FN Thomson Reuters Web of Science™ VR 1.0 PT J AU Meyer, TE Tsapin, AI Vandenberghe, I De Smet, L Frishman, D Nealson, KH Cusanovich, MA Van Beeumen, JJ AF Meyer, TE Tsapin, AI Vandenberghe, I De Smet, L Frishman, D Nealson, KH Cusanovich, MA Van Beeumen, JJ TI Identification of 42 possible cytochrome c genes in the Shewanella oneidensis genome and characterization of six soluble cytochromes SO OMICS-A JOURNAL OF INTEGRATIVE BIOLOGY LA English DT Article ID OUTER-MEMBRANE CYTOCHROMES; PUTREFACIENS NCIMB 400; ESCHERICHIA-COLI K-12; FUMARATE REDUCTASE; FLAVOCYTOCHROME-C; TRANSCRIPTIONAL REGULATION; WOLINELLA-SUCCINOGENES; PSEUDOMONAS-AERUGINOSA; ANAEROBIC RESPIRATION; PROTEOMIC ANALYSIS AB Through pattern matching of the cytochrome c heme-binding site (CXXCH) against the genome sequence of Shewanella oneidensis MR-1, we identified 42 possible cytochrome c genes (27 of which should be soluble) out of a total of 4758. However, we found only six soluble cytochromes c in extracts of S. oneidensis grown under several different conditions: (1) a small tetraheme cytochrome c, (2) a tetraheme flavocytochrome c-fumarate reductase, (3) a diheme cytochrome c(4), (4) a monoheme cytochrome c(5), (5) a monoheme cytochrome c', and (6) a diheme bacterial cytochrome c peroxidase. These cytochromes were identified either through N-terminal or complete amino acid sequence determination combined with mass spectroscopy. All six cytochromes were about 10-fold more abundant when cells were grown at low than at high aeration, whereas the flavocytochrome c-fumarate reductase was specifically induced by anaerobic growth on fumarate. When adjusted for the different heme content, the monoheme cytochrome c(5) is as abundant as are the small tetraheme, cytochrome and the tetraheme fumarate reductase. Published results on regulation of cytochromes from DNA microarrays and 2D-PAGE differ somewhat from our results, emphasizing the importance of multifaceted analyses in proteomics. C1 Univ Arizona, Dept Biochem & Mol Biophys, Tucson, AZ 85721 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. State Univ Ghent, Dept Biochem Physiol & Microbiol, Lab Prot Biochem & Prot Engn, B-9000 Ghent, Belgium. Tech Univ Munich, D-8050 Freising Weihenstephan, Germany. Univ So Calif, Dept Earth Sci, Los Angeles, CA USA. RP Meyer, TE (reprint author), Univ Arizona, Dept Biochem & Mol Biophys, Tucson, AZ 85721 USA. EM temeyer@u.arizona.edu RI De Smet, Lina/A-7354-2013 FU NIGMS NIH HHS [GM21277] NR 58 TC 104 Z9 106 U1 6 U2 23 PU MARY ANN LIEBERT INC PUBL PI LARCHMONT PA 2 MADISON AVENUE, LARCHMONT, NY 10538 USA SN 1536-2310 J9 OMICS JI OMICS PD SPR PY 2004 VL 8 IS 1 BP 57 EP 77 DI 10.1089/153623104773547499 PG 21 WC Biotechnology & Applied Microbiology; Genetics & Heredity SC Biotechnology & Applied Microbiology; Genetics & Heredity GA 832CO UT WOS:000222245000006 PM 15107237 ER PT J AU Gappinger, RO Greivenkamp, JE Borman, C AF Gappinger, RO Greivenkamp, JE Borman, C TI High-modulation camera for use with a non-null interferometer SO OPTICAL ENGINEERING LA English DT Article DE sparse array sensor; non-null interferometer; subNyquist interferometry; high-frequency detector; modulation transfer function testing; aliasing AB High-frequency fringe patterns found in non-null interferometric testing of aspheres require the use of special detector arrays containing small, widely spaced pixels. A sparse array camera with the ability to detect high spatial frequencies has been developed. The modulation transfer function (MTF) of the camera is measured using a sinusoidal fringe pattern generated by a Mach-Zehnder interferometer. Spatial frequencies up to 400 cycles/mm are generated and used to characterize the MTF of the camera. (C) 2004 Society of Photo-Optical Instrumentation Engineers. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Arizona, Ctr Opt Sci, Tucson, AZ 85721 USA. CIDTEC Cameras & Imagers, Spectra Phys, Liverpool, NY 13088 USA. RP Gappinger, RO (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,M-S 306-388, Pasadena, CA 91109 USA. EM greiven@u.arizona.edu NR 9 TC 4 Z9 4 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 MAR PY 2004 VL 43 IS 3 BP 689 EP 696 DI 10.1117/1.1645258 PG 8 WC Optics SC Optics GA 808EM UT WOS:000220552400021 ER PT J AU Tai, AT Sanders, WH Alkalai, L Chau, SN Tso, KS AF Tai, AT Sanders, WH Alkalai, L Chau, SN Tso, KS TI Performability analysis of guarded-operation duration: a translation approach for reward model solutions SO PERFORMANCE EVALUATION LA English DT Article; Proceedings Paper CT International Performance and Dependability Symposium CY 2002 CL Washington, DC DE performability; reduction of total performance degradation; duration of guarded operation; reward model solutions; model translation; stochastic activity networks ID RELIABILITY; RECOVERY AB Performability measures are often defined for analyzing the worth of fault-tolerant systems whose performance is gracefully degradable. Accordingly, performability evaluation is inherently well suited for application of reward model solution techniques. On the other hand, the complexity of performability evaluation for solving engineering problems may prevent us from utilizing those techniques directly, suggesting the need for approaches that would enable us to exploit reward model solution techniques through problem transformation. In this paper, we present a performability modeling effort that analyzes the guarded-operation duration for onboard software upgrading. More specifically, we define a "perform ability index" Y that quantifies the extent to which the guarded operation with a duration phi reduces the expected total performance degradation. In order to solve for Y, we progressively translate its formulation until it becomes an aggregate of constituent measures conducive to efficient reward model solutions. Based on the reward-mapping-enabled intermediate model, we specify reward structures in the composite base model which is built on three stochastic activity network reward models. We describe the model-translation approach and show its feasibility for design-oriented performability modeling. (C) 2003 Elsevier B.V. All rights reserved. C1 IA Tech Inc, Los Angeles, CA 90024 USA. Univ Illinois, Urbana, IL 61801 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP IA Tech Inc, 10501 Kinnard Ave, Los Angeles, CA 90024 USA. EM a.t.tai@ieee.org; whs@crbc.uiuc.edu; lalkalai@jpl.nasa.gov; schau@jpl.nasa.gov; k.tso@ieee.org NR 20 TC 1 Z9 1 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0166-5316 EI 1872-745X J9 PERFORM EVALUATION JI Perform. Eval. PD MAR PY 2004 VL 56 IS 1-4 BP 249 EP 276 DI 10.1016/S0166-5316(03)00138-X PG 28 WC Computer Science, Hardware & Architecture; Computer Science, Theory & Methods SC Computer Science GA 777YH UT WOS:000189211100012 ER PT J AU Tucker, CJ Grant, DM Dykstra, JD AF Tucker, CJ Grant, DM Dykstra, JD TI NASA's global orthorectified landsat data set SO PHOTOGRAMMETRIC ENGINEERING AND REMOTE SENSING LA English DT Article ID VEGETATION; COVER AB NASA has sponsored the creation of an orthorectified and geodetically accurate global land data set of Landsat Multispectral Scanner, Thematic Mapper, and Enhanced Thematic Mapper data, from the 1970s, circa 1990, and circa 2000, respectively, to support a variety of scientific studies and educational purposes. This is the first time a geodetically accurate global compendium of orthorectified multi-epoch digital satellite data at the 30- to 80-m spatial scale spanning 30 years has been Produced for use by the international scientific and educational communities. We describe data selection, orthorectification, accuracy, access, and other aspects of these data. C1 NASA, Goddard Space Flight Ctr, Terr Phys Lab, Greenbelt, MD 20771 USA. Earth Satellite Corp, Rockville, MD 20852 USA. RP Tucker, CJ (reprint author), NASA, Goddard Space Flight Ctr, Terr Phys Lab, Code 661, Greenbelt, MD 20771 USA. EM compton@ltpmailx.gsfc.nasa.gov NR 20 TC 274 Z9 289 U1 6 U2 18 PU AMER SOC PHOTOGRAMMETRY PI BETHESDA PA 5410 GROSVENOR LANE SUITE 210, BETHESDA, MD 20814-2160 USA SN 0099-1112 J9 PHOTOGRAMM ENG REM S JI Photogramm. Eng. Remote Sens. PD MAR PY 2004 VL 70 IS 3 BP 313 EP 322 PG 10 WC Geography, Physical; Geosciences, Multidisciplinary; Remote Sensing; Imaging Science & Photographic Technology SC Physical Geography; Geology; Remote Sensing; Imaging Science & Photographic Technology GA 820QA UT WOS:000221403200006 ER PT J AU Bhatia, AK AF Bhatia, AK TI Electron-hydrogen P-wave elastic scattering SO PHYSICAL REVIEW A LA English DT Article AB In previous papers [ A. K. Bhatia and A. Temkin, Phys. Rev. A64, 032709 (2001) ; A. K. Bhatia, Phys. Rev. Aibid. 66, 064702 (2002) ], electron-hydrogen and electron- He+ S-wave scattering phase shifts were calculated using the optical potential approach. This method is now extended to the singlet and triplet electron-hydrogen P-wave scattering in the elastic region. Phase shifts are calculated using Hylleraas-type correlation functions with up to 220 terms. Results are rigorous lower bounds to the exact phase shifts and they are compared to phase shifts obtained from previous calculations. 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 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 MAR PY 2004 VL 69 IS 3 AR 032714 DI 10.1103/PhysRevA.69.032714 PG 4 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 808YU UT WOS:000220605200067 ER PT J AU Vatan, F Williams, C AF Vatan, F Williams, C TI Optimal quantum circuits for general two-qubit gates SO PHYSICAL REVIEW A LA English DT Article ID ENTANGLEMENT; OPERATIONS AB In order to demonstrate nontrivial quantum computations experimentally, such as the synthesis of arbitrary entangled states, it will be useful to understand how to decompose a desired quantum computation into the shortest possible sequence of one-qubit and two-qubit gates. We contribute to this effort by providing a method to construct an optimal quantum circuit for a general two-qubit gate that requires at most 3 controlled-NOT (CNOT) gates and 15 elementary one-qubit gates. Moreover, if the desired two-qubit gate corresponds to a purely real unitary transformation, we provide a construction that requries at most 2 CNOT and 12 one-qubit gates. We then prove that these constructions are optimal with respect to the family of CNOT, y-rotation, z-rotation, and phase gates. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Vatan, F (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM Farrokh.Vatan@jpl.nasa.gov; Colin.P.Williams@jpl.nasa.gov NR 18 TC 77 Z9 80 U1 0 U2 2 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1050-2947 J9 PHYS REV A JI Phys. Rev. A PD MAR PY 2004 VL 69 IS 3 AR 032315 DI 10.1103/PhysRevA.69.032315 PG 5 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 808YU UT WOS:000220605200045 ER PT J AU Boykin, TB Klimeck, G Oyafuso, F AF Boykin, TB Klimeck, G Oyafuso, F TI Valence band effective-mass expressions in the sp(3)d(5)s(*) empirical tight-binding model applied to a Si and Ge parametrization SO PHYSICAL REVIEW B LA English DT Article ID SPIN-ORBIT; SEMICONDUCTORS; PARAMETERS; SIMULATIONS; TRANSPORT AB Exact, analytic expressions for the valence band effective masses in the spin-orbit, sp(3)d(5)s(*) empirical tight-binding model are derived. These expressions together with an automated fitting algorithm are used to produce improved parameter sets for Si and Ge at room temperature. Detailed examinations of the analytic effective-mass expressions reveal critical capabilities and limitations of this model in reproducing simultaneously certain gaps and effective masses. The [110] masses are shown to be completely determined by the [100] and [111] masses despite the introduction of d orbitals into the basis. C1 Univ Alabama, Dept Elect & Comp Engn, Huntsville, AL 35899 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Boykin, TB (reprint author), Univ Alabama, Dept Elect & Comp Engn, Huntsville, AL 35899 USA. RI Klimeck, Gerhard/A-1414-2012 OI Klimeck, Gerhard/0000-0001-7128-773X NR 21 TC 237 Z9 237 U1 0 U2 11 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 J9 PHYS REV B JI Phys. Rev. B PD MAR PY 2004 VL 69 IS 11 AR 115201 DI 10.1103/PhysRevB.69.115201 PG 10 WC Physics, Condensed Matter SC Physics GA 812BC UT WOS:000220814000059 ER PT J AU Yamada, T AF Yamada, T TI Modeling of carbon nanotube Schottky barrier modulation under oxidizing conditions SO PHYSICAL REVIEW B LA English DT Article ID FIELD-EFFECT TRANSISTORS; OXYGEN-ADSORPTION; LOGIC GATES; SINGLE; TRANSPORT; GRAPHITE; CLUSTERS; SYSTEMS; SURFACE; STATES AB A model is proposed for the previously reported lower Schottky barrier Phi(Bh) for hole transport in air than in vacuum at a junction between the metallic electrode and semiconducting carbon nanotube (CNT). We consider the electrostatics in a transition region between the electrode and CNT in the presence or absence of oxygen molecules (air or vacuum), where an appreciable potential drop occurs. The role of oxygen molecules is to increase this potential drop with a negative oxygen charge, leading to lower Phi(Bh) in air. The Schottky barrier modulation is large when a CNT depletion mode is involved, while the modulation is negligible when a CNT accumulation mode is involved. The mechanism prevails in both p- and n-CNT's, and the model consistently explains the key experimental findings. C1 NASA, Ames Res Ctr Nanotechnol, Moffett Field, CA 94035 USA. NASA, UARC, Moffett Field, CA 94035 USA. RP Yamada, T (reprint author), NASA, Ames Res Ctr Nanotechnol, M-S 229-1, Moffett Field, CA 94035 USA. EM yamada@nas.nasa.gov RI Yamada, Toshishige/E-7834-2012 OI Yamada, Toshishige/0000-0001-7145-9212 NR 42 TC 51 Z9 51 U1 1 U2 11 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 1098-0121 J9 PHYS REV B JI Phys. Rev. B PD MAR PY 2004 VL 69 IS 12 AR 125408 DI 10.1103/PhysRevB.69.125408 PG 8 WC Physics, Condensed Matter SC Physics GA 818QG UT WOS:000221259000115 ER PT J AU Ritchie, B Bhatia, AK AF Ritchie, B Bhatia, AK TI Phase-amplitude solution of the Schrodinger equation with application to free-free absorption SO PHYSICAL REVIEW E LA English DT Article ID QUANTUM HYDRODYNAMIC EQUATIONS; STOPPING POWER; COEFFICIENT; PLASMA; MOTION; ION AB The phase-amplitude method for solving the Schrodinger equation is implemented for free-free absorption in a hot, dense plasma. The method is benchmarked against two independent direct Schrodinger calculations. C1 Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Solar Phys Branch, Greenbelt, MD 20771 USA. RP Ritchie, B (reprint author), Lawrence Livermore Natl Lab, Livermore, CA 94550 USA. NR 19 TC 0 Z9 0 U1 1 U2 1 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 MAR PY 2004 VL 69 IS 3 AR 035402 DI 10.1103/PhysRevE.69.035402 PN 2 PG 3 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA 810UO UT WOS:000220729400008 ER PT J AU Pirozzoli, S Grasso, F Gatski, TB AF Pirozzoli, S Grasso, F Gatski, TB TI Direct numerical simulation and analysis of a spatially evolving supersonic turbulent boundary layer at M=2.25 SO PHYSICS OF FLUIDS LA English DT Article ID EFFICIENT IMPLEMENTATION; SCHEMES; FLOWS AB A spatially developing supersonic adiabatic flat plate boundary layer flow (at M-infinity=2.25 and Re(theta)approximate to4000) is analyzed by means of direct numerical simulation. The numerical algorithm is based on a mixed weighted essentially nonoscillatory compact-difference method for the three-dimensional Navier-Stokes equations. The main objectives are to assess the validity of Morkovin's hypothesis and Reynolds analogies, and to analyze the controlling mechanisms for turbulence production, dissipation, and transport. The results show that the essential dynamics of the investigated turbulent supersonic boundary layer flow closely resembles the incompressible pattern. The Van Driest transformed mean velocity obeys the incompressible law-of-the-wall, and the mean static temperature field exhibits a quadratic dependency upon the mean velocity, as predicted by the Crocco-Busemann relation. The total temperature has been found not to be precisely uniform, and total temperature fluctuations are found to be non-negligible. Consistently, the turbulent Prandtl number is not unity, and it varies between 0.7 and 0.8 in the outer part of the boundary layer. Nonetheless, a modified strong Reynolds analogy is still verified. In agreement with the low Mach number results, the streamwise velocity component and the temperature are only weakly anti-correlated. The turbulent kinetic energy budget also shows similarities with the incompressible case provided all terms of the equation are properly scaled; indeed, the leading compressibility contributions are negligible throughout the boundary layer. (C) 2004 American Institute of Physics. C1 Univ Roma La Sapienza, Dipartimento Meccan & Aeronaut, I-00184 Rome, Italy. NASA, Langley Res Ctr, Computat Modeling & Simulat Branch, Hampton, VA 23681 USA. RP Pirozzoli, S (reprint author), Univ Roma La Sapienza, Dipartimento Meccan & Aeronaut, Via Eudossiana 18, I-00184 Rome, Italy. NR 23 TC 105 Z9 121 U1 2 U2 29 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 MAR PY 2004 VL 16 IS 3 BP 530 EP 545 DI 10.1063/1.1637604 PG 16 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA 772WD UT WOS:000188864200003 ER PT J AU Kegerise, MA Spina, EF Garg, S Cattafesta, LN AF Kegerise, MA Spina, EF Garg, S Cattafesta, LN TI Mode-switching and nonlinear effects in compressible flow over a cavity SO PHYSICS OF FLUIDS LA English DT Article ID WAVELET TRANSFORM; SHEAR LAYERS; OSCILLATIONS AB Multiple distinct peaks of comparable strength in unsteady pressure autospectra often characterize compressible flow-induced cavity oscillations. It is unclear whether these different large-amplitude tones (i.e., Rossiter modes) coexist or are the result of a mode-switching phenomenon. The cause of additional peaks in the spectrum, particularly at low frequency, is also unknown. This article describes the analyses of unsteady pressure data in a cavity using time-frequency methods, namely the short-time Fourier transform (STFT) and the continuous Morlet wavelet transform, and higher-order spectral techniques. The STFT and wavelet analyses clearly show that the dominant mode switches between the primary Rossiter modes. This is verified by instantaneous schlieren images acquired simultaneously with the unsteady pressures. Furthermore, the Rossiter modes experience some degree of low-frequency amplitude modulation. An estimate of the modulation frequency, obtained from the wavelet analysis, matches the low-frequency peak seen in the autospectrum. Higher-order spectral methods were employed to investigate potential quadratic nonlinear interactions between the Rossiter modes and to determine if they are responsible for the low-frequency mode present in the autospectrum. In turn, this low-frequency mode could interact with the Rossiter modes to modulate their amplitude. Significant nonlinearities, in the form of sum and difference frequencies of the Rossiter modes, are present in the l/d=2 cavity at M-infinity=0.4, while nonlinear effects are much smaller in the l/d=4 at M-infinity=0.6. The bispectral analysis indicates that quadratic interactions between Rossiter modes in the near-field pressure are not responsible for the observed low-frequency peak in the pressure autospectrum. Furthermore, the low-frequency mode does not exhibit a strong nonlinear coupling with the Rossiter modes. (C) 2004 American Institute of Physics. C1 Syracuse Univ, Dept Mech Aerosp & Mfg Engn, Syracuse, NY 13244 USA. High Technol Corp, Hampton, VA 23666 USA. RP Kegerise, MA (reprint author), NASA, Langley Res Ctr, 1A E Reid St,Mail Stop 170, Hampton, VA 23681 USA. EM michael.a.kegerise@nasa.gov; catman@mae.ufl.edu RI Cattafesta, Louis/A-9545-2015 OI Cattafesta, Louis/0000-0002-5767-3383 NR 21 TC 60 Z9 60 U1 1 U2 9 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 1070-6631 J9 PHYS FLUIDS JI Phys. Fluids PD MAR PY 2004 VL 16 IS 3 BP 678 EP 687 DI 10.1063/1.1643736 PG 10 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA 772WD UT WOS:000188864200017 ER PT J AU De Freitas, N Dearden, R Hutter, F Morales-Menendez, R Mutch, J Poole, D AF De Freitas, N Dearden, R Hutter, F Morales-Menendez, R Mutch, J Poole, D TI Diagnosis by a waiter and a Mars explorer SO PROCEEDINGS OF THE IEEE LA English DT Article DE diagnosis; Rao-Blackwellized particle filtering; robotics; state estimation ID MODELS AB This paper shows how state-of-the-art state estimation techniques can be used to provide efficient solutions to the difficult problem of real-time diagnosis in mobile robots. The power of the adopted estimation techniques resides in our ability to combine particle filters with classical algorithms, such as Kalman filters. We demonstrate these techniques in two scenarios: a mobile waiter robot and planetary rovers designed by NASA for Mars exploration. C1 Univ British Columbia, Dept Comp Sci, Vancouver, BC V6T 1Z4, Canada. NASA, Ames Res Ctr, Adv Comp Sci Res Inst, Moffett Field, CA 94035 USA. Tech Univ Darmstadt, Dept Comp Sci, Intellect Grp, D-64283 Darmstadt, Germany. Univ British Columbia, Dept Comp Sci, Vancouver, BC V6T 1Z4, Canada. RP Univ British Columbia, Dept Comp Sci, Vancouver, BC V6T 1Z4, Canada. RI Morales-Menendez, Ruben/F-7181-2012 OI Morales-Menendez, Ruben/0000-0003-0498-1566 NR 29 TC 33 Z9 33 U1 0 U2 2 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 0018-9219 EI 1558-2256 J9 P IEEE JI Proc. IEEE PD MAR PY 2004 VL 92 IS 3 BP 455 EP 468 DI 10.1109/JPROC.2003.823157 PG 14 WC Engineering, Electrical & Electronic SC Engineering GA 800CA UT WOS:000220005300005 ER PT J AU Dobson, CC Jones, JE Chavers, DG AF Dobson, CC Jones, JE Chavers, DG TI Instrument reflections and scene amplitude modulation in a polychromatic microwave quadrature interferometer SO REVIEW OF SCIENTIFIC INSTRUMENTS LA English DT Article AB A polychromatic microwave quadrature interferometer has been characterized using several laboratory plasmas. Reflections between the transmitter and the receiver have been observed, and the effects of including reflection terms in the data reduction equation have been examined. An error analysis which includes the reflections, modulation of the scene beam amplitude by the plasma, and simultaneous measurements at two frequencies has been applied to the empirical database, and the results are summarized. For reflection amplitudes around 10%, the reflection terms were found to reduce the calculated error bars for electron density measurements by about a factor of 2. The impact of amplitude modulation is also quantified. In the complete analysis, the mean error bar for high-density measurements is 7.5%, and the mean phase shift error for low-density measurements is 1.2degrees. C1 NASA, George C Marshall Space Flight Ctr, Propuls Res Ctr, Huntsville, AL 35812 USA. RP Dobson, CC (reprint author), NASA, George C Marshall Space Flight Ctr, Propuls Res Ctr, Huntsville, AL 35812 USA. EM christopher.c.dobson@nasa.gov NR 7 TC 5 Z9 5 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 MAR PY 2004 VL 75 IS 3 BP 674 EP 683 DI 10.1063/1.1646738 PG 10 WC Instruments & Instrumentation; Physics, Applied SC Instruments & Instrumentation; Physics GA 775RU UT WOS:000189075100012 ER PT J AU Moran, TG AF Moran, TG TI Thomas Gold's assertion SO SCIENTIFIC AMERICAN LA English DT Letter C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Moran, TG (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 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 MAR PY 2004 VL 290 IS 3 BP 14 EP 14 PG 1 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 773GD UT WOS:000188888600011 ER PT J AU Hansen, J AF Hansen, J TI Defusing the global warming time bomb SO SCIENTIFIC AMERICAN LA English DT Article C1 NASA, Goddard Inst Space Studies, Greenbelt, MD USA. Columbia Univ, Earth Inst, New York, NY USA. RP Hansen, J (reprint author), NASA, Goddard Inst Space Studies, Greenbelt, MD USA. NR 0 TC 48 Z9 49 U1 0 U2 17 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 MAR PY 2004 VL 290 IS 3 BP 68 EP 77 PG 10 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 773GD UT WOS:000188888600033 PM 14981880 ER PT J AU Stothers, RB AF Stothers, RB TI Ancient and modern earthquake lights in Northwestern Turkey SO SEISMOLOGICAL RESEARCH LETTERS LA English DT Article ID IZMIT EARTHQUAKE C1 NASA, Goddard Space Flight Ctr, Inst Space Studies, New York, NY 10025 USA. RP Stothers, RB (reprint author), NASA, Goddard Space Flight Ctr, Inst Space Studies, 2880 Broadway, New York, NY 10025 USA. EM rstothers@giss.nasa.gov NR 59 TC 6 Z9 6 U1 0 U2 0 PU SEISMOLOGICAL SOC AMER PI EL CERRITO PA PLAZA PROFESSIONAL BLDG, SUITE 201, EL CERRITO, CA 94530 USA SN 0895-0695 J9 SEISMOL RES LETT JI Seismol. Res. Lett. PD MAR-APR PY 2004 VL 75 IS 2 BP 199 EP 204 PG 6 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 815JA UT WOS:000221037400006 ER PT J AU Weaver, AR Kissel, DE Chen, F West, LT Adkins, W Rickman, D Luvall, JC AF Weaver, AR Kissel, DE Chen, F West, LT Adkins, W Rickman, D Luvall, JC TI Mapping soil pH buffering capacity of selected fields in the coastal plain SO SOIL SCIENCE SOCIETY OF AMERICA JOURNAL LA English DT Article ID ORGANIC-MATTER; LIME REQUIREMENT; CATION-EXCHANGE; ACID SOILS; ACIDIFICATION; SENSITIVITY AB Soil pH buffering capacity, since it varies spatially within crop production fields, may be used to define sampling zones to assess lime requirement, or for modeling changes in soil pH when acid-forming fertilizers or manures are added to a field. Our objective was to develop a procedure to map this soil property. One-hundred-thirty-six soil samples (0- to 15-cm depth) from three Georgia Coastal Plain fields were titrated with calcium hydroxide to characterize differences in pH buffering capacity of the soils. Since the relationship between soil pH and added calcium hydroxide was approximately linear for all samples up to pH 6.5, the slope values of these linear relationships for all soils were regressed on the organic C and clay contents of the 136 soil samples using multiple linear regression. The equation that fit the data best was b = 0.00029 - 0.00003 x percentage clay + 0.00135 x percentage OC-t, r(2) = 0.68, where b is the slope of pH vs. lime added, and OC is organic carbon. This equation was applied within geographic information system (GIS) software to create maps of soil pH buffering capacity for the three fields. When the mapped values of the pH buffering capacity were compared with measured values for a total of 18 locations in the three fields, there was good general agreement. A regression of directly measured pH buffering capacities on mapped pH buffering capacities at the field locations for these samples gave an r(2) of 0.88 with a slope of 1.04 for a group of soils that varied approximately tenfold in their pH buffering capacities. C1 Univ Georgia, Dept Crop & Soil Sci, Athens, GA 30602 USA. NASA, Global Hydrol & Climate Ctr, Huntsville, AL 35806 USA. RP Kissel, DE (reprint author), Univ Georgia, Dept Crop & Soil Sci, Athens, GA 30602 USA. EM dkissel@uga.edu OI Rickman, Doug/0000-0003-3409-2882 NR 24 TC 31 Z9 38 U1 3 U2 27 PU SOIL SCI SOC AMER PI MADISON PA 677 SOUTH SEGOE ROAD, MADISON, WI 53711 USA SN 0361-5995 J9 SOIL SCI SOC AM J JI Soil Sci. Soc. Am. J. PD MAR-APR PY 2004 VL 68 IS 2 BP 662 EP 668 PG 7 WC Soil Science SC Agriculture GA 800PR UT WOS:000220040700039 ER PT J AU Connerney, JEP Acuna, MH Ness, NF Spohn, T Schubert, G AF Connerney, JEP Acuna, MH Ness, NF Spohn, T Schubert, G TI Mars crustal magnetism SO SPACE SCIENCE REVIEWS LA English DT Review ID GLOBAL SURVEYOR MISSION; SPHERICAL HARMONIC MODEL; SOLAR-WIND INTERACTION; THERMAL EVOLUTION; TERRESTRIAL PLANETS; DEPENDENT VISCOSITY; GEOMAGNETIC-FIELD; LUNAR MAGNETISM; PLATE-TECTONICS; SNC METEORITES AB Mars lacks a detectable magnetic field of global scale, but boasts a rich spectrum of magnetic fields at smaller spatial scales attributed to the spatial variation of remanent magnetism in the crust. On average the Mars crust is 10 times more intensely magnetized than that of the Earth. It appears likely that the Mars crust acquired its remanence in the first few hundred million years of evolution when an active dynamo sustained an intense global field. An early dynamo era, ending in the Noachian, or earliest period of Mars chronology, would likely be driven by thermal convection in an early, hot, fluid core. If crustal remanence was acquired later in Mars history, a dynamo driven by chemical convection associated with the solidification of an inner core is likely. Thermal evolution models cannot yet distinguish between these two possibilities. The magnetic record contains a wealth of information on the thermal evolution of Mars and the Mars dynamo, but we have just begun to decipher its message. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Delaware, Wilmington, DE USA. Univ Munster, D-4400 Munster, Germany. Univ Calif Los Angeles, Los Angeles, CA 90024 USA. RP Connerney, JEP (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RI connerney, john/I-5127-2013; OI connerney, jack/0000-0001-7478-6462 NR 102 TC 37 Z9 36 U1 2 U2 5 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-6308 J9 SPACE SCI REV JI Space Sci. Rev. PD MAR PY 2004 VL 111 IS 1-2 BP 1 EP 32 DI 10.1023/B:SPAC.0000032719.40094.1d PG 32 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 831YW UT WOS:000222233800001 ER PT J AU Nagy, AF Winterhalter, D Sauer, K Cravens, TE Brecht, S Mazelle, C Crider, D Kallio, E Zakharov, A Dubinin, E Verigin, M Kotova, G Axford, WI Bertucci, C Trotignon, JG AF Nagy, AF Winterhalter, D Sauer, K Cravens, TE Brecht, S Mazelle, C Crider, D Kallio, E Zakharov, A Dubinin, E Verigin, M Kotova, G Axford, WI Bertucci, C Trotignon, JG TI The plasma environment of Mars SO SPACE SCIENCE REVIEWS LA English DT Review ID SOLAR-WIND INTERACTION; MARTIAN BOW SHOCK; MAGNETIC PILEUP BOUNDARY; ENERGETIC NEUTRAL ATOMS; ION COMPOSITION BOUNDARY; MULTISPECIES MAGNETOHYDRODYNAMIC MODEL; GLOBAL SURVEYOR OBSERVATIONS; FIELD DRAPING ENHANCEMENT; RADIO OCCULTATION METHODS; TURBULENT PICK-UP C1 Univ Michigan, Ann Arbor, MI 48109 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Max Planck Inst Aeron, D-37191 Katlenburg Lindau, Germany. Univ Kansas, Lawrence, KS 66045 USA. Bay Area Res Corp, Orinda, CA 94563 USA. CNRS, Ctr Etud Spatiale Rayonnements, Toulouse, France. Catholic Univ Amer, Dept Phys, Washington, DC 20064 USA. Finnish Meteorol Inst, FIN-00101 Helsinki, Finland. Russian Acad Sci, Space Res Inst, Moscow 117997, Russia. LPCE CNRS, Lab Phys & Chim & Environm, F-45071 Orleans 2, France. RP Nagy, AF (reprint author), Univ Michigan, 1416 Space Res, Ann Arbor, MI 48109 USA. RI Hurley, Dana/F-4488-2015; Kallio, Esa/F-9410-2014; OI Hurley, Dana/0000-0003-1052-1494; Kallio, Esa/0000-0002-9791-804X; Bertucci, Cesar/0000-0002-2540-5384 NR 259 TC 146 Z9 152 U1 2 U2 15 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-6308 EI 1572-9672 J9 SPACE SCI REV JI Space Sci. Rev. PD MAR PY 2004 VL 111 IS 1-2 BP 33 EP 114 DI 10.1023/B:SPAC.0000032718.47512.92 PG 82 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 831YW UT WOS:000222233800002 ER PT J AU Mazelle, C Winterhalter, D Sauer, K Trotignon, JG Acuna, MH Baumgartel, K Bertucci, C Brain, DA Brecht, SH Delva, M Dubinin, E Oieroset, M Slavin, J AF Mazelle, C Winterhalter, D Sauer, K Trotignon, JG Acuna, MH Baumgartel, K Bertucci, C Brain, DA Brecht, SH Delva, M Dubinin, E Oieroset, M Slavin, J TI Bow shock and upstream phenomena at Mars SO SPACE SCIENCE REVIEWS LA English DT Review ID SOLAR-WIND INTERACTION; PLASMA-WAVE SYSTEM; 3-DIMENSIONAL HYBRID SIMULATION; FREQUENCY ELECTROMAGNETIC-WAVES; DIAMAGNETIC CAVITIES UPSTREAM; PROTON CYCLOTRON FREQUENCY; FIELD DRAPING ENHANCEMENT; MAGNETIC PILEUP BOUNDARY; ION COMPOSITION BOUNDARY; EARTHS FORESHOCK REGION AB Mars Global Surveyor is the sixth spacecraft to return measurements of the Martian bow shock. The earlier missions were Mariner 4 ( 1964), Mars 2 and 3 ( 1972), Mars 5 ( 1975) and Phobos 2 (1989) (see reviews by Gringauz, 1981; Slavin and Holzer, 1982; Russell, 1985; Vaisberg, 1992a, b; Zakharov, 1992). Previous investigations of planetary bow shocks have established that their position, shape and jump conditions are functions of the upstream flow parameters and the nature of the solar wind-planet interaction (Spreiter and Stahara, 1980; Slavin et al., 1983; Russell, 1985). At Mars, however, the exact nature of the solar wind interaction was elusive due to the lack of low altitude plasma and magnetic field measurements (e.g., Axford, 1991). In fact our knowledge of the nature of the interaction of Mars with the solar wind was incomplete until the arrival of MGS and the acquisition of close-in magnetic field data (Acuna et al., 1998). As detailed by a series of review papers in this monograph, the Mars Global Surveyor ( MGS) mission has now shown that the Mars environment is very complex with strong, highly structured crustal magnetic remnants in the southern hemisphere, while the northern hemisphere experiences the direct impingement of solar wind plasma. This review paper first presents a survey of the observations on the Martian bow shock and the upstream phenomena in the light of results from all the missions to date. It also discusses the kinetic properties of the Martian bow shock compared to the predictions of simulations studies. Then it examines the current status of understanding of these phenomena, including the possible sources of upstream low-frequency waves and the interpretations of localized disturbances in the upstream solar wind around Mars. Finally, it briefly discusses the open issues and questions that require further study. C1 CNRS UPS, CESR, F-31400 Toulouse, France. CALTECH, Jet Prop Lab, Pasadena, CA USA. Max Planck Inst Aeron, Katlenburg Lindau, Germany. CNRS, LPCE, F-45071 Orleans, France. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Astrophys Inst Potsdam, Potsdam, Germany. Univ Colorado, Dept Astrophys & Planetary Sci, Boulder, CO 80309 USA. Berkeley Res Associates Inc, Berkeley, CA USA. Inst Weltraumforsch, Graz, Austria. Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. RP Mazelle, C (reprint author), CNRS UPS, CESR, 9-11 Ave Colonel Roche, F-31400 Toulouse, France. RI Slavin, James/H-3170-2012; OI Slavin, James/0000-0002-9206-724X; Bertucci, Cesar/0000-0002-2540-5384 NR 151 TC 57 Z9 56 U1 2 U2 19 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-6308 EI 1572-9672 J9 SPACE SCI REV JI Space Sci. Rev. PD MAR PY 2004 VL 111 IS 1-2 BP 115 EP 181 DI 10.1023/B:SPAC.0000032717.98679.d0 PG 67 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 831YW UT WOS:000222233800003 ER PT J AU Oieroset, M Mitchell, DL Phan, TD Lin, RP Crider, DH Acuna, MH AF Oieroset, M Mitchell, DL Phan, TD Lin, RP Crider, DH Acuna, MH TI The magnetic field pile-up and density depletion in the martian magnetosheath: A comparison with the plasma depletion layer upstream of the Earth's magnetopause SO SPACE SCIENCE REVIEWS LA English DT Review ID MARS GLOBAL SURVEYOR; SOLAR-WIND INTERACTION; ELECTRON-IMPACT IONIZATION; ION COMPOSITION BOUNDARY; SUBSOLAR MAGNETOSHEATH; DAYSIDE MAGNETOPAUSE; MAG/ER EXPERIMENT; IONOSPHERE; PRESSURE; MISSION AB Using magnetometer and electron observations from the Mars Global Surveyor (MGS) and the Wind spacecraft we show that the region of magnetic field pile-up and density decrease located between the Martian ionosphere and bow shock exhibit strong similarities with the plasma depletion layer (PDL) observed upstream of the Earth's magnetopause in the absence of magnetic reconnection when the magnetopause is a solid obstacle in the solar wind. A PDL is formed upstream of the terrestrial magnetopause when the magnetic field piles up against the obstacle and particles in the pile-up region are squeezed away from the high magnetic pressure region along the field lines as the flux tubes convect toward the magnetopause. We here discuss the possibility that at least part of the region of magnetic field pile-up and density depletion upstream of Mars may be formed by the same physical processes which generate the PDL upstream of the Earth's magnetopause. More complete ion, electron, and neutral measurements are needed to conclusively determine the relative importance of the plasma depletion process versus exospheric processes. C1 Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Oieroset, M (reprint author), Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. RI Hurley, Dana/F-4488-2015 OI Hurley, Dana/0000-0003-1052-1494 NR 41 TC 11 Z9 11 U1 0 U2 2 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-6308 J9 SPACE SCI REV JI Space Sci. Rev. PD MAR PY 2004 VL 111 IS 1-2 BP 185 EP 202 DI 10.1023/B:SPAC.0000032715.69695.9c PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 831YW UT WOS:000222233800004 ER PT J AU Crider, DH Brain, DA Acuna, MH Vignes, D Mazelle, C Bertucci, C AF Crider, DH Brain, DA Acuna, MH Vignes, D Mazelle, C Bertucci, C TI Mars Global Surveyor observations of solar wind magnetic field draping around Mars SO SPACE SCIENCE REVIEWS LA English DT Review ID MARTIAN MAGNETOTAIL; BOW SHOCK; VENUS; SPACECRAFT; BOUNDARY; MAGNETOSPHERE; PLANETS; MODEL; FLOW; MHD AB We examine the magnetic field in the martian magnetosheath due to solar wind draping. Mars Global Surveyor provided 3-D vector magnetic field measurements at a large range of altitudes, local times, and solar zenith angles as the spacecraft orbit evolved. We choose orbits with very clean signatures of draping to establish the nominal morphology of the magnetic field lines at local times of near-subsolar and near-terminator. Next, using a compilation of data from Mars Global Surveyor, we determine the average magnetic field morphology in the martian magnetosheath due to the solar wind interaction. The topology of the field is as expected from previous observations and predictions. The magnetic field magnitude peaks at low altitude and noon magnetic local time and decreases away from that point. The magnetic field has an inclination from the local horizontal of 5.6degrees on average in the dayside magnetosheath and 12.5degrees on the nightside. The inclination angle is closest to zero at noon magnetic local time and low altitude. It increases both upward and to later local times. The magnetic field in the induced magnetotail flares out from the Mars-Sun direction by 21degrees. Finally, we compare the observations to gasdynamic model predictions and find that the shocked solar wind flow in the martian magnetosheath can be treated as a gasdynamic flow with the magnetic pileup boundary as the inner boundary to the flow. C1 Catholic Univ Amer, Dept Phys, Washington, DC 20064 USA. Univ Colorado, Boulder, CO 80309 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. CNRS UPS, Ctr Etud Spatiale Rayonnements, Toulouse, France. RP Crider, DH (reprint author), Catholic Univ Amer, Dept Phys, Washington, DC 20064 USA. RI Hurley, Dana/F-4488-2015; OI Hurley, Dana/0000-0003-1052-1494; Bertucci, Cesar/0000-0002-2540-5384 NR 35 TC 35 Z9 37 U1 1 U2 1 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-6308 J9 SPACE SCI REV JI Space Sci. Rev. PD MAR PY 2004 VL 111 IS 1-2 BP 203 EP 221 DI 10.1023/B:SPAC.0000032714.66124.4e PG 19 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 831YW UT WOS:000222233800005 ER PT J AU Vignes, D Acuna, MH Connerney, JEP Crider, DH Reme, H Mazelle, C AF Vignes, D Acuna, MH Connerney, JEP Crider, DH Reme, H Mazelle, C TI Magnetic flux ropes in the Martian atmosphere: Global characteristics SO SPACE SCIENCE REVIEWS LA English DT Review ID VENUS IONOSPHERE; FIELDS; MARS AB We report observations of magnetic fields amplitude, which consist of a series of individual spikes in the Martian atmosphere. A minimum variance analysis shows that these spikes form twisted cylindrical filaments. These small diameter magnetic filaments are commonly called magnetic flux ropes. We examine the global characteristics of magnetic flux ropes, which are observed on 5% of the elliptical orbits of Mars Global Surveyor. Flux ropes are more often observed in Venus' atmosphere (70% of the orbits). In this paper we report some of the global characteristics of the flux ropes identified in the Martian atmosphere. No flux ropes are observed in the southern hemisphere of Mars. Most of them occur at high solar zenith angles, close to the terminator plane, and at high latitude with altitudes below 400 km. The orientation of the flux ropes appears random while in the case of Venus the orientation is more horizontal near the terminator for altitudes greater than 200 km. We have identified fewer flux ropes for SZA between 40 to 60 deg and for SZA lower than 20 deg, like in the case of Venus (Elphic and Russell, 1983b). Statistically, Mars' ionosphere with SZA range between 40(circ) to 60(circ) is less magnetized than near the subsolar point. As the Martian ionosphere is quite often magnetized by the magnetic components of the crustal field, this crustal magnetic field seems to inhibit the flux ropes formation in the southern hemisphere. However, some orbits without crustal magnetic field, called magnetic cavities, were observed without flux ropes. So the flux ropes formation process seems to be suppressed by another factor, like the solar wind dynamic pressure for Venus (Krymskii and Breus, 1988). C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Ctr Etud Spatiale Rayonnements, Toulouse, France. RP Vignes, D (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. EM vignes@lepmom.gsfc.nasa.gov RI connerney, john/I-5127-2013; Hurley, Dana/F-4488-2015; OI Hurley, Dana/0000-0003-1052-1494; connerney, jack/0000-0001-7478-6462 NR 11 TC 28 Z9 28 U1 0 U2 1 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-6308 J9 SPACE SCI REV JI Space Sci. Rev. PD MAR PY 2004 VL 111 IS 1-2 BP 223 EP 231 DI 10.1023/B:SPAC.0000032716.21619.f2 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 831YW UT WOS:000222233800006 ER PT J AU Verigin, MI Slavin, J Szabo, A Kotova, GA Remizov, AP Rosenbauer, H Livi, S Szego, K Tatrallyay, M Schwingenschuh, K Zhang, TL AF Verigin, MI Slavin, J Szabo, A Kotova, GA Remizov, AP Rosenbauer, H Livi, S Szego, K Tatrallyay, M Schwingenschuh, K Zhang, TL TI Unusually distant bow shock encounters at Mars: Analysis of March 24, 1989 event SO SPACE SCIENCE REVIEWS LA English DT Review ID SOLAR-WIND INTERACTION; CRUSTAL MAGNETIZATION; MARTIAN MAGNETOSPHERE; PHOBOS-2 OBSERVATIONS; MAG/ER EXPERIMENT; GLOBAL SURVEYOR; RAM PRESSURE; 3-D SHAPE; BOUNDARY; MAGNETOPAUSE AB Detailed analysis of disturbances observed on 24 March, 1989 far upstream of the usual Martian bow shock position was completed with the use of the planetary obstacle and bow shock models relevant for the period of Phobos 2 observations and for low Mach numbers, respectively. It is proven that the system of discontinuities observed in the solar wind between 18: 42 and 19: 36 UT was the consequence of unusually distant planetary bow shock excursions. The cause was unusually small rhoV(2) and M-a values in the solar wind flow. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Russian Acad Sci, Inst Space Res, Moscow V71, Russia. Max Planck Inst Aeron, Katlenburg, Germany. HU, Appl Phys Lab, Laurel, MD USA. KFKI, Res Inst Particle & Nucl Phys, Budapest, Hungary. Austrian Acad Sci, Space Res Inst, A-8010 Graz, Austria. RP Verigin, MI (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RI Slavin, James/H-3170-2012 OI Slavin, James/0000-0002-9206-724X NR 23 TC 5 Z9 5 U1 1 U2 2 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-6308 J9 SPACE SCI REV JI Space Sci. Rev. PD MAR PY 2004 VL 111 IS 1-2 BP 233 EP 243 DI 10.1023/B:SPAC.0000032713.86796.d1 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 831YW UT WOS:000222233800007 ER PT J AU Hilburger, MW Starnes, JH AF Hilburger, MW Starnes, JH TI Effects of imperfections of the buckling response of composite shells SO THIN-WALLED STRUCTURES LA English DT Article DE buckling; composite shells; imperfections; failure AB The results of an experimental and analytical study of the effects of initial imperfections on the buckling response and failure of unstiffened thin-walled compression-loaded graphite-epoxy cylindrical shells are presented. The shells considered in the study have six different shell-wall laminates two different shell-radius-to-thickness ratios. The shell-wall laminates include four different orthotropic laminates and two different quasi-isotropic laminates. The shell-radius-to-thickness ratios includes shell-radius-to-thickness ratios equal to 100 and 200. The numerical results include the effects of traditional and nontraditional initial imperfections and selected shell parameter uncertainties. The traditional imperfections include the geometric shell-wall mid-surface imperfections that are commonly discussed in the literature on thin shell buckling. The nontraditional imperfections include shell-wall thickness variations, local shell-wall ply-gaps associated with the fabrication process, shell-end geometric imperfections, nonuniform applied end loads, and variations in the boundary conditions including the effects of elastic boundary conditions. The cylinder parameter uncertainties considered include uncertainties in geometric imperfection measurements, lamina fiber volume fraction, fiber and matrix properties, boundary conditions, and applied end load distribution. Results that include the effects of these traditional and nontraditional imperfections and uncertainties on the nonlinear response characteristics, buckling loads and failure of the shells are presented. The analysis procedure includes a nonlinear static analysis that predicts the stable response characteristics of the shells, and a nonlinear transient analysis that predicts the unstable response characteristics. In addition, a common failure analysis is used to predict material failures in the shells. Published by Elsevier Ltd. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Hilburger, MW (reprint author), NASA, Langley Res Ctr, MS 190, Hampton, VA 23681 USA. EM mark.w.hilburger@nasa.gov NR 16 TC 26 Z9 29 U1 1 U2 7 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0263-8231 J9 THIN WALL STRUCT JI Thin-Walled Struct. PD MAR PY 2004 VL 42 IS 3 BP 369 EP 397 DI 10.1016/j.tws.2003.09.001 PG 29 WC Engineering, Civil SC Engineering GA 778GX UT WOS:000189232200002 ER PT J AU Barron, MG Carls, MG Heintz, R Rice, SD AF Barron, MG Carls, MG Heintz, R Rice, SD TI Evaluation of fish early life-stage toxicity models of chronic embryonic exposures to complex polycyclic aromatic hydrocarbon mixtures SO TOXICOLOGICAL SCIENCES LA English DT Article DE polycyclic aromatic hydrocarbon; aryl hydrocarbon receptor; narcosis; fish embryo ID TROUT ONCORHYNCHUS-MYKISS; WEATHERED CRUDE-OIL; RAINBOW-TROUT; MORTALITY; WATER; 2,3,7,8-TETRACHLORODIBENZO-P-DIOXIN; SENSITIVITY; INDUCTION; RETENE; DAMAGE AB Polycyclic aromatic hydrocarbons (PAHs) can cause a variety of effects in early life-stages of fish that have been chronically exposed as embryos, including mortality, deformities, and edemas. Mechanistic models of the chronic toxicity of complex mixtures of PAHs in fish have not been reported, with the exception of a previously untested model based on the lipids of fish as the site of action and toxicity caused through a narcosis mechanism. Four mechanism-based models of the chronic toxicity of embryonic exposures to complex mixtures of petrogenic PAHs in two species of fish, Pacific herring and pink salmon, were evaluated using a toxic-units approach: narcosis, aryl hydrocarbon receptor (AhR) agonism, alkyl phenanthrene toxicity, and combined toxicity. Alkyl phenanthrenes were the predominant PAH constituent determining early life-stage toxicity in both herring and salmon. The alkyl phenanthrene model had 67 to 80% accuracy in predicting the absence or presence of significant early life-stage toxicity, compared with a 40 to 50% accuracy and general underprediction of toxicity with the narcosis model. PAHs with high relative AhR affinity did not appear to contribute substantially to the observed early life-stage toxicity because of low concentrations of the most potent AhR agonists. Narcosis appeared to primarily contribute to embryo mortality and to be predominantly controlled by the concentration of naphthalenes. Except for the highest PAH exposure to herring, the primary toxic unit contribution to the combined toxicity model was alkyl phenanthrene toxicity to both herring and salmon. We recommend the continued use of total PAHs as a metric of exposure until mechanistic models have been further evaluated. C1 PEAK Res, Longmont, CO 80501 USA. Natl Marine Fisheries Serv, Auke Bay Lab, Juneau, AK 99801 USA. RP Barron, MG (reprint author), US EPA, 1 Sabine Isl Dr, Gulf Breeze, FL 32561 USA. EM barron.mace@epa.gov NR 23 TC 105 Z9 107 U1 2 U2 55 PU OXFORD UNIV PRESS PI OXFORD PA GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND SN 1096-6080 J9 TOXICOL SCI JI Toxicol. Sci. PD MAR PY 2004 VL 78 IS 1 BP 60 EP 67 DI 10.1093/toxsci/kfh051 PG 8 WC Toxicology SC Toxicology GA 801DG UT WOS:000220076000008 PM 14691206 ER PT J AU DellaCorte, C AF DellaCorte, C TI Polishing the crystal ball SO TRIBOLOGY & LUBRICATION TECHNOLOGY 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. EM cdellacorte@stle.org 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 TRIBOL LUBR TECHNOL JI Tribol. Lubr. Technol. PD MAR PY 2004 VL 60 IS 3 BP 6 EP 6 PG 1 WC Engineering, Mechanical SC Engineering GA 780BL UT WOS:000189351200002 ER PT J AU Siebe, C Rodriguez-Lara, V Schaaf, P Abrams, M AF Siebe, C Rodriguez-Lara, V Schaaf, P Abrams, M TI Geochemistry, Sr-Nd isotope composition, and tectonic setting of Holocene Pelado, Guespalapa and Chichinautzin scoria cones, south of Mexico city SO JOURNAL OF VOLCANOLOGY AND GEOTHERMAL RESEARCH LA English DT Review DE Chichinautzin; scoria cone; geochemistry; Sr-Nd isotopes; trans-Mexican volcanic belt ID SAN-LUIS-POTOSI; SUBDUCTION ZONE MAGMATISM; PLUME-RELATED MAGMATISM; LOWER CRUSTAL XENOLITHS; CALC-ALKALIC VOLCANISM; ISLAND BASALT TYPE; POPOCATEPETL VOLCANO; TRACE-ELEMENT; UPPER-MANTLE; PERIDOTITE XENOLITHS AB Holocene Pelado, Guespalapa and Chichinautzin monogenetic scoria cones and associated lava flows located within the Sierra del Chichinautzin Volcanic Field (SCVF) at the southern margin of Mexico City were mapped and sampled for mineralogical and chemical analyses. With the exception of Paricutin volcano in western Mexico, few scoria cones in the Trans-Mexican Volcanic Belt have ever been sampled in greater detail. Chemical analyses of rocks indicate that mafic products (e.g. Guespalapa and Chichinautzin) from individual volcanoes in the Sierra del Chichinautzin are characterized by substantial chemical variability, whereas high-silica andesite volcanoes (e.g. Pelado) are very uniform in composition. These findings have important bearings for regional tephrochronology. As a whole, rock compositions form a continuous coherent calc-alkaline suite, explicable by polybaric fractional crystallization +/- assimilation associated with successive stagnation at different depths along the ascent path. Trace element and Sr-Nd isotope analyses point toward a < 1-km-scale heterogeneous (enriched/depleted) mantle wedge underneath the SCVF. The recently proposed plume-origin for these rocks is not in accord with our data. Instead, magma origin is discussed in relation to the tectonically complex subduction process of the oceanic Cocos Plate underneath the continental North American Plate. (C) 2003 Elsevier B.V. All rights reserved. C1 Univ Nacl Autonoma Mexico, Inst Geofis, Mexico City 04510, DF, Mexico. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Siebe, C (reprint author), Univ Nacl Autonoma Mexico, Inst Geofis, Mexico City 04510, DF, Mexico. EM csiebe@tonatiuh.igeofcu.unam.mx OI Siebe, Claus/0000-0002-3959-9028 NR 104 TC 65 Z9 70 U1 1 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0377-0273 J9 J VOLCANOL GEOTH RES JI J. Volcanol. Geotherm. Res. PD FEB 29 PY 2004 VL 130 IS 3-4 BP 197 EP 226 DI 10.1016/S0377-0273(03)00289-0 PG 30 WC Geosciences, Multidisciplinary SC Geology GA 768MM UT WOS:000188546800002 ER PT J AU Imhoff, ML Bounoua, L DeFries, R Lawrence, WT Stutzer, D Tucker, CJ Ricketts, T AF Imhoff, ML Bounoua, L DeFries, R Lawrence, WT Stutzer, D Tucker, CJ Ricketts, T TI The consequences of urban land transformation on net primary productivity in the United States SO REMOTE SENSING OF ENVIRONMENT LA English DT Article DE carbon cycle; NPP; urbanization; urban heating ID HUMAN APPROPRIATION; SATELLITE DATA; CITY LIGHTS; CANOPY REFLECTANCE; PHOTOSYNTHESIS; BIODIVERSITY; POPULATION; MODEL; AREA; SUSTAINABILITY AB We use data from two satellites and a terrestrial carbon model to quantify the impact of urbanization on the carbon cycle and food production in the US as a result of reduced net primary productivity (NPP). Our results show that urbanization is taking place on the most fertile lands and hence has a disproportionately large overall negative impact on NPP. Urban land transformation in the US has reduced the amount of carbon fixed through photosynthesis by 0.04 pg per year or 1.6% of the pre-urban input. The reduction is enough to offset the 1.8% gain made by the conversion of land to agricultural use, even though urbanization covers an area less than 3% of the land surface in the US and agricultural lands approach 29% of the total land area. At local and regional scales, urbanization increases NPP in resource-limited regions and through localized warming "urban heat" contributes to the extension of the growing season in cold regions. In terms of biologically available energy, the loss of NPP due to urbanization of agricultural lands alone is equivalent to the caloric requirement of 16.5 million people, or about 6% of the US population. (C) 2004 Elsevier Inc. All rights reserved. C1 NASA, Goddard Space Flight Ctr, Biospher Sci Branch, Greenbelt, MD 20771 USA. Univ Maryland, Earth Syst Sci Interdisciplinary Ctr, College Pk, MD 20742 USA. Univ Maryland, Dept Geog, College Pk, MD 20742 USA. Bowie State Univ, Dept Nat Sci, Bowie, MD 20715 USA. Stanford Univ, Dept Sci Biol, Ctr Conservat Biol, Stanford, CA 94305 USA. RP Imhoff, ML (reprint author), NASA, Goddard Space Flight Ctr, Biospher Sci Branch, Code 923, Greenbelt, MD 20771 USA. EM Marc.L.Imhoff@nasa.gov NR 51 TC 156 Z9 181 U1 8 U2 66 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 FEB 29 PY 2004 VL 89 IS 4 BP 434 EP 443 DI 10.1016/j.rse.2003.10.015 PG 10 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA 777GA UT WOS:000189166600003 ER PT J AU Dalton, JB Bove, DJ Mladinich, CS Rockwell, BW AF Dalton, JB Bove, DJ Mladinich, CS Rockwell, BW TI Identification of spectrally similar materials using the USGS Tetracorder algorithm: the calcite-epidote- chlorite problem SO REMOTE SENSING OF ENVIRONMENT LA English DT Article DE USGS Tetracorder system; calcite; epidote; chlorite ID REFLECTANCE SPECTROSCOPY AB A scheme to discriminate and identify materials having overlapping spectral absorption features has been developed and tested based on the U.S. Geological Survey (USGS) Tetracorder system. The scheme has been applied to remotely sensed imaging spectroscopy data acquired by the Airborne Visible and Infrared Imaging Spectrometer (AVIRIS) instrument. This approach was used to identify the minerals calcite, epidote, and chlorite in the upper Animas River watershed, Colorado. The study was motivated by the need to characterize the distribution of calcite in the watershed and assess its acid-neutralizing potential with regard to acidic mine drainage. Identification of these three minerals is difficult because their diagnostic spectral features are all centered at 2.3 mum, and have similar shapes and widths. Previous studies overestimated calcite abundance as a result of these spectral overlaps. The use of a reference library containing synthetic mixtures of the three minerals in varying proportions was found to simplify the task of identifying these minerals when used in conjunction with a rule-based expert system. Some inaccuracies in the mineral distribution maps remain, however, due to. the influence of a fourth spectral component, sericite, which exhibits spectral absorption features at 2.2 and 2.4 mum that overlap the 2.3-mum absorption features of the other three minerals. Whereas the endmember minerals calcite, epidote, chlorite, and sericite can be identified by the method presented here, discrepancies occur in areas where all four occur together as intimate mixtures. It is expected that future work will be able to reduce these discrepancies by including reference mixtures containing sericite. (C) 2004 Elsevier Inc. All rights reserved. C1 NASA, Ames Res Ctr, SETI Inst, Planetary Syst Branch, Moffett Field, CA 94035 USA. US Geol Survey, Lakewood, CO 80225 USA. RP Dalton, JB (reprint author), NASA, Ames Res Ctr, SETI Inst, Planetary Syst Branch, MS 245-3, Moffett Field, CA 94035 USA. EM dalton@mail.arc.nasa.gov NR 47 TC 24 Z9 25 U1 1 U2 8 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 FEB 29 PY 2004 VL 89 IS 4 BP 455 EP 466 DI 10.1016/j.rse.2003.11.011 PG 12 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA 777GA UT WOS:000189166600005 ER PT J AU Chesley, J Righter, K Ruiz, J AF Chesley, J Righter, K Ruiz, J TI Large-scale mantle metasomatism: a Re-Os perspective SO EARTH AND PLANETARY SCIENCE LETTERS LA English DT Article DE rhenium; osmium; metasomatism; subduction fluids; mantle melt ID GROUP ELEMENT ABUNDANCES; PLATINUM-GROUP ELEMENTS; LITHOSPHERIC MANTLE; ISOTOPE SYSTEMATICS; PERIDOTITE XENOLITHS; ULTRAMAFIC XENOLITHS; SULFIDE INCLUSIONS; SUBDUCTION ZONES; MELT PERCOLATION; OCEANIC-CRUST AB There is a debate on the behavior of Re and Os during mantle metasomatism. Some argue that the mantle can acquire high Os-187/Os-188 (0.15 to > 1.0) either directly from metasomatic events or by the growth of Os-187 from Re-187 over time. However, any suggestions of subduction-related Os metasomatism producing whole-scale elevation of the mantle to Os-187/Os-188 values greater than 0.15 need to be supported by comparisons of increased Re and Os concentrations and isotopic ratios, with like and consistent increases in elements (i.e., Ba, B, Rb) and isotopic ratios (i.e., Nd, Pb, Sr) known to be affected by metasomatic processes. All of the samples in the literature, either xenoliths or minerals (sulfides.. pyroxene, phlogopite or amphibole) that are thought to represent the products of mantle metasomatism, follow a clear correlation of increasing Re/Os with decreasing Os concentration. This inverse correlation requires enrichment in Os concentrations in the metasomatizing agent by two to four orders of magnitude relative to the original subduction component in order to substantially elevate Os-187/Os-188, eliminating sediment or slab melts as an effective metasomatic component. To date there is no evidence to support conclusions that Os metasomatism, either directly or by a two-stage process involving Re metasomatism and Os-187 growth over time, will substantially change the Os-187/Os-188 of the mantle to values >0.15. When other isotopic systems are considered along with Os. in metasomatism-based models, these models are not plausible. Consequently, large-scale mantle melts should reflect near-chondritic values. The recognition of the robustness of the Re-Os system will allow for the discrimination of different mantle and crustal reservoirs involved in magmatic processes. (C) 2004 Elsevier B.V. All rights reserved. C1 Univ Arizona, Dept Geosci, Tucson, AZ 85721 USA. Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Chesley, J (reprint author), Univ Arizona, Dept Geosci, Tucson, AZ 85721 USA. EM jchesley@geo.arizona.edu NR 70 TC 62 Z9 68 U1 1 U2 18 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0012-821X J9 EARTH PLANET SC LETT JI Earth Planet. Sci. Lett. PD FEB 28 PY 2004 VL 219 IS 1-2 BP 49 EP 60 DI 10.1016/S0012-821X(03)00698-8 PG 12 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 778EF UT WOS:000189225900005 ER PT J AU Alexandrov, MD Marshak, A Cairns, B Lacis, AA Carlson, BE AF Alexandrov, MD Marshak, A Cairns, B Lacis, AA Carlson, BE TI Automated cloud screening algorithm for MFRSR data SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID AEROSOL OPTICAL DEPTH; SCATTERING; RADIOMETER; MODELS AB A new automated cloud screening algorithm for ground-based sun-photometric measurements is described and illustrated on examples of real (MFRSR) and simulated data. The algorithm uses single channel direct beam measurements and is based on variability analysis of retrieved optical thickness. To quantify this variability the inhomogeneity parameter e is used. This parameter is commonly used for cloud remote sensing and modeling, but not for cloud screening. In addition to this an adjustable enveloping technique is applied to control strictness of the selection method. The key advantages of this technique are its objectivity, computational efficiency and the ability to detect short clear-sky intervals under broken cloud cover conditions. Moreover, it does not require any knowledge of the instrument calibration. The performance of the method has been compared with that of AERONET cloud screening algorithm. C1 Columbia Univ, Dept Appl Phys & Appl Math, New York, NY 10027 USA. NASA, Goddard Inst Space Studies, New York, NY 10025 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Alexandrov, MD (reprint author), Columbia Univ, Dept Appl Phys & Appl Math, New York, NY 10027 USA. EM malexandrov@giss.nasa.gov RI Marshak, Alexander/D-5671-2012; Lacis, Andrew/D-4658-2012; Carlson, Barbara/D-8319-2012; OI Cairns, Brian/0000-0002-1980-1022 NR 16 TC 42 Z9 42 U1 0 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD FEB 28 PY 2004 VL 31 IS 4 AR L04118 DI 10.1029/2003GL019105 PG 5 WC Geosciences, Multidisciplinary SC Geology GA 803FC UT WOS:000220216000005 ER PT J AU Rex, M Salawitch, RJ von der Gathen, P Harris, NRP Chipperfield, MP Naujokat, B AF Rex, M Salawitch, RJ von der Gathen, P Harris, NRP Chipperfield, MP Naujokat, B TI Arctic ozone loss and climate change SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID STRATOSPHERIC TEMPERATURE; WINTER; MODEL; AEROSOL; TRENDS AB We report the first empirical quantification of the relation between winter-spring loss of Arctic ozone and changes in stratospheric climate. Our observations show that similar to 15 DU additional loss of column ozone can be expected per Kelvin cooling of the Arctic lower stratosphere, an impact nearly three times larger than current model simulations suggest. We show that stratospheric climate conditions became significantly more favorable for large Arctic ozone losses over the past four decades; i.e., the maximum potential for formation of polar stratospheric clouds increased steadily by a factor of three. Severe Arctic ozone loss during the past decade occurred as a result of the combined effect of this long-term climate change and the anthropogenic increase in stratospheric halogens. C1 Alfred Wegener Inst Polar & Marine Res, Potsdam, Germany. CALTECH, Jet Prop Lab, Pasadena, CA USA. European Ozone Res Coordinating Unit, Cambridge, England. Univ Leeds, Sch Environm, Leeds, W Yorkshire, England. Free Univ Berlin, Inst Meteorol, D-1000 Berlin, Germany. RP Rex, M (reprint author), Alfred Wegener Inst Polar & Marine Res, Potsdam, Germany. EM mrex@awi-potsdam.de RI Rex, Markus/A-6054-2009; Salawitch, Ross/B-4605-2009; von der Gathen, Peter/B-8515-2009; Chipperfield, Martyn/H-6359-2013; OI Rex, Markus/0000-0001-7847-8221; Salawitch, Ross/0000-0001-8597-5832; von der Gathen, Peter/0000-0001-7409-1556; Chipperfield, Martyn/0000-0002-6803-4149; Harris, Neil/0000-0003-1256-3006 NR 19 TC 171 Z9 174 U1 1 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 FEB 28 PY 2004 VL 31 IS 4 AR L04116 DI 10.1029/2003GL018844 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 803FC UT WOS:000220216000001 ER PT J AU Wenig, M Kuhl, S Beirle, S Bucsela, E Jahne, B Platt, U Gleason, J Wagner, T AF Wenig, M Kuhl, S Beirle, S Bucsela, E Jahne, B Platt, U Gleason, J Wagner, T TI Retrieval and analysis of stratospheric NO2 from the Global Ozone Monitoring Experiment SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE GOME stratospheric NO2; DOAS; Noxon Cliff ID OPTICAL-ABSORPTION SPECTROSCOPY; NITROGEN-DIOXIDE; EXPERIMENT GOME; EMISSIONS; DEPLETION; BEHAVIOR; LATITUDE; AEROSOL; O-3; BRO AB [1] We describe the retrieval of stratospheric NO2 vertical column densities from the Global Ozone Monitoring Experiment (GOME) aboard the ERS-2 satellite. Different differential optical absorption spectroscopy (DOAS) evaluations are compared in order to investigate uncertainties caused by the diffuser plate. An improved version of our algorithm to separate the tropospheric and stratospheric fraction of NO2 from GOME satellite data is described and is used to extract a long term data set of stratospheric NO2 (1996 - 2000). In addition, the average seasonal variation in the global distribution is determined, which allows us to monitor and investigate specific aspects of stratospheric chemistry, in particular the interhemispheric comparison of stratospheric NO2. In contrast to other satellite observations (e.g., SAGE II, OSIRIS), GOME observations of stratospheric NO2 include the lower stratosphere. In general, our observations are in agreement with previous measurements and confirm the current knowledge of stratospheric nitrogen chemistry. C1 NASA, Goddard Space Flight Ctr, Atmospher Chem & Dynam Branch, Greenbelt, MD 20771 USA. Univ Heidelberg, Inst Umweltphys, D-69120 Heidelberg, Germany. Univ Heidelberg, Interdisziplinares Zentrum Wissensch Rechnen, D-69120 Heidelberg, Germany. RP Wenig, M (reprint author), NASA, Goddard Space Flight Ctr, Atmospher Chem & Dynam Branch, Code 916, Greenbelt, MD 20771 USA. EM wenig@code916.gsfc.nasa.gov RI Gleason, James/E-1421-2012; Wenig, Mark/K-7279-2012 NR 41 TC 19 Z9 19 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 FEB 28 PY 2004 VL 109 IS D4 AR D04315 DI 10.1029/2003JD003652 PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 803FM UT WOS:000220217000001 ER PT J AU Klimas, AJ Uritsky, VM Vassiliadis, D Baker, DN AF Klimas, AJ Uritsky, VM Vassiliadis, D Baker, DN TI Reconnection and scale-free avalanching in a driven current-sheet model SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article DE self-organized criticality; plasma sheet; simulation; scale-free; avalanche distributions; loading-unloading cycle ID SELF-ORGANIZED CRITICALITY; FIELD CURRENT INSTABILITY; ION WEIBEL INSTABILITY; EARTHWARD FLOW BURSTS; PLASMA SHEET; CURRENT DISRUPTION; MAGNETIC-FIELD; DYNAMIC MAGNETOSPHERE; SUBSTORM EXPANSIONS; STOCHASTIC-SYSTEMS AB [1] Uritsky et al. [ 2002], through a study of Polar UVI auroral image sequences, have produced a set of scale-free probability distributions for several characteristic properties of the evolving bright emission regions in the nightside auroral oval. These distributions almost certainly reflect the dynamics of the plasma sheet. A scale-free avalanching process involving reconnection and/or current diversion over an exceptionally broad range of spatiotemporal scales is implied. The most straightforward, and at present sole, explanation for this behavior is that the plasma sheet dynamics is in the neighborhood of self-organized criticality (SOC). However, the auroral images provide only an indirect measure of the plasma sheet dynamics. Confirmation of this state in the plasma sheet would require multispatiotemporal-scale in situ plasma sheet studies that, with the advent of multispacecraft missions, are now possible. To suggest specific tests for such studies, a numerical current-sheet model has been constructed and analyzed to develop the properties and requirements of SOC in a plasma physical setting. The model incorporates the anomalous resistivity of a current-driven kinetic instability into a two-dimensional resistive MHD system. The disparate scales of these two systems enable multiscale behavior in the intervening range. Several novel features in the model's behavior are enabled through the assumption of hysteresis in the kinetic instability threshold. Under steady loading of plasma containing a reversed magnetic field topology, an irregular loading-unloading cycle is established in which unloading is due primarily to annihilation at the field reversal. Following a loading interval during which the current-sheet supporting the field reversal thins and intensifies, an unloading event originates at a localized reconnection site that then becomes the source of waves of unstable current sheets. These current sheets propagate away from the reconnection site, each leaving a trail of anomalous resistivity behind. An expanding cascade of field line merging results. Some statistical properties of this cascade are examined. It is shown that the diffusive contribution to the Poynting flux in these cascades occurs in bursts, whose duration, integrated size, and total energy content exhibit scale-free power law probability distributions over large ranges of scales. Although not conclusive, these distributions do provide strong evidence that the model has evolved into SOC. C1 NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. Univ Colorado, Atmospher & Space Phys Lab, Boulder, CO 80309 USA. St Petersburg State Univ, Inst Phys, St Petersburg 198504, Russia. St Petersburg State Univ, Dept Phys, St Petersburg 198504, Russia. NASA, Goddard Space Flight Ctr, Univ Space Res Assoc, Greenbelt, MD 20771 USA. RP Klimas, AJ (reprint author), NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, 8800 Greenbelt Rd,Mail Code 692,Bldg 21 Room 265A, Greenbelt, MD 20771 USA. EM alex.klimas@gsfc.nasa.gov; uritsky@geo.phys.spbu.ru; vassi@electra.gsfc.nasa.gov; baker@lynx.colorado.edu NR 55 TC 41 Z9 41 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 FEB 27 PY 2004 VL 109 IS A2 AR A02218 DI 10.1029/2003JA010036 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 803GF UT WOS:000220218900002 ER PT J AU Koren, I Kaufman, YJ Remer, LA Martins, JV AF Koren, I Kaufman, YJ Remer, LA Martins, JV TI Measurement of the effect of Amazon smoke on inhibition of cloud formation SO SCIENCE LA English DT Article ID AIR-POLLUTION; CLIMATE; AEROSOLS; RADIATION; MICROPHYSICS; ATMOSPHERE; ALBEDO AB Urban air pollution and smoke from. res have been modeled to reduce cloud formation by absorbing sunlight, thereby cooling the surface and heating the atmosphere. Satellite data over the Amazon region during the biomass burning season showed that scattered cumulus cloud cover was reduced from 38% in clean conditions to 0% for heavy smoke ( optical depth of 1.3). This response to the smoke radiative effect reverses the regional smoke instantaneous forcing of climate from - 28 watts per square meter in cloud-free conditions to +8 watts per square meter once the reduction of cloud cover is accounted for. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. CNR, Washington, DC 20001 USA. Univ Maryland, Joint Ctr Earth Syst Technol, Baltimore, MD 21250 USA. RP Koren, I (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. EM ilank@climate.gsfc.nasa.gov RI Koren, Ilan/K-1417-2012 OI Koren, Ilan/0000-0001-6759-6265 NR 29 TC 334 Z9 346 U1 4 U2 46 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 FEB 27 PY 2004 VL 303 IS 5662 BP 1342 EP 1345 DI 10.1126/science.1089424 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 778JN UT WOS:000189238600043 PM 14988557 ER PT J AU Mahesh, A AF Mahesh, A TI Improved detection of large cirrus particles from infrared spectral observations SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID ANTARCTIC PLATEAU; RADIATION AB Spectral observations of cirrus clouds can be analyzed to obtain cloud particle effective radii using measurements at select wavenumbers in the infrared atmospheric window. The suitability of these wavenumbers to determine a range of sizes is constrained by the dependence on particle radius of ice absorption efficiency (Q(abs)). By using only those wavenumbers at which Q(abs) varies monotonically with radius, cloud particle radii up to approximately 20 mm can be determined; larger values, however, present problems. At some wavenumbers, the variation in Q(abs) is not sufficiently large to distinguish between large particle radii. At other wavenumbers, larger particles are more easily distinguished, but Q(abs) values do not correspond to unique particle radii. Using one set of wavenumbers only to determine whether the particle is large or small, and a second set to actually determine the effective radius of a large cloud particle, the limitations faced at individual wavenumbers can be partially overcome. This is demonstrated using yearlong spectral observations of ice clouds at South Pole station. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Maryland Baltimore Cty, Goddard Earth Sci & Technol Ctr, Baltimore, MD 21228 USA. RP Mahesh, A (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. EM mahesh@agnes.gsfc.nasa.gov NR 8 TC 0 Z9 0 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 EI 1944-8007 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD FEB 26 PY 2004 VL 31 IS 4 AR L04110 DI 10.1029/2003GL018768 PG 5 WC Geosciences, Multidisciplinary SC Geology GA 803EZ UT WOS:000220215700002 ER PT J AU Wang, O Fukumori, I Lee, T Johnson, GC AF Wang, O Fukumori, I Lee, T Johnson, GC TI Eastern equatorial Pacific Ocean T-S variations with El Nino SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID LA-NINA; CIRCULATION; VOLUME; MODEL AB Temperature-Salinity (T-S) relationship variability in the pycnocline of the eastern equatorial Pacific Ocean (NINO3 region, 5 degreesS - 5 degreesN, 150 degreesW - 90 degreesW) over the last two decades is investigated using observational data and model simulation. A numerical model simulation using the MITgcm ( Massachusetts Institute of Technology General Circulation Model) suggests that, during El Nino years, the water in the eastern equatorial Pacific Ocean becomes saltier (by 0.1 to 0.2) and warmer (by 0.5 to 1 degreesC) on density surfaces within the pycnocline. This simulation is consistent with Conductivity-Temperature-Depth (CTD) data collected mostly during Tropical Atmosphere Ocean (TAO) mooring maintenance cruises. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. NOAA, Pacific Marine Environm Lab, Seattle, WA 98115 USA. RP Wang, O (reprint author), CALTECH, Jet Prop Lab, MS 300-323,4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM owang@pacific.jpl.nasa.gov; if@pacific.jpl.nasa.gov; tlee@pacific.jpl.nasa.gov; gregory.c.johnson@noaa.gov RI Johnson, Gregory/I-6559-2012 OI Johnson, Gregory/0000-0002-8023-4020 NR 16 TC 4 Z9 4 U1 0 U2 6 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD FEB 26 PY 2004 VL 31 IS 4 AR L04305 DI 10.1029/2003GL019087 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 803EZ UT WOS:000220215700005 ER PT J AU Aires, F Prigent, C Rossow, WB AF Aires, F Prigent, C Rossow, WB TI Temporal interpolation of global surface skin temperature diurnal cycle over land under clear and cloudy conditions SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE surface skin temperature; diurnal cycle; temporal interpolation ID INFRARED SATELLITE-OBSERVATIONS; INDEPENDENT COMPONENT ANALYSIS; POLAR ORBITING SATELLITES; AIR-TEMPERATURE; MINIMUM TEMPERATURE; TIME-SERIES; MICROWAVE; ISCCP; EMISSIVITIES; RETRIEVAL AB [1] The surface skin temperature is a key parameter at the land-atmosphere interface. An accurate description of its diurnal cycle would not only help estimate the energy exchanges at the interface, it would also enable an analysis of the global surface skin diurnal cycle and its variability within the last 20 years. This study is based on the 3-hourly surface skin temperature estimated by the International Satellite Cloud Climatology Project (ISCCP) from the infrared measurements collected by the polar and geostationary meteorological satellites. The diurnal cycle of surface skin temperature is analyzed almost globally ( 60N - 60S snow-free areas), using a Principal Component Analysis. The first three components are identifyed as the amplitude, the phase, and the width (i.e., daytime duration) of the diurnal cycle and represent 97% of the variability. PCA is used to regularize estimates of the diurnal cycle at a higher time resolution. A new temporal interpolation algorithm, designed to work when only a few measurements of surface temperature are available, is developed based on the PCA representation and an iterative optimization algorithm. This method is very flexible: only temperature measurements are used ( no ancillary data), no surface model constraints are used, and the time and number of measurements are not fixed. The performance of this interpolation algorithm is tested for various diurnal sampling configurations. In particular, the potential to use the satellite microwave observations to provide a full diurnal surface temperature cycle in cloudy conditions is investigated. C1 Ecole Polytech, CNRS, Meteorol Dynam Lab, F-91128 Palaiseau, France. Columbia Univ, NASA, Goddard Inst Space Studies, Dept Appl Phys & Appl Math, New York, NY 10025 USA. Observ Paris, CNRS, Lab Etud Rayonnement & Mat Astrophys, F-75014 Paris, France. RP Aires, F (reprint author), Ecole Polytech, CNRS, Meteorol Dynam Lab, F-91128 Palaiseau, France. EM filipe.aires@lmd.polytechnique.fr; catherine.prigent@obspm.fr; wrossow@giss.nasa.gov RI Rossow, William/F-3138-2015 NR 32 TC 28 Z9 29 U1 2 U2 11 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD FEB 26 PY 2004 VL 109 IS D4 AR D04313 DI 10.1029/2003JD003527 PG 18 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 803FK UT WOS:000220216800001 ER PT J AU Pagan, KL Tabazadeh, A Drdla, K Hervig, ME Eckermann, SD Browell, EV Legg, MJ Foschi, PG AF Pagan, KL Tabazadeh, A Drdla, K Hervig, ME Eckermann, SD Browell, EV Legg, MJ Foschi, PG TI Observational evidence against mountain-wave generation of ice nuclei as a prerequisite for the formation of three solid nitric acid polar stratospheric clouds observed in the Arctic in early December 1999 SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE AVHRR; NAT PSC formation mechanism; mountain wave cooling ID LIDAR OBSERVATIONS; DENITRIFICATION; MICROPHYSICS; SCANDINAVIA; CLIMATOLOGY; RELEVANCE; CHEMISTRY AB [1] A number of recently published papers suggest that mountain-wave activity in the stratosphere, producing ice particles when temperatures drop below the ice frost point, may be the primary source of large NAT particles. In this paper we use measurements from the Advanced Very High Resolution Radiometer (AVHRR) instruments on board the National Oceanic and Atmospheric Administration (NOAA) polar-orbiting satellites to map out regions of ice clouds produced by stratospheric mountain-wave activity inside the Arctic vortex. Lidar observations from three DC-8 flights in early December 1999 show the presence of solid nitric acid ( Type Ia or NAT) polar stratospheric clouds (PSCs). By using back trajectories and superimposing the position maps on the AVHRR cloud imagery products, we show that these observed NAT clouds could not have originated at locations of high-amplitude mountain-wave activity. We also show that mountain-wave PSC climatology data and Mountain Wave Forecast Model 2.0 (MWFM-2) raw hemispheric ray and grid box averaged hemispheric wave temperature amplitude hindcast data from the same time period are in agreement with the AVHRR data. Our results show that ice cloud formation in mountain waves cannot explain how at least three large-scale NAT clouds were formed in the stratosphere in early December 1999. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. San Francisco State Univ, San Francisco, CA 94132 USA. G&A Tech Software Inc, Driggs, ID 83422 USA. USN, Middle Atmospher Dynam Sect, EO Hulburt Ctr Space Res, Res Lab, Washington, DC 20375 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. Bay Area Environm Res Inst, Sonoma, CA USA. San Francisco State Univ, Romberg Tiburon Ctr Environm Studies, Tiburon, CA 94920 USA. RP NASA, Ames Res Ctr, MS 245-5, Moffett Field, CA 94035 USA. EM pagan@cloud1.arc.nasa.gov; azadeh.tabazadeh-1@nasa.gov; katja.drdla-1@nasa.gov; m.e.hervig@gats-inc.com; stephen.eckermann@nrl.navy.mil; edward.v.browell@nasa.gov; legg@pixels.arc.nasa.gov; tfoschi@sfsu.edu NR 35 TC 20 Z9 20 U1 1 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD FEB 26 PY 2004 VL 109 IS D4 AR D04312 DI 10.1029/2003JD003846 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 803FK UT WOS:000220216800002 ER PT J AU Birn, J Schindler, K Hesse, M AF Birn, J Schindler, K Hesse, M TI Thin electron current sheets and their relation to auroral potentials SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article DE thin current sheets; Vlasov equilibrium; auroral potentials ID BIFURCATED CURRENT SHEET; BURSTY BULK FLOWS; PLASMA SHEET; MAGNETOTAIL; CONFIGURATIONS AB [1] Using the two-dimensional, steady-state Vlasov theory derived in a previous paper, we further investigate properties of thin current sheets that result from exact particle motion. The self-consistent quasi-neutral structure of thin current sheets generally requires the presence of an electric potential, which is constant along field lines. We establish that potential differences of up to the ion thermal potential kT(i)/e may be present when the current sheet thickness becomes comparable to or smaller than a typical ion Larmor radius. We further explore the possible association of thin current sheets with the perpendicular electric fields that are part of the U-shaped potential structures above auroral arcs. For sufficiently small scales, the converging perpendicular electric field corresponds to two oppositely directed thin Hall current sheets. We construct such double current sheet models and confirm that they result in potentials with the postulated shape and, for sufficiently small scales, in substantial potential differences ( in fractions of the ion thermal potential kT(i)/e). The formation of such double current sheets, found recently in simulations of an earthward collapsing entropy-depleted magnetic flux tube ("bubble''), may provide a further link between bursty bulk flows, bubbles, and auroral features. C1 Los Alamos Natl Lab, Space & Atmospher Sci Grp, Los Alamos, NM 87545 USA. Ruhr Univ Bochum, Inst Theoret Phys 4, D-44780 Bochum, Germany. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Birn, J (reprint author), Los Alamos Natl Lab, Space & Atmospher Sci Grp, MS D466, Los Alamos, NM 87545 USA. EM jbirn@lanl.gov; ks@tp4.ruhr-uni-bochum.de; hesse@gsfc.nasa.gov RI Hesse, Michael/D-2031-2012 NR 22 TC 48 Z9 48 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 FEB 26 PY 2004 VL 109 IS A2 AR A02217 DI 10.1029/2003JA010303 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 803GE UT WOS:000220218800004 ER PT J AU Palle, PV Ajello, J Bhardwaj, A AF Palle, PV Ajello, J Bhardwaj, A TI High-resolution far ultraviolet spectrum of electron-excited SO2 SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article DE Jovian satellites; airglow aurora; electron impact; ultraviolet emissions ID TRANSLATIONAL ENERGY-DISTRIBUTION; IMPACT DISSOCIATIVE EXCITATION; EMISSION CROSS-SECTIONS; GALILEO SPACECRAFT; IOS ATMOSPHERE; VACUUM ULTRAVIOLET; ATOMIC SULFUR; LINE-PROFILE; OXYGEN; H-2 AB [1] The high-resolution UV capabilities (lambda/Deltalambda = 10(5)) of the Hubble Space Telescope (HST) equipped with the Space Telescope Imaging Spectrograph (STIS) reflects a need for a high-resolution laboratory UV spectral data base for comparison with observation. For the purpose of interpreting the astronomical observations of Io by HST the electron-excited UV spectrum of SO2 gas has been studied from 800 - 1700 Angstrom at medium (lambda/Deltalambda similar to10(3)) and high resolution (lambda/Deltalambda similar to 5 x 10(4)). The far ultraviolet (FUV) laboratory spectrum consists entirely of S I, II and O I, II multiplets. From a measurement of the medium resolution spectrum at 1.5 Angstrom FWHM we are able to provide new detail in the 200 eVemission cross sections for all the FUV features. At 30 and 100 eV electron-impact energy we have measured high resolution emission spectra of the fine structure lines of the atomic multiplets at 1256 Angstrom from S II, at 1304 Angstrom from O I, 1479 Angstrom from S I and at 1429 Angstrom from S I at 100 eV electron-impact energy. At 100 eV electron-impact energy we compare the optically thin laboratory spectrum of the atomic multiplet S I at 1479 Angstrom with the model spectrum of electron excitation of atomic sulfur. In addition, we compare a HST STIS observation of Io with the G140M grating (FWHM similar to 0.5 Angstrom) at 1479 Angstrom with a laboratory spectrum after transmission through a layer of atomic S. We have also compared our laboratory spectrum to FUV observations by STIS reported by Roesler et al. [1999]. The relative intensities of the strongest lines of S I and O I are compared with the laboratory emission cross sections for SO2 near 40 eV (3 Ryd) electron energy. The Doppler line profiles of individual fine structure lines of atomic sulfur and oxygen were used to ascertain the kinetic energy distribution from dissociative excitation at 30 and 100 eV. At 100 eV electron- impact energy we find the kinetic energy distribution of the oxygen and sulfur atoms to be in the range of 2 eV to 3 eV. At 30 eV electron- impact energy we place an upper limit on the kinetic energy of sulfur and oxygen atoms as < 1 eV. We provide the first measurement of the O I] 1356 angstrom absolute excitation function and the estimate of the cross section ratio O I] 1356 angstrom/ 1304 angstrom as a function of energy. We establish the absolute cross section of O I 1304 angstrom as 2.3 +/- 0.5 x 10(-18) cm(2) at 100 eV and the estimated cross section of O I] 1356 angstrom as 2.1 +/- 1 x 10(-18) cm(2) at 100 eV. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Vikram Sarabhai Space Ctr, Space Phys Lab, Trivandrum 690522, Kerala, India. RP CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM jajello@jpl.nasa.gov NR 41 TC 6 Z9 6 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9380 EI 2169-9402 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD FEB 26 PY 2004 VL 109 IS A2 AR A02310 DI 10.1029/2003JA009828 PG 17 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 803GE UT WOS:000220218800001 ER PT J AU Mahesh, A Gray, MA Palm, SP Hart, WD Spinhirne, JD AF Mahesh, A Gray, MA Palm, SP Hart, WD Spinhirne, JD TI Passive and active detection of clouds: Comparisons between MODIS and GLAS observations SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID WATER-VAPOR; AEROSOL; AVHRR AB The Geoscience Laser Altimeter System ( GLAS), launched on board the Ice, Cloud and Land Elevation Satellite in January 2003 provides space-borne laser observations of atmospheric layers. GLAS provides opportunities to validate passive observations of the atmosphere for the first time from space with an active optical instrument. Data from the Moderate Resolution Imaging Spectroradiometers aboard the Terr and Aqua satellites are examined along with GLAS observations of cloud layers. In more than three-quarters of the cases, MODIS scene identification from spectral radiances agrees with GLAS. Disagreement between the two platforms is most significant over snow-covered surfaces in the northern hemisphere. Daytime clouds detected by GLAS are also more easily seen in the MODIS data as well, compared to observations made at night. These comparisons illustrate the capabilities of active remote sensing to validate and assess passive measurements, and also to complement them in studies of atmospheric layers. C1 NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. Univ Maryland Baltimore Cty, Goddard Earth Sci & Technol Ctr, Baltimore, MD 21228 USA. Sci Syst & Applicat Inc, Lanham, MD USA. RP Mahesh, A (reprint author), NASA, Goddard Space Flight Ctr, Atmospheres Lab, Code 912, Greenbelt, MD 20771 USA. EM mahesh@agnes.gsfc.nasa.gov NR 12 TC 23 Z9 23 U1 1 U2 5 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD FEB 25 PY 2004 VL 31 IS 4 AR L04108 DI 10.1029/2003GL018859 PG 5 WC Geosciences, Multidisciplinary SC Geology GA 803EY UT WOS:000220215600003 ER PT J AU Hall, TM Waugh, DW Haine, TWN Robbins, PE Khatiwala, S AF Hall, TM Waugh, DW Haine, TWN Robbins, PE Khatiwala, S TI Estimates of anthropogenic carbon in the Indian Ocean with allowance for mixing and time-varying air-sea CO2 disequilibrium SO GLOBAL BIOGEOCHEMICAL CYCLES LA English DT Article DE carbon; ocean; transport; mixing; age; Indian Ocean ID WATER MASS AGES; ATLANTIC-OCEAN; NORTH-ATLANTIC; WIND-SPEED; VENTILATION; CIRCULATION; THERMOCLINE; INCREASE; EXCHANGE; TRACERS AB [1] We apply to the Indian Ocean a novel technique to estimate the distribution, total mass, and net air-sea flux of anthropogenic carbon. Chlorofluorocarbon data are used to constrain distributions of transit times from the surface to the interior that are constructed to accommodate a range of mixing scenarios, from no mixing ( pure bulk advection) to strong mixing. The transit time distributions are then used to propagate to the interior the surface water history of anthropogenic carbon estimated in a way that includes temporal variation in CO2 air-sea disequilibrium. By allowing for mixing in transport and for variable air- sea disequilibrium, we remove two sources of positive bias common in other studies. We estimate that the anthropogenic carbon mass in the Indian Ocean was 14.3 - 20.5 Gt in 2000, and the net air- sea flux was 0.26 - 0.36 Gt/yr. The upper bound of this range, the no-mixing limit, generally coincides with previous studies, while the lower bound, the strong-mixing limit, is significantly below previous studies. C1 Columbia Univ, NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Johns Hopkins Univ, Dept Earth & Planetary Sci, Baltimore, MD 21218 USA. Univ Calif San Diego, Scripps Inst Oceanog, La Jolla, CA 92093 USA. Columbia Univ, Lamont Doherty Earth Observ, Palisades, NY 10964 USA. RP Hall, TM (reprint author), Columbia Univ, NASA, Goddard Inst Space Studies, 2880 Broadway, New York, NY 10025 USA. EM thall@giss.nasa.gov; waugh@jhu.edu; thomas.haine@jhu.edu; probbins@ucsd.edu; spk@ldeo.columbia.edu RI Waugh, Darryn/K-3688-2016 OI Waugh, Darryn/0000-0001-7692-2798 NR 36 TC 46 Z9 47 U1 0 U2 9 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0886-6236 J9 GLOBAL BIOGEOCHEM CY JI Glob. Biogeochem. Cycle PD FEB 25 PY 2004 VL 18 IS 1 AR GB1031 DI 10.1029/2003GB002120 PG 11 WC Environmental Sciences; Geosciences, Multidisciplinary; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Geology; Meteorology & Atmospheric Sciences GA 803FD UT WOS:000220216100003 ER PT J AU Whittenberger, JD Noebe, RD Darolia, R AF Whittenberger, JD Noebe, RD Darolia, R TI Elevated temperature creep deformation in solid solution strengthened < 001 > NiAl-3.6Ti single crystals SO MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING LA English DT Article DE NiAl; single crystal; creep; Cottrell-Jaswon model; activation energy ID ALLOYS; DIFFUSION; BEHAVIOR; INTERDIFFUSION; TRANSITION; 1000-K; PHASE; SIZE AB The 1100-1500 K slow plastic strain rate compressive properties of <0 0 1> oriented NiAl-3.6Ti single crystals have been measured, and the results suggests that two deformation processes exist. While the intermediate temperature/faster strain rate mechanism is uncertain, plastic flow at elevated temperature/slower strain rates in NiAl-3.6Ti appears to be controlled by solute drag as described by the Cottrell-Jaswon solute drag model for gliding b = a(0) <10 1> dislocations. While the calculated activation energy of deformation is much higher (similar to480 kJ/mol) than the activation energy for diffusion (similar to290 kJ/mol) used in the Cottrell-Jaswon creep model, a forced temperature-compensated power law fit using the activation energy for diffusion was able to adequately (>90%) predict the observed creep properties. Thus, we conclude that the rejection of a diffusion controlled mechanism cannot be simply based on a large numerical difference between the activation energies for deformation and diffusion. (C) 2003 Published by Elsevier B.V. C1 NASA, Glenn Res Ctr, Div Mat, Cleveland, OH 44135 USA. GE Co, Aircraft Engines, Cincinnati, OH 45215 USA. RP Whittenberger, JD (reprint author), NASA, Glenn Res Ctr, Div Mat, Lewis Field, Cleveland, OH 44135 USA. EM msea_jdw@yahoo.com NR 26 TC 11 Z9 11 U1 0 U2 2 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0921-5093 J9 MAT SCI ENG A-STRUCT JI Mater. Sci. Eng. A-Struct. Mater. Prop. Microstruct. Process. PD FEB 25 PY 2004 VL 367 IS 1-2 BP 143 EP 151 DI 10.1016/j.msea.2003.09.094 PG 9 WC Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering SC Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering GA 776RZ UT WOS:000189132200017 ER PT J AU Birn, J Dorelli, JC Hesse, M Schindler, K AF Birn, J Dorelli, JC Hesse, M Schindler, K TI Thin current sheets and loss of equilibrium: Three-dimensional theory and simulations SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article DE thin current sheets; substorm growth phase; substorm onset; catastrophe ID NEAR-EARTH MAGNETOTAIL; GROWTH-PHASE; MAGNETOSPHERIC SUBSTORMS; PLASMA SHEET; TAIL; DISRUPTION; MECHANISM; DYNAMICS; ONSET; FIELD AB [1] Using quasi-static equilibrium theory and three-dimensional MHD simulations, we confirm earlier two-dimensional results that finite boundary deformations of magnetotail equilibria can lead to large local current density enhancements, that is, the formation of thin current sheets. Equilibrium configurations that satisfy flux, entropy, and topology conservation cease to exist when the boundary deformations exceed critical limits. This provides a strong argument for onset of instability or the loss of equilibrium, regardless of the dissipation mechanism. Catastrophe points can be reached for relatively modest perturbations of the boundary. The most important internal property that influences the critical limit is the variation of the lobe magnetic field strength with distance from the Earth, related to the overall tail flaring. Stronger flaring, corresponding to a more rapid decrease of the lobe field with distance downtail, tends to stabilize the tail. That means such configurations require stronger perturbations to reach the critical limit or show less significant thinning and current density intensification for a given perturbation. Due to the nonlinearity of the tail response to the perturbations, the current intensification tends to be more localized than the perturbation. C1 Los Alamos Natl Lab, Los Alamos, NM 87545 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Ruhr Univ Bochum, Inst Theoret Phys 4, D-44780 Bochum, Germany. RP Birn, J (reprint author), Los Alamos Natl Lab, MS D466, Los Alamos, NM 87545 USA. EM jbirn@lanl.gov; john.dorelli@unh.edu; hesse@gsfc.nasa.gov; ks@tp4.ruhr-uni.bochum.de RI Dorelli, John/C-9488-2012; Hesse, Michael/D-2031-2012 NR 37 TC 17 Z9 17 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 FEB 24 PY 2004 VL 109 IS A2 AR A02215 DI 10.1029/2003JA010275 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 803GC UT WOS:000220218600005 ER PT J AU Meador, MAB Frimer, AA Johnston, JC AF Meador, MAB Frimer, AA Johnston, JC TI Reevaluation of tetrahydrophthalic anhydride as an end cap for improved oxidation resistance in addition polyimides SO MACROMOLECULES LA English DT Article ID DEGRADATION; POLYMERS; PRODUCTS; ACID; NMR AB Several substituted 1,2,3,6-tetrahydrophthalic anhydride end caps, including the 3-phenyl, 3-methoxy, 3-trimethylsilyloxy, and 3,6-diphenyl analogues, were synthesized via the Diels-Alder condensation of the corresponding butadienes and maleic anhydride. These anhydrides, as well as the commercially available 3-hydro and 4-methyl analogues, were each ground up together with methylenedianiline in a 2:1 ratio and heated gradually from 204 to 371 degreesC, with the thermolysis followed by NMR. Generally speaking, a transformation via monoimide to bisimide was observed in the lower temperature range, followed by competition between cross-linking and aromatization. We believe that this competition produces a substantial percentage of aromatic product, with the concomitant lowering of the relative amount of cross-linking and is responsible for both improved thermooxidative stability of tetrahydrophthalic end-capped polyimides and their substantial frangibility. The thermolysis of the tetrahydrophthalimides under an inert atmosphere dramatically lowers the amount of aromatization; hence, the mechanism for aromatization is an oxidative one. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. Bar Ilan Univ, Dept Chem, Ethel & David Resnick Chair Act Oxygen Chem, IL-52900 Ramat Gan, Israel. RP Meador, MAB (reprint author), NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. EM maryann.meador@nasa.gov OI Meador, Mary Ann/0000-0003-2513-7372 NR 27 TC 4 Z9 5 U1 1 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0024-9297 J9 MACROMOLECULES JI Macromolecules PD FEB 24 PY 2004 VL 37 IS 4 BP 1289 EP 1296 DI 10.1021/ma0353078 PG 8 WC Polymer Science SC Polymer Science GA 776AA UT WOS:000189091800018 ER PT J AU Galkin, IA Reinisch, BW Huang, XQ Benson, RF Fung, SF AF Galkin, IA Reinisch, BW Huang, XQ Benson, RF Fung, SF TI Automated diagnostics for resonance signature recognition on IMAGE/RPI plasmagrams SO RADIO SCIENCE LA English DT Article DE intelligent systems; radio sounding; Radio Plasma Imager ID ELECTRON-DENSITY; MAGNETIC-FIELD; RADIO EMISSIONS; CLASSIFICATION AB [1] The Radio Plasma Imager (RPI) aboard the IMAGE spacecraft probes plasma at both far and near ranges by means of radio sounding. The RPI plasmagrams, similar in their concept to the ground-based and topside ionograms, contain not only a variety of signatures pertaining to the remote plasma structures and boundaries, but also a suite of the local plasma resonances stimulated by the RPI radio transmissions. Detection and interpretation of the resonance signatures is a valuable diagnostic tool providing the actual electron density and magnetic field strength at the spacecraft location, which are needed for the accurate processing of the remote sensing information on the plasmagrams. The high volume of the RPI sounding data demanded the development of automated techniques for routine interpretation of the plasmagrams. This paper discusses a new method for the detection and interpretation of the resonance signatures in the RPI plasmagrams that employs pattern recognition techniques to localize the signatures and identifies them in relation to model-based resonances. C1 Univ Massachusetts Lowell, Ctr Atmospher Res, Lowell, MA 01854 USA. NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Space Phys Data Facil, Greenbelt, MD 20771 USA. RP Galkin, IA (reprint author), Univ Massachusetts Lowell, Ctr Atmospher Res, 600 Suffolk St, Lowell, MA 01854 USA. EM ivan_galkin@uml.edu RI Fung, Shing/F-5647-2012 NR 21 TC 4 Z9 4 U1 0 U2 0 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 FEB 24 PY 2004 VL 39 IS 1 AR RS1015 DI 10.1029/2003RS002921 PG 15 WC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications SC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications GA 803GL UT WOS:000220219500006 ER PT J AU Hajj, GA Wilson, BD Wang, C Pi, X Rosen, IG AF Hajj, GA Wilson, BD Wang, C Pi, X Rosen, IG TI Data assimilation of ground GPS total electron content into a physics-based ionospheric model by use of the Kalman filter SO RADIO SCIENCE LA English DT Article DE ionosphere; forecast; data assimilation; Kalman filter ID GLOBAL POSITIONING SYSTEM; LOWER ATMOSPHERE; TOMOGRAPHY; PROFILES; MIDDLE AB [1] A three-dimensional (3-D) Global Assimilative Ionospheric Model (GAIM) is currently being developed by a joint University of Southern California and Jet Propulsion Laboratory (JPL) team. To estimate the electron density on a global grid, GAIM uses a first-principles ionospheric physics model and the Kalman filter as one of its possible estimation techniques. Because of the large dimension of the state (i.e., electron density on a global 3-D grid), implementation of a full Kalman filter is not computationally feasible. Of the possible suboptimal implementations of the Kalman filter, we have chosen a band-limited Kalman filter where a full time propagation of the state error covariance is performed, but it is always kept sparse and banded. The effectiveness of ground GPS data for specifying the ionosphere is assessed by assimilating slant total electron content (TEC) data from 98 sites into the GAIM Kalman filter and validating the electron density field against independent measurements. A series of GAIM analyses are presented and validated by comparisons to JPL's global ionospheric maps (GIM) of vertical TEC (VTEC) and measurements from TOPEX. A statistical evaluation of GAIM and GIM against TOPEX VTEC indicates that GAIM accuracy is comparable or superior to GIM. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ So Calif, Dept Math, Los Angeles, CA 90089 USA. RP Hajj, GA (reprint author), Univ So Calif, Dept Math, Los Angeles, CA 90089 USA. EM george.hajj@jpl.nasa.gov; brian.d.wilson@jpl.nasa.gov; cwang@cams.usc.edu; xiaoqing.pi@jpl.nasa.gov; grosen@math.usc.edu NR 28 TC 48 Z9 50 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0048-6604 J9 RADIO SCI JI Radio Sci. PD FEB 24 PY 2004 VL 39 IS 1 AR RS1S05 DI 10.1029/2002RS002859 PG 17 WC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications SC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications GA 803GL UT WOS:000220219500003 ER PT J AU Nouvel, JF Herique, A Kofman, W Safaeinili, A AF Nouvel, JF Herique, A Kofman, W Safaeinili, A TI Radar signal simulation: Surface modeling with the Facet Method SO RADIO SCIENCE LA English DT Article DE surface modeling; Facet Method; radar signal ID MARS; TOPOGRAPHY AB [1] A major finding in exploration of Mars is the indication that a large quantity of water has been present on Mars. To discover the distribution of this quantity of water, the Mars Express spacecraft is carrying a spaceborne radar sounder, called Mars Advance Radar for Subsurface and Ionospheric Sounding (MARSIS), in order to map Mars subsurface dielectric characteristics. The returned radar echoes from Mars will contain both surface and subsurface reflection components, but the part of the signal we are interested in is the reflected signal from subsurface layers. To retrieve these weak deep echoes from the radar signal, a signal processing algorithm needs to be developed. In this paper, we present a computationally efficient radar signal simulation based on the use of the Facet Method as a surface modeling scheme. This simulator will be used to validate the MARSIS ground processing software and to support the interpretation of MARSIS data. The first step in the simulation algorithm definition is to model the Mars surface. Many surface modeling methods have been developed and can be found in the literature, but considering the fact that Mars surface is very smooth, the modeling algorithm we have developed uses the Facet Method. In this paper, we show that the Facet Method is an efficient scheme for modeling a relatively smooth surface, such as the Mars' surface. The instrument simulation we define makes strict reference to the MARSIS radar parameters; however, it may be used to model any radar sounder. C1 Univ Grenoble 1, Lab Planetol Grenoble, F-38041 Grenoble 9, France. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Nouvel, JF (reprint author), Univ Grenoble 1, Lab Planetol Grenoble, Bat D Phys,BP 53, F-38041 Grenoble 9, France. EM nouvel@obs.ujf-grenoble.fr; ali.safaeinili@jpl.nasa.gov RI Kofman, Wlodek/C-4556-2008; Herique, Alain/E-7210-2017 OI Herique, Alain/0000-0003-3699-883X NR 11 TC 36 Z9 40 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0048-6604 J9 RADIO SCI JI Radio Sci. PD FEB 24 PY 2004 VL 39 IS 1 AR RS1013 DI 10.1029/2003RS002903 PG 17 WC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications SC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications GA 803GL UT WOS:000220219500004 ER PT J AU Rodriguez-Gomez, D Darve, E Pohorille, A AF Rodriguez-Gomez, D Darve, E Pohorille, A TI Assessing the efficiency of free energy calculation methods SO JOURNAL OF CHEMICAL PHYSICS LA English DT Article ID HISTOGRAM ANALYSIS METHOD; MONTE-CARLO SIMULATIONS; WATER-HEXANE INTERFACE; MOLECULAR-DYNAMICS; NONEQUILIBRIUM MEASUREMENTS; POTENTIAL FUNCTIONS; CANONICAL ENSEMBLE; BINDING AFFINITIES; PHASE-SPACE; EQUILIBRIUM AB The efficiencies of two recently developed methods for calculating free energy changes along a generalized coordinate in a system are discussed in the context of other, related approaches. One method is based on Jarzynski's identity [Phys. Rev. Lett. 78, 2690 (1997)]. The second method relies on thermodynamic integration of the average force and is called the adaptive biasing force method [Darve and Pohorille, J. Chem. Phys. 115, 9169 (2001)]. Both methods are designed such that the system evolves along the chosen coordinate(s) without experiencing free energy barriers and they require calculating the instantaneous, unconstrained force acting on this coordinate using the formula derived by Darve and Pohorille. Efficiencies are analyzed by comparing analytical estimates of statistical errors and by considering two numerical examples-internal rotation of hydrated 1,2-dichloroethane and transfer of fluoromethane across a water-hexane interface. The efficiencies of both methods are approximately equal in the first but not in the second case. During transfer of fluoromethane the system is easily driven away from equilibrium and, therefore, the performance of the method based on Jarzynski's identity is poor. (C) 2004 American Institute of Physics. C1 Stanford Univ, Dept Mech Engn, Stanford, CA 94305 USA. NASA, Ames Res Ctr, Exobiol Branch, Stanford, CA 94305 USA. NASA, Ames Res Ctr, Ctr Turbulence Res, Stanford, CA 94305 USA. Univ Calif San Francisco, Dept Pharmaceut Chem, San Francisco, CA 94143 USA. RP Stanford Univ, Dept Mech Engn, Stanford, CA 94305 USA. EM davidrg@stanford.edu; darve@stanford.edu; dpohorill@raphael.arc.nasa.gov NR 52 TC 144 Z9 147 U1 3 U2 37 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 FEB 22 PY 2004 VL 120 IS 8 BP 3563 EP 3578 DI 10.1063/1.1642607 PG 16 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 776VH UT WOS:000189139700006 PM 15268518 ER PT J AU Fiore, A Jacob, DJ Liu, H Yantosca, RM Fairlie, TD Li, Q AF Fiore, A Jacob, DJ Liu, H Yantosca, RM Fairlie, TD Li, Q TI Variability in surface ozone background over the United States: Implications for air quality policy (vol 108, pg 4787, 2003) SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Correction DE background ozone; air quality; hemispheric pollution C1 Harvard Univ, Dept Earth & Planetary Sci, Cambridge, MA 02138 USA. Harvard Univ, Div Engn & Appl Sci, Cambridge, MA 02138 USA. RP Fiore, A (reprint author), NASA, Langley Res Ctr, Hampton, VA 23665 USA. EM t.d.fairlie@larc.nasa.gov RI Liu, Hongyu/A-5867-2008; Yantosca, Robert/F-7920-2014 OI Yantosca, Robert/0000-0003-3781-1870 NR 2 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 FEB 21 PY 2004 VL 109 IS D4 AR D04308 DI 10.1029/2004JD004567 PG 1 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 780HG UT WOS:000189373800009 ER PT J AU Gu, GJ Adler, RF Huffman, GJ Curtis, S AF Gu, GJ Adler, RF Huffman, GJ Curtis, S TI African easterly waves and their association with precipitation SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE African easterly waves; tropical convection ID SYNOPTIC-SCALE DISTURBANCES; WEST-AFRICA; TROPICAL ATLANTIC; NORTHERN SUMMER; PART I; VARIABILITY; REANALYSES; NCEP/NCAR; GATE; ITCZ AB Summer tropical synoptic-scale waves over West Africa are quantified by the 850 mb meridional wind component from the National Centers for Environmental Prediction/National Center for Atmospheric Research reanalysis project. Their relationships with surface precipitation patterns are explored by applying the data from the Tropical Rainfall Measuring Mission satellite in combination with other satellite observations during 1998-2002. Evident wavelet spectral power peaks are seen within a period of 2.5-6 days in both meridional wind and precipitation. The most intense wave signals in meridional wind are concentrated along 15degreesN-25degreesN. Wave signals in precipitation and corresponding wavelet cross-spectral signals between these two variables, however, are primarily located at 5degreesN-15degreesN, the latitudes of major summer rain events. Southerly wind perturbations tend to lag (lead) precipitation signals south (north) of 15degreesN. In some cases either an in-phase or out-of-phase relationship can even be found, suggesting two distinct relationships between the waves and convection. Moreover, the lagging relationship (and/or the out-of-phase tendency) is only observed south of 15degreesN during July-September, indicating a strong seasonal preference. This phase relationship is generally consistent with the horizontal wave structures from a composite analysis. C1 NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. Sci Syst & Applicat Inc, Lanham, MD USA. Univ Maryland Baltimore Cty, Joint Ctr Earth Syst Technol, Baltimore, MD 21228 USA. Univ Maryland Baltimore Cty, Goddard Earth Sci & Technol Ctr, Baltimore, MD 21228 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; adler@agnes.gsfc.nasa.gov; huffman@agnes.gsfc.nasa.gov; curtisw@mail.ecu.edu RI Curtis, Scott/C-1115-2013; Huffman, George/F-4494-2014 OI Huffman, George/0000-0003-3858-8308 NR 33 TC 29 Z9 30 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 FEB 21 PY 2004 VL 109 IS D4 AR D04101 DI 10.1029/2003JD003967 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 780HG UT WOS:000189373800004 ER PT J AU Mallet, M Roger, JC Despiau, S Putaud, JP Dubovik, O AF Mallet, M Roger, JC Despiau, S Putaud, JP Dubovik, O TI A study of the mixing state of black carbon in urban zone SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE aerosol; black carbon; mixing state ID AEROSOL OPTICAL-PROPERTIES; SKY RADIANCE MEASUREMENTS; MID-ATLANTIC COAST; ANTHROPOGENIC SULFATE; ATMOSPHERIC AEROSOLS; UNITED-STATES; SOOT AEROSOL; ABSORPTION; PARTICLES; MODEL AB The knowledge of the mixing state of black carbon particle with other aerosol species is critical for adequate simulations of the direct radiative effect of black carbon particles and its effect on climate. This paper reports the investigation of the mixing state of black carbon aerosol in the urban zone. The study uses a combination of in situ and ground-based remote sensing observations conducted during the ESCOMPTE experiment, which took place in industrialized region in France in summer of 2001. The criteria we used for identifying mixing state relies on the known enhancement of absorption for aerosol composed by internal versus external mixtures of black carbon with weakly absorbing aerosol components. First, using in situ aerosol data, we performed Mie computations and reconstructed the single scattering albedo of aerosol for the two different mixing assumptions: black carbon mixed externally or internally with other aerosol species. Then, we compared the obtained values omega(o,int) and omega(o,ext) with the retrievals of omega(o) from independent AERONET Sun-photometric measurements. The aerosol single scattering albedo (omega(o,aer.)) derived from the AERONET photometer observations (with the mean value equal to 0.84 +/- 0.04) was found to be close to omega(o,ext) reconstructed from in situ observation under assumptions of external mixture. This similarity between AERONET values and external mixture simulations was observed during all the days studied. Our conclusion on external mixture of black carbon aerosol with other particles in urban zone during ESCOMPTE (close to the pollution source) is coherent with observations made during other independent studies reported in a number of recent publications. C1 Univ Toulon & Var, LEPI, F-83162 La Valette Du Var, France. Univ Littoral Cote Opale, LOCL, MREN, ELICO, F-62930 Dunkerque, France. Commiss European Communities, Joint Res Ctr, I-21020 Ispra, Italy. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Mallet, M (reprint author), Univ Toulon & Var, LEPI, F-83162 La Valette Du Var, France. EM mmallet@univ-tln.fr; jc@mren2.univ-littoral.fr; despiau@univ-tln.fr; jean.putaud@jrc.it; dubovik@aeronet.gsfc.nasa.gov RI Dubovik, Oleg/A-8235-2009 OI Dubovik, Oleg/0000-0003-3482-6460 NR 39 TC 43 Z9 44 U1 3 U2 13 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 FEB 21 PY 2004 VL 109 IS D4 AR D04202 DI 10.1029/2003JD003940 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 780HG UT WOS:000189373800003 ER PT J AU Miller, RL Tegen, I Perlwitz, J AF Miller, RL Tegen, I Perlwitz, J TI Surface radiative forcing by soil dust aerosols and the hydrologic cycle SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Review DE dust aerosol; radiative forcing; hydrologic cycle ID LAST GLACIAL MAXIMUM; GENERAL-CIRCULATION MODEL; MINERAL DUST; SAHARAN DUST; OPTICAL-THICKNESS; NORTH-ATLANTIC; CLIMATE-CHANGE; INTERANNUAL VARIABILITY; TROPOSPHERIC AEROSOLS; ATMOSPHERIC TRANSPORT AB For absorbing aerosols like soil (or "mineral'') dust, radiative forcing at the surface differs substantially from the value at the top of the atmosphere (TOA). The climate response depends not only upon the TOA forcing, but its difference with respect to the surface value, which represents radiative heating within the atmosphere. Surface forcing alters evaporation and the hydrologic cycle, which feeds back upon the aerosol burden through the efficiency of wet deposition. We calculate the surface forcing by soil dust aerosols and its global sensitivity by varying aspects of the dust distribution that are poorly constrained by observations. Ignorance of the global dust burden corresponds to a forcing uncertainty of over a factor of two, with smaller uncertainties due to imprecise knowledge of particle optical properties and the particle size distribution. While global evaporation and precipitation are reduced in response to surface radiative forcing by dust, precipitation increases locally over desert regions, so that dust emission can act as a negative feedback to desertification. The effect of the global reduction in precipitation is to lengthen the particle lifetime by reducing the efficiency of wet deposition, representing a positive feedback upon the global dust burden. For the current climate, we calculate the reduction in wet deposition by dust radiative forcing and find that the aerosol burden is increased only modestly. However, the global dust burden and associated radiative forcing are substantially higher during glacial climates, so that the amplification of the dust load by this feedback is larger. By extrapolating from its radiative forcing in the current climate, we estimate that dust reduces precipitation during glacial times by as much as half the reduction due to the colder climate alone. C1 Columbia Univ, Dept Appl Phys, New York, NY 10025 USA. NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Max Planck Inst Biogeochem, D-07701 Jena, Germany. RP Columbia Univ, Dept Appl Phys, Armstrong 550, New York, NY 10025 USA. EM rlm15@columbia.edu; itegen@bgc-jena.mpg.de; jperlwitz@giss.nasa.gov RI Miller, Ron/E-1902-2012 NR 108 TC 178 Z9 187 U1 5 U2 32 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 FEB 21 PY 2004 VL 109 IS D4 AR D04203 DI 10.1029/2003JD004085 PG 24 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 780HG UT WOS:000189373800006 ER PT J AU Koehne, J Li, J Cassell, AM Chen, H Ye, Q Ng, HT Han, J Meyyappan, M AF Koehne, J Li, J Cassell, AM Chen, H Ye, Q Ng, HT Han, J Meyyappan, M TI The fabrication and electrochemical characterization of carbon nanotube nanoelectrode arrays SO JOURNAL OF MATERIALS CHEMISTRY LA English DT Article ID PROTEIN ELECTROCHEMISTRY; ELECTRON-TRANSFER; SINGLE MOLECULES; DNA ANALYSIS; ENSEMBLES; DIMENSIONS; BRIDGES AB We report a novel approach for the fabrication of nanoelectrode arrays using vertically aligned multi-walled carbon nanotubes (MWCNTs) embedded within a SiO2 matrix. Cyclic voltammetry and pulse voltammetry are employed to characterize the electrochemical properties of the MWCNT array. The unique graphitic structure of the novel MWCNT nanoelectrodes is compared with model systems such as highly oriented pyrolytic graphite and glassy carbon electrodes. Low-density MWCNT nanoelectrode arrays display independent nanoelectrode behavior showing diffusion-limited steady-state currents in cyclic voltammetry over a wide range of scan rates. Electroactive species can be detected at concentrations as low as a few nM. In addition, ultrasensitive DNA/RNA sensors are demonstrated using the low-density MWCNT arrays with selectively functionalized oligonucleotide probes. This platform can be widely used in analytical applications as well as fundamental electrochemical studies. C1 NASA, Ames Res Ctr, Ctr Nanotechnol, Moffett Field, CA 94035 USA. RP Li, J (reprint author), NASA, Ames Res Ctr, Ctr Nanotechnol, Moffett Field, CA 94035 USA. EM jli@mail.arc.nasa.gov RI Li, Jun/H-7771-2013 OI Li, Jun/0000-0002-3689-8946 NR 52 TC 155 Z9 158 U1 4 U2 45 PU ROYAL SOC CHEMISTRY PI CAMBRIDGE PA THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND SN 0959-9428 EI 1364-5501 J9 J MATER CHEM JI J. Mater. Chem. PD FEB 21 PY 2004 VL 14 IS 4 BP 676 EP 684 DI 10.1039/b311728f PG 9 WC Chemistry, Physical; Materials Science, Multidisciplinary SC Chemistry; Materials Science GA 803IF UT WOS:000220224100033 ER PT J AU Rauch, EM Millonas, MM AF Rauch, EM Millonas, MM TI The role of trans-membrane signal transduction in turing-type cellular pattern formation SO JOURNAL OF THEORETICAL BIOLOGY LA English DT Article DE turing pattern; signal transduction; morphogen; pattern formation; morphogenesis; reaction-diffusion ID EQUAL DIFFUSION-COEFFICIENTS; DIFFERENTIAL FLOW; CHEMICAL-PATTERN; MECHANISMS; SYSTEM AB The Turing mechanism (Phil. Trans. R. Soc. B 237 (1952) 37) for the production of a broken spatial symmetry in an initially homogeneous system of reacting and diffusing Substances has attracted much interest as a potential model for certain aspects of morphogenesis (Models of Biological Pattern Formation, Academic Press, London, 1982; Nature 376 (1995) 765) Such as pre-patterning in the embryo. The two features necessary for the formation of Turing patterns are short-range autocatalysis and longrange inhibition (Kybernetik 12 (1972) 30) which usually only Occur when the diffusion rate of the inhibitor is significantly greater than that of the activator. This observation has sometimes been used to cast doubt on applicability of the Turing mechanism to cellular patterning since many messenger molecules that diffuse between cells do so at more-or-less similar rates. Here we show that Turing-type patterns will be able to robustly form under a wide variety of realistic physiological conditions though plausible mechanisms of intra-cellular chemical communication without relying on differences in diffusion rates. In the mechanism we propose, reactions Occur within cells. Signal transduction leads to the production of messenger molecules, which diffuse between cells at approximately equal rates, Coupling the reactions occurring in different cells. These mechanisms also suggest how this process can be controlled in a rather precise way by the genetic machinery of the cell. (C) 2003 Published by Elsevier Ltd. C1 MIT, Comp Sci & Artificial Intelligence Lab, Cambridge, MA 02139 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP MIT, Comp Sci & Artificial Intelligence Lab, 200 Technol Sq,Room 434, Cambridge, MA 02139 USA. EM rauch@ai.mit.edu NR 18 TC 29 Z9 30 U1 0 U2 3 PU ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD PI LONDON PA 24-28 OVAL RD, LONDON NW1 7DX, ENGLAND SN 0022-5193 EI 1095-8541 J9 J THEOR BIOL JI J. Theor. Biol. PD FEB 21 PY 2004 VL 226 IS 4 BP 401 EP 407 DI 10.1016/j.jtbi.2003.09.018 PG 7 WC Biology; Mathematical & Computational Biology SC Life Sciences & Biomedicine - Other Topics; Mathematical & Computational Biology GA 773ZD UT WOS:000188954500004 PM 14759646 ER PT J AU Palunas, P Teplitz, HI Francis, PJ Williger, GM Woodgate, BE AF Palunas, P Teplitz, HI Francis, PJ Williger, GM Woodgate, BE TI The distribution of Ly alpha-emitting galaxies at z=2.38 SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmology : observations; galaxies : evolution; galaxies : fundamental parameters ID LYMAN-BREAK GALAXIES; HUBBLE DEEP FIELD; STAR-FORMING GALAXIES; HIGH-REDSHIFT; COOLING RADIATION; DISK GALAXIES; PROTO-CLUSTER; RADIO GALAXY; Z-SIMILAR-TO-3; SCALE AB We present the detection of 34 Lyalpha emission-line galaxy candidates in a 80 x 80 x 60 comoving Mpc region surrounding the known z = 2.38 galaxy cluster J2143-4423. The space density of Lyalpha emitters is comparable to that found by Steidel et al. when targeting a cluster at redshift 3.09, which is a factor of 5.8 +/- 2.5 greater than that found by field samples at similar redshifts. The distribution of these galaxy candidates contains several 5-10 Mpc scale voids. We compare our observations with mock catalogs derived from the VIRGO consortium LambdaCDM n-body simulations. Fewer than 1% of the mock catalogs contain voids as large as we observe. Our observations thus tentatively suggest that the galaxy distribution at redshift 2.38 contains larger voids than predicted by current models. Three of the candidate galaxies and one previously discovered galaxy have the large luminosities and extended morphologies of "Lyalpha blobs.'' C1 Univ Texas, McDonald Observ, Austin, TX 78712 USA. CALTECH, Spitzer Sci Ctr, Pasadena, CA 91125 USA. Australian Natl Univ, Res Sch Astron & Astrophys, Canberra, ACT 0200, Australia. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Johns Hopkins Univ, Baltimore, MD 21218 USA. RP Palunas, P (reprint author), Univ Texas, McDonald Observ, Austin, TX 78712 USA. RI Woodgate, Bruce/D-2970-2012 NR 58 TC 83 Z9 83 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 FEB 20 PY 2004 VL 602 IS 2 BP 545 EP 554 DI 10.1086/381145 PN 1 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 779ZK UT WOS:000189343700001 ER PT J AU Barris, BJ Tonry, JL Blondin, S Challis, P Chornock, R Clocchiatti, A Filippenko, AV Garnavich, P Holland, ST Jha, S Kirshner, RP Krisciunas, K Leibundgut, B Li, WD Matheson, T Miknaitis, G Riess, AG Schmidt, BP Smith, RC Sollerman, J Spyromilio, J Stubbs, CW Suntzeff, NB Aussel, H Chambers, KC Connelley, MS Donovan, D Henry, JP Kaiser, N Liu, MC Martin, EL Wainscoat, RJ AF Barris, BJ Tonry, JL Blondin, S Challis, P Chornock, R Clocchiatti, A Filippenko, AV Garnavich, P Holland, ST Jha, S Kirshner, RP Krisciunas, K Leibundgut, B Li, WD Matheson, T Miknaitis, G Riess, AG Schmidt, BP Smith, RC Sollerman, J Spyromilio, J Stubbs, CW Suntzeff, NB Aussel, H Chambers, KC Connelley, MS Donovan, D Henry, JP Kaiser, N Liu, MC Martin, EL Wainscoat, RJ TI Twenty-three high-redshift supernovae from the Institute for Astronomy Deep Survey: Doubling the supernova sample at z > 0.7 SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmological parameters; distance scale; galaxies : distances and redshifts; supernovae : general ID HUBBLE-SPACE-TELESCOPE; DIGITAL SKY SURVEY; SOUTHERN SPECTROPHOTOMETRIC STANDARDS; FARTHEST KNOWN SUPERNOVA; BVRI LIGHT CURVES; IA SUPERNOVAE; LOCKMAN-HOLE; ACCELERATING UNIVERSE; COSMOLOGICAL CONSTANT; INTERGALACTIC MEDIUM AB We present photometric and spectroscopic observations of 23 high-redshift supernovae (SNe) spanning a range of z = 0.34-1.03, nine of which are unambiguously classified as Type Ia. These SNe were discovered during the IfA Deep Survey, which began in 2001 September and observed a total of 2.5 deg(2) to a depth of approximately m approximate to 25-26 in RIZ over 9-17 visits, typically every 1-3 weeks for nearly 5 months, with additional observations continuing until 2002 April. We give a brief description of the survey motivations, observational strategy, and reduction process. This sample of 23 high-redshift SNe includes 15 at z greater than or equal to 0.7, doubling the published number of objects at these redshifts, and indicates that the evidence for acceleration of the universe is not due to a systematic effect proportional to redshift. In combination with the recent compilation of Tonry et al. (2003), we calculate cosmological parameter density contours that are consistent with the flat universe indicated by the cosmic microwave background (Spergel et al. 2003). Adopting the constraint that Omega(total) = 1.0, we obtain best-fit values of (Omega(m), Omega(Lambda)) = (0.33, 0.67) using 22 SNe from this survey augmented by the literature compilation. We show that using the empty-beam model for gravitational lensing does not eliminate the need for Omega(Lambda) > 0. Experience from this survey indicates great potential for similar large-scale surveys while also revealing the limitations of performing surveys for z > 1 SNe from the ground. C1 Univ Hawaii, Inst Astron, Honolulu, HI 96822 USA. European So Observ, D-85748 Garching, Germany. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA. Pontificia Univ Catolica Chile, Dept Astron & Astrofis, Santiago 22, Chile. Univ Notre Dame, Dept Phys, Notre Dame, IN 46556 USA. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. Cerro Tololo Interamer Observ, La Serena, Chile. Las Campanas Observ, La Serena, Chile. Univ Washington, Dept Astron, Seattle, WA 98195 USA. Space Telescope Sci Inst, Baltimore, MD 21218 USA. Australian Natl Univ, Res Sch Astron & Astrophys, Weston 2611, Australia. AlbaNova, Stockholm Observ, SE-10691 Stockholm, Sweden. RP Barris, BJ (reprint author), Univ Hawaii, Inst Astron, 2680 Woodlawn Dr, Honolulu, HI 96822 USA. EM barris@ifa.hawaii.edu; jt@ifa.hawaii.edu; sblondin@eso.org; pchallis@cfa.harvard.edu; rchornock@astro.berkeley.edu; aclocchi@astro.puc.cl; alex@astroberkeley.edu; pgarnavi@miranda.phys.nd.edu; sholland@milkyway.gsfc.nasa.gov; sjha@astro.berkeley.edu; kirshner@cfa.harvard.edu; kkrisciunas@noao.edu; bleibund@eso.org; weidong@astro.berkeley.edu; tmatheson@cfa.harvard.edu; gm@u.washington.edu; ariess@stsci.edu; brian@mso.anu.edu.au; csmith@ctio.noao.edu; jesper@astro.su.se; jspyromi@eso.org; stubbs@astro.washington.edu; nsuntzeff@noao.edu; aussel@ifa.hawaii.edu; chambers@ifa.hawaii.edu; msc@galileo.ifa.hawaii.edu; donovan@ifa.hawaii.edu; henry@ifa.hawaii.edu; kaiser@ifa.hawaii.edu; liu@ifa.hawaii.edu; ege@ifa.hawaii.edu; rjw@ifa.hawaii.edu RI Stubbs, Christopher/C-2829-2012; OI Stubbs, Christopher/0000-0003-0347-1724; Sollerman, Jesper/0000-0003-1546-6615; Chambers, Kenneth /0000-0001-6965-7789; Schmidt, Brian/0000-0002-8538-9195 NR 96 TC 364 Z9 366 U1 0 U2 4 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD FEB 20 PY 2004 VL 602 IS 2 BP 571 EP 594 DI 10.1086/381122 PN 1 PG 24 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 779ZK UT WOS:000189343700004 ER PT J AU Romano, P Mathur, S Turner, TJ Kraemer, SB Crenshaw, DM Peterson, BM Pogge, RW Brandt, WN George, IM Horne, K Kriss, GA Netzer, H Shemmer, O Wamsteker, W AF Romano, P Mathur, S Turner, TJ Kraemer, SB Crenshaw, DM Peterson, BM Pogge, RW Brandt, WN George, IM Horne, K Kriss, GA Netzer, H Shemmer, O Wamsteker, W TI The spectral energy distribution and emission-line properties of the narrow-line Seyfert 1 galaxy Arakelian 564 SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : active; galaxies : individual (Arakelian 564); galaxies : nuclei; galaxies : Seyfert ID ACTIVE GALACTIC NUCLEI; X-RAY-PROPERTIES; SPECTROSCOPIC-EXPLORER-OBSERVATIONS; MASS-LUMINOSITY RELATIONS; ASCA OBSERVATIONS; ULTRAVIOLET EXTINCTION; ACCRETION DISKS; SPACE-TELESCOPE; TON S180; NGC 5548 AB We present the intrinsic spectral energy distribution ( SED) of the narrow-line Seyfert 1 galaxy (NLS1) Ark 564, constructed with contemporaneous data obtained during a multiwavelength, multisatellite observing campaign in 2000 and 2001. We compare this SED with that of the NLS1 Ton S180 and with those obtained for broad-line Seyfert 1 galaxies to infer how the relative accretion rates vary among the Seyfert 1 population. Although the peak of the SED is not well constrained, in our parameterization most of the energy of this object is emitted in the 10-100 eV regime, constituting roughly half of the emitted energy in the optical/X-ray ranges. This is consistent with a primary spectral component peaking in the extreme-UV/soft X-ray band and with disk-corona models, hence high accretion rates. Indeed, we estimate that. m approximate to 1. We also address the issue of the energy budget in this source by examining the emission lines observed in its spectrum, and we constrain the physical properties of the line-emitting gas through photoionization modeling. The available data suggest that the line-emitting gas is characterized by log n approximate to 11 and log U approximate to 0 and is stratified around log U approximate to 0. Our estimate of the radius of the Hbeta-emitting region R(BLR)(Hbeta) approximate to 10 +/- 2 lt-days is consistent with the R(BLR)(Hbeta)-luminosity relationships found for Seyfert 1 galaxies, which indicates that the narrowness of the emission lines in this NLS1 is not due to the broad-line region being relatively farther away from the central mass than in broad-line Seyfert 1 galaxies of comparable luminosity. We also find evidence for supersolar metallicity in this NLS1. We show that the emission lines are not good diagnostics for the underlying SEDs and that the absorption line studies offer a far more powerful tool to determine the ionizing continuum of active galactic nuclei, especially if one is comparing the lower and higher ionization lines. C1 Ohio State Univ, Dept Astron, Columbus, OH 43210 USA. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. Univ Maryland Baltimore Cty, Dept Phys, Joint Ctr Astrophys, Baltimore, MD 21250 USA. NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. Catholic Univ Amer, Greenbelt, MD 20771 USA. Georgia State Univ, Dept Phys & Astron, Atlanta, GA 30303 USA. Penn State Univ, Dept Astron & Astrophys, University Pk, PA 16802 USA. Univ St Andrews, Sch Phys & Astron, St Andrews KY16 9SS, Fife, Scotland. Space Telescope Sci Inst, Baltimore, MD 21218 USA. Tel Aviv Univ, Raymond & Beverly Sackler Fac Exact Sci, Wise Observ, IL-69978 Tel Aviv, Israel. Tel Aviv Univ, Sch Phys & Astron, IL-69978 Tel Aviv, Israel. European Space Agcy, Madrid 28080, Spain. RP Romano, P (reprint author), Osserv Astron Brera, INAF, I-23807 Merate, LC, Italy. EM romano@merate.mi.astro.it RI Brandt, William/N-2844-2015; OI Brandt, William/0000-0002-0167-2453; Romano, Patrizia/0000-0003-0258-7469; Shemmer, Ohad/0000-0003-4327-1460 NR 79 TC 32 Z9 32 U1 0 U2 3 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 FEB 20 PY 2004 VL 602 IS 2 BP 635 EP 647 DI 10.1086/381235 PN 1 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 779ZK UT WOS:000189343700008 ER PT J AU Reeves, JN Nandra, K George, IM Pounds, KA Turner, TJ Yaqoob, T AF Reeves, JN Nandra, K George, IM Pounds, KA Turner, TJ Yaqoob, T TI The XMM-Newton iron line profile of NGC 3783 SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : active; galaxies : individual (NGC 3783); galaxies : Seyfert; X-rays : galaxies ID ACTIVE GALACTIC NUCLEI; SEYFERT-1 GALAXY NGC-5548; X-RAY REFLECTION; EMISSION-LINE; BLACK-HOLE; IONIZED-GAS; GRATING SPECTROSCOPY; ASCA OBSERVATIONS; ABSORPTION-LINES; ACCRETION DISK AB We report on observations of the iron K line in the nearby Seyfert 1 galaxy, NGC 3783, obtained in a long, twoorbit (similar to 240 ks) XMM-Newton observation. The line profile obtained exhibits two strong narrow peaks at 6.4 and 7.0 keV, with measured line equivalent widths of 120 and 35 eV, respectively. The 6.4 keV emission is the Kalpha line from near neutral Fe, while the 7.0 keV feature probably originates from a blend of the neutral Fe Kalpha line and the hydrogen-like line of Fe at 6.97 keV. The relatively narrow velocity width of the Kalpha line (less than or similar to5000 km s(-1)), its lack of response to the continuum emission on short timescales, and the detection of a neutral Compton reflection component are all consistent with a distant origin in Compton-thick matter such as the putative molecular torus. A strong absorption line from highly ionized iron (at 6.67 keV) is detected in the time-averaged iron line profile, while the depth of the feature appears to vary with time, being strongest when the continuum flux is higher. The iron absorption line probably arises from the highest ionization component of the known warm absorber in NGC 3783, with an ionization of log xi similar to 3 and column density of N-H similar to 5 x 10(22) cm(-2) and may originate from within 0.1 pc of the nucleus. A weak red wing to the iron K line profile is also detected below 6.4 keV. However, when the effect of the highly ionized warm absorber on the underlying continuum is taken into account, the requirement for a relativistic iron line component from the inner disk is reduced. C1 NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. Univ Space Res Assoc, Columbia, MD 21044 USA. Univ Maryland, Joint Ctr Astrophys, Baltimore, MD 21250 USA. Univ London Imperial Coll Sci Technol & Med, Blackett Lab, Astrophys Grp, London SW7 2BW, England. Univ Maryland, Joint Ctr Astrophys, Baltimore, MD 21250 USA. Univ Leicester, Xray & Observat Astron Grp, Leicester LE1 7RH, Leics, England. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. RP Reeves, JN (reprint author), NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Code 662,Greenbelt Rd, Greenbelt, MD 20771 USA. EM jnr@milkyway.gsfc.nasa.gov NR 59 TC 109 Z9 111 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 FEB 20 PY 2004 VL 602 IS 2 BP 648 EP 658 DI 10.1086/381091 PN 1 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 779ZK UT WOS:000189343700009 ER PT J AU Watson, AM Stapelfeldt, KR AF Watson, AM Stapelfeldt, KR TI The visible and near-infrared dust opacity law in the HH 30 circumstellar disk SO ASTROPHYSICAL JOURNAL LA English DT Article DE circumstellarmatter; planetary systems : protoplanetary disks; stars : individual (HH30); stars : pre-main-sequence ID T-TAURI STARS; SPECTRAL ENERGY-DISTRIBUTION; ON-ORBIT PERFORMANCE; ACCRETION DISKS; YOUNG OBJECTS; GRAIN-GROWTH; HH 30; PROTOPLANETARY DISK; SCATTERED-LIGHT; IRRADIATION AB We present new images of the scattered-light disk around HH30 at 0.44 and 0.81 mum. We model these images and an existing 2.04 mum image by using a multiple-scattering code, varying and fitting for the disk parameters and the dust opacity ratios at these wavelengths. A wide range of different disk geometries provide adequate fits to the data; there is no single best-fit geometry. In particular, the fits cannot resolve the ambiguity between the power-law indices in surface density and scale height. On the other hand, the inclination, opacity-mass product, scale height, and to a lesser degree the extinction to the star are relatively tightly constrained. Despite the ambiguity in geometry, we conclude that the dust opacity in the scattering layers of the outer parts of the HH 30 circumstellar disk drops from 0.44 to 2.04 mum, but by less than in the low-density ISM. The median fit shows a drop by a factor of less than 2. This result is robust to reasonable changes in the disk density distribution. It suggests that moderate grain growth has occurred but that small grains still dominate the visible and near-infrared opacity. C1 Univ Nacl Autonoma Mexico, Ctr Radioastron & Astrofis, Morelia 58089, Michoacan, Mexico. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Watson, AM (reprint author), Univ Nacl Autonoma Mexico, Ctr Radioastron & Astrofis, Apartado Postal 3-72, Morelia 58089, Michoacan, Mexico. RI Stapelfeldt, Karl/D-2721-2012 NR 38 TC 27 Z9 27 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD FEB 20 PY 2004 VL 602 IS 2 BP 860 EP 874 DI 10.1086/381142 PN 1 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 779ZK UT WOS:000189343700025 ER PT J AU Sakamoto, T Lamb, DQ Graziani, C Donaghy, TQ Suzuki, M Ricker, G Atteia, JL Kawai, N Yoshida, A Shirasaki, Y Tamagawa, T Torii, K Matsuoka, M Fenimore, EE Galassi, M Tavenner, T Doty, J Vanderspek, R Crew, GB Villasenor, J Butler, N Prigozhin, G Jernigan, JG Barraud, C Boer, M Dezalay, JP Olive, JF Hurley, K Levine, A Monnelly, G Martel, F Morgan, E Woosley, SE Cline, T Braga, J Manchanda, R Pizzichini, G Takagishi, K Yamauchi, M AF Sakamoto, T Lamb, DQ Graziani, C Donaghy, TQ Suzuki, M Ricker, G Atteia, JL Kawai, N Yoshida, A Shirasaki, Y Tamagawa, T Torii, K Matsuoka, M Fenimore, EE Galassi, M Tavenner, T Doty, J Vanderspek, R Crew, GB Villasenor, J Butler, N Prigozhin, G Jernigan, JG Barraud, C Boer, M Dezalay, JP Olive, JF Hurley, K Levine, A Monnelly, G Martel, F Morgan, E Woosley, SE Cline, T Braga, J Manchanda, R Pizzichini, G Takagishi, K Yamauchi, M TI High Energy Transient Explorer 2 observations of the extremely soft X-ray flash XRF 020903 SO ASTROPHYSICAL JOURNAL LA English DT Article DE gamma rays : bursts; X-rays : bursts; X-rays : individual (GRB 020903) ID GAMMA-RAY; BURSTS; ENERGY; BATSE; PEAK; PERFORMANCE; SPECTRA; CATALOG; MONITOR; MODEL AB We report High Energy Transient Explorer 2 (HETE-2) Wide Field X-Ray Monitor/French Gamma Telescope observations of the X-ray flash XRF 020903. This event was extremely soft: the ratio log (S(X)/S(gamma)) = 0.7, where S(X) and S(gamma) are the fluences in the 2 - 30 and 30 - 400 keV energy bands, is the most extreme value observed so far by HETE-2. In addition, the spectrum has an observed peak energy of E(peak)(obs) < 5.0 keV (99.7% probability upper limit), and no photons were detected above similar to 10 keV. The burst is shorter at higher energies, which is similar to the behavior of long gamma-ray bursts (GRBs). We consider the possibility that the burst lies at very high redshift and that the low value of E(peak)(obs) is due to the cosmological redshift, and show that this is very unlikely. We find that the properties of XRF 020903 are consistent with the relation between the fluences S( 7 - 30 keV) and S(30 - 400 keV), found by Barraud et al. for GRBs and X-ray - rich GRBs, and are consistent with the extension by a decade of the hardness-intensity correlation found by the same authors. Assuming that XRF 020903 lies at a redshift z = 0.25, as implied by the host galaxy of the candidate optical and radio afterglows of this burst, we find that the properties of XRF 020903 are consistent with an extension by a factor similar to300 of the relation between the isotropic-equivalent energy E(iso) and the E(peak) of the nuF(nu) spectrum (in the source frame of the burst) found by Amati et al. for GRBs. The results presented in this paper therefore provide evidence that X-ray flashes (XRFs), X-ray-rich GRBs, and GRBs form a continuum and are a single phenomenon. The results also impose strong constraints on models of XRFs and X-ray - rich GRBs. C1 Tokyo Inst Technol, Dept Phys, Meguro Ku, Tokyo 1528551, Japan. Inst Phys & Chem Res, Wako, Saitama 3510198, Japan. Los Alamos Natl Lab, Los Alamos, NM 87545 USA. Univ Chicago, Dept Astron & Astrophys, Chicago, IL 60637 USA. MIT, Ctr Space Res, Cambridge, MA 02139 USA. Observ Midi Pyrenees, Astrophys Lab, F-31400 Toulouse, France. Aoyama Gakuin Univ, Dept Phys, Setagaya Ku, Tokyo 1578572, Japan. Natl Astron Observ, Tokyo 1818588, Japan. Natl Space Dev Agcy Japan, Tsukuba Space Ctr, Tsukuba, Ibaraki 3058505, Japan. New Mexico State Univ, Dept Astron, Las Cruces, NM 88003 USA. Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. UPS, CNRS, Ctr Etud Spatiale Rayonnements, F-31028 Toulouse 4, France. Univ Calif Santa Cruz, Dept Astron & Astrophys, Santa Cruz, CA 95064 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Inst Nacl Pesquisas Espaciais, BR-12227010 Sao Jose Dos Campos, Brazil. Tata Inst Fundamental Res, Dept Astron & Astrophys, Bombay 400005, Maharashtra, India. CNR, IASF, Sez Bologna, I-40129 Bologna, Italy. Miyazaki Univ, Fac Engn, Miyazaki 8892192, Japan. RP Sakamoto, T (reprint author), Tokyo Inst Technol, Dept Phys, Meguro Ku, 2-12-1 Ookayama, Tokyo 1528551, Japan. OI Boer, Michel/0000-0001-9157-4349 NR 40 TC 96 Z9 98 U1 0 U2 3 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 FEB 20 PY 2004 VL 602 IS 2 BP 875 EP 885 DI 10.1086/381232 PN 1 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 779ZK UT WOS:000189343700026 ER PT J AU Alexakis, A Calder, AC Heger, A Brown, EF Dursi, LJ Truran, JW Rosner, R Lamb, DQ Timmes, FX Fryxell, B Zingale, M Ricker, PM Olson, K AF Alexakis, A Calder, AC Heger, A Brown, EF Dursi, LJ Truran, JW Rosner, R Lamb, DQ Timmes, FX Fryxell, B Zingale, M Ricker, PM Olson, K TI On heavy element enrichment in classical novae SO ASTROPHYSICAL JOURNAL LA English DT Article DE hydrodynamics; methods : numerical; novae, cataclysmic variables; nuclear reactions, nucleosynthesis, abundances; waves ID HYDROGEN SHELL FLASHES; ACCRETING WHITE-DWARFS; CNO ABUNDANCES; MASSIVE STARS; NUCLEAR; MODELS; NUCLEOSYNTHESIS; SIMULATIONS; DIFFUSION; EVOLUTION AB Many classical nova ejecta are enriched in CNO and Ne. Rosner and coworkers recently suggested that the enrichment might originate in the resonant interaction between large-scale shear flows in the accreted H/He envelope and gravity waves at the interface between the envelope and the underlying C/O white dwarf (WD). The shear flow amplifies the waves, which eventually form cusps and break. This wave breaking injects a spray of C/O into the superincumbent H/He. Using two-dimensional simulations, we formulate a quantitative expression for the amount of C/O per unit area that can be entrained, at saturation, into the H/He. The fraction of the envelope that is enriched depends on the horizontal distribution of shear velocity and the density contrast between the C/O WD and the H/He layer but is roughly independent of the vertical shape of the shear profile. Using this parameterization for the mixed mass, we then perform several one-dimensional Lagrangian calculations of an accreting WD envelope and consider two scenarios: that the wave breaking and mixing is driven by the convective flows and that the mixing occurs prior to the onset of convection. In the absence of enrichment prior to ignition, the base of the convective zone, as calculated from mixing-length theory with the Ledoux instability criterion, does not reach the C/O interface. As a result, there is no additional mixing, and the runaway is slow. In contrast, the formation of a mixed layer during the accretion of H/He, prior to ignition, causes a more violent runaway. The envelope can be enriched by less than or similar to25% of C/O by mass ( consistent with that observed in some ejecta) for shear velocities, over the surface, with Mach numbers less than or similar to0.4. C1 Univ Chicago, Ctr Astrophys Thermonucl Flashes, Chicago, IL 60637 USA. Univ Chicago, Dept Phys, Chicago, IL 60637 USA. Univ Chicago, Dept Astron & Astrophys, Chicago, IL 60637 USA. Univ Chicago, Enrico Fermi Inst, Chicago, IL 60637 USA. Los Alamos Natl Lab, Theoret Astrophys Grp, Los Alamos, NM 87545 USA. Univ Calif Santa Cruz, Dept Astron & Astrophys, Santa Cruz, CA 95064 USA. Univ Illinois, Dept Astron, Urbana, IL 61801 USA. Univ Illinois, Natl Ctr Supercomp Applicat, Urbana, IL 61801 USA. NASA, UMBC GEST Ctr, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Univ Chicago, Ctr Astrophys Thermonucl Flashes, Chicago, IL 60637 USA. EM alexakis@flash.uchicago.edu RI Brown, Edward/F-1721-2011; Calder, Alan/E-5348-2011; Alexakis, Alexandros/O-8302-2015; OI Alexakis, Alexandros/0000-0003-2021-7728; Brown, Edward/0000-0003-3806-5339; Zingale, Michael/0000-0001-8401-030X; Dursi, Jonathan/0000-0002-4697-798X NR 28 TC 44 Z9 44 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 FEB 20 PY 2004 VL 602 IS 2 BP 931 EP 937 DI 10.1086/381086 PN 1 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 779ZK UT WOS:000189343700032 ER PT J AU Contreras, CS Sahai, R AF Contreras, CS Sahai, R TI Physical structure of the protoplanetary nebula CRL 618. II. Interferometric mapping of millimeter-wavelength HCN J=1-0, HCO+ J=1-0, and continuum emission 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 PROTO-PLANETARY NEBULAE; HIGH-RESOLUTION OBSERVATIONS; MOLECULAR OUTFLOW; BIPOLAR OUTFLOW; EVOLVED STARS; MASS-LOSS; CRL 618; CIRCUMSTELLAR ENVELOPES; RADIO-CONTINUUM; 1.3 MM AB We present interferometric maps with high angular resolution, 1."1 to 1."9, of the HCO+ J = 1-0 and HCN J = 1-0 emission lines in the protoplanetary nebula CRL 618. These molecules are present in both the slowly (similar to10 - 20 km s(-1)) and rapidly (similar to200 km s(-1)) outflowing components of the molecular envelope of CRL 618. The high-velocity (HV) molecular outflow is composed of two compact (mean size similar to1") clumps aligned with the optical lobes and separated by 2."1. The distance between these clumps is now 0."5 larger than 11 yr ago, which is consistent with rapid expansion of the HV clumps. The expansion velocity in the HV outflow increases linearly with the distance to the nebular center, from which we derive a kinematical age of similar to 60 yr. Our data reveal that part of the low-velocity (LV) molecular gas in CRL 618 arises in a extended structure elongated similar to11" in the direction perpendicular to the outflow, which is consistent with a dense, equatorial torus expanding at V-exp similar to 17.5 km s(-1). We have used a two-dimensional spatio-kinematical model to better constrain the structure, kinematics, and density distribution of the HV and LV components that are probed by HCN J = 1-0 and HCO+ J = 1 - 0 emission. The central H II region of CRL 618, which is traced by free-free mm-continuum emission, is unresolved in these observations. We report ( 1) a recent decrease of the mm-continuum flux and ( 2) a 3 mm - to - 1 mm flux ratio consistent with optically thin free-free emission in the millimeter wavelength range. The continuum flux at 3 mm (1 mm) was 1.6 +/- 0.15 Jy (1.2 +/- 0.3 Jy) in 2000, when our observations were performed. The weakening of the millimeter continuum, as well as the decrease of the free-free turnover frequency, could result from a recent cessation of the post-AGB wind or the growth of the cavity of the central H II region ( or both). From a consideration of multiwavelength datasets on CRL 618, we provide a comprehensive view of the temporal evolution of its nebular material. C1 CALTECH, Dept Astron, Pasadena, CA 91125 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Contreras, CS (reprint author), CALTECH, Dept Astron, MS 105-24,1200 E Calif Blvd, Pasadena, CA 91125 USA. EM sanchez@astro.caltech.edu; sahai@eclipse.jpl.nasa.gov RI Sanchez-Contreras, Carmen/N-3718-2015 OI Sanchez-Contreras, Carmen/0000-0002-6341-592X NR 48 TC 21 Z9 21 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 FEB 20 PY 2004 VL 602 IS 2 BP 960 EP 977 PN 1 PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 779ZK UT WOS:000189343700035 ER PT J AU Chen, CH Kamp, I AF Chen, CH Kamp, I TI Are giant planets forming around HR 4796A? SO ASTROPHYSICAL JOURNAL LA English DT Article DE circumstellar matter; planetary systems : formation; stars : individual (HR 4796A) ID CIRCUMSTELLAR DISK; MOLECULAR-HYDROGEN; BETA-PICTORIS; PROTOPLANETARY DISKS; YOUNG STARS; GAS CONTENT; DUST; EMISSION; SEARCH; DEBRIS AB We have obtained Far Ultraviolet Spectroscopic Explorer and Hubble Space Telescope STIS spectra of HR 4796A, a nearby 8 Myr old main-sequence star that possesses a dusty circumstellar disk whose inclination has been constrained from high-resolution near-infrared observations to be similar to17degrees from edge-on. We searched for circumstellar absorption in the ground states of C II lambda1036.3, O t lambda1039.2, Zn II lambda2026.1, Lyman series H(2), and CO (A-X) and failed to detect any of these species. We place upper limits on the column densities and infer upper limits on the gas masses assuming that the gas is in hydrostatic equilibrium, is well mixed, and has a temperature T(gas) similar to 65 K. Our measurements suggest that this system possesses very little molecular gas. Therefore, we infer an upper limit for the gas-to-dust ratio (less than or equal to4.0) assuming that the gas is atomic. We measure less gas in this system than is required to form the envelope of Jupiter. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Leiden Observ, NL-2300 RA Leiden, Netherlands. RP Chen, CH (reprint author), CALTECH, Jet Prop Lab, M-S 169-506,4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM christine.chen@jpl.nasa.gov; kamp@strw.leidenuniv.nl NR 37 TC 28 Z9 28 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 FEB 20 PY 2004 VL 602 IS 2 BP 985 EP 992 DI 10.1086/381243 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 779ZK UT WOS:000189343700037 ER PT J AU Sterling, AC Moore, RL AF Sterling, AC Moore, RL TI Evidence for gradual external reconnection before explosive eruption of a solar filament SO ASTROPHYSICAL JOURNAL LA English DT Article DE Sun : corona; Sun : flares; Sun : UV radiation ID CORONAL MASS EJECTIONS; X-RAY; ACTIVE-REGION; EIT CRINKLES; MODEL; FLARES; ONSET; SOHO; MULTIWAVELENGTH; TELESCOPE AB We observe a slowly evolving quiet-region solar eruption of 1999 April 18, using extreme-ultraviolet (EUV) images from the EUV Imaging Telescope (EIT) on the Solar and Heliospheric Observatory (SOHO) and soft X-ray images from the Soft X-ray Telescope (SXT) on Yohkoh. Using difference images, in which an early image is subtracted from later images, we examine dimmings and brightenings in the region for evidence of the eruption mechanism. A filament rose slowly at about 1 km s(-1) for 6 hours before being rapidly ejected at about 16 km s(-1), leaving flare brightenings and postflare loops in its wake. Magnetograms from the Michelson Doppler Imager (MDI) on SOHO show that the eruption occurred in a large quadrupolar magnetic region with the filament located on the neutral line of the quadrupole's central inner lobe between the inner two of the four polarity domains. In step with the slow rise, subtle EIT dimmings commence and gradually increase over the two polarity domains on one side of the filament, i.e., in some of the loops of one of the two sidelobes of the quadrupole. Concurrently, soft X-ray brightenings gradually increase in both sidelobes. Both of these effects suggest heating in the sidelobe magnetic arcades, which gradually increase over several hours before the fast eruption. Also, during the slow preeruption phase, SXT dimmings gradually increase in the feet and legs of the central lobe, indicating expansion of the central-lobe magnetic arcade enveloping the filament. During the rapid ejection, these dimmings rapidly grow in darkness and in area, especially in the ends of the sigmoid field that erupts with the filament, and flare brightenings begin underneath the fast-moving but still low-altitude filament. We consider two models for explaining the eruption: "breakout,'' which says that reconnection occurs high above the filament prior to eruption, and "tether cutting,'' which says that the eruption is unleashed by reconnection beneath the filament. The pre-eruption evolution is consistent with gradual breakout that led to ( and perhaps caused) the fast eruption. Tether-cutting reconnection below the filament begins early in the rapid ejection, but our data are not complete enough to determine whether this reconnection began early enough to be the cause of the fast-phase onset. Thus, our observations are consistent with gradual breakout reconnection causing the long slow rise of the filament, but allow the cause of the sudden onset of the explosive fast phase to be either a jump in the breakout reconnection rate or the onset of runaway tether-cutting reconnection, or both. C1 NASA, George C Marshall Space Flight Ctr, Space Sci Dept SD50, Huntsville, AL 35812 USA. RP Sterling, AC (reprint author), Inst Space & Astronaut Sci, Yoshinodai 3-1-1, Kanagawa 2298510, Japan. EM asterling@solar.stanford.edu; ron.moore@nasa.gov NR 39 TC 59 Z9 59 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD FEB 20 PY 2004 VL 602 IS 2 BP 1024 EP 1036 DI 10.1086/379763 PN 1 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 779ZK UT WOS:000189343700042 ER PT J AU Abbas, MM LeClair, A Owen, T Conrath, BJ Flasar, FM Kunde, VG Nixon, CA Achterberg, RK Bjoraker, G Jennings, DJ Orton, G Romani, PN AF Abbas, MM LeClair, A Owen, T Conrath, BJ Flasar, FM Kunde, VG Nixon, CA Achterberg, RK Bjoraker, G Jennings, DJ Orton, G Romani, PN TI The nitrogen isotopic ratio in Jupiter's atmosphere from observations by the Composite Infrared Spectrometer on the Cassini spacecraft SO ASTROPHYSICAL JOURNAL LA English DT Article DE ISM : abundances; ISM : evolution; planets and satellites : individual (Jupiter); solar system : formation ID INDUCED ABSORPTION; THERMAL EMISSION; SOLAR-SYSTEM; NUCLEOSYNTHESIS; EVOLUTION; PLANETS; N-15 AB The Composite Infrared Spectrometer (CIRS) on the Cassini spacecraft made infrared observations of Jupiter's atmosphere during the flyby of 2000 December to 2001 January. The unique database in the 600-1400 cm(-1) region with 0.53 and 2.8 cm(-1) spectral resolutions obtained from the observations permits retrieval of global maps of the thermal structure and composition of Jupiter's atmosphere, including the distributions of (NH3)-N-14 and (NH3)-N-15. Analysis of Jupiter's ammonia distributions from three isolated (NH3)-N-15 spectral lines in eight latitudes is presented for evaluation of the nitrogen isotopic ratio. The nitrogen isotopic ratio N-14/N-15 (or N-15/N-14) in Jupiter's atmosphere in this analysis is calculated to be 448 +/- 62 [or (2.23 +/- 0.31) x 10(-3)]. This value of the ratio determined from CIRS data is found to be in very close agreement with the value previously obtained from the measurements by the Galileo Probe Mass Spectrometer. Some possible mechanisms to account for the variation of Jupiter's observed isotopic ratio relative to those of various astrophysical environments are discussed. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. Univ Alabama, Huntsville, AL 35899 USA. Univ Hawaii, Inst Astron, Honolulu, HI 96822 USA. Cornell Univ, Dept Astron, Ithaca, NY 14853 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Maryland, College Pk, MD 20742 USA. Sci Syst & Applicat Inc, Lanham, MD 20706 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Abbas, MM (reprint author), NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. EM mian.m.abbas@nasa.gov; andre.leclair@msfc.nasa.gov; owen@ifa.hawaii.edu; barney.j.conrath@gsfc.nasa.gov; mike@leprss.gsfc.nasa.gov; virgil.g.kunde@gsfc.nasa.gov; conor.a.nixon.1@gsfc.nasa.gov; richard.achterberg@gsfc.nasa.gov; gordon.1.bjoraker@gsfc.nasa.gov; donald.e.jennings.1@gsfc.nasa.gov; glenn.s.orton@jpl.nasa.gov; paul.romani@gsfc.nasa.gov RI Nixon, Conor/A-8531-2009; Flasar, F Michael/C-8509-2012; Romani, Paul/D-2729-2012; Bjoraker, Gordon/D-5032-2012 OI Nixon, Conor/0000-0001-9540-9121; NR 38 TC 30 Z9 30 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 FEB 20 PY 2004 VL 602 IS 2 BP 1063 EP 1074 DI 10.1086/381084 PN 1 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 779ZK UT WOS:000189343700045 ER PT J AU Smith, SJ Cadez, I Chutjian, A Niimura, M AF Smith, SJ Cadez, I Chutjian, A Niimura, M TI Measurement of the metastable lifetime for the 2s(2)2p(2) (1)S(0) level in O(2+) SO ASTROPHYSICAL JOURNAL LA English DT Article DE atomic data; atomic processes ID C-I SEQUENCE; FORBIDDEN TRANSITIONS; IONS; CONFIGURATION; CARBON; RATES AB The radiative lifetime of the 2s(2)2p(2) (1)S(0) level in O(2+) has been measured via the magnetic-dipole (M1) transition 2s(2)2p(2) (1)S(0) --> (3)P(1) at 232.17 nm. Data were recorded in a Kingdon trap, with the source of ions a 14 GHz electron cyclotron resonance ion source. The lifetime of the (1)S(0) level was found to be 540 +/- 27 ms. This is in good agreement with a previous measurement and with a number of theoretical calculations. Metastable lifetimes, when combined with collisional excitation rates, can provide a diagnostic for electron density Ne in a stellar or solar plasma. C1 CALTECH, Jet Prop Lab, Atom & Mol Collis Grp, Pasadena, CA 91109 USA. Jozef Stefan Inst, Ljubljana 1000, Slovenia. RP Smith, SJ (reprint author), CALTECH, Jet Prop Lab, Atom & Mol Collis Grp, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 22 TC 8 Z9 8 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 FEB 20 PY 2004 VL 602 IS 2 BP 1075 EP 1078 DI 10.1086/381120 PN 1 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 779ZK UT WOS:000189343700046 ER PT J AU Ballantyne, DR Strohmayer, TE AF Ballantyne, DR Strohmayer, TE TI The evolution of the accretion disk around 4U 1820-30 during a superburst SO ASTROPHYSICAL JOURNAL LA English DT Article DE accretion, accretion disks; line : formation; stars : individual (4U 1820-30); stars : neutron; X-rays : binaries; X-rays : bursts ID X-RAY REFLECTION; ACTIVE GALACTIC NUCLEI; GLOBULAR-CLUSTERS; NEUTRON-STARS; BLACK-HOLES; COLD MATTER; BURSTS; RADIATION; SPECTRA; BINARIES AB Accretion from a disk onto a collapsed, relativistic star - a neutron star or black hole - is the mechanism widely believed to be responsible for the emission from compact X- ray binaries. Because of the extreme spatial resolution required, it is not yet possible to directly observe the evolution or dynamics of the inner parts of the accretion disk where general relativistic effects are dominant. Here we use the bright X- ray emission from a superburst on the surface of the neutron star 4U 1820 - 30 as a spotlight to illuminate the disk surface. The X- rays cause iron atoms in the disk to fluoresce, allowing a determination of the ionization state, covering factor and inner radius of the disk over the course of the burst. The time- resolved spectral fitting shows that the inner region of the disk is disrupted by the burst, possibly being heated into a thicker, more tenuous flow, before recovering its previous form in similar to 1000 s. This marks the first instance that the evolution of the inner regions of an accretion disk has been observed in real time. C1 Canadian Inst Theoret Astrophys, Toronto, ON M5S 3H8, Canada. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Ballantyne, DR (reprint author), Canadian Inst Theoret Astrophys, 60 St George St, Toronto, ON M5S 3H8, Canada. EM ballantyne@cita.utoronto.ca; stroh@clarence.gsfc.nasa.gov NR 34 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 FEB 20 PY 2004 VL 602 IS 2 BP L105 EP L108 DI 10.1086/382703 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 779ZL UT WOS:000189343800009 ER PT J AU Creech-Eakman, MJ Orton, GS Serabyn, E Hayward, TL AF Creech-Eakman, MJ Orton, GS Serabyn, E Hayward, TL TI Mid-infrared detection of the L dwarf DENISP J0255-4700 SO ASTROPHYSICAL JOURNAL LA English DT Article DE infrared : stars; stars : atmospheres; stars : individual (DENISP J0255.0-4700); stars : low-mass, brown dwarfs ID INFRARED-TELESCOPE-FACILITY; EXTRASOLAR GIANT PLANETS; DIGITAL SKY SURVEY; BROWN DWARFS; T-DWARFS; GLIESE 229B; CLASSIFICATION; PHOTOMETRY; SPECTRUM; MODELS AB We have observed DENISP J0255.0 - 4700 in four mid- infrared photometric passbands at the Gemini South observatory using OSCIR. The photometry indicates that a temperature less than or equal to 1400 K fits the data reasonably well. This temperature is consistent with previously derived values using optical and near- infrared data and also with our evolutionary parameter estimates of log (L/L.) = -4.62 at a distance of 5 pc and an age of 2 - 4 Gyr. The implied mass is 60M(J) - 70M(J). While it is somewhat problematic to fit existing models to the mid- infrared spectrum of DENISP J0255.0 - 4700, the 10 and 11 mum photometric data appear to be impacted by NH3 absorption. A full spectrum and better models of dwarfs at the L- to T- type transition are required to confirm this. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Assoc Univ Res Astron Inc, Gemini Observ, La Serena, Chile. RP Creech-Eakman, MJ (reprint author), New Mexico Inst Min & Technol, Dept Phys, 801 Leroy Pl, Socorro, NM 87801 USA. EM mce@s383.jpl.nasa.gov NR 31 TC 6 Z9 6 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD FEB 20 PY 2004 VL 602 IS 2 BP L129 EP L132 DI 10.1086/382589 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 779ZL UT WOS:000189343800015 ER PT J AU Jenet, FA Gil, J AF Jenet, FA Gil, J TI The intrinsic intensity modulation of PSR B1937+21 at 1410 MHz SO ASTROPHYSICAL JOURNAL LA English DT Article DE pulsars : general; pulsars : individual (PSR B1937+21) ID PULSAR RADIO-EMISSION; MILLISECOND PULSAR; RADIATION; B1937+21; MODEL; GAPS AB The single- pulse properties of the millisecond radio pulsar PSR B1937 + 21 are studied at 1410 MHz. The nongiant pulse emission regions appear to be remarkably stable, showing no pulse- to- pulse fluctuations other then those induced by the interstellar medium. This type of behavior has not been seen in any other pulsar, although it was seen in previous 430 MHz observations of this source. The stability of this source is interpreted in the context of the sparking gap model of radio pulsar emission, and a model- dependent upper bound is placed on the Lorentz factor of the outflowing plasma. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Zielona Gora, Inst Astron, PL-65265 Zielona Gora, Poland. RP Jenet, FA (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 26 TC 8 Z9 8 U1 0 U2 0 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD FEB 20 PY 2004 VL 602 IS 2 BP L89 EP L92 DI 10.1086/382212 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 779ZL UT WOS:000189343800005 ER PT J AU Gillespie, TW Brock, J Wright, CW AF Gillespie, TW Brock, J Wright, CW TI Prospects for quantifying structure, floristic composition and species richness of tropical forests SO INTERNATIONAL JOURNAL OF REMOTE SENSING LA English DT Article ID SPATIAL-RESOLUTION IMAGERY; RAIN-FOREST; BASAL AREA; STAND CHARACTERISTICS; AIRBORNE LIDAR; CANOPY; FRAGMENTS; BIOMASS; CLASSIFICATION; TREES AB Airborne spectral and light detection and ranging (lidar) sensors have been used to quantify biophysical characteristics of tropical forests. Lidar sensors have provided high-resolution data on forest height, canopy topography, volume, and gap size; and provided estimates on number of strata in a forest, successional status of forests, and above-ground biomass. Spectral sensors have provided data on vegetation types, foliar biochemistry content of forest canopies, tree and canopy phenology, and spectral signatures for selected tree species. A number of advances are theoretically possible with individual and combined spectral and lidar sensors for the study of forest structure, floristic composition and species richness. Delineating individual canopies of over-storey trees with small footprint lidar and discrimination of tree architectural types with waveform distributions is possible and would provide scientists with a new method to study tropical forest structure. Combined spectral and lidar data can be used to identify selected tree species and identify the successional status of tropical forest fragments in order to rank forest patches by levels of species richness. It should be possible in the near future to quantify selected patterns of tropical forests at a higher resolution than can currently be undertaken in the field or from space. C1 Univ Calif Los Angeles, Dept Geog, Los Angeles, CA 90095 USA. US Geol Survey, St Petersburg, FL 33701 USA. NASA, Goddard Space Flight Ctr, Wallops Flight Facil, Wallops Isl, VA 23337 USA. RP Gillespie, TW (reprint author), Univ Calif Los Angeles, Dept Geog, Los Angeles, CA 90095 USA. NR 47 TC 31 Z9 34 U1 0 U2 10 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 FEB 20 PY 2004 VL 25 IS 4 BP 707 EP 715 DI 10.1080/01431160310001598917 PG 9 WC Remote Sensing; Imaging Science & Photographic Technology SC Remote Sensing; Imaging Science & Photographic Technology GA 760QC UT WOS:000187844400003 ER PT J AU Guild, LS Cohen, WB Kauffman, JB AF Guild, LS Cohen, WB Kauffman, JB TI Detection of deforestation and land conversion in Rondonia, Brazil using change detection techniques SO INTERNATIONAL JOURNAL OF REMOTE SENSING LA English DT Article ID THEMATIC MAPPER DATA; NUTRIENT POOLS; AMAZON; FOREST; IMAGERY; BIOMASS; FIRE; DYNAMICS; TRANSFORMATION; EMISSIONS AB Fires associated with tropical deforestation, land conversion and land use greatly contribute to emissions as well as the depletion of carbon and nutrient pools. The objective of this research was to compare change detection techniques for identifying deforestation and cattle pasture formation during a period of early colonization and agricultural expansion in the vicinity of Jamari, Rondonia. Multi-date Landsat Thematic Mapper (TM) data between 1984 and 1992 were examined in a 94370 ha area of active deforestation to map land cover change. The tasselled cap (TC) transformation was used to enhance the contrast between forest, cleared areas and regrowth. TC images were stacked into a composite multi-date TC and used in a principal components (PC) transformation to identify change components. In addition, consecutive TC image pairs were differenced and stacked into a composite multi-date differenced image. A maximum likelihood classification of each image composite was compared for identification of land cover change. The multi-date TC composite classification had the best accuracy of 0.78 (kappa). By 1984, only 5% of the study area had been cleared, but by 1992, 11% of the area had been deforested, primarily for pasture, and 7% lost due to hydroelectric dam flooding. Finally, discrimination of pasture versus cultivation was improved due to the ability to detect land under sustained clearing opposed to land exhibiting regrowth with infrequent clearing. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Oregon State Univ, Dept Forest Sci, Corvallis, OR 97331 USA. Oregon State Univ, Dept Fisheries & Wildlife, Corvallis, OR 97331 USA. RP Guild, LS (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. NR 39 TC 38 Z9 40 U1 4 U2 16 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 FEB 20 PY 2004 VL 25 IS 4 BP 731 EP 750 DI 10.1080/01431160310001598935 PG 20 WC Remote Sensing; Imaging Science & Photographic Technology SC Remote Sensing; Imaging Science & Photographic Technology GA 760QC UT WOS:000187844400005 ER PT J AU Morgan, CG Allen, M Liang, MC Shia, RL Blake, GA Yung, YL AF Morgan, CG Allen, M Liang, MC Shia, RL Blake, GA Yung, YL TI Isotopic fractionation of nitrous oxide in the stratosphere: Comparison between model and observations SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE isotope; N2O; stratosphere ID ATMOSPHERIC N2O; ULTRAVIOLET-ABSORPTION; MIDDLE ATMOSPHERE; UV PHOTOLYSIS; TRACE GASES; EXCITED O-2; TRANSPORT; OZONE; ADVECTION; SIMULATIONS AB [1] We investigate the mass dependent isotopic fractionation mechanisms, based on photolytic destruction and reaction with O(D-1), to explain the N-15/N-14 and O-18/O-16 fractionation of stratospheric N2O and reconcile laboratory experiments with atmospheric observations. The Caltech/JPL two-dimensional (2-D) model is utilized for detailed studies of N2O and its isotopologues and isotopomers in the stratosphere. We compare model results with observations of isotopic enrichment using three different methods of calculating photolytic cross-sections for each of the major isotopologues and isotopomers of N2O. Although the Yung and Miller [1997] successfully modeled the pattern of enrichments for each isotopologue or isotopomer relative to each other, their approach underestimated the magnitude of the enrichments. The ab initio approach by Johnson et al. [ 2001] provides a better fit to the magnitudes of the enrichments, with the notable exception of the enrichment for the (NNO)-N-15-N-14-O-16. A simpler, semi-empirical approach by Blake et al. [2003] is able to model the magnitude of all the enrichments, including the one for (NNO)-N-15-N-14-O-16. The Blake et al. [2003] cross-sections are temperature-dependent, but adjustments are needed to match the measurements of Kaiser et al. [2002a]. Using these modified cross-sections generally improves the agreement between model and mass spectrometric measurements. Destruction of N2O by reaction with O(D-1) results in a small but nonnegligible isotopic fractionation in the lower stratosphere. On a per molecule basis, the rates of destruction of the minor isotopologues or isotopomers are somewhat less than that for (NNO)-N-14-N-14-O-16. From our 2-D model we infer the relative rates for isotopologues and isotopomers (NNO)-N-14-N-14-O-16 (446), (NNO)-N-14-N-15-O-16 (456), N-15 N-14 O-16 (546), (NN)-N-14-N-14 O-17 (447) and (NNO)-N-14-N-14-O-18 (448), to be 1, 0.9843, 0.9942, 0.9949, and 0.9900, respectively. Thus the destruction of N2O in the atmosphere results in isotopic fractionations of (456), (546), (447) and (448) by 19.4, 9.5, 5.5 and 12.0parts per thousand. If we do not distinguish between the (456) and ( 546) isotopomers, the mean isotopic fractionation for N-15 is 14.5%. If we assume that the mean tropospheric values for delta(456), delta(546), delta(15)N and delta(18)O are 16.35, - 2.35, 7.0 and 20.7parts per thousand, respectively, we infer the following isotopic signature for the integrated sources of N2O: delta(456) = - 2.9parts per thousand, delta(546) = - 11.7parts per thousand, delta(15)N = - 7.3parts per thousand and delta(18)O = 8.7parts per thousand. C1 CALTECH, Jet Prop Lab, Div Earth & Space Sci, Pasadena, CA 91109 USA. CALTECH, Dept Geol & Planetary Sci, Pasadena, CA 91125 USA. RP Morgan, CG (reprint author), SRI Int, Mol Phys Lab, 333 Ravenswood Ave, Menlo Pk, CA 94025 USA. EM yly@gps.caltech.edu NR 80 TC 36 Z9 36 U1 3 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 FEB 20 PY 2004 VL 109 IS D4 AR D04305 DI 10.1029/2003JD003402 PG 22 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 780HF UT WOS:000189373700001 ER PT J AU Pizzarello, S Weber, AL AF Pizzarello, S Weber, AL TI Prebiotic amino acids as asymmetric catalysts SO SCIENCE LA English DT Article ID NUCLEIC-ACID; ORIGIN C1 Arizona State Univ, Dept Chem & Biochem, Tempe, AZ 85287 USA. NASA, Ames Res Ctr, SETI Inst, Moffett Field, CA 94035 USA. RP Pizzarello, S (reprint author), Arizona State Univ, Dept Chem & Biochem, Tempe, AZ 85287 USA. NR 7 TC 212 Z9 215 U1 3 U2 42 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 FEB 20 PY 2004 VL 303 IS 5661 BP 1151 EP 1151 DI 10.1126/science.1093057 PG 1 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 775RP UT WOS:000189074700034 PM 14976304 ER PT J AU Canzian, A Mosca, HO Bozzolo, G AF Canzian, A Mosca, HO Bozzolo, G TI Surface alloying of Pd on Cu(111) SO SURFACE SCIENCE LA English DT Article DE adatoms; computer simulations; copper; palladium; semi-empirical models and model calculations; alloys; surface structure, morphology, roughness, and topography ID EQUIVALENT-CRYSTAL THEORY; MULTILAYER RELAXATION; CU; GROWTH; FE; AL AB A modeling analysis of the growth mode of submonolayer amounts of Pd on Cu(111) for different coverages and temperatures reproduces the known experimental behavior, including the formation of a surface alloy, the presence of subsurface Pd, formation of Pd bands off terrace steps, and weak short range surface ordering. An atom-by-atom analysis of the energetics using the BFS method for alloys provides a simple explanation of the underlying mechanisms leading to the observed behavior. (C) 2004 Elsevier B.V. All rights reserved. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. Ohio Aerosp Inst, Cleveland, OH 44142 USA. UAM, Comis Nacl Energia Atom, RA-1650 San Martin, Buenos Aires, Argentina. Univ Tecnol Nacl, Fac Reg Gral Pacheco, RA-1617 Gral Pacheco, Buenos Aires, Argentina. RP Bozzolo, G (reprint author), NASA, Glenn Res Ctr, Mail Stop 23-2,21000 Brookpk Rd, Cleveland, OH 44135 USA. EM guillermo.h.bozzolo@grc.nasa.gov NR 15 TC 13 Z9 13 U1 0 U2 5 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD FEB 20 PY 2004 VL 551 IS 1-2 BP 9 EP 22 DI 10.1016/j.susc.2003.12.004 PG 14 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA 778GJ UT WOS:000189230900004 ER PT J AU Larsson, MI AF Larsson, MI TI Deposition rate dependence of nanopatterning on periodically strained surfaces SO SURFACE SCIENCE LA English DT Article DE Monte Carlo simulations; self-assembly; surface stress; surface diffusion; nucleation; surface structure; morphology, roughness. and topography; single crystal epitaxy; silver ID QUANTUM-DOT SUPERLATTICES; SELF-ORGANIZATION; CRYSTAL-SURFACES; GROWTH; NANOSTRUCTURES; DISLOCATIONS; DIFFUSION; LAYER AB The deposition rate dependence of nanopattern formation on periodically strained surfaces is investigated by means of kinetic Monte Carlo simulations. This study proposes that technologically achievable strain fields (that often are less than 1%) can be used to produce periodic nanopatterns of reasonable quality for a narrow range of deposition rates. On the other hand. for large strain-field modulations good nanopatterning can be achieved for a wide range of deposition rates. We show that the optimum nanopattern quality does not only depend on surface strain field, temperature and deposition rate but also on the amount of material deposited. The best nanopatterns are obtained after the deposition of material corresponding to 30% of a full surface layer. (C) 2004 Elsevier B.V. All rights reserved. C1 Stanford Univ, Dept Mat Sci & Engn, Stanford, CA 94305 USA. RP Larsson, MI (reprint author), NASA, Nanostellar Inc, Res Pk, Moffett Field, CA 94035 USA. EM mats@nanostellar.com NR 16 TC 4 Z9 4 U1 0 U2 0 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0039-6028 J9 SURF SCI JI Surf. Sci. PD FEB 20 PY 2004 VL 551 IS 1-2 BP 69 EP 79 DI 10.1016/j.susc.2003.12.047 PG 11 WC Chemistry, Physical; Physics, Condensed Matter SC Chemistry; Physics GA 778GJ UT WOS:000189230900009 ER PT J AU Langlais, B Purucker, ME Mandea, M AF Langlais, B Purucker, ME Mandea, M TI Crustal magnetic field of Mars SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article DE Mars; magnetic field; magnetic anomalies; equivalent sources; magnetization ID SPHERICAL HARMONIC MODEL; GLOBAL SURVEYOR MISSION; REMANENT MAGNETIZATION; IMPACT CRATERS; HIGH-ALTITUDE; HEMATITE; EARTH; DEMAGNETIZATION; PYRRHOTITE; INVERSION AB [1] The equivalent source dipole technique is used to model the three components of the Martian lithospheric magnetic field. We use magnetic field measurements made on board the Mars Global Surveyor spacecraft. Different input dipole meshes are presented and evaluated. Because there is no global, Earth-like, inducing magnetic field, the magnetization directions are solved for together with the magnetization intensity. A first class of models is computed using either low-altitude or high-altitude measurements, giving some statistical information about the depth of the dipoles. Then, a second class of models is derived on the basis of measurements made between 80 and 430 km altitude. The 4840 dipoles are placed 20 km below the surface, with a mean spacing of 2.92degrees (173 km). Residual rms values between observations and predictions are as low as 15 nT for the total field, with associated correlation coefficient equal to 0.97. The resulting model is used to predict the magnetic field at 200-km constant altitude. We present the maps of the magnetic field and of the magnetization. Downward continuation of a spherical harmonic model derived from our equivalent source solution suggests that intermediate-scale lithospheric fields at the surface probably exceed 5000 nT. Given an assumed 40-km-thick magnetized layer, with a mean volume per dipole equal to 3.6.10(6) km(3), the magnetization components range between +/-12 A/m. We also present apparent correlations between some impact craters (greater than or equal to300-km diameter) and magnetization contrasts. Finally, we discuss the implications of the directional information and possible magnetic carriers. C1 NASA, Goddard Space Flight Ctr, Geodynam Branch, NAS,NRC, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Geodynam Branch, Raytheon ITSS, Greenbelt, MD 20771 USA. Inst Phys Globe, F-75252 Paris 05, France. RP NASA, Goddard Space Flight Ctr, Geodynam Branch, NAS,NRC, Greenbelt, MD 20771 USA. EM langlais@ltpmail.gsfc.nasa.gov; purucker@ltpmail.gsfc.nasa.gov; mioara@ipgp.jussieu.fr RI MANDEA, Mioara/E-4892-2012; Langlais, Benoit/K-5366-2012 OI Langlais, Benoit/0000-0001-5207-304X NR 57 TC 101 Z9 102 U1 1 U2 6 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 FEB 19 PY 2004 VL 109 IS E2 AR E02008 DI 10.1029/2003JE002048 PG 16 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 780HM UT WOS:000189374400001 ER PT J AU Hickson, KM Keyser, LF AF Hickson, KM Keyser, LF TI Kinetics of the Cl(P-2(J)) + C2H6 reaction between 177 and 353 K SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID CL ATOM REACTIONS; COMPETITIVE CHLORINATION REACTIONS; RATE CONSTANTS; GAS-PHASE; DIODE-LASER; HALOCARBON MEASUREMENTS; ABSTRACTION REACTION; RATE COEFFICIENTS; SIMPLE ALKANES; ETHANE AB Absolute rate data for the Cl + C2H6 --> HCl + C2H5 reaction have been measured from 177 to 353 K using a conventional discharge flow resonance fluorescence technique with helium as the diluent at a pressure of 1 Torr. The rate coefficient at 296 K was measured to be (5.70 +/- 0.13) x 10(-11) cm(3) molecule(-1) s(-1). The Arrhenius expression which describes the temperature dependence of the rate coefficient is (7.32 +/- 0.39) x 10(-11) exp[(-73.6 +/- 12.9)/7] cm(3) molecule(-1) s(-1). The cited errors are at the level of two standard deviations. The results were checked for potential interferences from nonequilibration of atomic Cl spin states, impurities in the Cl atom source, and other secondary chemistry resulting from high reactant concentrations. There was no observed change in the rate coefficient upon the addition of a large concentration of efficient spin quencher, CF4. The results were also found to be invariant to purification of the Cl atom precursor. Numerical simulations confirmed that at the low reactant concentrations used, secondary reactions did not affect the observed rate coefficients to a significant extent. C1 CALTECH, Jet Prop Lab, Earth & Space Sci Div, Atmospher Chem Element, Pasadena, CA 91109 USA. RP Keyser, LF (reprint author), CALTECH, Jet Prop Lab, Earth & Space Sci Div, Atmospher Chem Element, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM Leon.F.Keyser@jpl.nasa.gov RI Hickson, Kevin/A-2443-2012 OI Hickson, Kevin/0000-0001-8317-2606 NR 49 TC 8 Z9 8 U1 0 U2 2 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1089-5639 J9 J PHYS CHEM A JI J. Phys. Chem. A PD FEB 19 PY 2004 VL 108 IS 7 BP 1150 EP 1159 DI 10.1021/jp036458f PG 10 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 774AM UT WOS:000188957600007 ER PT J AU Wang, CM Hajj, G Pi, XQ Rosen, IG Wilson, B AF Wang, CM Hajj, G Pi, XQ Rosen, IG Wilson, B TI Development of the Global Assimilative Ionospheric Model SO RADIO SCIENCE LA English DT Article DE Global Assimilative Ionospheric Model (GAIM); ionospheric data assimilation; GPS-TEC data analysis; adjoint method; band-limited Kalman filter; ionospheric forecast AB [1] This paper provides an overview of the development of the Global Assimilative Ionospheric Model (GAIM) by a team of investigators from the University of Southern California (USC) and the Jet Propulsion Laboratory (JPL). The USC/JPL GAIM utilizes data assimilation techniques, which are widely used in meteorological applications, for the purpose of monitoring and forecasting Earth's ionosphere. We discuss the general structure of GAIM, which includes a first-principles model of the ionosphere, a series of auxiliary models for the driving forces, a data processing subsystem, and an optimization subsystem. Two techniques for the estimation of electron density and driving forces in the ionosphere are presented: The four-dimensional variational method and the Kalman filter. Some validation methods and results are also presented. These results demonstrate the potential of GAIM in providing accurate specification of the ionosphere. C1 Univ So Calif, Dept Math, Los Angeles, CA 90089 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Wang, CM (reprint author), Univ So Calif, Dept Math, 1042 W 36th Pl,Denney Res Bldg 346, Los Angeles, CA 90089 USA. EM cwang@math.usc.edu NR 11 TC 63 Z9 64 U1 0 U2 9 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 FEB 19 PY 2004 VL 39 IS 1 AR RS1S06 DI 10.1029/2002RS002854 PG 11 WC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications SC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications GA 780HV UT WOS:000189375200003 ER PT J AU Lundgren, P Casu, F Manzo, M Pepe, A Berardino, P Sansosti, E Lanari, R AF Lundgren, P Casu, F Manzo, M Pepe, A Berardino, P Sansosti, E Lanari, R TI Gravity and magma induced spreading of Mount Etna volcano revealed by satellite radar interferometry SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID SAR INTERFEROMETRY; DEFORMATION; FLANK; GPS AB Mount Etna underwent a cycle of eruptive activity over the past ten years. Here we compute ground displacement maps and deformation time series from more than 400 radar interferograms to reveal Mount Etna's average and time varying surface deformation from 1992 to 2001. We find that during this time interval it experienced magmatic inflation and radial spreading to the West, South, and East. Steady relative motion between the West and South flanks, and between the East and North flanks, during this time interval, suggests they are related to gravitational spreading of the volcanic edifice. Time series analysis shows that growth of a southeastern basal anticline began with the end of magma recharge in 1995, thus showing a direct link between deep-seated magma intrusions and edifice spreading. These observations support a complex mode of radial gravitational collapse underlain by deeper magma driven basal spreading, although ultimately the two must be related. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. CNR, IREA, I-80124 Naples, Italy. RP Lundgren, P (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM paul@weed.jpl.nasa.gov; casu.f@irea.cnr.it; manzo.mr@irea.cnr.it; pepe.a@irea.cnr.it; berardino.p@irea.cnr.it; sansosti.e@irea.cnr.it; lanari.r@irea.cnr.it RI Sansosti, Eugenio/F-7297-2011; Casu, Francesco/H-3793-2011; Pepe, Antonio/J-9454-2016; OI Sansosti, Eugenio/0000-0002-5051-4056; Pepe, Antonio/0000-0002-7843-3565; Casu, Francesco/0000-0001-8555-6494 NR 18 TC 85 Z9 87 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 FEB 17 PY 2004 VL 31 IS 4 AR L04602 DI 10.1029/2003GL018736 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 780GW UT WOS:000189372800002 ER PT J AU West, WC Whitacre, JF Lim, JR AF West, WC Whitacre, JF Lim, JR TI Chemical stability enhancement of lithium conducting solid electrolyte plates using sputtered LiPON thin films SO JOURNAL OF POWER SOURCES LA English DT Article DE LiPON; CPE AB Sputter deposition of LiPON films directly onto high Li+ conductivity solid electrolyte plates has been investigated as a means to minimize the reactivity of the plates to metallic Li. The LiPON films were shown to effectively passivate the plates in contact with metallic Li, in contrast to unpassivated plates that reacted immediately in contact with Li metal. The conductivity of the passivated solid electrolyte plates was measured to be 1.0 x 10(-4) S cm(-1), with Arrhenius activation energy of 0.36 eV and an electrochemical stability window of at least 0-5.0 V versus Li/Li+. The passivated solid electrolyte was capable of supporting electrochemical plating and stripping of Li metal, as demonstrated by EIS and CV measurements. These high chemical stability, high Li+ conductivity solid electrolyte plates will be useful for solid-state batteries employing Li anodes. (C) 2003 Elsevier B.V. All rights reserved. C1 CALTECH, Jet Prop Lab, Electrochem Technol Grp, Pasadena, CA 91109 USA. RP West, WC (reprint author), CALTECH, Jet Prop Lab, Electrochem Technol Grp, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM william.c.west@jpl.nasa.gov NR 7 TC 52 Z9 56 U1 12 U2 69 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0378-7753 J9 J POWER SOURCES JI J. Power Sources PD FEB 16 PY 2004 VL 126 IS 1-2 BP 134 EP 138 DI 10.1016/j.jpowsour.2003.08.030 PG 5 WC Chemistry, Physical; Electrochemistry; Energy & Fuels; Materials Science, Multidisciplinary SC Chemistry; Electrochemistry; Energy & Fuels; Materials Science GA 773WG UT WOS:000188947000018 ER PT J AU West, WC Myung, NV Whitacre, JF Ratnakumar, BV AF West, WC Myung, NV Whitacre, JF Ratnakumar, BV TI Electrodeposited amorphous manganese oxide nanowire arrays for high energy and power density electrodes SO JOURNAL OF POWER SOURCES LA English DT Article DE amorphous manganese oxide; power density electrode; nanowire ID HIGH-CAPACITY; INSERTION; DIOXIDE AB Arrays of manganese oxide nanowires were electrodeposited into anodized alumina membranes. These nanowire arrays were investigated in terms of their structural and electrochemical properties as cathodes for high energy and high power density Li ion batteries. The nanowire arrays were assembled with a Li counter electrode and non-aqueous electrolyte to form secondary batteries. These cells were capable of multiple charge/discharge cycles, with a cathode specific capacity of approximately 300 mAh/g. Though the cathodes were fabricated without any binder or conductive additives, the electrodes could be discharged at current densities up to 0.1 mA/cm(2) before the onset of any significant polarization. (C) 2003 Elsevier B.V. All rights reserved. C1 CALTECH, Jet Prop Lab, Electrochem Technol Grp, Pasadena, CA 91109 USA. CALTECH, Jet Prop Lab, MEMS Technol Grp, Pasadena, CA 91109 USA. RP West, WC (reprint author), CALTECH, Jet Prop Lab, Electrochem Technol Grp, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM william.c.west@jpl.nasa.gov NR 9 TC 44 Z9 46 U1 3 U2 23 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0378-7753 J9 J POWER SOURCES JI J. Power Sources PD FEB 16 PY 2004 VL 126 IS 1-2 BP 203 EP 206 DI 10.1016/j.jpowsour.2003.08.020 PG 4 WC Chemistry, Physical; Electrochemistry; Energy & Fuels; Materials Science, Multidisciplinary SC Chemistry; Electrochemistry; Energy & Fuels; Materials Science GA 773WG UT WOS:000188947000030 ER PT J AU Hinkov, I Grand, J de la Chapelle, ML Farhat, S Scott, CD Nikolaev, P Pichot, V Launois, P Mevellec, JY Lefrant, S AF Hinkov, I Grand, J de la Chapelle, ML Farhat, S Scott, CD Nikolaev, P Pichot, V Launois, P Mevellec, JY Lefrant, S TI Effect of temperature on carbon nanotube diameter and bundle arrangement: Microscopic and macroscopic analysis SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID ELECTRIC-ARC TECHNIQUE; SINGLE-WALL NANOTUBES; VIBRATIONAL-MODES; RAMAN-SCATTERING; LASER-ABLATION; GROWTH; PRESSURE AB The diameter distribution of the nanotubes produced by electric-arc discharge are measured using Raman spectroscopy at various wavelengths. These measurements agree with the results provided by two other techniques: high-resolution transmission electron microscopy and x-ray diffraction. The mean tube diameter shifts more than 0.1 nm with the increase of argon in the inert atmosphere. Some argon concentrations favored the synthesis of metallic tubes with specific diameters. Furthermore, the background gas influences the macroscopic characteristics of nanotube yield and bundle size, as determined by Brunauer-Emmett-Teller surface area measurements and x-ray diffraction. The information collected on nanotube diameter and arrangement is correlated with temperatures calculated using a numerical model of the plasma generated between the two electrodes. Indeed, plasma temperature control during the production process is achieved using argon-helium mixtures as buffer gases. The variation of the gas mixture from pure argon to pure helium changes the plasma temperature and hence the nanotube diameter. (C) 2004 American Institute of Physics. C1 Univ Paris 13, LIMHP, F-93430 Villetaneuse, France. Univ Technol Troyes, LNIO, F-10010 Troyes, France. NASA, Lyndon B Johnson Space Ctr ES4, Houston, TX 77058 USA. GB Tech NASA Johnson Space Ctr, Houston, TX 77258 USA. Univ Paris 11, Phys Solides Lab, CNRS, UMR 8502, F-91405 Orsay, France. Univ Nantes, Inst Mat Nantes, LPC, F-44322 Nantes, France. RP Farhat, S (reprint author), Univ Paris 13, LIMHP, Ave JB Clement, F-93430 Villetaneuse, France. EM farhat@limhp.univ-paris13.fr RI Nikolaev, Pavel/B-9960-2009 NR 35 TC 19 Z9 19 U1 0 U2 4 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD FEB 15 PY 2004 VL 95 IS 4 BP 2029 EP 2037 DI 10.1063/1.1638620 PG 9 WC Physics, Applied SC Physics GA 769MP UT WOS:000188654100065 ER PT J AU Davis, AB Marshak, A AF Davis, AB Marshak, A TI Photon propagation in heterogeneous optical media with spatial correlations: enhanced mean-free-paths and wider-than-exponential free-path distributions SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Article DE Beer's law; photon propagation; mean-free-path; three-dimensional radiative transfer; spatially correlated heterogeneous media; cloudy atmospheres ID LIQUID WATER DISTRIBUTIONS; SMALL-SCALE STRUCTURE; MARINE STRATOCUMULUS; CLOUDS; RADIATION; EXTINCTION; INTERMITTENCY; INVARIANCE; CENTIMETER; ISSUES AB Beer's law of exponential decay in direct transmission is well-known but its break-down in spatially variable optical media has been discussed only sporadically in the literature. We document here this break-down in three-dimensional (3D) media with complete generality and explore its ramifications for photon propagation. We show that effective transmission laws and their associated free-path distributions (FPDs) are in fact never exactly exponential in variable media of any kind. Moreover, if spatial correlations in the extinction field extend at least to the scale of the mean-free-path (MFP), FPDs are necessarily wider-than-exponential in the sense that all higher-order moments of the relevant mean-field FPDs exceed those of the exponential FPD, even if it is tuned to yield the proper MFP. The MFP itself is always larger than the inverse of average extinction in a variable medium. In a vast and important class of spatially-correlated random media, the MFP is indeed the average of the inverse of extinction. We translate these theoretical findings into a practical method for deciding a priori when 3D effects become important. Finally, we discuss an obvious but limited analogy between our analysis of spatial variability and the well-known effects of strong spectral variability in gaseous media when observed or modeled at moderate resolution. (C) 2003 Elsevier Ltd. All rights reserved. C1 Los Alamos Natl Lab, Space & Remote Sensing Sci Grp, Los Alamos, NM 87545 USA. NASA, Goddard Space Flight Ctr, Climate & Radiat Branch, Greenbelt, MD 20771 USA. RP Davis, AB (reprint author), Los Alamos Natl Lab, Space & Remote Sensing Sci Grp, POB 1663,NIS-2, Los Alamos, NM 87545 USA. EM adavis@lanl.gov RI Marshak, Alexander/D-5671-2012 NR 35 TC 42 Z9 42 U1 0 U2 4 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 FEB 15 PY 2004 VL 84 IS 1 BP 3 EP 34 DI 10.1016/S0022-4073(03)00114-6 PG 32 WC Optics; Spectroscopy SC Optics; Spectroscopy GA 764HX UT WOS:000188202400001 ER PT J AU Stow, DA Hope, A McGuire, D Verbyla, D Gamon, J Huemmrich, F Houston, S Racine, C Sturm, M Tape, K Hinzman, L Yoshikawa, K Tweedie, C Noyle, B Silapaswan, C Douglas, D Griffith, B Jia, G Epstein, H Walker, D Daeschner, S Petersen, A Zhou, LM Myneni, R AF Stow, DA Hope, A McGuire, D Verbyla, D Gamon, J Huemmrich, F Houston, S Racine, C Sturm, M Tape, K Hinzman, L Yoshikawa, K Tweedie, C Noyle, B Silapaswan, C Douglas, D Griffith, B Jia, G Epstein, H Walker, D Daeschner, S Petersen, A Zhou, LM Myneni, R TI Remote sensing of vegetation and land-cover change in Arctic Tundra Ecosystems SO REMOTE SENSING OF ENVIRONMENT LA English DT Review DE Arctic tundra vegetation; vegetation change; land cover change; global climate; Alaska ID LEAF-AREA INDEX; NEAR-INFRARED CHANNELS; NET PRIMARY PRODUCTION; AVHRR DATA; GROWING-SEASON; CO2 FLUX; SURFACE-TEMPERATURE; NORTHERN ALASKA; ATMOSPHERIC CO2; HIGH-LATITUDES AB The objective of this paper is to review research conducted over the past decade on the application of multi-temporal remote sensing for monitoring changes of Arctic tundra lands. Emphasis is placed on results from the National Science Foundation Land-Air-Ice Interactions (LAII) program and on optical remote sensing techniques. Case studies demonstrate that ground-level sensors on stationary or moving track platforms and wide-swath imaging sensors on polar orbiting satellites are particularly useful for capturing optical remote sensing data at sufficient frequency to study tundra vegetation dynamics and changes for the cloud prone Arctic. Less frequent imaging with high spatial resolution instruments on aircraft and lower orbiting satellites enable more detailed analyses of land cover change and calibration/validation of coarser resolution observations. The strongest signals of ecosystem change detected thus far appear to correspond to expansion of tundra shrubs and changes in the amount and extent of thaw lakes and ponds. Changes in shrub cover and extent have been documented by modem repeat imaging that matches archived historical aerial photography. NOAA Advanced Very High Resolution Radiometer (AVHRR) time series provide a 20-year record for determining changes in greenness that relates to photosynthetic activity, net primary production, and growing season length. The strong contrast between land materials and surface waters enables changes in lake and pond extent to be readily measured and monitored. (C) 2003 Elsevier Inc. All rights reserved. C1 San Diego State Univ, Dept Geog, San Diego, CA 92182 USA. Univ Alaska, US Geol Survey, Alaska Cooperat Fish & Wildlife Res Unit, Fairbanks, AK 99775 USA. Univ Alaska, Dept Forest Sci, Fairbanks, AK 99775 USA. Calif State Univ Los Angeles, Ctr Environm Anal, Los Angeles, CA 90032 USA. Calif State Univ Los Angeles, Dept Biol Sci, Los Angeles, CA 90032 USA. Univ Maryland Baltimore Cty, NASA, Goddard Space Flight Ctr, Joint Ctr Earth Syst Technol, Greenbelt, MD 20771 USA. USA, Cold Reg Res & Engn Lab, Hanover, NH 03755 USA. USA, CRREL, Ft Wainwright, AK USA. Univ Alaska, Inst Geophys, Fairbanks, AK 99775 USA. Univ Alaska Fairbanks, Inst No Engn, Water & Environm Res Ctr, Fairbanks, AK 99775 USA. Michigan State Univ, Dept Plant Biol, Arct Ecol Lab, E Lansing, MI 48824 USA. Space Imaging Solut, Michigan Off, Ann Arbor, MI 48108 USA. Univ Alaska, Dept Biol & Wildlife, Fairbanks, AK 99775 USA. USGS Alaska, Ctr Biol Sci, Glacier Bay Field Stn, Juneau Off, Douglas, AK 99824 USA. Univ Alaska, USGS Alaska Cooperat Fish & Wildlife Res Unit, Fairbanks, AK 99775 USA. Univ Virginia, Dept Environm Sci, Charlottesville, VA 22904 USA. Univ Alaska, Inst Arctic Biol, Fairbanks, AK 99775 USA. Georgia Inst Technol, Sch Earth & Atmospher Sci, Atlanta, GA 30332 USA. Boston Univ, Dept Geog, Boston, MA 02215 USA. RP Stow, DA (reprint author), San Diego State Univ, Dept Geog, San Diego, CA 92182 USA. EM stow@mail.sdsu.edu RI Zhou, Liming/A-2688-2012; Gamon, John/A-2641-2014; Myneni, Ranga/F-5129-2012 OI Gamon, John/0000-0002-8269-7723; NR 106 TC 290 Z9 346 U1 23 U2 200 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 FEB 15 PY 2004 VL 89 IS 3 BP 281 EP 308 DI 10.1016/j.rse.2003.10.018 PG 28 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA 768TA UT WOS:000188590100003 ER PT J AU Salomonson, VV Appel, I AF Salomonson, VV Appel, I TI Estimating fractional snow cover from MODIS using the normalized difference snow index SO REMOTE SENSING OF ENVIRONMENT LA English DT Article DE MODIS; fractional snow cover; remote sensing; FOS terra; EOS aqua ID RESOLUTION IMAGING SPECTRORADIOMETER; GENERAL-CIRCULATION MODELS; SIMULATION; ALBEDO; VARIABILITY; PRODUCTS; SYSTEM; EXTENT; MASS AB Snow-cover information is important for a wide variety of scientific studies, water supply and management applications. The NASA Earth Observing System (EOS) Moderate Resolution Imaging Spectroradiometer (MODIS) provides improved capabilities to observe snow cover from space and has been successfully using a normalized difference snow index (NDSI), along with threshold tests, to provide global, automated binary maps of snow cover. The NDSI is a spectral band ratio that takes advantage of the spectral differences of snow in short-wave infrared and visible MODIS spectral bands to identify snow versus other features in a scene. This study has evaluated whether there is a "signal" in the NDSI that could be used to estimate the fraction of snow within a 500 in MODIS pixel and thereby enhance the use of the NDSI approach in monitoring snow cover. Using Landsat 30-m observations as "ground truth," the percentage of snow cover was calculated for 500-m cells. Then a regression relationship between 500-m NDSI observations and fractional snow cover was developed over three different snow-covered regions and tested over other areas. The overall results indicate that the relationship between fractional snow cover and NDSI is reasonably robust when applied locally and over large areas like North America. The relationship offers advantages relative to other published fractional snow cover algorithms developed for global-scale use with MODIS. This study indicates that the fraction of snow cover within a MODIS pixel using this approach can be provided with a mean absolute error less than 0.1 over the range from 0.0 to 1.0 in fractional snow cover. (C) 2003 Elsevier Inc. All rights reserved. C1 NASA, Goddard Space Flight Ctr, Earth Sci Directorate, Greenbelt, MD 20771 USA. Raytheon ITSS, Upper Marlboro, MD 20774 USA. RP Salomonson, VV (reprint author), NASA, Goddard Space Flight Ctr, Earth Sci Directorate, Mail Code 974, Greenbelt, MD 20771 USA. EM Vincent.V.salomonson@nasa.gov RI Appel, Igor/E-7940-2011 OI Appel, Igor/0000-0003-0907-3807 NR 37 TC 236 Z9 268 U1 5 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 FEB 15 PY 2004 VL 89 IS 3 BP 351 EP 360 DI 10.1016/j.rse.2003.10.016 PG 10 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA 768TA UT WOS:000188590100006 ER PT J AU Deeter, MN Emmons, LK Francis, GL Edwards, DP Gille, JC Warner, JX Khattatov, B Ziskin, D Lamarque, JF Ho, SP Yudin, V Attie, JL Packman, D Chen, J Mao, D Drummond, JR Novelli, P Sachse, G AF Deeter, MN Emmons, LK Francis, GL Edwards, DP Gille, JC Warner, JX Khattatov, B Ziskin, D Lamarque, JF Ho, SP Yudin, V Attie, JL Packman, D Chen, J Mao, D Drummond, JR Novelli, P Sachse, G TI Evaluation of operational radiances for the Measurements of Pollution in the Troposphere (MOPITT) instrument CO thermal band channels SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE MOPITT; validation; radiative transfer model ID CARBON-MONOXIDE; MIXING RATIOS; MODEL; RETRIEVAL AB The ability of operational radiative transfer models to accurately predict remote sensing instrument observations (e.g., calibrated radiances) over a wide variety of geophysical situations is critical to the performance of trace gas retrieval algorithms. As part of the validation of the Measurements of Pollution in the Troposphere (MOPITT) satellite instrument, we present a technique for comparing operational calibrated thermal band (4.7 mum) Earth-view MOPITT radiances with corresponding values calculated using the MOPITT operational radiative transfer model. In situ carbon monoxide (CO) profiles sampled from aircraft in coordination with MOPITT overpasses serve as the foundation for MOPITT validation. Characteristics of radiance errors due to in situ sampling characteristics, CO temporal and spatial variability, and surface emissivity are discussed. Results indicate that radiance biases for most of the MOPITT thermal channel radiances are typically on the order of 1%. Observed radiance biases are largest and most variable for the pressure modulation cell difference-signal radiances, probably because of the lack of in situ data in the upper troposphere and lower stratosphere. C1 Natl Ctr Atmospher Res, Div Atmospher Chem, Boulder, CO 80307 USA. Observ Midi Pyrenees, Lab Aerol, F-31400 Toulouse, France. Univ Toronto, Dept Phys, Toronto, ON M5S 1A7, Canada. NOAA, Climate Monitoring & Diagnost Lab, Boulder, CO 80303 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Deeter, MN (reprint author), Natl Ctr Atmospher Res, Div Atmospher Chem, POB 3000, Boulder, CO 80307 USA. EM mnd@ucar.edu; emmons@ucar.edu; gfrancis@ucar.edu; edwards@ucar.edu; gille@ucar.edu; juying@ucar.edu; boris@ucar.edu; ziskin@ucar.edu; lamar@ucar.edu; spho@ucar.edu; vyudin@ucar.edu; attjl@aero.obs-mip.fr; pack@ucar.edu; jschen@ucar.edu; dmao@ucar.edu; jim@atmosp.physics.utoronto.ca; pnovelli@cmdl.noaa.gov; g.w.sachse@larc.nasa.gov RI Lamarque, Jean-Francois/L-2313-2014; Drummond, James/O-7467-2014; Deeter, Merritt/O-6078-2016; Emmons, Louisa/R-8922-2016 OI Lamarque, Jean-Francois/0000-0002-4225-5074; Deeter, Merritt/0000-0002-3555-0518; Emmons, Louisa/0000-0003-2325-6212 NR 18 TC 24 Z9 24 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 FEB 14 PY 2004 VL 109 IS D3 AR D03308 DI 10.1029/2003JD003970 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 775QK UT WOS:000189052800004 ER PT J AU Emmons, LK Deeter, MN Gille, JC Edwards, DP Attie, JL Warner, J Ziskin, D Francis, G Khattatov, B Yudin, V Lamarque, JF Ho, SP Mao, D Chen, JS Drummond, J Novelli, P Sachse, G Coffey, MT Hannigan, JW Gerbig, C Kawakami, S Kondo, Y Takegawa, N Schlager, H Baehr, J Ziereis, H AF Emmons, LK Deeter, MN Gille, JC Edwards, DP Attie, JL Warner, J Ziskin, D Francis, G Khattatov, B Yudin, V Lamarque, JF Ho, SP Mao, D Chen, JS Drummond, J Novelli, P Sachse, G Coffey, MT Hannigan, JW Gerbig, C Kawakami, S Kondo, Y Takegawa, N Schlager, H Baehr, J Ziereis, H TI Validation of Measurements of Pollution in the Troposphere (MOPITT) CO retrievals with aircraft in situ profiles SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE carbon monoxide; MOPITT; validation ID CARBON-MONOXIDE; FAST-RESPONSE; INSTRUMENT; FLUORESCENCE AB Validation of the Measurements of Pollution in the Troposphere (MOPITT) retrievals of carbon monoxide (CO) has been performed with a varied set of correlative data. These include in situ observations from a regular program of aircraft observations at five sites ranging from the Arctic to the tropical South Pacific Ocean. Additional in situ profiles are available from several short-term research campaigns situated over North and South America, Africa, and the North and South Pacific Oceans. These correlative measurements are a crucial component of the validation of the retrieved CO profiles and columns from MOPITT. The current validation results indicate good quantitative agreement between MOPITT and in situ profiles, with an average bias less than 20 ppbv at all levels. Comparisons with measurements that were timed to sample profiles coincident with MOPITT overpasses show much less variability in the biases than those made by various groups as part of research field experiments. The validation results vary somewhat with location, as well as a change in the bias between the Phase 1 and Phase 2 retrievals ( before and after a change in the instrument configuration due to a cooler failure). During Phase 1, a positive bias is found in the lower troposphere at cleaner locations, such as over the Pacific Ocean, with smaller biases at continental sites. However, the Phase 2 CO retrievals show a negative bias at the Pacific Ocean sites. These validation comparisons provide critical assessments of the retrievals and will be used, in conjunction with ongoing improvements to the retrieval algorithms, to further reduce the retrieval biases in future data versions. C1 Natl Ctr Atmospher Res, Div Atmospher Chem, Boulder, CO 80307 USA. Observ Midi Pyrenees, Lab Aerol, F-31400 Toulouse, France. Univ Toronto, Dept Phys, Toronto, ON M5S 1A7, Canada. Natl Ctr Atmospher Res, Climate Monitoring & Diagnost Lab, Div Atmospher Chem, Boulder, CO 80307 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. Harvard Univ, Dept Earth & Planetary Sci, Cambridge, MA 02138 USA. Japan Aerosp Explorat Agcy, Off Space Applicat, Tsukuba, Ibaraki 3058505, Japan. Univ Tokyo, Adv Sci & Technol Res Ctr, Meguro Ku, Tokyo 1538904, Japan. DLR, Inst Atmospher Phys, D-82234 Wessling, Germany. RP Natl Ctr Atmospher Res, Div Atmospher Chem, POB 3000, Boulder, CO 80307 USA. EM emmons@ucar.edu; mnd@ucar.edu; gille@ucar.edu; edwards@ucar.edu; attjl@aero.obs-mip.fr; jamesw@ucar.edu; ziskin@ucar.edu; gfrancis@ucar.edu; boris@ucar.edu; vyudin@ucar.edu; lamar@ucar.edu; spho@ucar.edu; dmao@ucar.edu; jschen@ucar.edu; james.drummond@utoronto.ca; pnovelli@cmdl.noaa.gov; g.w.sachse@larc.nasa.gov; coffey@ucar.edu; jamesw@ucar.edu; chg@io.harvard.edu; kawakami.shuji@jaxa.jp; kondo@atmos.rcast.u-tokyo.ac.jp; takegawa@atmos.rcast.u-tokyo.ac.jp; hans.schlager@dlr.de; janine.baehr@dlr.de; ziereis@dlr.de RI Kondo, Yutaka/D-1459-2012; Gerbig, Christoph/L-3532-2013; Lamarque, Jean-Francois/L-2313-2014; Drummond, James/O-7467-2014; Deeter, Merritt/O-6078-2016; Emmons, Louisa/R-8922-2016 OI Gerbig, Christoph/0000-0002-1112-8603; Lamarque, Jean-Francois/0000-0002-4225-5074; Deeter, Merritt/0000-0002-3555-0518; Emmons, Louisa/0000-0003-2325-6212 NR 21 TC 140 Z9 141 U1 1 U2 20 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD FEB 14 PY 2004 VL 109 IS D3 AR D03309 DI 10.1029/2003JD004101 PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 775QK UT WOS:000189052800005 ER PT J AU Stossel, A Markus, T AF Stossel, A Markus, T TI Using satellite-derived ice concentration to represent Antarctic coastal polynyas in ocean climate models SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article DE coastal polynyas; ocean climate models ID TERRA-NOVA BAY; SEA-ICE; WEDDELL SEA; SOUTHERN-OCEAN; BOTTOM WATER; INTERANNUAL VARIABILITY; MEAN CIRCULATION; BOUNDARY-LAYER; CONVECTION; SENSITIVITY AB [1] The focus of this paper is on the representation of Antarctic coastal polynyas in global ice-ocean general circulation models (OGCMs), in particular their local, regional, and high-frequency behavior. This is verified with the aid of daily ice concentration derived from satellite passive microwave data using the "NASA Team 2'' (NT2) and the bootstrap (BS) algorithms. Large systematic regional and temporal discrepancies arise, some of which are related to the type of convection parameterization used in the model. An attempt is made to improve the fresh-water flux associated with melting and freezing in Antarctic coastal polynyas by ingesting ( assimilating) satellite ice concentration where it comes to determining the thermodynamics of the open-water fraction of a model grid cell. Since the NT2 coastal open-water fraction ( polynyas) tends to be less extensive than the simulated one in the decisive season and region, assimilating NT2 coastal ice concentration yields overall reduced net freezing rates, smaller formation rates of Antarctic Bottom Water, and a stronger southward flow of North Atlantic Deep Water across 30 degreesS. Enhanced net freezing rates occur regionally when NT2 coastal ice concentration is assimilated, concomitant with a more realistic ice thickness distribution and accumulation of High-Salinity Shelf Water. Assimilating BS rather than NT2 coastal ice concentration, the differences to the non-assimilated simulation are generally smaller and of opposite sign. This suggests that the model reproduces coastal ice concentration in closer agreement with the BS data than with the NT2 data, while more realistic features emerge when NT2 data are assimilated. C1 Texas A&M Univ, Dept Oceanog, College Stn, TX 77843 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Stossel, A (reprint author), Texas A&M Univ, Dept Oceanog, 3146 TAMU, College Stn, TX 77843 USA. EM astoessel@ocean.tamu.edu; thorsten.markus@nasa.gov RI Markus, Thorsten/D-5365-2012 NR 55 TC 6 Z9 6 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9275 EI 2169-9291 J9 J GEOPHYS RES-OCEANS JI J. Geophys. Res.-Oceans PD FEB 14 PY 2004 VL 109 IS C2 AR C02014 DI 10.1029/2003JC001779 PG 12 WC Oceanography SC Oceanography GA 775QT UT WOS:000189053800002 ER PT J AU Jiang, JH Wang, B Goya, K Hocke, K Eckermann, SD Ma, J Wu, DL Read, WG AF Jiang, JH Wang, B Goya, K Hocke, K Eckermann, SD Ma, J Wu, DL Read, WG TI Geographical distribution and interseasonal variability of tropical deep convection: UARS MLS observations and analyses SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE convective processes; gravity waves; stratosphere-troposphere interaction; tropical meteorology ID STRATOSPHERIC WATER-VAPOR; GRAVITY-WAVE ACTIVITY; EQUATORIAL ATMOSPHERE DYNAMICS; UPPER-TROPOSPHERIC HUMIDITY; LIMB SOUNDER OBSERVATIONS; ANNUAL CYCLE; DIURNAL CYCLE; TROPOPAUSE TEMPERATURES; RADIOSONDE OBSERVATIONS; GLOBAL PRECIPITATION AB [1] Tropical deep convection and its dynamical effect on the tropopause and stratosphere are investigated using a suite of data from the Upper Atmospheric Research Satellite (UARS) Microwave Limb Sounder (MLS), including upper tropospheric humidity, cloud radiance, and gravity wave measurements. For this purpose, geographical distributions of temperature, water vapor, and cloudiness in the tropical tropopause layer (TTL) are compared with corresponding maps of gravity wave variance in the stratosphere. In addition, ECMWF global wind divergent and velocity potential fields as well as NOAA outgoing longwave radiation and CMAP rainfall data are analyzed to help pinpoint the locations of deep convection. We found that high-altitude clouds near the bottom of TTL ( similar to 147 hPa) are usually surrounded by high-humidity air, and their spatial pattern and seasonal variability are closely associated with regions of vigorous summertime deep convection. Upward propagating gravity waves generated from these convection regions are shifted poleward by prevailing stratospheric winds. We estimate that tropical deep convection lifts similar to 5% of the cloud tops to altitudes above 100 hPa and that most of the extreme deep convection events occur in the Western Pacific and Indian monsoon regions. Low-temperature regions in the TTL are associated with, but often drift away from, the center of deep convection. Regions of water vapor maxima near the bottom of TTL are located directly above the deep convection centers, but this moisture behavior is somewhat reversed at the top of the TTL. The integrated picture derived from this study implies that convective scale motions could be important in affecting short-term dehydration processes in the TTL. Our results also suggest that the spatial organization and temporal development of tropical convective systems will be better monitored with the follow-on Earth Observing System (EOS) Aura satellite instruments and lead to improved understanding of the complex interaction of tropical convection with large-scale dynamic and thermodynamic conditions. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Hawaii, Dept Meteorol, Honolulu, HI 96822 USA. Kyushu Univ, Geophys Fluid Dynam Lab, Fukuoka 8128581, Japan. Max Planck Inst Aeron, D-37191 Katlenburg Lindau, Germany. USN, Res Lab, Middle Atmosphere Dynam Sect, Washington, DC 20375 USA. Computat Phys Inc, Springfield, VA USA. RP Jiang, JH (reprint author), CALTECH, Jet Prop Lab, Mail Stop 183-701,4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM jonathan@mls.jpl.nasa.gov; wangbin@hawaii.edu; goya@geo.kyushu-u.ac.jp; sigrid.hocke@t-online.de; eckerman@uap2.nrl.navy.mil; junma@uap2.nrl.navy.mil; dwu@mls.jpl.nasa.gov; bill@mls.jpl.nasa.gov RI U-ID, Kyushu/C-5291-2016; Wu, Dong/D-5375-2012 NR 78 TC 84 Z9 86 U1 3 U2 15 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD FEB 13 PY 2004 VL 109 IS D3 AR D03111 DI 10.1029/2003JD003756 PG 19 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 775QG UT WOS:000189052500001 ER PT J AU Yu, HB Dickinson, RE Chin, M Kaufman, YJ Zhou, M Zhou, L Tian, Y Dubovik, O Holben, BN AF Yu, HB Dickinson, RE Chin, M Kaufman, YJ Zhou, M Zhou, L Tian, Y Dubovik, O Holben, BN TI Direct radiative effect of aerosols as determined from a combination of MODIS retrievals and GOCART simulations SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE aerosols; radiative forcing; albedo ID RESOLUTION IMAGING SPECTRORADIOMETER; SKY RADIANCE MEASUREMENTS; SINGLE-SCATTERING ALBEDO; GLOBAL-MODEL GOCART; OPTICAL-PROPERTIES; BLACK CARBON; SAHARAN DUST; TROPOSPHERIC AEROSOL; ANTHROPOGENIC AEROSOLS; ATMOSPHERIC AEROSOLS AB [1] The aerosol direct solar effect under clear sky is assessed by ( 1) combining multiple aerosol characterizations and ( 2) using the satellite-retrieved land surface albedo. The aerosol characterization is made through an integration of the MODerate resolution Imaging Spectroradiometer (MODIS) retrievals and the Georgia Tech/Goddard Global Ozone Chemistry Aerosol Radiation and Transport (GOCART) model simulations. The spectral and bidirectional albedo of land surface is derived from MODIS. On a global average, the solar forcing at the top of atmosphere (TOA) DFTOA is - 4.5 Wm(-2), of which about 1/3 is contributed by a sum of natural and anthropogenic sulfate and carbonaceous aerosols. Though the optical depth is about 50% higher over land than over ocean, no significant land-ocean contrast in this TOA forcing is observed. It is reduced by larger aerosol absorption and higher surface albedo over land. As a result of absorption by soot and dust, a much larger surface cooling and substantial atmospheric absorption coexist over land and adjacent oceans. Globally, the surface cooling DFSFC is about - 9.9 Wm(-2), and the atmospheric absorption DFAIR is about 5.4 Wm(-2), suggesting that more than half of the surface cooling results from the atmospheric absorption. Sensitivity tests show that an inclusion of MODIS-derived anisotropy of land surface reflection reduces the diurnal variation of TOA solar forcing, because of aerosol-induced changes in the fraction of direct beam and hence in the effective reflection from the surface. Constraining the GOCART dust absorption with recent measurements reduces DFAIR and DFSFC by 1.3 Wm(-2) and 0.9 Wm(-2), respectively, and increases the TOA cooling by 0.4 W m(-2). C1 Georgia Inst Technol, Sch Earth & Atmospher Sci, Atlanta, GA 30332 USA. NASA, Goddard Space Flight Ctr, Biospher Sci Branch, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Lab Atmospheres, Greenbelt, MD 20771 USA. RP Georgia Inst Technol, Sch Earth & Atmospher Sci, Atlanta, GA 30332 USA. EM yu@breeze.eas.gatech.edu RI Yu, Hongbin/C-6485-2008; Dubovik, Oleg/A-8235-2009; Chin, Mian/J-8354-2012; Zhou, Liming/A-2688-2012 OI Yu, Hongbin/0000-0003-4706-1575; Dubovik, Oleg/0000-0003-3482-6460; NR 82 TC 72 Z9 76 U1 2 U2 11 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 FEB 12 PY 2004 VL 109 IS D3 AR D03206 DI 10.1029/2003JD003914 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 775QE UT WOS:000189052200003 ER PT J AU Jiang, JH Eckermann, SD Wu, DL Ma, J AF Jiang, JH Eckermann, SD Wu, DL Ma, J TI A search for mountain waves in MLS stratospheric limb radiances from the winter Northern Hemisphere: Data analysis and global mountain wave modeling SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE gravity waves; dynamics; general circulation; global modeling; vortex; jet stream ID ATMOSPHERE RESEARCH SATELLITE; INERTIA-GRAVITY-WAVES; MIDDLE ATMOSPHERE; UARS MLS; TEMPERATURE-FLUCTUATIONS; MESOSCALE VARIABILITY; SOUNDER OBSERVATIONS; GENERAL-CIRCULATION; VARIANCE; PROPAGATION AB Despite evidence from ground-based data that flow over mountains is a dominant source of gravity waves (GWs) for the Northern Hemisphere winter middle atmosphere, GW-related signals in global limb radiances from the Microwave Limb Sounder (MLS) on the Upper Atmosphere Research Satellite (UARS) have shown little direct evidence of mountain waves. We address this issue by combining a renewed analysis of MLS limb-track and limb-scan radiances with global mountain wave modeling using the Naval Research Laboratory Mountain Wave Forecast Model (MWFM). MLS radiance variances show characteristics consistent with mountain waves, such as enhanced variance over specific mountain ranges and annual variations that peak strongly in winter. However, direct comparisons of MLS variance maps with MWFM-simulated mountain wave climatologies reveal limited agreement. We further develop a detailed "MLS GW visibility function'' that accurately specifies the three-dimensional in-orbit sensitivity of the MLS limb-track radiance measurement to a spectrum of GWs with different wavelengths and horizontal propagation directions. On postprocessing MWFM-generated mountain wave fields through these MLS visibility filters, we generate MWFM variance maps that agree substantially better with MLS radiance variances. This combined data analysis and MLS-filtered MWFM modeling leads us to conclude that many MLS variance enhancements can be associated with mountain waves forced by flow over specific mountainous terrain. These include mountain ranges in Europe (e.g., Scandinavia; Alps; Scotland; Ural, Putoran, Altai, Hangay and Sayan Mountains; Yablonovyy, Stanovoy, Khingan, Verkhoyansk and Central Ranges), North America (e.g., Brooks Range, MacKenzie Mountains, Colorado Rockies), southeastern Greenland, and Iceland. Our results show that given careful consideration of the in-orbit sensitivity of the instrument to GWs, middle atmospheric limb radiances measured from UARS MLS, as well as from the new MLS instrument on the Earth Observing System (EOS) satellite, can provide important global information on mountain waves in the extratropical Northern Hemisphere stratosphere and mesosphere. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. USN, Res Lab, Middle Atmosphere Dynam Sect, Washington, DC 20375 USA. Computat Phys Inc, Springfield, VA 22151 USA. RP CALTECH, Jet Prop Lab, M-S 183-701,4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM jonathan.h.jiang@jpl.nasa.gov; stephen.eckermann@nrl.navy.mil; dong.l.wu@jpl.nasa.gov; junma@uap2.nrl.navy.mil RI Wu, Dong/D-5375-2012 NR 62 TC 52 Z9 52 U1 3 U2 7 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X EI 2169-8996 J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD FEB 11 PY 2004 VL 109 IS D3 AR D03107 DI 10.1029/2003JD003974 PG 22 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 775QB UT WOS:000189051900003 ER PT J AU Palosz, B Stel'makh, S Grzanka, E Gierlotka, S Pielaszek, R Bismayer, U Werner, S Palosz, W AF Palosz, B Stel'makh, S Grzanka, E Gierlotka, S Pielaszek, R Bismayer, U Werner, S Palosz, W TI High pressure x-ray diffraction studies on nanocrystalline materials SO JOURNAL OF PHYSICS-CONDENSED MATTER LA English DT Article; Proceedings Paper CT Euroschool on New Materials and their Dynamics - Advances throuth Synchrotron Radiation CY SEP 29-OCT 11, 2002 CL Rostock Warnemunde, GERMANY ID RANGE ATOMIC ORDER; SURFACE STRESS; LATTICE-PARAMETER; CDSE NANOCRYSTALS; SIZE DEPENDENCE; SMALL PARTICLES; NANOSTRUCTURED MATERIALS; STRAIN DISTRIBUTION; POWDER DIFFRACTION; NANOPARTICLES AB dApplication of the in situ high pressure powder diffraction technique for examination of specific structural properties of nanocrystals based on the experimental data of SiC nanocrystalline powders of 2-30 nm in diameter is presented. Limitations and capabilities of the experimental techniques themselves and methods of diffraction data elaboration applied to nanocrystals with very small dimensions (<30 nm) are discussed. It is shown that a unique value of the lattice parameter cannot be determined for such small crystals using a standard powder diffraction experiment. It is also shown that, due to the complex structure constituting a two-phase, core/surface shell system, no unique compressibility coefficient can satisfactorily describe the behaviour of nanocrystalline powders under pressure. We offer a tentative interpretation of the distribution of macro- and micro-strains in nanoparticles of different grain size. C1 UNIPRESS, High Pressure Res Ctr, PL-01142 Warsaw, Poland. Univ Warsaw, Inst Expt Phys, PL-00681 Warsaw, Poland. Univ Hamburg, Mineral Petrog Inst, D-20146 Hamburg, Germany. Univ Munich, Inst Kristallog, D-20146 Munich, Germany. NASA, George C Marshall Space Flight Ctr, Univ Space Res Assoc, Huntsville, AL 35812 USA. RP Palosz, B (reprint author), UNIPRESS, High Pressure Res Ctr, Ul Sokolowska 29-37, PL-01142 Warsaw, Poland. NR 65 TC 38 Z9 40 U1 0 U2 4 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 FEB 11 PY 2004 VL 16 IS 5 SI SI BP S353 EP S377 AR PII S0953-8984(04)70032-6 DI 10.1088/0953-8984/16/5/003 PG 25 WC Physics, Condensed Matter SC Physics GA 800SU UT WOS:000220048800004 ER PT J AU Veselovskii, I Kolgotin, A Griaznov, V Muller, D Franke, K Whiteman, DN AF Veselovskii, I Kolgotin, A Griaznov, V Muller, D Franke, K Whiteman, DN TI Inversion of multiwavelength Raman lidar data for retrieval of bimodal aerosol size distribution SO APPLIED OPTICS LA English DT Article ID MICROPHYSICAL PARTICLE PARAMETERS; EUROPEAN POLLUTION OUTBREAKS; TROPICAL INDIAN-OCEAN; INDO-ASIAN HAZE; BACKSCATTER LIDAR; OPTICAL-PROPERTIES; EXTINCTION; REGULARIZATION; ACE-2; SIMULATION AB We report on the feasibility of deriving microphysical parameters of bimodal particle size distributions from Mie-Raman lidar based on a triple Nd:YAG laser. Such an instrument provides backscatter coefficients at 355, 532, and 1064 nm and extinction coefficients at 355 and 532 nm. The inversion method employed is Tikhonov's inversion with regularization. Special attention has been paid to extend the particle size range for which this inversion scheme works to similar to10 mum, which makes this algorithm applicable to large particles, e.g., investigations concerning the hygroscopic growth of aerosols. Simulations showed that surface area, volume concentration, and effective radius are derived to an accuracy of similar to50% for a variety of bimodal particle size distributions. For particle size distributions with an effective radius of <1 mum the real part of the complex refractive index was retrieved to an accuracy of +/-0.05, the imaginary part was retrieved to 50% uncertainty. Simulations dealing with a mode-dependent complex refractive index showed that an average complex refractive index is derived that lies between the values for the two individual modes. Thus it becomes possible to investigate external mixtures of particle size distributions, which, for example, might be present along continental rims along which anthropogenic pollution mixes with marine aerosols. Measurement cases obtained from the Institute for Tropospheric Research six-wavelength aerosol lidar observations during the Indian Ocean Experiment were used to test the capabilities of the algorithm for experimental data sets. A benchmark test was attempted for the case representing anthropogenic aerosols between a broken cloud deck. A strong contribution of particle volume in the coarse mode of the particle size distribution was found. (C) 2004 Optical Society of America. C1 Gen Phys Inst, Phys Instrumentat Ctr, Troitsk 142190, Moscow Region, Russia. Inst Tropospher Res, D-04318 Leipzig, Germany. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Veselovskii, I (reprint author), Gen Phys Inst, Phys Instrumentat Ctr, Troitsk 142190, Moscow Region, Russia. EM katyv@orc.ru; detlef@tropos.de; franke@tropos.de; david.whiteman@gsfc.nasa.gov RI MUELLER, DETLEF/F-1010-2015 OI MUELLER, DETLEF/0000-0002-0203-7654 NR 35 TC 73 Z9 77 U1 0 U2 10 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 FEB 10 PY 2004 VL 43 IS 5 BP 1180 EP 1195 DI 10.1364/AO.43.001180 PG 16 WC Optics SC Optics GA 773BY UT WOS:000188878900023 PM 15008501 ER PT J AU Kazanas, D Teplitz, VL AF Kazanas, D Teplitz, VL TI Competition between gravitational and scalar field radiation SO ASTROPHYSICAL JOURNAL LA English DT Article DE binaries : general; cosmology : theory; gravitational waves; radiation mechanisms : general ID PROBE WMAP OBSERVATIONS; DIMENSIONS; RELATIVITY; ENERGY AB Recent astrophysical observations have provided strong evidence that the present expansion of the universe is accelerating, powered by the energy density associated with a cosmological term. Assuming the latter to be not simply a constant term but a "quintessence" field, we study the radiation of quanta of such a quintessence field ("quintons") by binary systems of different types and compare intensities to those of standard tensor gravitational wave emission. We consider both the case in which the quintessence field varies only over cosmological distances and the case in which it is modified spatially by (strong) gravitational fields, a condition that results in bounds on the gradient of the scalar field. We show that, in both the first case and, because of a bound we derive from the Hulse-Taylor pulsar, in the second, there is not sufficient quinton radiation to affect expected LISA and LIGO gravity wave signals from binary systems. We show that in the second case, the Large Hadron Collider is capable of setting a bound similar to that from the binary pulsar. C1 NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. So Methodist Univ, Dept Phys, Dallas, TX 75725 USA. RP Kazanas, D (reprint author), NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Code 661, Greenbelt, MD 20771 USA. EM demos.kazanas-1@nasa.gov; vigdor.l.teplitz@nasa.gov NR 14 TC 1 Z9 1 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 FEB 10 PY 2004 VL 602 IS 1 BP 111 EP 115 DI 10.1086/380963 PN 1 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 779MT UT WOS:000189304900010 ER PT J AU Levenson, NA Weaver, KA Heckman, TM Awaki, H Terashima, Y AF Levenson, NA Weaver, KA Heckman, TM Awaki, H Terashima, Y TI Accretion and outflow in the active galactic nucleus and starburst of NGC 5135 SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : individual (NGC 5135); galaxies : Seyfert; galaxies : starburst; X-rays : galaxies ID SEYFERT 2 GALAXIES; X-RAY-EMISSION; CHANDRA OBSERVATIONS; INFRARED GALAXIES; LUMINOSITY; REFLECTION; FEATURES; DISTRIBUTIONS; ULTRAVIOLET; MINISURVEY AB Observations of the Seyfert 2 and starburst galaxy NGC 5135 with the Chandra X-Ray Observatory demonstrate that both of these phenomena contribute significantly to its X-ray emission. We spatially isolate the active galactic nucleus (AGN) and demonstrate that it is entirely obscured by column density N-H>10(24) cm(-2), detectable in the Chandra bandpass only as a strongly reprocessed weak continuum and a prominent iron Kalpha emission line with equivalent width of 2.4 keV. Most of the soft X-ray emission, both near the AGN and extending over spatial scales of several kpc, is collisionally excited plasma. We attribute this thermal emission to stellar processes. The AGN dominates the X-ray emission only at energies above 4 keV. In the spectral energy distribution that extends to far-infrared wavelengths, nearly all the emergent luminosity below 10 keV is attributable to star formation, not the AGN. C1 Univ Kentucky, Dept Phys & Astron, Lexington, KY 40506 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Johns Hopkins Univ, Dept Phys & Astron, Bloomberg Ctr, Baltimore, MD 21218 USA. Ehime Univ, Fac Sci, Dept Phys, Matsuyama, Ehime 7908577, Japan. Inst Space & Astronaut Sci, Kanagawa 2298510, Japan. RP Univ Kentucky, Dept Phys & Astron, Lexington, KY 40506 USA. EM levenson@pa.uky.edu OI Levenson, Nancy A./0000-0003-4209-639X NR 65 TC 25 Z9 25 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 FEB 10 PY 2004 VL 602 IS 1 BP 135 EP 147 DI 10.1086/380836 PN 1 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 779MT UT WOS:000189304900013 ER PT J AU Colbert, EJM Heckman, TM Ptak, AF Strickland, DK Weaver, KA AF Colbert, EJM Heckman, TM Ptak, AF Strickland, DK Weaver, KA TI Old and young x-ray point source populations in nearby galaxies SO ASTROPHYSICAL JOURNAL LA English DT Article DE X-rays : binaries; X-rays : galaxies ID FORMATION RATE INDICATOR; STAR-FORMATION; STARBURST GALAXIES; IRAS OBSERVATIONS; HOST GALAXIES; BLACK-HOLES; LUMINOSITY; CHANDRA; BINARIES; ULTRAVIOLET AB We have analyzed Chandra ACIS observations of 32 nearby spiral and elliptical galaxies and present the results of 1441 X-ray point sources that were detected in these galaxies. The total point-source X-ray (0.3-8.0 keV) luminosity L-XP is well correlated with the B-band, K-band, and FIR+UV luminosities of spiral host galaxies and is well correlated with the B-band and K-band luminosities of elliptical galaxies. This suggests an intimate connection between L-XP and both the old and young stellar populations, for which K and FIR+UV luminosities are reasonable proxies for the galaxy mass M and star formation rate SFR. We derive proportionality constants alpha=1.3x10(29) ergs s(-1) M-circle dot(-1) and beta=0.7x10(39) ergs s(-1) (M-circle dot yr(-1))(-1), which can be used to estimate the old and young components from M and SFR, respectively. The cumulative X-ray luminosity functions for the point sources have significantly different slopes. For the spiral and starburst galaxies, gammaapproximate to0.6-0.8, and for the elliptical galaxies, gammaapproximate to1.4. This implies that the most luminous point sources-those with L(X)greater than or similar to10(38) ergs s(-1)-dominate L-XP for the spiral and starburst galaxies. Most of the point sources have X-ray colors that are consistent with soft-spectrum (photon index Gammasimilar to1-2) low-mass X-ray binaries, accretion-powered black hole high-mass X-ray binaries (BH HMXBs), or ultraluminous X-ray sources (ULXs, also known as IXOs). We rule out hard-spectrum neutron star HMXBs (e.g., accretion-powered X-ray pulsars) as contributing much to L-XP. Thus, for spirals, L-XP is dominated by ULXs and BH HMXBs. We find no discernible difference between the X-ray colors of ULXs (L(X)greater than or equal to10(39) ergs s(-1)) in spiral galaxies and point sources with LXapproximate to10(38)-10(39) ergs s(-1). We estimate that greater than or similar to20% of all ULXs found in spirals originate from the older (Population II) stellar populations, indicating that many of the ULXs that have been found in spiral galaxies are in fact Population II ULXs, like those in elliptical galaxies. We find that L-XP depends linearly (within uncertainties) on both M and SIR for our sample galaxies (Mless than or equal to10(11) M-circle dot and SFRless than or similar to10 M-circle dot yr(-1)). C1 Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Colbert, EJM (reprint author), Johns Hopkins Univ, Dept Phys & Astron, Homewood Campus,3400 N Charles St, Baltimore, MD 21218 USA. NR 60 TC 153 Z9 153 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 FEB 10 PY 2004 VL 602 IS 1 BP 231 EP 248 DI 10.1086/380899 PN 1 PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 779MT UT WOS:000189304900020 ER PT J AU Lanz, T Brown, TM Sweigart, AV Hubeny, I Landsman, WB AF Lanz, T Brown, TM Sweigart, AV Hubeny, I Landsman, WB TI Flash mixing on the white dwarf cooling curve: Far Ultraviolet Spectroscopic Explorer observations of three He-rich sdB stars SO ASTROPHYSICAL JOURNAL LA English DT Article DE stars : abundances; stars : atmospheres; stars : evolution; stars : horizontal-branch; subdwarfs; ultraviolet : stars ID HORIZONTAL-BRANCH STARS; SUBDWARF-B-STARS; BLANKETED MODEL ATMOSPHERES; GLOBULAR-CLUSTER NGC-2808; EDINBURGH-CAPE SURVEY; MASS-LOSS; SPECTRAL-ANALYSIS; OMEGA-CENTAURI; BLUE STARS; PHOTOMETRY AB We present Far-Ultraviolet Spectroscopic Explorer (FUSE) spectra of three He-rich sdB stars. Two of these stars, PG 1544+488 and JL 87, reveal extremely strong C III lines at 977 and 1176 Angstrom, while the carbon lines are quite weak in the third star, LB 1766. We have analyzed the FUSE data using TLUSTY non-LTE line-blanketed model atmospheres and find that PG 1544+488 has a surface composition of 96% He, 2% C, and 1% N. JL 87 shows a similar surface enrichment of carbon and nitrogen, but some significant fraction of hydrogen still remains in its atmosphere. Finally, LB 1766 has a surface composition devoid of hydrogen and strongly depleted of carbon, indicating that its surface material has undergone CN-cycle processing. We interpret these observations with new evolutionary calculations which suggest that He-rich sdB stars with C-rich compositions are the progeny of stars which underwent a delayed helium-core flash on the white-dwarf cooling curve. During such a flash the interior convection zone will penetrate into the hydrogen envelope, thereby mixing the envelope with the He- and C-rich core. Such "flash-mixed" stars will arrive on the extreme horizontal branch (EHB) with He- and C-rich surface compositions and will be hotter than the hottest canonical (i.e., unmixed) EHB stars. Two types of flash mixing are possible: "deep" and "shallow," depending on whether the hydrogen envelope is mixed deeply into the site of the helium flash or only with the outer layers of the core. Based on both their stellar parameters and surface compositions, we suggest that PG 1544+488 and JL 87 are examples of "deep" and "shallow" flash mixing, respectively. Flash mixing may therefore represent a new evolutionary channel for producing the hottest EHB stars. However, flash mixing cannot explain the abundance pattern in LB 1766, which remains a challenge to current evolutionary models. C1 Univ Maryland, Dept Astron, College Pk, MD 20742 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Space Telescope Sci Inst, Baltimore, MD 21218 USA. Natl Opt Astron Observ, Tucson, AZ 85726 USA. Sci Syst & Applicat Inc, Lanham, MD USA. RP Lanz, T (reprint author), Univ Maryland, Dept Astron, College Pk, MD 20742 USA. EM tlanz@umd.edu; tbrown@stsci.edu; sweigart@bach.gsfc.nasa.gov; hubeny@noao.edu; landsman@mpb.gsfc.nasa.gov OI Brown, Thomas/0000-0002-1793-9968 NR 39 TC 61 Z9 61 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 FEB 10 PY 2004 VL 602 IS 1 BP 342 EP 355 DI 10.1086/380904 PN 1 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 779MT UT WOS:000189304900033 ER PT J AU McAteer, RTJ Gallagher, PT Bloomfield, DS Williams, DR Mathioudakis, M Keenan, FP AF McAteer, RTJ Gallagher, PT Bloomfield, DS Williams, DR Mathioudakis, M Keenan, FP TI Ultraviolet oscillations in the chromosphere of the quiet Sun SO ASTROPHYSICAL JOURNAL LA English DT Article DE methods : statistical; Sun : chromosphere; Sun : oscillations; Sun : photosphere; Sun : UV radiation ID NETWORK BRIGHT POINTS; SOLAR CHROMOSPHERE; TRANSITION REGION; WAVELET ANALYSIS; DYNAMICS; GRAINS; INTERNETWORK; ATMOSPHERE; TRACE; FIELDS AB Quiet-Sun oscillations in the four Transition Region and Coronal Explorer (TRACE) ultraviolet passbands centered on 1700, 1600, 1216, and 1550 Angstrom are studied using a wavelet-based technique. Both network and internetwork regions show oscillations with a variety of periods and lifetimes in all passbands. The most frequent network oscillation has a period of 283 s, with a lifetime of 2-3 cycles in all passbands. These oscillations are discussed in terms of upwardly propagating magnetohydrodynamic wave models. The most frequent internetwork oscillation has a period of 252 s, again with a lifetime of 2-3 cycles, in all passbands. The tendency for these oscillations to recur in the same position is discussed in terms of "persistent flashers." The network contains greater oscillatory power than the internetwork at periods longer than 300 s in the low chromosphere. This value is shown to decrease to 250 s in the high chromosphere. The internetwork also displays a larger number of short-lifetime, long-period oscillations than the network, especially in the low chromosphere. Both network and internetwork regions contain a small number of nonrecurring long-lifetime oscillations. C1 Queens Univ Belfast, Dept Pure & Appl Phys, Belfast BT7 1NN, Antrim, North Ireland. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. UCL, Mullard Space Sci Lab, Dorking RH5 6NT, Surrey, England. RP Queens Univ Belfast, Dept Pure & Appl Phys, Belfast BT7 1NN, Antrim, North Ireland. EM j.mcateer@qub.ac.uk RI McAteer, R. T. James/D-3736-2011; Williams, David/E-6676-2011; Bloomfield, Shaun/G-5809-2011; Gallagher, Peter/C-7717-2011 OI Williams, David/0000-0001-9922-8117; Bloomfield, Shaun/0000-0002-4183-9895; Gallagher, Peter/0000-0001-9745-0400 NR 45 TC 29 Z9 29 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 FEB 10 PY 2004 VL 602 IS 1 BP 436 EP 445 DI 10.1086/380835 PN 1 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 779MT UT WOS:000189304900041 ER PT J AU Desch, SJ Connolly, HC Srinivasan, G AF Desch, SJ Connolly, HC Srinivasan, G TI An interstellar origin for the beryllium 10 in calcium-rich, aluminum-rich inclusions SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmic rays; nuclear reactions, nucleosynthesis, abundances; solar system : formation; stars : formation ID GALACTIC COSMIC-RAYS; SHORT-LIVED NUCLIDES; RADIATION MAGNETOHYDRODYNAMICS CODE; AGE-METALLICITY RELATION; EARLY SOLAR-SYSTEM; 2 SPACE DIMENSIONS; MILKY-WAY DISK; STAR-FORMATION; MOLECULAR CLOUDS; MAGNETIC-FIELDS AB Beryllium 10 is a short-lived radionuclide (t(1/2) = 1.5 Myr) that was incorporated live into calcium-rich, aluminum-rich inclusions (CAIs) at the birth of our solar system. Beryllium 10 is unique among the short-lived radionuclides in that it is formed only by spallation reactions and not by nucleosynthesis, e.g., in a supernova. Recent work by McKeegan, Gounelle, and others has stated that the high initial abundance of Be-10 in CAIs (Be-10/Be-9 approximate to 1 X 10(-3)) cannot be attributed to galactic cosmic rays (GCRs) and therefore concluded that the spallation reactions must have occurred within the solar nebula itself, because of energetic particles emitted by the early Sun. In this paper we reexamine this conclusion. We calculate the contributions of GCRs to the Be-10 abundance in a molecular cloud core as it collapses to form a protostar and protoplanetary disk. We constrain the flux of protons and Be-10 GCRs in the Sun's molecular cloud core 4.5 Gyr ago. We use numerical magnetohydrodynamic simulations of star formation to model the time evolution of the magnetic field strength and column density of gas in a collapsing cloud core. We account for magnetic focusing and magnetic mirroring and the anisotropic distribution of GCR pitch angles in the cloud core. We calculate the rates at which GCR protons and a-particles induce spallation reactions producing Be-10 atoms, and the rates at which GCR Be-10 nuclei are trapped in the cloud core. Accounting also for the decay of Be-10 over the evolution of the cloud core, we calculate the time-varying Be-10/Be-9 ratio. We find that at the time of protostar formation Be-10/Be-9 approximate to 1 x 10(-3), with an uncertainty of about a factor of 3. Spallation reactions account for 20% of the Be-10 in CAls, while trapped GCR Be-10 nuclei account for the other 80%. The initial abundance of Be-10 in CAls is therefore entirely attributable to cosmic rays. We discuss the implications of this finding for the origin of other short-lived radionuclides and for the use of Be-10 as a chronometer. C1 Carnegie Inst Washington, Dept Terr Magnetism, Washington, DC 20015 USA. NASA, Astrobiol Inst, Washington, DC USA. CUNY, Kingsborough Coll, Dept Phys Sci, Brooklyn, NY 11235 USA. Amer Museum Nat Hist, Dept Earth & Planetary Sci, New York, NY 10024 USA. Rutgers State Univ, Dept Geol Sci, Piscataway, NJ 08854 USA. Phys Res Lab, Ahmedabad 380009, Gujarat, India. RP Desch, SJ (reprint author), Arizona State Univ, Dept Phys & Astron, POB 871504, Tempe, AZ 85287 USA. EM desch@dtm.ciw.edu; hconnolly@kbcc.cuny.edu; srini@prl.ernet.in NR 84 TC 71 Z9 71 U1 1 U2 10 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 FEB 10 PY 2004 VL 602 IS 1 BP 528 EP 542 DI 10.1086/380831 PN 1 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 779MT UT WOS:000189304900046 ER PT J AU Hathaway, DH Nandy, D Wilson, RM Reichmann, EJ AF Hathaway, DH Nandy, D Wilson, RM Reichmann, EJ TI Evidence that a deep meridional flow sets the sunspot cycle period (vol 589, pg 665, 2003) SO ASTROPHYSICAL JOURNAL LA English DT Correction C1 NASA, George C Marshall Space Flight Ctr, NSSTC, Huntsville, AL 35812 USA. Mongolian State Univ, Dept Phys, Bozeman, MT USA. RP Hathaway, DH (reprint author), NASA, George C Marshall Space Flight Ctr, NSSTC, Huntsville, AL 35812 USA. EM david.h.hathaway@nasa.gov NR 1 TC 12 Z9 12 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 FEB 10 PY 2004 VL 602 IS 1 BP 543 EP 543 DI 10.1086/379790 PN 1 PG 1 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 779MT UT WOS:000189304900047 ER PT J AU Patel, SK Kouveliotou, C Tennant, A Woods, PM King, A Finger, MH Ubertini, P Winkler, C Courvoisier, TJL van der Klis, M Wachter, S Gaensler, BM Phillips, CJ AF Patel, SK Kouveliotou, C Tennant, A Woods, PM King, A Finger, MH Ubertini, P Winkler, C Courvoisier, TJL van der Klis, M Wachter, S Gaensler, BM Phillips, CJ TI The peculiar X-ray transient IGR J16358-4726 SO ASTROPHYSICAL JOURNAL LA English DT Article DE pulsars : individual (IGR J16358-4726) ID BLACK-HOLE; J16318-4848; IMAGER AB The new transient IGR J16358-4726 was discovered on 2003 March 19 with INTEGRAL. We detected the source serendipitously during our 2003 March 24 observation of SGR 1627-41 with the Chandra X-Ray Observatory at the 1.7 x 10(-10) ergs s(-1) cm(-2) flux level (2-10 keV) with a very high absorption column (N-H = 3.3 x 10(23) cm(-2)) and a hard power-law spectrum of index 0.5(1). We discovered a very strong flux modulation with a period of 5880(50) s and peak-to-peak Pulse fraction of 70(6)% (2-10 keV), clearly visible in the X-ray data. The nature of IGR J16358-4726 remains unresolved. The only neutron star systems known with similar spin periods are low-luminosity persistent wind-fed pulsars; if this is a spin period, this transient is a new kind of object. If this is an orbital period, then the system could be a compact low-mass X-ray binary. C1 Univ Space Res Assoc, Natl Space Sci & Technol Ctr, Huntsville, AL 35805 USA. NASA, George C Marshall Space Flight Ctr, Natl Space Sci & Technol, Huntsville, AL 35805 USA. Univ Leicester, Dept Phys & Astron, Leicester LE1 7RH, Leics, England. Ist Astrofis Spaziale & Fis Cosm, I-00133 Rome, Italy. ESA, European Space Res & Technol Ctr, NL-2201 AZ Noordwijk, Netherlands. ISDC, CH-1290 Versoix, Switzerland. Observ Geneva, CH-1290 Sauverny, Switzerland. Univ Amsterdam, Ctr High Energy Astrophys, NL-1098 SJ Amsterdam, Netherlands. CALTECH, Spitzer Sci Ctr, Pasadena, CA 91125 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Australia Telescope Natl Facil, Epping, NSW 1710, Australia. EM sandeep.patel@nsste.nasa.gov RI Gaensler, Bryan/F-8655-2010 NR 19 TC 44 Z9 44 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 FEB 10 PY 2004 VL 602 IS 1 BP L45 EP L48 DI 10.1086/382210 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 779MU UT WOS:000189305000012 ER PT J AU Procopio, AS Artaxo, P Kaufman, YJ Remer, LA Schafer, JS Holben, BN AF Procopio, AS Artaxo, P Kaufman, YJ Remer, LA Schafer, JS Holben, BN TI Multiyear analysis of amazonian biomass burning smoke radiative forcing of climate SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID SAFARI 2000; AEROSOL; ATMOSPHERE; CARBON AB Seven years analysis of clear-sky aerosol direct radiative forcing is presented for two locations in the Amazon Region heavily impacted by biomass burning emissions. During the dry season, the monthly average direct forcing at the top of the atmosphere, deduced from measurements, varied from -5 to -12 W/m(2) and at the surface from -21 to -74 W/m(2), with the difference associated with absorption of sunlight by the smoke aerosol layer. The spatial distribution of the forcings over Amazonia showed that they affect an area over 1.2-2.6 million square kilometers. C1 Univ Sao Paulo, Inst Fis, Dept Fis Aplicada, BR-05508900 Sao Paulo, Brazil. Univ Sao Paulo, Inst Astron Geofis & Ciencias Atmosfer, Dept Ciencias Atmosfer, Sao Paulo, Brazil. NASA, Goddard Space Flight Ctr, Terr Phys Lab, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. RP Procopio, AS (reprint author), Univ Sao Paulo, Inst Fis, Dept Fis Aplicada, Rua Matao,Travessa R, BR-05508900 Sao Paulo, Brazil. EM aline@if.usp.br RI Procopio, Aline/B-3367-2008; Schafer, Joel/A-3978-2010; Procopio, Aline/L-7483-2013; Artaxo, Paulo/E-8874-2010 OI Procopio, Aline/0000-0002-2326-2500; Artaxo, Paulo/0000-0001-7754-3036 NR 22 TC 43 Z9 46 U1 0 U2 4 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD FEB 10 PY 2004 VL 31 IS 3 AR L03108 DI 10.1029/2003GL018646 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 775PP UT WOS:000189050600001 ER PT J AU Webb, EL Robinson, JA Evangelista, MA AF Webb, EL Robinson, JA Evangelista, MA TI Scanning, compression and land cover classification of astronaut-acquired orbital photographs SO INTERNATIONAL JOURNAL OF REMOTE SENSING LA English DT Article ID SPACE-SHUTTLE PHOTOGRAPHY AB Studies that utilize astronaut-acquired orbital photographs for visual or digital classification require high-quality data to ensure accuracy. The majority of images available must be scanned from film and electronically transferred to scientific users. This study examined the effect of scanning spatial resolution (1200, 2400 pixels per inch (21.2 and 10.6 mum/pixel)), scanning density range option (Auto, Full) and compression ratio (non-lossy: Tagged-Image File Format (TIFF); and lossy: Joint Photographic Experts Group (JPEG) 10:1, 46:1, 83:1) on digital classification results of an orbital photograph from the National Aeronautics and Space Administration (NASA)-Johnson Space Center archive. Qualitative results suggested that 1200 ppi was acceptable for visual interpretative uses for major land cover types. Moreover, Auto scanning density range was superior to Full density range. Quantitative assessment of the processing steps indicated that, while 2400 ppi scanning spatial resolution resulted in more classified polygons as well as a substantially greater proportion of polygons less than or equal to0.2 ha, overall agreement between 1200 ppi and 2400 ppi was quite high. JPEG compression up to approximately 46:1 also did not appear to have a major impact on quantitative classification characteristics. We conclude that both 1200 and 2400 ppi scanning resolutions are acceptable options for this level of land cover classification, as well as a compression ratio at or below approximately 46:1. Auto range density should always be used during scanning because it acquires more of the information from the film. The particular combination of scanning spatial resolution and compression level will require a case-by-case decision and will depend upon memory capabilities, analytical objectives and the spatial properties of the objects in the image. C1 Asian Inst Technol, Sch Environm Resources & Dev, Klongluang 12120, Pathumthani, Thailand. NASA, Lyndon B Johnson Space Ctr, Earth Sci & Image Anal Lab, Lockheed Martin Space Operat, Houston, TX 77058 USA. RP Webb, EL (reprint author), Asian Inst Technol, Sch Environm Resources & Dev, POB 4, Klongluang 12120, Pathumthani, Thailand. RI Webb, Edward/E-8343-2011; OI Webb, Edward/0000-0001-5554-9955; Robinson, Julie/0000-0002-6832-6459 NR 18 TC 0 Z9 0 U1 0 U2 0 PU TAYLOR & FRANCIS LTD PI ABINGDON PA 4 PARK SQUARE, MILTON PARK, ABINGDON OX14 4RN, OXON, ENGLAND SN 0143-1161 J9 INT J REMOTE SENS JI Int. J. Remote Sens. PD FEB 10 PY 2004 VL 25 IS 3 BP 653 EP 667 DI 10.1080/0143116031000139881 PG 15 WC Remote Sensing; Imaging Science & Photographic Technology SC Remote Sensing; Imaging Science & Photographic Technology GA 760QB UT WOS:000187844300011 ER PT J AU Farrell, WM Kaiser, ML Bale, SD Desch, MD Fitzenreiter, RJ Goetz, K Bougeret, JL AF Farrell, WM Kaiser, ML Bale, SD Desch, MD Fitzenreiter, RJ Goetz, K Bougeret, JL TI Relativistic cyclotron resonance condition as applied to Type II interplanetary radio emission SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article DE solar type II emission; solar physics; plasma instabilities ID WIND SPACECRAFT; PLASMA; WAVES; SHOCK AB [1] We demonstrate that energy from energetic electrons upstream of interplanetary (IP) shocks are able to couple directly to the o-mode radio branch via the relativistic cyclotron harmonic resonance interaction, thereby creating the Type II radiation observed from IP shocks. The conditions required for the electron/wave resonance are that the wave frequency, f, lies near the local plasma frequency, f(p), and near (but not exactly at) the cyclotron harmonics, mf(c), where m is the cyclotron harmonic number. We compare the details of this relativistic electron cyclotron harmonic theory with observations in a Type II source region, with good agreement in many areas including the prediction of "Zeeman'' splitting of the Type II emission. Based on the character of the high-resolution emission spectrum, we can narrow the Type II source location to the IP shock foot region and place some general conditions on shock topology required for Type II emission. C1 NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. Univ Minnesota, Sch Phys & Astron, Minneapolis, MN 55455 USA. Observ Paris, Dept Rech Spatiale, F-97005 Meudon, France. RP Farrell, WM (reprint author), NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Code 695, Greenbelt, MD 20771 USA. EM william.farrell@gsfc.nasa.gov RI Bale, Stuart/E-7533-2011; Farrell, William/I-4865-2013 OI Bale, Stuart/0000-0002-1989-3596; NR 13 TC 3 Z9 3 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 FEB 10 PY 2004 VL 109 IS A2 AR A02106 DI 10.1029/2003JA009965 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 775QY UT WOS:000189054400001 ER PT J AU Duxbury, TC Newburn, RL Acton, CH Carranza, E McElrath, TP Ryan, RE Synnott, SP You, TH Brownlee, DE Cheuvront, AR Adams, WR Toro-Allen, SL Freund, S Gilliland, KV Irish, KJ Love, CR McAllister, JG Mumaw, SJ Oliver, TH Perkins, DE AF Duxbury, TC Newburn, RL Acton, CH Carranza, E McElrath, TP Ryan, RE Synnott, SP You, TH Brownlee, DE Cheuvront, AR Adams, WR Toro-Allen, SL Freund, S Gilliland, KV Irish, KJ Love, CR McAllister, JG Mumaw, SJ Oliver, TH Perkins, DE TI Asteroid 5535 Annefrank size, shape, and orientation: Stardust first results SO JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS LA English DT Article DE asteroid; Annefrank; Annefrank size; Annefrank orientation; NASA Stardust mission ID TOPOGRAPHY; 433-EROS AB [1] The NASA Discovery Stardust spacecraft flew by the main belt asteroid 5535 Annefrank at a distance of 3100 km and a speed of 7.4 km/s in November 2002 to test the encounter sequence developed for its primary science target, the comet 81P/Wild 2. During this testing, over 70 images of Annefrank were obtained, taken over a phase angle range from 40 to 140 deg. This viewing showed that Annefrank was at least 6.6 x 5.0 x 3.4 km in size ( diameters), with its shortest dimension normal to its orbit plane. Annefrank is highly angular, with flat appearing surfaces, possibly planes formed when it was fractured off of a larger parent body. For the limited part of the surface seen, Annefrank resembles a triangular prism for the main body, with smaller, rounder bodies, possibly accreted through contact. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Washington, Dept Astron, Seattle, WA 98195 USA. Lockheed Martin Astronaut, Denver, CO 80201 USA. RP Duxbury, TC (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM tduxbury@jpl.nasa.gov NR 17 TC 10 Z9 10 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-PLANET JI J. Geophys. Res.-Planets PD FEB 6 PY 2004 VL 109 IS E2 AR E02002 DI 10.1029/2003JE002108 PG 5 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 775MT UT WOS:000189045500001 ER PT J AU Chen, RH Chaos, M Haddad, GF Mills, TE AF Chen, RH Chaos, M Haddad, GF Mills, TE TI Effects of vortex shedding by particles in acoustical transducers SO JOURNAL OF SOUND AND VIBRATION LA English DT Letter ID SPHERES C1 Univ Cent Florida, Dept Mech Mat & Aerosp Engn, Orlando, FL 32816 USA. NASA, John F Kenney Space Ctr, Kennedy Space Ctr, FL 32899 USA. Engn Technol Inc, Orlando, FL 32826 USA. RP Chen, RH (reprint author), Univ Cent Florida, Dept Mech Mat & Aerosp Engn, Orlando, FL 32816 USA. EM chenrh@mail.ucf.edu NR 16 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 FEB 6 PY 2004 VL 270 IS 1-2 BP 473 EP 479 DI 10.1016/S0022-460X(03)00534-0 PG 7 WC Acoustics; Engineering, Mechanical; Mechanics SC Acoustics; Engineering; Mechanics GA 766HN UT WOS:000188371100029 ER PT J AU Yuan, W Kim, S Sadowy, G Zhang, C Wang, C Steier, WH Fetterman, HR AF Yuan, W Kim, S Sadowy, G Zhang, C Wang, C Steier, WH Fetterman, HR TI Polymeric electro-optic digital optical switches with low switching voltage SO ELECTRONICS LETTERS LA English DT Article AB Digital optical switches based on electro-optic polymers have been designed and fabricated. They are suited for use as spatial switches in optical-controlled phase-array radars. The switches show step-like responses to driving voltages with 7 V switching voltage for dual-arm driving and high extinction ratio. This non-resonant switch design can be driven by push-pull configurations without bias. C1 Univ Calif Los Angeles, Dept Elect Engn, Los Angeles, CA 90095 USA. Jet Prop Lab, Pasadena, CA 91109 USA. Univ So Calif, Dept Chem, Los Angeles, CA 90089 USA. Univ So Calif, Dept Elect Engn, Los Angeles, CA 90089 USA. RP Yuan, W (reprint author), Univ Calif Los Angeles, Dept Elect Engn, 420 Westwood Pl, Los Angeles, CA 90095 USA. EM yuan@ee.ucla.edu NR 4 TC 9 Z9 12 U1 0 U2 3 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 FEB 5 PY 2004 VL 40 IS 3 BP 195 EP 197 DI 10.1049/el:20040116 PG 3 WC Engineering, Electrical & Electronic SC Engineering GA 779QG UT WOS:000189311100030 ER PT J AU Mertens, CJ Schmidlin, FJ Goldberg, RA Remsberg, EE Pesnell, WD Russell, JM Mlynczak, MG Lopez-Puertas, M Wintersteiner, PP Picard, RH Winick, JR Gordley, LL AF Mertens, CJ Schmidlin, FJ Goldberg, RA Remsberg, EE Pesnell, WD Russell, JM Mlynczak, MG Lopez-Puertas, M Wintersteiner, PP Picard, RH Winick, JR Gordley, LL TI SABER observations of mesospheric temperatures and comparisons with falling sphere measurements taken during the 2002 summer MaCWAVE campaign SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID MU-M; MIDDLE ATMOSPHERE; MESOPAUSE; MODEL; EMISSION AB The SABER instrument was launched onboard the TIMED satellite in December 2001. Vertical profiles of kinetic temperature (Tk) are derived from broadband measurements of CO2 15 mum limb emission, in combination with measurements of CO2 4.3 mum limb emission used to derive CO2 volume mixing ratio (vmr). Infrared emission from the CO2 ro-vibrational bands are in non-local thermodynamic equilibrium (non-LTE) in the mesosphere and lower thermosphere (MLT), requiring new radiation transfer and retrieval methods. In this paper we focus on Tk and show some of the first SABER observations of MLT Tk and compare SABER Tk profiles with rocket falling sphere (FS) measurements taken during the 2002 summer MaCWAVE campaign at Andoya, Norway (69 degreesN, 16 degreesE). The comparisons are very encouraging and demonstrate a significant advance in satellite remote sensing of MLT limb emission and the ability to retrieve Tk under extreme non-LTE conditions. C1 NASA, Langley Res Ctr, Atmospher Sci Competency, Hampton, VA 23681 USA. NASA, Wallops Flight Facil, Wallops Isl, VA USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Nomad Res Inc, Arnold, MD USA. Hampton Univ, Hampton, VA 23668 USA. CSIC, Inst Astrofis Andalucia, Granada, Spain. ARCON Corp, Waltham, MA USA. USAF, Res Labs, Hanscom AFB, MA USA. G&A Tech Software, Newport News, VA USA. RP Mertens, CJ (reprint author), NASA, Langley Res Ctr, Atmospher Sci Competency, 21 Langley Blvd,Mail Stop 401B, Hampton, VA 23681 USA. EM c.j.mertens@larc.nasa.gov RI Pesnell, William/D-1062-2012; Goldberg, Richard /E-1881-2012; Mlynczak, Martin/K-3396-2012; Lopez Puertas, Manuel/M-8219-2013 OI Pesnell, William/0000-0002-8306-2500; Lopez Puertas, Manuel/0000-0003-2941-7734 NR 13 TC 122 Z9 123 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 FEB 5 PY 2004 VL 31 IS 3 AR L03105 DI 10.1029/2003GL018605 PG 5 WC Geosciences, Multidisciplinary SC Geology GA 775MA UT WOS:000189043500003 ER PT J AU Jakob, C Pincus, R Hannay, C Xu, KM AF Jakob, C Pincus, R Hannay, C Xu, KM TI Use of cloud radar observations for model evaluation: A probabilistic approach SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE model evaluation; probabilistic verification; cloud radar ID ENSEMBLE PREDICTION SYSTEM; ATMOSPHERIC RADIATION; ECMWF MODEL; SIMULATION; LAYER AB [1] The use of narrow-beam, ground-based active remote sensors ( such as cloud radars and lidars) for long-term observations provides valuable new measurements of the vertical structure of cloud fields. These observations might be quite valuable as tests for numerical simulations, but the vastly different spatial and temporal scales of the observations and simulation must first be reconciled. Typically, the observations are averaged over time and those averages are claimed to be representative of a given model spatial scale, though the equivalence of temporal and spatial averages is known to be quite tenuous. This paper explores an alternative method of model evaluation based on the interpretation of model cloud predictions as probabilistic forecasts at the observation point. This approach requires no assumptions about statistical stationarity and allows the use of an existing, well-developed suite of analytic tools. Time-averaging and probabilistic evaluation techniques are contrasted, and their performance is explored using a set of "perfect'' forecasts and observations extracted from a long cloud system model simulation of continental convection. This idealized example demonstrates that simple time averaging always obscures forecast skill regardless of model domain size. Reliability diagrams are more robust, though scalar scores derived from the diagrams are sensitive to the forecast probability distribution. Forecasts by cloud system and weather forecasting models then provide examples as to how probabilistic techniques might be used in a variety of contexts. C1 Bur Meteorol Res Ctr, Melbourne, Vic 3001, Australia. NOAA, Climate Diagnost Ctr, Cooperat Inst Res Environm Sci, Boulder, CO 80305 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Jakob, C (reprint author), Bur Meteorol Res Ctr, GPO Box 1289K,150 Lonsdale St, Melbourne, Vic 3001, Australia. EM c.jakob@bom.gov.au; robert.pincus@colorado.edu; cecile.hannay@noaa.gov; k.m.xu@larc.nasa.gov RI Xu, Kuan-Man/B-7557-2013; Pincus, Robert/B-1723-2013; Jakob, Christian/A-1082-2010 OI Xu, Kuan-Man/0000-0001-7851-2629; Pincus, Robert/0000-0002-0016-3470; Jakob, Christian/0000-0002-5012-3207 NR 28 TC 23 Z9 23 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 FEB 5 PY 2004 VL 109 IS D3 AR D03202 DI 10.1029/2003JD003473 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 775MJ UT WOS:000189044500002 ER PT J AU Farrugia, CJ Gnavi, G Gratton, FT Matsui, H Torbert, RB Lepping, RP Oieroset, M Lin, RP AF Farrugia, CJ Gnavi, G Gratton, FT Matsui, H Torbert, RB Lepping, RP Oieroset, M Lin, RP TI Electromagnetic ion cyclotron waves in the subsolar region under normal dynamic pressure: Wind observations and theory SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article DE plasma depletion layer (PDL); wave activity in PDL under normal conditions; wind passes near the stagnation streamline ID PLASMA DEPLETION LAYER; TEMPERATURE ANISOTROPY; DAYSIDE MAGNETOPAUSE; EARTHS MAGNETOSHEATH; INSTABILITY; PROTON; TERRESTRIAL; HELIUM; BETA AB We analyze observations on electromagnetic ion cyclotron waves (EICWs) in the plasma depletion layer (PDL) made by Wind on three inbound passes of the magnetosheath near the stagnation streamline and model the observations using recent theory [Gnavi et al., 2000]. While one pass was under substantially high solar wind dynamic pressure P-dyn (similar to6.4 nPa), two passes were under typical P-dyn at 1 AU (similar to2.2 nPa), which allows us to extend the study of EICWs into this lower pressure regime. Two passes were under steady, and one under time varying, conditions. We subdivide the PDL into inner, middle, and outer regions and compute in each the power spectral density (PSD) of the magnetic fluctuations transverse to the background field, using high-resolution (similar to11 samples/s) data from the Magnetic Field Investigation (MFI). The theory solves the kinetic dispersion relation in a plasma composed of electrons, protons, and a particles, each species modeled by bi-Maxwellian distribution functions. Results and trends indicated by the theory are found to be in qualitative agreement with the data. The observations show (1) at the inner PDL position the spectral PSD weakens as P-dyn decreases, and (2) the frequency range of emission shifts downward with diminishing P-dyn. Comparing observations with the classification of spectral types in the PDL under compressed conditions proposed by Anderson et al. [1994], we find a preponderance of so-called low and continuous spectra and only marginally bifurcated spectra with activity peaks below and above the alpha-resonance frequency. In general, as a consequence of smaller P-dyn, near the magnetopause our temperature anisotropies A(p) are at the lower end of values characterizing bifurcated spectra in AMPTE/CCE. C1 Univ New Hampshire, Ctr Space Sci, Inst Study Earth Oceans & Space, Durham, NH 03824 USA. Univ New Hampshire, Dept Phys, Durham, NH 03824 USA. Consejo Nacl Invest Cient & Tecn, Inst Fis Plasma, RA-1428 Buenos Aires, DF, Argentina. Univ Buenos Aires, FCEyN, RA-1428 Buenos Aires, DF, Argentina. NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA. RP Farrugia, CJ (reprint author), Univ New Hampshire, Ctr Space Sci, Inst Study Earth Oceans & Space, Morse Hall,Room 414, Durham, NH 03824 USA. EM charlie.farrugia@unh.edu; gracielagnavi@infip.org; faustogratton@infip.org; hiroshi.matsui@unh.edu; ron.lepping@gsfc.nasa.gov; oieroset@ssl.berkeley.edu; rlin@ssl.berkeley.edu NR 33 TC 5 Z9 5 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 FEB 5 PY 2004 VL 109 IS A2 AR A02202 DI 10.1029/2003JA010104 PG 17 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 775NK UT WOS:000189047400002 ER PT J AU McComas, DJ Schwadron, NA Crary, FJ Elliott, HA Young, DT Gosling, JT Thomsen, MF Sittler, E Berthelier, JJ Szego, K Coates, AJ AF McComas, DJ Schwadron, NA Crary, FJ Elliott, HA Young, DT Gosling, JT Thomsen, MF Sittler, E Berthelier, JJ Szego, K Coates, AJ TI The interstellar hydrogen shadow: Observations of interstellar pickup ions beyond Jupiter SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article DE interstellar hydrogen shadow; Jupiter; Cassini; pickup ions; heliosphere ID SOLAR-WIND; MAGNETIC-FIELD; UP IONS; HELIOSPHERE; HELIUM; DISTRIBUTIONS; ACCELERATION; ULYSSES; CASSINI; FLUCTUATIONS AB This study analyzes the first direct, mass-resolved observations of heliospheric pickup ions beyond the orbit of Jupiter. The Cassini Plasma Spectrometer observes H+, He+, He++, and O+ pickup ions of interstellar origin between 6.4 and 8.2 AU. Cassini's trajectory carries it through the downstream direction where we observe enhancements in the pickup He consistent with gravitational focusing by the Sun. We also show the first in situ observations of an "interstellar hydrogen shadow'' where pickup H is depleted in the region behind the Sun relative to the local interstellar flow. Most H atoms cannot penetrate into this downstream shadow region both because the outward force due to radiation pressure exceeds gravitational attraction at this time and because H atoms trying to enter the shadow must pass close by the Sun where they have a high probability of being ionized and swept out with the solar wind. C1 SW Res Inst, San Antonio, TX 78228 USA. Los Alamos Natl Lab, Los Alamos, NM 87545 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. CNRS, F-94100 St Maur, France. KFKI, Res Inst Particle & Nucl Phys, H-1121 Budapest, Hungary. UCL, Mullard Space Sci Lab, Dorking RH5 6NT, Surrey, England. RP McComas, DJ (reprint author), SW Res Inst, PO Drawer 28510, San Antonio, TX 78228 USA. EM dmccomas@swri.edu; nschwadron@swri.edu; fcrary@swri.edu; helliott@swri.edu; dyoung@swri.edu; jgosling@lanl.gov; mthomsen@lanl.gov; edward.c.sittler@nasa.gov; jean-jacques.berthelier@cetp.ipsl.fr; szego@rmki.kfki.hu; ajc@mssl.ucl.ac.uk RI Coates, Andrew/C-2396-2008 OI Coates, Andrew/0000-0002-6185-3125 NR 42 TC 15 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 FEB 5 PY 2004 VL 109 IS A2 AR A02104 DI 10.1029/2003JA010217 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 775NK UT WOS:000189047400006 ER PT J AU Martin, ST Hung, HM Park, RJ Jacob, DJ Spurr, RJD Chance, KV Chin, M AF Martin, ST Hung, HM Park, RJ Jacob, DJ Spurr, RJD Chance, KV Chin, M TI Effects of the physical state of tropospheric ammonium-sulfate-nitrate particles on global aerosol direct radiative forcing SO ATMOSPHERIC CHEMISTRY AND PHYSICS LA English DT Review ID GENERAL-CIRCULATION MODEL; COMMUNITY CLIMATE MODEL; EFFLORESCENCE RELATIVE HUMIDITIES; AQUEOUS-PHASE-TRANSITIONS; BLACK CARBON AEROSOLS; ANTHROPOGENIC SULFATE; ATMOSPHERIC AEROSOLS; CORUNDUM INCLUSIONS; INORGANIC AEROSOLS; OPTICAL-THICKNESS AB The effect of aqueous versus crystalline sulfate-nitrate-ammonium tropospheric particles on global aerosol direct radiative forcing is assessed. A global three-dimensional chemical transport model predicts sulfate, nitrate, and ammonium aerosol mass. An aerosol thermodynamics model is called twice, once for the upper side (US) and once for lower side (LS) of the hysteresis loop of particle phase. On the LS, the sulfate mass budget is 40% solid ammonium sulfate, 12% letovicite, 11% ammonium bisulfate, and 37% aqueous. The LS nitrate mass budget is 26% solid ammonium nitrate, 7% aqueous, and 67% gas-phase nitric acid release due to increased volatility upon crystallization. The LS ammonium budget is 45% solid ammonium sulfate, 10% letovicite, 6% ammonium bisulfate, 4% ammonium nitrate, 7% ammonia release due to increased volatility, and 28% aqueous. LS aerosol water mass partitions as 22% effloresced to the gas-phase and 78% remaining as aerosol mass. The predicted US/LS global fields of aerosol mass are employed in a Mie scattering model to generate global US/LS aerosol optical properties, including scattering efficiency, single scattering albedo, and asymmetry parameter. Global annual average LS optical depth and mass scattering efficiency are, respectively, 0.023 and 10.7 m(2) (g SO4-2)(-1), which compare to US values of 0.030 and 13.9 m(2) (g SO42-)(-1). Radiative transport is computed, first for a base case having no aerosol and then for the two global fields corresponding to the US and LS of the hysteresis loop. Regional, global, seasonal, and annual averages of top-of-the-atmosphere aerosol radiative forcing on the LS and US (F-L and F-U, respectively, in Wm(-2)) are calculated. Including both anthropogenic and natural emissions, we obtain global annual averages of F-L = - 0.750, F-U = - 0.930, and DeltaF(U,L) = 24% for full sky calculations without clouds and F-L = - 0.485, F-U = - 0.605, and DeltaF(U,L) = 25% when clouds are included. Regionally, DeltaF(U,L) = 48% over the USA, 55% over Europe, and 34% over East Asia. Seasonally, DeltaF(U,L) varies from 18% in DJF to 75% in SON over the USA. The global annual average contribution from anthropogenic aerosol is F-L = - 0.314 and F-U = - 0.404, which yield normalized direct radiative forcings (G) of G(L) = - 205 W (g SO42-)(-1) and G(U) = - 264W (g SO42-)(-1). C1 Harvard Univ, Div Engn & Appl Sci, Cambridge, MA 02138 USA. Harvard Univ, Dept Earth & Planetary Sci, Cambridge, MA 02138 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. Georgia Inst Technol, Sch Earth & Atmospher Sci, Atlanta, GA 30332 USA. NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. RP Martin, ST (reprint author), Harvard Univ, Div Engn & Appl Sci, Cambridge, MA 02138 USA. EM scot_martin@harvard.edu RI Chin, Mian/J-8354-2012; Martin, Scot/G-1094-2015; Park, Rokjin/I-5055-2012; Hung, Hui-Ming/E-3851-2016; OI Martin, Scot/0000-0002-8996-7554; Park, Rokjin/0000-0001-8922-0234; Hung, Hui-Ming/0000-0002-6755-6359; Chance, Kelly/0000-0002-7339-7577 NR 105 TC 100 Z9 101 U1 5 U2 45 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 FEB 4 PY 2004 VL 4 BP 183 EP 214 PG 32 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 771GA UT WOS:000188776200001 ER PT J AU Whang, YC Burlaga, LF Wang, YM Sheeley, NR AF Whang, YC Burlaga, LF Wang, YM Sheeley, NR TI The termination shock near 35 degrees latitude SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID ANOMALOUS COSMIC-RAYS; SOLAR-WIND SPEED; DISTANCE; FLUX; AU AB The termination shock moves outwards and inwards over timescales of a solar cycle in response to the variations in the average solar wind speed. The amplitude is greater than 50 AU near 35degrees latitude; the maximum (minimum) distance occurs during the rising (declining) phase of the solar cycle. Shock parameters are distinctly different when the shock moves outwards or inwards. During the period of high-speed (low-speed) solar wind, the shock moves outward ( inward) and the shock is weaker (stronger). This study assumes that the first crossing of Voyager 1 with the termination shock occurred at 85.5 AU on 2002.6. If Voyager 1 did cross the shock in 2002.6, the spacecraft would likely cross the shock at least two more times before 2010, but no second crossing would occur close to 2003.1. If Voyager 1 did not cross the shock in mid-2002, it might still do so before 2005. C1 Catholic Univ Amer, Washington, DC 20064 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. USN, Res Lab, Washington, DC 20375 USA. RP Catholic Univ Amer, Washington, DC 20064 USA. EM whang@cua.edu NR 14 TC 21 Z9 21 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 FEB 4 PY 2004 VL 31 IS 3 AR L03805 DI 10.1029/2003GL018679 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 775LZ UT WOS:000189043300003 ER PT J AU Stimpfle, RM Wilmouth, DM Salawitch, RJ Anderson, JG AF Stimpfle, RM Wilmouth, DM Salawitch, RJ Anderson, JG TI First measurements of ClOOCl in the stratosphere: The coupling of ClOOCl and ClO in the Arctic polar vortex SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE stratosphere; photochemistry; chlorine dimer ID ABSORPTION CROSS-SECTIONS; CHLORINE OXIDE DIMER; IN-SITU MEASUREMENTS; NASA ER-2 AIRCRAFT; OZONE LOSS; ANTARCTIC OZONE; SELF-REACTION; VIBRATIONAL-SPECTRA; WINTER; DEPLETION AB The first measurements of ClOOCl in the stratosphere have been acquired from a NASA ER-2 aircraft, deployed from Kiruna, Sweden (68degreesN, 21degreesE), during the joint SOLVE/THESEO-2000 mission of the winter of 1999/2000. ClOOCl is detected by thermal dissociation into two ClO fragments that are measured by the well-known technique of chemical conversion, vacuum ultraviolet resonance fluorescence. Ambient ClO is detected simultaneously. Observations of the ratio [ClOOCl]/[ClO](2) (estimated uncertainty of +/-25%, 1 sigma) are used with a time-dependent photochemical model, to test the model representation of the ratios of kinetic parameters J/k(Prod) and k(Loss)/k(Prod) for day and nighttime observations, respectively. Here, k(Prod) and k(Loss) are the rate constants for ClOOCl production and loss, respectively, and J is the photolysis rate of ClOOCl. The observations are in good agreement with J based upon the 2002 JPL recommended cross sections for ClOOCl [Sander et al., 2003], if the true value of k(Prod) is given by either the 2000 JPL recommendation [Sander et al., 2000] or the work of Trolier et al. [1990]. The larger values of k(Prod) given by Bloss et al. [2001] and the 2002 JPL recommendation are consistent with the observations only if J is increased by a significant amount. This is accomplished if J is calculated with the larger ClOOCl cross sections measured by Burkholder et al. [ 1990]. The J values for ClOOCl based on the Huder and DeMore [1995] cross sections are too small, by factors of similar to1.6 to 2.5 for all values of k(Prod), based on the observations. Nighttime results suggest that, for 190 < T < 200 K, the values for K-Eq (the equilibrium constant, equal to the ratio of k(Prod)/k(Loss)) of Cox and Hayman [1988] and Avallone and Toohey [2001] are in best agreement with the observations. C1 Harvard Univ, Dept Chem & Biol Chem, Cambridge, MA 02138 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Stimpfle, RM (reprint author), Harvard Univ, Dept Chem & Biol Chem, Cambridge, MA 02138 USA. EM stimpfle@huarp.harvard.edu RI Salawitch, Ross/B-4605-2009 OI Salawitch, Ross/0000-0001-8597-5832 NR 60 TC 62 Z9 62 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 FEB 4 PY 2004 VL 109 IS D3 AR D03301 DI 10.1029/2003JD003811 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 775MG UT WOS:000189044300001 ER PT J AU Neugebauer, M AF Neugebauer, M TI Anisotropy and Alfvenicity of hourly fluctuations in the fast polar solar wind SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article DE solar wind; Alfven waves; anisotropy; Ulysses ID MAGNETIC-FIELD FLUCTUATIONS; HIGH HELIOGRAPHIC LATITUDES; MINIMUM-VARIANCE; ULYSSES OBSERVATIONS; INNER HELIOSPHERE; TURBULENCE; WAVES; DISCONTINUITIES; EVOLUTION; STREAMS AB [1] Ulysses magnetic and plasma data obtained in the fast polar solar wind are used to study the nature of fluctuations in the frequency range between the turbulent inertial range and the lower-frequency range dominated by quasi-static structures originating at the Sun. For daily variations of hourly averages of the magnetic field components the anisotropy of the fluctuations is less than in the higher-frequency range, and the minimum variance direction loses its alignment with the magnetic field in favor of a more radial direction as the solar distance increases. The anisotropy of the magnetic fluctuations also increases with solar distance, while the Alfvenicity, as measured by the correlation of the field and velocity components, decreases. Most of the observed frequency and distance trends are similar to those observed in fast solar wind streams in the ecliptic, despite the difference in stream structure between high and low latitudes. One major difference from higher-frequency ( inertial range) variations at high latitudes is the continuing decline of the correlation between velocity and field vectors between 2 and 4.5 AU. It is suggested that the relative contribution of discontinuities and planar magnetic structures grows with solar distance relative to the contribution of Alfven waves. C1 Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. CALTECH, Jet Prop Lab, Pasadena, CA USA. RP Neugebauer, M (reprint author), Univ Arizona, Lunar & Planetary Lab, 1629 E Univ Blvd, Tucson, AZ 85721 USA. EM mneugeb@lpl.arizona.edu NR 29 TC 11 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-SPACE JI J. Geophys. Res-Space Phys. PD FEB 4 PY 2004 VL 109 IS A2 AR A02101 DI 10.1029/2003JA009947 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 775NH UT WOS:000189047200001 ER PT J AU Vongsouthy, C Stenger-Nguyen, PA Nguyen, HV Nguyen, PH Huang, MC Alexander, RG AF Vongsouthy, C Stenger-Nguyen, PA Nguyen, HV Nguyen, PH Huang, MC Alexander, RG TI Challenges of assuring crew safety in space shuttle missions with international cargoes SO ACTA ASTRONAUTICA LA English DT Article AB The top priority in America's manned space flight program is the assurance of crew and vehicle safety. This priority gained greater focus during and after the Space Shuttle retum-to-flight mission (STS-26). One of the interesting challenges has been to assure crew safety and adequate protection of the Space Shuttle, as a national resource, from increasingly diverse cargoes and operations. The control of hazards associated with the deployment of complex payloads and cargoes has involved many international participants. These challenges are examined in some detail along with examples of how crew safety has evolved in the manned space program and how the international partners have addressed various scenarios involving control and mitigation of potential hazards to crew and vehicle safety. (C) 2003 Published by Elsevier Ltd. C1 Boeing N Amer Inc, Reusable Space Syst, Downey, CA USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Vongsouthy, C (reprint author), Boeing N Amer Inc, Reusable Space Syst, Downey, CA USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0094-5765 J9 ACTA ASTRONAUT JI Acta Astronaut. PD FEB PY 2004 VL 54 IS 3 BP 215 EP 219 DI 10.1016/S0094-5765(02)00295-3 PG 5 WC Engineering, Aerospace SC Engineering GA 752HQ UT WOS:000187155400008 PM 14606499 ER PT J AU Johnson, NL AF Johnson, NL TI The world state of orbital debris measurements and modeling SO ACTA ASTRONAUTICA LA English DT Article AB For more than 20 years orbital debris research around the world has been striving to obtain a sharper, more comprehensive picture of the near-Earth artificial satellite environment. Whereas significant progress has been achieved through better organized and funded programs and with the assistance of advancing technologies in both space surveillance sensors and computational capabilities, the potential of measurements and modeling of orbital debris has yet to be realized. Greater emphasis on a systems-level approach to the characterization and projection of the orbital debris environment would prove beneficial. On-going space surveillance activities, primarily from terrestrial-based facilities, are narrowing the uncertainties of the orbital debris population for objects greater than 2 mm in LEO and offer a better understanding of the GEO regime down to 10 cm diameter objects. In situ data collected in LEO is limited to a narrow range of altitudes and should be employed with great care. Orbital debris modeling efforts should place high priority on improving model fidelity, on clearly and completely delineating assumptions and simplifications, and on more thorough sensitivity studies. Most importantly, however, greater communications and cooperation between the measurements and modeling communities are essential for the efficient advancement of the field. The advent of the Inter-Agency Space Debris Coordination Committee (IADC) in 1993 has facilitated this exchange of data and modeling techniques. A joint goal of these communities should be the identification of new sources of orbital debris. Published by Elsevier Ltd. C1 NASA, Lyndon B Johnson Space Ctr, Orbital Debris Program Off, Houston, TX 77058 USA. RP Johnson, NL (reprint author), NASA, Lyndon B Johnson Space Ctr, Orbital Debris Program Off, Mail Code SX, Houston, TX 77058 USA. EM nicholas.l.johnson1@jsc.nasa.gov NR 0 TC 4 Z9 4 U1 0 U2 2 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0094-5765 J9 ACTA ASTRONAUT JI Acta Astronaut. PD FEB PY 2004 VL 54 IS 4 BP 267 EP 272 DI 10.1016/S0094-5765(02)00305-3 PG 6 WC Engineering, Aerospace SC Engineering GA 766UY UT WOS:000188395000005 ER PT J AU Seastrom, JW Peercy, RL Johnson, GW Sotnikov, BJ Brukhanov, N AF Seastrom, JW Peercy, RL Johnson, GW Sotnikov, BJ Brukhanov, N TI Risk management in international manned space program operations SO ACTA ASTRONAUTICA LA English DT Article AB New, innovative joint safety policies and requirements were developed in support of the Shuttle/Mir program, which is the first phase of the International Space Station program. This work has resulted in a joint multinational analysis culminating in joint certification for mission readiness. For these planning and development efforts, each nation's risk programs and individual safety practices had to be integrated into a comprehensive and compatible system that reflects the joint nature of the endeavor. This paper highlights the major incremental steps involved in planning and program integration during development of the Shuttle/Mir program. It traces the transition from early development to operational status and highlights the valuable lessons learned that apply to the International Space Station program (Phase 2). Also examined are external and extraneous factors that affected mission operations and the corresponding solutions to ensure safe and effective Shuttle/Mir missions. (C) 2003 Published by Elsevier Ltd. C1 Boeing N Amer Inc, Reusable Space Syst, Downey, CA USA. NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. Rocket Space Corp Energia, Moscow, Russia. RP Seastrom, JW (reprint author), Boeing N Amer Inc, Reusable Space Syst, Downey, CA USA. NR 2 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 FEB PY 2004 VL 54 IS 4 BP 273 EP 279 DI 10.1016/S0094-5765(02)00301-6 PG 7 WC Engineering, Aerospace SC Engineering GA 766UY UT WOS:000188395000006 PM 14692418 ER PT J AU Vander Wal, RL Hall, LJ AF Vander Wal, RL Hall, LJ TI Demonstration of carbon nanotube coated metals reinforcing polymer matrix composites SO ADVANCED ENGINEERING MATERIALS LA English DT Article ID CHEMICAL-VAPOR-DEPOSITION; FLAME SYNTHESIS; CATALYTIC GROWTH; NANOFIBERS; FE; NANOPARTICLES; PARTICLES; FILAMENTS; CO C1 NCMR NASA Glenn, Cleveland, OH 44135 USA. RP Vander Wal, RL (reprint author), NCMR NASA Glenn, MS 110-3,21000 Brookpk Rd, Cleveland, OH 44135 USA. EM randy@rvander.grc.nasa.gov NR 36 TC 7 Z9 7 U1 2 U2 6 PU WILEY-V C H VERLAG GMBH PI WEINHEIM PA PO BOX 10 11 61, D-69451 WEINHEIM, GERMANY SN 1438-1656 J9 ADV ENG MATER JI Adv. Eng. Mater. PD FEB PY 2004 VL 6 IS 1-2 BP 48 EP 52 DI 10.1002/adem.200300514 PG 5 WC Materials Science, Multidisciplinary SC Materials Science GA 801DH UT WOS:000220076100012 ER PT J AU Jones, MG Watson, WR Tracy, MB Parrott, TL AF Jones, MG Watson, WR Tracy, MB Parrott, TL TI Comparison of two waveguide methods for educing liner impedance in grazing flow SO AIAA JOURNAL LA English DT Article ID ACOUSTIC-IMPEDANCE; PLUG FLOW; DUCTS; SOUND; UNIFORM AB Acoustic measurements taken with several liners in a flow impedance tube are used to assess two waveguide methods, the single mode method (SMM) and the finite element method (FEM), for impedance eduction in the presence of uniform grazing flow. Both methods use complex acoustic pressure data acquired over the liner length to educe the liner impedance. The SMM is based on the assumption that the sound pressure level and phase decay rates of a single progressive mode can be extracted from the measured complex acoustic pressures. No a priori assumptions are made in the FEM regarding the measured data. For no-flow conditions, the accuracy of each method is demonstrated by the excellent agreement between no-flow impedances educed in a grazing incidence tube and those acquired in a normal incidence tube. For grazing flow conditions (Mach numbers up to 0.5), the relative accuracy of the two waveguide methods is demonstrated by comparing the impedances educed with the FEM to the corresponding results for the SMM. Significant discrepancies occur for both methods for tests conducted at 0.5 kHz. Possible explanations for these discrepancies are explored with, as yet, no clear answer. Above. 0.5 kHz, the results indicate the SMM can be used when the acoustic pressure. profile is dominated by a single progressive mode, whereas the FEM can be used for all cases. C1 NASA, Langley Res Ctr, Struct Acoust Branch, Aerodynam Aerothermodynam & Acoust Competency, Hampton, VA 23681 USA. NASA, Langley Res Ctr, Computat Modeling & Simulat Branch, Aerodynam Aerothermodynam & Acoust Competency, Hampton, VA 23681 USA. NASA, Langley Res Ctr, Aeroacoust Branch, Aerodynam Aerothermodynam & Acoust Competency, Hampton, VA 23681 USA. RP Jones, MG (reprint author), NASA, Langley Res Ctr, Struct Acoust Branch, Aerodynam Aerothermodynam & Acoust Competency, Hampton, VA 23681 USA. NR 16 TC 9 Z9 9 U1 1 U2 2 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0001-1452 J9 AIAA J JI AIAA J. PD FEB PY 2004 VL 42 IS 2 BP 232 EP 240 DI 10.2514/1.9092 PG 9 WC Engineering, Aerospace SC Engineering GA 776YV UT WOS:000189147700005 ER PT J AU Scott, JR Kreider, KL Heminger, JA AF Scott, JR Kreider, KL Heminger, JA TI Evaluation of radiation boundary conditions for the gust response problem SO AIAA JOURNAL LA English DT Article; Proceedings Paper CT AIAA/CEAS 8th Aeroacoustics Conference CY JUN 17-19, 2002 CL Breckenridge, CO SP Amer Inst Aeronaut & Astronaut, CEAS ID COMPUTATIONAL AEROACOUSTICS; EQUATIONS AB The performances of the Sommerfeld, Bayliss-Turkel order-one, and Hagstrom-Hariharan order-one radiation boundary conditions for the single airfoil gust response problem are evaluated. The main objective is to assess quantitatively the accuracy, grid sensitivity, and computational efficiency of each boundary condition. To this end, a matrix of test problems is constructed, and each boundary condition is extensively tested on a large variety of grids. By the use of precise error norms and analytical solutions, it is determined that the Hagstrom-Hariharan condition is the most accurate condition, whereas the Bayliss-Turkel and Hagstrom-Hariharan conditions are about equally insensitive to grid changes. The Sommerfeld and Bayliss-Turkel conditions are the most computationally efficient. Overall, the Bayliss-Turkel condition appears to offer the best combination of accuracy and computational efficiency. C1 NASA, John H Glenn Res Ctr, Acoust Branch, Cleveland, OH 44135 USA. Univ Akron, Dept Theoret & Appl Math, Akron, OH 44325 USA. RP Scott, JR (reprint author), NASA, John H Glenn Res Ctr, Acoust Branch, 21000 Brookpk Rd, Cleveland, OH 44135 USA. EM James.R.Scott@nasa.gov; Kreider@math.uakron.edu; heminger@amrl.uakron.edu NR 20 TC 1 Z9 1 U1 0 U2 1 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0001-1452 J9 AIAA J JI AIAA J. PD FEB PY 2004 VL 42 IS 2 BP 249 EP 254 DI 10.2514/1.1862 PG 6 WC Engineering, Aerospace SC Engineering GA 776YV UT WOS:000189147700007 ER PT J AU You, DH Mittal, R Wang, M Moin, P AF You, DH Mittal, R Wang, M Moin, P TI Computational methodology for large-eddy simulation of tip-clearance flows SO AIAA JOURNAL LA English DT Article ID COMPRESSOR CASCADE; CIRCULAR-CYLINDER; REYNOLDS-NUMBERS; VORTEX; NOISE; STAGE AB A large-eddy-simulation-based flow solver that combines an immersed-boundary technique with a curvilinear structured grid has been developed to study the temporal and spatial dynamics of an incompressible rotor-tip-clearance flow. The overall objective of these simulations is to determine the underlying mechanisms for low-pressure fluctuations downstream of the rotor near the end wall. Salient features of the numerical methodology, including the mesh topology, the immersed boundary method, the treatment of numerical instability for nondissipalive schemes on highly skewed meshes, and the parallelization of the code for shared memory computer platforms, are discussed. The computational approach is shown to be capable of capturing the evolution of the highly complicated flowfield characterized by the interaction of distinct blade-associated vortical structures with the turbulent end-wall boundary layer. Simulation results are compared with experiments, and qualitative as well as quantitative agreement is observed. C1 Stanford Univ, Dept Mech Engn, Stanford, CA 94305 USA. George Washington Univ, Dept Mech & Aerosp Engn, Washington, DC 20052 USA. Stanford Univ, Dept Mech Engn, Stanford, CA 94305 USA. Stanford Univ, NASA, Ames Res Ctr, Ctr Turbulence Res, Stanford, CA 94305 USA. RP You, DH (reprint author), Stanford Univ, Dept Mech Engn, Stanford, CA 94305 USA. EM dyou@stanford.edu RI Mittal, Rajat/A-3009-2010; You, Donghyun/F-8961-2011; Wang, Meng/C-1622-2012; OI Mittal, Rajat/0000-0002-8107-9499 NR 29 TC 50 Z9 51 U1 3 U2 17 PU AMER INST AERONAUT ASTRONAUT PI RESTON PA 1801 ALEXANDER BELL DRIVE, STE 500, RESTON, VA 22091-4344 USA SN 0001-1452 J9 AIAA J JI AIAA J. PD FEB PY 2004 VL 42 IS 2 BP 271 EP 279 DI 10.2514/1.2626 PG 9 WC Engineering, Aerospace SC Engineering GA 776YV UT WOS:000189147700010 ER PT J AU De, S Heaney, PJ Fei, YW Vicenzi, EP AF De, S Heaney, PJ Fei, YW Vicenzi, EP TI Microstructural study of synthetic sintered diamond and comparison with carbonado, a natural polycrystalline diamond SO AMERICAN MINERALOGIST LA English DT Article ID HIGH-PRESSURE; SUPERHARD MATERIALS; DIRECT CONVERSION; STATIC PRESSURE; DEFORMATION; GRAPHITE; TEMPERATURE; CONSTRAINTS; MINERALOGY; PARTICLES AB Efforts to simulate the extreme toughness of the polycrystalline diamond variety known as carbonado typically entail the sintering of diamond powders in the presence of metal solvent-catalysts. In this study, we have attempted to duplicate the carbonado microstructure by sintering diamond powders without catalysts in a multi-anvil press at pressures of 6 to 9 GPa, temperatures of 1200 to 1800 degreesC, and times up to 6 h. The resultant microstructural defect assemblages for each experimental condition were characterized by transmission electron microscopy (TEM). Despite the absence of catalysts, sintered compacts were successfully produced for all runs, though intergranular porosity was significantly higher than that observed in natural carbonado. Primary grain sizes were reduced by more than 50% from their original dimensions in some experiments due to surface fracturing and abrasion, and aperiodic slip planes rigorously parallel to {111} consistently emerged in high densities, with lamellar spacings of 3 to 30 nm. In addition, sintering over all conditions produced polysynthetic spinel twinning in close association with the partial slip defects. Compacts compressed at 8 GPa produced some euhedral crystals with very low dislocation densities surrounded by grains in which dislocation densities were quite high. In addition, curviplanar defects loosely constrained to {111} were visible within some specimens sintered at the highest pressures. These textures resembled the polygonalization fabrics and defect microstructures observed in natural carbonado (De et al. 1998), and the appearance of these features suggests that our experiments at their most extreme pressure and temperature parameters reproduced carbonado-like defect assemblages. The formation of such textures in quasi-hydrostatic experiments suggests that shock metamorphism is not required to produce the periodic defect lamellae observed in carbonado. C1 NASA, Ames Res Ctr, Exobiol Branch, Moffett Field, CA 94035 USA. Penn State Univ, Dept Geosci, University Pk, PA 16802 USA. Carnegie Inst Sci, Geophys Lab, Washington, DC 20015 USA. Smithsonian Inst, Dept Mineral Sci, Washington, DC 20560 USA. RP De, S (reprint author), NASA, Ames Res Ctr, Exobiol Branch, Moffett Field, CA 94035 USA. EM sde@alumni.princeton.edu RI Fei, Yingwei/F-3709-2011 OI Fei, Yingwei/0000-0001-9955-5353 NR 46 TC 9 Z9 9 U1 0 U2 5 PU MINERALOGICAL SOC AMER PI CHANTILLY PA 3635 CONCORDE PKWY STE 500, CHANTILLY, VA 20151-1125 USA SN 0003-004X EI 1945-3027 J9 AM MINERAL JI Am. Miner. PD FEB-MAR PY 2004 VL 89 IS 2-3 BP 438 EP 446 PG 9 WC Geochemistry & Geophysics; Mineralogy SC Geochemistry & Geophysics; Mineralogy GA 776HU UT WOS:000189111200025 ER PT J AU Miller, SR Bebout, BM AF Miller, SR Bebout, BM TI Variation in sulfide tolerance of photosystem II in phylogenetically diverse cyanobacteria from sulfidic habitats SO APPLIED AND ENVIRONMENTAL MICROBIOLOGY LA English DT Article ID BLUE-GREEN-ALGAE; ANOXYGENIC PHOTOSYNTHESIS; CHLOROPHYLL FLUORESCENCE; OSCILLATORIA-LIMNETICA; ELECTRON-TRANSPORT; INTERSPECIFIC DATA; HYDROGEN-SULFIDE; HOT SPRINGS; PHYLOGENY; STRAINS AB Physiological and molecular phylogenetic approaches were used to investigate variation among 12 cyanobacterial strains in their tolerance of sulfide, an inhibitor of oxygenic photosynthesis. Cyanobacteria from sulfidic habitats were found to be phylogenetically diverse and exhibited an approximately 50-fold variation in photosystem II performance in the presence of sulfide. Whereas the degree of tolerance was positively correlated with sulfide levels in the environment, a strain's phenotype could not be predicted from the tolerance of its closest relatives. These observations suggest that sulfide tolerance is a dynamic trait primarily shaped by environmental variation. Despite differences in absolute tolerance, similarities among strains in the effects of sulfide on chlorophyll fluorescence induction indicated a common mode of toxicity. Based on similarities with treatments known to disrupt the oxygen-evolving complex, it was concluded that sulfide toxicity resulted from inhibition of the donor side of photosystem II. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Miller, SR (reprint author), Univ Montana, Div Biol Sci, 32 Campus Dr,4824, Missoula, MT 59812 USA. EM scott.miller@mso.umt.edu NR 39 TC 33 Z9 35 U1 3 U2 8 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 FEB PY 2004 VL 70 IS 2 BP 736 EP 744 DI 10.1128/AEM.70.2.736-744.2004 PG 9 WC Biotechnology & Applied Microbiology; Microbiology SC Biotechnology & Applied Microbiology; Microbiology GA 772RK UT WOS:000188854900013 PM 14766549 ER PT J AU Londry, KL Jahnke, LL Marais, DJD AF Londry, KL Jahnke, LL Marais, DJD TI Stable carbon isotope ratios of lipid biomarkers of sulfate-reducing bacteria SO APPLIED AND ENVIRONMENTAL MICROBIOLOGY LA English DT Article ID MONOXIDE DEHYDROGENASE PATHWAY; ANAEROBIC METHANE OXIDATION; FATTY-ACIDS; DESULFOBACTERIUM-AUTOTROPHICUM; DESULFOVIBRIO-DESULFURICANS; METHANOTROPHIC BACTERIA; OLIGONUCLEOTIDE PROBES; MICROBIAL COMMUNITY; SP-NOV; SEDIMENTS AB We examined the potential use of natural-abundance stable carbon isotope ratios of lipids for determining substrate usage by sulfate-reducing bacteria (SRB). Four SRB were grown under autotrophic, mixotrophic, or heterotrophic growth conditions, and the delta(13)C values of their individual fatty acids (FA) were determined. The FA were usually C-13 depleted in relation to biomass, with Deltadelta(13)C((FA - biomass)) of -4 to -17parts per thousand; the greatest depletion occurred during heterotrophic growth. The exception was Desulfotomaculum acetoxidans, for which substrate limitation resulted in biomass and FA becoming isotopically heavier than the acetate substrate. The delta(13)C values of FA in Desulfotomaculum acetoxidans varied with the position of the double bond in the monounsaturated C-16 and C-18 FA, with FA becoming progressively more C-13 depleted as the double bond approached the methyl end. Mixotrophic growth of Desulfovibrio desulfuricans resulted in little depletion of the i17:1 biomarker relative to biomass or acetate, whereas growth with lactate resulted in a higher proportion of i17:1 with a greater depletion in C-13. The relative abundances of 10Me16:0 in Desulfobacter hydrogenophilus and Desulfobacterium autotrophicum were not affected by growth conditions, yet the Deltadelta(13)C((FA - substrate)) values of 10Me16:0 were considerably greater during autotrophic growth. These experiments indicate that FA delta(13)C values can be useful for interpreting carbon utilization by SRB in natural environments. C1 Univ Manitoba, Dept Microbiol, Winnipeg, MB R3T 2N2, Canada. NASA, Ames Res Ctr, Exobiol Branch, Moffett Field, CA 94035 USA. RP Londry, KL (reprint author), Univ Manitoba, Dept Microbiol, Winnipeg, MB R3T 2N2, Canada. EM londryk@cc.umanitoba.ca NR 40 TC 83 Z9 86 U1 1 U2 26 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 FEB PY 2004 VL 70 IS 2 BP 745 EP 751 DI 10.1128/AEM.70.2.745-751.2004 PG 7 WC Biotechnology & Applied Microbiology; Microbiology SC Biotechnology & Applied Microbiology; Microbiology GA 772RK UT WOS:000188854900014 PM 14766550 ER PT J AU Mao, JP Kawa, SR AF Mao, JP Kawa, SR TI Sensitivity studies for space-based measurement of atmospheric total column carbon dioxide by reflected sunlight SO APPLIED OPTICS LA English DT Article ID ACCURATE TRANSMITTANCE MODEL; MOLECULAR LINE ABSORPTION; RADIATIVE-TRANSFER; ABSORBING GAS; SCATTERING ATMOSPHERE; COMPUTATIONALLY FAST; SOURCE INVERSIONS; COOLING RATES; CO2; BAND AB The feasibility of making space-based carbon dioxide (CO2) measurements for global and regional carbon-cycle studies is explored. With the proposed detection method, we use absorption of reflected sunlight near 1.58 mum. The results indicate that the small (similar to1%) changes in CO2 near the Earth's surface are detectable provided that an adequate sensor signal-to-noise ratio and spectral resolution are achievable. Modification of the sunlight path by scattering of aerosols and cirrus clouds could, however, lead to systematic errors in the CO2 column retrieval; therefore ancillary aerosol and cloud data are important to reduce errors. Precise measurement of surface pressure and good knowledge of the atmospheric temperature profile are also required. (C) 2004 Optical Society of America. C1 Sci Syst & Applicat Inc, Lanham, MD 20706 USA. NASA, Goddard Space Flight Ctr, Atmospher Chem & Dynam Branch, Greenbelt, MD 20771 USA. RP Sci Syst & Applicat Inc, 10210 Greenbelt Rd,Suite 400, Lanham, MD 20706 USA. EM mao@qhearts.gsfe.nasa.gov RI Kawa, Stephan/E-9040-2012 NR 50 TC 81 Z9 100 U1 2 U2 13 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 FEB 1 PY 2004 VL 43 IS 4 BP 914 EP 927 DI 10.1364/AO.43.000914 PG 14 WC Optics SC Optics GA 768CP UT WOS:000188510900026 PM 14960086 ER PT J AU Walsh, BM Barnes, NP AF Walsh, BM Barnes, NP TI Comparison of Tm : ZBLAN and Tm : silica fiber lasers; Spectroscopy and tunable pulsed laser operation around 1.9 mu m SO APPLIED PHYSICS B-LASERS AND OPTICS LA English DT Article ID DOPED FLUOROZIRCONATE FIBER; DIODE-PUMPED OPERATION; RARE-EARTH IONS; OPTICAL-PROPERTIES; GLASS; EFFICIENT; LIYF4; TM-3+ AB Tm-doped ZBLAN and Tm-doped silica glass are compared spectroscopically and the fiber lasing of the Tm F-3(4) -->H-3(6) transition around 1.9 mum in ZBLAN and silica fibers is compared. The spectroscopy of these materials indicates that Tm:ZBLAN possesses advantages over Tm:silica glass due to the lower phonon energies. The phonon energy in these glass hosts influences both the pump manifold lifetime, the Tm H-3(4), and the upper laser manifold lifetime, the Tm F-3(4). The maximum phonon energy in Tm:ZBLAN, similar to500 cm(-1) , compared to Tm:silica, similar to1100 cm(-1), leads to better Tm-Tm self quenching towards populating the Tm F-3(4), as well as better Tm F-3(4)-->H-3(6) quantum efficiency. A spectroscopic analysis using the Judd-Ofelt theory and measured lifetimes are used to assess the merits of Tm:ZBLAN over Tm:silica as a fiber laser material. Diode-pumped fiber lasing experiments show that Tm:ZBLAN possesses advantages over Tm:silica that are believed to be due to a lower phonon energy. Data is presented for launched pump energy versus laser energy, fiber length versus slope efficiency, and output mirror reflectivity versus slope efficiency. Tm:ZBLAN is demonstrated to possess higher slope efficiencies and lower thresholds, than Tm:silicate. A grating tuned Tm:ZBLAN laser is also demonstrated for tunable operation between 1.893 mum and 1.955 mum. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Walsh, BM (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. EM Brian.M.Walsh@nasa.gov NR 28 TC 86 Z9 91 U1 3 U2 24 PU SPRINGER-VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0946-2171 J9 APPL PHYS B-LASERS O JI Appl. Phys. B-Lasers Opt. PD FEB PY 2004 VL 78 IS 3-4 BP 325 EP 333 DI 10.1007/s00340-003-1393-2 PG 9 WC Optics; Physics, Applied SC Optics; Physics GA 801HI UT WOS:000220086600014 ER PT J AU Vander Wal, RL Tomasek, AJ Street, K Hull, DR Thompson, WK AF Vander Wal, RL Tomasek, AJ Street, K Hull, DR Thompson, WK TI Carbon nanostructure examined by lattice fringe analysis of high-resolution transmission electron microscopy images SO APPLIED SPECTROSCOPY LA English DT Article DE transmission electron microscopy; TEM; image; analysis; Raman; soot; carbon; graphitization ID DIFFUSION FLAMES; COAL COMBUSTION; SOOT FORMATION; RAMAN; EVOLUTION; GRAPHITE; GRAPHITIZATION; CARBONIZATION; CRYSTALLINITY; DENSIFICATION AB The dimensions of graphitic layer planes directly affect the reactivity of soot towards oxidation and growth. Quantification of graphitic structure could be used to develop and test correlations between the soot nanostructure and its reactivity. Based upon transmission electron microscopy images, this paper provides a demonstration of the robustness of a fringe image analysis code for determining the level of graphitic structure within nanoscale carbon, i.e., soot. Results, in the form of histograms of graphitic layer plane lengths, are compared to their determination through Raman analysis. C1 NASA Glenn, NCMR, Cleveland, OH 44135 USA. RP Vander Wal, RL (reprint author), NASA Glenn, NCMR, 21000 Brookpark Rd,M-S 110-3, Cleveland, OH 44135 USA. EM randy@rvander.grc.nasa.gov NR 49 TC 49 Z9 49 U1 3 U2 16 PU SOC APPLIED SPECTROSCOPY PI FREDERICK PA 201B BROADWAY ST, FREDERICK, MD 21701 USA SN 0003-7028 J9 APPL SPECTROSC JI Appl. Spectrosc. PD FEB PY 2004 VL 58 IS 2 BP 230 EP 237 DI 10.1366/000370204322842986 PG 8 WC Instruments & Instrumentation; Spectroscopy SC Instruments & Instrumentation; Spectroscopy GA 774HW UT WOS:000188974900013 PM 17140483 ER PT J AU Stephens, AW Frogel, JA AF Stephens, AW Frogel, JA TI An infrared spectroscopic study of eight Galactic globular clusters SO ASTRONOMICAL JOURNAL LA English DT Article ID HEAVY-ELEMENT ABUNDANCES; COLOR-MAGNITUDE DIAGRAMS; OMEGA-CENTAURI; METAL-RICH; GIANT BRANCH; RED GIANTS; HIGH-RESOLUTION; METALLICITY SCALE; ARRAY PHOTOMETRY; BULGE AB We have obtained medium-resolution infrared K-band spectra of 44 giants in seven heavily reddened clusters in the Galactic bulge, as well as 12 giants in omega Centauri. We measure the equivalent widths of the Na doublet, the Ca triplet, and the CO band head, and then apply the new technique of Frogel et al. to determine the metallicity of each star. Averaging these values, we estimate the metallicity for each cluster and compare our new [Fe/H] values with previous determinations from the literature. Our estimates for each cluster are NGC 6256 ( - 1.35), NGC 6539 (-0.79), HP 1 (-1.30), Liller 1 (-0.36), Palomar 6 (-0.52), Terzan 2 (-0.87), and Terzan 4 (-1.62). We briefly discuss differences between the various [Fe/H] scales on which it was possible to base our calibration, which is found to be the largest uncertainty in using this technique to determine metallicities. 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. EM stephens@astro.puc.cl NR 52 TC 16 Z9 16 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-6256 J9 ASTRON J JI Astron. J. PD FEB PY 2004 VL 127 IS 2 BP 925 EP 937 DI 10.1086/381294 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 801FG UT WOS:000220081200029 ER PT J AU Rebull, LM Wolff, SC Strom, SE AF Rebull, LM Wolff, SC Strom, SE TI Stellar rotation in young clusters: The first 4 million years SO ASTRONOMICAL JOURNAL LA English DT Review DE stars : rotation ID T-TAURI STARS; PRE-MAIN-SEQUENCE; LOW-MASS STARS; ORION-NEBULA-CLUSTER; ALPHA-PERSEI CLUSTER; ETA-CHAMAELEONTIS CLUSTER; SOLAR-TYPE STARS; X-RAY SOURCES; I DARK CLOUD; ALL-SKY SURVEY AB To investigate what happens to angular momentum during the earliest observable phases of stellar evolution, we searched the literature for periods ( P), projected rotational velocities ( v sin i), and supporting data on K5 - M2 stars ( corresponding to masses 0.25 - 1 M-.) from the Orion Nebula Cluster and environs, rho Ophiuchi, TW Hydra, Taurus-Auriga, NGC 2264, Chamaeleon, Lupus, and eta Chamaeleonis. We combine these measures of rotation with the stellar R (as determined from L-bol and T-eff) to compare the data with two extreme cases: conservation of stellar angular velocity and conservation of stellar angular momentum. Analysis of the P data set suggests that the frequency distribution of periods among the youngest and oldest stars in the sample is indistinguishable, while the v sin i data set reveals a decrease in mean v sin i as a function of age. Both results suggest that a significant fraction of all pre-main-sequence (PMS) stars must evolve at nearly constant angular velocity during the first similar to 3 - 5 Myr after they begin their evolution down the convective tracks. Hence, the angular momenta of a significant fraction of pre - main- sequence ( PMS) stars must be tightly regulated during the first few million years after they first become observable. This result seems surprising at first glance, because observations of young main- sequence stars reveal a population (30% - 40%) of rapidly rotating stars that must begin to spin up at ages tmuch less than5 Myr. To determine whether these apparently contradictory results are reconcilable, we use simple models along with our data set to place limits on ( 1) the fraction of PMS stars that must be regulated, and ( 2) the complementary fraction that could spin up as a function of time but escape statistical detection given the broad distribution of stellar rotation rates. These models include ( 1) instantaneous release at the stellar birthline of a given fraction of stars, with the remaining fraction regulated for 10 Myr; ( 2) all stars regulated initially, with the released fraction varying linearly with time, and timescales for release of half the stars varying from 0.5 to 5 Myr ( i. e., all released by 1 to 10 Myr); and ( 3) a hybrid model that invokes assumptions ( 1) and ( 2). In all cases, we find that a modest population ( 30% - 40%) of PMS stars could be released within the first 1 Myr and still produce period distributions statistically consistent with the observed data. This population is large enough to account for the rapid rotators observed among young main- sequence stars of comparable mass. The limits placed by our models on the fraction of regulated and released stars as a function of time are also consistent with the lifetime of accretion disks as inferred from near-IR excesses, and hence with the hypothesis that disk locking accounts for rotation regulation during early PMS phases. C1 CALTECH, Spitzer Sci Ctr, Pasadena, CA 91125 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Natl Opt Astron Observ, Tucson, AZ 85726 USA. RP Rebull, LM (reprint author), CALTECH, Spitzer Sci Ctr, Mail Stop 220-6,1200 E Calif Blvd, Pasadena, CA 91125 USA. EM luisa.rebull@jpl.nasa.gov OI Rebull, Luisa/0000-0001-6381-515X NR 211 TC 92 Z9 92 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 FEB PY 2004 VL 127 IS 2 BP 1029 EP 1051 DI 10.1086/380931 PG 23 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 801FG UT WOS:000220081200036 ER PT J AU Lynch, DK Wilson, JC Rudy, RJ Venturini, C Mazuk, S Miller, NA AF Lynch, DK Wilson, JC Rudy, RJ Venturini, C Mazuk, S Miller, NA TI Time development of recurrent Nova CI Aquilae's 2000 outburst between 0.8 and 2.5 microns SO ASTRONOMICAL JOURNAL LA English DT Article ID WHITE-DWARF MODELS; IA SUPERNOVAE; INFRARED-SPECTROSCOPY; EMISSION-LINES; EVOLUTION; SAGITTARII; SPECTRUM; CALIBRATION; UNIVERSE; GALAXY AB We report 0.8 - 2.5 mum spectrophotometry of CI Aquilae at eight epochs between 2000 May 9 and 2001 June 2 UT, corresponding to approximately 3 and 391 days after peak brightness. Near peak brightness, the spectra showed emission lines that were characteristic of a low-excitation, nitrogen-rich shell. Within a few weeks, the spectra began to show higher excitation/ionization emission lines indicative of a harder illuminating source: the neutral metal lines faded, leaving only lines of H I, He I, and He II and the emerging coronal lines. A month after peak brightness, the [Ca VIII] coronal line at 2.3205 mum appeared and persisted until the last of our observations, on day + 391. From the O I line ratios, we deduced a reddening of EB - V = 1.5 +/- 0.1 and a visual extinction of A(V) = 4.6 +/- 0.2. Along with the rate of decline from the light curve ( t(2)), we derived a distance of 2.6 +/- 1.3 kpc. The frequently observed unidentified novae lines were present in CI Aquilae along with a potentially new member of the group at 2.425 +/- 0.002 mum. C1 Aerosp Corp, Los Angeles, CA 90009 USA. Cornell Univ, Ithaca, NY 14853 USA. NASA, Goddard Space Flight Ctr, UV Opt Branch, Greenbelt, MD 20771 USA. Univ Calif San Diego, Ctr Astrophys & Space Sci, La Jolla, CA 92093 USA. RP Lynch, DK (reprint author), Aerosp Corp, POB 92957, Los Angeles, CA 90009 USA. EM david.k.lynch@aero.org; jcwbz@virginia.edu; richard.j.rudy@aero.org; nmiller@stis.gsfc.nasa.gov NR 45 TC 18 Z9 18 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 FEB PY 2004 VL 127 IS 2 BP 1089 EP 1097 DI 10.1086/380609 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 801FG UT WOS:000220081200041 ER PT J AU Wilking, BA Meyer, MR Greene, TP Mikhail, A Carlson, G AF Wilking, BA Meyer, MR Greene, TP Mikhail, A Carlson, G TI Low-mass stars and substellar objects in the NGC 1333 molecular cloud SO ASTRONOMICAL JOURNAL LA English DT Article DE infrared : stars; ISM : individual (NGC 1333); stars : low-mass, brown dwarfs; stars : pre-main-sequence ID YOUNG STELLAR OBJECTS; ORION NEBULA CLUSTER; EXTRASOLAR GIANT PLANETS; BROWN DWARF CANDIDATES; NEAR-INFRARED SPECTRA; T-TAURI STARS; MAIN-SEQUENCE; CIRCUMSTELLAR DISKS; FORMING REGION; NGC 1333 AB We present the results of near-infrared imaging and low-resolution near-infrared spectroscopy of low-mass objects in the NGC 1333 molecular cloud. A JHK survey of an 11.'4 x 11.'7 area of the northern cluster was conducted to a sensitivity of K less than or equal to 16 mag. Using near- infrared magnitudes and colors from this and previously published surveys, 25 brown dwarf candidates were selected toward the high-extinction cloud core. Spectra in the K band were obtained and comparisons of the depths of water vapor absorption bands in our candidate objects with a grid of dwarf, subgiant, and giant standards were made to derive spectral types. These data were then used to derive effective temperatures and stellar luminosities that, when combined with theoretical tracks and isochrones for pre - main- sequence objects, resulted in estimates for their masses and ages. The models suggest a median age for the sample of less than 1 Myr with substellar masses for at least nine of the candidates, including the X-ray flare source ASR 24. Surface gravities have been estimated for the brown dwarf candidates and, for a given spectral type, are found to more closely resemble dwarfs than giants. Using the near- infrared imaging data and age estimates from the spectroscopic sample, an extinction-limited sample in the northern cluster was defined. Consistent with recent studies of other young clusters, this sample exhibits an accretion disk frequency of 0.75 +/- 0.20 and a mass spectrum slope across the hydrogen-burning limit of alpha less than or equal to 1.6, where dN/dM proportional to M-alpha. C1 Univ Missouri, Dept Phys & Astron, St Louis, MO 63121 USA. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Wilking, BA (reprint author), Univ Missouri, Dept Phys & Astron, 8001 Nat Bridge Rd, St Louis, MO 63121 USA. EM bwilking@umsl.edu; mmeyer@gould.as.arizona.edu; tgreene@mail.arc.nasa.gov NR 80 TC 52 Z9 52 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 FEB PY 2004 VL 127 IS 2 BP 1131 EP 1146 DI 10.1086/381482 PG 16 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 801FG UT WOS:000220081200044 ER PT J AU Moehler, S Sweigart, AV Landsman, WB Hammer, NJ Dreizler, S AF Moehler, S Sweigart, AV Landsman, WB Hammer, NJ Dreizler, S TI Spectroscopic analyses of the blue hook stars in NGC 2808: A more stringent 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 2808 Galaxy : globular clusters : individual : NGC 5139 ID GLOBULAR-CLUSTER NGC-2808; SUBDWARF B-STARS; HORIZONTAL-BRANCH; PHYSICAL PARAMETERS; HB-STARS; MASS-DISTRIBUTION; OMEGA-CENTAURI; WHITE-DWARFS; CONSEQUENCES; PHOTOMETRY AB Recent UV observations of the globular cluster NGC 2808 (Brown et al. 2001) show a significant population of hot stars fainter than the zero-age horizontal branch ("blue hook" stars), which cannot be explained by canonical stellar evolution. Their results suggest that stars which experience unusually large mass loss on the red giant branch and which subsequently undergo 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 horizontal branch stars and should have helium- and carbon-rich atmospheres. As a test of this late hot flasher scenario, we have obtained and analysed medium resolution spectra of a sample of blue hook stars in NGC 2808 to derive their atmospheric parameters. Using the same procedures, we have also re-analyzed our earlier spectra of the blue hook stars in omega Cen (Moehler et al. 2002) for comparison with the present results for NGC 2808. The blue hook stars in these two clusters are both hotter (T-eff greater than or equal to 35 000 K) and more helium-rich than canonical extreme horizontal branch stars in agreement with the late hot flasher scenario. Moreover, we find indications for carbon enhancement in the three most helium-enriched stars in NGC 2808. However, the blue hook stars still show some hydrogen in their atmospheres, perhaps indicating that some residual hydrogen survives a late hot flash and then later diffuses to the surface during the horizontal branch phase. We note that the presence of blue hook stars apparently depends mostly on the total mass of the globular cluster and not so much on its horizontal branch morphology. C1 Univ Kiel, Inst Theoret Phys & Astrophys, Abt Astrophys, D-24098 Kiel, Germany. NASA, SSAI, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Tubingen, Inst Astron & Astrophys, D-72076 Tubingen, Germany. Univ Sternwarte Gottingen, D-37083 Gottingen, Germany. RP Moehler, S (reprint author), Univ Kiel, Inst Theoret Phys & Astrophys, Abt Astrophys, Olshaussenstr 40, D-24098 Kiel, Germany. EM moehler@astrophysik.uni-kiel.de; Allen.V.Sweigart@nasa.gov; landsman@mpb.gsfc.nasa.gov; hammer@astro.uni-tuebingen.de; dreizler@astro.physik.uni-goettinen.de OI Moehler, Sabine/0000-0002-4152-9643 NR 37 TC 60 Z9 60 U1 0 U2 0 PU E D P SCIENCES PI LES ULIS CEDEXA PA 7, AVE DU HOGGAR, PARC D ACTIVITES COURTABOEUF, BP 112, F-91944 LES ULIS CEDEXA, FRANCE SN 0004-6361 J9 ASTRON ASTROPHYS JI Astron. Astrophys. PD FEB PY 2004 VL 415 IS 1 BP 313 EP 323 DI 10.1051/0004-6361:20034505 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 770JY UT WOS:000188720500032 ER PT J AU van Broekhuizen, FA Keane, JV Schutte, WA AF van Broekhuizen, FA Keane, JV Schutte, WA TI A quantitative analysis of OCN- formation in interstellar ice analogs SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE methods : laboratory; ISM : molecules; ISM : lines and bands ID YOUNG STELLAR OBJECTS; TIME-DEPENDENT CHEMISTRY; DENSE MOLECULAR CLOUDS; SOLID CARBON-DIOXIDE; 3 MICRON SPECTRA; T-TAURI STARS; LINE-OF-SIGHT; ABSORPTION FEATURES; GRAIN MANTLES; INFRARED-SPECTROSCOPY AB The 4.62 mum absorption band, observed along the line-of-sight towards various young stellar objects, is generally used as a qualitative indicator for energetic processing of interstellar ice mantles. This interpretation is based on the excellent fit with OCN-, which is readily formed by ultraviolet (UV) or ion-irradiation of ices containing H2O, CO and NH3. However, the assignment requires both qualitative and quantitative agreement in terms of the efficiency of formation as well as the formation of additional products. Here. we present the first quantitative results on the efficiency of laboratory formation of OCN- from ices composed of different combinations of H2O, CO, CH3OH, HNCO and NH3 by UV- and thermally-mediated solid state chemistry. Our results show large implications for the use of the 4.62 mum feature as a diagnostic for energetic ice-processing. UV-mediated formation of OCN- from H2O/CO/NH3 ice matrices falls short in reproducing the highest observed interstellar abundances. In this case, at most 2.7% OCN- is formed with respect to H2O under conditions that no longer apply to a molecular cloud environment. On the other hand, photoprocessing and in particular thermal processing of solid HNCO in the presence of NH3 are very efficient OCN- formation mechanisms, converting 60%-85% and similar to100%, respectively of the original HNCO. We propose that OCN- is most likely formed thermally from HNCO given the ease and efficiency of this mechanism. Upper limits on solid HNCO and the inferred interstellar ice temperatures are in agreement with this scenario. C1 Leiden Observ, Raymond & Beverly Sackler Lab Astrophys, NL-2300 RA Leiden, Netherlands. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP van Broekhuizen, FA (reprint author), Leiden Observ, Raymond & Beverly Sackler Lab Astrophys, POB 9513, NL-2300 RA Leiden, Netherlands. EM fvb@strw.leidenuniv.nl NR 75 TC 64 Z9 64 U1 0 U2 4 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 FEB PY 2004 VL 415 IS 2 BP 425 EP 436 DI 10.1051/0004-6361:20034161 PG 12 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 773RG UT WOS:000188936100009 ER PT J AU Weis, K Corcoran, MF Bomans, DJ Davidson, K AF Weis, K Corcoran, MF Bomans, DJ Davidson, K TI A spectral and spatial analysis of eta Carinae's diffuse X-ray emission using CHANDRA SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE stars : evolution; stars : individual : eta Carinae; stars : mass-loss; ISM : bubbles; ISM : jets and outflows ID LUMINOUS BLUE VARIABLES; MASSIVE STARS; OUTER SHELL; NEBULA; EVOLUTION; SPECTROSCOPY; VARIABILITY; MOTIONS; BINARY; GAS AB The luminous unstable star (star system) eta Carinae is surrounded by an optically bright bipolar nebula, the Homunculus and a fainter but much larger nebula, the so-called outer ejecta. As images from the EINSTEIN and ROSAT satellites have shown. the outer ejecta is also visible in soft X-rays, while the central source is present in the harder X-ray bands. With our CHANDRA observations we show that the morphology and properties of the X-ray nebula are the result of shocks from fast clumps in the outer ejecta moving into a pre-existing denser circumstellar medium. An additional contribution to the soft X-ray flux results from mutual interactions of clumps within the ejecta. Spectra extracted from the CHANDRA data yield gas temperatures kT of 0.6-0.76 keV. The implied pre-shock velocities of 670-760 km s(-1) are within the scatter of the velocities we measure for the majority of the clumps in the corresponding regions. Significant nitrogen enhancements over solar abundances are needed for acceptable fits in all parts of the outer ejecta, consistent with CNO processed material and non-uniform enhancement. The presence of a diffuse spot of hard X-ray emission at the S condensation shows some contribution of the highest velocity clumps and further underlines the multicomponent, non-equilibrium nature of the X-ray nebula. The detection of an X-ray "bridge" between the northern and southern part of the X-ray nebula and an X-ray shadow at the position of the NN bow can be attributed to a large expanding disk, which would appear as an extension of the equatorial disk. No soft emission is seen from the Homunculus, or from the NN bow or the "strings". C1 Ruhr Univ Bochum, Astron Inst, D-44780 Bochum, Germany. Univ Minnesota, Dept Astron, Minneapolis, MN 55455 USA. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. Univ Space Res Assoc, Seabrook, MD 20706 USA. RP Weis, K (reprint author), Ruhr Univ Bochum, Astron Inst, Univ Str 150, D-44780 Bochum, Germany. EM kweis@astro.rub.de NR 52 TC 15 Z9 15 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 FEB PY 2004 VL 415 IS 2 BP 595 EP 607 DI 10.1051/0004-6361:20034306 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 773RG UT WOS:000188936100025 ER PT J AU Cassam-Chenai, G Decourchelle, A Ballet, J Hwang, U Hughes, JP Petre, R AF Cassam-Chenai, G Decourchelle, A Ballet, J Hwang, U Hughes, JP Petre, R TI XMM-Newton observation of Kepler's supernova remnant SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE ISM : supernova remnants; ISM : individual objects : Kepler, SN1604; X-rays : ISM ID X-RAY-SPECTRUM; CASSIOPEIA-A; NOVA REMNANT; EMISSION; SHOCK; TYCHO; ACCELERATION; SPECTROSCOPY; CHANDRA; EJECTA AB We present the first results coming from the observation of Kepler's supernova remnant obtained with the EPIC instruments on board the XMM-Newton satellite. We focus on the images and radial profiles of the emission lines ( Si K, Fe L, Fe K) and of the high energy continuum. Chiefly, the Fe L and Si K emission-line images are generally consistent with each other and the radial profiles show that the Si K emission extends to a larger radius than the Fe L emission ( distinctly in the southern part of the remnant). Therefore, in contrast to Cas A, no inversion of the Si- and Fe-rich ejecta layers is observed in Kepler. Moreover, the Fe K emission peaks at a smaller radius than the Fe L emission, which implies that the temperature increases inwards in the ejecta. The 4 - 6 keV high energy continuum map shows the same distribution as the asymmetric emission-line images except in the southeast where there is a strong additional emission. A two color image of the 4 - 6 keV and 8 - 10 keV high energy continuum illustrates that the hardness variations of the continuum are weak all along the remnant except in a few knots. The asymmetry in the Fe K emission-line is not associated with any asymmetry in the Fe K equivalent width map. The Si K maps lead to the same conclusions. Hence, abundance variations do not cause the north-south brightness asymmetry. The strong emission in the north may be due to overdensities in the circumstellar medium. In the southeastern region of the remnant, the lines have a very low equivalent width and the X-ray emission is largely nonthermal. C1 CEA Saclay, Serv Astrophys, F-91191 Gif Sur Yvette, France. Univ Maryland, Dept Astron, College Pk, MD 20742 USA. Rutgers State Univ, Dept Phys & Astron, Piscataway, NJ 08854 USA. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Cassam-Chenai, G (reprint author), CEA Saclay, Serv Astrophys, F-91191 Gif Sur Yvette, France. EM gcc@discovery.saclay.cea.fr NR 52 TC 59 Z9 60 U1 1 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 FEB PY 2004 VL 414 IS 2 BP 545 EP 558 DI 10.1051/0004-6361:20031551 PG 14 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 765CH UT WOS:000188249200018 ER PT J AU Van Malderen, R Decin, L Kester, D Vandenbussche, B Waelkens, C Cami, J Shipman, RF AF Van Malderen, R Decin, L Kester, D Vandenbussche, B Waelkens, C Cami, J Shipman, RF TI On the analysis of band 3 of the ISO-SWS calibration sources SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE stars : atmospheres; stars : fundamental parameters; instrumentation : spectrographs; molecular data ID DIPOLE-MOMENT FUNCTION; COOL-STAR ATMOSPHERES; LINE-DATA-BASE; SPECTRAL IRRADIANCE CALIBRATION; WATER-VAPOR; STELLAR ATMOSPHERES; MODEL ATMOSPHERES; ROTATION LINES; GIANT STARS; SOLAR AB We analyse ISO - SWS 01 (R similar to 1500) 12- 27.5 mum (band 3) spectra of the 10 standard calibration stars with the highest flux using synthetic spectra generated from (MARCS) atmosphere models. The comparison between the observed and synthetic spectra reveals the quality of ( 1) the atmospheric model construction and subsequent synthetic spectra computation and of ( 2) the (OLP 10.1) calibration and data reduction of the spectrometer at these wavelengths. The models represent the general features of the observations, but the synthetic spectrum computation is hampered by the lack of comprehensive molecular and atomic line lists. We also suspect some problems with the temperature distribution in the outer layers of the model and inaccuracies in the extrapolation of the collision-induced absorption coefficients of H-2 pairs. We detect baseline ripples and fringes in the observed spectra, that survive the calibration and detailed reduction process. Photometric calibration uncertainties are estimated by means of the scaling factors between the synthetic and observed spectra. C1 Katholieke Univ Leuven, Inst Sterrenkunde, B-3001 Heverlee, Belgium. Space Res Org Netherlands, NL-9700 AV Groningen, Netherlands. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Van Malderen, R (reprint author), Katholieke Univ Leuven, Inst Sterrenkunde, Celestijnenlaan 200B, B-3001 Heverlee, Belgium. EM Roeland.VanMalderen@ster.kuleuven.ac.be NR 64 TC 10 Z9 10 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 FEB PY 2004 VL 414 IS 2 BP 677 EP 697 DI 10.1051/0004-6361:20031579 PG 21 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 765CH UT WOS:000188249200029 ER PT J AU Kley, W Peitz, J Bryden, G AF Kley, W Peitz, J Bryden, G TI Evolution of planetary systems in resonance SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE accretion, accretion disks; planets and satellites : formation; hydrodynamics; celestial mechanics ID MEAN-MOTION RESONANCE; EXTRASOLAR PLANETS; PROTOSTELLAR DISKS; ORBITAL MIGRATION; MASS PLANETS; PROTOPLANETS; ACCRETION; GJ-876; DISCS; SIMULATIONS AB We study the time evolution of two protoplanets still embedded in a protoplanetary disk. The results of two different numerical approaches are presented and compared. In the first approach, the motion of the disk material is computed with viscous hydrodynamical simulations, and the planetary motion is determined by N-body calculations including exactly the gravitational forces exerted by the disk material. In the second approach, only the N-body integration is performed but with additional dissipative forces included such as to mimic the effect of the disk torques acting on the disk. This type of modeling is much faster than the full hydrodynamical simulations, and gives comparative results provided that parameters are adjusted properly. Resonant capture of the planets is seen in both approaches, where the order of the resonance depends on the properties of the disk and the planets. Resonant capture leads to a rise in the eccentricity and to an alignment of the spatial orientation of orbits. The numerical results are compared with the observed planetary systems in mean motion resonance (GJ 876, HD 82943, and 55 Cnc). We find that the forcing together of two planets by their parent disk produces resonant configurations similar to those observed, but that eccentricity damping greater than that obtained in our hydrodynamic simulations is required to match the GJ 876 observations. C1 Univ Tubingen, Inst Astron & Astrophys, Abt Computat Phys, D-72076 Tubingen, Germany. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Kley, W (reprint author), Univ Tubingen, Inst Astron & Astrophys, Abt Computat Phys, Morgenstelle 10, D-72076 Tubingen, Germany. EM kley@tat.physik.uni-tuebingen.de RI Kley, Wilhelm/A-4921-2012 NR 37 TC 91 Z9 91 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 FEB PY 2004 VL 414 IS 2 BP 735 EP 747 DI 10.1051/0004-6361:20031589 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 765CH UT WOS:000188249200034 ER PT J AU Spoon, HWW Moorwood, AFM Lutz, D Tielens, AGGM Siebenmorgen, R Keane, JV AF Spoon, HWW Moorwood, AFM Lutz, D Tielens, AGGM Siebenmorgen, R Keane, JV TI Mid-infrared spectral evidence for a luminous dust enshrouded source in Arp 220 SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE galaxies : individual : Arp220; galaxies : ISM; galaxies : nuclei; galaxies : starburst; infrared : galaxies ID ULTRALUMINOUS INFRARED GALAXIES; ARP 220; INTERSTELLAR EXTINCTION; STAR-FORMATION; ISO SPECTROSCOPY; GALACTIC NUCLEI; RADIO-CONTINUUM; IRAS GALAXIES; COLD DUST; NGC 4945 AB We have re-analyzed the 6-12 mum ISO spectrum of the ultra-luminous infrared galaxy Arp 220 with the conclusion that it is not consistent with that of a scaled up version of a typical starburst. Instead, both template fitting with spectra of the galaxies NGC 4418 and M 83 and with dust models suggest that it is best represented by combinations of a typical starburst component, exhibiting PAH emission features, and a heavily absorbed dust continuum which contributes similar to40% of the 6-12 mum flux and likely dominates the luminosity. Of particular significance relative to previous studies of Arp 220 is the fact that the emission feature at 7.7 mum comprises both PAH emission and a broader component resulting from ice and silicate absorption against a heavily absorbed continuum. Extinction to the PAH emitting source, however, appears to be relatively low. We tentatively associate the PAH emitting and heavily dust/ice absorbed components with the diffuse emission region and the two compact nuclei respectively identified by Soifer et al. (2002) in their higher spatial resolution 10 mum study. Both the similarity of the absorbed continuum with that of the embedded Galactic protostars and results of the dust models imply that the embedded source(s) in Arp 220 could be powered by, albeit extremely dense, starburst activity. Due to the high extinction, it is not possible with the available data to exclude that AGN(s) also contribute some or all of the observed luminosity. In this case, however, the upper limit measured for its hard X-ray emission would require Arp 220 to be the most highly obscured AGN known. C1 Univ Groningen, Kapteyn Inst, NL-9700 AV Groningen, Netherlands. European So Observ, D-85748 Garching, Germany. Max Planck Inst Extraterr Phys MPE, D-85741 Garching, Germany. Univ Groningen, SRON, NL-9700 AV Groningen, Netherlands. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Spoon, HWW (reprint author), Univ Groningen, Kapteyn Inst, POB 800, NL-9700 AV Groningen, Netherlands. EM spoon@isc.astro.cornell.edu NR 70 TC 54 Z9 54 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 FEB PY 2004 VL 414 IS 3 BP 873 EP 883 DI 10.1051/0004-6361:20031656 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 780JH UT WOS:000189377200014 ER PT J AU Sambruna, RM Gliozzi, M Donato, D Tavecchio, F Cheung, CC Mushotzky, RF AF Sambruna, RM Gliozzi, M Donato, D Tavecchio, F Cheung, CC Mushotzky, RF TI The XMM-Newton view of the X-ray halo and jet of NGC 6251 SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE galaxies : active; galaxies : nuclei; X-rays : galaxies ID ACTIVE GALACTIC NUCLEI; EARLY-TYPE GALAXIES; RADIO GALAXY; MAGNETIC-FIELD; BLACK-HOLES; NGC 6251; EMISSION; CHANDRA AB We present an XMM-Newton observation of the radio jet and diffuse halo of the nearby radio galaxy NGC 6251. The EPIC spectrum of the galaxy's halo is best-fitted by a thermal model with temperature kT similar to 1.6 keV and sub-solar abundances. Interestingly, an additional hard X-ray component is required to fit the EPIC spectra of the halo above 3 keV, and is independently confirmed by an archival Chandra observation. However, its physical origin is not clear. Contribution from a population of undetected Low Mass X-ray Binaries seems unlikely. Instead, the hard X-ray component could be due to inverse Compton scattering of the CMB photons (IC/CMB) off relativistic electrons scattered throughout the halo of the galaxy, or non-thermal bremsstrahlung emission. The IC/CMB interpretation, together with limits on the diffuse radio emission, implies a very weak magnetic field, B << 1 muGauss, while a non-thermal bremsstrahlung origin implies the presence of a large number of very energetic electrons. We also detect X-ray emission from the outer (similar to3.5') jet, confirming previous ROSAT findings. Both the EPIC and ACIS spectra of the jet are best-fitted by a power law with photon index Gamma similar to 1.2, fixed Galactic column density, and 1 keV flux F-1 kev = 2.1 nJy. A thermal model is formally ruled out by the data. Assuming an origin of the X-rays from the jet via IC/CMB, as suggested by energetic arguments, and assuming equipartition implies a large Doppler factor (delta similar to 10). Alternatively, weaker beaming is possible for magnetic fields several orders of magnitude lower than the equipartition field. C1 George Mason Univ, Dept Phys & Astron, Fairfax, VA 22030 USA. George Mason Univ, Sch Computat Sci, Fairfax, VA 22030 USA. Osserv Astron Brera, I-20121 Milan, Italy. Brandeis Univ, Dept Phys, Waltham, MA 02454 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Sambruna, RM (reprint author), George Mason Univ, Dept Phys & Astron, MS 3F3,4400 Univ Dr, Fairfax, VA 22030 USA. EM rms@physics.gmu.edu NR 40 TC 20 Z9 20 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 FEB PY 2004 VL 414 IS 3 BP 885 EP 894 DI 10.1051/0004-6361:20031657 PG 10 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 780JH UT WOS:000189377200015 ER PT J AU Vokrouhlicky, D Capek, D Kaasalainen, M Ostro, SJ AF Vokrouhlicky, D Capek, D Kaasalainen, M Ostro, SJ TI Detectability of YORP rotational slowing of asteroid 25143 Itokawa SO ASTRONOMY & ASTROPHYSICS LA English DT Article DE solar system : minor planets, asteroids; radiations mechanisms : thermal ID C MISSION TARGET; 25143 1998 SF36; MUSES-C; CCD PHOTOMETRY AB We predict that the YORP thermal-emission effect can be directly detected through a measurable increase in the rotation period of the several-hundred-meter near-Earth asteroid 25143 Itokawa. The fractional change of Itokawa's rotation rate in between 2001 and 2004 should be (1-2) x 10(-4), significantly larger than its currently estimated uncertainty similar or equal to 5 x 10(-5). The corresponding change of sidereal rotation phase, normalized to unity in a cycle, is similar or equal to (0.09-0.25) in January 2004, producing similar or equal to(1-3) h delay of lightcurve maximum. C1 Charles Univ, Inst Astron, Prague 18000 8, Czech Republic. Univ Helsinki, Rolf Nevanlinna Inst, Helsinki 00014, Finland. Univ Oulu, Sodankyla Geophys Observ, Sodankyla 99600, Finland. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Vokrouhlicky, D (reprint author), Charles Univ, Inst Astron, V Holesovickach 2, Prague 18000 8, Czech Republic. EM vokrouhl@mbox.cesnet.cz; capek@sirrah.troja.mff.cuni.cz; mjk@rni.helsinki.fi; ostro@reason.jpl.nasa.gov RI Capek, David/G-9005-2014; Kaasalainen, Mikko/G-4236-2014 NR 12 TC 14 Z9 14 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 FEB PY 2004 VL 414 IS 2 BP L21 EP L24 DI 10.1051/0004-6361:20031739 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 765CH UT WOS:000188249200003 ER PT J AU Robinson, K Dursi, LJ Ricker, PM Rosner, R Calder, AC Zingale, M Truran, JW Linde, T Caceres, A Fryxell, B Olson, K Riley, K Siegel, A Vladimirova, N AF Robinson, K Dursi, LJ Ricker, PM Rosner, R Calder, AC Zingale, M Truran, JW Linde, T Caceres, A Fryxell, B Olson, K Riley, K Siegel, A Vladimirova, N TI Morphology of rising hydrodynamic and magnetohydrodynamic bubbles from numerical simulations SO ASTROPHYSICAL JOURNAL LA English DT Article DE cooling flows; galaxies : clusters : general; hydrodynamics; instabilities; MHD; X-rays : galaxies : clusters ID PIECEWISE-PARABOLIC METHOD; COOLING-FLOW CLUSTERS; BUOYANT RADIO PLASMA; X-RAY OBSERVATIONS; INTRACLUSTER MEDIUM; XMM-NEWTON; CHANDRA OBSERVATIONS; HOT BUBBLES; GALAXIES; GAS AB Recent Chandra and XMM-Newton observations of galaxy cluster cooling flows have revealed X-ray emission voids of up to 30 kpc in size that have been identified with buoyant, magnetized bubbles. Motivated by these observations, we have investigated the behavior of rising bubbles in stratified atmospheres using the FLASH(9) adaptive-mesh simulation code. We present results from two-dimensional simulations with and without the effects of magnetic fields and with varying bubble sizes and background stratifications. We find purely hydrodynamic bubbles to be unstable; a dynamically important magnetic field is required to maintain a bubble's integrity. This suggests that, even absent thermal conduction, for bubbles to be persistent enough to be regularly observed, they must be supported in large part by magnetic fields. Thermal conduction unmitigated by magnetic fields can dissipate the bubbles even faster. We also observe that the bubbles leave a tail as they rise; the structure of these tails can indicate the history of the dynamics of the rising bubble. C1 Lawrence Univ, Dept Phys, Appleton, WI 54912 USA. Univ Chicago, Ctr Astrophys Thermonucl Flashes, Chicago, IL 60637 USA. Univ Chicago, Dept Astron & Astrophys, Chicago, IL 60637 USA. Univ Illinois, Dept Astron, Urbana, IL 61801 USA. Univ Illinois, Dept Astron, Urbana, IL 61801 USA. Natl Ctr Supercomp Applicat, Urbana, IL 61801 USA. Univ Chicago, Dept Phys, Chicago, IL 60637 USA. Univ Calif Santa Cruz, Dept Astron & Astrophys, Santa Cruz, CA 95064 USA. Univ Maryland Baltimore Cty, NASA, Goddard Space Flight Ctr, Goddard Earth Sci & Technol Ctr, Greenbelt, MD 20771 USA. RP Robinson, K (reprint author), Lawrence Univ, Dept Phys, Appleton, WI 54912 USA. RI Calder, Alan/E-5348-2011; OI Zingale, Michael/0000-0001-8401-030X; Dursi, Jonathan/0000-0002-4697-798X NR 45 TC 67 Z9 70 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 FEB 1 PY 2004 VL 601 IS 2 BP 621 EP 643 DI 10.1086/380817 PN 1 PG 23 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 769PC UT WOS:000188658100003 ER PT J AU Mattson, BJ Weaver, KA AF Mattson, BJ Weaver, KA TI RXTE and BeppoSAX observations of MCG-5-23-16: Reflection from distant cold material SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : individual (MCG-5-23-16); galaxies : Seyfert; X-rays : galaxies ID X-RAY-SPECTRA; ACTIVE GALACTIC NUCLEI; SEYFERT-GALAXIES; COMPTON REFLECTION; IRON LINE; OBSCURING TORUS; VARIABILITY; EMISSION; MATTER AB We examine the spectral variability of the Seyfert 1.9 galaxy MCG-5-23-16 by using the Rossi X-Ray Timing Explorer (RXTE) and BeppoSAX observations spanning 2 years from 1996 April to 1998 April. During the first year the X-ray source brightens by a factor of similar to25% on timescales of days to months. During this time, the reprocessed continuum emission seen with RXTE does not respond measurably to the continuum increase. However, by the end of the second year during the BeppoSAX epoch the X-ray source has faded again. This time, the reprocessed emission has also faded, indicating that the reprocessed flux has responded to the continuum. If these effects are caused by time delays due to the distance between the X-ray source and the reprocessing region, we derive a light crossing time between similar to1 lt-day and similar to1.5 lt-yr. This corresponds to a distance of 0.001 to 0.55 pc, which implies that the reprocessed emission originates between 3x10(15) and 1.6x10(18) cm from the X-ray source. In other words, the reprocessing in MCG-5-23-16 is not dominated by the inner regions of a standard accretion disk. C1 NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Mattson, BJ (reprint author), NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. NR 31 TC 14 Z9 14 U1 0 U2 1 PU UNIV CHICAGO PRESS PI CHICAGO PA 1427 E 60TH ST, CHICAGO, IL 60637-2954 USA SN 0004-637X J9 ASTROPHYS J JI Astrophys. J. PD FEB 1 PY 2004 VL 601 IS 2 BP 771 EP 777 DI 10.1086/380502 PN 1 PG 7 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 769PC UT WOS:000188658100013 ER PT J AU Dale, DA Roussel, H Contursi, A Helou, G Dinerstein, HL Hunter, DA Hollenbach, DJ Egami, E Matthews, K Murphy, TW Lafon, CE Rubin, RH AF Dale, DA Roussel, H Contursi, A Helou, G Dinerstein, HL Hunter, DA Hollenbach, DJ Egami, E Matthews, K Murphy, TW Lafon, CE Rubin, RH TI Near-infrared integral field spectroscopy of star-forming galaxies SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : ISM; HII regions; infrared : galaxies; stars : formation ID SPECTRAL ENERGY-DISTRIBUTIONS; BLUE COMPACT GALAXIES; EMISSION-LINE SPECTRA; H-II REGIONS; INTERSTELLAR-MEDIUM; SPIRAL GALAXIES; FE-II; PHYSICAL CONDITIONS; STARBURST GALAXIES; ORION NEBULA AB The Palomar Integral Field Spectrograph was used to probe a variety of environments in nine nearby galaxies that span a range of morphological types, luminosities, metallicities, and infrared-to-blue ratios. For the first time, near-infrared spectroscopy was obtained for nuclear or bright H II regions in star-forming galaxies over two spatial dimensions (5."7x10."0) in the [Fe II] (1.257 mum), [Fe II] (1.644 mum), Pabeta (1.282 mum), H-2 (2.122 mum), and Brgamma (2.166 mum) transition lines. These data yield constraints on various characteristics of the star-forming episodes in these regions, including their strength, maturity, spatial variability, and extinction. The H II regions stand out from the nuclei. Unlike observations of nuclear regions, H II region near-infrared observations do not show a spatial coincidence of the line and continuum emission; the continuum and line maps of H II regions usually show distinct and sometimes spatially separated morphologies. Gauging from Pabeta and Brgamma equivalent widths and luminosities, the H II regions have younger episodes of star formation than the nuclei and more intense radiation fields. Near-infrared line ratio diagnostics suggest that H II regions have "purer'' starbursting properties. The correlation between ionizing photon density and mid-infrared color is consistent with the star formation activity level being higher for H II regions than for nuclei. And though the interpretation is complicated, on a purely empirical basis the H II regions show lower Fe1+ abundances than nuclei by an order of magnitude. C1 Univ Wyoming, Dept Phys & Astron, Laramie, WY 82071 USA. CALTECH, Pasadena, CA 91125 USA. Max Planck Inst Extraterr Phys, D-85748 Garching, Germany. Ctr Infrared Proc & Anal, Pasadena, CA 91125 USA. Univ Texas, Dept Astron, Austin, TX 78712 USA. Lowell Observ, Flagstaff, AZ 86001 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. Univ Washington, Dept Phys, Seattle, WA 98195 USA. Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA. RP Dale, DA (reprint author), Univ Wyoming, Dept Phys & Astron, Laramie, WY 82071 USA. EM ddale@uwyo.edu NR 84 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 FEB 1 PY 2004 VL 601 IS 2 BP 813 EP 830 DI 10.1086/380753 PN 1 PG 18 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 769PC UT WOS:000188658100017 ER PT J AU Weisskopf, MC O'Dell, SL Paerels, F Elsner, RF Becker, W Tennant, AF Swartz, DA AF Weisskopf, MC O'Dell, SL Paerels, F Elsner, RF Becker, W Tennant, AF Swartz, DA TI Chandra phase-resolved X-ray spectroscopy of the Crab pulsar SO ASTROPHYSICAL JOURNAL LA English DT Article DE atomic processes; ISM : general; pulsars : individual (Crab Pulsar); stars : neutron; techniques : spectroscopic; X-rays : stars ID PHOTOIONIZATION CROSS-SECTIONS; INTERSTELLAR-MEDIUM; NEUTRON-STARS; ANALYTIC FITS; ABUNDANCE; SCATTERING; ABSORPTION; EMISSION; NEBULA; OXYGEN AB We present the first phase-resolved study of the X-ray spectral properties of the Crab pulsar that covers all pulse phases. The superb angular resolution of the Chandra X-Ray Observatory enables distinguishing the pulsar from the surrounding nebulosity, even at pulse minimum. Analysis of the pulse-averaged spectrum measures interstellar X-ray extinction due primarily to photoelectric absorption and secondarily to scattering by dust grains in the direction of the Crab Nebula. We confirm previous findings that the line of sight to the Crab is under-abundant in oxygen, although more so than recently measured. Using recent abundances and cross sections from Wilms, Allen, and McCray, we find [O/H] = (3.33 +/- 0.25) x 10(-4). Analysis of the spectrum as a function of pulse phase measures the low-energy X-ray spectral index even at pulse minimum - albeit with large statistical uncertainty - and we find marginal evidence for variations of the spectral index. The data are also used to set a new (3 sigma) upper limit to the temperature of the neutron star of log T-infinity < 6.30. C1 NASA, Dept Space Sci, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. Columbia Univ, Columbia Astrophys Lab, New York, NY 10027 USA. Columbia Univ, Dept Phys, New York, NY 10027 USA. Max Planck Inst Extraterr Phys, D-85740 Garching, Germany. NASA, Univ Space Res Assoc, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Weisskopf, MC (reprint author), NASA, Dept Space Sci, George C Marshall Space Flight Ctr, SD50, Huntsville, AL 35812 USA. OI O'Dell, Stephen/0000-0002-1868-8056 NR 40 TC 54 Z9 54 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 FEB 1 PY 2004 VL 601 IS 2 BP 1050 EP 1057 DI 10.1086/380600 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 769PC UT WOS:000188658100036 ER PT J AU Atrio-Barandela, F Kashlinsky, A Mucket, JP AF Atrio-Barandela, F Kashlinsky, A Mucket, JP TI Measuring the Mach number of the universe via the Sunyaev-Zeldovich effect SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmic microwave background; cosmology : observations; cosmology : theory ID PECULIAR VELOCITY-FIELDS; PROBE WMAP OBSERVATIONS; GALAXY CLUSTERS; BULK FLOWS; ANISOTROPIES; SIMULATIONS; COSMOLOGY; SPECTRUM; CONSTANT; LIMITS AB We introduce a new statistic to measure more accurately the cosmic sound speed of clusters of galaxies at different redshifts. This statistic is evaluated by cross-correlating cosmic microwave background (CMB) fluctuations caused by the Sunyaev-Zeldovich effect from observed clusters of galaxies with their redshifts. When clusters are distributed in redshift bins of narrow width, one could measure the mean squared cluster peculiar velocity with an error sigma(cs)(2) less than or similar to (300 km s(-1))(2). This can be done around z > 0.3 with clusters of flux above 200 mJy, which will be detected Planck, coupled with high- resolution microwave images to eliminate the cosmological part of the CMB fluctuations. The latter can be achieved with observations by the planned Atacama Large Millimeter Array or the NSF South Pole telescope and other surveys. By measuring the cosmic sound speed and the bulk flow in, for example, four spheres of similar to100 h(-1) Mpc at z = 0.3, we could have a direct measurement of the matter density 0.21 < &UOmega;(m) < 0.47 at the 95% confidence level. C1 Univ Salamanca, E-37008 Salamanca, Spain. NASA, Goddard Space Flight Ctr, SSAI, Greenbelt, MD 20771 USA. Astrophys Inst Potsdam, D-14482 Potsdam, Germany. RP Atrio-Barandela, F (reprint author), Univ Salamanca, Plaza Merced S-N, E-37008 Salamanca, Spain. EM atrio@usal.es; kashlinsky@stgars.gsfc.nasa.gov; jpmuecket@aip.de RI Atrio-Barandela, Fernando/A-7379-2017 OI Atrio-Barandela, Fernando/0000-0002-2130-2513 NR 33 TC 12 Z9 12 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 FEB 1 PY 2004 VL 601 IS 2 BP L111 EP L114 DI 10.1086/382154 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 769PE UT WOS:000188658300001 ER PT J AU Sembach, KR Wakker, BP Tripp, TM Richter, P Kruk, JW Blair, WP Moos, HW Savage, BD Shull, JM York, DG Sonneborn, G Hebrard, G Ferlet, R Vidal-Madjar, A Friedman, SD Jenkins, EB AF Sembach, KR Wakker, BP Tripp, TM Richter, P Kruk, JW Blair, WP Moos, HW Savage, BD Shull, JM York, DG Sonneborn, G Hebrard, G Ferlet, R Vidal-Madjar, A Friedman, SD Jenkins, EB TI The deuterium-to-hydrogen ratio in a low-metallicity cloud falling onto the Milky Way SO ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES LA English DT Review DE cosmology : observations; Galaxy : evolution; ISM : abundances; ISM : clouds; nuclear reactions, nucleosynthesis, abundances; quasars : individual (PG 1259+593) ID ULTRAVIOLET-SPECTROSCOPIC-EXPLORER; HIGH-VELOCITY CLOUDS; TELESCOPE IMAGING SPECTROGRAPH; ABSORPTION PROFILE SPECTROGRAPH; INTERSTELLAR ATOMIC DEUTERIUM; GALACTIC CHEMICAL EVOLUTION; ON-ORBIT PERFORMANCE; FUSE MISSION; MOLECULAR-HYDROGEN; COMPLEX-C AB Using Far Ultraviolet Spectroscopic Explorer (FUSE) and Hubble Space Telescope observations of the QSO PG 1259+593, we detect D I Lyman series absorption in high-velocity cloud Complex C, a low-metallicity gas cloud falling onto the Milky Way. This is the first detection of atomic deuterium in the local universe in a location other than the nearby regions of the Galactic disk. We construct a velocity model for the sight line based on the numerous O I absorption lines detected in the ultraviolet spectra. We identify eight absorption-line components, two of which are associated with the high-velocity gas in Complex C at approximate to-128 and approximate to-112 km s(-1). A new Westerbork Synthesis Radio Telescope (WSRT) interferometer map of the H I 21 cm emission toward PG 1259+593 indicates that the sight line passes through a compact concentration of neutral gas in Complex C. We use the WSRT data together with single-dish data from the Effelsberg 100 m radio telescope to estimate the H I column density of the high-velocity gas and to constrain the velocity extents of the H I Lyman series absorption components observed by FUSE. We find N(H I) = (9.0 +/- 1.0) x 10(19) cm(-2), N(D I) = (2.0 +/- 0.6) x 10(15) cm(-2), and N(O I) = (7.2 +/- 2.1) x 10(15) cm(-2) for the Complex C gas (68% confidence intervals). The corresponding light-element abundance ratios are D/H = (2.2 +/- 0.7) x 10(-5), O/H = (8.0 +/- 2.5) x 10(-5), and D/O = 0.28 +/- 0.12. The metallicity of Complex C gas toward PG 1259+593 is approximately 1/6 solar, as inferred from the oxygen abundance [O/H] = -0.79+/-(0.12)(0.16). While we cannot rule out a value of D/H similar to that found for the local ISM (i.e., D/H similar to 1.5 x 10(-5)), we can confidently exclude values as low as those determined recently for extended sight lines in the Galactic disk (D/H < 1 x 10(-5)). Combined with the sub-solar metallicity estimate and the low nitrogen abundance, this conclusion lends support to the hypothesis that Complex C is located outside the Milky Way, rather than inside in material recirculated between the Galactic disk and halo. The value of D/H for Complex C is consistent with the primordial abundance of deuterium inferred from recent Wilkinson Microwave Anisotropy Probe observations of the cosmic microwave simple chemical evolution models that predict the amount of deuterium astration as a function of metallicity. C1 Space Telescope Sci Inst, Baltimore, MD 21218 USA. Univ Wisconsin, Dept Astron, Madison, WI 53706 USA. Princeton Univ Observ, Princeton, NJ 08544 USA. Osserv Astrofis Arcetri, I-50125 Florence, Italy. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. Univ Colorado, Ctr Astrophys & Space Astron, Dept Astron & Planetary Sci, Boulder, CO 80309 USA. Univ Chicago, Dept Astron & Astrophys, Chicago, IL 60637 USA. Univ Chicago, Enrico Fermi Inst, Chicago, IL 60637 USA. NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. Inst Astrophys, F-75014 Paris, France. RP Sembach, KR (reprint author), Space Telescope Sci Inst, 3700 San Martin Dr, Baltimore, MD 21218 USA. RI Sonneborn, George/D-5255-2012; Kruk, Jeffrey/G-4047-2012; Jenkins, Edward/P-5684-2014 OI Jenkins, Edward/0000-0003-1892-4423 NR 117 TC 55 Z9 55 U1 0 U2 2 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 FEB PY 2004 VL 150 IS 2 BP 387 EP 415 DI 10.1086/381025 PG 29 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 769NN UT WOS:000188656800002 ER PT J AU Tabazadeh, A Cordero, EC AF Tabazadeh, A Cordero, EC TI New Directions: Stratospheric ozone recovery in a changing atmosphere SO ATMOSPHERIC ENVIRONMENT LA English DT Article C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. San Jose State Univ, San Jose, CA 95192 USA. RP Tabazadeh, A (reprint author), NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. EM azadeh.tabazadeh-1@nasa.gov; cordero@met.sjsu.edu NR 0 TC 12 Z9 12 U1 0 U2 0 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 1352-2310 J9 ATMOS ENVIRON JI Atmos. Environ. PD FEB PY 2004 VL 38 IS 4 BP 647 EP 649 DI 10.1016/j.atmosenv.2003.10.024 PG 3 WC Environmental Sciences; Meteorology & Atmospheric Sciences SC Environmental Sciences & Ecology; Meteorology & Atmospheric Sciences GA 770BA UT WOS:000188702200013 ER PT J AU Lyons, TJ Davenport, C Copley, GB Binder, H Grayson, K Kraft, NO AF Lyons, TJ Davenport, C Copley, GB Binder, H Grayson, K Kraft, NO TI Preventing G-induced loss of consciousness: 20 years of operational experience SO AVIATION SPACE AND ENVIRONMENTAL MEDICINE LA English DT Article DE G-induced loss of consciousness; G-LOC; centrifuge training; positive pressure breathing for G protection; PPG; risk homeostasis; accident epidemiology ID ACCELERATION; TOLERANCE AB Introduction: Although anecdotal reports of G-induced loss of consciousness (G-LOC) in military aviation date back to before 1920, regular reporting did not begin until 1982. The effectiveness in the operational setting of G-LOC preventive measures, such as positive pressure breathing for G protection (PBG), has not been studied. Methods: We use the term "crash" to represent an event where the aircraft was destroyed and "incident" to define those events where the crew reported a G-LOC episode and the aircraft was not damaged. Data on G-LOC crashes, incidents, and aircraft sorties (number of take-offs) were obtained from the USAF Safety Center database for FY 82-01. Results: During FY 82-01, there were 29 G-LOC crashes while those aircraft at risk of G-LOC crashes flew a total of 13,959,816 sorties. Poisson regression showed a non-significant decrease in in crashes with an incidence rate ratio (IRR) of 0.096 (CI 0.89-1.03) (4% per yr). G-LOC crashes decreased from 4.4 per million flight sorties (PMFS) to 1.6 after the implementation of anti-G-LOC training programs beginning in 1985. However, G-LOC crashes remained unchanged after implementation of PBG in 1995. In contrast, incidents showed an IRR of 1.04 (CI 1.02-1.06) for G-LOC incidents, an estimated increase of 5% per yr. Discussion: The physical/mechanical limitations of PBG, risk homeostasis, and the possibility that G-LOC rates have reached their asymptotic minimum are all discussed as possible explanations for the failure of PBG to decrease G-LOC crashes. C1 Asian Off Aerosp Res & Dev, Minato Ku, Tokyo 1060032, Japan. FAA SW Reg Directorate, Human Factors, Rotorcraft Stand Staff, Ft Worth, TX USA. HQ AF Safety Ctr, Res & Epidemiol Branch, Kirtland AFB, NM USA. NASA, Ames Res Ctr, SJSU Fdn, Human Factors Res & Technol Div, Moffett Field, CA 94035 USA. Inst Environm Safety & Occupat Hlth Risk Anal, Brooks City Base, TX USA. RP Lyons, TJ (reprint author), Asian Off Aerosp Res & Dev, Minato Ku, 7-23-17 Roppongi, Tokyo 1060032, Japan. EM lyonst@aoard.af.mil NR 15 TC 10 Z9 11 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 FEB PY 2004 VL 75 IS 2 BP 150 EP 153 PG 4 WC Public, Environmental & Occupational Health; Medicine, General & Internal; Sport Sciences SC Public, Environmental & Occupational Health; General & Internal Medicine; Sport Sciences GA 766PD UT WOS:000188384000008 PM 14960050 ER PT J AU Huang, HL Gumley, LE Strabala, K Li, J Weisz, E Rink, T Baggett, KC Davies, JE Smith, WL Dodge, JC AF Huang, HL Gumley, LE Strabala, K Li, J Weisz, E Rink, T Baggett, KC Davies, JE Smith, WL Dodge, JC TI International MODIS and AIRS processing package (IMAPP) - A direct broadcast software package for the NASA Earth Observing System SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article C1 Univ Wisconsin, Cooperat Inst Meteorol Satellite Studies, Madison, WI USA. NASA, Langley Res Ctr, Hampton, VA 23665 USA. NASA Headquarters, Washington, DC USA. RP Huang, HL (reprint author), 1225 W Dayton St, Madison, WI 53706 USA. EM allen.huang@ssec.wisc.edu RI Li, Jun/H-3579-2015 OI Li, Jun/0000-0001-5504-9627 NR 5 TC 27 Z9 28 U1 0 U2 2 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0003-0007 J9 B AM METEOROL SOC JI Bull. Amer. Meteorol. Soc. PD FEB PY 2004 VL 85 IS 2 BP 159 EP 161 DI 10.1175/BAMS-85-2-159 PG 3 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 801UW UT WOS:000220121800011 ER PT J AU Rossow, WB Duenas, EN AF Rossow, WB Duenas, EN TI The International Satellite Cloud Climatology Project (ISCCP) Web site - An online resource for research SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article ID SYSTEMS C1 NASA, SGT Inc, Goddard Inst Space Studies, New York, NY 10025 USA. RP Rossow, WB (reprint author), NASA, SGT Inc, Goddard Inst Space Studies, 2880 Broadway, New York, NY 10025 USA. EM wrossow@giss.nasa.gov RI Rossow, William/F-3138-2015 NR 6 TC 111 Z9 115 U1 0 U2 3 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0003-0007 J9 B AM METEOROL SOC JI Bull. Amer. Meteorol. Soc. PD FEB PY 2004 VL 85 IS 2 BP 167 EP 172 DI 10.1175/BAMS-85-2-167 PG 6 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 801UW UT WOS:000220121800012 ER PT J AU Weckwerth, TM Parsons, DB Koch, SE Moore, JA LeMone, MA Demoz, BB Flamant, C Geerts, B Wang, JH Feltz, WF AF Weckwerth, TM Parsons, DB Koch, SE Moore, JA LeMone, MA Demoz, BB Flamant, C Geerts, B Wang, JH Feltz, WF TI An overview of the International H2O Project (IHOP_2002) and some preliminary highlights SO BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY LA English DT Article ID CONVECTIVE BOUNDARY-LAYER; WATER-VAPOR; DOPPLER RADAR; RAMAN LIDAR; SQUALL LINE; TOGA-COARE; ATMOSPHERIC SOLITARY; SYSTEM DESCRIPTION; HUMIDITY; CLOUD AB The International H2O Project (IHOP_2002) is one of the largest North American meteorological field experiments in history. From 13 May to 25 June 2002, over 250 researchers and technical staff from the United States, Germany, France, and Canada converged on the Southern Great Plains to measure water vapor and other atmospheric variables. The principal objective of IHOP - 2002 is to obtain an improved characterization of the time-varying three-dimensional water vapor field and evaluate its utility in improving the understanding and prediction of convective processes. The motivation for this objective is the combination of extremely low forecast skill for warm-season rainfall and the relatively large loss of life and property from flash floods and other warm-season weather hazards. Many prior studies on convective storm forecasting have shown that water vapor is a key atmospheric variable that is insufficiently measured. Toward this goal, IHOP-2002 brought together many of the existing operational and new state-of-the-art research water vapor sensors and numerical models. The IHOP - 2002 experiment comprised numerous unique aspects. These included several instruments fielded for the first time (e.g., reference radiosonde); numerous upgraded instruments (e.g., Wyoming Cloud Radar); the first ever horizontal-pointing water vapor differential absorption lidar (DIAL; i.e., Leandre II on the Naval Research Laboratory P-3), which required the first onboard aircraft avoidance radar; several unique combinations of sensors (e.g., multiple profiling instruments at one field site and the German water vapor DIAL and NOAA/Environmental Technology Laboratory Doppler lidar on board the German Falcon aircraft); and many logistical challenges. This article presents a summary of the motivation, goals, and experimental design of the project, illustrates some preliminary data collected, and includes discussion on some potential operational and research implications of the experiment. C1 Natl Ctr Atmospher Res, ATD, POB 3000, Boulder, CO 80307 USA. NOAA Res, Forecast Syst Lab, Boulder, CO USA. Univ Corp Atmospher Res, Joint Off Sci Support, Boulder, CO USA. Natl Ctr Atmospher Res, Mesoscale & Microscale Meteorol Div, Boulder, CO 80307 USA. NASA, Mesoscale Atmospher Proc Branch, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Paris 06, Inst Pierre Simon Laplace, CNRS, Serv Aeron, Paris, France. Univ Wyoming, Dept Atmospher Sci, Laramie, WY 82071 USA. Univ Wisconsin, Ctr Space Sci & Engn, Cooperat Inst Meteorol Satellite Studies, Madison, WI 53706 USA. RP Natl Ctr Atmospher Res, ATD, POB 3000, Boulder, CO 80307 USA. EM tammy@ucar.edu RI Y, wang/A-8866-2010; Demoz, Belay/N-4130-2014 NR 84 TC 251 Z9 253 U1 3 U2 25 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0003-0007 EI 1520-0477 J9 B AM METEOROL SOC JI Bull. Amer. Meteorol. Soc. PD FEB PY 2004 VL 85 IS 2 BP 253 EP 277 DI 10.1175/BAMS-85-2-253 PG 25 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 801UW UT WOS:000220121800019 ER PT J AU Stoner, AW Sturm, EA AF Stoner, AW Sturm, EA TI Temperature and hunger mediate sablefish (Anoplopoma fimbria) feeding motivation: implications for stock assessment SO CANADIAN JOURNAL OF FISHERIES AND AQUATIC SCIENCES LA English DT Article ID BEHAVIORAL-RESPONSES; PACIFIC HALIBUT; GROWTH; BAIT AB Laboratory experiments were conducted to test the hypothesis that temperature (2-8degreesC) and recent feeding history (1-6 days of food deprivation) influence feeding motivation and attacks on baits by adult sablefish (Anoplo poma fimbria). Activity level after introduction of a bait-related olfactory cue increased with increasing water temperature and food deprivation. Fish at the lowest temperature (2degreesC) attacked and consumed fewer squid baits (33-71%) than those at higher temperatures (100% at 8degreesC). Baits were frequently inspected or handled multiple times before consumption in low temperatures, and time to attack (seconds to >40 min), time to consume, and time to handle baits (2-20 s) all decreased significantly with increasing temperature, with some temperature x feeding history interactions. The total ration consumed increased (<1-8% of body weight) with increasing water temperature. The observed variability in activity and feeding motivation in sablefish may have a large impact on the effective area of baited gear but is rarely considered in stock assessment models. In particular, population sizes based upon baited gear surveys may be underestimated in conditions where temperature is low, natural prey density is high, or where other environmental variables reduce feeding motivation. C1 Natl Marine Fisheries Serv, Fisheries Behav Ecol Program, Alaska Fisheries Sci Ctr, NOAA, Newport, OR 97365 USA. RP Stoner, AW (reprint author), Natl Marine Fisheries Serv, Fisheries Behav Ecol Program, Alaska Fisheries Sci Ctr, NOAA, 2030 S Marine Sci Dr, Newport, OR 97365 USA. EM al.stoner@noaa.gov NR 26 TC 18 Z9 20 U1 0 U2 5 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 FEB PY 2004 VL 61 IS 2 BP 238 EP 246 DI 10.1139/F03-170 PG 9 WC Fisheries; Marine & Freshwater Biology SC Fisheries; Marine & Freshwater Biology GA 810MV UT WOS:000220709300010 ER PT J AU Chipman, JW Lillesand, TM Schmaltz, JE Leale, JE Nordheim, MJ AF Chipman, JW Lillesand, TM Schmaltz, JE Leale, JE Nordheim, MJ TI Mapping lake water clarity with Landsat images in Wisconsin, USA SO CANADIAN JOURNAL OF REMOTE SENSING LA English DT Article; Proceedings Paper CT Workshop on Remote Sensing and Resource Management in Nearshore and Inland Waters CY OCT 22-24, 2001 CL Wolfville, CANADA ID QUALITY AB Landsat thematic mapper (TM) and enhanced thematic mapper plus (ETM+) images are being used to map lake water clarity region-wide in the Upper Midwest states of Minnesota, Wisconsin, and Michigan using a standardized image processing protocol. In Wisconsin, lake clarity estimates have been produced for 8645 lakes in the 1999-2001 time period. In addition to satellite imagery, the protocol relies on Secchi disk data collected by a network of citizen volunteers for development and validation of models. The most significant term in the regression model relating the satellite imagery to the field data is the ratio of spectral radiance values in the blue and red bands (ratio of Landsat band 1 to Landsat band 3). The resulting database of satellite-derived lake water clarity estimates represents an important new resource for lake managers in the region, and for those studying the linkages between lakes and their surrounding landscapes. C1 Univ Wisconsin, Ctr Environm Remote Sensing, Madison, WI 53706 USA. Univ Wisconsin, Ctr Limnol, Madison, WI 53706 USA. NASA, Goddard Space Flight Ctr, MODIS Rapid Response Team, Greenbelt, MD 20771 USA. RP Chipman, JW (reprint author), Univ Wisconsin, Ctr Environm Remote Sensing, 1225 W Dayton St, Madison, WI 53706 USA. EM jchipman@wisc.edu NR 18 TC 36 Z9 36 U1 1 U2 16 PU CANADIAN AERONAUTICS SPACE INST PI OTTAWA PA 1685 RUSSELL RD, UNIT 1-R, OTTAWA, ON K1G 0N1, CANADA SN 0703-8992 J9 CAN J REMOTE SENS JI Can. J. Remote Sens. PD FEB PY 2004 VL 30 IS 1 BP 1 EP 7 PG 7 WC Remote Sensing SC Remote Sensing GA 778AK UT WOS:000189216800002 ER PT J AU Zak, M AF Zak, M TI Self-supervised dynamical systems SO CHAOS SOLITONS & FRACTALS LA English DT Article ID INFORMATION AB A new type of dynamical systems which capture the interactions via information flows typical for active multi-agent systems is introduced. The mathematical formalism is based upon coupling the classical dynamical system (with random components caused by uncertainties in initial conditions as well as by Langevin forces) with the corresponding Liouville or the Fokker-Planck equations describing evolution of these uncertainties in terms of probability density. The coupling is implemented by information-based supervising forces which fundamentally change the patterns of probability evolution. It is demonstrated that the probability density can approach prescribed attractors while exhibiting such patterns as shock waves, solitons and chaos in probability space. Applications of these phenomena to information-based neural nets, expectation-based cooperation, self-programmed systems, control chaos using terminal attractors as well as to games with incomplete information, are addressed. A formal similarity between the mathematical structure of the introduced dynamical systems and quantum mechanics is discussed. (C) 2003 Elsevier Ltd. All rights reserved. C1 CALTECH, Jet Prop Lab, Ultracomp Grp, Pasadena, CA 91109 USA. Oak Ridge Natl Lab, Ctr Engn Syst Adv Res, Oak Ridge, TN 37831 USA. RP Zak, M (reprint author), CALTECH, Jet Prop Lab, Ultracomp Grp, 4800 Oak Grove Dr,M-S 126-347, Pasadena, CA 91109 USA. NR 18 TC 8 Z9 8 U1 1 U2 2 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 FEB PY 2004 VL 19 IS 3 BP 645 EP 666 DI 10.1016/S0960-0779(03)00196-6 PG 22 WC Mathematics, Interdisciplinary Applications; Physics, Multidisciplinary; Physics, Mathematical SC Mathematics; Physics GA 726BG UT WOS:000185577600019 ER PT J AU Okai, K Ueda, T Imamura, O Tsue, M Kono, M Sato, J Dietrich, DL Williams, FA AF Okai, K Ueda, T Imamura, O Tsue, M Kono, M Sato, J Dietrich, DL Williams, FA TI Effects of DC electric fields on combustion of octane droplet pairs in microgravity SO COMBUSTION AND FLAME LA English DT Article ID THIN-FLAME THEORY; FUEL DROPLET C1 Japan Aerosp Explorat Agcy, Inst Space Technol & Aeronaut, Chofu, Tokyo 1828522, Japan. Univ Tokyo, Tokyo 1138656, Japan. Ishikawajima Harima Heavy Ind Co Ltd, Tokyo 1350061, Japan. NASA, John H Glenn Res Ctr, Cleveland, OH 44135 USA. Univ Calif San Diego, La Jolla, CA 92093 USA. RP Okai, K (reprint author), Japan Aerosp Explorat Agcy, Inst Space Technol & Aeronaut, 7-44-1,Jindaiji Higashimachi, Chofu, Tokyo 1828522, Japan. EM okai.keiichi@jaxa.jp NR 8 TC 5 Z9 6 U1 1 U2 2 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 FEB PY 2004 VL 136 IS 3 BP 390 EP 393 DI 10.1016/j.combustflame.2003.11.003 PG 4 WC Thermodynamics; Energy & Fuels; Engineering, Multidisciplinary; Engineering, Chemical; Engineering, Mechanical SC Thermodynamics; Energy & Fuels; Engineering GA 774ZD UT WOS:000189015500012 ER PT J AU Gentz, M Armentrout, D Rupnowski, P Kumosa, L Shin, E Sutter, JK Kumosa, M AF Gentz, M Armentrout, D Rupnowski, P Kumosa, L Shin, E Sutter, JK Kumosa, M TI In-plane shear testing of medium and high modulus woven graphite fiber reinforced/polyimide composites SO COMPOSITES SCIENCE AND TECHNOLOGY LA English DT Article ID SPECIMENS; LOADS AB Iosipescu shear tests were performed at room temperature and at 316 degreesC (600 degreesF) on woven composites with either M40J or M60J graphite fibers and PMR-II-50 polyimide resin matrix. The composites were tested as supplied and after thermo-cycling, with the thermo-cycled composites being tested under dry and wet conditions. Acoustic emission (AE) was monitored during the room and high temperature Iosipescu experiments. The shear stresses at the maximum loads and the shear stresses at the significant onset of AE were determined for the composites as a function of temperature and conditioning. The combined effects of thermo-cycling and moisture on the strength and stiffness properties of the composites were evaluated. It was determined that the room and high temperature shear stresses at the maximum loads were unaffected by conditioning. However, at room temperature the significant onset of AE was affected by conditioning; the thermal-conditioned wet specimens showed the highest shear stress at the onset of AE followed by thermal-conditioned and then as received specimens. Also, at high temperature the significant onset of AE occurred in some specimens after the maximum load due to the viscoelastoplastic nature of the matrix material. (C) 2003 Elsevier Ltd. All rights reserved. C1 Univ Denver, Dept Engn, Ctr Adv Mat & Struct, Denver, CO 80208 USA. NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Kumosa, M (reprint author), Univ Denver, Dept Engn, Ctr Adv Mat & Struct, 2390 S York St, Denver, CO 80208 USA. RI Rupnowski, Przemyslaw/B-3520-2008; OI Rupnowski, Przemyslaw/0000-0003-0040-418X NR 16 TC 25 Z9 28 U1 2 U2 11 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0266-3538 J9 COMPOS SCI TECHNOL JI Compos. Sci. Technol. PD FEB PY 2004 VL 64 IS 2 BP 203 EP 220 DI 10.1016/S0266-3538(03)00260-4 PG 18 WC Materials Science, Composites SC Materials Science GA 759PJ UT WOS:000187745800005 ER PT J AU Ramachandran, R Graves, S Conover, H Moe, K AF Ramachandran, R Graves, S Conover, H Moe, K TI Earth Science Markup Language (ESML): a solution for scientific data-application interoperability problem SO COMPUTERS & GEOSCIENCES LA English DT Article DE interchange technology; interoperability; ESML; XML; data formats ID MEANINGFUL AB Interchange technologies facilitate seamless interactions between applications, tools and services with datasets in heterogeneous formats. The Information Technology and Systems Center at the University of Alabama in Huntsville is developing an interchange technology focused on scientific data in general, and particularly on the vast amounts of remotely sensed Earth Science data. This interchange technology consists of the Earth Science Markup Language (ESML) and a related library of programming utilities. ESML, based on the eXtensible Markup Language (XML), allows data format structure descriptions to be written in a standard manner. ESML is unique in that it is not another new data format, instead it is a external structural metadata based solution for decoding existing formats. The effort involved to describe legacy data formats in ESML is small. ESML and the associated software library will allow wider interoperability of Earth Science services and tools, enabling Earth Scientists to work more easily with data in a variety of formats. This interchange technology will facilitate the development of data format independent search, visualization, and analysis tools. This paper will describe this interchange technology and compare it with similar XML based efforts. (C) 2003 Elsevier Ltd. All rights reserved. C1 Univ Alabama, Informat Technol & Syst Ctr, Huntsville, AL 35899 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Ramachandran, R (reprint author), Univ Alabama, Informat Technol & Syst Ctr, Huntsville, AL 35899 USA. EM rramachandran@itsc.uah.edu NR 6 TC 21 Z9 21 U1 0 U2 3 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0098-3004 J9 COMPUT GEOSCI-UK JI Comput. Geosci. PD FEB PY 2004 VL 30 IS 1 BP 117 EP 124 DI 10.1016/j.cageo.2003.08.010 PG 8 WC Computer Science, Interdisciplinary Applications; Geosciences, Multidisciplinary SC Computer Science; Geology GA 774MD UT WOS:000188982500010 ER PT J AU Conmy, RN Coble, PG Del Castillo, CE AF Conmy, RN Coble, PG Del Castillo, CE TI Calibration and performance of a new in situ multi-channel fluorometer for measurement of colored dissolved organic matter in the ocean SO CONTINENTAL SHELF RESEARCH LA English DT Article DE fluorescence; CDOM; in situ instrumentation; optical properties; SAFIre ID OPTICAL-PROPERTIES; ORINOCO RIVER; FLUORESCENCE; SPECTROSCOPY; ABSORPTION; SEAWATER; PLUME AB The development of multispectral in situ fluorescence instruments greatly enhances the study of the optical properties of Colored Organic Matter (COM). Here, we tested the inter-instrument variability of three WetLabs, Inc. SAFIres using quinine sulfate standards. As with any fluorometer, intensity and spectral biases in fluorescence output due to properties of the SAFIre's optical components necessitate corrections. Low response of the instrument to quinine sulfate and lack of an excitation/emission channel at the fluorescence maximum of this standard precluded direct spectral calibration. Calibrations conducted using seawater as a secondary standard provided an acceptable alternative. The field performance of the SAFIre from two experiments is presented here. Time series Contour plots show that the instrument has the ability to detect small differences in COM optical properties, and observed fluorescence emission ratios Lire indicative of changes in sources of the material over the course of the study. The SAFIre was found to extend multispectral measurements to include high spatial and high temporal resolution. (C) 2003 Elsevier Ltd. All rights reserved. C1 Univ S Florida, Dept Marine Sci, St Petersburg, FL 33701 USA. NASA, Geosp Appl & Dev Directorate, Stennis Space Ctr, MS 39529 USA. RP Conmy, RN (reprint author), Univ S Florida, Dept Marine Sci, 140 7Th Ave S, St Petersburg, FL 33701 USA. EM rconmy@marine.usf.edu RI Del Castillo, Carlos/N-2601-2013 NR 17 TC 22 Z9 22 U1 2 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 FEB PY 2004 VL 24 IS 3 BP 431 EP 442 DI 10.1016/j.csr.2003.10.010 PG 12 WC Oceanography SC Oceanography GA 800JY UT WOS:000220025800008 ER PT J AU Righter, K Campbell, AJ Humayun, M Hervig, RL AF Righter, K Campbell, AJ Humayun, M Hervig, RL TI Partitioning of Ru, Rh, Pd, Re, Ir, and Au between Cr-bearing spinel, olivine, pyroxene and silicate melts SO GEOCHIMICA ET COSMOCHIMICA ACTA LA English DT Article ID PLATINUM-GROUP ELEMENTS; CORE-MANTLE INTERACTION; HIGH-TEMPERATURES; THERMODYNAMIC DATA; REDOX REACTIONS; OXYGEN BUFFER; EXPERIMENTAL CONSTRAINTS; SULFIDE LIQUID; GORGONA-ISLAND; OCEANIC-CRUST AB A series of high temperature experiments was undertaken to study partitioning of several highly siderophile elements (HSE; Ru, Rh, Pd, Re, Os, Ir, Pt and Au) between Cr-rich spinel, olivine, pyroxene and silicate melt. Runs were carried out on a Hawaiian ankaramite, a synthetic eucrite basalt, and a DiAn eutectic melt, at one bar, 19 kbar, and 20 kbar, respectively, in the temperature range of 1200 to 1300 C, at oxygen fugacities between the nickel-nickel oxide (NNO) and hematite-magnetite (HM) oxygen buffers. High oxygen fugacities were used to suppress the formation of HSE-rich "nuggets" in the silicate melts. The resulting oxide and silicate crystals (<100 mum) were analyzed using both SIMS and LA-ICP-MS, with a spatial resolution of 15 to 50 mum. Rhenium, Au and Pd were all found to be incompatible in Cr-rich spinel (D-Re(sp/melt) = 0.0012-0.21, D-Au(sp/melt) = 0.076, D-Pd(sp/melt) = 0.14), whereas Rh, Ru and It were all found to be highly compatible (D-Rh(sp/melt) = 41-530, D-Ru(sp/melt) = 76-1143, D-Ir(sp/melt) = 5-22000). Rhenium, Pd,Au and Ru were all found to be incompatible in olivine (D-Re(oliv/melt) = 0.017-0.073, D-Pd(oliv/melt) = 0.12, D-Au(oliv/melt) = 0.12, D-Ru(oliv/melt) = 0.23), Re is incompatible in orthopyroxene and clinopyroxene (D-Re(opx/melt) = 0.013, D-Re(cpx/melt) = 0.18-0.21), and Pt is compatible in clinopyroxene (D-Pt(cpx/melt) = 1.5). The results are compared to and combined with previous work on HSE partitioning among spinet-structured oxides, and applied to some natural magmatic suites to demonstrate consistency. Copyright (C) 2004 Elsevier Ltd. C1 Univ Arizona, Lunar & Plant Lab, Tucson, AZ 85721 USA. Univ Chicago, Dept Geophys Sci, Chicago, IL 60637 USA. Arizona State Univ, Ctr Solid State Sci, Tempe, AZ 85287 USA. RP Righter, K (reprint author), NASA, Lyndon B Johnson Space Ctr, 2101 NASA Rd 1,Mailcode ST, Houston, TX 77058 USA. EM kevin.righter-l@nasa.gov OI Humayun, Munir/0000-0001-8516-9435 NR 71 TC 177 Z9 197 U1 4 U2 29 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 FEB PY 2004 VL 68 IS 4 BP 867 EP 880 DI 10.1016/j.gca.2003.07.005 PG 14 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 773DM UT WOS:000188882500014 ER PT J AU Bleck, R Sun, S AF Bleck, R Sun, S TI Diagnostics of the oceanic thermohaline circulation in a coupled climate model SO GLOBAL AND PLANETARY CHANGE LA English DT Article DE oceanic thermohaline circulation; climate model; HYCOM ID SOUTHERN-OCEAN; TRANSFORMATION; ATMOSPHERE; FORCINGS AB Two century-scale integrations of a global coupled model consisting of the GISS atmospheric model and the HYCOM ocean model are carried out: a control run assuming fixed atmospheric composition, and a perturbation run assuming gradual doubling Of CO2. The model does not use flux corrections at the air-sea interface, nor is the ocean "spun up" prior to coupling: When increasing CO2 at the rate of 1% per year to twice its original level and keeping it constant thereafter, the model responds with a 2 degreesC increase in 200 years in the global mean surface air temperature and a virtually unchanged Atlantic meridional overturning circulation (MOC). Due to the predominantly isopycnic character of HYCOM, geographic details of the 3-D thermohaline circulation in potential density space can be extracted from the model output with relative ease. The analysis confirms that even regional details of the MOC in this experiment are rather insensitive to the climate change brought on by CO2 doubling. Furthermore, the analysis reveals strong similarities between the simulated and the observed MOC. (C) 2003 Elsevier B.V. All rights reserved. C1 Los Alamos Natl Lab, Los Alamos, NM 87545 USA. NASA, Goddard Inst Space Studies, New York, NY 10025 USA. RP Bleck, R (reprint author), Los Alamos Natl Lab, Mail Stop B296, Los Alamos, NM 87545 USA. EM bleck@lanl.gov RI Sun, Shan/H-2318-2015 NR 19 TC 8 Z9 8 U1 0 U2 4 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0921-8181 J9 GLOBAL PLANET CHANGE JI Glob. Planet. Change PD FEB PY 2004 VL 40 IS 3-4 BP 233 EP 248 DI 10.1016/j.gloplacha.2003.04.002 PG 16 WC Geography, Physical; Geosciences, Multidisciplinary SC Physical Geography; Geology GA 762JC UT WOS:000187967500002 ER PT J AU Sorof, JM Turner, J Martin, DS Garcia, K Garami, Z Alexandrov, AV Wan, F Portman, RJ AF Sorof, JM Turner, J Martin, DS Garcia, K Garami, Z Alexandrov, AV Wan, F Portman, RJ TI Cardiovascular risk factors and sequelae in hypertensive children identified by referral versus school-based screening SO HYPERTENSION LA English DT Article DE obesity; hypertension; children; echocardiography; cardiovascular diseases ID LEFT-VENTRICULAR HYPERTROPHY; AMBULATORY BLOOD-PRESSURE; WHITE COAT HYPERTENSION; BODY-SIZE; ADOLESCENTS; MASS; ABNORMALITIES; OBESITY; ADULTS AB To determine whether systematic differences exist between hypertensive children referred for evaluation by primary care providers and children identified through community-based screening, cardiovascular risk factors and surrogate markers of hypertensive injury were compared based on subject source ( referral versus screening). Children referred to a hypertension clinic for persistently elevated blood pressure were compared with children identified as hypertensive during school screening of 5102 students in Houston public schools. M-mode echocardiography of the left ventricle was performed and subsequently reviewed by 2 independent sonographers blinded to identifying subject information. Subsets of subjects also underwent carotid artery ultrasound for measurement of intimal-medial thickness, overnight urine collections for microalbuminuria, and fasting serum cholesterol, triglycerides, and glucose. Ninety-seven total subjects ( 54 screening and 43 referral) met inclusion criteria and had technically adequate echocardiography performed. The prevalence of left ventricular hypertrophy (LVH) was 37%. Referral subjects demonstrated significantly greater left ventricular mass index (38.8 versus 34.2 g/ m(2.7); P < 0.01) and a higher prevalence of LVH (49% versus 28%; P < 0.05). Among subjects who underwent carotid ultrasound ( n = 75), carotid intimal-medial thickness was significantly higher in referral subjects (0.61 versus 0.57, P < 0.05). When controlling for BMI z score, which was significantly higher in referral subjects, systematic differences by subject source did not persist. These findings suggest that hypertensive children who are predominantly overweight, independent of the manner in which patients come to medical attention, will manifest evidence of more severe cardiovascular disease assessed by surrogate markers such as left ventricular mass index or carotid artery intimal medial thickness. C1 Univ Texas, Houston Sch Med, Div Pediat Nephrol & Hypertens, Dept Pediat, Houston, TX 77030 USA. Univ Texas, Houston Sch Med, Dept Neurol, Houston, TX 77030 USA. NASA, Lyndon B Johnson Space Ctr, Wyle Labs, Cardiovasc Lab, Houston, TX 77058 USA. RP Sorof, JM (reprint author), Univ Texas, Houston Sch Med, Div Pediat Nephrol & Hypertens, Dept Pediat, 6431 Fannin St,Rm 3-124, Houston, TX 77030 USA. EM jonathan.m.sorof@uth.tmc.edu OI Alexandrov, Andrei V/0000-0001-8871-1023 FU NHLBI NIH HHS [K23 HL04217] NR 29 TC 33 Z9 35 U1 0 U2 0 PU LIPPINCOTT WILLIAMS & WILKINS PI PHILADELPHIA PA 530 WALNUT ST, PHILADELPHIA, PA 19106-3621 USA SN 0194-911X J9 HYPERTENSION JI Hypertension PD FEB PY 2004 VL 43 IS 2 BP 214 EP 218 DI 10.1161/01.HYP.0000114696.96318.4e PG 5 WC Peripheral Vascular Disease SC Cardiovascular System & Cardiology GA 768KD UT WOS:000188541400016 PM 14744920 ER PT J AU Cochran, AL Vilas, F Jarvis, KS Kelley, MS AF Cochran, AL Vilas, F Jarvis, KS Kelley, MS TI Investigating the Vesta-vestoid-HED connection SO ICARUS LA English DT Article DE asteroids; asteroids, composition; asteroids, Vesta; spectrophotometry; surfaces, asteroids ID BASALTIC METEORITES; NEAR-EARTH; ASTEROIDS; SURFACE; HOWARDITE; SPECTRUM; MYSTERY; EUCRITE; BODIES; ORIGIN AB We present spectral observations of Minor Planet 4 Vesta, of five V-type asteroids which are physically near Vesta, and of two V-type NEAs. We use these spectra to determine the presence or absence of a weak feature at 506.5 nm which is indicative of the presence of spin-forbidden Fe2+ in sixfold coordination. As with our earlier observations [Cochran and Vilas, Icarus 134 (1998) 207-212], we find this feature at all observed rotational phases of Vesta and again see the trend that spectra at longitudes between 240degrees and 360degrees have a smaller 506.5 nm feature equivalent width than spectra obtained at other longitudes. Additionally, we searched for this feature in V-class main-belt and NEA asteroids and positively detected the feature in main-belt Asteroid 2579 Spartacus and possibly in 3376 Armandhammer. The other objects lacked the feature. Our results are compared with previous observations of this feature by Vilas et al. [Icarus 147 (2000) 119-128]. The spatial distribution of the bodies as a function of the presence of this feature was investigated. We discuss the implication of the presence of this feature and the depth of the 0.9 mum pyroxene band for the scenario that pieces of Vesta were transported, via the 3:1 and nu(6) resonances, to the NEAs, and thence to inclusion in our meteorite collections as HED meteorites. (C) 2003 Published by Elsevier Inc. C1 Univ Texas, Dept Astron, Austin, TX 78712 USA. Lockheed Martin Space Operat, Houston, TX 77058 USA. Georgia So Univ, Dept Geol & Geog, Statesboro, GA 30460 USA. NASA, Johnson Space Ctr SR, Houston, TX 77058 USA. RP Cochran, AL (reprint author), Univ Texas, Dept Astron, 1 Univ Stn,C1400, Austin, TX 78712 USA. EM anita@barolo.as.utexas.edu; faith.vilas1@jsc.pasa.gov; kandy.s.jarvis1@jsc.nasa.gov; mkelley@gasou.edu NR 30 TC 15 Z9 15 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 FEB PY 2004 VL 167 IS 2 BP 360 EP 368 DI 10.1016/j.icarus.2003.10.007 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 802KA UT WOS:000220161200009 ER PT J AU Sulima, OV Mauk, MG Shellenbarger, ZA Cox, JA Li, JV Sims, PE Datta, S Rafol, SB AF Sulima, OV Mauk, MG Shellenbarger, ZA Cox, JA Li, JV Sims, PE Datta, S Rafol, SB TI Uncooled low-voltage AlGaAsSb/lnGaAsSb/GaSb avalanche photodetectors SO IEE PROCEEDINGS-OPTOELECTRONICS LA English DT Article ID MIDINFRARED WAVELENGTHS; INASSBP PHOTODETECTORS; GAINASSB; PROGRESS AB Low-voltage AlGaAsSb/InGaAsSb/GaSb separate absorption and multiplication avalanche photodiodes (SAM-APD), as well as InGaAsSb/GaSb APDs with an AlGaAsSb passivating layer, are fabricated using liquid phase epitaxy. Formation of the p-n junction is performed either epitaxially or through diffusion of Zn from the vapour phase. Responsivity as high as 43 A/W at wavelength of 2 100 nm is achieved at room temperature in AlGaAsSb/InGaAsSb/GaSb SAM-APDs reverse biased at 6.7 V. Relatively high responsivity (8.9 A/W at 2000 nm) was also measured in an InGaAsSb/GaSb APD reverse biased at 7.5 V. C1 AstroPower Inc, Newark, DE 19716 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Sulima, OV (reprint author), AstroPower Inc, Solar Pk, Newark, DE 19716 USA. RI Li, Jian/B-1627-2016 NR 9 TC 24 Z9 24 U1 0 U2 10 PU IEE-INST ELEC ENG PI HERTFORD PA MICHAEL FARADAY HOUSE SIX HILLS WAY STEVENAGE, HERTFORD SG1 2AY, ENGLAND SN 1350-2433 J9 IEE P-OPTOELECTRON JI IEE Proc.-Optoelectron. PD FEB PY 2004 VL 151 IS 1 BP 1 EP 5 DI 10.1049/ip-opt:20040142 PG 5 WC Engineering, Electrical & Electronic; Optics; Telecommunications SC Engineering; Optics; Telecommunications GA 777UK UT WOS:000189196500001 ER PT J AU Gawronski, W AF Gawronski, W TI Modeling wind-gust disturbances for the analysis of antenna pointing accuracy SO IEEE ANTENNAS AND PROPAGATION MAGAZINE LA English DT Article DE antennas; antenna mechanical factors; antenna transient analysis; control systems; control engineering; reflector antenna mechanical factors AB This paper develops and compares three wind models used to simulate antenna pointing errors. The first model represents wind forces acting on the antenna dish, thus closely representing actual wind action. The second model represents wind gusts as torque disturbances applied at the antenna drives. The third model represents gusts acting at the antenna rate input. A wind filter, introduced in this paper, makes the wind gusts of the third model equivalent to the gusts of the second model. The third model is applicable to the currently developed models of the antenna's closed-loop systems. Simulink models of the 34-meter and 70-meter antennas' closed-loop system were used to simulate antenna pointing errors in wind gusts. The paper shows that for the NASA 34-meter and for the 70-meter antennas, all three models give similar results, and the results are comparable with field measurements of the servo errors taken in wind. C1 CALTECH, Jet Prop Lab, Commun Ground Syst Sect, Pasadena, CA 91109 USA. RP Gawronski, W (reprint author), CALTECH, Jet Prop Lab, Commun Ground Syst Sect, MS 238-528,4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM wodek.k.gawronski@jpl.nasa.gov NR 8 TC 10 Z9 14 U1 0 U2 4 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 1045-9243 EI 1558-4143 J9 IEEE ANTENN PROPAG M JI IEEE Antennas Propag. Mag. PD FEB PY 2004 VL 46 IS 1 BP 50 EP 58 DI 10.1109/MAP.2004.1296144 PG 9 WC Engineering, Electrical & Electronic; Telecommunications SC Engineering; Telecommunications GA 813ED UT WOS:000220889500003 ER PT J AU Samoska, L Peralta, A Hu, M Micovic, M Schmitz, A AF Samoska, L Peralta, A Hu, M Micovic, M Schmitz, A TI A 20 mW, 150 GHz InPHEMT MMIC power amplifier module SO IEEE MICROWAVE AND WIRELESS COMPONENTS LETTERS LA English DT Article DE HEMTs; millimeter-wave power amplifiers; MMIC amplifiers AB This paper describes a power amplifier (PA) module containing an InP High Electron Mobility Transistor (HEMT) Monolithic Millimeter-wave Integrated Circuit (MMIC) amplifier chip, designed, and packaged at the Jet Propulsion Laboratory, and fabricated at HRL Laboratories. The module features 20 mW of output power at 150 GHz, with more than 10 mW available in the 148-160 GHz frequency range. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. HRL Labs LLC, Malibu, CA USA. RP CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM lorene@merlin.jpl.nasa.gov; schmitz@hrl.com NR 9 TC 20 Z9 22 U1 0 U2 4 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855-4141 USA SN 1531-1309 EI 1558-1764 J9 IEEE MICROW WIREL CO JI IEEE Microw. Wirel. Compon. Lett. PD FEB PY 2004 VL 14 IS 2 BP 56 EP 58 DI 10.1109/LMWC.2003.822575 PG 3 WC Engineering, Electrical & Electronic SC Engineering GA 778YM UT WOS:000189269000002 ER PT J AU Li, L Njoku, EG Im, E Chang, PS Germain, KS AF Li, L Njoku, EG Im, E Chang, PS Germain, KS TI A preliminary survey of radio-frequency interference over the US in Aqua AMSR-E data SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE advanced microwave scanning radiometer (AMSR); microwave radiometry; radio-frequency interference (RFI); land remote sensing ID RADIOMETER AB A spectral difference method is used to quantify the magnitude and extent of radio-frequency interference (RFI) observed over the United States in the Aqua AMSR-E radiometer channels. A survey using data from the AMSR-E instrument launched in May 2002 shows the interference to be widespread in the C-band (6.9 GHz) channels. The RFI is located mostly, but not always, near large highly populated urban areas. The locations of interference are persistent in time, but the magnitudes show temporal and directional variability. Strong and moderate RFI can be identified relatively easily using an RFI index derived from the spectral difference between the 6.9- and 10.7-GHz channels. Weak RFI is difficult to distinguish, however, from natural geophysical variability. These findings have implications for future microwave sensing at C-band, particularly over land areas. An innovative concept for radiometer system design is also discussed as a possible mitigation approach. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. NOAA, Off Res & Applicat, Natl Environm Satellite Data & Informat Serv, Camp Springs, MD 20746 USA. USN, Res Lab, Remote Sensing Div, Washington, DC 20375 USA. RP Li, L (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM li.li@jpl.nasa.gov; eni.g.njoku@jpl.nasa.gov; eastwood.im@jpl.nasa.gov; paul.s.chang@noaa.gov; karen.Stgermain@nrl.navy.mil RI Chang, Paul/F-5580-2010 OI Chang, Paul/0000-0001-5113-0938 NR 13 TC 114 Z9 123 U1 2 U2 14 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD FEB PY 2004 VL 42 IS 2 BP 380 EP 390 DI 10.1109/TGRS.2003.817195 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 773XA UT WOS:000188949600012 ER PT J AU Piepmeier, JR AF Piepmeier, JR TI Calibration of passive microwave polarimeters that use hybrid coupler-based correlators SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE calibration; correlators; microwave radiometry; polarimetry; polarization ID RADIOMETER; BAND AB Four calibration algorithms are studied for microwave polarimeters that use hybrid coupler-based correlators: 1) conventional two-look of hot and cold sources; 2) three looks of hot and cold source combinations; 3) two-look with correlated source; and 4) four-look combining methods 2) and 3). The systematic errors are found to depend on the polarimeter component parameters and accuracy of calibration noise temperatures. A case study radiometer in four different remote sensing scenarios was considered in light of these results. Applications for ocean surface salinity, ocean surface winds, and soil moisture were found to be sensitive to different systematic errors. Finally, a standard uncertainty analysis was performed on the four-look calibration algorithm, which was found to be most sensitive to the correlated calibration source. C1 NASA, Goddard Space Flight Ctr, Microwave Instrument Technol Branch, Greenbelt, MD 20771 USA. RP Piepmeier, JR (reprint author), NASA, Goddard Space Flight Ctr, Microwave Instrument Technol Branch, Greenbelt, MD 20771 USA. EM jeff.piepmeier@nasa.gov NR 13 TC 10 Z9 10 U1 0 U2 1 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD FEB PY 2004 VL 42 IS 2 BP 391 EP 400 DI 10.1109/TGRS.2003.817792 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 773XA UT WOS:000188949600013 ER PT J AU Zibordi, G Melin, F Hooker, SB D'Alimonte, D Holbert, B AF Zibordi, G Melin, F Hooker, SB D'Alimonte, D Holbert, B TI An autonomous above-water system for the validation of ocean color radiance data SO IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING LA English DT Article DE above-water radiometry; calibration and validation; ocean color; water-leaving radiance ID ATMOSPHERIC CORRECTION; LEAVING RADIANCES; SEAWIFS; REFLECTANCE; SCATTERING; INSTRUMENT; CALIBRATION; RETRIEVAL; ALGORITHM; PLATFORM AB An operational system for autonomous above-water radiance measurements, called the SeaWiFS Photometer Revision for Incident Surface Measurements (SeaPRISM), was deployed at the Acqua Alta Oceanographic Tower in the northern Adriatic Sea and used for the validation of remote sensing radiometric products in coastal waters. The SeaPRISM data were compared with simultaneous data collected from an independent in-water system for a wide variety of sun elevations along with different atmospheric, seawater, and sea state conditions. The average absolute differences between the above- and in-water determinations of water-leaving radiances (computed linearly) were less than 4.5% in the 412-555-nm spectral interval. A similar comparison for normalized water-leaving radiances showed average absolute differences less than 5.1%. The comparison between normalized water-leaving radiances computed from remote sensing and SeaPRISM matchup data, showed absolute spectral average (linear) differences of 17.0%, 22.1%, and 20.8% for SeaWiFS, MODIS, and MERIS, respectively. The results, in keeping with those produced by independent in-water systems, suggest the feasibility of operational coastal networks of autonomous above-water radiometers deployed on fixed platforms (towers, lighthouses, navigation aids, etc.) to support ocean color validation activities. C1 Commiss European Communities, Joint Res Ctr, Inland & Marine Waters Unit, Inst Environm & Sustainabil, I-21020 Ispra, Italy. NASA, Goddard Space Flight Ctr, Biospher Sci Branch, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Lab Hydrospher Proc, Greenbelt, MD 20771 USA. RP Zibordi, G (reprint author), Commiss European Communities, Joint Res Ctr, Inland & Marine Waters Unit, Inst Environm & Sustainabil, I-21020 Ispra, Italy. RI Hooker, Stanford/E-2162-2012 NR 50 TC 69 Z9 70 U1 2 U2 11 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 0196-2892 J9 IEEE T GEOSCI REMOTE JI IEEE Trans. Geosci. Remote Sensing PD FEB PY 2004 VL 42 IS 2 BP 401 EP 415 DI 10.1109/TGRS.2003.821064 PG 15 WC Geochemistry & Geophysics; Engineering, Electrical & Electronic; Remote Sensing; Imaging Science & Photographic Technology SC Geochemistry & Geophysics; Engineering; Remote Sensing; Imaging Science & Photographic Technology GA 773XA UT WOS:000188949600014 ER PT J AU Min, J Powell, M Bowyer, KW AF Min, J Powell, M Bowyer, KW TI Automated performance evaluation of range image segmentation algorithms SO IEEE TRANSACTIONS ON SYSTEMS MAN AND CYBERNETICS PART B-CYBERNETICS LA English DT Article DE performance evaluation; range image segmentation; region segmentation ID EDGE-DETECTION ALGORITHMS AB Previous performance evaluation of range image segmentation algorithms has depended on manual tuning of algorithm parameters, and has lacked a basis for a test of the significance of differences between algorithms. We present an automated framework for evaluating the performance of range image segmentation algorithms. Automated tuning of algorithm parameters in this framework results in performance as good as that previously obtained with careful manual tuning by the algorithm developers. Use of multiple training and test sets of images provides the basis for a test of the significance of performance differences between algorithms. The framework implementation includes range images, ground truth overlays, program source code, and shell scripts. This framework should a) make it possible to objectively and reliably compare the performance of range image segmentation algorithms; b) allow informed experimental feedback for the design of improved segmentation algorithms. The framework is demonstrated using range images, but in principle it could be used to evaluate region segmentation algorithms for any type of image. C1 Univ Notre Dame, Dept Comp Sci & Engn, Notre Dame, IN 46556 USA. Jet Prop Lab, Mobil Syst Concept Dev Sect, Pasadena, CA 91109 USA. RP Min, J (reprint author), Univ Notre Dame, Dept Comp Sci & Engn, Notre Dame, IN 46556 USA. EM jmin@nd.edu; kwb@cse.nd.edu OI Bowyer, Kevin/0000-0002-7562-4390 NR 21 TC 35 Z9 35 U1 1 U2 5 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 1083-4419 J9 IEEE T SYST MAN CY B JI IEEE Trans. Syst. Man Cybern. Part B-Cybern. PD FEB PY 2004 VL 34 IS 1 BP 263 EP 271 DI 10.1109/TSMCB.2003.811118 PG 9 WC Automation & Control Systems; Computer Science, Artificial Intelligence; Computer Science, Cybernetics SC Automation & Control Systems; Computer Science GA 767QR UT WOS:000188464600024 PM 15369069 ER PT J AU Mayeaux, BM Collins, TE Jerman, GA McDanels, SJ Piascik, RS Russell, RW Shah, SR AF Mayeaux, BM Collins, TE Jerman, GA McDanels, SJ Piascik, RS Russell, RW Shah, SR TI Materials analysis: A key to unlocking the mystery of the Columbia tragedy SO JOM LA English DT Article AB Materials analyses of key forensic evidence helped unlock the mystery of the loss of space shuttle Columbia that disintegrated February 1, 2003 while returning from a 16-day research mission. Following an intensive four-month recovery effort by federal, state, and local emergency management and law officials, Columbia debris was collected, catalogued, and reassembled at the Kennedy Space Center Engineers and scientists from the Materials and Processes (M&P) teamformed by NASA supported Columbia reconstruction efforts, provided factual data through analysis, and conducted experiments to validate the root cause of the accident. Fracture surfaces and thermal effects of selected airframe debris were assessed, and process flows for both nondestructive and destructive sampling and evaluation of debris were developed. The team also assessed left hand (LH) airframe components that were believed to be associated with a structural breach of Columbia. Analytical data collected by the M&P team showed that a significant thermal event occurred at the left wing leading edge in the proximity of LH reinforced carbon carbon (RCC) panels 8 and 9. The analysis also showed exposure to temperatures in excess of 1,649degreesC, which would severely degrade the support structure, tiles, and RCC panel materials. The integrated failure analysis of wing leading edge debris and deposits strongly supported the hypothesis that a breach occurred at LH RCC panel 8. C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. Boeing Co, Seattle, WA 98124 USA. NASA, Langley Res Ctr, Hampton, VA 23665 USA. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. NASA, Kennedy Space Ctr, FL USA. RP Russell, RW (reprint author), United Space Alliance, Kennedy Space Ctr, FL USA. EM steve.mcdanels@NASA.gov; richard.w.russell@usa-spaceops.com NR 10 TC 0 Z9 1 U1 0 U2 1 PU MINERALS METALS MATERIALS SOC PI WARRENDALE PA 184 THORN HILL RD, WARRENDALE, PA 15086 USA SN 1047-4838 J9 JOM-US JI JOM PD FEB PY 2004 VL 56 IS 2 BP 20 EP 30 DI 10.1007/s11837-004-0141-3 PG 11 WC Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Mineralogy; Mining & Mineral Processing SC Materials Science; Metallurgy & Metallurgical Engineering; Mineralogy; Mining & Mineral Processing GA 806AW UT WOS:000220407800003 ER PT J AU Yeheskel, O Nattrass, CE Leisure, RG Jacob, I Bowman, RC AF Yeheskel, O Nattrass, CE Leisure, RG Jacob, I Bowman, RC TI Elastic properties of LaSnxNi5-x compounds SO JOURNAL OF APPLIED PHYSICS LA English DT Article ID LANI5; HYDROGEN; MODULI; DEGRADATION; ULTRASOUND; ISOTHERMS; BEHAVIOR; SOLUBILITY; HYDRIDES; NIOBIUM AB Ultrasonic methods were used to measure the room-temperature elastic moduli of polycrystalline LaSnxNi5-x compounds for 0less than or equal toxless than or equal to0.5. These materials are of great importance for their hydrogen storage properties. The samples, prepared by a hot isostatic pressing method, had near-theoretical densities with calculated porosities ranging from 0 to 1.5%. The porosity-corrected moduli decreased with increasing x. Poisson's ratio was approximately constant at 0.314 for all the compounds. The Debye temperature, calculated from the RT polycrystalline moduli, decreased from 359 to 344 K as x increased from 0 to 0.5. The results were used to calculate the elastic interaction energy of an interstitial hydrogen atom with the strain fields of all the other interstitial hydrogen. This energy was in turn used to calculate the critical temperature below which phase separation occurs in LaMxNi5-xHy compounds (M=Sn or Al). It was found that the critical temperature decreases with increasing x, confirming in a more general way a conclusion drawn for a specific case from earlier thermodynamic measurements. It is suggested that the lowering of the critical temperature plays a role in limiting the width of the plateaus in pressure-composition isotherms for the two-phase regions of these compounds. This suggestion implies a relation between the elastic properties and the maximum hydrogen capacity. (C) 2004 American Institute of Physics. C1 Nucl Res Ctr Negev, IL-84190 Beer Sheva, Israel. Colorado State Univ, Dept Phys, Ft Collins, CO 80523 USA. Ben Gurion Univ Negev, Dept Nucl Engn, IL-84105 Beer Sheva, Israel. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Yeheskel, O (reprint author), Nucl Res Ctr Negev, POB 9001, IL-84190 Beer Sheva, Israel. EM robert.leisure@colostate.edu RI Nattrass, Christine/J-6752-2016 OI Nattrass, Christine/0000-0002-8768-6468 NR 49 TC 13 Z9 13 U1 0 U2 1 PU AMER INST PHYSICS PI MELVILLE PA CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA SN 0021-8979 J9 J APPL PHYS JI J. Appl. Phys. PD FEB 1 PY 2004 VL 95 IS 3 BP 1089 EP 1095 DI 10.1063/1.1636812 PG 7 WC Physics, Applied SC Physics GA 765KN UT WOS:000188281800042 ER PT J AU Rice, JP Butler, JJ Johnson, BC Minnett, PJ Maillet, KA Nightingale, TJ Hook, SJ Abtahi, A Donlon, CJ Barton, IJ AF Rice, JP Butler, JJ Johnson, BC Minnett, PJ Maillet, KA Nightingale, TJ Hook, SJ Abtahi, A Donlon, CJ Barton, IJ TI The Miami2001 infrared radiometer calibration and intercomparison. part I: Laboratory characterization of blackbody targets SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article AB The second calibration and intercomparison of infrared radiometers (Miami2001) was held at the University of Miami's Rosenstiel School of Marine and Atmospheric Science (RSMAS) during May-June 2001. The participants were from several groups involved with the validation of skin sea surface temperatures and land surface temperatures derived from the measurements of imaging radiometers on earth observation satellites. These satellite instruments include those currently on operational satellites and others that will be launched within two years following the workshop. There were two experimental campaigns carried out during the 1-week workshop: a set of measurements made by a variety of ship-based radiometers on board the Research Vessel F. G. Walton Smith in Gulf Stream waters off the eastern coast of Florida, and a set of laboratory measurements of typical external blackbodies used to calibrate these ship-based radiometers. This paper reports on the results obtained from the laboratory characterization on blackbody sources. A companion paper reports on the at-sea measurements. Five blackbody sources were intercompared by measurements of their brightness temperature using the National Institute of Standards and Technology (NIST) Thermal-infrared Transfer Radiometer (TXR). Four of these sources are used for calibration of sea surface temperature radiometers. The fifth was a NIST water bath blackbody used for calibration of the TXR. All blackbodies agreed to better than +/-0.1degreesC at blackbody temperatures near the ambient room temperature. Some of the blackbodies had reduced effective emissivity relative to the NIST water bath blackbody, and hence they began to disagree at blackbody temperatures far enough away (> 15degreesC) from the ambient room temperature. For these, relative effective emissivity values were determined so that corrections can be applied if they are used in conditions of nonlaboratory ambient temperatures. C1 NIST, Opt Technol Div, Gaithersburg, MD 20899 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Miami, Rosenstiel Sch Marine & Atmospher Sci, Div Meteorol & Phys Oceanog, Miami, FL 33149 USA. Rutherford Appleton Lab, Space Sci & Technol Dept, Didcot OX11 0QX, Oxon, England. CALTECH, Jet Prop Lab, Pasadena, CA USA. Commiss European Communities, Joint Res Ctr, Inst Environm & Sustainabil, Inland & Marine Water Unit, I-21020 Ispra, Italy. CSIRO Marine Res, Hobart, Tas, Australia. RP Rice, JP (reprint author), NIST, Opt Technol Div, 100 Bur Dr,Mail Stop 8441, Gaithersburg, MD 20899 USA. EM joe.rice@nist.gov RI Butler, James/D-4188-2013 NR 6 TC 35 Z9 35 U1 1 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 FEB PY 2004 VL 21 IS 2 BP 258 EP 267 DI 10.1175/1520-0426(2004)021<0258:TMIRCA>2.0.CO;2 PG 10 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA 780PT UT WOS:000189391100008 ER PT J AU Barton, IJ Minnett, PJ Maillet, KA Donlon, CJ Hook, SJ Jessup, AT Nightingale, TJ AF Barton, IJ Minnett, PJ Maillet, KA Donlon, CJ Hook, SJ Jessup, AT Nightingale, TJ TI The Miami2001 infrared radiometer calibration and intercomparison. part II: Shipboard results SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article ID EMITTED RADIANCE INTERFEROMETER; SKIN TEMPERATURE-MEASUREMENTS; SEA-SURFACE TEMPERATURE; VALIDATION; ACCURACY; WATERS AB The second calibration and intercomparison of infrared radiometers (Miami2001) was held at the University of Miami's Rosenstiel School of Marine and Atmospheric Science (RSMAS) during a workshop held from May to June 2001. The radiometers targeted in these two campaigns (laboratory-based and at-sea measurements) are those used to validate the skin sea surface temperatures and land surface temperatures derived from the measurements of imaging radiometers on earth observation satellites. These satellite instruments include those on currently operational satellites and others that will be launched within two years following the workshop. The experimental campaigns were completed in one week and included laboratory measurements using blackbody calibration targets characterized by the National Institute of Standards and Technology (NIST), and an intercomparison of the radiometers on a short cruise on board the R/V F. G. Walton Smith in Gulf Stream waters off the eastern coast of Florida. This paper reports on the results obtained from the shipborne measurements. Seven radiometers were mounted alongside each other on the R/V Walton Smith for an intercomparison under seagoing conditions. The ship results confirm that all radiometers are suitable for the validation of land surface temperature, and the majority are able to provide high quality data for the more difficult validation of satellite-derived sea surface temperature, contributing less than 0.1 K to the error budget of the validation. The measurements provided by two prototype instruments developed for ship-of-opportunity use confirmed their potential to provide regular reliable data for satellite-derived SST validation. Four high quality radiometers showed agreements within 0.05 K confirming that these instruments are suitable for detailed studies of the dynamics of air-sea interaction at the ocean surface as well as providing high quality validation data. The data analysis confirms the importance of including an accurate correction for reflected sky radiance when using infrared radiometers to measure SST. The results presented here also show the value of regular intercomparisons of ground-based instruments that are to be used for the validation of satellite-derived data products-products that will be an essential component of future assessments of climate change and variability. C1 Univ Miami, Rosenstiel Sch Marine & Atmospher Sci, Div Meteorol & Phys Oceanog, Miami, FL 33149 USA. CSIRO Marine Res, Hobart, Tas, Australia. Commiss European Communities, Joint Res Ctr, Inst Environm & Sustainabil, Inland & Marine Water Unit, I-21020 Ispra, Italy. CALTECH, Jet Prop Lab, Pasadena, CA USA. Univ Washington, Appl Phys Lab, Seattle, WA 98105 USA. Rutherford Appleton Lab, Space Sci & Technol Dept, Didcot OX11 0QX, Oxon, England. RP Minnett, PJ (reprint author), Univ Miami, Rosenstiel Sch Marine & Atmospher Sci, Div Meteorol & Phys Oceanog, 4600 Rickenbacker Causeway, Miami, FL 33149 USA. EM pminnett@rsmas.miami.edu RI Jessup, Andrew/E-5625-2017 NR 17 TC 36 Z9 38 U1 2 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 FEB PY 2004 VL 21 IS 2 BP 268 EP 283 DI 10.1175/1520-0426(2004)021<0268:TMIRCA>2.0.CO;2 PG 16 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA 780PT UT WOS:000189391100009 ER PT J AU Quilfen, Y Chapron, B Collard, F Vandemark, D AF Quilfen, Y Chapron, B Collard, F Vandemark, D TI Relationship between ERS scatterometer measurement and integrated wind and wave parameters SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article ID CROSS-SECTION; OCEAN; SPEED; DEPENDENCE; STRESS; GROWTH AB Potential effects of environmental parameters such as sea state or atmospheric boundary layer stability on the normalized radar cross section (NRCS) measured by spaceborne sensors have been investigated for a long time. Using neural networks and large high quality collocated datasets, the relation between the European Remote Sensing Satellite (ERS) C-band scatterometer NRCS measurement and integrated sea state parameters (i.e., the mean wave period and significant wave height) measured by buoys is studied. As anticipated, NRCS measurements correlate well with an empirically derived parameter H-alpha/T-beta, revealing the mean bulk relationship between a mean 10-m wind speed and the corresponding sea state development. The correlation and exponents exhibit dependency on the scatterometer incidence angles. A neural model that relates the scatterometer NRCS measurements to these wave spectral integrated parameters and wind speed is also developed. As obtained, the retrieval skill is significantly improved, by comparison with operational empirical models such as CMOD-IFR2 or CMOD4, when including wave effects. As illustrated, systematic biases occur under particular environmental conditions when using the operational scatterometer backscatter model functions. C1 IFREMER, Ctr Brest, Dept Oceanog Spatiale, F-29280 Plouzane, France. BOOST Technol, Plouzane, France. NASA, Goddard Space Flight Ctr, Wallops Flight Facil, Lab Hudrospher Proc, Wallops Isl, VA 23337 USA. RP Quilfen, Y (reprint author), IFREMER, Ctr Brest, Dept Oceanog Spatiale, Technopole Brest Iroise,BP 70, F-29280 Plouzane, France. EM yves.quilfen@ifremer.fr RI Chapron, Bertrand/O-6527-2015; Quilfen, Yves/A-1824-2016 NR 16 TC 14 Z9 14 U1 0 U2 1 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0739-0572 J9 J ATMOS OCEAN TECH JI J. Atmos. Ocean. Technol. PD FEB PY 2004 VL 21 IS 2 BP 368 EP 373 DI 10.1175/1520-0426(2004)021<0368:RBESMA>2.0.CO;2 PG 6 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA 780PT UT WOS:000189391100016 ER PT J AU Chin, TM Ozgokmen, TM Mariano, AJ AF Chin, TM Ozgokmen, TM Mariano, AJ TI Multivariate-spline and scale-specific solution for variational analyses SO JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY LA English DT Article ID DECOMPOSITION; ASSIMILATION AB A recipe for a cubic B-spline-based solution for multivariate variational formulation of a data analysis and assimilation problem is provided. To represent a signal whose smallest wavelength is L, the spline scale must be at most L/2, or approximately the Nyquist wavelength. This spline scale defines the computational grid, which tends to be coarser than the typical grid required for finite-difference discretization and hence offers a significant advantage in computational efficiency. The geostrophy-thin-plate model is introduced and applied to a set of analysis problems to demonstrate the effectiveness of the solution technique. C1 Univ Miami, Rosenstiel Sch Marine & Atmospher Sci, MPO, Miami, FL 33149 USA. CALTECH, Jet Prop Lab, Pasadena, CA USA. RP Ozgokmen, TM (reprint author), Univ Miami, Rosenstiel Sch Marine & Atmospher Sci, MPO, 4600 Rickenbacker Causeway, Miami, FL 33149 USA. EM tozgokmen@rsmas.miami.edu NR 11 TC 1 Z9 1 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 FEB PY 2004 VL 21 IS 2 BP 379 EP 386 DI 10.1175/1520-0426(2004)021<0379:MASSFV>2.0.CO;2 PG 8 WC Engineering, Ocean; Meteorology & Atmospheric Sciences SC Engineering; Meteorology & Atmospheric Sciences GA 780PT UT WOS:000189391100018 ER PT J AU Wu, CC Fry, CD Liu, JY Liou, K Tseng, CL AF Wu, CC Fry, CD Liu, JY Liou, K Tseng, CL TI Annual TEC variation in the equatorial anomaly region during the solar minimum: September 1996-August 1997 SO JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS LA English DT Article DE equatorial ionospheric anomaly; geomagnetic activity; total electron content ID TOTAL ELECTRON-CONTENT; GLOBAL POSITIONING SYSTEM; F-REGION; IONOSPHERE; WIND AB The ionospheric total electron content (TEC) in the equatorial anomaly region is studied by analyzing dual-frequency signals from the global position system (GPS) acquired from a meridional chain of 9 observational sites clustered around Taiwan (21.9degrees-26.2degreesN, 118.4degrees-121.6degrees). This relatively dense GPS chain provides a powerful tool for studying ionospheric TEC in the northern hemispheric equatorial anomaly region with an unprecedented spatial resolution. Specifically, we studied seasonal and geomagnetic effects on the equatorial ionospheric anomaly during the solar minimum period between September 1996 and August 1997. We found that the surveyed data indicated semiannual variations in the magnitude of TEC, I-c, at the anomaly, with maxima in the equinoxes, similar to the semiannual variation of geomagnetic activity. The values of I-c were found to maximize in April, 1997 and minimize in July, 1997. Statistical studies indicate that the monthly values of I-c do not correlate with the planetary K-p magnetic index (r = 0.41) but correlate well with the D-st geomagnetic activity index (r = 0.72). This suggests that variations of TEC are mainly driven by a low-latitude forcing for the surveyed period. The most likely time for I-c to occur was 1400 local time (similar to30%) at 20degreesN geographic latitude (similar to37%). (C) 2004 Published by Elsevier Ltd. C1 Univ Alabama, CSPAR, Huntsville, AL 35899 USA. Explorat Phys Int Inc, Huntsville, AL 35806 USA. Natl Cent Univ, Inst Space Sci, Chungli 32054, Taiwan. Johns Hopkins Univ, Appl Phys Lab, Laurel, MD 20723 USA. Natl Cheng Kung Univ, Satellite Geoinformat Res Ctr, Tainan 70101, Taiwan. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Wu, CC (reprint author), Univ Alabama, CSPAR, Huntsville, AL 35899 USA. EM ccwu@lepvax.gsfc.nasa.gov RI Liu, Jann-Yenq/Q-1668-2015; Liou, Kan/C-2089-2016 OI Liou, Kan/0000-0001-5277-7688 NR 36 TC 48 Z9 57 U1 0 U2 1 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 FEB-MAR PY 2004 VL 66 IS 3-4 BP 199 EP 207 DI 10.1016/j.jastp.2003.09.017 PG 9 WC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences SC Geochemistry & Geophysics; Meteorology & Atmospheric Sciences GA 801UJ UT WOS:000220120500001 ER PT J AU Schubert, SD Suarez, MJ Pegion, PJ Koster, RD Bacmeister, JT AF Schubert, SD Suarez, MJ Pegion, PJ Koster, RD Bacmeister, JT TI Causes of long-term drought in the US Great Plains SO JOURNAL OF CLIMATE LA English DT Article ID SEA-SURFACE TEMPERATURE; GENERAL-CIRCULATION MODELS; STATES SUMMER DROUGHT; CENTRAL UNITED-STATES; NORTH-AMERICA; SOIL-MOISTURE; HEAT WAVES; VARIABILITY; PRECIPITATION; ENSO AB The U.S. Great Plains experienced a number of multiyear droughts during the last century, most notably the droughts of the 1930s and 1950s. This study examines the causes of such droughts using ensembles of long-term (1930-2000) simulations carried out with the NASA Seasonal-to-Interannual Prediction Project (NSIPP-1) atmospheric general circulation model (AGCM) forced with observed sea surface temperatures (SSTs). The results show that the model produces long-term (multiyear) variations in precipitation in the Great Plains region (30degrees-50degreesN, 95degrees-105degreesW) that are similar to those observed. A correlative analysis suggests that the ensemble-mean low-frequency (time scales longer than about 6 yr) rainfall variations in the Great Plains are linked to a pan-Pacific pattern of SST variability that is the leading empirical orthogonal function (EOF) in the low-frequency SST data. The link between the SST and the Great Plains precipitation is confirmed in idealized AGCM simulations, in which the model is forced by the two polarities of the pan-Pacific SST pattern. The idealized simulations further show that it is primarily the tropical part of the SST anomalies that influences the Great Plains. As such, the Great Plains tend to have above-normal precipitation when the tropical Pacific SSTs are above normal, while there is a tendency for drought when the tropical SSTs are cold. The upper-tropospheric response to the pan-Pacific SST EOF shows a global-scale pattern with a strong wave response in the Pacific and a substantial zonally symmetric component in which U. S. Great Plains pluvial (drought) conditions are associated with reduced (enhanced) heights throughout the extratropics. The potential predictability of rainfall in the Great Plains associated with SSTs is rather modest, with about one-third of the total low-frequency rainfall variance being forced by SST anomalies. Further idealized experiments with climatological SST suggest that the remaining low-frequency variance in the Great Plains precipitation is the result of interactions with soil moisture. In particular, simulations with soil moisture feedback show a fivefold increase in the variance in annual Great Plains precipitation compared with simulations in which the soil feedback is excluded. In addition to increasing variance, the interactions with the soil introduce a year-to-year memory in the hydrological cycle. The impact of soil memory is consistent with a red noise process, in which the deep soil is forced by white noise and damped with a time scale of about 1.5 yr. As such, the role of low-frequency SST variability is to introduce a bias to the net forcing on the soil moisture that drives the random process preferentially to either wet or dry conditions. C1 NASA, Goddard Space Flight Ctr, Earth Sci Directorate, Greenbelt, MD 20771 USA. Sci Applicat Int Corp, Beltsville, MD USA. Univ Maryland, Goddard Earth Sci & Technol Ctr, Baltimore, MD 21201 USA. RP NASA, Goddard Space Flight Ctr, Earth Sci Directorate, Code 910-3, Greenbelt, MD 20771 USA. EM schubert@dao.gsfc.nasa.gov RI Pegion, Philip/E-5247-2012; Koster, Randal/F-5881-2012 OI Koster, Randal/0000-0001-6418-6383 NR 44 TC 199 Z9 202 U1 1 U2 42 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0894-8755 EI 1520-0442 J9 J CLIMATE JI J. Clim. PD FEB PY 2004 VL 17 IS 3 BP 485 EP 503 DI 10.1175/1520-0442(2004)017<0485:COLDIT>2.0.CO;2 PG 19 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 772LK UT WOS:000188843200006 ER PT J AU Toracinta, ER Oglesby, RJ Bromwich, DH AF Toracinta, ER Oglesby, RJ Bromwich, DH TI Atmospheric response to modified CLIMAP ocean boundary conditions during the Last Glacial Maximum SO JOURNAL OF CLIMATE LA English DT Article ID SEA-SURFACE TEMPERATURE; SUBTROPICAL NORTH PACIFIC; GENERAL-CIRCULATION MODEL; MODERN ANALOG TECHNIQUE; FINITE-ELEMENT MODEL; ICE-SHEET GROWTH; EQUATORIAL PACIFIC; SOUTHERN OSCILLATION; AGE CLIMATE; NOBLE-GASES AB Global climate simulations are conducted to examine the sensitivity of the Last Glacial Maximum (LGM) climate to prescribed sea surface temperatures (SSTs) that are modified from the Climate: Long-range Investigation, Mapping, and Prediction (CLIMAP) study. Based on the consensus from various LGM proxy data, the SSTs are cooled by 4degreesC uniformly in the Tropics (30degreesN-30degreesS) relative to CLIMAP, and the high-latitude sea ice extent is reduced. Compared to results from a simulation with CLIMAP SSTs, the modified LGM SSTs cause significant opposing changes in the hemispheric and regional-scale atmospheric circulation, which are most pronounced in the winter hemisphere. For instance, there is significant weakening of the midlatitude circulation and reduction of 500-hPa eddy kinetic energy and midlatitude precipitation resulting from the decreased meridional temperature gradient in the modified SST simulation. In contrast, reduced sea ice extent during the boreal winter causes increased regional baroclinicity and intensified atmospheric circulation in the western North Pacific and the North Atlantic. Cooled tropical SSTs also increase the land-ocean temperature contrast, which strengthens the Asian summer monsoon circulation. Both LGM simulations produce enhanced low-level convergence and increased precipitation along the South Pacific convergence zone (SPCZ) relative to present day, despite the cooler LGM climate. The SPCZ orientation and intensity are closely linked to the distribution of South Pacific SSTs. Comparison of surface temperature estimates from land- and ocean-based proxy data with model output suggests that uniform cooling of the tropical SSTs and modification of the high-latitude sea ice extent may be sufficient to accurately simulate the first-order characteristics of the LGM climate. C1 Ohio State Univ, Byrd Polar Res Ctr, Polar Meteorol Grp, Columbus, OH 43210 USA. NASA, George C Marshall Space Flight Ctr, Natl Space Sci & Technol Ctr, Huntsville, AL 35812 USA. Ohio State Univ, Dept Geog, Atmospher Sci Program, Columbus, OH 43210 USA. RP Toracinta, ER (reprint author), Ohio State Univ, Byrd Polar Res Ctr, Polar Meteorol Grp, 1090 Carmack Rd, Columbus, OH 43210 USA. EM toracint@polarmet1.mps.ohio-state.edu RI Bromwich, David/C-9225-2016 NR 95 TC 30 Z9 32 U1 1 U2 3 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 FEB PY 2004 VL 17 IS 3 BP 504 EP 522 PG 19 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 772LK UT WOS:000188843200007 ER PT J AU Kumar, A Yang, FL Goddard, L Schubert, S AF Kumar, A Yang, FL Goddard, L Schubert, S TI Differing trends in the tropical surface temperatures and precipitation over land and oceans SO JOURNAL OF CLIMATE LA English DT Article ID TROPOSPHERIC TEMPERATURE; ATMOSPHERIC RESPONSE; GLOBAL TEMPERATURE; ENSO; CLIMATE; SENSITIVITY; PACIFIC; CIRCULATION; PROJECT; CYCLE AB In the past 50 years, sea surface temperatures (SSTs) in the tropical latitudes have trended toward a warmer ocean state. As a response, tropical land surface temperatures, as well as tropical tropospheric temperatures (as manifested in the variations in the 200-mb tropical heights), have also trended upward. Analysis of trends in the tropical precipitation fields, however, remains problematic because of the scarcity of the observed data over the tropical oceans. Using both observed data and data from atmospheric general circulation model simulations, trends in tropical precipitation over the ocean and land are analyzed. The analysis reveals that in the tropical latitudes over land, the precipitation trend differs from the trend in the surface temperature. Oceanic precipitation has an increasing trend that is consistent with increasing SSTs, whereas over the tropical land regions precipitation decreases. In contrast, land temperatures increase in phase with the trend in SSTs. It is suggested that the combination of increasing surface temperature and decreasing precipitation could produce considerably greater societal consequences compared with the traditionally argued scenario in which both temperature and precipitation increase in response to increasing SSTs. C1 NOAA, Climate Predict Ctr, NWS, NCEP, Camp Springs, MD 20746 USA. NASA, Goddard Space Flight Ctr, Data Assimilat Off, Greenbelt, MD 20771 USA. IRI, Forecast Div, Palisades, NY USA. RP Kumar, A (reprint author), NOAA, Climate Predict Ctr, NWS, NCEP, 5200 Auth Rd,Rm 800, Camp Springs, MD 20746 USA. EM arun.kumar@noaa.gov RI Yang, Fanglin/A-1948-2013 NR 27 TC 62 Z9 62 U1 0 U2 6 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 FEB PY 2004 VL 17 IS 3 BP 653 EP 664 DI 10.1175/1520-0442(2004)017<0653:DTITTS>2.0.CO;2 PG 12 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 772LK UT WOS:000188843200017 ER PT J AU Lau, KM Lee, JY Kim, KM Kang, IS AF Lau, KM Lee, JY Kim, KM Kang, IS TI The North Pacific as a regulator of summertime climate over Eurasia and North America SO JOURNAL OF CLIMATE LA English DT Article; Proceedings Paper CT 6th EAC Workshop CY AUG 04-06, 2002 CL HARBIN, PEOPLES R CHINA SP EAC ID SEA-SURFACE TEMPERATURE; GENERAL-CIRCULATION MODEL; UNITED-STATES; SST ANOMALIES; INTERANNUAL VARIABILITY; ENSO TELECONNECTIONS; ATMOSPHERIC BRIDGE; SCALE CIRCULATION; PRECIPITATION; MONSOON AB The role of the North Pacific as a regulator of boreal summer climate over Eurasia and North America is investigated using observational data. Two summertime interannual climate modes associated with sea surface temperature (SST) variability in the North Pacific are identified. The first mode shows an elongated zone of warm ( cold) SST anomalies in the central North Pacific along 40degreesN, with temporal variability significantly correlated with El Nino during the preceding spring, but its subsequent evolution is quite different from El Nino. The second mode exhibits a seesaw SST variation between the northern and southern North Pacific and is independent of El Nino. Both modes are linked to coherent SST anomalies over the North Atlantic, suggesting the presence of an "atmospheric bridge'' linking the two extratropical oceans. Using the principal component of the most dominant mode as the North Pacific index (NPI), composite analyses show that the positive ( negative) phase of NPI features a warm ( cold) North Pacific associated with the formation of contemporaneous low-level stationary anticyclones ( cyclones) over the North Pacific and North Atlantic, respectively. The anticyclones ( cyclones) are linked by quasi-zonally symmetric circulation anomalies in the middle to upper troposphere spanning Eurasia and North America, accompanied by a poleward (equatorward) shift of the subtropical jet and storm tracks. Associated with the positive ( negative) phase of NPI, are hot/dry (cool/wet) summers over Japan, Korea, and eastern-central China, which are linked to hot/dry (cool/ wet) conditions in the Pacific Northwest, western Canada, the U. S. northern Great Plains, and the Midwest. Cumulative probability computed from pentad temperature and rainfall data show that the odds of occurrence of extreme events are impacted consistently with the mean climate shift during opposite phases of the NPI. The possible roles of air-sea interaction and transient-mean flow interaction in exciting and sustaining the climate modes are discussed. C1 NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. Seoul Natl Univ, Sch Earth & Environm Sci, Seoul, South Korea. Sci Syst & Applicat Inc, Lanham, MD USA. RP Lau, KM (reprint author), NASA, Goddard Space Flight Ctr, Atmospheres Lab, Code 910,Bldg 33,Rm C121, Greenbelt, MD 20771 USA. EM lau@climate.gsfc.nasa.gov RI Lee, June-Yi/D-5752-2012; Kim, Kyu-Myong/G-5398-2014; Lau, William /E-1510-2012; 안, 민섭/D-9972-2015 OI Lau, William /0000-0002-3587-3691; NR 47 TC 59 Z9 68 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 FEB PY 2004 VL 17 IS 4 BP 819 EP 833 DI 10.1175/1520-0442(2004)017<0819:TNPAAR>2.0.CO;2 PG 15 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 773RC UT WOS:000188935700010 ER PT J AU Woodcraft, AL Sudiwala, RV Wakui, E Paine, C AF Woodcraft, AL Sudiwala, RV Wakui, E Paine, C TI Hopping conduction in NTD germanium: Comparison between measurement and theory SO JOURNAL OF LOW TEMPERATURE PHYSICS LA English DT Article DE germanium; ADR; NTD ID COULOMB GAP; SEMICONDUCTOR BOLOMETERS; DOPED SILICON; TEMPERATURE; STATES; FILMS AB We present precise measurements of the resistance-temperature variation of several samples of neutron transmutation doped (NTD) germanium, at temperatures from 70 mK to 1 K. This material is widely used for sensitive thermometry, often as the thermistor element in bolometers and microcalorimeters. It is also used in investigations of the low temperature conductivity of highly doped semiconductors. The resistance, R, is expected to follow the variable range hopping equation R(T)=R-o exp(T-0/T)(p), where T is temperature and R-o and T-o are material parameters. A value of p=0.5 is predicted theoretically, and generally seems to be in good agreement with experimental measurements. However, some theories and numerical calculations predict different values of p. Knowledge of the correct resistance-temperature relationship is important for the accurate calibration of thermometers, and also delivers insight into the basic physics involved. Most experimental measurements on germanium have not had sufficient precision to distinguish between the different predicted values of p. We show that such measurements are nevertheless possible. Our results are all in excellent agreement with the expected variable range hopping behaviour. However, the values of p appear to vary with doping density, in disagreement with most theories. We have considered and rejected both random and systematic errors as an explanation for the observed behaviour, and have confirmed the results by making measurements in two different systems with independent readout systems and temperature calibrations. The situation is complicated by the possibility of temperature dependence of R-o. The expected form is R-o (T) proportional to T-q; however, there is considerable disagreement over the predicted value of q. We show that in general it is not possible to determine both p and q from resistance measurements. However, our results can only be explained if either or both of q and p vary from sample to sample. Such behaviour is not generally expected. We show that neglecting the q term can lead to serious errors when calibrating thermometers. However, the degeneracy between p and q means that for a calibration the q term can be neglected, and good fits obtained if p is allowed to vary. Our results suggest that further theoretical work is required in this area, backed up by more comprehensive measurements. C1 Cardiff Univ, Dept Phys & Astron, Cardiff CF24 3YB, S Glam, Wales. Univ London Queen Mary & Westfield Coll, Dept Phys, London E1 4NS, England. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Woodcraft, AL (reprint author), Cardiff Univ, Dept Phys & Astron, POB 913, Cardiff CF24 3YB, S Glam, Wales. EM Adam.Woodcraft@astro.cf.ac.uk NR 36 TC 14 Z9 14 U1 1 U2 5 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0022-2291 J9 J LOW TEMP PHYS JI J. Low Temp. Phys. PD FEB PY 2004 VL 134 IS 3-4 BP 925 EP 944 DI 10.1023/B:JOLT.0000013209.08494.01 PG 20 WC Physics, Applied; Physics, Condensed Matter SC Physics GA 767CW UT WOS:000188423500005 ER PT J AU Tang, T Han, S Jin, W Liu, XL Li, C Zhang, DH Zhou, CW Chen, B Han, J Meyyapan, M AF Tang, T Han, S Jin, W Liu, XL Li, C Zhang, DH Zhou, CW Chen, B Han, J Meyyapan, M TI Synthesis and characterization of single-crystal indium nitride nanowires SO JOURNAL OF MATERIALS RESEARCH LA English DT Article ID GROWTH; INN; TRANSPORT; FILMS AB InN nanowires were synthesized and characterized using a variety of techniques. A two-zone chemical vapor deposition technique was used to operate the vapor generation and the nanowire growth at differential temperatures, leading to high-quality single-crystal line nanowires and growth rates as high as 4-10 mum/h. Precise diameter control was achieved by using monodispersed gold clusters as the catalyst. Photoluminescence and Raman studies have been carried out for the InN nanowires at room temperature. Devices consisting of single nanowires have been fabricated to explore their electronic transport properties. The temperature dependence of the conductance revealed thermal emission as the dominating transport mechanism. C1 Univ So Calif, Dept Elect Engn Electrophys, Los Angeles, CA 90089 USA. NASA, Ames Res Ctr, Eloret Corp, Moffett Field, CA 94035 USA. RP Zhou, CW (reprint author), Univ So Calif, Dept Elect Engn Electrophys, Los Angeles, CA 90089 USA. EM chongwuz@usc.edu RI Tang, Tao/C-8123-2011; Zhou, Chongwu/F-7483-2010 NR 13 TC 72 Z9 73 U1 1 U2 22 PU MATERIALS RESEARCH SOCIETY PI WARRENDALE PA 506 KEYSTONE DR, WARRENDALE, PA 15086 USA SN 0884-2914 J9 J MATER RES JI J. Mater. Res. PD FEB PY 2004 VL 19 IS 2 BP 423 EP 426 DI 10.1557/jmr.2004.19.2.423 PG 4 WC Materials Science, Multidisciplinary SC Materials Science GA 833DI UT WOS:000222316200005 ER PT J AU Morgan, B Waits, CM Krizmanic, J Ghodssi, R AF Morgan, B Waits, CM Krizmanic, J Ghodssi, R TI Development of a deep silicon phase Fresnel lens using gray-scale lithography and deep reactive ion etching SO JOURNAL OF MICROELECTROMECHANICAL SYSTEMS LA English DT Article DE deep-reactive ion etching (DRIE); gray-scale lithography; phase Fresnel lens (PFL); three-dimensional (3-D) structures ID ZONE PLATES; EFFICIENCY; FABRICATION; MICROLENS AB We report the first fabrication and development of a deep phase Fresnel lens (PFL) in silicon through the use of gray-scale lithography and deep-reactive ion etching (DRIE). A Gaussian tail approximation is introduced as a method of predicting the height of photoresist gray levels given the relative amount of transmitted light through a gray-scale optical mask. Device mask design is accomplished through command-line scripting in a CAD tool to precisely define the millions of pixels required to generate the appropriate profile in photoresist. Etch selectivity during DRIE pattern transfer is accurately controlled to produce the desired scaling factor between the photoreist and silicon profiles. As a demonstration of this technology, a 1.6-mm diameter PFL is etched 43 mum into silicon with each grating profile designed to focus 8.4 keV photons a distance of 118 m. C1 Univ Maryland, Dept Elect & Comp Engn, College Pk, MD 20742 USA. Univ Maryland, Syst Res Inst, College Pk, MD 20742 USA. NASA, Goddard Space Flight Ctr, Univ Space Res Assoc, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Morgan, B (reprint author), Univ Maryland, Dept Elect & Comp Engn, College Pk, MD 20742 USA. EM bmorgan2@glue.umd.edu; cmwaits@glue.umd.edu; jfk@cosmicra.gsgc.nasa.gov; ghodssi@eng.umd.edu NR 27 TC 71 Z9 71 U1 2 U2 8 PU IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC PI PISCATAWAY PA 445 HOES LANE, PISCATAWAY, NJ 08855 USA SN 1057-7157 J9 J MICROELECTROMECH S JI J. Microelectromech. Syst. PD FEB PY 2004 VL 13 IS 1 BP 113 EP 120 DI 10.1109/JMEMS.2003.823220 PG 8 WC Engineering, Electrical & Electronic; Nanoscience & Nanotechnology; Instruments & Instrumentation; Physics, Applied SC Engineering; Science & Technology - Other Topics; Instruments & Instrumentation; Physics GA 780BG UT WOS:000189350800012 ER PT J AU Miller, AJ Chai, F Chiba, S Moisan, JR Neilson, DJ AF Miller, AJ Chai, F Chiba, S Moisan, JR Neilson, DJ TI Decadal-scale climate and ecosystem interactions in the North Pacific Ocean SO JOURNAL OF OCEANOGRAPHY LA English DT Review DE Pacific Ocean; decadal variability; ecosystems; climate forcing; feedbacks ID SEA-SURFACE TEMPERATURE; SUB-ARCTIC PACIFIC; CALIFORNIA CURRENT SYSTEM; EASTERN BERING-SEA; PHYSICAL-BIOLOGICAL MODEL; GENERAL-CIRCULATION MODEL; HEMISPHERE SST FIELD; SANTA-BARBARA BASIN; WEATHER STATION-P; EQUATORIAL PACIFIC AB Decadal-scale climate variations in the Pacific Ocean wield a strong influence on the oceanic ecosystem. Two dominant patterns of large-scale SST variability and one dominant pattern of large-scale thermocline variability can be explained as a forced oceanic response to large-scale changes in the Aleutian Low. The physical mechanisms that generate this decadal variability are still unclear, but stochastic atmospheric forcing of the ocean combined with atmospheric teleconnections from the tropics to the midlatitudes and some weak ocean-atmosphere feedbacks processes are the most plausible explanation. These observed physical variations organize the oceanic ecosystem response through large-scale basin-wide forcings that exert distinct local influences through many different processes. The regional ecosystem impacts of these local processes are discussed for the Tropical Pacific, the Central North Pacific, the Kuroshio-Oyashio Extension, the Bering Sea, the Gulf of Alaska, and the California Current System regions in the context of the observed decadal climate variability. The physical ocean-atmosphere system and the oceanic ecosystem interact through many different processes. These include physical forcing of the ecosystem by changes in solar fluxes, ocean temperature, horizontal current advection, vertical mixing and upwelling, freshwater fluxes, and sea ice. These also include oceanic ecosystem forcing of the climate by attenuation of solar energy by phytoplankton absorption and atmospheric aerosol production by phytoplankton DMS fluxes. A more complete understanding of the complicated feedback processes controlling decadal variability, ocean ecosystems, and biogeochemical cycling requires a concerted and organized long-term observational and modeling effort. C1 Univ Calif San Diego, Scripps Inst Oceanog, La Jolla, CA 92093 USA. Univ Maine, Sch Marine Sci, Orono, ME 04469 USA. Japan Marine Sci & Technol Ctr, Frontier Res Syst Global Change, Yokohama, Kanagawa 2360001, Japan. NASA, Goddard Space Flight Ctr, Wallops Flight Facil, Wallops Isl, VA 23337 USA. RP Univ Calif San Diego, Scripps Inst Oceanog, La Jolla, CA 92093 USA. EM ajmiller@ucsd.edu RI Moisan, John/B-8762-2016 OI Moisan, John/0000-0002-8078-8939 NR 240 TC 63 Z9 66 U1 5 U2 31 PU SPRINGER PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0916-8370 EI 1573-868X J9 J OCEANOGR JI J. Oceanogr. PD FEB PY 2004 VL 60 IS 1 BP 163 EP 188 DI 10.1023/B:JOCE.0000038325.36306.95 PG 26 WC Oceanography SC Oceanography GA 765BW UT WOS:000188248100012 ER PT J AU Bayard, DS Jelliffe, RW AF Bayard, DS Jelliffe, RW TI A Bayesian approach to tracking patients having changing pharmacokinetic parameters SO JOURNAL OF PHARMACOKINETICS AND PHARMACODYNAMICS LA English DT Article DE health sciences; estimation; filtering; Markov Chain; decision support systems; pharmacokinetics; therapeutic drug monitoring; interactive multiple model; time-varying parameters ID SYSTEMS AB This paper considers the updating of Bayesian posterior densities for pharmacokinetic models associated with patients having changing parameter values. For estimation purposes it is proposed to use the Interacting Multiple Model (IMM) estimation algorithm, which is currently a popular algorithm in the aerospace community for tracking maneuvering targets. The IMM algorithm is described, and compared to the multiple model (MM) and Maximum A-Posteriori (MAP) Bayesian estimation methods, which are presently used for posterior updating when pharmacokinetic parameters do not change. Both the MM and MAP Bayesian estimation methods are used in their sequential forms, to facilitate tracking of changing parameters. Results indicate that the IMM algorithm is well suited for tracking time-varying pharmacokinetic parameters in acutely ill and unstable patients, incurring only about half of the integrated error compared to the sequential MM and MAP methods on the same example. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ So Calif, Sch Med, Lab Appl Pharmacokinet, Los Angeles, CA 90033 USA. RP Bayard, DS (reprint author), CALTECH, Jet Prop Lab, Mial Stop 198-326,4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM david.bayard@jpl.nasa.gov NR 17 TC 25 Z9 26 U1 0 U2 1 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 1567-567X J9 J PHARMACOKINET PHAR JI J. Pharmacokinet. Pharmacodyn. PD FEB PY 2004 VL 31 IS 1 BP 75 EP 107 DI 10.1023/B:JOPA.0000029490.76908.0c PG 33 WC Pharmacology & Pharmacy SC Pharmacology & Pharmacy GA 824TS UT WOS:000221710200005 PM 15346853 ER PT J AU Behrenfeld, MJ Prasil, O Babin, M Bruyant, F AF Behrenfeld, MJ Prasil, O Babin, M Bruyant, F TI In search of a physiological basis for covariations in light-limited and light-saturated photosynthesis SO JOURNAL OF PHYCOLOGY LA English DT Review DE photosynthesis-irradiance relationships; productivity; phytoplankton; physiology ID COASTAL MARINE-PHYTOPLANKTON; THALASSIOSIRA-WEISSFLOGII BACILLARIOPHYCEAE; NITRATE REDUCTASE-ACTIVITY; ALGA SELENASTRUM-MINUTUM; EQUATORIAL PACIFIC; DIEL PERIODICITY; PHOTOSYSTEM-II; ELECTRON-TRANSPORT; CIRCADIAN-RHYTHM; CHLAMYDOMONAS-REINHARDTII AB The photosynthesis-irradiance (PE) relationship links indices of phytoplankton biomass (e.g. chl) to rates of primary production. The PE curve can be characterized by two variables: the light-limited slope (alpha(b)) and the light-saturated rate (P-max(b)) of photosynthesis. Variability in PE curves can be separated into two categories: that associated with changes in the light saturation index, E-k (=P-max(b)/alpha(b)) and that associated with parallel changes in alpha(b)and P-max(b) (i.e. no change in E-k). The former group we refer to as "E-k-dependent" variability, and it results predominantly from photoacclimation (i.e. physiological adjustments in response to changing light). The latter group we refer to as "E-k-independent" variability, and its physiological basis is unknown. Here, we provide the first review of the sporadic field and laboratory reports of E-k-independent variability, and then from a stepwise analysis of potential mechanisms we propose that this important yet largely neglected phenomenon results from growth rate-dependent variability in the metabolic processing of photosynthetically generated reductants (and generally not from changes in the oxygen-evolving PSII complexes). Specifically, we suggest that as growth rates decrease (e.g. due to nutrient stress), reductants are increasingly used for simple ATP generation through a fast (<1s) respiratory pathway that skips the carbon reduction cycle altogether and is undetected by standard PE methodologies. The proposed mechanism is consistent with the field and laboratory data and involves a simple new "twist" on established metabolic pathways. Our conclusions emphasize that simple reductants, not reduced carbon compounds, are the central currency of photoautotrophs. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ S Bohemia, Trebon Inst Phys Biol 37981, AVCR, Inst Microbiol, Nove Hrady, Czech Republic. Univ Paris 06, CNRS Quai Darse, Lab Oceanog Villefranche, Villefranche Sur Mer, France. Dalhousie Univ, Dept Oceanog, Halifax, NS B3H 4J1, Canada. RP Behrenfeld, MJ (reprint author), NASA, Goddard Space Flight Ctr, Code 970,Bldg 22, Greenbelt, MD 20771 USA. EM mjb@neptune.gsfc.nasa.gov RI Prasil, Ondrej/H-2454-2014 OI Prasil, Ondrej/0000-0002-0012-4359 NR 116 TC 133 Z9 135 U1 5 U2 58 PU BLACKWELL PUBLISHING INC PI MALDEN PA 350 MAIN ST, MALDEN, MA 02148 USA SN 0022-3646 J9 J PHYCOL JI J. Phycol. PD FEB PY 2004 VL 40 IS 1 BP 4 EP 25 DI 10.1046/j.1529-8817.2004.03083.x PG 22 WC Plant Sciences; Marine & Freshwater Biology SC Plant Sciences; Marine & Freshwater Biology GA 772WJ UT WOS:000188864700002 ER PT J AU Drouin, BJ AF Drouin, BJ TI Temperature dependent pressure-induced lineshape of the HCl J=1 <- 0 rotational transition in nitrogen and oxygen SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Article DE hydrogen chloride; linewidths; pressure broadening; atmospheric spectra ID N-2 AB The pressure-induced broadening and shift of the lowest rotational transition of hydrogen chloride have been measured in both nitrogen and oxygen as a function of temperature. This work improves the accuracy of the broadening parameter and provides the first experimental parameterization of the pressure shift. The HCl air broadened half-width is determined to < 4.1% across the temperature range of the stratosphere and upper troposphere. (C) 2003 Elsevier Ltd. All rights reserved. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Drouin, BJ (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 10 TC 17 Z9 17 U1 0 U2 2 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 FEB 1 PY 2004 VL 83 IS 3-4 BP 321 EP 331 DI 10.1016/S0022-4073(02)00360-6 PG 11 WC Optics; Spectroscopy SC Optics; Spectroscopy GA 743MY UT WOS:000186577500007 ER PT J AU Sun, WB Loeb, NG Fu, Q AF Sun, WB Loeb, NG Fu, Q TI Light scattering by coated sphere immersed in absorbing medium: a comparison between the FDTD and analytic solutions SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Article DE light scattering; coated sphere; absorbing medium ID PERFECTLY MATCHED LAYER; TIME-DOMAIN SOLUTION; BOUNDARY-CONDITION; MIE-SCATTERING; ELECTROMAGNETIC-WAVES; HOST MEDIUM; PARTICLES; ABSORPTION; EXTINCTION AB A recently developed finite-difference time domain scheme is examined using the exact analytic solutions for light scattering by a coated sphere immersed in an absorbing medium. The relative differences are less than 1% in the extinction, scattering, and absorption efficiencies and less than 5% in the scattering phase functions. The definition of apparent single-scattering properties is also discussed. (C) 2003 Elsevier Ltd. All rights reserved. C1 Hampton Univ, Ctr Atmospher Sci, Hampton, VA 23668 USA. Univ Washington, Dept Atmospher Sci, Seattle, WA 98195 USA. RP Sun, WB (reprint author), NASA Langley Res Ctr, Mail Stop 420,21 Langley Blvd, Hampton, VA 23681 USA. NR 26 TC 14 Z9 15 U1 0 U2 6 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 FEB 1 PY 2004 VL 83 IS 3-4 BP 483 EP 492 DI 10.1016/S0022-4073(03)00101-8 PG 10 WC Optics; Spectroscopy SC Optics; Spectroscopy GA 743MY UT WOS:000186577500018 ER PT J AU Tanaka, T Wang, MH AF Tanaka, T Wang, MH TI Solution of radiative transfer in anisotropic plane-parallel atmosphere SO JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER LA English DT Article DE solution of Chandrasekhar integral equation; radiative transfer process; anisotropic atmosphere; iterative integration; satellite remotesensing; inversion problem ID SCATTERING AB We solve the radiative transfer problem analytically in the anisotropic, plane-parallel atmosphere. Chandrasekhar formalized the radiative transfer process as a simultaneous, two-variable, non-linear, integral equation and obtained the analytical solution of the second approximation for the isotropic plane-parallel atmosphere. We obtain the second approximation for the anisotropic atmosphere, by integrating the first approximation multiplied by weighting functions which are products of the scattering phase functions. We truncate the second approximation and obtain the radiance at the top of the atmosphere as a quadratic equation with a logarithmic term in the optical thickness. We evaluate the second approximation of the radiance at the top of the atmosphere for Rayleigh scattering and the maritime aerosol atmosphere and compare them with both the exact solution and the single scattering approximation. (C) 2003 Elsevier Ltd. All rights reserved. C1 Natl Space Dev Agcy Japan, Earth Observat Res Ctr, Chuou Ku, Tokyo, Japan. Univ Maryland Baltimore Cty, NASA, Goddard Space Ctr, Greenbelt, MD 20771 USA. RP Tanaka, T (reprint author), Natl Space Dev Agcy Japan, Earth Observat Res Ctr, Chuou Ku, 1-8-10 Harumi, Tokyo, Japan. RI Wang, Menghua/F-5631-2010 OI Wang, Menghua/0000-0001-7019-3125 NR 7 TC 4 Z9 4 U1 0 U2 1 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0022-4073 J9 J QUANT SPECTROSC RA JI J. Quant. Spectrosc. Radiat. Transf. PD FEB 1 PY 2004 VL 83 IS 3-4 BP 555 EP 577 DI 10.1016/S0022-4073(03)00105-5 PG 23 WC Optics; Spectroscopy SC Optics; Spectroscopy GA 743MY UT WOS:000186577500022 ER PT J AU Reeder, JR Glaessgen, EH AF Reeder, J. R. Glaessgen, E. H. TI Debonding of Stitched Composite Joints Under Static and Fatigue Loading SO JOURNAL OF REINFORCED PLASTICS AND COMPOSITES LA English DT Article DE polymer composite; stitched; joint; fatigue; propagation; failure mechanics; resin film infusion AB An experimental study was conducted to examine the effects of stitches on the static and fatigue failure of two different single lap joint configurations. To monitor damage growth, Xrays were taken periodically during the fatigue tests. The study showed that a 2 fold increase in static strength due to stitching. A similar increase was found in fatigue strength for a given fatigue life. Additionally, stitching significantly changed the pattern of damage growth. C1 [Reeder, J. R.; Glaessgen, E. H.] NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Reeder, JR (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 9 TC 5 Z9 5 U1 0 U2 0 PU SAGE PUBLICATIONS LTD PI LONDON PA 1 OLIVERS YARD, 55 CITY ROAD, LONDON EC1Y 1SP, ENGLAND SN 0731-6844 EI 1530-7964 J9 J REINF PLAST COMP JI J. Reinf. Plast. Compos. PD FEB PY 2004 VL 23 IS 3 BP 249 EP 263 DI 10.1177/0731684404030661 PG 15 WC Materials Science, Composites; Polymer Science SC Materials Science; Polymer Science GA V30PG UT WOS:000208827300002 ER PT J AU Wang, ZJ Liu, Y AF Wang, ZJ Liu, Y TI Spectral (finite) volume method for conservation laws on unstructured grids III: One dimensional systems and partition optimization SO JOURNAL OF SCIENTIFIC COMPUTING LA English DT Article DE high-order; unstructured grid; spectral volume; system of conservation laws; Euler equations ID ESSENTIALLY NONOSCILLATORY SCHEMES; ELEMENT METHOD; IMPLEMENTATION; INTERPOLATION; MESHES AB In this paper, the third in a series, the Spectral Volume (SV) method is extended to one-dimensional systems-the quasi-1D Euler equations. In addition, several new partitions are identified which optimize a certain form of the Lebesgue constant, and the performance of these partitions is assessed with the linear wave equation. A major focus of this paper is to verify that the SV method is capable of achieving high-order accuracy for hyperbolic systems of conservation laws. Both steady state and time accurate problems are used to demonstrate the overall capability of the SV method. C1 Michigan State Univ, E Lansing, MI 48824 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Wang, ZJ (reprint author), Michigan State Univ, 2555 Engn Bldg, E Lansing, MI 48824 USA. EM zjw@egr.msu.edu; liu@nas.nasa.gov RI Wang, Z.J./A-9628-2010 OI Wang, Z.J./0000-0002-6203-6303 NR 20 TC 86 Z9 88 U1 0 U2 4 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0885-7474 J9 J SCI COMPUT JI J. Sci. Comput. PD FEB PY 2004 VL 20 IS 1 BP 137 EP 157 DI 10.1023/A:1025896119548 PG 21 WC Mathematics, Applied SC Mathematics GA 772MX UT WOS:000188846800006 ER PT J AU Marcus, SL de Viron, O Dickey, JO AF Marcus, SL de Viron, O Dickey, JO TI Atmospheric contributions to earth nutation: Geodetic constraints and limitations of the torque approach SO JOURNAL OF THE ATMOSPHERIC SCIENCES LA English DT Article ID ANGULAR-MOMENTUM; PRECESSION; PRESSURE AB Atmospheric motions in the retrograde diurnal (S-1) band are of interest to a wide community of researchers in earth dynamics and geodesy, due to their potential contribution to the low-frequency motions of the rotation axis known as nutations. Previous studies of these effects have noted an order-of-magnitude discrepancy between estimates of atmosphere-induced nutation based on the torque and angular momentum approaches. In this note, angular momentum budgets computed from NCEP reanalysis data are examined in order to isolate the reasons for this discrepancy, and associated constraints on the atmospheric response to solar diurnal forcing are considered. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Observ Royal Belgique, B-1180 Brussels, Belgium. RP Marcus, SL (reprint author), CALTECH, Jet Prop Lab, Mail Stop 238-332,4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM steven.marcus@jpl.nasa.gov RI de Viron, Olivier/N-6647-2014 OI de Viron, Olivier/0000-0003-3112-9686 NR 9 TC 7 Z9 7 U1 0 U2 2 PU AMER METEOROLOGICAL SOC PI BOSTON PA 45 BEACON ST, BOSTON, MA 02108-3693 USA SN 0022-4928 J9 J ATMOS SCI JI J. Atmos. Sci. PD FEB PY 2004 VL 61 IS 3 BP 352 EP 356 DI 10.1175/1520-0469(2004)061<0352:ACTENG>2.0.CO;2 PG 5 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 770DD UT WOS:000188707200008 ER PT J AU Majchrzak, A Cooper, LP Neece, OE AF Majchrzak, A Cooper, LP Neece, OE TI Knowledge reuse for innovation SO MANAGEMENT SCIENCE LA English DT Article DE knowledge management; knowledge transfer; innovation ID MANAGEMENT; TECHNOLOGY; WORK; ORGANIZATIONS; CAPABILITIES; SYSTEMS; FIRMS AB This study was conducted to better understand the knowledge reuse process when radical innovation (e.g., experiments to prepare for human exploration of Mars) is expected. The research involved detailing the knowledge reuse process in six case studies varying in degree of innovation. Across the six cases, a six-stage reuse-for-innovation process was identified consisting of three major actions: reconceptualize the problem and approach, including deciding to search for others' ideas to reuse; search-and-evaluate others' ideas to reuse; and develop the selected idea. Findings include (1) the need for an insurmountable gap in performance to stimulate the decision to reuse others' knowledge; (2) the critical importance of an adapter to bridge the idea source and recipient; (3) three layers of search-and-evaluate activities in which the first layer of scanning to find ideas to reuse and the last layer of detailed analysis of ideas are bridged by a layer of brief evaluations of ideas assessing the presence (or absence) of targeted information about each idea; and (4) the differential use of metaknowledge about each idea to facilitate proceeding through each search-and-evaluate layer. In addition, reusers in the more (versus less) innovative cases redefined problems at the outset in nontraditional ways using analogies and extensions, rather than accepting the preexisting problem definition; used a substantially broader search strategy with a greater variety of search methods; and worked more closely with adapters during the latter stages of the reuse process. C1 Univ So Calif, Marshall Sch Business, Dept Informat & Operat Management, Los Angeles, CA 90089 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Claremont Grad Sch, Claremont, CA 91711 USA. RP Majchrzak, A (reprint author), Univ So Calif, Marshall Sch Business, Dept Informat & Operat Management, Los Angeles, CA 90089 USA. EM majchrza@usc.edu; lynne.p.cooper@jpl.nasa.gov; olivia.neece@earthlink.net NR 47 TC 155 Z9 158 U1 13 U2 71 PU INST OPERATIONS RESEARCH MANAGEMENT SCIENCES PI LINTHICUM HTS PA 901 ELKRIDGE LANDING RD, STE 400, LINTHICUM HTS, MD 21090-2909 USA SN 0025-1909 J9 MANAGE SCI JI Manage. Sci. PD FEB PY 2004 VL 50 IS 2 BP 174 EP 188 DI 10.1287/mnsc.1030.0116 PG 15 WC Management; Operations Research & Management Science SC Business & Economics; Operations Research & Management Science GA 779KB UT WOS:000189292900004 ER PT J AU Claustre, H Hooker, SB Van Heukelem, L Berthon, JF Barlow, R Ras, J Sessions, H Targa, C Thomas, CS van der Linde, D Marty, JC AF Claustre, H Hooker, SB Van Heukelem, L Berthon, JF Barlow, R Ras, J Sessions, H Targa, C Thomas, CS van der Linde, D Marty, JC TI An intercomparison of HPLC phytoplankton pigment methods using in situ samples: application to remote sensing and database activities SO MARINE CHEMISTRY LA English DT Article DE pigments; HPLC; phytoplankton; database; methods ID PERFORMANCE LIQUID-CHROMATOGRAPHY; DIVINYL CHLOROPHYLL-A; MARINE-PHYTOPLANKTON; EUPHOTIC ZONE; CAROTENOIDS; OCEAN; DISTRIBUTIONS; FLUORESCENCE; VARIABILITY; ZEAXANTHIN AB Whether for biogeochemical studies or ocean color validation activities, high-performance liquid chromatography (HPLC) is an established reference technique for the analysis of chlorophyll a and associated phytoplankton pigments. The results of an intercomparison exercise of HPLC pigment determination, performed for the first time on natural samples and involving four laboratories (each using a different HPLC procedure), are used to address three main objectives: (a) estimate (and explain) the level of agreement or discrepancy in the methods used, (b) establish whether or not the accuracy requirements for ocean color validation activities can be met, and (c) establish how higher order associations in individual pigments (i.e., sums and ratios) influence the uncertainty budget while also determining how this information can be used to minimize the variance within larger pigment databases. The round-robin test samples (11 different samples received in duplicate by each laboratory) covered a range of total chlorophyll a concentration, [TChl a], representative of open ocean conditions from 0.045 mg m(-3), typical of the highly oligotrophic surface waters of the Ionian Sea, to 2.2 mg m(-3), characteristic of the upwelling regime off Morocco. Despite the diversity in trophic conditions and HPLC methods, the agreement between laboratories, defined here as the absolute percent difference (APD), was approximately 7.0% for [TChl a], which is well within the 25% accuracy objective for remote sensing validation purposes. For other pigments (mainly chemotaxinomic carotenoids), the agreement between methods was 21.5% on average (ranging from 11.5% for fucoxanthin to 32.5% for peridinin), and inversely depended on pigment concentration (with large disagreements for pigments close to the detection limits). It is shown that better agreement between methods can be achieved if some simple procedures are employed: (a) disregarding results less than the effective limit of quantitation (LOQ, an alternative to the method detection limit, MDL), (b) standardizing the manner in which the concentration of pigment standards are determined, and (c) accurately accounting for divinyl chlorophyll a when computing [TChl a] for those methods which do not chromatographically separate it from monovinyl chlorophyll a. The use of these quality-assurance procedures improved the agreement between methods, with average APD values dropping from 7.0% to 5.5% for [TChl a] and from 21.5% to 13.9% for the principal carotenoids. Additionally, it is shown that subsequent grouping of individual pigment concentrations into sums and ratios significantly reduced the variance and, thus, improved the agreement between laboratories. This grouping, therefore, provides a simple mechanism for decreasing the variance within databases composed of merged data from different origins. Among the recommendations for improving database consistency in the future, it is suggested that submissions to a database should include the relevant information related to the limit of detection for the HPLC method. (C) 2003 Elsevier B.V. All rights reserved. C1 Lab Oceanog Villefranche, F-06238 Villefranche Sur Mer, France. Marine & Coastal Management, Cape Town, South Africa. JRC, IES, Ispra, Italy. UMCES, Horn Point Lab, Cambridge, MD USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Claustre, H (reprint author), Lab Oceanog Villefranche, BP 08, F-06238 Villefranche Sur Mer, France. EM claustre@obs-vlfr.fr RI Hooker, Stanford/E-2162-2012; CLAUSTRE, Herve/E-6877-2011 OI CLAUSTRE, Herve/0000-0001-6243-0258 NR 35 TC 62 Z9 63 U1 0 U2 12 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0304-4203 J9 MAR CHEM JI Mar. Chem. PD FEB PY 2004 VL 85 IS 1-2 BP 41 EP 61 DI 10.1016/j.marchem.2003.09.002 PG 21 WC Chemistry, Multidisciplinary; Oceanography SC Chemistry; Oceanography GA 764QH UT WOS:000188217200003 ER PT J AU Anderson, JLB Schultz, PH Heineck, JT AF Anderson, JLB Schultz, PH Heineck, JT TI Experimental ejection angles for oblique impacts: Implications for the subsurface flow-field SO METEORITICS & PLANETARY SCIENCE LA English DT Article ID HYPERVELOCITY IMPACT; CRATER; EXPLOSIVES; DIMENSIONS; PROJECTILE; CHICXULUB; SAND; PEAK AB A simple analytical solution for subsurface particle motions during impact cratering is useful for tracking the evolution of the transient crater shape at late times. A specific example of such an analytical solution is Maxwell's Z-Model, which is based on a point-source assumption. Here, the parameters for this model are constrained using measured ejection angles from both vertical and oblique experimental impacts at the NASA Ames Vertical Gun Range. Data from experiments reveal that impacts at angles as high as 45degrees to the target's surface generate subsurface flow-fields that are significantly different from those created by vertical impacts. The initial momentum of the projectile induces a subsurface momentum-driven flow-field that evolves in three dimensions of space and in time to an excavation flow-field during both vertical and oblique impacts. A single, stationary point-source model (specifically Maxwell's Z-Model), however, is found inadequate to explain this detailed evolution of the subsurface flow-field during oblique impacts. Because 45degrees is the most likely impact angle on planetary surfaces, a new analytical model based on a migrating point-source could prove quite useful. Such a model must address the effects of the subsurface flow-field evolution on crater excavation, ejecta deposition, and transient crater morphometry. C1 Brown Univ, Providence, RI 02912 USA. NASA, Ames Res Ctr, Expt Phys Grp, Moffett Field, CA 94035 USA. RP Anderson, JLB (reprint author), Brown Univ, Providence, RI 02912 USA. EM Jennifer_Anderson@brown.edu NR 54 TC 44 Z9 44 U1 0 U2 2 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 FEB PY 2004 VL 39 IS 2 BP 303 EP 320 PG 18 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 804XB UT WOS:000220330300009 ER PT J AU Gultepe, I Isaac, GA Key, J Intrieri, J Starr, DO Strawbridge, KB AF Gultepe, I Isaac, GA Key, J Intrieri, J Starr, DO Strawbridge, KB TI Dynamical and microphysical characteristics of Arctic clouds using integrated observations collected over SHEBA during the April 1998 FIRE.ACE flights of the Canadian Convair SO METEOROLOGY AND ATMOSPHERIC PHYSICS LA English DT Article ID EFFECTIVE PARTICLE-SIZE; RADAR OBSERVATIONS; CIRRUS CLOUDS; DOPPLER RADAR; RADIATIVE PROPERTIES; EFFECTIVE-RADIUS; AIRBORNE LIDAR; BOUNDARY-LAYER; ICE CLOUDS; LEADS AB The purpose of this study is to better understand the dynamical and microphysical processes within Arctic clouds, which occurred in April 1998 over the Surface Heat Budget of the Arctic Ocean (SHEBA) ship during the First ISCCP (International Satellite Cloud Climatology Project) Regional Experiment Arctic Cloud Experiment (FIRE.ACE). The observations from the four cases in the present study were collected by instruments mounted onboard the National Research Council (NRC) Convair, as well as, the National Oceanic and Atmospheric Administration (NOAA) Advanced Very High Resolution Radiometer (AVHRR) satellite, the SHEBA surface based NOAA Doppler radar (35 GHz, Ka-Band), and the NOAA depolarization lidar (0.523 mum) measurements. The aircraft observations were collected at 32 Hz (3-m scale). The Meteorological Services of Canada (MSC) lidar (1.064 mum) was operated onboard the Convair-580. The AVHRR observations, representing a 5-km horizontal resolution, were used to estimate particle size, phase, and optical thickness. Constant altitude flight legs were made at about 100 m over the ocean surface. Vertical air velocity (w), reflectivity and Doppler velocity, and backscatter and depolarization ratio values were used to define the size of the important dynamical structures. Ice crystal number concentration (N-i), ice water content (IWC), droplet number concentration (N-d), liquid water content (LWC) and characteristic particle size and shape were summarized for each case. The effective radius (r(eff)) values for liquid clouds obtained from in-situ and AVHRR observations were found comparable. The large variability in IWC can be due to undetected ice crystals at small size ranges. Mixed phased conditions in the AVHRR retrievals complicated the comparisons with in-situ data. N-i was found to be directly related to the history of the air-parcel dynamics e.g., w. The variability and differences in the parameters obtained from various platforms can be attributed to their instrumental capabilities, resolution, as well as the cloud development. C1 Meteorol Serv Canada, Cloud Phys Res Div, Toronto, ON M3H 5T4, Canada. Natl Environm Satellite Data & Informat Serv, NOAA, Madison, WI 53706 USA. NOAA, Environm Technol Lab, Boulder, CO 80303 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Meteorol Serv Canada, Air Qual Proc Res Div, Egbert, ON L0L 1NO, Canada. RP Gultepe, I (reprint author), Meteorol Serv Canada, Cloud Phys Res Div, 4905 Dufferin St, Toronto, ON M3H 5T4, Canada. EM ismail.gultepe@ec.gc.ca RI Key, Jeffrey/F-5597-2010; Intrieri, Janet/D-5608-2015 OI Key, Jeffrey/0000-0001-6109-3050; NR 72 TC 5 Z9 5 U1 0 U2 0 PU SPRINGER-VERLAG WIEN PI VIENNA PA SACHSENPLATZ 4-6, PO BOX 89, A-1201 VIENNA, AUSTRIA SN 0177-7971 J9 METEOROL ATMOS PHYS JI Meteorol. Atmos. Phys. PD FEB PY 2004 VL 85 IS 4 BP 235 EP 263 DI 10.1007/s00703-003-0009-z PG 29 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 800UX UT WOS:000220054300004 ER PT J AU Castro, VA Thrasher, AN Healy, M Ott, CM Pierson, DL AF Castro, VA Thrasher, AN Healy, M Ott, CM Pierson, DL TI Microbial characterization during the early habitation of the International Space Station SO MICROBIAL ECOLOGY LA English DT Article; Proceedings Paper CT International Workshop on Microbial Ecology and the Space Environment CY NOV 18-19, 2002 CL Tokyo, JAPAN SP Int Space Life Sci Working Grp ID DNA-SEQUENCE ANALYSIS; IDENTIFICATION AB An evaluation of the microbiota from air, water, and surface samples provided a baseline of microbial characterization onboard the International Space Station (ISS) to gain insight into bacterial and fungal contamination during the initial stages of construction and habitation. Using 16S genetic sequencing and rep-PCR, 63 bacterial strains were isolated for identification and fingerprinted for microbial tracking. Of the bacterial strains that were isolated and fingerprinted, 19 displayed similarity to each other. The use of these molecular tools allowed for the identification of bacteria not previously identified using automated biochemical analysis and provided a clear indication of the source of several ISS contaminants. Strains of Brad),rhizobium and Sphingomonas unable to be identified using sequencing were identified by comparison of rep-PCR DNA fingerprints. Distinct DNA fingerprints for several strains of Methylobacterium provided a clear indication of the source of an ISS water supply contaminant. Fungal and bacterial data acquired during monitoring do not suggest there is a current microbial hazard to the spacecraft, nor does any trend indicate a potential health risk. Previous spacecraft environmental analysis indicated that microbial contamination will increase with time and will require continued surveillance. C1 NASA, Lyndon B Johnson Space Ctr, EASI Wyle Labs, Microbiol Lab, Houston, TX 77058 USA. Bacterial Barcodes Inc, Houston, TX 77054 USA. NASA, Lyndon B Johnson Space Ctr, Habitabil & Environm Factors Off, Houston, TX 77058 USA. RP Castro, VA (reprint author), NASA, Lyndon B Johnson Space Ctr, EASI Wyle Labs, Microbiol Lab, Houston, TX 77058 USA. EM victoria.a.castrol@jsc.nasa.gov NR 23 TC 73 Z9 79 U1 1 U2 15 PU SPRINGER-VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0095-3628 J9 MICROBIAL ECOL JI Microb. Ecol. PD FEB PY 2004 VL 47 IS 2 BP 119 EP 126 DI 10.1007/s00248-003-1030-y PG 8 WC Ecology; Marine & Freshwater Biology; Microbiology SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Microbiology GA 818CL UT WOS:000221223100003 PM 14749908 ER PT J AU Ott, CM Bruce, RJ Pierson, DL AF Ott, CM Bruce, RJ Pierson, DL TI Microbial characterization of free floating condensate aboard the Mir space station SO MICROBIAL ECOLOGY LA English DT Article; Proceedings Paper CT International Workshop on Microbial Ecology and the Space Environment CY NOV 18-19, 2002 CL Tokyo, JAPAN SP Int Space Life Sci Working Grp ID SPACEFLIGHT AB Three samples of humidity condensate that had accumulated behind panels aboard the Russian space station Mir were collected and returned to earth for analysis. As these floating masses of liquid come into contact with the astronauts and the engineering systems, they have the potential to affect both crew health and systems performance. Using a combination of culturing techniques, a wide variety of organisms were isolated included Escherichia coli, Serratia marcescens, and a presumed Legionella species. In addition, microscopic analysis indicated the presence of protozoa, dust mites, and spirochetes. These findings suggest the need for more comprehensive microbial analysis of the environment through the use of new methodologies to allow a more thorough risk assessment of spacecraft. C1 NASA, Lyndon B Johnson Space Ctr, EASI Wyle Labs, Microbiol Lab, Houston, TX 77058 USA. NASA, Lyndon B Johnson Space Ctr, Habitabil & Environm Factors Off, Houston, TX 77058 USA. RP Ott, CM (reprint author), NASA, Lyndon B Johnson Space Ctr, EASI Wyle Labs, Microbiol Lab, 1290 Hercules Dr, Houston, TX 77058 USA. EM charlie.m.ott1@jsc.nasa.gov NR 5 TC 26 Z9 29 U1 0 U2 6 PU SPRINGER-VERLAG PI NEW YORK PA 175 FIFTH AVE, NEW YORK, NY 10010 USA SN 0095-3628 J9 MICROBIAL ECOL JI Microb. Ecol. PD FEB PY 2004 VL 47 IS 2 BP 133 EP 136 DI 10.1007/s00248-003-1038-3 PG 4 WC Ecology; Marine & Freshwater Biology; Microbiology SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Microbiology GA 818CL UT WOS:000221223100005 PM 14569419 ER PT J AU La Duc, MT Kern, R Venkateswaran, K AF La Duc, MT Kern, R Venkateswaran, K TI Microbial monitoring of spacecraft and associated environments SO MICROBIAL ECOLOGY LA English DT Article; Proceedings Paper CT International Workshop on Microbial Ecology and the Space Environment CY NOV 18-19, 2002 CL Tokyo, JAPAN SP Int Space Life Sci Working Grp ID MICROBIOLOGICAL PROFILES; MICROORGANISMS; DIVERSITY; STATION; BOARD; ATP AB Rapid microbial monitoring technologies are invaluable in assessing contamination of spacecraft and associated environments. Universal and widespread elements of microbial structure and chemistry are logical targets for assessing microbial burden. Several biomarkers such as ATP, LPS, and DNA (ribosomal or spore-specific), were targeted to quantify either total bioburden or specific types of microbial contamination. The findings of these assays were compared with conventional, culture-dependent methods. This review evaluates the applicability and efficacy of some of these methods in monitoring the microbial burden of spacecraft and associated environments. Samples were collected from the surfaces of spacecraft, from surfaces of assembly facilities, and from drinking water reservoirs aboard the International Space Station (ISS). Culture-dependent techniques found species of Bacillus to be dominant on these surfaces. In contrast, rapid, culture-independent techniques revealed the presence of many Gram-positive and Gram-negative microorganisms, as well as actinomycetes and fungi. These included both cultivable and noncultivable microbes, findings further confirmed by DNA-based microbial detection techniques. Although the ISS drinking water was devoid of cultivable microbes, molecular-based techniques retrieved DNA sequences of numerous opportunistic pathogens. Each of the methods tested in this study has its advantages, and by coupling two or more of these techniques even more reliable information as to microbial burden is rapidly obtained. C1 CALTECH, Jet Prop Lab, Biotechnol & Planetary Protect Grp, Pasadena, CA 91109 USA. RP Venkateswaran, K (reprint author), CALTECH, Jet Prop Lab, Biotechnol & Planetary Protect Grp, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM kjvenkat@jpl.nasa.gov NR 32 TC 83 Z9 87 U1 2 U2 21 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0095-3628 J9 MICROB ECOL JI Microb. Ecol. PD FEB PY 2004 VL 47 IS 2 BP 150 EP 158 DI 10.1007/s00248-003-1012-0 PG 9 WC Ecology; Marine & Freshwater Biology; Microbiology SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Microbiology GA 818CL UT WOS:000221223100007 PM 14749906 ER PT J AU Link, L Sawyer, J Venkateswaran, K Nicholson, W AF Link, L Sawyer, J Venkateswaran, K Nicholson, W TI Extreme spore UV resistance of Bacillus pumilus isolates obtained from an ultraclean spacecraft assembly facility SO MICROBIAL ECOLOGY LA English DT Article; Proceedings Paper CT International Workshop on Microbial Ecology and the Space Environment CY NOV 18-19, 2002 CL Tokyo, JAPAN SP Int Space Life Sci Working Grp ID TERRESTRIAL; ENDOSPORES; MARS AB Recent environmental microbial sampling of the ultra-clean Spacecraft Assembly Facility at NASA Jet Propulsion Laboratory (JPL-SAF) identified spores of Bacillus pumilus as major culturable bacterial contaminants found on and around spacecraft. As part of an effort to assess the efficacy of various spacecraft sterilants, purified spores of 10 JPL-SAF B. pumilus isolates were subjected to 254-nm UV and their UV resistance was compared to spores of standard B. subtilis biodosimetry strains. Spores of six of the 10 JPL-SAF isolates were significantly more resistant to UV than the B. subtilis biodosimetry strain, and one of the JPL-SAF isolates, B. pumilus SAFR-032, exhibited the highest degree of spore UV resistance observed by any Bacillus spp. encountered to date. C1 Univ Arizona, Dept Vet Sci & Microbiol, Tucson, AZ 85721 USA. CALTECH, NASA Jet Prop Lab, Biotechnol & Planetary Protect Grp, Pasadena, CA 91109 USA. RP Nicholson, W (reprint author), Univ Arizona, Dept Vet Sci & Microbiol, Tucson, AZ 85721 USA. EM WLN@u.arizona.edu NR 16 TC 66 Z9 66 U1 0 U2 7 PU SPRINGER PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 0095-3628 J9 MICROB ECOL JI Microb. Ecol. PD FEB PY 2004 VL 47 IS 2 BP 159 EP 163 DI 10.1007/s00248-003-1029-4 PG 5 WC Ecology; Marine & Freshwater Biology; Microbiology SC Environmental Sciences & Ecology; Marine & Freshwater Biology; Microbiology GA 818CL UT WOS:000221223100008 PM 14502417 ER PT J AU Cooper, SM Cruden, BA Meyyappan, M Raju, R Roy, S AF Cooper, SM Cruden, BA Meyyappan, M Raju, R Roy, S TI Gas transport characteristics through a carbon nanotubule SO NANO LETTERS LA English DT Article ID ALUMINUM-OXIDE; TEMPLATE SYNTHESIS; MEMBRANES; ARRAYS; FLOW AB We report the first determination of the slip coefficient for tubular carbon structures that have been produced by chemical vapor deposition on a porous alumina substrate with nominal pore diameters of 200 nm. A uniform 20-30 nm thick carbonaceous coating was formed over the pores. The permeability of the porous alumina was then measured using a pressure/flow apparatus. A finite element code with adjustable slip boundary conditions was used to model transport through the alumina. In the absence of a carbonaceous material, transport was well described by diffuse reflection at the wall. When a carbon nanotubule was present, however, a tangential-momentum accommodation coefficient, or,, of 0.52 +/- 0.1 was predicted for argon, nitrogen, and oxygen. C1 NASA, Ames Res Ctr, Ctr Nanotechnol, Moffett Field, CA 94035 USA. Kettering Univ, Dept Mech Engn, Computat Plasma Dynam Lab, Flint, MI 48504 USA. RP Cruden, BA (reprint author), NASA, Ames Res Ctr, Ctr Nanotechnol, Moffett Field, CA 94035 USA. EM bcruden@mail.arc.nasa.gov RI Roy, Subrata/A-7493-2009 NR 23 TC 41 Z9 41 U1 2 U2 13 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 1530-6984 J9 NANO LETT JI Nano Lett. PD FEB PY 2004 VL 4 IS 2 BP 377 EP 381 DI 10.1021/nl0350682 PG 5 WC Chemistry, Multidisciplinary; Chemistry, Physical; Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Physics, Applied; Physics, Condensed Matter SC Chemistry; Science & Technology - Other Topics; Materials Science; Physics GA 774EA UT WOS:000188965700038 ER PT J AU Weidenspointner, G Harris, MJ Ferguson, C Sturner, S Teegarden, BJ AF Weidenspointner, G Harris, MJ Ferguson, C Sturner, S Teegarden, BJ TI MGGPOD: a Monte Carlo suite for modelling instrumental backgrounds in gamma-ray astronomy and its application to Wind/TGRS and INTEGRAL/SPI SO NEW ASTRONOMY REVIEWS LA English DT Article; Proceedings Paper CT International Workshop on Astronomy with Radioactivities IV and Filling and Sensitivity Gap in MeV Astronomy CY MAY 26-30, 2003 CL Kloster Seeon, GERMANY DE computer modeling and simulation; astronomy; gamma-ray telescopes ID SPECTROMETER AB We have developed MGGPOD, a suite of Monte Carlo codes built around the widely used GEANT (Version 3.21) package, to simulate ab initio the physical processes relevant for the production of instrumental backgrounds. These include the build-up and delayed decay of radioactive isotopes as well as the prompt de-excitation of excited nuclei, both of which give rise to a plethora of instrumental gamma-ray background lines in addition to continuum background. We demonstrate the capabilities of the MGGPOD suite by modelling high resolution gamma-ray spectra recorded by the Transient Gamma-Ray Spectrometer (TGRS) on board Wind and the SPI spectrometer on board the recently launched INTEGRAL observatory. (C) 2003 Elsevier B.V. All rights reserved. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. USRA, Lanham, MD 20706 USA. CESR, F-31028 Toulouse, France. Univ Southampton, Southampton SO17 1BJ, Hants, England. RP Weidenspointner, G (reprint author), NASA, Goddard Space Flight Ctr, Code 661, Greenbelt, MD 20771 USA. EM georg.weidenspointner@cesr.fr NR 8 TC 14 Z9 15 U1 0 U2 1 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 1387-6473 J9 NEW ASTRON REV JI New Astron. Rev. PD FEB PY 2004 VL 48 IS 1-4 BP 227 EP 230 DI 10.1016/j.newar.2003.11.031 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 777MF UT WOS:000189181600041 ER PT J AU Hartmann, DH Grindlay, J Band, D Blandford, R Craig, W Fishman, GJ Gehrels, N Harrison, F Hong, J Kouveliotou, C Loeb, A Woosley, SE AF Hartmann, DH Grindlay, J Band, D Blandford, R Craig, W Fishman, GJ Gehrels, N Harrison, F Hong, J Kouveliotou, C Loeb, A Woosley, SE TI Tracing cosmic star formation with EXIST SO NEW ASTRONOMY REVIEWS LA English DT Article; Proceedings Paper CT 4th International Workshop on Astronomy with Radioactivities - Filling and Sensitivity Gap in MeV Astronomy CY MAY 26-30, 2003 CL Kloster Seeon, GERMANY DE gamma-ray telescopes; supernovae; novae; bursts; black holes; stars-formation ID GAMMA-RAY BURSTS; CLASSICAL NOVAE; SN 1987A; SUPERNOVA; NUCLEOSYNTHESIS; EMISSION; UNIVERSE; GALAXY; PROBE; AL-26 AB We describe the energetic X-ray imaging survey telescope EXIST, designed to carry out a sensitive all-sky survey in the 10-600 keV band. The primary goal of EXIST is to find black holes in the local and distant universe. EXIST also traces cosmic star formation via gamma-ray bursts and gamma-ray lines from radioactivity ejected by supernovae and novae. (C) 2003 Elsevier B.V. All rights reserved. C1 Clemson Univ, Clemson, SC 29634 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA. Lawrence Livermore Natl Lab, Livermore, CA USA. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. Harvard Univ, CfA, Cambridge, MA 02138 USA. CALTECH, Pasadena, CA 91125 USA. Univ Calif Santa Cruz, Lick Observ, Santa Cruz, CA 95064 USA. RP Hartmann, DH (reprint author), Clemson Univ, Clemson, SC 29634 USA. EM hdieter@clemson.edu RI Gehrels, Neil/D-2971-2012 NR 55 TC 3 Z9 3 U1 0 U2 0 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 1387-6473 J9 NEW ASTRON REV JI New Astron. Rev. PD FEB PY 2004 VL 48 IS 1-4 BP 237 EP 241 DI 10.1016/j.newar.2003.11.055 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 777MF UT WOS:000189181600043 ER PT J AU Kanbach, G Andritschke, R Schopper, F Schonfelder, V Zoglauer, A Bloser, PF Hunter, SD Ryan, JA McConnell, M Reglero, V DiCocco, G Knodlseder, J AF Kanbach, G Andritschke, R Schopper, F Schonfelder, V Zoglauer, A Bloser, PF Hunter, SD Ryan, JA McConnell, M Reglero, V DiCocco, G Knodlseder, J TI The MEGA project SO NEW ASTRONOMY REVIEWS LA English DT Article; Proceedings Paper CT 4th International Workshop on Astronomy with Radioactivities - Filling and Sensitivity Gap in MeV Astronomy CY MAY 26-30, 2003 CL Kloster Seeon, GERMANY DE gamma-ray astronomy; medium energies; MEGA AB We describe the development of a new telescope for Medium Energy Gamma-Ray Astronomy (MEGA) for the energy band 0.4-50 MeV. As a successor to COMPTEL and EGRET (low energies), MEGA aims to improve the sensitivity for astronomical sources by at least an order of magnitude. It could thus fill the severe sensitivity gap between scheduled or operating hard-X-ray and high-energy gamma-ray missions and open the way for a future Advanced Compton Telescope. MEGA records and images gamma-rays by completely tracking Compton and Pair creation events in a stack of double sided Si-strip track detectors surrounded by a pixelated CsI calorimeter. A scaled down prototype has been built and calibrations using radioactive sources and exposures to an accelerator generated gamma-ray beam were performed in 2003. A balloon flight is planned for 2004. (C) 2003 Published by Elsevier B.V. C1 Max Planck Inst Extraterr Phys, D-37075 Garching, Germany. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ New Hampshire, Durham, NH 03824 USA. Univ Valencia, GACE, E-46003 Valencia, Spain. CNR, IASF, Bologna, Italy. CESR, Toulouse, France. RP Kanbach, G (reprint author), Max Planck Inst Extraterr Phys, D-37075 Garching, Germany. EM gok@mpe.mpg.de RI Hunter, Stanley/D-2942-2012 NR 3 TC 39 Z9 39 U1 0 U2 4 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 1387-6473 J9 NEW ASTRON REV JI New Astron. Rev. PD FEB PY 2004 VL 48 IS 1-4 BP 275 EP 280 DI 10.1016/j.newar.2003.11.056 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 777MF UT WOS:000189181600049 ER PT J AU Andritschke, R Zoglauer, A Kanbach, G Schrey, F Bloser, PF Hunter, S Macri, J Miller, R Litvinenko, V Ahmed, M Donchev, A AF Andritschke, R Zoglauer, A Kanbach, G Schrey, F Bloser, PF Hunter, S Macri, J Miller, R Litvinenko, V Ahmed, M Donchev, A TI The calibration setup of the MEGA prototype at the high intensity gamma-ray source SO NEW ASTRONOMY REVIEWS LA English DT Article; Proceedings Paper CT 4th International Workshop on Astronomy with Radioactivities - Filling and Sensitivity Gap in MeV Astronomy CY MAY 26-30, 2003 CL Kloster Seeon, GERMANY DE gamma-ray astronomy; Compton telescope; pair telescope; MEGA; calibration; HI gamma S AB We describe the calibration measurements of the MEGA prototype, a tracking Compton and pair creation telescope. The measurements were performed at the high intensity gamma-ray source (HIgammaS) facility from April 21 to May 06, 2003. The main goal of this calibration was directed at higher energies, above those available from radioactive lab sources, and at polarization. A total of 15.5 x 10(6) triggered events at 10 energies in the range of 0.7-49 MeV and at six angles of incidence (0degrees-180degrees) were recorded. (C) 2003 Elsevier B.V. All rights reserved. C1 Max Planck Inst Extraterr Phys, D-37075 Garching, Germany. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ New Hampshire, Dept Phys, Durham, NH 03824 USA. Duke Univ, Dept Phys, Free Electron Laser Lab, Durham, NC 27706 USA. RP Andritschke, R (reprint author), Max Planck Inst Extraterr Phys, D-37075 Garching, Germany. EM randrits@mpe.mpg.de RI Hunter, Stanley/D-2942-2012 NR 3 TC 10 Z9 10 U1 0 U2 2 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 1387-6473 J9 NEW ASTRON REV JI New Astron. Rev. PD FEB PY 2004 VL 48 IS 1-4 BP 281 EP 285 DI 10.1016/j.newar.2003.11.054 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 777MF UT WOS:000189181600050 ER PT J AU Bloser, PF Hunter, SD Ryan, JM McConnell, ML Miller, RS Jackson, TN Bai, B Jung, S AF Bloser, PF Hunter, SD Ryan, JM McConnell, ML Miller, RS Jackson, TN Bai, B Jung, S TI Applications of gas imaging micro-well detectors to an advanced Compton telescope SO NEW ASTRONOMY REVIEWS LA English DT Article; Proceedings Paper CT International Workshop on Astronomy with Radioactivities IV and Filling and Sensitivity Gap in MeV Astronomy CY MAY 26-30, 2003 CL Kloster Seeon, GERMANY DE gamma rays : observations; instrumentation : detectors; space vehicles : instruments; techniques : high angular resolution ID GAMMA-RAY ASTRONOMY AB We present a concept for an advanced Compton telescope (ACT) based on the use of pixelized gas micro-well detectors to form a three-dimensional electron track imager. A micro-well detector consists of an array of individual micro-patterned proportional counters opposite a planar drift electrode. When combined with thin film transistor array readouts, large gas volumes may be imaged with very good spatial and energy resolution at reasonable cost. The third dimension is determined from the drift time of the ionization electrons. The primary advantage of this approach is the excellent tracking of the Compton recoil electron that is possible in a gas volume. Such good electron tracking allows us to reduce the point spread function of a single incident photon dramatically, greatly improving the imaging capability and sensitivity. The polarization sensitivity, which relies on events with large Compton scattering angles, is particularly enhanced. We describe a possible ACT implementation of this technique, in which the gas tracking volume is surrounded by a CA calorimeter, and present our plans to build and test a small prototype over the next three years. (C) 2003 Elsevier B.V. All rights reserved. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ New Hampshire, Ctr Space Sci, Durham, NH 03824 USA. Penn State Univ, Ctr Thin Film Devices, University Pk, PA 16802 USA. RP Bloser, PF (reprint author), NASA, Goddard Space Flight Ctr, Code 661, Greenbelt, MD 20771 USA. EM bloser@milkyway.gsfc.nasa.gov RI Jackson, Thomas/A-4224-2012; Hunter, Stanley/D-2942-2012 NR 8 TC 5 Z9 5 U1 0 U2 1 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 1387-6473 J9 NEW ASTRON REV JI New Astron. Rev. PD FEB PY 2004 VL 48 IS 1-4 BP 299 EP 303 DI 10.1016/j.newar.2003.11.034 PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 777MF UT WOS:000189181600053 ER PT J AU Haino, S Abe, K Anraku, K Fuke, H Hams, T Ikeda, N Itasaki, A Izumi, K Kumazawa, T Lee, MH Maeno, T Makida, Y Matsuda, S Matsui, N Matsumoto, H Matsumoto, K Mitchell, JW Moiseev, AA Nishimura, J Nozaki, M Omiya, H Orito, S Ormes, JF Sanuki, T Sasaki, M Seo, ES Shikaze, Y Streitmatter, RE Suzuki, J Takasugi, Y Takeuchi, S Tanaka, K Taniguchi, T Tanizaki, K Yamagami, T Yamamoto, A Yamamoto, Y Yamato, K Yoshida, T Yoshimura, K AF Haino, S Abe, K Anraku, K Fuke, H Hams, T Ikeda, N Itasaki, A Izumi, K Kumazawa, T Lee, MH Maeno, T Makida, Y Matsuda, S Matsui, N Matsumoto, H Matsumoto, K Mitchell, JW Moiseev, AA Nishimura, J Nozaki, M Omiya, H Orito, S Ormes, JF Sanuki, T Sasaki, M Seo, ES Shikaze, Y Streitmatter, RE Suzuki, J Takasugi, Y Takeuchi, S Tanaka, K Taniguchi, T Tanizaki, K Yamagami, T Yamamoto, A Yamamoto, Y Yamato, K Yoshida, T Yoshimura, K TI Progress of the BESS Superconducting Spectrometer SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article; Proceedings Paper CT 9th Pisa Meeting on Advanced Detectors CY MAY 25-31, 2003 CL LA BIODOLA, ITALY DE balloon-borne payload; magnetic-rigidity spectrometer; cosmic ray ID RAY ANTIPROTON SPECTRUM; SOLAR MINIMUM; ONBOARD BESS; FLUX; HELIUM; SPACE AB Balloon-borne Experiment with a Superconducting Spectrometer (BESS) is a balloon-borne spectrometer to study elementary particle phenomena in the early Universe as well as the origin and the propagation of cosmic radiation. The instrument has a unique feature of a thin superconducting solenoid which enables a large acceptance with a cylindrical configuration. Nine balloon flights have been successfully carried out since 1993. In 2002, the detector was upgraded as the BESS-TeV spectrometer to extend primary cosmic-ray spectra up to 1 TeV. For further studies of low-energy antiprotons, a new spectrometer, BESS-Polar, with a ultra-thin superconducting solenoid is being developed for long duration balloon flights in Antarctica. (C) 2003 Elsevier B.V. All rights reserved. C1 Univ Tokyo, Tokyo 1130033, Japan. Kobe Univ, Kobe, Hyogo 6578501, Japan. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. KEK, High Energy Accelerator Res Org, Tsukuba, Ibaraki 3050801, Japan. Univ Maryland, College Pk, MD 20742 USA. ISAS, Kanagawa 2298510, Japan. RP Haino, S (reprint author), Univ Tokyo, Tokyo 1130033, Japan. EM haino@icepps.s.u-tokyo.ac.jp OI Seo, Eun-Suk/0000-0001-8682-805X NR 22 TC 12 Z9 12 U1 0 U2 1 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD FEB 1 PY 2004 VL 518 IS 1-2 BP 167 EP 171 DI 10.1016/j.nima.2003.10.051 PG 5 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 774CA UT WOS:000188961100046 ER PT J AU Kaewpijit, S Le Moigne, J El-Ghazawi, T AF Kaewpijit, S Le Moigne, J El-Ghazawi, T TI Feature reduction of hyperspectral imagery using hybrid wavelet-principal component analysis SO OPTICAL ENGINEERING LA English DT Article DE dimension reduction; principal component analysis; wavelet decomposition; maximum likelihood ID CLASSIFICATION; INFORMATION AB Hyperspectral imagery can provide very valuable information on land cover classes. However, it also presents many challenges in data analysis and interpretation as a result of the large amounts of data collected. For example, conventional methods for land use and land cover classifications may not be directly applicable. Such conventional methods typically require a preprocessing step to transform high dimensional data to a lower dimension, mostly by eliminating data redundancy. For decades, principal component analysis (PCA) has been widely used to decorrelate spectral bands for reducing dimensionality. It is a useful technique if the spectral class structure of the transformed data is distributed along the first few axes. Otherwise, the transformed data may be similar to the original data. In such cases, we have shown in an earlier work that the wavelet decomposition technique is a better approach. Wavelet decomposition can reduce hyperspectral data in the spectral domain for each pixel. By carefully combining IPCA and wavelet techniques, we engender a new method that benefits from the strength of both techniques. The intent of the hybrid method is to provide a tradeoff between the accuracy and speed, as compared with PCA and wavelet methods. The effectiveness of this method is demonstrated by using hyperspectral data from the Airborne Visible Infrared Imaging Spectrometer (AVIRIS) hyperspectral instrument. The experimental results show that, for high reduction rates, the hybrid method is superior to pure PCA and to pure wavelet-based techniques. (C) 2004 Society of Photo-Optical Instrumentation Engineers. C1 George Washington Univ, Dept Elect & Comp Engn, Washington, DC 20052 USA. NASA, Goddard Space Flight Ctr, Appl Informat Sci Branch, Greenbelt, MD 20771 USA. George Washington Univ, Dept Elect & Comp Sci, Washington, DC 20052 USA. RP Kaewpijit, S (reprint author), George Washington Univ, Dept Elect & Comp Engn, Washington, DC 20052 USA. EM tarek@seas.gwu.edu NR 21 TC 11 Z9 12 U1 1 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 FEB PY 2004 VL 43 IS 2 BP 350 EP 362 DI 10.1117/1.1637907 PG 13 WC Optics SC Optics GA 803MZ UT WOS:000220236500012 ER PT J AU Liebe, CC Scherr, L Willson, R AF Liebe, CC Scherr, L Willson, R TI Sun-induced veiling glare in dusty camera optics SO OPTICAL ENGINEERING LA English DT Article DE Mars; Jet Propulsion Laboratory; Mars exploration rovers; camera; sun; veiling glare; dust; optics AB The National Aeronautical and Space Administration (NASA) is planning to send two Mars Exploration Rovers (MER) to Mars in 2003. Onboard these rovers will be a number of scientific and engineering cameras. Mars is a dusty place, so dust will accumulate on the front surface of the camera optics. When the sun shines on the dusty front surface, light will be scattered to the detector. This increases glare and reduces contrast. The rover lenses must work, even when the sun shines on the front element. Therefore, the veiling glare has been evaluated by experiments. We discuss these experiments and the results. (C) 2004 Society of Photo-Optical Instrumentation Engineers. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Liebe, CC (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 6 TC 2 Z9 2 U1 0 U2 0 PU SPIE-INT SOCIETY OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98225 USA SN 0091-3286 J9 OPT ENG JI Opt. Eng. PD FEB PY 2004 VL 43 IS 2 BP 493 EP 499 DI 10.1117/1.1635835 PG 7 WC Optics SC Optics GA 803MZ UT WOS:000220236500032 ER PT J AU Brasier, M Green, O Lindsay, J Steele, A AF Brasier, M Green, O Lindsay, J Steele, A TI Earth's oldest (similar to 3.5 Ga) fossils and the 'Early Eden hypothesis': Questioning the evidence SO ORIGINS OF LIFE AND EVOLUTION OF THE BIOSPHERE LA English DT Article DE Archaean; carbon isotopes; early Earth; fossils; hydrothermal; photosynthesis ID RAMAN SPECTROSCOPY COMMUNICATION; WESTERN-AUSTRALIA; EARLIEST FOSSILS; NORTH-POLE; WARRAWOONA GROUP; LIFE; CHERT; MICROFOSSILS; STROMATOLITES; GREENLAND AB We question the biogenicity of putative bacterial and cyanobacterial 'microfossils' from 3465 Ma Apex cherts of the Warrawoona Group in Western Australia. They are challenged on the basis of integrated multidisciplinary evidence obtained from field and fabric mapping plus new high-resolution research into their context, sedimentology, filament morphology, 'septation' and arrangement. They cannot be distinguished from ( and are reinterpreted as) secondary artefacts of amorphous carbon that formed during devitrification of successive generations of carbonaceous hydrothermal dyke vein quartz. Similar structures occur within associated carbonaceous volcanic glass. The null hypothesis of an abiotic or prebiotic origin for such ancient carbonaceous matter is sustained until mutually supporting contextural, morphological and geochemical evidence for a bacterial rather than abiotic origin is forthcoming. C1 Univ Oxford, Dept Earth Sci, Oxford OX1 3PR, England. NASA, JST SA13, JSC Astrobiol Inst, Houston, TX 77058 USA. Carnegie Inst Washington, Geophys Lab, Washington, DC 20015 USA. RP Brasier, M (reprint author), Univ Oxford, Dept Earth Sci, Parks Rd, Oxford OX1 3PR, England. NR 52 TC 65 Z9 68 U1 1 U2 15 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0169-6149 J9 ORIGINS LIFE EVOL B JI Orig. Life Evol. Biosph. PD FEB PY 2004 VL 34 IS 1-2 BP 257 EP 269 DI 10.1023/B:ORIG.0000009845.62244.d3 PG 13 WC Biology SC Life Sciences & Biomedicine - Other Topics GA 756ZX UT WOS:000187516600023 PM 14979661 ER PT J AU Kumar, A Qiu, ZY Acrivos, A Khusid, B Jacqmin, D AF Kumar, A Qiu, ZY Acrivos, A Khusid, B Jacqmin, D TI Combined negative dielectrophoresis and phase separation in nondilute suspensions subject to a high-gradient ac electric field SO PHYSICAL REVIEW E LA English DT Article ID POSITIVE DIELECTROPHORESIS; COLLOIDAL SUSPENSIONS; INDUCED AGGREGATION; DNA; MICROFLUIDICS; PARTICLES AB Experiments were conducted on concentrated suspensions of neutrally buoyant particles which exhibit negative dielectrophoresis. We found that, due to interparticle electrical interactions, such suspensions undergo a phase separation when subjected to a high-gradient ac field (similar tokV/mm) and form a propagating distinct front between the regions enriched with and depleted of particles. A generalization of our theory for the thermodynamics of the field-induced phase transitions in suspensions of polarized particles [Phys. Rev. E 52, 1669 (1995); 54, 5428 (1996); 60, 3015 (1999)] is proposed for the front propagation, and its predictions are shown to be consistent with the experiments even though the model contains no fitting parameters. The combination of field-induced dielectrophoresis and phase transition provides a method for strongly concentrating particles in prespecified regions of dielectrophoretic devices. C1 CUNY City Coll, Levich Inst, New York, NY 10031 USA. New Jersey Inst Technol, Newark, NJ 07102 USA. NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Kumar, A (reprint author), CUNY City Coll, Levich Inst, 140th St & Convent Ave, New York, NY 10031 USA. EM anil@levdec.engr.ccny.cuny.edu; qiu@lisgi6.engr.ccny.cuny.edu; acrivos@scisun.sci.ccny.cuny.edu; khusid@adm.njit.edu; fsdavid@tess.lerc.nasa.gov NR 24 TC 28 Z9 28 U1 0 U2 8 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 FEB PY 2004 VL 69 IS 2 AR 021402 DI 10.1103/PhysRevE.69.021402 PN 1 PG 10 WC Physics, Fluids & Plasmas; Physics, Mathematical SC Physics GA 803UG UT WOS:000220255400020 PM 14995439 ER PT J AU Chen, X Rame, E Garoff, S AF Chen, X Rame, E Garoff, S TI The effects of thin and ultrathin liquid films on dynamic wetting SO PHYSICS OF FLUIDS LA English DT Article ID MOVING CONTACT LINES; SOLID-SURFACE; HYDRODYNAMICS; INTERFACE; FLUID; SHAPES; FORCES; ANGLES AB We examine the effects of thick (micron scale) fluid films and thin molecular scale (10-100 Angstrom) films on the hydrodynamics near advancing contact lines by measuring the liquid-vapor interface shape of a meniscus and comparing the measurements to three models. Using flow visualization, we directly observe the fluid flow field near the moving contact line and give a qualitative description of the stagnation point and dividing streamline emanating from the contact line region. For thick films, when the capillary number satisfies Ca(a/d)(3/2)less than or equal toO(1) (where d is the film thickness and a is the macroscopic length scale of the system), the liquid-vapor interface is bent only slightly by the viscous flow and the effective dynamic contact angle is close to zero. As Ca approaches O(1/ln(a/d)), a modulated wedge-like region appears at some distance from the film and expands both away from and toward the film as Ca increases. The dynamic contact angle approaches the classic power law behavior as this region expands. For molecularly thin films, the liquid-vapor interface shape within microns of the moving contact line is correctly described by theoretical models based purely on hydrodynamics and without disjoining pressure effects. (C) 2004 American Institute of Physics. C1 Carnegie Mellon Univ, Dept Phys, Pittsburgh, PA 15213 USA. Carnegie Mellon Univ, Ctr Complex Fluids Engn, Pittsburgh, PA 15213 USA. NASA, Glenn Res Ctr, Natl Ctr Micrograv Res, Cleveland, OH 44135 USA. RP Chen, X (reprint author), Carnegie Mellon Univ, Dept Phys, Pittsburgh, PA 15213 USA. RI Garoff, Stephen/P-7629-2014 OI Garoff, Stephen/0000-0001-8148-8535 NR 34 TC 12 Z9 12 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 1070-6631 J9 PHYS FLUIDS JI Phys. Fluids PD FEB PY 2004 VL 16 IS 2 BP 287 EP 297 DI 10.1063/1.1632498 PG 11 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA 762GM UT WOS:000187963600007 ER PT J AU Smith, JG Connell, JW Delozier, DM Lillehei, PT Watson, KA Lin, Y Zhou, B Sun, YP AF Smith, JG Connell, JW Delozier, DM Lillehei, PT Watson, KA Lin, Y Zhou, B Sun, YP TI Space durable polymer/carbon nanotube films for electrostatic charge mitigation SO POLYMER LA English DT Article DE carbon nanotubes; colorless polyimides; nanocomposites ID WALLED CARBON NANOTUBES; ELECTRICAL-PROPERTIES; FUNCTIONALIZATION; DISPERSION; COMPOSITES; HYBRIDS AB Low color, flexible, space environmentally durable polymeric materials possessing sufficient surface resistivity (10(6)-10(10) Omega/square) for electrostatic charge (ESC) mitigation are of interest for potential applications on Gossamer spacecraft as thin film membranes on antennas, large lightweight space optics, and second surface mirrors. One method of incorporating intrinsic ESC mitigation while maintaining low color, flexibility, and optical clarity is through the utilization of single-walled carbon nanotubes (SWNTs). However, SWNTs are difficult to uniformly disperse in the polymer matrix. The approach reported herein employed amide acid polymers endcapped with alkoxysilane groups that could condense with oxygen containing functionalities that were present on the ends of SWNTs as a result of the oxidative purification treatment. These SWNTs were combined with the endcapped amide acid polymers in solution and subsequently cast as unoriented thin films. Two examples possessed electrical conductivity (measured as surface resistance and surface resistivity) sufficient for ESC mitigation at loading levels of less than or equal to 0.08 wt% SWNT as well as good retention of thermo-optical properties. The percolation threshold was determined to lie between 0.03 and 0.04 wt% SWNT loading. Electrical conductivity of the film remained unaffected even after harsh mechanical manipulation. Published by Elsevier Ltd. C1 NASA, Langley Res Ctr, Adv Mat & Proc Branch, Hampton, VA 23681 USA. Natl Inst Aerosp, Hampton, VA 23666 USA. Clemson Univ, Dept Chem, Howard L Hunter Chem Lab, Clemson, SC 29634 USA. RP Connell, JW (reprint author), NASA, Langley Res Ctr, Adv Mat & Proc Branch, Mail Stop 226, Hampton, VA 23681 USA. EM j.w.connell@larc.nasa.gov RI Lillehei, Peter/C-9196-2009 OI Lillehei, Peter/0000-0001-8183-9980 NR 35 TC 137 Z9 139 U1 5 U2 23 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0032-3861 J9 POLYMER JI Polymer PD FEB 1 PY 2004 VL 45 IS 3 BP 825 EP 836 DI 10.1016/j.polymer.2003.11.024 PG 12 WC Polymer Science SC Polymer Science GA 765TY UT WOS:000188300900011 ER PT J AU Lucia, DJ Beran, PS Silva, WA AF Lucia, DJ Beran, PS Silva, WA TI Reduced-order modeling: new approaches for computational physics SO PROGRESS IN AEROSPACE SCIENCES LA English DT Review DE reduced-order modeling; proper orthogonal decomposition; Galerkin projection; Volterra series; harmonic balance ID PROPER-ORTHOGONAL DECOMPOSITION; UNSTEADY AERODYNAMIC ANALYSIS; NAVIER-STOKES EQUATIONS; DOMAIN DECOMPOSITION; AEROELASTIC RESPONSE; BURGERS-EQUATION; AIRFOIL FLUTTER; MOVING SHOCKS; VISCOUS FLOWS; SYSTEMS AB In this paper, we review the development of new reduced-order modeling techniques and discuss their applicability to various problems in computational physics. Emphasis is given to methods based on Volterra series representations, the proper orthogonal decomposition, and harmonic balance. Results are reported for different nonlinear systems to provide clear examples of the construction and use of reduced-order models (ROMs), particularly in the multi-disciplinary field of computational aeroelasticity. Unsteady aerodynamic and aeroelastic behaviors of two-dimensional and three-dimensional geometries are described. Large increases in computational efficiency are obtained through the use of ROMs, thereby justifying the initial computational expense of constructing these models and motivating their use for multi-disciplinary design analysis. (C) 2003 Elsevier Ltd. All rights reserved. C1 USAF, Res Lab, Wright Patterson AFB, OH 45433 USA. AFRL, VASD, Wright Patterson AFB, OH 45433 USA. NASA, Langley Res Ctr, Aeroelast Branch, Hampton, VA 23681 USA. RP Lucia, DJ (reprint author), USAF, Res Lab, 2130 8th St,Suite 1,Bldg 45, Wright Patterson AFB, OH 45433 USA. EM david.lucia@wpafb.af.mil; philip.beran@wpafb.af.mil NR 171 TC 190 Z9 214 U1 8 U2 51 PU PERGAMON-ELSEVIER SCIENCE LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND SN 0376-0421 J9 PROG AEROSP SCI JI Prog. Aeosp. Sci. PD FEB PY 2004 VL 40 IS 1-2 BP 51 EP 117 DI 10.1016/j.paerosci.2003.12.001 PG 67 WC Engineering, Aerospace SC Engineering GA 803YZ UT WOS:000220267700002 ER PT J AU Shukla, S Seal, S Ludwig, L Parish, C AF Shukla, S Seal, S Ludwig, L Parish, C TI Nanocrystalline indium oxide-doped tin oxide thin film as low temperature hydrogen sensor SO SENSORS AND ACTUATORS B-CHEMICAL LA English DT Article DE nanocrystalline indium oxide-doped tin oxide; Pt-sputtered thin film; low temperature hydrogen sensor ID GAS-SENSING PROPERTIES; ION-ASSISTED DEPOSITION; SOL-GEL PROCESS; PARTICLE-SIZE; H-2 SENSOR; SNO2; PALLADIUM; CO; NANOPARTICLES; SENSITIVITY AB Hydrogen gas, within the concentration range of 100 ppm-4 vol.%, is successfully sensed at lower operating temperatures, 25 and 50degreesC, using the Pt-sputtered sol-gel dip-coated nanocrystalline (6-7 nm) 6.5 mol% In2O3-doped SnO2 semiconductor thin (100-150 nm) film sensor. Typically, for 1000 ppm of hydrogen, the maximum sensitivity values of 32 and 1600% are observed at 25 and 50degreesC, respectively; while for 2 vol.% hydrogen, the maximum sensitivity values of 50 and 70,000% are recorded at 25 and 50degreesC, respectively. At 25degreesC, for 4 vol.% (explosive limit as set by NASA) hydrogen, the maximum hydrogen gas sensitivity values of 107,887 and 2083% are observed for the Pt-sputtered thin films calcined at 500 and 600degreesC, respectively. (C) 2003 Elsevier B.V. All rights reserved. C1 Univ Cent Florida, Dept Mech Mat Aerosp Engn, Orlando, FL 32816 USA. Univ Cent Florida, AMPAC, Orlando, FL 32816 USA. NASA, Kennedy Space Ctr, Titusville, FL USA. RP Seal, S (reprint author), Univ Cent Florida, Dept Mech Mat Aerosp Engn, Engn 381,4000 Cent Florida Blvd, Orlando, FL 32816 USA. EM sseal@pegasus.ec.ucf.edu OI Shukla, Satyajit/0000-0002-7947-8095 NR 52 TC 163 Z9 166 U1 7 U2 57 PU ELSEVIER SCIENCE SA PI LAUSANNE PA PO BOX 564, 1001 LAUSANNE, SWITZERLAND SN 0925-4005 J9 SENSOR ACTUAT B-CHEM JI Sens. Actuator B-Chem. PD FEB 1 PY 2004 VL 97 IS 2-3 BP 256 EP 265 DI 10.1016/j.snb.2003.08.025 PG 10 WC Chemistry, Analytical; Electrochemistry; Instruments & Instrumentation SC Chemistry; Electrochemistry; Instruments & Instrumentation GA 770AL UT WOS:000188700800013 ER PT J AU Choi, SH Song, KD Golembiewskii, W Chu, SH King, GC AF Choi, SH Song, KD Golembiewskii, W Chu, SH King, GC TI Microwave power for smart material actuators SO SMART MATERIALS & STRUCTURES LA English DT Article ID ANTENNA; SURFACE AB The concept of microwave-driven smart material actuators was envisioned and developed as the best option to alleviate the complexity and weight associated with a hard-wire-networked power and control system for smart actuator arrays. The patch recterma array was initially designed for high current output, but has undergone further development for high voltage output devices used in shape control applications. Test results show that more than 200 V of output were obtained from a 6 x 6 array at a far-field exposure (1.8 m away) with an X-band input power of 18 W. The 6 x 6 array patch recterma was designed to theoretically generate voltages up to 540 V, but practically it has generated voltages in the range between 200 and 300 V. Testing was also performed with a thin layer composite unimorph ferroelectric driver and sensor and electro-active paper as smart actuators attached to the 6 x 6 array. Flexible dipole recterma arrays built on thin-film-based flexible membranes are most applicable for NASA's various missions, such as microwave-driven shape controls for aircraft morphing and large, ultra-lightweight space structures. An array of dipole rectennas was designed for high voltage output by densely populating Schottky barrier diodes to drive piezoelectric or electrostrictive actuators. The dipole rectenna array will eventually be integrated with a power allocation and distribution logic circuit and microbatteries for storage of excessive power. The roadmap for the development of wireless power drivers based on the recterma array for shape control requires the development of new membrane materials with proper dielectric constants that are suitable for dipole recterma arrays. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. Norfolk State Univ, Norfolk, VA 23504 USA. RP Choi, SH (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 24 TC 34 Z9 34 U1 0 U2 8 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0964-1726 J9 SMART MATER STRUCT JI Smart Mater. Struct. PD FEB PY 2004 VL 13 IS 1 BP 38 EP 48 AR PII S0964-1726(04)70975-1 DI 10.1088/0964-1726/13/1/005 PG 11 WC Instruments & Instrumentation; Materials Science, Multidisciplinary SC Instruments & Instrumentation; Materials Science GA 778RY UT WOS:000189255600005 ER PT J AU Keenan, FP Katsiyannis, AC Ramsbottom, CA Bell, KL Brosius, JW Davila, JM Thomas, RJ AF Keenan, FP Katsiyannis, AC Ramsbottom, CA Bell, KL Brosius, JW Davila, JM Thomas, RJ TI A comparison of theoretical Si VIII emission line ratios with observations from SERTS SO SOLAR PHYSICS LA English DT Article ID EUV-ROCKET-TELESCOPE; SOLAR ACTIVE-REGION; EXTREME-ULTRAVIOLET SPECTRUM; I ISOELECTRONIC SEQUENCE; SPECTROGRAPH SERTS; ATOMIC DATABASE; OPACITY CALCULATIONS; COLLISION STRENGTHS; TRANSITIONS; CHIANTI AB Recent R-matrix calculations of electron impact excitation rates in N-like Si VIII are used to derive theoretical emission line intensity ratios involving 2s(2)2p(3)-2s2p(4) transitions in the 216 -320 Angstrom wavelength range. A comparison of these with an extensive dataset of solar active region, quiet-Sun, sub-flare and off-limb observations, obtained during rocket flights of the Solar EUV Research Telescope and Spectrograph (SERTS), indicates that the ratio R-1 = I(216.94 Angstrom)/I(319.84 Angstrom) may provide a usable electron density diagnostic for coronal plasmas. The ratio involves two lines of comparable intensity, and varies by a factor of about 5 over the useful density range of 10(8)-10(11) cm(-3). However R-2 = I(276.85 Angstrom)/I(319.84 Angstrom) and R-3 = I(277.05 Angstrom)/I(319.84 Angstrom) show very poor agreement between theory and observation, due to the severe blending of the 276.85 and 277.05 Angstrom lines with Si VII and Mg VII transitions, respectively, making the ratios unsuitable as density diagnostics. The 314.35 Angstrom feature of Si VIII also appears to be blended, with the other species contributing around 20% to the total line flux. C1 Queens Univ Belfast, Dept Pure & Appl Phys, Belfast BT7 1NN, Antrim, North Ireland. Queens Univ Belfast, Dept Appl Math & Theoret Phys, Belfast BT7 1NN, Antrim, North Ireland. NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. Catholic Univ Amer, Dept Phys, Washington, DC 20064 USA. RP Keenan, FP (reprint author), Queens Univ Belfast, Dept Pure & Appl Phys, Belfast BT7 1NN, Antrim, North Ireland. RI Katsiyannis, Thanassis/L-8496-2013 NR 28 TC 1 Z9 1 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 FEB PY 2004 VL 219 IS 2 BP 251 EP 263 DI 10.1023/B:SOLA.0000023001.61242.e1 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 809ZK UT WOS:000220674400004 ER PT J AU Feynman, J Ruzmaikin, A AF Feynman, J Ruzmaikin, A TI A high-speed erupting-prominence CME: A bridge between types SO SOLAR PHYSICS LA English DT Article ID CORONAL MASS EJECTIONS; FILAMENT; FLARES AB Several studies have indicated that there may be two distinct types of coronal mass ejections (CMEs); a high-velocity bright energetic type associated with flares, and a smaller slower less impressive type associated with erupting prominences. How valid is this distinction? We analyze a CME combining attributes of both types, a high-velocity bright CME associated with an erupting prominence. A study of this event and several others allows us to argue that the apparent differences separating the two types may be an observational effect. Our results are consistent with a single CME process for both flare-associated and filament-associated CMEs. This process consists of three stages. The initial stage is brought about by the emergence of new magnetic flux, which interacts with the pre-existing magnetic configuration and results in a slow rise of the magnetic structure, which later becomes the CME. The second stage is a fast reconnection phase with flaring and a sudden increase of the rise velocity of the magnetic structure. It also includes a rapidly increasing CME acceleration followed by a rapidly falling acceleration. The third stage or CME propagation stage shows only slow changes in the acceleration and finally the velocity becomes constant. LASCO observes only the third stage. The differences found between observed flare-associated and prominence-associated CME velocity behavior appear to be primarily due to the relative heights in the corona at which the erupting structures form. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Feynman, J (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 24 TC 26 Z9 28 U1 0 U2 3 PU KLUWER ACADEMIC PUBL PI DORDRECHT PA VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS SN 0038-0938 J9 SOL PHYS JI Sol. Phys. PD FEB PY 2004 VL 219 IS 2 BP 301 EP 313 DI 10.1023/B:SOLA.0000022996.53206.9d PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 809ZK UT WOS:000220674400008 ER PT J AU Rummel, JD Billings, L AF Rummel, JD Billings, L TI Issues in planetary protection: policy, protocol and implementation SO SPACE POLICY LA English DT Article DE astrobiology; planetary protection; sample return; solar system exploration; space science ID MARS; TERRESTRIAL; EJECTION; LIFE AB Planetary protection is NASA's term for the practice of protecting solar system bodies from Earth life while protecting Earth from life that may be brought back from other solar system bodies. Spacefaring nations will soon begin retrieving samples from Mars and other solar system bodies. For these samples, planetary protection is in order, and measures are already in place to prevent the forward contamination of Mars and other bodies by Earth microbes and the backward contamination of Earth by possible extraterrestrial life. A major goal of planetary protection controls on forward contamination is to preserve the planetary record of natural processes by preventing human-caused microbial introductions. (C) 2003 Elsevier Ltd. All rights reserved. C1 SETI Inst, Arlington, VA 22207 USA. NASA, Off Space Sci, Washington, DC 20546 USA. RP Billings, L (reprint author), SETI Inst, 3654 Vacat Lane, Arlington, VA 22207 USA. EM lbillings@seti.org NR 24 TC 20 Z9 20 U1 0 U2 2 PU ELSEVIER SCI LTD PI OXFORD PA THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND SN 0265-9646 J9 SPACE POLICY JI Space Policy PD FEB PY 2004 VL 20 IS 1 BP 49 EP 54 DI 10.1016/j.spacepol.2003.11.005 PG 6 WC International Relations; Social Sciences, Interdisciplinary SC International Relations; Social Sciences - Other Topics GA 778GT UT WOS:000189231700008 ER PT J AU Peters, W Krol, MC Fortuin, JPF Kelder, HM Thompson, AM Becker, CR Lelieveld, J Crutzen, PJ AF Peters, W Krol, MC Fortuin, JPF Kelder, HM Thompson, AM Becker, CR Lelieveld, J Crutzen, PJ TI Tropospheric ozone over a tropical Atlantic station in the Northern hemisphere: Paramaribo, Surinam SO TELLUS SERIES B-CHEMICAL AND PHYSICAL METEOROLOGY LA English DT Article ID UPPER-AIR-CIRCULATION; MODIFIED-RESIDUAL METHOD; SOUTH-ATLANTIC; SATELLITE MEASUREMENTS; MAPPING SPECTROMETER; COLUMN OZONE; TRACE-A; TOMS; TRANSPORT; MAXIMUM AB We present an analysis of 2.5 yr of weekly ozone soundings conducted at a new monitoring station in Paramaribo, Surinam (6degreesN, 55degreesW). This is currently one of only three ozone sounding stations in the Northern Hemisphere (NH) tropics, and the only one in the equatorial Atlantic region. Paramaribo is part of the Southern Hemisphere Additional Ozone Sounding program (SHADOZ). Owing to its position close to the equator, the inter-tropical convergence zone (ITCZ) passes over Paramaribo twice per year, which results in a semi-annual seasonality of many parameters including relative humidity and ozone. The dataset from Paramaribo is used to: (1) evaluate the ozone variability relative to precipitation, atmospheric circulation patterns and biomass burning; (2) contrast ozone at the NH equatorial Atlantic with that at nearby Southern Hemisphere (SH) stations Natal (6degreesS, 35degreesW) and Ascension (8degreesS, 14degreesW); (3) compare the seasonality of tropospheric ozone with a satellite-derived ozone product: tropical tropospheric ozone columns from the modified residual method (MR-TTOC). We find that Paramaribo is a distinctly Atlantic station. Despite its position north of the equator, it resembles nearby SH stations during most of the year. Transport patterns in the lower and middle troposphere during February and March differ from SH stations, which leads to a seasonality of ozone with two maxima. MR-TTOC over Paramaribo does not match the observed seasonality of ozone due to the use of a SH ozone sonde climatology in the MR method. The Paramaribo ozone record is used to suggest an improvement for Northern Hemisphere MR-TTOC retrievals. We conclude that station Paramaribo shows unique features in the region, and clearly adds new information to the existing SHADOZ record. C1 NOAA, Climate Monitoring & Diagnost Lab, Boulder, CO 80305 USA. Inst Marine & Atmospher Res Utrecht, NL-3508 TA Utrecht, Netherlands. Koninklijke Nederlandse Meteorol Dienst, NL-3730 AE De Bilt, Netherlands. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Meteorol Dienst Suriname, Paramaribo, Surinam. Max Planck Inst Chem, D-55128 Mainz, Germany. RP Peters, W (reprint author), NOAA, Climate Monitoring & Diagnost Lab, 325 Broadway, Boulder, CO 80305 USA. EM Wouter.Peters@noaa.gov RI Peters, Wouter/B-8305-2008; Krol, Maarten/B-3597-2010; Crutzen, Paul/F-6044-2012; Krol, Maarten/E-3414-2013; Lelieveld, Johannes/A-1986-2013; Thompson, Anne /C-3649-2014 OI Peters, Wouter/0000-0001-8166-2070; Thompson, Anne /0000-0002-7829-0920 NR 49 TC 13 Z9 13 U1 2 U2 3 PU CO-ACTION PUBLISHING PI JARFALLA PA RIPVAGEN 7, JARFALLA, SE-175 64, SWEDEN SN 0280-6509 EI 1600-0889 J9 TELLUS B JI Tellus Ser. B-Chem. Phys. Meteorol. PD FEB PY 2004 VL 56 IS 1 BP 21 EP 34 DI 10.1111/j.1600-0889.2004.00083.x PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 775XE UT WOS:000189085300002 ER PT J AU Street, KW Marchetti, M Vander Wal, RL Tomasek, AJ AF Street, KW Marchetti, M Vander Wal, RL Tomasek, AJ TI Evaluation of the tribological behavior of nano-onions in Krytox 143AB SO TRIBOLOGY LETTERS LA English DT Article DE perfluoropolyalkylether; carbon nano-onions; spiral orbit tribometry ID SPIRAL ORBIT TRIBOMETRY; RAMAN; TEMPERATURE; GRAPHITE AB Nanoparticles have been widely developed over the past ten years and have found several applications. This work presents the use of carbon nano-onions, i.e., nanoparticles, as a potential additive in an oil for aerospace application. The lifetimes were tested in ambient air and ultrahigh vacuum. Tribochemical products were characterized by micro Raman and FT-IR spectroscopies. It was shown that these particles can provide adequate lubrication very similar to graphitic material only when run in air. C1 NASA, Glenn Res Ctr, Natl Ctr Micrograv Res, Cleveland, OH 44135 USA. RP Street, KW (reprint author), NASA, Glenn Res Ctr, Natl Ctr Micrograv Res, 21000 Brookpk Rd,MS 23-2, Cleveland, OH 44135 USA. NR 22 TC 25 Z9 27 U1 1 U2 4 PU KLUWER ACADEMIC/PLENUM PUBL PI NEW YORK PA 233 SPRING ST, NEW YORK, NY 10013 USA SN 1023-8883 J9 TRIBOL LETT JI Tribol. Lett. PD FEB PY 2004 VL 16 IS 1-2 BP 143 EP 149 DI 10.1023/B:TRIL.0000009724.01711.f4 PG 7 WC Engineering, Chemical; Engineering, Mechanical SC Engineering GA 756ZU UT WOS:000187516300017 ER PT J AU DellaCorte, C AF DellaCorte, C TI Give them a little and, thankfully, they want more ... SO TRIBOLOGY & LUBRICATION TECHNOLOGY 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. EM cdellacorte@stle.org 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 TRIBOL LUBR TECHNOL JI Tribol. Lubr. Technol. PD FEB PY 2004 VL 60 IS 2 BP 6 EP 6 PG 1 WC Engineering, Mechanical SC Engineering GA 770YD UT WOS:000188758200002 ER PT J AU Lary, DJ Muller, MD Mussa, HY AF Lary, DJ Muller, MD Mussa, HY TI Using neural networks to describe tracer correlations SO ATMOSPHERIC CHEMISTRY AND PHYSICS LA English DT Article ID LOWER STRATOSPHERE; UNIVERSAL APPROXIMATORS; UPPER TROPOSPHERE; FUZZY-SYSTEMS; GAS BUDGETS; N2O; NITROGEN; OZONE; NO(Y); O-3 AB Neural networks are ideally suited to describe the spatial and temporal dependence of tracer-tracer correlations. The neural network performs well even in regions where the correlations are less compact and normally a family of correlation curves would be required. For example, the CH(4)-N2(O) correlation can be well described using a neural network trained with the latitude, pressure, time of year, and CH(4) volume mixing ratio (v.m.r.). In this study a neural network using Quickprop learning and one hidden layer with eight nodes was able to reproduce the CH(4)-N(2)O correlation with a correlation coefficient between simulated and training values of 0.9995. Such an accurate representation of tracer-tracer correlations allows more use to be made of long-term datasets to constrain chemical models. Such as the dataset from the Halogen Occultation Experiment (HALOE) which has continuously observed CH(4) (but not N(2)O) from 1991 till the present. The neural network Fortran code used is available for download. C1 NASA, Global Modelling & Assimilat Off, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Maryland Baltimore Cty, GEST, Baltimore, MD 21228 USA. Univ Cambridge, Dept Chem, Unilever Cambridge Ctr, Cambridge CB2 1TN, England. CNR, Washington, DC 20418 USA. RP Lary, DJ (reprint author), NASA, Global Modelling & Assimilat Off, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. EM David.Lary@umbc.edu RI Lary, David/A-6163-2010 NR 23 TC 10 Z9 12 U1 0 U2 0 PU COPERNICUS GESELLSCHAFT MBH PI GOTTINGEN PA BAHNHOFSALLEE 1E, GOTTINGEN, 37081, GERMANY SN 1680-7316 J9 ATMOS CHEM PHYS JI Atmos. Chem. Phys. PD JAN 31 PY 2004 VL 4 BP 143 EP 146 PG 4 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 771FY UT WOS:000188776000001 ER PT J AU Hsu, J Prather, MJ Wild, O Sundet, JK Isaksen, ISA Browell, EV Avery, MA Sachse, GW AF Hsu, J Prather, MJ Wild, O Sundet, JK Isaksen, ISA Browell, EV Avery, MA Sachse, GW TI Are the TRACE-P measurements representative of the western Pacific during March 2001? SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE TRACE-P measurements; CTM stimulations; representativeness; sampling bias; ozone and CO2 comparisons; EOF; PDFs ID ASIAN CONTINENTAL OUTFLOW; NORTHERN-HEMISPHERE; TROPOSPHERIC OZONE; ARCTIC OSCILLATION; CHEMICAL EVOLUTION; CARBON-MONOXIDE; CLIMATE-CHANGE; TRANSPORT; VARIABILITY; REGIMES AB [1] Observations of CO and O-3 from the Transport and Chemical Evolution over the Pacific (TRACE-P) campaign are compared with modeled distributions from the FRSGC/ UCI CTM driven by the Oslo T63L40 ECMWF forecast meteorology. The model-measurement comparison is made within the context of how well the TRACE-P observations represent the springtime chemistry and ozone distributions over eastern Asia and the western Pacific in March 2001 and uses the four-dimensional (4-D) extended domain from the model to provide unbiased statistics. A key question is whether the limited sampling density or mission strategy led to a statistically biased sample. To address this question, we examine a diverse range of statistical analyses of the observations of CO and O-3. The middle percentiles of the cumulative probability functions for CO in the free troposphere are representative ( and reproduced by the CTM), but those in the boundary layer are not. The frequency of low-CO, stratospheric influence is well matched along flight tracks but is atypical of the extended domain. The percentiles of the latitude-by-height distribution of lidar O-3 show how the CTM reproduces the nonrepresentative clumpy nature of the observations but has too low a tropopause about the jet region (30-35N). Adaptive kernel estimation of the 2-D probability density of O-3-CO correlations shows a very good simulation of two different chemical regimes ( stratospheric and polluted) that is quite different from the extended domain but also highlights the failure to predict CO > 400 ppb. Empirical orthogonal function analysis of the O-3 vertical profiles shows how six EOFs can effectively describe the 4-D structures of O-3 over this entire domain. The latitude-by-longitude maps of the principal components provide an excellent test of the CTM simulation along flight tracks and clearly show the unique sampling of O-3 events by the TRACE-P flights. In many cases the ability of the model to simulate the nonrepresentative observations implies a clear skill in matching the unique meteorological and chemical features of the region. C1 Univ Calif Irvine, Dept Earth Syst Sci, Irvine, CA 92697 USA. Frontier Res Syst Global Change, Kanagawa 2360001, Japan. Univ Oslo, Dept Geophys, N-0315 Oslo, Norway. NASA, Atmospher Sci Competency, Langley Res Ctr, Hampton, VA 23681 USA. RP Hsu, J (reprint author), Univ Calif Irvine, Dept Earth Syst Sci, 2101 Croul Hall, Irvine, CA 92697 USA. EM juno@halo.ps.uci.edu; mprather@uci.edu; oliver@jamstec.go.jp; j.k.sundet@geofysikk.uio.no; ivar.isaksen@geo.uio.no; edward.v.browell@nasa.gov; m.a.avery@larc.nasa.gov; glen.w.sachse@nasa.gov RI Wild, Oliver/A-4909-2009; Hsu, Juno/A-7221-2011 OI Wild, Oliver/0000-0002-6227-7035; NR 33 TC 12 Z9 12 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 JAN 31 PY 2004 VL 109 IS D2 AR D02314 DI 10.1029/2003JD004002 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 772XF UT WOS:000188867500003 ER PT J AU Konopka, P Steinhorst, HM Grooss, JU Gunther, G Muller, R Elkins, JW Jost, HJ Richard, E Schmidt, U Toon, G McKenna, DS AF Konopka, P Steinhorst, HM Grooss, JU Gunther, G Muller, R Elkins, JW Jost, HJ Richard, E Schmidt, U Toon, G McKenna, DS TI Mixing and ozone loss in the 1999-2000 Arctic vortex: Simulations with the three-dimensional Chemical Lagrangian Model of the Stratosphere (CLaMS) SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE stratosphere; Lagrangian transport; mixing; ozone loss; SOLVE/THESEO 2000; CLaMS ID BALLOON-BORNE OBSERVATIONS; NORTHERN POLAR VORTEX; AIRCRAFT MEASUREMENTS; POTENTIAL VORTICITY; WINTER 1999/2000; DEPLETION; FORMULATION; ADVECTION; CHEMISTRY; DESCENT AB [1] The three-dimensional (3-D) formulation of the Chemical Lagrangian Model of the Stratosphere (CLaMS-3d) is presented that extends the isentropic version of CLaMS to cross-isentropic transport. The cross-isentropic velocities of the Lagrangian air parcels are calculated with a radiation module and by taking into account profiles of ozone and water vapor derived from a HALOE climatology. The 3-D extension of mixing maintains the most important feature of the 2-D version as mixing is mainly controlled by the horizontal deformations of the wind fields. In the 3-D version, mixing is additionally driven by the vertical shear in the flow. The impact of the intensity of mixing in the 3-D model formulation on simulated tracer distributions is elucidated by comparing observations of CH4, Halon-1211, and ozone from satellite, balloon, and ER-2 aircraft during the SOLVE/ THESEO-2000 campaign. CLaMS-3d simulations span the time period from early December 1999 to the middle of March 2000, with air parcels extending over the Northern Hemisphere in the vertical range between 350 and 1400 K. The adjustment of the CLaMS-3d mixing parameters to optimize agreement with observations was obtained for strongly inhomogeneous, deformation-induced mixing that affects only about 10% of the air parcels per day. The optimal choice of the aspect ratio a defining the ratio of the mean horizontal and vertical separation between the air parcels was determined to be 250 for model configuration with a horizontal resolution r(0) = 100 km. By transporting ozone in CLaMS-3d as a passive tracer, the chemical ozone loss was inferred as the difference between the observed and simulated ozone profiles. The results show, in agreement with previous studies, a substantial ozone loss between 380 and 520 K with a maximum loss at 460 K of about 1.9 ppmv, i.e., of over 60% locally, from December to the middle of March 2000. During this period, the impact of isentropic mixing across the vortex edge outweighs the effect of the spatially inhomogeneous ( differential) descent on the tracer/ ozone correlations in the vortex. Mixing into the vortex shifts the early winter reference tracer/ ozone correlation to higher values, which may lead to an underestimate of chemical ozone loss, on average by 0.4 and 0.1 ppmv in the entire vortex and the vortex core, respectively. C1 Forschungszentrum Julich, Inst Stratospher Chem ICGI, D-52425 Julich, Germany. NOAA, Aeron Lab, Boulder, CO 80303 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Goethe Univ Frankfurt, Inst Meteorol & Geophys, D-60325 Frankfurt, Germany. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Natl Ctr Atmospher Res, Boulder, CO 80307 USA. RP Konopka, P (reprint author), Forschungszentrum Julich, Inst Stratospher Chem ICGI, Postfach 1913, D-52425 Julich, Germany. EM p.konopka@fz-juelich.de; h.steinhorst@fz-jeulich.de; j.-u.grooss@fz-juelich.de; g.guenther@fz-juelich.de; ro.mueller@fz.juelich.de; jelkins@cmdl.noaa.gov; hjost@mail.arc.nasa.gov; erik.c.richard@noaa.gov; uschmidt@meteor.uni-frankfurt.de; toon@mark4sun.jpl.nasa.gov; danny@acd.ucar.edu RI Guenther, Gebhard/K-7583-2012; Muller, Rolf/A-6669-2013; Konopka, Paul/A-7329-2013; GrooSS, Jens-Uwe/A-7315-2013; McKenna, Daniel/E-7806-2014 OI Guenther, Gebhard/0000-0003-4111-6221; Muller, Rolf/0000-0002-5024-9977; GrooSS, Jens-Uwe/0000-0002-9485-866X; McKenna, Daniel/0000-0002-4360-4782 NR 39 TC 58 Z9 58 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 JAN 31 PY 2004 VL 109 IS D2 AR D02315 DI 10.1029/2003JD003792 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 772XF UT WOS:000188867500001 ER PT J AU Preisler, EJ Strittmatter, RP McGill, TC Hill, CJ AF Preisler, EJ Strittmatter, RP McGill, TC Hill, CJ TI Nitridation of epitaxially grown 6.1 angstrom semiconductors studied by X-ray photoelectron spectroscopy SO APPLIED SURFACE SCIENCE LA English DT Article DE semiconductors; X-ray photoelectron spectroscopy; epitaxial surfaces ID MOLECULAR-BEAM EPITAXY; MEAN FREE-PATH; GALLIUM ANTIMONIDE; ELECTRICAL-PROPERTIES; SURFACE PASSIVATION; SULFUR PASSIVATION; ATOMIC NITROGEN; DIODES; IMPROVEMENT; GAAS AB We present a detailed analysis of the state of surfaces of the 6.1 Angstrom family of semiconductors (InAs, GaSb and AlSb) under exposure to a nitrogen plasma. X-ray photoelectron spectroscopy (XPS) is used to determine the species created at the surface and their relative abundance. We find evidence that clean epitaxial surfaces exposed to the plasma form both V-N (SbN and AsN) and III-N (AlN, GaN and InN) compounds, but in different amounts and different proportions for each of the materials. (C) 2003 Published by Elsevier B.V. C1 CALTECH, TJ Watson Sr Lab Appl Phys, Pasadena, CA 91125 USA. Jet Prop Lab, Pasadena, CA USA. RP Strittmatter, RP (reprint author), CALTECH, TJ Watson Sr Lab Appl Phys, 1200 Calif Blvd, Pasadena, CA 91125 USA. EM strittmr@its.caltech.edu NR 30 TC 1 Z9 1 U1 2 U2 6 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0169-4332 J9 APPL SURF SCI JI Appl. Surf. Sci. PD JAN 30 PY 2004 VL 222 IS 1-4 BP 6 EP 12 DI 10.1016/j.apsusc.2003.08.017 PG 7 WC Chemistry, Physical; Materials Science, Coatings & Films; Physics, Applied; Physics, Condensed Matter SC Chemistry; Materials Science; Physics GA 761YP UT WOS:000187943300002 ER PT J AU Brooks, SD Toon, OB Tolbert, MA Baumgardner, D Gandrud, BW Browell, EV Flentje, H Wilson, JC AF Brooks, SD Toon, OB Tolbert, MA Baumgardner, D Gandrud, BW Browell, EV Flentje, H Wilson, JC TI Polar stratospheric clouds during SOLVE/THESEO: Comparison of lidar observations with in situ measurements SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE polar stratospheric cloud; MASP; lidar; SOLVE; mixed-phase clouds ID LARGE HNO3-CONTAINING PARTICLES; NITRIC-ACID TRIHYDRATE; ARCTIC STRATOSPHERE; SULFURIC-ACID; REFRACTIVE-INDEXES; LIQUID PARTICLES; VAPOR-PRESSURES; PHYSICAL STATE; AEROSOL; WINTER AB Polar stratospheric clouds (PSCs) were observed on several flights during the 1999/2000 SOLVE/THESEO mission. Here we present an analysis of PSC size distribution, composition, and particle phase based on near coincident measurements using the Multiangle Aerosol Spectrometer Probe (MASP) and Focused Cavity Aerosol Spectrometer (FCAS III) on board the ER-2 as well as lidar instruments on board the DC-8 and Falcon aircrafts. We calculate the aerosol backscatter ratios and aerosol depolarization ratios at infrared and visible wavelengths based on the particle size distributions measured by the MASP and FCAS III instruments. We then compare our calculations to observed lidar measurements taken from on board the DC-8 and Falcon aircraft, which flew the same flight paths as the ER-2 on 20 January and 3 February 2000, respectively. Our comparison shows that calculations based on the mixed clouds containing small (submicrometer) spherical particles and large (2.5-22 mm diameter) nonspherical particles seen by the FCAS III and MASP are consistent with lidar observations. Our analysis shows that the infrared aerosol depolarization ratio must be measured to detect and identify mixed PSC clouds and that relying only on measurements of depolarization in the visible causes incorrect identification of mixed clouds as solution droplets. This study suggests that mixed clouds of supercooled ternary solutions were observed in coexistence with larger solid nitric acid hydrate particles. C1 Univ Colorado, Dept Chem & Biochem, Boulder, CO 80309 USA. Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. Univ Colorado, Program Atmospher & Ocean Sci, Boulder, CO 80309 USA. Univ Colorado, Atmospher & Space Phys Lab, Boulder, CO 80309 USA. Univ Nacl Autonoma Mexico, Ctr Ciencias Atmosfera, Mexico City 04510, DF, Mexico. Natl Ctr Atmospher Res, Boulder, CO 80307 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. Deutsch Zentrum Luft & Raumfahrt, Inst Phys Atnosphare, D-82237 Wessling, Germany. Univ Denver, Dept Engn, Denver, CO 80208 USA. RP Colorado State Univ, Dept Atmospher Sci, Ft Collins, CO 80523 USA. EM sbrooks@lamar.colostate.edu; toon@lasp.colorado.edu; tolbert@spot.colorado.edu; darrel@servidor.unam.mx; gandrud@particlemetrics.com; e.v.browell@nasa.gov; harald.flentje@dlr.de; jwilson@du.edu RI Brooks, Sarah/H-1176-2012 NR 45 TC 10 Z9 10 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 JAN 30 PY 2004 VL 109 IS D2 AR D02212 DI 10.1029/2003JD003463 PG 14 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 772XE UT WOS:000188867400001 ER PT J AU Ilchenko, VS Savchenkov, AA Matsko, AB Maleki, L AF Ilchenko, VS Savchenkov, AA Matsko, AB Maleki, L TI Nonlinear optics and crystalline whispering gallery mode cavities SO PHYSICAL REVIEW LETTERS LA English DT Article ID FUSED-SILICA MICROSPHERES; RAYLEIGH-SCATTERING; MICROWAVE RECEIVER; RESONANCES; MICRODROPLETS; MICROCAVITY; MODULATOR AB We demonstrate parametric frequency doubling in a whispering gallery cavity made of periodically poled lithium niobate. This demonstration is an example of utility of such crystalline optical whispering gallery resonators with very high Q factors, which we have fabricated. 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 25 TC 201 Z9 202 U1 13 U2 63 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD JAN 30 PY 2004 VL 92 IS 4 AR 043903 DI 10.1103/PhysRevLett.92.043903 PG 4 WC Physics, Multidisciplinary SC Physics GA 770TU UT WOS:000188747600023 PM 14995375 ER PT J AU Gamon, JA Huemmrich, KF Peddle, DR Chen, J Fuentes, D Hall, FG Kimball, JS Goetz, S Gu, J McDonald, KC Miller, JR Moghaddam, M Rahman, AF Roujean, JL Smith, EA Walthall, CL Zarco-Tejada, P Hu, B Fernandes, R Cihlar, J AF Gamon, JA Huemmrich, KF Peddle, DR Chen, J Fuentes, D Hall, FG Kimball, JS Goetz, S Gu, J McDonald, KC Miller, JR Moghaddam, M Rahman, AF Roujean, JL Smith, EA Walthall, CL Zarco-Tejada, P Hu, B Fernandes, R Cihlar, J TI Remote sensing in BOREAS: Lessons leamed SO REMOTE SENSING OF ENVIRONMENT LA English DT Review DE Boreal forest; remote sensing; carbon cycle; land cover ID LEAF-AREA INDEX; SURFACE PARAMETERIZATION SCHEMES; PHOTOCHEMICAL REFLECTANCE INDEX; LIGHT INTERACTION-MODEL; NET PRIMARY PRODUCTION; 4-SCALE LINEAR-MODEL; LAND-COVER; BIDIRECTIONAL REFLECTANCE; USE EFFICIENCY; ECOSYSTEM-ATMOSPHERE AB The Boreal Ecosystem Atmosphere Study (BOREAS) was a large, multiyear internationally supported study designed to improve our understanding of the boreal forest biome and its interactions with the atmosphere, biosphere, and the carbon cycle in the face of global climate change. In the initial phase of this study (early 1990s), remote sensing played a key role by providing products needed for planning and modeling. During and after the main BOREAS field campaigns (1994 and 1996), innovative remote sensing approaches and analyses expanded our understanding of the boreal forest in four key areas: (1) definition of vegetation structure, (2) land-cover classification, (3) assessment of the carbon balance, and (4) links between surface properties, weather, and climate. In addition to six BOREAS special issues and over 500 journal papers, a principal legacy of BOREAS is its well-documented and publicly available database, which provides a lasting scientific resource and opportunity to further advance our understanding of this critical northern biome. (C) 2003 Elsevier B.V. All rights reserved. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Calif State Univ Los Angeles, CEA, CREST, Los Angeles, CA 90032 USA. Calif State Univ Los Angeles, Dept Sci Biol, Los Angeles, CA 90032 USA. Univ Maryland, Joint Ctr Earth Syst Technol, Baltimore, MD 21201 USA. Univ Lethbridge, Dept Geog, Lethbridge, AB T1K 3M4, Canada. Univ Toronto, Dept Geog, Toronto, ON M5S 1A1, Canada. Univ Montana, Sch Forestry, NTSG, Missoula, MT 59812 USA. Woods Hole Res Ctr, Woods Hole, MA 02543 USA. Florida State Univ, Dept Meteorol, Tallahassee, FL 32306 USA. Jet Propuls Lab, Pasadena, CA USA. York Univ, Dept Phys & Astron, Toronto, ON M3J 2R7, Canada. Ball State Univ, Dept Geog, Muncie, IN 47306 USA. MATIS, GMME, Meteo France, CNRM, Toulouse, France. USDA ARS, Beltsville Agr Res Ctr, Hydrol & Remote Sensing Lab, Beltsville, MD 20705 USA. Univ Valladolid, Palencia, Spain. Canada Ctr Remote Sensing, Ottawa, ON, Canada. RP Huemmrich, KF (reprint author), NASA, Goddard Space Flight Ctr, Code 923-4, Greenbelt, MD 20771 USA. EM karl.huemmrich@gsfc.nasa.gov RI Gamon, John/A-2641-2014; Goetz, Scott/A-3393-2015; Zarco-Tejada, Pablo J./A-6874-2012 OI Gamon, John/0000-0002-8269-7723; Goetz, Scott/0000-0002-6326-4308; Zarco-Tejada, Pablo J./0000-0003-1433-6165 NR 131 TC 52 Z9 55 U1 0 U2 21 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 JAN 30 PY 2004 VL 89 IS 2 BP 139 EP 162 DI 10.1016/j.rse.2003.08.017 PG 24 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA 768RY UT WOS:000188589900001 ER PT J AU Kimball, JS McDonald, KC Frolking, S Running, SW AF Kimball, JS McDonald, KC Frolking, S Running, SW TI Radar remote sensing of the spring thaw transition across a boreal landscape SO REMOTE SENSING OF ENVIRONMENT LA English DT Article DE BOREAS; radar; freeze/thaw; NSCAT; phenology; boreal forest ID NASA SCATTEROMETER NSCAT; NORTHERN-HEMISPHERE; CARBON BALANCE; FOREST; LATITUDES; ECOSYSTEM; TERRAIN; GROWTH; FROZEN; SEASON AB The seasonal transition of the boreal forest between frozen and non-frozen conditions affects a number of ecosystem processes that cycle between winter dormant and summer active states. The relatively short K-u-band wavelength (2.14 cm) of the space-borne NASA scatterometer (NSCAT) is sensitive to changes in dielectric properties, associated with large-scale changes in the relative abundance and phase (frozen or thawed) of canopy and surface water. We used a temporal change detection analysis of NSCAT daily radar backscatter measurements to characterize the 1997 seasonal spring thaw transition period across the 10(6) km(2) BOREAS study region of central Canada. In the spring, air temperature transitions from frozen to non-frozen conditions and surface observations of seasonal snow cover depletion were generally coincident with decreases in radar backscatter of more than 2.9 dB, regardless of regional landcover characteristics. We used a temporal classification of NSCAT daily differences from 5-day smoothed backscatter values to derive three simple indices describing the initiation, primary event and completion of the spring thaw transition period. Several factors had a negative impact on the relative accuracy of NSCAT-based results, including periodic gaps in NSCAT daily time-series information and a large (i.e., >2 cm day(-1)) spring rainfall event. However, these results were generally successful in capturing the seasonal transition of the region from frozen to non-frozen conditions, based on comparisons with regional weather station network information. These results illustrate the potential for improved assessment of springtime phenology and associated ecosystem dynamics across high latitude regions, where field based and optical remote-sensing methods are substantially degraded by frequent cloud cover, low solar illumination and sparse surface weather station networks. (C) 2003 Elsevier Inc. All rights reserved. C1 Univ Montana, Flathead Lake Biol Stn, Polson, MT 59860 USA. Univ Montana, Sch Forestry, NTSG, Missoula, MT 59812 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ New Hampshire, Durham, NH 03824 USA. RP Kimball, JS (reprint author), Univ Montana, Flathead Lake Biol Stn, 311 Bio Stn Lane, Polson, MT 59860 USA. EM johnk@ntsg.umt.edu NR 44 TC 53 Z9 55 U1 0 U2 9 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 JAN 30 PY 2004 VL 89 IS 2 BP 163 EP 175 DI 10.1016/j.rse.2002.06.004 PG 13 WC Environmental Sciences; Remote Sensing; Imaging Science & Photographic Technology SC Environmental Sciences & Ecology; Remote Sensing; Imaging Science & Photographic Technology GA 768RY UT WOS:000188589900002 ER PT J AU Sun, WB Loeb, NG Kato, S AF Sun, WB Loeb, NG Kato, S TI Estimation of instantaneous TOA albedo at 670 nm over ice clouds from POLDER multidirectional measurements SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE multidirectional measurement; ice clouds; albedo; angular distribution model ID ANGULAR-DISTRIBUTION MODELS; EARTH RADIATION BUDGET; OF-ATMOSPHERE ALBEDO; ENERGY SYSTEM CERES; BIDIRECTIONAL REFLECTANCE; SCATTERING PROPERTIES; OPTICAL-PROPERTIES; SINGLE-SCATTERING; LIGHT-SCATTERING; CIRRUS AB [1] An algorithm that determines the 670-nm top-of-atmosphere (TOA) albedo of ice clouds over ocean using Polarization and Directionality of the Earth's Reflectance ( POLDER) multidirectional measurements is developed. A plane-parallel layer of ice cloud with various optical thicknesses and light scattering phase functions is assumed. For simplicity, we use a double Henyey-Greenstein phase function to approximate the volume-averaged phase function of the ice clouds. A multidirectional reflectance best-fit match between theoretical and POLDER reflectances is used to infer effective cloud optical thickness, phase function and TOA albedo. Sensitivity tests show that while the method does not provide accurate independent retrievals of effective cloud optical depth and phase function, TOA albedo retrievals are accurate to within similar to3% for both a single layer of ice clouds or a multilayer system of ice clouds and water clouds. When the method is applied to POLDER measurements and retrieved albedos are compared with albedos based on empirical angular distribution models (ADMs), zonal albedo differences are generally smaller than similar to 3%. When albedos are compared with those on the POLDER-I ERB and Cloud product, the differences can reach similar to 15% at small solar zenith angles. C1 Hampton Univ, Ctr Atmospher Sci, Hampton, VA 23668 USA. RP Sun, WB (reprint author), NASA, Langley Res Ctr, Mail Stop 420, Hampton, VA 23681 USA. EM w.sun@larc.nasa.gov; n.g.loeb@larc.nasa.gov; s.kato@larc.nasa.gov NR 41 TC 3 Z9 3 U1 1 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JAN 29 PY 2004 VL 109 IS D2 AR D02210 DI 10.1029/2003JD003801 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 772XD UT WOS:000188867200002 ER PT J AU Burchill, JK Knudsen, DJ Bock, BJJ Pfaff, RF Wallis, DD Clemmons, JH Bounds, SR Stenbaek-Nielsen, H AF Burchill, JK Knudsen, DJ Bock, BJJ Pfaff, RF Wallis, DD Clemmons, JH Bounds, SR Stenbaek-Nielsen, H TI Core ion interactions with BB ELF, lower hybrid, and Alfven waves in the high-latitude topside ionosphere SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article DE core ion heating; topside ionosphere; Alfven waves; BB ELF; lower hybrid solitary structures; TAI ID FREJA SATELLITE-OBSERVATIONS; PLASMA-WAVES; ENERGIZATION MECHANISMS; ACCELERATION MECHANISM; AURORAL REGION; PARTICLE; BURSTS; EMISSION; OUTFLOW; FIELD AB We present simultaneous observations of ion distribution functions and plasma waves in the high-latitude topside ionosphere (500-1000 km) near local midnight during substorm activation. Using a new instrument, the Suprathermal Ion Imager (SII), we are able to explore two-dimensional ion distribution functions with unprecedented resolution in time (93 s(-1)) and energy, focusing on the lowest-energy core (<1 eV) population and suprathermal extensions thereof. The GEODESIC sounding rocket flew through regions containing broadband extremely low frequency ( BB ELF) waves, large-amplitude Alfven waves, and lower-hybrid solitary structures (LHSS), all of which have been shown previously to correlate with ion heating. However, GEODESIC detected heating only in association with LHSS. Ion distributions in and near LHSS showed acceleration in the direction transverse to <(B)over right arrow>(0) (TAI) with temperatures as high as 5-10 eV, appearing in regions 65 +/- 25 m across. TAI were centered on much smaller structures (similar to20 m across) of depleted plasma density and enhanced perpendicular electric fields from 0.1 to 10 kHz, consistent with observations from previous rocket flights. Also in agreement with previous findings, we find two distinct ion populations inside LHSS. The dominant population is composed of unheated, isotropic "core" Maxwellian ions having temperatures comparable to the surrounding ambient plasma, while roughly 10% of the plasma density corresponds to the TAI at pitch angles of 90 +/- 5degrees. We argue that the TAI associated with LHSS is consistent with bulk heating of the core ions, and we describe two scenarios that can lead to the observed two-temperature distributions. The BB ELF wave emissions were correlated with LHSS heating at short scales and anticorrelated with auroral electron precipitation at large scales. The GEODESIC instruments observed no large-scale ion heating in association with BB ELF waves. Similarly, no ion heating was detected in the presence of large-amplitude, short perpendicular wavelength Alfven waves. C1 Univ Calgary, Dept Phys & Astron, Calgary, AB T2N 1N4, Canada. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Aerosp Corp, Los Angeles, CA 90009 USA. Univ Iowa, Dept Phys, Iowa City, IA 52242 USA. Univ Alaska, Inst Geophys, Fairbanks, AK 99775 USA. Magnametrics, Ottawa, ON K1H 7A9, Canada. RP Burchill, JK (reprint author), Univ Calgary, Dept Phys & Astron, 2500 Univ Dr, Calgary, AB T2N 1N4, Canada. EM burchill@phys.ucalgary.ca RI Pfaff, Robert/F-5703-2012; OI Pfaff, Robert/0000-0002-4881-9715; Clemmons, James/0000-0002-5298-5222 NR 39 TC 18 Z9 18 U1 0 U2 3 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9380 EI 2169-9402 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD JAN 28 PY 2004 VL 109 IS A1 AR A01219 DI 10.1029/2003JA010073 PG 15 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 772YG UT WOS:000188870000004 ER PT J AU Jensen, E Pfister, L AF Jensen, E Pfister, L TI Transport and freeze-drying in the tropical tropopause layer SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE clouds; water vapor; dehydration ID STRATOSPHERIC WATER-VAPOR; CIRRUS CLOUDS; KELVIN WAVES; RADIATIVE IMPACTS; UPPER TROPOSPHERE; AEROSOL; ICE; TEMPERATURE; DYNAMICS; THIN AB We use a Lagrangian, one-dimensional cloud model to simulate ice cloud formation and dehydration along trajectories in the tropical tropopause layer (TTL). Time-height curtains of temperature along the trajectory paths are extracted from meteorological analyses. The temperatures are adjusted near the tropopause such that the spatial average cold point temperature matches tropical radiosonde measurements. Temperature perturbations due to Kelvin waves, Rossby gravity waves, and high-frequency gravity waves are superimposed. The cloud model tracks the growth and sedimentation of individual ice crystals. Ice number densities in the cloud simulations without waves range from <0.001 to similar to 0.2 cm(-3); when clouds form, they dehydrate the air but generally do not reduce the water vapor mixing ratio down to ice saturation. Wave-driven temperature perturbations result in higher cloud frequencies and cause higher ice number densities (>1 cm(-3)) and smaller crystals (1-10 mum radius), resulting in less sedimentation but still effective dehydration overall. Inclusion of wave-driven temperature oscillations decreases the final TTL H2O mixing ratio somewhat primarily because the wave perturbations decrease the tropical average cold point tropopause temperature by similar to0.75 K. Ultimately, air rising through the TTL is effectively dehydrated with or without wave perturbations. In general, the model results suggest that the final water vapor mixing ratios are primarily controlled by the minimum temperatures encountered by parcels and that they are relatively insensitive to factors such as the wave-driven temperature variability, the supersaturation threshold for ice nucleation, and the rate of ascent through the tropopause layer. However, the frequency and geographical distribution of cloud formation is very sensitive to these parameters. On average, the clouds dehydrate the air along trajectories down to mixing ratios similar to10-40% higher than the temperature minimum saturation mixing ratio. The simulations predict efficient freeze-drying of air by cloud formation within the TTL: For the December-January 1995/1996 period simulated the average final H2O mixing ratios at the tropopause (370-380 K potential temperature) range from 2.5 to 3.2 ppmv. These values are somewhat lower than the estimates of the stratospheric water vapor entry value from satellite and in situ measurements; hence an additional source of water (such as injection by deep convection) may be required to explain the observed tropical tropopause humidity. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP NASA, Ames Res Ctr, MS 245-4, Moffett Field, CA 94035 USA. EM ejensen@sky.arc.nasa.gov; pfister@mindego.arc.nasa.gov RI McGill, Matthew/D-8176-2012 NR 50 TC 150 Z9 150 U1 6 U2 12 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 JAN 27 PY 2004 VL 109 IS D2 AR D02207 DI 10.1029/2003JD004022 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 772XB UT WOS:000188866900009 ER PT J AU Sparks, L Komjathy, A Mannucci, AJ AF Sparks, L Komjathy, A Mannucci, AJ TI Sudden ionospheric delay decorrelation and its impact on the Wide Area Augmentation System (WAAS) SO RADIO SCIENCE LA English DT Article DE ionosphere; GPS; WAAS AB In the absence of selective availability, the ionosphere represents the largest source of positioning error for single-frequency users of the Global Positioning System (GPS). In differential GPS systems such as the Wide Area Augmentation System (WAAS), vertical ionospheric delays are modeled at regularly spaced intervals in geographic latitude and longitude. The broadcast bound on the error at each of these points is designated the grid ionospheric vertical error (GIVE). Higher performance standards planned for future implementations of WAAS require a reduction in the magnitude of the GIVE broadcast under nominal conditions. Achieving this reduction depends upon a better understanding of the decorrelation of ionospheric delay, in both space and time. In this paper we focus on temporal decorrelation. We report a methodology for assessing the impact on WAAS posed by a sudden increase in the level of ionospheric disturbance. The methodology is based upon forming an estimate of the probability P-D that a WAAS user will confront a sudden increase in the level of ionospheric disturbance following a period of relative calm. We have determined a limiting upper bound of P-D to be 4 x 10(-7), which lies well within the margin needed to meet WAAS integrity requirements. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Sparks, L (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM lawrence.sparks@jpl.nasa.gov RI Mannucci, Anthony/A-1349-2007 OI Mannucci, Anthony/0000-0003-2391-8490 NR 7 TC 8 Z9 8 U1 0 U2 1 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 JAN 27 PY 2004 VL 39 IS 1 AR RS1S13 DI 10.1029/2002RS002845 PG 8 WC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications SC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications GA 772YQ UT WOS:000188870900004 ER PT J AU Liao, XZ Zhu, YT Qiu, YM Uhl, D Xu, HF AF Liao, XZ Zhu, YT Qiu, YM Uhl, D Xu, HF TI Quantum dot/substrate interaction in InAs/In0.53Ga0.47As/InP(001) SO APPLIED PHYSICS LETTERS LA English DT Article ID DOTS; ISLANDS; EPITAXY; SEGREGATION; ENRICHMENT; CRYSTALS; GROWTH; LAYER; GAAS; GE AB InAs quantum dots grown on In0.53Ga0.47As/InP(001) substrate by low-pressure metalorganic chemical vapor deposition were investigated using high-angle annular dark-field imaging. Results suggest significant mass transport of mainly the large-sized component (InAs) from the In0.53Ga0.47As substrate to InAs quantum dots, an unexpected process that increases the system strain energy. The amount of the transported mass increases with quantum dot size. Two monolayers of GaAs inserted between InAs islands and the InGaAs substrate appears to block or at least effectively slow down this mass transport process. (C) 2004 American Institute of Physics. C1 Los Alamos Natl Lab, Los Alamos, NM 87545 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ New Mexico, Dept Earth & Planetary Sci, Albuquerque, NM 87131 USA. RP Liao, XZ (reprint author), Los Alamos Natl Lab, POB 1663, Los Alamos, NM 87545 USA. EM xzliao@lanl.gov RI Zhu, Yuntian/B-3021-2008; Liao, Xiaozhou/B-3168-2009 OI Zhu, Yuntian/0000-0002-5961-7422; Liao, Xiaozhou/0000-0001-8565-1758 NR 20 TC 5 Z9 5 U1 0 U2 1 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 JAN 26 PY 2004 VL 84 IS 4 BP 511 EP 513 DI 10.1063/1.1642754 PG 3 WC Physics, Applied SC Physics GA 765XN UT WOS:000188316500019 ER PT J AU Okong'o, NA Bellan, J AF Okong'o, NA Bellan, J TI Consistent large-eddy simulation of a temporal mixing layer laden with evaporating drops. Part 1. Direct numerical simulation, formulation and a priori analysis SO JOURNAL OF FLUID MECHANICS LA English DT Article ID SUBGRID-SCALE MODELS; MACH-NUMBER TURBULENCE; FREE JET; FLOWS; DISPERSION; PARTICLES; VELOCITY; CHANNEL AB Large-eddy simulation (LES) models are presented and evaluated on a database obtained from direct numerical simulation (DNS) of a three-dimensional temporal mixing layer with evaporating drops. The gas-phase equations are written in an Eulerian frame for two perfect gas species (carrier gas and vapour emanating from the drops), while the liquid-phase equations are written in a Lagrangian frame. The effect of drop evaporation on the gas phase is considered through mass, momentum and energy source terms. The DNS database consists of transitional states attained by layers with different initial Reynolds numbers and initial liquid-phase mass loadings. Budgets of the LES equations at the transitional states show that, for the mass loadings considered, the filtered source terms (FSTs) are smaller than the resolved inviscid terms and some subgrid scale (SGS) terms, but larger than the resolved viscous stress, heat flux and mass flux terms. The irreversible entropy production (i.e. the dissipation) expression for a two-phase flow with phase change is derived, showing that the dissipation contains contributions due to viscous stresses, heat and species-mass fluxes, and source terms. For both the DNS and filtered flow fields at transition, the two leading contributions are found to be the dissipation due to the energy source term and that due to the chemical potential of the mass source. Therefore, the modelling effort is focused on both the SGS fluxes and the FSTs in the LES equations. The FST models considered are applicable to LES in which the grid is coarser than the DNS grid and, consistently, 'computational' drops represent the DNS physical drops. Because the unfiltered flow field is required for the computation of the source terms, but would not be available in LES, it was approximated using the filtered flow field or the filtered flow field augmented by corrections based on the SGS variances. All of the FST models were found to overestimate DNS-field FSTs, with the relative error of modelling the unfiltered flow field compared to the error of using computational drops showing a complex dependence on filter width and number of computational drops. For modelling the SGS fluxes and (where possible) SGS variances, constant-coefficient Smagorinsky, gradient and scale-similarity models were assessed on the DNS database, and calibrated coefficients were statistically equivalent when computed on single-phase or two-phase flows. The gradient and scale-similarity models showed excellent correlation with the SGS quantities. An a posteriori study is proposed to evaluate the impact of the studied models on the flow-field development, so as to definitively assess their suitability for LES with evaporating drops. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Bellan, J (reprint author), CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. EM Josette.Bellan@jpl.nasa.gov NR 42 TC 62 Z9 62 U1 0 U2 10 PU CAMBRIDGE UNIV PRESS PI NEW YORK PA 40 WEST 20TH ST, NEW YORK, NY 10011-4211 USA SN 0022-1120 J9 J FLUID MECH JI J. Fluid Mech. PD JAN 25 PY 2004 VL 499 BP 1 EP 47 DI 10.1017/S0022112003007018 PG 47 WC Mechanics; Physics, Fluids & Plasmas SC Mechanics; Physics GA 809LP UT WOS:000220638500001 ER PT J AU van Aalst, MK van den Broek, MMP Bregman, A Bruhl, C Steil, B Toon, GC Garcelon, S Hansford, GM Jones, RL Gardiner, TD Roelofs, GJ Lelieveld, J Crutzen, PJ AF van Aalst, MK van den Broek, MMP Bregman, A Bruhl, C Steil, B Toon, GC Garcelon, S Hansford, GM Jones, RL Gardiner, TD Roelofs, GJ Lelieveld, J Crutzen, PJ TI Trace gas transport in the 1999/2000 Arctic winter: comparison of nudged GCM runs with observations SO ATMOSPHERIC CHEMISTRY AND PHYSICS LA English DT Article ID HALOGEN OCCULTATION EXPERIMENT; DOPPLER-SPREAD PARAMETERIZATION; GENERAL-CIRCULATION MODEL; CHEMISTRY-CLIMATE MODEL; SEMI-LAGRANGIAN TRANSPORT; WAVE MOMENTUM DEPOSITION; MIDDLE-ATMOSPHERE; STRATOSPHERIC CH4; GREENHOUSE-GAS; POLAR VORTEX AB We have compared satellite and balloon observations of methane (CH4) and hydrogen fluoride (HF) during the Arctic winter 1999/2000 with results from the MA-ECHAM4 middle atmospheric general circulation model (GCM). For this purpose, the meteorology in the model was nudged towards ECMWF analyses. This nudging technique is shown to work well for this middle atmospheric model, and offers good opportunities for the simulation of chemistry and transport processes. However, caution must be used inside the polar vortex, particularly late in the winter. The current study focuses on transport of HF and CH4, initialized with satellite measurements from the HALOE instrument aboard the UARS satellite. We have compared the model results with HALOE data and balloon measurements throughout the winter, and analyzed the uncertainties associated with tracer initialization, boundary conditions and the passive tracer assumption. This comparison shows that the model represents some aspects of the Arctic vortex well, including relatively small-scale features. However, while profiles outside the vortex match observations well, the model underestimates HF and overestimates CH4 concentrations inside the vortex, particularly in the middle stratosphere. This problem is also evident in a comparison of vortex descent rates based upon vortex average tracer profiles from MA-ECHAM4, and various observations. This could be due to an underestimate of diabatic subsidence in the model, or due to too much mixing between vortex and non-vortex air. C1 Inst Marine & Atmospher Res, Utrecht, Netherlands. Space Res Org Netherlands SRON, Utrecht, Netherlands. Royal Netherlands Meteorol Inst, NL-3730 AE De Bilt, Netherlands. Max Planck Inst Chem, D-55128 Mainz, Germany. CALTECH, Jet Prop Lab, Pasadena, CA USA. Univ Cambridge, Cambridge, England. Natl Phys Lab, Teddington TW11 0LW, Middx, England. RP van Aalst, MK (reprint author), Inst Marine & Atmospher Res, Utrecht, Netherlands. EM aalst@phys.uu.nl RI Crutzen, Paul/F-6044-2012; Lelieveld, Johannes/A-1986-2013; OI Jones, Roderic /0000-0002-6761-3966 NR 52 TC 15 Z9 15 U1 0 U2 4 PU COPERNICUS GESELLSCHAFT MBH PI GOTTINGEN PA BAHNHOFSALLEE 1E, GOTTINGEN, 37081, GERMANY SN 1680-7316 J9 ATMOS CHEM PHYS JI Atmos. Chem. Phys. PD JAN 23 PY 2004 VL 4 BP 81 EP 93 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 771FR UT WOS:000188775400003 ER PT J AU Bauer, SE Balkanski, Y Schulz, M Hauglustaine, DA Dentener, F AF Bauer, SE Balkanski, Y Schulz, M Hauglustaine, DA Dentener, F TI Global modeling of heterogeneous chemistry on mineral aerosol surfaces: Influence on tropospheric ozone chemistry and comparison to observations SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE heterogeneous chemistry; mineral dust; tropospheric ozone ID GENERAL-CIRCULATION MODEL; SAHARAN DUST; AIRBORNE OBSERVATIONS; OPTICAL-THICKNESS; REACTIVE UPTAKE; IMPACT; OXIDES; HNO3; PARTICLES; SIMULATION AB [1] Mineral aerosols can affect gas phase chemistry in the troposphere by providing reactive sites for heterogeneous reactions. We present here a global modeling study of the influence of mineral dust on the tropospheric photochemical cycle. This work is part of the Mineral Dust and Tropospheric Chemistry (MINATROC) project, which focussed on measurement campaigns, laboratory experiments, and integrative modeling. The laboratory experiments provide uptake coefficients for chemical species on mineral aerosol surfaces, which are used to compute the heterogeneous reaction rates in the model. The field measurements at Mount Cimone, northern Italy, provide trace gas and aerosol measurements during a Saharan dust episode and are used to evaluate the model. The simulations include the reactions between mineral dust aerosols and the gas-phase species O-3, HNO3, NO3, and N2O5. Under the conditions for the year 2000 the model simulates a decrease in global tropospheric ozone mass by about 5% due to the heterogeneous reactions on dust aerosols. The most important heterogeneous reaction is the uptake of HNO3 on the dust surface, whereby the direct uptake of ozone on dust is not important in atmospheric chemistry. The comparison of the model results to observations indicates that the model simulates well the aerosol mass transported into the Mediterranean during the dust events and the arrival of all major dust events that were observed during a 7 month period. The decrease in ozone concentration during dust events is better simulated by the model when the heterogeneous reactions are included. C1 CEA, CNRS, Lab Sci Climat & Envrionm, F-91191 Gif Sur Yvette, France. Commiss European Communities, Joint Res Ctr, Inst Environm & Sustainabil, I-21020 Ispra, Italy. RP Balkanski, Y (reprint author), Columbia Univ, NASA, Goddard Inst Space Studies, Earth Inst, 2880 Broadway, New York, NY 10025 USA. EM sbauer@giss.nasa.gov; balkanski@cea.fr; schulz@cea.fr; hauglustaine@cea.fr; frank.dentener@jrc.it RI Balkanski, Yves/A-6616-2011; Bauer, Susanne/P-3082-2014; Schulz, Michael/A-6930-2011 OI Balkanski, Yves/0000-0001-8241-2858; Schulz, Michael/0000-0003-4493-4158 NR 62 TC 129 Z9 133 U1 4 U2 29 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 JAN 23 PY 2004 VL 109 IS D2 AR D02304 DI 10.1029/2003JD003868 PG 17 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 769WH UT WOS:000188672400005 ER PT J AU Gao, RS Popp, PJ Fahey, DW Marcy, TP Herman, RL Weinstock, EM Baumgardner, DG Garrett, TJ Rosenlof, KH Thompson, TL Bui, PT Ridley, BA Wofsy, SC Toon, OB Tolbert, MA Karcher, B Peter, T Hudson, PK Weinheimer, AJ Heymsfield, AJ AF Gao, RS Popp, PJ Fahey, DW Marcy, TP Herman, RL Weinstock, EM Baumgardner, DG Garrett, TJ Rosenlof, KH Thompson, TL Bui, PT Ridley, BA Wofsy, SC Toon, OB Tolbert, MA Karcher, B Peter, T Hudson, PK Weinheimer, AJ Heymsfield, AJ TI Evidence that nitric acid increases relative humidity in low-temperature cirrus clouds SO SCIENCE LA English DT Article ID IN-SITU MEASUREMENTS; ICE PARTICLES; CRYSTAL-GROWTH; FREEZING RESISTANCE; UPPER TROPOSPHERE; VAPOR GROWTH; HNO3; STRATOSPHERE; NUCLEATION; ADSORPTION AB In situ measurements of the relative humidity with respect to ice (RHi) and of nitric acid (HNO3) were made in both natural and contrail cirrus clouds in the upper troposphere. At temperatures lower than 202 kelvin, RHi values show a sharp increase to average values of over 130% in both cloud types. These enhanced RHi values are attributed to the presence of a new class of HNO3-containing ice particles (Delta-ice). We propose that surface HNO3 molecules prevent the ice/vapor system from reaching equilibrium by a mechanism similar to that of freezing point depression by antifreeze proteins. Delta-ice represents a new link between global climate and natural and anthropogenic nitrogen oxide emissions. Including Delta-ice in climate models will alter simulated cirrus properties and the distribution of upper tropospheric water vapor. C1 NOAA, Aeron Lab, Boulder, CO 80305 USA. Univ Colorado, Cooperat Inst Res Environm Sci, Boulder, CO 80309 USA. Univ Colorado, Program Atmospher & Ocean Sci, Atmospher & Space Phys Lab, Boulder, CO 80309 USA. Univ Colorado, Dept Chem & Biochem, Boulder, CO 80309 USA. NASA, Jet Prop Lab, Pasadena, CA 91109 USA. Harvard Univ, Atmospher Res Project, Cambridge, MA 02138 USA. Harvard Univ, Dept Earth & Planetary Sci, Cambridge, MA 02138 USA. Univ Nacl Autonoma Mexico, Ctr Ciencias Atmosfera, Mexico City 04510, DF, Mexico. Univ Utah, Dept Meteorol, Salt Lake City, UT 84112 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Natl Ctr Atmospher Res, Div Atmospher Chem, Boulder, CO 80307 USA. Deutsch Zentrum Luft & Raumfahrt, Inst Phys Atmosphare, Wessling, Germany. ETH, Lab Atmospharenphys, CH-8093 Zurich, Switzerland. RP Gao, RS (reprint author), NOAA, Aeron Lab, Boulder, CO 80305 USA. EM rgao@al.noaa.gov RI Heymsfield, Andrew/E-7340-2011; Herman, Robert/H-9389-2012; Gao, Ru-Shan/H-7455-2013; Karcher, Bernd/D-5325-2014; Rosenlof, Karen/B-5652-2008; Fahey, David/G-4499-2013 OI Herman, Robert/0000-0001-7063-6424; Karcher, Bernd/0000-0003-0278-4980; Rosenlof, Karen/0000-0002-0903-8270; Fahey, David/0000-0003-1720-0634 NR 62 TC 84 Z9 84 U1 1 U2 20 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 JAN 23 PY 2004 VL 303 IS 5657 BP 516 EP 520 DI 10.1126/science.1091255 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 765XM UT WOS:000188316400036 PM 14739457 ER PT J AU Sun, G Palazzolo, AB Provenza, A Montague, G AF Sun, G Palazzolo, AB Provenza, A Montague, G TI Detailed ball bearing model for magnetic suspension auxiliary service SO JOURNAL OF SOUND AND VIBRATION LA English DT Article AB Catcher bearings (CBs) provide backup protection for rotating machines with active magnetic bearings (AMBs). The CBs are required in the event of an AMB failure or high transient loads. Numerical simulations of a rotor drop on CBs in flywheel energy storage system are conducted with a detailed CB model which includes a Hertzian load-deflection relationship between mechanical contacts, speed-and-preload-dependent bearing stiffness due to centrifugal force, and a Palmgren's drag friction torque. The transient simulation results show the rotor shaft response variations with the design parameters: shaft/bearing friction coefficients, axial preload, support damping of damper liner, and side loads from magnetic bearings. The results reveal that friction coefficients, support damping, and side loads are critical parameters to satisfy CB design objectives and prevent backward (super) whirl. (C) 2003 Elsevier Science Ltd. All rights reserved. C1 Texas A&M Univ, Dept Mech Engn, College Stn, TX 77843 USA. NASA, USA, Cleveland, OH 44135 USA. RP Sun, G (reprint author), Texas A&M Univ, Dept Mech Engn, 100 Engn Phys Bldg, College Stn, TX 77843 USA. EM sungy@tamu.edu NR 20 TC 26 Z9 28 U1 1 U2 9 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 JAN 22 PY 2004 VL 269 IS 3-5 BP 933 EP 963 DI 10.1016/S0022-460X(03)00207-4 PG 31 WC Acoustics; Engineering, Mechanical; Mechanics SC Acoustics; Engineering; Mechanics GA 764EU UT WOS:000188195100026 ER PT J AU Pan, XP Shao, M Kulkarni, SR AF Pan, XP Shao, M Kulkarni, SR TI A distance of 133-137 parsecs to the Pleiades star cluster SO NATURE LA English DT Article ID PALOMAR TESTBED INTERFEROMETER; III STELLAR INTERFEROMETER; SPECTROSCOPIC BINARIES; LUNAR OCCULTATIONS; PARALLAXES; ORBIT AB Nearby ' open' clusters of stars ( those that are not gravitationally bound) have played a crucial role in the development of stellar astronomy because, as a consequence of the stars having a common age, they provide excellent natural laboratories to test theoretical stellar models. Clusters also play a fundamental part in determining distance scales. The satellite Hipparcos(1) surprisingly found that an extensively studied open cluster - the Pleiades ( also known as the Seven Sisters) - had a distance of D = 118 +/- 4 pc ( refs 2, 3), about ten per cent smaller than the accepted value(4-6). The discrepancy generated a spirited debate because the implication(7) was that either current stellar models were incorrect by a surprising amount or Hipparcos was giving incorrect distances. Here we report the orbital parameters of the bright double star Atlas in the Pleiades, using long- baseline optical/ infrared interferometry. From the data we derive a firm lower bound of D > 127 pc, with the most likely range being 133 < D < 137 pc. Our result reaffirms the fidelity of current stellar models. C1 CALTECH, Opt Observ 105 24, Pasadena, CA 91125 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Kulkarni, SR (reprint author), CALTECH, Opt Observ 105 24, Pasadena, CA 91125 USA. EM srk@anju.caltech.edu NR 27 TC 64 Z9 66 U1 0 U2 3 PU NATURE PUBLISHING GROUP PI LONDON PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD JAN 22 PY 2004 VL 427 IS 6972 BP 326 EP 328 DI 10.1038/nature02296 PG 3 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 765KE UT WOS:000188266200033 PM 14737161 ER PT J AU Cummings, DAT Irizarry, RA Huang, NE Endy, TP Nisalak, A Ungchusak, K Burke, DS AF Cummings, DAT Irizarry, RA Huang, NE Endy, TP Nisalak, A Ungchusak, K Burke, DS TI Travelling waves in the occurrence of dengue haemorrhagic fever in Thailand SO NATURE LA English DT Article ID TIME-SERIES ANALYSIS; PARENTERAL INFECTION; AEDES-AEGYPTI; DISEASE; TEMPERATURE; DYNAMICS; VIRUSES; PREY AB Dengue fever is a mosquito- borne virus that infects 50 - 100 million people each year(1). Of these infections, 200,000 - 500,000 occur as the severe, life- threatening form of the disease, dengue haemorrhagic fever ( DHF)(2). Large, unanticipated epidemics of DHF often overwhelm health systems(3). An understanding of the spatial - temporal pattern of DHF incidence would aid the allocation of resources to combat these epidemics. Here we examine the spatial - temporal dynamics of DHF incidence in a data set describing 850,000 infections occurring in 72 provinces of Thailand during the period 1983 to 1997. We use the method of empirical mode decomposition(4) to show the existence of a spatial - temporal travelling wave in the incidence of DHF. We observe this wave in a three- year periodic component of variance, which is thought to reflect host pathogen population dynamics(5,6). The wave emanates from Bangkok, the largest city in Thailand, moving radially at a speed of 148 km per month. This finding provides an important starting point for detecting and characterizing the key processes that contribute to the spatial - temporal dynamics of DHF in Thailand. C1 Johns Hopkins Bloomberg Sch Publ Hlth, Dept Int Hlth, Baltimore, MD 21205 USA. Johns Hopkins Bloomberg Sch Publ Hlth, Dept Biostat, Baltimore, MD 21205 USA. Johns Hopkins Univ, Dept Geog & Environm Engn, Baltimore, MD 21218 USA. NASA, Goddard Space Flight Ctr, Lab Hydrospher Proc, Oceans & Ice Branch, Greenbelt, MD 20771 USA. USA, Med Res Inst Infect Dis, Div Virol, Ft Detrick, MD 21702 USA. Armed Forces Res Inst Med Sci, Dept Virol, Bangkok 10400, Thailand. Minist Publ Hlth, Bur Epidemiol, Nonthaburi, Thailand. RP Burke, DS (reprint author), Johns Hopkins Bloomberg Sch Publ Hlth, Dept Int Hlth, Baltimore, MD 21205 USA. EM dburke@jhsph.edu OI /0000-0002-5704-8094 NR 24 TC 238 Z9 247 U1 5 U2 32 PU NATURE PUBLISHING GROUP PI LONDON PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD JAN 22 PY 2004 VL 427 IS 6972 BP 344 EP 347 DI 10.1038/nature02225 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 765KE UT WOS:000188266200039 PM 14737166 ER PT J AU Wang, XC Chao, Y AF Wang, XC Chao, Y TI Simulated Sea Surface Salinity variability in the tropical Pacific SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID MODEL AB Sea Surface Salinity (SSS) variability from a hindcast run of an oceanic general circulation model (OGCM) forced by daily NCEP-NCAR reanalysis from 1990 to 2001 is analyzed. The purpose is to test the capability of the model in terms of the salinity simulation and provide insights for the future SSS observation from space. With daily forcing, the model can reproduce SSS change of the tropical Pacific on different time scales by comparing with the Tropical Atmosphere Ocean (TAO) mooring observation. Our model results show that the western tropical Pacific is a large variability center on different time scales. On the interannual time scale, the standard deviation of SSS in the region could reach 0.5 practical salinity unit (psu). However, the eastern tropical Pacific shows relatively weak SSS variability (0.1 psu). On the intraannual time scale ( 60 - 360 days), the SSS variability in the western tropical Pacific is around 0.2 psu. The model SSS variability for the intraseasonal time scale ( 30 - 60 days) has a magnitude around 0.1 psu and tends to elongate along the latitudes of large meridional SSS gradient. On time scale shorter than 30 days, the model SSS variability center is near the equator and has a magnitude less than 0.1 psu. Relevance to the upcoming salinity satellite mission is discussed. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Wang, XC (reprint author), CALTECH, Jet Prop Lab, M-S 300-323,4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM xiao@pacific.jpl.nasa.gov; yi.chao@jpl.nasa.gov NR 10 TC 36 Z9 37 U1 0 U2 2 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JAN 21 PY 2004 VL 31 IS 2 AR L02302 DI 10.1029/2003GL018146 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 769VX UT WOS:000188671400001 ER PT J AU Harstad, K Bellan, J AF Harstad, K Bellan, J TI High-pressure binary mass diffusion coefficients for combustion applications SO INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH LA English DT Article ID SUPERCRITICAL CARBON-DIOXIDE; FLUID CHROMATOGRAPHY; TRANSPORT-PROPERTIES; DENSE GASES; BENZENE; NAPHTHALENE; MIXTURES; ACETONE; CO2; DERIVATIVES AB A scaling for binary mass diffusion coefficients is developed using a corresponding states expression based on kinetic theory. The scaling is used to form nondimensional diffusion coefficients. Available data for high-pressure binary mass diffusion coefficients related to combustion applications are processed in conjunction with the scaling, leading to recommended scaled coefficient fits as a function of the reduced density. Data uncertainties and possible interpretation difficulties are examined. A means for comprehensive diffusion coefficient modeling over a broad (3 orders of magnitude) pressure range is suggested. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Bellan, J (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM Josette.Bellan@jpl.nasa.gov NR 44 TC 18 Z9 18 U1 0 U2 4 PU AMER CHEMICAL SOC PI WASHINGTON PA 1155 16TH ST, NW, WASHINGTON, DC 20036 USA SN 0888-5885 J9 IND ENG CHEM RES JI Ind. Eng. Chem. Res. PD JAN 21 PY 2004 VL 43 IS 2 BP 645 EP 654 DI 10.1021/ie0304558 PG 10 WC Engineering, Chemical SC Engineering GA 764VT UT WOS:000188227200041 ER PT J AU Abbott, B Abbott, R Adhikari, R Ageev, A Allen, B Amin, R Anderson, SB Anderson, WG Araya, M Armandula, H Asiri, F Aufmuth, P Aulbert, C Babak, S Balasubramanian, R Ballmer, S Barish, BC Barker, D Barker-Patton, C Barnes, M Barr, B Barton, MA Bayer, K Beausoleil, R Belczynski, K Bennett, R Berukoff, SJ Betzwieser, J Bhawal, B Bilenko, IA Billingsley, G Black, E Blackburn, K Bland-Weaver, B Bochner, B Bogue, L Bork, R Bose, S Brady, PR Braginsky, VB Brau, JE Brown, DA Brozek, S Bullington, A Buonanno, A Burgess, R Busby, D Butler, WE Byer, RL Cadonati, L Cagnoli, G Camp, JB Cantley, CA Cardenas, L Carter, K Casey, MM Castiglione, J Chandler, A Chapsky, J Charlton, P Chatterji, S Chen, Y Chickarmane, V Chin, D Christensen, N Churches, D Colacino, C Coldwell, R Coles, M Cook, D Corbitt, T Coyne, D Creighton, JDE Creighton, TD Crooks, DRM Csatorday, P Cusack, BJ Cutler, C D'Ambrosio, E Danzmann, K Davies, R Daw, E DeBra, D Delker, T DeSalvo, R Dhurandar, S Diaz, M Ding, H Drever, RWP Dupuis, RJ Ebeling, C Edlund, J Ehrens, P Elliffe, EJ Etzel, T Evans, M Evans, T Fallnich, C Farnham, D Fejer, MM Fine, M Finn, LS Flanagan, E Freise, A Frey, R Fritschel, P Frolov, V Fyffe, M Ganezer, KS Giaime, JA Gillespie, A Goda, K Gonzalez, G Gossler, S Grandclement, P Grant, A Gray, C Gretarsson, AM Grimmett, D Grote, H Grunewald, S Guenther, M Gustafson, E Gustafson, R Hamilton, WO Hammond, M Hanson, J Hardham, C Harry, G Hartunian, A Heefner, J Hefetz, Y Heinzel, G Heng, IS Hennessy, M Hepler, N Heptonstall, A Heurs, M Hewitson, M Hindman, N Hoang, P Hough, J Hrynevych, M Hua, W Ingley, R Ito, M Itoh, Y Ivanov, A Jennrich, O Johnson, WW Johnston, W Jones, L Jungwirth, D Kalogera, V Katsavounidis, E Kawabe, K Kawamura, S Kells, W Kern, J Khan, A Killbourn, S Killow, CJ Kim, C King, C King, P Klimenko, S Kloevekorn, P Koranda, S Kotter, K Kovalik, J Kozak, D Krishnan, B Landry, M Langdale, J Lantz, B Lawrence, R Lazzarini, A Lei, M Leonhardt, V Leonor, I Libbrecht, K Lindquist, P Liu, S Logan, J Lormand, M Lubinski, M Luck, H Lyons, TT Machenschalk, B MacInnis, M Mageswaran, M Mailand, K Majid, W Malec, M Mann, F Marin, A Marka, S Maros, E Mason, J Mason, K Matherny, O Matone, L Mavalvala, N McCarthy, R McClelland, DE McHugh, M McNamara, P Mendell, G Meshkov, S Messenger, C Mitrofanov, VP Mitselmakher, G Mittleman, R Miyakawa, O Miyoki, S Mohanty, S Moreno, G Mossavi, K Mours, B Mueller, G Mukherjee, S Myers, J Nagano, S Nash, T Naundorf, H Nayak, R Newton, G Nocera, F Nutzman, P Olson, T O'Reilly, B Ottaway, DJ Ottewill, A Ouimette, D Overmier, H Owen, BJ Papa, MA Parameswariah, C Parameswariah, V Pedraza, M Penn, S Pitkin, M Plissi, M Pratt, M Quetschke, V Raab, F Radkins, H Rahkola, R Rakhmanov, M Rao, SR Redding, D Regehr, MW Regimbau, T Reilly, KT Reithmaier, K Reitze, DH Richman, S Riesen, R Riles, K Rizzi, A Robertson, DI Robertson, NA Robison, L Roddy, S Rollins, J Romano, JD Romie, J Rong, H Rose, D Rotthoff, E Rowan, S Rudiger, A Russell, P Ryan, K Salzman, I Sanders, GH Sannibale, V Sathyaprakash, B Saulson, PR Savage, R Sazonov, A Schilling, R Schlaufman, K Schmidt, V Schofield, R Schrempel, M Schutz, BF Schwinberg, P Scott, SM Searle, AC Sears, B Seel, S Sengupta, AS Shapiro, CA Shawhan, P Shoemaker, DH Shu, QZ Sibley, A Siemens, X Sievers, L Sigg, D Sintes, AM Skeldon, K Smith, JR Smith, M Smith, MR Sneddon, P Spero, R Stapfer, G Strain, KA Strom, D Stuver, A Summerscales, T Sumner, MC Sutton, PJ Sylvestre, J Takamori, A Tanner, DB Tariq, H Taylor, I Taylor, R Thorne, KS Tibbits, M Tilav, S Tinto, M Tokmakov, KV Torres, C Torrie, C Traeger, S Traylor, G Tyler, W Ugolini, D Vallisneri, M van Putten, M Vass, S Vecchio, A Vorvick, C Vyatchanin, SP Wallace, L Walther, H Ward, H Ware, B Watts, K Webber, D Weidner, A Weiland, U Weinstein, A Weiss, R Welling, H Wen, L Wen, S Whelan, JT Whitcomb, SE Whiting, BF Willems, PA Williams, PR Williams, R Willke, B Wilson, A Winjum, BJ Winkler, W Wise, S Wiseman, AG Woan, G Wooley, R Worden, J Yakushin, I Yamamoto, H Yoshida, S Zawischa, I Zhang, L Zotov, N Zucker, M Zweizig, J AF Abbott, B Abbott, R Adhikari, R Ageev, A Allen, B Amin, R Anderson, SB Anderson, WG Araya, M Armandula, H Asiri, F Aufmuth, P Aulbert, C Babak, S Balasubramanian, R Ballmer, S Barish, BC Barker, D Barker-Patton, C Barnes, M Barr, B Barton, MA Bayer, K Beausoleil, R Belczynski, K Bennett, R Berukoff, SJ Betzwieser, J Bhawal, B Bilenko, IA Billingsley, G Black, E Blackburn, K Bland-Weaver, B Bochner, B Bogue, L Bork, R Bose, S Brady, PR Braginsky, VB Brau, JE Brown, DA Brozek, S Bullington, A Buonanno, A Burgess, R Busby, D Butler, WE Byer, RL Cadonati, L Cagnoli, G Camp, JB Cantley, CA Cardenas, L Carter, K Casey, MM Castiglione, J Chandler, A Chapsky, J Charlton, P Chatterji, S Chen, Y Chickarmane, V Chin, D Christensen, N Churches, D Colacino, C Coldwell, R Coles, M Cook, D Corbitt, T Coyne, D Creighton, JDE Creighton, TD Crooks, DRM Csatorday, P Cusack, BJ Cutler, C D'Ambrosio, E Danzmann, K Davies, R Daw, E DeBra, D Delker, T DeSalvo, R Dhurandar, S Diaz, M Ding, H Drever, RWP Dupuis, RJ Ebeling, C Edlund, J Ehrens, P Elliffe, EJ Etzel, T Evans, M Evans, T Fallnich, C Farnham, D Fejer, MM Fine, M Finn, LS Flanagan, E Freise, A Frey, R Fritschel, P Frolov, V Fyffe, M Ganezer, KS Giaime, JA Gillespie, A Goda, K Gonzalez, G Gossler, S Grandclement, P Grant, A Gray, C Gretarsson, AM Grimmett, D Grote, H Grunewald, S Guenther, M Gustafson, E Gustafson, R Hamilton, WO Hammond, M Hanson, J Hardham, C Harry, G Hartunian, A Heefner, J Hefetz, Y Heinzel, G Heng, IS Hennessy, M Hepler, N Heptonstall, A Heurs, M Hewitson, M Hindman, N Hoang, P Hough, J Hrynevych, M Hua, W Ingley, R Ito, M Itoh, Y Ivanov, A Jennrich, O Johnson, WW Johnston, W Jones, L Jungwirth, D Kalogera, V Katsavounidis, E Kawabe, K Kawamura, S Kells, W Kern, J Khan, A Killbourn, S Killow, CJ Kim, C King, C King, P Klimenko, S Kloevekorn, P Koranda, S Kotter, K Kovalik, J Kozak, D Krishnan, B Landry, M Langdale, J Lantz, B Lawrence, R Lazzarini, A Lei, M Leonhardt, V Leonor, I Libbrecht, K Lindquist, P Liu, S Logan, J Lormand, M Lubinski, M Luck, H Lyons, TT Machenschalk, B MacInnis, M Mageswaran, M Mailand, K Majid, W Malec, M Mann, F Marin, A Marka, S Maros, E Mason, J Mason, K Matherny, O Matone, L Mavalvala, N McCarthy, R McClelland, DE McHugh, M McNamara, P Mendell, G Meshkov, S Messenger, C Mitrofanov, VP Mitselmakher, G Mittleman, R Miyakawa, O Miyoki, S Mohanty, S Moreno, G Mossavi, K Mours, B Mueller, G Mukherjee, S Myers, J Nagano, S Nash, T Naundorf, H Nayak, R Newton, G Nocera, F Nutzman, P Olson, T O'Reilly, B Ottaway, DJ Ottewill, A Ouimette, D Overmier, H Owen, BJ Papa, MA Parameswariah, C Parameswariah, V Pedraza, M Penn, S Pitkin, M Plissi, M Pratt, M Quetschke, V Raab, F Radkins, H Rahkola, R Rakhmanov, M Rao, SR Redding, D Regehr, MW Regimbau, T Reilly, KT Reithmaier, K Reitze, DH Richman, S Riesen, R Riles, K Rizzi, A Robertson, DI Robertson, NA Robison, L Roddy, S Rollins, J Romano, JD Romie, J Rong, H Rose, D Rotthoff, E Rowan, S Rudiger, A Russell, P Ryan, K Salzman, I Sanders, GH Sannibale, V Sathyaprakash, B Saulson, PR Savage, R Sazonov, A Schilling, R Schlaufman, K Schmidt, V Schofield, R Schrempel, M Schutz, BF Schwinberg, P Scott, SM Searle, AC Sears, B Seel, S Sengupta, AS Shapiro, CA Shawhan, P Shoemaker, DH Shu, QZ Sibley, A Siemens, X Sievers, L Sigg, D Sintes, AM Skeldon, K Smith, JR Smith, M Smith, MR Sneddon, P Spero, R Stapfer, G Strain, KA Strom, D Stuver, A Summerscales, T Sumner, MC Sutton, PJ Sylvestre, J Takamori, A Tanner, DB Tariq, H Taylor, I Taylor, R Thorne, KS Tibbits, M Tilav, S Tinto, M Tokmakov, KV Torres, C Torrie, C Traeger, S Traylor, G Tyler, W Ugolini, D Vallisneri, M van Putten, M Vass, S Vecchio, A Vorvick, C Vyatchanin, SP Wallace, L Walther, H Ward, H Ware, B Watts, K Webber, D Weidner, A Weiland, U Weinstein, A Weiss, R Welling, H Wen, L Wen, S Whelan, JT Whitcomb, SE Whiting, BF Willems, PA Williams, PR Williams, R Willke, B Wilson, A Winjum, BJ Winkler, W Wise, S Wiseman, AG Woan, G Wooley, R Worden, J Yakushin, I Yamamoto, H Yoshida, S Zawischa, I Zhang, L Zotov, N Zucker, M Zweizig, J TI Detector description and performance for the first coincidence observations between LIGO and GEO SO NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT LA English DT Article DE LIGO; gravitational wave; interterometer; observatory ID GRAVITATIONAL-WAVE DETECTOR; FABRY-PEROT CAVITY; FUSED-SILICA; EXCESS NOISE; INTERFEROMETER; LASER; SUSPENSION; ALIGNMENT; PENDULUM; SYSTEM AB For 17 days in August and September 2002, the LIGO and GEO interferometer gravitational wave detectors were operated in coincidence to produce their first data for scientific analysis. Although the detectors were still far from their design sensitivity levels, the data can be used to place better upper limits on the flux of gravitational waves incident on the earth than previous direct measurements. This paper describes the instruments and the data in some detail, as a companion to analysis papers based on the first data. (C) 2003 Elsevier B.V. All rights reserved. C1 Univ Tokyo, Inst Cosm Ray Res, Tokyo, Japan. Univ Coll Dublin, Dublin 2, Ireland. CALTECH, LIGO, Pasadena, CA 91125 USA. Stanford Univ, Stanford, CA 94305 USA. Univ Glasgow, Glasgow G12 8QQ, Lanark, Scotland. Hanford Observ, LIGO, Richland, WA 99352 USA. Univ Wales Coll Cardiff, Cardiff CF2 3YB, S Glam, Wales. Albert Einstein Inst, Max Planck Inst Gravitat Phys, D-14476 Golm, Germany. Univ Hannover, D-30167 Hannover, Germany. Univ Texas, Brownsville, TX 78520 USA. Southmost Coll, Brownsville, TX 78520 USA. Univ Florida, Gainesville, FL 32611 USA. Univ Wisconsin, Milwaukee, WI 53201 USA. MIT, LIGO, Cambridge, MA 02139 USA. Livingston Observ, LIGO, Livingston, LA 70504 USA. CALTECH, LIGO, Pasadena, CA 91125 USA. Moscow MV Lomonosov State Univ, Fac Phys, Moscow 119992, Russia. Louisiana Tech Univ, Ruston, LA 71272 USA. SE Louisiana Univ, Hammond, LA 70402 USA. Trinity Univ, San Antonio, TX 78212 USA. Univ Illes Balears, E-07071 Palma de Mallorca, Spain. Syracuse Univ, Syracuse, NY 13244 USA. Hobart & William Smith Coll, Geneva, NY 14456 USA. Salish Kootenai Coll, Pablo, MT 59855 USA. Fermilab Natl Accelerator Lab, Batavia, IL 60510 USA. Loyola Univ, New Orleans, LA 70118 USA. Natl Astron Observ, Tokyo 1818588, Japan. Univ Birmingham, Birmingham B15 2TT, W Midlands, England. Calif State Univ Dominguez Hills, Carson, CA 90747 USA. Cornell Univ, Ithaca, NY 14853 USA. Penn State Univ, University Pk, PA 16802 USA. CALTECH, Pasadena, CA 91125 USA. Interuniv Ctr Astron & Astrophys, Pune 411007, Maharashtra, India. Max Planck Inst Quantum Opt, D-85748 Garching, Germany. Australian Natl Univ, Canberra, ACT, Australia. Albert Einstein Inst, Max Planck Inst Gravitat Phys, D-30167 Hannover, Germany. Carleton Coll, Northfield, MN 55057 USA. Univ Michigan, Ann Arbor, MI 48109 USA. Louisiana State Univ, Baton Rouge, LA 70803 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Rochester, Rochester, NY 14627 USA. CALTECH, CaRT, Pasadena, CA 91125 USA. Univ Oregon, Eugene, OR 97403 USA. Washington State Univ, Pullman, WA 99164 USA. Northwestern Univ, Evanston, IL 60208 USA. RP Shoemaker, DH (reprint author), MIT, NW17-161,175 Albany Str, Cambridge, MA 02139 USA. EM dhs@ligo.mit.edu RI Sylvestre, Julien/A-8610-2009; Beausoleil, Raymond/C-5076-2009; McClelland, David/E-6765-2010; Schutz, Bernard/B-1504-2010; Casey, Morag/C-9703-2010; Rowan, Sheila/E-3032-2010; Strain, Kenneth/D-5236-2011; Raab, Frederick/E-2222-2011; Lueck, Harald/F-7100-2011; Freise, Andreas/F-8892-2011; Kawabe, Keita/G-9840-2011; Mitrofanov, Valery/D-8501-2012; Vyatchanin, Sergey/J-2238-2012; Allen, Bruce/K-2327-2012; Chen, Yanbei/A-2604-2013; Barker, David/A-5671-2013; Pitkin, Matthew/I-3802-2013; Liu, Sheng/K-2815-2013; van Putten, Maurice/F-5237-2011; Vecchio, Alberto/F-8310-2015; Finn, Lee Samuel/A-3452-2009; Ottaway, David/J-5908-2015; Ottewill, Adrian/A-1838-2016; Sigg, Daniel/I-4308-2015; Frey, Raymond/E-2830-2016; OI Sylvestre, Julien/0000-0001-8136-4348; McClelland, David/0000-0001-6210-5842; Strain, Kenneth/0000-0002-2066-5355; Lueck, Harald/0000-0001-9350-4846; Papa, M.Alessandra/0000-0002-1007-5298; Taylor, Ian/0000-0001-5040-0772; Zweizig, John/0000-0002-1521-3397; Aulbert, Carsten/0000-0002-1481-8319; Heurs, Michele/0000-0002-5577-2273; Tokmakov, Kirill/0000-0002-2808-6593; Allen, Bruce/0000-0003-4285-6256; Pitkin, Matthew/0000-0003-4548-526X; Vecchio, Alberto/0000-0002-6254-1617; Finn, Lee Samuel/0000-0002-3937-0688; Ottewill, Adrian/0000-0003-3293-8450; Sigg, Daniel/0000-0003-4606-6526; Frey, Raymond/0000-0003-0341-2636; Whelan, John/0000-0001-5710-6576 NR 48 TC 228 Z9 225 U1 2 U2 19 PU ELSEVIER SCIENCE BV PI AMSTERDAM PA PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS SN 0168-9002 J9 NUCL INSTRUM METH A JI Nucl. Instrum. Methods Phys. Res. Sect. A-Accel. Spectrom. Dect. Assoc. Equip. PD JAN 21 PY 2004 VL 517 IS 1-3 BP 154 EP 179 DI 10.1016/j.nima.2003.11.124 PG 26 WC Instruments & Instrumentation; Nuclear Science & Technology; Physics, Nuclear; Physics, Particles & Fields SC Instruments & Instrumentation; Nuclear Science & Technology; Physics GA 767ZJ UT WOS:000188503500015 ER PT J AU Molnar, SM Haiman, Z Birkinshaw, M Mushotzky, RF AF Molnar, SM Haiman, Z Birkinshaw, M Mushotzky, RF TI Constraints on the energy content of the universe from a combination of galaxy cluster observables SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmological parameters; cosmology : theory; galaxies : clusters : general ID X-RAY; COSMOLOGICAL PARAMETERS; HUBBLE-CONSTANT; DARK ENERGY; INTRACLUSTER MEDIUM; SCALING RELATIONS; SUPERNOVAE; EVOLUTION; PROBE; DISTANCE AB We demonstrate that constraints on cosmological parameters from the distribution of clusters as a function of redshift (dN/dz) are complementary to accurate angular diameter distance (D-A) measurements to clusters, and their combination significantly tightens constraints on the energy density content of the universe. The number counts can be obtained from X-ray and/or Sunyaev-Zel'dovich (SZ) effect surveys, and the angular diameter distances can be determined from deep observations of the intracluster gas using its thermal bremsstrahlung X-ray emission and the SZ effect. We combine constraints from simulated cluster number counts expected from a 12 deg(2) SZ cluster survey and constraints from simulated angular diameter distance measurements based on the X-ray/SZ method, assuming a statistical accuracy of 10% in the angular diameter distance determination of 100 clusters with redshifts less than 1.5. We find that Omega(m) can be determined within about 25%, Omega(Lambda) within 20%, and w within 16%. We show that combined dN/dz + D-A constraints can be used to constrain the different energy densities in the universe even in the presence of a few percent redshift dependent systematic error in D-A. We also address the question of how best to select clusters of galaxies for accurate diameter distance determinations. We show that the joint dN/dz + D-A constraints on cosmological parameters for a fixed target accuracy in the energy density parameters are optimized by selecting clusters with redshift upper cutoffs in the range 0.5 less than or similar to z less than or similar to 1. C1 Rutgers State Univ, Dept Phys & Astron, Piscataway, NJ 08854 USA. Columbia Univ, Dept Astron, New York, NY 10027 USA. Univ Bristol, Dept Phys, Bristol BS8 1TL, Avon, England. NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. RP Molnar, SM (reprint author), Rutgers State Univ, Dept Phys & Astron, 136 Frelinghuysen Rd, Piscataway, NJ 08854 USA. NR 44 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 JAN 20 PY 2004 VL 601 IS 1 BP 22 EP 27 DI 10.1086/380295 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 769NX UT WOS:000188657600002 ER PT J AU Cillis, AN Hartman, RC Bertsch, DL AF Cillis, AN Hartman, RC Bertsch, DL TI Stacking searches for gamma-ray emission above 100 MeV from radio and Seyfert galaxies SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : active; galaxies : Seyfert; gamma rays : observations ID EGRET OBSERVATIONS; CENTAURUS; BLAZARS; CATALOG AB The EGRET telescope on board Compton Gamma Ray Observatory detected more than 60 sources of high-energy gamma radiation associated with active galactic nuclei (AGNs). All but one of those belong to the blazar subclass; the only exception is the nearby radio galaxy Centaurus A. Since there is no obvious reason other than proximity to expect Cen A to be the only nonblazar AGN emitting in high-energy gamma rays, we have utilized the "stacking'' technique to search for emission above 100 MeV from two nonblazar AGN subclasses, radio galaxies and Seyfert galaxies. Maps of gamma-ray counts, exposure, and diffuse background have been created, then co-added in varying numbers based on sorts by redshift, 5 GHz flux density, and optical brightness, and finally tested for gamma-ray emission. No detection significance greater than 2 sigma has been found for any subclass, sorting parameter, or number of objects co-added. Monte Carlo simulations have also been performed to validate the technique and estimate the significance of the results. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Cillis, AN (reprint author), NASA, Goddard Space Flight Ctr, Code 661, Greenbelt, MD 20771 USA. NR 13 TC 16 Z9 16 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 JAN 20 PY 2004 VL 601 IS 1 BP 142 EP 150 DI 10.1086/380482 PN 1 PG 9 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 769NX UT WOS:000188657600013 ER PT J AU Bernstein, MP Ashbourn, SFM Sandford, SA Allamandola, LJ AF Bernstein, MP Ashbourn, SFM Sandford, SA Allamandola, LJ TI The lifetimes of nitriles (CN) and acids (COOH) during ultraviolet photolysis and their survival in space SO ASTROPHYSICAL JOURNAL LA English DT Article DE astrobiology; astrochemistry; ISM : molecules; molecular processes ID INTERSTELLAR GLYCINE; RADIATION-FIELD; AMINO-ACIDS; SEARCH; ICE; EVOLUTION; HYDROGEN; ORGANICS; CLOUDS AB Nitriles are one of the most common classes of molecules observed in the gas phase in space, with over a dozen having been positively identified in interstellar and circumstellar environments through the detection of their rotational transitions. Acids, in contrast, are much less common. In this paper we present laboratory data comparing the stability of two structurally related acid-nitrile pairs to ultraviolet (UV) photolytic destruction: acetic acid (CH(3)COOH) versus acetonitrile (CH(3)CN) and glycine (H(2)NCH(2)COOH) versus aminoacetonitrile (H(2)NCH(2)CN). We find that the nitriles are destroyed 10 and 5 times more slowly ( respectively) by UV photolysis than are the corresponding acids. This suggests that whatever their relative formation rates, acids may be less abundant than nitriles in interstellar environments in part because they are more rapidly destroyed by photolysis. The results of this infrared (IR) spectral matrix isolation study indicate that during the lifetime of a typical interstellar cloud, even in its darkest regions, a population of acids in the gas phase will likely be diminished by at least half. Since aminoacetonitrile is a precursor to the amino acid glycine, and far more stable, presolar aminoacetonitrile may be a contributor to the deuterium-enriched glycine detected in meteorites. It would clearly be informative to search for aminoacetonitrile ( the nitrile corresponding to glycine) in the regions where the amino acid glycine has been reported. C1 SETI Inst, Ctr Study Life Universe, Mountain View, CA 94043 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. SRI Int, Menlo Pk, CA 94025 USA. RP Bernstein, MP (reprint author), SETI Inst, Ctr Study Life Universe, 2035 Landings Dr, Mountain View, CA 94043 USA. NR 23 TC 53 Z9 53 U1 1 U2 16 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 JAN 20 PY 2004 VL 601 IS 1 BP 365 EP 370 DI 10.1086/380306 PN 1 PG 6 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 769NX UT WOS:000188657600030 ER PT J AU Cannizzo, JK Gehrels, N Vishniac, ET AF Cannizzo, JK Gehrels, N Vishniac, ET TI A numerical gamma-ray burst simulation using three-dimensional relativistic hydrodynamics: The transition from spherical to jetlike expansion SO ASTROPHYSICAL JOURNAL LA English DT Article DE gamma rays : bursts; hydrodynamics; methods : numerical; relativity; shock waves ID WIND INTERACTION-MODELS; AFTERGLOW LIGHT CURVES; CENTRAL-TYPE SCHEME; ENERGY RESERVOIR; BLAST WAVES; SHOCK; COLLAPSARS; EMISSION; DYNAMICS; FIREBALL AB We present the first unrestricted, three-dimensional relativistic hydrodynamical calculations of the blob of gas associated with the jet that produces a gamma-ray burst. We investigate the deceleration phase of the blob, which corresponds to the time when afterglow radiation is produced, concentrating on the transition in which the relativistic beaming gamma(-1) goes from being less than theta, where gamma is the bulk Lorentz factor and theta is the angular width of the jet, to gamma(-1) being greater than theta. We study the time-dependent evolution of the physical parameters associated with the jet, both parallel to the direction of motion and perpendicular to it. We calculate light curves for observers at varying angles with respect to the velocity vector of the blob, assuming optically thin emission that scales with the local pressure. Our main findings are that ( 1) gas ahead of the advancing blob does not accrete onto and merge with the blob material but rather flows around the blob, ( 2) the decay light curve steepens at a time corresponding roughly to gamma(-1) approximate to theta ( in accord with earlier studies), and ( 3) the rate of decrease of the forward component of momentum in the blob is well fitted by a simple model in which the gas in front of the blob exerts a drag force on the blob and the cross-sectional area of the blob increases quadratically with laboratory time ( or distance). C1 NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21210 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. EM cannizzo@stars.gsfc.nasa.gov; gehrels@lheapop.gsfc.nasa.gov; ethan@pha.jhu.edu RI Gehrels, Neil/D-2971-2012; OI Vishniac, Ethan/0000-0002-2307-3857 NR 60 TC 39 Z9 39 U1 0 U2 2 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 JAN 20 PY 2004 VL 601 IS 1 BP 380 EP 390 DI 10.1086/380436 PN 1 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 769NX UT WOS:000188657600032 ER PT J AU Brosius, JW White, SM AF Brosius, JW White, SM TI Close association of an extreme-ultraviolet sunspot plume with depressions in the sunspot radio emission SO ASTROPHYSICAL JOURNAL LA English DT Article DE Sun : corona; Sun : magnetic fields; Sun : radio radiation; Sun : transition region; Sun : UV radiation; sunspots ID SOLAR ACTIVE-REGION; CORONAL DIAGNOSTIC SPECTROMETER; X-RAY OBSERVATIONS; MAGNETIC-FIELDS; ATOMIC DATABASE; GYRORESONANCE EMISSION; RING STRUCTURE; WAVELENGTH; SPECTRUM; CHIANTI AB We obtained coordinated observations of the large sunspot in NOAA Region 8539 on 1999 May 9 and 13 with the Very Large Array and three instruments (CDS, EIT, MDI) aboard the Solar and Heliospheric Observatory satellite. The EUV observations reveal a plume in the sunspot umbra on both observing dates. The plume appears brightest in emission lines formed at temperatures between 1.6 x 10(5) and 5.0 x 10(5) K. Radio emission from the sunspot umbra is dominated by thermal gyroemission from the plume, which accounts for radio brightness temperatures < 1 x 10(6) K in the umbra on both dates, as well as umbral brightness temperature depressions in the 4.535 and 8.065 GHz observations on May 13. A compact 14.665 GHz source persists near the umbra/penumbra boundary during our observing period, indicating a long-lived, compact flux tube with coronal magnetic field strength of at least 1748 G. It occurs in a portion of the sunspot that appears very dark in EUV emission. C1 NASA, Goddard Space Flight Ctr, Catholic Univ Amer, Greenbelt, MD 20771 USA. Univ Maryland, Dept Astron, College Pk, MD 20742 USA. RP Brosius, JW (reprint author), NASA, Goddard Space Flight Ctr, Catholic Univ Amer, Code 682, Greenbelt, MD 20771 USA. NR 46 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 JAN 20 PY 2004 VL 601 IS 1 BP 546 EP 558 DI 10.1086/380394 PN 1 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 769NX UT WOS:000188657600047 ER PT J AU Deming, D Charbonneau, D Harrington, J AF Deming, D Charbonneau, D Harrington, J TI Spectroscopy of molecular hydrogen emission from KH 15D SO ASTROPHYSICAL JOURNAL LA English DT Article DE planetary systems : formation; planetary systems : protoplanetary disks; stars : pre-main-sequence ID T-TAURI STAR; BIPOLAR OUTFLOW; ECLIPSES; ENVIRONMENT; YOUNG; DISK AB We report infrared spectroscopy of the unusual eclipsing pre-main-sequence object KH 15D, obtained using NIRSPEC on Keck II. During eclipse, observations using low spectral resolution (lambda/deltalambda similar to 1000) reveal the presence of prominent molecular hydrogen emission in five lines near 2 mm. The relative line strengths are consistent with thermal excitation at T similar to 2800 +/- 300 K. Observations out of eclipse, at both low and high spectral resolution (lambda/deltalambda similar to 2 x 10(4)), show reduced contrast with the stellar continuum. The change in contrast for the strongest line, 1-0 S( 1), is consistent with an approximately constant emission line superposed on a variable stellar continuum. Emission in the 1-0 S(1) line is observed to extend by less than or equal to4" both east and west of the stellar point-spread function (PSF; greater than or similar to3000 AU). Observed at high spectral resolution, the velocity and the intensity structure of the 1-0 S(1) profile are both asymmetric. East of the stellar PSF (by 1."1-2."3) the emission is blueshifted (-63 km s(-1)) and has significantly greater intensity than the marginally redshifted component (+2 km s(-1), approximately consistent with zero) that dominates west of the stellar PSF. The spatial extent of the emission and the excitation temperature suggest shock excitation of ambient gas by a bipolar outflow from the star and/or the disk. However, it is difficult to account for the observed radial velocity unless the outflow axis is inclined significantly to the plane of the sky. C1 NASA, Goddard Space Flight Ctr, Planetary Syst Branch, Greenbelt, MD 20771 USA. CALTECH, Pasadena, CA 91125 USA. Cornell Univ, Ctr Radiophys & Space Res, Ithaca, NY 14853 USA. RP Deming, D (reprint author), NASA, Goddard Space Flight Ctr, Planetary Syst Branch, Code 693, Greenbelt, MD 20771 USA. EM ddeming@pop600.gsfc.nasa.gov; dc@caltech.edu; jh@oobleck.astro.cornell.edu RI Harrington, Joseph/E-6250-2011; OI Harrington, Joseph/0000-0002-8955-8531 NR 20 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 JAN 20 PY 2004 VL 601 IS 1 BP L87 EP L90 DI 10.1086/381739 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 769NZ UT WOS:000188657800023 ER PT J AU Choi, DI Brown, JD Imbiriba, B Centrella, J MacNeice, P AF Choi, DI Brown, JD Imbiriba, B Centrella, J MacNeice, P TI Interface conditions for wave propagation through mesh refinement boundaries SO JOURNAL OF COMPUTATIONAL PHYSICS LA English DT Article DE partial differential equations; computational techniques; finite difference methods; mesh generation and refinement; numerical relativity; gravitational waves ID PARTIAL-DIFFERENTIAL EQUATIONS; ADAPTIVE MESH; OVERLAPPING GRIDS; RELATIVITY AB We study the propagation of waves across fixed mesh refinement boundaries in linear and nonlinear model equations in 1-D and 2-D, and in the 3-D Einstein equations of general relativity. We demonstrate that using linear interpolation to set the data in guard cells leads to the production of reflected waves at the refinement boundaries. Implementing quadratic interpolation to fill the guard cells suppresses these spurious signals. (C) 2003 Elsevier B.V. All rights reserved. C1 NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, Greenbelt, MD 20771 USA. Univ Space Res Assoc, Lanham, MD 20706 USA. N Carolina State Univ, Dept Phys, Raleigh, NC 27695 USA. Univ Maryland, Dept Phys, College Pk, MD 20742 USA. Drexel Univ, Dept Phys, Philadelphia, PA 19104 USA. RP Choi, DI (reprint author), NASA, Goddard Space Flight Ctr, High Energy Astrophys Lab, 8800 Greenbelt Rd, Greenbelt, MD 20771 USA. EM choi@milkyway.gsfc.nasa.gov; david_brown@ncsu.edu; imbiriba@milkyway.gsfc.nasa.gov; jcentrel@milkyway.gsfc.nasa.gov; macneice@alfven.gsfc.nasa.gov RI MacNeice, Peter/F-5587-2012 NR 25 TC 23 Z9 23 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 J9 J COMPUT PHYS JI J. Comput. Phys. PD JAN 20 PY 2004 VL 193 IS 2 BP 398 EP 425 DI 10.1016/j.jcp.2003.07.036 PG 28 WC Computer Science, Interdisciplinary Applications; Physics, Mathematical SC Computer Science; Physics GA 765CM UT WOS:000188249600002 ER PT J AU Zhao, TXP Dubovik, O Smirnov, A Holben, BN Sapper, J Pietras, C Voss, KJ Frouin, R AF Zhao, TXP Dubovik, O Smirnov, A Holben, BN Sapper, J Pietras, C Voss, KJ Frouin, R TI Regional evaluation of an advanced very high resolution radiometer (AVHRR) two-channel aerosol retrieval algorithm SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE aerosol; retrieval; validation ID OPTICAL-PROPERTIES; ATMOSPHERIC AEROSOL; SIZE DISTRIBUTION; LIGHT-SCATTERING; NORTH-ATLANTIC; SOLAR SPECTRUM; COMPLEX INDEX; NOAA-AVHRR; DUST; SATELLITE AB Advanced Very High Resolution Radiometer (AVHRR) aerosol optical thickness retrieval over the ocean is one of the two existing sources of long-term global satellite aerosol measurements ( Total Ozone Mapping Spectrometer aerosol data set is the other). To make this 20-year historical data more useful for climate studies, the quality of the data ( or the performance of the retrieval algorithm) has to be systematically evaluated. In this paper, as a continuation of our previous global validation effort, we present regional validation results for an AVHRR independent two-channel aerosol retrieval algorithm by comparing the retrievals with observations from the Aerosol Robotic Network (AERONET). The bias and the random errors of the retrieval algorithm applied to NOAA14/ AVHRR observations were determined and documented for key aerosol types ( including biomass-burning, urban/industrial, desert dust, and marine). As a by-product of the validation, effective refractive indexes of the key aerosol types were also statistically determined through sensitivity analysis. The global and regional validations indicate that the new independent two-channel algorithm ( with a globally unified aerosol model) performs well in the sense of the global mean. However, improvements are necessary to make the retrieval sensitive to aerosol types and to capture aerosol regional variations. The results will facilitate the utilization of long-term AVHRR aerosol products in climate studies and will provide guidance for improving aerosol retrievals from future NOAA satellite instruments. C1 Colorado State Univ, Cooperat Inst Res Atmosphere, Ft Collins, CO 80523 USA. NOAA, NESDIS, ORA, WWBG, Camp Springs, MD 20746 USA. Univ Maryland Baltimore Cty, Goddard Earth Sci & Technol Ctr, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NASA, Goddard Space Flight Ctr, Terr Phys Lab, Greenbelt, MD 20771 USA. NOAA, NESDIS, OSDPD, Suitland, MD 20746 USA. NASA, Goddard Space Flight Ctr, SAIC, Greenbelt, MD 20771 USA. Univ Miami, Dept Phys, Coral Gables, FL 33124 USA. Univ Calif San Diego, Scripps Inst Oceanog, La Jolla, CA 92037 USA. RP Zhao, TXP (reprint author), Colorado State Univ, Cooperat Inst Res Atmosphere, Ft Collins, CO 80523 USA. EM xuepeng.zhao@noaa.gov RI Dubovik, Oleg/A-8235-2009; Smirnov, Alexander/C-2121-2009; Voss, Kenneth /A-5328-2013 OI Dubovik, Oleg/0000-0003-3482-6460; Smirnov, Alexander/0000-0002-8208-1304; Voss, Kenneth /0000-0002-7860-5080 NR 51 TC 9 Z9 9 U1 0 U2 6 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JAN 20 PY 2004 VL 109 IS D2 AR D02204 DI 10.1029/2003JD003817 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 769WE UT WOS:000188672100004 ER PT J AU Sittler, EC Johnson, RE Jurac, S Richardson, JD McGrath, M Crary, F Young, DT Nordholt, JE AF Sittler, EC Johnson, RE Jurac, S Richardson, JD McGrath, M Crary, F Young, DT Nordholt, JE TI Pickup ions at Dione and Enceladus: Cassini Plasma Spectrometer simulations SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article DE icy satellites; pickup ions; Dione; Enceladus; composition ID SATURNS E-RING; ENERGETIC CHARGED-PARTICLES; ELECTRON-IMPACT IONIZATION; ATOM ABSTRACTION REACTIONS; GAS-PHASE CHEMISTRY; CYCLOTRON WAVES; ICY SATELLITES; WATER ICE; INFRARED OBSERVATIONS; INNER MAGNETOSPHERE AB [1] Voyager images of the icy satellites of Saturn, Dione and Enceladus, suggest that they may have been geologically active and are not only composed of ice. Recent observations by the Hubble Space Telescope have shown the presence of ozone at both Dione and Rhea, which also implies the presence of molecular oxygen at these bodies. Observations of Ariel, Europa, Ganymede, and Callisto indicate the presence of CO(2), so its presence on the Saturnian satellites is also expected. The Cassini Plasma Spectrometer (CAPS) will provide the capability to determine the global composition of these bodies by measuring the pickup ions produced by the ionization of their sputter-produced atmospheres. We will present a model of these atmospheres and associated pickup ions and demonstrate CAPS ability to distinguish the freshly produced picked up ions from the ambient plasma. Such ions are expected to form a ring distribution that will have a uniquely different energy-angle dependence than the ambient plasma ions. In the case of Dione we expect the potential for a moderate strength interaction for which both Voyager 1 and Pioneer 11 spacecraft measured ion cyclotron waves centered on the Dione L shell and near the equatorial plane. SKR radio emissions also displayed emissions occurring at the orbital period of Dione which could indicate some intrinsic activity due to Dione. So again, something interesting may be going on at Dione. Since Enceladus, or material in orbit near Enceladus, may be the source of the E-ring, some surprises may be encountered during its close encounter with the Cassini spacecraft. In the case of Dione we will show that a wake pass at 500 km altitude is more than an order of magnitude better than an upstream pass at 500 km altitude. Pickup ion detection for minor ion species such as NH(3)(+) is possible for 500 km altitude wake pass but not for approximate to 500 km altitude upstream pass at closest approach. For navigation reasons a 100 km pass is not allowed. Therefore it is essential to have a wake pass to maximize the science return for a targeted flyby with Dione. The CAPS observations when combined with magnetometer, plasma wave and energetic particle observations will allow us to estimate the source of ions into Saturn's magnetosphere due to these two bodies and to characterize the nature of the interaction with Saturn's magnetosphere. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Virginia, Charlottesville, VA 22904 USA. MIT, Space Res Ctr, Cambridge, MA 02139 USA. Los Alamos Natl Lab, Space & Atmospher Sci Grp, Los Alamos, NM 87545 USA. Univ Michigan, Ann Arbor, MI 48109 USA. Los Alamos Natl Lab, Space & Atmospher Sci Grp, Los Alamos, NM 87545 USA. RP Sittler, EC (reprint author), NASA, Goddard Space Flight Ctr, Code 693,Greenbelt Rd, Greenbelt, MD 20771 USA. EM edward.c.sittler@nasa.gov; rej@virgini.edu; jurac@space.mit.edu; jdr@space.mit.edu; mcgrath@stsci.edu; fcrary@swri.edu; dyoung@swri.edu; jnordholt@lanl.gov NR 97 TC 26 Z9 26 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 JAN 20 PY 2004 VL 109 IS A1 AR A01214 DI 10.1029/2002JA009647 PG 22 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 769WV UT WOS:000188673500002 ER PT J AU Benson, RF Osherovich, VA AF Benson, RF Osherovich, VA TI Application of ionospheric topside-sounding results to magnetospheric physics and astrophysics SO RADIO SCIENCE LA English DT Article DE ionospheric topside sounding; magnetospheric radio emissions; plasma resonances; sounder-stimulated plasma emissions; plasma diagnostics; neutron star disk X-ray spectra ID DIFFUSE PLASMA RESONANCES; CYCLOTRON-HARMONIC WAVES; ELECTROSTATIC RESONANCES; KILOMETRIC RADIATION; DENSITY DISTRIBUTION; RADIO EMISSIONS; REGION; IMAGER; TORUS; FIELD AB [1] A brief review is presented to illustrate how the knowledge and experience gained from investigations of ionospheric topside-sounder ionograms has benefited scientific research beyond the ionosphere. In particular, to the interpretation of ( 1) natural radio emissions from space plasmas, ( 2) sounder-stimulated echoes and plasma emissions, and plasma diagnostics in planetary magnetospheres and ( 3) X-ray spectra of disks around neutron stars and black holes. The relevant data are from 60 satellite years of ionospheric topside-sounder operations by the four satellites of the International Satellites for Ionospheric Studies ( ISIS) program from 1963 through 1989. Not all of these data were reduced to ionograms on 35-mm film. An ongoing effort at the NASA Goddard Space Flight Center is producing digital topside-sounder ionograms directly from a selected subset of the original telemetry tapes. More than 300,000 digital ionograms are now in the National Space Science Data Center at the NASA GSFC (http://nssdc.gsfc.nasa.gov/space/ isis/isis-status.html). C1 NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. RP Benson, RF (reprint author), NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. EM robert.f.benson@nasa.gov NR 36 TC 5 Z9 5 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0048-6604 J9 RADIO SCI JI Radio Sci. PD JAN 20 PY 2004 VL 39 IS 1 AR RS1S28 DI 10.1029/2002RS002834 PG 6 WC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications SC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications GA 769WZ UT WOS:000188673900002 ER PT J AU Baker, JBH Greenwald, RA Ruohoniemi, JM Forster, M Paschmann, G Donovan, EF Tsyganenko, NA Quinn, JM Balogh, A AF Baker, JBH Greenwald, RA Ruohoniemi, JM Forster, M Paschmann, G Donovan, EF Tsyganenko, NA Quinn, JM Balogh, A TI Conjugate comparison of Super Dual Auroral Radar Network and Cluster electron drift instrument measurements of E x B plasma drift SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article DE Tsyganenko; field-aligned potential; inductive electric field; electrostatic mapping ID HIGH-LATITUDE CONVECTION; MAGNETIC-FIELD MODEL; SMALL-SCALE IRREGULARITIES; DAWN-DUSK ASYMMETRY; SOLAR-WIND; IONOSPHERIC CONVECTION; ALIGNED CURRENTS; F-REGION; MAGNETOSPHERE; SUBSTORM AB Much of our current understanding of magnetospheric electrodynamics is based on the assumption that magnetic field lines often behave as electrostatic equipotentials. This assumption has allowed hemispheric patterns of ionospheric convection to be interpreted in terms of the large-scale circulation of plasma in the magnetosphere. However, the extent to which the equipotential field-line assumption is justified for different regions of the magnetosphere has not been adequately explored, largely because of the sparseness of magnetospheric measurements. In this paper, a mathematical formalism is developed that allows conjugate magnetospheric and ionospheric measurements to be compared with each other using a model magnetic field. The technique is demonstrated during an event interval in which Super Dual Auroral Radar Network measurements of ionospheric plasma drift are mapped to the magnetosphere using the Tsyganenko T01 magnetic field model and compared with conjugate measurements from the Cluster spacecraft electron drift instrument. The degree of consistency between the conjugate measurements is discussed in terms of (1) the accuracy of the magnetic field model, (2) the validity of the assumption of equipotential magnetic field lines, and (3) the presence of inductive electric fields in the magnetosphere. It is also shown how conjugate plasma drift measurements can be used to identify small inaccuracies in the location of ionospheric foot points specified by the magnetic model. C1 Johns Hopkins Univ, Appl Phys Lab, Laurel, MD 20723 USA. Max Planck Inst Extraterr Phys, D-85741 Garching, Germany. Univ Calgary, Dept Phys & Astron, Calgary, AB T2N 1N4, Canada. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Space Res Assoc, Greenbelt, MD USA. Univ New Hampshire, Dept Phys, Durham, NH 03824 USA. Univ London Imperial Coll Sci Technol & Med, Dept Phys, London SW7 2AZ, England. RP Baker, JBH (reprint author), Johns Hopkins Univ, Appl Phys Lab, 11100 Johns Hopkins Rd, Laurel, MD 20723 USA. EM joseph.baker@jhuapl.edu RI Tsyganenko, Nikolai/J-7377-2012 OI Tsyganenko, Nikolai/0000-0002-5938-1579 NR 59 TC 9 Z9 9 U1 0 U2 5 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD JAN 17 PY 2004 VL 109 IS A1 AR A01209 DI 10.1029/2003JA009912 PG 20 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 765WX UT WOS:000188308300001 ER PT J AU Araujo-Pradere, EA Fuller-Rowell, TJ Bilitza, D AF Araujo-Pradere, EA Fuller-Rowell, TJ Bilitza, D TI Time Empirical Ionospheric Correction Model (STORM) response in IRI2000 and challenges for empirical modeling in the future SO RADIO SCIENCE LA English DT Article DE ionospheric modeling; empirical modeling; geomagnetic storms; ionospheric storms; validation ID INTERNATIONAL REFERENCE IONOSPHERE; GEOMAGNETIC STORMS; THERMOSPHERE; VALIDATION AB IRI2000 [Bilitza, 2001] now contains a geomagnetic activity dependence based on the Time Empirical Ionospheric Correction Model (STORM) [Araujo-Pradere and Fuller-Rowell, 2002; Araujo-Pradere et al., 2002]. The storm correction is driven by the previous time history of a(p) and is designed to scale the quiet time F layer critical frequency (f(o)F(2)) to account for storm-time changes in the ionosphere. The quality of the storm-time correction was recently evaluated by comparing the model with the observed ionospheric response during all the significant geomagnetic storms in 2000 and 2001. The model output was compared with the actual ionospheric response at 15 stations for each storm. These quantitative comparisons using statistical metrics showed that the model captures the decreases in electron density particularly well in summer and equinox conditions, but is not so good during winter conditions. To further assess the capabilities of the model, STORM has been compared in detail with observations during the Bastille Day storm in July 2000. This storm, considered to be on the extreme end of the statistical scale of storm magnitude, highlights two main areas were challenges remain for the empirical storm-time ionospheric model. The first is the rapid onset of the positive storm phase; the second is the regional composition changes that can affect one longitude sector at the expense of another for a particular storm. Both these challenges, although appreciated during the development of STORM, remain to be addressed. C1 NOAA, SEC, Boulder, CO 80303 USA. Raytheon ITSS, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Araujo-Pradere, EA (reprint author), NOAA, SEC, 325 Broadway R-SEC, Boulder, CO 80303 USA. EM araujo@noaa.gov NR 11 TC 20 Z9 20 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0048-6604 J9 RADIO SCI JI Radio Sci. PD JAN 16 PY 2004 VL 39 IS 1 AR RS1S24 DI 10.1029/2002RS002805 PG 8 WC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications SC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications GA 765XB UT WOS:000188308700001 ER PT J AU Bilitza, D Huang, XQ Reinisch, BW Benson, RF Hills, HK Schar, WB AF Bilitza, D Huang, XQ Reinisch, BW Benson, RF Hills, HK Schar, WB TI Topside Ionogram Scaler With True Height Algorithm (TOPIST): Automated processing of ISIS topside ionograms. SO RADIO SCIENCE LA English DT Article DE topside sounder; TOPIST; ionogram inversion; topside ionogram; ISIS ID ELECTRON-DENSITY PROFILES; DIGITAL IONOGRAMS; IONOSPHERE AB The United States/Canadian ISIS-1 and ISIS-2 satellites collected several million topside ionograms in the 1960s and 1970s with a multinational network of ground stations that provided good global coverage. However, processing of these ionograms into electron density profiles required time-consuming manual scaling of the traces from the analog ionograms, and as a result, only a few percent of the ionograms had been processed into electron density profiles. In recent years an effort began to digitize the analog recordings to prepare the ionograms for computerized analysis. As of November 2002, approximately 390,000 ISIS-1 and ISIS-2 digital topside-sounder ionograms have been produced. The Topside Ionogram Scaler With True Height Algorithm (TOPIST) program was developed for the automated scaling of the echo traces and for the inversion of these traces into topside electron density profiles. The program is based on the techniques that have been successfully applied in the analysis of ground-based Digisonde ionograms. The TOPIST software also includes an "editing option'' for manual scaling of the more difficult ionograms, which could not be scaled during the automated TOPIST run. TOPIST is now successfully scaling similar to60% of the ISIS ionograms, and the electron density profiles are available through the online archive of the National Space Science Data Center at ftp://nssdcftp.gsfc.nasa.gov/spacecraft_data/isis/topside_sounder. This data restoration effort is producing a unique global database of topside electron densities over more than one solar cycle, which will be of particular importance for improvements of topside ionosphere models, especially the International Reference Ionosphere. C1 GSFC, Raytheon ITSS, Greenbelt, MD 20771 USA. Univ Massachusetts, Ctr Atmospher Res, Lowell, MA 01854 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. QSS Inc, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. L3 Commun Anal Corp, Goddard Space Flight Ctr, Greenbelt, MD USA. RP Bilitza, D (reprint author), GSFC, Raytheon ITSS, Code 632, Greenbelt, MD 20771 USA. EM bilitza@pop600.gsfc.nasa.gov NR 13 TC 18 Z9 18 U1 1 U2 2 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 JAN 16 PY 2004 VL 39 IS 1 AR RS1S27 DI 10.1029/2002RS002840 PG 8 WC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications SC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications GA 765XB UT WOS:000188308700003 ER PT J AU Raine, A Ishikawa, SS Arce, E Lencz, T Knuth, KH Bihrle, S LaCasse, L Colletti, P AF Raine, A Ishikawa, SS Arce, E Lencz, T Knuth, KH Bihrle, S LaCasse, L Colletti, P TI Hippocampal structural asymmetry in unsuccessful psychopaths SO BIOLOGICAL PSYCHIATRY LA English DT Article DE hippocampus; psychopathy; MRI; trauma; neurodevelopment; asymmetry ID POSITRON-EMISSION-TOMOGRAPHY; CRIMINAL PSYCHOPATHS; FIBER DISTRIBUTIONS; VIOLENT OFFENDERS; BRAIN STRUCTURES; SCHIZOPHRENIA; BEHAVIOR; AGGRESSION; VOLUME; DISORDER AB Background: Structural and functional hippocampal abnormalities have been previously reported in institutionalized psychopathic and aggressive populations. This study assessed whether prior findings of a right greater than left (R > L) functional asymmetry in caught violent offenders generalize to the structural domain in unsuccesful, caught psychopaths. Methods: Left and right hippocampal volumes were assessed using structural magnetic resonance imaging (MRI) in 23 control subjects, 16 unsuccessful psychopaths, and 12 successful (uncaught) community psychopaths and transformed into standardized space. Results: Unsuccessful psychopaths showed an exaggerated structural hippocampal asymmetry (R > L) relative both to successful psychopaths and control subjects (p < .007) that was localized to the anterior region. This effect could not be explained by environmental and diagnostic confounds and constitutes the first brain imaging analysis of successful and unsuccessful psychopaths. Conclusions: Atypical anterior hippocampal asymmetries in in unsuccessful psychopaths may reflect an underlying neurodevelopmental abnormality that disrupts hippocampal-prefrontal circuitry, resulting in affect dysregulation, poor contextual fear conditioning, and insensitivity to cues predicting capture. C1 Univ So Calif, Dept Psychol, Los Angeles, CA 90089 USA. Univ So Calif, Program Neurosci, Los Angeles, CA 90089 USA. Hillside Hosp, N Shore Long Isl Jewish Hlth Syst, Dept Res, Glen Oaks, NY 11004 USA. NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Univ So Calif, Sch Med, Dept Radiol, Los Angeles, CA 90089 USA. RP Raine, A (reprint author), Univ So Calif, Dept Psychol, Seeley G Mudd Bldg 501, Los Angeles, CA 90089 USA. RI Lencz, Todd/J-3418-2014 OI Lencz, Todd/0000-0001-8586-338X FU NIMH NIH HHS [K02 MH01114-01, 5 R03 MH50940-02, 1 F32 MH12951-01] NR 70 TC 102 Z9 105 U1 8 U2 28 PU ELSEVIER SCIENCE INC PI NEW YORK PA 360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA SN 0006-3223 J9 BIOL PSYCHIAT JI Biol. Psychiatry PD JAN 15 PY 2004 VL 55 IS 2 BP 185 EP 191 DI 10.1016/S0006-3223(03)00727-3 PG 7 WC Neurosciences; Psychiatry SC Neurosciences & Neurology; Psychiatry GA 764GX UT WOS:000188200100012 PM 14732599 ER PT J AU Rafkin, SCR Michaels, TI Haberle, RM AF Rafkin, SCR Michaels, TI Haberle, RM TI Meteorological predictions for the Beagle 2 mission to Mars SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article AB A general circulation and mesoscale model are used to predict the weather at the Beagle 2 landing site. The afternoon high temperature predicted by the general circulation model varies from 237 to 243 K over the duration of the primary mission. The overnight low temperature is 193 K +/- 2 K. Near surface wind speeds remain below 15 ms(-1) at all times. The mesoscale model predicts a wind maximum at the top of the similar to4 km deep convective boundary layer. Gravity waves are evident in the free atmosphere above the PBL. The overall weather pattern is dominated by upslope and downslope circulations, but these are modulated by changes in the large-scale circulation. C1 SW Res Inst, Dept Space Studies, Boulder, CO 80302 USA. NASA, Ames Res Ctr, Div Space Sci, Moffett Field, CA 94035 USA. RP Rafkin, SCR (reprint author), SW Res Inst, Dept Space Studies, 1050 Walnut St,Suite 400, Boulder, CO 80302 USA. EM srafkin@boulder.swri.edu NR 9 TC 6 Z9 6 U1 0 U2 7 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JAN 15 PY 2004 VL 31 IS 1 AR L01703 DI 10.1029/2003GL018966 PG 5 WC Geosciences, Multidisciplinary SC Geology GA 765WA UT WOS:000188306300004 ER PT J AU Schaake, JC Duan, QY Koren, V Mitchell, KE Houser, PR Wood, EF Robock, A Lettenmaier, DP Lohmann, D Cosgrove, B Sheffield, J Luo, LF Higgins, RW Pinker, RT Tarpley, JD AF Schaake, JC Duan, QY Koren, V Mitchell, KE Houser, PR Wood, EF Robock, A Lettenmaier, DP Lohmann, D Cosgrove, B Sheffield, J Luo, LF Higgins, RW Pinker, RT Tarpley, JD TI An intercomparison of soil moisture fields in the North American land data assimilation system (NLDAS) SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE soil moisture; total water storage; land surface models ID MODEL; SCHEMES AB The multiple-agency/university North American Land Data Assimilation System (NLDAS) project is designed to provide enhanced soil and temperature initial conditions for numerical weather/climate prediction models. Currently, four land surface models (LSMs) are running in NLDAS both in retrospective mode and in real-time mode. All LSMs are driven by the same meteorologic forcing data and are initiated at the same time with the same relative soil wetness. This study intercompares these NLDAS soil moisture fields with each other and with available observations. The total water storage and the storage variability range are the foci of the study. The mean statistical properties and the spatial variation of these soil moisture fields along with their temporal change are investigated. Model soil moisture fields are compared to soil moisture observations in Illinois. The storage variability range in Arkansas-Red River basin is validated against a water balance diagnostic analysis using historical precipitation and streamflow data. There is better agreement between observed and simulated ranges of water storage variability than between observed and simulated amounts of total water storage. Significant differences are found between NLDAS-simulated soil moisture fields from the different models. Total water storage is found to be highly model dependent. There is better agreement between models in the water total water storage range than in the model values of total water storage. Total water storage ranges agree best in humid areas where variation in water storage is strongly driven by variation in precipitation. In very dry areas, agreement between simulated water storage ranges is weak because model differences have as much influence on water storage range as climate variability in these areas. Finally, the spin-up properties of the models and relationships between water storage properties and climate are investigated. The results of this study should provide important insights into the similarities and differences of the four LSMs in NLDAS. Differences in NLDAS soil moisture fields pose challenges to land surface modelers who intend to use soil moisture field from one model to initialize another model. C1 NOAA, Natl Weather Serv, Off Hydrol Dev, Silver Spring, MD 20910 USA. NOAA, Natl Weather Serv, Natl Ctr Environm Predict, Environm Modeling Ctr, Camp Springs, MD USA. NASA, Goddard Space Flight Ctr, Hydrol Sci Branch, Greenbelt, MD 20771 USA. Princeton Univ, Dept Civil & Environm Engn, Princeton, NJ 08544 USA. Rutgers State Univ, Dept Environm Sci, New Brunswick, NJ 08903 USA. Univ Washington, Dept Civil & Environm Engn, Seattle, WA 98195 USA. Sci Applicat Int Corp, Greenbelt, MD USA. NOAA, Natl Weather Serv, Natl Ctr Environm Predict, Climat Predict Ctr, Camp Springs, MD USA. Univ Maryland, Dept Meteorol, College Pk, MD 20742 USA. Natl Environm Satellite Data & Informat Serv, Off Res & Applicat, Camp Springs, MD USA. RP Schaake, JC (reprint author), NOAA, Natl Weather Serv, Off Hydrol Dev, Silver Spring, MD 20910 USA. RI Sheffield, Justin/A-6388-2008; Luo, Lifeng/C-8734-2009; Pinker, Rachel/F-6565-2010; Houser, Paul/J-9515-2013; lettenmaier, dennis/F-8780-2011; Duan, Qingyun/C-7652-2011; Robock, Alan/B-6385-2016 OI Houser, Paul/0000-0002-2991-0441; lettenmaier, dennis/0000-0003-3317-1327; Duan, Qingyun/0000-0001-9955-1512; NR 18 TC 55 Z9 55 U1 0 U2 11 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 JAN 15 PY 2004 VL 109 IS D1 AR D01S90 DI 10.1029/2002JD003309 PG 16 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 765WH UT WOS:000188307000001 ER PT J AU Gross, RS Fukumori, I Menemenlis, D Gegout, P AF Gross, RS Fukumori, I Menemenlis, D Gegout, P TI Atmospheric and oceanic excitation of length-of-day variations during 1980-2000 SO JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH LA English DT Article DE Earth rotation; length-of-day; oceanic angular momentum ID AXIAL ANGULAR-MOMENTUM; EARTHS ROTATION; GLOBAL OCEAN; SEA-LEVEL; SEASONAL BUDGET; POLAR MOTION; BOUSSINESQ APPROXIMATION; GENERAL-CIRCULATION; BOTTOM PRESSURE; MODEL AB [1] Although nontidal changes in the Earth's length-of-day on timescales of a few days to a few years are primarily caused by changes in the angular momentum of the zonal winds, other processes can be expected to cause the length-of-day to change as well. Here the relative contribution of upper atmospheric winds, surface pressure, oceanic currents, and ocean-bottom pressure to changing the length-of-day during 1980 - 2000 is evaluated using estimates of atmospheric angular momentum from the National Centers for Environmental Prediction/ National Center for Atmospheric Research reanalysis project, estimates of the angular momentum of the zonal winds in the upper atmosphere from the United Kingdom Meteorological Office, and estimates of oceanic angular momentum from the Estimating the Circulation and Climate of the Ocean consortium's simulation of the general circulation of the oceans. On intraseasonal timescales, atmospheric surface pressure, oceanic currents, and ocean-bottom pressure are found to be about equally important in causing the length-of-day to change, while upper atmospheric winds are found to be less important than these mechanisms. On seasonal timescales, the upper atmospheric winds are more important than the sum of currents and bottom pressure in causing the length-of-day to change and, except at the annual frequency, are even more important than surface pressure changes. On interannual timescales, oceanic currents and ocean-bottom pressure are found to be only marginally effective in causing the length-of-day to change. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Inst Phys Globe Strasbourg, F-67084 Strasbourg, France. RP Gross, RS (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM richard.gross@jpl.nasa.gov; if@pacific.jpl.nasa.gov; menemenlis@jpl.nasa.gov; pascal.gegout@eost.u-strasbg.fr NR 60 TC 44 Z9 49 U1 2 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 JAN 15 PY 2004 VL 109 IS B1 AR B01406 DI 10.1029/2003JB002432 PG 15 WC Geochemistry & Geophysics SC Geochemistry & Geophysics GA 765WQ UT WOS:000188307700001 ER PT J AU Bloemhof, EE AF Bloemhof, EE TI Anomalous intensity of pinned speckles at high adaptive correction SO OPTICS LETTERS LA English DT Article ID OPTICS; NOISE AB Ground-based optical searches for faint stellar or planetary companions about other stars may be limited by speckle noise, which is the rapid intensity fluctuations that are due to motions of remnant atmospheric speckles. Adaptive optics (AO) can reduce residual wave-front phase errors to low values, substantially reducing the unwanted power in the speckle halo. At high correction, however, the noise in the halo will be dominated by anomalously bright "pinned" speckles that have a number of unusual properties. They can have negative intensities and will appear in spatially antisymmetric patterns; they are spatially pinned to Airy rings and have zero mean in a sufficiently long integration. Some of these properties may be used to reduce the unanticipated effect of pinned speckles on companion searches, depending on details of the AO system. But, in short exposures, pinned speckles dominate speckle noise over much of the inner halo for Strehl ratios S as low as 0.6 and over much of the outer halo too as Strehl and deformable-mirror actuator densities increase. I show that these anomalously bright pinned speckles are not included in the traditional expression for speckle power in an image, (1 - S), on which sensitivity estimates of future high-performance AO systems have been based. (C) 2004 Optical Society of America C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Bloemhof, EE (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM eeb@huey.jpl.nasa.gov NR 10 TC 11 Z9 11 U1 0 U2 2 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 0146-9592 J9 OPT LETT JI Opt. Lett. PD JAN 15 PY 2004 VL 29 IS 2 BP 159 EP 161 DI 10.1364/OL.29.000159 PG 3 WC Optics SC Optics GA 761BU UT WOS:000187880100007 PM 14743997 ER PT J AU Davis, B Kim, E Piepmeier, JR AF Davis, B Kim, E Piepmeier, JR TI Stochastic modeling and generation of partially polarized or partially coherent electromagnetic waves SO RADIO SCIENCE LA English DT Article DE interferometry; polarimetry; remote sensing ID AIRCRAFT K-BAND; BRIGHTNESS TEMPERATURES; EARTH AB Many new Earth remote-sensing instruments are embracing both the advantages and added complexity that result from interferometric or fully polarimetric operation. To increase instrument understanding and functionality, a model of the signals these instruments measure is presented. A stochastic model is used as it recognizes the nondeterministic nature of any real-world measurements, while also providing a tractable mathematical framework. A wide-sense stationary, ergodic, Gaussian-distributed model structure is proposed. Temporal and spectral correlation measures provide a statistical description of the physical properties of coherence and polarization-state. From this relationship, the model is mathematically defined. A method of realizing the model (necessary for applications such as synthetic calibration-signal generation) is given, and computer simulation results are presented. The signals are constructed using the output of a multi-input, multi-output linear filter system, driven with white noise. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Davis, B (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. EM Ed.Kim@nasa.gov NR 18 TC 4 Z9 4 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0048-6604 J9 RADIO SCI JI Radio Sci. PD JAN 15 PY 2004 VL 39 IS 1 AR RS1001 DI 10.1029/2001RS002512 PG 8 WC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications SC Astronomy & Astrophysics; Geochemistry & Geophysics; Meteorology & Atmospheric Sciences; Remote Sensing; Telecommunications GA 765XA UT WOS:000188308600001 ER PT J AU Joiner, J Vasilkov, AP Flittner, DE Gleason, JF Bhartia, PK AF Joiner, J Vasilkov, AP Flittner, DE Gleason, JF Bhartia, PK TI Retrieval of cloud pressure and oceanic chlorophyll content using Raman scattering in GOME ultraviolet spectra SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE cloud; Raman; radiative transfer ID OZONE MONITORING EXPERIMENT; TROPOSPHERIC OZONE; GLOBAL OZONE; ABSORPTION-MEASUREMENTS; RAYLEIGH-SCATTERING; RADIATIVE-TRANSFER; TOMS MEASUREMENTS; UV MEASUREMENTS; WATER; ATMOSPHERE AB Reliable cloud pressure estimates are needed for accurate retrieval of ozone and other trace gases using satellite-borne hyperspectral backscatter ultraviolet (buv) instruments. The cloud pressures should be consistent with the assumptions made in the retrieval algorithms. Cloud pressure can be derived from buv instruments using the properties of rotational-Raman scattering (RRS) and absorption by O-2-O-2. Here we estimate cloud pressure using the concept of a Lambert-equivalent reflectivity (LER) surface that is also used in many trace gas retrieval algorithms. An LER cloud pressure (P-LER) algorithm is being developed for the ozone monitoring instrument (OMI) that will fly on NASA EOS Aura. As a demonstration, we apply the approach to data from the global ozone monitoring experiment (GOME) in the 355-400 nm spectral range. GOME has full spectral coverage in this range at relatively high spectral resolution with a very high signal-to-noise ratio. This allows for more accurate estimates of cloud pressure than were possible with its predecessors SBUV and TOMS. We also demonstrate for the first time the retrieval of oceanic chlorophyll content using oceanic Raman scattering in buv observations. We compare our retrieved P-LER with cloud top pressures, P-top, derived from the infrared ATSR-2 instrument on the same satellite for overcast situations. The findings confirm results from previous studies that showed retrieved P-LER from buv observations is systematically higher than IR-derived P-top. Simulations using Mie-scattering radiative transfer algorithms with O-2-O-2 absorption show that these differences can be explained by increased absorption within and below the cloud as well as between multiple cloud decks. C1 NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. Sci Syst & Applicat Inc, Lanham, MD 20706 USA. Univ Arizona, Cooperat Ctr Atmospher Sci & Technol, Tucson, AZ 85721 USA. NASA, Langley Res Ctr, Hampton, VA 23665 USA. RP Joiner, J (reprint author), NASA, Goddard Space Flight Ctr, Atmospheres Lab, Code 916, Greenbelt, MD 20771 USA. EM joiner@dao.gsfc.nasa.gov; alexander_vassilkov@sesda.com; d.e.flittner@larc.nasa.gov; gleason@redwing.gsfc.nasa.gov; bhartia@carioca.gsfc.nasa.gov RI Joiner, Joanna/D-6264-2012; Gleason, James/E-1421-2012 NR 49 TC 35 Z9 35 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 JAN 14 PY 2004 VL 109 IS D1 AR D01109 DI 10.1029/2003JD003698 PG 13 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 855MO UT WOS:000223977600001 ER PT J AU Khakoo, MA Vandeventer, P Childers, JG Kanik, I Fontes, CJ Bartschat, K Zeman, V Madison, DH Saxena, S Srivastava, R Stauffer, AD AF Khakoo, MA Vandeventer, P Childers, JG Kanik, I Fontes, CJ Bartschat, K Zeman, V Madison, DH Saxena, S Srivastava, R Stauffer, AD TI Electron impact excitation of the argon 3p(5)4s configuration: differential cross-sections and cross-section ratios SO JOURNAL OF PHYSICS B-ATOMIC MOLECULAR AND OPTICAL PHYSICS LA English DT Article ID HEAVY NOBLE-GASES; OPTICAL OSCILLATOR-STRENGTHS; PHOTON COINCIDENCE; ELASTIC-SCATTERING; ENERGY ELECTRONS; RESONANCE LINES; RARE-GASES; KRYPTON; AR; STATES AB New electron-impact differential cross-section (DCS) and DCS ratio measurements for the excitation of the four levels making up the 3p(5)4s configuration of argon are reported at incident electron energies of 14, 15, 17.5, 20, 30, 50 and 100 eV. These cross-sections were obtained using a conventional high resolution electron spectrometer. Elastic electron scattering from argon was used as a calibration standard. Electron-helium DCSs were used to determine the instrumental transmission of the spectrometer. Further checks of the relative shape of these DCS measurements were made using the method of gas mixtures (Ne mixed with Ar). We also present results from new calculations of these DCSs using the R-matrix method, the unitarized first-order many-body theory, the semi-relativistic distorted-wave Born approximation, and the relativistic distorted-wave method. Comparison with available experimental DCSs and DCS ratios is also presented. C1 Calif State Univ, Dept Phys, Fullerton, CA 92834 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Los Alamos Natl Lab, Appl Theoret & Computat Phys Div, Los Alamos, NM 87545 USA. Drake Univ, Dept Phys & Astron, Des Moines, IA 50311 USA. Univ Toronto, Dept Chem, Toronto, ON M5S 3H6, Canada. Univ Missouri, Dept Phys, Rolla, MO 65401 USA. Indian Inst Technol, Dept Phys, Roorkee 247667, Uttar Pradesh, India. York Univ, Dept Phys & Astron, Toronto, ON M3J 1P3, Canada. RP Khakoo, MA (reprint author), Calif State Univ, Dept Phys, Fullerton, CA 92834 USA. RI Bartschat, Klaus/I-2527-2012 NR 35 TC 49 Z9 50 U1 1 U2 5 PU IOP PUBLISHING LTD PI BRISTOL PA DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND SN 0953-4075 J9 J PHYS B-AT MOL OPT JI J. Phys. B-At. Mol. Opt. Phys. PD JAN 14 PY 2004 VL 37 IS 1 BP 247 EP 281 AR PII S0953-4075(04)67802-3 DI 10.1088/0953-4075/37/1/016 PG 35 WC Optics; Physics, Atomic, Molecular & Chemical SC Optics; Physics GA 773KU UT WOS:000188923600018 ER PT J AU Di Girolamo, P Marchese, R Whiteman, DN Demoz, BB AF Di Girolamo, P Marchese, R Whiteman, DN Demoz, BB TI Rotational Raman Lidar measurements of atmospheric temperature in the UV SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article AB Measurements of atmospheric temperature have been performed by the NASA Scanning Raman Lidar based on the application of the pure rotational Raman (RR) technique. These measurements represent to our knowledge the first successful lidar measurements of temperature using the RR technique in the UV region, where eye-safe concerns are far less stringent than in the visible and IR. While the system configuration was unoptimized for temperature measurements, nevertheless results were achieved that demonstrate the feasibility of the RR technique for meteorological and climatological applications. Based on 90 minutes data averaging, lidar measurements extend up to 23 km, with RMS deviation between lidar and simultaneous radiosondes not exceeding 1.2 K and average bias smaller than 0.5 K. Simulations reveal that the RR technique in the UV has the potential for providing accurate measurements throughout the troposphere, with appreciable improvement with respect to visible systems for daytime operation. C1 Univ Basilicata, DIFA, I-85100 Potenza, Italy. NASA, Goddard Space Flight Ctr, Mesoscale Atmospher Proc Branch, Greenbelt, MD 20771 USA. RP Di Girolamo, P (reprint author), Univ Basilicata, DIFA, I-85100 Potenza, Italy. EM digirolamo@unibas.it RI Demoz, Belay/N-4130-2014 NR 10 TC 52 Z9 52 U1 0 U2 7 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JAN 13 PY 2004 VL 31 IS 1 AR L01106 DI 10.1029/2003GL018342 PG 5 WC Geosciences, Multidisciplinary SC Geology GA 765WB UT WOS:000188306400001 ER PT J AU Fok, MC Moore, TE Collier, MR Tanaka, T AF Fok, MC Moore, TE Collier, MR Tanaka, T TI Neutral atom imaging of solar wind interaction with the Earth and Venus SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article DE neutral atom imaging; solar wind/magnetosphere interactions; solar wind/Venus interactions; atmospheric escape ID 3-DIMENSIONAL MHD SIMULATION; HOT HYDROGEN; OXYGEN; MARS AB Observations from the Low-Energy Neutral Atom (LENA) imager on the Imager for Magnetopause-to-Aurora Global Exploration (IMAGE) mission have emerged as a promising new tool for studying the solar wind interaction with the terrestrial magnetosphere. Strong LENA emissions are seen from the magnetosheath during magnetic storms, especially during high solar wind dynamic pressure when the magnetopause is strongly compressed and the magnetosheath penetrates deeply into the exosphere. Venus, unlike the Earth, has no intrinsic magnetic field, so the solar wind penetrates deeply and interacts directly with its upper atmosphere. Energy transfer processes enhance atomic escape and thus play a potentially important role in the evolution of the atmosphere. We have performed simulations of the solar wind interaction with both Earth and Venus and compared the results to LENA observations at the Earth. Low-energy neutral atom emissions from Venus are calculated based on the global MHD model of Tanaka. We found the simulated energetic neutral atom (ENA) emissions from Venus magnetosheath are comparable or greater than for the Earth. The Venus ionopause is clearly seen in the modeled oxygen ENA images. This simulation work demonstrates the feasibility of remotely sensing the Venusian solar wind interaction and resultant atmospheric escape using fast neutral atom imaging. C1 NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Greenbelt, MD 20771 USA. Kyushu Univ, Dept Earth & Planetary Sci, Higashi Ku, Fukuoka 8128581, Japan. RP Fok, MC (reprint author), NASA, Goddard Space Flight Ctr, Extraterr Phys Lab, Mail Code 692, Greenbelt, MD 20771 USA. EM mei-ching.h.fok@nasa.gov; thomas.e.moore@nasa.gov; mcollier@pop600.gsfc.nasa.gov; tatanaka@geo.kyushu-u.ac.jp RI Moore, Thomas/D-4675-2012; Fok, Mei-Ching/D-1626-2012; Collier, Michael/I-4864-2013 OI Moore, Thomas/0000-0002-3150-1137; Collier, Michael/0000-0001-9658-6605 NR 17 TC 13 Z9 13 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 JAN 13 PY 2004 VL 109 IS A1 AR A01206 DI 10.1029/2003JA010094 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 765WU UT WOS:000188308000003 ER PT J AU Hansen, J Nazarenko, L AF Hansen, J Nazarenko, L TI Soot climate forcing via snow and ice albedos SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article DE aerosols; air pollution; climate change; sea level ID ATMOSPHERIC AEROSOLS; BLACK CARBON; DIRTY SNOW; SURFACE; CHINA; ABSORPTION; RADIATION; CRYSTALS; SULFATE; MODEL AB Plausible estimates for the effect of soot on snow and ice albedos (1.5% in the Arctic and 3% in Northern Hemisphere land areas) yield a climate forcing of +0.3 W/m(2) in the Northern Hemisphere. The "efficacy" of this forcing is approximate to2, i.e., for a given forcing it is twice as effective as CO2 in altering global surface air temperature. This indirect soot forcing may have contributed to global warming of the past century, including the trend toward early springs in the Northern Hemisphere, thinning Arctic sea ice, and melting land ice and permafrost. If, as we suggest, melting ice and sea level rise define the level of dangerous anthropogenic interference with the climate system, then reducing soot emissions, thus restoring snow albedos to pristine high values, would have the double benefit of reducing global warming and raising the global temperature level at which dangerous anthropogenic interference occurs. However, soot contributions to climate change do not alter the conclusion that anthropogenic greenhouse gases have been the main cause of recent global warming and will be the predominant climate forcing in the future. C1 NASA, Goddard Inst Space Studies, New York, NY 10025 USA. Columbia Univ, Earth Inst, New York, NY 10025 USA. RP NASA, Goddard Inst Space Studies, New York, NY 10025 USA. EM jhansen@giss.nasa.gov NR 43 TC 554 Z9 602 U1 20 U2 175 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 JAN 13 PY 2004 VL 101 IS 2 BP 423 EP 428 DI 10.1073/pnas.2237157100 PG 6 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 764MJ UT WOS:000188210400004 PM 14699053 ER PT J AU Qiu, YM Uhl, D Keo, S AF Qiu, YM Uhl, D Keo, S TI Room-temperature continuous-wave operation of InAsSb quantum-dot lasers near 2 mu m based on (001) InP substrate SO APPLIED PHYSICS LETTERS LA English DT Article ID DASH LASERS; PERFORMANCE; WAVELENGTH; EMISSION AB Single-stack InAsSb self-assembled quantum-dot lasers based on (001) InP substrate have been grown by metalorganic vapor-phase epitaxy. The narrow ridge waveguide lasers lased at wavelengths near 2 mum up to 25 degreesC in continuous-wave operation. At room temperature, a differential quantum efficiency of 13% is obtained and the maximum output optical power reaches 3 mW per facet with a threshold current density of 730 A/cm(2). With increasing temperature the emission wavelength is extremely temperature stable, and a very low wavelength temperature sensitivity of 0.05 nm/degreesC is measured, which is even lower than that caused by the refractive index change. (C) 2004 American Institute of Physics. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Qiu, YM (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM yueming.qiu@jpl.nasa.gov NR 16 TC 41 Z9 41 U1 0 U2 1 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 JAN 12 PY 2004 VL 84 IS 2 BP 263 EP 265 DI 10.1063/1.1640467 PG 3 WC Physics, Applied SC Physics GA 761PC UT WOS:000187916300035 ER PT J AU Guo, SP Albin, S Rogowski, RS AF Guo, SP Albin, S Rogowski, RS TI Comparative analysis of Bragg fibers SO OPTICS EXPRESS LA English DT Article ID OPTICAL WAVE-GUIDE; ASYMPTOTIC ANALYSIS; PROPAGATION CHARACTERISTICS; PHOTONIC CRYSTAL; AIR-CORE; DISPERSION; TRANSMISSION; VECTOR; MODES AB In this paper, we compare three analysis methods for Bragg fibers, viz. the transfer matrix method, the asymptotic method and the Galerkin method. We also show that with minor modifications, the transfer matrix method is able to calculate exactly the leakage loss of Bragg fibers due to a finite number of H/L layers. This approach is more straightforward than the commonly used Chew's method. It is shown that the asymptotic approximation condition should be satisfied in order to get accurate results. The TE and TM modes, and the band gap structures are analyzed using Galerkin method. (C) 2004 Optical Society of America. C1 Old Dominion Univ, Dept Elect & Comp Engn, Photon Lab, Norfolk, VA 23529 USA. NASA, Langley Res Ctr, Nondestruct Evaluat Sci Branch, Hampton, VA 23681 USA. RP Guo, SP (reprint author), Old Dominion Univ, Dept Elect & Comp Engn, Photon Lab, Norfolk, VA 23529 USA. EM sguo@odu.edu NR 33 TC 61 Z9 65 U1 1 U2 8 PU OPTICAL SOC AMER PI WASHINGTON PA 2010 MASSACHUSETTS AVE NW, WASHINGTON, DC 20036 USA SN 1094-4087 J9 OPT EXPRESS JI Opt. Express PD JAN 12 PY 2004 VL 12 IS 1 BP 198 EP 207 DI 10.1364/OPEX.12.000198 PG 10 WC Optics SC Optics GA 766NT UT WOS:000188383000022 PM 19471526 ER PT J AU Lorimer, DR McLaughlin, MA Arzoumanian, Z Xilouris, KM Cordes, JM Lommen, AN Fruchter, AS Chandler, AM Backer, DC AF Lorimer, DR McLaughlin, MA Arzoumanian, Z Xilouris, KM Cordes, JM Lommen, AN Fruchter, AS Chandler, AM Backer, DC TI PSR J0609+2130: a disrupted binary pulsar? SO MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY LA English DT Article DE pulsars : general; pulsars : individual : J0609+2130 ID NEUTRON-STAR BINARIES; RADIO PULSARS; MAGNETIC-FIELDS; GALACTIC PLANE; SYSTEMS; DISCOVERY; EVOLUTION; SEARCHES; DECAY AB We report the discovery and initial timing observations of a 55.7-ms pulsar, J0609+2130, found during a 430-MHz drift-scan survey with the Arecibo radio telescope. With a spin-down rate of 3.1x10(-19) s s(-1) and an inferred surface dipole magnetic field of only 4.2x10(9) G, J0609+2130 has very similar spin parameters to the isolated pulsar J2235+1506 found by Camilo, Nice & Taylor. While the origin of these weakly magnetized isolated neutron stars is not fully understood, one intriguing possibility is that they are the remains of high-mass X-ray binary systems which were disrupted by the supernova explosion of the secondary star. C1 Univ Manchester, Jodrell Bank Observ, Macclesfield SK11 9DL, Cheshire, England. NASA, Goddard Space Flight Ctr, USRA, LHEA, Greenbelt, MD 20771 USA. Univ Virginia, Dept Astron, Charlottesville, VA 22903 USA. Cornell Univ, Dept Astron, Ithaca, NY 14853 USA. Franklin & Marshall Coll, Dept Phys & Astron, Lancaster, PA 17604 USA. Space Telescope Sci Inst, Baltimore, MD 21218 USA. CALTECH, Space Radiat Lab, Pasadena, CA 91125 USA. Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA. RP Lorimer, DR (reprint author), Univ Manchester, Jodrell Bank Observ, Macclesfield SK11 9DL, Cheshire, England. EM drl@jb.man.ac.uk NR 28 TC 29 Z9 29 U1 0 U2 0 PU OXFORD UNIV PRESS PI OXFORD PA GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND SN 0035-8711 EI 1365-2966 J9 MON NOT R ASTRON SOC JI Mon. Not. Roy. Astron. Soc. PD JAN 11 PY 2004 VL 347 IS 2 BP L21 EP L25 DI 10.1111/j.1365-2966.2004.07407.x PG 5 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 756EB UT WOS:000187451900003 ER PT J AU Breckinridge, JB Oppenheimer, BR AF Breckinridge, JB Oppenheimer, BR TI Polarization effects in reflecting coronagraphs for white-light applications in astronomy SO ASTROPHYSICAL JOURNAL LA English DT Article DE instrumentation : miscellaneous; planetary systems; polarization ID OPTICAL ANISOTROPY; THIN-FILMS AB The properties of metal thin films have been largely overlooked in discussions of the technical limitations and problems that arise in the field of direct detection of exoplanets. Here, polarization properties and anisotropy properties of highly reflecting thin metal films are examined within the context of the requirements for the ultra low-scattered-light system performance of coronagraphs applied to space and ground-based high-contrast, white-light astronomy. Wavelength-dependent optical constants for highly reflecting thin metal films, taken from the literature, are used to calculate the polarization-dependent transmissivity of a typical coronagraph. The effects of degraded performance on the astronomical science are examined. Suggestions are made for future work. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Amer Museum Nat Hist, Dept Astrophys, New York, NY 10024 USA. RP Breckinridge, JB (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM jbreckin@jpl.nasa.gov; bro@amnh.org NR 29 TC 28 Z9 28 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 JAN 10 PY 2004 VL 600 IS 2 BP 1091 EP 1098 DI 10.1086/379872 PN 1 PG 8 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 769NT UT WOS:000188657200051 ER PT J AU Conselice, CJ Grogin, NA Jogee, S Lucas, RA Dahlen, T de Mello, D Gardner, JP Mobasher, B Ravindranath, S AF Conselice, CJ Grogin, NA Jogee, S Lucas, RA Dahlen, T de Mello, D Gardner, JP Mobasher, B Ravindranath, S TI Observing the formation of the Hubble sequence in the Great Observatories Origins Deep Survey SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : elliptical and lenticular, cD; galaxies : evolution; galaxies : formation; galaxies : spiral ID HIGH-REDSHIFT GALAXIES; STAR-FORMING GALAXIES; PHYSICAL MORPHOLOGY; STARBURST GALAXIES; NEARBY; ULTRAVIOLET AB Understanding the physical formation of the Hubble sequence remains one of the most important unsolved astrophysical problems. Searches for protodisks and proto-elliptical galaxies can now be effectively done using deep wide-field Hubble Space Telescope images taken with the new Advanced Camera for Surveys. Through an analysis of the concentrations (C), asymmetries (A), and clumpiness values (S) of galaxies found in the Great Observatories Origins Deep Survey Field South, we are able to identify objects possibly forming onto the Hubble sequence. Using this approach, we detect a sizeable population of star-forming luminous diffuse objects and star-forming luminous asymmetric objects between redshifts 0.52 and z<1. The luminous asymmetric objects are found at a similar abundance, with a peak at z&SIM;1. We argue that these galaxies are a subset of modern disks and elliptical galaxies in formation. The comoving volume density of the luminous diffuse objects between z=1 and 2 is similar to the local density of bright disk galaxies, with values &SIM;5x10(5) Gpc(-3). The spectral energy distributions of these objects are mostly consistent with starbursts, or star-forming normal galaxies, with average uncorrected for extinction star formation rates of &SIM;4 M-&ODOT; yr(-1). These galaxies also host 35%-40% of the star formation activity at 18 Gyr. These parameters are measured at rest-frame UV wavelengths (1200 Angstrom < λ < 2000 Angstrom) on images with a rest frame resolution of less than 0.8 kpc. Galaxy radii are found to scale with redshift approximately as the Hubble parameter H-1(z). This is in accord with the theoretical expectation that the typical sizes of the luminous parts of galaxies should track the expected evolution in the virial radius of dark matter halos. The mean ratio of the semimajor axis to the semiminor axis for a bright well-resolved sample of galaxies at zsimilar to4 is b/a=0.65 suggesting that these Lyman break galaxies are not drawn from a spheroidal population. However, the median concentration index of this sample is C=3.5, which is closer to the typical concentration indices of nearby elliptical galaxies (Csimilar to4) than to the values for local disk galaxies of type Sb and later (C<2). C1 Space Telescope Sci Inst, Baltimore, MD 21218 USA. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. Univ Melbourne, Sch Phys, Parkville, Vic 3010, Australia. CALTECH, Palomar Observ, Pasadena, CA 91125 USA. NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. Univ Calif Santa Cruz, Dept Astron & Astrophys, Santa Cruz, CA 95064 USA. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Ferguson, HC (reprint author), Space Telescope Sci Inst, 3700 San Martin Dr, Baltimore, MD 21218 USA. RI Conselice, Christopher/B-4348-2013; OI Moustakas, Leonidas/0000-0003-3030-2360 NR 29 TC 215 Z9 217 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 JAN 10 PY 2004 VL 600 IS 2 BP L107 EP L110 DI 10.1086/378578 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 769NV UT WOS:000188657400004 ER PT J AU Giavalisco, M Dickinson, M Ferguson, HC Ravindranath, S Kretchmer, C Moustakas, LA Madau, P Fall, SM Gardner, JP Livio, M Papovich, C Renzini, A Spinrad, H Stern, D Riess, A AF Giavalisco, M Dickinson, M Ferguson, HC Ravindranath, S Kretchmer, C Moustakas, LA Madau, P Fall, SM Gardner, JP Livio, M Papovich, C Renzini, A Spinrad, H Stern, D Riess, A TI The rest-frame ultraviolet luminosity density of star-forming galaxies at redshifts z > 3.5 SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmology : observations; galaxies : distances and redshifts; galaxies : evolution; galaxies : formation ID LYMAN-BREAK GALAXIES; HUBBLE DEEP FIELD; FORMATION HISTORY; RADIATIVE-TRANSFER; CLUMPY UNIVERSE; REIONIZATION; EVOLUTION; DUST; Z-SIMILAR-TO-6; INTENSITY AB We have measured the rest-frame lambdasimilar to1500 Angstrom comoving specific luminosity density of star-forming galaxies at redshift 3.525%) than late-type spirals and optically selected starbursts. These results are consistent with the scenario that early-epoch (z>>1) gas-rich dissipative processes (e.g., major mergers) have played an important role in developing large central concentrations in early-type E/Sa galaxies and that a concurrent growth of central black holes and bulges occurs in some of these early merger events. The lower AGN fraction and concentration indices in the majority of the optically selected starbursts at zless than or similar to1 suggest that either the starbursts and early types are different in nature (being, respectively, disk and bulge dominated) and/or they are in different evolutionary phases, such that some of the starbursts in major mergers evolve into early types as the dynamical phase of the merger evolves and the spectral signature of the starburst fades out. The starbursts have, on average, larger asymmetries than our control sample of normal galaxies in both rest-frame B and R bands, suggesting that a significant fraction of the starburst activity is tidally triggered. C1 Space Telescope Sci Inst, Baltimore, MD 21218 USA. European Space Agcy, Dept Space Sci, F-75738 Paris 15, France. NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. CALTECH, Pasadena, CA 91125 USA. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. RP Mobasher, B (reprint author), Space Telescope Sci Inst, 3700 San Martin Dr, Baltimore, MD 21218 USA. EM b.mobasher@stsci.edu RI Conselice, Christopher/B-4348-2013 NR 26 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 JAN 10 PY 2004 VL 600 IS 2 BP L143 EP L146 DI 10.1086/378180 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 769NV UT WOS:000188657400013 ER PT J AU Moustakas, LA Casertano, S Conselice, CJ Dickinson, ME Eisenhardt, P Ferguson, HC Giavalisco, M Grogin, NA Koekemoer, AM Lucas, RA Mobasher, B Papovich, C Renzini, A Somerville, RS Stern, D AF Moustakas, LA Casertano, S Conselice, CJ Dickinson, ME Eisenhardt, P Ferguson, HC Giavalisco, M Grogin, NA Koekemoer, AM Lucas, RA Mobasher, B Papovich, C Renzini, A Somerville, RS Stern, D TI Morphologies and spectral energy distributions of extremely red galaxies in the GOODS-South field SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : evolution; galaxies : fundamental parameters; galaxies : high-redshift; galaxies : stellar content; infrared : galaxies ID STAR-FORMING GALAXIES; K20 SURVEY; OBJECTS; REDSHIFT; OLD; COUNTERPARTS; POPULATION; SAMPLE; MODELS AB Using U'-through K-s-band imaging data in the Great Observatories Origins Deep Survey-South (GOODS-South) field, we construct a large, complete sample of 275 extremely red objects (EROs; K-s<22.0, R-K-s>3.35; AB), all with deep Hubble Space Telescope Advanced Camera for Surveys imaging in B-435, V-606, i(775), and z(850) and well-calibrated photometric redshifts. Quantitative concentration and asymmetry measurements fail to separate EROs into distinct morphological classes. We therefore visually classify the morphologies of all EROs into four broad types-"early" (elliptical-like), "late" (disk galaxies), "irregular," and "other" (chain galaxies and low surface brightness galaxies)-and calculate their relative fractions and comoving space densities. For a broad range of limiting magnitudes and color thresholds, the relative number of early-type EROs is approximately constant at 33%-44%, and the comoving space densities of early- and late-type EROs are comparable. Mean rest-frame spectral energy distributions (SEDs) at λ(rest)&AP;0.1-1.2 μm are constructed for all EROs. The SEDs are extremely similar in their range of shapes, independent of morphological type. The implication is that any differences between the broadband SEDs of early-type EROs and the other types are relatively subtle, and there is no robust way of photometrically distinguishing between different morphological types with usual optical/near-infrared photometry. C1 Space Telescope Sci Inst, Baltimore, MD 21218 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. European Space Agcy, Dept Space Sci, F-75738 Paris 15, France. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. European So Observ, D-85748 Garching, Germany. RP Moustakas, LA (reprint author), Space Telescope Sci Inst, 3700 San Martin Dr, Baltimore, MD 21218 USA. RI Conselice, Christopher/B-4348-2013; OI Moustakas, Leonidas/0000-0003-3030-2360; Koekemoer, Anton/0000-0002-6610-2048 NR 32 TC 59 Z9 61 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 JAN 10 PY 2004 VL 600 IS 2 BP L131 EP L134 DI 10.1086/380428 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 769NV UT WOS:000188657400010 ER PT J AU Papovich, C Dickinson, M Ferguson, HC Giavalisco, M Lotz, J Madau, P Idzi, R Kretchmer, C Moustakas, LA de Mello, DF Gardner, JP Rieke, MJ Somerville, RS Stern, D AF Papovich, C Dickinson, M Ferguson, HC Giavalisco, M Lotz, J Madau, P Idzi, R Kretchmer, C Moustakas, LA de Mello, DF Gardner, JP Rieke, MJ Somerville, RS Stern, D TI Evolution in the colors of Lyman break galaxies from z similar to 4 to z similar to 3 SO ASTROPHYSICAL JOURNAL LA English DT Article DE cosmology : observations; early universe; galaxies : evolution; galaxies : formation; galaxies : high-redshift; galaxies : photometry ID HUBBLE DEEP FIELD; PHOTOMETRIC REDSHIFTS; STAR-FORMATION; ULTRAVIOLET; SPECTRA; DENSITY; CATALOG AB The integrated colors of distant galaxies provide a means for interpreting the properties of their stellar content. Here we use rest-frame UV-to-optical colors to constrain the spectral energy distributions and stellar populations of color-selected, B-dropout galaxies at zsimilar to4 in the Great Observatories Origins Deep Survey (GOODS). We combine the Advanced Camera for Surveys data with ground-based near-infrared images, which extend the coverage of galaxies at zsimilar to4 to the rest-frame B band. We observe a color-magnitude trend in the rest-frame m(UV)-B versus B diagram for the zsimilar to4 galaxies that has a fairly well-defined "blue envelope," and is strikingly similar to that of color-selected, U-dropout galaxies at zsimilar to3. We also find that although the co-moving luminosity density at rest-frame UV wavelengths (1600 Angstrom) is roughly comparable at zsimilar to3 and similar to4, the luminosity density at rest-frame optical wavelengths increases by about one-third from zsimilar to4 to similar to3. Although the star formation histories of individual galaxies may involve complex and stochastic events, the evolution in the global luminosity density of the UV-bright galaxy population corresponds to an average star formation history with a star formation rate that is constant or increasing over these redshifts. This suggests that the evolution in the luminosity density corresponds to an increase in the stellar mass density of greater than or similar to33%. C1 Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. Space Telescope Sci Inst, Baltimore, MD 21218 USA. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. Univ Calif Santa Cruz, Dept Phys, Santa Cruz, CA 95064 USA. Univ Calif Santa Cruz, Dept Astron & Astrophys, Santa Cruz, CA 95064 USA. NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Papovich, C (reprint author), Univ Arizona, Steward Observ, 933 N Cherry Ave, Tucson, AZ 85721 USA. EM papovich@as.arizona.edu; med@stsci.edu; ferguson@stsci.edu; mauro@stsci.edu; jlotz@scipp.ucsc.edu; pmadau@ucolick.org; idzi@stsci.edu; claudiak@stsci.edu; leonidas@stsci.edu; duilia@ipanema.gsfc.nasa.gov; gardner@harmony.gsfc.nasa.gov; mrieke@as.arizona.edu; somerville@stsci.edu; stern@zwolfkinder.jpl.nasa.gov OI Moustakas, Leonidas/0000-0003-3030-2360 NR 19 TC 31 Z9 31 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 JAN 10 PY 2004 VL 600 IS 2 BP L111 EP L114 DI 10.1086/381075 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 769NV UT WOS:000188657400005 ER PT J AU Somerville, RS Moustakas, LA Mobasher, B Gardner, JP Cimatti, A Conselice, C Daddi, E Dahlen, T Dickinson, M Eisenhardt, P Lotz, J Papovich, C Renzini, A Stern, D AF Somerville, RS Moustakas, LA Mobasher, B Gardner, JP Cimatti, A Conselice, C Daddi, E Dahlen, T Dickinson, M Eisenhardt, P Lotz, J Papovich, C Renzini, A Stern, D TI The redshift distribution of near-infrared-selected galaxies in the Great Observatories Origins Deep Survey as a test of galaxy formation scenarios SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : evolution; galaxies : formation ID PHOTOMETRIC REDSHIFTS; LUMINOSITY FUNCTION; K20 SURVEY; EVOLUTION; SAMPLE; MODELS AB The redshift distribution of near-IR-selected galaxies is often used to attempt to discriminate between the classical view of galaxy formation, in which present-day luminous galaxies were assembled at early times and evolve through the passive aging of their stellar populations, and that of hierarchical structure formation, in which galaxies were assembled more recently via the merging of smaller objects. We carry out such a test here by computing the distribution of photometric redshifts of K-AB<22 galaxies in the Great Observatories Origins Deep Field Survey (GOODS) southern field, and comparing the results with predictions from a semianalytic model based on hierarchical structure formation, and a classical "passive evolution" model. We find that the redshift distributions at z&LSIM;1.5 of both the hierarchical and passive models are very similar to the observed one. At z&GSIM;1.5 the hierarchical model shows a deficit of galaxies, while the passive model predicts an excess. We investigate the nature of the observed galaxies in the redshift range where the models diverge, and find that the majority have highly disturbed morphologies, suggesting that they may be merger-induced starbursts. While the hierarchical model used here does not produce these objects in great enough numbers, the appearance of this population is clearly in better qualitative agreement with the hierarchical picture than with the classical passive evolution scenario. We conclude that the observations support the general framework of hierarchical formation, but suggest the need for new or modified physics in the models. C1 Space Telescope Sci Inst, Baltimore, MD 21218 USA. NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. Osserv Astrofis Arcetri, I-50125 Florence, Italy. CALTECH, Pasadena, CA 91125 USA. European So Observ, D-85748 Garching, Germany. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Calif Santa Cruz, Dept Astron, Santa Cruz, CA 95064 USA. Univ Arizona, Steward Observ, Tucson, AZ 85721 USA. RP Somerville, RS (reprint author), Space Telescope Sci Inst, 3700 San Martin Dr, Baltimore, MD 21218 USA. EM somerville@stsci.edu; leonidas@stsci.edu; mobasher@stsci.edu; jonathan.p.gardner@nasa.gov; cimatti@arcetri.astro.it; cc@astro.caltech.edu; edaddi@eso.org; dahlen@stsci.edu; med@stsci.edu; prme@kromos.jpl.nasa.gov; lotz@stsci.edu; papovich@as.arizona.edu; arenzini@eso.org; stern@zwolfkinder.jpl.nasa.gov RI Daddi, Emanuele/D-1649-2012; Conselice, Christopher/B-4348-2013; OI Daddi, Emanuele/0000-0002-3331-9590; Moustakas, Leonidas/0000-0003-3030-2360 NR 24 TC 77 Z9 77 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 JAN 10 PY 2004 VL 600 IS 2 BP L135 EP L138 DI 10.1086/378665 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 769NV UT WOS:000188657400011 ER PT J AU Somerville, RS Lee, K Ferguson, HC Gardner, JP Moustakas, LA Giavalisco, M AF Somerville, RS Lee, K Ferguson, HC Gardner, JP Moustakas, LA Giavalisco, M TI Cosmic variance in the Great Observatories Origins Deep Survey SO ASTROPHYSICAL JOURNAL LA English DT Article DE galaxies : statistics; large-scale structure of universe ID STATISTICS; GALAXIES; FIELD AB Cosmic variance is the uncertainty in observational estimates of the volume density of extragalactic objects such as galaxies or quasars arising from the underlying large-scale density fluctuations. This is often a significant source of uncertainty, especially in deep galaxy surveys, which tend to cover relatively small areas. We present estimates of the relative cosmic variance for one-point statistics (i.e., number densities) for typical scales and volumes sampled by the Great Observatories Origins Deep Survey (GOODS). We use two approaches: (1) For objects with a known two-point correlation function that is well approximated by a power law, one can use the standard analytic formalism to calculate the cosmic variance (in excess of shot noise). We use this approach to estimate the cosmic variance for several populations that are being studied in the GOODS program (extremely red objects [EROs] at zsimilar to1 and Lyman break galaxies [LBGs] at zsimilar to3 and zsimilar to4) using clustering information for similar populations in the literature. (2) For populations with unknown clustering, one can use predictions from cold dark matter theory to obtain a rough estimate of the variance as a function of number density. We present a convenient plot that allows one to use this approach to read off the cosmic variance for a population with a known mean redshift and estimated number density. We conclude that for the volumes sampled by GOODS, cosmic variance is a significant source of uncertainty for strongly clustered objects (similar to40%-60% for EROs) and less serious for less clustered objects (similar to10%-20% for LBGs). C1 Space Telescope Sci Inst, Baltimore, MD 21218 USA. Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA. NASA, Goddard Space Flight Ctr, Astron & Solar Phys Lab, Greenbelt, MD 20771 USA. RP Somerville, RS (reprint author), Space Telescope Sci Inst, 3700 San Martin Dr, Baltimore, MD 21218 USA. EM somerville@stsci.edu; soolee@stsci.edu; ferguson@stsci.edu; jonathan.p.gardner@nasa.gov; leonidas@stsci.edu; mauro@stsci.edu OI Moustakas, Leonidas/0000-0003-3030-2360 NR 14 TC 182 Z9 184 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 JAN 10 PY 2004 VL 600 IS 2 BP L171 EP L174 DI 10.1086/378628 PN 2 PG 4 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 769NV UT WOS:000188657400020 ER PT J AU Howard, AD Moore, JM AF Howard, AD Moore, JM TI Scarp-bounded benches in Gorgonum Chaos, Mars: Formed beneath an ice-covered lake? SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID CLASSIFICATION AB Level, bench-like platforms edged with scarps facing the interior of the Martian Gorgonum Chaos basin may have formed in conjunction with an ancient ice-covered lake. These benches, however, lack the typical features of shorelines associated with wave and current transport and erosion, such as crescentic embayments, spits, barrier islands, and wave-cut cliffs. Rather, the basin-facing platform edges are commonly rounded and cumulate in planform, often evenly encircling buttes protruding above the level of the benches. The benches are postulated to have been formed by outward growth in a quiescent environment, possibly by deformative lateral flow of sediment below the ice-water interface in a perennially frozen lake due to the weight of the ice overburden. C1 Univ Virginia, Dept Environm Sci, Charlottesville, VA 22904 USA. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Howard, AD (reprint author), Univ Virginia, Dept Environm Sci, POB 400123, Charlottesville, VA 22904 USA. EM ah6p@virginia.edu; jeff.moore@nasa.gov NR 16 TC 14 Z9 14 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 JAN 10 PY 2004 VL 31 IS 1 AR L01702 DI 10.1029/2003GL018925 PG 5 WC Geosciences, Multidisciplinary SC Geology GA 765MD UT WOS:000188286600001 ER PT J AU Maynard, AD Baron, PA Foley, M Shvedova, AA Kisin, ER Castranova, V AF Maynard, AD Baron, PA Foley, M Shvedova, AA Kisin, ER Castranova, V TI Exposure to carbon nanotube material: Aerosol release during the handling of unrefined single-walled carbon nanotube material SO JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH-PART A LA English DT Article AB Carbon nanotubes represent a relatively recently discovered allotrope of carbon that exhibits unique properties. While commercial interest in the material is leading to the development of mass production and handling facilities, little is known of the risk associated with exposure. In a two-part study, preliminary investigations have been carried out into the potential exposure routes and toxicity of single-walled carbon nanotube material (SWCNT)-a specific form of the allotrope. The material is characterized by bundles of fibrous carbon molecules that may be a few nanometers; in diameter, but micrometers in length. The two production processes investigated use-transition metal catalysts, leading to the inclusion of nanometer-scale metallic particles within unrefined SWCNT material. A laboratory-based study was undertaken to evaluate the physical nature of the aerosol formed from SWCNT during mechanical agitation. This was complemented by a Field study in which airborne and dermal exposure to SWCNT was investigated while handling unrefined material. Although laboratory studies indicated that with sufficient agitation, unrefined SWCNT material can release fine particles into the air, concentrations generated while handling material in the field were very low. Estimates of the airborne concentration of nanotube material generated during handling suggest that concentrations were lower than 53 mug/m(3) in all cases. Clove deposits of SWCNT during handling were estimated at between 0.2 mg and 6 mg per band. C1 NIOSH, Cincinnati, OH 45226 USA. NASA, Lyndon B Johnson Space Ctr, Comprehens Hlth Serv Inc, Houston, TX 77058 USA. NIOSH, Pathol & Physiol Res Branch, HELD, Morgantown, WV USA. W Virginia Univ, Dept Physiol & Pharmacol, Morgantown, WV 26506 USA. RP Maynard, AD (reprint author), NIOSH, 4676 Columbia Pkwy, Cincinnati, OH 45226 USA. EM amaynard@cdc.gov RI Maynard, Andrew/D-1076-2010; OI Maynard, Andrew/0000-0003-2117-5128 NR 7 TC 485 Z9 502 U1 5 U2 63 PU TAYLOR & FRANCIS INC PI PHILADELPHIA PA 325 CHESTNUT ST, SUITE 800, PHILADELPHIA, PA 19106 USA SN 1528-7394 J9 J TOXICOL ENV HEAL A JI J. TOXICOL. ENV. HEALTH PT A PD JAN 9 PY 2004 VL 67 IS 1 BP 87 EP 107 DI 10.1080/15287390490253688 PG 21 WC Environmental Sciences; Public, Environmental & Occupational Health; Toxicology SC Environmental Sciences & Ecology; Public, Environmental & Occupational Health; Toxicology GA 763HJ UT WOS:000188078700006 PM 14668113 ER PT J AU Beacom, JF Bell, NF Hooper, D Learned, JG Pakvasa, S Weiler, TJ AF Beacom, JF Bell, NF Hooper, D Learned, JG Pakvasa, S Weiler, TJ TI Pseudo-Dirac neutrinos: A challenge for neutrino telescopes SO PHYSICAL REVIEW LETTERS LA English DT Article ID FLAVOR OSCILLATIONS; COSMOLOGY; SCALES; MODELS; MASSES AB Neutrinos may be pseudo-Dirac states, such that each generation is actually composed of two maximally mixed Majorana neutrinos separated by a tiny mass difference. The usual active neutrino oscillation phenomenology would be unaltered if the pseudo-Dirac splittings are deltam(2)less than or similar to10(-12) eV(2); in addition, neutrinoless double beta decay would be highly suppressed. However, it may be possible to distinguish pseudo-Dirac from Dirac neutrinos using high-energy astrophysical neutrinos. By measuring flavor ratios as a function of L/E, mass-squared differences down to deltam(2)similar to10(-18) eV(2) can be reached. We comment on the possibility of probing cosmological parameters with neutrinos. C1 Fermilab Natl Accelerator Lab, NASA, Fermilab Astrophys Ctr, Batavia, IL 60510 USA. Univ Calif Santa Barbara, Kavli Inst Theoret Phys, Santa Barbara, CA 93106 USA. Univ Wisconsin, Dept Phys, Madison, WI 53706 USA. Univ Hawaii, Dept Phys & Astron, Honolulu, HI 96822 USA. Vanderbilt Univ, Dept Phys & Astron, Nashville, TN 37235 USA. RP Beacom, JF (reprint author), Fermilab Natl Accelerator Lab, NASA, Fermilab Astrophys Ctr, POB 500, Batavia, IL 60510 USA. OI Beacom, John/0000-0002-0005-2631 NR 40 TC 78 Z9 78 U1 0 U2 0 PU AMERICAN PHYSICAL SOC PI COLLEGE PK PA ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA SN 0031-9007 J9 PHYS REV LETT JI Phys. Rev. Lett. PD JAN 9 PY 2004 VL 92 IS 1 AR 011101 DI 10.1103/PhysRevLett.92.011101 PG 4 WC Physics, Multidisciplinary SC Physics GA 762JM UT WOS:000187968500003 PM 14753977 ER PT J AU Ksendzov, A Homer, ML Manfreda, AM AF Ksendzov, A Homer, ML Manfreda, AM TI Integrated optics ring-resonator chemical sensor with polymer transduction layer SO ELECTRONICS LETTERS LA English DT Article ID MICROCAVITY AB An integrated optics chemical sensor based on a ring resonator with an ethyl cellulose polymer coating has been demonstrated. The measured sensitivity to isopropanol in air is 50 ppm-the level immediately useful for health-related air quality monitoring. The resonator was fabricated using SiO2 and SixNy materials. The signal readout is based on tracking the wavelength of a resonance peak. The resonator layout optimisation for sensing applications is discussed. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Ksendzov, A (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM alexander.ksendzov@jpl.nasa.gov NR 7 TC 37 Z9 40 U1 0 U2 4 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 JAN 8 PY 2004 VL 40 IS 1 BP 63 EP 65 DI 10.1049/el:20040062 PG 3 WC Engineering, Electrical & Electronic SC Engineering GA 764BY UT WOS:000188172300041 ER PT J AU Arellano, AF Kasibhatla, PS Giglio, L van der Werf, GR Randerson, JT AF Arellano, AF Kasibhatla, PS Giglio, L van der Werf, GR Randerson, JT TI Top-down estimates of global CO sources using MOPITT measurements SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID CARBON-MONOXIDE; TROPOSPHERIC CHEMISTRY; EMISSIONS; ASIA; MODEL AB We present a synthesis inversion of CO emissions from various geographical regions and for various source categories for the year 2000 using CO retrievals from the MOPITT (Measurements of Pollution in the Troposphere) instrument. We find a large discrepancy between our top-down estimates and recent bottom-up estimates of CO emissions from fossil fuel/biofuel (FFBF) use in Asia. A key conclusion of this study is that CO emissions in East Asia (EAS) are about a factor of 1.8-2 higher than recent bottom-up estimates. C1 Duke Univ, Nicholas Sch Environm & Earth Sci, Durham, NC 27708 USA. NASA, GSFC, SSAI, Greenbelt, MD USA. USDA, FAS, NASA, GSFC, Greenbelt, MD USA. CALTECH, Div Geol & Planetary Sci, Pasadena, CA 91125 USA. CALTECH, Div Engn & Appl Sci, Pasadena, CA 91125 USA. RP Arellano, AF (reprint author), Duke Univ, Nicholas Sch Environm & Earth Sci, Box 90328, Durham, NC 27708 USA. EM afa3@duke.edu RI Arellano, Avelino, Jr./F-5674-2010; Kasibhatla, Prasad/A-2574-2010; van der Werf, Guido/M-8260-2016 OI van der Werf, Guido/0000-0001-9042-8630 NR 17 TC 109 Z9 111 U1 0 U2 5 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JAN 8 PY 2004 VL 31 IS 1 AR L01104 DI 10.1029/2003GL018609 PG 5 WC Geosciences, Multidisciplinary SC Geology GA 765MB UT WOS:000188286400002 ER PT J AU Irie, H Kondo, Y Koike, M Takegawa, N Tabazadeh, A Reeves, JM Sachse, GW Vay, SA Anderson, BE Mahoney, MJ AF Irie, H Kondo, Y Koike, M Takegawa, N Tabazadeh, A Reeves, JM Sachse, GW Vay, SA Anderson, BE Mahoney, MJ TI Liquid ternary aerosols of HNO3/H2SO4/H2O in the Arctic tropopause region SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID REACTIVE NITROGEN; UPPER TROPOSPHERE; CLOUD PARTICLES; STRATOSPHERE; NUCLEATION; SIZE; WINTER AB Measurements of total reactive nitrogen (NOy) concentrations in the gas and aerosol phases were made on board the NASA DC-8 aircraft within 1 km above the Arctic tropopause in February 2000. As temperatures decreased, NOy was taken up into the background sulfate aerosols. The observed temperature-dependent NOy uptake agrees well with that calculated from a model of nitric acid (HNO3) uptake to form liquid HNO3/H2O/H2SO4 ternary droplets. The observations reported here provide the first direct evidence for the formation of ternary droplets in the Arctic tropopause region. C1 Natl Inst Environm Studies, Satellite Remote Sensing Res Team, Tsukuba, Ibaraki 3058506, Japan. Univ Tokyo, Adv Sci & Technol Res Ctr, Meguro Ku, Tokyo 1538904, Japan. Univ Tokyo, Grad Sch Sci, Dept Earth & Planetary Sci, Tokyo 1130033, Japan. NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. Univ Denver, Dept Engn, Denver, CO 80208 USA. NASA, Langley Res Ctr, Hampton, VA 23681 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Irie, H (reprint author), Natl Inst Environm Studies, Satellite Remote Sensing Res Team, 16-2 Onogawa, Tsukuba, Ibaraki 3058506, Japan. EM irie.hitoshi@nies.go.jp RI Koike, Makoto/F-4366-2011; Kondo, Yutaka/D-1459-2012 NR 20 TC 5 Z9 5 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JAN 8 PY 2004 VL 31 IS 1 AR L01105 DI 10.1029/2003GL018678 PG 5 WC Geosciences, Multidisciplinary SC Geology GA 765MB UT WOS:000188286400003 ER PT J AU Christensen, LE Okumura, M Sander, SP Friedl, RR Miller, CE Sloan, JJ AF Christensen, LE Okumura, M Sander, SP Friedl, RR Miller, CE Sloan, JJ TI Measurements of the rate constant of HO2+NO2+N-2-HO2NO2+N-2 using near-infrared wavelength-modulation spectroscopy and UV-visible absorption spectroscopy SO JOURNAL OF PHYSICAL CHEMISTRY A LA English DT Article ID SELF-REACTION; TEMPERATURE-DEPENDENCE; HIGH-RESOLUTION; GAS-PHASE; HO2; KINETICS; NO2; BAND; STRATOSPHERE; EXISTENCE AB Rate coefficients for the reaction HO2 + NO2 + N-2 --> HO2NO2 + N2 (reaction 1) were measured using simultaneous near-IR and UV spectroscopy from 220 to 298 K and from 45 to 200 Toff. Using the data acquired in the present experiment, the low-pressure and high-pressure limit rate constants for reaction I were determined to be k(o) = (2.1 +/- 0.1) x 10(-31) x (T/3000)(-(3.1+/-10.1)) cm(6) molecule(-2) s(-1) and K-infinity = (2.4 +/- 0.1) x 10(-12) x (T/300))(-(1.9+/-0.5)) cm(3) molecule(-1) s(-1), using the expressions for rate constants adopted by the NASA data evaluation panel (F-c = 0.6). The reaction rate was significantly enhanced in the presence of methanol due to a chaperone effect involving an HO2CH3OH complex. Enhancement parameters for this process were quantified as a function of temperature. During the course of our studies, we observed an unexpected time-dependent UV absorption unaccounted for in previous examinations of reaction I that employed UV spectroscopy to monitor HO2. We show that this absorption, which may have led to errors in those prior studies, is due to the process NO2 + NO2 reversible arrow N2O4 (reaction 3). Using UV-visible spectroscopy, we determine k(-3) to be (36 +/- 10) s(-1) at 231 K and 100 Torr using the NASA-recommended equilibrium constant for the dimerization of NO2. This represents the first measurement of k(-3) at T < 250 K. C1 CALTECH, Arthur Amos Noyes Lab Chem Phys, Div Chem & Chem Phys, Pasadena, CA 91125 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Waterloo, Dept Chem, Waterloo, ON N2L 3G1, Canada. RP Christensen, LE (reprint author), CALTECH, Arthur Amos Noyes Lab Chem Phys, Div Chem & Chem Phys, Pasadena, CA 91125 USA. EM lance.christensen@jpl.nasa.gov; mo@its.caltech.edu; stanley.sander@jpl.nasa.gov RI Okumura, Mitchio/I-3326-2013 OI Okumura, Mitchio/0000-0001-6874-1137 NR 39 TC 20 Z9 20 U1 2 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 JAN 8 PY 2004 VL 108 IS 1 BP 80 EP 91 DI 10.1021/jp035905o PG 12 WC Chemistry, Physical; Physics, Atomic, Molecular & Chemical SC Chemistry; Physics GA 760MU UT WOS:000187838500013 ER PT J AU Flasar, FM Kunde, VG Achterberg, RK Conrath, BJ Simon-Miller, AA Nixon, CA Gierasch, PJ Romani, PN Bezard, B Irwin, P Bjoraker, GL Brasunas, JC Jennings, DE Pearl, JC Smith, MD Orton, GS Spilker, LJ Carlson, R Calcutt, SB Read, PL Taylor, FW Parrish, P Barucci, A Courtin, R Coustenis, A Gautier, D Lellouch, E Marten, A Prange, R Biraud, Y Fouchet, T Ferrari, C Owen, TC Abbas, MM Samuelson, RE Raulin, F Ade, P Cesarsky, CJ Grossman, KU Coradini, A AF Flasar, FM Kunde, VG Achterberg, RK Conrath, BJ Simon-Miller, AA Nixon, CA Gierasch, PJ Romani, PN Bezard, B Irwin, P Bjoraker, GL Brasunas, JC Jennings, DE Pearl, JC Smith, MD Orton, GS Spilker, LJ Carlson, R Calcutt, SB Read, PL Taylor, FW Parrish, P Barucci, A Courtin, R Coustenis, A Gautier, D Lellouch, E Marten, A Prange, R Biraud, Y Fouchet, T Ferrari, C Owen, TC Abbas, MM Samuelson, RE Raulin, F Ade, P Cesarsky, CJ Grossman, KU Coradini, A TI An intense stratospheric jet on Jupiter SO NATURE LA English DT Article ID UPPER TROPOSPHERE; SPATIAL-ORGANIZATION; TIME-DEPENDENCE; THERMAL WAVES; OSCILLATION; SATELLITES; TEMPERATURES; PLANETS AB The Earth's equatorial stratosphere shows oscillations in which the east - west winds reverse direction and the temperatures change cyclically with a period of about two years(1,2). This phenomenon, called the quasi-biennial oscillation, also affects the dynamics of the mid- and high-latitude stratosphere and weather in the lower atmosphere(2). Ground-based observations have suggested(3-5) that similar temperature oscillations (with a 4-5-yr cycle) occur on Jupiter, but these data suffer from poor vertical resolution and Jupiter's stratospheric wind velocities have not yet been determined. Here we report maps of temperatures and winds with high spatial resolution, obtained from spacecraft measurements of infrared spectra of Jupiter's stratosphere. We find an intense, high-altitude equatorial jet with a speed of similar to140 m s(-1), whose spatial structure resembles that of a quasi-quadrennial oscillation. Wave activity in the stratosphere also appears analogous to that occurring on Earth. A strong interaction between Jupiter and its plasma environment produces hot spots in its upper atmosphere and stratosphere near its poles(6-9), and the temperature maps define the penetration of the hot spots into the stratosphere. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Univ Maryland, Dept Astron, College Pk, MD 20742 USA. Sci Syst & Applicat Inc, Lanham, MD 20706 USA. Cornell Univ, Dept Astron, Ithaca, NY 14853 USA. Observ Paris, LESIA, CNRS, FRE 2461, F-91925 Meudon, France. Univ Oxford, Clarendon Lab, Oxford OX1 3PU, England. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. CEA Saclay, Serv Astrophys, F-91191 Gif Sur Yvette, France. Univ Hawaii, Inst Astron, Honolulu, HI 96822 USA. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. Univ Paris 7 & 12, LISA, CNRS, UMR 7583, F-94010 Creteil, France. Univ Cardiff, Dept Phys & Astron, Cardiff CF24 3YB, S Glam, Wales. European So Observ, D-85748 Garching, Germany. Gesamthsch Wuppertal, Dept Phys, D-5600 Wuppertal 1, Germany. CNR, Inst Astrofis Spaziale, Area Recerca Tor Vergata, I-00133 Rome, Italy. RP Flasar, FM (reprint author), NASA, Goddard Space Flight Ctr, Code 693, Greenbelt, MD 20771 USA. EM f.m.flasar@nasa.gov RI Nixon, Conor/A-8531-2009; Flasar, F Michael/C-8509-2012; Smith, Michael/C-8875-2012; Romani, Paul/D-2729-2012; Bjoraker, Gordon/D-5032-2012; Jennings, Donald/D-7978-2012; brasunas, john/I-2798-2013; Simon, Amy/C-8020-2012; Ferrari, Cecile/P-9735-2016; Fouchet, Thierry/C-6374-2017; OI Nixon, Conor/0000-0001-9540-9121; Simon, Amy/0000-0003-4641-6186; Ferrari, Cecile/0000-0001-5962-7439; Fouchet, Thierry/0000-0001-9040-8285; Calcutt, Simon/0000-0002-0102-3170; Irwin, Patrick/0000-0002-6772-384X NR 28 TC 59 Z9 60 U1 0 U2 3 PU NATURE PUBLISHING GROUP PI LONDON PA MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND SN 0028-0836 J9 NATURE JI Nature PD JAN 8 PY 2004 VL 427 IS 6970 BP 132 EP 135 DI 10.1038/nature02142 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 760YY UT WOS:000187863900029 PM 14712270 ER PT J AU Kwok, R Cunningham, GF Pang, SS AF Kwok, R Cunningham, GF Pang, SS TI Fram Strait sea ice outflow SO JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS LA English DT Article DE Fram Strait; ice export; ice thickness ID NORTH-ATLANTIC OSCILLATION; COLD HALOCLINE LAYER; ARCTIC-OCEAN; CIRCULATION; MOTION; EXPORT; LINK; SAR AB We summarize 24 years (1978-2002) of ice export estimates and examine, over a 9-year record, the associated variability in the time-varying upward-looking sonar (ULS) thickness distributions of the Fram Strait. A more thorough assessment of the PMW (passive microwave) ice motion with 5 years of synthetic aperture radar (SAR) observations shows the uncertainties to be consistent with that found by Kwok and Rothrock [1999], giving greater confidence to the record of ice flux calculations. Interesting details of the cross-strait motion profiles and ice cover characteristics revealed by high-resolution SAR imagery are discussed. The average annual ice area flux over the period is 866,000 km(2)/yr. Between the 1980s and 1990s, the decadal difference in the net exported ice area is similar to400,000 km(2), approximately half the annual average. Except for the years with extreme negative NAO, correlation of winter ice area export with the NAO index remains high (R-2 = 0.62). With thickness estimates from ULS moorings, we estimate the average annual ice volume flux (8 years) to be similar to2218 km(3)/yr (similar to0.07 Sv). Over the similar to9-year ULS ice thickness data set, there is an overall decrease of 0.45 m in the mean ice thickness over the entire time series and a decrease of 0.23 m over the winter months (December through March). Correspondingly, the mode of the MY ice thickness exhibits an overall decrease of 0.55 m and a winter decrease of 0.42 m. These are significant trends. Whether these trends are indicative of the thickness trends of the Arctic Ocean is examined, as the time-varying behavior of the monthly ULS thickness distributions can be related not only to the seasonal cycle in the basal growth and melt, but also to the magnitude and pattern of ice motion in the Arctic Ocean, and the proximity of the ULS moorings to the ice edge. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Kwok, R (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. EM ron.kwok@jpl.nasa.gov RI Kwok, Ron/A-9762-2008 OI Kwok, Ron/0000-0003-4051-5896 NR 20 TC 124 Z9 126 U1 1 U2 13 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9275 EI 2169-9291 J9 J GEOPHYS RES-OCEANS JI J. Geophys. Res.-Oceans PD JAN 6 PY 2004 VL 109 IS C1 AR C01009 DI 10.1029/2003JC001785 PG 14 WC Oceanography SC Oceanography GA 765ML UT WOS:000188287300002 ER PT J AU Adrian, ML Gallagher, DL Avanov, LA AF Adrian, ML Gallagher, DL Avanov, LA TI IMAGE EUV observation of radially bifurcated plasmaspheric features: First observations of a possible standing ULF waveform in the inner magnetosphere SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article DE plasmasphere; inner magnetosphere; magnetospheric configuration and dynamics; MHD waves and instabilities; solar wind/magnetosphere interactions ID EXTREME-ULTRAVIOLET IMAGER; SATELLITE-OBSERVATIONS; EARTHS MAGNETOSPHERE; PLASMAPAUSE; HELIUM; 304-A; KNEE; HE AB We present EUV observations of the plasmasphere from 1938 to 2211 UT on 28 June 2000 characterized by the presence of bifurcated radial enhancements of the He+ plasma distribution in the nightside sector. These features remain stable throughout the period of observation and are found to move about the Earth at 67% of the corotation rate. Two-dimensional simulation of the plasmasphere assuming the presence of an azimuthal standing wave patterns at L = 1.8 and 2.5 suggests that the organization of the outer plasmasphere is the result of convective motion driven by a ULF standing wave. Preliminary analysis of ground-based magnetometer data provided by the IMAGE magnetometer network during the period of EUV observation indicates the presence of several narrow-frequency oscillations extending down to 0.68 mHz, consistent with simulation results. Similar narrow-frequency features are found in preliminary analysis of ACE Solar Wind Electron Proton Alpha Monitor (SWEPAM) bulk solar wind velocity data. We speculate that the observed radial He+ enhancements of the nightside plasmasphere may be the result of a nonresonant oscillation driven by the solar wind. C1 Univ Alabama, Ctr Space Plasma & Aeron Res, Huntsville, AL 35899 USA. NASA, George C Marshall Space Flight Ctr, Sci Directorate, Huntsville, AL 35812 USA. RP Adrian, ML (reprint author), Univ Alabama, Ctr Space Plasma & Aeron Res, Huntsville, AL 35899 USA. EM mark.l.adrian@msfc.nasa.gov; dennis.gallagher@msfc.nasa.gov NR 26 TC 17 Z9 18 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 JAN 6 PY 2004 VL 109 IS A1 AR A01203 DI 10.1029/2003JA009974 PG 13 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 765MR UT WOS:000188287800004 ER PT J AU Manchester, WB Gombosi, TI Roussev, I De Zeeuw, DL Sokolov, IV Powell, KG Toth, G Opher, M AF Manchester, WB Gombosi, TI Roussev, I De Zeeuw, DL Sokolov, IV Powell, KG Toth, G Opher, M TI Three-dimensional MHD simulation of a flux rope driven CME SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article DE magnetohydrodynamics; Sun; coronal mass ejection ID CORONAL MASS EJECTIONS; MAGNETIC-FIELD; SOLAR-WIND; ALFVEN WAVES; SHOCK-WAVE; EVOLUTION; FLARES; MODEL; PROPAGATION; STREAMER AB We present a three-dimensional (3-D) numerical ideal magnetohydrodynamics (MHD) model, describing the time-dependent expulsion of plasma and magnetic flux from the solar corona that resembles a coronal mass ejection (CME). We begin by developing a global steady-state model of the corona and solar wind that gives a reasonable description of the solar wind conditions near solar minimum. The model magnetic field possesses high-latitude coronal holes and closed field lines at low latitudes in the form of a helmet streamer belt with a current sheet at the solar equator. We further reproduce the fast and slow speed solar wind at high and low latitudes, respectively. Within this steady-state heliospheric model, conditions for a CME are created by superimposing the magnetic field and plasma density of the 3-D Gibson-Low flux rope inside the coronal streamer belt. The CME is launched by initial force imbalance within the flux rope resulting in its rapid acceleration to a speed of over 1000 km/s and then decelerates, asymptotically approaching a final speed near 600 km/s. The CME is characterized by the bulk expulsion of similar to10(16) g of plasma from the corona with a maximum of similar to5 x 10(31) ergs of kinetic energy. This energy is derived from the free magnetic energy associated with the cross-field currents, which is released as the flux rope expands. The dynamics of the CME are followed as it interacts with the bimodal solar wind. We also present synthetic white-light coronagraph images of the model CME, which show a two-part structure that can be compared with coronagraph observations of CMEs. C1 Univ Michigan, Ctr Space Environm Modeling, Ann Arbor, MI 48109 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Eotvos Lorand Univ, Dept Atom Phys, H-1117 Budapest, Hungary. RP Manchester, WB (reprint author), Univ Michigan, Ctr Space Environm Modeling, 2455 Hayward St, Ann Arbor, MI 48109 USA. EM chipm@umich.edu; tamas@umich.edu; iroussev@umich.edu; darrens@umich.edu; igorsok@umich.edu; powell@engin.umich.edu; gtoth@hermes.elte.hu; merav.opher@jpl.nasa.gov RI Roussev, Ilia/E-9141-2011; De Zeeuw, Darren/F-3667-2011; Manchester, Ward/I-9422-2012; Gombosi, Tamas/G-4238-2011; Toth, Gabor/B-7977-2013; Sokolov, Igor/H-9860-2013; OI Gombosi, Tamas/0000-0001-9360-4951; Toth, Gabor/0000-0002-5654-9823; Sokolov, Igor/0000-0002-6118-0469; Powell, Kenneth/0000-0002-3708-8814 NR 58 TC 108 Z9 109 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-SPACE JI J. Geophys. Res-Space Phys. PD JAN 6 PY 2004 VL 109 IS A1 AR A01102 DI 10.1029/2002JA009672 PG 17 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 765MR UT WOS:000188287800001 ER PT J AU Reinisch, BW Huang, X Song, P Green, JL Fung, SF Vasyliunas, VM Gallagher, DL Sandel, BR AF Reinisch, BW Huang, X Song, P Green, JL Fung, SF Vasyliunas, VM Gallagher, DL Sandel, BR TI Plasmaspheric mass loss and refilling as a result of a magnetic storm SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article DE plasmasphere; magnetic storm; plasmasphere refilling; plasmasphere depletion; plasmasphere model ID RADIO PLASMA IMAGER; ION COMPOSITION MEASUREMENTS; EXTREME-ULTRAVIOLET IMAGER; ELECTRON-DENSITY; FIELD LINES; MODEL; MAGNETOSPHERE; DYNAMICS; PROFILES; MOTION AB Using the sounding measurements from the radio plasma imager on IMAGE and a plasma density inversion algorithm, we derive the plasma density profiles along the magnetic field in a few L shells every 14 hours at magnetic local noon before, during, and after the 31 March 2001 magnetic storm. An empirical model of the plasmaspheric plasma density distribution is derived as a reference using the measurements before the storm. During the storm the equatorial plasma was substantially depleted in a range of L shells. The flux tubes were refilled after the storm. The filling ratio, the equatorial plasma density normalized by its quiet time value before the storm, is introduced to assess the time evolution of the depletion and refilling processes. The depletion, more than two thirds of the quiet time content, appeared to occur rather quickly after the storm onset, as determined by the limited temporal resolution of the measurements. The refilling proceeded, although more slowly than the depletion process, significantly faster than the theoretical prediction of a 3-day timescale. Dynamic structures are observed in situ and confirmed by the extreme ultraviolet imager (EUV) measurements. C1 Univ Massachusetts Lowell, Environm Earth & Atmospher Sci Dept, Ctr Atmospher Res, Lowell, MA 01854 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. Max Planck Inst Aeron, D-37191 Katlenburg Lindau, Germany. NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35803 USA. Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA. RP Reinisch, BW (reprint author), Univ Massachusetts Lowell, Environm Earth & Atmospher Sci Dept, Ctr Atmospher Res, 600 Suffolk St, Lowell, MA 01854 USA. EM bodo_reinisch@uml.edu; paul_song@uml.edu; green@mail630.gsfc.nasa.gov; fung@nssdca.gsfc.nasa.gov; vasyliunas@linmpi.mpg.de; dennis.gallagher@msfc.nasa.gov; sandel@arizona.edu RI Fung, Shing/F-5647-2012 NR 34 TC 50 Z9 50 U1 1 U2 7 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0148-0227 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD JAN 6 PY 2004 VL 109 IS A1 AR A01202 DI 10.1029/2003JA009948 PG 11 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 765MR UT WOS:000188287800003 ER PT J AU Zesta, E Sibeck, DG AF Zesta, E Sibeck, DG TI A detailed description of the solar wind triggers of two dayside transients: Events of 25 July 1997 SO JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS LA English DT Article DE dayside transients; traveling convection vortices; hot flow anomaly; foreshock cavities; solar wind triggering ID INTERPLANETARY MAGNETIC-FIELD; TRAVELING CONVECTION VORTICES; EARTHS BOW SHOCK; SUDDEN CHANGES; MAGNETOPAUSE; GENERATION; SPACECRAFT; DISCONTINUITIES; PLASMA; WAVES AB Traveling Convection Vortices (TCVs), a specific type of dayside transient event, offer a good opportunity to study the modes of interaction between the solar wind, bow shock and the magnetosphere/ionosphere system. We study here in detail the solar wind triggers of two TCV events that occurred at 1500 UT and 1835 UT on 25 July 1997. During these two events there was a fortuitous conjunction of four solar wind monitors near the Earth's magnetosphere. We were able to identify the exact solar wind discontinuity that triggered each ground TCV. We found that the 1500 UT TCV was triggered by the density (and thus dynamic pressure) enhancement accompanying a tangential discontinuity. We were able to determine the orientation of the discontinuity plane and thus predict, in good agreement with observations, the propagation of the discontinuity between the four spacecraft as well as the propagation of the transient in the magnetosphere (geosynchronous) and ionosphere. The ground transient was generated in the early afternoon local time and then propagated westward, first toward local noon and then away from noon toward dawn. The 1835 UT TCV, which was stronger, was triggered by a more complicated solar wind discontinuity that exhibited significant spatial structure and an unusual propagation pattern. A detailed analysis of the orientation of the discontinuity fronts explained the propagation of the discontinuity in the solar wind. Even though the discontinuity did not carry a significant dynamic pressure enhancement, it had the properties required to generate a hot flow anomaly (HFA) or a foreshock cavity at the bow shock. The corresponding pressure reduction in the magnetosheath interacted with the magnetosphere to generate the transient near local noon that propagates eastward toward dusk. Geosynchronous observations confirm these conclusions. To strengthen our conclusions, we compared the discontinuity that triggered the ground TCV event with four other discontinuities that occurred in the same 2-hour window. We found that none of the other four discontinuities carried significant dynamic pressure enhancements or had properties required to create a HFA at the bow shock. They did not trigger detectable transients on the ground. It thus seems that TCVs can be triggered by solar wind discontinuities that either carry dynamic pressure enhancements (or alternatively reductions) or by discontinuities that create HFAs or foreshock cavities at the bow shock. C1 Univ Calif Los Angeles, Dept Atmospher Sci, Los Angeles, CA 90095 USA. NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Zesta, E (reprint author), Univ Calif Los Angeles, Dept Atmospher Sci, 7127 Math Sci,Box 951565, Los Angeles, CA 90095 USA. EM ezesta@atmos.ucla.edu; dsibeck@lepvax.gsfc.nasa.gov RI Sibeck, David/D-4424-2012 NR 28 TC 2 Z9 2 U1 0 U2 0 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-9380 EI 2169-9402 J9 J GEOPHYS RES-SPACE JI J. Geophys. Res-Space Phys. PD JAN 6 PY 2004 VL 109 IS A1 AR A01201 DI 10.1029/2003JA009864 PG 20 WC Astronomy & Astrophysics SC Astronomy & Astrophysics GA 765MR UT WOS:000188287800002 ER PT J AU Luck, GW Ricketts, TH Daily, GC Imhoff, M AF Luck, GW Ricketts, TH Daily, GC Imhoff, M TI Alleviating spatial conflict between people and biodiversity SO PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA LA English DT Article ID CAPE FLORISTIC REGION; HUMAN-POPULATION; RESERVE SIZE; SOUTH-AFRICA; CONSERVATION; EXTINCTION; DIVERSITY; PATTERNS; DEFORESTATION; HOTSPOTS AB Human settlements are expanding in species-rich regions and pose a serious threat to biodiversity conservation. We quantify the degree to which this threat manifests itself in two contrasting continents, Australia and North America, and suggest how it can be substantially alleviated. Human population density has a strong positive correlation with species richness in Australia for birds, mammals, amphibians, and butterflies (but not reptiles) and in North America for all five taxa. Nevertheless, conservation investments could secure locations that harbor almost all species while greatly reducing overlap with densely populated regions. We compared two conservation-planning scenarios that each aimed to represent all species at least once in a minimum set of sampling sites. The first scenario assigned equal cost to each site (ignoring differences in human population density); the second assigned a cost proportional to the site's human population density. Under the equal-cost scenario, 13-40% of selected sites occurred where population density values were highest (in the top decile). However, this overlap was reduced to as low as 0%, and in almost all cases to < 10%, under the population-cost scenario, when sites of high population density were avoided where possible. Moreover, this reduction of overlap was achieved with only small increases in the total amount of area requiring protection. As densely populated regions continue to expand rapidly and drive up land values, the strategic conservation investments of the kind highlighted in our analysis are best made now. C1 Charles Sturt Univ, Johnstone Ctr, Albury, NSW 2640, Australia. Stanford Univ, Ctr Conservat Biol, Stanford, CA 94305 USA. World Wildlife Fund, Conservat Sci Program, Washington, DC 20037 USA. NASA, Goddard Space Flight Ctr, Biospher Sci Branch, Terr Phys Lab, Greenbelt, MD 20771 USA. RP Luck, GW (reprint author), Charles Sturt Univ, Johnstone Ctr, POB 789, Albury, NSW 2640, Australia. EM galuck@csu.edu.au OI Luck, Gary/0000-0002-7266-5568 NR 43 TC 109 Z9 113 U1 5 U2 43 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 JAN 6 PY 2004 VL 101 IS 1 BP 182 EP 186 DI 10.1073/pnas.2237148100 PG 5 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 761VY UT WOS:000187937200035 PM 14681554 ER PT J AU Boykin, TB Klimeck, G Eriksson, MA Friesen, M Coppersmith, SN von Allmen, P Oyafuso, F Lee, S AF Boykin, TB Klimeck, G Eriksson, MA Friesen, M Coppersmith, SN von Allmen, P Oyafuso, F Lee, S TI Valley splitting in strained silicon quantum wells SO APPLIED PHYSICS LETTERS LA English DT Article ID INVERSION-LAYERS; MAGNETIC-FIELD; HETEROSTRUCTURES; SURFACES; STATES AB A theory based on localized-orbital approaches is developed to describe the valley splitting observed in silicon quantum wells. The theory is appropriate in the limit of low electron density and relevant for quantum computing architectures. The valley splitting is computed for realistic devices using the quantitative nanoelectronic modeling tool NEMO. A simple, analytically solvable tight-binding model reproduces the behavior of the splitting in the NEMO results and yields much physical insight. The splitting is in general nonzero even in the absence of electric field in contrast to previous works. The splitting in a square well oscillates as a function of S, the number of layers in the quantum well, with a period that is determined by the location of the valley minimum in the Brillouin zone. The envelope of the splitting decays as S-3. The feasibility of observing such oscillations experimentally in Si/SiGe heterostructures is discussed. (C) 2004 American Institute of Physics. C1 Univ Alabama, Dept Elect & Comp Engn, Huntsville, AL 35899 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. Univ Wisconsin, Dept Phys, Madison, WI 53706 USA. RP Boykin, TB (reprint author), Univ Alabama, Dept Elect & Comp Engn, Huntsville, AL 35899 USA. RI Klimeck, Gerhard/A-1414-2012 OI Klimeck, Gerhard/0000-0001-7128-773X NR 27 TC 97 Z9 98 U1 2 U2 15 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 JAN 5 PY 2004 VL 84 IS 1 BP 115 EP 117 DI 10.1063/1.1637718 PG 3 WC Physics, Applied SC Physics GA 759BH UT WOS:000187717600039 ER PT J AU Horvath, A Davies, R AF Horvath, A Davies, R TI Anisotropy of water cloud reflectance: A comparison of measurements and 1D theory SO GEOPHYSICAL RESEARCH LETTERS LA English DT Article ID SOLAR ZENITH ANGLE; OPTICAL-THICKNESS; DEPENDENCE; POLDER; SCATTERING; RETRIEVALS; BIASES; MODELS AB Bi-directional reflectances of marine liquid water clouds, as measured by the Multiangle Imaging SpectroRadiometer ( MISR), are compared with plane-parallel radiative transfer model calculations. We define an angular consistency test that requires measured and modeled radiances to agree within +/- 5% for all chosen view angles for the observations to be classified as plane-parallel. When all nine MISR angles are used at the full 275 m resolution, 1 in 6 pixels (17%) pass the test. There is a slight dependence on effective radius R-e, with R-e = 8 mum resulting in the highest pass rate. As the resolution is degraded, clouds appear more plane-parallel, and the passing rate increases to 38% at the coarsest 17.6 km scale. The passing rate quickly decreases as the number of angles used in the angular test increases. Requiring a match at only the nadir and two near-nadir angles immediately eliminates half of the full resolution pixels. C1 Univ Arizona, Dept Atmospher Sci, Tucson, AZ 85721 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Horvath, A (reprint author), Univ Arizona, Dept Atmospher Sci, POB 210081, Tucson, AZ 85721 USA. EM horvath@atmo.arizona.edu; roger@mail-misr.jpl.nasa.gov RI Horvath, Akos/A-2453-2008; Davies, Roger/D-4296-2009 OI Horvath, Akos/0000-0002-5860-2368; Davies, Roger/0000-0002-2991-0409 NR 22 TC 23 Z9 24 U1 0 U2 6 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 0094-8276 J9 GEOPHYS RES LETT JI Geophys. Res. Lett. PD JAN 3 PY 2004 VL 31 IS 1 AR L01102 DI 10.1029/2003GL018386 PG 4 WC Geosciences, Multidisciplinary SC Geology GA 765KW UT WOS:000188283400002 ER PT J AU Ahmad, Z Bhartia, PK Krotkov, N AF Ahmad, Z Bhartia, PK Krotkov, N TI Spectral properties of backscattered UV radiation in cloudy atmospheres SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE top-of-atmosphere UV reflectance; UV reflectance and plane-parallel cloud model; TOMS' top-of-the-atmosphere reflectance ID OZONE MONITORING EXPERIMENT; SATELLITE MEASUREMENTS; TROPOSPHERIC OZONE; GOME; SCATTERING; RETRIEVAL; SPECTROMETER; ALGORITHM; SNOW; TOMS AB [1] We use a Plane-Parallel Cloud (PPC) model to illustrate how Mie scattering from cloud particles interacts with Rayleigh scattering in the atmosphere and produces a complex wavelength dependence in the top-of-the-atmosphere (TOA) reflectances measured by satellite instruments that operate in the ultraviolet (UV) part of the spectrum. Comparisons of the PPC-model-derived spectral dependence of reflectances with the Total Ozone Mapping Spectrometer ( TOMS) measurements show surprisingly good agreement over a wide range of observational conditions. The PPC model results also are compared with the results of two other cloud models: Lambert Equivalent Reflectivity ( LER) and Modified LER (MLER) that have been used to analyze satellite data in the UV. These models assume that clouds are opaque Lambertian reflectors rather than Mie scattering particles. Although one of these models ( MLER) can be adjusted to agree reasonably well with the TOMS data, the adjustments are somewhat arbitrary and may not be suitable for interpreting satellite data if one desires high accuracy. We also use the PPC model to illustrate how clouds can perturb tropospheric O-3 absorption in complex ways that cannot be explained by models that treat them as reflecting surfaces rather than as volume scatterers. C1 Sci & Data Syst Inc, Silver Spring, MD USA. NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. Univ Maryland Baltimore Cty, Goddard Earth Sci & Technol Ctr, Baltimore, MD 21228 USA. RP Ahmad, Z (reprint author), Sci Syst & Applicat Inc, 16509 Copperstrip Lane, Silver Spring, MD 20906 USA. EM ahmad@qhearts.gsfc.nasa.gov; pawan.k.bhartia@nasa.gov; krotkov@chescat.gsfc.nasa.gov RI Krotkov, Nickolay/E-1541-2012 OI Krotkov, Nickolay/0000-0001-6170-6750 NR 33 TC 39 Z9 39 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 JAN 3 PY 2004 VL 109 IS D1 AR D01201 DI 10.1029/2003JD003395 PG 11 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 765LB UT WOS:000188284000001 ER PT J AU Rinsland, CP McHugh, MJ Irion, FW AF Rinsland, CP McHugh, MJ Irion, FW TI Lower stratospheric densities from solar occultation measurements of continuum absorption near 2400 cm(-1) SO JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES LA English DT Article DE continuum; infrared; occultation ID COLLISION-INDUCED ABSORPTION; ATMOS EXPERIMENT; TEMPERATURE-DEPENDENCE; SHUTTLE MISSIONS; SPECTRA; SPECTROSCOPY; SPACE; BAND; EXTINCTION; INSTRUMENT AB [1] Continuous absorption in the atmospheric window near 2400 cm(-1) has been analyzed from infrared solar occultation spectra recorded by the Atmospheric Trace Molecule Spectroscopy (ATMOS) Fourier transform spectrometer at 0.01 cm(-1) spectral resolution during its 4 shuttle flights between 1985 and 1994. The spring and autumn measurements were recorded over a wide range of temperatures and sulfate aerosol loadings. We used the ratio of the transmissions in microwindows at 2415 cm(-1) and 2501 cm(-1) as a measure of the underlying continuum absorption in the spectra. This ratio decreases from 1.0 to 0.0 as the tangent point density increases from 5 x 10(17) to 100 x 10(17) molecules cm(-3) (altitudes similar to 10 - 30 km). Attenuation in both microwindows is due to overlapping absorptions by the fundamental N-2 collision-induced band and distant sub-Lorentzian wings of CO2 lines from the strong nu(3) fundamental band. Optical depths for both N-2 and CO2 absorption are proportional to the square of the air density at constant temperature. These microwindows provide high sensitivity to density and low sensitivity to temperature in the lower stratosphere. Stratospheric transmission ratios from all 4 missions are fitted with a single parameter as a function of tangent point density with a root-mean square residual of similar to 1%. Corresponding densities from this fit agree with ATMOS version 3 densities to similar to2.3% in the region of good sensitivity at 2 x 10(18) to 8 x 10(18) molecules cm(-3) (similar to 12 - 20 km altitude). The measured transmission ratio versus density relation has been compared with calculations from temperature-dependent laboratory measurements for both the N-2 and CO2 continua. Simulation of the ATMOS spectra based on these laboratory measurements also predict a globally compact relation between the transmission ratio and density but differs from the empirically-determined relation by up to 7% in the lower stratosphere. C1 NASA, Langley Res Ctr, Atmospher Sci Competency, Hampton, VA 23681 USA. GATS Inc, Newport News, VA 23606 USA. CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Rinsland, CP (reprint author), NASA, Langley Res Ctr, Atmospher Sci Competency, 21 Langley Blvd,Mail Stop 402, Hampton, VA 23681 USA. EM curtis.p.rinsland@nasa.gov; m.j.mchugh@gats-inc.com; bill.irion@jpl.nasa.gov OI Mahieu, Emmanuel/0000-0002-5251-0286 NR 33 TC 15 Z9 15 U1 0 U2 1 PU AMER GEOPHYSICAL UNION PI WASHINGTON PA 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA SN 2169-897X J9 J GEOPHYS RES-ATMOS JI J. Geophys. Res.-Atmos. PD JAN 2 PY 2004 VL 109 IS D1 AR D01301 DI 10.1029/2003JD003803 PG 8 WC Meteorology & Atmospheric Sciences SC Meteorology & Atmospheric Sciences GA 765LA UT WOS:000188283900001 ER PT J AU van der Werf, GR Randerson, JT Collatz, GJ Giglio, L Kasibhatla, PS Arellano, AF Olsen, SC Kasischke, ES AF van der Werf, GR Randerson, JT Collatz, GJ Giglio, L Kasibhatla, PS Arellano, AF Olsen, SC Kasischke, ES TI Continental-scale partitioning of fire emissions during the 1997 to 2001 El Nino/La Nina period SO SCIENCE LA English DT Article ID CARBON-CYCLE; INTERANNUAL VARIABILITY; FOREST-FIRES; GROWTH-RATE; MODEL; CO; DELTA-C-13; DIOXIDE; METHANE; ENSO AB During the 1997 to 1998 El Nino, drought conditions triggered widespread increases in. re activity, releasing CH(4) and CO(2) to the atmosphere. We evaluated the contribution of. res from different continents to variability in these greenhouse gases from 1997 to 2001, using satellite-based estimates of. re activity, biogeochemical modeling, and an inverse analysis of atmospheric CO anomalies. During the 1997 to 1998 El Nino, the. re emissions anomaly was 2.1 +/- 0.8 petagrams of carbon, or 66 +/- 24% of the CO(2) growth rate anomaly. The main contributors were Southeast Asia (60%), Central and South America (30%), and boreal regions of Eurasia and North America (10%). C1 Foreign Agr Serv, USDA, NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. CALTECH, Dept Geol & Planetary Sci, Pasadena, CA 91125 USA. CALTECH, Div Engn & Appl Sci, Pasadena, CA 91125 USA. NASA, Goddard Space Flight Ctr, Sci & Syst Applicat Inc, Greenbelt, MD 20771 USA. Duke Univ, Nicholas Sch Environm & Earth Sci, Durham, NC 27708 USA. Univ Maryland, Dept Geog, College Pk, MD 20742 USA. RP van der Werf, GR (reprint author), Foreign Agr Serv, USDA, NASA, Goddard Space Flight Ctr, Code 923,Greenbelt Rd, Greenbelt, MD 20771 USA. EM guido@ltpmailx.gsfc.nasa.gov RI Arellano, Avelino, Jr./F-5674-2010; Kasibhatla, Prasad/A-2574-2010; collatz, george/D-5381-2012; van der Werf, Guido/M-8260-2016; OI van der Werf, Guido/0000-0001-9042-8630; Kasibhatla, Prasad/0000-0003-3562-3737 NR 30 TC 335 Z9 351 U1 6 U2 59 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 JAN 2 PY 2004 VL 303 IS 5654 BP 73 EP 76 DI 10.1126/science.1090753 PG 4 WC Multidisciplinary Sciences SC Science & Technology - Other Topics GA 758YU UT WOS:000187710600035 PM 14704424 ER PT B AU Some, RR AF Some, RR BE Martin, DC TI High performance computing in dependable space systems SO 10TH IEEE PACIFIC RIM INTERNATIONAL SYMPOSIUM ON DEPENDABLE COMPUTING, PROCEEDINGS LA English DT Proceedings Paper CT 10th IEEE Pacific Rim International Symposium on Dependable Computing (PRDC 2004) CY MAR 03-05, 2004 CL Papeete, FR POLYNESIA SP IEEE Comp Soc TC Fault Tolerant Comp, LAAS CNRS, IFIP WG 10 4 C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 2 TC 0 Z9 0 U1 0 U2 0 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 USA BN 0-7695-2076-6 PY 2004 BP 335 EP 340 DI 10.1109/PRDC.2004.1276584 PG 6 WC Computer Science, Hardware & Architecture; Computer Science, Software Engineering; Computer Science, Theory & Methods SC Computer Science GA BY73P UT WOS:000189450600035 ER PT B AU Hihn, J Lum, KT AF Hihn, J Lum, KT GP ieee computer society TI Improving software size estimates by using probabilistic pairwise comparison matrices SO 10TH INTERNATIONAL SYMPOSIUM ON SOFTWARE METRICS, PROCEEDINGS LA English DT Proceedings Paper CT 10th International Symposium on Software Metrics CY SEP 11-17, 2004 CL Chicago, IL SP IEEE Comp Soc, TCSE AB The Pairwise Comparison technique is a general purpose estimation approach for capturing expert judgment. This approach can be generalized to a probabilistic version using Monte Carlo methods to produce estimates of size distributions. The probabilistic pairwise comparison technique enables the estimator to systematically incorporate both estimation uncertainty as well as any uncertainty that arises from using multiple historical analogies as reference modules. In addition to describing the methodology, the results of the case study are also included. This paper is an extension of the work presented in [1] and will show how the original software size estimates compared to the actual delivery size. It will also describe the techniques used to modify the approach based on lessons learned. The results because they are based on only one case do not validate the effectiveness of the proposed approach but are suggestive that the technique can be effective and support the conclusion that further research is worth pursuing. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Hihn, J (reprint author), CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. NR 13 TC 2 Z9 2 U1 0 U2 0 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 USA BN 0-7695-2129-0 PY 2004 BP 140 EP 150 DI 10.1109/METRIC.2004.1357898 PG 11 WC Computer Science, Software Engineering SC Computer Science GA BBB23 UT WOS:000224489900013 ER PT B AU Larchev, GV Lohn, JD AF Larchev, GV Lohn, JD GP ieee computer society TI Hardware-in-the-loop evolution of a 3-bit multiplier SO 12TH ANNUAL IEEE SYMPOSIUM ON FIELD-PROGRAMMABLE CUSTOM COMPUTING MACHINES, PROCEEDINGS SE Annual IEEE Symposium on Field-Programmable Custom Computing Machines LA English DT Proceedings Paper CT 12th Annual IEEE Symposium on Field-Programmable Custom Computing Machines CY APR 20-23, 2004 CL Napa, CA SP IEEE Comp Soc, TC Comp Architecture C1 QSS Grp Inc, Ames Res Ctr, NASA, Moffett Field, CA 94035 USA. RP Larchev, GV (reprint author), QSS Grp Inc, Ames Res Ctr, NASA, MS 269-3, Moffett Field, CA 94035 USA. EM glarchev@mail.arc.nasa.gov; jlohn@mail.arc.nasa.gov NR 4 TC 0 Z9 1 U1 0 U2 0 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 USA BN 0-7695-2230-0 J9 ANN IEEE SYM FIELD P PY 2004 BP 277 EP 278 DI 10.1109/FCCM.2004.39 PG 2 WC Computer Science, Hardware & Architecture; Computer Science, Theory & Methods SC Computer Science GA BBE65 UT WOS:000225131700029 ER PT S AU Brown, LR Naumenko, OV Polovtseva, ER Sinitsa, LN AF Brown, LR Naumenko, OV Polovtseva, ER Sinitsa, LN BE Sinitsa, LN TI Hydrogen sulfide absorption spectrum in the 5700-6600 cm(-1) spectral region SO 14TH SYMPOSIUM ON HIGH-RESOLUTION MOLECULAR SPECTROSCOPY SE PROCEEDINGS OF THE SOCIETY OF PHOTO-OPTICAL INSTRUMENTATION ENGINEERS (SPIE) LA English DT Proceedings Paper CT 14th Symposium on High-Resolution Molecular Spectroscopy CY JUL 06-11, 2003 CL Kransnoyarsk, RUSSIA SP Opt Soc Amer, SPIE Russia Chapter, Russian Acad Sci, Siberian Branch, Russian Acad Sci, Inst Atmospher Opt DE high resolution spectra; effective Hamiltonians; spectra assignment and modeling ID INFRARED-SPECTRUM; H2S; (H2S)-S-32; CONSTANTS AB High resolution FT absorption spectrum of H2S from 5700 to 6600 cm(-1) was experimentally recorded and theoretically treated. As a result of the spectrum assignment I 100 precise energy levels were derived for the 2nd hexad interacting states of (H2S)-S-32, (H2S)-S-33, and (H2S)-S-34 isotope species including the highly excited (050) state. These energy levels were modeled using Watson-type rotational Hamiltonian and taking into account Coriolis, Darling-Dennison and weak Fermi-resonance interactions inside polyad of interacting states. An average accuracy of the energy levels fitting is of 0.0019 cm(-1) for the main isotope species. New evaluation of the band origin of the dark (012) state E-v = 6385.299 cm(-1) is obtained from the fitting process which agrees well with recent prediction by Naumenko et al. (J. Mol. Spectrosc. 50, 100-110 (2001)). Precise line intensity measurements were performed for more than 1200 absorption lines with accuracy varying from 1 to 7%. These intensities were modeled within 3.3% using wavefunctions derived in the process of the energy levels fitting. The transformed transition moment expansion with 29 terms for 1088 intensities was used. Detailed and accurate H2S absorption line list was generated in the HITRAN format for the analyzed spectral region. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Brown, LR (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 10 TC 9 Z9 9 U1 0 U2 2 PU SPIE-INT SOC OPTICAL ENGINEERING PI BELLINGHAM PA 1000 20TH ST, PO BOX 10, BELLINGHAM, WA 98227-0010 USA SN 0277-786X BN 0-8194-5219-X J9 P SOC PHOTO-OPT INS PY 2004 VL 5311 BP 59 EP 67 DI 10.1117/12.545192 PG 9 WC Spectroscopy SC Spectroscopy GA BY54Z UT WOS:000189406000007 ER PT B AU Feather, MS AF Feather, MS GP ieee computer society TI Towards a unified approach to the representation of, and reasoning with, probabilistic risk information about software and its system interface SO 15TH INTERNATIONAL SYMPOSIUM ON SOFTWARE RELIABILITY ENGINEERING, PROCEEDINGS LA English DT Proceedings Paper CT 15th International Symposium on Software Reliability Engineering CY NOV 02-05, 2004 CL St Malo, FRANCE SP IEEE Comp Soc, Reliabil Soc, IRISA, cigital, Microsoft, france telecom R&D, Thales, IBM, CNRS, DGA, INRIA, Metropole Rennes, Bretagne Reg, Univ Rennes DE FMEA; FMECA; SFMECA; FTA; PRA; risk-informed decision-making; cost-benefit tradeoffs; probabilistic risk reduction; failure modes AB Early risk assessment is key in planning the development of systems, including systems that involve software. Such risk assessment needs a combination of the following elements: Severity estimates for the potential effects of failures, and likelihood estimates for their causes Fault trees that link causes to failures Efficacy estimates of design and process steps towards reducing risk Distinctions between preventing, alleviating and detecting (thereafter removing), risks Risk preventions that have potential side effects of themselves introducing risks The paper shows a unified approach that accommodates all these elements. The approach combines fault trees (from Probabilistic Risk Assessment methods) with explicit treatment of risk mitigations (a generalization of the notion of a "detection" seen in FMECA analyses). Fault trees capture the causal relationships by which failure mechanisms may combine to lead to failure modes. Risk mitigations encompass (and distinguish among) options to prevent risks, detect risks, and alleviate risks (i.e., decrease their impact should they occur). This approach has been embodied in extensions to a JPL-developed risk assessment tool, and is illustrated here on software risk assessment information drawn from an actual project's software system FMECA (Failure Modes, Effects and Criticality Analysis). Since its elements are typical of risk assessment of software and its system interface, the findings should be relevant to a wide range of software systems. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Feather, MS (reprint author), CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. NR 20 TC 4 Z9 4 U1 1 U2 4 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 USA BN 0-7695-2215-7 PY 2004 BP 391 EP 402 DI 10.1109/ISSRE.2004.42 PG 12 WC Computer Science, Software Engineering SC Computer Science GA BBJ03 UT WOS:000225734400034 ER PT B AU Katz, DS Bergou, A Berriman, GB Block, GL Collier, J Curkendall, DW Good, J Husman, L Jacob, JC Laity, A Li, PP Miller, C Prince, T Siegel, H Williams, R AF Katz, DS Bergou, A Berriman, GB Block, GL Collier, J Curkendall, DW Good, J Husman, L Jacob, JC Laity, A Li, PP Miller, C Prince, T Siegel, H Williams, R BE Hatzopoulos, M Manolopoulos, Y TI Accessing and visualizing scientific spatiotemporal data SO 16TH INTERNATIONAL CONFERENCE ON SCIENTIFIC AND STATISTICAL DATABASE MANAGEMENT, PROCEEDINGS LA English DT Proceedings Paper CT 16th International Conference on Scientific and Statistical Database Management CY JUN 21-23, 2004 CL Santorini, GREECE SP Emporiki Bank, Microsoft, Alpha Bank AB This paper discusses work done by JPL's Parallel Applications Technologies Group in helping scientists access and visualize very large data sets through the use of multiple computing resources, such as parallel supercomputers, clusters, and grids. These tools do one or more of the following tasks: visualize local data sets for local users, visualize local data sets for remote users, and access and visualize remote data sets. The tools are used for various types of data, including remotely sensed image data, digital elevation models, astronomical surveys, etc. The paper attempts to pull some common elements out of these tools that may be useful for others who have to work with similarly large data sets. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Katz, DS (reprint author), CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. EM Daniel.S.Katz@jpl.nasa.gov OI Katz, Daniel S./0000-0001-5934-7525 NR 12 TC 1 Z9 1 U1 0 U2 0 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 USA BN 0-7695-2146-0 PY 2004 BP 107 EP 110 PG 4 WC Computer Science, Information Systems; Computer Science, Interdisciplinary Applications SC Computer Science GA BAN45 UT WOS:000222968600012 ER PT B AU Richardson, J Green, J AF Richardson, J Green, J GP ieee computer society TI Automating traceability for generated software artifacts SO 19TH INTERNATIONAL CONFERENCE ON AUTOMATED SOFTWARE ENGINEERING, PROCEEDINGS LA English DT Proceedings Paper CT 19th IEEE International Conference on Automated Software Engineering CY SEP 20-24, 2004 CL Linz, AUSTRIA SP IEEE Comp Soc, Austrian Comp Soc, ACM SIGART, ACM SIGSOFT ID RECOVERY; CODE AB Program synthesis automatically derives programs from specifications of their behavior At a lower level, compilation automatically derives machine code from source code (i.e. from a specification of its behavior). An advantage of program synthesis/compilation, as opposed to manual coding, is that there is a direct link between the specification and the derived program. This link is, however not very fine-grained: it can be best characterized as Program is-derived-from Specification. When the generated program needs to be understood or modified, more fine-grained linking is useful. In this paper, we present a novel technique for automatically deriving traceability relations between parts of a specification and parts of the synthesized program. The technique is very lightweight and we expect it to work - with varying degrees of success - for any process in which one artifact is automatically derived from another We illustrate the generality of the technique by applying it to two kinds of automatic generation: synthesis of Kalman Filter programs from specifications using the AUTOFILTER program synthesis system, and generation of assembly language programs from C source code using the GCCC compiler We evaluate the effectiveness of the technique in the latter application. C1 NASA, Ames Res Ctr, Automated Software Engn Grp, Moffett Field, CA 94035 USA. RP NASA, Ames Res Ctr, Automated Software Engn Grp, Moffett Field, CA 94035 USA. EM julianr@email.arc.nasa.gov NR 13 TC 4 Z9 4 U1 0 U2 0 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 USA BN 0-7695-2131-2 PY 2004 BP 24 EP 33 DI 10.1109/ASE.2004.1342721 PG 10 WC Computer Science, Software Engineering SC Computer Science GA BBA31 UT WOS:000224382300004 ER PT B AU Breu, S Krinke, J AF Breu, S Krinke, J GP ieee computer society TI Aspect mining using event traces SO 19TH INTERNATIONAL CONFERENCE ON AUTOMATED SOFTWARE ENGINEERING, PROCEEDINGS LA English DT Proceedings Paper CT 19th IEEE International Conference on Automated Software Engineering CY SEP 20-24, 2004 CL Linz, AUSTRIA SP IEEE Comp Soc, Austrian Comp Soc, ACM SIGART, ACM SIGSOFT AB Aspect mining tries to identify crosscutting concerns in existing systems and thus supports the adaption to an aspect-oriented design. This paper describes the first aspect mining approach that detects crosscutting concerns in legacy systems based on dynamic analysis. The analysis uses program traces that are generated in different program executions as underlying data pool. These traces are then investigated for recurring execution patterns based on different constraints, such as the requirement that the patterns have to exist in different calling contexts in the program trace. The implemented approach was evaluated in several case studies over systems with more than 80 kLoC. The tool was able to identify automatically both existing and seeded crosscutting concerns. C1 NASA, MCT, Ames, IA USA. RP Breu, S (reprint author), NASA, MCT, Ames, IA USA. RI Krinke, Jens/E-9011-2011 OI Krinke, Jens/0000-0003-1009-2861 NR 11 TC 40 Z9 44 U1 0 U2 0 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 USA BN 0-7695-2131-2 PY 2004 BP 310 EP 315 DI 10.1109/ASE.2004.1342754 PG 6 WC Computer Science, Software Engineering SC Computer Science GA BBA31 UT WOS:000224382300037 ER PT S AU Trombka, JI Schweitzer, JS AF Trombka, JI Schweitzer, JS BE Metzler, SD TI Dual technology programs in the development of technologies for unattended and remote systems SO 2003 IEEE NUCLEAR SCIENCE SYMPOSIUM, CONFERENCE RECORD, VOLS 1-5 SE IEEE NUCLEAR SCIENCE SYMPOSIUM - CONFERENCE RECORD LA English DT Proceedings Paper CT IEEE Nuclear Science Symposium/Medical Imaging Conference CY OCT 19-25, 2003 CL Portland, OR SP IEEE, Nucl & Plasma Sci Soc AB The National Institute of Justice (NIJ) and the National Aeronautics and Space Administration's (NASA) Goddard Space Flight Center (GSFC) have teamed up to explore the use of NASA developed technologies to help criminal justice agencies and professionals investigate crimes. The objective of the program is to produce instruments and communication networks that have application within both NASA's space program and NIJ. In order to achieve the volume, weight and power constraints for instruments required by both space and terrestrial missions, it has been found necessary to incorporate solid-state x-ray, gamma ray, and neutron detectors into the system designs. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Trombka, JI (reprint author), NASA, Goddard Space Flight Ctr, Code 661, Greenbelt, MD 20771 USA. NR 3 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1082-3654 BN 0-7803-8257-9 J9 IEEE NUCL SCI CONF R PY 2004 BP 3560 EP 3563 DI 10.1109/NSSMIC.2003.1352679 PG 4 WC Nuclear Science & Technology; Imaging Science & Photographic Technology; Radiology, Nuclear Medicine & Medical Imaging SC Nuclear Science & Technology; Imaging Science & Photographic Technology; Radiology, Nuclear Medicine & Medical Imaging GA BAS86 UT WOS:000223398000791 ER PT B AU Tilton, JC AF Tilton, JC GP ieee TI Analysis of hierarchically related image segmentations SO 2003 IEEE WORKSHOP ON ADVANCES IN TECHNIQUES FOR ANALYSIS OF REMOTELY SENSED DATA LA English DT Proceedings Paper CT IEEE Workshop on Advances in Techniques for Analysis of Remotely Sensed Data held in Honor of David A Landgrebe CY OCT 27-28, 2003 CL NASA Goddard Space Flight Visitor Ctr, Greenbelt, MD SP IEEE HO NASA Goddard Space Flight Visitor Ctr DE image segmentation; image representation; segmentation hierarchy AB Described herein is an approach for producing high quality hierarchically related image segmentations and some first steps towards exploiting the information content of the segmentation hierarchy. Hierarchically related image segmentations are a set of image segmentations at different levels of detail in which the less detailed segmentations can be produced from specific merges of regions contained in the more detailed segmentations. After a general overview of other approaches to image segmentation, the Hierarchical Segmentation (HSEG) algorithm is presented, along with its recursive formulation (RHSEG). Finally, an approach is outlined for exploiting the information content from the segmentation hierarchy based on changes in region features from one hierarchical level to the next. Comparative results are presented with Landsat Thematic Mapper (TM) data. C1 NASA, Goddard Space Flight Ctr, Appl Informat Sci Branch, Greenbelt, MD 20771 USA. RP NASA, Goddard Space Flight Ctr, Appl Informat Sci Branch, Greenbelt, MD 20771 USA. EM James.C.Tilton@nasa.gov NR 12 TC 0 Z9 0 U1 1 U2 3 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-8350-8 PY 2004 BP 60 EP 69 PG 10 WC Remote Sensing SC Remote Sensing GA BAG84 UT WOS:000222142800009 ER PT B AU Koren, I Joseph, JH AF Koren, I Joseph, JH GP ieee TI Morphological component analysis for feature detection in satellite images SO 2003 IEEE WORKSHOP ON ADVANCES IN TECHNIQUES FOR ANALYSIS OF REMOTELY SENSED DATA LA English DT Proceedings Paper CT IEEE Workshop on Advances in Techniques for Analysis of Remotely Sensed Data held in Honor of David A Landgrebe CY OCT 27-28, 2003 CL NASA Goddard Space Flight Visitor Ctr, Greenbelt, MD SP IEEE HO NASA Goddard Space Flight Visitor Ctr DE classification; clustering; independent component analysis; morphological component analysis ID MINERAL DUST; CLOUDS AB A new approach to cluster analysis is proposed, namely Morphological Component Analysis (MCA), to enhance discrimination of features in multi-channel satellite images. The characterization of clusters, in this method, is morphological, unlike some of the classical cluster approaches in which the clusters are defined by their centers. By using the shape and orientation of the clusters, it is possible to define an affine transformation of the cluster space into a new one in which the selected clusters are orthogonal or better separated. Such an operation can be considered as supervised Independent Component Analysis - ICA [1]. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Koren, I (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RI Koren, Ilan/K-1417-2012 OI Koren, Ilan/0000-0001-6759-6265 NR 7 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-8350-8 PY 2004 BP 70 EP 72 PG 3 WC Remote Sensing SC Remote Sensing GA BAG84 UT WOS:000222142800010 ER PT B AU Chettri, S Campbell, W AF Chettri, S Campbell, W GP ieee TI De-noising remotely sensed digital imagery SO 2003 IEEE WORKSHOP ON ADVANCES IN TECHNIQUES FOR ANALYSIS OF REMOTELY SENSED DATA LA English DT Proceedings Paper CT IEEE Workshop on Advances in Techniques for Analysis of Remotely Sensed Data held in Honor of David A Landgrebe CY OCT 27-28, 2003 CL NASA Goddard Space Flight Visitor Ctr, Greenbelt, MD SP IEEE HO NASA Goddard Space Flight Visitor Ctr ID TRANSFORM; REMOVAL; AVIRIS AB This paper applies two recent methods to de-noise remotely sensed images - Wavelet based Markov Random Field (MRF) methods [10], Independent Component Analysis (ICA)[13] and compares them with the standard Wiener filter. In order to facilitate the continued use of these methods in remote sensing the theory behind each method is discussed in detail. Subsequently they are applied to de-noising remotely sensed images. The efficiency of each algorithm is obtained by computing the Signal to Noise Ratio (SNR) before and after de-noising. Results indicate that the MRF based methods, though slightly more complicated to program and only marginally slower than ICA de-noising, generally perform better than both ICA and Wiener filtering. The article ends by discssing future areas of research in de-noising remotely sensed images. C1 NASA, GSFC, Global Sci & Technol Inc, Greenbelt, MD 20770 USA. RP Chettri, S (reprint author), NASA, GSFC, Global Sci & Technol Inc, 7855 Walker Dr,Suite 200, Greenbelt, MD 20770 USA. NR 37 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-8350-8 PY 2004 BP 193 EP 201 PG 9 WC Remote Sensing SC Remote Sensing GA BAG84 UT WOS:000222142800029 ER PT B AU Gualtieri, JA AF Gualtieri, JA GP ieee TI Hyperspectral analysis, the support vector machine, and land and benthic habitats SO 2003 IEEE WORKSHOP ON ADVANCES IN TECHNIQUES FOR ANALYSIS OF REMOTELY SENSED DATA LA English DT Proceedings Paper CT IEEE Workshop on Advances in Techniques for Analysis of Remotely Sensed Data held in Honor of David A Landgrebe CY OCT 27-28, 2003 CL NASA Goddard Space Flight Visitor Ctr, Greenbelt, MD SP IEEE HO NASA Goddard Space Flight Visitor Ctr ID ATMOSPHERIC CORRECTION; SHALLOW WATERS; ALGORITHM AB Two different areas of current research in hyperspectral remote sensing are addressed: (1) Supervised Learning using all the hyperspectral bands as based on the recently introduced method called the Support Vector Machine. (2) Hyperspectral remote sensing in shallow water to retrieve benthic properties including depth and albedo on the sea floor. The Support Vector technique is applied to land agricultural scenes acquired by AVIRIS with up to 16 classes, and is shown to give improved results over a number of methods all applied to the same scene. Hyperspectral remote sensing in shallow water is demonstrated on an AVIRIS scene acquired in Kaneohe Bay Hawaii, where reasonable depths and bottom albedo's are retrieved. The method is based on physical modeling of the propagation of light though the atmosphere and physical modeling of the propagation of light through the water column above the sea floor. The results for shallow water remote sensing are extended by a physically realistic simulation using AVIRIS at-sensor data to model cases of spatial resolution and Signal to Noise Ratios that might exist for a hyperspectral sensor in Geo-Stationery orbit. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Gualtieri, JA (reprint author), NASA, Goddard Space Flight Ctr, Code 935, Greenbelt, MD 20771 USA. NR 36 TC 0 Z9 0 U1 1 U2 2 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-8350-8 PY 2004 BP 354 EP 363 PG 10 WC Remote Sensing SC Remote Sensing GA BAG84 UT WOS:000222142800051 ER PT B AU Salomonson, VV Wolfe, RE AF Salomonson, VV Wolfe, RE GP ieee TI MODIS geolocation approach, results and the future SO 2003 IEEE WORKSHOP ON ADVANCES IN TECHNIQUES FOR ANALYSIS OF REMOTELY SENSED DATA LA English DT Proceedings Paper CT IEEE Workshop on Advances in Techniques for Analysis of Remotely Sensed Data held in Honor of David A Landgrebe CY OCT 27-28, 2003 CL NASA Goddard Space Flight Visitor Ctr, Greenbelt, MD SP IEEE HO NASA Goddard Space Flight Visitor Ctr DE NASA; EOS; terra; aqua; MODIS; geolocation; satellite; navigation ID IMAGING SPECTRORADIOMETER MODIS; MISREGISTRATION; IMPACT AB The Moderate Resolution Imaging Spectroradiometer (MODIS) is on the NASA Earth Observing System (EOS) Terra and Aqua satellites.. The MODIS geolocation approach operationally characterizes MODIS geolocation errors and enables individual MODIS observations to be geolocated to the sub-pixel accuracies required for terrestrial global change applications. An overview of the approach, results from both missions and future work are described. C1 NASA, Goddard Space Flight Ctr, Earth Sci Directorate, Greenbelt, MD USA. RP Salomonson, VV (reprint author), NASA, Goddard Space Flight Ctr, Earth Sci Directorate, Code 900, Greenbelt, MD USA. RI Wolfe, Robert/E-1485-2012 OI Wolfe, Robert/0000-0002-0915-1855 NR 10 TC 1 Z9 1 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-8350-8 PY 2004 BP 424 EP 427 PG 4 WC Remote Sensing SC Remote Sensing GA BAG84 UT WOS:000222142800061 ER PT B AU Ting, DZY Cartoixa, X Chang, YC AF Ting, DZY Cartoixa, X Chang, YC GP ieee TI Nonmagnetic heterostructure spin devices SO 2003 INTERNATIONAL SYMPOSIUM ON COMPOUND SEMICONDUCTORS: POST-CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT 30th International Symposium on Compound Semiconductors CY AUG 25-27, 2003 CL San Diego, CA ID TRANSISTOR; RELAXATION AB We report concepts and modeling results on nonmagnetic semiconductor heterostructure spin devices, including resonant tunneling spin filters, bi-directional resonant tunneling spin pumps, and resonant spin lifetime transistors. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Ting, DZY (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 19 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-8614-0 PY 2004 BP 102 EP 107 DI 10.1109/ISCSPC.2003.1354439 PG 6 WC Engineering, Electrical & Electronic; Materials Science, Ceramics; Physics, Condensed Matter SC Engineering; Materials Science; Physics GA BBL69 UT WOS:000226028400017 ER PT S AU Wolpert, DH Bieniawski, S AF Wolpert, DH Bieniawski, S GP ieee TI Distributed control by Lagrangian steepest descent SO 2004 43RD IEEE CONFERENCE ON DECISION AND CONTROL (CDC), VOLS 1-5 SE IEEE Conference on Decision and Control LA English DT Proceedings Paper CT 43rd IEEE Conference on Decision and Control CY DEC 14-17, 2004 CL BAHAMAS SP IEEE Control Syst Soc, Honeywell, MathWorks, Natl Instruments, United Technol Res Ctr, XEROX AB Often adaptive, distributed control can be viewed as an iterated game between independent players. The coupling between the players' mixed strategies, arising as the system evolves, is determined by the system designer. Information theory tells us that the most likely joint strategy of the players, given a value of the expectation of the overall control objective function, is the minimizer of a Lagrangian function of the joint strategy. So the goal of the system designer is to speed evolution of the joint strategy to that Lagrangian minimizing point, lower the expectated value of the control objective function, and repeat. Here we discuss how to do this using local descent procedures, and thereby achieve efficient, adaptive, distributed control. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. EM dhw@ptolemy.arc.nasa.gov; stefanb@stanford.edu NR 16 TC 4 Z9 4 U1 0 U2 2 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 0743-1546 BN 0-7803-8682-5 J9 IEEE DECIS CONTR P PY 2004 BP 1562 EP 1567 DI 10.1109/CDC.2004.1430266 PG 6 WC Automation & Control Systems; Computer Science, Artificial Intelligence SC Automation & Control Systems; Computer Science GA BBO61 UT WOS:000226745601074 ER PT B AU Anantram, MP Svizhenko, A Govindan, TR AF Anantram, MP Svizhenko, A Govindan, TR GP IEEE TI Transport and electrostatics in metallic carbon nanotubes SO 2004 4TH IEEE CONFERENCE ON NANOTECHNOLOGY LA English DT Proceedings Paper CT 4th IEEE Conference on Nanotechnology CY AUG 16-19, 2004 CL Munich, GERMANY SP IEEE DE nanowires; carbon nanotubes; electronphonon scattering; inter-connects ID CURRENT-CARRYING CAPACITY; ELECTRICAL-TRANSPORT; CURRENT SATURATION AB We calculate the current and electrostatic potential drop in metallic carbon nanotube wires self-consistently, by solving the Green's function and electrostatics equations. For single wall nanotubes, we find that there are two qualitatively different regimes corresponding to low and high biases. In the low bias regime (100 mV), about one tenth of the applied voltage drops across the bulk of a nanowire, independent of the lengths considered here. The remaining nine tenths of the bias drops near the contacts, thereby creating a non linear potential drop. In the high voltage regime, the potential drops primarily across the bulk of the nanowire. The electric field at the nanotube center increases with increase in nanotube diameter for low biases. The scaling of the electric field at the center of the nanotube with length (L) is faster than 1/L (roughly 1/L(1.25-1.75)) at low biases, and 1/L at high biases. At room temperature, the low bias conductance of large diameter nanotubes is larger than 4e(2)/h due to occupation of non crossing subbands. The physics of conductance evolution with bias due to the competing factors of transmission into non crossing subbands and phonon scattering is discussed. C1 NASA, Ames Res Ctr, Ctr Nanotechnol, Moffett Field, CA 94035 USA. RP Anantram, MP (reprint author), NASA, Ames Res Ctr, Ctr Nanotechnol, Moffett Field, CA 94035 USA. EM anant@nas.nasa.gov; svizhenk@nas.nasa.gov; Tr.R.Govindan@nasa.gov NR 18 TC 0 Z9 0 U1 0 U2 2 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-8536-5 PY 2004 BP 121 EP 124 PG 4 WC Instruments & Instrumentation; Materials Science, Multidisciplinary SC Instruments & Instrumentation; Materials Science GA BBL92 UT WOS:000226085100040 ER PT S AU Diftler, MA Ambrose, RO Tyree, KS Goza, SM Huber, EL AF Diftler, MA Ambrose, RO Tyree, KS Goza, SM Huber, EL GP IEEE TI A mobile autonomous humanoid assistant SO 2004 4TH IEEE/RAS INTERNATIONAL CONFERENCE ON HUMANOID ROBOTS, VOLS 1 AND 2, PROCEEDINGS SE IEEE-RAS International Conference on Humanoid Robots LA English DT Proceedings Paper CT 4th IEEE/RAS International Conference on Humanoid Robots CY NOV 10-12, 2004 CL Santa Monica, CA SP IEEE Robot & Automat Soc, Robit Soc Japan DE dexterous robot; mobile; autonomy; hazardous environment AB A mobile autonomous humanoid robot is assisting human co-workers at the Johnson Space Center with tool handling tasks. This robot combines the upper body of the National Aeronautics and Space Administration (NASA) / Defense Advanced Research Projects Agency (DARPA) Robonaut system with a Segway (TM) Robotic Mobility Platform yielding a dexterous, maneuverable humanoid perfect for aiding human co-workers in a range of environments. This system uses stereo vision to locate human teammates and tools and a navigation system that uses laser range and vision data to follow humans while avoiding obstacles. Tactile sensors provide information to grasping algorithms for efficient tool exchanges. The autonomous architecture utilizes these pre-programmed skills to form human assistant behaviors. The initial behavior demonstrates a robust capability to assist a human by acquiring a tool from a remotely located individual and then following the human in a cluttered environment with the tool for future use. C1 NASA, Lyndon B Johnson Space Ctr, Automat Robot & Simulat Div, Houston, TX 77058 USA. RP NASA, Lyndon B Johnson Space Ctr, Automat Robot & Simulat Div, Houston, TX 77058 USA. EM diftler@jsc.nasa.gov; huber@jsc.nasa.gov NR 16 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 2164-0572 BN 0-7803-8863-1 J9 IEEE-RAS INT C HUMAN PY 2004 BP 133 EP 148 PG 16 WC Robotics SC Robotics GA BCB10 UT WOS:000228484200009 ER PT S AU Bluethmann, W Ambrose, R Diftler, M Huber, E Fagg, A Rosenstein, M Platt, R Grupen, R Breazeal, C Brooks, A Lockerd, A Peters, RA Jenkins, OC Mataric, M Bugajska, M AF Bluethmann, W Ambrose, R Diftler, M Huber, E Fagg, A Rosenstein, M Platt, R Grupen, R Breazeal, C Brooks, A Lockerd, A Peters, RA Jenkins, OC Mataric, M Bugajska, M GP IEEE TI Building an autonomous humanoid tool user SO 2004 4TH IEEE/RAS INTERNATIONAL CONFERENCE ON HUMANOID ROBOTS, VOLS 1 AND 2, PROCEEDINGS SE IEEE-RAS International Conference on Humanoid Robots LA English DT Proceedings Paper CT 4th IEEE/RAS International Conference on Humanoid Robots CY NOV 10-12, 2004 CL Santa Monica, CA SP IEEE Robot & Automat Soc, Robit Soc Japan DE humanoid robots; robonaut; dexterity; robotic tool use AB To make the transition from a technological curiosity to productive tools, humanoid robots will require key advances in many areas, including, mechanical design, sensing, embedded avionics, power, and navigation. Using the NASA Johnson Space Center's Robonaut as a testbed, the DARPA Mobile Autonomous Robot Software (MARS) Humanoids team is investigating technologies that will enable humanoid robots to work effectively with humans and autonomously work with tools. A novel learning approach is being applied that enables the robot to learn both from a remote human teleoperating the robot and an adjacent human giving instruction. When the remote human performs tasks teleoperatively, the robot learns the salient sensory-motor features to executing the task. Once learned, the task may be carried out fusing the skills required to perform the task, guided by on-board sensing. The adjacent human takes advantage of previously learned skills to sequence the execution of these skills. Preliminary results from initial experiments using a drill to tighten lug nuts on a wheel are discussed. C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP NASA, Lyndon B Johnson Space Ctr, 2101 NASA Pkwy,M-C ER3, Houston, TX 77058 USA. EM bluethmann@jsc.nasa.gov; ambrose@jsc.nasa.gov; diftler@jsc.nasa.gov; ehuber@roboteyes.com; fagg@cs.umass.edu; mtr@cs.umass.edu; rplatt@cs.umass.edu; grupen@cs.umass.edu; cynthiah@medit.mit.edu; zoz@medit.mit.edu; alockerd@medit.mit.edu; alan.peters@vanderbilt.edu; cjenkins@cs.usc.edu; mataric@cs.usc.edu; magda@aic.nrl.navy.mil NR 24 TC 1 Z9 1 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 2164-0572 BN 0-7803-8863-1 J9 IEEE-RAS INT C HUMAN PY 2004 BP 402 EP 421 PG 20 WC Robotics SC Robotics GA BCB10 UT WOS:000228484200024 ER PT S AU Whitson, P Bergh, K Maender, C Pietrzyk, R Jones, J Sams, C AF Whitson, P Bergh, K Maender, C Pietrzyk, R Jones, J Sams, C GP ieee TI Renal stone risk during spaceflight: Assessment and countermeasure validation SO 2004 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-6 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 06-13, 2004 CL Big Sky, MT SP Aerosp & Elect Syst Soc, IEEE ID CRYSTAL-GROWTH; KIDNEY-STONES; HUMAN-URINE; OXALATE; CALCIUM; NEPHROLITHIASIS; PATHOGENESIS AB Potassium citrate, a proven Earth-based therapy to minimize calcium-containing renal stone development, is being tested in a double-blind study as a countermeasure to reduce the risk of renal stone formation in crewmembers on the International Space Station. Subjects ingest two potassium citrate or placebo pills with the last meal of the day from L-3 (days prior launch) to R+14 (days after landing). Food, fluid, exercise, and medications are monitored for 48 hours (24 hours prior to and during the 24-hour urine collection period) to assess environmental influences other than microgravity. C1 Lyndon B Johnson Space Ctr, Houston, TX USA. RP Whitson, P (reprint author), Lyndon B Johnson Space Ctr, Houston, TX USA. NR 24 TC 0 Z9 0 U1 1 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-8155-6 J9 AEROSP CONF PROC PY 2004 BP 29 EP 34 DI 10.1109/AERO.2004.1367587 PG 6 WC Engineering, Aerospace SC Engineering GA BBF75 UT WOS:000225274000003 ER PT S AU Durham, HJ AF Durham, HJ GP ieee TI ISS program infrastructure upgrades to enhance science return: Current, planned & potential SO 2004 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-6 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 06-13, 2004 CL Big Sky, MT SP Aerosp & Elect Syst Soc, IEEE AB The command and communications architecture implemented by the International Space Station (ISS) Program (ISSP) determines the amount of data that can be transmitted to (i.e., "uplinked") and received from (i.e., "downlinked") the ISS vehicle. The current system design reflects cost reductions imposed over the last 13 years, and constrains data flows to much lower rates than are technologically feasible. These constraints will result in loss of irreplaceable opportunities for exploiting the science that could be returned from experiments conducted in the microgravity environment of the ISS. NASA has embarked on a series of projects to upgrade the end-to-end ISS Program communications architecture. This paper summarizes the content and schedule of projects currently underway and planned, as well as future potential efforts which still are in concept definition. The objective is to provide a high-level summary of prospective improvements in ISS science Support as an aid to designing ISS experiment hardware, software and procedures to take maximum advantage of those improvements.(12). C1 Lyndon B Johnson Space Ctr, United Space Alliance Program Integrat, ISS Payloads Off, Houston, TX 77058 USA. RP Durham, HJ (reprint author), Lyndon B Johnson Space Ctr, United Space Alliance Program Integrat, ISS Payloads Off, Houston, TX 77058 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-8155-6 J9 AEROSP CONF PROC PY 2004 BP 47 EP 58 DI 10.1109/AERO.2004.1367589 PG 12 WC Engineering, Aerospace SC Engineering GA BBF75 UT WOS:000225274000005 ER PT S AU Cervantes, D Montanez, L Tatge, L AF Cervantes, D Montanez, L Tatge, L GP ieee TI Low cost test bed tool development for validation of mission critical events SO 2004 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-6 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 06-13, 2004 CL Big Sky, MT SP Aerosp & Elect Syst Soc, IEEE AB The Cassini Program is one of the last large interplanetary spacecraft missions. It is a joint effort between the European Space Agency, the Italian Space Agency and NASA. The U.S. portion of the mission is managed for NASA by the Jet Propulsion Laboratory (JPL). The primary mission is to survey the complex Saturnian system and release the ESA-Huygens probe at Titan. The success of the Cassini Mission has been largely due to its many simulation test beds and its rigorous test program. The Integrated Test Laboratory (ITL) at the JPL is an integral part of the Cassini Program and provides "hardware in the loop simulation". Pre-launch, the ITL's primary role was to validate system level architecture, subsystem flight software, ground software, and support equipment simulation software. Its present role has increasingly focused on Mission Operations Sequence testing, anomaly investigation, training and validation of mission milestones. This expanded role has led to the development of necessary analysis tools. These tools were developed quickly and at low cost given that their necessity was not foreseen during early mission planning. Several rapid development techniques and cost cutting methods were used to implement the needed tools. The methods involved were; use of freeware, use of Commercial Off The Self (COTS) software, and technology transfer with other Projects at JPL. The use of freeware was an invaluable factor in the development of these tools. Freeware availability, reliability and support sped up the development cycle and subsequently cut costs. The widespread use of freeware in industry and by developers has led to mature and proven freeware. Code, concepts and help also tend to be readily available among developers at JPL and on the Internet. The freeware code used in the development of these tools included compilers, data base engines, user interfaces, and interpreters. COTS packages were used to aid rapid development. Their use was limited to specific tasks that would have required a long time to develop independently. Experience revealed that the COTS costs were offset by the shortened development cycle. COTS packages also offered the advantage of being multi-platform and could typically export into other formats. User familiarity with the COTS (Commercial Off The Shelf) packages used also decreased required training. Technology transfer with other Projects at JPL was another technique used to shorten the development cycle and subsequent costs. The transfer involved inheritance of software and limited use of its associated expertise to aid in development. Improvements were made to the inherited software and the new tools were designed to make it possible for other projects to use them with simple modifications. Two examples of this rapid development process are examined in detail in this paper: A pointing tool to verify performance of the Attitude and Articulation Control Subsystem during simulation runs of the Probe Relay Sequence, and a data gap analysis tool to quantify possible data losses that could occur during non-nominal Probe Mission scenarios. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Cervantes, D (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 7 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-8155-6 J9 AEROSP CONF PROC PY 2004 BP 59 EP 67 DI 10.1109/AERO.2004.1367590 PG 9 WC Engineering, Aerospace SC Engineering GA BBF75 UT WOS:000225274000006 ER PT S AU White, AL AF White, AL GP ieee TI Transient faults and network reliability SO 2004 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-6 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 06-13, 2004 CL Big Sky, MT SP Aerosp & Elect Syst Soc, IEEE AB This paper develops a method for the quantitative analysis of network reliability in the presence of both permanent and transient faults. Even though transient noise is considered a common occurrence in networks, a survey of the literature reveals an emphasis on permanent faults. Transient faults introduce a time element into the analysis of network reliability. With permanent faults it is sufficient to consider the faults that have accumulated by the end of the operating period. With transient faults the arrival and recovery time must be included. The number and location of faults in the system is a dynamic variable. Transient faults also introduce system recovery into the analysis. C1 NASA Langley, Hampton, VA 23681 USA. RP White, AL (reprint author), NASA Langley, MS 130, Hampton, VA 23681 USA. NR 3 TC 1 Z9 1 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-8155-6 J9 AEROSP CONF PROC PY 2004 BP 78 EP 83 DI 10.1109/AERO.2004.1367592 PG 6 WC Engineering, Aerospace SC Engineering GA BBF75 UT WOS:000225274000008 ER PT S AU Anselm, B AF Anselm, B GP ieee TI Lessons-learned on NASA's EOS/ICESat mission SO 2004 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-6 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 06-13, 2004 CL Big Sky, MT SP Aerosp & Elect Syst Soc, IEEE AB NASA's Earth Observing System (EOS) lee, Cloud, and Land Elevation Satellite (ICESat) mission was one of the first missions under Goddard Space Flight Center's (then-) new Rapid Spacecraft Development Office. This paper explores the lessons-learned under the ICESat successful implementation and launch, focusing on four areas: Procurement, Management, Technical, and Launch and Early Operations. Each of these areas is explored in a practical perspective of communication, the viewpoint of the players, and the interactions among the organizations. Conclusions and lessons-learned are summarized in the final section. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Anselm, B (reprint author), NASA, Goddard Space Flight Ctr, Code 429, Greenbelt, MD 20771 USA. NR 1 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-8155-6 J9 AEROSP CONF PROC PY 2004 BP 98 EP 104 DI 10.1109/AERO.2004.1367594 PG 7 WC Engineering, Aerospace SC Engineering GA BBF75 UT WOS:000225274000010 ER PT S AU Gal-Edd, J Fatig, CC AF Gal-Edd, J Fatig, CC GP ieee TI L2 - James Webb space telescope operationally friendly environment? SO 2004 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-6 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 06-13, 2004 CL Big Sky, MT SP Aerosp & Elect Syst Soc, IEEE AB One of the key components for James Webb Space Telescope (JWST) to meet its science goals is the Second Lagrange point (L2) environment. This,operationally friendly' environment provides JWST a dark, cold, and stable orbit to view the first starlight of the universe. The environment assists the science instruments with passive cooling, limited stray light, and large contact times with earth to increase the efficiency of the JWST. Now that JWST is moving into the design/construction phase, we are finding that the initial concepts now require a more detailed examination. We are finding that L2 has some issues that impact cost and operational friendliness. This paper will address some of these L2 environment challenges currently being reviewed: Cosmic Ray Environment Communications Orbit Maintenance and Determination To address the above L2 environment concerns, the JWST spacecraft and science planning system requires adjustment to the onboard 'event driven'. planning. As the spacecraft buildup continues, the challenges of communicating from L2 will be met so that JWST will see the first starlight in the universe. The communication items will be covered in other papers during this conference. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Gal-Edd, J (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 3 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-8155-6 J9 AEROSP CONF PROC PY 2004 BP 105 EP 110 DI 10.1109/AERO.2004.1367595 PG 6 WC Engineering, Aerospace SC Engineering GA BBF75 UT WOS:000225274000011 ER PT S AU Muirhead, BK AF Muirhead, BK GP ieee TI Mars rovers, past and future SO 2004 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-6 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 06-13, 2004 CL Big Sky, MT SP Aerosp & Elect Syst Soc, IEEE AB This paper(123) discusses the history of planetary rovers, including research vehicles, from the initial concepts in the early 1960's to the present. General characteristics and their evolution are discussed including mission drivers, technology limitations, controls approach, mobility and overall performance. Special emphasis is given to the next generation mission of rovers, the Mars Science Laboratory rover. This vehicle is being designed for a 2009 launch with the capability to operate over 80% of the surface of Mars for a full Martian year (687 days). It is designed to visit numerous sites, with a science payload capable of making measurements that will enable understanding the past or present habitability of Mars. C1 CALTECH, Jet Prop Lab, Mars Sci Lab, Pasadena, CA 91125 USA. RP Muirhead, BK (reprint author), CALTECH, Jet Prop Lab, Mars Sci Lab, Pasadena, CA 91125 USA. NR 0 TC 1 Z9 1 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-8155-6 J9 AEROSP CONF PROC PY 2004 BP 128 EP 134 DI 10.1109/AERO.2004.1367598 PG 7 WC Engineering, Aerospace SC Engineering GA BBF75 UT WOS:000225274000014 ER PT S AU Johnston, MD Graf, JE Zurek, RW Eisen, HJ Jai, BH AF Johnston, MD Graf, JE Zurek, RW Eisen, HJ Jai, BH GP ieee TI The mars reconnaissance orbiter mission SO 2004 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-6 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 06-13, 2004 CL Big Sky, MT SP Aerosp & Elect Syst Soc, IEEE AB The Mars Reconnaissance Orbiter (MRO) will be launched in August 2005 by an Atlas V 401 expendable launch vehicle from Cape Canaveral Air Force Station, USA. It will deliver to Mars orbit a payload to conduct remote sensing science observations, identify and characterize sites for future landers, and provide critical telecom/navigation relay capability for follow-on missions. The mission is designed to provide global, regional survey, and targeted observations from a low 255km by 320km Mars orbit with a 3:00 P.M. local mean solar time (ascending node). During the one Martian year (687 Earth days) primary science phase, the orbiter will acquire visual and near-infrared high-resolution images of the planet's surface, monitor atmospheric weather and climate, and search the upper crust for evidence of water. After this science phase is completed, the orbiter will provide telecommunications support for spacecraft launched to Mars in the 2007 and 2009 opportunities. The primary mission ends on December 3 1, 20 10, approximately 5.5 years after launch. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Johnston, MD (reprint author), CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. NR 1 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-8155-6 J9 AEROSP CONF PROC PY 2004 BP 135 EP 150 DI 10.1109/AERO.2004.1367599 PG 16 WC Engineering, Aerospace SC Engineering GA BBF75 UT WOS:000225274000015 ER PT S AU Castano, R Judd, M Estlin, T Anderson, RC Scharenbroich, L Song, L Gaines, D Fisher, F Mazzoni, D Castano, A AF Castano, R Judd, M Estlin, T Anderson, RC Scharenbroich, L Song, L Gaines, D Fisher, F Mazzoni, D Castano, A GP ieee TI Autonomous onboard traverse science system SO 2004 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-6 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 06-13, 2004 CL Big Sky, MT SP Aerosp & Elect Syst Soc, IEEE AB The Onboard Autonomous Science Investigation System (OASIS) is a technology for increasing science return during rover traverses by prioritizing data onboard, and identifying and reacting to unanticipated science opportunities. Rovers of the future will have the capacity to collect more data than can be downlinked back to Earth. OASIS can increase mission science return by carefully selecting the data with the highest science interest for downlink. These rovers may also be required to traverse long distances with little to no interaction with the science team on Earth. OASIS can act as a geologist's assistant and can autonomously direct the rover to take additional measurements of "interesting" rocks. The importance of characterizing the terrain along these traverses, a Study that is now becoming known as traverse science, increases with the distances the rover must travel. This paper provides a brief overview of the entire OASIS system and how it analyzes one type of data - grayscale images taken by the rover for engineering and hazard avoidance purposes. Although the OASIS system can apply the same type of analysis to different data types, such as color images, hyperspectral images or point spectrometer data, we will only focus on grayscale images here. The paper also describes the latest advances in two key aspects of the system: image prioritization and the science alert. In image prioritization, we combine the results from three distinct prioritization methods to arrive at an overall downlink ranking of the images collected during a traverse. The science alert is a capability that enables the rover to identify and react to a pre-specified, and scientifically significant, signature. Once this signature has been detected via the onboard science analysis component, the planning and scheduling module updates the rover command sequence to stop the traverse and signal Earth of the find. If there is sufficient time and onboard resources before the next downlink opportunity, additional data samples of the target may be autonomously collected. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Castano, A (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 11 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-8155-6 J9 AEROSP CONF PROC PY 2004 BP 159 EP 167 DI 10.1109/AERO.2004.1367601 PG 9 WC Engineering, Aerospace SC Engineering GA BBF75 UT WOS:000225274000017 ER PT S AU Mandl, D AF Mandl, D GP ieee TI Experimenting with sensor webs using earth observing 1 SO 2004 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-6 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 06-13, 2004 CL Big Sky, MT SP Aerosp & Elect Syst Soc, IEEE DE sensor webs; satellite constellations; progressive mission autonomy; EO-1; Hyperion; ALI AB The New Millennium Program (NMP) Earth Observing I (EO-I) satellite was launched November 21, 2000 as a one year technology validation mission. After an almost flawless first year of operations, EO-I continued to operate in a test bed mode to validate additional technologies and concepts that will be applicable to future sensor webs. A sensor web is a group of sensors, whether space-based, ground-based or airplane-based which act in a collaborative autonomous manner to produce more value than would otherwise result from the individual observations. Interestingly, it seems that the trend at this time is to link a set of heterogeneous satellites and instruments together in an "ad hoc" constellation for a limited period of time to get new science products. In our experiments, we used the MODIS instruments on Aqua and Terra to locate terrestrial events such as forest fires and then to trigger high-resolution images of targeted events with either the Advance Land Imager (ALI) or Hyperion on EO-1. To achieve this, we created a variety of software on the spacecraft and on the ground to coordinate the planning and triggering of these images. Furthermore, it became clear from the lessons learned that future sensor webs are going to need some key capabilities to enable progressive autonomy and sufficient reuse to make these constellation cost effective for science. This paper describes the experiments, the lessons learned and the implications for future sensor webs. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Mandl, D (reprint author), NASA, Goddard Space Flight Ctr, Code 584, Greenbelt, MD 20771 USA. NR 4 TC 2 Z9 3 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-8155-6 J9 AEROSP CONF PROC PY 2004 BP 176 EP 183 DI 10.1109/AERO.2004.1367603 PG 8 WC Engineering, Aerospace SC Engineering GA BBF75 UT WOS:000225274000019 ER PT S AU Sherwood, R Chien, S Tran, D Cichy, B Castano, R Davies, A Rabideau, G AF Sherwood, R Chien, S Tran, D Cichy, B Castano, R Davies, A Rabideau, G GP ieee TI Preliminary results of the autonomous sciencecraft experiment SO 2004 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-6 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 06-13, 2004 CL Big Sky, MT SP Aerosp & Elect Syst Soc, IEEE AB The Autonomous Sciencecraft Experiment (ASE) will operate onboard the Earth Orbiter 1 mission in 2004. The ASE software uses onboard continuous planning, robust task and goal-based execution, and onboard machine learning and pattern recognition to radically increase science return by enabling intelligent downlink selection and autonomous retargeting. In this paper we discuss how these AI technologies are synergistically integrated in multi-layer control architecture to enable a virtual spacecraft science agent. We will also present the preliminary results from flight validation of this experiment. This software will demonstrate the potential for space missions to use onboard decision-making to detect, analyze, and respond to science events, and to downlink only the highest value science data. As a result, ground-based mission planning and analysis functions will be simplified, thus reducing operations cost.(1). C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Sherwood, R (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 13 TC 0 Z9 0 U1 0 U2 3 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-8155-6 J9 AEROSP CONF PROC PY 2004 BP 184 EP 192 DI 10.1109/AERO.2004.1367604 PG 9 WC Engineering, Aerospace SC Engineering GA BBF75 UT WOS:000225274000020 ER PT S AU Carlisle, CC Finnegan, EJ AF Carlisle, CC Finnegan, EJ GP ieee TI Space Technology 5: Pathfinder for future micro-sat constellations SO 2004 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-6 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 06-13, 2004 CL Big Sky, MT SP Aerosp & Elect Syst Soc, IEEE AB The Space Technology 5 Project, currently in the implementation phase, is part of the National Aeronautics and Space Administration's New Millennium Program. Space Technology 5 is a constellation of three microsatellites, with a target launch date of December 2005. A three-month flight demonstration phase is planned. Space Technology 5 addresses technology challenges for future micro-satellite missions, as well as test and operations strategies for multi-spacecraft missions. By validating the technologies, science capability and constellation concepts in flight, Space Technology 5 enables future missions to use these technologies and concepts at reduced risk. This paper describes the Space Technology 5 mission, and the applicability of the technologies, spacecraft, and mission concepts to future missions. It also discusses the validation approach for the Space Technology 5 mission in general. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Carlisle, CC (reprint author), NASA, Goddard Space Flight Ctr, Code 495, Greenbelt, MD 20771 USA. NR 5 TC 1 Z9 1 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-8155-6 J9 AEROSP CONF PROC PY 2004 BP 227 EP 239 DI 10.1109/AERO.2004.1367608 PG 13 WC Engineering, Aerospace SC Engineering GA BBF75 UT WOS:000225274000024 ER PT S AU Rossoni, P AF Rossoni, P GP ieee TI Design and verification of a mechanical system for magnetospheric mapping missions SO 2004 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-6 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 06-13, 2004 CL Big Sky, MT SP Aerosp & Elect Syst Soc, IEEE AB This paper describes the design and qualification of the Space Technology 5 spacecraft mechanical system. Key points include: Testing results for the "Frisbee" type Deployer system, which imparts a precise spin rate to the spacecraft; Layout of the structural bus, with emphasis on design for both compactness and accessibility during assembly; Design of the electronics housing, which serves an important dual purpose as the spacecraft structural backbone. Also included is a description of its special accommodations for electrical harness and the integration process; Electro-mechanical aspects of the separation connectors and shape-memory-actuated pin pullers; Unique challenges due to limited volume and resources were overcome through extensive testing and "skunkworks" type development procedures. Overall, this paper encompasses the unique mechanical system design innovations to enable the 25 kg, fully functional Space Technology 5 spacecraft to blaze a trail towards scale-reduction and system functional integration for upcoming nano-satellite constellations. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Rossoni, P (reprint author), NASA, Goddard Space Flight Ctr, Mail Code 546, Greenbelt, MD 20771 USA. NR 4 TC 1 Z9 1 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-8155-6 J9 AEROSP CONF PROC PY 2004 BP 240 EP 249 DI 10.1109/AERO.2004.1367609 PG 10 WC Engineering, Aerospace SC Engineering GA BBF75 UT WOS:000225274000025 ER PT S AU Buehler, MG Garrett, HB Wellman, J Moynihan, PI Some, RR Kuhlman, KR Brinza, DE AF Buehler, MG Garrett, HB Wellman, J Moynihan, PI Some, RR Kuhlman, KR Brinza, DE GP ieee TI NMP Space Environmental Monitor (SEM): Preliminary design concept SO 2004 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-6 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 06-13, 2004 CL Big Sky, MT SP Aerosp & Elect Syst Soc, IEEE AB The New Millennium Program is examining the possibility of developing a low-cost Space Environmental Monitor (SEM) for inclusion on its technology validation flights to monitor the space environment. The raison d'etre for this effort follows from the need to characterize the validation environment so that future users can extrapolate or scale NMP test results to their end-use environment. The short-term objective is to develop a "hockey-puck" size diagnostic package available from commercial sources. The environments of interest are contamination, atomic oxygen, ionizing radiation, cosmic radiation, EMI, and temperature. This paper describes the process by which sensors were chosen, discusses each sensor in detail, and describes a conceptual design that includes a microcontroller data logger with data storage and interfaces to the sensors and spacecraft. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Buehler, MG (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 14 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-8155-6 J9 AEROSP CONF PROC PY 2004 BP 250 EP 262 DI 10.1109/AERO.2004.1367610 PG 13 WC Engineering, Aerospace SC Engineering GA BBF75 UT WOS:000225274000026 ER PT S AU Some, RR Weisbin, C Neff, J Witz, J AF Some, RR Weisbin, C Neff, J Witz, J GP ieee TI XML based tools for assessing potential impact of advanced technology SO 2004 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-6 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 06-13, 2004 CL Big Sky, MT SP Aerosp & Elect Syst Soc, IEEE AB A hierarchical XML database and related analysis tools are being developed by the New Millennium Program to provide guidance on the relative impact, to future NASA missions, of advanced technologies under consideration for developmental funding. An XML dictionary codifies a standardized taxonomy and, in effect, begins to define a set of ontological relationships for space missions, systems, subsystems, and technologies. The use of an XML dictionary and the associated XML database are central to the concept behind the analysis tools. The XML dictionary, and the taxonomies defined therein, may be submitted to NASA as a proposed guideline. The analysis tools are planned for use across a broad range of NASA projects and technology planning activities. In addition, if successful, the products developed under this task may also be submitted for use by the DOD. This paper describes the motivation for the project, the technical approach, the reasoning behind the selection of XML based tools, the current state of the project, and future plans for this work. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Some, RR (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 9 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-8155-6 J9 AEROSP CONF PROC PY 2004 BP 282 EP 291 DI 10.1109/AERO.2004.1367612 PG 10 WC Engineering, Aerospace SC Engineering GA BBF75 UT WOS:000225274000028 ER PT S AU Some, RR Czikmantory, A Neff, J Marshall, M AF Some, RR Czikmantory, A Neff, J Marshall, M GP ieee TI XML hierarchical database for missions and technologies SO 2004 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-6 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 06-13, 2004 CL Big Sky, MT SP Aerosp & Elect Syst Soc, IEEE AB A hierarchical XML (eXtensible Markup Language) database is being developed by the New Millennium Program to assist in technology Return On Investment (ROI) analysis and technology portfolio optimization. The database contains mission requirements and technology capabilities, which are related by use of an XML dictionary. The XML dictionary codifies a standardized taxonomy and, in effect, begins defining a set of ontological relationships for space missions, systems, subsystems and technologies. The XML dictionary, and the taxonomies defined therein, will be submitted to NASA, DOD and commercial standardization bodies as a proposed standard. In addition to being used for ROI analysis, the database is being examined for use in project planning, tracking and documenting. This paper describes the motivation for the database project, the technical approach, the reasoning behind the selection of an XML based approach, the current state of the project, and future plans for this work. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Some, RR (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 7 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-8155-6 J9 AEROSP CONF PROC PY 2004 BP 292 EP 303 DI 10.1109/AERO.2004.1367613 PG 12 WC Engineering, Aerospace SC Engineering GA BBF75 UT WOS:000225274000029 ER PT S AU Bergstrom, SL Rummel, JD AF Bergstrom, SL Rummel, JD GP ieee TI Planetary protection considerations for future exploration SO 2004 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-6 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 06-13, 2004 CL Big Sky, MT SP Aerosp & Elect Syst Soc, IEEE AB Since 1963, an international consensus policy has been in place to control contamination of planets by both terrestrial organisms and organic constituents. The policy, maintained by the Committee on Space Research of the International Council for Science (ICSU, originally the International Council of Scientific Unions) and reflected in a policy of the National Aeronautics and Space Administration, lays out a framework of guidelines for implementing missions while avoiding mission-caused microbial contamination. During the course of structuring today's active program to explore our solar system, especially in the face of a focus on astrobiology and the search for life, it has become increasingly apparent that planetary protection factors will have a significant impact on future mission design, cost, and complexity. For some missions, the microbial load on the hardware must be limited during manufacturing and building processes, and controlled during assembly, test and launch operations. These limitations can be assured by adopting strict clean room standards, including personnel and operational procedures, re-cleaning with appropriate fluids to maintain cleanliness during pre-launch processing of hardware, and the possible necessity to employ a terminal sterilization process. For these and other missions, it is also necessary to examine the hazards of accidental impacts and other events that may cause the release of organisms in environments where they may grow and thrive. Therefore, various constraints on flight trajectories, orbital altitudes, and dwell times must be considered and implemented during the design phase of such missions. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Bergstrom, SL (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 12 TC 0 Z9 0 U1 0 U2 2 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-8155-6 J9 AEROSP CONF PROC PY 2004 BP 343 EP 350 DI 10.1109/AERO.2004.1367618 PG 8 WC Engineering, Aerospace SC Engineering GA BBF75 UT WOS:000225274000034 ER PT S AU Kuhlman, GM Keymeulen, D Buehler, MG Kounaves, SP AF Kuhlman, GM Keymeulen, D Buehler, MG Kounaves, SP GP ieee TI Detecting heavy metals in solution using Electronic-Tongue 3 REDOX water quality sensors SO 2004 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-6 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 06-13, 2004 CL Big Sky, MT SP Aerosp & Elect Syst Soc, IEEE AB This paper describes results obtained from the E-Tongue 3 apparatus used to characterize residual contaminates in water. This apparatus is intended for use in water quality measurements for the ISS (International Space Station). The apparatus contains nine planar electrochemical cells and a conductivity sensor. Detection of contaminate ions in solution uses ASV (Anodic Stripping Voltammetry) with a detection limit in the 10 muM range. A linear calibration curve was achieved using Zn Pb, Cu, and Mn cations. A robust method for identifying electroactive species is presented and uses the Savitzky-Golay second derivative method. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Kuhlman, GM (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. RI Bueno, Ligia/P-1359-2014; OI Kounaves, Samuel/0000-0002-2629-4831 NR 10 TC 2 Z9 2 U1 1 U2 2 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-8155-6 J9 AEROSP CONF PROC PY 2004 BP 363 EP 378 DI 10.1109/AERO.2004.1367620 PG 16 WC Engineering, Aerospace SC Engineering GA BBF75 UT WOS:000225274000036 ER PT S AU Quadrelli, MB Chang, J Mettler, E Zimmermann, W Chau, S Sengupta, A AF Quadrelli, MB Chang, J Mettler, E Zimmermann, W Chau, S Sengupta, A GP ieee TI System architecture for guided herd of robots exploring titan SO 2004 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-6 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 06-13, 2004 CL Big Sky, MT SP Aerosp & Elect Syst Soc, IEEE AB This paper describes a system architecture for an aerobot blimp guiding and controlling a herd of sondes on Titan's surface. Options for inertial navigation are proposed that make use of a direct communication link to Earth. A potential field controller is used for autonomous tracking of terrain features on the surface, and hazard avoidance. The result of distributed simulation studies demonstrate that the method used for control is feasible even if significant uncertainty exists in the dynamics and environmental models. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Quadrelli, MB (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 6 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-8155-6 J9 AEROSP CONF PROC PY 2004 BP 379 EP 387 DI 10.1109/AERO.2004.1367621 PG 9 WC Engineering, Aerospace SC Engineering GA BBF75 UT WOS:000225274000037 ER PT S AU Behar, A Matthews, J Carsey, F Jones, J AF Behar, A Matthews, J Carsey, F Jones, J GP ieee TI NASA/JPL Tumbleweed Polar Rover SO 2004 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-6 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 06-13, 2004 CL Big Sky, MT SP Aerosp & Elect Syst Soc, IEEE AB The Tumbleweed Rover, currently under development at the Jet Propulsion Laboratory (JPL) in Pasadena, California, is a large, windblown, inflated ball, which carries an instrument payload in its interior. Such rovers offer an effective and simple means of gathering data over large spatial extents of Earth, Mars, and other solar system bodies. Tumbleweeds could prove to be a safe and economical way of deploying instruments such as a ground penetrating radar or a magnetometer in numerous hostile environments. The latest version of the rover was recently deployed in Greenland, where it completed a more than 130km autonomous traverse across an ice sheet. Communicating via the Iridium satellite network, the rover in question successfully and reliably relayed live GPS, temperature, and pressure data to a ground station at JPL for nearly ten days. The follow-on rover is currently being readied for a traverse from the South Pole to the coast of Antarctica some 2000km away. The Antarctic test is set to take place in February of 2004 and will serve to verify Tumbleweed as an effective means of harvesting data in extreme and remote settings. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Behar, A (reprint author), CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. NR 5 TC 1 Z9 1 U1 1 U2 3 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-8155-6 J9 AEROSP CONF PROC PY 2004 BP 388 EP 395 DI 10.1109/AERO.2004.1367622 PG 8 WC Engineering, Aerospace SC Engineering GA BBF75 UT WOS:000225274000038 ER PT S AU Franklin, SF Slonski, JP Kerridge, S Noreen, G Townes, S Schwartzbaum, E Synnott, S Deutsch, M Edwards, C Devereaux, A Austin, R Edwards, B Scozzafava, JJ Boroson, DM Roberts, WT Biswas, A Pillsbury, AD Khatri, FI Sharma, J Komarek, T AF Franklin, SF Slonski, JP Kerridge, S Noreen, G Townes, S Schwartzbaum, E Synnott, S Deutsch, M Edwards, C Devereaux, A Austin, R Edwards, B Scozzafava, JJ Boroson, DM Roberts, WT Biswas, A Pillsbury, AD Khatri, FI Sharma, J Komarek, T GP ieee TI The 2009 Mars Telecom Orbiter mission SO 2004 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-6 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 06-13, 2004 CL Big Sky, MT SP Aerosp & Elect Syst Soc, IEEE AB This paper provides a comprehensive overview of the proposed Mars Telecom Orbiter (MTO) mission. Launched in 2009, MTO would provide Mars-to-Earth relay services for NASA missions arriving at Mars between 2010 and 2020, enabling far higher science data return and lowering the cost for these missions. MTO also carries an optical communications payload, which will demonstrate downlink bit rates from 1 Mbps up to and possible exceeding 30 Mbps. MTO will also search for the potential Mars Sample Return orbiting sample, and will demonstrate this capability beforehand, using the sample canister, which it carries. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Franklin, SF (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 5 TC 1 Z9 1 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-8155-6 J9 AEROSP CONF PROC PY 2004 BP 437 EP 456 DI 10.1109/AERO.2004.1367627 PG 20 WC Engineering, Aerospace SC Engineering GA BBF75 UT WOS:000225274000042 ER PT S AU Mattingly, R Matousek, S Jordan, F AF Mattingly, R Matousek, S Jordan, F GP ieee TI Continuing evolution of Mars sample return SO 2004 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-6 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 06-13, 2004 CL Big Sky, MT SP Aerosp & Elect Syst Soc, IEEE AB In 2001, JPL commissioned four industry teams to make a fresh examination of Mars Sample Return (MSR) mission architectures. As new fiscal realities of a cost-capped Mars Exploration Program unfolded, it was evident that the converued-upon MSR concept did not fit reasonably within a balanced program. Therefore, alone, with a new MSR Science Steering Group, JPL asked the industry teams plus JPL's Team-X to explore ways to reduce the cost. A paper presented at last year's conference described the emergence of a new, affordable "Groundbreaking-MSR" concept [1]. This paper addresses the continued evolution of the Groundbreaking MSR concept over the last year. One of the tenets of the low-cost approach is to use substantial heritage from an earlier mission, Mars Science Laboratory (MSL). Recently, the MSL project developed and switched its baseline to a revolutionary landing approach, coined "skycrane" where the MSL, which is a rover, would be lowered gently to the Martian surface from a hovering C, vehicle. MSR has adopted this approach in its mission studies, again continuing to capitalize on the heritage for a significant portion of the new lander. In parallel, a MSR Technology Board was formed to reexamine MSR technology needs and participate in a continuing refinement of architectural trades. While the focused technology program continues to be definitized through the remainder of this year, the current assessment of what technology development is required, is discussed in this paper. In addition, the results of new trade studies and considerations will be discussed. Adopting these changes, the Groundbreaking MSR concept C, has shifted to that presented in this paper. It remains a project that is affordable and meets the basic science needs defined by the MSR Science Steering Group in 2002. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Mattingly, R (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 9 TC 1 Z9 1 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-8155-6 J9 AEROSP CONF PROC PY 2004 BP 477 EP 492 DI 10.1109/AERO.2004.1367630 PG 16 WC Engineering, Aerospace SC Engineering GA BBF75 UT WOS:000225274000045 ER PT S AU Perera, J Holsomback, J AF Perera, J Holsomback, J GP ieee TI Use of probabilistic risk assessments for the International Space Station Program SO 2004 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-6 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 06-13, 2004 CL Big Sky, MT SP Aerosp & Elect Syst Soc, IEEE AB The purpose of risk management is to identify what can go wrong, how likely it is for these to occur, and what are the consequences if they were to occur. The International Space Station (ISS) Program office uses a continuous risk management process in identifying, analyzing, planning, tracking, controlling and communicating risks. This strategy manages risk by (i) embedding risk management processes into normal day-today activities to identify and help manage any risks or potential threats, (ii) facilitating risk-management processes and analyses by providing analytical support and tools. One of the key quantitative risk analysis methods employed by the ISS program is the Probabilistic Risk Assessment (PRA) modeling techniques. PRA is a comprehensive structured and logical analysis method for identifying an assessing risks in complex technological systems for the purpose of cost-effectively improving their safety and performance. The International Space Station has been modeled using this PRA methodology and is now used extensively by program management to make strategic decisions. The PRA results can be used as a powerful decision-making tool in support of design, operations, and prioritizing upgrade or reconfiguration decisions. The process helps identify potential new risks, analyze existing risks and subsequently can weigh different options available to the Program to mitigate those risks. The ISS PRA captures possible accident scenarios that lead to several undesired consequences called End States. Some background into the PRA methodology including examples of trade studies recently conducted for the ISS Program will be highlighted in this paper. C1 NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. RP Perera, J (reprint author), NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA. NR 3 TC 0 Z9 0 U1 1 U2 2 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-8155-6 J9 AEROSP CONF PROC PY 2004 BP 512 EP 517 DI 10.1109/AERO.2004.1367633 PG 6 WC Engineering, Aerospace SC Engineering GA BBF75 UT WOS:000225274000048 ER PT S AU Lo, MW AF Lo, MW GP ieee TI The coverage of elliptical orbits using ergodic theory SO 2004 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-6 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 06-13, 2004 CL Big Sky, MT SP Aerosp & Elect Syst Soc, IEEE AB One of the key performance metrics for satellite constellations is the statistics of the visibility periods between the satellites and points on the ground. Associated with this are other desirable communications statistics such as data through-put, link qualities, etc. Typically, the computation of coverage statistics requires the propagation of the trajectories. For orbits with non-repeating ground tracks, this may require orbit propagation for tens of years per spacecraft. Lo [1] proposed an approach using ergodic theory which replaced the need to compute the statistics from integrated trajectories by a definite integral over the circular region of the elevation mask of a point on the ground. The effects of J(2) due to the non-spherical shape of the Earth are included in the definite integral. The definite integral can be implemented in Excel for quick trade studies. But the simple geometric methods used to derive the integral for circular orbits cannot be readily extended to elliptical orbits. In this paper a new algorithm using differential geometry enables us to extend this theory to elliptical orbits. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Lo, MW (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 301-140L, Pasadena, CA 91109 USA. NR 7 TC 2 Z9 2 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-8155-6 J9 AEROSP CONF PROC PY 2004 BP 541 EP 546 DI 10.1109/AERO.2004.1367638 PG 6 WC Engineering, Aerospace SC Engineering GA BBF75 UT WOS:000225274000052 ER PT S AU Regehr, MW Acikmese, AB Ahmed, A Aung, MM Bailey, R Bushnell, C Clark, KC Hicke, A Lytle, B MacNeal, P Rasmussen, RE Shields, J Singh, G AF Regehr, MW Acikmese, AB Ahmed, A Aung, MM Bailey, R Bushnell, C Clark, KC Hicke, A Lytle, B MacNeal, P Rasmussen, RE Shields, J Singh, G GP ieee TI The formation control testbed SO 2004 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-6 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 06-13, 2004 CL Big Sky, MT SP Aerosp & Elect Syst Soc, IEEE AB Terestrial Planet Finder (TPF) is a space telescope mission which will perform spectral analysis of the infrared emissions from extrasolar planets, and which will search for carbon-based life on such planets. One configuration being considered for this mission is a stellar interferometer with several collectors and a combiner on separate spacecraft flying in a tightly controlled formation. The distance to earth for this mission will be sufficiently great that having ground in the loop for reconfiguration or collision avoidance maneuvers will be impractical. Moreover, because of constraints in the orientation of the spacecraft relative to the sun, limitations on the field of view of relative range and bearing sensors, and restrictions on the orientations of thrusters, both the attitude and the relative position of each spacecraft in the formation must be taken into account in the event of a temporary sensing or control fault during maneuvers. These maneuvers include initial deployment of the formation, reconfiguration, and collision avoidance maneuvers. The Formation Algorithms and Simulation Testbed (FAST) and the Formation Control Testbed (FCT) at JPL are being built to simulate and demonstrate 6 degree of freedom, autonomous formation flying and reconfiguration for TPF. The testbeds are complementary. Control algorithms simulated in the FAST will be tested in the FCT in order to validate the FAST. This paper describes the design and construction of the Formation Control Testbed. The FCT consists of three robots navigating on an air bearing floor, propelled by cold gas thrusters. Each robot contains an attitude platform supported on a spherical air bearing which provides three rotational degrees of freedom. The sixth degree of freedom, vertical translation, will be provided by a powered vertical stage, actively controlled to provide a simulated zero-g environment for the attitude platform. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Regehr, MW (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,M-S 171-113, Pasadena, CA 91109 USA. NR 6 TC 1 Z9 2 U1 0 U2 2 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-8155-6 J9 AEROSP CONF PROC PY 2004 BP 557 EP 564 DI 10.1109/AERO.2004.1367641 PG 8 WC Engineering, Aerospace SC Engineering GA BBF75 UT WOS:000225274000054 ER PT S AU Metzger, PT Lane, JE Youngquist, RC AF Metzger, PT Lane, JE Youngquist, RC GP ieee TI Asymmetric electrostatic radiation shielding for spacecraft SO 2004 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-6 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 06-13, 2004 CL Big Sky, MT SP Aerosp & Elect Syst Soc, IEEE ID ENERGETIC PARTICLES; VEHICLES; ACE AB The physics of the radiation shielding problem possess several asymmetries which may be exploited in electrostatics to obtain nearly isotropic protection without radial symmetry in the fields, a concept that has been overlooked in previous studies. Electrostatic shielding is advantageous because it solves the problem of secondary radiation generated in passive shields and allows passive shields to be smaller and more directional. This paper presents the results of computer simulations for a linear quadrupole configuration to demonstrate shielding effectiveness for protons and high-Z, high-energy particles, while at the same time driving away thermal electrons. The study indicates that this shielding method is nearly feasible with existing technology, and only modest gains may be needed to make it a reality. C1 NASA, John F Kennedy Space Ctr, KSC Appl Phys Lab, Kennedy Space Ctr, FL 32899 USA. RP Metzger, PT (reprint author), NASA, John F Kennedy Space Ctr, KSC Appl Phys Lab, YA-C3-E, Kennedy Space Ctr, FL 32899 USA. OI Metzger, Philip/0000-0002-6871-5358 NR 25 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-8155-6 J9 AEROSP CONF PROC PY 2004 BP 626 EP 637 DI 10.1109/AERO.2004.1367649 PG 12 WC Engineering, Aerospace SC Engineering GA BBF75 UT WOS:000225274000062 ER PT S AU Caffrey, RT Udomkesmalee, G Hayati, SA AF Caffrey, RT Udomkesmalee, G Hayati, SA GP ieee TI Initiating the 2002 Mars Science Laboratory (MSL) focused technology program SO 2004 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-6 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 06-13, 2004 CL Big Sky, MT SP Aerosp & Elect Syst Soc, IEEE AB The Mars Science Laboratory (MSL) Project is an aggressive mission launching in 2009 to deliver a new generation of rover safely to the surface of Mars and conduct comprehensive in situ investigations using a new generation of instruments. This system will be designed to land with precision and be capable of operating over a large percentage on the surface of Mars. It will have capabilities that will support NASA's scientific goals into the next decade of exploration. The MSL Technology Program is developing a wide-range of technologies needed for this Mission and potentially other space missions. The MSL Technology Program reports to both the MSL Project and the Mars Technology Program (MTP). The dual reporting process creates a challenging management situation, but ensures the new technology meets both the specific MSL requirements and the broader Mars Program requirements. MTP is a NASA-wide technology development program managed by the Jet Propulsion Laboratory (JPL) and is divided into a Focused Program and a Base Program. The Focused Technology Program addresses technologies that are specific and critical to near-term missions, while the Base Technology Program addresses those technologies that are applicable to multiple missions and which can be characterized as longer term, higher risk, and high payoff technologies. The MSL Technology Program is under the Focused Program and is tightly coupled to MSL's mission milestones and deliverables. The technology budget is separate from the flight Project budget, but the technology's requirements and the development process are tightly coordinated with the Project. The Technology Program combines proven management techniques of flight projects with commercial and academic technology management strategies, to create a technology management program that meets the near-term requirements of MSL and the long-term requirements of MTP. This paper examines the initiation of 2002 MSL Technology program. Some of the areas discussed in this paper include technology definition, task selection, technology management, and technology assessment. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Caffrey, RT (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 7 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-8155-6 J9 AEROSP CONF PROC PY 2004 BP 638 EP 652 DI 10.1109/AERO.2004.1367650 PG 15 WC Engineering, Aerospace SC Engineering GA BBF75 UT WOS:000225274000063 ER PT S AU Shapiro, AA AF Shapiro, AA GP ieee TI Technology infusion for space-flight programs SO 2004 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-6 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 06-13, 2004 CL Big Sky, MT SP Aerosp & Elect Syst Soc, IEEE AB A tremendous amount of difficulty is encountered in moving technologies from laboratory demonstration (NASA Technology Readiness Level (TRL) 3) to prototype demonstration in a relevant environment (TRL 6). This ability to infuse technologies into NASA space flight programs is limited by a number of factors. Most research funding is for R&D activities that fund tasks from TRL1 to TRL3 (concept to laboratory demonstration). Most flight projects are only interested in technologies that are at TRL6 or higher with no incentive for projects to use any space-unproven technology unless it is essential to completion of the specific mission. Semiconductors have been following Moore's law for at least four decades, meaning that electronics and packaging technologies that are more than two years old are essentially obsolete. It takes about two years to space-qualify a technology if a particular mission regards it critical. There are few or no mechanisms to qualify technologies that are not considered critical to a particular mission. Additionally, it may take 5-8 years after qualification to launch. This means that nearly all electronics being used in spacecraft, with the exception of a few specialty components such as sensors like the Herschel/Planck bolometers, are many generations obsolete. The same can be said for packaging. A new approach could be used to reduce the risk of using modem technologies and facilitate their timely implementation. One approach is to: coordinate all TRL1-3 R&D funding (reduce overlap); require clear and precise statements of work, require progress milestones (i.e. run an experiment, complete literature survey) and to perform independent risk assessments on all TRL1-3 projects using a variety of tools. The tools could be used to rate the technologies in three categories: looks promising - continue work; ready for TRL4 and move it into an implementation phase; or, is unlikely to be useable in the next n years - discontinue funding (long-term research would fall in the first category). The residual funding from the RD SIB) projects to one of more "smaller" (< $600M) cost-and-time-constrained projects. Of course, science results of the highest caliber are the basis of all agreements. In other words, cheaper, faster, better are still fundamental... to wit, quality, schedule and budget. The challenge for modem PM's is clear. To maximize the likelihood of success, the PM needs a strong buffer of margin and reserves. However, having a buffer does not necessarily translate into understanding whether it is enough, or how and when to release/spend reserves. Thus, a PM needs a well-developed reserves management plan, a.k.a. cash flow planned inside the time boundaries to defeat threats. A technique is offered to plan for cash flow of reserves that can pay great dividends in confidence and eventual success. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Atkins, KL (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 3 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-8155-6 J9 AEROSP CONF PROC PY 2004 BP 3942 EP 3955 PG 14 WC Engineering, Aerospace SC Engineering GA BBF75 UT WOS:000225274000399 ER PT S AU Kordon, M Klimeck, G Hanks, D Hua, H AF Kordon, M Klimeck, G Hanks, D Hua, H GP ieee TI Evolutionary computing for spacecraft power subsystem design search and optimization SO 2004 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-6 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 06-13, 2004 CL Big Sky, MT SP Aerosp & Elect Syst Soc, IEEE AB Evolutionary computing has proven to be a straightforward and robust approach for optimizing a wide range of difficult analysis and design problems. This paper discusses the application of these techniques to an existing space vehicle power subsystem resource and performance simulation in a parallel processing environment. Using this method, engineers can trade off subsystem goals of mass, cost and performance then automatically size power elements based on their anticipated performance. Our results show that this approach has the potential to improve the space system trade study process. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91001 USA. RP Kordon, M (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91001 USA. RI Klimeck, Gerhard/A-1414-2012 OI Klimeck, Gerhard/0000-0001-7128-773X NR 9 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-8155-6 J9 AEROSP CONF PROC PY 2004 BP 4004 EP 4014 PG 11 WC Engineering, Aerospace SC Engineering GA BBF75 UT WOS:000225274000406 ER PT S AU Lee, M Weidner, RJ AF Lee, M Weidner, RJ GP ieee TI Virtual Mission Operation Framework SO 2004 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-6 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 06-13, 2004 CL Big Sky, MT SP Aerosp & Elect Syst Soc, IEEE AB The Virtual Mission Operation Framework (VMOF) is one of the project lifecycle engineering process improvement efforts initiated by the institutional technology infrastructure program at JPL. The VMOF is composed of three frameworks: a model integration framework, a simulation framework, and a visualization framework. The model integration framework interfaces with spacecraft system design, mission design, and structure design. The simulation framework interfaces with the operation scenario design, environmental phenomena science, and science payload system design. The visualization framework interfaces with the flight system testbed, the ground system, and the science analysis. The three frameworks of the VMOF collaborate to create a comprehensive virtual mission operation that enables a "validation-in-the-loop" system design process and lifecycle-continuous science-return validation. This paper discusses the technical approaches for each framework implementation, challenges and approaches involved in streamlining mission information access, and on-going activities toward enabling Model-Based Engineering Design in a collaborative distributed environment. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Lee, M (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 7 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-8155-6 J9 AEROSP CONF PROC PY 2004 BP 4015 EP 4025 PG 11 WC Engineering, Aerospace SC Engineering GA BBF75 UT WOS:000225274000407 ER PT S AU Bliss, DA AF Bliss, DA GP ieee TI Reduce costs with multi-mission sequencing and a multi-mission operations system SO 2004 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-6 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 06-13, 2004 CL Big Sky, MT SP Aerosp & Elect Syst Soc, IEEE AB Mission sequencing involves merging science and engineering inputs into an integrated, constraint-checked sequence and producing review and spacecraft command products. This task employs processes, procedures, and tools which have a high degree of commonality across all missions. The JPL Multi-Mission Office (MMO) Mission Planning and Sequencing Team (MPST) has Successfully baselined these processes, procedures, and tools so that they are readily adaptable to missions of varying complexity. As a result, the MPST can quickly assemble a team that provides mission sequencing to very different missions at a fraction of previous costs. This paper will discuss the MMO MPST approach of adapting core processes, procedures, and tools to multiple missions. The paper will then propose extending this multi-mission philosophy to skeleton timeline development, science sequencing, and spacecraft sequencing. Finally, the paper will investigate a multi-mission approach to Mission Operations System (MOS) development. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91011 USA. RP Bliss, DA (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91011 USA. NR 1 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-8155-6 J9 AEROSP CONF PROC PY 2004 BP 4055 EP 4061 PG 7 WC Engineering, Aerospace SC Engineering GA BBF75 UT WOS:000225274000412 ER PT S AU Buehler, MG Some, RR Moynihan, PI VanSant, JT Oberright, JE Dennehy, CJ Brownlow, LW Marshall, MF Radcliffe, T AF Buehler, MG Some, RR Moynihan, PI VanSant, JT Oberright, JE Dennehy, CJ Brownlow, LW Marshall, MF Radcliffe, T GP ieee TI Technologies for affordable SEC missions SO 2004 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-6 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 06-13, 2004 CL Big Sky, MT SP Aerosp & Elect Syst Soc, IEEE AB The influence of technology in reducing spacecraft costs was evaluated by analyzing historical trend data for spacecraft subsystems. The analysis is based on several dozen spacecraft and leads to the conclusion that, on average, the use of technologies that reduce spacecraft power will reduce spacecraft mass and cost. These conclusions are particularly important for NASA's Sun-Earth Connection (SEC) missions where 43,300 kg is projected to be launched over a 19-year period. An example is given where the use of ultra-low power electronics in spacecraft subsystems significantly reduces spacecraft costs by permitting smaller and cheaper subsystems. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Buehler, MG (reprint author), CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. NR 9 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-8155-6 J9 AEROSP CONF PROC PY 2004 BP 4062 EP 4072 PG 11 WC Engineering, Aerospace SC Engineering GA BBF75 UT WOS:000225274000413 ER PT S AU Tralli, DM AF Tralli, DM GP ieee TI Valuation of technology development using a novel workflow approach to compound real options SO 2004 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-6 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 06-13, 2004 CL Big Sky, MT SP Aerosp & Elect Syst Soc, IEEE AB A concept study was undertaken to demonstrate how strategic valuation of a micro-sun sensor development could impact decision-making and planning during maturation of technology from proof-of-concept through validation and demonstration. A workflow of activities that retire risk and ensure technology infusion into a targeted system also prescribes a pseudo-decision tree from which comparison of discounted cash flow (DCF) with compound real options valuation is performed to evaluate the strategic value of the maturation phase. The intent is to identify areas where financial modeling may improve decision-making for integration with technology risk assessment, infusion planning, probabilistic cost estimation, schedule uncertainties and program-level decision tree analysis. DCF and option values expectedly are dominated by assumptions and uncertainty. Nonetheless, the latter preliminarily yields a project value distribution that can exceed DCF by up to $40,000 though typically is below $10,000 for this relatively small $800,000 technology development effort over two years. C1 CALTECH, Jet Prop Lab, Strateg Syst Technol Program, Pasadena, CA 91109 USA. RP Tralli, DM (reprint author), CALTECH, Jet Prop Lab, Strateg Syst Technol Program, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 12 TC 0 Z9 0 U1 0 U2 3 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-8155-6 J9 AEROSP CONF PROC PY 2004 BP 4110 EP 4117 PG 8 WC Engineering, Aerospace SC Engineering GA BBF75 UT WOS:000225274000418 ER PT S AU Forsgren, R AF Forsgren, R GP ieee TI NASA engineering training lessons learned: The course development process from the top and bottom SO 2004 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-6 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 06-13, 2004 CL Big Sky, MT SP Aerosp & Elect Syst Soc, IEEE AB Development of training courses for experienced NASA engineers and technical staff can be a difficult, time-consuming process, especially for course developers who are not employed by the Agency. Here we describe a recently developed method for shortening the roll-out time and improving program quality for new courses in the NASA Engineering Training program. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP Forsgren, R (reprint author), NASA, Glenn Res Ctr, 21000 Brookpk Rd, Cleveland, OH 44135 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-8155-6 J9 AEROSP CONF PROC PY 2004 BP 4118 EP 4124 PG 7 WC Engineering, Aerospace SC Engineering GA BBF75 UT WOS:000225274000419 ER PT S AU Jansma, PA AF Jansma, PA GP ieee TI Got software? What managers and engineers need to know SO 2004 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-6 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 06-13, 2004 CL Big Sky, MT SP Aerosp & Elect Syst Soc, IEEE AB As part of a JPL-wide software quality initiative aimed at addressing the challenges of developing, managing and acquiring software, a team at JPL generated a detailed Software Training Plan for training both managers and engineers. The team took the approach of treating the software training program as though it were a system development task, and went through all the typical phases of system development including requirements, design, implementation, etc. During the requirements collection phase, the team conducted dozens of interviews and identified the specific skills needed. The skills fell into categories such as software management, software engineering, systems engineering and other technical areas. However, an equally important finding was that several "soft" skills were deemed critical for the successful and timely management and implementation of software-intensive systems. This paper discusses JPL's approach and "lessons learned" from planning and delivering a software training program in an engineering and scientific environment. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Jansma, PA (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 11 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-8155-6 J9 AEROSP CONF PROC PY 2004 BP 4144 EP 4154 PG 11 WC Engineering, Aerospace SC Engineering GA BBF75 UT WOS:000225274000422 ER PT S AU Vickers, B AF Vickers, B GP ieee TI Architecting a software architect SO 2004 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-6 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 06-13, 2004 CL Big Sky, MT SP Aerosp & Elect Syst Soc, IEEE AB Software architecture is a relatively new software engineering discipline that has emerged as a response to the growing complexity of software systems and the problems these systems attempt to solve. Software is becoming the dominant component of most aerospace systems and it is necessary for the aerospace software development community to develop new practices, principles, and standards to manage this growing complexity. The Jet Propulsion Laboratory (JPL) has developed and implemented a year-long educational program designed to develop expertise in software architectures and to train future software architects. Now in its third year, the Software Architect Program (SWAP) selects senior software engineers and then apprentices them as software architects. The objective of this paper is to describe the structure of the SWAP, the program's background, how the program has evolved, and the lessons learned from the implementation of this educational program. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Vickers, B (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 9 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-8155-6 J9 AEROSP CONF PROC PY 2004 BP 4155 EP 4161 PG 7 WC Engineering, Aerospace SC Engineering GA BBF75 UT WOS:000225274000423 ER PT S AU Devirian, M AF Devirian, M GP ieee TI An update on NASA's Astronomical Search for Origins Program SO 2004 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-6 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 06-13, 2004 CL Big Sky, MT SP Aerosp & Elect Syst Soc, IEEE AB NASA's Astronomical Search for Origins has been progressing along a roadmap first established in 1996. Key features of that roadmap included technological and scientific stepping stones linking major missions. This paper provides an overview of the current Roadmap version published in 2003, overall status of the program, and discusses top level evolution of the processes for linking these missions. Other speakers/panel members will present more details concerning these issues in this session. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Devirian, M (reprint author), CALTECH, Jet Prop Lab, 180-701 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 5 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-8155-6 J9 AEROSP CONF PROC PY 2004 BP 4181 EP 4185 PG 5 WC Engineering, Aerospace SC Engineering GA BBF75 UT WOS:000225274000426 ER PT S AU Lindensmith, C AF Lindensmith, C GP ieee TI Terrestrial Planet Finder: Technology development plans and progress SO 2004 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-6 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 06-13, 2004 CL Big Sky, MT SP Aerosp & Elect Syst Soc, IEEE AB One of humanity's oldest questions is whether life exists elsewhere in the universe. The Terrestrial Planet Finder (TPF) mission will survey stars in our stellar neighborhood to search for planets and perform spectroscopic measurements to identify potential biomarkers in their atmospheres. TPF is planned for launch around 2015. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Lindensmith, C (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 79-24, Pasadena, CA 91109 USA. NR 3 TC 2 Z9 2 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-8155-6 J9 AEROSP CONF PROC PY 2004 BP 4186 EP 4189 PG 4 WC Engineering, Aerospace SC Engineering GA BBF75 UT WOS:000225274000427 ER PT S AU Dooley, J AF Dooley, J GP ieee TI Technology development for future very large ohservatories SO 2004 IEEE AEROSPACE CONFERENCE PROCEEDINGS, VOLS 1-6 SE IEEE AEROSPACE CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE Aerospace Conference CY MAR 06-13, 2004 CL Big Sky, MT SP Aerosp & Elect Syst Soc, IEEE AB The future very large observatories planned as part of the Astronomical Search for Origins will require significant advances in focal planes, large apertures, active and adaptive wavefront control, and distributed thermal management systems. The Vision Missions and the needed technologies are briefly described. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Dooley, J (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 4 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1095-323X BN 0-7803-8155-6 J9 AEROSP CONF PROC PY 2004 BP 4190 EP 4192 PG 3 WC Engineering, Aerospace SC Engineering GA BBF75 UT WOS:000225274000428 ER PT B AU Parker, J Lyzenga, G Norton, C Tisdale, E Donnellan, A AF Parker, J Lyzenga, G Norton, C Tisdale, E Donnellan, A GP ieee TI A community faulted-crust model using PYRAMED on cluster platforms SO 2004 IEEE INTERNATIONAL CONFERENCE ON CLUSTER COMPUTING LA English DT Proceedings Paper CT IEEE International Conference on Cluster Computing CY SEP 20-23, 2004 CL San Diego, CA SP IEEE Comp Soc, TFCC C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Parker, J (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91125 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU INST CHEMICAL ENGINEERS PI RUGBY PA GEORGE E DAVIS BLDG, 165-171 RAILWAY TERRACE, RUGBY CV21 3HQ, ENGLAND BN 0-7803-8694-9 PY 2004 BP 491 EP 491 DI 10.1109/CLUSTR.2004.1392656 PG 1 WC Computer Science, Theory & Methods SC Computer Science GA BBH75 UT WOS:000225570600058 ER PT B AU Gray, AA AF Gray, AA GP ieee TI Maximum A-posteriori estimation of sub-sample timing with binary modulation, arbitrary pulse shaping, and AWGN SO 2004 IEEE INTERNATIONAL CONFERENCE ON COMMUNICATIONS, VOLS 1-7 LA English DT Proceedings Paper CT IEEE International Conference on Communications (ICC 2004) CY JUN 20-24, 2004 CL Paris, FRANCE SP IEEE, Alcatel, France Telecom, Cegetel Grp, Thales, Bouygues Telecom, Siemens, Siemens Mobile, Mitsubishi, GET, IEEE Commun Soc, EUREL, ICC GLOBECOM, See AB The maximum a-posteriori estimator for discrete-time sub-sample timing recovery is derived for non-return to zero pulse-shaped base-band waveforms and the additive white Gaussian noise channel. With a training sequence the estimator may be modeled as an M-ary waveform receiver. The performance of the estimator is determined through Monte-Carlo simulation for an example pulse shape for both random pulses and with the simplifying case when a training sequence is used These results are compared with the Union bound for M-ary waveform communications; at high post-integration signal-to-noise ratios the performance of the estimator and the Union bound are close for the case of random pulses (data) and approximately equal in the case of a training sequence. C1 CALTECH, Jet Propuls Lab, Pasadena, CA 91101 USA. RP Gray, AA (reprint author), CALTECH, Jet Propuls Lab, 4800 Oak Grove Dr,MS 238-343, Pasadena, CA 91101 USA. NR 9 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-8533-0 PY 2004 BP 2857 EP 2863 DI 10.1109/ICC.2004.1313051 PG 7 WC Telecommunications SC Telecommunications GA BAT52 UT WOS:000223459600557 ER PT B AU Stoica, A Keymeulen, D Arslan, T Duong, V Zebulum, R Ferguson, I Guo, X AF Stoica, A Keymeulen, D Arslan, T Duong, V Zebulum, R Ferguson, I Guo, X BE Diessel, O Williams, J TI Self-recovery experiments in extreme environments using a field programmable transistor array SO 2004 IEEE INTERNATIONAL CONFERENCE ON FIELD-PROGRAMMABLE TECHNOLOGY, PROCEEDINGS LA English DT Proceedings Paper CT 3rd International Conference on Field-Programmable Technology CY DEC 06-08, 2004 CL Univ Queensland, Brisbane, AUSTRALIA SP Sch ITEE, Univ Queensland, IEEE Electron Devices Soc, IEEE Queensland Sect, Reg 10 HO Univ Queensland ID EVOLUTION AB Temperature and radiation tolerant electronics, as well as long life survivability are key capabilities required for future NASA missions. Current approaches to electronics for extreme environments focus on component level robustness and hardening. However, current technology can only ensure very limited lifetime in extreme environments. This paper describes novel experiments that allow adaptive in-situ circuit redesign/reconfiguration during operation in extreme temperature and radiation environments. This technology would complement material/device advancements and increase the mission capability to survive harsh environments. The approach is demonstrated on a mixed-signal programmable chip (FPTA-2), which recovers functionality for temperatures until 280 degrees C and with total radian. on dose tip to 250kRad. C1 Jet Prop Lab, Pasadena, CA 91109 USA. RP Arslan, T (reprint author), Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 8 TC 1 Z9 1 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-8651-5 PY 2004 BP 9 EP 15 PG 7 WC Computer Science, Hardware & Architecture SC Computer Science GA BBR17 UT WOS:000227342000002 ER PT B AU Berenji, H Wang, Y Vengerov, D Langari, R Jamshidi, M AF Berenji, H Wang, Y Vengerov, D Langari, R Jamshidi, M GP IEEE TI Using gated experts in fault diagnosis and prognosis SO 2004 IEEE INTERNATIONAL CONFERENCE ON FUZZY SYSTEMS, VOLS 1-3, PROCEEDINGS SE IEEE International Conference on Fuzzy Systems (FUZZ-IEEE) LA English DT Proceedings Paper CT Annual IEEE International Conference on Fuzzy Systems CY JUL 25-29, 2004 CL Budapest, HUNGARY SP IEEE ID AUTOASSOCIATIVE NEURAL NETWORKS AB Three individual experts have been developed based on Extended Auto Associative Neural Networks (EAANN), Kohonen Self Organizing Maps (KSOM), and the Radial Basis Function based Clustering (RBFC) algorithms. An integrated method is proposed later to combine the set of individual experts managed by a Gated Experts algorithm, which assigns the experts based on their best performance regions. We have used a Matlab Simulink model of a chiller system and applied the individual experts and the integrated method to detect and recover sensor errors. It has been shown that the integrated method gets better performance in diagnostics and prognostics compared with each individual expert. C1 NASA, Intelligent Inference Syst Corp, Moffett Field, CA 94035 USA. RP Berenji, H (reprint author), NASA, Intelligent Inference Syst Corp, MS 566-109, Moffett Field, CA 94035 USA. NR 9 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-8353-2 J9 IEEE INT CONF FUZZY PY 2004 BP 463 EP 467 PG 5 WC Computer Science, Artificial Intelligence SC Computer Science GA BBD06 UT WOS:000224959100082 ER PT S AU Huber, E Baker, K AF Huber, E Baker, K GP IEEE TI Using a hybrid of silhouette and range templates for real-time pose estimation SO 2004 IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION, VOLS 1- 5, PROCEEDINGS SE IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION LA English DT Proceedings Paper CT IEEE International Conference on Robotics and Automation CY APR 26-MAY 01, 2004 CL New Orleans, LA SP IEEE Robot & Automat Soc, IEEE DE pose estimation; template matching; machine vision; Robonaut ID STEREO AB Pose estimation is a fundamental problem in machine vision. Silhouette and 3d point matching are two of the many popular methods for attacking this problem. The appearance of a silhouette is highly sensitive to changes in the object's planer (WRT the object plane) location and orientation. Therefore, silhouette matching can be used to accurately measure 3 of the 6 pose parameters. The appearance of a silhouette is less sensitive to DOFs that produce out-of-plane motion and so it enables only rough measurement of these 3 pose parameters. 3d point matching, which employs range data, can be used to accurately determine the 3 out-of-plane pose parameters. However, to recognize specific 3d points, one must typically make strong assumptions about the types of features present on an object's surface. Our goal is to solve the more general pose problem, where specific types of features cannot be relied upon because they might not be present. This paper first introduces a novel approach to silhouette matching which employs binary range maps and statistically generated templates. It then describes a hybrid method for template-based pose estimation that leverages silhouette matching for 3 of 6 pose parameters. The remaining 3 parameters are determined using range measurements that do not require the presence of specific features or artifacts. This approach provides a high degree of precision in all 6 DOFs, yet its computational efficiency enables real-time performance. Results from dexterous robot (Robonaut) experiments, using this pose algorithm, are discussed. C1 NASA, JSC, Metr Inc, Houston, TX 77058 USA. RP Huber, E (reprint author), NASA, JSC, Metr Inc, Houston, TX 77058 USA. NR 7 TC 0 Z9 0 U1 1 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1050-4729 BN 0-7803-8232-3 J9 IEEE INT CONF ROBOT PY 2004 BP 1652 EP 1657 DI 10.1109/ROBOT.2004.1308061 PG 6 WC Automation & Control Systems; Computer Science, Artificial Intelligence; Robotics SC Automation & Control Systems; Computer Science; Robotics GA BAE24 UT WOS:000221794800267 ER PT S AU Martin, TB Ambrose, RO Diftler, MA Platt, R Butzer, MJ AF Martin, TB Ambrose, RO Diftler, MA Platt, R Butzer, MJ GP IEEE TI Tactile gloves for autonomous grasping with the NASA/DARPA Robonaut SO 2004 IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION, VOLS 1- 5, PROCEEDINGS SE IEEE International Conference on Robotics and Automation ICRA LA English DT Proceedings Paper CT IEEE International Conference on Robotics and Automation CY APR 26-MAY 01, 2004 CL New Orleans, LA SP IEEE Robot & Automat Soc, IEEE DE tactile glove; robot hand; autonomous grasping; humanoid ID SPACE AB Tactile data from rugged gloves are providing the foundation for developing autonomous grasping skills for the NASA/DARPA Robonaut, a dexterous humanoid robot. These custom gloves compliment the human like dexterity available in the Robonaut hands. Multiple versions of the gloves are discussed, showing a progression in using advanced materials and construction techniques to enhance sensitivity and overall sensor coverage. The force data provided by the gloves can be used to improve dexterous, tool and power grasping primitives. Experiments with the latest gloves focus on the use of tools, specifically a power drill used to approximate an astronaut's torque tool. C1 NASA, Lyndon B Johnson Space Ctr, Automat Robot & Simulat Div, Houston, TX 77058 USA. RP NASA, Lyndon B Johnson Space Ctr, Automat Robot & Simulat Div, Houston, TX 77058 USA. EM tbmartin@ems.jsc.nasa.gov; rambrose@ems.jsc.nasa.gov; mdiftler@ems.jsc.nasa.gov; rplatt@cs.umass.edu; mbutzer@oss.oceaneering.com NR 24 TC 14 Z9 15 U1 2 U2 6 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1050-4729 BN 0-7803-8232-3 J9 IEEE INT CONF ROBOT PY 2004 BP 1713 EP 1718 DI 10.1109/ROBOT.2004.1308071 PG 6 WC Automation & Control Systems; Computer Science, Artificial Intelligence; Robotics SC Automation & Control Systems; Computer Science; Robotics GA BAE24 UT WOS:000221794800277 ER PT S AU Ambrose, RO Savely, RT Michael, S Diftler, MA Spain, I Radford, N AF Ambrose, RO Savely, RT Michael, S Diftler, MA Spain, I Radford, N GP IEEE TI Mobile manipulation using NASA's Robonaut SO 2004 IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION, VOLS 1- 5, PROCEEDINGS SE IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION LA English DT Proceedings Paper CT IEEE International Conference on Robotics and Automation CY APR 26-MAY 01, 2004 CL New Orleans, LA SP IEEE Robot & Automat Soc, IEEE DE mobile; manipulation; robonaut; segway; space AB The Johnson Space Center has developed a new mobile manipulation system with the combination of a Robonaut upper body mounted onto a Segway mobile base. The objective is to study a fluid and coordinated control of dexterous limbs on a mobile robot. The system has been demonstrated interacting with people, tools, and urban interfaces built for humans. Human interactions have included manually exchanging objects with humans, following people, and tracking people with hand held objects such as flashlights. Like other configurations of the Robonaut family, the upper body provides dexterity for using tools such as wire cutters, shovels, space flight gear, and handling flexible tethers and fabrics. The Segway base is a custom version called the Robotic Mobility Platform (RMP) built for DARPA, and provided to NASA for this collaborative effort. The RMP's active balance gives Robonaut a relatively small footprint for its height, allowing it to pass through doors and elevators built for humans, and use wheelchair accessible ramps and lifts. Lessons learned from this development will be presented to improve the design of future mobile manipulation systems, and the Segway base provides mobility to Robonaut for Earth based testing. C1 NASA, Lyndon B Johnson Space Ctr, Automat Robot & Simulat Div, Houston, TX 77058 USA. RP Ambrose, RO (reprint author), NASA, Lyndon B Johnson Space Ctr, Automat Robot & Simulat Div, Houston, TX 77058 USA. NR 7 TC 27 Z9 28 U1 1 U2 4 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1050-4729 BN 0-7803-8232-3 J9 IEEE INT CONF ROBOT PY 2004 BP 2104 EP 2109 DI 10.1109/ROBOT.2004.1308134 PG 6 WC Automation & Control Systems; Computer Science, Artificial Intelligence; Robotics SC Automation & Control Systems; Computer Science; Robotics GA BAE24 UT WOS:000221794800340 ER PT S AU Elfes, A Hall, JL Montgomery, JF Bergh, CF Dudik, BA AF Elfes, A Hall, JL Montgomery, JF Bergh, CF Dudik, BA GP IEEE TI Towards a substantially autonomous aerobot for exploration of titan SO 2004 IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION, VOLS 1- 5, PROCEEDINGS SE IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION LA English DT Proceedings Paper CT IEEE International Conference on Robotics and Automation CY APR 26-MAY 01, 2004 CL New Orleans, LA SP IEEE Robot & Automat Soc, IEEE DE unmanned aerial vehicle; robotic airship; planetary exploration; titan AB Robotic lighter-than-air vehicles, or aerobots, are strategic surveying and instrument deployment platforms for the exploration of planets and moons with an atmosphere, such as Venus, Mars and Titan. Aerobots are characterized by modest power requirements, extended mission duration and long traverse capabilities, and the ability to transport and deploy scientific instruments and in-situ laboratory facilities over vast distances. With the arrival of the Huygens probe at Saturn's moon Titan in early 2005, there is considerable interest in a follow-on mission that would use a substantially autonomous aerobot to explore Titan's surface. In this paper, we discuss rust steps towards the development of an autonomy architecture and a core set of perception, reasoning and control technologies for a future Titan aerobot. We provide an overview of the autonomy architecture, which integrates perception-based flight planning and control, vehicle health monitoring and safing, long-range mission planning and monitoring, and vision-based science site surveying. We describe the JPL aerobot and the onboard avionics architecture testbeds, and conclude with results from initial teleoperated test flights. C1 Jet Prop Lab, Pasadena, CA 91109 USA. RP Elfes, A (reprint author), Jet Prop Lab, Pasadena, CA 91109 USA. RI Elfes, Alberto/E-2463-2011 OI Elfes, Alberto/0000-0003-2433-995X NR 19 TC 3 Z9 3 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1050-4729 BN 0-7803-8232-3 J9 IEEE INT CONF ROBOT PY 2004 BP 2535 EP 2541 DI 10.1109/ROBOT.2004.1307443 PG 7 WC Automation & Control Systems; Computer Science, Artificial Intelligence; Robotics SC Automation & Control Systems; Computer Science; Robotics GA BAE24 UT WOS:000221794800409 ER PT S AU Washington, R Lees, D AF Washington, R Lees, D GP IEEE TI Utility-based plan insertion for continuous resources SO 2004 IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION, VOLS 1- 5, PROCEEDINGS SE IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION LA English DT Proceedings Paper CT IEEE International Conference on Robotics and Automation CY APR 26-MAY 01, 2004 CL New Orleans, LA SP IEEE Robot & Automat Soc, IEEE AB In this paper, we consider the problem of evaluating plan fragments for insertion into an existing plan. Preparing a plan that is robust to variations in continuous resources requires considering the uncertainty over these resources. For some situations, it is impractical to add branches to the plan a priori, because such situations may arise at any of a large number of points in execution. Adding all these potential branches to an existing plan would require an immense computational effort and result in a huge plan. In such a case, it makes more sense to precompute a plan fragment to react to such a situation and allow the execution system to insert the plan fragment into its current plan when appropriate. The problem can thus be seen as a restricted form of plan merging, but with the addition of uncertainty and continuous resources, and the criterion of maximing utility rather than absolute goal achievement. We formalize the problem and introduce an efficient solution method, incremental bounds refinement, that iteratively narrows bounds on the expected value of adding a branch until it can be discriminated from the original plan. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Washington, R (reprint author), NASA, Ames Res Ctr, MS 269-3, Moffett Field, CA 94035 USA. NR 7 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1050-4729 BN 0-7803-8232-3 J9 IEEE INT CONF ROBOT PY 2004 BP 2993 EP 2999 DI 10.1109/ROBOT.2004.1307516 PG 7 WC Automation & Control Systems; Computer Science, Artificial Intelligence; Robotics SC Automation & Control Systems; Computer Science; Robotics GA BAE24 UT WOS:000221794800482 ER PT S AU McDowell, P Bourgeois, B Iyengar, SS AF McDowell, P Bourgeois, B Iyengar, SS GP IEEE TI Formation maneuvering using passive acoustic communications SO 2004 IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION, VOLS 1- 5, PROCEEDINGS SE IEEE INTERNATIONAL CONFERENCE ON ROBOTICS AND AUTOMATION LA English DT Proceedings Paper CT IEEE International Conference on Robotics and Automation CY APR 26-MAY 01, 2004 CL New Orleans, LA SP IEEE Robot & Automat Soc, IEEE DE component AB Interest in the use of unmanned underwater vehicles (UUVs) for both commercial and military uses is growing. Control of UUVs poses a difficult problem because traditional methods of communication and navigation, i.e. radio and GPS, are not effective due to the properties of seawater. Control and communication algorithms were developed to carry out multiple UUV formation maneuvering using acoustic communications and first tested in computer simulation and then on mobile robots. Three control schemes, classic logic, behavior, and neural network were tested in line formations in both simulator and lab environments. Results and issues are discussed along with future directions. C1 USN, Res Lab, Stennis Space Ctr, Stennis Space Ctr, MS 39529 USA. RP McDowell, P (reprint author), USN, Res Lab, Stennis Space Ctr, Stennis Space Ctr, MS 39529 USA. NR 6 TC 1 Z9 1 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1050-4729 BN 0-7803-8232-3 J9 IEEE INT CONF ROBOT PY 2004 BP 3843 EP 3848 DI 10.1109/ROBOT.2004.1308867 PG 6 WC Automation & Control Systems; Computer Science, Artificial Intelligence; Robotics SC Automation & Control Systems; Computer Science; Robotics GA BAE24 UT WOS:000221794800617 ER PT S AU Callantine, TJ AF Callantine, TJ GP IEEE TI Air traffic management system domain and control strategy analysis SO 2004 IEEE INTERNATIONAL CONFERENCE ON SYSTEMS, MAN & CYBERNETICS, VOLS 1-7 SE IEEE INTERNATIONAL CONFERENCE ON SYSTEMS, MAN, AND CYBERNETICS, CONFERENCE PROCEEDINGS LA English DT Proceedings Paper CT IEEE International Conference on Systems, Man and Cybernetics CY OCT 10-13, 2004 CL The Hague, NETHERLANDS SP IEEE DE air traffic management; control strategies; fast-time simulation; Flight Management System; operator agent models AB This paper describes a simulation tool developed to aid the analysis of Air Traffic Management domains and potential air traffic control strategies. The simulation represents aircraft and automated air traffic control support tool functionality based on a computational model of aircraft Flight Management System trajectories. It simulates the effects of environmental disturbances and air traffic controller intervention on air traffic in fast time. The paper outlines a methodology that leverages these capabilities to help with tool design and evaluation, and discusses the results of preliminary simulations aimed toward using the proposed methodology for characterizing the effectiveness of particular strategy-tool combinations for supporting more efficient terminal-area Air Traffic Management. This research is supported by NASA's Vehicle Systems Program Quiet Aircraft Technology project and Airspace Systems Program Advanced Air Transportation Technology project. C1 San Jose State Univ, NASA Ames Res Ctr, Human Factors & Technol Div, Moffett Field, CA USA. RP Callantine, TJ (reprint author), San Jose State Univ, NASA Ames Res Ctr, Human Factors & Technol Div, Moffett Field, CA USA. NR 14 TC 1 Z9 1 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1062-922X BN 0-7803-8566-7 J9 IEEE SYS MAN CYBERN PY 2004 BP 6268 EP 6273 PG 6 WC Automation & Control Systems; Computer Science, Artificial Intelligence; Computer Science, Cybernetics; Robotics SC Automation & Control Systems; Computer Science; Robotics GA BBP32 UT WOS:000226863301055 ER PT S AU Tumer, K Agogino, AK AF Tumer, K Agogino, AK GP ieee TI Overcoming communication restrictions in collectives SO 2004 IEEE INTERNATIONAL JOINT CONFERENCE ON NEURAL NETWORKS, VOLS 1-4, PROCEEDINGS SE IEEE International Joint Conference on Neural Networks (IJCNN) LA English DT Proceedings Paper CT IEEE International Joint Conference on Neural Networks (IJCNN) CY JUL 25-29, 2004 CL Budapest, HUNGARY SP IEEE, IEEE Neural Networks Soc, Hungarian Acad Sci, Comp & Automat Res Inst, Katholieke Univ Leuven, Republic Hungary, Natl Commun & Informat Council AB The performance of distributed systems generally depend on the actions and interactions of a large number of independent components (e.g., agents, neurons). Such "collectives" are often subject to communication restrictions, making it difficult for the components to coordinate their actions to provide good system level performance. In this article we address that coordination problem and derive four agent utility functions that make different tradeoffs between alignedness between agent and system utilities and the signal-to-noise each agent encounters. The results show that these utility functions outperform both traditional methods and previous collective-based methods by up to 75% in systems with communication restrictions. C1 NASA, Ames Res Ctr, Computat Sci Div, Moffett Field, CA 94035 USA. RP Tumer, K (reprint author), NASA, Ames Res Ctr, Computat Sci Div, Mailstop 269-4, Moffett Field, CA 94035 USA. NR 22 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1098-7576 BN 0-7803-8359-1 J9 IEEE IJCNN PY 2004 BP 1127 EP 1132 PG 6 WC Computer Science, Artificial Intelligence; Computer Science, Cybernetics SC Computer Science GA BBC97 UT WOS:000224941900195 ER PT B AU Chen, Y Guertin, SM Petkov, M Nguyen, DN Novak, F AF Chen, Y Guertin, SM Petkov, M Nguyen, DN Novak, F GP ieee TI A chip and pixel qualification methodology on imaging sensors SO 2004 IEEE INTERNATIONAL RELIABILITY PHYSICS SYMPOSIUM PROCEEDINGS LA English DT Proceedings Paper CT 42nd Annual IEEE International Reliability Physics Symposium CY APR 25-29, 2004 CL Phoenix, AZ SP IEEE Elect Devices Soc, IEEE Reliabil Soc AB This paper presents a qualification methodology on imaging sensors. In addition to overall chip reliability characterization based on sensor's overall figure of merit, such as Dark Rate, Linearity, Dark Current Non-Uniformity, Fixed Pattern Noise and Photon Response Non-Uniformity, a simulation technique is proposed and used to project pixel reliability. The projected pixel reliability is directly related to imaging quality and provides additional sensor reliability information and performance control. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Chen, Y (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,MS 303-230, Pasadena, CA 91109 USA. NR 12 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-8315-X PY 2004 BP 435 EP 439 DI 10.1109/RELPHY.2004.1315367 PG 5 WC Engineering, Electrical & Electronic SC Engineering GA BAG82 UT WOS:000222139900076 ER PT B AU Teverovsky, A AF Teverovsky, A GP ieee TI Effect of vacuum on high-temperature degradation of gold/aluminum wire bonds in PEMs SO 2004 IEEE INTERNATIONAL RELIABILITY PHYSICS SYMPOSIUM PROCEEDINGS LA English DT Proceedings Paper CT 42nd Annual IEEE International Reliability Physics Symposium CY APR 25-29, 2004 CL Phoenix, AZ SP IEEE Elect Devices Soc, IEEE Reliabil Soc ID RELIABILITY AB Gold/aluminum wire bond degradation is one of the major failure mechanisms limiting reliability of plastic encapsulated microcircuits (PEMs) at high temperatures. It is known also that oxidative degradation is the major cause of failures in epoxy composite materials; however, the effect of oxygen and/or vacuum conditions on degradation of PEMs has not been studied yet. In this work, three groups of linear devices have been subjected to high-temperature storage in convection air chambers and in a vacuum chamber. Electrical characteristics of the devices, variations of the wire bond contact resistances, mass losses of the packages, and thermo-mechanical characteristics of the molding compounds were measured periodically during the testing. The results showed that high-temperature storage in vacuum and air conditions changed thermo-mechanical characteristics of molding compounds in a similar way; however, the failure rates and the degree of wire bond degradation for parts stored in air was significantly larger than for parts stored in the vacuum chamber. A mechanism of Au/Al wire bond failures in PEMs at high temperatures, the role of oxygen, and non-linearity of the degradation rate at a certain critical temperature above the glass transition temperature of molding compounds are discussed. C1 NASA, Goddard Space Flight Ctr, QSS Grp Inc, Greenbelt, MD 20771 USA. RP Teverovsky, A (reprint author), NASA, Goddard Space Flight Ctr, QSS Grp Inc, Code 562, Greenbelt, MD 20771 USA. NR 17 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-8315-X PY 2004 BP 547 EP 556 DI 10.1109/RELPHY.2004.1315388 PG 10 WC Engineering, Electrical & Electronic SC Engineering GA BAG82 UT WOS:000222139900097 ER PT B AU Fang, WC Jin, MY AF Fang, WC Jin, MY GP IEEE TI On board processor development for NASA'S spacebone imaging radar with VLSI system-on-chip technology SO 2004 IEEE INTERNATIONAL SYMPOSIUM ON CIRCUITS AND SYSTEMS, VOL 2, PROCEEDINGS LA English DT Proceedings Paper CT IEEE International Symposium on Circuits and Systems CY MAY 23-26, 2004 CL Vancouver, CANADA SP IEEE, Circuits & Syst Soc AB This paper reports a preliminary study result of an on-board spaceborne SAR processor. It consists of a processing requirement analysis, functional specifications, and implementation with VLSI system-on-chip technology. Finally, a minimum version of this VLSI on-board processor designed for performance evaluation and for partial demonstration is illustrated. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Fang, WC (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 4 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA PY 2004 BP 901 EP 904 PG 4 WC Computer Science, Artificial Intelligence; Engineering, Electrical & Electronic SC Computer Science; Engineering GA BAP43 UT WOS:000223124000226 ER PT B AU Gray, AA Hoy, SD Ghuman, P AF Gray, AA Hoy, SD Ghuman, P GP IEEE TI Adaptive LMS processing architectures employing frequency domain sub-convolution SO 2004 IEEE INTERNATIONAL SYMPOSIUM ON CIRCUITS AND SYSTEMS, VOL 3, PROCEEDINGS LA English DT Proceedings Paper CT IEEE International Symposium on Circuits and Systems CY MAY 23-26, 2004 CL Vancouver, CANADA SP IEEE, Circuits & Syst Soc AB This paper provides an overview of a low-complexity, parameterized, and discrete-time processing architecture for realizing a frequency domain least-mean squares (LMS) complex equalizer [1, 2]. The realization results in lower complexity implementation in digital very large scale integrated (VLSI) circuits. The architecture incorporates a lossless sub-convolution method, digital vector processing, specialized FFT-IFFT hardware architectures, and the discrete Fourier transform-in verse discrete Fourier transform (DFT-IDFT) overlap and save filter method [3]. A key property of the new architecture is that the equalizer tap length may be chosen completely independently of the FFT-IFFT lengths and input data block lengths. Theoretically unlimited tap lengths are possible with short FFT-IFFT pairs. It. will be demonstrated that the new parallel architecture is very well suited for processing multi-Gbps digital communication data rates with relatively low speed CMOS hardware. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Gray, AA (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 12 TC 0 Z9 0 U1 1 U2 2 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-8251-X PY 2004 BP 617 EP 620 PG 4 WC Computer Science, Artificial Intelligence; Computer Science, Hardware & Architecture; Engineering, Electrical & Electronic SC Computer Science; Engineering GA BAP12 UT WOS:000223102200155 ER PT B AU Kolano, PZ AF Kolano, PZ GP IEEE TI Surfer: An extensible pull-based framework for resource selection and ranking SO 2004 IEEE INTERNATIONAL SYMPOSIUM ON CLUSTER COMPUTING AND THE GRID - CCGRID 2004 LA English DT Proceedings Paper CT 4th IEEE/ACM International Symposium on Cluster Computing and the Grid (CCG 2004) CY APR 19-22, 2004 CL Chicago, IL SP IEEE, ACM AB Grid computing aims to connect large numbers of geographically and organizationally distributed resources to increase computational power, resource utilization, and resource accessibility. In order to effectively utilize grids, users need to be connected to the best available resources at any given time. As grids are in constant flux, users cannot be expected to keep tip with the configuration and status of the grid, thus they must be provided with automatic resource brokering for selecting and ranking resources meeting constraints and preferences they specify. This paper presents a new OGSI-compliant resource selection and ranking framework called Surfer that has been implemented as part of NASA's Information Power Grid (IPG) project. Surfer is highly extensible and may be integrated into any grid environment by adding information providers knowledgeable about that environment. Surfer invisibly and seamlessly correlates results from different providers into a single unified view seen by the user. C1 NASA, Ames Res Ctr, Adv Supercomp Div, Moffett Field, CA 94035 USA. RP Kolano, PZ (reprint author), NASA, Ames Res Ctr, Adv Supercomp Div, M-S 258-6, Moffett Field, CA 94035 USA. NR 19 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-8430-X PY 2004 BP 563 EP 571 PG 9 WC Computer Science, Theory & Methods SC Computer Science GA BAN02 UT WOS:000222915200073 ER PT B AU Thorpe, J Andrews, K Dolinar, S AF Thorpe, J Andrews, K Dolinar, S GP IEEE TI Methodologies for designing LDPC codes using protographs and circulants SO 2004 IEEE INTERNATIONAL SYMPOSIUM ON INFORMATION THEORY, PROCEEDINGS LA English DT Proceedings Paper CT IEEE International Symposium on Information Theory CY JUN 27-JUL 02, 2004 CL Chicago, IL SP IEEE, IEEE Informat Theory Soc, Motorola Labs, Qualcomm, Broadcom, IBM Res, Texas Instruments, Microsoft, DARPA, NSF, ONR, Dept Navy Sci & Technol, Flarion, Caltech, Lee Ctr Adv Network AB A method is presented for constructing LDPC codes with excellent performance, simple hardware implementation, low encoder complexity, and which can be concisely documented. The simple code structure is achieved by using a base graph, expanded with circulants. The base graph is chosen by computer search using simulated annealing, driven by density evolution's decoding threshold as determined by the reciprocal channel approximation. To build a full parity check matrix, each edge of the base graph is replaced by a circulant permutation, chosen to maximize loop length by using a Viterbi-like algorithm. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Thorpe, J (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 6 TC 3 Z9 3 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-8280-3 PY 2004 BP 238 EP 238 PG 1 WC Computer Science, Information Systems; Computer Science, Theory & Methods; Telecommunications SC Computer Science; Telecommunications GA BAQ48 UT WOS:000223202600238 ER PT B AU Lee, JKS Lee, B Thorpe, J Andrews, K Dolinar, S Hamkins, J AF Lee, JKS Lee, B Thorpe, J Andrews, K Dolinar, S Hamkins, J GP IEEE TI A scalable architecture of a structured LDPC decoder SO 2004 IEEE INTERNATIONAL SYMPOSIUM ON INFORMATION THEORY, PROCEEDINGS LA English DT Proceedings Paper CT IEEE International Symposium on Information Theory CY JUN 27-JUL 02, 2004 CL Chicago, IL SP IEEE, IEEE Informat Theory Soc, Motorola Labs, Qualcomm, Broadcom, IBM Res, Texas Instruments, Microsoft, DARPA, NSF, ONR, Dept Navy Sci & Technol, Flarion, Caltech, Lee Ctr Adv Network AB We present a scalable decoding architecture for a certain class of structured LDPC codes. The codes are designed using a small (n, r) protograph that is replicated Z times to produce a decoding graph for a (Z x n, Z x r) code. Using this architecture, we have implemented a decoder for a (4096,2048) LDPC code on a Xilinx Virtex-II 2000 FPGA, and achieved decoding speeds of 31 Mbps with 10 fixed iterations. The implemented message-passing algorithm uses an optimized 3-bit non-uniform quantizer that allows near floating point performance in the waterfall region, with drastically smaller hardware implementation requirements. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Lee, JKS (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91125 USA. NR 1 TC 7 Z9 7 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-8280-3 PY 2004 BP 292 EP 292 PG 1 WC Computer Science, Information Systems; Computer Science, Theory & Methods; Telecommunications SC Computer Science; Telecommunications GA BAQ48 UT WOS:000223202600292 ER PT B AU Hamkins, J Moision, B AF Hamkins, J Moision, B GP IEEE TI Multipulse PPM on memoryless channels SO 2004 IEEE INTERNATIONAL SYMPOSIUM ON INFORMATION THEORY, PROCEEDINGS LA English DT Proceedings Paper CT IEEE International Symposium on Information Theory CY JUN 27-JUL 02, 2004 CL Chicago, IL SP IEEE, IEEE Informat Theory Soc, Motorola Labs, Qualcomm, Broadcom, IBM Res, Texas Instruments, Microsoft, DARPA, NSF, ONR, Dept Navy Sci & Technol, Flarion, Caltech, Lee Ctr Adv Network AB We examine several properties of n-pulse pulse position modulation (PPM) [1] on memoryless channels. We derive the maximum likelihood decision rule and an exact expression for the symbol error rate for n greater than or equal to 1, generalizing previous results [2, 3]. A capacity comparison indicates that multipulse PPM does not produce appreciable gains over conventional PPM except at high average power. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Hamkins, J (reprint author), CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. NR 5 TC 2 Z9 2 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-8280-3 PY 2004 BP 336 EP 336 PG 1 WC Computer Science, Information Systems; Computer Science, Theory & Methods; Telecommunications SC Computer Science; Telecommunications GA BAQ48 UT WOS:000223202600336 ER PT B AU Hamkins, J Klimesh, M McEliece, R Moision, B AF Hamkins, J Klimesh, M McEliece, R Moision, B GP IEEE TI Capacity of the generalized PPM channel SO 2004 IEEE INTERNATIONAL SYMPOSIUM ON INFORMATION THEORY, PROCEEDINGS LA English DT Proceedings Paper CT IEEE International Symposium on Information Theory CY JUN 27-JUL 02, 2004 CL Chicago, IL SP IEEE, IEEE Informat Theory Soc, Motorola Labs, Qualcomm, Broadcom, IBM Res, Texas Instruments, Microsoft, DARPA, NSF, ONR, Dept Navy Sci & Technol, Flarion, Caltech, Lee Ctr Adv Network AB We show the capacity of a generalized pulse position modulation (PPM) channel, where the input vectors may be any set that allows a transitive group of coordinate permutations, is achieved by a uniform input distribution. We derive a simple expression for capacity in terms of the Kullback-Leibler distance for the binary case, and find the asymptote in the PPM order. We prove a subadditivity result for the PPM channel and use it to show PPM capacity is monotonic in the order. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91125 USA. EM hamkins@jpl.nasa.gov; klimesh@jpl.nasa.gov; rjm@systems.caltech.edu; bmoision@jpl.nasa.gov NR 1 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-8280-3 PY 2004 BP 337 EP 337 PG 1 WC Computer Science, Information Systems; Computer Science, Theory & Methods; Telecommunications SC Computer Science; Telecommunications GA BAQ48 UT WOS:000223202600337 ER PT B AU Klimesh, M AF Klimesh, M GP IEEE TI Entropy measures and catalysis of bipartite quantum state transformations SO 2004 IEEE INTERNATIONAL SYMPOSIUM ON INFORMATION THEORY, PROCEEDINGS LA English DT Proceedings Paper CT IEEE International Symposium on Information Theory CY JUN 27-JUL 02, 2004 CL Chicago, IL SP IEEE, IEEE Informat Theory Soc, Motorola Labs, Qualcomm, Broadcom, IBM Res, Texas Instruments, Microsoft, DARPA, NSF, ONR, Dept Navy Sci & Technol, Flarion, Caltech, Lee Ctr Adv Network AB Given probability vectors x and y, necessary and sufficient conditions are given for the existence of a probability vector z such that x circle times y is majorized by y circle times z. This is of interest because the "catalytic majorization" relation is known to be useful in classifying which transformations of jointly held pure quantum states are possible using local operations and classical communication when an additional jointly held state may be specified to facilitate the transformation without being consumed. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Klimesh, M (reprint author), CALTECH, Jet Prop Lab, Mail Stop 238-420, Pasadena, CA 91109 USA. NR 5 TC 3 Z9 3 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-8280-3 PY 2004 BP 357 EP 357 PG 1 WC Computer Science, Information Systems; Computer Science, Theory & Methods; Telecommunications SC Computer Science; Telecommunications GA BAQ48 UT WOS:000223202600357 ER PT B AU Dolinar, S Andrews, K AF Dolinar, S Andrews, K GP IEEE TI Low-density mirror-concatenated codes: A generalization of irregular repeat-and-accumulate codes SO 2004 IEEE INTERNATIONAL SYMPOSIUM ON INFORMATION THEORY, PROCEEDINGS LA English DT Proceedings Paper CT IEEE International Symposium on Information Theory CY JUN 27-JUL 02, 2004 CL Chicago, IL SP IEEE, IEEE Informat Theory Soc, Motorola Labs, Qualcomm, Broadcom, IBM Res, Texas Instruments, Microsoft, DARPA, NSF, ONR, Dept Navy Sci & Technol, Flarion, Caltech, Lee Ctr Adv Network AB Low-density mirror-concatenated (LDMC) codes are defined and shown to be equivalent to low-density parity-check (LDPC) codes. As a generalization of irregular repeat-and-accumulate (IRA) codes, LDMC codes offer a slightly different, but potentially useful, perspective on LDPC codes as concatenated codes. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. EM sam@shannon.jpl.nasa.gov; andrews@shannon.jpl.nasa.gov NR 5 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-8280-3 PY 2004 BP 506 EP 506 PG 1 WC Computer Science, Information Systems; Computer Science, Theory & Methods; Telecommunications SC Computer Science; Telecommunications GA BAQ48 UT WOS:000223202600506 ER PT B AU Savchenkov, AA Matsko, AB Strekalov, D Mohageg, M Ilchenko, VS Maleki, L AF Savchenkov, AA Matsko, AB Strekalov, D Mohageg, M Ilchenko, VS Maleki, L GP ieee TI All-optical photonic oscillator with high-Q whispering gallery mode resonators SO 2004 IEEE INTERNATIONAL TOPICAL MEETING ON MICROWAVE PHOTONICS, TECHNICAL DIGEST LA English DT Proceedings Paper CT International Topical Meeting on Microwave Photonics CY OCT 04-06, 2004 CL Ogunquit, ME SP IEEE Microwave Theory & Tech, IEEE LEOS, Boston Univ Photon Ctr AB We demonstrated low threshold optical photonic hyper-parametric oscillator in a high-Q (10(10)) CaF2 whispering gallery mode resonator which generates stable 8.5 GHz signal. The oscillations result from the resonantly enhanced four wave mixing occurring due to Kerr nonlinearity of the material. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Savchenkov, AA (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 4 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-8492-X PY 2004 BP 205 EP 208 DI 10.1109/MWP.2004.1396875 PG 4 WC Engineering, Electrical & Electronic; Optics SC Engineering; Optics GA BBF46 UT WOS:000225226300054 ER PT S AU Lavelle, JP Schuet, SR Schuet, DJ AF Lavelle, JP Schuet, SR Schuet, DJ GP ieee TI High speed 3D scanner with real-time 3D processing SO 2004 IEEE INTERNATIONAL WORKSHOP ON IMAGING SYSTEMS AND TECHNIQUES (IST) SE IEEE International Workshop on Imaging Systems and Techniques LA English DT Proceedings Paper CT IEEE International Workshop on Imaging Systems and Techniques CY MAY 18-20, 2004 CL Stresa, ITALY SP IEEE Instrumentat & Measurement Soc AB A novel sensor with real-time 3D processing capable of scanning an object at very high speeds (greater than 500,000 3D points/second) and creating high-resolution surface maps has been developed. The ranging technique of Laser Triangulation is implemented with a high-resolution camera, a laser diode, and processing electronics incorporated into a small sensor package that traverses linearly or rotates from a fixed position to scan over an object. Processing is done on board the instrument in real time and the resultant 3D data is transmitted to a PC. The sensing system was developed for the NASA Mars rover program and for the inspection of Shuttle Thermal Protection System (tiles) radiator, and structures. C1 NASA, Ames Res Ctr, Moffett Field, CA 94035 USA. RP Lavelle, JP (reprint author), NASA, Ames Res Ctr, Code SFT, Moffett Field, CA 94035 USA. EM Joseph.P.Lavelle@nasa.gov NR 5 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1558-2809 BN 0-7803-8591-8 J9 I W IMAG SYST TECHNI PY 2004 BP 13 EP 17 DI 10.1109/IST.2004.1397272 PG 5 WC Instruments & Instrumentation; Imaging Science & Photographic Technology SC Instruments & Instrumentation; Imaging Science & Photographic Technology GA BBE16 UT WOS:000225101600003 ER PT S AU Biswas, A Farr, WH AF Biswas, A Farr, WH GP ieee TI Detectors for ground-based reception of laser communications from Mars SO 2004 IEEE LEOS ANNUAL MEETING CONFERENCE PROCEEDINGS, VOLS 1 AND 2 SE IEEE Lasers and Electro-Optics Society (LEOS) Annual Meeting LA English DT Proceedings Paper CT 17th Annual Meeting of the IEEE-Lasers-and-Electro-Optics-Society CY NOV 07-11, 2004 CL Rio Grande, PR SP IEEE Lasers & Electro Opt Soc, IEEE ID SYSTEM AB Ground-based receivers at Earth require single photon counting detectors with 30% photo-detection efficiency (PDE) at 1.06-mum, for optical communications from deep space. Design drivers and detector selection criteria are discussed. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91106 USA. RP Biswas, A (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr MS 161-135, Pasadena, CA 91106 USA. NR 8 TC 1 Z9 1 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1092-8081 BN 0-7803-8557-8 J9 IEEE LEOS ANN MTG PY 2004 BP 74 EP 75 PG 2 WC Optics SC Optics GA BBG19 UT WOS:000225390900037 ER PT B AU O'Bryan, MV Seidleck, CM Carts, MA Howard, JW Kim, HS Forney, JD LaBel, KA Marshall, CJ Reed, RA Sanders, AB Hawkins, DK Cox, SR Buchner, SP Oldham, TR Sutton, J Irwin, TL Rodriguez, E McMorrow, D Kniffin, SD Ladbury, RL Walter, M Palor, C Marshall, PW McCall, M Meyer, S Lintz, J Rodgers, J Mohammed, S Rapchun, D AF O'Bryan, MV Seidleck, CM Carts, MA Howard, JW Kim, HS Forney, JD LaBel, KA Marshall, CJ Reed, RA Sanders, AB Hawkins, DK Cox, SR Buchner, SP Oldham, TR Sutton, J Irwin, TL Rodriguez, E McMorrow, D Kniffin, SD Ladbury, RL Walter, M Palor, C Marshall, PW McCall, M Meyer, S Lintz, J Rodgers, J Mohammed, S Rapchun, D GP ieee TI Current single event effects results for candidate spacecraft electronics for NASA SO 2004 IEEE RADIATION EFFECTS DATA WORKSHOP, WORKSHOP RECORD LA English DT Proceedings Paper CT IEEE Radiation Effects Data Workshop ( REDW) held in conjunction with the IEEE Nuclear and Space Radiation Effects Conference (NSREC) CY JUL 22, 2004 CL Atlanta, GA SP IEEE Nucl & Plasma Sci Soc, IEEE DE component; SEE; spacecraft electronics; proton; heavy ion; single event effects ID PULSED-LASER AB We present data on the vulnerability of a variety of candidate spacecraft electronics to proton and heavy ion induced single event effects. Devices tested include digital, analog, linear bipolar, and hybrid devices, among others. C1 NASA, Goddard Space Flight Ctr, Raytheon Co, ITSS, Greenbelt, MD USA. RP O'Bryan, MV (reprint author), NASA, Goddard Space Flight Ctr, Raytheon Co, ITSS, Code 561-4, Greenbelt, MD USA. NR 12 TC 2 Z9 2 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-8697-3 PY 2004 BP 10 EP 18 DI 10.1109/REDW.2004.1352897 PG 9 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA BBN14 UT WOS:000226254000003 ER PT B AU Cochran, DJ Buchner, SP Irwin, TL LaBel, KA Marshall, CJ Reed, RA Sanders, AB Hawkins, DK Flanigan, RJ Cox, SR Howard, JW Kim, HS Forney, JD Kniffin, SD Ladbury, RL Palor, CD O'Bryan, MV Carts, MA Poivey, CF Marshall, PW AF Cochran, DJ Buchner, SP Irwin, TL LaBel, KA Marshall, CJ Reed, RA Sanders, AB Hawkins, DK Flanigan, RJ Cox, SR Howard, JW Kim, HS Forney, JD Kniffin, SD Ladbury, RL Palor, CD O'Bryan, MV Carts, MA Poivey, CF Marshall, PW GP ieee TI Current total ionizing dose results and displacement damage results for candidate spacecraft electronics for NASA SO 2004 IEEE RADIATION EFFECTS DATA WORKSHOP, WORKSHOP RECORD LA English DT Proceedings Paper CT IEEE Radiation Effects Data Workshop ( REDW) held in conjunction with the IEEE Nuclear and Space Radiation Effects Conference (NSREC) CY JUL 22, 2004 CL Atlanta, GA SP IEEE Nucl & Plasma Sci Soc, IEEE AB We present data on the vulnerability of a variety of candidate spacecraft electronics to total ionizing dose and displacement damage. Devices tested include optoelectronics, digital, analog, linear bipolar devices, hybrid devices, Analog-to-Digital Converters (ADCs), and Digital-to-Analog Converters (DACs), among others. C1 NASA, Goddard Space Flight Ctr, QSS Grp Inc, Greenbelt, MD USA. RP Cochran, DJ (reprint author), NASA, Goddard Space Flight Ctr, QSS Grp Inc, Code 561-4, Greenbelt, MD USA. NR 12 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-8697-3 PY 2004 BP 19 EP 25 DI 10.1109/REDW.2004.1352898 PG 7 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA BBN14 UT WOS:000226254000004 ER PT B AU Rivas, RM Johnston, AH Miyahira, TF Rax, BG Wiedeman, MD AF Rivas, RM Johnston, AH Miyahira, TF Rax, BG Wiedeman, MD GP ieee TI Test results of Total Ionizing Dose conducted at the Jet Propulsion Laboratory SO 2004 IEEE RADIATION EFFECTS DATA WORKSHOP, WORKSHOP RECORD LA English DT Proceedings Paper CT IEEE Radiation Effects Data Workshop ( REDW) held in conjunction with the IEEE Nuclear and Space Radiation Effects Conference (NSREC) CY JUL 22, 2004 CL Atlanta, GA SP IEEE Nucl & Plasma Sci Soc, IEEE DE bipolar; complementary metal oxide semiconductors (CMOS); enhanced low dose rate sensitivity (ELDRS); high dose level (HDL); low dose level (LDL); and Total Ionizing Dose (TID) ID INTEGRATED-CIRCUITS AB This paper reports recent Total Ionizing Dose (TID) test results obtained at JPL. Several device samples were analyzed exhibiting significant failure levels and ELDRS effects under biased and unbiased condition. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Rivas, RM (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 6 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-8697-3 PY 2004 BP 36 EP 41 DI 10.1109/REDW.2004.1352901 PG 6 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA BBN14 UT WOS:000226254000007 ER PT B AU Poivey, C Gee, G LaBel, KA Barth, JL AF Poivey, C Gee, G LaBel, KA Barth, JL GP ieee TI In-flight observations of long-term Single Event Effect (SEE) performance on X-ray Timing Explorer (XTE) Solid-State Recorders (SSRs) SO 2004 IEEE RADIATION EFFECTS DATA WORKSHOP, WORKSHOP RECORD LA English DT Proceedings Paper CT IEEE Radiation Effects Data Workshop ( REDW) held in conjunction with the IEEE Nuclear and Space Radiation Effects Conference (NSREC) CY JUL 22, 2004 CL Atlanta, GA SP IEEE Nucl & Plasma Sci Soc, IEEE ID SRAMS AB We present multi-year Single Event Upset (SEU) flight data on Solid State Recorder (SSR) memories for the X-ray Timing Explorer (XTE) NASA mission. Actual SEU rates are compared to the predicted rates based on ground test data and environment models. C1 NASA, Goddard Space Flight Ctr, SGT Inc, Greenbelt, MD 20771 USA. RP Poivey, C (reprint author), NASA, Goddard Space Flight Ctr, SGT Inc, Code 561-4, Greenbelt, MD 20771 USA. NR 13 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-8697-3 PY 2004 BP 54 EP 57 DI 10.1109/REDW.2004.1352904 PG 4 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA BBN14 UT WOS:000226254000010 ER PT B AU Langley, TE Murray, P AF Langley, TE Murray, P GP ieee TI SEE and TID test results of 1 Gb Flash memories SO 2004 IEEE RADIATION EFFECTS DATA WORKSHOP, WORKSHOP RECORD LA English DT Proceedings Paper CT IEEE Radiation Effects Data Workshop ( REDW) held in conjunction with the IEEE Nuclear and Space Radiation Effects Conference (NSREC) CY JUL 22, 2004 CL Atlanta, GA SP IEEE Nucl & Plasma Sci Soc, IEEE AB Single-event effects and total ionizing dose test results of 1 Gb FLASH memories are reported in this paper. Effects characterized include single-event upset, latchup and functional interrupt. New effects are discussed and compared with previous results. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Langley, TE (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91125 USA. NR 3 TC 2 Z9 2 U1 0 U2 2 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-8697-3 PY 2004 BP 58 EP 61 DI 10.1109/REDW.2004.1352905 PG 4 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA BBN14 UT WOS:000226254000011 ER PT B AU Guertin, SM Patterson, JD Nguyen, DN AF Guertin, SM Patterson, JD Nguyen, DN GP ieee TI Dynamic SDRAM SEFI detection and recovery test results SO 2004 IEEE RADIATION EFFECTS DATA WORKSHOP, WORKSHOP RECORD LA English DT Proceedings Paper CT IEEE Radiation Effects Data Workshop ( REDW) held in conjunction with the IEEE Nuclear and Space Radiation Effects Conference (NSREC) CY JUL 22, 2004 CL Atlanta, GA SP IEEE Nucl & Plasma Sci Soc, IEEE DE SEFI; SEU; SDRAM; radiation effects AB Single Event Functionality Interrupt (SEFI) results are presented for SDRAMS. SEFI response threshold is below LET 9.9 Mev-cm(2)/mg and saturated cross section is 6x10(-5)cm(2). Dynamic SEFI identification was made, and in-situ recovery restored functionality. Verification results of the identification algorithm are presented. An observed high current radiation response is also presented. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91125 USA. RP Guertin, SM (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91125 USA. NR 6 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-8697-3 PY 2004 BP 62 EP 67 DI 10.1109/REDW.2004.1352906 PG 6 WC Engineering, Electrical & Electronic; Physics, Applied SC Engineering; Physics GA BBN14 UT WOS:000226254000012 ER PT S AU Sherrit, S Badescu, M Bao, X Bar-Cohen, Y Chang, Z AF Sherrit, S Badescu, M Bao, X Bar-Cohen, Y Chang, Z BE Yuhas, MP TI Novel horn designs for power ultrasonics SO 2004 IEEE Ultrasonics Symposium, Vols 1-3 SE ULTRASONICS SYMPOSIUM LA English DT Proceedings Paper CT IEEE Ultrasonics Symposium CY AUG 23-27, 2004 CL Montreal, CANADA SP IEEE Ultrason Ferroelect & Frequency Control Soc DE piezoelectric; ultrasonic horn; drilling; high power AB Ultrasonic horns are used in a variety of industrial and medical applications. At JPL a rock-sampling tool based on an ultrasonic horn was developed to drill, abrade and core rock samples including hard basalts. This device is an impact device, which uses ultrasonic vibrations that occur at the horn tip to produce a sonic resonance with the aid of a loosely connected mass. Although standard horns are found in many current industrial designs they suffer from a few key limitations when used for USDC applications. Manufacturing a horn requires turning down stock material (e.g. Titanium) from the larger outer diameter to the horn tip diameter, and this process is both time consuming and wasteful. In this paper, we present novel horn designs that are specifically designed for impact applications as the USDC. One such design addressed the excessive length that is involved with the use of the horn limiting its applications when system dimensions are constrained. For this purpose, a folded horn design was conceived that reduces the overall length of the resonator (physical length) but maintains or increases the acoustic length. Initial experiments with horns having such a design indicate that the tip displacement can be further adjusted by phasing the bending displacements and the extensional displacements. Another conceived horn design is the "dog bone" horn that uses an end mass on the horn tip to increase the impact efficiency of the horn. In this paper, the experimental results for these novel horn designs are presented and compared to the results predicted by theory. C1 CALTECH, Jet Propuls Lab, Pasadena, CA USA. RP Sherrit, S (reprint author), CALTECH, Jet Propuls Lab, Pasadena, CA USA. NR 6 TC 2 Z9 2 U1 0 U2 2 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1051-0117 BN 0-7803-8413-X J9 ULTRASON PY 2004 BP 2263 EP 2266 PG 4 WC Acoustics; Physics, Applied SC Acoustics; Physics GA BCC37 UT WOS:000228557202172 ER PT S AU Ni, JJ AF Ni, JJ GP IEEE TI On the Chernoff bound for linear-quadratic receivers SO 2004 IEEE WIRELESS COMMUNICATIONS AND NETWORKING CONFERENCE, VOLS 1-4: BROADBAND WIRELESS - THE TIME IS NOW SE IEEE Wireless Communications and Networking Conference LA English DT Proceedings Paper CT IEEE Wireless Communications and Networking Conference CY MAR 21-25, 2004 CL Atlanta, GA SP IEEE DE Chernoff bound; linear-quadratic receiver; CDMA; J-divergence; bhattacharyya distance ID FADING CHANNELS; DETECTORS; COHERENT AB In this paper, we derive the Chernoff bound for linear-quadratic (LQ) receivers and discuss its applications on CDMA fading channels with uncertainty. A detailed derivation of the Chernoff bound is given and other bounds related to the J-divergence and the Bhattacharyya distance are computed and compared to the Chernoff bound. Simulation results verify that the Chernoff bound is more closely related to observed bit error probability even on channels for which the additive noise is not strictly Gaussian, simulations also reveal that the Bhattacharyya distance is potentially a good cost function candidate for receiver design and signal selection. C1 NASA, Johnson Space Ctr, Houston, TX 77058 USA. RP Ni, JJ (reprint author), NASA, Johnson Space Ctr, Houston, TX 77058 USA. NR 12 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1525-3511 BN 0-7803-8344-3 J9 IEEE WCNC PY 2004 BP 83 EP 86 DI 10.1109/WCNC.2004.1311522 PG 4 WC Telecommunications SC Telecommunications GA BAN75 UT WOS:000222999500015 ER PT S AU Qiu, YM Uhl, D Keo, S AF Qiu, YM Uhl, D Keo, S GP IEEE TI 2 mu m InAsSb quantum-dot lasers SO 2004 International Conference on Indium Phosphide and Related Materials, Conference Proceedings SE CONFERENCE PROCEEDINGS - INDIUM PHOSPHIDE AND RELATED MATERIALS LA English DT Proceedings Paper CT 16th International Conference on Indium Phosphide and Related Materials CY MAY 31-JUN 04, 2004 CL Kagoshima, JAPAN SP Japan Soc Appl Phys, IEEE Lasers & Electro Opt Soc, IEEE Electron Devices Soc ID 1.3 MU-M; ROOM-TEMPERATURE; DASH LASERS AB High-density InAsSb quantum dots (QD) have been grown on (001) InP substrates using metalorganic vapor phase epitaxy. Photoluminescence shows the QDs emit light in the range of 1.7-2.2 mu m at room temperature, and at 2 mu m the QDs have luminescence 3 times stronger than that of InAs QDs. Narrow ridge lasers based on a single-stack InAsSb QDs were 2 demonstrated near 2 mu m in cw operation at room temperature with a threshold current density of 730 A/cm(2), output power of 3 mW/facet and a differential quantum efficiency of 13%. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Qiu, YM (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 10 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA SN 1092-8669 BN 0-7803-8595-0 J9 CONF P INDIUM PHOSPH PY 2004 BP 691 EP 694 PG 4 WC Materials Science, Multidisciplinary SC Materials Science GA BBX69 UT WOS:000228291000179 ER PT B AU Barth, JL LaBel, KA Poivey, C AF Barth, JL LaBel, KA Poivey, C GP ieee TI Radiation assurance for the space environment SO 2004 INTERNATIONAL CONFERENCE ON INTEGRATED CIRCUIT DESIGN AND TECHNOLOGY LA English DT Proceedings Paper CT International Conference on Integrated Circuit Design and Technology CY MAY 17-20, 2004 CL Austin, TX SP IEEE Cent TX Sect, Japan Soc Appl Phys ID BIPOLAR LINEAR MICROCIRCUITS; HARDNESS ASSURANCE; INTEGRATED-CIRCUITS; DOSE-RATE; PROTON; ISSUES; UPSET; MICROELECTRONICS; TRANSISTORS; DEGRADATION AB The space radiation environment can lead to extremely harsh operating conditions for spacecraft electronic systems. A hardness assurance methodology must be followed to assure that the space radiation environment does not compromise the functionality and performance of space-based systems during the mission lifetime. The methodology includes a definition of the radiation environment, assessment of the radiation sensitivity of parts, worst-case analysis of the impact of radiation effects, and part acceptance decisions which are likely to include mitigation measures. C1 NASA, Goddard Space Flight Ctr, Flight Data Syst & Radiat Effects Branch, Greenbelt, MD 20771 USA. RP Barth, JL (reprint author), NASA, Goddard Space Flight Ctr, Flight Data Syst & Radiat Effects Branch, Code 561-4, Greenbelt, MD 20771 USA. NR 30 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-8528-4 PY 2004 BP 323 EP 333 DI 10.1109/ICICDT.2004.1309976 PG 11 WC Computer Science, Hardware & Architecture; Engineering, Electrical & Electronic; Materials Science, Multidisciplinary SC Computer Science; Engineering; Materials Science GA BAH90 UT WOS:000222329700055 ER PT B AU Nguyen, TX Koppen, SV Ely, JJ Williams, RA Smith, LJ Salud, MTP AF Nguyen, TX Koppen, SV Ely, JJ Williams, RA Smith, LJ Salud, MTP GP ieee TI Portable wireless device threat assessment for aircraft navigation radios SO 2004 INTERNATIONAL SYMPOSIUM ON ELECTROMAGNETIC COMPATIBILITY, SYMPOSIUM RECORD 1-3 LA English DT Proceedings Paper CT IEEE International Symposium on Electromagnetic Compatibility (EMC 2004) CY AUG 09-13, 2004 CL Santa Clara, CA SP IEEE, EMC Soc, Rohde & Schwarz, AR Worldwide, Compliance Certificat Serv, ETS Lindgren, Murata Elect N A Inc, Sunol Sci, DLS Elect Syst Inc, Int Certificat Serv, Opt Filter, X-EMI DE WLAN; FRS; GMRS spurious emission; aircraft; communication; navigation; interference; 802.11; bluetooth; EMI; reverberation AB This paper addresses the concern for Wireless Local Area Network devices and two-way radios to cause electromagnetic interference to aircraft navigation radio systems. Spurious radiated emissions from various IEEE 802.11a, 802.11b, and Bluetooth devices are characterized using reverberation chambers. The results are compared with baseline emissions from standard laptop computer and personal digital assistants (PDAs) that are currently allowed for use on aircraft. The results indicate that the WLAN devices tested are not more of a threat to aircraft navigation radios than standard laptop computers and PDAs in most aircraft bands. In addition, spurious radiated emission data from seven pairs of two-way radios are provided. These two-way radios emit at much higher levels in the bands considered. A description of the measurement process, device modes of operation and the measurement results are reported. C1 NASA, Langley Res Ctr, Hampton, VA 23665 USA. RP Nguyen, TX (reprint author), NASA, Langley Res Ctr, Hampton, VA 23665 USA. NR 3 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-8443-1 PY 2004 BP 809 EP 814 DI 10.1109/ISEMC.2004.1349926 PG 6 WC Engineering, Electrical & Electronic SC Engineering GA BAU54 UT WOS:000223620100161 ER PT B AU Stoica, A Keymeulen, D Arslan, T Duong, V Zebulum, R Ferguson, I Guo, X AF Stoica, A Keymeulen, D Arslan, T Duong, V Zebulum, R Ferguson, I Guo, X BE Zebulum, RS Gwaltney, D Hornby, G Keymeulen, D Lohn, F Stoica, A TI Circuit self-recovery experiments in extreme environments SO 2004 NASA/DOD CONFERENCE ON EVOLVABLE HARDWARE, PROCEEDINGS LA English DT Proceedings Paper CT 6th NASA/DoD Conference on Evolvable Hardware CY JUN 24-26, 2004 CL Jet Propuls Lab, Seattle, WA SP NASA, US Dept Def, IEEE Circuits & Syst Soc HO Jet Propuls Lab AB Temperature and radiation tolerant electronics, as well as long life survivability are key capabilities required for future NASA missions. Current approaches to electronics for extreme environments focus on component level robustness and hardening. However, current technology can only ensure very limited lifetime in extreme environments. This paper describes novel experiments that allow adaptive in-situ circuit redesign/reconfiguration in extreme temperature and radiation environments. This technology would complement material/device/layout advancements and increase the mission capability to survive harsh environments. The approach is demonstrated on a mixed-signal programmable chip (FPTA-2), which recovers functionality for temperatures reaching 280degreesC and with total radiation dose up to 175kRad C1 Jet Prop Lab, Pasadena, CA 91109 USA. RP Stoica, A (reprint author), Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 2 TC 0 Z9 1 U1 0 U2 0 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 USA BN 0-7695-2145-2 PY 2004 BP 142 EP 145 PG 4 WC Computer Science, Hardware & Architecture SC Computer Science GA BAN41 UT WOS:000222965600021 ER PT B AU Bar-Cohen, Y AF Bar-Cohen, Y BE Zebulum, RS Gwaltney, D Hornby, G Keymeulen, D Lohn, F Stoica, A TI Electroactive Polymers (EAP) as actuators for potential future planetary mechanisms SO 2004 NASA/DOD CONFERENCE ON EVOLVABLE HARDWARE, PROCEEDINGS LA English DT Proceedings Paper CT 6th NASA/DoD Conference on Evolvable Hardware CY JUN 24-26, 2004 CL Jet Propuls Lab, Seattle, WA SP NASA, US Dept Def, IEEE Circuits & Syst Soc HO Jet Propuls Lab AB In the last fifteen years a series of Electroactive Polymers (EAP) materials have emerged that exhibit a significant shape or size change in response to electrical stimulation. These materials have the closest response similarity to biological muscles enabling to engineer novel capabilities that were considered until recently science fiction ideas. Initially, EAP received relatively little attention due to their limited actuation capability. Recent progress led to dramatic improvements in the capability of these materials and efforts are underway to address the many challenges that are hampering the practical application of these materials. Various novel mechanisms and devices were already demonstrated including robot fish, catheter steering element, robotic arm, gripper, loudspeaker, active diaphragm, and dust-wiper. For developers of future planetary mechanisms the flexibility, fracture toughness, low mass and low power requirements of these materials are offering numerous advantages. This paper provides background about these materials and it includes a review of the state of the art, challenges and potential applications of these materials for future space missions. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Bar-Cohen, Y (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr,M-S 82-105, Pasadena, CA 91109 USA. NR 11 TC 1 Z9 1 U1 0 U2 3 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 USA BN 0-7695-2145-2 PY 2004 BP 309 EP 317 PG 9 WC Computer Science, Hardware & Architecture SC Computer Science GA BAN41 UT WOS:000222965600043 ER PT B AU Millis, MG AF Millis, MG BE Zebulum, RS Gwaltney, D Hornby, G Keymeulen, D Lohn, F Stoica, A TI Prospects for breakthrough propulsion from physics SO 2004 NASA/DOD CONFERENCE ON EVOLVABLE HARDWARE, PROCEEDINGS LA English DT Proceedings Paper CT 6th NASA/DoD Conference on Evolvable Hardware CY JUN 24-26, 2004 CL Jet Propuls Lab, Seattle, WA SP NASA, US Dept Def, IEEE Circuits & Syst Soc HO Jet Propuls Lab ID ZERO-POINT-FIELD; DEEP DIRAC LEVELS; GENERAL-RELATIVITY; CASIMIR FORCES; WARP DRIVE; ELECTRON TRANSITIONS; VACUUM; ENERGY; FLUCTUATIONS; WORMHOLES AB "Space drives," "Warp drives," and "Wormholes:" these concepts may sound like science fiction, but they are being written about in reputable journals. To assess the implications of these emerging prospects for future spaceflight, NASA supported the Breakthrough Propulsion Physics Project from 1996 through 2002. This Project has three grand challenges: (1) Discover propulsion that eliminates the need for propellant; (2) Discover methods to achieve hyper-fast travel; and (3) Discover breakthrough methods to power spacecraft. Because these challenges are presumably far from fruition, and perhaps even impossible, a special emphasis is placed on selecting incremental and affordable research that addresses the critical issues behind these challenges. Of 16 incremental research tasks completed by the Project and from other sponsors, about a third were found not to be viable, a quarter have clear opportunities for sequels, and the rest remain unresolved. C1 NASA, Glenn Res Ctr, Cleveland, OH 44145 USA. RP NASA, Glenn Res Ctr, Cleveland, OH 44145 USA. EM marc.g.millis@nasa.gov NR 94 TC 0 Z9 0 U1 0 U2 3 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 USA BN 0-7695-2145-2 PY 2004 BP 325 EP 333 PG 9 WC Computer Science, Hardware & Architecture SC Computer Science GA BAN41 UT WOS:000222965600045 ER PT B AU Sims, WH Pearson, JB AF Sims, WH Pearson, JB BE Zebulum, RS Gwaltney, D Hornby, G Keymeulen, D Lohn, F Stoica, A TI Radio frequency (RF) trap for confinement of ion plasmas in antimatter propulsion systems using rotating wall electric fields SO 2004 NASA/DOD CONFERENCE ON EVOLVABLE HARDWARE, PROCEEDINGS LA English DT Proceedings Paper CT 6th NASA/DoD Conference on Evolvable Hardware CY JUN 24-26, 2004 CL Jet Propuls Lab, Seattle, WA SP NASA, US Dept Def, IEEE Circuits & Syst Soc HO Jet Propuls Lab AB Perturbations associated with a rotating wall electric field enable the confinement of ions for periods approaching weeks. This steady state confinement is a result of a radio frequency manipulation of the ions. Using state-of-the-art techniques it is shown that radio frequency energy can produce useable manipulation of the ion cloud (matter or antimatter) for use in containment experiments. The current research focuses on the improvement of confinement systems capable of containing and transporting antimatter. C1 NASA, George C Marshall Space Flight Ctr, Huntsville, AL 35812 USA. RP Sims, WH (reprint author), NASA, George C Marshall Space Flight Ctr, Bldg 4566-TD40A,MSFC, Huntsville, AL 35812 USA. NR 3 TC 0 Z9 0 U1 0 U2 1 PU IEEE COMPUTER SOC PI LOS ALAMITOS PA 10662 LOS VAQUEROS CIRCLE, PO BOX 3014, LOS ALAMITOS, CA 90720-1264 USA BN 0-7695-2145-2 PY 2004 BP 334 EP 339 PG 6 WC Computer Science, Hardware & Architecture SC Computer Science GA BAN41 UT WOS:000222965600046 ER PT B AU Chao, TH Hanan, J Reyes, G Zhou, HY AF Chao, TH Hanan, J Reyes, G Zhou, HY GP ieee TI Compact digital holographic memory SO 2004 NON-VOLATILE MEMORY TECHNOLOGY SYMPOSIUM, PROCEEDINGS LA English DT Proceedings Paper CT 5th Annual Non-Volatile Memory Technology Symposium CY NOV 15-17, 2004 CL Orlando, FL SP NASA, USAF Res Lab, Def Threat Reduct Agcy, IEEE Aerosp & Elect Syst Soc, IEEE Electron Devices Soc AB Recent technical progress in developing a compact digital holographic memory system is presented. Due to rapid advancement in data input and output devices, electro-optic beam steering technology, and diode laser source, a compact holographic memory brassboard for digital data storage has been integrated. The system consist of a 1 Meg pixel binary spatial light modulator, a PI beam steering mirror, a CMOS photo sensor, a LiNbO3 photorefractive crystal, and a blue laser source. The system architecture and experimental test data will be discussed. An overview of the holographic data storage technology will also be discussed. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP Chao, TH (reprint author), CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA. NR 10 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-8726-0 PY 2004 BP 5 EP 9 DI 10.1109/NVMT.2004.1380791 PG 5 WC Computer Science, Hardware & Architecture SC Computer Science GA BBK55 UT WOS:000225881700001 ER PT B AU Clark, K AF Clark, K GP ieee TI The Jupiter icy moons orbiter mission: A challenging search for life SO 2004 NON-VOLATILE MEMORY TECHNOLOGY SYMPOSIUM, PROCEEDINGS LA English DT Proceedings Paper CT 5th Annual Non-Volatile Memory Technology Symposium CY NOV 15-17, 2004 CL Orlando, FL SP NASA, USAF Res Lab, Def Threat Reduct Agcy, IEEE Aerosp & Elect Syst Soc, IEEE Electron Devices Soc C1 Jet Prop Lab, Pasadena, CA USA. RP Clark, K (reprint author), Jet Prop Lab, Pasadena, CA USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-8726-0 PY 2004 BP 155 EP 155 DI 10.1109/NVMT.2004.1380834 PG 1 WC Computer Science, Hardware & Architecture SC Computer Science GA BBK55 UT WOS:000225881700029 ER PT B AU Chen, Y Wang, Q Kayali, S AF Chen, Y Wang, Q Kayali, S GP JEDEC TI A statistical approach to characterizing the reliability of systems utilizing HBT devices SO 2004 ROCS WORKSHOP - RELIABILITY OF COMPOUND SEMICONDUCTORS, PROCEEDINGS LA English DT Proceedings Paper CT Workshop on Reliability of Compound Semiconductors (ROCS) CY OCT 24, 2004 CL Monterey, CA SP JEDEC JC 14 7, IEEE Electron Devices Soc ID THERMAL-RESISTANCE; JUNCTION TEMPERATURE AB As users of hetero bipolar transistors (HBTs), we have built systems with quite a few HBT devices on critical paths. There has been extensive research on individual HBTs regarding performance, reliability, and failure mechanisms. However, the evaluation and assessment of the system-level reliability of the HBT systems is also of great importance. To determine system-level reliability, the worst-case approach is typically used. This practice is to equate the life of the HBT device(s) under the worst bias condition(s) to the life of the system. However, because of the statistical nature of the life of the individual HBTs, this worst-case practice does not necessarily provide the life of the weakest link in the system. C1 CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. RP CALTECH, Jet Prop Lab, Pasadena, CA 91109 USA. EM yuan.chen@jpl.nasa.gov NR 16 TC 0 Z9 0 U1 0 U2 0 PU JEDEC PI ARLINGTON PA 2500 WILSON BLVD, ARLINGTON, VA 22201 USA BN 0-7908-0105-1 PY 2004 BP 3 EP 7 PG 5 WC Engineering, Electrical & Electronic; Materials Science, Multidisciplinary; Materials Science, Characterization & Testing; Physics, Condensed Matter SC Engineering; Materials Science; Physics GA BBV53 UT WOS:000228030700001 ER PT B AU Alterovitz, SA Ponchak, GE Mueller, CH Croke, ET AF Alterovitz, SA Ponchak, GE Mueller, CH Croke, ET BE Cressler, JD Papapolymerou, J TI High mobility SiGe/Si n-type structures and field effect transistors on sapphire substrates SO 2004 TOPICAL MEETING ON SILICON MONOLITHIC INTEGRATED CIRCUITS IN RF SYSTEMS, DIGEST OF PAPERS LA English DT Proceedings Paper CT Topical Meeting on Silicon Monolithic Intergrated Circuits in RF Systems CY SEP 08-10, 2004 CL Atlanta, GA SP IEEE Microwave Theory & Tech Soc, Geirgua Tech, Georgia Electronic Design Ctr, NASA Glenn Res Ctr DE SiGe; MODFET; sapphire ID HIGH-ELECTRON-MOBILITY; TECHNOLOGY; MODFET; CMOS; GHZ AB SiGe/Si n-type modulation doped field effect transistors (MODFETs) fabricated on sapphire substrates are characterized at microwave frequencies for the first time. The highest measured room temperature electron mobility is 1380 cm(2)/ V-sec at a carrier density of 1.8 x 10(12) cm(-2) for a MODFET structure. At room temperature, a two finger, 2 x 200 micron gate n-MODFET has a peak transconductance of 37 mS/mm at a drain to source voltage of 2.5 V and an f(max) of 2.45 GHz. Microwave performance of the transistor improved with decreasing temperatures, with an f(max)=5.25 GHz at 100K. C1 NASA, Glenn Res Ctr, Cleveland, OH 44135 USA. RP NASA, Glenn Res Ctr, 21000 Brookpk Rd, Cleveland, OH 44135 USA. EM Samuel.A.Alterovitz@grc.nasa.gov NR 18 TC 0 Z9 0 U1 0 U2 0 PU IEEE PI NEW YORK PA 345 E 47TH ST, NEW YORK, NY 10017 USA BN 0-7803-8703-1 PY 2004 BP 107 EP 110 PG 4 WC Engineering, Electrical & Electronic SC Engineering GA BBW01 UT WOS:000228081500028 ER PT S AU Einaudi, F Schwemmer, GK Gentry, BM Abshire, JB AF Einaudi, F Schwemmer, GK Gentry, BM Abshire, JB BE Pappalardo, G Amodeo, A TI Lidar past, present, and future in NASA'S earth and space science programs SO 22ND INTERNATIONAL LASER RADAR CONFERENCE (ILRC 2004), VOLS 1 AND 2 SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 22nd International Laser Radar Conference (ILRC 2004) CY JUL 12-16, 2004 CL Matera, ITALY SP ICLAS, Int Coordinat Grp Laser Atmospher Studies, Ist Metodol Analisi Ambientale, Consiglio Nazl Ric, esa, NASA AB Lidar is firmly entrenched in the family of remote sensing technologies that NASA is developing and using. Still a relatively new technology, lidar should continue to experience significant advances and progress. Lidar is used in each one of the major research themes, including planetary exploration, in the Earth Sciences Directorate at Goddard Space Flight Center. NASA has and will continue to generate new lidar applications from ground, air and space for both Earth science and planetary exploration. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Einaudi, F (reprint author), NASA, Goddard Space Flight Ctr, Code 900, Greenbelt, MD 20771 USA. RI Abshire, James/I-2800-2013 NR 0 TC 0 Z9 0 U1 0 U2 0 PU ESA PUBLICATIONS DIVISION C/O ESTEC PI 2200 AG NOORDWIJK PA PO BOX 299, 2200 AG NOORDWIJK, NETHERLANDS SN 0379-6566 BN 92-9092-872-7 J9 ESA SP PUBL PY 2004 VL 561 BP 7 EP 10 PG 4 WC Instruments & Instrumentation; Meteorology & Atmospheric Sciences; Remote Sensing; Optics SC Instruments & Instrumentation; Meteorology & Atmospheric Sciences; Remote Sensing; Optics GA BAP51 UT WOS:000223133500002 ER PT S AU Schwemmer, GK Miller, DO Wilkerson, TD Lee, SW AF Schwemmer, GK Miller, DO Wilkerson, TD Lee, SW BE Pappalardo, G Amodeo, A TI Lidar data products and applications enabled by conical scanning SO 22ND INTERNATIONAL LASER RADAR CONFERENCE (ILRC 2004), VOLS 1 AND 2 SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 22nd International Laser Radar Conference (ILRC 2004) CY JUL 12-16, 2004 CL Matera, ITALY SP ICLAS, Int Coordinat Grp Laser Atmospher Studies, Ist Metodol Analisi Ambientale, Consiglio Nazl Ric, esa, NASA AB Several new data products and applications for elastic backscatter lidar are achieved using simple conical scanning. Atmospheric boundary layer spatial and temporal structure is revealed with resolution not possible with static pointing lidars. Cloud fractional coverage as a function of altitude is possible with high temporal resolution. Wind profiles are retrieved from the cloud and aerosol structure motions revealed by scanning. New holographic technology will soon allow quasi-conical scanning and push-broom lidar imaging without mechanical scanning. C1 NASA, Greenbelt, MD 20771 USA. RP Schwemmer, GK (reprint author), NASA, Code 912, Greenbelt, MD 20771 USA. NR 5 TC 1 Z9 1 U1 0 U2 0 PU ESA PUBLICATIONS DIVISION C/O ESTEC PI 2200 AG NOORDWIJK PA PO BOX 299, 2200 AG NOORDWIJK, NETHERLANDS SN 0379-6566 BN 92-9092-872-7 J9 ESA SP PUBL PY 2004 VL 561 BP 17 EP 20 PG 4 WC Instruments & Instrumentation; Meteorology & Atmospheric Sciences; Remote Sensing; Optics SC Instruments & Instrumentation; Meteorology & Atmospheric Sciences; Remote Sensing; Optics GA BAP51 UT WOS:000223133500004 ER PT S AU Singh, UN Kavaya, MJ AF Singh, UN Kavaya, MJ BE Pappalardo, G Amodeo, A TI Overview and accomplishments of NASA's laser risk reduction program at NASA langley research center SO 22ND INTERNATIONAL LASER RADAR CONFERENCE (ILRC 2004), VOLS 1 AND 2 SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 22nd International Laser Radar Conference (ILRC 2004) CY JUL 12-16, 2004 CL Matera, ITALY SP ICLAS, Int Coordinat Grp Laser Atmospher Studies, Ist Metodol Analisi Ambientale, Consiglio Nazl Ric, esa, NASA AB Peer review of NASA's space-based lidar missions and of the technology readiness of lasers appropriate for space-based lidars, conducted in September 2000, indicated a critical need for an integrated research and development strategy, which combines technologies from government, industry, and university towards advancing solid laser transmitter technology from low technical readiness levels to higher levels required for space missions. A multi-Center NASA team formulated an integrated NASA strategy to provide the technology and maturity of systems necessary to make Lidar/Laser systems viable for space-based study and monitoring of the earth's atmosphere. This paper gives the overview of the NASA's Laser Risk Reduction Program (LRRP) and describes the progress made at NASA Langley Research Center towards advancing the laser technologies for space-based remote sensing of the earth's atmosphere. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Singh, UN (reprint author), NASA, Langley Res Ctr, MS 433,5N Dryden St, Hampton, VA 23681 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ESA PUBLICATIONS DIVISION C/O ESTEC PI 2200 AG NOORDWIJK PA PO BOX 299, 2200 AG NOORDWIJK, NETHERLANDS SN 0379-6566 BN 92-9092-872-7 J9 ESA SP PUBL PY 2004 VL 561 BP 49 EP 52 PG 4 WC Instruments & Instrumentation; Meteorology & Atmospheric Sciences; Remote Sensing; Optics SC Instruments & Instrumentation; Meteorology & Atmospheric Sciences; Remote Sensing; Optics GA BAP51 UT WOS:000223133500012 ER PT S AU Ismail, S Koch, GJ Barnes, BW Abedin, N Refaat, TF Yu, JR Vay, SA Kooi, SA Browell, EV Singh, UN AF Ismail, S Koch, GJ Barnes, BW Abedin, N Refaat, TF Yu, JR Vay, SA Kooi, SA Browell, EV Singh, UN BE Pappalardo, G Amodeo, A TI Technology developments for tropospheric profiling of CO2 and ground-based measurements SO 22ND INTERNATIONAL LASER RADAR CONFERENCE (ILRC 2004), VOLS 1 AND 2 SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 22nd International Laser Radar Conference (ILRC 2004) CY JUL 12-16, 2004 CL Matera, ITALY SP ICLAS, Int Coordinat Grp Laser Atmospher Studies, Ist Metodol Analisi Ambientale, Consiglio Nazl Ric, esa, NASA ID TM-YLF LASER; CARBON-DIOXIDE; AIRBORNE AB Significant technology developments are progressing in the areas of lasers, detectors, and receiver systems to enable tropospheric CO2 profiling capability needed to understand global carbon cycle processes. High precision measurements are required to understand the variability of atmospheric CO2 and to evaluate the influence of sources and sinks Of CO2. A review of recent technology developments is presented including new developments in lasers and new high efficiency, relatively low noise detectors at 2 mum wavelength region. A ground-based heterodyne differential absorption lidar (DIAL) was used to observe the diurnal variability of CO, in the lower troposphere. In situ CO2 measurements via a Li-Cor NDIR spectrometer were compared with the observations of the ground-based DIAL system to evaluate its sensitivity. A Measurement precision of 1.5% standard deviation was estimated for the DIAL measurements of the ground-based DIAL system. Capability of a shot-noise limited ground-based direct detection DIAL system using a novel 2 mum phototransitor and a large collection area receiver for tropospheric profiling Of CO2 is investigated. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Ismail, S (reprint author), NASA, Langley Res Ctr, Hampton, VA 23681 USA. NR 13 TC 0 Z9 0 U1 0 U2 0 PU ESA PUBLICATIONS DIVISION C/O ESTEC PI 2200 AG NOORDWIJK PA PO BOX 299, 2200 AG NOORDWIJK, NETHERLANDS SN 0379-6566 BN 92-9092-872-7 J9 ESA SP PUBL PY 2004 VL 561 BP 65 EP 68 PG 4 WC Instruments & Instrumentation; Meteorology & Atmospheric Sciences; Remote Sensing; Optics SC Instruments & Instrumentation; Meteorology & Atmospheric Sciences; Remote Sensing; Optics GA BAP51 UT WOS:000223133500016 ER PT S AU Burris, J Richter, D AF Burris, J Richter, D BE Pappalardo, G Amodeo, A TI An optical parametric amplifier for profiling gases of atmospheric interest SO 22ND INTERNATIONAL LASER RADAR CONFERENCE (ILRC 2004), VOLS 1 AND 2 SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 22nd International Laser Radar Conference (ILRC 2004) CY JUL 12-16, 2004 CL Matera, ITALY SP ICLAS, Int Coordinat Grp Laser Atmospher Studies, Ist Metodol Analisi Ambientale, Consiglio Nazl Ric, esa, NASA AB This paper describes the development of a lidar transmitter using an optical parametric amplifier. It is designed for profiling gases of atmospheric interest at high spatial and temporal precision in the near-IR. Discussions on desirable characteristics for such a transmitter with specific reference to the case of CO2 are made. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Burris, J (reprint author), NASA, Goddard Space Flight Ctr, Code 916, Greenbelt, MD 20771 USA. NR 3 TC 0 Z9 0 U1 0 U2 0 PU ESA PUBLICATIONS DIVISION C/O ESTEC PI 2200 AG NOORDWIJK PA PO BOX 299, 2200 AG NOORDWIJK, NETHERLANDS SN 0379-6566 BN 92-9092-872-7 J9 ESA SP PUBL PY 2004 VL 561 BP 187 EP 189 PG 3 WC Instruments & Instrumentation; Meteorology & Atmospheric Sciences; Remote Sensing; Optics SC Instruments & Instrumentation; Meteorology & Atmospheric Sciences; Remote Sensing; Optics GA BAP51 UT WOS:000223133500046 ER PT S AU Yu, JR Lee, HR Bai, YX Barnes, NP AF Yu, JR Lee, HR Bai, YX Barnes, NP BE Pappalardo, G Amodeo, A TI Tunable 4-10 mu m infrared radiation for remote sensing applications SO 22ND INTERNATIONAL LASER RADAR CONFERENCE (ILRC 2004), VOLS 1 AND 2 SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 22nd International Laser Radar Conference (ILRC 2004) CY JUL 12-16, 2004 CL Matera, ITALY SP ICLAS, Int Coordinat Grp Laser Atmospher Studies, Ist Metodol Analisi Ambientale, Consiglio Nazl Ric, esa, NASA AB A high energy and tunable mid-IR laser source has been developed. This system consists of two major components; a high-energy 2.05-micron pump laser and a parametric oscillator tunable between 4 to 10 microns. The 2-micron laser with high beam quality and narrow linewidth feature makes it a superior pump source for the parametric oscillator. Recent significant material growth improvement of Zinc Germanium Phosphide produces the crystal with sufficient low absorption at the 2.05 pump wavelength (<0.1cm(-1)). This crystal also has the characteristics of wide transparency range and large second-order nonlinearities. We report a singly resonant, 2.05 mum pumped Zinc Germanium Phosphide optical parametric oscillator with high pulse energy output at an energy conversion efficiency of 27.5%. It generates up to 17.3mJ with the tunability over 4.3-10.1mum-wavelength range. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Yu, JR (reprint author), NASA, Langley Res Ctr, MS 468, Hampton, VA 23681 USA. NR 9 TC 0 Z9 0 U1 0 U2 1 PU ESA PUBLICATIONS DIVISION C/O ESTEC PI 2200 AG NOORDWIJK PA PO BOX 299, 2200 AG NOORDWIJK, NETHERLANDS SN 0379-6566 BN 92-9092-872-7 J9 ESA SP PUBL PY 2004 VL 561 BP 195 EP 197 PG 3 WC Instruments & Instrumentation; Meteorology & Atmospheric Sciences; Remote Sensing; Optics SC Instruments & Instrumentation; Meteorology & Atmospheric Sciences; Remote Sensing; Optics GA BAP51 UT WOS:000223133500048 ER PT S AU Heaps, WS Novo-Gradac, AM AF Heaps, WS Novo-Gradac, AM BE Pappalardo, G Amodeo, A TI Progress on space borne laser risk reduction at Goddard Space Flight Center SO 22ND INTERNATIONAL LASER RADAR CONFERENCE (ILRC 2004), VOLS 1 AND 2 SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 22nd International Laser Radar Conference (ILRC 2004) CY JUL 12-16, 2004 CL Matera, ITALY SP ICLAS, Int Coordinat Grp Laser Atmospher Studies, Ist Metodol Analisi Ambientale, Consiglio Nazl Ric, esa, NASA AB At the direction of NASA Headquarters NASA Goddard Space Flight Center (GSFC) and NASA Langley Research Center (LaRC) undertook in 2002 a program in fundamental research on laser manufacturing technologies aimed at improving the performance and lifetime of lasers sent into space for remote sensing applications. The work at GSFC has concentrated on three areas: 1) development of high power 1 mu lasers, 2) lifetime and reliability testing for 808 nm pump diodes, and 3) efficient conversion of 1 mu radiation to wavelengths needed for various remote sensing tasks. After almost 2 years of development interesting results in all three areas are beginning to emerge. Some of these results will be described along with discussion of future directions. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Heaps, WS (reprint author), NASA, Goddard Space Flight Ctr, Code 554, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 0 PU ESA PUBLICATIONS DIVISION C/O ESTEC PI 2200 AG NOORDWIJK PA PO BOX 299, 2200 AG NOORDWIJK, NETHERLANDS SN 0379-6566 BN 92-9092-872-7 J9 ESA SP PUBL PY 2004 VL 561 BP 207 EP 209 PG 3 WC Instruments & Instrumentation; Meteorology & Atmospheric Sciences; Remote Sensing; Optics SC Instruments & Instrumentation; Meteorology & Atmospheric Sciences; Remote Sensing; Optics GA BAP51 UT WOS:000223133500051 ER PT S AU Krainak, MA Andrews, AE Allan, G Burris, JF Collatz, GJ Riris, H Sun, XL Gates, A Abshire, JB AF Krainak, MA Andrews, AE Allan, G Burris, JF Collatz, GJ Riris, H Sun, XL Gates, A Abshire, JB BE Pappalardo, G Amodeo, A TI Laser sounder for measuring atmospheric CO2 from orbit SO 22ND INTERNATIONAL LASER RADAR CONFERENCE (ILRC 2004), VOLS 1 AND 2 SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 22nd International Laser Radar Conference (ILRC 2004) CY JUL 12-16, 2004 CL Matera, ITALY SP ICLAS, Int Coordinat Grp Laser Atmospher Studies, Ist Metodol Analisi Ambientale, Consiglio Nazl Ric, esa, NASA AB We describe progress in developing a laser-based approach for the remote measurement of atmospheric CO2 from a satellite in low earth orbit. In this method, CO2 abundance is measured by differential absorption in an overtone band near 1.57 mum. The dry-air mixing ratio can be calculated from the ratio of CO2 to O-2, which can be measured using a similar technique applied to an O-2 absorption at 770 nm. A third channel operating at 1.064 mum will be used for cloud and aerosol detection. The approach leverages technology development by the telecommunications industry, using mainly commercially available components, many of which have already been space qualified. Measurement precision better than 1% will be needed to satisfy the scientific requirements. Component stability and noise levels must therefore be thoroughly investigated. In addition, a rigorous calibration strategy will be required. We report initial atmospheric measurements over a horizontal path and results from tests to characterize individual components. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Krainak, MA (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RI Sun, Xiaoli/B-5120-2013; Riris, Haris/D-1004-2013; Abshire, James/I-2800-2013; Allan, Graham/D-3905-2013; Andrews, Arlyn/K-3427-2012 NR 13 TC 0 Z9 0 U1 0 U2 0 PU ESA PUBLICATIONS DIVISION C/O ESTEC PI 2200 AG NOORDWIJK PA PO BOX 299, 2200 AG NOORDWIJK, NETHERLANDS SN 0379-6566 BN 92-9092-872-7 J9 ESA SP PUBL PY 2004 VL 561 BP 211 EP 214 PG 4 WC Instruments & Instrumentation; Meteorology & Atmospheric Sciences; Remote Sensing; Optics SC Instruments & Instrumentation; Meteorology & Atmospheric Sciences; Remote Sensing; Optics GA BAP51 UT WOS:000223133500052 ER PT S AU Stephen, MA Vasilyev, A Schafer, J Allan, GR AF Stephen, MA Vasilyev, A Schafer, J Allan, GR BE Pappalardo, G Amodeo, A TI Qualification of laser diode arrays for mercury laser altimeter SO 22ND INTERNATIONAL LASER RADAR CONFERENCE (ILRC 2004), VOLS 1 AND 2 SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 22nd International Laser Radar Conference (ILRC 2004) CY JUL 12-16, 2004 CL Matera, ITALY SP ICLAS, Int Coordinat Grp Laser Atmospher Studies, Ist Metodol Analisi Ambientale, Consiglio Nazl Ric, esa, NASA AB NASA's requirements for high reliability, high performance satellite laser instruments have driven the investigation of many critical components; specifically, 808 nm laser diode array (LDA) pump devices. Performance of Quasi-CW, High-power, laser diode arrays under extended use is presented. We report the optical power over several hundred million pulse operation and the effect of power cycling and temperature cycling of the laser diode arrays. Data on the initial characterization of the devices is also presented. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Stephen, MA (reprint author), NASA, Goddard Space Flight Ctr, Mail Code 924, Greenbelt, MD 20771 USA. RI Allan, Graham/D-3905-2013 NR 3 TC 0 Z9 0 U1 0 U2 0 PU ESA PUBLICATIONS DIVISION C/O ESTEC PI 2200 AG NOORDWIJK PA PO BOX 299, 2200 AG NOORDWIJK, NETHERLANDS SN 0379-6566 BN 92-9092-872-7 J9 ESA SP PUBL PY 2004 VL 561 BP 215 EP 218 PG 4 WC Instruments & Instrumentation; Meteorology & Atmospheric Sciences; Remote Sensing; Optics SC Instruments & Instrumentation; Meteorology & Atmospheric Sciences; Remote Sensing; Optics GA BAP51 UT WOS:000223133500053 ER PT S AU Vann, LB De Young, R Mihailov, S AF Vann, LB De Young, R Mihailov, S BE Pappalardo, G Amodeo, A TI Ultra-narrow band fiberoptic Bragg grating filters for atmospheric water vapor measurements SO 22ND INTERNATIONAL LASER RADAR CONFERENCE (ILRC 2004), VOLS 1 AND 2 SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 22nd International Laser Radar Conference (ILRC 2004) CY JUL 12-16, 2004 CL Matera, ITALY SP ICLAS, Int Coordinat Grp Laser Atmospher Studies, Ist Metodol Analisi Ambientale, Consiglio Nazl Ric, esa, NASA AB Experimental results using ultra-narrow band fiberoptic Bragg grating filters for DIAL atmospheric water vapor measurements are presented. Special fiber Bragg gratings were fabricated by Communications Research Center that had a 2.66-nm stop band centered at 946 nm; within this stop band were two transmission filter peaks: one peak at a 946.0003-nm water vapor absorption line and another peak at 945.9 nm, a region of no absorption. Experimental demonstration of pressure filter tuning was achieved and the performance characterization of several custom-made optical fiber Bragg grating filters was made. These measurements were compared with a theoretical model using a piecewise matrix form of the coupled-mode equation. C1 NASA Langley Res Ctr, Hampton, VA 23681 USA. RP De Young, R (reprint author), NASA Langley Res Ctr, Hampton, VA 23681 USA. NR 9 TC 0 Z9 0 U1 0 U2 0 PU ESA PUBLICATIONS DIVISION C/O ESTEC PI 2200 AG NOORDWIJK PA PO BOX 299, 2200 AG NOORDWIJK, NETHERLANDS SN 0379-6566 BN 92-9092-872-7 J9 ESA SP PUBL PY 2004 VL 561 BP 231 EP 234 PG 4 WC Instruments & Instrumentation; Meteorology & Atmospheric Sciences; Remote Sensing; Optics SC Instruments & Instrumentation; Meteorology & Atmospheric Sciences; Remote Sensing; Optics GA BAP51 UT WOS:000223133500057 ER PT S AU Ferrare, R Turner, D Clayton, M Brackett, V Schmid, B Redemann, J Covert, D Elleman, R Ogren, J Andrews, E Goldsmith, J Jonsson, H Brooks, I AF Ferrare, R Turner, D Clayton, M Brackett, V Schmid, B Redemann, J Covert, D Elleman, R Ogren, J Andrews, E Goldsmith, J Jonsson, H Brooks, I BE Pappalardo, G Amodeo, A TI Raman lidar measurements of aerosols and water vapor over the Southern Great Plains SO 22ND INTERNATIONAL LASER RADAR CONFERENCE (ILRC 2004), VOLS 1 AND 2 SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 22nd International Laser Radar Conference (ILRC 2004) CY JUL 12-16, 2004 CL Matera, ITALY SP ICLAS, Int Coordinat Grp Laser Atmospher Studies, Ist Metodol Analisi Ambientale, Consiglio Nazl Ric, esa, NASA ID PROFILES AB Raman lidar water vapor and aerosol extinction profiles acquired over the Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Southern Great Plains (SGP) site in northern Oklahoma (36.606 N, 97.50 W) are evaluated using profiles measured by ground-based and airborne in situ and remote sensing instruments deployed during the May 2003 Aerosol Intensive Operations Period (IOP). The Raman lidar water vapor (aerosol extinction) measurements were, on average, 0-15% (30-50%) higher than the other measurements. The high bias of the Raman lidar aerosol extinction measurements is due primarily to several issues associated with a general loss of sensitivity of the Raman lidar since early 2002. When used in combination with backtrajectory analyses, Raman lidar water vapor and aerosol extinction measurements acquired during 2000 and 2001 show that the vertical profiles of water vapor and aerosol extinction vary with these air mass transport patterns and with aerosol optical thickness and precipitable water vapor. The variabilities of the planetary boundary layer (PBL) height and transition zone thickness are also examined using the lidar water vapor and aerosol profiles. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Ferrare, R (reprint author), NASA, Langley Res Ctr, MS 401A, Hampton, VA 23681 USA. OI Brooks, Ian/0000-0002-5051-1322; Ogren, John/0000-0002-7895-9583 NR 8 TC 1 Z9 1 U1 0 U2 0 PU ESA PUBLICATIONS DIVISION C/O ESTEC PI 2200 AG NOORDWIJK PA PO BOX 299, 2200 AG NOORDWIJK, NETHERLANDS SN 0379-6566 BN 92-9092-872-7 J9 ESA SP PUBL PY 2004 VL 561 BP 333 EP 336 PG 4 WC Instruments & Instrumentation; Meteorology & Atmospheric Sciences; Remote Sensing; Optics SC Instruments & Instrumentation; Meteorology & Atmospheric Sciences; Remote Sensing; Optics GA BAP51 UT WOS:000223133500082 ER PT S AU Whiteman, DN Demoz, B Di Girolamo, P Comer, J Wang, Z Lin, RF Evans, K Veselovskii, I AF Whiteman, DN Demoz, B Di Girolamo, P Comer, J Wang, Z Lin, RF Evans, K Veselovskii, I BE Pappalardo, G Amodeo, A TI NASA/GSFC scanning Raman lidar measurements of water vapor and clouds during IHOP SO 22ND INTERNATIONAL LASER RADAR CONFERENCE (ILRC 2004), VOLS 1 AND 2 SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 22nd International Laser Radar Conference (ILRC 2004) CY JUL 12-16, 2004 CL Matera, ITALY SP ICLAS, Int Coordinat Grp Laser Atmospher Studies, Ist Metodol Analisi Ambientale, Consiglio Nazl Ric, esa, NASA AB The NASA/GSFC Scanning Raman Lidar (SRL) participated in the International H2O Project (IHOP) that occur-red in May and June, 2002 in the midwestern part of the U. S. The SRL acquired measurements of water vapor, aerosols, cloud liquid and ice water, and temperature for more than 200 hours during IHOP. Here we report on the SRL water vapor and cirrus cloud measurements with particular emphasis being given to the measurements of June 19-20, 2002, which are motivating cirrus cloud model comparison studies. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Whiteman, DN (reprint author), NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. NR 7 TC 1 Z9 1 U1 0 U2 0 PU ESA PUBLICATIONS DIVISION C/O ESTEC PI 2200 AG NOORDWIJK PA PO BOX 299, 2200 AG NOORDWIJK, NETHERLANDS SN 0379-6566 BN 92-9092-872-7 J9 ESA SP PUBL PY 2004 VL 561 BP 337 EP 340 PG 4 WC Instruments & Instrumentation; Meteorology & Atmospheric Sciences; Remote Sensing; Optics SC Instruments & Instrumentation; Meteorology & Atmospheric Sciences; Remote Sensing; Optics GA BAP51 UT WOS:000223133500083 ER PT S AU Leblanc, T McDermid, IS Haner, DA Walsh, TD AF Leblanc, T McDermid, IS Haner, DA Walsh, TD BE Pappalardo, G Amodeo, A TI A high capability Raman lidar for upper tropospheric and lower stratospheric water vapor measurements SO 22ND INTERNATIONAL LASER RADAR CONFERENCE (ILRC 2004), VOLS 1 AND 2 SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 22nd International Laser Radar Conference (ILRC 2004) CY JUL 12-16, 2004 CL Matera, ITALY SP ICLAS, Int Coordinat Grp Laser Atmospher Studies, Ist Metodol Analisi Ambientale, Consiglio Nazl Ric, esa, NASA ID OZONE LIDAR; BACKSCATTER; ATMOSPHERE; AEROSOLS AB A new Water Vapor Raman lidar is being built at the Table Mountain Facility (TMF) of the Jet Propulsion Laboratory (JPL) in California (34.4N, 117.7W). The new system is designed to reach accuracies better than 5% anywhere up to 12 km altitude, and with the capability to measure water vapor mixing ratios as low as 1 ppm near the tropopause and in the lower stratosphere. The principal components of the proposed lidar, a high-energy Nd:YAG laser and a large telescope, are already available at TMF. The lidar receiver system, and data acquisition hardware and software are currently being implemented. The initial system in a non-optimized configuration already showed promising results, as water vapor lidar returns were clearly detected Lip to 20 km altitude. The initial configuration, and preliminary results are discussed in this short paper. The optimized configuration of the system, and the first calibrated water vapor profiles obtained from this optimized system will be shown at the conference. C1 CALTECH, Jet Prop Lab, Table Mt Facil, Wrightwood, CA 92397 USA. RP Leblanc, T (reprint author), CALTECH, Jet Prop Lab, Table Mt Facil, POB 367, Wrightwood, CA 92397 USA. NR 12 TC 0 Z9 0 U1 0 U2 0 PU ESA PUBLICATIONS DIVISION C/O ESTEC PI 2200 AG NOORDWIJK PA PO BOX 299, 2200 AG NOORDWIJK, NETHERLANDS SN 0379-6566 BN 92-9092-872-7 J9 ESA SP PUBL PY 2004 VL 561 BP 447 EP 450 PG 4 WC Instruments & Instrumentation; Meteorology & Atmospheric Sciences; Remote Sensing; Optics SC Instruments & Instrumentation; Meteorology & Atmospheric Sciences; Remote Sensing; Optics GA BAP51 UT WOS:000223133500110 ER PT S AU Kuehn, RE Vaughan, MA Winker, D AF Kuehn, RE Vaughan, MA Winker, D BE Pappalardo, G Amodeo, A TI Applying a range dependent multiple scattering correction to retrievals of extinction using lite data SO 22ND INTERNATIONAL LASER RADAR CONFERENCE (ILRC 2004), VOLS 1 AND 2 SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 22nd International Laser Radar Conference (ILRC 2004) CY JUL 12-16, 2004 CL Matera, ITALY SP ICLAS, Int Coordinat Grp Laser Atmospher Studies, Ist Metodol Analisi Ambientale, Consiglio Nazl Ric, esa, NASA ID LIDAR AB In this work we demonstrate the application of an extinction algorithm that incorporates a range dependent multiple scattering parameterization. The particulate-layer average lidar ratio can also be calculated when transmittance measurements of the layer are available. For elevated particulate layers that are not vertically adjacent to other layers. the attenuated molecular signal from above and below the layer can be used to measure its transmittance. For LITE orbit 83, over a region spanning part of the country of Western Sahara and the Atlantic Ocean (25.9N, 14.3W to 27.5N, 15AW), 31 transmittance measurements were possible for an elevated aerosol layer. Using an multiple scattering parameter modelled for dust, the mean retrieved lidar ratio at 532 nm, was 33.7 sr. If no multiple scattering is assumed then mean retrieved lidar ratio was 23.9 sr. In comparison, results from AERONET data indicate that the lidar ratio for dust is 32 sr [1]. and from high spectral resolution lidar are in the range from 42 to 55 sr [2]. C1 NASA, Langley Res Ctr, SAIC, Hampton, VA 23681 USA. RP Kuehn, RE (reprint author), NASA, Langley Res Ctr, SAIC, Mail Stop 435, Hampton, VA 23681 USA. NR 6 TC 0 Z9 0 U1 0 U2 0 PU ESA PUBLICATIONS DIVISION C/O ESTEC PI 2200 AG NOORDWIJK PA PO BOX 299, 2200 AG NOORDWIJK, NETHERLANDS SN 0379-6566 BN 92-9092-872-7 J9 ESA SP PUBL PY 2004 VL 561 BP 475 EP 478 PG 4 WC Instruments & Instrumentation; Meteorology & Atmospheric Sciences; Remote Sensing; Optics SC Instruments & Instrumentation; Meteorology & Atmospheric Sciences; Remote Sensing; Optics GA BAP51 UT WOS:000223133500117 ER PT S AU Vaughan, M Liu, ZY Omar, A AF Vaughan, M Liu, ZY Omar, A BE Pappalardo, G Amodeo, A TI Multi-wavelength analysis of a lofted aerosol layer measured by lite SO 22ND INTERNATIONAL LASER RADAR CONFERENCE (ILRC 2004), VOLS 1 AND 2 SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 22nd International Laser Radar Conference (ILRC 2004) CY JUL 12-16, 2004 CL Matera, ITALY SP ICLAS, Int Coordinat Grp Laser Atmospher Studies, Ist Metodol Analisi Ambientale, Consiglio Nazl Ric, esa, NASA ID LIDAR; SCATTERING; CLOUDS AB A newly developed optimization technique is used to derive lidar ratio at 1064 nm from a lofted aerosol layer measured during the Lidar In-space Technology Experiment (LITE). In addition to the lidar ratio, this optimization scheme simultaneously retrieves the particulate backscatter color ratio, chi = beta(1064) / beta(532). Lidar ratios for the layer were also retrieved at 355 nm and 532 nm using the long-established transmittance method. Combining the information obtained from all retrievals allows LIS to characterize the optical proper-ties of the layer in terms of color ratios for both backscatter and extinction for all wavelength pairs. C1 NASA, Langley Res Ctr, SAIC, Hampton, VA 23681 USA. RP Vaughan, M (reprint author), NASA, Langley Res Ctr, SAIC, Mail Stop 435, Hampton, VA 23681 USA. RI Liu, Zhaoyan/B-1783-2010 OI Liu, Zhaoyan/0000-0003-4996-5738 NR 10 TC 2 Z9 2 U1 0 U2 0 PU ESA PUBLICATIONS DIVISION C/O ESTEC PI 2200 AG NOORDWIJK PA PO BOX 299, 2200 AG NOORDWIJK, NETHERLANDS SN 0379-6566 BN 92-9092-872-7 J9 ESA SP PUBL PY 2004 VL 561 BP 495 EP 498 PG 4 WC Instruments & Instrumentation; Meteorology & Atmospheric Sciences; Remote Sensing; Optics SC Instruments & Instrumentation; Meteorology & Atmospheric Sciences; Remote Sensing; Optics GA BAP51 UT WOS:000223133500122 ER PT S AU De Young, R Notari, A Holmes, A AF De Young, R Notari, A Holmes, A BE Pappalardo, G Amodeo, A TI A new compact aircraft aerosol lidar and recent mission results SO 22ND INTERNATIONAL LASER RADAR CONFERENCE (ILRC 2004), VOLS 1 AND 2 SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 22nd International Laser Radar Conference (ILRC 2004) CY JUL 12-16, 2004 CL Matera, ITALY SP ICLAS, Int Coordinat Grp Laser Atmospher Studies, Ist Metodol Analisi Ambientale, Consiglio Nazl Ric, esa, NASA AB A compact aerosol lidar operating at both 532 and 1064 nm has been developed and deployed for aircraft-and ground-based atmospheric aerosol measurements. Both analog and photon counting detection is used to provide high spatial resolution aerosol profiles. Three recent missions demonstrate the utility of this system. Missions include aircraft measurements of aerosol profiles in the California San Joaquin Valley, as well as Atlantic Ocean aerosol aircraft measurements and ground-based correlative measurements with the orbiting GLAS laser oil the ICESat satellite. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP De Young, R (reprint author), NASA, Langley Res Ctr, MS 401A, Hampton, VA 23681 USA. NR 4 TC 0 Z9 0 U1 0 U2 0 PU ESA PUBLICATIONS DIVISION C/O ESTEC PI 2200 AG NOORDWIJK PA PO BOX 299, 2200 AG NOORDWIJK, NETHERLANDS SN 0379-6566 BN 92-9092-872-7 J9 ESA SP PUBL PY 2004 VL 561 BP 507 EP 510 PG 4 WC Instruments & Instrumentation; Meteorology & Atmospheric Sciences; Remote Sensing; Optics SC Instruments & Instrumentation; Meteorology & Atmospheric Sciences; Remote Sensing; Optics GA BAP51 UT WOS:000223133500125 ER PT S AU Browell, EV Fenn, MA Grant, WB Avery, MA Roland, N McGee, TJ Twigg, LW Trepte, CR Steinhorst, H Butler, CF Kooi, SA Notari, A Hair, JW Lait, LR AF Browell, EV Fenn, MA Grant, WB Avery, MA Roland, N McGee, TJ Twigg, LW Trepte, CR Steinhorst, H Butler, CF Kooi, SA Notari, A Hair, JW Lait, LR BE Pappalardo, G Amodeo, A TI Ozone variations and changes in the Arctic and comparisons of various ozone profile measurements during SOLVE-II SO 22ND INTERNATIONAL LASER RADAR CONFERENCE (ILRC 2004), VOLS 1 AND 2 SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 22nd International Laser Radar Conference (ILRC 2004) CY JUL 12-16, 2004 CL Matera, ITALY SP ICLAS, Int Coordinat Grp Laser Atmospher Studies, Ist Metodol Analisi Ambientale, Consiglio Nazl Ric, esa, NASA AB Airborne Differential Absorption Lidar (DIAL) measurements of ozone distributions made in the Arctic winter polar vortex were used to estimate the magnitude of ozone loss during January and early February 2003. The maximum ozone loss was found to be 18-22% at a potential temperature of 475K. Significant ozone loss was also observed in sunlit portion of vortex in early January. Simultaneous measurements of ozone profiles by satellite, airborne and ground-based instruments were also compared during this field experiment. The comparisons with the SAGE-III satellite measurements showed agreement to within 10% from 10-24 km. C1 ASA, Langley Res Ctr, Atmospher Sci Res, Hampton, VA 23692 USA. RP Browell, EV (reprint author), ASA, Langley Res Ctr, Atmospher Sci Res, MS401-A, Hampton, VA 23692 USA. OI Grant, William/0000-0002-1439-3285 NR 1 TC 0 Z9 0 U1 0 U2 3 PU ESA PUBLICATIONS DIVISION C/O ESTEC PI 2200 AG NOORDWIJK PA PO BOX 299, 2200 AG NOORDWIJK, NETHERLANDS SN 0379-6566 BN 92-9092-872-7 J9 ESA SP PUBL PY 2004 VL 561 BP 555 EP 557 PG 3 WC Instruments & Instrumentation; Meteorology & Atmospheric Sciences; Remote Sensing; Optics SC Instruments & Instrumentation; Meteorology & Atmospheric Sciences; Remote Sensing; Optics GA BAP51 UT WOS:000223133500137 ER PT S AU Browell, EV Butler, CF Grant, WB Notari, A Kooi, SA Lait, LR AF Browell, EV Butler, CF Grant, WB Notari, A Kooi, SA Lait, LR BE Pappalardo, G Amodeo, A TI Comparison of polar stratospheric cloud properties observed with airborne lidar during SOLVE I and SOLVE II SO 22ND INTERNATIONAL LASER RADAR CONFERENCE (ILRC 2004), VOLS 1 AND 2 SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 22nd International Laser Radar Conference (ILRC 2004) CY JUL 12-16, 2004 CL Matera, ITALY SP ICLAS, Int Coordinat Grp Laser Atmospher Studies, Ist Metodol Analisi Ambientale, Consiglio Nazl Ric, esa, NASA AB The SAGE-III Ozone Loss and Validation Experiments (SOLVE) were conducted over the Arctic from 29 November 1999 to 16 March 2000 (SOLVE 1) and from 9 January to 12 February 2003 (SOLVE 11). During these campaigns, a multiple-wave length lidar system was operated from the NASA DC-8 aircraft to make measurements of background aerosols and polar stratospheric clouds (PSCs) on long-range flights across the wintertime polar vortex. Aerosol backscatter measurements were made at 1064, 622, and 311 nm and aerosol depolarization measurements were made at 1064 (SOLVE I only) and 622 nm. Meteorological analyses from the NASA Goddard Global Modeling and Assimilation Office were also used in this investigation. This paper presents results on the frequency of observation and spatial characteristics of the PSCs observed during the SOLVE campaigns. Optical characteristics of the PSCs are discussed, and their observations are related to temperature distributions and other meteorological conditions. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Browell, EV (reprint author), NASA, Langley Res Ctr, MS 401A, Hampton, VA 23681 USA. OI Grant, William/0000-0002-1439-3285 NR 4 TC 0 Z9 0 U1 0 U2 0 PU ESA PUBLICATIONS DIVISION C/O ESTEC PI 2200 AG NOORDWIJK PA PO BOX 299, 2200 AG NOORDWIJK, NETHERLANDS SN 0379-6566 BN 92-9092-872-7 J9 ESA SP PUBL PY 2004 VL 561 BP 577 EP 580 PG 4 WC Instruments & Instrumentation; Meteorology & Atmospheric Sciences; Remote Sensing; Optics SC Instruments & Instrumentation; Meteorology & Atmospheric Sciences; Remote Sensing; Optics GA BAP51 UT WOS:000223133500142 ER PT S AU McGee, TJ Twigg, L Sumnicht, G Hoegy, W Burris, J Silbert, D Heaps, W Neuber, R Trepte, CR AF McGee, TJ Twigg, L Sumnicht, G Hoegy, W Burris, J Silbert, D Heaps, W Neuber, R Trepte, CR BE Pappalardo, G Amodeo, A TI Arotal ozone and temperature vertical profile measurements from the NASA DC-8 during the SOLVE II campaign SO 22ND INTERNATIONAL LASER RADAR CONFERENCE (ILRC 2004), VOLS 1 AND 2 SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 22nd International Laser Radar Conference (ILRC 2004) CY JUL 12-16, 2004 CL Matera, ITALY SP ICLAS, Int Coordinat Grp Laser Atmospher Studies, Ist Metodol Analisi Ambientale, Consiglio Nazl Ric, esa, NASA AB The AROTAL instrument (Airborne Raman Ozone Temperature and Aerosol Lidar) - a collaboration between scientists at NASA Goddard Space Flight Center, and Langley Research Center - was flown on the NASA DC-8 during the SOLVE II campaign during January and February, 2003. The flights were flown from the Arena Arctica in Kiruna, Sweden. We report measurements of temperature and ozone profiles showing approximately a 600 ppbv loss in ozone near 17.5 km, over the time frame of the aircraft campaign. Comparisons of ozone profiles from AROTAL are made with the SAGE III instrument. C1 NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. RP McGee, TJ (reprint author), NASA, Goddard Space Flight Ctr, Atmospheres Lab, Greenbelt, MD 20771 USA. NR 0 TC 0 Z9 0 U1 0 U2 1 PU ESA PUBLICATIONS DIVISION C/O ESTEC PI 2200 AG NOORDWIJK PA PO BOX 299, 2200 AG NOORDWIJK, NETHERLANDS SN 0379-6566 BN 92-9092-872-7 J9 ESA SP PUBL PY 2004 VL 561 BP 581 EP 582 PG 2 WC Instruments & Instrumentation; Meteorology & Atmospheric Sciences; Remote Sensing; Optics SC Instruments & Instrumentation; Meteorology & Atmospheric Sciences; Remote Sensing; Optics GA BAP51 UT WOS:000223133500143 ER PT S AU Ferrare, R Browell, E Ismail, S Kooi, S Brackett, V Revercomb, H Knuteson, B Antonelli, P Misch, N Gleason, J Nguyen, E Currens, S AF Ferrare, R Browell, E Ismail, S Kooi, S Brackett, V Revercomb, H Knuteson, B Antonelli, P Misch, N Gleason, J Nguyen, E Currens, S BE Pappalardo, G Amodeo, A TI Airborne lidar measurements of water vapor and aerosol fields over the southern great plains during the IHOP field experiment SO 22ND INTERNATIONAL LASER RADAR CONFERENCE (ILRC 2004), VOLS 1 AND 2 SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 22nd International Laser Radar Conference (ILRC 2004) CY JUL 12-16, 2004 CL Matera, ITALY SP ICLAS, Int Coordinat Grp Laser Atmospher Studies, Ist Metodol Analisi Ambientale, Consiglio Nazl Ric, esa, NASA AB Water vapor and aerosol profiles from NASA's Lidar Atmospheric Sensing Experiment (LASE) system acquired during the International H2O Project (IHOP) are used to characterize water vapor and aerosols over the U.S. Southern Great Plains (SGP) region. LASE water vapor profiles are used to derive profiles of equivalent potential temperature and relative humidity as well as distributions of Convective Available Potential Energy (CAPE)(dagger) and Convective Inhibition (CIN)(dagger) in order to help understand the role of water vapor on convective initiation. LASE aerosol scattering ratio profiles are used in conjunction with Terra Moderate Resolution Imaging Spectroradiometer (MODIS) retrievals of aerosol optical thickness to examine the distribution of aerosols over the Southern Great Plains (SGP). These datasets show the presence of smoke from forest fires in New Mexico and Colorado. The LASE data and other IHOP datasets are used to create visualizations of the water vapor and aerosol fields in order to gain a better understanding of the three dimensional distributions of water vapor and aerosols over the Southern Great Plains. C1 NASA, Langley Res Ctr, Hampton, VA 23681 USA. RP Ferrare, R (reprint author), NASA, Langley Res Ctr, MS 401A, Hampton, VA 23681 USA. NR 6 TC 0 Z9 0 U1 0 U2 0 PU ESA PUBLICATIONS DIVISION C/O ESTEC PI 2200 AG NOORDWIJK PA PO BOX 299, 2200 AG NOORDWIJK, NETHERLANDS SN 0379-6566 BN 92-9092-872-7 J9 ESA SP PUBL PY 2004 VL 561 BP 653 EP 656 PG 4 WC Instruments & Instrumentation; Meteorology & Atmospheric Sciences; Remote Sensing; Optics SC Instruments & Instrumentation; Meteorology & Atmospheric Sciences; Remote Sensing; Optics GA BAP51 UT WOS:000223133500160 ER PT S AU De Young, R Grant, WB Severance, K Thornton, C AF De Young, R Grant, WB Severance, K Thornton, C BE Pappalardo, G Amodeo, A TI Aerosol transport in the California Central Valley observed by airborne lidar SO 22ND INTERNATIONAL LASER RADAR CONFERENCE (ILRC 2004), VOLS 1 AND 2 SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 22nd International Laser Radar Conference (ILRC 2004) CY JUL 12-16, 2004 CL Matera, ITALY SP ICLAS, Int Coordinat Grp Laser Atmospher Studies, Ist Metodol Analisi Ambientale, Consiglio Nazl Ric, esa, NASA ID OZONE AB A new aerosol lidar system was deployed on the NASA DC-8 in May-June of 2003 and was used to measure the aerosol profiles in the California Central Valley. The lidar operated at 532 and 1064 nm at a PRF of 20 Hz. The resulting aerosol profiles were plotted in a unique three-dimensional format that allowed the visual observation of the aerosol profiles, the valley topography, and the corresponding backward trajectory air masses. The accumulation of aerosols can be seen in the southern end of the valley due to topography and winds. C1 NASA, Langley Res Ctr, Atmospher Sci Res, Hampton, VA 23681 USA. RP De Young, R (reprint author), NASA, Langley Res Ctr, Atmospher Sci Res, Hampton, VA 23681 USA. OI Grant, William/0000-0002-1439-3285 NR 9 TC 1 Z9 1 U1 0 U2 1 PU ESA PUBLICATIONS DIVISION C/O ESTEC PI 2200 AG NOORDWIJK PA PO BOX 299, 2200 AG NOORDWIJK, NETHERLANDS SN 0379-6566 BN 92-9092-872-7 J9 ESA SP PUBL PY 2004 VL 561 BP 691 EP 694 PG 4 WC Instruments & Instrumentation; Meteorology & Atmospheric Sciences; Remote Sensing; Optics SC Instruments & Instrumentation; Meteorology & Atmospheric Sciences; Remote Sensing; Optics GA BAP51 UT WOS:000223133500169 ER PT S AU Gentry, BM Chen, HL Li, SX Mathur, S Dobler, J Hasselbrack, W Comer, J AF Gentry, BM Chen, HL Li, SX Mathur, S Dobler, J Hasselbrack, W Comer, J BE Pappalardo, G Amodeo, A TI Wind profiles obtained with a molecular direct detection doppler lidar during IHOP-2002 SO 22ND INTERNATIONAL LASER RADAR CONFERENCE (ILRC 2004), VOLS 1 AND 2 SE ESA SPECIAL PUBLICATIONS LA English DT Proceedings Paper CT 22nd International Laser Radar Conference (ILRC 2004) CY JUL 12-16, 2004 CL Matera, ITALY SP ICLAS, Int Coordinat Grp Laser Atmospher Studies, Ist Metodol Analisi Ambientale, Consiglio Nazl Ric, esa, NASA ID VALIDATION AB The Goddard Lidar Observatory for Winds (GLOW) is a mobile direct detection Doppler lidar system which uses the double edge technique to measure the Doppler shift of the molecular backscattered laser signal at a wavelength of 355 nm. In the spring of 2002 GLOW was deployed to the western Oklahoma profiling site (36degrees 33.500' N, 100degrees 36.371' W) to participate in the International H2O Project (IHOP). During the IHOP campaign over 240 hours of wind profiles were obtained with the GLOW lidar in support of a variety of scientific investigations. C1 NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA. RP Gentry, BM (reprint author), NASA, Goddard Space Flight Ctr, Code 912, Greenbelt, MD 20771 USA. NR 8 TC 1 Z9 1 U1 1 U2 1 PU ESA PUBLICATIONS DIVISION C/O ESTEC PI 2200 AG NOORDWIJK PA PO BOX 299, 2200 AG NOORDWIJK, NETHERLANDS SN 0379-6566 BN 92-9092-872-7 J9 ESA SP PUBL PY 2004 VL 561 BP 731 EP 733 PG 3 WC Instruments & Instrumentation; Meteorology & Atmospheric Sciences; Remote Sensing; Optics SC Instruments & Instrumentation; Meteorology & Atmospheric Sciences; Remote Sensing; Optics GA BAP51 UT WOS:000223133500178 ER EF