Harris, JD Cowen, J Buhro, WE Hepp, AF TI Ternary single-source precursors for polycrystalline thin-film solar cells SO APPLIED ORGANOMETALLIC CHEMISTRY LA English DT Article ID CUINSE2; MICROSTRUCTURE; SEMICONDUCTORS; DEPOSITION; EFFICIENCY; PYROLYSIS; ALLOYS; MOCVD AB The development of thin-film solar cells on flexible, lightweight, spice-qualified substrates provides an attractive cost solution for fabricating solar arrays with high specific power (W kg(-1)). The use of a polycrystalline chalcopyrite absorber layer for thin-film solar cells is considered as the next generation in photovoltaic devices. At NASA GRC we have focused on the development of new single-source precursors (SSPs) and their utility to deposit the chalcopyrite semiconducting layer (CIS) onto flexible substrates for solar-cell fabrication. The syntheses and thermal modulation of SSPs via molecular engineering are described. Thin-film fabrication studies demonstrate that the SSPs can be used in a spray chemical vapor deposition process for depositing CIS at reduced temperatures, and result in electrical properties that are suitable for photovoltaic devices. Copyright (C) 2002, John Wiley Sons, Ltd. C1 NASA, Glenn Res Ctr, Photovolta & Space Environm Branch, Cleveland, OH 44135 USA. Ohio Aerosp Inst, Cleveland, OH 44142 USA. Washington Univ, Dept Chem, St Louis, MO 63130 USA. Cleveland State Univ, Dept Chem, Cleveland, OH 44115 USA. RP Hepp, AF (reprint author), NASA, Glenn Res Ctr, Photovolta & Space Environm Branch, 21000 Brookpk Rd,Mail Stop 302-1, Cleveland, OH 44135 USA. EM aloysius.f.hepp@grc.nasa.gov RI Buhro, William/A-7682-2009 NR 46 TC 29 Z9 29 U1 0 U2 8 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 0268-2605 J9 APPL ORGANOMET CHEM JI Appl. Organomet. Chem. PD NOV PY 2002 VL 16 IS 11 BP 617 EP 627 DI 10.1002/aoc.362 PG 13 WC Chemistry, Applied; Chemistry, Inorganic & Nuclear SC Chemistry GA 612XZ UT WOS:000179101900001 ER PT J AU Miller, NA Owen, FN AF Miller, NA Owen, FN TI Evolution of star-forming and active galaxies in nearby clusters SO ASTRONOMICAL JOURNAL LA English DT Article DE galaxies : clusters : general; galaxies : evolution; radio continuum ID CAMPANAS REDSHIFT SURVEY; RADIO-SOURCE POPULATIONS; EMISSION-LINE SPECTRA; 4000 ANGSTROM BREAK; DISTANT CLUSTERS; ABELL CLUSTERS; RICH CLUSTERS; STARBURST GALAXIES; COMPACT-GROUPS; S0 GALAXIES AB We have used optical spectroscopy to investigate the active galaxy populations in a sample of 20 nearby Abell clusters. The targets were identified on the basis of 1.4 GHz radio emission, which identifies them as either active galactic nuclei (AGNs) or galaxies forming stars at rates comparable to or greater than that of the Milky Way. The spectra were used to characterize the galaxies via their emission and absorption features. The spectroscopy results reveal a significant population of star-forming galaxies with large amounts of nuclear dust extinction. This extinction eliminates bluer emission lines such as [O II] from the spectra of these galaxies, meaning their star formation could easily be overlooked in studies that focus on such features. Around 20% of the cluster star-forming galaxies have spectra of this type. The radial distributions of active galaxies in clusters show a strong segregation between star-forming galaxies and AGNs, with star-forming galaxies broadly distributed and AGNs preferentially in the cluster cores. The radial distribution of the dusty star-forming galaxies is more centrally concentrated than the star-forming galaxies in general, which argues that they are a consequence of some cluster environmental effect. Furthermore, we note that such galaxies may be identified using their 4000 Angstrom break strengths. We find that discrepancies in reported radio luminosity functions for AGNs are likely the result of classification differences. There exists a large population of cluster galaxies whose radio fluxes, far-infrared fluxes, and optical magnitudes suggest their radio emission may be powered by stars yet whose spectra lack emission lines. Understanding the nature of these galaxies is critical to assessing the importance of AGNs in the radio luminosity function at low luminosities. We also find that regardless of this population, the crossover point where the radio luminosity function is composed equally of star-forming galaxies and AGNs occurs at lower luminosities in clusters than in the field. This is likely a simple consequence of the reduction in star formation in cluster galaxies and the morphological mix in clusters compared with the field. C1 NASA, UV Opt Astron Branch, Astron & Solar Phys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Natl Radio Astron Observ, Socorro, NM 87801 USA. RP Miller, NA (reprint author), NASA, UV Opt Astron Branch, Astron & Solar Phys Lab, Goddard Space Flight Ctr, Code 681, Greenbelt, MD 20771 USA. NR 72 TC 44 Z9 45 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-6256 J9 ASTRON J JI Astron. J. PD NOV PY 2002 VL 124 IS 5 BP 2453 EP 2470 DI 10.1086/343837 PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 607AL UT WOS:000178768200007 ER PT J AU Beck, SC Turner, JL Langland-Shula, LE Meier, DS Crosthwaite, LP Gorjian, V AF Beck, SC Turner, JL Langland-Shula, LE Meier, DS Crosthwaite, LP Gorjian, V TI Radio-infrared supernebulae in II Zw 40 SO ASTRONOMICAL JOURNAL LA English DT Article DE galaxies : dwarf; galaxies : individual (II Zw 40); galaxies : starburst; galaxies : star clusters; radio continuum ID COMPACT DWARF GALAXIES; STAR-FORMATION; WAVELENGTH SPECTROMETER; CONTINUUM OBSERVATIONS; STARBURST GALAXIES; SPECTROSCOPY; NGC-5253; EMISSION; II-ZW-40; REGIONS AB We report subarcsecond-resolution Very Large Array and Keck mid-infrared imaging of the dwarf starburst galaxy II Zw 40. II Zw 40 contains a bright compact thermal radio and infrared source with all the characteristics of a collection of dense H II regions ionized by at least 14,000 O stars. The supernebula is revealed to consist of multiple sources within an envelope of weaker emission. The radio emission is dominated by free-free emission at 2 cm, and the spectrum of this emission appears to be rising. This suggests that the free-free emission is optically thick at 2 cm and that the individual H II regions are similar to1 pc in size. This complex of "supernebulae" dominates the total infrared luminosity of II Zw 40, although the radio source is less than similar to150 pc in diameter. Multiple super star clusters appear to be forming here, the much larger analogs of large Galactic H II region complexes. C1 Tel Aviv Univ, Dept Phys & Astron, IL-69978 Ramat Aviv, Israel. Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA 90095 USA. Univ Calif Santa Cruz, Dept Astron & Astrophys, Santa Cruz, CA 95064 USA. Astute Networks, San Diego, CA 92127 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Beck, SC (reprint author), Tel Aviv Univ, Dept Phys & Astron, IL-69978 Ramat Aviv, Israel. NR 45 TC 45 Z9 45 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-6256 J9 ASTRON J JI Astron. J. PD NOV PY 2002 VL 124 IS 5 BP 2516 EP 2523 DI 10.1086/343061 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 607AL UT WOS:000178768200011 ER PT J AU Hutchings, JB Crenshaw, DM Kraemer, SB Gabel, JR Kaiser, ME Weistrop, D Gull, TR AF Hutchings, JB Crenshaw, DM Kraemer, SB Gabel, JR Kaiser, ME Weistrop, D Gull, TR TI Balmer and He I absorption in the nuclear spectrum of NGC 4151 SO ASTRONOMICAL JOURNAL LA English DT Article DE galaxies : individual (NGC 4151); galaxies : Seyfert ID NARROW-LINE REGION; NGC-4151; EMISSION AB Spectra taken with the Space Telescope Imaging Spectrograph allow accurate location and extraction of the nuclear spectrum of NGC 4151, with minimal contamination by extended line emission and circumnuclear starlight. Spectra since 1997 show that the P Cygni Balmer and He I absorption seen previously in low nuclear states is present in higher states, with outflow velocity that changes with the nuclear flux. The phenomenon is discussed in terms of some of the absorbers seen in the UV resonance lines, and in terms of outflows from the central source and surrounding torus. C1 Natl Res Council Canada, Herzberg Inst Astrophys, Victoria, BC V9E 2E7, Canada. Georgia State Univ, Dept Phys & Astron, Atlanta, GA 30303 USA. Catholic Univ Amer, Inst Astrophys & Computat Sci, Washington, DC 20064 USA. NASA, Astron & Solar Phys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. Univ Nevada, Dept Phys, Las Vegas, NV 89154 USA. RP Hutchings, JB (reprint author), Natl Res Council Canada, Herzberg Inst Astrophys, 5071 W Saanich Rd, Victoria, BC V9E 2E7, Canada. RI Gull, Theodore/D-2753-2012 OI Gull, Theodore/0000-0002-6851-5380 NR 17 TC 13 Z9 15 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-6256 J9 ASTRON J JI Astron. J. PD NOV PY 2002 VL 124 IS 5 BP 2543 EP 2547 DI 10.1086/344080 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 607AL UT WOS:000178768200013 ER PT J AU Chagnon, G Mennesson, B Perrin, G du Foresto, VC Salome, P Borde, P AF Chagnon, G Mennesson, B Perrin, G du Foresto, VC Salome, P Borde, P TI L '-band interferometric observations of evolved stars SO ASTRONOMICAL JOURNAL LA English DT Article DE stars : AGB and post-AGB; stars : late-type; techniques : interferometric ID MODE GUIDED OPTICS; STELLAR INTERFEROMETER; IOTA INTERFEROMETER; DIFFRACTION LIMIT; R-LEONIS; SURFACE; GIANTS; INSTRUMENT; TELESCOPE; SPACE AB Ten bright Miras, six semiregular variable giants, and two semiregular variable supergiants have been observed with the Infrared-Optical Telescope Array interferometer in the L' band (from 3.4 to 4.1 mum). Observations were carried out in 2000 March and November with the FLUOR/TISIS instrument, using optimized single-mode waveguides for optical recombination and a dedicated chopping system for accurate subtraction of slow thermal background drifts. Four of the sources (the Mira stars R Leo and R Cnc, alpha Ori, and RS Cnc) were observed in both runs. We report on visibility measurements and derive L' broadband uniform disk (UD) diameter best fits for all 18 stars in our sample. We also detect strong departures from UD models in some peculiar cases. C1 Observ Paris, Lab Etud Spatiales & Instrumentat Astrophys, F-92195 Meudon, France. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Chagnon, G (reprint author), Observ Paris, Lab Etud Spatiales & Instrumentat Astrophys, 5 Pl Jules Janssen, F-92195 Meudon, France. NR 24 TC 23 Z9 23 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-6256 J9 ASTRON J JI Astron. J. PD NOV PY 2002 VL 124 IS 5 BP 2821 EP 2832 DI 10.1086/343057 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 607AL UT WOS:000178768200033 ER PT J AU Haisch, KE Barsony, M Greene, TP Ressler, ME AF Haisch, KE Barsony, M Greene, TP Ressler, ME TI An infrared multiplicity survey of Class I/flat-spectrum systems in the rho Ophiuchi and Serpens molecular clouds SO ASTRONOMICAL JOURNAL LA English DT Article DE binaries : close; stars : formation; stars : pre-main-sequence ID YOUNG STELLAR OBJECTS; STAR-FORMING REGIONS; T-TAURI STARS; MAIN-SEQUENCE STARS; SOLAR-TYPE STARS; TRAPEZIUM CLUSTER; IMAGING SURVEY; BINARY STARS; CORE; PROTOSTARS AB We present new near- and mid-IR observations of 19 Class I/flat-spectrum young stellar objects in the nearby rho Oph (d = 125 pc) and Serpens (d = 310 pc) dark clouds. These observations are part of a larger systematic infrared multiplicity survey of Class I/flat-spectrum objects in the nearest dark clouds. We find 7/19 (37% +/- 14%) of the sources surveyed to be multiple systems over a separation range of similar to150-1800 AU. This is consistent with the fraction of multiple systems found among older pre-main-sequence stars in each of the Taurus, rho Oph, Chamaeleon, Lupus, and Corona Australis star-forming regions over a similar separation range. However, solar-type main-sequence stars in the solar neighborhood have a fraction approximately one-third that of our Class I/flat-spectrum sample (11% +/- 3%). This may be attributed to evolutionary effects or environmental differences. An examination of the spectral energy distributions (SEDs) of the SVS 20 and WL 1 binaries reveals that the individual components of each source exhibit the same SED classifications, similar to what one typically finds for binary T Tauri star (TTS) systems, where the companion of a classical TTS also tends to be of the same SED type. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Haisch, KE (reprint author), NASA, Ames Res Ctr, Mail Stop 245-6, Moffett Field, CA 94035 USA. NR 54 TC 34 Z9 34 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-6256 J9 ASTRON J JI Astron. J. PD NOV PY 2002 VL 124 IS 5 BP 2841 EP 2852 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 607AL UT WOS:000178768200035 ER PT J AU Krautter, J Woodward, CE Schuster, MT Gehrz, RD Jones, TJ Belle, K Evans, A Leyers, SPS Starrfield, S Truran, J Greenhouse, MA AF Krautter, J Woodward, CE Schuster, MT Gehrz, RD Jones, TJ Belle, K Evans, A Leyers, SPS Starrfield, S Truran, J Greenhouse, MA TI Hubble Space Telescope NICMOS observations of classical nova shells SO ASTRONOMICAL JOURNAL LA English DT Article DE novae, cataclysmic variables; stars : individual (V723 Cassiopeiae=Nova cassiopeia 1995, V1974 Cygni=Nova Cygnus 1992, QU Vulpeculae=Nova Vulpecula 1984 No. 2, QV Vulpeculae=Nova Vulpecula 1987) ID INFRARED CORONAL LINES; VULPECULAE 1984; QU-VULPECULAE; NEON NOVA; EXPANSION; EVOLUTION; NO-2; NOVA-CYGNI-1992; DISCOVERY; OUTBURST AB We present results of a campaign to obtain near-infrared images of evolved classical nova shells by using the Near-Infrared Camera and Multi-Image Spectrometer (NICMOS) on the Hubble Space Telescope. Images were obtained in six filters from 1.87 to 2.37 mum. Three of our four targets, QV Vulpeculae ( Nova Vul 1987), QU Vulpeculae ( Nova Vul 1984 No. 2), and V1974 Cygni ( Nova Cyg 1992) exhibit pronounced shell emission in the narrowband Paalpha (F187N) filter. In the other five filters, the shells are only marginally detected with the exception of QU Vul, which exhibits spatially extended low surface brightness emission in the medium-band filter (F222M) centered near 2.22 mum. Spatially extended emission from V723 Cassiopeiae ( Nova Cas 1995) was not detected above the image noise in any filter. The observed ejecta geometries lend further support to the suggestion that the speed class of a nova may correlate with the shape of the shells. The NICMOS images, in combination with ground-based spectroscopic determination of the ejecta expansion velocities, enable us to estimate the expansion parallaxes for V1974 Cyg, QU Vul, and QV Vul. Of note, the expansion velocity ( in milliarcseconds per day) determined for V1974 Cyg has remained constant over the 4 year period (1993 1998) after onset of the optical thin phase. Lastly, more structures in the shell of V1974 Cyg have appeared since 1993. C1 Univ Heidelberg, Landessternwarte, D-69117 Heidelberg, Germany. Univ Minnesota, Dept Astron, Minneapolis, MN 55455 USA. Planetary Sci Inst, Astrophys Grp, Tucson, AZ 85705 USA. Univ Keele, Dept Phys & Astron, Keele ST5 5BG, Staffs, England. Univ Chicago, Dept Astron & Astrophys, Chicago, IL 60637 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Krautter, J (reprint author), Univ Heidelberg, Landessternwarte, D-69117 Heidelberg, Germany. NR 46 TC 23 Z9 24 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-6256 J9 ASTRON J JI Astron. J. PD NOV PY 2002 VL 124 IS 5 BP 2888 EP 2898 DI 10.1086/343833 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 607AL UT WOS:000178768200039 ER PT J AU Moehler, S Sweigart, AV Landsman, WB Dreizler, S AF Moehler, S Sweigart, AV Landsman, WB Dreizler, S TI Spectroscopic analyses of the "blue hook" stars in omega Centauri: A test of the late hot flasher scenario SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE stars : horizontal-branch; stars : evolution; Galaxy : globular clusters : individual : NGC 5139 ID GRAVITATIONAL LENSING EXPERIMENT; SPACE-TELESCOPE OBSERVATIONS; SUBDWARF B-STARS; GLOBULAR-CLUSTERS; POPULATION-III; WHITE-DWARFS; PHYSICAL PARAMETERS; MASS-DISTRIBUTION; VARIABLE-STARS; HELIUM FLASH AB omega Cen contains the largest population of very hot horizontal branch (HB) stars known in a globular cluster. Recent UV observations (Whitney et al. 1998; D'Cruz et al. 2000) show a significant population of hot stars below the zero-age horizontal branch ("blue hook" stars), which cannot be explained by canonical stellar evolution. Stars which suffer unusually large mass loss on the red giant branch and thus experience the helium core flash while descending the white dwarf cooling curve could populate this region. Theory predicts that these "late hot flashers" should show higher temperatures than the hottest canonical HB stars and should have helium- and carbon-rich atmospheres. We obtained and analysed medium resolution spectra of a sample of blue hook stars to derive their atmospheric parameters. The blue hook stars are indeed both hotter (T-eff greater than or equal to35000 K) and more helium-rich than classical extreme HB stars. In addition we find indications for a large enhancement of the carbon abundance relative to the cluster abundance. C1 Univ Erlangen Nurnberg, Inst Astron, Dr Remeis Sternwarte, D-96049 Bamberg, Germany. Univ Kiel, Inst Theoret Phys & Astrophys, Abt Astrophys, D-24098 Kiel, Germany. NASA, Goddard Space Flight Ctr, SSAI, Greenbelt, MD 20771 USA. Univ Tubingen, Inst Astron, D-72076 Tubingen, Germany. RP Moehler, S (reprint author), Univ Erlangen Nurnberg, Inst Astron, Dr Remeis Sternwarte, Sternwartstr 7, D-96049 Bamberg, Germany. OI Moehler, Sabine/0000-0002-4152-9643 NR 36 TC 39 Z9 39 U1 0 U2 1 PU E D P SCIENCES PI LES ULIS CEDEXA PA 7, AVE DU HOGGAR, PARC D ACTIVITES COURTABOEUF, BP 112, F-91944 LES ULIS CEDEXA, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD NOV PY 2002 VL 395 IS 1 BP 37 EP 43 DI 10.1051/0004-6361:20021248 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 611ZH UT WOS:000179048000009 ER PT J AU Rauw, G Naze, Y Gosset, E Stevens, IR Blomme, R Corcoran, MF Pittard, JM Runacres, MC AF Rauw, G Naze, Y Gosset, E Stevens, IR Blomme, R Corcoran, MF Pittard, JM Runacres, MC TI An XMM-Newton observation of the Lagoon Nebula and the very young open cluster NGC6530 SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE ISM : individual objects : M8; open clusters and associations : individual : NGC6530; stars : early-type; stars : pre-main sequence; X-rays : stars ID X-RAY-EMISSION; LARGE MAGELLANIC CLOUD; H-II REGIONS; INTERSTELLAR BUBBLES; HOURGLASS REGION; STELLAR OBJECTS; MASS-LOSS; O-STARS; SUPERBUBBLES; M8 AB We report the results of an XMM-Newton observation of the Lagoon Nebula (M8). Our EPIC images of this region reveal a cluster of point sources, most of which have optical counterparts inside the very young open cluster NGC6530. The bulk of these X-ray sources are probably associated with low and intermediate mass pre-main sequence stars. One of the sources experienced a flare-like increase of its X-ray flux making it the second brightest source in M8 after the O4 star 9 Sgr. The X-ray spectra of most of the brightest sources can be fitted with thermal plasma models with temperatures of kT similar to a few keV. Only a few of the X-ray selected PMS candidates are known to display Halpha emission and were previously classified as classical T Tauri stars. This suggests that most of the X-ray emitting PMS stars in NGC6530 are weak-line T Tauri stars. In addition to 9 Sgr, our EPIC field of view contains also a few early-type stars. The X-ray emission from HD 164816 is found to be typical for an O9.5 III-IV star. At least one of the known Herbig Be stars in NGC6530 ( LkHalpha 115) exhibits a relatively strong X-ray emission, while most of the main sequence stars of spectral type B1 and later are not detected. We also detect ( probably) diffuse X-ray emission from the Hourglass Region that might reveal a hot bubble blown by the stellar wind of Herschel 36, the ionizing star of the Hourglass Region. C1 Univ Liege, Inst Astrophys, B-4000 Liege, Sart Tilman, Belgium. Univ Birmingham, Sch Phys & Astron, Birmingham B15 2TT, W Midlands, England. Observ Royal Belgique, B-1180 Brussels, Belgium. NASA, Goddard Space Flight Ctr, USRA, HEASARC, Greenbelt, MD 20771 USA. Univ Leeds, Dept Phys & Astron, Leeds LS2 9JT, W Yorkshire, England. RP Univ Liege, Inst Astrophys, Allee 6 Aout,Bat B5C, B-4000 Liege, Sart Tilman, Belgium. EM rauw@astro.ulg.ac.be OI Naze, Yael/0000-0003-4071-9346; Pittard, Julian/0000-0003-2244-5070 NR 50 TC 33 Z9 34 U1 0 U2 0 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 1432-0746 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD NOV PY 2002 VL 395 IS 2 BP 499 EP 513 DI 10.1051/0004-6361:20021230 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 616EQ UT WOS:000179291000019 ER PT J AU Rauw, G Blomme, R Waldron, WL Corcoran, MF Pittard, JM Pollock, AMT Runacres, MC Sana, H Stevens, IR Van Loo, S AF Rauw, G Blomme, R Waldron, WL Corcoran, MF Pittard, JM Pollock, AMT Runacres, MC Sana, H Stevens, IR Van Loo, S TI A multi-wavelength investigation of the non-thermal radio emitting O-star 9 Sgr SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE radiation mechanisms : non-thermal; stars : early-type; stars : individual : 9 Sgr; stars : winds, outflows; X-rays : stars ID WOLF-RAYET STARS; ALL-SKY SURVEY; X-RAY; STELLAR WINDS; ROTATIONAL VELOCITIES; MASS-LOSS; EMISSION; BINARIES; ACCELERATION; SPECTROMETER AB We report the results of a multi-wavelength investigation of the O4 V star 9 Sgr (= HD164794). Our data include observations in the X-ray domain with XMM-Newton, in the radio domain with the VLA as well as optical spectroscopy. 9 Sgr is one of a few presumably single OB stars that display non-thermal radio emission. This phenomenon is attributed to synchrotron emission by relativistic electrons accelerated in strong hydrodynamic shocks in the stellar wind. Given the enormous supply of photospheric UV photons in the wind of 9 Sgr, inverse Compton scattering by these relativistic electrons is a priori expected to generate a non-thermal power law tail in the X-ray spectrum. Our EPIC and RGS spectra of 9 Sgr reveal a more complex situation than expected from this simple theoretical picture. While the bulk of the thermal X-ray emission from 9 Sgr arises most probably in a plasma at temperature similar to3 x 10(6) K distributed throughout the wind, the nature of the hard emission in the X-ray spectrum is less clear. Assuming a non-thermal origin, our best fitting model yields a photon index of greater than or equal to2.9 for the power law component which would imply a low compression ratio of less than or equal to1.79 for the shocks responsible for the electron acceleration. However, the hard emission can also be explained by a thermal plasma at a temperature greater than or equal to2 x 10(7) K. Our VLA data indicate that the radio emission of 9 Sgr was clearly non-thermal at the time of the XMM-Newton observation. Again, we derive a low compression ratio (1.7) for the shocks that accelerate the electrons responsible for the synchrotron radio emission. Finally, our optical spectra reveal long-term radial velocity variations suggesting that 9 Sgr could be a long-period spectroscopic binary. C1 Univ Liege, Inst Astrophys, B-4000 Liege, Belgium. Royal Observ, B-1180 Brussels, Belgium. L3 Commun Analyt Corp, Largo, MD 20774 USA. NASA, Goddard Space Flight Ctr, USRA, HEASARC, Greenbelt, MD 20771 USA. Univ Leeds, Dept Phys & Astron, Leeds LS2 9JT, W Yorkshire, England. Comp & Sci Co Ltd, Sheffield S10 3GS, S Yorkshire, England. European Space Agcy, Madrid 28080, Spain. Univ Birmingham, Sch Phys & Astron, Birmingham B15 2TT, W Midlands, England. RP Univ Liege, Inst Astrophys, Allee 6 Aout,Bat B5c, B-4000 Liege, Belgium. EM rauw@astro.ulg.ac.be RI Sana, Hugues/B-2664-2013; OI Sana, Hugues/0000-0001-6656-4130; Van Loo, Sven/0000-0003-4746-8500; Pittard, Julian/0000-0003-2244-5070 NR 67 TC 40 Z9 40 U1 0 U2 0 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 1432-0746 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD NOV PY 2002 VL 394 IS 3 BP 993 EP 1008 DI 10.1051/0004-6361:20020926 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 609CL UT WOS:000178885000027 ER PT J AU Suleimanov, VF Ghosh, KK Austin, RA Ramsey, BD AF Suleimanov, VF Ghosh, KK Austin, RA Ramsey, BD TI X-ray emission from accretion disks in active galactic nuclei SO ASTRONOMY LETTERS-A JOURNAL OF ASTRONOMY AND SPACE ASTROPHYSICS LA English DT Article DE active galactic nuclei; quasars; radio galaxies; X-ray emission; disk accretion. ID BLACK-HOLE; COMPTON REFLECTION; VERTICAL STRUCTURE; SPECTRA; QUASARS; LINE; GALAXIES; ASCA; POLARIZATION; MCG+8-11-11 AB We constructed a grid of relativistic models for standard high-relative-luminosity accretion alpha-disks around supermassive Kerr black holes (BHs) and computed X-ray spectra for their hot, effectively optically thin inner parts by taking into account general-relativity effects. They are known to be heated to high (similar to10(6)-10(9) K) temperatures and to cool down through the Comptonization of intrinsic thermal radiation. Their spectra are power laws with an exponential cutoff at high energies; i.e., they have the same shape as those observed in active galactic nuclei (AGNs). Fitting the observed X-ray spectra of AGNs with computed spectra allowed us to estimate the fundamental parameters of BHs (their mass and Kerr parameter) and accretion disks (luminosity and inclination to the line of sight) in 28 AGNs. We show that the Kerr parameter for BHs in AGNs is close to unity and that the disk inclination correlates with the Seyfert type of AGN, in accordance with the unification model of activity. The estimated BH masses M-x are compared with the masses M-rev determined by the reverberation mapping technique. For AGNs with luminosities close to the Eddington limit, these masses agree and the model under consideration may be valid for them. For low-relative-luminosity AGNs, the differences in masses increase with decreasing relative luminosity and their X-ray emission cannot be explained by this model. (C) 2002 MAIK "Nauka/Interperiodica". C1 Kazan VI Lenin State Univ, Kazan 420008, Tatarstan, Russia. NASA, G Marshall Space Flight Ctr, Dept Space Res, Huntsville, AL USA. RP Suleimanov, VF (reprint author), Kazan VI Lenin State Univ, Ul Lenina 18, Kazan 420008, Tatarstan, Russia. NR 41 TC 6 Z9 6 U1 0 U2 1 PU MAIK NAUKA/INTERPERIODICA PUBL PI MELVILLE PA C/O AMERICAN INST PHYSICS, 2 HUNTINGTON QUANDRANGLE, STE 1NO1, MELVILLE, NY 11747-4502 USA SN 1063-7737 J9 ASTRON LETT+ JI Astron. Lett.-J. Astron. Space Astrophys. PD NOV PY 2002 VL 28 IS 11 BP 745 EP 754 DI 10.1134/1.1518712 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 615TB UT WOS:000179261800003 ER PT J AU Scranton, R Johnston, D Dodelson, S Frieman, JA Connolly, A Eisenstein, DJ Gunn, JE Hui, L Jain, B Kent, S Loveday, J Narayanan, V Nichol, RC O'Connell, L Scoccimarro, R Sheth, RK Stebbins, A Strauss, MA Szalay, AS Szapudi, I Tegmark, M Vogeley, M Zehavi, I Annis, J Bahcall, NA Brinkman, J Csabai, I Hindsley, R Ivezic, Z Kim, RSJ Knapp, GR Lamb, DQ Lee, BC Lupton, RH McKay, T Munn, J Peoples, J Pier, J Richards, GT Rockosi, C Schlegel, D Schneider, DP Stoughton, C Tucker, DL Yanny, B York, DG AF Scranton, R Johnston, D Dodelson, S Frieman, JA Connolly, A Eisenstein, DJ Gunn, JE Hui, L Jain, B Kent, S Loveday, J Narayanan, V Nichol, RC O'Connell, L Scoccimarro, R Sheth, RK Stebbins, A Strauss, MA Szalay, AS Szapudi, I Tegmark, M Vogeley, M Zehavi, I Annis, J Bahcall, NA Brinkman, J Csabai, I Hindsley, R Ivezic, Z Kim, RSJ Knapp, GR Lamb, DQ Lee, BC Lupton, RH McKay, T Munn, J Peoples, J Pier, J Richards, GT Rockosi, C Schlegel, D Schneider, DP Stoughton, C Tucker, DL Yanny, B York, DG CA SDSS Collaboration TI Analysis of systematic effects and statistical uncertainties in angular clustering of galaxies from early Sloan Digital Sky Survey data SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmology : observations; large-scale structure of universe ID SURVEY PHOTOMETRIC SYSTEM; SURVEY COMMISSIONING DATA; POWER SPECTRUM; GRAVITATIONAL-INSTABILITY; LUMINOSITY FUNCTION; VARIANCE; CATALOG; EVOLUTION; W(THETA); OBJECTS AB The angular distribution of galaxies encodes a wealth of information about large-scale structure. Ultimately, the Sloan Digital Sky Survey (SDSS) will record the angular positions of order of 10(8) galaxies in five bands, adding significantly to the cosmological constraints. This is the first in a series of papers analyzing a rectangular stripe of 2.degrees5 x 90degrees from early SDSS data. We present the angular correlation function for galaxies in four separate magnitude bins on angular scales ranging from 0.degrees003 to 15degrees. Much of the focus of this paper is on potential systematic effects. We show that the final galaxy catalog with the mask accounting for regions of poor seeing, reddening, bright stars, etc. is free from external and internal systematic effects for galaxies brighter than r* = 22. Our estimator of the angular correlation function includes the effects of the integral constraint and the mask. The full covariance matrix of errors in these estimates is derived using mock catalogs with further estimates using a number of other methods. C1 Univ Chicago, Dept Astron & Astrophys, Chicago, IL 60637 USA. NASA, Fermilab Astrophys Ctr, Batavia, IL 60510 USA. Univ Pittsburgh, Dept Phys & Astron, Pittsburgh, PA 15260 USA. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. Princeton Univ Observ, Princeton, NJ 08544 USA. Columbia Univ, Dept Phys, New York, NY 10027 USA. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. Univ Penn, Dept Phys, Philadelphia, PA 19101 USA. Univ Sussex, Sussex Astron Ctr, Brighton BN1 9QJ, E Sussex, England. Carnegie Mellon Univ, Dept Phys, Pittsburgh, PA 15213 USA. Inst Adv Study, Sch Nat Sci, Princeton, NJ 08540 USA. NYU, Dept Phys, New York, NY 10003 USA. Univ Hawaii, Inst Astron, Honolulu, HI 96822 USA. Drexel Univ, Dept Phys, Philadelphia, PA 19104 USA. Apache Point Observ, Sunspot, NM 88349 USA. Eotvos Lorand Univ, Dept Phys, H-1518 Budapest, Hungary. USN, Res Lab, Remote Sensing Div, Washington, DC 20375 USA. Univ Michigan, Dept Phys, Ann Arbor, MI 48109 USA. USN Observ, Flagstaff Stn, Flagstaff, AZ 86002 USA. Penn State Univ, Dept Astron & Astrophys, University Pk, PA 16802 USA. Univ Chicago, Enrico Fermi Inst, Chicago, IL 60637 USA. RP Scranton, R (reprint author), Univ Chicago, Dept Astron & Astrophys, 5640 S Ellis Ave, Chicago, IL 60637 USA. RI Csabai, Istvan/F-2455-2012; McKay, Timothy/C-1501-2009; OI McKay, Timothy/0000-0001-9036-6150; Csabai, Istvan/0000-0001-9232-9898 NR 51 TC 178 Z9 178 U1 0 U2 4 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD NOV 1 PY 2002 VL 579 IS 1 BP 48 EP 75 DI 10.1086/342786 PN 1 PG 28 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 607XZ UT WOS:000178817200006 ER PT J AU Postman, M Lauer, TR Oegerle, W Donahue, M AF Postman, M Lauer, TR Oegerle, W Donahue, M TI The KPNO/Deeprange Distant Cluster Survey. I. The catalog and the space density of intermediate-redshift clusters SO ASTROPHYSICAL JOURNAL LA English DT Article DE catalogs; galaxies : clusters : general; large-scale structure of universe ID SPATIAL CORRELATION-FUNCTION; OPTICALLY SELECTED CLUSTERS; DIGITAL SKY SURVEY; X-RAY SURVEY; RICH CLUSTERS; GALAXY CLUSTERS; DARK-MATTER; LUMINOSITY FUNCTIONS; EVOLUTION; SAMPLE AB We have conducted an automated search for galaxy clusters within a contiguous 16 deg(2) I-band survey in the north Galactic hemisphere. A matched filter detection algorithm identifies 444 cluster candidates in the range 0.2 less than or similar to z less than or similar to 1.2. The full catalog is presented along with the results from a follow-up spectroscopic survey. The estimated redshift distribution of the cluster candidates is consistent with a constant comoving density over the range 0.2 less than or equal to z(est) less than or equal to 0.8. A decline in the cluster space density by more than a factor of 3 over this redshift range is rejected at the greater than 99.9% confidence level. We find that the space density of Lambda(cl) greater than or equal to 40 clusters in our survey lies in the range d (1.6-1.8) x 10(-5) h(75)(3) Mpc(-3), similar to1.5 times higher than the local distribution of comparably rich Abell richness class 0 clusters. The Lambda(cl) distribution is consistent with a power law. The discrepancy between the space density of Abell clusters and the clusters in this survey declines quickly as Lambda(cl) increases, suggesting that the difference at lower richness is due to significant incompleteness in the Abell catalog. A percolation analysis reveals that 10%-20% of the spectroscopically confirmed distant clusters are linked into superclusters at overdensities between 10 < delta rho/rho < 50, similar to what is seen in the local cluster distribution. This suggests that there has been little evolution of the cluster- cluster correlation length for z less than or similar to 0.5. C1 Space Telescope Sci Inst, Baltimore, MD 21218 USA. Natl Opt Astron Observ, Tucson, AZ 85726 USA. NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. RP Postman, M (reprint author), Space Telescope Sci Inst, 3700 San Martin Dr, Baltimore, MD 21218 USA. RI Donahue, Megan/B-5361-2012; Oegerle, William/C-9070-2012 NR 71 TC 39 Z9 39 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD NOV 1 PY 2002 VL 579 IS 1 BP 93 EP 126 DI 10.1086/342725 PN 1 PG 34 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 607XZ UT WOS:000178817200009 ER PT J AU Norris, JP AF Norris, JP TI Implications of the lag-luminosity relationship for unified gamma-ray burst paradigms SO ASTROPHYSICAL JOURNAL LA English DT Article DE gamma rays : bursts; gravitational waves; relativity; supernovae : general ID 25 APRIL 1998; UNUSUAL SUPERNOVA; CENTRAL ENGINES; LIGHT CURVES; SN 1998BW; EMISSION; REIONIZATION; ENERGY; DURATIONS; AFTERGLOW AB Spectral lags (tau(lag)) are deduced using a cross-correlation methodology for 1429 long (T-90 > 2 s) BATSE gamma-ray bursts (GRBs) with peak flux F-p > 0.25 photons cm(-2) s(-1), near to the BATSE trigger threshold. The lags are modeled as a power-law function of peak flux with limit parameters for the lag extrema. Lag model errors are assigned via a novel decimation procedure, drawing from the observed lag distribution with Fp and lag as governing parameters. The model parameters were adjusted within a five-dimensional grid to achieve best agreement with the observed distribution in the F-p-tau(lag) plane. Assuming a two-branch lag-luminosity relationship, the lags are self-consistently corrected for cosmological effects to yield distributions in luminosity, distance, and redshift. The results have several consequences for GRB populations and for unified gamma-ray/afterglow scenarios that would account for afterglow break times and gamma-ray spectral evolution in terms of jet opening angle, viewing angle, or a pro led jet with variable Lorentz factor. A component of the burst sample is identified those with few, wide pulses, lags of a few tenths to several seconds, and soft spectra whose log N-log F-p distribution approximates a -3/2 power law, suggesting homogeneity and relatively nearby sources. The proportion of long-lag bursts increases from negligible among bright BATSE bursts to similar to50% at trigger threshold. Bursts with very long lags, similar to1-2s < tau(lag) < 10 s, show a tendency to concentrate near the supergalactic plane with a quadrupole moment of roughly -0.10 +/- 0.04. GRB 980425 ( SN 1998bw) is a member of this subsample of similar to90 bursts with estimated distances less than 100 Mpc. The frequency of the observed ultralow-luminosity bursts is similar to1/4 that of Type Ib/c supernovae (SNe Ib/c) within the same volume. The model lags predict a power-law scaling relation for the ultralow-luminosity GRBs, dN(sen)/dL similar to L-1, flatter than expected (dN(sen)/dL similar to L-1/6) if viewing angle with respect to the jet axis alone governed perceived luminosity. For high-luminosity bursts, the modeling yields dN(vol)/dL similar to L-1.8, similar to expectations for viewing angle scenarios (dN(vol)/dL similar to L-2); however, if luminosity decreases off-axis, L similar to theta(view)(-lambda) (lambda > 0), then overproduction of low-luminosity bursts results. Thus, the relativistic kinematic factor as the dominant component for the dynamic range in GRB luminosities is not favored. The variable beaming fraction scenario, with constant luminosity across the jet cone, can fit the high-luminosity bursts with a fairly at distribution in jet cone solid angle, dN (Omega(jet))/dOmega(jet) proportional to Omega(jet)(-0.2) jet; for the ultralow-luminosity bursts a distribution that increases is required, dN (Omega(jet))/dOmega(jet) proportional to Omega(jet)(0.5). Jets with variable luminosity profiles viewed at a range of angles can also reproduce the observed luminosity distributions, such that L similar to theta(view)(-2.5) and L similar to theta(view)(-1.3) view for high- and ultralow-luminosity regimes, respectively. Approximately 1/300 of the universal SN Ib/c population would be required to produce GRBs at cosmological distances, with a rate of 1 x 10(6) to a few times 10(6) yr(-1). The modeled redshift distribution for GRBs peaks at z similar to 10, with large uncertainty. C1 NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Norris, JP (reprint author), NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Code 661, Greenbelt, MD 20771 USA. NR 71 TC 161 Z9 163 U1 0 U2 5 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD NOV 1 PY 2002 VL 579 IS 1 BP 386 EP 403 DI 10.1086/342747 PN 1 PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 607XZ UT WOS:000178817200031 ER PT J AU Petre, R Kuntz, KD Shelton, RL AF Petre, R Kuntz, KD Shelton, RL TI The X-ray structure and spectrum of the pulsar wind nebula surrounding PSR B1853+01 in W44 SO ASTROPHYSICAL JOURNAL LA English DT Article DE ISM : individual (W44); pulsars : individual (PSR B1853+01); supernova remnants; X-rays : general ID SUPERNOVA REMNANT W44; IC-443; MODEL; DISCOVERY; 3C-58; RADIO AB We present the result of a Chandra ACIS observation of the pulsar PSR B1853+01 and its associated pulsar wind nebula (PWN), embedded in the supernova remnant W44. A hard-band ACIS map cleanly distinguishes the PWN from the thermal emission of W44. The nebula is extended in the north-south direction, with an extent about half that of the radio emission. Morphological differences between the X-ray and radio images are apparent. Spectral fitting reveals a clear difference in spectral index between the hard emission from PSR B1853+01 (Gamma similar to 1.4) and the extended nebula (Gamma similar to 2.2). The more accurate values for the X-ray flux and spectral index are used to refine estimates for PWN parameters, including magnetic field strength, the average Lorentz factor gamma of the particles in the wind, the magnetization parameter sigma, and the ratio k of electrons to other particles. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Johns Hopkins Univ, Henry A Rowland Dept Phys & Astron, Baltimore, MD 21218 USA. RP Petre, R (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 25 TC 43 Z9 43 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD NOV 1 PY 2002 VL 579 IS 1 BP 404 EP 410 DI 10.1086/342672 PN 1 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 607XZ UT WOS:000178817200032 ER PT J AU Mennesson, B Perrin, G Chagnon, G du Foresto, VC Ridgway, S Merand, A Salome, P Borde, P Cotton, W Morel, S Kervella, P Traub, W Lacasse, M AF Mennesson, B Perrin, G Chagnon, G du Foresto, VC Ridgway, S Merand, A Salome, P Borde, P Cotton, W Morel, S Kervella, P Traub, W Lacasse, M TI Evidence for very extended gaseous layers around O-rich Mira variables and M giants SO ASTROPHYSICAL JOURNAL LA English DT Article DE circumstellar matter; instrumentation : interferometers; stars : atmospheres; stars : variables : other; techniques : interferometric ID MASS-LOSS RATES; ANGULAR DIAMETER; R-LEONIS; INTERFEROMETRIC OBSERVATIONS; DIFFRACTION LIMIT; 11 MICRONS; COOL STARS; CETI; SPECTROSCOPY; ATMOSPHERE AB Nine bright O-rich Mira stars and five semiregular variable cool M giants have been observed with the Infrared and Optical Telescope Array (IOTA) interferometer in both K' (similar to2.15 mum) and L' (similar to3.8 mum) broadband filters, in most cases at very close variability phases. All of the sample Mira stars and four of the semiregular M giants show strong increases, from similar or equal to20% to similar or equal to100%, in measured uniform-disk (UD) diameters between the K' and L' bands. (A selection of hotter M stars does not show such a large increase.) There is no evidence that K' and L/ broadband visibility measurements should be dominated by strong molecular bands, and cool expanding dust shells already detected around some of these objects are also found to be poor candidates for producing these large apparent diameter increases. Therefore, we propose that this must be a continuum or pseudocontinuum opacity effect. Such an apparent enlargement can be reproduced using a simple two-component model consisting of a warm ( 1500 2000 K), extended (up to similar or equal to3 stellar radii), optically thin (tau similar to 0.5) layer located above the classical photosphere. The Planck weighting of the continuum emission from the two layers will suffice to make the L' UD diameter appear larger than the K' UD diameter. This two-layer scenario could also explain the observed variation of Mira UD diameters versus infrared wavelength outside of strong absorption bands as already measured inside the H, K, L, and N atmospheric windows. This interpretation is consistent with the extended molecular gas layers (H2O, CO, etc.) inferred around some of these objects from previous IOTA K'-band interferometric observations obtained with the Fiber Linked Unit for Optical Recombination (FLUOR) and from Infrared Space Observatory and high-resolution ground-based FTS infrared spectra. The two-component model has immediate implications. For example, the Mira photosphere diameters are smaller than previously recognized this certainly implies higher effective temperatures, and it may favor fundamental mode pulsation. Also, the UD model fails generally to represent the brightness distribution and has very limited applicability for Mira stars. The presence of a very extended gas layer extending up to 3 stellar radii seems now well established on a fair sample of asymptotic giant branch stars ranging from late-type giants to long-period variables, with some probable impact on stellar model atmospheres and mass-loss mechanisms. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Lab Etud Spatiales & Instrumentat Astrophys, F-92195 Meudon, France. Natl Opt Astron Observ, Tucson, AZ 85719 USA. Natl Radio Astron Observ, Charlottesville, VA 22903 USA. European So Observ, D-85748 Garching, Germany. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Mennesson, B (reprint author), CALTECH, Jet Prop Lab, MS 306-388,4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 40 TC 79 Z9 79 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD NOV 1 PY 2002 VL 579 IS 1 BP 446 EP 454 DI 10.1086/342671 PN 1 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 607XZ UT WOS:000178817200037 ER PT J AU Laughlin, G Chambers, J Fischer, D AF Laughlin, G Chambers, J Fischer, D TI A dynamical analysis of the 47 Ursae Majoris planetary system SO ASTROPHYSICAL JOURNAL LA English DT Article DE methods : numerical; planetary systems; stars : individual (47 Ursae Majoris) ID MAIN-SEQUENCE STARS; UPSILON-ANDROMEDAE; SOLAR-SYSTEM; TERRESTRIAL PLANETS; STABILITY ANALYSIS; HABITABLE ZONES; ASTEROID BELT; V-ANDROMEDAE; BODIES; PROTOPLANETS AB Thirteen years of Doppler velocity measurements have revealed the presence of two planets orbiting the star 47 Ursae Majoris on low-eccentricity orbits. A two-Keplerian fit to the radial velocity data suggests that the inner planet has a period P-b = 1089.0 +/- 2.9 days and a nominal [sin (i) = 1] mass M sin i = 2.54 M-Jup, while the outer planet has a period P-c = 2594 +/- 90 days and a mass M sin i = 0.76 M-Jup. These mass and period ratios suggest a possible kinship to the Jupiter-Saturn pair in our own solar system. We explore the current dynamical state of this system with numerical integrations, and compare the results with analytic secular theory. We find that the planets in the system are likely participating in a secular resonance in which the difference in the longitudes of pericenter librates around zero. Alternately, it is possible that the system is participating in the 7:3 mean motion resonance ( in which case apsidal alignment does not occur). Using a self-consistent fitting procedure in conjunction with numerical integrations, we show that stability considerations restrict the mutual inclination between the two planets to similar to40degrees or less, and that this result is relatively insensitive to the total mass of the two planets. We present hydrodynamical simulations which measure the torques exerted on the planets by a hypothesized external protoplanetary disk. We show that planetary migration in response to torques from the disk may have led to capture of the system into a 7 : 3 mean-motion resonance, although it is unclear how the eccentricities of the planets would have been damped after capture occurred. We show that Earth-mass planets can survive for long periods in some regions of the habitable zone of the nominal coplanar system. A set of planetary accretion calculations, however, shows that it is unlikely that large terrestrial planets can form in the 47 UMa habitable zone. C1 Univ Calif Santa Cruz, Univ Calif Observ, Lick Observ, Dept Astron, Santa Cruz, CA 95064 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA. RP Laughlin, G (reprint author), Univ Calif Santa Cruz, Univ Calif Observ, Lick Observ, Dept Astron, Santa Cruz, CA 95064 USA. OI Fischer, Debra/0000-0003-2221-0861 NR 42 TC 57 Z9 59 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD NOV 1 PY 2002 VL 579 IS 1 BP 455 EP 467 DI 10.1086/342746 PN 1 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 607XZ UT WOS:000178817200038 ER PT J AU Windhorst, RA Taylor, VA Jansen, RA Odewahn, SC Chiarenza, CAT Conselice, CJ de Grus, R de Jong, RS MacKenty, JW Eskridge, PB Frogel, JA Gallagher, JS Hibbard, JE Matthews, LD O'Connell, RW AF Windhorst, RA Taylor, VA Jansen, RA Odewahn, SC Chiarenza, CAT Conselice, CJ de Grus, R de Jong, RS MacKenty, JW Eskridge, PB Frogel, JA Gallagher, JS Hibbard, JE Matthews, LD O'Connell, RW TI A Hubble Space Telescope survey of the mid-ultraviolet morphology of nearby galaxies SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Review DE galaxies : elliptical and lenticular, cD; galaxies : interactions; galaxies : irregular; galaxies : peculiar; galaxies : spiral; ultraviolet : galaxies ID ULTRALUMINOUS INFRARED GALAXIES; RESOLUTION CO OBSERVATIONS; BRIGHT STARBURST GALAXIES; MERGER REMNANT NGC-3921; YOUNG GLOBULAR-CLUSTERS; BARRED SPIRAL GALAXIES; STAR-FORMING GALAXIES; LDSS REDSHIFT SURVEYS; MEDIUM DEEP SURVEY; H-II REGIONS AB We present a systematic imaging survey of 37 nearby galaxies observed with the Hubble Space Telescope (HST) Wide Field and Planetary Camera 2 (WFPC2) in the mid-UV F300W filter, centered at 2930 Angstrom, as well as in the I-band (F814W) filter at 8230 Angstrom. Eleven of these galaxies were also imaged in the F255W filter, centered at 2550 Angstrom. Our sample is carefully selected to include galaxies of sufficiently small radius and high predicted mid-UV surface brightness to be detectable with WFPC2 in one orbit and covers a wide range of Hubble types and inclinations. The mid-UV (2000-3200 Angstrom) spans the gap between ground-based UBVR(IJHK) images, which are available or were acquired for the current study, and far-UV images available from the Astro/UIT missions for 15 galaxies in our sample. The first qualitative results from our study are as follows: 1. Early-type galaxies show a significant decrease in surface brightness going from the red to the mid-UV, reflecting the absence of a dominant young stellar population and in some cases the presence of significant (central) dust lanes. Galaxies that are early types in the optical show a variety of morphologies in the mid-UV that can lead to a different morphological classification, although not necessarily as later type. Some early-type galaxies become dominated by a blue nuclear feature or a point source in the mid-UV, e.g., as a result of the presence of a Seyfert nucleus or a LINER. This is in part due to our mid-UV surface brightness selection, but it also suggests that part of the strong apparent evolution of weak AGNs in early-type galaxies may be due to surface brightness dimming of their UV-faint stellar population, which renders the early-type host galaxies invisible at intermediate to higher redshifts. 2. About half of the mid-type spiral and star-forming galaxies appear as a later morphological type in the mid-UV, as Astro/UIT also found primarily in the far-UV. Sometimes these differences are dramatic (e.g., NGC 6782 shows a spectacular ring of hot stars in the mid-UV). However, not all mid-type spiral galaxies look significantly different in the mid-UV. Their mid-UV images show a considerable range in the scale and surface brightness of individual star-forming regions. Almost without exception, the mid-type spirals in our sample have their small bulges bisected by a dust lane, which often appears to be connected to the inner spiral arm structure. 3. The majority of the heterogeneous subset of late-type, irregular, peculiar, and merging galaxies display F300W morphologies that are similar to those seen in F814W, but with important differences due to recognizable dust features absorbing the bluer light and to hot stars, star clusters, and star formation "ridges" that are bright in the mid-UV. Less than one-third of the galaxies classified as late type in the optical appear sufficiently different in the mid-UV to result in a different classification. Our HST mid-UV survey of nearby galaxies shows that, when observed in the rest-frame mid-UV, early- to mid-type galaxies are more likely to be misclassified as later types than late-type galaxies are to be misclassified as earlier types. This is because the later type galaxies are dominated by the same young and hot stars in all filters from the mid-UV to the red and so have a smaller "morphological K-correction" than true earlier type galaxies. The morphological K-correction can thus explain part, but certainly not all, of the excess faint blue late-type galaxies seen in deep HST fields. C1 Arizona State Univ, Dept Phys & Astron, Tempe, AZ 85287 USA. CALTECH, Dept Astron, Pasadena, CA 91125 USA. Univ Cambridge, Inst Astron, Cambridge CB3 0HA, England. Minnesota State Univ, Dept Phys & Astron, Mankato, MN 56003 USA. NASA, Headquarters, Washington, DC 20546 USA. Univ Wisconsin, Dept Astron, Madison, WI 53706 USA. Natl Radio Astron Observ, Charlottesville, VA 22903 USA. Ctr Astrophys, Cambridge, MA 02138 USA. Univ Virginia, Dept Astron, Charlottesville, VA 22903 USA. Space Telescope Sci Inst, Baltimore, MD 21218 USA. Ohio State Univ, Dept Astron, Columbus, OH 43210 USA. RP Windhorst, RA (reprint author), Arizona State Univ, Dept Phys & Astron, Box 871504, Tempe, AZ 85287 USA. RI Conselice, Christopher/B-4348-2013; OI Conselice, Christopher/0000-0003-1949-7638; de Grijs, Richard/0000-0002-7203-5996 NR 185 TC 85 Z9 85 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0067-0049 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD NOV PY 2002 VL 143 IS 1 BP 113 EP 158 DI 10.1086/341556 PG 46 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 607HN UT WOS:000178786200005 ER PT J AU Pellerin, A Fullerton, AW Robert, C Howk, JC Hutchings, JB Walborn, NR Bianchi, L Crowther, PA Sonneborn, G AF Pellerin, A Fullerton, AW Robert, C Howk, JC Hutchings, JB Walborn, NR Bianchi, L Crowther, PA Sonneborn, G TI An atlas of Galactic OB spectra observed with the Far Ultraviolet Spectroscopic Explorer SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article DE atlases; stars : early-type; ultraviolet : stars ID EARLY-TYPE STARS; INTERSTELLAR MOLECULAR-HYDROGEN; SPACE DISTRIBUTION; ORFEUS-SPAS; CLASSIFICATION; PERFORMANCE; MISSION; UV; COPERNICUS; LINES AB An atlas of far-ultraviolet spectra of 45 Galactic OB stars observed with the Far Ultraviolet Spectroscopic Explorer is presented. The atlas covers the wavelength region between 912 and 1185 Angstrom with an effective spectral resolution of 0.12 Angstrom. Systematic trends in the morphology and strength of stellar features are discussed. Particular attention is drawn to the variations of the C III lambda1176, S IV lambdalambda1063, 1073, and P lambdalambda1118, 1128 line profiles as a function of temperature and luminosity class; and the lack of a luminosity dependence associated with O VI lambdalambda1032, 1038. Numerous interstellar lines are also identified. C1 Univ Laval, Dept Phys Genie Phys & Opt, Ste Foy, PQ G1K 7P4, Canada. Univ Laval, Observ Mt Megant, Ste Foy, PQ G1K 7P4, Canada. Univ Victoria, Dept Phys & Astron, Victoria, BC V8W 3P6, Canada. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. Natl Res Council Canada, Herzberg Inst Astrophys, Victoria, BC V8X 4M6, Canada. Space Telescope Sci Inst, Baltimore, MD 21218 USA. UCL, Dept Phys & Astron, London WC1E 6BT, England. NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. RP Univ Laval, Dept Phys Genie Phys & Opt, Ste Foy, PQ G1K 7P4, Canada. RI Howk, Jay/D-2577-2013; OI Crowther, Paul/0000-0001-6000-6920 NR 45 TC 49 Z9 49 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0067-0049 EI 1538-4365 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD NOV PY 2002 VL 143 IS 1 BP 159 EP 200 DI 10.1086/342268 PG 42 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 607HN UT WOS:000178786200006 ER PT J AU Calder, AC Fryxell, B Plewa, T Rosner, R Dursi, LJ Weirs, VG Dupont, T Robey, HF Kane, JO Remington, BA Drake, RP Dimonte, G Zingale, M Timmes, FX Olson, K Ricker, P MacNeice, P Tufo, HM AF Calder, AC Fryxell, B Plewa, T Rosner, R Dursi, LJ Weirs, VG Dupont, T Robey, HF Kane, JO Remington, BA Drake, RP Dimonte, G Zingale, M Timmes, FX Olson, K Ricker, P MacNeice, P Tufo, HM TI On validating an astrophysical simulation code SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Review DE hydrodynamics; instabilities; methods : numerical; shock waves ID RAYLEIGH-TAYLOR INSTABILITY; PIECEWISE-PARABOLIC METHOD; CORE-COLLAPSE SUPERNOVA; NEUTRON-STAR ENVELOPES; OMEGA-LASER-SYSTEM; X-RAY-BURSTS; WHITE-DWARFS; CLASSICAL NOVAE; 2-DIMENSIONAL HYDRODYNAMICS; 3-DIMENSIONAL SIMULATIONS AB We present a case study of validating an astrophysical simulation code. Our study focuses on validating FLASH, a parallel, adaptive-mesh hydrodynamics code for studying the compressible, reactive flows found in many astrophysical environments. We describe the astrophysics problems of interest and the challenges associated with simulating these problems. We describe methodology and discuss solutions to difficulties encountered in verification and validation. We describe verification tests regularly administered to the code, present the results of new verification tests, and outline a method for testing general equations of state. We present the results of two validation tests in which we compared simulations to experimental data. The first is of a laser-driven shock propagating through a multilayer target, a configuration subject to both Rayleigh-Taylor and Richtmyer-Meshkov instabilities. The second test is a classic Rayleigh-Taylor instability, where a heavy fluid is supported against the force of gravity by a light fluid. Our simulations of the multilayer target experiments showed good agreement with the experimental results, but our simulations of the Rayleigh-Taylor instability did not agree well with the experimental results. We discuss our findings and present results of additional simulations undertaken to further investigate the Rayleigh-Taylor instability. C1 Univ Chicago, Ctr Astrophys Thermonucl Flashes, Chicago, IL 60637 USA. Univ Chicago, Dept Astron & Astrophys, Chicago, IL 60637 USA. Univ Chicago, Enrico Fermi Inst, Chicago, IL 60637 USA. Nicholas Copernicus Astron Ctr, PL-00716 Warsaw, Poland. Univ Chicago, Dept Comp Sci, Chicago, IL 60637 USA. Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Univ Michigan, Dept Atmospher Ocean & Space Sci, Ann Arbor, MI 48105 USA. Univ Calif Santa Cruz, Dept Astron & Astrophys, Santa Cruz, CA 95064 USA. NASA, Goddard Space Flight Ctr, UMBC GEST Ctr, Greenbelt, MD 20771 USA. RP Univ Chicago, Ctr Astrophys Thermonucl Flashes, Chicago, IL 60637 USA. RI Plewa, Tomasz/C-1470-2010; Calder, Alan/E-5348-2011; MacNeice, Peter/F-5587-2012; Drake, R Paul/I-9218-2012; OI Plewa, Tomasz/0000-0002-1762-2565; Drake, R Paul/0000-0002-5450-9844; Zingale, Michael/0000-0001-8401-030X; Dursi, Jonathan/0000-0002-4697-798X NR 138 TC 132 Z9 133 U1 2 U2 14 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0067-0049 EI 1538-4365 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD NOV PY 2002 VL 143 IS 1 BP 201 EP 229 DI 10.1086/342267 PG 29 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 607HN UT WOS:000178786200007 ER PT J AU Bhatia, AK Doschek, GA Eissner, W AF Bhatia, AK Doschek, GA Eissner, W TI Atomic data and spectral line intensities for Fe XI SO ATOMIC DATA AND NUCLEAR DATA TABLES LA English DT Article ID CROSS-SECTIONS; EXCITATION AB Electron impact collision strengths and spontaneous radiative decay rates are calculated for Fe XI. The data pertain to the 96 levels of the configurations 3s(2)3p(4), 3s3p(5), 3s(2)3p(3)3d, 3p(6), 3s(2)3p(3)4s, and 3s(2)3p(3)4d. Collision strengths are calculated at 10 incident electron energies: 1.0, 3.4, 6.0, 12.0, 15.0, 30.0, 45.0, 60.0, 75.0, and 90.0 Ry. These atomic data are generated to support the interpretation of spectra of astrophysical objects, which frequently contain emission lines from Fe XI and similar ions. This work supplements previous work published on Fe XI by extending the calculation of collision strengths and radiative decay rates to levels within n = 4 configurations. Relative spectral line intensities are calculated for all astrophysically important transitions. These are obtained by computing the excitation rate coefficients (cm(3) s(-1)), i.e., the collision strengths integrated over a Maxwellian electron distribution, and then solving the equations of detailed balance for the populations of the 96 energy levels, assuming a collisional excitation model and an electron temperature of 1.3 x 10(6) K. This temperature is typical for Fe XI when formed at equilibrium by collisional ionization and recombination. Using the excitation rate coefficients and the radiative decay rates, level populations are computed for several electron densities. The calculation of line intensities and level populations includes proton excitation because hydrogen is the most abundant element in astrophysical plasmas relevant to Fe XI emission. (C) 2002 Elsevier Science (USA). C1 Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. USN, Res Lab, EO Hulburt Ctr Space Res, Washington, DC 20375 USA. Inst Theoret Phys, Peilinst, D-70550 Stuttgart, Germany. RP Bhatia, AK (reprint author), Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. NR 15 TC 11 Z9 11 U1 0 U2 0 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0092-640X J9 ATOM DATA NUCL DATA JI Atom. Data Nucl. Data Tables PD NOV PY 2002 VL 82 IS 2 BP 211 EP 255 DI 10.1006/adnd.2002.0885 PG 45 WC Physics, Atomic, Molecular & Chemical; Physics, Nuclear SC Physics GA 627JT UT WOS:000179930600002 ER PT J AU Kraft, NO Inoue, N Mizuno, K Ohshima, H Murai, T Sekiguchi, C AF Kraft, NO Inoue, N Mizuno, K Ohshima, H Murai, T Sekiguchi, C TI Physiological changes, sleep, and morning mood in an isolated environment SO AVIATION SPACE AND ENVIRONMENTAL MEDICINE LA English DT Article DE space-analog environment; catecholamines; stress; sleep; isolation ID PLASMA NOREPINEPHRINE; CATECHOLAMINES; EXCRETION AB Background: Previous isolation studies have shown increased 24-h urine volumes and body weight gains in subjects. This project examined those and other physiological variables in relationship to sleep motor activity, subjective sleep quality, mood, and complaints during confinement. Methods: Six male and two female subjects lived for 7 d in the National Space Development Agency of Japan's isolation chamber, which simulates the interior of the Japanese Experiment Module. Each 24-h period included 6 h of sleep, 3 meals, and 20 min of exercise. Each morning, subjects completed Sleep Sensation and Complaint Index questionnaires. Catecholamine and creatinine excretion, urine volume, and body weight were measured on the 2 d before and 2 d after confinement, and sleep motor activity was measured during confinement. Results: Confinement produced no significant change in body weight, urine volume, or questionnaire results, In contrast, epinephrine, norepinephrine, and sleep motor activity exhibited significant differences during confinement (p<0.05). Higher nocturnal norepinephrine excretion correlated with higher sleep motor activity. Conclusion: The 24-h epinephrine values were slightly higher than normal throughout the experiment, but lower than for subjects working under time-stress. High sympathetic activity (as indicated by norepinephrine) may have interfered with sleep. C1 NASA, Ames Res Ctr, Human Factor Res & Technol Div, Moffett Field, CA 94035 USA. Natl Space Dev Agcy Japan, Med Res & Operat Off, Tsukuba, Ibaraki, Japan. RP Kraft, NO (reprint author), NASA, Ames Res Ctr, Human Factor Res & Technol Div, Mail Stop 262-4, Moffett Field, CA 94035 USA. NR 18 TC 5 Z9 5 U1 0 U2 1 PU AEROSPACE MEDICAL ASSOC PI ALEXANDRIA PA 320 S HENRY ST, ALEXANDRIA, VA 22314-3579 USA SN 0095-6562 J9 AVIAT SPACE ENVIR MD JI Aviat. Space Environ. Med. PD NOV PY 2002 VL 73 IS 11 BP 1089 EP 1093 PG 5 WC Public, Environmental & Occupational Health; Medicine, General & Internal; Sport Sciences SC Public, Environmental & Occupational Health; General & Internal Medicine; Sport Sciences GA 611MM UT WOS:000179021500007 PM 12433232 ER PT J AU Cox, SP Martell, SJD Walters, CJ Essington, TE Kitchell, JF Boggs, C Kaplan, I AF Cox, SP Martell, SJD Walters, CJ Essington, TE Kitchell, JF Boggs, C Kaplan, I TI Reconstructing ecosystem dynamics in the central Pacific Ocean, 1952-1998. I. Estimating population biomass and recruitment of tunas and billfishes SO CANADIAN JOURNAL OF FISHERIES AND AQUATIC SCIENCES LA English DT Article ID AGE-STRUCTURED MODEL; STRATEGIES AB Commercial yield of tunas in the central Pacific increased several fold between 1952 and 1998. We developed age-structured production models that incorporate information from multiple fisheries to estimate population biomass and recruitment trends of tunas (Thunnus alalunga, Thunnus albacares, Thunnus obesus, and Katsuwonus pelamis) and billfish in the central north Pacific (0degreesN to 40degreesN and 130degreesE to 150degreesW). Our results suggest that all tuna stocks remain above 40% of 1950s levels, whereas blue marlin (Makaira nigricans) declined to 21% and swordfish (Xiphias gladius) to 56%. Estimated biomasses of juvenile bigeye (T obsesus) and yellowfin (T albacares) tuna increased to 112 and 129%, respectively, of 1950s levels. Juvenile albacore (T alalunga) decreased during the 1970s and 1980s but recovered to historical highs (121%) in recent years. Skipjack (K. pelamis) remained relatively stable between 1952 and 1980, declined by 35% between 1981 and 1990, and then increased to 68% of 1950s levels. These changes generally represent decreases in top predators and increases in small tunas, which make up their prey. Application of stock assessment methods set in a food web context provides an important step toward developing a method that recognizes fishery exploitation as a component of ecosystem dynamics. C1 Univ Wisconsin, Ctr Limnol, Madison, WI 53706 USA. SUNY Stony Brook, Marine Sci Res Ctr, Stony Brook, NY 11794 USA. Univ British Columbia, Fisheries Ctr, Vancouver, BC V6T 1Z4, Canada. NOAA, Natl Marine Fisheries Serv, SW Fisheries Sci Ctr, Honolulu, HI 96822 USA. RP Cox, SP (reprint author), Simon Fraser Univ, Sch Resource & Environm Management, 8888 Univ Dr, Burnaby, BC V5A 1S6, Canada. RI Walters, Carl/D-5714-2012; Cox, Sean/I-5374-2012 NR 27 TC 35 Z9 36 U1 0 U2 9 PU NATL RESEARCH COUNCIL CANADA PI OTTAWA PA RESEARCH JOURNALS, MONTREAL RD, OTTAWA, ONTARIO K1A 0R6, CANADA SN 0706-652X J9 CAN J FISH AQUAT SCI JI Can. J. Fish. Aquat. Sci. PD NOV PY 2002 VL 59 IS 11 BP 1724 EP 1735 DI 10.1139/F02-137 PG 12 WC Fisheries; Marine & Freshwater Biology SC Fisheries; Marine & Freshwater Biology GA 639JX UT WOS:000180626000003 ER PT J AU Cox, SP Essington, TE Kitchell, JF Martell, SJD Walters, CJ Boggs, C Kaplan, I AF Cox, SP Essington, TE Kitchell, JF Martell, SJD Walters, CJ Boggs, C Kaplan, I TI Reconstructing ecosystem dynamics in the central Pacific Ocean, 1952-1998. II. A preliminary assessment of the trophic impacts of fishing and effects on tuna dynamics SO CANADIAN JOURNAL OF FISHERIES AND AQUATIC SCIENCES LA English DT Article ID NATURAL MORTALITY; BIOMASS AB Pelagic fisheries in the Pacific Ocean target both large (Thunnus spp.) and small tunas (juveniles of Thunnus spp; Katsuwonus pelamis) but also take billfishes (Xiphias gladius, Makaira spp., Tetrapturus spp., Istiophorus platypterus) and sharks (Prionace glauca, Alopias superciliosus, Isurus oxyrinchus, Carcharhinus longimanus, Galeocerdo cuvieri) as bycatch. We developed a multispecies model using the Ecopath with Ecosim software that incorporated time-series estimates of biomass, fishing mortality, and bycatch rates (1952-1998) to evaluate the relative contributions of fishing and trophic impacts on tuna dynamics in the central Pacific (0degreesN to 40degreesN and 130degreesE to 150degreesW). The Ecosim model reproduced the observed trends in abundance indices and biomass estimates for most large tunas and billfishes. A decline in predation mortality owing to depletion of large predators was greatest for small yellowfin tuna and could possibly account for apparent increases in biomass. For other tunas, however, predicted changes in predation mortality rates were small (small bigeye) or were overwhelmed by much larger increases in fishing mortality (skipjack and small albacore). Limited evidence of trophic impacts associated with declining apex predator abundance likely results from the difficulties of applying detailed trophic models to open ocean systems in which ecological and fishery data uncertainties are large. C1 Univ Wisconsin, Ctr Limnol, Madison, WI 53706 USA. SUNY Stony Brook, Marine Sci Res Ctr, Stony Brook, NY 11794 USA. Univ British Columbia, Fisheries Ctr, Vancouver, BC V6T 1Z4, Canada. NOAA, Natl Marine Fisheries Serv, SW Fisheries Sci Ctr, Honolulu, HI 96822 USA. RP Cox, SP (reprint author), Simon Fraser Univ, Sch Resource & Environm Management, 8888 Univ Dr, Burnaby, BC V5A 1S6, Canada. EM spcox@sfu.ca RI Walters, Carl/D-5714-2012; Cox, Sean/I-5374-2012 NR 24 TC 97 Z9 102 U1 3 U2 27 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 NOV PY 2002 VL 59 IS 11 BP 1736 EP 1747 DI 10.1139/F02-138 PG 12 WC Fisheries; Marine & Freshwater Biology SC Fisheries; Marine & Freshwater Biology GA 639JX UT WOS:000180626000004 ER PT J AU Davis, MW AF Davis, MW TI Key principles for understanding fish bycatch discard mortality SO CANADIAN JOURNAL OF FISHERIES AND AQUATIC SCIENCES LA English DT Article ID POLLOCK THERAGRA-CHALCOGRAMMA; WALLEYE POLLOCK; TRAWL FISHERIES; OTTER-TRAWL; BY-CATCH; COD-END; SURVIVAL; SABLEFISH; LIGHT; LONGLINE AB The mortality of discarded fish bycatch is an important issue in fisheries management and, because it is generally unmeasured, represents a large source of uncertainty in estimates of fishing mortality worldwide. Development of accurate measures of discard mortality requires fundamental knowledge, based on principles of bycatch stressor action, of why discarded fish die. To date, discard mortality studies in the field have focused on capture stressors. Recent laboratory discard experiments have demonstrated the significant role of environmental factors, size- and species-related sensitivity to stressors, and interactions of stressors, which increase mortality. In addition, delayed mortality was an important consideration in experimental design. The discard mortality problem is best addressed through a combination of laboratory investigation of classes of bycatch stressors to develop knowledge of key principles of bycatch stressor action and field experiments under realistic fishing conditions to verify our understanding and make predictions of discard mortality. This article makes the case for a broader ecological perspective on discard mortality that includes a suite of environmental and biological factors that may interact with capture stressors to increase stress and mortality. C1 Oregon State Univ, Hatfield Marine Sci Ctr, Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr, Newport, OR 97365 USA. RP Davis, MW (reprint author), Oregon State Univ, Hatfield Marine Sci Ctr, Natl Marine Fisheries Serv, Alaska Fisheries Sci Ctr, Newport, OR 97365 USA. NR 64 TC 203 Z9 208 U1 9 U2 49 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 NOV PY 2002 VL 59 IS 11 BP 1834 EP 1843 DI 10.1139/F02-139 PG 10 WC Fisheries; Marine & Freshwater Biology SC Fisheries; Marine & Freshwater Biology GA 639JX UT WOS:000180626000012 ER PT J AU Zhang, FP Dong, D Cheng, ZY Cheng, MK Huang, C AF Zhang, FP Dong, D Cheng, ZY Cheng, MK Huang, C TI Seasonal vertical crustal motions in China detected by GPS SO CHINESE SCIENCE BULLETIN LA English DT Article DE crustal movement; seasonal altitude variation; GPS; mass loading redistribution ID SPACE-GEODESY; SURFACE; WATER; DISPLACEMENTS; GRAVITY; FIELD; OCEAN AB By analyzing daily continuous data of Chinese Global Positioning System (GPS) fiducial network with 25 sites from 1999 to 2001, seasonal altitude variations with amplitude of 3-10 mm are detected. Most part of the variations can be explained by the seasonal vertical crustal movements caused by atmospheric pressure variation and mass loading redistribution of non-tidal ocean loading, snow, and soil moisture. Nevertheless, there exists a systematic discrepancy between GPS deduced result and the counterpart predicted by combining various geophysical sources. Much longer time series of GPS site coordinates and further studies are still needed to give out a reasonable interpretation for this discrepancy. C1 Chinese Acad Sci, United Ctr Astrogeodynam Res, Natl Astron Observ, Shanghai Astron Observ, Shanghai 200030, Peoples R China. CALTECH, Jet Prop Lab, Pasadena, CA USA. Univ Texas, Ctr Space Res, Austin, TX USA. RP Zhang, FP (reprint author), Chinese Acad Sci, United Ctr Astrogeodynam Res, Natl Astron Observ, Shanghai Astron Observ, Shanghai 200030, Peoples R China. NR 19 TC 7 Z9 9 U1 2 U2 8 PU SCIENCE CHINA PRESS PI BEIJING PA 16 DONGHUANGCHENGGEN NORTH ST, BEIJING 100717, PEOPLES R CHINA SN 1001-6538 J9 CHINESE SCI BULL JI Chin. Sci. Bull. PD NOV PY 2002 VL 47 IS 21 BP 1772 EP + DI 10.1360/02tb9387 PG 10 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 606VC UT WOS:000178754200003 ER PT J AU Barragan, M Woods, S Julien, HL Wilson, DB Saulsberry, R AF Barragan, M Woods, S Julien, HL Wilson, DB Saulsberry, R TI Thermodynamic equations of state for hydrazine and monomethylhydrazine SO COMBUSTION AND FLAME LA English DT Article AB Thermodynamic equations of state are evaluated for the aerospace fuels hydrazine and monomethylhydrazine using Peng-Robinson (PR) and Soave-Redlich-Kwong (SRK) formulations. The PR formulation is shown to be the best fit for hydrazine, and the SRK formulation to be the best fit for monomethylhydrazine, based on available critical property data and evaluations of thermodynamic consistency. The adequacy of the differing property data for these fuels in the literature is discussed, and the methodology used to validate the formulations is outlined. The importance of using appropriate real fluid equations of state in thermodynamic safety and hazards analysis of fuel systems is demonstrated by considering an adiabatic compression of gaseous fuels previously postulated in accident scenarios of aerospace propulsion systems. Calculation of isentropic compression temperatures for pure components using ideal gas constant heat capacity, ideal gas with variable heat capacity, and real fluid equations of state are compared to illustrate the need for real fluid equations of state. In addition, three separate approaches are used for estimating isentropic compression temperatures for mixtures involving these fuels, again illustrating the importance of treating these mixtures as real fluids for design and safety analysis. (C) 2002 by The Combustion Institute. C1 NASA, Honeywell Technol Solut Inc, White Sands Test Facil, Las Cruces, NM USA. NASA, Lyndon B Johnson Space Ctr, White Sands Test Facil, Las Cruces, NM USA. RP Julien, HL (reprint author), NASA, Honeywell Technol Solut Inc, White Sands Test Facil, Las Cruces, NM USA. NR 20 TC 5 Z9 5 U1 2 U2 5 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0010-2180 J9 COMBUST FLAME JI Combust. Flame PD NOV PY 2002 VL 131 IS 3 BP 316 EP 328 AR PII S0010-2180(02)00410-8 DI 10.1016/S0010-2180(02)00410-8 PG 13 WC Thermodynamics; Energy & Fuels; Engineering, Multidisciplinary; Engineering, Chemical; Engineering, Mechanical SC Thermodynamics; Energy & Fuels; Engineering GA 618MD UT WOS:000179421100008 ER PT J AU Lathouwers, D Bellan, J AF Lathouwers, D Bellan, J TI A posteriori assessment of assumptions used in the modeling of dense reactive granular flows SO COMBUSTION AND FLAME LA English DT Article ID BIOMASS PYROLYSIS; FLUIDIZED-BEDS; MIXTURES C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Delft Univ Technol, IRI, NL-2600 AA Delft, Netherlands. RP Bellan, J (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 6 TC 2 Z9 2 U1 0 U2 1 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0010-2180 J9 COMBUST FLAME JI Combust. Flame PD NOV PY 2002 VL 131 IS 3 BP 353 EP 356 AR PII S0010-2180(02)00412-1 DI 10.1016/S0010-2180(02)00412-1 PG 4 WC Thermodynamics; Energy & Fuels; Engineering, Multidisciplinary; Engineering, Chemical; Engineering, Mechanical SC Thermodynamics; Energy & Fuels; Engineering GA 618MD UT WOS:000179421100011 ER PT J AU Hambaba, A McMasters, E AF Hambaba, A McMasters, E TI Process machine implementation using distributed objects SO COMPUTERS & ELECTRICAL ENGINEERING LA English DT Article AB Manufacturing environments are moving away from stable, high volume environments to more flexible and lean environments. Industries' objectives included improvement of the manufacturing process and the creation of a next generation computer integrated manufacturing (CIM) system architecture that could exploit new manufacturing technologies. This paper documents the implementation of the machine control and factory management portions of the CIM framework using distributed objects technology and a common objects request broker architecture compliant object request broker. (C) 2002 Elsevier Science Ltd. All rights reserved. C1 San Jose State Univ, Coll Engn, CISE Dept, Mfg Informat Sys Engn MISE Lab, San Jose, CA 95192 USA. NASA, Ames Res Ctr, Natl Res Council, Moffett Field, CA 94035 USA. RP Hambaba, A (reprint author), San Jose State Univ, Coll Engn, CISE Dept, Mfg Informat Sys Engn MISE Lab, San Jose, CA 95192 USA. NR 9 TC 0 Z9 0 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0045-7906 J9 COMPUT ELECTR ENG JI Comput. Electr. Eng. PD NOV PY 2002 VL 28 IS 6 BP 481 EP 500 AR PII S0045-7906(00)00067-7 DI 10.1016/S0045-7906(00)00067-7 PG 20 WC Computer Science, Hardware & Architecture; Computer Science, Interdisciplinary Applications; Engineering, Electrical & Electronic SC Computer Science; Engineering GA 584JE UT WOS:000177462800004 ER PT J AU Gilbes, F Muller-Karger, FE Del Castillo, CE AF Gilbes, F Muller-Karger, FE Del Castillo, CE TI New evidence for the West Florida Shelf plume SO CONTINENTAL SHELF RESEARCH LA English DT Article DE Phytoplankton; algal blooms; shelf dynamics; plumes; river discharge; ocean color; Gulf of Mexico; West Florida Shelf ID PERFORMANCE LIQUID-CHROMATOGRAPHY; SPRING PHYTOPLANKTON BLOOM; RED-TIDE DINOFLAGELLATE; CHLOROPHYLL-A; PHOTOSYNTHETIC PIGMENTS; TOTAL PHOSPHORUS; OCEAN; PHEOPIGMENTS; MEXICO; GULF AB The occurrence of an episodic chlorophyll plume detected on the West Florida Shelf between 1979 and 1986 was confirmed in March 1995 with shipboard data and in March 1998 with new ocean color data from the SeaWiFS sensor. New evidence is presented to support the hypothesis that diatom blooms off Apalachicola Bay are the precursor of the seasonal West Florida Shelf plume, and that the nutrient requirements for such blooms, especially silicate, can be supported by river discharge. The observations indicate that the impact of rivers is maximal over the middle shelf and decreases over the outer shelf. Salinity and discharge measurements support the concept that the Apalachicola River had a major impact at distances exceeding 100 km from the coast and that it plays an important role in the formation of offshore blooms. Preliminary analyses suggest that successional processes lead to cryptophytes dominating in the offshore blooms. (C) 2002 Elsevier Science Ltd. All rights reserved. C1 Univ Puerto Rico, Dept Geol, Mayaguez, PR 00681 USA. Univ S Florida, Coll Marine Sci, St Petersburg, FL 33701 USA. NASA, Stennis Space Ctr, MS USA. RP Gilbes, F (reprint author), Univ Puerto Rico, Dept Geol, POB 9017, Mayaguez, PR 00681 USA. RI Del Castillo, Carlos/N-2601-2013 NR 43 TC 23 Z9 23 U1 0 U2 6 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 NOV PY 2002 VL 22 IS 17 BP 2479 EP 2496 AR PII S0278-4343(02)00102-4 DI 10.1016/S0278-4343(02)00102-4 PG 18 WC Oceanography SC Oceanography GA 620PD UT WOS:000179541000003 ER PT J AU Pusey, ML Nadarajah, A AF Pusey, ML Nadarajah, A TI A model for tetragonal lysozyme crystal nucleation and growth SO CRYSTAL GROWTH & DESIGN LA English DT Article; Proceedings Paper CT 223rd National Meeting of the American-Chemical-Society CY APR 07-11, 2002 CL ORLANDO, FLORIDA SP Amer Chem Soc ID ANGLE NEUTRON-SCATTERING; EGG-WHITE LYSOZYME; ATOMIC-FORCE MICROSCOPY; PROTEIN CRYSTAL; SELF-ASSOCIATION; SEDIMENTATION EQUILIBRIUM; MACROMOLECULAR SOLUTIONS; GLOBULAR-PROTEINS; PHASE-TRANSITION; 101 FACES AB Macromolecular crystallization is a complex process, involving a system that typically has five or more components (macromolecule; water, buffer + counterion, and precipitant). Whereas small molecules have only a few contacts in the crystal lattice, macromolecules generally have 10's or even 100's of contacts between molecules. Formation of a consistent, ordered, three-dimensional (3D) structure may be difficult or impossible in the absence of any or presence of too many strong interactions. Further complicating the process is the inherent structural asymmetry of monomeric (single chain) macromolecules. The process of crystal nucleation and growth involves the ordered assembly of growth units into a defined 3D lattice. We propose that tetragonal lysozyme crystal nucleation and growth solutions are highly self-associated and that associated species having 43 helix symmetry are the building blocks for the nucleation process. This solution phase self-association carries over into the crystal growth phase, with the aggregated species as the growth units, recapitulating the nucleation process. The symmetry acquired in solution phase self-association facilitates both nucleation and crystal growth. If this model is correct, then fluids and crystal growth models assuming a strictly monodisperse nutrient solution need to be revised. This model has been developed from experimental evidence based upon face growth rate, atomic force microscopy, and fluorescence energy transfer data for the nucleation and growth of tetragonal lysozyme crystals. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. Univ Toledo, Dept Chem Engn, Toledo, OH 43606 USA. RP Pusey, ML (reprint author), NASA, George C Marshall Space Flight Ctr, Biophys SD46, Huntsville, AL 35812 USA. NR 79 TC 20 Z9 21 U1 1 U2 16 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1528-7483 J9 CRYST GROWTH DES JI Cryst. Growth Des. PD NOV-DEC PY 2002 VL 2 IS 6 BP 475 EP 483 DI 10.1021/cg0200107 PG 9 WC Chemistry, Multidisciplinary; Crystallography; Materials Science, Multidisciplinary SC Chemistry; Crystallography; Materials Science GA 615AY UT WOS:000179224700002 ER PT J AU Abdul-Aziz, A AF Abdul-Aziz, A TI Assessment of crack growth in a space shuttle main engine first-stage high-pressure fuel turbopump blade SO FINITE ELEMENTS IN ANALYSIS AND DESIGN LA English DT Article AB A two-dimensional finite element fracture mechanics analysis of a space shuttle main engine (SSME) turbine blade firtree was performed using the MARC finite element code. The analysis was conducted under combined effects of thermal and mechanical loads at steady-state conditions. Data from a typical engine stand cycle of the SSME engine were used to run a heat transfer analysis and, subsequently, a thermal structural fracture mechanics analysis. Temperature and stress contours for the firtree under these operating conditions were generated. High stresses were found at the firtree lobes where crack initiation was triggered. A life assessment of the firtree was done by assuming an initial and a final crack size. (C) 2002 Elsevier Science B.V. All rights reserved. C1 Cleveland State Univ, NASA, Glenn Res Ctr, Dept Civil & Environm Engn, Cleveland, OH 44135 USA. RP Abdul-Aziz, A (reprint author), Cleveland State Univ, NASA, Glenn Res Ctr, Dept Civil & Environm Engn, 21000 Brook Pk Rd,MS 6-1, Cleveland, OH 44135 USA. NR 11 TC 3 Z9 4 U1 1 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-874X J9 FINITE ELEM ANAL DES JI Finite Elem. Anal. Des. PD NOV PY 2002 VL 39 IS 1 BP 1 EP 15 AR PII S0168-874X(02)00058-6 DI 10.1016/S0168-874X(02)00058-6 PG 15 WC Mathematics, Applied; Mechanics SC Mathematics; Mechanics GA 609VB UT WOS:000178924300001 ER PT J AU Hshieh, FY Hirsch, DB Williams, JH AF Hshieh, FY Hirsch, DB Williams, JH TI Short communication: Autoignition temperature of trichlorosilanes SO FIRE AND MATERIALS LA English DT Article AB Trichlorosilanes are important silicon intermediates used to manufacture silicone materials. Because they are produced and used in large quantities and some are very reactive, it is important to determine the autoignition temperature (AIT) of trichlorosilanes. This short communication reports the AIT of eight important trichlorosilanes and discusses the effect of substituted groups on the AIT. Copyright (C) 2002 John Wiley Sons, Ltd. C1 Honeywell Technol Solut Inc, Las Cruces, NM 88004 USA. NASA, Johnson Space Ctr, White Sands Test Facil, Las Cruces, NM 88004 USA. RP Hshieh, FY (reprint author), Honeywell Technol Solut Inc, POB 20, Las Cruces, NM 88004 USA. NR 6 TC 4 Z9 4 U1 0 U2 1 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX PO19 1UD, ENGLAND SN 0308-0501 J9 FIRE MATER JI Fire Mater. PD NOV-DEC PY 2002 VL 26 IS 6 BP 289 EP 290 DI 10.1002/fam.804 PG 2 WC Materials Science, Multidisciplinary SC Materials Science GA 642TU UT WOS:000180821400005 ER PT J AU Chen, JH Papanastassiou, DA Wasserburg, GJ AF Chen, JH Papanastassiou, DA Wasserburg, GJ TI Re-Os and Pd-Ag systematics in Group IIIAB irons and in pallasites SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Article ID EARLY SOLAR-SYSTEM; TRACE-ELEMENT FRACTIONATION; ISOTOPE SYSTEMATICS; CHEMICAL FRACTIONATIONS; MASS-SPECTROMETRY; CORE FORMATION; GROUP-IIAB; METEORITES; OSMIUM; RHENIUM AB Using improved analytical techniques, which reduce the Re blanks by factors of 8 to 10, we report new Re-Os data on low Re and low PGE pallasites (PAL-anom) and IIIAB irons. The new pallasite samples nearly double the observed range in Re/Os for pallasites and allow the determination of an isochron of slope 0.0775+/-0.0008 (T=4.50+/-0.04 Ga, using the adjusted lambda(187)Re=1.66x10(-11) a(-1)) and initial (Os-187/Os-188)(0)=0.09599+/-0.00046. If the data on different groups of pallasites (including the "anomalous" pallasites) are considered to define a whole-rock isochron, their formation would appear to be distinctly younger than for the iron meteorites by similar to60 Ma. Five IIIAB irons (Acuna, Bella Roca, Chupaderos, Grant, and Bear Creek), with Re contents ranging from 0.9 to 2.8 ppb, show limited Re/Os fractionation and plot within errors on the IIAB iron meteorite isochron of slope 0.07848+/-0.00018 (T=4.56+/-0.01 Ga) and initial (Os-187/Os-188)(0)=0.09563+/-0.00011. Many of the meteorites were analyzed also for Pd-Ag and show Ag-107 enrichments correlated with Pd/Ag, requiring early formation and fractionation of the FeNi metal, in a narrow time interval, after injection of live Pd-107 (t(1/2)=6.5 Ma) into the solar nebula. Based on Pd-Ag, the, typical range in relative ages of these meteorites is less than or equal to10 Ma. The Pd-Ag results suggest early formation and preservation of the Pd-107-Ag-107 systematics, both for IIIAB irons and for pallasites, while the younger Re-Os apparent age for pallasites suggests that the Re-Os system in pallasites was subject to re-equilibration. The low Re and low PGE pallasites show significant Re/Os fractionation (higher Re/Os) as the Re and PGE contents decrease. By contrast, the IIIAB irons show a restricted range in Re/Os, even for samples with extremely low Re and PGE contents. There is a good correlation of Re and Ir contents. The correlation of Re and Os contents for IIIAB irons shows a similar complex pattern as observed for IIAB irons (Morgan et al., 1995), and neither can be ascribed to a continuous fractional crystallization process with uniform solid-metal/liquid-metal distribution coefficients. Copyright (C) 2002 Elsevier Science Ltd. C1 CALTECH, Div Geol & Planetary Sci, Lunat Asylum, Pasadena, CA 91125 USA. CALTECH, Jet Prop Lab, Div Earth & Space Sci, Pasadena, CA 91109 USA. RP Papanastassiou, DA (reprint author), CALTECH, Div Geol & Planetary Sci, Lunat Asylum, Mail Code 170-25, Pasadena, CA 91125 USA. NR 59 TC 19 Z9 23 U1 1 U2 7 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0016-7037 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD NOV PY 2002 VL 66 IS 21 BP 3793 EP 3810 AR PII S0016-7037(02)00952-3 DI 10.1016/S0016-7037(02)00952-3 PG 18 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 608ZT UT WOS:000178878700010 ER PT J AU Sessions, AL Jahnke, LL Schimmelmann, A Hayes, JM AF Sessions, AL Jahnke, LL Schimmelmann, A Hayes, JM TI Hydrogen isotope fractionation in lipids of the methane-oxidizing bacterium Methylococcus capsulatus SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Article ID FRESH-WATER ENVIRONMENTS; FATTY-ACID COMPOSITION; METHANOTROPHIC BACTERIA; ISOPRENOID BIOSYNTHESIS; ACETATE FERMENTATION; METHYL STEROL; D/H RATIOS; CARBON; BIOMARKERS; DEUTERIUM AB Hydrogen isotopic compositions of individual lipids from Methylococcus capsulatus, an aerobic, methane-oxidizing bacterium, were analyzed by hydrogen isotope-ratio-monitoring gas chromatography-mass spectrometry (GC-MS). The purposes of the study were to measure isotopic fractionation factors between methane, water, and lipids and to examine the biochemical processes that determine the hydrogen isotopic composition of lipids. M. capsulatus was grown in six replicate cultures in which the deltaD values of methane and water were varied independently. Measurement of concomitant changes in deltaD values of lipids allowed estimation of the proportion of hydrogen derived from each source and the isotopic fractionation associated with the utilization of each source. All lipids examined, including fatty acids, sterols, and hopanols, derived 31.4 +/- 1.7% of their hydrogen from methane. This was apparently true whether the cultures were harvested during exponential or stationary phase. Examination of the relevant biochemical pathways indicates that no hydrogen is transferred directly (with C-H bonds intact) from methane to lipids. Accordingly, we hypothesize that all methane H is oxidized to H2O, which then serves as the H source for all biosynthesis, and that a balance between diffusion of oxygen and water across cell membranes controls the concentration of methane-derived H2O at 31%. Values for alpha(l/w), the isotopic fractionation between lipids and water, were 0.95 for fatty acids and 0.85 for isoprenoid lipids. These fractionations are significantly smaller than those measured in higher plants and algae. Values for alpha(l/m), the isotopic fractionation between lipids and methane, were 0.94 for fatty acids and 0.79 for isoprenoid lipids. Based on these results, we predict that methanotrophs living in seawater and consuming methane with typical deltaD values will produce fatty acids with deltaD between -50 and -170parts per thousand, and sterols and hopanols with deltaD between - 150 and -270parts per thousand, Copyright (C) 2002 Elsevier Science Ltd. C1 Woods Hole Oceanog Inst, Dept Geol & Geophys, Woods Hole, MA 02543 USA. NASA, Ames Res Ctr, Exobiol Branch, Moffett Field, CA 94035 USA. Indiana Univ, Dept Geol Sci, Biogeochem Labs, Bloomington, IN 47405 USA. RP Sessions, AL (reprint author), Woods Hole Oceanog Inst, Dept Geol & Geophys, Woods Hole, MA 02543 USA. RI Sessions, Alex/C-2752-2008 OI Sessions, Alex/0000-0001-6120-2763 NR 53 TC 57 Z9 57 U1 6 U2 24 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0016-7037 J9 GEOCHIM COSMOCHIM AC JI Geochim. Cosmochim. Acta PD NOV PY 2002 VL 66 IS 22 BP 3955 EP 3969 AR PII S0016-7037(02)00981-X DI 10.1016/S0016-7037(02)00981-X PG 15 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 615AH UT WOS:000179223300008 ER PT J AU Melbourne, TI Webb, FH AF Melbourne, TI Webb, FH TI Precursory transient slip during the 2001 M-w=8.4 Peru earthquake sequence from continuous GPS SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID EVENT; JAPAN AB Two-hour position estimates from a continuous GPS station located at Arequipa, Peru, document precursory deformation beginning 18 hours prior to an M-w=7.6 aftershock of the June 23rd 2001 M-w=8.4 earthquake. This preseismic signal appears on the north and east components as a slow displacement with an amplitude twice that of the subsequent coseismic. Analysis of three years of 18-hour rate measurement shows this signal to be unprecedented and beyond four standard deviations from the mean rate. The best fitting centroid is directionally consistent with slow slip along the plate interface and suggests the preseismic deformation arises from creep near the aftershock rupture. This implies the Nazca-South American plate interface slipped slowly prior to seismogenic faulting. These observations indicate the M-w=7.6 earthquake grew out of slow slip along the plate interface and clearly demonstrate the breadth of slip rates accommodated by subduction zone plate interfaces. C1 Cent Washington Univ, Dept Geol Sci, Ellensburg, WA 98926 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Melbourne, TI (reprint author), Cent Washington Univ, Dept Geol Sci, Ellensburg, WA 98926 USA. NR 18 TC 29 Z9 29 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD NOV 1 PY 2002 VL 29 IS 21 AR 2032 DI 10.1029/2002GL015533 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 639DG UT WOS:000180611900028 ER PT J AU Yan, XH Zhou, YH Pan, JY Zheng, DW Fang, MQ Liao, XH He, MX Liu, WT Ding, XL AF Yan, XH Zhou, YH Pan, JY Zheng, DW Fang, MQ Liao, XH He, MX Liu, WT Ding, XL TI Pacific warm pool excitation, earth rotation and El Nino southern oscillations SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID ATMOSPHERIC ANGULAR-MOMENTUM; OF-DAY VARIATION; VARIABILITIES; MOTION; EVENTS AB The interannual changes in the Earth's rotation rate, and hence in the length of day (LOD), are thought to be caused by the variation of the atmospheric angular momentum (AAM). However, there is still a considerable portion of the LOD variations that remain unexplained. Through analyzing the non-atmospheric LOD excitation contributed by the Western Pacific Warm Pool (WPWP) during the period of 1970-2000, the positive effects of the WPWP on the interannual LOD variation are found, although the scale of the warm pool is much smaller than that of the solid Earth. These effects are specifically intensified by the El Nino events, since more components of the LOD-AAM were accounted for by the warm pool excitation in the strong El Nino years. Changes in the Earth's rotation rate has attracted significant attention, not only because it is an important geodetic issue but also because it has significant value as a global measure of variations within the hydrosphere, atmosphere, cryosphere and solid Earth, and hence the global changes. C1 Univ Delaware, Grad Coll Marine Studies, Newark, DE 19716 USA. Chinese Acad Sci, Shanghai Astron Observ, Shanghai, Peoples R China. Ocean Univ Qingdao, Ocean Remote Sensing Inst, Qingdao 266003, Peoples R China. CALTECH, Jet Prop Lab, Pasadena, CA USA. Hong Kong Polytech Univ, Dept Land Surveying & Geoinformat, Hong Kong, Hong Kong, Peoples R China. Chinese Acad Sci, United Ctr Astrogeodynam Res, Shanghai, Peoples R China. RP Yan, XH (reprint author), Univ Delaware, Grad Coll Marine Studies, Newark, DE 19716 USA. RI Ding, Xiaoli/K-4596-2013 OI Ding, Xiaoli/0000-0002-5733-3629 NR 25 TC 6 Z9 6 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD NOV 1 PY 2002 VL 29 IS 21 AR 2031 DI 10.1029/2002GL015685 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 639DG UT WOS:000180611900027 ER PT J AU Romon-Martin, J Barucci, MA de Bergh, C Doressoundiram, A Peixinho, N Poulet, F AF Romon-Martin, J Barucci, MA de Bergh, C Doressoundiram, A Peixinho, N Poulet, F TI Observations of Centaur 8405 Asbolus: Searching for water ice SO ICARUS LA English DT Article DE centaurs; spectroscopy; spectrophotometry; surfaces, asteroids; infrared observations ID CENTAUR 8405 ASBOLUS; OPTICAL-CONSTANTS; INFRARED-SPECTROSCOPY; SURFACE; PHOTOMETRY; OBJECTS; GRAINS; SATELLITE; THOLINS; MODEL AB Near-infrared spectra of Centaur 8405 Asbolus have been obtained, covering the whole rotational period. Complementary photometry and visible spectroscopy have also been performed. The aim of this project was to confirm or refute the water ice detection on one side of Asbolus reported by Kern et al. (2000 Astrophys. J. 542, L155-LI59). We found no absorption feature at any rotational phase of Asbolus. Our study is the first in-depth investigation of a centaur over a complete rotational period. Our results seem also to indicate that a change in the slope from 0.8 to 1.0 mum may occur in Asbolus spectrum. (C) 2002 Elsevier Science (USA). C1 Observ Paris, LESIA, F-92195 Meudon, France. Astron Observ, CAAUL, Lisbon, Portugal. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Romon-Martin, J (reprint author), Observ Paris, LESIA, F-92195 Meudon, France. EM jennifer.romon@obspm.fr RI Peixinho, Nuno/B-2570-2014 OI Peixinho, Nuno/0000-0002-6830-476X NR 26 TC 17 Z9 17 U1 1 U2 1 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD NOV PY 2002 VL 160 IS 1 BP 59 EP 65 DI 10.1006/icar.2002.6959 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 617MF UT WOS:000179364900007 ER PT J AU Glandorf, DL Colaprete, A Tolbert, MA Toon, OB AF Glandorf, DL Colaprete, A Tolbert, MA Toon, OB TI CO2 snow on Mars and early Earth: Experimental constraints SO ICARUS LA English DT Article DE Mars, atmosphere; ices; experimental techniques ID CARBON-DIOXIDE CLOUDS; ICE CLOUDS; OPTICAL-CONSTANTS; CLIMATE; CONDENSATION; ATMOSPHERE; H2O AB Greenhouse warming due to carbon dioxide atmospheres may be responsible for maintaining the early Earth's surface temperature above freezing and may even have allowed for liquid water on early Mars. However, the high levels Of CO2 required for such warming should have also resulted in the formation Of CO2 clouds. These clouds, depending on their particle size, could lead to either warming or cooling. The particle size in turn,is determined by the nucleation and growth conditions. Here we present laboratory studies of the nucleation and growth of carbon dioxide on water ice under martian atmospheric conditions. We find that a critical saturation, S = 1.34, is required for nucleation, corresponding to a contact parameter between solid water and solid carbon dioxide of m = 0.95. We also find that after nucleation occurs, growth Of CO2 is very rapid, and we report the growth rates at a number of supersaturations. Because growth would be expected to continue until the CO2 pressure is lowered to its vapor pressure, we expect particles larger than those being currently suggested for the present and past martian atmospheres. Using this information in a microphysical model described in a companion paper, we find that CO2 clouds are best described as "snow," having a relatively small number of large particles. (C) 2002 Elsevier Science (USA). C1 Univ Colorado, Dept Chem & Biochem, Boulder, CO 80309 USA. Univ Colorado, CIRES, Boulder, CO 80309 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ Colorado, Atmospher & Space Phys Lab, Boulder, CO 80309 USA. Univ Colorado, Dept Atmospher & Ocean Sci, Boulder, CO 80309 USA. RP Glandorf, DL (reprint author), Univ Colorado, Dept Chem & Biochem, Campus Box 216, Boulder, CO 80309 USA. NR 25 TC 33 Z9 33 U1 0 U2 10 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD NOV PY 2002 VL 160 IS 1 BP 66 EP 72 DI 10.1006/icar.2002.6953 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 617MF UT WOS:000179364900008 ER PT J AU Alvarellos, JL Zahnle, KJ Dobrovolskis, AR Hamill, P AF Alvarellos, JL Zahnle, KJ Dobrovolskis, AR Hamill, P TI Orbital evolution of impact ejecta from Ganymede SO ICARUS LA English DT Article DE cratering; Ganymede; satellites of Jupiter; orbits ID RESTRICTED 3-BODY PROBLEM; SATURN SYSTEM; SOLAR-SYSTEM; SATELLITE; DISRUPTION; HYPERION; BEHAVIOR; ORIGIN; COMETS; EARTH AB We have numerically computed the orbital evolution of similar to10(3) particles representing high-speed ejecta from Gilgamesh, the largest impact basin on Ganymede. The integration includes the four Galilean satellites, Jupiter (including J(2) and J(4)), Saturn, and the Sun. The integrations last 100,000 years. The particles are ejected at a variety of speeds and directions, with the fastest particles ejected at 1.4 times the escape speed v(esc) equivalent to root2GM(G)/R-G of Ganymede. Ejecta with speeds v < 0.96v(esc) follow suborbital trajectories. At v similar to 0.96v(esc) there is a transition characterized by complex behavior suggestive of chaos. For v > 0.96v(esc), most particles escape Ganymede and achieve orbits about Jupiter. Eventually most (similar to71%) of the jovicentric particles hit Ganymede, with 92% of these hitting within 1000 years. The accretion rate scales as I It. Their impact sites are randomly distributed, as expected for planetocentric debris. We estimate that most of the resulting impact craters are a few kilometers across and smaller. The rest of the escaping ejecta are partitioned as follows: similar to3% hit Io; similar to10% hit Europa; similar to13% hit Callisto; 2% reach heliocentric space; and less than similar to1% hit Jupiter. Only two particles survived the entire 10(5)-year integration. Ejecta from large impact events do not appear to be a plausible source of large craters on the Galilean satellites; however, such ejecta may account for the majority of small craters. (C) 2002 Elsevier Science (USA). C1 Loral, Space Syst, Palo Alto, CA 94303 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ Calif Santa Cruz, Univ Calif Observ, Lick Observ, Santa Cruz, CA 95064 USA. San Jose State Univ, Dept Phys, San Jose, CA 95192 USA. RP Alvarellos, JL (reprint author), Loral, Space Syst, 3825 Fabian Way,MS L-27, Palo Alto, CA 94303 USA. NR 38 TC 15 Z9 15 U1 0 U2 1 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD NOV PY 2002 VL 160 IS 1 BP 108 EP 123 DI 10.1006/icar.2002.6950 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 617MF UT WOS:000179364900012 ER PT J AU Marchis, F de Pater, I Davies, AG Roe, HG Fusco, T Le Mignant, D Descamps, P Macintosh, BA Prange, R AF Marchis, F de Pater, I Davies, AG Roe, HG Fusco, T Le Mignant, D Descamps, P Macintosh, BA Prange, R TI High-resolution Keck adaptive optics imaging of violent volcanic activity on Io SO ICARUS LA English DT Article DE Io; volcanism; infrared observations ID SILICATE VOLCANISM; THERMAL EMISSION; II-TELESCOPE; GALILEO; IMAGES; TEMPERATURE; NIMS; DECONVOLUTION; DISCOVERY; SSI AB Io, the innermost Galilean satellite of Jupiter, is a fascinating world. Data taken by Voyager and Galileo instruments have established that it is by far the most volcanic body in the Solar System and suggest that the nature of this volcanism could radically differ from volcanism. on Earth. We report on near-IR observations taken in February 2001 from the Earth-based 10-m W M. Keck 11 telescope using its adaptive optics system. After application of an appropriate deconvolution technique (MISTRAL), the resolution, similar to100 km on Io's disk, compares well with the best Galileo/NIMS resolution for global imaging and allows us for the first time to investigate the very nature of individual eruptions. On 19 February, we detected two volcanoes, Amirani and Tvashtar, with temperatures differing from the Galileo observations. On 20 February, we noticed a slight brightening near the Surt volcano. Two days later it had turned into an extremely bright volcanic outburst. The hot spot temperatures (> 1400 K) are consistent with a basaltic eruption and, being lower limits, do not exclude an ultramafic eruption. These outburst data have been fitted with a silicate-cooling model, which indicates that this is a highly vigorous eruption with a highly dynamic emplacement mechanism, akin to fire-fountaining. Its integrated thermal output was close to the total estimated output of Io, making this the largest ionian thermal outburst yet witnessed. (C) 2002 Elsevier Science (USA). C1 Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA. Univ Paris 11, Inst Astrophys Spatiale, F-91405 Orsay, France. Lawrence Livermore Natl Lab, Livermore, CA 94551 USA. Observ Paris, UMR CNRS 8028, Inst Mecan Celeste & Calcul Ephemerides, F-75014 Paris, France. WM Keck Observ, Kamuela, HI 96743 USA. Off Natl Etud & Rech Aerosp, DOTAE, F-92322 Chatillon, France. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Marchis, F (reprint author), Univ Calif Berkeley, Dept Astron, 601 Campbell Hall, Berkeley, CA 94720 USA. RI Marchis, Franck/H-3971-2012 NR 35 TC 47 Z9 47 U1 0 U2 2 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD NOV PY 2002 VL 160 IS 1 BP 124 EP 131 DI 10.1006/icar.2002.6955 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 617MF UT WOS:000179364900013 ER PT J AU Barbara, JM Esposito, LW AF Barbara, JM Esposito, LW TI Moonlet collisions and the effects of tidally modified accretion in Saturn's F ring SO ICARUS LA English DT Article DE planetary rings, Saturn; Saturn ID PLANETARY SATELLITES; GENERAL FORMULATION; DISRUPTION; MODEL; ASTEROIDS; EJECTA; SYSTEM; AUGUST AB We both test and offer an alternative to a meteoroid bombardment model (M. R. Showalter 1998, Science 282, 1099-1102) and suggest that anomalous localized brightenings in the F ring observed by Voyager result from disruptive collisions involving poorly consolidated moordets, or "rubble piles." This model can also explain the transient events observed during ring plane crossing. We have developed an evolutionary model that considers both the competing effects of accretion and disruption at the location of the F ring. Our numerical model is a Markov process where probabilities of mass transfer between the states of the system form a "transition matrix." Successive multiplications of this matrix by the state vector generate expectation values of the distribution after each time step as the system approaches quasi-equilibrium. Competing effects of accretion and disruption in the F ring are found to lead to a bimodal distribution of ring particle sizes. In fact, our simulation predicts the presence of a belt of kilometer-sized moonlets in the F ring. These moonlets may continually disrupt one another and re-accrete on short time scales. We also agree with J. N. Cuzzi and J. A. Burns (1988, Icarus 74,284-324), who suggest that the classical F ring itself may be the consequence of a relatively recent collision between two of the largest of these yet unseen objects. Cassini observations can confirm the existence of the moonlet belt by directly observing these objects or the waves they create in the rings. (C) 2002 Elsevier Science (USA). C1 Univ Colorado, Atmospher & Space Phys Lab, Boulder, CO 80309 USA. RP Barbara, JM (reprint author), NASA, Goddard Inst Space Studies, 2880 Broadway, New York, NY 10025 USA. NR 30 TC 42 Z9 42 U1 0 U2 1 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD NOV PY 2002 VL 160 IS 1 BP 161 EP 171 DI 10.1006/icar.2002.6962 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 617MF UT WOS:000179364900015 ER PT J AU Khare, BN Bakes, ELO Imanaka, H McKay, CP Cruikshank, DP Arakawa, ET AF Khare, BN Bakes, ELO Imanaka, H McKay, CP Cruikshank, DP Arakawa, ET TI Analysis of the time-dependent chemical evolution of Titan haze tholin SO ICARUS LA English DT Article DE Titan; tholins; stratospheric chemistry; aromatics; amines; alkanes; hydrocarbons; aerosols ID POLYCYCLIC AROMATIC-HYDROCARBONS; OPTICAL-PROPERTIES; INFRARED OBSERVATIONS; VERTICAL-DISTRIBUTION; ATMOSPHERE; AEROSOLS; EMISSION; SYSTEM AB Haze particles exert a significant influence over the thermodynamics and radiation absorption properties of the Titan haze, as well as its complex organic chemistry. Characterization of both the molecular and the submicrometer components of the haze is therefore vital for understanding the global properties of Titan. We have carried out a Titan tholin synthesis experiment and measured the time variation of the infrared spectrum of the product as a thin film developed. Also, to examine the possibility of oxygen contamination, we compared the infrared spectrum of the tholin film with that of a tholin film exposed to dry air and laboratory air. The objective of this study is to understand the chemical processes related to how simple organic molecules are processed into more complex haze particles. The progressive development of features characteristic of amines, aromatic and aliphatic hydrocarbons, and nitriles in the experimental mixture is clear. Of particular interest is the formation of aromatic rings after only a few seconds of glow discharge, indicating that these compounds appear to be intermediates between simple haze molecules and microphysical aerosols. The early dominance of aromatic ring structures is accompanied during the later stages of the experiment by the appearance of nitrile and amine compounds. This time-dependent succession of chemical structures provides vital clues to the possible chemical formation pathways of Titan haze aerosols. (C) 2002 Elsevier Science (USA). C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NASA, Ames Res Ctr, SETI Inst, Moffett Field, CA 94035 USA. NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA. Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA. RP Khare, BN (reprint author), NASA, Ames Res Ctr, Mail Stop 239-11, Moffett Field, CA 94035 USA. RI Imanaka, Hiroshi/E-7816-2012 NR 33 TC 34 Z9 34 U1 0 U2 7 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD NOV PY 2002 VL 160 IS 1 BP 172 EP 182 DI 10.1006/icar.2002.6899 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 617MF UT WOS:000179364900016 ER PT J AU Kludze, AK AF Kludze, AK TI Applying automation to spacecraft mission operations SO IEEE AEROSPACE AND ELECTRONIC SYSTEMS MAGAZINE LA English DT Article AB This study was initially undertaken to understand how commonalities among the application of proven automation processes such as aircraft control, nuclear power generation, auto manufacturing, etc. could be applied to spacecraft operations at NASA. These industries applied automation to reduce human repetitive task and mitigate risk, rather than create complete "lights out" operations as was the goal at NASA. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Kludze, AK (reprint author), NASA, Langley Res Ctr, Bldg 1209,Room 130A,MS434, Hampton, VA 23681 USA. NR 5 TC 1 Z9 1 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 0885-8985 J9 IEEE AERO EL SYS MAG JI IEEE Aerosp. Electron. Syst. Mag. PD NOV PY 2002 VL 17 IS 11 BP 3 EP 6 DI 10.1109/MAES.2002.1047371 PG 4 WC Engineering, Aerospace; Engineering, Electrical & Electronic SC Engineering GA 617AP UT WOS:000179337200001 ER PT J AU Ilchenko, VS Savchenkov, AA Matsko, AB Maleki, L AF Ilchenko, VS Savchenkov, AA Matsko, AB Maleki, L TI Sub-MicroWatt photonic microwave receiver SO IEEE PHOTONICS TECHNOLOGY LETTERS LA English DT Article DE electrooptic modulation; microresonators; microstrip resonators; microwave detectors; nonlinear optics; Q factor AB We report efficient photonic reception of nanowatt microwave signals by their direct upconversion into optical domain using high-Q whispering gallery modes in a millimeter size toroidal cavity fabricated from LiNbO3. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Ilchenko, VS (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Matsko, Andrey/A-1272-2007 NR 8 TC 53 Z9 55 U1 0 U2 4 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 1041-1135 J9 IEEE PHOTONIC TECH L JI IEEE Photonics Technol. Lett. PD NOV PY 2002 VL 14 IS 11 BP 1602 EP 1604 DI 10.1109/LPT.2002.803916 PG 3 WC Engineering, Electrical & Electronic; Optics; Physics, Applied SC Engineering; Optics; Physics GA 608LE UT WOS:000178847200038 ER PT J AU DiDomenico, LD AF DiDomenico, LD TI A comparison of time versus frequency domain antenna patterns SO IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION LA English DT Article DE antennas; arrays; beam forming; sparse arrays; time-domain signals; ultra-wideband AB This paper compares the performance of antenna arrays that use sinusoidal and ultra-short pulse waveforms. There are two parts to the paper: first, a comparison of narrowband versus ultra-wideband linear arrays using an analytic approach and second, a series of computer simulations used to extend the analytic results and to show the, characteristics of nonstandard array configurations. Analysis shows that antennas using ultra-short waveforms have highly desirable pattern properties that do not appreciably degrade under conditions of high array sparsity, failed elements, or antenna element position errors. Patterns are given that show these properties directly. These results are of particular importance to the emerging technology of base-band or time-domain communications and remote sensing. It addresses the practical problem of designing extremely large aperture space-based arrays without populating those arrays densely with antenna elements and also reducing the traditional fabrication tolerances. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP DiDomenico, LD (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 15 TC 13 Z9 13 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 0018-926X J9 IEEE T ANTENN PROPAG JI IEEE Trans. Antennas Propag. PD NOV PY 2002 VL 50 IS 11 BP 1560 EP 1566 DI 10.1109/TAP.2002.803960 PG 7 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA 639MY UT WOS:000180634400008 ER PT J AU Simon, MK AF Simon, MK TI The Nuttall Q function - Its relation to the Marcum Q function and its application in digital communication performance evaluation SO IEEE TRANSACTIONS ON COMMUNICATIONS LA English DT Article DE Marcum Q function; Nuttall Q function AB The Nuttall Q function is introduced and, for the case where the sum of its two order indices is odd, a closed-form expression is derived for it in terms of the Marcum Q function and modified Bessel functions of the first kind. Alternatively, a finite-range integral expression is also given for it, which has the identical form to that of the generalized Marcum Q function. Finally, digital communication performance applications involving the Nuttall Q function are presented to justify the value of the results. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Simon, MK (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 5 TC 42 Z9 43 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 0090-6778 J9 IEEE T COMMUN JI IEEE Trans. Commun. PD NOV PY 2002 VL 50 IS 11 BP 1712 EP 1715 DI 10.1109/TCOMM.2002.805270 PG 4 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA 624EJ UT WOS:000179747100002 ER PT J AU Mahesh, A Spinhirne, JD Duda, DP Eloranta, EW AF Mahesh, A Spinhirne, JD Duda, DP Eloranta, EW TI Atmospheric multiple scattering effects on GLAS altimetry - part II: Analysis of expected errors in antarctic altitude measurements SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE altimetry; climate change in the polar region; cloud studies; laser ranging; multiple scattering ID GREENLAND ICE-SHEET; CLOUD PROPERTIES; LASER ALTIMETRY; SOUTH-POLE; PLATEAU AB The altimetry bias in the Geoscience Laser Altimeter System or other laser altimeters resulting from atmospheric multiple scattering is studied in relationship to current knowledge of cloud properties over the Antarctic Plateau. Estimates of seasonal and interannual changes in the bias are presented. Results show the bias in altitude from multiple scattering in clouds would be a significant error source without correction. The selective use of low-optical-depth clouds or cloud-free observations, as well as improved analysis of the return pulse such as by the Gaussian method used here, is necessary to minimize the surface altitude errors. The magnitude of the bias is affected by variations in cloud height, cloud effective particle size, and optical depth. Interannual variations in these properties as well as in cloud cover fraction could lead to significant year-to-year variations in the altitude bias. Although cloud-free observations reduce biases in surface elevation measurements from space, over Antarctica these may often include near-surface blowing snow, also a source of scattering-induced delay. With careful selection and analysis of data, laser altimetry specifications can be met. C1 NASA, Goddard Earth Sci & Technol Ctr, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Hampton Univ, Ctr Atmospher Sci, Hampton, VA 23681 USA. Univ Wisconsin, Ctr Space Sci & Engn, Madison, WI 53706 USA. RP Mahesh, A (reprint author), NASA, Goddard Earth Sci & Technol Ctr, Greenbelt, MD 20771 USA. NR 17 TC 11 Z9 12 U1 1 U2 8 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD NOV PY 2002 VL 40 IS 11 BP 2353 EP 2362 DI 10.1109/TGRS.2002.803849 PG 10 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 636ZJ UT WOS:000180486900002 ER PT J AU Tupin, F Houshmand, B Datcu, M AF Tupin, F Houshmand, B Datcu, M TI Road detection in dense urban areas using SAR imagery and the usefulness of multiple views SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE different orientation views; Markov random fields; road detection; SAR images ID EXTRACTION AB This paper deals with the automatic extraction of the road network in dense urban areas using a few-meters-resolution synthetic aperture radar (SAR) images. The first part presents the proposed method, which is an adaptation of previous work to the specific case of urban areas. The major modifications are 1) the clique potentials of the Markov random field that extracts the road network are adapted and 2) a multiscale framework is used. Results on shuttle mission and aerial SAR images with different resolutions are presented. The second part is dedicated to road extraction combining two SAR images taken with different flight directions (orthogonal and antiparallel passes), and the obtained improvement is analyzed. C1 Telecom Paris, Signal & Image Proc Dept, F-75634 Paris, France. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. IMF, DLR, D-82234 Wessling, Germany. RP Tupin, F (reprint author), Telecom Paris, Signal & Image Proc Dept, F-75634 Paris, France. RI DATCU, Mihai/G-1655-2016 NR 17 TC 59 Z9 63 U1 1 U2 18 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD NOV PY 2002 VL 40 IS 11 BP 2405 EP 2414 DI 10.1109/TGRS.2002.803732 PG 10 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 636ZJ UT WOS:000180486900007 ER PT J AU Hamkins, J Zeger, K AF Hamkins, J Zeger, K TI Gaussian source coding with spherical codes SO IEEE TRANSACTIONS ON INFORMATION THEORY LA English DT Article; Proceedings Paper CT IEEE International Symposium on Information Theory CY JUN 24-29, 2001 CL WASHINGTON, DC SP IEEE DE data compression; Gaussian source; lattice coding; vector quantization ID LATTICE-VECTOR QUANTIZATION; MEMORYLESS SOURCES; LEECH LATTICE; ALGORITHM; BLOCK AB A fixed-rate shape-gain quantizer for the memoryless Gaussian source is proposed. The shape quantizer is constructed from wrapped spherical codes that map a sphere packing in Rk-1 onto a sphere in R-k, and the gain codebook is a globally optimal scalar quantizer. A wrapped Leech lattice shape quantizer is used to demonstrate a signal-to-quantization-noise ratio within 1 dB of the distortion-rate function for rates above 1 bit per sample, and an improvement over existing techniques of similar complexity. An asymptotic analysis of the tradeoff between gain quantization and shape quantization is also given. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Calif San Diego, Dept Elect & Comp Engn, La Jolla, CA 92093 USA. RP CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM hamkins@jpl.nasa.gov; zeger@ucsd.edu NR 47 TC 44 Z9 44 U1 0 U2 0 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 0018-9448 EI 1557-9654 J9 IEEE T INFORM THEORY JI IEEE Trans. Inf. Theory PD NOV PY 2002 VL 48 IS 11 BP 2980 EP 2989 DI 10.1109/TIT.2002.804056 PG 10 WC Computer Science, Information Systems; Engineering, Electrical & Electronic SC Computer Science; Engineering GA 606CU UT WOS:000178716300013 ER PT J AU Walker, JS Dold, P Croll, A Volz, MP Szofran, FR AF Walker, JS Dold, P Croll, A Volz, MP Szofran, FR TI Solutocapillary convection in the float-zone process with a strong magnetic field SO INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER LA English DT Article ID CYLINDRICAL LIQUID BRIDGES; 3-DIMENSIONAL NUMERICAL-SIMULATION; STATIC AXIAL FIELDS; THERMOCAPILLARY CONVECTION; CRYSTAL-GROWTH; INSTABILITIES; STABILITY; SILICON; SURFACE; FLOWS AB This paper treats the steady axisymmetric flow and mass transport in a cylindrical liquid bridge between the melting end of a feed rod and the solidifying end of an alloyed semiconductor crystal, There is a strong, uniform, steady, axial magnetic field. The surface tension depends on the temperature and the concentration of the species, while variations of the concentration occur because one species is rejected into the liquid during solidification. The thermocapillary and solutocapillary convections tend to cancel over part of the liquid bridge, For certain parameter ranges, there are two different stable solutions: one where the concentration gradient along the free surface leads to dominance by the solutocapillary convection and one where the mass transport due to the thermocapillary convection makes the concentration gradient along the free surface small, so that the thermocapillary convection is dominant. (C) 2002 Elsevier Science Ltd. All rights reserved. C1 Univ Illinois, Dept Mech & Ind Engn, Urbana, IL 61801 USA. Univ Freiburg, Inst Kristallog, D-79104 Freiburg, Germany. Tech Univ Freiberg, Inst NE Met & Reinststoffe, D-09599 Freiberg, Germany. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Walker, JS (reprint author), Univ Illinois, Dept Mech & Ind Engn, 1206 W Green St, Urbana, IL 61801 USA. RI Croell, Arne/A-2480-2013 OI Croell, Arne/0000-0002-8673-9994 NR 19 TC 7 Z9 8 U1 2 U2 5 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0017-9310 J9 INT J HEAT MASS TRAN JI Int. J. Heat Mass Transf. PD NOV PY 2002 VL 45 IS 23 BP 4695 EP 4702 AR PII S0017-9310(02)00159-X DI 10.1016/S0017-9310(02)00159-X PG 8 WC Thermodynamics; Engineering, Mechanical; Mechanics SC Thermodynamics; Engineering; Mechanics GA 592DY UT WOS:000177922500014 ER PT J AU Zatsepin, VI Adams, JH Ahn, HS Bashindzagyan, GL Batkov, KE Wang, JZ Wefel, JP Voronin, AG Wu, J Ganel, O Granger, D Gunasingha, R Guzik, TG Isbert, J Case, G Kim, HJ Kim, KC Kim, SK Christl, M Kouznetsov, EN Naqvi, SA Panasyuk, MI Panov, AD Price, B Samsonov, GA Sokolskaya, NV Seo, ES Sina, R Stewart, M Fazely, A Han, YJ Chang, J Schmidt, WKH AF Zatsepin, VI Adams, JH Ahn, HS Bashindzagyan, GL Batkov, KE Wang, JZ Wefel, JP Voronin, AG Wu, J Ganel, O Granger, D Gunasingha, R Guzik, TG Isbert, J Case, G Kim, HJ Kim, KC Kim, SK Christl, M Kouznetsov, EN Naqvi, SA Panasyuk, MI Panov, AD Price, B Samsonov, GA Sokolskaya, NV Seo, ES Sina, R Stewart, M Fazely, A Han, YJ Chang, J Schmidt, WKH TI Charge resolution in the ATIC experiment SO IZVESTIYA AKADEMII NAUK SERIYA FIZICHESKAYA LA Russian DT Article; Proceedings Paper CT 27th National Conference on Cosmic Rays CY AUG, 2001 CL HAMBURG, GERMANY C1 DV Skobeltsyn Nucl Phys Inst, Moscow, Russia. NASA, Ctr Space Res, Houston, TX USA. Univ Maryland, Baltimore, MD 21201 USA. Univ Louisiana, Lafayette, LA USA. Southern Univ, Baton Rouge, LA USA. Max Planck Inst, Lindau, Germany. Seoul Natl Univ, Seoul, South Korea. RP Zatsepin, VI (reprint author), DV Skobeltsyn Nucl Phys Inst, Moscow, Russia. RI Panasyuk, Mikhail/E-2005-2012; Zatsepin, Victor/J-2287-2012; Panov, Alexander/K-3952-2012 OI Panov, Alexander/0000-0003-2290-6498 NR 10 TC 0 Z9 0 U1 0 U2 2 PU MEZHDUNARODNAYA KNIGA PI MOSCOW PA 39 DIMITROVA UL., MOSCOW, 113095, RUSSIA SN 1026-3489 J9 IZV AKAD NAUK FIZ+ JI Izv. Akad. Nauk Ser. Fiz. PD NOV PY 2002 VL 66 IS 11 BP 1631 EP 1633 PG 5 WC Physics, Multidisciplinary SC Physics GA 633RR UT WOS:000180296700030 ER PT J AU van Dam, CP Shiu, HJ Banks, DW Tracy, RR Chase, J AF van Dam, CP Shiu, HJ Banks, DW Tracy, RR Chase, J TI In-flight visualization of supersonic flow transition using infrared imaging SO JOURNAL OF AIRCRAFT LA English DT Article ID BOUNDARY-LAYER STATE; HIGH-LIFT SYSTEM AB Infrared visualization was used to obtain information on the state of the boundary layer of a natural laminar flow airfoil in supersonic flight. In addition to the laminar/turbulent transition boundary, the infrared camera was able to detect shock waves and present a time-dependent view of the flow field. Thermal and flow mechanisms on the surface in flight were modeled numerically to aid in the design of the flight experiment and facilitate analysis of recorded infrared footage. A commercially available infrared camera was adapted for airborne use in this application. Readily available infrared technology has the capability to provide detailed visualization of various flow phenomena in subsonic to hypersonic flight regimes. C1 Univ Calif Davis, Dept Mech & Aeronaut Engn, Davis, CA 95616 USA. NASA, Dryden Flight Res Ctr, Aerodynam Branch, Edwards AFB, CA 93523 USA. Reno Aeronaut Corp, Carson City, NV 89702 USA. RP van Dam, CP (reprint author), Univ Calif Davis, Dept Mech & Aeronaut Engn, 1 Shields Ave, Davis, CA 95616 USA. NR 34 TC 2 Z9 2 U1 0 U2 4 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0021-8669 J9 J AIRCRAFT JI J. Aircr. PD NOV-DEC PY 2002 VL 39 IS 6 BP 936 EP 944 PG 9 WC Engineering, Aerospace SC Engineering GA 624LU UT WOS:000179761800003 ER PT J AU Wood, RM Bauer, SXS AF Wood, RM Bauer, SXS TI Discussion of knowledge-based design SO JOURNAL OF AIRCRAFT LA English DT Article AB A discussion of knowledge and knowledge-based design, as related to. the design of aircraft, is presented. A review of several knowledge-based design activities conducted at NASA Langley Research Center is provided, and a framework for a knowledge-based design capability is proposed and reviewed. The use of information technology to improve the efficiency and effectiveness of aerodynamic and multidisciplinary design, evaluation, and, analysis of aircraft through the coupling of these technologies and knowledge-based design is reviewed. The final section of the paper discusses future directions for design and the role of knowledge-based design. C1 NASA, Langley Res Ctr, Configurat Aerodynam Branch, Hampton, VA 23681 USA. RP Wood, RM (reprint author), NASA, Langley Res Ctr, Configurat Aerodynam Branch, Hampton, VA 23681 USA. NR 34 TC 3 Z9 3 U1 0 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0021-8669 J9 J AIRCRAFT JI J. Aircr. PD NOV-DEC PY 2002 VL 39 IS 6 BP 1053 EP 1060 DI 10.2514/2.3034 PG 8 WC Engineering, Aerospace SC Engineering GA 624LU UT WOS:000179761800017 ER PT J AU Chen, G Chapron, B Ezraty, R Vandemark, D AF Chen, G Chapron, B Ezraty, R Vandemark, D TI A global view of swell and wind sea climate in the ocean by satellite altimeter and scatterometer SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article ID WAVE HEIGHT; ERS-1; VARIABILITY; RETRIEVALS; SPECTRA; GROWTH; PERIOD; FETCH; SPEED; BUOYS AB Numerous case reports and regional studies on swell and wind sea events have been documented during the past century. The global picture of these common oceanic phenomena, however, is still incomplete in many aspects. This paper presents a feasibility study of using collocated wind speed and significant wave height measurements from simultaneous satellite scatterometer and altimeter sources to observe the spatial and seasonal pattern of dominant swell and wind wave zones in the world's oceans. Two energy- related normalized indices are proposed, on the basis of which global statistics of swell/ wind sea probabilities and intensities are obtained. It is found that three well- defined tongue- shaped zones of swell dominance, termed " swell pools, '' are located in the eastern tropical areas of the Pacific, the Atlantic, and the Indian Oceans, respectively. Regions of intensive wave growth are observed in the northwest Pacific, the northwest Atlantic, the Southern Ocean, and the Mediterranean Sea. Seasonality is distinct for the climate of both swell and wind sea, notably the large- scale northward bending of the swell pools in boreal summer, and the dramatic shift of wave- growing extent from a summer low to an autumn high. The results of this study may serve as a useful reference for a variety of activities, such as ocean wave modeling, satellite algorithm validation, coastal engineering, and ship routing, when information on swell and wind sea conditions is needed. C1 Ocean Univ Qingdao, Ocean Remote Sensing Inst, Qingdao 266003, Peoples R China. IFREMER, Dept Oceanog Spatiale, Ctr Brest, Plouzane, France. NASA, Goddard Space Flight Ctr, Wallops Flight Facil, Wallops Isl, VA 23337 USA. RP Chen, G (reprint author), Ocean Univ Qingdao, Ocean Remote Sensing Inst, 5 Yushan Rd, Qingdao 266003, Peoples R China. EM gechen@public.qd.sd.cn RI Chapron, Bertrand/O-6527-2015 NR 32 TC 74 Z9 90 U1 1 U2 11 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0739-0572 EI 1520-0426 J9 J ATMOS OCEAN TECH JI J. Atmos. Ocean. Technol. PD NOV PY 2002 VL 19 IS 11 BP 1849 EP 1859 DI 10.1175/1520-0426(2002)019<1849:AGVOSA>2.0.CO;2 PG 11 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA 610NY UT WOS:000178967900009 ER PT J AU Feynman, J Ruzmaikin, A Berdichevsky, V AF Feynman, J Ruzmaikin, A Berdichevsky, V TI The JPL proton fluence model: an update SO JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS LA English DT Article DE energetic protons; space environment; mission fluences solar energetic particles ID EVENTS; FLUXES AB The development of new technologies and the miniaturization of sensors bring new requirements for our ability to predict and forecast hazardous space weather conditions. Of particular importance are protons in the energy range from 10s to 100s of MeV which cause electronic part and solar cell degradation, and pose a hazard to biological systems in space and to personnel in polar orbit. Sporadic high-energy solar particle events are a main contributor to the fluences and fluxes of such protons. A statistical model, JPL 1991 (J. Geophys. Res. 98 (1991) 13,281), was developed to specify fluences for spacecraft design and is now widely used. Several major solar proton events have occurred since that model was developed and one objective of this paper is to see if changes need to be made in the model due to these recent events. Another objective is to review the methods used in JPL 1991 in the light of new understandings and to compare the JPL methods with those used in other models. We conclude that the method used in developing JPL 1991 model is valid and that the solar events occurring since then are completely consistent with the 1991 model. Since no changes are needed we suggest that the name of the model be changed to "the JPL fluence model". (C) 2002 Elsevier Science Ltd. All rights reserved. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Wayne State Univ, Dept Mech Engn, Detroit, MI 48202 USA. RP Feynman, J (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 23 TC 29 Z9 29 U1 0 U2 8 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1364-6826 J9 J ATMOS SOL-TERR PHY JI J. Atmos. Sol.-Terr. Phys. PD NOV PY 2002 VL 64 IS 16 BP 1679 EP 1686 AR PII S1364-6826(02)00118-9 DI 10.1016/S1364-6826(02)00118-9 PG 8 WC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences SC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences GA 601NR UT WOS:000178453100001 ER PT J AU Heirtzler, JR AF Heirtzler, JR TI The future of the South Atlantic anomaly and implications for radiation damage in space SO JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS LA English DT Article DE South Atlantic anomoly (SAA); radiation damage ID 1995 REVISION; MODELS; FIELD AB The South Atlantic anomaly (SAA) of the geomagnetic field plays a dominant role in the radiation damage occurring near Earth orbits. The historic and recent variations of the geomagnetic field in the South Atlantic are used to estimate the extent of the SAA until the year 2000. This projection indicates that radiation damage to spacecraft and humans in space will greatly increase and cover a much larger geographic area than present. Crown Copyright (C) 2002 Published by Elsevier Science Ltd. All rights reserved. C1 NASA, Goddard Space Flight Ctr, Lab Terrestrial Phys, Greenbelt, MD 20771 USA. RP Heirtzler, JR (reprint author), NASA, Goddard Space Flight Ctr, Lab Terrestrial Phys, Greenbelt, MD 20771 USA. NR 14 TC 46 Z9 50 U1 1 U2 8 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1364-6826 J9 J ATMOS SOL-TERR PHY JI J. Atmos. Sol.-Terr. Phys. PD NOV PY 2002 VL 64 IS 16 BP 1701 EP 1708 AR PII S1364-6826(02)00120-7 DI 10.1016/S1364-6826(02)00120-7 PG 8 WC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences SC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences GA 601NR UT WOS:000178453100003 ER PT J AU Miller, JR Russell, GL AF Miller, JR Russell, GL TI Projected impact of climate change on the energy budget of the Arctic Ocean by a global climate model SO JOURNAL OF CLIMATE LA English DT Article ID SEA-ICE; ANNUAL CYCLE; RIVER FLOW; SENSITIVITY; SIMULATIONS; THICKNESS; CLOUDS; FLUXES; CO2 AB The annual energy budget of the Arctic Ocean is characterized by a net heat loss at the air-sea interface that is balanced by oceanic heat transport into the Arctic. Two 150-yr simulations (1950-2099) of a global climate model are used to examine how this balance might change if atmospheric greenhouse gases (GHGs) increase. One is a control simulation for the present climate with constant 1950 atmospheric composition, and the other is a transient experiment with observed GHGs from 1950 to 1990 and 0.5% annual compounded increases of CO2 after 1990. For the present climate the model agrees well with observations of radiative fluxes at the top of the atmosphere, atmospheric advective energy transport into the Arctic, and surface air temperature. It also simulates the seasonal cycle and summer increase of cloud cover and the seasonal cycle of sea ice cover. In addition, the changes in high-latitude surface air temperature and sea ice cover in the GHG experiment are consistent with observed changes during the last 40 years. Relative to the control, the last 50-yr period of the GHG experiment indicates that even though the net annual incident solar radiation at the surface decreases by 4.6 W m(-2) (because of greater cloud cover and increased cloud optical depth), the absorbed solar radiation increases by 2.8 W m(-2) (because of less sea ice). Increased cloud cover and warmer air also cause increased downward thermal radiation at the surface so that the net radiation into the ocean increases by 5.0 W m(-2). The annual increase in radiation into the ocean, however, is compensated by larger increases in sensible and latent heat fluxes out of the ocean. Although the net energy loss from the ocean surface increases by 0.8 W m(-2), this is less than the interannual variability, and the increase may not indicate a long-term trend. The seasonal cycle of heat fluxes is significantly enhanced. The downward surface heat flux increases in summer (maximum of 19 W m(-2), or 23% in June) while the upward heat flux increases in winter (maximum of 16 W m(-2), or 28% in November). The increased downward flux in summer is due to a combination of increases in absorbed solar and thermal radiation and smaller losses of sensible and latent heat. The increased heat loss in winter is due to increased sensible and latent heat fluxes, which in turn are due to reduced sea ice cover. On the other hand, the seasonal cycle of surface air temperature is damped, as there is a large increase in winter temperature but little change in summer. The changes that occur in the various quantities exhibit spatial variability, with the changes being generally larger in coastal areas and at the ice margins. C1 Rutgers State Univ, Cook Coll, Dept Marine & Coastal Sci, New Brunswick, NJ 08901 USA. NASA Goddard, Inst Space Studies, New York, NY USA. RP Miller, JR (reprint author), Rutgers State Univ, Cook Coll, Dept Marine & Coastal Sci, 71 Dudley Rd, New Brunswick, NJ 08901 USA. NR 37 TC 9 Z9 9 U1 0 U2 2 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8755 J9 J CLIMATE JI J. Clim. PD NOV PY 2002 VL 15 IS 21 BP 3028 EP 3042 DI 10.1175/1520-0442(2002)015<3028:PIOCCO>2.0.CO;2 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 604DQ UT WOS:000178601100004 ER PT J AU Anyamba, A Tucker, CJ Mahoney, R AF Anyamba, A Tucker, CJ Mahoney, R TI From El Nino to La Nina: Vegetation response patterns over East and southern Africa during the 1997-2000 period SO JOURNAL OF CLIMATE LA English DT Article ID SEA-SURFACE TEMPERATURE; HIGH-RESOLUTION RADIOMETER; INDIAN-OCEAN; NOAA AVHRR; PRECIPITATION; OSCILLATION; RAINFALL; INDEX; VARIABILITY; DYNAMICS AB During the period 1997-2000, the global climate system experienced a transition from the strongest ENSO warm event this century in 1997/98 to a strong cold event in 1999/2000. Normalized difference vegetation index (NDVI) time series data derived from the Advanced Very High Resolution Radiometer (AVHRR) instrument aboard the NOAA polar-orbiting satellite series were analyzed to resolve the land surface response patterns over Africa during this period. The rearrangement of precipitation patterns induced by the change from El Nino to La Nina conditions had significant effects on biomass production in arid and semiarid lands of Africa as revealed by NDVI anomaly patterns, particularly in equatorial East Africa and southern Africa where the ENSO-precipitation linkage is most pronounced. In general, there was a reversal in NDVI response patterns in East (southern) Africa from positive (negative) during the El Nino in 1997/98 to negative (positive) during the La Nina event in 1999/2000. These changes can partially be attributed to east-west reversal in SST gradients in the Pacific Ocean basin but more significantly to the changes in the SST anomaly patterns in the equatorial western Indian Ocean (WIO) off the East African coast and the southern Indian Ocean off the southern African coast. C1 NASA, Goddard Space Flight Ctr, Biospher Sci Branch, Greenbelt, MD 20771 USA. Univ Maryland Baltimore Cty, Goddard Earth Sci Technol Ctr, Baltimore, MD 21228 USA. Global Sci & Technol, Greenbelt, MD USA. RP Anyamba, A (reprint author), NASA, Goddard Space Flight Ctr, Biospher Sci Branch, Code 923-0, Greenbelt, MD 20771 USA. NR 45 TC 79 Z9 80 U1 2 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 NOV PY 2002 VL 15 IS 21 BP 3096 EP 3103 DI 10.1175/1520-0442(2002)015<3096:FENOTL>2.0.CO;2 PG 8 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 604DQ UT WOS:000178601100009 ER PT J AU Loeb, NG Kato, S Wielicki, BA AF Loeb, NG Kato, S Wielicki, BA TI Defining top-of-the-atmosphere flux reference level for earth radiation budget studies SO JOURNAL OF CLIMATE LA English DT Article ID NIMBUS-7 ERB; SATELLITE; CLOUDS AB To estimate the earth's radiation budget at the top of the atmosphere (TOA) from satellite-measured radiances, it is necessary to account for the finite geometry of the earth and recognize that the earth is a solid body surrounded by a translucent atmosphere of finite thickness that attenuates solar radiation differently at different heights. As a result, in order to account for all of the reflected solar and emitted thermal radiation from the planet by direct integration of satellite-measured radiances, the measurement viewing geometry must be defined at a reference level well above the earth's surface (e. g., 100 km). This ensures that all radiation contributions, including radiation escaping the planet along slant paths above the earth's tangent point, are accounted for. By using a field-of-view (FOV) reference level that is too low (such as the surface reference level), TOA fluxes for most scene types are systematically underestimated by 1-2 W m(-2). In addition, since TOA flux represents a flow of radiant energy per unit area, and varies with distance from the earth according to the inverse-square law, a reference level is also needed to define satellite-based TOA fluxes. From theoretical radiative transfer calculations using a model that accounts for spherical geometry, the optimal reference level for defining TOA fluxes in radiation budget studies for the earth is estimated to be approximately 20 km. At this reference level, there is no need to explicitly account for horizontal transmission of solar radiation through the atmosphere in the earth radiation budget calculation. In this context, therefore, the 20-km reference level corresponds to the effective radiative "top of atmosphere'' for the planet. Although the optimal flux reference level depends slightly on scene type due to differences in effective transmission of solar radiation with cloud height, the difference in flux caused by neglecting the scene-type dependence is less than 0.1%. If an inappropriate TOA flux reference level is used to define satellite TOA fluxes, and horizontal transmission of solar radiation through the planet is not accounted for in the radiation budget equation, systematic errors in net flux of up to 8 W m 22 can result. Since climate models generally use a plane-parallel model approximation to estimate TOA fluxes and the earth radiation budget, they implicitly assume zero horizontal transmission of solar radiation in the radiation budget equation, and do not need to specify a flux reference level. By defining satellite-based TOA flux estimates at a 20-km flux reference level, comparisons with plane-parallel climate model calculations are simplified since there is no need to explicitly correct plane-parallel climate model fluxes for horizontal transmission of solar radiation through a finite earth. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. Hampton Univ, Ctr Atmospher Sci, Hampton, VA 23668 USA. RP Loeb, NG (reprint author), NASA, Langley Res Ctr, Mail Stop 420, Hampton, VA 23681 USA. NR 16 TC 21 Z9 21 U1 0 U2 2 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8755 J9 J CLIMATE JI J. Clim. PD NOV PY 2002 VL 15 IS 22 BP 3301 EP 3309 DI 10.1175/1520-0442(2002)015<3301:DTOTAF>2.0.CO;2 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 609CJ UT WOS:000178884800013 ER PT J AU Hu, FQ Atkins, HL AF Hu, FQ Atkins, HL TI Eigensolution analysis of the discontinuous Galerkin method with nonuniform grids I. One space dimension SO JOURNAL OF COMPUTATIONAL PHYSICS LA English DT Article DE finite element methods; unstructured grids; wave propagation; acoustics ID FINITE-ELEMENT METHODS; CONSERVATION-LAWS; WAVE-NUMBER; P-VERSION; EQUATIONS AB We present a detailed study of spatially propagating waves in a discontinuous Galerkin scheme applied to a system of linear hyperbolic equations. We start with an eigensolution analysis of the semidiscrete system in one space dimension with uniform grids. It is found that for any given order of the basis functions, there are at most two spatially propagating numerical wave modes for each physical wave of the partial differential equations (PDE). One of the modes can accurately represent the physical wave of the PDE and the other is spurious. The directions of propagation of these two numerical modes are opposite, and, in most practical cases, the spurious mode has a large damping rate. Furthermore, when an exact characteristics split flux formula is used, the spurious mode becomes nonexistent. For the physically accurate mode, it is shown analytically that the numerical dispersion relation is accurate to order 2p + 2, where p is the highest order of the basis polynomials. The results of eigensolution analysis are then utilized to study the effects of a grid discontinuity, caused by an abrupt change in grid size, on the numerical solutions at either side of the interface. It is shown that due to "mode decoupling," numerical reflections at grid discontinuity, when they occur, are always in the form of the spurious nonphysical mode. Closed-form numerical reflection and transmission coefficients are given and analyzed. Numerical examples that illustrate the analytical findings of the paper are also presented. (C) 2002 Elsevier Science (USA). C1 Old Dominion Univ, Dept Math & Stat, Norfolk, VA 23529 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Old Dominion Univ, Dept Math & Stat, Norfolk, VA 23529 USA. EM fang@math.odu.edu RI Hu, Fang/A-8206-2009 NR 23 TC 47 Z9 48 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 0021-9991 EI 1090-2716 J9 J COMPUT PHYS JI J. Comput. Phys. PD NOV 1 PY 2002 VL 182 IS 2 BP 516 EP 545 DI 10.1006/jcph.2002.7184 PG 30 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA 623AW UT WOS:000179681700007 ER PT J AU Coffey, MT Mankin, WG Hannigan, JW Toon, GC AF Coffey, MT Mankin, WG Hannigan, JW Toon, GC TI Airborne spectroscopic observations of chlorine activation and denitrification of the 1999/2000 winter Arctic stratosphere during SOLVE SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE SAGE III; polar; vortex; column; HCl; HNO3 ID OZONE DEPLETION AB [1] We have used Fourier transform spectrometers aboard the NASA DC-8 and on balloons as part of the SAGE III Ozone Loss and Validation Experiment (SOLVE) to record infrared absorption spectra of the polar stratosphere. From the high-resolution aircraft spectra we derived vertical column amounts of HCl, HF, NO2, HNO3, and a number of other gases for 11 flights in the region of the northern polar vortex. Vertical mixing ratio profiles are derived for a number of gases from two balloon flights. Within the vortex, where low values of total ozone are observed during the latter part of the observation period, we observed markedly reduced columns of HCl and NO2 and elevated columns of HF and HNO3 relative to columns outside the vortex. The low value for the ratio of HCl to HF indicates that HCl had been chemically or physically removed, probably providing a source for active chlorine. High values of HNO3 inside the vortex indicate that nitrogen oxides, which might otherwise mitigate chlorine-catalyzed ozone destruction, have been converted into more stable reservoirs. Because of incorporation into particles, some nitric acid may be removed from the stratosphere altogether. C1 Natl Ctr Atmospher Res, Div Atmospher Chem, Boulder, CO 80307 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Coffey, MT (reprint author), Natl Ctr Atmospher Res, Div Atmospher Chem, POB 3000, Boulder, CO 80307 USA. EM coffey@ncar.ucar.edu; mankin@ncar.ucar.edu; jamesw@ncar.ucar.edu; toon@mark4sun.jpl.nasa.gov NR 13 TC 0 Z9 0 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 NOV PY 2002 VL 108 IS D5 AR 8303 DI 10.1029/2001JD001085 PG 6 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 643PR UT WOS:000180870100010 ER PT J AU Drdla, K Schoeberl, MR Browell, EV AF Drdla, K Schoeberl, MR Browell, EV TI Microphysical modeling of the 1999-2000 Arctic winter: 1. Polar stratospheric clouds, denitrification, and dehydration SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE polar stratospheric clouds; denitrification; dehydration; trajectories; ozone loss ID NITRIC-ACID TRIHYDRATE; IN-SITU MEASUREMENTS; PHYSICAL-CHEMISTRY; LIDAR OBSERVATIONS; PHASE-TRANSITIONS; LOW-TEMPERATURES; OZONE HOLE; AEROSOLS; ICE; NUCLEATION AB [1] The freezing processes that may lead to the formation of solid phase polar stratospheric clouds (PSCs) have been examined to assess their winter-long effects, especially denitrification, in a coupled microphysical/photochemical model. Trajectory simulations spanned from November 1999 to April 2000, using a large set of trajectories which provided representative coverage of the entire Arctic vortex through the period of PSC formation and ozone depletion. A freezing process occurring at temperatures above the ice frost point is shown to be necessary to explain both the occurrence of solid phase PSCs early in the winter and denitrification, especially without dehydration. If freezing only occurs below the ice frost point the primary contributor to denitrification is actually sedimentation of liquid phase PSC particles. The mechanism of a second freezing process, occurring above the ice frost point, can not yet be conclusively determined. Of the cases considered, heterogeneous freezing of the aerosol to form nitric acid trihydrate (NAT) particles best reproduced solid phase PSC formation and observations of widespread denitrification with limited dehydration. The simulations constrain the number of frozen particles to be near either 0.02% or 1% of the total aerosol number; values in between 0.02% and 1% produce more intense denitrification than observed, demonstrating that small changes in the number of frozen particles could exacerbate denitrification. However, this result was contingent upon assuming that the heterogeneous nuclei remain active, producing PSCs, throughout the winter. An idealized homogeneous freezing process was also able to produce NAT PSCs and denitrification (rates of 10(6) -10(7) cm(-3) s(-1) compared favorably with data) but differed from observations in one key aspect: denitrification was more frequently accompanied by dehydration. Nitric acid dihydrate (NAD) particles were less effective than NAT at denitrification, but heterogeneous freezing of 0.1% of the aerosol yielded results marginally consistent with measurements. An important limitation, however, of all the scenarios considered is that they produced more intense and more widespread dehydration than was observed. This suggests that model minimum temperatures (from UK Meteorological Office analyses) were too cold by 1 to 3 K. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Drdla, K (reprint author), NASA, Ames Res Ctr, MS 245-4, Moffett Field, CA 94035 USA. EM katja@aerosol.arc.nasa.gov; schom@odinl.gsfc.nasa.gov; vbrowell@larc.nasa.gov NR 68 TC 2 Z9 2 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 NOV PY 2002 VL 108 IS D5 AR 8312 DI 10.1029/2001JD000782 PG 21 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 643PR UT WOS:000180870100001 ER PT J AU Kawa, SR Bevilacqua, RM Margitan, JJ Douglass, AR Schoeberl, MR Hoppel, KW Sen, B AF Kawa, SR Bevilacqua, RM Margitan, JJ Douglass, AR Schoeberl, MR Hoppel, KW Sen, B TI Interaction between dynamics and chemistry of ozone in the setup phase of the Northern Hemisphere polar vortex SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE ozone; stratosphere; vortex; dynamics; chemistry ID PLANETARY WAVE BREAKING; STRATOSPHERIC OZONE; POTENTIAL VORTICITY; INTERANNUAL VARIABILITY; MIDDLE STRATOSPHERE; WINTER STRATOSPHERE; TRACER TRANSPORT; ARCTIC WINTER; HIGH-LATITUDE; NOVEMBER 1994 AB [1] The morphology and evolution of the stratospheric ozone (O-3) distribution at high latitudes in the Northern Hemisphere (NH) are examined for the late summer and fall seasons of 1999. This time period sets the O-3 initial condition for the SOLVE/THESEO field mission performed during winter 1999/2000. In situ and satellite data are used along with a three-dimensional model of chemistry and transport (CTM) to determine the key processes that control the distribution of O-3 in the lower-to-middle stratosphere. O-3 in the vortex at the beginning of the winter season in late November is found to be nearly constant from 500 to above 800 K with a value at 3 ppmv +/- similar to10%. Values outside the vortex above 550 K are up to a factor of 2 higher and increase significantly with potential temperature. The seasonal time series of data from POAM shows that the relatively low O-3 mixing ratios, which characterize the vortex in late November, are already present at high latitudes at the end of summer in mid-September before the vortex circulation sets up. Analysis of the CTM output shows that the minimum O3 and increase in variance in the middle stratosphere in late summer are the result of (1) stirring of polar concentric O-3 gradients by nascent wave-driven transport and (2) an acceleration of net photochemical loss with decreasing solar illumination. The segregation of low O-3 mixing ratios into the vortex as the circulation strengthens through the fall suggests a possible feedback role between O3 chemistry and the vortex formation dynamics that may need to be better understood in order to make confident predictions of the recovery of NH O-3 at high latitudes. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. USN, Res Lab, Washington, DC 20375 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Kawa, SR (reprint author), NASA, Goddard Space Flight Ctr, Code 916, Greenbelt, MD 20771 USA. EM kawa@maia.gsfc.nasa.gov; bevilacqua@nrl.navy.mil; jjm@caesar.jpl.nasa.gov; douglass@persephone.gsfc.nasa.gov; schom@zephyr.gsfc.nasa.gov; karl.hoppel@nrl.navy.mil; sen@caesar.jpl.nasa.gov RI Douglass, Anne/D-4655-2012; Kawa, Stephan/E-9040-2012 NR 58 TC 10 Z9 10 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 NOV PY 2002 VL 108 IS D5 AR 8310 DI 10.1029/2001JD001527 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 643PR UT WOS:000180870100003 ER PT J AU Kleinbohl, A Bremer, H von Konig, M Kullmann, H Kunzi, KF Goede, APH Browell, EV Grant, WB Toon, GC Blumenstock, T Galle, B Sinnhuber, BM Davies, S AF Kleinbohl, A Bremer, H von Konig, M Kullmann, H Kunzi, KF Goede, APH Browell, EV Grant, WB Toon, GC Blumenstock, T Galle, B Sinnhuber, BM Davies, S TI Vortexwide denitrification of the Arctic polar stratosphere in winter 1999/2000 determined by remote observations SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE denitrification; diabatic descent; HNO3; N2O; ClNO3; airborne submillimeter radiometer ID NITRIC-ACID; OZONE LOSS; FTIR MEASUREMENTS; HNO3; MODEL; HCL; CLONO2; AEROSOL; SESAME; O-3 AB [1] Denitrification has been studied using measurements of stratospheric HNO3 and N2O by the Airborne Submillimeter Radiometer (ASUR), operated on board the NASA DC-8 during SOLVE/THESEO 2000. Lidar measurements taken on board the same aircraft have been used to distinguish between temporary uptake of HNO3 in polar stratospheric clouds (PSCs) and denitrification events. To derive an NOy budget, ClNO3 data by balloonborne and ground-based Fourier transform infrared measurements and a model estimate of NOx + 2N(2)O(5) have been considered. The HNO3 profiles of sporadic ASUR measurements without PSC coverage in January suggest that denitrification had started in the vortex core region by then. Vortexwide denitrification was found in mid-March 2000. Corrected for diabatic descent using the N2O measurements, a vortex-averaged NOy deficit between 1.2 +/- 0.9 ppb at about 16 km altitude and 5.3 +/- 2.7 ppb at about 20.5 km altitude was derived compared to December 1999, based on an observed decrease in HNO3 between 2.2 and 3.5 ppb during this time period. A shift in the NOy partitioning from HNO3 toward ClNO3 of about 0.4 to 0.7 ppb was observed in mid-March compared to December, indicating that chlorine deactivation was occurring. Comparisons with the SLIMCAT three-dimensional chemical transport model applying denitrification schemes based on ice and nitric acid trihydrate particles in equilibrium, respectively, reveal agreement within the error bars at higher altitudes (similar to19 km) but show discrepancies at lower altitudes (similar to16 km). It is suggested that more sophisticated denitrification schemes are needed to generally describe denitrification processes. C1 Univ Bremen, Inst Environm Phys, D-28334 Bremen, Germany. Space Res Org Netherlands, Utrecht, Netherlands. NASA, Langley Res Ctr, Hampton, VA 23681 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Karlsruhe, Forschungszentrum Karlsruhe, Inst Meteorol & Climate Res, D-76021 Karlsruhe, Germany. Swedish Environm Res Inst, S-40258 Gothenburg, Sweden. Univ Leeds, Sch Environm, Leeds LS2 9JT, W Yorkshire, England. RP Univ Bremen, Inst Environm Phys, POB 330440, D-28334 Bremen, Germany. EM kleinb@iup.physik.uni-bremen.de; hbremer@uni-bremen.de; miriam@iup.physik.uni-bremen.de; hkuell@physik.uni-bremen.de; kunzi@physik.uni-bremen.de; albert.goede@knmi.nl; e.v.rowell@larc.nasa.gov; w.b.grant@larc.nasa.gov; toon@mark4sun.jpl.nasa.gov; thomas.blumenstock@imk.fzk.de; bo.galle@ivl.se; bms@iup.physik.uni-bremen.de; stewart@env.leeds.ac.uk RI Weber, Mark/F-1409-2011; Sinnhuber, Miriam/A-7252-2013; Sinnhuber, Bjorn-Martin/A-7007-2013; Blumenstock, Thomas/K-2263-2012; Grant, William/B-8311-2009; Galle, Bo/F-7996-2016 OI Weber, Mark/0000-0001-8217-5450; Sinnhuber, Bjorn-Martin/0000-0001-9608-7320; Grant, William/0000-0002-1439-3285; Galle, Bo/0000-0001-9989-809X NR 48 TC 25 Z9 25 U1 1 U2 5 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 NOV PY 2002 VL 108 IS D5 AR 8305 DI 10.1029/2001JD001042 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 643PR UT WOS:000180870100008 ER PT J AU Mari, C Saut, C Jacob, DJ Ravetta, F Anderson, B Avery, MA Blake, DR Brune, WH Faloona, I Gregory, GL Heikes, BG Sachse, GW Sandholm, ST Singh, HB Talbot, RW Tan, D Vay, S AF Mari, C Saut, C Jacob, DJ Ravetta, F Anderson, B Avery, MA Blake, DR Brune, WH Faloona, I Gregory, GL Heikes, BG Sachse, GW Sandholm, ST Singh, HB Talbot, RW Tan, D Vay, S TI Sources of upper tropospheric HOx over the South Pacific Convergence Zone: A case study SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE HOx; convection; SPCZ; upper troposphere; PEM-TROPICS ID OZONE PRODUCTION; CONVECTIVE INJECTION; LOWER STRATOSPHERE; HYDROGEN RADICALS; ACETONE; PEROXIDES; OH; PHOTOCHEMISTRY; CHEMISTRY; SUGGEST AB [1] A zero-dimensional (0-D) model has been applied to study the sources of hydrogen oxide radicals (HOx = HO2 + OH) in the tropical upper troposphere during the Pacific Exploratory Mission in the tropics (PEM-Tropics B) aircraft mission over the South Pacific in March-April 1999. Observations made across the Southern Pacific Convergence Zone (SPCZ) and the southern branch of the Intertropical Convergence Zone (ITCZ) provided the opportunity to contrast the relative contributions of different sources of HOx, in a nitrogen oxide radical (NOx)-limited regime, in relatively pristine tropical air. The primary sources of HOx vary significantly along the flight track, in correlation with the supply of water vapor. The latitudinal variation of HOx sources is found to be controlled also by the levels of NOx and primary HOx production rates P(HOx). Budget calculations in the 8- to 12-km altitude range show that the reaction O(D-1) + H2O is a major HOx source in the cloud region traversed by the aircraft, including SPCZ and the southern branch of the ITCZ. Production from acetone becomes significant in drier region south of 20degreesS and can become dominant where water vapor mixing ratios lie under 200 ppmv. Over the SPCZ region, in the cloud outflow, CH3 OOH transported by convection accounts for 22% to 64% of the total primary source. Oxidation of methane amplifies the primary HOx source by 1-1.8 in the dry regions. C1 Univ Toulouse 3, CNRS, UMR 5560, Lab Aerol, F-31400 Toulouse, France. Harvard Univ, Div Engn & Appl Sci, Cambridge, MA 02138 USA. Univ Paris 06, CNRS, Serv Aeron, F-75252 Paris 05, France. NASA, Langley Res Ctr, Hampton, VA 23681 USA. Hampton Univ, Dept Phys, Hampton, VA 23668 USA. Univ Calif Irvine, Dept Chem, Irvine, CA 92717 USA. Penn State Univ, Dept Meteorol, University Pk, PA 16802 USA. Natl Ctr Atmospher Res, Div Atmospher Chem, Boulder, CO 80305 USA. Univ Rhode Isl, Ctr Atmospher Chem Studies, Narragansett, RI 02882 USA. Georgia Inst Technol, Atlanta, GA 30332 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ New Hampshire, CSRC, EOS, Durham, NH 03824 USA. RP Univ Toulouse 3, CNRS, UMR 5560, Lab Aerol, F-31400 Toulouse, France. EM marc@aero.obs-mip.fr NR 31 TC 3 Z9 3 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD NOV PY 2002 VL 108 IS D2 AR 8229 DI 10.1029/2000JD000304 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 643PH UT WOS:000180869300003 ER PT J AU Mari, C Saut, C Jacob, DJ Staudt, A Avery, MA Brune, WH Faloona, I Heikes, BG Sachse, GW Sandholm, ST Singh, HB Tan, D AF Mari, C Saut, C Jacob, DJ Staudt, A Avery, MA Brune, WH Faloona, I Heikes, BG Sachse, GW Sandholm, ST Singh, HB Tan, D TI On the relative role of convection, chemistry, and transport over the South Pacific Convergence Zone during PEM-Tropics B: A case study SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE convection; SPCZ; PEM-Tropics; mesoscale model; HOx ID UPPER TROPOSPHERE; HYDROGEN RADICALS; BOUNDARY-LAYER; ODD-HYDROGEN; AIR; HOX; PHOTOCHEMISTRY; SIMULATIONS; FORMULATION; AEROSOLS AB [1] A mesoscale 3D model (Meso-NH) is used to assess the relative importance of convection (transport and scavenging), chemistry, and advection in the vertical redistribution of HOx and their precursors in the upper tropical troposphere. The study is focused on marine deep convection over the South Pacific Convergence Zone (SPCZ) during the PEM-Tropics B Flight 10 aircraft mission. The model reproduces well the HOx mixing ratios. Vertical variations and the contrast between north and south of the SPCZ for O-3 are captured. Convection uplifted O-3-poor air at higher altitude, creating a minimum in the 9-12 km region, in both modeled and observed profiles. The model captured 60% of the observed HCHO variance but fails to reproduce a peak of HCHO mixing ratio at 300 hPa sampled during the northern spirals. Simulated HCHO mixing ratios underestimate observations in the marine boundary layer. In the model, convection is not an efficient process to increase upper tropospheric HCHO, and HCHO is unlikely to serve as a primary source of HOx. Convection plays an important role in the vertical distribution of CH3OOH with efficient vertical transport from the boundary layer to the 10-15 km region where it can act as a primary source of HOx. The SPCZ region acts as a barrier to mixing of tropical and subtropical air at the surface and at high altitudes (above 250 hPa). The 400-270 hPa region over the convergence zone was more permeable, allowing subtropical air masses from the Southern Hemisphere to mix with tropical air from NE of the SPCZ and to be entrained in the SPCZ-related convection. In this altitude range, exchange of subtropical and tropical air also occurs via airflow, bypassing the convective region SW and proceeding toward the north of the SPCZ. C1 Univ Toulouse 3, CNRS, UMR, Lab Aerol, F-31400 Toulouse, France. Harvard Univ, Div Engn & Appl Sci, Cambridge, MA 02138 USA. Hampton Univ, Dept Phys, Hampton, VA 23668 USA. Penn State Univ, Dept Meteorol, University Pk, PA 16802 USA. Natl Ctr Atmospher Res, Div Atmospher Chem, Boulder, CO 80305 USA. Univ Rhode Isl, Ctr Atmospher Chem Studies, Narragansett, RI 02882 USA. NASA, Langley Res Ctr, Aerosp Elect Res Div, Hampton, VA 23681 USA. Georgia Inst Technol, Atlanta, GA 30332 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Mari, C (reprint author), Univ Toulouse 3, CNRS, UMR, Lab Aerol, F-31400 Toulouse, France. EM marc@aero.obs-mip.fr NR 35 TC 0 Z9 0 U1 1 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD NOV PY 2002 VL 108 IS D2 AR 8232 DI 10.1029/2001JD001466 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 643PH UT WOS:000180869300001 ER PT J AU Muller, R Tilmes, S Grooss, JU McKenna, DS Muller, M Schmidt, U Toon, GC Stachnik, RA Margitan, JJ Elkins, JW Arvelius, J Russell, JM AF Muller, R Tilmes, S Grooss, JU McKenna, DS Muller, M Schmidt, U Toon, GC Stachnik, RA Margitan, JJ Elkins, JW Arvelius, J Russell, JM TI Chlorine activation and chemical ozone loss deduced from HALOE and balloon measurements in the Arctic during the winter of 1999-2000 SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE Arctic ozone loss; chemical ozone destruction; vortex remnants; tracer relationships; mixing across vortex edge ID ATMOSPHERE RESEARCH SATELLITE; MICROWAVE LIMB SOUNDER; POLAR VORTEX; STRATOSPHERIC EXPEDITION; OCCULTATION EXPERIMENT; AIRCRAFT MEASUREMENTS; BORNE OBSERVATIONS; DEPLETION; CAMPAIGN; DENITRIFICATION AB [1] We employ Halogen Occultation Experiment (HALOE) observations and balloon-borne measurements (on the large Observations of the Middle Stratosphere [OMS] and Triple balloons, as well as on two small balloons) to investigate ozone loss in the stratospheric vortex in the 1999-2000 Arctic winter. Using HF and CH4 as long-lived tracers, we identify chlorine activation and chemical ozone destruction in the polar vortex. Reference relations, representative of chemically undisturbed "early vortex'' conditions, are derived from the OMS remote and in situ balloon measurements on 19 November and 3 December 1999, respectively. Deviations from this "early vortex'' reference are interpreted as chemical ozone loss and heterogeneous chlorine activation. The observations show an extensive activation of chlorine; in late February 2000, the activation extends to altitudes of 600 K. Between 360 and 450 K chlorine was almost completely activated. At that time, about 70% of the HCl column between 380 and 550 K was converted to active chlorine. Furthermore, the measurements indicate severe chemical ozone loss, with a maximum loss of over 60% in the lower stratosphere (415-465 K) by mid-March 2000. Substantial ozone loss was still observable in vortex remnants in late April 2000 (80 +/- 10 Dobson units [DU] between 380 and 550 K). The average loss in column ozone between 380 and 550 K, inside the vortex core, in mid-March amounted to 84 +/- 13 DU. C1 Forschungszentrum Julich, Inst Stratospharenforsch ICGI, D-52425 Julich, Germany. Goethe Univ Frankfurt, Inst Meteorol & Geophys, D-0325 Frankfurt, Germany. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. NOAA, Climate Monitoring & Diagnost Lab, Boulder, CO 80303 USA. Swedish Inst Space Phys, S-98128 Kiruna, Sweden. Hampton Univ, Ctr Atmospher Sci, Hampton, VA 23668 USA. RP Muller, R (reprint author), Forschungszentrum Julich, Inst Stratospharenforsch ICGI, Postfach 1913, D-52425 Julich, Germany. EM ro.mueller@fz-juelich.de RI Muller, Rolf/A-6669-2013; GrooSS, Jens-Uwe/A-7315-2013; McKenna, Daniel/E-7806-2014 OI Muller, Rolf/0000-0002-5024-9977; GrooSS, Jens-Uwe/0000-0002-9485-866X; McKenna, Daniel/0000-0002-4360-4782 NR 57 TC 20 Z9 20 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 NOV PY 2002 VL 108 IS D5 AR 8302 DI 10.1029/2001JD001423 PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 643PR UT WOS:000180870100011 ER PT J AU Plumb, RA Heres, W Neu, JL Mahowald, NM del Corral, J Toon, GC Ray, E Moore, F Andrews, AE AF Plumb, RA Heres, W Neu, JL Mahowald, NM del Corral, J Toon, GC Ray, E Moore, F Andrews, AE TI Global tracer modeling during SOLVE: High-latitude descent and mixing SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE stratosphere; polar vortex; tracer modeling; stratospheric tracers ID STRATOSPHERIC POLAR VORTEX; IN-SITU MEASUREMENTS; TRANSPORT; AIR; TROPOSPHERE AB [1] We compare tracer observations made during the northern winter of 1999/2000 with the results of simulations with a three-dimensional chemical transport model, driven by assimilated winds. During the course of the winter, very low concentrations of tracers of tropospheric origin (such as N2O) descend into the lower stratosphere within the polar vortex. The altitude of origin of this air has been a matter of debate in the literature; by midwinter, both observations and model results indicate a significant fraction of mesospheric air in the lower stratosphere. Observations from aircraft and balloon flights reveal markers of mesospheric air within the Arctic vortex in the lower and middle stratosphere. An artificial tracer introduced into the model mesosphere at the start of winter descends (being diluted as it does so) all the way down to the 450 K potential temperature surface by March. Modeled tracer-tracer relationships evolve through the winter in a way similar to observations, but the separation between vortex and extravortex curves is exaggerated, suggesting that the model exhibits excessive horizontal mixing within and into the vortex. The tracer-tracer relationships are used to identify partly mixed air as lying, in tracer-tracer space, in a region intermediate between the characteristic vortex and midlatitude relationships. Air lying in a collar region just inside the vortex edge is thus identified as being mixed, and this indicates excessive horizontal mixing in the model across the vortex edge. C1 MIT, Dept Earth Atmospher & Planetary Sci, Cambridge, MA 02139 USA. Univ Calif Santa Barbara, Bren Sch, Santa Barbara, CA 93106 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. NOAA, Climate Monitoring & Diagnost Lab, Boulder, CO 80303 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Plumb, RA (reprint author), MIT, Dept Earth Atmospher & Planetary Sci, Room 54-1726,77 Massachusetts Ave, Cambridge, MA 02139 USA. EM rap@rossby.mit.edu; will@rossby.mit.edu; jessica@rossby.mit.edu; natalie@bren.ucsb.edu; jdcorral@bren.ucsb.edu; toon@mark4sun.jbl.nasa.gov; eray@al.noaa.gov; fmoore@cmdl.noaa.gov; andrews@maia.gsfc.nasa.gov RI Mahowald, Natalie/D-8388-2013; Ray, Eric/D-5941-2013 OI Mahowald, Natalie/0000-0002-2873-997X; Ray, Eric/0000-0001-8727-9849 NR 27 TC 1 Z9 1 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 NOV PY 2002 VL 108 IS D5 AR 8309 DI 10.1029/2001JD001023 PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 643PR UT WOS:000180870100004 ER PT J AU Tuck, AF Hovde, SJ Richard, EC Fahey, DW Gao, RS Bui, TP AF Tuck, AF Hovde, SJ Richard, EC Fahey, DW Gao, RS Bui, TP TI A scaling analysis of ER-2 data in the inner Arctic vortex during January-March 2000 SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE multifractal; ozone; wind; Arctic; stratosphere; vortex ID POLAR STRATOSPHERIC CLOUD; VELOCITY STRUCTURE FUNCTIONS; ANTARCTIC OZONE EXPERIMENT; POTENTIAL VORTICITY; INSITU MEASUREMENTS; UPPER TROPOSPHERE; WINTER; AIRCRAFT; DENITRIFICATION; TURBULENCE AB [1] We apply multifractal analysis using exponents H-1, C-1, and alpha to straight and level stratospheric flight legs of the ER-2 high-altitude research aircraft in the inner vortex (defined as having wind speed <30 ms(-1)). The quantities so analyzed were ozone, wind speed s and temperature T, with the more gappy NOy data being analyzed by H-1 alone. The results for ozone, wind, and temperature are presented as time-dependent data on the three possible planes of the exponents and are compared for the different variables. We relate values of H-1 found in January observations of NOy to those found for ozone. Inner vortex mixing does not remove the small-scale polar stratospheric cloud-induced antipersistence (negative correlation between neighboring intervals for all choices of interval) in ozone by mid-March. Given that large particles were in evidence on all flights examined up to and including 7 March (although in greatly decreased numbers compared to January), this is reasonable. The value of a for ozone did, however, show an increase by mid-March, consistent with the widespread ozone loss evident from time series of histograms of ozone and methane. The histograms also demonstrate that inhomogeneity, with long tails in the probability distributions, is maintained throughout at the 15-25% level in both species. Interpretation is made in terms of polar stratospheric cloud (PSC) induced antipersistence competing with persistence induced by the large-scale insolation field, with the balance increasingly favoring the latter as time proceeds. Results are compared with inner vortex data obtained during earlier ER-2 flights in the Antarctic (1987) and in the Arctic (1989). The inner vortex over Antarctica showed significant increases in H-1 (O-3) and alpha during mid to late September. The correlated increases are consistent with latitudinal excursions of the outer vortex after the cessation of PSC processing, with increased solar exposure increasing H-1 (O-3) and a greater variety of filaments increasing a (O-3). It is concluded that the results have implications for the calculation of photochemical ozone loss in the vortex as a function of time and show that the combined effects of Bolgiano-Obukhov k(-11/5) vertical scaling and Kolmogorov k(-5/3) horizontal scaling predict the scaling behavior of wind speed observed by the aircraft. Rates of change of scaling exponents are linked to horizontal mixing rates and are combined with rates of change of methane to estimate diabatic descent and ozone loss rates for the inner vortex. C1 NOAA, Aeron Lab, Boulder, CO 80303 USA. NASA, Ames Res Ctr, Div Earth Sci, Moffett Field, CA 94035 USA. Univ Colorado, CIRES, Boulder, CO 80309 USA. RP Tuck, AF (reprint author), NOAA, Aeron Lab, R-E-AL6,325 Broadway, Boulder, CO 80303 USA. EM tuck@al.noaa.gov; hovde@al.noaa.gov; richard@al.noaa.gov; fahey@al.noaa.gec; gao@al.noaa.gov; pbui@mail.arc.nasa.gov RI Tuck, Adrian/F-6024-2011; Gao, Ru-Shan/H-7455-2013; Fahey, David/G-4499-2013 OI Tuck, Adrian/0000-0002-2074-0538; Fahey, David/0000-0003-1720-0634 NR 50 TC 13 Z9 13 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 NOV PY 2002 VL 108 IS D5 AR 8306 DI 10.1029/2001JD000879 PG 19 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 643PR UT WOS:000180870100007 ER PT J AU Aires, F Rossow, WB Scott, NA Chedin, A AF Aires, F Rossow, WB Scott, NA Chedin, A TI Remote sensing from the infrared atmospheric sounding interferometer instrument - 1. Compression, denoising, and first-guess retrieval algorithms SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE infrared interferometer; principal component analysis; channel selection ID INDEPENDENT COMPONENT ANALYSIS; TIME-SERIES; SEPARATION; RADIANCES; MODEL AB A principal component analysis (PCA) scheme is developed for treatment of observations from the high spectral resolution Infrared Atmospheric Interferometer (IASI) spaceborne instrument. Compression and denoising of IASI observations are performed using this PCA. This preprocessing methodology also allows for a fast pattern recognition to obtain a first guess from a climatological data set. The performance of the compression, denoising, and multivariate first-guess retrieval are evaluated with a large diversified data set of radiosondes atmospheres including rare events. Overall, the instrumental noise in the overall observed IASI spectrum goes from 0.9 to 0.2 K after denoising. This analysis procedure will be used by Aires et al. [2002c] to retrieve simultaneously temperature, water vapor and ozone atmospheric profiles. C1 NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Ecole Polytech, Meteorol Dynam Lab, F-91128 Palaiseau, France. RP Aires, F (reprint author), Columbia Univ, Dept Appl Phys & Appl Math, New York, NY 10027 USA. EM faires@giss.nasa.gov; wrossow@giss.nasa.gov; scott@arafl.polytechnique.fr; chedin@jungle.polytechnique.fr RI Rossow, William/F-3138-2015 NR 25 TC 52 Z9 54 U1 1 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD NOV PY 2002 VL 107 IS D22 AR 4619 DI 10.1029/2001JD000955 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 643NN UT WOS:000180867500017 ER PT J AU Aires, F Rossow, WB Scott, NA Chedin, A AF Aires, F Rossow, WB Scott, NA Chedin, A TI Remote sensing from the infrared atmospheric sounding interferometer instrument - 2. Simultaneous retrieval of temperature, water vapor, and ozone atmospheric profiles SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE IASI; infrared interferometer; neural networks; principal component analysis ID NEURAL-NETWORK APPROACH AB A fast algorithm is developed to retrieve temperature, water vapor, and ozone atmospheric profile from the high spectral resolution Infrared Atmospheric Sounding Interferometer spaceborne instrument. Compression, denoising, and pattern recognition algorithms have been developed in a companion paper [Aires et al., 2002b]. A principal component analysis neural network using this a guess information is developed here to retrieve simultaneously temperature, water vapor and ozone atmospheric profiles. The performance of the resulting fast and accurate inverse model is evaluated with a climatological data set including rare events: temperature is retrieved with an error less than or equal to1 K, and total amount of water vapor has a mean percentage error between 5 and 7%. Atmospheric water vapor layers are retrieved with an error between 10 and 15% most of the time. The statistics of the ozone retrieval are too optimistic due to a lack of representation of ozone variability in our test data set. C1 NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Ecole Polytech, Meteorol Dynam Lab, F-91128 Palaiseau, France. RP Columbia Univ, Dept Appl Phys & Appl Math, New York, NY 10027 USA. EM faires@giss.nasa.gov; wrossow@giss.nasa.gov; scott@arafl.polytechnique.fr; chedin@jungle.polytechnique.fr RI Rossow, William/F-3138-2015 NR 32 TC 52 Z9 54 U1 1 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD NOV PY 2002 VL 107 IS D22 AR 4620 DI 10.1029/2001JD001591 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 643NN UT WOS:000180867500018 ER PT J AU Buermann, W Wang, YJ Dong, JR Zhou, LM Zeng, XB Dickinson, RE Potter, CS Myneni, RB AF Buermann, W Wang, YJ Dong, JR Zhou, LM Zeng, XB Dickinson, RE Potter, CS Myneni, RB TI Analysis of a multiyear global vegetation leaf area index data set SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE NDVI; leaf area index; interannual variability; ENSO ID SOUTHERN OSCILLATION; SATELLITE DATA; PRECIPITATION; ATMOSPHERE; FORESTS; AVHRR; REFLECTANCE; RADIATION; PATTERNS; CLIMATE AB [1] The analysis of a global data set of monthly leaf area index (LAI), derived from satellite observations of normalized difference vegetation index (NDVI) for the period July 1981 to September 1994, is discussed in this paper. Validation of this retroactive, coarse resolution (8 km) global multiyear data set is a challenging task because repetitive ground measurements from all representative vegetation types are not available. Therefore the magnitudes and interannual variations in the derived LAI fields were assessed as follows. First, the use of a NDVI-based algorithm, as opposed to a more physically based approach, is estimated to result in relative errors in LAI of about 10-20%, which is comparable to the mean uncertainty of AVHRR NDVI data. Second, the satellite LAI values compared reasonably well to ground measurements from three field campaigns. Third, comparison with an existing multiyear LAI data set showed qualitative agreement with regards to interannual variability, although the LAI values of the earlier data were consistently larger than those derived here. Fourth, interannual variations in LAI were evaluated through correlations with climate data sets, e. g., sea surface temperatures and precipitation in tropical semiarid regions known for ENSO impacts, temperature dependence of vegetation growth, and therefore LAI, in the northern latitudes. The general consistency between these independent data sets imbues confidence in the LAI data set, at least for use in large-scale modeling studies. Finally, improvements in near-surface climate simulation are documented in a companion article when satellite LAI values were used in a global climate model. The data set is available to the community via our Web server (http://cybele.bu.edu). C1 Boston Univ, Dept Geog, Boston, MA 02215 USA. Univ Arizona, Inst Atmospher Phys, Tucson, AZ 85721 USA. Georgia Inst Technol, Sch Earth & Atmospher Sci, Atlanta, GA 30332 USA. NASA, Ames Res Ctr, Ecosyst Sci & Technol Branch, Moffett Field, CA 94035 USA. RP Buermann, W (reprint author), Boston Univ, Dept Geog, 675 Commonwealth Ave, Boston, MA 02215 USA. EM buerman@bu.edu RI Zhou, Liming/A-2688-2012; Myneni, Ranga/F-5129-2012 NR 45 TC 48 Z9 49 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 NOV PY 2002 VL 107 IS D22 AR 4646 DI 10.1029/2001JD000975 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 643NN UT WOS:000180867500046 ER PT J AU Callis, LB Natarajan, M Lambeth, JD AF Callis, LB Natarajan, M Lambeth, JD TI Comment on "Solar-atmospheric coupling by electrons (SOLACE), 3, Comparisons of simulations and observations, 1979-1997, issues and implications'' by Linwood B. Callis et al. Reply SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Editorial Material DE precipitating electrons; middle atmospheric odd nitrogen; model-data comparisons; mesospheric NO; stratospheric NO ID STRATOSPHERE C1 NASA, Langley Res Ctr, Div Atmospher Sci, Hampton, VA 23665 USA. Space Applicat Int Corp, Hampton, VA 23666 USA. RP Callis, LB (reprint author), NASA, Langley Res Ctr, Div Atmospher Sci, Hampton, VA 23665 USA. EM l.b.callis@larc.nasa.gov NR 9 TC 3 Z9 3 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 NOV PY 2002 VL 107 IS D22 AR 4634 DI 10.1029/2001JD001464 PG 4 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 643NN UT WOS:000180867500034 ER PT J AU Chou, MD Lee, KT Yang, P AF Chou, MD Lee, KT Yang, P TI Parameterization of shortwave cloud optical properties for a mixture of ice particle habits for use in atmospheric models SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE cloud microphysical and optical properties; transmission and absorption of radiation; radiation and climate ID SINGLE-SCATTERING PROPERTIES; RADIATIVE PROPERTIES; CIRRUS CLOUDS; LIGHT-SCATTERING; CLIMATE MODELS; CRYSTALS; SIZE; ABSORPTION AB On the basis of single-scattering optical properties precomputed with an improved geometric optics method, the bulk absorption coefficient, single-scattering albedo, and asymmetry factor of ice particles have been parameterized as a function of the effective particle size of a mixture of ice habits, the ice water amount, and spectral band. The parameterization has been applied to computing fluxes for sample clouds with various particle size distributions and assumed mixtures of particle habits. It is found that flux calculations are not overly sensitive to the assumed particle habits if the definition of the effective particle size is consistent with the particle habits on which the parameterization is based. Otherwise, the error in the flux calculations could reach a magnitude unacceptable for climate studies. Different from many previous studies, the parameterization requires only an effective particle size representing all ice habits in a cloud layer but not the effective size of individual ice habits. C1 NASA, Atmospheres Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Natl Kangnung Univ, Dept Atmospher & Environm Sci, Kangnung, South Korea. Texas A&M Univ, Dept Atmospher Sci, College Stn, TX 77843 USA. RP Chou, MD (reprint author), NASA, Atmospheres Lab, Goddard Space Flight Ctr, Mail Code 913,Bldg 22,Room C323, Greenbelt, MD 20771 USA. EM chou@climate.gsfc.nasa.gov; ktlee@knusun.kangnung.ac.kr; pyang@ariel.met.tamu.edu RI Yang, Ping/B-4590-2011 NR 26 TC 21 Z9 22 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 NOV PY 2002 VL 107 IS D21 AR 4600 DI 10.1029/2002JD002061 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 643KK UT WOS:000180860300051 ER PT J AU Chou, WW Wofsy, SC Harriss, RC Lin, JC Gerbig, C Sachse, GW AF Chou, WW Wofsy, SC Harriss, RC Lin, JC Gerbig, C Sachse, GW TI Net fluxes of CO2 in Amazonia derived from aircraft observations SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE carbon cycle; Amazon Basin; aircraft measurements ID ATMOSPHERIC CO2; CARBON-DIOXIDE; TROPICAL FORESTS; BALANCE; BUDGET; BASIN; VARIABILITY; PERSPECTIVE; DELTA-C-13; ECOSYSTEMS AB A conceptual framework is developed using atmospheric measurements from aircraft to determine fluxes of CO2 from a continental land area. The concepts are applied to measurements of CO2, O-3, and CO concentrations from the Amazon Boundary Layer Experiment (ABLE-2B, April-May 1987) to estimate fluxes of CO2 for central and eastern Amazonia late in the wet season of 1987. We observed that column amounts of CO2 from 0 to 3 km decreased during the day over Amazonia at the average rate of -6.3+/-1 mumol m(-2) s(-1), corresponding to an uptake flux modestly smaller than the daytime uptake (-10.2 mumol m(-2) s(-1)) at a flux tower in the study area. The estimated net flux of CO2, integrated over 24 hours, was -0.03+/-0.2 mumol m(-2) s(-1), indicating that the carbon budget of a substantial area of central Amazonia was close to balance in April 1987. We argue that net CO2 fluxes on the continental scale of Amazonia, with its heterogeneous landscape and large areas of inundation, are strongly modified by the influence of seasonal hydrological factors that enhance respiration and decomposition in forests and wetlands, offsetting growth of forest trees in the wet season. C1 Harvard Univ, Dept Earth & Planetary Sci, Cambridge, MA 02138 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Chou, WW (reprint author), Harvard Univ, Dept Earth & Planetary Sci, 29 Oxford St, Cambridge, MA 02138 USA. EM scw@io.harvard.edu; harriss@ucar.edu; g.w.sachse@larc.nasa.gov RI Gerbig, Christoph/L-3532-2013 OI Gerbig, Christoph/0000-0002-1112-8603 NR 39 TC 36 Z9 37 U1 1 U2 10 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD NOV PY 2002 VL 107 IS D22 AR 4614 DI 10.1029/2001JD001295 PG 20 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 643NN UT WOS:000180867500012 ER PT J AU Chuang, CC Penner, JE Prospero, JM Grant, KE Rau, GH Kawamoto, K AF Chuang, CC Penner, JE Prospero, JM Grant, KE Rau, GH Kawamoto, K TI Cloud susceptibility and the first aerosol indirect forcing: Sensitivity to black carbon and aerosol concentrations SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID GENERAL-CIRCULATION MODEL; EFFECTIVE-MEDIUM APPROXIMATIONS; ANTHROPOGENIC SULFATE; OPTICAL-PROPERTIES; BIOGENIC HYDROCARBONS; SIZE DISTRIBUTIONS; DIMETHYL SULFIDE; GLOBAL INVENTORY; EFFECTIVE-RADIUS; SOLAR-RADIATION AB [1] Present-day global anthropogenic emissions contribute more than half of the mass in submicron particles primarily due to sulfate and carbonaceous aerosol components derived from fossil fuel combustion and biomass burning. These anthropogenic aerosols increase cloud drop number concentration and cloud albedo. Here, we use an improved version of the fully coupled climate/chemistry models to investigate cloud susceptibility and the first indirect effect of anthropogenic aerosols (the Twomey effect). We examine the correspondence between the model simulation of cloud susceptibility and that inferred from satellite measurements to test whether our simulated aerosol concentrations and aerosol/cloud interactions give a faithful representation of these features. This comparison provides an overall measure of the adequacy of cloud cover and drop concentrations. We also address the impact of black carbon absorption in clouds on the first indirect forcing and examine the sensitivity of the forcing to different representations of natural aerosols. We find that including this absorption does not change the global forcing by more than 0.07 W m(-2), but that locally it could decrease the forcing by as much as 0.7 W m(-2) in regions where black carbon emissions are pronounced. Because of the nonlinear relationship between cloud drop number and aerosol number concentrations, the total forcing does not equal the sum of the forcing from each individual source. Our estimated total first indirect forcing is -1.85 W m(-2), with -0.30 W m(-2) associated with anthropogenic sulfate, -1.16 W m(-2) associated with carbonaceous aerosols from biomass burning, and -0.52 W m(-2) associated with carbonaceous aerosols from fossil fuel combustion. Estimates of forcing by sulfate and total carbonaceous aerosols increase to -0.31 and -1.67 W m(-2), respectively, if natural emissions of organic aerosols are only 8.4 Tg yr(-1), but decrease to -0.26 and -1.27 W m(-2) if they are as large as 42 Tg yr(-1). Even larger estimates of forcing are derived if dust and sea-salt emissions are not included. The effect of aerosol abundance on cloud life cycle may be important but is not treated in this study. C1 Lawrence Livermore Natl Lab, Div Atmospher Sci, Livermore, CA 94550 USA. Univ Michigan, Dept Atmospher Ocean & Space Sci, Ann Arbor, MI 48109 USA. Univ Miami, Cooperat Inst Marine & Atmospher Studies, Miami, FL 33149 USA. Univ Calif Santa Cruz, Inst Marine Sci, Santa Cruz, CA 95064 USA. Virginia Polytech Inst & State Univ, Blacksburg, VA 24061 USA. NASA, Langley Res Ctr, Div Atmospher Sci, Hampton, VA 23681 USA. RP Chuang, CC (reprint author), Lawrence Livermore Natl Lab, Div Atmospher Sci, Livermore, CA 94550 USA. EM chuang@llnl.gov RI chuang, cathy/H-4814-2012; Penner, Joyce/J-1719-2012; OI Prospero, Joseph/0000-0003-3608-6160 NR 76 TC 82 Z9 86 U1 2 U2 19 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 NOV PY 2002 VL 107 IS D21 AR 4564 DI 10.1029/2000JD000215 PG 23 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 643KK UT WOS:000180860300016 ER PT J AU Clough, SA Worden, JR Brown, PD Shephard, MW Rinsland, CP Beer, R AF Clough, SA Worden, JR Brown, PD Shephard, MW Rinsland, CP Beer, R TI Retrieval of tropospheric ozone from simulations of limb spectral radiances as observed from space SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE remote sensing; ozone limb retrievals; tropospheric ozone; atmospheric constituents; Thermal Emission Spectrometer (TES) ID SATELLITE AB The frequent and direct remote sensing of the tropospheric ozone profile is a critical environmental measurement to be performed on a global scale by future satellite instruments. An approach has been developed for the retrieval of tropospheric ozone profiles from 9.6 mum limb-viewing clear-sky radiances generated for the spectral resolution and signal-to-noise of the Tropospheric Emission Spectrometer (TES). TES is a high-resolution Fourier transform spectrometer under development for NASA's Earth Observing System Aura platform (http://eos-chem.gsfc.nasa.gov/). The simulated radiance spectra are calculated from northern hemisphere midlatitude lidar profile measurements. The ozone profile retrieval and the associated errors are obtained as a function of atmospheric pressure level using the method of nonlinear least squares with regularization. In order to accelerate convergence a two-stage strategy has been applied in which the full profile retrieval has been preceded by a shape retrieval involving a smaller set of near independent parameters. Our analysis indicates that the O-3 profile can be retrieved from the TES limb measurements with a relative uncertainty of 5% (1sigma) in the middle and upper troposphere. C1 Atmospher & Environm Res Inc, Lexington, MA 02421 USA. NASA, Langley Res Ctr, Div Atmospher Sci, Hampton, VA USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Clough, SA (reprint author), Atmospher & Environm Res Inc, 131 Hartwell Ave, Lexington, MA 02421 USA. EM sclough@aer.com; jworden@jpl.nasa.gov; pbrown@sherwoodlane.com; mshepar@aer.com; rinsland@mipsbox.larc.nasa.gov; reinhard.beer@jpl.nasa.gov NR 13 TC 8 Z9 8 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 NOV PY 2002 VL 107 IS D21 AR 4589 DI 10.1029/2001JD001307 PG 5 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 643KK UT WOS:000180860300041 ER PT J AU Eldering, A Ogren, JA Chowdhury, Z Hughes, LS Cass, GR AF Eldering, A Ogren, JA Chowdhury, Z Hughes, LS Cass, GR TI Aerosol optical properties during INDOEX based on measured aerosol particle size and composition SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE aerosol; INDOEX; single-scattering albedo; extinction coefficient ID INDIAN-OCEAN EXPERIMENT; SCATTERING; VISIBILITY; NEPHELOMETER; MODEL AB [1] The light scattering and light absorption as a function of wavelength and relative humidity due to aerosols measured at the Kaashidhoo Climate Observatory in the Republic of the Maldives during the INDOEX field campaign has been calculated. Using size-segregated measurements of aerosol chemical composition, calculated light scattering and absorption has been evaluated against measurements of light scattering and absorption. Light scattering coefficients are predicted to within a few percent over relative humidities of 20-90%. Single scattering albedos calculated from the measured elemental carbon size distributions and concentrations in conjunction with other aerosol species have a relative error of 4.0% when compared to measured values. The single scattering albedo for the aerosols measured during INDOEX is both predicted and observed to be about 0.86 at an ambient relative humidity of 80%. These results demonstrate that the light scattering, light absorption, and hence climate forcing due to aerosols over the Indian Ocean are consistent with the chemical and physical properties of the aerosol at that location. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. NOAA, Climate Monitoring & Diagnost Lab, Boulder, CO 80303 USA. CALTECH, Pasadena, CA 91125 USA. Georgia Inst Technol, Sch Earth & Atmospher Sci, Atlanta, GA 30332 USA. RP Eldering, A (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM Annmarie.Eldering@jpl.nasa.gov; John.A.Ogren@noaa.gov; zohir@caltech.edu; lara@gertler.com RI Ogren, John/M-8255-2015 OI Ogren, John/0000-0002-7895-9583 NR 25 TC 20 Z9 21 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 NOV PY 2002 VL 107 IS D22 AR 8001 DI 10.1029/2001JD001572 PG 8 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 643NN UT WOS:000180867500031 ER PT J AU Fioletov, VE Bodeker, GE Miller, AJ McPeters, RD Stolarski, R AF Fioletov, VE Bodeker, GE Miller, AJ McPeters, RD Stolarski, R TI Global and zonal total ozone variations estimated from ground-based and satellite measurements: 1964-2000 SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE ozone; Dobson; Brewer; TOMS; SBUV ID RECORD-LOW OZONE; QUASI-BIENNIAL OSCILLATION; NEW-ZEALAND; STRATOSPHERIC OZONE; PINATUBO AEROSOLS; DOBSON NETWORK; COLUMN OZONE; TRENDS; TOMS; NIMBUS-7 AB [1] Six data sets of monthly average zonal total ozone were intercompared and then used to estimate latitudinal and global total ozone temporal variations and trends. The data sets were prepared by different groups and are based on TOMS, SBUV-SBUV/2, GOME, and ground-based measurements. Different approaches have been used to homogenize the records over the period 1979-2000. Systematic differences of up to 3% were found between different data sets for zonal and global total ozone area weighted average values. However, when these systematic differences were removed by deseasonalizing the data, the residuals agreed to within +/-0.5% of the long-term mean ozone values. All data sets show changes in the rate of the total ozone decline in recent years. While global ozone was fairly constant during the 1990s, the average values of the 1990s are about 2-3% lower than those of the late 1970s. About 38% of the global ozone is located between 25 S and 25degreesN where the data show no decline. The strongest decline and the largest variability occur over the 35degreesN-60degreesN zone during the winter-spring season with the largest negative deviations occurring in 1993 and 1995. The decline in autumn is much smaller at these latitudes. Over the 35degreesS-60degreesS zone the ozone decline shows less seasonal dependence, and the largest deviations there were observed in 1985 and 1997. Sliding 11-year trends were calculated to estimate ozone changes over different time intervals. The first interval was from 1964 to 1974, and the last interval was from 1990 to 2000. The steepest year-round trends, of up to -5% per decade, occurred in the 11-year periods ending between 1992 and 1997 over the 35degrees-60degreesN zone and between 1985 and 1993 over the 35degrees-55degreesS zone. More recent 11-year trends have smaller declines. C1 Environm Canada, Downsview, ON M3H 5T4, Canada. Natl Inst Water & Atmospher Res, Omakau, New Zealand. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NOAA, Climate Predict Ctr, Washington, DC 20233 USA. RP Fioletov, VE (reprint author), Environm Canada, 4905 Dufferin St, Downsview, ON M3H 5T4, Canada. EM vitali.fioletov@ec.gc.ca; g.bodeker@niwa.cri.nz; miller@climon.wwb.noaa.gov; mcpeters@wrabbit.gsfc.nasa.gov; stolarski@polska.gsfc.nasa.gov RI Stolarski, Richard/B-8499-2013; McPeters, Richard/G-4955-2013 OI Stolarski, Richard/0000-0001-8722-4012; McPeters, Richard/0000-0002-8926-8462 NR 69 TC 144 Z9 148 U1 3 U2 11 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD NOV PY 2002 VL 107 IS D22 AR 4647 DI 10.1029/2001JD001350 PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 643NN UT WOS:000180867500047 ER PT J AU Gates, AM Avallone, LM Toohey, DW Rutter, AP Whitefield, PD Hagen, DE Hopkins, AR Ross, MN Zittel, PF Thompson, TL Herman, RL Friedl, RR AF Gates, AM Avallone, LM Toohey, DW Rutter, AP Whitefield, PD Hagen, DE Hopkins, AR Ross, MN Zittel, PF Thompson, TL Herman, RL Friedl, RR TI In situ measurements of carbon dioxide, 0.37-4.0 mu m particles, and water vapor in the stratospheric plumes of small rockets SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE carbon dioxide (CO2); H2O; ozone depletion; rocket plumes; emissions ID INDUCED ICE PARTICLES; ALUMINUM-OXIDE; ARCTIC STRATOSPHERE; NITRIC-ACID; EXHAUST; AIRCRAFT; OZONE; H2O; HCL; SPECTROMETER AB [1] Carbon dioxide (CO2) and large particles (0.37-4.0 mum) were measured in the stratospheric plume wakes of three rockets, an Atlas IIAS, a Delta II, and an Athena II. The correlations between CO2 mass and particle number densities in each plume are consistent with the unique combination of solid and liquid engine emissions of each rocket. Measured size distributions indicate a 1.1 mum mode with density of 2 g cm(-3), consistent with spherical alumina particles emitted by solid rocket motors. Disagreement between the measured size distributions and the mean sizes inferred from the known alumina and CO2 emission indices and an observed increase in the particle number emission index with altitude are evidence for large particle oversampling effects and the presence of condensed volatile compounds within the particle population. Direct evidence for the latter is a persistent similar to0.5-1 part per million (ppm) shortfall of water vapor relative to CO2 measured in the plume of the Athena II rocket based on the expected H2O/CO2 emission ratio. Although pure ice particles would not persist at the conditions of the measurements, a more stable coating of HNO3 (as either nitric acid trihydrate or as a liquid layer) could have reduced the sublimation rate of the underlying ice, thereby increasing the lifetimes of volatile particles within the plume. If confirmed, such a process would have important implications for the radiative and chemical properties of rocket plumes, including global ozone depletion associated with rocket launch activities. C1 Univ Colorado, Atmospher & Space Phys Lab, Boulder, CO 80309 USA. Univ Colorado, Program Atmospher & Ocean Sci, Boulder, CO 80309 USA. Univ Missouri, Cloud & Aerosol Sci Lab, Rolla, MO USA. Univ Colorado, Dept Chem, Boulder, CO 80309 USA. Univ Colorado, Dept Phys, Boulder, CO 80309 USA. Aerosp Corp, Los Angeles, CA 90009 USA. NOAA, Aeron Lab, Boulder, CO 80305 USA. Jet Propuls Lab, Pasadena, CA 91109 USA. RP Gates, AM (reprint author), Univ Colorado, Atmospher & Space Phys Lab, 590 UCB, Boulder, CO 80309 USA. EM amelia.gates@colorado.edu; avallone@lasp.colorado.edu; toohey@colorado.edu; arutter@umr.edu; pwhite@umr.edu; hagen@umr.edu; martin.n.ross@aero.org; paul.f.zittel@aero.org; thomas.l.thompson@al.noaa.gov; robert.l.herman@jpl.nasa.gov; randall.r.friedl@jpl.nasa.gov RI Toohey, Darin/A-4267-2008; Herman, Robert/H-9389-2012 OI Toohey, Darin/0000-0003-2853-1068; Herman, Robert/0000-0001-7063-6424 NR 34 TC 7 Z9 7 U1 1 U2 5 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD NOV PY 2002 VL 107 IS D22 AR 4649 DI 10.1029/2002JD002121 PG 10 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 643NN UT WOS:000180867500049 ER PT J AU Gu, GJ Zhang, CD AF Gu, GJ Zhang, CD TI Cloud components of the Intertropical Convergence Zone SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE ITCZ; synoptic-scale disturbances; tropical convection ID SYNOPTIC-SCALE DISTURBANCES; WAVE DISTURBANCES; PACIFIC; SATELLITE; TEMPERATURE; CIRCULATION; BUDGET; ITCZ AB [1] This study explores the roles of different synoptic-scale cloud systems in the making of the Intertropical Convergence Zone (ITCZ). Outgoing longwave radiation (OLR) data are used to represent both the mean ITCZ and cloud systems. An OLR threshold of 205 W m(-2) is used to distinguish daily mean deep convective clouds from nondeep clouds. Zonally moving synoptic-scale cloud systems are identified through a cloud-tracking method. Mean OLR of the ITCZ is decomposed into five components: westward and eastward moving synoptic-scale deep convective clouds, random (nonpropagating) deep convective clouds, nondeep clouds, and clear-sky backgrounds. Hypothetical ITCZs, each composed of one of the cloud components and the clear-sky background, are constructed and compared. The largest synoptic-scale cloud constituents of the ITCZ are nondeep clouds and deep clouds with no persistent tendency of zonal propagation. Each of the two comprises about 40-45% of total cloud signals in the ITCZ. A weak ITCZ could exist solely because of westward propagating, synoptic-scale, deep-convective clouds. In reality, these westward propagating clouds contribute 25-40% of deep convective clouds and 10-20% of total clouds in the ITCZ. Contributions from eastward propagating synoptic-scale clouds are much smaller (8% of the deep convective clouds and less than 5% of total clouds in the ITCZ). An ITCZ without any zonally propagating synoptic-scale deep convective clouds would be diffused in latitude. The cloud compositions in the ITCZ and other tropical convective zones are compared. Their discrepancies indicate fundamental characteristics in large-scale environments for the cloud components in different regions. C1 Univ Miami, Rosenstiel Sch Marine & Atmospher Sci, Meteorol & Phys Oceanog Div, Miami, FL 33149 USA. RP Gu, GJ (reprint author), Univ Maryland Baltimore Cty, Goddard Earth Sci & Technol Ctr, Baltimore, MD 21228 USA. EM ggu@agnes.gsfc.nasa.gov; czhang@rsmas.miami.edu NR 31 TC 16 Z9 17 U1 3 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 NOV PY 2002 VL 107 IS D21 AR 4565 DI 10.1029/2002JD002089 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 643KK UT WOS:000180860300017 ER PT J AU Li, QB Jacob, DJ Fairlie, TD Liu, HY Martin, RV Yantosca, RM AF Li, QB Jacob, DJ Fairlie, TD Liu, HY Martin, RV Yantosca, RM TI Stratospheric versus pollution influences on ozone at Bermuda: Reconciling past analyses SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID EASTERN NORTH-ATLANTIC; CHEMICAL TRACER MODEL; TROPOSPHERIC OZONE; SURFACE OZONE; CARBON-MONOXIDE; TRANSPORT MODEL; 3-D MODELS; CHEMISTRY; CLIMATOLOGY; MAXIMUM AB Conflicting interpretations of the spring ozone maximum observed at Bermuda (32degreesN, 65degreesW) have fueled the debate on stratospheric influence versus tropospheric production as sources of tropospheric ozone. We use a global three-dimensional (3-D) model of tropospheric ozone-NOx-hydrocarbon chemistry driven by assimilated meteorological observations to reconcile these past interpretations. The model reproduces the observed seasonal cycle of surface ozone at Bermuda and captures the springtime day-to-day variability (r=0. 82, n=122, p<0.001) driven by high-ozone events. We find that transport of North American pollution behind cold fronts is the principal contributor to springtime surface ozone at Bermuda and is responsible for all the high-ozone events. The model reproduces the observed positive correlations of surface ozone with Be-7 and Pb-210 at Bermuda; the correlation with Be-7 reflects the strong subsidence behind cold fronts, resulting in the mixing of middle-tropospheric air with continental outflow in the air arriving at Bermuda, as indicated by the positive Be-7-Pb-210 correlation. This mixing appears to have been an obfuscating factor in past interpretations of subsiding back-trajectories at Bermuda as evidence for a stratospheric or upper tropospheric origin for ozone. Isentropic back-trajectories computed in our model reproduce the previously reported subsidence associated with high-ozone events. Even in the free troposphere, we find that the stratosphere contributes less than 5 ppbv (<10%) to spring ozone over Bermuda. Positive O-3-Be-7 and negative O-3-Pb-210 correlations observed at Tenerife (28degreesN, 16degreesW, 2.4 km) in summer are reproduced by the model and are consistent with a middle-ropospheric source of ozone, not an upper tropospheric or stratospheric source as previously suggested. A regional budget for the North Atlantic in spring indicates that the stratosphere contributes less than 10 ppbv ozone (<5%) below 500 hPa, while the lower troposphere contributes 20-40 ppbv ozone throughout the troposphere. C1 Harvard Univ, Dept Earth & Planetary Sci, Cambridge, MA 02138 USA. Harvard Univ, Div Engn & Appl Sci, Cambridge, MA 02138 USA. NASA, Langley Res Ctr, Hampton, VA 23665 USA. RP Li, QB (reprint author), Harvard Univ, Dept Earth & Planetary Sci, 29 Oxford St, Cambridge, MA 02138 USA. EM qli@io.harvard.edu; djj@io.harvard.edu; tdf@io.harvard.edu; hyl@io.harvard.edu; rvm@io.harvard.edu; bmy@io.harvard.edu RI Martin, Randall/A-2051-2008; Liu, Hongyu/A-5867-2008; Martin, Randall/C-1205-2014 OI Martin, Randall/0000-0003-2632-8402 NR 57 TC 41 Z9 41 U1 1 U2 5 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD NOV PY 2002 VL 107 IS D22 AR 4611 DI 10.1029/2002JD002138 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 643NN UT WOS:000180867500009 ER PT J AU Liu, HY Jacob, DJ Chan, LY Oltmans, SJ Bey, I Yantosca, RM Harris, JM Duncan, BN Martin, RV AF Liu, HY Jacob, DJ Chan, LY Oltmans, SJ Bey, I Yantosca, RM Harris, JM Duncan, BN Martin, RV TI Sources of tropospheric ozone along the Asian Pacific Rim: An analysis of ozonesonde observations SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE pollution transport; seasonal variation; case study ID BIOMASS-BURNING EMISSIONS; HONG-KONG; SURFACE OZONE; NORTHERN-HEMISPHERE; GENERAL-CIRCULATION; SEASONAL BEHAVIOR; BOUNDARY-LAYER; FLOW PATTERNS; 3-D MODELS; EAST-ASIA AB [1] The sources contributing to tropospheric ozone over the Asian Pacific Rim in different seasons are quantified by analysis of Hong Kong and Japanese ozonesonde observations with a global three-dimensional (3-D) chemical transport model (GEOS-CHEM) driven by assimilated meteorological observations. Particular focus is placed on the extensive observations available from Hong Kong in 1996. In the middle-upper troposphere (MTUT), maximum Asian pollution influence along the Pacific Rim occurs in summer, reflecting rapid convective transport of surface pollution. In the lower troposphere (LT) the season of maximum Asian pollution influence shifts to summer at midlatitudes from fall at low latitudes due to monsoonal influence. The UT ozone minimum and high variability observed over Hong Kong in winter reflects frequent tropical intrusions alternating with stratospheric intrusions. Asian biomass burning makes a major contribution to ozone at <32 degrees N in spring. Maximum European pollution influence (<5 ppbv) occurs in spring in the LT. North American pollution influence exceeds European influence in the UT-MT, reflecting the uplift from convection and the warm conveyor belts over the eastern seaboard of North America. African outflow makes a major contribution to ozone in the low-latitude MT-UT over the Pacific Rim during November-April. Lightning influence over the Pacific Rim is minimum in summer due to westward UT transport at low latitudes associated with the Tibetan anticyclone. The Asian outflow flux of ozone to the Pacific is maximum in spring and fall and includes a major contribution from Asian anthropogenic sources year-round. C1 Harvard Univ, Dept Earth & Planetary Sci, Cambridge, MA 02138 USA. Harvard Univ, Div Engn & Appl Sci, Cambridge, MA 02138 USA. Hong Kong Polytech Univ, Dept Civil & Struct Engn, Kowloon, Hong Kong, Peoples R China. NOAA, Climate Monitoring & Diagnost Lab, Boulder, CO 80303 USA. RP Liu, HY (reprint author), NASA, Langley Res Ctr, Inst Comp Applicat Sci & Engn, Mail Stop Chem & Dynam Branch, Hampton, VA 23681 USA. EM hyl@post.harvard.edu; djj@io.harvard.edu; celychan@polyu.edu.hk; samuel.j.oltmans@noaa.gov; isabelle.bey@epfl.ch; bmy@io.harvard.edu; joyce.m.harris@noaa.gov; bryan.duncan@epfl.ch; rvm@io.harvard.edu RI Martin, Randall/A-2051-2008; Liu, Hongyu/A-5867-2008; Duncan, Bryan/A-5962-2011; Martin, Randall/C-1205-2014; Chem, GEOS/C-5595-2014 OI Martin, Randall/0000-0003-2632-8402; NR 73 TC 85 Z9 88 U1 0 U2 10 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD NOV PY 2002 VL 107 IS D21 AR 4573 DI 10.1029/2001JD002005 PG 24 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 643KK UT WOS:000180860300025 ER PT J AU Mahowald, NM Zender, CS Luo, C Savoie, D Torres, O del Corral, J AF Mahowald, NM Zender, CS Luo, C Savoie, D Torres, O del Corral, J TI Understanding the 30-year Barbados desert dust record SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE mineral aerosols; desert dust; North Africa; desertification ID NORTH-ATLANTIC; MINERAL DUST; FRICTION VELOCITY; OPTICAL-THICKNESS; WIND EROSION; LAND-USE; AEROSOLS; MODEL; VARIABILITY; THRESHOLD AB [1] Atmospheric mineral aerosols influence climate and biogeochemistry, and thus understanding the impact of humans on mineral aerosols is important. Our longest continuous record of in situ atmospheric desert dust measurements comes from Barbados, which shows fluctuations of a factor of 4 in surface mass concentrations between the 1960s and the 1980s [Prospero and Nees, 1986]. Understanding fluctuations this large should help us understand how natural and anthropogenic factors change mineral aerosol sources, transport, distributions, and deposition, although we are limited in our ability to interpret the results as there is a quantitative record only at one location. We test the hypothesis that dry topographic lows (and not disturbed sources such as cultivated areas or new desert regions) are the sources of desert dust, using a hierarchy of models as well meteorological data sets to look at decadal scale changes in the North Atlantic desert dust. We find that the inclusion of a disturbed source improves our simulations in many (but not all) comparisons. Unfortunately, we are severely limited by the accuracy of the available data sets and models in making definitive statements about the role of disturbed sources or anthropogenic activity in changing the atmospheric desert dust cycle. Processes that might change the size or intensity of desert dust sources in North Africa (such as new sources due to desertification or land use) may be difficult to distinguish from topographic low sources in models due to their similar geographical locations and impact on atmospheric aerosol distributions. C1 Univ Calif Santa Barbara, Bren Sch Environm Sci & Management, Santa Barbara, CA 93106 USA. Univ Calif Santa Barbara, Inst Computat Earth Syst Sci, Santa Barbara, CA 93106 USA. Univ Calif Irvine, Dept Earth Syst Sci, Irvine, CA 92697 USA. Univ Miami, Rosenstiel Sch Marine & Atmospher Sci Marine & At, Miami, FL 33149 USA. Univ Maryland Baltimore Cty, Joint Ctr Earth Syst Technol, Baltimore, MD 20771 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Mahowald, NM (reprint author), Univ Calif Santa Barbara, Bren Sch Environm Sci & Management, Santa Barbara, CA 93106 USA. EM natalie@bren.ucsb.edu RI Zender, Charles/D-4485-2012; Mahowald, Natalie/D-8388-2013; Torres, Omar/G-4929-2013 OI Zender, Charles/0000-0003-0129-8024; Mahowald, Natalie/0000-0002-2873-997X; NR 56 TC 74 Z9 74 U1 1 U2 9 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD NOV PY 2002 VL 107 IS D21 AR 4561 DI 10.1029/2002JD002097 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 643KK UT WOS:000180860300013 ER PT J AU Olsen, MA Douglass, AR Schoeberl, MR AF Olsen, MA Douglass, AR Schoeberl, MR TI Estimating downward cross-tropopause ozone flux using column ozone and potential vorticity SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE stratosphere-troposphere exchange; ozone; total column ozone; cross-tropopause transport; ozone transport ID STRATOSPHERE-TROPOSPHERE EXCHANGE; GENERAL-CIRCULATION MODEL; CHEMICAL-TRANSPORT MODEL; MASS; CHEMISTRY; MESOSCALE; CYCLONE; BUDGET; TRACER; LIDAR AB [1] A new method of estimating the downward ozone flux across the midlatitude tropopause is introduced. The algorithm derives the estimate from total column ozone observations. Vertical information is given by analysis potential vorticity fields. This method yields an annual estimate of 500 +/- 140 Tg yr(-1) stratospheric injection of ozone into the northern hemisphere, midlatitude troposphere. The downward ozone flux exhibits the expected spring maximum and autumn minimum. The annual distribution of the cross-tropopause ozone transport by latitude is consistent with the seasonal frequency and distribution of baroclinic systems. This algorithm also produces localized results and can thus be applied to a single case or global studies. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Olsen, MA (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. EM olsen@code916.gsfc.nasa.gov RI Douglass, Anne/D-4655-2012 NR 29 TC 17 Z9 17 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 NOV PY 2002 VL 107 IS D22 AR 4636 DI 10.1029/2001JD002041 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 643NN UT WOS:000180867500035 ER PT J AU Reichardt, J Reichardt, S Hess, M McGee, TJ AF Reichardt, J Reichardt, S Hess, M McGee, TJ TI Correlations among the optical properties of cirrus-cloud particles: Microphysical interpretation SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article ID HEXAGONAL ICE CRYSTALS; RAMAN-LIDAR; CLIMATIC IMPLICATIONS; POLARIZATION LIDAR; LIGHT-SCATTERING; AEROSOL; BACKSCATTER; EXTINCTION; FACILITY; DEPOLARIZATION AB [1] Cirrus measurements obtained with a ground-based polarization Raman lidar at 67.9degreesN in January 1997 reveal a strong positive correlation between the particle optical properties, specifically depolarization ratio delta(par) and extinction-to-backscatter (lidar) ratio S-par, for delta(par) < similar to 40%, and an anticorrelation for delta(par) > similar to40%. Over the duration of the measurements, both particle properties vary systematically. This effect is particularly pronounced in the case of delta(par), which decreases significantly with time. The analysis of lidar humidity and radiosonde temperature data shows that the measured optical properties stem from scattering by dry solid ice particles, while scattering by supercooled droplets, or by wetted or subliming ice particles, can be excluded. For the microphysical interpretation of the lidar measurements, ray-tracing computations of particle scattering properties have been used. The comparison with the theoretical data suggests that the observed cirrus data can be interpreted in terms of size, shape, and growth of the cirrus particles, the latter under the assumption that the lidar measurements of consecutive cloud segments can be mapped on the temporal development of a single cloud parcel moving along its trajectory: Near the cloud top in the early stage of cirrus development, light scattering by nearly isometric particles that have the optical characteristics of hexagonal columns (short, column-like particles) is dominant. Over time, the ice particles grow, and as the cloud base height extends to lower altitudes characterized by warmer temperatures they become morphologically diverse. For large S-par and depolarization values of similar to40%, the scattering contributions of column- and plate-like particles are roughly the same. In the lower ranges of the cirrus clouds, light scattering is predominantly by plate-like ice particles. This interpretation assumes random orientation of the cirrus particles. Simulations with a simple model suggest, however, that the positive correlation between S-par and delta(par), which is observed for depolarization ratios <40% mainly at low cloud altitudes, can be alternatively explained by horizontal alignment of a fraction of the cirrus particle population. C1 NASA, Goddard Space Flight Ctr, Atmospheres Lab, Atmospher Chem & Dynam Branch, Greenbelt, MD 20771 USA. Univ Maryland Baltimore Cty, Joint Ctr Earth Syst Technol, College Pk, MD USA. DLR German Aerosp Ctr, Remote Sensing Technol Inst, D-82234 Wessling, Germany. RP Reichardt, J (reprint author), NASA, Goddard Space Flight Ctr, Atmospheres Lab, Atmospher Chem & Dynam Branch, Greenbelt, MD 20771 USA. EM reichardt@code916.gsfc.nasa.gov; sreichardt@aeolus.gsfc.nasa.gov; michael.hess@dlr.de; mcgee@aeolus.gsfc.nasa.gov RI McGee, Thomas/G-4951-2013 NR 52 TC 24 Z9 25 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 NOV PY 2002 VL 107 IS D21 AR 4562 DI 10.1029/2002JD002589 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 643KK UT WOS:000180860300014 ER PT J AU Rinsland, CP Goldman, A Mahieu, E Zander, R Notholt, J Jones, NB Griffith, DWT Stephen, TM Chiou, LS AF Rinsland, CP Goldman, A Mahieu, E Zander, R Notholt, J Jones, NB Griffith, DWT Stephen, TM Chiou, LS TI Ground-based infrared spectroscopic measurements of carbonyl sulfide: Free tropospheric trends from a 24-year time series of solar absorption measurements SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE long-term trends; carbonyl sulfide; infrared spectroscopy; troposphere; remote sensing ID RESOLUTION BALLOON-BORNE; STRATOSPHERIC AEROSOLS; SOUTHERN-HEMISPHERE; NU(1)+NU(3) BANDS; COLUMN ABUNDANCES; ATMOSPHERIC OCS; GLOBAL SOURCES; ERROR ANALYSIS; FTIR SPECTRA; KITT PEAK AB [1] Solar absorption spectra recorded over a 24-year time span have been analyzed to retrieve average free tropospheric mixing ratios of carbonyl sulfide (OCS). The measurements were recorded with the Fourier transform spectrometer located in the U. S. National Solar Observatory McMath solar telescope facility on Kitt Peak (altitude 2.09 km, lat. 31.9degreesN, long. 111.6degreesW), southwest of Tucson, Arizona, and were obtained on 167 days between May 1978 and February 2002, typically at 0.01-cm(-1) spectral resolution. A best fit to the time series shows an average mixing ratio of 566 pptv (1 pptv = 10(-12) per unit volume) between 2.09 and 10 km, a small but statistically significant long-term decrease equal to (-0.25 +/- 0.04)% yr(-1), 1 sigma, and a seasonal variation with a summer maximum, a winter minimum, and a peak amplitude of (1.3 +/- 0.4)%, 1 sigma, relative to the mean. Although a statistically significant decline and seasonal variation have been detected, both are exceedingly small. The present results confirm and extend earlier studies showing that the OCS free tropospheric abundance at northern midlatitudes has remained nearly constant over the last decades. C1 NASA, Langley Res Ctr, Div Atmospher Sci, Hampton, VA 23681 USA. Univ Denver, Dept Phys, Denver, CO 80208 USA. Univ Liege, Inst Astrophys & Geophys, B-4000 Liege, Belgium. Univ Bremen, Inst Environm Phys, D-28334 Bremen, Germany. Univ Wollongong, Dept Chem, Wollongong, NSW 2522, Australia. Wyle Labs, Hampton, VA 23666 USA. RP Rinsland, CP (reprint author), NASA, Langley Res Ctr, Div Atmospher Sci, 21 Langley Blvd,Mail Stop 401A, Hampton, VA 23681 USA. EM c.p.rinsland@larc.nasa.gov; goldman@acd.ucar.edu; Emmanuel.Mahieu@ulg.ac.be; R.Zander@ulg.ac.be; jnotholt@iup.physik.uni-bremen.de; njones@uow.edu.au; David_Griffith@uow.edu.au; tstephen@du.edu; l.s.chiou@larc.nasa.gov RI Notholt, Justus/P-4520-2016; OI Notholt, Justus/0000-0002-3324-885X; Mahieu, Emmanuel/0000-0002-5251-0286 NR 66 TC 16 Z9 16 U1 1 U2 9 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD NOV PY 2002 VL 107 IS D22 AR 4657 DI 10.1029/2002JD002522 PG 9 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 643NN UT WOS:000180867500057 ER PT J AU Treuhaft, RN Asner, GP Law, BE Van Tuyl, S AF Treuhaft, RN Asner, GP Law, BE Van Tuyl, S TI Forest leaf area density profiles from the quantitative fusion of radar and hyperspectral data SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE vegetation profiling; leaf area density; interferometric radar; hyperspectral imaging spectroscopy ID SAR INTERFEROMETRY; RADIATIVE-TRANSFER; DISCONTINUOUS CANOPIES; SEASONAL-VARIATION; ASYMMETRIC CROWNS; PONDEROSA PINE; FOLIAGE AREA; WATER-VAPOR; AVIRIS DATA; VEGETATION AB [1] The leaf area density (LAD) of a forest is an important indicator of forest biomass and is therefore pertinent to monitoring carbon sequestration and change. Quantitative physical models were used to estimate forest LAD from radar and hyperspectral airborne remote sensing observations. A parameter-estimation technique based on physical models minimizes the need for in situ observations and thereby facilitates global remote sensing of forest structure. Using data from the NASA Airborne Synthetic Aperture Radar (AIRSAR) and the NASA Airborne Visible and Infrared Imaging Spectrometer (AVIRIS) over three forest plots in Central Oregon, parameters were estimated separately from the radar and hyperspectral data and then combined to form LAD. Gaussian relative LAD profiles were estimated from multialtitude interferometric and polarimetric AIRSAR data. Leaf area indices (LAI) were estimated from AVIRIS data and used to normalize the relative density profiles to produce LAD as a function of height. LAD was also determined from field measurements of geometric tree properties and LAI. LADs in the three forest plots were in the 0.02-0.18 m(2) m(-3) range, with LAIs in the range 0.8-2.4 m(2) m(-2). The agreement between the remotely sensed and field-measured LAD was typically 0.02 m(2) m(-3) but occasionally as high as 0.06 m(2) m(-3), which was within a 1-2 standard error range. More complex models for the remotely sensed relative density, along with more diverse radar observation strategies, will improve LAD accuracy in the future. LAD estimation will also improve when radar, hyperspectral, and other relevant remote sensing data sets are combined in a single parameter-estimation process, as opposed to the separate estimations performed in this first LAD demonstration. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Carnegie Inst, Dept Global Ecol, Stanford, CA 94305 USA. Oregon State Univ, Coll Forestry, Corvallis, OR 97331 USA. RP Treuhaft, RN (reprint author), CALTECH, Jet Prop Lab, 138-212,4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM rnt@radar-sci.jpl.nasa.gov RI Asner, Gregory/G-9268-2013; Van Tuyl, Steven/E-2814-2014; OI Asner, Gregory/0000-0001-7893-6421; Van Tuyl, Steven/0000-0002-8752-272X; Law, Beverly/0000-0002-1605-1203 NR 48 TC 27 Z9 31 U1 0 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 NOV PY 2002 VL 107 IS D21 AR 4568 DI 10.1029/2001JD000646 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 643KK UT WOS:000180860300020 ER PT J AU Twohy, CH Clement, CF Gandrud, BW Weinheimer, AJ Campos, TL Baumgardner, D Brune, WH Faloona, I Sachse, GW Vay, SA Tan, D AF Twohy, CH Clement, CF Gandrud, BW Weinheimer, AJ Campos, TL Baumgardner, D Brune, WH Faloona, I Sachse, GW Vay, SA Tan, D TI Deep convection as a source of new particles in the midlatitude upper troposphere SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE particles; aerosols; sulfuric acid; nucleation; cirrus clouds; convection ID MARINE BOUNDARY-LAYER; CONDENSATION NUCLEUS COUNTER; ATMOSPHERIC NUCLEI; AEROSOL-PARTICLES; SIZE DISTRIBUTION; CUMULUS CLOUDS; HOMOGENEOUS NUCLEATION; OPTICAL-PROPERTIES; EMISSION INDEXES; DIMETHYL SULFIDE AB [1] A case study of new particle formation in the region downwind of a mesoscale convective system stretching across much of the central United States is presented. Airborne measurements were made of condensation nuclei (CN), cloud particle surface area, water vapor, and other gases. CN concentrations were greatly enhanced above and downwind of the cirrus anvil, with maximum concentrations of 45,000 per standard cm(3). Volatility and electron microscope measurements indicated that most of the particles were likely to be small sulfate particles. The enhancement extended over at least a 600-km region. Multivariate statistical analysis revealed that high CN concentrations were associated with surface tracers, as well as convective elements. Convection apparently brings gas-phase particle precursors from the surface to the storm outflow region, where particle nucleation is favored by the extremely low temperatures. Simple calculations showed that deep convective systems may contribute to a substantial portion of the background aerosol in the upper troposphere at midlatitudes. C1 Oregon State Univ, Coll Oceanog, Corvallis, OR 97331 USA. Natl Ctr Atmospher Res, Boulder, CO 80303 USA. Univ Nacl Autonoma Mexico, Ctr Ciencias Atmosfera, Mexico City 04510, DF, Mexico. Penn State Univ, Dept Meteorol, University Pk, PA 16802 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. Georgia Inst Technol, Sch Earth & Atmospher Sci, Atlanta, GA 30332 USA. RP Twohy, CH (reprint author), Oregon State Univ, Coll Oceanog, Oceanog Adm Bldg 104, Corvallis, OR 97331 USA. EM twohy@coas.oregonstate.edu; Charles.F.Clement@btinternet.com; gandrud@particlemetrics.com; wein@ucar.edu; campos.@ncar.ucar.edu; darrel@servidor.unam.mx; brune@essc.psu.edu; faloona@ucar.edu; g.w.sachse@larc.nasa.gov; s.a.vay@larc.nasa.gov; dtan@eas.gatech.edu NR 57 TC 48 Z9 49 U1 1 U2 5 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD NOV PY 2002 VL 107 IS D21 AR 4560 DI 10.1029/2001JD000323 PG 10 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 643KK UT WOS:000180860300012 ER PT J AU Desai, SD AF Desai, SD TI Observing the pole tide with satellite altimetry SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article DE tide; pole tide; satellite altimetry; TOPEX/Poseidon; Love number; Chandler wobble ID CHANDLER-WOBBLE; EARTHS ROTATION; NORTH-SEA; PERIOD; OCEAN; DEFORMATION; EXCITATION; MOTION; MODEL AB [1] Almost 9 years of sea surface height observations from the TOPEX/Poseidon (T/P) satellite altimetry mission are used to observe the geocentric pole tide deformations of the sea surface. If the oceans are assumed to have an equilibrium response, then satellite altimeters effectively observe the equipotential surface that is associated with the solid Earth and ocean pole tide deformations. The long-wavelength component of the geocentric pole tide deformations at the Chandler wobble period is observed from T/P altimetry to be consistent with the theoretical self-consistent equilibrium response of the ocean pole tide. The geocentric pole tide explains 70% of the variance in the degree 2 order 1 spherical harmonic component of the residual sea surface heights that are observed by T/P, after removing the seasonal, inverse barometer, and lunisolar tidal effects. If the long-wavelength component of the ocean pole tide is assumed to have an equilibrium response at the Chandler wobble period, then satellite altimetry proves to be another geodetic technique that can be used to estimate the Love number k(2) at that period. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91101 USA. RP Desai, SD (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,M-S 238-600, Pasadena, CA 91101 USA. NR 31 TC 77 Z9 78 U1 3 U2 12 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 NOV PY 2002 VL 107 IS C11 AR 3186 DI 10.1029/2001JC001224 PG 13 WC Oceanography SC Oceanography GA 638KP UT WOS:000180570400007 ER PT J AU Bandfield, JL Edgett, KS Christensen, PR AF Bandfield, JL Edgett, KS Christensen, PR TI Spectroscopic study of the Moses Lake dune field, Washington: Determination of compositional distributions and source lithologies SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article DE infrared spectroscopy; factor analysis; outflow channels; sediment transport ID THERMAL EMISSION-SPECTROSCOPY; PATHFINDER LANDING SITE; MARTIAN SURFACE; INFRARED IMAGES; AEOLIAN DUNES; DEATH-VALLEY; CALIFORNIA; MINERALS; MARS; SEDIMENTS AB [1] Source lithologies and transport histories of materials within the Ephrata Fan are investigated. Data were collected using a variety of remote-sensing, laboratory spectroscopic, and field observations and techniques. Laboratory thermal emission spectra were collected of bedrock within the Grand Coulee, dune samples, and clast deposits. Factor analysis, target transformation, and end-member recovery techniques were applied to the set of dune samples as well as a set of grain size fractions. The dune sample spectra are composed of three components that represent basalt, granodiorite, and clay compositions. The basalt and granodiorite components are similar to spectra of clast and bedrock samples from the Grand Coulee and the Ephrata Fan. The clay component is similar to weathering surfaces located within the dune field. The same components were recovered from the set of grain size fractions from a single dune sample demonstrating a relatively higher basalt concentration with grain sizes greater than similar to250 mum. Thermal Infrared Multispectral Scanner (TIMS) data display significant intradune compositional variation and no discernable interdune compositional variation, indicating that the basalt and granodiorite components were likely deposited simultaneously and subsequently separated by wind based on grain size. Basalt and granodiorite bedrock units within the Channeled Scablands are source materials for the deposits within the Ephrata Fan and Moses Lake dune field. The Columbia River, located 20 km west of the dune field, is not a likely source of material. C1 NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. Arizona State Univ, Dept Geol, Tempe, AZ 85287 USA. Malin Space Sci Syst, San Diego, CA 92191 USA. RP Bandfield, JL (reprint author), NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Code 693-0, Greenbelt, MD 20771 USA. NR 46 TC 23 Z9 23 U1 0 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD NOV PY 2002 VL 107 IS E11 AR 5092 DI 10.1029/2000JE001469 PG 15 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 639RQ UT WOS:000180643400002 ER PT J AU Bishop, JL Murchie, SL Pieters, CM Zent, AP AF Bishop, JL Murchie, SL Pieters, CM Zent, AP TI A model for formation of dust, soil, and rock coatings on Mars: Physical and chemical processes on the Martian surface SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Review DE Mars; spectroscopy; chemical alteration; aeolian processes; cemented soil; rock coatings ID THERMAL EMISSION SPECTROMETER; PATHFINDER LANDING SITE; VIKING LANDER-2 SITE; WATER CYCLE; REFLECTANCE SPECTROSCOPY; SEASONAL RESERVOIRS; MAGNETIC-PROPERTIES; IRON-OXIDES; ATMOSPHERE; HEMATITE AB [1] A model is presented here to explain the generation of surface material on Mars using chemical, magnetic, and spectroscopic data from Mars and geologic analogs from terrestrial sites. One basic premise is that the dust/soil units are not derived exclusively from local rocks, but are rather a product of global, and possibly remote, weathering processes. Another assumption in this model is that there are both physical and chemical interactions of the atmosphere with dust particles and that these two processes create distinctly different products. Physical processes distribute dust particles on rocks and drift units, forming physically aggregated layers; these are reversible processes. Chemical reactions of the dust/soil particles create alteration rinds on rock surfaces and cohesive, crusted surface units between rocks, both of which are relatively permanent materials. According to this model the dominant components of the dust/soil particles are derived from alteration of volcanic ash and tephra and contain primarily nanophase and poorly crystalline ferric oxide/oxyhydroxide phases as well as silicates. These phases are the alteration products that formed in a low-moisture environment. These dust/soil particles also contain a smaller amount of material that was exposed to more water and contains crystalline ferric oxides/oxyhydroxides, sulfates, and clay silicates. These components could have formed through hydrothermal alteration at steam vents or fumeroles, thermal fluids, or through evaporite deposits. Wet/dry cycling experiments are presented here on Mars soil analogue mixtures containing poorly crystalline and crystalline components dominated by nanophase to similar to2 mum diameter particles. Cemented products of these soil mixtures are formed in these experiments, and variation in the surface texture was observed for samples containing smectites, nonhydrated silicates, or sulfates. Reflectance spectra were measured of the initial particulate mixtures, the cemented products, and ground versions of the cemented material. The spectral contrast in the visible/near-infrared and midinfrared regions is significantly reduced for the cemented material compared to the initial soil and somewhat reduced for the ground, cemented soil compared to the initial soil. The results of this study suggest that transient fluvial activity on Mars will have a profound effect on the texture and spectral properties of the dust/soil particles on the surface. The model developed in this study provides an explanation for the generation of cemented or crusted soil units and rock coatings on Mars and may explain albedo variations on the surface observed near large rocks or crater rims. C1 NASA, Ames Res Ctr, SETI Inst, Moffett Field, CA 94035 USA. Johns Hopkins Univ, Appl Phys Lab, Laurel, MD 20723 USA. Brown Univ, Dept Geol Sci, Providence, RI 02912 USA. RP NASA, Ames Res Ctr, SETI Inst, MS-239-4, Moffett Field, CA 94035 USA. EM jbishop@mail.arc.nasa.gov RI Murchie, Scott/E-8030-2015 OI Murchie, Scott/0000-0002-1616-8751 NR 137 TC 37 Z9 37 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9097 EI 2169-9100 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD NOV PY 2002 VL 107 IS E11 AR 5097 DI 10.1029/2001JE001581 PG 17 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 639RQ UT WOS:000180643400007 ER PT J AU Borucki, JG Khare, B Cruikshank, DP AF Borucki, JG Khare, B Cruikshank, DP TI A new energy source for organic synthesis in Europa's surface ice SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article DE organic synthesis; energy source; meteorite impacts; ice; Europa ID CRACKS AB [1] Colored regions on Jupiter's satellite Europa and other icy bodies in the outer solar system may be contaminated by organic macromolecular solid material that is produced when surface ices are exposed to electrical energy. Hypervelocity meteorite impacts and fracture may release tidal and tectonic stresses in icy crusts in the form of electrical discharges, which provide the energy for in situ synthesis of the organic solids. We report for the first time here on measurements of electrical discharge, light emission, and magnetic phenomena in hypervelocity impacts into ice with small iron projectiles having velocities similar to5 km s(-1). In these experiments, part of the impacting projectile's kinetic energy is converted into electrical potential, while the mechanical disruption of the impact also causes the release of stress energy as light, heat, and electrical and magnetic fields as secondary emissions. These new energy sources described here suggest that the dark material in the area of impact craters may be solid phase, complex organic material called tholin, generated from the energy of the impacts. The morphology of Europa's impact craters is suggestive of fluidized colored material welling up from the fracture zone, probably during crater formation, but possibly later. Large pools of liquid water might persist under the meteorite crater for thousands of years [Thomson and Sagan, 1992], with the potential for prebiotic chemistry to take place at an accelerated rate due to energy pumped in from the secondary emissions. C1 NASA, Ames Res Ctr, SETI Inst, Moffett Field, CA 94035 USA. RP NASA, Ames Res Ctr, SETI Inst, Mail Stop 239-4, Moffett Field, CA 94035 USA. EM jborucki@mail.arc.nasa.gov NR 19 TC 5 Z9 6 U1 0 U2 11 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9097 EI 2169-9100 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD NOV PY 2002 VL 107 IS E11 AR 5114 DI 10.1029/2002JE001841 PG 5 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 639RQ UT WOS:000180643400026 ER PT J AU Delitsky, ML Lane, AL AF Delitsky, ML Lane, AL TI Saturn's inner satellites: Ice chemistry and magnetosphere effects SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Review DE Saturnian satellites; planetary chemistry; Saturn magnetosphere; organic chemistry; Saturn; nitrogen oxides chemistry ID KINETIC DATA-BASE; KRONIAN MAGNETOSPHERE; GALILEAN SATELLITES; RATE COEFFICIENT; PROPELLANT COMBUSTION; PLASMA OBSERVATIONS; OXIDE CHEMISTRY; ABSORPTION-BAND; THERMAL PLASMA; PHOTODISSOCIATION AB [1] The magnetosphere of Saturn contains plasma ions that corotate with the magnetic field of the planet and impact the satellites, changing the chemical nature of their surfaces. The Voyager spacecraft observed ionic species such as O+,H2O+,N+,N-2(+),H+, and others, as well as electrons. If N+ and N-2(+) ions from Titan reach the inner satellites Rhea, Dione, Tethys, Enceladus, and Mimas, implanting of these ions into their water-ice surfaces should induce a complex nitrogen oxides chemistry. Species observed in laboratory experiments of N+ impact into water ice include NO, N2O, NO2,NO3, HNO2, HNO3,NH2OH, HNO, NH, and NH2. Impact of N-2(+) may yield N2O, HNNO, and N-2. If the surfaces also contain CO2, then other species produced as a result of N+ impact into H2O/ CO2 ice may be HNCO, NCO, and R-OCN. Once HNCO (with its C-N bond) is formed, then production of amino acids may occur. Chemical schemes show that successive reaction of HNCO with H and CO could lead to the smallest amino acid, glycine, in only five steps. Energy fluxes for ions, electrons, and photons are summed for each satellite. Column densities of the nitrogen-containing species are calculated. The simplest molecule, NO, should have an appreciable vapor pressure at Saturnian satellite temperatures. At 90 K, the vapor pressure of NO is similar to4 mbar. At 105 K, its vapor pressure is 98 mbar. These gases may form transient atmospheres on the satellites. This should be observable with high-resolution instruments. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Delitsky, ML (reprint author), CALTECH, Jet Prop Lab, Mail Stop 169-237,4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 125 TC 23 Z9 23 U1 3 U2 9 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD NOV PY 2002 VL 107 IS E11 AR 5093 DI 10.1029/2002JE001855 PG 17 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 639RQ UT WOS:000180643400003 ER PT J AU Dello Russo, N Mumma, MJ DiSanti, MA Magee-Sauer, K AF Dello Russo, N Mumma, MJ DiSanti, MA Magee-Sauer, K TI Production of ethane and water in comet C/1996 B2 Hyakutake SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article DE comets; infrared; spectroscopy; water; ethane; Hyakutake ID O1 HALE-BOPP; EMISSION FEATURE; CARBON-MONOXIDE; MU-M; INFRARED-SPECTROSCOPY; METHANOL; SPECTRUM; HALLEY; MODEL; 21P/GIACOBINI-ZINNER AB [1] Ethane (C2H6) and water (H2O) were detected in Comet C/1996 B2 Hyakutake between UT 1996 March 23.4 (R-h = 1. 08 AU preperihelion) and 1996 April 12.2 (R-h = 0.64 AU preperihelion). Our long-slit infrared spectra featured both high spectral dispersion and high spatial resolution about the nucleus, permitting the extraction of rotational temperatures, production rates, and spatial distributions of species along the slit. Production rates were measured for water (on four dates) and ethane (on three dates). Their average relative abundance was C2H6 /H2O = (6.2 +/- 0.7) 10(-3). The spatial distributions of C2H6 and H2O molecules in the coma were consistent with both species being released directly from the nucleus on all dates, although asymmetries about the nucleus are seen for both gas and dust. C1 Catholic Univ Amer, Dept Phys, Washington, DC 20064 USA. Rowan Univ, Dept Chem & Phys, Glassboro, NJ 08028 USA. NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. RP Catholic Univ Amer, Dept Phys, Washington, DC 20064 USA. EM ysndr@lepvax.gsfc.nasa.gov RI mumma, michael/I-2764-2013; Magee-Sauer, Karen/K-6061-2015; Dello Russo, Neil/G-2727-2015 OI Magee-Sauer, Karen/0000-0002-4979-9875; Dello Russo, Neil/0000-0002-8379-7304 NR 46 TC 22 Z9 22 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9097 EI 2169-9100 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD NOV PY 2002 VL 107 IS E11 AR 5095 DI 10.1029/2001JE001838 PG 11 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 639RQ UT WOS:000180643400005 ER PT J AU Forbes, JM Bridger, AFC Bougher, SW Hagan, ME Hollingsworth, JL Keating, GM Murphy, J AF Forbes, JM Bridger, AFC Bougher, SW Hagan, ME Hollingsworth, JL Keating, GM Murphy, J TI Nonmigrating tides in the thermosphere of Mars SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article DE Mars; thermosphere; density; nonmigrating tides ID GENERAL-CIRCULATION MODEL; SOLAR-CYCLE VARIATION; MARTIAN ATMOSPHERE; GLOBAL SURVEYOR; KELVIN WAVE; THERMAL TIDES; SOUTH-POLE; SIMULATIONS; WINDS; ACCELEROMETER AB [1] The vertical propagation of nonmigrating (i.e., longitude-dependent or non-Sun-synchronous) solar diurnal and semidiurnal tides into the thermosphere of Mars is investigated through numerical simulation. The waves are generated in the NASA Ames Mars general circulation model (MGCM) through solar radiative, topographic, and nonlinear processes using a comprehensive physics package and including a diurnal cycle. At an altitude near 70 km, zonal wave number decompositions of the diurnal and semidiurnal tidal fields are performed, and each wave component is extended from 70 to 250 km using a linear steady state global scale wave model for Mars (Mars GSWM). Conditions representative of aerocentric longitudes L-s = 30 (near equinox) and L-s = 270 (Southern Hemisphere summer solstice) are considered. Modeled total relative density variations of order +/-10-40% near 125 km are analyzed in terms of the zonal wave numbers (k(s)) seen from the Sun-synchronous perspective of the Mars Global Surveyor (MGS) accelerometer experiment, and yield reasonable agreement in amplitude and phase with the density measurements. The model indicates the two most important waves responsible for k(s) = 3 to be the eastward-propagating diurnal and semidiurnal oscillations with zonal wave numbers s = 2 (similar to15-40%) and s = 1 (similar to8%), respectively. The eastward-propagating diurnal component with s = 1 (similar to15%) and the semidiurnal standing (s = 0) oscillation (similar to4-23%) are concluded to be the main contributors to the k(s) = 2 longitudinal density variation seen from the Mars Global Surveyor (MGS). The standing (s = 0) diurnal oscillation (similar to4-5%) and the westward-propagating semidiurnal component with s = 1 (similar to5-8%) emerge as the most likely contributors to k(s) = 1. Other waves that may make important secondary contributions include the westward-propagating semidiurnal oscillations with s = 3 (similar to4-6%) and s = 4 (similar to3-9%). In addition, above 100 km the wind and temperature fields associated with the above waves represent similar to15-30% perturbations on the Sun-synchronous wind and temperature fields driven in situ by EUV and near-IR solar radiation absorption. Nonmigrating tides primarily arise from zonal asymmetries in wave forcing associated with Mars' topography; our results show for the first time that the dynamical effects of Mars' topography extend throughout the atmospheric column to Mars' exobase (similar to200-250 km). C1 Univ Colorado, Dept Aerosp Engn, Boulder, CO 80309 USA. San Jose State Univ, Dept Meteorol, San Jose, CA 95192 USA. Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. Natl Ctr Atmospher Res, High Altitude Observ, Boulder, CO 80307 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. George Washington Univ, NASA, Langley Res Ctr, Hampton, VA 23606 USA. New Mexico State Univ, Dept Astron, Las Cruces, NM 88003 USA. RP Forbes, JM (reprint author), Univ Colorado, Dept Aerosp Engn, Boulder, CO 80309 USA. RI Hagan, Maura/C-7200-2008; Bougher, Stephen/C-1913-2013 OI Hagan, Maura/0000-0002-8866-7429; Bougher, Stephen/0000-0002-4178-2729 NR 37 TC 50 Z9 51 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-PLANET JI J. Geophys. Res.-Planets PD NOV PY 2002 VL 107 IS E11 AR 5113 DI 10.1029/2001JE001582 PG 12 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 639RQ UT WOS:000180643400025 ER PT J AU Jolliff, B Knoll, A Morris, RV Moersch, J McSween, H Gilmore, M Arvidson, R Greeley, R Herkenhoff, K Squyres, S AF Jolliff, B Knoll, A Morris, RV Moersch, J McSween, H Gilmore, M Arvidson, R Greeley, R Herkenhoff, K Squyres, S TI Remotely sensed geology from lander-based to orbital perspectives: Results of FIDO rover May 2000 field tests SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article DE FIDO; Mars rover; rover field test; remote sensing; robotic ID LANDING SITE; CALIFORNIA; MISSION; LAKE AB [1] Blind field tests of the Field Integration Design and Operations (FIDO) prototype Mars rover were carried out 7-16 May 2000. A Core Operations Team (COT), sequestered at the Jet Propulsion Laboratory without knowledge of test site location, prepared command sequences and interpreted data acquired by the rover. Instrument sensors included a stereo panoramic camera, navigational and hazard-avoidance cameras, a color microscopic imager, an infrared point spectrometer, and a rock coring drill. The COT designed command sequences, which were relayed by satellite uplink to the rover, and evaluated instrument data. Using aerial photos and Airborne Visible and Infrared Imaging Spectrometer (AVIRIS) data, and information from the rover sensors, the COT inferred the geology of the landing site during the 18 sol mission, including lithologic diversity, stratigraphic relationships, environments of deposition, and weathering characteristics. Prominent lithologic units were interpreted to be dolomite-bearing rocks, kaolinite-bearing altered felsic volcanic materials, and basalt. The color panoramic camera revealed sedimentary layering and rock textures, and geologic relationships seen in rock exposures. The infrared point spectrometer permitted identification of prominent carbonate and kaolinite spectral features and permitted correlations to outcrops that could not be reached by the rover. The color microscopic imager revealed fine-scale rock textures, soil components, and results of coring experiments. Test results show that close-up interrogation of rocks is essential to investigations of geologic environments and that observations must include scales ranging from individual boulders and outcrops (microscopic, macroscopic) to orbital remote sensing, with sufficient intermediate steps (descent images) to connect in situ and remote observations. C1 Washington Univ, Dept Earth & Planetary Sci, St Louis, MO 63130 USA. Harvard Univ, Bot Museum, Cambridge, MA 02138 USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. Univ Tennessee, Dept Geol Sci, Knoxville, TN 37996 USA. CALTECH, Jet Prop Lab, Pasadena, CA USA. Arizona State Univ, Dept Geol, Tempe, AZ 85287 USA. US Geol Survey, Flagstaff, AZ 86001 USA. Cornell Univ, Ctr Radiophys & Space Res, Ithaca, NY 14853 USA. RP Washington Univ, Dept Earth & Planetary Sci, Campus Box 1169, St Louis, MO 63130 USA. EM blj@levee.wustl.edu RI Moersch, Jeffrey/F-7189-2010; Gilmore, Martha/G-5856-2011 NR 26 TC 3 Z9 3 U1 0 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9097 EI 2169-9100 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD NOV PY 2002 VL 107 IS E11 AR 8008 DI 10.1029/2000JE001470 PG 17 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 639RQ UT WOS:000180643400021 ER PT J AU Magee-Sauer, K Mumma, MJ DiSanti, MA Dello Russo, N AF Magee-Sauer, K Mumma, MJ DiSanti, MA Dello Russo, N TI Hydrogen cyanide in comet C/1996 B2 Hyakutake SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article DE comets; infrared; spectroscopy; HCN; Hyakutake; hydrogen cyanide ID O1 HALE-BOPP; SENSITIVE UPPER LIMIT; CARBON-MONOXIDE; AUSTIN 1989C1; EMISSION; HCN; WATER; IDENTIFICATION; SPECTROSCOPY; PERIHELION AB [1] Spectral emission from HCN in C/1996 B2 Hyakutake was detected on UT 1996 March 24.4 (r(h) = 1.06 AU, Delta = 0.106 AU), using the CSHELL infrared spectrometer at the NASA Infrared Telescope Facility. A Boltzmann analysis of eight ro-vibrational lines in the nu(3) band returned a rotational temperature (83 +/- 9 K) for a region centered on the nucleus. The global HCN production rate was (4.50 +/- 0.81) 10(26) molecules s(-1). The HCN abundance relative to water is then (0.18 +/- 0.04)%, based on direct measurements of H2O made on the same night with the same instrument and reduced with the same data processing algorithms. The measured spatial distribution for HCN is consistent with its release at the nucleus; no significant contribution from a distributed source is required within similar to600 km of the nucleus. We use these data to obtain insights regarding the origin of HCN in this comet. C1 Rowan Univ, Dept Chem & Phys, Glassboro, NJ 08028 USA. Catholic Univ Amer, Dept Phys, Washington, DC 20064 USA. NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. RP Magee-Sauer, K (reprint author), Rowan Univ, Dept Chem & Phys, Glassboro, NJ 08028 USA. RI mumma, michael/I-2764-2013; Magee-Sauer, Karen/K-6061-2015; Dello Russo, Neil/G-2727-2015 OI Magee-Sauer, Karen/0000-0002-4979-9875; Dello Russo, Neil/0000-0002-8379-7304 NR 47 TC 16 Z9 16 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD NOV PY 2002 VL 107 IS E11 AR 5096 DI 10.1029/2002JE001863 PG 10 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 639RQ UT WOS:000180643400006 ER PT J AU Moersch, JE Jolliff, B McSween, HY Morris, RV Gilmore, MS Arvidson, RE Squyres, SW AF Moersch, JE Jolliff, B McSween, HY Morris, RV Gilmore, MS Arvidson, RE Squyres, SW TI Synthesis of overhead and ground-based infrared spectroscopy at the 2000 FIDO Mars rover field test SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article DE Mars missions; FIDO rover; infrared remote sensing; AVIRIS; field spectrometer AB [1] In the May 2000 Field Integrated Design and Operations (FIDO) Mars Rover Field Test, an off-site science team was charged with the goal of characterizing the geology of a previously unknown field location by commanding and collecting observations from a robotic rover, similar to those planned for future Mars missions. One unique feature of this test was the degree to which the science team was able to make use of previously acquired overhead remote-sensing data together with ground-based observations by the rover. In particular, an Airborne Visible/ Infrared Imaging Spectrometer scene covering the region of the field test was used in concert with observations from the rover's near-infrared point spectrometer to develop a coherent and essentially correct geologic story for the test site. Using the overhead data, the science team was able to form hypotheses that were testable using rover observations on the ground. The team was able to establish the provenance of exotic samples within reach of the rover by making a spectroscopic link to units observed from above. The science team was also able to "extend'' the spectral range of the rover's onboard spectrometer via inferred connections to units mapped from above with greater spectral range. The net result of the success of this rover trial is an increase in experience and confidence for NASA's Mars mission strategy, which features strong ties between early orbital reconnaissance missions for geologic mapping and subsequent rover missions to the surface. C1 Univ Tennessee, Dept Geol Sci, Knoxville, TN 37996 USA. Washington Univ, Dept Earth & Planetary Sci, St Louis, MO 63130 USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Cornell Univ, Ithaca, NY 14853 USA. RP Moersch, JE (reprint author), Univ Tennessee, Dept Geol Sci, 306 GS Bldg, Knoxville, TN 37996 USA. RI Moersch, Jeffrey/F-7189-2010; Gilmore, Martha/G-5856-2011 NR 19 TC 2 Z9 2 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD NOV PY 2002 VL 107 IS E11 AR 8007 DI 10.1029/2001JE001524 PG 10 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 639RQ UT WOS:000180643400013 ER PT J AU Molina-Cuberos, GJ Schwingenschuh, K Lopez-Moreno, JJ Rodrigo, R Lara, LM Anicich, V AF Molina-Cuberos, GJ Schwingenschuh, K Lopez-Moreno, JJ Rodrigo, R Lara, LM Anicich, V TI Nitriles produced by ion chemistry in the lower ionosphere of Titan SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article DE Titan; atmosphere; chemistry; ionosphere ID VOYAGER INFRARED OBSERVATIONS; CLUSTERING REACTIONS; DISSOCIATIVE RECOMBINATION; ORGANIC-MOLECULES; ATMOSPHERE; HCNH+; THERMOCHEMISTRY; CYANOACETYLENE; SIMULATION; IONIZATION AB [1] Titan, the largest satellite of Saturn, possesses a dense N-2-CH4 atmosphere rich in organics with a complex chemistry that could be similar to Earth's primordial atmosphere. Due to its massive atmosphere and the long distance to the Sun, cosmic rays are the main energetic source of the lower part of the atmosphere. Cosmic radiation can reach Titan's troposphere (z < 40 km) and activate the chemistry at depths where UV light and high-energy electrons cannot penetrate. The interaction of cosmic rays with the neutral constituents of Titan produces a complex ion chemistry that leads to the formation of a high variety of massive ions and organic molecules. The low temperatures and high pressures prevailing in Titan's atmosphere result in a high efficiency of three-body reactions and on the formation of ion clusters. Association of neutral molecules with HCNH+,CH3CNH+, and HC3NH+ produces ions containing the CN group, and the electron recombination of these clusters can produce a high variety of N-containing compounds. Here we propose schemes to synthesize nitrile-type molecules from the dissociative recombination ion clusters produced by cosmic rays. Our ion chemistry model can explain the existence of some of the nitriles found in laboratory studies, such as propenenitrile, propanenitrile, butanenitrile, pentanenitrile, and 10 more as well as predict the existence of new species. Experimental simulations of Titan's atmosphere yield the formation of a high number of species, which are not considered in the chemical schemes of current photochemical models. C1 Univ Murcia, Dept Fis, Grp Electromagnetismo Aplicado, E-30100 Murcia, Spain. CSIC, Inst Astrofis Andalucia, E-18080 Granada, Spain. CIT, Jet Prop Lab, Pasadena, CA USA. Inst Weltraumforsch OAW, A-8042 Graz, Austria. RP Molina-Cuberos, GJ (reprint author), Univ Murcia, Dept Fis, Grp Electromagnetismo Aplicado, Campus Espinardo, E-30100 Murcia, Spain. RI Molina-Cuberos, Gregorio /K-7522-2014; Lopez-Moreno, Jose Juan/C-7976-2011; OI Molina-Cuberos, Gregorio /0000-0002-5664-7028; Lopez-Moreno, Jose Juan/0000-0002-7946-2624 NR 40 TC 11 Z9 11 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD NOV PY 2002 VL 107 IS E11 AR 5099 DI 10.1029/2000JE001480 PG 11 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 639RQ UT WOS:000180643400009 ER PT J AU Smith, MD AF Smith, MD TI The annual cycle of water vapor on Mars as observed by the Thermal Emission Spectrometer SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article DE Mars; Mars atmosphere; water vapor; Mars Global Surveyor; Thermal Emission Spectrometer ID GLOBAL SURVEYOR; VERTICAL-DISTRIBUTION; MARTIAN ATMOSPHERE; TES OBSERVATIONS; SEASONAL CYCLE; DUST OPACITY; AEROBRAKING; PATHFINDER; PRESSURE; SPECTRA AB [1] Spectra taken by the Mars Global Surveyor Thermal Emission Spectrometer (TES) have been used to monitor the latitude, longitude, and seasonal dependence of water vapor for over one full Martian year (March 1999 to March 2001). A maximum in water vapor abundance is observed at high latitudes during midsummer in both hemispheres, reaching a maximum value of similar to100 pr-mum in the north and similar to50 pr-mum in the south. Low water vapor abundance (<5 pr-μm) is observed at middle and high latitudes in the fall and winter of both hemispheres. There are large differences in the hemispheric (north versus south) and seasonal (perihelion versus aphelion) behavior of water vapor. The latitudinal and seasonal dependence of the decay of the northern summer water vapor maximum implies cross-equatorial transport of water to the southern hemisphere, while there is little or no corresponding transport during the decay of the southern hemisphere summer maximum. The latitude-longitude dependence of annually averaged water vapor (corrected for topography) has a significant positive correlation with albedo and significant negative correlations with thermal inertia and surface pressure. Comparison of TES results with those retrieved from the Viking Orbiter Mars Atmospheric Water Detectors (MAWD) experiments [Jakosky and Farmer, 1982] shows some similar features but also many significant differences. The southern hemisphere maximum observed by TES was not observed by MAWD, and the large latitudinal gradient in annually averaged water vapor observed by MAWD does not appear in the TES results. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Smith, MD (reprint author), NASA, Goddard Space Flight Ctr, Code 693, Greenbelt, MD 20771 USA. RI Smith, Michael/C-8875-2012 NR 54 TC 148 Z9 150 U1 2 U2 13 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD NOV PY 2002 VL 107 IS E11 AR 5115 DI 10.1029/2001JE001522 PG 19 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 639RQ UT WOS:000180643400028 ER PT J AU Smrekar, SE Moreels, P Franklin, BJ AF Smrekar, SE Moreels, P Franklin, BJ TI Characterization and formation of polygonal fractures on Venus SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article DE Venus; thermal stresses; polygons; extensional fractures; climate change ID PLANETARY WRINKLE RIDGES; GLOBAL DISTRIBUTION; IMPACT CRATERS; LAVA FLOWS; CLIMATE; EVOLUTION; HISTORY; PLAINS; CLASSIFICATION; TECTONICS AB [1] Fracture theory predicts that polygonal cracks will form in the presence of an isotropic, extensional stress field. On Venus, polygonal fractures are observed on scales several orders of magnitude larger than on Earth, with an average diameter of 1.8 +/- 0.9 km. Proposed formation mechanisms include cooling following lava flow emplacement, lithospheric heating, and climate change. Here we examine the characteristics and geologic setting of 204 regions of polygons. Some regions display two spatially overlapping size ranges, with the larger spacing typically 10-25 km. Most polygonal fractures appear to be extensional, but some have the morphology of compressional ridges. Polygons are confined to plains regions and occur in association with shield fields (49%), coronae and coronae-like features (21.3%), tessera (17.5%), and wrinkle ridges (20%). In locations where polygons occur with shield fields, coronae, or both, they appear to have formed contemporaneously. Formation in conjunction with local heating events is consistent with the lithospheric cooling hypothesis. However, there is almost never the predicted decrease in size away from the center of coronae or shield fields. Only a small percentage of coronae and shield fields contain polygons, indicating that they are not typical of the formation process. The climate change-induced scenario is consistent with many characteristics of the polygons, including the small and large size ranges, the compressional ridges, and their occurrence with and without evidence of local heating. Although polygons may have diverse origins, including formation by multiple deformation events, overall polygon characteristics support the climate change hypothesis. C1 CALTECH, NASA Jet Prop Lab, Pasadena, CA 91109 USA. RP Smrekar, SE (reprint author), CALTECH, NASA Jet Prop Lab, MS 183-501,4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 40 TC 12 Z9 12 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD NOV PY 2002 VL 107 IS E11 AR 5098 DI 10.1029/2001JE001808 PG 18 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 639RQ UT WOS:000180643400008 ER PT J AU Stoker, CR Roush, TL Arvidson, RE Bresina, JL Bualat, MG Edwards, LJ Flueckiger, LJ Washington, RM Nguyen, LA Thomas, H Wright, AR AF Stoker, CR Roush, TL Arvidson, RE Bresina, JL Bualat, MG Edwards, LJ Flueckiger, LJ Washington, RM Nguyen, LA Thomas, H Wright, AR TI Two dogs, new tricks: A two-rover mission simulation using K9 and FIDO at Black Rock Summit, Nevada SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article DE Mars; rovers; robotics; virtual reality; visualization; field test ID ROVER FIELD EXPERIMENT; ATACAMA DESERT; DATA SETS; MARS; IDENTIFICATION; VISUALIZATION; CALIFORNIA; LAKE AB [1] An experiment illustrating two rovers cooperatively exploring a field site was performed at Black Rock Summit, Nevada, in May 2000. The rovers FIDO and K9 are mechanically identical prototype planetary rovers designed at the Jet Propulsion Laboratory. FIDO carried high-resolution false-color infrared and low-resolution monochrome stereo cameras and an infrared point spectrometer on a mast-mounted pointable platform, a manipulator arm equipped with a color microscopic imager, and a coring drill for sample collection. K9 carried on a mast-mounted pointable platform high-resolution color and low-resolution monochrome stereo cameras, and a Laser Induced Breakdown Spectrometer for standoff elemental analysis. A team located at Jet Propulsion Laboratory commanded the two rovers for 3 days. K9 obtained stereo images of targets, and three-dimensional models were constructed to determine the best locations for FIDO to obtain core samples. A drilling target was selected 1.5 m from the starting position of FIDO. Six command cycles and 2 m of traversing were required for FIDO to reach, drill into, and place an instrument on the target. K9 required 11 command cycles to traverse 60 m and obtain full-coverage stereo images of two rock targets along its route. Virtual reality-based visualization software called Viz provided situational awareness of the environment for both rovers. Commands to K9 were planned using Viz, resulting in improved rover performance. The results show that two rovers can be used synergistically to achieve science goals, but further testing is needed to completely explore the value of two-rover missions. C1 NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA. Washington Univ, Dept Earth & Planetary Sci, St Louis, MO 63130 USA. NASA, Ames Res Ctr, Computat Sci Div, Moffett Field, CA 94035 USA. RP NASA, Ames Res Ctr, Div Space Sci, Mail Stop 245-3, Moffett Field, CA 94035 USA. NR 41 TC 7 Z9 7 U1 1 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9097 EI 2169-9100 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD NOV PY 2002 VL 107 IS E11 AR 8009 DI 10.1029/2000JE001490 PG 13 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 639RQ UT WOS:000180643400027 ER PT J AU Turcotte, DL Shcherbakov, R Malamud, BD Kucinskas, AB AF Turcotte, DL Shcherbakov, R Malamud, BD Kucinskas, AB TI Is the Martian crust also the Martian elastic lithosphere? SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article DE Mars; gravity; areoid; lithosphere; compensation; crust ID MARS GLOBAL SURVEYOR; PHASE-TRANSITIONS; MANTLE CONVECTION; TOPOGRAPHY; THICKNESS; GRAVITY; INERTIA; TECTONICS; EVOLUTION; SUPPORT AB [1] Correlations between topography, gravity, and areoid on Mars are used to constrain the crustal and lithospheric thicknesses on the planet. Assuming that the Hellas basin is in isostatic equilibrium with Airy compensation, point correlations between areoid anomalies and topography are used to obtain the mean crustal density and the crustal thickness. We find that the crustal thickness at the reference zero elevation is 90 +/- 10 km. We also find that the mean crustal density is 2960 +/- 50 kg m(-3). We have also used several approaches to constrain the thickness of the elastic lithosphere. Using the spherical harmonic coefficients of the gravity potential and topography as a function of degrees, a relatively weak constraint on the globally averaged thickness of the elastic lithosphere is obtained. An improved constraint is obtained using wavelet transform analyses of great circle tracks of gravity and topography. The gravity-topography admittance as a function of wavelet wavelength constrains the globally averaged thickness of the elastic lithosphere to be in the range 90 n 10 km. The observation that the mean thicknesses of the crust and elastic lithosphere are likely to be equal suggests that a rheologically tougher crust is the elastic lithosphere. C1 Cornell Univ, Dept Earth & Atmospher Sci, Ithaca, NY 14853 USA. Kings Coll London, Dept Geog, London WC2R 2LS, England. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Cornell Univ, Dept Earth & Atmospher Sci, Snee Hall, Ithaca, NY 14853 USA. EM turcotte@geology.cornell.edu; roshch@geology.cornell.edu; bruce@malamud.com RI Shcherbakov, Robert/I-1036-2012; Malamud, Bruce/H-7885-2013 OI Shcherbakov, Robert/0000-0002-3057-0851; Malamud, Bruce/0000-0001-8164-4825 NR 59 TC 45 Z9 49 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9097 EI 2169-9100 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD NOV PY 2002 VL 107 IS E11 AR 5091 DI 10.1029/2001JE001594 PG 20 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 639RQ UT WOS:000180643400001 ER PT J AU Joughin, I Tulaczyk, S Bindschadler, R Price, SF AF Joughin, I Tulaczyk, S Bindschadler, R Price, SF TI Changes in west Antarctic ice stream velocities: Observation and analysis SO JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH LA English DT Article DE ice streams; ice sheets; Synthetic aperture Radar Interferometry (InSAR); glaciology; Antarctica ID RADAR INTERFEROMETRY; MASS-BALANCE; SUBGLACIAL GEOLOGY; MARGIN MIGRATION; BASAL MECHANICS; LATERAL DRAG; SHEET SYSTEM; FLOW; ELEVATION; MODEL AB [1] We have produced a map of velocity covering much of the Siple Coast ice streams. The map confirms earlier estimates of deceleration on Whillans Ice Stream. Comparison with bed elevation data indicates that subglacial topography and the location of consolidated sediment play a strong role in determining the location of the tributaries feeding the ice streams. Force balance estimates based on these data indicate that the tributaries have beds nearly an order of magnitude stronger than those beneath many of the ice streams. We have used a theoretical analysis to examine the controls on fast flow. This analysis suggests that ice plains (very wide ice streams) are inherently unstable. This instability may be responsible for the current deceleration on the Ice Plain of Whillans Ice Stream and the shutdown of Ice Stream C 150 years ago. Thinning-induced reductions indriving stress may also explain some of the observed deceleration, particularly in upstream areas. The active portions of Ice Stream C coincide well with the areas where we estimate that melt should be taking place. Current topography and inferences of large thickening following a shutdown suggest the upstream migration of a stagnation front that initiated at the ice plain. Uncertainty remains about the basal conditions on Ice Stream D, while the basal resistance on Ice Stream E is large enough to ensure basal melting. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Calif Santa Cruz, Dept Earth Sci, Santa Cruz, CA 95064 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Washington, Dept Earth & Space Sci, Seattle, WA 98195 USA. RP Joughin, I (reprint author), CALTECH, Jet Prop Lab, M-S 300-235,4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM ian@radar-sci.jpl.nasa.gov; tulaczyk@es.ucsc.edu; bob@igloo.gsfc.nasa.gov; sprice@geophys.washington.edu RI Joughin, Ian/A-2998-2008; Price, Stephen /E-1568-2013 OI Joughin, Ian/0000-0001-6229-679X; Price, Stephen /0000-0001-6878-2553 NR 79 TC 102 Z9 102 U1 3 U2 31 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 NOV PY 2002 VL 107 IS B11 AR 2289 DI 10.1029/2001JB001029 PG 22 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 637RR UT WOS:000180527200024 ER PT J AU Lundgren, P Stramondo, S AF Lundgren, P Stramondo, S TI Slip distribution of the 1997 Umbria-Marche earthquake sequence: Joint inversion of GPS and synthetic aperture radar interferometry data SO JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH LA English DT Article DE earthquake; interferometry; radar; GPS; SAR; fault slip ID MODELING COSEISMIC DISPLACEMENTS; STATIC STRESS CHANGES; SAR INTERFEROMETRY; TURKEY EARTHQUAKE; FAULT INTERACTION; TENSILE FAULTS; HALF-SPACE; SURFACE; DEFORMATION; AFTERSHOCKS AB [1] In September-October 1997 a seismic sequence struck the southern part of the Umbria-Marche region in central Italy. The three largest earthquakes took place on 26 September (0033 UT, M-w 5.7; 09: 40 GU, M-w 6.0) near Colfiorito, and on 14 October (M-w 5.6) near Sellano. We present a slip model for the main sequence over two separate fault planes. We use previously published Global Positioning System (GPS) and differential interferometric synthetic aperture radar (DInSAR) data as well as new DInSAR data covering the Sellano event as input to a simulated annealing solution for the distribution of fault slip. The combination of both types of geodetic data as well as the combination of SAR interferograms from both ascending and descending satellite tracks allows us to make a more complete geodetically based assessment of the fault slip for these earthquakes. For the solutions presented here we required the slip distribution to match the observed surface displacements while maintaining a total scalar seismic moment approximately equal to the seismologically inferred moments for this sequence. We find the slip was concentrated in a zone at 4-5.5 km depth with a shallower tail extending to near the surface at the northern end of the Colfiorito sequence. For both the second Colfiorito event and the Sellano event, individual patches were calculated with maximum slip of 2 m, implying stress drops as high as 20 MPa. Coulomb stress calculations show that the coseismic slip distribution for the Colfiorito events facilitated slip of the adjacent Sellano earthquake. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Ist Nazl Geofis, I-00161 Rome, Italy. RP CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM paul@weed.jpl.nasa.gov; sstramon@ingv.it NR 34 TC 23 Z9 23 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9313 EI 2169-9356 J9 J GEOPHYS RES-SOL EA JI J. Geophys. Res.-Solid Earth PD NOV PY 2002 VL 107 IS B11 AR 2316 DI 10.1029/2000JB000103 PG 9 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 637RR UT WOS:000180527200051 ER PT J AU Wu, XP Watkins, MM Ivins, ER Kwok, R Wang, P Wahr, JM AF Wu, XP Watkins, MM Ivins, ER Kwok, R Wang, P Wahr, JM TI Toward global inverse solutions for current and past ice mass variations: Contribution of secular satellite gravity and topography change measurements SO JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH LA English DT Article DE gravity; inverse; ice; rebound; GRACE; sea level ID GLACIAL-ISOSTATIC-ADJUSTMENT; DEEP MANTLE VISCOSITY; PLEISTOCENE DEGLACIATION; ELEVATION CHANGE; POLAR ICE; SHEET; BALANCE; GRACE; EARTH; PREDICTIONS AB [1] We investigate the accuracy and resolution of estimating global ice mass variations using secular gravity and ice elevation change observations by the planned Gravity Recovery and Climate Experiment (GRACE) and ICESat missions. The gravity and altimetry data combination can determine the total bedrock uplift rate with root-mean-square (RMS) errors of 0.2-1.3 mm/yr when Gaussian averaged over a half scale of 250 km. Moreover, covariance analyses indicate that the mean snow compaction error can be constrained to the level of 3 mm/yr in equivalent Antarctic ice thickness change. The mean Antarctic present-day ice mass change could then be determined to about 4 mm/yr. For a known viscosity profile, such data sets provide a spatial estimate of a linear combination of the late Pleistocene deglaciation and a more recent past trend (last few thousand years) in the Greenland and Antarctica mass balance. For example, when the linear rate of the recent past trend is estimated solely for ice history, the RMS errors of the 450-km Gaussian averages range between 1 and 3 cm/yr. Although contaminated by the signature of present-day hydrological variations over the deglaciated areas, the 450-km Gaussian-averaged Last Glacial Maximum height of the ancient ice sheets can be determined to a RMS level of 300 m. The mean recovery errors are less than 100 m. However, the gravity/altimeter data cannot resolve the load history and lower mantle viscosity simultaneously. Additional data such as relative sea level records must be invoked to overcome this difficulty. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Colorado, Dept Phys, Boulder, CO 80309 USA. Univ Colorado, CIRES, Boulder, CO 80309 USA. RP Wu, XP (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 238-600, Pasadena, CA 91109 USA. EM Xiaoping.Wu@jpl.nasa.gov; mmw@cobra.jpl.nasa.gov; eri@scn1.jpl.nasa.gov; ron@radar-sci.jpl.nasa.gov; wangp@azalea.jpl.nasa.gov; wahr@longo.colorado.edu RI Kwok, Ron/A-9762-2008 OI Kwok, Ron/0000-0003-4051-5896 NR 43 TC 8 Z9 8 U1 0 U2 5 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9313 EI 2169-9356 J9 J GEOPHYS RES-SOL EA JI J. Geophys. Res.-Solid Earth PD NOV PY 2002 VL 107 IS B11 AR 2291 DI 10.1029/2001JB000543 PG 14 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 637RR UT WOS:000180527200026 ER PT J AU Burlaga, LF Forman, MA AF Burlaga, LF Forman, MA TI Large-scale speed fluctuations at 1 AU on scales from 1 hour to approximate to 1 year: 1999 and 1995 SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article DE solar wind; multiscale structure; probability distribution functions; statistical properties ID SOLAR-WIND; INTERMITTENT TURBULENCE; MULTIFRACTAL STRUCTURE; DEVELOPED TURBULENCE; RECURRENT STREAMS; PLASMA; 1-AU; DISTRIBUTIONS; FRACTALS; SPECTRA AB [1] This paper describes the solar wind speed fluctuations, V(tau(i)), observed on a wide range of scales (from 1 hour to; approximate to1 year) at 1 AU, both during 1999 approaching solar maximum and during 1995 during the descending phase of solar activity. The fluctuations extend from the inertial turbulence range, throughout the scales dominated by interaction regions and streams, and through the largest scales where the fluctuations reflect the variability of the characteristics of the streams. The general properties of the fluctuations of the speed differences, dVn, on all of these scales, tau(n), are described by the three functions: skewness S(tau(n)), kurtosis K(tau(n)), and standard deviation SD(tau(n)). These three functions have the same qualitative form for both the 1999 data and the 1995 data, in the range of scales of tau(n) = 10.7-341 days (the "Gaussian range"), S(tau(n)) approximate to 0, and K(tau(n)) approximate to 3, consistent with Gaussian distribution functions for both 1999 and 1995. The skewness is positive for tau(n) < 10.7 days and is maximum at a characteristic scale, which is 4 hours for the 1999 data and &AP;8 hours for the 1995 data. A more detailed description of the fluctuations is provided by the probability distribution functions (PDFs) for dVn. In the range τ(n) > 10.7 days, the PDFs are Gaussian for the 1999 data and approximately Gaussian for the 1995 period. For scales defined by streams, the PDFs are like Gaussians but fatter on the dVn > 0 side. The PDFs are cubic on a semilog scale for the 1999 data and are approximately cubic for the 1995 data. At scales characteristic of the sizes of interaction regions, the PDFs have a large tail for dVn > 0 that is produced by the large positive dVn at leading edges of streams. At the smallest scales, the PDFs have a form that is characteristic of intermittent turbulence. The power spectra for the 1999 and 1995 data are power laws in frequency throughout the interaction region range and the stream range, the slopes being beta = -2.02 +/- 0.01 and -2.12 +/- 0.04, respectively, consistent with the dominance of shocks and jumps over turbulence. The fluctuations of V(tau(n)) have a multifractal scaling structure, described by a function s(q), the exponent of the structure function versus moment number q in the inertial range, the interaction region range, and extending to the stream range. In the interaction region and stream ranges, s(3) > 1. C1 NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. SUNY Stony Brook, Dept Phys & Astron, Stony Brook, NY 11794 USA. RP Burlaga, LF (reprint author), NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. NR 50 TC 24 Z9 24 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 NOV PY 2002 VL 107 IS A11 AR 1403 DI 10.1029/2002JA009271 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 634UU UT WOS:000180360500070 ER PT J AU Burlaga, LF Ness, NF Wang, YM Sheeley, NR AF Burlaga, LF Ness, NF Wang, YM Sheeley, NR TI Heliospheric magnetic field strength and polarity from 1 to 81 AU during the ascending phase of solar cycle 23 SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article DE magnetic field; heliospheric structure; sector zone; polarity; Voyager ID NORTH-SOUTH FLOWS; WIND SPEED; ULYSSES OBSERVATIONS; SECTOR STRUCTURE; CURRENT SHEET; HELIOGRAPHIC LATITUDES; VOYAGER-2 OBSERVATIONS; DISTANT HELIOSPHERE; INTERACTION REGIONS; OUTER HELIOSPHERE AB [1] The Voyager 1 (V1) observations of the heliospheric magnetic field strength B agree with Parker's model of the global heliospheric magnetic field from 1 to 81.0 AU and from 1978 to 2001.34 when one considers the solar cycle variations in the source magnetic field strength and the latitude/time variation in the solar wind speed. In particular, Parker's model, without adjustable parameters, describes the general tendency for B to decrease with increasing distance R from the Sun, the three broad increases of B around 1980, 1990, and 2000, and the minima of B in 1987 and 1997. During 1987 and 1997, B appears to be lower than Parker's model predicts, but that can be attributed to the presence of a heliospheric vortex street at these times and/or uncertainty in the observations. There is no evidence for a significant flux deficit increasing monotonically from 1 to 81.0 AU. By extrapolating these results and considering the limitations of the observations, V1 should continue to make useful measurements during the next few years at least. The magnetic field polarity in the distant heliosphere at V1 and Voyager 2 (V2) changed during the ascending phase of solar cycle 23. In the Northern Hemisphere, V1 observed a decrease in the percentage of positive polarities from; approximate to100% during 1997 to approximate to50% during 2000. In the Southern Hemisphere, V2 observed the opposite behavior, an increase in the percentage of positive polarities from approximate to0% during 1997 to approximate to50% during 2000. The variation of magnetic polarity observed by V1 and V2 was caused by the increasing latitudinal width of the sector zone with increasing solar activity, which in turn was related to the increasing maximum latitudinal extent and the decreasing minimum latitudinal extent of the footprints of the heliospheric current sheet (HCS). There was a tendency for the speed and proton temperature to decrease and the density to increase at V2 from 1997 (when it observed flows from polar coronal holes) to 2001 (when it observed more complex and dynamic flows). C1 NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. Univ Delaware, Bartol Res Inst, Newark, DE 19716 USA. USN, Res Lab, EO Hulburt Ctr Space Res, Washington, DC 20375 USA. RP NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Mail Code 692,Bldg 2,Rm 127, Greenbelt, MD 20771 USA. EM burlaga@lepvax.gsfc; nfness@bartol.udel.edu; ywang@yucca.nrl.navy.mil; sheeley@spruce.nrl.navy.mil NR 66 TC 41 Z9 41 U1 1 U2 1 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 NOV PY 2002 VL 107 IS A11 AR 1410 DI 10.1029/2001JA009217 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 634UU UT WOS:000180360500077 ER PT J AU Forsyth, RJ Balogh, A Smith, EJ AF Forsyth, RJ Balogh, A Smith, EJ TI The underlying direction of the heliospheric magnetic field through the Ulysses first orbit SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article DE heliospheric magnetic field; interplanetary magnetic field; IMF; Ulysses; Parker; spiral ID HIGH HELIOGRAPHIC LATITUDES; SPEED SOLAR-WIND; SOUTH; LINES; WAVES AB [1] Between February 1992 and April 1998 the Ulysses spacecraft carried out the first survey of how the properties of the solar wind and heliospheric magnetic field vary with latitude during the declining and minimum phases of the solar cycle. In this paper we report on how the underlying direction of the heliospheric magnetic field varied through the various phases of the Ulysses first solar orbit. To a first approximation both the azimuth angle of the magnetic field with respect to the radial direction and the meridional (north-south) angle agree with the predictions of the simple Parker spiral model. However, there are a number of notable deviations. For example, at high southerly latitudes the most probable azimuth angle was found to be similar to24degrees more tightly wound than expected, although the mean angle was less tightly wound than expected. In contrast, at high northerly latitudes, the most probable azimuth angle agreed with the Parker prediction, but the meridional angle showed a notably double peaked distribution. We discuss possible interpretations of these and other results in the context of recent ideas on the large-scale behavior of the heliospheric magnetic field. No evidence of a heliolongitude dependence of the underlying field, predicted by one model, is found. It is suggested that the presence of large-scale Alfven waves in the high-latitude heliosphere may lead to double peak distributions of the magnetic field angles, consistent with evidence that longer time averaging removes some of the unexpected features noted in the results. Our analysis does not rule out that systematic deviations due to field line foot point motions could be present but suggests that their amplitude may be too low to be reliably detected in in situ heliospheric magnetic field data. C1 Univ London Imperial Coll Sci Technol & Med, Blackett Lab, London SW7 2BW, England. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Forsyth, RJ (reprint author), Univ London Imperial Coll Sci Technol & Med, Blackett Lab, London SW7 2BW, England. NR 29 TC 23 Z9 23 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD NOV PY 2002 VL 107 IS A11 AR 1405 DI 10.1029/2001JA005056 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 634UU UT WOS:000180360500072 ER PT J AU Kliore, AJ Anabtawi, A Herrera, RG Asmar, SW Nagy, AF Hinson, DP Flasar, FM AF Kliore, AJ Anabtawi, A Herrera, RG Asmar, SW Nagy, AF Hinson, DP Flasar, FM TI Ionosphere of Callisto from Galileo radio occultation observations SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article DE Callisto; ionosphere; atmosphere; radio; occultation ID ATMOSPHERE; JUPITER; EUROPA AB [1] An ionosphere has been detected at Callisto by the Galileo spacecraft, using the radio occultation technique. There were four usable occultations by Callisto, providing eight observation opportunities, all equatorial and near the terminator (entry and exit observations). Detectable electron densities were obtained from six of the eight opportunities. It was found that a detectable ionosphere was only present at the observed location when the trailing hemisphere of Callisto, which is the one that is impacted by the corotating plasma of Jupiter's magnetosphere, was illuminated by the Sun. Two of these observations yielded well-defined electron density profiles, having peak densities of 15,300 and 17,400 cm(-3) at altitudes of 27.2 and 47.6 km and topside plasma scale heights of 29.6 and 49.0 km. Four different methods, based on both photoionization and electron impact ionization, were used to obtain estimates of the corresponding neutral densities at the surface. The various assumptions inherent in these methods required using a variety of parameters, (cross sections, rate constants, etc.) all with their associated uncertainties. It was rather surprising and reassuring to find that all of the methods used to estimate the surface neutral density gave very similar results in each of the eight cases. The estimated values fall between 1 and 3 x 10(10) cm(-3), leading to an estimate for the column density of from 3 to 4 x 10(16) cm(-2). C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Michigan, Space Phys Res Lab, Ann Arbor, MI 48109 USA. Stanford Univ, Ctr Radar Astron, Stanford, CA 94305 USA. NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. RP Kliore, AJ (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Flasar, F Michael/C-8509-2012 NR 17 TC 19 Z9 19 U1 1 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD NOV PY 2002 VL 107 IS A11 AR 1407 DI 10.1029/2002JA009365 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 634UU UT WOS:000180360500074 ER PT J AU Vassiliadis, D Klimas, AJ Kanekal, SG Baker, DN Weigel, RS AF Vassiliadis, D Klimas, AJ Kanekal, SG Baker, DN Weigel, RS TI Long-term-average, solar cycle, and seasonal response of magnetospheric energetic electrons to the solar wind speed SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article DE radiation belts; inner magnetosphere; solar cycle; seasonal variability; relativistic electrons; magnetic storms ID RADIATION BELT ELECTRONS; RELATIVISTIC ELECTRONS; SEMIANNUAL VARIATION; GEOMAGNETIC-ACTIVITY; GEOSTATIONARY ORBIT; ACCELERATION; PREDICTION AB [1] Among the interplanetary activity parameters the solar wind speed is the one best correlated with the energetic electron fluxes in the inner magnetosphere. We examine the radial and temporal characteristics of the 2-6 MeV electron response, approximating it in this paper with linear filters. The filter response is parameterized by the time delay (tau), measured from the time of solar wind impact, and the L shell (L). We examine solar cycle and seasonal effects using an 8-year-long database of Solar, Anomalous, and Magnetospheric Particle Explorer (SAMPEX)/ Proton Electron Telescope (PET) measurements at the radial range L = 1.1-10. The main peak P-1 of the long-term-average response is at (tau, L) = (2, 5.3) and has a simultaneous response over a wide range of radial distances, DeltaL = 5. The duration of the response after the peak is inversely proportional to the L shell. The central part of the inner magnetosphere (L = 3.7-5.75) has a much more prolonged response (>10 days) than other parts. Prior to the main response, P-1, a brief response, P-0, of typically lower amplitude appears at (tau, L) = (0, 3), probably as a quasi-adiabatic response to the compression of the magnetosphere by the solar wind pressure. Over the solar cycle the variation in solar wind input results in a systematic change of the position, amplitude, radial extent, and duration of the two peaks: during solar wind minimum the quasi-adiabatic peak disappears, and the radial size of the responding region decreases; both are responses to low-density, high-speed streams. During solar minimum, the duration is at least 3 days (30%) longer than average, probably due to the sustained solar wind input. Systematic variations appear also as a function of season due to several magnetic and fluid effects. During equinoxes the coupling is stronger, and the duration is longer (by at least 2 days) compared to solstices. Between the two equinoxes the fall response has a significantly higher amplitude and longer duration than the spring equinox response. This is at least partly due to the higher GSE B-y component during the observation time, which acts to increase the effective GSM B-z component according to the Russell-McPherron effect. The seasonal modulation of the response is consistent with the variation in the fluxes themselves [Baker et al., 1999]. The modulation is discussed in terms of the equinoctial and axial hypotheses [Boller and Stolov, 1970; Russell and McPherron, 1973; Cliver et al., 2000]. C1 NASA, Goddard Space Flight Ctr, Univ Space Res Assoc, Greenbelt, MD 20771 USA. Univ Colorado, Atmospher & Space Phys Lab, Boulder, CO 80309 USA. NASA, Goddard Space Flight Ctr, Natl Res Council, Greenbelt, MD 20771 USA. RP Vassiliadis, D (reprint author), NASA, Goddard Space Flight Ctr, Univ Space Res Assoc, Code 690-2, Greenbelt, MD 20771 USA. NR 31 TC 48 Z9 49 U1 1 U2 5 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD NOV PY 2002 VL 107 IS A11 AR 1383 DI 10.1029/2001JA000506 PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 634UU UT WOS:000180360500050 ER PT J AU Wibberenz, G Richardson, IG Cane, HV AF Wibberenz, G Richardson, IG Cane, HV TI A simple concept for modeling cosmic ray modulation in the inner heliosphere during solar cycles 20-23 SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article DE cosmic rays; interplanetary magnetic field; solar cycle; solar magnetic field; cosmic ray modulation ID PIONEER SPACECRAFT MEASUREMENTS; INTERPLANETARY MAGNETIC-FIELD; DEPENDENT DRIFT MODEL; ENERGETIC PARTICLES; RIGIDITY DEPENDENCE; INTERACTION REGIONS; OUTER HELIOSPHERE; DIFFUSION TENSOR; GRADIENTS; MINIMUM AB [1] Recent observations suggest a close relationship between the evolution of the solar magnetic field and high-energy cosmic ray modulations at 1 AU on timescales of greater than or similar to 1 year. We investigate this relationship using the simple concept that changes in the solar magnetic field propagate from the Sun and cause a change in the radial diffusion coefficient, assumed to scale as some inverse power of the interplanetary magnetic field (IMF) magnitude (K proportional to B-n). Increases in the IMF cause a reduction in the cosmic ray density in the inner heliosphere. A continuous recovery process is also assumed to operate, represented by a timescale tau which physically is related to particle entry into the depleted regions of the heliosphere by drift and diffusion processes. We integrate numerically the spherically symmetric equation representing this process, and incorporate the observed variations of the parameters included in the equation. The concept is able to account for the variations in cosmic ray intensity at 1 AU during solar cycles 20-23 remarkably successfully using physically plausible values of n similar to 1-2. An important requirement is that recovery times are shorter (tau similar to 30 days for >2 GV cosmic rays observed by neutron monitors) during epochs when the polarity of the solar global magnetic field A > 0, than when A < 0 (tau similar to 100 days). This dependence has a simple physical interpretation, since particle inflows into the inner heliosphere are expected to be faster from over the poles in A > 0 epochs than along the heliospheric current sheet when A < 0. We also identify a period around solar maximum when recovery times are long, consistent with the disappearance of latitudinal intensity gradients observed by Ulysses approaching the maximum of solar cycle 23. This period commences when the axisymmetric component of the solar open flux reaches a minimum, essentially corresponding to the disappearance of the polar coronal holes, prior to solar maximum. Part of the energy dependence of the size of cosmic ray intensity variations can be accounted for by recovery times that decrease with increasing particle energy. Despite the simplicity of the concept, we suggest that it provides important insight into the relationships between variations of the solar magnetic field, interplanetary parameters, and cosmic ray modulation. C1 Univ Kiel, Inst Expt & Angew Phys, D-24118 Kiel, Germany. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. Univ Maryland, Dept Astron, College Pk, MD 20742 USA. Univ Tasmania, Sch Math & Phys, Hobart, Tas, Australia. RP Univ Kiel, Inst Expt & Angew Phys, Olshaussenstr 40, D-24118 Kiel, Germany. EM wibberenz@physik.uni-kiel.de; richardson@lheavx.gsfc.nasa.gov; hilary.cane@utas.edu.au NR 60 TC 27 Z9 27 U1 0 U2 1 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 NOV PY 2002 VL 107 IS A11 AR 1353 DI 10.1029/2002JA009461 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 634UU UT WOS:000180360500020 ER PT J AU Wu, CC Lepping, RP AF Wu, CC Lepping, RP TI Effect of solar wind velocity on magnetic cloud-associated magnetic storm intensity SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article DE magnetic cloud; magnetic storm; solar wind speed; storm intensity prediction; storm intensity ID FIELDS; DST AB [1] We investigate geomagnetic storm activity during periods of 135 magnetic clouds identified with hourly averages of OMNI data from 1965 to 1998. It is found that the storm Dst index correlates well with both the B-z component (correlation coefficient, c.c. = -0.86) and the "rectified" electric field VBS (c.c. = -0.88) but does not correlate well with solar wind speed (c.c. = -0.58), indicating that the role of magnetic cloud speed in predicting storm intensity is a minor one. Solar wind speed does become important in predicting Dst for the studied cloud events when high solar wind speeds are considered. The correlation coefficient (c.c.) for Dst versus B-z increases dramatically when the solar wind speed exceeds 600 km/s. For example, the c.c. for Dst versus B-z is 0.99 for speeds between 600 and 750 km/s (15 events). This implies that solar wind velocity is also important indirectly for predicting the storm intensity when using B-z as a direct predictor. Specially, over the next 2 or 3 years, cloud speed is expected to increase, on average, as has already been observed. This provides us a good opportunity to estimate the intensity of cloud-associated geomagnetic storms by using the observed upstream B-z. C1 NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. RP Wu, CC (reprint author), NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. NR 15 TC 35 Z9 38 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 NOV PY 2002 VL 107 IS A11 AR 1346 DI 10.1029/2002JA009396 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 634UU UT WOS:000180360500013 ER PT J AU Shin, JY Balas, GJ Kaya, MA AF Shin, JY Balas, GJ Kaya, MA TI Blending methodology of linear parameter varying control synthesis of F-16 aircraft system SO JOURNAL OF GUIDANCE CONTROL AND DYNAMICS LA English DT Article; Proceedings Paper CT AIAA Guidance Navigation and Control Conference CY AUG 06-09, 2001 CL MONTREAL, CANADA SP AIAA ID LATERAL-DIRECTIONAL AXIS; POWERED APPROACH; MISSILE; DESIGN AB The design of a linear parameter varying (LPV) controller for the F-16 longitudinal axes over the entire flight envelope, using a blending methodology that lets an LPV controller preserve regional optimal solutions over each parameter subset and reduces computational costs for synthesizing an LPV controller, is presented. Three blending LPV controller synthesis methodologies are applied to control F-16 longitudinal axes. By the use of a function substitution method, a quasi-LPV model of the F-16 longitudinal axes is constructed from the nonlinear equations of motion over the entire flight envelope, including nontrim regions, to facilitate synthesis of LPV controllers for the F-16 aircraft. The nonlinear simulations of the blended LPV controller show that the desired performance and robustness objectives are achieved across all altitude variations. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. Univ Minnesota, Dept Aerosp Engn & Mech, Minneapolis, MN 55455 USA. Univ Calif Berkeley, Dept Mech Engn, Berkeley, CA 94720 USA. RP Shin, JY (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 20 TC 25 Z9 25 U1 0 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0731-5090 J9 J GUID CONTROL DYNAM JI J. Guid. Control Dyn. PD NOV-DEC PY 2002 VL 25 IS 6 BP 1040 EP 1048 DI 10.2514/2.5008 PG 9 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA 613CB UT WOS:000179112600006 ER PT J AU Johnson, AE Klumpp, AR Collier, JB Wolf, AA AF Johnson, AE Klumpp, AR Collier, JB Wolf, AA TI Lidar-based hazard avoidance for safe landing on Mars SO JOURNAL OF GUIDANCE CONTROL AND DYNAMICS LA English DT Article AB Hazard avoidance is a key technology for landing large payloads safely on the surface of Mars. During haz-' ard avoidance, sensors and computing onboard the lander are utilized to detect hazards in the landing zone, autonomously select a location free of hazards, and then generate a trajectory that retargets the lander to the safe landing site. Algorithms are described for scanning lidar (light detection and ranging)-based hazard detection, safe site selection, and powered landing guidance designed for Mars landing. The performance of these algorithms is quantified using a closed-loop simulation of hazard avoidance, which includes a synthetic Martian terrain generator, a scanning lidar model, and the required ' hazard avoidance and powered landing guidance algorithms. Preliminary results show that the proposed hazard avoidance algorithms are effective at detecting hazards and guiding the lander to a safe landing site. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Johnson, AE (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 11 TC 18 Z9 26 U1 0 U2 5 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0731-5090 J9 J GUID CONTROL DYNAM JI J. Guid. Control Dyn. PD NOV-DEC PY 2002 VL 25 IS 6 BP 1091 EP 1099 DI 10.2514/2.4988 PG 9 WC Engineering, Aerospace; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA 613CB UT WOS:000179112600012 ER PT J AU Lee, H Kok, P Dowling, JP AF Lee, H Kok, P Dowling, JP TI A quantum Rosetta stone for interferometry SO JOURNAL OF MODERN OPTICS LA English DT Article; Proceedings Paper CT 32nd Winter Symposium on the Physics of Quantum Electronics CY JAN 06-10, 2002 CL SNOWBIRD, UT ID OPTICAL FREDKIN GATE; EXPLOITING ENTANGLEMENT; DIFFRACTION LIMIT; PHASE MEASUREMENT; SPIN COHERENCE; HUMPTY-DUMPTY; NOISE LIMITS; LOGIC GATE; STATES; LITHOGRAPHY AB Heisenberg-limited measurement protocols can be used to gain an increase in measurement precision over classical protocols. Such measurements can be implemented using, for example, optical Mach-Zehnder interferometers and Ramsey spectroscopes. We address the formal equivalence between the Mach-Zehnder interferometer, the Ramsey spectroscope and a generic quantum logic circuit. Based on this equivalence we introduce the 'quantum Rosetta stone', and we describe a projective-measurement scheme for generating the desired correlations between the interferometric input states in order to achieve Heisenberg-limited sensitivity. The Rosetta stone then tells us that the same method should work in atom spectroscopy. C1 CALTECH, Jet Prop Lab, Quantum Comp Technol Grp, Sect 367, Pasadena, CA 91109 USA. RP CALTECH, Jet Prop Lab, Quantum Comp Technol Grp, Sect 367, MS 126-347,4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Kok, Pieter/B-1658-2010; DOWLING, JONATHAN/L-2749-2013 NR 60 TC 180 Z9 181 U1 3 U2 14 PU TAYLOR & FRANCIS LTD PI ABINGDON PA 2-4 PARK SQUARE, MILTON PARK, ABINGDON OR14 4RN, OXON, ENGLAND SN 0950-0340 EI 1362-3044 J9 J MOD OPTIC JI J. Mod. Opt. PD NOV-DEC PY 2002 VL 49 IS 14-15 SI SI BP 2325 EP 2338 DI 10.1080/0950034021000011536 PG 14 WC Optics SC Optics GA 641WR UT WOS:000180770500006 ER PT J AU Strekalov, DV Stowe, MC Chekhova, MV Dowling, JP AF Strekalov, DV Stowe, MC Chekhova, MV Dowling, JP TI Two-photon processes in faint biphoton fields SO JOURNAL OF MODERN OPTICS LA English DT Article; Proceedings Paper CT 32nd Winter Symposium on the Physics of Quantum electronics CY JAN 06-10, 2002 CL SNOWBIRD, UTAH ID INTERFEROMETRIC OPTICAL LITHOGRAPHY; PARAMETRIC DOWN-CONVERSION; QUANTUM TELEPORTATION; 2-PHOTON INTERFERENCE; 2 PHOTONS; ENTANGLEMENT; DIFFRACTION; EXCITATION; LIGHT; STATE AB The goal of this research is to determine and study a physical system that will enable a fast and intrinsically two-photon detector, which would be of interest for quantum information and metrology applications. We consider two types of two-photon processes that can be observed using a very faint, but quantum-correlated biphoton field. These are optical up-conversion and an external photoelectric effect. We estimate the correlation enhancement factor for the biphoton light compared to coherent light, report and discuss the preliminary experimental results. C1 CALTECH, Jet Prop Lab, Quantum Comp Technol Grp, Sect 367, Pasadena, CA 91109 USA. Moscow MV Lomonosov State Univ, Moscow, Russia. RP Strekalov, DV (reprint author), CALTECH, Jet Prop Lab, Quantum Comp Technol Grp, Sect 367, MS 300-123,4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI DOWLING, JONATHAN/L-2749-2013; Chekhova, Maria/A-4659-2017 OI Chekhova, Maria/0000-0002-3399-2101 NR 40 TC 7 Z9 7 U1 0 U2 1 PU TAYLOR & FRANCIS LTD PI ABINGDON PA 4 PARK SQUARE, MILTON PARK, ABINGDON OX14 4RN, OXON, ENGLAND SN 0950-0340 J9 J MOD OPTIC JI J. Mod. Opt. PD NOV-DEC PY 2002 VL 49 IS 14-15 SI SI BP 2349 EP 2364 DI 10.1080/0950034021000038915 PG 16 WC Optics SC Optics GA 641WR UT WOS:000180770500008 ER PT J AU Jackson, D Hockney, G Dowling, J AF Jackson, D Hockney, G Dowling, J TI Optical communication noise rejection using correlated photons SO JOURNAL OF MODERN OPTICS LA English DT Article; Proceedings Paper CT 32nd Winter Symposium on the Physics of Quantum electronics CY JAN 06-10, 2002 CL SNOWBIRD, UTAH ID PAIRS AB This paper describes a completely new way to perform noise rejection using a two-photon sensitive detector and taking advantage of the properties of correlated photons to improve an optical communications link in the presence of uncorrelated noise. In particular, a detailed analysis is made of the case where a classical link would be saturated by an intense background, such as when a satellite is in front of the sun, and identifies a regime where the quantum correlating system has superior performance. C1 CALTECH, Jet Prop Lab, Quantum Comp Technol Grp, Pasadena, CA 91109 USA. RP Jackson, D (reprint author), CALTECH, Jet Prop Lab, Quantum Comp Technol Grp, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 9 TC 3 Z9 3 U1 1 U2 1 PU TAYLOR & FRANCIS LTD PI ABINGDON PA 4 PARK SQUARE, MILTON PARK, ABINGDON OX14 4RN, OXON, ENGLAND SN 0950-0340 J9 J MOD OPTIC JI J. Mod. Opt. PD NOV-DEC PY 2002 VL 49 IS 14-15 SI SI BP 2383 EP 2388 DI 10.1080/0950034021000011338 PG 6 WC Optics SC Optics GA 641WR UT WOS:000180770500010 ER PT J AU Masson, GS Stone, LS AF Masson, GS Stone, LS TI From following edges to pursuing objects SO JOURNAL OF NEUROPHYSIOLOGY LA English DT Article ID EYE-MOVEMENTS; SMOOTH PURSUIT; MOTION INTEGRATION; TEMPORAL DYNAMICS; PERCEPTION; INITIATION; INPUTS; MT AB Primates can generate accurate, smooth eye-movement responses to moving target objects of arbitrary shape and size, even in the presence of complex backgrounds and/or the extraneous motion of non-target objects. Most previous studies of pursuit have simply used a spot moving over a featureless background as the target and have thus neglected critical issues associated with the general problem of recovering object motion. Visual psychophysicists and theoreticians have shown that, for arbitrary objects with multiple features at multiple orientations, object-motion estimation for perception is a complex, multi-staged, time-consuming process. To examine the temporal evolution of the motion signal driving pursuit, we recorded the tracking eye movements of human observers to moving line-figure diamonds. We found that pursuit is initially biased in the direction of the vector average of the motions of the diamond's line segments and gradually converges to the true object-motion direction with a time constant of approximately 90 ms. Furthermore, transient blanking of the target during steady-state pursuit induces a decrease in tracking speed, which, unlike pursuit initiation, is subsequently corrected without an initial direction bias. These results are inconsistent with current models in which pursuit is driven by retinal-slip error correction. They demonstrate that pursuit models must be revised to include a more complete visual afferent pathway, which computes, and to some extent latches on to, an accurate estimate of object direction over the first hundred milliseconds or so of motion. C1 NASA, Ames Res Ctr, Human Factors Res & Technol Div, Moffett Field, CA 94035 USA. CNRS, Ctr Rech Neurosci Cognit, F-13402 Marseille, France. RP Stone, LS (reprint author), NASA, Ames Res Ctr, Human Factors Res & Technol Div, MS 262-2, Moffett Field, CA 94035 USA. RI MASSON, Guillaume/G-4615-2012 NR 13 TC 49 Z9 49 U1 1 U2 2 PU AMER PHYSIOLOGICAL SOC PI BETHESDA PA 9650 ROCKVILLE PIKE, BETHESDA, MD 20814 USA SN 0022-3077 J9 J NEUROPHYSIOL JI J. Neurophysiol. PD NOV PY 2002 VL 88 IS 5 BP 2869 EP 2873 DI 10.1152/jn.00987.2001 PG 5 WC Neurosciences; Physiology SC Neurosciences & Neurology; Physiology GA 612MW UT WOS:000179080900063 PM 12424320 ER PT J AU Halverson, PG Spero, RE AF Halverson, PG Spero, RE TI Signal processing and testing of displacement metrology gauges with picometre-scale cyclic nonlinearity SO JOURNAL OF OPTICS A-PURE AND APPLIED OPTICS LA English DT Article DE displacement metrology; metrology gauges; interferometry; astrometry; cyclic error; cyclic nonlinearity ID LASER METROLOGY; INTERFEROMETRY; ERRORS AB The Space Interferometry Mission (see http://sim.jpl.nasa.gov) requires displacement metrology gauges with linearity similar to10 pm rms over a distance of several metres. Displacement measuring interferometers are under development to meet these requirements, while also meeting thermal stability, robustness, size and geometry requirements. A persistent difficulty in attaining picometre-class performance with laser interferometric metrology gauges is the problem of 'cyclic error' which may be caused by small amounts of mixing of the interferometer measurement and reference signals. The mixing is caused by crosstalk, both optical and electronic. Other causes of cyclic error have been also found and will be discussed. This paper describes our approach to minimizing the cyclic error with emphasis on signal processing issues and the concurrent development of techniques to detect the error as it is gradually reduced to zero. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Halverson, PG (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 19 TC 15 Z9 15 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 1464-4258 J9 J OPT A-PURE APPL OP JI J. Opt. A-Pure Appl. Opt. PD NOV PY 2002 VL 4 IS 6 BP S304 EP S310 AR PII S1464-4258(02)37569-X DI 10.1088/1464-4258/4/6/373 PG 7 WC Optics SC Optics GA 629VK UT WOS:000180072200032 ER PT J AU Tilburg, CE Hurlburt, HE O'Brien, JJ Shriver, JF AF Tilburg, CE Hurlburt, HE O'Brien, JJ Shriver, JF TI Remote topographic forcing of a baroclinic western boundary current: An explanation for the Southland Current and the pathway of the subtropical front east of New Zealand SO JOURNAL OF PHYSICAL OCEANOGRAPHY LA English DT Article ID ANTARCTIC CIRCUMPOLAR CURRENT; 1/64-DEGREES RESOLUTION; KUROSHIO EXTENSION; CURRENT SYSTEM; PACIFIC-OCEAN; MODEL; SEA; VARIABILITY; DYNAMICS; 1/8-DEGREES AB The Southland Current is a western boundary current adjacent to the South Island of New Zealand and flows along a segment of the Southern Hemisphere subtropical front (STF). The physical mechanisms that govern the behavior of this current and other portions of the STF and subantarctic front (SAF) are investigated using one regional and three global ocean simulations. The three global ocean simulations used in this study are a 1 1/2-layer reduced-gravity linear simulation, a six-layer nonlinear flat-bottom simulation, and a six-layer nonlinear simulation that incorporates vertically compressed, but otherwise realistic, bottom topography confined to the abyssal layer. All three simulations have horizontal spacings of 1/8degrees and are forced with climatological-mean monthly wind stress data. The regional simulation has a horizontal spacing of 1/2degrees and contains two layers, with an idealized bottom topography. The only forcing is supplied by inflow and outflow ports. The pathway of the SAF is shown to be strongly influenced by a barotropic response of the associated flow to bottom topography. Currents associated with the SAF flow along the southern edge of the Campbell Plateau, a large submarine platform southeast of New Zealand. In contrast, the location of the Southland Current and the pathway of the STF east of New Zealand are due to remote forcing of upper-ocean currents by topographically constrained abyssal currents. Whereas most western boundary currents can be described as responses of the ocean to interior Sverdrup flow with some modification, analysis of the numerical simulations within this study shows that the Southland Current is due to a completely different formation mechanism. The presence of the Southland Current and the STF east of New Zealand are instead due to a combination of northward topographic steering of surface-layer thickness gradients approximately 128 east of New Zealand and westward propagation of these perturbed gradients. A portion of the abyssal flow associated with the SAF is shown to form a topographically constrained deep western boundary current (DWBC). This DWBC follows the edge of the Campbell Plateau, eventually flowing generally northward. When the surface zonal flow associated with the STF southeast of New Zealand encounters this meridional abyssal flow, it is advected northward, creating an imbalance in the potential vorticity within the flow. In an attempt to conserve potential vorticity, the perturbed surface-layer thickness gradients propagate westward until they encounter New Zealand's South Island, at which point they form the observed Southland Current. Transport associated with the STF thus flows northward along South Island, eastward along the Chatham Rise, and southward once east of the rise. This formation mechanism and the downstream behavior of the STF are illustrated in a simplified regional simulation that reproduces the pathway of the STF and the location of the western boundary current extremely well. C1 Florida State Univ, Ctr Ocean Atmospher Predict Studies, Tallahassee, FL 32306 USA. NASA, Naval Res Lab, John C Stennis Space Ctr, Stennis Space Ctr, MS USA. RP Tilburg, CE (reprint author), Univ Delaware, Grad Coll Marine Studies, Phys Ocean Sci & Engn Program, 102 Robinson Hall, Newark, DE 19716 USA. NR 39 TC 9 Z9 9 U1 0 U2 5 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 NOV PY 2002 VL 32 IS 11 BP 3216 EP 3232 DI 10.1175/1520-0485(2002)032<3216:RTFOAB>2.0.CO;2 PG 17 WC Oceanography SC Oceanography GA 608FD UT WOS:000178834000017 ER PT J AU Wang, TS Chen, YS Liu, JW Myrabo, LN Mead, FB AF Wang, TS Chen, YS Liu, JW Myrabo, LN Mead, FB TI Advanced performance modeling of experimental laser lightcraft SO JOURNAL OF PROPULSION AND POWER LA English DT Article; Proceedings Paper CT AIAA 39th Aerospace Sciences Meeting and Exhibits CY JAN 08-11, 2001 CL RENO, NEVADA SP Amer Inst Aeronaut & Astronaut ID RADIATION TRANSPORT; FORMULATION; PROPULSION; VEHICLES AB A computational plasma aerodynamics model is developed to study the performance of a laser-propelled lightcraft. The computational methodology is based on a time-accurate, multi-dimensional, finite volume, chemically reacting, unstructured grid pressure-based formulation. The underlying physics are modeled using a building-block approach. The physics modeled include nonequilibrium thermodynamics, nonequilibrium air-plasma finite rate kinetics, specular ray tracing, laser beam energy absorption and refraction by plasma, nonequilibrium plasma radiation, and plasma resonance. A series of transient computations are performed at several laser pulse energy levels and the simulated physics are discussed and compared with those of tests and literatures. The computed impulses and coupling coefficients for the lightcraft compared reasonably well with those of tests conducted on a pendulum apparatus. C1 NASA, George C Marshall Space Flight Ctr, Appl Fluid Dynam Grp, Space Transportat Directorate, Huntsville, AL 35812 USA. Engn Sci Inc, Huntsville, AL 35802 USA. Rensselaer Polytech Inst, Dept Aerosp Engn, Troy, NY 12180 USA. USAF, Res Lab, Prop Directorate, Edwards AFB, CA 93524 USA. RP Wang, TS (reprint author), NASA, George C Marshall Space Flight Ctr, Appl Fluid Dynam Grp, Space Transportat Directorate, Huntsville, AL 35812 USA. NR 36 TC 33 Z9 36 U1 0 U2 3 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0748-4658 J9 J PROPUL POWER JI J. Propul. Power PD NOV-DEC PY 2002 VL 18 IS 6 BP 1129 EP 1138 DI 10.2514/2.6054 PG 10 WC Engineering, Aerospace SC Engineering GA 617UT UT WOS:000179379800001 ER PT J AU Freudenberg, KD Lear, WE Sherif, SA Golliher, EL AF Freudenberg, KD Lear, WE Sherif, SA Golliher, EL TI Mass-based optimization of thermal management and power systems for space applications SO JOURNAL OF PROPULSION AND POWER LA English DT Article ID JET-PUMP; COOLING SYSTEM; PERFORMANCE AB Integration of new and existing technologies for thermal management will be required to meet the challenges associated with the increased need for an efficient, lightweight, heat-rejection system. Subsystem design requirements, such as thermal and mass management, must be brought into the design cycle to establish an optimal configuration. This paper provides a parametric analysis that determines the specific conditions under which a proposed system becomes advantageous from a weight-management standpoint. The analysis can be applied to essentially any space-operated thermally actuated heat pump providing power and/or refrigeration. By applying the techniques demonstrated in this paper, designers can identify and optimize conceptual configurations during the initial prototype development stages to reduce payload weight and increase financial savings. Examples of systems to which this analysis can be applied are presented and quantified. C1 Univ Florida, Dept Mech & Aerosp Engn, Gainesville, FL 32611 USA. NASA, John H Glenn Res Ctr, Thermo Mech Syst Branch, Cleveland, OH 44135 USA. RP Freudenberg, KD (reprint author), Univ Florida, Dept Mech & Aerosp Engn, POB 116300, Gainesville, FL 32611 USA. NR 21 TC 1 Z9 1 U1 0 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0748-4658 J9 J PROPUL POWER JI J. Propul. Power PD NOV-DEC PY 2002 VL 18 IS 6 BP 1161 EP 1169 DI 10.2514/2.6074 PG 9 WC Engineering, Aerospace SC Engineering GA 617UT UT WOS:000179379800004 ER PT J AU Xu, CH Heister, SD AF Xu, CH Heister, SD TI Modeling cavitating venturi flows SO JOURNAL OF PROPULSION AND POWER LA English DT Article ID ATOMIZERS AB Simulations of various venturi orifice cavitating flows were performed using a homogeneous flow model. The dynamics of a bubble response per the Rayleigh-Plesset equation are cast into constitutive equation for the density for the pseudofluid, and the turbulence is approximated by the k - w turbulence model. The computed results show that cavitation develops at the throat and its downstream region grows and collapses in a quasi-periodic fashion. The size of the cavity grows as the cavitation number for the flow is reduced. The mass flow rate through the cavitating venturi oscillates periodically essentially in phase with the vapor cloud in the diffuser. Venturi flow rate, oscillation frequency, and cavitation extent are characterized for a wide range of conditions and are compared against experimental data. Results indicate that computations are accurate to within a few percent in flow rate for the venturis modeled in the project. C1 Purdue Univ, Sch Aeronaut & Astronaut, W Lafayette, IN 47907 USA. NASA, Prop Test Directorate, Stennis Space Ctr, MS 39529 USA. RP Xu, CH (reprint author), Purdue Univ, Sch Aeronaut & Astronaut, 1282 Grissom Hall, W Lafayette, IN 47907 USA. NR 15 TC 8 Z9 9 U1 0 U2 3 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0748-4658 J9 J PROPUL POWER JI J. Propul. Power PD NOV-DEC PY 2002 VL 18 IS 6 BP 1227 EP 1234 DI 10.2514/2.6057 PG 8 WC Engineering, Aerospace SC Engineering GA 617UT UT WOS:000179379800012 ER PT J AU Sondak, DL Gupta, V Orkwis, PD Dorney, DJ AF Sondak, DL Gupta, V Orkwis, PD Dorney, DJ TI Effects of blade count on linearized and nonlinear hot streak clocking simulations SO JOURNAL OF PROPULSION AND POWER LA English DT Article; Proceedings Paper CT AIAA/ASME/SAE/ASEE 37th Joint Propulsion Conference CY JUL 08-11, 2001 CL SALT LAKE CITY, UTAH SP AIAA, ASME, SAE, ASEE ID TURBINE STAGE AB The temperature field exiting gas turbine combustors is highly nonuniform due to streaks of hot fluid directly downstream of combustor fuel nozzles. These hot streaks have been shown to limit the life of turbine blades. Adjusting the positions of hot streaks with respect to nozzle guide vanes, known as hot streak clocking, can be used to help control blade temperatures in gas turbines. Because hot streak clocking predictions require unsteady, three-dimensional simulations, they are very expensive, and various techniques are used to reduce their cost. Two of these techiques are examined, linearized Navier-Stokes solvers and reduced-blade-count simulations. Hot streak clocking simulations have been performed using nonlinear and linearized Navier-Stokes solvers for 1-1-1 and 3-4-3 blade-count (blades per row) configurations. The blade-count effects were examined for each solution technique, and the two solution techniques were compared. It is shown that the linearized technique can be used to capture qualitatively hot streak clocking effects. It is also shown that the reduced-blade-count approximation has a significant impact on predicted surface temperatures. C1 Boston Univ, Off Informat Technol, Boston, MA 02215 USA. Univ Cincinnati, Dept Aerosp Engn, Cincinnati, OH 45221 USA. NASA, George C Marshall Space Flight Ctr, Appl Fluid Dynam Grp, Huntsville, AL 35812 USA. RP Sondak, DL (reprint author), Boston Univ, Off Informat Technol, Boston, MA 02215 USA. NR 20 TC 10 Z9 11 U1 0 U2 2 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0748-4658 J9 J PROPUL POWER JI J. Propul. Power PD NOV-DEC PY 2002 VL 18 IS 6 BP 1273 EP 1279 DI 10.2514/2.6063 PG 7 WC Engineering, Aerospace SC Engineering GA 617UT UT WOS:000179379800018 ER PT J AU Dorney, DJ Griffin, LW Huber, FW Sondak, DL AF Dorney, DJ Griffin, LW Huber, FW Sondak, DL TI Effects of end wall geometry and stacking on supersonic turbine performance SO JOURNAL OF PROPULSION AND POWER LA English DT Article C1 NASA, George C Marshall Space Flight Ctr, Fluid Dynam Anal Branch, Huntsville, AL 35812 USA. Riverbend Design Serv, Palm Beach Gardens, FL 33418 USA. Boston Univ, Off Informat Technol, Boston, MA 02215 USA. RP Dorney, DJ (reprint author), NASA, George C Marshall Space Flight Ctr, Fluid Dynam Anal Branch, Huntsville, AL 35812 USA. NR 5 TC 0 Z9 0 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0748-4658 J9 J PROPUL POWER JI J. Propul. Power PD NOV-DEC PY 2002 VL 18 IS 6 BP 1305 EP 1308 DI 10.2514/2.6068 PG 4 WC Engineering, Aerospace SC Engineering GA 617UT UT WOS:000179379800022 ER PT J AU Foster, JE Patterson, MJ AF Foster, JE Patterson, MJ TI Controlling electron backstreaming phenomena through the use of a transverse magnetic field SO JOURNAL OF PROPULSION AND POWER LA English DT Article ID MULTICUSP PLASMA SOURCE; EXTRACTION C1 NASA, John H Glenn Res Ctr, On Board Prop & Power Grp, Cleveland, OH 44135 USA. RP Foster, JE (reprint author), NASA, John H Glenn Res Ctr, On Board Prop & Power Grp, Lewis Field,MS 301-3,21000 Brookpk Rd, Cleveland, OH 44135 USA. NR 13 TC 0 Z9 0 U1 0 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0748-4658 J9 J PROPUL POWER JI J. Propul. Power PD NOV-DEC PY 2002 VL 18 IS 6 BP 1308 EP 1311 DI 10.2514/2.6069 PG 4 WC Engineering, Aerospace SC Engineering GA 617UT UT WOS:000179379800023 ER PT J AU Carpenter, P Counce, D Kluk, E Nabelek, C AF Carpenter, P Counce, D Kluk, E Nabelek, C TI Characterization of Corning EPMA standard glasses 95IRV, 95IRW, and 95IRX SO JOURNAL OF RESEARCH OF THE NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY LA English DT Article; Proceedings Paper CT Workshop on the Accuracy Barrier in Quantitative EPMA and the Role of Standards CY APR 08-11, 2002 CL NATL INST STAND & TECHNOL, GAITHERSBURG, MD SP Natl Inst Stand & Technol, Chem Sci & Technol Lab, Surface & Microanal Sci Div, Microbeam Anal Soc HO NATL INST STAND & TECHNOL DE Corning; epma; glass; homogeneity; microprobe; standard; trace element; eds; 95IRV; 95IRW; 95IRX AB The preparation, synthesis, and characterization of Corning trace-element glasses 95IRV, 95IRW, and 95IRX by bulk chemical and electron microprobe techniques is discussed. Working values for the doped elements in the 95-series glasses are established. Blank values have been determined by both bulk chemical and electron microprobe analysis, and important x-ray interferences are highlighted. Chemical homogeneity both within a rod cross-section, and along cane length has been documented. These glasses are standard reference materials intended for use as both primary and secondary electron microprobe standards. C1 NASA, George C Marshall Space Flight Ctr, Univ Space Res Assoc, Huntsville, AL 35812 USA. Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Univ Missouri, Dept Geol Sci, Columbia, MO 65211 USA. RP Carpenter, P (reprint author), NASA, George C Marshall Space Flight Ctr, Univ Space Res Assoc, SD46, Huntsville, AL 35812 USA. EM paul.carpenter@msfc.nasa.gov NR 3 TC 9 Z9 9 U1 1 U2 14 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 NOV-DEC PY 2002 VL 107 IS 6 BP 703 EP 718 DI 10.6028/jres.107.057 PG 16 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 643NJ UT WOS:000180867100021 PM 27446763 ER PT J AU Jenkins, C Lassiter, J AF Jenkins, C Lassiter, J TI Introduction: Passive and active materials for gossamer spacecraft SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Editorial Material C1 S Dakota Sch Mines & Technol, Rapid City, SD 57701 USA. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Jenkins, C (reprint author), S Dakota Sch Mines & Technol, Rapid City, SD 57701 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD NOV-DEC PY 2002 VL 39 IS 6 BP 821 EP 821 DI 10.2514/2.3893 PG 1 WC Engineering, Aerospace SC Engineering GA 625FY UT WOS:000179807500001 ER PT J AU Bar-Cohen, Y AF Bar-Cohen, Y TI Electroactive polymers as artificial muscles: A review SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article; Proceedings Paper CT AIAA/ASME/ASCE/AHS/ASC 42nd Structures, Structural Dynamics, and Materials Conference CY APR 16-19, 2001 CL SEATTLE, WASHINGTON SP Amer Inst Aeronaut & Astronaut, ASME, ASCE, AHS, ASC ID LIQUID-CRYSTAL ELASTOMERS; PHASE-TRANSITION; MAGNETIC-FIELD; SHAPE-MEMORY; GELS; ELECTROSTRICTION; ACTUATORS; HYDROGELS; BEHAVIOR; DESIGN AB Electroactive polymers (EAP) are an emerging class of functional materials that respond to electrical stimulation. with large displacement. This attractive characteristic earned them the name artificial muscles. Even though the actuation force and robustness of existing EAP materials require further improvement, there has already been a series of reported successes. The successful applications that were demonstrated include catheter steering element, miniature manipulator, dust wiper, miniature robotic arm, and grippers. Some of the currently considered applications may be difficult to accomplish, and it is important to examine the requirements to the level that current materials can address. Using EAP to replace existing actuators may be a difficult challenge, and therefore it is highly desirable to identify a niche application where it would not need to compete with existing capabilities. The field involves multidisciplines that include materials, chemistry, electromechanics, computers, electronics, etc. A review of the state of the art and some of the challenges to the application of these materials are provided. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Bar-Cohen, Y (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 53 TC 74 Z9 75 U1 5 U2 50 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD NOV-DEC PY 2002 VL 39 IS 6 BP 822 EP 827 DI 10.2514/2.3902 PG 6 WC Engineering, Aerospace SC Engineering GA 625FY UT WOS:000179807500002 ER PT J AU Russell, DA Connell, JW Fogdall, LB AF Russell, DA Connell, JW Fogdall, LB TI Electron, proton, and ultraviolet radiation effects on thermophysical properties of polymeric films SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article; Proceedings Paper CT AIAA/ASME/ASCE/AHS/ASC 42nd Structures, Structural Dynamics, and Materials Conference CY APR 16-19, 2001 CL SEATTLE, WASHINGTON SP Amer Inst Aeronaut & Astronaut, ASME, ASCE, AHS, ASC AB The response of coated thin polymer films to simultaneous ultraviolet, electron, and proton radiation has been evaluated by selected measurements in situ and in the laboratory. Exposures simulated the radiation environment near the Earth-sun Lagrangian points 1 and 2 for five years and similar to1000 ultraviolet equivalent solar hours. Materials evaluated were both commercially available and newly developed aromatic polyimide films aluminized on one side and exposed as second surface mirrors. Effects on solar absorptance, thermal emittance, and tensile properties were measured. The in situ changes in solar absorptance of Kapton(R) and Upilex(R) were less than 0.1, whereas the solar absorptance of TOR and CP films increased by more than 0.3 without saturating. Thermal emittance measurements also showed that the Kapton and Upilex materials increased only 1-2%, but the remaining materials increased 5-8%. Tensile property measurements made in air following the test showed the failure stress of every type of polymer film decreased as a result of irradiation. C1 Boeing Phantom Works, Radiat Effects Lab, Seattle, WA 98124 USA. NASA, Langley Res Ctr, Div Mat, Composites & Polymers Branch, Hampton, VA 23681 USA. Light Technol Inc, Space Radiat Effects Dept, Seattle, WA 98112 USA. RP Russell, DA (reprint author), Boeing Phantom Works, Radiat Effects Lab, MC 2T-50,POB 3999, Seattle, WA 98124 USA. NR 5 TC 4 Z9 4 U1 0 U2 2 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD NOV-DEC PY 2002 VL 39 IS 6 BP 833 EP 838 DI 10.2514/2.3904 PG 6 WC Engineering, Aerospace SC Engineering GA 625FY UT WOS:000179807500004 ER PT J AU Thompson, BF Meek, MC Gold, KL Axelrad, P Born, GH Kubitschek, DG AF Thompson, BF Meek, MC Gold, KL Axelrad, P Born, GH Kubitschek, DG TI Orbit determination for the QuikSCAT spacecraft SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article; Proceedings Paper CT AIAA/ASME/ASCE/AHS/ASC 42nd Structures, Structural Dynamics, and Materials Conference CY APR 16-19, 2001 CL SEATTLE, WASHINGTON SP Amer Inst Aeronaut & Astronaut, ASME, ASCE, AHS, ASC ID SYSTEM AB An operational orbit determination system for QuikSCAT has been developed to meet the requirement for 100-m (3sigma) positioning knowledge. This is nominally accomplished by processing global positioning system (GPS) position solutions in a dynamic filter. The operational orbit determination system produced 24-h overlapping arc position errors between 15 and 25 m (root-sum-square) and 3-h arc overlaps between 5 and 6 m (root-sum-square) for seven-day and one-day arcs, respectively. We also investigated the use of short segments of GPS pseudorange and carrier phase data and obtained results that differ by less than 10 m from the nominal orbit solutions. A third investigation considered the feasibility of a backup orbit determination system using antenna azimuth and elevation angles from three ground tracking stations. The methods and results of processing these three data types are presented. C1 Univ Colorado, Colorado Ctr Astrodynam Res, Boulder, CO 80309 USA. CALTECH, Jet Prop Lab, Opt Navigat Grp, Pasadena, CA 91109 USA. RP Thompson, BF (reprint author), Univ Colorado, Colorado Ctr Astrodynam Res, Campus Box 431, Boulder, CO 80309 USA. NR 8 TC 2 Z9 2 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD NOV-DEC PY 2002 VL 39 IS 6 BP 852 EP 858 DI 10.2514/2.3907 PG 7 WC Engineering, Aerospace SC Engineering GA 625FY UT WOS:000179807500007 ER PT J AU Williams, CH Dudzinski, LA Borowski, SK Juhasz, AJ AF Williams, CH Dudzinski, LA Borowski, SK Juhasz, AJ TI Realizing "2001: A space odyssey": Piloted spherical torus nuclear fusion propulsion SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article; Proceedings Paper CT AIAA/ASME/ASCE/AHS/ASC 42nd Structures, Structural Dynamics, and Materials Conference CY APR 16-19, 2001 CL SEATTLE, WASHINGTON SP Amer Inst Aeronaut & Astronaut, ASME, ASCE, AHS, ASC ID TOKAMAK AB A conceptual vehicle design enabling fast, piloted outer solar system travel was created, predicated on a small aspect ratio spherical torus nuclear fusion reactor. The mission requirements were satisfied by the vehicle concept, which could deliver a 172-t crew payload from Earth to Jupiter rendezvous in 118 days, with an initial mass in low Earth orbit of 1690 t. Engineering conceptual design, analysis, and assessment was performed on all major systems, including artificial gravity payload, central truss, nuclear fusion reactor, power conversion, magnetic nozzle, fast wave plasma heating, tankage, fuel pellet injector, startup/restart fission reactor and battery bank, refrigeration, reaction control, mission design, and space operations. C1 NASA, John H Glenn Res Ctr, Space Transportat Project Off, Adv Concepts Program, Cleveland, OH 44135 USA. NASA, John H Glenn Res Ctr, Power & Board Prop Technol Div, Cleveland, OH 44135 USA. RP Williams, CH (reprint author), NASA, John H Glenn Res Ctr, Space Transportat Project Off, Adv Concepts Program, MS 86-8,21000 Brookpk Rd, Cleveland, OH 44135 USA. NR 40 TC 1 Z9 1 U1 1 U2 3 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD NOV-DEC PY 2002 VL 39 IS 6 BP 874 EP 885 DI 10.2514/2.3894 PG 12 WC Engineering, Aerospace SC Engineering GA 625FY UT WOS:000179807500010 ER PT J AU Mikellides, IG Jongeward, GA Katz, I Manzella, DH AF Mikellides, IG Jongeward, GA Katz, I Manzella, DH TI Plume modeling of stationary plasma thrusters and interactions with the Express-A spacecraft SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article; Proceedings Paper CT AIAA/ASME/ASCE/AHS/ASC 42nd Structures, Structural Dynamics, and Materials Conference CY APR 16-19, 2001 CL SEATTLE, WASHINGTON SP Amer Inst Aeronaut & Astronaut, ASME, ASCE, AHS, ASC AB Hall-effect thruster flight measurements are compared with results from two-dimensional plume and three-dimensional spacecraft interactions computer simulations. The measurements were acquired onboard Express-A 2 and A 3, two Russian communications satellites in geosynchronus orbit. The spacecraft carry four propulsion units for east-west and north-south station keeping. Each unit consists of two stationary plasma thrusters. Ion flux and energy spectra were recorded at various positions with respect to the thrusters and are compared with results from simulations using a uniform electron temperature, two-dimensional plume code that computes the expansion of the main ion beam by a fluid approach. The dynamics of the charge-exchange plasma are determined by a particle-in-cell method. Comparisons suggest good agreement for plume angles less than 40 deg and electron temperature between 8 and 11 eV At approximately 4 and 9 m away from the thruster, and at plume angles less than 10 deg, the discrepancy between measured and computed values is found to be less than 10%. At larger angles, ion flux measurements exhibit large variations during operation of the same thruster. At 80 deg and 1.35 m away from the thruster, flux sensors recorded current densities that ranged between 12 and 55 mA/m(2). The two-dimensional code computes 27 mA/m(2) for an anode mass flow rate of 5.3 mg/s at this location. Moments induced on the spacecraft during the operation of each thruster were also recorded by the attitude control system and are compared with results from a three-dimensional spacecraft interactions code. These measurements were taken during rotation of the solar arrays. C1 Sci Applicat Int Corp, Def Technol Grp, San Diego, CA 92121 USA. CALTECH, Jet Prop Lab, Thermal & Prop Engn Sect, Adv Prop Technol Grp, Pasadena, CA 91109 USA. Univ Toledo, Dept Mech Ind & Mfg Engn, Toledo, OH 43606 USA. RP Mikellides, IG (reprint author), Sci Applicat Int Corp, Def Technol Grp, 9455 Towne Ctr Dr,Mail Stop W2076, San Diego, CA 92121 USA. NR 19 TC 9 Z9 9 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD NOV-DEC PY 2002 VL 39 IS 6 BP 894 EP 903 DI 10.2514/2.3896 PG 10 WC Engineering, Aerospace SC Engineering GA 625FY UT WOS:000179807500012 ER PT J AU Evans, RW Garrett, HB AF Evans, RW Garrett, HB TI Modeling Jupiter's internal electrostatic discharge environment SO JOURNAL OF SPACECRAFT AND ROCKETS LA English DT Article; Proceedings Paper CT AIAA/ASME/ASCE/AHS/ASC 42nd Structures, Structural Dynamics, and Materials Conference CY APR 16-19, 2001 CL SEATTLE, WASHINGTON SP Amer Inst Aeronaut & Astronaut, ASME, ASCE, AHS, ASC AB A method is provided for determining the internal electrostatic discharge environment of Jupiter for future Jovian missions. Jupiter's severe radiation environment is believed to have caused at least 42 internal electrostatic discharge events during the Voyager I flyby. A set of simple tools is presented that allows estimates of the peak electron fluxes and mission fluences for both circular orbits and for equatorial flyby missions with a factor of 2-3 variation. These tools are based on the Divine-Garrett model (Divine, T. N., and Garrett, H. B., "Charged Particle Distributions in Jupiter's Magnetosphere," Journal of Geophysical Research, Vol. 88, No. A9,1983, pp. 6889-6903) and recent data from the Galileo mission. Sample applications are presented. C1 Gibbel Corp, Montrose, CA 91020 USA. CALTECH, Jet Prop Lab, Reliabil Engn Off, Pasadena, CA 91109 USA. RP Evans, RW (reprint author), Gibbel Corp, 2550 Honolulu Blvd,Suite 102, Montrose, CA 91020 USA. NR 22 TC 1 Z9 1 U1 0 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0022-4650 J9 J SPACECRAFT ROCKETS JI J. Spacecr. Rockets PD NOV-DEC PY 2002 VL 39 IS 6 BP 926 EP 932 DI 10.2514/2.3900 PG 7 WC Engineering, Aerospace SC Engineering GA 625FY UT WOS:000179807500016 ER PT J AU Snell, EH Judge, RA Larson, M van der Woerd, MJ AF Snell, EH Judge, RA Larson, M van der Woerd, MJ TI Seeing the heat - preliminary studies of cryocrystallography using infrared imaging SO JOURNAL OF SYNCHROTRON RADIATION LA English DT Article; Proceedings Paper CT 2nd International Workshop on X-ray Damage to Crystalline Biological Samples CY DEC, 2001 CL CHICAGO, ILLINOIS DE macromolecular cryocrystallography; thermal imaging; infrared camera ID FLASH AB As preparation for an extensive study that aims to image the cryocooling process of macromolecular crystals, the ability to thermally image solid objects and liquids at temperatures far below 273 K is demonstrated. In the case of a large lysozyme crystal (1.0 x 0.7 x 0.2 mm), qualitative measurements show the cooling process to take about 0.6 s with the cooling taking place in a wave starting from the face of the crystal nearest to the origin of the cryostream and ending at the point furthest away from the origin. Annealing of this lysozyme crystal, cooled under good cryoprotectant conditions, shows that cold striations form perpendicular to the cooling stream. These striations become more pronounced after successive annealing. Cryocooling of a non-cryoprotected crystal of glucose isomerase displayed an 'S-shaped' cold front wave travelling across the sample. These preliminary results are qualitative but show the power of infrared imaging as a new tool for fundamental and practical cryocrystallography studies. C1 NASA, George C Marshall Space Flight Ctr, Univ Space Res Assoc, Struct Biol Lab, Huntsville, AL 35812 USA. NASA, George C Marshall Space Flight Ctr, UAH, Struct Biol Lab, Huntsville, AL 35812 USA. IRCamerascom, Acworth, GA 30101 USA. RP Snell, EH (reprint author), NASA, George C Marshall Space Flight Ctr, Univ Space Res Assoc, Struct Biol Lab, Code SD46, Huntsville, AL 35812 USA. NR 13 TC 23 Z9 23 U1 0 U2 2 PU BLACKWELL MUNKSGAARD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0909-0495 J9 J SYNCHROTRON RADIAT JI J. Synchrot. Radiat. PD NOV PY 2002 VL 9 BP 361 EP 367 DI 10.1107/S090904950201453X PN 6 PG 7 WC Instruments & Instrumentation; Optics; Physics, Applied SC Instruments & Instrumentation; Optics; Physics GA 611ZU UT WOS:000179049100007 PM 12409623 ER PT J AU Krohn, MH Hellmann, JR Shelleman, DL Green, DJ Sakoske, GE Salem, JA AF Krohn, MH Hellmann, JR Shelleman, DL Green, DJ Sakoske, GE Salem, JA TI Test methodology for strength testing of soda-lime-silica float glass before and after enameling SO JOURNAL OF TESTING AND EVALUATION LA English DT Article DE biaxial flexure; Weibull statistics; scaling strength data; float glass; ring-on-ring; ball-on-ring ID FRACTURE AB Different biaxial flexure test geometries were investigated to determine the most reliable test for evaluating the strength of float glass specimens before and after enameling. The enameled and unenameled samples were tested using the ring-on-ring (ROR) and ball-on-ring (BOR) strength tests. The strengths of each sample set were analyzed using a conventional two-parameter Weibull analysis. For direct comparison of the data, combined Weibull moduli were calculated for the unenarneled tin side, unenameled air side, and enameled tin side data sets. The principle of independent action (PIA) was assumed to be the appropriate fracture criterion and the data were scaled to determine if discrepancies existed between the different testing methodologies. The scale parameters (sigma(o)) were also calculated for the different test geometries. The results showed that there were no statistical differences between the scaled data. Based on the results it was concluded that the ROR test geometry was the better choice compared to the BOR test geometry because of the larger stressed area. The use of a concentric support ring was also found to be more desirable than a ring on equally spaced balls because of the stress concentrations at the support balls, which can lead to problems. C1 Penn State Univ, Dept Mat Sci & Engn, University Pk, PA 16802 USA. Ferro Corp, Glass Res & Dev, Washington, PA 15301 USA. NASA, Glenn Res Ctr, Life Predict Branch, Cleveland, OH 44135 USA. RP Krohn, MH (reprint author), Penn State Univ, Dept Mat Sci & Engn, University Pk, PA 16802 USA. NR 26 TC 3 Z9 3 U1 0 U2 2 PU AMER SOC TESTING MATERIALS PI W CONSHOHOCKEN PA 100 BARR HARBOR DR, W CONSHOHOCKEN, PA 19428-2959 USA SN 0090-3973 J9 J TEST EVAL JI J. Test. Eval. PD NOV PY 2002 VL 30 IS 6 BP 470 EP 477 PG 8 WC Materials Science, Characterization & Testing SC Materials Science GA 623ZZ UT WOS:000179736000002 ER PT J AU Frendi, A Dorland, WD Maung, T Nesman, T Wang, TS AF Frendi, A Dorland, WD Maung, T Nesman, T Wang, TS TI A jet engine noise measurement and prediction tool SO JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA LA English DT Article ID TURBULENCE AB In this paper, the authors describe an innovative jet engine noise measurement and prediction tool. The tool measures sound-pressure levels and frequency spectra in the far field. In addition, the tool provides predicted results while the measurements are being made. The predictions are based on an existing computational fluid dynamics database coupled to an empirical acoustic radiation model based on the far-field approximation to the Lighthill acoustic analogy. Preliminary tests of this acoustic measurement and prediction tool produced very encouraging results. (C) 2002 Acoustical Society of America. C1 Univ Alabama, Dept Mech & Aerosp Engn, Huntsville, AL 35899 USA. AI Signal Res Inc, Huntsville, AL 35805 USA. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Frendi, A (reprint author), Univ Alabama, Dept Mech & Aerosp Engn, Huntsville, AL 35899 USA. EM frendi@mae.uah.edu NR 22 TC 8 Z9 8 U1 0 U2 2 PU ACOUSTICAL SOC AMER AMER INST PHYSICS PI MELVILLE PA STE 1 NO 1, 2 HUNTINGTON QUADRANGLE, MELVILLE, NY 11747-4502 USA SN 0001-4966 J9 J ACOUST SOC AM JI J. Acoust. Soc. Am. PD NOV PY 2002 VL 112 IS 5 BP 2036 EP 2042 DI 10.1121/1.1506690 PN 1 PG 7 WC Acoustics; Audiology & Speech-Language Pathology SC Acoustics; Audiology & Speech-Language Pathology GA 608WG UT WOS:000178870100029 PM 12430815 ER PT J AU Berrios, DC Cucina, RJ Fagan, LM AF Berrios, DC Cucina, RJ Fagan, LM TI Methods for semi-automated indexing for high precision information retrieval SO JOURNAL OF THE AMERICAN MEDICAL INFORMATICS ASSOCIATION LA English DT Article ID CLINICAL QUESTIONS; NEEDS; CARE AB Objective. To evaluate a new system, ISAID (Internet-based Semi-automated Indexing of Documents), and to generate textbook indexes that are more detailed and more useful to readers. Design. Pilot evaluation: simple, nonrandomized trial comparing ISAID with manual indexing methods. Methods evaluation: randomized, cross-over trial comparing three versions of ISAID and usability survey. Participants. Pilot evaluation: two physicians. Methods evaluation: twelve physicians, each of whom used three different versions of the system for a total of 36 indexing sessions. Measurements. Total index term tuples generated per document per minute (TPM), with and without adjustment for concordance with other subjects; inter-indexer consistency; ratings of the usability of the ISAID indexing system. Results. Compared with manual methods, ISAID decreased indexing times greatly Using three versions of ISAID, inter-indexer consistency ranged from 15% to 65% with a mean of 41%, 31%, and 40% for each of three documents. Subjects using the full version of ISAID were faster (average TPM: 5.6) and had higher rates of concordant index generation. There were substantial learning effects, despite our use of a training/run-in phase. Subjects using the full version of ISAID were much faster by the third indexing session (average TPM: 9.1). There was a statistically significant increase in three-subject concordant indexing rate using the full version of ISAID during the second indexing session (p < 0.05). Summary. Users of the ISAID indexing system create complex, precise, and accurate indexing for full-text documents much faster than users of manual methods. Furthermore, the natural language processing methods that ISAID uses to suggest indexes contributes substantially to increased indexing speed and accuracy. C1 Stanford Univ, Stanford, CA 94305 USA. RP Berrios, DC (reprint author), NASA, Ames Res Ctr, Adv Comp Sci Res Inst, MailStop 269-2, Moffett Field, CA 94035 USA. NR 31 TC 10 Z9 10 U1 0 U2 4 PU HANLEY & BELFUS INC PI PHILADELPHIA PA 210 S 13TH ST, PHILADELPHIA, PA 19107 USA SN 1067-5027 J9 J AM MED INFORM ASSN JI J. Am. Med. Inf. Assoc. PD NOV-DEC PY 2002 VL 9 IS 6 BP 637 EP 652 DI 10.1197/jamia.M1075 PG 16 WC Computer Science, Information Systems; Computer Science, Interdisciplinary Applications; Information Science & Library Science; Medical Informatics SC Computer Science; Information Science & Library Science; Medical Informatics GA 609PP UT WOS:000178914400007 PM 12386114 ER PT J AU Lenert, LA Burstin, H Connell, L Gosbee, J Phillips, G AF Lenert, LA Burstin, H Connell, L Gosbee, J Phillips, G TI Federal patient safety initiatives panel summary SO JOURNAL OF THE AMERICAN MEDICAL INFORMATICS ASSOCIATION LA English DT Editorial Material C1 Univ Calif San Diego, San Diego, CA 92103 USA. Agcy Healthcare Res & Qual, Rockville, MD USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Dept Vet Affairs Natl Ctr Patient Safety, Ann Arbor, MI USA. US FDA, Rockville, MD 20857 USA. RP Lenert, LA (reprint author), Univ Calif San Diego, San Diego, CA 92103 USA. NR 3 TC 3 Z9 3 U1 0 U2 0 PU HANLEY & BELFUS INC PI PHILADELPHIA PA 210 S 13TH ST, PHILADELPHIA, PA 19107 USA SN 1067-5027 J9 J AM MED INFORM ASSN JI J. Am. Med. Inf. Assoc. PD NOV-DEC PY 2002 VL 9 IS 6 SU S BP S8 EP S10 DI 10.1197/jamia.M1217 PG 3 WC Computer Science, Information Systems; Computer Science, Interdisciplinary Applications; Information Science & Library Science; Medical Informatics SC Computer Science; Information Science & Library Science; Medical Informatics GA 611FK UT WOS:000179005600003 PM 12386172 ER PT J AU Bacmeister, JT Suarez, MJ AF Bacmeister, JT Suarez, MJ TI Wind stress simulations and the equatorial momentum budget in an AGCM SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID INDUCED TROPICAL CIRCULATION; ATMOSPHERE MODEL; SEASONAL CYCLE; VARIABILITY; RELEVANCE AB A detailed examination of the atmospheric momentum budget over the equatorial Pacific and its relation to oceanic wind stresses is undertaken using the results of a 20-yr (1979-99), forced-SST, AGCM experiment. The results show that free-tropospheric pressure gradients play a significant role in forcing boundary layer flow in the model. In particular, the time-mean and interannual variability of wind stress at the surface is found to be dominated by forcing from the free troposphere. The NCEP reanalyses from 1979-99 are also examined and a similar result is found, although the relative importance of this free-tropospheric forcing is somewhat higher in the model. The seasonal cycle of free-tropospheric forcing in the model is found to be substantially stronger in the model than in the reanalysis, and that has a clearly negative impact on the simulated seasonal cycle of surface wind stresses. In the model, these free-tropospheric pressure gradients are not balanced by turbulent stresses or other dissipative forces. Rather, the momentum budget analysis shows that they are balanced by advective momentum tendencies, with vertical advection of momentum in the descending branch of the Walker circulation playing an important role. C1 NASA, Goddard Space Flight Ctr, Seasonal Interannual Predict Project, Greenbelt, MD 20771 USA. Univ Maryland, Goddard Earth Sci & Technol Ctr, Baltimore, MD 21201 USA. RP Bacmeister, JT (reprint author), NASA, Goddard Space Flight Ctr, Seasonal Interannual Predict Project, Code 913, Greenbelt, MD 20771 USA. NR 26 TC 22 Z9 22 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 NOV PY 2002 VL 59 IS 21 BP 3051 EP 3073 DI 10.1175/1520-0469(2002)059<3051:WSSATE>2.0.CO;2 PG 23 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 603TP UT WOS:000178576500004 ER PT J AU Hwang, HH Meyyappan, M Mathad, GS Ranade, R AF Hwang, HH Meyyappan, M Mathad, GS Ranade, R TI Simulations and experiments of etching of silicon in HBr plasmas for high aspect ratio features SO JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B LA English DT Article ID FEATURE PROFILE EVOLUTION; LEVEL SET METHOD; CL-2; BROMINE; SCATTERING; CL+; SI AB Etching in semiconductor processing typically involves using halides because of the relatively fast rates. Bromine-containing plasmas can generate high aspect ratio trenches, desirable for dynamic random access memory and microelectromechanical system applications, with relatively straight sidewalls. We present scanning electron microscope images for silicon-etched trenches in a HBr plasma. Using a feature profile simulation, we show that the removal yield parameter, or number of neutrals removed per incident ion due to all processes (sputtering, spontaneous desorption, etc.), dictates the profile shape. We find that the profile becomes pinched off when the removal yield is a constant, with a maximum aspect ratio (AR) of about 5 to 1 (depth to height). When the removal yield decreases with increasing ion angle, the etch rate increases at the corners and the trench bottom broadens. The profiles have ARs of over 9:1 for yields that vary with ion angle. To match the experimentally observed etched time of 250 s for an AR, of 9:1 with a trench width of 0.135 mum, we find that the neutral flux must be 3.336 X 10(17) cm(2) s(-1). (C) 2002 American Vacuum Society. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Infineon Technol Inc, Hopewell Jct, NY 12533 USA. RP Hwang, HH (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 16 TC 16 Z9 16 U1 2 U2 7 PU A V S AMER INST PHYSICS PI MELVILLE PA STE 1 NO 1, 2 HUNTINGTON QUADRANGLE,, MELVILLE, NY 11747-4502 USA SN 1071-1023 J9 J VAC SCI TECHNOL B JI J. Vac. Sci. Technol. B PD NOV-DEC PY 2002 VL 20 IS 6 BP 2199 EP 2205 DI 10.1116/1.1513621 PG 7 WC Engineering, Electrical & Electronic; Nanoscience & Nanotechnology; Physics, Applied SC Engineering; Science & Technology - Other Topics; Physics GA 633WJ UT WOS:000180307300004 ER PT J AU Dempsey, PJ Morales, W Afjeh, AA AF Dempsey, PJ Morales, W Afjeh, AA TI Investigation of spur gear fatigue damage using wear debris SO LUBRICATION ENGINEERING LA English DT Article DE spur gears; wear particles; fatigue; fuzzy logic; health monitoring AB A new diagnostic for detecting and assessing surface fatigue damage to spur gears was developed. This diagnostic tool was evaluated by analyzing metallic oil wear debris generated during fatigue tests that were performed using a spur gearbox rig. During each test, readings from an on-line oil debris sensor were monitored and recorded for assessment of gear pitting damage. The debris measured by the oil debris sensor was used to identify ''membership functions'' to build a fuzzy logic model. Using fuzzy logic techniques on the oil debris data. threshold limits were defined that discriminated between different stages of pitting wear. Results showed that oil wear debris data combined with fuzzy logic analysis techniques was a good predictor of pitting damage on spur gears. C1 NASA, Glenn Res Ctr, Cleveland, OH USA. Univ Toledo, Toledo, OH 43606 USA. RP Dempsey, PJ (reprint author), NASA, Glenn Res Ctr, Cleveland, OH USA. NR 17 TC 4 Z9 4 U1 0 U2 0 PU SOC TRIBOLOGISTS & LUBRICATION ENGINEERS PI PARK RIDGE PA 840 BUSSE HIGHWAY, PARK RIDGE, IL 60068 USA SN 0024-7154 J9 LUBR ENG JI Lubric. Eng. PD NOV PY 2002 VL 58 IS 11 BP 18 EP 22 PG 5 WC Engineering, Mechanical SC Engineering GA 617RP UT WOS:000179374900009 ER PT J AU Fisher, TH Chao, P Upton, CG Day, AJ AF Fisher, TH Chao, P Upton, CG Day, AJ TI A C-13 NMR study of the methylol derivatives of 2,4 '- and 4,4 '-dihydroxydiphenylmethanes found in resol phenol-formaldehyde resins SO MAGNETIC RESONANCE IN CHEMISTRY LA English DT Article DE NMR; H-1 NMR; C-13 NMR; phenol-formaldehyde resins; dihydroxydiphenylmethanes ID SPECTROSCOPY AB A total of 13 of the 16 possible methylol derivatives of 2,4'- and 4,4'-dihydroxydiphenylmethane have been synthesized, isolated, and identified. These compounds are found as intermediates in the cure process of resol phenol-formaldehyde (PF) resins. Analysis of the C-13 NMR spectra (in acetone-d(6)) of these compounds provided a way to evaluate the seven methylolphenol ring types (methylol derivatives of 2-hydroxyphenyl and 4-hydroxyphenyl rings) found in typical resol PF resins using the ipso carbon region from 150 to 160 ppm. A simple diagnostic test was developed using the chemical shift values of the methylol methylene carbon atoms to identify the presence of intermediates containing either a 2-hydroxyphenyl or a 4-hydroxyphenyl ring. Using these data it is now possible to analyze the major components in extracted prepreg PF resins. Copyright (C) 2002 John Wiley Sons, Ltd. C1 Mississippi State Univ, Dept Chem, Mississippi State, MS 39762 USA. San Fu Chem Co, Taipei, Taiwan. NASA, George C Marshall Space Flight Ctr, FD 21, Huntsville, AL 35812 USA. ATK Thiokol Prop, Huntsville, AL 35812 USA. RP Fisher, TH (reprint author), Mississippi State Univ, Dept Chem, Mail Stop 9573, Mississippi State, MS 39762 USA. NR 15 TC 9 Z9 9 U1 0 U2 2 PU JOHN WILEY & SONS LTD PI W SUSSEX PA BAFFINS LANE CHICHESTER, W SUSSEX PO19 1UD, ENGLAND SN 0749-1581 J9 MAGN RESON CHEM JI Magn. Reson. Chem. PD NOV PY 2002 VL 40 IS 11 BP 747 EP 751 DI 10.1002/mrc.1089 PG 5 WC Chemistry, Multidisciplinary; Chemistry, Physical; Spectroscopy SC Chemistry; Spectroscopy GA 607XP UT WOS:000178816300011 ER PT J AU Venneri, SL Noor, AK AF Venneri, SL Noor, AK TI Plenty of room in the air SO MECHANICAL ENGINEERING LA English DT Article C1 NASA, Washington, DC 20546 USA. Old Dominion Univ, Ctr Adv Engn Environm, Norfolk, VA USA. Univ Florida, Gainesville, FL 32611 USA. RP Venneri, SL (reprint author), NASA, Washington, DC 20546 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ASME-AMER SOC MECHANICAL ENG PI NEW YORK PA THREE PARK AVE, NEW YORK, NY 10016-5990 USA SN 0025-6501 J9 MECH ENG JI Mech. Eng. PD NOV PY 2002 VL 124 IS 11 BP 42 EP 48 PG 7 WC Engineering, Mechanical SC Engineering GA 610HJ UT WOS:000178954400026 ER PT J AU Chambers, JE Cassen, P AF Chambers, JE Cassen, P TI The effects of nebula surface density profile and giant-planet eccentricities on planetary accretion in the inner solar system SO METEORITICS & PLANETARY SCIENCE LA English DT Article ID TERRESTRIAL PLANETS; ASTEROID BELT; EMBRYOS; TIMESCALES; EVOLUTION; BODIES; GROWTH; MODEL; DISK; GAS AB We describe results of 32 N-body planetary accretion simulations that investigate the dependence of terrestrial-planet formation on nebula surface density profile sigma and evolution of the eccentricities of Jupiter and Saturn e(J,S). Two surface density profiles are examined: a decaying profile with a proportional to 1/a, Where a is orbital semi-major axis, and a peaked profile in which a increases for a < 2 AU and decreases for a > 2 AU. The peaked profiles are generated by models of coagulation in an initially hot nebula. Models with initial e(J,S) = 0.05 (the current value) and 0.1 are considered. Simulations using the decaying profile with e(J,S) = 0.1 produce systems most like the observed planets in terms of mass-weighted mean a and the absence of a planet in the asteroid belt. Simulations with doubled a produce planets roughly twice as massive as the nominal case. Most initial embryos are removed in each simulation via ejection from the solar system or collision with the Sun. The asteroid belt is almost entirely cleared on a timescale of 10-100 Ma that depends sensitively on e(J,S). Most initial mass with a < 2 AU survives, with the degree of mass loss increasing with a. Mass loss from the terrestrial region occurs on a timescale that is long compared to the mass loss time for the asteroid belt. Substantial radial mixing of material occurs in all simulations, but is greater in simulations with initital e(J,S) = 0.05. The degree of mixing is equivalent to a feeding zone of half width 1.5 and 0.9 AU for an Earth mass planet at 1 AU for the cases e(J,S) = 0.05 and 0.1, respectively. In simulations with e(J,S) = 0.05, roughly one-third and 5-10% of the mass contained in final terrestrial planets originated in the region a > 2.5 AU for the decaying and peaked profiles, respectively. In the case e(J,S) = 0.1, the median mass accreted from a > 2.5 AU is zero for both profiles. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. SETI Inst, Mt View, CA 94043 USA. RP Chambers, JE (reprint author), NASA, Ames Res Ctr, Mail Stop 245-3, Moffett Field, CA 94035 USA. NR 29 TC 50 Z9 50 U1 0 U2 1 PU METEORITICAL SOC PI FAYETTEVILLE PA DEPT CHEMISTRY/BIOCHEMISTRY, UNIV ARKANSAS, FAYETTEVILLE, AR 72701 USA SN 1086-9379 J9 METEORIT PLANET SCI JI Meteorit. Planet. Sci. PD NOV PY 2002 VL 37 IS 11 BP 1523 EP 1540 PG 18 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 620FU UT WOS:000179524000004 ER PT J AU Nuth, JA Rietmeijer, FJM Hill, HGM AF Nuth, JA Rietmeijer, FJM Hill, HGM TI Condensation processes in astrophysical environments: The composition and structure of cometary grains SO METEORITICS & PLANETARY SCIENCE LA English DT Article ID INTERSTELLAR SILICATE MINERALOGY; MIDINFRARED SPECTRAL EVOLUTION; HERBIG AE/BE SYSTEMS; SOLAR NEBULA; CIRCUMSTELLAR DISKS; MAGNESIUM SILICATES; CRYSTALLINE OLIVINE; SOLID CONDENSATION; DUST; SMOKES AB We review the results of our recent experimental studies of astrophysical dust analogs. We discuss the condensation of amorphous silicates from mixed metal vapors, including evidence that such condensates form with metastable eutectic compositions. We consider the spectral evolution of amorphous magnesium silicate condensates as a function of time and temperature. Magnesium silicate smokes anneal readily at temperatures of about 1000-1100 K. In contrast we find that iron silicates require much higher temperatures (similar to1300 K) to bring about similar changes on the same timescale (days to months). We first apply these results to infrared space observatory observations of crystalline magnesium silicate grains around high-mass-outflow asymptotic giant branch stars in order to demonstrate their general utility in a rather simple environment. Finally, we apply these experimental results to infrared observations of comets and protostars in order to derive some interesting conclusions regarding large-scale nebular dynamics, the natural production of organic molecules in protostellar nebulae, and the use of crystalline magnesium silicates as a relative indicator of a comet's formation age. C1 NASA, Goddard Space Flight Ctr, Astrochem Branch, Greenbelt, MD 20771 USA. Univ New Mexico, Dept Earth & Planetary Sci, Albuquerque, NM 87131 USA. RP Nuth, JA (reprint author), NASA, Goddard Space Flight Ctr, Astrochem Branch, Code 691, Greenbelt, MD 20771 USA. EM nuth@gsfc.nasa.gov RI Nuth, Joseph/E-7085-2012 NR 54 TC 69 Z9 69 U1 1 U2 4 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 1086-9379 J9 METEORIT PLANET SCI JI Meteorit. Planet. Sci. PD NOV PY 2002 VL 37 IS 11 BP 1579 EP 1590 PG 12 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 620FU UT WOS:000179524000008 ER PT J AU Kim, K Park, S Lee, JB Manohara, H Desta, Y Murphy, M Ahn, CH AF Kim, K Park, S Lee, JB Manohara, H Desta, Y Murphy, M Ahn, CH TI Rapid replication of polymeric and metallic high aspect ratio microstructures using PDMS and LIGA technology SO MICROSYSTEM TECHNOLOGIES LA English DT Article; Proceedings Paper CT 4th International Workshop on High Aspect Ratio Microstructure Technology (HARMST 2001) CY JUN, 2001 CL CHIB, JAPAN ID FABRICATION; POLYDIMETHYLSILOXANE AB This paper present a method of rapid replication of polymeric high aspect ratio microstructures (HARMs) and a method of rapid reproduction of metallic micromold inserts for HARMs using polydimethylsiloxane (PDMS) casting and standard LIGA processes. A high aspect ratio (HAR) metallic micromold insert, featuring a variety of test microstructures made of electroplated nickel with 15:1 height-to-width ratio for 300 pm microstructures, was fabricated by the standard LIGA process using deep X-ray lithography (DXRL). A 10:1 mixture of pre-polymer PDMS and a curing agent were cast onto the HAR metallic micromold insert, cured and peeled off to create reverse images of the HAR metallic micromold insert in PDMS. In addition to the replication of polymeric HARMs, replicated PDMS HARMS were coated with a metallic sacrificial layer and electroplated in nickel to reproduce another metallic micromold insert. This method can be used to rapidly and massively reproduce HAR metallic micromold inserts in low cost mass production manner without further using DXRL. C1 Univ Texas, Dept Elect Engn, Richardson, TX 75083 USA. Louisiana State Univ, Dept Elect & Comp Engn, Baton Rouge, LA 70803 USA. Louisiana State Univ, Dept Mech Engn, Baton Rouge, LA 70803 USA. Louisiana State Univ, Ctr Adv Microstruct & Devices, Baton Rouge, LA 70803 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Cincinnati, Dept Elect & Comp Engn & Comp Sci, Cincinnati, OH 45221 USA. RP Kim, K (reprint author), Univ Texas, Dept Elect Engn, Richardson, TX 75083 USA. NR 11 TC 69 Z9 70 U1 2 U2 28 PU SPRINGER-VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0946-7076 J9 MICROSYST TECHNOL JI Microsyst. Technol. PD NOV PY 2002 VL 9 IS 1-2 BP 5 EP 10 DI 10.1007/s00542-002-0194-6 PG 6 WC Engineering, Electrical & Electronic; Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Physics, Applied SC Engineering; Science & Technology - Other Topics; Materials Science; Physics GA 627HY UT WOS:000179928800002 ER PT J AU Sams, CF Nelman-Gonzalez, M Alexander, M Adams, CL AF Sams, CF Nelman-Gonzalez, M Alexander, M Adams, CL TI Inhibition of polarization and signal integration in human T cells in response to contact-mediated stimulation during suspension. SO MOLECULAR BIOLOGY OF THE CELL LA English DT Meeting Abstract CT 42nd Annual Meeting of the American-Society-for-Cell-Biology CY DEC 14-18, 2002 CL SAN FRANCISCO, CALIFORNIA SP Amer Soc Cell Biol C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. Wyle Life Sci, Houston, TX USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER SOC CELL BIOLOGY PI BETHESDA PA 8120 WOODMONT AVE, STE 750, BETHESDA, MD 20814-2755 USA SN 1059-1524 J9 MOL BIOL CELL JI Mol. Biol. Cell PD NOV PY 2002 VL 13 MA 853 BP 153A EP 153A PG 1 WC Cell Biology SC Cell Biology GA 621BR UT WOS:000179569100852 ER PT J AU Conley, CA Winfree, S AF Conley, CA Winfree, S TI Elucidation of a Leiomodin's biochemical function SO MOLECULAR BIOLOGY OF THE CELL LA English DT Meeting Abstract CT 42nd Annual Meeting of the American-Society-for-Cell-Biology CY DEC 14-18, 2002 CL SAN FRANCISCO, CALIFORNIA SP Amer Soc Cell Biol C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER SOC CELL BIOLOGY PI BETHESDA PA 8120 WOODMONT AVE, STE 750, BETHESDA, MD 20814-2755 USA SN 1059-1524 J9 MOL BIOL CELL JI Mol. Biol. Cell PD NOV PY 2002 VL 13 MA 1763 BP 313A EP 313A PG 1 WC Cell Biology SC Cell Biology GA 621BR UT WOS:000179569101762 ER PT J AU Winfree, S Reinsch, SS AF Winfree, S Reinsch, SS TI The role of XCTK1 kinesin-like protein in early Xenopus laevis embryogenesis SO MOLECULAR BIOLOGY OF THE CELL LA English DT Meeting Abstract CT 42nd Annual Meeting of the American-Society-for-Cell-Biology CY DEC 14-18, 2002 CL SAN FRANCISCO, CALIFORNIA SP Amer Soc Cell Biol C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Lockheed Martin Inc, Moffett Field, CA USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER SOC CELL BIOLOGY PI BETHESDA PA 8120 WOODMONT AVE, STE 750, BETHESDA, MD 20814-2755 USA SN 1059-1524 J9 MOL BIOL CELL JI Mol. Biol. Cell PD NOV PY 2002 VL 13 MA 1822 BP 324A EP 324A PG 1 WC Cell Biology SC Cell Biology GA 621BR UT WOS:000179569101821 ER PT J AU Reinsch, SS Conway, GC AF Reinsch, SS Conway, GC TI The zebrafish G12 gene is required for nuclear positioning and cell migrations during early development SO MOLECULAR BIOLOGY OF THE CELL LA English DT Meeting Abstract CT 42nd Annual Meeting of the American-Society-for-Cell-Biology CY DEC 14-18, 2002 CL SAN FRANCISCO, CALIFORNIA SP Amer Soc Cell Biol C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER SOC CELL BIOLOGY PI BETHESDA PA 8120 WOODMONT AVE, STE 750, BETHESDA, MD 20814-2755 USA SN 1059-1524 J9 MOL BIOL CELL JI Mol. Biol. Cell PD NOV PY 2002 VL 13 MA 2645 BP 470A EP 470A PG 1 WC Cell Biology SC Cell Biology GA 621BR UT WOS:000179569102644 ER PT J AU Searby, ND Steele, CR Almeida, EA Globus, RK AF Searby, ND Steele, CR Almeida, EA Globus, RK TI Dynamics of mechanical strain-induced shape changes in living confluent osteoblasts SO MOLECULAR BIOLOGY OF THE CELL LA English DT Meeting Abstract CT 42nd Annual Meeting of the American-Society-for-Cell-Biology CY DEC 14-18, 2002 CL SAN FRANCISCO, CALIFORNIA SP Amer Soc Cell Biol C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Stanford Univ, Stanford, CA 94305 USA. Univ Calif San Francisco, San Francisco, CA 94143 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER SOC CELL BIOLOGY PI BETHESDA PA 8120 WOODMONT AVE, STE 750, BETHESDA, MD 20814-2755 USA SN 1059-1524 J9 MOL BIOL CELL JI Mol. Biol. Cell PD NOV PY 2002 VL 13 MA 2683 BP 476A EP 476A PG 1 WC Cell Biology SC Cell Biology GA 621BR UT WOS:000179569102682 ER PT J AU Quezada, MET Nguyen, M Li, E Gennuso, S Spencer, D Wang, E Reinsch, SS AF Quezada, MET Nguyen, M Li, E Gennuso, S Spencer, D Wang, E Reinsch, SS TI Insertional mutagenesis screen for genes involved in otic/vestibular development and function in Xenopus tropicalis SO MOLECULAR BIOLOGY OF THE CELL LA English DT Meeting Abstract CT 42nd Annual Meeting of the American-Society-for-Cell-Biology CY DEC 14-18, 2002 CL SAN FRANCISCO, CALIFORNIA SP Amer Soc Cell Biol C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. CNR, Washington, DC 20418 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER SOC CELL BIOLOGY PI BETHESDA PA 8120 WOODMONT AVE, STE 750, BETHESDA, MD 20814-2755 USA SN 1059-1524 J9 MOL BIOL CELL JI Mol. Biol. Cell PD NOV PY 2002 VL 13 MA 2979 BP 529A EP 529A PG 1 WC Cell Biology SC Cell Biology GA 621BR UT WOS:000179569102978 ER PT J AU Lupo, PJ Kamal, E Gonda, SR AF Lupo, PJ Kamal, E Gonda, SR TI Gene expression profiling of Human Renal Cortical Epithelial Cells at three stages of tissue engineering in the Hydrodynamic Focusing Bioreactor (HFB) SO MOLECULAR BIOLOGY OF THE CELL LA English DT Meeting Abstract CT 42nd Annual Meeting of the American-Society-for-Cell-Biology CY DEC 14-18, 2002 CL SAN FRANCISCO, CALIFORNIA SP Amer Soc Cell Biol C1 NASA, Lyndon B Johnson Space Ctr, Biol Syst Off, Houston, TX 77058 USA. Wyle Labs, Houston, TX USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER SOC CELL BIOLOGY PI BETHESDA PA 8120 WOODMONT AVE, STE 750, BETHESDA, MD 20814-2755 USA SN 1059-1524 J9 MOL BIOL CELL JI Mol. Biol. Cell PD NOV PY 2002 VL 13 MA 3070 BP 545A EP 545A PG 1 WC Cell Biology SC Cell Biology GA 621BR UT WOS:000179569103069 ER PT J AU Vander Auwera, J El Hachtouki, R Brown, LR AF Vander Auwera, J El Hachtouki, R Brown, LR TI Absolute line wavenumbers in the near infrared: (C2H2)-C-12 and (CO2)-C-12-O-16 SO MOLECULAR PHYSICS LA English DT Article; Proceedings Paper CT 17th International Conference on High Resolution Molecular Spectroscopy CY SEP 09-13, 2001 CL NIJMEGEN, NETHERLANDS ID MU-M; ENERGY-LEVELS; FREQUENCY MEASUREMENTS; ACETYLENE; SPECTRUM; BAND; LASER; SPECTROSCOPY; TRANSITIONS; INTENSITIES AB 40 absolute line wavenumbers in the 3nu(3) band of (CO2)-C-12-O-16 between 6927 cm-(1) and 6989 cm-(1) and 626 absolute line wavenumbers in the near infrared absorption spectrum of (C2H2)-C-12 between 7060 cm-(1) and 9900 cm-(1) have been measured using high resolution Fourier transform spectroscopy. The calibration of the CO2 line wavenumbers relied on heterodyne frequencies available in the nu(1) + nu(3) band of (C2H2)-C-12 near 6556 cm-(1). The absolute uncertainty of the calibrated CO2 line wavenumbers is estimated to 0.000 08 cm-(1). The acetylene spectra were calibrated using heterodyne frequencies available in the 2-0 band of (CO)-C-12-O-16 and the line wavenumbers obtained in the 3nu(3) band of (CO2)-C-12-O-16. The absolute uncertainty of the calibrated acetylene line wavenumbers is estimated to range from 0.0003 cm-(1) to 0.006 cm-(1) for strong to very weak isolated lines. Comparison with absolute line wavenumbers obtained independently at JPL in the 3nu(3) band of (C2H2)-C-12 near 9649 cm-(1), calibrated using absolute wavenumbers available in the 2-0 and 3-0 (near 6350 cm-(1)) bands of (CO)-C-12-O-16, shows very good agreement. Also, the vibration-rotation constants for the observed upper vibrational states of (C2H2)-C-12 were determined, but without accounting for the perturbations affecting these states. C1 Free Univ Brussels, B-1050 Brussels, Belgium. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Fonds Natl Rech Sci, B-1050 Brussels, Belgium. RP Vander Auwera, J (reprint author), Free Univ Brussels, Lab Chim Phys Mol CP 160-09,50 Ave FD Roosevelt, B-1050 Brussels, Belgium. NR 33 TC 19 Z9 19 U1 0 U2 4 PU TAYLOR & FRANCIS LTD PI ABINGDON PA 4 PARK SQUARE, MILTON PARK,, ABINGDON OX14 4RN, OXON, ENGLAND SN 0026-8976 J9 MOL PHYS JI Mol. Phys. PD NOV PY 2002 VL 100 IS 22 BP 3563 EP 3576 DI 10.1080/00268970210162880 PG 14 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 622TU UT WOS:000179663800012 ER PT J AU Williams, DR Mathioudakis, M Gallagher, PT Phillips, KJH McAteer, RTJ Keenan, FP Rudawy, P Katsiyannis, AC AF Williams, DR Mathioudakis, M Gallagher, PT Phillips, KJH McAteer, RTJ Keenan, FP Rudawy, P Katsiyannis, AC TI An observational study of a magneto-acoustic wave in the solar corona SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE MHD; waves; eclipses; Sun : activity; Sun : corona; Sun : oscillations ID EMISSION-LINES; OSCILLATIONS; ECLIPSE; LOOPS AB The Solar Eclipse Corona Imaging System (SECIS) observed a strong 6-s oscillation in an active region coronal loop, during the 1999 August 11 total solar eclipse. In the present paper we show that this oscillation is associated with a fast-mode magneto-acoustic wave that travels through the loop apex with a velocity of 2100 km s(-1). We use near-simultaneous SOHO observations to calculate the parameters of the loop and its surroundings such as density, temperature and their spatial variation. We find that the temporal evolution of the intensity is in agreement with the model of an impulsively generated, fast-mode wave. C1 Queens Univ Belfast, Dept Pure & Appl Phys, Belfast BT7 1NN, Antrim, North Ireland. UCL, Mullard Space Sci Lab, Dorking RH5 6NT, Surrey, England. Rutherford Appleton Lab, Space Sci & Technol Dept, Didcot OX11 0QX, Oxon, England. NASA, Goddard Space Flight Ctr, L3 Com Analyt Corp, Greenbelt, MD 20771 USA. Univ Wroclaw, Astron Inst, PL-50138 Wroclaw, Poland. RP Williams, DR (reprint author), Queens Univ Belfast, Dept Pure & Appl Phys, Belfast BT7 1NN, Antrim, North Ireland. EM drw@mssl.ucl.ac.uk RI McAteer, R. T. James/D-3736-2011; Williams, David/E-6676-2011; Katsiyannis, Thanassis/L-8496-2013; Gallagher, Peter/C-7717-2011 OI Williams, David/0000-0001-9922-8117; Gallagher, Peter/0000-0001-9745-0400 NR 13 TC 71 Z9 71 U1 0 U2 3 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD NOV 1 PY 2002 VL 336 IS 3 BP 747 EP 752 DI 10.1046/j.1365-8711.2002.05764.x PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 608RK UT WOS:000178860300009 ER PT J AU Heidelberg, JF Paulsen, IT Nelson, KE Gaidos, EJ Nelson, WC Read, TD Eisen, JA Seshadri, R Ward, N Methe, B Clayton, RA Meyer, T Tsapin, A Scott, J Beanan, M Brinkac, L Daugherty, S DeBoy, RT Dodson, RJ Durkin, AS Haft, DH Kolonay, JF Madupu, R Peterson, JD Umayam, LA White, O Wolf, AM Vamathevan, J Weidman, J Impraim, M Lee, K Berry, K Lee, C Mueller, J Khouri, H Gill, J Utterback, TR McDonald, LA Feldblyum, TV Smith, HO Venter, JC Nealson, KH Fraser, CM AF Heidelberg, JF Paulsen, IT Nelson, KE Gaidos, EJ Nelson, WC Read, TD Eisen, JA Seshadri, R Ward, N Methe, B Clayton, RA Meyer, T Tsapin, A Scott, J Beanan, M Brinkac, L Daugherty, S DeBoy, RT Dodson, RJ Durkin, AS Haft, DH Kolonay, JF Madupu, R Peterson, JD Umayam, LA White, O Wolf, AM Vamathevan, J Weidman, J Impraim, M Lee, K Berry, K Lee, C Mueller, J Khouri, H Gill, J Utterback, TR McDonald, LA Feldblyum, TV Smith, HO Venter, JC Nealson, KH Fraser, CM TI Genome sequence of the dissimilatory metal ion-reducing bacterium Shewanella oneidensis SO NATURE BIOTECHNOLOGY LA English DT Article ID MANNOSE-SENSITIVE HEMAGGLUTININ; PUTREFACIENS MR-1; ESCHERICHIA-COLI; VIBRIO-CHOLERAE; OUTER-MEMBRANE; BIOFILM FORMATION; DNA-POLYMERASE; REDUCTION; MANGANESE; IDENTIFICATION AB Shewanella oneidensis is an important model organism for bioremediation studies because of its diverse respiratory capabilities, conferred in part by multicomponent, branched electron transport systems. Here we report the sequencing of the S. oneidensis genome, which consists of a 4,969,803-base pair circular chromosome with 4,758 predicted protein-encoding open reading frames (CDS) and a 161,613-base pair plasmid with 173 CDSs. We identified the first Shewanella lambda-like phage, providing a potential tool for further genome engineering. Genome analysis revealed 39 c-type cytochromes, including 32 previously unidentified in S. oneidensis, and a novel periplasmic [Fe] hydrogenase, which are integral members of the electron transport system. This genome sequence represents a critical step in the elucidation of the pathways for reduction (and bioremediation) of pollutants such as uranium (U) and chromium (Cr), and offers a starting point for defining this organism's complex electron transport systems and metal ion-reducing capabilities. C1 Inst Genom Res, Rockville, MD 20850 USA. Univ Maryland, Ctr Marine Biotechnol, Baltimore, MD 21202 USA. Johns Hopkins Univ, Baltimore, MD 21218 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Arizona, Dept Biochem & Mol Biophys, Tucson, AZ 85721 USA. Carnegie Inst Washington, Geophys Lab, Washington, DC 20015 USA. George Washington Univ, Med Ctr, Washington, DC 20037 USA. RP Fraser, CM (reprint author), Inst Genom Res, 9712 Med Ctr Dr, Rockville, MD 20850 USA. RI Read, Timothy/E-6240-2011; Paulsen, Ian/K-3832-2012; Nelson, William/E-9263-2016; OI Paulsen, Ian/0000-0001-9015-9418; Nelson, William/0000-0002-1873-3929; Mueller, Jacob L./0000-0003-1232-0303; Heidelberg, John/0000-0003-0673-3224; Fraser, Claire/0000-0003-1462-2428; Eisen, Jonathan A./0000-0002-0159-2197; Vamathevan, Jessica/0000-0003-2016-9754 NR 41 TC 459 Z9 1128 U1 10 U2 137 PU NATURE AMERICA INC PI NEW YORK PA 345 PARK AVE SOUTH, NEW YORK, NY 10010-1707 USA SN 1087-0156 J9 NAT BIOTECHNOL JI Nat. Biotechnol. PD NOV PY 2002 VL 20 IS 11 BP 1118 EP 1123 DI 10.1038/nbt749 PG 6 WC Biotechnology & Applied Microbiology SC Biotechnology & Applied Microbiology GA 611WV UT WOS:000179041500022 PM 12368813 ER PT J AU Hedges, SB AF Hedges, SB TI The origin and evolution of model organisms SO NATURE REVIEWS GENETICS LA English DT Review ID EARLIEST LAND PLANTS; MOLECULAR EVIDENCE; PHYLOGENETIC CLASSIFICATION; DIVERGENCE TIMES; COMMON ANCESTOR; UNIVERSAL TREE; RIBOSOMAL-RNA; RED ALGAE; DATA SETS; EUKARYOTES AB The phylogeny and timescale of life are becoming better understood as the analysis of genomic data from model organisms continues to grow. As a result, discoveries are being made about the early history of life and the origin and development of complex multicellular life. This emerging comparative framework and the emphasis on historical patterns is helping to bridge barriers among organism-based research communities. C1 Penn State Univ, NASA, Astrobiol Inst, University Pk, PA 16802 USA. Penn State Univ, Dept Biol, Mueller Lab 208, University Pk, PA 16802 USA. RP Hedges, SB (reprint author), Penn State Univ, NASA, Astrobiol Inst, University Pk, PA 16802 USA. NR 126 TC 458 Z9 479 U1 11 U2 174 PU NATURE PUBLISHING GROUP PI LONDON PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 1471-0056 J9 NAT REV GENET JI Nat. Rev. Genet. PD NOV PY 2002 VL 3 IS 11 BP 838 EP 849 DI 10.1038/nrg929 PG 12 WC Genetics & Heredity SC Genetics & Heredity GA 611WW UT WOS:000179041600012 PM 12415314 ER PT J AU Bunge, SA Hazeltine, E Scanlon, MD Rosen, AC Gabrieli, JDE AF Bunge, SA Hazeltine, E Scanlon, MD Rosen, AC Gabrieli, JDE TI Dissociable contributions of prefrontal and parietal cortices to response selection SO NEUROIMAGE LA English DT Article ID POSITRON EMISSION TOMOGRAPHY; ANTERIOR CINGULATE CORTEX; VERBAL WORKING-MEMORY; FUNCTIONAL MRI; COGNITIVE CONTROL; RHESUS-MONKEY; MOTOR ATTENTION; BRAIN ACTIVITY; ACTIVATION; TASK AB The ability to select between possible responses to a given situation is central to human cognition. The goal of this study was to distinguish between brain areas representing candidate responses and areas selecting between competing response alternatives. Event-related fMRI data were acquired while 10 healthy adults performed a task used to examine response competition: the Eriksen flanker task. Left parietal cortex was activated by either of two manipulations that increased the need to maintain a representation of possible responses. In contrast, lateral prefrontal. and rostral anterior cingulate cortices were specifically engaged by the need to select among competing response alternatives. These findings support the idea that parietal cortex is involved in activating possible responses on the basis of learned stimulus-response associations, and that prefrontal. cortex is recruited when there is a need to select between competing responses. (C) 2002 Elsevier Science (USA). C1 Stanford Univ, Program Neurosci, Stanford, CA 94305 USA. NASA, Washington, DC 20546 USA. Stanford Univ, Dept Psychol, Stanford, CA 94305 USA. RP Bunge, SA (reprint author), MIT, Dept Brain & Cognit Sci, 77 Massachusetts Ave,NE20-351, Cambridge, MA 02139 USA. FU NIA NIH HHS [F32 AG005865, F32 AG005865-03]; NIMH NIH HHS [MH61426] NR 76 TC 323 Z9 326 U1 0 U2 20 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 1053-8119 J9 NEUROIMAGE JI Neuroimage PD NOV PY 2002 VL 17 IS 3 BP 1562 EP 1571 DI 10.1006/nimg.2002.1252 PG 10 WC Neurosciences; Neuroimaging; Radiology, Nuclear Medicine & Medical Imaging SC Neurosciences & Neurology; Radiology, Nuclear Medicine & Medical Imaging GA 611JG UT WOS:000179012800043 PM 12414294 ER PT J AU Davis, MW Olla, BL AF Davis, MW Olla, BL TI Mortality of lingcod towed in a net as related to fish length, seawater temperature, and air exposure: A laboratory bycatch study SO NORTH AMERICAN JOURNAL OF FISHERIES MANAGEMENT LA English DT Article ID WALLEYE POLLOCK; OTTER-TRAWL; SURVIVAL; SABLEFISH; CAUGHT; CONCORDANCE; STRESS; LIGHT; SEA AB The mortality of discarded bycatch is a critical problem in the management of fisheries worldwide. Little is known about the key principles involved in the mortality of discarded bycatch. These principles are best elaborated under controlled conditions in the laboratory where the actions and interactions of stressors found in fishing practices can be investigated independently. The goal of this study was to investigate the principles involved in the mortality of lingcod Ophiodon elongatus by testing hypotheses concerning the factors that may control trawl bycatch mortality. Lingcod were towed in a net and exposed to increased seawater temperature and to air, two stressors that occur during the processes of trawl capture, retrieval through a thermocline, and landing on deck. Mortality occurred after exposure to more than 45 min in air, after exposure to 4 h towing in a net followed by more than 30 min in air, or after 4 h towing followed by exposure to seawater above 16.0degreesC for 30 min and air for 15 min. In treatments of equal stressor intensity, smaller fish (41-51 cm total length) had higher rates of mortality than larger fish (52-67 cm). The effects of net towing and air-as well as of towing, increased seawater temperature, and air-were additive. Lingcod bycatch mortality may be reduced by decreasing trawling times and exposure to increased seawater and air temperatures during warmer seasons or by restricting fisheries that produce bycatch to seasons of cooler temperatures. The sorting, handling, and release of bycatch on deck after capture may be conducted in a manner that would probably enhance survival if fish are released within 30 min of capture. Because smaller lingcod had higher rates of mortality, further information about the mortality rates of relevant size-classes of fish is needed to validate the assumptions of management rules for released, undersized bycatch that are designed to enhance recruitment. C1 Natl Marine Fisheries Serv, Hatfield Marine Sci Ctr, Alaska Fisheries Sci Ctr, Newport, OR 97365 USA. Oregon State Univ, Hatfield Marine Sci Ctr, Newport, OR 97365 USA. RP Davis, MW (reprint author), Natl Marine Fisheries Serv, Hatfield Marine Sci Ctr, Alaska Fisheries Sci Ctr, Newport, OR 97365 USA. NR 37 TC 25 Z9 25 U1 0 U2 5 PU AMER FISHERIES SOC PI BETHESDA PA 5410 GROSVENOR LANE SUITE 110, BETHESDA, MD 20814-2199 USA SN 0275-5947 J9 N AM J FISH MANAGE JI North Am. J. Fish Manage. PD NOV PY 2002 VL 22 IS 4 BP 1095 EP 1104 DI 10.1577/1548-8675(2002)022<1095:MOLTIA>2.0.CO;2 PG 10 WC Fisheries SC Fisheries GA 622MP UT WOS:000179651100003 ER PT J AU Jones, AL DeYoung, RJ Elsayed-All, HE AF Jones, AL DeYoung, RJ Elsayed-All, HE TI Compact solid-state dye polymer laser for ozone lidar applications SO OPTICAL ENGINEERING LA English DT Article DE solid-state dye lasers; lasers for lidar; narrowband laser oscillator ID PERFORMANCE AB A solid-state dye laser for potential application as an ozone lidar transmitter is described. The solid-state dye laser material is made from a polymer host polymethyl methacrylate (PMMA) injected with a pyrromethene laser dye PM-597. The laser oscillator cavity is end-pumped by a Q-switched Nd:YAG laser at 532 nm. Broadband and narrowband laser oscillator cavities were constructed and tested. For the broadband oscillator, slope efficiency as high as 79% was achieved. A narrowband laser oscillator was constructed to generate radiation at 578 and 600 nm with 390-pm linewidth, This output was frequency doubled to 289 or 300 nm using a beta-barium borate (BBO) crystal. The oscillator cavity generated a maximum energy of 11 mJ at 578 nm when pumped by 100 mJ, 532 nm, at 10-Hz repetition rate. Maximum output energy of 380 muJ was achieved at a wavelength of 289 nm. (C) 2002 Society of Photo-Optical Instrumentation Engineers. C1 Old Dominion Univ, Dept Elect & Comp Engn, Norfolk, VA 23529 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Jones, AL (reprint author), Old Dominion Univ, Dept Elect & Comp Engn, Norfolk, VA 23529 USA. NR 20 TC 6 Z9 6 U1 0 U2 1 PU SPIE-INT SOCIETY OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98225 USA SN 0091-3286 J9 OPT ENG JI Opt. Eng. PD NOV PY 2002 VL 41 IS 11 BP 2951 EP 2958 DI 10.1117/1.1511244 PG 8 WC Optics SC Optics GA 614ZH UT WOS:000179221000035 ER PT J AU DiRienzi, J Drachman, RJ AF DiRienzi, J Drachman, RJ TI D-wave resonances in positronium hydride SO PHYSICAL REVIEW A LA English DT Article ID SCATTERING; HYDROGEN; STATES AB In a previous paper [Phys. Rev. A 65, 032721 (2002)] we reexamined a model describing the structure of the low-energy Ps-H resonances as being due to quasibound states of the positron in the perturbed Coulomb potential of the H- ion appearing in the closed, rearranged channel. In particular, we wished to understand why the lowest p-state resonance was so far away from the lowest quasibound (2p) state. We found that the lowest resonance actually corresponds to the first-excited [3p] state, while the lowest state is not recognizable as a resonance. In the present work we repeat our analysis, but this time for the lowest d state. We find that the lowest [3d] state does correspond to a resonance shifted moderately. C1 Coll Notre Dame Maryland, Baltimore, MD 21210 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP DiRienzi, J (reprint author), Coll Notre Dame Maryland, Baltimore, MD 21210 USA. NR 13 TC 11 Z9 11 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 NOV PY 2002 VL 66 IS 5 AR 054702 DI 10.1103/PhysRevA.66.054702 PG 4 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 622DU UT WOS:000179631900145 ER PT J AU Liu, HL Charbonneau, P Pouquet, A Bogdan, T McIntosh, S AF Liu, HL Charbonneau, P Pouquet, A Bogdan, T McIntosh, S TI Continuum analysis of an avalanche model for solar flares SO PHYSICAL REVIEW E LA English DT Article ID DIMENSIONAL MAGNETOHYDRODYNAMIC TURBULENCE; SELF-ORGANIZED CRITICALITY; DRIVEN DISSIPATIVE SYSTEMS; EQUATIONS; CORONA; FLUID AB We investigate the continuum limit of a class of self-organized critical lattice models for solar flares. Such models differ from the classical numerical sandpile model in their formulation of stability criteria in terms of the curvature of the nodal field, and are known to belong to a different universality class. A fourth-order nonlinear hyperdiffusion equation is reverse engineered from the discrete model's redistribution rule. A dynamical renormalization-group analysis of the equation yields scaling exponents that compare favorably with those measured in the discrete lattice model within the relevant spectral range dictated by the sizes of the domain and the lattice grid. We argue that the fourth-order nonlinear diffusion equation that models the behavior of the discrete model in the continuum limit is, in fact, compatible with magnetohydrodynamics (MHD) of the flaring phenomenon in the regime of strong magnetic field and the effective magnetic diffusivity characteristic of strong MHD turbulence. C1 Natl Ctr Atmospher Res, High Altitude Observ, Boulder, CO 80307 USA. Natl Ctr Atmospher Res, Adv Study Program, Boulder, CO 80307 USA. NASA, Goddard Space Flight Ctr, ESA Res & Sci Support Dept, Greenbelt, MD 20771 USA. RP Natl Ctr Atmospher Res, High Altitude Observ, POB 3000, Boulder, CO 80307 USA. RI Liu, Han-Li/A-9549-2008 OI Liu, Han-Li/0000-0002-6370-0704 NR 34 TC 13 Z9 13 U1 0 U2 0 PU AMER PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 2470-0045 EI 2470-0053 J9 PHYS REV E JI Phys. Rev. E PD NOV PY 2002 VL 66 IS 5 AR 056111 DI 10.1103/PhysRevE.66.056111 PG 10 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA 622DG UT WOS:000179630800108 PM 12513560 ER PT J AU Manceau, R Carlson, JR Gatski, TB AF Manceau, R Carlson, JR Gatski, TB TI A rescaled elliptic relaxation approach: Neutralizing the effect on the log layer SO PHYSICS OF FLUIDS LA English DT Article ID TURBULENT CHANNEL FLOW; NEAR-WALL TURBULENCE; BOUNDARY-LAYERS; HEAT-TRANSFER; MODEL; SIMULATION AB An alternative scaling for the relaxation function describing the velocity pressure-gradient correlation used in the elliptic relaxation procedure for both eddy-viscosity and Reynolds stress models is presented. While other alternatives have been proposed to neutralize the adverse effect on log-layer dynamics, they have relied on altering the original differential formulation. A simpler alternative is presented here that involves a rescaling of the relaxation function with the isotropic dissipation rate as well as the turbulent kinetic energy. Various comparative tests are made and the new rescaled formulation is shown to provide improved and accurate predictions for both the eddy-viscosity and Reynolds stress models. (C) 2002 American Institute of Physics. C1 Univ Poiters, CNRS, UMR 6609, Lab Etud Aerodynam,SP2MI, F-86962 Futuroscope, France. NASA, Langley Res Ctr, Computat Modeling & Simulat Branch, Hampton, VA 23681 USA. RP Manceau, R (reprint author), Univ Poiters, CNRS, UMR 6609, Lab Etud Aerodynam,SP2MI, Teleport 2,Bd Marie & Pierre Curie,BP 30179, F-86962 Futuroscope, France. RI Manceau, Remi/B-3943-2012; OI Manceau, Remi/0000-0002-3964-161X NR 21 TC 13 Z9 13 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 1070-6631 J9 PHYS FLUIDS JI Phys. Fluids PD NOV PY 2002 VL 14 IS 11 BP 3868 EP 3879 DI 10.1063/1.1511547 PG 12 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA 603AQ UT WOS:000178537000015 ER PT J AU Rao, MVVS Sharma, SP Meyyappan, M AF Rao, MVVS Sharma, SP Meyyappan, M TI Mass spectrometric measurements in inductively coupled CF4/Ar plasmas SO PLASMA SOURCES SCIENCE & TECHNOLOGY LA English DT Article ID LASER-INDUCED FLUORESCENCE; ENERGY DISTRIBUTION FUNCTION; LANGMUIR PROBE MEASUREMENTS; NEGATIVE-ION DENSITIES; LOW-PRESSURE; ABSORPTION-SPECTROSCOPY; FLUOROCARBON PLASMAS; ETCHING PLASMAS; POSITIVE-IONS; ELECTRON AB Positive ion fluxes, mean ion energies and ion energy distribution functions in low pressure CF4/Ar plasmas have been measured. The experiments were conducted in a Gaseous Electronics Conference cell using an inductively coupled plasma device powered by a 13.56 MHz radiofrequency (rf) power source. The measurements were made at 200 and 300 W of input rf power and at 10, 20, 30 and 50 mTorr gas pressures for three gas mixtures: (i) 20% CF4: 80% Ar, (ii) 50% CF4: 50% Ar and (iii) 80% CF4: 20% Ar. A Langmuir probe was also used to measure plasma parameters such as n(e), n(i)(+) and electron energy distribution functions (EEDF) which were subsequently used to reconcile the mass spectrometer data. CF3+ is the most dominant fluorocarbon ion product of the plasma, followed by CF2+ and CF+. Ar+ is also detected in significant amounts with its relative flux increasing with the increase in Ar content in the gas mixture. Significant amounts of etch products, SiFx+/COFx+(x=0-3), of the quartz window were also detected. The fluorocarbon ions are produced by direct electron impact and by ion-molecule reactions between Ar+ and CF4 as well as between CF3+ and CF4. However, the concentrations of CF2+ and CF+ are much larger than that which can be possibly produced from these two processes. The available cross-section data Suggest that the direct electron impact ionization of the fragment neutrals and negative ion production by electron attachment may be responsible for the increase in the concentrations of the minor ions. F- densities, estimated by using the measured EEDF and positive ion flux data and the available cross-section data, agree well with the published experimental data. C1 NASA, Plasma Res Lab, Ames Res Ctr, Moffett Field, CA 94035 USA. NASA, ELORET, Ames Res Ctr, Moffett Field, CA USA. RP Sharma, SP (reprint author), NASA, Plasma Res Lab, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 57 TC 9 Z9 9 U1 0 U2 3 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0963-0252 J9 PLASMA SOURCES SCI T JI Plasma Sources Sci. Technol. PD NOV PY 2002 VL 11 IS 4 BP 397 EP 406 AR PII S0963-0252(02)52557-3 DI 10.1088/0963-0252/11/4/306 PG 10 WC Physics, Fluids & Plasmas SC Physics GA 628WA UT WOS:000180018500006 ER PT J AU De Lorimier, RM Smith, JJ Dwyer, MA Looger, LL Sali, KM Paavola, CD Rizk, SS Sadigov, S Conrad, DW Loew, L Hellinga, HW AF De Lorimier, RM Smith, JJ Dwyer, MA Looger, LL Sali, KM Paavola, CD Rizk, SS Sadigov, S Conrad, DW Loew, L Hellinga, HW TI Construction of a fluorescent biosensor family SO PROTEIN SCIENCE LA English DT Article DE periplasmic binding proteins; biosensor; conformational change; fluorescence, ratiometry; bioinformatics ID MALTOSE-BINDING PROTEIN; TRANSPORT CHEMOSENSORY RECEPTOR; GENETICALLY-ENGINEERED PROTEIN; ESCHERICHIA-COLI K-12; ACTIVE-TRANSPORT; LIGAND-BINDING; HAEMOPHILUS-INFLUENZAE; NUCLEOTIDE-SEQUENCE; CRYSTAL-STRUCTURE; SALMONELLA-TYPHIMURIUM AB Bacterial periplasmic binding proteins (bPBPs) are specific for a wide variety of small molecule ligands. bPBPs undergo a large, ligand-mediated conformational change that can be linked to reporter functions to monitor ligand concentrations. This mechanism provides the basis of a general system for engineering families of reagentless biosensors that share a common physical signal transduction functionality and detect many different analytes. We demonstrate the facility of designing optical biosensors based on fluorophore conjugates using 8 environmentally sensitive fluorophores and 11 bPBPs specific for diverse ligands, including sugars, amino acids, anions, cations, and dipeptides. Construction of reagentless fluorescent biosensors relies on identification of sites that undergo a local conformational change in concert with the global, ligand-mediated hinge-bending motion. Construction of cysteine mutations at these locations then permits site-specific coupling of environmentally sensitive fluorophores that report ligand binding as changes in fluorescence intensity. For 10 of the bPBPs presented in this study, the three-dimensional receptor structure was used to predict the location of reporter sites. In one case, a bPBP sensor specific for glutamic and aspartic acid was designed starting from genome sequence information and illustrates the potential for discovering novel binding functions in the microbial genosphere using bioinformatics. C1 Duke Univ, Med Ctr, Dept Biochem, Durham, NC 27710 USA. Univ Connecticut, Ctr Hlth, Dept Physiol, Farmington, CT 06030 USA. Univ Connecticut, Ctr Hlth, Ctr Biomed Imaging Technol, Farmington, CT 06030 USA. NASA, Ames Res Ctr, Astrobiol Technol Branch, Moffett Field, CA 94035 USA. RP Hellinga, HW (reprint author), Duke Univ, Med Ctr, Dept Biochem, Box 3711, Durham, NC 27710 USA. EM hwh@biochem.duke.edu OI Loew, Leslie/0000-0002-1851-4646 NR 90 TC 181 Z9 183 U1 1 U2 18 PU WILEY-BLACKWELL PI MALDEN PA COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA SN 0961-8368 J9 PROTEIN SCI JI Protein Sci. PD NOV PY 2002 VL 11 IS 11 BP 2655 EP 2675 DI 10.1110/ps.021860 PG 21 WC Biochemistry & Molecular Biology SC Biochemistry & Molecular Biology GA 606NG UT WOS:000178739600013 PM 12381848 ER PT J AU Herbst, W Hamilton, CM Vrba, FJ Ibrahimov, MA Bailer-Jones, CAL Mundt, R Lamm, M Mazeh, T Webster, ZT Haisch, KE Williams, EC Rhodes, AH Balonek, TJ Scholz, A Riffeser, A AF Herbst, W Hamilton, CM Vrba, FJ Ibrahimov, MA Bailer-Jones, CAL Mundt, R Lamm, M Mazeh, T Webster, ZT Haisch, KE Williams, EC Rhodes, AH Balonek, TJ Scholz, A Riffeser, A TI Fine structure in the circumstellar environment of a young, solar-like star: The unique eclipses of KH 15D SO PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF THE PACIFIC LA English DT Letter ID ORION NEBULA CLUSTER; ROTATION; NGC-2264; PLANETS AB Results of an international campaign to photometrically monitor the unique pre-main-sequence eclipsing object KH 15D are reported. An updated ephemeris for the eclipse is derived that incorporates a slightly revised period of 48.36 days. There is some evidence that the orbital period is actually twice that value, with two eclipses occurring per cycle. The extraordinary depth (similar to3.5 mag) and duration (similar to18 days) of the eclipse indicate that it is caused by circumstellar matter, presumably the inner portion of a disk. The eclipse has continued to lengthen with time, and the central brightness reversals are not as extreme as they once were. V-R and V-I colors indicate that the system is slightly bluer near minimum light. Ingress and egress are remarkably well modeled by the passage of a knife edge across a limb-darkened star. Possible models for the system are briefly discussed. C1 Wesleyan Univ, Dept Astron, Middletown, CT 06459 USA. US Naval Observ, Flagstaff Stn, Flagstaff, AZ 86002 USA. Uzbek Acad Sci, Ulugh Beg Astron Inst, Tashkent 700052, Uzbekistan. Max Planck Inst Astron, D-69117 Heidelberg, Germany. Tel Aviv Univ, Sch Phys & Astron, Raymond & Beverly Sackler Fac Exact Sci, IL-69978 Tel Aviv, Israel. Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Wesleyan Univ, Dept Astron, Middletown, CT 06459 USA. Colgate Univ, Dept Phys & Astron, Hamilton, NY 13346 USA. Thuringer Landessternwarte Tautenburg, D-07778 Tautenburg, Germany. Univ Sternwarte, D-81679 Munich, Germany. RP Herbst, W (reprint author), Wesleyan Univ, Dept Astron, Middletown, CT 06459 USA. NR 17 TC 52 Z9 52 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-6280 J9 PUBL ASTRON SOC PAC JI Publ. Astron. Soc. Pac. PD NOV PY 2002 VL 114 IS 801 BP 1167 EP 1172 DI 10.1086/344205 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 610QP UT WOS:000178972200001 ER PT J AU Durante, M George, K Wu, H Cucinotta, FA AF Durante, M George, K Wu, H Cucinotta, FA TI Karyotypes of human lymphocytes exposed to high-energy iron ions SO RADIATION RESEARCH LA English DT Article ID IN-SITU HYBRIDIZATION; TRUE INCOMPLETE EXCHANGES; TELOMERIC PNA PROBE; INDUCED CHROMOSOMAL-ABERRATIONS; INDUCED STRUCTURAL-ABERRATIONS; DNA CONTENT; HIGH-LET; CHARGED-PARTICLES; COMPLEX EXCHANGES; ALPHA-PARTICLES AB Chromosomal aberrations were analyzed using multicolor fluorescence in situ hybridization (mFISH) in human peripheral blood lymphocytes after in vitro exposure to gamma rays or accelerated Fe-56 ions (1 GeV/nucleon, 145 keV/mum) at Brookhaven National Laboratory (Upton, NY). Doses of 0.3 and 3 Gy were used for both radiation types. Chromosomes were prematurely condensed by a phosphatase inhibitor (calyculin A) to avoid the population selection bias observed at metaphase as a result of the severe cell cycle delays induced by heavy ions. A total of 1053 karyotypes (G(2) and M phases) were analyzed in irradiated lymphocytes. Results revealed different distribution patterns for chromosomal aberrations after low- and high-LET radiation exposures: Heavy ions induced a much higher fraction of cells with multiple aberrations, while the majority of the aberrant cells induced by low doses of gamma rays contained a single aberration. The high fraction of complex-type exchanges after heavy ions leads to an overestimation of simple-type asymmetrical interchanges (dicentrics) from analysis of Giemsa-stained samples. However, even after a dose of 3 Gy iron ions, about 30% of the cells presented no complex-type exchanges. The involvement of individual chromosomes in exchanges was similar for densely and sparsely ionizing radiation, and no statistically significant evidence of a nonrandom involvement of specific chromosomes was detected. (C) 2002 by Radiation Research Society. C1 NASA, Lyndon B Johnson Space Ctr, Radiat Hlth Off, Houston, TX 77058 USA. Univ Naples Federico II, Dipartimento Sci Fis, Naples, Italy. Wyle labs, Houston, TX USA. RP Cucinotta, FA (reprint author), NASA, Lyndon B Johnson Space Ctr, Radiat Hlth Off, Mail Code SF21, Houston, TX 77058 USA. RI Durante, Marco/K-1315-2014; OI Durante, Marco/0000-0002-4615-553X NR 45 TC 77 Z9 81 U1 0 U2 3 PU RADIATION RESEARCH SOC PI OAK BROOK PA 820 JORIE BOULEVARD, OAK BROOK, IL 60523 USA SN 0033-7587 J9 RADIAT RES JI Radiat. Res. PD NOV PY 2002 VL 158 IS 5 BP 581 EP 590 DI 10.1667/0033-7587(2002)158[0581:KOHLET]2.0.CO;2 PG 10 WC Biology; Biophysics; Radiology, Nuclear Medicine & Medical Imaging SC Life Sciences & Biomedicine - Other Topics; Biophysics; Radiology, Nuclear Medicine & Medical Imaging GA 612RR UT WOS:000179089700004 PM 12385635 ER PT J AU Byun, SH Hajj, GA Young, LE AF Byun, SH Hajj, GA Young, LE TI Development and application of GPS signal multipath simulator SO RADIO SCIENCE LA English DT Article DE GPS signals; multipath; reflection; diffraction; Geometrical Theory of Diffraction (GTD) AB [1] A ray tracing GPS signal multipath simulator which takes into account the signal reflection and diffraction from surrounding objects has been developed. By properly modeling the environment around an antenna and the GPS receiver's tracking loop, this simulator can assess the GPS signal multipath error. Thus, it can be used in the early design phase of an experiment to foretell hazardous environmental configurations that can cause severe multipath. It can also aid in finding the best antenna type, location, and orientation within a given environment, and provides a quantitative estimate of multipath errors on GPS measurements. The capability of the simulator is demonstrated by using the International Space Station (ISS) environment. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP CALTECH, Jet Prop Lab, Mail Stop 238-600,4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM sung.byun@jpl.nasa.gov; george.hajj@jpl.nasa.gov; lawrence.e.young@jpl.nasa.gov NR 30 TC 17 Z9 17 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0048-6604 EI 1944-799X J9 RADIO SCI JI Radio Sci. PD NOV PY 2002 VL 37 IS 6 AR 1098 DI 10.1029/2001RS002549 PG 23 WC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications SC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications GA 635MA UT WOS:000180402000010 ER PT J AU Justice, CO Townshend, JRG Vermote, EF Masuoka, E Wolfe, RE Saleous, N Roy, DP Morisette, JT AF Justice, CO Townshend, JRG Vermote, EF Masuoka, E Wolfe, RE Saleous, N Roy, DP Morisette, JT TI An overview of MODIS Land data processing and product status SO REMOTE SENSING OF ENVIRONMENT LA English DT Article ID HIGH-RESOLUTION RADIOMETER; DATA SET; AVHRR; PARAMETERS; PROGRAM; SYSTEM; EARTH AB Data from the first Moderate Resolution Imaging Spectroradiometer (MODIS) instrument on the NASA Terra Platform are being used to provide a new generation of land data products in support of the National Aeronautics and Space Administration (NASA)'s Earth Science Enterprise, global change research and natural resource management. The MODIS products include global data sets heretofore unavailable, derived from new moderate resolution spectral bands with spatial resolutions of 250 m to 1 km. A partnership between Science Team members and the MODIS Science Data Support Team is producing data sets of unprecedented volume and number for the land research and applications. This overview paper provides a summary of the instrument performance and status, the data production system, the products, their status and availability for land studies. (C) 2002 Elsevier Science Inc. All rights reserved. C1 Univ Maryland, Dept Geog, College Pk, MD 20742 USA. Univ Maryland, Inst Adv Comp Studies, College Pk, MD 20742 USA. NASA, Goddard Space Flight Ctr, Terr Informat Syst Branch, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Biospher Sci Branch, Greenbelt, MD 20771 USA. Raytheon Co, ITSS, Lanham, MD 20706 USA. RP Justice, CO (reprint author), Univ Maryland, Dept Geog, 2181 LeFrak Hall, College Pk, MD 20742 USA. RI Wolfe, Robert/E-1485-2012; Vermote, Eric/K-3733-2012 OI Wolfe, Robert/0000-0002-0915-1855; NR 46 TC 467 Z9 503 U1 6 U2 62 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD NOV PY 2002 VL 83 IS 1-2 BP 3 EP 15 AR PII S0034-4257(02)00084-6 DI 10.1016/S0034-4257(02)00084-6 PG 13 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA 613YW UT WOS:000179160200002 ER PT J AU Guenther, B Xiong, X Salomonson, VV Barnes, WL Young, J AF Guenther, B Xiong, X Salomonson, VV Barnes, WL Young, J TI On-orbit performance of the Earth Observing System Moderate Resolution Imaging Spectroradiometer; first year of data SO REMOTE SENSING OF ENVIRONMENT LA English DT Article ID CALIBRATION; EOS-AM1; MODIS AB The Moderate Resolution Imaging Spectroradiometer (MODIS) completed the first year of science data acquisition on February 24, 2000. The overall performance of the sensor and the on-board calibration systems for this first year have been very good. Several features of the performance lead to characteristics in the data set that merit special attention. These items are sometimes called data product caveats, and are described here. Uncertainty budgets for the 0.555-mum band, the 1.240-mum band and the 12.000-mum band are presented at several days throughout this first year. The uncertainty is estimated to be decreasing with time during this period, and to be near 1.8% in reflectance factor for 0.555 mum, 1.9% for the reflectance factor product for the 1.240 mum band, and 0.7% for the 12.000-mum band at nadir at the end of the first year. Degradation of the solar diffuser is 2.3% at 0.412 mum, known to an uncertainty of +/-0.5%. Solar diffuser degradation for wavelengths longer that 0.5 mum is indistinguishable from the uncertainty in trend determination for the first year. Mirror side degradation at 0.412 mum is 6 +/- 0.5%, with a mirror side difference of an additional 3%. The performance present in the data at the end of year 1 provides significant encouragement that many improvements in our understanding of the Earth system performance can and will be based on MODIS data during the coming years. (C) 2002 Published by Elsevier Science Inc. C1 Raytheon Co, Santa Barbara Remote Sensing, Goleta, CA 93117 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Sci Syst Applicat Inc, Seabrook, MD 20706 USA. RP Guenther, B (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 9 TC 98 Z9 106 U1 0 U2 6 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD NOV PY 2002 VL 83 IS 1-2 BP 16 EP 30 AR PII S0034-4257(02)00097-4 DI 10.1016/S0034-4257(02)00097-4 PG 15 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA 613YW UT WOS:000179160200003 ER PT J AU Wolfe, RE Nishihama, M Fleig, AJ Kuyper, JA Roy, DP Storey, JC Patt, FS AF Wolfe, RE Nishihama, M Fleig, AJ Kuyper, JA Roy, DP Storey, JC Patt, FS TI Achieving sub-pixel geolocation accuracy in support of MODIS land science SO REMOTE SENSING OF ENVIRONMENT LA English DT Article ID IMAGING SPECTRORADIOMETER MODIS; GEOMETRIC CORRECTION; MISREGISTRATION; NAVIGATION; INSTRUMENT; IMPACT; EARTH AB The Moderate Resolution Imaging Spectroradiometer (MODIS) was launched in December 1999 on the polar orbiting Terra spacecraft and since February 2000 has been acquiring daily global data in 36 spectral bands-29 with 1 km, five with 500 m, and two with 250 m nadir pixel dimensions. The Terra satellite has on-board exterior orientation (position and attitude) measurement systems designed to enable geolocation of MODIS data to approximately 150 m (1 Q) at nadir. A global network of ground control points is being used to determine biases and trends in the sensor orientation. Biases have been removed by updating models of the spacecraft and instrument orientation in the MODIS geolocation software several times since launch and have improved the MODIS geolocation to approximately 50 m (1sigma) at nadir. This paper overviews the geolocation approach, summarizes the first year of geolocation analysis, and overviews future work. The approach allows an operational characterization of the MODIS geolocation errors and enables individual MODIS observations to be geolocated to the sub-pixel accuracies required for terrestrial global change applications. (C) 2002 Elsevier Science Inc. All rights reserved. C1 NASA, Goddard Space Flight Ctr, Terr Phys Lab, Greenbelt, MD 20771 USA. SAIC GSC, Beltsville, MD 20705 USA. NASA, Goddard Space Flight Ctr, Lab Hydrospher Proc, Greenbelt, MD 20771 USA. US Geol Survey, EROS Data Ctr, Sioux Falls, SD 57198 USA. Univ Maryland, Dept Geog, College Pk, MD 20742 USA. SAIC GSC, Seabrook, MD 20706 USA. PITA Analyt Sci, Bethesda, MD 20817 USA. Raytheon Co, ITSS, Lanham, MD 20706 USA. RP Wolfe, RE (reprint author), NASA, Goddard Space Flight Ctr, Terr Phys Lab, Code 922, Greenbelt, MD 20771 USA. RI Wolfe, Robert/E-1485-2012 OI Wolfe, Robert/0000-0002-0915-1855 NR 34 TC 336 Z9 352 U1 4 U2 35 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD NOV PY 2002 VL 83 IS 1-2 BP 31 EP 49 AR PII S0034-4257(02)00085-8 DI 10.1016/S0034-4257(02)00085-8 PG 19 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA 613YW UT WOS:000179160200004 ER PT J AU Roy, DP Borak, JS Devadiga, S Wolfe, RE Zheng, M Descloitres, J AF Roy, DP Borak, JS Devadiga, S Wolfe, RE Zheng, M Descloitres, J TI The MODIS Land product quality assessment approach SO REMOTE SENSING OF ENVIRONMENT LA English DT Article ID RESOLUTION IMAGING SPECTRORADIOMETER; SURFACE; COVER; EARTH; INDEX AB The correct interpretation of scientific information from global, long-term series of remote sensing products requires the ability to discriminate between product artifacts and changes in the Earth processes being monitored. A suite of global land surface products is made from Moderate Resolution Imaging Spectroradiometer (MODIS) instrument data. Quality assessment (QA) is an integral part of this production chain and focuses on evaluating and documenting the scientific quality of the products with respect to their intended performance. This paper describes the QA approach adopted by the MODIS Land (MODLAND) Science Team and coordinated by the MODIS Land Data Operational Product Evaluation (LDOPE) facility. The described methodology represents a new approach for assessing and ensuring the performance of land remote sensing products that are generated on a systematic basis. (C) 2002 Elsevier Science Inc. All rights reserved. C1 NASA, Goddard Space Flight Ctr, Sci Syst & Applicat Inc, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Raytheon, ITSS, Greenbelt, MD 20771 USA. Univ Maryland, Dept Geog, College Pk, MD 20742 USA. RP Roy, DP (reprint author), NASA, Goddard Space Flight Ctr, Sci Syst & Applicat Inc, Code 922, Greenbelt, MD 20771 USA. RI Wolfe, Robert/E-1485-2012 OI Wolfe, Robert/0000-0002-0915-1855 NR 26 TC 119 Z9 124 U1 1 U2 13 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD NOV PY 2002 VL 83 IS 1-2 BP 62 EP 76 AR PII S0034-4257(02)00087-1 DI 10.1016/S0034-4257(02)00087-1 PG 15 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA 613YW UT WOS:000179160200006 ER PT J AU Morisette, JT Privette, JL Justice, CO AF Morisette, JT Privette, JL Justice, CO TI A framework for the validation of MODIS Land products SO REMOTE SENSING OF ENVIRONMENT LA English DT Article ID NET PRIMARY PRODUCTION; LEAF-AREA INDEX; IGBP DISCOVER; NETWORK; SITES; SURFACE AB The MODIS Land team is producing a suite of global land products whose uncertainty will be estimated through validation activities. The MODIS Land team will base its validation work on the comparison of its products to similar products derived from independent sources. The independent products will be derived from a combination of in situ data and imagery from airborne and spaceborne sensors. Since in situ and image data can often serve to validate more than one product and sensor, the MODIS Land Discipline Team's validation strategy has focused on data collection and analysis at the EOS Land Validation Core Sites. Initial characterization of these sites is presented, as well as an overview of the on-line access to imagery and field data collected over these sites. The data and resources available through this work are available to the science community for continued validation and scientific investigations. This paper describes the results of a 4-year effort to develop the infrastructure to allow timely and comprehensive validation of EOS land products. (C) 2002 Elsevier Science Inc. All rights reserved. C1 NASA, Goddard Space Flight Ctr, Biospher Sci Branch, Greenbelt, MD 20771 USA. Univ Maryland, Dept Geog, College Pk, MD 20742 USA. RP Morisette, JT (reprint author), NASA, Goddard Space Flight Ctr, Biospher Sci Branch, Code 922-923, Greenbelt, MD 20771 USA. RI Privette, Jeffrey/G-7807-2011 OI Privette, Jeffrey/0000-0001-8267-9894 NR 54 TC 159 Z9 173 U1 6 U2 16 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD NOV PY 2002 VL 83 IS 1-2 BP 77 EP 96 AR PII S0034-4257(02)00088-3 DI 10.1016/S0034-4257(02)00088-3 PG 20 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA 613YW UT WOS:000179160200007 ER PT J AU Vermote, EF El Saleous, NZ Justice, CO AF Vermote, EF El Saleous, NZ Justice, CO TI Atmospheric correction of MODIS data in the visible to middle infrared: first results SO REMOTE SENSING OF ENVIRONMENT LA English DT Article ID RESOLUTION IMAGING SPECTRORADIOMETER; LAND; AEROSOL AB The MODIS instrument provides major advances in moderate resolution earth observation. Improved spatial resolution for land observation at 250 and 500 m and improved spectral band placement provide new remote sensing opportunities. NASA has invested in the development of improved algorithms for MODIS, which will provide new data sets for global change research. Surface reflectance is one of the key products from MODIS and is used in developing several higher-order land products. The surface reflectance algorithm builds on the heritage of the Advanced Very High Resolution Radiometer (AVHRR) and SeaWiFS algorithms, taking advantage of the new sensing capabilities of MODIS. Atmospheric correction by the removal of water vapor and aerosol effects provides improvements over previous coarse resolution products and the basis for a new time-series, which will extend through to the NPOESS generation imagers. This paper summarizes the first evaluation of the MODIS surface reflectance product accuracy, in comparison with other data products and in the context of the MODIS instrument performance since launch. The MODIS surface reflectance product will provide an important time-series data set for quantifying global environmental change. (C) 2002 Elsevier Science Inc. All rights reserved. C1 Univ Maryland, Dept Geog, NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Raytheon Co, ITSS, Lexington, MA 02041 USA. RP Vermote, EF (reprint author), Univ Maryland, Dept Geog, NASA, Goddard Space Flight Ctr, Code 923, Greenbelt, MD 20771 USA. RI Fuentes, Marcia/A-4216-2012; Vermote, Eric/K-3733-2012 NR 12 TC 384 Z9 407 U1 3 U2 47 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD NOV PY 2002 VL 83 IS 1-2 BP 97 EP 111 AR PII S0034-4257(02)00089-5 DI 10.1016/S0034-4257(02)00089-5 PG 15 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA 613YW UT WOS:000179160200008 ER PT J AU Petitcolin, F Vermote, E AF Petitcolin, F Vermote, E TI Land surface reflectance, emissivity and temperature from MODIS middle and thermal infrared data SO REMOTE SENSING OF ENVIRONMENT LA English DT Article ID BIDIRECTIONAL REFLECTANCE; AVHRR DATA; MU-M; REGION; REFLECTIVITY; RESOLUTION; ALGORITHM; AEROSOL; MODELS; WINDOW AB The following paper presents a method to retrieve surface reflectance, emissivity and temperature in the middle infrared (3-5 mum) and thermal infrared (8-12 mum). It is applied to Moderate Resolution Imaging Spectroradiometer (MODIS) data acquired over Southern Africa during the August to October 2000 period. This method relies first on atmospheric correction of the middle-thermal infrared radiances which uses National Center for Environmental Prediction (NCEP) humidity, pressure and temperature profiles and second on constructing and using a database of night emissivities ratio (Temperature Independent Spectral Indices of Emissivity, TISIE). The middle infrared reflectances (3-5 pm) are then derived from day-time measurements and mean TISIE values. By hemispheric integration (over a 16-day period), they lead to middle infrared directional emissivity which, combined with TISIE again, leads to thermal infrared emissivity and surface temperature. The reflectance accuracies are assessed by looking at targets of known reflectance (water and sun-glint). The emissivities in the thermal infrared are assessed by checking the spectral invariance of the derived surface temperature in the 3-5- and 8-12-mum region. Other consistency checks are performed leading to the conclusion that the reflectance, emissivity and surface temperature are derived within 0.015, 0.01 and 1 K, respectively. Finally, a direct application of the MODIS middle infrared surface reflectances to the fire detection problem is developed and the results compared to the Landsat 7 high spatial resolution data. (C) 2002 Elsevier Science Inc. All rights reserved. C1 Univ Maryland, Dept Geog, College Pk, MD 20942 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Univ Maryland, Dept Geog, College Pk, MD 20942 USA. EM francois@kratmos.gsfc.nasa.gov; eric@kratmos.gsfc.nasa.gov RI Vermote, Eric/K-3733-2012 NR 30 TC 53 Z9 54 U1 2 U2 15 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0034-4257 EI 1879-0704 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD NOV PY 2002 VL 83 IS 1-2 BP 112 EP 134 AR PII S0034-4257(02)00094-9 DI 10.1016/S0034-4257(02)00094-9 PG 23 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA 613YW UT WOS:000179160200009 ER PT J AU Schaaf, CB Gao, F Strahler, AH Lucht, W Li, XW Tsang, T Strugnell, NC Zhang, XY Jin, YF Muller, JP Lewis, P Barnsley, M Hobson, P Disney, M Roberts, G Dunderdale, M Doll, C d'Entremont, RP Hu, BX Liang, SL Privette, JL Roy, D AF Schaaf, CB Gao, F Strahler, AH Lucht, W Li, XW Tsang, T Strugnell, NC Zhang, XY Jin, YF Muller, JP Lewis, P Barnsley, M Hobson, P Disney, M Roberts, G Dunderdale, M Doll, C d'Entremont, RP Hu, BX Liang, SL Privette, JL Roy, D TI First operational BRDF, albedo nadir reflectance products from MODIS SO REMOTE SENSING OF ENVIRONMENT LA English DT Article ID BROAD-BAND ALBEDO; BIDIRECTIONAL REFLECTANCE; EOS-MODIS; LAND-COVER; SURFACE ALBEDO; AVHRR DATA; SATELLITE-OBSERVATIONS; SPECTRAL ALBEDO; RETRIEVAL; ALGORITHM AB With the launch of NASA's Terra satellite and the MODerate Resolution Imaging Spectroradiometer (MODIS), operational Bidirectional Reflectance Distribution Function (BRDF) and albedo products are now being made available to the scientific community. The MODIS BRDF/Albedo algorithm makes use of a semiempirical kernel-driven bidirectional reflectance model and multidate, multispectral data to provide global 1-km gridded and tiled products of the land surface every 16 days. These products include directional hemispherical albedo (black-sky albedo), bihemispherical albedo (white-sky albedo), Nadir BRDF-Adjusted surface Reflectances (MBAR), model parameters describing the BRDF, and extensive quality assurance information. The algorithm has been consistently producing albedo and NBAR for the public since July 2000. Initial evaluations indicate a stable BRDF/Albedo Product, where, for example, the spatial and temporal progression of phenological characteristics is easily detected in the NBAR and albedo results. These early beta and provisional products auger well for the routine production of stable MODIS-derived BRDF parameters, nadir reflectances, and albedos for use by the global observation and modeling communities. (C) 2002 Elsevier Science Inc. All rights reserved. C1 Boston Univ, Dept Geog, Boston, MA 02215 USA. Boston Univ, Ctr Remote Sensing, Boston, MA 02215 USA. Beijing Normal Univ, Ctr Remote Sensing, Beijing 100875, Peoples R China. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Maryland, Dept Geog, College Pk, MD 20742 USA. York Univ, Dept Phys & Astron, N York, ON M3J 1P3, Canada. Atmospher & Environm Res Inc, Lexington, MA 02421 USA. Univ Coll Swansea, Dept Geog, Swansea SA2 8PP, W Glam, Wales. UCL, Dept Geog, London WC1E 6BT, England. UCL, Dept Geomat Engn, London WC1E 6BT, England. Potsdam Klimafolgenforsch, PIK, D-14412 Potsdam, Germany. RP Schaaf, CB (reprint author), Boston Univ, Dept Geog, 675 Commonwealth Ave, Boston, MA 02215 USA. EM schaaf@bu.edu RI Zhang, Xiaoyang/E-3208-2010; Lewis, Philip/C-1588-2008; Lucht, Wolfgang/G-2180-2011; Privette, Jeffrey/G-7807-2011; Disney, Mathias/C-1889-2008; liang, shunlin/C-2809-2015 OI Lewis, Philip/0000-0002-8562-0633; Lucht, Wolfgang/0000-0002-3398-8575; Privette, Jeffrey/0000-0001-8267-9894; NR 38 TC 1054 Z9 1113 U1 14 U2 174 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD NOV PY 2002 VL 83 IS 1-2 BP 135 EP 148 AR PII S0034-4257(02)00091-3 DI 10.1016/S0034-4257(02)00091-3 PG 14 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA 613YW UT WOS:000179160200010 ER PT J AU Liang, SL Fang, HL Chen, MZ Shuey, CJ Walthall, C Daughtry, C Morisette, J Schaaf, C Strahler, A AF Liang, SL Fang, HL Chen, MZ Shuey, CJ Walthall, C Daughtry, C Morisette, J Schaaf, C Strahler, A TI Validating MODIS land surface reflectance and albedo products: methods and preliminary results SO REMOTE SENSING OF ENVIRONMENT LA English DT Article ID OPERATIONAL ATMOSPHERIC CORRECTION; LANDSAT-5 THEMATIC MAPPER; NARROW-BAND; CORRECTION ALGORITHM; AEROSOL; GLACIER; IMAGERY AB This paper presents the general methods and some preliminary results of validating Moderate-Resolution Imaging Spectroradiometer (MODIS) land surface reflectance and albedo products using ground measurements and Enhanced Thematic Mapper Plus (ETM+) imagery. Since ground "point" measurements are not suitable for direct comparisons with MODIS pixels of about 1 km over heterogeneous landscapes, upscaling based on high-resolution remotely sensed imagery is critical. In this study, ground measurements at Beltsville, MD were used to calibrate land surface reflectance and albedo products derived from ETM+ imagery at 30 m, which were then aggregated to the MODIS resolution for determining the accuracy of the following land surface products: (1) bidirectional reflectance from atmospheric correction, (2) bidirectional reflectance distribution function (BRDF), (3) broadband albedos, and (4) nadir BRDF-adjusted reflectance. The initial validation results from ground measurements and two ETM+ images acquired on October 2 and November 3, 2000 showed that these products are reasonably accurate, with typically less than 5% absolute error. Final conclusions on their accuracy depend on more validation results. (C) 2002 Elsevier Science Inc. All rights reserved. C1 Univ Maryland, Dept Geog, Lab Global Remote Sensing Studies, College Pk, MD 20742 USA. ARS, Hydrol & Remote Sensing Lab, USDA, Beltsville, MD USA. NASA, Goddard Space Flight Ctr, Biospher Sci Branch, Greenbelt, MD 20771 USA. Boston Univ, Dept Geog, Boston, MA 02215 USA. Boston Univ, Ctr Remote Sensing, Boston, MA 02215 USA. RP Liang, SL (reprint author), Univ Maryland, Dept Geog, Lab Global Remote Sensing Studies, 2181 LeFrak Hall, College Pk, MD 20742 USA. RI liang, shunlin/C-2809-2015 NR 28 TC 192 Z9 226 U1 8 U2 38 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD NOV PY 2002 VL 83 IS 1-2 BP 149 EP 162 AR PII S0034-4257(02)00092-5 DI 10.1016/S0034-4257(02)00092-5 PG 14 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA 613YW UT WOS:000179160200011 ER PT J AU Hall, DK Riggs, GA Salomonson, VV DiGirolamo, NE Bayr, KJ AF Hall, DK Riggs, GA Salomonson, VV DiGirolamo, NE Bayr, KJ TI MODIS snow-cover products SO REMOTE SENSING OF ENVIRONMENT LA English DT Article ID IMAGING SPECTRORADIOMETER MODIS; SATELLITE DATA; RESOLUTION; ALGORITHM; EOS-AM1 AB On December 18, 1999, the Terra satellite was launched with a complement of five instruments including the Moderate Resolution Imaging Spectroradiometer (MODIS). Many geophysical products are derived from MODIS data including global snow-cover products. MODIS snow and ice products have been available through the National Snow and Ice Data Center (NSIDC) Distributed Active Archive Center (DAAC) since September 13, 2000. MODIS snow-cover products represent potential improvement to or enhancement of the currently available operational products mainly because the MODIS products are global and 500-m resolution, and have the capability to separate most snow and clouds. The MODIS snow-mapping algorithms are automated, which means that a consistent data set may be generated for long-term climate studies that require snow-cover information. Extensive quality assurance (QA) information is stored with the products.. The MODIS snow product suite begins with a 500-m resolution, 2330-km swath snow-cover map, which is then gridded to an integerized sinusoidal grid to produce daily and 8-day composite tile products. The sequence proceeds to a climate-modeling grid (CMG) product at 0.05degrees resolution, with both daily and 8-day composite products. Each pixel of the daily CMG contains fraction of snow cover from 40% to 100%. Measured errors of commission in the CMG are low, for example, on the continent of Australia in the spring, they vary from 0.02% to 0.10%. Near-term enhancements include daily snow albedo and fractional snow cover. A case study from March 6, 2000, involving MODIS data and field and aircraft measurements, is presented to show some early validation work. (C) 2002 Elsevier Science Inc. All rights reserved. C1 NASA, Goddard Space Flight Ctr, Hydrol Sci Branch, Greenbelt, MD 20771 USA. Keene State Coll, Dept Geog, Keene, NH 03431 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Sci Syst & Applicat Inc, Lanham, MD 20706 USA. RP Hall, DK (reprint author), NASA, Goddard Space Flight Ctr, Hydrol Sci Branch, Code 974, Greenbelt, MD 20771 USA. RI Hall, Dorothy/D-5562-2012 NR 28 TC 533 Z9 590 U1 9 U2 67 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD NOV PY 2002 VL 83 IS 1-2 BP 181 EP 194 AR PII S0034-4257(02)00095-0 DI 10.1016/S0034-4257(02)00095-0 PG 14 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA 613YW UT WOS:000179160200013 ER PT J AU Myneni, RB Hoffman, S Knyazikhin, Y Privette, JL Glassy, J Tian, Y Wang, Y Song, X Zhang, Y Smith, GR Lotsch, A Friedl, M Morisette, JT Votava, P Nemani, RR Running, SW AF Myneni, RB Hoffman, S Knyazikhin, Y Privette, JL Glassy, J Tian, Y Wang, Y Song, X Zhang, Y Smith, GR Lotsch, A Friedl, M Morisette, JT Votava, P Nemani, RR Running, SW TI Global products of vegetation leaf area and fraction absorbed PAR from year one of MODIS data SO REMOTE SENSING OF ENVIRONMENT LA English DT Article ID FPAR ALGORITHM; LAND; INDEX; ATMOSPHERE; RADIATION; COVER; NDVI; LAI AB An algorithm based on the physics of radiative transfer in vegetation canopies for the retrieval of vegetation green leaf area index (LAI) and fraction of absorbed photosynthetically active radiation (FPAR) from surface reflectances was developed and implemented for operational processing prior to the launch of the moderate resolution imaging spectroradiometer (MODIS) aboard the TERRA platform in December of 1999. The performance of the algorithm has been extensively tested in prototyping activities prior to operational production. Considerable attention was paid to characterizing the quality of the product and this information is available to the users as quality assessment (QA) accompanying the product. The MODIS LAI/FPAR product has been operationally produced from day one of science data processing from MODIS and is available free of charge to the users from the Earth Resources Observation System (EROS) Data Center Distributed Active Archive Center. Current and planned validation activities are aimed at evaluating the product at several field sites representative of the six structural biomes. Example results illustrating the physics and performance of the algorithm are presented together with initial QA and validation results. Potential users of the product are advised of the provisional nature of the product in view of changes to calibration, geolocation, cloud screening, atmospheric correction and ongoing validation activities. (C) 2002 Published by Elsevier Science Inc. C1 Boston Univ, Dept Geog, Boston, MA 02215 USA. Univ Montana, Sch Forestry, Missoula, MT 59812 USA. NASA, Goddard Space Flight Ctr, Biospher Sci Branch, Greenbelt, MD 20771 USA. RP Myneni, RB (reprint author), Boston Univ, Dept Geog, 675 Commonwealth Ave, Boston, MA 02215 USA. RI Privette, Jeffrey/G-7807-2011; Myneni, Ranga/F-5129-2012 OI Privette, Jeffrey/0000-0001-8267-9894; NR 29 TC 859 Z9 923 U1 32 U2 184 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD NOV PY 2002 VL 83 IS 1-2 BP 214 EP 231 AR PII S0034-4257(02)00074-3 DI 10.1016/S0034-4257(02)00074-3 PG 18 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA 613YW UT WOS:000179160200015 ER PT J AU Privette, JL Myneni, RB Knyazikhin, Y Mukelabai, M Roberts, G Tian, Y Wang, Y Leblanc, SG AF Privette, JL Myneni, RB Knyazikhin, Y Mukelabai, M Roberts, G Tian, Y Wang, Y Leblanc, SG TI Early spatial and temporal validation of MODIS LAI product in the Southern Africa Kalahari SO REMOTE SENSING OF ENVIRONMENT LA English DT Article ID LEAF-AREA INDEX; PHOTOSYNTHETICALLY ACTIVE RADIATION; MISR DATA; FRACTION; STANDS AB We evaluate the operational MODIS Leaf Area Index (LAI) product using field-sampled data collected at five sites in southern Africa in March 2000. One site (Mongu, Zambia) was sampled monthly throughout the year. All sites were along the International Geosphere Biosphere Programme's (IGBP) Kalahari Transect, which features progressively lower annual precipitation, and hence, lower vegetation productivity, from north to south. The soils are consistently sandy. At each site, we sampled the vegetation overstory along three 750-m transects using the Tracing Radiation and Architecture in Canopies (TRAC) instrument. The resulting plant area index values were adjusted with ancillary stem area data to estimate LAI. Despite some instrument characterization and production issues in the first year of MODIS operations, our results suggest the first-year MODIS LAI algorithm correctly accommodates structural and phenological variability in semiarid woodlands and savannas, and is accurate to within the uncertainty of the validation approach used here. Limitations of this study and its conclusions are also discussed. (C) 2002 Published by Elsevier Science Inc. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Canada Ctr Remote Sensing, Ottawa, ON K1A OY7, Canada. UCL, Dept Geog, London, England. Meteorol Off, Mongu, Zambia. Boston Univ, Dept Geog, Boston, MA 02215 USA. RP Privette, JL (reprint author), NASA, Goddard Space Flight Ctr, Code 923, Greenbelt, MD 20771 USA. EM jeff.privette@gsfc.nasa.gov RI Privette, Jeffrey/G-7807-2011; Myneni, Ranga/F-5129-2012 OI Privette, Jeffrey/0000-0001-8267-9894; NR 29 TC 99 Z9 116 U1 6 U2 16 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD NOV PY 2002 VL 83 IS 1-2 BP 232 EP 243 AR PII S0034-4257(02)00075-5 DI 10.1016/S0034-4257(02)00075-5 PG 12 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA 613YW UT WOS:000179160200016 ER PT J AU Justice, CO Giglio, L Korontzi, S Owens, J Morisette, JT Roy, D Descloitres, J Alleaume, S Petitcolin, F Kaufman, Y AF Justice, CO Giglio, L Korontzi, S Owens, J Morisette, JT Roy, D Descloitres, J Alleaume, S Petitcolin, F Kaufman, Y TI The MODIS fire products SO REMOTE SENSING OF ENVIRONMENT LA English DT Article ID INFRARED DATA; EOS-MODIS; EMISSIONS; BIOMASS; RADIOMETER; AFRICA; ASTER AB Fire products are now available from the Moderate Resolution Imaging Spectroradiometer (MODIS) including the only current global daily active fire product. This paper describes the algorithm, the products and the associated validation activities. High-resolution ASTER data, which are acquired simultaneously with MODIS, provide a unique opportunity for MODIS validation. Results are presented from a preliminary active fire validation study in Africa. The prototype MODIS burned area product is described, and an example is given for southern Africa of how this product can be used in modeling pyrogenic emissions. The MODIS Fire Rapid Response System and a web-based mapping system for enhanced distribution are described and the next steps for the MODIS fire products are outlined. (C) 2002 Elsevier Science Inc. All rights reserved. C1 Univ Maryland, Dept Geog, College Pk, MD 20742 USA. ACRI ST, Sophia Antipolis, France. Univ Virginia, Dept Environm Sci, Charlottesville, VA 22903 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Sci Syst & Applicat Inc, Lanham, MD USA. RP Justice, CO (reprint author), Univ Maryland, Dept Geog, 2181 LeFrak Hall, College Pk, MD 20742 USA. EM justice@hermes.geog.umd.edu NR 39 TC 519 Z9 554 U1 4 U2 54 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD NOV PY 2002 VL 83 IS 1-2 BP 244 EP 262 AR PII S0034-4257(02)00076-7 DI 10.1016/S0034-4257(02)00076-7 PG 19 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA 613YW UT WOS:000179160200017 ER PT J AU Roy, DP Lewis, PE Justice, CO AF Roy, DP Lewis, PE Justice, CO TI Burned area mapping using multi-temporal moderate spatial resolution data - a bi-directional reflectance model-based expectation approach SO REMOTE SENSING OF ENVIRONMENT LA English DT Article ID EOS-MODIS; VEGETATION INDEXES; INFRARED DATA; FOREST-FIRES; LAND; AFRICA; ALGORITHM; BIOMASS; ALBEDO; INFORMATION AB While remote sensing offers the capability for monitoring land surface changes, extracting the change information from satellite data requires effective and automated change detection techniques. The majority of change detection techniques rely on empirically derived thresholds to differentiate changes from background variations, which are often considered noise. Over large areas, reliable threshold definition is problematic due to variations in both the surface state and those imposed by the sensing system. A new approach to change detection, applicable to high-temporal frequency satellite data, that maps the location and approximate day of change occurrence is described. The algorithm may be applied to a range of change detection applications by using appropriate wavelengths. The approach is applied here to the problem of mapping burned areas using moderate spatial resolution satellite data. A bi-directional reflectance model is inverted against multi-temporal land surface reflectance observations, providing an expectation and uncertainty of subsequent observations through time. The algorithm deals with angular variations observed in multi-temporal satellite data and enables the use of a statistical measure to detect change from a previously observed state. The algorithm is applied independently to geolocated pixels over a long time series of reflectance observations. Large discrepancies between predicted and measured values are attributed to change. A temporal consistency threshold is used to differentiate between temporary changes considered as noise and persistent changes of interest. The algorithm is adaptive to the number, viewing and illumination geometry of the observations, and to the amount of noise in the data. The approach is demonstrated using 56 days of Moderate Resolution Imaging Spectroradiometer (MODIS) land surface reflectance data generated for Southern Africa during the 2000 burning season. Qualitatively, the results show high correspondence with contemporaneous MODIS active fire detection results and reveal a coherent spatio-temporal progression of burning. Validation of these results is in progress and recommendations for future research, pending the availability of independent validation data sets, are made. This approach is now being considered for the MODIS burned area algorithm. (C) 2002 Elsevier Science Inc. All rights reserved. C1 Univ Maryland, Dept Geog, College Pk, MD 20742 USA. UCL, Dept Geog, Remote Sensing Unit, London WC1H 0AP, England. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Roy, DP (reprint author), Univ Maryland, Dept Geog, 1113 LeFrak Hall, College Pk, MD 20742 USA. EM droy@kratmos.gsfc.nasa.gov RI Lewis, Philip/C-1588-2008 OI Lewis, Philip/0000-0002-8562-0633 NR 61 TC 175 Z9 188 U1 3 U2 24 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0034-4257 J9 REMOTE SENS ENVIRON JI Remote Sens. Environ. PD NOV PY 2002 VL 83 IS 1-2 BP 263 EP 286 AR PII S0034-4257(02)00077-9 DI 10.1016/S0034-4257(02)00077-9 PG 24 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA 613YW UT WOS:000179160200018 ER PT J AU Acuna, MH AF Acuna, MH TI Space-based magnetometers SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Review ID MAGNETIC-FIELD EXPERIMENT; PROSPECTOR-DISCOVERY-MISSION; DANISH OERSTED SATELLITE; FLUXGATE MAGNETOMETER; LUNAR-PROSPECTOR; DIGITAL DETECTION; POWER-SYSTEMS; WEATHER; MARS; SCIENCE AB The general characteristics and system level concepts for space-based magnetometers are presented to illustrate the instruments, principles, and tools involved in making accurate magnetic field measurements in space. Special consideration is given to the most important practical problems that need to be solved to ensure the accuracy of the measurements and their overall impact on system design and mission costs. Several types of instruments used to measure magnetic fields aboard spacecraft and their capabilities and limitations are described according to whether they measure scalar or vector fields. The very large dynamic range associated with magnetic fields of natural origin generally dictates the use of optimized designs for each particular space mission although some wide-range, multimission magnetometers have been developed and used. Earth-field magnetic mapping missions are the most demanding in terms of absolute accuracy and resolution, approaching <1 part in 100 000 in magnitude and a few arcsec in direction. The difficulties of performing sensitive measurements aboard spacecraft, which may not be magnetically clean, represent a fundamental problem which must be addressed immediately at the planning stages of any space mission that includes these measurements. The use of long, deployable booms to separate the sensors from the sources of magnetic contamination, and their impact on system design are discussed. The dual magnetometer technique, which allows the separation of fields of external and spacecraft origin, represents an important space magnetometry tool which can result in significant savings in complex contemporary spacecraft built with minimum magnetic constraints. Techniques for in-flight estimation of magnetometer biases and sensor alignment are discussed briefly, and highlight some basic considerations within the scope and complexity of magnetic field data processing and reduction. The emerging field of space weather is also discussed, including the essential role that space-based magnetic field measurements play in this complex science, which is just in its infancy. Finally, some considerations for the future of space-based magnetometers are presented. Miniature, mass produced sensors based on magnetoresistance effects and micromachined structures have made significant advances in sensitivity but have yet to reach the performance level required for accurate space measurements. The miniaturization of spacecraft and instruments to reduce launch costs usually results in significantly increased magnetic contamination problems and degraded instrument performance parameters, a challenge that has yet to be solved satisfactorily for "world-class" science missions. The rapidly disappearing manufacturing capabilities for high-grade, low noise, soft magnetic materials of the Permalloy family is a cause of concern for the development of high performance fluxgate magnetometers for future space missions. C1 NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. RP NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Code 695, Greenbelt, MD 20771 USA. EM mario.acuna.1@gsfc.nasa.gov NR 110 TC 74 Z9 78 U1 4 U2 30 PU AMER INST PHYSICS PI MELVILLE PA 1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA SN 0034-6748 EI 1089-7623 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD NOV PY 2002 VL 73 IS 11 BP 3717 EP 3736 DI 10.1063/1.1510570 PG 20 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 607YK UT WOS:000178818200001 ER PT J AU Moran, TG AF Moran, TG TI Solar and heliospheric Observatory/Solar ultraviolet measurements of estimated radiation ultraviolet array detector distortion correction SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article ID TRANSITION REGION; SUMER; SOHO AB We present the technique used to correct the geometric distortion in the Solar and Heliospheric Observatory/Solar Ultraviolet Measurement of Estimated Radiation (SOHO/SUMER) ultraviolet spectrograph images. Electric and magnetic fields within the SUMER crossed delay line detectors and optical misalignment within the SUMER spectrograph cause focal plane image distortion, which leads to errors in wavelength and position measurements if not corrected. A high degree of precision is required in geometric correction in order to achieve the required accuracy in solar ultraviolet line position measurements. We characterize the distortion using a combination of laboratory and in situ measurements to compute tables of horizontal and vertical pixel shift vectors and correct the distorted frame by interpolation to within 0.11 pixel rms error in wavelength pixel and 0.25 pixel rms error in spatial pixel. The correction allows measurements of line-of-sight solar ion velocities with 1 km/s accuracy. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Catholic Univ Amer, Washington, DC 20560 USA. RP Moran, TG (reprint author), NASA, Goddard Space Flight Ctr, Code 682-3, Greenbelt, MD 20771 USA. NR 13 TC 6 Z9 6 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD NOV PY 2002 VL 73 IS 11 BP 3982 EP 3987 DI 10.1063/1.1512326 PG 6 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 607YK UT WOS:000178818200042 ER PT J AU Limketkai, B Granger, J Weilert, M Hahn, I AF Limketkai, B Granger, J Weilert, M Hahn, I TI Multiple channel superconducting quantum interference device controller using a digital signal processor SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article ID HIGH-RESOLUTION THERMOMETER AB We report on the design, performance, and limitations of an improved multiple superconducting quantum interference device (SQUID) controller based upon a digital signal processor. The flux noise level of the dc SQUID controller system is comparable with the commercial analog system, similar to4 muPhi(0)/Hz(1/2) at 100 Hz. The measured maximum slew rate of the system is approximately 800 Phi(0)/s. The current system could control up to five SQUID channels. (C) 2002 American Institute of Physics. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Hahn, I (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM Inseob.Hahn@jpl.nasa.gov NR 6 TC 2 Z9 2 U1 0 U2 0 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0034-6748 J9 REV SCI INSTRUM JI Rev. Sci. Instrum. PD NOV PY 2002 VL 73 IS 11 BP 4010 EP 4013 DI 10.1063/1.1511805 PG 4 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 607YK UT WOS:000178818200046 ER PT J AU Stern, DP AF Stern, DP TI A millennium of geomagnetism SO REVIEWS OF GEOPHYSICS LA English DT Review DE geomagnetism; history; lodestone; magnetic survey; geomagnetic dynamo; solar magnetism ID MAGNETIC-FIELD; MAGNETOSPHERIC PHYSICS; BRIEF-HISTORY; GEODYNAMO; CORE; SIMULATIONS; REVERSALS; SCIENCE; MANTLE; EARTH AB [1] The history of geomagnetism began around the year 1000 with the discovery in China of the magnetic compass. Methodical studies of the Earth's field started in 1600 with William Gilbert's De Magnete [Gilbert, 1600] and continued with the work of (among others) Edmond Halley, Charles Augustin de Coulomb, Carl Friedrich Gauss, and Edward Sabine. The discovery of electromagnetism by Hans Christian Oersted and Andre-Marie Ampere led Michael Faraday to the notion of fluid dynamos, and the observation of sunspot magnetism by George Ellery Hale led Sir Joseph Larmor in 1919 to the idea that such dynamos could sustain themselves naturally in convecting conducting fluids. From that came modern dynamo theory, of both the solar and terrestrial magnetic fields. Paleomagnetic studies revealed that the Earth's dipole had undergone reversals in the distant past, and these became the critical evidence in establishing plate tectonics. Finally, the recent availability of scientific spacecraft has demonstrated the intricacy of the Earth's distant magnetic field, as well as the existence of magnetic fields associated with other planets and with satellites in our solar system. C1 NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. RP Stern, DP (reprint author), NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Code 695, Greenbelt, MD 20771 USA. NR 160 TC 33 Z9 33 U1 5 U2 18 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 8755-1209 J9 REV GEOPHYS JI Rev. Geophys. PD NOV PY 2002 VL 40 IS 3 AR 1007 DI 10.1029/2000RG000097 PG 30 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 639YG UT WOS:000180657400001 ER PT J AU Harris, CE Shuart, MJ Gray, HR AF Harris, CE Shuart, MJ Gray, HR TI Emerging materials for revolutionary aerospace vehicle structures and propulsion systems SO SAMPE JOURNAL LA English DT Article ID CARBON NANOTUBES; COMPOSITES; STRENGTH AB The NASA Strategic Plan identifies the long-term goal of providing safe and affordable space access, orbital transfer and interplanetary transportation capabilities to enable scientific research, human and robotic exploration, and the commercial development of space. Numerous scientific and engineering breakthroughs will be required to develop the technology required to achieve this goal. Critical technologies include advanced vehicle primary and secondary structure, radiation protection, propulsion and power systems, fuel storage, electronics and devices, sensors and science instruments, and medical diagnostics and treatment. Advanced materials with revolutionary new capabilities are an essential element of each of these technologies. A survey of emerging materials with applications to aerospace vehicle structures and propulsion systems was conducted to assist in long-term agency mission planning. The comprehensive survey identified materials already under development that could be available in five to ten years and those that are still in the early research phase and may not be available for another 20 to 30 years. The survey also includes the results of several systems analysis studies that highlight the enormous potential of one revolutionary new material, carbon nanotubes. C1 NASA, Langley Res Ctr, Hampton, VA 23665 USA. NASA, Glenn Res Ctr, Div Mat, Cleveland, OH USA. RP Harris, CE (reprint author), NASA, Langley Res Ctr, Hampton, VA 23665 USA. NR 42 TC 2 Z9 2 U1 0 U2 2 PU SAMPE PUBLISHERS PI COVINA PA 1161 PARKVIEW DRIVE, COVINA, CA 91722 USA SN 0091-1062 J9 SAMPE J JI Sampe J. PD NOV-DEC PY 2002 VL 38 IS 6 BP 33 EP 43 PG 11 WC Engineering, Multidisciplinary; Materials Science, Multidisciplinary SC Engineering; Materials Science GA 609AP UT WOS:000178880700009 ER PT J AU Hoffert, MI Caldeira, K Benford, G Criswell, DR Green, C Herzog, H Jain, AK Kheshgi, HS Lackner, KS Lewis, JS Lightfoot, HD Manheimer, W Mankins, JC Mauel, ME Perkins, LJ Schlesinger, ME Volk, T Wigley, TML AF Hoffert, MI Caldeira, K Benford, G Criswell, DR Green, C Herzog, H Jain, AK Kheshgi, HS Lackner, KS Lewis, JS Lightfoot, HD Manheimer, W Mankins, JC Mauel, ME Perkins, LJ Schlesinger, ME Volk, T Wigley, TML TI Advanced technology paths to global climate stability: Energy for a greenhouse planet SO SCIENCE LA English DT Review ID SPACE SOLAR POWER; CARBON-DIOXIDE; DISPOSAL; FUTURE; FUSION; STABILIZATION; EMISSIONS; SYSTEMS; FUELS AB Stabilizing the carbon dioxide induced component of climate change is an energy problem. Establishment of a course toward such stabilization will require the development within the coming decades of primary energy sources that do not emit carbon dioxide to the atmosphere, in addition to efforts to reduce end-use energy demand. Mid-century primary power requirements that are free of carbon dioxide emissions could be several times what we now derive from fossil fuels (similar to10(13) watts), even with improvements in energy efficiency. Here we survey possible future energy sources, evaluated for their capability to supply massive amounts of carbon emission free energy and for their potential for large-scale commercialization. Possible candidates for primary energy sources include terrestrial solar and wind energy, solar power satellites, biomass, nuclear fission, nuclear fusion, fission-fusion hybrids, and fossil fuels from which carbon has been sequestered. Non primary power technologies that could contribute to climate stabilization include efficiency improvements, hydrogen production, storage and transport, superconducting global electric grids, and geoengineering. All of these approaches currently have severe deficiencies that limit their ability to stabilize global climate. We conclude that a broad range of intensive research and development is urgently needed to produce technological options that can allow both climate stabilization and economic development. C1 NYU, Dept Phys, New York, NY 10003 USA. NYU, Dept Biol, New York, NY 10003 USA. Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Univ Calif Irvine, Dept Phys & Astron, Irvine, CA 92697 USA. Univ Houston, Inst Space Syst Operat, Houston, TX 77204 USA. McGill Univ, Dept Econ, Montreal, PQ H3A 2T7, Canada. MIT, Lab Energy & Environm, Cambridge, MA 02139 USA. Univ Illinois, Dept Atmospher Sci, Urbana, IL 61801 USA. Exxon Mobil Res & Engn Co, Annandale, NJ 08801 USA. Columbia Univ, Dept Earth & Environm Engn, New York, NY 10027 USA. Columbia Univ, Dept Appl Phys & Appl Math, New York, NY 10027 USA. Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. McGill Univ, Ctr Climate & Global Change Res, Montreal, PQ H3A 2K6, Canada. USN, Res Lab, Div Plasma Phys, Washington, DC 20375 USA. Natl Ctr Atmospher Res, Boulder, CO 80307 USA. NASA Headquarters, Washington, DC 20546 USA. RP Hoffert, MI (reprint author), NYU, Dept Phys, 4 Washington Pl, New York, NY 10003 USA. RI Wigley, Tom/B-4705-2008; Caldeira, Ken/E-7914-2011; Jain, Atul/D-2851-2016 OI Jain, Atul/0000-0002-4051-3228 NR 80 TC 592 Z9 607 U1 48 U2 349 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 NOV 1 PY 2002 VL 298 IS 5595 BP 981 EP 987 DI 10.1126/science.1072357 PG 7 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 609XQ UT WOS:000178932000044 PM 12411695 ER PT J AU Lin, RP Dennis, BR Hurford, GJ Smith, DM Zehnder, A Harvey, PR Curtis, DW Pankow, D Turin, P Bester, M Csillaghy, A Lewis, M Madden, N Van Beek, HF Appleby, M Raudorf, T McTiernan, J Ramaty, R Schmahl, E Schwartz, R Krucker, S Abiad, R Quinn, T Berg, P Hashii, M Sterling, R Jackson, R Pratt, R Campbell, RD Malone, D Landis, D Barrington-Leigh, CP Slassi-Sennou, S Cork, C Clark, D Amato, D Orwig, L Boyle, R Banks, IS Shirey, K Tolbert, AK Zarro, D Snow, F Thomsen, K Henneck, R Mchedlishvili, A Ming, P Fivian, M Jordan, J Wanner, R Crubb, J Preble, J Matranga, M Benz, A Hudson, H Canfield, RC Holman, GD Crannell, C Kosugi, T Emslie, AG Vilmer, N Brown, JC Johns-Krull, C Aschwanden, M Metcalf, T Conway, A AF Lin, RP Dennis, BR Hurford, GJ Smith, DM Zehnder, A Harvey, PR Curtis, DW Pankow, D Turin, P Bester, M Csillaghy, A Lewis, M Madden, N Van Beek, HF Appleby, M Raudorf, T McTiernan, J Ramaty, R Schmahl, E Schwartz, R Krucker, S Abiad, R Quinn, T Berg, P Hashii, M Sterling, R Jackson, R Pratt, R Campbell, RD Malone, D Landis, D Barrington-Leigh, CP Slassi-Sennou, S Cork, C Clark, D Amato, D Orwig, L Boyle, R Banks, IS Shirey, K Tolbert, AK Zarro, D Snow, F Thomsen, K Henneck, R Mchedlishvili, A Ming, P Fivian, M Jordan, J Wanner, R Crubb, J Preble, J Matranga, M Benz, A Hudson, H Canfield, RC Holman, GD Crannell, C Kosugi, T Emslie, AG Vilmer, N Brown, JC Johns-Krull, C Aschwanden, M Metcalf, T Conway, A TI The Reuven Ramaty high-energy solar spectroscopic imager (RHESSI) SO SOLAR PHYSICS LA English DT Article ID WIND SPACECRAFT; ABUNDANCES; PARTICLES; PLASMA; FLARES AB RHESSI is the sixth in the NASA line of Small Explorer (SMEX) missions and the first managed in the Principal Investigator mode, where the PI is responsible for all aspects of the mission except the launch vehicle. RHESSI is designed to investigate particle acceleration and energy release in solar flares, through imaging and spectroscopy of hard X-ray/gamma-ray continua emitted by energetic electrons, and of gamma-ray lines produced by energetic ions. The single instrument consists of an imager, made up of nine bi-grid rotating modulation collimators (RMCs), in front of a spectrometer with nine cryogenically-cooled germanium detectors (GeDs), one behind each RMC. It provides the first high-resolution hard X-ray imaging spectroscopy, the first high-resolution gamma-ray line spectroscopy, and the first imaging above 100 keV including the first imaging of gamma-ray lines. The spatial resolution is as fine as similar to 2.3 are see with a full-Sun (greater than or similar to1degrees) field of view, and the spectral resolution is similar to 1 - 10 keV FWHM over the energy range from soft X-rays (3 keV) to gamma-rays (17 MeV). An automated shutter system allows a wide dynamic range (> 10(7)) of flare intensities to be handled without instrument saturation. Data for every photon is stored in a solid-state memory and telemetered to the ground, thus allowing for versatile data analysis keyed to specific science objectives. The spin-stabilized (similar to 15 rpm) spacecraft is Sun-pointing to within similar to 0.2degrees and operates autonomously. RHESSI was launched on 5 February 2002, into a nearly circular, 38degrees inclination, 600-km altitude orbit and began observations a week later. The mission is operated from Berkeley using a dedicated 11-m antenna for telemetry reception and command uplinks. All data and analysis software are made freely and immediately available to the scientific community. C1 Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Paul Scherrer Inst, CH-5232 Villigen, Switzerland. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. HF van Beek Onsultancy, NL-3971 LB Driebergen, Netherlands. Tecomet, Woburn, MA 01801 USA. Ortec, Oak Ridge, TN 37831 USA. Univ Appl Sci, CH-5210 Windisch, Switzerland. Spectrum Astro, Gilbert, AZ 85233 USA. SpaceWorks Inc, Carefree, AZ 85377 USA. Charles Stark Draper Lab Inc, Cambridge, MA 02139 USA. Univ Maryland, College Pk, MD 20742 USA. Sci Syst & Applicat Inc, Greenbelt, MD 20771 USA. Swiss Fed Inst Technol, CH-8092 Zurich, Switzerland. Montana State Univ, Bozeman, MT 59717 USA. ISAS, Sagamihara, Kanagawa, Japan. Univ Alabama, Huntsville, AL 35899 USA. Observ Paris, Meudon, France. Univ Glasgow, Glasgow G12 8QW, Lanark, Scotland. Rice Univ, Houston, TX 77005 USA. Lockheed Martin, Palo Alto, CA 94304 USA. Open Univ, Milton Keynes MK7 6AA, Bucks, England. L3 Commun, New York, NY 10016 USA. RP Lin, RP (reprint author), Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. RI Holman, Gordon/C-9548-2012; Dennis, Brian/C-9511-2012; OI Barrington-Leigh, Christopher/0000-0002-3929-5390 NR 16 TC 999 Z9 1010 U1 2 U2 24 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-0938 J9 SOL PHYS JI Sol. Phys. PD NOV PY 2002 VL 210 IS 1-2 BP 3 EP 32 DI 10.1023/A:1022428818870 PG 30 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 644YE UT WOS:000180948200001 ER PT J AU Smith, DM Lin, RP Turin, P Curtis, DW Primbsch, JH Campbell, RD Abiad, R Schroeder, P Cork, CP Hull, EL Landis, DA Madden, NW Malone, D Pehl, RH Raudorf, T Sangsingkeow, P Boyle, R Banks, IS Shirey, K Schwartz, R AF Smith, DM Lin, RP Turin, P Curtis, DW Primbsch, JH Campbell, RD Abiad, R Schroeder, P Cork, CP Hull, EL Landis, DA Madden, NW Malone, D Pehl, RH Raudorf, T Sangsingkeow, P Boyle, R Banks, IS Shirey, K Schwartz, R TI The RHESSI spectrometer SO SOLAR PHYSICS LA English DT Article ID DETECTORS; SPECTRA AB RHESSI observes solar photons over three orders of magnitude in energy (3 keV to 17 MeV) with a single instrument: a set of nine cryogenically cooled coaxial germanium detectors. With their extremely high energy resolution, RHESSI can resolve the line shape of every known solar gamma-ray line except the neutron capture line at 2.223 MeV. High resolution also allows clean separation of thermal and non-thermal hard X-rays and the accurate measurement of even extremely steep power-law spectra. Detector segmentation, fast signal processing, and two sets of movable attenuators allow RHESSI to make high-quality spectra and images of flares across seven orders of magnitude in intensity. Here we describe the configuration and operation of the RHESSI spectrometer, show early results on in-flight performance, and discuss the principles of spectroscopic data analysis used by the RHESSI software. C1 Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. Univ Calif Berkeley, Lawrence Berkeley Lab, Berkeley, CA 94720 USA. ORTEC, Oak Ridge, TN USA. NASA, Goddard Space Flight Ctr, SSAI, Greenbelt, MD USA. RP Smith, DM (reprint author), Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. NR 14 TC 263 Z9 267 U1 1 U2 4 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-0938 J9 SOL PHYS JI Sol. Phys. PD NOV PY 2002 VL 210 IS 1-2 BP 33 EP 60 DI 10.1023/A:1022400716414 PG 28 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 644YE UT WOS:000180948200002 ER PT J AU Hurford, GJ Schmahl, EJ Schwartz, RA Conway, AJ Aschwanden, MJ Csillaghy, A Dennis, BR Johns-Krull, C Krucker, S Lin, RP McTiernan, J Metcalf, TR Sato, J Smith, DM AF Hurford, GJ Schmahl, EJ Schwartz, RA Conway, AJ Aschwanden, MJ Csillaghy, A Dennis, BR Johns-Krull, C Krucker, S Lin, RP McTiernan, J Metcalf, TR Sato, J Smith, DM TI The RHESSI imaging concept SO SOLAR PHYSICS LA English DT Article ID X-RAY TELESCOPE; GAMMA-RAY; RECONSTRUCTION AB The Reuven Ramaty High-Energy Solar Spectroscopic Imager (RHESSI) observes solar hard X-rays and gamma-rays from 3 keV to 17 MeV with spatial resolution as high as 2.3 are see. Instead of focusing optics, imaging is based on nine rotating modulation collimators that time-modulate the incident flux as the spacecraft rotates. Starting from the arrival time of individual photons, ground-based software then uses the modulated signals to reconstruct images of the source. The purpose of this paper is to convey both an intuitive feel and the mathematical basis for this imaging process. Following a review of the relevant hardware, the imaging principles and the basic back-projection method are described, along with their relation to Fourier transforms. Several specific algorithms (Clean, MEM, Pixons and Forward-Fitting) applicable to RHESSI imaging are briefly described. The characteristic strengths and weaknesses of this type of imaging are summarized. C1 Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. Univ Maryland, Dept Astron, College Pk, MD 20742 USA. NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, SSAI, Greenbelt, MD 20771 USA. Open Univ, Dept Phys & Astron, Milton Keynes MK7 6AA, Bucks, England. Lockheed Martin Adv Technol Ctr, Solar & Astrophys Lab, Dept L9 41, Palo Alto, CA 94304 USA. Univ Appl Sci, CH-5210 Windisch, Switzerland. Rice Univ, Dept Phys & Astron, Houston, TX 77005 USA. Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. Montana State Univ, Dept Phys, Bozeman, MT 59717 USA. RP Hurford, GJ (reprint author), Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. RI Dennis, Brian/C-9511-2012 NR 28 TC 333 Z9 336 U1 2 U2 8 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-0938 J9 SOL PHYS JI Sol. Phys. PD NOV PY 2002 VL 210 IS 1-2 BP 61 EP 86 DI 10.1023/A:1022436213688 PG 26 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 644YE UT WOS:000180948200003 ER PT J AU Schwartz, RA Csillaghy, A Tolbert, AK Hurford, GJ McTiernan, J Zarro, D AF Schwartz, RA Csillaghy, A Tolbert, AK Hurford, GJ McTiernan, J Zarro, D TI RHESSI data analysis software: Rationale and methods SO SOLAR PHYSICS LA English DT Article AB The Reuven Ramaty High-Energy Solar Spectroscopic Imager (RHESSI) performs imaging spectroscopy of the Sun with high spatial and spectral resolution from 3 keV to 17 MeV using indirect Fourier-transform techniques. We review the rationale behind the RHESSI data analysis software, and explain the underlying structure of the software tools. Our goal was to make the large data set available within weeks after the RHESSI launch, and to make it possible for any member of the scientific community to analyze it easily. This paper describes the requirements for the software and explores our decisions to use the SolarSoftWare and Interactive Data Language programming packages, to support both Windows and Unix platforms, and to use object-oriented programming. We also describe how the data are rapidly disseminated and how ancillary data sets are used to enhance the RHESSI science. Finally, we give a schematic overview of some of the data flow through the high-level analysis tools. More information on the data and analysis procedures can be found at the RHESSI Data Center website, http://hesperia.gsfc.nasa.govlrhessidatacenter. C1 NASA, Goddard Space Flight Ctr, SSAI, Greenbelt, MD 20771 USA. Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. Swiss Fed Inst Technol, Inst Astron, CH-8092 Zurich, Switzerland. Univ Appl Sci, CH-5210 Windisch, Switzerland. NASA, Goddard Space Flight Ctr, L3 Corp, Greenbelt, MD 20771 USA. RP Schwartz, RA (reprint author), NASA, Goddard Space Flight Ctr, SSAI, Greenbelt, MD 20771 USA. NR 7 TC 73 Z9 74 U1 1 U2 1 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-0938 J9 SOL PHYS JI Sol. Phys. PD NOV PY 2002 VL 210 IS 1-2 BP 165 EP 191 DI 10.1023/A:1022444531435 PG 27 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 644YE UT WOS:000180948200009 ER PT J AU Aschwanden, MJ Schmahl, E Team, R AF Aschwanden, MJ Schmahl, E Team, R TI Reconstruction of RHESSI solar flare images with a forward fitting method SO SOLAR PHYSICS LA English DT Article ID MAGNETIC RECONNECTION; SPECTROSCOPIC IMAGER; LIKELIHOOD RATIO; HESSI AB We describe a forward-fitting method that has been developed to reconstruct hard Xray images of solar flares from the Ramaty High-Energy Solar Spectroscopic hnager (RHESSI), a Fourier imager with rotation-modulated collimators that was launched on 5 February 2002. The forward-fitting method is based on geometric models that represent a spatial map by a superposition of multiple source structures, which are quantified by circular gaussians (4 parameters per source), elliptical gaussians (6 parameters), or curved ellipticals (7 parameters), designed to characterize real solar flare hard X-ray maps with a minimum number of geometric elements. We describe and demonstrate the use of the forward-fitting algorithm. We perform some 500 simulations of rotation-modulated time profiles of the 9 RHESSI detectors, based on single and multiple source structures, and perform their image reconstruction. We quantify the fidelity of the image reconstruction, as function of photon statistics, and the accuracy of retrieved source positions, widths, and fluxes. We outline applications for which the forward-fitting code is most suitable, such as measurements of the energy-dependent altitude of energy loss near the limb, or footpoint separation during flares. C1 Lockheed Martin ATC, Solar & Astrophys Lab, Dept L9 41, Palo Alto, CA 94304 USA. NASA, Goddard Space Flight Ctr, Solar & Astrophys Lab, Greenbelt, MD 20771 USA. Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. RP Aschwanden, MJ (reprint author), Lockheed Martin ATC, Solar & Astrophys Lab, Dept L9 41, Bldg 252,3251 Hanover St, Palo Alto, CA 94304 USA. EM aschwanden@lmsal.com NR 16 TC 11 Z9 11 U1 0 U2 0 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-0938 J9 SOL PHYS JI Sol. Phys. PD NOV PY 2002 VL 210 IS 1-2 BP 193 EP 211 DI 10.1023/A:1022469811115 PG 19 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 644YE UT WOS:000180948200010 ER PT J AU Sui, LH Holman, GD Dennis, BR Krucker, S Schwartz, RA Tolbert, K AF Sui, LH Holman, GD Dennis, BR Krucker, S Schwartz, RA Tolbert, K TI Modeling images and spectra of a solar flare observed by RHESSI on 20 February 2002 SO SOLAR PHYSICS LA English DT Article ID YOHKOH HARD; RAY; EMISSION; TOP AB We have analyzed a C7.5 limb flare observed by RHESSI on 20 February 2002. The RHESSI images appear to show two footpoints and a loop-top source. Our goal was to determine if the data are consistent with a simple steady-state model in which high-energy electrons are continuously injected at the top of a semicircular flare loop. A comparison of the RHESSI images with simulated images from the model has made it possible for us to identify spurious sources and fluxes in the RHESSI images. We find that the RHESSI results are in many aspects consistent with the model if a thermal source is included between the loop footpoints, but there is a problem with the spectral index of the loop-top source. The thermal source between the footpoints is likely to be a low-lying loop interacting with the northern footpoint of a higher loop containing the loop-top source. C1 NASA, Goddard Space Flight Ctr, CUA, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. NASA, Goddard Space Flight Ctr, SSAI, Greenbelt, MD 20771 USA. RP Sui, LH (reprint author), NASA, Goddard Space Flight Ctr, CUA, Greenbelt, MD 20771 USA. RI Holman, Gordon/C-9548-2012; Dennis, Brian/C-9511-2012 NR 13 TC 28 Z9 28 U1 0 U2 1 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-0938 J9 SOL PHYS JI Sol. Phys. PD NOV PY 2002 VL 210 IS 1-2 BP 245 EP 259 DI 10.1023/A:1022417832283 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 644YE UT WOS:000180948200013 ER PT J AU Gallagher, PT Dennis, BR Krucker, S Schwartz, RA Tolbert, AK AF Gallagher, PT Dennis, BR Krucker, S Schwartz, RA Tolbert, AK TI RHESSI and trace observations of the 21 April 2002 X1.5 flare SO SOLAR PHYSICS LA English DT Article ID KELVIN-HELMHOLTZ INSTABILITIES; RESONANT FLOW INSTABILITIES; CORONAL PLUME MODEL; X-RAY OBSERVATIONS; SOLAR-FLARE; TRANSITION REGION; EXPLORER; PHASE AB Observations of the X1.5 flare on 21 April 2002 are reviewed using the Reuven Ramaty High-Energy Solar Spectroscopic Imager (RHESSI) and the Transition Region and Coronal Explorer (TRACE). The major findings are as follows: (1) The 3 - 25 keV X-rays started < 4 min before the EUV (195 &ANGS;) emission suggesting that the initial energy release heated plasma directly to &GSIM;20 MK, well above the 1.6 MK needed to produce the FeXII (195 &ANGS;) line. (2) Using coaligned 12-25 keV RHESSI and TRACE images, further evidence is found for the existence of hot (15-20 MK) plasma in the 195&ANGS; passband. This hot, diffuse emission is attributed to the presence of the Fe XXIV (192&ANGS;) line within the TRACE 195 &ANGS; passband. (3) The 12-25 keV source centroid moves away from the limb with an apparent velocity of &SIM;9.9 km s(-1), slowing to &SIM; 1.7 km s(-1) after 3 hours, its final altitude being - 140 Mm after - 12 hours. This suggests that the energy release site moves to higher altitudes in agreement with classical flare models. (4) The 50-100 keV emission correlates well with EUV flare ribbons, suggesting thick-target interactions at the footpoints of the magnetic arcade. The 50-100 keV time profile matches the time derivative of the GOES light curve (Neupert effect), which suggests that the same electrons that produced the thick-target hard X-ray emission also heat the plasma seen in soft X-rays. (5) X-ray footpoint emission has an E-3 spectrum down to &SIM;10 keV suggesting a lower electron cutoff energy than previously thought. (6) The hard X-ray (25 - 200 keV) peaks have FWHM durations of &SIM;1 min suggesting a more gradual energy release process than expected. (7) The TRACE images reveal a bright symmetric front propagating away from the main flare site at speeds of &GE; 120 km s(-1). This may be associated with the fast CME observed several minutes later by LASCO. (8) Dark sinuous lanes are observed in the TRACE images that extend almost radially from the post-flare loop system. This 'fan of spines' becomes visible well into the decay phase of the flare and shows evidence for both lateral and downward motions. C1 NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. L3 Com Analyt Corp, Largo, MD 20774 USA. Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. Space Syst & Applicat Inc, Lanham, MD 20706 USA. RP Gallagher, PT (reprint author), NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. RI Dennis, Brian/C-9511-2012; Gallagher, Peter/C-7717-2011 OI Gallagher, Peter/0000-0001-9745-0400 NR 19 TC 98 Z9 98 U1 0 U2 1 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-0938 J9 SOL PHYS JI Sol. Phys. PD NOV PY 2002 VL 210 IS 1-2 BP 341 EP 356 DI 10.1023/A:1022422019779 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 644YE UT WOS:000180948200019 ER PT J AU Share, GH Murphy, RJ Dennis, BR Schwartz, RA Tolbert, AK Lin, RP Smith, DM AF Share, GH Murphy, RJ Dennis, BR Schwartz, RA Tolbert, AK Lin, RP Smith, DM TI RHESSI observation of atmospheric gamma rays from impact of solar energetic particles on 21 April 2002 SO SOLAR PHYSICS LA English DT Article AB The RHESSI high-resolution spectrometer detected gamma-ray lines and continuum emitted by the Earth's atmosphere during impact of solar energetic particles in the south polar region from 16:00-17:00 UT on 21 April 2002. The particle intensity at the time of the observation was a factor of 10-100 weaker than previous events when gamma-rays were detected by other instruments. This is the first high-resolution observation of atmospheric gamma-ray lines produced by solar energetic particles. De-excitation lines were resolved that, in part, come from N-14 at 728, 1635, 2313, 3890, and 5106 keV, and the C-12 spallation product at similar to4439 keV. Other unresolved lines were also detected. We provide best-fit line energies and widths and compare these with moderate resolution measurements by SMM of lines from an SEP event and with high-resolution measurements made by HEAO 3 of lines excited by cosmic rays. We use line ratios to estimate the spectrum of solar energetic particles that impacted the atmosphere. The 21 April spectrum was significantly harder than that measured by SMM during the 20 October 1989 shock event; it is comparable to that measured by Yohkoh on 15 July 2000. This is consistent with measurements of 10-50 MeV protons made in space at the time of the gamma-ray observations. C1 USN, Res Lab, EO Hulburt Ctr Space Res, Washington, DC 20375 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. RP Share, GH (reprint author), USN, Res Lab, EO Hulburt Ctr Space Res, Washington, DC 20375 USA. RI Dennis, Brian/C-9511-2012 NR 12 TC 12 Z9 12 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-0938 J9 SOL PHYS JI Sol. Phys. PD NOV PY 2002 VL 210 IS 1-2 BP 357 EP 372 DI 10.1023/A:1022457507830 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 644YE UT WOS:000180948200020 ER PT J AU Kontar, EP Brown, JC McArthur, GK AF Kontar, EP Brown, JC McArthur, GK TI Nonuniform target ionization and fitting thick target electron injection spectra to RHESSI data SO SOLAR PHYSICS LA English DT Article ID BREMSSTRAHLUNG; FLARES AB Past analyses of flare hard X-ray (HXR) spectra have largely ignored the effect of nonuniform ionization along the electron paths in the thick-target model, though it is very significant for well-resolved spectra. The inverse problem (photon spectrum to electron injection spectrum F-o(E-o)) is disturbingly non-unique. However, we show that it is relatively simple to allow for the effect in forward fitting of parametric models of F-o (E-0) and provide an expression to evaluate it for the usual single power-law form of F-o(E-o). The expression involves the column depth N* of the transition region in the flare loop as one of the parameters so data fitting can enable derivation of N* (and its evaporative evolution) as part of the fitting procedure. The fit to RHESSI data on four flares for a single power law F-o(E-o) is much improved when ionization structure is included compared to when the usual fully ionized approximation is used. This removes the need, in these events at least, to invoke broken power laws, or other forms, of the acceleration spectrum F-o(E-o) to explain the observed photon spectrum. C1 Univ Glasgow, Dept Phys & Astron, Astron & Astrophys Grp, Glasgow G12 8QQ, Lanark, Scotland. Catholic Univ Amer, Goddard Space Flight Ctr, Washington, DC 20064 USA. RP Kontar, EP (reprint author), Univ Glasgow, Dept Phys & Astron, Astron & Astrophys Grp, Glasgow G12 8QQ, Lanark, Scotland. RI Kontar, Eduard/B-7897-2008 OI Kontar, Eduard/0000-0002-8078-0902 NR 11 TC 40 Z9 40 U1 1 U2 1 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-0938 J9 SOL PHYS JI Sol. Phys. PD NOV PY 2002 VL 210 IS 1-2 BP 419 EP 429 DI 10.1023/A:1022494318540 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 644YE UT WOS:000180948200024 ER PT J AU Krucker, S Christe, S Lin, RP Hurford, GJ Schwartz, RA AF Krucker, S Christe, S Lin, RP Hurford, GJ Schwartz, RA TI Hard X-ray microflares down to 3 keV SO SOLAR PHYSICS LA English DT Article ID TEMPERATURE; PARAMETERS; ENERGETICS AB The excellent sensitivity, spectral and spatial resolution, and energy coverage down to 3 keV provided by the Reuven Ramaty High-Energy Solar Spectroscopic Imager mission (RHESSI) allows for the first time the detailed study of the locations and the spectra of solar microflares down to 3 keV. During a one-hour quiet interval (GOES soft X-ray level around 136) on 2 May, 1:40-2:40 UT, at least 7 microflares occurred with the largest peaking at A6 GOES level. The microflares are found to come from 4 different active regions including one behind the west limb. At 7" resolution, some events show elongated sources, while others are unresolved point sources. In the impulsive phase of the microflares, the spectra can generally be fitted better with a thermal model plus power law above similar to 6-7 keV than with a thermal only. The decay phase sometimes can be fitted with a thermal only, but in some events, power-law emission is detected late in the event indicating particle acceleration after the thermal peak of the event. The behind-the-limb microflare shows thermal emissions only, suggesting that the non-thermal power law emission originates lower, in footpoints that are occulted. The power-law fits extend to below 7 keV with exponents between -5 and -8, and imply a total non-thermal electron energy content between 10(26) - 10(27) erg. Except for the fact that the power-law indices are steeper than what is generally found in regular flares, the investigated microflares show characteristics similar to large flares. Since the total energy in non-thermal electrons is very sensitive to the value of the power law and the energy cutoff, these observations will give us better estimates of the total energy input into the corona. (Note that color versions of figures are on the accompanying CD-ROM.). C1 Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. Univ Calif Berkeley, Dept Phys, Berkeley, CA 94720 USA. NASA, Goddard Space Flight Ctr, SSAI, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. RP Krucker, S (reprint author), Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. OI Christe, Steven/0000-0001-6127-795X NR 10 TC 56 Z9 58 U1 0 U2 0 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-0938 J9 SOL PHYS JI Sol. Phys. PD NOV PY 2002 VL 210 IS 1-2 BP 445 EP 456 DI 10.1023/A:1022404512780 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 644YE UT WOS:000180948200026 ER PT J AU Van Doornik, DM AF Van Doornik, DM TI Patterns of temporal genetic variation in coho salmon: Estimates of the effective proportion of 2-year-olds in natural and hatchery populations SO TRANSACTIONS OF THE AMERICAN FISHERIES SOCIETY LA English DT Article ID SOUTHERN BRITISH-COLUMBIA; STOCK IDENTIFICATION; PACIFIC SALMON; ONCORHYNCHUS-KISUTCH; CONSERVATION GENETICS; BREEDING-BEHAVIOR; CHINOOK SALMON; DNA VARIATION; SIZE; TACTICS AB The majority of coho salmon Oncorhynchus kisutch south of central British Columbia spawn when they are 3 years old, so gene flow among brood years occurs predominately when precocious 2-year-old males (jacks) spawn successfully. To determine how much gene flow among brood years is occurring, we evaluated temporal differences in allozyme allele frequencies in four coho salmon populations in Washington State. Forty-three loci were polymorphic in the 26 samples, totaling 2,328 fish, that were collected from three naturally spawning populations and one hatchery population over 7 years. Our results indicate a greater degree of geographic variation among populations than temporal variation within populations, suggesting that population genetic analyses that depend on spatial variation can be done on natural coho salmon populations even in the absence of temporal sampling. Using a modification of the temporal method for estimating effective population size, we estimated the effective proportion of 2-year-olds to be 35% for each of the naturally spawning populations and 2% for the hatchery population. These results suggest that precocity is a viable and important life history strategy in the naturally spawning coho salmon populations we studied. C1 Natl Marine Fisheries Serv, Manchester, WA 98353 USA. NOAA, Natl Marine Fisheries Serv, NW Fisheries Sci Ctr, Seattle, WA 98112 USA. RP Van Doornik, DM (reprint author), Natl Marine Fisheries Serv, POB 130, Manchester, WA 98353 USA. NR 61 TC 11 Z9 11 U1 0 U2 0 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 NOV PY 2002 VL 131 IS 6 BP 1007 EP 1019 DI 10.1577/1548-8659(2002)131<1007:POTGVI>2.0.CO;2 PG 13 WC Fisheries SC Fisheries GA 643VE UT WOS:000180881100001 ER PT J AU Wilke, CO Adami, C AF Wilke, CO Adami, C TI The biology of digital organisms SO TRENDS IN ECOLOGY & EVOLUTION LA English DT Review ID HIGH MUTATION-RATES; DELETERIOUS MUTATIONS; SYNERGISTIC EPISTASIS; ASEXUAL POPULATIONS; ESCHERICHIA-COLI; RNA VIRUS; EVOLUTION; FITNESS; COMPLEXITY; ACCUMULATION AB Digital organisms are self-replicating computer programs that mutate and evolve. They can be thought of as a domesticated form of computer virus that lives in, and adapts to, a controlled environment. Digital organisms provide a unique opportunity with which to study evolutionary biology in a form of life that shares no ancestry with carbon-based life forms, and hence to distinguish general principles of evolution from historical accidents that are particular to biochemical life. In terms of the complexity of their evolutionary dynamics, digital organisms can be compared with biochemical viruses and bacteria. Recent studies of digital organisms have addressed long-term evolutionary adaptation and the growth of complexity in evolving systems, patterns of epistatic interactions in various genetic backgrounds, and quasi-species dynamics. C1 CALTECH, Digital Life Lab, Pasadena, CA 91125 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Wilke, CO (reprint author), CALTECH, Digital Life Lab, MC 136-93, Pasadena, CA 91125 USA. RI Adami, Christoph/A-5181-2009; Adami, Christoph/A-9675-2011; Wilke, Claus/B-4643-2008 OI Adami, Christoph/0000-0002-2915-9504; Wilke, Claus/0000-0002-7470-9261 NR 47 TC 52 Z9 52 U1 0 U2 6 PU ELSEVIER SCIENCE LONDON PI LONDON PA 84 THEOBALDS RD, LONDON WC1X 8RR, ENGLAND SN 0169-5347 J9 TRENDS ECOL EVOL JI Trends Ecol. Evol. PD NOV PY 2002 VL 17 IS 11 BP 528 EP 532 AR PII S0169-5347(02)02612-5 DI 10.1016/S0169-5347(02)02612-5 PG 5 WC Ecology; Evolutionary Biology; Genetics & Heredity SC Environmental Sciences & Ecology; Evolutionary Biology; Genetics & Heredity GA 604TV UT WOS:000178637900014 ER PT J AU Simon, MK AF Simon, MK TI A moment generating function (MGF)-based approach for performance evaluation of space-time coded communication systems SO WIRELESS COMMUNICATIONS & MOBILE COMPUTING LA English DT Article DE digital communications; fading channels; space-time coding; error probability; performance analysis ID RAYLEIGH-FADING CHANNELS; RATE WIRELESS COMMUNICATION; ERROR-PROBABILITY; BLOCK-CODES; DIVERSITY AB A few years back, a generic analysis approach referred to as the MGF method was introduced for the purpose of simplifying the evaluation of the performance of digital communication over fading channels. A particular case of high interest that fell under the umbrella of the methodology was the evaluation of the average error probability performance of systems that employ receive diversity to combat multipath as well as the possible inclusion of error-correcting coding/decoding for improving power efficiency. In this paper, we extend the methodology to space-time coded systems. Illustrative examples are explicitly given for space-time trellis coding. The emphasis of the paper is on the performance analysis tools and their application, as opposed to the design of the space-time codes themselves. Copyright (C) 2002 John Wiley Sons, Ltd. C1 CALTECH, Jet Prop Lab, Pasadena, CA USA. RP Simon, MK (reprint author), Univ Calif Los Angeles, Dept Elect Engn, Los Angeles, CA 90024 USA. NR 46 TC 19 Z9 21 U1 0 U2 1 PU JOHN WILEY & SONS INC PI HOBOKEN PA 111 RIVER ST, HOBOKEN, NJ 07030 USA SN 1530-8669 J9 WIREL COMMUN MOB COM JI Wirel. Commun. Mob. Comput. PD NOV PY 2002 VL 2 IS 7 BP 667 EP 692 DI 10.1002/wcm.81 PG 26 WC Computer Science, Information Systems; Engineering, Electrical & Electronic; Telecommunications SC Computer Science; Engineering; Telecommunications GA 625UA UT WOS:000179832900003 ER PT J AU Tabazadeh, A Djikaev, YS Hamill, P Reiss, H AF Tabazadeh, A Djikaev, YS Hamill, P Reiss, H TI Laboratory evidence for surface nucleation of solid polar stratospheric cloud particles SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID NITRIC-ACID TRIHYDRATE; LIDAR OBSERVATIONS; SULFURIC-ACID; CRYSTALLIZATION KINETICS; PHYSICAL-CHEMISTRY; OZONE HOLE; AEROSOL; WATER; H2SO4/HNO3/H2O; HNO3 AB Nitric acid-containing cloud particles, known as polar stratospheric clouds, play an important role in the springtime ozone destruction over the polar regions. Nitric acid initially condenses in the polar stratosphere to form supercooled solution droplets of mainly nitric acid and water with trace amounts of sulfuric acid. Nitric acid dihydrate (NAD) and nitric acid trihydrate (NAT) later crystallize from this supercooled solution phase to form solid polar stratospheric cloud particles. Until now, experimental data on this crystallization process has been analyzed under the assumption that NAD and NAT nucleation took place in the interior volume of a cloud droplet. However, in this paper, reanalysis of experimental data on the homogeneous freezing rates of concentrated aqueous nitric acid solution droplets provides substantial support for the occurrence of nucleation "pseudoheterogeneously" at the air-aqueous nitric acid solution interface of the droplet. Furthermore, in a following paper, theory that provides compelling evidence for such interfacial nucleation is developed. Together, the reanalysis of laboratory data in this paper and the supporting theoretical arguments in the following paper suggest that the homogeneous nucleation process occurring in atmospheric droplets may be a surface- rather than a volume-related rate process. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. San Jose State Univ, Dept Phys, San Jose, CA 95192 USA. Univ Calif Los Angeles, Dept Biochem & Chem, Los Angeles, CA 90095 USA. RP Tabazadeh, A (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 49 TC 62 Z9 62 U1 0 U2 10 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 OCT 31 PY 2002 VL 106 IS 43 BP 10238 EP 10246 DI 10.1021/jp021045k PG 9 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 608XW UT WOS:000178873900022 ER PT J AU Djikaev, YS Tabazadeh, A Hamill, P Reiss, H AF Djikaev, YS Tabazadeh, A Hamill, P Reiss, H TI Thermodynamic conditions for the surface-stimulated crystallization of atmospheric droplets SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID SOLID-LIQUID INTERFACE; MOLECULAR THEORY; NITRIC-ACID; CRYSTAL NUCLEATION; ICE NUCLEATION; SULFURIC-ACID; WAVE-CLOUDS; MELT; SIMULATIONS; CLUSTERS AB We attempt to explain the experimental and molecular dynamics simulation evidence that suggests that the freezing of atmospheric aerosols occurs beginning at the droplet surface. By using the capillarity approximation, we derive the reversible work of formation of a crystal nucleus in the cases where it forms homogeneously within a (supercooled) bulk liquid and where it forms "pseudoheterogeneously" at the surface. Comparing the works of formation in these two cases, one obtains a condition that must hold in order for pseudoheterogeneous (surface) crystallization to be thermodynamically more favorable than homogeneous (bulk) crystallization. This condition is satisfied when at least one crystal facet is only partially wettable by its own melt. C1 NASA, Ames Res Ctr, Div Earth Sci, Moffett Field, CA 94035 USA. Univ Calif Los Angeles, Dept Biochem & Chem, Los Angeles, CA 90095 USA. San Jose State Univ, Dept Phys, San Jose, CA 95192 USA. RP Djikaev, YS (reprint author), NASA, Ames Res Ctr, Div Earth Sci, MS 245-4, Moffett Field, CA 94035 USA. NR 46 TC 53 Z9 53 U1 0 U2 14 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 OCT 31 PY 2002 VL 106 IS 43 BP 10247 EP 10253 DI 10.1021/jp021044s PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 608XW UT WOS:000178873900023 ER PT J AU Cinke, M Li, J Chen, B Cassell, A Delzeit, L Han, J Meyyappan, M AF Cinke, M Li, J Chen, B Cassell, A Delzeit, L Han, J Meyyappan, M TI Pore structure of raw and purified HiPco single-walled carbon nanotubes SO CHEMICAL PHYSICS LETTERS LA English DT Article ID ADSORPTION; DECOMPOSITION; MONOXIDE; GROWTH AB Very high purity single-walled carbon nanotubes (SWNTs) were obtained from HiPco SWNT samples containing Fe particles by a two-step purification process. The raw and purified samples were characterized using high resolution transmission electron microscopy (HRTEM), Raman spectroscopy and thermogravimetric analysis (TGA). The purified sample consists of similar to0.4% Fe and the process does not seem to introduce any additional defects. The N-2 adsorption isotherm studies at 77 K reveal that the total surface area of the purified sample increases to 1587 m(2)/g from 567 m(2)/g for the raw material, which is the highest value reported for SWNTs. (C) 2002 Elsevier Science B.V. All rights reserved. C1 NASA, Ames Res Ctr, Ctr Nanotechnol, Moffett Field, CA 94035 USA. RP Li, J (reprint author), Eloret Corp, Sunnyvale, CA 94087 USA. NR 18 TC 168 Z9 168 U1 7 U2 24 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 OCT 28 PY 2002 VL 365 IS 1-2 BP 69 EP 74 AR PII S0009-2614(02)01420-3 DI 10.1016/S0009-2614(02)01420-3 PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 608FU UT WOS:000178835800010 ER PT J AU Watanabe, S Akiyama, M Ueda, Y Ohta, K Mushotzky, R Takahashi, T Yamada, T AF Watanabe, S Akiyama, M Ueda, Y Ohta, K Mushotzky, R Takahashi, T Yamada, T TI Chandra observations and optical identification of hard X-ray sources discovered with ASCA SO PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN LA English DT Article DE galaxies : active; surveys; X-rays : galaxies; X-rays : general ID MEDIUM-SENSITIVITY SURVEY; GIS CATALOG PROJECT; ROSAT DEEP SURVEY; N-LOG S; SPECTRAL PROPERTIES; GALAXIES; VARIABILITY; NUCLEI; FIELD; SKY AB We present the first results of Chandra and optical follow-up observations of hard X-ray sources detected in the ASCA Medium Sensitivity Survey (AMSS). Optical identifications were made for five objects. Three of them show either weak or absent optical narrow emission lines, and are at low redshift similar to 0.06. One of them is a broad line object at z = 0.910 and one is a z = 0.460 object with only narrow lines. All of the narrow-line objects show strong evidence of absorption in their X-ray spectra. Their line ratios are consistent with a Seyfert II/LINER identification, as are the line widths. The three low-redshift objects have the colors of normal galaxies, and apparently the light is dominated by stars. This could be due to extinction of the underlying nuclear continuum by the same matter that absorbs X-rays and/or due to dilution of the central source by starlight. These results suggest that X-ray sources that appear as "normal" galaxies in optical and near-IR bands significantly contribute to the hard X-ray background. This population of objects has a high space density, and probably dominates the entire population of active galaxies. C1 Inst Space & Astronaut Sci, Sagamihara, Kanagawa 2298510, Japan. Univ Tokyo, Dept Phys, Tokyo 1130033, Japan. Natl Astron Observ Japan, Hilo, HI 96720 USA. Kyoto Univ, Dept Astron, Kyoto 6068502, Japan. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Natl Astron Observ, Tokyo 1818588, Japan. RP Inst Space & Astronaut Sci, 3-1-1 Yoshinodai, Sagamihara, Kanagawa 2298510, Japan. EM watanabe@astro.isas.ac.jp NR 34 TC 6 Z9 6 U1 0 U2 1 PU OXFORD UNIV PRESS PI OXFORD PA GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND SN 0004-6264 EI 2053-051X J9 PUBL ASTRON SOC JPN JI Publ. Astron. Soc. Jpn. PD OCT 25 PY 2002 VL 54 IS 5 BP 683 EP 694 DI 10.1093/pasj/54.5.683 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 610PV UT WOS:000178970100008 ER PT J AU Xiang, Y Zhang, JZH Wang, DY AF Xiang, Y Zhang, JZH Wang, DY TI Semirigid vibrating rotor target model for CH4 dissociation on a Ni(111) surface SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID VIBRATIONALLY ASSISTED CHEMISORPTION; 6-DIMENSIONAL QUANTUM DYNAMICS; ATOM-DIATOM COLLISIONS; WAVE PACKET FORMALISM; MOLECULAR-BEAM; PRESSURE GAP; METHANE; H-2; ADSORPTION; ETHANE AB We present a theoretical treatment of the semirigid vibrating rotor target model to study dissociative chemisorption of CH4 at the atop site on Ni(111) surface. In this treatment, the fixed-site approximation is used to study chemisorption of methane on Ni treated as a rigid and locally flat surface. This results in a four-dimensional (4D) theoretical model to treat methane dissociation on Ni. Using parameters from ab initio calculations, an empirical potential energy surface is constructed for the CH4/Ni(111) system over the atop site. A 4D quantum dynamics calculation using the time-dependent wave-packet method is carried out on this potential energy surface. Our calculation shows that the dissociation probability of methane is an increasing function of kinetic energy, and the C-H stretching vibration significantly enhances the dissociation. The dissociation probability has a strong dependence on the initial orientation of the molecule. Reasonably good agreement is found between the current theoretical calculation and experimental results. (C) 2002 American Institute of Physics. C1 NYU, Dept Chem, New York, NY 10003 USA. NASA, Ames Res Ctr, Eloret Inst, Moffett Field, CA 94035 USA. RP Xiang, Y (reprint author), NYU, Dept Chem, New York, NY 10003 USA. RI Zhang, John/A-3372-2013 NR 55 TC 26 Z9 26 U1 0 U2 7 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0021-9606 J9 J CHEM PHYS JI J. Chem. Phys. PD OCT 22 PY 2002 VL 117 IS 16 BP 7698 EP 7704 DI 10.1063/1.1509062 PG 7 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 602AW UT WOS:000178483400032 ER PT J AU Kojima, J Nguyen, QV AF Kojima, J Nguyen, QV TI Laser pulse-stretching with multiple optical ring cavities SO APPLIED OPTICS LA English DT Article ID RAYLEIGH-LIF MEASUREMENTS; SWITCHED RUBY-LASER; INDUCED BREAKDOWN; RAMAN-SCATTERING; JET FLAMES; TEMPERATURE; TRANSMISSION; IGNITION; FRACTION AB We describe a simple and passive nanosecond-long laser-pulse stretcher using multiple optical ring cavities. We present a model of the pulse-stretching process for an arbitrary number of optical ring cavities. This new model explicitly includes the effects of cavity delay time, beam-splitter reflectivity, total number of optical cavities, and describes the effects of spatial profile sensitivity. Using the model, we optimize the design of a pulse stretcher for use in a spontaneous Raman-scattering excitation system that avoids laser-induced plasma spark problems. From the optimized design, we then experimentally demonstrate and verify the model with a three-cavity pulse-stretcher system that converts a 1000-mJ, 8.4-ns-long input laser pulse into an approximately 75-ns-long (FWHM) output laser pulse with a peak power reduction of 0.10X and an 83% efficiency. (C) 2002 Optical Society of America. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP NASA, Glenn Res Ctr, 21000 Brookpk Rd, Cleveland, OH 44135 USA. EM quang-viet.nguyen@grc.nasa.gov NR 21 TC 45 Z9 46 U1 0 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 OCT 20 PY 2002 VL 41 IS 30 BP 6360 EP 6370 DI 10.1364/AO.41.006360 PG 11 WC Optics SC Optics GA 605GF UT WOS:000178668700011 PM 12396186 ER PT J AU Williger, GM Campusano, LE Clowes, RG Graham, MJ AF Williger, GM Campusano, LE Clowes, RG Graham, MJ TI Large-scale structure at z=1.2 outlined by MgII absorbers SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmology : observations; intergalactic medium; quasars : absorption lines ID ABSORPTION-LINE SYSTEMS; LYMAN-BREAK GALAXIES; ESO/SERC FIELD-927; REDSHIFT SURVEY; FAINT GALAXIES; STAR-FORMATION; QUASARS; UNIVERSE; EVOLUTION; RADIATION AB The largest known structure in the high-redshift universe is mapped by at least 18 quasars and spans similar to5degrees x 2.degrees5 on the sky, with a quasar spatial overdensity of 6-10 times above the mean. This large quasar group provides an extraordinary laboratory similar to100 x 200 x 200 h(-3) comoving Mpc(3) in size (q(0) = 0.5, Lambda = 0, H-0 = 100 h km s(-1) Mpc(-1)) covering 1.20 < z < 1.39 in redshift. One approach to establishing how large quasar groups relate to mass (galaxy) enhancements is to probe their gas content and distribution via background quasars. We performed a survey for Mg II absorption systems in a similar to2.degrees5 x 2.degrees5 sub field in the large quasar group and found 38 absorbers to a rest equivalent width limit of W-0 = 0.3 Angstrom over 0.69 < z < 2.02. Only 24 absorbers were expected; thus, we find a 2 sigma overdensity over all redshifts in our survey. We have found the large quasar group to be associated with 11 Mg II absorption systems at 1.2 < z < 1.4; 0.02%-2.05% of simulations with random Mg II redshifts match or exceed this number in that redshift interval, depending on the normalization method used. The minimal spanning tree test also supports the existence of a structure of Mg II absorbers coincident with the large quasar group and additionally indicates a foreground structure populated by Mg II absorbers and quasars at z similar to 0.8. Finally, we find a tendency for Mg II absorbers over all redshifts in our survey to correlate with field quasars (i.e., quasars both inside and outside of the large quasar group) at a projected scale length on the sky of 9 h(-1) Mpc and a velocity difference \Delta\ = 3000-4500 km s(-1). While the correlation is on a scale consistent with observed galaxy active galactic nucleus distributions, the nonzero velocity offset could be due to the "periphery effect", in which quasars tend to populate the outskirts of clusters of galaxies and metal absorption systems, or to peculiar velocity effects. C1 NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. Natl Opt Astron Observ, Tucson, AZ 85716 USA. Univ Chile, Dept Astron, Santiago, Chile. Univ Cent Lancashire, Ctr Astrophys, Preston PR1 2HE, Lancs, England. Univ London Imperial Coll Sci Technol & Med, Blackett Lab, London SW7 2BW, England. RP Williger, GM (reprint author), Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. RI Campusano, Luis/I-5267-2016 OI Campusano, Luis/0000-0002-0057-2397 NR 57 TC 17 Z9 17 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD OCT 20 PY 2002 VL 578 IS 2 BP 708 EP 736 DI 10.1086/342614 PN 1 PG 29 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 604JR UT WOS:000178617600005 ER PT J AU Band, DL AF Band, DL TI A gamma-ray burst trigger tool kit SO ASTROPHYSICAL JOURNAL LA English DT Article DE gamma rays : bursts ID BATSE OBSERVATIONS; SPECTRA; CATALOG; BRIGHT AB The detection rate of a gamma-ray burst detector can be increased by using a count-rate trigger with many accumulation times Deltat and energy bands DeltaE. Because a burst s peak flux varies when averaged over different Deltat and DeltaE, the nominal sensitivity (the numerical value of the peak flux) of a trigger system is less important than how much fainter a burst could be at the detection threshold as Deltat and DeltaE are changed. The relative sensitivity of different triggers can be quantified by referencing the detection threshold back to the peak flux for a fiducial value of Deltat and DeltaE. This mapping between peak flux values for different sets of Deltat and DeltaE varies from burst to burst. Quantitative estimates of the burst detection rate for a given detector and trigger system can be based on the observed rate at a measured peak flux value in this fiducial trigger. Predictions of a proposed trigger s burst detection rate depend on the assumed burst population, and these predictions can be wildly in error for triggers that differ significantly from previous missions. I base the fiducial rate on the BATSE observations: 550 bursts per sky above a peak flux of 0.3 photons cm(-2) s(-1) averaged over Deltat = 1.024 s and DeltaE = 50-300 keV. Using a sample of 100 burst light curves, I find that triggering on all possible values of Deltat that are multiples of 0.064 s decreases the average threshold peak flux on the 1.024 s timescale by a factor of 0.6. Extending DeltaE to lower energies includes the large flux of the X-ray background, increasing the background count rate. Consequently, a low-energy DeltaE is advantageous only for very soft bursts. Whether a large fraction of the population of bright bursts is soft is disputed; the new population of X-ray ashes is soft but relatively faint. C1 NASA, Goddard Space Flight Ctr, GLAST SSC, Greenbelt, MD 20771 USA. RP Univ Maryland Baltimore Cty, Dept Phys, Joint Ctr Astrophys, 1000 Hilltop Circle, Baltimore, MD 21250 USA. EM dband@lheapop.gsfc.nasa.gov NR 13 TC 20 Z9 20 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-637X EI 1538-4357 J9 ASTROPHYS J JI Astrophys. J. PD OCT 20 PY 2002 VL 578 IS 2 BP 806 EP 811 DI 10.1086/342661 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 604JR UT WOS:000178617600010 ER PT J AU Mirabal, N Halpern, JP Kulkarni, SR Castro, S Bloom, JS Djorgovski, SG Galama, TJ Harrison, FA Frail, DA Price, PA Reichart, DE Ebeling, H Bunker, A Dawson, S Dey, A Spinrad, H Stern, D AF Mirabal, N Halpern, JP Kulkarni, SR Castro, S Bloom, JS Djorgovski, SG Galama, TJ Harrison, FA Frail, DA Price, PA Reichart, DE Ebeling, H Bunker, A Dawson, S Dey, A Spinrad, H Stern, D TI Time-dependent optical spectroscopy of GRB 010222: Clues to the gamma-ray burst environment SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmology : observations; galaxies : abundances; galaxies : ISM; galaxies : star clusters; gamma rays : bursts ID GALACTIC-CENTER; MASSIVE STARS; INTERSTELLAR ABUNDANCES; ABSORPTION-LINES; ATOMIC DATA; MILKY-WAY; EMISSION; DUST; SUPERNOVAE; AFTERGLOW AB We present sequential optical spectra of the afterglow of GRB 010222 obtained 1 day apart using the Low-Resolution Imaging Spectrometer (LRIS) and the Echellette Spectrograph and Imager (ESI) on the Keck Telescopes. Three low-ionization absorption systems are spectroscopically identified at z(1) = 1.47688, z(2) = 1.15628, and z(3) = 0.92747. The higher resolution ESI spectrum reveals two distinct components in the highest redshift system at z(1a) = 1.47590 and z(1b) = 1.47688. We interpret the z(1b) = 1.47688 system as an absorption feature of the disk of the host galaxy of GRB 010222. The best-fitted power-law optical continuum and [Zn/Cr] ratio imply low dust content or a local gray dust component near the burst site. In addition, we do not detect strong signatures of vibrationally excited states of H-2. If the gamma-ray burst took place in a superbubble or young stellar cluster, there are no outstanding signatures of an ionized absorber either. Analysis of the spectral time dependence at low resolution shows no significant evidence for absorption-line variability. This lack of variability is confronted with time-dependent photoionization simulations designed to apply the observed flux from GRB 010222 to a variety of assumed atomic gas densities and cloud radii. The absence of time dependence in the absorption lines implies that high-density environments are disfavored. In particular, if the GRB environment was dust free, its density was unlikely to exceed n(H) (I) = 10(2) cm(-3). If depletion of metals onto dust is similar to Galactic values or less than solar abundances are present, then n(H) (I) greater than or equal to 2 x 10(4) cm(-3) is probably ruled out in the immediate vicinity of the burst. C1 Columbia Univ, Dept Astron, New York, NY 10027 USA. CALTECH, Palomar Observ 105 24, Pasadena, CA 91125 USA. CALTECH, Ctr Infrared Proc & Anal, Pasadena, CA 91125 USA. Natl Radio Astron Observ, Socorro, NM 87801 USA. Univ Hawaii, Inst Astron, Honolulu, HI 96822 USA. Univ Cambridge, Inst Astrophys, Cambridge CB3 OHA, England. Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA. Natl Opt Astron Observ, Tucson, AZ 85719 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Mirabal, N (reprint author), Columbia Univ, Dept Astron, 550 W 120 St, New York, NY 10027 USA. RI Galama, Titus/D-1429-2014 OI Galama, Titus/0000-0002-1036-396X NR 75 TC 51 Z9 51 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD OCT 20 PY 2002 VL 578 IS 2 BP 818 EP 832 DI 10.1086/342619 PN 1 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 604JR UT WOS:000178617600012 ER PT J AU Yamasaki, NY Ohashi, T Furusho, T AF Yamasaki, NY Ohashi, T Furusho, T TI Chandra observation of the central galaxies in the A1060 cluster of galaxies SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : clusters : individual (A1060); galaxies : elliptical and lenticular, cD; galaxies : individual (NGC 3309, NGC 3311) galaxies : interactions; X-rays : galaxies ID RAY EMITTING GAS; ABELL-1060 CLUSTER; PERSEUS CLUSTER; MASS-LOSS; HOT GAS; NGC-3311; ASCA; TEMPERATURE; ROSAT; FLOWS AB A Chandra observation of the central region of the A1060 cluster of galaxies resolved X-ray emission from two giant elliptical galaxies, NGC 3311 and NGC 3309. The emission from these galaxies consists of two components, namely, the hot interstellar medium (ISM) and the low-mass X-ray binaries (LMXBs). We found that the spatial extent of the ISM component was much smaller than that of stars for both galaxies, while the ratios of X-ray to optical blue-band luminosities were rather low but within the general scatter for elliptical galaxies. After subtracting the LMXB component, the ISM is shown to be in pressure balance with the intracluster medium of A1060 at the outer boundary of the ISM. These results imply that the hot gas supplied from stellar mass loss is confined by the external pressure of the intracluster medium, with the thermal conduction likely to be suppressed. The cD galaxy NGC 3311 does not exhibit the extended potential structure that is commonly seen in bright elliptical galaxies, and we discuss the possible evolution history of the very isothermal cluster A1060. C1 Tokyo Metropolitan Univ, Dept Phys, Tokyo 1920397, Japan. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Yamasaki, NY (reprint author), Tokyo Metropolitan Univ, Dept Phys, 1-1 Minami Ohsawa, Tokyo 1920397, Japan. RI Yamasaki, Noriko/C-2252-2008 NR 39 TC 28 Z9 28 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD OCT 20 PY 2002 VL 578 IS 2 BP 833 EP 841 DI 10.1086/342652 PN 1 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 604JR UT WOS:000178617600013 ER PT J AU Owl, RCY Meixner, MM Fong, D Haas, MR Rudolph, AL Tielens, AGGM AF Owl, RCY Meixner, MM Fong, D Haas, MR Rudolph, AL Tielens, AGGM TI Testing models of low-excitation photodissociation regions with far-infrared observations of reflection nebulae SO ASTROPHYSICAL JOURNAL LA English DT Article DE dust, extinction; infrared : ISM; ISM : lines and bands; reflection nebulae ID MOLECULAR CLOUD INTERFACE; R-ASSOCIATIONS; STAR-FORMATION; RED RECTANGLE; LINE EMISSION; ORION; SUBMILLIMETER; DUST; RADIATION; NGC-2023 AB This paper presents Kuiper Airborne Observatory observations of the photodissociation regions ( PDRs) in nine reflection nebulae. These observations include the far-infrared atomic fine-structure lines of [O I] 63 and 145 mum, [C II] 158 mum, and [Si II] 35 mum and the adjacent far-infrared continuum to these lines. Our analysis of these far-infrared observations provides estimates of the physical conditions in each reflection nebula. In our sample of reflection nebulae, the stellar effective temperatures are 10,000 30,000 K, the gas densities are 4 x 10(2)-2 x 10(4) cm(-3), the gas temperatures are 200-690 K, and the incident far-ultraviolet intensities are 300-8100 times the ambient interstellar radiation field strength (1.2 x 10(-4) ergs cm(2) s(-1) sr(-1)). Our observations are compared with current theory for low-excitation PDRs. The [C II] 158 mum to [O I] 63 mum line ratio decreases with increasing incident far-ultraviolet intensity. This trend is due in part to a positive correlation of gas density with incident far-ultraviolet intensity. We show that this correlation arises from a balance of pressure between the H II region and the surrounding PDR. The [O I] 145 to 63 mum line ratio is higher ( greater than 0.1) than predicted and is insensitive to variations in incident far-ultraviolet intensity and gas density. The stellar temperature has little effect on the heating efficiency that primarily had the value 3 x 10(-3), within a factor of 2. This result agrees with a model that modifies the photoelectric heating theory to account for color temperature effects and predicts that the heating efficiencies would vary by less than a factor of 3 with the color temperature of the illuminating field. In addition to the single-pointing observations, an [O I] 63 mum scan was done across the molecular ridge of one of our sample reflection nebulae, NGC 1977. The result appears to support previous suggestions that the ionization front of this well-studied PDR is not purely edge-on. C1 Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA 90095 USA. Univ Illinois, Dept Astron, Urbana, IL 61801 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Harvey Mudd Coll, Dept Phys, Claremont, CA 91711 USA. Kapteyn Astron Inst, NL-9700 AV Groningen, Netherlands. RP Owl, RCY (reprint author), Univ Calif Los Angeles, Dept Phys & Astron, Mail Code 156205, Los Angeles, CA 90095 USA. NR 58 TC 22 Z9 22 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD OCT 20 PY 2002 VL 578 IS 2 BP 885 EP 896 DI 10.1086/342647 PN 1 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 604JR UT WOS:000178617600019 ER PT J AU Harris, WM Scherb, F Mierkiewicz, E Oliversen, R Morgenthaler, J AF Harris, WM Scherb, F Mierkiewicz, E Oliversen, R Morgenthaler, J TI Production, outflow velocity, and radial distribution of H2O and OH in the coma of comet C/1995 O1 (Hale-Bopp) from wide-field imaging of OH SO ASTROPHYSICAL JOURNAL LA English DT Article DE comets : individual (Hale-Bopp 1995 O1) ID EXPANSION VELOCITY; P/HALLEY; HALLEY; GAS; CONSTRAINTS; ATMOSPHERES; EQUATIONS; MODELS AB Observations of OH are a useful proxy of the water production rate (Q(H2O)) and outflow velocity (V-H2O) in comets. From wide-field images taken on 1997 March 28 and April 8 that capture the entire scale length of the OH coma of comet C/ 1995 O1 (Hale-Bopp), we obtain Q(OH) from the model-independent method of aperture summation and Q(H2O) from the OH photochemical branching ratio, BROH. Using an adaptive ring summation algorithm, we extract the radial brightness distribution of OH 0-0 band emission out to cometocentric distances of up to 10(6) km, both as azimuthal averages and in quadrants covering different position angles relative to the comet Sun line. These profiles are fitted using both fixed and variable velocity two-component spherical expansion models to estimate V OH with increasing distance from the nucleus. The OH coma of Hale-Bopp was more spatially extended than those of previous comets, and this extension is best matched by a variable acceleration of H2O and OH that acted across the entire coma, but was strongest within 1-2 10(4) km from the nucleus. Our models indicate that V-OH at the edge of our detectable field of view (10(6) km) was similar to2-3 times greater in Hale-Bopp than for a 1P/Halley class comet at 1 AU, which is consistent with the results of more sophisticated gas-kinetic models, extrapolation from previous observations of OH in comets with Q(H2O) > 10(29) s(-1), and direct radio measurements of the outer coma Hale-Bopp OH velocity. The likely source of this acceleration is thermalization of the excess energy of dissociation of H2O and OH over an extended collisional coma. When the coma is broken down by quadrants in position angle, we find an azimuthal asymmetry in the radial distribution that is characterized by an increase in the spatial extent of OH in the region between the orbit-trailing and anti-Sunward directions. Model fits specific to this area and comparison with radio OH measurements suggest greater acceleration here, with V-OH similar to1.5 times greater at a 10(6) km cometocentric distance than elsewhere in the coma. We discuss several mechanisms that may have acted within the coma to produce the observed effect. C1 Univ Wisconsin, Madison, WI 53706 USA. Goddard Space Flight Ctr, Greenbelt, MD USA. RP Harris, WM (reprint author), Univ Wisconsin, 1150 Univ Ave, Madison, WI 53706 USA. NR 36 TC 16 Z9 16 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD OCT 20 PY 2002 VL 578 IS 2 BP 996 EP 1008 DI 10.1086/342648 PN 1 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 604JR UT WOS:000178617600029 ER PT J AU Fixsen, DJ Dwek, E AF Fixsen, DJ Dwek, E TI The zodiacal emission spectrum as determined by COBE and its implications SO ASTROPHYSICAL JOURNAL LA English DT Article DE infrared : solar system; interplanetary medium ID INTERPLANETARY DUST CLOUD; BACKGROUND EXPERIMENT SEARCH; SOLAR-SYSTEM; FIRAS; IRAS; RADIATION; PARTICLES; COMETS; LIGHT; BELT AB We combine observations from the DIRBE and FIRAS instruments on the COBE satellite to derive an annually averaged spectrum of the zodiacal cloud in the 10 1000 l m wavelength region. The spectrum exhibits a break at similar to150 mum that indicates a sharp break in the dust size distribution at a radius of about 30 mum. The spectrum can be fitted with a single blackbody with a lambda(-2) emissivity law beyond 150 mum and a temperature of 240 K. We also used a more realistic characterization of the cloud to fit the spectrum, including a distribution of dust temperatures representing different dust compositions and distances from the Sun, as well as a realistic representation of the spatial distribution of the dust. We show that amorphous carbon and silicate dust with respective temperatures of 280 and 274 K at 1 AU, and size distributions with a break at grain radii of 14 and 32 mum, can provide a good fit to the average zodiacal dust spectrum. The total mass of the zodiacal cloud is 2-11 Eg (Eg = 10(18) g), depending on the grain composition. The lifetime of the cloud, against particle loss by Poynting-Robertson drag and the effects of solar wind, is about 10(5) yr. The required replenishment rate is similar to10(14) g yr(-1). If this is provided by the asteroid belt alone, the asteroids lifetime would be similar to3 x 10(10) yr. But comets and Kuiper belt objects may also contribute to the zodiacal cloud. C1 NASA, Goddard Space Flight Ctr, Sci Syst & Applicat Inc, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. RP Fixsen, DJ (reprint author), NASA, Goddard Space Flight Ctr, Sci Syst & Applicat Inc, Code 685, Greenbelt, MD 20771 USA. NR 28 TC 66 Z9 66 U1 1 U2 3 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD OCT 20 PY 2002 VL 578 IS 2 BP 1009 EP 1014 DI 10.1086/342658 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 604JR UT WOS:000178617600030 ER PT J AU Smith, DM Heindl, WA Swank, JH AF Smith, DM Heindl, WA Swank, JH TI Orbital and superorbital periods of 1E 1740.7-2942 and GRS 1758-258 SO ASTROPHYSICAL JOURNAL LA English DT Article DE stars : individual (GRS 1758-258, 1E 1740.7-2942); X-rays : stars ID X-RAY SOURCE; CYGNUS X-1; INFRARED COUNTERPART; ACCRETION DISCS; LMC X-3; GRS-1758-258; SEARCH; 1E-1740.7-2942; DISCOVERY; LMC-X-3 AB Five years of Rossi X-Ray Timing Explorer (RXTE) observations of the Galactic black hole candidates 1E 1740.7-2942 and GRS 1758-258 show a periodic modulation with an amplitude of 3%-4% in each source at 12.73 +/- 0.05 and 18.45 +/- 0.10 days, respectively. We interpret the modulations as orbital, suggesting that the objects have red giant companions. Combining the RXTE data with earlier data (Zhang, Harmon, & Liang) from the Burst and Transient Source Experiment on the Compton Gamma Ray Observatory, we find a long period or quasi-period of about 600 days in 1E 1740.7-2942 and a suggestion of a similar 600 day period in GRS 1758-258. These timescales are longer than any yet found for either precessing systems like Hercules X-1 and SS 433 or binaries like LMC X-3 and Cygnus X-1 with more irregular long periods. C1 Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. Univ Calif San Diego, Ctr Astrophys & Space Sci, La Jolla, CA 92093 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Smith, DM (reprint author), Univ Calif Berkeley, Space Sci Lab, Grizzly Peak Centennial Dr, Berkeley, CA 94720 USA. RI Swank, Jean/F-2693-2012 NR 33 TC 30 Z9 30 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD OCT 20 PY 2002 VL 578 IS 2 BP L129 EP L132 DI 10.1086/344701 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 604JU UT WOS:000178617800009 ER PT J AU Chaban, GM Lundell, J Gerber, RB AF Chaban, GM Lundell, J Gerber, RB TI Theoretical study of decomposition pathways for HArF and HKrF SO CHEMICAL PHYSICS LETTERS LA English DT Article ID CORRELATED MOLECULAR CALCULATIONS; SIZE-EXTENSIVE MODIFICATION; METASTABLE HELIUM COMPOUND; GAUSSIAN-BASIS SETS; RARE-GAS; VIBRATIONAL SPECTROSCOPY; ELECTRON CORRELATION; ARGON COMPOUND; AB-INITIO; CONFIGURATION AB To provide theoretical insights into the stability and dynamics of the new rare gas compounds HArF and HKrF, reaction paths for decomposition processes HRgF --> Rg + HF and HRgF --> H + Rg + F (Rg = Ar, Kr) are calculated using ab initio electronic structure methods. The bending channels, HRgF --> Rg + HF, are described by single-configurational MP2 and CCSD(T) electronic structure methods, while the linear decomposition paths, HRgF --> H + Rg + F, require the use of multi-configurational wave functions that include dynamic correlation and are size extensive. HArF and HKrF molecules are found to be energetically stable with respect to atomic dissociation products (H + Rg + F) and separated by substantial energy barriers from Rg + HF products, which ensure their kinetic stability. The results are compatible with experimental data on these systems. (C) 2002 Elsevier Science B.V. All rights reserved. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ Helsinki, Dept Chem, FIN-00014 Helsinki, Finland. Hebrew Univ Jerusalem, Dept Chem Phys, IL-91904 Jerusalem, Israel. Univ Calif Irvine, Dept Chem, Irvine, CA 92697 USA. RP Chaban, GM (reprint author), NASA, Ames Res Ctr, Mail Stop T27B-1, Moffett Field, CA 94035 USA. EM chaban@nas.nasa.gov NR 25 TC 62 Z9 62 U1 1 U2 9 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 OCT 16 PY 2002 VL 364 IS 5-6 BP 628 EP 633 AR PII S0009-2614(02)01411-2 DI 10.1016/S0009-2614(02)01411-2 PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 604PT UT WOS:000178630800032 ER PT J AU Brandt, PC Ohtani, S Mitchell, DG Fok, MC Roelof, EC Demajistre, R AF Brandt, PC Ohtani, S Mitchell, DG Fok, MC Roelof, EC Demajistre, R TI Global ENA observations of the storm mainphase ring current: Implications for skewed electric fields in the inner magnetosphere SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID MODEL; CONVECTION AB The local time distribution of the ring current in the 27119 keV range during several geomagnetic storm main phases have been investigated. The data was obtained by the high energy neutral atom (HENA) imager onboard IMAGE. Global proton distributions are derived from the observed energetic neutral atom (ENA) images using a linear inversion technique. During storms with low IMF B-y the peak of the proton distribution is around 01 MLT. For storms with high IMF B-y the peak can rotate to dawn. The rotation angle depends on solar wind velocity and interplanetary magnetic field (IMF) B-y, but less on IMF B-z. We discuss how this morphology implies the existence of strong and skewed equatorial electric fields in the inner magnetosphere. Our results are consistent with in-situ ring current measurements, radar observations and with kinetic models that self-consistently calculate the electric field produced by the closure of the partial ring current. C1 Johns Hopkins Univ, Appl Phys Lab, Laurel, MD 20723 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Johns Hopkins Univ, Appl Phys Lab, 11100 Johns Hopkins Rd, Laurel, MD 20723 USA. RI Ohtani, Shinichi/E-3914-2016; Fok, Mei-Ching/D-1626-2012; Brandt, Pontus/N-1218-2016 OI Ohtani, Shinichi/0000-0002-9565-6840; Brandt, Pontus/0000-0002-4644-0306 NR 12 TC 88 Z9 90 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 EI 1944-8007 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD OCT 15 PY 2002 VL 29 IS 20 AR 1954 DI 10.1029/2002GL015160 PG 3 WC Geosciences, Multidisciplinary SC Geology GA 639BL UT WOS:000180607700015 ER PT J AU Comiso, JC AF Comiso, JC TI A rapidly declining perennial sea ice cover in the Arctic SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID SURFACE AIR-TEMPERATURE; PASSIVE MICROWAVE; OCEAN AB The perennial sea ice cover in the Arctic is shown to be declining at -9% per decade using satellite data from 1978 to 2000. A sustained decline at this rate would mean the disappearance of the multiyear ice cover during this century and drastic changes in the Arctic climate system. An apparent increase in the fraction of second year ice in the 1990s is also inferred suggesting an overall thinning of the ice cover. Surface ice temperatures derived from satellite data are negatively correlated with perennial ice area and are shown to be increasing at the rate of 1.2 K per decade. The latter implies longer melt periods and therefore decreasing ice volume in the more recent years. C1 NASA, Goddard Space Flight Ctr, Lab Hydrospher Proc, Greenbelt, MD 20771 USA. RP Comiso, JC (reprint author), NASA, Goddard Space Flight Ctr, Lab Hydrospher Proc, Code 971, Greenbelt, MD 20771 USA. NR 22 TC 220 Z9 230 U1 4 U2 53 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD OCT 15 PY 2002 VL 29 IS 20 AR 1956 DI 10.1029/2002GL015650 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 639BL UT WOS:000180607700017 ER PT J AU Jensen, E Drdla, K AF Jensen, E Drdla, K TI Nitric acid concentrations near the tropical tropopause: Implications for the properties of tropical nitric acid trihydrate clouds SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID LOWER STRATOSPHERE; REACTIVE NITROGEN; COLD TEMPERATURES; UPPER TROPOSPHERE; CHEMISTRY; MODEL; DEHYDRATION; AEROSOLS; MISSION; ICE AB [1] In situ measurements of NOy, NOx, and temperature confirm that nitric acid trihydrate (NAT) particles could form at the tropical tropopause. The HNO3 mixing ratio near the tropical tropopause is typically no larger than about 0.2- 0.3 ppbv, and the corresponding equilibrium mass of nitric acid trihydrate (NAT) is no larger than 0.3 mug m(-3). Considerably larger NAT condensed masses are required to explain the HALOE extinctions; however, localized regions of enhanced HNO3 produced by oxidation of lightning- generated NO might exist. NAT layers would only be identified as clouds by SAGE II if the particle diameters are in the optimum range of about 0.6 to 2 mum and the condensed NAT mass is larger than about 0.2 mug m(-3). The SAGE II extinction ratio measurements (0.5 mum/ 1.0 mum) cannot distinguish NAT clouds from mixtures of optically thin ice clouds and background aerosols. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Jensen, E (reprint author), NASA, Ames Res Ctr, MS 245-4, Moffett Field, CA 94035 USA. NR 20 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 OCT 15 PY 2002 VL 29 IS 20 AR 2001 DI 10.1029/2002GL015190 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 639BL UT WOS:000180607700062 ER PT J AU Thompson, AM Witte, JC Freiman, MT Phahlane, NA Coetzee, GJR AF Thompson, AM Witte, JC Freiman, MT Phahlane, NA Coetzee, GJR TI Lusaka, Zambia, during SAFARI-2000: Convergence of local and imported ozone pollution SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article AB [1] In August and September, throughout south central Africa, seasonal clearing of dry vegetation and other fire-related activities lead to intense smoke haze and ozone formation. The first ozone soundings in the heart of the southern African burning region were taken at Lusaka, Zambia (15.5S, 28E) in early September 2000. Maximum surface ozone was over 90 ppbv and column tropospheric ozone exceeded 50 DU. These values are higher than concurrent measurements over Nairobi (1S, 38E) and Irene (25S, 28E, near Pretoria). At least 30% of Lusaka surface ozone appears to be from local sources. A layer at 800-500 hPa has ozone >120 ppbv and originates from transboundary recirculation. Starting out over Zambia, Angola, and Namibia, ozone-rich air travels east to the Indian Ocean, before heading back toward Mozambique, Zimbabwe and Zambia. Thus, Lusaka collects local and imported pollution, consistent with its location within the southern African gyre. C1 NASA, SSAI, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Witwatersrand, Climatol Res Grp, ZA-2050 Wits, Johannesburg, South Africa. S African Weather Serv, ZA-0001 Pretoria, South Africa. RP Thompson, AM (reprint author), NASA, SSAI, Goddard Space Flight Ctr, Code 916, Greenbelt, MD 20771 USA. RI Thompson, Anne /C-3649-2014 OI Thompson, Anne /0000-0002-7829-0920 NR 14 TC 13 Z9 13 U1 1 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD OCT 15 PY 2002 VL 29 IS 20 AR 1976 DI 10.1029/2002GL015399 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 639BL UT WOS:000180607700037 ER PT J AU Gerber, RB Brauer, B Gregurick, SK Chaban, GM AF Gerber, RB Brauer, B Gregurick, SK Chaban, GM TI Calculation of anharmonic vibrational spectroscopy of small biological molecules SO PHYSCHEMCOMM LA English DT Article ID SELF-CONSISTENT-FIELD; DENSITY-FUNCTIONAL THEORY; DIFFUSION MONTE-CARLO; AB-INITIO; EMPIRICAL POTENTIALS; ELECTRONIC-STRUCTURE; N-METHYLACETAMIDE; WAVE-FUNCTIONS; POLYATOMIC SYSTEMS; REMPI SPECTROSCOPY AB The role of anharmonic effects in the vibrational spectroscopy of small biological molecules and their 1:1 complexes with water is discussed. The strengths and limitations of the vibrational self-consistent field (VSCF) method and its extensions as a computational tool for this purpose are examined. Anharmonic coupling between different vibrational modes is found to be very important for these systems, even for fundamental transitions, and incorporation of these effects seems essential for quantitative interpretation of experimental data. Both analytical, empirical force fields, and potential surfaces computed from electronic structure methods are used in VSCF calculations of several benchmark systems and compared with experimental spectroscopic data. Glycine in several conformers, the glycine water complex, and N-methylacetamide are among the systems discussed. The main conclusions are: (1) Electronic structure methods such as MP2/DZP and density functional B97, give very good agreement with experimental data. Thus, MP2 and B97 clearly provide an accurate description of the anharmonic interactions. VSCF calculations, including all modes, with MP2, B97 and other successful methods are presently feasible for molecules with up to 15-20 atoms. (2) The electronic structure methods seem to give spectroscopic predictions in much better accord with experiment than standard empirical force fields such as AMBER or OPLS. The anharmonic couplings provided by these methods differ greatly, in the cases tested to date, from the ab initio ones. The implications of these results for future modeling of small biomolecules are discussed. Comments are provided on future directions in this subject, including extensions to large biomolecules. C1 Hebrew Univ Jerusalem, Dept Phys Chem, IL-91904 Jerusalem, Israel. Hebrew Univ Jerusalem, Fritz Haber Res Ctr, IL-91904 Jerusalem, Israel. Univ Calif Irvine, Dept Chem, Irvine, CA 92697 USA. Univ Maryland Baltimore Cty, Dept Chem & Biochem, Baltimore, MD 20215 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Gerber, RB (reprint author), Hebrew Univ Jerusalem, Dept Phys Chem, IL-91904 Jerusalem, Israel. NR 62 TC 38 Z9 39 U1 1 U2 4 PU ROYAL SOC CHEMISTRY PI CAMBRIDGE PA THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND SN 1460-2733 J9 PHYSCHEMCOMM JI PhysChemComm PD OCT 15 PY 2002 VL 5 BP 142 EP 150 DI 10.1039/b208000a PG 9 WC Chemistry, Physical SC Chemistry GA 611PY UT WOS:000179028000001 ER PT J AU Wilson, JW Ramamurthy, R Porwollik, S McClelland, M Hammond, T Allen, P Ott, CM Pierson, DL Nickerson, CA AF Wilson, JW Ramamurthy, R Porwollik, S McClelland, M Hammond, T Allen, P Ott, CM Pierson, DL Nickerson, CA TI Microarray analysis identifies Salmonella genes belonging to the low-shear modeled microgravity regulon SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article ID ACID TOLERANCE RESPONSE; TYPHIMURIUM VIRULENCE; POLYACRYLAMIDE GELS; FUR; ASSEMBLIES; TISSUES AB The low-shear environment of optimized rotation suspension culture allows both eukaryotic and prokaryotic cells to assume physiologically relevant phenotypes that have led to significant advances in fundamental investigations of medical and biological importance. This culture environment has also been used to model microgravity for ground-based studies regarding the impact of space flight on eukaryotic and prokaryotic physiology. We have previously demonstrated that low-shear modeled microgravity (LSMMG) under optimized rotation suspension culture is a novel environmental signal that regulates the virulence, stress resistance, and protein expression levels of Salmonella enterica serovar Typhimurium. However, the mechanisms used by the cells of any species, including Salmonella, to sense and respond to LSMMG and identities of the genes involved are unknown. In this study, we used DNA microarrays to elucidate the global transcriptional response of Salmonella to LSMMG. When compared with identical growth conditions under normal gravity (1 x g), LSMMG differentially regulated the expression of 163 genes distributed throughout the chromosome, representing functionally diverse groups including transcriptional regulators, virulence factors, lipopolysaccharide biosynthetic enzymes, iron-utilization enzymes, and proteins of unknown function. Many of the LSMMG-regulated genes were organized in clusters or operons. The microarray results were further validated by RT-PCR and phenotypic analyses, and they indicate that the ferric uptake regulator is involved in the LSMMG response. The results provide important insight about the Salmonella LSMMG response and could provide clues for the functioning of known Salmonella virulence systems or the identification of uncharacterized bacterial virulence strategies. C1 Tulane Univ, Sch Med, Dept Microbiol & Immunol, Program Mol Pathogenesis & Immun, New Orleans, LA 70112 USA. NASA, Life Sci Res Labs, Houston, TX 77058 USA. NASA, EASI Wyle Labs, Houston, TX 77058 USA. Vet Affairs Med Ctr, New Orleans, LA 70112 USA. Tulane Univ, Med Ctr, Nephrol Sect, New Orleans, LA 70112 USA. Sidney Kimmel Canc Ctr, Dept Cell & Mol Biol, San Diego, CA 92121 USA. RP Nickerson, CA (reprint author), Tulane Univ, Sch Med, Dept Microbiol & Immunol, Program Mol Pathogenesis & Immun, New Orleans, LA 70112 USA. RI McClelland, Michael/A-8583-2011; OI McClelland, Michael/0000-0003-1788-9347 FU NIAID NIH HHS [R01 AI 34829-14, R01 AI034829] NR 23 TC 83 Z9 94 U1 0 U2 5 PU NATL ACAD SCIENCES PI WASHINGTON PA 2101 CONSTITUTION AVE NW, WASHINGTON, DC 20418 USA SN 0027-8424 J9 P NATL ACAD SCI USA JI Proc. Natl. Acad. Sci. U. S. A. PD OCT 15 PY 2002 VL 99 IS 21 BP 13807 EP 13812 DI 10.1073/pnas.212387899 PG 6 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 604RW UT WOS:000178635700084 PM 12370447 ER PT J AU Harris, JD Eckles, WE Hepp, AF Duraj, SA Fanwick, PE AF Harris, JD Eckles, WE Hepp, AF Duraj, SA Fanwick, PE TI Synthesis and characterization of anionic transition metal isothiocyanate complexes prepared from metal powders and thiourea SO INORGANICA CHIMICA ACTA LA English DT Article DE thiocyanate; isothiocyanate; methylpyridine; picoline; coordination; crystal structures ID CHEMICAL-VAPOR-DEPOSITION; SINGLE-SOURCE PRECURSORS; THIN-FILMS; CRYSTAL; 4-METHYLPYRIDINE; THIOCYANATE; HOST AB Three new isothiocyanate-4-methylpyridine anionic compounds were prepared by refluxing metal powders (Mn, Fe, and Cu) with thiourea in 4-methylpyridine (gamma-picoline). The isothiocyanate ligand is believed to be generated in situ by the isomerization of thiourea to NH4+SCN- at reflux temperatures. The complexes (HPic)(2)[Mn(NCS)(4)(Pic)(2)].2pic (1), (HPic)(2)[Fe(NCS)(4)(Pic)(2)].2pic (2), and (Hpic)[Cu(NCS)(3)(PiC)(2)].PiC (3) (where pic = gamma-picoline) were characterized by single crystal X-ray crystallography. Compounds 1 and 2 are isostructural with four equatorially bound isothiocyanate ligands and two axially bound gamma-picoline molecules. Compound 3 is a five-coordinate Cu(II) molecule with a distorted square pyramidal geometry. Coordinated picoline and two isothiocyanates form the basal plane and the remaining isothiocyanate is bound at the apex. The structural data for compounds 1, 2, and 3 are presented. Published by Elsevier Science B.V. C1 Cleveland State Univ, Dept Chem, Cleveland, OH 44115 USA. NASA, Glenn Res Ctr, Thin Film Technol Grp, Cleveland, OH 44135 USA. Purdue Univ, Dept Chem, W Lafayette, IN 47907 USA. RP Hepp, AF (reprint author), Cleveland State Univ, Dept Chem, Cleveland, OH 44115 USA. NR 19 TC 16 Z9 16 U1 1 U2 4 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0020-1693 J9 INORG CHIM ACTA JI Inorg. Chim. Acta PD OCT 14 PY 2002 VL 338 BP 99 EP 104 AR PII S0020-1693(02)00903-9 DI 10.1016/S0020-1693(02)00903-9 PG 6 WC Chemistry, Inorganic & Nuclear SC Chemistry GA 607JA UT WOS:000178787400013 ER PT J AU Rinehart, SA Houck, JR Smith, JD Wilson, JC AF Rinehart, SA Houck, JR Smith, JD Wilson, JC TI Mid-infrared spectroscopy of protoplanetary and planetary nebulae SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE astrochemistry; techniques : spectroscopic; ISM : lines and bands; planetary nebulae : general; infrared : ISM ID WC CENTRAL STARS; SPECTROGRAPH; ABUNDANCES; EVOLUTION; FEATURES; OBJECTS; SPECTRA AB We present medium-resolution (R similar to 600), mid-infrared (7.5-14 mum) spectra of 15 young planetary nebulae. Linestrengths for observed forbidden transitions are presented, and numerous broad emission features from silicates, polyaromatic hydrocarbons (PAHs) and silicon carbide (SiC) are observed. C1 Cornell Univ, Ithaca, NY 14853 USA. Univ London Queen Mary & Westfield Coll, London E1 4NS, England. RP Rinehart, SA (reprint author), NASA, Goddard Space Flight Ctr, Mail Code 631, Greenbelt, MD 20771 USA. NR 33 TC 7 Z9 7 U1 0 U2 0 PU BLACKWELL PUBLISHING LTD PI OXFORD PA 9600 GARSINGTON RD, OXFORD OX4 2DG, OXON, ENGLAND SN 0035-8711 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD OCT 11 PY 2002 VL 336 IS 1 BP 66 EP 72 DI 10.1046/j.1365-8711.2002.05707.x PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 600CT UT WOS:000178373600011 ER PT J AU Snyder, LE Lovas, FJ Mehringer, DM Miao, NY Kuan, YJ Hollis, JM Jewell, PR AF Snyder, LE Lovas, FJ Mehringer, DM Miao, NY Kuan, YJ Hollis, JM Jewell, PR TI Confirmation of interstellar acetone SO ASTROPHYSICAL JOURNAL LA English DT Article DE ISM : abundances; ISM : clouds; ISM : individual (Sagittarius B2(N-LMH)); ISM : molecules; radio lines : ISM ID MOLECULAR LINE OBSERVATIONS; STAR-FORMING REGIONS; ASTROPHYSICAL INTEREST; MICROWAVE-SPECTRA; SAGITTARIUS B2; MILLIMETER; SUBMILLIMETER; RESOLUTION; CHEMISTRY; HCOOCH3 AB We present new observations of interstellar acetone [(CH3)(2) CO] from both the NRAO 12 m and the BIMA array. We report NRAO 12 m detections of 13 new acetone emission features that can be assigned to 20 acetone transitions. These assignments are based on the measured and calculated frequencies in 2002 of Groner and coworkers, and they confirm the interstellar acetone identification in 1987 by Combes and coworkers. In addition, our BIMA array observations show that acetone emission is concentrated in the vicinity of the hot molecular core Sgr B2 (N-LMH). The beam-averaged column density for acetone is [N-T] = 2.9(3) x 10(16) cm(-2). This value is consistent with the 1990 conclusions of Herbst, Giles, & Smith that the observed acetone abundance is too high to be explained by gas-phase synthesis reactions. C1 Univ Illinois, Dept Astron, Urbana, IL 61801 USA. NASA, Goddard Space Flight Ctr, Earth & Space Data Comp Div, Greenbelt, MD 20771 USA. Natl Radio Astron Observ, Green Bank, WV 24944 USA. RP Snyder, LE (reprint author), Univ Illinois, Dept Astron, 1002 W Green St, Urbana, IL 61801 USA. NR 38 TC 54 Z9 54 U1 0 U2 3 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD OCT 10 PY 2002 VL 578 IS 1 BP 245 EP 255 DI 10.1086/342273 PN 1 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 598XH UT WOS:000178301500021 ER PT J AU Contreras, CS Sahai, R de Paz, AG AF Contreras, CS Sahai, R de Paz, AG TI Physical structure of the proto planetary nebula CRL 618. I. Optical long-slit spectroscopy and imaging SO ASTROPHYSICAL JOURNAL LA English DT Article DE circumstellar matter; planetary nebulae : individual (CRL 618); reflection nebulae; stars : AGB and post-AGB; stars : mass loss; stars : winds, outflows ID MASS-LOSS RATES; MOLECULAR OUTFLOW; BIPOLAR OUTFLOW; EVOLVED STARS; PROTOPLANETARY NEBULAE; RADIO-CONTINUUM; AFGL-618; CRL-618; JETS; EMISSION AB In this paper we present optical long-slit spectroscopy and imaging of the proto planetary nebula CRL 618. The optical lobes of CRL 618 consist of shock-excited gas, which emits many recombination and forbidden lines, and dust, which scatters light from the innermost regions. From the analysis of the scattered Halpha emission, we derive a nebular inclination of i = 24degrees +/- 6degrees. The spectrum of the innermost part of the east lobe (visible as a bright, compact nebulosity close to the star in the Halpha Hubble Space Telescope image) is remarkably different from that of the shocked lobes but similar to that of the inner H II region, suggesting that this region represents the outermost parts of the latter. We find a nonlinear radial variation of the gas velocity along the lobes. The largest projected LSR velocities (with respect to the systemic velocity), similar to80 km s(-1), are measured at the tips of the lobes, where the direct images show the presence of compact bow-shaped structures. The velocity of the shocks in CRL 618 is in the range similar to75-200 km s(-1), as derived from diagnostic line ratios and line profiles. We report a brightening ( weakening) of [O III] lambda5007 ([O I] lambda6300) over the last similar to10 years that may indicate a recent increase in the speed of the exciting shocks. From the analysis of the spatial variation of the nebular extinction, we find a large density contrast between the material inside the lobes and beyond them: the optical lobes seem to be cavities excavated in the asymptotic giant branch (AGB) envelope by interaction with a more tenuous post-AGB wind. The electron density, with a mean value n(e) similar to5 x 10(3)-10(4) cm(-3), shows significant fluctuations but no systematic decrease along the lobes, in agreement with most line emission arising in a thin shell of shocked material ( the lobe walls) rather than in the post-AGB wind filling the interior of the lobes. The masses of atomic and ionized gas, respectively, in the east (west) lobe are >1.3 x 10(4) (>7 x 10(-5)) and similar to6 x 10(-5) (similar to4 x 10(-5)) M.. The shocks in CRL 618 are in a radiative regime and may lead in the future to the evolution of the optically emitting lobes into a fast, bipolar molecular outflow. The time required by the dense, shocked gas to cool down significantly is less than or similar to2 yr, which is substantially lower than the kinematical age of the lobes (less than or similar to180 yr). This result suggests that a fast wind is currently active in CRL 618 and keeps shocking the circumstellar material. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. CALTECH, NASA IPAC Extragalact Database, Pasadena, CA 91125 USA. RP Contreras, CS (reprint author), CALTECH, Jet Prop Lab, MS 183-900,4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Sanchez-Contreras, Carmen/N-3718-2015; OI Sanchez-Contreras, Carmen/0000-0002-6341-592X; Gil de Paz, Armando/0000-0001-6150-2854 NR 52 TC 30 Z9 30 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD OCT 10 PY 2002 VL 578 IS 1 BP 269 EP 289 PN 1 PG 21 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 598XH UT WOS:000178301500023 ER PT J AU Im, M Yamada, T Tanaka, I Kajisawa, M AF Im, M Yamada, T Tanaka, I Kajisawa, M TI A hyper extremely red object in the field near 53W002 SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmology : observations; early universe; galaxies : formation; galaxies : high-redshift; galaxies : individual (HERO J171411.91+501541.8) ID HUBBLE DEEP FIELD; NEAR-INFRARED OBSERVATIONS; STAR-FORMATION; GALAXY; DUSTY; POPULATION; REDSHIFT; CAMERA; IMAGE; EPOCH AB Hyper extremely red objects (HEROs) are objects that are very red in near-IR colors (J-K greater than or similar to 3). They are speculated to be intrinsically red galaxies at z greater than or similar to 2 or Lyman break galaxies at z > 10. We report the discovery of a HERO in the field that includes a known radio galaxy, 53W002, and a possible cluster of galaxies both at z = 2.39. The HERO, which we name HERO J171411.91+501541.8, or 53W002-HERO1 for brevity, is visible in the Hubble Space Telescope Near-Infrared Camera and Multi-Object Spectrometer H-band data and deep K'-band data from the Subaru Telescope (K' similar or equal to 21.5 mag) but not visible in B-, V-, I-, and J-band images (J-K > 4.45, 2 sigma). Its spectral energy distribution is consistent with that of a dusty star- forming or old galaxy at z similar or equal to 2.4, which may suggest that 53W002-HERO1 is a member of the group of galaxies associated with 53W002. Alternatively, the HERO could be at z similar or equal to 12.5, if its red color is due to the redshifted Lyman break. If 53W002- HERO1 is an old galaxy at z similar to 2.4, the implied stellar age is similar to2- 3 Gyr, meaning that stars in the HERO formed at the reionization epoch of z greater than or similar to 10. C1 CALTECH, Jet Prop Lab, SIRTF Sci Ctr, IPAC, Pasadena, CA 91125 USA. Natl Astron Observ, Tokyo 181, Japan. RP Im, M (reprint author), CALTECH, Jet Prop Lab, SIRTF Sci Ctr, IPAC, 4800 Oak Grove Dr, Pasadena, CA 91125 USA. RI Im, Myungshin/B-3436-2013 OI Im, Myungshin/0000-0002-8537-6714 NR 50 TC 14 Z9 14 U1 1 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD OCT 10 PY 2002 VL 578 IS 1 BP L19 EP L22 DI 10.1086/344475 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 598XQ UT WOS:000178302200005 ER PT J AU Kazanas, D Georganopoulos, M Mastichiadis, A AF Kazanas, D Georganopoulos, M Mastichiadis, A TI The "supercritical pile" model for gamma-ray bursts: Getting the nu F-nu peak at 1 MeV SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; line : formation; radiative transfer; X-rays : general ID EMISSION; BATSE; SPECTRUM; BLAZARS; ORIGIN AB We propose that the internal energy of the gamma-ray burst (GRB) blast waves, thought to be stored in the form of relativistic protons comoving with the blast wave, is converted explosively (i.e., on light crossing timescales) into relativistic electrons of the same Lorentz factor, which are responsible for the production of observed prompt gamma-ray emission of the burst. This conversion is the result of the combined effects of the reflection of photons produced within the flow by upstream located matter, their reinterception by the blast wave, and their eventual conversion into e(+)e(-) pairs in interactions with the relativistic protons of the blast wave (via the pgamma --> pe(+)p(-) reaction). This entire procedure is contingent on two conditions on the relativistic protons: a kinematic one imposed by the threshold of the pgamma --> pe(+)e(-) reaction and a dynamic one related to the column density of the postshock matter to the same process. This latter condition is in essence identical to that of the criticality of a nuclear pile, hence the terminology. It is argued that the properties of relativistic blast waves operating under these conditions are consistent with GRB phenomenology, including the recently found correlation between quiescence periods and subsequent flare fluence. Furthermore, it is shown that, when operating near threshold, the resulting GRB spectrum produces its peak luminosity at an energy (in the lab frame) E similar or equal to m(e)c(2), thereby providing an answer to this outstanding question of GRBs. C1 NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. Univ Athens, Dept Astron, Athens, Greece. RP Kazanas, D (reprint author), NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Code 661, Greenbelt, MD 20771 USA. NR 18 TC 21 Z9 21 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD OCT 10 PY 2002 VL 578 IS 1 BP L15 EP L18 DI 10.1086/344518 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 598XQ UT WOS:000178302200004 ER PT J AU Sterling, NC Dinerstein, HL Bowers, CW AF Sterling, NC Dinerstein, HL Bowers, CW TI Discovery of enhanced germanium abundances in planetary nebulae with the Far Ultraviolet Spectroscopic Explorer SO ASTROPHYSICAL JOURNAL LA English DT Article DE line : identification; nuclear reactions, nucleosynthesis, abundances planetary nebulae : general; planetary nebulae : individual (BD+30 degrees 3639, IC 4593, NGC 3132, SwSt 1); stars : AGB and post-AGB; ultraviolet : ISM ID ASYMPTOTIC GIANT BRANCH; S-PROCESS ABUNDANCES; MOLECULAR-HYDROGEN; HEAVY-ELEMENTS; ZETA-OPHIUCHI; BAND SYSTEM; STARS; NUCLEOSYNTHESIS; ABSORPTION; TABLE AB We report the discovery of Ge III lambda1088.46 in the planetary nebulae (PNe) SwSt 1, BD +30degrees3639, NGC 3132, and IC 4593, observed with the Far Ultraviolet Spectroscopic Explorer. This is the first astronomical detection of this line and the first measurement of Ge (Z = 32) in PNe. We estimate Ge abundances using S and Fe as reference elements, for a range of assumptions about gas-phase depletions. The results indicate that Ge, which is synthesized in the initial steps of the s-process and therefore can be self-enriched in PNe, is enhanced by factors of greater than or equal to3-10. The strongest evidence for enrichment is seen for PNe with Wolf-Rayet central stars, which are likely to contain heavily processed material. C1 Univ Texas, Dept Astron, Austin, TX 78712 USA. NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. RP Sterling, NC (reprint author), Univ Texas, Dept Astron, 1 Univ Stn C1400, Austin, TX 78712 USA. NR 29 TC 29 Z9 29 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD OCT 10 PY 2002 VL 578 IS 1 BP L55 EP L58 DI 10.1086/344473 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 598XQ UT WOS:000178302200013 ER PT J AU Titarchuk, L AF Titarchuk, L TI Effects of resonance in quasi-periodic oscillators of neutron star binaries SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; stars : individual (GX 5-1, GX 17+2, GX 340+0, Scorpius X-1, 4U 0614+09, 4U 1728-34); stars : neutron ID X-RAY BINARIES; Z-SOURCE GX-340+0; FREQUENCY; FEATURES; MODEL; 4U-1728-34; DISCOVERY AB Using a large quantity of Rossi X-Ray Timing Explorer data presented in the literature, I offer a detailed investigation into the accuracy of the quasi-periodic oscillation (QPO) frequency determination. The QPO phenomenon seen in X-ray binaries is possibly a result of the resonance of the intrinsic (eigen) oscillations and harmonic driving forces of the system. I show that the resonances, in the presence of the damping of oscillations, occur at frequencies that are systematically and randomly shifted with respect to the eigenfrequencies of the system. The shift value strongly depends on the damping rate that is measured by the half-width of the QPO feature. Taking into account this effect, I analyze the QPO data for four Z sources, Scorpius X-1, GX 340+0, GX 5-1, and GX 17+2, and two atoll sources, 4U 1728-34 and 4U 0614+09. The transition-layer model (TLM) predicts the existence of the invariant quantity delta, an inclination angle of the magnetospheric axis with respect to the normal to the disk. I calculate delta and the error bars of delta using the resonance shift, and I find that the inferred delta-values are consistent with constants for these four Z sources, in which horizontal-branch oscillation and kilohertz frequencies have been detected and correctly identified. It is shown that the inferred delta are in the range between 5.degrees5 and 6.degrees5. I conclude that the TLM seems to be compatible with the data. C1 George Mason Univ, Ctr Earth Observing & Space Res Sci & Technol 1, Fairfax, VA 22030 USA. USN, Res Lab, Washington, DC 20375 USA. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Titarchuk, L (reprint author), George Mason Univ, Ctr Earth Observing & Space Res Sci & Technol 1, Fairfax, VA 22030 USA. NR 30 TC 21 Z9 22 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD OCT 10 PY 2002 VL 578 IS 1 BP L71 EP L74 DI 10.1086/344499 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 598XQ UT WOS:000178302200017 ER PT J AU Geser, A Middeldorp, A Ohlebusch, E Zantema, H AF Geser, A Middeldorp, A Ohlebusch, E Zantema, H TI Relative undecidability in term rewriting I. The termination hierarchy SO INFORMATION AND COMPUTATION LA English DT Article DE term rewriting; termination; undecidability ID SYSTEMS; RULE AB For a hierarchy of properties of term rewriting systems related to termination we prove relative undecidability: For implications X double right arrow Y in the hierarchy the property X is undecidable for term rewriting systems satisfying Y. For most implications we obtain this result for term rewriting systems consisting of a single rewrite rule. (C) 2002 Elsevier Science (USA). C1 NASA, Langley Res Ctr, ICASE, Hampton, VA 23681 USA. Univ Tsukuba, Inst Informat Sci & Elect, Tsukuba, Ibaraki 3058573, Japan. Univ Bielefeld, Fac Technol, D-33501 Bielefeld, Germany. Eindhoven Univ Technol, Dept Comp Sci, NL-5600 MB Eindhoven, Netherlands. RP NASA, Langley Res Ctr, ICASE, Mail Stop 132C, Hampton, VA 23681 USA. NR 27 TC 6 Z9 6 U1 0 U2 1 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0890-5401 EI 1090-2651 J9 INFORM COMPUT JI Inf. Comput. PD OCT 10 PY 2002 VL 178 IS 1 BP 101 EP 131 DI 10.1006/inco.2002.3120 PG 31 WC Computer Science, Theory & Methods; Mathematics, Applied SC Computer Science; Mathematics GA 608LG UT WOS:000178847400005 ER PT J AU Geser, A Middeldorp, A Ohlebusch, E Zantema, H AF Geser, A Middeldorp, A Ohlebusch, E Zantema, H TI Relative undecidability in term rewriting II. The confluence hierarchy SO INFORMATION AND COMPUTATION LA English DT Article DE term rewriting; confluence; undecidability ID FINITELY PRESENTED MONOIDS; SYSTEMS; TERMINATION; REDUCTIONS AB For a hierarchy of properties of term rewriting systems related to confluence we prove relative undecidability, i.e., for implications X double right arrow Y in the hierarchy the property X is undecidable for term rewriting systems satisfying Y. For some of the implications either X or -X is semi-decidable, for others neither X nor -X is semi-decidable. We prove most of these results for linear term rewrite Systems. (C) 2002 Elsevier Science (USA). C1 NASA, Langley Res Ctr, ICASE, Hampton, VA 23681 USA. Univ Tsukuba, Inst Informat Sci & Elect, Tsukuba, Ibaraki 3058573, Japan. Univ Bielefeld, Fac Technol, D-33501 Bielefeld, Germany. Eindhoven Univ Technol, Dept Comp Sci, NL-5600 MB Eindhoven, Netherlands. RP NASA, Langley Res Ctr, ICASE, Mail Stop 132C, Hampton, VA 23681 USA. NR 20 TC 4 Z9 4 U1 0 U2 1 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0890-5401 EI 1090-2651 J9 INFORM COMPUT JI Inf. Comput. PD OCT 10 PY 2002 VL 178 IS 1 BP 132 EP 148 DI 10.1006/inco.2002.3150 PG 17 WC Computer Science, Theory & Methods; Mathematics, Applied SC Computer Science; Mathematics GA 608LG UT WOS:000178847400006 ER PT J AU Robinson, JA Amsbury, DL Liddle, DA Evans, CA AF Robinson, JA Amsbury, DL Liddle, DA Evans, CA TI Astronaut-acquired orbital photographs as digital data for remote sensing: spatial resolution SO INTERNATIONAL JOURNAL OF REMOTE SENSING LA English DT Article ID SPACE-SHUTTLE; LANDSAT AB Astronaut-acquired orbital photographs (astronaut photographs) are a useful complement to images taken by orbiting satellites. They are in the public domain, and have been particularly useful for scientists in developing countries, as supplementary low-cloud data, and for studies requiring large numbers of images. Depending on camera, lens and look angle, digitized astronaut photographs can have pixel sizes representing areas on the Earth as small as 10 m or less, although most photographs suitable for digital remote sensing have pixel sizes between 30 m and 60 m. The objective of this paper is to provide a practical reference for scientists in a variety of disciplines who want to use astronaut photographs as remote sensing data. The characteristics of astronaut photography systems that influence spatial resolution are detailed and previous image acquisitions relative to these elements are summarized. Methods are presented for estimating ground coverage under three different levels of assumptions, to meet accuracy needs of different users. Of the more than 375000 photographs taken to date, at least half have the potential to be used as a source of digital remote sensing data. C1 NASA, Earth Sci & Image Anal Lab, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. Lockheed Martin Space Operat, Houston, TX 77058 USA. RP Robinson, JA (reprint author), NASA, Earth Sci & Image Anal Lab, Lyndon B Johnson Space Ctr, 2400 NASA Rd 1,C23, Houston, TX 77058 USA. OI Robinson, Julie/0000-0002-6832-6459 NR 61 TC 17 Z9 17 U1 1 U2 4 PU TAYLOR & FRANCIS LTD PI ABINGDON PA 4 PARK SQUARE, MILTON PARK, ABINGDON OX14 4RN, OXON, ENGLAND SN 0143-1161 J9 INT J REMOTE SENS JI Int. J. Remote Sens. PD OCT 10 PY 2002 VL 23 IS 20 BP 4403 EP 4438 DI 10.1080/01431160110107798 PG 36 WC Remote Sensing; Imaging Science & Photographic Technology SC Remote Sensing; Imaging Science & Photographic Technology GA 599MC UT WOS:000178337700016 ER PT J AU Gamba, P Houshmand, B AF Gamba, P Houshmand, B TI Joint analysis of SAR, LIDAR and aerial imagery for simultaneous extraction of land cover, DTM and 3D shape of buildings SO INTERNATIONAL JOURNAL OF REMOTE SENSING LA English DT Article ID INTERFEROMETRIC SAR; MODELS; CLASSIFICATION; ENVIRONMENTS; ALGORITHMS AB What information maybe extracted over urban area by means of joint analysis of two-dimensional (2D) and three-dimensional (3D) remote sensing data? We exploit aerial, Synthetic Aperture Radar (SAR) and Laser Induced Detection and Ranging (LIDAR) data to characterize precisely the Presidio area in San Francisco. We discriminate between different objects in the scene using their 2D and 3D characteristics. The final product of the analysis is a set of raster or vector information layers providing land covers, 3D building shapes and Digital Terrain Models (DTMs) of the Presidio. This paper investigates the relative merits of the collected data in retrieving each of these information layers, and examines how automatic algorithms to extract land cover, Digital Terrain Model (DTM) and 3D building shape could be integrated in a processing chain. C1 Univ Pavia, Dept Elect, I-27100 Pavia, Italy. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Gamba, P (reprint author), Univ Pavia, Dept Elect, Via Ferrata 1, I-27100 Pavia, Italy. RI Gamba, Paolo/G-1959-2010 OI Gamba, Paolo/0000-0002-9576-6337 NR 20 TC 30 Z9 31 U1 0 U2 11 PU TAYLOR & FRANCIS LTD PI ABINGDON PA 4 PARK SQUARE, MILTON PARK, ABINGDON OX14 4RN, OXON, ENGLAND SN 0143-1161 J9 INT J REMOTE SENS JI Int. J. Remote Sens. PD OCT 10 PY 2002 VL 23 IS 20 BP 4439 EP 4450 DI 10.1080/01431160110114952 PG 12 WC Remote Sensing; Imaging Science & Photographic Technology SC Remote Sensing; Imaging Science & Photographic Technology GA 599MC UT WOS:000178337700017 ER PT J AU Chaniotis, AK Poulikakos, D Koumoutsakos, P AF Chaniotis, AK Poulikakos, D Koumoutsakos, P TI Remeshed smoothed particle hydrodynamics for the simulation of viscous and heat conducting flows SO JOURNAL OF COMPUTATIONAL PHYSICS LA English DT Article ID CONVECTION-DIFFUSION EQUATIONS; NAVIER-STOKES EQUATIONS; SPH; VISCOSITY; VORTEX; CAVITY; NUMBER AB We present an extension of the classical scheme. of smoothed particle hydrodynamics (SPH) for the accurate handling of diffusion terms in the momentum and energy equation of viscous and heat conducting flows. A key aspect of the present SPH approach is the periodic reinitialization (remeshing) of the particle locations, which are being distorted by the flow map. High-order moment conserving kernels are being implemented for this remeshing procedure leading to accurate simulations. The accuracy of the proposed SPH methodology is tested for a number of benchmark problems involving flow and energy transport. The results demonstrate that the proposed SPH methodology is capable of DNS quality simulations while maintaining its robustness and adaptivity. (C) 2002 Elsevier Science (USA). C1 Swiss Fed Inst Technol, Lab Thermodynam Emerging Technol, Inst Energy Technol, Zurich, Switzerland. NASA, Ames Res Ctr, Ctr Turbulence Res, Moffett Field, CA 94035 USA. RP Chaniotis, AK (reprint author), Swiss Fed Inst Technol, Lab Thermodynam Emerging Technol, Inst Energy Technol, Zurich, Switzerland. RI Koumoutsakos, Petros/A-2846-2008; poulikakos, dimos/O-2853-2014 OI Koumoutsakos, Petros/0000-0001-8337-2122; poulikakos, dimos/0000-0001-5733-6478 NR 33 TC 95 Z9 101 U1 0 U2 11 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0021-9991 J9 J COMPUT PHYS JI J. Comput. Phys. PD OCT 10 PY 2002 VL 182 IS 1 BP 67 EP 90 DI 10.1006/jcph.2002.7152 PG 24 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA 614HV UT WOS:000179183200004 ER PT J AU Loncar, M Yoshie, T Scherer, A Gogna, P Qiu, YM AF Loncar, M Yoshie, T Scherer, A Gogna, P Qiu, YM TI Low-threshold photonic crystal laser SO APPLIED PHYSICS LETTERS LA English DT Article ID NEAR-INFRARED WAVELENGTHS AB We have fabricated photonic crystal nanocavity lasers, based on a high-quality factor design that incorporates fractional edge dislocations. Lasers with InGaAsP quantum well active material emitting at 1550 nm were optically pumped with 10 ns pulses, and lased at threshold pumping powers below 220 muW, the lowest reported for quantum-well based photonic crystal lasers, to our knowledge. Polarization characteristics and lithographic tuning properties were found to be in excellent agreement with theoretical predictions. (C) 2002 American Institute of Physics. C1 CALTECH, Dept Elect Engn, Pasadena, CA 91125 USA. CALTECH, Jet Prop Lab, In Situ Technol & Expt Syst Sect, Pasadena, CA 91109 USA. RP Loncar, M (reprint author), CALTECH, Dept Elect Engn, MS 136-93, Pasadena, CA 91125 USA. RI Yoshie, Tomoyuki/C-3567-2008 NR 10 TC 214 Z9 220 U1 4 U2 21 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD OCT 7 PY 2002 VL 81 IS 15 BP 2680 EP 2682 DI 10.1063/1.1511538 PG 3 WC Physics, Applied SC Physics GA 599DG UT WOS:000178318400002 ER PT J AU Brillson, LJ Tumakha, S Jessen, GH Okojie, RS Zhang, M Pirouz, P AF Brillson, LJ Tumakha, S Jessen, GH Okojie, RS Zhang, M Pirouz, P TI Thermal and doping dependence of 4H-SiC polytype transformation SO APPLIED PHYSICS LETTERS LA English DT Article AB We have observed characteristic temperatures, anneal times, and doping densities that lead to stacking faults and 3C-SiC-like bands in 4H-SiC epilayers. Low energy cathodoluminescence spectroscopy measurements reveal a temperature threshold of 800 degreesC for emergence of these features in thermally oxidized or argon annealed 4H-SiC with an activation energy approximate to2.5 eV. Stacking fault generation and polytype transformation exhibits a strong doping dependence, appearing only in a range of highly doped n-type 4H-SiC. Systematics of these strain and/or electronic effects induced by high N concentrations can be used to control structural instabilities during SiC device fabrication. (C) 2002 American Institute of Physics. C1 Ohio State Univ, Dept Elect Engn, Columbus, OH 43210 USA. NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. Case Western Reserve Univ, Cleveland, OH 44106 USA. RP Brillson, LJ (reprint author), Ohio State Univ, Dept Elect Engn, Columbus, OH 43210 USA. NR 11 TC 29 Z9 29 U1 0 U2 7 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0003-6951 J9 APPL PHYS LETT JI Appl. Phys. Lett. PD OCT 7 PY 2002 VL 81 IS 15 BP 2785 EP 2787 DI 10.1063/1.1512816 PG 3 WC Physics, Applied SC Physics GA 599DG UT WOS:000178318400037 ER PT J AU Park, C Ounaies, Z Watson, KA Crooks, RE Smith, J Lowther, SE Connell, JW Siochi, EJ Harrison, JS Clair, TLS AF Park, C Ounaies, Z Watson, KA Crooks, RE Smith, J Lowther, SE Connell, JW Siochi, EJ Harrison, JS Clair, TLS TI Dispersion of single wall carbon nanotubes by in situ polymerization under sonication SO CHEMICAL PHYSICS LETTERS LA English DT Article AB Single wall nanotube reinforced polyimide nanocomposites were synthesized by in situ polymerization of monomers of interest in the presence of sonication. This process enabled uniform dispersion of single wall carbon nanotube (SWNT) bundles in the polymer matrix. The resultant SWNT-polyimide nanocomposite films were electrically conductive (antistatic) and optically transparent with significant conductivity enhancement (10 orders of magnitude) at a very low loading (0.1 vol%). Mechanical properties as well as thermal stability were also improved with the incorporation of the SWNT. (C) 2002 Elsevier Science B.V. All rights reserved. C1 NASA, Langley Res Ctr, ICASE, Adv Mat & Proc Branch, Hampton, VA 23681 USA. NASA, Langley Res Ctr, Lockheed Martin, Adv Mat & Proc Branch, Hampton, VA 23681 USA. RP Park, C (reprint author), NASA, Langley Res Ctr, ICASE, Adv Mat & Proc Branch, Mail Stop 226,6 W Taylor St, Hampton, VA 23681 USA. OI Connell, Terry/0000-0002-2676-8363 NR 17 TC 524 Z9 539 U1 14 U2 109 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 OCT 4 PY 2002 VL 364 IS 3-4 BP 303 EP 308 AR PII S0009-2614(02)01326-X DI 10.1016/S0009-2614(02)01326-X PG 6 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 603JB UT WOS:000178554900016 ER PT J AU Haldemann, AFC Baumgartner, ET Bearman, GH Blaney, DL Brown, DI Dolgin, BP Dorsky, LI Huntsberger, TL Ksendzov, A Mahoney, JC McKelvey, MJ Pavri, BE Post, GA Tubbs, EF Arvidson, RE Snider, NO Squyres, SW Gorevan, S Klingelhofer, G Bernhardt, B Gellert, R AF Haldemann, AFC Baumgartner, ET Bearman, GH Blaney, DL Brown, DI Dolgin, BP Dorsky, LI Huntsberger, TL Ksendzov, A Mahoney, JC McKelvey, MJ Pavri, BE Post, GA Tubbs, EF Arvidson, RE Snider, NO Squyres, SW Gorevan, S Klingelhofer, G Bernhardt, B Gellert, R TI FIDO science payload simulating the Athena Payload SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article DE Rover; mobility; in situ instruments; integrated payload; FIDO; Mars ID MARS AB The Jet Propulsion Laboratory's Field Integrated Development and Operations rover (FIDO) emulates and tests operational rover capabilities for advanced Mars rover missions, such as those originally planned for the Mars Surveyor 2001 Rover and currently planned for the Athena Payload on the Mars Exploration Rovers scheduled for launch in 2003. This paper describes FIDO's science instrument payload, which is fully integrated with rover hardware and software. Remote science teams visualize instrument suite data and generate FIDO commands using the Web Interface for Telescience. FIDO's instrument suite has been used in terrestrial laboratory and field tests to simulate Mars operations, to train Mars scientists, and to improve Mars rover mission science operations protocols. The payload includes a deck-mounted, stowable mast that is deployed for acquisition of stereo imaging and spectral reflectance data. The mast head houses Pancam, Navcam (the navigation camera stereo pair), and the Infrared Point Spectrometer (IPS). Pancam is a three-band, false-color infrared (0.65, 0.74, 0.855 mum) stereo imaging system. The three wavelengths were chosen to yield information on the ferric nature of observed minerals. IPS acquires spectral radiance information over the wavelengths from 1.3 to 2.5 mum (spectral resolution similar to13 cm(-1)). A 4-degree-of-freedom arm is included on the front of FIDO. The arm end effector is the mounting point for a Color Microscopic Imager and an Fe-57 Mossbauer Spectrometer. FIDO also carries a MiniCorer, which is an Athena prototype rock drill that can acquire 0.5-cm-diameter by up to 1.7-cm-long cores. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Washington Univ, Dept Earth & Planetary Sci, St Louis, MO 63130 USA. Cornell Univ, Ctr Radiophys & Space Res, Ithaca, NY 14853 USA. Honeybee Robot Inc, New York, NY 10012 USA. Univ Mainz, Inst Inorgan & Analyt Chem, D-55099 Mainz, Germany. RP Haldemann, AFC (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 23 TC 6 Z9 6 U1 0 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD OCT 4 PY 2002 VL 107 IS E11 AR 8006 DI 10.1029/2001JE001738 PG 19 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 639RR UT WOS:000180643500001 ER PT J AU Frendi, A Nesman, T Wang, TS AF Frendi, A Nesman, T Wang, TS TI On the effect of time scaling on the noise radiated by an engine plume SO JOURNAL OF SOUND AND VIBRATION LA English DT Letter ID SUPERSONIC JET NOISE C1 Univ Alabama, Dept Aerosp Engn & Mech, Huntsville, AL 35899 USA. NASA, Marshall Space Flight Ctr, Huntsville, AL 35899 USA. RP Frendi, A (reprint author), Univ Alabama, Dept Aerosp Engn & Mech, Huntsville, AL 35899 USA. NR 21 TC 2 Z9 2 U1 0 U2 0 PU ACADEMIC PRESS LTD ELSEVIER SCIENCE LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 0022-460X J9 J SOUND VIB JI J. Sound Vibr. PD OCT 3 PY 2002 VL 256 IS 5 BP 969 EP 979 DI 10.1006/jvsi.4226 PG 11 WC Acoustics; Engineering, Mechanical; Mechanics SC Acoustics; Engineering; Mechanics GA 618KM UT WOS:000179417300010 ER PT J AU Howard, SK Gaba, DM Rosekind, MR Zarcone, VP AF Howard, SK Gaba, DM Rosekind, MR Zarcone, VP TI The risks and implications of excessive daytime sleepiness in resident physicians SO ACADEMIC MEDICINE LA English DT Article ID DEPRIVATION; PERFORMANCE; DISORDERS AB Purpose. To assess the levels of physiologic and subjective sleepiness in residents in three conditions: (1) during a normal (baseline) work schedule, (2) after an in-hospital 24-hour on-call period, and (3) following a period of extended sleep. Method. In 1996, a within-subjects, repeated-measures study was performed with a volunteer sample of 11 anesthesia residents from the Stanford University School of Medicine using three separate experimental conditions. Sixteen residents were recruited and 11 of the 16 completed the three separate experimental conditions. Daytime sleepiness was assessed using the Multiple Sleep Latency Test (MSLT). Results. MSLT scores were shorter in the baseline (6-7 min) and post-call (4.9 min) conditions, compared with the extended-sleep condition (12 min, p = .0001) and there was no significant difference between the baseline and post-call conditions (p = .07). There was a significant main effect for both condition (p = .0001) and time of day (p = .0003). Subjects were inaccurate in subjectively identifying sleep onset compared with EEG measures (incorrect on 49% of EEG-determined sleep episodes). Conclusion. Residents' daytime sleepiness in both baseline and post-call conditions was near or below levels associated with clinical sleep disorders. Extending sleep time resulted in normal levels of daytime sleepiness. The residents were subjectively inaccurate determining EEG-defined sleep onset. Based on the findings from this and other studies, reforms of residents' work and duty hours are justified. C1 VA Palo Alto Hlth Care Syst, Patient Safety Ctr Inquiry, Palo Alto, CA 94304 USA. Stanford Univ, Sch Med, Dept Anesthesia, Stanford, CA 94305 USA. NASA, Ames Res Ctr, Fatigue Countermeasures Program, Ames, IA USA. RP Howard, SK (reprint author), VA Palo Alto Hlth Care Syst, Patient Safety Ctr Inquiry, 112A,3801 Miranda Ave, Palo Alto, CA 94304 USA. OI Howard, Steven/0000-0001-6475-1792 NR 29 TC 91 Z9 100 U1 0 U2 1 PU HANLEY & BELFUS INC PI PHILADELPHIA PA 210 S 13TH ST, PHILADELPHIA, PA 19107 USA SN 1040-2446 J9 ACAD MED JI Acad. Med. PD OCT PY 2002 VL 77 IS 10 BP 1019 EP 1025 DI 10.1097/00001888-200210000-00015 PG 7 WC Education, Scientific Disciplines; Health Care Sciences & Services SC Education & Educational Research; Health Care Sciences & Services GA 617MP UT WOS:000179365700013 PM 12377678 ER PT J AU Huang, XJ Kuhn, GH Nesterov, VN Averkiev, BB Penn, B Antipin, MY Timofeeva, TV AF Huang, XJ Kuhn, GH Nesterov, VN Averkiev, BB Penn, B Antipin, MY Timofeeva, TV TI (E)-(4-hydroxyphenyl)(4-nitro-phenyl)diazene, (E)-(4-methoxyphenyl)(4-nitrophenyl)diazene and (E)-[4-(6-bromohexyloxy)phenyl](4-cyanophenyl)diazene SO ACTA CRYSTALLOGRAPHICA SECTION C-STRUCTURAL CHEMISTRY LA English DT Article ID NONLINEAR-OPTICAL PROPERTIES; AZOBENZENE LIQUID-CRYSTAL; POLYMER-FILMS; GRATINGS; DICYANOVINYLBENZENE; DERIVATIVES AB Syntheses and X-ray structural investigations have been carried out for (E)-(4-hydroxyphenyl)(4-nitrophenyl)diazene, C12H9N3O3, (Ia), (E)-(4-methoxyphenyl)(4-nitrophenyl)diazene, C13H11N3O3, (IIIa), and (E)-[4-(6-bromohexyloxy)phenyl](4-cyanophenyl)diazene, C19H20BrN3O, (IIIc). In all of these compounds, the molecules are almost planar and the azobenzene core has a trans geometry. Compound (Ia) contains four and compound (IIIc) contains two independent molecules in the asymmetric unit, both in space group P (1) over bar (No. 2). In compound (Ia), the independent molecules are almost identical, whereas in crystal (IIIc), the two independent molecules differ significantly due to different conformations of the alkyl tails. In the crystals of (Ia) and (IIIa), the molecules are arranged in almost planar sheets. In the crystal of (IIIc), the molecules are packed with a marked separation of the azobenzene cores and alkyl tails, which is common for the solid crystalline precursors of mesogens. C1 New Mexico Highlands Univ, Dept Chem, Las Vegas, NM 87701 USA. Russian Acad Sci, Inst Organoelement Cpds, Moscow, Russia. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Nesterov, VN (reprint author), New Mexico Highlands Univ, Dept Chem, Las Vegas, NM 87701 USA. EM vlad@kremlin.nmhu.edu NR 23 TC 9 Z9 9 U1 0 U2 0 PU WILEY-BLACKWELL PI HOBOKEN PA 111 RIVER ST, HOBOKEN 07030-5774, NJ USA SN 0108-2701 EI 1600-5759 J9 ACTA CRYSTALLOGR C JI Acta Crystallogr. Sect. C-Struct. Chem. PD OCT PY 2002 VL 58 BP O624 EP O628 DI 10.1107/S010827010201627X PN 10 PG 5 WC Chemistry, Multidisciplinary; Crystallography SC Chemistry; Crystallography GA 600PM UT WOS:000178399800032 PM 12359949 ER PT J AU Forsythe, EL Maxwell, DL Pusey, M AF Forsythe, EL Maxwell, DL Pusey, M TI Vapor diffusion, nucleation rates and the reservoir to crystallization volume ratio SO ACTA CRYSTALLOGRAPHICA SECTION D-BIOLOGICAL CRYSTALLOGRAPHY LA English DT Article; Proceedings Paper CT 9th International Conference on the Crystallization of Biological Macromolecules CY MAR 23-28, 2002 CL JENA, GERMANY DE vapor diffusion; nucleation kinetics; lysozyme; concanavalin a; equilibration rate ID WATER EQUILIBRATION; PROTEIN CRYSTALLIZATION; DEPENDENCE; SPACE AB In a classical vapor diffusion crystallization, the protein solution is mixed in a 1: 1 ratio with the reservoir solution, containing one or more precipitant species, after which the two are placed in an enclosed chamber. As the vapor pressure is lower for the reservoir solution, due to its higher solute concentration, there is a net transfer of water through the vapor phase from the protein droplet to the reservoir. In theory, the initial conditions in the droplet are such that the protein is in either a metastable or undersaturated state with respect to crystal nucleation. The loss of water serves to both concentrate the protein and the precipitant concentrations within the drop, bringing the protein past the metastable point to nucleation. The equilibration rate is a function of the precipitant(s) used, their concentration, the temperature, the distance between the two surfaces, and the droplet to reservoir volume ratio. For a given reservoir volume smaller droplets equilibrate faster, the rate being inversely linear with the droplet volume. In attempts to maximize the number of crystallization trials, and as crystals in the 100 - 200 mm size range are sufficient, it has currently become standard practice to use starting droplet volumes of 2 - 4 mul, with reservoir volumes typically in the 200 to 500 ml range. The equilibration rates are maximized, and for most common salt concentrations and higher concentrations of polyethylene glycol (PEG) and 2-methyl-2,4-pentanediol (MPD) one can reasonably estimate that equilibration has occurred within 3 to 6 days at room temperature. Crystals appearing after this time are essentially grown under batch conditions. We experimentally find that altering the reservoir to droplet volume ratio, by changing the reservoir volume, from 50: 1 (high ratio) to 5: 1 (low ratio), on average increases the equilibration time by approximately 50% when tested with solutions of 50% MPD, 1.5 M NaCl, or 30% PEG400. However, experiments with two proteins, chicken egg white lysozyme and concanavalin a, showed an unexpected trend of slightly faster nucleation and larger crystals in the lowest ratio experiments. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. Univ Space Res Assoc, Huntsville, AL 35805 USA. RP Pusey, M (reprint author), NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. NR 18 TC 19 Z9 19 U1 1 U2 5 PU BLACKWELL MUNKSGAARD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0907-4449 J9 ACTA CRYSTALLOGR D JI Acta Crystallogr. Sect. D-Biol. Crystallogr. PD OCT PY 2002 VL 58 SI 1 BP 1601 EP 1605 DI 10.1107/S0907444902014208 PN 10 PG 5 WC Biochemical Research Methods; Biochemistry & Molecular Biology; Biophysics; Crystallography SC Biochemistry & Molecular Biology; Biophysics; Crystallography GA 597YH UT WOS:000178248000021 PM 12351870 ER PT J AU Otalora, F Garcia-Ruiz, JM Carotenuto, L Castagnolo, D Novella, ML Chernov, AA AF Otalora, F Garcia-Ruiz, JM Carotenuto, L Castagnolo, D Novella, ML Chernov, AA TI Lysozyme crystal growth kinetics in microgravity SO ACTA CRYSTALLOGRAPHICA SECTION D-BIOLOGICAL CRYSTALLOGRAPHY LA English DT Article; Proceedings Paper CT 9th International Conference on the Crystallization of Biological Macromolecules CY MAR 23-28, 2002 CL JENA, GERMANY ID ATOMIC-FORCE MICROSCOPY; PROTEIN CRYSTAL; IN-SITU; TETRAGONAL LYSOZYME; SURFACE-MORPHOLOGY; REAL-TIME; MACROMOLECULAR CRYSTALLIZATION; CANAVALIN CRYSTALLIZATION; CONCENTRATION GRADIENT; MOLECULAR RESOLUTION AB Mach-Zehnder interferometry is applied to quantitatively characterize growth of lysozyme crystals in microgravity. Experiments were performed by the Free Interface Diffusion technique into APCF FID reactors using large seeds. Tracking of the experiments using interferometry allowed to monitor the onset of supersaturation and the seed growth. A large and stable concentration depletion zone around the growing crystal developed, whose time evolution was analyzed. The interferograms were analyzed taking into account finite thickness of the cell by integrating the concentration over the straight lines through the optical path. It was concluded that there may be a quasi-steady state growth mode at the stage when the spacial concentration distribution did not change but its absolute value over all the cell was slowly diminishing. From this portion of the data, an estimate was made of the dimensionless parameter betaR/D where beta is the face kinetic coefficient, R is the effective crystal size and D is the lysozyme diffusivity in solution, as followed from the steady state model. For the assumed quasi steady state data portion, the parameter varies between 0.7 and 0.9 suggesting mixed diffusion-interface kinetic controlled growth. C1 IACT, Lab Estudios Crystalog, Fac Ciencias, Granada 18002, Spain. Mars Ctr SCARL, Naples, Italy. NASA, George C Marshall Space Flight Ctr, Univ Space Res Assoc, Huntsville, AL 35812 USA. RP Otalora, F (reprint author), IACT, Lab Estudios Crystalog, Fac Ciencias, Campus Fuentenueva, Granada 18002, Spain. RI Otalora, Fermin/L-5477-2015; Garcia-Ruiz, Juan Manuel/C-4389-2015; Otalora, Femin/F-2759-2017 OI Garcia-Ruiz, Juan Manuel/0000-0002-4743-8718; NR 69 TC 16 Z9 16 U1 1 U2 7 PU BLACKWELL MUNKSGAARD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0907-4449 J9 ACTA CRYSTALLOGR D JI Acta Crystallogr. Sect. D-Biol. Crystallogr. PD OCT PY 2002 VL 58 SI 1 BP 1681 EP 1689 DI 10.1107/S0907444902014476 PN 10 PG 9 WC Biochemical Research Methods; Biochemistry & Molecular Biology; Biophysics; Crystallography SC Biochemistry & Molecular Biology; Biophysics; Crystallography GA 597YH UT WOS:000178248000037 PM 12351886 ER PT J AU Chernyshova, M Lusakowska, E Domukhovski, V Grasza, K Szczerbakow, A Wrotek, S Kowalczyk, L Story, T Smits, CJP Swagten, HJM De Jonge, WJM Palosz, W Sipatov, AY Volobuev, VV AF Chernyshova, M Lusakowska, E Domukhovski, V Grasza, K Szczerbakow, A Wrotek, S Kowalczyk, L Story, T Smits, CJP Swagten, HJM De Jonge, WJM Palosz, W Sipatov, AY Volobuev, VV TI Magnetic and structural properties of EuS-PbS multilayers grown on n-PbS (100) substrates SO ACTA PHYSICA POLONICA A LA English DT Article; Proceedings Paper CT 31st International School on Pysics of Semiconduction Compounds CY JUN 07-14, 2002 CL JASZOWIEC, POLAND AB Magnetic properties of semiconductor EuS(t)-PbS(d)-EuS(t) ferromagnetic trilayers (t = 30 divided by 300 Angstrom and d = 7.5 divided by 70 Angstrom) grown on n-type monocrystalline PbS (100) substrate were studied by SQUID magnetometry and ferromagnetic resonance technique yielding, in particular, the dependence of the ferromagnetic Curie temperature on the thickness of the EuS layer. Structural parameters of layers were examined by X-ray powder diffraction analysis. A high structural quality of the substrate and the multilayer was verified by the measurements of the X-ray rocking curve width indicating the values of the order of 100 arcsec and by atomic force microscopy revealing the presence on the cleft PbS surface regions practically flat in the atomic scale over the area of 1 x 0.1 mum(2). C1 Polish Acad Sci, Inst Phys, PL-02668 Warsaw, Poland. Eindhoven Univ Technol, Dept Appl Phys, Ctr NanoMat, NL-5600 MB Eindhoven, Netherlands. Eindhoven Univ Technol, COBRA Res Inst, NL-5600 MB Eindhoven, Netherlands. NASA, George C Marshall Space Flight Ctr, Univ Space Res Assoc, Huntsville, AL 35812 USA. Natl Tech Univ, KPI, UA-61002 Kharkov, Ukraine. RP Chernyshova, M (reprint author), Polish Acad Sci, Inst Phys, Al Lotnikow 32-46, PL-02668 Warsaw, Poland. NR 8 TC 5 Z9 5 U1 1 U2 2 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 OCT-NOV PY 2002 VL 102 IS 4-5 BP 609 EP 615 PG 7 WC Physics, Multidisciplinary SC Physics GA 615ND UT WOS:000179251900012 ER PT J AU Noor, AK AF Noor, AK TI New links for learning in a changing profession SO AEROSPACE AMERICA LA English DT Article C1 Old Dominion Univ, NASA Langley, Ctr Adv Engn Environm, Norfolk, VA 23529 USA. RP Noor, AK (reprint author), Old Dominion Univ, NASA Langley, Ctr Adv Engn Environm, Norfolk, VA 23529 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0740-722X J9 AEROSPACE AM JI Aerosp. Am. PD OCT PY 2002 VL 40 IS 10 BP 28 EP + PG 6 WC Engineering, Aerospace SC Engineering GA 602FE UT WOS:000178494500011 ER PT J AU Morrison, D AF Morrison, D TI Astrobiology - Exploring the living universe SO AIAA JOURNAL LA English DT Article; Proceedings Paper CT AIAA 39th Aerospace Sciences Meeting and Exhibits CY JAN 08-11, 2001 CL RENO, NEVADA SP Amer Inst Aeronaut & Astronaut AB The new discipline of astrobiology, the study of life in the universe, addresses fundamental questions: Where did we come from? Are we alone in the universe? What is our future beyond the Earth? New capabilities in biotechnology, informatics, and space exploration provide the tools to address these questions. NASA has encouraged this new discipline by organizing workshops and technical meetings, establishing a NASA Astrobiology Institute, providing research funds to individual investigators, ensuring that astrobiology goals are incorporated in NASA flight missions, and initiating a program of public outreach and education. This paper describes the primary scientific goals of astrobiology at its inception, drawn from the NASA Astrobiology Roadmap. C1 NASA, Ames Res Ctr, Astrobiol Inst, Moffett Field, CA 94035 USA. RP Morrison, D (reprint author), NASA, Ames Res Ctr, Astrobiol Inst, MS 200-7, Moffett Field, CA 94035 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091 USA SN 0001-1452 J9 AIAA J JI AIAA J. PD OCT PY 2002 VL 40 IS 10 BP 1921 EP 1925 DI 10.2514/2.1530 PG 5 WC Engineering, Aerospace SC Engineering GA 600YW UT WOS:000178420200001 ER PT J AU Blank, CE Cady, SL Pace, NR AF Blank, CE Cady, SL Pace, NR TI Microbial composition of near-boiling silica-depositing thermal springs throughout Yellowstone National Park SO APPLIED AND ENVIRONMENTAL MICROBIOLOGY LA English DT Article ID HOT-SPRINGS; NEW-ZEALAND; NORTH-ISLAND; THERMOPHILIC BACTERIA; SPECIES COMPOSITION; ARCHAEAL DIVERSITY; DNA-SEQUENCES; PRECIPITATION; COMMUNITY; MATS AB The extent of hyperthermophilic microbial diversity associated with siliceous sinter (geyserite) was characterized in seven near-boiling silica-depositing springs throughout Yellowstone National Park using environmental PCR amplification of small-subunit rRNA genes (SSU rDNA), large-subunit rDNA, and the internal transcribed spacer (ITS). We found that Thermocrinis ruber, a member of the order Aquificales, is ubiquitous, an indication that primary production in these springs is driven by hydrogen oxidation. Several other lineages with no known close relatives were identified that branch among the hyperthermophilic bacteria. Although they all branch deep in the bacterial tree, the precise phylogenetic placement of many of these lineages is unresolved at this time. While some springs contained a fair amount of phylogenetic diversity, others did not. Within the same spring, communities in the subaqueous environment were not appreciably different than those in the splash zone at the edge of the pool, although a greater number of phylotypes was found along the pool's edge. Also, microbial community composition appeared to have little correlation with the type of sinter morphology. The number of cell morphotypes identified by fluorescence in situ hybridization and scanning electron microscopy was greater than the number of phylotypes in SSU clone libraries. Despite little. variation in Thermocrinis ruber SSU sequences, abundant variation was found in the hypervariable ITS region. The distribution of ITS sequence types appeared to be correlated with distinct morphotypes of Thermocrinis ruber in different pools. Therefore, species- or subspecies-level divergences are present but not detectable in highly conserved SSU sequences. C1 Univ Calif Berkeley, Dept Plant & Microbial Biol, Berkeley, CA 94720 USA. Univ Colorado, Boulder, CO 80309 USA. NASA, Ames Res Ctr, Exobiol Branch, Moffett Field, CA 94035 USA. Portland State Univ, Dept Geol, Portland, OR 97207 USA. RP Blank, CE (reprint author), Washington Univ, Dept Earth & Planetary Sci, Campus Box 1169,1 Brookings Dr, St Louis, MO 63130 USA. NR 34 TC 100 Z9 105 U1 0 U2 14 PU AMER SOC MICROBIOLOGY PI WASHINGTON PA 1752 N ST NW, WASHINGTON, DC 20036-2904 USA SN 0099-2240 J9 APPL ENVIRON MICROB JI Appl. Environ. Microbiol. PD OCT PY 2002 VL 68 IS 10 BP 5123 EP 5135 DI 10.1128/AEM.68.10.5123-5135.2002 PG 13 WC Biotechnology & Applied Microbiology; Microbiology SC Biotechnology & Applied Microbiology; Microbiology GA 600FX UT WOS:000178380900054 PM 12324363 ER PT J AU Muriel, H Quintana, H Infante, L Lambas, DG Way, MJ AF Muriel, H Quintana, H Infante, L Lambas, DG Way, MJ TI Velocity dispersions and cluster properties in the Southern Abell Redshift Survey clusters. II. SO ASTRONOMICAL JOURNAL LA English DT Article DE galaxies : clusters : general; galaxies : distances and redshifts; surveys ID GALAXY CLUSTERS; RICH CLUSTERS; PROFILES; SUBSTRUCTURE; TEMPERATURE; CATALOG; ASCA AB We report an analysis of the dynamical structure of clusters of galaxies from a survey of photometric and spectroscopic observations in the fields of southern Abell clusters. We analyze the galaxy velocity field in extended regions up to 7 h(-1) Mpc from cluster centers, and we estimate mean velocity dispersions and their radial dependence. Only one from a total of 41 Abell clusters does not correspond to a dynamically bound system. However, four of these bound objects are double clusters. We estimate that 20% (seven clusters) of the 35 remaining are subject to serious projection effects. Normalizing the clustercentric distances by means of the overdensity radius r(200), and the velocity dispersion profiles (VDPs) by the corresponding mean cluster velocity dispersion, we computed the average VDP. Our results indicate a at behavior of the mean VDP at large distances from the cluster center. Nevertheless, we found that for the inner part of the clusters (r/r(200)less than or equal to1) the VDP is up to 10% smaller than at larger radii. C1 Astron Observ, Grp Invest Astron Teor & Expt, RA-5000 Cordoba, Argentina. Pontificia Univ Catolica Chile, Dept Astron & Astrofis, Santiago 22, Chile. NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA. Consejo Nacl Invest Cient & Tecn, RA-1033 Buenos Aires, DF, Argentina. RP Astron Observ, Grp Invest Astron Teor & Expt, Laprida 854, RA-5000 Cordoba, Argentina. RI Way, Michael/D-5254-2012; OI Way, Michael/0000-0003-3728-0475 NR 29 TC 13 Z9 13 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-6256 EI 1538-3881 J9 ASTRON J JI Astron. J. PD OCT PY 2002 VL 124 IS 4 BP 1934 EP 1942 DI 10.1086/342854 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 596BF UT WOS:000178143400006 ER PT J AU Maoz, D Markowitz, A Edelson, R Nandra, K AF Maoz, D Markowitz, A Edelson, R Nandra, K TI X-Ray versus optical variations in the Seyfert 1 nucleus NGC 3516: A puzzling disconnectedness SO ASTRONOMICAL JOURNAL LA English DT Article DE galaxies : active; galaxies : individual (NGC 3516); galaxies : Seyfert; X-rays ID SHORT-TIMESCALE VARIABILITY; ACTIVE GALACTIC NUCLEI; MULTIWAVELENGTH OBSERVATIONS; NGC 4151; GALAXY ARAKELIAN-564; CONTINUUM VARIABILITY; ASCA OBSERVATIONS; ACCRETION DISKS; TIME LAGS; EMISSION AB We present optical broadband (B and R) observations of the Seyfert 1 nucleus NGC 3516 obtained at Wise Observatory from 1997 March to 2002 March, contemporaneously with X-ray 2-10 keV measurements with RXTE. With these data we increase the temporal baseline of this data set to 5 years, more than triple the coverage we have previously presented for this object. Analysis of the new data does not confirm the 100 day lag of X-ray behind optical variations tentatively reported in our previous work. Indeed, excluding the first year's data, which drove the previous result, there is no significant correlation at any lag between the X-ray and optical bands. We also find no correlation at any lag between optical flux and various X-ray hardness ratios. We conclude that the close relation observed between the bands during the first year of our program was either a fluke or perhaps the result of the exceptionally bright state of NGC 3516 in 1997, to which it has yet to return. Reviewing the results of published joint X-ray and UV optical Seyfert monitoring programs, we speculate that there are at least two components or mechanisms contributing to the X-ray continuum emission up to 10 keV: a soft component that is correlated with UV optical variations on timescales greater than or similar to1 day and whose presence can be detected when the source is observed at low enough energies (similar to1 keV), is unabsorbed, or is in a sufficiently bright phase, and a hard component whose variations are uncorrelated with the UV optical. C1 Tel Aviv Univ, Sch Phys & Astron, IL-69978 Tel Aviv, Israel. Tel Aviv Univ, Wise Observ, IL-69978 Tel Aviv, Israel. Columbia Univ, Dept Astron, New York, NY 10027 USA. Univ Leicester, Xray Astron Grp, Leicester LE1 7RH, Leics, England. Eureka Sci, Oakland, CA 94602 USA. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. Univ Space Res Assoc, Columbia, MD 21044 USA. RP Tel Aviv Univ, Sch Phys & Astron, IL-69978 Tel Aviv, Israel. EM dani@wise.tau.ac.il NR 39 TC 39 Z9 39 U1 0 U2 2 PU IOP PUBLISHING LTD PI BRISTOL PA TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND SN 0004-6256 EI 1538-3881 J9 ASTRON J JI Astron. J. PD OCT PY 2002 VL 124 IS 4 BP 1988 EP 1994 DI 10.1086/342937 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 596BF UT WOS:000178143400011 ER PT J AU Stephens, AW Frogel, JA AF Stephens, AW Frogel, JA TI The structure and stellar content of the central region of M33 SO ASTRONOMICAL JOURNAL LA English DT Article DE galaxies : individual ( M33, NCG 598) ID RICH GLOBULAR-CLUSTERS; INFRARED ARRAY PHOTOMETRY; LARGE MAGELLANIC CLOUD; LOCAL GROUP GALAXIES; H-II REGIONS; STAR-CLUSTERS; SPIRAL GALAXIES; SURROUNDING FIELDS; GIANT BRANCHES; BAADES WINDOW AB Using Gemini QuickStart infrared observations of the central 22" of M33, we analyze the stellar populations in this controversial region. Based on the slope of the giant branch we estimate the mean metallicity to be -0.26+/-0.27, and from the luminosities of the most luminous stars, we estimate that there were two bursts of star formation, similar to2 and similar to0.5 Gyr ago. We show that the stellar luminosity function not has only a different bright end cutoff, but also a significantly different slope than that of the Galactic bulge, and we suggest that this difference is due to the young stellar component in M33. We combine our infrared Gemini data with optical Hubble Space Telescope Wide Field Planetary Camera 2 measurements revealing a color-magnitude diagram populated with young, intermediate-age, and old stellar populations. Using surface brightness profiles from 0".1 to 18', we perform simple decompositions and show that the data are best fitted by a three-component core plus bulge plus disk model. Finally, we find no evidence for radial variations of the stellar populations in the inner 3"-10" of M33, based on a spatial analysis of the color-magnitude diagrams and luminosity functions. C1 Pontificia Univ Catolica Chile, Dept astron & Astrofis, Santiago 22, Chile. Princeton Univ Observ, Princeton, NJ 08544 USA. NASA Headquarters, Washington, DC 20546 USA. Ohio State Univ, Dept Astron, Columbus, OH 43210 USA. RP Stephens, AW (reprint author), Pontificia Univ Catolica Chile, Dept astron & Astrofis, Casilla 306, Santiago 22, Chile. NR 54 TC 25 Z9 25 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-6256 J9 ASTRON J JI Astron. J. PD OCT PY 2002 VL 124 IS 4 BP 2023 EP 2038 DI 10.1086/342538 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 596BF UT WOS:000178143400015 ER PT J AU Andersson, BG Idzi, R Uomoto, A Wannier, PG Chen, B Jorgensen, AM AF Andersson, BG Idzi, R Uomoto, A Wannier, PG Chen, B Jorgensen, AM TI A spectroscopic and photometric survey of stars in the field of L1457: A new distance determination SO ASTRONOMICAL JOURNAL LA English DT Article DE ISM : individual (L1457) ID MOLECULAR CLOUD MBM-12; INTERSTELLAR-MEDIUM; EXTINCTION; VICINITY; PERSEUS; TAURUS AB We present a spectroscopic and photometric survey of a sample of field stars in the region of the molecular cloud L1457. High-quality coude feed spectra, together with five-band photometry in the Sloan Digital Sky Survey system and near-infrared archival data from the Two Micron All Sky Survey, are used to derive color excesses and distances for the stars. Based on these data, a new distance estimate of 360 +/- 30 pc is derived for the cloud, supporting recent results by K. L. Luhman. The data further indicate that the north-south velocity gradient seen in the millimeter-wave CO data is mirrored in a distance gradient, with the northern part of the cloud being closer to us. A second, less opaque, layer of extinction is detected at similar to80 pc. This distance is consistent with the earlier distance estimates to the cloud, based on Na I absorption. We identify this layer with the wall of the hot Local Bubble. Hence, the dense cloud is not, as previously thought, associated with the Local Bubble. C1 Johns Hopkins Univ, Ctr Astrophys Sci, Baltimore, MD 21218 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Los Alamos Natl Lab, Los Alamos, NM 87545 USA. RP Andersson, BG (reprint author), Johns Hopkins Univ, Ctr Astrophys Sci, 3400 N Charles St, Baltimore, MD 21218 USA. NR 29 TC 23 Z9 23 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-6256 J9 ASTRON J JI Astron. J. PD OCT PY 2002 VL 124 IS 4 BP 2164 EP 2177 DI 10.1086/342541 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 596BF UT WOS:000178143400027 ER PT J AU Greene, TP Lada, CJ AF Greene, TP Lada, CJ TI Spectroscopic detection of a stellar-like photosphere in an accreting protostar SO ASTRONOMICAL JOURNAL LA English DT Article DE infrared radiation; stars : atmospheres; stars : formation; stars : rotation; techniques : spectroscopic ID RHO-OPHIUCHI CLOUD; MAIN-SEQUENCE STARS; NEAR-INFRARED SPECTRA; T-TAURI STARS; MAGNETOCENTRIFUGALLY DRIVEN FLOWS; YOUNG STARS; LOW-MASS; OBJECTS; DISKS; ROTATION AB We present high-resolution (R similar or equal to 18,000), high signal-to-noise 2 mum spectra of two luminous, X-ray flaring Class I protostars in the rho Ophiuchi cloud acquired with the NIRSPEC spectrograph of the Keck II telescope. We present the first spectrum of a highly veiled, strongly accreting protostar, which shows photospheric absorption features and demonstrates the stellar nature of its central core. We find the spectrum of the luminous (L-bol = 10 L.) protostellar source, YLW 15, to be stellar-like with numerous atomic and molecular absorption features, indicative of a K5 IV/V spectral type and a continuum veiling r(k) = 3.0. Its derived stellar luminosity (3 L.) and stellar radius (3.1 R.) are consistent with those of a 0.5 M. pre-main-sequence star. However, 70% of its bolometric luminosity is due to mass accretion, whose rate we estimate to be 1.6 x 10(6) M. yr(-1), onto the protostellar core. We determine that excess infrared emission produced by the circumstellar accretion disk, the inner infalling envelope, and accretion shocks at the surface of the stellar core of YLW 15 all contribute significantly to its near-IR continuum veiling. Its projected rotation velocity v sin i = 50 km s(-1) is comparable to those of at-spectrum protostars, but considerably higher than those of classical T Tauri stars in the rho Oph cloud. The protostar may be magnetically coupled to its circumstellar disk at a radius of 2 R-*. It is also plausible that this protostar can shed over half its angular momentum and evolve into a more slowly rotating classical T Tauri star by remaining coupled to its circumstellar disk (at increasing radius) as its accretion rate drops by an order of magnitude during the rapid transition between the Class I and Class II phases of evolution. The spectrum of WL6 does not show any photospheric absorption features, and we estimate that its continuum veiling is r(k)greater than or equal to4.6. Its low bolometric luminosity (2 L.) and high veiling dictate that its central protostar is very low mass, M similar to 0.1 M.. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Greene, TP (reprint author), NASA, Ames Res Ctr, Mail Stop 245-6, Moffett Field, CA 94035 USA. NR 43 TC 38 Z9 38 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-6256 J9 ASTRON J JI Astron. J. PD OCT PY 2002 VL 124 IS 4 BP 2185 EP 2193 DI 10.1086/342861 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 596BF UT WOS:000178143400029 ER PT J AU Chauvin, G Fusco, T Lagrange, AM Mouillet, D Beuzit, JL Thomson, M Augereau, JC Marchis, F Dumas, C Lowrance, P AF Chauvin, G Fusco, T Lagrange, AM Mouillet, D Beuzit, JL Thomson, M Augereau, JC Marchis, F Dumas, C Lowrance, P TI No disk needed around HD 199143 B SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE stars : imaging; binaries : general; stars : low-mass, brown dwarfs; stars : pre-main sequence ID MOLECULAR CLOUD; STAR-FORMATION; ASSOCIATION; DISCOVERY AB We present new, high angular resolution images of HD 199143 in the Capricornus association, obtained with the adaptive optics system ADONIS SHARPII at the ESO 3.6 m Telescope of La Silla Observatory. HD 199143 and its neighbour star HD 358623 (separation similar to5' away) have previously been imaged with adaptive optics. For each star, a companion has been detected in the J and K bands at respective separations of 1.1" and 2.2" (Jayawardhana & Brandeker 2001). Our new photometry of HD 199143 B suggests that it is a M2 star and that the presence of circumstellar dust proposed by van den Ancker et al. (2000) is no longer necessary. We show that the 12 mum flux detected by IRAS previously interpreted as an IR excess, can be explained by the presence of the late-type companion. C1 Observ Grenoble, Astrophys Lab, F-38041 Grenoble 9, France. Off Natl Etud & Rech Aerosp, Dept Opt Theor & Appl, F-92322 Chatillon, France. Observ Midi Pyrenees, Astrophys Lab, F-65008 Tarbes, France. Univ London Imperial Coll Sci Technol & Med, London SW7 2AZ, England. CEA Saclay, DSM DAPNIA, Serv Astrophys, F-91191 Gif Sur Yvette, France. Univ Calif Berkeley, Ctr Adapt Opt, Berkeley, CA 94720 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Chauvin, G (reprint author), Observ Grenoble, Astrophys Lab, 414 Rue Piscine,BP 53, F-38041 Grenoble 9, France. EM gchauvin@obs.ujf-grenoble.fr RI Marchis, Franck/H-3971-2012 NR 17 TC 5 Z9 5 U1 0 U2 0 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD OCT PY 2002 VL 394 IS 1 BP 219 EP 223 DI 10.1051/0004-6361:20021114 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 603TB UT WOS:000178575000028 ER PT J AU Nurnberger, DEA Bronfman, L Yorke, HW Zinnecker, H AF Nurnberger, DEA Bronfman, L Yorke, HW Zinnecker, H TI The molecular environment of NGC3603 - I. Spatial distribution and kinematic structure SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE stars : formation; ISM : clouds; HII regions; ISM : individual objects : NGC 3603; ISM : kinematics and dynamics; ISM : structure ID REGION NGC 3603; SOUTHERN HII-REGIONS; ORION NEBULA CLUSTER; WOLF-RAYET STARS; HIGH-RESOLUTION; STELLAR CONTENT; INFALL MOTIONS; MASSIVE STARS; H2O MASERS; MILKY-WAY AB We present CS (2-1) and CS (3-2) observations of the molecular gas associated with the Galactic starburst template NGC 3603, over an area of 5.'8 x 16.'7, with the OB cluster at the center. Total velocity integrated maps and channel maps give insight into the spatial distribution and the kinematic structure of the dense gas in the giant molecular cloud from which the starburst cluster originated. We identify 13 molecular clumps with radii less than 0.8 pc and derive upper limits for their virial masses as well as lower limits for their H-2 column densities: (M-vir) less than or similar to (1.0 +/- 0.6) x 10(3) M-. and N (H-2) greater than or similar to (0.4 +/- 0.2) x 10(23) cm(-2). One of the clumps, MM11, clearly stands out with a mass and column density 4 times higher than average. The CS (3-2) / CS (2-1) map shows higher intensity ratios to the south of the OB cluster than to the north (0.80 +/- 0.08 versus 0.32 +/- 0.11), which indicates a substantial difference in the physical conditions (either opacities or excitation temperatures) of the molecular gas. From the average of the line peak velocities, 14.2 +/- 1.6 km s(-1), we deduce a kinematic distance of 7.7 +/- 0.2 kpc for NGC 3603. We estimate the star formation efficiency (greater than or similar to 30%) of the central part of the NGC 3603 H II region. If we assume the age of the OB cluster to be less than 3 Myr and the star formation rate to be larger than 1.3 x 10(-3) M-. yr(-1), the derived timescale for gas removal ( 6 Myr) can explain why the starburst cluster itself is nearly void of interstellar material. The remnant clump MM 1 appears to constitute the head of a prominent pillar which still becomes dispersed by ionizing radiation and stellar winds originating from the massive stars of the cluster. Because some of the molecular clumps are associated with near and mid infrared sources as well as OH, H2O and CH3OH maser sources we conclude that star formation is still going on within NGC 3603. C1 Univ Wurzburg, Inst Theoret Phys & Astrophys, D-97074 Wurzburg, Germany. Inst Radio Astron Millimetr, F-38406 St Martin Dheres, France. Univ Chile, Dept Astron, Santiago, Chile. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Astrophys Inst Potsdam, D-14482 Potsdam, Germany. RP Nurnberger, DEA (reprint author), Univ Wurzburg, Inst Theoret Phys & Astrophys, D-97074 Wurzburg, Germany. RI Bronfman, Leonardo/H-9544-2013 OI Bronfman, Leonardo/0000-0002-9574-8454 NR 72 TC 30 Z9 30 U1 0 U2 0 PU E D P SCIENCES PI LES ULIS CEDEXA PA 7, AVE DU HOGGAR, PARC D ACTIVITES COURTABOEUF, BP 112, F-91944 LES ULIS CEDEXA, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD OCT PY 2002 VL 394 IS 1 BP 253 EP 269 DI 10.1051/0004-6361:20021022 PG 17 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 603TB UT WOS:000178575000032 ER PT J AU Kawamura, J Hunter, TR Tong, CYE Blundell, R Papa, DC Patt, F Peters, W Wilson, TL Henkel, C Gol'tsman, G Gershenzon, E AF Kawamura, J Hunter, TR Tong, CYE Blundell, R Papa, DC Patt, F Peters, W Wilson, TL Henkel, C Gol'tsman, G Gershenzon, E TI Ground-based terahertz CO spectroscopy towards orion SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE ISM : molecules; ISM : individual objects : orion KL; submillimeter ID BOLOMETER MIXER RECEIVER; KLEINMANN-LOW NEBULA; HETERODYNE SPECTROSCOPY; MOLECULAR CLOUD; ATMOSPHERIC TRANSMISSION; SUBMILLIMETER; EMISSION; OUTFLOW; LINE; GAS AB Using a superconductive hot-electron bolometer heterodyne receiver on the 10-m Heinrich Hertz Telescope on Mount Graham, Arizona, we have obtained velocity-resolved 1.037 THz CO (J = 9 --> 8) spectra toward several positions along the Orion Molecular Cloud (OMC-1) ridge. We confirm the general results of prior observations of high-J CO lines that show that the high temperature, T-kin greater than or equal to 130 K, high density molecular gas, n greater than or equal to 10(6) cm(-3), is quite extended, found along asimilar to4' region centered on BN/KL. However, our observations have significantly improved angular resolution, and with a beam size of theta(FWHP) approximate to 9" we are able to spatially and kinematically discriminate the emission originating in the extended quiescent ridge from the very strong and broadened emission originating in the compact molecular outflow. The ridge emission very close to the BN/KL region appears to originate from two distinct clouds along the line of sight with v(LSR) approximate to+ 6(1) km s(-1) and approximate to+10(1) km s(-1). The former component dominates the emission to the south of BN/KL and the latter to the north, with a turnover point coincident with or near BN/KL. Our evidence precludes a simple rotation of the inner ridge and lends support to a model in which there are multiple molecular clouds along the line of sight towards the Orion ridge. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Submillimeter Inst Radioastron, Tucson, AZ 85721 USA. Moscow State Pedag Univ, Moscow 119435, Russia. Max Planck Inst Radioastron, D-53010 Bonn, Germany. RP Kawamura, J (reprint author), CALTECH, Jet Prop Lab, MS 168-314, Pasadena, CA 91109 USA. OI Tong, Edward/0000-0002-7736-4203; Hunter, Todd/0000-0001-6492-0090 NR 36 TC 24 Z9 25 U1 0 U2 0 PU E D P SCIENCES PI LES ULIS CEDEXA PA 7, AVE DU HOGGAR, PARC D ACTIVITES COURTABOEUF, BP 112, F-91944 LES ULIS CEDEXA, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD OCT PY 2002 VL 394 IS 1 BP 271 EP 274 DI 10.1051/0004-6361:20021090 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 603TB UT WOS:000178575000033 ER PT J AU Mora, A Natta, A Eiroa, C Grady, CA de Winter, D Davies, JK Ferlet, R Harris, AW Montesinos, B Oudmaijer, RD Palacios, J Quirrenbach, A Rauer, H Alberdi, A Cameron, A Deeg, HJ Garzon, F Horne, K Merin, B Penny, A Schneider, J Solano, E Tsapras, Y Wesselius, PR AF Mora, A Natta, A Eiroa, C Grady, CA de Winter, D Davies, JK Ferlet, R Harris, AW Montesinos, B Oudmaijer, RD Palacios, J Quirrenbach, A Rauer, H Alberdi, A Cameron, A Deeg, HJ Garzon, F Horne, K Merin, B Penny, A Schneider, J Solano, E Tsapras, Y Wesselius, PR TI A dynamical study of the circumstellar gas in UX Orionis SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE stars : formation; stars : pre-main sequence; stars : circumstellar matter; accretion, accretion disks; line : profiles; stars : individual : UX Ori ID MAIN-SEQUENCE STARS; SU-AURIGAE; VEGA-TYPE; MAGNETOSPHERIC ACCRETION; STROMGREN PHOTOMETRY; BETA-PICTORIS; HERBIG STARS; CLASSIFICATION; EXPORT; CONFRONTATION AB We present the results of a high spectral resolution (lambda/Deltalambda = 49 000) study of the circumstellar (CS) gas around the intermediate mass, pre-main sequence star UX Ori. The results are based on a set of 10 echelle spectra covering the spectral range 3800-5900 Angstrom, monitoring the star on time scales of months, days and hours. A large number of transient blueshifted and redshifted absorption features are detected in the Balmer and in many metallic lines. A multigaussian fit is applied to determine for each transient absorption the velocity, v, dispersion velocity, Deltav, and the parameter R, which provides a measure of the absorption strength of the CS gas. The time evolution of those parameters is presented and discussed. A comparison of intensity ratios among the transient absorptions suggests a solar-like composition of the CS gas. This confirms previous results and excludes a very metal-rich environment as the cause of the transient features in UX Ori. The features can be grouped by their similar velocities into 24 groups, of which 17 are redshifted and 7 blueshifted. An analysis of the velocity of the groups allows us to identify them as signatures of the dynamical evolution of 7 clumps of gas, of which 4 represent accretion events and 3 outflow events. Most of the events decelerate at a rate of tenths of ms(-2), while 2 events accelerate at approximately the same rate; one event is seen experiencing both an acceleration and a deceleration phase and lasts for a period of few days. This time scale seems to be the typical duration of outflowing and infalling events in UX Ori. The dispersion velocity and the relative aborption strength of the features do not show drastic changes during the lifetime of the events, which suggests they are gaseous blobs preserving their geometrical and physical identity. These data are a very useful tool for constraining and validating theoretical models of the chemical and physical conditions of CS gas around young stars; in particular, we suggest that the simultaneous presence of infalling and outflowing gas should be investigated in the context of detailed magnetospheric accretion models, similar to those proposed for the lower mass T Tauri stars. C1 Univ Autonoma Madrid, Dept Fis Teor C11, E-28049 Madrid, Spain. Osserv Astrofis Arcetri, I-50125 Florence, Italy. NASA, NOAO, STIS, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. TNO, TPD Space Instrumentat, NL-2600 AD Delft, Netherlands. Royal Observ, Astron Technol Ctr, Edinburgh EH9 3HJ, Midlothian, Scotland. Inst Astrophys Paris, CNRS, F-75014 Paris, France. DLR, Dept Planetary Explorat, D-12489 Berlin, Germany. Inst Astrofis Andalucia, E-18080 Granada, Spain. VILSPA, LAEFF, Madrid 28080, Spain. Univ Leeds, Dept Phys & Astron, Leeds LS2 9JT, W Yorkshire, England. Univ Calif San Diego, Ctr Astrophys & Space Sci, Dept Phys, La Jolla, CA 92093 USA. Univ St Andrews, St Andrews KY16 9SS, Fife, Scotland. Inst Astrofis Canarias, Tenerife 38200, Spain. Rutherford Appleton Lab, Didcot OX11 0QX, Oxon, England. Observ Paris, F-92195 Meudon, France. SRON, NL-9700 AV Groningen, Netherlands. RP Mora, A (reprint author), Univ Autonoma Madrid, Dept Fis Teor C11, E-28049 Madrid, Spain. RI Solano, Enrique/C-2895-2017; Montesinos, Benjamin/C-3493-2017; OI Montesinos, Benjamin/0000-0002-7982-2095; Cameron, Andrew/0000-0002-8863-7828; Deeg, Hans-Jorg/0000-0003-0047-4241; Merin, Bruno/0000-0002-8555-3012 NR 35 TC 22 Z9 22 U1 0 U2 1 PU E D P SCIENCES PI LES ULIS CEDEXA PA 7, AVE DU HOGGAR, PARC D ACTIVITES COURTABOEUF, BP 112, F-91944 LES ULIS CEDEXA, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD OCT PY 2002 VL 393 IS 1 BP 259 EP 271 DI 10.1051/0004-6361:20021030 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 596YC UT WOS:000178193200026 ER PT J AU Pottasch, SR Beintema, DA Salas, JB Koornneef, J Feibelman, WA AF Pottasch, SR Beintema, DA Salas, JB Koornneef, J Feibelman, WA TI Abundances of planetary nebula NGC 5315 SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE ISM : abundances; planetary nebulae : individual : NGC 5315; infrared : ISM; ISM : lines and bands ID SPECTRUM; STARS; SPECTROPHOTOMETRY; SPECTROSCOPY; DISTANCES; FLUXES; SAMPLE; LINES AB The ISO and IUE spectra of the elliptical nebula NGC 5315 is presented. These spectra are combined with the spectra in the visual wavelength region to obtain a complete, extinction corrected, spectrum. The chemical composition of the nebulae is then calculated and compared to previous determinations. The HST NICMOS observations of the nebula in 3 emission lines are also presented. These observations are used to determine the helium abundance as a function of position in the nebula. A discussion is given of possible evolutionary effects. C1 Kapteyn Astron Inst, NL-9700 AV Groningen, Netherlands. SRON, Natl Inst Space Res, NL-9700 AV Groningen, Netherlands. Infostrait Bv, NL-7301 BD Apeldoorn, Netherlands. NASA, Astron & Solar Phys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Pottasch, SR (reprint author), Kapteyn Astron Inst, POB 800, NL-9700 AV Groningen, Netherlands. NR 31 TC 26 Z9 26 U1 0 U2 0 PU E D P SCIENCES PI LES ULIS CEDEXA PA 7, AVE DU HOGGAR, PARC D ACTIVITES COURTABOEUF, BP 112, F-91944 LES ULIS CEDEXA, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD OCT PY 2002 VL 393 IS 1 BP 285 EP 294 DI 10.1051/0004-6361:20020986 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 596YC UT WOS:000178193200028 ER PT J AU Ceron, JMC Castro-Tirado, AJ Gorosabel, J Hjorth, J Fynbo, JU Jensen, BL Pedersen, H Andersen, MI Lopez-Corredoira, M Suarez, O Grosdidier, Y Casares, J Perez-Ramirez, DP Milvang-Jensen, B Mallen-Ornelas, G Fruchter, A Greiner, J Pian, E Vreeswijk, PM Barthelmy, SD Cline, T Frontera, F Kaper, L Klose, S Kouveliotou, C Hartmann, DH Hurley, K Masetti, N Mazets, E Palazzi, E Park, HS Rol, E Salamanca, I Tanvir, N Trombka, JI Wijers, RAMJ Williams, GG van den Heuvel, E AF Ceron, JMC Castro-Tirado, AJ Gorosabel, J Hjorth, J Fynbo, JU Jensen, BL Pedersen, H Andersen, MI Lopez-Corredoira, M Suarez, O Grosdidier, Y Casares, J Perez-Ramirez, DP Milvang-Jensen, B Mallen-Ornelas, G Fruchter, A Greiner, J Pian, E Vreeswijk, PM Barthelmy, SD Cline, T Frontera, F Kaper, L Klose, S Kouveliotou, C Hartmann, DH Hurley, K Masetti, N Mazets, E Palazzi, E Park, HS Rol, E Salamanca, I Tanvir, N Trombka, JI Wijers, RAMJ Williams, GG van den Heuvel, E TI The bright optical afterglow of the long GRB 001007 SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE gamma rays : bursts; techniques : photometric; cosmology : observations ID GAMMA-RAY BURSTS; LIGHT CURVES AB We present optical follow up observations of the long GRB 001007 between 6.14 hours and similar to468 days after the event. An unusually bright optical afterglow (OA) was seen to decline following a steep power law decay with index alpha = -2.03 +/- 0.11, possibly indicating a break in the light curve at t - t(0) < 3.5 days, as found in other bursts. Upper limits imposed by the LOTIS alerting system 6.14 hours after the gamma ray event provide tentative (1.2σ) evidence for a break in the optical light curve. The spectral index β of the OA yields -1.24 +/- 0.57. These values may be explained both by several fireball jet models and by the cannonball model. Fireball spherical expansion models are not favoured. Late epoch deep imaging revealed the presence of a complex host galaxy system, composed of at least two objects located 1.2" (1.7σ) and 1.9" (2.7σ) from the afterglow position. C1 Real Inst, Cadiz 11110, Spain. Observ Armada, Secc Astron, Cadiz 11110, Spain. CSIC, Inst Astrofis Andalucia, E-18080 Granada, Spain. Danish Space Res Inst, DK-2100 Copenhagen O, Denmark. INTA, Lab Astrofis Espacial & Fis Fundamental, Madrid 28080, Spain. Univ Copenhagen, Astron Observ, DK-2100 Copenhagen O, Denmark. European So Observ, D-85748 Garching, Germany. Univ Oulu, Div Astron, Oulu 90014, Finland. Inst Astrofis Canarias, Tenerife 38200, Spain. Univ de la Coruna, Dept Ciencias Nevegac & Tierra, La Coruna 15011, Spain. Michigan Technol Univ, Dept Phys, Houghton, MI 49931 USA. Univ Nottingham, Sch Phys & Astron, Nottingham NG7 2RD, England. Univ Toronto, Dept Astron, Toronto, ON M5S 3H8, Canada. Space Telescope Sci Inst, Baltimore, MD 21218 USA. Inst Astrophys, D-14482 Potsdam, Germany. Osserv Astron Trieste, I-34131 Trieste, Italy. Univ Amsterdam, NL-1098 SJ Amsterdam, Netherlands. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. CNR, Ist Astrofis Spaziale & Fis Cosm, Sez Bologna, I-40129 Bologna, Italy. Thuringer Landessternwarte Tautenburg, D-07778 Tautenburg, Germany. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. Clemson Univ, Clemson, SC 29634 USA. Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. AF Ioffe Phys Tech Inst, St Petersburg 194021, Russia. Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. Univ Hertfordshire, Dept Phys Sci, Hatfield AL10 9AB, Herts, England. SUNY Stony Brook, Dept Phys & Astron, Stony Brook, NY 11794 USA. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. RP Ceron, JMC (reprint author), Real Inst, Cadiz 11110, Spain. RI Barthelmy, Scott/D-2943-2012; Hjorth, Jens/M-5787-2014; Jensen, Brian Lindgren/E-1275-2015; Palazzi, Eliana/N-4746-2015; OI Hjorth, Jens/0000-0002-4571-2306; Jensen, Brian Lindgren/0000-0002-0906-9771; Wijers, Ralph/0000-0002-3101-1808; Palazzi, Eliana/0000-0002-8691-7666; Castro-Tirado, A. J./0000-0003-2999-3563; Masetti, Nicola/0000-0001-9487-7740; Pian, Elena/0000-0001-8646-4858 NR 27 TC 6 Z9 6 U1 1 U2 3 PU E D P SCIENCES PI LES ULIS CEDEXA PA 7, AVE DU HOGGAR, PARC D ACTIVITES COURTABOEUF, BP 112, F-91944 LES ULIS CEDEXA, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD OCT PY 2002 VL 393 IS 2 BP 445 EP 451 DI 10.1051/0004-6361:20021010 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 597YB UT WOS:000178247400011 ER PT J AU Castro-Tirado, AJ Ceron, JMC Gorosabel, J Pata, P Soldan, J Hudec, R Jelinek, M Topinka, M Bernas, M Sanguino, TJM Postigo, AD Berna, JA Henden, A Vrba, F Canzian, B Harris, H Delfosse, X de Pontieu, B Polcar, J Sanchez-Fernandez, C de la Morena, BA Mas-Hesse, JM Riera, JT Barthelmy, S AF Castro-Tirado, AJ Ceron, JMC Gorosabel, J Pata, P Soldan, J Hudec, R Jelinek, M Topinka, M Bernas, M Sanguino, TJM Postigo, AD Berna, JA Henden, A Vrba, F Canzian, B Harris, H Delfosse, X de Pontieu, B Polcar, J Sanchez-Fernandez, C de la Morena, BA Mas-Hesse, JM Riera, JT Barthelmy, S TI Detection of an optical transient following the 13 March 2000 short/hard gamma-ray burst SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE gamma rays : bursts; optical transients; techniques : photometric; cosmology : observations ID SHORT-DURATION; AFTERGLOW; EMISSION AB We imaged the error box of a gamma-ray burst of the short (0.5 s), hard type (GRB 000313), with the BOOTES-1 experiment in southern Spain, starting 4 min after the gamma-ray event, in the I-band. A bright optical transient (OT 000313) with I = 9.4 +/- 0.1 was found in the BOOTES-1 image, close to the error box (3sigma) provided by BATSE. Late time VRI K'-band deep observations failed to reveal an underlying host galaxy. If the OT 000313 is related to the short, hard GRB 000313, this would be the first optical counterpart ever found for this kind of events (all counterparts to date have been found for bursts of the long, soft type). The fact that only prompt optical emission has been detected (but no afterglow emission at all, as supported by theoretical models) might explain why no optical counterparts have ever been found for short, hard GRBs. This fact suggests that most short bursts might occur in a low-density medium and favours the models that relate them to binary mergers in very low-density environments. C1 CSIC, Inst Astrofis Andalucia, E-18080 Granada, Spain. INTA, LAEFF, Madrid 28080, Spain. Real Inst, Cadiz 11110, Spain. Observ Armada, Secc Astron, Cadiz 11110, Spain. Danish Space Res Inst, DK-2100 Copenhagen O, Denmark. Czech Tech Univ, Fac Elect Engn, Dept Radioelect, Prague 16627, Czech Republic. Acad Sci Czech Republic, Inst Astron, CS-25165 Ondrejov, Czech Republic. INTA, CEDEA, Mazagon 21130, Huelva, Spain. Univ Complutense, Dept Astrofis, E-28040 Madrid, Spain. Univ Alicante, Dept Fis Ingn Sistemas & Teoria Senal, E-03080 Alicante, Spain. Univ Space Res Assoc, Flagstaff Stn, Flagstaff, AZ USA. USN Observ, Flagstaff Stn, Flagstaff, AZ USA. Observ Grenoble, Astrophys Lab, Grenoble, France. Lockheed Martin Solar & Astrophys Lab, Palo Alto, CA 94304 USA. Masaryk Univ, Dept Theoret Phys & Astrophys, Brno, Czech Republic. INTA, DCE, Madrid 28850, Spain. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP CSIC, Inst Astrofis Andalucia, POB 03004, E-18080 Granada, Spain. EM ajct@iaa.es RI Barthelmy, Scott/D-2943-2012; Pata, Petr/D-5817-2013; Hudec, Rene/G-9018-2014; Mas-Hesse, J. Miguel /K-6805-2014; Jelinek, Martin/E-5290-2016; OI Pata, Petr/0000-0002-6561-9088; Mas-Hesse, J. Miguel /0000-0002-8823-9723; Jelinek, Martin/0000-0003-3922-7416; de Ugarte Postigo, Antonio/0000-0001-7717-5085 NR 31 TC 19 Z9 19 U1 0 U2 1 PU EDP SCIENCES S A PI LES ULIS CEDEX A PA 17, AVE DU HOGGAR, PA COURTABOEUF, BP 112, F-91944 LES ULIS CEDEX A, FRANCE SN 1432-0746 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD OCT PY 2002 VL 393 IS 3 BP L55 EP L59 DI 10.1051/0004-6361:20021172 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 599AY UT WOS:000178313000003 ER PT J AU Hony, S Bouwman, J Keller, LP Waters, LBFM AF Hony, S Bouwman, J Keller, LP Waters, LBFM TI The detection of iron sulfides in Planetary Nebulae SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE circumstellar matter; Planetary Nebulae : individual : PN M2-43, PNK3-17; stars : mass-loss ID CARBON-RICH STARS; DUST; MAGNESIUM AB We present and discuss the detection, through mid IR spectroscopy, of iron sulfides in the carbon rich ejecta of evolved stars. We find the spectroscopic signature of iron sulfides at 23 mum. We also find weak features at similar to34, 38 and 44 mum. The positions of these features correspond well with the resonances of the iron sulfide troilite. However, the relative strength of the 23 mum versus the other bands does not match the laboratory measurements, which suggests the presence of other iron sulfides besides troilite. The same broad feature around 23 mum has been found in young stellar objects. This detection may imply a carbon star origin for part of the iron sulfides found in meteorites and interplanetary dust particles. C1 Univ Amsterdam, Astron Inst Anton Pannekoek, NL-1098 SJ Amsterdam, Netherlands. CENS, Serv Astrophys, DAPNIA, DSM,CEA, F-91191 Gif Sur Yvette, France. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. Katholieke Univ Leuven, Inst Sterrenkunde, B-3001 Heverlee, Belgium. RP Hony, S (reprint author), Univ Amsterdam, Astron Inst Anton Pannekoek, Kruislaan 403, NL-1098 SJ Amsterdam, Netherlands. NR 19 TC 27 Z9 27 U1 0 U2 3 PU E D P SCIENCES PI LES ULIS CEDEXA PA 7, AVE DU HOGGAR, PARC D ACTIVITES COURTABOEUF, BP 112, F-91944 LES ULIS CEDEXA, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD OCT PY 2002 VL 393 IS 3 BP L103 EP L106 DI 10.1051/0004-6361:20021260 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 599AY UT WOS:000178313000014 ER PT J AU Swordy, SP Fortson, LF Hinton, J Horandel, J Knapp, J Pryke, CL Shibata, T Wakely, SP Cao, Z Cherry, ML Coutu, S Cronin, J Engel, R Fowler, JW Kampert, KH Kettler, J Kieda, DB Matthews, J Minnick, SA Moiseev, A Muller, D Roth, M Sill, A Spiczak, G AF Swordy, SP Fortson, LF Hinton, J Horandel, J Knapp, J Pryke, CL Shibata, T Wakely, SP Cao, Z Cherry, ML Coutu, S Cronin, J Engel, R Fowler, JW Kampert, KH Kettler, J Kieda, DB Matthews, J Minnick, SA Moiseev, A Muller, D Roth, M Sill, A Spiczak, G TI The composition of cosmic rays at the knee SO ASTROPARTICLE PHYSICS LA English DT Article DE cosmic rays; knee; energy spectrum; composition; Cherenkov ID ELECTRON-PHOTON SHOWERS; TOTAL CROSS-SECTION; = 1.8 TEV; ENERGY-SPECTRUM; AIR SHOWERS; SOUTH-POLE; COLLISIONS; PROTON; PRIMARIES; MAXIMUM AB The observation of a small change in spectral slope, or 'knee' in the fluxes of cosmic rays near energies 10(15) eV has caused much speculation since its discovery over 40 years ago. The origin of this feature remains unknown. A small workshop to review some modern experimental measurements of this region was held at the Adler Planetarium in Chicago, USA in June 2000. This paper summarizes the results presented at this workshop and the discussion of their interpretation in the context of hadronic models of atmospheric air showers. (C) 2002 Elsevier Science B.V. All rights reserved. C1 Univ Chicago, Enrico Fermi Inst, Chicago, IL 60637 USA. Adler Planetarium & Astron Museum, Dept Astron, Chicago, IL 60605 USA. Univ Karlsruhe, Inst Expt Kernphys, D-76021 Karlsruhe, Germany. Univ Leeds, Dept Phys & Astron, Leeds LS2 9JT, W Yorkshire, England. Aoyama Gakuin Univ, Dept Phys, Tokyo 1578572, Japan. Univ Utah, Dept Phys, High Energy Astrophys Lab, Salt Lake City, UT 84112 USA. Louisiana State Univ, Dept Phys & Astron, Baton Rouge, LA 70803 USA. Penn State Univ, Dept Phys, University Pk, PA 16802 USA. Univ Delaware, Bartol Res Inst, Newark, DE 19716 USA. Princeton Univ, Dept Phys, Princeton, NJ 08544 USA. Max Planck Inst Kernphys, D-69117 Heidelberg, Germany. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Texas Tech Univ, Dept Phys, Lubbock, TX 79409 USA. RP Univ Chicago, Enrico Fermi Inst, 5640 Ellis Ave, Chicago, IL 60637 USA. OI Knapp, Johannes/0000-0003-1519-1383; Horandel, Jorg/0000-0001-6604-547X; Kampert, Karl-Heinz/0000-0002-2805-0195 NR 82 TC 51 Z9 51 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0927-6505 EI 1873-2852 J9 ASTROPART PHYS JI Astropart Phys. PD OCT PY 2002 VL 18 IS 2 BP 129 EP 150 AR PII S0927-6505(02)00108-1 DI 10.1016/S0927-6505(02)00108-1 PG 22 WC Astronomy & Astrophysics; Physics, Particles & Fields SC Astronomy & Astrophysics; Physics GA 605GH UT WOS:000178668900001 ER PT J AU Henriksen, MJ Tittley, ER AF Henriksen, MJ Tittley, ER TI Chandra observations of the A3266 galaxy cluster merger SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : clusters : individual ( Abell 3266); intergalactic medium; X-rays : galaxies : clusters ID METALLICITY GRADIENTS; ABELL-3266; ABUNDANCE; DYNAMICS; PERSEUS; REGIONS; ASCA; COMA AB Analysis of a 30,000 s X-ray observation of the A3266 galaxy cluster with the ACIS on board the Chandra X-Ray Observatory has produced several new insights into the cluster merger. The intracluster medium has a nonmonotonically decreasing radial abundance pro le. We argue that the most plausible origin for the abundance enhancement is unmixed, high-abundance subcluster gas from the merger. The enrichment consists of two stages: off-center deposition of a higher abundance material during a subcluster merger followed by a strong, localized intracluster wind that acts to drive out the light elements, producing the observed abundance enhancement. The wind is needed to account for both an increase in the heavy-element abundance and the lack of an enhancement in the gas density. Dynamical evidence for the wind includes (1) a large-scale, low surface brightness feature perpendicular to the merger axis that appears to be an asymmetric pattern of gas flow to the northwest, away from the center of the main cluster; (2) compressed gas in the opposite direction (toward the cluster center); and (3) the fact that the hottest regions visible in the temperature map coincide with the proposed merger geometry and the resultant gas flow. The Chandra data for the central region of the main cluster show a slightly cooler, filamentary region that is centered on the central cD galaxy and is aligned with the merger axis directly linking the dynamical state of the cD to the merger. Overall, the high spectral/spatial resolution Chandra observations support our earlier hypothesis that we are viewing a minor merger in the plane of the sky. C1 Univ Maryland Baltimore Cty, Dept Phys, Joint Ctr Astrophys, Baltimore, MD 21250 USA. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Henriksen, MJ (reprint author), Univ Maryland Baltimore Cty, Dept Phys, Joint Ctr Astrophys, 1000 Hilltop Circle, Baltimore, MD 21250 USA. NR 23 TC 13 Z9 13 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD OCT 1 PY 2002 VL 577 IS 2 BP 701 EP 709 DI 10.1086/342115 PN 1 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 598WT UT WOS:000178300000013 ER PT J AU Tuthill, PG Monnier, JD Danchi, WC Hale, DDS Townes, CH AF Tuthill, PG Monnier, JD Danchi, WC Hale, DDS Townes, CH TI Imaging the disk around the luminous young star LkH alpha 101 with infrared interferometry SO ASTROPHYSICAL JOURNAL LA English DT Article DE circumstellar matter; infrared : stars; stars : individual (LkH alpha 101); stars : mass loss; techniques : interferometric ID HERBIG-AE/BE STARS; INTERMEDIATE-MASS STARS; T-TAURI STARS; ECCENTRIC GRAVITATIONAL INSTABILITIES; CIRCUMSTELLAR DISKS; STELLAR OBJECTS; PROTOSTELLAR DISKS; HIGH-RESOLUTION; ORION NEBULA; AB AURIGAE AB The Herbig Ae/Be star LkHalpha 101 has been imaged at high angular resolution at a number of wavelengths in the near-infrared (from 1 to similar to3 mum), using the Keck I Telescope, and also observed in the mid-infrared ( 11.15 mum), using the UC Berkeley Infrared Spatial Interferometer (ISI). The resolved circular disk with a central hole or cavity reported by Tuthill, Monnier, & Danchi is confirmed. This is consistent with an almost face-on view (inclination of less than or similar to35degrees) onto a luminous pre-main-sequence or early main-sequence object surrounded by a massive circumstellar disk. With a multiple-epoch study spanning almost 4 years, relative motion of the binary companion has been detected, together with evidence of changes in the brightness distribution of the central disk/star. The resolution of the LkHalpha 101 disk by ISI mid-infrared interferometry constitutes the first such measurement of a young stellar object in this wavelength region. The angular size was found to increase only slowly from 1.6 to 11.15 mum, inconsistent with standard power-law temperature proles usually encountered in the literature, supporting instead models with a hot inner cavity and relatively rapid transition to a cool or tenuous outer disk. The radius of the dust-free inner cavity is consistent with a model of sublimation of dust in equilibrium with the stellar radiation field. Measurements from interferometry have been combined with published photometry, enabling an investigation of the energetics and fundamental properties of this prototypical system. C1 Univ Sydney, Sch Phys, Sydney, NSW 2006, Australia. Smithsonian Astrophys Observ, Cambridge, MA 02138 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. RP Tuthill, PG (reprint author), Univ Sydney, Sch Phys, Sydney, NSW 2006, Australia. NR 65 TC 46 Z9 46 U1 0 U2 2 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD OCT 1 PY 2002 VL 577 IS 2 BP 826 EP 838 DI 10.1086/342235 PN 1 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 598WT UT WOS:000178300000022 ER PT J AU Corbet, RHD Mukai, K AF Corbet, RHD Mukai, K TI The orbit and position of the X-ray pulsar XTE J1855-026: An eclipsing supergiant system SO ASTROPHYSICAL JOURNAL LA English DT Article DE stars : individual (XTE J1855-026); stars : neutron; X-rays : stars ID TIMING EXPLORER OBSERVATIONS; GAS IMAGING SPECTROMETER; ASCA; PERFORMANCE AB A pulse-timing orbit has been obtained for the X-ray binary XTE J1855-026 using observations made with the Proportional Counter Array on board the Rossi X-Ray Timing Explorer (RXTE). The mass function obtained of similar to16 M. together with the detection of an extended near-total eclipse confirm that the primary star is a supergiant as predicted. The orbital eccentricity is found to be very low with a best-fit value of 0.04 +/- 0.02. The orbital period is also refined to be 6.0724 +/- 0.0009 days using an improved and extended light curve obtained with the RXTE All Sky Monitor. Observations with the ASCA satellite provide an improved source location of R.A. = 18(h)55(m)31(.)(s)3, decl. = 02degrees36'24."0 (J2000.0) with an estimated systematic uncertainty of less than 12". A serendipitous new source, AX J1855.4-0232, was also discovered during the ASCA observations. C1 Univ Space Res Assoc, Columbia, MD 21044 USA. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Corbet, RHD (reprint author), Univ Space Res Assoc, Columbia, MD 21044 USA. NR 19 TC 12 Z9 13 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD OCT 1 PY 2002 VL 577 IS 2 BP 923 EP 928 DI 10.1086/342244 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 598WT UT WOS:000178300000032 ER PT J AU Gogus, E Kouveliotou, C Woods, PM Finger, MH van der Klis, M AF Gogus, E Kouveliotou, C Woods, PM Finger, MH van der Klis, M TI A comprehensive study of pulse profile evolution in SGR 1806-20 and SGR 1900+14 with the Rossi X-Ray Timing Explorer Proportional Counter Array SO ASTROPHYSICAL JOURNAL LA English DT Article DE stars : individual (SGR 1806-20, SGR 1900+14) ID SOFT GAMMA REPEATER; 1998 AUGUST 27; SGR 1900+14; RADIATIVE MECHANISM; MAGNETIC-FIELD; GIANT FLARE; SPIN-DOWN; DISCOVERY; SGR1806-20; OUTBURSTS AB Soft gamma repeaters undergo pulse pro le changes in connection with their burst activity. Here we present a comprehensive pulse profile history of SGR 1806-20 and SGR 1900+14 in three energy bands using Rossi X-Ray Timing Explorer/Proportional Counter Array observations performed between 1996 and 2001. Using the Fourier harmonic powers of pulse profiles, we quantify the pulse shape evolution. Moreover, we determined the firms pulsed count rates (PCRs) of each pro le. We show that the pulse profiles of SGR 1806-20 remain single pulsed, showing only modest changes for most of our observing span, while those of SGR 1900+14 change remarkably in all energy bands. Highly significant pulsations from SGR 1900+14 following the 1998 August 27 and 2001 April 18 bursts enabled us to study not only the decay of PCRs in different energy bands but also their correlations with each other. C1 Univ Alabama, Dept Phys, Huntsville, AL 35899 USA. Natl Space & Technol Ctr, Huntsville, AL 35805 USA. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. Univ Amsterdam, Astron Inst Anton Pannekoek, NL-1098 SJ Amsterdam, Netherlands. Univ Amsterdam, CHEAF, NL-1098 SJ Amsterdam, Netherlands. RP Gogus, E (reprint author), Univ Alabama, Dept Phys, Huntsville, AL 35899 USA. EM ersin.gogus@msfc.nasa.gov NR 28 TC 23 Z9 23 U1 0 U2 1 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD OCT 1 PY 2002 VL 577 IS 2 BP 929 EP 939 DI 10.1086/342245 PN 1 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 598WT UT WOS:000178300000033 ER PT J AU Palmeri, P Mendoza, C Kallman, TR Bautista, MA AF Palmeri, P Mendoza, C Kallman, TR Bautista, MA TI On the structure of the iron K edge SO ASTROPHYSICAL JOURNAL LA English DT Article DE atomic processes; line : formation; line : profiles; X-rays : general ID PHOTOIONIZATION CROSS-SECTIONS; RYDBERG SERIES; AUGER DECAY; SHELL; RESONANCES; IONS AB It is shown that the commonly held view of sharp Fe K edges must be modified if the decay pathways of the resonances converging to the K thresholds are adequately taken into account. These resonances display damped Lorentzian profiles of nearly constant widths along the spectroscopic series that are smeared to impose continuity across the threshold. By modeling the effects of K damping on opacities, it is found that the broadening of the K edge grows with the ionization level of the plasma and that the appearance at high ionization of a localized absorption feature around 7.2 keV is identified as the K unresolved transition array. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Maryland, Dept Astron, College Pk, MD 20742 USA. Inst Venezolano Invest Cient, Ctr Fis, Caracas 1020A, Venezuela. RP Palmeri, P (reprint author), NASA, Goddard Space Flight Ctr, Code 662, Greenbelt, MD 20771 USA. NR 17 TC 31 Z9 31 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD OCT 1 PY 2002 VL 577 IS 2 BP L119 EP L122 DI 10.1086/344243 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 598WY UT WOS:000178300500011 ER PT J AU Stanford, SA Eisenhardt, PR Dickinson, M Holden, BP De Propris, R AF Stanford, SA Eisenhardt, PR Dickinson, M Holden, BP De Propris, R TI Optical and near-infrared photometry of distant galaxy clusters SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Article DE galaxies : clusters : general; galaxies : evolution; galaxies : formation; galaxies : high-redshift; galaxies : photometry ID HUBBLE-SPACE-TELESCOPE; HIGH-REDSHIFT CLUSTERS; MEDIUM-SENSITIVITY SURVEY; COLOR-MAGNITUDE RELATION; X-RAY DATA; LUMINOSITY EVOLUTION; POPULATIONS; MORPHOLOGY; Z=1.27; Z=0.83 AB We present optical and near-infrared photometry of 45 clusters of galaxies at 0.1 < z < 1.3. Galaxy catalogs in each cluster were defined at the longest wavelength available, generally the K band, down to approximately 2 mag below M*. We include finding chart images of the band used for catalog definition. The photometry has been used in previously published papers to examine the origin and evolution of galaxies in distant clusters. C1 Univ Calif Davis, Dept Phys, Davis, CA 95616 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Space Telescope Sci Inst, Baltimore, MD 21218 USA. Australian Natl Univ, Res Sch Astron & Astrophys, Weston, ACT 2611, Australia. RP Stanford, SA (reprint author), Lawrence Livermore Natl Lab, Inst Geophys & Planetary Phys, Livermore, CA 94550 USA. NR 39 TC 37 Z9 38 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0067-0049 J9 ASTROPHYS J SUPPL S JI Astrophys. J. Suppl. Ser. PD OCT PY 2002 VL 142 IS 2 BP 153 EP 160 DI 10.1086/340972 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 596YM UT WOS:000178194100001 ER PT J AU Shelander, D AF Shelander, D TI Composting creates positive changes at NASA Research Center SO BIOCYCLE LA English DT Article C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Shelander, D (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU JG PRESS, INC PI EMMAUS PA 419 STATE AVE, EMMAUS, PA 18049 USA SN 0276-5055 J9 BIOCYCLE JI Biocycle PD OCT PY 2002 VL 43 IS 10 BP 40 EP 41 PG 2 WC Ecology; Soil Science SC Environmental Sciences & Ecology; Agriculture GA 618LM UT WOS:000179419600026 ER PT J AU Ord, GN Gualtieri, JA AF Ord, GN Gualtieri, JA TI A realistic setting for Feynman paths SO CHAOS SOLITONS & FRACTALS LA English DT Article ID QUANTUM; CHESSBOARD; MODEL AB In the context of quantum mechanics, the physical origin of the wave function or probability amplitude is unknown, only the square modulus having a direct interpretation. Similarly, the path integral is considered a calculational tool with little connection to any external reality. Here we consider a counter-example to this general picture. We discuss a reformulation of the Feynman chessboard model which is completely realistic, allowing an examination of the physical origin of phase and Feynman paths in this simplest of cases. (C) 2002 Published by Elsevier Science Ltd. C1 Ryerson Univ, MPCS, Toronto, ON M5K 25B, Canada. NASA, Goddard Space Flight Ctr, Appl Informat Sci Branch, Greenbelt, MD 20771 USA. RP Ord, GN (reprint author), Ryerson Univ, MPCS, Toronto, ON M5K 25B, Canada. NR 27 TC 4 Z9 4 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0960-0779 J9 CHAOS SOLITON FRACT JI Chaos Solitons Fractals PD OCT PY 2002 VL 14 IS 7 BP 929 EP 935 AR PII S0960-0779(02)00043-7 DI 10.1016/S0960-0779(02)00043-7 PG 7 WC Mathematics, Interdisciplinary Applications; Physics, Multidisciplinary; Physics, Mathematical SC Mathematics; Physics GA 589QW UT WOS:000177772700001 ER PT J AU Srivastava, D Atluri, SN AF Srivastava, D Atluri, SN TI Computational nanotechnology: A current perspective SO CMES-COMPUTER MODELING IN ENGINEERING & SCIENCES LA English DT Article ID JUNCTION CARBON NANOTUBES; MOLECULAR-DYNAMICS; DEVICES AB The current status of the progress and developments in computational nanotechnology is briefly reviewed, from the perspective of its applications. The enabling tools and techniques of physics- and chemistry-based simulations, within a multi-scale context, are briefly reviewed. C1 NASA, Ames Res Ctr, Computat Nanotechnol CSC, NAS, Moffett Field, CA 94035 USA. Univ Calif Irvine, Ctr Aerosp Res & Educ, Irvine, CA 92612 USA. RP NASA, Ames Res Ctr, Computat Nanotechnol CSC, NAS, Moffett Field, CA 94035 USA. RI Atluri, Satya/C-5040-2013 OI Atluri, Satya/0000-0001-6793-9619 NR 25 TC 51 Z9 51 U1 0 U2 1 PU TECH SCIENCE PRESS PI NORCROSS PA 6825 JIMMY CARTER BLVD, STE 1850, NORCROSS, GA 30071 USA SN 1526-1492 EI 1526-1506 J9 CMES-COMP MODEL ENG JI CMES-Comp. Model. Eng. Sci. PD OCT PY 2002 VL 3 IS 5 BP 531 EP 538 PG 8 WC Engineering, Multidisciplinary; Mathematics, Interdisciplinary Applications SC Engineering; Mathematics GA 617FD UT WOS:000179350100001 ER PT J AU Globus, A Menon, M Srivastava, D AF Globus, A Menon, M Srivastava, D TI JavaGenes: Evolving molecular force field parameters with genetic algorithm SO CMES-COMPUTER MODELING IN ENGINEERING & SCIENCES LA English DT Article ID DYNAMICS SIMULATIONS; CHEMICAL-REACTIONS; SILICON; OPTIMIZATION; SCHEME; FILMS AB A genetic algorithm procedure has been developed for fitting parameters for many-body interatomic force field functions. Given a physics or chemistry based analytic form for the force field function, parameters are typically chosen to,fit a range of structural and physical properties given either by experiments and/or by higher accuracy tight-binding or ab-initio simulations. The method involves using both near equilibrium and far from equilibrium configurations in the fitting procedure, and is unlikely to be trapped in local minima in the complex many-dimensional parameter space. As a proof of concept, we demonstrate the procedure for Stillinger-Weber (S-W) potential by (a) reproducing the published parameters for Si by using S-W energetics in the fitness function, and (b) evolving a "new" set of parameters, with a fitness function based on a non-orthogonal tight-binding method, which are better suited for Si cluster energetics as compared to the published S-W potential. Evolution is driven by a fitness function based on the energies and forces calculated for Si, clusters (n < 7), and is able to predict accurate energies for minimum energy and deformed configurations of Si, (n = 7, 8, 33) clusters, which were not used in the fitness function. C1 NASA, Ames Res Ctr, CSC, NAS, Moffett Field, CA 94035 USA. Univ Kentucky, Dept Phys, Lexington, KY 40506 USA. Univ Kentucky, Ctr Computat Sci, Lexington, KY 40506 USA. RP Globus, A (reprint author), NASA, Ames Res Ctr, CSC, NAS, Moffett Field, CA 94035 USA. NR 21 TC 7 Z9 7 U1 0 U2 2 PU TECH SCIENCE PRESS PI PALMDALE PA PO BOX 900486, PALMDALE, CA 93590-0486 USA SN 1526-1492 J9 CMES-COMP MODEL ENG JI CMES-Comp. Model. Eng. Sci. PD OCT PY 2002 VL 3 IS 5 BP 557 EP 574 PG 18 WC Engineering, Multidisciplinary; Mathematics, Interdisciplinary Applications SC Engineering; Mathematics GA 617FD UT WOS:000179350100003 ER PT J AU Klimeck, G Oyafuso, F Boykin, TB Bowen, RC von Allmen, P AF Klimeck, G Oyafuso, F Boykin, TB Bowen, RC von Allmen, P TI Development of a nanoelectronic 3-D (NEMO 3-D) simulator for multimillion atom simulations and its application to alloyed quantum dots SO CMES-COMPUTER MODELING IN ENGINEERING & SCIENCES LA English DT Article DE quantum dot; alloy; nanoelectronic; sparse matrix-vector multiplication; tight-binding; optical transition; simulation ID TIGHT-BINDING PARAMETERS; ELECTRONIC-STRUCTURE; COULOMB-BLOCKADE; SEMICONDUCTORS; MODELS; PSEUDOPOTENTIALS; CONDUCTANCE; TRANSPORT; WELL; SI AB Material layers with a thickness of a few nanometers are common-place in today's semiconductor devices. Before long, device fabrication methods will reach a point at which the other two device dimensions are scaled down to few tens of nanometers. The total atom count in such deca-nano devices is reduced to a few million. Only a small finite number of "free" electrons will operate such nano-scale devices due to quantized electron energies and electron charge. This work demonstrates that the simulation of electronic structure and electron transport on these length scales must not only be fundamentally quantum mechanical, but it must also include the atomic granularity of the device. Various elements of the theoretical, numerical, and software foundation of the prototype development of a Nanoelectronic Modeling tool (NEMO 3-D) which enables this class of device simulation on Beowulf cluster computers are presented. The electronic system is represented in a sparse complex Hamiltonian matrix of the order of hundreds of millions. A custom parallel matrix vector multiply algorithm that is coupled to a Lanczos and/or RayleighRitz eigenvalue solver has been developed. Benchmarks of the parallel electronic structure and the parallel strain calculation performed on various Beowulf cluster computers and a SGI Origin 2000 are presented. The Beowulf cluster benchmarks show that the competition for memory access on dual CPU PC boards renders the utility of one of the CPUs useless, if the memory usage per node is about 1-2 GB. A new strain treatment for the sp(3)s* and sp(3)d(5)s* tight-binding models is developed and parameterized for bulk material properties of GaAs and InAs. The utility of the new tool is demonstrated by an atomistic analysis of the effects of disorder in alloys. In particular bulk InxGa1-xAs and In0.6Ga0.4As quantum dots are examined. The quantum dot simulations show that the random atom configurations in the alloy, without any size or shape variations can lead to optical transition energy variations of several meV. The electron and hole wave functions show significant spatial variations due to spatial disorder indicating variations in electron and hole localization. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Alabama, Dept Elect & Comp Engn, Huntsville, AL 35899 USA. Univ Alabama, LICOS, Huntsville, AL 35899 USA. Motorola Labs, Solid State Res Ctr, Tempe, AZ 85284 USA. RP CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM gekco@jpl.nasa.gov RI Fonseca, James/G-1018-2011; Klimeck, Gerhard/A-1414-2012 OI Klimeck, Gerhard/0000-0001-7128-773X NR 85 TC 153 Z9 153 U1 0 U2 10 PU TECH SCIENCE PRESS PI NORCROSS PA 6825 JIMMY CARTER BLVD, STE 1850, NORCROSS, GA 30071 USA SN 1526-1492 EI 1526-1506 J9 CMES-COMP MODEL ENG JI CMES-Comp. Model. Eng. Sci. PD OCT PY 2002 VL 3 IS 5 BP 601 EP 642 PG 42 WC Engineering, Multidisciplinary; Mathematics, Interdisciplinary Applications SC Engineering; Mathematics GA 617FD UT WOS:000179350100006 ER PT J AU Brenner, DW Shenderova, OA Areshkin, DA Schall, JD Frankland, SJV AF Brenner, DW Shenderova, OA Areshkin, DA Schall, JD Frankland, SJV TI Atomic modeling of carbon-based nanostructures as a tool for developing new materials and technologies SO CMES-COMPUTER MODELING IN ENGINEERING & SCIENCES LA English DT Article DE molecular dynamics; tight-binding; simulation; nanotube; nanorod; diamond; composites; hydrogen storage ID HYDROGEN ADSORPTION; ELECTRONIC-PROPERTIES; MOLECULAR-DYNAMICS; TIGHT-BINDING; MECHANICAL-PROPERTIES; FULLERENE NANOTUBES; NANODIAMOND POWDER; DIAMOND SURFACES; GRAPHITE; SIMULATIONS AB The derivation of a bond-order potential energy function and a self-consistent tight-binding scheme is presented, followed by a survey of the application of these methods to calculating properties of carbon nanostructures. The modeling studies discussed include properties of functionalized and kinked carbon nanotubes, Raman shifts for hydrogen stored in nanotubes, nanotubes in a composite, properties of nanotubes in applied potential (electrical) fields, and structures and properties of nanocones, nanodiamond clusters and rods, and hybrid diamond-nanotube structures. C1 N Carolina State Univ, Dept Mat Sci & Engn, Raleigh, NC 27695 USA. NASA, Langley Res Ctr, Hampton, VA 23669 USA. RP Brenner, DW (reprint author), N Carolina State Univ, Dept Mat Sci & Engn, Raleigh, NC 27695 USA. RI Brenner, Donald/D-1741-2009 NR 74 TC 35 Z9 35 U1 1 U2 8 PU TECH SCIENCE PRESS PI PALMDALE PA PO BOX 900486, PALMDALE, CA 93590-0486 USA SN 1526-1492 J9 CMES-COMP MODEL ENG JI CMES-Comp. Model. Eng. Sci. PD OCT PY 2002 VL 3 IS 5 BP 643 EP 673 PG 31 WC Engineering, Multidisciplinary; Mathematics, Interdisciplinary Applications SC Engineering; Mathematics GA 617FD UT WOS:000179350100007 ER PT J AU Yang, L Han, J Anantram, MP Jaffe, RL AF Yang, L Han, J Anantram, MP Jaffe, RL TI Bonding geometry and bandgap changes of carbon nanotubes under uniaxial and torsional strain SO CMES-COMPUTER MODELING IN ENGINEERING & SCIENCES LA English DT Article ID ELECTRONIC-STRUCTURE; TUBULES AB Bonding geometry and bandgap of carbon nantotubes under uniaxial and torsional deformation are studied computationally for nanotubes of various chiralities and diameters. Bonding geometries are obtained with Tersoff-Brenner potential from molecular mechanics simulations. Bandgaps as function of strain are calculated from the molecular mechanics structures using one (p) and four (2s and 2p(x), 2p(y), 2p(z)) orbital tight-binding models. For small strains, the bandgap results are qualitatively consistent with those predicted by the one orbital analytical model. Response of the electronic properties of nanotubes to large strains is characterized by a change in sign of d(bandgap)/d(strain). These originate from either quantum number or bonding geometry effects, and are strain-induced semiconductor-metal transitions. The effect of variations in bonding geometries between continuum mechanics and molecular mechanics structures on the electronic properties and differences between the one and four orbital models are also presented. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Yang, L (reprint author), NASA, Ames Res Ctr, Mail Stop 230, Moffett Field, CA 94035 USA. NR 18 TC 8 Z9 8 U1 1 U2 2 PU TECH SCIENCE PRESS PI PALMDALE PA PO BOX 900486, PALMDALE, CA 93590-0486 USA SN 1526-1492 J9 CMES-COMP MODEL ENG JI CMES-Comp. Model. Eng. Sci. PD OCT PY 2002 VL 3 IS 5 BP 675 EP 685 PG 11 WC Engineering, Multidisciplinary; Mathematics, Interdisciplinary Applications SC Engineering; Mathematics GA 617FD UT WOS:000179350100008 ER PT J AU Gu, Y Rothe, EW Reck, GP Locke, RJ Anderson, RC Hicks, YR Nguyen, QV AF Gu, Y Rothe, EW Reck, GP Locke, RJ Anderson, RC Hicks, YR Nguyen, QV TI One-dimensional UV-Raman imaging of a Jet-A-fueled aircraft combustor in a high temperature and pressure test cell: A feasibility study SO COMBUSTION SCIENCE AND TECHNOLOGY LA English DT Article DE Raman spectroscopy; nonintrusive optical diagnostics; high-pressure combustion ID LASER-LIGHT; NARROW-BAND; 248 NM; SCATTERING; DIAGNOSTICS AB UV-Raman diagnostics are complementary to other laser-based methods. We obtained one-dimensional Raman images from the flow in a high-pressure aircraft combustor. They were acquired from both single and multiple laser shots. Our goal was to see whether excimer-based Raman would work in spite of severe combustor conditions. The Jet-A fuel that was used causes difficulties because it contains polyaromatic hydrocarbons (PAHs). Some fundamental problems might have prevented successful Raman imaging. These include (1) vaporized PAHs that can absorb much of the UV laser light, thereby weakening the laser beam; (2) PAH fluorescence that increases noise; and (3) fuel droplets that absorb and refract light and produce intense light scattering. The test rig was available for only one day. Nevertheless, the results show that a one-dimensional UV-Raman imaging method can diagnose such a combustor, operating at realistic conditions, even with single shots. We suggest some diagnostic improvements that could increase the precision considerably in future applications. C1 Wayne State Univ, Dept Chem Engn & Mat Sci, Detroit, MI 48202 USA. Venture Lighting, Cleveland, OH USA. NASA, Glenn Res Ctr, Cleveland, OH USA. RP Rothe, EW (reprint author), Wayne State Univ, Dept Chem Engn & Mat Sci, Detroit, MI 48202 USA. NR 19 TC 7 Z9 7 U1 0 U2 4 PU TAYLOR & FRANCIS LTD PI ABINGDON PA 4 PARK SQUARE, MILTON PARK, ABINGDON OX14 4RN, OXON, ENGLAND SN 0010-2202 J9 COMBUST SCI TECHNOL JI Combust. Sci. Technol. PD OCT PY 2002 VL 174 IS 10 BP 199 EP 215 DI 10.1080/00102200290021506 PG 17 WC Thermodynamics; Energy & Fuels; Engineering, Multidisciplinary; Engineering, Chemical SC Thermodynamics; Energy & Fuels; Engineering GA 613ZW UT WOS:000179163200010 ER PT J AU Wang, ZJ Przekwas, AJ Liu, Y AF Wang, ZJ Przekwas, AJ Liu, Y TI A FV-TD electromagnetic solver using adaptive Cartesian grids SO COMPUTER PHYSICS COMMUNICATIONS LA English DT Article DE computational electromagnetics; finite volume method; adaptive Cartesian grid ID SCATTERING; EQUATIONS AB A second-order finite-volume (FV) method has been developed to solve the time-domain (TD) Maxwell equations, which govern the dynamics of electromagnetic waves. The computational electromagnetic (CEM) solver is capable of handling arbitrary grids, including structured, unstructured, and adaptive Cartesian grids, which are topologically arbitrary. It is argued in this paper that the adaptive Cartesian grid is better than a tetrahedral grid for complex geometries considering both efficiency and accuracy. A cell-wise linear reconstruction scheme is employed to achieve second-order spatial accuracy. Second-order time accuracy is obtained through a two-step Runge-Kutta scheme. Issues on automatic adaptive Cartesian grid generation such as cell-cutting and cell-merging are discussed. A multi-dimensional characteristic absorbing boundary condition (MDC-ABC) is developed at the truncated far-field boundary to reduce reflected waves from this artificial boundary. The CEM solver is demonstrated with several test cases with analytical solutions. (C) 2002 Elsevier Science B.V. All rights reserved. C1 Michigan State Univ, Dept Mech Engn, E Lansing, MI 48824 USA. CFD Res Crop, Huntsville, AL 35805 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Wang, ZJ (reprint author), Michigan State Univ, Dept Mech Engn, E Lansing, MI 48824 USA. RI Wang, Z.J./A-9628-2010 OI Wang, Z.J./0000-0002-6203-6303 NR 25 TC 15 Z9 15 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0010-4655 J9 COMPUT PHYS COMMUN JI Comput. Phys. Commun. PD OCT 1 PY 2002 VL 148 IS 1 BP 17 EP 29 DI 10.1016/S0010-4655(02)00464-2 PG 13 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA 604FG UT WOS:000178605500002 ER PT J AU Perry, JN Liebhold, AM Rosenberg, MS Dungan, J Miriti, M Jakomulska, A Citron-Pousty, S AF Perry, JN Liebhold, AM Rosenberg, MS Dungan, J Miriti, M Jakomulska, A Citron-Pousty, S TI Illustrations and guidelines for selecting statistical methods for quantifying spatial pattern in ecological data SO ECOGRAPHY LA English DT Article ID POPULATION-DYNAMICS; COUNT DATA; AUTOCORRELATION; MODELS; CORRELOGRAM; DEPENDENCE; MORTALITY; DENSITY; EDGE AB This paper aims to provide guidance to ecologists with limited experience in spatial analysis to help in their choice of techniques, It uses examples to compare methods of spatial analysis for ecological field data. A taxonomy of different data types is presented, including point- and area-referenced data, with and without attributes. Spatially and non-spatially explicit data are distinguished. The effects of sampling and other transformations that convert one data type to another are discussed; the possible loss of spatial information is considered. Techniques for analyzing spatial pattern, developed in plant ecology, animal ecology, landscape ecology, geostatistics and applied statistics are reviewed briefly and their overlap in methodology and philosophy noted. The techniques are categorized according to their output and the inferences that may be drawn from them, in a discursive style without formulae. Methods are compared for four case studies with field data covering a range of types. These are: 1) percentage cover of three shrubs along a line transect 2) locations and volume of a desert plant in a I ha area: 3) a remotely-sensed spectral index and elevation from 10(5) km(2) of a mountainous region; and 4) land cover from three rangeland types within 800 km2 of a coastal region. Initial approaches utilize mapping, frequency distributions and variance-mean indices. Analysis techniques we compare include: local quadrat variance, block, quadrat variance, correlograms, variograms, angular correlation, directional variograms, wavelets, SADIE, nearest neighbour methods, Ripley's L(t), and various landscape ecology metrics. Our advice to ecologists is to use simple visualization techniques for initial analysis, and subsequently to select methods that are appropriate for the data type and that answer their specific questions of interest, It is usually prudent to employ several different techniques. C1 Rothamsted Expt Stn, PIE Div, Harpenden AL5 2JQ, Herts, England. USDA, Forest Serv, NE Res Stn, Morgantown, WV 26505 USA. Arizona State Univ, Dept Biol, Tempe, AZ 85287 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. SUNY Stony Brook, Dept Ecol & Evolut, Stony Brook, NY 11794 USA. Univ Warsaw, Remote Sensing Environm Lab, Fac Geog & Reg Studies, PL-0092 Warsaw, Poland. Univ Connecticut, Dept Ecol & Evolut Biol, Storrs, CT 06269 USA. RP Perry, JN (reprint author), Rothamsted Expt Stn, PIE Div, Harpenden AL5 2JQ, Herts, England. RI Liebhold, Andrew/C-1423-2008; perry, joe/B-2729-2010; Rosenberg, Michael/A-4621-2008; Dungan, Jennifer/G-9921-2016 OI Liebhold, Andrew/0000-0001-7427-6534; Rosenberg, Michael/0000-0001-7882-2467; Dungan, Jennifer/0000-0002-4863-1616 NR 89 TC 262 Z9 284 U1 12 U2 135 PU BLACKWELL MUNKSGAARD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0906-7590 J9 ECOGRAPHY JI Ecography PD OCT PY 2002 VL 25 IS 5 BP 578 EP 600 DI 10.1034/j.1600-0587.2002.250507.x PG 23 WC Biodiversity Conservation; Ecology SC Biodiversity & Conservation; Environmental Sciences & Ecology GA 590HR UT WOS:000177814100007 ER PT J AU Dungan, JL Perry, JN Dale, MRT Legendre, P Citron-Pousty, S Fortin, MJ Jakomulska, A Miriti, M Rosenberg, MS AF Dungan, JL Perry, JN Dale, MRT Legendre, P Citron-Pousty, S Fortin, MJ Jakomulska, A Miriti, M Rosenberg, MS TI A balanced view of scale in spatial statistical analysis SO ECOGRAPHY LA English DT Article ID LANDSCAPE ECOLOGY; PLANT COMMUNITY; SAMPLING UNITS; SIZE; PATTERN; HETEROGENEITY; VARIANCE; DESIGN AB Concepts of spatial scale, such as extent, grain, resolution, range, footprint, support and cartographic ratio are not interchangeable. Because of the potential confusion among the definitions of these terms, we suggest that authors avoid the term "scale" and instead refer to specific concepts. In particular, we are careful to discriminate between observation scales, scales of ecological phenomena and scales used in spatial statistical analysis. When scales of observation or analysis change, that is, when the unit size, shape, spacing or extent are altered, statistical results are expected to change. The kinds of results that may change include estimates of the population mean and variance, the strength and character of spatial autocorrelation and spatial anisotropy, patch and gap sizes and multivariate relationships, The First three of these results (precision of the mean, variance and spatial autocorrelation) can sometimes be estimated using geostatistical support-effect models. We present four case studies of organism abundance and cover illustrating some of these changes and how conclusions about ecological phenomena (process and structure) may be affected. We identify the influence of observational scale on statistical results as a subset of what geographers call the Modifiable Area Unit Problem (MAUP). The way to avoid the MAUP is by careful construction of sampling design and analysis. We recommend a set of considerations for sampling design to allow useful tests for specific scales of a phenomenon under study. We further recommend that ecological studies completely report all components of observation and analysis scales to increase the possibility of cross-study comparisons. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Rothamsted Expt Stn, Plant & Invertebrate Ecol Div, Harpenden AL5 2JQ, Herts, England. Univ Alberta, Dept Biol Sci, Edmonton, AB T6G 2E9, Canada. Univ Montreal, Dept Biol Sci, Montreal, PQ H3C 3J7, Canada. Yale Univ, Social Sci Statlab, New Haven, CT 06520 USA. Univ Toronto, Dept Zool, Toronto, ON M5S 3G5, Canada. Univ Warsaw, Remote Sensing Environm Lab, Fac Geog & Reg Studies, PL-00927 Warsaw, Poland. Ohio State Univ, Dept Ecol Evolut & Organismal Biol, Columbus, OH 43210 USA. Arizona State Univ, Dept Biol, Tempe, AZ 85287 USA. RP Dungan, JL (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RI perry, joe/B-2729-2010; Rosenberg, Michael/A-4621-2008; Dungan, Jennifer/G-9921-2016 OI Rosenberg, Michael/0000-0001-7882-2467; Dungan, Jennifer/0000-0002-4863-1616 NR 51 TC 346 Z9 385 U1 19 U2 153 PU BLACKWELL MUNKSGAARD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0906-7590 J9 ECOGRAPHY JI Ecography PD OCT PY 2002 VL 25 IS 5 BP 626 EP 640 DI 10.1034/j.1600-0587.2002.250510.x PG 15 WC Biodiversity Conservation; Ecology SC Biodiversity & Conservation; Environmental Sciences & Ecology GA 590HR UT WOS:000177814100010 ER PT J AU Tatara, CP Mulvey, M Newman, MC AF Tatara, CP Mulvey, M Newman, MC TI Genetic and demographic responses of mercury-exposed mosquitofish (Gambusia holbrooki) populations: Temporal stability and reproductive components of fitness SO ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY LA English DT Article DE Gambusia holbrooki; genetics; mercury; selection; fitness ID ALLOZYME GENOTYPE; INORGANIC MERCURY; AFFINIS BAIRD; GIRARD; TIME; VERIFICATION; FREQUENCIES; SELECTION; ALLELE; DEATH AB Two previous mesocosm studies showed changes in glucosephospbate isomerase-2 (Gpi-2) allele frequencies in mosquitofish Populations exposed to mercury for I I Id or two years. A previous selection component analysis of single-gene ration populations exposed for I I I d to 18 mug/L Hg suggested that female sexual selection and fecundity selection could contribute to changes in Gpi-2 allele frequencies. The present multigeneration study was conducted to determine! the stability of Gpi-2 allele frequencies over four years of mercury exposure. measure the reproductive fitness of Gpi-2 genotypes inhabiting control and mercury-contaminated mesocosms to determine a mechanism explaining changes in Gpi-2 allele frequencies, investigate differences in the demographic characteristics of mercury-exposed and control populations, and investigate the water quality of the mesocosms to determine if variables other than mercury show concordant patterns among, mesocosms. Differences in Gpi-2 allele frequencies between control and mercury-exposed populations were stable over four years (similar to eight generations) of mercury exposure. Mercury-exposed female mosquitofish had a lower probability of being gravid than control females (p = 0.001). Mercury-exposed females also had lower fecundity (total number of eggs and embryos) than control females (p = 0.036). Unlike the results of the more intense mercury exposures in the single generation study. no strong evidence was found that Gpi-2 genotype influenced fecundity or the probability of being gravid in both control and mecury-exposed females. The quantification of fitness components is difficult but has the potential to enhance our understanding of how toxicants alter allele frequencies in exposed populations. C1 Natl Marine Fisheries Serv, Manchester Res Stn, Manchester, WA 98353 USA. Coll William & Mary, Sch Marine Sci, Virginia Inst Marine Sci, Gloucester Point, VA 23062 USA. RP Tatara, CP (reprint author), Natl Marine Fisheries Serv, Manchester Res Stn, POB 130, Manchester, WA 98353 USA. NR 27 TC 11 Z9 12 U1 0 U2 8 PU SETAC PI PENSACOLA PA 1010 NORTH 12TH AVE, PENSACOLA, FL 32501-3367 USA SN 0730-7268 J9 ENVIRON TOXICOL CHEM JI Environ. Toxicol. Chem. PD OCT PY 2002 VL 21 IS 10 BP 2191 EP 2197 DI 10.1897/1551-5028(2002)021<2191:GADROM>2.0.CO;2 PG 7 WC Environmental Sciences; Toxicology SC Environmental Sciences & Ecology; Toxicology GA 596FJ UT WOS:000178153300024 PM 12371497 ER PT J AU Hobbs, A Williamson, A AF Hobbs, A Williamson, A TI Unsafe acts and unsafe outcomes in aircraft maintenance SO ERGONOMICS LA English DT Article DE error; mistake; violation; accident; maintenance; safety ID OCCUPATIONAL ACCIDENTS; INDIVIDUAL-DIFFERENCES; BEHAVIOR; ERRORS; VIOLATIONS; INVOLVEMENT; SAFETY; MODELS; RULE AB Road safety studies using the Driver Behaviour Questionnaire (DBQ) have provided support for a three-way distinction between violations, skill-based errors and mistakes, and have indicated that a tendency to commit driving violations is associated with an increased risk of accident involvement. The aims of this study were to examine whether the three-way distinction of unsafe acts is applicable in the context of aircraft maintenance, and whether involvement in maintenance safety occurrences can be predicted on the basis of self-reported unsafe acts. A Maintenance Behaviour Questionnaire (MBQ) was developed to explore patterns of unsafe acts committed by aircraft maintenance mechanics. The MBQ was completed anonymously by over 1300 Australian aviation mechanics, who also provided information on their involvement in workplace accidents and incidents. Four factors were identified: routine violations, skill-based errors, mistakes and exceptional violations. Violations and mistakes were related significantly to the occurrence of incidents that jeopardized the quality of aircraft maintenance, but were not related to workplace injuries. Skill-based errors, while not related to work quality incidents, were related to workplace injuries. The results are consistent with the three-way typology of unsafe acts described by Reason et al. (1990) and with the DBQ research indicating an association between self-reported violations and accidents. The current findings suggest that interventions addressed at maintenance quality incidents should take into account the role of violations and mistakes, and the factors that promote them. In contrast, interventions directed at reducing workplace injury are likely to require a focus on skill-based errors. C1 Bur Air Safety Invest, Canberra, ACT, Australia. NSW Injury Risk Management Res Ctr, Sydney, NSW, Australia. RP Hobbs, A (reprint author), San Jose State Univ, NASA, Ames Res Ctr, MS262-4 Moffett Field, Moffett Field, CA 94035 USA. NR 36 TC 17 Z9 17 U1 1 U2 12 PU TAYLOR & FRANCIS LTD PI ABINGDON PA 4 PARK SQUARE, MILTON PARK, ABINGDON OX14 4RN, OXON, ENGLAND SN 0014-0139 J9 ERGONOMICS JI Ergonomics PD OCT PY 2002 VL 45 IS 12 BP 866 EP 882 DI 10.1080/00140130210148528 PG 17 WC Engineering, Industrial; Ergonomics; Psychology, Applied; Psychology SC Engineering; Psychology GA 615JW UT WOS:000179242900005 PM 12487688 ER PT J AU Grafton, ST Hazeltine, E Ivry, RB AF Grafton, ST Hazeltine, E Ivry, RB TI Motor sequence learning with the nondominant left hand - A PET functional imaging study SO EXPERIMENTAL BRAIN RESEARCH LA English DT Article DE blood flow; imaging; laterality; brain; human ID HEMISPHERIC-ASYMMETRY; CEREBRAL-DOMINANCE; IDEOMOTOR APRAXIA; PERFORMANCE; CORTEX; HANDEDNESS; MOVEMENT; REPRESENTATIONS; SELECTION; LESIONS AB Whereas the human right hemisphere is active during execution of contralateral hand movements, the left hemisphere is engaged for both contra- and ipsilateral movements, at least for right-handed subjects. Whether this asymmetry is also found during motor learning remains unknown. Implicit sequence learning by the nondominant left hand was examined with the serial reaction time (SRT) task during functional brain imaging. As learning progressed, increases in brain activity were observed in left lateral premotor cortex (PMC) and bilaterally in supplementary motor areas (SMA), with the increase significantly greater in the left hemisphere. The left SMA site was similar to one previously identified with right-hand learning, suggesting that this region is critical for representing a sequence independent of effector. Learning with the left hand also recruited a widespread set of temporal and frontal regions, suggesting that motor skill learning with the nondominant hand develops within both cognitive and motor-related functional networks. After skill acquisition, subjects performed the SRT task with their right hands, and sequence transfer was tested with the original and a mirror-ordered sequence. With the original sequence, the stimulus sequence and series of response locations remained unchanged, but the finger movements were different. With the mirror-ordered sequence, the response sequence involved finger movements homologous to those used during training. Performance of the original and mirror sequence by the right hand was significantly better than with random stimuli. Mirror transformation of the sequence by the right hand was associated with a marked increase in regional activity in the left motor cortex, consistent with a role for sequential transformation at this level of the motor output pathway. C1 Dartmouth Coll, Dept Psychol & Brain Sci, Ctr Cognit Neurosci, Hanover, NH 03755 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ Calif Berkeley, Dept Psychol, Berkeley, CA 94720 USA. RP Grafton, ST (reprint author), Dartmouth Coll, Dept Psychol & Brain Sci, Ctr Cognit Neurosci, 6162 Moore Hall, Hanover, NH 03755 USA. FU NINDS NIH HHS [NS 33504] NR 48 TC 215 Z9 223 U1 1 U2 13 PU SPRINGER-VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0014-4819 J9 EXP BRAIN RES JI Exp. Brain Res. PD OCT PY 2002 VL 146 IS 3 BP 369 EP 378 DI 10.1007/s00221-002-1181-y PG 10 WC Neurosciences SC Neurosciences & Neurology GA 605VW UT WOS:000178698600010 PM 12232693 ER PT J AU Lepicovsky, J Bencic, TJ AF Lepicovsky, J Bencic, TJ TI Use of pressure-sensitive paint for diagnostics in turbomachinery flows with shocks SO EXPERIMENTS IN FLUIDS LA English DT Article ID LUMINESCENT COATINGS AB The technology of pressure-sensitive paint (PSP) is well established in external aerodynamics. In internal flows in narrow channels and in turbomachinery cascades, however, there are still unresolved problems. In particular, the internal flows with complex shock structures inside highly curved channels present a challenge. It is not always easy and straightforward to distinguish between true signals and 'ghost' images due to multiple internal reflections in narrow channels. To address some of the problems, investigations were first carried out in a narrow supersonic channel of Mach number 2.5. A single wedge or a combination of two wedges was used to generate a complex shock wave structure in the flow. The experience gained in a small supersonic channel was used for surface pressure measurements on the stator vane of a supersonic throughflow fan. The experimental results for several fan operating conditions are shown in a concise form, including performance map test points, midspan static tap pressure distributions, and vane suction side pressure fields. Finally, the PSP technique was used in the NASA transonic flutter cascade to compliment flow visualization data and to acquire backwall pressure fields to assess the cascade flow periodicity. Lessons learned from this investigation and shortcomings of the PSP technology for internal flow application are presented in the conclusion of the paper. C1 NASA, Glenn Res Ctr, QSS Grp, Cleveland, OH 44135 USA. RP Lepicovsky, J (reprint author), NASA, Glenn Res Ctr, QSS Grp, Cleveland, OH 44135 USA. NR 19 TC 8 Z9 11 U1 2 U2 10 PU SPRINGER-VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0723-4864 J9 EXP FLUIDS JI Exp. Fluids PD OCT PY 2002 VL 33 IS 4 BP 531 EP 538 DI 10.1007/s00348-002-0476-x PG 8 WC Engineering, Mechanical; Mechanics SC Engineering; Mechanics GA 611EL UT WOS:000179003400005 ER PT J AU Hannah, RW Parker, SJ Fruh, EL AF Hannah, RW Parker, SJ Fruh, EL TI Length and age at maturity of female petrale sole (Eopsetta jordani) determined from samples collected prior to spawning aggregation SO FISHERY BULLETIN LA English DT Article ID LIFE-HISTORY PARAMETERS; OVARIAN DEVELOPMENT; OREGON; COAST AB The problem of bias in female petrale sole age and length-at-maturity relationships caused by sampling from spawning aggregations was investigated. Samples were collected prior to aggregation, and histological methods were used to determine maturity status. Mature and immature fish were classified by inspecting oocytes for the presence of yolk in September, when substantial divergence in yolked and unyolked oocyte diameters had been observed. Comparison of macroscopic and microscopic assessment of maturity showed that maturity status cannot be determined accurately by using macroscopic inspection during the summer. Female petrale sole from the central Oregon coast were 50% mature at 33 cm and 5 years of age. Comparison of data from our study with data used in recent petrale sole stock assessments showed that both sampling bias and the use of samples from seasons when status cannot be accurately determined have likely caused errors in fitted maturity relationships. C1 Oregon Dept Fish & Wildlife, Marine Resources Program, Newport, OR 97365 USA. Natl Marine Fisheries Serv, NW Sci Ctr, Fisheries Res & Monitoring Div, Newport, OR 97365 USA. RP Hannah, RW (reprint author), Oregon Dept Fish & Wildlife, Marine Resources Program, 2040 Marine Sci Dr, Newport, OR 97365 USA. NR 14 TC 3 Z9 3 U1 0 U2 0 PU NATL MARINE FISHERIES SERVICE SCIENTIFIC PUBL OFFICE PI SEATTLE PA 7600 SAND POINT WAY NE BIN C15700, SEATTLE, WA 98115 USA SN 0090-0656 J9 FISH B-NOAA JI Fish. Bull. PD OCT PY 2002 VL 100 IS 4 BP 711 EP 719 PG 9 WC Fisheries SC Fisheries GA 613KC UT WOS:000179130600006 ER PT J AU Work, TM Balazs, GH AF Work, TM Balazs, GH TI Necropsy findings in sea turtles taken as bycatch in the North Pacific longline fishery SO FISHERY BULLETIN LA English DT Article ID GREEN TURTLES; DERMOCHELYS-CORIACEA; FIBROPAPILLOMATOSIS C1 US Geol Survey, Natl Wildlife Hlth Ctr, Hawaii Field Stn, Honolulu, HI 96850 USA. NOAA, Natl Marine Fisheries Serv, Honolulu Lab, SW Fisheries Sci Ctr, Honolulu, HI 96822 USA. RP Work, TM (reprint author), US Geol Survey, Natl Wildlife Hlth Ctr, Hawaii Field Stn, 300 Ala Moana Blvd,Room 5-231, Honolulu, HI 96850 USA. RI Work, Thierry/F-1550-2015 OI Work, Thierry/0000-0002-4426-9090 NR 22 TC 16 Z9 19 U1 0 U2 7 PU NATL MARINE FISHERIES SERVICE SCIENTIFIC PUBL OFFICE PI SEATTLE PA 7600 SAND POINT WAY NE BIN C15700, SEATTLE, WA 98115 USA SN 0090-0656 J9 FISH B-NOAA JI Fish. Bull. PD OCT PY 2002 VL 100 IS 4 BP 876 EP 880 PG 5 WC Fisheries SC Fisheries GA 613KC UT WOS:000179130600019 ER PT J AU Johnston, WE AF Johnston, WE TI Computational and data Grids in large-scale science and engineering SO FUTURE GENERATION COMPUTER SYSTEMS LA English DT Article DE grids; heterogeneous; widely distributed computing; NASA's information power grid (IPG); DOE science grid; grid applications AB As the practice of science moves beyond the single investigator due to the complexity of the problems that now dominate science, large collaborative and multi-institutional teams are needed to address these problems. In order to support this shift in science, the computing and data-handling infrastructure that is essential to most of modem science must also change in order to support this increased complexity. This is the goal of computing and data Grids: software infrastructure that facilitates solving large-scale problems by providing the mechanisms to access, aggregate, and manage the computer network-based infrastructure of science. This infrastructure includes computing systems, data archive systems, scientific instruments, and computer-mediated human collaborations. This paper examines several large-scale science problems, their requirements for computing and data Grid infrastructure, and the current approaches to providing the necessary functionality. Published by Elsevier Science B.V. C1 Lawrence Berkeley Natl Lab, Natl Energy Res Sci Comp Div, Berkeley, CA 94720 USA. NASA, Ames Res Ctr, Berkeley, CA 94720 USA. RP Johnston, WE (reprint author), Lawrence Berkeley Natl Lab, Natl Energy Res Sci Comp Div, 1 Cyclotron Rd,MS 50B-2239, Berkeley, CA 94720 USA. NR 29 TC 29 Z9 31 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0167-739X J9 FUTURE GENER COMP SY JI Futur. Gener. Comp. Syst. PD OCT PY 2002 VL 18 IS 8 BP 1085 EP 1100 AR PII S0167-739X(02)00087-0 DI 10.1016/S0167-739X(02)00087-0 PG 16 WC Computer Science, Theory & Methods SC Computer Science GA 608PU UT WOS:000178856200009 ER PT J AU Marks, SK Vitek, JD Giardino, JR McQueen, KC AF Marks, SK Vitek, JD Giardino, JR McQueen, KC TI Creating curricular change: needs in grades 8-12 earth science SO GEOMORPHOLOGY LA English DT Article; Proceedings Paper CT 30th Annual Binghamton Geomorphology Symposium CY NOV 12-14, 1999 CL BINGHAMTON, NEW YORK DE earth science education; teacher training; The World Wide Web; field experiences ID EDUCATION AB The realization that we do not control nature is often associated with devastating loss of life and property. Apparently. humans do not learn from their mistakes, because human tragedies seem to happen repeatedly and minimal modification of human behavior appears to transpire. Because people do not understand the dynamic nature of Earth, and Earth processes, specific education to understand and to comprehend the cause and effect of a dynamic earth is needed, The strong economic base and a high literacy rate within the USA should contribute to the ability of the K-12 educational system to create more appropriate human behavior and response to processes shaping Earth. Today major efforts are underway in government agencies, professional societies, universities and by individuals to change what and how students learn Ebout the environment. Curricular reform has been established as new national standards for what students should learn in science in grades K-12. Just having standards, however, does not guarantee implementation, improved teaching by teachers, or increased understanding by students. Science faculties must accept the challenge to provide the pedagogical education for K-12 teachers; teachers must be trained and empowered to implement change, this change must ripple throughout the entire K-12 system. Workshops and innovative materials to support renovations in the curricula are essential to affect change. The World Wide Web will be a major help in information dissemination. However, for success to be achieved, local involvement is fundamental. People with expertise about Earth can have the greatest impact on effecting change by helping neighbors acquire knowledge of the dynamic environment of Earth. The same people (namely you) must become pro-active in K-12 education. (C) 2002 Elsevier Science B.V. All rights reserved. C1 Oklahoma State Univ, Dept Acad Affairs, Stillwater, OK 74078 USA. Oklahoma State Univ, Sch Geol, Stillwater, OK 74078 USA. Oklahoma State Univ, NASA, AESP, Stillwater, OK 74078 USA. Texas A&M Univ, Off Grad Studies, College Stn, TX 77843 USA. Texas A&M Univ, Dept Geol, College Stn, TX 77843 USA. RP Marks, SK (reprint author), Oklahoma State Univ, Dept Acad Affairs, Stillwater, OK 74078 USA. NR 30 TC 2 Z9 2 U1 1 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0169-555X J9 GEOMORPHOLOGY JI Geomorphology PD OCT 1 PY 2002 VL 47 IS 2-4 BP 261 EP 273 AR PII S0169-555X(02)00088-0 DI 10.1016/S0169-555X(02)00088-0 PG 13 WC Geography, Physical; Geosciences, Multidisciplinary SC Physical Geography; Geology GA 596LW UT WOS:000178167200012 ER PT J AU Sabaka, TJ Olsen, N Langel, RA AF Sabaka, TJ Olsen, N Langel, RA TI A comprehensive model of the quiet-time, near-Earth magnetic field: phase 3 SO GEOPHYSICAL JOURNAL INTERNATIONAL LA English DT Article DE Earth's magnetic field; electromagnetic induction; geomagnetic variation; ionosphere; lithosphere; magnetosphere ID SPHERICAL HARMONIC-ANALYSIS; GEOMAGNETIC-FIELD; MAGSAT DATA; ANOMALY MAPS; EQUATORIAL ELECTROJET; CURRENT SYSTEM; GLOBAL VECTOR; LARGE-SCALE; SPECTRUM; CORE AB The near-Earth magnetic field is caused by sources in the Earth's core, ionosphere, magnetosphere, lithosphere and from coupling currents between the ionosphere and the magnetosphere, and between hemispheres. Traditionally, the main field (low degree internal field) and magnetospheric field have been modelled simultaneously, with fields from other sources being modelled separately. Such a scheme, however, can introduce spurious features, especially when the spatial and temporal scales of the fields overlap. A new model, designated CM3 (Comprehensive Model: phase 3), is the third in a series of efforts to coestimate fields from all of these sources. This model has been derived from quiet-time Magsat and POGO satellite and observatory hourly means measurements for the period 1960-1985. It represents a significant advance in the treatment of the aforementioned field sources over previous attempts, and includes an accounting for main field influences on the magnetosphere, main field and solar activity influences on the ionosphere, seasonal influences on the coupling currents, a priori characterization of the influence of the ionosphere and the magnetosphere on Earth-induced fields, and an explicit parametrization and estimation of the lithospheric field. The result is a model that describes well the 591 432 data with 16 594 parameters, implying a data-to-parameter ratio of 36, which is larger than several popular field models. C1 Raytheon ITSS, Lanham, MD 20706 USA. Danish Space Res Inst, DK-2100 Copenhagen O, Denmark. NASA, Goddard Space Flight Ctr, Geodynam Branch, Greenbelt, MD 20771 USA. RP Sabaka, TJ (reprint author), Raytheon ITSS, Lanham, MD 20706 USA. RI Olsen, Nils/H-1822-2011; Sabaka, Terence/D-5618-2012 OI Olsen, Nils/0000-0003-1132-6113; NR 79 TC 102 Z9 120 U1 1 U2 9 PU BLACKWELL PUBLISHING LTD PI OXFORD PA 9600 GARSINGTON RD, OXFORD OX4 2DG, OXON, ENGLAND SN 0956-540X J9 GEOPHYS J INT JI Geophys. J. Int. PD OCT PY 2002 VL 151 IS 1 BP 32 EP 68 DI 10.1046/j.1365-246X.2002.01774.x PG 37 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 599RA UT WOS:000178347900003 ER PT J AU Farrell, WM Desch, MD Kaiser, ML Goetz, K AF Farrell, WM Desch, MD Kaiser, ML Goetz, K TI The dominance of electron plasma waves near a reconnection X-line region SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID MAGNETIC-FIELD RECONNECTION; GEOTAIL OBSERVATIONS; WIND SPACECRAFT; BOUNDARY-LAYER; SOLITARY WAVES; MAGNETOPAUSE; MAGNETOSPHERE; MAGNETOTAIL; SHEET AB [1] As previously reported by Oieroset et al. [2000], the Wind spacecraft made a fortuitous near-encounter in April 1999 with an active X-line reconnection region in the geomagnetic tail. The plasma flow signatures included two reversals of bulk flow velocity from earthward to tailward, and then tailward to earthward. We report here on the associated plasma wave observations made concurrently with the near-encounter with the X-line. Specifically, we find that emissions at the local upper hybrid frequency intensify greatly for short periods, with amplitudes exceeding 40 mV/m detected in the region. We discuss the upper hybrid bursts' possible importance in the electron diffusion region. C1 NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. Univ Minnesota, Sch Phys & Astron, Minneapolis, MN 55455 USA. RP Farrell, WM (reprint author), NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Code 695, Greenbelt, MD 20771 USA. RI Farrell, William/I-4865-2013 NR 20 TC 44 Z9 46 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 OCT 1 PY 2002 VL 29 IS 19 AR 1902 DI 10.1029/2002GL014662 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 638ZQ UT WOS:000180603500008 ER PT J AU Hoge, FE Lyon, PE AF Hoge, FE Lyon, PE TI Satellite observation of Chromophoric Dissolved Organic Matter (CDOM) variability in the wake of hurricanes and typhoons SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID INHERENT OPTICAL-PROPERTIES; OCEANIC RADIANCE MODEL; ABSORPTION-COEFFICIENT; MATRIX-INVERSION; RETRIEVAL; SEA; SEAWATER; GILBERT; DOC AB [1] Satellite observation of Chromophoric Dissolved Organic Matter (CDOM) absorption coefficient variability in the wake of numerous hurricanes and typhoons is reported here for the first time. Storm-induced vertically-mixed CDOM from deeper depths has a higher absorption coefficient than the photochemically degraded CDOM within the undisturbed pre-storm upper mixed layer. Principal findings are: (1) Little variability is observed prior to storm encounter at which time the CDOM-defined wake rapidly develops a notable right side asymmetry. (2) The more robust right-side CDOM absorption coefficient elevation is visible up to similar to30days depending on storm intensity. In a way that is similar to existing sea surface temperature imagery applications, the techniques in this paper are proposed as a complementary new research tool for the study of atmosphere-ocean interactions. C1 NASA, Goddard Space Flight Ctr, Wallops Flight Facil, Wallops Isl, VA 23337 USA. EG&G Inc, Goddard Space Flight Ctr, Wallops Flight Facil, Wallops Isl, VA 23337 USA. RP Hoge, FE (reprint author), NASA, Goddard Space Flight Ctr, Wallops Flight Facil, Wallops Isl, VA 23337 USA. NR 23 TC 22 Z9 22 U1 2 U2 8 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD OCT 1 PY 2002 VL 29 IS 19 AR 1908 DI 10.1029/2002GL015114 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 638ZQ UT WOS:000180603500014 ER PT J AU Kaufman, YJ Martins, JV Remer, LA Schoeberl, MR Yamasoe, MA AF Kaufman, YJ Martins, JV Remer, LA Schoeberl, MR Yamasoe, MA TI Satellite retrieval of aerosol absorption over the oceans using sunglint SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID BLACK CARBON; SUNLIGHT; CLIMATE; DUST AB [1] Aerosol absorption of sunlight, in particular by black carbon - soot and dark organic material produced from incomplete combustion of fossil fuel and from vegetation fires, is emerging as a key component of climate forcing. However, global characterization of black carbon emissions, distribution and absorption of sunlight cannot be determined within a factor of 5. Here we propose that the oceanic sunglint can be used as a bright background against which aerosol absorption can be measured from space. The method can map global ocean glint every 4-10 days and determine the distribution of aerosol absorption optical thickness with an error of +/-25% for aerosol optical thickness of 0.2 to 0.4. 18% of the ocean observations are for this range of optical thicknesses. The monthly average aerosol absorption is estimated to have an error of +/-12% and uncertainty in the single scattering albedo of +/-0.02. We outline a satellite design to perform the measurements. C1 NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. Univ Maryland, NASA, GSFC, Baltimore, MD 21201 USA. RP Kaufman, YJ (reprint author), NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. RI Yamasoe, Marcia/L-3667-2013; MARTINEZ-LOZANO, JOSE ANTONIO/B-6986-2015 OI Yamasoe, Marcia/0000-0003-3066-9146; MARTINEZ-LOZANO, JOSE ANTONIO/0000-0002-5158-5112 NR 18 TC 38 Z9 40 U1 2 U2 11 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD OCT 1 PY 2002 VL 29 IS 19 AR 1928 DI 10.1029/2002GL015403 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 638ZQ UT WOS:000180603500034 ER PT J AU Otterman, J Angell, JK Ardizzone, J Atlas, R Schubert, S Starr, D Wu, ML AF Otterman, J Angell, JK Ardizzone, J Atlas, R Schubert, S Starr, D Wu, ML TI North-Atlantic surface winds examined as the source of winter warming in Europe SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article DE sources of warm advection; maritime-air advection into Europe; changes in North Atlantic surface winds; climate trends ID TROPOSPHERIC TEMPERATURE; TRENDS AB [1] Trajectories traced backward from western Europe point to the warm southwestern North Atlantic as the source region of the warm maritime air brought into Europe by low-level southwesterlies. Over the eastern North Atlantic, patterns of ocean-surface winds in late winter changed during the second half of the 20th century, and the southwesterly direction became even more predominant. In January-to-March, the strength of southwesterlies in this region and in source region increased significantly in the years 1948-1995, and is likely to account for a large part of the observed warming in Europe during this period. For 1996-2001, however, this trend in southwesterlies appears broken, consistent with a downturn of the winter warming reported from central Europe after 1995. Monthly indexes of North Atlantic Oscillation, NAO, show a similar pattern, rising till 1995 and a downturn for the 1996-2002 winters and early spring, indicating that this climate oscillation is associated with the NAO. C1 NASA, Goddard Space Flight Ctr, Land Atmosphere Ocean Res Data Assimilat Off, Greenbelt, MD 20771 USA. NOAA, Silver Spring, MD USA. NASA, Goddard Space Flight Ctr, Sci Applicat Int Corp, Greenbelt, MD 20771 USA. RP Otterman, J (reprint author), NASA, Goddard Space Flight Ctr, Land Atmosphere Ocean Res Data Assimilat Off, Code 910-3, Greenbelt, MD 20771 USA. RI Atlas, Robert/A-5963-2011 OI Atlas, Robert/0000-0002-0706-3560 NR 20 TC 4 Z9 4 U1 1 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD OCT 1 PY 2002 VL 29 IS 19 AR 1912 DI 10.1029/2002GL015256 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 638ZQ UT WOS:000180603500018 ER PT J AU Weigel, RS Vassiliadis, D Klimas, AJ AF Weigel, RS Vassiliadis, D Klimas, AJ TI Coupling of the solar wind to temporal fluctuations in ground magnetic fields SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID GEOMAGNETICALLY INDUCED CURRENTS; COMPLEX-IMAGE METHOD; AURORAL ELECTROJET; NETWORK; POWER; DISTURBANCES; PREDICTION; VELOCITY; SURFACE; SYSTEMS AB [1] A study of the coupling of the solar wind to temporal fluctuations in high-latitude ground magnetic fields is presented. The fluctuation measure considered is the absolute value of the north-south horizontal field time derivative (\dB(x)/dt\) averaged over a 30-minute interval. The fluctuation level is predicted using a nonlinear mapping of solar wind plasma and field measurements. The predictability of ground magnetic field fluctuations is shown to depend on both local time and latitude. For lower polar cap magnetometer locations, the coupling is highest at the local times that have the highest average fluctuation level and lowest at the local times that have the lowest average fluctuation level. The highest level of coupling is at auroral-zone latitudes in the post-midnight sector. The relative influence of different solar wind inputs is shown to be highly dependent on spatial location. C1 NASA, Goddard Space Flight Ctr, NRC, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, USRA, Greenbelt, MD 20771 USA. RP Weigel, RS (reprint author), NASA, Goddard Space Flight Ctr, NRC, Greenbelt, MD 20771 USA. NR 21 TC 19 Z9 19 U1 1 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD OCT 1 PY 2002 VL 29 IS 19 AR 1915 DI 10.1029/2002GL014740 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 638ZQ UT WOS:000180603500021 ER PT J AU Yuan, JC Miller, RL AF Yuan, JC Miller, RL TI Seasonal variation in precipitation patterns to the global ocean: An analysis of the GPCP version 2 data set SO GLOBAL BIOGEOCHEMICAL CYCLES LA English DT Article DE global precipitation; seasonal variation; latitudinal variation; hydrological cycle; global water cycle ID CENTRAL ATLANTIC-OCEAN; HYDROGEN-PEROXIDE; RAINWATER; RAIN; VARIABILITY; SOUTH AB [1] Precipitation affects the thermohaline circulation, chemical mass balance, and primary productivity of surface ocean waters. An analysis of temporal and spatial variation of oceanic precipitation was conducted on the Global Precipitation Climatology Project (GPCP) version 2 data set, a monthly 2.5degrees x 2.5degrees latitude-longitude gridded data set for the period 1979 to 1999. While the precipitation patterns observed are generally similar to those reported in previous climatologies, new features and greater detail of global precipitation were revealed from our analysis of the GPCP data set. High precipitation was observed in the intertropical convergence zone (ITCZ), the South Pacific convergence zone (SPCZ), and the storm tracks in the North Pacific and Atlantic Oceans. Low precipitation was observed in the Polar regions and in the subtropics of the East Pacific, East Atlantic, and the Southeast and Northwest Indian Ocean. The spatial coverage of these high and low precipitation regions changed through the year. A strong seasonal cycle of precipitation was observed for the Northern and the Southern Hemispheres. The area-weighted mean precipitation increased from a minimum of similar to2mm d(-1) in February to a maximum of similar to5 mm d(-1) in August in the Northern Hemisphere and from a minimum of similar to2.5 mm d(-1) in September to a maximum of similar to3.5 mm d(-1) in March in the Southern Hemisphere. Similar seasonal cycles of precipitation were observed for each ocean basin. Global precipitation also varied significantly with both latitude and longitude, with a latitudinal maximum at 56degreesS, 39degreesS, 4degreesS, 6degreesN, 39degreesN, and 56degreesN, and a longitudinal maximum over each ocean. The seasonal varying precipitation patterns are a foundation for evaluating the effect of wet deposition on ocean circulation, flux of chemical species, and its effect on marine ecosystems. C1 NASA, Earth Sci Applicat Directorate, Stennis Space Ctr, Stennis Space Ctr, MS 39529 USA. RP Yuan, JC (reprint author), NASA, Earth Sci Applicat Directorate, Stennis Space Ctr, Bldg 1100,Code MA00, Stennis Space Ctr, MS 39529 USA. NR 36 TC 8 Z9 8 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0886-6236 J9 GLOBAL BIOGEOCHEM CY JI Glob. Biogeochem. Cycle PD OCT-NOV PY 2002 VL 16 IS 4 AR 1103 DI 10.1029/2001GB001458 PG 10 WC Environmental Sciences; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Geology; Meteorology & Atmospheric Sciences GA 643RK UT WOS:000180874100050 ER PT J AU Rosenzweig, C Tubiello, FN Goldberg, R Mills, E Bloomfield, J AF Rosenzweig, C Tubiello, FN Goldberg, R Mills, E Bloomfield, J TI Increased crop damage in the US from excess precipitation under climate change SO GLOBAL ENVIRONMENTAL CHANGE-HUMAN AND POLICY DIMENSIONS LA English DT Article DE agriculture; maize production; climate change; extreme events; precipitation; crop damage; insurance ID MAIZE AB Recent flooding and heavy precipitation events in the US and worldwide have caused great damage to crop production. If the frequency of these weather extremes were to increase in the near future, as recent trends for the US indicate and as projected by global climate models (e.g., US National Assessment, Overview Report, 2001, The Potential Consequences of Climate Variability and Change, National Assesment Synthesis Team, US Global Change Research Program, Washington, DC; Houghton et al., 2001, IPCC Climate Change 2001: The Scientific Basis, Third Assessment Report of the Intergovernmental Panel on Climate Change, Cambridge University Press, Cambridge, 335pp.), the cost of crop losses in the coming decades could rise dramatically. Yet current assessments of the impacts of climate change on agriculture have not quantified the negative effects on crop production from increased heavy precipitation and flooding (Impacts of climate change and variability on agriculture, in: US National Assessment Foundation Document, 2001. National Assessment Synthesis Team, US Global Change Research Program, Washington DC.). In this work, we modify a dynamic crop model in order to simulate one important effect of heavy precipitation on crop growth, plant damage from excess soil moisture. We compute that US corn production losses due to this factor, already significant under current climate, may double during the next thirty years, causing additional damages totaling an estimated $3 billion per year. These costs may either be borne directly by those impacted or transferred to private or governmental insurance and disaster relief programs. (C) 2002 Elsevier Science Ltd. All rights reserved. C1 Columbia Univ, GISS, New York, NY 10025 USA. NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA. Environm Def, Boston, MA 02108 USA. RP Tubiello, FN (reprint author), Columbia Univ, GISS, 2880 Broadway, New York, NY 10025 USA. NR 24 TC 143 Z9 150 U1 9 U2 65 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0959-3780 J9 GLOBAL ENVIRON CHANG JI Glob. Environ. Change-Human Policy Dimens. PD OCT PY 2002 VL 12 IS 3 BP 197 EP 202 AR PII S0959-3780(02)00008-0 DI 10.1016/S0959-3780(02)00008-0 PG 6 WC Environmental Sciences; Environmental Studies; Geography SC Environmental Sciences & Ecology; Geography GA 612KX UT WOS:000179075400005 ER PT J AU Shkuratov, Y Ovcharenko, A Zubko, E Miloslavskaya, O Muinonen, K Piironen, J Nelson, R Smythe, W Rosenbush, V Helfenstein, P AF Shkuratov, Y Ovcharenko, A Zubko, E Miloslavskaya, O Muinonen, K Piironen, J Nelson, R Smythe, W Rosenbush, V Helfenstein, P TI The opposition effect and negative polarization of structural analogs for planetary regoliths SO ICARUS LA English DT Article DE regolith; polarimetry; photometry; radiative transfer ID BIDIRECTIONAL REFLECTANCE SPECTROSCOPY; COHERENT BACKSCATTER; GALILEAN SATELLITES; ATMOSPHERELESS BODIES; OPTICAL POLARIMETRY; PHASE CURVES; ASTEROIDS; SCATTERING; PARTICLES; SURFACES AB To better understand the negative polarization and brightness opposition effects observed on airless celestial bodies, we carried out simultaneous photometric and polarimetric measurements of laboratory samples that simulate the structure of planetary regoliths. Computer modeling of shadow-hiding and coherent backscatter in regolith-like media are also presented. The laboratory investigations were carried out with a photometer/polarimeter at phase angles covering 0.2degrees-4degrees and wavelengths of 0.63 and 0.45 mum. We studied samples that characterize a variety of microscopic structures and albedos. A particle-size dependence of the negative branch of polarization for powdered dielectric surfaces was found. Colored samples such as a powder Fe2O3 exhibit a very prominent wavelength dependence of the photometric and polarimetric opposition phenomena. Metallic powders usually exhibit a wide branch of the negative polarization independent of the size of particles. For fine dielectric powders, both opposition phenomena become more prominent when the samples were compressed. Our computer modeling based on ray tracing in particulate media shows that shadow-hiding affects the negative polarization only in combination with the coherent backscatter enhancement. Modeling reveals that scattering orders higher than second contribute to negative polarization even in dark particulate surfaces. Our model qualitatively reproduces the effects of varying sample-compression that we observed in the laboratory. Our experimental and computer modeling studies mutually confirm that the degree of polarization for highly reflective dielectric surfaces depends not only on phase angle but also on surface tilt. Even at exactly zero phase the degree of polarization for tilted surfaces can be nonzero. A tilt of the surface normal to the scattering plane gives a parallel shift of the negative polarization branch to large values of \P\. The tilt in the perpendicular plane gives the same shift in the direction of positive polarization. At exactly zero phase angle, a celestial body of irregular shape can exhibit nonzero polarization even in integral polarimetric observations. (C) 2002 Elsevier Science (USA). C1 Kharkov Astron Observ, UA-61022 Kharkov, Ukraine. NASU, Inst Low Temp Phys & Engn, UA-61103 Kharkov, Ukraine. Osserv Astron Torino, I-10025 Pino Torinese, Italy. Univ Helsinki, Helsinki Astron Observ, FIN-00014 Helsinki, Finland. Jet Prop Lab, Pasadena, CA 91101 USA. NASU, Main Astron Observ, UA-03680 Kiev, Ukraine. Cornell Univ, Ctr Radiophys & Space Res, Ithaca, NY 14853 USA. RP Kharkov Astron Observ, Sumskaya St 35, UA-61022 Kharkov, Ukraine. EM helfenstein@cuspif.astro.cornell.edu NR 83 TC 117 Z9 118 U1 0 U2 3 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 EI 1090-2643 J9 ICARUS JI Icarus PD OCT PY 2002 VL 159 IS 2 BP 396 EP 416 DI 10.1006/icar.2002.6923 PG 21 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 601JE UT WOS:000178442000013 ER PT J AU Chesley, SR Chodas, PW Milani, A Valsecchi, GB Yeomans, DK AF Chesley, SR Chodas, PW Milani, A Valsecchi, GB Yeomans, DK TI Quantifying the risk posed by potential Earth impacts SO ICARUS LA English DT Article DE asteroids; comets ID SPACECRAFT; EROS; DISCOVERY; ASTEROIDS; HAZARD; FLYBY; MASS AB Predictions of future potential Earth impacts by near-Earth objects (NEOs) have become commonplace in recent years, and the rate of these detections is likely to accelerate as asteroid survey efforts continue to mature. In order to conveniently compare and categorize the numerous potential impact solutions being discovered we propose a new hazard scale that will describe the risk posed by a particular potential impact in both absolute and relative terms. To this end, we measure each event in two ways, first without any consideration of the event's time proximity or its significance relative to the so-called background threat, and then in the context of the expected risk from other objects over the intervening years until the impact. This approach is designed principally to facilitate communication among astronomers, and it is not intended for public communication of impact risks. The scale characterizes impacts across all impact energies, probabilities and dates, and it is useful, in particular, when dealing with those cases which fall below the threshold of public interest. The scale also reflects the urgency of the situation in a natural way and thus can guide specialists in assessing the computational and observational effort appropriate for a given situation. In this paper we describe the metrics introduced, and we give numerous examples of their application. This enables us to establish in rough terms the levels at which events become interesting to various parties. (C) 2002 Elsevier Science (USA). C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. Univ Pisa, Dipartimento Matemat, I-56100 Pisa, Italy. CNR, IASF, Rome, Italy. RP Chesley, SR (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91125 USA. OI Valsecchi, Giovanni/0000-0002-2915-1465 NR 25 TC 61 Z9 62 U1 5 U2 7 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD OCT PY 2002 VL 159 IS 2 BP 423 EP 432 DI 10.1006/icar.2002.6910 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 601JE UT WOS:000178442000015 ER PT J AU Dunham, DW Farquhar, RW McAdams, JV Holdridge, M Nelson, R Whittenburg, K Antreasian, P Chesley, S Helfrich, C Owen, WM Williams, B Veverka, J Harch, A AF Dunham, DW Farquhar, RW McAdams, JV Holdridge, M Nelson, R Whittenburg, K Antreasian, P Chesley, S Helfrich, C Owen, WM Williams, B Veverka, J Harch, A TI Implementation of the first asteroid landing SO ICARUS LA English DT Article DE asteroids; Eros; surface; asteroids; orbits ID NEAR-SHOEMAKER SPACECRAFT; EROS; 433-EROS; MISSION AB Spacecraft have successfully landed on the Moon, Venus, and Mars, and have penetrated the atmosphere of Jupiter. On 2001 February 12, the Near-Earth Asteroid Rendezvous (NEAR) Shoemaker spacecraft landed on the surface of the asteroid (433) Eros after a year of observations in orbit about the asteroid. NEAR Shoemaker was not designed to land on an asteroid, complicating the design of operations needed to accomplish this feat. However, the NEAR Shoemaker team wanted to attempt a landing after the year of orbital operations that consumed most of the remaining spacecraft fuel, operations funding, and planned Deep Space Network tracking. This would be a fitting end to the mission, and it would be possible to obtain images at much greater resolution during the descent than could be obtained from orbit. The operations were more successful than the NEAR Shoemaker team had hoped, obtaining 70 high-resolution images during the descent and two weeks of gamma-ray spectrometer data from the surface after the successful soft landing. (C) 2002 Elsevier Science (USA). C1 Johns Hopkins Univ, Appl Phys Lab, Laurel, MD 20723 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Cornell Univ, Dept Astron, Ithaca, NY 14853 USA. RP Dunham, DW (reprint author), Johns Hopkins Univ, Appl Phys Lab, 11100 Johns Hopkins Rd, Laurel, MD 20723 USA. NR 19 TC 26 Z9 28 U1 0 U2 3 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD OCT PY 2002 VL 159 IS 2 BP 433 EP 438 DI 10.1006/icar.2002.6911 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 601JE UT WOS:000178442000016 ER PT J AU Lebonnois, S Bakes, ELO McKay, CP AF Lebonnois, S Bakes, ELO McKay, CP TI Transition from gaseous compounds to aerosols in Titan's atmosphere SO ICARUS LA English DT Article DE Titan; photochemistry; organic chemistry; atmospheric, composition ID VOYAGER INFRARED OBSERVATIONS; HYDROGEN-CYANIDE POLYMERS; OPTICAL-PROPERTIES; ORGANIC-CHEMISTRY; RATE COEFFICIENTS; LOW-TEMPERATURE; MODEL; ACETYLENE; CYANOACETYLENE; PHOTOLYSIS AB We investigate the chemical transition of simple molecules like C2H2 and HCN into aerosol particles in the context of Titan's atmosphere. Experiments that synthesize analogs (tholins) for these aerosols can help illuminate and constrain these polymerization mechanisms. Using information available from these experiments, we suggest chemical pathways that can link simple molecules to macromolecules, which will be the precursors to aerosol particles: polymers of acetylene and cyanoacetylene, polycyclic aromatics, polymers of HCN and other nitriles, and polyynes. Although our goal here is not to build a detailed kinetic model for this transition, we propose parameterizations to estimate the production rates of these macromolecules, their C/N and C/H ratios, and the loss of parent molecules (C2H2, HCN, HC3N and other nitriles, and C6H6) from the gas phase to the haze. We use a onedimensional photochemical model of Titan's atmosphere to estimate the formation rate of precursor macromolecules. We find a production zone slightly lower than 200 km altitude with a total production rate of 4 x 10(-14) g cm(-2) s(-1) and a C/N similar or equal to 4. These results are compared with experimental data, and to microphysical model requirements. The Cassini/Huygens mission will bring a detailed picture of the haze distribution and properties, which will be a great challenge for our understanding of these chemical processes. (C) 2002 Elsevier Science (USA). C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Lebonnois, S (reprint author), NASA, Ames Res Ctr, MS 245-3, Moffett Field, CA 94035 USA. OI LEBONNOIS, SEBASTIEN/0000-0002-2390-8164 NR 42 TC 76 Z9 76 U1 0 U2 14 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD OCT PY 2002 VL 159 IS 2 BP 505 EP 517 DI 10.1006/icar.2002.6943 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 601JE UT WOS:000178442000021 ER PT J AU Kimura, H Mann, I Biesecker, DA Jessberger, EK AF Kimura, H Mann, I Biesecker, DA Jessberger, EK TI Dust grains in the comae and tails of sungrazing comets: Modeling of their mineralogical and morphological properties SO ICARUS LA English DT Review DE comets; composition; interplanetary dust; meteoroids; mineralogy ID INTERSTELLAR SILICATE MINERALOGY; RADIATION PRESSURE FORCES; O1 HALE-BOPP; INTERPLANETARY DUST; OPTICAL-PROPERTIES; LIGHT-SCATTERING; SOLAR NEBULA; HALLEY DUST; EVAPORATION KINETICS; AGGREGATE PARTICLES AB Observations of sungrazing comets, all of which belong to the Kreutz family, provide the opportunity of studying the properties of dust in the comae and tails of the comets. On the basis of available information on cometary and interplanetary dust as well as observations of dust in the tails of sungrazers, we model dust in sungrazing comets as fluffy silicate aggregates of submicrometer sizes. To better interpret observational data, we numerically calculate the solar radiation pressure, the equilibrium temperature, and the sublimation and crystallization rates of silicate grains near the Sun. Our results show that the dust tails contain aggregates of submicrometer crystal grains, but not amorphous grains, since amorphous silicates mostly crystallize after release from the comets. The peak in the lightcurves of the dust comae observed either at 11.2 or 12.3 solar radii (R(circle dot))) seems to result from sublimation of fluffy aggregates consisting of crystalline or amorphous olivines, respectively. We attribute an additional enhancement in the lightcurves inside 7 R(circle dot) to increasing out-flow of crystalline and amorphous pyroxenes composed fluffy aggregates. According to our model, the observed lightcurves indicate a high abundance of olivine and a low abundance of pyroxene in the comets, which may bear implications about the dynamical and thermal history of the sungrazers and their progenitor. (C) 2002 Elsevier Science (USA). C1 Univ Munster, Inst Planetol, D-48149 Munster, Germany. European Space Agcy, Estec, Solar Syst Div, NL-2200 AG Noordwijk, Netherlands. Univ Munster, Inst Planetol, D-48149 Munster, Germany. NASA, Goddard Space Flight Ctr, Commun Analyt Corp L3, Greenbelt, MD 20771 USA. RP Kimura, H (reprint author), Univ Munster, Inst Planetol, Wilhelm Klemm Str 10, D-48149 Munster, Germany. EM kimura@uni-muenster.de NR 109 TC 50 Z9 50 U1 0 U2 1 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD OCT PY 2002 VL 159 IS 2 BP 529 EP 541 DI 10.1006/icar.2002.6940 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 601JE UT WOS:000178442000023 ER PT J AU Geballe, TR Ore, CMD Cruikshank, DP Owen, TC AF Geballe, TR Ore, CMD Cruikshank, DP Owen, TC TI The 1.95-2.50 mu m spectrum of J6 Himalia SO ICARUS LA English DT Article DE ices; satellites of Jupiter; spectroscopy; surfaces, satellite ID NEAR-INFRARED SPECTROSCOPY; SOLAR-SYSTEM; WATER ICE; ASTEROIDS; SATELLITES AB The reflectance spectrum of Jupiter's sixth satellite, Himalia, is featureless in the wavelength region 1.95-2.50 mum as seen at a spectral resolution of 0.005 mum, with no absorptions deeper than a few percent. From model calculations we establish an upper limit of 10% by weight of H2O (30-mum grains) mixed intimately in the soil of Himalia, or alternatively 0.3% of the surface covered by exposures of H2O ice spatially segregated from the darker soil. For CH4 and CO2 ices the upper limits in spatially segregated models are both 0.3%. (C) 2002 Elsevier Science (USA). C1 Gemini Observ, Hilo, HI 96720 USA. SETI Inst, Moffett Field, CA 94035 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Inst Astron, Honolulu, HI 96822 USA. RP Geballe, TR (reprint author), Gemini Observ, 670 N Aohoku Pl, Hilo, HI 96720 USA. NR 20 TC 6 Z9 6 U1 0 U2 0 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 0019-1035 J9 ICARUS JI Icarus PD OCT PY 2002 VL 159 IS 2 BP 542 EP 544 DI 10.1006/icar.2002.6941 PG 3 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 601JE UT WOS:000178442000024 ER PT J AU Burton, WH Farrar, JS Steimle, F Conlin, B AF Burton, WH Farrar, JS Steimle, F Conlin, B TI Assessment of out-of-kind mitigation success of an artificial reef deployed in Delaware Bay, USA SO ICES JOURNAL OF MARINE SCIENCE LA English DT Article; Proceedings Paper CT 7th International Conference on Artificial Reefs and related Aquatic Habitats CY OCT 07-11, 1999 CL SAN REMO, ITALY SP ICES, Italian Soc Marine Biol, European Artificial Reef Res Network, Sanremo Congressi Turismo, Univ Geona, Phillips Petr, European Commiss, US Natl Marine Fisheries Serv DE benthic secondary production epifauna; estuarine artificial reef; mitigation AB An out-of-kind, off-site mitigation reef was constructed in 1989 to replace an oligohaline tidal marsh and subtidal mudflat of the upper Delaware Estuary that had been filled in 1985 to create the Wilmington Harbor South Dredged Material Disposal Area. Habitat loss consisted of 57.4 ha of subtidal, soft-bottom habitat. The mitigation reef (0.651 ha of surface area) consisted of 16 prefabricated concrete reef structures, arranged in four clusters of four units each, near Brown's Shoal in Delaware Bay. We estimated benthic secondary production of the two sites using published production: biomass ratios (P:B) as a tool for conducting comparisons of benthic epifaunal communities. Results indicate that the artificial reef provides enhanced benthic secondary production per unit area (2000-12000 kcal yr(-1)) over the lost habitat (177 kcal yr(-1)), but that total production (3 and 77 million kcal yr(-1)) does not equal what has been lost (100 million kcal/yr). The construction of this reef, while not completely effective in its intended mitigation, provides a benchmark by which to design and judge future mitigation efforts. (C) 2002 International Council for the Exploration of the Sea. Published by Elsevier Science Ltd. All rights reserved. C1 Versar Inc, Columbia, MD 21045 USA. Natl Marine Fisheries Serv, Highlands, NJ 07732 USA. US Dept Army, Corps Engineers, Philadelphia, PA 19107 USA. RP Burton, WH (reprint author), Versar Inc, 9200 Rumsey Rd, Columbia, MD 21045 USA. NR 20 TC 5 Z9 5 U1 2 U2 6 PU ACADEMIC PRESS LTD ELSEVIER SCIENCE LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 1054-3139 J9 ICES J MAR SCI JI ICES J. Mar. Sci. PD OCT PY 2002 VL 59 SU S BP S106 EP S110 DI 10.1006/jmsc.2002.1269 PG 5 WC Fisheries; Marine & Freshwater Biology; Oceanography SC Fisheries; Marine & Freshwater Biology; Oceanography GA 615KC UT WOS:000179243500017 ER PT J AU Helvey, M AF Helvey, M TI Are southern California oil and gas platforms essential fish habitat? SO ICES JOURNAL OF MARINE SCIENCE LA English DT Article; Proceedings Paper CT 7th International Conference on Artificial Reefs and Related Aquatic Habitats CY OCT 07-11, 1999 CL SAN REMO, ITALY SP ICES, Italian Soc Marine Biol, European Artificial Reef Res Network, Sanremo Congressi Turismo, Univ Geona, Phillips Petr, European Commiss, US Natl Marine Fisheries Serv DE artificial reefs; essential fish habitat; groundfish; Magnuson-Stevens Act; oil platforms ID SANTA-BARBARA CHANNEL; FISHERIES MANAGEMENT; MARINE RESERVES; REEF FISHES; ASSEMBLAGES; BIOMASS; BIGHT AB US federal agencies must consult with the National Marine Fisheries Service on actions that may adversely affect "essential fish habitat" (EFH). This EFH mandate coincides with recent discussions on proposed decommissioning of oil and gas platforms in southern California. While many species falling under the Pacific Groundfish Fishery Management Plan (e.g. rockfish, genus Sebastes) inhabit platforms, available information is insufficient for determining whether the structures are necessary to support a sustainable fishery or contribute to a healthy ecosystem, the two basic tenets of EFH. The occurrence of juvenile and large adult rockfish at some platforms suggests that they may support important ecological functions. Because rockfish show long-term population declines, further evaluation of platform ecological structure and function is warranted and should be integrated into the environmental review process. Published by Elsevier Science Ltd on behalf of the International Council for the Exploration of the Sea. C1 Natl Marine Fisheries Serv, Habitat Conservat Div, Long Beach, CA 92610 USA. RP Natl Marine Fisheries Serv, Habitat Conservat Div, SW Region,501 W Ocean Blvd,Suite 4200, Long Beach, CA 92610 USA. EM mark.helvey@noaa.gov NR 21 TC 19 Z9 20 U1 1 U2 15 PU OXFORD UNIV PRESS PI OXFORD PA GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND SN 1054-3139 EI 1095-9289 J9 ICES J MAR SCI JI ICES J. Mar. Sci. PD OCT PY 2002 VL 59 SU S BP S266 EP S271 DI 10.1006/jmsc.2002.1226 PG 6 WC Fisheries; Marine & Freshwater Biology; Oceanography SC Fisheries; Marine & Freshwater Biology; Oceanography GA 615KC UT WOS:000179243500042 ER PT J AU Steimle, F Foster, K Kropp, R Conlin, B AF Steimle, F Foster, K Kropp, R Conlin, B TI Benthic macrofauna productivity enhancement by an artificial reef in Delaware Bay, USA SO ICES JOURNAL OF MARINE SCIENCE LA English DT Article; Proceedings Paper CT 7th International Conference on Artificial Reefs and related Aquatic Habitats CY OCT 07-11, 1999 CL SAN REMO, ITALY SP ICES, Italian Soc Marine Biol, European Artificial Reef Res Network, Sanremo Congressi Turismo, Univ Geona, Phillips Petr, European Commiss, US Natl Marine Fisheries Serv DE caloric conversions; epifauna; estuarine artificial reef; interannual variability; Mytilus edulis; taxon-specific P : B ID NEW-YORK-BIGHT; MYTILUS-EDULIS; MUSSEL BED; COMMUNITY; HABITAT; METABOLISM; MORTALITY; ESTUARY AB To understand the potential enhancement value of a habitat-loss mitigation reef in Delaware Bay, especially as a source of food for fishery resources, the secondary productivity of the reef epifauna and nearby sand infauna was estimated and compared. The mean production of natural sand infauna was estimated at between 215 and 249 kcal m(2) yr(-1), while that of the epifauna on the reef surfaces was between 3990 and 9555 kcal m(2) yr(-1). With the 36 m(2) footprint of a reef unit as a basis for comparison, the 407 m(2) of reef unit surface covering that footprint produced 1.62-3.89 X 10(6) kcal yr(-1) of epifauna compared with 7.74-8.96 X 10(3) kcal yr(-1) per footprint area for the adjacent sand infauna. There was, however, substantial annual variability in the productivity of the epifauna, based on the recruitment success of Mytilus edulis. Published by Elsevier Science Ltd on behalf of the International Council for the Exploration of the Sea. C1 Natl Marine Fisheries Serv, Sandy Hook Lab, Highlands, NJ 07732 USA. Battelle Ocean Sci, Duxbury, MA 02332 USA. US Dept Army, Corps Engineers, Philadelphia, PA 19107 USA. RP Steimle, F (reprint author), Natl Marine Fisheries Serv, Sandy Hook Lab, Highlands, NJ 07732 USA. NR 38 TC 5 Z9 5 U1 2 U2 7 PU ACADEMIC PRESS LTD ELSEVIER SCIENCE LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 1054-3139 J9 ICES J MAR SCI JI ICES J. Mar. Sci. PD OCT PY 2002 VL 59 SU S BP S100 EP S105 DI 10.1006/jmsc.2002.1268 PG 6 WC Fisheries; Marine & Freshwater Biology; Oceanography SC Fisheries; Marine & Freshwater Biology; Oceanography GA 615KC UT WOS:000179243500016 ER PT J AU Workman, I Shah, A Foster, D Hataway, B AF Workman, I Shah, A Foster, D Hataway, B TI Habitat preferences and site fidelity of juvenile red snapper (Lutjanus campechanus) SO ICES JOURNAL OF MARINE SCIENCE LA English DT Article; Proceedings Paper CT 7th International Conference on Artificial Reefs and related Aquatic Habitats CY OCT 07-11, 1999 CL SAN REMO, ITALY SP ICES, Italian Soc Marine Biol, European Artificial Reef Res Network, Sanremo Congressi Turismo, Univ Geona, Phillips Petr, European Commiss, US Natl Marine Fisheries Serv DE habitat preferences; homing instinct; juvenile red snapper; site fidelity ID GULF-OF-MEXICO; FISHERY; GROWTH AB Ten small reefs constructed of either oyster shell or polyethylene webbing and ten randomly selected open-bottom sites within a distance of 3.7 km of the reefs were used to determine juvenile red snapper [Lutjanus campechanus (Poey, 1860)] habitat preferences. The reefs were deployed at 40, 50, 70, and 90 m from a flare stack located in a gas field off the coast of Mississippi. Juvenile red snapper were observed at one of the open-bottom sites when it was first surveyed, but none during a second survey conducted 45 days later. Age-0 and age-1 fish showed a preference for the more complex study reefs, but presence of age-1 appeared to limit recruitment of age-0 to a reef. As age-1 fish started to leave the reefs, increased numbers of age-0 were observed moving onto them. However, age-0 were never observed at the 40-m reef occupied by older fish throughout the study. Distance from the flare stack also appeared to have an effect on recruitment to the reefs. Age-0 were first observed at the 50-m reefs. They appeared at the 70-m reefs a week later and at the 90-m reefs almost a month later. Age-1 fish showed a preference for the reefs located closest to the flare stack. Juvenile red snapper site fidelity was determined using fish that either were tagged and released on site or were removed from the capture site before release. Fish from the on-site release were repeatedly sighted at the capture reef over about a 2-month period. Displaced fish, as determined with tracking equipment, were able to find their way back to the capture reef from as far away as 0.43 km in about 25 min. We conclude that juvenile red snapper are not only faithful to structures, but also have homing capabilities. Published by Elsevier Science Ltd on behalf of the International Council for the Exploration of the Sea. C1 Natl Marine Fisheries Serv, Pascagoula, MS 39568 USA. Merck & Co Inc, Merck Res Labs, Rahway, NJ 07065 USA. RP Shah, A (reprint author), Natl Marine Fisheries Serv, PO Drawer 1207, Pascagoula, MS 39568 USA. NR 24 TC 20 Z9 20 U1 2 U2 6 PU ACADEMIC PRESS LTD ELSEVIER SCIENCE LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 1054-3139 J9 ICES J MAR SCI JI ICES J. Mar. Sci. PD OCT PY 2002 VL 59 SU S BP S43 EP S50 DI 10.1006/jmsc.2001.1211 PG 8 WC Fisheries; Marine & Freshwater Biology; Oceanography SC Fisheries; Marine & Freshwater Biology; Oceanography GA 615KC UT WOS:000179243500008 ER PT J AU Gunnam, KK Hughes, DC Junkins, JL Kehtarnavaz, N AF Gunnam, Kiran K. Hughes, Declan C. Junkins, John L. Kehtarnavaz, Nasser TI A Vision-Based DSP Embedded Navigation Sensor SO IEEE SENSORS JOURNAL LA English DT Article DE Active beacons; decimating filter bank; digital signal processor (DSP); frequency division multiplexing (FDM); Gaussian least squares differential correction (GLSDC); modified Rodrigues parameters (MRPs); noncontact optoelectronic sensor; positioning system; precision navigation; position sensitive diode (PSD) sensor; six-degrees-of-freedom (6DOF) estimation; spacecraft docking; synchronous demodulation; vision-based navigation (VISNAV) AB Spacecraft missions such as spacecraft docking and formation flying require high-precision relative position and attitude data. Although a global positioning system can provide this capability near the earth, deep space missions require the use of alternative technologies. One such technology is the vision-based navigation (VISNAV) sensor system developed at Texas A&M University. VISNAV comprises an electro-optical sensor combined with light sources or beacons. This patented sensor has an analog detector in the focal plane with a rise time of a few microseconds. Accuracies better than one part in 2000 of the field of view have been obtained. This paper presents a new approach involving simultaneous activation of beacons with frequency division multiplexing as part of the VISNAV sensor system. In addition, it discusses the synchronous demodulation process using digital heterodyning and decimating filter banks on a low-power fixed point digital signal processor, which improves the accuracy of the sensor measurements and the reliability of the system. This paper also presents an optimal and computationally efficient six-degree-of-freedom estimation algorithm using a new measurement model based on the attitude representation of modified Rodrigues parameters. C1 [Gunnam, Kiran K.] Texas A&M Univ, Dept Elect Engn, College Stn, TX 77840 USA. [Hughes, Declan C.] Texas A&M Univ, NASA, Commercial Space Ctr Engn, College Stn, TX 77840 USA. [Junkins, John L.] Texas A&M Univ, Dept Aerosp Engn, College Stn, TX 77840 USA. [Kehtarnavaz, Nasser] Univ Texas Dallas, Dept Elect Engn, Richardson, TX 75083 USA. RP Gunnam, KK (reprint author), Texas A&M Univ, Dept Elect Engn, College Stn, TX 77840 USA. EM kiran.k.gunnam@ieee.org; dhughes@aero.tamu.edu; junkins@tamu.edu; kehtar@utdallas.edu FU NASA Goddard Space Flight Center [NCC5-448]; Texas Instruments FX This work was supported by Grant NCC5-448 from NASA Goddard Space Flight Center to Texas Engineering Experiment Station for the research entitled Vision-Based Navigation for Spacecraft Formation Flying and partially by Texas Instruments sponsored DSP Program at Texas A&M University, College Station. The associate editor coordinating the review of this paper and approving it for publication was Dr. Eugenii Katz. NR 11 TC 32 Z9 33 U1 0 U2 9 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 1530-437X J9 IEEE SENS J JI IEEE Sens. J. PD OCT PY 2002 VL 2 IS 5 BP 428 EP 442 DI 10.1109/JSEN.2002.806212 PG 15 WC Engineering, Electrical & Electronic; Instruments & Instrumentation; Physics, Applied SC Engineering; Instruments & Instrumentation; Physics GA V23EQ UT WOS:000208326500008 ER PT J AU Wang, CC Pottie, GJ AF Wang, CC Pottie, GJ TI Variable bit allocation for FH-CDMA wireless communication systems SO IEEE TRANSACTIONS ON COMMUNICATIONS LA English DT Article DE code-division multiple access; power control; wireless LAN ID CHANNEL AB In the wireless indoor environment, the channel may vary slowly as users and the interferers may move at slow speeds. A frequency-hopped code-division multiple-access system can adapt to the different interference levels in hopping patterns and assign the slots different bit rates to increase the system capacity. We show that the maximum throughput bit-rate/channel-assignment problem is NP-hard. Several practical ad hoc bit-allocation algorithms are designed based on the insights derived from exhaustive searches. The algorithms that achieve the most, system capacity perform interference avoidance. Users concentrate their throughput in a small fraction of the slots with low interference by transmitting large signal constellations, while avoiding the channels with large interference. Simulations show that the flexibility of users to adjust their bit rates to the interference environment can significantly increase the system capacity. C1 Jet Prop Lab, Pasadena, CA 91101 USA. Univ Calif Los Angeles, Dept Elect Engn, Los Angeles, CA 90024 USA. RP Wang, CC (reprint author), ESS Technol, Irvine, CA 92612 USA. NR 17 TC 2 Z9 2 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 0090-6778 J9 IEEE T COMMUN JI IEEE Trans. Commun. PD OCT PY 2002 VL 50 IS 10 BP 1637 EP 1644 DI 10.1109/TCOMM.2002.803969 PG 8 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA 614CH UT WOS:000179170400014 ER PT J AU Li, XF Pichel, WG He, MX Wu, SY Friedman, KS Clemente-Colon, P Zhao, CF AF Li, XF Pichel, WG He, MX Wu, SY Friedman, KS Clemente-Colon, P Zhao, CF TI Observation of hurricane-generated ocean swell refraction at the Gulf Stream north wall with the RADARSAT-1 synthetic aperture radar SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article; Proceedings Paper CT International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL SYDNEY, AUSTRALIA DE Gulf Stream; refraction; surface waves; synthetic aperture radar ID WAVE REFRACTION; IMAGERY; SPECTRA; SAR; ICE AB In this study, we analyze the refraction of long oceanic waves at the Gulf Stream's north wall off the Florida coast as observed in imagery obtained from the RADARSAT-1 synthetic aperture radar (SAR) during the passage of Hurricane Bonnie on August 25, 1998. The wave spectra are derived from RADARSAT-1 SAR images from both inside and outside the Gulf Stream. From the image spectra, we can determine both the long wave's dominant wavelength and its propagation direction with 180degrees ambiguity. We find that the wavelength of hurricane-generated ocean waves can exceed 200 m. The calculated dominant wavelength from the SAR image spectra agree very well with in situ measurements made by National Oceanic and Atmospheric Administration National Data Buoy Center buoys. Since the waves mainly propagate toward the continental shelf from the open ocean, we can eliminate the wave propagation ambiguity. We also discuss the velocity-bunching mechanism. We find that in this very long wave case, the RADARSAT-1 SAR wave spectra should not be appreciably affected by the azimuth falloff, and we find that the ocean swell measurements can be considered reliable. We observe that the oceanic long waves change their propagation directions as they leave the Gulf Stream current. A wave-current interaction model is used to simulate the wave refraction at the Gulf Stream boundary. In addition, the wave shoaling effect is discussed. We find that wave refraction is the dominant mechanism at the Gulf Stream boundary for these very long ocean swells, while wave reflection is not a dominant factor. We extract 256-by-256 pixel full-resolution subimages from the SAR image on both sides of the Gulf Stream boundary, and then derive the wave spectra. The SAR-observed swell refraction angles at the Gulf Stream north wall agree reasonably well with those calculated by the wave-current interaction model. C1 NOAA, NESDIS, Camp Springs, MD 20746 USA. Ocean Univ Qingdao, Ocean Remote Sensing Inst, Qingdao 266003, Peoples R China. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP NOAA, NESDIS, Camp Springs, MD 20746 USA. RI Clemente-Colon, Pablo/F-5581-2010; Pichel, William/F-5619-2010; Li, Xiaofeng/B-6524-2008 OI Pichel, William/0000-0001-6332-0149; Li, Xiaofeng/0000-0001-7038-5119 NR 28 TC 29 Z9 29 U1 2 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 0196-2892 EI 1558-0644 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD OCT PY 2002 VL 40 IS 10 BP 2131 EP 2142 DI 10.1109/TGRS.2002.802474 PG 12 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 625CC UT WOS:000179798500004 ER PT J AU Jackson, TJ Gasiewski, AJ Oldak, A Klein, M Njoku, EG Yevgrafov, A Christiani, S Bindlish, R AF Jackson, TJ Gasiewski, AJ Oldak, A Klein, M Njoku, EG Yevgrafov, A Christiani, S Bindlish, R TI Soil moisture retrieval using the C-band polarimetric scanning radiometer during the Southern Great Plains 1999 Experiment SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article; Proceedings Paper CT International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL SYDNEY, AUSTRALIA DE advanced microwave scanning radiomete (AMSR); passive microwave; soil moisture ID MICROWAVE EMISSION AB The Advanced Microwave Scanning Radiometer (AMSR) holds promise for retrieving soil moisture in regions with low levels of vegetation. Algorithms for this purpose have been proposed, but none have been rigorously evaluated due to a lack of datasets. Accordingly, the Southern Great Plains 1999 Experiment (SGP99) was designed to provide C-band datasets for AMSR algorithm development and validation. Ground observations of soil moisture and related variables were collected in conjunction with aircraft measurements using a C-band radiometer similar to the AMSR sensor (6.92 GHz), the Polarimetric Scanning Radiometer with its C-band scanhead (PSR/C). The study region has been the focus of several previous remote sensing field experiments and contains vegetation conditions compatible with the expected capabilities of C-band for soil moisture retrieval. Flights were conducted under a Aide range of soil moisture conditions, thus providing a robust dataset for validation. A significant issue found in data processing was the removal of anthropogenic radio-frequency interference. Several approaches to estimating the parameters of a single-channel soil moisture retrieval algorithm were used. PSR/C soil moisture images show spatial and temporal patterns consistent with meteorological and soil conditions, and the dynamic range of the PSR/C observations indicates that the AMSR instrument can provide useful soil moisture information. C1 USDA ARS, ARS Hydrol & Remote Sensing Lab, Beltsville, MD 20705 USA. NOAA, Environm Technol Lab, Boulder, CO 80305 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Shure Europe GMBH, Heilbronn, Germany. Syst Sci & Applicat Inc, Lanham, MD 20706 USA. RP Jackson, TJ (reprint author), USDA ARS, ARS Hydrol & Remote Sensing Lab, Beltsville, MD 20705 USA. NR 12 TC 55 Z9 56 U1 2 U2 8 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD OCT PY 2002 VL 40 IS 10 BP 2151 EP 2161 DI 10.1109/TGRS.2002.802480 PG 11 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 625CC UT WOS:000179798500006 ER PT J AU Moghaddam, M Dungan, JL Acker, S AF Moghaddam, M Dungan, JL Acker, S TI Forest variable estimation from fusion of SAR and multispectral optical data SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article; Proceedings Paper CT International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL SYDNEY, AUSTRALIA DE forestry; geophysical inverse problems; microwave imaging; nonlinear optimization; optical imaging; scattering ID LEAF-AREA INDEX; BOREAL FOREST; BIOPHYSICAL CHARACTERISTICS; ABOVEGROUND BIOMASS; VEGETATION INDEXES; RADIATIVE-TRANSFER; RADAR; SCATTERING; OREGON; MODEL AB Radar and optical remote sensing data are used in a unified algorithm to estimate forest variables. The study site is the H. J. Andrews experimental forest in Oregon, which has significant topography and several mature and old-growth conifer stands with biomass values sometimes exceeding 1000 tons/ha. Polarimetric multifrequency Airborne Synthetic Aperture Radar (AIRSAR) back-scatter, interferometric C-band Topographic Synthetic Aperture Radar (TOPSAR) coherence, and multispectral Landsat Thematic Mapper (TM) digital numbers are used in a regression analysis that relates them to forest variable measurements on the ground. Parametric expressions are derived and used to estimate the same variables(s) at other locations from the combination of AIRSAR and TM, data. It is shown that the estimation accuracy is significantly improved when the radar and optical data are used in combination compared to estimating the same variable from a single data type alone. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Natl Pk Serv, Pacific W Reg, Seattle, WA 98104 USA. RP Moghaddam, M (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Dungan, Jennifer/G-9921-2016 OI Dungan, Jennifer/0000-0002-4863-1616 NR 39 TC 36 Z9 40 U1 2 U2 14 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD OCT PY 2002 VL 40 IS 10 BP 2176 EP 2187 DI 10.1109/TGRS.2002.804725 PG 12 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 625CC UT WOS:000179798500009 ER PT J AU Reagan, JA Wang, X Osborn, MT AF Reagan, JA Wang, X Osborn, MT TI Spaceborne lidar calibration from cirrus and molecular backscatter returns SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article; Proceedings Paper CT International Geoscience and Remote Sensing Symposium CY JUL 09-13, 2001 CL SYDNEY, AUSTRALIA DE cirrus backscatter; Lidar callibration; spaceborne Lidar ID LIGHT-SCATTERING; ICE CRYSTALS AB In order to make optimal quantitative use of multiwavelength spaceborne lidar data, it is essential that the lidar be well calibrated. Due to system gain/efficiency changes that can be expected to occur during the course of a shuffle or satellite mission, it is essential to employ a calibration approach that can be implemented on-orbit, preferably repeatable at least a few times per orbit. For wavelengths less than about 550 run, in situ calibration can be accomplished via normalization to high-altitude nearly molecular scattering regions. However, for longer wavelengths beyond about 800 nm, particularly the popular Nd: YAG fundamental wavelength at 1064 nm, the Rayleigh normalization approach becomes questionable due to both an inherently weaker signal and a stronger, variable, and somewhat unknown aerosol scattering contribution. For lidars operating at both longer and shorter wavelengths, a viable approach is to retrieve the longer wavelength calibrations ratioed to the shorter wavelength calibrations via comparisons of spectral backscatter from known/quantifiable scatterers. Cirrus clouds are good for this purpose because they occur at high altitudes with significant frequency and provide strong nearly spectrally flat backscatter. This paper presents both the molecular normalization and cirrus spectral backscatter ratio calibration approaches, including results obtained from case studies of War data collected during the LITE shuttle mission. Attention is focused on developing a simple autonomous approach applicable to satellite lidar missions such as Cloud-Aerosol Lidar Infrared Pathfinder Satellite Observations (CALIPSO) and the Geoscience Laser Altimeter System (GLAS). C1 Univ Arizona, Dept Elect & Comp Engn, Tucson, AZ 85721 USA. NASA, Langley Res Ctr, Sci Applicat Int Corp, Hampton, VA 23681 USA. RP Reagan, JA (reprint author), Univ Arizona, Dept Elect & Comp Engn, Tucson, AZ 85721 USA. NR 14 TC 35 Z9 37 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 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD OCT PY 2002 VL 40 IS 10 BP 2285 EP 2290 DI 10.1109/TGRS.2002.802464 PG 6 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 625CC UT WOS:000179798500021 ER PT J AU Giakos, GC Meehan, K Tuma, M AF Giakos, GC Meehan, K Tuma, M TI Exploitation of enhanced fluorescence via cross-coupling principles toward the design of an optical integrated thin-film sensor for nanotechnology and biomedical applications SO IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT LA English DT Article DE bioengineering applications; enhanced fluorescence; high sensitivity; nanotechnology; optical sensor; surface plasmon-surface plasmon (SP-SP) interaction ID SURFACE-PLASMON RESONANCE; MOLECULAR FLUORESCENCE; DIFFRACTION GRATINGS; SENSITIVITY; SHIFTS AB A novel fluorescence thin-film integrated sensor has been proposed that retains the beneficial selectivity characteristics typical of optical and electronic sensors, while improving the signal-to-noise ratio in a miniature geometry. The sensor can be tuned to measure a wide variety of biological species by varying its thin-film corrugation period. The optical properties of the sensor are determined, in large part, by optical cross coupling through a corrugated metal film and enhanced fluorescence. The surface plasmon to surface plasmon cross coupling was theoretically modeled and experimentally tested. Finally, prospective applications of this sensor in the key areas of nanotechnology and bioengineering are discussed. C1 Univ Akron, Olson Res Ctr, Dept Elect & Comp Engn, Imaging Devices Sensors & Intelligent Based Sens, Akron, OH 44325 USA. W Virginia Univ, Dept Comp Sci & Elect Engn, Morgantown, WV 25606 USA. NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Giakos, GC (reprint author), Univ Akron, Olson Res Ctr, Dept Elect & Comp Engn, Imaging Devices Sensors & Intelligent Based Sens, Akron, OH 44325 USA. NR 24 TC 5 Z9 6 U1 0 U2 3 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017-2394 USA SN 0018-9456 J9 IEEE T INSTRUM MEAS JI IEEE Trans. Instrum. Meas. PD OCT PY 2002 VL 51 IS 5 BP 970 EP 975 DI 10.1109/TIM.2002.806037 PG 6 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA 640WX UT WOS:000180712400015 ER PT J AU Lin, PP Jules, K AF Lin, PP Jules, K TI An intelligent system for monitoring the microgravity environment quality on-board the international space station SO IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT LA English DT Article DE adaptive pattern recognition and classification; (APRC); back propagation neural network (BPNN); learning vector quantization (LVQ); microgravity; self-organizing feature map (SOFM); source detection; system monitoring AB An intelligent system for monitoring the microgravity environment quality on-board the International Space Station is presented. The monitoring system uses a new approach combining Kohonen's self-organizing feature map, learning vector quantization, and a back propagation neural network to recognize and classify the known and unknown patterns. Finally, fuzzy logic is used to assess the level of confidence associated with each vibrating source activation detected by the system. C1 Cleveland State Univ, Dept Mech Engn, Cleveland, OH 44115 USA. NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Lin, PP (reprint author), Cleveland State Univ, Dept Mech Engn, Cleveland, OH 44115 USA. NR 7 TC 1 Z9 1 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 0018-9456 J9 IEEE T INSTRUM MEAS JI IEEE Trans. Instrum. Meas. PD OCT PY 2002 VL 51 IS 5 BP 1002 EP 1009 DI 10.1109/TIM.2002.806016 PG 8 WC Engineering, Electrical & Electronic; Instruments & Instrumentation SC Engineering; Instruments & Instrumentation GA 640WX UT WOS:000180712400021 ER PT J AU Focardi, P Neto, A McGrath, WR AF Focardi, P Neto, A McGrath, WR TI Coplanar-waveguide-based terahertz hot-electron-bolometer mixers - Improved embedding circuit description SO IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES LA English DT Article DE characteristic impedance; coplanar waveguide; CPW transitions; hot electron bolometer; leaky waves; slot antennas ID IMPEDANCE; ANTENNAS AB Series-fed coplanar-waveguide embedding circuits have been recently developed for terahertz mixers using, in particular, superconducting devices as sensors. Although these mixers show promising performance, they usually also show a considerable downward shift in the resonating frequency when compared with calculations using simplified models. This effect is basically caused by parasitics due to the extremely small details (in terms of wavelength) of the device and to the connection of the remaining circuitry (i.e., RF filter). In this paper, we present an improved equivalent-network model of such devices that agrees with measured results. We first propose a method to calculate the characteristic impedance and propagation constant of the coplanar waveguide, etched between two semi-infinite media, which connect the receiving slot antennas to the superconducting device. In the formulation, we take into account. for the first time, the radiation power leakage. We then describe the procedure to calculate the reactances due to the detailed geometry of the mixer device and circuit and we correct the input impedance, calculated with a commonly used simplified network. Finally, by comparing our results with a complete set of measured data, for seven mixers in the range between 500 GHz-3 THz, we analyze the features of our model and propose further improvements. Useful guidelines for designing terahertz mixer circuits are also given. C1 CALTECH, Jet Prop Lab, Microwave Expt Syst & Technol Sect, Pasadena, CA 91109 USA. FEL TNO, The Hague, Netherlands. RP Focardi, P (reprint author), CALTECH, Jet Prop Lab, Microwave Expt Syst & Technol Sect, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 15 TC 23 Z9 23 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 0018-9480 J9 IEEE T MICROW THEORY JI IEEE Trans. Microw. Theory Tech. PD OCT PY 2002 VL 50 IS 10 BP 2374 EP 2383 DI 10.1109/TMTT.2002.803448 PG 10 WC Engineering, Electrical & Electronic SC Engineering GA 601EF UT WOS:000178433000020 ER PT J AU Driver, DM Mateer, GG AF Driver, DM Mateer, GG TI Wake flow in adverse pressure gradient SO INTERNATIONAL JOURNAL OF HEAT AND FLUID FLOW LA English DT Article ID UPWIND DIFFERENCING SCHEME; NAVIER-STOKES EQUATIONS AB In the interest of improving the predictability of high-lift systems at maximum lift conditions, a series of fundamental experiments were conducted to study the effects of adverse pressure gradient on a wake flow. Mean and fluctuating velocities were measured with a two-component laser-Doppler velocimeter. Data were obtained for several cases of adverse pressure gradient, producing flows ranging from no reversed flow to massively reversed flow. While the turbulent Reynolds stresses increase with increasing size of the reversed flow region, the gradient of Reynolds stress (-partial derivative<(unu)over bar>/partial derivativey) does not. Computations using various turbulence models were unable to reproduce the reversed flow. (C) 2002 Elsevier Science Inc. All rights reserved. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. MCAT Inst, Los Gatos, CA 95030 USA. RP Driver, DM (reprint author), NASA, Ames Res Ctr, M-S 260-1, Moffett Field, CA 94035 USA. EM ddriver@mail.arc.nasa.gov; gmateer@worldnet.att.net NR 14 TC 5 Z9 5 U1 0 U2 0 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0142-727X J9 INT J HEAT FLUID FL JI Int. J. Heat Fluid Flow PD OCT PY 2002 VL 23 IS 5 BP 564 EP 571 AR PII S0142-727X(02)00152-2 DI 10.1016/S0142-727X(02)00152-2 PG 8 WC Thermodynamics; Engineering, Mechanical; Mechanics SC Thermodynamics; Engineering; Mechanics GA 567XL UT WOS:000176511800004 ER PT J AU Moin, P AF Moin, P TI Advances in large eddy simulation methodology for complex flows SO INTERNATIONAL JOURNAL OF HEAT AND FLUID FLOW LA English DT Article ID FINITE-DIFFERENCE SCHEMES; TURBULENT FLOWS; MODEL AB A review is provided of the recent advances in the derivation of the constitutive equations for large eddy simulation, subgrid scale modeling, wall modeling and applications of LES to turbulent combustion. The majority of the paper focuses on a review of two numerical methods for LES in complex geometry: the immersed boundary method and an unstructured mesh scheme. The latter scheme is applied to LES of a sector of a combustor of an operational gas turbine engine. (C) 2002 Published by Elsevier Science Inc. C1 Stanford Univ, Ctr Turbulence Res, Stanford, CA 94305 USA. NASA, Ames, IA USA. RP Moin, P (reprint author), Stanford Univ, Ctr Turbulence Res, Stanford, CA 94305 USA. NR 31 TC 136 Z9 147 U1 2 U2 25 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0142-727X J9 INT J HEAT FLUID FL JI Int. J. Heat Fluid Flow PD OCT PY 2002 VL 23 IS 5 BP 710 EP 720 AR PII S0142-727X(02)00167-4 DI 10.1016/S0142-727X(02)00167-4 PG 11 WC Thermodynamics; Engineering, Mechanical; Mechanics SC Thermodynamics; Engineering; Mechanics GA 567XL UT WOS:000176511800019 ER PT J AU Zhang, H Mudawar, I Hasan, MM AF Zhang, H Mudawar, I Hasan, MM TI Experimental and theoretical study of orientation effects on flow boiling CHF SO INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER LA English DT Article DE critical heat flux; flow boiling; orientation ID CRITICAL HEAT-FLUX; MECHANISM; MODEL; WALL; LONG AB The effects of orientation on flow boiling critical heat flux (CHF) were investigated using high-speed video and microphotographic techniques. Interfacial features were measured just prior to CHF and statistically analyzed. A dominant wavy vapor layer regime was observed for all relatively high-velocities and most orientations, while several other regimes were encountered at low velocities, in downflow and/or downward-facing heated wall orientations. The interfacial lift-off model was modified and used to predict the orientation effects on CHF for the dominant wavy vapor layer regime. The photographic study revealed a fairly continuous wavy vapor layer travelling along the heated wall while permitting liquid contact only in wetting fronts, located in the troughs of the interfacial waves. The waves, which were generated at an upstream location, had a tendency to preserve a curvature ratio as they propagated along the heated wall. CHF commenced when wetting fronts near the outlet were lifted off the wall. This occurred when the momentum of vapor normal to the wall exceeded the pressure force associated with interfacial curvature. The interfacial lift-off model is shown to be very effective at capturing the overall dependence of CHF on orientation. (C) 2002 Elsevier Science Ltd. All rights reserved. C1 Purdue Univ, Sch Mech Engn, Boiling & Two Phase Flow Lab, W Lafayette, IN 47907 USA. NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Mudawar, I (reprint author), Purdue Univ, Sch Mech Engn, Boiling & Two Phase Flow Lab, 1288 Mech Engn Bldg, W Lafayette, IN 47907 USA. NR 17 TC 32 Z9 34 U1 0 U2 6 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0017-9310 J9 INT J HEAT MASS TRAN JI Int. J. Heat Mass Transf. PD OCT PY 2002 VL 45 IS 22 BP 4463 EP 4477 AR PII S0017-9310(02)00152-7 DI 10.1016/S0017-9310(02)00152-7 PG 15 WC Thermodynamics; Engineering, Mechanical; Mechanics SC Thermodynamics; Engineering; Mechanics GA 586DZ UT WOS:000177570500007 ER PT J AU Turner, MS AF Turner, MS TI Making sense of the new cosmology SO INTERNATIONAL JOURNAL OF MODERN PHYSICS A LA English DT Article; Proceedings Paper CT Conference of the Michigan-Center-for-Theoretical-Physics CY MAY 21-25, 2001 CL ANN ARBOR, MI ID COLD DARK-MATTER; OBSERVATIONAL EVIDENCE; ACCELERATING UNIVERSE; CONSTANT; SUPERNOVAE; DECELERATION; ANISOTROPY; LAMBDA; MODELS AB Over the past three years we have determined the basic features of the Universe - spatially flat; accelerating; comprised of 1/3 a new form of matter, 2/3 a new form of energy, with some ordinary matter and a dash of massive neutrinos; and apparently born from a burst of rapid expansion during, which quantum noise was stretched to astrophysical size seeding cosmic structure. The New Cosmology greatly extends the highly successful hot big-bang model. Now we have to make sense of all this: What is the dark matter particle? What is the nature of the dark energy? Why this mixture? How did the matter - antimatter asymmetry arise? What is the underlying cause of inflation (if it indeed occurred)? C1 Univ Chicago, Enrico Fermi Inst, Dept Astron & Astrophys, Ctr Cosmol Phys, Chicago, IL 60637 USA. Univ Chicago, Enrico Fermi Inst, Dept Phys, Chicago, IL 60637 USA. Fermilab Natl Accelerator Lab, NASA, Fermilab Astrophys Ctr, Batavia, IL 60510 USA. RP Univ Chicago, Enrico Fermi Inst, Dept Astron & Astrophys, Ctr Cosmol Phys, Chicago, IL 60637 USA. EM mturner@oddjob.uchicago.edu NR 47 TC 40 Z9 40 U1 0 U2 2 PU WORLD SCIENTIFIC PUBL CO PTE LTD PI SINGAPORE PA 5 TOH TUCK LINK, SINGAPORE 596224, SINGAPORE SN 0217-751X EI 1793-656X J9 INT J MOD PHYS A JI Int. J. Mod. Phys. A PD OCT PY 2002 VL 17 SU S BP 180 EP 196 DI 10.1142/S0217751X02013113 PG 17 WC Physics, Nuclear; Physics, Particles & Fields SC Physics GA 614AR UT WOS:000179165100018 ER PT J AU Gutman, G Justice, C Karnieli, A Arkin, Y AF Gutman, G Justice, C Karnieli, A Arkin, Y TI Cover-MODIS image of the Middle East SO INTERNATIONAL JOURNAL OF REMOTE SENSING LA English DT Article; Proceedings Paper CT International Workshop on Land Cover/Land Use Change and Water Management in Arid Regions CY OCT 23-27, 2000 CL BEN GURION UNIV NEGEV, BEER SHEVA, ISRAEL HO BEN GURION UNIV NEGEV ID SPECTRAL REFLECTANCE; SAND C1 NASA, Land Cover & Land Use Change Program, Washington, DC 20546 USA. Univ Maryland, Dept Geog, College Pk, MD 20742 USA. Ben Gurion Univ Negev, Jacob Blaustein Inst Desert Res, Remote Sensing Lab, IL-84990 Sede Boqer, Israel. Geol Survey Israel, IL-95501 Jerusalem, Israel. RP Gutman, G (reprint author), NASA, Land Cover & Land Use Change Program, NASA Headquarters,Code YS,300 E St SW,Room 5Q26, Washington, DC 20546 USA. NR 4 TC 0 Z9 0 U1 1 U2 1 PU TAYLOR & FRANCIS LTD PI ABINGDON PA 4 PARK SQUARE, MILTON PARK, ABINGDON OX14 4RN, OXON, ENGLAND SN 0143-1161 J9 INT J REMOTE SENS JI Int. J. Remote Sens. PD OCT PY 2002 VL 23 IS 19 BP 3905 EP 3907 DI 10.1080/01431160110115898 PG 3 WC Remote Sensing; Imaging Science & Photographic Technology SC Remote Sensing; Imaging Science & Photographic Technology GA 595JF UT WOS:000178104900001 ER PT J AU Lawrence, WT Imhoff, ML Kerle, N Stutzer, D AF Lawrence, WT Imhoff, ML Kerle, N Stutzer, D TI Quantifying urban land use and impact on soils in Egypt using diurnal satellite imagery of the Earth surface SO INTERNATIONAL JOURNAL OF REMOTE SENSING LA English DT Article; Proceedings Paper CT International Workshop on Land Cover/Land Use Change and Water Management in Arid Regions CY OCT 23-27, 2000 CL BEN GURION UNIV NEGEV, BEER SHEVA, ISRAEL HO BEN GURION UNIV NEGEV ID UNITED-STATES; CITY LIGHTS; POPULATION; BIODIVERSITY; URBANIZATION; EMISSIONS; SYSTEM AB Conversion of agricultural land to urban use represents a potential loss of agricultural productivity, especially in areas where arable land is in short supply. Using derived products from both daytime ( Landsat sensor data) and night-time imaging systems (U. S. Air Force Defense Meteorological Satellite Program's Operational Linescan System (DMSP/OLS)) we examined the impacts of urbanization on soils in Egypt; a country with very limited agricultural land. We concluded that urban land cover types to occupy 3.7% of the total area of Egypt and that over 30% of the soils most suitable for agriculture are under urban land cover. Analysis of multiyear historical DMSP/OLS data sets (digitized from paper images) proved unreliable for long-term urban growth estimates. C1 Bowie State Univ, Dept Nat Sci, Bowie, MD 20715 USA. NASA, Biospher Sci Branch, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Cambridge, Dept Geog, Cambridge CB2 1TN, England. RP Lawrence, WT (reprint author), Bowie State Univ, Dept Nat Sci, Bowie, MD 20715 USA. RI Kerle, Norman/A-5508-2010 NR 30 TC 19 Z9 20 U1 1 U2 13 PU TAYLOR & FRANCIS LTD PI ABINGDON PA 4 PARK SQUARE, MILTON PARK, ABINGDON OX14 4RN, OXON, ENGLAND SN 0143-1161 J9 INT J REMOTE SENS JI Int. J. Remote Sens. PD OCT PY 2002 VL 23 IS 19 BP 3921 EP 3937 DI 10.1080/01431160110115951 PG 17 WC Remote Sensing; Imaging Science & Photographic Technology SC Remote Sensing; Imaging Science & Photographic Technology GA 595JF UT WOS:000178104900003 ER PT J AU Otterman, J Karnieli, A Brakke, T Koslowsky, D Bolle, HJ Starr, D Schmidt, H AF Otterman, J Karnieli, A Brakke, T Koslowsky, D Bolle, HJ Starr, D Schmidt, H TI Desert scrub optical density and spectral-albedo ratios of impacted-toprotected areas by model inversion SO INTERNATIONAL JOURNAL OF REMOTE SENSING LA English DT Article; Proceedings Paper CT International Workshop on Land Cover/Land Use Change and Water Management in Arid Regions CY OCT 23-27, 2000 CL BEN GURION UNIV NEGEV, BEER SHEVA, ISRAEL HO BEN GURION UNIV NEGEV ID SURFACE ALBEDO; ARID REGIONS; SATELLITE; SOIL; REFLECTIVITIES; REFLECTANCES; LEAVES; PLANE AB Bidirectional surface reflectances measured from NOAA AVHRR over the Negev (southern Israel) and the Sinai are analysed to assess the impact on the surface characteristics of anthropogenic pressures of overgrazing. The impacted Sinai is assumed bare, while the Negev is vegetated by desert scrub. The Negev plants are known to be much darker than the underlying soil, and thus assumed to be absorbing ( black). The leaf area distribution as a function of the zenith angle is modelled initially as that of small spheres, which specifies a pronouncedly vertical architecture. We infer from the Negev-to-Sinai reflectance ratios the optical thickness tau(b) of the plants (spheres) in the range 0.12 to 0.20 for channel 1 (band centre at 0.63 mum), with only weak seasonal variability. Evaluated from average values of tau(b), the Negev-to-Sinai ratios of the spectral albedos (hemispheric reflectances) are 0.63 and 0.55 in channel 1 and 0.67 and 0.60 in channel 2, at solar zenith angles of 30degrees and 60degrees, respectively. These ratios indicate the severe climatic impact of overgrazing in the Sinai, inasmuch as a high albedo means reduced shortwave heat absorption (which is detrimental to rainfall-inducing convection). We subsequently proceed to invert the Negev-to-Sinai reflectance ratios assuming a plant-element distribution tending even more to the vertical. The values of tau(b) are reduced when derived for a greater tendency to vertical architecture. The Negev-to-Sinai ratios of the spectral albedos are also significantly lower in these cases, which means that the assessed impact of overgrazing in the Sinai is indeed extremely severe. We conclude that plant architecture (which controls the reflection anisotropy) should be considered when evaluating the albedos of vegetated versus bare ( impacted) surfaces from satellite-measured bidirectional reflectances. Uncertainty in the zenith angle distribution of the leaf area produces significant uncertainty in the albedo assessment. Multidirectional reflectance measurements made near the ground would greatly reduce uncertainties about the surface-reflection anisotropy, and thus enhance the value of satellite measurements. C1 NASA, Data Assimilat Off, GSFC, Greenbelt, MD 20771 USA. Desert Res Inst, Sede Boqer, Israel. NASA, Biospher Sci Branch, GSFC, Greenbelt, MD 20771 USA. Free Univ Berlin, D-12165 Berlin, Germany. NASA, Atmospher Sci Branch, GSFC, Greenbelt, MD 20771 USA. RP Otterman, J (reprint author), NASA, Data Assimilat Off, GSFC, Code 910-4, Greenbelt, MD 20771 USA. NR 33 TC 5 Z9 5 U1 0 U2 1 PU TAYLOR & FRANCIS LTD PI ABINGDON PA 4 PARK SQUARE, MILTON PARK, ABINGDON OX14 4RN, OXON, ENGLAND SN 0143-1161 J9 INT J REMOTE SENS JI Int. J. Remote Sens. PD OCT PY 2002 VL 23 IS 19 BP 3959 EP 3970 DI 10.1080/01431160110115753 PG 12 WC Remote Sensing; Imaging Science & Photographic Technology SC Remote Sensing; Imaging Science & Photographic Technology GA 595JF UT WOS:000178104900005 ER PT J AU Martin, LC Kiser, JD Lei, JF Singh, M Cuy, M Blaha, CA Androjna, D AF Martin, LC Kiser, JD Lei, JF Singh, M Cuy, M Blaha, CA Androjna, D TI Attachment technique for securing sensor lead wires on SiC-based components SO JOURNAL OF ADVANCED MATERIALS LA English DT Article ID SILICON-CARBIDE CERAMICS AB An enhanced attachment technique for securing sensor lead wires on silicon carbide (SiC)-based components is being developed to improve the durability of a minimally-intrusive thin film-based sensor system. The attachment method utilizes a ceramic joining technology to bond monolithic SiC or SiC fiber-reiqforced SiC ceramic matrix composite (SiC/SiC CMC) hoops on SiC-based components. Testing of instrumented SiC/SiC CMC panels in a Mach 0.3 burner rig indicated that this approach provides improved lead wire attachments over current techniques. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. QSS Grp Inc, Cleveland, OH USA. Akima Corp, Cleveland, OH USA. RP Martin, LC (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. NR 21 TC 0 Z9 0 U1 0 U2 0 PU SAMPE PUBLISHERS PI COVINA PA 1161 PARKVIEW DRIVE, COVINA, CA 91722 USA SN 1070-9789 J9 J ADV MATER-COVINA JI J. Adv. Mater. PD OCT PY 2002 VL 34 IS 4 BP 34 EP 40 PG 7 WC Materials Science, Multidisciplinary SC Materials Science GA 596AR UT WOS:000178141800007 ER PT J AU Noor, AK Starnes, JH Peters, JM AF Noor, AK Starnes, JH Peters, JM TI Thermomechanical response variability of stiffened composite panels SO JOURNAL OF AEROSPACE ENGINEERING LA English DT Article DE panels; composite materials; stiffening; loads; nonlinear response; sensitivity analysis; thermal factors ID REDUCED BASIS TECHNIQUE AB A study is made of the variability of the response of stiffened composite panels, associated with variations in the major geometric and material parameters of the structures. The major parameters, which have the most effect on the response quantities of interest, are identified by using a hierarchical sensitivity analysis. The range of variation of the response is determined by using a fuzzy set analysis, with the major parameters treated as fuzzy parameters. Numerical results are presented showing the variability of the response of panels with both continuous and terminated stiffeners associated with variations in the micromechanical, effective layer, and geometric parameters. Both flat and curved panels are considered. C1 Old Dominion Univ, NASA, Langley Res Ctr, Ctr Adv Engn Environm, Hampton, VA 23681 USA. Univ Florida, Gainesville, FL 32611 USA. NASA, Langley Res Ctr, Struct & Mat Competency, Hampton, VA 23681 USA. RP Noor, AK (reprint author), Old Dominion Univ, NASA, Langley Res Ctr, Ctr Adv Engn Environm, MS 201, Hampton, VA 23681 USA. NR 18 TC 0 Z9 0 U1 0 U2 2 PU ASCE-AMER SOC CIVIL ENGINEERS PI RESTON PA 1801 ALEXANDER BELL DR, RESTON, VA 20191-4400 USA SN 0893-1321 J9 J AEROSPACE ENG JI J. Aerosp. Eng. PD OCT PY 2002 VL 15 IS 4 BP 154 EP 164 DI 10.1061/(ASCE)0893-1321(2002)15:4(154) PG 11 WC Engineering, Aerospace; Engineering, Civil SC Engineering GA 598AG UT WOS:000178252500003 ER PT J AU McFerrin, MB Snell, EH AF McFerrin, MB Snell, EH TI The development and application of a method to quantify the quality of cryoprotectant solutions using standard area-detector X-ray images SO JOURNAL OF APPLIED CRYSTALLOGRAPHY LA English DT Article ID CRYSTALLIZATION; CRYOCRYSTALLOGRAPHY; VITRIFICATION; DIFFRACTION AB An X-ray based method for determining initial cryoprotectant concentrations necessary to protect solutions from crystalline ice formation on flash cooling was developed. X-ray images from a charge-coupled device (CCD) area detector were integrated as powder patterns and quantified by determining the standard deviation of the slope of the normalized intensity curve in the resolution range where ice rings are known to occur. The method was tested by determining the concentrations of glycerol, PEG400, ethylene glycol and 1,2-propanediol necessary to form an amorphous glass at 100 K with each of the 98 crystallization solutions of Crystal Screens I and II (Hampton Research, Laguna Hills, California, USA). For conditions that required glycerol concentrations of 35% or above, cryoprotectant conditions using (2R,3R)-(-)2,3-butanediol were determined. The method proved to be remarkably reliable. The results build on previous work [Garman & Mitchell (1996). J. Appl. Cryst. 29, 584-587] and extend the number of suitable starting conditions to alternative cryoprotectants. C1 NASA, George C Marshall Space Flight Ctr, Struct Biol Lab, Huntsville, AL 35812 USA. RP Snell, EH (reprint author), NASA, George C Marshall Space Flight Ctr, Struct Biol Lab, Code SD46, Huntsville, AL 35812 USA. NR 16 TC 32 Z9 33 U1 1 U2 9 PU BLACKWELL MUNKSGAARD PI COPENHAGEN PA 35 NORRE SOGADE, PO BOX 2148, DK-1016 COPENHAGEN, DENMARK SN 0021-8898 J9 J APPL CRYSTALLOGR JI J. Appl. Crystallogr. PD OCT PY 2002 VL 35 BP 538 EP 545 DI 10.1107/S0021889802009238 PN 5 PG 8 WC Chemistry, Multidisciplinary; Crystallography SC Chemistry; Crystallography GA 590DN UT WOS:000177802800004 ER PT J AU Daube, BC Boering, KA Andrews, AE Wofsy, SC AF Daube, BC Boering, KA Andrews, AE Wofsy, SC TI A high-precision fast-response airborne CO2 analyzer for in situ sampling from the surface to the middle stratosphere SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article ID EMPIRICAL AGE SPECTRA; CARBON-DIOXIDE; TRANSPORT; TROPOSPHERE; N2O; AIR; CH4; MIDLATITUDES; SPECTROMETER; AIRCRAFT AB Two in situ CO2 analyzers have been developed for deployment on the NASA ER-2 aircraft and on stratospheric balloons. The ER-2 instrument has had more than 150 flights during 21 deployments from 1992 to 2000, resulting in a dataset with nearly pole-to-pole coverage that includes data from all seasons in both hemispheres except austral summer. In-flight calibrations show that the typical long-term (i.e., flight-to-flight) precision of the instruments is better than +/-0.1 ppmv. The flight standards are traceable to standards held by the Scripps Institute of Oceanography and the National Oceanic and Atmospheric Administration's Climate Monitoring and Diagnostics Laboratory. The balloon instrument has had eight balloon flights since September 1996, providing the first in situ observations of CO2 above similar to21 km. In addition, the balloon instrument has been flown on board a Cessna Citation II aircraft for sampling between the surface and 10 km. In this paper, the instrumentation and calibration procedures for both instruments are described in detail. An intercomparison of the two instruments during the Photochemistry of Ozone Loss in the Arctic Region In Summer (POLARIS) project showed that, on average, the instruments agreed to within 0.05 ppmv. C1 Harvard Univ, Dept Earth & Planetary Sci, Cambridge, MA 02138 USA. Harvard Univ, Div Engn & Appl Sci, Cambridge, MA 02138 USA. RP Andrews, AE (reprint author), NASA, Goddard Space Flight Ctr, Mailstop 916-0, Greenbelt, MD 20771 USA. RI Andrews, Arlyn/K-3427-2012 NR 31 TC 51 Z9 51 U1 0 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 OCT PY 2002 VL 19 IS 10 BP 1532 EP 1543 DI 10.1175/1520-0426(2002)019<1532:AHPFRA>2.0.CO;2 PG 12 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA 596XY UT WOS:000178192800004 ER PT J AU Jin, ZH Charlock, TP Rutledge, K AF Jin, ZH Charlock, TP Rutledge, K TI Analysis of broadband solar radiation and albedo over the ocean surface at COVE SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article ID SPECTRAL REFLECTANCE; OPTICAL-PROPERTIES; THERMAL OFFSET; LAYERED MEDIA; SCATTERING; ALGORITHM; BUBBLES; LIGHT; TRANSMISSION; PYRANOMETER AB A coupled atmosphere-ocean radiative transfer model has been applied to analyze a full year of broadband solar irradiances (up and down) measured over an ocean site 25 km east of the coast of Virginia in the Atlantic. The coupled model treats absorption and scattering by layers for both the atmosphere and the ocean explicitly and consistently. Key input parameters for the model (aerosol optical depth, wind speed, and total precipitable water) are also from in situ measurements. Having more observations to specify properties of the atmosphere than of the ocean, better model-observation agreement is obtained for the downwelling irradiance, which depends primarily on the atmospheric optical properties, than for the upwelling irradiance, which depends heavily on the ocean optical properties. The mean model-observation differences for the ocean surface albedo are generally less than 0.01. However, the modeled upwelling irradiances and albedo over the ocean surface are mostly less than the observations for all seasons, implying that more scattering in the ocean needs to be included in the model calculations. Sensitivity tests indicate that the uncertainties in aerosol optical properties, chlorophyll concentration, wind speed, or foams are not the primary factors for the model-observation differences in the ocean surface albedo, whereas the scattering by air bubbles and/or by suspended materials have the potential to significantly reduce or eliminate the model-observation differences in the ocean surface reflection. C1 Analyt Serv & Mat Inc, Hampton, VA 23666 USA. NASA, Langley Res Ctr, Div Atmospher Sci, Hampton, VA 23665 USA. RP Jin, ZH (reprint author), Analyt Serv & Mat Inc, 1 Enterprise Pkwy,Suite 300, Hampton, VA 23666 USA. NR 40 TC 44 Z9 47 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 OCT PY 2002 VL 19 IS 10 BP 1585 EP 1601 DI 10.1175/1520-0426(2002)019<1585:AOBSRA>2.0.CO;2 PG 17 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA 596XY UT WOS:000178192800009 ER PT J AU Bay, SD Shrager, J Pohorille, A Langley, P AF Bay, SD Shrager, J Pohorille, A Langley, P TI Revising regulatory networks: from expression data to linear causal models SO JOURNAL OF BIOMEDICAL INFORMATICS LA English DT Article DE gene networks; gene regulation; revision; modeling AB Discovering the complex regulatory networks that govern mRNA expression is an important but difficult problem. Many current approaches use only expression data from microarrays to infer the likely network structure. However, this ignores much existing knowledge because for a given organism and system under study, a biologist may already have a partial model of gene regulation. We propose a method for revising and improving these initial models, which may be incomplete or partially incorrect, with expression data. We demonstrate our approach by revising a model of photosynthesis regulation proposed by a biologist for Cyanobacteria. Applied to wild type expression data, our system suggested several modifications consistent with biological knowledge. Applied to a mutant strain, our system correctly modified the disabled gene. Power experiments with synthetic data that indicate that reliable revision is feasible even with a small number of samples. (C) 2003 Elsevier Science (USA). All rights reserved. C1 Inst Study Learning & Expertise, Palo Alto, CA 94306 USA. Carnegie Inst Sci, Dept Plant Biol, Washington, DC 20005 USA. NASA, Ames Res Ctr, Ctr Computat Astrobiol & Fundamental Biol, Moffett Field, CA 94305 USA. RP Stanford Univ, Computat Learning Lab, CSL1,Ventura Hall, Stanford, CA 94305 USA. EM sbay@apres.stanford.edu NR 22 TC 11 Z9 11 U1 0 U2 1 PU ACADEMIC PRESS INC ELSEVIER SCIENCE PI SAN DIEGO PA 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA SN 1532-0464 EI 1532-0480 J9 J BIOMED INFORM JI J. Biomed. Inform. PD OCT-DEC PY 2002 VL 35 IS 5-6 BP 289 EP 297 DI 10.1016/S1532-0464(03)00031-5 PG 9 WC Computer Science, Interdisciplinary Applications; Medical Informatics SC Computer Science; Medical Informatics GA 713VQ UT WOS:000184879000002 PM 12968777 ER PT J AU Chuck, RS Arnoldussen, ME Behrens, A Sweet, PM Bearman, GH Grundfest, WS AF Chuck, RS Arnoldussen, ME Behrens, A Sweet, PM Bearman, GH Grundfest, WS TI Fluorescence-guided laser removal of chemically damaged cornea SO JOURNAL OF CATARACT AND REFRACTIVE SURGERY LA English DT Article ID SPECTROSCOPY; ABLATION; SPECTRA AB Purpose: To correlate the observed fluorescence spectrum with the depth of ablation during 193 nm argon-fluoride excimer laser ablation of chemically damaged corneas. Setting: Laser facility, Cedars-Sinai Medical Center, Los Angeles, California, USA. Methods: Three cadaver New Zealand white rabbit corneas were exposed to 1 N hydrogen chloride for 10 seconds. The resultant opaque corneas were ablated to perforation using the excimer laser. Laser-induced fluorescence was collected at 45 degrees from incidence and channeled into an ultraviolet-visible spectrometer coupled to an optical multichannel analyzer reading a diode array detector. The detector recorded single-shot fluorescence spectra. The data were examined by principal component analysis, and the evolution of eigenvectors and their weighting coefficients were used to compare data among corneas. The results were correlated with histopathological sections. Results: The eigenvalues of 3 principal components corresponded to 88.9%, 10.0%, and 0.4% of the data in acid-burned corneas. Compared to that in undamaged corneas, more information was stored in the first principal component and the third eigenvector was distinctly altered. Acid-scarred tissue blue shifted the dominant fluorescence peak compared to that in normal corneal tissue. Conclusions: After severe hydrogen chloride burn to the rabbit corneal surface, monitoring the dominant peak wavelength shift of excimer-laser-induced fluorescence can detect the transition between severely acid-damaged and underlying tissue. (C) 2002 ASCRS and ESCRS. C1 Univ Calif Irvine, Dept Ophthalmol, Irvine, CA 92697 USA. Cedars Sinai Med Ctr, Los Angeles, CA 90048 USA. Univ So Calif, Los Angeles, CA USA. CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. Univ Calif Los Angeles, Dept Elect Engn, Los Angeles, CA 90024 USA. RP Chuck, RS (reprint author), Univ Calif Irvine, Dept Ophthalmol, 118 Med Surge 1, Irvine, CA 92697 USA. NR 18 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0886-3350 J9 J CATARACT REFR SURG JI J. Cataract. Refract. Surg. PD OCT PY 2002 VL 28 IS 10 BP 1847 EP 1852 AR PII S0886-3350(02)01361-5 DI 10.1016/S0886-3350(02)01361-5 PG 6 WC Ophthalmology; Surgery SC Ophthalmology; Surgery GA 605GW UT WOS:000178670400029 PM 12388040 ER PT J AU Chickos, JS Hillesheim, D Nichols, G Zehe, MJ AF Chickos, JS Hillesheim, D Nichols, G Zehe, MJ TI The enthalpies of vaporization and sublimation of exo- and endo-tetrahydrodicyclopentadienes at T=298.15 K SO JOURNAL OF CHEMICAL THERMODYNAMICS LA English DT Article ID ORGANIC LIQUIDS; HYDROCARBONS; CALORIMETRY; SOLIDS; FUELS AB The vaporization enthalpies {Delta(1)(g)H(m) (298.15 K)} of endo- and exo-tetrahydrodicyclopentadiene (THDCPD) have been measured by correlation gas chromatography. Values of (50.2 +/- 2.3) kJ.mol(-1) and (49.1 +/- 2.3) kJ.mol(-1) have been obtained for the endo and exo isomers, respectively. The sublimation enthalpy of the endo isomer {Delta(cr)(g)H(m) (298.15 K) = (51.2 +/- 2.4) kJ.mol(-1)} has been obtained by combining fusion and vaporization enthalpies adjusted as necessary to T = 298.15 K. Low-temperature d.s.c. studies of both isomers reveal solid-to-solid phase transitions. The endo isomer, which is a plastic crystal at room temperature, exhibits a solid-to-solid phase transition at T = 214 K {Delta(cr(2))(cr(1))H(m)(214K) = (10.7 +/- 0.13) kJ.mol(-1)} and a melting temperature of 356.8 K {Delta(cr(1))(1)H(m)(356.8 K) = (3.48 +/- 0.2) kJ.mol(-1)} with some evidence of polymorphism. The exo isomer exhibits a solid phase transition at T = 162.1 K {Delta(cr(2))(cr(1))H(m) (162.1 K) = (3.18 +/- 0.11) kJ.mol(-1)} and a melting temperature of 183.2 K {Delta(cr(1))(1)H(m) (183.2 K) = (1.20 +/- 0.04) kJ.mol(-1)}. Enthalpies of vaporization and sublimation are combined with the respective enthalpies of formation previously reported to yield the following gas-phase values: for endo THDCPD, Delta(f)H(m)degrees = -(61.9 +/- 3.2) kJ.mol(-1); and for C1 Univ Missouri, Dept Chem, St Louis, MO 63121 USA. NASA, John Glenn Res Ctr, Cleveland, OH 44135 USA. RP Chickos, JS (reprint author), Univ Missouri, Dept Chem, St Louis, MO 63121 USA. EM jsc@umsl.edu NR 19 TC 14 Z9 14 U1 1 U2 5 PU ACADEMIC PRESS LTD ELSEVIER SCIENCE LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 0021-9614 J9 J CHEM THERMODYN JI J. Chem. Thermodyn. PD OCT PY 2002 VL 34 IS 10 BP 1647 EP 1658 DI 10.1016/S0021-9614(02)00229-X PG 12 WC Thermodynamics; Chemistry, Physical SC Thermodynamics; Chemistry GA 620FE UT WOS:000179522700011 ER PT J AU Kang, IS Jin, K Lau, KM Shukla, J Krishnamurthy, V Schubert, SD Waliser, DE Stern, WF Satyan, V Kitoh, A Meehl, GA Kanamitsu, M Galin, VY Sumi, A Wu, G Liu, Y Kim, JK AF Kang, IS Jin, K Lau, KM Shukla, J Krishnamurthy, V Schubert, SD Waliser, DE Stern, WF Satyan, V Kitoh, A Meehl, GA Kanamitsu, M Galin, VY Sumi, A Wu, G Liu, Y Kim, JK TI Intercomparison of atmospheric GCM simulated anomalies associated with the 1997/98 El Nino SO JOURNAL OF CLIMATE LA English DT Article ID GENERAL-CIRCULATION MODEL; COMMUNITY CLIMATE MODEL; SOUTHERN OSCILLATION; SURFACE-TEMPERATURE; ARAKAWA-SCHUBERT; SOLAR-RADIATION; SCHEME; PARAMETERIZATION; PATTERNS; VARIABILITY AB The atmospheric anomalies for the 1997/98 El Nino-Southern Oscillation (ENSO) period have been analyzed and intercompared using the data simulated by the atmospheric general circulation models (GCMs) of 11 groups participating in the Monsoon GCM Intercomparison Project initiated by the Climate Variability and Prediction Program (CLIVAR)/Asian-Australian Monsoon Panel. Each participating GCM group performed a set of 10 ensemble simulations for 1 September 1996-31 August 1998 using the same sea surface temperature (SST) conditions but with different initial conditions. The present study presents an overview of the intercomparison project and the results of an intercomparison of the global atmospheric anomalies during the 1997/98 El Nino period. Particularly, the focus is on the tropical precipitation anomalies over the monsoon-ENSO region and the upper-tropospheric circulation anomalies in the Pacific-North American (PNA) region. The simulated precipitation anomalies show that all of the models simulate the spatial pattern of the observed anomalies reasonably well in the tropical central Pacific, although there are large differences in the amplitudes. However, most of the models have difficulty in simulating the negative anomalies over the Maritime Continent during El Nino. The 200-hPa geopotential anomalies over the PNA region are reasonably well reproduced by most of the models. But, the models generally underestimate the amplitude of the PNA pattern. These weak amplitudes are related to the weak precipitation anomalies in the tropical Pacific. The tropical precipitation anomalies are found to be closely related to the SST anomalies not only during the El Nino seasons but also during the normal seasons that are typified by weak SST anomalies in the tropical Pacific. In particular, the pattern correlation values of the 11-model composite of the precipitation anomalies with the observed counterparts for the normal seasons are near 0.5 for the tropical region between 30degreesS and 30degreesN. C1 Seoul Natl Univ, Sch Earth & Environm Sci, Seoul 151742, South Korea. NASA, Goddard Space Flight Ctr, Climate & Radiat Branch, Greenbelt, MD 20771 USA. SUNY Stony Brook, Inst Terr & Planetary Atmospheres, Stony Brook, NY 11794 USA. Princeton Univ, NOAA, Geophys Fluid Dynam Lab, Princeton, NJ 08544 USA. Indian Inst Trop Meteorol, Pune, Maharashtra, India. Meteorol Res Inst, Tsukuba, Ibaraki 305, Japan. Natl Ctr Atmospher Res, Boulder, CO 80307 USA. Natl Ctr Environm Predict, Camp Springs, MD USA. Russian Acad Sci, Inst Numer Math, Moscow, Russia. Univ Tokyo, Ctr Climate Syst Res, Tokyo, Japan. Chinese Acad Sci, Inst Atmospher Phys, Beijing, Peoples R China. Inst Global Environm & Soc Inc, Ctr Ocean Land Atmosphere Studies, Calverton, MD USA. NASA, Goddard Space Flight Ctr, Data Assimilat Off, Greenbelt, MD 20771 USA. RP Kang, IS (reprint author), Seoul Natl Univ, Sch Earth & Environm Sci, Seoul 151742, South Korea. EM kang@climate.snu.ac.kr RI Lau, William /E-1510-2012; 안, 민섭/D-9972-2015 OI Lau, William /0000-0002-3587-3691; NR 61 TC 54 Z9 58 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 OCT PY 2002 VL 15 IS 19 BP 2791 EP 2805 DI 10.1175/1520-0442(2002)015<2791:IOAGSA>2.0.CO;2 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 593RQ UT WOS:000178006300005 ER PT J AU Luo, ZZ Rossow, WB Inoue, T Stubenrauch, CJ AF Luo, ZZ Rossow, WB Inoue, T Stubenrauch, CJ TI Did the eruption of the Mt. Pinatubo Volcano affect cirrus properties? SO JOURNAL OF CLIMATE LA English DT Article ID SATELLITE SOUNDERS 3I; GENERAL-CIRCULATION MODEL; SPLIT-WINDOW MEASUREMENTS; CLOUD-TOP TEMPERATURE; HIGH-LEVEL CLOUDS; TIROS-N SERIES; RADIATIVE PROPERTIES; IMAGERS ISCCP; CLIMATE MODELS; AEROSOLS AB Some observations suggest that the volcanic aerosols produced by the Mt. Pinatubo eruption may have altered cirrus. The authors look for evidence that such modification of cirrus is extensive enough to be climatically significant by comparing three satellite-based cirrus datasets produced by the International Satellite Cloud Climatology Project (ISCCP) analysis, the split-window analysis, and the Improved Initialization Inversion (3I) analysis. Since the former two have not been compared in detail before, such a comparison was conducted here. When applied to the Advanced Very High Resolution Radiometer (AVHRR) data, both the ISCCP and split-window analyses identify about 0.2-0.3 cirrus cloud amounts in tropical latitudes; however, there are detailed differences of classification for about half of these clouds. The discrepancies are attributed to the simplified assumptions made by both methods. The latter two datasets are derived from infrared radiances, so they are less sensitive to volcanic aerosols than the ISCCP analysis. After the Mt. Pinatubo eruption, the ISCCP results indicate a notable decrease of thin cirrus over ocean, accompanied by a comparable increase of altocumulus and cumulus clouds; over land, there are no significant changes. In contrast, results from the split-window and 3I analyses show little change in thin cirrus amount over either ocean or land that is associated with the volcanic eruption. The ISCCP results can, therefore, be understood as a misclassification of thin cirrus because additional reflected sunlight by the volcanic aerosol makes the cirrus clouds appear to be optically thicker. Examinations of the split-window signature show no significant change in infrared emissivity (or optical thickness). These results indicate that the Mt. Pinatubo volcanic aerosol did not have a significant systematic effect on tropical cirrus properties (such as cloud amount and optical thickness), but do not exclude the occurrence of temporary, local effects. Hence, these results suggest that there is no significant climate feedback produced by aerosol-cirrus-radiative interactions. C1 Columbia Univ, Dept Earth & Environm Sci, New York, NY 10025 USA. NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Meteorol Res Inst, Tsukuba, Ibaraki 305, Japan. Ecole Polytech, CNRS, Meteorol Dynam Lab, F-91128 Palaiseau, France. RP Luo, ZZ (reprint author), Columbia Univ, Dept Earth & Environm Sci, 2880 Broadway,Room 608, New York, NY 10025 USA. RI INOUE, Toshiro/C-9597-2014; Rossow, William/F-3138-2015 NR 46 TC 39 Z9 39 U1 0 U2 5 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8755 J9 J CLIMATE JI J. Clim. PD OCT PY 2002 VL 15 IS 19 BP 2806 EP 2820 DI 10.1175/1520-0442(2002)015<2806:DTEOTM>2.0.CO;2 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 593RQ UT WOS:000178006300006 ER PT J AU Wu, MLC Schubert, A Kang, IS Waliser, D AF Wu, MLC Schubert, A Kang, IS Waliser, D TI Forced and free intraseasonal variability over the South Asian monsoon region simulated by 10 AGCMs SO JOURNAL OF CLIMATE LA English DT Article ID MADDEN-JULIAN OSCILLATION; SEA-SURFACE TEMPERATURE; TROPICAL WESTERN PACIFIC; GLOBAL PRECIPITATION; SUMMER MONSOON; FLUXES; MODEL; OCEAN; REANALYSIS; SCALE AB This study examines intraseasonal (20-70 day) variability in the South Asian monsoon region during 1997/ 98 in ensembles of 10 simulations with 10 different atmospheric general circulation models. The 10 ensemble members for each model are forced with the same observed weekly sea surface temperature (SST) but differ from each other in that they are started from different initial atmospheric conditions. The results show considerable differences between the models in the simulated 20-70-day variability, ranging from much weaker to much stronger than the observed. A key result is that the models do produce, to varying degrees, a response to the imposed weekly SST. The forced variability tends to be largest in the Indian and western Pacific Oceans where, for some models, it accounts for more than a quarter of the 20-70-day intraseasonal variability in the upper-level velocity potential during these two years. A case study of a strong observed Madden-Julian oscillation (MJO) event shows that the models produce an ensemble mean eastward-propagating signal in the tropical precipitation field over the Indian Ocean and western Pacific, similar to that found in the observations. The associated forced 200-mb velocity potential anomalies are strongly phase locked with the precipitation anomalies, propagating slowly to the east (about 5 m s(-1)) with a local zonal wavenumber-2 pattern that is generally consistent with the developing observed MJO. The simulated and observed events are, however, approximately in quadrature, with the simulated response leading by 5-10 days. The phase lag occurs because, in the observations, the positive SST anomalies develop upstream of the main convective center in the subsidence region of the MJO, while in the simulations, the forced component is in phase with the SST. For all the models examined here, the intraseasonal variability is dominated by the free (intraensemble) component. The results of the case study presented here show that the free variability has a predominately zonal wavenumber-1 pattern, and has propagation speeds (10-15 m s(-1)) that are more typical of observed MJO behavior away from the convectively active regions. The free variability appears to be synchronized with the forced response, at least during the strong event examined here. The results of this study support the idea that coupling with SSTs plays an important, though probably not dominant, role in the MJO. The magnitude of the atmospheric response to the SST appears to be in the range of 15%-30% of the 20-70-day variability over much of the tropical eastern Indian and western Pacific Oceans. The results also highlight the need to use caution when interpreting atmospheric model simulations in which the prescribed SST resolves MJO timescales. C1 NASA, Goddard Space Flight Ctr, Data assimilat Off, Greenbelt, MD 20771 USA. Seoul Natl Univ, Sch Earth & Environm Sci, Seoul, South Korea. SUNY Stony Brook, Inst Terr & Planetary Atmospheres, Stony Brook, NY 11794 USA. RP Wu, MLC (reprint author), NASA, Goddard Space Flight Ctr, Data assimilat Off, Greenbelt, MD 20771 USA. RI 안, 민섭/D-9972-2015 NR 29 TC 44 Z9 46 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8755 J9 J CLIMATE JI J. Clim. PD OCT PY 2002 VL 15 IS 20 BP 2862 EP 2880 DI 10.1175/1520-0442(2002)015<2862:FAFIVO>2.0.CO;2 PG 19 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 596XX UT WOS:000178192700002 ER PT J AU Luthcke, SB Ekholm, S Blair, JB AF Luthcke, SB Ekholm, S Blair, JB TI Laser altimetry - Introduction SO JOURNAL OF GEODYNAMICS LA English DT Editorial Material C1 NASA, Goddard Space Flight Ctr, Space Geodesy Branch, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Laser Remote Sensing Branch, Greenbelt, MD USA. RP Luthcke, SB (reprint author), NASA, Goddard Space Flight Ctr, Space Geodesy Branch, Greenbelt, MD 20771 USA. RI Luthcke, Scott/D-6283-2012; Blair, James/D-3881-2013 NR 0 TC 0 Z9 0 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0264-3707 J9 J GEODYN JI J. Geodyn. PD OCT-NOV PY 2002 VL 34 IS 3-4 BP 343 EP 345 AR PII S0264-3707(02)00091-1 DI 10.1016/S0264-3707(02)00091-1 PG 3 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 602BK UT WOS:000178484800001 ER PT J AU Krabill, WB Abdalati, W Frederick, EB Manizade, SS Martin, CF Sonntag, JG Swift, RN Thomas, RH Yungel, JG AF Krabill, WB Abdalati, W Frederick, EB Manizade, SS Martin, CF Sonntag, JG Swift, RN Thomas, RH Yungel, JG TI Aircraft laser altimetry measurement of elevation changes of the greenland ice sheet: technique and accuracy assessment SO JOURNAL OF GEODYNAMICS LA English DT Article AB Airborne laser altimetry has been used during the past decade to measure the surface elevation of the Greenland ice sheet. These measurements have been made using a scanning laser on a NASA P-3 aircraft which was positioned by differential GPS and flown approximately 500 m above the surface. Flights have been made over major portions of the ice sheet and reflown 5 years later in order to obtain estimates of the rate of overall change of surface elevation. The accuracy with which differential elevations can be made depends upon (a) the GPS positioning accuracy, (b) the instrument calibration accuracy, (c) the stability of the laser and, (d) the accuracy of the aircraft inertial navigation system's estimation of aircraft attitude. Overall, the accuracy of an elevation change estimate is computed to be 8.5 cm over small areas and 7.1 cm when averaged over tens of kilometers as is needed for estimating ice volume changes. This effort supports +/-1.4 cm/year resolution for long period surface elevation changes from data acquired which are separated by 5 years. Results of inflight data analyses are consistent with these accuracy estimates. Published by Elsevier Science Ltd. C1 NASA, Goddard Space Flight Ctr, Lab Hydrospher Proc, Wallops Isl, VA 23337 USA. EG&G Tech Serv, Gaithersburg, MD 20878 USA. NASA, Wallops Flight Facil, EG&G Tech Serv, Wallops Isl, VA 23337 USA. NASA Headquarters, Off Earth Sci, Washington, DC 20546 USA. RP Krabill, WB (reprint author), NASA, Goddard Space Flight Ctr, Lab Hydrospher Proc, Code 972, Wallops Isl, VA 23337 USA. NR 8 TC 104 Z9 109 U1 1 U2 10 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0264-3707 J9 J GEODYN JI J. Geodyn. PD OCT-NOV PY 2002 VL 34 IS 3-4 BP 357 EP 376 AR PII S0264-3707(02)00040-6 DI 10.1016/S0264-3707(02)00040-6 PG 20 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 602BK UT WOS:000178484800003 ER PT J AU Ekholm, S Bamber, JL Krabill, WB AF Ekholm, S Bamber, JL Krabill, WB TI The use of airborne laser data to calibrate satellite radar altimetry data over ice sheets SO JOURNAL OF GEODYNAMICS LA English DT Article ID TOPOGRAPHY; ACCURACY AB Satellite radar altimetry is the most important data source for ice sheet elevation modeling but it is well established that the accuracy of such data from satellite borne radar altimeters degrade seriously with increasing surface slope and level of roughness. A significant fraction of the slope-correlated noise can be effectively removed by the so-called relocation error correction method. The adjustment, however, produces a different spatial sampling of the data, which introduces a non-negligible slope related bias to the computation of digital elevation models. In this paper we incorporate high-precision airborne laser profiling data from the so-called Arctic Ice Mapping project as a tool to determine that bias and to calibrate the satellite altimetry. This is achieved by a simple statistical analysis of the airborne laser profiles, which defines the mean amplitude of the local surface undulations as a linear function of surface slope. This linear correspondence is in turn tested as a model for adjusting the satellite altimetry data for the observed slope correlated bias. The adjustment is shown to have a significant effect in terms of reducing the bias, thus improving the modeling accuracy of the data. (C) 2002 Elsevier Science Ltd. All rights reserved. C1 Kort & Matrikelstyrelsen Natl Survey & Cadastre, DK-2400 Copenhagen NV, Denmark. Univ Bristol, Ctr Remote Sensing, Bristol BS2 1SS, Avon, England. NASA, Goddard Space Flight Ctr, Wallops Flight Facil, Wallops Isl, VA 23337 USA. RP Ekholm, S (reprint author), Kort & Matrikelstyrelsen Natl Survey & Cadastre, Rentemestervej 8, DK-2400 Copenhagen NV, Denmark. RI Bamber, Jonathan/C-7608-2011 OI Bamber, Jonathan/0000-0002-2280-2819 NR 14 TC 2 Z9 2 U1 0 U2 3 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0264-3707 J9 J GEODYN JI J. Geodyn. PD OCT-NOV PY 2002 VL 34 IS 3-4 BP 377 EP 390 AR PII S0264-3707(02)00041-8 DI 10.1016/S0264-3707(02)00041-8 PG 14 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 602BK UT WOS:000178484800004 ER PT J AU Abdalati, W Krabill, W Frederick, E Manizade, S Martin, C Sonntag, J Swift, R Thomas, R Wright, W Yungel, J AF Abdalati, W Krabill, W Frederick, E Manizade, S Martin, C Sonntag, J Swift, R Thomas, R Wright, W Yungel, J TI Airborne laser altimetry mapping of the Greenland ice sheet: application to mass balance assessment SO JOURNAL OF GEODYNAMICS LA English DT Article ID ACCUMULATION; GROWTH AB In 1998 and 1999, the Arctic Ice Mapping (AIM) program completed resurveys of flight lines occupied 5 years earlier revealing elevation changes of the Greenland ice sheet and identifying areas of significant thinning, thickening and balance. In planning these surveys, consideration had to be given to the spatial constraints associated with aircraft operation, the spatial nature of ice sheet behavior, and limited resources, as well as temporal issues, such as seasonal and interannual variability in the context of measurement accuracy. The surveys covered the entire ice sheet with an average distance of 21.4 kin between each location on the ice sheet and the nearest flight line. For most of the ice sheet, the elevation changes show relatively little spatial variability, and their magnitudes are significantly smaller than the observed elevation change signal. As a result, we conclude that the density of the sampling and the accuracy of the measurements are sufficient to draw meaningful conclusions on the state of balance of the entire ice sheet over the 5-year survey period. Outlet glaciers, however, show far more spatial and temporal variability, and each of the major ones is likely to require individual surveys in order to determine its balance. (C) 2002 Elsevier Science Ltd. All rights reserved. C1 NASA Headquarters, Off Earth Sci, Washington, DC 20546 USA. NASA, Goddard Space Flight Ctr, Wallops Flight Facil, EG&G Serv, Wallops Isl, VA 23336 USA. RP Abdalati, W (reprint author), NASA Headquarters, Off Earth Sci, Code YS, Washington, DC 20546 USA. NR 23 TC 8 Z9 8 U1 0 U2 3 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0264-3707 J9 J GEODYN JI J. Geodyn. PD OCT-NOV PY 2002 VL 34 IS 3-4 BP 391 EP 403 AR PII S0264-3707(02)00048-0 DI 10.1016/S0264-3707(02)00048-0 PG 13 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 602BK UT WOS:000178484800005 ER PT J AU Zwally, HJ Schutz, B Abdalati, W Abshire, J Bentley, C Brenner, A Bufton, J Dezio, J Hancock, D Harding, D Herring, T Minster, B Quinn, K Palm, S Spinhirne, J Thomas, R AF Zwally, HJ Schutz, B Abdalati, W Abshire, J Bentley, C Brenner, A Bufton, J Dezio, J Hancock, D Harding, D Herring, T Minster, B Quinn, K Palm, S Spinhirne, J Thomas, R TI ICESat's laser measurements of polar ice, atmosphere, ocean, and land SO JOURNAL OF GEODYNAMICS LA English DT Article ID DYNAMIC ORBIT DETERMINATION; KM AVHRR DATA; ELEVATION-CHANGE; GPS MEASUREMENTS; AIRBORNE LIDAR; TOPEX POSEIDON; IGBP DISCOVER; MASS-BALANCE; WAVE-FORMS; SHEET AB The Ice, Cloud and Land Elevation Satellite (ICESat) mission will measure changes in elevation of the Greenland and Antarctic ice sheets as part of NASA's Earth Observing System (EOS) of satellites. Time-series of elevation changes will enable determination of the present-day mass balance of the ice sheets, study of associations between observed ice changes and polar climate, and estimation of the present and future contributions of the ice sheets to global sea level rise. Other scientific objectives of ICESat include: global measurements of cloud heights and the vertical structure of clouds and aerosols; precise measurements of land topography and vegetation canopy heights; and measurements of sea ice roughness, sea ice thickness, ocean surface elevations, and surface reflectivity. The Geoscience Laser Altimeter System (GLAS) on ICESat has a 1064 nm laser channel for surface altimetry and dense cloud heights and a 532 nm lidar channel for the vertical distribution of clouds and aerosols. The predicted accuracy for the surface-elevation measurements is 15 em, averaged over 60 m diameter laser footprints spaced at 172 m alongtrack. The orbital altitude will be around 600 km at an inclination of 94degrees with a 183-day repeat pattern. The on-board GPS receiver will enable radial orbit determinations to better than 5 cm, and star-trackers will enable footprints to be located to 6 m horizontally. The spacecraft attitude will be controlled to point the laser beam to within 35 m of reference surface tracks at high latitudes. ICESat is designed to operate for 3-5 years and should be followed by successive missions to measure ice changes for at least 75 years. (C) 2002 Published by Elsevier Science Ltd. C1 NASA, Goddard Space Flight Ctr, Earth Sci Directorate, Greenbelt, MD 20771 USA. Univ Texas, Space Res Ctr, Austin, TX 78722 USA. NASA Headquarters, Washington, DC USA. Univ Wisconsin, Dept Geol & Geophys, Madison, WI 53706 USA. NASA, Goddard Space Flight Ctr, Raytheon ITSS, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, ICESat Project Off, Greenbelt, MD 20771 USA. MIT, Cambridge, MA 02139 USA. Univ Calif San Diego, Scripps Inst Oceanog, La Jolla, CA 92093 USA. NASA, Goddard Space Flight Ctr, SSAI, Greenbelt, MD 20771 USA. NASA, Wallops Flight Facil, EG&G Inc, Wallops Isl, VA 23337 USA. RP Zwally, HJ (reprint author), NASA, Goddard Space Flight Ctr, Earth Sci Directorate, Code 900, Greenbelt, MD 20771 USA. RI Abshire, James/I-2800-2013; Harding, David/F-5913-2012 NR 93 TC 475 Z9 519 U1 10 U2 93 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0264-3707 J9 J GEODYN JI J. Geodyn. PD OCT-NOV PY 2002 VL 34 IS 3-4 BP 405 EP 445 AR PII S0264-3707(02)00042-X DI 10.1016/S0264-3707(02)00042-X PG 41 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 602BK UT WOS:000178484800006 ER PT J AU Luthcke, SB Carabajal, CC Rowlands, DD AF Luthcke, SB Carabajal, CC Rowlands, DD TI Enhanced geolocation of spaceborne laser altimeter surface returns: parameter calibration from the simultaneous reduction of altimeter range and navigation tracking data SO JOURNAL OF GEODYNAMICS LA English DT Article ID TOPEX/POSEIDON; TOPOGRAPHY; VEGETATION; ORBIT AB The accurate geolocation of a laser altimeter's surface return, the spot from which the laser energy reflects on the Earth's surface, is a critical issue in the scientific application of these data. Pointing, ranging, timing and orbit errors must be compensated to accurately geolocate these data. Detailed laser altimeter measurement models have been developed and implemented within precision orbit determination software providing the capability to simultaneously estimate the orbit and geolocation parameters from a combined reduction of altimeter range and spacecraft tracking data. In preparation for NASA's future dedicated Earth observing spaceborne laser altimeter missions, the Vegetation Canopy Lidar (VCL) and the Ice, Cloud and land Elevation Satellite (ICESat), data from two Shuttle Laser Altimeter (SLA) missions have been reprocessed to test and refine these algorithms and to develop the analysis methodologies for the production and verification of enhanced geolocation products. Both direct altimetry and dynamic crossover data have been reduced in combination with navigation tracking data to obtain significant improvement in SLA geolocation accuracy. Residual and overlap precision tests indicate a factor of two improvement over the previously released SLA Standard Data Products, showing 40-m RMS horizontal and 26-cm RMS elevation geolocation precision for the long SLA-01 arcs. Accuracy estimates by comparing SLA profiles to Digital Elevation Models show horizontal positioning accuracy at the 60-m (1sigma) level. Vertical accuracies, on the order of 1 m (1sigma) for low slope surfaces are now dominated by the +/- 75-cm one-way range resolution of the instrument. Comparable relative improvements are also observed in the analysis of the SLA-02 data. The analyses show that complex temporal variations in parameters (i.e., pointing) can be recovered and not just simple biases. The methodology and results obtained from the detailed analysis are discussed in this paper, along with their applicability to VCL and ICESat. Published by Elsevier Science Ltd. C1 NASA, Goddard Space Flight Ctr, Terr Phys Lab, Space Geodesy Branch, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, NVI Inc, Greenbelt, MD 20771 USA. RP Luthcke, SB (reprint author), NASA, Goddard Space Flight Ctr, Terr Phys Lab, Space Geodesy Branch, Code 926, Greenbelt, MD 20771 USA. RI Rowlands, David/D-2751-2012; Luthcke, Scott/D-6283-2012 NR 25 TC 10 Z9 10 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0264-3707 J9 J GEODYN JI J. Geodyn. PD OCT-NOV PY 2002 VL 34 IS 3-4 BP 447 EP 475 AR PII S0264-3707(02)00047-9 DI 10.1016/S0264-3707(02)00047-9 PG 29 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 602BK UT WOS:000178484800007 ER PT J AU Hofton, MA Blair, JB AF Hofton, MA Blair, JB TI Laser altimeter return pulse correlation: a method for detecting surface topographic change SO JOURNAL OF GEODYNAMICS LA English DT Article ID LONG-VALLEY; CALIFORNIA; ACCURACY AB Quantifying and monitoring of many natural hazards requires repeated measurements of a topographic surface whose change reflects a geological or geophysical process. Topography and topographic change measurements are routinely made using techniques such as Interferometric Synthetic Aperture Radar and GPS, but both of these techniques have limitations for these purposes. A technique attracting increasing attention for its ability to perform accurate high-resolution topographic mapping (including sub-canopy) is laser altimetry, or lidar. Here, we evaluate the feasibility of a new method for using laser altimeter return echoes, or waveforms, to detect relative elevation change. The method, dubbed the return pulse correlation method, maximizes the shape similarity of coincident laser return waveforms from two observation epochs by shifting them vertically. We evaluate the accuracy of the pulse correlation method using laser altimeter data acquired over the NASA Wallops Flight Facility, VA, a region where no elevation change is expected within the time period of the surveys, and at Assateague Island, MD, a highly dynamic barrier island where several meters of erosion and deposition have been observed. Results show that use of the pulse correlation method generates elevation change estimates similar in magnitude to those obtained by simply differencing coincident laser altimeter elevation measurements (dubbed the spot comparison method). Along the beach at Assateague Island, MD, similar patterns of accretion and deposition are detected using both the pulse correlation and spot comparison methods, although some horizontal resolution is lost using the pulse correlation method because of the wide footprint spacing of the waveform-recording laser altimeter used in the study. In the test case presented here, increasing the size of the laser footprint from 25 to 60 m caused the magnitude of the vertical change signal to be underestimated, confirming that the resolution of the measurement technique and the scale of the deformation features should be considered when planning survey missions. The use of this method can improve the accuracy of surface change estimates made using laser altimeter waveforms, especially beneath vegetation, by eliminating the subjective interpretation of waveforms used to extract a single elevation measurement. (C) Published by Elsevier Science Ltd. C1 Univ Maryland, Dept Geog, College Pk, MD 20742 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Hofton, MA (reprint author), Univ Maryland, Dept Geog, College Pk, MD 20742 USA. RI Blair, James/D-3881-2013; Beckley, Matthew/D-4547-2013 NR 17 TC 21 Z9 21 U1 3 U2 11 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0264-3707 J9 J GEODYN JI J. Geodyn. PD OCT-NOV PY 2002 VL 34 IS 3-4 BP 477 EP 489 AR PII S0264-3707(02)00043-1 DI 10.1016/S0264-3707(02)00043-1 PG 13 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 602BK UT WOS:000178484800008 ER PT J AU Hofton, MA Rocchio, LE Blair, JB Dubayah, R AF Hofton, MA Rocchio, LE Blair, JB Dubayah, R TI Validation of Vegetation Canopy Lidar sub-canopy topography measurements for a dense tropical forest SO JOURNAL OF GEODYNAMICS LA English DT Article ID LASER ALTIMETER; WAVE-FORMS; RESOLUTION; LAND AB Large footprint (greater than 10 m wide) laser altimetry is a useful technique for mapping topography (including sub-canopy), canopy height and vertical structure in densely vegetated areas. In March 1998, the Laser Vegetation Imaging Sensor (LVIS), an airborne laser altimeter, mapped a similar to800 km(2) area of Costa Rica including the La Selva Biological Station using 25 m-diameter footprints as part of the pre-launch activities of the Vegetation Canopy Lidar (VCL) Mission. To investigate the utility of the lidar technique for making sub-canopy topography measurements, the precision and accuracy of the LVIS elevation measurements from this mission are assessed. Crossover analysis using laser shots whose recorded waveforms contained more than 50% of the total returned energy within their lowest reflections show the elevations have a precision of better than 1 m. Comparison of the LVIS elevations with coincident in situ ground elevation data reveals that the measurements are within similar to1.5 m of each other on less than 3 slopes. All measurements are within similar to5 m of each other (on slopes of up to 30degrees). These are very encouraging results given that the forests of this region are some of the densest, most complex on Earth, and that snapping their sub-canopy topography are near-impossible using any other remote sensing technique. Given the similarity of the measurement processes of the LVIS and VCL systems, these results suggest that the topographic measurements made by the VCL will meet stated accuracy goals under the majority of measurement conditions. Published by Elsevier Science Ltd. C1 Univ Maryland, Dept Geog, College Pk, MD 20742 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Hofton, MA (reprint author), Univ Maryland, Dept Geog, College Pk, MD 20742 USA. RI Blair, James/D-3881-2013; Beckley, Matthew/D-4547-2013 NR 20 TC 56 Z9 57 U1 2 U2 17 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0264-3707 J9 J GEODYN JI J. Geodyn. PD OCT-NOV PY 2002 VL 34 IS 3-4 BP 491 EP 502 AR PII S0264-3707(02)00046-7 DI 10.1016/S0264-3707(02)00046-7 PG 12 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 602BK UT WOS:000178484800009 ER PT J AU Degnan, JJ AF Degnan, JJ TI Photon-counting multikilohertz microlaser altimeters for airborne and spaceborne topographic measurements SO JOURNAL OF GEODYNAMICS LA English DT Article ID LASER AB We consider the optimum design of photon-counting microlaser altimeters operating from airborne and spaceborne platforms under both day and night conditions. Extremely compact, passively Q-switched microlaser transmitters produce trains of low energy pulses at multi-kHz rates and can easily generate subnanosecond pulsewidths for precise ranging. To guide the design, we have modeled the solar noise background and developed simple algorithms, based on post-detection Poisson filtering (PDPF), to optimally extract the weak altimeter signal from a high noise background during daytime operations. The advantages of photon-counting detector arrays followed by multichannel timing receivers for high resolution topographic mapping are discussed. Practical technology issues, such as detector and/or receiver dead times and their impact on signal detection and ranging accuracy and resolution, have also been considered in the analysis. The theoretical results are reinforced by data from an airborne microlaser altimeter, developed under NASA's Instrument Incubator Program. The latter instrument has operated at several kHz rates from aircraft cruise altitudes up to 6.7 km with laser pulse energies on the order of a few microjoules. The instrument has successfully recorded decimeter accuracy or better single photon returns from man-made structures, tree canopies and underlying terrain and has demonstrated shallow water bathymetry at depths to a few meters. We conclude the discussion by analyzing a photon counting instrument designed to produce, over a mission life of 3 years, a globally contiguous map of the Martian surface, with 5 m horizontal resolution and decimeter vertical accuracy, from an altitude of 300 km. The transmitter power-receive aperture product required is comparable to the Geoscience Laser Altimeter System (GLAS) but the number of individual range measurements to the surface is increased by three to four orders of magnitude. For more modest scientific goals, on a par with the capabilities of conventional high SNR spaceborne altimeters, significantly more compact and power efficient instruments can be constructed through the use of photon-counting techniques. Published by Elsevier Science Ltd. C1 NASA, Goddard Space Flight Ctr, Geosci Technol Off, Greenbelt, MD 20771 USA. RP Degnan, JJ (reprint author), NASA, Goddard Space Flight Ctr, Geosci Technol Off, Code 920-3, Greenbelt, MD 20771 USA. NR 24 TC 60 Z9 63 U1 0 U2 11 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0264-3707 J9 J GEODYN JI J. Geodyn. PD OCT-NOV PY 2002 VL 34 IS 3-4 BP 503 EP 549 AR PII S0264-3707(02)00045-5 DI 10.1016/S0264-3707(02)00045-5 PG 47 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 602BK UT WOS:000178484800010 ER PT J AU Degnan, JJ AF Degnan, JJ TI Asynchronous laser transponders for precise interplanetary ranging and time transfer SO JOURNAL OF GEODYNAMICS LA English DT Article AB Satellite laser ranging (SLR) and lunar laser ranging (LLR) systems are single-ended instruments, i.e. they measure the roundtrip transit tune of a laser pulse to a passive optical reflector. Since such single-ended systems are incapable of ranging beyond the Moon to the planets, we consider the feasibility of a two-way asynchronous (i.e. independently firing) interplanetary laser transponder pair, capable of decimeter ranging and subnanosecond time transfer from Earth to a spacecraft anywhere within the inner Solar System. After introducing the transponder link equation and the concept of "balanced" transponders, we describe how range and time can be transferred between terminals, and preview the potential advantages of photon counting asynchronous transponders for interplanetary applications. We then develop mathematical models for the various sources of noise in an interplanetary transponder link including planetary albedo, solar or lunar illumination of the local atmosphere, and laser backscatter off the local atmosphere. After introducing the key engineering components of an interplanetary laser transponder, we develop an operational scenario for the acquisition and tracking of the opposite terminal. We then use the theoretical models of the previous sections to perform an Earth-Mars link analysis over a full synodic period of 780 days under the simplifying assumption of coaxial, coplanar, circular orbits. We demonstrate that, using slightly modified versions of existing space and ground based laser systems, an Earth-Mars transponder link is not only feasible but quite robust. We also demonstrate through analysis the potential advantages of compact, low output power (< 300 mW), photon-counting transponders, which utilize NASA's developmental SLR2000 satellite laser ranging system as the Earth terminal and offer some concluding remarks regarding future applications. Published by Elsevier Science Ltd. C1 NASA, Goddard Space Flight Ctr, Geosci Technol Off, Terr Phys Lab, Greenbelt, MD 20771 USA. RP Degnan, JJ (reprint author), NASA, Goddard Space Flight Ctr, Geosci Technol Off, Terr Phys Lab, Code 920-3, Greenbelt, MD 20771 USA. NR 21 TC 33 Z9 36 U1 1 U2 4 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0264-3707 J9 J GEODYN JI J. Geodyn. PD OCT-NOV PY 2002 VL 34 IS 3-4 BP 551 EP 594 AR PII S0264-3707(02)00044-3 DI 10.1016/S0264-3707(02)00044-3 PG 44 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 602BK UT WOS:000178484800011 ER PT J AU Bruinsma, S Lemoine, FG AF Bruinsma, S Lemoine, FG TI A preliminary semiempirical thermosphere model of Mars: DTM-Mars SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article DE Mars thermosphere; atmospheric drag; orbit determination ID SPECTROMETER TES OBSERVATIONS; SOLAR-CYCLE VARIATION; GLOBAL SURVEYOR; THERMAL STRUCTURE; ATMOSPHERE; TEMPERATURES; AEROBRAKING; VIKING; WINDS; DRAG AB A semiempirical thermosphere model of Mars has been constructed based on the DTM algorithm that was developed for the terrestrial thermosphere. DTM-Mars reproduces the observed densities with a 1-sigma model uncertainty of approximately 35% outside dust season. During dust storms the uncertainty increases by approximately a factor two. The data used in this study have been derived from the Mars Global Surveyor accelerometer observations as well as from analysis of precise orbit determination results. The temperature modeling is based on the Mars-GRAM 2000 [Justus and James, 2000] and the MTGCM [Bougher et al., 2000] models, while the CO(2), O, and He constituent modeling has been achieved through the adjustment of model coefficients to density data. DTM-Mars is preliminary because the geographical and solar activity coverage of the assimilated density data currently available is not representative of all atmospheric conditions. For example, the effect of dust storms on the thermospheric density is only represented by a temperature increase on a planetary scale, because the data did not allow the determination of a semidiurnal variation caused by local effects in the lower atmosphere. The model accuracy will be improved in the future by assimilating density data taken under different atmospheric conditions, for example, from the Mars Odyssey mission, once these become available. C1 CNES, Dept Terr & Planetary Geodesy, F-31401 Toulouse 4, France. NASA, Goddard Space Flight Ctr, Terr Phys Lab, Greenbelt, MD 20771 USA. RP Bruinsma, S (reprint author), CNES, Dept Terr & Planetary Geodesy, 18 Ave E Belin, F-31401 Toulouse 4, France. EM sean.bruinsma@cnes.fr RI Lemoine, Frank/D-1215-2013 NR 27 TC 12 Z9 12 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD OCT PY 2002 VL 107 IS E10 AR 5085 DI 10.1029/2001JE001508 PG 13 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 639MW UT WOS:000180634100015 ER PT J AU Johnson, JR Horz, F Lucey, PG Christensen, PR AF Johnson, JR Horz, F Lucey, PG Christensen, PR TI Thermal infrared spectroscopy of experimentally shocked anorthosite and pyroxenite: Implications for remote sensing of Mars SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Review DE anorthosite; pyroxenite; shock; spectra; thermal infrared; remote sensing; Mars ID EMISSION-SPECTROSCOPY; HIGH-PRESSURE; REFLECTANCE SPECTRA; MARTIAN SURFACE; MU-M; PLAGIOCLASE FELDSPARS; RAMAN-SPECTROSCOPY; PLANETARY SURFACES; STILLWATER-COMPLEX; DIAPLECTIC GLASS AB The feldspar and pyroxene mineralogies on Mars revealed by the Thermal Emission Spectrometer (TES) on Mars Global Surveyor likely record a variety of shock effects, as suggested by petrologic analyses of the Martian meteorites and the abundance of impact craters on the planet's surface. To study the effects of shock pressures on thermal infrared spectra of these minerals, we performed shock recovery experiments on orthopyroxenite and anorthosite samples from the Stillwater Complex (Montana) over peak pressures from 17 to 63 GPa. We acquired emissivity and hemispherical reflectance spectra (350-1400 cm(-1); similar to7-29 mum) of both coherent chips and fine-grained powders of shocked and unshocked samples. These spectra are more directly comparable to remotely sensed data of Mars (e.g., TES) than previously acquired absorption or transmission spectra of shocked minerals. The spectra of experimentally shocked feldspar show systematic changes with increasing pressure due to depolymerization of the silica tetrahedra. For the spectra of chips, this includes the disappearance of small bands in the 500-650 cm(-1) region and a strong band at 1115 cm(-1), and changes in positions of a strong band near 940 cm(-1) and the Christiansen feature near 1250 cm(-1). Spectra of the shocked powders show the gradual disappearance of a transparency feature near 830 cm(-1). Fewer changes are observed in the pyroxene spectra at pressures as high as 63 GPa. Spectra of experimentally shocked minerals will help identify more precisely the mineralogy of rocks and soils not only from TES but also from Mars instruments such as miniTES and THEMIS. C1 US Geol Survey, Flagstaff, AZ 86001 USA. Arizona State Univ, Dept Geol, Tempe, AZ 85287 USA. Lyndon B Johnson Space Ctr, Houston, TX USA. Univ Hawaii, Hawaii Inst Geophys & Planetol, Honolulu, HI 96822 USA. RP Johnson, JR (reprint author), US Geol Survey, 2255 N Gemini Dr, Flagstaff, AZ 86001 USA. EM jrjohnson@usgs.gov RI Johnson, Jeffrey/F-3972-2015 NR 118 TC 38 Z9 38 U1 2 U2 10 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9097 EI 2169-9100 J9 J GEOPHYS RES-PLANET JI J. Geophys. Res.-Planets PD OCT PY 2002 VL 107 IS E10 AR 5073 DI 10.1029/2001JE001517 PG 14 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 639MW UT WOS:000180634100003 ER PT J AU Melbourne, TI Webb, FH Stock, JM Reigber, C AF Melbourne, TI Webb, FH Stock, JM Reigber, C TI Rapid postseismic transients in subduction zones from continuous GPS SO JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH LA English DT Article DE subduction zone; earthquake; postseismic; moment release ID 1995 COLIMA-JALISCO; 28 JUNE 1992; STRAIN ACCUMULATION; FAULT-SLIP; LANDERS EARTHQUAKE; CHILE EARTHQUAKE; SOUTHWEST JAPAN; RUPTURE PROCESS; OKI EARTHQUAKE; NAZCA PLATE AB [1] Continuous GPS time series from three of four recently measured, large subduction earthquakes document triggered rapid postseismic fault creep, representing an additional moment release upward of 25% over the weeks following their main shocks. Data from two M-w = 8.0 and M-w = 8.4 events constrain the postseismic centroids to lie down dip from the lower limit of coseismic faulting, and show that afterslip along the primary coseismic asperities is significantly less important than triggered deep creep. Time series for another M-w = 7.7 event show 30% postseismic energy release, but here we cannot differentiate between afterslip and triggered deeper creep. A fourth M-w = 8.1 event, which occurred in the broad Chilean seismogenic zone, shows no postseismic deformation, despite coseismic offsets in excess of 1 m. For the three events which are followed by postseismic deformation, stress transferred to the inferred centroids (at 34, 60, and 36 km depths) by their respective main shock asperities increased reverse shear stress by 0.5, 0.8, and 0.2 bar with a comparatively small decrease in normal stress (0.01 bar), constraining the Coulomb stress increase required to force slip along the metastable plate interface. Deep triggered slip of this nature is invisible without continuous geodesy but on the basis of these earthquakes would appear to constitute an important mode of strain release from beneath the seismogenic zones of convergent margins. These events, captured by some of the first permanent GPS networks, show that deep moment release is often modulated by seismogenic rupture updip and underscore the need for continuous geodesy to fully quantify the spectrum of moment release in great earthquakes. C1 Cent Washington Univ, Dept Geol Sci, Ellensburg, WA 98926 USA. CALTECH, Seismol Lab, Pasadena, CA 91125 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Geoforschungszentrum Potsdam, D-14473 Potsdam, Germany. RP Melbourne, TI (reprint author), Cent Washington Univ, Dept Geol Sci, Ellensburg, WA 98926 USA. EM tim@geology.cwu.edu; jstock@gps.caltech.edu OI Stock, Joann Miriam/0000-0003-4816-7865 NR 77 TC 67 Z9 70 U1 0 U2 8 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9313 EI 2169-9356 J9 J GEOPHYS RES-SOL EA JI J. Geophys. Res.-Solid Earth PD OCT PY 2002 VL 107 IS B10 AR 2241 DI 10.1029/2001JB000555 PG 10 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 637RC UT WOS:000180525500035 ER PT J AU Boberg, F Lundstedt, H Hoeksema, JT Scherrer, PH Liu, W AF Boberg, F Lundstedt, H Hoeksema, JT Scherrer, PH Liu, W TI Solar mean magnetic field variability: A wavelet approach to Wilcox Solar Observatory and SOHO/Michelson Doppler Imager observations SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article DE solar magnetic field; wavelet analysis; internal rotation; active regions; coronal mass ejections ID CORONAL MASS EJECTIONS; SUN; PREDICTION; CYCLE; SOHO AB [1] Solar mean magnetic field (SMMF) measurements from the Wilcox Solar Observatory and with the SOHO/MDI instrument are described and analyzed. Even though two completely different methods of observation are used, the two data sets obtained show a strong similarity. Using continuous wavelet transforms, SMMF variability is found at a number of temporal scales. Detected SMMF signals with a 1-2 year period are considered to be linked to variations in the internal rotation of the Sun. Intermediate SMMF oscillations with a period of 80-200 days are probably connected to the evolution of large active regions. We also find evidence for 90 min variations with coronal mass ejections as a suggested origin. C1 Lund Observ, SE-22100 Lund, Sweden. NASA Headquarters, Off Space Sci, Res Program Management Div, Washington, DC 20546 USA. Swedish Inst Space Phys, Solar Terr Phys Div, SE-22370 Lund, Sweden. Stanford Univ, WW Hansen Expt Phys Lab, Stanford, CA 94305 USA. RP Boberg, F (reprint author), Lund Observ, Box 43, SE-22100 Lund, Sweden. EM fredrik@astro.lu.se; henrik@irfl.lu.se; todd.hoeksema@hq.nasa.gov; pscherrer@solar.stanford.edu; wliu@solar.stanford.edu NR 31 TC 14 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-SPACE JI J. Geophys. Res-Space Phys. PD OCT PY 2002 VL 107 IS A10 AR 1318 DI 10.1029/2001JA009195 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 634RF UT WOS:000180353900053 ER PT J AU Burlaga, LF Richardson, JD Wang, C AF Burlaga, LF Richardson, JD Wang, C TI Speed fluctuations near 60 AU on scales from 1 day to 1 year: Observations and model SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article DE solar wind speed; speed fluctuations; distant heliosphere ID PRESSURE-BALANCED STRUCTURES; SOLAR-WIND; OUTER HELIOSPHERE; PICKUP PROTONS; VOYAGER-2 OBSERVATIONS; INTERACTION REGIONS; MAGNETIC-FIELD; TURBULENCE; DENSITY; INTERMITTENCY AB [1] This paper describes the multiscale, statistical state of the speed observed near 60 AU from mid-1999 to mid-2000 by Voyager 2 (V2), and it shows that a multifluid MHD model can explain the basic features of these observations. The probability distribution functions (PDFs) of the running speed differences (dVn) on scales from 1 day to 256 days provide a relatively complete description of some important properties of the large-scale speed fluctuations. On a scale of 1 or 2 days the PDFs of the positive and negative speed differences observed by V2 are approximately exponential, which is related to jump-ramp structures but might include a contribution from intermittent turbulence. On scales greater than 26 days (the solar rotation period) the PDFs of the speed differences are approximately Gaussian, i.e., quadratic on a semilog scale. On a scale of the order of several days, on which one sees jump-ramp structures in the speed profile, the PDF of the speed differences is cubic on a semilog scale. The standard deviation of dVn increases with increasing scale. The skewness and kurtosis of dVn are relatively large at small scales and decrease to Gaussian values at scales greater than or equal to16 days. The PDFs of speed differences and their lower moments versus scale near 60 AU were also derived from a speed profile predicted by the deterministic, spherically symmetric, multifluid, MHD model of Chi Wang, using ACE observations at 1 AU as the inner boundary conditions. Although the projected speed profile is not the same as the observed speed profile because ACE and Voyager are not radially aligned throughout the 1-year interval, the statistical properties of the observed profiles are essentially the same as the projected speed profiles. Significant evolution of the multiscale statistical properties of the solar wind speed fluctuations occurs between 1 and 60 AU; this evolution can be explained by a deterministic model. C1 NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. MIT, Ctr Space Res, Cambridge, MA 02139 USA. Chinese Acad Sci, Lab Space Weather, Beijing, Peoples R China. RP Burlaga, LF (reprint author), NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Mail Code 692,Bldg 2,Room 127, Greenbelt, MD 20771 USA. NR 48 TC 3 Z9 3 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 OCT PY 2002 VL 107 IS A10 AR 1328 DI 10.1029/2002JA009379 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 634RF UT WOS:000180353900063 ER PT J AU Burlaga, LF Plunkett, SP St Cyr, OC AF Burlaga, LF Plunkett, SP St Cyr, OC TI Successive CMEs and complex ejecta SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article DE ejecta; CMEs; magnetic field; solar wind ID CORONAL MASS EJECTIONS; SOLAR-WIND; MAGNETIC CLOUDS; GEOMAGNETIC STORMS; LASCO OBSERVATIONS; COMPOUND STREAMS; ACE; EVOLUTION; FIELDS; FLOWS AB [1] We identified three sets of successive halo CMEs directed toward Earth (two or more CMEs observed within 1- 4 days in the corona) and the corresponding flows and magnetic fields at 1 AU. Each set of successive halo CMEs was associated with complex ejecta at 1 AU. Complex ejecta were defined by Burlaga et al. [2001] as fast (> 600 km/ s) flows that are neither corotating flows nor magnetic clouds, which move past Earth during a day or more. They correspond to the transient flows discussed in the literature prior to the discovery of magnetic clouds. We infer that in each case the successive CMEs merged en route from the Sun to the Earth to form complex ejecta. In general, the components of the complex ejecta corresponding to individual CMEs cannot be identified, suggesting that the merging process is nonlinear and irreversible, and memory of the conditions near the sun is lost in the process. The identity of the individual CMEs is gradually lost as the interaction proceeds within 1 AU. In some cases, the interaction can result in what appears to be a single stream in the speed profile at 1 AU. Nevertheless, given observations of successive halo CMEs, one can possibly predict the arrival of complex ejecta or more complicated transient flow systems at 1 AU. In some cases, complex ejecta related to multiple CMEs can be associated with a single source region, an active region. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Catholic Univ Amer, Dept Phys, Washington, DC 20064 USA. USN, Res Lab, Univ Space Res Assoc, Washington, DC 20375 USA. RP Burlaga, LF (reprint author), NASA, Goddard Space Flight Ctr, Code 692, Greenbelt, MD 20771 USA. NR 48 TC 81 Z9 84 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 OCT PY 2002 VL 107 IS A10 AR 1266 DI 10.1029/2001JA000255 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 634RF UT WOS:000180353900001 ER EF